USOO887 1843B2

(12) United States Patent (10) Patent No.: US 8,871,843 B2 Lee (45) Date of Patent: Oct. 28, 2014

(54) HALOGEN-FREE FLAME RETARDANT 5,456,984 A 10/1995 Bishop et al. MATERAL 5,484,830 A 1/1996 Staendeke 5,648.436 A 7/1997 Janowitz et al. 5,925,700 A 7/1999 Imahashi (75) Inventor: Jean L. Lee, San Jose, CA (US) 5,955, 184 A 9, 1999 Honda et al. 5,994,429 A 11/1999 Honda et al. (73) Assignee: Apple Inc., Cupertino, CA (US) 6,140,411 A 10/2000 Schwanborn et al. 6,355,767 B1 * 3/2002 Takagi ...... 528,196 (*) Notice: Subject to any disclaimer, the term of this 6,440,567 B1 8, 2002 Choate et al. 6,495,244 B1 12/2002 Andresakis et al. patent is extended or adjusted under 35 6,518,336 B1 2/2003 Yabuhara et al. U.S.C. 154(b) by 190 days. 6,642,288 B1 1 1/2003 Hulskotte 6,755,995 B1 6/2004 Hasegawa et al. (21) Appl. No.: 12/638,489 6,767,941 B2 7/2004 Van Der Speket al. 6,809,130 B2 10/2004 Chiou et al. 6,894, 101 B2 5, 2005 Paul et al. (22) Filed: Dec. 15, 2009 6,916,539 B2 7/2005 Cooray et al. 6,998,536 B2 2/2006 Barusseau et al. (65) Prior Publication Data 7,053,145 B1 5/2006 Tasaka et al. US 2011/O144244A1 Jun. 16, 2011 7,115,678 B2 10/2006 Ihara et al. 7,279.520 B2 10/2007 Hausmann et al. 7,323,504 B2 1/2008 Steenbakkers-Menting et al. (51) Int. Cl. 7,368,495 B2 5/2008 Ihara et al. CSK 3/28 (2006.01) 7,456,235 B2 11/2008 Heschke et al. CSK 3/22 (2006.01) 7.495,174 B2 2/2009 Hase et al.

7,939,591 B2* 5/2011 Tomoda ...... 524,284 C08K 3/26 (2006.01) 2001/00 16615 A1 8/2001 Sobkin et al...... 524.91 C08K 3/34 (2006.01) 2002fO155348 A1 10, 2002 Gitto CSK 3/38 (2006.01) 2005/008O165 A1* 4/2005 Gabriel ...... 523,220 CSK5/05 (2006.01) 2006/0245607 A1 1 1/2006 Kynnos CSK 5/535 (2006.01) 2009, O151984 A1 6/2009 Fujimura CSK 5/545 (2006.01) CSK 5/7 (2006.01) FOREIGN PATENT DOCUMENTS CSK 5/45 (2006.01) WO WO 2006 123833 A1 * 11, 2006 COSL23/06 (2006.01) CSK 3/00 (2006.01) * cited by examiner COSL23/02 (2006.01) COSL 53/OO (2006.01) Primary Examiner — Angela C Scott (52) U.S. Cl. (74) Attorney, Agent, or Firm — Brownstein Hyatt Farber CPC ...... C08K 3/0058 (2013.01); C08L 23/06 Schreck, LLP (2013.01); C08L 53/00 (2013.01); C08L 23/02 (2013.01); C08K 3/34 (2013.01) (57) ABSTRACT USPC ...... 524/186; 524/429; 524/492 The disclosure describes halogen free flame retardant resin (58) Field of Classification Search compositions comprising at least one thermoplastic polymer; USPC ...... 524/186, 429, 492 an inorganic filler; and a flame retardant additive, wherein the See application file for complete search history. flame retardant additive is an alkali metal nitrite; an alkaline earth metal nitrite; an alkali metal nitride; an alkaline earth (56) References Cited metal nitride; an alkali metal borate; an alkaline earth metal borate; an alkali metal silicide; an alkaline earth metal sili U.S. PATENT DOCUMENTS cide; an alkali metal silicate; or an alkaline earth metal sili 4,869,848 A 9/1989 Hasegawa et al. cate. Also described are computing systems having compo 4,879,332 A 11, 1989 Saito et al. nents formed of Such a halogen free, flame retardant resin. 4,996,255 A 2f1991 Davis et al. 5,286,775 A 2/1994 Bandyopadhyay 11 Claims, 1 Drawing Sheet U.S. Patent Oct. 28, 2014 US 8,871,843 B2

US 8,871,843 B2 1. 2 HALOGEN-FREE FLAME RETARDANT The inorganic filler can be one or more of carbon black, MATERAL white carbon, silica, Zirconium silicate, alumina, hydrated alumina, aluminum trihydrate, hydrated magnesium, barium BACKGROUND Sulfate, barium titanate, titanium oxide, magnesium oxide, molybdenum oxide, tin oxide, Zinc oxide, talc, mica, glass It has been estimated that about 10% of fires are caused by beads, hollow glass balls, clay, silicone oil, quartz, barium electrical faults of wiring and electrical equipment, and that carbonate, calcium carbonate, or magnesium carbonate. In these fires account for 19% of fire-related injuries. Some Some embodiments, one or more of such inorganic fillers can plastics are inherently resistant to fire. Such as polyvinylchlo also be excluded from the composition. The inorganic filler 10 can be present, for example, in about 1 wt.% to about 30 wt. ride (PVC). However, PVC is not suitable for many electron % of the composition. ics applications. Only about 12% of plastics used today con In some embodiments, the flame retardant additive can tain flame retardants. An increased use of flame retardants include an alkali metal nitrite or an alkaline earth metal would improve the safety of electrical wiring and electronic nitrite. The alkali metal nitrite or alkaline earth metal nitrite devices, and therefore reduce the number of fires caused by 15 can be, for example, lithium nitrite, Sodium nitrite, potassium electronic devices. nitrite, magnesium nitrite, or calcium nitrite. Halogenated flame retardants have been found to be effec In some embodiments, the flame retardant additive can tive in many plastics. However, environmental and health include an alkali metal nitride or an alkaline earth metal concerns have caused halogenated flame retardants to be less nitride. The alkali metal nitride or alkaline earth metal nitride desirable for electronic devices, and they are being increas can be, for example, lithium nitride, magnesium nitride, ingly regulated. beryllium nitride, or calcium nitride. A wide variety of flame retardant resin compositions have In some embodiments, the flame retardant additive can been developed to ensuring safety against fire, including include an alkali metal borate or an alkaline earth metal halogen free flame retardant resin compositions. Generally, borate. The alkali metal borate or alkaline earth metal borate halogen free flame resisting resin compositions contain inor 25 can be, for example, sodium metaborate, Sodium tetraborate, ganic fillers, such as aluminum hydroxide or magnesium NaBas, Na-Bo, NaBs, calcium aluminum triborate (jo hydroxide. The amount of the inorganic filler required to hachidolite), magnesium diboride, Suanite; johachidolite; obtain sufficiently high flame resisting effect is generally 30 LiBO: LiBO: CaBO; sodium metaborate; sodium tet to 70% by weight based of the composition. However, a raborate; NaBO(OH)4.8H2O, or disodium octaborate synthetic resin composition containing Such high contents of 30 tetrahydrate. inorganic filler generally do not exhibit Suitable physical In some embodiments, the flame retardant additive can characteristics, such as well-balanced strength, resulting in include an alkali metal silicide or an alkaline earth metal brittle products with poor processability. Accordingly, there silicide. The alkali metal silicide or alkaline earth metal sili is a need for new halogen-free flame retardants, as well as new cide can be, for example, Sodium silicide, potassium silicide, halogen-free plastics and resin materials. 35 rubidium silicide, cesium silicide magnesium silicide, or cal cium silicide. SUMMARY In some embodiments, the flame retardant additive can include an alkali metal silicate or an alkaline earth metal The invention provides halogen-free flame retardants, res silicate. The alkali metal silicate or alkaline earth metal sili ins that include halogen free flame retardants, and plastic 40 cate can be, for example, thaumasite, olivine; or epidote. components made from Such materials. In some embodi Any given embodiment can also include an antioxidant, ments, the invention relates to a composite resin molded Such as an amino acid, vitaminA, vitamin E, ascorbic acid, or article having excellent flame retardancy, electric insulation lipoic acid. Antioxidants can be included in about 0.5 parts to properties, and crack resistance, and produces only negligible 15 parts by weight, or in about any 0.5 part increment within amounts of toxic Substances during incineration, if any at all. 45 Such a range. In some embodiments, the composition can Accordingly, the invention provides a halogen free resin have a melt index of for example, about 0.1 g/10 minutes to composition that includes at least one thermoplastic polymer; about 10.0 g/10 minutes. an inorganic filler; and a flame retardant additive, wherein the In some embodiments, a halogen free resin composition flame retardant additive comprises an alkali metal nitrite; an includes about 70 parts to 30 parts by weight of at least one alkaline earth metal nitrite; an alkali metal nitride; an alkaline 50 thermoplastic polymer; about 30 parts to 70 parts by weight of earth metal nitride; an alkali metal borate; an alkaline earth an inorganic filler; and about 0.5 parts to 15 parts by weight of metal borate; an alkali metal silicide; an alkaline earth metal a flame retardant additive, wherein the flame retardant addi silicide; an alkali metal silicate; an alkaline earth metal sili tive includes an alkali metal nitrite; an alkaline earth metal cate; or a combination thereof. nitrite; an alkali metal nitride; an alkaline earth metal nitride; The thermoplastic polymer can include one or more of 55 analkali metal borate; analkaline earth metal borate; analkali polyethylene (PE); ethylene-vinyl acetate copolymer (EVA): metal silicide; an alkaline earth metal silicide; an alkali metal ethylene-ethyl acrylate copolymer (EEA): ethylene-methyl silicate; an alkaline earth metal silicate; or a combination methacrylate copolymer (EMMA); polypropylene (PP); thereof. polystyrene (PS); polyacrylonitrile; acrylonitrile-butadiene The invention further provides a computing system, input styrene copolymer (ABS); nylon-6: nylon-6.6; polycarbonate 60 device, or computer component comprising any of the com (PC); polyurethane; biaxially-oriented polyethylene tereph positions described above or herein. For example, a comput thalate (boPET) polyester; ethylene-C-olefin copolymer; eth ing system can include at least one component selected from ylene-vinyl ester copolymers; ethylene-C.f3-unsaturated car the group consisting essentially of a housing, an input device, boxylic acid alkyl ester copolymers; poly(acrylic acid); or and a cable, wherein the component includes a halogen free polyphenylene sulphone (PPS). The thermoplastic polymer 65 resin, that includes at least one thermoplastic polymer; an can be present, for example, in about 30 wt.% to about 70 wt. inorganic filler; and a flame retardant additive, wherein the % of the composition. flame retardant additive comprises an alkali metal nitrite; an US 8,871,843 B2 3 4 alkaline earth metal nitrite; an alkali metal nitride; an alkaline is described in connection with an embodiment, it is within earth metal nitride; an alkali metal borate; an alkaline earth the knowledge of one skilled in the art to affect such aspect, metal borate; an alkali metal silicide; an alkaline earth metal feature, structure, moiety, or characteristic in connection with silicide; an alkali metal silicate; an alkaline earth metal sili other embodiments, whether or not explicitly described. cate; or a combination thereof. The term “and/or” means any one of the items, any com In some embodiments, a flame retardant resin is provided bination of the items, or all of the items with which this term that does not include carbon black. The resins are therefore is associated. widely applicable to the fields where colored products are The singular forms “a,” “an and “the include plural desirable. Such as products where appearance has commer reference unless the context clearly dictates otherwise. Thus, cial significance. Examples of such products include personal 10 for example, a reference to “a compound includes a plurality electronic devices, such as personal computers, laptop com of such compounds, so that a compound Xincludes a plurality puters, cell phones, personal digital assistants, electronic of compounds X. It is further noted that the claims may be games, and the like. drafted to exclude any optional element. As such, this state The invention also relates to a self-fire extinguishable, ment is intended to serve as antecedent basis for use of Such halogen-free and flame resisting synthetic resin composition. 15 exclusive terminology as “solely.” “only, and the like in Such a composition can be obtained by adding 0.5 to 15 parts connection with the recitation of claim elements, or use of a by weight of a flame retardant additive as described herein to “negative' limitation. a mixture comprising 70 to 30 parts by weight of a thermo The term “about can refer to a variation of +5%, +10%, plastic synthetic resin and 30 to 70 parts by weight of an +20%, or +25% of the value specified. For example, “about inorganic filler, Such as magnesium hydroxide or aluminum 50 percent can in some embodiments carry a variation from hydroxide having an average particle size of 0.1 to 10 Lum. 45 to 55 percent. For integer ranges, the term “about can The flame retardant materials can be effective flame retar include one or two integers greater than and/or less than a dants in standard and technical plastics, thermosets, textiles, recited integer. Unless indicated otherwise herein, the term and rubbers. The invention also provides a prepreg impreg "about is intended to include values, e.g., weight percents, nated with the halogen-free flame-retardant epoxy resin com 25 proximate to the recited range that are equivalent in terms of position according to the invention as well as a laminate, the functionality of the individual ingredient, the composi copper-clad laminate and printed wiring board prepared by tion, or the embodiment. using the prepreg. As will be understood by one skilled in the art, for any and all purposes, particularly in terms of providing a written BRIEF DESCRIPTION OF THE DRAWINGS 30 description, all ranges disclosed herein also encompass any and all possible Subranges and combinations of Subranges The following drawing forms part of the specification and thereofas well as the individual values making up the range, is included to further demonstrate certain embodiments or particularly integer values. A recited range (e.g., weight per various aspects of the invention. In some instances, embodi cents or carbon groups) includes each specific value, integer, ments of the invention can be best understood by referring to 35 decimal, or identity within the range. Any listed range can be the accompanying drawing in combination with the detailed easily recognized as Sufficiently describing and enabling the description presented herein. The description and accompa same range being broken down into at least equal halves, nying drawing may highlight a certain specific example, or a thirds, quarters, fifths, tenths, etc. As a nonlimiting example, certain aspect of the invention, however, one skilled in the art each range discussed herein can be readily broken down into will understand that portions of the example or aspect may be 40 a lower third, middle third and upper third, etc. As will also be used in combination with other examples or aspects of the understood by one skilled in the art, all language Such as “up invention. to.” “at least.” “greater than.” “less than.” “more than.” “or FIG. 1 illustrates an example computing system of a type more' and the like include the number recited and refer to that can include parts made of and that can benefit from use ranges which can be subsequently broken down into Sub of a halogen free resin composition as described herein, in 45 ranges as discussed above. In the same manner, all ratios one illustrative operating configuration. disclosed herein also include all subratios falling within the broader ratio. DETAILED DESCRIPTION One skilled in the art will also readily recognize that where members are grouped together in a common manner, such as Definitions 50 in a Markush group, the invention encompasses not only the entire group listed as a whole, but each member of the group As used herein, certain terms have the following meanings. individually and all possible subgroups of the main group. All other terms and phrases used in this specification have Additionally, for all purposes, the invention encompasses not their ordinary meanings as one of skill in the art would under only the main group, but also the main group absent one or stand. Such ordinary meanings may be obtained by reference 55 more of the group members. The invention also envisages the to technical dictionaries, such as Hawley's Condensed explicit exclusion of one or more of any of the group members Chemical Dictionary 14" Edition, by R.J. Lewis, John Wiley in the claimed invention. & Sons, New York, N.Y., 2001. As will be understood by the skilled artisan, all numbers, References in the specification to “one embodiment”, “an including those expressing quantities of ingredients, proper embodiment”, “an example embodiment’, etc., indicate that 60 ties such as molecular weight, reaction conditions, and so the embodiment described may include a particular aspect, forth, are approximations and understood as being modified feature, structure, moiety, or characteristic, but not every in all instances by the term “about.” These values can vary embodiment necessarily includes that aspect, feature, struc depending upon the desired properties sought to be obtained ture, moiety, or characteristic. Moreover, such phrases may, by those skilled in the art utilizing the teachings of the inven but do not necessarily, refer to the same embodiment referred 65 tion. It is also understood that such values inherently contain to in other portions of the specification. Further, when a variability necessarily resulting from the standard deviations particular aspect, feature, structure, moiety, or characteristic found in their respective testing measurements. US 8,871,843 B2 5 6 The phrase “one or more' is readily understood by one of materials do not break down into gases, they merely Smolder skill in the art, particularly when read in context of its usage. and often self extinguish. An example of self extinguishing is For example, one or more Substituents on a phenyl ring refers when a solid chars and forms a stable carbonaceous barrier to one to five, or one to up to four, for example if the phenyl that prevents access of a flame to the underlying material. ring is disubstituted. However, once flammable gases from a solid ignite, the heat The term “contacting refers to the act of touching, making generated can often break down long-chain solid molecules contact, or of bringing to immediate or close proximity, (e.g., polymer chains) into Smaller molecules that transpire as including at the molecular level, for example, to bring about gases, fueling the fire. The gas flame itself is maintained by a chemical reaction, or a physical change, e.g., on the Surface the action of high energy radicals (H. and OH. in the gas of a solid or in the gas phase near the Surface of a solid. 10 phase), which decompose nearby molecules to produce free Specific values listed below for radicals, substituents, and carbon, which then reacts with oxygen in the air to burn, ranges, are for illustration only; they do not exclude other generating additional heat energy. defined values or other values within defined ranges for radi Flame retardants work by preventing the release of flam cals and Substituents. mable gases from a material when an amount of heat capable The term “halogen free” refers to a composition that 15 of igniting the material is applied. Depending on the specific includes less than 900 parts per million of halogen content, molecule that is decomposed by high energy ions, flammable including, for example, the cumulative mass of chlorine gases Such as O. are often released, further Sustaining a flame. containing and bromine-containing components (i.e., the Flame retardants act by effectively removing the H. and OH. mass of the chlorine-containing and bromine-containing radicals in the gas flame phase. This action considerably components added to the resin formulation). slows or prevents the burning process, thus reducing heat Description of the Halogen Free Flame Retardant Composi generation and the production of further gaseous flammable tions. material. As consumer electronics manufacturers phase out the use Char Formation. The flame retardant compositions of brominated and chlorinated flame retardant materials due described herein can act efficiently in the solid phase of to environmental concerns, alternate materials must be devel 25 burning materials. When heated, the flame retardants can oped to fill the Void. The compositions described herein pro react to produce high energy radical quenching agents. Such vide halogen-free (HF) flame retardant materials by introduc as low energy radicals or acids. The low energy radicals or ing alkali or alkaline earth metal nitrites, nitrides, borides, acids can cause the Solid material to further polymerize and/ and/or silicates into materials, such as cross-linked polyeth or char, forming a glassy layer, thereby inhibiting the pyroly ylene (often used for electrical cablejackets and the like). The 30 sis process that could feed any flames. HF flame retardant materials can Suppress combustion by By this mode of action the amount of fuel produced is scavenging free radicals released during combustion that help significantly diminished, because char rather than combus propagate burning, or by forming a protective non-flammable tible gas is formed. The resulting intumescent char layer plays coating on a material. HF flame retardant materials have significant roles in the flame retardant process. It acts as a wide-spread applications, and provide environmentally 35 two-way barrier, both hindering the passage of the combus friendly products. tible gases and molten polymer toward the flame, and shield Typically, flame retardants work by preventing the release ing the polymer from the heat of the flame. The amount of fuel of flammable gases from a material when heat is applied. This available for the fire is also significantly diminished, because disclosure provides retardants directed at neutralizing high char, rather than combustible gas, is formed. energy ions in a flame that can otherwise decompose mol 40 Flame Retardant Compositions. The flame retardant resin ecules in the material that further sustain flame, materials compositions described herein can prevent the release of additives that, when exposed to heat, formalayer on top of the flammable gases from a material, or reduce their energy, by a material that hinders the release of flammable gases from the variety of mechanisms. The flame retardant additive in the material and shields the material from the flame, and material resin composition can neutralize high energy ions (e.g., H') additives that release water or non-flammable gases upon 45 found in a flame, which can otherwise decompose molecules exposure to heat. in the material into flammable gasses. The flame retardant Accordingly, the disclosure provides halogen free flame additive, when exposed to heat, can also form a layer on top of retardant resins that include a flame retardant material addi a solid material that hinders the release of flammable gases tive. The flame retardant additives can be one or more of: from the material and shields the material from the flame. The an alkali or alkaline earth nitride; 50 flame retardant additive can also release water or non-flam an alkali or alkaline earth nitrite; mable gases upon exposure to heat. The flame retardant addi an alkali or alkaline earthborate; tive can promote cross-linking in polymers, thereby render an alkali or alkaline earth silicide; ing the polymer less Susceptible to decomposition, it can an alkali and alkaline earth silicate; absorb excess heat from combustible gases. The flame retar an antioxidant compound. Such as amino acids (e.g., glu 55 dants described herein can act singly or in combination. tathione), polyphenols, carotenoids, tocotrienols, ascorbic Synthetic Resins of the Flame Retardant Compositions. acid, and/or lipoic acid; or salts thereof; Any suitable polymer or resin can be used to prepare the or a combination thereof. compositions and apparatuses described herein. The resins The flame retardant additives can be added to a resin to used in the flame retardant compositions can include thermo Scavenge high energy ions that may be released by a burning 60 plastic or thermoset polymers, and/or copolymers thereof. resin. The flame retardant resins can be used to provide flame Typical synthetic resins used are thermoplastic resins. proof or flame resistant apparatuses constructed of a halogen Examples include crystalline polyolefins such as polyethyl free flame retardant material as described herein. ene (PE), such as low-density polyethylene (LDPE), very low Flame Retardant Activity. Solid materials do not burn density polyethylene (VLDPE), linear low-density polyeth directly. They first decompose by heat (e.g., pyrolysis) to 65 ylene (LLDPE), or high-density polyethylene (HDPE); eth release flammable gases. Visible flames appear when these ylene-vinyl acetate copolymer (EVA); ethylene-ethyl acry flammable gases react with oxygen (O) in the air. If solid late copolymer (EEA): ethylene-methyl methacrylate US 8,871,843 B2 7 8 copolymer (EMMA); polypropylene (PP); polystyrene (PS): a cyanate ester polymer, and a polyimide resin can be given. polyacrylonitrile; acrylonitrile-butadiene-styrene copolymer These polymers may be used either alone or in combinations (ABS); nylon-6; and nylon-6.6. Other examples include poly of two or more. carbonate (PC), polyurethane, biaxially-oriented polyethyl In some embodiments, the weight average molecular ene terephthalate (boPET) polyester (e.g., Mylar R polyes weight (Mw) of a polymer can be about 10,000 to 250,000, or ter), ethylene-C-olefin copolymer, ethylene-vinyl ester about 15,000 to 150,000, or about 20,000 to 100,000. The copolymers, ethylene-C.B-unsaturated carboxylic acid alkyl weight-average molecular weight of a block copolymers ester copolymers, poly(acrylic acid), and polyphenylene Sul used. Such as (hydrogenated) block copolymer, can also be phone (PPS). Of course, combinations of such polymers can about 5,000 to about 1,500,000, or about 10,000 to about also be employed. 10 550,000, or about 100,000 to about 550,000, or about 100,000 to about 400,000. The molecular weight distribution (the ratio The halogen-free flame retardant material can be blended (Mw/Mn) of the weight-average molecular weight (Mw) to into any resin-containing component, for example, compo the number-average molecular weight (Mn)) can be about 10 nents used for computers, cellular phones, personal digital or less, or about 5 or less, or about 2 or less. The Mw of the assistants, and the like. The material is especially useful for 15 polymer can be measured by gel permeation chromatography use in components that reside near a heat source, such as (GPC) and determined as a polystyrene-reduced value. board materials and enclosures, for example, the casing of a The HF flame retardant resin composition can be an adhe personal or laptop computer. In some embodiments, the resin sive resin composition, which may include a combination of composition has a melt flow index (ASTM D-1238) of 0.2 to two or more resin compounds having the same or differing 30 g/10 min, or 0.5 to 20 g/10 min. The strength of the molecular weights and degrees of functionality. Two or more resulting composition can be enhanced in some embodiments resins, having the same or different functionality and molecu by employing a resin that has a melt index of about 0.2 to lar weights can be advantageously combined in a formulation about 10.0 g/10 min. that results in a cured resin having a high Tg, and low Dk. In one embodiment, a single olefin resin, a combination of The resins used in adhesive resin compositions can be heat two or more kinds of olefin resins, or a combination of an 25 activated and the adhesive resin compositions can have a olefin resinas a majoringredient and one or two or more kinds viscosity range from about 900 to 2000 centipoise, or about of rubbers can be used for the resin composition. When being 1200 to about 1700 centipoise. The viscosity can be modified used in combination, the olefin resin and rubber may be by altering the Solids content or the resin ingredients used in combined prior to addition of a flame retardant additive, or the the adhesive resin composition. 30 Examples of other useful resin components include bistri flame retardant additive can be combined with major ingre azine resins, phenoxy resins, bis-phenol epoxy resins, phe dient, followed by addition of the minor component resin or nolic novolac resins, epoxidized phenolic novolac resins, ure rubber. thane resins, polyvinyl acetate resins, and any other resins The types of rubber used can include ethylene-propylene that can be useful in adhesive resin compositions. Further based rubbers, butadiene-based rubbers, isoprene-based rub 35 examples of useful resin and resin ingredients are described in bers, natural rubbers, nitrile rubbers, isobutylene rubbers, and U.S. Pat. Nos. 5,674,611; 5,629,098; and 5,874,009, which the like. Ethylene-propylene-based rubbers include random are incorporated herein by reference. copolymers mainly composed of ethylene and propylene, or The resin compositions typically will include about 1 wt.% random copolymers mainly composed of ethylene, propy to 40 wt.%, or about 5 wt.% to 30 wt.%, of a halogen-free lene, and a diene monomer as the third component, Such as 40 flame retardant additive and from about 60 wt.% to 95 wt.% dicyclopentadiene or ethylidene norbornene, and the like. of one or more resin compounds. The adhesive resin compo Butadiene-based rubbers are typically copolymers com sitions can also include about 10 wt.% to about 20 wt.% of prising butadiene as the major ingredient, which include Sty one or more halogen-free flame retardant additives, or about rene-butadiene block copolymers and hydrogenated or par 12 wt.% to about 17 wt.% of a halogen-free flame retardant tially hydrogenated derivatives thereof. Such as styrene 45 additive, with the remainder being one or more resin com ethylene-butadiene-styrene copolymers, 1.2-polybutadiene, pounds. maleic anhydride-modified styrene-ethylene-butadiene-sty The mechanical and electrical properties of the resin com rene copolymers, modified butadiene rubbers having a core positions upon cure can be substantially controlled by choice shell structure, and the like. of the molecular weight of ingredients used in the resin com Isoprene-based rubbers are typically copolymers compris 50 position. When certain oxygen containing resins are used, for ing isoprene as the major ingredient, which include styrene example, a phenoxy resin, the molecular weight can be about isoprene block copolymers and hydrogenated or partially 8,000 to about 60,000, for example, about 20,000. hydrogenated derivatives thereof. Such as styrene-ethylene The resin compositions may include other ingredients and isoprene-styrene copolymers, maleic anhydride-modified additives known to those of ordinary skill in the art to be styrene-ethylene-isoprene-styrene copolymers, modified iso 55 useful in a resin composition, for example, adhesive resin prene rubbers having a core-shell structure, and the like. compositions. The resin compositions can be particularly In some embodiments, the polymer component or compo useful in preparing resin coated conductive foils, cores, and nents of the flame retardant resin compositions described other Substrates and laminates, for example, those used in the hereincan have molecular weights of greater than about 4500. manufacture of printed circuitboards. The resin compositions For example, one or more of the polymer components can 60 can be used in the manufacture of resin coated conductive have a weight average molecular weight of 10,000 to 250, foils and, in particular, resin coated copper foils. Resin coated 000. The polymers may optionally contain 5 to 60 mol% of copper foils can be manufactured by applying a layer of resin carboxyl groups or carboxylic anhydride groups. The poly to one surface of a two surface conductive foil. The thickness mer component or components can include an epoxy resin, a of resin applied to the foil Surface produces a cured resin maleimide resin, an acrylic resin, a methacrylic resin, a dial 65 thickness of about 20 to about 100 microns. The resin can also lylphthalate resin, a triazine resin, an alicyclic olefin polymer, be applied in a layer having a cured thickness of about 20 to an aromatic polyether polymer, a benzocyclobutene polymer, about 50 microns. After coating with an adhesive resin, the US 8,871,843 B2 10 resin coated copper can be partially cured or b-staged. A 4,4'-(p-phenylenediisopropylidene)dianiline, 2,2'-bis(4-(4- second layer of resin may be applied to the surface of the aminophenoxy)phenylpropane, and 1.3.5-benzenetriamine. b-staged resin layer. If a second layer of resin is applied, the Examples of compounds having two or more hydrazide second layer of resin can be b-staged during which time the groups include isophthalic acid dihydrazide, terephthalic acid first layer typically becomes essentially fully cured. The final dihydrazide, 2,6-naphthalenedicarboxylic acid dihydrazide, product can be, for example, an adhesive resin coated con maleic acid dihydrazide, itaconic acid dihydrazide, trimellitic ductive coated metal foil that is useful in standard printed acid dihydrazide, 1,3,5-benzenetri-carboxylic acid dihy circuit board manufacturing techniques. drazide, and pyromellitic acid dihydrazide. In one embodiment, the HF flame retardant resin compo Examples of aziridine compounds include tris-2,4,6-(1- 10 aziridinyl)-1,3,5-triazine, tris 1-(2-methyl)aziridinylphos sition includes a resin composition that includes a thermo phinoxide, and hexa1-(2-methyl)aziridinyltriphosphatriaz plastic resin that includes (a) a block copolymer made up of at 1C. least two polymer blocks that include a vinyl aromatic com Examples of the peroxide include known organic peroX pound and at least one polymer block that includes a conju ides such as ketone peroxide, peroxyketal, hydroperoxide, gated diene compound and/or a hydrogenated block copoly 15 diallylperoxide, diacylperoxide, peroxy ester, and peroxy mer obtained by hydrogenating the block copolymer, a dicarbonate. nonaromatic-series softening agent for rubber, an ethylene Polyepoxy compounds, particularly bisphenol A epoxy C-olefin copolymer; a polypropylene resin; and one or more compounds, such as bisphenol A bis(propylene glycol gly flame retardant additives described below. cidyl ether) ether, are desirable various due to their moderate Curing Agents. The resin of the flame retardant composi reactivity with numerous resins and their capability of pro tion can include a curing agent, for example, during prepara ducing composite resin molded articles that can be easily tion. In a resin that is to be crosslinked, the curing agent is not melted, processed, and laminated. particularly limited insofar as the curing agent can crosslink The amount of curing agent used can be about 1 to about the resin by heating, irradiation, or other initiative process. In 100 parts by weight, or about 5 to about 80 parts by weight, for Some embodiments, the curing agent is a compound that can 25 example, about 10 to about 50 parts by weight, for 100 parts form a crosslinking structure by reacting with carboxyl by weight of the total amount of resin used in the HF flame groups of a resin. retardant resin composition. Examples of curing agents include a polyepoxy com Curing Accelerators. A curable resin composition can fur pound, a compound having two or more isocyanate groups, a ther include a curing accelerator. A curing accelerator can polyamine compound, a compound having two or more 30 facilitate obtaining a cured product having heat resistance. hydrazide groups, an aziridine compound, a basic metal For example, when a polyepoxy compound is used as the oxide, an organic metal halide, and the like. These curing curing agent, a curing accelerator Such as a tertiary amine agents may be used either individually or in combinations of compound or a trifluoroboron complex can be Suitably used. two or more. A peroxide such as dicumyl peroxide, octanoyl A tertiary amine compound is advantageous to certain peroxide, m-chloroperbenzoic acid, or peracetic acid can also 35 embodiments due to its ability to promote compositions hav be used as a curing agent. ing significant heat resistance and chemical resistance. Examples of polyepoxy compounds include compounds Examples of tertiary amine compounds include chain-like having two or more epoxy groups in a molecule, for example, tertiary amine compounds such as benzylmethylamine, tri glycidyl ether epoxy compounds such as a phenol novolak ethanolamine, triethylamine, tributylamine, tribenzylamine, epoxy compound, a cresol novolak epoxy compound, a cresol 40 and dimethylformamide; nitrogen-containing heterocyclic epoxy compound, a bisphenol A epoxy compound, a bisphe compounds such as pyrazoles, pyridines, pyrazines, pyrim nol F epoxy compound, a brominated bisphenol A epoxy idines, indazoles, quinolines, isoquinolines, imidazoles, and compound, a brominated bisphenol F epoxy compound, and triazoles. a hydrogenated bisphenol A epoxy compound; and polyva Examples of the substituted imidazole compound include lent epoxy compounds Such as an alicyclic epoxy compound, 45 alkyl-substituted imidazole compounds such as 2-ethylimi a glycidyl ester epoxy compound, a glycidyl amine epoxy dazole, 2-ethyl-4-methylimidazole, bis-2-ethyl-4-meth compound, and an isocyanurate epoxy compound. ylimidazole, 1-methyl-2-ethylimidazole, 2-isopropyl imida Examples of compounds having two or more isocyanate Zole, 2,4-dimethylimidazole, and 2-heptadecylimidazole; groups include diisocyanates and triisocyanates having 6 to and imidazole compounds Substituted with a hydrocarbon 24 carbonatoms. Examples of the diisocyanates include 2,4- 50 group having a cyclic structure such as an aryl group or an tolylene-diisocyanate, 2,6-tolylenediisocyanate, 4,4'-diphe aralkyl group. Such as 2-phenylimidazole, 1-benzyl-2-meth nylmethanediisocyanate, hexamethylene-diisocyanate, and ylimidazole, 1-benzyl-2-ethylimidazole, benzimidazole, p-phenylenediisocyanate. Examples of the triisocyanates 2-ethyl-4-methyl-1-(2-cyanoethyl)imidazole, 2-ethyl-4-me include 1.3.6-hexamethylenetriisocyanate, 1.6.11-undecan thyl-1-2'-(3".5"-diaminotriazinyl)ethyl)imidazole, and etriisocyanate, and bicycloheptanetriisocyanate. 55 1-benzyl-2-phenylimidazole. These curing accelerators may Examples of polyamine compounds include aliphatic be used either individually or in combination of two or more. polyamine compounds having 4 to 30 carbon atoms and two The amount of curing accelerator can be determined or more amino groups, aromatic polyamine compounds hav according to the needs of the application. Amounts typically ing two or more amino groups, and the like. In some embodi are about 0.001 to 30 parts by weight, about 0.01 to 10 parts ments, compounds having a non-conjugated nitrogen-carbon 60 by weight, or about 0.03 to 5 parts by weight, for 100 parts by double bond Such as a guanidine compound can be excluded. weight of the total amount of resin in the composition. Examples of aliphatic polyamine compounds include hex Fillers. The resin composition can include one or more amethylenediamine and N,N'-dicinnamilidene-1,6-hex fillers. Fillers can provide the composite resin with several anediamine. desired performance characteristics such as tensile strength, Examples of aromatic polyamine compounds include 4,4'- 65 hardness, and/or weight. Examples of fillers include carbon methylenedianiline, m-phenylenediamine, 4,4'-diamino black, white carbon, silica, Zirconium silicate, alumina, diphenyl ether, 4'-(m-phenylenediisopropylidene)dianiline, hydrated alumina, aluminum trihydrate, hydrated magne US 8,871,843 B2 11 12 sium, barium sulfate, barium titanate, titanium oxide, anti gas, and are rapidly hydrolyzed by water to form ammonia. mony trioxide, magnesium oxide, molybdenum oxide, tin Examples of nitrides that can be used as flame retardant oxide, Zinc oxide, talc, mica, glass beads, hollow glass balls, additives include the alkali metal nitrides, such as lithium clay, silicone oil, quartz, barium carbonate, calcium carbon nitride (LiN), and the alkaline earth metal nitrides, such as ate, and/or magnesium carbonate. magnesium nitride (Mg,N), beryllium nitride (BeN), and The average particle diameter of inorganic fillers can be calcium nitride (Ca,N). about 0.008 um or more, but is typically less than 2 Lum. In Lithium nitride is readily formed and can be obtained com some embodiments, the diameter is about 0.01 um or more, mercially. NaN and KN have been synthesized by simulta but less than about 1.5um, or 0.02 um or more, but less than neously depositing metal atoms and nitrogen atoms onto a lum. 10 liquid nitrogen cooled sapphire substrate. Both NaN and Each filler is optional, but when present, each can be KN are considered unstable compounds. included in about 0.1 to 30 parts by weight, or about 1 to 15 Borides and Borates. Borides and/or borates can act as parts by weight, to 100 parts by weight of the total resin flame retardant additives when combined with a polymer or component. In some embodiments, more than one type of resin. The flame retardant action of the boride or borate is filler can be included in the HF flame retardant resin compo 15 similar nitrides and nitrites. A negatively-charged boride or sition. In some embodiments, about 0.5 to 5 parts by weight of borate species results upon decomposition to yield a far less each optional filler is included in the resin composition. toxic acid after it scavenges high energy protonions, in com Flame Retardant Additives. parison to halogenated flame retardants. For example, upon The flame retardant additives described below, when com heating near the Surface of a Solid resin material, the boron bined with a resin, can result in significantly lower toxicity as containing compounds can form an acid, Such as boric acid, flame retardants compared to halogen-containing flame retar which chars carbon compounds at the Surface of the resin dants, such as chlorine and bromine containing compositions. material, causing gaseous bubbles to form, which then harden The flame retardant additives can interfere with the burning within the charred Surface of the resin, producing a fire process by promoting various physical processes. Such pro resistant barrier on the surface. cesses can include the release of water or non-flammable 25 Examples of borates that can be used as flame retardant gases, which dilute the gases feeding flames; absorption of additives include the alkali metal borates, such as sodium heat energy (in these gas-release reactions), thus cooling the metaborate (NaBO), sodium tetraborate (NaBO7), and fire; and/or production of a non-flammable and resistant layer NaBs or NaB (also known as NaBs), and the alkaline on the Surface of material. Such decomposition reactions can earth metal borates, such as calcium aluminum triborate act to form a glassy protective layer on the materials surface, 30 (CaAlBO7; johachidolite), and the inexpensive magnesium and/or release of an acid that can cause charring of the mate diboride (MgB). rial, thereby reducing the release of flammable gasses. A number of polymeric borate ions are known in anhy These additives can be used in relatively large concentra drous compounds, which are made by reacting B(OH) or tions, and/or in combination with other types of flame retar BO with metal oxides. Examples include diborate dants. Specific applications of these additives, for example, 35 (B.O."), e.g., in Mg2BOs (suanite); triborate (B.O.), within organic coatings, can enable high concentrations to be e.g., in CaAlBO, (johachidolite); tetraborate (B.O.), e.g., added to resins without modifying their performance proper in e.g. LiBO; and metaborates containing the linear ties. BO, with three coordinate boron, such as in LiBO or The flame retardant resin compositions described herein CaBO. Common borate salts include sodium metaborate include one or more flame retardant additives described 40 (NaBO), and sodium tetraborate (NaBO), which is usu below. The flame retardant additive can be a nitrite, a nitride, ally encountered as borax, the so-called decahydrate, and aborate, a silicide, a silicate, an antioxidant compound, and/ actually contains the hydroxoborate ion, BO(OH), and is or combinations thereof. Examples of nitrides include alkali often formulated NaBO(OH)4.8HO. Various other metal nitrides and alkaline earth nitride. Examples of borates known forms of borate can be used as flame retardant addi include alkali metal borates and alkaline earth borates. 45 tives. Such as disodium octaborate tetrahydrate. Examples of silicides include alkali metal silicides and alka Silicides. Silicides are compounds that have silicon bonded line earth silicides. Examples of silicates include alkali metal to more electropositive elements. Silicides are structurally silicates and alkaline earth silicates. Examples of antioxi closer to borides than to carbides. The chemical bonds in dants include compounds Such as amino acids (e.g., glu silicides range from conductive metal-like structures to cova tathione) and alkali or alkaline earth salts thereof, polyphe 50 lent or ionic. Silicides of all non-transition metals, with nols, carotenoids, tocotrienols, ascorbic acid and alkali or exception of beryllium, have been described. alkaline earth salts thereof, lipoic acid and alkali or alkaline Examples of silicides include the electrically nonconduc earth salts thereof, and/or combinations thereof. tive magnesium silicide (MgSi) and calcium silicide Nitrites. Nitrites (NO) can be used as flame retardant (Ca,Si), and Si tetrahedra such as KSi, Rb Si, and Cs.Si. additives by incorporating the nitrites into a resin. When 55 Silicides can also be in the form of Si, chains, such as CaSi exposed to Sufficient heat, nitrite infused resins can decom chains, and corrugated hexagonal Si layers, for example, pose to release nitrous oxide (a non-flammable gas). Alkali CaSi. Group 1 and 2 silicides, e.g., Na2Si and Ca2Si, react metal ions or alkaline earth metal ions can Scavenge nega with water to yield hydrogen and/or silanes. Additional tively-charged high energy ions. Examples of nitrites that can examples of alkali metal silicides and alkaline earth metal be used as flame retardant additives include the alkali metal 60 silicides include Sodium silicide (NaSi) and magnesium sili nitrites, such as lithium nitrite (LiNO), sodium nitrite cide. Magnesium silicide is dark blue or slightly purple in (NaNO), and potassium nitrite (KNO), and the alkaline color. Silicon dioxide forms magnesium silicide when heated earth metal nitrites, such as magnesium nitrite (Mg(NO)) with magnesium. Magnesium silicide can also be formed by and calcium nitrite (Ca(NO)). a reaction between magnesium hydride and silicon with the Nitrides. Nitrides can act as flame retardant additives when 65 evolution of hydrogen gas attemperatures above 250° C. combined with a polymer or resin. For example, lithium Silicates. Silicate are compounds containing ions in which nitride and the alkaline earth nitrides deprotonate hydrogen one or more central silicon atoms are Surrounded by elec US 8,871,843 B2 13 14 tronegative ligands. Silicate species most often are silicon herein. Examples of Such inorganic flame retardants include with oxygen as the ligand. Silica, or silicon dioxide, SiO, can aluminum hydroxide, magnesium hydroxide, calcium be considered a silicate, although it is the special case with no hydroxide, or a combination thereof, where the particles have negative charge and no need for counter-ions. Silica is found an average size (diameter) of about 0.1 to about 10 um. Such in nature as the mineral quartz, and its polymorphs. Silicon inorganic compounds may be added in an amount of 1% to may adopt octahedral coordination by 6 oxygens, for 50% by weight, based on the total weight of the composition, example, in the hexahydroxysilicate anion, Si(OH)', as to impart flame resistant effects to the resin. For example, found in the mineral thaumasite (CaSiOCO)(SO4)(OH)12 aluminum hydroxide, magnesium hydroxide, calcium (HO)). hydroxide, or a combination thereof, can be included in about Other examples of silicates include alkali metal silicates 10 1%, about 2%, about 5%, about 10%, about 15%, about 20%, and alkaline earth metal silicates. Such as the metals in com about 30%, about 40%, or about 50% by weight, based on the bination with silicate ions, such as nesosilicates (SiO4), total weight of the composition. e.g., olivine; sorosilicates (SiO,I), e.g., epidote, cyclosili Other useful halogen-free fire retardant optional additives cates (SiO”), e.g., the tourmaline group; inosilicates include melamine cyanurate, phosphoric acid, 1,3-phenyle (SiOs,”), e.g., the pyroxene group; inosilicates 15 netetraphenyl ester, di-polyoxy-ethylene, hydroxymeth (SiO, I"), e.g., the amphibole group; phyllosilicates ylphosphonate, and mixtures thereof. The particle size of (Si2Osl”), e.g., micas and clays; and tectosilicates (Al optional additives such as melamine cyanurate can range SiO2e), e.g., quartz, feldspars, and/or Zeolites. Tecto from about 1 to about 20 microns. Typical melamine cyanu silicates can have additional cations when some of the silicon rate particle sizes are less than about 12 microns. Melamine is replaced by a lower-charge cation Such as aluminum. This cyanurate particle sizes of less than 4 microns can help mini Substitution can also take place in other types of silicates. mize surface defects and resin wet-out problems. Synthetic silicates also can be used in the flame retardant Other optional components include lubricants such as min compositions described herein. Some are called “hydrated eral oil or paraffin oil, to enhance the stability of the compo silicic acid' or “wet silica”. The synthetic silicate can have sition, for example, during processing. The composition may any crystalline structure, including somewhat random net 25 include a titanate or silane coupling agent to enhance the works of Si-O. commonly referred to as “amorphous adhesion of a filler to the resin matrix. The composition may silica”. The synthetic silicate is typically 40% to 70% by also contain an organic or inorganic pigment or dye. Such as weight SiO, and 5% to 45% by weight each of MgO and/or carbon black, an azo type pigment, cyanine blue, cyanine CaO as secondary components. In one embodiment, a syn green, iron oxide red, or titanium oxide, to add various colors thetic silicate containing 50% to 60% by weight of SiO, and 30 to the resin composition. 12% to 30% by weight of a combination of MgO and CaO, Yet other optional additives include antimony compounds and having an ignition loss of 10 to 30% by weight is used. such as antimony pentoxide, and sodium antimonite; inor Silicides and/or silicates act similarly to nitrites, with the ganic compounds Such as Zinc borate, guanidine Sulfamate, additional ability of any remaining siliconoxide compound in Zirconium salts, molybdenum salts, aluminum borate, and tin the resin that has not been released for high energy ion scav 35 compounds; organometallic compounds such as ferrocene; enging to form a vitreous Substance that can shield the resin and phosphorus-containing compounds such as phosphates, from further flame exposure. aromatic-condensed phosphates, phosphaZene compounds, Antioxidants. Incorporation of antioxidant compounds phosphorus-containing epoxy compounds, reactive phospho Such as amino acids (e.g., glutathione), polyphenols, caro rus compounds, ammonium polyphosphate, melamine phos tenoids, tocotrienols, ascorbic acid, and/or lipoic acid, into 40 phate, melamine salts of polyphosphoric acid, melam salts of resins can Scavenge high energy ions that may be released by polyphosphoric acid, melem salts of polyphosphoric acid, burning the resin. The antioxidants can be included in a resin complex melamine-melam-melem salts of polyphosphoric alone, or in combination with other flame retardant additives acid, red phosphorus, and phosphaZene compounds. Such described above. components can promoting and/or provide heat resistance, Hydrates of the inorganic additives described above can 45 moisture resistance, and flame retardance. also be employed in resins. In the presence of heat, the Each optional additive, when present, can be included in hydrates can decompose to release water. The water, as steam, about 0.1 to 15 parts by weight, to 100 parts by weight of the can form a layer of non-flammable gas near a materials total resin component. In some embodiments, more than one surface, thereby inhibiting flame formation. The reaction to optional additive, e.g., 2, 3, 4, or 5 optional additives, can be release water and/or decomposition of the additive compound 50 included in the HF flame retardant resin composition. In some can be endothermic, thereby cooling the material and slowing embodiments, about 0.5 to 5 parts by weight of each addi the burning process. tional optional additive is included in the resin composition. The amount of the flame retardant additive used in a resin The resin composition can optionally exclude certain composition can be about 10 to about 300 parts by weight, for ingredients, such as one or more optional additives described example, 100 to 250 parts by weight, to 100 parts by weight 55 above, such as phosphorus or phosphorus containing com of the total resin component of the composition. Amounts pounds. The combination of certain flame retardant additives within the aforementioned ranges, at increments of 5 parts by and optional additives, in combination with the exclusion of weight, can also be used, with respect to 100 parts by weight other optional additives can provide a composition with of the total resin component of the composition. excellent mechanical characteristics, fire retardancy, heat Optional Additives. 60 resistance, and flexibility, which also exudes no harmful Although the composition can include a resin, such as a heavy metal compounds, nor does it produces a large amount thermoplastic synthetic resin, and a flame retardant additive of Smoke or corrosive gases when buried or burned. as described above, the flame retardant resin composition Preparation of Flame Retardant Resin Compositions. may also include additional optional components. Inorganic Halogen-free fire-retardant materials secure their fire-re flame retardants, other than the flame retardant additives 65 tardancy by mixing a halogen-free fire-retardant additive in a described above, can optionally be added to resins to provide resin. The halogen-free flame retardant synthetic resin com additional variations of the flame retardant resins described position can be prepared by using a master batch that includes US 8,871,843 B2 15 16 a polymer, such as a thermoplastic synthetic resin, a flame parts of the resin. In one embodiment, about 0.5-1 part by retardant additive as described herein, and other optional weight per 100 parts of the resin can be used. additives, or by mixing these components each in Such an In the single step operation, the resin or resins, the flame amount So as to provide its end-use concentration, followed retardant additive, a filler and optionally other ingredients can by kneading the resulting mixture by ordinary means, such as be charged at the desired ratio to a Farrell Continuous Mixer using a single-screw type extruder, twin-screw type extruder, (FCM), a transfer type extruder-mixer that allows efficient mastication of the blend at a desired temperature. The blend roll mill, or Banbury mixer. Flame retardant additives, such as ing apparatus can be pretreated to reduce the time necessary borates, nitrides, silicides, and/or silicates, may be prelimi to reach the processing temperature range. The same opera narily added to the other components prior to, during, or after tion can also be run in a Banbury-type mixer. mixing the resin and other optional components. 10 The blend is then held at the processing temperature while In some embodiments, one or more flame retardant addi continuing the mixing. During processing, a stabilizer system tives as described herein can be either simply mixed into can be contacted with the blend and processing can be con plastics and then held in the material when the plastic sets, or tinued for a short time, usually for about one minute or more, when reactive to the plastic or optionally added crosslinking in order to thoroughly incorporate the stabilizer in the blend. agents, the flame retardant additive can chemically bind into 15 In a multi-step process, the resin or resins and the flame the plastic molecules at polymerization. A selection between retardant additive can be charged to a suitable apparatus simply mixing and chemically binding can depend on the wherein flame retardant additive masterbatching takes place. properties desired or required of the flame retardant resin Thereafter, the flame retardant masterbatch can be blended composition, in terms of finished product performance, with the resins at desirable ratios, optionally with other com means of processing (e.g., melting, extrusion, and/or mold ponents, as desired for the specific composition. ing), and flame retardancy characteristics (e.g., temperature A method for forming a non-halogen flame retardant resin of onset of the charring process). composition includes preblending the components. One-half Evaluation of the composition can be carried out by stan of the total amount of resin, such as polypropylene, can be dard polymer analysis techniques. For example, when a ther placed in an accurate loss and weigh feeder preblender. Pre moplastic resin other than polystyrene or ABS is used, the 25 weighed ingredients other than the resin can be added to the resin, a flame retardant additive, and other additives can be preblender, one-half of each ingredient to each side of the mixed and the obtained mixture can be kneaded in a 75 liter blender. The preblender can be turned on and the resin is mixed for about five minutes. Thereafter, the remainder of the Banbury mixer. The mixture can be processed with a mixing resin is added to the preblender and mixed for about an roll to obtain a sheet having a thickness of about 3 mm. This additional ten minutes to thoroughly mix the resin and flame sheet can be reprocessed with a rectangular pelletizer to pro 30 retardant additive system. vide a rectangular pellet having a length of each side of about An extruder resin system can be pelletized or can conduct 3 mm. The HF flame retardant resin composition can also be other processing as necessary. If pelletizing is carried out, a provided in the form of a film or a sheet. The thickness of the pelletizer, such as a pelletizer commercially available from film or sheet can be about 1 to 150 lum, or about 3 to 100 um, Conair, Inc., can be set to, for example, about 44 rpm to form for example, about 5 to 80 um. 35 pellets that have a diameter of, for example, about 0.03125 to This rectangular pellet can be repelletized with a vent type about 0.0625 inches (0.079 and 0.16 cm). Hot, dry air can be 70 Phi extruder at 150° C. to provide a cylindrical pellet. This blown over the pellets prior to packaging to minimize water cylindrical pellet can be used as a sample for analysis, or it can contact and absorption. be combined with other pellets to parts, components, or other The flame retardant resin composition can be reheated to a forms for various electronic applications. The cylindrical pel 40 temperature of about 410° F (about 210°C.) for molding let can be examined for oxygen index, for example, according various components such as casings or other Suitable struc to JIS K-7201. The pellet can also be molded into a sheet tures. The thickness of casings can be, for example, about having a thickness of 200 um with a T-die sheet molding 0.03125 to about 0.125 inches (0.079 and 0.32 cm). machine to determine the combustion rate of the sheet with a Devices and Apparatuses. flammability tester, for example, according to FMVSS-302 45 The flame retardant materials described herein can be used in devices and apparatuses that include plastic materials, standards. especially those that include electrical components or require When polystyrene or ABS is used as a thermoplastic syn flame resistance. Examples include molded parts, wire coat thetic resin, the resulting composition can be molded with an ings, circuit board Substrates, or parts for cellular phones, injection machine of about 3.5 ounces into a test bar, for PDAs (portable information terminals), mobile videophones, example, according to the vertical flame test of UL-94. The 50 personal computers, electronic notebooks, servers, routers, test bar can be further molded into a test piece having a LCD projectors, engineering workstations (EWS), pagers, thickness of approximately /8 inch. This test piece can be word processors, televisions, video recorders, calculators, a used as a sample for the Vertical flame test. car navigation systems, POS terminals, or touch panel The processability of the resin compositions described equipped devices. The flame retardant materials can also be herein can be evaluated by subjecting samples of the blend to 55 used as coverings or coatings for materials such as wiring shaping operations such as injection molding or compression materials, electric cables, optical fibers, and the like. molding. For satisfactory injection molding, the material The resulting composite resin molded articles can have should form in the mold a homogeneous article of uniform excellent flame retardancy, electric insulation properties, and strength. The flow viscosity characteristics of such blends are crack resistance, and can generate only a very Small amount adequate to insure filling the mold properly under the oper 60 of toxic Substances during incineration. Laminate and multi ating conditions. In processing the resin, a lubricant can be layer circuit boards can have a low thermal expansion and a included, for example, to improve the molding quality of the high modulus of elasticity. resin composition. In some embodiments, the lubricant can FIG.1 illustrates a representation of computing system 100 be Akzo Armeen(R) 18D surfactant or VanfreRVam process including an input device in the form of a keyboard 108, a ing aid. Any known lubricant conventionally used in plastics 65 device 118 that can provide input to the computing system or processing can also be used. A lubricant can be used in store information Such as an external hard drive, phone, or amounts varying from about 0.1-3 parts by weight per 100 similar device, and a mouse 124. For the purposes of this US 8,871,843 B2 17 18 specification, the term "computing system’ includes a system Nitrides. The nitride flame retardant can be lithium nitride, that uses one or more processors, microcontrollers and/or magnesium nitride (Mg,N), beryllium nitride (BeN), or digital signal processors and that has the capability of running calcium nitride (Ca,N). a “program.” As used herein, the term “program” refers to a Borides and Borates. The boride or borate flame retardant set of executable machine code instructions, and as used can be sodium metaborate (NaBO), sodium tetraborate herein, includes user-level applications as well as system (NaBO), NaBas, NaBoNaBs, calcium aluminum directed applications or daemons, including operating system triborate (CaAlBO7; johachidolite), magnesium diboride and driver applications. Computing systems include commu (MgB), MgBOs (suanite): CaAlBO, (johachidolite); nication and electronic devices, such as mobile phones (cel LiBO: LiBO, CaBO, sodium metaborate (NaBO), lular or digital), music and multi-media players, and Personal 10 Digital Assistants (PDA); as well as computers, or “comput sodium tetraborate (NaBO7), NaBO(OH)4.8H2O, or ing devices of all forms (desktops, tablets, laptops, servers, disodium octaborate tetrahydrate. palmtops, workstations, etc.); and further include the periph Silicides. The silicide flame retardant can be MgSi, CaSi, eral devices that are used to control and interface with the KSi, Rba.Si. Cs. Si, CaSi, Na-Si, CaSi, sodium silicide remainder of the computing system. 15 (NaSi), or magnesium silicide (MgSi). Many configurations of peripheral components can be Silicates. The silicate flame retardant can be silica, silicon employed with Such computing systems, as will be recog dioxide (SiO), thaumasite (CaSiOCO)(SO4)(OH)12 nized by those skilled in the art. Keyboard 108 can be of a (HO)), olivine; or epidote. configuration well-known in the industry, having plastic keys Antioxidants. The antioxidant flame retardant can be glu and often additional components formed of plastics, includ tathione, Vitamin A, vitamin E, ascorbic acid, or lipoic acid. ing attachment cables and port connectors. As will be appar ent to one of skill in the art, the methods and apparatus synthetic resin 50-100 parts described are applicable both to much simpler and to more filler 20-150 parts complicated devices and computing systems. Any component flame retardant additive 25-250 parts that includes plastic or a resin can include a flame retardant 25 pigment 3-30 parts resin composition as described herein. In some embodiments, the input device can be a mouse, a Total 98-530 parts touch screen, a keypad of a mobile communications device, or another type of input interface, etc. Keyboard 108 can The components of Example 1 may be present at any 5 part includes a plurality of keys (e.g., 112 and 114 configured to 30 increment from endpoint to endpoint of the recited ranges. In detect user inputs, and to communicate those user inputs to Some embodiments, the filler and/or pigment components can computing device 102 through a wired (or in some cases, a be omitted entirely. wireless) connection 120. Mouse 124 can be configured to detect user inputs, and to communicate those user inputs to Examples 2-27 computing device 102 through a wired (or, again, in some 35 cases, a wireless) connection 122. Device 118 can be config Flame-Retardant Resin Compositions ured to detect user inputs or to allow for access of stored information, and to communicate those user inputs or the For examples 2-27, the flame retardant additive can be an information to computing device 102 through a wired con alkali or alkaline earth nitride; an alkali or alkaline earth nection 116. The input can be communicated to the user via 40 monitor 104. Computing device 102 can receive power nitrite; an alkali or alkaline earthborate; an alkali or alkaline through a power connection cord 106. earth silicide; an alkali and alkaline earth silicate; or an anti The following Examples are intended to illustrate the oxidant compound, as described for Example 1. above invention and should not be construed as to narrow its Example 2 scope. One skilled in the art will readily recognize that the 45 Examples Suggest many other ways in which the invention could be practiced. It should be understood that numerous variations and modifications may be made while remaining low-density polyethylene (e.g., YUKARON HE-30 mfl. by 60 parts within the scope of the invention. The recited amounts are Mitsubishi Petrochemical Co., Ltd., MI: 0.3) parts by weight, unless otherwise indicated. 50 flame retardant additive 40 parts synthetic calcium silicate (e.g., SILMOS-T mfcd. by 3 parts EXAMPLES Shiraishi Industrial Co., Ltd., SiO2 content: 60%) Total 103 parts Example 1 55 Flame-Retardant Resin Compositions Example 3 The flame retardant additive can be an alkali or alkaline earth nitride; an alkali or alkaline earth nitrite; an alkali or alkaline earth borate; an alkali or alkaline earth silicide; an 60 low-density polyethylene (same component as in 55 parts alkali and alkaline earth silicate; or an antioxidant compound. Example 2) For example, the flame retardant additive can be one or more flame retardant additive 45 parts of the following additives. synthetic calcium silicate (same component as in 3 parts Nitrites. The nitrite flame retardant can be lithium nitrite Example 2) (LiNO), sodium nitrite (NaNO), potassium nitrite (KNO), 65 Total 103 parts magnesium nitrite (Mg(NO)), or calcium nitrite (Ca(NO)). US 8,871,843 B2 19 20 Example 4 -continued synthetic calcium silicate (SOLEX CM, the same as in 3 parts Example 7) low-density polyethylene (same component as in 50 parts 5 Example 2) Total 103 parts flame retardant additive 50 parts synthetic calcium silicate (same component as in 1.5 parts Example 2) Example 10 Total 101.5 parts 10

low-density polyethylene (YUKARON HZ-30, same as that 50 parts Example 5 in Example 2) flame retardant additive 50 parts 15 synthetic calcium silicate (SOLEX CM, same as in 3 parts Example 7) low-density polyethylene (same component as in 50 parts Example 2) Total 103 parts flame retardant additive 50 parts synthetic calcium silicate (same component as in 3 parts Example 2) Example 11 Total 103 parts

low-density polyethylene (same component as in 50 parts Example 6 25 Example 2) flame retardant additive synthetic calcium silicate (same component as in Example 2) straight-chain low-density polyethylene (e.g., ULTZEX 50 parts 352OF mfcd. by Mitsui Petrochemical Industries, Total 107 Ltd. MI: 2.1) 30 flame retardant additive 50 parts Synthetic silicate (same component as in Example 2) 3 parts Example 12 Total 103 parts

35 low-density polyethylene (same component as in 50 parts Example 7 Example 2) flame retardant additive 50 parts synthetic calcium silicate (same component as in 10 parts 40 Example 2) high-density polyethylene (HIZEX 3300F mfl. by Mitsui 50 parts Petrochemical Industries, Ltd., MI: 0.9) Total 110 flame retardant additive 50 parts synthetic calcium silicate (e.g., SOLEX CM mfcd. by 3.0 3 parts parts Tokuyama Soda Co., Ltd., SiO2 content: 57%) Example 13 Total 103 parts 45

Example 8 polystyrene (e.g., STYRON 470 mfcd. by Asahi Chemical 50 parts Industry Co., Ltd, MI: 4.0) 50 flame retardant additive 50 parts synthetic calcium silicate (SILMOS-T, same as in 3 parts Example 2) ethylene-vinyl acetate copolymer (Evatate H 1011 mfl. by 50 parts Sumitomo Chemical Co., Ltd., vinyl acetate content: 15%) Total 103 parts flame retardant additive 50 parts synthetic calcium silicate (SOLEX CM, the same as in 3 parts 55 Example 7) Example 14 Total 103 parts

Example 9 60 ABS (e.g., DENKA OF mfcd. by Denki Kagaku Kogyo 50 parts K.K.) flame retardant additive 50 parts synthetic calcium silicate (SILMOS-T, same as in 3 parts Example 2) polypropylene (e.g., JHG mfl. by Mitsui Toatsu Chemicals, 50 parts Inc., MI: 4.0) 65 Total 103 parts flame retardant additive 50 parts US 8,871,843 B2 21 22 Example 15 Example 21 low-density polyethylene (e.g., YUKARON HE-30 mfcd. by 60 parts ethylene-vinyl acetate copolymer (Evatate H 1011 mfl. by 50 parts Mitsubishi Petrochemical Co., Ltd., MI: 0.3) Sumitomo Chemical Co., Ltd., vinyl acetate content: 15%) magnesium hydroxide (e.g., KISUMA 5B mfl. by Kyowa 40 parts magnesium hydroxide (same component as in Example 15) 50 parts Chemicals Co., Ltd., average particle size:0.8 m) synthetic calcium silicate (SOLEX CM, the same as in 3 parts synthetic calcium silicate (e.g., SILMOS-T mfcd. by 3 parts Example 7) Shiraishi Industrial Co., Ltd., SiO, content: 60%) flame retardant additive 30 parts flame retardant additive 30 parts Total 103 parts Total 103 parts 10

Example 16 Example 22 polypropylene (e.g., JHG mfl. by Mitsui Toatsu Chemicals, 50 parts low-density polyethylene (same component as in 55 parts 15 Inc., MI: 4.0) Example 2) magnesium hydroxide (same component as in Example 15) 50 parts magnesium hydroxide (same component as in Example 15) 45 parts synthetic calcium silicate (SOLEX CM, the same as in 3 parts synthetic calcium silicate (same component as in 3 parts Example 7) Example 2) flame retardant additive 30 parts flame retardant additive 30 parts flame retardant additive 30 parts Total 103 parts Total 103 parts Example 23 Example 17 25 low-density polyethylene (YUKARON HZ-30, same as 50 parts low-density polyethylene (same component as in 50 parts that in Example 2) Example 2) aluminum hydroxide (HIGILITE H-42M mfcd. by Showa 50 parts magnesium hydroxide (same component as in Example 15) 50 parts Light Metal Co., Ltd., average particle size:0.8 m) synthetic calcium silicate (SOLEX CM, same as in 3 parts synthetic calcium silicate (same component as in 1.5 parts Example 7) Example 2) 30 flame retardant additive 30 parts flame retardant additive 30 parts Total 101.5 parts Total 103 parts

Example 18 35 Example 24 low-density polyethylene (same component as in 50 parts low-density polyethylene (same component as in 50 parts Example 2) Example 2) magnesium hydroxide (same component as in Example 15) 50 parts magnesium hydroxide (same component as in Example 15) 50 parts synthetic calcium silicate (same component as in 3 parts 40 synthetic calcium silicate (same component as in 7 parts Example 2) Example 2) flame retardant additive 30 parts flame retardant additive 30 parts Total 103 parts Total 107 parts

45 Example 19 Example 25 straight-chain low-density polyethylene (e.g., ULTZEX 50 parts low-density polyethylene (same component as in 50 parts 352OF mfcd. by Mitsui Petrochemical Industries, Ltd. 50 Example 2) MI: 2.1) aluminum hydroxide (e.g., HIGILITE H-42M mfcd. by 50 parts magnesium hydroxide (same component as in Example 15) 50 parts Showa Light Metal Co., Ltd., average particle size synthetic silicate (same component as in Example 2) 3 parts of 0.8 m) flame retardant additive 30 parts synthetic calcium silicate (same component as in 10 parts Example 2) Total 103 parts flame retardant additive 30 parts 55 Total 110 parts Example 20 high-density polyethylene (HIZEX 3300F mfl. by Mitsui 50 parts Example 26 Petrochemical Industries, Ltd., MI: 0.9) 60 magnesium hydroxide (same component as in Example 15) 50 parts synthetic calcium silicate (e.g., SOLEX CM mfcd. by 3.0 3 parts parts Tokuyama Soda Co., Ltd., SiO2 content: 57%) flame retardant additive 30 parts polystyrene (e.g., STYRON 470 mfcd. by Asahi Chemical 50 parts Industry Co., Ltd, MI: 4.0) Total 103 parts 65 magnesium hydroxide (KISUMA 5B, the same as in 50 parts Example 15) US 8,871,843 B2 24 -continued 1. The lubricant can be any lubricant described herein, such as montanoic acid-Saponified ester was. synthetic calcium silicate (SILMOS-T, same as in 3 parts Example 2) flame retardant additive 30 parts 5 Example 35 Total 103 parts

Wt. 90 INGREDIENT Net DESIGNATION INGREDIENTNAME Weight 10 ASO007 (BT2110) Bistriazine Resin (Mitsubishi) 39.1 Example 27 A50004 (PKHS-40) Phenoxy resin (40% solids - M.W. 22.4 (a) 20,000) - Used as a flexibilizer? resin ASOO15 (EPON 1031A70) Bis-Phenol-A epoxy resin 1.9 15 981 7Q (EPN 1138MAK80) Epoxidized phenolic novolac resin 13.4 ABS (e.g., DENKA OF mfcd. by Denki Kagaku Kogyo 50 parts A50740 (DER 732) Epoxy resin 3.8 K.K.) Flame retardant additive Halogen-free flame retardant 15.3 magnesium hydroxide (KISUMA 5B, the same as in 50 parts as described for Example 1 Example 15) 97995 (PKHP-200) Solid phenoxy resin (M.W. (a) 3.1 synthetic calcium silicate (SILMOS-T, same as in 3 parts 20,000) Example 2) 2O Z-6040 Silane Surfactant 1.O flame retardant additive 30 parts TOTALS 100 Total 103 parts

In each of Examples 1-27, a second flame retardant addi Example 36 tive can be added at an amount of about 5 parts to about 300 25 parts, or at any 5 part increment in between. A second filler or A halogen free flame retardant resin composition can a third retardant additive of about 1.5 parts to about 40 parts include 0.5 to 15 parts by weight of a flame retardant as each can also be added. Each Example may also include 1-30 described for Example 1: 70 to 30 parts by weight of a ther parts of a dye or pigment component. 30 moplastic synthetic resin; and 30 to 70 parts by weight of an inorganic filler, Such as magnesium hydroxide or aluminum hydroxide having average particle sizes of 0.1 to 10 um. Examples 28-34 Example 36 35 Flame-Retardant Resin Compositions and Molded A halogen free flame retardant resin composition can Parts include (a) 100 parts by weight of a block copolymer made up

Example

28 29 30 31 32 33 34

Block copolymer 100 1OO 100 1OO 1OO 100 1OO Paraffin oil 40 76 15 90 40 70 40 Ethylene-C-olefin 133 81 8O 60 1OO 370 133 copolymer Block polypropylene 33 30 33 Random polypropylene 10 10 18O Peroxide O.66 O.S4 0.4 O.S2 O.9 1.23 O.66 Crosslinking aid 2 1.6 1.2 1.56 2.7 3.7 2 Maleic acid-modified 27 21 16 21 33 46 27 LLDPE Flame retardant 500 40S 331 421 68.0 924 233 additive Antioxidant (optional) 3 2.5 2.2 2.8 4.5 6.1 3 Lubricant 6 5 4.4 S.6 9.0 12.2 6

55 The block copolymer can be any block copolymer of at least two polymer blocks, the polymer blocks including described herein, such as SEPS. The ethylene-C.-olefin a vinyl aromatic polymer and at least one polymer block that copolymer can be any ethylene-C-olefin copolymer described includes a conjugated diene polymer and/or a hydrogenated herein, such as LLDPE. The ethylene-O-olefin copolymerican block copolymer; (b) 30 to 70 parts by weight of a nonaro 60 matic-series softening agent for rubber, (c) 10 to 60 parts by have a density of, for example, about 0.87 g/cm to about weight of a polypropylene-series resin, (d) 50 to 200 parts by 0.925 g/cm. The peroxide can be any peroxide described weight of an ethylene-C-olefin copolymer having a density of herein, for example, dicumyl peroxide or 2,5-dimethyl-2,5- 0.91 g/cm or less; (e) 0.1 to 1.5 parts by weight of an organic di(t-butylperoxy)-hexane. The crosslinking aid can be any peroxide; and 100 to 250 parts by weight of a flame retardant curing agent described herein, such as trimethylene glycol 65 additive, dimethylacrylate. The flame retardant additive can be any wherein the flame retardant additive is one, two, three, four, flame retardant additive, for example, one recited in Example or five of: US 8,871,843 B2 25 26 i) lithium nitrite (LiNO), sodium nitrite (NaNO), potas ally-oriented polyethylene terephthalate (boPET) polyester; sium nitrite (KNO), magnesium nitrite (Mg(NO)), or cal ethylene-C-olefin copolymer, ethylene-vinyl ester copoly cium nitrite (Ca(NO)); mers; ethylene-C.f3-unsaturated carboxylic acid alkyl ester ii) lithium nitride, magnesium nitride (Mg,N), beryllium copolymers; poly(acrylic acid); or polyphenylene sulphone nitride (BeN), or calcium nitride (Ca,N); (PPS). iii) sodium metaborate (NaBO), sodium tetraborate 3. The composition of claim 1 wherein the at least one (NaBO7), NaBas, NaB. NaBs, calcium aluminum thermoplastic polymer is present in about 30 wt.% to about triborate (CaAlBO,; johachidolite), magnesium diboride 70 wt.% of the composition. (MgB), MgBOs (suanite): CaAlBO, (johachidolite); 4. The composition of claim 1 wherein the inorganic filler LiBOo: LiBO, CaBO, sodium metaborate (NaBO), 10 sodium tetraborate (NaBO,), NaBO(OH)4.8HO, or is one or more of carbon black, white carbon, silica, Zirco disodium octaborate tetrahydrate; nium silicate, alumina, hydrated alumina, aluminum trihy iv) Mg-Si, CaSi, KSi, Rba.Si. Cs.Si. CaSi, Na-Si, CaSi, drate, hydrated magnesium, barium sulfate, barium titanate, Sodium silicide (Na2Si), or magnesium silicide (MgSi); titanium oxide, magnesium oxide, molybdenum oxide, tin V) silica, silicon dioxide (SiO2), thaumasite (CaSi(CO) 15 oxide, Zinc oxide, talc, mica, glass beads, hollow glass balls, (SO4)(OH)12(H2O)), olivine; or epidote; or clay, silicone oil, quartz, barium carbonate, calcium carbon Vi) an amino acid, Vitamin A, vitamin E, ascorbic acid, or ate, or magnesium carbonate. lipoic acid. 5. The composition of claim 1 wherein the inorganic filler While specific embodiments have been described above is present in about 1 wt.% to about 30 wt.% of the compo with reference to the disclosed embodiments and examples, sition. these embodiments and examples are only illustrative and do 6. The composition of claim 1 wherein the alkali metal not limit the scope of the invention. Changes and modifica nitrite or alkaline earth metal nitrite comprises lithium nitrite, tions can be made in accordance with ordinary skill in the art Sodium nitrite, potassium nitrite, magnesium nitrite, or cal without departing from the invention in its broader aspects as cium nitrite. defined in the following claims. 25 7. The composition of claim 1 further comprising an anti All publications, patents, and patent documents are incor oxidant, wherein the antioxidant comprises an amino acid, porated by reference herein, as though individually incorpo Vitamin A, Vitamin E. ascorbic acid, or lipoic acid. rated by reference. The invention has been described with 8. The composition of claim 1 wherein composition has a reference to various specific and preferred embodiments and melt index of 0.1 g/10 minto 10.0 g/10 min. techniques. However, it should be understood that many 30 9. The composition of claim 1 wherein the flame retardant Variations and modifications may be made while remaining additive is present in about 100 parts to 250 parts by weight of within the spirit and scope of the invention. the composition, and theat least one thermoplastic polymeris What is claimed is: 100 parts by weight. 1. A halogen free resin composition comprising: 10. A computing system, input device, or computer com at least one thermoplastic polymer; 35 ponent comprising the composition of claim 1. an inorganic filler; and 11. A computing system, comprising: a flame retardant additive, wherein the flame retardant at least one component selected from the group consisting additive comprises an alkali metal nitrite; an alkaline essentially of a housing, an input device, and a cable, earth metal nitrite; or a combination thereof, where in wherein the component comprises a halogen free resin, the flame retardant additive is present in about 25 parts to 40 that includes, 250 parts by weight of the composition, and the at least at least one thermoplastic polymer; one thermoplastic polymer is 100 parts by weight. an inorganic filler; and 2. The composition of claim 1 wherein the thermoplastic a flame retardant additive, wherein the flame retardant polymer comprises one or more of polyethylene (PE): ethyl additive comprises an alkali metal nitrite; an alkaline ene-vinyl acetate copolymer (EVA); ethylene-ethyl acrylate 45 earth metal nitrite; or a combination thereof, wherein the copolymer (EEA); ethylene-methyl methacrylate copolymer flame retardant additive is present is about 25 parts of (EMMA); polypropylene (PP); polystyrene (PS); polyacry 250 parts of weight of the composition, and the at least lonitrile; acrylonitrile-butadiene-styrene copolymer (ABS); one thermoplastic polymer is 100 parts by weight. nylon-6: nylon-6,6; polycarbonate (PC); polyurethane; biaxi ck ck ck ck ck