United States Patent (19) 11) Patent Number: 4,565,833 Buszard Et Al
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United States Patent (19) 11) Patent Number: 4,565,833 Buszard et al. (45) Date of Patent: Jan. 21, 1986 54 FIRE RETARDANT COMPOSITION 4,165,411 8/1979 Marans et al. ...................... 521/107 4,407,981. 10/1983 Aaronson ..... ... 524/130 75) Inventors: David L. Buszard, Woodford; 4,409,341 10/1983 Hira et al. ........................... 521/107 Richard J. Dellar, Altrincham, both of England FOREIGN PATENT DOCUMENTS 1569428 2/1970 Fed. Rep. of Germany . 73) Assignee: Ciba-Geigy AG, Basel, Switzerland 2452357 5/1975 Fed. Rep. of Germany. (21) Appl. No.: 541,352 2610180 9/1977 Fed. Rep. of Germany . 1146173 3/1969 United Kingdom . 22 Filed: Oct. 12, 1983 Primary Examiner-John Kight (30) Foreign Application Priority Data Assistant Examiner-Kriellion Morgan Oct. 12, 1982 GB United Kingdom ................. 8229075 Attorney, Agent, or Firm-Wenderoth, Lind & Ponack 51) Int. Cl........................... C08K 5/52; C08K 5/53; (57) ABSTRACT C08G 18/08 A fire retardant composition for rigid polyurethanes or 52 U.S. Cl. .................................... 521/107; 524/130; polyisocyanurates comprises dimethyl methyl phospho 524/141; 524/143; 528/65; 528/72; 252/609 nate, diethyl ethyl phosphonate or a mixture thereof 58) Field of Search ................ 521/107; 524/130, 141, and a triaryl phosphate, a trialkyl phosphate or an alkyl 524/143; 528/51, 65,72; 252/609 /aryl phosphate in a ratio by weight of 5:95 to 95:5. The composition may also contain a halogen-containing 56 References Cited flame retardant compound. U.S. PATENT DOCUMENTS 3,400,085 9/1968 Kujawa et al. ..................... 521/107 15 Claims, No Drawings 4,565,833 1. 2 have up to about 12 carbon atoms such as methyl, ethyl, FIRE RETARDANT COMPOSITON butyl, octyl, isodecyl and dodecyl. The phosphates used in the compositions of the in The present invention relates to a fire retardant com vention may be those known for use as flame retardants position for use in rigid polyurethanes and 5 in polyurethanes such as trimethyl phosphate, triethyl polyisocyanurates, or blends thereof. phosphate, tributyl phosphate, trioctyl phosphate, tri Polyurethanes are usually made more fire retardant cresyl phosphate, trixylyl phosphate, the alkylated by adding a phosphorus-containing compound a halo phenyl phosphates described in British Patent Specifica gen-containing compound or a mixture thereof to the tion No. 11461.73 and diphenylalkyl phosphates such as reactants used for making the polyurethane. One com 10 diphenyl isodecyl phosphate, and octyl diphenyl phos monly used phosphorus-containing compound is dime phate. thylmethyl phosphonate(DMMP). However, when Preferably the phosphates used are triaryl phos used alone, in polyurethane foams, DMMP gives rise to phates. various processing problems causing voids, splitting and The methods of production of phosphate esters are distortion of the foam. To avoid such problems, or at 15 diverse but all rely on the same type of process. One least to lessen them, the amount of DMMP used is nor process for producing phosphate esters is claimed in mally limited to about 3% of the weight of the foam. British Patent Specification No. 1,146,173. This com Another alternative which has been proposed (U.S. Pat. prises contacting phenol with an alkylating agent con No. 3,509,076) is to replace some of the DMMP and the taining two to sixteen carbon atoms per molecule, and polyol by a reactive phosphorus compound having at 20 contacting the alkylated phenol product with a phos least two active hydrogen atoms per molecule such as phorylating agent to produce a triaryl phosphate ester oxyalkylated dialkyl pyrophosphoric acid. or a mixture of two or more such esters, the proportion DMMP is normally produced by an Arbuzov rear of alkylating agent being within the range of from 5% rangement reaction on trimethyl phosphite in the pres to 65% by weight based on the weight of the phenol ence of a catalyst such as methyl iodide, followed by 25 with which it is contacted. fractional distillation to separate it from unchanged Alkyldiaryl phosphates may be prepared by reacting trimethyl phosphite. In order for DUMP to be free from 2 molar proportions of phenol with 1 molar proportion the disagreeable odour of trimethyl phosphite, the level of phosphorus oxychloride in the presence of an alumin of trimethyl phosphite in the distilled DMMP must be ium chloride catalyst and afterwards reacting with an less than 1 ppm. To achieve this requires careful purifi 30 alcohol. cation. We have surprisingly found that if the phosphates, Another compound which can be used instead of made by processes such as those just outlined, and DMMP is the ethyl analogue, diethyl ethyl phospho which are not 100% pure, are admixed with a phospho nate (DEEP). This is made by a similar process to that nate or mixture of phosphonates containing some tri used for making DMMP and it too has a smell caused by 35 methyl phosphite and/or triethyl phosphite, the tri the presence of triethyl phosphite. methyl phosphite and/or triethyl phosphite is decom If a mixture of methanol and ethanol is used in the posed and its smell disappears. This obviates the need process, the resulting product is a mixture containing for fractional distillation of the phosphonate. DMMP, DEEP together with some diethyl methyl The deodorisation usually occurs within 48 hours, the phosphonate and dimethyl ethyl phosphonate. Such a 40 actual time depending on the amount of trimethyl phos mixture will also contain small amounts of trimethyl phite present, the amount of phosphate used and the phosphite and triethyl phosphite, and may also be used temperature. The time needed can be as little as 12 in the present invention. It will be understood that refer hours. Any temperature up to the boiling point of the ences to a mixture of DMMP and DEEP also includes phosphonate may be used and the ratio of phosphonate mixtures which contain diethyl methyl phosphonate 45 to phosphate may be as given above. and dimethyl ethyl phosphonate. The deodorisation may take place in glass, plastic or We have developed a composition which overcomes metal containers both in the presence or absence of light or minimises the problems associated with the use of or air. The compositions of the present invention are DMMP alone, uses a neutral non-reactive co-compo odourless, colourless liquids which are easily soluble in nent and also enables crude phosphonates containing 50 conventional polyols used in the production of polyure trimethyl phosphite and/or triethyl phosphite in thanes and polyisocyanurates. amounts of up to about 2% to be used. The compositions of the invention may also contain Accordingly the present invention provides a fire other flame retardant compounds, especially halogen retardant composition for rigid polyurethanes or containing compounds, such as aliphatic and aromatic polyisocyanurates which comprises dimethyl methyl 55 bromine-containing compounds or chloroalkyl phos phosphonate diethyl ethyl phosphonate or a mixture phates. Examples of suitable compounds are penta thereof and a triaryl phosphate, a trialkyl phosphate or bromodiphenyl ether, dibromocresyl glycidyl ether an aryl/alkyl phosphate in a ratio by weight of 95:5 to (usually obtained in the form of an isomer mixture), 5:95. tetrabromo bisphenol A, di-bromo neopentylglycol and Preferably the ratio of phosphonate to phosphate is 60 tris(monochloro propy-)phosphate. from 10:90 to 40:60. The amount of other flame retardant additive may Aryl groups in the triaryl phosphates and alkyl/aryl vary over a wide range and may be from 3% up to phosphates may be phenyl or phenyl substituted by one 100% by weight based on the weight of the composition or more alkyl groups having up to about 9 carbon atoms according to the invention. The addition of such addi such as phenyl, cresyl, xylyl, isopropylphenyl, t-butyl 65 tives, especially those containing halogen further im phenyl, and nonylphenyl groups. proves the flame retardancy of the polyurethane or Alkyl groups in the trialkyl phosphates and alkyl/a- polyisocyanurate as shown by the Oxygen Index and ryl phosphates may be straight or branched chain and radiant heat test BS 476 part 7. 4,565,833 3 4. Polyurethanes and polyisocyanurates are made by the Suitable blowing agents are inert, low-boiling liquids reaction of a polyol with a polyisocyanate, in the pres and include halogenated hydrocarbons such as dichlo ence of a blowing agent if a foam is desired. The amount rodifluoromethane, trichlorofluoromethane, methylene of polyisocyanate is varied to produce the desired prod chloride, and hydrocarbons. Alternatively the blowing uct. The present invention is applicable to the whole agent may be derived wholly or partially by chemical range of polymers having an isocyanate index of from 1 reactions which occur during the foaming process such to 2, preferably from 1 to 1.5 e.g. from 1.2 to 1.4. as by the addition of water which reacts with the poly The incorporation of the compositions of the inven isocyanate liberating carbon dioxide. tion into the polyurethanes or polyisocyanurates is ef. The compositions of the invention avoid the prob fected by their addition to the precursors before or 10 lems associated with the use of DMMP alone i.e. the during the formation of the polymers. Preferably, the formation of voids, splitting and distortion e.g. warping. flame retardant composition is mixed with the constitu The phosphate enables DMMP to be used at higher ent containing hydroxyl groups (polyester or polyether levels without these problems occurring. polyol) before its reaction with the polyisocyanate con When certain Mannich base amine polyols are used to stituent. 15 make polyurethane, scorch can sometimes occur. This The flame retardant compositions do not appreciably scorching tendency is reduced when the compositions affect the rate of foam formation and of curing, there fore foaming operations can be performed on standard of the invention are used.