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Home , Polyvinyl chloride

United States Patent [191 [11] 4,329,272 Dufour [45] May 11, 1982

[54] FLAME-RETARDANT 4,234,701 11/ 1980 Abolins et a1...... 525/74 [75] Inventor: Danlel_ L. Dufour, Longmeadow, 4,269,950 5/1981 Abolins et a1...... 525/74 Mass FOREIGN PATENT DOCUMENTS [73] Assignee: Monsanto Company, St. Louis, Mo. 900079 5/1972 Canada - 1624 5/1979 European Pat, Off...... 525/74 [21] Appl. No.: 244,577 1354000 5/ 1974 United Kingdom . [22] Filed: Mar- 17, 1981 OTHER PUBLICATIONS [51] Int. (:1.3 ...... C08K 5/02; COSL 37/00; Derwent AbsL, 7945 was 2-1743, Torayind, “Impact C08L 51/00; C08K 5/49 Resistant ”. [52] [1.3. C1...... 524/288; 525/74; Chem_ Abst.’ VOL 92 (111614)‘) 1980, “ 525/207; 524/343; 524/371; 524/373; 524/467; Action of Decabromodiphenyl Oxide on ”. [58] Feld fs arch 524/550245;/52%";/“7i9 Chem. Abst., v01. 90-39649b, 1979, Larkin et a1. “Flame 1 o e260/338 ...... UA’ 45.7 R? 45.95 ., R, 45.85, P; ?sltlzlrdmg- Halogen _ Contammg- » Compost-_ [56] References Cited Primary Examiner—Herbert J. Lilling U.S. PATENT DOCUMENTS Attorney, Agent, or Firm—~David Bennett; William J. 3,626,033 12/1971 Keskkula et a1...... 525/207 Farrington; Paul D. Matukaitis 3,632,839 1/1972 Young et a1...... 525/207 3,641,212 2/1972 Narayana et a1. 525/207 [57] ABSTRACI‘ 3,717,688 2/1973 Kayanagi et a1...... 525/78 Styrene/maleic anhydride polymers can be made more 3,720,734 3/1973 Kopacki et a1...... 525/207 resistant to combustion by incorporation therein of 3,759,863 9/1973 Czekay et a1. 260/336 AQ minor amounts of polyvinyl . The compositions 3,882,192 5/1975 Elghani et a1...... , 525/67 3,887,639 6/1975 Kopacki et a1. .. 525/83 can also comprise MBS, ABS and other ?ame retardant 3,919,354 11/1975 Moore et a1...... 525/261 additives. 4,048,263 9/ 1977 Lee ...... 525/207 4,205,140 5/1980 Llebig et a1...... 525/74 4 Claims, No Drawings 4,329,272 1 2 in whole or in part by other vinylaromatic FLAME-RETARDANT POLYMERS. such as a-methyl styrene, bromostyrene, chlorostyrene, p-methylstyrene and vinyl toluene. Likewise the anhy BACKGROUND OF THE INVENTION _ dride component can be supplied in whole or in part by ‘This invention relates to ?ame retardant polymers itaconic, citraconic or aconitic anhydride. The copoly and particularly to ?re retardant terpolymers of styrene merizable is conventionally selected from C1 and maleic anhydride. to C3 acrylates and methacrylates and unsaturated ni Polymers of styrene and maleic anhydride are triles. Typically comonomers are , known for their high heat distortion temperature but ethyl acrylate and acrylonitrile. In a preferred terpoly they have the limitation that they burn when ignited. 0 mer the anhydride provides from 20 to 30% and methyl For many end uses a polymeric composition is methacrylate provides from 5 to 15% 0f the Component required to be ?ame-retardant to meet the applicable A polymer weight. safety codes. The polymer has a uniform composition and in prac The present invention provides a route towards ?ame tice this implies controlled late addition of the anhy retardant compositions based on styrene/maleic anhy dride in the manner taught for example in U.S. Pat. No. dride polymers that also retain good strength and mold 2,971,939 and 3,336,267. ing characteristics. Component B of the polyblend is While it is known that polyvinyl chloride is resistant and it is understood that this term also is intended to to burning, its use as a ?ame retardant additive may be embrace various degrees of halogenation of a basic impeded if this requires signi?cant sacri?ce of other hydrocarbon chain. Thus the term includes halogenated desirable properties such as impact strength. polyvinyl chloride and halogenated as DESCRIPTION OF PRIOR ART well as simple polyvinyl chloride which is the most Both styrene/maleic anhydride copolymers and poly common exemplar. of such compounds. The preferred are known in the art and US. Pat. No. Component B is a conventional polyvinyl chloride of 3,626,033 teaches high heat deformation and high im the kind typically sold for molding applications. The pact vinyl chloride molding resins by incorporating proportion of component B actually used depends therein minor amounts of ABS and a styrene/maleic largely on the desired properties of the product. It is anhydride copolymer. ' ' - however found that when Component C is present it is 30 desirable to use from 30 to 40% by weight of Compo DESCRIPTION oF THE INVENTION nent B, not only for good ?ame retardance but also The present invention provides a molding composi because a bene?cial effect on the impact properties is tion comprising: revealed. A. from 20 to 85% by weight of a uniform polymer Component C is conventionally an ABS or an MBS; comprising 50 to 85% by weight of a vinylaromatic that is, a terpolymer of acrylonitrile or methyl methac monomer, from‘ 15 to 30% by weight of an unsatu rylate, butadiene and styrene formed by polymerizing rated dicarboxylic acid anhydride and from O to the other monomers in the presence of a butadiene 20% of a copolymerizable monomer; based rubber.‘ Both these compositions are known to be B. from 15 to 40% by weight of polyvinyl chloride; compatible with both PVC and styrene/maleic anhy and dride copolymers and to function as impact improvers C. from'0 to 40% by weight of a composition com to both. prising a graft copolymer of from 20 to 40% by Component C can however be varied in composition weight of a monomer selected from the group con beyond the above conventional formulations. Thus the sisting of methyl methacrylate and acrylonitrile styrene can be replaced in whole or in part by mono and 80 to 60% by- weight of a vinyl aromatic mono 45 mers such as a-methylstyrene, chlorostyrene, bromos mer, said copolymer being grafted on to from 10 to tyrene, p-methylstyrene or vinyl toluene and the like. 60% of the weight of the composition of a' The rubber need'not be based on butadiene but can be rubber having a temperature below provided by polyisoprene, polychloroprene, polypente , 0° C. . namer, EPDM rubbers and acrylate rubbers. The rub The presence of Component C is a desirable expedi ber can also be a diene-based block or radial block-type ent if the product needs to have good strength proper rubber. ties. However its inclusion renders the effectiveness of the PVC (Component B) lessand in such event to ob The proportion of Component C is determined by the tain very good ?ame retardant characteristics, an added ‘properties of the desired product. However where it is ?ame retardant may be employed. In such compositions used, best results are obtained with a proportion no the preferred ?ame retardants include decabromodi greater than that of Component A. Particular preferred phenylether, halogenated (di)methanodibenzocyclooc polyblends of the invention comprise from 30 to 40% of tene adducts, halogenated paraffin hydrocarbons, halo each of Components A and C. genated octadiene-cyclopentadiene ' adducts, tetra In addition to the three components A, B and C de bromobisphenol A, tetrabromoxylene, pentabromoeth 60 scribed above and the optional ?ame retardant additive ylbenzene, tetrabromobisphenol A diacetate, and bis(’ the compositions of the invention can further comprise tribromophenoxy)ethane. In general the amount of such ?ame retardant adjuvants such as antimony oxide, stabi additive present can be from 1 to 10% by weight of the lizers, , antioxidants, ?llers, mineral fibers, total composition. ‘ pigments and the like in appropriate amounts. Component A of the polyblend is conventionally a 65 The components of the polyblend can be blended in styrene/maleic anhydride copolymer or preferably a any convenient manner but the most suitable technique terpolymer comprising in addition methyl methacry involves the use of a compounder-extruder or a banbury late. However the styrene ‘component can be replaced mixer. 4,329,272 3 4 DESCRIPTION OF THE PREFERRED TABLE l-continued EMBODIMENTS FORMULATIONS & PROPERTIES Comparative Invention The invention is now described with reference to the Mark 1900 0.8 1.6 1.2 1.2 following example which is for the purposes of illustra Plasticizers tion only and is not intended to imply any limitation on Butyl 1.0 1.0 the essential scope of the invention. Stearate The components described below were blended in a K-175 0.3 1.0 Properties number of different ratios and tested for various proper DTUL (°C.) 69 135 112 105 100 125 105 ties. Izod ' ABS l—prepared by the graft emulsion polymeriza (J/M notch) 32 11 150 32 49 39 27 Gardner (.1) 1.7 .l 8.6 2.3 >24 <.l .3 tion of acrylonitrile and styrene in a weight ratio of UL Tests 30:70 in the presence of polybutadiene. ABS-l contains “HB" ratings Pass Fail Pass Marg. Pass Marg 40% by weight of polybutadiene. 15 Fail Fail ABS 2—prepared by the graft suspension polymeri -Dripping No Yes No No No No “V” rating V-O+ Fail V-2 zation of acrylonitrile and styrene in a weight ratio of -Dripping No Yes No 28:72 in the presence of polybutadiene. ABS-2 contains 14% by weight of polybutadiene. 20 From the data on Table 1 it can be seen that, at the S/MA/MM—prepared by polymerizing a monomer levels of reinforcement contemplated, ABS performs mixture of styrene, maleic anhydride and methyl meth somewhat better than MBS. It can also be seen that acrylate to produce uniform polymer composition in certain formulations are substantially superior to others which the above monomers are the weight proportions in their strength properties particularly Gardner im 68:26:6 respectively. 25 pact. It is considered probable that these represent com PVC--Rucon B-221 (Hooker Chemical Co.) positions of signi?cantly greater compatibility than MBS—Acryloid-K 653 (Rohm and Haas Co.) a meth other marginally different systems. An example of this ylmethacrylate butadiene/ styrene terpolymer. effect is provided by a comparison of formulations 1 and Plasticizers/Flow Aids—Butyl Stearate Acryloid 2 where an enormous increase in Gardner impact is K-175—(Rohm and Haas), an acrylic polymer 30 obtained for a relatively minor adjustment in the formu Antioxidants/ Stabilizer lation. Moreover although the blend contains 40% Ethanox 330—an alkylated phenol available from PVC the DTUL is still 31° C. higher than for PVC Ethyl Corp. alone. Mark 1900-—a methyl mercapto-ester complex What is claimed is: available from Argus Chemical Co. EXAMPLE 35 l. A molding composition comprising: A. from 30 to 40% by weight of a uniform polymer The components indicated in Table 1 below were comprising 50 to 85% by weight of a vinylaromatic formulated and tested for their DTUL, (using ASTM D monomer, from 15 to 30% by weight of an unsatu 648.56 on a 12.7 mm><12.7 mm cross-section sample), rated dicarboxylic acid anhydride and from 0 to and Izod impact (using ASTM method D-256.56) Gard 40 20% of a copolymerizable monomer; ner impact was assessed on a 2.54 mm thick sample B. from 30 to 40% by weight of polyvinyl chloride; using a 1.27 cm diameter dart. and The samples were also tested for ?ammability using C. from 30 to 40% by weight of a composition com the UL-94 “V” test and “HB” test. (1) prising a graft copolymer of from 20 to 40% by (1) “Materials designated ‘?re or ?ame-retardant’ 45 weight of a monomer selected from the group con generally are more difficult to ignite or once ignited, sisting of methyl methacrylate and acrylonitrile burn at a slower rate than corresponding conventional and 80 to 60% by weight of a vinyl aromatic mono materials. These terms do not mean that ?re-retardant mer, said copolymer being grafted on to from 10 to materials will not burn. However, when properly used, 60% of the weight of the composition of a substrate Monsanto ?re-retardant additives and materials are rubber having a glass transition temperature below 0° C. useful in helping customers formulate or construct ?n 2. A composition according to claim 1 comprising ished products meeting speci?ed ?re codes and regula from 1 to 10% by weight of a ?ame retardant additive tions.” selected from the group consisting of decabromodi TABLE 1 55 phenylether, halogenated (di)methanodibenzocyclooc tene adducts, halogenated paraf?n hydrocarbons, halo FORMULATIONS & PROPERTIES genated octadienecyclopentadiene adducts, tetra Comparative Invention bromobisphenol A, tetrabromoxylene, pentabromoeth Polymer ylbenzene, tetrabromobisphenol A diacetate, and bis( Components C1 C2 C3 1 2 3 4 60 tribromophenoxy)ethane. £1E)_ 3. A composition according to claim 1 in which Com ABS-1 38 30.4 22.8 ABS-2 12 9.6 7.2 ponent A comprises a copolymerizable monomer se S/MA/MM 100 50 4O 3O 70 50 lected from the group consisting of C1 to C3 acrylates PVC 100 20 40 30 25 and methacrylates and unsaturated nitriles. MBS 25 65 4. A composition according to claim 3 in which Com Stabilizers/ ponent A comprises from 5 to 15% by weight of methyl Antioxidants methacrylate. Ethanox 330 0.3 0.3 0.3 0.3 1|t * i * *