Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L69/00—Compositions of polycarbonates; Compositions of derivatives of polycarbonates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/49—Phosphorus-containing compounds
  • C08K5/51—Phosphorus bound to oxygen
  • C08K5/52—Phosphorus bound to oxygen only
  • C08K5/521—Esters of phosphoric acids, e.g. of H3PO4
  • C08K5/523—Esters of phosphoric acids, e.g. of H3PO4 with hydroxyaryl compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K9/00—Use of pretreated ingredients
  • C08K9/04—Ingredients treated with organic substances
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers
  • C08L71/08—Polyethers derived from hydroxy compounds or from their metallic derivatives
  • C08L71/10—Polyethers derived from hydroxy compounds or from their metallic derivatives from phenols
  • C08L71/12—Polyphenylene oxides
  • C08L71/123—Polyphenylene oxides not modified by chemical after-treatment

Definitions

• This invention relates to polymer blends, and more particularly to blends having flame retardant properties.
• Fire resistance is typically evaluated by the UL-94 test of Underwriters Laboratories (ASTM procedure D3801). In this test, the desirable V-0 rating is given to polymers of which specimens do not burn with flaming combustion for more than 10 seconds after application of a test flame, and specimens do not burn with flaming combustion for a time exceeding 50 seconds upon 10 flame applications to each of 5 specimens; i.e., the "flame-out time" for said samples is not greater than 50 seconds.
• Various types of chemical compounds may be employed as flame retardancy additives. They include halogenated and especially brominated compounds, which often must be used in combination with antimony compounds such as antimony trioxide, and phosphate-based compounds. Such additives are often employed in combination with anti-drip agents such as fluorocarbon polymers.
• organoclays in combination with flame retardancy additives has been disclosed.
• the additives employed are halogen-based.
• US Patent 4,582,866 discloses copolyester elastomers containing as flame retardancy improvers a combination of a bromine compound and antimony trioxide; a clay modified by a quaternary ammonium salt is employed as an anti-drip agent.
• British Patent 1 ,1 14,174 discloses blends of such polymers as polyamides, polystyrenes and olefin polymers with flame retardant additives, which may be halogen- or phosphate-based, and organophilic cation-modified clays as anti-drip agents.
• polyesters may be made flame retardant by the action of a halogenated compound in combination with an antimony or phosphorus compound and an organically modified layered silicate. Similar blends in which the modified clay is used as a "drip suppressant" are disclosed in European patent application 239,986.
• Copending, commonly owned application Serial No. 08/950,092 discloses combinations of a polyester, a halogenated flame retardant, an organoclay, an antimony oxide and a fluorocarbon polymer. This combination of additives is described as enabling a decrease in the amounts of halogenated flame retardant and antimony oxide employed.
• the present invention is based on the discovery that organoclays may be employed as synergists with phosphate-based flame retardant additives in polymer blends, whereby the levels of such additives in said blends may be substantially decreased.
• the function of the organoclay is not simply as an anti-drip agent; it actually forms a synergistic combination with the phosphate-based flame retardant whereby a lower level of the latter may be employed. It has further been found that in certain blends according to the invention, the presence of fluorocarbon polymers is unnecessary and even disadvantageous since such polymers may degrade the flame retardant properties of the blend.
• compositions free from antimony compounds and comprising the following and any reaction products thereof:
• thermoplastic resin (A) a major amount of a first thermoplastic resin
• proportions of components C and D being effective to produce a V-0 rating in the UL-94 test or reduce average flame-out time by at least 10%.
• the invention is directed to said compositions whether or not any chemical interaction has taken place. That is, the invention includes both compositions comprising said components and compositions comprising reaction products thereof. - 4 -
• Components A and B are a first and a second thermoplastic resin. It is intended that said resins differ from each other in structural units.
• component A may be a homopolymer and component B a copolymer comprising structural units identical to those of component A in combination with other structural units. Most often, however, components A and B contain totally different structural units.
• thermoplastic resins are olefin polymers such as polyethylene and polypropylene; polymers of ethylenically unsaturated carboxylic acids and their functional derivatives, including acrylic polymers such as poly(alkyl acrylates), poly(alkyl methacrylates), polyacrylamides, polyacrylonitrile and polyacrylic acid; alkenylaromatic polymers such as polystyrene; diene polymers such as polybutadiene and polyisoprene; polyamides such as nylon-6 and nylon-66; polyesters such as poly(ethylene terephthalate) and poly(butylene terephthalate); polycarbonates such as bisphenol A polycarbonate; and polyarylene ethers such as poly(2,6-dimethyl-1 ,4-phenylene ether) and copoly(2,6- dimethyl-1 ,4-phenylene
• suitable polystyrenes include homopolymers and copolymers.
• the latter embraces high impact polystyrene (HIPS), a genus rubber-modified polystyrenes comprising blends and grafts wherein the rubber is a polybutadiene or a rubbery copolymer of about 70-98% styrene and 2-30% diene monomer.
• HIPS high impact polystyrene
• a genus rubber-modified polystyrenes comprising blends and grafts wherein the rubber is a polybutadiene or a rubbery copolymer of about 70-98% styrene and 2-30% diene monomer.
• component A and B may be compatible, incompatible or chemically or physically compatibilized by known methods. It is often preferred that component B be a commercially conventional adjuvant to component A, such as an impact modifier therefor or a second component of a commercial polymer blend. - 5 -
• the preferred polymer blends are those of polyphenylene ethers, especially with homo- and copolystyrenes including homopolystyrene and styrene copolymers with diene rubbers (e.g., high impact polystyrenes), and those of polycarbonates.
• the polycarbonate blends include those in which component B comprises at least one copolystyrene, especially those in which it comprises one or more styrene copolymers with aliphatic dienes and nitriles (e.g., acrylonitrile -butadiene-styrene or ABS copolymers).
• the copolystyrenes blended with polycarbonates are frequently mixtures of ABS copolymers and styrene-acrylonitrile copolymers.
• Component C may be any one or more phosphate-based organic compound(s) which provide flame retardant properties.
• phosphate-based is meant an organic compound containing at least one phosphate (PO 4 ) group.
• Suitable phosphate-based compounds include triaryl monophosphates such as tricresyl phosphate.
• the preferred phosphate-based compounds are the aryl diphosphates. They include compounds of the formula
• each A 1 is independently a monovalent C ⁇ .2o aromatic radical
• each A 2 is a divalent C 6 -2o aromatic radical
• n is 0-5 and preferably 1.
• Said aromatic radicals may be hydrocarbon or substituted hydrocarbon radicals, with hydrocarbon radicals being preferred.
• aromatic embraces monocyclic and polycyclic fused- and linked-ring radicals, including alkylaromatic radicals such as methylphenyl, dimethylphenyl and 2,2-bis(4-phenylene)propane; i.e., the radical derived from bisphenol A.
• Suitable aryl diphosphates include hydroquinone bis(diphenyl phosphate), resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate) and resorcinol bis(di-2,6-xylyl phosphate).
• the preferred diphosphates are generally 47
• Component C is the sole flame retardant agent in the compositions of the invention. Thus, no halogenated flame retardants are present.
• Component D is at least one organoclay.
• organoclay means a layered clay, usually a silicate clay, derived from a layered mineral and in which organic moieties have been chemically incorporated, ordinarily by ion exchange and especially cation exchange with organic ions and/or onium compounds.
• Illustrative organic ions are mono- and polyammonium cations such as trimethyldodecylammonium and N,N'-didodecylimidazolium.
• Illustrative layered minerals are the kaolinites and the montmorillonites. It is also possible to employ minerals of the illite group, including hydromicas, phengite, brammallite, glaucomite, cejadonite and the like. Often, the preferred layered minerals include those often referred to as 2:1 layered silicate minerals, including muscovite, vermiculite, saponite, hectorite and montmorillonite, the latter often being most preferred. The layered minerals may be synthetically produced, but most often they are naturally occurring and commercially available. A detailed description of suitable layered minerals can be found in US Patent 5,530,052, the disclosure of which is incorporated by reference herein.
• organoclays which are illustrative of those which may be employed include CLAYTONE HY, a montmorillonite cation exchanged with dimethyldi(hydrogenated tallow)ammonium ion available from Southern Clay Products, and montmorillonite cation exchanged with such ions as dodecylammonium, trimethyldodecylammonium, N,N'-didodecylimidazolium, N,N'- ditetradecylbenzimidazolium or methylbis(hydroxyethyl)- (hydrogenated tallow)ammonium.
• CLAYTONE HY a montmorillonite cation exchanged with dimethyldi(hydrogenated tallow)ammonium ion available from Southern Clay Products
• montmorillonite cation exchanged with such ions as dodecylammonium, trimethyldodecylammonium, N,N'-didodecylimidazol
• compositions of this invention may contain conventional additives for polymer blends of these types, with the proviso that no antimony compounds are employed as additives.
• Suitable additives include anti-drip agents, stabilizers, fillers, pigments, dyes, antistatic agents, crystallization aids and mold release agents. Since these are well known in the art, they will not be dealt with in detail herein.
• component A is a polyphenylene ether
• component B is a polymer of one or more ethylenically unsaturated monomers and component C is present at relatively low levels
• fluorocarbon polymers not be employed as anti-drip agents.
• a preferred embodiment of the invention is polyphenylene ether blends wherein the level of component C is less than 20 parts by weight per 100 parts of the combination of components A and B (phr), said blends being free from fluorocarbon polymers.
• the presence of such polymers in these blends may result in degradation of flame retardant properties, as exemplified by UL-94 rating, flame-out time or both.
• compositions of the invention are subject to wide variation.
• Component A is present in major amount with respect to the combination of components A and B, with component B comprising about 3-45% and preferably about 5-40% by weight of said combination.
• Components C and D are present in amounts effective to produce a V-0 rating in the UL-94 test or reduce average flame-out time by at least 10%. This amount will vary with the identities of components A and B.
• component A is a polyphenylene ether
• component B is an addition polymer of one or more ethylenically unsaturated monomers
• the proportion of component C is most often in the range of 10-25 and preferably 15-20 phr. At levels higher than 20 phr, it is frequently unnecessary to employ component D to obtain acceptable flame retardancy; below 15 phr, it may be 47
• component C is typically in the range of about 5-15 and preferably 7- 11 phr. Lower levels may afford little or no flame retardancy even in the presence of component D, and higher levels are unnecessary and may minimize the effect of component D.
• component D it is generally advantageous to employ component D in the amount of 0.08-0.6 phr, with higher levels affording no advantage and even sometimes decreasing flame retardancy and/or degrading any polycarbonate present in the blend. Even within this range some variability of effectiveness is noted, particularly at borderline levels of component C. Those skilled in the art can, however, easily determine effective levels via simple experimentation.
• a fluorocarbon polymer most often polytetrafluoroethylene (PTFE)
• PTFE polytetrafluoroethylene
• compositions of this invention may be prepared by conventional blending techniques for thermoplastic resins. These may include solution blending and melt blending. Melt blending, especially by methods suitable for continuous operation such as extrusion, is often preferred.
• the invention is illustrated by the following examples. All parts and percentages are by weight. Molecular weights are weight average and were determined by gel permeation chromatography. Intrinsic viscosities were determined in chloroform at 25 °C. UL-94 tests were conducted on 1/16" (1.6 mm) specimens.
• the blends were prepared by mixing the constituents in a Henschel mixer and extruding at temperatures in the range of 120-232 °C on a 20-mm twin screw extruder with counterrotating screws. It was found that 21.26 phr of the diphosphate was required to produce a V-0 rating in the UL-94 test.
• organoclay is apparent.
• No substantial effect on flame retardant properties as a result of the presence of PTFE is apparent.
• Example 2 The blending procedure of Example 1 was employed to prepare blends comprising about 81.7% of a linear bisphenol A polycarbonate resin having an intrinsic viscosity of 0.50 dl/g; about 18.3% of a mixture of the following addition copolymers: (1 ) 45.5% of a commercially available emulsion polymerized ABS graft copolymer comprising a discontinuous elastomeric phase (polybutadiene with an average particle size of about 300 nm) and a rigid thermoplastic phase (copolymer of 75 pbw styrene and 25 pbw acrylonitrile) and (2) 54.5% of a styrene-acrylonitrile copolymer (SAN, 75 parts styrene/25 parts acrylonitrile) having a molecular weight of about 90,000; 9.5 phr of resorcinol bis(diphenyl phosphate); and 0.4 phr of PTFE blend.
• Blends similar to those of Example 5 but comprising about 82% polycarbonate, 18% addition polymers and 7.5 phr diphosphate were prepared and tested. The results are given in TABLE VI.
• Blends similar to those of Example 5 but comprising about 82.4% polycarbonate, 17.6% addition polymers and 6.0 phr diphosphate were prepared and tested. The results are given in TABLE VI.

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• 1999
  • 1999-02-17 WO PCT/US1999/003418 patent/WO1999043747A1/en not_active Application Discontinuation
  • 1999-02-17 EP EP99907105A patent/EP1056803A1/de not_active Withdrawn
  • 1999-02-17 JP JP2000533493A patent/JP2002504611A/ja not_active Withdrawn
  • 1999-02-22 TW TW088102570A patent/TW442530B/zh active

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