STABILIZATION OF POLYMERS AFTER EXPOSURE TO OXIDATION

Abstract: Disclosed is polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyethylene, polypropylene, polyamide, polyimide, polyether, polyester, or polyvinyl acetate containing about 0.005 to about 10 phr of a stabilizer having general formula (I), (II) or (III): where A is C, P, Sn, Si, or B, X is =C=C=, -C C-, (a), (b), (c), (d) each Y is idependently selected from O, S, and N, each R is idependently selected from hydrogen, alkyl from C>1< to C>24<, aryl from C>6< to C>24<, alkaryl from C>7< to C>24< and aralkyl from C>7< to C>24<, each R>1< is independently selected from R, OR, RCO, ROCO, ROCO>2<, P(R)>2<, P(OR)>2<, PR(OR), N(R)>2<, (R)>2<NCO, (R)>2< NCO>2<, SR, and halogen, where two R>1< groups can be bridged together to form a ring, each R>2< is independently selected from R, RCO, ROCO, P(OR)>2<, Sn(R)>q<(OR)>3-q<, SnR>q<(OCOR)>3-q<, Si(R)>q<(OR)>3-q<, and BR>q<(OR)>2-q<, where two R>2< groups can be bridged together to form a ring, each R>3< is independently selected from R, RCO, ROCO, ROCO>2<, OR, SR, N(R)>2<, OP(R)>2<, and OP(OR)>2<, m is 0 when A is P or B and is 1 when A is Sn, Si, or C, n is 0 when Y is O or S and is 1 when Y is N, p is 0 to 4, depending on the number of available sites, and q is 0 to 3 for the tin stabilizers and 0 to 2 for the boron stabilizers. Also disclosed is a method of preventing these polymers from discoloring after exposure to oxidation.

Description: "STABILIZATION OF POLYMERS AFTER EXPOSURE TO OXIDATION" THIS INVENTION relates to the use of stabilizers to reduce the discoloration of certain polymers after they have been exposed to oxidation. A number of different polymers, including polyvinyl chloride (PNC), polycarbonates, polyurethane, polyethylene, and polypropylene, are used to make various medical devices and as packaging for food. Sterilization can be accomplished by exposing the devices or packages to gamma radiation. However, the gamma radiation can degrade or yellow the polymer, making it unsuitable or less acceptable for certain applications. Polymers such as polyethylene, polypropylene, and PVC can also degrade and yellow after heating. According to one aspect of this invention there is provided a polymer which comprises polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyurethane, polyethylene, polypropylene, polyamide, polyimide, polyether, polyester, or polyvinyl acetate containing about 0.005 to about 10 plir of a stabilizer having the general formula: where A is C, P, Sn, Si, or B, X is =C=C=, -C ≡ C- each Y is independently selected from O, S, and N, each R is independently selected from hydrogen, alkyl from C, to C 24 , aryl from C 6 to C 24 , alkaryl from C 7 to C 24 , and aralkyl from C 7 to C 2 ,,.each R, is independently selected from R, OR, RCO, ROCO, ROCO 2 , P(R) 2 , P(OR) 2 , PR(OR), N(R) 2 , (R) 2 NCO, (R) 2 NCO 2 , SR , and halogen , where two R, groups can be bridged together to form a ring, each R 2 is independently selected from R, RCO, ROCO, P(OR) 2l Sn(R) q (OR)^, SnR^OCOR)^, Si(R) q (OR)^, and BR q (OR) 2-q , where two R 2 groups can be bridged together to form a ring, each R 3 is independently selected from R, RCO, ROCO, ROCO 2 , OR, SR, N(R) 2 , OP(R) 2 , and OP(OR) 2 , m is 0 when A is P or B and is 1 when A is Sn, Si, or C, n is 0 when Y is O or S and is 1 when Y is N, p is 0 to 4, depending on the number of available sites, and q is 0 to 3 for the tin stabilizers and 0 tp 2 for the boron stabilizers. When a particular type of stabilizer is added to certain polymers the polymers degrade and yellow substantially less after exposure to oxidation. Some of the stabilizers of this invention are novel compounds while others are commercially available. Some of these stabilizers are polymeric and resist leaching or migration from the polymer, thereby further extending the life of the polymer. The stabilizers of this invention have the general fomula: where A fs C, P, Sn, Si, or B, X is =C=C= -C≡C-, each Y is independently selected from O, S, and N, each R is independently selected from hydrogen, alkyl from C, to C 24 , aryl from C 6 to C 24 , alkaryl from C 7 to C 24 , and aralkyl from C 7 to C 24 , each R, is independently selected from R, OR, RCO, ROCO, ROCO 2 , P(R) 2 , P(OR) 2 , PR(OR), N(R) 2 , (R) 2 NCO, (R) 2 NCO 2 , SR, and halogen, where two R t groups can be bridged together to form a ring, each R 2 is independently selected from R, RCO, ROCO, P(OR) 2 , Sn(R) q (OR)^, SnR^OCOR)^, Si(R) q (OR)^, and where two R 2 groups can be bridged together to form a ring, each R 3 is independently selected from R, RCO, ROCO, ROCO 2 , OR, SR, N(R) 2 , OP(R) 2 , and OP(OR) 2 , m is 0 when A is P or B and is 1 when A is Sn, Si, or C, n is 0 when Y is O or S and is 1 when Y is N, p is 0 to 4, depending on the number of available sites, and q is 0 to 3 for the tin stabilizers and 0 to 2 for the boron stabilizers. Groups that can bridge two R, or two R 2 groups together to form a ring include R 4, -HC=CH- -CH 2 O- -CH 2 NH- -HC=N-, and -CH 2 S, where R 4 is alkylene from C, to C 24l arylene from C 6 to C 24 , (aryl)alkylene from C 7 to C 24 , (alkyl)arylene from C 7 to C 24l alkanediyl from C, to C 24l (aryl)alkanediyl from C 7 to C 24 , -CO-(alkyiene)-CO- fram C, to C 24l -CO-arylene-CO- from C 6 to C 24 , -CO-(aryl)alkylene-CO- from C 7 to C 24 ,-CO-(alkyl)arylene-CO)-fromC 7 toC 24 , Si(R) 2 , SiR(OR), Si(OR) 2 , P(OR), B(OR), Sn(R) 2l SnR(OR), or SnR(O-CO-R). Preferably, A is C, X is -HC=HC-, Y is O, R is benzyl, R, is H, R 2 is R, R 3 is R_ R 4 is alkylene from C, to C 8 , (aryl)alkylene from C 7 to C 8 , or -CO- (aryl)alkylene-CO- from C 7 to C 8 , and q is O because those compounds work well and are readily available. Stabilizers where each R, is hydrogen are especially preferred as they are more effective. When X is =C=C= the stabilizers can be either cis or trans, but the cis stabilizers are preferred because they are less expensive. The following are examples of some of the stabilizers included within the scope of the above formulas (if Y is N, there is an additional R 3 group on Y): R, Examples of stabilizers having a cyclic structure include: Examples of stabilizers having the above structure include 4,7-dihydro-l,3- dioxepins, ethers and esters of butene-l,4-diol, and phthalans. These stabilizers can be prepared by condensing an allylic diol, or an aromatic analog of an allylic diol, with an aldehyde, ketone, acid, acid halide, ester, alkyl halide, or alcohol or by other reactions known to those skilled in the art, to form derivatives. Preferred stabilizers include cis-2-butene-l,4-diol, cis-4- benzyloxy-2-buten-l-ol, and cis-l,4-dibenzyloxy-2-butene. The stabilizer may be a phthalan. A B c In the above. formulas, r can be 1 to 1000, but is preferably 1 to 5. Examples of polymers having formula A include poly(2-butenylene adipate), poly(2-butenylene- terephthalate, and poly[oxy(2-butenylene)j. in formulas B and C , the preferred backbones are polyesters, polyethers, and polyketones, and the preferred pendant groups are 4,7-dihydro-l ,3-dioxeρin, phthalan, and 2-butene- 1 ,4-diol. Examples of such compounds include the condensate of poly(ethylene-co-carboπ monoxide) with 2-butene-1 ,4-diol. The polymeric stabilizers are expected to be more effective as they have less tendency to migrate or leach out of the stabilized polymer . Preparation of these polymers can be achieved by reactions known to those skilled in the art. For example, the polymeric esters can be prepared by reacting the diol (see the first formulas where Y is oxygen and R\ is hydrogen) with a diester, diacid, diacid chloride, or dianhydride. The stabilizers of this invention are effective against oxidation of PVC, polycarbonates, polyurethane, polypropylene, polyethylene, polyvinylidene chloride, polyamides, polyimides, polyethers, polyesters, polysiloxanes, polyurethanes, polysulfones, and polysulfides. The preferred polymers are PVC, polycarbonates, polypropylene, and polyethylene because those polymers are more frequently used in medical applications where they are subjected to gamma radiation; particularly preferred is PVC. Thus the invention also relates to a polymer that has been subjected to oxidizing heat or radiation. The polymer can be stabilized by the addition of about 0.005 to about 10 phr (parts by weight per 100 parts by weight of the polymer) of the stabilizer to the polymer. Less stabilizer is less effective and more stabilizer offers little additional benefit. The preferred amount of stabilizer is about 0.2 to about 6 phr. The stabilizer can be added to a polymer in a variety of ways, such as mixing the reactants at the beginning or during polymerization. The stabilizer is preferably added after at least 70 wt% of the monomer has polymerized. The stabilizer can be added as a solid or with a solvent as a slurry or a solution. Common organic solvents such as N-methylpyrrolidone, diglyme, acetamide, acetone, methanol, ethanol, isopropanol, dimethysulfoxide, and dimethylformamide can be used; water can also be used. Water miscible solvents, such as acetone, tetrahydrofuran, and methanol, are preferred for PVC. It is preferable to add the stabilizer in a solvent as that achieves a more uniform distribution of the stabilizer in the polymer. The stabilizer can also be added during the drying or compounding of the polymer. Various methods can be used for compounding, including milling, dry mixing, and extrusion. The stabilizers function as antioxidants to inhibit various forms of oxidation. The invention also provides polyvinyl chloride, polyurethane, polyethylene, polypropylene, or polycarbonate containing about 0.2 to about 6 phr of a stabilizer having the general formula: where R 2 is R, R 3 is R, R 4 is alkylene from C, to C 8 , (aryl)alkylene from C 7 to C β , or -CO-(aryl)alkylene-CO- from C 7 to C 8 , R is benzyl, and r is 1 to 5. This polymer may have been subjected to gamma radiation. The invention additionally provides a method of preventing a polymer which comprises polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyethylene, polypropylene, polyamide, polyimide, polyether, polyester, or polyvinyl acetate from discoloring after exposure to oxiddation comprising mixing into said polymer about 0.005 to about 10 phr of a stabilizer having the general formula: where A is C, P, Sn, Si, or B, X is =C=C=, -C≡C-, each Y is independently selected from O, S, and N, each R is independently selected from hydrogen, alkyl from C, to C 24 , aryl from C 6 to C 24 , alkaryl from C 7 to C 24l and aralkyl from C 7 to C 24 , each R, is independently selected from R, OR, RCO, ROCO, ROCO 2 , P(R) 2l P(OR) 2 , PR(OR), N(R) 2 , (R) 2 NCO, (R) 2 NCO 2 , SR, and halogen, where two R, groups can be bridged together to form a ring, each R 2 is independently selected from R, RCO, ROCO, P(OR) 2 , Sn(R) q (OR)^, SnR^OCOR)^. Si(R) q (OR)^, and BR^OR)^, where two R 2 groups can be bridged together to form a ring, each R 3 is independently selected from R, RCO, ROCO, ROCO 2 , OR, SR, N(R) 2 , OP(R) 2 , and OP(OR) 2 , m is 0 when A is P or B and is 1 when A is Sn, Si, or C, n is 0 when Y is O or,S and is 1 when Y is N, p is 0 to 4, depending on the number of available sites, and q is 0 to 3 for the tin stabilizers and 0 to 2 for the boron stabilizers. The following examples further illustrate this inventioi EXAMPLES 1 to 13 To a mixture of 150.00 g PVC (sold by Occidental Chemical Corporation as "Oxy 240"), 0.30 g stearic acid (used as a lubricant), 0.23 g of a zinc and calcium mixed salts of mixed fatty acids (used as a heat stabilizer, sold by Witco as "Mark 152 S"), 97.50g dioctyl phthalate (used as a heat stabilizer and to increase flexibility). 15.00 g epoxidized soy bean oil (used as an HC1 scavenger to reduce degradation; sold by Witco as "Drapex 6.8"), was added a stabilizer. The mixture was thoroughly blended and hot milled at 149°C (300°F) for 5 minutes. The resulting PVC sheet was cut and pressed into a 4"x3"xl/4" (10x8x0.6 cm) plaque at 165.5°C (330°F). The plaque was divided into two smaller pieces. One was saved for comparison and one was subjected to γ radiation at a dose of 50 kGy. The irradiated piece was again divided into two pieces and one of these pieces was oven aged at 50°C for 48 hours. All of the samples were measured for yellowness index with a Macbeth 2020 Plus Color Eye Spectrometer, as described by the Hunter equations (see "The Measurement of Appearance" by Richard S. Hunter, John Wiley & Sons, New York, 1975). The following table gives the stabilizers used and the results. As can be observed from the above table, after γ rad.at.on the po.ymers that contained a stabilizer had s i gn.f.cant.y less discoloration than the contro. samples

Claims: CLAIMS 1. A polymer which comprises polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyurethane, polyethylene, polypropylene, polyamide, polyimide , polyether, polyester, or polyvinyl acetate containing about 0.005 to about 10 phr of a stabilizer having the general formula: where A is C, P, Sn, Si,- or B, X is =C=C=. -C≡C-, each Y is independently selected from O, S, and N, each R is independently selected from hydrogen, alkyl from C, to C 24 , aryl from C 6 to C 24 , alkaryl from C 7 to C 24 , and aralkyl from C 7 to C 24 , each R, is independently selected from R, OR, RCO, ROCO, ROCO 2 , P(R) 2l P(OR) 2 , PR(OR), N(R) 2 , (R) 2 NCO, (R) 2 NCO 2 , SR, and halogen, where two R, groups can be bridged together to form a ring, each R 2 is independently selected from R, RCO, ROCO, P(OR) 2 , Sn(R) q (OR)^, SnR^OCOR)^,, Si(R) q (OR)^, and BR^OR^, where two R 2 groups can be bridged together to form a ring, each R 3 is independently selected from R, RCO, ROCO, ROCO 2 . OR, SR, N(R) 2 , OP(R) 2 , and OP(OR) 2 , m is 0 when A is P or B and is 1 when A is Sn, Si, or C, n is 0 when Y is O or S and is 1 when Y is N, p is 0 to 4, depending on the number of available sites, and q is 0 to 3 for the tin stabilizers and 0 to 2 for the boron stabilizers. 2. A polymer according to Claim 1 wherein said polymer is polyvinyl chloride. 3. A polymer according to Claim 1 wherein said stabilizer has the general formula R, 4 . A polymer according to Claim 1 wherein said stabilizer has the general formula: R3 5. A polymer according to Claim 1 wherein said stabilizer is cis-2-butene-l ,4- diol. 6. A polymer according to Claim 1 wherein said stabilizer is cis-4-benzyioxy-2-buten-1 -of. 7. A polymer according to Claim 1 wherein said stabilizer is cis-1 ,4-dibenzyloxy-2-butene. 8. A polymer according to Claim 1 wherein said stabilizer is a 4,7-dihydro-1 ,3- dioxepin. 9. A polymer according to Claim 1 wherein said stabilizer is a phthalan 10. A polymer according to Claim 1 wherein said stabilizer has the structure where R is alkylene from C, to C 24 , arylene from C 6 to C 24l (aryl)alkylene from C τ to C 2 _,, (alkyl)arylene from C 7 to C 2 <, alkanediyl from C, to C 2 , (aryl)alkanediyl from C 7 to C 24 , -CO-(alkylene)-CO- from C, to C 24 , -CO-arylene-CO- from C 6 to C 24 , -CO- (aryl)alkylene-CO- from C 7 to C 2 <. -CO-(aikyl)arylene-CO)- from C 7 to C 2 „, Si(R) 2l SiR(OR). Si(OR) 2 , P(OR). B(OR). Sn(R) 2 , SnR(OR), or SnR(O-CO-R), and r is 1 to 1000. 11. A polymer according to Claim 10 wherein said stabilizer has pendant 4,7-dihydro-l,3-dioxepin groups. 12. A polymer according to Claim 10 wherein said stabilizer has pendant phthalan groups. 13. A polymer according to Claim 10 wherein said stabilizer has pendant 2- butene-1, 4-diol groups. 14. A polymer according to Claim 10 wherein said stabilizer is a polyether having pendant 2-butene-l, 4-diol groups. 15. A polymer according to Claim 10 wherein said stabilizer is a polyester having pendant 2-butene-l, 4-diol groups. 16. A polymer according to Claim 1 wherein A is C, X is -HC=CH-, Y is O, R is benzyl, R, is H, R 2 is R, R 3 is R, R„ is alkylene from C, to C β , (aryl)alkylene from C 6 to C β , or -CO-(aryl)alkylene-CO- from C 6 to C fl , or q is 0. 17. A polymer according to any one of the preceding Claims that has been subj ected to oxidizing heat or radiation . 18. Polyvinyl chloride, polyurethane, polyethylene, polypropylene, or polycarbonate containing about 0.2 to about 6 phr of a stabilizer having the general formula: where R 2 is R, R 3 is R, R 4 is alkylene from C, to C 8l (aryl)alkylene from C 7 to C 8 , or -CO-(aryl)alkylene-CO- from C 7 to C β , R is benzyl, and r is 1 to 5. 19. Polyvinyl chloride according to Claim 18 that has been subjected to gamma radiation. 20. A method of preventing a polymer which comprises polyvinyl chloride , polyvinylidene chloride, polycarbonate, polyethylene, polypropylene, polyamide, polyimide, polyether, polyester, or polyvinyl acetate from discoloring after exposure to oxidation comprising mixing into said polymer about 0.005 to about 10 phr of a stabilizer having the general formula: where A is C, P, Sn, Si, or B, X is =C=C=, -C=C-, each Y is independently selected from O, S, and N, each R is independently selected from hydrogen, alkyl from C, to C 24 , aryl from ' fc 6 to C 24( alkaryl from C 7 to C 24l and aralkyl from C 7 to C 24 , each R, is independently selected from R, OR, RCO, ROCO , ROCO 2 , P(R) 2 , P(OR) 2 , PR(OR), N(R) 2 , (R) 2 NCO, (R) 2 NCO 2 , SR, and halogen, where two R groups can be bridged together to form a ring, each R 2 is independently selected from R, RCO, ROCO, P(OR) 2 , Sn(R) q (OR)^. SnR^OCOR);^, Si(R) q (OR)^, and BR q (OR) 2 _ q , where two R 2 groups can be bridged together to form a ring, each R 3 is independently selected from R, RCO, ROCO, ROCO 2 , OR, SR, N(R) 2 , OP(R) 2 , and OP(OR) 2 , m is 0 when A is P or B and is 1 when A is Sn, Si, or C, n is 0 when Y is O or.-S and is 1 when Y is -N, p is 0 to 4, depending on the number of available sites, and q is 0 to 3 for the tin stabilizers and 0 to 2 for the boron stabilizers. AMENDED CLAIMS [received by the International Bureau on 18 July 2000 (18.07.00); original claims 1, 5-20 replaced by new claims 1, 5-16; remaining claims unchanged (8 pages)] 1. A polymer which comprises polyvinyl chloride, poly inylidene chloride polycarbonate, polyurethane, polyethylene, polypropylene, polyamide, polyimide , polyether, polyester, or polyvinyl acetate containing about 0.005 to about 10 phr of a stabilizer having the general formula: where A is C. P. Sn, Si,- or B, X is -R 1 C=CRι- l -C≡C-, each Y is independently selected from O, S, and N, each R is independently selected from hydrogen, alkyl from C, to C 24 , aryl from C 6 to C 24 , alkaryl from C 7 to C 24 , and aralkyl from C 7 to C 24 , each R, is independently selected from R, OR, RCO, ROCO, ROCO 2 , P(R) 2 , P(OR) 2 , PR(OR), N(R) 2 , (R) 2 NCO, (R) 2 NCO 2 , SR, and halogen, where O 00/56812 25 two R, groups can be bridged together to form a ring, each R 2 is independently selected from R, RCO, ROCO, P(OR) 2l Sn(R) q (OR)^, SnR^OCOR)^, Si(R) q (OR) 3 ) , and BR^OR^. where two R 2 groups can be bridged together to form a ring, each R 3 is independently selected from R, RCO, ROCO, ROCO 2 , OR. SR, N(R) 2 , OP(R) 2 , and OP(OR) 2 , m is 0 when A is P or B and is 1 when A is Sn, Si, or C, n is 0 when Y is O or S and is 1 when Y is N, p is 0 to 4, depending on the number of available sites, and q is 0 to 3 for the tin stabilizers and 0 to 2 for the boron stabilizers, with the provisos that; in general formula (I), when X= -HC=CH-, Y=O and R 2 =H, then at least one of the Ri groups is not H; and, in general formula (II), when X= -R 1 C=CR , Y=0 and A=C, then at least one of the R 3 groups on A is not hydrogen. 2. A polymer according to Claim 1 wherein said polymer is polyvinyl chloride. 3. A polymer according to Claim 1 wherein said stabilizer has the general formula R . 4- A polymer according to Claim 1 wherein said stabilizer ha s the general formula: AMENOED SHEET (ARTICLE 19) O 00/56812 28 - A polymer according to Claim 1 wherein said stabilizer is cis-4-benzyloxy-2-buten-1 -ol. 6- A polymer according to Claim 1 wherein said stabilizer is cis-1 ,4-dibeπzyloxy-2-butene. - A polymer according to Claim 1 wherein said stabilizer is a 4,7-dihydro-1 ,3- dioxepin. 8- A polymer according to Claim 1 wherein said stabilizer is a phthalan 9. A polymer according to Claim 1 wherein said stabilizer has the structure O 00/56812 where R< is alkylene from C, to C 24 , arylene from C G to C 2< , (aryl)alkylene from C 7 to C 2 _ t , (alkyl)arylene from C 7 to C 2< . alkanediyl from C, to C 2/ . (aryl)alkanediyl from C 7 to C 24 , -CO-(alkylene)-CO- from C, to C 24 , -CO-arylene-CO- from C 6 to C 24 , -CO- (aryl)alkyiene-CO- from C 7 to C 2 <. -CO-(alkyl)arylene-CO)- from C 7 to C 2 , Si(R) 2 . SiR(OR), Si(OR) 2 . P(OR), B(OR). Sn(R) 2 , SnR(OR), or SnR(O-CO-R). and r is 1 to 1000. 10. A polymer according to Claim 9 wherein said stabilizer has pendant 4,7- dihydro-l,3-dioxepin groups. 11. A polymer according to Claim 9 wherein said stabilizer has pendant phthalan groups. 12. polymer according to Claim 1 wherein A is C, X is -HC=CH-, Y is O , R is benzyl, R, is H, R 2 is R, R 3 is R, R < is alkylene from C, to C β . (aryl)alkylene from C 6 to C β , or -CO-(aryl)alkylene-CO- from C 6 to C 8 , or q is 0. 13. A polymer according to any one of the preceding Claims that has been subj ected to oxidizing heat or radiation . 14w Polyvinyl chloride, polyurethane, polyethylene, polypropylene, or polycarbonate containing about 0.2 to about 6 phr of a stabilizer having the general formula: where R 2 is R, R 3 is R, R Λ is alkylene from C, to C 6 , (aryl)alkylene from C 7 to C„. or -CO-(aryl)alkylene-CO- from C 7 to C 6 , R is benzyl, and r is 1 to 5. 15. , Polyvinyl chloride according to Claim 14 that has been subjected to gamma radiation. 16. A method of preventing a polymer which comprises polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyethylene, polypropylene, polyamide, polyimide, polyether, polyester, or polyvinyl acetate from discoloring after exposure to oxidation comprising mixing into said polymer about 0.005 to about 1 0 phr of a stabilizer having the general formula: 31 where A is C, P, Sn, Si. or B, X is -R^CR , -C≡C- each Y is independently selected from O, S, and N, each R is independently selected from hydrogen, alkyl from C, to C 2 „, aryl from ' C 6 to C 24 , alkaryl from C 7 to C 24 , and aralkyl from C τ to C 2< , each R, is independently selected from R, OR, RCO, ROCO , ROCO 2 , P(R) 2 . P(OR) 2 , PR(OR). N(R) 2 . (R) 2 NCO, (R) 2 NCO 2 , SR, and halogen, where two R, groups can be bridged together to form a ring, each R 2 is independently selected from R. RCO. ROCO. P(OR) 2 . Sn(R) q (OR)^. SnR q (OCOR)^,, Si(R) q (OR)^,, and BR t _(OR) 2 _ q . where two R 2 groups can be bridged together to form a ring, each R 3 is independently selected from R, RCO, ROCO, ROCO 2 , OR. SR, N(R) 2 , OP(R) 2 , and OP(OR) 2 , m is 0 when A is P or B and is 1 when A is Sn, Si, or C, n is 0 when Y is O or-S and is 1 when Y is -N, p is 0 to 4, depending on the number of available sites, and q is 0 to 3 for the tin stabilizers and 0 to 2 for the boron stabilizers, with the provisos that; in general formula (I), when X= -HC=CH-, Y=O and R =H, then at least one of the Ri groups is not H; and, in general formula (II), when X- -RιC=CR r , Y=O and A=C, then at least one of the R 3 groups on A is not hydrogen.

Inventors: WANG QI, WANG, QI
Applicants: OCCIDENTAL CHEM CO, STEPHENS DINAH, OCCIDENTAL CHEMICAL CORPORATION, STEPHENS, DINAH
Application year: 2000
Main classification: C08K5
IPC codes: C08K5