Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-10-10
2003-12-23
Mullis, Jeffrey C. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S064000, C525S065000, C525S066000, C525S069000, C525S071000, C525S191000, C525S206000
Reexamination Certificate
active
06667367
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to compositions containing, propylene polymer materials grafted with polymerized vinyl monomers.
BACKGROUND OF THE INVENTION
Polyolefins are not paintable or coatable because the paints or coatings consist of polar materials like urethanes, acrylics, epoxies, or melamines that have very poor adhesion to nonpolar materials like polyolefins. Typically an adhesion promoter is used as the tie layer between the polyolefin substrate and the paint coating. This extra step adds to the cost of the product, and the coating is not very durable. Grafting the polyolefin with somewhat more polar materials such as vinyl-substituted aromatic compounds, or unsaturated aliphatic acids does not render the surface of molded parts polar enough to make paint adhere to the surface.
Various additives have been proposed for making thermoplastic olefins directly paintable. Thermoplastic olefins are uncrosslinked blends of olefin polymers and polyolefin elastomers. For example, U.S. Pat. No. 5,959,030 discloses a directly paintable thermoplastic olefin (TPO) composition containing, in addition to the TPO, (1) a low molecular weight maleic anhydride-grafted propylene homopolymer or ethylene/propylene random copolymer, (2) a maleic anhydride-grafted olefin polymer material, and (3) a functionalized polymer that is reactive with the anhydride groups of the grafted polymers. U.S. Pat. No. 5,962,573 discloses a directly paintable TPO composition containing, in addition to the TPO, (1) an oxidized polyethylene wax, (2) a propylene homopolymer or copolymer grafted with an anhydride of an aliphatic &agr;,&bgr;-unsaturated dicarboxylic acid, (3) a functionalized polymer that is reactive with the anhydride groups of the grafted polymers, optionally (4) a polyolefin rubber grafted with an anhydride of an aliphatic &agr;,&bgr;-unsaturated dicarboxylic acid, and optionally (5) a low molecular weight ethylene polymer grafted with an anhydride of an aliphatic &agr;,&bgr;-unsaturated dicarboxylic acid.
However, there is still a need for polypropylene graft copolymer compositions that can meet-the more stringent requirements for paint adhesion and durability that are required in today's marketplace, particularly in the automotive industry.
SUMMARY OF THE INVENTION
The composition of this invention comprises, by weight,
(1) 100 parts of a graft copolymer composition comprising (a) a graft copolymer comprising a backbone of a propylene polymer material having graft polymerized thereto at least one vinyl monomer capable of being polymerized by free radicals, (b) at least 5% of a rubber component, based on the total weight of the graft copolymer composition, and, optionally, (c) about 5% to about 40% of abroad molecular weight distribution propylene polymer material, based on the total weight of the graft copolymer composition;
(2) about 5 to about 20 parts per hundred parts of the graft copolymer composition. of an oxidized polyethylene wax having a melting point of less than 116° C. and an acid number-of less than 40;
(3) about 5 parts to about 20 parts per hundred parts oft he graft copolymer composition of a propylene homopolymer or a propylene copolymer with ethylene or a 4-8 C alpha-olefin having an ethylene or alpha-olefin content of about 0.5% to about 20%, grafted with an anhydride of an aliphatic &agr;,&bgr;-unsaturated dicarboxylic acid and having an anhydride content of about 2 to about 5%;
(4) a functionalized polymer that is reactive with the anhydride groups of the grafted polymers, selected from the group consisting of:
(a) about 2 to about 6 parts per hundred parts of the graft copolymer composition of an amine-terminated polyalkylene glycol;
(b) about 2 to about 6 parts per hundred parts of the graft copolymer composition of a hydroxy-terminated polyolefin;
(c) about 2 to about 6 parts per hundred parts of the graft copolymer composition of a hydroxy-terminated polybutadiene;
(d) about 2 to about 8 parts per hundred parts of the graft copolymer composition of a hydroxy-terminated olefin/alkylene oxide copolymer;
(e) about 2 to about 8 parts per hundred parts of the graft copolymer composition of a hydroxy-terminated polyalkylene oxide;
(f) about 2 to about 8 parts per hundred parts of the graft copolymer composition of a methoxy-terminated polyalkylene oxide;
(g) about 2 to about 8 parts per hundred parts of the graft copolymer composition of an amine-terminated olefin/alkylene oxide copolymer, and
(h) mixtures thereof;
(5) optionally, about 4 to about 30 parts per hundred parts of the graft copolymer composition of a polyolefin rubber grafted with an anhydride of an aliphatic &agr;,&bgr;-unsaturated dicarboxylic acid, having an anhydride content of at least 0.3% but less than 3% and comprising a polymer of ethylene and a 3-8 C alpha-olefin, optionally containing about 0.5% to about 10% of a diene, having an ethylene content of about 30% to about 70%, with the exception that when the amount of (2)+(3) is equal to or greater than 25 parts per hundred parts of the graft copolymer composition, (5) must be present, and
(6) optionally, about 5 to about 20 parts per hundred parts of the graft copolymer composition of an ethylene polymer grafted with an anhydride of an aliphatic &agr;,&bgr;-unsaturated dicarboxylic acid, having an anhydride content of about 1% to. about 16% and a number average molecular weight M
n
of about 500 to about 5000.
Injection molded parts such as automobile bumpers made from this composition are directly paintable with polar paints or coatings without the need for a layer of adhesion promoter between the graft copolymer composition and the paint, and exhibit excellent paint adhesion and durability.
DETAILED DESCRIPTION OF THE INVENTION
Component (1) of the composition of this invention is a graft copolymer composition comprising (a) a graft copolymer comprising a backbone of a propylene polymer material having graft polymerized thereto at least one vinyl monomer capable of being polymerized by free radicals, (b) a rubber component, and, optionally, (c) a broad molecular weight distribution propylene polymer material.
The propylene polymer material that is used as the backbone of the graft copolymer can be:
(1) a crystalline homopolymer of propylene having an isotactic index greater than 80, preferably about 85 to about 99;
(2) a crystalline copolymer of propylene and an olefin selected from the group consisting of ethylene and 4-10 C alpha-olefins, provided that when the olefin is ethylene, the maximum polymerized ethylene content is about 10%, preferably about 4%, and when the olefin is a 4-10 C alpha-olefin, the maximum polymerized content thereof is about 20% by weight, preferably about 16%, the copolymer having an isotactic index greater than 85;
(3) a crystalline terpolymer of propylene and two olefins selected from the group consisting of ethylene and 4-8 C alpha-olefins, provided that the maximum polymerized 4-8 C alpha-olefin content is 20% by weight, preferably about 16%, and, when ethylene is one of the olefins, the maximum polymerized ethylene content is 5% by weight, preferably about 4%, the terpolymer having an isotactic index greater than 85;
(4) an olefin polymer composition comprising:
(a) about 10% to about 60% by weight, preferably about 15% to about 55%, of a crystalline propylene homopolymer having an isotactic index greater than 80, preferably about 85 to about 98, or a crystalline copolymer of monomers selected from the group consisting of (i) propylene and ethylene, (ii) propylene, ethylene and a 4-8 C alpha-olefin, and (iii) propylene and a 4-8 C alpha-olefin, the copolymer having a polymerized propylene content of more than 85% by weight, preferably about 90% to about 99%, and an isotactic index greater than 85;
(b) about 5% to about 25% by weight, preferably about 5% to about 20%, of a copolymer of ethylene and propylene or a, 4-8 C alpha-olefin that is insoluble in xylene at ambient temperature; and
(c) about 30% to about 70-by weight, preferably about 40% to about 65%, of an elastomeric copolymer of mo
Basell Poliolefine Italia S.p.A.
Mullis Jeffrey C.
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