Claims
- 1. A blend of at least two polymers, comprising about, by weight of blend solids,
- (A) 10-60% of at least one acrylic star polymer comprising a crosslinked core which comprise
- (i) a polymer derived from a mixture comprising
- (a) 1-100% by weight of one or more monomers, each having at least two groups, ##STR16## (b) 0-99% by weight of one or more monomers, each having one group ##STR17## (ii) attached to the core, at least 5 arms comprising polymer chains derived from one or more monomers, each having one group, ##STR18## in each of which R is the same or different and is H, CH.sub.3, CH.sub.3 CH.sub.2, CN or CO.sub.2 R' and Z' is O or NR', wherein R' is C.sub.1-4 alkyl,
- wherein
- said arms contain reactive functional groups in an amount of at least about one such group per arm on the average, said star polymer having a primary glass transition temperature above 20.degree. C.;
- (B) 15-60% of at least one matrix-forming polymer selected from polyester, polyether, polyurethanes, and polysiloxanes different than that of polymer (A) and having a primary glass transition temperature below 10.degree. C., a number average molecular weight of at least about 500, and a functionality of at least 2; and
- (C) said blend having crosslinking capability, either in polymers (A) and (B), or in a third, crosslinking polymer.
- 2. The blend of claim 1 wherein the difference in primary glass transition temperature between polymers (A) and (B) is at least 45.degree. C., and polymer (B) has a number average molecular weight less that about 3000.
- 3. The blend of claim 1 wherein the reactive functional groups of (A) comprise hydroxyl groups, with a hydroxyl number within the range of 8 to 120.
- 4. The blend of claim 3 wherein the hydroxyl groups are located randomly through the length of the arms.
- 5. An enamel paint wherein the vehicle comprises a polymer blend of claim 1 suspended or dissolved in suitable solvents, wherein (C) is 10-30% of a nitrogen-bearing crosslinking resin selected from polyisocyanate and melamine-formaldehyde resin.
- 6. A substrate coated with the enamel of claim 5.
- 7. The enamel of claim 5 wherein (C) is 10-30% of a nitrogen-bearing crosslinking resin.
- 8. The enamel of claim 7 wherein the crosslinking resin is a polyisocyanate.
- 9. The enamel of claim 7 wherein the crosslinking resin is a melamine-formaldehyde resin.
- 10. The enamel of claim 5 wherein the number average molecular weight of polymer (B) is less than about 2000 and the hydroxyl number is at least about 50.
- 11. A film wherein the polymer content comprises the polymer blend of claim 1.
- 12. A molding resin wherein the polymer content comprises the polymer blend of claim 1.
- 13. A consolidated body wherein the polymer content comprises the polymer blend of claim 1.
- 14. The blend of claim 1 wherein acrylic star polymer (A) is made by group transfer polymerization.
- 15. The blend of claim 14 wherein acrylic star polymer (A) is made by an arm/core process comprising
- (A) preparing a "living" polymer by reacting a group transfer initiator with one or more monomers having a carbon-carbon double bond polymerizable by a group transfer polymerization process;
- (B) contacting the resulting "living" polymers with a mixture comprising
- i. 1-100% by weight of a monomer having at least two carbon-carbon double bonds polymerizable by a group transfer polymerizable process and
- ii. 0-99% by weight of a monomer having one carbon-carbon double bond polymerizable by a group transfer polymerization process.
- 16. The blend of claim 1 wherein polymer (B) has a backbone of polyester, polyether or polyurethane, polymer.
CROSS REFERENCE TO RELATED APPLICATION
This is a continuation of application Ser. No. 07/036,098, filed April 8, 1987, which was a continuation-in-part of application Ser. No. 853,424, filed April 18, 1986, now abandoned.
US Referenced Citations (3)
Non-Patent Literature Citations (1)
Entry |
International Publication WO86/00626, Spinelli, Published, Jan. 30,1986. |
Continuations (1)
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Number |
Date |
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Parent |
36098 |
Apr 1987 |
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Continuation in Parts (1)
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Number |
Date |
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853424 |
Apr 1986 |
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