Endcapped fluoropolymers for coating applications and processes of producing same

A process of producing an endcapped fluorocopolymer, the process comprising:

• forming a fluorocopolymer by copolymerization of:
• (1) from about 40 mol % to about 60 mol % hydrofluoropropene monomers;
• (2) from about 5 mol % to 45 mol % of vinyl ester, vinyl ether or a mixture thereof;
• wherein the vinyl ester has the formula CH2═CR1—O(C═O)XR2 wherein x is 1, R1 is a hydrogen or a methyl group, and R2 is selected from the group consisting of an unsubstituted straight-chain, branched-chain or alicyclic alkyl group having 1 to 12 carbon atoms;
• and wherein the vinyl ether has the formula CH2═CR3—OR4, wherein R3 is a hydrogen or a methyl group, and R4 is selected from the group consisting of an unsubstituted straight-chain, branched-chain or alicyclic alkyl group having 1 to 12 carbon atoms;
• and
• (3) from about 3 mol % to about 30 mol % of hydroxyalkyl vinyl ether having the formula CH2═CR3—O—R5—OH, where R3 is a hydrogen or a methyl group, and R5 is selected from the group consisting of a C2 to C12 unsubstituted straight-chain, branched-chain or alicyclic alkyl group having from 3 to 5 carbons;
• and
• at the end of copolymerization, reacting a radical transfer agent with the fluorocopolymer to produce an endcapped fluorocopolymer;
• wherein the mol % are based on the total of the monomers.

A coating composition comprising:

• (i) one or more endcapped fluorocopolymers formed by the following process:
• forming a fluorocopolymer by copolymerization of
• (1) first monomer(s) consisting essentially of trans-HFO-1234ze in an amount of from about 40 mol % to about 60 mol %,
• (2) second monomer(s) comprising:
• A) vinyl ester monomer represented by formula CH2═CR1—O(C═O)XR2 wherein x is 1 and wherein R1 is either hydrogen or a methyl group and wherein R2 is an unsubstituted branched-chain alkyl group having 6 to 8 carbon atoms including at least one tertiary or at least one quaternary carbon atom, wherein said vinyl ester monomer is present in an amount of from about 5 mol % to about 45 mol;
• and
• B) vinyl ether monomer(s), represented by formula CH2═CR3—O—R4, wherein R3 is either hydrogen or a methyl group and wherein R4 is selected from the group consisting of a substituted or unsubstituted straight-chain or branched-chain alkyl group having 1 to 3 carbon atoms, said vinyl ether monomer(s) preferably being present in amounts of from about 10 mol % to about 40 mol %;
• and
• (3) third monomer(s) consisting of hydroxyalkyl vinyl ether represented by the formula CH2═CR3—O—R5—OH, where R3 is either hydrogen or a methyl group and R5 is selected from the group consisting of a substituted or unsubstituted straight-chain or branched-chain C3 to C5 alkyl, wherein the amount of said third monomer is preferably from about 3 mol % to about 30 mol %;
• and
• at the end of copolymerization, reacting the fluorocopolymer with methanol at a temperature that is greater than a copolymerization temperature to produce an endcapped fluorocopolymer containing ether end groups;
• and
• (ii) a carrier comprising one or more VOC compounds;
• wherein the coating composition comprises not greater than about 30% by weight of said carrier.