Composition including curable fluoropolymer and curative and methods of making and using them

Patent metadata

Field	Value
Publication number	US-12312426-B2
Application number	US-201917414280-A
Country	US
Kind code	B2
Filing date	Dec 17, 2019
Priority date	Dec 17, 2018
Publication date	May 27, 2025
Grant date	May 27, 2025

Abstract

The composition includes a curable fluoropolymer having nitrogen-containing cure sites and a curative including an organo onium cation and an anion represented by Formula (I) or Formula (II). The composition is free of metal cations or has not more than 20 parts per million metal cations and free of silicon dioxide or has less than 0.5 percent by weight silicon dioxide, based on the total weight of the composition. In some cases, the composition consists of the curable fluoropolymer and the curative. Shaped articles including the composition, a fluoroelastomer prepared by curing the composition, a method of making a fluoroelastomer article, and a process for making the composition are also described.

First claim

What is claimed is:

1. A composition comprising:
a curable fluoropolymer comprising nitrogen-containing cure sites and wherein the curable fluoropolymer comprises a partially fluorinated emulsifier and wherein the amount of partially fluorinated emulsifier is less than 500 ppb; and
a curative comprising an organo onium cation and an anion represented by Formula

wherein
each R and R′ is independently hydrogen, halogen, alkyl, aryl, arylalkylenyl, or alkylarylenyl, wherein the alkyl, aryl, arylalkylenyl, or alkylarylenyl each may be unsubstituted or each may be substituted by one or more halogens, with the proviso that R′ is not halogen, or R and R′ can join together to form a ring;
each Rf is RCF 2 — or a perfluoroalkyl group having up to 8 carbon atoms;
X is an organic linking group that is nonfluorinated or at least partially fluorinated; and n is 1 or 2,
wherein the composition is free of metal cations or comprises not more than 20 parts per million metal cations, and wherein the composition is free of silicon dioxide or comprises less than 0.5 percent by weight silicon dioxide, based on the total weight of the composition.

2. The composition of claim 1 , wherein if the composition comprises a fluorinated acid or salt thereof having 4 to 18 carbon atoms, the composition comprises not more than 2 ppm of the fluorinated acid or salt thereof.

3. The composition of claim 1 , wherein the curable fluoropolymer is an amorphous, curable fluoropolymer, and wherein the composition further comprises a partially crystalline fluoropolymer.

4. The composition of claim 1 , wherein the composition consists of:
the curable fluoropolymer comprising nitrogen-containing cure sites; and
the curative comprising an organo onium cation and an anion represented by Formula

wherein
each R and R′ is independently hydrogen, halogen, alkyl, aryl, arylalkylenyl, or alkylarylenyl, wherein the alkyl, aryl, arylalkylenyl, or alkylarylenyl each may be unsubstituted or each may be substituted by one or more halogens, with the proviso that R′ is not halogen, or R and R′ can join together to form a ring;
each Rf is RCF 2 — or a perfluoroalkyl group having up to 8 carbon atoms;
X is an organic linking group that is nonfluorinated or at least partially fluorinated; and n is 1 or 2.

5. The composition of claim 4 , wherein the curable fluoropolymer is an amorphous, curable fluoropolymer.

6. The composition of claim 3 , wherein the composition consists of:
the amorphous, curable fluoropolymer comprising nitrogen-containing cure sites;
the partially crystalline fluoropolymer; and
the curative comprising an organo onium cation and an anion represented by Formula

wherein
each R and R′ is independently hydrogen, halogen, alkyl, aryl, arylalkylenyl, or alkylarylenyl, wherein the alkyl, aryl, arylalkylenyl, or alkylarylenyl each may be unsubstituted or each may be substituted by one or more halogens, with the proviso that R′ is not halogen, or R and R′ can join together to form a ring;
each Rf is RCF 2 — or a perfluoroalkyl group having up to 8 carbon atoms;
X is an organic linking group that is nonfluorinated or at least partially fluorinated; and n is 1 or 2.

7. The composition of claim 6 , wherein each R is F, and wherein R′ is hydrogen, phenyl, methoxyphenyl, toluyl, fluorophenyl, trifluoromethylphenyl, or trifluoromethyl.

8. The composition of claim 6 , wherein the curable fluoropolymer comprises interpolymerized units of tetrafluoroethylene and at least one of a different perfluorinated olefin, a partially fluorinated olefin, a non-fluorinated olefin, a perfluoroalkylvinylether, or a perfluoroalkoxyalkylvinylether.

9. The composition of claim 8 , wherein the interpolymerized units further comprise at least one of perfluoro(8-cyano-5-methyl-3,6-dioxa-1-octene), CF 2 ═CFO(CF 2 ) L CN, CF 2 ═CFO(CF 2 ) u OCF(CF 3 )CN, CF 2 ═CFO[CF 2 CF(CF 3 )O] q (CF 2 O) y CF(CF 3 )CN, or CF 2 ═CF[OCF 2 CF(CF 3 )] r O(CF 2 ) t CN, wherein L is in a range from 2 to 12; u is in a range from 2 to 6; q is in a range from 0 to 4; y is in a range from 0 to 6; r is in a range from 1 to 2; and t is in a range from 1 to 4.

10. A fluoroelastomer prepared by curing the composition of claim 1 .

11. A method of making a fluoroelastomer article, the method comprising:
providing the composition of claim 1 ,
shaping the composition; and
crosslinking the composition to form the fluoroelastomer article.

12. The method of claim 11 , wherein crosslinking comprises heating the composition in an environment with a temperature set higher than 300° C.

13. A process for making the composition of claim 1 , the process comprising:
providing an aqueous composition containing particles of the curable fluoropolymer;
coagulating the curable fluoropolymer by at least one of contacting the aqueous composition with a mineral acid or by freeze coagulation;
isolating the curable fluoropolymer; and
combining the curable fluoropolymer with the curative.

14. The composition of claim 1 , wherein each R is F, and wherein R′ is hydrogen, phenyl, methoxyphenyl, toluyl, fluorophenyl, trifluoromethylphenyl, or trifluoromethyl.

15. The composition of claim 1 , wherein the organo onium cation is a tetraalkylphosphonium cation or a tetraalkylammonium cation.

16. The composition of claim 1 , wherein the curative is tetrabutylphosphonium 2-p-toluyl-1,1,1,3,3,3-hexafluoroisopropanolate.

17. The composition of claim 1 , wherein the curable fluoropolymer comprises interpolymerized units of tetrafluoroethylene and at least one of a different perfluorinated olefin, a partially fluorinated olefin, a non-fluorinated olefin, a perfluoroalkylvinylether, or a perfluoroalkoxyalkylvinylether.

18. The composition of claim 1 , wherein the composition comprises not more than 5 parts per million metal cations.

19. The composition of claim 1 , wherein the curable fluoropolymer is an amorphous, curable fluoropolymer, and wherein the composition further comprises (i) a melt-processable copolymer of TFE and perfluorinated ethers (PFA), (ii) a melt processable copolymer of TFE and HFP (FEP), (iii) partially crystalline polymers of TFE and ethylene (ET) (ETFE), (iv) tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride (THV), or (v) combinations thereof.

Assignees

• 3M Innovative Properties Company

Inventors

• Fukushi Tatsuo
• Aoki Tamon
• Chan Qilin
• Guerra Miguel A
• Hintzer Klaus
• Jochum Florian D
• Mitchell Michael H
• Sohlo Allen M
• Suzuki Yuta

Classifications

• C08F2810/20

  leading to a crosslinking, either explicitly or inherently · CPC title

• C08F2800/10

  as molar percentages · CPC title

• C08F214/262 Primary

  with fluorinated vinyl ethers · CPC title

• C08K5/50 Primary

  Phosphorus bound to carbon only · CPC title