Fluorine-containing copolymer composition, cross-linkable composition, and cross-linked rubber article

Abstract

Provided are a fluorine-containing copolymer composition capable of obtaining a crosslinkable composition that forms a crosslinked rubber article that is less likely to adhere to an object when combined with a crosslinking agent, and a crosslinked rubber article that is less likely to adhere to an object. A fluorine-containing copolymer composition comprising a fluorine-containing copolymer (A) having a tetrafluoroethylene-based unit and a perfluoro(alkyl vinyl ether)-based unit, and a fluorine-containing copolymer (B) that is different from the fluorine-containing copolymer (A) and has a unit based on a monomer having at least one functional group selected from the group consisting of a carboxyl group and a group represented by formula (X), a tetrafluoroethylene-based unit, and a perfluoro(alkyl vinyl ether)-based unit, and exhibits a prescribed storage elastic modulus. Formula (X) *‑CO‑O‑CO‑* In formula (X), * represents a bonding site.

Description

Technical Field

[0001] This invention relates to fluorinated copolymer compositions, crosslinking compositions, and crosslinked rubber articles. Background Technology

[0002] Based on their superior heat resistance, chemical resistance, oil resistance, and weather resistance, cross-linked rubber products made by cross-linking fluorinated copolymers are widely used as sealing materials (such as O-rings, gaskets, oil seals, and washers) and cushioning materials in vehicles, ships, aircraft, general machinery, construction, and other fields.

[0003] As a crosslinking composition for obtaining such crosslinked rubber articles, Patent Document 1 discloses a crosslinking composition comprising a specified fluorinated copolymer.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2021 / 210502 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] The inventors studied the properties of the composition described in Patent Document 1 and found that the cross-linked rubber article formed by the composition tends to adhere to the object, and therefore needs to be improved. For example, when the cross-linked rubber article obtained from the composition described in Patent Document 1 is used for an O-ring in a semiconductor device, if the movable components such as doors and covers of the semiconductor device tend to adhere to the O-ring, it will cause problems such as difficulty in opening doors and difficulty in moving the movable components.

[0009] The objective of this invention is to provide a fluorinated copolymer composition that can be obtained by combining a crosslinking composition capable of forming a crosslinked rubber article that is not easily fixed to an object with a crosslinking agent.

[0010] Furthermore, the subject of this invention is to provide crosslinking compositions and crosslinked rubber articles.

[0011] Solution for solving the problem

[0012] The inventors conducted in-depth research and found that the above-mentioned problems can be solved by the following configuration.

[0013] (1) A fluorinated copolymer composition comprising a fluorinated copolymer (A) and a fluorinated copolymer (B),

[0014] The aforementioned fluorinated copolymer (A) has tetrafluoroethylene-based units and perfluoro(alkyl vinyl ether)-based units.

[0015] The aforementioned fluorinated copolymer (B) is a fluorinated copolymer different from fluorinated copolymer (A), having units based on monomers having at least one functional group selected from the group consisting of a carboxyl group and a group represented by formula (X) described later, units based on tetrafluoroethylene, and units based on perfluorinated (alkyl vinyl ethers).

[0016] The fluorinated copolymer (A) and the fluorinated copolymer (B) constitute the test sample. The mass ratio of the content of fluorinated copolymer (B) in the test sample to the content of fluorinated copolymer (A) is the same as the mass ratio of the content of fluorinated copolymer (B) in the fluorinated copolymer composition to the content of fluorinated copolymer (A). The storage modulus of the test sample at 100°C is less than 650 kPa.

[0017] (2) The fluorinated copolymer composition according to (1), wherein the aforementioned fluorinated copolymer (A) comprises units having nitrile groups.

[0018] The content of units with nitrile groups is more than 0.14 mol% and less than 0.7 mol% relative to all units of the fluorinated copolymer (A).

[0019] (3) The fluorinated copolymer composition according to (1) or (2), wherein the content of units in the fluorinated copolymer (B) based on monomers having at least one functional group selected from the group consisting of carboxyl groups and groups represented by formula (X) is 0.01 to 3 mol% relative to all units of the fluorinated copolymer (B). The content of units based on tetrafluoroethylene is 90 to 99.89 mol% relative to all units of the fluorinated copolymer (B). The content of the aforementioned units based on perfluorinated (alkyl vinyl ether) is 0.1 to 9.99 mol% relative to all units of the fluorinated copolymer (B).

[0020] (4) The fluorinated copolymer composition according to any one of (1) to (3) further comprises the compound represented by formula (9) described below.

[0021] (5) The fluorinated copolymer composition according to (4), wherein the content of the compound represented by formula (9) is 0.1 to 5 parts by mass relative to 100 parts by mass of the fluorinated copolymer (A).

[0022] (6) The fluorinated copolymer composition according to any one of (1) to (5) further comprises a phosphorus compound having a melting point of less than 60°C.

[0023] (7) The fluorinated copolymer composition according to (6), wherein the content of phosphorus compound is 0.2 to 5 parts by mass relative to 100 parts by mass of fluorinated copolymer (A).

[0024] (8) The fluorinated copolymer composition according to any one of (1) to (7), wherein the content of the fluorinated copolymer (B) is 2 to 50 parts by mass relative to 100 parts by mass of the fluorinated copolymer (A).

[0025] (9) A crosslinking composition comprising any one of (1) to (8) a fluorinated copolymer composition, and further comprising a crosslinking agent.

[0026] (10) The crosslinking composition according to (9), wherein the crosslinking agent is a compound having two or more amino groups.

[0027] (11) The crosslinking composition according to (9) or (10), wherein the content of the crosslinking agent is 0.3 to 10 parts by weight relative to 100 parts by weight of the fluorinated copolymer (A).

[0028] (12) A crosslinking composition comprising a fluorinated copolymer (A), a fluorinated copolymer (B), and a crosslinking agent,

[0029] The aforementioned fluorinated copolymer (A) has tetrafluoroethylene-based units and perfluoro(alkyl vinyl ether)-based units.

[0030] The aforementioned fluorinated copolymer (B) is a fluorinated copolymer different from fluorinated copolymer (A), having units based on monomers having at least one functional group selected from the group consisting of a carboxyl group and a group represented by formula (X) described later, units based on tetrafluoroethylene, and units based on perfluorinated (alkyl vinyl ethers).

[0031] The recovery of cross-linked rubber articles obtained from the cross-linking composition after compression at 25% and 200°C for 70 hours is less than 80%.

[0032] Formula (X) *-CO-O-CO-*

[0033] In equation (X), * represents the bonding position.

[0034] (13) A cross-linked rubber article obtained from any one of (9) to (12).

[0035] The effects of the invention

[0036] According to the present invention, it is possible to provide a fluorinated copolymer composition that can be obtained by combining a crosslinking composition capable of forming a crosslinked rubber article that is not easily fixed to an object with a crosslinking agent.

[0037] In addition, the present invention can provide crosslinking compositions and crosslinked rubber articles. Detailed Implementation

[0038] The meanings of the terms used in this invention are as follows.

[0039] "Unit" refers to the atomic group directly formed by the polymerization of monomers, originating from one molecule of the aforementioned monomer, and the atomic group obtained by chemically transforming a portion of the aforementioned atomic group. "Monomer-based unit" is also referred to as "unit" below.

[0040] "Rubber" refers to rubber exhibiting the properties defined by JIS K 6200:2008, as opposed to "resin".

[0041] "Melting point" refers to the temperature corresponding to the maximum value of the melting peak as determined by differential scanning calorimetry (DSC).

[0042] "Boiling point" refers to the value determined according to the equilibrium reflux boiling point test method, specifically according to section 8.1 of JIS K2233:2017. If the pressure is specified after the boiling point, the boiling point recorded is the value measured at that pressure. Unless otherwise specified, the value obtained by converting the value measured according to section 8.1 of JIS K2233:2017 to the boiling point at 760 mmHg is the final value.

[0043] (Meth)acrylate is a general term for acrylates and methacrylates, and (meth)acryloyl is a general term for acryloyl and methacryloyl groups.

[0044] [Fluorine-containing copolymer composition]

[0045] The fluorinated copolymer composition of the present invention (hereinafter also referred to as "the composition") comprises a fluorinated copolymer (A) (hereinafter also referred to as "copolymer (A)") and a fluorinated copolymer (B) (hereinafter also referred to as "copolymer (B)"), wherein the fluorinated copolymer (A) has tetrafluoroethylene-based units and perfluoro(alkyl vinyl ether)-based units, and the fluorinated copolymer (B) is a different fluorinated copolymer from copolymer (A) having units based on monomers having at least one functional group selected from the group consisting of a carboxyl group and a group represented by formula (X) described later, tetrafluoroethylene-based units, and perfluoro(alkyl vinyl ether)-based units.

[0046] In addition, the energy storage modulus of this composition at 100°C is less than 650 kPa.

[0047] Crosslinked rubber articles obtained using a crosslinking composition containing the above-described composition and a crosslinking agent are not easily fixed to the target object.

[0048] The inventors have discovered that the aforementioned storage modulus is related to the adhesion of a crosslinked rubber article obtained from a crosslinking composition comprising the present composition and a crosslinking agent to a target object. Specifically, it has been found that when the aforementioned storage modulus is below a predetermined value, the crosslinked rubber article obtained from a crosslinking composition comprising the present composition and a crosslinking agent is less likely to adhere to the target object.

[0049] The details of the correlation described above are not yet clear, but it is speculated that the storage modulus is related to the dispersion state of copolymers (A) and (B). Furthermore, it is believed that due to their dispersion state, the resulting crosslinked rubber articles are prone to shrinkage during heating / cooling treatments. Therefore, it is speculated that if a crosslinked rubber article obtained from a crosslinking composition containing this composition and a crosslinking agent is subjected to heating and cooling treatments similar to those used with O-rings, when the dispersion state exhibits a specified storage modulus, the crosslinked rubber article is prone to shrinkage. Consequently, the contact area between the crosslinked rubber article and the target object is reduced, and the crosslinked rubber article is difficult to fix.

[0050] <Copolymer(A)>

[0051] This composition contains copolymer (A).

[0052] Copolymer (A) is a polymer having units based on tetrafluoroethylene (hereinafter also referred to as "TFE") and units based on perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PAVE"). Copolymer (A) itself cannot fully recover its elasticity when stretched, but through crosslinking, its recovery property is strengthened, thus exhibiting the properties of rubber.

[0053] From the viewpoint of achieving better results in this invention, the copolymer (A) preferably contains units having nitrile groups in addition to units based on TFE monomers and units based on PAVE monomers.

[0054] From the viewpoint of achieving better results from the present invention, the copolymer (A) preferably does not have units of a monomer having at least one functional group selected from the group consisting of a carboxyl group and a group represented by formula (X) described later.

[0055] The PAVE unit is based on perfluorinated (alkyl vinyl ether) units.

[0056] From the viewpoint of excellent polymerization reactivity and rubber properties, PAVE is preferably the monomer shown in formula (1).

[0057] CF2 = CF - OR f1 (1)

[0058] In equation (1), R f1 This refers to perfluoroalkyl groups with 1 to 10 carbon atoms. From the perspective of superior polymerization reactivity, R... f1The number of carbon atoms is preferably 1 to 8, more preferably 1 to 6, even more preferably 1 to 5, and particularly preferably 1 to 3.

[0059] Perfluoroalkyl groups can be linear or branched.

[0060] Specific examples of PAVE include perfluoro(methyl vinyl ether) (hereinafter also referred to as "PMVE"), perfluoro(ethyl vinyl ether) (hereinafter also referred to as "PEVE"), and perfluoro(propyl vinyl ether) (hereinafter also referred to as "PPVE"), wherein PMVE and PPVE are preferred.

[0061] The unit having a nitrile group is based on a monomer having a nitrile group (hereinafter also referred to as "R"). CN The unit of "). From the viewpoint of achieving better results in this invention, R CN Preferably, it has fluorine atoms, and particularly preferably the monomer shown in formula (2).

[0062] CR 21 R 22 =CR 23 -R 24 -CN (2)

[0063] In equation (2), R 21 R 22 and R 23 Each can independently represent a hydrogen atom, a fluorine atom, or a methyl group, R 24 It refers to a perfluorocarbon group with 1 to 10 carbon atoms in a divalent state, or a group having an ether-like oxygen atom at the end of the perfluorocarbon group or between carbon-carbon bonds.

[0064] From R CN Based on the viewpoint of excellent polymerization reactivity, R is preferred. 21 R 22 R 23 It is a fluorine atom or a hydrogen atom, more preferably R 21 R 22 R 23 From the viewpoint that cross-linked rubber articles are composed entirely of fluorine atoms or entirely of hydrogen atoms, R is particularly preferred due to its superior release properties and heat resistance. 11 R 12 R 13 It consists entirely of fluorine atoms.

[0065] R 24 It can be any of the following: linear, branched, or cyclic, preferably linear or branched. 24 The number of carbon atoms is preferably 2 to 8, more preferably 3 to 7, even more preferably 3 to 6, and particularly preferably 3 to 5.

[0066] R 24It may be optional to have ether-containing oxygen atoms, but from the viewpoint that the crosslinked rubber articles obtained from the crosslinking composition containing the present composition and the crosslinking agent have superior rubber properties, it is preferred to have ether-containing oxygen atoms.

[0067] R 24 The number of ether oxygen atoms in the sample is preferably 1 to 3, and particularly preferably 1 or 2.

[0068] Specific examples of the monomers shown in formula (2) include CF2=CFOCF2CF(CF3)OCF2CF2CN (hereinafter also referred to as "8CNVE"), CF2=CFO(CF2)5CN (hereinafter also referred to as "MV5CN"), CF2=CFOCF2CF2CF2OCF(CF3)CN, and CF2=CFO(CF2)3CN. From the viewpoint that the crosslinked rubber articles have better release properties and heat resistance, 8CNVE and MV5CN are preferred.

[0069] The copolymer (A) may also have units based on monomers other than those described above (hereinafter also referred to as "other monomers"). Specific examples of other monomers include vinylidene fluoride (hereinafter also referred to as "VdF"), hexafluoropropylene (hereinafter also referred to as "HFP"), trifluorochloroethylene, monomers having two or more polymerizable unsaturated bonds (hereinafter also referred to as "BO"), monomers shown in formula (6), ethylene, and propylene. In addition, monomers having halogen atoms (hereinafter also referred to as "monomers having other halogen atoms") (e.g., bromotrifluoroethylene, iodotrifluoroethylene) may also be mentioned as monomers other than those described above.

[0070] The BO unit is a unit based on monomers having two or more polymerizable unsaturated bonds.

[0071] Specific examples of polymerizable unsaturated bonds include carbon-carbon double bonds (C=C) and carbon-carbon triple bonds (C≡C).

[0072] The number of polymerizable unsaturated bonds in BO is preferably 2 to 6, which gives it better polymerization reactivity; more preferably 2 or 3; and particularly preferably 2.

[0073] BO also contains fluorine atoms.

[0074] The monomer shown in BO preferred formula (3).

[0075] (CR 31 R 32 =CR 33 ) a3 R 34 (3)

[0076] In equation (3), R 31 R 32and R 33 Each of these elements independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; a3 represents an integer from 2 to 6; R 34 This refers to a perfluorocarbon group with 1 to 10 carbon atoms in the α3 valence, or a group having an ether-like oxygen atom at the end of the perfluorocarbon group or between carbon-carbon bonds. Multiple R 31 Multiple R 32 and multiple R 33 Each can choose to be the same as or different from the others, with a preference for them to be the same.

[0077] a3 is preferably 2 or 3, and particularly preferably 2.

[0078] From the perspective that BO has superior polymerization reactivity, R is preferred. 31 R 32 R 33 It is a fluorine atom or a hydrogen atom, more preferably R 31 R 32 R 33 Composed entirely of fluorine or hydrogen atoms, R is particularly preferred from the perspective of the heat resistance and chemical resistance of cross-linked rubber articles. 31 R 32 R 33 It consists entirely of fluorine atoms.

[0079] R 34 It can be any of the following: linear, branched, or cyclic, preferably linear or branched, and particularly preferably linear. R 34 The number of carbon atoms is preferably 2 to 10, more preferably 3 to 8, even more preferably 3 to 6, and particularly preferably 3 to 5.

[0080] R 34 From the perspective of superior crosslinking reactivity and rubber properties, oxygen atoms with ether properties are preferred.

[0081] R 34 The number of ether-containing oxygen atoms is preferably 1 to 6, more preferably 1 to 3, and particularly preferably 1 or 2. R 34 The ether oxygen atom in R is preferably present in R 34 The end of.

[0082] Among the monomers shown in formula (3), specific examples of preferred monomers include the monomers shown in formula (4) and the monomers shown in formula (5).

[0083] (CF2=CF)2R 41 (4)

[0084] In equation (4), R 41It refers to a perfluorocarbon group with 2 to 10 carbon atoms in a divalent state, or a group having an ether-like oxygen atom at the end of the perfluorocarbon group or between carbon-carbon bonds.

[0085] Specific examples of the monomers shown in equation (4) include CF2=CFO(CF2)2OCF=CF2, CF2=CFO(CF2)3OCF=CF2 (hereinafter also referred to as "C3DVE"), CF2=CFO(CF2)4OCF=CF2, CF2=CFO(CF2)6OCF=CF2, CF2=CFO(CF2)8OCF=CF2, CF2=CFO(CF2)2OCF(CF3)CF2OCF=CF2, CF2 =CFO(CF2)2O(CF(CF3)CF2O)2CF=CF2, CF2=CFOCF2O(CF2CF2O)2CF=CF2, CF2=CFO(CF2O)3O(CF(CF3)CF2O )2CF=CF2, CF2=CFOCF2CF(CF3)O(CF2)2OCF(CF3)CF2OCF=CF2, CF2=CFOCF2CF2O(CF2O)2CF2CF2OCF=CF2.

[0086] Among the monomers shown in equation (4), specific examples of more preferred monomers include CF2=CFO(CF2)3OCF=CF2 and CF2=CFO(CF2)4OCF=CF2.

[0087] (CH2=CH)2R 51 (5)

[0088] In equation (5), R 51 It refers to a perfluorocarbon group with 2 to 10 carbon atoms in a divalent state, or a group having an ether-like oxygen atom at the end of the perfluorocarbon group or between carbon-carbon bonds.

[0089] Specific examples of the monomers shown in equation (5) include CH2=CH(CF2)2CH=CH2, CH2=CH(CF2)4CH=CH2, and CH2=CH(CF2)6CH=CH2.

[0090] Among the monomers shown in equation (5), CH2=CH(CF2)6CH=CH2 is a more preferred example.

[0091] If BO is copolymerized, the polymerizable double bonds at the ends of BO react during polymerization to obtain a branched copolymer (A).

[0092] Equation (6) is as follows.

[0093] CF2 = CF - OR f6 (6)

[0094] In equation (6), R f6 R represents a perfluoroalkyl group with 1 to 8 carbon atoms and containing 1 to 5 ether-containing oxygen atoms. f6 The number of carbon atoms is preferably 1 to 6, and particularly preferably 1 to 5.

[0095] Specific examples of the monomers shown in formula (6) include perfluorinated (3,6-dioxa-1-heptene), perfluorinated (3,6-dioxa-1-octene), and perfluorinated (5-methyl-3,6-dioxa-1-nonene).

[0096] From the viewpoint of achieving better results with the present invention, the content of TFE units relative to all units of copolymer (A) is preferably 60 to 68 mol%, more preferably 62 to 67%, particularly preferably 63 to 67 mol%, and most preferably 64 to 66 mol%. Furthermore, if the content of TFE units is within the above range, it is easy to adjust the storage modulus of the fluorinated copolymer composition at 100°C to 650 kPa or less.

[0097] From the viewpoint of achieving better results with the present invention, the content of PAVE units relative to all units of copolymer (A) is preferably 32 to 40 mol%, more preferably 33 to 38 mol%, particularly preferably 33 to 37 mol%, and most preferably 34 to 36 mol%. When PMVE or PPVE is used as PAVE, the preferred content is also the same.

[0098] From the viewpoint of superior performance of the present invention, copolymer (A) contains R CN The content of the unit relative to all units of the copolymer (A) is preferably 0.05 to 5 mol%, more preferably 0.1 to 3 mol%, and particularly preferably 0.2 to 1.5 mol%.

[0099] From the viewpoint of achieving better results from the present invention, the content of the fluorinated copolymer containing other monomer units relative to all units of the fluorinated copolymer is preferably 0.01 to 20 mol%, more preferably 0.5 to 10 mol%, and particularly preferably 1 to 5 mol%.

[0100] In the fluorinated copolymer (A), R CN The content of the unit relative to all units of the copolymer (A) is preferably 0.14 mol% or more and less than 0.7 mol%.

[0101] From the viewpoint of achieving better results in this invention, copolymer (A) is preferably a perfluoropolymer.

[0102] Here, "perfluoropolymer" refers to a polymer that substantially does not contain hydrogen atoms bonded to carbon atoms, but instead has fluorine atoms, and whose main chain is composed of carbon atoms. The side chains of perfluoropolymers may have multivalent atoms other than carbon atoms, with oxygen atoms being preferred.

[0103] Here, "substantially contains no hydrogen atoms" means that the hydrogen atom content in the perfluoropolymer is 0.5% by mass or less, preferably 0.1% by mass or less, more preferably 0.07% by mass or less, and particularly preferably 0.05% by mass or less. If the hydrogen atom content is within the above range, good heat resistance or chemical resistance can be easily obtained.

[0104] The copolymer (A) may contain iodine atoms. In this case, it is preferable to have iodine atoms at the ends of the polymer chains of the copolymer (A).

[0105] Examples of iodine atoms include iodine atoms derived from iodine compounds that function as chain transfer agents (described later), and iodine atoms in units of monomers containing iodine atoms, such as iodotrifluoroethylene, which have other halogen atoms. Iodine atoms derived from iodine compounds that function as chain transfer agents are preferred.

[0106] The content of iodine atoms in copolymer (A) relative to the total mass of copolymer (A) is preferably 0.01 to 5.0% by mass, more preferably 0.05 to 2.0% by mass, and particularly preferably 0.05 to 1.0% by mass. If the content of iodine atoms is within the above range, the crosslinking reactivity of copolymer (A) is improved, and the mechanical properties of the crosslinked rubber article are excellent.

[0107] The content of copolymer (A) relative to the total mass of the composition is preferably 60 to 99% by mass, more preferably 70 to 95% by mass, and particularly preferably 80 to 90% by mass.

[0108] (Method for manufacturing copolymer (A))

[0109] As an example of a method for manufacturing copolymer (A), one can cite a method of copolymerizing the above monomers in the presence of a free radical polymerization initiator.

[0110] As free radical polymerization initiators, water-soluble polymerization initiators and redox polymerization initiators are preferred. Specific examples of water-soluble polymerization initiators include persulfate-based initiators such as ammonium persulfate, sodium persulfate, and potassium persulfate; and organic polymerization initiators such as disuccinic acid peroxide and azobisisobutylamidine dihydrochloride. Among these, persulfate-based initiators are preferred, and ammonium persulfate is particularly preferred.

[0111] Examples of redox polymerization initiators include polymerization initiators composed of persulfates and reducing agents. Among these, polymerization initiators capable of polymerizing monomers within a polymerization temperature range of 0 to 85°C are preferred. Specific examples of persulfates constituting redox polymerization initiators include alkali metal salts of persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate, with ammonium persulfate being the most preferred. Specific examples of reducing agents combined with persulfates include thiosulfates, sulfites, bisulfites, metabisulfites, and hydroxymethanesulfinates, with hydroxymethanesulfinates being the most preferred, and sodium hydroxymethanesulfinate being particularly preferred.

[0112] In the method for manufacturing copolymer (A), the monomers described above can be copolymerized together with a free radical polymerization initiator in the presence of a chain transfer agent.

[0113] The chain transfer agent is preferably an iodine compound, and particularly preferably an iodine compound represented by the formula RI2. In the above formula, R represents an alkylene group or a perfluoroalkylene group having 3 or more carbon atoms (preferably 3 to 8 carbon atoms).

[0114] Specific examples of iodine compounds represented by formula RI2 include 1,3-diiodopropane, 1,4-diiodobutane, 1,6-diiodohexane, 1,8-diiodooctane, 1,3-diiodoperfluoropropane, 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, and 1,8-diiodoperfluorooctane.

[0115] As an iodine compound, an iodine compound having a perfluoroalkylene group is preferred, and 1,4-diiodoperfluorobutane is particularly preferred.

[0116] When the monomers are copolymerized in the presence of these iodine compounds, iodine atoms can be introduced into the copolymer (A).

[0117] For details regarding the other components used in the manufacture of copolymer (A) and the manufacturing method, please refer to the methods described in paragraphs 0019 to 0034 of International Publication No. 2010 / 082633.

[0118] <Copolymer(B)>

[0119] This composition contains copolymer (B).

[0120] The copolymer (B) is a monomer (hereinafter also referred to as "R") having at least one functional group (hereinafter also referred to as "specific functional group") based on a group having a carboxyl group and a group represented by formula (X). X Polymers of TFE and PAVE units.

[0121] Formula (X) *-CO-O-CO-*

[0122] In equation (X), * represents the bonding position.

[0123] R X It can have multiple specific functional groups. R X In the case of having multiple specific functional groups, the types of the multiple specific functional groups can be chosen to be the same or different from each other.

[0124] R X As a monomer, it therefore possesses polymerizable unsaturated bonds. Specific examples of polymerizable unsaturated bonds are described above.

[0125] R X Preferably, it is a compound having one specific functional group and one polymerizable unsaturated bond.

[0126] Examples of unsaturated dicarboxylic acids with carboxyl groups include itaconic acid, citraconic acid, 5-norbornene-2,3-dicarboxylic acid, and maleic acid; unsaturated monocarboxylic acids include acrylic acid and methacrylic acid; CF2=CFOR fx CO2H (wherein, R) fx (Optionally, a perfluoroalkylene group having 1 to 10 carbon atoms and an ether-containing oxygen atom).

[0127] As a group containing the group shown in formula (X), it is preferred to be a group formed by removing one hydrogen atom from an acid anhydride.

[0128] Examples of monomers having the group shown in formula (X) include itaconic anhydride (hereinafter also called "IAH"), citraconic anhydride (hereinafter also called "CAH"), 5-norbornene-2,3-dicarboxylic anhydride (also called nadic anhydride, hereinafter also called "NAH"), maleic anhydride, and other anhydrides of unsaturated dicarboxylic acids.

[0129] From the viewpoint of reactivity with the nitrile groups of copolymer (A), R X Preferably, the monomer has a group shown in formula (X). From the viewpoint of making the manufacture of copolymer (B) easier, it is more preferable to include at least one selected from the group consisting of IAH, CAH and NAH, and particularly preferably includes NAH.

[0130] R X You can use one type alone, or you can use two or more types together.

[0131] The specific examples and preferred embodiments of the PAVE units in copolymer (B) are the same as those in copolymer (A).

[0132] The copolymer (B) may have units based on monomers other than those described above (hereinafter also referred to as "other monomers"). Specific examples and preferred embodiments of the other monomers are the same as those of the other monomers in the copolymer (A).

[0133] The copolymer (B) can have specific functional groups as terminal groups of the main chain. These functional groups can be introduced by appropriately selecting the free radical polymerization initiator, chain transfer agent, etc. used in the manufacture of the copolymer (B).

[0134] From the viewpoint of achieving better results with the present invention, the content of the unit having a specific functional group relative to all units of the copolymer (B) is preferably 0.01 to 3 mol%, more preferably 0.03 to 2 mol%, and particularly preferably 0.05 to 1 mol%. When NAH is used as the unit having a specific functional group, the preferred range is also the same.

[0135] Furthermore, from the viewpoint of achieving better results with the present invention, the content of TFE units relative to all units of the copolymer (B) is preferably 90 to 99.89 mol%, more preferably 95 to 99.47 mol%, and particularly preferably 96 to 98.95 mol%.

[0136] Furthermore, from the viewpoint of achieving better results with the present invention, the content of PAVE units relative to all units of copolymer (B) is preferably 0.1 to 9.99 mol%, more preferably 0.5 to 4.97 mol%, and particularly preferably 1 to 3.95 mol%. The preferred range is also the same when PPVE units are used as PAVE units.

[0137] From the viewpoint of achieving better results from the present invention, the content of copolymer (B) relative to 100 parts by mass of copolymer (A) is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, further preferably 25 parts by mass or less, and particularly preferably 20 parts by mass or less.

[0138] From the viewpoint of achieving better results from the present invention, the content of copolymer (B) relative to 100 parts by mass of copolymer (A) is preferably 0.5 parts by mass or more, more preferably 2 parts by mass or more, further preferably 5 parts by mass or more, and particularly preferably 7 parts by mass or more.

[0139] In addition, if the content of copolymer (B) is within the above range, it is easy to adjust the storage modulus of the fluorinated copolymer composition at 100°C to below 650 kPa.

[0140] The melting point of copolymer (B) is preferably 260~320°C, more preferably 280°C~315°C, and particularly preferably 295~310°C. If the melting point of copolymer (B) is above or below the lower limit of the above range, the crosslinked rubber article obtained from the crosslinking composition containing the present composition including copolymer (B) and the crosslinking agent has excellent heat resistance; if it is below or below the upper limit of the above range, it has excellent processability, and the crosslinked rubber article obtained from the crosslinking composition containing the present composition including copolymer (B) and the crosslinking agent has excellent surface smoothness.

[0141] The melting point of copolymer (B) can be adjusted by the types, proportions, and molecular weight of the units that make up copolymer (B). For example, the higher the proportion of TFE units, the higher the melting point of copolymer (B) tends to be.

[0142] (Method for manufacturing copolymer (B))

[0143] As an example of a method for manufacturing copolymer (B), one can cite a method for copolymerizing the above monomers in the presence of a free radical polymerization initiator, the details of which are described in International Publication No. 2016 / 017801.

[0144] (form)

[0145] The copolymer (B) is preferably contained in the composition in the form of particles. That is, the copolymer (B) is preferably contained in the composition in the form of resin particles containing the copolymer (B).

[0146] The resin particles may contain resins other than copolymers (A) and copolymers (B) (hereinafter also referred to as "other resins"). Examples of other resins include fluorinated copolymers other than copolymers (A) and copolymers (B) described below (e.g., tetrafluoroethylene-fluoroalkyl vinyl ether copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, ethylene-tetrafluoroethylene copolymers, etc.), polytetrafluoroethylene, aromatic polyesters, polyamide-imides, and thermoplastic polyimides.

[0147] The content of copolymer (B) in the resin particles is preferably 80 to 100% by mass relative to the total mass of the resin particles, more preferably 85 to 100% by mass, further preferably 90 to 100% by mass, and particularly preferably 100% by mass.

[0148] From the viewpoint of achieving better results with the present invention, the average particle size of the resin particles is preferably 0.02 to 50 μm, more preferably 0.02 to 35 μm, and particularly preferably 0.02 to 10 μm.

[0149] The average particle size of the resin particles is the cumulative 50% diameter (D50) of the volume reference obtained by laser diffraction and scattering. That is, the particle size distribution is determined by laser diffraction and scattering, and the cumulative curve is obtained by setting the total volume of the particle group to 100%. The particle size at the point where the cumulative volume is 50% on the cumulative curve is the particle size.

[0150] Resin particles can be manufactured, for example, by the method for manufacturing resin particles and resin powder described in International Publication No. 2016 / 017801.

[0151] <Specific phosphorus compounds>

[0152] From the viewpoint of achieving better results from the present invention, the composition preferably contains a phosphorus compound with a melting point of 60°C or below (hereinafter also referred to as "specific phosphorus compound").

[0153] The melting point of the specific phosphorus compound is below 60°C. From the viewpoint of further improving the dispersibility of the specific phosphorus compound and enhancing the effect of the present invention, it is preferably below 35°C, and particularly preferably below 20°C.

[0154] It should be noted that the above-mentioned compounds with melting points below a specific temperature also include compounds that are liquid at 20°C.

[0155] From the viewpoint of ease of handling, the boiling point of a particular phosphorus compound is preferably 50°C or higher, and more preferably 100°C or higher.

[0156] From the viewpoint of achieving better results from the present invention, the specific phosphorus compound is preferably a phosphine or phosphine oxide having an alkyl group, more preferably a trialkylphosphine or trialkylphosphine oxide, further preferably a compound represented by formula (7) or formula (8), and particularly preferably a compound represented by formula (7).

[0157] P(R 71 Formula (7)

[0158] In equation (7), R 71 Represents a straight-chain or branched alkyl group with 2 to 9 carbon atoms. (3 Rs) 71 They can be either the same or different, but the same is preferred.

[0159] PO(R 81 Formula (8)

[0160] In equation (8), R 81 Represents a straight-chain or branched alkyl group with 2 to 9 carbon atoms. (3 Rs) 81 They can be either the same or different, but the same is preferred.

[0161] R 71 The number of carbon atoms is 2 to 9, preferably 4 to 9, and particularly preferably 6 to 8.

[0162] 3 Rs 71 Each is preferably a straight-chain alkyl group having 2 to 9 carbon atoms.

[0163] R 81 The number of carbon atoms is 2 to 9, preferably 4 to 9, and particularly preferably 6 to 8.

[0164] 3 Rs 81 Each is preferably a straight-chain alkyl group having 2 to 9 carbon atoms.

[0165] Specific examples of the compounds shown in formula (7) include triethylphosphine (melting point -86°C, liquid at 20°C, boiling point 127~128°C), tri-n-propylphosphine (melting point unknown, liquid at 20°C, boiling point 72~74°C / 12mmHg), tri-n-butylphosphine (melting point -65°C, liquid at 20°C, boiling point 150°C / 50mmHg), tri-tert-butylphosphine (melting point 30~35°C, liquid or solid at 20°C, boiling point 102°C / 13mmHg), tri-n-pentylphosphine (melting point unknown, liquid at 20°C, boiling point unknown), tri-n-hexylphosphine (melting point unknown, liquid at 20°C, boiling point 227°C / 50mmHg), and tri-n-octylphosphine (melting point unknown, liquid at 20°C, boiling point 175°C / 0.3mmHg).

[0166] Specific examples of the compounds shown in formula (8) include triethylphosphine oxide (melting point 52°C, solid at 20°C), tri-n-propylphosphine oxide (melting point 39°C, solid at 20°C), tri-n-hexylphosphine oxide (melting point 34°C, solid at 20°C), and tri-n-octylphosphine oxide (melting point 52°C, solid at 20°C).

[0167] Among specific phosphorus compounds, tri-n-octylphosphine is preferred.

[0168] From the viewpoint that the generation of cracks in crosslinked rubber articles obtained from crosslinked compositions comprising the present composition and a crosslinking agent can be further suppressed, the content of the specific phosphorus compound is preferably 0.01 parts by mass or more, more preferably 0.10 parts by mass or more, relative to 100 parts by mass of copolymer (A), and is further preferably 0.20 parts by mass or more, from the viewpoint that the crosslinked rubber articles obtained from crosslinked compositions comprising the present composition and a crosslinking agent have excellent demolding properties.

[0169] From the viewpoint of achieving better results from the present invention, the content of the specific phosphorus compound relative to 100 parts by mass of copolymer (A) is preferably 5 parts by mass or less, more preferably 2 parts by mass or less, and even more preferably 1.0 parts by mass or less.

[0170] <The compound shown in formula (9)>

[0171] This composition preferably includes the compound shown in formula (9).

[0172] H2C=CH-R 91 -R 93 -R 92 -CH=CH2 Equation (9)

[0173] R 91 and R 92 Each can be independently represented as CH2 or CF2, preferably CH2.

[0174] R93 It refers to a fluorocarbon group with 1 to 10 carbon atoms in a divalent state, or a group having an ether-like oxygen atom at the end of the fluorocarbon group or between carbon-carbon bonds.

[0175] The fluoroalkyl group can be any of the following: linear, branched, or cyclic, preferably linear or branched, and particularly preferably linear. R 93 The number of carbon atoms is preferably 2 to 10, more preferably 3 to 8, even more preferably 3 to 6, and particularly preferably 3 to 5.

[0176] The fluorocarbon group is preferably a perfluorocarbon group.

[0177] From the viewpoint of achieving better results in this invention, the content of the compound shown in formula (9) is preferably 0.1 to 5 parts by mass relative to 100 parts by mass of copolymer (A), and more preferably 1 to 3 parts by mass.

[0178] <Other Ingredients>

[0179] This composition may contain other components besides those described above without impairing the effects of the present invention. Examples of other components include acid absorbents (e.g., fatty acid esters, fatty acid metal salts, oxides of divalent metals (magnesium oxide, calcium oxide, zinc oxide, lead oxide, etc.)), fillers and reinforcing materials (e.g., carbon black, barium sulfate, calcium metasilicate, calcium carbonate, titanium dioxide, silica, fluorinated copolymers other than copolymers (A) and (B) (e.g., tetrafluoroethylene-fluoroalkyl vinyl ether copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, ethylene-tetrafluoroethylene copolymers, etc.), polytetrafluoroethylene (PTFE), aromatic polyesters, polyamide-imides and thermoplastic polyimides, clay, talc), scorch inhibitors (e.g., compounds containing phenolic hydroxyl groups such as bisphenol A, quinones such as hydroquinone, α-methylstyrene dimers such as 2,4-di(3-isopropylphenyl)-4-methyl-1-pentene), crown ethers (e.g., 18-crown-6), and release agents (e.g., sodium stearate).

[0180] When the composition contains other components, the total content of the other components is preferably more than 0.1 parts by weight and less than 30 parts by weight relative to 100 parts by weight of copolymer (A), more preferably 1 to 15 parts by weight, and particularly preferably 3 to 5 parts by weight.

[0181] However, this composition does not contain a crosslinking agent.

[0182] As described below, a crosslinkable composition can be obtained by combining this composition with a crosslinking agent.

[0183] As a method for preparing this composition, one example is the mixing of the above-mentioned components. The mixing of the components can be carried out using rubber mixing equipment such as rollers, kneaders, Banbury mixers, or extruders.

[0184] Alternatively, the mixture obtained by mixing the above-mentioned components can be molded. Specific examples of molding methods for the mixture include compression molding, injection molding, extrusion molding, calendering, or molding by dissolving in a solvent and impregnating or coating onto a substrate.

[0185] <Storage Modulus>

[0186] This composition exhibits the specified energy storage modulus.

[0187] As a measuring device, any device capable of measuring the storage modulus can be used, such as PREMERRPA (manufactured by Alpha Technologies, die shape: D0380).

[0188] When performing the test, it is preferable to use a sheet-like sample of this composition (approximately 3 mm thick).

[0189] As a measurement step, the sheet-like composition was held at 100°C, a frequency of 30 cpm, and an amplitude angle of 0.2 degrees for 2 minutes. Then, the amplitude angle was set to 0.5 degrees, and the frequency was increased to 10 cpm, 20 cpm, and 50 cpm. The storage modulus at the frequency of 50 cpm when the storage modulus was measured was taken as the storage modulus of the composition.

[0190] The energy storage modulus of this composition at 100°C is less than 650 kPa. From the viewpoint of achieving better results from the present invention, it is preferably 50 to 600 kPa, and particularly preferably 400 to 600 kPa.

[0191] [Crosslinking composition (first embodiment)]

[0192] The crosslinking composition of the first embodiment of the present invention (hereinafter also referred to as "this crosslinking composition 1") is obtained by combining the composition with a crosslinking agent. That is, this crosslinking composition 1 is a crosslinking composition that includes the composition and also includes a crosslinking agent.

[0193] The composition of this composition is as described above.

[0194] Crosslinking agent

[0195] Specific examples of crosslinking agents contained in this crosslinking composition 1 include organic peroxides and compounds having two or more amino groups (hereinafter also referred to as "polyamine compounds"). From the viewpoint of excellent crosslinking properties of copolymer (A), polyamine compounds are preferred.

[0196] The polyamine compound can be a compound in which hydrogen atoms of aliphatic hydrocarbons are replaced by amino groups, or a compound in which hydrogen atoms of aromatic hydrocarbons are replaced by amino groups. From the viewpoint of achieving better results in this invention, a compound in which hydrogen atoms of aromatic hydrocarbons are replaced by amino groups is preferred.

[0197] The polyamine compound preferably contains fluorine atoms. This results in good compatibility with the copolymer (A).

[0198] Specific examples of polyamine compounds include hexamethylenediamine, hexamethylenediamine carbamate, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (hereinafter also called "BOAP", alternative name, bisaminophenol AF), 2,2-bis(3,4-diaminophenyl)propane, 2,2-bis(3,4-diaminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-(N-phenylamino)phenyl)hexafluoropropane, 4,4'-methylenediphenylamine, m-phenylenediamine, adipic acid dihydrazide, and compounds of formula (XII) in Japanese Patent No. 5833657. Of these, BOAP is preferred from the viewpoint of superior efficacy of the present invention.

[0199] The content of the crosslinking agent in this crosslinking composition 1 is preferably 0.3 to 10 parts by weight relative to 100 parts by weight of copolymer (A), more preferably 0.3 to 5 parts by weight, and particularly preferably 0.5 to 3 parts by weight. If the content of the crosslinking agent is within the above range, the effects of the present invention are even better.

[0200] [Crosslinking composition (Second embodiment)]

[0201] The crosslinking composition of the second embodiment of the present invention (hereinafter also referred to as "this crosslinking composition 2") comprises copolymer (A), copolymer (B), and crosslinking agent.

[0202] Furthermore, in this crosslinking composition 2, the recovery of the crosslinked rubber article obtained from this crosslinking composition 2 after compression at 200°C for 70 hours under 25% compression conditions is less than 80%.

[0203] Crosslinked rubber articles obtained using the above-described crosslinking composition 2 are not easily fixed to the target object.

[0204] The detailed reasons for achieving the desired effect through the composition of this crosslinking composition 2 are not yet clear. However, if the resilience of the crosslinked rubber article obtained from this crosslinking composition 2 containing the specified components is less than a specified value, it tends to return to its state before the pressure was applied when the pressure applied to the crosslinked rubber article is released. It is speculated that when a crosslinked rubber article exhibiting such characteristics is used in a pressure-applied component such as an O-ring, it tends to return to its original state when the pressure is released, thus reducing the portion of the crosslinked rubber article in contact with the object and making it less likely to adhere.

[0205] The definitions and preferred methods of copolymer (A), copolymer (B) and crosslinking agent contained in this crosslinking composition 2 are the same as those described in this composition and this crosslinking composition 1.

[0206] The content of copolymer (A) in this crosslinking composition 2 is preferably 60 to 99% by mass relative to the total mass of this crosslinking composition 2, more preferably 70 to 95% by mass, and particularly preferably 80 to 90% by mass.

[0207] From the viewpoint of achieving better results from the present invention, the content of copolymer (B) in the crosslinking composition 2 is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less, relative to 100 parts by mass of copolymer (A).

[0208] From the viewpoint of achieving better results from the present invention, the content of copolymer (B) in the crosslinking composition 2 is preferably 0.5 parts by mass or more, more preferably 2 parts by mass or more, further preferably 5 parts by mass or more, and particularly preferably 7 parts by mass or more, relative to 100 parts by mass of copolymer (A).

[0209] The content of the crosslinking agent in this crosslinking composition 2 is preferably 0.3 to 10 parts by weight relative to 100 parts by weight of copolymer (A), more preferably 0.3 to 5 parts by weight, and particularly preferably 0.5 to 3 parts by weight. If the content of the crosslinking agent is within the above range, the effects of the present invention are even better.

[0210] This crosslinking composition 2 may also contain components other than copolymer (A), copolymer (B) and crosslinking agent. Examples of such components include specific phosphorus compounds, compounds represented by formula (9), and the aforementioned "other components".

[0211] From the viewpoint that it can further suppress the generation of cracks in the crosslinked rubber article obtained from the present crosslinking composition 2, the content of the specific phosphorus compound in the present crosslinking composition 2 is preferably 0.01 parts by mass or more, more preferably 0.10 parts by mass or more, relative to 100 parts by mass of copolymer (A), and is even more preferably 0.20 parts by mass or more, from the viewpoint that the crosslinked rubber article obtained from the present crosslinking composition 2 has excellent demolding properties.

[0212] From the viewpoint of achieving better results from the present invention, the content of the specific phosphorus compound in the crosslinking composition 2 is preferably 5 parts by mass or less, more preferably 2 parts by mass or less, and even more preferably 1.0 parts by mass or less, relative to 100 parts by mass of copolymer (A).

[0213] From the viewpoint of achieving better results in this invention, the content of the compound represented by formula (9) in this crosslinking composition 2 is preferably 0.1 to 5 parts by mass relative to 100 parts by mass of copolymer (A), more preferably 1 to 3 parts by mass.

[0214] When the crosslinking composition 2 contains the above-mentioned "other components", the total content of the other components is preferably more than 0.1 parts by mass and less than 30 parts by mass relative to 100 parts by mass of copolymer (A), more preferably 1 to 15 parts by mass, and particularly preferably 3 to 5 parts by mass.

[0215] The recovery of the crosslinked rubber article obtained from this crosslinking composition 2 after compression at 200°C for 70 hours at a compression rate of 25% in the recovery force test is less than 80%. From the viewpoint of further improving the effect of the present invention, it is preferable to be 60% or less, and particularly preferably 50% or less. It should be noted that the lower limit of recovery is 0%.

[0216] The aforementioned resilience varies depending on the content ratio of copolymer (A) and copolymer (B), the content of each unit in copolymer (A) and copolymer (B), and the content and type of crosslinking agent.

[0217] Specifically, as a method for determining the aforementioned resilience, in an oven, a cross-linked rubber article is compressed at 200°C for 70 hours with a compression ratio of 25% using a clamp. The sample is then removed from the oven and placed at room temperature for 24 hours while still held in the clamp. The clamp is then removed, and the thickness of the test piece is measured after 30 minutes. The resilience (%) is evaluated using the recovery rate calculated by the following formula.

[0218] Resilience (%) = (Thickness of the test piece before testing - Thickness of the test piece after testing) ÷ (Original thickness of the test piece - Thickness of the spacer) × 100

[0219] The fixtures and measurement methods used above, except for the timing of fixture removal, are in accordance with ASTM-D395.

[0220] [Cross-linked rubber products]

[0221] The crosslinked rubber article of the present invention is an article obtained from the above-described crosslinking composition (hereinafter, "this crosslinking composition 1" and "this crosslinking composition 2" are simply referred to as "this crosslinking composition").

[0222] As a crosslinking method for the copolymer (A) in this crosslinking composition, a crosslinking method by heating the crosslinking composition is preferred.

[0223] Specific examples of crosslinking methods utilizing heat include hot-press crosslinking, steam crosslinking, and hot-air crosslinking. The appropriate method can be selected from these methods, taking into account the shape and intended use of the crosslinking composition.

[0224] The preferred heating conditions are 100~400℃ for 1 second to 24 hours.

[0225] Alternatively, the crosslinked rubber formed by heating the crosslinked composition (first crosslinking) can be further heated to undergo a second crosslinking. By undergoing a second crosslinking, the mechanical properties, compression set, and other properties of the crosslinked rubber can be stabilized or improved.

[0226] The preferred heating conditions for the second crosslinking are 80~350℃ for 30 minutes to 48 hours.

[0227] As a crosslinking method other than crosslinking the crosslinking composition by heating, a method of crosslinking the crosslinking composition by irradiating it with radiation can be cited. Specific examples of the irradiated radiation include electron beams and ultraviolet light.

[0228] The adhesion strength of the cross-linked rubber article is preferably 23 kgf or less, more preferably 20 kgf or less, and even more preferably 10 kgf or less. If it is 23 kgf or less, the movable components such as doors and covers of semiconductor devices are not easily fixed to the cross-linked rubber article, and the movable components are not easily rendered immobile.

[0229] It should be noted that the method for measuring adhesion can be illustrated by the method shown in the examples.

[0230] <Applications>

[0231] Cross-linked rubber products are suitable for materials such as O-rings, sheets, gaskets, oil seals, diaphragms, and V-rings. In addition, it is also suitable for applications such as heat-resistant and chemical-resistant sealing materials, heat-resistant and oil-resistant sealing materials, wire sheathing materials, sealing materials for semiconductor manufacturing equipment, sealing materials for liquid crystal display panel manufacturing equipment, sealing materials for light-emitting diode manufacturing equipment, corrosion-resistant rubber coatings, sealing materials for urea-based greases, rubber coatings, adhesive rubber, hoses, pipes, calendered sheets (rollers), sponges, rubber rollers, components for oil excavation, heat sinks, solution crosslinks, rubber sponges, bearing seals (urea-resistant greases, etc.), liners (chemical-resistant), automotive insulating sheets, insulating sheets for electronic devices, rubber belts for watches, endoscope seals (amine-resistant), corrugated hoses (processed from calendered sheets), water heater seals / valves, fender materials (marine and civil engineering, shipbuilding), fiber and non-woven fabrics (protective clothing, etc.), basic sealing materials, rubber gloves, stators for single-shaft eccentric screw pumps, components for urea SCR systems, vibration damping agents, shock absorbers, sealants, additives to other materials, and toys.

[0232] Example

[0233] The present invention will now be illustrated by examples. Examples 4, 5, and 9 are exemplary embodiments, and Examples 1-3, 6-8, and 10 are comparative examples. However, the present invention is not limited to these examples. It should be noted that the mixing amounts of each component in the tables described below represent mass references.

[0234] [Determination of the composition of fluorinated copolymers]

[0235] The content (molar percentage) of each unit in copolymers (A-1) to (A-4) described later is determined by... 19 The content of propylene units was calculated using 1 / 2 ppm nuclear magnetic resonance (NMR) analysis. 1 H and 13 Calculated by C-nuclear magnetic resonance (NMR) analysis.

[0236] The content (mol%) of each unit in the copolymer (B-1) described later was calculated by melt NMR analysis and fluorine content analysis. The content of the NAH unit was calculated by the following infrared absorption spectroscopy analysis.

[0237] (Infrared absorption spectroscopy analysis)

[0238] The copolymer (B-1), described later, was pressed into a film with a thickness of 200 μm. In the infrared absorption spectrum, the absorption peaks of the NAH-based units in copolymer (B-1) were all at 1778 cm⁻¹. -1 The absorbance of this absorption peak was measured using the molar absorptivity of NAH, which is 20810 mol / L. -1 ·l·cm -1Determine the proportion of NAH units in copolymer (B-1).

[0239] [Energy Storage Modulus]

[0240] As a measuring device, the apparatus used is PREMER RPA (manufactured by Alpha Technologies, mold shape: D0380).

[0241] Using the fluorinated copolymer composition used in each example, prepare a sheet-like test specimen (approximately 10 g in weight) with a thickness of 3 mm. Clamp the sheet-like test specimen between two polyester films (ALFA Technologies PART#F0311-S, 130 mm × 130 mm × 24 μm). Load the test specimen clamped by the polyester films onto a die. The temperature of the die is set to 100 °C.

[0242] Next, the sheet-like test sample was held at 100°C, a frequency of 30 cpm, and an amplitude angle of 0.2 degrees for 2 minutes. The amplitude angle was then set to 0.5 degrees, and the frequency was increased to 10 cpm, 20 cpm, and 50 cpm. The storage modulus at the frequency of 50 cpm, used for measuring the storage modulus, was taken as the storage modulus of the fluorinated copolymer composition. The results are shown in the "Storage Modulus (kPa)" column of Table 1.

[0243] [Restoration]

[0244] The resilience was determined using cross-linked rubber articles (O-rings described later (size: P-26)) as test pieces.

[0245] Specifically, in an oven, cross-linked rubber articles were compressed at 200°C for 70 hours at a compression rate of 25% using a clamp. The clamp holding the test piece was then removed from the oven, and the test piece was left at room temperature for 24 hours while still held in the clamp. The test piece was then removed from the clamp, and its thickness was measured after 30 minutes. The recovery rate was evaluated as recovery (%). The results are shown in the "Recovery (%)" column of Table 1.

[0246] Resilience (%) = (Thickness of the test piece before testing - Thickness of the test piece after testing) ÷ (Original thickness of the test piece - Thickness of the spacer) × 100

[0247] The fixtures and measurement methods used above, except for the timing of fixture removal, are in accordance with ASTM-D395.

[0248] [Fixity]

[0249] Wipe the surface of the O-rings with water and wipe the aluminum clamps with acetone.

[0250] Next, the O-ring was clamped between two A6061 aluminum plates with a spacer (2.625mm thick) and compressed at a compression rate of 25%, then placed at 200°C for 24 hours. A TABAI inert oven, model IHPS-222, was used as the drying oven.

[0251] Remove the sample from the oven and cool it under 25% compression. Then, release the pressure and place it in a constant temperature environment of 23°C and 50% humidity for 24 hours.

[0252] Then, the aluminum sheet was peeled off under the following apparatus and test conditions, using the maximum point load (kgf) as the fixation force. The results are shown in the "Fixation Force (kgf)" column of Table 1.

[0253] Test conditions:

[0254] Peeling speed 5mm / min

[0255] Device:

[0256] Strograph, manufactured by Toyo Seiki Co., Ltd.: STROGRAPH-R2

[0257] Load sensor: 981N RCT-100KR-AF

[0258] Range: ×2

[0259] [Preparation of copolymer (A-1)]

[0260] After degassing a 20L stainless steel pressure reactor equipped with an anchor-type agitator, 7.2L of ultrapure water, 880g of a 30% (w / w) solution of C2F5OCF2CF2OCF2COONH4 (as emulsifier), 7.3g of 8CNVE, and 15.9g of a 5% (w / w) aqueous solution of disodium hydrogen phosphate dodecahydrate were added to purge the gas phase with nitrogen. While stirring with the anchor-type agitator at 375 rpm, 137g of TFE and 635g of PMVE were added into the container, and the internal temperature was raised to 80°C. The reactor internal pressure was 0.90 MPa (gauge pressure). 28mL of a 3% (w / w) aqueous solution of ammonium persulfate (APS) was added to initiate polymerization. The molar ratio of the monomers added before polymerization (hereinafter referred to as "initial added monomers") was TFE:PMVE:8CNVE = 26.3:73.3:0.4.

[0261] After polymerization begins, monomers are added as polymerization proceeds. Hereinafter, monomers added after polymerization begins will be referred to as "post-added monomers".

[0262] When the pressure inside the reactor drops to 0.89 MPa, TFE is injected to raise the pressure to 0.90 MPa. This operation is repeated, with 3.7 g of 8CNVE, 74 g of PMVE, and 3.7 g of 8CNVE injected sequentially each time 119.3 g of TFE is injected.

[0263] When the polymerization rate decreases, add an appropriate amount of 3% (w / w) aqueous solution of APS. The total amount of 3% (w / w) aqueous solution of APS added after the start of polymerization is 35 mL.

[0264] At the end of the cycle when the total added mass of TFE reached 1073.7g, 119.3g of TFE was added. When the total added mass of the subsequently added TFE reached 1193g, the addition of the subsequent monomers was stopped, and the reactor temperature was cooled to 10°C to stop the polymerization reaction, yielding a latex containing a fluorinated copolymer. The polymerization time was 375 minutes. Furthermore, regarding the total added masses of each subsequent monomer—TFE 1193g, PMVE 666g, and 8CNVE 66.6g—the molar ratio is TFE:PMVE:8CNVE = 74.0:25.0:1.0.

[0265] Latex was added to a 5% (w / w) aqueous solution of potassium aluminum sulfate to cause the fluorinated copolymer to aggregate and separate. The fluorinated copolymer was filtered, washed with ultrapure water, and vacuum dried at 50°C to obtain a white fluorinated copolymer (hereinafter referred to as "copolymer (A-1)"). The content (molar ratio) of each unit in the obtained copolymer (A-1) was TFE unit: PMVE unit: 8CNVE unit = 70.9: 28.6: 0.5.

[0266] [Preparation of copolymer (A-2)]

[0267] Except for changing the amount of raw materials used, copolymer (A-2) was obtained by following the same steps as described above for the manufacture of copolymer (A-2). The content (molar ratio) of each unit in the obtained copolymer (A-2) was TFE unit: PMVE unit: 8CNVE unit = 64.4: 35.1: 0.5.

[0268] [Preparation of copolymer (A-3)]

[0269] After degassing, a 20L stainless steel pressure reactor equipped with an anchor-type agitator was added, followed by the introduction of 8.2L of ultrapure water, 733g of a 30% (w / w) solution of C2F5OCF2CF2OCF2COONH4, 10.0g of C3DVE, and a 5% (w / w) aqueous solution of disodium hydrogen phosphate dodecahydrate. The gas phase was then purged with nitrogen. While stirring at 375 rpm using the anchor-type agitator, 198g of TFE and 454g of PMVE were added into the reactor after the internal temperature reached 80°C. The reactor pressure was 0.90 MPa. 40mL of a 1% (w / w) aqueous solution of ammonium persulfate was added to initiate polymerization. The molar ratio of the monomers added before polymerization (hereinafter referred to as the initial monomers) was TFE:PMVE:C3DVE = 41.74:57.64:0.61.

[0270] When the reactor pressure drops to 0.89 MPa as polymerization proceeds, TFE is injected to raise the reactor pressure to 0.90 MPa. This process is repeated, with 62 g of PMVE injected along with 80 g of TFE. Additionally, when 60 g of TFE is injected, 7.0 g of 1,4-diiodoperfluorobutane is injected into the reactor along with 50 mL of ultrapure water via an ampoule.

[0271] When the total added TFE mass reached 1200g, the addition of monomers (hereinafter referred to as "post-added monomers") that had been added after the start of polymerization was stopped, and the reactor temperature was cooled to 10°C to stop the polymerization reaction, yielding a latex containing a fluorinated copolymer. The polymerization time was 360 minutes. Furthermore, the total added mass of the post-added monomers was 1200g TFE and 868g PMVE, which, when converted to a molar ratio, resulted in TFE:PMVE = 68:32.

[0272] Nitric acid (manufactured by Kanto Chemical Co., Ltd., premium grade) was dissolved in ultrapure water to prepare a 3% (w / w) aqueous solution of nitric acid. Latex was added to the nitric acid aqueous solution in a container made of TFE / perfluoro(alkyl vinyl ether) copolymer (PFA) to cause the fluorinated copolymer to aggregate. The amount of the aqueous nitric acid solution was 150 parts by weight relative to 100 parts by weight of the fluorinated copolymer in the latex. The aggregated fluorinated copolymer was recovered by filtration and added to ultrapure water in the PFA container for washing by stirring at 200 rpm for 30 minutes. The amount of ultrapure water was 100 parts by weight relative to 100 parts by weight of the fluorinated copolymer. The washing process was repeated 10 times.

[0273] The fluorinated copolymer was recovered by filtration and then dried under reduced pressure at 50°C and 10 kPa to obtain copolymer (A-3). The molar ratio of each unit in copolymer (A-3) was TFE unit: PMVE unit: C3DVE unit = 69.91: 29.96: 0.13, and the iodine content was 0.10% by mass.

[0274] [Preparation of copolymer (A-4)]

[0275] After degassing a 2100 mL stainless steel pressure reactor equipped with an anchor-type agitator, 804 g of ultrapure water, 80.1 g of a 30% (w / w) solution of C2F5OCF2CF2OCF2COONH4, 0.72 g of C3DVE, 1.8 g of a 5% (w / w) aqueous solution of disodium hydrogen phosphate dodecahydrate, and 0.87 g of 1,4-diiodoperfluorobutane were added to purge the gas phase with nitrogen. While stirring with the anchor-type agitator at 600 rpm, 13 g of TFE and 65 g of PMVE were added into the reactor after the internal temperature reached 80 °C. The reactor internal pressure was 0.90 MPa. 20 mL of a 1% (w / w) aqueous solution of ammonium persulfate was added to initiate polymerization. The molar ratio of the monomers added before polymerization (hereinafter referred to as the initial monomers) was TFE:PMVE:C3DVE = 25:75:0.19.

[0276] When the pressure inside the reactor decreases to 0.89 MPa [gauge] as polymerization proceeds, TFE is injected to raise the pressure inside the reactor to 0.90 MPa [gauge]. This operation is repeated, with 7 g of PMVE injected for every 8 g of TFE injected.

[0277] When the total added mass of TFE reached 80g, the addition of monomers (hereinafter referred to as "post-added monomers") that had been added after the start of polymerization was stopped, and the reactor temperature was cooled to 10°C to stop the polymerization reaction, yielding a latex containing a fluorinated copolymer. The polymerization time was 185 minutes. Furthermore, the total added mass of the post-added monomers was 80g of TFE and 63g of PMVE, which, when converted to a molar ratio, resulted in TFE:PMVE = 65:35.

[0278] Nitric acid (manufactured by Kanto Chemical Co., Ltd., premium grade) was dissolved in ultrapure water to prepare a 3% (by mass) aqueous solution of nitric acid. Latex was added to the nitric acid aqueous solution in a container made of TFE / perfluoro(alkyl vinyl ether) copolymer (PFA) to cause the fluorinated copolymer to aggregate. The amount of the nitric acid aqueous solution was 150 parts by mass relative to 100 parts by mass of the fluorinated copolymer in the latex.

[0279] The aggregated fluorinated copolymer was recovered by filtration and then added to ultrapure water in a PFA container for washing by stirring at 200 rpm for 30 minutes. The amount of ultrapure water was 100 parts by weight relative to 100 parts by weight of copolymer. The washing process was repeated 10 times.

[0280] The fluorinated copolymer was recovered by filtration and then dried under reduced pressure at 50°C and 10 kPa to obtain a white copolymer (A-4). The molar ratio of each unit in the fluorinated copolymer (A-4) was TFE unit: PMVE unit: C3DVE unit = 65.88: 33.94: 0.18, and the iodine atom content was 0.15% by mass.

[0281] [Preparation of copolymer (B-1)]

[0282] The product obtained by pulverizing the "fluorinated copolymer (X1-1)" in the Example column of International Publication No. 2016 / 017801 using a jet mill was used as copolymer (B-1). The molar ratio of each unit in copolymer (B-1) was NAH unit: TFE unit: PPVE unit = 0.1: 97.9: 2.0.

[0283] The copolymer (B-1) is a resin particle with a melting point of 310℃ and an average particle size (D50) of 2~3μm.

[0284] [Example 1~Example 10]

[0285] The components and mixing amounts (parts by mass) shown in Table 1 were prepared and mixed using two rollers at room temperature for 10 minutes to obtain a mixed fluorinated copolymer composition. Then, the fluorinated copolymer composition was mixed with a crosslinking agent using two rollers with the components and mixing amounts shown in Table 1 to obtain a crosslinked composition. For example, in Example 4, copolymer (A-2), copolymer (B-1), and TOCP were mixed to obtain a fluorinated copolymer composition, and then the fluorinated copolymer composition was mixed with BOAP (crosslinking agent) to obtain a crosslinked composition.

[0286] The obtained crosslinking composition was hot-pressed using a hydraulic press (model: SA-301 50T, manufactured by TESTER Industries, head diameter: 180 mm) under the conditions shown below to obtain O-rings (size: P-26) (single crosslinking). The single crosslinking of Examples 1-4 and 9 was performed by hot pressing at 180°C for 20 minutes. The single crosslinking of Examples 5-8 was performed by hot pressing at 150°C for 20 minutes. The single crosslinking of Example 10 was performed by hot pressing at 170°C for 10 minutes.

[0287] Then, under a nitrogen atmosphere, the O-rings were heated in an oven under the conditions shown below (double crosslinking). In Examples 1-4 and 9, the double crosslinking was performed by heating at 90°C for 2 hours, followed by a 2-hour increase to 200°C, and holding at 200°C for 4 hours. Then, the temperature was increased to 305°C for 2 hours, and then heated at 305°C for 13 hours. In Examples 5-8, the double crosslinking was performed by heating at 250°C for 4 hours. In Example 10, the double crosslinking was performed by heating at 200°C for 24 hours.

[0288] Then, the O-rings are cooled to room temperature to obtain the O-rings of Examples 1 to 10. The O-rings are equivalent to cross-linked rubber articles.

[0289] The aforementioned physical properties were determined using the obtained O-ring. The results are shown in Table 1.

[0290] The following is a summary of the components listed in Table 1, excluding the fluorinated copolymers (A-1) to (A-4) and (B-1).

[0291] The copolymer (A-5) has a fluorine content of 66% by mass, a Mooney viscosity (ML1+10 at 121°C) of 53 at its center, and a specific gravity of 1.83 g / cm³. 3 Ternary FKM (TFE / VdF / HFP copolymer)

[0292] TOCP: Manufactured by Beixing Chemical Industry Co., Ltd., Tri-n-octylphosphine (liquid at 20°C), Specific phosphorus compounds

[0293] C6-DV: Made by Tosoh Finechem Corporation, CH2=CH-(CF2)6-CH=CH2

[0294] TAIC: Trade name, manufactured by Mitsubishi Chemical Corporation, triallyl isocyanurate.

[0295] BOAP: 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, polyamine compound (crosslinking agent)

[0296] P-25B (PERHEXA 25B): Trade name, manufactured by Nippon Oils & Fats Co., Ltd., 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, organic peroxide (crosslinking agent).

[0297] [Table 1]

[0298]

[0299] As shown in the table, it is confirmed that the effects of the present invention can be obtained if this composition is used.

[0300] If the O-ring's fixing force is less than 23 kgf, it will be difficult to fix it to the aluminum plate used in the fixation test.

[0301] In Example 10, the O-ring did not detach from the aluminum plate used in the adhesion test. This is the same phenomenon as in Example 8.

[0302] It should be noted that the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2023-221216, filed on December 27, 2023, are incorporated herein as a disclosure of the specification of this invention.

Claims

1. A fluorinated copolymer composition comprising a fluorinated copolymer (A) and a fluorinated copolymer (B), The fluorinated copolymer (A) has tetrafluoroethylene-based units and perfluoro(alkyl vinyl ether)-based units. The fluorinated copolymer (B) is a fluorinated copolymer different from the fluorinated copolymer (A), having units based on monomers having at least one functional group selected from the group consisting of carboxyl groups and groups represented by formula (X), units based on tetrafluoroethylene, and units based on perfluorinated (alkyl vinyl ethers). The fluorinated copolymer composition has a storage modulus of less than 650 kPa at 100°C. Formula (X) *-CO-O-CO-* In equation (X), * represents the bonding position.

2. The fluorinated copolymer composition according to claim 1, wherein, The fluorinated copolymer (A) contains units having nitrile groups. The content of the nitrile-containing unit is more than 0.14 mol% and less than 0.7 mol% relative to all units of the fluorinated copolymer (A).

3. The fluorinated copolymer composition according to claim 1 or 2, wherein, The content of the monomer units in the fluorinated copolymer (B) that are based on at least one functional group selected from the group consisting of a carboxyl group and a group represented by formula (X) is 0.01 to 3 mol% relative to all units of the polymer (B); the content of the tetrafluoroethylene-based units is 90 to 99.89 mol% relative to all units of the polymer (B); and the content of the perfluoro(alkyl vinyl ether)-based units is 0.1 to 9.99 mol% relative to all units of the polymer (B).

4. The fluorinated copolymer composition according to claim 1 or 2, further comprising the compound represented by formula (9), H2C=CH-R 91 -R 93 -R 92 -CH=CH2 Equation (9) R 91 and R 92 Each can be independently represented as CH2 or CF2, R 93 It refers to a fluorocarbon group with 1 to 10 carbon atoms in a divalent state, or a group having an ether-like oxygen atom at the end of the fluorocarbon group or between carbon-carbon bonds.

5. The fluorinated copolymer composition according to claim 4, wherein, The content of the compound represented by formula (9) is 0.1 to 5 parts by mass relative to 100 parts by mass of the fluorinated copolymer (A).

6. The fluorinated copolymer composition according to claim 1 or 2, further comprising a phosphorus compound having a melting point below 60°C.

7. The fluorinated copolymer composition according to claim 6, wherein, The content of the phosphorus compound is 0.2 to 5 parts by mass relative to 100 parts by mass of the fluorinated copolymer (A).

8. The fluorinated copolymer composition according to claim 1 or 2, wherein, The content of the fluorinated copolymer (B) is 2 to 50 parts by mass relative to 100 parts by mass of the fluorinated copolymer (A).

9. A crosslinking composition comprising the fluorinated copolymer composition of claim 1, and further comprising a crosslinking agent.

10. The crosslinking composition according to claim 9, wherein, The crosslinking agent is a compound having two or more amino groups.

11. The crosslinking composition according to claim 9, wherein, The content of the crosslinking agent is 0.3 to 10 parts by weight relative to 100 parts by weight of the fluorinated copolymer (A).

12. A crosslinking composition comprising a fluorinated copolymer (A), a fluorinated copolymer (B), and a crosslinking agent. The fluorinated copolymer (A) has tetrafluoroethylene-based units and perfluoro(alkyl vinyl ether)-based units. The fluorinated copolymer (B) is a fluorinated copolymer different from the fluorinated copolymer (A), having units based on monomers having at least one functional group selected from the group consisting of carboxyl groups and groups represented by formula (X), units based on tetrafluoroethylene, and units based on perfluorinated (alkyl vinyl ethers). The crosslinked rubber article obtained from the crosslinking composition exhibits less than 80% recovery in a recovery force test after compression at 200°C for 70 hours at a compression ratio of 25%. Formula (X) *-CO-O-CO-* In equation (X), * represents the bonding position.

13. A crosslinked rubber article obtained from the crosslinking composition of claim 9 or 12.

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