WO2023149500A1

WO2023149500A1 - Laminate and precursor laminate

Info

Publication number: WO2023149500A1
Application number: PCT/JP2023/003380
Authority: WO
Inventors: 旭史邦本
Original assignee: Ａｇｃ株式会社
Priority date: 2022-02-07
Filing date: 2023-02-02
Publication date: 2023-08-10

Abstract

The present invention provides a laminate having excellent dimensional stability after having been used in a high-temperature environment, and a precursor laminate constituting an uncrosslinked product thererof.　The laminate according to the present invention has a first crosslinking layer and a second crosslinking layer. The first crosslinking layer includes a crosslinked product of a fluorine-containing copolymer A1, and optionally includes a crosslinked product of a non-fluoropolymer A2. The second crosslinking layer includes a crosslinked product of a fluorine-containing copolymer B1, and optionally includes a crosslinked product of a non-fluoropolymer B2. The combination of units based on monomers constituting the fluorine-containing copolymer A1 and the combination of units based on monomers constituting the fluorine-containing copolymer B1 differ from each other. The content MCA of the crosslinked product of the fluorine-containing copolymer A1 is greater than or equal to 85 mass% with respect to the total of the crosslinked product of the fluorine-containing copolymer A1 and the crosslinked product of the non-fluoropolymer A2. The content MCB of the crosslinked product of the fluorine-containing copolymer B1 is greater than or equal to 85 mass% with respect to the total of the crosslinked product of the fluorine-containing copolymer B1 and the crosslinked product of the non-fluoropolymer B2.

Description

Laminates and precursor laminates

The present invention relates to laminates and precursor laminates.

　Fluorine-containing copolymers are used in a wide variety of fields due to their excellent heat resistance, chemical resistance, oil resistance, weather resistance, and electrical insulation. A fluorine-containing copolymer may be laminated with various polymers for use. As a laminate using a fluorine-containing copolymer, Patent Document 1 discloses a laminate having a rubber layer (1) containing a fluororubber and an acrylic rubber and a rubber layer (2) containing a fluororubber. ing.

WO 98/036901

Laminates using fluorine-containing copolymers are required to have heat resistance because they are used not only in low-temperature environments but also in high-temperature environments. When the inventors of the present invention evaluated the laminate as described in Patent Document 1, they found that there was room for improvement in terms of dimensional stability after use in a high-temperature environment, which is considered to be one of heat resistance. . Specifically, when the laminate as described in Patent Document 1 is used in a high-temperature environment, the layers constituting the laminate may shrink.

The present invention has been made in view of the above problems, and aims to provide a laminate having excellent dimensional stability after use in a high-temperature environment, and a precursor laminate that is an uncrosslinked product thereof.

As a result of intensive studies on the above problems, the present inventors have found that a first crosslinked layer containing a crosslinked product of a fluorocopolymer A1 and optionally a crosslinked product of a non-fluoropolymer A2 and a crosslinked fluorocopolymer B1 and optionally a crosslinked product of the non-fluoropolymer B2, the content M _CA of the crosslinked product of the fluorocopolymer A1 and the crosslinked product of the fluorocopolymer B1 The present inventors have found that when the content M _CB of each substance is at least a specific value, the dimensional stability after use in a high-temperature environment is excellent, leading to the present invention.

That is, the inventors have found that the above problems can be solved by the following configuration.
[1] A laminate having a first crosslinked layer and a second crosslinked layer disposed on the first crosslinked layer,
wherein the first crosslinked layer contains a crosslinked product of a fluorine-containing copolymer A1 and optionally a crosslinked product of a non-fluoropolymer A2;
the second crosslinked layer comprises a crosslinked fluorocopolymer B1 and optionally a crosslinked non-fluoropolymer B2;
the combination of units based on the monomers constituting the fluorocopolymer A1 and the combination of units based on the monomers constituting the fluorocopolymer B1 are different from each other,
The content M _CA of the crosslinked product of the fluorocopolymer A1 with respect to the total of the crosslinked product of the fluorocopolymer A1 and the crosslinked product of the non-fluoropolymer A2 is 85% by mass or more,
The content _MCB of the crosslinked product of the fluorocopolymer B1 with respect to the total of the crosslinked product of the fluorocopolymer B1 and the crosslinked product of the non-fluoropolymer B2 is 85% by mass or more. A laminate, characterized in that:
[2] The laminate according to [1], wherein the absolute value of the difference between the _MCA and the _MCB is 15% by mass or less.
[3] The fluorine-containing copolymer A1 contains units based on vinylidene fluoride,
The laminate according to [1] or [2], wherein the fluorine-containing copolymer B1 contains units based on tetrafluoroethylene and units based on propylene.
[4] The laminate according to any one of [1] to [3], wherein at least one of the fluorine-containing copolymer A1 and the fluorine-containing copolymer B1 has at least one of an iodine atom and a bromine atom.
[5] The laminate according to any one of [1] to [4], wherein both the fluorine-containing copolymer A1 and the fluorine-containing copolymer B1 have a glass transition temperature of 15° C. or lower.
[6] The laminate according to any one of [1] to [5], wherein at least one of the first crosslinked layer and the second crosslinked layer further contains at least one of sintered diatomaceous earth and silica.
[7] The laminate according to any one of [1] to [6], wherein at least one of the first crosslinked layer and the second crosslinked layer further contains a sintered body of diatomaceous earth and silica.
[8] The first crosslinked layer does not contain the crosslinked product of the non-fluoropolymer A2,
The laminate according to any one of [1] to [7], wherein the second crosslinked layer does not contain a crosslinked product of the non-fluoropolymer B2.
[9] A precursor laminate having a first composition layer and a second composition layer disposed on the first composition layer,
wherein the first composition layer comprises a fluorine-containing copolymer A1, a cross-linking agent, and optionally a non-fluoropolymer A2;
the second composition layer comprises a fluorine-containing copolymer B1, a cross-linking agent, and optionally a non-fluoropolymer B2;
the combination of units based on the monomers constituting the fluorocopolymer A1 and the combination of units based on the monomers constituting the fluorocopolymer B1 are different from each other,
The content M _PA of the fluorocopolymer A1 with respect to the total of the fluorocopolymer A1 and the non-fluoropolymer A2 is 85% by mass or more,
A precursor laminate, wherein the content M _PB of the fluorine-containing copolymer B1 with respect to the total of the fluorine-containing copolymer B1 and the non-fluorine-containing polymer B2 is 85% by mass or more.
[10] The precursor laminate according to [9], wherein the absolute value of the difference between the _MPA and the _MPB is 15% by mass or less.
[11] The fluorine-containing copolymer A1 contains units based on vinylidene fluoride,
The precursor laminate according to [9] or [10], wherein the fluorine-containing copolymer B1 contains units based on tetrafluoroethylene and units based on propylene.
[12] The precursor laminate according to any one of [9] to [11], wherein at least one of the fluorine-containing copolymer A1 and the fluorine-containing copolymer B1 has at least one of an iodine atom and a bromine atom. body.
[13] The precursor laminate according to any one of [9] to [12], wherein both the fluorine-containing copolymer A1 and the fluorine-containing copolymer B1 have a glass transition temperature of 15°C or less.
[14] The precursor according to any one of [9] to [13], wherein at least one of the first composition layer and the second composition layer further contains at least one of sintered diatomaceous earth and silica. body laminate.
[15] The precursor according to any one of [9] to [14], wherein at least one of the first composition layer and the second composition layer further contains a sintered body of diatomaceous earth and silica. laminate.
[16] wherein the first composition layer does not contain the non-fluoropolymer A2,
The precursor laminate according to any one of [9] to [14], wherein the second composition layer does not contain the non-fluoropolymer B2.

According to the present invention, it is possible to provide a laminate that has excellent dimensional stability after use in a high-temperature environment, and a precursor laminate that is an uncrosslinked product thereof.

The terms used in the present invention have the following meanings.
A numerical range represented using "to" means a range including the numerical values described before and after "to" as lower and upper limits. In the numerical ranges described stepwise in this specification, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described stepwise. Moreover, in the numerical ranges described in this specification, the upper limit or lower limit described in a certain numerical range may be replaced with the values shown in the examples.
In the present specification, for each component, one type of substance corresponding to each component may be used alone, or two or more types may be used in combination. Here, when two or more substances are used in combination for each component, the content of the component refers to the total content of the substances used in combination unless otherwise specified.
In the present specification, a combination of two or more preferred aspects is a more preferred aspect.
"Unit" is a general term for an atomic group derived from one molecule of the above-mentioned monomer directly formed by polymerization of the monomer, and an atomic group obtained by chemically converting a part of the above-mentioned atomic group. be. A "unit based on a monomer" is hereinafter simply referred to as a "unit".
"Rubber" means rubber exhibiting properties defined by JIS K 6200:2008, and is distinguished from "resin".
"Glass transition temperature" is the midpoint glass transition temperature as measured by differential scanning calorimetry (DSC). "Glass transition temperature" is also referred to as "Tg."

[Laminate]
A laminate of the present invention (hereinafter also referred to as "this laminate") is a laminate having a first crosslinked layer and a second crosslinked layer disposed on the first crosslinked layer, The first crosslinked layer comprises a crosslinked fluorocopolymer A1 and optionally a crosslinked non-fluoropolymer A2, the second crosslinked layer comprises a crosslinked fluorocopolymer B1, It optionally contains cross-linked non-fluoropolymer B2.
Further, in the present laminate, the combination of units based on the monomers constituting the fluorocopolymer A1 and the combination of units based on the monomers constituting the fluorocopolymer B1 are different from each other. .
Further, in the present laminate, the content M _CA of the crosslinked product of the fluorocopolymer A1 with respect to the total of the crosslinked product of the fluorocopolymer A1 and the crosslinked product of the non-fluoropolymer A2 is 85 mass. % or more, and the content M _CB of the crosslinked product of the fluorocopolymer B1 is 85% by mass or more with respect to the total of the crosslinked product of the fluorocopolymer B1 and the crosslinked product of the non-fluoropolymer B2. is.

The laminate has excellent dimensional stability after being used in a high-temperature environment.
Since the crosslinked product of the fluorine-containing copolymer has excellent heat resistance, the thermal shrinkage of the first crosslinked layer and the second crosslinked layer is sufficiently reduced when both _MCA and _MCB are 85% by mass or more. , it is presumed that the dimensional change after the laminate was stored in a high-temperature environment became small.

[First crosslinked layer]
The first crosslinked layer contains a crosslinked product of the fluorine-containing copolymer A1 and optionally a crosslinked product of the non-fluoropolymer A2.

<Fluorine-containing copolymer A1>
The fluorine-containing copolymer A1 is a copolymer having fluorine atoms and containing units based on two or more kinds of monomers, and exhibits rubber properties by cross-linking. That is, the crosslinked product of the fluorine-containing copolymer A1 exhibits rubber properties.

The fluorine-containing copolymer A1 preferably has a vinylidene fluoride (hereinafter also referred to as "VdF") unit from the viewpoint of excellent fuel permeation resistance and excellent rubber properties in a low-temperature environment. , It is more preferable to have hexafluoropropylene (hereinafter also referred to as “HFP”) units, and to have VdF units, tetrafluoroethylene (hereinafter also referred to as “TFE”) units, and HFP units. More preferred.

The fluorine-containing copolymer A1 has a unit (hereinafter also referred to as "another monomer 1 unit") based on a monomer other than the above (hereinafter also referred to as "another monomer 1"). may be Specific examples of the other monomer 1 include monomers having two or more polymerizable unsaturated bonds (hereinafter also referred to as "monomer a"), chlorotrifluoroethylene (hereinafter also referred to as "CTFE" ), 2,3,3,3-tetrafluoropropene (HFO-1234yf), (Z)-1-chloro-2,3,3,3,-tetrafluoropropene (HCFO-1224yd(Z)), per Examples include fluoro(alkyl vinyl ether) (hereinafter also referred to as "PAVE"), monomers represented by the following formula (5), ethylene, and propylene. In addition, monomers other than those described above and having a halogen atom (hereinafter also referred to as "monomers having other halogen atoms") are also included.

Specific examples of the polymerizable unsaturated bond include a carbon atom-carbon double bond (C=C) and a carbon atom-carbon triple bond (C≡C).
The number of polymerizable unsaturated bonds in the monomer a is preferably 2 to 6, more preferably 2 or 3, and particularly preferably 2, from the viewpoint of better polymerization reactivity.
Preferably, the monomer a further has a fluorine atom.

Monomer a is preferably a monomer represented by formula (1).
(CR ¹¹ R ¹² =CR ¹³ ) _a1 R ¹⁴ (1)
In formula (1), R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, a1 represents an integer of 2 to 6, and R ¹⁴ represents a1 It represents a perfluorohydrocarbon group having a valence of 1 to 10 carbon atoms, or a group having an etheric oxygen atom at the terminal or between the carbon-carbon bonds of the perfluorohydrocarbon group. A plurality of R ¹¹ s, a plurality of R ¹² and a plurality of R ¹³ may be the same or different, and are particularly preferably the same.
a1 is preferably 2 or 3, and particularly preferably 2.

R ¹¹ , R ¹² and R ¹³ are preferably each independently a fluorine atom or a hydrogen atom, and all of R ¹¹ , R ¹² and R ¹³ are fluorine atoms from the viewpoint of better polymerization reactivity of the monomer a. or a hydrogen atom, and from the viewpoint of the heat resistance and chemical resistance of the cured product, it is particularly preferred that all of R ¹¹ , R ¹² and R ¹³ are fluorine atoms.
R ¹⁴ may be linear, branched or cyclic, preferably linear or branched, and particularly preferably linear. The number of carbon atoms in R ¹⁴ is preferably 2-10, more preferably 3-8, still more preferably 3-6, and particularly preferably 3-5.
R ¹⁴ may or may not have an etheric oxygen atom, but preferably has an etheric oxygen atom from the viewpoint of better cross-linking reactivity and rubber physical properties.
The number of etheric oxygen atoms in R ¹⁴ is preferably 1-6, more preferably 1-3, and particularly preferably 1 or 2. The etheric oxygen atom in R ¹⁴ is preferably present at the terminal of R ¹⁴ .

Among the monomers represented by the formula (1), specific examples of suitable monomers include the monomers represented by the formula (2) and the monomers represented by the formula (3). be done.

( _CF2 =CF) _2R21 ⁽ 2)
In formula (2), R ²¹ represents a divalent perfluoroalkylene group having 2 to 10 carbon atoms, or a group having an etheric oxygen atom at the end of the perfluoroalkylene group or between carbon-carbon bonds.

Specific examples of the monomer represented by formula (2) include _CF2 =CFO( _CF2 ) _2OCF = _CF2 , _CF2 =CFO( _CF2 ) _3OCF = _CF2 , _CF2 =CFO( _CF2 ) ₄ OCF= _CF2 , _CF2 =CFO( _CF2 ) ₆ OCF=CF2 _, _CF2 = _CFO ( _CF2 ) ₈ OCF=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 _.
Specific examples of more preferred monomers among the monomers represented by formula (2) include CF ₂ =CFO(CF ₂ ) ₃ OCF=CF ₂ (hereinafter also referred to as “C3DVE”), CF ₂ =CFO(CF ₂ ) ₄ OCF=CF ₂ (hereinafter also referred to as “C4DVE” or “PBDVE”).

( _CH2 =CH) _2R31 ⁽ 3)
In formula (3), R ³¹ represents a divalent perfluoroalkylene group having 2 to 10 carbon atoms, or a group having an etheric oxygen atom at the end of the perfluoroalkylene group or between carbon-carbon bonds.

Specific examples of the monomer represented by formula (3) include _CH2 =CH( _CF2 ) _2CH = _CH2 , _CH2 =CH( _CF2 ) _4CH = _CH2 , _CH2 =CH( _CF2 ) _6CH = _CH2 .
Among the monomers represented by the formula (3), a specific example of a more preferable monomer is CH ₂ =CH(CF ₂ ) ₆ CH=CH ₂ (hereinafter also referred to as “C6DV”). mentioned.

When the monomer a is copolymerized, the polymerizable double bond at the terminal of the monomer a reacts during the polymerization to obtain a fluorine-containing copolymer A1 having a branched chain.

PAVE units are units based on perfluoro(alkyl vinyl ether).
PAVE is preferably a monomer represented by the formula (4) from the viewpoint of excellent polymerization reactivity and rubber physical properties.
CF ₂ =CF-OR ^f4 (4)
In formula (4), R ^f4 represents a perfluoroalkyl group having 1 to 10 carbon atoms. The number of carbon atoms in R ^f4 is preferably 1 to 8, more preferably 1 to 6, even more preferably 1 to 5, and particularly preferably 1 to 3, from the viewpoint of better polymerization reactivity.
A perfluoroalkyl group may be linear or branched.

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”), perfluoro(propyl vinyl ether) (hereinafter also referred to as “PEVE”). Also referred to as “PPVE”), and among these, PMVE and PPVE are preferred.

Equation (5) is as follows.
CF ₂ = CF-OR ^f5 (5)
In formula (5), R ^f5 represents a C 1-8 perfluoroalkyl group containing 1-5 etheric oxygen atoms. The number of carbon atoms in R ^f5 is preferably 1-6, particularly preferably 1-5.

Specific examples of the monomer represented by formula (5) include perfluoro(3,6-dioxa-1-heptene), perfluoro(3,6-dioxa-1-octene), perfluoro(5- methyl-3,6-dioxa-1-nonene).

A monomer having at least one of an iodine atom and a bromine atom is preferable as the monomer having another halogen atom. Specific examples of such monomers include CF ₂ =CFBr, CH ₂ =CHCF ₂ CF ₂ Br, CF ₂ =CF-O-CF ₂ CF ₂ -I, CF ₂ =CF-O-CF ₂ CF ₂ -Br, _CF2 = _CF -O _- _CF2CF2CH2 _- I, _CF2 =CF-O- _CF2CF2CH2 -Br, _CF2 =CF-O _- _CF2CF2 ₍ _CF3 )-O-CF ₂ CF ₂ CH ₂ -I, CF ₂ =CF-O-CF ₂ CF ₂ (CF ₃ )-O-CF ₂ CF ₂ CH ₂ -Br.

When the fluorocopolymer A1 contains VdF units, the content of the VdF units is preferably 45 to 70 mol %, more preferably 50 to 60 mol %, based on the total units of the fluorocopolymer A1.
When the fluorine-containing copolymer A1 contains TFE units, the content of the TFE units is preferably 10 to 25 mol %, more preferably 20 to 22 mol %, based on the total units of the fluorine-containing copolymer A1.
When the fluorocopolymer A1 contains HFP units, the content of the HFP units is preferably 15 to 30 mol%, more preferably 20 to 28 mol%, based on the total units of the fluorocopolymer A1.
When the fluorocopolymer A1 contains 1 unit of another monomer, the content of 1 unit of the other monomer is 0.1 to 5 mol% with respect to the total units of the fluorocopolymer A1. is preferred, and 0.1 to 3 mol % is more preferred.

Preferred combinations of units contained in the fluorine-containing copolymer A1 are shown below.
Combination 1-1: Combination of VdF unit, TFE unit and HFP unit Combination 1-2: Combination of VdF unit and HFP unit

The copolymer compositions in Combinations 1-1 and 1-2 preferably have the following molar ratios. With the following molar ratios, the cross-linking reactivity of the copolymer is excellent, and the fuel permeation resistance of the cross-linked product, rubber properties in low-temperature environments, and the like are further excellent.
Combination 1-1: VdF unit/TFE unit/HFP unit = 45 to 70/10 to 25/15 to 30 (molar ratio)
Combination 1-2: VdF unit / HFP unit = 70 ~ 80 / 20 ~ 30 (molar ratio)

The fluorine-containing copolymer A1 preferably has at least one of an iodine atom and a bromine atom. An iodine atom and a bromine atom react with an organic peroxide, which will be described later, and become a cross-linking site when cross-linking the fluorine-containing copolymer A1. Since iodine atoms and bromine atoms have good reactivity, fluorine-containing copolymers containing at least one of iodine atoms and bromine atoms have a high cross-linking speed. When the fluorine-containing copolymer A1 having iodine atoms and bromine atoms is crosslinked with an organic peroxide, the resulting crosslinked product has excellent chemical resistance. Also, the adhesiveness between the first crosslinked layer and the second crosslinked layer can be improved.
The iodine atom or bromine atom that the fluorine-containing copolymer A1 may have includes an iodine atom or a bromine atom derived from a chain transfer agent having at least one of an iodine atom and a bromine atom described later, and an iodine atom and a bromine atom described above. An iodine atom or a bromine atom in units based on monomers having at least one. Among them, an iodine atom or a bromine atom derived from a chain transfer agent having at least one of an iodine atom and a bromine atom, which will be described later, is preferable.
When a chain transfer agent is used, at least one of an iodine atom and a bromine atom can be introduced at the end of the fluorine-containing copolymer (polymer chain).
When a monomer having at least one of an iodine atom and a bromine atom is used, at least one of the iodine atom and the bromine atom can be introduced into the side chain of the fluorine-containing copolymer.

Of the iodine atoms and the bromine atoms, the fluorine-containing copolymer A1 preferably has an iodine atom from the viewpoint of the cross-linking reactivity of the fluorine-containing copolymer A1.

When the fluorine-containing copolymer A1 has at least one of an iodine atom and a bromine atom, the total content of the iodine atom and the bromine atom is 0.01 to 5.0% relative to the total mass of the fluorine-containing copolymer A1. 0% by mass is preferable, 0.05 to 2.0% by mass is more preferable, and 0.1 to 1.0% by mass is particularly preferable. When the total content is within the above range, the cross-linking reactivity of the fluorine-containing copolymer A1 is improved, and the mechanical properties of the cross-linked product are excellent.
In addition, the total content of iodine atoms and bromine atoms means the content of one atom when only one atom is included, and the total content of each atom when both atoms are included. means.

A crosslinked product of the fluorine-containing copolymer A1 can be obtained, for example, by heating the above-mentioned fluorine-containing copolymer A1 in the presence of a crosslinking agent or the like described later.

The content M _CA of the crosslinked product of the fluorocopolymer A1 with respect to the total of the crosslinked product of the fluorocopolymer A1 and the crosslinked product of the non-fluoropolymer A2 described later is 85% by mass or more, and the present lamination It is preferably 90% by mass or more, more preferably 95% by mass or more, from the viewpoint of better dimensional stability after the body is used in a high-temperature environment.
Here, the sum of the cross-linked product of the fluorocopolymer A1 and the cross-linked product of the non-fluoropolymer A2 means that when the first crosslinked layer does not contain the cross-linked product of the non-fluoropolymer A2, It means the content of the crosslinked product of the polymer A1.
It is particularly preferred that the _MCA is 100% by weight. That is, it is particularly preferable that the first crosslinked layer does not contain a crosslinked product of the non-fluoropolymer A2. Thereby, the dimensional stability after using the present laminate in a high-temperature environment is more excellent.

The methods for measuring the content of the crosslinked product of the fluorocopolymer A1 and the content of the non-fluoropolymer A2 in the first crosslinked layer are as described in Examples below.

The content of the crosslinked product of the fluorine-containing copolymer A1 is 60 to 90 mass with respect to the total mass of the first crosslinked layer, since the dimensional stability of the laminate after use in a high temperature environment is superior. %, more preferably 64 to 90% by mass, even more preferably 68 to 83% by mass.

(Physical properties of fluorine-containing copolymer A1)
The Tg of the fluorine-containing copolymer A1 is preferably 15° C. or less, more preferably −30 to 15° C., more preferably −20 to 15° C., in order to sufficiently express the rubber properties of the cross-linked product of the fluorine-containing copolymer A1. -5°C is more preferred.

(Method for producing fluorine-containing copolymer A1)
An example of the method for producing the fluorine-containing copolymer A1 includes a method of polymerizing the above monomers in the presence of a chain transfer agent and a radical polymerization initiator.

Examples of chain transfer agents include chain transfer agents containing at least one of iodine and bromine atoms, chain or cyclic alkanes such as methane, ethane, propane, butane, pentane, hexane and cyclohexane, and alcohols such as methanol, ethanol and propanol. and tert-dodecylmercaptan, n-dodecylmercaptan, n-octadecylmercaptan and other mercaptans. Among them, a chain transfer agent containing at least one of an iodine atom and a bromine atom is preferable from the viewpoint of the cross-linking reactivity of the fluorine-containing copolymer A1.
A chain transfer agent may be used individually by 1 type, or may use 2 or more types together.

Specific examples of chain transfer agents having at least one of an iodine atom and a bromine atom include I—R ^f6 —I (wherein R ^f6 is a perfluoroalkylene group having 1 to 8 carbon atoms or a represents a perfluorooxyalkylene group of 8), a compound represented by IR ^f7 -Br (wherein R ^f7 is a perfluoroalkylene group having 1 to 8 carbon atoms or a perfluoroalkylene group having 2 to 8 carbon atoms) represents a perfluorooxyalkylene group), a compound represented by IR ¹ -I (wherein R ¹ is an alkylene group having 1 to 8 carbon atoms or an oxyalkylene group having 2 to 8 carbon atoms, is represented.) can be mentioned.
Specific examples of IR ^f6 -I include diiododifluoromethane, 1,2-diiodoperfluoroethane, 1,3-diiodoperfluoropropane, 1,4-diiodoperfluorobutane, 1,5 -diiodoperfluoropentane, 1,6-diiodoperfluorohexane, 1,7-diiodoperfluoroheptane, 1,8-diiodoperfluorooctane. Among them, 1,4-diiodoperfluorobutane and 1,6-diiodoperfluorohexane are preferable, and 1,4-diiodoperfluorobutane is particularly preferable.
Specific examples of IR ^f7 -Br include 1-iodo-4-bromoperfluorobutane, 1-iodo-6-bromoperfluorohexane, and 1-iodo-8-bromoperfluorooctane. Among them, 1-iodo-4-bromoperfluorobutane and 1-iodo-6-bromoperfluorohexane are preferred, and 1-iodo-4-bromoperfluorobutane is particularly preferred.
Specific examples of IR ¹ -I include 1,2-diiodoethane, 1,3-diiodopropane, 1,4-diiodobutane, 1,5-diiodopentane, 1,6-diiodohexane, 1, 8-diiodooctane is mentioned.
By polymerizing the above monomers in the presence of a chain transfer agent having at least one of these iodine and bromine atoms, iodine and/or bromine atoms can be introduced into the fluorine-containing copolymer.

When using a chain transfer agent having at least one of an iodine atom and a bromine atom, the charge amount is 0.1 part per 100 parts by mass of the total amount of monomers used in the polymerization of the fluorine-containing copolymer A1. 20 parts by weight is preferable, 0.5 to 17 parts by weight is more preferable, and 2 to 15 parts by weight is particularly preferable. If it is 0.1 parts by mass or more, the polymerization time can be shortened. Further, if it is 20 parts by mass or less, the rubber physical properties of the crosslinked product of the fluorine-containing copolymer A1 will be good.

The polymerization temperature is appropriately selected depending on the composition of the monomers, the decomposition temperature of the radical polymerization initiator, and the like. The polymerization temperature is preferably 0 to 60°C, more preferably 10 to 50°C, and particularly preferably 20 to 40°C.

For details of the components other than the above used in the production of the fluorine-containing copolymer A1 and the production method, see, for example, the methods described in Examples of Japanese Patent No. 4089923, Japanese Patent No. 3860114, and Japanese Patent No. 5744902. can.

<Non-fluoropolymer A2>
The non-fluoropolymer A2 is a polymer containing no fluorine atoms, and preferably exhibits rubber properties by cross-linking. That is, the crosslinked product of the non-fluoropolymer A2 preferably exhibits rubber properties.
Specific examples of the non-fluoropolymer A2 include (meth)acrylic acid ester polymers, ethylene-(meth)acrylic acid ester copolymers, silicone polymers, ethylene-propylene-diene copolymers, ethylene-propylene copolymers, Polymer, ethylene-vinyl acetate copolymer, chloroprene polymer, isobutylene-isoprene copolymer, isoprene polymer, butadiene polymer, chlorinated polyethylene, chlorosulfonated polyethylene, acrylonitrile-butadiene rubber, hydrogenated acrylonitrile-butadiene rubber is mentioned. Among them, ethylene-(meth)acrylic acid ester copolymers and ethylene-propylene-diene copolymers are preferred from the viewpoints of heat resistance, availability and economy.

The crosslinked product of non-fluoropolymer A2 can be obtained, for example, by heating non-fluoropolymer A2 described above in the presence of a crosslinking agent or the like described later.
Here, since the crosslinked product of the non-fluoropolymer A2 is an optional component, the first crosslinked layer may or may not contain the crosslinked product of the non-fluoropolymer A2. A crosslinked product of the non-fluoropolymer A2 may be added to the first crosslinked layer when it is desired to facilitate processing or to improve low temperature resistance. The laminate having the first crosslinked layer containing the crosslinked product of the non-fluoropolymer A2 is preferably used in an environment of less than 150°C. Moreover, the laminate having the first crosslinked layer containing the crosslinked product of the non-fluoropolymer A2 is preferably used so that the first crosslinked layer does not come into contact with the chemical solution.
The content of the crosslinked product of the non-fluoropolymer A2 is, relative to the total mass of the first crosslinked layer, from the viewpoint that the dimensional stability after the laminate is used in a high-temperature environment is more excellent and that warping can be suppressed. .

(Physical properties of non-fluoropolymer A2)
The Tg of the non-fluoropolymer A2 is preferably 15°C or less, more preferably -50 to 15°C, more preferably -30 to 10°C, from the viewpoint that the properties of the crosslinked product of the non-fluoropolymer A2 as a rubber are sufficiently expressed. is more preferred.

<Other ingredients>
The first crosslinked layer may contain components other than the crosslinked product of the fluorine-containing copolymer A1 and the crosslinked product of the non-fluoropolymer A2. Specific examples of such components include an uncrosslinked fluorocopolymer A1 (that is, the above-mentioned fluorocopolymer A1), an uncrosslinked non-fluoropolymer A2 (that is, the above-mentioned non-fluorinated polymer Coalescence A2), unreacted cross-linking agent, sintered diatomaceous earth, and silica.
Specific examples of components other than the above include unreacted cross-linking aids (e.g. triallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanurate), unreacted acid acceptors (e.g. fatty acid esters , fatty acid metal salts, divalent metal oxides (magnesium oxide, calcium oxide, zinc oxide, lead oxide, etc.), fillers (e.g., carbon black, barium sulfate, calcium metasilicate, calcium carbonate, titanium oxide, silicon dioxide , clay, talc), scorch retarders (e.g., o-phenylphenol, phenolic hydroxyl group-containing compounds such as bisphenol A, quinones such as hydroquinone, 2,4-di(3-isopropylphenyl)-4-methyl- α-methylstyrene dimers such as 1-pentene), crown ethers (e.g., 18-crown-6), plasticizers (e.g., adipate ether ester compounds), processing aids (e.g., oleic acid glyceride). .

When the first crosslinked layer contains other components, the content of the other components is preferably 20 to 32% by mass, more preferably 20 to 31% by mass, more preferably 20 to 31% by mass, based on the total mass of the first crosslinked layer. 30 mass % is more preferable.

(crosslinking agent)
Specific examples of the cross-linking agent include organic peroxides and amine-based cross-linking agents. Organic peroxides are preferred because the resulting cross-linked product has excellent chemical resistance.
Specific examples of organic peroxides include dialkyl peroxides, α,α'-bis(tert-butylperoxy)-p-diisopropylbenzene, α,α'-bis(tert-butylperoxy)-m- Diisopropylbenzene, benzoylperoxide, tert-butylperoxybenzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butylcumylperoxide, dicumylperoxide, bis-2,4-dichloro Benzoyl peroxide can be mentioned. Specific examples of dialkyl peroxides include 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroxyperoxide, 2,5 -dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne, tert-butylperoxymaleate, tert- Butyl peroxyisopropyl carbonate may be mentioned.
Specific examples of amine-based cross-linking agents include aliphatic polyamines such as ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine and hexamethylenetetramine, p-phenylenediamine, cumenediamine, N,N'-dicinnamylidene-1,6 - Aromatic polyamines such as hexanediamine, and amine carbamates such as ethylenediamine carbamate and hexamethylenediamine carbamate.

(Sintered body of diatomaceous earth)
The first crosslinked layer preferably contains a sintered body of diatomaceous earth in order to further improve the adhesion between the first crosslinked layer and the second crosslinked layer.

A sintered body of diatomaceous earth is obtained by firing diatomaceous earth. Diatomaceous earth is a soft rock or soil consisting mainly of diatom shells, containing silica as a main component, and further containing alumina, iron oxide, and the like.
The sintered body of diatomaceous earth is preferably Celite (registered trademark), which is a sintered body obtained by firing diatomaceous earth in the presence of a carbonate such as sodium carbonate.
Specific examples of sintered diatomaceous earth include Celite 350, Celite 505, Celite 512, Celite 577, and Standard Super-Cel (all manufactured by Celite Corporation).

When the first crosslinked layer contains a sintered body of diatomaceous earth, the content of the sintered body of diatomaceous earth is less than that of the fluorine-containing copolymer A1 because the adhesion between the first crosslinked layer and the second crosslinked layer is more excellent. It is preferably 1 to 10 parts by mass, more preferably 2 to 10 parts by mass, and even more preferably 5 to 10 parts by mass with respect to 100 parts by mass of the crosslinked product.
When the first crosslinked layer contains a sintered body of diatomaceous earth, the content of the sintered body of diatomaceous earth is preferably 1 to 10% by mass, more preferably 2 to 9% by mass, based on the total mass of the first crosslinked layer. Preferably, 3 to 8% by mass is more preferable.

(silica)
The first crosslinked layer preferably contains silica from the viewpoint of further improving the adhesion between the first crosslinked layer and the second crosslinked layer.
As silica, either hydrophobic silica or hydrophilic silica may be used. Hydrophilic silica is preferable because it can suppress deterioration of rubber physical properties.
Here, hydrophobic silica means silica that has been hydrophobized using hexamethyldisilazane, silicone oil, or the like.
Hydrophilic silica is silica that has not been subjected to the above hydrophobizing treatment, and specifically means silica having a hydrophilic group such as a silanol group on its surface.

The specific surface area of silica (especially hydrophilic silica) measured by the BET method is preferably 20 m ² /g or more, more preferably 30 to 1000 m ² /g, in order to further improve the adhesion between the first crosslinked layer and the second crosslinked layer. It is more preferably 70 to 500 m ² /g, particularly preferably 100 to 450 m 2 /g, further preferably 150 to 400 ^{m 2} ^/ g or less, and more preferably 175 to 350 m ² /g.

The apparent specific gravity of silica (particularly hydrophilic silica) is preferably 20 to 300 g/L, more preferably 30 to 250 g/L, more preferably 40, in order to further improve the adhesion between the first crosslinked layer and the second crosslinked layer. ~200 g/L is more preferred. When the apparent specific gravity is within the above range, the decrease in elongation of the crosslinked product of the fluorine-containing copolymer is suppressed, and good hardness is obtained.

The average primary particle size of silica is preferably 5 to 50 nm, more preferably 6 to 45 nm, and even more preferably 7 to 40 nm, in order to further improve the adhesion between the first crosslinked layer and the second crosslinked layer. When the average primary particle size of silica is within the above range, the uniform dispersibility of silica in the second crosslinked layer is excellent.
Silica is commercially available, and examples thereof include hydrophilic silicas such as AEROSIL 50, AEROSIL 200, and AEROSIL 300 (all of which are manufactured by Nippon Aerosil Co., Ltd.).
Silica may be used individually by 1 type, or may use 2 or more types together.

When the first crosslinked layer contains silica, the content of silica is 100 parts by mass of the crosslinked product of the fluorine-containing copolymer A1, since the adhesion between the first crosslinked layer and the second crosslinked layer can be further improved. On the other hand, 1 to 10 parts by mass is preferable, 2 to 10 parts by mass is more preferable, and 5 to 10 parts by mass is even more preferable.
When the first crosslinked layer contains silica, the content of silica is 1 to 10 with respect to the total mass of the first crosslinked layer, since the adhesion between the first crosslinked layer and the second crosslinked layer can be further improved. % by mass is preferable, 2 to 9% by mass is more preferable, and 3 to 8% by mass is even more preferable.

The first crosslinked layer may contain at least one of a sintered diatomaceous earth and silica, and more preferably contains both a sintered diatomaceous earth and silica. By including both the sintered body of diatomaceous earth and silica, the adhesion between the first crosslinked layer and the second crosslinked layer is particularly excellent. Although the details of this reason have not been clarified, hydrogen bonds and other intermolecular interactions between hydroxyl groups contained in the sintered diatomaceous earth and silica and hydrogen atoms in the fluorine-containing copolymer and non-fluorine polymer presumed to be involved.
When the first crosslinked layer contains both the sintered diatomaceous earth and silica, the ratio of the sintered diatomaceous earth and the silica content (sintered diatomaceous earth/silica) is the first crosslinked layer and the second crosslinked layer 1 to 10/1 to 10 is preferable, 2 to 10/2 to 10 is more preferable, and 5 to 10/5 to 10 is even more preferable, from the viewpoint that the adhesiveness to is more excellent.

[Second crosslinked layer]
The second crosslinked layer is arranged on the first crosslinked layer, and is preferably arranged so as to be in contact with the first crosslinked layer.
The second crosslinked layer contains a crosslinked product of the fluorine-containing copolymer B1 and optionally a crosslinked product of the non-fluoropolymer B2.

<Fluorine-containing copolymer B1>
The fluorine-containing copolymer B1 is a copolymer having fluorine atoms and containing units based on two or more kinds of monomers, and exhibits rubber properties by cross-linking. That is, the crosslinked product of the fluorine-containing copolymer B1 exhibits rubber properties.
The combination of units based on the monomers constituting the fluorocopolymer B1 is different from the combination of units based on the monomers constituting the fluorocopolymer A1.

The fluorine-containing copolymer B1 preferably has a TFE unit and a propylene unit from the viewpoint of excellent resistance to basic compounds described later.

The fluorine-containing copolymer B1 may have units based on monomers other than the above (hereinafter also referred to as "other monomers 2"). Specific examples of the other monomer 2 include monomer a, VdF, HFP, CTFE, PAVE, the monomer represented by the above formula (5), and ethylene. In addition, monomers other than those described above and having other halogen atoms are also included. Specific examples of these other monomers 2 are the same as the monomers described in the section of the first crosslinked layer, and preferred embodiments are also the same.

Although the fluorine-containing copolymer B1 may have VdF units, it is preferable that the second crosslinked layer has substantially no VdF units from the viewpoint of excellent chemical resistance (especially amine resistance). .
Here, "substantially free of VdF units" means that the content of VdF units is 0.1 mol% or less with respect to the total units of the fluorine-containing copolymer B1, and 0 mol % is preferred.

When the fluorine-containing copolymer B1 contains TFE units, the content of the TFE units is preferably 30 to 70 mol%, more preferably 40 to 60 mol%, based on the total units of the fluorocopolymer B1.
When the fluorocopolymer B1 contains propylene units, the content of the propylene units is preferably 30 to 70 mol%, more preferably 40 to 60 mol%, based on the total units of the fluorocopolymer B1.
When the fluorocopolymer B1 contains 2 other monomer units, the content of the 2 other monomer units is 0.01 to 10 mol% with respect to the total units of the fluorocopolymer B1. is preferred, and 0.05 to 5 mol % is more preferred.

Preferred combinations of units contained in the fluorine-containing copolymer B1 are shown below.
Combination 2-1: Combination of TFE units and propylene units

The copolymer composition in combination 2-1 preferably has the following molar ratio. With the following molar ratios, the cross-linking reactivity of the copolymer is further excellent, and the mechanical properties, heat resistance, chemical resistance, oil resistance, weather resistance, etc. of the cured product are excellent.
Combination 2-1: TFE unit/propylene unit = 40 to 60/40 to 60 (molar ratio)

The fluorine-containing copolymer B1 may have at least one of an iodine atom and a bromine atom. The iodine atom and the bromine atom serve as cross-linking sites when cross-linking the fluorine-containing copolymer B1.
Specific examples of the iodine atom or bromine atom that the fluorine-containing copolymer B1 may have are the same as the iodine atom and bromine atom described in the section of the first crosslinked layer, and the preferred embodiments are also the same.

When the fluorine-containing copolymer B1 has at least one of an iodine atom and a bromine atom, the total content of the iodine atom and the bromine atom is 0.01 to 5.0% relative to the total mass of the fluorine-containing copolymer B1. 0% by mass is preferable, 0.05 to 2.0% by mass is more preferable, and 0.1 to 1.0% by mass is particularly preferable. When the total content is within the above range, the cross-linking reactivity of the fluorine-containing copolymer B1 is improved, and the mechanical properties of the cross-linked product are excellent.
In addition, the total content of iodine atoms and bromine atoms means the content of one atom when only one atom is included, and the total content of each atom when both atoms are included. means.

At least one of the fluorine-containing copolymer A1 and the fluorine-containing copolymer B1 preferably has at least one of an iodine atom and a bromine atom, from the viewpoint of better adhesion between the first crosslinked layer and the second crosslinked layer, More preferably, both the fluorine-containing copolymer A1 and the fluorine-containing copolymer B1 have at least one of an iodine atom and a bromine atom.

A crosslinked product of the fluorine-containing copolymer B1 can be obtained, for example, by heating the above-mentioned fluorine-containing copolymer B1 in the presence of a crosslinking agent or the like described later.

The content M _CB of the crosslinked product of the fluorocopolymer B1 with respect to the total of the crosslinked product of the fluorocopolymer B1 and the crosslinked product of the non-fluoropolymer B2 described later is 85% by mass or more, and the present lamination It is preferably 90% by mass or more, more preferably 95% by mass or more, from the viewpoint of better dimensional stability after the body is used in a high-temperature environment.
Here, the sum of the cross-linked product of the fluorocopolymer B1 and the cross-linked product of the non-fluoropolymer B2 means that when the second crosslinked layer does not contain the cross-linked product of the non-fluoropolymer B2, It means the content of the crosslinked product of the polymer B1.
_MCB is preferably 100% by weight. That is, the second crosslinked layer preferably does not contain a crosslinked product of the non-fluoropolymer B2. As a result, the dimensional stability after the laminate is used in a high-temperature environment is more excellent, and warping can be suppressed.

The methods for measuring the content of the crosslinked product of the fluorocopolymer B1 and the content of the non-fluoropolymer B2 in the second crosslinked layer are as described in Examples below.

The absolute value of the difference between the M _CA and the M _CB is preferably 15% by mass or less, more preferably 10% by mass or less, from the viewpoint of suppressing the occurrence of warping after the laminate is stored in a high-temperature environment. , 5% by mass or less is more preferable.

The content of the crosslinked product of the fluorine-containing copolymer B1 is 60 to 90 mass with respect to the total mass of the second crosslinked layer, since the dimensional stability of the laminate after use in a high temperature environment is superior. %, more preferably 65 to 90% by mass, even more preferably 70 to 83% by mass.

(Physical properties of fluorine-containing copolymer B1)
The Tg of the fluorine-containing copolymer B1 is preferably 15° C. or less, preferably −30 to 15° C. or less, and −20 to 10°C or less is more preferable.

(Method for producing fluorine-containing copolymer B1)
An example of the method for producing the fluorine-containing copolymer B1 includes a method of polymerizing the above monomers in the presence of a chain transfer agent and a radical polymerization initiator.
The method for producing the fluorocopolymer B1 is the same as the method for producing the fluorocopolymer A1 described above, except that the combination of monomers used is different from the combination of monomers used in the method for producing the fluorocopolymer A1. The manufacturing method is the same, and the preferred embodiments are also the same.

<Non-fluoropolymer B2>
The non-fluoropolymer B2 is a polymer containing no fluorine atoms, and preferably exhibits rubber properties by cross-linking. That is, the crosslinked product of the non-fluoropolymer B2 preferably exhibits rubber properties.
Specific examples of the non-fluoropolymer B2 are the same as those of the non-fluoropolymer A2, and preferred embodiments are also the same.

The crosslinked product of non-fluoropolymer B2 can be obtained, for example, by heating non-fluoropolymer B2 described above in the presence of a crosslinking agent or the like described later.
Here, since the crosslinked product of the non-fluoropolymer B2 is an optional component, the second crosslinked layer may or may not contain the crosslinked product of the non-fluoropolymer B2.
The content of the crosslinked product of the non-fluoropolymer B2 is 15% by mass or less with respect to the total mass of the second crosslinked layer, from the viewpoint that the dimensional stability after the laminate is used in a high temperature environment is more excellent. It is preferably 10% by mass or less, more preferably 0% by mass (that is, the second crosslinked layer does not contain the crosslinked product of the non-fluoropolymer B2).

The Tg of the non-fluoropolymer B2 is preferably 15° C. or less, preferably −50 to 15° C., and −30 to 10° C., from the viewpoint that the properties of the crosslinked product of the non-fluoropolymer B2 as a rubber are sufficiently expressed. more preferred.

<Other ingredients>
The second crosslinked layer may contain components other than the crosslinked product of the fluorine-containing copolymer B1 and the crosslinked product of the non-fluoropolymer B2. Specific examples of such components include an uncrosslinked fluorocopolymer B1 (that is, the above-mentioned fluorocopolymer B1), an uncrosslinked non-fluoropolymer B2 (that is, the above-mentioned non-fluorinated polymer coalescence B2), unreacted cross-linking agent, sintered diatomaceous earth, and silica. Specific examples of the cross-linking agent, sintered diatomaceous earth and silica are the same as the cross-linking agent, sintered diatomaceous earth and silica described in the section of the first cross-linked layer, and preferred embodiments are also the same.
Further, since specific examples of other components other than the above are the same as the components described in the section of the first crosslinked layer, description thereof will be omitted.

When the second crosslinked layer contains other components, the content of the other components is preferably 15 to 40% by mass, more preferably 18 to 30% by mass, more preferably 19 to 30% by mass, based on the total mass of the second crosslinked layer. 29% by mass is more preferred.

When the second crosslinked layer contains a sintered body of diatomaceous earth, the content of the sintered body of diatomaceous earth is less than that of the fluorine-containing copolymer B1 because the adhesion between the first crosslinked layer and the second crosslinked layer is more excellent. It is preferably 1 to 15 parts by mass, more preferably 3 to 15 parts by mass, even more preferably 5 to 15 parts by mass, relative to 100 parts by mass of the crosslinked product.
When the second crosslinked layer contains a sintered body of diatomaceous earth, the content of the sintered body of diatomaceous earth is preferably 1 to 13% by mass, more preferably 2 to 12% by mass, based on the total mass of the second crosslinked layer. Preferably, 4 to 11% by mass is more preferable.

When the second crosslinked layer contains silica, the content of silica is 100 parts by mass of the crosslinked product of the fluorine-containing copolymer B1, since it can further improve the adhesion between the first crosslinked layer and the second crosslinked layer. On the other hand, 1 to 15 parts by mass is preferable, 3 to 15 parts by mass is more preferable, and 5 to 15 parts by mass is even more preferable.
When the second crosslinked layer contains silica, the content of silica is 1 to 10 with respect to the total mass of the second crosslinked layer, since the adhesion between the first crosslinked layer and the second crosslinked layer can be further improved. % by mass is preferable, 3 to 10% by mass is more preferable, and 5 to 9% by mass is even more preferable.

The second crosslinked layer preferably contains both the sintered body of diatomaceous earth and silica. As a result, the adhesion between the first crosslinked layer and the second crosslinked layer is particularly excellent for the same reason as in the case where the first crosslinked layer contains a sintered body of diatomaceous earth and silica.
When the second crosslinked layer contains sintered diatomaceous earth and silica, the ratio of the sintered diatomaceous earth and silica content (sintered diatomaceous earth/silica) is the ratio of the first crosslinked layer and the second crosslinked layer From the viewpoint of better adhesion, 1-15/1-15 is preferred, 3-15/3-15 is more preferred, and 5-15/5-15 is even more preferred.

From the viewpoint of better adhesion between the first crosslinked layer and the second crosslinked layer, at least the first crosslinked layer contains both a sintered body of diatomaceous earth and silica, and the fluorine-containing copolymer in the second crosslinked layer It is preferred that B1 has at least one of an iodine atom and a bromine atom.

[Use]
The laminate can be used, for example, as hoses, seals, valves, rolls, and coatings. This laminate can be used in the form of, for example, a cylinder, a sheet, an O-ring, a V-ring, or the like.

Although the use of the present laminate is not particularly limited, it is preferably used as a member in contact with a basic compound.
Basic compounds include, for example, organic bases and inorganic bases. Organic bases include, for example, amines. Amines include, for example, ammonia, ethylenediamine, and tetraalkylammonium hydroxide. Examples of tetraalkylammonium hydroxide include tetramethylammonium hydroxide. Inorganic bases include, for example, alkali metal hydroxides. Examples of alkali metal hydroxides include sodium hydroxide and potassium hydroxide.
This laminate is particularly suitable for use as a member that comes into contact with ammonia. "Contact with ammonia" includes, for example, contact with 100% liquid ammonia and aqueous ammonia solution, and contact with ammonia generated by reactions such as decomposition of compounds. A compound that generates ammonia by a reaction such as decomposition includes urea.
Ammonia is sometimes used to treat fuels and nitrogen oxides in exhaust gases. Since urea is hydrolyzed to generate ammonia, it is sometimes used as a source of ammonia.
Materials that come into contact with basic compounds include equipment for storing, transporting, reacting, or measuring basic compounds, engines and power generators that use basic compounds (especially ammonia and urea) as raw materials, and exhaust gases containing nitrogen oxides. Examples include hoses, sealing materials, valves, etc., used in gas processing equipment.
When the present laminate is used for a member that comes into contact with a basic compound, it is preferable that the second crosslinked layer is arranged so as to come into contact with the basic compound. In particular, if the crosslinked product of the fluorine-containing copolymer B1 contained in the second crosslinked layer is a crosslinked product of a fluorine-containing copolymer having a TFE unit and a propylene unit, it is more excellent in resistance to basic compounds. , is suitably used as a member in contact with a basic compound.

This laminate is also preferably used as a member that comes into contact with fuel. "Contact with fuel" includes contact with liquid fuel and gaseous fuel. Liquid fuel also includes atomized fuel. Members that come into contact with fuel (for example, light oil, gasoline, natural gas, etc.) include hoses, sheets, O-rings, gaskets, etc. used in fuel storage facilities and transportation equipment that uses fuel. Specific examples of members that come into contact with fuel include turbocharger hoses, oil return hoses, exhaust gas hoses, EGR hoses, oil hoses, and fuel hoses.
When the laminate is used as a member that comes into contact with fuel, it is preferable that the second crosslinked layer is arranged so as to come into contact with the fuel.

[Method for manufacturing laminate]
The method for producing the present laminate is not particularly limited. A method of heating a precursor laminate (described later) in which a second composition layer (described later) containing a fluorine-containing copolymer B1 and a cross-linking agent and optionally containing a non-fluoropolymer B2 is disposed. . Thereby, the fluorine-containing copolymer A1 in the first composition layer and the optionally contained non-fluorine polymer A2 are crosslinked to form the first crosslinked layer, and the fluorine-containing copolymer in the second composition layer is crosslinked. The polymer B1 and optionally included non-fluoropolymer B2 are crosslinked to form the second crosslinked layer, and have a first crosslinked layer and a second crosslinked layer disposed on the first crosslinked layer. This laminate is obtained.

The laminate may have a first crosslinked layer, a second crosslinked layer disposed on the first crosslinked layer, and other layers. Main components of other layers include, for example, fluoropolymers, non-fluoropolymers, metals, glass, and carbon. Other layer principal components may be in the form of plates, fibers, woven fabrics or non-woven fabrics.
As the laminate having other layers, for example, a laminate having a first crosslinked layer, a second crosslinked layer arranged on the first crosslinked layer, and another layer arranged on the second crosslinked layer A laminate having a body, another layer, a first crosslinked layer disposed on the other layer, and a second crosslinked layer disposed on the first crosslinked layer. A plurality of other layers may be provided, but the first crosslinked layer is arranged so as to be in contact with the second crosslinked layer.

Specific examples of the method for crosslinking each polymer by heating include heat press crosslinking, steam crosslinking, hot air crosslinking, oil bath crosslinking, and salt bath crosslinking.
The heating temperature is preferably 130 to 180°C, more preferably 140 to 170°C. When heating, the temperature may be raised or lowered stepwise.
The heating time is preferably 10 minutes to 3 hours.
When heat press crosslinking is performed, the pressure is preferably 5 to 30 MPa.

The thicknesses of the first crosslinked layer and the second crosslinked layer in the laminate of the present invention are not particularly limited.
For example, when the laminate of the present invention is used as a hose, the thickness of each of the first crosslinked layer and the second crosslinked layer can be 0.1 to 200 mm, more preferably 0.1 to 150 mm, and 0.1 to 150 mm. 1 to 100 mm is particularly preferred.
For example, when the laminate of the present invention is used as a sealing material, the thickness of each of the first crosslinked layer and the second crosslinked layer can be 10 to 300 mm, more preferably 10 to 200 mm, particularly 10 to 100 mm. preferable.
For example, when the laminate of the present invention is used as a roll, the thickness of each of the first crosslinked layer and the second crosslinked layer can be 10 to 5000 mm, more preferably 10 to 3000 mm, particularly preferably 10 to 2000 mm. .

[Precursor laminate]
A laminate having a first composition layer and a second composition layer disposed on the first composition layer is referred to as a precursor laminate. By cross-linking the fluorine-containing copolymer contained in the precursor laminate of the present invention (hereinafter also referred to as "the present precursor laminate"), the above-described present laminate can be obtained.
The present precursor laminate is a precursor laminate having a first composition layer and a second composition layer disposed on the first composition layer, wherein the first composition layer comprises A fluorine-containing copolymer A1, a cross-linking agent, optionally a non-fluorine polymer A2, wherein the second composition layer comprises a fluorine-containing copolymer B1, a cross-linking agent, and optionally a non-fluorine Contains polymer B2.
Further, in the present precursor laminate, the combination of units based on the monomers constituting the fluorocopolymer A1 and the combination of units based on the monomers constituting the fluorocopolymer B1 are different from each other.
Further, in the present laminate, the content M _PA of the fluorocopolymer A1 is 85% by mass or more with respect to the total of the fluorocopolymer A1 and the non-fluoropolymer A2, and the fluorocopolymer The content _MPB of the fluorine-containing copolymer B1 is 85% by mass or more with respect to the total of the polymer B1 and the non-fluoropolymer B2.

[First composition layer]
The first composition layer contains a fluorine-containing copolymer A1, a cross-linking agent, and optionally a non-fluorine polymer A2. The details of the fluorine-containing copolymer A1, the cross-linking agent, and the non-fluorine polymer A2 are the same as those described in the section on the first crosslinked layer, so description thereof will be omitted.
The first composition layer may contain components other than the fluorocopolymer A1, the cross-linking agent and the non-fluoropolymer A2. The details of the other components are as described in the section on the first crosslinked layer, so the description thereof is omitted.

The content M _PA of the fluorocopolymer A1 with respect to the total of the fluorocopolymer A1 and the non-fluoropolymer A2 is 85% by mass or more, and the dimensions of the laminate after use in a high-temperature environment 90% by mass or more is preferable, and 95% by mass or more is more preferable, from the viewpoint of better stability.
Here, the sum of the fluorocopolymer A1 and the non-fluoropolymer A2 is the content of the crosslinked product of the fluorocopolymer A1 when the first composition layer does not contain the non-fluoropolymer A2. means quantity.
M _PA is particularly preferably 100% by weight. That is, it is particularly preferable that the first composition layer does not contain the non-fluoropolymer A2. Thereby, the dimensional stability after using the present laminate in a high-temperature environment is more excellent.

The content of the fluorine-containing copolymer A1 is 60 to 90% by mass with respect to the total mass of the first composition layer, since the dimensional stability of the laminate after use in a high-temperature environment is better. Preferably, 64 to 90 mass % is more preferable, and 68 to 83 mass % is even more preferable.

The content of the cross-linking agent is preferably 0.1 to 5.0 parts by mass, and 0.5 part by mass, based on 100 parts by mass of the fluorocopolymer A1, in order to sufficiently cross-link the fluorocopolymer A1. 4.0 parts by mass is more preferable, and 1.0 to 3.0 parts by mass is even more preferable.
The content of the cross-linking agent is preferably 0.1 to 1.5% by mass, more preferably 0.3 to 1.5% by mass, based on the total mass of the first composition layer, in order to sufficiently crosslink the fluorine-containing copolymer A1. 0.2 mass % is more preferred, and 0.5 to 1.0 mass % is even more preferred.

The content of other components is preferably 20 to 32% by mass, more preferably 20 to 31% by mass, and even more preferably 20 to 30% by mass, relative to the total mass of the first composition layer.

Among other components, the first composition layer preferably contains at least one of a sintered body of diatomaceous earth and silica, and preferably contains both. Thereby, the adhesiveness of a 1st crosslinked layer and a 2nd crosslinked layer can be improved more.

The content of the sintered body of diatomaceous earth is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the fluorine-containing copolymer A1 in terms of better adhesion between the first crosslinked layer and the second crosslinked layer. , more preferably 2 to 10 parts by mass, and even more preferably 5 to 10 parts by mass.
The content of the sintered body of diatomaceous earth is preferably 1 to 10% by mass, more preferably 2 to 9% by mass, and even more preferably 3 to 8% by mass, relative to the total mass of the first composition layer.

The content of silica is preferably 1 to 10 parts by mass, preferably 2 to 10 parts by mass, with respect to 100 parts by mass of the fluorine-containing copolymer A1, from the viewpoint of better adhesion between the first crosslinked layer and the second crosslinked layer. Parts by weight are more preferred, and 5 to 10 parts by weight is even more preferred.
The content of silica is preferably 1 to 10% by mass, preferably 2 to 9% by mass, based on the total mass of the first composition layer, from the viewpoint of better adhesion between the first crosslinked layer and the second crosslinked layer. is more preferred, and 3 to 8% by mass is even more preferred.

The content of each component in the first composition layer is calculated based on the charge amount of each component contained in the first composition, which will be described later.

[Second composition layer]
The second composition layer contains a fluorine-containing copolymer B1, a cross-linking agent, and optionally a non-fluorine polymer B2. The details of the fluorine-containing copolymer B1, the cross-linking agent, and the non-fluorine polymer B2 are as described in the section on the second cross-linked layer, so description thereof will be omitted.
The second composition layer may contain components other than the fluorine-containing copolymer B1, the cross-linking agent, and the non-fluorine polymer B2. The details of the other components are as described in the section on the second crosslinked layer, so the description thereof is omitted.

The content M _PB of the fluorocopolymer B1 with respect to the total of the fluorocopolymer B1 and the non-fluoropolymer B2 is 85% by mass or more, and the dimensions of the laminate after being used in a high-temperature environment 90% by mass or more is preferable, and 95% by mass or more is more preferable, from the viewpoint of better stability.
Here, the sum of the fluorocopolymer B1 and the non-fluoropolymer B2 means the content of the crosslinked product of the fluorocopolymer B1 when the second composition layer does not contain the non-fluoropolymer B2. means quantity.
_MPB is particularly preferably 100% by weight. That is, it is particularly preferable that the second composition layer does not contain the non-fluoropolymer B2. Thereby, the dimensional stability after using the present laminate in a high-temperature environment is more excellent.

The content of the fluorine-containing copolymer B1 is 60 to 90% by mass with respect to the total mass of the second composition layer, from the viewpoint of better dimensional stability after the laminate is used in a high-temperature environment. Preferably, 65 to 90% by mass, and even more preferably 70 to 83% by mass.

The content of the cross-linking agent is preferably 0.1 to 5.0 parts by mass, preferably 0.5 parts by mass, with respect to 100 parts by mass of the fluorocopolymer B1, in order to sufficiently cross-link the fluorocopolymer B1. 4.0 parts by mass is more preferable, and 1.0 to 3.0 parts by mass is even more preferable.
The content of the cross-linking agent is preferably 0.1 to 1.5% by mass, more preferably 0.3 to 1.5% by mass, based on the total mass of the second composition layer, in order to sufficiently crosslink the fluorine-containing copolymer B1. 0.3 mass % is more preferred, and 0.5 to 1.2 mass % is even more preferred.

The content of other components is preferably 15-40% by mass, more preferably 18-30% by mass, and even more preferably 19-29% by mass, relative to the total mass of the second composition layer.

Among other components, the second composition layer preferably contains at least one of a sintered body of diatomaceous earth and silica, and preferably contains both. Thereby, the adhesiveness of a 1st crosslinked layer and a 2nd crosslinked layer can be improved more.

The content of the sintered body of diatomaceous earth is preferably 1 to 15 parts by mass with respect to 100 parts by mass of the fluorine-containing copolymer B1 from the viewpoint of better adhesion between the first crosslinked layer and the second crosslinked layer. , more preferably 3 to 15 parts by mass, and even more preferably 5 to 15 parts by mass.
The content of the sintered body of diatomaceous earth is preferably 1 to 13% by mass, more preferably 2 to 12% by mass, and even more preferably 4 to 11% by mass, relative to the total mass of the second composition layer.

The content of silica is preferably 1 to 15 parts by mass, preferably 3 to 15 parts by mass, with respect to 100 parts by mass of the fluorine-containing copolymer B1, from the viewpoint of better adhesion between the first crosslinked layer and the second crosslinked layer. Part by weight is more preferred, and 5 to 15 parts by weight is even more preferred.
The content of silica is preferably 1 to 10% by mass, more preferably 3 to 10% by mass, based on the total mass of the second composition layer, from the viewpoint of better adhesion between the first crosslinked layer and the second crosslinked layer. is more preferred, and 5 to 9% by mass is even more preferred.

The content of each component in the second composition layer is calculated based on the charge amount of each component contained in the second composition, which will be described later.

The absolute value of the difference between the M _PA and the M _PB is preferably 15% by mass or less, more preferably 10% by mass or less, in order to suppress the occurrence of warping after the laminate is stored in a high-temperature environment. , 0 mass % is more preferable.

From the viewpoint of better adhesion between the first crosslinked layer and the second crosslinked layer, at least the first composition layer contains both a sintered diatomaceous earth and silica, and the fluorine-containing co-polymer in the second composition layer Polymer B1 preferably has at least one of an iodine atom and a bromine atom.

[Method for producing precursor laminate]
The method for producing the present precursor laminate is not particularly limited. A first composition layer obtained by forming each of a coalescence B1 and a second composition containing a cross-linking agent and optionally containing a non-fluoropolymer B2 into a sheet shape and using the first composition Above, there is a method of laminating a second composition layer obtained using a second composition.
Further, as another method for producing the present precursor laminate, for example, the first composition and the second composition are extruded simultaneously or sequentially, and the first composition is used. A method of laminating a second composition layer obtained using a second composition on the first composition layer can be mentioned.
Furthermore, a method of laminating by winding the first composition around an iron core to form a first composition layer and then winding the second composition thereon to form a second composition layer can also be used.

The precursor laminate may have a first composition layer, a second composition layer disposed on the first composition layer, and other layers. The details of the other layers are the same as those described in the method for manufacturing the laminate, and thus the description thereof is omitted.

In the method for manufacturing the precursor laminate, the first composition and the second composition may be heated. In this case, it is preferable to heat at a temperature at which the polymer contained in each composition is not crosslinked.

The first composition used for forming the first composition layer contains the fluorine-containing copolymer A1 and a cross-linking agent, and may optionally contain the non-fluorine polymer A2 and other components.
Details of each component contained in the first composition are the same as those of each component contained in the first composition layer, and thus description thereof is omitted.
Since the content of each component in the first composition is the same as the content of each component in the first composition layer, the description thereof is omitted.

The second composition used for forming the second composition layer contains the fluorine-containing copolymer B1 and a cross-linking agent, and may optionally contain the non-fluorine polymer B2 and other components.
Details of each component contained in the second composition are the same as those of each component contained in the second composition layer, and thus description thereof is omitted.
The content of each component in the second composition is the same as the content of each component in the second composition layer, so description thereof will be omitted.

The present invention will be described in detail below with examples. Examples 1 to 8 and 11 are examples, and Examples 9 to 10 are comparative examples. Examples 12 and 13 are reference examples regarding chemical resistance (resistance to basic compounds). However, the present invention is not limited to these examples. In addition, the compounding amount of each component in the table to be described later indicates a mass standard.

<Measurement method>
(Polymerization composition of fluorine-containing copolymer)
The proportion (mol %) of each unit constituting the fluorine-containing copolymer was determined by ¹⁹ F-nuclear magnetic resonance (NMR) analysis, fluorine content analysis, and infrared absorption spectrum analysis.

(Iodine content of fluorine-containing copolymer)
The iodine content of the fluorine-containing copolymer was quantified using an apparatus combining an automatic sample combustion apparatus, an ion chromatograph pretreatment apparatus (manufactured by Mitsubishi Chemical Analytech, model AQF-100) and an ion chromatograph.

(Storage shear modulus G' of fluorine-containing copolymer)
Using a rubber processing analyzer (RPA-2000, manufactured by Alpha Technologies), measurements were made according to ASTM D5289 and D6204 at a temperature of 100° C., an amplitude of 0.5 degrees, and a frequency of 50 cycles/minute.

(Mooney viscosity of fluorine-containing copolymer)
Using a Mooney Viscometer (Shimadzu Corporation, SMV-201), according to JIS K6300-1: 2013, using an L-shaped rotor with a diameter of 38.1 mm and a thickness of 5.54 mm, preheating at 100 ° C. Measurements were made by setting the rotor rotation time to 1 minute and 4 minutes.

(Content of crosslinked product)
The content of the crosslinked fluorocopolymer and the content of the crosslinked non-fluoropolymer in each crosslinked layer were determined as follows. First, the mass of the precursor laminate and the mass of the laminate after cross-linking were measured to confirm that there was no mass loss. All fluorine-containing copolymers are cross-linked products of fluorine-containing copolymers, and all non-fluoropolymers are cross-linked products of non-fluoropolymers. The polymer content was defined as the content of the crosslinked fluorocopolymer and the content of the crosslinked non-fluoropolymer in each crosslinked layer.

<Each component>
Fluorine-containing copolymer 1: Tecnoflon P757, manufactured by Solvay, a fluorine-containing copolymer having VdF units, TFE units and HFP units, the proportion of fluorine atoms in the copolymer is 67% by mass, Mooney viscosity at 121°C = 45 . The fluorine-containing copolymer 1 contains iodine atoms.
Fluorine-containing copolymer 2: a fluorine-containing copolymer containing TFE units and propylene units, the ratio of TFE units to the total of all units constituting the copolymer is 56 mol%, and the ratio of propylene units is 44 mol% . Fluorine-containing copolymer 2 was produced by the method disclosed in WO 2009/119202.
Fluorine-containing copolymer 3: AFLAS (registered trademark) 150P, manufactured by AGC, a fluorine-containing copolymer containing TFE units and propylene units and containing no iodine or bromine atoms. G'=220 kPa, Mooney viscosity=95.

Non-fluoropolymer 1: VAMAC (registered trademark) DP, manufactured by ChemoursDupont, ethylene-acrylate copolymer Non-fluoropolymer 2: Esprene (registered trademark) E 501A, manufactured by Sumitomo Chemical Co., ethylene-propylene-diene copolymer polymer

Perhexa (registered trademark) 25B: cross-linking agent, organic peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, manufactured by NOF Corporation Parkerdox (registered trademark) 14: cross-linking agent, Organic peroxide, α,α'-bis-(tert-butylperoxy)diisopropylbenzene, manufactured by Kayaku Akzo Co., Ltd.

　TAIC (registered trademark): cross-linking aid, triallyl isocyanurate, 1,3,5-triallyl isocyanurate, manufactured by Mitsubishi Chemical Corporation

Calcium stearate: acid acceptor, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. o-Phenylphenol: scorch retardant, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. THENMAX (registered trademark) N-990: filler, carbon black, MT, Canarb Limited Kyowamag (registered trademark) MF-150: acid acceptor, magnesium oxide, manufactured by Kyowa Chemical Industry Co., Ltd. Zinc oxide: acid acceptor, manufactured by Seido Chemical Co., Ltd.

Celite (registered trademark) 350: sintered diatomaceous earth, manufactured by Celite Corporation AEROSIL (registered trademark) 300: hydrophilic silica, manufactured by Nippon Aerosil Co., Ltd.

<Preparation of first composition and second composition>
First compositions a1 to a5 and second compositions b1 to b5 were prepared by uniformly kneading each compounding agent using two rolls at the mass ratios shown in Tables 1 and 2.

In Table 1, "the content of the fluorocopolymer in the total polymer" means the content of the fluorocopolymer ( mass %). The value of "the content of the fluorocopolymer in the total polymer" is the total of the crosslinked product of the fluorocopolymer and the crosslinked product of the non-fluorinated polymer in the first crosslinked layer. It is the same as the content of the crosslinked product of the copolymer (M _CA described above), and the content of the fluorocopolymer with respect to the total of the fluorocopolymer and the non-fluoropolymer in the first composition layer (M _PA above).
In Table 1, "content of fluorocopolymer in composition" means the content (% by mass) of fluorocopolymer with respect to the total mass of the composition. The value of the "content of the fluorocopolymer in the composition" is the same as the content (% by mass) of the crosslinked product of the fluorocopolymer in the first crosslinked layer, and the first composition It was the same as the content (% by mass) of the fluorine-containing copolymer in the layer.

In Table 2, "the content of the fluorocopolymer in the total polymer" means the content of the fluorocopolymer ( mass %). The value of "the content of the fluorocopolymer in the total polymer" is the total of the crosslinked product of the fluorocopolymer and the crosslinked product of the non-fluorinated polymer in the second crosslinked layer. It is the same as the content of the crosslinked product of the copolymer (M _CB described above), and the content of the fluorine-containing copolymer with respect to the total of the fluorine-containing copolymer and the non-fluorine polymer in the second composition layer (M _PB above).
In Table 2, "content of fluorine-containing copolymer in the composition" means the content (% by mass) of the fluorine-containing copolymer with respect to the total mass of the composition. The value of "content of the fluorocopolymer in the composition" is the same as the content (% by mass) of the crosslinked product of the fluorocopolymer contained in the second crosslinked layer. It was the same as the content (mass%) of the fluorine-containing copolymer in the product.

[Examples 1 to 11]
Laminates were produced by combining the first composition and the second composition as shown in Table 3, and each evaluation was performed by the tests described later.

<Evaluation of dimensional stability and warpage>
(Preparation of laminate (test piece) for evaluation)
A test piece for evaluating dimensional stability was prepared by the following procedure.
First, each of the first composition and the second composition was molded into a size of 120 mm long×105 mm wide×1.3 mm thick, and laminated in the combination shown in Table 3. As a result, the precursor laminate including the first composition layer that is the molded body of the first composition and the second composition layer that is disposed on the first composition layer and is the molded body of the second composition got a body
The precursor laminate was placed in a mold and held in a hot press at 170° C. under a pressure of 100 kgf (=9.8 MPa) for 15 minutes for cross-linking to obtain laminates of Examples 1 to 11. Each of the obtained laminates had a size of 130 mm in length×120 mm in width×2 mm in thickness.
The resulting laminate was punched out with a No. 3 dumbbell in accordance with JIS K6251:2004, and a hole with a diameter of 5 mm was made at a distance of 1 cm from the edge to obtain a test piece for evaluation.

(Confirmation of dimensional stability and warpage after heating)
From the point of view of maintaining the performance of the device in which the laminate is incorporated, it is required that the dimensional change of the laminate be kept within a certain range. Therefore, as one index of heat resistance, the dimensional stability and warpage of the laminated body after heating were confirmed.
First, the length of the test piece before heating was measured. It should be noted that the test piece before heating was not bent, and when the test piece was placed on a flat surface, the test piece was parallel to that surface.
The hole of the test piece was hung on a metal hook, and the test piece suspended on the hook was placed in a hot air precision oven (manufactured by Yamato Scientific Co., Ltd.) heated to 240° C. and heated. The samples were removed from the oven after 264 hours. The test piece after heating was air-cooled to the extent that it could be touched with bare hands.
The length of the test piece after heating was measured, and the length of the test piece after heating when the length of the test piece before heating was taken as 100 was taken as the dimension retention rate. Table 3 shows the results. The closer the dimensional retention value is to 100, the better the dimensional stability after heating.
Also, when the heated test piece was placed on a flat surface, the angle between the flat surface and the test piece was measured. Table 3 shows the results. When the test piece is placed on a flat surface, it is 0° if the test piece is parallel to the surface, and 90° if it is bent vertically. The closer the angle is to 0°, the smaller the warpage of the laminate after heating.

<Evaluation of adhesiveness>
(Preparation of laminate (test piece) for evaluation)
A test piece used in the peel test was prepared by the following procedure. First, each of the first composition and the second composition was molded into a size of 120 mm long×105 mm wide×1.3 mm thick, and laminated in the combination shown in Table 3. As a result, the precursor laminate including the first composition layer that is the molded body of the first composition and the second composition layer that is disposed on the first composition layer and is the molded body of the second composition got a body In addition, when the precursor laminate is crosslinked to obtain the laminate, the first composition layer and the When laminating the second composition layer, a release film was sandwiched between the first composition and the second composition.
The precursor laminate with the release film sandwiched therebetween was placed in a mold, and a pressure of 100 kgf (=9.8 MPa) was held for 15 minutes in a hot press at 170 ° C. to perform cross-linking, and each of Examples 1 to 11. A laminate was obtained. Each of the obtained laminates had a size of 130 mm in length×120 mm in width×2 mm in thickness.
The laminate thus obtained was cut in the width direction to obtain a test piece of length 120 mm×width 25 mm×thickness 2 mm, having a non-adhered holding portion extending 40 mm in the length direction from the end of the short side. Four test pieces were subjected to a peeling test, which will be described later.

(Peeling test)
A T-type peel test (JIS K6854-3: 1999) was performed on the test pieces prepared from the laminates of Examples 1 to 11.
The gripped part of the test piece of Examples 1 to 11 is set in a T-type peel tester, and the first crosslinked layer and the second crosslinked layer of the test piece are separated at a speed of 50 mm per minute at a temperature of 25 ° C. and 150 ° C. The maximum peel strength between the first crosslinked layer and the second crosslinked layer was measured as the interlayer adhesion at each temperature. Table 3 shows the results. The greater the peel strength, the more excellent the adhesion between the first crosslinked layer and the second crosslinked layer.

<Evaluation of low temperature resistance>
(Low temperature resistance test)
Using a low-temperature elastic recovery tester, commonly known as TR tester (manufactured by Yasuda Seiki Seisakusho), the adhesiveness (whether or not there is peeling) at low temperatures was confirmed. A laminate was produced in the same manner as in the preparation of test pieces for evaluation of dimensional stability and warpage, and the obtained laminate was cut to obtain a test piece of length 65 mm×width 6 mm×thickness 2 mm.
A test piece was set in a sample holder in the TR tester, and the set test piece was stretched by 10%. The test piece elongated by 10% was immersed together with the sample holder in a tank containing ethanol at −40° C. and allowed to stand for 10 minutes. After 10 minutes had passed, the temperature was raised at a rate of 1°C/min, and the temperature elevation was terminated when the temperature reached 25°C. The test piece was taken out, and the presence or absence of delamination was confirmed by visual observation and light pulling by hand.

Laminates of Examples 1 to 8 and 11 obtained using the first composition and the second composition containing 85% by mass or more of the fluorine-containing copolymer with respect to the total of the fluorine-containing copolymer and the non-fluorine polymer It was confirmed that the body had good dimensional stability even after being kept at 240° C. for 264 hours.
The laminates of Examples 9 and 10 obtained by using the first composition and the second composition containing less than 85% by mass of the fluorocopolymer and the non-fluoropolymer with respect to the total of the fluorocopolymer and the non-fluoropolymer , had poor dimensional stability after being held at 240° C. for 264 hours.
It can be confirmed that the laminates of Examples 1 to 6 and 11 obtained using the first composition and the second composition that do not contain a non-fluoropolymer show little warpage even after being held at 240° C. for 264 hours. rice field.
The laminates of Examples 5 and 6, which have a first composition layer containing the fluorine-containing copolymer 1, silica, and celite, and a second composition layer containing the fluorine-containing copolymer having an iodine atom, The interlayer adhesion at 25°C and 150°C was also excellent.

[Examples 12 and 13]
<Evaluation of chemical resistance>
Using a TAF-SR type PTFE inner cylindrical closed container (manufactured by Pressure Glass Industry Co., Ltd.) with a heat resistance temperature of 180 ° C., a pressure resistance of 7.5 MPa, and an internal volume of 300 cc, the test piece is treated with an aqueous sodium hydroxide solution, an aqueous ammonia solution, or ethylenediamine. (hereinafter also referred to as “chemical solution”) to examine chemical resistance (resistance to basic compounds).

(Preparation of test piece)
A test piece used in the chemical resistance test was prepared by the following procedure. The composition shown in Table 4 was molded to a thickness of 2 mm, and crosslinked by holding for 15 minutes at a pressure of 100 kgf (= 9.8 MPa) in a hot press at 170 ° C., and the resulting crosslinked product was measured according to JIS K6251: 2004. Four test pieces punched out with a No. 3 dumbbell were used as test pieces for measuring tensile strength, tensile elongation and hardness.
In addition, an O-ring obtained by cross-linking the composition shown in Table 4 to form a P26 O-ring of JIS B 2401-1:2012 was used as a test piece for measuring the volume.

Tensile strength, tensile elongation, hardness, and volume were measured for the test piece before being immersed in the chemical solution.
Based on JIS K6251:2017, the tensile strength and tensile elongation of the above No. 3 dumbbell were measured. As a measuring device, a tensile tester with data processing (Quick Reader TS-2530, manufactured by Ueshima Seisakusho Co., Ltd.) was used.
The hardness (Shore-A) of the above No. 3 dumbbell was measured according to JIS K6253-3:2012. As a measuring device, an automatic hardness tester for rubber (Digitest Shore A, manufactured by H. Burleith Testing Instruments Co.) was used. Three No. 3 dumbbells were piled up to a total height of 6 mm, which was placed in a measuring device to measure the hardness.
The volume of the O-ring test piece was measured using a specific gravity meter (DMA-220, manufactured by Shinko Denshi Co., Ltd.) as a measuring device.

Three No. 3 dumbbell test pieces separate from the test pieces for which tensile strength, tensile elongation, and hardness were measured, and the test piece for which the volume was measured were put into the above-mentioned closed container, and then a 50% aqueous sodium hydroxide solution. , or 28% aqueous ammonia solution, or ethylenediamine was introduced. A lid was applied and a vise was used to completely seal the container. The airtight container was placed in an oven set at 70° C. and allowed to stand until 720 hours had passed.
After 720 hours, it was taken out from the oven, cooled to 35°C or less, and the lid of the sealed container was opened. The test piece was taken out, and the chemical adhering to the test piece was washed with water. It was placed on an absorbent cloth to quickly remove water droplets from the surface.
For the ethylenediamine test only, the sealed container was placed in an oven set at 25° C. and allowed to stand for 144 hours. After 144 hours, it was taken out of the oven, the test piece was taken out, and the chemical solution adhering to the test piece was washed with water. It was placed on an absorbent cloth to quickly remove water droplets from the surface.

Tensile strength, tensile elongation, and hardness were measured for three specimens of No. 3 dumbbells after being immersed in the chemical solution. The measurement method is the same as that for the test piece before being immersed in the chemical solution. Arithmetic mean of measurements of three specimens was recorded.
The volume of the O-ring test piece after being immersed in the chemical solution was measured. The measurement method is the same as that for the test piece before being immersed in the chemical solution.

100 + [(Tensile strength of test piece after immersion in chemical solution) - (Tensile strength of test piece before immersion in chemical solution)] / (Tensile strength of test piece before immersion in chemical solution) × 100 Tensile strength retention rate(%),
100 + [(tensile elongation of the test piece after immersion in the chemical solution) - (tensile elongation of the test piece before immersion in the chemical solution)] / (tensile elongation of the test piece before immersion in the chemical solution) x 100 Tensile elongation retention (%),
(Hardness of test piece before immersion in chemical solution) - (Hardness of test piece after immersion in chemical solution) is hardness change,
[(Volume of test piece after immersion in chemical solution) - (Volume of test piece before immersion in chemical solution)] / (Volume of test piece before immersion in chemical solution) x 100 as volume change rate (%) bottom.
Table 4 shows the results.

As shown in Table 4, the crosslinked product of composition b4 exhibited good physical properties even after being immersed in the basic chemical solution. Therefore, if the laminate of the present invention is used in such a manner that the second crosslinked layer containing the crosslinked product of the fluorine-containing copolymer having TFE units and propylene units is in contact with the basic chemical solution, the chemical resistance (basic compound It is expected to be excellent in resistance to
Also, the crosslinked product of composition a1 was greatly deformed or destroyed when immersed in the basic chemical solution. Therefore, in the laminate of the present invention, the second crosslinked layer side containing the crosslinked fluorocopolymer having TFE units and propylene units is in contact with the basic chemical, and the crosslinked fluorocopolymer having VDF units is in contact with the basic chemical solution. Excellent chemical resistance (resistance to basic compounds) is expected if used in such a manner that the first crosslinked layer side containing is not in contact with the basic chemical solution.

In addition, the entire contents of the specification, claims and abstract of Japanese Patent Application No. 2022-017181 filed on February 7, 2022 are cited here and incorporated as disclosure of the specification of the present invention. is.

Claims

A laminate having a first crosslinked layer and a second crosslinked layer disposed on the first crosslinked layer,
wherein the first crosslinked layer contains a crosslinked product of a fluorine-containing copolymer A1 and optionally a crosslinked product of a non-fluoropolymer A2;
the second crosslinked layer comprises a crosslinked fluorocopolymer B1 and optionally a crosslinked non-fluoropolymer B2;
the combination of units based on the monomers constituting the fluorocopolymer A1 and the combination of units based on the monomers constituting the fluorocopolymer B1 are different from each other,
The content M CA of the crosslinked product of the fluorocopolymer A1 with respect to the total of the crosslinked product of the fluorocopolymer A1 and the crosslinked product of the non-fluoropolymer A2 is 85% by mass or more,
The content MCB of the crosslinked product of the fluorocopolymer B1 with respect to the total of the crosslinked product of the fluorocopolymer B1 and the crosslinked product of the non-fluoropolymer B2 is 85% by mass or more. A laminate, characterized in that:
2. The laminate according to claim 1, wherein the absolute value of the difference between said MCA and said MCB is 15% by mass or less.
The fluorine-containing copolymer A1 contains units based on vinylidene fluoride,
The laminate according to claim 1 or 2, wherein the fluorine-containing copolymer B1 contains units based on tetrafluoroethylene and units based on propylene.
The laminate according to any one of claims 1 to 3, wherein at least one of the fluorine-containing copolymer A1 and the fluorine-containing copolymer B1 has at least one of an iodine atom and a bromine atom.
The laminate according to any one of claims 1 to 4, wherein both the fluorine-containing copolymer A1 and the fluorine-containing copolymer B1 have a glass transition temperature of 15°C or less.
The laminate according to any one of claims 1 to 5, wherein at least one of the first crosslinked layer and the second crosslinked layer further contains a sintered body of diatomaceous earth and silica.
wherein the first crosslinked layer does not contain a crosslinked product of the non-fluoropolymer A2,
The laminate according to any one of claims 1 to 6, wherein the second crosslinked layer does not contain a crosslinked product of the non-fluoropolymer B2.
A precursor laminate having a first composition layer and a second composition layer disposed on the first composition layer,
wherein the first composition layer comprises a fluorine-containing copolymer A1, a cross-linking agent, and optionally a non-fluoropolymer A2;
the second composition layer comprises a fluorine-containing copolymer B1, a cross-linking agent, and optionally a non-fluoropolymer B2;
the combination of units based on the monomers constituting the fluorocopolymer A1 and the combination of units based on the monomers constituting the fluorocopolymer B1 are different from each other,
The content M PA of the fluorocopolymer A1 with respect to the total of the fluorocopolymer A1 and the non-fluoropolymer A2 is 85% by mass or more,
A precursor laminate, wherein the content M PB of the fluorine-containing copolymer B1 with respect to the total of the fluorine-containing copolymer B1 and the non-fluorine-containing polymer B2 is 85% by mass or more.
9. The precursor laminate according to claim 8, wherein the absolute value of the difference between the MPA and the MPB is 15% by mass or less.
The fluorine-containing copolymer A1 contains units based on vinylidene fluoride,
10. The precursor laminate according to claim 8, wherein the fluorine-containing copolymer B1 contains units based on tetrafluoroethylene and units based on propylene.
The precursor laminate according to any one of claims 8 to 10, wherein at least one of the fluorine-containing copolymer A1 and the fluorine-containing copolymer B1 has at least one of an iodine atom and a bromine atom.
The precursor laminate according to any one of claims 8 to 11, wherein both the fluorine-containing copolymer A1 and the fluorine-containing copolymer B1 have a glass transition temperature of 15°C or less.
The precursor laminate according to any one of claims 8 to 12, wherein at least one of the first composition layer and the second composition layer further contains a sintered body of diatomaceous earth and silica.
wherein the first composition layer does not contain the non-fluoropolymer A2,
The precursor laminate according to any one of claims 8 to 13, wherein the second composition layer does not contain the non-fluoropolymer B2.