JP6939320B2 - A method for producing a fluoropolymer having a crosslinkable group, a method for producing a curable composition, a fluoropolymer having a crosslinkable group and a curable composition. - Google Patents

Description

The present invention comprises a method for producing a fluoropolymer having a crosslinkable group, a method for producing a curable composition containing a fluoropolymer having a crosslinkable group, a fluoropolymer having a crosslinkable group, and a method for producing a fluoropolymer having a crosslinkable group. The present invention relates to a curable composition containing a fluoropolymer.

A cured product made of a curable composition containing a fluoropolymer has a low dielectric constant, a low refractive index, and is excellent in transparency, water and oil repellency, heat resistance, light resistance, chemical stability, gas permeability, and the like. Therefore, it is used for electronic members (printed substrates, etc.), optical members (optical waveguides, lenses, antireflection films, etc.), water and oil repellency imparting agents, mold release agents, biochips, and the like.

In order to improve the curability of the curable composition containing a fluorine-containing polymer, a crosslinkable group is introduced into the fluorine-containing polymer to improve the crosslinkability of the fluorine-containing polymer. As a method of introducing a crosslinkable group into the fluoropolymer, for example, a method of polymerizing a monomer having a fluorine atom and a monomer having a crosslinkable group, or a monomer having a fluorine atom and a crosslinkable group can be introduced. A method of introducing a crosslinkable group into the group after polymerizing with a monomer having a group can be mentioned.

However, when a crosslinkable group is introduced into the fluoropolymer by the above method, the proportion of units having a crosslinkable group as a pendant group increases, that is, the proportion of units based on a monomer having a fluorine atom decreases, so that the fluoropolymer can be used as a fluoropolymer. Each of the above characteristics may be impaired.

In Patent Document 1, after replacing the -COOH derived from the polymerization initiator at the end of the fluoropolymer having an aliphatic ring structure in -COOCH _3, the -COOCH ₃ amine group-containing silane coupling agent amino It is described that a trimethoxysilyl group is introduced into the terminal of a fluoropolymer having an aliphatic ring structure by reacting a group.

Japanese Unexamined Patent Publication No. 4-226177

However, the fluoropolymer having an aliphatic ring structure described in Patent Document 1 is composed of a linear molecular chain having a high molecular weight, and at most two trimethoxysilyl groups can be introduced per molecular chain. .. Therefore, the fluorine-containing polymer described in Patent Document 1 has poor crosslinkability and insufficient solubility in a solvent, and when used as a solution, a solvent having a very high fluorine content such as a perfluoro compound is used. There is a need.

The present invention relates to a method for producing a fluoropolymer having a crosslinkable group, which does not impair each property as a fluoropolymer and has excellent crosslinkability and solubility, a fluoropolymer having a crosslinkable group, and a fluoropolymer. Provided are a method for producing a curable composition and a curable composition which are excellent in curability and compatibility of each component without impairing each property.

Ｒ ^１１ およびＲ ^１２ は、それぞれ独立に、フッ素原子または炭素数１〜５のペルフルオロアルキル基である。Ｒ ^１３ およびＲ ^１４ は、それぞれ独立に、フッ素原子、炭素数１〜５のペルフルオロアルキル基、または炭素数１〜５のペルフルオロアルコキシ基である。
ＣＦ（Ｒ ^３１ ）＝Ｃ（Ｒ ^３３ ）−Ｏ−ＣＦ（Ｒ ^３６ ）−ＣＦ（Ｒ ^３５ ）−Ｃ（Ｒ ^３４ ）＝ＣＦ（Ｒ ^３２ ） （ｍ２３）
Ｒ ^３１ 〜Ｒ ^３６ は、それぞれ独立に、エーテル結合性酸素原子を有してもよい１価のペルフルオロ有機基またはフッ素原子である。

ただし、Ｒ^１は、エーテル結合性酸素原子を有してもよい１価のペルフルオロ有機基またはフッ素原子であり、Ｒ^２およびＲ^３は、それぞれ独立に、フッ素原子、炭素数１〜５のペルフルオロアルキル基または炭素数１〜５のペルフルオロアルコキシ基であり、Ｒ^４は、５員環の一部または６員環の一部を構成する、エーテル結合性酸素原子を有してもよい直鎖状または分岐状のペルフルオロアルキレン基である。
＜２＞前記架橋性基が、下式（ｇ３）で表される基、エポキシ基、ビニル基および下式（ｇ４）で表される基からなる群から選ばれる少なくとも１種である、前記＜１＞の架橋性基を有する含フッ素ポリマーの製造方法。
−ＯＣＯＣＸ^１＝ＣＨ_２ （ｇ３）
−ＳｉＸ^２ _ｎ（ＯＲ^５）_３−ｎ （ｇ４）
ただし、Ｘ^１は、水素原子、フッ素原子、塩素原子、炭素数１〜４のアルキル基または炭素数１〜４のペルフルオロアルキル基であり、Ｘ^２は、炭素数１〜４のアルキル基であり、ｎは、０〜２の整数であり、Ｒ^５は、炭素数１〜４のアルキル基である。
＜３＞前記架橋性基を有する含フッ素ポリマーの質量平均分子量が、５，０００〜８０，０００である、前記＜１＞または＜２＞のいずれかの架橋性基を有する含フッ素ポリマーの製造方法。
＜４＞前記＜１＞〜＜３＞のいずれかの架橋性基を有する含フッ素ポリマーの製造方法によって架橋性基を有する含フッ素ポリマーを得て、該含フッ素ポリマーを含む硬化性組成物を調製する、硬化性組成物の製造方法。
＜５＞フッ素原子を有する単位として式（ｍ２１）で表されるモノマー、及び式（ｍ２３）で表されるモノマーのいずれか一方又は両方に基づく単位と、含ヨウ素ペルフルオロモノマーに基づく単位とを有する分岐分子鎖からなり、前記分岐分子鎖の複数の末端に架橋性基を有する、架橋性基を有する含フッ素ポリマーを含む、硬化性組成物。

Ｒ ^１１ およびＲ ^１２ は、それぞれ独立に、フッ素原子または炭素数１〜５のペルフルオロアルキル基である。Ｒ ^１３ およびＲ ^１４ は、それぞれ独立に、フッ素原子、炭素数１〜５のペルフルオロアルキル基、または炭素数１〜５のペルフルオロアルコキシ基である。
ＣＦ（Ｒ ^３１ ）＝Ｃ（Ｒ ^３３ ）−Ｏ−ＣＦ（Ｒ ^３６ ）−ＣＦ（Ｒ ^３５ ）−Ｃ（Ｒ ^３４ ）＝ＣＦ（Ｒ ^３２ ） （ｍ２３）
Ｒ ^３１ 〜Ｒ ^３６ は、それぞれ独立に、エーテル結合性酸素原子を有してもよい１価のペルフルオロ有機基またはフッ素原子である。
＜６＞下式（ｇ１１）で表される基および下式（ｇ１２）で表される基のいずれか一方または両方を有する、前記＜５＞の架橋性基を有する含フッ素ポリマーを含む、硬化性組成物。

ただし、Ｒ^１は、エーテル結合性酸素原子を有してもよい１価のペルフルオロ有機基またはフッ素原子であり、Ｒ^２およびＲ^３は、それぞれ独立に、フッ素原子、炭素数１〜５のペルフルオロアルキル基または炭素数１〜５のペルフルオロアルコキシ基であり、Ｒ^４は、５員環の一部または６員環の一部を構成する、エーテル結合性酸素原子を有してもよい直鎖状または分岐状のペルフルオロアルキレン基であり、Ａは、架橋性基を有する基である。
＜７＞前記架橋性基が、下式（ｇ３）で表される基、エポキシ基、ビニル基および下式（ｇ４）で表される基からなる群から選ばれる少なくとも１種である、前記＜５＞または＜６＞のいずれかの架橋性基を有する含フッ素ポリマーを含む、硬化性組成物。
−ＯＣＯＣＸ^１＝ＣＨ_２ （ｇ３）
−ＳｉＸ^２ _ｎ（ＯＲ^５）_３−ｎ （ｇ４）
ただし、Ｘ^１は、水素原子、フッ素原子、塩素原子、炭素数１〜４のアルキル基または炭素数１〜４のペルフルオロアルキル基であり、Ｘ^２は、炭素数１〜４のアルキル基であり、ｎは、０〜２の整数であり、Ｒ^５は、炭素数１〜４のアルキル基である。
＜８＞質量平均分子量が、５，０００〜８０，０００である、前記＜５＞〜＜７＞のいずれかの架橋性基を有する含フッ素ポリマーを含む、硬化性組成物。 The present invention has the following aspects.
<1> A monomer having a fluorine atom and no iodine atom, which is one or both of an iodine-containing perfluoromonomer, a monomer represented by the formula (m21), and a monomer represented by the formula (m23). The monomer component containing and is polymerized to obtain a precursor polymer having either or both of the group represented by the following formula (g1) and the group represented by the following formula (g2), and the lower part of the precursor polymer. A method for producing a fluoropolymer composed of a branched molecular chain having a crosslinkable group, which converts an iodine atom in the formula into a group having a crosslinkable group.

R ¹¹ and R ¹² are independently fluorine atoms or perfluoroalkyl groups having 1 to 5 carbon atoms. R ¹³ and R ¹⁴ are independently a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkoxy group having 1 to 5 carbon atoms.
CF (R ³¹ ) = C (R ³³ ) -O-CF (R ³⁶ ) -CF (R ³⁵ ) -C (R ³⁴ ) = CF (R ³² ) (m23)
R ^{31 to} R ³⁶ are monovalent perfluoroorganic groups or fluorine atoms which may independently have an ether-bonding oxygen atom.

However, R ¹ is a monovalent perfluoroorganic group or a fluorine atom which may have an ether-bonding oxygen atom, and R ² and R ³ are independently a fluorine atom and a perfluoro having 1 to 5 carbon atoms, respectively. an alkyl group or perfluoroalkoxy group having 1 to 5 carbon atoms, R ⁴ constitutes a part of some or 6-membered ring of 5-membered ring, straight chain which may contain an etheric oxygen atom Alternatively, it is a branched perfluoroalkylene group.
< 2 > The crosslinkable group is at least one selected from the group consisting of a group represented by the following formula (g3), an epoxy group, a vinyl group and a group represented by the following formula (g4). 1> A method for producing a fluoropolymer having a crosslinkable group.
-OCOCX ¹ = CH ₂ (g3)
−SiX ² _n (OR ⁵ ) _3-n (g4)
However, X ¹ is a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 4 carbon atoms or a perfluoroalkyl group having 1 to 4 carbon atoms, and X ² is an alkyl group having 1 to 4 carbon atoms. , N is an integer of 0 to 2, and R ⁵ is an alkyl group having 1 to 4 carbon atoms.
< 3 > Production of a fluoropolymer having a crosslinkable group according to either <1> or <2> , wherein the fluoropolymer having a crosslinkable group has a mass average molecular weight of 5,000 to 80,000. Method.
< 4 > A fluoropolymer having a crosslinkable group is obtained by the method for producing a fluoropolymer having a crosslinkable group according to any one of <1> to < 3>, and a curable composition containing the crosslinkable polymer is obtained. A method for producing a curable composition to be prepared.
< 5 > As a unit having a fluorine atom, it has a monomer represented by the formula (m21), a unit based on one or both of the monomers represented by the formula (m23), and a unit based on an iodine-containing perfluoromonomer. A curable composition comprising a fluoropolymer having a crosslinkable group, which comprises a branched molecular chain and has a crosslinkable group at a plurality of ends of the branched molecular chain.

R ¹¹ and R ¹² are independently fluorine atoms or perfluoroalkyl groups having 1 to 5 carbon atoms. R ¹³ and R ¹⁴ are independently a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkoxy group having 1 to 5 carbon atoms.
CF (R ³¹ ) = C (R ³³ ) -O-CF (R ³⁶ ) -CF (R ³⁵ ) -C (R ³⁴ ) = CF (R ³² ) (m23)
R ^{31 to} R ³⁶ are monovalent perfluoroorganic groups or fluorine atoms which may independently have an ether-bonding oxygen atom.
<6> has one or both of the groups represented by groups and the following formula represented by the following formula (g11) (g12), including a fluorine-containing polymer having a crosslinkable group of the <5>, cured Sex composition .

However, R ¹ is a monovalent perfluoroorganic group or a fluorine atom which may have an ether-bonding oxygen atom, and R ² and R ³ are independently a fluorine atom and a perfluoro having 1 to 5 carbon atoms, respectively. an alkyl group or perfluoroalkoxy group having 1 to 5 carbon atoms, R ⁴ constitutes a part of some or 6-membered ring of 5-membered ring, straight chain which may contain an etheric oxygen atom Alternatively, it is a branched perfluoroalkylene group, and A is a group having a crosslinkable group.
<7> The crosslinkable group is at least one selected from the group consisting of groups represented by the group represented by the following formula (g3), an epoxy group, a vinyl group and the following formula (g4), wherein < A curable composition comprising a fluoropolymer having a crosslinkable group of either 5> or <6> .
-OCOCX ¹ = CH ₂ (g3)
−SiX ² _n (OR ⁵ ) _3-n (g4)
However, X ¹ is a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 4 carbon atoms or a perfluoroalkyl group having 1 to 4 carbon atoms, and X ² is an alkyl group having 1 to 4 carbon atoms. , N is an integer of 0 to 2, and R ⁵ is an alkyl group having 1 to 4 carbon atoms.
< 8 > A curable composition comprising a fluoropolymer having a crosslinkable group according to any one of <5 > to < 7 >, which has a mass average molecular weight of 5,000 to 80,000.

According to the method for producing a fluoropolymer having a crosslinkable group of the present invention, a fluoropolymer having a crosslinkable group having excellent crosslinkability and solubility without impairing each property as a fluoropolymer can be produced.
According to the method for producing a curable composition of the present invention, it is possible to produce a curable composition having excellent curability and compatibility of each component without impairing each property as a fluoropolymer.
The fluorine-containing polymer having a crosslinkable group of the present invention is excellent in crosslinkability and solubility without impairing each property as a fluorine-containing polymer.
The curable composition of the present invention is excellent in curability and compatibility of each component without impairing each property as a fluoropolymer.

The monomer represented by the formula (m1) is referred to as a monomer (m1). The group represented by the formula (g1) is referred to as a group (g1). The polymer represented by the formula (p1) is referred to as a polymer (p1). Monomers, groups and polymers represented by other formulas are also described in the same manner.

Unless otherwise specified, the following expressions and definitions of terms apply throughout the specification and claims.
The "unit" means an atomic group based on a monomer formed by radical polymerization of the monomer. The unit may be an atomic group directly formed by a polymerization reaction, or may be an atomic group in which a part of the atomic group is converted into another structure by processing a polymer.
A "monomer" is a compound having a polymerization-reactive carbon-carbon double bond.
The "fluorine-containing polymer" means a polymer having a fluorine atom bonded to a carbon atom.
"Perfluoropolymer" means a polymer in which the ratio of the number of carbon-fluorine bonds to the sum of the number of carbon-halogen bonds and the number of carbon-hydrogen bonds in the polymer is 95% or more. The ratio of the number of carbon-fluorine bonds to the sum of the number of carbon-halogen bonds and the number of carbon-hydrogen bonds in the polymer can be calculated, for example, using the measurement results of elemental analysis.
The "iodine-containing perfluoropolymer" means a polymer in which some of the fluorine atoms of the perfluoropolymer are replaced with iodine atoms.
"Perfluoromonomer" means a monomer in which all hydrogen atoms bonded to carbon atoms have been replaced with fluorine atoms.
The "iodine-containing perfluoromonomer" means a monomer in which a part of the fluorine atom of the perfluoromonomer is replaced with an iodine atom.
By "perfluoroalkyl group" is meant a group in which all hydrogen atoms of the alkyl group have been replaced by fluorine atoms.
"Perfluoroalkylene group" means a group in which all the hydrogen atoms of the alkylene group are replaced with fluorine atoms.
By "branched molecular chain" is meant a molecular chain composed of branched units having at least one bifurcation point. A molecular chain composed of linearly connected units and having a pendant group (a side branch that is not a side chain composed of a plurality of units) is not a branched molecular chain.
"~" Indicating a numerical range means that the numerical values described before and after the numerical range are included as the lower limit value and the upper limit value.

<Method for producing fluoropolymer having crosslinkable group>
In the method for producing a fluoropolymer having a crosslinkable group of the present invention, a specific precursor polymer having an iodine atom is obtained, and the iodine atom of the precursor polymer is converted into a group having a crosslinkable group to obtain a crosslinkable group. This is a method for obtaining a fluoropolymer having a fluoropolymer (hereinafter, also referred to as a fluoropolymer (A1)).

(Precursor polymer)
The precursor polymer includes a monomer having a fluorine atom and an iodine atom (hereinafter, also referred to as a monomer (m1)) and a monomer having a fluorine atom and no iodine atom (hereinafter, also referred to as a monomer (m2)). It is obtained by polymerizing a monomer component containing.

As the monomer (m1), an iodine-containing perfluoromonomer is preferable because the proportion of fluorine atoms in the fluoropolymer (A1) can be increased and the fluoropolymer (A1) having excellent properties as a fluoropolymer can be obtained.
As the monomer (m1), a monomer having a group (g1) described later is preferable because it is easy to convert the iodine atom of the precursor polymer into a group having a crosslinkable group, which is the opposite of the polymerization-reactive carbon-carbon double bond. A monomer having a group (g1) described later at the end on the side is more preferable. By using the above-mentioned monomer, a fluoropolymer having a molecularly branched chain can be obtained.

Examples of the monomer (m1) include the following monomers.
CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF _2- I,
CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF (CF ₃ ) OCF ₂ CF _2- I,
CF ₂ = CFO (CF ₂ ) _2- I,
CF ₂ = CFO (CF ₂ ) _3- I,
CF ₂ = CFO (CF ₂ ) _4- I,
CF ₂ = CFO (CF ₂ ) _5- I,
CF ₂ = CFO (CF ₂ ) _6- I,
CF ₂ = CFO (CF ₂ ) _8- I,
CF ₂ = CFOCF ₂ CF (CF ₃ ) -I,
CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF (CF ₃ ) -I,
CF ₂ = CFO (CF ₂ ) ₃ OCF ₂ CF _2- I,
CF ₂ = CFOCF ₂ CF ₂ OCF ₂ CF ₂ CF ₂ CF _2- I,
CF ₂ = CFOCF (CF ₃ ) CF ₂ OCF ₂ CF _2- I,
CF ₂ = CFOCF ₂ CF ₂ CH _2- I,
CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF ₂ CH _2- I,
CF ₂ = CFOCF ₂ CF ₂ CH ₂ CH ₂ CH _2- I,
CH ₂ = CHCF ₂ CF _2- I,
CH ₂ = CHCF ₂ CF ₂ CF ₂ CF _2- I,
CH ₂ = CFCF ₂ CF _2- I,
CH ₂ = CFCF ₂ CF ₂ CF ₂ CF _2- I,
CH ₂ = CFCF ₂ OCF (CF ₃ ) -I,
CH ₂ = CFCF ₂ OCF (CF ₃ ) CF ₂ OCF (CF ₃ ) -I,
CH ₂ = CFCF ₂ OCF (CF ₃ ) CF ₂ OCF (CF ₃ ) CF ₂ OCF (CF ₃ ) -I.

The monomer (m1) can be synthesized, for example, by the method described in Examples. The monomer (m1) is preferably an iodine-containing perfluoromonomer. Iodine-containing perfluorinated monomer, it is possible to synthesize easily from perfluorinated monomers having general -SO 2 _F group, it can be manufactured inexpensively with the precursor polymer and the fluoropolymer (A1).

As the monomer (m2), a perfluoromonomer is preferable because the proportion of fluorine atoms in the fluoropolymer (A1) can be increased and the fluoropolymer (A1) having excellent properties as a fluoropolymer can be obtained.
The monomer (m2) is a group (g1) or a group (g1) or a group (g1), which will be described later, when an iodine atom is bonded to a unit based on the monomer (m2) because the iodine atom of the precursor polymer can be easily converted into a group having a crosslinkable group. A monomer that can be a unit having g2) is preferable, and the monomer (m20) and the monomer (m23) described later give a fluorine-containing polymer (A1) having good solubility in a solvent, which is more preferable. When the monomer (m20) or the monomer (m23) is contained as a polymerization unit, the obtained polymer tends to be amorphous. Amorphous polymers tend to be more soluble in solvents than crystalline polymers.

Examples of the monomer (m2) include a monomer having an aliphatic ring structure, a monomer capable of forming an aliphatic ring structure by cyclization polymerization, tetrafluoroethylene, chlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, and fluoride. Vinyl, hexafluoropropylene, (perfluoroalkyl) ethylene (eg, (perfluorobutyl) ethylene), (perfluoroalkyl) propene (eg, 3-perfluorooctyl-1-propene), having a fluorine atom and a precursor of an ion exchange group Monomers having a body group can be mentioned.
Examples of the ion exchange group include −SO ₃ ^- Z ⁺ , −COO ⁻ Z ⁺ (where Z ⁺ is H ⁺ , a monovalent metal cation, ammonium ion, etc.) and the like. Examples of the precursor group include -SO ₂ F, -COOR (R is an alkyl group and the like) and the like.

As the monomer (m2), a monomer having an aliphatic ring structure and an aliphatic ring structure are formed by cyclization polymerization because a fluoropolymer (A1) having excellent solubility in a solvent and excellent properties can be obtained. Those containing one or both of possible monomers are preferred.

The aliphatic ring structure may have one or two ether-bonding oxygen atoms, and is a cyclic organic group in which a part or all of hydrogen atoms bonded to carbon atoms are replaced with fluorine atoms.
The polymerization-reactive carbon-carbon double bond in the monomer having an aliphatic ring structure may be composed of two adjacent carbon atoms constituting the aliphatic ring structure, and one constituting the aliphatic ring structure. It may be composed of a carbon atom of the above and one carbon atom existing outside the aliphatic ring structure adjacent thereto.

Examples of the monomer having an aliphatic ring structure include a monomer (m20) and a monomer (m22) described later, and the monomer (m20) is preferable because it can be a unit having a group (g2) described later.
The monomer (m20) is represented by the following formula.

R ^{2, R 3} and ^{R 4} are the same as ^R 2, ^{R 3} and ^{R 4} in later-described group (g2).
As the monomer (m20), the monomer (m21) is preferable from the viewpoint of polymerization reactivity and ease of synthesis.

R ¹¹ and R ¹² are independently fluorine atoms or perfluoroalkyl groups having 1 to 5 carbon atoms.
R ¹³ and R ¹⁴ are independently a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkoxy group having 1 to 5 carbon atoms. At least one of R ¹³ and R ¹⁴ is preferably a fluorine atom, and more preferably both are fluorine atoms, from the viewpoint of high polymerization reactivity of the monomer (m21).
The perfluoroalkyl group and the perfluoroalkoxy group may be linear, may be branched, and are preferably linear.

Examples of the monomer (m21) include monomers (m21-1) to (m21-7).

The monomer (m22) is represented by the following formula.

R ^{21 to} R ²⁶ are monovalent perfluoroorganic groups or fluorine atoms which may independently have an ether-bonding oxygen atom. As the monovalent perfluoroorganic group, a perfluoroalkyl group is preferable. When the perfluoroalkyl group has an ether-bonding oxygen atom, the number of oxygen atoms may be one or two or more. Further, the oxygen atom may be inserted between the carbon-carbon bonds of the perfluoroalkyl group, or may be present at the terminal on the side where the carbon atom forming the ring of the monomer (m22) is bonded. The perfluoroalkyl group may be linear, may be branched, and is preferably linear.
At least one of R ²⁵ and R ²⁶ is preferably a fluorine atom, and more preferably both are fluorine atoms, from the viewpoint of high polymerization reactivity of the monomer (m22).

Examples of the monomer (m22) include a monomer (m22-1) and a monomer (m22-2), and the monomer (m22-1) is preferable from the viewpoint of easy synthesis.

Examples of the monomer capable of forming an aliphatic ring structure by the cyclization polymerization include a monomer (m23).
The monomer (m23) is represented by the following formula.
CF (R ³¹ ) = C (R ³³ ) -O-CF (R ³⁶ ) -CF (R ³⁵ ) -C (R ³⁴ ) = CF (R ³² ) (m23)
R ^{31 to} R ³⁶ are monovalent perfluoroorganic groups or fluorine atoms which may independently have an ether-bonding oxygen atom. As the monovalent perfluoroorganic group, a perfluoroalkyl group is preferable. When the perfluoroalkyl group has an ether-bonding oxygen atom, the number of oxygen atoms may be one or two or more. Further, the oxygen atom may be inserted between the carbon-carbon bonds of the perfluoroalkyl group, or may be present so as to be directly bonded to the carbon atom to which the perfluoroalkyl group is bonded. The perfluoroalkyl group may be linear, may be branched, and is preferably linear.
R ^{31 to} R ³⁴ are more preferably fluorine atoms from the viewpoint of high polymerization reactivity of the monomer (m23).

Examples of the monomer (m23) include monomers (m23-1) to (m23-3), and the monomer (m23-1) is preferable from the viewpoint of easy synthesis.
_{CF 2 = CF-O-CF} 2 -CF 2 -CF = CF 2 (m23-1)
CF ₂ = CF-O-CF ₂ -CF (CF ₃ ) -CF = CF ₂ (m23-2)
CF ₂ = CF-O-CF (CF ₃ ) -CF ₂ -CF = CF ₂ (m23-3)

The monomer (m1) and the monomer (m2) are appropriately selected so that the precursor polymer has one or both of the group (g1) and the group (g2) described later.
The monomer component may contain a third monomer other than the monomer (m1) and the monomer (m2), if necessary, as long as the effects of the present invention are not impaired.
Examples of the third monomer include ethylene, propylene, cyclopentene, norbornene and the like.

The charged molar ratio of the monomer (m1) to the monomer (m2) is in a range in which the molar ratio (m2 / m1) of the unit based on the monomer (m2) and the molecular weight to the unit based on the monomer (m1) in the precursor polymer described later are preferable. It is adjusted appropriately so as to be.

Examples of the polymerization method include known polymerization methods such as a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, and a bulk polymerization method.
The polymerization is carried out under the condition that radicals are generated. Examples of the method for generating radicals include a method of adding a radical initiator, a method of irradiating radiation such as ultraviolet rays, γ-rays, and electron beams.

Examples of the radical initiator include bis (fluoroacyl) peroxide, bis (chlorofluoroacyl) peroxide, dialkyl peroxydicarbonate, diacyl peroxide, peroxy ester, azo compound, and persulfate.

Solvents used in the solution polymerization method include perfluorotrialkylamine (perfluorotributylamine, etc.), perfluorocarbon (perfluorohexane, perfluorooctane, etc.), hydrofluorocarbon (1H, 4H-perfluorobutane, 1H-perfluorohexane, etc.), and hydro. Chlorofluorocarbons (3,3-dichloro-1,1,1,2,2-pentafluoropropane, 1,3-dichloro-1,1,2,2,3-pentafluoropropane, etc.), hydrofluoroethers (CF) ₃ CH ₂ OCF ₂ CF ₂ H, etc.).

In the solution polymerization method, a monomer component, a radical initiator, or the like is added to the solvent, and radicals are generated in the solvent to polymerize the monomer component. The addition of the monomer component and the radical initiator may be a batch addition, a sequential addition, or a continuous addition.

The precursor polymer obtained by polymerizing a monomer component containing a monomer (m1) and a monomer (m2) has one or both of a group (g1) and a group (g2).

R ¹ is a monovalent perfluoroorganic group or fluorine atom which may have an ether-bonding oxygen atom. As the monovalent perfluoroorganic group, a perfluoroalkyl group is preferable. When the perfluoroalkyl group has an ether-bonding oxygen atom, the number of oxygen atoms may be one or two or more. Further, the oxygen atom may be inserted between the carbon-carbon bonds of the perfluoroalkyl group, or may be present at the end of the group (g1) on the side to be bonded to the carbon atom. The perfluoroalkyl group may be linear, may be branched, and is preferably linear. The number of carbon atoms of the perfluoroalkyl group is preferably 1 to 6, and more preferably 1 to 4. The R ^1, a fluorine atom, a trifluoromethyl group or a pentafluoroethyl group is preferred, and more preferably a fluorine atom or a trifluoromethyl group, more preferably a fluorine atom.

R ² and R ³ are independently a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkoxy group having 1 to 5 carbon atoms.
R ⁴ constitutes a part of some or 6-membered ring of 5-membered ring, which may have an etheric oxygen atom linear or branched perfluoroalkylene group. When the perfluoroalkylene group has an ether-bonding oxygen atom, the number of oxygen atoms may be one or two. Further, the oxygen atom may be inserted between carbon-carbon bonds of the perfluoroalkylene group, or may be present at the terminal.

Units having a group (g1) include, for example, a unit based on a monomer (m1) in which an iodine atom has not been released; a unit based on a monomer (m2) (for example, a monomer (m23)) located at the end of a molecular chain. A unit in which an iodine atom is bonded can be mentioned.
Examples of the unit having a group (g2) include a unit in which an iodine atom is bonded to a unit based on a monomer (m2) (for example, a monomer (m20)) located at the end of a molecular chain.
The iodine atom bonded to the unit based on the monomer (m2) is an iodine atom separated from the unit based on the monomer (m1) during the polymerization of the monomer component, or an iodine atom transferred from the monomer (m1) in the polymerization reaction system. Is.

The molar ratio (m2 / m1) of the unit based on the monomer (m2) to the unit based on the monomer (m1) in the precursor polymer is preferably 3/1 to 100/1, more preferably 5/1 to 50/1. When m2 / m1 is equal to or higher than the lower limit of the above range, a fluoropolymer (A1) having excellent properties can be easily obtained. In addition, a sufficiently high molecular weight can be easily obtained during polymerization. When m2 / m1 is not more than the upper limit of the above range, sufficient cross-linking reactivity can be easily obtained in the fluoropolymer (A1). Further, the group having a crosslinkable group makes it easy to obtain the solubility of the fluoropolymer (A1) in a solvent.
The unit based on the monomer (m1) also includes a unit (branch point) obtained by removing the iodine atom from the unit based on the monomer (m1). Further, the unit based on the monomer (m2) also includes a unit based on the monomer (m2) in which an iodine atom is bonded.

The number of iodine atoms per molecule of the polymer in the precursor polymer may be appropriately adjusted according to the balance between the crosslinkability of the fluorine-containing polymer (A1) and each property as the fluorine-containing polymer. When the number of iodine atoms per molecule of the polymer is large, the number of crosslinkable groups in the fluoropolymer (A1) is sufficiently large, and the crosslinkability of the fluoropolymer (A1) is further excellent. If the number of iodine atoms per molecule of the polymer is not too large, the number of crosslinkable groups in the fluoropolymer (A1) is not too large, and each property as a fluoropolymer is not easily impaired.

As the precursor polymer, an iodine-containing perfluoropolymer is preferable from the viewpoint of obtaining a fluoropolymer (A1) having excellent properties as a fluoropolymer.
As the precursor polymer, a polymer having a branched molecular chain is preferable because the number of crosslinkable groups introduced at the end of the molecular chain increases and a fluorine-containing polymer (A1) having excellent crosslinkability and solubility can be obtained.

When the precursor polymer consists of a branched molecular chain, the branching point of the branched molecular chain consists of a unit based on the monomer (m1) minus an iodine atom. The unit based on the monomer (m1) from which an iodine atom is extracted by a radical in the polymerization reaction system during the polymerization of the monomer component becomes the starting point of polymerization, that is, the branching point of the polymer.

The fact that the precursor polymer is a branched molecular chain can be confirmed by NMR measurement by the presence of a peak derived from a unit based on the monomer (m1) and a peak derived from a unit based on the monomer (m2).
When the unit based on the monomer (m1) is the unit based on 8IVE described later, a peak derived from the fluorine atom bonded to the carbon atom to which the iodine atom is bonded can be confirmed in the vicinity of -60 to -65 ppm.
When the unit based on the monomer (m2) is the unit based on the monomer (m20), a peak derived from the fluorine atom bonded to the carbon atom of the aliphatic ring structure to which the iodine atom is bonded can be confirmed, for example, the monomer (m21-). In the case of the unit based on 1), the above peak can be confirmed at around −45 ppm.
When the unit based on the monomer (m2) is the unit based on the monomer (m23), a peak derived from the fluorine atom bonded to the carbon atom to which the iodine atom is bonded can be confirmed. For example, the unit based on the monomer (m23-1). In the case of, the above peak can be confirmed in the vicinity of 455 to -50 ppm.
The chemical shift value is a value when the chemical shift of the solvent perfluorobenzene is set to -162.7 ppm.

The mass average molecular weight of the precursor polymer is preferably 5,000 to 80,000, more preferably 10,000 to 60,000, and even more preferably 15,000 to 40,000. When the mass average molecular weight of the precursor polymer is within the above range, it is easy to obtain a fluoropolymer (A1) having a mass average molecular weight in a preferable range described later. The mass average molecular weight of the present specification is a reduced mass average molecular weight of polymethylmethacrylate (hereinafter referred to as PMMA) obtained by measuring by the method described later. The absolute molecular weight of the polymer having a branched structure measured by a known method such as a light scattering method is larger than the PMMA-equivalent molecular weight.

(Fluororesin-containing polymer (A1))
The fluoropolymer (A1) is obtained by converting the iodine atom of the precursor polymer into a group having a crosslinkable group.
As the fluorine-containing polymer (A1), those in which all the iodine atoms of the precursor polymer react with each other and do not contain iodine atoms are preferable, and those having a high conversion rate of iodine atoms to a group having a crosslinkable group are preferable. .. If iodine atoms remain in the fluoropolymer (A1), the fluoropolymer (A1) is easily deteriorated and colored by iodine liberated by light or heat.

The fluoropolymer (A1) has one or both of the group (g11) and the group (g12).

R ¹ , R ² , R ³ and R ⁴ are similar to ^{R 1} , R ² , R ³ and R ⁴ in the group (g 1) and group (g 2) described above.
A is a group having a crosslinkable group.

The group (g11) is obtained by converting the iodine atom of the above-mentioned group (g1) into a group having a crosslinkable group.
The group (g12) is obtained by converting the iodine atom of the above-mentioned group (g2) into a group having a crosslinkable group.

Examples of the crosslinkable group include a group (g3), an epoxy group, a vinyl group, a group (g4), a cyano group, a maleimide group, an azido group, an ethynyl group, a carboxy group, an alkoxycarbonyl group, an amino group and a hydroxyl group. From the viewpoint of excellent crosslinkability of the fluorine-containing polymer (A1), at least one selected from the group consisting of a group (g3), an epoxy group, a vinyl group and a group (g4) is preferable, and a group (g3), an epoxy group and a group are preferable. At least one selected from the group consisting of (g4) is more preferable. In this specification, the terminal group consisting of iodine atom and bromine atom is excluded from the crosslinkable group.

-OCOCX ¹ = CH ₂ (g3)
−SiX ² _n (OR ⁵ ) _3-n (g4)
However, X ¹ is a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 4 carbon atoms or a perfluoroalkyl group having 1 to 4 carbon atoms, and X ² is an alkyl group having 1 to 4 carbon atoms. , N is an integer of 0 to 2, and R ⁵ is an alkyl group having 1 to 4 carbon atoms.

The conversion of the iodine atom of the precursor polymer to a crosslinkable group can be carried out in the same manner as in known reactions in small molecule compounds.
As a method for converting the iodine atom of the precursor polymer into a group having a group (g3), for example, by the method described in US Pat. No. 4,058,573, the precursor polymer (hereinafter, also referred to as polymer (p0)) is converted to a polymer. (P1) was obtained, and a polymer (p2) was obtained by the method described in JP-A-48-103504, and JP-A-53-139693, US Pat. No. 3,328,905 or JP-A-5-345732. Examples thereof include a method for obtaining a polymer (p3) by the method described in Japanese Patent Publication No.
Further, a polymer (p4) was obtained from the polymer (p0) by the method described in Japanese Patent Publication No. 46-25361, and published in 1994, Vol. 68, No. 1, p. Examples thereof include a method of obtaining a polymer (p6) in the same manner as a method of obtaining a polymer (p5) by the method described in 49-56 or Japanese Patent Application No. 2015-227178.
However, the Polymer in the following formula (p0) is the remainder of the precursor polymer excluding the iodine atom, and is the same in the following formula. ^{X 1} in the formula (p3) and the following equation (p6) is the same as ^{X 1} in the above formula (g3).
Polymer-I (p0)
Polymer-CH ₂ CH ₂ I (p1)
Polymer-CH ₂ CH ₂ OH (p2)
Polymer-CH ₂ CH ₂ OCOCX ¹ = CH ₂ (p3)
Polymer-CH ₂ CHICH ₂ OH (p4)
Polymer-CH ₂ CH ₂ CH ₂ OH (p5)
Polymer-CH ₂ CH ₂ CH ₂ OCOCX ¹ = CH ₂ (p6)
As a method for converting the iodine atom of the precursor polymer into a group having an epoxy group, a polymer (p4) is obtained by the same method as described above, and is described in Japanese Patent Publication No. 46-25361 or Japanese Patent Publication No. 60-55490. The method of obtaining the polymer (p7) can be mentioned. Ep in the formula (p7) is an epoxy group.
Polymer-CH ₂ Ep (p7)
As a method for converting the iodine atom of the precursor polymer into a group having a vinyl group, a polymer (p1) is obtained by the same method as described above, and the Journal of Fluorine Chemistry, 1995, Vol. 74, No. 2, p. A method of obtaining a polymer (p8) by the method described in 191-197 can be mentioned.
Also, Journal of Fluorine Chemistry, 1982, Vol. 20, No. 3, p. Examples thereof include a method of obtaining a polymer (p9) from a polymer (p0) by the method described in 313-327, and further obtaining a polymer (p10) by the method described in JP-A-48-34805.
Tetrahedron Letters, 2001, Vol. 42, No. 5, p. The polymer (p10) may be obtained from the polymer (p0) by the method described in 947-950.
Polymer-CH = CH ₂ (p8)
Polymer-CH ₂ CHICH ₂ OCOCH ₃ (p9)
Polymer-CH ₂ CH = CH ₂ (p10)
As a method for converting the iodine atom of the precursor polymer into a group having a group (g4), Journal of Organic Chemistry, 1962, Vol. 27, p. Obtaining the polymer (p11) from the polymer (p0) by the method described in 2261-2262, JP-A-5-339007 or International Publication No. 2012/081524, International Publication No. 2012/081524 or International Publication No. 2013 A method for obtaining a polymer (p12) by the method described in / 031622 can be mentioned.
Also, Journal of Fluorine Chemistry, 2000, Vol. 104, No. 2, p. The polymer (p12) may be obtained from the polymer (p8) by the method described in 185-194, International Publication No. 2012/081524 or Japanese Patent Application Laid-Open No. 2015-205973.
Journal of Fluorine Chemistry, 2000, Vol. 104, No. 2, p. The polymer (p13) may be obtained from the polymer (p10) by the method described in 185-194.
However, the following equation (pi 1), the ^{X 2} and ^{R 5} in the formula (p12) and the following formula (p13), the same as ^{X 2} and ^{R 5} in the formula (g4).
Polymer-CH ₂ CHISiX ² _n (OR ⁵ ) _3-n (p11)
Polymer-CH ₂ CH ₂ SiX ² _n (OR ⁵ ) _3-n (p12)
Polymer-CH ₂ CH ₂ CH ₂ SiX ² _n (OR ⁵ ) _3-n (p13)

The number of crosslinkable groups per molecule of the fluoropolymer (A1) may be appropriately adjusted according to the balance between the crosslinkability of the fluoropolymer (A1) and each property as the fluoropolymer. If the number of crosslinkable groups per polymer molecule is large, the crosslinkability of the fluoropolymer (A1) is further excellent. Unless the number of crosslinkable groups per polymer molecule is too large, each property as a fluoropolymer is unlikely to be impaired.

As the fluoropolymer (A1), it is preferable that all the units of the fluoropolymer (A1) are units based on a perfluoromonomer or an iodine-containing perfluoromonomer from the viewpoint of being excellent in each property as a fluoropolymer.
The fluoropolymer (A1) is preferably composed of a branched molecular chain from the viewpoint that the number of crosslinkable groups introduced at the end of the molecular chain is large and the crosslinkability and solubility are excellent.

The mass average molecular weight of the fluoropolymer (A1) is preferably 5,000 to 80,000, more preferably 10,000 to 60,000, and even more preferably 15,000 to 40,000. When the mass average molecular weight of the fluoropolymer (A1) is equal to or higher than the lower limit of the above range, the fluorine content of the fluoropolymer (A1) is high, and the properties of the fluoropolymer (A1) are likely to be sufficiently exhibited. .. Further, when the fluoropolymer (A1) is cured by a cross-linking reaction, the strength of the cured product such as a film or a coating film tends to be good. When the mass average molecular weight of the fluorine-containing polymer (A1) is not more than the upper limit of the above range, the solubility of the fluorine-containing polymer (A1) in a solvent is likely to be good, and a solution having a high polymer concentration is likely to be obtained. Further, when the fluoropolymer (A1) is cured by a cross-linking reaction, the reactivity tends to be good.

In the method for producing a fluorine-containing polymer having a crosslinkable group described above, a monomer having a fluorine atom and an iodine atom (m1) and a monomer having a fluorine atom and no iodine atom (m2) ) To obtain a precursor polymer having either one or both of the group (g1) and the group (g2), and convert the iodine atom of the precursor polymer into a group having a crosslinkable group. Since it is a method for obtaining a fluorine-containing polymer (A1), a fluorine-containing polymer (a method for polymerizing a monomer having a fluorine atom and a monomer having a crosslinkable group without a fluorine atom) is used. It is not necessary to reduce the proportion of units based on the monomer having a fluorine atom in A1). Therefore, it is possible to produce a fluoropolymer (A1) in which each property (low dielectric constant, low refractive index, transparency, water repellency, oil repellency, heat resistance, light resistance, chemical stability, gas permeability, etc.) is not impaired. .. In addition, the iodine atom present in the terminal group of the precursor polymer can be converted into various crosslinkable groups. By selecting a crosslinkable group according to the application, there is no particular limitation on the application, but it can be applied to various applications such as electronic members, optical members, water- and oil-repellent imparting agents, mold release agents, and biochips. A fluoropolymer (A1) can be obtained.
Further, in the method for producing a fluoropolymer having a crosslinkable group of the present invention described above, a precursor polymer having a plurality of iodine atoms is obtained, and the iodine atom of the precursor polymer is used as a group having a crosslinkable group. Since it is a method of converting to obtain a fluorine-containing polymer (A1), it is compared with the conventional method (a method of introducing a trimethoxysilyl group at the end of a fluorine-containing polymer having an aliphatic ring structure composed of linear molecular chains). Many crosslinkable groups can be introduced. Therefore, a fluoropolymer (A1) having excellent crosslinkability and solubility can be produced.

<Manufacturing method of curable composition>
The method for producing a curable composition of the present invention is a method of obtaining a fluoropolymer (A1) by the method described above and preparing a curable composition containing the fluoropolymer (A1).

When the fluoropolymer (A1) has a group (g3) or a vinyl group as a crosslinkable group, the curable composition is a photocurable composition containing the fluoropolymer (A1) and a photopolymerization initiator; Examples thereof include a thermosetting composition containing a fluoropolymer (A1) and a thermosetting initiator; a curable composition containing a fluoropolymer (A1), a hydrosilylation cross-linking agent, and a hydrosilylation catalyst.
Examples of the photopolymerization initiator include those described in JP-A-2008-189836, International Publication No. 2013/115191, and the like.
Examples of the thermal polymerization initiator include known radical initiators.
Examples of the hydrosilylation cross-linking agent and the hydrosilylation catalyst include those described in International Publication No. 2011/0655155 and the like.

When the fluoropolymer (A1) has a group (g4) as a crosslinkable group, the curable composition is a photocurable composition containing the fluoropolymer (A1) and a photoacid generator or a photobase generator. Things etc. can be mentioned.
Examples of the photoacid generator include those described in JP-A-2006-169375, International Publication No. 2015/033805, International Publication No. 2015/1633379 and the like.
Examples of the photobase generator include those described in International Publication No. 2015/033805 and the like.
The curable composition may contain an alkoxysilane (tetraalkoxysilane, trialkoxysilane, dialkoxysilane, etc.) as a cross-linking agent.

When the fluoropolymer (A1) has an epoxy group as a crosslinkable group, examples of the curable composition include a curable composition containing the fluoropolymer (A1) and an epoxy curing agent.
As the epoxy curing agent, for example, various curing agents described in the Epoxy Resin Handbook (Nikkan Kogyo Shimbun, published in 1987) can be used. Specific examples thereof include amine-based curing agents, polyaminoamide-based curing agents, acid and acid anhydride-based curing agents, and the like.

The curable composition may contain additives, if necessary, as long as the effects of the present invention are not impaired.
Additives include surfactants, thixotropic agents, defoamers, antioxidants, UV absorbers, light stabilizers, other polymers, oligomers, reactive diluents (monomers), silane coupling agents, fillers. , Solvent and the like.

In the method for producing a curable composition of the present invention described above, a fluoropolymer (A1) is obtained by the above-mentioned method, and a curable composition containing the fluoropolymer (A1) is prepared. Therefore, it is possible to produce a curable composition which is excellent in curability and compatibility of each component without impairing each property as a fluoropolymer.
Since the fluorine-containing polymer (A1) has a large number of hydrocarbon-based crosslinkable groups, it is easily dissolved not only in a solvent having a high fluorine content but also in a solvent having a low fluorine content and a reactive diluent. Therefore, in the curable composition, a wide variety of solvents and reactive diluents can be selected. According to the curable composition in which the fluoropolymer (A1) is dissolved in a solvent or a reactive diluent, it is easy to form a homogeneous coating film by coating. Further, since the fluoropolymer (A1) has a crosslinkable group, the formed coating film has good adhesion to the substrate.

<Fluororesin having a crosslinkable group>
The fluorine-containing polymer having a crosslinkable group according to the embodiment of the present invention is composed of a branched molecular chain having a unit having a fluorine atom, and a fluorine-containing polymer having a crosslinkable group at a plurality of ends of the branched molecular chain (hereinafter, containing). It is also referred to as a fluoropolymer (A2)). It is preferable that at least a part of the unit having a fluorine atom is a unit having a fluorine atom and having an aliphatic ring structure. The crosslinkable group may be present at the end of a part of the branched molecular chain or at all the ends of the branched molecular chain.

Examples of the unit having a fluorine atom include a unit based on the monomer (m1), a unit based on the monomer (m2), and the like.
The unit based on the monomer (m1) also includes a unit (branch point) obtained by removing the iodine atom from the unit based on the monomer (m1), and the iodine atom of the unit based on the monomer (m1) is a crosslinkable group. It is also included that has been converted into a group having. Further, the unit based on the monomer (m2) also includes a unit based on the monomer (m2) in which a group having a crosslinkable group is bonded.

As a unit based on the monomer (m1), an iodine-containing perfluoromonomer can be obtained because the proportion of fluorine atoms in the fluoropolymer (A2) can be increased and the fluoropolymer (A2) having excellent properties as a fluoropolymer can be obtained. Units based on are preferred.

As a unit based on the monomer (m2), it is based on a perfluoromonomer because the proportion of fluorine atoms in the fluoropolymer (A2) can be increased and a fluoropolymer (A2) having excellent properties as a fluoropolymer can be obtained. The unit is preferred.

As a unit based on the monomer (m2), the fluoropolymer (A2) has a fluorine atom because it has excellent solubility in a solvent and a fluoropolymer (A2) having excellent properties as a fluoropolymer can be obtained. However, a unit having an aliphatic ring structure is preferable.

Examples of the unit having a fluorine atom and having an aliphatic ring structure include a unit based on a monomer (m20), a unit based on a monomer (m22), and a unit based on a monomer (m23), and a group (g11) or a group (g11). A unit based on the monomer (m20) or a unit based on the monomer (m23) is preferable from the viewpoint that it can be a unit having g12).
As the unit based on the monomer (m20), a unit based on the monomer (m21) is preferable from the viewpoint of polymerization reactivity and ease of synthesis.

Examples of the unit based on the monomer (m21) include units based on the monomers (m21-1) to (m21-7).

Examples of the unit based on the monomer (m22) include units based on the monomers (m22-1) to (m22-2), and the unit based on the monomer (m22-1) is easy to synthesize. Is preferable.

The unit based on the monomer (m23) is represented by the following formula (u23). Examples of the unit based on the monomer (m23) include units based on the monomers (m23-1) to (m23-3), and the unit based on the monomer (m23-1) is easy to synthesize. Is preferable.
^{R 31 to} R ^{36 in the} unit represented by the formula (u23) are the same as those in the monomer (m23), and the preferred forms are also the same.

The unit based on the monomer (m1) and the unit based on the monomer (m2) are appropriately selected so that the fluoropolymer (A2) has one or both of the group (g11) and the group (g12). Is preferable.
The fluoropolymer (A2) may have a unit based on a third monomer other than the monomer (m1) and the monomer (m2), if necessary, as long as the effect of the present invention is not impaired. Examples of the third monomer include those similar to those in the precursor polymer described above.

The preferable range of the molar ratio (m2 / m1) of the unit based on the monomer (m2) to the unit based on the monomer (m1) in the fluoropolymer (A2) is the same as the preferable range of m2 / m1 in the precursor polymer described above. ..

The fluorine-containing polymer (A2) is obtained, for example, by converting the iodine atom of the precursor polymer having a branched molecular chain into a group having a crosslinkable group among the precursor polymers described above.
As the fluorine-containing polymer (A2), those in which all the iodine atoms of the precursor polymer react with each other and do not contain iodine atoms are preferable, and those having a high conversion rate of iodine atoms to a group having a crosslinkable group are preferable. .. If iodine atoms remain in the fluoropolymer (A2), the fluoropolymer (A2) is easily deteriorated and colored by iodine liberated by light or heat.

The fluorine-containing polymer (A2) is a fluorine-containing polymer having one or both of a group (g11) and a group (g12), that is, the above-mentioned fluorine-containing polymer (A1) from the viewpoint of excellent crosslinkability and solubility. Of these, the one corresponding to the fluorine-containing polymer (A1) having a branched molecular chain is preferable.
Examples of the crosslinkable group include the same as the crosslinkable group in the fluoropolymer (A1) described above, and the preferred form is also the same.

The number of crosslinkable groups per molecule of the fluoropolymer (A2) may be appropriately adjusted according to the balance between the crosslinkability of the fluoropolymer (A2) and each property as the fluoropolymer. If the number of crosslinkable groups per polymer molecule is large, the crosslinkability of the fluoropolymer (A2) is further excellent. Unless the number of crosslinkable groups per polymer molecule is too large, each property as a fluoropolymer is unlikely to be impaired.
As the fluoropolymer (A2), it is preferable that all the units of the fluoropolymer (A2) are units based on the perfluoromonomer or the iodine-containing perfluoromonomer from the viewpoint of being excellent in each property as the fluoropolymer.
The preferable range of the mass average molecular weight of the fluorine-containing polymer (A2) is the same as the preferable range of the mass average molecular weight of the fluorine-containing polymer (A1) described above.

Since the fluoropolymer having a crosslinkable group according to the embodiment of the present invention described above is a polymer having a unit having a fluorine atom, each property (low dielectric constant, low refractive index) as the fluoropolymer. , Transparency, water and oil repellency, heat resistance, light resistance, chemical stability, gas permeability, etc.).
Further, the fluoropolymer having a crosslinkable group according to the embodiment of the present invention described above is a fluoropolymer composed of a branched molecular chain and having a crosslinkable group at a plurality of ends of the branched molecular chain. Therefore, it is excellent in crosslinkability and solubility. That is, when the fluoropolymer (A2) has a branched structure, the crosslinkability is improved and the solubility is also improved. When the fluoropolymer (A2) has many crosslinkable groups, the crosslinkability is improved and the solubility is also improved.

<Curable composition>
The curable composition according to the embodiment of the present invention is a curable composition containing the fluoropolymer (A2) according to the embodiment of the present invention.

The curable composition according to the embodiment of the present invention is the curable composition exemplified in the above-mentioned method for producing a curable composition except that the fluoropolymer (A1) is replaced with the fluoropolymer (A2). The same can be mentioned, and the preferred form is also the same.

Since the curable composition according to the embodiment of the present invention described above contains the fluoropolymer (A2) according to the embodiment of the present invention, each property as the fluoropolymer is not impaired and the curability is not impaired. And excellent compatibility with other components constituting the curable composition.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. Examples 1 to 5 are examples.

(Mole ratio of units)
The molar ratio of each unit in the precursor polymer was determined by elemental analysis and calculated from the iodine content.
The molar ratio of each unit in the fluoropolymer (A1) corresponds to the molar ratio of units in the precursor polymer, and is therefore omitted.

(Mass average molecular weight)
The mass average molecular weight of the precursor polymer or the fluoropolymer (A1) was determined by the method i or the method ii shown below.
Method i:
Using a GPC measuring device (HLC-8320GPC manufactured by Tosoh Corporation), the mass average molecular weight of the polymer in terms of PMMA was determined. As a solvent, Asahiclean AK-225 SEC Grade-1, manufactured by Asahi Glass Co., Ltd. was used. As a column, two PLgel 5μ MIXED-C (manufactured by Polymer Laboratory Co., Ltd.) were connected in parallel and used. The measurement temperature was 40 ° C. As a detector, an evaporation light scattering detector was used.
Method ii:
As a solvent, HFC-52-13p, HCFC-225cc and 1,1,1,3,3,3-hexafluoroisopropyl alcohol were mixed in a volume ratio of 40:55: 5, and the measurement temperature was 37 ° C. The PMMA-equivalent mass average molecular weight of the polymer was determined in the same manner as in Method i, except that it was changed to.

The materials used in the examples are as follows.
(monomer)
PDD: Monomer (m21-1).

BVE: Monomer (m23-1).
_{CF 2 = CF-O-CF} 2 -CF 2 -CF = CF 2 (m23-1)
8IVE:
CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF _2- I

(Radical initiator)
IPP: Diisopropylperoxydicarbonate.
(solvent)
HFC-52-13p: CF ₃ (CF ₂ ) ₅ H,
HCFC-225cc: CClF ₂ CF ₂ CHClF,
AE-3000: CF ₃ CH ₂ OCF ₂ CF ₂ H.
(others)
PHVE-I: CF ₃ CF ₂ CF ₂ OCF (CF ₃ ) CF ₂ OCF ₂ CF _2- I

(Synthesis of 8IVE)
8IVE, Huaxue Xuebao, Vol. 47, No. 7, 1989, p. It was synthesized by the following two-step reaction in the same manner as described in 720-723. The purity by gas chromatography was 99.8% (bp. 62-63 ° C./6.7 kPa).

(Example 1)
Manufacture of precursor polymers:
3.36 g of 8IVE was charged into a Hastelloy autoclave having an internal volume of 120 mL. A solution prepared by dissolving 0.707 g of IPP in about 10 g of HFC-52-13p and 36.24 g of BVE were added, and then HFC was added so that the total amount of HFC-52-13p added in the autoclave was 79.69 g. -52-13p was added. After repeating freeze degassing twice using liquid nitrogen, the temperature was returned to about 0 ° C., and nitrogen gas was introduced to 0.3 MPaG (G indicates a gauge pressure; the same applies hereinafter). The autoclave was set in a water bath, and the mixture was stirred for 7 hours while maintaining the internal temperature at 45 ° C., and then the autoclave was immersed in ice water and cooled to 20 ° C. or lower to stop the reaction.
The reaction was transferred from the autoclave to a beaker and about 33 g of HFC-52-13p was added. About 180 g of n-hexane was added, the mixture was stirred for 30 minutes, and allowed to stand overnight. After decantation, about 125 g of HFC-52-13p was added to dissolve the polymer, and about 180 g of n-hexane was added and stirred for 30 minutes to aggregate the polymer, and then decanted. The same operation was repeated twice more. Vacuum dried at 60 ° C. for 11 days to give 14.2 g of white polymer (p0-1). Table 1 shows the iodine content of the polymer (p0-1) determined by elemental analysis, the molar ratio of BVE-based units to 8IVE-based units (m2 / m1), and the mass average molecular weight determined by method i. The absolute mass average molecular weight of the polymer (p0-1) measured by GPC (hereinafter referred to as “GPC-MALS method”) equipped with a multi-angle light scattering detector is 33,200.
When the polymer (p0-1) was dissolved in HCFC-225cc and ¹⁹ F-NMR was measured, the ratio of the unit based on BVE to which the iodine atom was bound and the unit based on 8IVE in which the iodine atom was not dissociated was-. From the ratio of the peak of 45 to -56 ppm to the peak of around -64 ppm, it was found to be 24:76, and it was confirmed that the polymer (p0-1) was a branched molecular chain.

Production of fluoropolymer (A1):
A solution in which the polymer (p0-1) was dissolved in HCFC-225cc so as to have a concentration of 6% by mass, a solution in which IPP was diluted 400 times by mass ratio with HCFC-225cc, and allyl alcohol was diluted 300 times by mass ratio with HCFC-225ccb. A diluted solution was prepared.
The above solutions are made of Hastelloy with an internal volume of 34 mL in this order so that 1.20 g of the polymer (p0-1) (0.185 mmol as the number of moles of iodine), 10.8 mg of allyl alcohol, and 7.6 mg of IPP. Added to autoclave. Finally, HCFC-225cc was added so that the total amount of HCFC-225cc was 28.78g. After repeating freeze degassing twice using liquid nitrogen, the internal temperature of the autoclave was returned to about 0 ° C., and nitrogen gas was introduced until it reached 0.2 MPaG. The autoclave was set in a water bath and stirred at 45 ° C. for 1 hour, 50 ° C. for 2 hours and 60 ° C. for 2 hours. The autoclave was removed from the water bath and allowed to stand overnight to obtain a reaction solution containing a polymer (p4-1). When about 1 g of the reaction solution was sampled and ¹⁹ F-NMR and ¹ H-NMR were measured, the reaction rate at the iodine terminal was 82.1%, and the conversion rate of the _{iodine terminal to -CH 2} CHICH _{2 OH was.} It was 74.8%.

A mixed solution of 38.2 mg of IPP and 0.600 g of n-hexane and 0.3 g of HCFC-225 kb were added to the reaction solution to seal the autoclave, and then freeze degassing was performed using liquid nitrogen. Repeated times. The internal temperature of the autoclave was returned to about 0 ° C., and nitrogen gas was introduced to 0.3 MPaG. The autoclave was set in a water bath, stirred at 75 ° C. for 7 hours, and then the autoclave was removed from the water bath and allowed to stand overnight. Using HCFC-225 kb as a washing solvent, transfer the reaction solution in the autoclave to an eggplant flask, concentrate with an evaporator until the polymer concentration reaches about 7%, add 20 g of n-hexane to aggregate the polymer, and suction. Filtered. After adding about 10 g of HCFC-225 cc to dissolve the polymer, 20 g of n-hexane was added to aggregate the polymer and filter. After repeating the same operation once again, vacuum drying was performed at 60 ° C. for 3 days. 1.12 g of white polymer (p5-1) was obtained. When the polymer (p5-1) was dissolved in HCFC-225cc and ¹⁹ F-NMR and ¹ H-NMR were measured, the reaction rate of the iodine terminal of the polymer (p0-1) was 100%, and the polymer (p0-1). The conversion rate of the iodine terminal of) to -CH ₂ CH ₂ CH _{2 OH was 47.3%.}

0.349 g of polymer (p5-1), 9.8 mg of acrylate chloride, 10.9 mg of triethylamine and 8.36 g of HCFC-225 kb were added to the glass vessel. As the acrylate chloride and triethylamine, a solution diluted 100-fold by mass ratio with HCFC-225 cc was used. After stirring at room temperature for 3 hours, the mixture was allowed to stand overnight. In order to remove the precipitated solid, filtration was performed using a syringe equipped with a filter having a pore size of 0.45μ. The filtrate was colorless and transparent. After concentration with an evaporator until the polymer concentration reached about 7% by weight, about 6 g of hexane was added to aggregate the polymer. After suction filtration, the polymer was dissolved in HCFC-225cc, the insoluble matter was filtered in the same manner as before, and then the polymer was aggregated with about 6 g of hexane and suction filtration was performed. The same operation was repeated once again. The obtained polymer was dissolved in perfluorobenzene and the insoluble matter was removed with a syringe equipped with a filter in the same manner as described above. The solvent was distilled off using an evaporator, and perfluorobenzene was added to replace the solvent to obtain 4.69 g of a solution containing the polymer (p6-1). After washing this solution with the same volume of water, when the lower layer was ^{measured by 1} H-NMR, -CH ₂ CH ₂ CH ₂ OH was quantitatively converted to -CH ₂ CH ₂ CH ₂ OCOCH = CH _2. rice field.

(Example 2)
Production of fluoropolymer (A1):
A solution obtained by dissolving the polymer (p0-1) obtained in Example 1 in HCFC-225 kb at a concentration of 7.7 mass%, a solution in which allyl alcohol was diluted 100 times by mass ratio with HCFC-225 cc, and IPP with HCFC-225 cc. A solution diluted 200 times by mass was prepared.
The above solutions are made of Hastelloy with an internal volume of 120 mL in this order so that the amount of the polymer (p0-1) is 6.29 g (0.952 mmol as the number of moles of iodine), 66.3 mg of allyl alcohol, and 39.3 mg of IPP. Added to autoclave. Finally, HCFC-225cc was added so that the total amount of HCFC-225cc was 103.60g. After repeating freeze degassing twice using liquid nitrogen, the temperature was returned to about 0 ° C., and nitrogen gas was introduced until the temperature reached 0.2 MPaG. The autoclave was set in a water bath and stirred at 45 ° C. for 1 hour, 50 ° C. for 2 hours and 60 ° C. for 2 hours. The autoclave was removed from the water bath and allowed to stand overnight to obtain a reaction solution containing a polymer (p4-2). When about 1 g of the reaction solution was sampled and ¹⁹ F-NMR and ¹ H-NMR were measured, the reaction rate at the iodine terminal was 80.6%, and the conversion rate of the _{iodine terminal to -CH 2} CHICH _{2 OH was.} It was 80.2%.
Using HCFC-225cc as a washing solvent, the reaction solution in the autoclave was transferred to an eggplant flask. The amount of liquid in the flask was 123 g. 150 g of hexane was added and stirred to agglomerate the polymer and suction filtered. About 100 g of HCFC-225 cc was added to the obtained polymer to dissolve it, and the polymer was aggregated with about 150 g of hexane and suction filtered. This operation was repeated once more. Vacuum dried at 60 ° C. for 58 hours to give 5.95 g of white polymer (p4-2).

A solution in which IPP was diluted 500-fold by mass ratio with HCFC-225 cc and a solution in which Bu ₃ SnH was diluted 2-fold by mass ratio with HCFC-225 cc were prepared.
To a 100 mL four-necked flask equipped with a stirrer, a Dimroth condenser and a thermometer, 5.15 g of the polymer (p4-2) and 61.54 g of the HCFC-225 kb were added and stirred to dissolve the polymer. Then, the above solution was added so as to be _{0.161 g of IPP and 3.40 g of Bu 3 SnH.} Next, HCFC-225cc was added to bring the total amount of HCFC-225cc to 81.44 g. After sealing the flask, freezing and degassing was repeated twice using liquid nitrogen. After degassing, when the internal temperature of the flask was returned to room temperature in a water bath, nitrogen gas was introduced to return the inside of the flask to normal pressure. The flask was set in a water bath and stirred at 50 ° C. for 2 hours under a nitrogen atmosphere. The flask was removed from the water bath and cooled to room temperature.
HCFC-225 kb was used as a washing solvent, and the reaction solution in the flask was transferred to a beaker. The amount of liquid in the beaker was 105 g. About 130 g of hexane was added and stirred to agglomerate the polymer and suction filtered. The obtained polymer was dissolved in about 100 g of HCFC-225 cc, the polymer was aggregated with about 130 g of hexane, and suction filtration was performed. The operations of dissolving, aggregating, and filtering the polymer were repeated once more. Vacuum dried at 60 ° C. for 12 hours to give 4.62 g of white polymer (p5-2). When the polymer (p5-2) was dissolved in HCFC-225cc and ¹⁹ F-NMR and ¹ H-NMR were measured, the reaction rate of the iodine terminal of the polymer (p0-1) was 100%, and the polymer (p4-2). The reaction rate of -CHI- in) was also 100%, and _{the conversion rate of the polymer (p0-1) from the iodine terminal to -CH 2} CH ₂ CH ₂ OH was 72.4%.

A solution of acrylate chloride diluted 80 times by mass ratio with HCFC-225 cc, a solution of triethylamine diluted 80 times by mass ratio with HCFC-225 cc, and a solution of 4-methoxyphenol diluted 800 times by mass ratio with HCFC-225 cc. Prepared.
0.450 g of polymer (p5-2) and 6.49 g of HCFC-225 cc were added to a glass container having an internal volume of 30 mL, and the mixture was stirred and dissolved. Next, 0.135 g of the 4-methoxyphenol solution, 1.97 g of the acrylic acid chloride solution, and triethylamine so that 4-methoxyphenol, acrylate chloride, and triethylamine are 0.0014 mmol, 0.272 mmol, and 0.272 mmol, respectively. 2.21 g of the solution was added in this order. After stirring at room temperature for 3 hours, the mixture was allowed to stand overnight. The precipitated solid content was removed by filtering with a filter having a pore size of 0.45 μm. From the obtained filtrate, the solvent was distilled off with an evaporator without heating to obtain a polymer. 10 g of a mixed solvent of methanol / water (mass ratio 9/1) was added to the polymer and stirred, and the polymer was washed and suction filtered. After repeating the same operation twice, the mixture was washed with 10 g of methanol and filtered. The obtained polymer was vacuum dried at room temperature to obtain a polymer (p6-2). ^{When 1} H-NMR was measured by dissolving in perfluorobenzene so that the polymer concentration was 7% by mass _{, -CH 2} CH ₂ CH ₂ OH was almost quantitatively changed to -CH ₂ CH ₂ CH ₂ OCOCH = CH ₂ . It was confirmed that it was converted.

(Example 3)
Production of fluoropolymer (A1):
A solution of the polymer (p0-1) obtained in Example 1 dissolved in HCFC-225 cc at a concentration of 6% by mass, a solution of IPP diluted 400 times by mass ratio with HCFC-225 cc, and dimethoxymethylvinylsilane with HCFC-225 cc. A solution diluted 50 times by mass was prepared.
Hastelloy with an internal volume of 34 mL was added in this order so that 1.20 g of the polymer (p0-1) (0.185 mmol as the number of moles of iodine), 7.6 mg of IPP, and 49.0 mg of dimethoxymethylvinylsilane were obtained. Added to autoclave made. Finally, HCFC-225cc was added so that the total amount of HCFC-225cc was 28.74g. After repeating freezing and degassing twice using liquid nitrogen, the internal temperature of the autoclave was returned to about 0 ° C., and nitrogen gas was introduced until it reached 0.2 MPaG. The autoclave was set in a water bath and stirred at 50 ° C. for 2 hours, 60 ° C. for 2 hours and 70 ° C. for 2 hours. The autoclave was removed from the water bath and allowed to stand overnight to obtain a reaction solution containing a polymer (p11-1). When about 1 g of the reaction solution was sampled and ¹⁹ F-NMR and ¹ H-NMR were measured, the reaction rate at the iodine terminal was 100%, and the reaction rate at the iodine terminal was changed to −CH ₂ CHISiCH ₃ (OCH ₃ ) _{2 at the} iodine terminal. The conversion rate was 80.5%, and the conversion rate of the iodine terminal to −CH ₂ CH ₂ SiCH ₃ (OCH ₃ ) ₂ was 15.5%.

To the reaction solution, 19.1 mg of IPP and 0.300 g of n-hexane and 0.3 g of HCFC-225 kb were added to seal the autoclave, and then freeze degassing was performed using liquid nitrogen. Repeated times. The internal temperature of the autoclave was returned to about 0 ° C., and nitrogen gas was introduced to 0.3 MPaG. The autoclave was set in a water bath, stirred at 75 ° C. for 7 hours, and then the autoclave was removed from the water bath and allowed to stand overnight. When about 1 g of the obtained reaction solution was sampled and ¹⁹ F-NMR and ¹ H-NMR were measured, it was confirmed that the peak of -CHI- was almost eliminated. Using HCFC-225cc as a washing solvent, the reaction solution in the autoclave was transferred to an eggplant flask and concentrated by an evaporator. The amount of liquid after concentration was 17 g. About 50 g of AE-3000 was added, aggregated, and suction filtered. The obtained polymer was dissolved in about 15 g of HCFC-225 cc, about 50 g of AE-3000 was added to aggregate the polymer, and suction filtration was performed. The obtained polymer was dissolved in about 15 g of HCFC-225 cc to obtain a solution of the polymer (p12-1) having _{−CH 2} CH ₂ SiCH ₃ (OCH ₃ ) _{2 at the end.}

(Example 4)
Manufacture of precursor polymers:
To a stainless steel autoclave having an internal volume of 110 mL, 2.98 g of 8IVE, about 5 g of 0.126 g of IPP dissolved in HCFC-225 kb, and 13.37 g of PDD were added, and finally HCFC-225 cc was added. The total amount of HCFC-225cc added was 61.78g. After repeating freeze degassing twice using liquid nitrogen, the temperature was returned to about 0 ° C., and nitrogen gas was introduced to 0.3 MPaG. The autoclave was set in a water bath, and the mixture was stirred for 8 hours while maintaining the internal temperature at 45 ° C., and then the autoclave was immersed in ice water and cooled to 20 ° C. or lower to stop the reaction.
The jelly-like product was transferred from the autoclave to the beaker and HCFC-225 kb was added to bring the total volume to 128 g. After stirring with a magnetic stirrer for 30 minutes, 150 g of n-hexane was added to aggregate the polymer, followed by stirring for 30 minutes. After filtration under reduced pressure, the obtained polymer was washed with n-hexane. The washed polymer was returned to the beaker, HCFC-225 kb was added until the total amount was 128 g, and the mixture was stirred for 30 minutes. 150 g of n-hexane was added and stirred for 30 minutes to allow the polymer to aggregate. The polymer obtained by suction filtration was washed with n-hexane, and then the same operation was repeated again. Then, it was vacuum dried at 60 degreeC until it became constant, and 12.4 g of a white powder polymer (p0-2) was obtained. Table 1 shows the iodine content of the polymer (p0-2) determined by elemental analysis, the molar ratio of PDD-based units to 8IVE-based units (m2 / m1), and PMMA-equivalent mass average molecular weight determined by method ii. .. The absolute mass average molecular weight of the polymer (p0-2) by the GPC-MALS method is 64,100.
When the polymer (p0-2) was dissolved in perfluorobenzene ^{and measured by 19} F-NMR, it was found that there was a PDD-based unit to which an iodine atom was bonded, and the polymer (p0-2) was a branched molecular chain. It was confirmed that. The ratio of the unit based on PDD to which the iodine atom is bound and the unit based on 8IVE in which the iodine atom is not dissociated is 42 to -47 ppm of ¹⁹ F-NMR (the chemical shift of perfluorobenzene is set to -162.7 ppm). From the ratio of the peak of the above to the peak around -62 ppm, it was found to be 50:50.

Production of fluoropolymer (A1):
A solution in which the polymer (p0-2) was dissolved in HCFC-225 cc so as to be 4% by mass, a solution in which PHVE-I was diluted 10 times by mass ratio with HCFC-225 cc, and IPP was diluted 100 times by mass ratio with HCFC-225 cc. A diluted solution and a solution obtained by diluting allyl alcohol with HCFC-225 cc at a mass ratio of 100 times were prepared.
The above solutions were added in this order so as to be 2.40 g of the polymer (p0-2) (0.415 mmol as the number of moles of iodine), 72.4 mg of allyl alcohol, 42.8 mg of IPP, and 360 mg of PHVE-I. It was added to a Hastelloy autoclave having an internal volume of 120 mL. Finally, HCFC-225cc was added so that the total amount of HCFC-225cc was 117.13g. After repeating freeze degassing twice using liquid nitrogen, the temperature was returned to about 0 ° C., and nitrogen gas was introduced to 0.2 MPaG. The autoclave was set in a water bath and stirred at 50 ° C. for 2 hours, 60 ° C. for 2 hours and 70 ° C. for 1 hour.
Using HCFC-225cc as a washing solvent, the reaction solution of the autoclave was transferred to an eggplant flask. The amount of liquid in the flask was 133 g. 166 g of hexane was added and stirred to agglomerate the polymer and suction filtered. About 120 g of HCFC-225 cc was added to the obtained polymer to dissolve it, and about 170 g of hexane was added to aggregate the polymer and suction filtration was performed. The same operation was repeated once again. Vacuum drying was performed at 60 ° C. for 3 days to obtain 2.23 g of a white polymer (p4-3) containing a _{trace amount of CF 3} CF ₂ CF ₂ OCF (CF ₃ ) CF ₂ CH ₂ CHICH _{2 OH.} When the polymer (p4-3) was dissolved in HCFC-225cc and ¹⁹ F-NMR and ^{1 1} H-NMR were measured, the reaction rate of the terminal iodine was 82.6%, and the terminal iodine -CH ₂ CHICH ₂ OH. The conversion rate to was 73.7%. The product contained 4.1 parts by mass of _{CF 3} CF ₂ CF ₂ OCF (CF ₃ ) CF ₂ CH ₂ CHICH ₂ OH with respect to 100 parts by mass of the polymer (p4-3). ..

A solution in which IPP was diluted 200-fold by mass ratio with HCFC-225 cc and a solution in which Bu ₃ SnH was diluted 1.5-fold by mass ratio with HCFC-225 cc were prepared.
To a 50 mL four-necked flask equipped with a stirrer, a Dimroth condenser and a thermometer, 1.00 g of the polymer (p4-3) and 22.15 g of the HCFC-225 kb were added and stirred to dissolve the polymer. Then, the above solution was added so as to be 3.6 mg of IPP _{and 757 mg of Bu 3 SnH.} Then HCFC-225cc was added. The total amount of HCFC-225cc was 23.24g. After sealing the flask, freezing and degassing was repeated twice using liquid nitrogen. After degassing, when the internal temperature of the flask was returned to room temperature in a water bath, nitrogen gas was introduced to return the inside of the flask to normal pressure. The flask was set in a water bath and stirred at 50 ° C. for 2 hours under a nitrogen atmosphere. The flask was removed from the water bath and cooled to room temperature.
HCFC-225 kb was used as a washing solvent, and the reaction solution in the flask was transferred to a beaker. The amount of liquid in the beaker was 36.2 g. About 45 g of hexane was added and stirred to agglomerate the polymer and suction filtered. The obtained polymer was dissolved in about 33 g of HCFC-225 cc, the polymer was aggregated with about 45 g of hexane, and suction filtration was performed. The operations of dissolving, aggregating, and filtering the polymer were repeated once more. Vacuum dried at 60 ° C. for 21 hours to give 0.84 g of white polymer (p5-3). When the polymer (p5-3) was dissolved in HCFC-225cc and ¹⁹ F-NMR and ¹ H-NMR were measured, the reaction rate of the iodine terminal of the polymer (p0-2) was 100%, and the polymer (p4-). The reaction rate of -CHI- in 3) was 86.9%, and _{the conversion rate of the polymer (p0-2) from the iodine terminal to -CH 2} CH ₂ CH ₂ OH was 63.9%.

A solution of acrylate chloride diluted 40 times by mass ratio with HCFC-225 cc, a solution of triethylamine diluted 40 times by mass ratio with HCFC-225 cc, and a solution of 4-methoxyphenol diluted 800 times by mass ratio with HCFC-225 cc. Prepared.
0.20 g of polymer (p5-3) and 3.67 g of HCFC-225 cc were added to a glass container, and the mixture was stirred and dissolved. Next, 0.069 g of the 4-methoxyphenol solution, 0.502 g of the acrylic acid chloride solution, and triethylamine so that 4-methoxyphenol, acrylate chloride, and triethylamine are 0.0007 mmol, 0.139 mmol, and 0.139 mmol, respectively. 0.561 g of the solution was added in this order. After stirring at room temperature for 3 hours, the mixture was allowed to stand overnight. The precipitated solid content was removed by filtering with a filter having a pore size of 5 μm. To the obtained filtrate, the same volume of water as the filtrate was added, washed twice, and the lower layer was dried over magnesium sulfate. Magnesium sulfate was filtered off to give a solution containing the polymer (p6-3). It was measured ¹ _H-NMR, the conversion of the -CH _{2 CH 2} CH ₂ OH to _{-CH 2 CH 2 CH 2 OCOCH =} CH 2 was 87.7%.

(Example 5)
Manufacture of precursor polymers:
A polymer (p0-2) was obtained in the same manner as in Example 4.

Production of fluoropolymer (A1):
The amount charged into the autoclave was the same as in Example 4 except that the total amount of polymer (p0-2) was changed to 3.59 g, allyl alcohol was 78.4 mg, PHVE-I was 240 mg, and HCFC-225 kb was changed to 116.05 g. CF ₃ CF ₂ CF ₂ OCF (CF ₃ ) CF ₂ CH ₂ CHICH ₂ OH-containing polymer (p4-4) was obtained. When the polymer (p4-4) was dissolved in HCFC-225cc and ¹⁹ F-NMR and ^{1 1} H-NMR were measured, the reaction rate of the terminal iodine was 84%, and the reaction rate of the terminal iodine to -CH ₂ CHICH ₂ OH was found. The conversion rate was 78%. The product contained 2.1 parts by mass of _{CF 3} CF ₂ CF ₂ OCF (CF ₃ ) CF ₂ CH ₂ CHICH ₂ OH with respect to 100 parts by mass of the polymer (p4-4). ..

A solution in which IPP was diluted 100-fold by mass ratio with HCFC-225 cc and a solution in which Bu ₃ SnH was diluted 2-fold by mass ratio with HCFC-225 cc were prepared.
2.86 g of polymer (p4-4) and 60.91 g of HCFC-225 kb were added to a 50 mL four-necked flask equipped with a stirrer, a Dimroth condenser and a thermometer, and the mixture was stirred to dissolve the polymer. Then, the above solution was added so as to be 11.9 mg of _{IPP and 2.52 g of Bu 3 SnH.} Then HCFC-225cc was added. The total amount of HCFC-225cc was 64.61g. After that, 2.69 g of the white polymer (p5-4) was obtained in the same manner as in Example 4. The reaction rate of the iodine terminal of the polymer (p0-2) is 100%, the reaction rate of -CHI- of the polymer (p4-4) is also 100%, and -CH ₂ CH from the iodine terminal of the polymer (p0-3). _{The conversion rate to 2} CH ₂ OH was 77%.

A solution of acrylate chloride diluted 10 times by mass ratio with HCFC-225 cc, a solution of triethylamine diluted 10 times by mass ratio with HCFC-225 cc, and a solution of 4-methoxyphenol diluted 500 times by mass ratio with HCFC-225 cc. Prepared.
2.40 g of polymer (p5-4) and 53.38 g of HCFC-225 kb were added to a glass container, and the mixture was stirred and dissolved. Next, 1.03 g of 4-methoxyphenol solution, 1.51 g of acrylic acid chloride solution, and triethylamine so that 4-methoxyphenol, acrylate chloride, and triethylamine are 0.0166 mmol, 1.66 mmol, and 1.66 mmol, respectively. 1.68 g of the solution was added in this order. Stir overnight at room temperature. It aggregated with 102 g of methanol, stirred for 30 minutes, and then filtered under reduced pressure. To the obtained filtrate, 0.5 g of a solution obtained by diluting the above 4-methoxyphenol with HCFC-225 kb in a mass ratio of 500 times and HCFC-225 cc were added to bring the total amount to 69 g. After stirring for 30 minutes, the polymer was reaggregated with 102 g of methanol, stirred for 30 minutes and then filtered under reduced pressure. Further, the same operation as described above was carried out, and the mixture was aggregated with methanol and filtered under reduced pressure to obtain a solid content. To the obtained solid content, 0.5 g of a solution obtained by diluting the above 4-methoxyphenol with HCFC-225 cc in a mass ratio of 500 times and HCFC-225 cc were added to make the total amount 69 g, and the mixture was stirred for 30 minutes. Then, 84 g of hexane was added, the polymer was agglomerated, stirred for 30 minutes, and filtered under reduced pressure. After repeating this dissolution / aggregation / filtration operation twice more, the mixture was vacuum dried overnight at room temperature to obtain 2.17 g of the polymer (p6-4). ^{From 19} F-NMR and ^{1 1} H-NMR analysis, the conversion rate of the iodine terminal of the polymer (p0-3) to -CH ₂ CH ₂ CH ₂ OCOCH = CH ₂ was 71%, and triethylamine hydrochloride was removed. I confirmed that it was done.

(Evaluation of photocurability and liquid repellency)
0.1 g of polymer (p6-4) and 0.9 g of perfluorobenzene were placed in a 6 mL glass vial and stirred well to give a uniform solution. The obtained solution was filtered through a polytetrafluoroethylene filter having a pore size of 0.20 μm to prepare a resin composition. The photocurability and liquid repellency were evaluated using the above resin composition.

Photocurability:
The resin composition was spin-coated on a slide glass (Matsunami Glass Co., Ltd., S9111) substrate at 1,000 rpm for 30 seconds, and heated at 100 ° C. for 120 seconds using a hot plate to form a dry coating film. .. A high-pressure mercury lamp was used as a light source, and the mixture was exposed for 2 minutes at an illuminance of ^{100 mW / cm 2 in a nitrogen atmosphere.}
When the dry coating film before exposure and the coating film after exposure were immersed in AK-225 (manufactured by Asahi Glass Co., Ltd.) for 1 minute, the dry coating film before exposure was dissolved, while the coating film after exposure was dissolved. There wasn't. From this, it was confirmed that a cured film was obtained by exposure.

Liquid repellency:
The substrate on which the dry coating film before exposure was formed and the substrate on which the coating film after exposure was formed were immersed in AK-225, respectively. The dry coating before exposure was dissolved in AK-225. Next, on each substrate, the contact angle of water in the portion where the coating film was formed or the coating film was measured with a fully automatic contact angle meter (DM-701, manufactured by Kyowa Interface Science Co., Ltd.). The contact angle in the portion where the dry coating film was formed before the exposure was 4 °, and the contact angle in the coating film on the substrate obtained by immersing the substrate on which the coating film was formed after the exposure was AK-225 was It was 113 °.

The fluoropolymer in the present invention has good crosslinkability because a crosslinkable group is introduced at the end of the molecular chain. The curable composition containing the fluoropolymer exhibits photocurability by adding a photoacid generator or a photopolymerization initiator as necessary, and fine patterning is possible, so that it is a raw material in the electronic field. It is useful as. Further, since the cured product of the fluoropolymer has a low dielectric constant, a low refractive index, and excellent transparency, water and oil repellency, heat resistance, gas permeability, etc., electronic members (printed substrates, etc.), optical members, etc. It can be used for (optical waveguides, lenses, antireflection films, etc.), water and oil repellent imparting agents, mold release agents, biochips, and the like.

Claims (8)

Includes an iodine-containing perfluoromonomer and a monomer having a fluorine atom and no iodine atom, which is one or both of a monomer represented by the formula (m21) and a monomer represented by the formula (m23). The monomer component is polymerized to obtain a precursor polymer having either or both of the group represented by the following formula (g1) and the group represented by the following formula (g2), and the precursor polymer in the following formula is used. A method for producing a fluoropolymer composed of a branched molecular chain having a crosslinkable group, which converts an iodine atom into a group having a crosslinkable group.

R ¹¹ and R ¹² are independently fluorine atoms or perfluoroalkyl groups having 1 to 5 carbon atoms. R ¹³ and R ¹⁴ are independently a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkoxy group having 1 to 5 carbon atoms.
CF (R ³¹ ) = C (R ³³ ) -O-CF (R ³⁶ ) -CF (R ³⁵ ) -C (R ³⁴ ) = CF (R ³² ) (m23)
R ^{31 to} R ³⁶ are monovalent perfluoroorganic groups or fluorine atoms which may independently have an ether-bonding oxygen atom.

However, R ¹ is a monovalent perfluoroorganic group or a fluorine atom which may have an ether-bonding oxygen atom, and R ² and R ³ are independently a fluorine atom and a perfluoro having 1 to 5 carbon atoms, respectively. an alkyl group or perfluoroalkoxy group having 1 to 5 carbon atoms, R ⁴ constitutes a part of some or 6-membered ring of 5-membered ring, straight chain which may contain an etheric oxygen atom Alternatively, it is a branched perfluoroalkylene group. The first aspect of claim 1, wherein the crosslinkable group is at least one selected from the group consisting of a group represented by the following formula (g3), an epoxy group, a vinyl group and a group represented by the following formula (g4). A method for producing a fluoropolymer having a crosslinkable group.
-OCOCX ¹ = CH ₂ (g3)
−SiX ² _n (OR ⁵ ) _3-n (g4)
However, X ¹ is a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 4 carbon atoms or a perfluoroalkyl group having 1 to 4 carbon atoms, and X ² is an alkyl group having 1 to 4 carbon atoms. , N is an integer of 0 to 2, and R ⁵ is an alkyl group having 1 to 4 carbon atoms. The method for producing a fluoropolymer having a crosslinkable group according to any one of claims 1 or 2 , wherein the fluoropolymer having a crosslinkable group has a mass average molecular weight of 5,000 to 80,000. A fluoropolymer having a crosslinkable group is obtained by the method for producing a fluoropolymer having a crosslinkable group according to any one of claims 1 to 3, and a curable composition containing the fluoropolymer is prepared. , A method for producing a curable composition. A branched molecular chain having a monomer represented by the formula (m21) as a unit having a fluorine atom, a unit based on one or both of the monomers represented by the formula (m23), and a unit based on an iodine-containing perfluoromonomer. A curable composition comprising a fluoropolymer having a crosslinkable group and having a crosslinkable group at a plurality of ends of the branched molecular chain.

R ¹¹ and R ¹² are independently fluorine atoms or perfluoroalkyl groups having 1 to 5 carbon atoms. R ¹³ and R ¹⁴ are independently a fluorine atom, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkoxy group having 1 to 5 carbon atoms.
CF (R ³¹ ) = C (R ³³ ) -O-CF (R ³⁶ ) -CF (R ³⁵ ) -C (R ³⁴ ) = CF (R ³² ) (m23)
R ^{31 to} R ³⁶ are monovalent perfluoroorganic groups or fluorine atoms which may independently have an ether-bonding oxygen atom. A curable composition comprising a fluoropolymer having a crosslinkable group according to claim 5 , which has one or both of a group represented by the following formula (g11) and a group represented by the following formula (g12). Things .

However, R ¹ is a monovalent perfluoroorganic group or a fluorine atom which may have an ether-bonding oxygen atom, and R ² and R ³ are independently a fluorine atom and a perfluoro having 1 to 5 carbon atoms, respectively. an alkyl group or perfluoroalkoxy group having 1 to 5 carbon atoms, R ⁴ constitutes a part of some or 6-membered ring of 5-membered ring, straight chain which may contain an etheric oxygen atom Alternatively, it is a branched perfluoroalkylene group, and A is a group having a crosslinkable group. The crosslinkable group is at least one selected from the group consisting of a group represented by the following formula (g3), an epoxy group, a vinyl group and a group represented by the following formula (g4), claim 5 or 6. A curable composition comprising a fluoropolymer having a crosslinkable group according to any one of the above items.
-OCOCX ¹ = CH ₂ (g3)
−SiX ² _n (OR ⁵ ) _3-n (g4)
However, X ¹ is a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 4 carbon atoms or a perfluoroalkyl group having 1 to 4 carbon atoms, and X ² is an alkyl group having 1 to 4 carbon atoms. , N is an integer of 0 to 2, and R ⁵ is an alkyl group having 1 to 4 carbon atoms. A curable composition comprising a fluoropolymer having a crosslinkable group according to any one of claims 5 to 7 , which has a mass average molecular weight of 5,000 to 80,000.