JP2011195626A - Solvent-free transparent curable fluororesin composition - Google Patents

Abstract

A solvent-free transparent curable fluorine-containing resin composition that does not cause yellowing or the like upon heating is provided.
Unsaturation obtained by subjecting a hydroxyl group-containing fluoropolymer containing a hydroxyl group-containing structural unit (1) having an ether type side chain and (b) an unsaturated carboxylic acid or an acid halide thereof to an esterification reaction. A heat-resistant transparent solventless curable fluorine-containing resin composition in which a group-containing fluorine-containing polymer (I) is dissolved in an acrylic monomer (II).
[Selection] Figure 3

Description

  The present invention relates to a solventless transparent curable fluorine-containing resin composition that does not cause yellowing during heating.

  Conventionally, as a curable resin composition using a fluorine-containing polymer, a curable fluorine-containing heavy polymer bonded to a polymer main chain with an ester bond having a fluorine-containing acryloyl group containing an ethylenic carbon-carbon double bond in a side chain. It has been proposed that a solvent-type composition in which a coalescence is used and dissolved in an organic solvent is useful as an antireflection film material (Patent Document 1).

  In Patent Document 2, an unsaturated group-containing fluorine-containing polymer obtained by esterifying a hydroxyl group-containing fluorine-containing copolymer and a non-fluorinated α, β-unsaturated carboxylic acid or derivative thereof is used. However, it is finally graft-polymerized with an acrylic monomer in an organic solvent.

  In contrast to this solvent-type curable fluorine-containing resin composition, solvent-free curable fluorine-containing resin compositions that do not use a solvent have also been proposed (Patent Documents 3, 4, 5, and 6).

  The curable fluorinated polymer used in the solvent-free curable fluorinated resin composition described in Patent Documents 3, 4 and 5 is (A) a radical polymerizable unsaturated monomer containing a fluorine atom and a hydroxyl group. Reaction of hydroxyl group-containing fluoropolymer (A-1) containing a monomer unit with an isocyanate group-containing unsaturated compound (A-2) having one isocyanate group and at least one radical polymerizable unsaturated group The product is a product in which a side chain having an ethylenic carbon-carbon double bond is bonded to a polymer main chain by a urethane bond.

  Patent Document 6 discloses an unsaturated group-containing fluorine-containing polymer obtained by reacting a hydroxyl group-containing fluorine-containing copolymer with a non-fluorinated α, β-unsaturated carboxylic acid or derivative thereof as an acrylic monomer. An active energy ray-curable composition obtained by diluting with a reactive diluent such as is disclosed.

International Publication No. 02/18457 Pamphlet Japanese Patent Publication No.59-46964 JP-A-62-25104 International Publication No. 2008/093776 Pamphlet International Publication No. 2008/099782 Pamphlet JP-A-64-51418

  In the curable fluoropolymers described in Patent Documents 3, 4 and 5, the side chain having an ethylenic carbon-carbon double bond is bonded to the polymer main chain with a urethane bond, so that the heat resistance Improvement in terms of (yellowing, etc.) is required.

  The hydroxyl group-containing fluorine-containing copolymer used in the active energy ray-curable composition described in Patent Document 6 is a fluoroolefin unit such as tetrafluoroethylene or chlorotrifluoroethylene as the fluorine-containing structural unit. There is no hydroxyl group in the structural unit. The hydroxyl group is contained in a hydrocarbon monomer unit copolymerizable with such a fluoroolefin unit. For this reason, when trying to increase the number of hydroxyl groups, the fluorine content inevitably decreases, and there is a problem that the original characteristics of the fluororesin are impaired. Further, in the case of a small amount of hydroxyl groups, the original purpose, that is, the crosslinking points in the crosslinked structure are reduced, and the physical properties are impaired. Further, fluoroolefin units such as tetrafluoroethylene and chlorotrifluoroethylene as the fluorine-containing structural unit are desired to be further improved in that they are very poor in compatibility with acrylic and easily lose transparency.

  An object of the present invention is to provide a solvent-free transparent curable fluorine-containing resin composition that does not cause yellowing during heating.

The present invention
(A) Formula (1):
Wherein X ¹ and X ² are the same or different and are a fluorine atom or a hydrogen atom; X ³ is a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or a trifluoromethyl group; X ⁴ and X ⁵ are the same or Differently, a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; a is an integer of 1 to 3; R ¹ is a linear or branched alkyl group containing at least one hydroxyl group, a fluoroalkyl group, a peroxy group; A hydroxyl group-containing fluoropolymer comprising a hydroxyl group-containing structural unit (1) represented by a fluoroalkyl group (which may contain an ether bond and / or an ester bond in the chain);
(B) A heat resistant transparent solution in which an unsaturated group-containing fluoropolymer (I) obtained by subjecting an unsaturated carboxylic acid or its acid halide to an esterification reaction is dissolved in an acrylic monomer (II) The present invention relates to a solvent-free curable fluorine-containing resin composition.

As the hydroxyl group-containing fluoropolymer (a), the formula (1a):
(Wherein Z is a hydrocarbon group containing at least one monovalent carbon-carbon double bond, Y is a divalent organic group or a single bond; m is an integer of 0 to 5). It preferably contains an ether structural unit.

Moreover, as unsaturated carboxylic acid (b), Formula (4):
^{CX 11 X 12 = CX 13 -} (R 3) c -COM
Wherein X ¹¹ and X ¹² are the same or different and are a fluorine atom or a hydrogen atom; X ¹³ is a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or a trifluoromethyl group; M is —OH or a halogen atom; ³ is preferably a compound represented by a divalent organic group; c is 0 or 1).

  The present invention also provides a fluorine-containing polymer (a) containing the hydroxyl group-containing structural unit (1) represented by the formula (1) and further the formula (1a), an unsaturated carboxylic acid or an acid halide (b) thereof. Furthermore, after the esterification reaction with the unsaturated carboxylic acid represented by the formula (4) or its acid halide, impurities are removed by purification, and the unsaturated group is obtained by drying under conditions of 60 ° C. or less. The present invention also relates to a method for producing the heat-resistant transparent solventless curable fluorine-containing resin composition of the present invention, wherein the fluorine-containing polymer (I) is dissolved in an acrylic monomer (II).

  The present invention also relates to a cured product obtained by curing the curable fluorinated resin composition of the present invention.

  According to the present invention, it is possible to provide a solventless transparent curable fluorine-containing resin composition that does not cause yellowing during heating.

4 is a graph showing the influence of temperature on the polymer measured in Reference Example 1. It is a graph of the light transmittance of the cured film used for the high temperature holding test in Example 12. It is a photograph of the cured film before and after the high temperature holding test in Example 12. 6 is a graph of light transmittance of a cured film subjected to a high temperature holding test in Comparative Example 3. It is a photograph of the cured film before and after the high temperature holding test in Comparative Example 3. It is a graph of the light transmittance of the cured film which used for the high temperature long-term holding test in Example 13. It is a graph of the light transmittance of the cured film which used for the high temperature long-term holding test in the comparative example 4.

The heat-resistant transparent solventless curable fluorine-containing resin composition of the present invention is
A hydroxyl group-containing fluoropolymer containing a hydroxyl group-containing structural unit (1) represented by the formula (1);
(B) The unsaturated group-containing fluoropolymer (I) obtained by subjecting the unsaturated carboxylic acid or its acid halide to an esterification reaction is dissolved in the acrylic monomer (II).

  Hereinafter, each component will be described.

(I) Unsaturated group-containing fluorinated polymer The unsaturated group-containing fluorinated polymer (I) is composed of the hydroxyl group-containing fluorinated polymer (a) represented by the formula (1) and an unsaturated carboxylic acid or an acid halide thereof. It is obtained by subjecting (b) to an esterification reaction.

(A) Hydroxyl group-containing fluoropolymer The hydroxyl group-containing fluoropolymer (a) has the formula (1):
Wherein X ¹ and X ² are the same or different and are a fluorine atom or a hydrogen atom; X ³ is a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or a trifluoromethyl group; X ⁴ and X ⁵ are the same or Differently, a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; a is an integer of 1 to 3; R ¹ is a linear or branched alkyl group containing at least one hydroxyl group, a fluoroalkyl group, a peroxy group; A hydroxyl group-containing fluoropolymer (a) comprising a hydroxyl group-containing structural unit (1) represented by a fluoroalkyl group (which may contain an ether bond and / or an ester bond in the chain) is an acrylic group It is used from the viewpoint of high compatibility with the monomer (II) and high fluorine content.

In addition, a hydroxyl group-containing fluorine-containing structural unit containing at least one fluorine atom in any of X ^{1 to} X ⁵ and R ¹ is preferable in terms of high esterification reactivity, and X ¹ and X ² are each hydrogen. From the viewpoint of the monomer, from the viewpoint of the polymer skeleton, X ³ is a fluorine atom, a = 1, and X ⁴ and X ⁵ are fluorine atoms. It is preferable in terms of high compatibility with the acrylic monomer (II) and high fluorine content.

Next, the hydroxyl group contained in R ¹ will be described. Generally, the carbon atom to which the hydroxyl group is directly bonded can be classified into three types of primary carbon, secondary carbon and tertiary carbon depending on the number of carbon bonded to the carbon to which the hydroxyl group is bonded.

Specifically, as the primary carbon hydroxyl group-containing organic group,
Etc.

Specifically, as the secondary carbon hydroxyl group-containing organic group,
Etc.

Specifically, as the tertiary carbon hydroxyl group-containing organic group,
Etc.

  Among these, from the viewpoint of steric hindrance, the hydroxyl group bonded to the primary and secondary carbons is preferably a hydroxyl group bonded to the primary carbon from the viewpoint of reactivity.

Next, Y ¹ is a monovalent hydroxyl group-containing organic group having 1 to 10 carbon atoms and having a hydroxyl group bonded to primary to tertiary carbon as described above, and Y represents the specific structure of R ^1. explain. In the following structural formulas, Y represents Y ¹ or simply a hydroxyl group.

(In the formula, l, m and n are integers, and are l: 1 to 10, m: 1 to 10, n: 1 to 5)

(Wherein X ⁶ and X ⁹ are F or CF ₃ , X ⁷ and X ⁸ are H or F, o + p + q is 1 to 10; r is 0 or 1; s and t are 0 or 1)
Etc.

Specific examples of the hydroxyl group-containing structural unit (1) include the following. Y ¹ represents a C 1-10 monovalent hydroxyl group-containing organic group having a hydroxyl group bonded to primary to tertiary carbon, and Y represents Y ¹ or simply a hydroxyl group.

(N is an integer from 0 to 5)

More specifically,
(N is an integer of 0 to 5).

Among these, from the point that the reactivity with the unsaturated carboxylic acid (b) is rich, and the solubility in the acrylic monomer (II) is good,
(N is an integer of 0 to 5) is particularly preferable.

  The hydroxyl group-containing fluoropolymer (a) may further contain a monomer unit that does not contain a hydroxyl group in the structural unit as long as the solubility in the acrylic monomer (II) is not impaired. As specific examples of such monomer units, all of the structural units A and M described in WO 02/18457 can be used without any hydroxyl group.

Among them, especially from the point of good solubility in acrylic monomer (II),
-CH ₂ -CF ₂ -,
_{-CH 2 -CF (CF 3) -} ,
Is preferred.

Among these, from the point that the reactivity with the unsaturated carboxylic acid (b) is rich, and the solubility in the acrylic monomer (II) is good,
(In the formula, n is an integer of 0 to 5; the ratio of p and q is 20/80 to 99/1 in molar ratio)
Etc.

  The hydroxyl group-containing fluoropolymer (a) can be obtained by (co) polymerizing monomers corresponding to the respective structural units by a known method. As the polymerization method, a radical polymerization method, an anionic polymerization method, a cationic polymerization method or the like can be used. Among them, the monomers exemplified for obtaining the hydroxyl group-containing polymer of the present invention have good radical polymerizability, and are easy to control the quality such as the composition and molecular weight, and the radical polymerization method is easy to industrialize. Preferably used.

  In order to start radical polymerization, the means is not limited as long as it proceeds radically, but for example, it is started by organic or inorganic radical polymerization initiator, heat, light, or ionizing radiation. As the polymerization mode, solution polymerization, bulk polymerization, suspension polymerization, emulsion polymerization and the like can be used. The molecular weight is controlled by the concentration of the monomer used for the polymerization, the concentration of the polymerization initiator, the concentration of the chain transfer agent, the temperature, and the like. The copolymer composition can be controlled by the composition of the charged monomers.

  The number average molecular weight of the hydroxyl group-containing fluoropolymer (a) is about 2000 to 2000000, preferably about 5000 to 500000.

(B) Unsaturated carboxylic acid The unsaturated carboxylic acid or its acid halide is esterified with the hydroxyl group of the hydroxyl group-containing fluoropolymer (a) to give a carbon-carbon dioxygen derived from the unsaturated carboxylic acid to the fluoropolymer. A double bond (unsaturated group) is introduced to give an unsaturated group-containing fluoropolymer (I).

As unsaturated carboxylic acid (b), Formula (4):
^{CX 11 X 12 = CX 13 -} (R 3) c -COM
Wherein X ¹¹ and X ¹² are the same or different and are a fluorine atom or a hydrogen atom; X ¹³ is a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or a trifluoromethyl group; M is —OH or a halogen atom; ³ is preferably a compound represented by divalent organic group; c is 0 or 1) from the viewpoint of good esterification reactivity.

  When M is a halogen atom (in the case of an acid halide), a chlorine atom or a fluorine atom is preferable.

R ³ is a linear or branched alkylene group, a fluoroalkylene group, a perfluoroalkylene group, which may contain an ether bond and / or an ester bond in the chain, and further having 1 to 10 carbon atoms, particularly carbon. A C 1-3 alkylene group is preferred.

Specific preferred examples of the unsaturated carboxylic acid represented by the formula _{(4), CH 2 = CHCOOH} , CH 2 = C (CH 3) COOH, CH 2 = CHCOCl, CH 2 = C (CH 3) COCl, vinyl acetate , Crotonic acid, cinnamic acid, 3-allyloxypropionic acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, maleic anhydride, fumaric acid, fumaric acid monoester, vinyl phthalate, pyromellitic acid hydrocarbon unsaturated carboxylic acid or halide thereof acids such as _{vinyl; CH 2 = C (Cl)} COOH, CH 2 = CFCOCl, CH 2 = C (Cl) COCl, CH 2 = CFCOOH, halogen such as CH ₂ = CFCOF Examples thereof include unsaturated carboxylic acids or acid halides thereof.

Of these, from the viewpoint of good solubility in acrylic monomer (II) and good esterification reactivity, CH ₂ = CHCOOH, CH ₂ = C (CH ₃ ) COOH, CH ₂ = CHCOCl, _{CH 2 = C (CH 3)} COCl, CH 2 = CFCOOH, CH 2 = C (Cl) COOH, CH 2 = CFCOCl, CH 2 = C (Cl) COCl, are CH ₂ = CFCOF preferred.

  The technique and conditions for esterifying the unsaturated carboxylic acid or its acid halide with the hydroxyl group-containing fluoropolymer (a) are not particularly limited, and conventionally known techniques and conditions for esterification reactions can be employed.

  For example, when using a free unsaturated carboxylic acid, it may be esterified by stirring and mixing with a suitable dehydrating agent at a temperature of about 70 ° C. to 110 ° C.

  Moreover, when using unsaturated carboxylic acid halide, it can stir and mix unsaturated carboxylic acid halide with the hydroxyl-containing fluoropolymer (a) at the temperature of about -20 degreeC-40 degreeC, and can be made to esterify. .

  When an acid halide is used, HCl and HF are by-produced by the reaction, but it is desirable to add an appropriate base for the purpose of capturing them. Examples of the base include tertiary amines such as pyridine, N, N-dimethylaniline, tetramethylurea and triethylamine, and magnesium metal. In addition, an inhibitor for inhibiting the polymerization reaction of the raw material α, β-unsaturated carboxylic acid and the carbon-carbon double bond in the obtained curable fluorine-containing polymer is allowed to coexist. Also good. Examples of the inhibitor include hydroquinone, t-butyl hydroquinone, hydroquinone monomethyl ether and the like.

  The unsaturated carboxylic acid (b) is preferably used in an amount of 0.1 to 5 equivalents, more preferably 0.2 to 2 equivalents, relative to the hydroxyl groups of the hydroxyl group-containing fluoropolymer (a).

  The unsaturated group-containing fluoropolymer (I) thus obtained contains an ethylenic carbon-carbon double bond derived from an unsaturated carboxylic acid in the side chain, and the side chain and the polymer main chain are bonded by an ester bond. It is what has been.

  The heat-resistant transparent solventless curable fluorine-containing resin composition of the present invention is a composition in which the unsaturated group-containing fluorine-containing polymer (I) is dissolved in the acrylic monomer (II).

  The acrylic monomer (II) used in the present invention has one or more radical polymerizable unsaturated groups such as an acryloyl group, a methacryloyl group, an α-fluorinated acryloyl group, and a 2-chlorinated acryloyl group. Monomer.

  The radically polymerizable unsaturated group in the acrylic monomer (II) is preferably one from the viewpoint that the unsaturated group-containing fluoropolymer (I) has high solubility and low viscosity, and is also curable. Two or more are preferable from the point that the strength of the cured product prepared and cured in the composition is good, and three or more is preferable from the point that the curing rate of the curable composition is good.

  Acrylic monomers (II) include methacrylic acid monomers such as methacrylic acid and methacrylic acid esters; acrylic acid monomers such as acrylic acid and acrylate esters; (Meth) acrylic acid-based monomers; 2-fluoroacrylic acid-based monomers such as 2-fluoroacrylic acid and 2-fluoroacrylic acid esters; fluorine-containing 2-fluoroacrylic acid-based monomers that are fluorinated products thereof Etc.

  Specific examples of the methacrylic acid monomer include methyl methacrylate (MMA), methacrylic acid (MA), ethyl methacrylate (EMA), n-butyl methacrylate (nBMA), isobutyl methacrylate (iBMA), and 2-ethylhexyl methacrylate. 2-hydroxyethyl methacrylate (HEMA), phenyl methacrylate, cyclohexyl methacrylate, 3- (trimethoxysilyl) propyl methacrylate (MSPM), 2- (phenylphosphoryl) ethyl methacrylate (phenyl-PM), 2-hydroxy-3- ( β-naphthoxy) methacrylate (HNPM), N-phenyl-N- (2-hydroxy-3-methacryloxy) propylglycine (NPG-GMA, etc.) Luric acid ester (usually called monofunctional methacrylate); ethylene glycol dimethacrylate (EDMA or 1GMA), diethylene glycol dimethacrylate (DiEDMA), triethylene glycol dimethacrylate (TriEDMA), 1,4-butanediol dimethacrylate (1,4-BuDMA), 1,3-butanediol dimethacrylate (1,3-BuDMA), 1,6-hexanediol dimethacrylate (16HXMA), 2,2-bis [4- (2-hydroxy-3 -Methacryloxypropoxy) phenyl] propane (Bis-GMA), 2,2-bis (4-methacryloxyphenyl) propane (BPDMA), 2,2-bis (4-methacryloxyethoxyphenyl) propane (Bis-MEPP) 2 , 2-bis (4-methacryloxypolyethoxyphenyl) propane (Bis-MPEPP), di (methacryloxyethyl) trimethylhexamethylenediurethane (UDMA), trimethylolpropane trimethacrylate (TMPA), pentaerythritol trimethacrylate, penta Examples thereof include methacrylic acid esters having two or more unsaturated groups such as erythritol tetramethacrylate (PETMA) and dipentaerythritol hexamethacrylate (DPEHMA) (usually called polyfunctional methacrylate).

  Examples of acrylic acid monomers include acrylic acid esters corresponding to the above methacrylic acid monomers, and monomers in which the α-position of acrylic acid is substituted with a chlorine atom.

  As the fluorine-containing acrylic monomer, a monomer in which the ester portion of the above methacrylic acid monomer and acrylic acid monomer is a fluorine-containing group, the α-position of acrylic acid is a fluorine atom or trifluoromethyl Examples thereof include α-fluorinated methacrylic acid ester or α-fluorinated acrylate ester substituted with a group.

Examples of the monomer in which the ester portion of the methacrylic acid monomer and the acrylic acid monomer is a fluorine-containing group include CH ₂ ═C (CH ₃ ) COOCH ₂ CF ₃ (3FMA),
_{CH 2 = C (CH 3)} COOCH 2 CF 2 CF 2 H (4FMA),
_{CH 2 = C (CH 3)} COOCH 2 CF 2 CF 3 (5FMA),
_{CH 2 = C (CH 3)} COOCH 2 CF 2 CFHCF 3 (6FMA),
_{CH 2 = C (CH 3)} COOCH 2 (CF 2) 3 CF 2 H (8FMA),
_{CH 2 = C (CH 3)} COOCH 2 CH 2 (CF 2) 3 CF 3 (9FMA),
_{CH 2 = C (CH 3)} COOCH 2 (CF 2) 5 CF 2 H (12FMA),
_{CH 2 = C (CH 3)} COOCH 2 CH 2 (CF 2) 5 CF 3 (13FMA),
_{CH 2 = C (CH 3)} COOCH 2 CH 2 (CF 2) 7 CF 3 (17FMA),
_{CH 2 = C (CH 3)} COOCH (CF 3) 2 (HFIP-MA),
_{CH 2 = C (CH 3)} COOCH 2 CCH 3 (CF 3) 2 (6FNP-MA),
_{CH 2 = C (CH 3)} COOCH 2 CF (CF 3) OCF 2 CF 2 CF 3 (6FOn1-MA),
CH ₂ = CHCOOCH ₂ CF ₃ (3FA),
_{CH 2 = CHCOOCH 2 CF 2 CF} 2 H (4FA),
CH ₂ = CHCOOCH ₂ CF ₂ CF ₃ (5FA),
CH ₂ = CHCOOCH ₂ CF ₂ CFHCF ₃ (6FA),
_{CH 2 = CHCOOCH 2 (CF 2} ) 3 CF 2 H (8FA),
_{CH 2 = CHCOOCH 2 CH 2 (} CF 2) 3 CF 3 (9FA),
_{CH 2 = CHCOOCH 2 (CF 2} ) 5 CF 2 H (12FA),
_{CH 2 = CHCOOCH 2 CH 2 (} CF 2) 5 CF 3 (13FA),
_{CH 2 = CHCOOCH 2 CH 2 (} CF 2) 7 CF 3 (17FA),
_{CH 2 = CHCOOCH (CF 3)} 2 (HFIP-A),
_{CH 2 = CHCOOCH 2 CCH 3 (} CF 3) 2 (6FNP-A),
_{CH 2 = CHCOOCH 2 CF (CF} 3) OCF 2 CF 2 CF 3 (6FOn1-A)
Etc. can be illustrated.

Examples of the α-fluorinated methacrylate ester and α-fluorinated acrylic ester include:
_{CH 2 = CFCOOCH 2 CF 2 CF} 2 H (4FFA),
CH ₂ = CFCOOCH ₂ CF ₂ CF ₃ (5FFA),
_{CH 2 = CFCOOCH 2 (CF 2} ) 3 CF 2 H (8FFA),
_{CH 2 = CFCOOCH 2 (CF 2} ) 5 CF 2 H (12FFA),
_{CH 2 = CFCOOCH (CF 3)} 2 (HFIP-FA)
Etc. can be illustrated.

  Examples of the acrylic monomer as described above include methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, 3FMA, and the like, from the viewpoint of excellent solubility of the unsaturated group-containing fluoropolymer (I). 4FMA, 5FMA, 8FMA, 3FA, 4FA, 5FA, and 8FA are preferred. From the viewpoint of improving the strength and reaction rate of the cured product, methacrylic acid esters such as 16HXMA, TMPMA, EDMA, TriEDMA, DPEHMA, and PETMA, or acrylic acid esters corresponding to these methacrylic acid esters can be mentioned.

  The mass ratio of the unsaturated group-containing fluoropolymer (I) and the acrylic monomer (II) is preferably 95: 5 to 5:95, more preferably 80:20 to 20:80, and 70:30 to 30:70 is more preferable. When the mass ratio of the unsaturated group-containing fluoropolymer (I) and acrylic monomer (II) deviates from 95: 5 and the amount of the unsaturated group-containing fluoropolymer (I) increases, the viscosity increases. , Tend to be difficult to handle. Further, since the fluorine content decreases as the amount of the unsaturated group-containing fluoropolymer (I) decreases, the weather resistance, water / oil repellency, and antifouling properties of the cured product obtained by curing the curable composition are also reduced. Tends to decrease.

  The viscosity at 30 ° C. of the curable resin composition is preferably 5 mPa · s or more because the dripping is excessive when the viscosity is too low, and the handleability is lowered. From the viewpoint that the thin film formability is good, 10 mPa · s or more is more preferable, and 50 mPa · s or more is more preferable from the viewpoint that curing shrinkage during curing is small. Further, the viscosity at 30 ° C. of the curable resin composition is preferably 100000 mPa · s or less from the viewpoint of good handleability, and from the viewpoint that the curable composition spreads over the details during the molding process. s or less is more preferable, and 20000 mPa · s or less is more preferable from the viewpoint that the leveling (surface smoothness) is good when a thin film is formed.

  The composition of the present invention is obtained by esterifying the hydroxyl group-containing fluoropolymer (a) and the unsaturated carboxylic acid or its acid halide (b), removing impurities by purification, and drying. The unsaturated group-containing fluoropolymer (I) thus obtained can be produced by dissolving it in the acrylic monomer (II).

  By the way, since a leaving group or the like is usually generated in the esterification reaction, the unsaturated group-containing fluoropolymer (I) is purified by reprecipitation or washing with water and then dried. When the drying temperature is raised in this drying step, since unsaturated groups are present in the unsaturated group-containing fluoropolymer (I), the addition polymerization reaction proceeds, resulting in a gelled product that is insoluble in the solvent. There is. In order to avoid gelation, an appropriate amount of a polymerization inhibitor such as hydroquinone is usually added. However, even if gelation can be suppressed, the polymerization inhibitor remains in the unsaturated group-containing fluoropolymer (I). There is a problem that the curing rate of the final composition becomes extremely slow or does not cure.

  Therefore, as a result of intensive studies on conditions under which gelation does not occur even without adding a polymerization inhibitor, the present inventors obtained gelation without occurring by maintaining the temperature at the time of drying after purification at 60 ° C. or less. It has been found that a uniform curable composition can be obtained without solvent by dissolving the unsaturated group-containing fluoropolymer (I) in the acrylic monomer (II).

  That is, in the present invention, the hydroxyl group-containing fluoropolymer (a) and the unsaturated carboxylic acid or the acid halide (b) thereof are esterified, and then impurities are removed by purification. Is a method for producing a composition of the present invention, comprising dissolving an unsaturated group-containing fluoropolymer (I) obtained by drying at a temperature of 40 ° C. or less in an acrylic monomer (II) Also related.

  The curable resin composition of the present invention can be crosslinked by irradiation with active energy rays.

  An active energy ray curing initiator, for example, generates radicals and cations only when irradiated with electromagnetic waves in a wavelength region of 350 nm or less, that is, ultraviolet rays, electron beams, X rays, γ rays, and the like, and is a curable fluorine-containing polymer. These act as a catalyst for initiating curing (crosslinking reaction) of the carbon-carbon double bond, and those that generate radicals and cations with ultraviolet light, particularly those that generate radicals are used.

  According to the curable resin composition of the present invention, the curing reaction can be easily started by the active energy ray, and there is no need for heating at a high temperature, and a curing reaction is possible at a relatively low temperature. This is preferable in that it can be applied to a base material that is easily deformed, decomposed or colored by heat, such as a transparent resin base material.

  The active energy ray curing initiator in the composition of the present invention is the type of the carbon-carbon double bond of the side chain in the unsaturated group-containing fluoropolymer (I) (whether radical reactive or cationic reactive), The type of active energy ray to be used (wavelength range, etc.) and irradiation intensity are selected as appropriate. Generally, it contains an unsaturated group containing a radical-reactive carbon-carbon double bond using an active energy ray in the ultraviolet region. Examples of the initiator for curing the fluoropolymer (I) include the following.

(Acetophenone series)
Acetophenone, chloroacetophenone, diethoxyacetophenone, hydroxyacetophenone, α-aminoacetophenone, hydroxypropiophenone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinepropan-1-one, etc.

(Benzoin)
Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyldimethyl ketal, etc.

(Benzophenone series)
Benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, hydroxy-propylbenzophenone, acrylated benzophenone, Michler's ketone, etc.

(Thioxanthones)
Thioxanthone, Chlorothioxanthone, Methylthioxanthone, Diethylthioxanthone, Dimethylthioxanthone, etc.

(Other)
Benzyl, α-acyl oxime ester, acyl phosphine oxide, glyoxy ester, 3-ketocoumarin, 2-ethylanthraquinone, camphorquinone, anthraquinone, etc.

  Moreover, compatibility with a fluorine-containing polymer can be improved by introducing a fluorine atom or a fluorine-containing organic group into the active energy ray initiator itself.

  Specifically, it is preferable that the initiator contains a fluorine-containing alkyl group, a fluorine-containing alkylene group, a fluorine-containing alkyl group having an ether bond, or a fluorine-containing alkylene group having an ether bond. Fluorine-containing carboxylic acid (polyvalent carboxylic acid) having a fluorine-containing organic group or the like introduced by an ester bond, fluorine-containing carboxylic acid (polyvalent carboxylic acid) is introduced to an initiator having an amino group by an amide bond Examples include structures.

  By introducing a fluorine-containing organic group into the initiator, even in a fluorine-containing polymer having a high fluorination rate, it is preferable in terms of good compatibility and improvement in curing reactivity and film transparency.

  Moreover, you may add photoinitiator adjuvants, such as amines, sulfones, and sulfines, as needed.

  Moreover, the following can be illustrated as an initiator which hardens the unsaturated group containing fluoropolymer (I) which has a cation reactive carbon-carbon double bond.

(Onium salt)
Iodonium salt, sulfonium salt, phosphonium salt, diazonium salt, ammonium salt, pyridinium salt, etc.

(Sulfone compound)
β-ketoesters, β-sulfonylsulfones and their α-diazo compounds, etc.

(Sulfonate esters)
Alkyl sulfonate, haloalkyl sulfonate, aryl sulfonate, imino sulfonate, etc.

(Other)
Sulfonimide compounds, diazomethane compounds, etc.

  Also in these cation-reactive active energy ray initiators, compatibility with the fluorine-containing polymer can be improved in the same manner as described above by introducing a fluorine atom or a fluorine-containing organic group.

  You may add a hardening | curing agent to the curable resin composition of this invention as needed. Examples of the curing agent include the aforementioned polyfunctional methacrylic acid ester or acrylic acid ester.

  In the composition of the present invention, the amount of the active energy ray curing initiator added is the content of the carbon-carbon double bond in the unsaturated group-containing fluoropolymer (I) and the acrylic monomer (II), Depending on the presence or absence of other curing agents and the amount of curing agents used, and further, depending on the initiator used, the type of active energy rays, and the amount of irradiation energy (strength and time, etc.), the curing agent is not used. In some cases, 0.01 to 30 parts by mass, further 0.05 to 20 parts by mass, most preferably 100 parts by mass of the unsaturated group-containing fluoropolymer (I) and acrylic monomer (II). Preferably, it is 0.1-10 mass parts.

  Specifically, 0.05 to 50 mol% with respect to the content (number of moles) of carbon-carbon double bonds contained in the unsaturated group-containing fluoropolymer (I) and acrylic monomer (II). , Preferably 0.1 to 20 mol%, most preferably 0.5 to 10 mol%.

  When a curing agent is used, the content (in moles) of carbon-carbon double bonds contained in the unsaturated group-containing fluoropolymer (I) and acrylic monomer (II) and the carbon of the curing agent -0.05-50 mol% with respect to the total number of moles of a carbon unsaturated bond, Preferably it is 0.1-20 mol%, Most preferably, it is 0.5-10 mol%.

  When a curing agent is used, the amount of curing agent used is appropriately selected according to the target hardness and refractive index, the type of curing agent, the content of the curable group of the curable fluorinated polymer used, and preferably curable. It is 1-80 mass% with respect to a fluorine-containing polymer, Preferably it is 5-70 mass%, More preferably, it is 10-50 mass%. If the addition amount of the curing agent is too large, the refractive index tends to increase, which is not preferable.

  The composition of the present invention may contain various additives as necessary in addition to the above-mentioned compounds.

  Examples of such additives include leveling agents, viscosity modifiers, light stabilizers, moisture absorbers, pigments, dyes, and reinforcing agents.

  The composition of the present invention can also contain inorganic compound fine particles for the purpose of increasing the hardness of the cured product.

  The inorganic compound fine particles are not particularly limited, but compounds having a refractive index of 1.5 or less are preferable. Specifically, magnesium fluoride (refractive index 1.38), silicon oxide (refractive index 1.46), aluminum fluoride (refractive index 1.33-1.39), calcium fluoride (refractive index 1.44) Fine particles such as lithium fluoride (refractive index 1.36 to 1.37), sodium fluoride (refractive index 1.32 to 1.34), thorium fluoride (refractive index 1.45 to 1.50) are desirable. . The particle diameter of the fine particles is desirably sufficiently smaller than the wavelength of visible light in order to ensure the transparency of the low refractive index material. Specifically, it is preferably 100 nm or less, particularly 50 nm or less.

  When using inorganic compound fine particles, it should be used in the form of an organic sol dispersed in advance in an organic dispersion medium in order not to lower the dispersion stability in the composition and the adhesion in the low refractive index material. Is desirable. Furthermore, in order to improve the dispersion stability of the inorganic compound fine particles and the adhesion in the low refractive index material in the composition, the surface of the inorganic fine particle compound may be modified in advance using various coupling agents. it can. Examples of various coupling agents include organically substituted silicon compounds; metal alkoxides such as aluminum, titanium, zirconium, antimony or mixtures thereof; salts of organic acids; coordination compounds bonded to coordination compounds, and the like. .

  The curable resin composition of the present invention can be used for various applications in various forms.

  For example, a cured film can be formed and used for various purposes. As a method of forming the film, a known method suitable for the application can be employed. For example, when it is necessary to control the film thickness, roll coating, gravure coating, micro gravure coating, flow coating, bar coating, spray coating, die coating, spin coating, dip coating, etc. are used. it can.

  The coating obtained by applying the curable resin composition of the present invention to a substrate and drying it can be photocured by irradiating active energy rays such as ultraviolet rays, electron beams or radiation.

  When cured, the carbon-carbon double bond in the unsaturated group-containing fluoropolymer (I) is polymerized intermolecularly or with the acrylic monomer (II), or between the acrylic monomers (II). Is polymerized, and the carbon-carbon double bonds in the resulting crosslinked polymer are reduced or eliminated. As a result, the resin hardness is increased, the mechanical strength is improved, the wear resistance, the scratch resistance is improved, and further, the resin becomes insoluble in the solvent dissolved before curing, It becomes insoluble in many other types of solvents.

  The cured product obtained by curing is excellent in transparency, for example, the transmittance of light having a wavelength of 400 to 800 nm is 80% or more, further 90% or more.

  Although the curable resin composition of the present invention may form a film, it is particularly useful as a molding material for various molded products. As the molding method, extrusion molding, injection molding, compression molding, blow molding, transfer molding, stereolithography, nanoimprinting, vacuum molding and the like can be adopted.

  Applications of the curable resin composition of the present invention include, for example, a sealing member, an optical material, a photoelectronic imaging tube, various sensors, an antireflection material, and the like.

  Examples of usage of the sealing member include packages (encapsulation) and mounting of light-emitting elements such as light-emitting diodes (LEDs), EL elements, and nonlinear optical elements, and optical functional elements such as light-receiving elements such as CCD, CMOS, and PD. Can be illustrated. Moreover, sealing materials (or fillers) for optical members such as lenses for deep ultraviolet microscopes are also included. Sealed light elements are used in various places, but non-limiting examples include light emission from high-mount stop lamps, meter panels, mobile phone backlights, and light sources for remote control devices for various electrical products. Elements: Camera autofocus, CD / DVD optical pickup light receiving element, and the like.

  Since the optical material particularly contains fluorine, the optical material has a low refractive index. For example, it is useful as an optical transmission medium. In particular, cladding material of plastic clad optical fiber whose core material is quartz or optical glass, cladding material of all plastic optical fiber whose core material is plastic, anti-reflection coating material, lens material, optical waveguide material, prism material, optical window It can be used for optical materials such as materials, optical storage disk materials, nonlinear optical elements, hologram materials, photolithographic materials, and light emitting element sealing materials. It can also be used as a material for optical devices. As optical devices, optical devices such as optical waveguides, OADMs, optical switches, optical filters, optical connectors, multiplexers / demultiplexers, and other optical devices are known and useful for forming these devices. Material. Furthermore, various functional compounds (non-linear optical materials, fluorescent light-emitting functional dyes, photorefractive materials, etc.) are contained and used as functional elements for optical devices such as modulators, wavelength conversion elements, and optical amplifiers. Is suitable.

  As a sensor application, there is an effect such as an improvement in sensitivity of an optical sensor or a pressure sensor, and protection of the sensor by water / oil repellency characteristics, which is useful.

  In addition, it can also be used as a sealing member material for electronic semiconductors, a water and moisture resistant adhesive, and an adhesive for optical components and elements.

  Examples of the use can be exemplified as described above, but are not limited thereto.

  The measurement methods employed in this specification are summarized below.

(1) NMR analyzer: manufactured by BRUKER
¹ H-NMR measurement conditions: 300 MHz (tetramethylsilane = 0 ppm)
¹⁹ F-NMR measurement conditions: 282 MHz (trichlorofluoromethane = 0 ppm)

(2) IR analyzer: Fourier transform infrared spectrophotometer 1760X manufactured by PERKIN ELMER
Conditions: Measure at room temperature.

(3) Number average molecular weight and weight average molecular weight Using gel permeation chromatography (GPC), GPC HLC-8020 manufactured by Tosoh Corporation was used, and a column manufactured by Shodex (one GPC KF-801, GPC KF- The number average molecular weight and the weight average molecular weight are calculated from the data measured by flowing tetrahydrofuran (THF) as a solvent at a flow rate of 1 ml / min using one 802 and two GPC KF-806M in series.

(4) Fluorine content (% by mass)
By burning 10 mg of sample by the oxygen flask combustion method, absorbing the decomposition gas in 20 ml of deionized water, and measuring the fluorine ion concentration in the absorption liquid by the fluorine selective electrode method (fluorine ion meter, model 901 manufactured by Orion) Ask.

(5) Viscosity (mPa · s)
Using a cone plate viscometer CV-1E manufactured by Tokai Yagami Co., Ltd., the viscosity at 25 ° C. is measured under the condition of 100 rpm using CP-100 cone, and a stable value is adopted for 60 seconds.

(6) Refractive index (n _D )
Measurement is performed using an Abbe refractometer manufactured by Atago Optical Instruments Co., Ltd. at 25 ° C. using sodium D line (589 nm) as a light source.

(7) Thermal decomposition temperature (℃)
Using a thermogravimeter (TGA-50 manufactured by Shimadzu Corporation), measurement is performed under a nitrogen atmosphere condition at a temperature rising rate of 10 ° C./min, and evaluation is performed at a temperature of 1% mass reduction.

(8) Light transmittance (%)
A spectral transmittance curve of a sample (cured film) having a thickness of about 100 μm at a wavelength of 300 to 800 nm is measured using a self-recording spectrophotometer (U-3310 (trade name) manufactured by Hitachi, Ltd.). A transmittance value at 550 nm with high visibility is adopted as a representative value. Moreover, in the test result of heat resistance, the spectrum is shown.

(9) Solvent resistance A sample of 10 mm × 10 mm × 0.1 mm is immersed in 20 mL of butyl acetate, and the state after lapse of 8 hours at room temperature is visually observed.

(10) Heat resistance Each sample is held at a temperature of 180 ° C for 1 hour, and the change in appearance is visually observed.

Synthesis Example 1 (Synthesis of high molecular weight homopolymer of fluorine-containing allyl ether having a hydroxyl group)
In a 100 ml glass four-necked flask equipped with a stirrer and a thermometer, perfluoro- (1,1,9,9-tetrahydro-2,5-bistrifluoromethyl-3,6-dioxanonenol) was added. (AEH1):
20.4g
After adding 10.5 g of the 8.0 wt% perfluorohexane solution and thoroughly purging with nitrogen, the mixture was stirred at 20 ° C. for 24 hours under a nitrogen stream to produce a highly viscous solid.

  A solution obtained by dissolving the obtained solid in diethyl ether was poured into perfluorohexane, separated and vacuum dried to obtain 13.2 g of a colorless and transparent polymer.

When this polymer was analyzed by ¹⁹ F-NMR, ¹ H-NMR analysis, and IR analysis, it was a fluorine-containing polymer consisting only of the structural unit of the fluorine-containing allyl ether and having a hydroxyl group at the end of the side chain. The number average molecular weight measured by GPC analysis using tetrahydrofuran (THF) as a solvent was 86,000, and the weight average molecular weight was 108,000. This polymer is referred to as polymer (a).

Synthesis Example 2 (Synthesis of a low molecular weight homopolymer of a fluorine-containing allyl ether having a hydroxyl group)
Into a 300 ml glass four-necked flask equipped with a stirrer and a thermometer, 100.2 g of AEH1 and 42.5 g of HCFC-225 (mixture of CF ₃ CF ₂ CHCl / CClF ₂ CF ₂ CHCl) were started. After adding 3.36 g of perbutyl PV (peroxide polymerization initiator manufactured by Nippon Oil & Fats Co., Ltd.) as an agent and sufficiently purging with nitrogen, the mixture was stirred at 65 ° C. for 12 hours under a nitrogen stream. Solution.

  The obtained polymer solution was poured into perfluorohexane, separated and vacuum dried to obtain 61.8 g of a colorless and transparent polymer.

When this polymer was analyzed by ¹⁹ F-NMR, ¹ H-NMR analysis, and IR analysis, it was a fluorine-containing polymer consisting only of the structural unit of the fluorine-containing allyl ether and having a hydroxyl group at the end of the side chain. The number average molecular weight measured by GPC analysis using tetrahydrofuran (THF) as a solvent was 11000, and the weight average molecular weight was 15700. This polymer is referred to as polymer (b).

Synthesis Example 3 (Synthesis of low molecular weight copolymer of fluorine-containing allyl ether having a hydroxyl group)
To a 100 ml glass four-necked flask equipped with a stirrer and a thermometer, 9.6 g of AEH1 and methyl 9H, 9H-perfluoro-2,5-dimethyl-3,6-dioxa-8-nonenoic acid (AEE1) ):
9.6g, and stir well,
After adding 2.0 g of an 8.0 wt% perfluorohexane solution and thoroughly purging with nitrogen, the mixture was stirred at 20 ° C. for 20 hours under a nitrogen stream to produce a highly viscous solid.

  A solution obtained by dissolving the obtained solid in acetone was poured into a solution of HCFC225 / n-hexane = 1/1, separated and vacuum dried to obtain 15.5 g of a colorless and transparent polymer.

This polymer was analyzed by ¹⁹ F-NMR, ¹ H-NMR analysis, and IR analysis. As a result, fluorine-containing copolymer composed of the above-mentioned hydroxyl group-containing fluorine-containing allyl ether and a fluorine-containing allyl ether structural unit having a methyl ester structure. It was a coalescence. The composition ratio was determined to be 42:58 (molar ratio) by NMR. The number average molecular weight measured by GPC analysis using tetrahydrofuran (THF) as a solvent was 7200, and the weight average molecular weight was 11000. This polymer is referred to as polymer (c).

Synthesis Example 4 (Synthesis of fluorinated allyl ether having hydroxyl group and vinylidene fluoride copolymer)
In a 300 ml stainless steel autoclave equipped with a valve, pressure gauge, and thermometer, 34.2 g of AEH1, 200 g of CH ₃ CCl ₂ F (HCFC-141b), 50 mass of dinormal propyl peroxycarbonate (NPP) A 0.16 g% methanol solution was added, and the inside of the system was sufficiently replaced with nitrogen gas while cooling with a dry ice / methanol solution. Next, 5.8 g of vinylidene fluoride (VdF) was charged from the valve, and the reaction was performed while shaking at 40 ° C. As the reaction progressed, the gauge pressure in the system decreased from 4.4 MPaG before the reaction to 0.98 MPaG after 12 hours.

  At this point, the unreacted monomer was released, the precipitated solid was taken out, dissolved in acetone, and then reprecipitated with a mixed solvent of hexane and toluene (50/50) to separate the copolymer. This copolymer was vacuum-dried until a constant weight was obtained, to obtain 31.2 g of a copolymer.

The composition ratio of this copolymer was analyzed by ¹ H-MNR analysis and ¹⁹ F-NMR analysis, whereby the hydroxyl group-containing fluorine-containing allyl ether / VdF was 55/45 (mol%). Moreover, the number average molecular weight measured by GPC analysis using THF as a solvent was 12000, and the weight average molecular weight was 18000. This polymer is referred to as polymer (d).

Synthesis example 5
4.1 g of polymer (a) was weighed and dissolved in 40 g of methyl isobutyl ketone (MIBK) previously dehydrated with molecular sieves 4A, and charged into a 100 ml glass four-necked flask equipped with a stirrer and a thermometer. Thereafter, 1.05 g of pyridine was added, and then 0.99 g of ₂ -fluoroacrylic acid fluoride (CH ₂ = CFCOF) was added dropwise from an addition funnel in an ice bath, and the mixture was sufficiently stirred and homogenized. After stirring for 2 hours, the temperature was returned to room temperature. Stirring was continued for another 4 hours.

The MIBK solution after the reaction was placed in a separatory funnel, washed with water, washed with 2% hydrochloric acid, washed with 5% NaCl, and further washed with water. The organic layer was separated and dried over anhydrous magnesium sulfate.
Thereafter, the reaction solution was concentrated with a rotary evaporator, the solvent was removed by a casting method, and the precipitated solid was dissolved again in a small amount of acetone. The polymer was purified by reprecipitation of this solution in a sufficiently large amount of n-hexane. This purification operation was repeated a total of 3 times to obtain 3.4 g of a viscous polymer.

  All of these post-treatment operations were performed so as not to exceed 60 ° C. The same applies to the subsequent synthesis examples.

When this polymer was examined by ¹⁹ F-NMR, ¹ H-NMR analysis, and IR analysis, the formula (a-F):
The polymer was (m: n = 50.2: 49.8). This unsaturated group-containing polymer is referred to as polymer (a-F50).

Synthesis Example 6
In Synthesis Example 5, the reaction was performed in the same manner except that the amount of pyridine was 0.82 g and the amount of 2-fluoroacrylic acid fluoride was 0.84 g, and m: n = 85: 15 in formula (a-F). 3.2 g of an unsaturated group-containing polymer was obtained. This unsaturated group-containing polymer is referred to as polymer (a-F85).

Synthesis example 7
In Synthesis Example 5, the reaction was performed in the same manner except that the polymer (b) was used in place of the polymer (a), and an unsaturated group-containing polymer of m: n = 50: 50 in the formula (a-F) was 2 .3 g was obtained. This unsaturated group-containing polymer is referred to as polymer (b-F50).

Synthesis Example 8
In Synthesis Example 5, the reaction was performed in the same manner except that the polymer (b) was used instead of the polymer (a), the amount of pyridine was 0.82 g, and the amount of 2-fluoroacrylic acid fluoride was 0.84 g. In the formula (a-F), 2.8 g of a polymer having m: n = 85: 15 was obtained. This unsaturated group-containing polymer is referred to as polymer (b-F85).

Synthesis Example 9
4 g of the polymer (b) synthesized in Synthesis Example 2 was weighed and dissolved in 40 g of methyl isobutyl ketone (MIBK) previously dehydrated with molecular sieves 4A, and placed in a 200 ml glass four-necked flask equipped with a stirrer and a thermometer. Prepared. Thereafter, 0.6 g of triethylamine was added, and then 0.57 g of methallylic acid chloride (CH ₂ ═C (CH ₃ ) COCl) was dropped from an addition funnel in an ice bath, and the mixture was sufficiently stirred for homogenization. . After stirring for 2 hours, the temperature was returned to room temperature. After completion of the dropwise addition, the temperature was raised to room temperature and stirring was continued for 4 hours.

  The MIBK solution after the reaction was placed in a separatory funnel, washed with water, washed with 2% hydrochloric acid, washed with 5% NaCl, and further washed with water. The organic layer was separated and dried over anhydrous magnesium sulfate.

Thereafter, the reaction solution was concentrated with a rotary evaporator, the solvent was removed by a casting method, and the precipitated solid was dissolved again in a small amount of acetone. The polymer was purified by reprecipitation of this solution in a sufficiently large amount of n-hexane. This purification operation was repeated a total of 3 times to obtain 3.1 g of a viscous polymer. When this polymer was examined by ¹⁹ F-NMR, ¹ H-NMR analysis, and IR analysis,
The polymer was (m: n = 48: 52). This unsaturated group-containing polymer is referred to as polymer (b-M48).

Synthesis Example 10
In Synthesis Example 9, the reaction was carried out in the same manner except that 0.48 g of acrylic acid chloride was used instead of methallylic acid chloride, and an unsaturated group-containing polymer (m: n = 51: 49) represented by the following formula 3 0.2 g was obtained. This unsaturated group-containing polymer is referred to as polymer (b-A51).

Synthesis Example 11
4 g of the polymer (c) obtained in Synthesis Example 3 was weighed and dissolved in 40 g of methyl isobutyl ketone (MIBK) previously dehydrated with molecular sieves 4A, and a 100 ml glass four-necked flask equipped with a stirrer and a thermometer. Was charged. Thereafter, 0.24 g of pyridine was added, and then 0.25 g of ₂ -fluoroacrylic acid fluoride (CH ₂ = CFCOF) was added dropwise from an addition funnel in an ice bath, and the mixture was sufficiently stirred and homogenized. After stirring for 2 hours, the temperature was returned to room temperature. Stirring was continued for another 4 hours.

The MIBK solution after the reaction was placed in a separatory funnel, washed with water, washed with 2% hydrochloric acid, washed with 5% NaCl, and further washed with water. The organic layer was separated and dried over anhydrous magnesium sulfate.
Thereafter, the reaction solution was concentrated with a rotary evaporator, the solvent was removed by a casting method, and the precipitated solid was dissolved again in a small amount of acetone. The polymer was purified by reprecipitation of this solution in a sufficiently large amount of n-hexane. This purification operation was repeated a total of 3 times to obtain 2.2 g of a viscous polymer. When this polymer was examined by ¹⁹ F-NMR, ¹ H-NMR analysis, and IR analysis,
The polymer was (m: n: o = 21: 21: 58). This unsaturated group-containing polymer is referred to as polymer (c-F21).

Synthesis Example 12
In Synthesis Example 11, the reaction was performed in the same manner except that the polymer (d) was used instead of the polymer (c), pyridine was 0.32 g, and the amount of 2-fluoroacrylic acid fluoride was 0.31 g. 1.8 g of unsaturated group-containing polymer (m: n: o = 22: 23: 55) represented by the formula was obtained. This unsaturated group-containing polymer is referred to as polymer (d-F22).

Comparative Synthesis Example 1
4 g of the polymer (a) synthesized in Synthesis Example 1 was weighed and dissolved in 40 g of methyl isobutyl ketone (MIBK) previously dehydrated with molecular sieves 4A, and placed in a 100 ml glass four-necked flask equipped with a stirrer and a thermometer. Prepared. Thereafter, 0.004 g of dibutyltin dilaurate was added, and then 1.51 g of Karenz AOI (CH ₂ = CHCOOCH ₂ CH ₂ NCO) (hereinafter also referred to as AOI) manufactured by Showa Denko KK from a dropping funnel at room temperature. Was added dropwise and stirred well to make uniform. Then, it heated up to 45 degreeC, and returned to room temperature after stirring for 6 hours. By IR measurement, the absorption of -NCO derived from the isocyanate group of AOI disappeared, and the absorption of NH based on a urethane bond was newly observed, and it was confirmed that the reaction proceeded.

  After the reaction, the MIBK solution was concentrated with a rotary evaporator, the solvent was removed by a casting method, and the precipitated solid was dissolved again in a small amount of acetone. The polymer was purified by reprecipitation of this solution in a sufficiently large amount of n-hexane. This purification operation was repeated a total of 3 times to obtain 4.2 g of a viscous polymer.

  All of these post-treatment operations were performed so as not to exceed 60 ° C. The same applies to the subsequent synthesis examples.

When the obtained polymer was examined by ¹⁹ F-NMR, ¹ H-NMR analysis, and IR analysis,
It was a polymer containing a urethane bond (m: n = 50: 50) and an unsaturated group. This polymer is referred to as a polymer (Ua-AOI50).

Comparative Synthesis Example 2
Weighing 5.1 g of the polymer (d) obtained in Synthesis Example 4 and dissolving it in 40 g of methyl isobutyl ketone (MIBK) dehydrated in advance with Molecular Sieves 4A, a 100 ml glass bottle equipped with a stirrer and a thermometer. The flask was charged. Then, after adding 0.005 g of dibutyltin dilaurate, 0.75 g of Karenz MOI (CH ₂ = C (CH ₃ ) COOCH ₂ CH ₂ NCO) manufactured by Showa Denko KK was dropped from the dropping funnel at room temperature, Thoroughly stirred to homogenize. Then, it heated up to 45 degreeC, and returned to room temperature after stirring for 6 hours. By IR measurement, the absorption of -NCO derived from the isocyanate group of MOI disappeared, and the absorption of NH based on a urethane bond was newly observed, confirming that the reaction proceeded.

Thereafter, the reaction solution was concentrated with a rotary evaporator, the solvent was removed by a casting method, and the precipitated solid was dissolved again in a small amount of acetone. The polymer was purified by reprecipitation of this solution in a sufficiently large amount of n-hexane. This purification operation was repeated three times in total, and the obtained polymer was analyzed by ¹⁹ F-NMR, ¹ H-NMR analysis, and IR analysis.
It was a polymer containing a urethane bond and an unsaturated group (m: n: o = 22: 23: 55). This polymer is referred to as a polymer (Ud-MOI22).

Reference Example 1 (Effect of temperature on polymer)
The polymer (b-F50) obtained in Synthesis Example 7 was stored under conditions of 23 ° C., 60 ° C., and 100 ° C., and the amount of carbon-carbon double bonds was measured by IR at regular intervals to determine the reaction rate. Calculated by the following formula.

  The results are shown as a graph in FIG.

  In the graph of FIG. 1, it can be seen that the reaction rate is suppressed under the storage conditions of 23 ° C. and 60 ° C., and the reaction rate of the polymer stored at 100 ° C. is greatly increased. An increase in the reaction rate indicates that the double bond reacts with heat and gels. The gelled polymer becomes insoluble in the solvent, making it difficult to prepare a composition as a solvent-free cured resin. The polymer (b-F50) actually held at 100 ° C. for 72 hours gelled, and a composition could not be prepared.

Reference Example 2 (Evaluation of heat resistance of polymer only)
Heat resistance of the polymer (a-F50) used in the present invention having an unsaturated group via an ester bond and the comparative polymer (Ua-AOI50) having an unsaturated group via a urethane bond are measured using a thermogravimetric meter. And compared.

  Each sample was held in an atmosphere of 265 ° C., and when the amount of mass loss after 30 minutes was measured and compared, the polymer (a-F50) was reduced by 0.9% by mass, whereas for comparison, The polymer (Ua-AOI50) showed a decrease of 4.3% by weight. From this, it became clear that the polymer used in the present invention having an unsaturated group via an ester bond is excellent in heat resistance.

Example 1
A curable composition was prepared according to the following formulation. Table 1 shows the amount of each composition.
Polymer (a-F50) 50 parts by mass 4FA (CH ₂ = CHCOOCH ₂ C ₂ F ₄ H) 30 parts by mass Trimethylolpropane triacrylate (TMPA) 20 parts by mass Darocur MBF (manufactured by Ciba Specialty Chemicals) 4 parts by mass

  Next, the appearance (visual observation) and viscosity of the liquid composition at 25 ° C. of the prepared composition before curing were examined. Appearance evaluation criteria are shown below. The results are shown in Table 2.

(appearance)
○: Transparent and uniform, and the transmittance of light at 550 nm is 80% or more.
Δ: Partly cloudy (gel-like material) is observed.
X: Opaque and cloudy.

  Next, the appearance of the cured film prepared by curing in the following manner, fluorine content, refractive index (n), thermal decomposition temperature (Td), visible light transmittance (550 nm) (T), solvent resistance (butyl acetate) ) And heat resistance (180 ° C.). The results are shown in Table 2.

(Production of cured film)
NF-0100 (thickness 100 μm) made by Daikin Industries, Ltd., which is a fluororesin film for mold release, is spread on a glass plate, and is applied using an applicator so that the film thickness is about 100 μm. NF-0100 (thickness: 100 μm) made by Daikin Industries, Ltd., which is a fluororesin film for use, is stacked from the top, and a slide glass with a thickness of 1 mm is further placed thereon. It was cured by irradiating with ultraviolet rays at an intensity of ² U. Thereafter, the fluororesin film for release was peeled off to produce a cured film.

  The evaluation criteria for appearance, solvent resistance and heat resistance are shown below.

(appearance)
○: Transparent and uniform.
Δ: Some cloudiness is observed.
X: Opaque and cloudy.

(Solvent resistance)
○: No swelling is visually observed.
Δ: Swelling is visually observed.
X: Dissolve.

(Heat-resistant)
○: No change is visually observed.
Δ: Slight discoloration and turbidity are observed visually.
X: Discoloration, white turbidity, deformation, etc. that are clearly visible are observed.

Examples 2-10
A curable composition was prepared according to the formulation shown in Table 1, and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 2.

Comparative Examples 1-2
A curable composition was prepared according to the formulation shown in Table 1, and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 2.

  The abbreviations in Table 1 are the following compounds.

Unsaturated group-containing polymer a-F50: polymer synthesized in Synthesis Example 5 a-F85: polymer synthesized in Synthesis Example 6 b-F50: polymer synthesized in Synthesis Example 7 b-F85: polymer synthesized in Synthesis Example 8 b -M48: Polymer synthesized in Synthesis Example 9 b-A51: Polymer synthesized in Synthesis Example 10 c-F21: Polymer synthesized in Synthesis Example 11 d-F22: Polymer synthesized in Synthesis Example 12 Ua-AOI50: Comparison Polymer synthesized in Synthesis Example 1 Ud-MOI22: Polymer synthesized in Comparative Synthesis Example 2

Acrylic monomer 4FA: CH ₂ = CHCOOCH ₂ C ₂ F ₄ H
_{8FMA: CH 2 = CCH 3 COOCH} 2 C 4 F 8 H
_{HFIP-F: CH 2 = CFCOOC} (CH 3) 2 H
MMA: Methyl methacrylate TMPA: Trimethylolpropane triacrylate 16HX-A: 1,6-hexamethylene diacrylate PETA: Pentaerythritol tetraacrylate

UV polymerization initiator Darocur: Darocur MBF (manufactured by Ciba Specialty Chemicals)

Example 11
About the cured film obtained by hardening the curable composition prepared in Example 2, the light transmittance before and behind a high temperature holding test (260 degreeC, 5 minute holding) was measured. The results are shown in FIG. The solid line is the data before the test, and the broken line is the data after the test. Moreover, the photograph of the film before and behind a high temperature holding test is shown in FIG.

  2 and 3, it can be seen that the film obtained by curing the composition of the present invention maintains transparency even at very high temperatures.

Comparative Example 3
The cured film obtained by curing the curable composition prepared in Comparative Example 1 was measured for light transmittance before and after a high temperature holding test (260 ° C., holding for 5 minutes). The results are shown in FIG. The solid line is the data before the test, and the broken line is the data after the test. Moreover, the photograph of the film before and behind a high temperature holding test is shown in FIG. In FIG. 5, the film after the test was black, but it was actually yellowed to brown.

  4 and 5, it can be seen that the film obtained by curing a composition using a polymer containing a urethane bond is severely yellowed and the transmitted light intensity is greatly reduced.

Example 12
The cured film obtained by curing the curable composition prepared in Example 2 was measured for light transmittance before and after a high-temperature long-term retention test (160 ° C., retained for 7 days). The results are shown in FIG. The solid line is the data before the test, and the broken line is the data after the test.

  FIG. 6 shows that the film obtained by curing the composition of the present invention maintains high transparency even after being held at a high temperature for a long time.

Comparative Example 4
The cured film obtained by curing the curable composition prepared in Comparative Example 1 was measured for light transmittance before and after a high temperature long term retention test (160 ° C., retained for 7 days). The results are shown in FIG. The solid line is the data before the test, and the broken line is the data after the test.

  From FIG. 7, it can be seen that the transparency of a film obtained by curing a composition using a polymer containing a urethane bond is lowered when it is kept at a high temperature for a long period of time.

Claims (9)

(A) Formula (1):
Wherein X ¹ and X ² are the same or different and are a fluorine atom or a hydrogen atom; X ³ is a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or a trifluoromethyl group; X ⁴ and X ⁵ are the same or Differently, a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; a is an integer of 1 to 3; R ¹ is a linear or branched alkyl group containing at least one hydroxyl group, a fluoroalkyl group, a peroxy group; A hydroxyl group-containing fluoropolymer comprising a hydroxyl group-containing structural unit (1) represented by a fluoroalkyl group (which may contain an ether bond and / or an ester bond in the chain);
(B) A heat resistant transparent solution in which an unsaturated group-containing fluoropolymer (I) obtained by subjecting an unsaturated carboxylic acid or its acid halide to an esterification reaction is dissolved in an acrylic monomer (II) Solvent-free curable fluorine-containing resin composition. The hydroxyl group-containing fluoropolymer (a) is represented by the formula (1a):
(Wherein Z is a hydrocarbon group containing at least one monovalent carbon-carbon double bond, Y is a divalent organic group or a single bond; m is an integer of 0 to 5). The composition of claim 1 comprising ether structural units. The unsaturated carboxylic acid (b) has the formula (4):
^{CX 11 X 12 = CX 13 -} (R 3) c -COM
Wherein X ¹¹ and X ¹² are the same or different and are a fluorine atom or a hydrogen atom; X ¹³ is a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or a trifluoromethyl group; M is —OH or a halogen atom; ^3. The resin composition according to claim 1, wherein ³ is a divalent organic group; c is a compound represented by 0 or 1). (A) Formula (1):
Wherein X ¹ and X ² are the same or different and are a fluorine atom or a hydrogen atom; X ³ is a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or a trifluoromethyl group; X ⁴ and X ⁵ are the same or Differently, a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; a is an integer of 1 to 3; R ¹ is a linear or branched alkyl group containing at least one hydroxyl group, a fluoroalkyl group, a peroxy group; A hydroxyl group-containing fluoropolymer comprising a hydroxyl group-containing structural unit (1) represented by a fluoroalkyl group (which may contain an ether bond and / or an ester bond in the chain); and (b) unsaturated After the esterification reaction of carboxylic acid or its acid halide, impurities are removed by purification, and the unsaturated group-containing fluoropolymer obtained by drying under conditions of 60 ° C. or lower ( ) The method for producing a acrylic monomer (II) can be dissolved in and said heat-resistant transparent solventless curable fluorine-containing resin composition. The hydroxyl group-containing fluoropolymer (a) is represented by the formula (1a):
(Wherein Z is a hydrocarbon group containing at least one monovalent carbon-carbon double bond, Y is a divalent organic group or a single bond; m is an integer of 0 to 5). The manufacturing method of Claim 4 containing an ether structural unit. The unsaturated carboxylic acid (b) has the formula (4):
^{CX 11 X 12 = CX 13 -} (R 3) c -COM
Wherein X ¹¹ and X ¹² are the same or different and are a fluorine atom or a hydrogen atom; X ¹³ is a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or a trifluoromethyl group; M is —OH or a halogen atom; 6. The production method according to claim 4, wherein ³ is a divalent organic group; c is a compound represented by 0 or 1). Hardened | cured material obtained by hardening | curing the resin composition in any one of Claims 1-3. The hardened | cured material of Claim 7 whose light transmittance of the area | region of wavelength 400-800 nm is 80% or more. The cured product according to claim 7, which is a sealing member for an optical element.