JP2882737B2 - Method for producing fluoropolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a uniform and transparent fluorine-containing graft polymer, and more particularly to a method for producing a polymer having a hydroxyl group in a main chain or a graft chain, which can be cured with a polyvalent isocyanate or melamine resin. The present invention relates to a method for producing a possible fluorine-containing graft polymer.

[0002]

2. Description of the Related Art Conventionally, a coating material using a fluoropolymer has been widely applied to fields such as chemical industry, construction, food, and machinery because of its excellent weather resistance, heat resistance and chemical resistance. . Particularly in recent years, there has been a paint using a solvent-soluble fluoropolymer with improved workability, which has been spotlighted. These increase the solubility of the fluoropolymer in organic solvents, allow it to be dissolved in common coating solvents, and can be cured by introducing reactive groups such as hydroxyl groups into the fluoropolymer. It is a paint that was a good type.

For example, Japanese Patent Application Laid-Open No. 61-57609 and Japanese Patent Application Laid-Open
The coating polymer disclosed in No. 289874 is a copolymer of a fluorinated olefin and a hydrocarbon monomer containing no fluorine in order to improve the solubility of the fluorine-containing polymer in an organic solvent and the like. By introducing a hydroxyl group into the resin, it can be cured even at room temperature. Paints using such fluoropolymers are used in general construction, automobiles, road civil engineering, and metal fields, and are often used as long-term maintenance-free paints utilizing their weather resistance and chemical resistance.

[0004]

However, recently, the problem that the paint based on these fluoropolymers has poor stain resistance has been highlighted. That is, compared to conventional alkyd resins, urethane resins, epoxy resins, polyester resins, and general-purpose paints such as acrylic resins, contaminants are more likely to adhere in natural exposure tests and artificial contamination tests, and the adhered contaminants are less likely to be removed. Phenomenon has been found. Therefore, in the fluorine-containing paint, improvement of stain resistance is an important issue for maintaining the appearance of the coating film.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies with the aim of improving the stain resistance while maintaining the basic physical properties such as the weather resistance of the fluorine-containing paint. A solvent-soluble fluorinated olefin containing-is reacted with an unsaturated isocyanate to a fluorinated polymer which is a fatty acid vinyl ester copolymer to obtain an unsaturated group-containing fluorinated polymer having a carbon-carbon double bond in a side chain. In the method for producing a hydroxyl group-containing fluorine-containing graft polymer by radically polymerizing a monomer having a carbon-carbon double bond in the presence of the solution, the first step is to produce a solution. Identify the fluoropolymer and the monomer to be grafted, and further optimize the raw materials and polymerization conditions such as the amount of unsaturated bond introduced into the side chain of the fluoropolymer. , Uniform and transparent graft polymer solution obtained, and stain resistance of improved cured film found that was obtained led to the present invention.

That is, the present invention relates to a method for producing an unsaturated group-containing fluoropolymer by reacting a hydroxyl group-containing fluoropolymer with 0.1 to 1 equivalent of an unsaturated isocyanate per 1 equivalent of the hydroxyl group. The first step is to prepare a solution, and then the monomer in the presence of the solution
The second step is to polymerize (2) to produce a graft polymer.
A method for producing a hydroxyl group-containing fluorinated graft polymer, comprising the step of: containing 50 to 95% by weight of the unsaturated group-containing fluorinated polymer. A method for producing a polymer, in particular, a fluorinated polymer containing a hydroxyl group has a number average molecular weight (polystyrene equivalent) of 1,000 to 20,000, chlorotrifluoroethylene , a fatty acid vinyl ester or a fatty acid isopropenyl ester, and ethylene glycol.
Monomer consisting essentially of coal monoallyl ether
A method for producing a hydroxyl group-containing fluorine-containing graft polymer , which is a copolymer obtained by polymerizing (1), wherein the copolymer contains a carboxyl group-containing monomer as an essential component, if necessary. It is.

A method for introducing an unsaturated group into a polymer having a reactive group, for example, by reacting a polymer having a hydroxyl group with an unsaturated isocyanate to obtain a polymer having an unsaturated side chain. The method is disclosed in JP-A-59-230019, and J. Coating Tech. Vol. 55 (No. 703) 55-
61 (1983).

On the other hand, as an application of this method to a fluorine-containing polymer, there is provided a method wherein an unsaturated isocyanate is reacted with a fluorinated olefin-vinyl ether-hydroxyl group-containing vinyl ether copolymer to obtain an unsaturated side chain-containing fluorine polymer. Is disclosed in JP-A-62-25104,
A method for introducing an unsaturated side chain by reacting a fluorinated polymer having a carboxyl group with glycidyl methacrylate is disclosed in Examples of JP-A-62-25103.

It is also known that a fluorine-containing graft polymer can be obtained by polymerizing a monomer in the presence of the thus obtained unsaturated group-containing fluorine-containing polymer.

Generally, graft polymerization is an effective means for improving the compatibility of two or more kinds of polymers. When the above-mentioned method is used, there is no compatibility between the fluorine-containing polymer and the polymer grafted thereto. In some cases, it is known that some degree of compatibility is exhibited. However, in general, the compatibility is good in the region where the content of the fluoropolymer is small, but the compatibility is poor in the region where the content of the fluoropolymer is high where the high performance of the fluororesin paint should be utilized. It was not possible to obtain a homogeneous and transparent graft polymer solution having good compatibility to obtain a coating film. For example, when the fluorinated polymer containing a hydroxyl group as described in the above-mentioned patent specification is a fluorinated olefin-vinyl ether-hydroxyl group-containing vinyl ether copolymer, complete compatibility is obtained. In many cases, a non-uniform graft polymer solution was obtained, and phase separation of a cured coating film occurred, which was not satisfactory as a coating material.

The hydroxyl group of the hydroxyl group-containing fluorinated graft polymer of the present invention can be introduced into the side chain of the fluorinated olefin-fatty acid vinyl ester copolymer as an unreacted residual group. Can be introduced into a graft chain by using a hydroxyl group-containing monomer in the graft polymerization of the above.

Hereinafter, the present invention will be described in more detail. The monomer unit of the fluorine-containing polymer containing a hydroxyl group used in the present invention is particularly important, and a uniform transparent graft polymer solution can be obtained by the composition of the present invention. The monomer
(1) as chlorotrifluoroethylene , fatty acid vinyl ester or fatty acid isopropenyl ester,
Ethylene glycol monoallyl ether is an essential component.

Specifically, chlorotrifluoroethylene
Is tetrafluoroethylene, dichlorodifluoroethyl
Len, hexafluoropropylene, vinylidenefluora
Id, vinyl fluoride, hexafluoroisobute
Of perfluoroalkyl vinyl ethers
Olefins, and mixtures with these are also used
You. Examples of the fatty acid vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate (versatic pentanate), vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, and vinyl palmitate. , Vinyl stearate, vinyl versatate 9 and vinyl versatate 10.

The fatty acid isopropenyl esters include:
For example, isopropenyl acetate, isopropenyl propionate, isopropenyl butyrate, isopropenyl pivalate (versatic pentaacid), isopropenyl caproate, isopropenyl caprylate, isopropenyl caprate,
Isopropenyl laurate, isopropenyl myristate, isopropenyl palmitate, isopropenyl stearate, isopropenyl versatate 9 and isopropenyl versatate 10 are exemplified.

The structural formula of the above-mentioned fatty acid vinyl ester or fatty acid isopropenyl has a general formula

[0016]

Embedded image

(R ₁ is H or CH ₃ , R ₂ , R ₃ , R
₄ is H or CnH2n + 1, n is an integer of 1-10. ) And mixtures thereof are also used. ethylene glycol
Monoallyl ether is hydroxyethyl allyl ether
, Hydroxypropyl allyl ether, hydroxyi
Sopropyl allyl ether, hydroxybutyl allyl ether
-Tel, hydroxyisobutyl allyl ether, hydro
Xy-t-butyl allyl ether, hydroxypentyl
Allyl ether, hydroxyneopentyl allyl ether
Hydroxyalkyl allyl ethers such as
Lactone-modified allyl acrylate as a reaction product with coutones
Ter etc. and diethylene glycol, triethylene glycol
Polyethylene such as coal and tetraethylene glycol
Recall monoallyl ethers and polypropylene glycol
Includes hydroxyl groups such as monoallyl ethers of coal
Mixtures with allyl ethers are also used.

The hydroxyl group-containing fluoropolymer of the present invention is a copolymer produced from monomers selected from the above three groups of monomers.
Also included are polymers in which a carboxyl group-containing monomer such as methacrylic acid, crotonic acid, vinyl acetic acid, undecylenic acid or a reaction product of hydroxylalkyl allyl ether and succinic anhydride is added as a copolymerization component.

[0019] The composition of the fluorocopolymer is not particularly limited, preferably chlorotrifluoroethylene, fatty acid vinyl ester or a fatty acid isopropenyl ester, et
Tylene glycol monoallyl ether , and the content of the unit based on the carboxyl group-containing monomer is 25% each.
~ 75 mol%, 10-70 mol%, 2-40 mol%, and 0-20
Mol%.

The molecular weight of the fluorine-containing copolymer is suitably from 1,000 to 30,000, preferably from 1,000 to 20,000, as the number average molecular weight (in terms of polystyrene). When the molecular weight is more than 30,000, problems such as gelation of the solution in the graft polymerization, and a problem that the graft polymer solution becomes viscous and the solid content concentration cannot be increased.

As the unsaturated isocyanate to be reacted with the fluorinated copolymer, acrylate or methacrylate having an isocyanate alkyl group is suitable. For example, 2-isocyanate ethyl acrylate, 2-isocyanate ethyl methacrylate, 4-isocyanate butyl acrylate, 4-isocyanate butyl methacrylate and the like can be mentioned.

Further, a reaction product obtained by reacting 1 to 1.8 moles of an unsaturated monoalcohol with respect to 1 mole of diisocyanate is used as it is. When the amount of the unsaturated monoalcohol is less than 1 mol, unreacted diisocyanate remains in the product and gelation or precipitation occurs during the reaction with the hydroxyl group-containing fluorinated copolymer. When the amount is more than 1.8 mol, in addition to the unsaturated monoisocyanate to be produced, a compound having an unsaturated group at each end via a urethane bond increases, and gelation occurs in the subsequent graft polymerization. Examples of the diisocyanate include 2,4-tolylene diisocyanate, a mixed isocyanate of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, P, P'-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, and para-isocyanate. Examples include phenylene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated xylylene diisocyanate. Examples of the unsaturated monoalcohol include acryloyl or methacryloyl groups such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, and 4-hydroxybutyl methacrylate. And allyl alcohols having an allyl group such as allyl alcohol, allyl cellosolve and trimethylpropane diallyl ether.

The reactive group ratio between the hydroxyl group-containing fluorine-containing polymer and the unsaturated monoisocyanate is determined as follows.
It is preferred that the isocyanate group of the unsaturated monoisocyanate is in the range of 0.1 to 1 mol per 1 mol. At 0.1 mol or less, the unsaturated bond concentration in the unsaturated group-containing fluoropolymer is low, so the efficiency in the graft polymerization is low, and the compatibility between the unsaturated group-containing fluoropolymer and the graft chain is poor and uniform and transparent. No solution is obtained. If it is 1 mol or more, unreacted unsaturated monoisocyanate remains, so that gelation or precipitation of the solution occurs due to the influence of moisture in the graft polymerization. In this case, the use of a monomer having a reactive group that reacts with an isocyanate group in the graft polymerization, for example, a monomer having a hydroxyl group is limited.

The graft polymer is produced by polymerizing the monomer (2) in the presence of the above unsaturated group-containing fluoropolymer solution. As the monomer (2) to be graft-polymerized, a monomer containing no fluorine is used from the viewpoint of economy. As the monomer (2) , acrylates, methacrylates, chlorine-based olefins, hydrocarbon-based olefins, vinyl esters, and other radically polymerizable monomers are all applicable, but a uniform and transparent graft polymer solution is obtained. From the viewpoint, the use of a monomer having an acryloyl group and a methacryloyl group is preferred. For example, acrylic acid, acrylic acid metal salt, ammonium acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate,
t-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, isodecyl acrylate, lauryl acrylate,
Tridecyl acrylate, stearyl acrylate, benzyl acrylate, isobornyl acrylate, phenoxyethyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, carbitol acrylate, 2-methoxyethyl acrylate, 2-ethoxyethoxyethyl acrylate, 2-butoxyethyl acrylate, Methoxy diethylene glycol acrylate, ethoxy diethylene glycol acrylate, methoxy triethylene glycol acrylate, methoxy polyethylene glycol acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, 2-chloroethyl acrylate, 2-hydroxyethyl acrylate, diethylene glycol monoacrylate, triethylene Glycol monoacrylate,
Neopentyl glycol monoacrylate, 3-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 1,6 hexanediol monoacrylate, polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, trimethylolpropane monoacrylate,
Pentaerythritol monoacrylate, acrylamide, 2-aminoethyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate,
Glycidyl acrylate, 2-chloro-2-hydroxypropyl acrylate, 2-hydroxy-3-acryloxypropylammonium chloride, diphenyl-2-acryloyloxyethyl phosphate, 2-acryloxyethyl acid phosphate, 3-chloro-2-acid phosphate Foxpropyl acrylate, methacrylic acid, metal methacrylate, ammonium methacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, benzyl methacrylate Relate, isobornyl methacrylate, phenoxyethyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, carbitol methacrylate,
2-methoxyethyl methacrylate, 2-ethoxyethoxyethyl methacrylate, 2-butoxyethyl methacrylate, methoxydiethylene glycol methacrylate, ethoxydiethylene glycol methacrylate, methoxytriethylene glycol methacrylate, methoxypolyethylene glycol methacrylate, dicyclopentenyl methacrylate, dicyclopentenyloxyethyl methacrylate, 2-chloroethyl methacrylate, 2-hydroxyethyl methacrylate, diethylene glycol monomethacrylate, triethylene glycol monomethacrylate, neopentyl glycol monomethacrylate, 3-hydroxypropyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 1,6- Hexanedi Over mono methacrylate,
Polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, methacrylamide, 2-aminoethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, glycidyl methacrylate, 2-chloro-2-hydroxypropyl Acrylates and methacrylates such as methacrylate, 2-hydroxy-3-methacryloxypropylammonium chloride, diphenyl-2-methacryloyloxyethyl phosphate, 2-methacryloxyethyl acid phosphate, 3-chloro-2-acidphosphoxypropyl methacrylate By single radical polymerization or two or more types of radical polymerization To obtain a polymer.

The content of the unsaturated group-containing fluoropolymer in the graft polymer is preferably from 50 to 95% by weight. If the content is less than 50% by weight, the fluorine content decreases and the weather resistance decreases.
If it is more than 10% by weight, the effect of compatibility by grafting does not appear and a smooth coating film cannot be obtained, which is not preferable. Further, the number average molecular weight of the graft polymer is preferably 100,000 or less. When the number average molecular weight is 100,000 or more, it is difficult to adjust the viscosity and the solid content of the paint, which is not preferable.

The graft polymer of the present invention is prepared by blending a diisocyanate, a blocked isocyanate, melamine, etc. as a crosslinking agent (curing agent), a solvent, a pigment, a dispersion stabilizer, a leveling agent, an ultraviolet absorber, a light stabilizer and the like. Used as a curable paint.

The coating composition containing the hydroxyl group-containing fluorine-containing graft polymer of the present invention has the characteristics of a coating composition using a conventional solvent-soluble fluororesin, as well as stain resistance and adhesion to a substrate. In addition, by selecting a graft polymer chain, it is possible to prepare from a soft coating film to a hard coating film as compared with the above-mentioned conventional paint.

It is suitable for general architectural purposes, automobiles, machinery and equipment, plastics, and metal coatings such as pre-coated metals, but also has the advantage of being economically superior to conventional fluorine-based paints.

Hereinafter, the present invention will be described by reference examples, examples, and comparative examples, but is not limited thereto.

[0030]

【Example】

[Reference Example 1] SU with an electromagnetic stirrer and a capacity of 30 liters
4.63 kg of xylene and 1.60 vinyl acetate in an S autoclave
Kg, versatic vinyl 9-acid 3.43 kg, ethylene glycol monoallyl ether 1.68 kg, vinyl acetic acid 0.10 kg, t-
After charging 0.09 kg of butyl peroxypivalate and 0.13 kg of celite, repeating degassing and nitrogen substitution three times, charging 6.43 kg of chlorotrifluoroethylene, polymerization was carried out at 55 ° C. for 20 hours, and the polymerization yield was 67.6%. A polymer solution (varnish) was obtained.

Washing, concentration and concentration adjustment of the varnish,
Filtration is performed, and the solid content (residue after heating at 130 ° C.
same as below. ) A xylene solution with a concentration of 60% was obtained. The OH value of the polymer in the varnish was 78 mgKOH / g, and the acid value was 7 mgKOH / g. In addition, the glass transition point of the polymer (measuring the resin Tg attached to the glass fiber using a torsional free damping type viscoelasticity measuring instrument)
At 51 ° C., the number average molecular weight (measured by gel permeation, converted to polystyrene) was 7,100, and the weight average molecular weight was 14,500.

Reference Example 2 In the same manner as in Reference Example 1, n-butyl acetate (6.61 kg), vinyl pivalate (1.98 kg) were placed in a 30-liter SUS autoclave equipped with a magnetic stirrer.
Versatic vinyl 9 acid 2.85 kg, ethylene glycol monoallyl ether 0.81 kg, undecylenic acid 0.16 kg, t-
Butyl peroxypivalate 0.08Kg, sodium carbonate 0.
After charging 03 kg and repeating degassing and nitrogen replacement three times,
Charge 5.65 Kg of chlorotrifluoroethylene and add 20 at 55 ° C.
Polymerization was carried out for a time to obtain a polymer solution with a polymerization yield of 80.5%.

The varnish was adjusted in concentration and filtered to obtain an n-butyl acetate solution having a solid content of 55%. The OH value of the polymer in the varnish was 46 mgKOH / g, and the acid value was 7 mgKOH / g. The polymer had a glass transition point of 59 ° C. and a number average molecular weight of 14,500.

Reference Example 3 In the same manner as in Reference Example 1, 12.04 kg of xylene, 3.05 kg of vinyl pivalate, 4.39 kg of vinyl versatate, 4.39 kg of ethylene glycol monohydrate were placed in a 50-liter SUS autoclave equipped with a magnetic stirrer. 2.76 kg of allyl ether, t-butyl peroxypivalate
After charging 0.14Kg and 0.06Kg of sodium carbonate and repeating degassing and nitrogen replacement three times, chlorotrifluoroethylene
Charged 9.71Kg, polymerized at 55 ° C for 20 hours, polymerization yield
A polymer solution was obtained at 81.5%.

The varnish was adjusted in concentration and filtered to obtain a xylene solution having a solid content of 65%. The OH value of the polymer in the varnish was 80 mgKOH / g. Further, the glass transition point of the polymer was 49 ° C., and the number average molecular weight was 5,200.

Example 1 In a 1-liter separable flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser, 666.4 g of the varnish of Reference Example 1 and 0.8 g of dibutyltin dilaurate were charged and the temperature was raised to 60 ° C. Warmed. Thereafter, 21.6 g of 2-isocyanateethyl methacrylate containing 200 ppm of benzoquinone under a stream of dry air while stirring.
Was gradually added dropwise (OH / NCO molar ratio = 1 / 0.15). After holding for 2 hours after completion of the dropwise addition, an infrared absorption spectrum of the reaction solution was measured. The absorption of the isocyanate group at a wavelength of 2,260 cm ^-1 completely disappeared, confirming that the reaction between the hydroxyl group and the isocyanate group proceeded quantitatively.

Next, 241 g of the above reaction solution (147 g of solid content), 186.7 g of xylene, 70 g of isobornyl methacrylate, 6 g of isobutyl methacrylate were placed in a 1-liter separable flask equipped with a stirrer, a thermometer and a reflux condenser.
1.6 g, 8.4 g of acrylic acid, and 2.8 g of azobisisobutyronitrile as a radical initiator were charged and graft polymerization was performed at 70 ° C. for 6 hours under a nitrogen stream while stirring.

The resulting varnish was a homogeneous solution, the solid content of the varnish was 51%, and the OH value of the polymer in the varnish was 38 mg KO.
The H / g and the acid value were 32 mgKOH / g. A polymer was precipitated by adding n-hexane to the varnish, dried and then redissolved in xylene to measure the molecular weight. Number average molecular weight (polystyrene equivalent) 15,000, Weight average molecular weight (polystyrene equivalent) 90,0
00, which was confirmed to be a graft polymer.

The glass transition point of the resin (inflection point of the elastic modulus measured by applying a varnish to the glass fiber and drying and then changing the temperature after drying) was 72 ° C. by the torsional free attenuation type viscoelasticity measurement. Example 2 545.4 g of the varnish of Reference Example 2 was charged into a 1-liter separable flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser, and the temperature was raised to 60 ° C. Then, while stirring, 2-isocyanatoethyl methacrylate containing 200 ppm of benzoquinone under a stream of dry air
20.7 g was gradually added dropwise (OH / NCO molar ratio = 1 / 0.3).

After holding for 4 hours after the completion of dropping, the infrared absorption spectrum of the reaction solution was measured. The absorption of the isocyanate group at a wavelength of 2,260 cm ^-1 completely disappeared, confirming that the reaction between the hydroxyl group and the isocyanate group proceeded quantitatively.

Next, 472.2 g (solid content: 267.2 g) of the reaction solution and 51.1 g of n-butyl acetate were placed in a 1-liter separable flask equipped with a stirrer, a thermometer and a reflux condenser.
g, 37.5 g of methyl methacrylate, 25 g of isobutyl methacrylate, and 3.1 g of azobisisobutyronitrile as a radical initiator under a nitrogen stream while stirring and charging.
Graft polymerization was performed at 70 ° C. for 7 hours.

The resulting varnish was a homogeneous solution, the solid content of the varnish was 55%, and the OH value of the polymer in the varnish was 31 mg KO.
H / g and the acid value were 5 mgKOH / g. N-Hexane was added to the varnish to precipitate a polymer, which was dried and then redissolved in tetrahydrofuran to measure the molecular weight. The number average molecular weight (in terms of polystyrene) was 35,000, and it was confirmed that the polymer was a graft polymer.

The glass transition point of the resin (inflection point of the elastic modulus measured by applying a varnish to a glass fiber and drying and then changing the temperature) by measurement of viscoelasticity of torsional free attenuation type was 64 ° C. Example 3 Into a 1-liter separable flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser, 615.2 g of the varnish of Reference Example 3 was charged and the temperature was raised to 60 ° C. Then, while stirring, 2-isocyanatoethyl methacrylate containing 200 ppm of benzoquinone under a stream of dry air
122 g was slowly added dropwise (OH / NCO molar ratio = 1 / 0.9).

After holding for 7 hours after the completion of dropping, the infrared absorption spectrum of the reaction solution was measured. The absorption of the isocyanate group at a wavelength of 2,260 cm ^-1 completely disappeared, confirming that the reaction between the hydroxyl group and the isocyanate group proceeded quantitatively.

Next, 147.6 g (solid content: 104.4 g) of the above reaction solution, 362.7 g of xylene, 74.6 g of methyl methacrylate, and 74.6 g of ethyl acrylate were placed in a 1-liter separable flask equipped with a stirrer, a thermometer, and a reflux condenser.
g, 37.3 g of 2-hydroxyethyl methacrylate and 2.6 g of azobisisobutyronitrile as a radical initiator, and graft polymerization was carried out at 80 ° C. for 10 hours under a nitrogen stream while stirring.

The resulting varnish was a homogeneous solution, the solid content of the varnish was 45%, and the OH value of the polymer in the varnish was 54 mg KO.
H / g and the acid value were 0 mgKOH / g. A polymer was precipitated by adding n-hexane to the varnish, dried and then redissolved in xylene to measure the molecular weight. The polymer had a number average molecular weight (polystyrene equivalent) of 48,000, and was confirmed to be a graft polymer.

The glass transition point of the resin (inflection point of the elastic modulus measured by applying a varnish to a glass fiber and drying and changing the temperature after drying) was 56 ° C. according to the torsional free damping type viscoelasticity measurement. Example 4 The varnishes of Examples 1 to 3 were mixed with titanium oxide (white pigment), and the coating compositions of Formulations 1 to 3 were further mixed with an isocyanate-based curing agent, Coronate HX, and diluted with a thinner to 70 mm × 150 mm × The mixture was sprayed onto a 0.5 mm bonderite steel sheet and cured at room temperature for about 24 hours. Various measurements were performed on the obtained coating film. The composition of the coating composition and the properties of the cured coating film are shown in Table 1.

COMPARATIVE EXAMPLE The varnishes of Reference Examples 1 to 3 were mixed with titanium oxide (white pigment), and further mixed with an isocyanate-based curing agent Coronate HX. 150mm × 0.5mm
At room temperature for about 24 hours. Various measurements were performed on the obtained coating film. The composition of the coating composition and the properties of the cured coating film are shown in Table 1.

[0049]

[Table 1]

[0050]

The paint comprising the hydroxyl group-containing fluorinated graft polymer obtained by the method of the present invention is:
As is clear from the comparison between the examples and the reference examples, remarkable improvement in stain resistance is observed while maintaining excellent characteristics such as weather resistance of the fluorine-based resin coating.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08F 214/24 C08F 214/24 C08G 18/62 C08G 18/62 18/81 18/81 (C08F 214/24 218: 02 216: 20) (72) Inventor Takashi Minoura 3-20 Nishiki-cho, Chiyoda-ku, Tokyo Showa Polymer Co., Ltd. (72) Inventor Takashi Yasumura 2805 Imafukunakadai, Kawagoe-shi, Saitama Tokyo Research Laboratory of Central Glass Co., Ltd. (72 ) Inventor Kazuhiko Maeda 2805, Imafukunakadai, Kawagoe-shi, Saitama Central Research Laboratory Tokyo Research Laboratory (56) References JP-A-61-57609 (JP, A) JP-A-62-25104 (JP, A) JP-A-62-295914 (JP, A) JP-A-2-189317 (JP, A) JP-A-4-39313 (JP, A) JP-A-61-275364 (JP, A) JP-A-62-27767 (JP, A) JP, A) JP-A-61-296073 ( P, A) JP Akira 63-68604 (JP, A) JP flat 1-113416 (JP, A) JP flat 5-117480 (JP, A) (58 ) investigated the field (Int.Cl. ^6, (DB name) C08F 290/00-290/14 C09D 1/00-201/10

Claims (5)

(57) [Claims] 1. A chlorotrifluoroethylene, fatty acid vinyl ester or a fatty acid isopropenyl ester, ethyl
A simple substance consisting essentially of lenglycol monoallyl ether
The hydroxyl-containing polymer having a number average molecular weight (in terms of polystyrene) of 1,000 to 20,000, obtained by polymerizing the monomer (1), is added in an amount of 0.1 to 1 equivalent of the hydroxyl group.
The first step is to produce a solution of the unsaturated group-containing fluoropolymer by reacting at least one equivalent and at most 1 equivalent of the unsaturated isocyanate, and then polymerizing and grafting the monomer (2) in the presence of the solution. A method for producing a hydroxyl group-containing fluorinated graft polymer, comprising the step of producing a polymer as a second step, comprising 50 to 95% by weight of the unsaturated group-containing fluorinated polymer. For producing a hydroxyl group-containing fluorinated graft polymer. 2. The method for producing a hydroxyl group-containing fluorine-containing graft polymer according to claim 1, wherein the unsaturated isocyanate is a methacrylate or an acrylate having an isocyanate alkyl group. Fluoropolymer comprises wherein hydroxyl groups
The method for producing a hydroxyl group-containing fluorine-containing graft polymer according to claim 1, wherein the copolymer is a copolymer obtained by polymerizing a carboxyl group-containing monomer . 4. The method according to claim 1, wherein the monomer (2) is an acrylic monomer and / or
2. The method for producing a hydroxyl group-containing fluorine-containing graft polymer according to claim 1, wherein the monomer (2) is mainly a methacrylic monomer. 5. A coating film obtained by curing the hydroxyl-containing fluorine-containing graft polymer according to claim 1 at room temperature or by heating using a polyvalent isocyanate compound, a blocked isocyanate compound or a melamine resin as a curing agent. How to get.