JPS61118466A - Fluorine-containing resin coating composition - Google Patents

Abstract

PURPOSE:To provide the titled composition composed of a fluorine-containing resin having urethane bond, F and alpha,beta-ethylenic unsaturated bond in the molecule, and an organic peroxide, giving a coating film having excellent weather- resistance, corrosion-resistance, chemical resistance, etc., and suitable for the protection of various metallic products. CONSTITUTION:The objective composition is composed of (A) a fluorine- containing resin having urethane bond, F, and alpha,beta-ethylenic unsaturated bond in the molecule and (B) an organic peroxide (e.g. benzoyl peroxide). EFFECT:It has excellent solubility in organic diluent, and gives a coating film having excellent gloss, brightness and transparency. USE:Protective coating of plastic article, optical fiber, IC substrate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a fluororesin coating composition that provides a coating film with excellent weather resistance, corrosion resistance, chemical resistance, etc.

[Conventional technology]

Conventionally, the main coating compositions known to be curable with organic peroxides include polyester acrylate resins, epoxy acrylate resins, urethane acrylate resins, polyether acrylate resins, and silicone acrylate resins. .

[Problem that the invention seeks to solve]

In recent years, there has been a demand for longer life of coating films in the field of metal coatings such as curtain walls, pre-coated metals, plastic coatings, etc., but the coating compositions mentioned above have long-term weather resistance, It was difficult to obtain a coating film with excellent corrosion resistance and chemical resistance, and the above requirements were not met.

Therefore, fluororesin-based coating compositions with excellent long-term weather resistance are attracting attention.

However, conventionally known fluororesin coating compositions generally have poor solubility in machine diluents, and the resulting coating films have poor gloss, sharpness, and transparency compared to the conventional coating compositions. It had the disadvantage of being inferior.

Due to these drawbacks, fluororesin coating compositions still do not have sufficient commercial value in the field of coatings, where initial coating appearance and aesthetics are important, and therefore, fluororesin-based coating compositions cannot be said to have sufficient commercial value. Although this was acknowledged, early improvements were requested.

[Means for solving problems]

In view of the current situation as described above, the inventors of the present invention have arrived at the present invention as a result of intensive studies to eliminate the above-mentioned drawbacks.

That is, the present invention relates to a fluororesin coating composition comprising a fluororesin and an organic peroxide, which have a urethane bond, a fluorine atom, and an α,β-ethylenically unsaturated group in the molecule.

The present invention will be explained in detail below.

The fluororesin used in the present invention is produced by reacting a fluorine atom-containing polyol with a diisocyanate compound,
Then, the free isocyanate groups contained in the reaction product are further reacted with acrylate and/or methacrylate having a hydroxyl group. That is, a hydroxyl value of about 30 to 200, a weight average molecular weight of about 1
．． 000 to 50.000 fluorine atom-containing polyol is reacted with a diisocyanate compound in an amount of about 165 to 2.5 equivalents per equivalent of hydroxyl group of the fluorine atom-containing polyol, and the reaction product is added to the resulting reaction product. It can be obtained by mixing and reacting an acrylate and/or methacrylate having a hydroxyl group in an approximately equivalent amount to a free isocyanate group.

The fluorine atom-containing polyol is preferably a copolymer described in JP-A-57-34107. That is, the copolymer contains 40 to 60 mol%, 5 to 45 mol%, 5 to 45 mol%, and 3 to 25 mol% of fluoroolefin, cyclohexyl vinyl ether, alkyl vinyl ether, and hydroxyalkyl vinyl ether as essential components, respectively. proportions, preferably 45-55 mol%, 10-30 mol%, 10
It is contained in a proportion of ~35 mol% and 5-20 mol%.

Too low a fluoroolefin content is not only unfavorable from the viewpoint of weather resistance, but also causes problems in production.

Also, those containing too high a fluoroolefin content are also difficult to manufacture. On the other hand, if the cyclohexyl vinyl ether content is too low, the hardness of the coating film will decrease, and if the alkyl vinyl ether content is too low, the flexibility will decrease, so both are not preferred.

Furthermore, it is particularly important that the composition contains hydroxyalkyl vinyl ether in a proportion within the above range from the viewpoint of improving curability without impairing various useful properties as a paint base.

In other words, if the hydroxyalkyl vinyl ether content is too high, the solubility will change and it will only dissolve in specific substances such as alcohols, and the flexibility of the cured coating will decrease, which is undesirable. If it is too low, the crosslinking density will be low and the solvent resistance of the cured coating will be poor, which is not preferable.

It is preferable to use perhaloolefins, especially chlorotrifluoroethylene or tetrafluoroethylene, as the fluoroolefins that are raw materials for the copolymer, and as the alkyl vinyl ethers, it is preferable to use chlorotrifluoroethylene or tetrafluoroethylene.
It is preferable to use those containing ~8 linear or branched alkyl groups, particularly those in which the alkyl group has 2 to 4 carbon atoms.

The copolymer may contain comonomers other than the above four essential components in an amount not exceeding 30 mol %. Such comonomers include ethylene, propylene,
Olefins such as isobutylene, haloolefins such as vinyl chloride and vinylidene chloride, unsaturated carboxylic acid esters such as methyl methacrylate, vinyl carboxylates such as vinyl acetate and vinyl n-butyrate, fumaric acid, maleic acid,
Examples include unsaturated carboxylic acids such as acrylic acid and methacrylic acid.

The above copolymer is produced by adding a polymerization initiator such as a water-soluble initiator or an oil-soluble initiator or a polymerization initiation source such as ionizing radiation to a monomer mixture in a predetermined proportion in the presence or absence of a polymerization medium. It is produced by causing a copolymerization reaction to occur.

As the copolymer, ie, the fluorine atom-containing polyol, for example, Lumiflon LF100. Lumiflon LF200.
Lumiflon LF210, Lumiflon LF300, Lumiflon LF400 (all brand names manufactured by Asahi Glass Co., Ltd.), etc. are commercially available.

Examples of the diisocyanate compounds include tolylene diisocyanate, diphenyl diisocyanate, p-phenyl diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenyl diisocyanate, hydrogenated xylylene diisocyanate, and the like. Can be mentioned. Particularly suitable are aliphatic or alicyclic diisocyanate compounds which have good weather resistance.

In addition, examples of the acrylate and/or methacrylate having a hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, and 2-hydroxyethyl acrylate.
Examples include hydroxybutyl methacrylate.

Alternatively, the fluororesin used in the present invention can also be obtained by reacting a fluorine atom-containing polyol with an acrylate and/or methacrylate having an isocyanate group.

That is, it is obtained by reacting a fluorine atom-containing polyol with an acrylate and/or methacrylate having 0.3 to 1 equivalent of isocyanate groups per 1 equivalent of hydroxyl group of the polyol.

If the equivalent ratio of isocyanate groups to hydroxyl groups is less than 0.3, the crosslinking density will be low and the cured coating will have poor solvent resistance, while if it exceeds 1, free isocyanate groups will remain, making it unstable as a sealant. Therefore, neither is preferable.

Moreover, the above copolymers can be suitably used as the fluorine atom-containing polyol. Examples of the acrylate and/or methacrylate having an isocyanate group include a reactive composition of an acrylate or methacrylate having water MS and a diisocyanate compound, isocyanate ethyl acrylate, isocyanate ethyl methacrylate, and the like.

The fluorine-containing resin used in the present invention is a resin having a urethane bond, a fluorine atom, and an a, β-ethylenically unsaturated group in the molecule, which is obtained as described above.

The fluororesin coating composition of the present invention contains the fluororesin and organic peroxide as essential components.

Examples of the organic peroxide used in the present invention include benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, hydroxyhexyl peroxide, tertiary butyl peroxide, and cumene hydroperoxide.

The organic peroxide is added in order to cause a crosslinking reaction of the fluororesin, and the amount added is 10% of the fluororesin.
0.1 to 3 parts by weight relative to 0 parts by weight is suitable. Incidentally, if the amount added is less than the above range, the resulting coating film will not have sufficient curability, while if it is too large, the coating film will become brittle, so both are not preferred.

In addition, in the present invention, in order to control the decomposition of the organic peroxide and the curing speed from room temperature curing to baking curing, 3 parts by weight of a reaction accelerator is added to 100 parts by weight of the fluororesin.
It is desirable to use them together in an amount of no more than parts by weight.

As a reaction accelerator, lauryl mercaptan, diphenyl sulfide, cobalt naphthenate, cobalt octoate, manganese naphthenate, vanadyl octoate, copper naphthenate, calcium naphthenate, barium naphthenate, zinc naphthenate, zirconium naphthenate, dimethylaniline. , jetanol aniline, and the like.

The fluorine-containing resin coating composition of the present invention may further contain an appropriate reactive diluent. Compounds having radically polymerizable double bonds can be used as reactive diluents, but monoacrylates,
Monomethacrylate, polyacrylate and polymethacrylate are preferred. Specifically, cyclohexyl acrylate, cyclohexyl methacrylate, benzyl acrylate, benzyl methacrylate, carpitol acrylate, carpitol methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, Ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, l,6-hexanediol diacrylate , 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol triacrylate Examples include methacrylate, tris(2-acryloxyethyl)isocyanurate, and the like.

These reactive diluents do not necessarily need to be included, but
Since the fluorine-containing resin generally has a high viscosity, it is added in an amount of 150 parts by weight or less, preferably 10 to 50 parts by weight, per 100 parts by weight of the fluororesin in consideration of painting workability and the like.

The fluorine-containing resin coating composition of the present invention includes various other pigments as required: 9r solvent; modifiers such as epoxy acrylate, urethane acrylate, polyester acrylate, silicone resin, and polyamide resin; silane cuffing agent, titanium coupling agent; It is also possible to incorporate additives such as antifoaming agents, antifoaming agents, and leveling agents.

〔Effect of the invention〕

As explained above, the fluorine-containing resin coating composition of the present invention has the following advantages compared to conventionally known organic peroxide-curable coating compositions:
It has excellent long-term weather resistance, corrosion resistance, chemical resistance, etc., and also has poor solubility in organic diluents, which is a drawback of conventionally known fluorine-containing resin coating compositions, and the gloss, sharpness, and transparency of the resulting coating film. This is an epoch-making product that eliminates the disadvantages of

Therefore, the fluorine-containing resin coating composition of the present invention exhibits excellent properties as a protective coating for various metal products, plastic products, etc., and as a protective coating for optical fibers, IC boards, etc.

Hereinafter, the present invention will be explained in more detail with reference to Examples. In the examples, "parts" and "%" are based on weight.

Preparation of fluorine-containing resin liquid A> In a reaction apparatus equipped with a stirrer and a reflux condenser, a fluorine atom-containing polyol [Lumiflon LF200 (trade name, manufactured by Asahi Glass Co., Ltd.); solvent Kijirol, non-volatile content 50%, hydroxyl value 5
2 (in terms of solid content)) and 17 parts of hexamethylene diisocyanate were charged and reacted at 60°C for 3 hours. Then, 12 parts of 2-hydroxyethyl acrylate was added and reacted at 70°C for 2 hours. A fluorine-containing resin liquid A having a urethane bond, a fluorine atom, and an acrylate group therein was prepared.

<Preparation of fluorine-containing resin liquid B> A fluorine atom-containing polyol [
Lumiflon LF210 (trade name manufactured by Asahi Glass Co., Ltd.); Solvent Kijirol, non-volatile content 50%, hydroxyl value 100 (solid content equivalent) 1300 parts and isocyanate ethyl methacrylate 4
0 part was charged and reacted at 60° C. for 3 hours to prepare a fluorine-containing resin liquid B having a urethane bond, a fluorine atom, and a methacrylic group in the molecule.

<Preparation of fluorine-containing resin liquid C> Isophorone diisocyanate 5 was placed in the same reaction apparatus as above.
1 part was heated to 60°C, 33 parts of β-hydroxypropyl acrylate was added dropwise over 1 hour, and then 3 parts of
Time reacts. Next, 300 parts of a fluorine-containing polyol [Lumiflon LF210] was added and reacted at 70°C for 2 hours to prepare a fluorine-containing resin liquid C having a urethane bond, a fluorine atom, and an acrylate group in the molecule.

<Preparation of urethane acrylate resin liquid> In the same reaction apparatus as above, 250 parts of polypropylene glycol with a number average molecular weight of 1000 and 84 parts of hexamethylene diisocyanate were added.
After reacting at 70°C for 2 hours, 2-
Add 65 parts of hydroxyethyl methacrylate,
C. for 2 hours to prepare a urethane acrylate resin liquid.

Preparation of acrylated polyester resin liquid> In a reaction apparatus similar to the above, a polyester polyol (number average Molecular weight 5OO1 hydroxyl value 100)
67.5 parts of acrylic acid, 16.2 parts of acrylic acid, and 0.4 parts of methanesulfonic acid were charged and reacted at 95° C. for 8 hours to prepare an acrylated polyester resin liquid.

Examples 1 to 5 and Comparative Examples 1 to 2 A coating composition (unit: part) shown in Table 1 was applied to a 0.5 mm thick aluminum plate that had been subjected to chromic acid chemical conversion treatment using a knife coater to a film thickness of 25 μm. It was applied and dried at room temperature for one week.

A coating film performance test was conducted on the obtained coating film, and the results are shown in the lower column of Table 1.

As is clear from Table 1, the fluorine-containing resin coating composition of the present invention has a high initial gloss similar to that of the conventional coating compositions of Comparative Examples 1 and 2, and even after the accelerated weathering test. The rate of decline was small, and the weather resistance was extremely superior compared to conventional coating compositions. It also had excellent refractive properties, alkali resistance, acid resistance, and rubbing resistance.

Example 6 The coating composition shown in Table 1 was applied in the same manner as in Example 1 except that the curing method was baked at 120°C for 30 minutes, and the obtained coating film performance test results are shown in Table 1. Shown in the bottom column.

As is clear from Table 1, the resin-containing resin coating composition of the present invention was extremely superior in weather resistance, alkali resistance, and acidity compared to conventional coating compositions.

Claims (1)

[Claims] A fluororesin coating composition comprising a fluororesin and an organic peroxide, which has a urethane bond, a fluorine atom, and an α,β-ethylenically unsaturated group in the molecule.