JPS63196667A - Coating material composition - Google Patents

Abstract

PURPOSE:To provide a coating material compsn. which gives a coating film having excellent hardness, adhesion and resistance to wear and water, by blending a specified polyfunctional monomer with a bifunctional monomer, a fluorinated (meth)acrylate compd. and a polymn. initiator in a specified weight ratio. CONSTITUTION:10-70wt.% polyfunctional monomer (A) having at least three (meth)acryloyl groups per molecule and an MW not higher than 900 (e.g., trimethylolpropane triacrylate) is mixed with 10-70wt.% bifunctional monomer (B) of formula I [wherein Y1 and Y2 are each (meth)acryloyl], 10-60wt.% fluorinated (meth)acrylate compd. (C) of formula II [wherein Y3 is (meth) acryloyl; Rf is a 1-20C fluorinated alkyl] (e.g., 2,2,2-trifluoroethyl acrylate) and a polymn. initiator (D) (e.g., benzoin) in such a proportion that the total amount of the components A, B and C is 100wt.%, thus obtaining a coating material compsn.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention provides excellent adhesion to coated materials such as synthetic resin molded products, other metal plates, and wood, as well as abrasion resistance and water resistance, by irradiation with ultraviolet rays. The present invention relates to a coating material composition capable of forming a highly hard crosslinked cured coating with excellent properties.

[Conventional technology]

Synthetic resin molded products made from polycarbonate resin, polymethyl methacrylate resin, etc. lack surface wear resistance, so the surface may be damaged by contact with other hard objects, friction, or scratches. Since damage occurring on the surface of the file 11 significantly reduces its commercial value, there is a strong demand for improving the wear resistance of the surface of the molded product.

In order to improve these drawbacks of synthetic resin molded products, it is known that the surface of the molded product is coated with an appropriate resin. Curable resins or polyfunctional monomers or oligomers having two or more polymerizable groups in one molecule are applied to the surface of the molded product, and then active energy rays are irradiated. There are known compounds that undergo radical polymerization.

[Problem that the invention seeks to solve]

However, among the conventional coating material compositions mentioned above, those using thermosetting resins have a slow curing speed, resulting in poor productivity of resin-coated molded products, and the water resistance of the cured film, especially in hot water, etc. There was a problem of insufficient durability against. On the other hand, in the case of products that undergo radical polymerization of polyfunctional monomers or oligomers, the hardness of the cured film is generally low (although it varies depending on the type of monomer used). It is difficult to obtain effective results, and those that have relatively good properties have disadvantages such as poor adhesion to the coated material and poor water resistance, which has the problem of not being able to fully achieve the intended purpose of coating. .

Therefore, in order to overcome the above problem, the inventors first developed a) a specific polyfunctional monomer having a molecular weight of 900 or less and having three or more (meth)acryloyl groups in one molecule. , b) a specific bifunctional monomer having a tricyclo ring structure in the molecule in a specific ratio, and a coating composition containing a polymerization initiator was proposed.

According to the composition according to the above proposal, it can be cured very quickly by applying it to the surface of a material to be coated such as a synthetic resin molded article and then heating it or irradiating it with ultraviolet rays or electron beams. It has been found that it has high hardness and excellent adhesion to the coated material, and also has excellent water resistance and abrasion resistance, and can solve all of the problems of the conventional coating materials.

This invention is based on the above-mentioned prior invention and further improves this prior invention, that is, it can solve the problems of the conventionally known coating materials as well as the prior invention, and has further improved wear resistance than the prior invention. The object of the present invention is to provide an industrially extremely useful coating material composition that can form a crosslinked cured film with excellent properties and is even more satisfactory in terms of various performances such as surface hardness.

[Means for solving problems]

As a result of intensive studies to achieve the above object, the inventors have discovered that a specific amount of a specific fluorine-based (meth)acrylate compound is combined with a specific monomer mixture consisting of components a and b according to the proposal. When used, it is possible to form a cured film with good curability that has excellent adhesion to the material to be coated and water resistance, similar to the case of the coating material composition of the proposal, and the above-mentioned film is the composition of the proposal. The present invention was completed based on the knowledge that it exhibits much improved abrasion resistance compared to the above, and is also excellent in terms of surface hardness, and exhibits extremely suitable performance as a coating material composition. It's arrived.

That is, this invention comprises a) 10 to 70% by weight of a polyfunctional monomer having a molecular weight of 900 or less and having three or more (meth)acryloyl groups in one molecule, and b) the following formula; Y + , Yz is a (meth)acryloyl group] 10 to 70% by weight of a bifunctional monomer represented by C) the following formula; is a fluorine-substituted alkyl group having 1 to 20 carbon atoms] Fluorine-based (meth)acrylate compounds 10 to
60% by weight, and the above a and b.

A monomer mixture in which the total amount of component C is 100% by weight,
d) A coating composition characterized in that it contains a polymerization initiator.

In this specification, (meth)acryloyl group refers to acryloyl group and/or methacryloyl group represented by the following formula; (R is hydrogen or methyl group), and (meth)acrylate refers to acrylate and/or methacryloyl group. or methacrylate, and (meth)acrylic acid means acrylic acid and/or methacrylic acid, respectively.

[Structure and operation of the invention]

The polyfunctional monomer as component a used in this invention is a monomer having a molecular weight of 900 or less and having 3 to 6 (meth)acryloyl groups in one molecule; The body mainly contributes to improving the curability of the coating material composition, and also serves as an effective component in forming a cured film with high crosslinking density and increasing the hardness and abrasion resistance of the film. .

As mentioned above, the molecular weight of this polyfunctional monomer is 900
It is preferably below 810, and the lower limit is usually up to 350.

In terms of molecular weight per (meth)acryloyl group, it is 3
00 or less, preferably 270 or less, and the lower limit is usually 1
up to 00. It should be noted that if the molecular weight of the polyfunctional monomer exceeds 900, the hardness and abrasion resistance of the cured film will be impaired, so it is not suitable.

Specific examples of such polyfunctional monomers include trimethylolpropane tri(meth)acrylate, pentaglycerol tri(meth)acrylate, pentaerythritol tri or tetra(meth)acrylate, dipentaerythritol tri.

Examples include tetra, penta or hexa(meth)acrylate, and hexa(meth)acrylate of an ε-caprolactone adduct of dipentaerythritol.

These monomers may be used alone or in combination of two or more.

The bifunctional monomer as component b used in this invention has a tricyclo ring structure represented by the above formula,
It is a monomer having two (meth)acryloyl groups at both ends of the molecule. This monomer itself has the characteristics of low viscosity, good dilutability, and good curability. It acts as a very effective component in forming a film.

Among such bifunctional monomers, tricyclo[
5.2.1! -6) Decane-3,8 (or 3.9 or 4.8)-diyl dimethylene diacrylate is preferably used.

The fluorine-based (meth)acrylate compound as component C used in this invention is a compound having one (meth)acryloyl group and one fluorine-substituted alkyl group in the molecule represented by the above formula. Mainly has the function of further improving the abrasion resistance of the cured film based on component a, and also has the function of further increasing the surface hardness, and further improves water resistance, acid discoloration resistance, alkali discoloration resistance, and resistance to alkali discoloration. It functions as a component that gives good results in terms of various performances such as chemical resistance such as volatile oil resistance and stain resistance.

In addition, in the fluorine-substituted alkyl group (Rf) in the above formula, the number of carbon atoms is limited to 1 to 20 because if the number of carbon atoms is larger than 20, the above function will deteriorate, and the above a
This is because problems arise in terms of compatibility with component b. Such a fluorine-substituted alkyl group may be a perfluoroalkyl group in which all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms, or a partially fluorinated alkyl group in which some of the hydrogen atoms are substituted with fluorine atoms. It may also be an alkyl group.

Specific examples of such fluorine-based (meth)acrylate compounds include 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (
Meta) acrylate, 2, 2, 3, 3, 4, 4, 5, 5
-Octafluoropentyl (meth)acrylate, 2.2
-3,4,4,4-hexafluorobutyl (meth)acrylate, IH-IH-2H-2H-hebutadecafluorodecyl acrylate, and the like. These fluorine-based (meth)acrylate compounds may be used alone or in combination of two or more.

In this invention, the polyfunctional monomer as the above-mentioned component a, the bifunctional monomer as the above-mentioned component, and the above-mentioned C
A monomer mixture consisting of a fluorine-based (meth)acrylate compound is used as an essential component, but the proportion of these monomers used is as follows: 10 to 70% by weight, preferably 20% by weight
~60% by weight, 10 to 70% by weight, preferably 20 to 60% by weight of bifunctional monomers as component B, and fluorine-based monomers as component C (
The proportion should be between 10 and 60% by weight of meth)acrylate compound, preferably between 15 and 40% by weight.

That is, by setting the a, b, and C components within the above range, and determining the usage amount according to the type of each component so that the total amount of these a, b, and C components is 100% by weight. , has excellent curing properties, excellent adhesion and water resistance of the cured film, and highly improved abrasion resistance.
Furthermore, it is possible to obtain a coating material composition that satisfies various properties such as surface hardness, chemical resistance, and stain resistance; outside the above range, the coating material composition will be inferior in any of the above-mentioned properties.
A high-performance coating composition as the object of this invention cannot be obtained.

In addition, if necessary, other monomers may be added to the monomer mixture consisting of the above components a, b, and c, for example, for the purpose of imparting various functions such as antistatic properties, slip properties, and antifogging properties to the cured film. Various vinyl monomers that can be polymerized by ultraviolet rays can be added, and silicone and (meth) monomers can be added to provide various functions such as surface smoothness, blocking resistance, and antifoaming properties.
Additives such as acrylic copolymers can also be added. These optional monomers and additives are usually contained in an amount of 5% by weight or less based on the total amount of the a, b, and C components so as not to impair the characteristics of the monomer consisting of the a, b, and C components. It is desirable to suppress it.

The polymerization initiator used as component d in this invention is appropriately selected depending on the means for curing the coating material composition. That is, since the coating material composition of the present invention can generally be cured by thermal polymerization or irradiation with light (ultraviolet light), electron beams, active energy rays, etc., a polymerization initiator suitable for these curing means can be used. Among the above-mentioned curing means, ultraviolet irradiation is a particularly recommended method because it can cure the coating material composition most rapidly. Various photopolymerization initiators known as sensitizers are used.

For example, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-methylbenzoin, benzophenone, Michler's ketone, 1-hydroxycyclohexylphenyl ketone, benzyl, benzyl dimethyl ketal, benzyl ethyl ketal, anthraquinone, methylanthraquinone, 2・2-jethoxyacetophenone, 2-methylthioxanthone, 2-isopropylthioxanthone,
Examples include 2-chlorothioxanthone, anthracene, 1,1-dichloroacetophenone, methylorthobenzoylbenzoate, and those used in combination with small amounts of sensitizing aids such as amines.

As mentioned above, the coating material composition of the present invention can be cured by thermal polymerization. Examples of thermal polymerization initiators include tertiary butyl peroctoate and tertiary butyl pervivalate. peresters, percarbonate esters such as bis-(4-tert-butylcyclohexyl)-peroxydicarbonate, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as di-tert-butyl peroxide and dicumyl peroxide. peroxides, such as hydroperoxides such as cyclohexanone peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, and their combinations with metal promoters such as cobal)-II salts of 2-ethylhexanoic acid and naphthenic acid. Examples include system polymerization initiators, and other azo compounds can also be used.

The amount of the polymerization initiator used as component d is usually 0 parts by weight per 100 parts by weight of the monomer mixture (components a, b, c and other monomers other than the above used as necessary). .1 to 10 parts by weight, preferably 0.5 to 6 parts by weight. If the amount is too large, the cured film may be colored or the water resistance may be deteriorated, and if the amount is too small, the curability deteriorates, so neither is preferable.

The coating material composition of this invention contains 40 to 70 of each of the above components.
The composition is obtained by stirring and mixing for a predetermined period of time at a temperature of approximately 0.99°C, and if necessary, various additives such as antioxidants and storage stabilizers may be added to this composition so that the total amount of the composition is usually 0.5%.
It may be included in an amount of about 1 to 10% by weight.

In order to form a crosslinked cured film on the surface of a material to be coated, such as a synthetic resin molded article, using the coating material composition obtained in this way, first the above composition is applied to the surface of the material to be coated, so that the thickness after curing is Apply to a specified thickness.

Various materials such as metal articles and wood articles can be used as the covering material, but synthetic resin molded products, which are most susceptible to surface scratches, are mainly used.As synthetic resin molded products, thermoplastic resins, thermosetting resins, etc. Various synthetic resin molded products such as polymethyl methacrylate resin, polycarbonate resin, polyallyl diglycol carbonate resin, polystyrene resin, acrylonitrile-styrene copolymer resin (As resin), polyvinyl chloride resin, acetate resin, ABS resin Specific examples include sheet-like molded products, film-like molded products, rod-like molded products, and various injection molded products manufactured from polyamide resins, polyester resins, and the like.

Among these synthetic resin molded products, molded products made from polymethyl methacrylate resin, polycarbonate resin, etc. are known for their chemical properties and heat resistance.

It is often used to take advantage of its properties such as impact resistance.
In addition, since there is a strong demand for improved wear resistance, it is particularly preferred as a synthetic resin molded article to which the coating composition of the present invention is applied.

Various methods such as brush coating, flow coating, spray coating, spin coating, and dip coating can be employed to apply the coating composition of the present invention to the surface of such a material to be coated. Among these, coating workability.

From the point of view of the smoothness, uniformity, and adhesion of the coating to the material to be coated, the dip coating method is most preferable. It is desirable to dilute it with a suitable organic solvent.

The organic solvent used for dilution is one that can be mixed with the coating material composition of the present invention to form a uniform solution, has a boiling point of 50°C or more and 200°C or less at normal pressure, and has a viscosity of 10°C or less at normal temperature.
Organic solvents having a centipoise or less are preferred.

Types of organic solvents include alcohols such as ethanol, isopropanol, normal propazol, isobutyl alcohol, and normal butyl alcohol, aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene, and ketones such as acetone and methyl ethyl ketone. , ethers such as dioxane, and acid esters such as ethyl acetate, propyl acetate, n-butyl acetate, and ethyl propionate. These organic solvents may be used alone or in combination of two or more.

The amount of the organic solvent to be used is preferably about 30 to 70% by weight in the solution obtained by dissolving the above-mentioned coating composition in the organic solvent. If the amount used is too small, good results will not be obtained in the smoothness and uniformity of the cured film, and if it is too large, the film thickness will become too thin and the surface hardness and abrasion resistance of the coated material will not be sufficiently improved. It becomes difficult.

The coating amount of the coating material composition is such that the thickness of the cured film is 1 to 1.
It is desirable to set the coating amount to 20 μm, preferably in the range of 5 to 10 μm. If the coating amount is too thin, the abrasion resistance and surface hardness of the coated material cannot be sufficiently improved, as described above. Furthermore, if the coating is applied in an excessively thick amount, curing by ultraviolet irradiation or the like may be poor, adhesion to the material to be coated may be reduced, and cracks or haze may easily occur in the cured film.

After the coating material composition of the present invention is applied to the surface of the material to be coated in this manner, it is cured by an appropriate means, thereby imparting high hardness and wear resistance to the surface.

A crosslinked cured film with excellent water resistance and adhesion can be formed. The curing means is usually 20 to 2.
Electron beam taken out from a 000KV electron beam accelerator, α
It is also possible to irradiate active energy rays such as radiation, β rays, γ rays, etc., or apply heat.
As mentioned above, it is most desirable to employ the method of irradiating ultraviolet rays.

〔Effect of the invention〕

As described above, the coating material composition of the present invention contains a specific polyfunctional monomer as the C component, a specific bifunctional monomer as the b component, and a specific fluorine-based monomer (as the C component). The main component is a monomer mixture formed by combining a meth)acrylate compound in a specific ratio, so by applying this to the surface of the material to be coated and curing it, it improves the adhesion and water resistance of the material to the material to be coated. Furthermore, the wear resistance has been significantly improved, the surface hardness has been further increased, and the properties such as acid discoloration resistance, alkali discoloration resistance, chemical resistance such as volatile oil resistance, and stain resistance have been improved. It is possible to form a cured film with excellent curability.

Therefore, according to this invention, automobile-related.

It is possible to provide a coating material composition that is extremely useful as a coating material for preventing surface scratches on various articles, especially synthetic resin molded articles, in various fields such as electronic/electrical, architectural, and optical fields.

〔Example〕

EXAMPLES Below, examples of the present invention will be described in more detail. In addition, in the following, parts shall mean parts by weight.

Example 1 57 parts of dipentaerythritol hexaacrylate (molecular weight 578) as component C and Y in the above formula as component b
,,Y! are both acryloyl groups, bifunctional monomer 2
7 parts, 16 parts of 2,2,2-trifluoroethyl acrylate as component C, and 5 parts of a polymerization initiator consisting of benzyl dimethyl ketal as component d are stirred and mixed at a temperature of 40 to 70°C. The solution was diluted with 100 parts of a 1:1 mixed solvent of toluene and isopropyl alcohol to obtain a coating composition solution of the present invention.

In addition, the bifunctional monomer of the above-mentioned component is tricyclo[5.2.18°6]decane-3,
8 (or 3.9 or 4.8) - diyl dimethylene diacrylate mixture (molecular weight 304; mixture is 3
．． 8-13.9- or 4°8-).

Examples 2 to 5 The same procedure as in Example 1 was carried out except that the monomer mixture consisting of components a, b, and C, the polymerization initiator as component d, and the type 1 composition of the organic solvent were changed as shown in the table below. A coating material composition solution of this invention was obtained.

In addition, in the table, each symbol indicating a monomer, a polymerization initiator, and an organic solvent is as follows.

BDK, Benzyldimethyl Kecool IPA: Isobrobyl Alcohol Comparative Examples 1 to 4 Coating was carried out in the same manner as in Example 1, except that the monomer, polymerization initiator, and organic solvent (2) compositions were changed as shown in the table below. A material composition solution was obtained.

Cured films were formed using the coating material composition solutions of the above Examples and Comparative Examples in the following manner. That is, a polycarbonate resin plate (trade name: S-3000U manufactured by Mitsubishi Gas Chemical Co., Ltd., hereinafter referred to as PC board) with a thickness of 3 nm is immersed in each solution, pulled out, and each solution is applied to the surface of the resin plate after curing. The coating was applied to a thickness of 10 partsm, air-dried for about 5 minutes, and then cured by irradiation with ultraviolet rays using a mercury lamp (80 W/am) at an irradiation dose of 100 mJ/cd.

The hardened film thus formed was examined for pencil hardness, adhesion, abrasion resistance, and water resistance using the following methods. The results were as shown in the table below.

<Pencil hardness> According to JIS K-5400, the pencil hardness was measured using a load of 1-, and the hardness that did not cause scratches was defined as the pencil hardness.

Adhesion> A base grid test was conducted in accordance with JIS K-5400, and the operation of adhering cellophane tape (manufactured by Chiban) to the tape and peeling it off at once was repeated three times, and the number of remaining grids was shown.

Abrasion Resistance> Tests were conducted using a taper type abrasion tester in accordance with JIS K-7204. Appearance evaluation was performed by visual inspection after 500 rotations.

○... There is almost no scratch on the sample surface Δ... There is a little scratch on the sample surface ×... There is severe scratch on the sample surface Water resistance> Immerse the sample in pure water at 40℃ , after being left for 240 hours,
A test similar to the above adhesion test was conducted.

As is clear from the results in the above table, the coating material composition of the present invention has excellent adhesion to PC boards and water resistance, and has significantly improved abrasion resistance, as well as high surface hardness. It can be seen that a film can be formed with good curability.

In Examples 1 to 5 above, only monomers having an acryloyl group in the molecule are used as the monomers for components a, b, and c, but monomers having a methacryloyl group or an acryloyl group are used. It goes without saying that good results similar to those in Examples 1 to 5 can be obtained even when an appropriate combination of a compound having a methacryloyl group and a compound having a methacryloyl group is used.

Claims (1)

[Claims] (1) a) Polyfunctional monomer 10 to 10 with a molecular weight of 900 or less and having three or more (meth)acryloyl groups in one molecule
70% by weight, and b) 10 to 70% by weight of a bifunctional monomer represented by the following formula; ▲Mathematical formulas, chemical formulas, tables, etc.▼ and c) a fluorine-based (meth)acrylate represented by the following formula; Compound 10~
d) A polymerization initiator is contained in a monomer mixture consisting of 60% by weight and in which the total amount of components a, b, and c is 100% by weight.