JPS6397636A - Coating composition and resin molding prepared therefrom excellent in scratch resistance and flexibility - Google Patents

Abstract

PURPOSE:To obtain the title composition which can be easily cured by irradiation with an actinic radiation into a coating excellent in scratch resistance and flexibility, by mixing a specified polyfunctional monomer component with an organic solvent and a photopolymerization initiator. CONSTITUTION:A polyfunctional monomer component (A) is obtained by mixing 10-90wt% reaction product (a) of pentaerythritol tri(meth)acrylate (i) with a diisocyanate compound (ii) in an amount to provide an equivalent ratio to the residual OH groups of component (i) (NCO/OH) of 0.1-1.0 with 10-90wt% bifunctional monomer (b) of the formula (wherein R1-2 are each H or CH3, k, l, m and n are each 0-5, k+l=0-5 and m+n=0-5), e.g., 2,2-bis(4- acryloxyphenyl)propane and 0-30wt% polyfunctional monomer (c) other than components (a) and (b) (e.g., tetraethylene glycol diacrylate). 100pts.wt. component A is mixed with 10-900pts.wt. organic solvent (B) (e.g., ethyl Cellosolve) in which component A is soluble and 0-10pts.wt. photopolymerization initiator (C).

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a material that can be easily cured by irradiation with active energy rays and has scratch resistance, flexibility, heat resistance, boiling water resistance, solvent resistance, The present invention relates to a coating composition that can form a crosslinked film with excellent weather resistance and adhesion to various substrates, and to a resin molded article using the same that has excellent scratch resistance and flexibility.

(Conventional technology) Generally, resin molded products are lightweight and have excellent impact resistance.

It also has various advantages such as being inexpensive and easy to mold, and is used in a wide range of fields, but its surface hardness is lower than that of metals and glass, so it is difficult to mix with other items during storage and transportation. The disadvantage is that the surface is easily scratched by contact. Particularly in products that require transparency and beauty, scratches on the surface of resin molded products can significantly reduce their value.
As a result, it becomes unusable, so there is a strong demand to improve the scratch resistance of the surface. Various studies have been made in the past to improve these drawbacks.

For example, there are methods of applying organic coating materials such as melamine resin or inorganic coating materials such as organopolysiloxane resin and curing them with heat, but both methods have problems with workability, and organic coating materials Inorganic coating materials had drawbacks such as insufficient abrasion resistance and poor adhesion requiring primer treatment. On the other hand, a method in which a polyfunctional (meth)acrylate monomer is applied to the surface of a resin molded product and irradiated with active energy rays to form a cured film is superior in productivity and has excellent performance and durability. Due to its excellent scratch resistance and adhesion, much research has been conducted on it, and some of it has even been put into practical use.

However, as the applications of resin molded products have become more diverse in recent years,
There are an increasing number of applications where flexibility as well as abrasion resistance is important to the coating. Especially for thin plate molded products.

Processability such as punching and heat bending is required, but the conventional method of forming a cured film by irradiating a polyfunctional (meth)acrylate monomer with active energy rays does not have sufficient scratch resistance and flexibility. It is extremely difficult to obtain a coating of excellence,
At present, a coating material that is satisfactory for this purpose has not yet been obtained.

(Problems to be Solved by the Invention) As a result of extensive research, the present inventors have found that a coating composition containing specific components in specific proportions is easily cured and resistant to active energy rays. Excellent abrasion resistance and flexibility,
In addition, it forms a coating with excellent heat resistance, boiling water resistance, solvent resistance, and adhesion to various substrates, and by using the coating composition in resin moldings, it has excellent scratch resistance and flexibility. The inventors discovered that a resin molded product with excellent properties could be obtained and completed the present invention.

(Means and effects for solving the problems) That is, the present invention provides a reaction product (a) of pentaerythritol tri(meth)acrylate and a diisocyanate compound.
~90% by weight, the following general formula (D is 110 CJ = 0 110? (wherein, R1 and R2 each represent a hydrogen or methyl group which may be the same or different, k, t , m, fi must be integers of θ~5, and +tFio~5, m +
n is an integer from 0 to 5. ) A bifunctional monomer (b) 1O to 900 to 90 parts by weight of a reaction product 0),
Other polyfunctional monomers (e) excluding difunctional monomers (b)
0 to 30% by weight (however, (a) + (b) 10% by weight)
0 weight person. ) Polyfunctional monomer component 1 consisting of
00 parts by weight, 10 to 900 parts by weight of an M solvent (B) capable of dissolving the polyfunctional monomer component, and 0 to 10 parts by weight of a photopolymerization initiator (C). This invention relates to resin molded products with excellent scratch resistance and flexibility.

The reaction product (a) of pentaerythri(meth)acrylate and diisocyanate compound used in the present invention (hereinafter referred to as reaction product (a)) exhibits a very good reaction when irradiated with active energy rays. The cured film has excellent scratch resistance and relatively good flexibility. −
2/taerythritol tri(meth)acrylate is usually commercially available as a mixture with tet 2(meth)acrylate, but there is no need to separate it, and the mixture may be used as it is. Further, as the diisocyanate compound, for example, evahexamethylene diisocyanate, inphorone diisocyanate, xylylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, etc. can be used, but in the present invention, aliphatic Alternatively, alicyclic diisocyanate compounds are preferred. The amount of diisocyanate compound used is such that the -NCO10H equivalent ratio is 0.1 to i with respect to the remaining OH groups of pentaerythritol tri(meth)acrylate,
o, preferably in the range of 0.2 to 0.8. If it is less than 0.1, the flexibility will be insufficient, and if it is more than 1.0, the adhesion of the coating will decrease, which is not preferred. The diisocyanate compound reacts with the 0H group contained in pentaerythritol tri(meth)acrylate to form a urethane bond, but by creating a specific proportion of the reaction product (0), the cured film has flexibility and is bondable to the base material. This brings about favorable effects such as adhesion and surface smoothness. The reaction product (a) has multiple uses. If the amount used is less than 10% by weight, sufficient scratch resistance will not be obtained, and if it exceeds 90% by weight, flexibility will be insufficient.

cormorant. ) improves the flexibility of the cured film without reducing its scratch resistance, and also does not impair its curability when irradiated with active energy rays. In general formula (1), k+
When the number of 1 and m + n exceeds 5, the scratch resistance, adhesion, and weather resistance of the cured film are low, such as 2,2-bis(4-acryloxyphenyl) 7'
o t4no, 2.2-bis(4methacryloxyphenyl)solonone, 2.2-bis(4methacryloxyethoxyphenyl)pronokune, 2.2-bis(4methacryloxyethoxyphenyl)propane, 2- (4acryloxydiethoxyphenyl), 2'-(4acryloxydiethoxyphenyl)zolon/4', 2,2-bis(4acryloxydiethoxyphenyl)propane, 2,2-bis(4
methacryloxycyedokylephenyl) pronoyan, 2,
2-bis(4-acryloxyglopoxyphenyl)propane, 2,2-bis(4-methacryloxyglopoxyphenyl)sol/4-one, 2,2-bis(4-acryloxyethoxyglopoxyphenyl)pro/ parable, 2.2-bis(4
Examples include methacryloxyethoxyglopoxyphenyl) pronoben, among which 10 to 900 to
It is 90 parts by weight or 30-650-65 parts by weight. If the amount used is less than 10 parts by weight, sufficient flexibility will not be obtained, and if it exceeds 90 parts by weight, the scratch resistance will be insufficient.

In the present invention, the polyfunctional monomer component) may be composed of the above-mentioned reaction product (a) and the bifunctional monomer (b), but if necessary, the object of the present invention may be Other polyfunctional monomers may be used in combination without departing from the range. Other polyfunctional monomers (c) that can be used include 1, such as N-vinylpyrrolidone, vinylpyridine,
Vinyl compounds such as divinylbenzene, allyl compounds such as realyl phthalate, triallyl isocyanurate, trimethylolglopan diallyl ether, maleimide compounds such as n-butylmaleimide and cyclohexylmaleimide, methoxyethyl (meth)acrylate, ethoxydiethylene glycol ( meth)acrylate, phenoxyethyl(meth)acrylate, hydroxyethyl(
meth)acrylate, 1.4butanediol di(meth)
Examples include (meth)acrylates such as acrylate, diethylene glycol di(meth)acrylate, triglopyre/glycol di(meth)acrylate, trimethylolglono and tri(meth)acrylate, and one or more of these Mixtures can be used. The amount of other polyfunctional monomers (c) to be used is 0 to 30% by weight, preferably O
It is in the range of ~20% by weight. If the amount used exceeds 30% by weight, a coating composition with excellent scratch resistance and flexibility cannot be obtained.

Organic solvent (B) capable of dissolving the polyfunctional monomer component used in the present invention (hereinafter referred to as organic solvent (B)).

) Examples include alcohols such as ethanol, ingropanol, n-butanol, and isobutanol; aromatic hydrocarbons such as benzene, toluene, and xylene; and esters such as ethyl acetate, butyl acetate, amyl acetate, and ethyl lactate. Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and diacetone alcohol; Ethers such as methyl cellosolve, methyl cellosolve, and butyl cellosolve;
One or a mixture of two or more of these can be used. In addition, polymerizable monomers such as methyl acrylate, butyl acrylate, methyl methacrylenide, styrene, and vinyl acetate can also be used as part of the organic solvent (B), as long as they have the same effects as these organic solvents (@). May be used as seeds. The organic solvent (B) is used to further improve the coating workability of the coating composition and the adhesion of the cured film to the substrate, and contains 100 parts by weight of the above-mentioned polyfunctional monomer component (A). 10 to 900 parts by weight, preferably 40 to 300 parts by weight
Use within parts by weight. The amount of organic solvent (B) used is 1
If the amount is less than 0 parts by weight, it will be difficult to adjust the viscosity of the coating composition to the optimum level in terms of coating workability.

This is not preferable because it also reduces smoothness. In addition, organic solvents (
When using B), the type and amount can be selected appropriately depending on the application method, etc. However, depending on the type of resin used as the base material, devitrification and cracks may occur, so Caution is required.

In the present invention, in order to apply the coating composition to the surface of a resin molded article and form a cured film, it is necessary to irradiate the surface with active energy rays such as ultraviolet rays, electron beams, and radiation. Among these, the method of irradiating with ultraviolet rays is the most practical method because the equipment is simple and other reasons.

In order to cure by irradiating ultraviolet rays, it is necessary to add a photopolymerization initiator (C) that can initiate a polymerization reaction by irradiating ultraviolet rays. Examples of the photopolymerization initiator C) used in the present invention include benzoin ethers such as benzoin ethyl ether and benzoin isobutyl ether; benzyl ketals such as dimethoxyphenylacetophenone and hydroxycyclohexylphenyl ketone;
Examples include acetophenones such as jetoxyacetophenone; ketones such as benzophenone, benzyl, and 2-chlorothioxanthone; one type or a mixture of two or more of these can be used. The amount of these photopolymerization initiators C) used is 10% of the polyfunctional monomer component (A).
θ to 10 fi parts, preferably 0.1
~6 parts by weight. The amount of photopolymerization initiator (C) used is 10
If the amount exceeds 1 part by weight, it is not preferable because the abrasion resistance and weather resistance of the coating will decrease.

The coating composition of the present invention is formed by blending the polyfunctional monomer component (4), the organic solvent (B) and the photopolymerization initiator (C) in the above-mentioned amounts. Accordingly, known additives such as ultraviolet absorbers, antioxidants, plasticizers, leveling agents, antifoaming agents, and antistatic agents may be added.

The resin molded article of the present invention having excellent scratch resistance and flexibility is obtained by applying the coating composition described above to the surface of various resin moldings and curing it with active energy rays. Applicable resin molded products include molded products of various resins, regardless of whether they are thermoplastic resins or thermosetting resins, such as polymethyl methacrylate resin, polystyrene resin, acrylonitrile, -styrene resin, ABS resin, polycarbonate resin, and polyester resin. Examples include sheet-like molded products, film-like molded products, rod-like molded products manufactured from glycol cargenate resin, hard vinyl chloride resin, cellulose acetate resin, cellulose acetate butyrate resin, nylon resin, polyacetal resin, polyester resin, etc. I can do things. Among these molded products, resin molded products such as polymethyl methacrylate resin and polycarbonate resin take advantage of their properties such as optical properties, impact resistance, heat resistance, and weather resistance, and can be used in applications where glass has traditionally been used. This is particularly preferable because there is a strong demand for alternatives to , and there is also a strong demand for improved scratch resistance. These various resin moldings may be coated with the coating composition as they are, but if necessary, corona discharge or
Resin molded products that have undergone pretreatment such as glow discharge, ozone oxidation, and hydrolysis, coating with an adhesive layer, and printing can also be used.

Further, as a method for applying the coating composition to the resin molded article, commonly used methods such as brush coating, dip coating, roll coating, spray coating, flow coating, etc. can be suitably employed.

As for the coating amount, the thickness of the cured coating film is 1 to 20 μm.

Preferably, it is necessary to adjust the thickness to a range of 2 to 10μ. 1
If it is thinner than μ, the scratch resistance will be poor, and if it exceeds 20μ, the internal strain will increase, resulting in a hardened film with poor flexibility, resulting in a decrease in the durability of the resin molded product. Undesirable.

(Effects of the Invention) The coating composition of the present invention can be easily cured by irradiation with active energy rays, and has excellent scratch resistance, flexibility, heat resistance, boiling water resistance, solvent resistance, weather resistance, and various basic properties. Forms a crosslinked film with excellent adhesion to materials.

Therefore, the resin molded products of the present invention obtained by using the coating composition in various resin molded products have excellent scratch resistance, flexibility, etc.
Covers for windows, lenses, clocks and instruments, covers for lighting equipment,
It can be suitably used for applications such as windshields.

(Examples) Hereinafter, embodiments of the present invention will be described in detail using Examples, but the present invention is not limited to the following Examples. In addition, evaluation in Examples was performed by the following method.

(1) Scratch resistance: Abrasion resistance tester (Yasuda Seiki Seisakusho Model ■)
#000 steel wool under 500g load using
Damage to the surface of the test piece after 0 reciprocation was observed.

○ Almost no change Δ Slight scratches × Significant scratches (2) Flexibility: After forming a cured film on a polycarbonate resin sheet molded product with a thickness of 1 cm, the length is 15 cm.
A test piece cut out into a rectangular shape with a width of 5 mm was wound around the outer circumference of a circle with a diameter of 3 m to observe the state of the coating.

○ No abnormality Δ A slight crack occurred The residual rate of the cured film was examined.

Δ 51/100 to 99/100
Comprehensive evaluation was made in terms of flexibility and adhesion.

○ Almost no change from the film before heat treatment × Significant change compared to the film before heat treatment (5) Boiling water resistance: Appearance and scratch resistance of the film after 20 hours of immersion in boiling water , flexibility, and adhesion were comprehensively evaluated.

There was almost no change from the coating before immersion in boiling water × There was a significant change compared to the coating before immersion in boiling water Reference Example 1 Equipped with a stirrer, thermometer, water separator with cooler, and gas blowing pipe Intererythritol 500 in a four-loaf flask
1. Acrylic acid 87511. p-) Luenesulfonic acid 7
0g, noihydroquinone 0.175I and n-hexane 530. ! IF was added, and the reaction mixture was heated and stirred while blowing 1.51/hr of air into the reaction mixture, and the water produced by the reaction was taken out of the reaction system.

After 6 hours of reaction, the reaction mixture was cooled to room temperature, separated into two layers, the n-hexane layer was removed, and the ester layer was diluted with trichlorethylene to a concentration of about 5 Oqb. Then, neutralize with 50% sodium hydroxide aqueous solution containing 10% sodium chloride, and further 0.5% sodium hydroxide solution containing 10% sodium chloride.
d and 600 ml of an aqueous sodium chloride solution. The solvent was distilled off from the ester solution containing the solvent at 50° C. under reduced pressure (achieved vacuum 5 mHg). The ester yield was 900I, and its composition (according to gas chromatography) was 54 pentaerythritol triacrylate, and the viscosity (B-type viscometer) was 700 cps/25°C.Reference Example 2 Stirrer, thermometer, dropping funnel, Pentaerythritol triacrylate) 314!1 (OH group amount 1.0 mole) obtained in Reference Example 1 was placed in a four-loaf flask equipped with a gas blowing tube.
, 0.42 g of diptyltin dilaurate were added and stirred while blowing in a small amount of dry air.

Then 42 g of hexamethylene diisocyanate (NCO
The group JtO15Qmole) was added from the addition funnel over a period of 1 hour. After the addition, the temperature was raised to 80°C for 2 hours at 40-50°C, and the reaction was continued for 7 hours, and the reaction product was collected as a transparent liquid with a viscosity of 4850 cps/25°C (1
) was obtained.

Comparative Reference Example 1 The same operation as in Reference Example 2 was carried out except that the amount of hexamethylene diisocyanate used in Reference Example 2 was changed to 959 (NCO group amount 1.13 mole), and the viscosity was 87,000.
cps/25°C viscous liquid comparative reaction product (obtained @Reference Example 3 Hexamethylene diisocyanate used in Reference Example 2) 42
The procedure was carried out in the same manner as in Reference Example 2, except that 55.6p (NGO group amount: 0.50 mole) of inphorone diisocyanate was used instead of g, and the viscosity was 13,300 cps/2.
A viscous liquid reaction product (2) of S° C. was obtained.

Example 1-#Toxin 2, Comparative Examples 1 to 6 Using the reaction product (1) obtained in Reference Example 2, a coating composition was prepared according to the formulation shown in Table 1, and a 1-inch thick methacrylic It was applied uniformly to a resin plate (Mitsubishi Rayon ■ back, Acrylite) using a percoater.

After leaving it in a hot air dryer at 60°C for 3 minutes to volatilize the solvent, it was irradiated with ultraviolet rays from a high-pressure mercury lamp (manufactured by Iwasaki Electric, HO3-L31) for 12 seconds from a distance of 10cWI to obtain a thickness of 3.
A resin molded article with a cured film of ~4 μm formed on the surface was obtained. The performance of these resin molded products was as shown in Table 1.

As is clear from Table 1, only when the composition satisfies the conditions for the coating composition of the present invention, the coating composition has excellent curability, and the resin has both good scratch resistance and flexibility. A molded article was obtained.

Examples 3 to 7, Comparative Examples 7 to 9 Using the reaction products (1) to (2) obtained in Reference Examples 2 to 3 and the comparative reaction product (1) obtained in Comparative Reference Example 1 A coating composition was prepared according to the formulation shown in Table H, and a thickness of 1 cm was prepared.
The cured film was coated on a polycarnate molded plate (manufactured by Nippon Shokubai Chemical Co., Ltd., Epocard) using a percoater so that the thickness of the cured film was 3 to 5 μm. After drying at 60° C. for 3 minutes, ultraviolet rays were irradiated for 6 seconds from a distance of 10 α to obtain a resin molded product with a cured film formed on the surface. The performance of these resin molded products was as shown in Table H.

As is clear from these results, a specific composition that satisfies the drafting of the coating composition of the present invention has both good scratch resistance and flexibility, and the coating used in Example 4 has even better properties. The composition was uniformly applied to a 1 m thick polycarbonate molded plate (Nippon Shokubai Chemical Co., Ltd., Epocarpo) using a percoater.

After drying at 60℃ for 3 minutes, from a distance of 15z to 3k
Ultraviolet rays from a W high-pressure water chain lamp were irradiated for 10 seconds.

The performance of the thus obtained molded products having coatings with different thicknesses formed on their surfaces was as shown in Table 3).

As is clear from Table M and Table ■, it can be seen that when the film thickness is greater than 20μ, the adhesion, flexibility, and durability are poor.

Medium I DPHA Diintererythritol hexaacrylate *4 TEGDA Tetraethylene glycol diacrylate 5 NPGDA *Opentyl glycol diacrylate $6 DEA Ethoxydiethylene glycol acrylate *7 18A
Inbonyl acrylate umbrella 8Tel) Luene

Claims (1)

[Claims] 1. Reaction product of pentaerythritol tri(meth)acrylate and diisocyanate compound (a) 10-9
0% by weight, the following general formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1 and R_2 each represent hydrogen or methyl group, which may be the same or different, and k, l, m, n
is an integer from 0 to 5, k+l is an integer from 0 to 5, and m+n is an integer from 0 to 5. 10 to 90% by weight of the difunctional monomer (b) shown in ) and the reaction product (a), and other polyfunctional monomers (c) other than the bifunctional monomer (b) 100 parts by weight of a polyfunctional monomer component (A) consisting of 0 to 30% by weight (however, (a) + (b) + (c) is 100% by weight), the polyfunctional monomer Organic solvent (B) capable of dissolving body component (A) 1
0 to 900 parts by weight, and 0 to 10 parts by weight of a photopolymerization initiator (C), which is cured by active energy rays and has scratch resistance.
A coating composition capable of forming a film with excellent flexibility. 2. The amount of the photopolymerization initiator (C) used is 0.01 to 10 parts by weight per 100 parts by weight of the polyfunctional monomer component (A), and the active energy ray is ultraviolet rays. 1
The coating composition described in Section 1. 3. Reaction product of pentaerythritol tri(meth)acrylate and diisocyanate compound (a) 10-9
0% by weight, the following general formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1 and R_2 each represent hydrogen or methyl group, which may be the same or different, and k, l, m, n
is an integer from 0 to 5, k+l is an integer from 0 to 5, and m+n is an integer from 0 to 5. 10 to 90% by weight of the difunctional monomer (b) shown in ) and the reaction product (a), and other polyfunctional monomers (c) other than the bifunctional monomer (b) 100 parts by weight of a polyfunctional monomer component (A) consisting of 0 to 30% by weight (however, (a) + (b) + (c) is 100% by weight), the polyfunctional monomer Organic solvent (B) capable of dissolving body component (A) 1
A coating composition consisting of 0 to 900 parts by weight and 0 to 10 parts by weight of a photopolymerization initiator (C) is applied to a resin molded article and cured with active energy rays to provide scratch resistance and flexibility. Excellent resin molded product. 4. The amount of the photopolymerization initiator (C) used is 0.01 to 10 parts by weight per 100 parts by weight of the polyfunctional monomer component (A), and the active energy ray is ultraviolet rays. 3
A resin molded product with excellent scratch resistance and flexibility as described in Section 1. 5. A resin molded article with excellent scratch resistance and flexibility according to claim 3 or 4, wherein the resin molded article is a molded article of polymethyl methacrylate resin or polycarbonate resin.