JPS62286738A - Manufacture of decorative board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for obtaining a decorative board by impregnating wood with a specific photocurable resin and photocuring it. be.

[Conventional technology]

Previously, there have been attempts to impregnate wood with a photocurable resin and cure it only by light irradiation, but since the resin impregnated inside the wood has poor photocurability, organic peroxides were used in combination. In all cases, the surface was photocured and then heated to harden the interior.

However, such a method has the drawback that it lacks the advantage of using a photocuring system, which cures quickly and has the potential to significantly reduce the number of man-hours for manufacturing decorative laminates.

[Problem that the invention seeks to solve]

The present inventors impregnated the wood with a photocurable resin and irradiated it with light without using any other procedures, thereby improving not only the surface layer but also the resin impregnated inside the wood, which had been considered difficult until now. We have been conducting research on decorative laminates that have excellent physical properties by curing the resin, but surprisingly, we discovered that we could achieve our goals by specifying the structure and composition of the photocurable resin, and completed the present invention. I was able to do it.

[Means for Solving the Problems] That is, the present invention provides: (1) an epoxy resin having two or more epoxy groups in one molecule, and acrylic acid and/or methacrylic acid (hereinafter referred to as
Epoxyl acrylate resin (hereinafter referred to as epoxyl acrylate resin) which is obtained by reacting the epoxyl acrylate resin with substantially no epoxy groups (hereinafter referred to as epoxyl acrylate resin)20~
90% by weight, (2) General formula % Formula % (However, R1 is hydrogen or an alkyl group, aralkyl group, oryl group, R2, R, is hydrogen or a methyl group, m is 1 or 2 monoacrylate or monomethacrylate having an aromatic structure (hereinafter referred to as aromatic mono(meth)acrylate) 8
Using a photocurable resin obtained by using a photoreaction initiator of 0 to l OM 51% and (3+0.1% or more), wood'iR is completely impregnated with internal salt and then irradiated with light. By this, the inside is evenly hardened.

[For production]

The reason for specifying the composition in the present invention is as follows.

Epoxy acrylate resin has excellent photocurability and can be cured even when the resin is impregnated inside wood, but it has a high viscosity and requires the use of a diluent for practical purposes.

Conventionally, acrylic esters of polyhydric alcohols, such as trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and triethylene glycol diacrylate, have been used in conjunction with this diluent. .

However, it has been found that when these photocurable resins containing polyhydric alcohol acrylates are impregnated into wood and cured, cracks occur along the wood grain due to repeated cold and warm temperatures.

On the other hand, existing monofunctional monomers as described in the literature have some drawbacks and have problems in practicality.

To give an example of those mentioned in 2.3, when styrene and methacrylic acid esters including methyl methacrylate are used in combination with epoxy acrylate resin, the photocurability is significantly slowed down, and the parts impregnated inside the wood are does not cure and yield virtually no useful veneer.

Acrylonitrile and the like are problematic in terms of volatility and toxicity, and vinylpyrrolidone is water-soluble, so not all of it can be used in terms of curability.

Furthermore, acrylic esters have few practical uses due to various drawbacks such as odor, branch irritation, and softness.

The present inventors investigated Motsumar for use in conjunction with it because it has a low viscosity and can be easily impregnated into the inside of the wood, and the resin that has been impregnated into the inside hardens, and also has a low odor and is easy to handle.
Recognizing that the aromatic mono(meth)acrylate represented by the aforementioned general formula or OH01h (where R, R2, R, and m are as described above) meets the purpose, we were able to complete the present invention. Ta.

The epoxy acrylate resin used in the present invention is synthesized from an epoxy resin and (meth)acrylic acid.

Epoxy resins include various commercially available epoxy resins, such as bisphenol A diglycidyl ether type, bisphenol F diglycidyl ether type, and novolac polyglycidyl ether type.

Examples include a cycloaliphatic type obtained by oxidizing a double bond with peracetic acid, a glycidyl ester type, and the like, and any of them can be used as a raw material for the epoxy acrylate resin of the present invention.

Aromatic mono(meth)acrylates represented by the above general formula of the present invention can be obtained by reacting phenols with epihalohydrin, especially shrimp chlorohydrin, and further converting the reaction product into (
Synthesized by esterification with meth)acrylic acid.

As the phenol, phenol and substituted phenol are used. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an aralkyl group, and an aralkyl group, and an example of the phenol is phenol.

0-cresol, m-cresol, p-cresol, and mixtures thereof, 2,3-xylenol.

2.4-xylenol, 3,5-xylenol, 2.
Examples include 6-xylenol, ba, tertiary butylphenol, paraphenylphenol, and paracumylphenol.

It can also be synthesized by esterifying commercially available phenylglycidyl ether, talesylglycidyl ether, paratertiary-butylphenylglycidyl ether, or styrene oxide with acrylic acid or methacrylic acid.

The composition ratio of the mixture of epoxy acrylate resin and aromatic mono (meth)acrylate (hereinafter sometimes referred to as vinyl ester resin) is 20 to 90% by weight of epoxy acrylate resin and 10 to 80% by weight of aromatic mono (meth)acrylate. % by weight, preferably 40-70% by weight of epoxy acrylate resin and 30-60% by weight of aromatic mono(meth)acrylate. Optimal viscosity is 1-15
It's Boyz.

It is necessary to further add 0.1 (%) or more of a photoreaction initiator to this mixture to form a photocurable resin.

Initiators generally include a variety of commercially available products for this purpose, such as Merck's Darocure! +1173° Ciba Irgacure 11651. Benzophenone, etc. can be used in combination with accelerators such as Michler's ketone, dimethylaminoethanol, etc., if necessary.

The wood impregnated with the photocurable resin according to the present invention is not particularly limited. For example, the types include cedar, cypress, pine, Douglas fir, and Beihi.

Coniferous trees such as taihi, sen, spider, oak, and elm.

Any hardwood such as zelkova, birch, beech, etc. can be used.

The thickness of the thin plate is not particularly limited, but due to the relationship between UV transmittance and curing speed, it is 0.2 to 11 cm when industrially produced.
A suitable thickness is . Further, the moisture content of the thin plate is preferably 20% or less.

One of the features of using photocurable resin according to the present invention is impregnation,
After curing, it is difficult to produce cranks that follow the wood grain, which is common with this type of decorative board. Hardness is sufficient for practical use.

The photocurable resin according to the present invention can be colored as necessary. Also, when impregnating wood with resin, reduced pressure,
Measures such as pressurization can also be taken freely.

〔Example〕

Next, examples will be shown below to help understand the present invention.

Reference Example 1 Into a separable flask equipped with a stirrer, a reflux condenser, and a thermometer, 370 g of Epicoat 827 from Yuka Shell Epoxy Co., Ltd. as an epoxy resin and 14 g of acrylic acid were added.
4g, trimethylbenzylammonium chloride 1.
5g, 0.25g of hydroquinone, 120g
After reacting at ~130°C for 3 hours, an epoxy acrylate resin with an acid value of 6.1 was obtained.

Example 1 Epoxy acrylate resin 410 obtained in Reference Example 1
465 g of an acrylic acid ester having the structure shown below, which was obtained by esterifying phenyl glycidyl ether with acrylic acid in a conventional manner, was added to synthesize vinyl ester resin (A).

It was a yellowish brown liquid with a viscosity of 4.7 poise.

To 100 parts by weight of the vinyl ester resin (A), 2 parts of Darocure #1173 manufactured by Merck & Co., Ltd. was added as a photoinitiator to obtain a photocurable resin (B).

After impregnating a photocurable resin (B) under a reduced pressure of 3 to 511 mHg into a 75+n x 15 Q mm rice tsutsugi wood cut to a thickness of 0.8 mm, the excess resin was removed and a 25 μm thick piece was cut.
Covering both sides with a polyester film of
was passed through the tube at a speed of 2 m/min, and the tube was further turned over and subjected to the same treatment.

The treated wood from which the film was removed was completely cured to the inside, and the surface hardness was 2H.

Comparative Example 1 To 60 parts by weight of the epoxy acrylate resin produced in Reference Example 1, 30 parts of methyl methacrylate, 10 parts of styrene,
Add 2 parts of Darocure #1173 to photocurable resin (
C).

Photocuring was carried out under the same conditions as in Example 1, but only the surface was gelatinized and the inside was not cured at all.

Comparative Example 2 One epoxy acrylate resin produced in Example 1 50
Trimethylolpropane triacrylate 5 parts by weight
0 parts, 2 parts of Darocure #1173 plus photocurable resin (
D) was produced.

The hardened wood treated in the same manner as in Example 1 was hardened to the inside and had a hardness of 2 to 3H.

After leaving at -20℃ for 1 hour, at room temperature for 1 hour, then at 80℃
After being left for 1 hour, a cold/hot cycle test was conducted in which the decorative board manufactured in Comparative Example 2 was subjected to a cold/hot cycle test, and cracks occurred along the wood grain over the entire surface of the decorative board manufactured in Comparative Example 2 after one cycle.

However, the decorative board manufactured in Example 1 did not develop any cracks in tests up to 3 cycles.

Example 2' Epoxy acrylate resin 410 obtained in Reference Example 1
0-cresyl glycidyl ether was esterified with methacrylic acid in a conventional manner, and 510 g of a methacrylic ester having the following structure 011 0 C1l:1 l 1 was added to the resulting mixture, and the vinyl ester resin (B) was added to Synthesized.

It was a yellowish brown liquid with a viscosity of 3.9 poise.

To 100 parts of the vinyl ester resin (B), 3 parts of "Irgacure 11651" manufactured by Chiha Corporation was added as an initiator to prepare a photocurable resin.

Vinyl ester resin (B) was applied at 3 to 5 mHg to a 7.5 cm×l 5 cm hinoki A cut to 0.71 mm.
After impregnation under reduced pressure, photocuring was carried out in the same manner as in Example 1.

The hardness of the obtained decorative board was 3 in the 2H1 cold and heat repeated test.
The crank wouldn't turn on the cycle.

Reference Example 2 As a polyhydric carboxylic acid type epoxy resin, 350 g of “Epicron +1200” manufactured by Dainippon Ink Chemical Company G1,
Acrylic 1144g, ) Riphenylphosphine 1.5g
, 0.25 g of hydroquinone were reacted in the same apparatus as in Example 1 at 120 to 130° C. for 4 hours to obtain an epoxy acrylate resin with an acid value I of 1.4.

It was yellowish brown and sill-like.

Example 3 Epoxy acrylate resin 450 obtained in Reference Example 2
To the parts by weight, 360 g of acrylic ester having the following structure OH0 tic C1+2 0 CCU = Cl1z obtained by esterifying styrene oxide with acrylic acid by a conventional method was added, and vinyl ester resin (
C) was synthesized.

It was a yellowish brown liquid with a viscosity of 5.4 voids.

To 100 parts of vinyl ester resin (C), 3 parts of "Irgacure #651" manufactured by Ciba Corporation was added as an initiator to prepare a photocurable resin.

A scrap material of a 751@X150 dragon cut into 0.7 fins was impregnated with vinyl ester resin (C) in an amount of 3 to 5 mm and 1 g under reduced pressure, and then photocured in the same manner as in Example 1.

The hardness of the obtained decorative board was 3 in the 2H1 cold and heat repeated test.
The crank wouldn't turn on the cycle.

[Effects of the Invention] The decorative board obtained by the method of the present invention is produced only by light curing, so the curing cycle is short and economical, and cracks along the wood grain pattern do not occur due to repeated cold and heat tests, and it is highly durable. It is of hardness.

Patent applicant: Showa Kobunshi Co., Ltd. Daiken Kogyo Co., Ltd.

Claims (3)

[Claims] (1) 20 to 90% by weight of an epoxy to acrylate resin substantially free of epoxy groups, obtained by reacting an epoxy resin having two or more epoxy groups in one molecule with acrylic acid and/or methacrylic acid. , (2) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, R_1 is hydrogen, an alkyl group, an aralkyl group, an aryl group, and R_2 and R_3 are hydrogen or 80 to 10% by weight of monoacrylate or monomethacrylate having an aromatic structure represented by (a methyl group, m is an integer of 1 or 2), and (3) A method for producing a decorative board, which comprises impregnating a thin wood board with a photocurable resin obtained in combination with 0.1% or more of a photoreaction initiator and photocuring.