JPH0531444A - Pattern formation method - Google Patents

Abstract

PURPOSE:To easily form a desired pattern in a very short time on the surface of a substrate liable to deteriorate in irradiation with light. CONSTITUTION:When a discolored pattern is formed on the surface of a substrate which can be deteriorated and discolored by irradiation with light, the surface of the substrate is coated with a photosetting resin compsn. contg. a UV absorber except for a part corresponding to the pattern to be formed and then the substrate is irradiated with light to deteriorate and discolor the uncoated part of the substrate as well as to cure the resulting coating film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a pattern on the surface of a substrate which is easily deteriorated by irradiation with light.

[0002]

2. Description of the Related Art Generally, a paint or the like is applied to the surface of a base material to form a pattern on the base material. However, in the case where this base material is susceptible to deterioration and discoloration by light irradiation, such as long glass fiber reinforced rigid polyurethane foam, if the color after deterioration and discoloration is similar to the paint color, The pattern will gradually become unclear. In particular, it becomes remarkable when it is easily exposed to light due to outdoor use.

Therefore, conventionally, when forming a pattern on the surface of such a base material, first, an undercoat paint for preventing deterioration discoloration is applied to the surface of the base material in advance to form an underlayer. Was there. And on the surface of this underlayer,
Apply the paint for the top coat to form the desired pattern,
It was cured again, thereby forming the desired pattern on the substrate.

Since the base material of these paints is easily deteriorated by light irradiation, heat-curable paints and solvent-volatile paints have been used.

[0005]

However, in the case of the above-mentioned conventional method, a so-called undercoat for preventing deterioration discoloration and a so-called overcoat for forming a desired pattern are used.
This necessitates a process, which complicates the process and lengthens the coating time.

Further, when a heat-curable coating material is used, a high temperature and a long curing time are required, so that the heat resistance of the substrate must be increased.

Further, when a solvent volatilization type paint is used,
Since a highly volatile solvent such as cyclohexane or isopropyl acetate is used, it causes inconvenience to the environment of coating work.

The present invention has been made in view of the above circumstances, and provides a pattern forming method capable of easily forming a desired pattern in a very short time on the surface of a base material which is easily deteriorated by light irradiation. Is.

[0009]

The pattern forming method of the present invention for solving the above-mentioned problems is a method of forming a discolored pattern on the surface of a base material that can be deteriorated and discolored by light irradiation. A photocurable resin composition containing an ultraviolet absorber,
After being applied in the shape of the pattern to be formed, the base material is irradiated with light to cure the coating film, and the base material non-applied portion is deteriorated and discolored.

The substrate of the present invention, which is capable of being deteriorated and discolored by light irradiation, is not particularly limited, and long glass fiber reinforced rigid polyurethane foams used in building materials, agricultural spreading materials and various other parts. , Various materials such as wood, paper and plastic plate, plastic sheet can be used.

The photocurable resin composition used in the present invention contains a curable resin component, a photopolymerization initiator and an ultraviolet absorber as essential components.

As the curable resin component, as the photopolymerization initiator is activated by absorption of light, it is polymerized by this,
A resin component that cures. As this resin component, various types such as unsaturated polyester type, acrylic type, thiol / ene type and epoxy type can be used, but acrylic type is preferable from the viewpoint of weather resistance.

The acrylic type resin component is an acrylate oligomer having a molecular weight of several hundreds to several thousands in which an acryloyloxy group is bonded to the terminal of the skeleton of polyester type, urethane type, epoxy type, etc. , A monofunctional acrylate-based monomer or a polyfunctional acrylate-based monomer that imparts properties such as adhesiveness and fast curing property. The types and the mixing ratios of both are not particularly limited, and only one of them may be used, or a plurality of both may be mixed.

Examples of the monofunctional acrylate-based monomer include methyl (meth) acrylate (which represents methyl acrylate or methyl methacrylate; the same applies hereinafter), butyl (meth) acrylate, octyl (meth).
Aliphatic compounds such as acrylate, ether compounds such as methoxyethyl (meth) acrylate, carbitol (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, cyclic monomers such as phenoxy (meth) acrylate, 2 -Hydroxyethyl (meth) acrylate, a hydroxyl group-containing monomer such as 1,4-butanediol mono (meth) acrylate,
Others include 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl acid phosphate, dimethylaminoethyl (meth) acrylate and the like. In particular, methoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate and the like are preferably used because of their good adhesion.

Further, examples of the polyfunctional acrylate type monomer include hexanediol (meth) acrylate, neopentylglycol di (meth) acrylate, diethylene glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol ester (above bifunctional). ), Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate (above trifunctional), pentaerythritol tetra (meth)
Examples thereof include acrylate (above tetrafunctional) and dipentaerythritol hexa (meth) acrylate.

If the proportion of the monofunctional acrylate-based monomer in these acrylate-based monomers is less than 30% by weight, the wettability, lubricity and flexibility are deteriorated and the adhesiveness is deteriorated. It is necessary to contain, and preferably 50% by weight or more.

The photopolymerization initiator absorbs light having a wavelength in a specific range to generate active species and initiates the curing reaction of the curable resin component. The types thereof include radical polymerization type and cationic polymerization type, and among them, radical polymerization type initiators corresponding to acrylic type are preferable. In terms of the chemical structure, the radical polymerization type initiator may be an acetophenone type, a benzoin type, a benzophenone type, a thioxanthone type, or an acylphosphine oxide, a glyoxy ester, a diketone, or the like. The compounding amount is 0.1 to 1 with respect to the curable resin component.
It is preferably 0% by weight. The reason is that if it is less than 0.1% by weight, the curing of the resin component does not proceed satisfactorily, and if it exceeds 10% by weight, the curing of the resin component is hindered.

The ultraviolet absorber has a function of absorbing ultraviolet rays and preventing deterioration of the resin. As the ultraviolet absorber, for example, various types such as benzotriazole-based, benzophenone-based, benzoate-based, salicylate-based, and cyanoacrylate-based can be used.

The photocurable resin composition of the present invention contains, in addition to the above essential components, for example, hindered phenol-based, phosphorus-based, sulfur-based, amine-based antioxidants, colorants, and other leveling agents. Various components such as a filler can be appropriately added as needed.

As means for mixing and dispersing various components constituting the above photocurable resin composition, ultrasonic dispersion, three rolls, two rolls, kneader, sand mill, ball mill, dissolver, wing type stirrer, etc. are known. Is used.

As the method of applying the photocurable resin composition, a method of directly instilling the photocurable resin composition on a base material or a photocurable resin composition on a mold provided on the base material in advance A method of pouring the composition can be considered. Also, as a method of forming this form, a method of forming a film-like photosensitive resist, a method of forming by a printing method,
Examples thereof include a method of mounting a mold sheet on a base material and forming the same. Of these, screen printing is preferably used. That is, a screen printing plate having a pattern corresponding to a desired pattern is placed on a substrate, a resin for forming a pattern is applied on the substrate through the printing plate, and the resin is cured.

The above photocurable resin composition increases the amount of the ultraviolet absorber when the substrate is severely deteriorated,
It is preferable to apply the coating so that the coating film becomes thick.
However, in this case, since the photocurable resin composition is hard to cure, it is preferable to set the wavelength regions of the ultraviolet absorber and the photopolymerization initiator to be specific. That is, by making the wavelength region of the ultraviolet absorber and the photopolymerization initiator specific, it is possible to prevent the light from reaching the substrate by the ultraviolet absorber without inhibiting the photopolymerization by the photopolymerization initiator. You can In addition, even when the deterioration of the base material is not severe,
By simply applying the coating so that it becomes thicker, in addition to the deterioration and discoloration pattern, convex portions due to the coating are formed on the surface of the base material, and the pattern can have a three-dimensional effect.

As means for irradiating the base material with light to cure the coating film and means for discoloring and discoloring the base material, for example, conventional or high pressure mercury lamps, metal halide lamps, fluorescent lamps, xenon lamps, sunlight, etc. Known light sources can be used. In short, any material that emits light having a wavelength that activates the photopolymerization initiator can be used. As a result, the coating film of the photocurable resin composition is cured, and the base material is deteriorated and discolored.

[0024]

According to the present invention, a photocurable resin composition containing an ultraviolet absorber is applied to the surface of a base material which can be deteriorated and discolored by irradiation with light in the shape of the pattern to be formed, and then the base material Upon irradiation with light, the coating film is cured, the surface of the base material corresponding to the coating film is protected by the coating film and does not deteriorate and discolor, and the surface of the base material not covered by the coating film deteriorates and discolors. ..

[0025]

EXAMPLES Examples of the present invention will be described below.

[0026]

Example 1 100 μm on a 50 mesh screen
A non-printed portion was formed by a thick emulsion film to prepare a screen printing plate having an S-shaped pattern.

Then, using this screen printing plate, a photocurable resin composition was applied onto a long glass fiber reinforced rigid polyurethane foam (Slonneo Lumber FFU manufactured by Sekisui Chemical Co., Ltd.), and the printing plate was removed. From the height of 40 cm above the foam, irradiation was carried out for 1 minute with a high pressure mercury lamp with an input power of 80 w / cm. Then, the surface of the foam printed with the photocurable resin composition retained a pale yellow color, and the non-printed portion was changed from a pale dark color to a dark brown color. As a result, an S-shaped pattern was formed on the surface of the foam.

In this example, urethane acrylate (manufactured by Nippon Synthetic Chemical Co., Ltd.) was used as the curable resin component.
A mixture of 67 g of Gocelac UV-7500B) and 33 g of 2-hydroxypropyl acrylate, which was dissolved by heating, was added with 0.2 g of BHT. Then, 1 g of methylphenyl glyoxylate as a photopolymerization initiator and 0.3 g of 2- (5-methyl-2-hydroxyphenyl) benzotriazole as an ultraviolet absorber were added thereto.
and g were added to obtain a photocurable resin composition.

[0029]

Example 2 A form sheet was prepared by forming an S-shaped opening in a colorless and transparent silicone rubber sheet having a thickness of 1 mm.

Then, this form sheet was attached to a long glass fiber reinforced rigid polyurethane foam (made by Sekisui Chemical Co., Ltd.).
Eslon Neo-Lumber FFU), and the photocurable resin composition was introduced into the S-shape of the form sheet. Then, after curing the photocurable resin composition, the foam sheet surface corresponding to the S-shaped pattern retains a light yellow color by removing the form sheet, and the other portions retain a light dark color to a dark brown color. Discolored. As a result, an S-shaped pattern was formed on the surface of the foam, and a foam having a three-dimensional effect in which the S-shape was formed as a convex portion could be obtained.

[0031]

As described above, according to the present invention, a photocurable resin composition containing an ultraviolet absorber is applied to the surface of a substrate in the shape of the pattern to be formed, and then the substrate is exposed to light. By irradiation, the coating film is cured, the substrate surface corresponding to the coating film is protected by the coating film and does not deteriorate and discolor, and the substrate surface not covered by the coating film deteriorates and discolors. It is possible to easily form a clear pattern of the discolored portion and the non-discolored portion on the surface of the base material in an extremely short time.

Claims (1)

Claim: What is claimed is: 1. A surface of a base material which can be deteriorated and discolored by light irradiation.
A method of forming a discolored pattern, which comprises applying a photocurable resin composition containing an ultraviolet absorber to the surface of a base material in the shape of the pattern to be formed, and then irradiating the base material with light to form a coating film. A method for forming a pattern, characterized in that the base material is not cured and the uncoated portion of the base material is deteriorated and discolored.