JPH0531445A - Formation of pattern - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a pattern forming method for forming a desired pattern on a surface of a substrate that is easily deteriorated by light irradiation in an extremely short time and holding the pattern for a long time. [Structure] A method of forming a discolored pattern on a surface of a base material that is easily deteriorated by light irradiation, in which light is transmitted through a plate-shaped body having a light-transmitting portion corresponding to the pattern to be formed on the surface of the base material. After irradiating to cause deterioration and discoloration of the surface of the base material corresponding to the light-transmitting part, a photocurable resin composition containing an ultraviolet absorber is applied onto the base material, and the coating film is again irradiated with light to form the coating film. It cures.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a discolored pattern due to deterioration on a surface of a base material which is easily deteriorated by light irradiation.

[0002]

2. Description of the Related Art In general, a base material that is easily deteriorated by light irradiation,
For example, long glass fiber reinforced rigid polyurethane foam is
In particular, when used outdoors, it is eroded from the surface by the ultraviolet rays contained in sunlight and the wind and rain. as a result,
Deterioration in appearance due to yellowing and embossing of glass fibers,
Light transmittance is reduced.

Therefore, conventionally, in the case of forming a pattern on the surface of such a substrate, first, an undercoating paint having excellent weather resistance was previously applied to the surface of the substrate to form an underlayer. .. Then, on the surface of this base layer, a coating material for overcoating for forming a desired pattern was applied and 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 imparting weather resistance,
Two steps, so-called overcoating, for forming a desired pattern are required, which causes inconvenience that the steps are complicated and the coating time is long.

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 is a method for forming a pattern in which a desired pattern is formed in a very short time on a surface of a substrate which is easily deteriorated by light irradiation and the pattern is held for a long time. Is provided.

[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 substrate which is easily deteriorated by light irradiation. , After irradiating light through a plate-shaped body having a light-transmitting portion corresponding to the pattern to be formed and causing deterioration and discoloration of the surface of the base material corresponding to the light-transmitting portion, an ultraviolet absorber is contained on the base material. The photocurable resin composition is applied, and the coating film is cured by irradiation with light again.

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

The plate-like body having a light-transmitting portion used in the present invention can be formed, for example, by shielding a part of the light-transmitting plate-like material with a light-shielding substance and leaving a desired light-transmitting portion. it can.

As the method of forming the light-transmitting portion and the light-shielding portion, a method of printing a light-shielding paint on a light-transmissive plate, a method of sticking a sheet-shaped light-shielding substance to the light-transmissive plate, etc. Is mentioned. As another method, there is a method of printing a light-impermeable ink or the like on a light-transmissive plate in the form of fine dots or meshes.

The light-transmissive plate-like material may be a plate-like or film-like material that transmits light having a wavelength in a specific range, and more preferably 50% or more 100
The material must be capable of forming a light-shielding portion having a light transmittance of not more than%. Further, the larger the difference in light transmittance between the light shielding portion and the light transmitting portion, the better. More preferably, the light shielding part has a light transmittance of 10% or less of the light transmittance of the light transmitting part.

The light source for causing deterioration and color change may be under sunlight, but any light source that emits light having a wavelength of about 200 to 600 nm can be used. For example, any of a high pressure or ultra high pressure mercury lamp, a metal halide lamp, a fluorescent lamp, a xenon lamp, etc. can be used. The degree of deterioration and bleaching changes depending on the irradiation time of the light source, and the shade of the pattern is determined.

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 composed of an acrylate oligomer having a molecular weight of several hundred to several thousand and having an acryloyloxy group 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 (this 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-based 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 photocurable resin composition, ultrasonic dispersion, three rolls, two rolls, kneader, sand mill, ball mill, dissolver, wing type stirrer and the like are known. Is used.

There is no particular limitation on the method of applying the photocurable resin composition. Brush coating, flow coating,
Any known method such as dipping can be adopted.

The light source as means for curing is approximately 200 to 600 n, like the light source for forming the above pattern.
Any material that emits light having a wavelength of m can be used. For example, any of a high pressure or ultra high pressure mercury lamp, a metal halide lamp, a fluorescent lamp, a xenon lamp, sunlight, etc. can be used. In short, any material that emits light having a wavelength that activates the photopolymerization initiator can be used.

The above photocurable resin composition may increase 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, the ultraviolet absorber prevents the light from reaching the base material without inhibiting the photopolymerization by the photopolymerization initiator. You can Then, the coating film thus cured maintains the adhesiveness with the base material without promoting the deterioration of the base material. In particular, when the substrate is a long glass fiber reinforced rigid polyurethane foam, the cured coating film prevents the glass fibers from rising due to wind and rain erosion, and maintains excellent adhesion.

[0028]

According to the present invention, the surface of the base material corresponding to the transparent portion is deteriorated by irradiating the surface of the base material with light through the plate-like body having the transparent portion corresponding to the pattern to be formed. A pattern due to discoloration will be formed. In addition, a photocurable resin composition containing an ultraviolet absorber is applied onto this base material, and light irradiation is performed again, whereby the photocurable resin composition is formed in a state where a pattern due to deterioration discoloration is formed on the base material surface. Will form a coating film. Since the coating film contains an ultraviolet absorber, the effect of the ultraviolet absorber improves weather resistance, and as a result, the pattern of the base material, which is easily discolored by light irradiation, is not discolored. Even if the part is exposed, the pattern does not discolor, and the pattern is retained for a long time.

[0029]

EXAMPLES Hereinafter, one example of the present invention and comparative examples and reference examples to be compared therewith will be given to clarify the reason why the present invention is excellent.

[0030]

[Example 1] A Pyrex glass plate (trade name of Corning Glass Works) having a thickness of 4 mm was prepared as a light-transmissive plate, and a green oil-based ink was printed as a light-shielding substance on the surface of the glass plate to print light. A transparent portion and a light shielding portion are provided. Then, this glass plate was closely adhered onto a glass long fiber reinforced rigid polyurethane foam (Sekisui Chemical Co., Ltd. Eslon Neo-Lumber FFU), and 40 cm above the glass plate.
From the height of the high power mercury lamp with an input power of 80w / cm
Irradiated for minutes. Then, the surface of the base material facing the light transmitting portion was changed from pale yellow to dark brown, and a pattern was formed.

Then, the glass plate on the foam was removed, the photocurable resin composition was cast to a thickness of 0.5 mm, and again irradiated with a high pressure mercury lamp for 30 seconds to form a coating film.

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.

The properties of the obtained coating film and deterioration of the substrate
The fading state was observed.

Properties of the coating film The properties of the coating film are as follows. The cured coating film on the base material is divided into 25 pieces by cutting in a grid pattern, a tape is attached on the cured coating film, and then peeled off. The adhesion between the coating film and the substrate was measured by the number of coating films remaining on the substrate. The results are shown in Table 1.

Deterioration / Discoloration of Substrate After irradiating with a sunshine weather meter for 250 hours, the appearance is visually observed and a yellowing value ΔY1 of a non-patterned portion is measured with a multi-source spectrophotometer (manufactured by Suga Test Instruments Co., Ltd.). Was measured. The results are shown in Table 1.

[0036]

[Comparative Example 1] A cured coating film was formed in the same manner as in the above Example except that the ultraviolet absorber was not contained. Further, the properties of the obtained coating film and the deterioration / fading state of the substrate were observed.
The results are shown in Table 1.

[0037]

Reference Example 1 Table 1 shows the deterioration and fading state of the long glass fiber reinforced rigid polyurethane foam used as the substrate.

[0038]

[Table 1]

[0039]

As described above, according to the present invention, it is possible to form a pattern in a very short time by irradiation with light.
Further, by irradiating again with light, a coating film having excellent weather resistance can be formed, and the formed pattern can be retained for a long time without being discolored even under an exposed condition.

Claims (1)

Claim: What is claimed is: 1. A method of forming a discolored pattern on a surface of a base material which is easily deteriorated by light irradiation, the surface of the base material having a light-transmitting portion corresponding to the pattern to be formed. After irradiating light through the plate-like material to deteriorate and discolor the surface of the base material corresponding to the light-transmitting part, apply a photocurable resin composition containing an ultraviolet absorber on the base material, and light again. By irradiation,
A pattern forming method comprising curing the coating film.