JPS5824257B2 - Method for producing foam sheet with uneven pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a method for producing a foam sheet having a concavo-convex pattern, and more specifically, the invention relates to a method for producing a foam sheet having an uneven pattern, and more specifically, the invention relates to a method for producing a foam sheet having an uneven pattern. This invention relates to a method of manufacturing a foam sheet having irregularities that match the printed pattern by combining the above printing with printing.

Conventionally, as a method for manufacturing a foam sheet having an uneven pattern using ultraviolet irradiation, as shown in Japanese Patent Application Laid-Open No. 51-83661, polychlorination containing a reactive plasticizer, a blowing agent, and a photosensitizer is used. A method is known in which vinyl is partially irradiated with ultraviolet rays and then heated and foamed.

In this method, aluminum foil or the like with holes is used as a means for partially irradiating ultraviolet rays.

However, with the method of using aluminum foil with holes, etc., it is not possible to obtain a foam sheet that has a complicated uneven pattern, and furthermore, it is impossible to obtain a foam sheet that has an uneven pattern that matches the printed pattern. Met.

In order to improve the drawbacks of this conventional method, the present inventors created a pattern on the surface of a foamable synthetic resin sheet containing a UV crosslinkable resin using two or more types of prints with different UV transmittances. We have invented an improved method for obtaining a foam sheet with unevenness in accordance with a printed pattern or a foam sheet with complicated unevenness by heating and foaming it after irradiating it with ultraviolet rays.

However, in this improved method, when the foamable synthetic resin sheet is heated and foamed, convex portions are always formed in areas coated with paints with low UV transmittance (i.e. dark color printing liquid, white thread printing liquid, etc.). However, it was not possible to obtain a foam sheet having an uneven pattern in which the recesses were colored in a dark color or a white color.

Furthermore, it was not possible to print the concave portions in the same color as the convex portions.

The present invention provides a foam sheet having an uneven pattern in which the concave portions are colored in dark colors or white colors, which cannot be obtained by these conventional methods or improved methods thereof, and in which the concave portions are printed with the same color as the convex portions. It is an object of the present invention to provide a method for manufacturing a foam sheet having an uneven pattern, which allows obtaining a foam sheet having an uneven pattern.

In the present invention, a synthetic resin compound containing a predetermined amount of ultraviolet crosslinkable resin (including oligomer) and a photosensitizer, and a predetermined amount of a blowing agent is applied to the surface of a base material such as cloth, paper, or plastic film. A pudding solution containing an ultraviolet absorber and/or an ultraviolet shielding agent is applied on the surface of the liquid in a pattern pattern, and the synthetic resin layer is then irradiated with ultraviolet rays. However, in the area where the printing liquid is applied, the ultraviolet rays are absorbed with an ultraviolet absorber or the ultraviolet rays are blocked with an ultraviolet blocking agent to inhibit crosslinking and curing of the synthetic resin layer in that area, while in areas other than the area where the printing liquid is applied, By crosslinking and curing the synthetic resin layer, then printing with another print t-i on the areas to which a printing liquid containing at least an ultraviolet absorber and/or an ultraviolet shielding agent has not been applied, and then heating and foaming. , the area to which a printing liquid containing an ultraviolet absorber and/or ultraviolet shielding agent is applied is foamed to a predetermined thickness, and the area printed after ultraviolet irradiation is substantially inhibited from foaming and the foaming ratio is significantly reduced. This method produces an uneven pattern revealing sheet.

The foamable synthetic resin sheet used in the present invention is produced by applying a synthetic resin compound containing an ultraviolet crosslinkable resin, a photosensitizer, and a foaming agent onto a heat-resistant base material, and then gelling it by heating. can get.

Of course, a foaming aid may be included together with the foaming agent.

The synthetic resin used for the synthetic resin compound is preferably a thermoplastic synthetic resin such as vinyl chloride resin, and the synthetic resin compound containing a UV-curable resin, a photosensitizer, and a foaming agent is applied onto the base material. As a way to do this,
Although commonly used methods such as a calendar method, a doctor knife coater method, and a reverse roll coater method can be used, a method that finishes the surface of the applied synthetic resin compound as smooth as possible is preferred.

Base materials include woven fabrics, knitted fabrics, non-woven fabrics, paper, wood and metal plates,
In addition to glass plates, crow wool, plastic plates, plastic films, asbestos cloth, etc., those impregnated or coated with synthetic resins can also be used.

In addition to normal paper materials, release paper can also be used as the paper.

When a releasable base material such as release paper is used, the releasable base material must be peeled off at the end, but an uneven pattern revealing sheet without backing of the base material can be obtained.

Examples of UV-crosslinkable resins (including oligomers) used in the present invention include epoxy resins containing two or more epoxy groups in one molecule, such as bisphenol A epoxy resins, phenol novolac epoxy resins, and cresol novolak epoxy resins. Epoxy, acrylate resin, which is the reaction product of resin and unsaturated basic acid, reaction product of polyvalent cycloacetal compound and glycol unsaturated monocarboxylic acid monoester or polyhydric alcohol unsaturated monocarboxylic acid ester monool In addition to spiran resin and diallyl phthalate resin, various acrylic modified resins, methacrylic modified resins, oligoester acrylates, etc. can be used.

There is no particular need to remove monomers remaining during the production of these resins.

These ultraviolet crosslinkable resins may be used alone or in combination.

In addition, if the viscosity of the UV-crosslinkable resin is high, it may be diluted with a small amount of monomer before use. Diallyl phthalate, triallyl isocyanurate, tris-(2-nuccryloyl.

It can also be used diluted with small amounts of monomers such as (oxyethyl)-isocyanurate.

Examples of photosensitizers include benzoin methyl ether, benzine ethyl ether, benzoin isopropyl ether,
Commonly used photosensitizers such as benzoin alkyl ethers such as benzoin n-butyl ether and benzoin isobutyl ether, benzophenone, 5-nitrosoacenaphthene, N-acetyl, and benzyl can be used.

Further, a catalyst can be used together with a photosensitizer, and commonly used catalysts such as tertiary amines and metal compounds can be used as the catalyst.

A single type of photosensitizer can be used, or two or more types can be used in an appropriate combination.

The amount of the ultraviolet crosslinkable resin and/or monomer added is preferably 5 parts by weight to 100 parts by weight based on 100 parts by weight of Tanise resin.

The amount of the photosensitizer added is preferably 1% to 20% of the amount of the ultraviolet ray crosslinkable resin and/or 7-mer added.

It is also possible to use a combination of one or more photosensitizers and one or more catalysts.

In this case, the catalyst concentration is preferably 0.01 to 1%.

The ultraviolet absorbing liquid added to the printing liquid includes p-tertiarybutylphenyl salicylate, 2゜4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, and 2-hydroxy-4-benzyloxybenzophenone. 2-hydroxy-4-n-octoxybenzophenone, 2-(2'-hydroxy-4
'-n-octoxyphenyl)-benzo) l) Azole, 2-(3/, s/-alkyl-2'-hydroxyphenyl)-benzotriazole, 2-(hydroxy-5-tert-butylphenyl)-benzo Triazole, 2-(3',5'-ditertiary-butyl-2-
Commonly used ultraviolet absorbers such as (hydroxyphenyl)-benzotriazole can be used.

In addition, any UV shielding agent can be used as long as it makes the coating opaque, such as dark pigments such as carbon black, titanium white, antimony trioxide, calcium carbonate, talc, clay, silica, and other fillers. Can be used.

The printing liquid containing an ultraviolet absorber and/or an ultraviolet screening agent is prepared by dissolving one or more of the above-mentioned ultraviolet absorbers and/or one or more of the above-mentioned ultraviolet screening agents in a solvent. It is diluted and adjusted by adding resin, pigment and other additives as necessary.
It is okay to use a UV absorber and a UV shielding agent together.

The concentration of the ultraviolet absorber and/or ultraviolet shielding agent necessary to provide a good unevenness difference is preferably 1 to 75% by weight.

As the printing liquid used for printing after UV irradiation, in addition to commonly used printing liquids in which pigments and dyes are dispersed in liquid synthetic resin, printing liquids containing ultraviolet absorbers and/or ultraviolet shielding agents can also be used. .

The printing performed after UV irradiation may be monochrome printing or multicolor printing.

Further, if necessary, it is also possible to print with another printing liquid after the ultraviolet irradiation, overlapping the patterned area printed by the printing liquid containing an ultraviolet absorber and/or ultraviolet shielding agent applied before the ultraviolet irradiation.

Application methods for these printing liquids include gravure printing,
Printing using an intaglio roll, transfer, various screen printing, and spray painting can be applied.

In the present invention, a print t-i containing an ultraviolet blocking agent in the ultraviolet absorber is applied in a pattern on the surface of a foamable synthetic resin sheet containing an ultraviolet crosslinkable resin, a photosensitizer, and a catalyst. After irradiating this with ultraviolet rays, printing is performed on the part of the print l containing at least an ultraviolet absorber and/or an ultraviolet shielding agent outside the application part using another print g, and the part contained in the foamable synthetic resin sheet is printed. Since the foaming agent is heated above its decomposition temperature, the foamable synthetic resin sheet in the printed area applied with the printing liquid after irradiation with ultraviolet rays is
The degree of crosslinking is significantly higher than that of the area to which a printing liquid containing an ultraviolet absorber and/or ultraviolet shielding agent was applied prior to ultraviolet irradiation, so it does not melt even at temperatures above the decomposition temperature of the blowing agent and is substantially Since the foaming is suppressed and the foaming ratio is significantly lowered, the area where the printing liquid containing the ultraviolet absorber and/or ultraviolet shielding agent was applied will expand and form a convex part, but after the ultraviolet irradiation, the print I-l The printed portions do not foam and form concave portions, resulting in a foam sheet having concavities and convexities in accordance with the printed pattern.

In the present invention, the foam sheet having irregularities according to the printed pattern is a foam sheet having irregularities according to the printed pattern applied before UV irradiation, and the foam sheet having irregularities according to the printed pattern applied after UV irradiation. That's not what I mean.

Therefore, the method of the present invention is suitable for obtaining a foam sheet having a concavo-convex pattern that corresponds to the printed pattern as shown in FIG. 1, for example.

In the foam sheet having a concavo-convex pattern shown in FIG. 1, the bold line portion A forms a concave portion, and all other portions form convex portions of the same height.

The color scheme is as follows: the thick line part A is dark brown, the central circular interior is pale yellow with dark yellow dots, and the petal-shaped ground located diagonally of the middle square is dark orange. The inside of the petal shape is colored dark orange.

In addition, the inside of the V-shaped hole inside the medium square has dark yellow dots on a light yellow background, and the area surrounded by the external pressure square and the medium square has all pale yellow dots. The inside of the flower shape located diagonally is colored deep orange.

When attempting to obtain a foam sheet having irregularities in accordance with the printed pattern shown in Fig. 1 by a conventional method, first a foamable synthetic resin sheet containing a reactive plasticizer, a photosensitizer, and a foaming agent is prepared. It is necessary to leave only the thick line part shown in Figure 1 and cover the other parts with aluminum foil and irradiate the surface with ultraviolet rays, but covering with aluminum foil in this way is practically very difficult. It was difficult, and even if it were possible, it would not be practical.

In addition, according to an improved method separately invented by the present inventors, the thick line portion is foamed in the same way as the other portions, so the uneven pattern cannot be produced, and the foam sheet has an uneven pattern as shown in Fig. 1. It was impossible to obtain.

The present invention produces a foam sheet that has irregularities that match the printed pattern by combining printing with a printing liquid containing an ultraviolet absorber and/or ultraviolet shielding agent before irradiation with ultraviolet rays, irradiation with ultraviolet rays, and printing after irradiation with ultraviolet rays. In addition, it is possible to obtain a foam sheet having a concavo-convex pattern in which the concave portions are colored in an arbitrary color.

In the present invention, an ultraviolet crosslinkable resin is added to a foamable synthetic resin sheet, an ultraviolet absorber and/or an ultraviolet shielding agent is partially applied to this, the sheet is irradiated with ultraviolet rays, and then heated and foamed. Since the uneven pattern revealing sheet is manufactured using UV rays, it is superior in the following points to the method of obtaining an uneven pattern revealing sheet using a UV crosslinkable material instead of an ultraviolet crosslinkable resin. be.

■ If Nanatsuma was used, was there a risk that the monomer would volatilize during the manufacturing process (especially the foaming process) of the uneven pattern revealing sheet, resulting in deterioration of the manufacturing work environment or pollution? The monomer does not volatilize, and there is no risk of deteriorating the working environment or causing pollution.

■ When a monomer is used, unreacted residual particles remain in the areas where ultraviolet rays are blocked (curved areas of the uneven pattern revealing sheet), but in the case of the present invention, there is virtually no residual unreacted monomer. There is no product component due to unreacted monomer.

Furthermore, unreacted monomers cause rashes when they come into contact with the human body and are toxic, so it is undesirable for unreacted monomers to remain in the product.

Particularly when used in building materials such as wallpaper and flooring, the residual unreacted monomer is a decisive drawback.

■ When monomers are used, cross-linking of the monomers results in a highly reticulated structure, making the cross-linked parts hard and brittle, resulting in cracks or breaks when the product is bent or wound around a core. (This tendency is remarkable at low temperatures).

In the present invention, since a resin that can be cross-linked by ultraviolet rays is used, the cross-linked part is flexible without becoming hard or brittle, and there are no defects seen when using monomers. It is.

■ When a monomer is used, the monomer is cured in a short time by irradiation with ultraviolet rays, resulting in large volumetric shrinkage, making it impossible to obtain a good product.

In other words, when a non-shrinkable base material is used as the base material (
In the case of manufacturing paper-based wallpaper or asbestos sheet-based flooring materials, etc.), if the volumetric shrinkage is large, the product may curl, significantly reducing workability, or causing damage after construction. This causes peeling.

Also, if a shrinkable base material (cloth, etc.) is used as the base material,
Due to the shrinkage of the hardened part, the handle becomes deformed or wrinkled, which impairs the appearance of the product.

In contrast, the present invention provides a product with a beautiful appearance without such curling or shrinkage.

Examples are given below to explain the present invention in more detail.

Example 1 A foamable vinyl chloride paste compound having the following formulation is applied to paper to a thickness of 0.2w11 by a doctor knife coating method, and this is gelled by heating at 150° C. for 2 minutes to produce a foamable synthetic resin sheet.

Next, on the surface of the foamable synthetic resin sheet, Print M, which is made of the following formulation and contains an ultraviolet shielding agent (titanium oxide), is partially applied in an arbitrary pattern using a gravure printing method, and the Print M is heated to 80°C. After drying for 10 seconds with a condensing high-pressure mercury lamp (80 W/(b)), the area was irradiated with ultraviolet rays for 10 seconds, and the areas coated with printing liquid containing an ultraviolet blocking agent were colored red, blue, and yellow. A printed pattern was applied to print i, and print a colored black was printed on the area where the printing liquid containing the ultraviolet ray shielding agent was not applied, and after drying at 80°C for 10 seconds, it was heated to 200°C Heat for 1 minute to decompose the foaming agent contained in the foamable synthetic resin sheet.

The black printed part forms a recess, and the red, blue,
The yellow printed areas form convex portions of the same height, and the concave portions are colored in a dark color, and the printed pattern on the convex portions stands out clearly.This foam has unevenness. A body sheet was obtained.

In addition, the foaming ratio of the convex parts of this uneven pattern is 480%,
The foaming ratio of the concave portion was 100%, and the foaming suppression rate was 48%.

Foaming suppression rate is (foaming ratio of convex parts/foaming ratio of concave parts) x 100
When the value is 100, it indicates that foaming was not suppressed at all, and when the value is 100 or more, the larger the value, the greater the foaming suppressing effect.

[Brief explanation of the drawing]

Fig. 1 is a plan view of an example of a foam sheet having an uneven pattern obtained by the method of the present invention, and Fig. 2 is a plan view of an example of a foam sheet having an uneven pattern obtained by the method of the present invention.
This is a cross-sectional view taken along a line, in which 1 indicates paper and 2 indicates a foamed synthetic resin layer.

Claims (1)

[Claims] 1. A printing liquid containing an ultraviolet absorber and/or an ultraviolet shielding agent is applied in a pattern on the surface of a foamable synthetic resin sheet containing an ultraviolet crosslinkable resin and a photosensitizer, and then the foamable synthetic resin sheet is UV rays are irradiated onto the printing liquid coated surface of the foamable synthetic resin, and then the areas to which Pudding+4 containing at least an ultraviolet absorber and/or ultraviolet shielding agent is not coated are printed with another printing liquid, and then the foamable synthetic resin is A method for producing a foam sheet having an uneven pattern, which comprises heating and foaming the sheet.