JPS6230909B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a foam sheet and its manufacturing method,
More specifically, the present invention relates to a decorative foam sheet having an uneven pattern and excellent heat resistance and abrasion resistance, and a method for producing the same. Sheets of resinous compositions are widely used as decorative and anti-wear coatings on a variety of products. In particular, decorative foam sheets with textured surfaces have become widely used today due to their unique appearance, high degree of resiliency, and excellent tactility or texture, and their applications include floors, walls, and ceilings. covers, draperies, linings and clothing, tents,
This also applies to all other products that use plastic sheets. Among these, the flooring material is widely known as cushion flooring. Methods for manufacturing foam sheets with such uneven surfaces can be broadly divided into chemical embossing methods (for example, Japanese Patent Publication No. 43-28636 and Japanese Patent Publication No. 43-28636).
There are two types: the mechanical embossing method (see Publication No. 15713) and the mechanical embossing method. The chemical embossing method is an advantageous method compared to the mechanical embossing method because it does not require the use of an expensive molding roller and can produce a product with a molded surface that perfectly matches the printed pattern. Generally widely adopted. However, the products obtained by these methods have poor heat resistance, and especially in the case of cushion floors, if burn marks from cigarette burns remain, the aesthetic appearance of the flooring is impaired. Therefore, it has been desired to improve the heat resistance of foamable sheets. As a result of comparative studies of various methods, the present inventors found that by first forming a molded product with unevenness and then cross-linking and curing the surface, a foamed sheet with a clear uneven pattern and heat resistance can be obtained. I found out that it can be done. The present invention was completed based on this knowledge, and its gist is a foamed sheet consisting of a base material, a foamable layer, a printed layer, and a surface layer, the surface layer containing a polyfunctional monomer. The present invention relates to a foamed sheet made of polyvinyl chloride (hereinafter abbreviated as PVC) resin, which is characterized in that it is hardened by electron beam irradiation after forming an uneven shape on the sheet, and a method for producing the same. The foam sheet of the present invention has a crosslinked surface.
Since it is made of PVC, it is not only less likely to leave burn marks from cigarette burns than conventional cushion floors, but also has excellent abrasion and solvent resistance, and it also has the characteristics of a foamed product. The cushioning properties and appearance are not impaired in any way. The method for producing a foamed sheet of the present invention includes: (1) laminating a foaming layer on a base material, (2) forming a printing layer on the foaming layer, and (3) containing a polyfunctional monomer on the printing layer. After laminating the polyvinyl chloride resin composition, (4) forming irregularities simultaneously with or after foaming the foamable layer, and then (5) crosslinking the polyvinyl chloride by irradiating with an electron beam. (4) When a part of the printing layer contains a foaming suppressor or foaming accelerator, the formation of irregularities in the process is completed by the foaming of the foamable layer that occurs simultaneously with the heating gelation of PVC ( Special Publication No. 43-28636,
(See Japanese Patent Publication No. 46-4913 and Japanese Patent Publication No. 15713-1971). The pattern of the printing layer may be printed directly on the foam layer by gravure printing, rotary screen printing, etc., or may be printed on the back side of the PVC surface layer formed into a film. In some cases, it may be printed on a release paper and then transferred. Examples of the base material used in the present invention include base fabrics such as woven fabrics and nonwoven fabrics, paper materials, synthetic resin sheets, synthetic resin leather, and asbestos sheets. Specifically, as the paper material, commonly used papers such as kraft paper and Japanese paper are used. As the synthetic resin sheet, a foamed or non-foamed synthetic resin layer laminated on at least one side of various foamed or non-foamed synthetic resin films or paper materials is used. As the synthetic resin leather, a woven fabric, a non-woven fabric, or the like with a synthetic resin layer laminated on at least one side is used. The synthetic resin layer laminated here may be a multilayer or a single layer, and in the case of a multilayer, it may be a multilayer of either a foamed synthetic resin layer or a non-foamed synthetic resin layer, or a combination of both. A layered structure or a synthetic resin layer with glass fiber, glass mat, etc. submerged therein may be used. The foamable layer laminated on the base material is preferably a synthetic resin containing a foaming agent, such as a PVC resin.
As the blowing agent, any substance that produces bubbles when decomposed by heating can be used, and specific examples include dinitrosopentamethylenetetramine, N·N'-dimethyl-N·N'-dinitrosoterephthalamide,
Benzenesulfonylhydrazide, p-toluenesulfonylhydrazide, p・p′-oxybis(benzenesulfonylhydrazide), 3・3′-disulfonehydrazide diphenylsulfone, toluenedisulfonylhydrazide, p-toluenesulfonylhydrazone, p・p′-thiobis (benzenesulfonylhydrazide), toluenedisulfonylhydrazine, p-toluenesulfonyl azide, p-toluenesulfonyl semicarbazide, azobisisobutyronitrile, azodicarbonamide, diethyl azodicarboxylate, and the like. Foam suppressants that may be included in the printing layer include zinc oxide, zinc caprylate, zinc nitrate, zinc fatty acid soap, cadmium caprylate, cadmium caproate, cadmium fatty acid soap, lead carbonate,
Lead phthalate, lead phosphite, lead stearate, urea,
An example is borax. In addition, as foaming accelerators, maleic acid, maleic anhydride, fumaric acid, adipic acid, picolinic acid, salicylic acid, tetrachlorophthalic anhydride, trimellitic anhydride, terephthaloyl chloride, hydroquinone, 8-hydroxyquinoline, 1,8- Hydroxianthraquinone, diguanidine, acetoacetanilide, acetylacetone, alizarin, 2
Examples include -mercaptobenzothiazole and trimercaptotriazine. In the present invention, the polyfunctional monomer contained in the PVC resin composition of the surface layer refers to a monomer having two or more double bonds in the molecule, and specific examples thereof include divinylbenzene, diethyl glycol, divinyl ether, Ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate (however, those with a degree of polymerization of about 2 to 14 are preferred). Glycerin trimethacrylate, acrylic methacrylate, dimethacryl itaconate, dimethacryl malate, dimethacryl fumarate,
vinyl methacrylate, acrylic acrylate,
Examples include diisopropenyl diphenyl, trimethylolpropane trimethacrylate, tetramethylolmethanetetramethacrylate, 1,3-butylene glycol dimethacrylate, and aryl methacrylate, and two or more of these may be used in combination. These monomers are used in an amount of 3 to 50 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of PVC. If the amount of the monomer is less than 3 parts by weight, the heat resistance of the surface layer will hardly improve, while if it is more than 50 parts by weight, the sheet will become too hard after crosslinking and may easily cause cracks during transportation or construction in the winter. The polyvinyl chloride resin referred to in the present invention is a vinyl chloride homopolymer or a copolymer, preferably a homopolymer with an average degree of polymerization of 500 to 4,000, and a copolymer with an average degree of polymerization of 400 to 4,000. used. Copolymers include binary or more systems of vinyl chloride and monoethylenically unsaturated monomers copolymerizable with vinyl chloride (e.g., vinyl acetate, methyl acrylate, hinyl isobutyl ether, ethylene, propylene, etc.). A copolymer (including a graft polymer) containing at least 60% by weight of vinyl chloride is used. Furthermore, in the present invention, additives such as other known plasticizers, heat stabilizers for PVC processing, weather resistance stabilizers, colorants, surfactants, lubricants, diluents, fillers, etc. can be added to the PVC. It may be added to the resin composition to adjust hardness and the like. The dose of electron beam to crosslink the PVC resin surface layer is
Although it depends on the composition of the PVC resin composition and the desired physical properties of the resulting foam sheet, it is usually 1 to 10 Mrad.
It is. If the illumination exceeds 10 Mrad, the decomposition reaction caused by the electron beam will be greater, so even if the formulation is adjusted, it will be slow and will turn brown in 2 to 3 months. On the other hand, 1Mrad
In the following irradiation, the crosslinking reaction does not occur sufficiently, so that the heat resistance hardly improves. In addition, if the crosslinking reaction by electron beam is carried out in an atmosphere where oxygen exists, crosslinking damage prevention by oxygen and decomposition reaction of PVC by generated ozone will occur. Preferably, this is carried out in the presence of an oxygen barrier layer thereon. Oxygen barrier layers include peelable films (e.g., polyvinyl alcohol, acrylic acid and its derivatives, starch and its derivatives, cellulose, carboxymethyl cellulose, polystyrene, etc.), release materials (e.g., paper, nonwoven fabric, synthetic resin film-like substrates) materials made of silicone resin, polyvinyl alcohol, starch and its derivatives, paraffin, waxes, Teflon dispersion, etc.), floor polish materials, and floor sealing materials (for details on oxygen barrier layers, please refer to the special materials). (Refer to the specification of Application No. 146932/1983). Furthermore, if a polyfunctional monomer is supplied within the oxygen barrier layer and/or between the oxygen barrier layer and the surface layer and irradiated with an electron beam, the crosslinking density of the skin portion of the surface layer increases and the heat resistance of the surface layer increases. It can be further improved. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In each example, "middle part" indicates parts by weight unless otherwise specified. First, compositions 1 to 6 having the following compositions are prepared. Composition 1 PVC resin (Zeon 121, manufactured by Nippon Zeon Co., Ltd.)
same as below). 100 parts Dioctyl phthalate 60 parts Ba-Zn stabilizer 2 parts Zinc oxide 1 part Azodicarbonamide (foaming agent) 3.5 parts Composition 2 PVC resin 100 parts Dioctyl phthalate 50 parts Ba-Zn stabilizer 2 parts Pigment (white) : Titanium oxide, Yellow: Polyazo yellow,
Red: perylene red, blue: phthalocyanine blue, green: phthalocyanine green) 3 parts Composition 3 PVC resin 100 parts Dioctyl phthalate 50 parts Ba-Zn stabilizer 2 parts Trimethylolpropane trimethacrylate 10 parts Composition 4 PVC resin 100 parts Dioctyl Phthalate 50 parts Sn stabilizer 2 parts Trimercaptotriazine (crosslinking agent) 0.5 part Diazabicycloundecene-7 (crosslinking accelerator)
0.5 parts Composition 5 PVC resin 100 parts Dioctyl phthalate 50 parts Ba-Zn stabilizer 2 parts Benzoyl peroxide 1 part Diaryl phthalate 10 parts Composition 6 PVC resin 100 parts Dioctyl phthalate 50 parts Ba-Zn stabilizer 2 parts Pigment (Similar to that used in composition 2) 3 parts 2-mercaptobenzothiazole 3 parts Example 1 The plastisol of composition 1 was coated on asbestos paper with a thickness of about 0.5 mm to a thickness of 0.4 mm. ℃
The composition is gelled by heating for 1 hour. After cooling the gelled coating, a rotogravure printing machine prints a five-color pattern of Composition 2 on the gelled surface. Also,
Composition 6 containing 2-mercaptobenzothiazole, which is a foaming inhibitor, is used as a part of the printing composition. Organosol composition 3 containing polyfunctional monomers is then applied to the printed coating surface to form a uniform coating of 0.3 mm thickness and heated at 204° C. for 2 minutes to fuse each composition. By this heating, the foaming agent in Composition 1 is completely decomposed, and the composition layer has a thickness of 1.2 mm.
This results in a foamed layer, but recesses are formed in the areas where the composition 6 containing the foaming inhibitor is printed. After cooling the obtained foam molded product, in a nitrogen stream,
The PVC on the surface was crosslinked by 3 Mrad irradiation with an electron beam accelerated at 300 KV. Table 1 shows the physical properties and properties of the surface-cured foam molded product obtained. Comparative Example 1 In Example 1, instead of Composition 3, Composition 4 containing a crosslinking agent was uniformly coated as a surface layer with a thickness of 0.3 mm, and each composition was fused by heating at 204°C for 2 minutes. Completely crosslink with a crosslinking agent. The thickness of the foam layer is 0.7 mm, but Composition 6 containing a foam inhibitor
No recesses were formed in the printed areas. Table 1 shows the physical properties and properties of the molded product obtained. Comparative Example 2 Plastisol of Composition 1 was coated on asbestos paper with a thickness of about 0.5 mm to a thickness of 0.4 mm, and heated at 150°C.
for 1 minute to gel the composition. After cooling the gelled coating, a rotogravure printing machine prints a five-color pattern of Composition 2 on the gelled surface. Next, organosol composition 5 containing peroxide and polyfunctional monomer is applied to the printed coating surface to form a uniform coating with a thickness of 0.3 mm, and heated at 204° C. for 2 minutes to fuse each composition and cross-link it. Foam. Thereafter, irregularities are mechanically formed using an embossing roll corresponding to the pattern, and the material is cooled. Table 1 shows the physical properties and properties of the molded product obtained. Comparative Example 3 A foam molded product was produced in the same manner as in Example 1, except that the polyfunctional monomer was removed from Composition 3 of the surface layer and the electron beam irradiation was not performed. Table 1 shows the physical properties and properties of the obtained composition.

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Claims (1)

[Claims] 1. (1) A foamable layer is laminated on a base material, (2) a printed layer is formed on the foamable layer, and a portion of the printed layer contains a foaming suppressor or a foaming accelerator. (3) After laminating a polyvinyl chloride resin composition containing a polyfunctional monomer on the printing layer, (4) forming irregularities simultaneously with foaming of the foamable layer, and (5) irradiating with an electron beam. A method for producing a foam sheet comprising crosslinking polyvinyl chloride. 2. The manufacturing method according to claim 1, wherein the electron beam irradiation amount is 1 to 10 Mrad. 3. The manufacturing method according to claim 1 or 2, wherein the electron beam irradiation is performed in an inert gas atmosphere. 4. The manufacturing method according to any one of claims 1 to 3, wherein the electron beam irradiation is performed in the presence of an oxygen barrier layer on the polyvinyl chloride resin surface layer. 5. The manufacturing method according to claim 4, wherein the electron beam irradiation is performed by supplying a polyfunctional monomer within the oxygen barrier layer and/or between the oxygen barrier layer and the surface layer.