JP2015081446A - Foam wallpaper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide foam wallpaper, excellent in a foaming state by resin cross-linking, without causing the problem such as the deterioration in lining paper and reduction in opportunity strength by an electron beam.SOLUTION: The foam wallpaper has a foam resin layer including an inorganic filler, a foaming agent and resin formed of ethylene only or copolymerized with other monomer on a paper base material, and has an irregular pattern on a surface. The foam resin layer is cross-linked by peroxide, and the peroxide includes 0.01-0.5 pts.wt. to 100 pts.wt. of resin in a foam resin layer, and also includes a trifunctional cross-linking assistant in the foam resin layer.

Description

  The present invention relates to a foam wallpaper that can be used for decorating wall surfaces of buildings such as detached houses, apartment houses, stores, and office buildings.

  As foamed wallpaper used for the above-mentioned applications, a paper base material in which a foamed resin layer of vinyl chloride resin is formed is known. In recent years, in consideration of the environment, a resin containing no halogen such as an olefin resin such as an ethylene-vinyl acetate copolymer resin has been used for the foamed resin layer.

  For example, a foamed resin composition in which a microcapsule-type foaming agent is added to an emulsion containing an ethylene-vinyl acetate copolymer is applied to a paper substrate and dried, then a pattern is printed on the surface, and then heated and foamed. Foamed wallpaper is known in which an uneven pattern is formed by an embossed plate. In addition, a foamed resin composition obtained by adding a thermally decomposable foaming agent to an ethylene-vinyl acetate copolymer is extruded and laminated on a paper substrate using a T-die extruder, a pattern is printed on the surface, and then heated. A foamed wallpaper is known which is foamed and has an uneven pattern formed by an embossed plate.

  However, in the case of an emulsion and a microcapsule type foaming agent, a large amount of energy is required to evaporate and dry the water of the emulsion. Moreover, the smoothness of the surface is inferior compared with the case where a chemical foaming agent is used. Also, when embossing, the shell of the microcapsule is strong, so the embossing may be insufficient, resulting in limitations on the design, and the non-land concealment during construction is likely to deteriorate. There is a problem.

  Also, in the case of a pyrolytic foaming agent and a T-die extruder, the flow rate of the T-die is slower and the residence time is longer at the end than at the center. Thermal degradation of raw materials is likely to proceed. Furthermore, vinyl acetate, the main raw material, corrodes the extruder, and the polarity of vinyl acetate acts excessively on inorganic filler components such as calcium carbonate and titanium dioxide, resulting in a thickening effect in the extruder. As a result, there are problems that cause film formation stability failure and abnormal torque and resin pressure. Moreover, there is a concern about deterioration over time due to hydrolysis of the ethylene-vinyl acetate copolymer.

  Further, Patent Document 4 relates to a production method in which a foaming agent-containing resin is directly heated and melt-extruded on a backing paper using a T-die extruder, the resin is crosslinked by electron beam irradiation, and then heated and foamed. There is a description. In this case, since the resin is cross-linked by the electron beam, a foamed wallpaper having fine foam cells and an excellent surface state can be obtained due to the effect of increasing the melt tension and molecular weight. However, in the wallpaper produced by the method of this document, since the electron beam irradiated to crosslink the resin partially reaches the backing paper, the cellulose on the backing paper deteriorates with an electron beam, resulting in a decrease in mechanical strength and yellowing. (This tendency is further increased by the thermal history received in the subsequent heating and foaming process). In particular, yellowing impairs the design of the wallpaper.

JP-A-6-47875 JP 2000-255011 A JP 2001-347611 A Japanese Patent No. 3923969

  The present invention has been made to solve this problem, that is, the problem is that the foamed state by the resin cross-linking is excellent, and the backing paper is deteriorated by electron beams and the opportunity strength is reduced. It is to provide a foam wallpaper without problems.

  The present invention solves this problem, that is, the invention according to claim 1 is a foamed resin containing a resin obtained by copolymerizing an inorganic filler, a foaming agent, ethylene alone or another monomer on a paper base material. A foam wallpaper having a layer and having a concavo-convex pattern on the surface, wherein the foam resin layer is crosslinked with a peroxide.

  The invention according to claim 2 is characterized in that the peroxide is contained in an amount of 0.01 to 0.5 parts by weight with respect to 100 parts by weight of the resin in the foamed resin layer. 1. The foam wallpaper according to 1.

  The invention according to claim 3 is the foamed wallpaper according to claim 1 or 2, wherein the foamed resin layer further contains a trifunctional crosslinking aid.

  The invention according to claim 4 is the foam wallpaper according to claim 3, wherein the crosslinking aid is triallyl isocyanurate.

  The foamed wallpaper of the present invention can be expected to have improved melt tension and improved gas retention because the resin component has a crosslinked structure due to the effect described in claim 1. This is advantageous in that the degree of crosslinking can be made uniform in the thickness direction as compared with other crosslinking methods such as crosslinking by electron beam irradiation. In crosslinking by electron beam irradiation, a difference occurs in the amount of penetration of the electron beam in the thickness direction. That is, the surface layer on the irradiation surface side has the highest irradiation amount, and the irradiation amount attenuates as it dives deeper. By increasing the acceleration voltage at the time of electron beam irradiation, it is possible to make the penetration amount in the depth direction almost uniform, but this means that the electron beam reaches the backing paper at a high irradiation amount. This leads to deterioration of the backing paper. On the other hand, in the thermal crosslinking using the peroxide as in the present invention, it is possible to make the degree of crosslinking uniform in the thickness direction. In addition, since the backing paper is not adversely affected, there is no problem due to deterioration of the backing paper. In addition, in the crosslinking by electron beam irradiation, the introduction cost burden of the electron beam irradiation apparatus is large, but the foamed wallpaper of the present invention is advantageous in that these costs are unnecessary. As described above, the foamed wallpaper of the present invention has many advantages as compared with the conventional foamed wallpaper subjected to electron beam irradiation.

  The foamed wallpaper of the present invention can obtain a suitable degree of crosslinking due to the effect described in claim 2. If the amount of peroxide added is less than 0.01 parts by weight relative to 100 parts by weight of the resin component of the foamed resin layer, a sufficient crosslinking effect cannot be obtained, and if more than 0.5 parts by weight Crosslinking is too advanced, and the expansion of the cell wall due to foaming is hindered.

  In addition, the foamed wallpaper of the present invention can more effectively cross-link the resin component due to the effects described in claims 3 and 4, and at the same time, can be expected to suppress the variation in material properties such as gel fraction. .

It is explanatory drawing which shows the structure of the cross section of one Example of the foam wallpaper by this invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows a cross-sectional structure of an embodiment of a foam wallpaper according to the present invention. It has a foamed resin layer 2 on a paper substrate 1 and is provided with an uneven pattern 3 on its surface. Moreover, the pattern layer 4 and the surface protective layer 5 are suitably provided.

The paper substrate 1 in the present invention can be used without limitation as long as it is usually used for what is called a conventional backing paper for wallpaper, and in particular, guanidine sulfamate and The preferred basis is a pulp-based flame retardant paper impregnated with a water-soluble flame retardant such as guanidine phosphate, or an inorganic paper mixed with an inorganic agent such as magnesium carbonate, aluminum hydroxide or magnesium hydroxide. As, it is 50-300 g / m < ² >, Preferably it is 60-160 g / m < ² >.

  Further, on the surface of the paper substrate 1, the surface on which the foamed resin layer 2 to be described later is provided is subjected to easy adhesion treatment such as corona discharge treatment, plasma treatment, ozone treatment, and / or acrylic-butyl copolymer. You may provide the easily bonding process layer (not shown) which apply | coated the polymer, the polyurethane which consists of isocyanate and a polyol, etc.

  As the foamed resin layer 2 in the present invention, ethylene alone containing an inorganic filler and a foaming agent or a resin copolymerized with another monomer is used. Specifically, in addition to polyethylene, ethylene-methyl methacrylate copolymer resin, ethylene-methacrylic acid copolymer resin, ethylene-acrylic acid copolymer resin, ethylene-vinyl acetate copolymer resin, and ionomer resin, ethylene alone or Resins copolymerized with other olefin monomers can also be used.

  Further, the foamed resin layer 2 in the present invention may be colored by adding a pigment or the like as necessary. The coloring by adding the pigment may be transparent, translucent, or opaque. For example, inorganic pigments such as titanium dioxide, iron oxide, carbon black, aniline black, phthalocyanine Organic pigments such as blue can be mentioned, and the amount of the pigment added is 5 to 50 parts by weight, preferably 10 to 30 parts by weight with respect to 100 parts by weight of the resin component. Moreover, well-known additives, such as a flame retardant, a cell regulator, a stabilizer, and a lubricant, can be used for the foamed resin layer 2.

  The resin used for the foamed resin layer 2 in the present invention is crosslinked by a peroxide. As the peroxide, a known radical generator that is decomposed by heating and generates free radicals to form crosslinks between or within the molecules can be used. For example, dicumyl peroxide, 1,1-ditertiarybutylperoxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-ditertiarybutylperoxyhexane, 2,5-dimethyl-2 , 5-ditertiarybutylperoxyhexyne, 1,3-bis (tertiarybutylperoxyisopropyl) benzene, tertiarybutylperoxyketone, tertiarybutylperoxybenzoate, and other organic peroxides. These crosslinking agents can be used alone or in admixture of two or more. The peroxide is preferably contained in an amount of 0.01 to 0.5 parts by weight with respect to 100 parts by weight of the resin in the foamed resin layer. If the amount of peroxide added is less than 0.01 parts by weight, a sufficient crosslinking effect cannot be obtained, and if it exceeds 0.5 parts by weight, crosslinking proceeds too much to inhibit cell wall elongation due to foaming. Therefore, both are not suitable.

  In the present invention, a trifunctional crosslinking aid may be further added to the foamed resin layer. Examples of crosslinking aids include polyunsaturated compounds such as polyallyl compounds and poly (meth) acryloxy compounds. For example, polyallyl compounds such as triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl fumarate, diallyl maleate, poly (meth) such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate Examples include acryloxy compounds and divinylbenzene, but in particular, triallyl isocyanurate can crosslink resin components more efficiently, and at the same time, it can be expected to suppress the variation in material properties such as gel fraction. Is preferred. These crosslinking aids can be used alone or in admixture of two or more. Although content of a crosslinking adjuvant is not limited, 10 weight part or less is preferable with respect to 100 weight part of resin in a foamed resin layer, and 0.1-3 weight part is more preferable.

  The uneven pattern 3 on the surface in the present invention is provided on the surface of the foamed resin layer 2 and is not particularly limited as a method of providing, but the surface side is cooled by utilizing the heat at the time of heating and foaming. A method of forming an uneven pattern on the surface by forming an embossing roll, setting the paper substrate 1 side as a rubber roll, niping with two rolls, and cooling (embossing) is preferable. As the concavo-convex pattern 3, for example, a wood grain plate conduit groove, a stone plate surface unevenness, a cloth surface texture, a satin texture, a grain, a hairline, a ridge groove, etc. are possible, and can be appropriately selected depending on the intended design. It is not limited.

  As the pattern layer 4 and the surface protective layer 5 provided as appropriate, known materials can be used. If the object of the present invention can be achieved, the pattern layer 4 and the surface protective layer 5 may not be provided. The pattern layer 4 and the surface protective layer 5 can be provided using a known printing technique such as gravure coating.

  As a paper substrate 1, a backing paper for wallpaper (manufactured by Kojin Co., Ltd .: WK-665IHT (trade name)) is used. Using a T-die with a hold, using a barrier type screw with a screw diameter (D) of 65 mm and L / D (screw length divided by screw diameter) = 32, using an extrusion lamination machine, a thickness of 100 μm single layer And provided by extrusion lamination. The extrusion conditions were set to 110 ° C. in all zones extending from the cylinder to the die.

  The paper base material 1 provided with the foamed resin layer 2 was heated at 140 ° C. for 30 minutes to allow the crosslinking to proceed. Thereafter, the surface of the foamed resin layer 2 was subjected to corona discharge treatment, and then a textile pattern was printed as a pattern layer 4 using a water-based ink by a gravure printing machine.

  Then, after heating at 220 ° C. for 40 seconds to foam the foaming agent, the metal roll (embossed plate) having a textured uneven pattern was pressed to form the uneven pattern 3, and the foamed wallpaper of Example 1 It was created. Moreover, the sample before shape | molding the uneven | corrugated pattern 3 for performance evaluation was also prepared.

  Using the same method as in Example 1 except that the materials listed in Table 2 were used instead of Table 1, foamed wallpaper of Examples 2 to 6 was obtained. Moreover, the sample before shape | molding the uneven | corrugated pattern 3 for performance evaluation was also prepared.

<Comparative Examples 1-9>
The foamed resin 2 was provided using the same method as in Example 1 except that the materials listed in Table 3 were used instead of Table 1, and the electron beam irradiation was performed from the foamed resin layer 2 side under the conditions shown in Table 4. I did it.

  After the corona discharge treatment was performed on the surface of the foamed resin layer 2 side, a textile pattern was printed as a pattern layer 4 using a water-based ink by a gravure printing machine. Next, after heating at 220 ° C. for 40 seconds to foam the foaming agent, a metal roll (embossed plate) having a textured uneven pattern was pressed to form the uneven pattern 3. Thereby, the foamed wallpaper of Comparative Examples 1-9 was obtained. Moreover, the sample before shape | molding the uneven | corrugated pattern 3 for performance evaluation was also prepared.

<Performance evaluation>
For the foamed wallpaper of Examples 1 to 6 and Comparative Examples 1 to 9, (1) foaming magnification, (2) foamed cell size, and (3) yellowing of the backing paper were evaluated. (1) Foaming ratio, (2) Foaming cell size was measured using a microscope “VHX-600” manufactured by Keyence Corporation for the sample before forming the concavo-convex pattern that had been sectioned using a razor blade (flat blade). Was used for observation. (1) The expansion ratio was defined by dividing the thickness after foaming by the thickness before foaming (= 100 μm). (2) The foam cell shape is a magnification of 100, and a cross section at an arbitrary position is shown on the display. Among the irregular shaped foam cells shown in the screen, the largest cell size is visually selected, and the foam cell The dimension of the portion perpendicular to the thickness direction was defined as a representative characteristic value. (3) The yellowing of the backing paper was determined by visual observation of the difference in discoloration before and after using the backing paper. The results are shown in Table 5.

  From the above results, the foamed wallpaper using the electron beam crosslinking of the comparative example can obtain a high foaming ratio and a fine foamed cell size depending on the conditions. It can be seen that the surface condition is poor due to the above and the yellowing of the backing paper has occurred. In addition to impairing the design properties, this also has a risk of accelerating deterioration over time. However, in the foamed wallpaper of the example, yellowing of the backing paper did not occur at all, and a foamed wallpaper with sufficient foaming and fine cells could be obtained.

  The foamed wallpaper of the present invention can be used for decorating wall surfaces of buildings such as detached houses, apartment houses, stores, and office buildings.

DESCRIPTION OF SYMBOLS 1 ... Paper base material 2 ... Foamed resin layer 3 ... Uneven pattern 4 ... Pattern layer 5 ... Surface protective layer

Claims (4)

  In a foamed wallpaper having a foamed resin layer containing an inorganic filler, a foaming agent, a resin copolymerized with ethylene alone or other monomers on a paper substrate, and having a concavo-convex pattern on the surface, the foamed resin A foam wallpaper characterized in that the layer is crosslinked with peroxide.   The foamed wallpaper according to claim 1, wherein the peroxide is contained in an amount of 0.01 to 0.5 parts by weight with respect to 100 parts by weight of the resin in the foamed resin layer.   The foamed wallpaper according to claim 1 or 2, further comprising a trifunctional crosslinking aid in the foamed resin layer.   The foamed wallpaper according to claim 3, wherein the crosslinking aid is triallyl isocyanurate.