JP7183537B2 - foam wallpaper - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wallpaper that is used by sticking it to a wall surface in a room, and more particularly to a foamed wallpaper that is excellent in workability and that makes it difficult for unevenness to appear on the surface of the wallpaper after application.

Wallpaper is widely used as a decorative finishing material for interior walls of houses and shops. Various types of wallpapers are produced in terms of materials and designs. The wallpaper that is most commonly used is made by uniformly applying an expandable resin composition to the surface of a backing paper for wallpaper, heating it to gel once, applying a printing process, and then foaming it. The above is embossed, and is called a so-called foamed embossed wallpaper.

Since the foamed embossed wallpaper has a foamed resin layer, the weight per unit area can be reduced in spite of its thickness. For this reason, it is widely used because it requires less materials, is light and has good workability. (See Patent Document 1)

In the case of newly built homes and shops, the underlying surface is smooth and clean, but in the case of renovations, the backing paper of the old wallpaper remains partially on the underlying surface, and the traces of wood screws may remain on the underlying surface. Therefore, the construction surface is often uneven.

In the case of such an uneven construction surface, if you try to obtain a good finished surface, it is necessary to prepare the substrate, such as sealer treatment and putty repair, which takes a lot of time and effort, and the construction efficiency as a whole is poor. I had a problem.

Japanese Unexamined Patent Application Publication No. 2010-208302

The problem to be solved by the present invention is to propose a foamed embossed wallpaper that is less likely to cause irregularities on the underlying surface even when applied to an uneven underlying surface such as that seen during renovation.

As a means for solving the above problems, the invention according to claim 1 has a backing paper, a foamed resin layer, an ink layer, and a surface protective layer in this order, and an uneven pattern is formed on the surface. The surface roughness of the uneven pattern has a root-mean-square height (Sq) of more than 2.5 μm and not more than 3.2 μm , and a degree of deviation (Ssk) of −2.5 μm . A foamed wallpaper characterized by being less than 3 μm, having a maximum peak height (Sp) of greater than 40 μm and 70 μm or less , and a maximum valley depth (Sv) of greater than 240 μm and 270 μm or less. be.

In the foamed wallpaper according to the present invention, by specifying the surface roughness of the uneven pattern formed on the surface, the performance of hiding the unevenness of the base was ensured.

In the invention according to claim 2, the foamed resin layer contains an ethylene-vinyl acetate copolymer resin emulsion as a resin component, and is foamed using one or more of a microcapsule foaming agent and a chemical foaming agent. The foamed wallpaper according to claim 1, characterized in that it is a

In the invention according to claim 3, the ethylene-vinyl acetate copolymer resin emulsion has a glass transition temperature of −20° C. or more and 10° C. or less and a particle size of 0.4 μm or more and 0.9 μm or less. 3. The foamed wallpaper according to claim 2, wherein the non-volatile content is 50% or more and 75% or less.

The invention according to claim 4 is characterized in that the foamed resin layer contains 5 parts by weight or more and 35 parts by weight or less of a foaming agent with respect to 100 parts by weight of the ethylene-vinyl acetate copolymer resin emulsion. A foamed wallpaper according to claim 2 or 3.

By numerically specifying the surface roughness of the uneven pattern formed on the surface of the foamed wallpaper according to the present invention, the performance of hiding the unevenness of the base, which was not known until the actual construction in the past, is improved. Wallpaper can now be evaluated numerically. This is extremely significant in designing new wallpaper products and in manufacturing stable products.

As in the invention according to claim 2, the foamed resin layer has an ethylene-vinyl acetate copolymer resin emulsion as a resin component, and is foamed using one or more of a microcapsule foaming agent or a chemical foaming agent. In the case of , the burden on the global environment is small compared to conventional vinyl chloride resin wallpaper or the like using a large amount of plasticizer. Moreover, this combination can provide a sufficient expansion ratio, and better results can be obtained than mechanical foaming or the like.

As in the invention according to claim 3, the ethylene-vinyl acetate copolymer resin emulsion has a glass transition temperature of −20° C. or more and 10° C. or less and a particle size of 0.4 μm or more and 0.9 μm or less, When the non-volatile content is 50% or more and 75% or less, the necessary foaming performance can be obtained, and a more excellent product can be obtained in terms of the scratch resistance of the surface of the wallpaper.

As in the invention according to claim 4, when the foamed resin layer contains 5 parts by weight or more and 35 parts by weight or less of the foaming agent with respect to 100 parts by weight of the ethylene-vinyl acetate copolymer resin emulsion, The foamed wallpaper having the necessary surface roughness to ensure the performance of hiding the unevenness can be realized in a more stable state.

FIG. 1 is a cross-sectional explanatory diagram schematically showing the cross-sectional structure of the foamed wallpaper according to the present invention. FIG. 2 is a cross-sectional explanatory view schematically showing a method for evaluating the ability of the foamed wallpaper according to the present invention to hide unevenness of the base. FIG. 3 is a cross-sectional explanatory view schematically showing a state in which conventional wallpaper is evaluated by the same evaluation method as in FIG.

FIG. 1 is a cross-sectional explanatory view schematically showing the cross-sectional structure of foamed wallpaper 1 according to the present invention. The foamed wallpaper 1 according to the present invention is a foamed wallpaper having a backing paper 2, a foamed resin layer 3, an ink layer 4, and a surface protective layer 5 in this order, and having an uneven pattern 6 formed on the surface. The surface roughness of the uneven pattern 6 has a root-mean-square height (Sq) of more than 2.5 μm, a degree of deviation (Ssk) of less than 3 μm, and a maximum peak height (Sp) of more than 40 μm. and the maximum valley depth (Sv) is greater than 240 μm.

These surface roughnesses are surface roughness parameters defined in ISO25178, and can be measured with a contact or non-contact surface roughness meter. In recent years, non-contact surface roughness meters using lasers have made it possible to perform measurements in a short period of time, and have become fully applicable to quality control at production sites.

The root-mean-square height (Sq) is a parameter that corresponds to the standard deviation of the distance from the reference surface and corresponds to the standard deviation of height. When the Sq is 2.5 μm or less, the unevenness of the surface state is small and the uniformity is increased, so that the step of the base becomes conspicuous.

Skewness (Ssk) is a parameter representing the symmetry of the height distribution,
Ssk=0 indicates that the height distribution is vertically symmetrical, and Ssk>0 indicates a surface with many fine peaks. Ssk<0 indicates a surface with many fine valleys. The degree of bias should be less than 3 μm.

The maximum peak height (Sp) represents the maximum height of the surface from the reference surface . The maximum peak height must be greater than 40 μm, and if it is less than 40 μm, the step of the base becomes conspicuous.

The maximum valley depth (Sv) indicates the absolute value of the minimum height of the surface from the reference surface . The maximum valley depth must be greater than 240 μm, and if it is 240 μm or less, the step of the base becomes conspicuous.

Materials used for the foamed wallpaper according to the present invention will be described. As the backing paper 2, a general backing paper for wallpaper having a basis weight of about 60 g/m ² can be used. As the synthetic resin used for the foamed resin composition used to form the foamed resin layer 3, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin, acrylic resin, etc. are used. be done.

As foamed resin compositions, conventionally, oil-based resin compositions in which vinyl chloride resin (paste resin) is dispersed with a plasticizer such as a phthalate ester have often been used. Aqueous emulsions such as -vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin, and acrylic resin have been used more and more. Among these, the ethylene-vinyl acetate copolymer resin emulsion has a good balance between cost and performance and is most suitable for the purpose of the present invention.

When foamed wallpaper is produced using an ethylene-vinyl acetate copolymer resin emulsion, the glass transition temperature of the resin is preferably -20°C or higher and 10°C or lower, more preferably -15°C or lower. If the glass transition point temperature is high, a large amount of foaming agent must be blended to obtain the required expansion ratio, which is disadvantageous in terms of cost. Moreover, the particle diameter of the resin is desirably 0.4 μm or more and 0.9 μm or less, and the non-volatile content is desirably 50% or more and 75% or less.

When the ethylene-vinyl acetate copolymer resin emulsion satisfies the above properties, a foamed wallpaper having a better balance between scratch resistance and foamability can be obtained.

Other materials to be added to the foamed resin composition include foaming agents, foaming aids, fillers, pigments, dispersants, and the like. Mechanical foaming without using a foaming agent is available as a means of foaming resin, but using a chemical foaming agent or a microcapsule foaming agent is superior in terms of product stability, uniformity, expansion ratio, etc. .

Chemical blowing agents include azodicarbonamide (ADCA), dinitropentamethylenetetramine (DPT), and p,p'-oxybisbenzenesulfonylhydrazide (OBSH), which decompose and generate gas depending on temperature. etc. can be used.

As the microcapsule foaming agent, various products in which a volatile liquid such as a hydrocarbon is enclosed in microcapsules of a thermoplastic resin are commercially available. A microcapsule blowing agent may be used in combination with a chemical blowing agent. Microcapsule foaming agents are sometimes referred to as microspheres.

The foaming aid is used for the purpose of lowering the decomposition temperature of the foaming agent. For example, when the foaming agent is ADCA, a zinc compound or a urea-based compound is used as the foaming aid.

As for the amount of foaming agent added, for example, in the case of an ethylene-vinyl acetate copolymer resin emulsion, 5 parts by weight or more and 35 parts by weight or less can be added to 100 parts by weight of the emulsion. If it is less than 5 parts by weight, sufficient foaming cannot be expected, and if it exceeds 35 parts by weight, the surface of the foamed resin layer may be roughened and the printability may be impaired. It is also disadvantageous in terms of cost.

As fillers, white or colorless inorganic substances such as calcium carbonate, magnesium carbonate and silica are used. For example, in the case of an ethylene-vinyl acetate copolymer resin emulsion, 10 parts by weight or more and 100 parts by weight or less can be added to 100 parts by weight of the emulsion. Titanium oxide, iron oxide, carbon, organic pigments, and the like are used as the pigment, if necessary.

FIG. 2 is a cross-sectional explanatory view schematically showing a method for evaluating the ability of the foamed wallpaper according to the present invention to hide unevenness of the base. Moreover, FIG. 3 is a cross-sectional explanatory view schematically showing a state in which a conventional wallpaper is evaluated by the same evaluation method as in FIG.

A common gypsum board can be used as the flat base material 10 . Two tack seals 11 having a thickness of 100 μm are laminated on the surface of the gypsum board to reproduce a step of 200 μm. Wallpaper is applied on top of this, and visual evaluation is performed to evaluate the ability to hide the unevenness of the substrate. The foamed wallpaper 1 according to the present invention has an inconspicuous step as shown in FIG. 2, whereas the conventional wallpaper 20 has a noticeable step as shown in FIG. The foamed wallpaper according to the present invention will be described in more detail based on examples below.

<Example 1>
Wallpaper base paper (manufactured by KJ Specialty Paper Co., Ltd.) having a basis weight of 65 g/m ² was used as the backing paper. As the foamed resin layer, 100 parts by weight of an ethylene-vinyl acetate copolymer (EVA) resin emulsion (manufactured by Sumika Chemtex Co., Ltd. H-755HQ, Tg: -15 ° C.), a microcapsule foaming agent (manufactured by Matsumoto Yushi Co., Ltd. FT A foamed resin composition containing 16 parts by weight of -16) was applied, and after drying, a texture pattern was printed using water-based ink (Hydric manufactured by Dainichiseika Kogyo Co., Ltd.) to form an ink layer. At this point, it was confirmed whether or not there was any missing print, etc., and the surface properties of the original fabric were evaluated. After gravure-coating a water-based coating agent (Vinyblan 892 manufactured by Nissin Chemical Industry Co., Ltd.) as a surface protective layer on the ink layer, the ink layer was heated in an oven at 170° C. for 35 seconds to foam. Immediately after foaming, embossing was applied from the surface to prepare a foamed wallpaper. At this time, the expansion ratio was measured.

The surface roughness of the obtained foamed wallpaper was measured using a laser three-dimensional surface roughness meter. In addition, two sheets of tack seals with a thickness of 100 μm were pasted on top of each other, and then pasted using wallpaper glue on the surface of the gypsum board with a stepped base, and it was confirmed whether the step (unevenness) of the base was concealed. It was determined visually.

<Example 2>
Example 1 except that a resin having a Tg of 0° C. (H-7400HQ manufactured by Sumika Chemtex Co., Ltd.) was used as the ethylene-vinyl acetate copolymer (EVA) resin emulsion, and the amount of the foaming agent added was 32 parts by weight. A foamed wallpaper was prepared in the same manner as and evaluated in the same manner as in Example 1.

<Example 3>
Example 1 except that a resin having a Tg of 10° C. (S-355HQ manufactured by Sumika Chemtex Co., Ltd.) was used as the ethylene-vinyl acetate copolymer (EVA) resin emulsion, and the amount of the foaming agent added was 32 parts by weight. A foamed wallpaper was prepared in the same manner as and evaluated in the same manner as in Example 1.

<Comparative Example 1>
A foamed wallpaper was prepared and implemented in the same manner as in Example 1, except that a resin having a Tg of 0° C. (H-7400HQ manufactured by Sumika Chemtex Co., Ltd.) was used as the ethylene-vinyl acetate copolymer (EVA) resin emulsion. Evaluation was made in the same manner as in Example 1.

<Comparative Example 2>
A foamed wallpaper was prepared and implemented in the same manner as in Example 1, except that a resin having a Tg of 10° C. (S-355HQ manufactured by Sumika Chemtex Co., Ltd.) was used as the ethylene-vinyl acetate copolymer (EVA) resin emulsion. Evaluation was made in the same manner as in Example 1.

The above results are summarized in Table 1.

From the results in Table 1, the foamed wallpaper of Examples 1 to 3 has a root mean square height (Sq) of more than 2.5 μm and a bias degree (Ssk) of 3 μm for each parameter of surface roughness. The maximum peak height (Sp) is greater than 40 μm, and the maximum valley depth (Sv) is greater than 240 μm.

However, if the number of parts of the foaming agent is 32 parts, the surface properties of the original fabric will be poor, so care must be taken in selecting the pattern. Moreover, it is disadvantageous in terms of cost.

REFERENCE SIGNS LIST 1 Foamed wallpaper 2 Backing paper 3 Foamed resin layer 4 Ink layer 5 Surface protection layer 6 Uneven pattern 10 Base material 11 Tack Seal 20: conventional foam wallpaper

Claims (4)

A foamed wallpaper having a backing paper, a foamed resin layer, an ink layer, and a surface protective layer in this order, and having an uneven pattern formed on the surface, wherein the surface roughness of the uneven pattern is the root mean square The height (Sq) is greater than 2.5 μm and 3.2 μm or less , the degree of deviation (Ssk) is −2.5 μm or more and less than 3 μm, and the maximum peak height (Sp) is greater than 40 μm and 70 μm. and a maximum valley depth (Sv) of more than 240 μm and not more than 270 μm . 1. The foamed resin layer contains an ethylene-vinyl acetate copolymer resin emulsion as a resin component and is foamed using one or more of a microcapsule foaming agent and a chemical foaming agent. Foam wallpaper as described in . The ethylene-vinyl acetate copolymer resin emulsion has a glass transition temperature of −20° C. or more and 10° C. or less, a particle size of 0.4 μm or more and 0.9 μm or less, and a nonvolatile content of 50% or more and 75% or less. 3. Foamed wallpaper according to claim 2, characterized in that there is. 4. The foamed wallpaper according to claim 2, wherein the foamed resin layer contains 5 parts by weight or more and 35 parts by weight or less of a foaming agent with respect to 100 parts by weight of the ethylene-vinyl acetate copolymer resin emulsion.

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