JP3567059B2 - Base paper for decorative sheets - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides solid printing and pattern printing by a gravure printing machine, and sticks it to a base material such as plywood, particle board, medium density fiberboard (MDF) to form a decorative board, for building materials or for furniture. The present invention relates to a base sheet for decorative sheet for use as a surface material such as.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there are known two methods of an impregnated paper type decorative sheet, an after-impregnation method of impregnating after printing and a pre-impregnation method of printing on impregnated paper. However, papermaking and impregnation of base paper are often performed by paper makers, and distribution can be simplified, so that production by the pre-impregnation method is increasing.
In such a pre-impregnation method, the printability of the impregnated paper tends to be insufficient, and therefore, a smoothing treatment is performed by a super calender after the impregnation. However, in order to further improve the printability, a coating means is used. Has been considered.
[0003]
For example, Japanese Patent Publication No. 62-28238 proposes a method in which a pigment is coated after impregnation and a super calender treatment is performed. However, in this method, it is necessary to apply a sufficient amount to fill the unevenness of the surface before the application, and usually 5 g / m ² or more, preferably 8 g / m ² or more, unless the super coating is performed. The smoothing effect of the calender becomes insufficient.
Also, Japanese Patent Application Laid-Open No. 62-199002 proposes a method of clear coating only a resin liquid after impregnation and then performing a smoothing treatment. However, it also describes that the coating amount is preferably 5 g / m ² or more in this method.
[0004]
[Problems to be solved by the invention]
As described above, in order to improve the printability, it is necessary to apply a large amount of a coating agent and then smoothen it with a super calender or the like. Therefore, in addition to the drawback that the cost due to the coating agent increases and the cost of the drying equipment increases due to an increase in the amount of dry moisture, there is a problem that it is also necessary to take measures against contamination of the calender roll by calendering. there were.
[0005]
[Means for Solving the Problems]
The inventor of the present invention has conducted intensive studies in order to solve this problem, and as a result, when applying a coating agent containing a soft free emulsion resin having a glass transition temperature of 30 ° C. or less to impregnated paper having a smoothness of 200 seconds or more. It was found that the printability was good even with a small amount of coating agent, and the present invention was completed.
That is, according to the present invention, a soup-free emulsion resin having a glass transition temperature of 30 ° C. or less and a pigment in a ratio of 100: 0 to 15:85 are impregnated with a resin impregnated with 10% by weight or more and having a smoothness of 200 seconds or more. Is a base sheet for decorative sheet coated with a coating agent consisting of 1 to 5 g / m ² and a smoothness of 300 seconds or more.
[0006]
Hereinafter, the present invention will be described in detail.
The impregnated paper used in the present invention is a paper impregnated with 10% by weight or more of resin and having a smoothness of 200 seconds or more.
The impregnated paper is obtained by impregnating a base paper, which is made mainly of pulp with a pigment and a wet strength agent internally added, by an emulsion resin. The impregnation method may be any of a method of infiltrating with a size press or the like in-line after papermaking, and a method of dip-impregnating offline after temporarily drying and winding up the paper. Examples of the impregnating agent include acrylic ester-based, SBR (styrene-butadiene rubber) -based, and MBR (methyl methacrylate-butadiene rubber) -based emulsion resins, which can be used alone or in combination. Among them, an acrylate resin emulsion is preferred from the viewpoint of light resistance. The resin impregnation rate needs to be 10% by weight or more. When the amount is less than 10% by weight, the coating resin easily permeates. Not only a small amount of coating does not provide sufficient smoothness, but also the inter-paper strength becomes weak and the quality as a decorative sheet becomes insufficient. . Also, if the smoothness of the base paper before coating is low, the flatness after coating will be insufficient with a small amount of coating, so the smoothness needs to be 200 seconds or more. Smoothing is performed by a calender or the like.
[0007]
The emulsion resin for a coating agent used in the present invention must have a Tg of 30 ° C. or lower. Soap-free does not contain a low-molecular emulsifier as an emulsion stabilizer. As such a resin, an acrylic ester-based, SBR-based, or MBR-based soft-emulsion resin can be used, and these can be used alone or in combination. In addition, an acrylate-based emulsion is preferable from the viewpoint of light resistance.
When the Tg of the emulsion resin is higher than 30 ° C., the effect of improving printability is reduced.
[0008]
As the pigment used in the present invention, those usually used for pigment coating may be used, and examples thereof include clay, kaolin, and calcium carbonate.
If coloring is necessary, a coloring pigment such as iron oxide or an organic pigment may be used.
[0009]
The ratio between the emulsion resin and the pigment of the coating composition of the present invention is 100: 0 to 15:85. If the amount of the pigment is larger than this ratio, the surface strength of the base paper for decorative sheet becomes insufficient, which is not preferable.
[0010]
The coating amount of the coating agent (dry basis weight amount) of 1 to 5 g / ^{m 2,} preferably from 1 to 3 g / ^{m 2.} When the coating amount is less than 1 g / m ² , the flatness after coating is insufficient and the printability is not sufficiently improved, which is not preferable. If it exceeds 5 g / m ² , printability is sufficient, but it is not preferable in terms of cost.
[0011]
In the present invention, it is preferable to use a method which easily imparts flatness as a coating method of the coating agent, for example, a blade coating method, a reverse gravure coating method, or a general coating method. The smoothness can be made 300 seconds or more by the method using gingle.
[0012]
Hereinafter, the present invention will be described in detail with reference to examples.
Example 1
Colored pigments, wet strength agent added internally was 50 g / m ² base paper in an acrylic acid ester emulsion (manufactured by Nippon Zeon Co., Ltd., Nipo - Le LX814) after the impregnation 20 wt%, scan - Pa - Kyarenda - at smoothing And a 200 second impregnated paper was obtained. A styrene-butadiene resin soap emulsion having a Tg of 23 ° C. (Nipol SX1103, manufactured by Zeon Corporation) was coated on the impregnated paper so that the coating amount was 1 g / m ² . A base sheet for decorative sheet having a smoothness of 300 seconds was obtained.
Solid printing (THB41 yellow / TH04 white = 5/1) and gradation printing (THN13 red, THN41, THB41 yellow / TH04 white) were performed on this with a gravure printing machine, and the number of misdots in the highlight portion was counted. However, the number was 18 / cm ² and the printability by gravure printing was good.
[0013]
Comparative Example 1
In Example 1, a styrene-butadiene resin emulsion (Nipol LX433, manufactured by Zeon Corporation) having a Tg of 50 ° C. was used instead of an emulsion having a Tg of 23 ° C. as a coating resin. Was processed in the same manner as in Example 1 to obtain a base sheet for decorative sheet having a smoothness of 300 seconds.
This was subjected to a gravure printing machine in the same manner as in Example 1, and the number of misdots in the highlight portion was counted. As a result, the number was 58 / cm ² , and the printability in gravure printing was insufficient.
[0014]
Comparative Example 2
In Example 1, instead of an emulsion having a Tg of 23 ° C., an acrylic ester resin emulsion having a Tg of 21 ° C. (Nipol LX842, manufactured by Zeon Corporation) was used instead of the soap free as the coating resin. Except for the above, the same treatment as in Example 1 was performed to obtain a base sheet for decorative sheet having a smoothness of 300 seconds.
This was subjected to a gravure printing machine in the same manner as in Example 1, and the number of misdots in the highlight portion was counted. As a result, the number was 58 / cm ² , and the printability in gravure printing was insufficient.
[0015]
Example 2
Colored pigments, wet strength agent added internally was 60 g / m ² base paper in an acrylic acid ester emulsion (manufactured by Nippon Zeon Co., Ltd., Nipo - Le LX814) after a 15 wt% impregnation, scan - Pa - Kyarenda - at smoothing To obtain impregnated paper for 500 seconds. A styrene-butadiene resin soap free emulsion (Nipol SX 1103, manufactured by Zeon Corporation) / kaolin = 1: 1 with a Tg of 23 ° C. was applied to the impregnated paper so that the coating amount was 4 g / m ^2. By sgravure coating, a base sheet for decorative sheet having a smoothness of 600 seconds was obtained.
Gravure printing was performed in the same manner as in Example 1, and the number of misdots in the highlight portion was counted. The number was 8 / cm ² , and the printability in gravure printing was extremely good.
[0016]
Comparative Example 3
In Example 2, a gravure printing machine was used without coating, and the number of misdots in the highlight portion was counted. The number was 72 / cm ² , and the printability in gravure printing was insufficient.
[0017]
Comparative Example 4
The same procedure as in Example 2 was carried out except that the smoothness in the smoothing treatment by the super calender was changed to 150 seconds, to obtain a base sheet for decorative sheet having a smoothness of 200 seconds. A gravure printing machine was used in the same manner as in Example 1, and the number of misdots in the highlight portion was counted. The number was 53 / cm ² , and the printability in gravure printing was insufficient.
[0018]
Example 3
Colored pigments, wet strength agent added internally was 70 g / m ² base paper in an acrylic acid ester emulsion (manufactured by Nippon Zeon Co., Ltd., Nipo - Le LX814) after a 30 wt% impregnation, scan - Pa - Kyarenda - at smoothing After that, an impregnated paper for 800 seconds was obtained. A styrene-butadiene-based resin soap-emulsion (Nippon SX 1103, manufactured by Nippon Zeon Co.) / Acrylic ester-based resin soap-free emulsion (Nipol, Nippon Zeon) having a Tg of 23 ° C. (SX1706, Tg = 0 ° C.) = 1: 1 was subjected to reverse gravure coating at a coating amount of 2 g / m ² to obtain a base sheet for decorative sheet having a smoothness of 1200 seconds.
Gravure printing was performed in the same manner as in Example 1, and the number of misdots in the highlight portion was counted. The number was 3 / cm ² , and the printability in gravure printing was extremely good.
[0019]
Example 4
A 50 g / m ² base paper internally containing a coloring pigment and a wet paper strength agent is impregnated with 25% by weight of an acrylate ester emulsion (Nipol LX814, manufactured by Zeon Corporation) / urea resin = 9/1, and A smoothing treatment was performed with a par calender to obtain an impregnated paper for 400 seconds. A styrene-butadiene resin soap emulsion having a Tg of 23 ° C. (Nipol SX 1103, manufactured by Zeon Corporation) / calcium carbonate = 8: 2 was applied to this impregnated paper so that the coating amount became ² g / m ^2. -Coating was performed to obtain a base sheet for decorative sheet having a smoothness of 500 seconds.
Gravure printing was performed in the same manner as in Example 1, and the number of misdots in the highlight portion was counted. The number was 12 / cm ² , and the printability in gravure printing was extremely good.
[0020]
Comparative Example 5
The same procedure as in Example 4 was carried out except that the impregnation rate was changed to 8% by weight, to obtain a base sheet for decorative sheet having a smoothness of 250 seconds.
Gravure printing was performed in the same manner as in Example 1, and the number of misdots in the highlight portion was counted. The number was 48 / cm ² , and the printability in gravure printing was insufficient.
[0021]
【The invention's effect】
As described above, according to the present invention, a base sheet for decorative sheet is provided, which has a small amount of coating and is suitable for printing, especially with a small amount of coating.

Claims (3)

A coating agent comprising a soup-free emulsion resin having a glass transition temperature of 30 ° C. or less and a pigment in a ratio of 100: 0 to 15:85 on an impregnated paper having a smoothness of 200 seconds or more impregnated with a resin of 10% by weight or more. Is a base sheet for decorative sheet coated with a coating amount of 1 to 5 g / m ² and a smoothness of 300 seconds or more. 2. The base paper for decorative sheet according to claim 1, wherein the coating method of the coating agent is a blade coating method or a reverse gravure coating method. Preparative stencil - Cosmetic sheet according to claim 1 or 2, wherein the coating weight of 1 to 3 g / ^{m 2.}