JPH0742095A - Copated paper for decorative laminate - Google Patents

Abstract

PURPOSE:To obtain a coated paper for decorative laminate having especially excellent gloss as well as excellent smoothness, surface strength, hiding power and printability. CONSTITUTION:This coated paper is produced by using a base paper having a surface strength of 15A to 32A in conformity to JIS P8129 and a smoothness of >=200sec in conformity to JIS P8119, coating the paper with a coating containing a filter and a binder to impregnate the resin component in the coating into the base paper and calendering the coated base paper. The coating is incorporated with 5-25 pts.wt. (based on 100 pts.wt. of the filler) of plastic pigment and/or binder pigment and the calendered paper has a glossiness of >=60% in conformity to JIS P8142.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated paper for a decorative sheet which is used for a building material or the like after printing, coating a surface protective agent if necessary, and adhering it to a substrate such as plywood. .

[0002]

2. Description of the Related Art As a veneer paper of this type, thin paper has been used for a long time, but in recent years, a base paper in which a resin is internally added to increase the basis weight of the paper to 30 g / m ² is used. It is also known. Furthermore, it is also known to add titanium dioxide in order to enhance the hiding property during printing.

On the other hand, Japanese Patent Laid-Open Nos. 63-190092 and 63-19
[0094] In the same manner, Japanese Patent Laid-Open Publication No. 1994-242242 discloses that papermaking or impregnation with a resin liquid after papermaking is performed.

When a conventional base paper for a decorative board is printed,
All of the smoothness, surface strength, hiding power and printing gloss are not sufficient, and there has been an urgent need to develop coated papers that satisfy these characteristics.

In order to meet these demands, the inventor of the present invention has disclosed that the surface strength defined by JIS P 8129 is 11 to 25 A and the smoothness defined by JIS P 8119 is 400 seconds as disclosed in JP-A-4-314538. As described above, a base paper having an air permeability of 30 to 80 seconds is coated with a coating material containing a filler and a binder, the resin component in the coating material is allowed to penetrate into the base paper, and a calendering treatment is performed on the base paper. The coating composition contains 14 to 20 parts by weight of SBR latex and 5 parts by weight or less of esterified starch per 100 parts by weight of the filler, and the coating amount is 8 to 25 g per one side.
/ M ² was taught to be desirable.

[0006]

However, the gloss of the coated paper for decorative boards disclosed in the publication is such that the gloss level defined by JIS P 8142 is about 50 to 58%, and the gloss level is higher depending on the application. May be required.

Therefore, an object of the present invention is to obtain a coated paper for a decorative sheet which is excellent in smoothness, surface strength, concealing property and printability, and which has particularly high white paper gloss and printing gloss.

[0008]

[Means for Solving the Problems] The above-mentioned problems are based on JIS P 8129.
The surface strength as specified in 15A to 32A and the smoothness as specified in JIS P 8119 of 200 seconds or more are coated with a paint containing a filler and a binder, and the resin component in the paint penetrates into the base paper. This can be solved by calendering and further containing at least one of plastic pigment and binder pigment in the paint in an amount of 5 to 25 parts by weight with respect to 100 parts by weight of the filler.

[0009] In addition, JIS P 8142 after calendar processing
It is preferable that the glossiness defined by is 60% or more.

[0010]

The present inventor investigated the glossiness by variously changing the conditions such as calendering in order to increase the glossiness of the blank paper. The glossiness can be increased to 60% or more by changing the kind of conditions. I found that I could not.

However, when at least one of the plastic pigment and the binder pigment is contained in the coating material in an amount of 5 to 25 parts by weight with respect to 100 parts by weight of the filler, a high white paper glossiness and printing glossiness can be obtained.

[0012]

The present invention will be described in more detail below. The inventor
It has been found that applying a paint containing a filler to a base paper having predetermined characteristics is particularly excellent in printability.

Furthermore, in this case, the requirements for the base paper are, in particular, surface strength, smoothness and air permeability.

The surface strength and smoothness are specified in JIS P 8129 and JIS P 8119. The surface strength is 15
It is set to A to 32 A, more preferably 23 A or more, and particularly preferably 25 A or more. The decorative plate may be peeled off after sticking an adhesive tape on its surface for a long time, and it is mainly desired that the decorative plate has high surface strength.

As means for increasing the surface strength, not only lowering the freeness but also adding a paper strength enhancer or the like can be added.

The smoothness is set to 200 seconds or more. According to the present invention, when the smoothness of the base paper is high, the smoothness becomes high when the coating material is blade-coated later, and the adhesion of the printing ink becomes good. On the contrary, when the smoothness is low, coating unevenness becomes large after coating.

The air permeability of the base paper is set to 30 to 300 seconds. High air permeability means that the base paper is highly dense, which prevents the ink vehicle from penetrating into the base paper.
The print will look good. As a means for increasing the air permeability, the L material is 80% or more in the pulp mixture,
Obtained by lowering the freeness. Freeness is 180-300cc, especially 200 at 30g / m ^2.
~ 250cc is preferred.

When the freeness is less than 180 cc, the drying property on the paper is deteriorated, and uneven glossiness due to uneven adhesion of the dryer occurs. Conversely, when the freeness exceeds 300 cc,
It is difficult to obtain the target paper strength. In case of 50g / m ² , 350cc ± 50
cc is preferred.

It is also desired that the base paper has a good texture. If there is unevenness in the formation of the base paper, it will cause uneven coating during coating, resulting in uneven printing. This is the same as the air permeability, the pulp content is 80% or more of L material,
Even if the material is blended, it is preferably 20% or less. When making base paper, in addition to paper strength enhancer, size fixer such as sulfuric acid band, pitch remover, rosin sizing agent, cationized starch (release accelerator from press rolls and wires, during drying) Functioning as a paper-strengthening agent), an antifoaming agent, etc. can be added. A filler such as titanium oxide may be added to this base paper. Papermaking can be carried out by a normal paper machine such as a Fourdrinier or a round net. Examples of the paper strengthening agent used here include polyacrylic amide resin, starch, polyamide epichlorohydrin resin, polyethyleneimine, and acrylic latex for internal addition. The paper strength enhancer is preferably 30 to 65 kg / Ton in dry weight, and particularly preferably 50 to 60 kg / Ton.

On the other hand, a coated paper for a decorative sheet can be obtained by applying a paint containing a filler and a binder to the base paper and calendering the paint. As the filler, clay, calcium carbonate light, calcium bicarbonate, titanium oxide, satin white and the like can be used.
As a binder, in order to increase the tape peeling strength (paper-to-paper strength) after cross-cutting, if necessary, P
VA is used. It is also effective to use it in combination with SBR latex. In this case, the binder is mixed with the filler 10
0 to 30 parts by weight as the total amount of binder 10 to 30
1 part by weight, more preferably 15 to 30 parts by weight, and set within the range of region X in FIG. Particularly preferred ranges are 2 to 5 parts by weight of PVA and 8 to 25 parts by weight of SBR latex (particularly preferably 14 to 22 parts by weight). In addition, 5 parts by weight or less of esterified starch and / or casein, especially 2 to
It is preferable to contain 5 parts by weight.

As the SBR latex, from the viewpoint of the adhesion between the nitrified cotton type ink and the coating layer, those having a large compounding ratio of acrylonitrile, particularly those having a compounding amount of 10 parts by weight or more are preferable.

Acrylonitrile has solvent resistance, and even if the ink vehicle penetrates into the coating layer, the latex polymer does not swell and the ink layer can be prevented from peeling off.

A water resistance agent, a lubricant, a defoaming agent, a water retention agent, a pH adjuster, a coloring pigment and the like can be further added to the paint. For coating, it is preferable to perform coating with a blade such as a tip blade or a vent blade. Roll coating,
Air knife coating and wire bar coating are also possible. The coating amount is preferably 8 to 25 g / m ² . If it is less than 8 g / m ² , good surface quality cannot be obtained, and the white paper gloss after supercalendering does not increase, resulting in a decrease in printing gloss and a decrease in paper strength. When the coating amount exceeds 25 g / m ² , the coating drying property becomes poor. On the other hand, the back side can be coated with an anti-curling oxidized starch, a preservative, a waterproofing agent and the like.

When the coating is completed, calendering treatment, particularly super calendering treatment, is performed. In this calendering process, the nip pressure is 145 to 250 kg / cm, although it depends slightly on the relationship with the grammage of the coated paper to be obtained.
² is preferable, and the number of nip steps is preferably 5 or more. If the nip pressure exceeds 250 kg / cm ² , the structure of the coating layer may be destroyed and the printability may deteriorate.

By the way, in high-end furniture, it is desirable that the high glossiness, that is, the glossiness defined by JIS P 8142 is 60% or more. Therefore, in the present invention, a plastic pigment or a binder pigment is used.
Of course, these can be used together.

Examples of plastic pigments (organic pigments) or binder pigments include styrene-butadiene polymer pigments, styrene pigments, styrene-acrylic pigments, and the like.
Further, a solid type, a donut type, a hollow type or the like can be used. The particle size of the pigment is 0.
1 to 2 μm is preferable. The binder pigment slightly hinders the development of gloss.

The amount of the plastic pigment or the binder pigment is 5 to 25 parts by weight with respect to 100 parts by weight of the filler. If the amount of addition is more than 25 parts by weight, so-called calendering occurs, especially after supercalendering, and the image quality is improved. Getting worse. On the contrary, if the amount is less than 5 parts by weight, the white paper and print glossiness cannot be 60% or more. 80% is sufficient as the upper limit of the white paper glossiness.

<Examples> The effects of the present invention will be clarified by showing Examples and Comparative Examples below. (Example 1) When the white paper glossiness and the printing glossiness were examined by the blending amount of the plastic pigment (PP: organic pigment) or the binder pigment (BP),
The results shown in Table 1 were obtained. In this example, SBR latex was used as the binder, clay: calcium carbonate = 80: 20 was used as the filler, and the coating amount was 15 g / m ² .

[0029]

[Table 1]

(Example 2) Further, when the product of the example of the present invention was compared with the conventional pigment-coated paper and the conventional inter-paper reinforcing paper, the results shown in Table 2 were obtained.

[0031]

[Table 2]

Example 3 As a filler, clay: calcium carbonate = 80: 20 parts by weight was used, and the respective amounts were investigated by changing the compounding amounts of SBR latex and PVA.
The results shown in Table 1 were obtained. The coating amount was 15 g / m ² . In the evaluation display, ⊚ is extremely good, ◯ is good, Δ is slightly inferior, and x is inferior. The display of this evaluation is the same in other tables.

[0033]

[Table 3]

Here, the cross-cut suitability means that after sticking to plywood, the coated surface is cut with a cutter knife so that the squares on the grid are 100 squares, cellophane tape is stuck to the surface, and the cellophane tape is peeled off. The evaluation is based on how many boxes are peeled off, and this is repeated 1 to 4 times to give an overall evaluation.

From these results, it was found that the coating layer containing a large amount of SBR latex and combined with PVA was excellent in both cellophane tape strength and cross-cut suitability. The evaluation is also shown in FIG.

[0036]

As described above, according to the present invention, smoothness,
Not only the surface strength, hiding power and printability but also the white paper gloss and the print gloss are excellent.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a preferable range of a blending ratio of a binder that can be used in the present invention.

Claims (2)

[Claims] 1. The surface strength specified by JIS P 8129 is 15A to
32A, a paper with a smoothness of 200 seconds or more specified by JIS P 8119, coated with a paint containing a filler and a binder, the resin component in the paint penetrated into the paper, and calendered. A coated paper for decorative sheet, characterized in that at least one of a plastic pigment and a binder pigment is contained in the paint in an amount of 5 to 25 parts by weight based on 100 parts by weight of the filler. 2. A coated paper for a decorative sheet, which has a glossiness of 60% or more as specified by JIS P 8142 after being calendered.