JPH07331594A - Watrproof paper for decorative board - Google Patents

Abstract

PURPOSE:To obtain the waterproof coated paper for the decorative boards, using inexpensive paper as a raw material, excellent in moisture proofness and water proofness, good in processing characteristics for wrapping curved base materials with the paper and cutting the paper in a V-shaped form, and capable of giving the decorative boards having high grade appearances. CONSTITUTION:The waterproof coated paper for the decorative boards is obtained by coating a clear waterproof resin not containing a filler in a dry weight of 5-25g/m<2> on at least one side of a raw paper sheet having a surface strength of 15-32A defined by JIS P 8129 and a smoothness degree of >=200 see defined by JIS P 8119.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to waterproof coated paper for decorative boards. More specifically, the present invention is
The present invention relates to a waterproof coated paper used for a decorative material such as a laminated plywood used for a building material used in a sanitary room such as a bathroom, a dressing room and a washroom, a kitchen, and a kitchen cabinet.

[0002]

2. Description of the Related Art Sanitary rooms, wall boards used in kitchens, crosspieces, storage panels, kitchen cabinets, etc. are required to have moisture-proof and water-proof properties because they easily condense and get wet. Is used. In recent years, along with changes in lifestyles and diversification of needs, general decorative boards such as wall boards for living rooms and furniture have a high-class feeling, and high-quality ones that have a feeling of enriching life. Is being sought. In addition, from the viewpoint of total harmony of houses, wall panels used for sanitary rooms, kitchens, crosspieces, storage panels, and kitchen cabinets have the same high-class feeling as living room wall panels, furniture, etc. Therefore, there is a demand for high-quality products having a feeling of enriching life. For that purpose, a moisture-proof and waterproof decorative board is suitable. However, both the particle board and the medium-quality fiberboard (MDF), which are the base materials of the decorative board, have poor moisture-proof and waterproof properties, and swell when absorbing water, curling or forming mold, and cannot be used as they are. . Therefore, the sanitary room,
Of the wall panels used in the kitchen, crosspieces, storage cabinets, and kitchen cabinets,
As a moisture-proof / water-proof decorative board, vinyl chloride, etc., which is printed on a base material such as plywood, particle board, MDF, etc., which is the same as those currently used for living room wall boards, furniture, etc. A decorative plate or a V-cut plywood laminated with a film for decorative plate consisting of or a decorative plate lapped by a wrapping machine is used. A decorative film made of printed vinyl chloride, etc., is highly moisture-proof and waterproof, and it can follow the pressure roll of a wrapping machine well when laminating to a curved substrate. Not limited to this, it is also widely used for decorative boards for curved shapes. However, vinyl chloride has a high material cost, and there are limits to the inks that can be used for printing, and there is a limit to producing a high-class feel. Although vinyl chloride is printed by a gravure printing method, in order to prevent the occurrence of troubles due to deterioration of dimensional stability of the vinyl chloride film due to heating in the drying process after printing, printing
Productivity is low because the drying speed must be suppressed and the speed cannot be increased. In addition, there is a drawback that harmful gas is generated during combustion.

By the way, as the veneer paper, (a) a base paper internally added with a resin, (b) a paper impregnated with a resin at the time of papermaking or after papermaking (Japanese Patent Laid-Open No. 191922/1988). JP-A-63-190094) is known. Paper is inexpensive, can be used in various printing methods, and has a wide range of printing inks that can be used for high-quality printing. Adhesiveness to the surface of a substrate made of plywood, particle board, MDF, etc. It is much better than vinyl chloride. However,
In addition to lacking in waterproofness, even if a paper printed and top-coated is used, water infiltrates from the top-coat layer, the particle board and MDF swell, and curls or mold occurs. In addition, when the pressure roll of the lapping machine presses the concave portion of the curved surface-shaped substrate in the laminating process to the curved surface-shaped substrate, the bending resistance and the inter-paper strength are insufficient, so cracks, cracks, crevices, etc. occur. When used as a decorative plate, it is easily fluffed or damaged due to friction or the like. Therefore, the conventional veneer paper of this type is merely used as a veneer for a planar shape such as a ceiling by being bonded to a plywood or the like.

As a result of earnest research, the inventor of this application has already invented a coated paper for a decorative sheet having good printability (see Japanese Patent Laid-Open No. 4-314538). However, it cannot be said that the coated paper for decorative sheet has sufficient moisture proof / waterproof property, bending resistance, and interpaper strength.
Therefore, in addition to being inexpensive paper, capable of high-quality printing, it is also excellent in moisture-proof / water-proof, bending resistance, and paper-to-paper strength, and is a V-cut plywood and a decorative board that can be processed by a lapping machine. The development of suitable ones was sought after.

[0005]

SUMMARY OF THE INVENTION The present invention was devised in view of the above circumstances and uses inexpensive paper as a material, has excellent moisture-proof and waterproof properties, and wraps a curved surface-shaped substrate. It is an object of the present invention to provide a waterproof coated paper for a decorative sheet, which has a good V-cut processing property and can obtain a high-quality decorative sheet.

[0006]

[Means for Solving the Problems]
8129 has a surface strength of 15 to 32 A, and J
It was achieved by coating a clear waterproof resin containing no filler with a dry weight of 5 to 25 g / m ^{2 on} at least one side of a base paper having a smoothness of 200 seconds or more as defined by ISP 8119.

As a material satisfying the conditions of the base paper used in the present invention, the pulp blending ratio; L-BKP is 80 to 1.
00%, N-BKP 0-20%, freeness; 180
It is preferable to use one having a size of up to 350 cc. Freeness of 200 to 310 cc is particularly desirable. NB
If the KP exceeds 20%, the texture will be poor and uneven coating will occur during coating, resulting in uneven printing. If the freeness is less than 180 cc,
Drainage of water, poor drying property, uneven adhesion of the dryer, and uneven gloss. On the contrary, if the freeness exceeds 350 cc, sufficient inter-paper strength cannot be obtained.
The freeness is preferably in the above range in view of the coating property of the clear waterproof resin component described below on the surface of the base paper, the balance of the inter-paper strength, and the like.

Among the chemicals to be added internally to the pulp liquid, cationic starch, polyacrylic amide resin, polyamide epichlorohydrin resin and the like can be used as the paper strength enhancer. In particular, the cationized starch also functions as a wire peeling accelerator. The addition amount is
DRY of 30 to 65 kg / T is preferable, and an addition amount of DRY of 50 to 60 kg / T is particularly desirable in order to increase the strength between sheets. In addition, a size fixing agent such as a sulfuric acid band, a pitch remover, a rosin sizing agent (saponification type, emulsion type), a defoaming agent, and a filler such as titanium oxide can be added to the pulp liquid.

The pulp liquor can be produced by a conventional fourdrinier paper machine, twin wire paper machine, or round net paper machine. Then, it is dried by a Yankee dryer or a multi-cylinder dryer to a moisture content of about 4.0%.

It is preferable that the base paper has a surface strength of 15 to 32 A and a smoothness of 200 seconds or more. When the surface strength is in the range of 15 to 32 A, in combination with the below-mentioned clear waterproof resin coated on the base paper, cracks, cracks, cracks, etc. do not occur even when pressed by the roll of the lapping machine, and V cut It has sufficient bending resistance against bending for plywood. In addition, high-grade decorative boards used for kitchen cabinets and the like are required to have sufficient strength against tape peeling strength (paper-to-paper strength) after cross cutting. In order to satisfy such tape peeling strength, it is desirable that the base paper has a surface strength of 20 to 32 A. Further, when the smoothness is 200 seconds or more, the below-mentioned clear waterproof resin liquid can be uniformly applied. When the smoothness is less than 200 seconds, uneven coating of the clear waterproof resin liquid described below occurs, which causes uneven printing later, which is not preferable. The smoothness of the base paper may be any smoothness that allows the clear waterproof resin liquid to be uniformly applied to the base paper, and the upper limit is not particularly limited. However, when using papermaking / dried base paper, it is possible to use base paper for up to 500 seconds, which is the technical limit, and 8 for super calendered base paper.
Anything up to 00 seconds can be used. A base paper having a smoothness exceeding this range is not preferable because the transferability of the clear waterproof resin liquid to the base paper during coating is poor and, as a result, coating unevenness is likely to occur.

The clear waterproof resin used in the present invention is at least soap-free emulsion polymerization S.
Any one of BR latex, soap-free emulsion-polymerized NBR latex, and soap-free emulsion-polymerized MBR latex can be used. Soap-free emulsion polymerization refers to polymerization in which a reactive emulsifier is used and the emulsifier reacts with the polymer produced at the end of the emulsion polymerization and is incorporated into the polymer molecule. For soap-free emulsion polymerization of latex, it is preferable to use a reactive allyl alcohol derivative emulsifier. By using soap-free emulsion-polymerized SBR latex, soap-free emulsion-polymerized NBR latex, and soap-free emulsion-polymerized MBR latex, moisture-proof and waterproof functions can be imparted. On the other hand, soap-free emulsion-free SB
In R latex, NBR latex, and MBR latex, an emulsifier is present and absorbs water, so that the moisture-proof and waterproof functions are not sufficient, which is not preferable. Further, as the clear waterproof resin, at least internally cross-linked SBR latex, internally cross-linked NBR latex, internally cross-linked MBR latex, self-cross-linked SBR latex,
Either a self-crosslinked NBR latex or a self-crosslinked MBR latex can be used. The internally cross-linked SBR latex, the internally cross-linked NBR latex and the internally cross-linked MBR latex can be obtained by internally cross-linking the SBR latex, the NBR latex and the MBR latex with an internal cross-linking agent. Internal swelling is suppressed by increasing the internal density of the polymer (increasing the molecular weight) by internal crosslinking,
The moisture-proof and waterproof functions can be improved. Divinylbenzene (DVB) is preferably used as the internal cross-linking agent. The self-crosslinked SBR latex, self-crosslinked NBR latex, and self-crosslinked MBR latex can be obtained by self-crosslinking SBR latex, NBR latex, and MBR latex with a self-crosslinking agent. The self-crosslinking agent can accelerate the film formation by causing a crosslinking reaction during film formation, thereby improving the moistureproof / waterproof function. As a self-crosslinking agent, n-methylol acrylamide (n-MAM) and glycidyl methacrylate (GMA) are preferable. These clear waterproof resins can be used alone or in combination, and they are applicable products, that is, sanitary rooms, wall boards used in kitchens, crosspieces, storage panels, kitchen cabinets, etc. It is appropriately determined according to the required quality (paper strength, bending strength, etc.).

The clear waterproof resin made of the above-mentioned materials can be used for the roll coater method, the air knife coater method,
A known coating method such as a blade coater method or a bar coater method is used to supply and coat at least one surface of the base paper. Of these, the blade coater method from the viewpoint of the smoothness of the coated surface,
The tip blade method and the bent blade method are particularly preferable. By this method, the clear waterproof resin is applied to the base paper so that the dry weight is 5 to 25 g / m ² ,
Obtain waterproof coated paper for veneer. If the dry weight of the clear waterproof resin is less than 5 g / m ² , the surface of the base paper cannot be uniformly covered and coating unevenness occurs, resulting in insufficient moisture resistance and waterproofness. Conversely, 25g
If it exceeds / m ² , the drying property after coating will be poor and the coating speed will be slow, leading to higher costs. If necessary, a known oxidized starch for curling prevention, a preservative, and a water-proofing agent can be coated on the back surface of the base paper. And, as a matter of course, the clear waterproof resin liquid may be applied on both sides.

Further, after coating with a clear waterproof resin liquid and drying, a pigment consisting of titanium, clay, and calcium carbonate is formed on at least one surface of the waterproof coated paper for decorative plate in order to improve printing characteristics such as ink receptivity. It can also be coated. As the pigment coating agent, titanium, clay, calcium carbonate alone, or a mixture thereof is used. These pigment coating liquids are supplied to the surface of the waterproof coated paper for decorative sheet by a known coating method such as a roll coater method, an air knife coater method, a blade coater method and a bar coater method to form a coating layer.

When printing gloss is required, it is preferable to carry out a super calendar treatment. The nip pressure or the number of nip steps of the super calendar is appropriately changed according to the required glossiness, but normally, the nip pressure is preferably 145 to 250 kg / cm, and the number of nip steps is preferably 5 or more. After that, print it,
Further, if necessary, a surface protective material is coated by a known method,
It is possible to obtain a waterproof coated paper product for printed veneer boards, which is extremely moisture-proof and waterproof. Then, this is laminated on a base material such as plywood or lapped by a lapping machine to produce a moisture-proof and waterproof decorative board, which is used as a building material or the like that requires moisture-proof and waterproof properties.

[0015]

Function: A clear waterproof resin containing no filler in dry weight on at least one side of the base paper having a surface strength of 15 to 32 A specified by JIS P 8129 and a smoothness of 200 seconds or more specified by JIS P8119. 5-25
Waterproof coated paper for veneer coated with g / m ² is excellent in moisture resistance / waterproofness, bending resistance, paper strength, smoothness, printing gloss, ink acceptance, and moisture resistance by V-cut plywood and wrapping machine. -Suitable for manufacturing waterproof decorative boards.

[0016]

The present invention will be described in more detail with reference to the following examples. Of course, the present invention is not limited to the following examples. (Example 1) L-BKP 100%, freeness 200
cc, polyacrylic amide paper strengthening agent DRY46
A Kg / T pulp liquid was made with a Fourdrinier paper machine at a papermaking speed of 200 m / min to obtain a base paper having a surface strength of 23 A, a smoothness of 410 seconds, and a tsubo of 30 g / m ² . Soap-free emulsion polymerization SB
R latex (trade name Pateracor SB-302, manufactured by Dainippon Ink & Chemicals, Inc.) was coated on one side of the base paper with a vent blade coater at an application amount (dry weight) of 10 g / m ² on an off machine. Then, the coated surface was supercalendered at a speed of 500 m / min and a nip pressure of 1
It was treated under the conditions of 45 kg / cm and a roll temperature of 40 ° C. to obtain a waterproof coated paper for decorative board. The obtained waterproof coated paper for decorative board was lapped on MDF by a wrapping machine using a vinyl acetate-based adhesive to manufacture a decorative board. In addition, in order to evaluate the printability of the waterproof coated paper for decorative boards, gravure printing was performed using a nitrified cotton ink.

The test methods and evaluation methods are as follows, and the results are shown in Table 1. (A) Freeness is based on JIS P 8121.
It was measured by a Canadian standard freeness tester. (B) The surface strength was measured by the wax method based on JIS P8129. (C) The smoothness was measured using a Beck's smoothness tester based on JIS P 8119. (D) The water vapor transmission rate was measured based on JIS Z 0208 under the condition B, that is, at a temperature of 40 ° C. and a relative humidity of 90%. (E) The waterproof property was evaluated by immersing in water after bonding with MDF and increasing the weight due to water content. ⊚: Excellent ∘: Good x: Inappropriate (f) The glossiness was measured by a glossiness meter based on JIS P 8142. (G) The printability was evaluated by performing gravure printing on building materials and enlarging the shape of halftone dots. After printing, a usual urethane top coat was applied. ⊚: Excellent ◯: Good Δ: Slightly difficult ×: Inappropriate (h) Regarding tape peeling strength, cellophane tape (registered trademark) was strongly adhered to the coated surface, and then peeled off to observe surface fiber peeling and paper peeling. ◎: Excellent ○: Good △: Slightly difficult ×: Not suitable (i) Cross-cut suitability: cross-cut the coated surface with a cutter, firmly attach cellophane tape (registered trademark), then peel it off and observe the peeling condition between the paper did. ⊚: Excellent ∘: Good Δ: Slightly difficult ×: Inappropriate (j) Appropriateness of the lapping machine was observed by observing the occurrence of cracks, cracks, and crevices in the uneven portion. ⊚: None ∘: Almost none ∘: Somewhat bad ×:
Inappropriate (k) For V-cut aptitude, cut into a predetermined size, fold and expand in a cross shape, then turn it over and fold and expand again in a cross shape, following the creases on the coated surface side. Was applied with Magic Ink (registered trademark), and the degree of ink penetration was observed from the back side. ⊚: None ∘: Almost none ∘: Somewhat bad ×:
Inappropriate (l) Contamination resistance is the gloss change of the coated surface due to detergent, and
The glossiness of the coated surface due to alkali (NaOH) and acid (HCl) was evaluated. ◎: Excellent ○: Good △: Somewhat difficult ×: Not suitable

Example 2 L-BKP 100%, freeness 300 cc, polyacrylic amide type paper strengthening agent DRY 46 kg / T pulp liquid was used in a Fourdrinier paper machine at a speed of 20%.
Papermaking under conditions of 0 m / min, surface strength 18A, smoothness 38
A base paper having a basis weight of 30 g / m ² was obtained for 0 seconds. Soap-free emulsion polymerized SBR latex (trade name Pateracor SB-3
02, manufactured by Dainippon Ink and Chemicals, Inc. on one side of the base paper on an off machine using a vent blade coater.
The coating amount (dry weight) of g / m ² was applied, and then the coated surface was supercalendered at a speed of 500 m / min.
A waterproof coated paper for decorative sheet was obtained by treating under a condition of a nip pressure of 145 kg / cm and a roll temperature of 40 ° C. The obtained waterproof coated paper for decorative board was lapped on MDF by a wrapping machine using a vinyl acetate-based adhesive to manufacture a decorative board. In addition, in order to evaluate the printability of the waterproof coated paper for decorative boards, gravure printing was performed using a nitrified cotton ink. The same tests and evaluations as in Example 1 were performed, and the results as shown in Table 1 were obtained.

(Example 3) L-BKP 100%, a freeness of 350 cc, a pulp liquid of a polyacrylic amide type paper strengthening agent DRY 46 Kg / T was used at a fourdrinier paper machine at a papermaking speed of 20.
Papermaking under conditions of 0 m / min, surface strength 16A, smoothness 37
A base paper having a basis weight of 30 g / m ² was obtained for 0 seconds. Soap-free emulsion polymerized SBR latex (trade name Pateracor SB-3
02, manufactured by Dainippon Ink and Chemicals, Inc. on one side of the base paper on an off machine using a vent blade coater.
The coating amount (dry weight) of g / m ² was applied, and then the coated surface was supercalendered at a speed of 500 m / min.
A waterproof coated paper for decorative sheet was obtained by treating under a condition of a nip pressure of 145 kg / cm and a roll temperature of 40 ° C. The obtained waterproof coated paper for decorative board was lapped on MDF by a wrapping machine using a vinyl acetate-based adhesive to manufacture a decorative board. In addition, in order to evaluate the printability of the waterproof coated paper for decorative boards, gravure printing was performed using a nitrified cotton ink. The same tests and evaluations as in Example 1 were performed, and the results as shown in Table 1 were obtained.

(Example 4) L-BKP 80%, N-BK
P20%, freeness 200 cc, polyacrylic amide type paper strengthening agent DRY 46 kg / T pulp liquid was made with a Fourdrinier paper machine at a speed of 200 m / min, and surface strength was 2
A base paper with 3 A, a smoothness of 350 seconds and a tsubo of 30 g / m ² was obtained. Soap-free emulsion polymerization SBR latex (trade name: Pateracor SB-302, Dainippon Ink and Chemicals, Inc.)
Manufactured by a vent blade coater on an off-machine at a coating amount (dry weight) of 10 g / m ² , and then the coated surface is coated by a super calender.
The film was treated under the conditions of a speed of 500 m / min, a nip pressure of 145 kg / cm and a roll temperature of 40 ° C. to obtain a waterproof coated paper for decorative sheet. The obtained waterproof coated paper for decorative board was lapped on MDF by a wrapping machine using a vinyl acetate-based adhesive to manufacture a decorative board. In addition, in order to evaluate the printability of the waterproof coated paper for decorative boards, gravure printing was performed using a nitrified cotton ink. The same tests and evaluations as in Example 1 were performed, and the results as shown in Table 1 were obtained.

[0021]

[Table 1]

(Embodiment 5) P-liquid containing 100% L-BKP, 200 cc freeness, and polyacrylic amide type paper strengthening agent DRY 46 Kg / T was used at a fourdrinier paper machine to produce paper at a speed of 20.
Papermaking under conditions of 0 m / min, surface strength 23A, smoothness 41
A base paper having a basis weight of 30 g / m ² was obtained for 0 seconds. Soap-free emulsion polymerized NBR latex (trade name Pateracor LP26
2-4, manufactured by Dainippon Ink and Chemicals, Inc., on one side of the base paper with an off machine on a vent blade coater.
A coating amount (dry weight) of 0 g / m ² was applied, and then the coated surface was super-calendered at a speed of 500 m /
Min, a nip pressure of 145 kg / cm, and a roll temperature of 40 ° C. to obtain a waterproof coated paper for decorative sheet. The obtained waterproof coated paper for decorative board was lapped on MDF by a wrapping machine using a vinyl acetate-based adhesive to manufacture a decorative board. In addition, in order to evaluate the printability of the waterproof coated paper for decorative boards, gravure printing was performed using a nitrified cotton ink. The same tests and evaluations as in Example 1 were performed, and the results as shown in Table 2 were obtained.

Example 6 L-BKP 100%, freeness 200 cc, polyacrylic amide type paper strengthening agent DRY 46 kg / T pulp liquid was used in a Fourdrinier paper machine at a speed of 20%.
Papermaking under conditions of 0 m / min, surface strength 23A, smoothness 41
A base paper having a basis weight of 30 g / m ² was obtained for 0 seconds. Soap-free emulsion polymerized MBR latex (trade name Pateracol LP26
2-5, manufactured by Dainippon Ink and Chemicals, Inc. on one side of the base paper on an off machine by a vent blade coater 1
A coating amount (dry weight) of 0 g / m ² was applied, and then the coated surface was super-calendered at a speed of 500 m /
Min, a nip pressure of 145 kg / cm, and a roll temperature of 40 ° C. to obtain a waterproof coated paper for decorative sheet. The obtained waterproof coated paper for decorative board was lapped on MDF by a wrapping machine using a vinyl acetate-based adhesive to manufacture a decorative board. In addition, in order to evaluate the printability of the waterproof coated paper for decorative boards, gravure printing was performed using a nitrified cotton ink. The same tests and evaluations as in Example 1 were performed, and the results as shown in Table 2 were obtained.

(Comparative Example 1) A pulp liquid containing 100% L-BKP, 200 cc freeness, and a polyacrylic amide type paper strengthening agent DRY 46 Kg / T was used at a fourdrinier paper machine at a speed of 20%.
Papermaking under conditions of 0 m / min, surface strength 23A, smoothness 41
A base paper having a basis weight of 30 g / m ² was obtained for 0 seconds. Soap-free emulsion polymerized SBR latex (trade name Pateracor SB-3
02, manufactured by Dainippon Ink and Chemicals, Inc., 3 g on one side of the base paper with a vent blade coater on an off machine.
/ M ² coating amount (dry weight), and then the coated surface is treated with a super calender at a speed of 500 m / min, a nip pressure of 145 kg / cm, and a roll temperature of 40 ° C. I got a coated paper. The obtained waterproof coated paper for decorative board was lapped on MDF by a wrapping machine using a vinyl acetate-based adhesive to manufacture a decorative board. In addition, in order to evaluate the printability of the waterproof coated paper for decorative boards, gravure printing was performed using a nitrified cotton ink. The same tests and evaluations as in Example 1 were performed, and the results as shown in Table 2 were obtained.

(Comparative Example 2) A commercially available inter-paper reinforcing paper having a surface area of 30 g / m ² , a surface strength of 20 A and a smoothness of 200 seconds was MD-treated by a lapping machine using a vinyl acetate adhesive.
Lapping processing was applied to F to manufacture a decorative board. Incidentally, in order to evaluate the printability of the inter-paper reinforcing paper, gravure printing was performed using a nitrified cotton-based ink. The same tests and evaluations as in Example 1 were performed, and the results as shown in Table 2 were obtained.

(Comparative Example 3) A commercially available vinyl chloride film for decorative board was manufactured by lapping MDF with a vinyl acetate adhesive using a lapping machine. In order to evaluate the printability of the vinyl chloride film, gravure printing was performed using a vinyl acetate ink. The same tests and evaluations as in Example 1 were performed, and the results as shown in Table 2 were obtained.

[0027]

[Table 2]

FIG. 1 and Table 3 show an example of the relationship between the water vapor transmission rate and the coating amount of the clear waterproof resin. This shows the water vapor transmission rates of the same base paper and the same coating liquid as in Example 1 but different coating amounts, before and after applying the super calendar. The super calendar was carried out under the same conditions as in Example 1. For comparison, the results of coating SBR latex containing paraffin wax under the same conditions are also shown. If the coating amount of soap-free emulsion-polymerized SBR latex (trade name Pateracor SB-302, manufactured by Dainippon Ink and Chemicals, Inc.) is less than 5 g / m ² , the base paper surface cannot be covered uniformly and coating unevenness is not preferable. . On the other hand, if the coating amount exceeds 25 g / m ² , the drying property becomes poor and it becomes necessary to reduce the coating speed, which is not preferable in terms of production efficiency. In addition, the soap-free emulsion-polymerized SBR latex (trade name Pateracor SB-302, manufactured by Dainippon Ink and Chemicals, Inc.) coated with a super calender has a slightly higher moisture permeability than the one not coated. Although it falls, it is preferable to apply a super calendar to improve the gravure printing suitability and the like. Although only the SBR latex containing paraffin wax has a low water vapor transmission rate, it is necessary to apply a super calender in order to impart gravure printing aptitude, but when a super calender is applied, the water vapor transmission rate becomes high, which is not preferable. . It is considered that this is because the paraffin wax was transferred to the drum of the super calender, resulting in uneven coating film of the paraffin wax.

[0029]

[Table 3]

The relationship between the coating amount of the other clear waterproof resin and the moisture permeability is almost the same.

[0031]

Since the present invention is configured as described in detail above, it has the following effects. The surface strength defined by JIS P 8129 is 1
5 to 32 g of a dry weight of a clear waterproof resin containing no filler on at least one side of a base paper having a smoothness of 5 seconds to 32 A and a smoothness of 200 seconds or more specified by JIS P8119.
/ M ² coated waterproof paper for decorative boards is moisture-proof
It has excellent waterproofness, bending resistance, paper-to-paper strength, smoothness, printing gloss, and ink acceptance, and is suitable for manufacturing V-cut plywood and veneer by lapping machines. Without swelling or curling the material,
It is possible to provide a high-quality, high-quality product at a low price without generating mold, and thus it can be used as a substitute for a conventional film for decorative boards using vinyl chloride.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between water vapor transmission rate and a clear waterproof resin coating amount.

Claims (2)

[Claims] 1. A clear waterproof resin containing no filler on at least one side of a base paper having a surface strength of 15 to 32 A specified by JIS P 8129 and a smoothness of 200 seconds or more specified by JIS P 8119. A waterproof coated paper for a decorative sheet, characterized by being coated in a dry weight of 5 to 25 g / m ² . 2. The decorative board according to claim 1, wherein the clear waterproof resin is at least one of soap-free emulsion-polymerized SBR latex, soap-free emulsion-polymerized NBR latex, and soap-free emulsion-polymerized MBR latex. Waterproof coated paper for.