JP2003027392A - Thin paper for printed decorative sheet and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide thin paper which has a good surface property, good gravure printing suitability, in other words, gives fine and sharp printed images having excellent designs and further having proper and good resin impermeability, has excellent adhesive tape peelability and good profitability, and is used for printed plywood, and to provide a method for producing the same. SOLUTION: This thin paper for the printed decorative sheet is characterized by adding carboxymethylcellulose having a substitution degree of 0.3 to 0.6 in an amount of 0.05 to 3.0 wt.% based on the weight of the absolutely dry pulp. The method for producing the thin paper for printed decorative sheet is characterized by adding carboxymethylcellulose having a substitution degree of 0.3 to 0.6 and further adding at least one paper-strengthening agent in an amount of 0.1 to 6.0 wt. based on the weight of the absolutely dry pulp.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thin paper for a printed decorative board. More specifically, the present invention relates to a thin paper for a printed decorative board, which has good suitability for processing a printed decorative board and excellent suitability for gravure printing, and a method for producing the thin paper.

[0002]

2. Description of the Related Art A base paper for a printed decorative board is made of plywood, board or the like as a base material and also serves as a sealing material on the surface, and a solid or pattern is gravure printed and laminated on the base material. It is widely used in general building interiors and furniture as a printed plywood coated with polyurethane resin and dried.

The decorative boards include natural wood decorative plywood, melamine decorative board, diallyl phthalate (DAP) decorative board, polyester decorative board, vinyl chloride decorative board, and printed plywood,
The production of printed plywood is increasing year by year because it is easy to process and inexpensive. In addition, the base paper for printed decorative boards is expanding its application from sealing to thin-leaf pattern paper to special plywood other than printed plywood.

[0004] In the world, housing materials and furniture materials are dominated by laminated boards and printed sheets, which are slicing wood, and printed substrates are vulnerable to PVC, which produces harmful chlorine gas when burned. In recent years, olefin films and paper have come to be used.In recent years, the demand for quality of base paper has further increased, and paper with excellent inter-paper strength, surface abrasion resistance, and designability in gravure printing has been developed. Is required.

The properties required for the base paper for a printed decorative board include the following items. (1) There is little white spot in gravure printing. Good ink replenishment and good design reproducibility. (2) Strong paper interlaminar strength and surface strength. (3) Permeation of the resin during manufacture of the decorative board is reasonably good. (4) It is difficult to discolor (5) It has good shielding properties. (6) Good dimensional stability

[0006] Among these, particularly in regard to gravure printing suitability, in recent years, a "non-oak tone" with a light and delicate pattern has come to be preferred from an "oak tone" in which a traditional clear wood grain pattern is drawn. Therefore, the most important issue is whether or not the ink is properly applied to the light-colored portion called “highlight portion”. In addition, there is a problem that a fine luster shine called avatar is more noticeable as a pattern.

The second necessary characteristic is that the printed decorative board may use adhesive tape during construction or stick the adhesive tape at home for a long time, and when these tapes are peeled off, it tears between the paper layers. In order to lose the commercial value, it is desired that the surface strength of the base paper is high.

Further, dimensional stability is required to improve workability. It is necessary to suppress the dimensional change during the pulp fiber and fiber network processing step in order to prevent the dimensional change and the shape change such as warpage and twist in the processing step as much as possible.

Various techniques have been proposed to meet the above quality requirements. A base paper in which a resin is internally added to the base paper is known for the purpose of increasing the peel strength between the base paper. Further, a base paper obtained by impregnating a paper after papermaking with a resin has also been proposed (JP-A-61-83399, 63-19009).
No. 2, 63-190094). The internally added resin includes water-soluble polymer, synthetic rubber latex, synthetic resin emulsion, etc., and the impregnated resin includes urethane resin,
Amino alkyd resin, acrylic resin, etc. However, when the resin is impregnated, the interlayer strength of the paper is increased, but the surface roughness becomes rough and the gravure printing suitability deteriorates. Also,
By impregnating with the resin, the penetration of the surface coating resin after printing may be deteriorated and the peelability of the finished plywood with the adhesive tape may be deteriorated. In addition, economic efficiency deteriorates due to the increased number of steps.

On the other hand, in order to improve the suitability for gravure printing, an attempt has been proposed to further coat the base paper with a paint. (JP-A-4-314538, 7-42092
No. 7-42095, 7-42096, 7-420
No. 97), and as an attempt to improve both the paper interlaminar strength and the gravure printing suitability, it has been proposed to further coat the resin-impregnated base paper with a paint. (JP-A-1
However, by coating with a paint, the gravure printing suitability is improved, but the penetration of the resin for surface coating after printing is deteriorated, and the adhesive tape peeling property of the finished plywood is deteriorated. . Further, as in the case where the base paper after papermaking is impregnated with resin, the number of steps is increased, so that the economical efficiency is deteriorated.

[0011]

DISCLOSURE OF THE INVENTION The present invention has a good surface property and good aptitude for gravure printing. In other words, the image after printing is fine, sharp, and excellent in design. Is reasonably good and has excellent processing enemies,
It is an object of the present invention to provide a thin paper for printed plywood, which is excellent in adhesive tape peelability as a decorative board and has good economical efficiency.

[0012]

The present invention covers the following respective inventions. (1) A thin paper for a printed decorative board, which is used as a surface material for building materials or furniture, wherein the thin paper for a printed decorative board has a degree of substitution of 0.3 to 0.6 of carboxymethylcellulose in an absolute dry pulp weight. On the other hand, a thin paper for a printed decorative board, which is added in an amount of 0.05 to 3.0% by weight.

(2) JIS of the thin paper for the printed decorative board
The breaking length measured according to P 8113 is 5.5 to 1
The thin paper for a printed decorative board according to (1), which has a thickness of 1.0 km.

(3) Parker print surf (hereinafter referred to as PPS) on the gravure-printed surface of the thin paper for printed decorative board has a smoothness of 2-3 μm at a clamping pressure of 490 kpa and a clamping pressure of 1960 kpa.
Smoothness is 1.5 to 2.5 μm, and PPS compressibility (490 kpa PPS / 1960 kpa PPS) is 1.1 to 1.3 (1) to (2).
The thin paper for printed decorative boards according to.

(4) As a raw material, wood has a fiber cross-sectional area of 2
The thin paper for printed decorative board according to any one of (1) to (3), characterized in that it contains 10% by weight or more of pulp fibers having a size of 00 μm ² or less.

(5) After adding carboxymethyl cellulose having a degree of substitution of 0.3 to 0.6, at least one or more paper strengthening agents are added in an amount of 0.1 to 0.1% by weight of the absolutely dry pulp.
A method for producing a thin paper for a printed decorative board, which comprises adding 6.0% by weight.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Wood raw materials for the pulp used in the present invention include domestic oak, linden, edible maple, hemili, wig, domestic elm, birch etc., beach,
Hardwoods such as oak, alder, mangrove, eucalyptus and acacia, as well as conifers such as red pine, cedar, rice pine and spools can be used.

Above all, wood having a fiber cross-sectional area of 200 μm ² or less is preferable. The cross-sectional area of 200 μm ² or less means that the fibers are thin, and the pulp made from the fibers having fine fibers has a thin pulp, and the total number of pulps used when compared with the same basis weight is large. As a result, the number of fiber-to-fiber bond points increases, so the load applied to each fiber becomes easier to propagate, and the load is dispersed and applied to more fibers and fiber-to-fiber bond points than the above-mentioned load, resulting in dynamic elasticity. I think that the rate will improve.

Eucalyptus exserta, Eucalyptus delegatensis, Eucalyptus citrodora, Eucalyptus leizhou NO.1 are tree species having a fiber cross-sectional area of 200 μm ² or less. ,
Acacia mearnsii etc. can be mentioned.

Pulp fibers made of wood having a fiber cross-sectional area of 200 μm ² or less are used in combination with those having a fiber cross-sectional area of more than 200 μm ² as long as they are contained in an amount of 10% by weight or more per absolutely dry pulp. Improves stability. 200 μm
^The more pulp made from ² or less wood, the better the dimensional stability.

This is a method for measuring the fiber cross-sectional area of wood. However, when the wood chips are in a dry state, it is difficult to cut out the cross-section without destroying the fiber morphology and breaking the wood chips into water. After putting it in and gradually heating it to make it soft, the cusp of the tip is cut at right angles to the fiber direction using a razor. Next, since the cells are swelled in the water-containing state and are not suitable for observation, the cells are left to stand in ethanol for dehydration. The fiber cross-sectional area of the wood mouth surface is taken by taking a photograph of the fiber cross-sectional area of 1000 times using a scanning electron microscope, a laser microscope, etc., and measuring the fiber widths in the major axis direction and the minor axis direction of 200 or more fibers, and the value. From the above, the cross-sectional area of pulp fiber is calculated assuming that the fiber is rectangular. Since the cross-sectional area of each fiber in the wood chips is not constant, the average value is evaluated for 200 or more fibers.

The pulp is produced by cooking by a known method,
Bleaching is carried out by a known method. Considering the environment, it is preferable to bleach with ECF or TCF which does not use molecular chlorine element. As the pulp, hardwood bleached kraft pulp (L
-BKP) is preferable, and the blending amount is 60 to 100% by weight, preferably 80 to 100% by weight in consideration of unevenness of formation at the time of printing and resin permeability. If the bleached softwood kraft pulp (N-BKP) is blended in an amount exceeding 20% by weight, the texture will be deteriorated. Depending on the case, other synthetic fibers, non-wood fibers, etc. may be blended.

Freeness is 100 to 400 m
By adjusting the lCSF, preferably 200 to 300 ml CSF, the air permeability is increased, and it is effective for the proper penetration of the ink during gravure printing and the resin impregnated after printing.

In the present invention, 0.05 to 3.0% of carboxymethyl cellulose having a substitution degree (ether degree) of 0.3 to 0.6 (hereinafter abbreviated as CMC) is added to the beaten raw material.
The zeta potential of the pulp fiber is in the range of 0 to -25 mV although it varies depending on the type of pulp fiber. It is known that lowering the zeta potential improves the effect of papermaking chemicals added later, but as a means for lowering the zeta potential of pulp fibers, a polyelectrolyte having a negative charge is adsorbed to the pulp. There is a way. When the CMC in the present invention is added to the pulp fiber slurry, the CMC is adsorbed on the pulp, and the zeta potential of the pulp fiber changes greatly to the negative side.

When the substitution degree of CMC is less than 0.3, it is not suitable because it is insoluble in water and is not adsorbed on the pulp fiber surface and does not improve the effect of the paper strengthening agent. On the other hand, when the degree of substitution exceeds 0.6 and there are many ionic groups in the molecule, there is strong electrostatic repulsion with negatively charged pulp fibers, and affinity with pulp fibers. Since it becomes poor, even if the electrolyte coexists and the electrostatic repulsion is shielded to some extent, it does not stay evenly on the pulp surface and a sufficient paper strength increasing effect is not obtained, and the sheet strength (tear length) is sufficient. Not suitable because it runs out.

The addition ratio of CMC is preferably 0.05 to 3.0% by weight based on the weight of absolutely dry pulp. If the addition rate is less than 0.05% by weight, it is difficult to greatly change the zeta potential of the pulp fiber to the negative side, so the paper strength increasing effect becomes small and the breaking length becomes insufficient, which is not suitable. . On the other hand, if it exceeds 3.0% by weight, the viscosity when CMC is dissolved becomes too high and the workability is deteriorated, and the formation of the paper and the drainage may be deteriorated. is there. Also, it is not suitable because it leads to cost increase.

In the present invention, after adding CMC to the pulp fiber slurry, at least one or more paper strengthening agents are added in an amount of 0.1 to 0.6% by weight based on the weight of the absolutely dry pulp.
When CMC is added to the pulp fiber slurry, CMC is adsorbed on the surface of the pulp fiber and the zeta potential of the pulp fiber is greatly changed to the negative side. Generally, the zeta potential is the electrokinetic potential of fine particles, and when there are charged particles on the surface, it is established by the equilibrium between the ion layer, which is relatively strongly bound to the particle surface, electrostatic force, and random thermal motion. There is an electric double layer with the outer layer, and when the particles move, the inner layer of the ionic layer surrounding them also becomes integral, and shows the surface charge of the moving body moving in the medium. Generally, the zeta potential of pulp fibers is in the range of 0 to -25 mV. In the present invention, the addition of CMC to the pulp fiber slurry lowers the zeta potential of the pulp fibers, but the width thereof is lowered by 3 mV or more.

When CMC is not added, the paper strengthening agent is adsorbed only at the adsorption points existing on the pulp fiber surface. However, by adding CMC, not only the adsorption points of the pulp fibers but also the CMC uniformly adsorbed on the pulp are adsorbed. Therefore, since the paper strengthening agent is uniformly adsorbed with a high probability, the strength unevenness due to the paper strength enhancing agent is eliminated, and high paper strength is obtained. It becomes possible to obtain high paper strength by adding 0.6% by weight of paper strength enhancer. If the paper strength enhancer is less than 0.1% by weight, it has no effect.
Even if added in excess of 0.6% by weight, it will not be adsorbed on the pulp due to saturation of adsorption point and stain the papermaking system, or even if adsorbed, it will cause problems such as deterioration of formation and deterioration of drainage. Not preferable.

The paper-strengthening agent used in the present invention is a so-called paper-making paper-strengthening agent or wet paper-strengthening agent, and examples thereof include oxidized starch, amphoteric starch, cationized starch, acetylated starch,
Starch such as phosphate esterified starch, cationized guar gum, guar gum such as carboxymethylated guar gum,
Polyamide / epichlorohydrin resin, melamine resin,
Examples include polyethyleneimine resin, polyacrylamide resin, polyamide resin, etc.
Add after C addition. If desired, a sizing agent and a fixing agent may be added, and the same effect can be expected.

Examples of the filler include titanium dioxide, clay, talc, calcium carbonate and the like, and titanium dioxide is preferable for the hiding property of the sheet. The hiding property of the sheet greatly affects the appearance as a printed decorative board. Since the hiding property varies depending on the hue and basis weight of the sheet, it can be blended in the range of 0 to 25% by weight.

The paper machine of the present invention can be selected from known wet paper machines, such as a Fourdrinier paper machine, a gap former paper machine, a cylinder paper machine, and a short-net paper machine. . The formed paper layer is conveyed by a felt and dried by a Yankee dryer. It is generally known that a sheet dried with a Yankee dryer has high glossiness and high smoothness. The Yankee dryer is provided with a supply air that does not condense the evaporated water and a Yankee dryer hood for exhausting the supply air together with the evaporated water. Has been done.

In the present invention, the temperature of the Yankee dryer hot air is in the range of 150 to 400 ° C., preferably 150 to 300.
Within the range of ℃. If the temperature of the hot air is less than 150 ° C, it becomes difficult to uniformly and quickly evaporate the water vapor generated between the surface of the Yankee dryer and the sheet, and it is possible to prevent avatars that occur at the non-contact portion of the Yankee dryer and the sheet. Not suitable because it does not exist.

On the other hand, when the temperature of the hot air becomes higher than 400 ° C., it becomes over-dried and the strength of the pulp is lowered, so that not only the sheet strength is lowered but also the smoothness of the surface is deteriorated and wrinkles are generated during the sheet production. It is easy for paper to run out,
It is not suitable because it makes sheet manufacturing difficult.

In order to prevent condensation of water vapor generated in the Yankee dryer hood, improve thermal efficiency, and prevent avatars, a step of blowing hot air and sucking hot air containing steam is performed at least once. Usually, an appropriate amount of water is required for the sheet to stick to the Yankee dryer, and the range is preferably 45 to 65%. 45 water
If it is less than%, it is not suitable because it will not stick to the Yankee dryer. Conversely, if the water content exceeds 65%, a large amount of water vapor will be generated between the Yankee dryer and the sheet, and the sheet will float, making it suitable. Absent.

Even if the sheet has an appropriate amount of water that sticks to the Yankee dryer, the water vapor existing between the sheet and the Yankee dryer evaporates unevenly during the drying process,
As a result, avatars (minus gloss loss) occur,
In order to obtain gloss, it is necessary to uniformly and quickly remove water from the sheet attached to the Yankee dryer. For that purpose, it is indispensable to perform the step of sucking hot air containing steam at least once.

The sheet thus obtained is subjected to a surface treatment with a calendar to make the thickness profile uniform and to impart further gravure printing suitability. The calender is not particularly specified, and any calender such as a super calender or a soft calender that enhances the surface smoothness may be used, but off-machine is not economically disadvantageous.

In the present invention, the surface to be gravure printed, in the present invention, the glossy surface of Japan Tappi NO. 5 Oken type smoothness of 200 seconds or more, air permeability of 25 to 70 seconds and gloss of 20 to 50%
To In addition, it is important to set the air permeability to 25 to 70 seconds, more preferably 30 to 55 seconds. If the air permeability is less than 25 seconds, there are few short fibers, so that the interfiber bonding is small and the strength of the sheet is insufficient. Is not preferable. When the amount of short fibers is small, the denseness of the glossy surface of the sheet is inferior, and as a result, it is difficult to obtain a smoothness of 200 seconds or more and a glossiness of 20% or more, which is not preferable.

On the contrary, when the air permeability exceeds 70 seconds,
It is not suitable because it causes poor drying during sheet drying, resulting in unevenness in smoothness and unevenness in glossiness, and as a result, it becomes difficult to bring the smoothness and glossiness within the claimed range. When the smoothness is less than 200 seconds or the gloss is less than 20%,
Ink adhesion is poor in gravure printing, resulting in many miss dots. On the other hand, when the glossiness is 50% or more, the ink receptivity in gravure printing is good, but poor texture due to excessive moisture before drying, chemical addition, etc., and a slight gloss failure occur, making it unsuitable for appearance. Absent.

The most suitable for evaluating the gravure printing suitability is the PPS smoothness measuring opportunity. The PPS smoothness measuring machine has a thin width of 51 μm at the pressurizing portion (measuring land) of the measuring head. 490 kPa (5 kgf / cm
² ), 980 kPa (10 kgf / cm ² ), 1960 k
It can be performed under a clamp pressure close to printing conditions such as Pa (20 kgf / cm ² ). In addition, since the land width of 51 μm is about the same size as the halftone dots of printing, it is possible to measure fine irregularities, and ink receptivity and dot reproducibility (white spots) are important for gravure printing suitability. This is the most suitable smoothness measuring device for evaluation of.

The smoothness at a clamping pressure of 490 kpa exceeds 3 μm and is larger than the clamping pressure of 1960.
If the smoothness at kpa exceeds 2.5 μm and is larger, the ink receptivity in gravure printing is poor, resulting in many misdots. Also, the smoothness at a clamping pressure of 490 kpa is less than 2 μm, or the clamping pressure is 1960 kpa.
If the smoothness is less than 1.5 μm, the ink receptivity in gravure printing is good, but the nip pressure of the calender must be increased, resulting in an increase in density and deterioration of the hiding power.

In addition, PPS compressibility (PP of 490 kpa
If the SPS value of S / 1960 kpa is less than 1.1, the paper will have no cushioning property and will have many miss dots (white spots) in gravure printing. Further, the concealing property of the paper also deteriorates.
On the other hand, if the compressibility is greater than 1.3, it has cushioning properties, but inevitably the paper has a low density, and the surface becomes rough and the ink receptivity is poor.

JIS of the resulting thin paper for printed decorative boards
The fracture length in the fracture MD direction measured according to P 8113 is preferably 5.5 to 11.0 km. If the breaking length in the MD direction is less than 5.5 km, the strength (tensile strength, surface strength,
It is not suitable because the interlayer peel strength) cannot be imparted. On the other hand, if it is made larger than 11.0 km, it is necessary to advance the beating of the pulp or increase the addition of the paper strengthening agent.
It is not suitable because not only the texture of the paper is deteriorated but also the drainage is lowered and the pulp is apt to adhere to the inside of the papermaking machine system to make stable papermaking impossible.

The basis weight and thickness of the obtained thin paper for printed decorative board can be appropriately selected according to the required quality, but it is important that the density is in the range of 0.65 to 0.81 g / cc. Preferably in the range of 0.70 to 0.79 g / cc,
More preferably, it is in the range of 0.73 to 0.77 g / cc. If the density is less than 0.65 g / cc, it has cushioning properties, but the surface is rough and not only the ink inking property deteriorates, but also ink strike-through easily occurs and the gravure printing suitability deteriorates, which is not suitable. . Conversely, 0.81
If it exceeds g / cc, the smoothness is improved, but the resulting thin paper for printed decorative boards becomes too stiff and is apt to crack during processing, which is not suitable.

[0044]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples and comparative examples,% means% by weight.
In addition, the measurement and evaluation of the characteristics were performed by the following methods. (1) Thickness Measured according to JIS P-8118. (2) Breaking length Measured according to JIS P-8113. (3) Oken type smoothness and air permeability The Oken type smoothness and air permeability were measured according to J.TAPPI No.5.

(4) PPS smoothness Using a PPS-78 type Parker print surf paper smoothness tester manufactured by Messmer, a clamping pressure of 490 k was used.
The smoothness (surface roughness) at Pa and 1960 kPa was measured. The measured value is expressed in μm.

(5) Dimensional stability Marks are marked on thin paper for printed decorative boards with a span of about 250 mm, and humidity is adjusted for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 50%. Accuracy Measured with a two-dimensional coordinate measurement device (digital reader, DR-550-D, manufactured by Dainippon Screen Co., Ltd.). Then, 120 degrees, 15
After heating for 2 minutes, again under the environment of 23 degrees and 50% relative humidity, 2
After humidity control for 4 hours, the same gauge length L1 mm is measured.
From these, the dimensional change rate α is calculated by Equation 1. When the thin paper for a printed decorative board is produced by an ordinary paper machine and has anisotropy, the dimensional change rate is indicated by the longitudinal direction, the transverse direction, and the geometric mean value in the longitudinal direction and the transverse direction. The smaller the dimensional change rate, the higher the dimensional stability of the thin paper for printed decorative boards. In the present invention, if the dimensional change rate is 0.025% or less, it is determined to be acceptable. Formula 1 α (%) = “(L0−L1) / L0” × 100

(6) Suitability for gravure printing 1) Test method Testing machine STM printing station type gravure testing machine Ink Gravure ink for Toyo Ink Publishing Viscosity: 10 seconds with Zahn cup No3 (solvent: xylene) Speed 40m / min Printing pressure 200N / 5cm Edition Conventional gravure, halftone gravure

2) Ink inking evaluation method The ink inking state was observed by enlarging with a digital scope. Observation point Conventional version: Plate depth 5 μm, 10
μm Halftone dot gravure plate: 15% Halftone dot: Very good: Good: Somewhat poor ×: Inferior

3) Avatar The obtained thin paper for printed decorative board was visually evaluated for printing unevenness due to avatar after gravure printing. The evaluation was carried out in the following 5 grades, and 4 or more were passed. 5: No printing unevenness 4: Almost no printing unevenness 3: There is printing unevenness but it is hardly noticeable 2: Printing unevenness is noticeable 1: Conspicuous printing unevenness

(7) Cellophane tape peeling test Prepare a sample cut into A4 size, and stick three cellophane tapes (Cellophane adhesive tape: TK-18, manufactured by Uni Kogyo Co., Ltd.) so that they are parallel to the paper flow. .
After rotating the hand-made couch roll (13 kg) once on it, peel off the cellophane tape at a speed of 3 cm / sec and visually observe the state of the sheet surface, with the average value of n = 3 as the representative value, Judgment was made based on the 5 grade standard and 4 or more was passed. 5: No fiber dropouts at all 4: Almost no fiber dropouts 3: Fiber dropouts are barely noticeable 2: Fiber dropouts are conspicuous 1: Fiber dropouts are very high

(8) Formation determination The formation of the thin paper for printed decorative board thus obtained was determined according to the following five-stage standard, and a total score of 20 persons was set as a representative value and 80 points or more were accepted. 5: There is no thickness unevenness, and the texture is very good. 4: There is no thickness unevenness, and the texture is good. 3: Thickness unevenness is small but hardly noticeable. 2: Thickness unevenness is noticeable. 1: Thickness unevenness is noticeable. Very many

[0052] Example 1 fiber cross-sectional area and beating a 100% hardwood bleached pulp (L-BKP) prepared from eucalyptus Exar over data material 128 .mu.m ² to freeness 440MlCSF, degree of substitution 0.40 (solid content concentration of 1% CMC having a solution viscosity of 100 mPa · s and a Daiichi Kogyo Seiyakuhin prototype # 412C) was added in an amount of 0.1% based on the weight of the absolutely dry pulp. Thereafter, 0.4% of a sizing agent (SPE manufactured by Arakawa Chemical Industry Co., Ltd.) was added, and 1.5% of a synthetic band was added as a fixing agent. Further, as a paper strengthening agent, cationized starch (manufactured by Oji Constarch Co., Ltd.)
2.9% of Oji Ace K-100) and 2.9% of amphoteric PAM (KW831HC manufactured by Arakawa Chemical Industry Co., Ltd.) were added, and the temperature of hot air with a Yankee dryer was 160 ° C using a Harper type paper machine. After being blown from the anti-dryer side, hot moist air is sucked in to make thin paper having a basis weight of about 20 g / m ² , and the paper is soft calendered to have a basis weight of 32.1.
A g / m ² thin paper for a printed decorative board was obtained.

Example 2 CMC having a degree of substitution of 0.35 (solution viscosity of solid content 1% 100 mPa · s, manufactured in-house) was added at 2.9% and paper strength was increased. The agent is amphoteric PAM5.
Basis weight of 45.8 g as in Example 1 except for 8%.
A thin paper for printed decorative boards of / m ² was obtained.

Example 3 CMC having a substitution degree of 0.55 (solution viscosity of solid content 1% 1600 mPa · s, serogen 4H manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was added at 0.06% and cation. Addition rate of modified starch is 0.6%, addition rate of amphoteric PAM is 0.6%
23.4 g / in the same manner as in Example 1 except that the percentage was changed to%.
An m ² thin paper for a printed decorative board was obtained.

Example 4 CMC having a degree of substitution of 0.45 (solution viscosity 900 mPa · s with a solid content of 1%, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., 450)
60.0 g of basis weight in the same manner as in Example 3 except that the addition rate of A) was 0.3%, the addition rate of cationized starch was 3.0%, and the addition rate of amphoteric PAM was 1.0%. A thin paper for printed decorative boards of / m ² was obtained.

Comparative Example 1 A thin paper for printed decorative board having a basis weight of 23.4 g / m ² was obtained in the same manner as in Example 3 except that CMC was not added.

Comparative Example 2 CMC having a degree of substitution of 0.7 (solution viscosity of 1% solid content 1700 mPa · s, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., serogen BSH4) was added at 0.2%. Example 4 except
Similarly to, a thin paper for a printed decorative board having a basis weight of 60.0 g / m ² was obtained.

Comparative Example 3 CMC having a substitution degree of 0.45 (solution viscosity 900 mPa · s with a solid content of 1% is 900 mPas manufactured by Daiichi Kogyo Seiyaku Co., Ltd. 450 A)
A thin paper for printed decorative board having a basis weight of 32.1 g / m ² was obtained in the same manner as in Example 1 except that the addition rate of was set to 0.04%.

Comparative Example 4 L-BKP 100% produced from eucalyptus grandis material having a fiber cross-sectional area of 254 μm ² was used, and CMC substitution degree was 0.45 (solution viscosity 900 at 1% solid content concentration).
Basis weight 3 in the same manner as in Example 1 except that the addition rate of mPa · s Daiichi Kogyo Seiyaku Pharmaceutical 450A) was 3.3%.
2.1 g / m ² of thin paper for printed decorative board was obtained. The physical properties of the resulting thin paper for printed decorative board were measured and are shown in Table 1.

[0060]

[Table 1]

As is clear from the results in Table 1, Example 1
The thin papers for printed decorative boards of Nos. 4 to 4 are excellent in gravure printing suitability and have sufficient strength when used as a surface material for building materials or furniture. On the other hand, when CMC is not added (Comparative Example 1), the substitution degree of CMC is out of the specified range (Comparative Example 2), or when the CMC addition rate is out of the specified range and becomes small (Comparative Example 3). ), The breaking length becomes insufficient, and at the same time, the cellophane tape peeling test that images the practical use of thin paper for printed decorative boards becomes insufficient. Also, if the CMC addition rate exceeds the specified range and becomes large,
(Comparative Example 4), PPS smoothness is lowered due to deterioration of texture, and gravure printing suitability is poor.

[0062]

EFFECT OF THE INVENTION By adding a specific CMC in a certain range and adding a paper strengthening agent in a specific range, it can be used as a surface material for building materials or furniture having good gravure printing suitability and strength. It has become possible to obtain thin paper for printed decorative boards.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinya Yamamoto             1 Ojimachi, Ebetsu City, Hokkaido Oji Paper Co., Ltd.             Company Ebetsu factory (72) Inventor Seiichi Ide             1 Ojimachi, Ebetsu City, Hokkaido Oji Paper Co., Ltd.             Company Ebetsu factory F-term (reference) 4L055 AA03 AC06 AG46 AG48 AG72                       AH16 BB03 BE20 CF03 EA29                       EA32 FA15 FA30 GA22 GA28

Claims (5)

[Claims] 1. A thin paper for a printed decorative board, which is used as a surface material for a building material or furniture, wherein the thin paper for a decorative printed board has an absolute dryness of carboxymethyl cellulose having a substitution degree of 0.3 to 0.6. 0.05-3 with respect to weight.
A thin paper for a printed decorative board, which is characterized by containing 0% by weight. 2. A thin paper according to JIS P for the printed decorative board.
The breaking length measured according to 8113 is 5.5-11.0k
The thin paper for a printed decorative board according to claim 1, which is m. 3. A Parker print surf (hereinafter referred to as PPS) on the surface for the gravure printing of the thin paper for printed decorative boards.
The paper smoothness tester has a smoothness of 2-3 μm at a clamping pressure of 490 kpa and a smoothness of 1.5 to 2.5 μm at a clamping pressure of 1960 kpa, and has a PPS compressibility (49
0 kpa PPS / 1960 kpa PPS) is 1.1
It is -1.3, The thin paper for printed decorative boards of Claim 1 or Claim 2 characterized by the above-mentioned. 4. The raw material has a fiber cross-sectional area of wood of 200 μm.
The thin paper for a printed decorative board according to any one of claims 1 to 3, which contains 10% by weight or more of pulp fibers having a m ² or less. 5. After adding carboxymethylcellulose having a degree of substitution of 0.3 to 0.6, at least one or more kinds of paper strengthening agents are added to the dry pulp weight of 0.1 to 6.0.
A method for producing a thin paper for a printed decorative board, which is characterized by adding by weight%.