JP2011058112A - Decorative board stock paper, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide decorative board stock paper equipped with a sufficient concealing property although it is a thin material having 20-55 g/m<SP>2</SP>unit weight, also without generating spots by moisture absorption over time, and further having a good printing aptitude and pasting aptitude on a substrate material. <P>SOLUTION: This decorative board stock paper used for performing the printing on the decorative board stock paper and pasted on a substrate material to produce a decorative board is produced by a paper machine having a Yankee dryer, contains ≤1.0 wt.% sizing agent and 2.5-15 wt.% titanium oxide, and having 20-55 g/m<SP>2</SP>weight basis and 3.2-4.8 range paper surface pH. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a decorative board base paper and a method for producing a decorative board base paper.

  Conventionally, as a printed decorative board, a decorative board in which a plain paper or a pattern is gravure-printed and a resin-coated printing paper or thin paper is pasted on a base material such as plywood, MDF (medium fiber board), particle board, etc. However, it is widely used for interior construction materials and furniture.

The base paper used for the printed decorative board (hereinafter referred to as “decorative board base paper”) is adjusted to a basis weight of 23 to 60 g / m ² using cellulose fibers or the like as a raw material, and the base color unevenness of the base plate is adjusted. In order to conceal them, products containing titanium oxide, calcined clay, etc., and products containing colorants are widely used (see Patent Document 1).

  In addition, in printed decorative board base paper mixed with titanium oxide, in order to improve the yield of the filler, a method of chemically forming a primary aggregate using bentonite using a charge adjusting agent and a retention agent is known. (See Patent Document 2).

  The decorative board base paper is internally added with a paper strength enhancer such as starch or polyacrylamide in order to strengthen the bond between the fibers. However, when the paper strength enhancer is internally added, the peelability of the dryer is lowered, and the surface smoothness of the decorative board base paper is remarkably deteriorated. For this reason, usually, a dryer release agent such as a sizing agent is used together in the decorative board base paper to simultaneously ensure the surface strength and smoothness, which are the basic properties of the decorative board base paper.

JP 2002-138396 A JP 2008-231630 A

  When the decorative board base paper is continuously left in a hot and humid environment, a stain is likely to occur. Because the decorative base paper is printed on the non-bonded surface of the base material with a design such as a pattern or pattern, the occurrence of stains impairs the product value. There arises a problem that it is difficult to use the base paper.

  In addition, as a decorative board base paper having properties satisfying the adhesiveness to the base material and the suitability for gravure printing frequently used for pattern and pattern printing on the decorative board base paper, a drying treatment is performed with a Yankee dryer, Single glossy paper with a glossy surface on the printed side and a non-glossy side as the bonding surface is preferably used. By drying from one side with a Yankee dryer, the resin component in the decorative board base paper is transferred to the glossy surface. It becomes easy, and has the problem that the expression of the stain becomes more conspicuous as compared with the decorative sheet base paper using the long mesh multi-cylinder.

The present invention has been made in order to solve the above-mentioned problems, and although it is a thin material having a basis weight of 20 to 55 g / m ² , it has a sufficient concealing property and generation of a stain due to moisture absorption over time. Furthermore, it aims at providing the manufacturing method of decorative board base paper and the decorative board base paper with favorable printability and the bonding suitability to a base material.

In order to solve the above-mentioned problems, the decorative board base paper of the invention according to claim 1 is manufactured by a paper machine having a Yankee dryer, and in the decorative board base paper to be bonded to the substrate as the base paper in the decorative board, titanium oxide has It is contained at least, the content of titanium oxide is 2.5 to 15% by weight, the content of the sizing agent is 1.0% by weight or less per dry pulp, and the basis weight is 20 to 55 g / m ^2. The paper surface pH is 3.2 to 4.8.

  The decorative board base paper of the invention according to claim 2 is characterized in that, in addition to the constitution of the invention of claim 1, the sizing agent is a rosin emulsion sizing agent.

  In addition to the constitution of the invention according to claim 1 or 2, the decorative board base paper of the invention according to claim 3 contains a charge adjusting agent in the decorative board base paper, and the charge adjusting agent is a sulfone. The main component is an acid compound.

  In addition to the configuration of the invention according to any one of claims 1 to 3, the decorative board base paper of the invention according to claim 4 contains a yield improver in the decorative board base paper, and the yield The improver is characterized by comprising a polyacrylate ester as a main component.

  The decorative board base paper of the invention according to claim 5 is characterized in that, in addition to the constitution of the invention according to any one of claims 1 to 4, the crystal structure of the titanium oxide is anatase type.

  Moreover, the manufacturing method of the decorative board base paper of the invention which concerns on Claim 6 is a manufacturing method of the decorative board base paper bonded together to a base material as a decorative board base paper in a decorative board, Comprising: Content is 2.5 to 15 weight% Producing the decorative board base paper by supplying a pulp material containing at least a titanium oxide and a sizing agent having a content of 1.0% by weight or less per dry dry pulp to a paper machine having a Yankee dryer. It is characterized by.

The decorative board base paper of the present invention is a thin material having a basis weight of 20 to 55 g / m ² , has sufficient concealing property, and does not generate a stain due to moisture absorption over time. The bonding suitability of is good.

  Although the cause of stains on the decorative board base paper is not clear, when moisture or the like from the atmosphere or base material is absorbed or moved into the decorative board base paper, it is contained in the decorative board base paper, for example, an unfixed sizing agent. It is assumed that it is generated by agglomeration or oxidation of resin components such as, especially when a large amount of titanium oxide is contained in the decorative board base paper, because the titanium oxide itself has hydrophobicity, the vicinity of titanium oxide due to moisture absorption It is presumed that the migration of resin components such as sizing agent is likely to occur and the occurrence of stains becomes significant.

  Specifically, the decorative board base paper can be used as follows. A desired pattern or pattern is printed on the decorative base paper by gravure printing or the like. Thereafter, a top coat resin layer is applied to the surface of the decorative board base paper to produce decorative paper. This decorative paper is bonded to the substrate with an adhesive or an adhesive tape. A decorative board is manufactured by this.

  The decorative board base paper is preferably produced by a paper machine having a Yankee dryer (hereinafter referred to as “Yankee machine”). Paper produced by a paper machine having a Yankee dryer has high smoothness on one side (glossy surface) corresponding to the Yankee dryer contact surface, so that the gravure printing suitability is improved. The decorative board base paper is made of paper pulp containing a raw material pulp containing titanium oxide and a sizing agent, and more preferably containing a sulfuric acid band, a charge adjusting agent, and a yield improving agent.

  Pulp types that can be used for decorative board base paper include hardwood pulp (especially hardwood kraft pulp), softwood pulp (especially softwood kraft pulp), waste paper pulp, etc. Included waste products are also included. In general, hardwood pulp is short and thin, while conifer pulp is long and thick. Therefore, high hardwood pulp content has high air permeability, and low hardwood pulp content has low air permeability. I can say. Moreover, since softwood pulp disturbs formation, it is preferable that a compounding rate shall be 20 weight% or less with respect to the raw material pulp whole quantity.

  The beating degree of the raw material pulp is preferably adjusted to a range of 100 to 400 mL in terms of Canadian standard freeness (freeness). DDR (double disc refiner) can be used for beating. More preferably, it is 150-400 mL. When it is less than 100 mL, beating progresses, the ratio of pulp having a short fiber length increases, and the problem of high air permeability tends to occur. When the air permeability becomes high, it becomes difficult for the moisture in the decorative board base paper to evaporate smoothly during the drying process with the Yankee dryer that can be suitably used in the present invention, and the decorative board base paper sticks to the Yankee dryer. Is weak, and the smoothness of the Yankee dryer contact surface (glossy surface) is lowered, which is not preferable. If it exceeds 400 mL, the ratio of the pulp having a long fiber length increases, and the smoothness decreases. When the smoothness is lowered, the gravure printing aptitude is deteriorated.

  As titanium oxide, it is preferable to use a titanium oxide having a particle size of 0.1 μm to 2.5 μm. The structure of titanium oxide includes anatase and rutile types, but the anatase type has a lighter specific gravity of 3.9 (rutile 4.2) than the rutile type, so it tends not to fall off on the wire and tends to improve yield. Furthermore, the anatase type has an effect that the specific surface area is high and the adsorptivity is high compared to the rutile type, so that even if a small amount of the sizing agent is present on the surface, the sizing agent does not easily move during moisture absorption, and stains are unlikely to occur. Therefore, it is preferable to use the anatase type.

  As fillers other than titanium oxide, known ones such as talc, clay and calcium carbonate can be blended, but titanium oxide is preferable in order to improve the concealability.

  The content of titanium oxide is preferably adjusted in the range of 2.5 to 15% by weight per raw pulp absolute dry weight, and more preferably 5.0 to 12% by weight per raw pulp absolute dry weight. When the content of titanium oxide is less than 2.5% by weight based on the absolute dry weight of the raw material pulp, the concealability is insufficient, which is not preferable. Moreover, when it exceeds 15 weight% per raw pulp absolute dry weight, since the tangle of the pulp fibers in a decorative board base paper will be inhibited and the intensity | strength of paper itself will be reduced, it is unpreferable. Moreover, since the whole paper becomes hard, the gravure printing aptitude deteriorates.

  The content of the sizing agent is preferably 1.0% by weight or less per raw dry pulp weight, more preferably 0.3 to 0.8% by weight per raw pulp dry weight. If the sizing agent is contained excessively, there will be a sizing agent that does not bind directly to the pulp fibers, so the sizing agent will move easily due to moisture absorption from the air or from the base material, and stains will occur through aggregation and oxidation reactions. It becomes easy to do. By setting the content of the sizing agent to 1.0% by weight or less, it is possible to make it difficult for spots to occur.

  Although it is preferable to reduce the content of the sizing agent as much as possible, if the content of the sizing agent is less than 0.3% by weight based on the absolute dry weight of the raw material pulp, the peelability of the decorative board base paper from the Yankee dryer decreases, and the Yankee Raw material pulp fiber is taken into the dryer, the contact surface of the Yankee dryer becomes fuzzy, and there is a problem that the flatness is lowered, and fluffing causes the titanium oxide in the paper layer to fall off and the generation of paper powder due to the removal of the raw pulp fiber This tends to cause a problem that printability is deteriorated.

  As the sizing agent, an emulsion sizing agent is preferably used. Emulsion-based sizing agents are excellent in water dispersibility and have good fixation on pulp fibers, so that stains hardly occur. Emulsion sizing agents include rosin emulsion sizing agents and styrene-acrylic emulsion sizing agents. Among them, rosin emulsion sizing agents are particularly preferred. The rosin-based emulsion sizing agent is taken in between the cationic sulfate bands fixed on the pulp fibers and is firmly bonded, so that the sizing agent does not move due to moisture absorption, and stains are unlikely to occur. Furthermore, since it couple | bonds in the form which bridge | crosslinks between fibers, the strength between pulp fibers is easy to improve and it is more preferable as a decorative base paper which requires surface strength.

  In order to supplement the peelability from the Yankee dryer, it is preferable to use an externally added release agent in addition to the sizing agent (internally added sizing agent). There is a problem that the strength decreases when the internal release agent is used, but the external release agent does not have such a strength decrease. Further, since the release agent is present only on the glossy surface side that comes into contact with the Yankee dryer, it is more preferable because it does not hinder the penetration of the adhesive when the substrate is bonded.

  As the external additive release agent, it is particularly preferable to use a vegetable oil-based release agent. A vegetable oil-based release agent can obtain a release effect with a small content.

  The sulfuric acid band is preferably used because it improves the yield of additive chemicals such as titanium oxide and sizing agents. This is because titanium oxide is difficult to self-fix to the pulp fiber in the pulp slurry, and therefore it is necessary to efficiently allow the titanium oxide to yield on the paper. The sulfuric acid band can be suitably used as a fixing agent for a rosin sizing agent. The content of the sulfate band is preferably 1.6 to 3.5% by weight based on the dry weight of the raw material pulp. When the content is less than 1.6% by weight, additive chemicals such as titanium oxide and sizing agent are not sufficiently fixed to the pulp fiber, and problems such as a decrease in concealability and generation of spots may occur. If the content exceeds 3.5% by weight based on the absolute dry weight of the raw material pulp, excessive sulfuric acid bands may lead to excessive aggregation of not only the raw material pulp but also titanium oxide. There is a possibility that the flatness on the printing surface of the decorative board base paper is lowered, and the quality of the decorative board base paper is deteriorated.

  Patent Document 2 describes a technique for forming a primary aggregate of titanium oxide and bentonite in order to improve the yield of titanium oxide. Here, since iron is contained in bentonite, it reacts with the rosin sizing agent to form iron rosinate, which is presumed to cause stains.

  In order to improve the yield of titanium oxide, it is preferable to use a charge adjusting agent and a yield improving agent in combination. Pinhole of decorative base paper, which is presumed to be due to aggregation of titanium oxide by stabilizing the binding with pulp fibers by aggregating and cationizing titanium oxide using a charge control agent and further a yield improver. The number of defects in the shape is reduced, and it is possible to suppress a decrease in concealability and printability.

  According to the inventors' knowledge about the improvement of the yield of titanium oxide using the charge adjusting agent and the yield improving agent, an anionic charge adjusting agent is used, the ionicity of the surface of the titanium oxide is made anionic, and the cation An agglomerate made of titanium oxide is formed by the yield improver having the property. The agglomerates are agglomerated by a cationic yield improver, and thus exhibit a cationic property. The cationic agglomerates chemically bond to anionic pulp fibers. Thereby, the yield of titanium oxide can be improved.

  As the charge adjusting agent, an anionic one can be preferably used. For example, a sulfonic acid compound (preferably at least one of sodium styrenesulfonate, sodium allylsulfonate, sodium acrylamidesulfonate, sodium vinylsulfonate, etc. Sulfonic acid compounds obtained by polymerizing one kind as a monomer), sodium polyacrylate, colloidal silica, and the like. Among these, a sulfonic acid compound is preferable, and examples of the charge control agent having a sulfonic acid compound as a main component include a high holder D550 manufactured by Kurita Kogyo Co., Ltd., VERSA-TL502 manufactured by Nippon NSC Co., Ltd. -TL3 etc. are mentioned.

  When the charge adjusting agent is not contained, the surface of the titanium oxide cannot be sufficiently anionized, and the cationic yield improver does not act sufficiently, and the yield of titanium oxide on the decorative board base paper tends to decrease. When the yield decreases, the concealability is insufficient, the charge balance in the system tends to be close to the cation, and papermaking defects may increase.

  As the yield improver, a cationic one can be preferably used. For example, a cationic polyacrylic ester obtained by polymerizing an acrylic ester such as ethyl acrylate and butyl acrylate together with a cationizing agent as one component of a monomer. Cationic polyacrylamide, cationic polyethyleneimine, cationic starch and the like can be used. However, cationic polyacrylamide, cationic polyethyleneimine, cationic starch, etc. are too cationic to enlarge the aggregate of titanium oxide, or weakly cationic and inferior in aggregate formation ability with titanium oxide. As the retention improver, a cationic polyacrylate is preferable. Examples of the yield improver mainly composed of a cationic polyacrylic acid ester include a high holder 220 manufactured by Kurita Kogyo Co., Ltd., a high set C series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and pararoc 490K307 manufactured by Asada Chemical Co., Ltd. It is done.

  When the cationic polyacrylic acid ester is cured by crosslinking reaction when irradiated with an electron beam, the strength of the decorative base paper is further improved. As such a cationic polyacrylic acid ester, one having an unsaturated bond in the ester group is preferable.

  In addition, the cationic polyacrylic ester is chemically bonded so as to surround the periphery of titanium oxide anionized with the charge control agent, and also chemically bonded to the anionic pulp fiber. The generation of pinholes due to the aggregates is reduced, and there is an effect of enhancing the concealability, and the yield of the aggregated titanium oxide on the decorative board base paper is increased.

  Electron beam curable ink is often used for printing patterns and designs on decorative board base paper, and curing processing is performed with electron beams. The decorative board base paper containing titanium oxide is electron beam in the curing process after printing. When it is irradiated, it is difficult to be affected by the electron beam, so that the deterioration of the raw material pulp due to the electron beam irradiation is suppressed, and the paper strength of the decorative board base paper is prevented from being lowered.

  In the absence of a yield improver, titanium oxide cannot be sufficiently retained on the paper, so the concealability tends to be insufficient, and the yield of the sizing agent tends to decrease, and it does not bind sufficiently to the pulp fibers. Sizing tends to exist and stains are likely to occur.

  The content of the charge adjusting agent is such that the charge of the raw material containing pulp and other chemicals measured with a charge measuring device (Gmbh PCD-T3 manufactured by BTG Mutek) is −0 meq / g to −30 meq / g. Adjust it.

  The content of the yield improver and the charge control agent is such that the solid content content of the charge control agent is 1.0-30. It is preferably in the range of 0, more preferably in the range of 5.0 to 20.0 per raw pulp absolute dry weight. If the content of the charge control agent with respect to the content of the yield improver is less than 1.0 per raw pulp absolute dry weight, the surface of the titanium oxide cannot be made sufficiently anionic, and the titanium oxide and the yield It is difficult to efficiently make agglomerates of improvers. Further, when the content of the charge control agent with respect to the content of the yield improver exceeds 30 per raw pulp absolute dry weight, the anionic property of the surface of the pulp fiber becomes too strong and is contained in the slurry containing the pulp raw material. Agglomerates in which fats and oils are agglomerated are incorporated into paper as a defect, which tends to cause a problem of pitch.

  Titanium oxide, sizing agent, and more preferably, the sulfuric acid band, charge control agent, and yield improver are contained in the order containing titanium oxide and dispersed in a slurry containing pulp raw material. It is preferable to contain a paper strength agent, then a sulfuric acid band, followed by a sizing agent, a charge control agent, and finally a yield improver. By making the sulfuric acid band into the above content, it is preferable to adjust the paper surface pH of the decorative board base paper to a range of 3.2 to 4.8.

  The paper surface pH in the present invention is measured according to JAPAN TAPPI Paper Pulp Test Method No. In accordance with No. 49-2, measurement was performed on the side of the decorative board base paper that was printed, but when the pH was less than 3.2, it was necessary to contain an excess of sulfuric acid band, and the corrosion and chemical yield in the paper machine system were reduced. Problems are likely to occur. On the other hand, when the pH exceeds 4.8, the yield of the sizing agent and titanium oxide due to the sulfuric acid band is deteriorated, and further, the problem that the effect of the auxiliary chemicals such as the yield improver and the charge adjusting agent becomes difficult to occur easily occurs.

  In addition to the above, the decorative board base paper of the present invention can contain a paper strength enhancer and the like. Although it does not specifically limit as a paper strength enhancer, Amphoteric polyacrylamide, anionic polyacrylamide, etc. can be used conveniently. The content is preferably 0.3% to 5.0% by weight per raw pulp absolute dry weight, and more preferably 1.0 to 4.0% by weight per raw pulp absolute dry weight. If it is less than 0.3% by weight based on the absolute dry weight of the raw material pulp, the paper strength enhancer is insufficient, and the pulp fibers cannot be tied together, and the paper strength of the paper may not be sufficient. When the content exceeds 5.0% by weight based on the absolute dry weight of the raw material pulp, the releasability of the dryer is remarkably deteriorated, the surface smoothness is low and the gravure printing suitability is deteriorated, and yellowing occurs due to nitrogen contained in the acrylamide. Inherent.

The basis weight of the decorative board base paper is preferably ²⁰ to 55 g / m ² , more preferably 23 to 50 g / m ² . . When the basis weight is less than 20 g / m ² , the decorative board base paper is slightly inferior in tensile paper strength, tear paper strength, or concealability. If it exceeds 55 g / m ² , the paper's tensile paper strength, tearing paper strength, and concealment are sufficient, but the smoothness is low, so the gravure printability is not good.

The decorative board base paper preferably has a degree of bump size in 30 seconds described in JIS P8140 of 12 g / m ² or more. When it is lower than 12 g / m ² , the adhesive does not penetrate into the decorative board base paper, and the adhesive strength with the base material is weak, resulting in poor bonding.

  The decorative board base paper preferably has an opacity defined by JIS P 8138 of 55% or more, more preferably 60% or more, and still more preferably 70% or more. An opacity of less than 55% is not preferable because the covering property of the decorative board base paper is insufficient, and it is necessary to add a process such as printing for improving the covering property.

  Although the opacity is greatly improved by titanium oxide contained in the decorative board base paper, the opacity can be adjusted by using a conventionally known filler such as clay in combination with improving the gloss of the dry surface of the Yankee dryer. If the opacity is less than 55%, sufficient concealability cannot be ensured, and if the filler is contained excessively in order to improve the over-opacity, the paper strength as the decorative board base paper is lowered and the processing suitability is impaired. .

  Since printing on decorative paper base paper is mainly performed by the gravure printing method, the glossy surface to be printed is preferably smooth, and the value on the glossy surface side by an air leakage type paper smoothness meter (Parker print surface roughness) is It is preferably 3.0 μm or less at a pressure of 1.0 Mpa. If it exceeds 3.0 μm, the halftone dot reproducibility at the time of gravure printing is poor and the printing appearance tends to be poor. The smoothness can be adjusted by the raw material freeness and the content of the dryer release agent, and a calendar can be used to obtain a desired smoothness.

  In order to adjust the smoothness by the air leakage method, it is necessary to dry and peel the surface of the decorative board base paper so that it does not become rough when drying with a Yankee dryer. There is also a trade-off, and the content of the sizing agent can be adjusted to 1.0% by weight or less, more preferably by using an externally added release agent, particularly a vegetable release agent in the Yankee dryer.

As described above, the decorative board base paper of the present embodiment is a thin material having a basis weight of 20 to 55 g / m ² , has sufficient concealing properties, and does not generate any stain due to moisture absorption over time. Furthermore, printing aptitude and pasting aptitude to a base material become favorable.

＜試料調整＞ EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In addition, the numerical value of the following weight% is all the numerical value of solid conversion. It shows in Table 1 and Table 2 about the created sample (Examples 1-16, Comparative Examples 1-9).

<Sample preparation>

  As the raw material pulp, hardwood kraft pulp (LBKP) showing the freeness described in Tables 1 and 2 was used in the proportions (% by weight) described in Tables 1 and 2. In Example 13, softwood kraft pulp (NBKP) having a freeness of 550 mL was used together with LBKP.

Chemicals were added to the adjusted raw pulp slurry in the order described below. Titanium oxide (material name (anatase type: manufactured by Titanium Industry Co., Ltd., KA-100, rutile type: manufactured by Teika Co., Ltd., JRNC)), paper strength agent (amphoteric polyacrylamide, manufactured by Seiko PMC Co., Ltd., DS4366), sulfate band (aluminum sulfate ), Sizing agent (material name (rosin emulsion: Harima Kasei Co., Ltd., Hersize NES555, saponified rosin: Arakawa Chemical Industries, Size Pine E, styrene acrylic: Arakawa Chemical Industries, NA size), charge control agent (Sulphonic acid compound, Kurita Kogyo Co., Ltd., High Holder D550) and a yield improver (cationic polyacrylate ester, Kurita Kogyo Co., Ltd., High Holder 220) were used. In Example 9, the paper is fed to a long net multi-cylinder machine) and made to have the basis weight shown in Tables 1 and 2. By, to produce a decorative laminate base paper.
<Evaluation>

  Paper surface pH, smoothness, bump size, and opacity were measured for the decorative board base paper prepared as described above. The pH measurement on the paper surface was carried out using a reagent manufactured by Kyoritsu Riken, Inc., JAPAN TAPPI, Paper Pulp Test Method No. According to 49-2, the Yanki dryer contact surface (surface on which decorative board base paper is printed) was measured. Smoothness is PPS TESTER (SE-115, manufactured by Lorenzen & Bettley Co., Ltd.), soft backing, with a clamping pressure of 1 MPa, according to JIS P 8151. The smoothness of the surface to be applied was measured 5 times, and the average value was obtained. Cobb size (30 seconds) was measured according to JIS P 8140 on the Yanki dryer non-contact surface (surface to be bonded to the base material of the decorative board base paper). The opacity was measured according to JIS P 8138.

（１）シミ
５：シミがまったく無い
４：ごく薄いシミが見えるが、製品化可能
３：薄いシミが斑点状に見えるが、製品化可能
２：全体に薄いシミが見え、製品化不可
１：全体に濃いシミが見え、製品化不可
（２）隠蔽性
◎：化粧板の色ムラが透けて見えない
○：化粧板の色ムラがわずかに透けて見えるが、製品化可能
△：化粧板の色ムラが所々透けて見えるが、製品化可能
×：化粧板の色ムラが全体で透けて見え、製品化不可
（３）印刷適性
◎：白抜けが確認できない
○：白抜けがわずかに確認できるが、製品化可能
△：白抜けが所々確認できるが、製品化可能
×：白抜けが全体で確認でき、製品化不可
（４）貼合適性
◎：貼合時のシワや破れなどの異常なし
○：貼合時のシワや破れが１ヶ所発生するが、製品化可能
△：貼合時のシワや破れが２ヶ所発生するが、製品化可能
×：貼合時のシワや破れが３ヶ所以上発生し、製品化不可
＜結果＞ The above decorative board base paper was allowed to stand for 14 days under conditions of 40 ° C. and 65%, and then the stain was evaluated. Moreover, it printed with the ink containing a pigment with the test gravure printing machine (GP2) with respect to the decorative board base paper produced as mentioned above. After that, the decorative board was manufactured by pasting to a base material MDF coated with vinyl acetate paste by hot pressing. The obtained decorative board base paper was evaluated for concealability, printability and bonding suitability. The evaluation results are shown in Table 3 and Table 4.

(1) Stain 5: No stain at all 4: Appearance is very thin, but can be commercialized 3: Thin stain appears to be spotted, but can be commercialized 2: Thin stain is visible on the entire surface, cannot be commercialized 1: Dark stains are visible on the whole and cannot be commercialized. (2) Concealment ◎: Color unevenness on the decorative board is not visible. ○: Color unevenness on the decorative board is slightly visible, but commercialization is possible. Color unevenness can be seen through in some places, but it can be commercialized ×: Color unevenness on the decorative board can be seen through and cannot be commercialized (3) Printability ◎: No white spots can be confirmed ○: White spots can be slightly confirmed However, it is possible to commercialize △: White spots can be confirmed in some places, but commercialization possible ×: White spots can be confirmed as a whole, and commercialization is not possible (4) Bonding suitability ◎: No abnormalities such as wrinkles or tears at the time of bonding ○: One wrinkle or tear at the time of bonding occurs, but can be commercialized △: Wrinkle or torn at the time of bonding Although it occurs in 2 places, it can be commercialized ×: Wrinkles and tears at the time of bonding occur in 3 or more places and cannot be commercialized <Result>

  It was found that when the content of the sizing agent was 1.0% by weight or less (Examples 1 to 16), the number of spots was reduced (stains 3 to 5). On the other hand, when the content of the sizing agent is 1.3% by weight or more (Comparative Examples 1 and 2), the generation of stains is large and the product cannot be produced (stains 1 and 2). I understood it. From this result, it was found that the decorative board base paper with less stains can be produced by setting the content of the sizing agent to at least 1.0% by weight or less.

  When rosin emulsion is used as a sizing agent (Examples 1 to 8, 11, 12, 15, 16), compared with the case of using other materials (saponified rosin, styrene acrylic emulsion) (Examples 9 and 10). Thus, the occurrence of spots was reduced (Examples 1 to 8, 11, 12, 15, 16: Spot evaluation 4 to 5, Examples 9 and 10: Spot evaluation 3). From this result, it was found that the use of a rosin emulsion as a sizing agent makes it possible to produce a decorative board base paper with less occurrence of spots.

  When the content of titanium oxide is less than 2.5% by weight (Comparative Example 3: 2% by weight), compared with the case of 2.5 to 15% by weight (Examples 1 to 16), in concealment It turned out that there exists a tendency to be inferior (Comparative Example 3: Concealment X) (Examples 1 to 16: Concealment [Delta] to A). Further, when the content of titanium oxide is more than 15% by weight (Comparative Example 4: 18% by weight), the printability tends to be inferior compared with the case of 5 to 15% by weight (Examples 1 to 16). (Comparative Example 4: Printability x) (Examples 1 to 16: Printability Δ to ◎). In addition, it was found that when anatase-type titanium oxide was used (Example 1), compared with the case where rutile-type titanium oxide was used (Example 12), there was a tendency to have excellent concealability (Example). 1: Concealment property ◎) (Example 12: Concealment property ◯). From this result, it was found that a decorative base paper excellent in concealability and printing characteristics can be produced by setting the content of titanium oxide to 5 to 15% by weight and preferably using anatase type titanium oxide.

  When the paper surface pH is 3.2 to 4.8 (Examples 1 to 16), more than 4.8 (Comparative Example 5: 5.0) or less than 3.2 (Comparative Example 6: 3.0) ), It was found that there is a tendency to have better concealment and printability. Therefore, it was found that a decorative board base paper excellent in concealability and printability can be produced by blending a sulfuric acid band so that the paper surface pH is 3.2 to 4.8.

  It was found that when no charge control agent or yield improver was used (Example 11), compared to when it was used (Example 1), in terms of concealability and printability (Example 11: Concealment). Property Δ, printability Δ) (Example 1: concealment property: 、, printability:）). From this result, it is possible to produce a decorative board base paper excellent in concealability and printability by using a charge adjusting agent (main component: sulfonic acid compound) and a yield improver (main component: cationic polyacrylic ester). I understood.

  The decorative board base paper (Comparative Example 9) produced by a long-mesh multi-cylinder paper machine may be inferior in printability compared to the decorative board base paper (Examples 1 to 16) produced by a paper machine having a Yankee dryer. It was found (Comparative Example 9: Printability x, Examples 1 to 16: Δ to A). From this result, it was found that by using a paper machine having a Yankee dryer, a decorative board base paper having excellent printability can be prepared.

In Examples 1-16, it turned out that basic weight will be 20-55 g / m < ² > and paper surface pH will be 3.2-4.8.

As apparent from the above, it is produced by a paper machine having a Yankee dryer, contains a sizing agent of 1.0% by weight or less per bone dry pulp weight, contains 2.5 to 15% by weight of titanium oxide, and has a basis weight of The decorative board base paper having a paper surface pH in the range of 20 to 55 g / m ² and a paper surface pH of 3.2 to 4.8 has a sufficient paper strength while being a thin paper mixed with titanium oxide, is free of spots, and is concealed. It was found that the film was excellent in all of properties, printing suitability, and pasting suitability.

More preferably, it was found that a more preferable decorative board base paper can be obtained by containing 1.6 to 3.5 parts by weight of a sulfuric acid band and further containing a charge adjusting agent and a yield improving agent. .

Claims (6)

In a decorative board base paper manufactured by a paper machine with a Yankee dryer and pasted to a base material as a base paper in a decorative board,
At least titanium oxide is contained, the content of titanium oxide is 2.5 to 15% by weight, the content of sizing agent is 1.0% by weight or less per dry dry pulp,
A decorative board base paper having a basis weight of 20 to 55 g / m ² and a paper surface pH of 3.2 to 4.8.   The decorative board base paper according to claim 1, wherein the sizing agent is a rosin emulsion sizing agent.   The decorative board base paper according to claim 1 or 2, wherein the decorative board base paper contains a charge adjusting agent, and the charge adjusting agent contains a sulfonic acid compound as a main component.   The decorative board base paper according to any one of claims 1 to 3, wherein the decorative board base paper contains a yield improver, and the yield improver comprises a polyacrylate as a main component. .   The decorative board base paper according to any one of claims 1 to 4, wherein the titanium oxide has a crystal structure of anatase type. A method for producing a decorative board base paper to be bonded to a substrate as a decorative board base paper in a decorative board,
Supply pulp material with at least a titanium oxide with a content of 2.5 to 15% by weight and a sizing agent with a content of 1.0% by weight or less per dry pulp to a paper machine with a Yankee dryer Then, the decorative board base paper is manufactured.