JP6427242B1 - Method of producing base paper for ink jet printing, and method of producing thermosetting resin decorative board - Google Patents

Abstract

The present invention relates to a method of producing a base paper for ink jet printing, which is obtained by coating a coating liquid containing amorphous silica and a polymer resin on a decorative board base paper in order to improve the ink jet printability. The invention provides a method of producing a base paper for ink jet printing, which improves the problem of the penetration of coating solution and the wrinkles. The solution is solved by using a polymer resin which does not dissolve in water and dissolves in an organic solvent, and the coating is divided into a plurality of steps and gravure coating is performed. An example of such a polymer resin is cellulose acetate. The printed matter obtained by inkjet printing on the base paper for inkjet printing is impregnated with a thermosetting resin and used for a thermosetting resin decorative board. 【Selection chart】 None

Description

  The present invention relates to a method for producing a decorative base sheet used as a surface decorative material for a thermosetting resin decorative board such as a melamine decorative board, a polyester decorative board, and a Dap decorative board, and a thermosetting resin decorative board. More particularly, the present invention relates to a method for producing an inkjet printing base paper printed by inkjet printing, an inkjet printing base paper produced by the method, and a thermosetting resin decorative board using the inkjet printing base paper.

  Titanium oxide, pigments, dyes and the like are incorporated into the decorative base paper in accordance with the hue in order to conceal the base when molded. In this respect, it is distinguished from the overlay base paper used for the outermost layer of the thermosetting resin decorative board. The overlay base paper needs to be excellent in transparency when molded.

  Decorative board base paper is roughly classified into white base paper and color base paper in terms of its hue. Although the concealability of the decorative base paper is generally imparted by milling titanium oxide, the concealability can also be imparted depending on the hue. For example, titanium dioxide is not incorporated into black base paper, and a black pigment or a black dye is incorporated to give hiding power. The concealing property in the present specification means the property of concealing the hue and uneven hue of the base when it is made a thermosetting resin decorative board.

  On the other hand, overlay base paper is mainly used to protect decorative board base paper, and when molded, it is required to have transparency which does not impair the color of decorative board base paper and the design of printed patterns. Therefore, titanium oxide and pigments are not incorporated. The ash content of the overlay base paper is substantially 0%.

  Finally, it is laminated with other members in a state in which the thermosetting resin is impregnated, and is heat and pressure molded to be processed into a thermosetting resin decorative board. Accordingly, the decorative base paper and the overlay base paper are required to be impregnated with thermosetting resin. In the present specification, the impregnation suitability refers to the permeation speed of the thermosetting resin. A slow penetration speed of the thermosetting resin affects the productivity of the impregnation process. The decorative base sheet and the overlay base sheet are non-size-treated special papers which are not subjected to size processing using a sizing agent because they are impregnated with a large amount of resin.

  Printing of a wood grain pattern, an abstract pattern or the like on the decorative board base paper is applied to give the thermosetting resin decorative board a design. Gravure printing is the mainstream printing method. Since gravure printing is not suitable for small volume production, printing on decorative board base paper by inkjet printing is also performed.

  For example, in patent document 1, in order to improve the inkjet printability of decorative board base paper, the coating liquid of the water only solvent containing amorphous silica and a polymer resin is coated on the front surface of decorative board base paper. Decorative base paper for ink jet printing has been proposed. The coating method is not particularly limited, and a gravure coating method is also described as an example. However, the coating method of the example is not the gravure coating method.

  In patent document 2, applying a coating liquid to a decorative board base paper by a curtain coat system is proposed. In the examples, it is described that it is difficult to damage the impregnating ability of the melamine resin if the curtain coating method is applied as compared with the blade coating method. The coating solution uses a coating solution of a single solvent of water containing amorphous silica and a polymer resin.

  Further, Patent Document 3 proposes coating a coating liquid containing amorphous silica, a nonionic emulsion and a cationic ink fixing agent on a decorative board base paper. Although a coating system is not specifically limited, There is no illustration of a gravure coating system. In the embodiment, a wire bar coating method is used.

  In addition, in Patent Document 4, nanofibrillated cellulose is used in the ink receiving layer, but in the present invention, nanofibrillated cellulose is not an essential component.

JP 2000-335105 A US2008 / 0090032A1 Patent No. 5730823 gazette Special Table 2015-527217

  Since the decorative base paper does not have the size treatment of internal addition size or surface size using sizing agent, when a coating solution of water only solvent is applied, the coating solution becomes easy to fall off because the size is not treated . The lower the basis weight of the base paper and the greater the coating amount, the more likely the coating liquid to be punched through. In addition, the paper stretches to make it easy to get wrinkles. The lower the basis weight of the base paper and the greater the coating amount, the easier it is for the wrinkles to get in, making it difficult to adjust at the time of coating. Therefore, in actual production, it is necessary to take measures against strikethrough and wrinkles. Patent Literatures 1 to 4 do not mention strike-through and wrinkles during coating and drying.

The present invention is a method for producing a base paper for ink jet printing, which is obtained by applying a coating liquid containing a polymer resin to a decorative base paper which has not been subjected to a sizing process in order to improve the ink jet printability. An object of the present invention is to provide a method for producing a base paper for ink jet printing, which can solve the problem of the coating liquid passing through and the wrinkles at the time of processing. Another object of the present invention is to provide a method of producing a thermosetting resin decorative board using the base paper for ink jet printing produced by this production method .

The method for producing an inkjet printing base paper according to the present invention, which solves the above object, is for inkjet printing formed by coating a coating liquid containing amorphous silica and a polymer resin on a decorative board base paper which has not been subjected to sizing treatment . A method of producing a base paper,
A coating liquid adjusting step of adjusting the coating liquid using the polymer resin which is not dissolved in water and dissolved in a solvent comprising an organic solvent;
And a coating step of gravure coating the coating liquid on the decorative sheet base paper a plurality of times using a gravure coating method ,
The coating solution adjusting step, wherein the step der Rukoto using cellulose acetate as the polymer resin.

  Here, the polymer resin which does not dissolve in water and dissolves in a solvent composed of an organic solvent does not include, for example, partially benzalized polyvinyl alcohol which dissolves in a mixed solvent of water and an organic solvent. Moreover, in the coating step, the coating liquid applied for each gravure coating may be dried. Furthermore, in the coating step, the same coating liquid may be gravure coated a plurality of times, and in the coating liquid adjusting step, the combination of the polymer resin, the polymer resin, and the amorphous silica A plurality of types of coating liquids having different proportions may be prepared, and different coating liquids may be applied for each gravure coating.

Further, in the method of producing a base paper for inkjet printing of the present invention, the coating step is 0.6 to 2.0 g / m ² as a dry coating amount in one gravure coating and 3 as a dry total coating amount It is preferable that it is a step of applying to 6 g / m ² .

Here, the dry total coating amount is more preferably ⁴ to 5 g / m ² . Further, in the coating step, the dry coating amount of one gravure coating may be made uniform, or the dry coating amount may be made different for each gravure coating.

  As the polymer resin, cellulose nitrate or urethane resin may be used instead of, or together with cellulose acetate.

  Further, in the method of producing an inkjet printing base paper of the present invention, the coating step is preferably a step of gravure coating using a gravure printer having a plurality of printing units used for multicolor printing.

Furthermore, in the method for producing a base paper for inkjet printing of the present invention, the coating liquid adjusting step comprises polymer resin / amorphous silica as a blend ratio of the polymer resin and the amorphous silica in the coating liquid. It is preferable that it is a process adjusted to the range of 2 / 8-5 / 5.

The method for producing a thermosetting resin decorative board according to the present invention, which solves the above object, comprises inkjet printing on the gravure coated side of an ink jet printing base sheet produced by any of the above-described ink jet printing base sheet production methods. A first step of applying a surface cosmetic material;
And a second step of processing the surface decorative material into a thermosetting resin decorative board .

According to the invention
1) The problem of the penetration of the coating liquid is improved by dividing and coating a plurality of times with a gravure printer.
2) By using a polymer resin which does not dissolve in water and dissolves in a solvent composed of an organic solvent as the polymer resin, the problem of wrinkles at the time of coating and drying is improved. Specifically, pulp, which is a raw material of a decorative base material to be a coating base, is hydrophilic since it is mainly composed of cellulose fibers having a large number of hydrophilic groups, and absorbs a solvent composed of a hydrophobic organic solvent. Hateful. For this reason, compared with water alone or a mixed solvent of water and an organic solvent, the solvent composed of the organic solvent is less likely to be absorbed by the cellulose fiber, and does not swell and does not extend. As a result, at the time of coating and drying, wrinkles are less likely to occur on the decorative sheet base paper.
3) Since water of large latent heat is not used as a solvent, the solvent can be removed with low energy and in a short time.

  Hereinafter, the present invention will be described in order.

  In the present invention, a decorative base paper is used as a base paper to be a base. The raw materials and the physical properties of the decorative board base paper are based on the conventional decorative board base paper, and are not particularly limited.

  Decorative board base paper includes various pulps such as LBKP, NBKP, etc., fillers such as titanium oxide according to color, pigments, dyes, wet strength agents, sulfuric acid bands, sodium aluminate, retention aids, etc. It can be obtained by making a paper stock containing an additive with a Fourdrinier paper machine or the like. In addition, the decorative board base paper is a special paper which is not subjected to size processing of internal addition size and surface size using a sizing agent.

The basis weight of the decorative base paper is generally in the range of 50 to 110 g / m ² . The ash content of the decorative base paper is generally 20 to 40% by mass except for special ones such as black base paper. In the case of white base paper, the ash content generally corresponds to the content of titanium oxide and is an index of shielding power. The decorative board base paper can also be designed to improve smoothness by smoothing processing using a calendar.

  Next, the coating liquid adjustment process of the present invention for adjusting a coating liquid containing amorphous silica and a polymer resin will be described.

  The polymer resin used in the present invention is insoluble in water and soluble in a solvent comprising an organic solvent. Examples of such a polymer resin include cellulose acetate, cellulose nitrate, and urethane resin.

  The organic solvent used in the present invention is not particularly limited as long as it can dissolve the polymer resin. For example, acetone, methyl ethyl ketone, ethyl acetate, propylene glycol monomethyl ether may be mentioned.

  In the present invention, amorphous silica is blended in the coating solution. The amorphous silica is not particularly limited as long as it is a commercially available ink jet receiving layer.

  Furthermore, additives such as a dispersant, an antifoamer, a thickener, and an ink fixing agent can be added to the coating liquid, if necessary.

  The blending ratio of the polymer resin / amorphous silica in the coating liquid is preferably in the range of 2/8 to 5/5. If the blending amount of the polymer resin as the binder is small, it tends to be difficult to hold the amorphous silica, and there is a possibility that powdering may occur. If the blending amount of the polymer resin is large, the impregnation property of the thermosetting resin tends to be deteriorated.

The total dry coat weight of the coating liquid (solid content), preferably ^{3~6g / m 2, 4~5g / m} 2 is more preferable. If the dry total coating amount is small, sufficient color developability tends not to be obtained. When the dry total coating amount is large, the impregnation property of the thermosetting resin tends to be deteriorated.

  The coating process of the present invention is carried out using the coating liquid prepared by the coating liquid adjusting process as described above. At a coating process, it coats so that it may become a predetermined | prescribed dry total coating amount by several times of coating on a decorative board base paper by a gravure coating system.

As one dry coating amount by gravure coating of a coating liquid, 0.6-2.0 g / m < ² > is preferable. When the dry coating amount is small, the number of times of gravure coating increases, so that the amount affects the productivity. As the dry coating amount increases, it takes time to dry.

  As a viscosity of a coating liquid, in the case of Iwata cup NK-2, viscosity (25 degreeC) is preferably 12 to 17 seconds, and more preferably 14 to 15 seconds. Zaan cup No. In the case of 3, the viscosity (25 ° C.) is preferably 12 to 23 seconds, and more preferably 15 to 20 seconds. If the viscosity is too low or too high, it will not be suitable for gravure coating.

  A solid coating plate can be used in the coating process, and the cell shape of the gravure of this solid coating plate is not particularly limited, and those generally used for coating such as helio type are applied it can. The number of cell lines, cell diameter and cell depth may be selected according to the solid content concentration of the coating liquid, the amount of coating, and the like.

  In the coating process, a gravure printing machine having a plurality of printing units used for multicolor printing is suitably used because the coating is performed a plurality of times by the gravure coating method. Among such gravure printing presses, the specifications of the gravure printing press used for gravure printing of decorative sheet base paper are more preferable. It is not always necessary to unify the solid printing plate shape of the gravure cylinder of the printing unit.

  A top coat may be further provided on the coating layer composed of amorphous silica and the polymer resin for the purpose of compensating for the strength. The coating solution for the top coat includes cellulose acetate in the solvent system and casein in the water system, but it is not particularly limited as long as it does not affect the ink jet printability and the thermosetting resin impregnation property.

  Furthermore, after the coating liquid is applied and dried, a smoothing treatment using a calender can be applied to the coated surface side.

  The base paper for ink jet printing obtained as described above is subjected to printing by ink jet printing on the coated surface side. The inkjet printing method is not particularly limited. The ink is also not particularly limited. For example, as the pigment ink, either a solvent-based pigment ink or an aqueous pigment ink may be used. In addition, a UV curable ink can also be used.

  The thermosetting resin decorative board of the present invention is a thermosetting resin decorative board by a method known as a surface decorative material, a printed material on which the ink jet printing is performed on the coated surface side of the base paper for ink jet printing obtained as described above. Processed into The thermosetting resin decorative board of the present invention is not particularly limited, and can be applied to, for example, a high pressure melamine decorative board, a low pressure melamine decorative board, a polyester decorative board, a dap decorative board, and the like.

  Hereinafter, the present invention will be described in detail by way of examples. Parts and% indicate parts by mass and% by mass.

First, a method of producing an inkjet printing base paper will be described.
<Baseboard for decorative board>
In the present example, as the decorative base paper serving as the coating base, product product numbers KW-801P and KCW-801P, which are white paper sheets for printing of 80 g / m ² manufactured by KJ Specialty Paper Co., Ltd., were used. The basis weight of KW-801P used was 82 g / m ² , the smoothness was 60 seconds on the front side / 38 seconds on the back side, the air permeability was 21 seconds, and the ash content was 32%. The basis weight of KCW-801P was 79 g / m ² , the smoothness was 64 seconds on the front side / 27 seconds on the back side, the air permeability was 20 seconds, and the ash content was 40%.

The coating liquid adjustment process will be described.
Preparation of Coating Liquid 1: Used in Examples 1 to 3 and Comparative Example 6
The coating liquid 1 dissolves 6.0 g of a cellulose acetate resin / additive in 84.9 g of a mixed solvent of propylene glycol monomethyl ether, methyl ethyl ketone, diacetone alcohol, butyl acetate and ethyl acetate, and further amorphous silica 9 .1g was added and it was set as the coating liquid. The resin / silica solid content ratio of the coating liquid is approximately 4/6. The solid content concentration of the coating liquid was about 15%, and the viscosity at printing when this was diluted with an organic solvent was 14 to 15 seconds (25 ° C.) at Iwata cup.

Preparation of Coating Liquid 2: Used in Examples 4 and 5
Coating solution 2 dissolves 10 g of cellulose acetate resin / additive in 75 g of mixed solvent of acetone, methyl ethyl ketone, diacetone alcohol and propylene glycol monomethyl ether acetate, and further 7.5 g of amorphous silica, precipitated barium sulfate 7.5g was added and it was set as the coating liquid. The ratio of resin / silica in the coating solution is approximately 6/4. The solid content concentration of the coating liquid is approximately 25%, and the viscosity at the time of printing when this is diluted with an organic solvent is Zahn cup No. The viscosity at 25 (25 ° C) was 18-19 seconds.

Preparation of Coating Liquid 3: Used in Comparative Examples 3 and 7
In coating liquid 3, 8.4 g of amorphous silica is dispersed in 84 g of water with a stirrer, and 1.2 g of a cationic ink fixing agent (30% concentration) is added, followed by ethylene vinyl acetate emulsion as a polymer resin (It was prepared by adding 6.5 g of a concentration of 55%, nonionic emulsion) (solid content ratio of resin / silica of coating liquid is about 3/7). The solid content concentration of the coating liquid is 12%. The viscosity at 25 (25 ° C.) was 17 seconds.

Preparation of Coating Liquid 4: Used in Comparative Examples 4 and 5
The coating liquid 4 is dispersed in 66 g of water and 44 g of industrial ethyl alcohol (containing 15% isopropyl alcohol) with 16.4 g of amorphous silica by means of a stirrer, followed by partially benzalized polyvinyl alcohol (solid content 8) as a polymer resin. It prepared by adding 23g of mass%, 55 mass% of water, and 37 mass% of isopropyl alcohol (therefore, the solvent composition of a coating liquid becomes water / ethyl alcohol / isopropyl alcohol = 60/28/12. This solvent composition) However, the partially benzalized polyvinyl alcohol is dissolved, and the resin / silica solid content ratio of the coating liquid is approximately 1/9). The solid content concentration of the coating liquid is 12%. The viscosity at 25 (25 ° C.) was 19 seconds.

The coating process will be described.
Gravure coating of coating solution
The gravure coating of the said coating liquid to the decorative board base paper used as a base was performed as follows. A base plate for the decorative plate as a base is cut, and a commercially available PPC paper is placed under the base plate for the decorative plate as a base, and the above-mentioned coating liquid is a gravure printing test machine (trade name GP-2 (made by Kurashiki Spinning Co.)) Plate for Helio-type solid printing (54 L, 230 μm, 11 cm × 13 cm: Gravure cell line number is 54 lines / cm, cell diagonal length is 230 μm, solid plate printing range is 11 cm × Gravure coating was carried out at 13 cm and dried for each gravure coating.

  The evaluation method of this example was performed by the following method.

(1) Evaluation of coating and drying of coating liquid <throughout of coating liquid>
After applying the coating liquid, the presence or absence of the strike-through to the surface in contact with the back surface of the coated paper was evaluated. The case where there is no strike-through is regarded as good (○), and the case where the strike-through is not accepted (×).

<Evaluation of wrinkles of coated material>
After repeating coating and drying of the number of times of coating described in each example and comparative example, the presence or absence of wrinkles was checked. Ten pieces of each were prepared, and it was regarded as good (○) when no wrinkles were entered as well as not possible (×) when wrinkles were inserted even in one of ten pieces.

<Dropout evaluation of coated materials>
The retention as a binder was evaluated by powdering.

  The prepared coated sample was cut into 10 × 5 cm, placed on a black paper with the coated side facing down, and a 2 kg weight (weight of a balance) was placed thereon, and it was reciprocated one time. The weight and the sample were removed, and it was regarded as good (o) when the black powder did not have white powder, and not possible (x) when it was.

  (2) The thermosetting resin impregnating property (hereinafter referred to simply as impregnating property) of inkjet printing base paper which is not ink jet printing uses 55% aqueous solution of melamine resin for high pressure melamine decorative board as thermosetting resin After adjusting the temperature to 20 ° C., the paper was penetrated from the ink jet printing side of the paper, and visually observed until the melamine resin uniformly penetrated to the opposite side of the paper, and the time taken was measured with a stopwatch. The measured time may be hereinafter referred to as the impregnation time. The lower the value of the impregnation time, the better the impregnation of the melamine resin. In the evaluation of the impregnation, the impregnation time was good (○) for less than 70 seconds, good (可) for 70 seconds or more and less than 120 seconds, and not possible (×) for 120 seconds or more. Although good (△) in the evaluation of the impregnatability does not have any problem in practical use, it shows a slightly inferior impregnatability to the good (〇).

Next, the thermoplastic resin decorative board will be described.
(3) Ink jet printing aptitude The solid ink was printed using pure water-based pigment ink using PX-105 (manufactured by Seiko Epson Corporation) for the ink jet printer. Using this printed matter, a decorative board was produced by the method described later, and the print finish on the decorative board was evaluated.

<Preparation of high-pressure melamine decorative board: When printed on decorative board base paper>
Printed matter is hand-impregnated in an impregnation solution of 55% solution in which 100 parts of melamine resin for high-pressure melamine decorative board, 0.2 parts of curing agent and 1 part of penetrant are dissolved in water, and the impregnation rate is 100 to 130 based on printed matter. % Melamine resin impregnated printed matter was obtained.

  Next, core paper impregnated with a phenol resin (trade name: Ota Core (manufactured by Ota Sangyo Co., Ltd.)) is coated on the overlay paper impregnated with a melamine resin (trade name: Melamine impregnated overlay paper (manufactured by Ota Sangyo Co., Ltd.)). 4 sheets, further overlaying the above-mentioned printed matter impregnated with melamine resin, overlaying overlay paper impregnated with melamine resin (trade name: melamine impregnated overlay paper (manufactured by Ota Sangyo Co., Ltd.)), and heating and pressing The machine was heated and pressed to obtain a high pressure melamine decorative board.

<Color development evaluation: Evaluation with colorimetric a value>
The coloring property of the printing finish of the produced decorative plate was evaluated by measuring the hue with a Macbek spectrophotometer: CE-3100 (manufactured by Sakata Inx Engineering Co., Ltd.). The a value measured was determined to be good (○) at 57 or more, acceptable (Δ) at 53 or more and less than 57, not possible (X) at less than 53. In the evaluation of color developability, good (Δ) indicates a color developability slightly inferior to good (O), although there is no problem in practical use.

Example 1
The coating solution 1 was applied five times on the front surface of the base decorative paperboard KCW-801P with a solid printing plate using a gravure printing tester. The total dry coating amount was 4.4 g / m ² . Furthermore, as a top coat, 0.3 g / m ² of casein was applied by a gravure printer. There was no penetration of the coating solution. The number of coated samples containing wrinkles was 0 out of 10, and the evaluation of wrinkles was also good (o). There was no powder loss. The impregnation time was 42 seconds, and the impregnation was also good (o). The a value was 59 and the color developability was also good (o).

(Example 2)
The coating solution 1 was applied five times on the front surface of the base decorative paperboard KCW-801P with a solid printing plate using a gravure printing tester. The total dry coating amount was 4.2 g / m ² . Furthermore, 0.3 g / m ² of cellulose acetate was coated by a gravure printer as a top coat. There was no penetration of the coating solution. The number of coated samples containing wrinkles was 0 out of 10, and the evaluation of wrinkles was also good (o). There was no powder loss. The impregnation time was 61 seconds, and the impregnation was also good (o). The a value was 58, and the color developability was also good (o).

(Example 3)
The coating liquid 1 was applied five times on the front surface of the base decorative paper sheet KW-801P with a solid printing plate using a gravure printing tester. The total dry coating amount was 5.1 g / m ² . Furthermore, as a top coat, 0.3 g / m ² of casein was applied by a gravure printer. There was no penetration of the coating solution. The number of coated samples containing wrinkles was 0 out of 10, and the evaluation of wrinkles was also good (o). There was no powder loss. The impregnation time was 53 seconds, and the impregnation was also good (o). The a value was 57, and the color developability was also good (o).

(Example 4)
The coating liquid 2 was applied three times on the front surface of the base decorative paper sheet KW-801P with a solid printing plate using a gravure printing tester. The dry coating amount was 3.1 g / m ² . There was no penetration of the coating solution. The number of coated samples containing wrinkles was 0 out of 10, and the evaluation of wrinkles was also good (o). There was no powder loss. The impregnating time was 106 seconds, and the impregnating property was acceptable (Δ) although there was no problem in practical use. The a value of the color forming property was 55, and the color forming property of the material having no problem in practical use was acceptable (Δ).

(Comparative example 1)
The ink jet printing was performed as it was on the front surface of the base decorative paper base KW-801P. The impregnation time was 24 seconds, and the impregnation property was good (o). On the other hand, the a value was 50, and the color developability was not possible (x).

(Comparative example 2)
The ink jet printing was carried out as it was on the front surface of the base decorative base paper KCW-801P. The impregnation time was 18 seconds, and the impregnation property was good (o). On the other hand, the a value was 49, and the color developability was not possible (x).

(Comparative example 3)
The coating liquid 3 was applied five times on the front surface of the base decorative paper sheet KW-801P with a solid printing plate using a gravure printing tester. The dry coating amount was 4.6 g / m ² . There was no penetration of the coating solution. There were three coated samples containing 10 wrinkles, and the wrinkle evaluation was not possible (x). There was no powder loss. The impregnation time was 35 seconds, and the impregnation property was good (o). The a value was 57 and the color developability was good (o).

(Comparative example 4)
The coating liquid 4 was applied six times with a solid printing plate using a gravure printing tester on the front surface of the base decorative paper sheet KW-801P. The dry coating amount was 6.6 g / m ² . There was no penetration of the coating solution. There were two coated samples containing 10 wrinkles, and the wrinkle evaluation was not possible (x). There was powdering, and the powdering evaluation was not possible (x). The impregnation time was 114 seconds, and the impregnation was acceptable (Δ). The a value was 61 and the color developability was good (o).

(Comparative example 5)
The coating solution 4 was applied five times on the front surface of the base decorative paper sheet KW-801P with a solid printing plate using a gravure printing tester. The dry coating amount was 5.2 g / m ² . Furthermore, as a top coat, 0.3 g / m ² of casein was applied by a gravure printer. There was no penetration of the coating solution. There were 1 out of 10 coated samples containing wrinkles, and the wrinkle evaluation was not possible (x). There was no powder loss. The impregnation time was 142 seconds, and the impregnation was not possible (x). The a value was 61 and the color developability was good (o).

(Comparative example 6)
The coating liquid 3 was coated once with a wire bar on the front surface of the base decorative paperboard KCW-801P. The dry coating amount was 5.0 g / m ² . The coating liquid fell through, and the evaluation of the through was not possible (x). The number of coated samples containing wrinkles was 7 out of 10, and the wrinkle evaluation was also not possible (x). There was no powder loss. The impregnation time was 40 seconds, and the impregnation property was good (o). The a value was 61 and the color developability was good (o).

  Table 1 shows the evaluation results of Examples 1 to 4.

  Table 2 shows the evaluation results of Comparative Examples 1 to 3.

  Table 3 shows the evaluation results of Comparative Examples 4 to 6.

  The above evaluation results are summarized as follows.

  1) The problem of the strike-through of the coating liquid is improved by coating a plurality of times with a gravure printing tester (Examples 1 to 4 for Comparative Example 6).

  2) However, when gravure printing is repeated with a coating liquid using an emulsion as a polymer resin, wrinkles are easily caused (Comparative Example 3).

  3) The problem of wrinkles is also complete by gravure coating using partially benzalized polyvinyl alcohol (polymer resin that does not dissolve in water and dissolves in an aqueous mixed solvent consisting of water and alcohol) as the polymer resin. Was not solved (Comparative Examples 4 and 5).

  4) The problem of wrinkles was solved by gravure coating using cellulose acetate (polymer resin which does not dissolve in water and dissolves in an organic solvent) as the polymer resin (Examples 1 to 4).

  5) In Example 4, the coating liquid 2 in which the resin / silica mixture ratio was adjusted to approximately 6/4 was used, and although it is in a range that causes no problem in practical use, the impregnating property is slightly deteriorated. As described above, when the blending amount of the polymer resin is large, the impregnation property of the thermosetting resin tends to be deteriorated, and in the example 4, the impregnating performance is slightly deteriorated in the example 4 because the blending amount of the polymer resin is a little large It is guessed that In order to make the impregnation property good, it is preferable to adjust the blending ratio of resin / silica in the coating liquid to 5/5 or less.

6) Moreover, in Example 4, the dry total coating amount is 3.1 g / m ² , and the coloring property is slightly deteriorated. As described above, there is a tendency that sufficient color development can not be obtained when the total dry coating amount is small, and it is presumed that the reason for the slight deterioration in color developability in Example 4 is that the total dry coating amount is small. . In order to obtain color development more sufficiently, it is more preferable to make dry total coating amount 4 g / m < ² > or more.

  7) In Comparative Example 4 using the coating liquid 4 in which the ratio of resin / silica was adjusted to approximately 1/9, the amount of the polymer resin blended was too small, and the retention as a binder was reduced, and powder fall off Is occurring. In addition, even if it is a case where the same coating liquid 4 as Comparative Example 4 is used, in Comparative Example 5 in which the top coat is applied, the powdering evaluation was acceptable (o). The cause is presumed to be that the top coat was applied, but since the top coat was applied, the impregnation property was deteriorated and became unacceptable (x). In order to prevent powder removal without applying a top coat, it is preferable to adjust the compounding ratio of resin / silica in the coating liquid to 2/8 or more.

  The base paper for ink jet printing obtained by the present invention can be expected to be used as a high pressure melamine decorative board using an ink jet printed material as a surface cosmetic material. In addition to high-pressure melamine decorative boards, development to low-pressure melamine decorative boards, polyester decorative boards, and Dap decorative boards can be expected.

Claims (5)

A method for producing a base paper for ink jet printing, which comprises coating a coating liquid containing amorphous silica and a polymer resin on a decorative base paper which has not been subjected to sizing treatment ,
A coating liquid adjusting step of adjusting the coating liquid using the polymer resin which is not dissolved in water and dissolved in a solvent comprising an organic solvent;
And a coating step of gravure coating the coating liquid on the decorative sheet base paper a plurality of times using a gravure coating method ,
The coating solution adjusting step, the manufacturing method of the ink jet printing sheet, wherein step der Rukoto using cellulose acetate as the polymer resin. Characterized in that said coating step, 0.6~2.0g / ^{m 2} as a dry coating amount in one gravure coating, drying the total coating amount as 3 to 6 g / ^{m 2} coated to step A method of producing an ink jet printing base paper according to claim 1 The coating step, the manufacturing method according to claim 1 or 2 jet printing sheet according to characterized in that the step you gravure coating using a gravure printing machine having a plurality of printing units used in the multi-color . A step of adjusting the coating liquid / amorphous silica in a range of 2/8 to 5/5 as a blending ratio of the polymer resin and the amorphous silica in the coating liquid The method for producing an ink jet printing base paper according to any one of claims 1 to 3, which is characterized in that A first step of subjecting an ink jet printing base sheet manufactured by the method for manufacturing an ink jet printing base sheet according to any one of claims 1 to 4 to gravure-coated side to obtain a surface cosmetic material by ink jet printing.
And a second step of processing the surface decorative material into a thermosetting resin decorative board.