JPH04300399A - Cast-coated patterned paper - Google Patents

Abstract

PURPOSE:To obtain the subject coated paper excellent in printing properties and useful as a packaging paper, etc., by forming a cast coating layer composed of a pigment, an adhesive, etc., on a substrate having a pattern shape due to difference in gloss, bonding it under pressure on the mirror-gloss surface of a heating drum in a wet state and then drying it for finishing. CONSTITUTION:An objective coated paper obtained by using a substrate the surface of which contains high-gloss parts and low-gloss parts having respective gloss degrees (Hg) and (Lg) measured by a method comforting to JIS P8142 and satisfying formula 0.2<=Lg/Hg<=0.9 as the substrate mentioned below, in a cast coated patterned paper produced by forming a cast coating layer mainly composed of a pigment such as clay and an adhesive such as casein or mainly composed of an adhesive on a substrate such as a base paper, bonding it under pressure on the mirror-gloss surface of a heating drum while the coating layer is in a wet state and drying it for finishing.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a patterned cast coated paper, in particular a support having a high-gloss area and a low-gloss area as a support, the difference in gloss being recognized as a pattern. Regarding patterned cast coated paper using.

0002

[Prior Art] In recent years, printed matter has become more sophisticated, visualized,
Coated paper with excellent printing properties and printing effects, especially cast coated paper, has been widely used because of its excellent appearance and printing properties. In particular, demand for patterned cast-coated paper is increasing for uses such as packaging paper and posters.

[0003] Such a patterned cast coated paper is produced by forming a coating layer containing pigment and adhesive as main components on a support whose surface has a pattern formed by unevenness, and then forming a coating layer mainly composed of pigment and adhesive. A method of applying pressure to the surface of a heated metal drum that has a specular luster while it is still in the state, and drying it to give it a strong glossy finish (Japanese Patent Laid-Open No. 5
No. 3-24407) is known. In this method, irregularities of 3 to 100 μm are provided on the surface of the support to form a patterned base paper, and a cast coating liquid is applied onto the patterned base paper to cause unevenness in the amount of coating due to the cast coating liquid. This is a method of finishing the cast. Such a method is certainly
Patterns are created by uneven coating amounts, but due to uneven drying due to uneven coating amounts, the coating layer picks on the surface of the heated metal drum, a so-called drum pick phenomenon, which is caused by stable continuous operation. It was difficult to obtain cast paper.

0004

[Problem to be solved by the invention] From the above-mentioned actual situation,
The inventors of the present invention have conducted extensive research in order to eliminate the drum pick phenomenon, which is a problem when producing patterned cast paper, and to achieve stable operation. By using a support that has glossy areas and the difference in gloss can be recognized as a pattern, patterned cast coated paper has excellent continuous productivity, and has high smoothness, strong gloss, and a unique texture. It has become clear that it can be obtained.

[0005]

[Means for Solving the Problems] The present invention forms a pigment and an adhesive, or a cast coating layer mainly composed of an adhesive, on a support, and provides a specular gloss while the coating layer is in a wet state. In patterned cast coated paper that is finished by pressing and drying on the surface of a heated drum having
P8142, the relationship between the glossiness (Hg) of the high-gloss area and the glossiness (Lg) of the low-gloss area satisfies the following formula [1]. It is a cast coated paper with a pattern. 0.2≦Lg÷Hg≦0.9 [1]

0006
]

[Operation] The support used in the present invention, that is, the support with a pattern based on difference in gloss, is a support whose surface is partially brushed to create a difference in gloss, or a support whose surface is coated with a super calender. A support that has been given a surface gloss by pressure and friction treatment such as the like, and then passed through a partially roughened hard roll to create a difference in gloss, or between a nip consisting of an embossing roll and an opposing roll. There is a patterned support obtained by passing a base material so that the back side of the base material is on the embossing roll side. In particular, the support used in the present invention has a surface with small irregularities and a glossy pattern (
It is important that the pattern is created by a difference in depth, and if the support is patterned with a depth of unevenness, the desired excellent effect of the present invention cannot be obtained.

[0007] The base material of the support used in the present invention includes, for example, base paper made from natural pulp as a main component, and nonwoven fabric obtained by chemically, mechanically, or thermally treating fiber aggregates. , a microporous film obtained by stretching a synthetic resin, or a base paper, nonwoven fabric, or film of these materials provided with a coating layer containing a pigment and an adhesive as main components. In particular, in order to more clearly express the pattern due to the difference in gloss as a support, it is preferable to use a base paper whose surface is provided with an undercoat layer mainly composed of a pigment and an adhesive. Hereinafter, the case where a coating base paper is used as a base material for a support will be described.

[0008] The support used in the present invention is as follows:
It is necessary that the relationship between the glossiness Hg (%) of the high-gloss part of the support surface and the glossiness Lg (%) of the low-gloss part on the surface of the support according to the JIS P8142 method satisfies the following formula [1]. 0.2≦Lg÷Hg≦0.9 [1] In the formula [1], if the Lg÷Hg value exceeds 0.9, the pattern of the resulting cast coated paper will become unclear. On the other hand, 0
．． If it is less than 2, there is a concern that drum picks will occur during the production of cast paper. Therefore, the preferable conditions for obtaining a pattern based on the difference in gloss as a support are Lg
It is important that the ÷Hg value is adjusted to be in the range of 0.2 to 0.9. It is presumed that the cause of drum picks is that the air permeability of the high-gloss area and the air permeability of the low-gloss area are significantly different.

Furthermore, as preferable conditions for obtaining cast paper with a clearer pattern, it is desirable to satisfy the following specific requirements. That is, the ratio of the pigment solid content to the total solid content of the cast coating layer is p, the coating amount of the cast coating layer is w (g/m2: absolute dry weight), and the glossiness of the high gloss area on the surface of the support is Hg. (%), gloss level Lg of low gloss area
(%), it is desirable to adjust these relationships so that they satisfy the following formula.

0≦p×w×Lg÷Hg≦10 [
2] More preferably, 0≦p×w×Lg÷Hg≦8 [3] [2]
In the formula, when the value of p×w×Lg÷Hg exceeds 10, the transparency of the cast coating layer decreases, the pattern becomes unclear, and the commercial value decreases.

As mentioned above, the patterned cast coated paper of the present invention has a high gloss area and a low gloss area on the surface, and the difference in gloss is recognized as a pattern, and furthermore, the patterned cast coated paper as specified above has a high gloss area and a low gloss area, and the difference in gloss is recognized as a pattern. A casting coating layer containing pigment and adhesive, or adhesive as main components, is formed on the support using a coating material, and while the coating layer is in a wet state, it is applied to the surface of the heated drum having a specular gloss. It is pressed and dried to obtain patterned cast coated paper. In this case, the method of forming the cast coating layer obtained by applying pressure to the surface of the heating drum and drying is not particularly limited, and generally known casting methods may be used, such as coating a cast coating liquid onto the support. While the coating layer has fluidity, it is immediately pressed against the surface of a heated drum, dried, and released from the mold (wet casting method), or after applying a cast coating liquid, the coating layer is left in a wet state and subjected to a coagulation effect. A method of gelling the product by passing it through a bath containing a liquid and then drying and releasing it by pressing it against the surface of a heated drum (gelling casting method), or after coating the support with a cast coating solution, There are methods such as once drying, re-wetting and plasticizing the coating layer with a wetting liquid, and then pressing it against the surface of a heated drum, drying, and releasing the mold (re-wet casting method), and any method may be used. .

[0012] In the present invention, the coating composition for the undercoat layer contains pigments and adhesives as main components, similar to conventional coated paper compositions.

Examples of pigments include clay, kaolin,
aluminum hydroxide, calcium carbonate, titanium dioxide,
One or more types of ordinary pigments for coated paper, such as barium sulfate, zinc oxide, satin white, and plastic pigments, are appropriately selected and used. Examples of adhesives include proteins such as casein, soybean protein, and synthetic proteins, conjugated diene polymer latex such as styrene-butadiene copolymer, and polymers or copolymers of acrylic esters and/or methacrylic esters. acrylic copolymer latex, vinyl copolymer latex such as ethylene/vinyl acetate copolymer, or alkali-soluble or alkali-non-alkaline latex modified with a monomer containing a functional group such as a carboxyl group. Soluble polymer latex, polyvinyl alcohol, olefin/maleic anhydride resin, synthetic resin adhesives such as melamine resin, starches such as positive starch and oxidized starch, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, etc. One or more adhesives for coated paper may be appropriately selected and used.

[0014] Furthermore, various auxiliary agents such as antifoaming agents, coloring agents, mold release agents, flow modifiers, etc. may be appropriately blended into the coating composition as required.

[0015] The thus prepared undercoat coating liquid can be applied to coatings used in generally known coated paper production, such as a blade coater, an air knife coater, a roll coater, a reverse roll coater, a bar coater, a curtain coater, a die slot coater, and a gravure coater. The dry weight of
It is adjusted and coated within the range of ~50g/m2. In this case, the solid content concentration of the coating liquid is generally about 40 to 75% by weight, but in consideration of operability, it is preferably in the range of 45 to 70% by weight.

[0016] Also, the coating composition for the cast coating layer contains a pigment and an adhesive, or an adhesive as main components, similar to the conventional composition for cast coating paper. That is, examples of pigments include clay, kaolin, aluminum hydroxide, calcium carbonate, titanium dioxide, barium sulfate,
One or more types of pigments commonly used for coated paper, such as zinc oxide, satin white, and plastic pigments, are appropriately selected and used.

Examples of adhesives include proteins such as casein, soybean protein, and synthetic proteins, conjugated diene polymer latex such as styrene-butadiene copolymer, and polymers or copolymers of acrylic esters and/or methacrylic esters. Acrylic copolymer latex such as polymer, ethylene, etc.
Vinyl copolymer latex such as vinyl acetate copolymer, or alkali-soluble or alkali-insoluble polymer latex modified with a monomer containing a functional group such as a carboxyl group, polyvinyl alcohol, One or more of the usual adhesives for coated paper, such as synthetic resin adhesives such as olefin/maleic anhydride resin and melamine resin, starches such as positive starch and oxidized starch, and cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose. are selected and used as appropriate.

Furthermore, various auxiliary agents such as an antifoaming agent, a coloring agent, a mold release agent, and a fluidity modifier are appropriately blended into the coating composition as required. The cast coating solution thus obtained is coated onto a support to a dry weight of 1 to 30 g/m@2 and finished by casting to obtain a patterned cast paper.

[0019]

[Examples] The present invention will be explained in more detail with reference to Examples below, but the present invention is of course not limited to these. Further, "parts" in the examples indicate "parts by weight" unless otherwise specified.

Example 1 100 parts of heavy calcium carbonate, 7.5 parts of styrene-butadiene copolymer latex (solid content), oxidized starch (
A coating liquid having a solid content concentration of 61% was prepared, consisting of 1 part (solid content). This coating liquid was coated on one side of a base paper with a basis weight of 70 g/m2 using an air knife coater so that the dry weight was 15 g/m2, and then dried using an air floating dryer and a cylinder dryer. Next, between the nip consisting of the embossing roll and the opposing roll, the coated layer side is in contact with the opposing roll, and the gloss level (Lg) of the low gloss area is 5%, and the gloss level (Hg) of the high gloss area is 5%. Support for cast coated paper by passing the paper under conditions such that the
I got an A.

Separately, 60 parts of kaolin, 40 parts of light calcium carbonate, 40 parts of an aqueous casein solution (solid content) dissolved using ammonia as an adhesive, and acrylic acid/butadiene/methyl methacrylate (ratio 2/33/65) A cast coating liquid having a solid content concentration of 45% was prepared, consisting of 56 parts (solid content) of polymerized latex, 1 part of tributyl phosphate as an antifoaming agent, and 3 parts of ammonium stearate as a mold release agent.

[0022] Using this cast coating liquid, wet cast finishing was carried out using the apparatus shown in Fig. 1. That is, the cast coating liquid was coated on the surface of the coating layer with a difference in gloss level of the support-A (1) using the coating device (2) so that the dry weight was 15 g/m2, A press roll (3) with a diameter of 200 mm has a diameter of 3600 mm and a surface temperature of 7.
It was pressed against a cast drum (4) at 0°C, and after drying, it was peeled off to obtain a patterned cast coated paper (5). The cast coating conditions at this time are shown in Table 1, and the quality of the patterned cast coated paper obtained is shown in Table 2.

Examples 2 to 3, Comparative Example 1 The undercoat coating solution prepared in Example 1 was applied to
The base paper was coated on one side with an air knife coater to a dry weight of 15 g/m2, and dried with an air floating dryer and a cylinder dryer. Then,
The coating layer side is in contact with the opposing roll between the nip consisting of the embossing roll and the opposing roll, and the gloss of the low gloss area and the high gloss area is 10% and 20%, respectively.
% (Support-B/Example 2), 15% and 20% (Support-C/Example 3), and 5% and 30% (Support-D/Comparative Example 1). Cast coated paper supports-B, C, and D were obtained.

Next, Example 1 was carried out, except that these three types of supports were respectively used as supports for cast coated paper.
A patterned cast coated paper was obtained using the wet casting method in the same manner as above. Table 1 shows the cast coating conditions at this time.
Furthermore, the quality of the patterned cast coated paper obtained is shown in Table 2.

Example 4 100 parts of vinylidene chloride acrylic emulsion (trade name: DX305/manufactured by Toagosei Chemical Co., Ltd.) as an adhesive;
A cast coating liquid containing 5 parts of ammonium oleate as a mold release agent and having a solid content concentration of 30% was prepared. Using this cast coating liquid, on the support A obtained in Example 1,
Coating and wet casting were performed so that the dry weight was 5 g/m 2 to obtain patterned cast coated paper. The cast coating conditions at this time are shown in Table 1, and the quality of the patterned cast coated paper obtained is shown in Table 2.

Comparative Examples 2 and 3 The undercoat coating liquid prepared in Example 1 was applied at 100 g/m2.
One side of the base paper was coated with an air knife coater to a dry weight of 15 g/m2, and dried with an air floating dryer and a cylinder dryer. Then,
A molded support-E having an unevenness of 3 μm on the surface of the support by passing the paper through a nip consisting of an embossing roll and an opposing roll so that the coated layer side is in contact with the embossing roll.
, and a molded support-F having irregularities of 20 μm was obtained.

A patterned cast coated paper was obtained by the wet casting method in the same manner as in Example 1 except that Support-E and Support-F were used. The cast coating conditions are shown in Table 1, and the quality of the patterned cast coated paper obtained is shown in Table 2.

Example 5 Solid consisting of 60 parts of kaolin, 20 parts of heavy calcium carbonate, 20 parts of light calcium carbonate, 16.5 parts of styrene-butadiene copolymer latex (solid content), and 1 part of oxidized starch (solid content). A coating liquid having a concentration of 61% was prepared. This coating liquid was coated on one side of a support having a basis weight of 100 g/m 2 using a blade coater so that the dry weight was 20 g/m 2 and was dried using an air floating dryer and a cylinder dryer. Next, the paper is passed through a super calender, and then passed through a hard roll that has been partially roughened, so that the gloss in the low gloss area is 60% and the gloss in the high gloss area is 70%. Support for cast coated paper-G
I got it. A patterned cast coated paper was obtained in the same manner as in Example 1 except that Support-G was used. The cast coating conditions are shown in Table 1, and the quality of the patterned cast coated paper obtained is shown in Table 2.

Example 6, Comparative Example 4 The undercoat paint prepared in Example 5 was applied at a weight of 100 g/m2.
One side of the base paper was coated with a blade coater to a dry weight of 20 g/m2, and dried with an air floating dryer and a cylinder dryer. Then,
The paper is passed through a super calender, and then passed through a partially roughened hard roll, resulting in an Lg of 33% and a Hg of 5.
7% cast coated paper support-H and 75% Lg
, a cast-coated paper support-I having a Hg content of 80% was obtained.

A patterned cast coated paper was obtained by the wet casting method in the same manner as in Example 1 except that Support-H and Support-I were used. The cast coating conditions at this time are shown in Table 1, and the quality of the patterned cast coated paper obtained is shown in Table 2.

Example 7 70 parts of kaolin, 30 parts of light calcium carbonate, and 0.5 parts of sodium polyacrylate as a dispersant were dispersed in water using a Coles disperser to prepare a pigment slurry with a solid content concentration of 60%. did. To this was added 0.5 parts of tributyl phosphate as an antifoaming agent, 1 part of ammonium stearate as a mold release agent, 25 parts of an aqueous casein solution (solid content) dissolved in ammonia as an adhesive, and acrylic acid/butadiene/methyl methacrylate. (ratio 2/33/65) 45 parts (solid content) of copolymer latex was added, and ZnSO
4 Add 3 parts of aqueous solution (solid content) and water until the solid content concentration is 4
A 0% cast coating solution was prepared.

Using the coating liquid thus obtained, a rewet cast finish was carried out using the apparatus shown in FIG. That is, the dry weight was 10 g/m2 using the coating device (7) on the surface of the cast coated paper support-G (6) used in Example 5.
A coating liquid was applied so that the coating liquid was applied and dried using an air floating dryer (8). Then the diameter is 1500m
The paper passes through a press nip (11) formed by a cast drum (10) of 0.5 mm, where a rewetting liquid (0.5
After rewetting the surface of the coating layer with 10%), it was pressed against a cast drum (10) whose surface temperature was 95°C, and after drying, it was peeled off to obtain a patterned cast coated paper (14). The cast coating conditions at this time are shown in Table 1, and the quality of the patterned cast coated paper obtained is shown in Table 2.

Example 8 Example 7 except that the cast coating amount was 17 g/m2.
In the same manner as above, patterned cast coated paper was obtained using the rewet casting method. The cast coating conditions at this time are shown in Table 1, and the quality of the patterned cast coated paper obtained is shown in Table 2.

Comparative Example 5 Example 7 except that the cast coating amount was 21 g/m2.
In the same manner as above, patterned cast coated paper was obtained using the rewet casting method. The cast coating conditions at this time are shown in Table 1, and the quality of the patterned cast coated paper obtained is shown in Table 2.

Example 9 70 parts of kaolin, 20 parts of light calcium carbonate, 10 parts of calcium hydroxide, and sodium polyacrylate as a dispersant.
0.5 parts and 0.5 parts of sodium pyrophosphate were dispersed in water using a Coles disperser to prepare a pigment slurry with a solid content concentration of 60%. To this, 0.5 parts of tributyl phosphate as an antifoaming agent, 1 part of ammonium stearate as a mold release agent, 25 parts of an aqueous casein solution (solid content) dissolved in ammonia as an adhesive, acrylic acid/butadiene/methyl methacrylate (Ratio 2/33/6
5) Add 45 parts of copolymer latex (solid content) and further add Z
A cast coating liquid having a solid content concentration of 40% was prepared by adding 3 parts of nSO4 aqueous solution (solid content) and water.

Using the coating liquid thus obtained, gel cast finishing was carried out using the apparatus shown in FIG. That is, the dry weight was 10 g/m2 using the coating device (16) on the surface of the cast coated paper support-A (15) used in Example 1.
A coating solution was applied so that the coating layer was gelled by contacting with an aqueous solution (17) consisting of 0.5% calcium formate and 0.5% ammonium stearate. Next, a press roll (18) with a diameter of 800 mm was used to roll the roll to a diameter of 3000 mm and a surface temperature of 80°C.
The paper was pressed onto a cast drum (19), dried, and then peeled off to obtain a patterned cast coated paper (21). The cast coating conditions at this time are shown in Table 1, and the quality of the patterned cast coated paper obtained is shown in Table 2.

Example 10 A patterned cast coated paper was produced by the gelling cast method in the same manner as in Example 9, except that the cast coated paper support-B used in Example 2 was used as the support. I got it. The cast coating conditions are shown in Table 1, and the quality of the patterned cast coated paper obtained is shown in Table 2.

[Quality evaluation method] Continuous productivity: ◎; Continuous production possible without drum picks ○; Continuous production possible although some drum picks occur ×; Continuous production impossible due to frequent drum picks Glossiness: JIS Measured according to P8142 method (%). Smoothness: Visually evaluated. ○: Excellent, △: Slightly inferior, ×: Poor Pattern clarity: Visually evaluated ◎: Very clear, ○: Clear, △: Slightly unclear

[
0039

[Table 1]

[0040]

[Table 2]

[0041]

[Effects of the Invention] As is clear from the results of the Examples, the present invention made it possible to obtain patterned cast-coated paper of extremely excellent quality without reducing continuous productivity.

[Brief explanation of the drawing]

FIG. 1 is a schematic process diagram of a wet casting method for obtaining patterned cast coated paper of the present invention.

FIG. 2 is a schematic process diagram of a rewet casting method for obtaining the patterned cast coated paper of the present invention.

FIG. 3 is a schematic process diagram of the gel casting method for obtaining the patterned cast coated paper of the present invention.

[Explanation of symbols]

(1), (6), (15): Patterned support (2), (
7), (16): Coating device (3), (9), (18): Press roll (4), (1
0), (19): Cast drum (5), (14), (
21): Patterned cast coated paper (8): Air floating dryer (11): Press nip (12): Rewetting liquid supply nozzle (17): Gelling liquid

Claims (1)

[Claims] [Claim 1] A pigment and an adhesive, or a cast coating layer mainly composed of an adhesive is formed on a support, and while the coating layer is in a wet state, the coating layer is pressed against the surface of a heated drum having a specular gloss. In a patterned cast coated paper that has been dried and finished, the support has a high gloss area and a low gloss area on its surface, and the high gloss area when each gloss area is measured by a method according to JIS P8142. A patterned cast-coated paper characterized by using a support in which the relationship between the glossiness (Hg) of the area and the glossiness (Lg) of the low-gloss area satisfies the following formula [1]. 0.2≦Lg÷Hg≦0.9 [1] [Claim 2
] The ratio of the pigment solid content to the total solid content of the cast coating layer is p, and the coating amount of the cast coating layer is w (g/m2).
, when the gloss of the high-gloss part on the surface of the support is Hg and the gloss of the low-gloss part is Lg, the relationship between these is as follows [2]
The patterned cast coated paper according to claim 1, which satisfies the formula: 0≦p×w×Lg÷Hg≦10 [2] [Claim 3] The ratio of the pigment solid content to the total solid content of the cast coating layer is p, and the coating amount of the cast coating layer is w (g/m2
), the gloss of the high-gloss area on the support surface is Hg, and the gloss of the low-gloss area is Lg, and the relationship between these is as follows [3
The patterned cast coated paper according to claim 1 or claim 2, which satisfies the following formula. 0≦p×w×Lg÷Hg≦8 [3]