JP2684881B2 - Manufacturing method of coated paper for aluminum foil bonding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a coated paper for laminating aluminum foil, which comprises laminating an aluminum foil on one surface of a coated paper for printing to obtain an aluminum foil-coated coated paper.

[0002]

2. Description of the Related Art A conventional coating solution for printing coated paper is applied to one side (A side) of a base paper, and an aluminum foil is attached to the opposite side of the base paper (B side). Aluminum foil laminated coated paper is printed on the coated side of the coating liquid, and then the aluminum foil side is normally placed inside to make a box to make a container that does not leak water or oil from food. Used. It is also used for creating catalogs and pamphlets using the gloss of aluminum foil. Further, it has been proposed to use a coated paper having an aluminum foil stuck thereon as a base material for a lithographic printing original plate (Japanese Patent Laid-Open No. 58-17449).

Generally, when a metal foil of aluminum, zinc, copper or the like is attached to paper, that is, when so-called laminating is performed, as an adhesive for adhering the two, a vinyl acetate resin, an acrylic resin, a polyolefin resin, Each resin such as a urethane resin and a phenol resin is used alone, in a mixed state or in a copolymerized state depending on its use. These are applied as a water-based paint in the form of an emulsion or as a solvent-based paint by selecting an appropriate solvent between the layers of the metal foil and the paper for lamination. In addition, water-soluble resins such as casein, poval, and starch may be used as the adhesive. In addition, as a laminating method, a hot-melt method or an extrusion coating method using a resin such as wax-based resin, polyolefin-based resin (polyethylene, polypropylene, ethylene-vinyl acetate copolymer resin, ionomer, etc.) that melts by heating, etc. Is also well used. Of these, water-based adhesives are usually preferred because they are easy to work with and are non-polluting.

[0004]

By the way, the surface of the base paper on which the aluminum foil is laminated is used as smooth as possible. However, since the base paper originally has the entanglement of cellulose fibers and uneven texture, etc. Due to this, there are various irregularities of various sizes, and there is a drawback that these irregularities appear as they are on the laminated aluminum foil. This has led to a significant reduction in the surface homogeneity, flatness and gloss of the aluminum foil, which has led to a drop in commercial value.

Further, when a water-based adhesive is used for laminating aluminum foil, there is a problem that the base paper swells due to water permeating from the surface of the base paper, which promotes unevenness of the base paper.

Furthermore, if the smoothness of the base paper surface is poor, even if a certain amount of adhesive is used, the covering properties of the adhesive will not be sufficient, so that the adhesive strength will be weakened or the desired adhesive strength will be obtained. The drawback is that a large amount of adhesive is required.

In order to prevent this, there is a method of using a normal coated paper for double-sided printing in which the same amount of the same coating liquid is applied on both sides of the base paper, but printing is performed between the aluminum foil and the base paper. Even if a coating layer for coating is provided, this layer does not print, so there is no meaning, and the cost is high, which is not desirable.

The aluminum foil to be laminated is usually 5 to 2 thick.
Those of 0 μm are preferably used. If this thickness is increased, the unevenness due to the base paper is less likely to appear on the aluminum surface, but this method also causes a high cost.

Therefore, the present invention is a so-called aluminum foil laminating coated paper in which a printing coating layer is provided on one side (A side) of the base paper and an aluminum foil is laminated on the opposite side (B side). The present invention provides a method for producing a coated paper for aluminum foil bonding, which can maintain the original surface flatness and glossiness of the aluminum foil without causing irregularities of various sizes on the surface of the aluminum foil after bonding. It was made for the purpose.

[0010]

Means for Solving the Problems As a result of intensive studies aimed at eliminating the above-mentioned drawbacks of the prior art, the inventors of the present invention have a pigment and an adhesive as the main components on the base paper surface (B surface) to which the aluminum foil is attached. By coating the aqueous coating solution with a certain range of coating amount and then applying a surface sizing agent with a certain range of coating amount, the aluminum foil surface flatness after bonding can be made extremely high. They have found that an excellent coated paper for laminating aluminum foil can be obtained, and completed the present invention.

That is, in the method for producing a coated paper for laminating aluminum foil according to the present invention, one side (A side) of a base paper is coated with an aqueous coating liquid A containing a pigment and an adhesive as main components, and the A side is coated. The reverse base paper surface (B surface) is coated with (1) an aqueous coating liquid B containing a pigment and an adhesive as a main component in an absolute dry weight of 1 to 10 g / m ² , and further thereon (2) surface size. 0.5 to 0.5 in dry weight
It is characterized by coating at 5 g / m ² . An aluminum foil-bonded coated paper can be obtained by bonding an aluminum foil on the surface sizing agent-coated surface on the B side of this coated paper.

Further, in a preferred embodiment of the present invention, the degree of Cobb size of the surface coated with the surface sizing agent (JIS
P8140) is 30 g / m ² or less.

In the present invention, the pigments of the aqueous coating liquid A for coating the side A of the base paper and the aqueous coating liquid B for coating the side B of the base paper include kaolin, clay, calcium carbonate, titanium oxide, aluminum hydroxide, It can be appropriately selected and used from zinc oxide, barium sulfate, calcium sulfate, talc, silica, plastic pigment, satin white and the like.

As the adhesive, modified starch such as casein, soybean protein, yeast protein, starch, oxidized starch and esterified starch, etherified starch, cationized starch and enzyme modified starch,
Natural adhesives such as cellulose derivatives and styrene
Butadiene-based copolymers, conjugated diene-based polymer latexes such as methylmethacrylate / butadiene-based copolymers, acrylic-based polymer latexes such as acrylic acid ester / methacrylic acid ester polymers or copolymers, ethylene / vinyl acetate copolymers One or more appropriately selected from vinyl acetate polymer latex such as polymer and synthetic adhesive such as polyvinyl alcohol can be used.

The amount of the adhesive used is 8 to 30 parts by weight, preferably 10 to 20 parts by weight, based on 100 parts by weight of the pigment. When the amount of the adhesive used is 8 parts by weight or less, the strength of the coated surface becomes weak, and when it is 30 parts by weight or more, the cost increases.

In the preparation of the aqueous coating liquid, various kinds of ordinary coating liquids for coated paper such as a dispersant, a flow modifier, a water resistance agent, a printability improver, a defoaming agent and a colorant are added. The auxiliary agent can be appropriately selected and used as necessary in order to obtain desired properties.

The aqueous coating liquid A and the aqueous coating liquid B may have the same composition or different compositions. The coating surface of the coating liquid A (side A) is the surface to be printed, whereas the coating surface of the coating liquid B (side B) is the surface on which the surface sizing agent is applied. Therefore, it is not always necessary to make the composition in consideration of printability. It is also preferable to add a waterproofing agent to the coating liquid B.

The thus-prepared aqueous coating liquid A was made by a conventional paper machine using a pulp selected from bleached softwood kraft pulp, bleached hardwood kraft pulp, recycled pulp from recycled paper, and mechanical pulp. One side (A side) of the acid base paper or the neutral base paper is coated with 10 to 30 g / m ² , more preferably 15 to 25 g / m ² . An undercoat coating of about 3 to 15 g / m ² may be applied prior to coating the coating liquid A on the surface A.

On the other hand, on the side B opposite to the side A of the base paper, the aqueous coating liquid B prepared in the same manner as the aqueous coating liquid A is added.
10 g / m ^2, desirably 2-5 g / m ² coating.
When the coating amount of the coating liquid B is less than 1 g / m ² , the unevenness of the base paper is not sufficiently covered, and the aluminum foil surface flatness tends to be insufficient after laminating the aluminum foil. Conversely, the coating amount of coating liquid B is 1
Exceeding 0 g / m ² leads to high cost.

Either coating of the aqueous coating liquid A on the side of the base paper A or coating of the aqueous coating liquid B on the side of the base paper B may be performed first.

The base paper used in the present invention has a basis weight of 50 to 400.
It is possible to use g / m ² and it is possible to use a single-layer papermaking or a multi-layer papermaking, but it is properly used depending on the application. That is, it is said that the base paper having a basis weight of about 80 to 150 g / m ² is used for a sheet-shaped sheet such as a catalog or a pamphlet, and the grammage of about 200 to 300 g / m ² is used for a box-making product. .

The surface sizing agent applied on the surface of the base paper B coated with the aqueous coating liquid B may have the same composition as the surface size press applied when the base paper is made into a paper, and the desired lump size It may be changed appropriately to obtain the desired degree, and a water resistant agent may be added. It is also possible to use a pigment such as clay or calcium carbonate in combination.

The purpose of the surface sizing agent is, as is well known, a mechanism of allowing the components of the surface size to permeate from the surface of the base paper to fill the gaps, and also to form a film by using a polymer substance such as a synthetic product. Be expected.

The surface sizing agent applied when making a base paper is usually a relatively small coating amount of 0.01 to ² g / m ^{2 on} one side in absolute dry weight, but in the present invention, it is applied to the B side of the base paper. The surface sizing agent is 0.5-5 g / m ² in terms of absolute dry weight
Desirably, the desired effect is obtained at 1.5 to 3 g / m ² . When the coating amount of the surface sizing agent is less than 0.5 g / m ^{2, the} flatness of the surface of the aluminum surface after laminating the aluminum foil is poor and the desired degree of bump size cannot be obtained. 5 g / m ²
When it is more than that, the load of the dryer becomes large and the production speed is lowered, which is a drawback.

As the surface sizing agent, starch, modified starch, starch derivative, cellulose derivative, casein, polyvinyl alcohol, polyvinyl acetate, synthetic rubber emulsion, styrene / maleic acid copolymer, vinyl acetate / maleic acid copolymer, poly One or more kinds may be appropriately selected from acrylamide, amine-based polymer, styrene / acrylic copolymer, olefin / maleic acid copolymer, alkylketene dimer, urea resin, colloidal silica and the like.

The coating and drying method employed in the present invention is not particularly limited, and may be a blade coater, an air knife coater, a bar coater, a roll coater, a chanplex coater or the like used in the production of general coated paper. It is coated in a single layer or multiple layers, dried to a paper moisture of about 3-8%, and wound on a reel. Alternatively, one coater having two or more coating equipments may continuously coat the side A and the side B of the base paper,
Alternatively, it is possible to coat either the A side or the B side, then dry and wind once, and then coat the remaining other side. The aqueous coating liquid B to be coated on the B side of the base paper and the surface sizing agent to be coated thereon may be coated by different coaters, or may be continuously coated by one coater. .

[0027]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples. In addition, all parts or% shown in Examples and Comparative Examples represent absolute dry weight parts or absolute dry weight%. In addition, all coating amounts are displayed in absolute dry weight.

Example 1 40 parts of kaolin (trade name: Ultra White 90 manufactured by Engelhard Minerals and Chemicals (EMC), USA, trade name, Ultra White 90) as a pigment and heavy calcium carbonate having a particle diameter of 1 to 4 μm (made by itself, ground calcium carbonate) ) 60 parts were put into a mixer, and while being stirred, oxidized starch (Oji Constarch Co., Ltd., trade name Oji Ace A 10% solution) 3
Part and latex 50% liquid (Asahi Kasei Co., Ltd., trade name L-
1537) 12 parts, and then 0.3% of sodium polyacrylate as a dispersant per pigment, 0.5% of calcium stearate as a lubricant, and 0.2% of fluorescent dye are sequentially added, and after sufficiently mixing and dispersing, 25% ammonia is added. P using an aqueous solution
Aqueous coating liquid A (solid content concentration 6
0%).

This coating liquid A was made with a known paper machine using bleached hardwood kraft pulp to obtain a single layer paper having a basis weight of 80 g /
20 g / m ^{2 was} coated on one side (A side) of the m ² base paper with a blade coater (manufactured by Mitsubishi Heavy Industries, Ltd.) and dried by a known dryer to produce a one-side coated paper having a paper moisture content of 6%.

Then, on the side B of the above-mentioned one-side coated paper, which is the side opposite to the coated side A, the aqueous coating liquid B prepared as described below was prepared in the same manner as the aqueous coating liquid A.3. After coating with 0 g / m ^2, it was wound up.

(Aqueous Coating Solution B) Kaolin (Ultra White 90) 30 parts Heavy calcium carbonate (manufactured, particle size 1 to 4 μm) 70 parts Oxidized starch (Oji Ace 10% liquid) 2 parts Latex (L-1537) ) 50% liquid 14 parts As in the case of the aqueous coating liquid A, 0.3% of sodium polyacrylate as a dispersant per pigment, 0.5% of calcium stearate as a lubricant, and 0.2% of fluorescent paint are sequentially added to the above components. After adding and thoroughly mixing and dispersing, the pH was adjusted to alkali with a 25% aqueous ammonia solution. Solids concentration is 6
0%.

Next, a surface sizing agent solution was further coated on the surface coated with the coating solution B with a roll coater (manufactured by Mitsubishi Heavy Industries, Ltd.) at 2.5 g / m ² and then dried to obtain a paper moisture content of 6 ．
A 5% double-sided coated paper was obtained. The surface sizing agent liquid used at this time had the following composition.

Oxidized starch (Oji Ace A) 10% solution 6.0 parts Polyvinyl alcohol (Kuraray Co., Ltd., trade name PVA105) 10% solution 1.5 parts Water 25 parts

The obtained double-sided coated paper was supercalendered at a nip pressure of 250 kg / cm to obtain an aluminum foil-coated coated paper of the present invention. The surface sizing agent-coated surface (B side) of this coated paper had a degree of Cobb size of 23 g / m ² .

Next, using an aluminum foil laminating machine, 2 g / m ^{2 of} vinyl acetate emulsion was applied to the surface sizing agent coated surface (B side) of this coated paper, and aluminum foil having a thickness of 7 μm was further laminated. Then, an aluminum foil-bonded coated paper was obtained. Table 1 shows the results of evaluation of the quality of the aluminum foil-bonded coated paper.

The quality evaluation method at this time is as follows. 1) Cobb size degree: JIS P8140 was applied. However, the time from the addition of water to the removal of water was 30 seconds.

2) Aluminum foil surface flatness: The surface of the aluminum foil was visually observed and the presence or absence of irregularities was expressed as follows. Smooth appearance without any irregularities ○ Rough appearance with many irregularities ×

3) Adhesive strength of aluminum foil: After the aluminum foil was bonded, the aluminum foil was peeled off from the edge of the paper with a nail, and the adhesiveness between the coated paper and the aluminum foil was evaluated by observing the state. Excellent adhesiveness ○ (Aluminum foil will tear if you try to peel it off forcibly) Poor adhesiveness × (Aluminum foil will peel off from the coated paper without tearing)

Example 2 A coated paper for laminating aluminum foil was produced in exactly the same manner as in Example 1 except that the surface sizing agent solution was coated with a blade coater in the following composition at 1.5 g / m ^2. Quality evaluated. Table 1 shows the results. Oxidized starch (Oji Ace A) 10% solution 6.0 parts Polyvinyl alcohol (PVA105) 10% solution 2.0 parts Styrene / acrylic resin (Arakawa Chemical Co., Ltd. trade name Polymaron 1301) 15% solution 2.0 parts Water 30 Department

Example 3 A coated paper for laminating aluminum foil was produced and quality evaluated in exactly the same manner as in Example 1 except that the surface sizing liquid had the following composition. Table 1 shows the results. Enzyme-modified starch (made in-house) 10% solution 6.0 parts Water 25 parts

Example 4 A coated paper for laminating aluminum foil was produced and quality evaluated in exactly the same manner as in Example 1 except that the surface sizing liquid had the following composition. Table 1 shows the results. Oxidized starch (Oji Ace A) 10% solution 7.5 parts Modified polyamide resin (trade name Epinox P9007Y manufactured by Dick Hercules) 30% solution 0.3 parts Water 24 parts

Example 5 A coated paper for laminating aluminum foil was produced and quality evaluated in exactly the same manner as in Example 1 except that 3 g / m ^{2 of the} surface sizing liquid was applied as the following composition. Table 1 shows the results. Oxidized starch (Oji Ace A) 10% solution 7.0 parts Kaolin (Ultra White 90) 60% dispersion 2.0 parts Water 25 parts

Example 6 In Example 1, first, the aqueous coating solution B and the surface sizing agent solution were sequentially coated on one side (side B) of the base paper, and thereafter, the aqueous coating solution was coated on the opposite side (side A). Except that A was coated, the coated paper for laminating aluminum foil was manufactured and the quality was evaluated in exactly the same manner as in Example 1. Table 1 shows the results.

Example 7 In Example 1, the middle layer of the base paper had a basis weight of 10 g / m ² ,
An aluminum foil was prepared in exactly the same manner as in Example 1 except that a base paper having a basis weight of 120 g / m ² was made on both sides of the middle layer to form a three-layer base paper having a total basis weight of 250 g / m ^2. A coated paper for laminating was manufactured and its quality was evaluated. Table 1 shows the results.

Example 8 Using the base paper of Example 7, Example 1 is applied to this one side (A side).
The coating liquid B used in Example ^{2 was} applied as an undercoat of 10 g / m ² , and the coating liquid A used in Example 1 was further applied as an overcoat of 15 g / m ² thereon. Next, the base paper surface (B
Coating solution B used in Example 1 on the surface) at 4 g / m ² and
On top of that, the surface sizing agent liquid used in Example 1 was added.
5 g / m ^{2 was} applied. Otherwise, the coated paper for laminating aluminum foil was manufactured in exactly the same manner as in Example 1, and the quality was evaluated. Table 1 shows the results.

Example 9 In Example 8, 1 part of a 30% solution of modified polyamide resin (Epinox P9007Y) was further added to coating liquid B and mixed well, and then the same coating as in Example 8 was performed. A coated paper for laminating was manufactured and its quality was evaluated. Table 1 shows the results.

Comparative Example 1 Except that the surface sizing agent solution was not applied to the B side of the base paper,
Exactly the same as in Example 1, a coated paper for laminating aluminum foil was manufactured and the quality was evaluated. The results are also shown in Table 1.

Comparative Example 2 Except that the surface sizing agent liquid was not applied to the B side of the base paper,
The coated paper for laminating aluminum foil was manufactured and quality evaluated in exactly the same manner as in Example 8. The results are also shown in Table 1.

As can be seen from Table 1, the aluminum foil-bonded coated paper produced from the aluminum foil-bonded coated paper obtained by the method of the present invention has an extremely flat appearance without fine irregularities on the aluminum foil surface. Also, the adhesiveness between the aluminum foil and the coated paper is extremely excellent.

[0050]

As described above, according to the present invention, an aluminum foil is laminated which has an excellent surface flatness of aluminum foil after laminating the aluminum foil and a good adhesiveness between the coated paper and the aluminum foil. The combined coated paper can be obtained, and the contribution to the industry is extremely large.

[0051]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Kajita 373 Yoshioka, Yonago, Tottori Prefecture Oji Paper Co., Ltd. Yonago Mill (72) Inventor, Kusumi 373 Yoshioka, Yonago, Tottori Yonago Paper Co., Ltd. in the factory

Claims (2)

(57) [Claims] 1. An aqueous coating solution A containing a pigment and an adhesive as a main component is applied to one side (A side) of the base paper, and (1) pigment and adhesive are applied to the base paper side (B side) opposite to the A side. Aqueous coating liquid B containing the agent as a main component is applied at an absolute dry weight of 1 to 10 g / m ² , and (2) a surface sizing agent is applied at an absolute dry weight of 0.5 to 5 g.
/ M ² coating, a method for producing a coated paper for laminating aluminum foil for laminating an aluminum foil on the B side. 2. The method for producing coated paper for laminating aluminum foil according to claim 1, wherein the degree of Cobb sizing of the surface of the surface B after the surface sizing agent is coated is 30 g / m ² or less.