JPH08144192A - Moisture-proof paper - Google Patents

Abstract

(57) [Summary] [Structure] In packaging of OA equipment and its consumables, styrene monomer and butadiene monomer, which are hydrophobic unsaturated monomers, are added to the surface of the base paper in an amount of 25 to 35% by weight and a hydrophilic simple substance. 35 to 50% by weight of methyl methacrylate, which is a monomer, and 20 to 30 of ethyl acrylate and methacrylic acid.
5% by weight of stearic acid ester to 100 parts by weight of the solid content of the emulsion-copolymerized aqueous emulsion.
Moisture-proof paper obtained by applying and drying a coating solution prepared by mixing and adding 20 to 20 parts by weight (solid content). [Effects] This moisture-proof paper has the same moisture resistance as conventional moisture-proof paper coated with a synthetic resin such as polyethylene, and the disaggregation of fibers during recycled paper is similar to that of unprocessed paper. It can be used without problems as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-proof paper used in a moisture-proof packaging in which paper is coated with a synthetic resin in packaging of OA equipment and its consumables.

[0002]

2. Description of the Related Art A wax emulsion is applied to obtain a moisture-proof paper that can be recycled as waste paper (Japanese Patent Publication No.
3-39022, Japanese Patent Publication No. 63-39023, etc.), a mixture of wax emulsion and synthetic rubber emulsion (Japanese Patent Publication No. 55-22597), or a mixture of wax emulsion and water-soluble emulsion. (Japanese Patent Laid-Open No. 3-279492) has been proposed. Further, as an example of coating a resin which is only soluble in an alkaline aqueous solution and insoluble in water, a photosensitive resin which is provided with such a characteristic at the time of producing a printing plate is disclosed (Japanese Patent Laid-Open No. 1-179934 and Japanese Patent Laid-Open No. 2-14604).
No. 2, etc.), but the present invention is completely different in use and purpose. Further, a material close to the present invention is found in pigment-coated paper (Japanese Patent Publication No. 54-15924), but this resin alone has no effect, and is further coated with an aqueous metal salt solution.

Conventionally, moisture-proof processing of paper has been carried out by laminating a synthetic resin film using a synthetic resin such as polyethylene as an adhesive or by directly coating a molten resin on the paper. However, when the used paper is collected and recycled, the adhesiveness between the paper and the synthetic resin film is strong, so that the disintegration efficiency in the disintegration process in the used paper plant is significantly reduced, and There have been problems that the fibers of the paper are difficult to separate from the resin remaining as the dissociated resin, the yield of the fibers is reduced, or the resin portion is difficult to be removed in the step of removing unnecessary substances.

Therefore, in order to obtain a moisture-proof paper that can be recycled as waste paper, a wax emulsion is applied (Japanese Patent Publication No. Sho 63-39022, Japanese Patent Publication No. Sho 63-39023, etc.), a wax emulsion and a synthetic rubber emulsion. There is a method in which the wax is mixed and coated (Japanese Patent Publication No. 55-22597) or a method in which the wax-based emulsion and the water-soluble emulsion are mixed and coated (Japanese Patent Laid-Open No. 3-279492), but none of them has a large wax content. Since the moisture-proof property is low, there are drawbacks such that the processed paper is slippery and causes mechanical damage or blocking. Even if they can be disintegrated, it is difficult to completely remove the resin, and the resin will re-float when paper is made after recycling, and in the case of a white product, only the appearance when using recycled copy paper or printing paper. Instead, problems occur with copy quality and print quality.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has moisture resistance and usability equivalent to those of conventional moisture-proof paper coated with a synthetic resin such as polyethylene, and recycled recycled paper. The purpose of the present invention is to obtain a moisture-proof paper in which the yield of fibers at the time is equivalent to that of unprocessed paper, and the recycled pulp can be used without problems like newspaper waste paper.

[0006]

According to the present invention, in packaging of OA equipment and its consumables, 25 to 35 parts by weight of styrene monomer and butadiene monomer, which are hydrophobic unsaturated monomers, are provided on the surface of the base paper. %, 35 to 50% by weight of methyl methacrylate as a hydrophilic monomer, and 20 to 30% by weight of ethyl acrylate and methacrylic acid, relative to 100 parts by weight of solid content of the emulsion-copolymerized aqueous emulsion. There is provided a moisture-proof paper characterized by being obtained by applying a coating solution obtained by mixing and adding 5 to 20 parts by weight (solid content) of stearic acid ester and drying.

Further, according to the present invention, as a preferred embodiment, there is provided a moisture-proof paper in which the base paper is white paper such as bleached kraft paper and white fine paper. Further, there is also provided a moisture-proof paper characterized in that the resin solid content of the coating liquid is held between two sheets of paper.

The moisture-proof paper is desired to exhibit the following functions. That is, when used as a moistureproof material, moisture is blocked by the synthetic resin coated on the base paper. On the other hand, when used paper is discarded, collected and recycled after used, the synthetic resin is dissolved (or finely dispersed) in the alkaline raw material liquid in the disintegrator and separated from the base paper. As a result, the base paper is efficiently disintegrated. The synthetic resin component is then washed away and does not appear in the paper made as recycled paper. In addition, if the base paper is white paper such as bleached kraft paper or white high-quality paper, not only unbleached (unbleached) paper such as corrugated cardboard and paperboard, but also cheap newspapers It can be reused as high-quality waste paper such as waste paper and recycled copy paper.

In order to perform such a function, in the present invention, the resin of the coating liquid is a carboxylated resin so that the hydrophilic resin and the hydrophobic resin are balanced and the resin is soluble in an alkaline aqueous solution. It has been modified. In addition, the contribution of stearic acid ester added afterwards to the moisture-proof performance is large,
Moisture-proof performance is secured by adding a small amount. It is considered that this is because the hydrophilic group of the stearic acid ester is drawn to the hydrophilic group of the base polymer, and the hydrophobic portion of the stearic acid ester faces the surface. Next, by holding this resin between two sheets of paper, the resin part is hidden in appearance, so that the recovery rate as used paper after use is increased, and mechanical friction etc. It is possible to prevent the resin layer from being damaged.

[0010]

EXAMPLES The present invention will be described below with reference to examples, but the embodiments of the present invention are not limited thereby.

Example 1 5% by weight of styrene 27% by weight of butadiene 27% by weight of MMA 43% by weight of EA 15% by weight of MAA 10% by weight of MAA were put into a reaction vessel equipped with a stirrer together with water and reacted at 80 ° C. for 3 hours. This is neutralized with a sodium hydroxide solution to obtain a dispersion having a pH of 6.8 to 7.2. The stearic acid ester dispersion is added to this in a weight ratio of 100: 10,
Stir. Using a blade coater, a liquid having a solid content of 47% was exposed to bleached kraft paper having a basis weight of 70 g / m ² , 14, 16, and 1.
8 g / m ² coating and drying. For the obtained sample,
The moisture permeability, the disintegration property of the paper fiber, and the presence or absence of residual resin were confirmed. For comparison, low density polyethylene laminated paper (laminate film thickness: 20 μm) was similarly tested and the results are also shown. In this case, the same kraft paper as in the example was used as the base paper.

The test method adopted is as follows. -Moisture Permeability JISZ0208 Moisture Permeability Test Method 3.3
According to temperature and humidity condition B. -Disaggregation A piece of paper was cut into 30 mm square and disaggregated at a pulp conversion concentration of 4% by a small laboratory disintegrator for 10 minutes. The paper was made by hand and visually checked for the presence of fiber lumps in the paper.
The pH of the aqueous solution is 12 to 13, and the temperature is 40 ° C. -Evaluation of residual resin The paper obtained by hand-making was left at 140 ° C for 5 hours to visually confirm the resin content.

(Results) Sample Water vapor transmission rate Degradability Residual resin Example 1 14g / m ² 45g / m ² · 24Hr ○ None 16g / m ² 38g / m ² · 24Hr ○ None 18g / m ² 30g / m ² · 24Hr ○ None Polyethylene laminated paper 35g / m ² · 24Hr × 1 to 30mm Single copy paper (comparison) − ○ None

[0014]

As described above, according to the present invention, the moisture-proof property is equivalent to that of a conventional moisture-proof paper coated with a synthetic resin such as polyethylene, and the disaggregation property of fibers at the time of recycling used paper is unprocessed paper. A moisture-proof paper can be obtained that is equivalent to, and can be used without problems, as with waste newspaper.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location C09K 3/18 101 (72) Inventor Masakazu Nakata 1-3-6 Nakamagome, Ota-ku, Tokyo Stocks In-house Ricoh Company (72) Inventor Susumu Matsuzaki 4-4 Tatsumi Taito, Ichihara-shi, Chiba Daiki Inki Ki-Tatsu Dormitory (72) Inventor Toshihiko Yoshida 500 Tsuchida, Kani-shi, Gifu Nagoya Pulp Co. Ltd.

Claims (3)

[Claims] 1. In packaging of OA equipment and its consumables, 25 to 35% by weight of styrene monomer and butadiene monomer, which are hydrophobic unsaturated monomers, on the surface of the base paper.
And methyl methacrylate, a hydrophilic monomer, in an amount of 35 to 50
20 to 3% by weight of ethyl acrylate and methacrylic acid
Obtained by coating and drying a coating solution obtained by adding 5 to 20 parts by weight (solid content) of stearic acid ester to 100 parts by weight of solid content of an emulsion-copolymerized aqueous emulsion containing 0% by weight. A moisture-proof paper which is characterized by being produced. 2. The moisture-proof paper according to claim 1, wherein the base paper is white paper such as bleached kraft paper and white wood free paper. 3. The moisture-proof paper according to claim 1, wherein the resin solid content of the coating liquid is held between two sheets of paper.