JPH0715800U - Moisture-proof and waterproof paper for easy re-disaggregation - Google Patents

Abstract

(57) [Abstract] [Purpose] Supplying recyclable moisture-proof paper that is easy to distinguish from poly-laminated paper [Structure] Coating paper with a moisture-proof agent consisting of latex and wax containing color pigments By providing the layer, the moisture-proof paper can be distinguished from the poly-laminated paper at first glance.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a moisture-proof paper having a moisture-proof and waterproof layer formed on the outer surface of the paper layer. More specifically, the present invention relates to a recyclable moisture-proof paper in which the coated surface of a moisture-proof paper that is easy to disintegrate is colored so that it can be distinguished from a moisture-proof paper that is difficult to disintegrate by laminating a polymer compound on the paper. ..

[0002]

[Prior art]

 For winding fine wood, bleached kraft paper, unbleached kraft paper and various coated papers, and for plain paper wrapping of high-quality papers and coated papers, in order to prevent moisture absorption of the product, polyolefin-based materials such as polyethylene and polypropylene are used. A wrapping paper having moisture resistance and water resistance obtained by coating, laminating or internally adding the polymer compound of is used. In addition, since heavy bags such as cement bags, salt bags, feed bags, fertilizer bags, and garbage bags require moisture resistance and strength to prevent moisture absorption and water absorption, polyolefin laminates made by laminating polyethylene, polypropylene, etc. on kraft paper. Paper (hereinafter referred to as poly-laminated paper) and kraft paper are stacked and used as a bag.

However, in these poly-laminated papers, polymer compounds are not sufficiently disaggregated in the process of reusing used papers, which is a problem in terms of recycling. In addition, when disposing of the product, the user has to bear the cost and it is difficult to dispose of it from the viewpoint of environmental pollution. As a paper that can be recycled and has sufficient moisture-proof and waterproof property, for example, Japanese Patent Publication No. 55-22587 discloses a moisture-proof and waterproof paper in which a synthetic rubber latex and a wax emulsion are applied to the paper. Further, in JP-A-56-148997, a synthetic hydrocarbon resin and wax are placed in water by using a styrene-maleic acid-based copolymer and a surfactant in the presence of at least a flash equivalent of alkali. A composition for moistureproofing paper is disclosed which comprises a mixture with an emulsion obtained by dispersion.

The moisture-proof paper obtained by these methods is characterized in that it can be easily recycled because its moisture-proof layer is easily separated and dispersed in water against mechanical disaggregation. However, since the moisture-proof paper obtained by these methods is very similar in appearance to poly-laminated paper, it requires some habituation for the user to identify, and various moisture-proof papers can be used in various environments. When used as a sheet, the difficulty of distinguishing it from poly-laminated paper becomes a problem in recycling.

[0005]

[Problems to be solved by the device]

 The present invention aims to provide recyclable moisture-proof and waterproof paper that can be distinguished from poly-laminated paper.

[0006]

[Means for Solving the Problems]

 Moisture-proof, which has latex and wax as a moisture-proof layer on the base paper, is easy to re-dissolve. Although it is easy to think of a method of coloring the engineering side, for example, when unbleached kraft paper is used, it becomes a dirty color when colored. Also, when one side of the base paper is colored, color loss on the back side often occurs. Therefore, the present inventors have devised that the moisture-proof layer can be colored to make it beautiful and easy to distinguish from poly-laminated paper. That is, it is achieved by a moisture-proof and waterproof paper which is easy to be re-disaggregated and characterized in that it has a moisture-proof layer composed of latex, wax and a coloring pigment on a base paper mainly composed of wood pulp.

The present invention will be described in detail below. The coloring pigment is not limited to natural pigments and synthetic pigments, but among the synthetic pigments, organic pigments are preferably used from the viewpoint of color development. As organic pigments, there are used copper phthalocyanine for blue and green, condensed azo for yellow, insoluble azo, insoluble azo for orange, soluble azo for red, insoluble azo, condensed azo, and dioxane for purple. These are known as colorants for papermaking and colorants for coated paper. The above color pigments are usually used as an aqueous dispersion. As the dispersant, there are a nonionic active agent and an ionic active agent, and they are appropriately selected in consideration of the compatibility of the moistureproofing agent with the coating liquid composition and the stability against water dilution.

Although the amount of the coloring pigment added varies depending on the color, it can be seen that if the amount of the coloring pigment is 0.2% by weight or more based on the solid content of the moisture-proofing agent, the coloring is sufficiently visually observed. The moisture-proofing agent described below is usually applied to the base paper in a solid content of 15 to 20 g / m ² . The base paper can be appropriately selected from high-quality paper mainly made of chemical pulp (hardwood kraft pulp, softwood kraft pulp, etc.) or mechanical pulp, medium-quality paper, single-gloss kraft paper, both-furnished kraft paper and stretched paper.

The moisture-proofing agent is not particularly limited as long as it is easy to separate and disperse in water against mechanical disaggregation when it is applied as a moisture-proofing paper, and examples thereof include styrene-butadiene-based latex and methyl methacrylate. -Synthetic rubber latex such as butadiene latex and acrylonitrile-butadiene latex, and wax emulsion such as paraffin wax emulsion or polyethylene wax emulsion are used as a mixture. The compounding ratio (solid content) of the latex and the wax is 50 to 80% by weight of the latex and 20 to 50% by weight of the wax. As a coating facility for the moisture-proof layer, an air knife coater, a bar coater, a roll coater, a blade coater or the like can be arbitrarily selected and coated.

[0010]

[Action]

 By applying a moistureproofing agent and a coloring pigment to the paper to form a moistureproof paper having a colored moistureproof surface, it can be easily distinguished from poly-laminated paper.

[0011]

【Example】

In order to make the invention easier to understand, the following examples are shown, but the following embodiments do not limit the invention. The weight% in the text means the solid content weight%. Example 1 57.5% by weight of styrene / butadiene copolymer latex polymer (polymer glass transition point: 20 ° C., manufactured by Nippon Zeon, solid content: 45%) on unbleached Ranshin kraft paper (grammage 70 g / m ² ). And wax emulsion (trademark: OKW-40, manufactured by Arakawa Chemical Co., Ltd., solid content 40%) 42% by weight, and a green pigment (copper phthalocyanine, TB-700, manufactured by Dainichiseika Kogyo Co., Ltd.) 0.5% by weight as a color pigment. The colored dehumidifying agent solution was hand-coated with a Meyer bar at 15 g / m ² and then dried at 105 ° C. for 1 minute.

Example 2 A moisture-proof paper was produced in the same manner as in Example 1 except that purple (dioxazine, TB-1500, manufactured by Dainichiseika Kogyo) was used as the color pigment. Example 3 A moisture-proof paper was produced in the same manner as in Example 1 except that red (insoluble azo, TB-720, manufactured by Dainichiseika Kogyo) was used as the color pigment. Example 4 A moisture-proof paper was produced in the same manner as in Example 1 except that yellow (insoluble azo, TB-910, manufactured by Dainichiseika Kogyo) was used as the color pigment. Example 5 A moisture-proof paper was produced in the same manner as in Example 1 except that blue (copper phthalocyanine, TB-520, manufactured by Dainichiseika Kogyo) was used as the color pigment.

Comparative Example 1 A moisture-proof paper was obtained in the same manner as in Example 1 except that the color pigment was not added. Comparative Example 2 polyethylene unbleached both kraft paper (basis weight 70 g / m ²⁾ (density of ^{0.937g / cm 3, MFR 9.5g /} 10 minutes, manufactured by Showa Denko) was laminated 15 g / m ^2.

The moisture vapor transmission rates of the colored moisture-proof papers obtained in Examples 1 to 5 and Comparative Examples 1 and 2 were measured by JIS Z 0 208 (cup method) B method with the coated surface facing outside. In the case of a crease, the sample was folded in two and a machine calender was used to make a crease at a linear pressure of 50 kg / cm. After that, the sample was opened and the machine calender was used again to make a crease in the cross direction. Without folds 50g / m ² · 24hr hereinafter as a reference moisture permeability value, the creased is sufficiently practical when 100g / m ² · 24hr or less. In addition, it was visually evaluated whether the colored moisture-proof paper and the poly-laminated paper were visually distinguishable.

[0015]

[Table 1] As is clear from Table 1, the moisture-proof papers obtained in Examples 1 to 5 are apparently distinguishable from poly-laminated paper, and there is no adverse effect such as deterioration of the moisture-proof performance due to coloring.

[0016]

[Effect of device]

 The moisture-proof paper obtained by the present invention has a colored moisture-proof surface, so that the user can easily distinguish it from poly-laminated paper, and recovery and reuse can be very smooth.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a moisture-proof and waterproof paper according to the present invention.

[Explanation of symbols]

 1 Base paper 2 Moisture-proof layer containing color pigment

Claims (1)

[Scope of utility model registration request] 1. A moisture-proof and waterproof paper which is easy to be re-disintegrated, characterized in that it has a moisture-proof layer composed of latex, wax and color pigments on a base paper mainly composed of wood pulp.