JPS6042320B2 - How to improve writing performance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for improving the writability of paper or plastic film by applying a treatment liquid mainly composed of fine hollow glass spheres such as Shirasu balloons and a binder to the surface of paper or plastic film. With the improved method, processed papers and plastic films with excellent writability can be easily obtained.

Conventionally, methods for improving the writability of paper, synthetic paper, plastic films, etc. include embossing or matting the base material itself, chemical treatment methods such as acid or alkali treatment, and inorganic white coating methods such as clay coating. Pigment coating methods can be broadly divided into pigment coating methods that use powder and binder.

Among these methods, the pigment coating method is useful for improving the printability and writability of paper, synthetic paper, etc., and has become popular. Most of the pigments used for this are inorganic white powders, and the types include titanium oxide, zinc oxide,
A wide variety of materials have been used, including calcium carbonate, magnesium carbonate, barium sulfate, talc, clay, silicic acid, and diatomaceous materials, but none have always been satisfactory. In the pigment coating method, instead of the conventionally used inorganic white powder, the present inventors have solved the conventional method by using fine hollow glass spheres called "silas balloons" alone or together with the inorganic white powder. They discovered that the writability was significantly improved compared to the previous one, and completed the present invention.

The present invention provides a treatment solution that is obtained by dispersing an appropriate amount of fine hollow glass spheres such as the above-mentioned Shirasu balloons in a binder, and coats paper or plastic film, etc., to easily form a coating layer, and then coats the paper or plastic film, etc. If you write it down, the spherical body will be destroyed by a weak force and turn into powder.

This phenomenon causes fine irregularities in the coated layer, which can improve writing properties with a pencil or the like. The above-mentioned Shirasu balloon is obtained by pulverizing fine sandy volcanic ash commonly known as Shirasu, sieving it, and heating and foaming the selected sand component in a roasting furnace, and its main components are silica and alumina (for example, SiO).

approx. 70%, Al2O3 approx. 15%, other approx. 15%, etc.)
・The particle size as a hollow spherical body is about 5 to 500μ, the bulk specific gravity is 0.12 to 0.32, and the melting point is 1200°C. Glass microballoons (trade name sold by Emerson and Cuming, USA) can also be used for the same purpose. A preferred composition of the treatment liquid in the present invention is as follows.
Binder: 1 part (weight and below) fine hollow glass spheres: 5 to 1 (1) parts Thickener: Appropriate amount Colorant: Appropriate amount: Surfactant: Appropriate amount: Solvent: 100 to 50% Blend of binder and fine hollow glass spheres in the above treatment solution The ratio is 1 (1) part of the former (same as below weight) to about 5 parts of the latter.
~1 (1) part is suitable; if the fine hollow glass spheres are less than 5 parts, the effect will not be seen, and it will be the same as that of a mixture of other inorganic white powders, and if it is more than 1 (1) part, it will not be effective. Not only does a part of the broken and powdered hollow glass spheres detach from the binder, but there are also difficulties in mixing technology and coating processing.

Conventionally known binders, solvents, thickeners, surfactants, etc. can be used. That is, the binder includes natural rubber latex, synthetic rubber latex, polyvinyl alcohol, gum arabic, gum tragacanth, methyl cellulose, glue, tin, starch, gelatin, vinyl chloride-vinyl acetate copolymer, polyvinyl chloride, polyvinyl acetate, chlorinated polypropylene, Examples include ethylene-vinyl acetate copolymer, polyacrylic acid ester, silicone resin, urethane resin, phenol resin, melamine resin, epoxy resin, tenpen resin, rosin and its derivatives, petroleum resin, and others. Further, as the solvent, benzene, xylene, toluene, acetone, methyl ethyl ketone, ethyl acetate, hexane, heptane, benzine, cyclohexane, water, methanol, etc. can be selected depending on the type of binder. The above treatment liquid is prepared by stirring and dissolving the binder in a suitable solvent, adding Shirasu balloons and, if necessary, a thickener, a coloring agent, and a surfactant, and thoroughly mixing and dispersing the binder with a stirring device.

Next, this treatment liquid is applied to the surface of a writing material such as paper using an appropriate coating machine such as an air knife, knife coater, or gravure coater so that the solid content is approximately 5 to 30 g/d, and is dried and solidified. to form a coating layer. In addition to paper, the above-mentioned writing materials include sheet-like materials such as synthetic paper, plastic film, and cloth. The particle size of the fine hollow glass spheres such as the above-mentioned Shirasu balloons is approximately 50 to 100μ when the purpose is to write with pencils, ballpoint pens, etc.If the viscosity is larger than this, ink will smear when written with a fountain pen etc. Also, if it is too small, it will have little effect.

Since the present invention is constructed as described above, the surface to be coated forms a coating layer mainly composed of fine hollow glass spheres and a binder, so that when written with a weak force using a pencil, ballpoint pen, etc. However, the fine hollow glass spheres are destroyed and minute irregularities occur on the surface of the coating layer, resulting in a roughened surface.

As a result, friction occurs between the writing instrument and the surface of the coating layer, and the adhesion of carbon, ink, etc. to the writing instrument and writing instrument is significantly improved.
Even if you write lightly with a hard pencil (for example, 9FI), you can write darkly and clearly. Next, examples of the present invention will be shown.

Example 1 Compounding of treatment liquid Natural rubber latex (solid content approximately 60%) 10 parts by volume Shirasu balloon 15 parts by weight Thickener
Appropriate amount of surfactant
appropriate amount of water
5 parts of saliva The above-mentioned Shirasu balloon, thickener, and surfactant are added to natural rubber latex, stirred and mixed, and water is added to adjust a treatment liquid of a predetermined viscosity.

This is coated on one side of high-quality printing paper with a basis weight of 96 g/TTI using a gravure type coating machine to give a solid content of approximately 10 g/Rrl.
After drying, coated paper was obtained. The properties of writing on the processed surface of the obtained coated paper with a pencil, ballpoint pen, etc. are superior to those using inorganic powder. Example 2
Treatment liquid formulation Chlorinated polypropylene 10 parts Shirasu balloon 25 parts by weight Surfactant
Appropriate amount of toluene
10 parts cyclohexane 10
Partially chlorinated polypropylene is stirred and dissolved in a mixed solvent of toluene and cyclohexane, and Shirasu balloons and a surfactant are added to prepare a coating treatment solution.

This was made from polypropylene with a thickness of 0.04Twt.
Approximately 10 g of the solid content was coated on one side of synthetic paper using an air knife type coating device and dried to obtain a coated sheet. The ability to write with pencils, ballpoint pens, etc. on the coated surface is untreated and corona treated. Superior to those coated with inorganic powder. Example 3 Combination of treatment liquid Vinyl chloride-vinyl acetate copolymer 10 parts Shirasu balloon 1 part surfactant
Appropriate amount of ethyl acetate
50 parts of coating treatment liquid prepared in the same manner as in Example 2 to a thickness of 0.04Tm! A gravure coating machine was used to coat one side of the n acetate film with a solid content of approximately 5 g/r! A coated sheet was obtained by coating and drying.

Claims (1)

[Claims] 1. On the surface of paper, synthetic paper, or plastic film, apply a processing solution containing 5 to 100 parts by weight of fine hollow glass spheres with a particle size of 50 to 100 μ per 100 parts by weight of the binder, based on the solid content in the processing solution. A method for improving the writability of the paper, synthetic paper, or plastic film, comprising coating the paper at a rate of 5 to 30 g/m^2 and drying to improve the writability of the paper, synthetic paper, or plastic film.