JP2654815B2 - Eraser-containing microcapsules and manufacturing method thereof, and eraser containing the microcapsules - Google Patents

Description

The present invention relates to a microcapsule containing an erasing liquid, a method for producing the same, and an eraser containing the microcapsule. More specifically, the present invention relates to the volatilization and bleeding of the erasing liquid. The present invention relates to a microcapsule and a eraser that suppresses and prevents a decrease in eraser performance and commercial value.

[Conventional technology and problems]

Conventionally, various types of erasers containing an erasing liquid such as aqueous ink have been proposed. For example, JP-A-54-72
121 discloses an eraser in which an inorganic fine hollow body storing an eraser is disposed in an eraser. However, as the eraser, relatively volatile ethylene glycol,
When ethylene glycol monomethyl ether or the like is used, it is difficult to bleed, but the erasing liquid volatilizes and evaporates, and the erasing ability decreases with time. To prevent this, if diethylene glycol, triethylene glycol or the like having relatively low volatility is used, the erasing ability can be reduced over time, but bleeding becomes a serious problem.

On the other hand, Japanese Patent Application Laid-Open Nos. 56-36554 and 56-36555 propose erasers containing microcapsules or powders in which an eraser is adsorbed on an adsorbing substance, but these have the same problems as described above. In addition, there is a problem that the eraser substrate has a high sol viscosity and is difficult to process.

Japanese Patent Application Laid-Open No. 62-199498 discloses an eraser in which an erase solution is gelled with a gelling agent and a gel or wax-like fine powder is dispersed in a base resin. Therefore, there is a restriction that a gelling agent compatible with the erasing liquid must be selected.

[Means for solving the problem]

In view of the above circumstances, the present inventors have achieved the present invention as a result of intensive studies on character erasure without bleeding without a long-term decrease in erasing ability due to volatilization while containing a large amount of an erasing liquid and stably. It is.

That is, the first aspect of the present invention is a microcapsule containing an erasing liquid made up of hollow particles whose surfaces are covered with a polyurethane film, and the second aspect of the present invention is to store the erasing liquid in hollow particles. After letting
A method for producing a microcapsule containing an erasing liquid, comprising forming a polyurethane film on the surface of the hollow particles. The third aspect of the present invention is to provide a microcapsule containing the first erasing liquid of the present invention. The content of the eraser is contained.

As the erasing liquid used in the present invention, all solvents that swell or dissolve the vehicle resin of the aqueous ink or the drawing ink are used, for example, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol, diethylene glycol monoethyl ether , Diethylene glycol monoethyl ether acetate, triethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, oxyethylene dodecylamine,
Polyoxyethylene allylamine, alkylamine, dodecylamine, monoethanolamine, diethanolamine, ethyldiethanolamine, ethylene carbonate, propylene carbonate, ethyl lactate, cyclohexanecarboxylic acid, succinic acid, adipic acid, benzoic acid, citric acid, and the like. Are used alone or in combination of two or more.

Examples of the hollow particles used in the present invention include silica balloons, shirasu balloons, glass balloons, dia balloons, micro balloons, perlite, and other known inorganic or organic hollow particles such as phenol micro balloons.

As a method for inserting the above-mentioned erasing liquid into the hollow particles, a known method such as vacuum decompression and pressurization is used. The amount of the erasing liquid absorbed by the hollow particles is in the range of 100 to 300 parts by weight, preferably 150 to 250 parts by weight, per 100 parts by weight of the hollow particles.

The surface of the hollow particles storing the eraser liquid is covered with a film. As such a film, a polyurethane film is preferable. In this case, when the erasing liquid as the core substance does not react with the isocyanate, or when there is only one functional group that reacts with the isocyanate, a bifunctional or more functional substance having a higher reaction rate with the isocyanate than the erasing liquid is used as a curing agent or It is preferable to mix 1 to 10% by weight of the erasing liquid as a crosslinking agent. When the number of functional groups that react with isocyanate is two or more, only the eraser can be occluded as a core substance,
For the purpose of improving the heat resistance, chemical resistance, release property, etc. of the film material, it is preferable to mix a bifunctional or higher-functional material having a higher reaction rate with isocyanate than the eraser. The bifunctional or higher-functional substance having a high reaction rate used herein is a chain extender or a cross-linking agent generally used for polyurethane, such as ethylene glycol, 1,4-butanediol, glycerin, sorbitol, diphenylmethanediamine, m −
Phenylenediamine and the like.
Used as a mixture of more than one species. If the isocyanate is liquid at the reaction temperature, it is used as a raw material for the film substance, but if necessary, a dispersion medium may be used. In this case, it is not necessary to consider the compatibility of the dispersion medium with the isocyanate, but a poor solvent is used for the eraser so as not to extract the eraser in the hollow particles. For example, n-pentane, n-pentane
-Hexane, n-heptane, n-octane, isooctane, petroleum ether, ligroin, petroleum spirit, petroleum naphtha, cyclohexane, methylcyclohexane, ethylcyclohexane, benzene, toluene, etc. alone or 2
Used as a mixture of more than one species. In the reaction of the isocyanate, a catalyst is used as necessary. Tin thiocarboxylate,
Known ones such as lead octenoate are exemplified.

The eraser liquid-containing microcapsules obtained as described above are mixed with 10 to 100 parts by weight, preferably 30 to 60 parts by weight, based on 100 parts by weight of the base resin, and erased by press molding or the like. The base resin is composed of a resin such as a vinyl chloride paste, a plasticizer, a filler, a stabilizer, and the like.
180180 parts by weight, 1 to 3 parts by weight of stabilizer, and 0 to 120 parts by weight of filler are preferred.

〔Example〕

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited by these.

Example 1 A 2-necked round bottom flask was charged with 50 g of silica balloon (Q cell 300, Asahi Glass Co., Ltd.) as hollow particles.
Attach a dropping funnel containing 0 ml, connect to the vacuum pump and seal the other side, then depressurize the inside of the silica balloon shell by reducing the pressure with the vacuum pump, close the cock to the diffusion pump, and stop the cock of the dropping funnel. Was opened, ethylene glycol was added dropwise, and after the completion of the addition, the inside of the flask was returned to atmospheric pressure, the silica balloon was taken out, and the excess ethylene glycol was washed with acetone, filtered and dried to obtain a silica balloon occluded with ethylene glycol.

100 g of the silica balloon is placed in 800 ml of cyclohexane (0.001 g of dibutyltin laurate added as a catalyst) as a dispersion medium, and 3 g of liquid diphenyl diisocyanate (Sumidur 44V-20, Sumitomo Bayer Urethane Co., Ltd.) is gradually mixed with stirring. After heating at about 60 ° C. for about 1 hour, the mixture was filtered and dried to obtain microcapsules which occluded ethylene glycol and were covered with a polyurethane film.

Using this microcapsule, prepare the eraser base composition of the polyvinyl chloride (hereinafter referred to as PVC) paste sol shown below, defoam, cast into a press mold, heat to 130 ° C and press Was press-molded at a pressure of 20 kg / cm ² to obtain a eraser.

Erasing base compound: PSH-10 (PVC paste resin, manufactured by Kaneka Chemical Co., Ltd.) 100 parts by weight DOP 100 parts by weight Calcium carbonate 50 parts by weight Eraser-containing microcapsules 50 parts by weight Stabilizer for PVC 3 parts by weight Part Example 2 In Example 1, diethylene glycol was occluded in the same manner as in Example 1 except that 100 ml of diethylene glycol was used as the eraser, and 50 g of Shirasu balloon (Winlite 3011, Shiroishi Kogyo Co., Ltd.) was used as the hollow particles. Example 1 Microcapsules coated with a polyurethane film were obtained.
The same eraser base composition was obtained, and molded using the microcapsules under the same conditions as in Example 1 to obtain an eraser.

Example 3 In Example 1, 90 ml of polyethylene glycol and 10 ml of ethylene glycol were used as an eraser, 50 g of silica balloon (Godball E2C, Suzuki Yushi Co., Ltd.) was used as hollow particles, and an aliphatic polyisocyanate (N3200) was used as an isocyanate. Microcapsules were produced in the same manner as in Example 1 except that 5 g of Sumitomo Bayer Urethane Co., Ltd. was used.

Using this microcapsule, the same erased base material composition as in Example 1 was obtained, and molded under the same conditions as in Example 1 to obtain an eraser.

Comparative Example 1 In Example 1, the same eraser base composition as in Example 1 was obtained using microcapsules that occluded ethylene glycol before forming a polyurethane film, and were molded under the same conditions as in Example 1. I got erased.

Comparative Example 2 Microcapsules were produced in the same manner as in Example 1 except that 100 ml of diethylene glycol was used as the eraser solution and no polyurethane film was formed. Using this microcapsule, the same erased base material composition as in Example 1 was obtained, and molded under the same conditions as in Example 1 to obtain an eraser.

The erasure rate and bleedability of the erasers obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were measured. Table 1 shows the results. In addition, the measuring method is as follows.

A. Erase rate tracing film (SAURAI CO.LTD, S200, 50
μ) was cut into 50 x 50 mm, and a 6 mm wide straight line was drawn with a drawing pen for drawing (black ink for drawing) so that the lines did not overlap. , 10 times of abrasion. Using a test sample cut to 20 x 10 x 5 mm, the erasure rate was measured immediately after production of the eraser, and six months after production (stored in a desiccator with a desiccant), and the erasure rate changed over time. Was examined.

B. Bleedability The above eraser sample is desiccator (with desiccant)
For one week, and the surface of the sample was visually observed.

○: No bleed ×: With bleed As is evident from the results in Table 1, the eraser in Examples 1 to 3 did not show much reduction in the erase ratio even after half a year, showed a practically sufficient erase ratio, and no bleeding was observed. On the other hand, in the erasers of Comparative Examples 1 and 2, the erasure rate significantly decreased after half a year, and in the case of Comparative Example 2, bleeding was remarkably observed in addition to the decrease in the erasure rate.

[Action / Effect]

As described above, according to the present invention, a relatively large amount of erasing liquid can be stably contained during erasing, and the bleeding property is significantly improved while the decrease in erasing rate due to volatilization is suppressed. It is possible to provide a character eraser having excellent performance and merchantability.

Claims (3)

(57) [Claims] 1. A microcapsule containing an erasing liquid, comprising hollow particles which occlude the erasing liquid and whose surface is covered with a polyurethane film. 2. A method for producing microcapsules containing an erasing liquid, comprising the steps of: inserting an erasing liquid into hollow particles; and forming a polyurethane film on the surface of the hollow particles. 3. A character eraser comprising microcapsules containing the eraser liquid according to claim 1.