JPH02133476A - Microcapsule containing liquid eraser, its production, and eraser containing the same microcapsule - Google Patents

Abstract

PURPOSE:To obtain the title microcapsule stably containing a large amount of a liquid eraser and being useful for obtaining an eraser which does not undergo a decrease in an erasing capability due to volatilization by allowing hollow particles to occlude a liquid eraser and forming films on the surfaces of the hollow particles. CONSTITUTION:Hollow particles (e.g., silica balloons) are allowed to occlude a liquid eraser, desirably, a solvent which can dissolve or swell a vehicle resin of a water-based ink or a drafting ink, for example, a substance containing at least two isocyanate-reactive functional groups (e.g., ethylene glycol) and the hollow particles are added to, for example, a dispersing medium (e.g., cyclohexane). To this dispersion is added an isocyanate compound (e.g., diphenyl diisocyanate) under agitation to form, desirably, a polyurethane film on the surface. In this way, the title microcapsules comprising surface-coated hollow particles occluding the liquid eraser can be obtained.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to microcapsules containing an eraser, a method for producing the same, and an eraser containing the microcapsules described in I. suppresses bleed,
This invention relates to microcapsules and erasers that prevent deterioration in eraser performance and commercial value.

[Prior art and problems]

Conventionally, various types of erasers containing erasers such as water-based inks have been proposed. For example, JP-A-54-7
No. 2121 discloses an eraser in which a microscopic inorganic hollow body that occludes an eraser is arranged in an eraser. However, when relatively volatile ethylene glycol, ethylene glycol monomethyl ether, etc. are used as the eraser, although bleeding is difficult, the eraser evaporates and evaporates.
Erasing ability decreases over time. To prevent this, diethylene glycol, which has relatively low volatility,
If triethylene glycol or the like is used, the deterioration of erasing ability over time can be improved, but bleeding becomes a major problem.

On the other hand, JP-A-56-36554 and JP-A-5636555
There have been proposals for erasers containing microcapsules or powders in which the eraser is adsorbed to adsorbent materials, but these also have the same problems as above, and the sol viscosity of the eraser base material is high, making it difficult to process. The problem is that it is difficult.

Furthermore, JP-A-62-199498 discloses an eraser in which the eraser is gelled with a gelling agent and gel-like or wax-like fine powder is dispersed in the base resin. However, there is a constraint that a gelling agent must be selected that is compatible with the eraser.

[Means for solving problems]

The inventors of the present invention were aware of this situation, and as a result of intensive research into an eraser that stably contains a large amount of erasing fluid, does not reduce the erasing ability over time due to volatilization, and does not involve bleed, the present invention was developed. It has been reached.

That is, the first aspect of the present invention is a microcapsule containing the erasing liquid, which is made up of hollow particles whose surfaces are coated with a membrane and which occludes the erasing liquid. The third aspect of the present invention provides a method for producing microcapsules containing an eraser of the present invention, which is characterized in that a film is formed on the surface of the hollow particles. Each content is an eraser containing a capsule.

As the erasing fluid used in the present invention, any solvent that swells or dissolves the vehicle resin of water-based ink or drafting ink can be used, such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol, diethylene glycol monoethyl ether, etc. , diethylene glycol heptanoethyl ether acetate, triethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, oxyethylene dodecylamine, polyoxyethylene allylamine, alkylamine, dodecylamine, mononibnolamine, jetanolamine, ethyl jetanolamine , ethylene carbonate, propylene carbonate, ethyl lactate, cyclohexanecarboxylic acid, succinic acid, adipic acid, benzoic acid, citric acid, etc., and these may be used alone or in a mixture of two or more.

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

As a method for occluding the erasing liquid in the hollow particles, known methods such as vacuum reduction, pressurization, etc. can be used. The amount of erasing liquid to be occluded in the hollow particles is 1001iffi of the hollow particles.
100 to 300 parts by weight, preferably 150 to 2 parts by weight
The range is 50 parts by weight.

The surfaces of the hollow particles that have occluded the erasing liquid are covered with a film. For example, a polyurekne film is suitable as such a film. In this case, if the eraser as a core substance does not react with isocyanate, or if there is only one functional group that reacts with isocyanate, a difunctional or more functional substance that reacts faster with isocyanate than the eraser is used as a curing agent or a crosslinking agent. It is preferable to mix 1 to 10% of the compound into the eraser as an agent. In addition, when there are two or more functional groups that react with isocyanate, only the eraser can be occluded as a core material, but in order to improve the heat resistance, chemical resistance, sustained release properties, etc. It is preferable to mix a difunctional or higher functional substance that has a high reaction rate with 2-t. The difunctional or more functional substances used here that limit the reaction rate include chain extenders or crosslinking agents commonly used in polyurethane, such as ethylene glycol, 1,4-butanediol, glycerin, sorbitol, diphenylmethanediamine, Examples include m-phenylenediamine, which may be used alone or in combination of two or more. If the isocyanate is liquid at the reaction temperature, it can be used as it is as a raw material for the membrane material, but a dispersion medium can also be used if necessary. In this case, it is not necessary to consider the compatibility of the molecular l&solvent with the isocyanate, but a poor solvent is used for the eraser so as not to extract the eraser from the hollow particles, such as n-pentane, n-hexane, N-hebutane, n-octane, isooctane, Ishiichiyama ether, ligroin, petroleum spirit, petroleum natsuta, cyclohexane, methylcyclohexane, ethylcyclohexane, benzene, toluene, etc. may be used alone or in combination of two or more. Further, in the reaction of isocyanate, a catalyst is used as necessary, and such catalysts include dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin mercaptide, and dibutyltin mercaptide. Known examples include tin thiocarboxylate and lead octenoate.

The erasing liquid-containing microcapsules obtained as described in Section 2 above are mixed with 10 to 100 parts by weight, preferably 30 to 60 parts by weight, per 100 parts of the base resin, and are made into erasers by press molding or the like. The base resin consists of resins such as vinyl chloride paste, plasticizers, fillers, stabilizers, etc.
As an example of the mixing ratio, it is preferable to use 70 to 180 parts by weight of a plasticizer, 1 to 3 parts by weight of a stabilizer, and 0 to 120 parts by weight of a filler per 100 parts by weight of a base resin.

〔Example〕

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

Example 1 Silica balloons (Q
Put 50g of Cell 300 and Asahi Glass (2), attach a dropping funnel containing 100g of ethylene glycol as an eraser to one side of the flask, connect it to a vacuum pump and seal it to the other side. After degassing the inside of the shell of the silica balloon by reducing the pressure with a vacuum pump, close the cock to the diffusion pump, open the cock of the dropping funnel and drip ethylene glycol, and after the dripping is complete, return the inside of the flask to atmospheric pressure and release the silica balloon. was taken out, filtered and dried while washing excess ethylene glycol with acetone to obtain a silica balloon occluded with ethylene glycol. 100 g of this silica balloon was mixed with cyclohexane as a dispersion medium (0.001 g of dibutyltin laurate was added as a catalyst). 8
0〇-While stirring, gradually added 3 g of liquid diphenyl diisocyanate (Sumidur 44V-20, Sumitomo Bayer Urethane (Public 1)), and heated to about 1
After heating for a period of time, the mixture was filtered and dried to obtain microcapsules which occluded ethylene glycol and were coated with a polyurethane film.

Using these microcapsules, a polyvinyl chloride (hereinafter referred to as PvC) paste sol eraser base material composition shown below was prepared, and after defoaming, it was cast into a press mold and heated to 130°C.
After heating it to , it was press-molded at a pressure of 20 kg/cj to obtain an eraser.

Eraser base material composition: PSH-10 (PVC paste resin, Kanebuchi Chemical Industry)
5ri 100 parts by weight DOP 'l OO Calcium carbonate 50 Microcapsule containing erasing liquid 50pvc River stabilizer
3 Example 2 In Example 1, diethylene glycol 100. Shirasu balloon (Winlight 3011, Shiroishiko i fIi+) 5 as a hollow particle using nl
Except for using 0 g, diethylene glycol was occluded in the same manner as in Example 1 to obtain microcapsules coated with a polyurethane film, the same erasing base material composition as in Example 1 was obtained, and the microcapsules were used It was molded under the same conditions as Example 1 to obtain an eraser.

Example 3 In Example 1, polyethylene glycol 90- and ethylene glycol 1Qml were used as the eraser, silica balloons (G, Dopol E2C1 Suzuki Oil 9m>50g) were used as the hollow particles, and oil-based polyisocyanate (N3200. Microcapsules were produced in the same manner as in Example 1, except that 5 g of Sumitomo Bayer Urethane Ql) was used.

Using this microcapsule, the same eraser 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 material composition as in Example 1 was obtained using microcapsules occluded with ethylene glycol before forming a polyurethane film, and molded under the same conditions as in Example 1. I got the eraser.

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

The eraser rate and bleedability of the erasers obtained in Examples 1 to 3 and Comparative Example 1.2 were measured.

The results are shown in Table 1, and the measurement method is as follows.

8. Erasing rate tracing film (SAυl?AI Co, LT)
D, 5200.50μ) was cut out to 50 x 50 am, and a straight line with a width of 6 mm was drawn with a drafting pen (black ink for drafting) so that the cotton did not overlap, and the test paper was used, and the load was 600 g. In accordance with JIS S GO50, the test was performed with 10 times of 7 erasing. The test sample was cut to 20×IQ×5mm, and the eraser rate was measured immediately after manufacturing and six months after manufacturing (stored in a desiccant-containing resodicator), and changes over time in the eraser rate were investigated. .

B. Bleeding property The above eraser sample was left in a desiccator (containing desiccant) for one week, and the surface of the sample was observed with the naked eye.

○No nib bleed

Claims (1)

[Scope of Claims] 1. Microcapsules containing an erasing fluid and consisting of hollow particles that occlude the erasing fluid and whose surfaces are coated with a membrane. 2. The microcapsule according to claim 1, wherein the membrane is a polyurethane membrane. 3. A method for producing microcapsules containing an eraser, which comprises occluding the eraser into hollow particles and then forming a film on the surface of the hollow particles. 4. The manufacturing method according to claim 3, wherein the film is a polyurethane film. 5. An eraser containing microcapsules containing the eraser according to claim 1.