JPH031997A - Eraser compound - Google Patents

Abstract

PURPOSE:To prevent separation of a grinding material by allowing said grinding material processed by a coupling agent on the surface thereof to be included in an eraser compound. CONSTITUTION:A grinding material which is processed by a coupling agent on the surface thereof is included in this eraser compound having a thermo plastic elastomer as a base material. The thermoplastic elastomer has, in molecules thereof, both rubber components with elasticity and molecule constraining components preventing plastic deformation. For the thermoplastic elastomer, styrene ground, olefin group, ester group or urethane group is used. The grinding material is composed of glass powders, silica sand, quartz powders etc. Moreover, a silane coupling agent, a titanate couping agent or an eluminum coupling agent is used for the coupling agent to process the surface of the grinding material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an eraser composition based on a thermoplastic elastomer, and particularly relates to an eraser composition based on a thermoplastic elastomer. The present invention relates to an abrasive-containing eraser composition suitable for erasing handwriting and images on the surface layer of paper, such as images formed by copying methods, where ink and toner have not penetrated into the paper fibers.

(Prior art and its problems) In general, the surface of 5 papers has irregularities due to the overlapping of paper fibers, such as images printed with high viscosity ink, handwriting with oil-based ballpoint pens, and images formed by electrostatic copying. The ink and toner do not penetrate into the inside of the paper fibers, but instead penetrate into the irregularities of the paper fibers, so that they cannot be erased with a normal pencil eraser.

Conventionally, in order to erase these images and handwriting, an abrasive material is mixed and dispersed in a rubber base called a sand eraser, and then vulcanized. A method of erasing was used by peeling off the fibers. However, since the base material of this sand eraser is rubber and requires vulcanization, the vulcanization reaction is likely to proceed under the influence of sunlight and temperature, causing it to become hard and brittle, or to erase without producing any eraser residue. The performance deteriorates significantly, and the problem of deterioration of erasability due to deterioration of the base material over time cannot be solved.

On the other hand, polyvinyl chloride erasers, which are used as pencil erasers and are made by heating and molding plastisol that is a mixture of polyvinyl chloride, plasticizers, and fillers, have good erasing performance and do not cause the base material to deteriorate over time. However, in order to improve the migration problem such as the dissolution of paint applied to pencil barrels etc. due to the plasticizer used, mainly phthalate ester, and to improve the toxicity, we have developed a method that does not use phthalate ester plasticizer. Eraser base materials using thermoplastic elastomers, which are materials that do not require sulfur and have rubber elasticity, have been considered.

Examples of these materials include materials consisting of a low-crystalline polyolefin thermoplastic elastomer, a sub-filler, and optionally chlorinated polyethylene (Japanese Patent Publication No. 58-4072), and materials containing 10 to 40% by weight of butadiene. Items using styrene-butadiene-styrene block copolymer (JP-A-56
-429200), the proportion of styrene is 10~
Products using 20% by weight of styrene-isoprene-styrene block copolymer (JP-A-56-127498), ethylene-vinyl acetate copolymer and/or atactic polypropylene resin and styrene-butadiene copolymer and a plasticizer (Special Publication Publication No. 57-3)
2680 (Japanese Unexamined Patent Publication No. 19500/1983), and one made of a styrene thermoplastic elastomer, a hydrocarbon resin, and a polyolefin (Japanese Patent Application Laid-open No. 19500/1983).

Erasers based on these thermoplastic elastomers do not require the use of phthalate ester plasticizers, so there are no problems with migration or toxicity, and there is no need for vulcanization, so the vulcanization reaction progresses and becomes hard. It was possible to obtain an eraser that does not become soft, brittle, or leave no residue.

However, when these thermoplastic elastomers are used as a base material and an abrasive is added to the eraser in order to make the eraser capable of erasing the handwriting and images described above, the abrasive is an inorganic material and the surface becomes rough. It is covered with hydroxyl groups and exhibits hydrophilic properties, and therefore has poor adhesion to thermoplastic elastomer, which is an organic substance, and the abrasive material is not securely fixed in the eraser.Therefore, the abrasive material gets caught in the paper fibers during rubbing and erasing. The eraser leaked out from the eraser without being peeled off, resulting in an unsatisfactory erasing performance.

(Means for Solving the Problems) The gist of the present invention is to provide an eraser composition based on a thermoplastic elastomer, which is characterized in that it contains an abrasive whose surface has been treated with a coupling agent. It is something to do.

The present invention will be explained in detail below.

Thermoplastic elastomer is a polymeric material that exhibits the properties of vulcanized rubber at room temperature, but becomes plasticized at high temperatures and can be molded with a normal plastic molding machine. It has both molecular restraint components (hard segments) that prevent Thermoplastic elastomers are broadly classified into styrene-based, olefin-based,
It is divided into ester type, urethane type, and others. These styrene-based and olefin-based materials are preferred as eraser materials because they do not break too much and easily produce eraser residue.

Polystyrene-based thermoplastic elastomer is a styrene-butadiene-styrene structure that uses polybutadiene, polyisoprene, and ethylene-butylene saturated by hydrogenating polybutadiene as the rubber component, sandwiching it from both ends with polystyrene as a molecular restraint component. These are block copolymers, styrene-isoprene-styrene block copolymers, and styrene-ethylene-butylene-styrene block copolymers.

Specifically, examples of the styrene-based thermoplastic distomer include ``''Tuffprene A, Turprene T-411゜T-4'' and styrene-butadiene-styrene block copolymers.
14, T-475, Asaprene T-431 (manufactured by Asahi Kasei Corporation), Cariflex TR1101, TR11
02, TR1150, TRILL6, TR1184 (manufactured by Shell Chemical ■), Cariflex TR1107 as a styrene-isoprene-styrene block copolymer
, TRIII, TR1112, TRI l 17. Kraton D1320X (manufactured by Shell Chemical Company), Kraton G1650, G1652 as styrene-ethylene-butylene-styrene block copolymers. G1657
X (manufactured by Shell Chemical ■), and Lavalon 5E5400.5E6400.5E8 as a styrene-ethylene-butylene-styrene block copolymer compound.
400 (manufactured by Mitsubishi Yuka), etc.

A polyolefin thermoplastic elastomer is an olefin rubber such as butyl rubber (IIR) as a rubber component.
, ethylene propylene rubber (EPM) and ethylene propylene ternary copolymer rubber (EPDM) are used.The rubber component is partially crosslinked, and the rubber component is partially crosslinked and the molecules are bonded to each other. The constraint component is something that is grafted together. As a polyolefin thermoplastic elastomer,
Specifically, Namamugi TPE820, Resident TPE1500.
Sumitomo TPE1700 (Summiya Chemical Industry fill)
, Thermorun 3620.3700.3800 (manufactured by Mitsubishi Yuka), Milastomer 503ON, 603ON, 70
Examples include 3ON, 803ON, 8032N, and 902ON (manufactured by Mitsui Petrochemical Industries, Ltd.).

The abrasives used in the present invention include those conventionally used, specifically carborundum, fused alumina, glass powder, silica sand, quartz powder, shirasu, etc. The law is determined as appropriate depending on the size and amount of the person to be stripped. Among these abrasive materials, if a hard abrasive material is used and the eraser is molded using conventional plastic processing machines (extrusion molding machines, injection molding machines, etc.), these machines will be worn out by the abrasive material. glass powder, silica sand.

An abrasive whose main component is 5 iOz, such as quartz powder or glass, is preferable because it causes less wear on the plastic processing machine.

The surface of these abrasive materials is treated with a coupling agent, and examples of this coupling agent include silane coupling agents, titanate-based camping agents, and aluminum-based coupling agents.

Silane coupling agents have functional groups in their molecules that chemically bond with organic substances (amino group, mercapto group, epoxy group, vinyl group, methacrylic group, chloro group, etc.) and functional groups that chemically bond with inorganic substances (methoxy group, ethoxy group, etc.). It is an organosilicon with different functional groups such as cellosolve group, cellosolve group, etc. Specifically, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminomethyl)aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, Methoxysilane, γ-anilinopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, Y-
Mercaptopropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyljethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane Methoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, γ-
Examples include methacryloxypropyltrimethoxysilane, γ-gloropropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane. Commercially available products include TOμ Silicone 5.
H6020, 5Z6023, 5H6026, 5z603
0,5Z6032,5H6040,5Z6050.5H
6062,5Z6070,5Z6072.5H6075
,5H6076,5Z6079゜5Z6083,5Z6
300 (made by Tou μ Silicone ■), Shin-Etsu Silicone KA1003. KBC1003, KBE1003
．． KBM1003. KBM503. KBM303. KB
M403. KBM402, KBM603. KBM602
．． KBM903゜KBM573. KBM803. KBM703 (and above,
Shin-Etsu Chemical Co., Ltd.), NUC silicone A-143°A
-150, A-151, A-172, A-174゜A-
186, A-187, A-189, A-1100, A-
1120, A-1160 (manufactured by Nippon Unicar) Sila x, -XS210, 8220, 5230.3310
,8311,5320,5321゜5330,5510
．． 5520.5530, 5610.8620, 5710
, 5810 (all manufactured by Chisso ■), etc.

Titanate-based coupling agents and aluminum-based coupling agents are organic titanium and organic aluminum that have in their molecules a functional group that chemically bonds with inorganic substances and a portion that is compatible with organic substances.

Specifically, as a titanate coupling agent.

Isopropyl triisostialoyl titanate, isopropyl tris(dioctylpyrophosphate) titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl) -1-butyl)bis(ditridecyl)phosphite titanate-1~, bis(dioctylpyrophosphate)oxyacetate titanate-1-, bis(dioctylpyrophosphate)ethyl titanate, isopropyltrioctanoyl titanate, isopropyl dimethacrylic isostearoyl Commercially available titanates include isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, and tetraisopropyl bis(dioctyl phosphite) titanate. , Plain Act KRTT
S, KR388, KR44゜KR46B, KR55, K
R138SS, KR238S, 338X, KR2S, K
R7゜KR9S, KR11, KR12, KR34S, K
R41B (Ajinomoto 11111), Citacoat S-151, S-152, S-153, S-231, P
-151, R-161, R-291, C-151, C-
231 (manufactured by Nippon Soda), etc.

Acetalkoxyaluminum diisopropylate is a commercially available product as an aluminum-based packaging agent.
There is Plain Act AL-M (manufactured by Ajinomoto ■).

When the abrasive material is actually treated with a coupling agent, the following three methods are generally employed. That is, ■Integral blend method: Direct coupling agent.

Alternatively, a method in which a material dissolved in an appropriate plasticizer is added to the eraser base material before or after the abrasive material is kneaded.

(2) Dry pretreatment method: A method in which a coupling agent, either directly or dissolved in a small amount of water and/or an appropriate solvent, is dropped or sprayed onto the abrasive material being stirred.

■Wet pretreatment method: A method in which a coupling agent is dissolved in a large amount of water or an appropriate solvent, and this is stirred and mixed with an abrasive material, and then the water or solvent is appropriately distilled off or filtered, compressed, and dried.

The amount of this coupling agent to be used should be determined depending on the specific surface area of each abrasive, but it is preferably approximately 0.05% by weight or more. Even if the amount of coupling agent is too large, the excess coupling agent can be removed together with the filtrate by performing filtration using method (2) above. Incidentally, these coupling agents can be used alone or in combination of two or more kinds. In particular, when a silane coupling agent and a titanate-based or aluminum-based coupling agent are used together, it is preferable to perform each treatment separately. Further, when the main component of the polishing agent is SiO2, a silane coupling agent is particularly effective.

Furthermore, in order to make the effect of the coupling agent more effective, the surface of the abrasive material treated with the coupling agent is coated with a thin layer of thermoplastic elastomer, and this is heated to 140°C or higher, preferably 180°C or higher, and polished with the thermoplastic elastomer. Use a crosslinkable thermoplastic elastomer to melt or coat the material, add a crosslinking agent or vulcanization accelerator to the thermoplastic elastomer in advance, and vulcanize it when heated to create a thermoplastic elastomer. can be chemically bonded with a silane coupling agent. Even if the thermoplastic elastomer coated at this time is slightly deteriorated by heating, it accounts for a small proportion in the eraser, so there is no problem with the eraser performance.

In addition, stabilizers, colorants, etc. can be added to the eraser composition according to the present invention as needed (function). Since the surface is treated with a coupling agent, the thermoplastic elastomer, which is the base material of the eraser, and the abrasive material are firmly bonded using the coupling agent as an intermediary, which prevents the abrasive material from coming off when the eraser rubs and erases as much as possible. As a result, the advantages of erasers based on thermoplastic elastomers can be utilized. In other words, when the hydroxyl groups on the surface of the abrasive material and the coupling agent combine through dehydration or dealcoholization reactions, the surface of the abrasive material is covered with the camping agent, which becomes organic and has particularly good adhesion between the base material and the abrasive material. becomes.

(Example) Hereinafter, the present invention will be explained in more detail based on Examples.

Example 1 Treatment of abrasive material> KP Vermis, KP-60F 100 parts by weight (Shirasu, manufactured by Kyoritsu Ceramic Materials) 5 parts by weight of TO-μ Silicone 5H60260 (silane coupling agent, manufactured by TO-μ Silicone ■, effective) Ingredients: 40% methanol solution crystals) Water: 6 parts by weight A silane coupling agent is dissolved in water and hydrolyzed, then sprayed onto a stirring KP-60F, and then dried to form an abrasive material treated with a coupling agent. Obtained.

Manufacturing method of eraser> Turprene T-47525 parts by weight (manufactured by styrene thermoplastic elastomer chemical industry) Milastomer 603ON 25 parts by weight (
Olefinic thermoplastic elastomer manufactured by Mitsui Petrochemical Industries Ltd.) IRGANOXIOIO 0.2 parts by weight (stabilizer, manufactured by CIBA-GEIGY) Cronos KA-
106 parts by weight (titanium oxide, manufactured by Titanium Kogyo ■) Coupling agent treated abrasive material 84.3 parts by weight 120
Turprene T-475 and Milastomer 603ON are thoroughly kneaded using two rolls heated to 0.degree. C., and the remaining ingredients are added and kneaded. The kneaded product was placed in a mold and press-molded at 120° C. for 10 minutes to obtain a block-shaped eraser containing abrasive material.

Example 2 <Treatment of abrasive material> Crystallite granular 80-150Mesh (quartz powder, manufactured by Tatsumori) 50 parts by weight Toto μ silicone 5H6
0750, 2 parts by weight (silane coupling agent, manufactured by TOμ Silicone ■) Water 200 parts by weight After dissolving the silane coupling agent in water and hydrolyzing it, put crystallite particles in it, then suction filtration and drying. An abrasive material treated with a coupling agent was obtained.

Manufacturing method of eraser> Turuprene T-41425 parts by weight (manufactured by Styrenic Thermoplastic Elastomer Kasei Kogyo ■) Evaflex 210 25 parts by weight (ethylene-vinyl acetate copolymer resin).

(manufactured by DuPont Mitsui Polychemicals@) IRQANOXlolo 0.2 parts by weight Surface-treated abrasive material 50.2 parts by weight An abrasive-containing eraser was obtained in the same manner as in Example 1.

Example 3 <Treatment of abrasive material> WA 3320 60 parts by weight (fused alumina: Fujimi abrasive material industrial music @) Titacoat S
231 1.5 parts by weight (titanate coupling agent).

Active ingredient 80% IPA solution (manufactured by Nippon Soda n) IAP (isopropyl alcohol) 5 parts by weight After dissolving the titanate coupling agent in IPA, it was injected into WA #320 while stirring, and then dried and made into a cup. An abrasive material treated with a ring agent was obtained.

Manufacturing method of eraser> Clayton 01650 20 parts by weight (Styrenic Elasto Shell Kagakuboku Co., Ltd.) UBE L519
20 parts by weight (polyethylene: manufactured by Ube Industries) Alcon P-12510 parts by weight (alicyclic saturated hydrocarbon resin: manufactured by Aurayo Forestry Chemical Industry @) IRGANollolo 0.2 parts by weight The above-mentioned coupling agent treated abrasive material 61.2 Parts by weight Heavy calcium carbonate 25 parts by weight Same as Example 1.

Comparative Examples 1 to 3 are the same as Examples 1 to 3 in which an abrasive material without coupling agent treatment was used.

(Effect of the invention) As described above, using the erasers obtained in Examples 1 and 2.3 and Comparative Examples 1 and 2.3, an oil-based ballpoint pen (BK-70, manufactured by Bentel! 41) was drawn on high-quality paper. ) was erased and the reflection density was measured using a photographic densitometer.
Reflection density 0.10 Ballpoint pen handwriting n
o, s.

By preventing separation, -/IF can exhibit excellent erasing performance.

Claims (1)

[Claims] An eraser composition based on a thermoplastic elastomer, characterized in that it contains an abrasive whose surface has been treated with a coupling agent.