JP4633777B2 - Erasure - Google Patents

Description

  The present invention relates to erasing, and more specifically, the frictional resistance with the paper surface is small when erasing the handwriting without erasing without reducing the erasing property, that is, the erasing feeling is light, and the feeling of use and usability are easy. Regarding good erasing.

  The erasing mechanism is based on the fact that the erasure adheres to the handwriting on the paper and adsorbs the handwriting to the erasure, and the surface portion of the erasure that adsorbs the handwriting is removed from the erasure as a scrap. This is done by renewing the erased surface so that the handwriting can be adsorbed again.

  Thus, when the frictional resistance is large when the eraser is rubbed closely against the handwriting on the paper, the feeling of erase becomes heavy and the usability and usability deteriorate. Accordingly, a material having a low frictional resistance and a light sensation is required.

However, in reality, there have been few attempts to lighten the erasing feeling when erasing characters.
In particular, in recent years, from the viewpoint of environmental conservation, the erased base material has tended to move from vinyl chloride resin to styrene resin, olefin resin, ethylene-vinyl acetate resin, rubber, etc. When trying to lighten the erasing feeling of vinyl chloride resin or rubber as a base material, the erasing rate tends to decrease, and erasing that sufficiently satisfies the erasing property and erasing feeling has not yet been proposed. The fact is not.

  In view of such a situation, the present invention provides a erasure that is easy to use and easy to use, with a lighter erasure feeling without lowering the erasure rate.

  As a result of diligent research to solve the above problems, the present inventors have included a polypropylene polymer (A) and a glass bead (B) polymerized with a metallocene catalyst, thereby erasing without reducing the erasure rate. It has been found that it is possible to lighten the feeling, provide a comfortable and easy-to-use erasure, and have reached the present invention.

That is, the present onset Ming, styrene resins, olefin resins, ethylene - vinyl acetate resin, a substrate selected from among rubber and polypropylene polymer polymerized by metallocene catalyst (A) and glass beads ( B) a Ru eraser vegetables contain,
When the substrate is a styrene resin , the polypropylene polymer (A) polymerized with a metallocene catalyst is 1 to 40 parts by weight with respect to 99 to 60 parts by weight of the styrene resin substrate, and the glass beads (B) but Ri 1-400 parts by der the total 100 parts by weight of styrene-based resin base material and a metallocene catalyst polymerized polypropylene polymer (a),
When the substrate is an olefin resin , the polypropylene polymer (A) polymerized with a metallocene catalyst is 1 to 40 parts by weight with respect to 99 to 60 parts by weight of the olefin resin substrate, and the glass beads (B) but Ri 1-400 parts by der the total 100 parts by weight of an olefin resin base material and a metallocene catalyst polymerized polypropylene polymer (a),
When the substrate is an ethylene-vinyl acetate resin , the polypropylene polymer (A) polymerized with a metallocene catalyst is 1.6 to 53 with respect to 98.4 to 47 parts by weight of the ethylene-vinyl acetate resin substrate. The glass beads (B) are 1.6 to 640 parts by weight with respect to a total of 100 parts by weight of the ethylene-vinyl acetate resin base material and the polypropylene polymer (A) polymerized with a metallocene catalyst. Oh it is,
When the base material is rubber , the polypropylene polymer (A) polymerized with the metallocene catalyst is 4 to 160 parts by weight with respect to 100 parts by weight of the rubber base material, and the glass beads (B) are the rubber base material 100. The eraser is characterized by being 4 to 1600 parts by weight with respect to parts by weight.

  According to the present invention, it is possible to lighten the erasing feeling without reducing the erasure rate, and it is possible to provide erasing that is comfortable to use and easy to use.

The inventors of the present invention have previously found that by including a polypropylene polymer polymerized with a metallocene catalyst for erasing, the erasing feeling can be reduced without reducing the erasure rate, and a patent application has been filed ( Japanese Patent Application No. 2002-162822).
Thereafter, the inventors of the present invention subsequently studied erasing with excellent erasing rate and erasing feeling, and as a result, by incorporating glass beads together with a polypropylene polymer polymerized with a metallocene catalyst for erasing. I found that the purpose of the period can be achieved.

That is, the present invention is an eraser characterized by comprising a specific base material, a polypropylene polymer (A) polymerized with a metallocene catalyst, and glass beads (B) in a specific blending ratio. (Claim 1).

As the substrate used in the present invention , styrene-based, olefin-based, ethylene-vinyl acetate-based, rubber-based substrates are suitable, and these are used alone or in combination of two or more as required. Styrene-based, olefin-based, and rubber-based substrates are suitable.

  Examples of the styrene-based substrate include styrene-isoprene-styrene copolymer, styrene-ethylenebutylene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-ethylenepropylene-styrene copolymer, and styrene-based heat. Styrenic thermoplastic elastomers such as plastic elastomer compounds may be mentioned, and these may be used alone, but are preferably used in combination of two or more. Further, it may be combined with other base materials.

  Examples of the olefin-based substrate include Sumitomo TPE (Sumitomo Chemical Co., Ltd.), Miralastomer (Mitsui Chemicals Co., Ltd.), ethylene-α olefin copolymer, propylene-α olefin copolymer, ethylene-α olefin copolymer. (Metallocene catalyst), amorphous polyalphaolefin, high density polyethylene, low density polyethylene, ultra low density polyethylene, polypropylene, and other olefinic elastomers may be mentioned. These may be used alone, but preferably used in combination of two or more. It is done. Further, it may be combined with other base materials.

  Examples of the ethylene-vinyl acetate base include Evaflex (trade name, Mitsui DuPont Polychemical Co., Ltd.) and Ultrasen (Tosoh Corp.). These may be used alone, but preferably two or more types. Used in combination. Further, it may be combined with other base materials.

  Examples of the rubber base material include IIR (butyl rubber), IR (isoprene rubber), SBR (styrene-butadiene rubber), BR (butadiene rubber), EPM (ethylene propylene rubber), EPDM (ethylene propylene terpolymer). ), Acrylic rubber, polyisobutylene, and NR (natural rubber). These may be used alone or in combination of two or more. Further, it may be combined with other base materials.

  The polypropylene polymer (A) polymerized with a metallocene catalyst is a polypropylene obtained by polymerizing with a metallocene catalyst or a polypropylene copolymer mainly composed of polypropylene. For example, a propylene / ethylene / random copolymer “WINTECH” XK-1160 "," Wintech XK-1159 "," Wintech XK-1181 "(all trade names manufactured by Nippon Polychem Co., Ltd.). These may be used alone or in combination of two or more as required.

  The content of the polypropylene polymer (A) polymerized with the metallocene catalyst varies depending on the type of the base resin, but in the case of a styrene base material, it is 1 to 40 weights with respect to 99 to 60 parts by weight of the styrene resin. Part is preferred. The more preferable content considering the erasability is 1 to 15 parts by weight with respect to 99 to 85 parts by weight of the styrene resin, and the more preferable content is 3 to 15 parts by weight with respect to 97 to 85 parts by weight of the styrene resin. It is.

  In the case of an olefin base material, it may be the same as that of a styrene base material, and is 1 to 40 parts by weight with respect to 99 to 60 parts by weight of the olefin resin. The more preferable content considering the erasability is 1 to 15 parts by weight with respect to 99 to 85 parts by weight of the olefin resin, and the more preferable content is 3 to 15 parts by weight with respect to 97 to 85 parts by weight of the olefin resin. is there.

  In the case of an ethylene-vinyl acetate base material, the amount is 1.6 to 53 parts by weight with respect to 98.4 to 47 parts by weight of the ethylene-vinyl acetate resin. The more preferable content considering the erasability is 1.6 to 23 parts by weight with respect to 98.4 to 77 parts by weight of the ethylene-vinyl acetate resin, and the more preferable content is 95 to 95 ethylene-vinyl acetate resin. It is 5 to 23 parts by weight with respect to 77 parts by weight.

  In the case of a rubber-type base material, it is 4-160 weight part with respect to 100 weight part of rubber | gum. The more preferable content considering the erasability is 4 to 60 parts by weight with respect to 100 parts by weight of rubber, and the more preferable content is 12 to 60 parts by weight with respect to 100 parts by weight of rubber.

  Examples of the glass beads (B) include soda lime glass beads and low alkali glass beads. For example, “Uni Beads UB-06L”, “Uni Beads UB-34L”, “Uni Beads UB-56L”, “Uni Beads UB-06MF”. (All are trade names of Union Co., Ltd.), “J-80”, “J-100” (both are trade names of Potters Barotini Co., Ltd.), and the like.

  The content of the glass beads (B) is 100 parts by weight of the total of the base material and the polypropylene polymer (A) polymerized with the metallocene catalyst. Part by weight is preferred, more preferably 2 to 400 parts by weight. In the case of an ethylene-vinyl acetate resin base material, the amount is preferably 1.6 to 640 parts by weight, more preferably 3.2 to 640 parts by weight. Furthermore, in the case of a rubber base material, 4 to 1600 parts by weight is preferable with respect to 100 parts by weight of the rubber base material, and more preferably 8 to 1600 parts by weight. If the content of the glass beads (B) is less than the lower limit, the effect of improving the erasing feeling is not sufficient.

  The eraser of the present invention further includes, as necessary, shell calcium powder such as heavy calcium carbonate, light calcium carbonate, silica, diatomaceous earth, magnesium oxide, talc, sericite, quartz powder, montmorillonite, scallop, oyster, squeeze, etc. Other additives such as fillers, organic hollow particles, inorganic hollow particles and coloring materials such as organic / inorganic pigments, dyes, fragrances, stabilizers, lubricants, antioxidants, ultraviolet absorbers, and fungicides are also optional. It can also be used. Further, by adding a microcapsule encapsulating a solvent that dissolves ink or the like, or an abrasive that wears away ink handwriting, it is possible to provide erasing that can be erased other than pencil handwriting.

  The eraser composition of the present invention comprising the above components is kneaded, molded by press molding, injection molding, extrusion molding, or the like, and cut into a predetermined size to obtain a product.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example and a comparative example, these do not restrict | limit the scope of the present invention at all.

  The materials used in the following examples and comparative examples are shown in Table 1. In the following description, “parts” represents “parts by weight” unless otherwise specified.

Examples 1-32 and Comparative Examples 1-4
As shown in Tables 2 to 5, a styrene-based substrate, an olefin-based substrate, an ethylene-vinyl acetate (EVA) -based substrate, and a rubber-based substrate are used, and each of these substrates is polymerized with a metallocene catalyst. The polypropylene polymer (A), the glass beads (B), and the resin composition further blended with a filler were kneaded and mixed, and then a sample was obtained by extrusion molding with a mold having a predetermined size. In the case of a rubber-based substrate, a vulcanization operation was performed.
For each sample, the erasure rate and erasing feeling were measured and evaluated by the following methods. The results are shown in Tables 2-5.

Measurement method of erasure rate (from JIS-S-6050):
(1) The sample was cut into a plate having a thickness of 5 m / m, and the test piece was prepared by finishing the contact portion with the test paper into an arc having a radius of 6 m / m.
(2) The test piece is brought into contact with the colored paper perpendicularly and at right angles to the colored line, and a weight is placed on the test piece so that the sum of the weight of the weight and the holder is 0.5 kg. The colored part was brushed back and forth 4 times at a speed of 150 ± 10 cm / min.
(3) Using a densitometer (DENSITOMETER PDA65 made by Sakura), the density of the non-colored part of the colored paper was set to 0, and the density of the colored part and the erosion part was measured.
(4) The erasure rate was calculated by the following formula.
Erase rate (%) = (1− (density of wear part ÷ density of colored part)) × 100

Disappearance:
Friction resistance when the handwriting was erased using a sample was based on the following evaluation criteria, based on the case where the polypropylene polymer (A) polymerized with a metallocene catalyst was contained without containing glass beads (B). A four-step evaluation was made. The results are shown in Tables 2-5.
As is clear from the results of Tables 2 to 5, it can be seen that the quenching feeling is improved by including the polypropylene polymer (A) polymerized with the metallocene catalyst and the glass beads (B).

A: Very light.
○: Lightened.
□: A little lighter.
X: Not changed.

Examples 33-56
The same operation was performed except that the type of the glass beads (B) was changed, and the same evaluation was made. The results are shown in Tables 6-9. As is clear from the results of Tables 6 to 9, it can be seen that even when the type of glass beads (B) is changed, the erasing feeling is improved.

  As described above, the eraser of the present invention comprising a polypropylene polymer polymerized with a metallocene catalyst and glass beads is excellent in eraser feeling without deteriorating erasability, and is comfortable to use and easy to use. It is good.

Claims (1)

It contains a base material selected from a styrene resin, an olefin resin, an ethylene-vinyl acetate resin, and a rubber, a polypropylene polymer (A) and a glass bead (B) polymerized with a metallocene catalyst. an eraser that,
When the substrate is a styrene resin , the polypropylene polymer (A) polymerized with a metallocene catalyst is 1 to 40 parts by weight with respect to 99 to 60 parts by weight of the styrene resin substrate, and the glass beads (B) but Ri 1-400 parts by der the total 100 parts by weight of styrene-based resin base material and a metallocene catalyst polymerized polypropylene polymer (a),
When the substrate is an olefin resin , the polypropylene polymer (A) polymerized with a metallocene catalyst is 1 to 40 parts by weight with respect to 99 to 60 parts by weight of the olefin resin substrate, and the glass beads (B) but Ri 1-400 parts by der the total 100 parts by weight of an olefin resin base material and a metallocene catalyst polymerized polypropylene polymer (a),
When the substrate is an ethylene-vinyl acetate resin , the polypropylene polymer (A) polymerized with a metallocene catalyst is 1.6 to 53 with respect to 98.4 to 47 parts by weight of the ethylene-vinyl acetate resin substrate. The glass beads (B) are 1.6 to 640 parts by weight with respect to a total of 100 parts by weight of the ethylene-vinyl acetate resin base material and the polypropylene polymer (A) polymerized with a metallocene catalyst. Oh it is,
When the base material is rubber , the polypropylene polymer (A) polymerized with the metallocene catalyst is 4 to 160 parts by weight with respect to 100 parts by weight of the rubber base material, and the glass beads (B) are the rubber base material 100. An eraser characterized by being 4 to 1600 parts by weight with respect to parts by weight.