JP2022099185A - Eraser - Google Patents

Abstract

To provide an eraser excellent both in erasability and hardness difficult to be bent.SOLUTION: An eraser of the present invention includes vinyl chloride resin, plasticizer, and filler. The plasticizer includes chemicals having dissolution parameters of 9.2 to 11.0, wherein chemicals having dissolution parameters are at least one chemical selected from the group consisting of phthalate ester, benzoic acid ester, and phosphate ester.SELECTED DRAWING: Figure 1

Description

The present invention relates to an eraser, and more particularly to an eraser having an eraser property.

The eraser (eraser) is roughly classified according to the type of the base resin, for example, a vinyl chloride eraser made of a vinyl chloride resin, a non-vinyl chloride eraser made of a styrene-based thermoplastic elastomer or an olefin-based thermoplastic elastomer, and a natural rubber character. Eraser can be mentioned.

In the eraser, when the load applied to the contact surface when pressed against the paper increases, the contact area between the paper and the eraser increases, so that the erasability is improved. Here, if the hardness of the eraser is low, this contact area increases, and it is considered that the eraseability is improved. However, if the eraser is greatly deformed when the eraser is pressed against the paper and rubbed, the erasability is rather deteriorated. This is because the low hardness of the eraser acts on the deformation when pressed against the paper, the load applied to the contact surface between the eraser and the paper does not increase so much, and it easily follows the paper when rubbed on the paper. This is because it is deformed and less likely to be worn.

In order to enhance the erasability of the eraser, for example, Patent Document 1 discloses an eraser having an appropriate hardness by combining a vinyl chloride resin with a specific plasticizer and further adding a filler. In the eraser, the filler merely functions as a disintegrating material. For this reason, it has been pointed out that while improving the erasability, the erasing itself is easily broken by repeated rubbing on the paper.

On the other hand, Patent Document 2 discloses that a benzoic acid ester-based plasticizer is blended with a vinyl chloride resin to form an eraser without using a disintegrating material. However, the eraser molded only by the combination of such a plasticizer and a vinyl chloride resin is still soft, and further improvement for enhancing the eraser property is desired.

Japanese Unexamined Patent Application Publication No. 2003-07229 Japanese Unexamined Patent Publication No. 2011-10894

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an eraser excellent in both erasability and fragility.

The present invention is an eraser containing a vinyl chloride resin, a plasticizer and a filler.
The plasticizer comprises a compound having a dissolution parameter of 9.2 to 11.0.
The compound having the dissolution parameter is erasable, which is at least one compound selected from the group consisting of phthalates, benzoic acids and phosphates.

In one embodiment, the content of the plasticizer is 120 parts by mass to 200 parts by mass, and the content of the filler is 0.1 parts by mass to 225 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. Is.

In a further embodiment, the content of the filler is 10 parts by mass to 225 parts by mass with respect to 100 parts by mass of the vinyl chloride resin.

In one embodiment, the filler is at least one selected from the group consisting of calcium carbonate, talc and silica.

In one embodiment, the hardness according to JIS S 6050 (2002) in the eraser of the present invention is 55 to 80.

In one embodiment, the upper surface and the lower surface of the test piece cut into a size of 55 mm in length × 25 mm in width × 11.5 mm in thickness in the erasing of the present invention are formed on the upper surface with respect to the long side surface (length direction). The average number of times the test piece is broken is 100 or more when the lower surface is held by the thumb with the index finger and the middle finger and the test piece is repeatedly bent and released as one operation by crushing the test piece. ..

According to the present invention, it is possible to maintain excellent erasability, to be hard to break, and to provide a sticky feeling of use. This frees you from the mental burden of using it while being careful not to break it unexpectedly, and you can erase characters, line diagrams, etc. with fewer operations.

It is a photograph for demonstrating the operation which repeats bending and releasing of a test piece when measuring the average number of times of bending of the test piece made from the eraser of this invention.

Hereinafter, the present invention will be described in detail.

The eraser of the present invention contains a vinyl chloride resin as a base resin.

The vinyl chloride resin is, for example, a vinyl chloride resin having an average degree of polymerization of 650 to 4000, preferably 800 to 2500, and more preferably 1100 to 1500. In the present invention, if the average degree of polymerization of the vinyl chloride resin is less than 650, the hardness of the obtained eraser may be lowered and sufficient eraser may not be obtained. When the average degree of polymerization of the vinyl chloride resin exceeds 4000, the obtained eraser is less likely to be scraped and the eraser may be inferior.

The vinyl chloride resin may be a homopolymer of vinyl chloride, or a copolymer containing mainly vinyl chloride as a constituent unit and as a comonomer such as vinyl acetate, ethylene, methyl acrylate, and methyl methacrylate. In the present invention, the vinyl chloride resin is preferably composed of a vinyl chloride homopolymer because the erasability can be improved.

In the present invention, the base resin may contain other resins or rubbers in addition to the vinyl chloride resin as long as it does not impair the erasability and breakability of the eraser described later. Examples of other resins include styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, acrylic-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, nylon-based thermoplastic elastomers, and the like. And chlorinated polyethylene copolymer crosslinked alloys, and thermoplastic elastomers such as combinations thereof. Other rubbers include, for example, natural rubbers and synthetic rubbers, and combinations thereof. Specific examples of synthetic rubbers include isoprene rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber, and acrylonitrile butadiene rubber, and diene rubbers such as combinations thereof; and butyl rubber, ethylene / propylene rubber, urethane rubber, silicone. Examples include rubber, chlorosulfonated polyethylene, chlorinated polyethylene, acrylic rubber, epichlorohydrin rubber, and fluororubber, as well as non-diene rubbers such as combinations thereof.

The eraser of the present invention also contains a plasticizer.

The plasticizer is added to impart appropriate flexibility and frictional resistance to the resulting eraser. The plasticizer constituting the eraser of the present invention is a compound having a dissolution parameter (sp value) of 9.2 to 11.0, preferably 9.4 to 10.5, and more preferably 9.6 to 10.0. including. By including a compound having a dissolution parameter in such a range as the plasticizer, the plasticizer can enhance the compatibility with the vinyl chloride resin, improve the erasability, and provide a hard-to-break eraser.

Examples of compounds having the above range of dissolution parameters that may be included in the plasticizer include benzoic acid esters, phosphate esters, and phthalates, and combinations thereof. Specific examples of the benzoic acid ester include diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, and combinations thereof. Specific examples of the phosphoric acid ester include tricresyl phosphate, trixylenyl phosphate, and combinations thereof. Specific examples of phthalates include benzyl butyl phthalate. In the present invention, it is preferable to use a benzoic acid ester because it is a material that is more friendly to the natural environment and thereby enhances the appeal of the product.

In the present invention, the plasticizer may contain other plasticizers in addition to the compound having the above-mentioned dissolution parameter. Other plasticizers do not satisfy the above-mentioned solubility parameter range (9.2 to 11.0), and for example, tributyl acetylcitrate (ATBC) (sp value 9.0), dioctyl phthalate (DOP). (Sp value 8.9), dioctyl adipate (DOA) (sp value 8.5), and combinations thereof can be mentioned.

In the present invention, the content of the compound having a dissolution parameter in the above range that can constitute the plasticizer is preferably 40% by mass to 100% by mass, more preferably 70% by mass to 100% by mass based on the total mass of the plasticizer. %. When the plasticizer contains a compound having a dissolution parameter in the above range in such a ratio, the plasticizer enhances the compatibility with the vinyl chloride resin, improves the erasability, and makes the erasable hard to break. Can be provided.

In the present invention, the content of the plasticizer is not necessarily limited, but is preferably 120 parts by mass to 200 parts by mass, and more preferably 140 parts by mass to 180 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. When the content of the plasticizer is less than 120 parts by mass, the obtained eraser is hard, and the adhesiveness is lowered, so that the eraser may be lowered. If the content of the plasticizer exceeds 200 parts by mass, the hardness of the eraser decreases, and it may be too soft and difficult to use.

The eraser of the present invention also contains a filler.

The filler provides a predetermined hardness for the combination of the vinyl chloride resin and the plasticizer, and when the obtained eraser is pressed against the paper and rubbed, an appropriate load is applied to the contact surface between the eraser and the paper. Plays such a role.

Examples of such fillers are calcium carbonate (eg, heavy calcium carbonate and light calcium carbonate), talc, silica, diatomaceous earth, magnesium oxide, sericite, quartz powder, montmorillonite, and shell powder (eg, scallops, etc.). Calcium, shijimi, etc.), and combinations thereof. Calcium carbonate, talc and silica, and combinations thereof, because they are highly versatile for erasing and can provide even better erasing properties for the combination of the vinyl chloride resin and the plasticizer. Is preferable.

In the present invention, the content of the filler is not necessarily limited, but is preferably 0.1 part by mass to 225 parts by mass, more preferably 10 parts by mass to 225 parts by mass, still more preferably, with respect to 100 parts by mass of the vinyl chloride resin. Is from 50 parts by mass to 180 parts by mass. When the content of the filler is less than 0.1 part by mass, the obtained eraser is soft and may be significantly deformed when pressed against paper and rubbed, while the eraser may be deteriorated. If the content of the filler exceeds 225 parts by mass, the obtained eraser becomes hard, and the surface of the eraser may be cracked or easily broken due to continuous rubbing on the paper.

The eraser of the present invention may contain other components as long as it does not impair the eraser property and the crease resistance achieved from the combination of the vinyl chloride, the plasticizer and the filler. Examples of such other components include stabilizers and colorants and combinations thereof.

The stabilizer is generally used in the field of resin molding, and is preferably a heat stabilizer of a vinyl chloride resin. Examples of heat stabilizers for vinyl chloride resins include metal soaps with metals such as barium, zinc and calcium and organic acids such as stearic acid, lauric acid, ricinoleic acid, naphthenic acid and 2-ethylhexoic acid. Other examples of stabilizers include antioxidants, UV absorbers, and light stabilizers. Examples of antioxidants include hindered phenolic antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. Examples of the ultraviolet absorber include a benzotriazole-based ultraviolet absorber, a triazine-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, a cyanoacrylate-based ultraviolet absorber, a salicylate-based ultraviolet absorber, and an oxanilide-based ultraviolet absorber. Examples of light stabilizers include various hindered amine light stabilizers, oxalic acid derivatives, salicylic acid derivatives, and hydrazine derivatives.

The colorant is preferably a general-purpose colorant for vinyl chloride resins. Examples of colorants include inorganic pigments, organic pigments, disperse dyes, and reactive dyes.

The content of the above other components is not particularly limited and may be appropriately selected by those skilled in the art.

The eraser of the present invention has the following various physical characteristics.

For example, in the eraser of the present invention, the hardness according to JIS S 6050 (2002) (plastic eraser) is preferably 55 to 80, more preferably 60 to 75. When the hardness satisfies such a range, the obtained eraser can obtain an appropriate frictional force and adhesiveness with the paper surface requiring the eraser, and as a result, the eraser becomes erasable. You can get an expensive and easy-to-use eraser.

Alternatively, in the erasing of the present invention, the upper surface and the lower surface of the test piece cut into a size of 50 mm in length × 25 mm in width × 11.5 mm in thickness are the index finger and the middle finger on the upper surface with respect to the long side surface (length direction). Then, the lower surface is held by the thumb ((a) in FIG. 1), and the test piece is bent by crushing the test piece ((b) in FIG. 1) and released ((a) in FIG. 1). The average number of times the test piece is broken when repeated as one operation is preferably 100 times or more, more preferably 200 times or more. The average number of times such a test piece is broken is calculated as the average value of the number of times obtained by preparing two test pieces and measuring the number of times the test piece is bent and released. .. When the average number of folds satisfies such a range, the obtained eraser is not easily broken at the time of erasing and has sufficient strength to withstand practicality.

The eraser of the present invention can be produced by melt-kneading the above components and then heat-molding. Examples of the molding method include press molding, injection molding, and extrusion molding. As a specific example, the eraser of the present invention is produced by kneading the above components with a blender to prepare a sol, defoaming the sol, placing it in a mold to gel it, and then pressing it at a predetermined pressure. Can be done. The molding temperature is not necessarily limited, but is, for example, 100 ° C. to 130 ° C., preferably 110 ° C. to 120 ° C., and the heating time is, for example, 20 minutes to 40 minutes. After cooling, the eraser of the present invention can be obtained by removing it from the mold.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

The following evaluations were performed on the samples obtained in the examples and comparative examples described later.

(Hardness)
The hardness of the obtained sample was measured according to JIS S 6050 (2002).

(HB pencil erasure rate)
The HB pencil erasure rate of the obtained sample was measured according to JIS S 6050 (2002).

(Average number of breaks)
The sample was cut into a size of 55 mm in length × 25 mm in width × 11.5 mm in thickness to prepare a test piece, and the upper surface and the lower surface of the obtained test piece were formed on the upper surface with respect to the long side surface (length direction). Hold the lower surface with the thumb with the index finger and the middle finger ((a) in FIG. 1), and bend the test piece by crushing the test piece ((b) in FIG. 1) and release it ((a) in FIG. 1). ) And was repeated as one operation, and the number of times until the test piece was broken was measured. This measurement was performed on two test pieces, and the average value thereof was taken as the average number of breaks.

(Example 1: Preparation of sample (E1))
100 parts by mass of paste-like vinyl chloride resin (PQ140 manufactured by Shin-Daiichi PVC Co., Ltd .; average degree of polymerization 1210 to 1410), 160 mass of plasticizer (PN6120 manufactured by ADEKA Co., Ltd .; benzoic acid ester-based plasticizer, sp value 9.8) 30 parts by mass of stabilizer (for vinyl chloride resin), 10 parts by mass of calcium carbonate (NS1000 manufactured by Nitto Powder Industry Co., Ltd.) and silica (VN3 manufactured by Toso Silica Co., Ltd.) at 115 ° C. After kneading for a minute, it was molded by an extruder to obtain a sample (E1). The average thickness of this sample (E1) was 11.5 mm. The evaluation results of the sample (E1) are shown in Table 1.

(Examples 2 to 3 and Comparative Examples 1 to 2: Preparation of samples (E2) to (E3) and (C1) to (C2))
Corresponding samples (E2), (E3), in the same manner as in Example 1 except that the paste-like vinyl chloride resin, plasticizer, filler and stabilizer and molding conditions shown in Table 1 were used. (C1) and (C2) were prepared. For these samples, the average thickness in the thickness direction was 11.5 mm due to heat shrinkage after cooling. The evaluation results of the samples (E2), (E3), (C1) and (C2) are shown in Table 1.

As shown in Table 1, the samples (E1) to (E3), (C1) and (C2) prepared in Examples 1 to 3 and Comparative Examples 1 and 2 all have substantially the same hardness. The erasure rate was also good. On the other hand, the samples (E1) to (E3) prepared in Examples 1 to 3 showed a significantly higher average number of folds than the samples (C1) to (C2) of Comparative Examples 1 and 2. From this, the samples (E1) to (E3) prepared in Examples 1 to 3 have an excellent eraser rate and a stickiness that is hard to break as compared with the samples (C1) to (C2) of Comparative Examples 1 and 2. It turns out that it was an eraser with.

(Examples 4 to 10: Preparation of samples (E4) to (E10))
Corresponding samples (E4) to (E10) were prepared in the same manner as in Example 1 except that the paste-like vinyl chloride resin, the plasticizer, the filler and the stabilizer and the molding conditions shown in Table 1 were used. Made. For these samples, the average thickness in the thickness direction was 11.5 mm due to heat shrinkage after cooling. The evaluation results of the samples (E4) to (E10) are shown in Table 1.

As shown in Table 2, as the content of the filler is increased (Examples 4 to 8), the average number of breaks tends to decrease, but the content of calcium carbonate is very high as in Example 8, for example. Even if it is set, the obtained sample (E8) shows a value having a higher average number of folds than the samples (C1) and (C2) of Comparative Examples 1 and 2 in Table 1 above, and is difficult to fold. I understand that.

Claims (6)

An eraser containing vinyl chloride resin, a plasticizer and a filler.
The compound having the dissolution parameter is at least one compound selected from the group consisting of phthalates, benzoic acids and phosphates, erasable. The content of the plasticizer is 120 parts by mass to 200 parts by mass, and the content of the filler is 0.1 parts by mass to 225 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. Erasing described in. The eraser according to claim 2, wherein the content of the filler is 10 parts by mass to 225 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. The eraser according to any one of claims 1 to 3, wherein the filler is at least one selected from the group consisting of calcium carbonate, talc and silica. The eraser according to any one of claims 1 to 4, wherein the hardness according to JIS S 6050 (2002) is 55 to 80. Hold the upper and lower surfaces of the test piece cut into a size of 55 mm in length × 25 mm in width × 11.5 mm in thickness with the index finger and the middle finger and the lower surface with the thumb with respect to the long side surface (length direction). The present invention according to any one of claims 1 to 5, wherein the average number of times the test piece is broken when the test piece is repeatedly bent and released by crushing the test piece as one operation is 100 or more. Erasing.

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