JPS6028307B2 - Vinyl chloride resin composition for erasing characters - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vinyl chloride resin composition for erasing.

Regarding erasers, various improvements have been made to their raw material composition, shape, etc., but in recent years, more emphasis has been placed on not only practical aspects but also decorative and toy elements. It is becoming more sophisticated and diversified.

In order to satisfy these demands, it is thought to be advantageous to use a raw material composition made of general-purpose synthetic resin as the main ingredient and mold it into various shapes; No method or raw material composition has been developed for this purpose.

For example, in the past, there was a casting method in which a paste sol made by mixing pinyl chloride resin produced by an emulsion polymerization method with plasticizers, fillers, pigments, etc. was poured into a mold and molded, and the sol was semi-melted in an extruder. A method is known in which an eraser in a desired shape is obtained by a sol extrusion method in which the material is solidified in a semi-gel state and then molded again using an extruder.

However, when using the above casting method, only monochromatic products can be obtained, and the shapes are often simple due to yield issues, making it difficult to respond to diversification, and the productivity is extremely low, making it unsuitable for mass production.

In addition, the above-mentioned sol extrusion method has the advantage of being able to respond to diversification in terms of shapes, patterns, etc. compared to the casting method, but in order to obtain the eraser effect, it is necessary to extrude in a semi-molten state. However, since the raw material composition is a paste sol, it is extremely difficult to process, and the productivity is not always good.

On the other hand, when pinyl chloride resin produced by suspension polymerization or bulk polymerization is extrusion molded or injection molded with plasticizers, fillers, etc., gelation progresses rapidly, resulting in poor yield. The molded products produced had no eraser effect, and for this reason, the vinyl chloride resin was considered unsuitable for erasers.

However, the present inventors have conducted various studies on vinyl chloride resin produced by such suspension polymerization method or bulk polymerization method, and as a result, it has become possible to produce an eraser with excellent eraser effect with extremely good productivity. A raw material composition was developed.

That is, the present invention is based on the weight part of the vinyl chloride resin 10 produced by a suspension polymerization method or a bulk polymerization method.

'3 to 10 parts by weight of acrylic resin, 50 parts by weight of plasticizer
The present invention relates to a vinyl chloride resin composition for erasing, comprising: -30 parts by weight of a filler, and 0-60 parts by weight of a filler.

To explain this, the vinyl chloride resin used in the present invention as the T component is a copolymer mainly composed of polyvinyl chloride or polypynyl chloride produced by a suspension polymerization method or a bulk polymerization method. Comonomers used in this copolymer include vinylidene chloride, vinyl acetate, acrylic acid and its esters, acrylonitrile, maleic acid and its esters or anhydrides, fumaric acid and its esters, ethylene, propylene. Examples include olefins such as, and vinyl esters.

These vinyl chloride-based resins must have a rating of 1,000 to 350 and a rating of 1,200 to obtain a product with excellent erasing effects.
It is desirable that the polymer has an average degree of polymerization of 3,500 to 3,500. On the other hand, various conventionally known acrylic resins can be used as the 'o} component, including acrylic resins, acrylonitrile-butadiene-styrene copolymer (ABS resin), methyl methacrylate-styrene copolymer (ABS resin), methyl methacrylate-styrene copolymer (ABS resin), Examples include butadiene-styrene copolymer (M-curve S resin), acrylonitrile-styrene copolymer (AS resin), acrylonitrile-acrylic co-styrene copolymer (AAS resin), and crosslinked acrylic rubber.

These acrylic resins are blended to appropriately suppress gelation from proceeding rapidly during heat molding of the composition, and in order to advantageously achieve the purpose of suppressing gelation, , {vinyl chloride resin 10 which is the component
It is necessary to mix 3 to 10 parts by weight of this 'o} component per part by weight, and in particular, from the viewpoint of erasing effect and cost, the range of 5 to 5 parts by weight is desirable.

The combination of this [〇} component suppresses the progress of gelation during heat molding, and due to the unique action of this component, the resulting product has performance as an eraser, that is, it has a large frictional resistance and is easily abraded. becomes. In addition, this 'o} component includes styrene-butadiene rubber,
When non-crosslinked rubber such as nitrile-butadiene rubber is used, it is compatible with the plasticizer described later, so it dissolves and swells, making it impossible to achieve the goal of suppressing gelation. Therefore, it is not possible to obtain a product with an excellent eraser effect.

Plasticizers as one component are essential in order to provide appropriate frictional resistance to products, and include various types of plasticizers conventionally used in vinyl chloride resins, such as di-2-ethylhexyl phthalate and dibutyl phthalate. phthalate ester plasticizers such as, adipic ester plasticizers such as di-2-ethylhexyl adibate, sebacate ester plasticizers such as di-2-ethylhexyl sepacate,
Examples include polymer plasticizers such as polyester and polyurethane.

These plasticizers are required to be used in an amount of 50 to 30 parts by weight based on 10 parts by weight of the pinyl chloride resin as the 'i' component.

If this amount is less than 5 parts by weight, the resulting product will have low acid resistance and will have poor erasing performance, while if it is more than 300 parts by weight, the product will be too soft and the surface will contain plasticizer. begins to pre-lead. Although the inclusion of a filler as a W component is not necessarily essential, it is effective in imparting appropriate frictional resistance and abrasion resistance to the product, and calcium carbonate is a filler used for this purpose. Examples include carbonates such as silica, clay, talc, glass powder, silicates such as silica sand, and metal hydrates such as aluminum hydroxide.

When blending these fillers, if the proportion is too large, the rubber elasticity of the product will decrease and the product will break during use. It should not exceed 60 parts by weight. The vinyl chloride resin composition for erasing of the present invention can be obtained by mixing each of the above-mentioned components in predetermined amounts, but it can also contain stabilizers, lubricants, colorants, fragrances, etc. as necessary. There is no problem in doing so.

Mixing may be carried out using conventionally known means such as a Henschel mixer, Banbury mixer, ribbon blender, etc. The vinyl chloride resin composition thus obtained can be easily made into an eraser product having a desired shape by extrusion molding or injection molding.

The conditions for extrusion molding are a back pressure of 30 to 100k9/
The molding temperature may be 80 to 140°C, and the conditions for injection molding are to use a molding machine with a nozzle cross-sectional area of 1.0 to 5.0°C and to set the molding temperature to 80 to 14°C. desirable. Next, reference examples and examples will be described, and the symbols used in each example have the following meanings.

TK-1300: Suspension polymerized vinyl chloride resin, polymerization degree 13
00 (trade name manufactured by Shin-Etsu Chemical) GB-1550: Bulk polymerized vinyl chloride resin, degree of polymerization 1500 (trade name manufactured by Saint-Gobain) TK-2500: Suspension polymerized vinyl chloride resin, degree of polymerization 2450 (trade name manufactured by Shin-Etsu Chemical) ) E-15: Emulsion polymerized pinyl chloride resin, degree of polymerization 1450 (trade name manufactured by Shin-Etsu Chemical Co., Ltd.)
MC-1200: Suspension polymerized vinyl chloride resin-vinyl acetate copolymer resin, degree of polymerization 1200 (product name manufactured by Shin-Etsu Chemical Co., Ltd.) B
-12: Methyl methacrylate-butadiene-styrene copolymer (M Shigeru resin) (trade name manufactured by Kanebuchi Chemical Co., Ltd.) SE-5
0: Acrylonitrile-butadiene-styrene copolymer (A spot resin) (trade name manufactured by Kanekabuchi Kagaku Co., Ltd.) KM-32$: Crosslinked acrylic rubber (manufactured by Rohm and Haas Co., Ltd.) N-23 Eaves: Nitrile-butadiene Rubber (product name manufactured by Japan Synthetic Rubber Co., Ltd.) Whiten SB: Childhood calcium carbonate (manufactured by Shiroishi Calcium Co., Ltd.) DOP: D-2-ethylhexyl phthalate D
BP: Dibutyl phthalate Reference Example 1 The formulations shown in Table 1 (Experiments No. 1 to No. 8) were charged into a Henschel mixer and mixed at 120°C.

The mixture no. 1~No. As for No. 7, these were kneaded for 5 minutes at 13,000 yen using a 6-inch roll, and then heated and press-molded at a temperature of 13,030 yen and a pressure of 30 k9/c to obtain a test sheet. Also, experiment no. The mixture (paste sol) No. 8 was poured into a mold and heated at 14,000 for 10 minutes to obtain a test sheet.

The "slip resistance" and "abrasion loss" of each sheet thus obtained were measured, and the results were as shown in Table 1.

Slip resistance: Measured according to JISA 1407.

Wear loss: Using a taper abrasion tester, wear theory H-2
2. Measured at 1000 rotations. In Table 1, experiment no.
．． 1~NO. No. 4 has the composition of the present invention, but No. 4 has the composition of the present invention. 5
~No. No. 7 has a component corresponding to the 'o-component of the present invention or lacks it, and No. No. 8 is a case where emulsion polymerized pinyl chloride resin is used.

From this result, Experiment No. 1~No. 4 is experiment no. 5～
No. Compared to Test No. 7, the slip resistance and abrasion loss are greater, and because of this, the letter erasing effect is excellent. It can be seen that it is better than 8. Table 1 Reference Example 2 Test sheets were prepared in the same manner as in Reference Example 1 using the formulations shown in Table 2 (Experiments No. 9 to No. 15).

The "slip resistance" and "abrasion loss" of the sheet thus obtained were measured, and the results were as shown in Table 2.

In Table 2, Experiment No. 9~NO. No. 12 has the composition of the present invention, but No. 12 has the composition of the present invention. 13~No. 15 is a composition outside the present invention, and from these results, the blending amount of the acrylic resin corresponding to the 'low' component of the present invention is 3 to 10 parts by weight per 10 parts by weight of the vinyl chloride resin. It is preferable to keep the temperature within this range, and it can be seen that good results cannot be obtained when, for example, N-23 eaves, which do not fall under the 'o) component, are used (Experiment No. 15).

Table 2 Reference Example 3 Combination recipe shown in Table 3 (Experiment No. 16 to No. 23)
Test sheets were made in the same manner as in Reference Example 1 for each of the following.

The "slip resistance" and "abrasion loss" of the sheets thus obtained were measured and were as shown in Table 3.

In Table 3, Experiment No. 16~No. No. 20 has the composition of the present invention, but No. 20 has the composition of the present invention. 21~No. 23 is a composition outside the present invention, and from these results, the blending amount of the plasticizer corresponding to the first component of the present invention is (i) vinyl chloride resin 10
It is preferable to range from 50 to 30 parts by weight per part by weight of the filler, and the amount of filler corresponding to 0 component is {
It can be seen that the amount is preferably 60 parts by weight or less per 10 parts by weight of the pinyl chloride resin.

In other words, if the amount of plasticizer is too small (Experiment No. 21), no improvement in the erasing effect can be expected; on the other hand, if it is too large (Experiment No. 2)
2) Do not dry up. Furthermore, if the amount of filler is too large (Experiment No. 23), the product becomes hard and brittle and loses its marketability as an eraser. Table 3 Example 1 Experiment No. 1 in Reference Example 1 above. 1 and NO. The mixture according to the formulation of No. 5 was extruded into a square twill of IQ rib x l ratio using a 30 mm single screw extruder manufactured by Nippon Extron ■ under the following temperature conditions.

Cylinder part 1: 110q0 Cylinder part 2: 70qo Head part: 12bi○ Die part: 120pm○ A test was actually conducted to erase pencil handwriting on paper using each of the molded products obtained in this way. , it was as follows.

Experiment No. In the case of combination recipe No. 1: The erasing effect is extremely good. For example, in Experiment No.
It was equivalent to or better than a molded product obtained by casting the paste sol according to No. 8 (erasing by conventional method).

Experiment No. In the case of the formulation No. 5: The molded article had a low surface slip resistance and was not easily abraded, so the erasing effect was poor and it could not be put to practical use.

Example 2 Experiment No. 2 in Reference Example 1 above. 3 and no. The mixture according to the formulation No. 6 was injection molded into a square shape of 1 ratio x IQ mosquito x 12 ratio using an injection molding machine manufactured by Japan Steel Works, Ltd. under the following temperature conditions.

Cylinder part: 110 o Nozzle part: 10 o o When we actually conducted a test to erase pencil handwriting on paper using each of the molded products obtained in this way, Experiment No. In the case of compounding recipe No. 3, the above compounding recipe No. 3 is used.
Although it showed an excellent eraser effect similar to the result of No. 1, combination formulation No. In the case of No. 6, the eraser effect was poor and could not be put to practical use.

As can be seen from the above reference examples and examples, the polyvinyl chloride resin composition for erasing of the present invention not only provides a product with excellent erasing effect by molding methods such as extrusion molding and injection molding, but also provides a shape of the product. It has the characteristic that it can be mass-produced without being influenced by

Claims (1)

[Claims] 1 (a) 100 parts by weight of vinyl chloride resin produced by suspension polymerization method or bulk polymerization method, (b) acrylic resin 3
100 parts by weight of a vinyl chloride resin composition for erasing, (c) 50 to 300 parts by weight of a plasticizer, and (d) 0 to 600 parts by weight of a filler.