JPH0133161B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for molding footwear members that integrate dissimilar rubber pieces used as footwear members such as outsoles, midsoles, and insoles. (Prior Art) Conventionally, in a method of molding a shoe sole that integrates dissimilar rubber pieces, a partition wall is partially protruded from a mold, that is, a molding surface, as shown in Utility Model Publication No. 33-6084, and the partition wall is used to After filling the divided compartments with unvulcanized foreign rubber pieces and setting the unvulcanized shoe sole-based molding material in this mold by a conventional method, A method of forming shoe soles has been proposed in which the shoe sole is integrated with a rubber piece and vulcanized by heating and pressurizing it. When this molding method is used, the molding voids for the dissimilar rubber pieces are separated by partition walls, so unvulcanized dissimilar rubber pieces may flow into the sole-main molding voids during the heating and pressurizing process, or conversely, unvulcanized This prevents the sole-based molding material from flowing into the molding void of the foreign rubber piece, resulting in a shoe sole in which the boundary between the foreign rubber piece and the sole body is clearly separated, and even today, shoe sole molding is still effective. has been compensated for. However, in the sole obtained by this method, a groove is formed at the boundary between the foreign rubber piece and the sole main body, corresponding to the partition wall of the mold, so the adhesive strength between the sole main body and the foreign rubber piece of the shoe sole is strong. It has a drawback in terms of durability. Also, in the past
According to No. 25857, the sole molding material is divided into a sole main part made of semi-vulcanized rubber, a tread part and a heel part made of semi-vulcanized rubber, and each divided part is bonded with adhesive. A method has been proposed in which the materials are integrated by heating and pressurizing and vulcanizing, but this method has the disadvantage that the molding process is complicated and the cost is high. (Problems to be Solved by the Invention) The present invention aims to eliminate these drawbacks and provide a footwear member that is easy to mold, has excellent durability, and in which the dissimilar rubber piece and the main body are clearly separated. It is something to do. (Means for Solving the Problems) This invention proposes that 20 to 400 parts of diene rubber be added to 100 parts by weight of 1.2 polybutadiene with a degree of crystallinity of 10 to 40%.
A main molding material 1 made of an unvulcanized rubber dough mainly composed of parts by weight and having a notch partially with respect to the molding surface 301 of the mold 3 is set on the molding surface 301 of the mold 3. Main molding material 1
The molding surface 301 of the mold 3 corresponding to the notch 11 of
In addition, the molding surface 30 is different from the main molding material 1.
After setting the insert member 2 made of foamable unvulcanized rubber having a vulcanized rubber layer 21 on the surface opposite to the insert member 1, the main molded material 1 and the insert member 2 are integrated by heating and pressurizing. The gist of the invention is a method for molding a footwear member that integrates dissimilar rubber pieces, which is characterized by being vulcanized at the same time. Used as the main molding material in the present invention
1.2 Polybutadiene with a crystallinity of 10 to 40% is used from the viewpoint of physical properties and moldability, but for example, polybutadiene from Japan Synthetic Rubber Co., Ltd.
Particularly suitable are those with a crystallinity of 15 to 35%, offered under the trade names JSR, RB810, RB820, RB830. These 1.2 polybutadienes have a polymer chain mainly composed of 1.2 bonds, so they have a relatively low viscosity and excellent fluidity during initial (primary) heating, and contain highly reactive branched vinyl groups in the molecule.
It has good adhesion to other materials, and the secondary heating that follows the primary heating causes a rapid crosslinking reaction in the presence of a crosslinking agent, resulting in a rubber-like elastic body that is extremely easy to mold. However, by adding a certain proportion of diene rubber to it, it is possible to overcome these drawbacks. It is something that can be resolved. The addition ratio of diene rubber is 20 to 100 parts by weight of 1.2 polybutadiene.
If the blending ratio of diene rubber is less than 400 parts by weight, there will be no noticeable modification effect, and if it is in excess, the fluidity and adhesion during molding will decrease, and the molded footwear will deteriorate. The surface of the component becomes rough, loses its luster, and in extreme cases produces saw-like or wavy irregularities, which results in loss of commercial value as a footwear component, and in the finished product, the difference between the main body part 1' and the insert member 2' of the footwear component. It has the disadvantage of causing problems with adhesion. The diene rubber used in the present invention includes, for example, natural rubber, styrene-butadiene rubber, polybutadiene rubber, polyisoprene rubber, etc. Among them, cis-diene rubber that exhibits ideal rubber elasticity is suitable and is suitable for blending fillers. As a result, bending resistance and abrasion resistance can be improved, and low-pressure fluidity, which is important for pressure molding processing, can be improved. Furthermore, these diene rubbers can be used alone or in combination of two or more. Commonly used rubber compounding chemicals used in the present invention include crosslinking agents, crosslinking aids, crosslinking accelerators, fillers, softeners and colorants to improve fluidity during normal rubber plastic processing. Pigment dyes or ultraviolet rays,
A stabilizer for preventing deterioration due to ozone, oxygen, etc. and a foaming agent may be added if necessary. The material prepared as described above is kneaded in a conventional manner using a known device such as a Banbury mixer, a kneading roll, a kneader, etc., and sheeted to provide the main molded material 1 such as an outsole, midsole, or insole. The main molded material 1 has an outsole,
Insert member 2 such as the heel part, heel part, tread part, etc. of midsole, insole, etc. Notch part 1 of an appropriate shape in the molded part
1 is provided. In this invention, the insert member 2 made of foamable unvulcanized rubber has a hardness, a hardness, Abrasion resistance, chemical resistance,
Materials that are different in material or color in terms of physical properties such as anti-slip properties, bending resistance, rebound resilience, and shock absorption properties are used. Therefore, natural rubber, styrene-butadiene rubber, polybutadiene rubber, polyisoprene rubber, nitrile rubber, chloroprene rubber, polyurethane rubber, etc. are the main ingredients, and blowing agents such as nitroso compounds, azo compounds, sulfonyl hydrazides, and other commonly used foaming agents are used. A rubber compounding chemical is added, and like the main molding material 1, it is kneaded and sheeted in a conventional manner using a known device such as a Banbury mixer, a kneading roll, a kneader, etc., and is shaped into a shape corresponding to the shape of the notch 11 of the main molding material 1. It is cut into an appropriate shape. In the second invention, one side of the insert member 2 (the molding surface of the mold 3)
A vulcanized rubber layer 21 is formed on the surface opposite to 30. This vulcanized rubber layer 21 may be formed by laminating a pre-vulcanized rubber sheet on the insert member 2, but it is also possible to form the vulcanized rubber layer 21 by applying a vulcanization accelerator such as a dithiocarbamate type or thiazole type to one side of the insert member 2. Then, one side of the insert member 2 is vulcanized at room temperature.
It is convenient if the insert member 2 and the vulcanized rubber layer 21 are integrally formed. This vulcanized rubber layer 21 may be vulcanized to such an extent that one side of the insert member 2 is not plastically deformed when the main molded material 1 and the insert member 2 are heated and pressurized in the mold 3. Therefore, a semi-vulcanized state of the vulcanized rubber layer is sufficient. The main molded material 1 prepared as described above is
The insert member 2 is set on the molding surface 30 of the mold 3 and the molding surface 301 of the mold 3 corresponding to the notch 11 of the main molding material 1 (in the second invention, the vulcanized rubber layer 21 is molded). Molding surface of mold 3
Set insert member 2 facing 301)
After that, when the main molded material 1 and the insert member 2 are heated and pressurized by a conventional method, the insert member 2 is foamed during the initial heating, and at the same time, the main molded material 1 is plastically deformed. At this time, due to the excellent fluidity and adhesiveness of the 1.2 polybutadiene contained in the main molding material 1, a part of the main molding material 1 is formed into the foamed cells 20 of the insert member at the boundary of the foamed insert member 2. It is penetrated and firmly adhered to the insert member 2. And in the second invention,
Since the vulcanized rubber layer 21 is formed on the surface of the insert member 2 facing the molding surface 301 of the mold, the vulcanized rubber layer 21 is not plastically deformed by heating and pressurizing during molding, and 1.2 Due to the excellent adhesive properties of polybutadiene, it is well adhered to the main molded material 1 at the boundary. Then, vulcanization of the main molded material 1 and the insert member 2 is completed by secondary heating following the initial heating. (Effects of the Invention) The present invention is configured as described above, and the insert member 2 is provided in which a part of the main molding material 1 is simultaneously foamed due to the excellent fluidity and adhesiveness of the main molding material 1 during initial heating. The foamed cells 20 of the insert member are penetrated at the boundary of the insert member 2.
Therefore, it is possible to provide a footwear member that is easy to mold, has good adhesive strength between the molded main body 1' and the insert member 2', and has excellent durability. In addition, the vulcanized rubber layer 21 of the insert member 2 is not plastically deformed by heating and pressurizing during molding, and the main molding material 1 does not flow into the molding section of the insert member 2, or the insert member 2 Since it does not flow into the molded part, a footwear member with a clear boundary between the molded main body 1' and the insert member 2' can be obtained. Example A main molding composition having the composition shown in the attached table was kneaded using a Banbury mixer, sheeted to a thickness of 2 mm,
An insole-like foamable main molding material 1 made of unvulcanized rubber having cutouts 11, 11 in the heel part and the tread part is prepared for cutting, and an insert molding composition having the formulation shown in the attached table is similarly added to the Banbury mixer. The main body is made by kneading and sheeting to a thickness of 2 mm, one side of which is coated with a vulcanization accelerator, zinc ethyl phenyl dithiocarbamate, and a 0.3 mm thick vulcanized rubber layer 21 is integrally molded on only one side. A foamable insert member 2 made of unvulcanized rubber was prepared by cutting the molded material according to the shape of the notches 11, 11. The main molding material 1 prepared in this way is set on the molding surface 30 of the molding die 3, and the insert member 2 is vulcanized onto the molding surface 301 of the molding mold 3 corresponding to the notches 11, 11 of the main molding material 1. After setting the insert member 2 with the rubber layer 21 facing, a separately prepared cloth 4 is set on the main molding material 1 and the insert member 2,
Main molding material 1, insert member 2, and cloth 4 at 150℃.
Heat and pressurize for 8 minutes at a press pressure of 20 kg/cm ² to foam and vulcanize the main molded material 1 and the insert member 2 and integrate them.
By laminating the cloth 4 on top of the shoes, a 6 mm thick insole having insert parts 2' having lower hardness and superior cushioning properties than the main part 1' in the heel part and the stepping part was formed. This insole had the desired effect of the present invention.

【table】

[Table] Hardness determined by compression hardness test according to the relevant Japan Rubber Association standards.

[Brief explanation of drawings]

The drawing shows an embodiment, and is a sectional view of a main part showing a molded state of an insole according to the present invention. Explanation of symbols: 1...Main molded material, 1'...Molded main body, 11...Notch, 2...Insert member, 2'...Molded insert member, 21
... Vulcanized rubber layer, 20 ... Air bubbles, 3 ... Molding mold,
30... Molding surface, 301... Molding surface, 4... Cloth.

Claims (1)

[Claims] 1 The main component is 20 to 400 parts by weight of diene rubber based on 100 parts by weight of 1.2 polybutadiene with a crystallinity of 10 to 40%, and the molding surface 301 of the mold 3
The main molding material 1 made of an unvulcanized rubber dough having a partial notch is placed on the molding surface 30 of the mold 3.
1 and the notch 1 of the main molded material 1.
An insert member 2 made of foamable unvulcanized rubber, which is different from the main molding material 1 and has a vulcanized rubber layer 21 on the surface facing the molding surface 301, is placed on the molding surface 301 of the molding die 3 corresponding to 1. A method for molding a footwear member integrating dissimilar rubber pieces, characterized in that after setting the main molded material 1 and the insert member 2, the main molded material 1 and the insert member 2 are integrated by heating and pressurizing and vulcanized.