Shoe sole made from isobutylene block copolymer

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to the improvement of soles of sports shoes, walking shoes and the like.

【0002】

[Conventional technology]

Generally, a sole is composed of a midsole, an outsole, etc., and each of these soles is provided with the required characteristics of shoes such as lightness, resilience, shock absorbing property, grip property, and abrasion resistance. The sole is made by combining multiple materials to maintain a balance of antinomy characteristics such as resilience, shock cushioning, grip and abrasion resistance.

【0003】

The shock-absorbing property and grip property of the above characteristics are important characteristics for the sole of a shoe. Impact cushioning is an important factor from the viewpoint of reducing the load on the foot when taking off a jump or stopping suddenly.

【0004】

Conventionally, a sponge or gel has been introduced into the sole or a part thereof to improve the shock absorbing property. On the other hand, grip is an important factor from the viewpoint of obtaining propulsive force and preventing falls. Conventionally, a low-hardness elastomer is added to other materials to improve grip. However, the demand for improving shock absorbing properties and grip is further increasing, and new materials for improving performance are required. Further, in order to reduce the burden on the environment in recent years, a recyclable thermoplastic elastomer is also required for the sole material of shoes.

【0005】

[Problems to be Solved by the Invention]

Therefore, an object of the present invention is to provide a sole made of a composition containing a new thermoplastic elastomer material having excellent shock-absorbing property and grip property as a main component.

【0006】

[Means for solving problems]

In order to achieve the above object, as a result of intensive studies, the present inventors have made the main component of the isobutylene block copolymer (a) composed of the isobutylene polymer block and the aromatic vinyl polymer block. The present invention was completed by finding that a shoe sole composed of a composition containing isobutylene-based block copolymer (a) and a rubber-based material (b) as main components has excellent shock-absorbing property and grip property. .. That is, the present invention is a sole characterized by containing an isobutylene block copolymer (a) composed of an isobutylene polymer block and an aromatic vinyl polymer block, and further a rubber material (b). ) Can also be composed of a composition containing.

【0007】

The aromatic vinyl compound unit of the isobutylene block copolymer (a) is preferably at least one selected from the group consisting of styrene, p-methylstyrene, α-methylstyrene and indene. The rubber-based material (b) is natural rubber, styrene-butadiene rubber, ethylene-propylene rubber, styrene-butadiene block copolymer, styrene-isoprene block copolymer, styrene-ethylenebutylene block copolymer, styrene-ethylene propylene. It is preferably at least one selected from the group consisting of block copolymers and ethylene-vinyl acetate copolymers. Furthermore, the present invention can also consist of a resin composition containing an isobutylene-based block copolymer (a), a rubber-based material (b), and a thermoplastic resin (c).

【0008】

The thermoplastic resin (c) is preferably at least one selected from the group consisting of polyolefin-based resins and polystyrene-based resins.

【0009】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail. The sole of the present invention contains an isobutylene-based block copolymer composed of a unit mainly composed of an isobutylene unit and a unit mainly composed of an aromatic vinyl compound unit.

【0010】

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, β-methylstyrene, p-methylstyrene, t-butylstyrene, monochlorostyrene, dichlorostyrene, methoxystyrene, and inden. Among the above compounds, styrene, α-methylstyrene, p-methylstyrene, and indene are preferable from the viewpoint of the balance between cost, physical properties, and productivity, and two or more of them may be selected.

【0011】

As the block copolymer used in the present invention, any block copolymer having any structure can be used as long as it has a unit mainly composed of isobutylene and a unit mainly composed of an aromatic vinyl compound. From the balance of physical properties and ease of synthesis, a triblock body having a structure of (unit mainly composed of aromatic vinyl compound-unit mainly composed of isobutylene-unit mainly composed of aromatic vinyl compound), (isobutylene A diblock body having a structure of a main unit-a unit mainly composed of an aromatic vinyl compound) or a mixture thereof can be used. The ratio of the block copolymer mainly composed of isobutylene to the aromatic vinyl compound is not particularly limited, but from the balance of physical properties, the monomer mainly composed of isobutylene 95 to 20 By weight and aromatic vinyl compound 5 to 80 parts by weight of the monomer mainly composed of aromatic vinyl compound is preferable, and 90 to 60 parts by weight of the monomer mainly composed of isobutylene and aromatic vinyl compound aromatic vinyl compound. The main compound is preferably 10 to 40 parts by weight.

【0012】

The number average molecular weight of the block copolymer is also not particularly limited, but the number average molecular weight of the block copolymer is preferably 30,000 to 500,000, and particularly preferably 50,000 to 400000. When the number average molecular weight is less than 30,000, mechanical properties and the like are not sufficiently exhibited, and when it exceeds 500,000, the moldability and the like are significantly deteriorated. Further, as the rubber material used in the present invention, at least one kind may be selected from general rubber materials such as natural rubber and synthetic rubber. Specific examples of synthetic rubber include isoprene rubber, styrene-butadiene rubber, butyl rubber, butadiene rubber, ethylene-propylene rubber, nitrile rubber, chloroprene rubber, urethane rubber, silicone rubber, acrylic rubber, styrene-butadiene block copolymer, and styrene-. Examples thereof include isoprene block copolymer, styrene-ethylene butylene block copolymer, styrene-ethylene propylene block copolymer, ethylene-vinyl acetate copolymer and the like. Natural rubber, styrene-butadiene rubber, ethylene-propylene rubber, styrene-butadiene block copolymer, styrene-isoprene block copolymer, styrene-ethylene butylene block co-weight from the viewpoint of resilience, abrasion resistance, recyclability, and cost. The group consisting of coalesced, styrene-ethylene propylene block copolymer, and ethylene-vinyl acetate copolymer is preferable. Further, the sole of the present invention may contain a thermoplastic resin and a thermosetting resin, if necessary. Examples of the thermoplastic resin include polyvinyl chloride, polyethylene, polypropylene, polystyrene, nylon, polyurethane and the like. Examples of the thermosetting resin include polyphenols, polyepoxys, polyurethanes and the like. Thermoplastic resin is preferable from the viewpoint of workability. Among the thermoplastic resins, polyolefin-based resins having good compatibility with plasticizers and styrene-based resins whose hardness can be adjusted by addition are particularly preferable.

【0013】

The sole of the present invention preferably contains 5% by weight or more of the isobutylene block copolymer, and more preferably 10% by weight or more. If it is less than 5% by weight, the effect of shock absorbing property and grip property is reduced. Further, the sole of the present invention can be used for both the mid sole and the out sole, and may be the entire sole or a part of the sole such as the treading portion and the heel portion. Further, it may be a non-foaming material or a foam body.

【0014】

If necessary, additives can be added to the sole of the present invention as long as the performance is not impaired. Examples of the additives include stabilizers such as antioxidants and ultraviolet absorbers, lubricants, plasticizers, dyes, pigments, flame retardants, fillers, reinforcing materials, tackifiers, and other auxiliaries.

【0015】

[Example]

Hereinafter, in order to clarify the effect of the present invention, Examples and Comparative Examples are shown. As a comparative example, natural rubber, styrene-butadiene rubber, and styrene-butadiene block copolymers conventionally used for soles were used. A comparative example and a test piece of the composition of the isobutylene block copolymer of the present invention and styrene-butadiene rubber were prepared, and the shock buffering property and the grip property were compared.

【0016】

(Grip property) Friction resistance was determined using a friction tester, and the grip property of each test piece was evaluated.

【0017】

(Impact buffering property) The dynamic viscoelasticity of each test piece was measured, and tan δ (loss coefficient) at 20 ° C was measured. It is known that the larger the tan δ (loss coefficient), the more vibration is absorbed, and it was used as a measure of shock absorption. Furthermore, an iron ball (1 g) was freely dropped on the test piece from a height of 10 cm and collided with the test piece, and the impact absorption was compared from the bounce of the iron ball at that time.

【0018】

[table 1]

<img file="JP2000290331A_D0001.tif" />(Styrene-isobutylene block copolymer synthesis) After replacing the inside of the polymerization vessel of a 500 mL separable flask with nitrogen, 120 mL of n-hexane (dried with molecular sieves) and methylene chloride (with molecular sieves) using a syringe. 80 mL (dried), 0.0876 g (0.38 mmol) of p-dichloromethane) was added. The polymerization vessel was cooled by immersing it in a dry ice / methanol bath at 70 ° C., and then 0.036 g (0.39 mmol) of 2-methylpyridine was added. Next, a Teflon liquid feed tube was connected to a pressure-resistant glass liquefaction sampling tube with a three-way cock containing 33.9 mL (419.9 mmol) of isobutylene monomer, and the isobutylene monomer was fed into the polymerization vessel by nitrogen pressure. Further, 1.50 mL (13.7 mmol) of titanium tetrachloride was added to initiate polymerization. After stirring at the same temperature for 1 hour from the start of polymerization, about 1 mL of the polymerization solution was withdrawn from the polymerization solution for sampling. Subsequently, a mixed solution of 12.15 g (116.7 mmol) of styrene monomer, 12 mL of n-hexane and 8 mL of methylene chloride, which had been cooled to 70 ° C. in advance, was added into the polymerization vessel. Ten minutes after the addition of the mixture, about 10 mL of methanol was added to terminate the reaction.

【0019】

After distilling off the solvent and the like from the reaction solution, the mixture was dissolved in toluene and washed with water twice. Further, a toluene solution was added to a large amount of methanol to precipitate the polymer, and the obtained polymer was vacuum dried at 60 ° C. for 24 hours to obtain a target block copolymer. The molecular weight of the polymer obtained by the gel permeation chromatography (GPC) method was measured. The Mn of the isobutylene polymer before the addition of styrene was 70,000 and the Mw / Mn was 1.16, and the block copolymer after the styrene polymerization had a Mn of 101,000 and a Mw / Mn of 1.40. 20 parts of styrene-butadiene rubber (SBR) was kneaded with 80 parts by weight of the obtained isobutylene block copolymer at 150 ° C, and then press-molded at 150 ° C. (Hardness 50) (Natural rubber) 50 parts of carbon black and 5 parts of vulcanizing agent were kneaded with 100 parts of natural rubber (NR) at 80 ° C, and then press-molded at 150 ° C to obtain vulcanized rubber. (Hardness 60) (Styrene-butadiene rubber) 100 parts of styrene-butadiene rubber (SBR) was kneaded with 50 parts of carbon black and 5 parts of vulcanizing agent at 80 ° C, and then press-molded at 150 ° C to obtain vulcanized rubber. (Hardness 60) (Styrene-butadiene block copolymer) A commercially available styrene-butadiene block copolymer (SBS) (Kraton D1102 ) was press-molded at 150 ° C. (Hardness 65) [0020]

[Table 2]

<img file="JP2000290331A_D0002.tif" />【0021】

[Table 3]

<img file="JP2000290331A_D0003.tif" />From this result, the composition for soles made of the isobutylene block copolymer and the rubber material of the present invention has a larger coefficient of friction (higher grip) and shock absorption than the elastomer usually used for soles. It was confirmed that it was expensive.

【0022】

[Effect of the invention]

As described above, the sole made of the isobutylene block copolymer of the present invention and the rubber material has a high grip property and a high shock absorbing property. When the sole of the present invention is used for the outsole, high grip and high shock-cushioning property can be expected, and when used for the mitt sole, high shock-cushioning property can be expected. Further, since the isobutylene block copolymer of the present invention is a thermoplastic elastomer, it is excellent as a material for recyclable soles without the need for vulcanization.