CS271815B1 - Polymer material for footwear parts production - Google Patents

Abstract

The solution concerns the problem of the production of lightweight material for the bottom of shoe parts, designed for extremely light shoes.The goal of the invention is to a prepare lightweight material on the base of ethylene vinyl acetate copolymer with the specific weight of 0.2 to 0.3 g.cm<3> at the hardness Shore A 35 to 50 without the significant decline in physical-mechanical properties, especially scuff-resistance.The introduced goal is achieved by the fact that, as a polymeric component, ethylene vinyl acetate copolymer contains a block polymer of styrene- butadiene-styrene, the so-called thermoplastic elastomer, which contains 33 percent of butadiene and 33 percent of styrene, 34 percent of setting oil in the amount from 20 to 25 percent by weight with the content of 40 to 60 percent by weight of ethylene vinyl acetate copolymer, in which the content of vinyl acetate component forms 12 to 22 percent, and which has a flow index of the melt from 0.3 to 5.0.

Description

The invention relates to a polymeric material for the manufacture of shoe parts, in particular soles, midsoles and wedges, based on a expanded ethylene vinyl acetate copolymer with the addition of a polydiffluent polymer component, further comprising a crosslinking agent, peroxide vulcanization activator, blowing agents, blowing agent decomposers, fillers, pigments and, optionally, paraffin-naphthenic oils, which reduce the proportion of fillers by their proportion.

Lightweight ethylene-vinyl acetate copolymers are used extensively for the manufacture of lightweight footwear parts, in particular for the manufacture of soles, midsoles and wedges, the properties of which are modified by the addition of other polymeric materials such as polyethylene, ethylene-propylene copolymer, polyisoprene or styrene. butadiene copolymer with a high content of styrene component.

However, these materials are no longer suitable for the production of extremely light footwear, since there is a significant deterioration in physico-mechanical parameters, especially in the range of specific gravity from 0.2 to 0.3 g / cm ³ , where the required hardness of 35 to 50 Shore A based on expanded ethylene-vinyl acetate copolymer modified with isoprene or high-styrene rubber, they have their specific gravity limits of 0.28 and 0.25 g / cm ³ , respectively, at the very limit of the physico-mechanical performance in terms of technical applicability.

Therefore, the use of expanded ethylene vinyl acetate copolymers modified, for example, with high-styrene rubber or polyisoprene, remains limited to a specific range of specific weights. However, this restriction does not apply to polymeric material for the manufacture of shoe articles, in particular soles, midsoles and wedges, based on expanded ethylene vinyl acetate copolymer with the addition of a modifying polymer component, further comprising a crosslinker, peroxide vulcanization activator, blowing agents, blowing agent decomposers, fillers, pigments and optionally paraffinic-naphthenic oils, which reduce the aliquot of fillers by their composition according to the invention, characterized in that it contains a linear block copolymer of styrene-butadiene-styrene as a modifying polymer component, i. a thermoplastic elastomer containing 33 wt. % butadiene and 33 wt. styrene 34 wt. % of extender oil in an amount of from 20 to 25 wt. with a content of 40 to 60 wt. % ethylene vinyl acetate copolymer, wherein the vinyl acetate component content is 12 to 22 wt. and having a melt index of from 0.3 to 5.0 g / 10 min.

The advantage of the polymeric material according to the invention is that it can be used in a high degree of lightening, in the range of specific gravity from 0.2 to 0.3 g / cm ^3, while maintaining all the required physico-mechanical parameters at the desired level. disruption. For this reason, shoe parts such as soles, midsoles or wedges made of the material according to the invention can be applied to extremely light footwear, in particular sports shoes and leisure shoes. The shoe soles of the material according to the invention have a hardness of 35 to 50 shore A while having excellent abrasion resistance and reflective elasticity.

The polymeric material for the manufacture of footwear parts, in particular the sole, midsole and wedges, which is characterized by a modification of the ethylene vinyl acetate copolymer with linear block copolymers of the styrene-butadiene-styrene type according to the invention, contains by weight 40% to 60% ethylene vinyl acetate copolymer. % wt. vinyl acetate, with a melt index of 0.3 to 50 g / 10 min; 20 to 25% of a styrene-butadiene-styrene-type linear block copolymer having a 33 wt. styrene, 33 wt. % butadiene and 34 wt. extender oil; 1.0 to 2.5% of a crosslinking agent which is 1,3-bis (tert-butylperoxy-isopropyl) -benzene; 0.2 to 1.0% of a peroxide vulcanization activator which is a trialkyl cyanurate; 1.5 to 2.5% of an azodicarbonamide blowing agent; 2 to 3% of a blowing agent decomposition agent, i.e. zinc oxide, zinc stearate or stearin; 5 to 25% fillers which are calcium carbonate or silica;

0.1 to 1% pigments; and optionally 3.0 to 7.0% paraffinic-naphthenic oils, the addition of which, however, reduces the proportion of fillers.

CS 271815 Bl

The preparation of the material for the manufacture of the shoe parts according to the invention and its processing into the shape of these parts does not differ from conventional processes, in practice it means that the individual components are mixed into the mixture in one or two phases. When working in two phases, all the components, including the blowing agent, are homogenized in the first phase and the peroxide is mixed into the mixture with thorough homogenization in the second phase. The working is carried out in a heated kneader under the condition that the temperature of the mixture must not exceed 120 ° C before the addition of the crosslinker.

The blended polymeric material for the production of the sole parts according to the invention is further processed from the shape of rolls into strips from which the so-called preforms are shaped and then expanded to a finished product in a uniformly heated press, either as plates of the desired size or directly individual shoemaking parts. As already mentioned, and as will also be illustrated in the following examples, shoe parts, in particular soles, midsoles or wedges, of the polymeric material according to the invention have a Shore A hardness value of 35 to 50 and a bulk density of 0.2 to 0.3 g / cm &lt; ³ &gt; and are therefore suitable for mounting in extremely lightweight footwear types, in particular sports shoes and leisure shoes. The following abbreviations are used in the examples:

ITT = melt flow index S = styrene B = butadiene

VAC - vinyl acetate.

Example 1

For the production of lightweight sole plates was prepared material, weight percentages:

containing ethylene-vinyl acetate ITT - 1 g / 10 min (VAC 18%, 48 block copolymer S-B-S linear 20 pigments: iron oxide red 0.1 iron oxide yellow 0.6 asphalt 0.3 titanium white 0.5

Fillers: silica 6.6 calcium carbonate precipitated 17.8 blowing agent azodicarbonamide 1.6 blowing agent decomposition:

Zinc oxide 0.4 Zinc stearate 2.2 Crosslinking agent:

1,3-bis (t-butylperoxy-isopropyl) -benzene 1.9

After processing into sole plates, the following physical properties were measured:

Shore hardness A - 49 Tear resistance Bulk density Dimensional stability Tensile strength Elongation

13.2 kN / m (132 N / cm)

0.28 g.cm ~ 3

2.0% at 70 c, 30 min 2.7 MPa 150%

ITT - melt flow index characterizing molecular weight

Example 2

Material composition for sole plates:

ethylene-vinyl acetate copolymer ITT - 1 g / 10 min (VAC 18%)

3 '

CS 271815 B1 block copolymer SBS linear 17 pigments: carbon black backpack ⁵ fillers: silica 5.2 calcium carbonate precipitate. 16 blowing agent: azodicarbonamide decomposition activator: kioker:

Zinc stearate 2.1 Zinc oxide 0.4 Paraffin-naphthenic oil 3 Crosslinking agent:

1,3-bis (t-butylperoxy-isopropyl) -benzene 1,2 peroxide vulcanization activator triallyl cyanurate 0,5

The material was processed into outsole profiled plates with tread pattern and heel from which the individual outsoles were separated by punching. The following physical properties were measured for the sole material:

Hardness Sh A 46 Tear resistance 13,1 kN / m Bulk density 0,3 g.cm Tensile strength 2,75 MPa Elongation at break 175%

Example 3

The polymeric material for midsole plates was prepared according to the description part of the invention:

ethylene-vinyl acetate copolymer ITT 3 1 g / 10 min (VAC - 12%) 55 block copolymer S-B-S linear 13.5 filler: calcium carbonate precipitated 20.7 pigments: batch colors. 5 titanium dioxide 0,3 blowing agent: azodicarbonamide 1,9 blowing agents (kickers):

zinc oxide 1.5 stearin 0.5 crosslinking agent:

1,3-bis- (tert-butyl-peroxy-isopropyl) benzene 1,6 physical properties:

hardness Sh A 36 tear resistance 11,0 kN / m bulk density 0,28 g.cm tensile strength 2,2 MPa elongation 170%

In all the examples, the lightweight material in the form of a sole or midsole was used to produce extremely light sports or leisure shoes.

Claims (1)

PREVENTION OF THE INVENTION Polymeric material for the manufacture of footwear parts, in particular soles, midsoles and wedges, based on a lightweight ethylene-vinyl acetate copolymer with the addition of a modifying polymer component, further comprising a crosslinking agent, peroxide vulcanization activator, blowing agents, blowing agent decomposers, fillers, pigments Naphthenic oils, which reduce the proportion of fillers, characterized in that the modifying polymer component comprises an oil-set linear block copolymer of styrene-butadiene-styrene of the thermoplastic elastomer type, containing 33 wt. % butadiene and 33 wt. styrene 34 wt. % of extender oil, in an amount based on 20 to 25 wt. at a content of 40 to 60 wt. % ethylene vinyl acetate copolymer, wherein the vinyl acetate component content is 12 to 22 wt. and having a melt index of from 0.3 to 5.0 g / 10 min.