DD280898A1 - TWO-PIECE SHOE OIL FROM MIXED POLYMERS OF THE ETHENS - Google Patents

Abstract

Thermoplastic two-layer shoe sole consisting of a combination of sole materials based on metal alkoxide-modified ethene-vinyl acetate copolymers (EVAC), which are directly formable by injection molding. The sole should be characterized by low density, low weight and low abrasion. The task is to ensure a very good adhesion between the midsole and outsole. The invention is characterized in that the foamed midsole to 97.4 to 98.5 wt .-% of a modified ethene-vinyl acetate copolymer having a melt index of 1.0 to 40 gmin 1 at a temperature of 463 K and a load of 2.16 kp, a vinyl acetate content of 10 to 25% by weight and a vinyl alcohol content of 0.5 to 8% by weight and the outsole to 50 to 80% by mass of a modified ethene-vinyl acetate copolymer having a Melt index of 0.5 to 6.0 g 10 min 1 measured at a temperature of 463 K and a load of 2.16 kp, a vinyl acetate content of 18 to 30 wt .-% and a vinyl alcohol content of 0.5 to 3.0 Ma .-% consists.

Description

Field of application of the invention

The invention relates to a combination of thermoplastic materials based on modified ethene-vinyl acetate copolymers which are directly formable by means of injection molding on prefabricated shoe stocks as sole materials.

Characteristic of the known state of the art

It is known to directly mold shoe soles of thermoplastic materials by means of suitable devices to prefabricated shoe shafts by injection molding. Here are the starting material for the most part Polyvinylchloridweich formulations, called PVC soft formulations below, also used as propellant-containing modification. Both single-layered and two-layered soles (shoe bottoms) are produced. In two-ply soles, in addition to the possibility of a multi-colored design of the advantage of a thin, abrasion-resistant outsole as the first layer with a treibmittolhaUigen and thus light soft midsole as zwoite layer to combine a flexible shoe bottom. So produced footwear has due to the density of the PVC-soft formulation of 1.2 to 1.3g · cm " ³ and the propellant-soft PVC-soft formulation of 0.8 to 0.9 g · cm ³ is still high To reduce the same, the incorporation of modifier types in PVC high polymer blends is proposed in "Plaste und Kautschuk", Leipzig 32 (1985) 9, p.332-333. Preferably, the modifier P (55 EVAC-15-g-45 VC) is used in conjunction with soft PVC formulations for shoe bottom manufacturing. Due to a bulk density of 1.1 g · cm ³ , the abrasion of 100 ^l ) is 150 mm ³ and the Shore A hardness of 60 to 70U, the PVC soft-formulation / modifier mixture is in the property pattern between conventional PVC soft formulations and thermoplastic rubber materials. Even by the addition of propellant sole densities of 0.7g · cm ^{3 are} not exceeded, se that still a high sole composition remains. On the other hand, can be achieved in the processing of thermoset polyurethanes by injection molding material densities of 0.4 to 0.5 g cm ³ . A reduction in density over PVC-soft formulations is achieved by the use of ethene-vinyl acetate copolymer, hereinafter referred to as EVAC, within the group of thermoplastics. In this case) is 2 to 0.96 g cm ³ and using a blowing agent of 0.5 to 0.7 g cm ³ can be achieved both in one and in two-color injection molding shoe bottoms material densities of O.!. However, soles made in this way have a high resistance to abrasion and low strength. An improvement of the mechanical properties while maintaining the thermoplasticity was achieved by modification of EVAC by means of alcohol-containing metal alcoholates was demonstrated in DD-WP 209341. The sole materials used here are modified EVAC having a melt index according to TGL 20 996 of 0.5 to 50 g for 10 minutes, preferably between 1.0 and 20 g.10 min. Compared with the modified EVAC, which may have a vinyl acetate content of 15 to 45% by mass, the modified products have a 2 to 35% lower content of vinyl acetate. This proportion of ester groups isl substituted by hydroxyl groups. The modified EVAC can be used in pure form or in admixture with dyes or color pigments, plasticizers, fillers and lubricants. However, it is also possible to formulate the modified cVAC i> i in a manner known per se such that foamable masses which can likewise be processed by injection molding are obtained.

According to this method, shoe bottoms with comparatively high Shore A hardness values of 72 to 86 U are obtained. In addition, only the production of test plates and molded soles of a component or color are described.

Object of the invention

The aim of the invention is to produce a ^r of two Mischpolyme s of ethene different to composition combined shoe bottom, which has a very low E ^ & iigewicht and in which in addition to good mechanical physical properties especially high adhesive strengths Fuei the composites outsole / midsole and Zwiscnensohle / shaft to be obtained.

Explanation of the invention

The invention has for its object to provide a two-layer shoe bottom, consisting of running and midsole, are used for the individual layers müdiiizie> he Ethy-Vinyiacetat copolymers of different chemical composition and different characteristic levels.

According to the invention the object is achieved by the foamed midsole from a formulation of 97.4 to 98.5 Ma. % of a modified ethene-vinyl acetate copolymer having a melt index of 1.0 to 40g 10min ^-1 , measured at a temperature of 463K and a load of 2.16kp, a vinyl acetate content of 10 to 25% by weight, a vinyl alcohol content of 0 , 5 to 8.0 Ma .-% and 0.2 to 0.5 Ma .-% of a dye, 0.5 to 1.0 Ma .-% of a blowing agent, 0.5 to 1.0 Ma .-% of a foaming catalyst and 0, From 01 to 0.1% by weight of a nucleating agent and the outsole from 50 to 80% by weight of a modified ethene-vinyl acetate copolymer having a melt index of 0.5 to 6.0g x 10min * 'measured at a temperature of 463K and a load of 2.16kp, a vinyl acetate content of 18 to 30 Ma.% and a vinyl alcohol content of 0.5 to 3.0 Ma%, 15 to 45 Ma% of a plasticizer and 1.0 to 10.0 Ma. % of a filler or several fillers, 0.2 to 1.0% by mass of a dyestuff and, if appropriate, from 0.1 to 0.5% by mass of a lubricant, while the processing temperature of the run is Ohlenmaterials 165 to 195X and the midsole material 150 to 190 ° C.

embodiment

From a multi-station soling machine for thermoplastic with two injection units and 12 tool carriers is used as a midsole material a mixture of

98% by weight of a modified ethene-vinyl acetate copolymer having a melt index according to TGL 20966 of 10.1 g.10 min ^-1 , measured at a temperature of 463 kg of a load of 2.16 kg, a vinyl acetate content of 20.1 μm. % and a vinyl alcohol content of 1.5Ma .-%

- 0.35Ma .-% titanium dioxide

- 1.0Ma .-% azodicarbonamide

- 0.60Ma .-% kicker as well

0.05Ma% of fumed silica

and as outsole material a mixture of

70% by mass of a modified ethene-vinyl acetate copolymer having a melt index according to TGL 20966 of 2.9 g.10 min., Measured at a temperature of 4'33 K and a load of 2.16 kg, a vinyl acetate content of 28 Ma.- % and a vinyl alcohol content of 2.5Ma .-%

25% by weight of dioctyl phthalate

- 4.2% by weight of chalk

- 0.3Ma .-% pigment "coral" as well

- 0.5Ma .-% stearic acid

processed under the following conditions:

Table 1

parameter Unit of measurement Injection unit I Spritzeinheitll -Laufsohle- - midsole - temperature C 1st heating zone 175 170 2nd heating zone 185 180 3rd heating zone 190 185 4th heating zone (nozzle) 190 185 backpressure MPa 0 14 injection pressure MPa 14 28 Tool kN 70 70 clamping force

The determined characteristic values of the shoe soles or casual shoes produced according to the invention are contained in Table 2 in comparison to conventionally produced casual shoes with PVC sole.

Table 2

characteristic value Unit of measurement TGL Inventions conven- gem. shoe lerSchuh Shore A hardness HE 14365 60 ... 70 50 ... 60 the outsole Abrasion of the barrel mm ³ 24924 100 ... 150 200 sole Sohlenhaftfestig N-crrr ¹ 15-1207 / 01 Separation is 50 ... 55 of the intermediate practically sole on the shaft Not (Suede) possible Sohlenhaftfestig N-cm ' 15-1207 / 01 Separation is 50 ... 65 of the intermediate practically sole at the Not outsole possible Density of like " ³ 0,94 ... 0,96 1.22 ... 1.35 outsole Density of according to ³ 0.5 ... 0.6 0.81 ... 0.93 midsole Mass of Ver G 210 250 collar sole for the pattern size 42

Claims (1)

Claim: Two-layer shoe sole made of copolymers of ethene, characterized in that the foamed midsole consists of a formulation of 97.4 to 98.5% by weight of modified ethene-vinyl acetate copolymers having a melt index of 1.0 to 40 g.10 min ^-1 , measured at a temperature of 463 K and a load of 2.16 kg Vinyl acetate content of 10 to 25 mass% and a vinyl alcohol content of 0.5 to 8 mass% - 0.2 to 0.5 Ma .-% of a dye 0.5 to 1.0 Ma .-% of a blowing agent 0.5 to 1.0% by mass of a foaming catalyst, as well as 0.01 to 0.1% by weight of a nucleating agent
is made and the outsole of a mixture of From 50 to 80% by mass of a modified ethene-vinyl acetate copolymer having a melt index of 0.5 to 6.0 gmin ^-1 , measured at a temperature of 463 K and a load of 2.16 kp, of a vinyl acetate content of 18 to 30 Ma .-% and a vinyl alcohol content of 0.5 to 3.0Ma .-% - 15 to 45% by weight of a plasticizer 1.0 to 10.0 Ma .-% of one or more fillers - 0.2 to 1.0 wt .-% of a dye and optionally 0.1 to 0.5% by weight of a lubricant
consists.