NO142062B - PROCEDURE FOR THE MANUFACTURE OF AN ELASTIC LOST FOAM SHOES FOR ORTHOPEDIC SHOES, SKI BOOTS AND LIKE - Google Patents

Description

The invention relates to a method of manufacture

of an elastic loose lining for special shoes or boots, e.g. for orthopedics or for sporting purposes, such as ski boots, ski boots, after-ski boots or indoor shoes.

Special shoes of the aforementioned type usually have a lining which is either firmly connected to the upper or pushed in as a separate lining. The latter method in particular is preferably used with good boots or shoes and provides an optimal adaptation of the foot to the footwear.

For the production of such inner tubes, various materials have been used up to now, such as e.g. leather, synthetic leather, tek styles or the like, which were padded with cork compounds, poly-urethane plastic foam or the like. A loose f6r thus consists of in-

to 8 individual parts that must be connected to each other by gluing, welding or sewing to get a loose upper with a profiled shape similar to the upper leather. This production is therefore very cumbersome with regard to the necessary machines, personnel and time. There was therefore the task of removing these deficiencies.

With the present invention, these defects are removed,

in that the invention relates to the production of an elastic loose liner for orthopedic footwear, ski boots or the like, which consists of a foam material based on polyethylene or polyethylene mixture polymers, which is preferably partially mesh-formed and predominantly has closed pores. It is therefore high-pressure or low-pressure polyethylene. As comonomers of polyethylene are e.g. suitable vinyl esters, vinyl acetate, vinyl ethers, acrylic acid esters, methacrylic acid esters, acrylonitrile or the like. Such additions in an amount of from 1 to 15% by weight, preferably 4 to 8% by weight, reduce the stiffness of the foam.

The invention therefore relates to a method for producing an elastic loose shoe liner of foam plastic for orthopedic shoes, ski boots and the like, the method being characterized in that from a partially cross-linked foam web with closed pores and on the basis of polyethylene or polyethylene blend polymers, flat cuts for loose shoes are produced.

f6r which is heated to a temperature from approx. 13 0 to 150°C and the thus heated trimmings are shaped using pressure, reps. negative pressure, in a molding press with a concave or convex shape corresponding to the shape of the shoe or with two mold parts to two to the vertical middle section of the outer shoe corresponding to halves of loose shoe fur which, after removal of the steps at the edge, are connected seam-shaped to each other by gluing or welding together .

One can also work in such a way that one inflates in cross-section ring-shaped, tube-like strings of foam materials of the aforementioned type in a preferably multi-part blowing mold, which corresponds to the shape of a shoe while applying heat to a shoe sole.

On these foam sheets or their individual additions

before forming, you can completely or partially, on one or both sides, expandable decorative linings, weaves, artificial leather or the like in a manner known per se.

Example 1

A polyethylene foam sheet with closed pores and med

a volume weight of 30 kg/m and a thickness of 12 mm, produced from high-pressure polyethylene with 1% by weight dicumyl peroxide as a crosslinking agent, 15.1% by weight of azodicarbonamide as a propellant and an amount of 6% by weight of vinyl acetate to reduce the compaction hardness is flame-cased on both sides with a polyamide tricot (trade name nylon) with a longitudinal stretch of 70% and a transverse stretch of 30%

and a weight of 200 g/m . Additional sections of the foam web are then clamped in a vacuum forming machine clamping frame and shaped after heating at approx. 130-150°C in an IR radiation field for half bowls with a thickness of 8-12 mm.

Example 2

A net-formed polyethylene foam with closed pores according to e.g. 1 is lined on one side with a polyamide tricot according to e.g. 1 and on the opposite side with an artificial leather, consisting of PVC coating on a knitted item with a weight of 360 g/m<2>. Additions of this product are heated in a circulating oven with hot air at 170°C

for 15 minutes and then shaped in a press with a positive and a negative tool. This method has compared to the method according to e.g. the advantage that the wall thickness of the molded part can be pressed differently to a predetermined degree and locally.

Example 3

A polyethylene foam according to e.g. 1 is now flameproofed locally with an artificial leather according to e.g. 2 and is shaped in a press corresponding to e.g. 2. The part casing takes place in such a way that the finished loose parts are only given a decorative foil in the upper and later visible part.

According to the production methods stated in the examples, a half of a loose square is produced each time. In total, for the production of a loose pair of molds, four molding tools are required. After so-called erasing of the edges, sewing, they are connected each time to each other suitable halves with each other. The connections take place either by gluing or by welding. As a welding method, hot welding is particularly suitable. Hereby, the edges to be joined of the loose four-and-a-half parts are melted using a sword heated to a temperature of 400°C and then joined together.

The invention shall be explained in more detail with reference to the drawing. Fig. I shows a loose layer consisting of the net-formed polyethylene foam 2, with closed pores, which is lined on the outer and inner side with the expandable foils, weaves, tricots 1 and 3. Fig. II shows a loose layer of net-formed polyethylene foam 4 with closed pores, which are locally covered with a decorative foil. 6 denotes the welding seam and 7 a cover strip, e.g. of artificial leather.

Claims (2)

1. Process for the production of an elastic loose shoe lining of foam plastic for orthopedic shoes, ski boots and the like, characterized in that from a partially cross-linked foam web with closed pores and on the basis of polyethylene or Polyethylene mixture polymers are produced in flat cuts for loose shoes which are heated to a temperature from approx. 130 to 150°C and the thus heated trimmings are shaped using pressure, resp. negative pressure, in a molding press with a concave or convex shape corresponding to the shape of the shoe or with two mold parts to two to the vertical middle section of the outer shoe corresponding to halves of loose shoe linings, which, after removing the steps at the edge, are connected seam-shaped to each other by gluing or welding together. 2. Method for producing a loose shoe lining according to claim 1, characterized in that a strand of the foam material with ring-shaped resp. tube-like cross-section is inflated in a preferably multi-part blow mold that corresponds to the shoe shape during application of heat to a shoe liner.