DE2318013A1 - METHOD FOR MANUFACTURING AN UPHOLSTERY SOLE AND A SHOE WITH SUCH A SOLE - Google Patents

Description

Dip '. U:

> ί ":. I" ·: IT Ί S - '' Π.

298-20.519Ρ (20.52OH)

April 10, 1973

Dr.-Ing. Punck KG, Munich

Method for producing a cushioned sole and a shoe with such a sole

For a long time, a new material for the soling of shoes has acquired a large share of the market. It is foamed polyurethane, which is processed in the reaction casting process. Here two liquid components - namely polyol and isocyanate - are brought together shortly before they are placed in the mold mixed. The sole material polyurethane is then created in the mold through reaction of the two components, whereby a Propellant added to one of the components ensures the formation of a very fine-pored foam.

At first it was believed that the new sole material also contained 298-xl76O-SdBk

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to have found the ideal material for upholstered soles. It was found, however, that the polyurethane foam only has sufficiently good wearing properties for shoe soles if its density is above 0.4. Only above this density its physical values - such as tensile strength, elongation, tear strength and abrasion resistance - are so high, that it is suitable as a sole material. With these mechanical strength values, however, there is a certain hardness of the Foam connected. The Shore hardness "A" of a polyurethane foam which can be used for shoe soles and has a density of more than 0.4 is above 50 and can go up to 75. Such shore hardnesses are, however, below for a highly elastic, soft ball pad the insole, as required for shoes with cushioned soles, is much too high. Such ball pads are usually made of latex foam or vulcanized foam rubber and have shore hardnesses between 20 and 30 a density of 0.2-0.3

This information shows that it is necessary even when using polyurethane foam as the sole material for the known upholstered soles within the sole body primarily in the ball of the foot and in shoes with upholstered soles under the insole of the same, at least in the ball area, a piece of padding made of another soft lightweight foam to arrange. The upholstered soles must therefore be made of two different materials - namely an abrasion-resistant outer material good wearing properties and a soft, elastic inner padding.

With the help of polyurethane foam systems one can easily produce soles by adding a certain amount the mixed liquid components either poured through an opening into a closed sole mold or into the

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allows the open form to flow and then immediately closes the lid of the form. The liquid initially increases only part of the mold cavity and spreads out on all sides on the bottom of the mold. Only starts after a few seconds the foam formation process, whereby in the so-called rise time the mold is completely filled with foam and a certain one Foam pressure is created.

In the production of well-known upholstered soles, the outer sheep is first made in the form of a trough sole from an abrasion-resistant, tough elastic material, such as rubber or soft PVC, in the vulcanization or injection molding process. Then the inside of the trough sole - at least in the ball area - A prefabricated padding made of a soft, lightweight foam is inserted. However, these procedures require several work steps and do not guarantee a firm connection between the cushion insert and the firmer trough sole.

However, manufacturing processes for shoes are also known in which a cushioned sole has been put on beforehand a padding insert on the insole directly with the creation of the trough sole on the upper shoe through vulcanization or the foam formation process, DT-AS 1 100 504. By rubber vulcanization or foaming The pressure generated in the mold, which can be up to approx. 8 atm in this process, is, however, below the insole arranged soft foam padding very strongly compressed and its pores with the tough elastic sole material partially filled, so that its elasticity is reduced and the ventilation effect of the sole is less. Through the The high compression of the soft cushioned insert during the formation of the outsole is the one that takes effect after demoulding The restoring force of the cushioning material with a stable insole bulges the outsole outwards. However, the insole is flexible compared to the outsole, then there is a

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Bulge inside the shoe. Both effects adversely affect the load-bearing capacity of the finished cushioned shoe. About that In addition, the high compressibility of the soft foam padding prevents it the formation of a real trough bottom with a relatively large trough interior to a fraction of its original strength from the outer sole material, which considerably increases the load-bearing capacity that is characteristic of upholstered soles worsened.

The object of the invention is to show a method for producing a cushioned sole in which the soft, elastic cushioned insert is on all sides except on its surface is firmly enclosed by the outsole material without it excessive compression and subsequent expansion of the soft, elastic padding insert.

According to the invention, this object is achieved in that the foam pressure of the reaction mixture by selection Dzw. Setting the appropriate compression behavior of the foam system is kept so low that the padding During the foam formation process the outsole does not compress or compresses it only insignificantly.

The procedure here can advantageously be such that the density of a reaction foam foamed in the open air and its density after foaming in the mold is matched to the density and elasticity of the soft, elastic padding insert will. To achieve the aim of the invention, however, there are also various other options, since the Adjustment of polyurethane foam systems can take place extremely varied.

As an example of the particularly advantageous possibility of setting the compression behavior mentioned

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the following values are called: The density of a soft elastic The material used for the padding is at optimal wearing properties approx. 0.2 - 0.3 and its shore hardness "A" 20 - 30. The density of a foamed outdoors Reaction foam for the outsole material should be 0.4 at 0.3 lie. The amount of water required for each to be foamed with the outsoles ^ foam material Cavity chosen so that after completion of the foaming process there is a density of 0.6-0.73 of the sole foam material results. This compression corresponds to an always reproducible foam pressure in the mold before hardening of approx. 1-2 atmospheres. By matching the poured amount to the cavity to be foamed in connection with the density of a free foamed outsole foam and the '' form-foamed * Density compared to the elasticity and density of the padding of the ball of the foot can be caused by the pressure in the Form can be set so that there are none or only /.u a minimal compression of the soft elastic padding insert comes and that the pores of this insert only in the outermost Edge area to be filled with the reaction foam, whereby a good adhesion but no impairment of the cushion elasticity is achieved.

Compared to the known manufacturing process, the inventive the advantage that with the production of the outer shell, the piece of upholstery is cast in firmly adhering to the same that it no longer has to be inserted afterwards. Furthermore, the construction of the molds is significantly simplified because the Padding piece forms its cavity in the sole body itself and cavity-forming approaches on the mold cover no longer exist must be. Since there is only an extremely slight deformation of the cushioning material due to the foam pressure, the wall thickness of the outer shell can also be well determined and the restoring force of the cushion insert

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Internal and external effects do not occur. Due to a special design and shape of the upholstery piece the trough bottom can also be given a special cross-sectional shape. For example, the upper fastening edge of the The sole can be widened by a piece of padding that tapers towards the top.

The cushioning insert can be attached in a simple manner with a pressure-sensitive adhesive, which acts as a permanent pressure-sensitive adhesive layer can be applied to the lid of the mold.

According to the invention, shoes can also be provided directly with a cushioned sole, without this being previously as separate component must be produced. For this purpose, the soft, elastic padding insert is placed on the underside of the upper shoe attached and the upper shoe with the cushion insert as the upper end in the known V / iron inserted into the sole shape. After the mold has been closed, the cavities formed are cast with a reaction foam, according to the invention the foam pressure of the reaction foam mixture by selecting the appropriate compression ratios of the foam system is kept so low that the padding under the insole of the upper is not or only compresses insignificantly. Due to its good flowability, the reaction foam mixture spreads on all sides in the mold during the foaming process, the surfaces of the cushioned insert protruding into the mold are fixed on all sides, however, can be enclosed without substantial compression.

The following are exemplary embodiments of the invention explained in more detail with reference to the drawing. Show it:

1 shows an upholstered sole formed in a mold according to the invention in longitudinal section,

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Pig. 2 one in a sole shape directly to one Ooerschuh on / shaped cushioned sole in longitudinal section.

The cushioned sole shown in Fig. 1 has a padding pad 4 made of a soft elastic material, which is attached to the lid 13 of the mold by a suitable adhesive before foaming. After closing the mold by placing the lid IJ AiAF the ^p ormboden -2 creates a cavity that is filled by a casting nozzle 8 with the thin liquid reaction mixture foam. Before the actual foaming process, the mixture is distributed on the bottom of the mold cavity, so that after foaming an outsole 9 ', which is largely uniform in structure, is created. As shown, the cushion insert 4 can be tapered upwards at 15, so that after the foaming process a widened fastening edge of the trough sole is formed, through which a larger-area and thus more durable connection to the overshoe is created.

a /
In Fig. 2 is an overshoe pulled up on a last 1

shown, a piece of padding on the insole J in the ball area 4- made of soft elastic material before forming the Foam sole is attached. From the upholstery piece 4 through a gap There is also a separate section on the insole that extends into the heel area in reaching joint piece 10 attached, which improves the wearing properties of the shoe. A heel filler 11 is located in the heel area below the joint piece 3 0. The shoe prepared in this way is used as an upper end in a Outsole form consisting of side parts 5 and headstamp 6 inserted, the free cavity of which is then inserted by means of a pouring nozzle 8 is filled via a runner 7. After · filling and distributing the reaction foam mixture on the bottom of the mold and, after foaming, the finished shoe can be removed from the mold be taken out.

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Claims (4)

- 8 claims 1. Process <ur production of upholstered soles, in which one Prefabricated ball pad insert made of a soft lightweight foam attached to the underside of the lid of a sole mold and then the cavity remaining after the mold has been closed is filled with a reaction foam, which encloses and embeds the cushion insert during the formation process of the outsole, characterized in that, that the foam pressure of the reaction. foam mixture by selecting the appropriate compression behavior of the foam system that forms is kept so low is that the padding is not or only slightly compressed will. 2. The method according to claim], characterized in that the Density of the freely foamed reaction foam and the density of the same reaction foam foamed in the sole shape is matched to the specified density and elasticity of the cushion insert. j5. Make the method of claims 1 and 2 made upholstery sole, characterized in that the wall shape of the trough sole is constructive due to a special shape of the padding piece is designed. 4. A method for producing a shoe with a cushioned sole, in which an upper shoe pulled on a last with a cushioning insert made of soft lightweight foam on its underside as an upper end in a sole shape and the cavities remaining after closing the mold are poured out with a reaction foam, which when foaming a enters into a firm connection with the edge parts of the upper shoe and encloses the cushioning insert on all sides, d a d u r c h 409844/0035 characterized in that the foam pressure of the Reaction foam mixture by adjusting the compression Behavior of the foam system kept so low becomes that the upholstery insert is not or only insignificantly is squeezed. 409844/0035