DE1685421A1 - Process for the manufacture of footwear with soles made of polyurethane foam - Google Patents

Description

Process for the production of footwear with soles made of polyurethane foam The invention relates to a method for manufacturing footwear with soles made of polyurethane foam. The device that is used to carry out the inventive Method used is one of the usual types, so it includes one Last against which the upper leather is fixed, and one with the casting material filled mold, in which the last is inserted under pressure.

Footwear with soles made of polyurethane foam is generally known its production has so far been carried out with success. However, it has been shown that such soles the expectations placed in them in the case of unfavorable ones Weather conditions are not sufficient, especially with regard to their coloring. The casting conditions ultimately resulted in undesirable material properties a method, so that the present invention is based on the object for the production of footwear with soles made of polyurethane foam in proposal to bring, when it is carried out, the well-known disadvantages no longer exist available. According to the invention is therefore primarily a new polyurethane foam brought forming raw material mixture in proposal and a method for the rest Improvement of the casting conditions, with the starting point for the strips and the casting mold selected material is taken. Another object of the invention can be seen in it, suitable measures with regard to the coloring of such Bring polyurethane foam soles in suggestion.

According to the invention, to solve the tasks set, first suggested the physical properties of the polyurethane foam thereby to improve that a fiber fabric is added to the raw material mixture. This Fiber fabric with good affinity and good adhesive strength for the raw material mixture made of natural and / or synthetic fibers, such as polyester, Nylon, vinyl, rayon, Acetate, silk, cotton or the like., Are made alone or with other raw fibers are added together to the raw material mixture.

In the device for carrying out the method according to the invention According to the invention, the bars and molds used consist of one Material with low dielectric loss and low ultra-high frequency flight ability. This determination according to the invention for the selection of the material takes place with respect to on the inventive casting conditions, which are characterized in that a Ultra high frequency wave inducing electrical heating system for the purpose of injury of the polyurethane foam is used. According to the invention will therefore continue Brought into proposal, either the inner wall of the casting molds with a layer in synthetic resin finely divided powder with large dielectric loss or a synthetic resin skin with the same powder, for example by applying a suitable suction force in constant contact with the inner wall of the casting mold keep.

Another object on which the invention is based is thereby achieved that the inner wall of the casting mold either with a hardness preventing coloring Color of suitable strength is painted, which consists of white dye as the main component and possibly from an ultraviolet absorbent, into a somehow active one Group for reaction with synthetic resin containing 4NCO groups exists, or that the inner wall of the casting mold with a thin skin of high molecular weight Fabric of the desired color, for example by creating a suitable one Suction force is kept in constant contact. In the mold prepared in this way the raw material mixture is then filled, so that after inserting the with the upper leather connected last under pressure, the sole can be cast onto the upper leather.

The raw material mixture for the polyurethane foam generally contains high molecular weight compounds with active hydrogen atoms directly linked to O groups react.

These -NCO groups will hereinafter be briefly referred to as active hydrogen-containing ones Called connections. The raw material mixture for the polyurethane foams contains continue as the main ingredient poly-isocyanate compounds, both compounds are mixed with water, catalysts such as triethylenediamine, N-methylmorpholine, diotyltindilauleate and the like, and emulsifiers such as silicone oil (polydimethylsiloxane), ammonium oleate and the like. like

If a prepolymer compound is used, a linear one is obtained Polymers with N-NCO groups, for example by the reaction of a molar excess polyisocyanate compound with the active hydrogen-containing Compound or dm the same linear polymer, which with the action of the Diaamine like ethyl diamine. Diethylethanolamine and the like is chained, and this mixture is then water and other aids are added.

For the production of the polyurethane foam suitable for shoe soles the selection of active hydrogen containing compounds is paramount important. The active hydrogen-containing compounds suitable according to the invention preferably have a molecular weight of at least 700 and an OH value of around 50 - 200. If these compounds are converted into a prepolymer, then the isocyanate (-NCO) content should preferably be between 4 and 8 ß. as Examples are polyesters that are produced by the esterification of die or polyalcohols, such as ethylene glycol and grimethylpropane and dicarboxylic acids such as adipic and phthalic acid, Polyester amides, which are formed by heat condensation reaction from dicarboxylic acids with amine alcohols such as ethanolamine and diethanolamine, or condensation products of polyalcohols and ethyl diamine or piperazine, and by ring-opening polymerization Polyalkyl ether glycols obtained from ethylene oxides, propylene oxides and the like will.

It is also critical to the present invention Importance of using a suitable crosslinking agent; such a means can for example an active amine such as o-dichlobenzidine, 4, 4'-methylen-nis (2-chloroaniline) and the like, and polyhydroxyl compounds such as 1,4-butanediol.

The polyisocyanate compound used according to the invention is selected from the group which, for example, 1,5-naphthalene diisocyanate, 2,4 and 2,6 tolylenedi-isocyanate and a mixture thereof, 2,4-tolylenedi-isocyanate dimer, 4,4'-diphenylmethane diisocyanate and 4,4 ', 4 "triphenylmethane triisocyanate.

The invention will now be described in more detail below. To improve the physical properties of the polyurethane foam as a sole material, especially to improve the resistance to wear and tear due to friction and tensile strength, the polyurethane foam is reinforced by a Casting process brought into firm connection with fiber fabrics These fiber fabrics are used as a reinforcing agent and therefore those fibers are used that have a sufficient affinity and adhesive strength to the chosen one Have a mixture of raw materials. They can be chosen from the group consisting of polyester, Nylon, vinyl, Contains rayon, acetate, silk, cotton and the like. Other natural or synthetic fibers can be used to form fiber fabrics with these Fibers are mixed. The fiber fabrics form a texture of their strength anisotropic fibers in which the individual raw fibers are felted together are. The selected density of the fiber fabrics is preferably 50-150 g / m2 and the raw fibers are about 2-8 cm long.

For the purpose of preparing the casting process, the Raw material mixture is poured into the mold and it is then a according to the outline form The casting mold cut to size fiber fabric is placed in the casting mold, this Fiber fabric is firmly bound by the polyurethane foam.

Of course, the fiber fabric that has been cut to size can also be used first are placed in the mold before the raw material mixture is then placed in the mold is poured. These fiber fabrics improve the resilience of such soles against abrasion due to friction significantly, by approximately a factor of?, and the tensile strength is thereby improved by approximately a factor of 3, like this can be found in Example 1 set out below.

Cross-linking and foaming combined with polymerization ruptures of the raw material mixture introduced into the mold is achieved in that the mold is heated by buses, whereby precautions must be taken, that the heat generated is not dissipated. With the known Devices for carrying out the process came infrared heaters, electric Banks or electric heaters are used. The invention now starts from the consideration from that such arrangements to ensure a continuous work flow high efficiency are too expensive and that a homogeneous heat treatment of the whole polyurethane foam body to perform in a short time only very difficult is because the foam is heated by thermal conduction over the entire Surface must be done. Accordingly, according to the invention, to avoid this Proposed disadvantages to choose an improved heating system, which ultrahigh frequency wellqn induced stroin used.

According to the invention it is therefore proposed that the molds and to manufacture the strips from a material that has a low dielectric Loss and has a poor ability to swallow compared to ultra-high frequency waves having. It is also proposed that the inner wall of the casting molds with a Layer in synthetic resin finely divided powder to large dielectric loss so that the inner wall of the casting molds when irradiated with ultra-high frequency waves Radiates warmth. It is also possible to make a synthetic resin skin with the same powder, for example by applying a suitable suction force, in constant contact with the inner wall to hold the mold. After the foam and polymerization reactions of the raw material in the clear space between inserted lasts and mold have taken place, the walling of the Casting mold acted upon by ultra-high frequency waves of example 2 2 500 NHz.

In this case, the layer or skin of the finely divided powder containing synthetic resin on the inner wall of the casting mold as a reinforcing agent the surface remain or it can adhere to the surface of the sole be brought so that the sole is covered with a protective skin, the layer or skin can also be removed from the casting mold after the casting process will. The material for the molds and the strips is preferably a selected from the group of synthetic resins, for example polypropylene, Epoxy, silicone and furan resin. The powder with large dielectric loss becomes selected from the following group: iron powder, titanium dioxide, zinc dust, carbon black and Red iron oxide. This powder is either in a synthetic resin like epoxy, Furan and phenolic resin, finely divided, or in a skin made of synthetic resin, such as polyamide and Polyvinyl chloride resin.

As upper leather, natural leather, fabrics made of fibers such as vinyl, rayon, Uses nylon, staple fiber, and cotton and synthetic resin will, without thereby impairing the implementation of the method according to the invention will.

Since it is possible according to the present inventive method, to reach the required heating temperature in a relatively short time, is the implementation of the entire heat treatment to about 1/10 of the usual heat treatment reduced; the individual test data are in the example given below 2 held. Since it is completely sufficient, a fraction of the broadcast Ultra high frequency wave energy to raise the temperature of the powder with great Expend dielectric loss on the inner wall of the casting molds and therefore the polyurethane foam not only because of the ultra-high frequency energy it absorbs but also warmed up by the thermal conductivity over the entire surface T, is therefore the achievable efficiency is extremely high. To hold on is therefore. that the heat treatment is very homogeneous for each part of the polyurethane foam can be done so that the foam is homogeneous and stable physical Has properties.

Because polyurethane foam is generally not weather-resistant and especially not color-fast (polyurethane foam generally discolours) yellowish), it is Sales value of footwear with soles made of such Foam generally very little. Especially to avoid discoloration According to the invention, the following method is therefore proposed for such soles.

Before penetration of the raw material mixture is applied to the inner wall of the casting mold a discoloration-preventing color is applied, the main component of which is a white color Contains dye, which is mixed with other dyes of a desired hue are, all the dye are finely divided in a synthetic resin. For this synthetic resin one such is preferably used, that from the group of synthetic resins The one active group for immediate reaction with -NCO groups was selected have, for example polyamide, polyone ester, polyether and polyacrylic # nitrile resin. The synthetic resin layer formed on the inner wall of the casting mold can therefore with the polyurethane foam react so that the sole is made of polyurethane foam with a layer of this synthetic resin in which various dyes are fine are distributed, is afflicted. Instead of forming a synthetic resin layer on the The inner wall of the mold can also have a skin made of high-molecular substances such as polyamides, Polyvinyl chlorides, polyacrylonitriles, polyester resins and polyurethane rubber, all mixed with the aforementioned dyes or on which a color pattern where appropriate, introduced into the mold in this way that the skin is kept in close contact with the inner wall of the casting mold so that ultimately the skin is made of molecular substances and the sole is made of polyurethane foam covered. Such a skin made from high molecular weight substances can also be placed in the casting mold be introduced with an adhesive layer that reacts with the -NCO group is covered.

Preferably those dyes are selected which are in the group white dyes are included, which are most effective at protecting against exposure to light are; accordingly zinc dust, lithopone and titanium oxide are selected. Is it if you want to produce colored soles, then white dyes will be such of the desired color added. The amount of white dye can thereby decreased exposure to ultraviolet light absorbing agents such as phenyl salicylate Oxybenzophenone and Benzq »hiazole is added.

Among the white dyes mentioned above are titanium oxide and zinc dust those that at the same time produce a substance with high dielectric loss when heated with ultra-high frequency waves induced electricity.

The aforementioned measures serve in their entirety to achieve a undesirable coloring of the soles made of polyurethane foam to Prevent because light is primarily a discoloration of the polyurethane foam brought about, can be shielded. Desired coloring for the soles made of polyurethane foam can on the other hand be achieved by covering the soles with a synthetic resin layer Desired coloring can be afflicted, so that the produced according to the invention Footwear can be customized.

The process according to the invention is described below with the aid of examples explained in more detail: Example 1: Composition of the raw material mixture: polyoxypropylene glycol (Molecular weight 3,000, OH value 56) is obtained by pure opening polymerization of propylene oxide (100 parts), silicone oil (polydimethylsiloxane) (1.5 parts), diethylethanolamine (0.5 part), dibutyltin Dil @ uleate (0.1 part), water (0.4 part), tolylene diisocyanate (36.0 parts) and dichbrobenzidine (12.0 parts).

The molds and the strips to carry out the fun Some devices were made of epoxy resin with a thickness of 20-30 mm on average. The fiber fabric used to reinforce the raw material mixture was made from raw fibers, the caterpillar scand part of polyester fibers from 7 den. Thickness and an average of 5 - 7 cm in length and made from 30 parts of cotton yarn. The fabric was formed into a thin layer with an average density of 135 g / m2. The upper leather consisted of natural leather, which was pulled onto the last. The anti-discoloration paint was made by mixing 100 parts of acrylic resin, 40 parts of zinc dust and 250 parts of a mixed solvent of methyl ethyl ketone and ethyl acetate.

This paint was sprayed onto the inside wall of the casting mold applied. In order to better release the finished product from the casting mold, if necessary also on the inner wall of the casting mold before the paint is sprayed on Adhesion reducing agent can be applied.

The pouring process was now carried out in such a way that after spraying the color on the inner wall of the casting mold with a pre-calculated amount was replenished with the above-mentioned composition of raw materials and finally Fiber fabric cut to size according to the shape of the mold was placed on the raw material mixture. During the first 30 minutes the fibrous web became soaked and soaked up by the mixture of raw materials and during the following 20 min then began with the introduction of the last provided with the upper leather in the mold the foaming reaction, the foaming and polymerization reaction was almost complete 2 1/2 min completed after the raw material mixture was poured in. At this point in time was the device from the outside for 3 min with ultra-high frequency waves of 2450 MHz irradiated by an ultra-high frequency oscillator (3 KW). Through this Heat treatment developed the polyurethane foam heat, causing the crosslinking reaction thereby accelerated. The recorded test conditions enabled Excellent quality footwear is produced. With the same experimental conditions Footwear was also made that prevented discoloration Color dyes were added that were the same color as the upper leather. The results obtained were the same.

In the table below are the physical properties represented by soles containing fiber fabric, according to the method according to the invention, related to soles that do not contain fiber fabric, but which do the same test conditions were carried out.

Test method Sole with sole without fiber fabric Fiber fabric Specific Weight ASTM D792-50 0.25 0.25 50% Modulus (kg / cm2) JISK 6301 17.8 7.0 Tensile Strength (kg / cm2) "25.8 8.4 elongation (§)" 195 170 Versehleiss (volume) ASTM D1242-56 0, 22 0.42 hardness JISK 6301 73 70 Example 2 Composition of the raw material mixture: Prepolymer + 100 parts silicone oil 1.0 part triethylenediamine 0.1 part dibutyltin Dioctoate 0.05 parts water 0.3 parts 1,4-butanediol 12.0 parts + as prepolymer (Molecular weight 1,300, content of -NCO: 5.5%) such is used, its -NCO groups through the reaction of 2 parts of tolylene diisocyanate and one part Polyesters (molecular weight 1000) were prepared, the polyester being made from adipic acid and diethylene glycol was produced.

The casting molds and the strips to carry out the inventive Devices according to the procedure were made of polypropylene resin. A furan resin had been applied to the inner wall of the casting molds Iron powder (300 mesh) contained in finely divided form, in an amount of 25 parts for every 100 parts of resin, the resin layer had a thickness of about 3 mm and served to reinforce the mold.

Before introducing the raw material mixture into the mold during During the casting process, the mold was irradiated with ultra-high frequency light, to make the iron powder radiate heat into the furan resin so that the mold temperature finally reached 750 ° C. That temperature was required to accelerate the foaming and polymerization reactions.

In the experiment carried out, in which a raw material mixture of When the aforementioned composition was used, the foaming reaction was within of 2 minutes after the cream mix was poured into the mold. With These test conditions resulted in footwear of the same quality as when carried out Experiment 1 could be obtained, the only thing that could not be the upper leather was a fabric made of vinylon fibers be used.

The table below shows a comparison of the physical values Properties of shoe soles recorded once after the conventional type of heating produced for example with electrical heaters in metallic molds and on the other hand using ultra-high frequency radiation according to the invention.

Method according to the known method, invention irradiation duration Heating time (2.45 MHz) (1300C) 1 min 2 min 3 min 10 min 20 min 30 min 100% Module (kg / cm2) 9.0 13.1 12.9 8.5 11.5 11.7 Tensile strength (kg / cm2) 19.0 32.3 33.0 16.2 28.0 29.5 Elongation (%) 450 600 560 400 550 530 Example 3: On a skin of Titanium oxide, copper phthalocyanine blue and phenyl salicylate in a ratio of Vinyl chloride 0.2 mm thick containing 50: 10: 0.5 parts was used desired color pattern printed. A thin layer of urethane resin adhesive was applied to the skin applied, the skin was then heated to about 1000C with the help of infrared heaters Heat brought and then placed in the mold. The one between the skin and the Air trapped inside the mold was forced by suction openings penetrating through the wall of the casting mold by means of a vacuum pump removed so that the skin can be brought into close contact with the inner wall could. This process was followed by the process steps according to the example 1 with the exception that the raw material mixture used was such as its composition was described in Example 2.

In the present example the molds and the strips were off Made of silicone resin. Slippers with an individual look could be produced are used when a woven fabric composed of intermingled fibers of nylon and staple fibers became.

Claims (6)

Claims 1. A method for manufacturing footwear with a A sole made of polyurethane foam molded onto the upper leather, d a d u r c h g e k e n n n z e i n e t that the polyurethane foam-forming raw material mixture a fiber fabric with good affinity and adhesive strength to the mixture is added will. 2. The method according to claim 1, d a d u r c h g e k e n n -z e i c h n e t that natural and / or synthetic fibers such as polyester, nylon, Vintlon, Rayon, acetate, silk, cotton and the like, with or without other raw fibers can be used individually or in combination. 3. Method of making footwear with an attached to the upper leather molded sole made of polyurethane foam, d u r c h g e k E n n z e i c h -n e t that the coming to the execution of the procedure in application Molds and strips made of a material with low dielectric loss and low ultra-high frequency wave swallowing ability will be produced that initially the inner wall of the casting molds either finely distributed with a layer in synthetic resin Powder is coated with large dielectric loss or that a synthetic resin skin with the same powder in close proximity with the inner wall of the Casting mold is brought that the raw material mixture is then introduced into the casting mold and the last provided with the upper leather is used and that finally the crosslinking of the polyurethane foam by irradiating the mold from bussen is accelerated with ultra-high frequency waves. 4. The method according to claim 3, d a d u r c h g e k e n n -z e i c h n a t that polypropylene, Epoxy, silicone or furan resin and, as powder added to the synthetic resin, iron powder, Titanium oxide, zinc dust, soot, red iron oxide or the like. is used. Process for the manufacture of footwear with a leather upper molded sole made of polyurethane foam, d u r c h e k It is noted that the inner wall of the casting mold with a skin is more suitable Strength of a discoloration-preventing color from white dye as the main ingredient, mixed with dyes of a desired hue that are in an active group finely divided for direct reaction with synthetic resin containing -NCO groups is, is coated, or the one that is optionally provided with a color pattern thin skin, highly mottled, possibly the aforementioned Dyes containing substance brought into close contact with the inner wall of the casting mold is, or that a thin layer of the same high molecular weight substance with an adhesive layer abandoned for immediate reaction with -NCO groups on the inner wall of the casting mold is that the mold is filled with the raw material mixture and finally the with the upper leather provided last is inserted into the mold. 6. The method according to claim 5 d a d u r e h e k e n n -z e i c h Not that zinc dust, lithopone, titanium oxide and the like as the white color are active Groups for direct reaction with synthetic resin containing -NCO groups, phenol, Polyester, polyether, polyamide and the like resin, and as a rolling stock for the thin skin high molecular weight substance polyamide, polyvinyl chloride, polyacrylonitrile resin, polyurethane rubber and the like is used.