CN1680091B - Method for making a shoe midsole - Google Patents

Abstract

The invention relates to the technical field of manufacturing methods of shoe products, in particular to a manufacturing method of a middle sole. The technical scheme is as follows: firstly, manufacturing a middle part, secondly, placing the manufactured middle part at the center of a middle sole manufacturing mold, injecting a PU material into a mold space at the periphery of the middle part in an injection molding mode to form an outer edge, and fixedly connecting the outer edge and the middle part into a whole in an injection molding mode; and finally, taking out the manufactured midsole from the mold. The middle part is prepared by foaming the EVA material which is cut and formed. Or the middle part is made by cutting and molding the flattened coir mat. Compared with the prior art, the product obtained by the invention can combine two different materials together, so that the product utilizes respective characteristics, thereby greatly improving the performance of the product and effectively controlling the cost of the product.

Description

Method for making a shoe midsole

Technical field:

The invention relates to the technical field of manufacturing methods of footwear products, in particular to a manufacturing method of midsoles of shoes.

Background technique:

The sole of a general sports shoe consists of two parts: the midsole (also called the middle fork) in the middle layer and the outsole in the bottom layer. Usually the outsole located at the bottom layer is mostly made of wear-resistant rubber material, and the middle layer is mostly made of EVA (commonly known as rubber rubber, its chemical name is ethylene-vinyl acetate, English name Ethylene-Vinyl Acetate,) foam material. This is because the EVA foam material is a polyethylene foam product with a chemical structure containing numerous closed cells, and it is a random polymer compound. In its molecular structure, the substituents are on the molecular chain of the central axis. The arrangement of carbon atoms is irregular, and the configuration of asymmetric carbon atoms in the molecular chain is also different, and the arrangement is irregular, so the crystallinity is small, and the polarity and flexibility are high. Therefore, as a midsole material, it can make sports shoes more comfortable and shock-absorbing. Usually the production method it adopts is to mix and stir a predetermined amount of materials such as EVA (ethylene vinyl acetate), foaming agent and bridging agent, and then heat and foam to become an elastic EVA foam material. For example, the application number is: 96101232.3 Chinese Invention Patent Application Publication, which discloses a kind of "manufacturing method of EVA foam shoe mid-sole and peripheral contour thereof". The main scheme used is: roll the EVA and foaming mixture into a flat offset plate, then cut it to form a reduced shape of the midsole of the shoe, and then place it in a high-temperature mold at 180 degrees Celsius. Foaming becomes the finished shoe midsole, and its side and bottom surface can be formed with embossed pattern or specific arc shape through foam molding. It can be seen from this that it is directly formed through the foaming and expansion of the material in the mold, which reduces the existing process steps of shearing and edging to shape. And it also forms a raised receiving part on the edge of the midsole at the same time, which is used for bonding with the outer slats. This technology has improved the production efficiency of product to a certain extent, but it still has shortcomings. For example, although it directly forms a raised receiving part on the edge of the midsole, because it is formed by an expansion and foaming process, it can be formed by this process when the receiving part has a low degree of protrusion, but when the receiving part When the degree of convexity is high, it cannot be formed by the process of expansion and foaming. Even if it is formed, the strength and other physical properties of the receiving part will be greatly reduced, seriously affecting the quality of the product.

On the other hand, as a thermosetting plastic, PU is also widely used in various fields. The chemical name of PU is polyurethane resin, and the English name is Polyurethane Resin. After hardening treatment, rigid foam can be obtained, which has extremely high compressive strength, good temperature resistance and dimensional stability, and has good air permeability. For example, see the Chinese invention patent No. ZL 92115394.5 Patent specification disclosing a method for preparing open-celled rigid polyurethane foam. In addition, PU can be directly processed by injection molding, so that it can be processed into various shapes according to different needs. Its characteristics also make many shoemakers use it as the material for producing insoles or soles. However, the price of PU is more expensive than EVA, and the direct use of PU material will greatly increase the cost of the product and reduce its market competitiveness.

Invention content:

The purpose of the present invention is to overcome the shortcomings of the current similar products, and provide an economical and practical method for manufacturing shoe midsoles that use different materials and PU materials in combination.

The technical solution adopted in the present invention is: firstly make the middle part, then place the made middle part in the center of the shoe midsole mold, inject PU raw material into the mold space around the middle part by injection molding to form the outer edge, and The injection molding method makes the outer edge and the middle part fixed as a whole; finally, the finished midsole is taken out from the mold.

The above-mentioned middle part is made by foaming the cut and shaped EVA material.

The above-mentioned middle part is made by cutting and forming the flattened coconut palm mat.

The present invention adopts this method to combine materials such as EVA and coconut palm mats with PU materials to make the midsole of shoes, and utilize the high flexibility of EVA and coconut palm mats as the middle part of the midsole of shoes to improve sports performance. Improve the comfort of shoes and enhance the shock absorption effect, and can reduce the cost. At the same time, the plasticity of PU is used to distribute it on the periphery of the midsole to form the outer edge, so that the receiving part formed on the outer edge can be directly injection molded with the outer edge at one time. In addition, even if it is necessary to cut or grind the edge of the midsole during the shoemaking process, it can be done directly, which also takes advantage of the good dimensional stability and strong plasticity of the PU material.

Description of drawings:

Fig. 1 is the schematic diagram of the three-dimensional structure of the shoe middle end produced by the present invention;

Fig. 2 is a front view of the shoe midsole produced by the present invention.

Detailed ways:

The present invention is a production method. Figures 1 and 2 are explanatory diagrams of the products produced by the present invention. The midsole of the shoe involved is composed of two parts, the middle part 1 and the outer edge 2, wherein the middle part 1 can be foamed with EVA The outer edge 2 is made of hardened PU foam material. The outer edge 2 is located on the periphery of the middle part, and is integrally connected with the middle part 1 by means of injection molding. In addition, a receiving portion 21 protrudes upwards from the edge portion of the outer edge 2 , and the receiving portion 21 is injection molded integrally with the outer edge 2 , and transitions to the upper surface of the outer edge 2 in a smooth curve.

The method adopted in the present invention is: firstly, the middle part 1 is made, which is made by foaming the cut and shaped EVA material. For the specific foaming process, please refer to the references in the background technology, which belongs to the prior art. I won't go into details here.

The second is to place the prepared middle part 1 in the center of the shoe midsole mold and fix it, and then inject PU raw materials into the mold space around the middle part 1 by injection molding to form the outer edge 2, so that the outer edge 2 is cooled. Afterwards, it is fixedly connected with the middle part 1 as a whole. The PU raw material described herein is a mixture of polyester polyol and hardener (isocyanurate, isocyanurating can be used). Of course, other catalysts can also be added therein as needed. And the outer edge 2 protrudes upwards to form a receiving portion 21 during injection molding, that is, the receiving portion 21 and the outer edge 2 are integrally injection molded. The protrusion height and the external shape of the receiving portion 21 can be set by the shape of the mold cavity, even if the protrusion height of the receiving portion 21 is relatively high, it can be molded at one time.

In addition, in the process of injection molding, it can also inject certain patterns or other lines or other shapes on the side or other parts of the outer edge 2 by injection molding.

Finally, the finished midsole is taken out from the mould, and at this time the outer edge 2 and the middle part 1 have been fixed as one.

In addition, before injection molding, a small amount of waste tire scraps can be added to the PU mixture, which can not only reduce the usage of PU, reduce the cost of the product, but also be beneficial to environmental protection, so that waste tires can be reused.

Another embodiment of the present invention is that the middle part 1 is made by cutting and forming the flattened coconut palm mat. At present, the coconut palm mat is also an environmentally friendly product with a wide range of use. Using it to make insoles not only has good air permeability, but also And the price is low. The present invention can also use the coconut palm mat as the middle part 1. First, the coconut palm mat is cut and shaped, and secondly, the prepared middle part 1 is placed in the center of the shoe midsole mold and fixed, and then the PU is injected into the mold. Raw materials are injected into the mold space around the middle part 1 to form the outer edge 2, so that the outer edge 2 is solidly connected with the middle part 1 after cooling to form the midsole of the shoe.

The present invention adopts this method to combine materials such as EVA and coconut palm mats with PU materials to make the midsole of shoes, and utilize the higher characteristics of the flexibility of EVA and coconut palm mats as the middle part 1 of the midsole of shoes to improve The comfort and shock absorption effect of sports shoes can be enhanced, and the cost can be reduced. At the same time, utilizing the plasticity of PU, it is distributed on the periphery of the middle part to form the outer edge 2, so that the receiving portion 21 formed on the outer edge 2 can be directly injection molded with the outer edge at one time. In addition, even if it is necessary to cut or grind the edge of the midsole during the shoemaking process, it can be done directly, which also takes advantage of the good dimensional stability and strong plasticity of the PU material.

In a word, the present invention combines the existing two different materials, uses their respective characteristics to greatly improve the performance of the product, and will control the cost of the product.

The above descriptions are only specific embodiments of the present invention, and do not limit the protection scope of the present invention. For example, other similar materials can be used instead of coconut palm mats as the middle part 1 .

Claims (5)

1. the preparation method at the end in the footwear, at first make middle part (1), it is characterized in that: secondly be that the middle part (1) that will make is positioned over the central authorities that make bottom die in the footwear, with injection molding way the PU raw material is injected in the peripheral die space in middle part (1), form outer rim (2), outer rim (2) and middle part (1) are fixed as one in the injection moulding mode; The middle end that to make at last, is by taking out in the mould.

2. the preparation method at the end in a kind of footwear according to claim 1 is characterized in that: middle part (1) is to make after handling through foaming through the EVA material of excision forming.

3. the preparation method at the end in a kind of footwear according to claim 1 is characterized in that: middle part (1) is that the coir fibre mattress through the leveling moulding is made through excision forming.

4. according to the preparation method at the end in claim 2 or the 3 described a kind of footwear, it is characterized in that: described PU raw material comprises the compound of polyester polyalcohol and curing agent, and it forms outer rim (2) through foaming, sclerous reaction in mould.

5. the preparation method at the end in a kind of footwear according to claim 1 is characterized in that: outer rim (2) is when injection moulding, and raising up in its marginal portion forms a carrier (21), and promptly this carrier (21) is an integrated injection molding with outer rim (2).

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