JPS6220802B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing artificial leather shoes with a good appearance, and more specifically, when manufacturing shoes using a leather-like sheet material as an upper, the upper is inserted into a wooden mold, and then a special The present invention relates to a method of manufacturing shoes with a good appearance by heat-setting them with a heater.

Conventionally, sheet products that have a porous and/or non-porous surface layer made of a polymer mainly composed of polyurethane elastomer on a fibrous base material have an appearance and feel that closely resemble natural leather. Therefore, it is widely used as a substitute for natural leather in shoes, bags, school bags, balls, gloves, clothing, etc.
Among these, when leather-like sheets are used for shoes, they have good waterproof properties and can be used even under rainy or snowy weather conditions, and dirt attached to the shoes can be easily removed. It has the advantage of being light and easy to use. However, when manufacturing shoes from such a leather-like sheet material, the leather-like sheet material has a major drawback. This is because the reproducibility of shoe lasts such as toe and feather lines is worse than with natural leather, making it difficult to obtain shoes with good shape. In order to improve this drawback, efforts have been made to change the types of fibers and polymers, or to add other polymers as part of the raw materials, and even to replace leather-like sheets with low melting point polymers or plasticizers. A method of improving heat fixability by using a method such as treatment with an agent, etc., and thereby producing shoes with a good shape has been carried out. However, these methods not only do not sufficiently improve heat setting properties, but also cause a new problem in that low melting point substances melt onto the surface during the heat setting process, impairing the appearance, and are not completely satisfactory methods.

The present inventors investigated a wide range of all processes from the production of leather-like sheets to the production of shoes with regard to the method of producing well-shaped shoes from leather-like sheet products. It was discovered that by using a far-infrared heater for treatment, heat fixability was significantly improved compared to conventional methods, and shoes with good shape similar to natural leather could be obtained.

The leather-like sheet material used in the method of the present invention and the method for manufacturing shoes will be explained in detail below.

First, the leather-like sheet material of the present invention mainly consists of a fibrous base material and a polymer coating layer mainly composed of polyurethane elastomer. The fibrous base material is composed of a fiber aggregate or a fiber aggregate and an elastic polymer impregnated therein. Fiber aggregates are fibers in the form of non-woven fabrics, woven fabrics, knitted fabrics, etc. The fibers used for these are natural fibers such as cotton, linen, wool, rayon, acetate, etc.
Including recycled or semi-synthetic fibers, nylon, polyester, polyacrylonitrile, vinylon,
Examples include singly spun fibers such as polyolefin, mixtures thereof, or composite spun fibers. When mixed spun fibers or composite spun fibers are used, one component constituting the fibers is extracted and removed during the process of manufacturing a leather-like sheet product, or the fibers are divided into their respective components. It is preferable to convert the fibers into ultrafine fiber aggregate fibers or porous array fibers. As the elastic polymer to be impregnated inside the fiber aggregate, any material used for general synthetic leather or artificial leather can be used, such as natural rubber, styrene-butadiene copolymer, acrylonitrile-butadiene, etc. Examples include copolymers, methyl methacrylate-butadiene copolymers, polyvinyl chloride, polyurethane elastomers, other synthetic rubbers, and mixtures thereof. Furthermore, these elastic polymers may be mixed with other polymers. The form in which these elastic polymers are impregnated into the fiber aggregate may be in the form of an emulsion or a solution. In addition, in order to appropriately reduce the rebound elasticity of the leather-like sheet material and give it a texture similar to natural leather, the elastic polymer impregnated into the fiber aggregate must be in a porous state. is preferred.

In the present invention, a porous and/or non-porous surface layer made of a polymer mainly composed of polyurethane elastomer is formed on one or both sides of the fibrous base material. This surface layer corresponds to the silver surface of natural leather, and from the viewpoint of texture, creases, physical properties, etc., a polymer mainly composed of polyurethane elastomer is placed on top of a porous layer composed of a polymer mainly composed of polyurethane elastomer. A multilayer structure with a non-porous surface layer consisting of a composite is preferred. A polymer based on polyurethane elastomer refers to the polyurethane elastomer itself or a mixture of this and other polymers. The polyurethane elastomer contains one or more polymer diols such as polyester diol, polyether diol, polyester, and polyether diol, and one or more organic polyisocyanates, preferably aromatic or aliphatic diisocyanates.
It is mainly polymerized from a chain extender having two active hydrogen atoms, such as a low-molecular diol or a low-molecular diamine. Examples of polymers that can be used in combination with the polyurethane elastomer include polyvinyl chloride, polyvinyl acetate, polymethyl methacrylate, cellulose derivatives, polycarbonate, polyacrylonitrile, natural or synthetic rubber, and the like. In addition, these polymers may contain fillers, colorants,
Various stabilizers and the like may be added. The surface of the leather-like sheet material is optionally embossed as required.

The leather-like sheet material obtained as described above is then cut into a desired shape and size and sewn to be used as the upper of a shoe. These operations on leather-like sheets can be done in the same way as natural leather, but because they are more homogeneous than natural leather, the yield during cutting is better. After sewing, the carapace is fitted into the desired wooden pattern, heat-set, and then the wooden sole is attached and the wooden pattern is cut out. The shape of the shoe is an important condition that determines the commercial value of the shoe, but in order to obtain the desired shape, the heat setting after inserting the wooden mold is good, and as a result, the shape of the wooden mold also remains after the wooden mold is removed. Good reproducibility is required. If the heat setting is poor and the reproducibility of the shoe shape is poor, shrinkage or thinning will occur, and not only will the desired shoe shape not be obtained, but in extreme cases, a drop will occur at the end of the toe cap. Conventional heat-setting treatment is carried out in steam or in air heated by electric heat, etc., but with this method, the temperature of the back side of the leather-like sheet, that is, the floor, rises due to poor heat conduction of the leather-like sheet. Therefore, it had the disadvantage of poor heat setting, that is, poor reproducibility of wooden molds. In addition, in conventional methods, when the heat setting temperature is raised to improve heat setting, the upper skin becomes rough (surface irregularities) and rough, and in severe cases, changes in gloss and color occur.

The present invention uses a far-infrared heater for heat-setting treatment, which completely eliminates the drawbacks of the conventional methods as described above. As the far-infrared heater, far-infrared rays with a wavelength of 1 to 10 μm are effective, and in particular, far infrared rays with a wavelength of 3 to 5 μm are effective.
μ is good. Far-infrared heaters can not only quickly heat the back side of leather-like sheets, but also
Because it has high radiation efficiency and a rapid temperature rise, it can shorten the time required for heat fixation and downsize mechanical equipment, and its low light color temperature makes it effective regardless of the color of the leather-like sheet material. It has the following advantages. It is also possible to use an infrared heater instead of the far-infrared heater, but in this case, the heating efficiency, that is, the heat fixing effect, varies greatly depending on the color of the leather-like sheet material.For example, it is quite effective for black, but it is not effective for white. In addition to the disadvantage that it is almost ineffective, it also has disadvantages such as that it is not efficiently used as heat energy because it is consumed and lost as light energy, and that it easily causes eye fatigue for workers. A far-infrared heater consists of a heating element and a reflecting plate, and it is important in designing this device to combine the two so that radiation is evenly radiated onto the leather-like sheet material.

The present invention will be specifically described below with reference to Examples.

Example 1 A nonwoven fabric made of nylon fibers was impregnated with a polymer solution consisting mainly of ester-based polyurethane elastomer and carbon black added thereto, and the same polymer solution was applied on top of this, and then this was applied to the solvent used for the polymer solution. A porous substrate is created by immersing it in a mixture of water and solidifying it through wet coagulation, then removing the solvent and drying it.
was manufactured. Next, a finishing ink containing the same polymer mainly composed of polyurethane elastomer and carbon black as described above is applied to this porous substrate [ ], and after drying, a rough texture pattern is embossed to form a leather-like sheet material [ ]. I got it. On the other hand, a porous substrate [ ] was produced in exactly the same manner as above except that titanium oxide was used instead of carbon black as the polymer solution, and the same procedure as above was performed except that titanium oxide was used instead of carbon black as the finishing ink. A leather-like sheet material [] was obtained in exactly the same manner.

After cutting and sewing these two types of leather-like sheets to make men's shoes using the uppers,
The toe part of the carapace was placed in a wooden mold so that it would elongate by 15%. Furthermore, these were placed under a far-infrared heater (rated: single phase 200V, 3 heating elements of 2.6KW, peak wavelength 3.5μ) equipped with a reflector so that the surface of the heated object could be evenly radiated. Heat setting was performed for a total of 4 minutes, 1 minute at 120 V and 3 minutes at 120 V. At this time, the surface temperature and back surface temperature of the upper skin are as follows:
are 149℃ and 132℃, while the leather-like sheet material [ ]
The temperatures were 146℃ and 124℃, and after cooling these, they were glued to the outsole, the wooden mold was removed, and the heat fixation rate was measured. As a result, the rate of heat fixation was 61% for the leather-like sheet material [], and 61% for the leather-like sheet material [] was 58%. The heat fixation rate referred to in the present invention is a value obtained by 100 x (length after cutting the wooden mold - original length) / (length after cutting the wooden mold - original length), The length referred to here means the average value of the values obtained by measuring the lengths of the shoe upper in the length direction and the width direction. In this way, both shoes had a high heat fixation rate, so there was no drop at the end of the toe cap, the wooden last was well reproduced, and the shoes were in good shape.

On the other hand, the leather-like sheet material was placed in a wooden mold in the same manner as above, heat-set at 140°C for 15 minutes using the conventional hot air heating method, and then adhered to the outsole and cut out from the wooden mold in the same manner as above. When the heat fixation rate was measured, it was 46% for the leather-like sheet material [ ] and 42% for the leather-like sheet material [ ]. These shoes had lower heat-setting properties than the shoes heat-set with the far-infrared heater, and were thinner, so the drop at the end of the toecap was quite large, and the shape of the shoes was not very good. In addition, shoes using far-infrared heaters had good flatness of the upper and high commercial value, but shoes obtained using the conventional hot air heating method had noticeable moro (irregularities on the surface of the upper) and roughness, and the appearance It wasn't good.

Claims (1)

[Scope of Claims] 1. When manufacturing shoes using a leather-like sheet material consisting of a fibrous base material and a polymer coating layer mainly composed of polyurethane elastomer as an upper, the upper is inserted into a wooden mold and then A method for manufacturing shoes with a good appearance, characterized by performing heat-setting treatment with an infrared heater. 2. The leather-like sheet material is a fibrous base material in which a nonwoven fabric is filled with a polymer mainly composed of porous polyurethane elastomer, a coating layer of a polymer mainly composed of porous polyurethane elastomer, and a non-porous polyurethane elastomer. The manufacturing method according to claim 1, wherein finishing layers of a polymer mainly composed of are laminated in sequence. 3 Claims 1 or 2 that use far infrared rays with a wavelength of 1 to 10μ as a far infrared heater
Fabrication method described in section. 4. The manufacturing method according to any one of claims 1 to 3, wherein the far-infrared heater is a combination of a heating element and a reflecting plate.