JPS60215875A - Leather-like material and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a leather-like material having close resemblance to natural leather in appearance and feeling, by mixing crushed natural leather with a thermoplastic resin composed of a PVC resin having a polymerization degree of higher than a specific level and a polyurethane resin having a flow point of within a specific range. CONSTITUTION:A fibrous crushed material having a length of about 0.1-2mm. and obtained by the crushing and disintegration of natural leather is dried to a water-content of <=6wt%, and is mixed with a thermoplastic resin composed of (A) a PVC resin having an average polymerization degree of >=2,000 and a flow point of preferably 130-160 deg.C and (B) a polyurethane resin, under heating at 160-200 deg.C, and pelletizing or forming to a sheet. The amounts of the crushed leather and the thermoplastic resin are 20-60wt% and 40-80wt%, respectively, and the difference between the flow point of the polyurethane and that of the PVC resin is + or -30 deg.C. The product has close resemblance to natural leather, can be handled similar to natural leather, and can be formed easily to shoes, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a leather-like material and a method for producing the same, and more specifically, a relatively hard leather-like material in which crushed natural leather and a thermoplastic resin are mixed and integrated, and a method for producing the same. It is related to.

Natural leather is widely used for bags, shoes, and various decorative items due to its unique properties such as appearance, feel, and toughness.However, due to resource constraints, the cost of secondary products is high, and quality is also high. There is a problem that uniformity cannot be obtained. Therefore, various artificial leathers and synthetic leathers have been developed and widely used as substitutes for natural leather, but although conventional products can approximate some of the properties of natural leather, they have poor overall properties, especially appearance, feel, and breathability. No substitute has yet been found that has the strength and toughness inherent to natural leather. For example, it is well known that polyurethane resin is used as synthetic leather for the soles of shoes that require particularly toughness and abrasion resistance, but this type of synthetic leather is not easy to process by cutting. Therefore, it had to be made as a molded product using IFiJ, and could not be used as a handmade material by shoemakers.

In order to approximate the appearance, feel and breathability of natural leather, a method is already known in which natural leather waste is bound with a thermoplastic resin binder. For example, a method of defibrating leather and adding a thermoplastic binder to the obtained leather fibers to form a sheet (Japanese Patent Application Laid-Open No. 57-14956 (3), natural leather powder and heat-fusible porous adhesive powder) A powder mixture with a powdery substance is applied onto the base material, and then passed through a heated pressure roll to be integrated to form a leather powder coating '!Ji layer.A thermoplastic resin liquid is applied onto this coating layer and dried. A method of pressure treatment after treatment (
There is a Special Publication No. 58-30920>. However, these methods mainly focus on improving appearance, feel, breathability, etc., and the thermoplastic resins used in these methods are only used primarily for their adhesive effects. It is something. Therefore, in order to obtain strength, it is necessary to have a multilayer structure using a base material such as woven fabric or nonwoven fabric, which has the disadvantage that the manufacturing process becomes complicated.

Therefore, the present inventors targeted a relatively sandy leather-like material used for belts, the soles of shoes, the soles of sandals, etc., and developed a material that approximates natural leather in appearance, feel, breathability, and other properties. With the aim of providing a leather-like material that is strong and can also be supplied as a molding material for pellets, etc., as a result of intensive research, we have developed a thermoplastic resin that can be mixed and integrated with crushed natural leather. It has been discovered that this object can be achieved by using a polyvinyl chloride resin having an average degree of polymerization of 2000 or more and a polyurethane resin having a flow 111I temperature within ±30°C of the flow temperature of the polyvinyl chloride resin. This led to the invention.

The leather-like material of the present invention is a leather-like material in which crushed natural leather and a thermoplastic resin are mixed and integrated, and the thermoplastic resin is a polyvinyl chloride resin with an average degree of polymerization of 2000 or more, It is characterized in that a polyurethane resin having a flow temperature within ±30° C. of the flow temperature of the vinyl resin is used.

In addition, the method for producing a leather-like material of the present invention uses crushed natural leather dried to a moisture content of 6% by weight or less, and an average polymerization degree of 20%.
The leather-like material is produced by stirring and mixing a polyvinyl chloride resin with a flow temperature of 130 to 160 °C and a polyurethane resin with a flow temperature of 130 to 160 °C at a temperature of 160 to 200 °C. .

The present invention will be specifically explained below.

The natural leather products used in the present invention are natural leathers such as cowhide, horsehide, pigskin, sheepskin, etc., which are crushed and defibrated using a well-known crusher to obtain a pulverized fibrous material of about 0.1 to 2 mm. It is something. Tanned leathers such as chrome leather and astringent leather are preferred;
It is possible to utilize the cutting waste generated in large quantities in the leather industry. The pulverized natural leather used in the present invention needs to be dried so that the moisture content is 6% by weight or less before mixing with the thermoplastic resin. If the moisture content is higher than this, the moisture contained in the mixture will evaporate when it is heated and compressed into a plate or the like after being mixed with a thermoplastic resin, causing unevenness in the product. Drying is usually carried out at a temperature of 80 to 150°C, preferably 80 to 120°C. This crushed natural leather is 2 of the leather-like materials in the product.
The content is preferably within the range of 0 to 60% by weight, and 3
The most preferred content is in the range of 5 to 45% by weight. If the content is too low, properties similar to natural leather, such as appearance, feel, and breathability, will no longer exist, and if the content is too high, the toughness will be lost and the leather will have creases and break easily.

It is necessary to use a polyvinyl chloride resin having a high degree of polymerization, with an average degree of polymerization of 2000 or more, and the desired product cannot be obtained using conventional general-purpose polyvinyl chloride resins. This polyvinyl chloride resin contains a plasticizer like general-purpose products, and usually contains 40 to 120 parts of plasticizer per 100 parts of polyvinyl chloride.

Diocdylphthalate (DOP) is commonly used as a plasticizer.

This polyvinyl chloride resin preferably has a flow temperature (melting point) of 130 to 160°C under the following measurement conditions.

[Flow temperature measurement conditions Measuring device: Koka type flow tester nozzle: 1 mmφ x 10 mm Load: 100 kg/cm2 Temperature increase rate = 3°C/min Various types of polyurethane resin can be used, but the flow temperature is as described above. It must be within the flow temperature range of 130°C of the polyvinyl chloride resin. If the flow temperature of the polyvinyl chloride resin and the flow temperature of the polyurethane resin differ more than this, the mixed state of these materials, including the crushed natural leather, will not be uniform, and the physical properties of the obtained leather-like material will be uneven, so this is not preferred. do not have. The flow temperature of the polyurethane resin is also preferably 130 to 160°C.

The ratio of polyvinyl chloride resin and polyurethane resin in the thermoplastic resin is 20 to 30% by weight for the former and 70 to 80% for the latter.
Weight%. Too much polyvinyl chloride resin makes it too soft, and too much polyurethane resin makes it too hard, which is not preferable.

In addition to the above-mentioned materials, it is preferable to add a coloring agent, a stabilizer, etc. to the leather-like material of the present invention. For example, Ti(h) can be used as the colorant and Zr1O can be used as the stabilizer.

To explain in detail the method for manufacturing the leather-like material of the present invention, first, natural leather is crushed or defibrated into fibers of about 0.1 to 2 mm using a commonly used crusher, and then Dry at a temperature of 150°C, preferably 80-120°C, until the water content is 6% by weight or less. Next, this dried pulverized natural leather was put into a mixing tank equipped with stirring blades together with the polyvinyl chloride resin and the polyurethane resin, and 1
Stir and mix while heating to 60-200°C. In addition,
This mixing may be performed by roll mixing using a mixing roll or the like.

When the leather-like material according to the present invention is supplied as pellets, after the stirring and mixing described above, the materials may be introduced into a pelletizer in a fluidized state and pelletized.

By using these pellets, molded products of various shapes can be manufactured using extrusion molding, injection molding, etc. In addition, in the case of supplying the material in the form of a plate, it can be formed into the desired plate material using a roll member such as a mixing roll or a calender roll, or it can be directly formed into a plate material by extrusion molding. After these plates are molded, simply by subjecting them to heat press treatment, a leather-like plate with a surface appearance and feel similar to natural leather can be obtained.

Next, examples of the present invention will be shown.

[Example 1] A pulverized natural leather obtained by crushing and defibrating cowhide into fibers of 0.1 to 2 mm was dried at 100°C to a moisture content of 6 wt ω% or less, and 40 parts by weight of this dried pulverized natural leather, Average degree of polymerization 2000
The above polyvinyl chloride resin (plasticizer (dioctyl tstarate) 40 to 12 parts by weight per 100 parts by weight of polyvinyl chloride)
Includes 0 Felony Division. 15 parts by weight of polyurethane resin (flowing temperature 130-160°C)
40 parts by weight, 23 parts by weight of Ti as a coloring agent, and 1 part of LrZn 02mff as a stabilizer were stirred and mixed in a mixing tank equipped with stirring blades in a temperature range of 160 to 200°C.

The obtained fluid mixture was further O-mixed using a mixing roll, and then passed through a calender roll to form a plate material.

This was heat pressed at 130°C to produce a product.

In addition, the polyvinyl chloride resin used was manufactured by Shin-Etsu Chemical Co., Ltd. under the trade name TK-2000 and TK-25.
001STK-25001 (, TK~250OR, T
K-2500W, JIS K-672? The average degree of polymerization measured at 2000.2250.2450.
3800.4500.

In addition, the polyurethane resin used was PANDEXT-5880, a product manufactured by Dainippon Ink and Chemicals Co., Ltd.
They are T-5,875, T-5870, and T-5860.

The leather-like material obtained by this method has an appearance and feel similar to natural leather, regardless of the raw material used, and
As a result of bending test (ASTM D1052), 5
It was able to withstand tens of thousands of bending cycles. 0.4m
It is impossible to tear it with bare hands when it is formed to a thickness of m, but it is easy to cut with scissors, so shoemakers can handle it in the same way as natural leather when manufacturing shoes. .

[Comparative Example 1] A general-purpose polyvinyl chloride resin manufactured by Shin-Etsu Chemical Co., Ltd. under the trade name TK=1300 (average degree of polymerization 1300
, a flow temperature of 150° C., and 70 parts by weight of plasticizer per 100 parts by weight of polyvinyl chloride. ) A leather-like material was produced in the same manner as in Example 1, except that the following was used.

In addition, as a polyurethane resin, the trade name PANDEX T-5875 manufactured by Dainippon Ink and Chemicals Co., Ltd. was used. The resulting leather-like material was too flexible and lacked the toughness inherent in natural leather.

The one formed to a thickness of 0.4111111 could be torn off with bare hands.

Comparative Example 21 In Example 1, a leather-like material was produced using only a polyurethane resin without using a polyvinyl chloride resin as the thermoplastic resin. The resulting material lacked elasticity and was too hard.

Claims (1)

[Scope of Claims] (1) A leather-like material made by mixing and integrating a thermoplastic resin such as crushed natural leather, wherein the thermoplastic resin is a polyvinyl chloride resin having an average degree of polymerization of 2000 or more, and A leather-like material characterized by using a polyurethane resin having a flow temperature within ±30°C of a flow temperature of a polyvinyl chloride resin. (2) The leather-like material according to claim 1, wherein the pulverized natural leather is 20 to 60% by weight and the thermoplastic resin is 40 to 80% by weight. (3) The pulverized natural leather The leather-like material according to claim 1, wherein the amount of the natural leather is 35 to 45% by weight, and the thermoplastic resin is 55 to 65% by weight. (4) The crushed natural leather is 0.1 to 2III
The leather-like material according to any one of claims (1) to (3), which is a fiber of the invention. (5) The polyvinyl chloride resin and the polyurethane resin both have a flow temperature of 130 to 160. The leather-like material according to any one of claims (1) to (3), wherein the thermoplastic resin is 20 to 30% by weight (4)% of polyvinyl chloride resin; The leather-like material according to any one of claims (+) to (3) and (5), comprising 70 to 80% by weight of a polyurethane resin. (7) Colorant, stabilizer The leather-like material according to any one of claims (1) to (6), characterized by an additive such as the following. Claim (7), wherein the colorant is TiO2.
) The leather-like material described in item 2. (9) Claim No. 7, wherein the stabilizer is ZnO.
) The leather-like material described in item 2. 00) A method for producing a leather-like material by mixing and integrating a pulverized natural leather product and a thermoplastic resin, the method comprising: a pulverized natural leather material dried to a moisture content of 6% by weight or less; and an average degree of polymerization of 2
000 or more, a polyvinyl chloride resin having a flow temperature of 130 to 160°C and a polyurethane resin having a flow temperature of 130 to 160°C are stirred and mixed at a temperature of 160 to 200°C. (10) The method for producing a leather-like material according to claim (10), wherein the crushed natural leather is 20 to 60% by weight and the thermoplastic resin is 40 to 80% by weight. The method for producing a leather-like material according to claim Cl0), wherein the crushed leather material is 35 to 45% by weight, and the thermoplastic resin is 55 to 65% by weight. (14) The method for producing a leather-like material according to any one of claims 00 to 12, wherein the crushed natural leather is a fiber of 0.1 to 2 mm. (14) The thermoplastic resin Claims 00 to (12) consisting of 20 to 30% by weight of polyvinyl chloride resin and 70 to 80% by weight of polyurethane resin
Leather according to any of paragraphs 1. A method for producing shaped materials. (4) The method for producing a leather-like material according to any one of Claims QO to (B), characterized by additives such as colorants and stabilizers. Qφ Claim 0, wherein the colorant is TiO2
A method for producing a leather-like material according to item 2. Or) Claim O, wherein the stabilizer is ZnO
A method for producing a leather-like material according to item (A).