KR980009383A - Main liquid polyurethane composition for shoe outsole - Google Patents

Abstract

A shoe outsole having excellent tensile strength, tear strength and abrasion resistance can be produced by using a polyurethane composition for shoe outsole comprising 0.5 to 1 equivalent of polyol and 1 equivalent of isocyanate.

Description

Main liquid polyurethane composition for shoe outsole

Since this is a trivial issue, I did not include the contents of the text.

FIG. 1 is a graph showing the change in tensile strength according to the hardness of a cured product produced according to the method of the present invention,

FIG. 2 is a graph showing the change in tear strength according to the hardness of a cured product produced according to the method of the present invention,

FIG. 3 is a graph showing changes in wear resistance rate according to hardness of a cured product produced according to the method of the present invention,

[Industrial Applications]

The present invention relates to a main liquid type polyurethane composition for a shoe outsole, and more particularly to a main liquid type polyurethane composition for a shoe outsole having excellent tear strength, tensile strength and abrasion resistance and reduced hardness.

Conventional technology

In general, the footwear components of the shoe are made of insole, midsole and outsole. The outsole is in direct contact with the ground, and is most sensitive to the external conditions such as the condition and characteristics of the ground, and its influence is transmitted first. Therefore, the outsole is required to have excellent tensile, tear properties and abrasion resistance.

The above-mentioned outsole requiring physical properties is conventionally manufactured by a conventional method of baking a rubber or the like. As a method of producing a vulcanized rubber outsole, generally, a natural rubber or a synthetic rubber alone or a mixture thereof is sovlinized in open water or the like and a crosslinking agent, , A filler, a colorant, and an antioxidant, and then subjected to a preliminary molding step through a predetermined kneading step, followed by crosslinking or vulcanization. Furthermore, the outsole made of vulcanized rubber has a disadvantage that the mechanical properties such as tensile strength, tear strength and abrasion resistance are somewhat lower than those of other elastomers. These characteristics are particularly demanded in the case of sports outsole for which high mechanical properties are required.

[Technical Problem]

The inventors of the present invention have been studying a method for manufacturing a shoe outsole having excellent tensile strength, tear strength and abrasion resistance, and it has been found that the object of the present invention can be achieved by using polyurethane having the following advantages. The polyurethane has an excellent abrasion resistance and solvent resistance as compared with vulcanized rubber or other plastic elastomers, and has a tensile strength of 1.5 to 2 times that of natural rubber, particularly excellent in tear strength, and an elastic body manufactured using polyurethane Since it has no double bonds, it has excellent durability, is stable up to 150 ° C, has good electrical insulation, flame retardant property and excellent abrasion resistance. Compared to the various injection molding methods, high-pressure and low-pressure molding methods and other molding methods, the above-mentioned polyurethane is molded in a casting method which is economical and excellent in applicability, and is excellent in tensile, tearing property and abrasion resistance. Outsole can be manufactured. However, since the main component polyurethane elastomer which is widely used at present has a hardness of 90 to 95 A or more, which is too high in the hardness of the cured product, there is a limitation in showing the characteristics of the product. Therefore, it is necessary to maintain hardness of the cured product while maintaining the mechanical properties of the product. However, since the mechanical properties of the cured product depend primarily on the hardness of the cured product, there are many difficulties in lowering the hardness of the cured product.

As a method of lowering the hardness of the main liquid polyurethane described above, there is a method of increasing the soft segment content in the prepolymer and a method of imparting ductility to the cured product by using a polyol curing agent at the time of curing. Among the above methods, when the polyol curing agent is used, the tensile, tearing and abrasion resistance characteristics of the cured product are greatly reduced due to the hardness of the cured product, so that the cured product can not be used for the outsole of a shoe, and the curing time is generally 1 to 3 hours or more In contrast, when the soft segment content in the prepolymer is increased by using a polyol having a high molecular weight, the physical properties of the polyol are not only reduced, but also the elasticity of the cured product can be improved and the hardness can be reduced It has advantages and is being used. In the present invention, a main liquid type polyurethane composition for shoe outsole was prepared by using polytetramethylene glycol, which is a polyether polyol which is chemically more flexible in molecular chain motion than polyester polyol in the synthesis of prepolymer.

It is an object of the present invention to provide a main liquid type polyurethane composition for a shoe outsole having a reduced hardness while maintaining the mechanical properties of the product.

Means for solving the problem

In order to accomplish the above object, the present invention provides a polyol composition comprising 0.5 to 1 equivalent of a polyol; 0.5 to 1 equivalent of polyol and a polyol composition for shoe outsole comprising 1 equivalent of isocyanate; 1 equivalent of isocyanate; And a curing agent in an amount of 0.8 to 1.2 equivalents.

In the present invention described above, the use of a polyether-based polyol, which is polytetramethylene glycol having an average molecular weight in the range of 400 to 4,000, is used as the polyol, since the molecular chain of the polyether-based polyol is flexible and the hardness is lowered Do.

Also in the present invention, the isocyanate is selected from the group consisting of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and mixtures thereof .

In the composition of the present invention, the toluene diisocyanate is preferably a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate in a ratio of 100/0 to 0/100 parts by weight.

In the present invention, the curing agent is selected from the group consisting of 4,4'-methylene (o-chloroaniline), 4,4'-methylene (o-chloroaniline) and trimethylolpropane, The mixing ratio of 4'-methylene (o-chloroaniline) to trimethyl-propane is preferably 100/0 to 10/90 parts by weight.

Hereinafter, the present invention will be described in detail.

The present invention relates to a process for preparing a polytetramethylene glycol / toluene diisocyanate prepolymer having a composition of 0.5 to 1 equivalent of polytetramethylene glycol having an average molecular weight of 400-4,000 with respect to 1 equivalent of isocyanate, (o-chloroaniline) alone or in the presence of a composition of 100/0 to 10/90 composition of 4,4'-methylene (o-chloroaniline) / trimethylolpropane as a curing agent, characterized by producing a main-component polyurethane cured product . At this time, the molecular weight of the polyol is controlled in consideration of the hardness range of the final cured product required for synthesis, or two kinds of polytetramethylene glycols having different molecular weights are mixed with each other in a composition of an equivalent ratio of 1/99 to 99/1.

As the isocyanate used in the present invention, toluene diisocyanate (mixture of 2,4 and 2,6 isomers in a mixing ratio of 100/0 to 0/100 parts by weight), 4,4'-diphenylmediisocyanate, polymethylene polyphenyl A polyisocyanate, a hexamethylene diisocyanate, an isophorone diisocyanate, and a mixture thereof.

In the present invention, when the above prepolymer is cured, the cured main liquid polyurethane cured product is prepared by setting the composition of 4,4'-methylene (o-chloroaniline) / trimethylol propane as an equivalent ratio of 100/0 to 10/90 parts by weight can do. The prepolymers listed above, the cured gels, The mixture is poured into a preheated mold at an appropriate composition ratio and then cured at a constant temperature and pressure in a press equipped with a heating device. At this time, the light-shrinking time becomes longer as the composition of trimethylolpropane increases in the composition of the cured product, and when the equivalent ratio is 100/0 parts by weight, the curing time is 5 minutes at 100 ° C. As the size of the cured product increases, Should be shortened.

[Example]

Hereinafter, preferred embodiments and comparative examples of the present invention will be described. However, the following embodiments are merely preferred embodiments of the present invention, and the present invention is not limited to the following embodiments.

[Example 1]

Synthesis of prepolymer

To remove moisture and the like in the polytetramethylene glycol having an average molecular weight of 450, the polytetramethylene glycol, which is a polyol, was heated to 80 DEG C and then defoamed under a reduced pressure of 1 mmHg for 30 minutes. The polyol was slowly added dropwise to preheated toluene diisocyanate over a period of about 1 hour in a reactor fixed at 50 ° C., and reacted for 2 hours to synthesize a prepolymer.

Curing of prepolymer

The prepolymer synthesized by the above-mentioned method was re-melted at 80 캜, defoamed under a reduced pressure of 1 mmHg for 30 minutes, and then a positive curing agent 4,4'-methylene (o-chloroaniline) calculated according to the following general formula (I) ≪ / RTI > At this time, the curing agent is one which is melted by heating to a melting point or higher.

The amount of the curing agent to be mixed is calculated according to the following general formula (I).

Where x = curing agent (g), S = amount of prepolymer (g), N = measured isocyanate content (%) of prepolymer, E _c = equivalence of curing agent, r _c = equivalent ratio of isocyanate / curing agent

The re-melted prepolymer and the curing agent were mixed in a container, and the mixture was poured into a mold for shoe outsole heated to 100 ° C. within 3 minutes before being mixed with the curing agent. Then, the mixture was poured into the mold piece at a temperature of 100 ° C. at a pressure of 80 kgf / Followed by pressure curing for 5 minutes.

The cured polyurethane outsole was cured in an oven maintained at 70 캜 for 3 hours to prepare a polyurethane cured product for shoe outsole.

[Examples 2 to 4]

A polyurethane cured product was prepared in the same manner as in Example 1 except that the average molecular weight of the polytetramethylene glycol used was adjusted to 850 to 3,000.

[Example 5]

A prepolymer was synthesized by using a polytetramethylene glycol having an average molecular weight of 1,500 in the same manner as in Example 1, and a mixture of 4,4'-methylene (o-chloroaniline) / tricetylolpropane as a curing agent A polyurethane cured product was prepared in the same manner as in Example 1.

[Table 1]

The compositions of Examples 1 to 5

For the comparison according to the kind of the polyol, polypropylene glycol, which is another polyether-based polyol, and polybutylene / ethylene adipate, polyethylene adipate and polycaprolactone diol, which are polyester-based polyols, A polyurethane cured product was prepared in the same manner as in Example 1, except for the synthesis.

[Table 2]

The compositions of Comparative Examples 1 to 5

Investigation of mechanical properties

The hardness, tensile strength, tear strength and NBS wear rate of the cured products prepared according to the above Examples and Comparative Examples were measured in the following manner, and the results are shown in Table 3 below.

A universal tensile tester was used to measure the tensile strength and elongation of the cured product. In accordance with the American Standard Test Specification D-412, the tensile speed was 500 mm per minute, which is the tensile speed of the rubber elastic body, and the first specimen of the planar type having a thickness of 2 ± 0.5 mm was used. The stress-strain curves of the tensile specimens were obtained from the attached X-Y plotters, and the elongation ratios were obtained from the elongation meters with a gauge distance of 20 mm.

A universal tensile tester was used to measure the tear strength of the cured product. A tensile speed of 500 mm / min was used as the tensile speed of the elastic elastomer in accordance with the American Standard Test Specification D-624, and a specimen having a thickness of 2 ± 0.5 mm was used.

To measure the hardness of the cured product, DUROMETASUKA A and D type hardness meters were used. The hardness after a certain period of time (30 seconds) is shown by applying load 10N and measuring 40N perpendicularly to the hardness meter for the A type measurement and D type measurement D-2240 of the American Standard Test Specification D-2240.

To measure the wear rate of the cured product, an NBS abrasion tester with three sample attachment devices was used. According to the Korean Standard Test Specification M-6625 (Measurement of abrasion resistance using NBS standard rubber of vulcanized rubber), the standard abrasion number of NBS standard rubber was determined for each sample attaching device, and then this test was conducted. The abrasion rate The buried sample was continuously removed to minimize errors in the test.

[Table 3]

Mechanical Properties of Cured Products of Examples and Comparative Examples

[Effects of the Invention]

As described above, the main liquid polyurethane elastomer produced according to the present invention is a polyurethane elastomer obtained by mixing a conventional polypropylene glycol / toluene diisocyanate, a polyester polyol (polybutylene / ethylene adipate, polyethylene adipate, polycaprolactone diol) / toluene It has excellent physical properties including tensile and tear properties, abrasion resistance, and slip resistance when the hardness is the same as that of the diisocyanate polyurethane adduct, and since the hardness can be controlled freely, it has a Shore 75 ~ 95A range, It can also be used as antifouling mat oil-resistant sheet and various industrial main and subsidiary materials.

Claims (12)

0.5 to 1 equivalent of polyol, and 1 equivalent of isocyanate. The polyurethane composition according to claim 1, wherein the polyol is a polyether polyol. 3. The polyurethane composition according to claim 2, wherein the polyether polyol is polytetramethylene glycol having an average molecular weight in the range of 400 to 4,000. The method of claim 1 wherein said isocyanate is selected from the group consisting of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and mixtures thereof Wherein the polyurethane composition is selected from the group consisting of: The polyurethane composition for a shoe outsole according to claim 4, wherein the toluene diisocyanate is a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate in a ratio of 100/0 to 0/100 parts by weight. 0.5 to 1 equivalent of a polyol, 1 equivalent of an isocyanate, and 0.8 to 1.2 equivalent of a curing agent. The polyurethane composition according to claim 6, wherein the polyol is a polyether polyol. The polyurethane composition according to claim 7, wherein said polyether polyol is polytetramethylene glycol having an average molecular weight in the range of 400 to 4,000. 7. The composition of claim 6, wherein the isocyanate is selected from the group consisting of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, Wherein the polyurethane composition is selected from the group consisting of: The polyurethane composition for shoe outsole according to claim 9, wherein the toluene diisocyanate is a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate in a ratio of 100/0 to 0/100 parts by weight. 7. The shoe according to claim 6, wherein the curing agent is selected from the group consisting of 4,4'-methylene (o-chloroaniline), 4,4'-methylene (o-chloroaniline) Polyurethane cured products. The polyurethane cured product for shoe outsole according to claim 11, wherein the mixing ratio of 4,4'-methylene (o-chloroaniline) to trimethylol propane is 100/0 to 10/90 parts by weight. ※ Note: It is disclosed by the contents of the first application.