JPH04261602A - Manufacturing method of shoe sole material - Google Patents

Abstract

PURPOSE:To make it possible to walk with stability even when walking on a floor or footing which is wet with water or oil. CONSTITUTION:Short fibers having a fiber length of 0.1 to 10mm and an aspect ratio L/D of fiber length L to fiber diameter D of 5000 or less is blended by 0.1-30vol.% of an elastic base material 2. On a rubber sheet in which short fibers 2 are oriented in the direction of the thickness of the sheet, a second rubber sheet whose unvulcanized viscosity is 90% or less of that of the first sheet material is laminated. After the vulcanizing press of the above sheets, the material is buffed and short fibers are exposed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shoe sole material, and more particularly to a method for producing a shoe sole material that is stable against environmental changes.

0002

[Prior Art] The soles of sports shoes and safety shoes have conventionally been made of rubber or urethane. If there is oil on the floor, the coefficient of friction will be much lower than it would normally be. Therefore, when short fibers are mixed into the rubber used as the sole material and oriented in the thickness direction of the sole material, the protruding short fibers will prevent water or oil from forming on surfaces that are wet with water or oil. It is known that the coefficient of friction can be obtained with almost no change from the normal state (for example, in the
(See Publication No. 200909).

0003

[Problem to be Solved by the Invention] Therefore, the above can be produced by cutting and laminating sheets in which short fibers are oriented in the longitudinal direction and inserting the sheets into the recesses of a mold, but this takes a very long time. Poor productivity. Additionally, if a flat sheet oriented in the thickness direction is placed on a mold and pressed, the orientation of the short fibers in the protrusions of the sole material will be disturbed, making it impossible to obtain the desired quality. .

[0004] Therefore, as a result of repeated commercial research, the inventor found that
It has been found that when a sheet with short fibers oriented in the thickness direction is press-cured as is, the flow of rubber is such that the excess rubber in the concave parts of the sole material flows into the convex parts. Considering that it is generally known that the direction is always the direction of rubber flow, in the convex part, the lateral orientation following the flow from the concave part appears on the surface layer, and the thickness direction orientation is hidden inside. I also found out that it can happen.

[0005] An object of the present invention is to provide a method for producing a shoe sole material that allows the user to walk normally with a sense of stability even when the floor or scaffolding is wet with water or oil.

[0006]

Means for Solving the Problems The invention according to claim 1 provides that the short fibers have a fiber length of 0.1 to 10 mm and an aspect ratio L/D of fiber length L to fiber diameter D of 5000 or less. .1～
30% by volume of the first rubber sheet material, the short fibers of which are oriented in the thickness direction, the viscosity of the unvulcanized rubber sheet material is 90% or less of that of the first sheet material. The second rubber sheet material is laminated, and then both of the above sheet materials are sandwiched between molds and vulcanized, and the sole material is molded so that the first rubber sheet material becomes the bottom surface. .

[0007] According to the second aspect of the invention, the first rubber sheet material has a degree of orientation of short fibers of 30% in the sheet thickness direction.
As described above, in the invention of claim 3, the bottom surface of the shoe sole material is buffed after vulcanization, and in the invention of claim 4, the exposed amount of short fibers after buffing is 0.01 to 1 mm. It is.

[0008]

According to the invention of claims 1 to 4, the viscosity of the second rubber sheet material is 90% of the viscosity of the first rubber sheet material.
% or less, the viscosity of the second rubber sheet material is smaller than the viscosity of the first rubber sheet material, so during molding,
The rubber of the first rubber sheet material, in which the short fibers are oriented in the thickness direction, does not flow, and only the remaining rubber of the second rubber sheet material in the concave part of the sole is on the convex part side of the sole. The first rubber sheet, in which the short fibers are oriented in the thickness direction, is pressed against the wall of the mold on the surface of the convex part of the shoe sole without disturbing the orientation of the short fibers. , shoe sole materials are manufactured. In particular, according to the inventions of claims 3 and 4,
Since the short fibers are exposed from the surface of the sole, the coefficient of friction does not change significantly depending on the condition of the floor, etc.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a sole material for work shoes, which is mainly used for the soles of work shoes and sports shoes for people who work in environments where floors and scaffolding are wet with water and oil. It will be done.

In the sole material 1, the bottom surface of the elastic base material 2 is polished by buffing, and the short fibers 3 are removed from the bottom surface by 0.0.
They protrude by about 1 to 1 mm, and when walking, etc., the protruding portions of the short fibers 3 cut the water film 5 (or oil film) on the floor surface 4, so that the coefficient of friction does not change significantly.

[0012] The elastic base material 2 is made of natural rubber or SBR,
Made of synthetic rubber such as CR, thermoplastic elastic polymers such as urethane and PVC, natural fibers such as cotton, wool and cellulose, or synthetic fibers such as polyamide, polyester, vinylon and aramid fibers, or copper, Short fibers 3 made of metal fibers such as stainless steel or steel or inorganic fibers such as glass or ceramic are blended.

[0013] The short fibers 3 have a fiber length of 0.1 to 10
mm, but if we consider the processability for dispersing and orienting the elastic base material 2, the aspect ratio (L/
D) is desirably 5000 or less (preferably 300 or less). In addition, short fiber 3 was included in the total composition by 0.1
It is preferable to mix it in an amount of up to 30% by volume (preferably 2 to 5% by volume). Further, it is preferable that the short fibers protrude from the surface by 0.01 mm or more, preferably 0.05 mm or more so that water or oil films can be cut.

[0014] In order to manufacture the above-mentioned shoe sole material, for example, 25% by volume or less of short fibers cut into 1 to 5 mm pieces are mixed into a predetermined composition of the elastic base material 2, kneaded in a well-known manner, and then rolled. -Using tools, calendars, extruders, injection molding machines, etc.
An unvulcanized first rubber sheet material to be used as a shoe sole is prepared in which short fibers are oriented in the thickness direction of the sheet with an orientation ratio of 30% or more. During this molding, the thickness of the sheet is adjusted to match the thinner part of the mold for forming the sole material.

[0015] When this first rubber sheet material is molded into a shoe sole material, the thickness direction (short fiber orientation direction) of the first rubber sheet material is the same as that of the shoe sole material after molding. Apply it to the lower mold for forming the sole material so that it is in the thickness direction.

[0016] Also, the same polymer as the first rubber sheet material (short fibers may or may not be mixed in) is used, and the viscosity is 90% that of the first rubber sheet material. %
Using the following elastic base materials, rolls, calenders,
Using an extruder, injection molding machine, etc., the thickness of the second rubber sheet material is adjusted to be 1 to 1.5 times the amount obtained by subtracting the capacity of the first rubber sheet material from the mold capacity. A rubber sheet material is laminated on top of the first rubber sheet material. In other words, the thickness of the first rubber sheet material in which short fibers are oriented is made thinner, and the thickness of the second rubber sheet material is reduced.
Adjust the overall thickness of the sole material with the rubber sheet.

Furthermore, an upper molding die is placed on top of the two laminated rubber sheet materials, and vulcanization is performed using a press. By doing so, only the remaining rubber of the second rubber sheet material, which has a low viscosity and is located in the concave part of the sole, flows toward the convex part of the sole, and the surface of the convex part of the sole becomes thick. The first rubber sheet with short fibers oriented in the thickness direction is pressed against the wall of the mold, and the first rubber sheet material is vulcanized with the short fibers oriented in the thickness direction. , no disturbance in the orientation of the short fibers occurs. As a result, without disturbing the orientation of the short fibers,
Shoe sole materials are manufactured. In this molding, the second rubber sheet material basically does not appear on the surface of the sole material.

After vulcanization, the surface of the sole is buffed so that the short fibers protrude from the sole surface by 0.05 to 0.5 mm. It is sufficient that the short fibers protrude at least only from the bottom surface of the convex portion of the shoe sole.

According to the above structure, the soles of work shoes are very slippery in environments where the floor or scaffolding is wet with water or oil, and therefore, it is necessary to work in such environments, for example, in construction, construction, etc.
Although this was not desirable in terms of safety in fisheries, iron industry, etc., the short fibers 3 protruding from the soles of shoes cut and destroy water and oil films, which made it difficult to slip, making it possible to use it on floors and scaffolding that were previously extremely slippery. This allows you to work safely and with peace of mind. Then, in the following table,
The results of testing the friction coefficient and slip property of the invention examples and comparative examples 1, 2, and 3 are shown below.

[0020] An example of the present invention is a first rubber sheet material in which short fibers have a fiber length of 3 mm, a fiber diameter of 14 μm, and an aspect ratio of 214, and are blended with 10% para-aramid fibers and oriented in the sheet thickness direction. A second rubber sheet material having a lower viscosity than the first rubber sheet material was laminated on the upper side, press vulcanization was performed, and the sole surface was buffed after vulcanization. This is the same case as the present invention example except that the short fiber orientation direction is the transverse direction, and comparative example 2 is the same as the present invention example except that the second rubber sheet material has a higher viscosity than the first rubber sheet material. This is the same case as the present invention example, Comparative example 3 is a case where the elastic base material constituting the first rubber sheet material of the present invention example is formed alone, and Comparative example 4 is not buffed after vulcanization. Comparative Example 5 is a case where the sole material is the same as the example of the present invention except for the above points, and Comparative Example 5 is a case where a conventional shoe sole material consisting of a single elastic base material with no short fibers mixed therein is used. In addition, in the example of the present invention, the amount of protrusion of the short fibers from the surface of the sole after buffing is about 0.1 mm.

The composition of the base rubber of the first rubber sheet material is as follows.

[0022] NBR-N230SL

70 PHR BR0061

30 Zinc oxide

5 FEF black

50 hard clay

50DOP

15 Triethanolamine
1 Vulcanization accelerator MBT

1.5 Vulcanization accelerator DPG

0.5 sulfur


1.5 Furthermore, the composition of the base rubber of the second rubber sheet material with low viscosity, which is laminated on the upper side of the first rubber sheet material, is as follows.

[0023] NBR-N230SL

70 PHR BR0061

30 Zinc oxide

5 GPF black

20DOP


5 Triethanolamine

1 Vulcanization accelerator MBT

1.5 Vulcanization accelerator DPG

0.5 sulfur

1.5 Furthermore, when an elastic base material with high viscosity was used as the second rubber sheet material, 30% by volume of short fibers were mixed into the base rubber of the first rubber sheet material.

[0024] The coefficient of friction is expressed as an index using Heydon Model 10 as a measuring device, with the case of dry (dry) in Comparative Example 5 set as 100.

[0025] Slip property was evaluated by a slip sensitivity test in which a sole material was actually attached to a shoe sole. In other words, ◎(
3 (no slipping at all), △ (slightly slipping), × (slipping a lot)
Evaluated in stages.

[0026]

[Table 1]

Although the above embodiments have mainly been described with respect to work shoes, it goes without saying that the present invention can also be applied to sole materials of all types of shoes, such as sports shoes.

[0028]

Effect of the invention According to the invention of claims 1 to 4,
A shoe sole material in which short fibers are oriented in the thickness direction can be easily produced. In particular, in the shoe sole material manufactured according to the inventions of claims 3 and 4, the short fibers protrude from the sole surface, so even if the floor is dry or wet with water or oil. Since the coefficient of friction does not change, it is advantageous in terms of safety when used as sports shoes or safety shoes.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the state of a shoe sole material on a floor surface wet with water.

[Explanation of symbols]

1 Shoe sole material 2 Elastic base material 3 Short fiber

Claims (4)

[Claims] 1. 0.1 to 30% by volume of short fibers having a fiber length of 0.1 to 10 mm and an aspect ratio L/D of fiber length L to fiber diameter D of 5000 or less are blended, On the first rubber sheet material whose fiber orientation direction is the thickness direction,
A second rubber sheet material whose viscosity when unvulcanized is 90% or less of the first sheet material is laminated, and both of the above sheet materials are then placed in a mold and vulcanized. 1. A method of manufacturing a shoe sole material, which comprises molding the shoe sole material so that the rubber sheet material of No. 1 serves as the bottom surface. 2. The method for manufacturing a shoe sole material according to claim 1, wherein the first rubber sheet material has a degree of orientation of short fibers of 30% or more in the sheet thickness direction. 3. The method of manufacturing a shoe sole material according to claim 1, wherein the bottom surface of the shoe sole material is buffed after vulcanization. 4. The exposed amount of short fibers after buffing is 0.
4. The method of manufacturing a shoe sole material according to claim 3, wherein the thickness is 0.01 to 1 mm.