JP3851921B1 - Foot sole shape forming method for footwear and foot sole shape forming method for cup insole - Google Patents

Abstract

An object of the present invention is to obtain a resin foam capable of easily holding a shape deformed by an external force. A material that can be molded without time and effort.
A resin composition containing a low density polyethylene (A), an ethylene vinyl acetate copolymer (B), a filler (C), a foaming agent (D), and a cross-linking material (E). A foamed resin foam a having a mass ratio of low density polyethylene (A) to ethylene vinyl acetate copolymer (B) of (A) / (B) = 95/5 to 90/10 Let it be foam a.
[Selection] Figure 1

Description

The present invention relates to a sole surface shape forming method for sole surface shape forming method and Kappuinsoru footwear capable of retaining a shape deformed by body weight easily.

For example, footwear is required to absorb the impact when touched down to reduce the burden on the foot and not to get tired even when used for a long time. Accordingly, an insole that matches the shape of the back of each person's foot so that the balance of the body is not lost is desired. For example, footwear using a sponge that deforms when an external force is applied as an insole (see Patent Document 1), insole material There is a footwear (see Patent Document 2) that uses a thermoplastic resin for forming the back of the foot by inserting the foot by heating the thermoplastic resin before use.
Utility model registration No. 3097517 JP 2005-74085 A

However, in the former, a specific insole material that can easily hold a shape deformed by an external force has not been disclosed. In the latter case, since the thermoplastic resin of the insole is heated and molded so as to conform to the shape of the back of the foot before the start of use, there is a problem that it takes time and effort.

The present invention has been made to eliminate the above-described problems, and provides a foot sole shape forming method for footwear and a foot sole shape forming method for a cup insole that can easily retain a shape deformed by weight . The purpose is to do.

Claim 1 is footwear in which an insole is provided on an outsole, wherein the insole is formed so as to surround an inner core member made of a resin foam and an outer periphery of the inner core member, and the inner core An outer core member formed of a member harder than the member, and a covering member covering the outer surface of the outer core member and the inner core member. The resin foam includes low-density polyethylene (A), ethylene acetate Low-density polyethylene (A) obtained by foaming a resin composition containing a vinyl copolymer (B), a filler (C), a foaming agent (D), and a cross-linking material (E) And the ethylene vinyl acetate copolymer (B) are in a mass ratio of (A) / (B) = 95/5 to 90/10 , with the foot in contact with the covering member, The bubbles in the resin foam are crushed and plastically deformed to change along the shape of the back of the foot. It is intended to be.

Claim 2 is the ratio of the total mass of the low density polyethylene (A) and the ethylene vinyl acetate copolymer (B) to the mass of the filler (C) ((A) + (B)). / (C) = 70/30 to 80/20.

Claim 3, the central core member composed of a tree fat foam, is formed so as to surround the outer periphery of the central core member, an outer core member formed of rigid member from said wick member, the outer core And a covering member provided so as to cover the entire core member, and the resin foam includes a low density polyethylene (A), an ethylene vinyl acetate copolymer (B), a filler ( and C), foaming agent (D), a resin composition containing a crosslinking material (E) be one foamed, with low density polyethylene (a) and ethylene-vinyl acetate copolymer (B) The mass ratio is (A) / (B) = 95/5 to 90/10 , the foot is brought into contact with the covering member, and the plastic body deforms by crushing the bubbles in the resin foam by the weight applied to the back surface of the foot. It is made to deform | transform along the shape of a foot sole .

Claim 4 is the ratio of the total mass of the low density polyethylene (A) and the ethylene vinyl acetate copolymer (B) to the mass of the filler (C) according to claim 3 ((A) + (B)). / (C) = 70/30 to 80/20.

According to the first aspect of the present invention, since the core member of the insole of the footwear is composed of the resin foam according to the first aspect, the shape of the sole of the foot, which is different for each person due to the short-time use of the footwear. Can be formed on the surface of the insole, and footwear suitable for the shape of the back surface of each person can be obtained without taking time and effort.

According to the third aspect of the present invention, the cup insole has the core member made of the resin foam according to the second aspect , so that the footwear fitted with the cup insole can be used for a short time. Different shapes of the soles can be formed on the surface of the cup insole for each person, and footwear suitable for each person's soles can be obtained without taking time and effort.

An embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a schematic cross-sectional view of a resin foam used in the present invention, where a is a resin foam, 1 is a resin substrate, 2 is a filler (filler (C)), and 3 is a bubble. Show.

The resin substrate 1 constitutes the skeleton of the resin foam a, and is formed by crosslinking a low density polyethylene (A) or an ethylene vinyl acetate copolymer (B) with a crosslinking agent (E). The mass ratio of A) to the ethylene vinyl acetate copolymer (B) is (A) / (B) = 95/5 to 90/10. This is because, in the characteristics of the compression residual strain rate described later, when the mass ratio of the low density polyethylene (A) is less than 90/10, the value of the compression residual strain rate becomes small, and the retainability of the shape deformed by an external force is deteriorated. This is because when the mass ratio exceeds 95/5, the decrease in tensile strength becomes large and breakage tends to occur.

The filler 2 (filler (C)) is added to adjust the hardness of the resin foam a, and the material is selected and the addition amount is adjusted according to the application. Therefore, for example, when used as an insole of footwear, in order to obtain an appropriate feel on the sole of the foot when the footwear is worn, a fine powder of calcium carbonate that can make the bubbles 3 of the resin foam a fine is used, preferably The ratio of the total mass of the low density polyethylene (A) and the ethylene vinyl acetate copolymer (B) to the mass of the filler (C) is ((A) + (B)) / (C) = 70 / 30-80 / 20 to be added.

The bubbles 3 are formed in a closed cell state by foaming of the foaming agent (D) in the manufacturing process of the resin foam a.

Next, the manufacturing method of the resin foam a of this invention is demonstrated.

First, a low-density polyethylene (A), an ethylene vinyl acetate copolymer (B), a filler (C), a foaming agent (D), and a crosslinking agent (E) are mixed at a predetermined ratio and sufficiently kneaded to obtain a resin composition. Formulate.

Then, for example, by using a forming method such as injection molding or extrusion molding, the prepared resin composition is foamed while maintaining the temperature at 140 ° C. to 180 ° C., and molded into a predetermined shape to obtain a resin foam a. .

Here, the crosslinking agent (E) crosslinks the molecules of the low density polyethylene (A) and the ethylene vinyl acetate copolymer (B) by crosslinking reaction at the time of heating and foaming, and dicumyl peroxide ( Materials such as DCP) are used. The foaming agent (D) forms bubbles 3 in the resin foam a during heat foaming, and a material such as azodicarbonamide (AC) is used.

The resin composition may contain antimony carbonate (Sb ₂ (CO ₃ ) ₃ ). This antimony carbonate has the function of increasing the flexibility of the molded resin foam a, and can be easily bent, particularly when processed into a sheet. Further, a color former such as titanium oxide (TiO ₂ ) or other additives may be added depending on the application.

Examples of the present invention will be described below together with comparative examples.
(1) Main materials used in (Example) and (Comparative Example) Low-density polyethylene (A): Low-density polyethylene (LDPE) manufactured by Shanghai Petrochemical Co., Ltd.
-Ethylene vinyl acetate copolymer (B): manufactured by Beijing Denghua High-Technology Co., Ltd. Ethylene vinyl acetate copolymer (EVA)
-Filler (C): Calcium carbonate (CaCO ₃ ) manufactured by Zhejiang Ryoka Co., Ltd.
-Foaming agent (D): Azodicarbonamide (AC) manufactured by Zhejiang Haihong Holding Co., Ltd.
Crosslinking agent (E): Dicumyl peroxide (DCP) manufactured by Shanghai Petrochemical Co., Ltd.
(2) Composition of Resin Composition of (Example) and (Comparative Example) Table 1 shows the composition of main materials of the resin compositions of Examples and Comparative Examples (each value in the table represents parts by mass). The values of the filler (C), the foaming agent (D), and the crosslinking agent (E) are parts by mass when the total mass of the low density polyethylene (A) and the ethylene vinyl acetate copolymer (B) is 100 parts by mass. Represents.) Although not shown in Table 1, in Examples 1 to 3 and Comparative Examples 1 and 2, antimony carbonate (Sb ₂ (CO ₃ ) ₃ ) was replaced with low-density polyethylene (A) and an ethylene vinyl acetate copolymer (B ) Is added in an amount of 1.8 parts by mass per 100 parts by mass.

Table 2 shows the measurement results of the properties measured for the examples and comparative examples by selecting the compressive residual strain rate and the tensile strength as indices of the properties of the resin foam a. Each characteristic is a value measured by the following evaluation method.
Compressive residual strain rate: test piece 50 mm × 50 mm × 15 mm (d0 = 15 mm)
Test temperature 15 ± 1 ° C
Compression rate 53% (thickness 15 mm before compression, thickness 7 mm when compressed)
Compression time 3 hours
Compression residual strain rate (%) = (d0−dr) / d0 × 100
d0: thickness before compression (mm), dr: thickness after release of compression load (mm)
・ Tensile strength: Conforms to JIS K6251 "Vulcanized rubber and thermoplastic rubber-Determination of tensile properties"

As shown in Table 2, the characteristics of the compression residual strain rate are higher in Examples 1 to 3 and Comparative Example 2 than in Comparative Example 1 (thickness does not tend to return to the original value even when the compression load is released). On the other hand, in Comparative Example 1, the value was as low as 20% (the tendency for the thickness to return to the original value after the compression load was released).

On the other hand, in the resin foam using the resin composition of Comparative Example 2 that does not contain an ethylene vinyl acetate copolymer, the compressive residual strain ratio is high as in Examples 1 to 3, but the tensile strength is 0. The value was 19 MPa, which was lower than those of Examples 1 to 3, and was practically unusable for an insole or the like (for example, when used for an insole, the tensile strength needs to be 0.20 MPa or more).

By the way, it was possible to increase the compression residual strain ratio of the resin foam a formed by increasing the mass ratio of the low density polyethylene (A) to the ethylene vinyl acetate copolymer (B). This is because by increasing the mass ratio of A), the foaming ratio (volume expansion rate) is increased so that many bubbles 3 can be formed in the resin substrate 1. It is thought that it is because it is crushed and plastically deformed, and this deformed shape can be maintained. The upper limit of the mass ratio of the low density polyethylene (A) and the ethylene vinyl acetate copolymer (B) is (A) / (B) = 95/5 because of the tensile strength of the formed resin foam a. The lower limit is set to (A) / (B) = 90/10 because the decrease in the compressive residual strain rate is reduced and external force is applied. This is because the retainability of the deformed shape is deteriorated.

Next, examples of footwear and cup insole using the above-described resin foam a will be described.

2 to 4, b is footwear, and footwear b has an insole 20 provided on an outsole 14, and the insole 20 includes a core member 11 made of a resin foam a, and the center member 11. An outer core member 12 formed so as to surround the outer periphery (for example, formed in a frame shape so as to surround the outer periphery of the core member 11), a member harder than the core member 11, and the outer core member 12 And a covering member 13 that covers the outer surface of the core member 11. Reference numeral 15 denotes an upper member, which is provided when the footwear b is a sandal.

The core member 11 is used by molding the resin foam a into a predetermined shape, and maintains the shape deformed by an external force to match the surface of the insole with the shape of the back of the foot.

The outer core member 12 retains the outer shape of the insole 20 by preventing excessive deformation caused by an external force applied to the core member 11, and is harder than the core member 11 made of the resin foam a. An ethylene vinyl acetate copolymer foam or the like is used.

The covering member 13 is made of a decorative material or the like for improving the appearance of the footwear b, and is preferably a material having elasticity so that it can follow the deformation of the contacting core member 11.

The outsole 14 has a buffering action so that the foot b does not directly receive an impact due to unevenness of the ground surface when the footwear b contacts the ground or the like, and is made of polyurethane, ethylene vinyl acetate copolymer, synthetic rubber. Such materials are used.

The upper member 15 abuts against the instep of the foot when the footwear b is put on, and fixes the foot to the footwear b, and materials such as polyurethane, polyvinyl chloride, and leather are used.

Next, the usage method of the footwear provided with the insole based on this invention is demonstrated.

Before using the footwear b, as shown in FIGS. 3, 6 (a), and 7 (a), the insole 20 has not yet been applied with an external force, so the contact surface of the foot has a substantially planar shape. It has become.

When the footwear starts to be used, as shown in FIG. 5A, the back surface of the foot 30 first comes into contact with the covering member 13 of the insole 20, and the insole 20 is deformed by an external force (weight) applied to the back surface of the foot. At this time, since the shape of the sole surface in contact with the upper surface of the insole 20 has irregularities, the amount of settlement differs in each part, and deforms along the shape of the sole surface. The amount of deformation is not only different in each part of the sole, such as the toe part, the arch part, and the buttocks part, but also greatly varies depending on individual differences (differences in the shape of the soles).

Here, since the core member 11 in the insole 20 is made of the resin foam a and has a high moldability, it is shown in FIGS. 5 (b), 6 (b), and 7 (b). As shown, the upper surface of the insole 20 retains the shape of the back of the foot even after the footwear is removed and the external force is removed. Therefore, by using the footwear for a short time (for example, about 3 hours), the shape of the sole can be formed on the surface of the insole, and it can be adapted to the shape of the sole of the foot without taking time and effort. You can get footwear.

By the way, in the above-mentioned embodiment, an example of the footwear in which the insole 20 and the outsole 14 are integrally provided in advance is shown. However, as shown in FIG. It may be produced as a detachable insole).

The cup insole 21 includes a core member 11 made of a resin foam a, and an outer core member 12 that is formed to surround the outer periphery of the core member 11 and is made of a member harder than the core member 11. The outer core member 12 and the covering member 16 provided so as to cover the entire core member 11 are included (see FIG. 8B). Therefore, since the cup insole 21 can be used by being worn on the insole of various ready-made footwear, a different shape of the sole of the foot can be obtained for each person by using the footwear with the cup insole 21 for a short time. It can be molded on the surface of the insole, and footwear suitable for the shape of the back of each person can be obtained without taking time and effort. The covering member 16 is made of the same material as the covering member 13.

It is a schematic sectional drawing of the resin foam a used for the foot sole shape formation method of the footwear of this invention. It is a perspective view of the footwear which uses the resin foam a of FIG. It is the longitudinal cross-sectional view cut | disconnected along CC line of FIG. It is the cross-sectional view cut | disconnected along the DD line | wire of FIG. It is the longitudinal cross-sectional view which shows the use condition of the footwear of FIG. 2, Comprising: (a) is the state which put on the footwear, (b) is the figure showing the state which took off the footwear. It is the longitudinal cross-sectional view cut | disconnected along the AA line of FIG. 2, Comprising: (a) is a figure before use and (b) represents the state at the time of use. It is the longitudinal cross-sectional view cut | disconnected along the BB line | wire of FIG. 2, Comprising: (a) is a figure before use and (b) represents the state at the time of use. It is a figure showing the other example of FIG. 2, (a) is a perspective view of an insole, (b) is the longitudinal cross-sectional view cut | disconnected along the EE line of (a).

Explanation of symbols

a Resin foam b Footwear 1 Resin base 2 Filler 3 Air bubbles 11 Core member 12 Outer core member 13 Cover member 14 Outsole 16 Cover member 20 Insole 21 Cup insole

Claims (4)

Footwear having an insole provided on an outsole, wherein the insole is formed of a resin core and is formed so as to surround an outer periphery of the core member, and is a member harder than the core member. The outer core member is formed, and the outer core member and a covering member that covers the outer surface of the inner core member. The resin foam includes low-density polyethylene (A) and an ethylene vinyl acetate copolymer ( and B), filler (C), and blowing agent (D), crosslinker (E) and be those obtained by foaming the resin composition containing, low-density polyethylene (a) and the ethylene-vinyl acetate copolymer The mass ratio to the polymer (B) is (A) / (B) = 95/5 to 90/10 , the foot is brought into contact with the covering member, and the weight applied to the back surface of the foot causes the resin foam It is plastically deformed to crush the air bubbles to deform along the sole surface shapes Sole surface shape forming method for footwear, characterized. The ratio of the total mass of the low density polyethylene (A) and the ethylene vinyl acetate copolymer (B) to the mass of the filler (C) is ((A) + (B)) / (C) = 70 / 30-80 The foot sole shape forming method for footwear according to claim 1, wherein A central core member composed of trees fat foam, the central core is formed so as to surround the outer periphery of the member, and an outer core member formed of rigid member from said wick member, said wick and the outer core member A covering member provided so as to cover the entire member, and the resin foam includes a low density polyethylene (A), an ethylene vinyl acetate copolymer (B), a filler (C), and a foam. agent (D) and the resin composition containing a crosslinked material (E) be one foamed mass ratio of low-density polyethylene (a) and ethylene-vinyl acetate copolymer (B) (a ) / (B) = 95/5 to 90/10 , the foot is brought into contact with the covering member, and the weight applied to the back surface of the foot is crushed and plastically deformed by bubbles in the resin foam. A method for forming a back surface shape of a cup insole , wherein the shape is deformed along the shape . The ratio of the total mass of the low density polyethylene (A) and the ethylene vinyl acetate copolymer (B) to the mass of the filler (C) is ((A) + (B)) / (C) = 70 / 30-80 4. The method for forming the back surface shape of a cup insole according to claim 3, wherein:

Images