JPH0271701A - Fitting material for ski boots - Google Patents

Abstract

PURPOSE:To enable forces to be properly transmitted from skier's feet to ski boots even if this fitting material is used for a long period of time by forming them using a specific copolymer whose main constituents are vinyl acetate, acrylic components or vinyl acetate-acrylic components and ethylene, and whose constituents other than ethylene occupies a specific ratio of the total amount, and further whose number-average molecular weight is specific. CONSTITUTION:Acrylic components comprises acrylic acid, methacrylic acid and their derinatives represented by methyl acrylate, methyl methacrylate or the like and its derivatives, and the copolymer thereof comprises also other monomers, such as butadiene which are added as modifier to ethylene, vinyl acetate, acrylic components so as to be copolymerized. In the copolymer composing fitting material, the ratio of components other than ethylene is to be 20wt% or more. If the ratio is less than 20wt%, the fitting material becomes too hard, so that it pains skier's feet. When such copolymer is melted, fluidity is impaired and further much melting energy is required. In addition, the number average molecular weight Mn of the copolymer is to be 30,000 or less. If it exceeds 30,000, the fluidity at the time of melting the copolymer is impaired.

Description

[Detailed Description of the Invention] "Field of Industrial Application" The present invention is directed to a ski boot that is interposed between the hard shell of a ski boot and the foot, and adapted to the shape of the foot so that the foot can be moved into the shell in a pain-free manner. This relates to the fitting material to be held.

BACKGROUND OF THE INVENTION The shell of a ski boot is made rigid so that the movements of the skier's legs can be immediately transmitted to the ski. However, the shape of the foot accommodated within this shell varies from person to person. Therefore, a fitting material is interposed between the shell and the foot in order to absorb the differences in the shape of the foot and hold the foot in a pain-free manner.

Conventionally, this fitting material has been made of gum pads or soft urethane foam.

Conventional fitting materials made of gum pads become easily deformable when heated with body temperature.

Such fitting materials include those made of low-melting paraffin wax and silica, those made of natural rubber and cork, those made of isobutylene-isoprene copolymer, paper fiber, and talc, or those made of alkyd resin, expanded polystyrene, and stearin. Those consisting of zinc oxide, etc. were provided. These gum pads were used by being housed in pads or inner boots.

Furthermore, the conventional fitting material made of flexible urethane foam is of a two-liquid reaction type, in which two types of reaction liquids are mixed and injected into the gap between the shell and the foot under foaming pressure and hardened.

``Problems to be Solved by the Invention'' The conventional fitting material made of gum pads is easily deformed by being warmed by body temperature. There were complaints that the ski boots would soften and sag downward, or that they would be pushed out of the area if force was applied continuously, making it impossible to adequately transmit force from the foot to the ski boot. Further, particularly in the case of gum pads using paraffin wax, there is a problem in that a large amount of melting energy is required due to the high crystallinity.

On the other hand, fitting materials made of soft urethane foam are
If the flow balance is disrupted when the reaction solution is injected between the shell and the foot, the foot will be held unevenly within the shell, and once it hardens, its shape will be fixed and cannot be corrected. There was a problem in that the risk was high and the fitting process required both the seller and the buyer to have a high level of skill. Moreover, since soft urethane foam is extremely flexible, it must be covered with considerable pressure to ensure sufficient force transmission between the foot and the ski boot, which can cause congestion if the ski boot is continuously worn. I had a complaint that my feet hurt.

The present invention has been developed in view of the above circumstances, so that it is possible to effectively transmit force from the foot to the ski shoe without causing any flow shift during use, and it also allows the foot to be held without pain, and the fitting process is easy. The purpose is to provide fitting materials.

``Means for Solving the Problems j'' In the present invention, vinyl acetate, an acrylic component or a vinyl acetate-acrylic component, and ethylene are the main components, and the proportion of components other than ethylene is 20% by weight or more, and several The above problem was solved by forming a fitting material using a copolymer having an average molecular weight of 30,000 or less.

Here, the acrylic component refers to acrylic acid, methacrylic acid, and derivatives thereof, typified by methyl acrylate, methyl methacrylate, ethyl acrylate, and the like.

This copolymer also includes those modified by copolymerizing other monomers, such as butadiene, in addition to ethylene, vinyl acetate, and acrylic components.

The copolymer constituting the fitting material of the present invention must have a proportion of components other than ethylene of 20% by weight or more. The proportion of components other than ethylene in the copolymer is 20%
If it is less than that, the fitting material will become too hard and will cause pain. Further, during melting, fluidity is impaired and a large amount of melting energy is required.

Further, the number average molecular weight Mn of the copolymer must be 30,000 or less. When Mn exceeds 30,000, there is a disadvantage that fluidity when melting the copolymer is impaired.

Specific examples of this type of copolymer include Acrift (trade name; manufactured by Sumitomo Chemical Co., Ltd.), which is an ethylene-methyl methacrylate copolymer; manufactured by Sumitomo Chemical Co., Ltd.), NUC-EEA (trade name; manufactured by Nippon Unicar Co., Ltd.), which is an edilene-ethyl acrylate copolymer, Evaflex EEA (trade name; manufactured by DuPont Mitsui Co., Ltd.), and Refspol. (Product name: Manufactured by 8 Stone Co., Ltd.)
Pol, an ethylene-methyl acrylate copolymer
Examples include y-E th (trade name; manufactured by Gulf Co., Ltd. or Chomen Co., Ltd.).

Further, a liquid plasticizer is added to the copolymer made of ethylene, etc., if necessary, to adjust the physical properties such as hardness as appropriate.

As liquid plasticizers, dibasic acid esters such as dioctyl phthalate (DOP) can be suitably used.
A variety of materials can be used, including those based on phosphoric acid esters, sebacic acid esters, adipate esters, polyesters, and the like.

The copolymer constituting the fitting material of the present invention usually has the following physical properties.

■Glass transition temperature -15℃ or less.

■Shore hardness (Type A) in the temperature range of -15 to +40℃
is 90~IO0 ■Melt 70-rate 300g/10m1n or more.

■Results of melting point measurement in thermal analysis using differential scanning calorimetry are peak temperature +30~+80℃, melting end temperature +40~
+90°C, and the melting heat energy from +25°C to the melting end temperature is 50 cal/g or less.

Since the copolymer used as the fitting material of the present invention usually has a glass transition temperature of 115° C. or lower, it is in a state where it exhibits rubber-like elasticity and is easily deformed while the ski boot is in use, so that it comfortably holds the foot. That is, as shown in FIG. 4, the storage modulus of thermoplastic resins generally increases rapidly when cooled beyond the glass transition temperature Tg, but the copolymer constituting the fitting material of the present invention Since the glass transition temperature is lower than the expected lowest temperature on the outer surface of the inner boot, about -15° C., when the ski boot is used, it exhibits rubber-like elasticity and comfortably holds the foot when the ski boot is used.

In addition, the copolymer constituting the fitting material of the present invention is usually ~! Shore hardness (A
type) is within the range of 90-10. That is, the curve showing the relationship between the hardness and temperature passes through the range shown by diagonal lines in FIG.

Therefore, the fitting material of the present invention does not cause pain to the foot when used, and moreover, allows sufficient force to be transmitted between the foot and the ski boot.

Furthermore, since the copolymer constituting the fitting material of the present invention usually has a melt flow rate of 300 g/10 m1n or more, the fitting material can flow sufficiently when fitting ski boots, and the periphery of the fitting material in particular gradually melts. It is thinner and provides a good fit.

Furthermore, when the melting point is measured by thermal analysis using differential scanning calorimetry, data as shown in FIG. 6 is generally obtained. The diagonal line in FIG. 5 indicates the peak temperature, and T3 indicates the melting end temperature. The copolymer constituting the fitting material of the present invention usually exhibits a peak temperature T of +30 to +80°C and a melting end temperature T of +40 to +90°C (these values are determined by a heating rate of 5°C/min). ), there is no risk of accidents such as deformation of the nonyl due to the heat during the fitting process, and the fitting condition will be damaged due to the fitting material becoming fluidized by body temperature during use. Not at all.

In addition, the copolymer constituting the fitting material of the present invention usually has a melting heat energy of 55°C from +25°C to the melting end temperature.
Since it is 0 cal/g or less, the fitting process can be performed in a short time (for example, within about 30 minutes) even at a temperature below the heat resistant temperature of the fitting material.

"Operation" The fitting material of the present invention is melted and softened by heating means such as a heater. In this melted and softened state, it flows and adapts to the shape of the foot.

Thereafter, the fitting material is cooled to fix its shape and is ready for use.

The fitting material of the present invention does not become fluidized at body temperature, so it does not deform during use.

In addition, in the fitting material of claim 2, physical properties such as hardness and fluidization temperature can be appropriately adjusted to be optimal as a fitting material by adjusting the amount of liquid plasticizer added.

"Example J A pad having the structure shown in FIGS. 1 and 2 was made using the fitting material of the present invention.

This pad 1 has a roughly figure-eight shape in which a disc-shaped instep contact portion 2 and a disc-shaped shin contact portion 3 are connected.

In this pad 1, the fitting material 5 is a thick bag body 4.
A heater 6 is arranged within the fitting material 5.

This heater 6 is connected to an external power source 7.

As shown in Fig. 3, this pad l is inserted into the outer surface of the inner boot of the ski boot so that the instep contact part 2 contacts the instep of the foot 8, and the shin contact part 3 contacts the shin part of the foot. It is set and inserted into the shell 9 in this state.

The pad with such a structure was filled with a fitting material having the characteristics shown in Table 1.

A pad made of these fitting materials 5 was subjected to fitting treatment as follows and used.

First, attach the pad L to the inner boot 10 using the shell 9.
It was housed inside. Next, put foot 8 into the inner boots lO,
A power source 7 was connected to the heater 6 of the pad 1. and about 10
Electricity was applied for a minute to melt the fitting material 5. After this, the power was turned off, the legs were removed, and the legs were left at room temperature to cool.

Next, the padded pad that was fitted in this way
・was used at a ski resort.

For comparison purposes, a paraffin wax fitting material having the properties shown in Table 1 and a hard ethylene-vinyl acetate copolymer fitting material were subjected to similar tests.

As a result, it was confirmed that all the pads made of the fitting materials of Examples 1 to 4 could be fitted in a short time. This seems to be because the amount of heat of fusion is small. Further, in Examples 1 to 4, a good fit was obtained and the fitting process was easy.

In particular, the fitting material to which DOP was added (Example 3.
4) The fitting process was easy.

On the other hand, the comparative example required a considerable amount of time for fitting.

Furthermore, when pads made of these fitting materials were used, those of Examples 1 to 4 did not cause any pain to the feet even when used for a long period of time, and moreover, it was possible to perform sharp ski operations.

On the other hand, Comparative Example 1 made of paraffin wax was brittle, did not exhibit elastomer-like behavior, and caused foot pain in a short period of time. In addition, the fitting material of Comparative Example 2 was hard and caused foot pain in a short period of time.

Then, when the pad L was taken out and observed, it was found that Example 1
The peripheral edge of the fitting material 5 of No. 4 to 4 was gradually stretched thinner. This seems to be because the fitting materials 5 of Examples 1 to 4 have good fluidity and can easily flow into the gap between the fitting materials 5 and the thick bag 4.

Next, when the fitting materials 5 of Examples 1 to 4 were taken out and heated to their peak temperature, these resins showed a thixotropic phenomenon, deforming when force was applied and becoming gel-like again when the force was removed. Ta.

"Effects of the Invention" As explained above, the fitting material of claim 1 is mainly composed of vinyl acetate, an acrylic component or a vinyl acetate-acrylic component, and ethylene, and the proportion of components other than ethylene is 20% by weight or more. And since it is made of a copolymer with a number average molecular weight of 30,000 or less, it will not become fluid at body temperature and will reliably maintain its fitted shape even after long periods of use. Therefore, even if the fitting material is used for a long period of time, it can always ensure good transmission of force from the foot to the ski boot. In addition, since it has appropriate rubber elasticity, it does not cause pain to the feet after long periods of use, and is comfortable to use. In addition, this fitting material can perform fitting with less thermal energy and can be retried any number of times, making the fitting process easier. Furthermore, since this fitting material has low crystallinity, when used with a heater embedded therein, the entire fitting material can be uniformly softened and a good fitting can be achieved.

According to the fitting material of the second aspect, by appropriately adjusting the amount of the liquid plasticizer added, it is possible to obtain a fitting material with better usability and ease of handling during fitting processing.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an example of a pad using the fitting material of the present invention, Fig. 2 is a longitudinal sectional view of the pad, Fig. 3 is a perspective view showing how the pad is used, and Fig. 4 is a cross-sectional view showing an example of a pad using the fitting material of the present invention. A graph showing the general relationship between the temperature and storage modulus of a copolymer. Figure 5 is a graph showing the range of Shore hardness (Type A) normally exhibited by the fitting material of the present invention. Figure 6 is a graph showing the range of Shore hardness (type A) that the fitting material of the present invention normally shows. It is a graph showing general data obtained by the measurement method.

Claims (2)

[Claims] (1) A copolymer mainly composed of vinyl acetate, an acrylic component, or a vinyl acetate-acrylic component and ethylene, the proportion of components other than ethylene is 20% by weight or more, and the number average molecular weight is 30,000 or less. A fitting material for ski shoes consisting of: (2) The fitting material for ski boots according to claim 1, further comprising a liquid plasticizer.