JPH04259466A - Orthosis sheet and orthosis - Google Patents

Abstract

PURPOSE:To ensure the easy manufacture of an orthosis, maintain a good balance between fixing and movable characteristics at a joint or the like in use, and obtain an orthosis and an orthosis sheet having excellent mounting characteristics and durability. CONSTITUTION:Stylenic thermoplastic elastomer [surface hardness JIS-A (JIS K6301): 87, tensile breaking strength (ASTM D 638): 280kg/cm<2> and tearing strength (ASTM D 624): 50kg/cm] is extrusion molded, thereby forming a sheet for an orthosis. The sheet so formed is softened under exposure to a temperature of 180 deg.C for 10 minutes, and molded in a manual drawing process via a plaster positive mold for an ankle-foot orthosis.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides fixation and movability that can be suitably used as trunk braces, upper limb braces, and lower leg braces used in surgery, orthopedics, and rehabilitation, particularly for short and long legs, knee braces, etc. The present invention relates to an orthosis and an orthosis sheet that have excellent wearability on the body and durability.

0002

[Prior Art] Metal, leather, and cloth have been used as materials for orthotics since ancient times, but they have drawbacks such as being heavy, having a poor appearance, rusting, and becoming unclean. With the progress of molecular technology, thermoplastic resins that solve the above-mentioned drawbacks have been widely used. Thermoplastic resin materials are lightweight, have a good appearance, do not rust, are stain resistant and clean, are flexible, can be shaped to some extent by heating, and are easy to manufacture. This method has the advantage of being able to obtain a shape that accurately matches a positive model such as plaster cast from a patient.

[0003] A method for manufacturing an orthosis whose main material is thermoplastic resin is to cover a positive model taken from a patient with a thermoplastic resin sheet that has been heated and softened in an oven, and to insert a thermoplastic resin sheet between the positive model and the thermoplastic resin sheet. There are two methods: vacuum forming, which involves sucking in air from the patient and molding the mold, and manual molding, which involves covering a positive model taken from a patient with a thermoplastic resin sheet that has been heated and softened in an oven, and then squeezing it by hand to form the mold. be.

[0004] Therefore, the materials used for this are:
In addition to inherent properties such as tensile properties, bending properties, tear strength, and bending resistance that are required when worn on the body, it is desired that the material be easy to handle during manufacturing, especially during heat softening. Taking these into consideration, the thermoplastic resin used varies depending on the patient's symptoms and the site of application, but ultra-high molecular weight polyethylene, high-density polyethylene, polypropylene, etc. are mainly used.

[0005]

[Problems to be Solved by the Invention] However, when comparing the mechanical properties of thermoplastic polyolefin resins such as polypropylene and metals, metals have greater strength, and moreover, when used as braces, joints are required. However, when thermoplastic polyolefin resin is used in parts such as joints, its strength is weak and fixation is insufficient, and it is difficult to use as a joint that requires mobility. Functionality is also not sufficient. For example, shoehorn-type short leg orthoses made of thermoplastic resin are used not only for walking but also for activities of daily living; There are problems such as discomfort during movement due to misalignment with the target joint axis, and damage due to repeated stress.

[0006] When the resin sheet is made thicker in order to increase its strength, the fixation of the ankle joints and the like is improved, but not only does the movability of the parts corresponding to the joints become lost, but also the weight increases and the feeling of wearing is deteriorated. Dissatisfaction grows. In addition, the bulkiness of the shoes makes it impossible to wear commercially available ready-made shoes. Therefore, in order to satisfy the conflicting requirements of fixity and mobility in a well-balanced manner, there was a need for a material that is flexible and elastic, and that is easy to manufacture.

In view of the above circumstances, the present invention provides an orthosis and an orthosis sheet that are easy to manufacture, have an excellent balance between fixation and mobility of joints, etc. during use, and are excellent in wearability and durability. The purpose is to

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention has a surface hardness JIS-A (JIS K6
301) is 30-100, tensile strength at break (ASTMD
638) is 70 kg/cm2 or more and tear strength (A
An orthosis sheet formed of a styrene thermoplastic elastomer having a STM D 624) of 30 kg/cm or more and a surface hardness JIS-A (JIS K 6301) of 30 to 1.
00, tensile strength at break (ASTM D 638) is 7
0 kg/cm2 or more and tear strength (ASTM D
624) is made of a styrene-based thermoplastic elastomer with a weight of 30 kg/cm or more, and is capable of being attached to a human body.

According to the present invention, the excellent moldability, chemical properties, and mechanical properties of a styrenic thermoplastic elastomer are utilized, and the surface hardness, tensile strength at break, and tear strength are set within specific ranges. Accordingly, it is possible to obtain a brace and a brace sheet that are easy to manufacture, have an excellent balance between fixation and mobility of joints, etc. during use, and have excellent wearability and durability.

The styrenic thermoplastic elastomer of the present invention has a chemical structure in which the hard segment is composed of a crystalline phase of a monovinyl-substituted aromatic hydrocarbon polymer, and the soft segment is composed of an amorphous conjugated diene having a low glass transition point (Tg). It is a multi-block copolymer using a polyester polymer.

[0011] Various polymers of monovinyl-substituted aromatic hydrocarbons in the hard segment can be mentioned;
Particularly suitable is polystyrene. Polybutadiene or polyisoprene is suitable as the conjugated diene polymer for the soft segment. As an example, styrene-butadiene-styrene block copolymer (SBS) using polybutadiene in the soft segment, styrene-isoprene-styrene block copolymer using polyisoprene in the soft segment, or hydrogenating the butadiene portion of SBS. Examples include styrene-ethylene-butylene-styrene block copolymer (SEBS) in which the double bond portion in the main chain is saturated.

[0012] By selecting the type of these soft segments and the ratio of hard segments to soft segments, elastomers with various properties suitable for the purpose of the present invention can be obtained.

In order to achieve the object of the present invention, the styrenic thermoplastic elastomer of the present invention can not only be used alone, but also be blended with various polymers so that the styrenic thermoplastic elastomer has a weight ratio of 70%. % or more of the main component may be used.

For example, in order to lower the molding temperature of the orthosis sheet and adjust the fluidity of the resin during the process, it is possible to blend a polystyrene-based thermoplastic elastomer as a main component and a thermoplastic polyolefin-based resin as a subsidiary component. You can also do it. In this case, as the thermoplastic polyolefin resin, for example, an acid anhydride-containing olefin resin obtained by copolymerizing or graft polymerizing an unsaturated dicarboxylic acid anhydride to a polyolefin or olefin copolymer having good compatibility with polystyrene or a polyolefin. Polymers and the like can be used.

In the styrenic thermoplastic elastomer of the present invention, the type of polymer of the soft segment or the ratio of the hard segment to the soft segment is selected,
By controlling the softening point, it is possible to design the processing temperature for injection molding, extrusion molding, and other processing methods within a certain range. This is particularly convenient for setting the temperature for heating and softening during molding, in which a positive model taken from a patient is covered with a polystyrene thermoplastic elastomer sheet heated in an oven.

The lower the softening point of the styrene-based thermoplastic elastomer in the present invention, the more convenient it is to work during the manufacture of the orthosis; Plastic deformation and local flow may occur during disinfection, sterilization, and cleaning of the orthosis. Further, when the softening point of the styrene thermoplastic elastomer is higher than 190°C, the heat resistance of the orthosis is improved, but workability and safety are impaired. Taking into account the heat resistance of the orthosis and the workability during manufacturing, the desirable range is 150.
℃~180℃.

The styrene-based thermoplastic elastomer used in the present invention is a material that is flexible and has excellent rubber elasticity, but its rebound modulus and flexural modulus are particularly poor due to the effects of external forces applied during motions such as walking. This is a measure of the resilience of deformation caused by work. These elastic properties should be determined depending on the patient's disease site, degree of deformity due to the disease, age, physical strength, etc.

Surface hardness JIS-A (JIS K) required for the styrenic thermoplastic elastomer in the present invention
6301) is determined depending on the degree of correction of deformation of the affected area or local fixation, support, or load relief of the affected area, but it is required to be 30 to 100, preferably 35 to 90.

The tensile breaking strength (ASTM D 638) and tear strength (ASTM D 624) of the styrene thermoplastic elastomer used in the present invention are reflected in the durability of the orthosis, and are selected taking into consideration the patient's age, physical strength, gender, etc. However, the tensile strength at break is 70 kg/c.
m2 or more and tear strength of 30 kg/cm or more are required. Note that it is practically desirable that the tensile strength at break is 300 kg/cm 2 or less, and the tear strength is 200 kg/cm or less.

The orthosis formed of the styrene thermoplastic elastomer of the present invention can be functionally used as a short leg orthosis applied around the ankle joint as an adaptation site to the body, but is not limited thereto. By designing the mechanical properties, it can function as an upper limb orthosis or hand orthosis, and with a more rigid design, it can function as a trunk orthosis.

The orthosis and orthosis sheet molded from the styrenic thermoplastic elastomer of the present invention include:
Heat stabilizers, antioxidants, and pigments may also be added. Also,
Fiber reinforcements such as glass fibers, metal fibers, carbon fibers, filler reinforcements such as talc, calcium carbonate, and mica may also be added.

The additives, reinforcing agents, etc. mentioned above may be mixed with the styrenic thermoplastic elastomer of the present invention by any known method. For example, the granules of each component are mixed in a V-type blender, Henschel mixer, super mixer, or kneader, and then directly molded into sheets or injection molding, or mixed in an extruder, kneader, intensive mixer, etc. to form chips, This may be molded. In any case, an appropriate method may be adopted depending on the resin composition ratio and the desired shape and properties of the product.

[0023] The method for manufacturing the orthosis sheet of the present invention is generally carried out by extrusion molding using a sheet extruder. The method for manufacturing braces from brace sheets is as follows:
The orthosis sheet is heated and softened, placed over a positive model, etc., and air is sucked between the orthosis sheet and the positive model, or fluid pressure, human power, or mechanical force is applied from the outer surface of the orthosis sheet to make them adhere tightly. do. Furthermore, the orthosis can be formed by various molding methods such as blow molding, press molding, and vacuum forming before the orthosis sheet extruded by a sheet extruder is cooled, or by molding methods such as injection molding. It may also be directly molded. In this case, it is also possible to take a ready-made shape that has been given a certain degree of shape as an orthosis in advance, and modify the wearability when applying it to a patient.

The thickness of the orthosis sheet and the orthosis is not particularly limited, but is 1 to 5 mm, preferably 2 to 5 mm.
4 mm is suitable for practical use.

[0025]

[Examples] The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited thereto.

Example 1 Styrenic thermoplastic elastomer [Surface hardness JIS-A
(JIS K 6301) 87, tensile strength at break (A
STM D 638) 280 kg/cm2, tear strength (ASTM D 624) 50 kg/cm], JSR-TR2000 (manufactured by Japan Synthetic Rubber Co., Ltd.) chips were extruded using a sheet extruder with a die width of 600 mm, and the size was 500 mm x 500 mm x thickness. A 3 mm sheet was obtained.

[0027] This sheet was heated in an oven at 180°C for 10
When the sheet was heated for several minutes to soften it and then hand-wrapped using a plaster-positive model for short leg orthosis, the sheet did not sag when taken out of the oven and was relatively easy to handle.
．． Orthoses with a thickness in the range of 5 mm were obtained with good reproducibility.

[0028] When this orthosis was modified and trimmed and applied to a patient with moderate equinus varus foot, proper fixation improved the dragging of the tip of the foot, stabilized the gait, and enabled elastic movement. Because of his gender, crouching became easier. In addition, you can wear commercially available shoes with the orthosis attached.
It is now possible to go out.

Example 2 Styrenic thermoplastic elastomer (surface hardness JIS-A
(JIS K 6301) 75, tensile strength at break (A
STM D 638) 170 kg/cm2, tear strength (ASTM D 624) 45 kg/cm) chips of Lavalon SE7400BN (manufactured by Mitsubishi Yuka Corporation) were extruded using a sheet extruder with a die width of 600 mm, and the size was 500 mm x 500 mm x thickness 3 mm. I got a sheet of

[0030] This sheet was heated in an oven at 160°C for 10
When heated for 20 minutes to soften it and molded it by vacuum forming in a pediatric plaster positive model for short leg orthosis, it was found to be 2 to 2.5 m long.
Orthoses with a thickness in the range of m were obtained with good reproducibility. When this pediatric orthosis was trimmed and worn on a patient with mild equinus varus, it was found to be more flexible than the orthosis of Example 1 and could be easily applied to children.

[0031]

[Effects of the Invention] As is clear from the above explanation, according to the present invention, by using a styrenic thermoplastic elastomer that has physical properties under specific conditions and has a good balance of elasticity and flexibility. The present invention makes it possible to provide an orthosis and an orthosis sheet that are easy to manufacture and satisfy the conflicting performance requirements of fixation and mobility.

Claims (2)

[Claims] [Claim 1] Surface hardness JIS-A (JIS K
6301) is 30-100, tensile strength at break (ASTM
A sheet for an orthosis, characterized in that it is formed into a sheet of a styrene thermoplastic elastomer having a tensile strength (D 638) of 70 kg/cm2 or more and a tear strength (ASTM D 624) of 30 kg/cm or more. [Claim 2] Surface hardness JIS-A (JIS K
6301) is 30-100, tensile strength at break (ASTM
1. An orthosis which is made of a styrene-based thermoplastic elastomer and has a tensile strength (D 638) of 70 kg/cm2 or more and a tear strength (ASTM D 624) of 30 kg/cm or more, so that it can be worn on a human body.