JPH09202857A - Impact-absorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an impact-absorbing material excellent in stress relaxation characteristics. SOLUTION: This impact-absorbing material comprises a thermoplastic material containing a polymeric organic material and a softening agent, and has a JIS A hardness of 0-25 deg. (measured with a JIS K 6301 standard S scale), a compression permanent set of <=50% (measured according to JIS K6301 standard) at 100 deg.C and an MFR of >=10g/10min at 230 deg.C. The impact-absorbing material preferably comprises 100 pts.wt. of the polymeric organic material, 50-500 pts.wt. of the softening agent and 10-250 pts.wt. of a polyphenylene ether. The difference between the solubility parameter of the polymeric organic material and that of the softening agent is <=3.0. The polymeric organic material is a polymer obtained by hydrogenating a copolymer containing a polystyrene block and a polybutadiene block. The softening agent is preferably selected from naphthenic, paraffinic and polyisobutylene oils.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorbing material made of a thermoplastic material, and more specifically, a cushioning material such as furniture, bedding, interior material for vehicles, which needs a stress relaxation action against various stimuli. , A building interior material, electric / electronic related products, and other shock absorbing materials that are preferably used for shock absorbing various constituent members.

[0002]

2. Description of the Related Art Conventionally, shock absorbing materials used for various purposes have low hardness, have improved flow characteristics, have excellent set resistance, and further improve vibration absorption and compression characteristics. It is strongly demanded to improve the shock absorbing property and its durability due to various physical properties.

Heretofore, as a material used for the shock absorbing material, polymer foams such as polyurethane foam and PVC foam, and thermosetting materials such as silicone gel and polynorbornene have been known. The polymer foam is used, for example, in cushions, which are the required shock absorbing characteristics of cushions, such as the fit of the body when sitting, the stability of holding the body, the overall sitting feeling, and the feeling of the body after sitting for a long time. Pain and fatigue in the body are not enough. As described above, the reason why the conventional polymer foams and thermosetting materials do not have sufficient impact absorption is that the above-mentioned various physical properties of the material are not balanced at a high level and are not satisfied. it is conceivable that.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above facts, and has a low hardness as a material, a low compression set at high temperature (excellent in settling resistance), and a blended low molecular weight compound. An object of the present invention is to provide a shock absorbing material excellent in shock absorbing property and its durability by using a component capable of suppressing bleeding.

[0005]

The shock absorbing material of the present invention comprises:
A shock absorber made of a thermoplastic material containing a high molecular weight organic material and a softening agent, and having a hardness of JIS K6301 standard A.
The scale is 0 ° to 25 °, the compression set at 100 ° C is 50% or less according to JIS K6301, and the MFR at 230 ° C is JIS K721.
It is characterized by being 0 g or more and 10 g / 10 minutes or more.

The thermoplastic material contains 100 parts by weight of a high molecular weight organic material and 50 to 500 parts by weight of a softening agent, and the difference in solubility parameter between the high molecular weight organic material and the softening agent is 3.0. The following is preferable.

The thermoplastic material preferably contains 10 to 250 parts by weight of polyphenylene ether.

The polymer organic material used in the impact absorbing material of the present invention comprises at least one polymer block mainly containing a vinyl aromatic compound and at least one polymer block mainly containing a conjugated diene compound. Is a hydrogenated block copolymer obtained by hydrogenating the following block copolymer having an average molecular weight of 150,000 to 400,000.
It is characterized by being 0.

Further, the softening agent is one or more selected from naphthenic oils, paraffinic oils or polyisobutylene oils, and has an average molecular weight of 450 to 5,000. .

The tan δ of the thermoplastic material is 0.
It is characterized by being 05 to 1.0.

The impact absorbing material of the present invention is obtained by combining a polymeric organic material and a softening agent to obtain a material having a low hardness, good shape following property and adhesiveness, and softening with the polymeric organic material. The difference in the solubility parameter of each agent is 3.0
By the following, the compatibility of the material is improved, bleeding of low molecular components can be prevented, the compression set is small (improvement in settling resistance), the compression stress is small,
Since it is excellent in vibration absorption, excellent shock absorption and its durability can be achieved.

Further, since this thermoplastic material has a good releasability, even if it is formed into a sheet and then laminated and stored, the materials do not stick to each other and can be peeled off smoothly. Even after that, the productivity of the shock absorber does not decrease.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

In the present invention, the high molecular weight organic material has a number average molecular weight of 20,000 or more, particularly 30,0.
00 or more, especially 40,000 or more of thermoplastic polymer organic materials are preferable, and for example, various thermoplastic elastomers such as styrene (butadiene styrene, isoprene styrene, etc.), ester, amide, urethane, etc., and Hydrogenated or other modified products thereof, styrene type, ABS type, olefin type (ethylene type, propylene type, ethylene propylene type, ethylene styrene type, propylene styrene type, etc.), vinyl chloride type, acrylic acid ester type (acrylic acid Methyl type, etc., Methacrylic acid ester type (methyl methacrylate type, etc.) Carbonate type, acetal type, nylon type, halogenated polyether type (chlorinated polyether type, etc.), halogenated olefin type (tetrafluoroethylene type, Fluorinated-ethylene chloride type, fluorinated ethylene Propylene type), cellulose type (acetyl cellulose type, ethyl cellulose type, etc.), vinylidene type, vinyl butyral type, alkylene oxide type (propylene oxide type, etc.) and other thermoplastic resins, and rubber modified products of these resins, etc. To be

As a concrete thermoplastic polymer organic material, a material having a hard block such as a crystal structure or an agglomerate structure and a soft block such as an amorphous structure together is particularly preferable. Preferably, specifically, the following are mentioned.

A block copolymer of crystalline polyethylene obtained by hydrogenating a block copolymer of polybutadiene and a butadiene-styrene random copolymer, and an ethylene / butylene-styrene random copolymer.

Obtained by hydrogenating a block copolymer of polybutadiene and polystyrene or a block copolymer of polybutadiene or ethylene-butadiene random copolymer and polystyrene, for example, diethylene of crystalline polyethylene and polystyrene Among them, block copolymers, styrene-ethylene / butylene-styrene triblock copolymers, and the like, among them, styrene-ethylene / butylene-styrene block copolymers.

A block copolymer in which crystalline polyethylene is linked to one end or both ends of an ethylene / butylene copolymer.

Ethylene-propylene rubber. Among these, obtained by hydrogenating a block copolymer, which is specifically mentioned, consisting of at least one polymer block mainly containing a vinyl aromatic compound and at least one polymer block mainly containing a conjugated diene compound. Hydrogenated block copolymer having an average molecular weight of 150,00
It is preferably from 0 to 400,000. That is,
A block copolymer composed of at least one polymer block mainly containing a vinyl aromatic compound (1 segment) and at least one polymer block mainly containing a conjugated diene compound (1 segment) is hydrogenated. The block copolymer having at least two polymer blocks containing a vinyl aromatic compound as a main component and at least one polymer block containing a conjugated diene compound as a main component (for example, styrene-butadiene) is preferable. Hydrogenated block copolymers obtained by hydrogenating styrene block copolymers) are more preferable. The hydrogenated block copolymer represented by this styrene-ethylene / butylene-styrene block copolymer has an average molecular weight of 15
When it is less than 10,000, the compression set is deteriorated and the durability of the impact absorbing effect is lowered, and when it exceeds 400,000, the fluidity of the material is lowered and the moldability is deteriorated. Therefore, the average molecular weight is It is preferably within the above range.

The content of the amorphous styrene block is 10
It is desirable that the amount is in the range of ˜70 wt%, preferably 15-60 wt%. The glass transition temperature (Tg) of the amorphous styrene block portion is 60 ° C or higher, preferably 80 ° C.
The above is desirable. Further, the polymer of the portion connecting the amorphous styrene blocks at both ends is also preferably an amorphous one, and examples thereof include an ethylene-butylene copolymer, a butadiene polymer, and an isoprene polymer. It may be a block or random copolymer of these.

These various kinds of thermoplastic high-molecular organic materials are mainly used alone, but two or more kinds may be used as a blend.

As the softening agent used in the present invention, it is preferable to use a low molecular weight material having a number average molecular weight of less than 20,000. Physically, the viscosity at 100 ° C. is 5 × 10 ⁵ centipoise. Below, in particular, 1 × 10
It is preferably ⁵ centipoise or less, and from the viewpoint of molecular weight, the number average molecular weight is preferably less than 20,000, especially 10,000 or less, particularly preferably 5,000 or less. As such a softening agent, usually, a liquid or liquid material at room temperature is preferably used. Further, either a hydrophilic or hydrophobic softener can be used. The softener is not particularly limited, but the following are suitable. This softening agent includes various types of rubber or resin softening agents such as mineral oil type, vegetable oil type and synthetic type. Examples of the mineral oil-based oil include process oils such as naphthene-based oil and paraffin-based oil. Vegetable oils include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil,
Examples include wood wax, pine oil and olive oil.
Among them, one or more selected from mineral oil-based paraffinic oils, naphthene-based oils, and polyisobutylene-based oils, having an average molecular weight of 4
It is preferably from 50 to 5,000. In the oil preferably used as the softening agent, if the average molecular weight is less than 450, the compression set is deteriorated and the durability of the shock absorbing effect is reduced, and if it exceeds 5,000, the surface of the obtained shock absorbing material is deteriorated. Since stickiness occurs, the average molecular weight is preferably within the above range.

One of these softeners may be used alone, or two or more thereof may be used in combination as long as they have good compatibility with each other.

The blending amount of these softening agents is 50 to 500 parts by weight, preferably 50 to 300 parts by weight, based on 100 parts by weight of the high molecular weight organic material. The amount is 5
If it is less than 0 parts by weight, a sufficiently low hardness cannot be achieved, and the flexibility of the material becomes insufficient, and if it exceeds 500 parts by weight, bleeding of the softening agent tends to occur, and the mechanical strength of the material is Any of them is not preferable from the viewpoint of impact absorption effect.

In order for the shock absorbing material of the present invention to exhibit preferable flexibility, vibration damping property and durability, the physical properties are such that the hardness is 0 ° to 25 ° on the JIS K6301 standard A scale.
And the compression set at 100 ° C. is JIS K6.
It is required to be 50% or less in the 301 standard and 10 g / 10 minutes or more in the JIS K7210 standard at 230 ° C.

The hardness of the impact absorbing material of the present invention is JIS K6.
When the hardness exceeds 301 in the 301 standard A scale, the hardness of the material becomes too high to obtain shock absorption, and when the compression set at 100 ° C exceeds 50% in JIS K6301, the material deforms with time and the impact Absorbability may decrease, and if the MFR at 230 ° C. is less than 10 g / 10 minutes according to JIS K7210 standard, the workability decreases and the productivity deteriorates.

Ta of the thermoplastic material for impact absorbing material of the present invention
nδ is preferably 0.05 to 1.0, and more preferably 0.10 to 0.80. If tan δ is less than 0.05, the impact absorbency will be poor, and if it exceeds 1.0, the temperature dependence of the material will be poor, and both are not preferred.

In order to have the above-mentioned properties, the polymer organic material constituting the thermoplastic material in the present invention preferably has a three-dimensional continuous network skeleton structure, and the formed three-dimensional continuous network skeleton structure is formed. Has an average diameter of its skeleton of 5
0 μm or less, preferably 30 μm or less, the average diameter of the cells (mesh) is 500 μm or less, preferably 300 μm or less, and the volume fraction of the high-molecular organic material is [volume of high-molecular organic material / (volume of high-molecular organic material) (Volume + volume of softener)] ×
When defined as 100 (%), the volume fraction of the high molecular weight organic material is preferably 50% or less, particularly preferably 33% or less.

Further, in order to obtain a shock absorber made of a thermoplastic material containing a large amount of a softening agent and a smaller amount of a polymeric organic material, the solubility parameter value δ = (of each of the softening agent and the polymeric organic material used. It is preferable to select both materials so that the difference of ΔE / V) ^1/2 (ΔE = molar evaporation energy, V = mol volume) is 3.0 or less, preferably 2.5 or less. If this difference exceeds 3.0, from the viewpoint of the compatibility of both materials, it is difficult to retain a large amount of the softening agent, which is an obstacle to lowering the elasticity of the obtained thermoplastic material, and bleeding of the softening agent is likely to occur. Therefore, it is not preferable because there is a risk that the shock absorbability will decrease.

The impact absorbing material of the present invention may contain a polyphenylene ether resin for the purpose of improving the compression set of the material, sustaining the impact absorbing effect, and improving the durability of the impact absorbing material. . The polyphenylene ether resin used here is a homopolymer composed of a bonding unit represented by the following formula or a copolymer containing the bonding unit.

[0031]

Embedded image

In the formula, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a halogen atom or a hydrocarbon group.

As the polyphenylene ether resin, known resins can be used. Specifically, for example, poly (2,2)
6-dimethyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether), poly (2,6-diphenyl-1,4-phenylene ether), poly (2- Methyl-6-phenylene-1,
4-phenylene ether), poly (2,6-dichloro-)
1,4-phenylene ether) and the like.
A polyphenylene ether copolymer such as a copolymer of 2,6-dimethylphenol and a monovalent phenol (for example, 2,3,6-trimethylphenol or 2-methyl-6-butylphenol) can also be used. Among them, poly (2,6-dimethyl-1,4-phenylene ether) and a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol are preferable, and further,
Poly (2,6-dimethyl-1,4-phenylene ether) is preferred.

The blending amount of the polyphenylene ether resin is as follows:
It can be suitably selected within the range of 10 to 250 parts by weight with respect to the thermoplastic material. If the amount exceeds 250 parts by weight, the hardness of the thermoplastic material becomes high, the flexibility may be lost, and the impact absorption may decrease. If the amount is less than 10 parts by weight, the improvement effect obtained by compounding is insufficient, Neither is preferable.

If necessary, the shock absorbing material of the present invention may further contain the following fillers.
In other words, clay, diatomaceous earth, silica, talc, barium sulfate, calcium carbonate, magnesium carbonate, metal oxide, mica, graphite, flaky inorganic fillers such as aluminum hydroxide, various metal powders, wood chips, glass powder, ceramics Granular or powdery solid fillers such as powder, granular or powdery polymer, and other various natural or artificial short fibers and long fibers (eg, straw, wool, glass fiber, metal fiber, various other polymer fibers, etc.) Can be blended.

Further, it is possible to reduce the weight by blending a hollow filler, for example, an inorganic hollow filler such as a glass balloon or a silica balloon, or an organic hollow filler made of polyvinylidene fluoride or a polyvinylidene fluoride copolymer. Furthermore, it is also possible to mix various foaming agents to improve various physical properties such as weight reduction.
It is also possible to mechanically mix gas during mixing or the like.

In addition to the above components, the impact absorbing material of the present invention may be used in combination with known resin components and additives in order to improve various properties.

As the resin component, for example, a polyolefin resin or a polystyrene resin can be used in combination. By adding these, the workability of the shock absorber,
The heat resistance can be improved. Examples of the polyolefin resin include polyethylene, isotactic polypropylene, and a copolymer of propylene with a small amount of other α-olefin (eg, a propylene-ethylene copolymer and a propylene / 4-methyl-1pentene copolymer). ,
Examples thereof include poly (4-methyl-1pentene) and polybutene-1. When isotactic polypropylene or its copolymer is used as the polyolefin resin, its MFR (JIS K7210) is 0.1 to 5
A range of 0 g / 10 min, particularly 0.5 to 30 g / 10 min can be suitably used.

As the polystyrene resin, any resin obtained by a radical polymerization method or an ionic polymerization method can be preferably used as long as it is obtained by a known production method. The number average molecular weight of the polystyrene resin is 5,000-5
00,000, preferably 10,000-200,00
0 and a molecular weight distribution [ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / M
n)] is preferably 5 or less.

Examples of the styrene resin include polystyrene and styrene having a styrene content of 60% by weight or more.
Butadiene block copolymer, rubber reinforced polystyrene,
Examples thereof include poly α-methyl styrene and poly p-tertiary butyl styrene, and these may be used alone or in combination of two or more. Further, a copolymer obtained by polymerizing a mixture of monomers constituting these polymers can also be used.

The polyolefin resin and polystyrene resin may be used in combination. When these resins are added to the impact absorbing material of the present invention, the hardness of the obtained material tends to be higher when the polystyrene resin is used in combination as compared with the case where only the polyolefin resin is added. Therefore, the hardness of the resulting shock absorbing material can be adjusted by selecting these compounding ratios. In this case, the ratio of polyolefin resin / polystyrene resin is 9
It is preferable to select from the range of 5/5 to 5/95 (weight ratio).

When these resin components are used in combination, they should be used within a range that does not impair the effects of the present invention, and the compounding amount is 0 to 100 with respect to 100 parts by weight of the polymer organic material.
It is preferred that the amount is about parts by weight. If the blending amount of the resin component exceeds 100 parts by weight, the hardness of the obtained impact absorbing material becomes too high, the flexibility is lost, and the impact absorbing property is lowered, which is not preferable.

As other additives, if necessary,
Flame retardant, antibacterial agent, hindered amine light stabilizer, UV absorber, antioxidant, inorganic filler, colorant, silicone oil, coumarone resin, coumarone-indene resin, phenol terpene resin, petroleum hydrocarbon, rosin derivative, etc. Various tackifiers (Tackifier), various adhesives such as Rheostomer (trade name: Riken Vinyl Co., Ltd.), Hibler (trade name: Kuraray Co., Ltd., block in which polystyrene blocks are connected to both ends of vinyl-polyisoprene block) Copolymer) or Nosolex (trade name: manufactured by Nippon Zeon Co., Ltd., polynorbornene obtained by ring-opening polymerization of norbornene) or the like, which can be used in combination with a thermoplastic elastomer or resin for improving vibration damping property.

The method for producing the impact absorbing material of the present invention is not particularly limited, and known methods can be applied. For example, the above-mentioned materials and, if desired, additive components are melt-kneaded using a heat kneader, for example, a single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer, a Brabender, a kneader, a high-shear mixer, or the like. Further, if desired, a cross-linking agent such as an organic peroxide, a cross-linking aid, or the like is added, or these necessary components are mixed at the same time, and the mixture is heated and melt-kneaded, so that it can be easily produced.

Further, a thermoplastic material prepared by kneading a high molecular weight organic material and a softening agent is prepared in advance, and this material is used as one or more high molecular weight organic materials of the same kind or different kinds from those used here. It can be manufactured by further mixing.

In the impact absorbing material of the present invention, it is possible to add a crosslinking agent such as organic peroxide, a crosslinking aid and the like to effect crosslinking.

Here, as the cross-linking agent which can be added for the partial cross-linking, organic peroxide is preferably mentioned, and specifically, for example, 2,5-dimethyl-2,5-di (t
-Butylperoxy) -hexane, 2,5-dimethyl-
2,5-di (benzoylperoxy) -hexane, t-
Butyl peroxybenzoate, dicumyl peroxide, t-butyl cumyl peroxide, diisopropyl benzohydroperoxide, 1,3-bis- (t-
Butylperoxyisopropyl) -benzene, benzoyl peroxide, 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane and the like, and useful crosslinking aids include, for example, Divinylbenzene, trimethylolpropane triacrylate, ethylene dimethacrylate, diallyl phthalate,
Examples include quinone dioxime, phenylene bismaleimide, polyethylene glycol dimethacrylate, and unsaturated silane compounds. These organic peroxides and crosslinking aids are used in an amount of 0.1% based on 100 parts by weight of the whole compounding material.
The degree of crosslinking can be adjusted arbitrarily in the range of 1 to 5 parts by weight. These organic peroxides and crosslinking assistants can be used in combination of two or more, if necessary. When an unsaturated silane compound is used as a crosslinking aid, crosslinking can be further advanced by contact with moisture in the presence of a silanol condensation catalyst.

The impact absorbing material of the present invention thus obtained is
It can be used by molding it into a desired shape by a known method, for example, injection molding.

The impact absorbing material of the present invention can be used for any application requiring a stress relaxation action. Examples thereof include cushions in many fields, building interior materials, electric / electronic-related products, and various other components.

Suitable cushions include furniture such as sofas and chairs, bedding such as pillows and duvets, vehicle interior materials such as automobile seats, bicycle saddles, etc., but especially movie theaters, theater seats, etc. Suitable for seats that often sit for a long time. In addition, seats for wheelchairs, medical beds, etc.
It is especially suitable for tevices that often take the same posture for a long period of time. Further, it is particularly preferably used for a cushion such as a vehicle seat or an aircraft seat to which vibration is applied. Further, the cushion is also effective as a cushion for animals or for stress relieving of various equipment, in addition to such a cushion for human beings.

[0051]

The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

The physical properties of these examples were evaluated by the following methods. (1) Hardness of material The test method was based on JIS K6301 A type evaluation method.

(2) Compression set The index of the permanent set resistance, which is based on JIS K6301, was evaluated by the strain residual ratio after 100% × 22 hours and 25% deformation.

(3) MFR Evaluation was carried out at 230 ° C. according to the flow test method for thermoplastics of JIS K7210.

(4) Tan δ tan δ was measured by using a shear dynamic viscoelasticity tester (manufactured by Toyo Seiki Co., Ltd.), temperature 25 ° C., strain 10%, frequency 5
It was performed at Hz.

The solubility parameter is measured by a conventional method, and the number average molecular weight is measured by gel permeation chromatography [GPC; Tosoh GMH-XL (2
Main series)] and using the differential refractive index (RI),
It was carried out in terms of polystyrene using monodisperse polystyrene as a standard. (Example 1) (1) Preparation of impact absorbing material A thermoplastic material for impact absorbing material was prepared using the following raw materials.

Polymer organic material 100 parts by weight (styrene-ethylene / butylene-styrene block copolymer: molecular weight 200,000, SP value 8.5) Softening agent: paraffin oil 58 parts by weight (molecular weight 1,500, SP value 7.8 ) Softener: Paraffin oil 170 parts by weight (molecular weight 750, SP value 7.8) Polyphenylene ether resin 10 parts by weight [Poly (2,6-dimethyl-1,4-phenylene ether)] Polypropylene resin 13.1 parts by weight (iso Tactic polypropylene M-1300, manufactured by Asahi Polypro Co., Ltd.) Higher fatty acid amide 3.0 parts by weight (Armoslip E, manufactured by Lion Co., Ltd.) The respective raw materials were well mixed with a Henschel mixer, and the mixture was a twin screw extruder with a diameter of 50 mm. Melt-kneaded at 240 ° C. to obtain thermoplastic material pellets.

The hardness of this thermoplastic material is 0 ° according to JIS-A, the compression set is 45%, the MFR is 300 g / min,
The tan δ was 0.15. (2) Preparation and evaluation of cushion 270 mm × the obtained thermoplastic material by hot press molding
270 mm x 15 mm thick shape, 270 m
It was sandwiched between polyurethane foams having a thickness of m × 270 mm × 30 mm and put in a commercially available outer cushion to form a cushion. Place the resulting cushion on a wooden chair,
Sitting on it, the shock absorption of the cushion was evaluated. As the shock absorbing property, the fit of the body when sitting, the stability of holding the body, the overall feeling of sitting and the pain of the body after sitting for 2 hours and the feeling of fatigue were evaluated, and all were very good. Or it was good. (Example 2) (1) Preparation of impact absorbing material A thermoplastic material for impact absorbing material was prepared in the same manner as in Example 1 using the following raw materials.

Polymer organic material 100 parts by weight (styrene-ethylene / butylene-styrene block copolymer: molecular weight 200,000, SP value 8.5) Softener: paraffin oil 58 parts by weight (molecular weight 1,500, SP value 7.8 ) Softener: Paraffin oil 73 parts by weight (molecular weight 750, SP value 7.8) Polyphenylene ether resin 10 parts by weight [Poly (2,6-dimethyl-1,4-phenylene ether)] Polypropylene resin 13.1 parts by weight (iso Tactic polypropylene M-1300, manufactured by Asahi Polypro) The hardness of this thermoplastic material was 10 ° in JIS-A, the compression set was 30%, the MFR was 119 g / min, and the tan δ was 0.10. (2) Preparation and Evaluation of Cushion Using the obtained thermoplastic material, a cushion was prepared in the same manner as in Example 1 and the shock absorption was evaluated.
Similar to Example 1, it showed excellent impact absorption. Comparative Example 1 (1) Preparation of Impact Absorber A thermoplastic material for impact absorber was prepared in the same manner as in Example 1 using the following raw materials.

Polymer organic material 100 parts by weight (styrene-ethylene / butylene-styrene block copolymer: molecular weight 30,000, SP value 8.5) Softener: paraffin oil 58 parts by weight (molecular weight 1,500, SP value 7.8 ) Softener: Paraffin oil 73 parts by weight (molecular weight 750, SP value 7.8) Polyphenylene ether resin 15 parts by weight [Poly (2,6-dimethyl-1,4-phenylene ether)] Polypropylene resin 12 parts by weight (isotactic) Polypropylene M-1300, manufactured by Asahi Polypro) The hardness of this thermoplastic material was 5 ° in JIS-A, the compression set was 90%, the MFR was 300 g / min, and the tan δ was 0.10. (2) Preparation and Evaluation of Cushion Using the obtained thermoplastic material, a cushion was prepared in the same manner as in Example 1 and the shock absorption was evaluated.
Each element of shock absorption was normal or bad. Comparative Example 2 (1) Preparation of Impact Absorber A thermoplastic material for impact absorber was prepared in the same manner as in Example 1 using the following raw materials.

Polymer organic material 100 parts by weight (styrene-ethylene / butylene-styrene block copolymer: molecular weight 200,000, SP value 8.5) Softener: paraffin oil 58 parts by weight (molecular weight 1,500, SP value 7.8 ) Softener: Paraffin oil 73 parts by weight (molecular weight 400, SP value 7.8) Polyphenylene ether resin 15 parts by weight [Poly (2,6-dimethyl-1,4-phenylene ether)] Polypropylene resin 12 parts by weight (isotactic) Polypropylene M-1300, manufactured by Asahi Polypro) The hardness of this thermoplastic material was 8 ° according to JIS-A, the compression set was 100%, the MFR was 200 g / min, and the tan δ was 0.10. (2) Preparation and Evaluation of Cushion Using the obtained thermoplastic material, a cushion was prepared in the same manner as in Example 1 and the shock absorption was evaluated.
Each element of shock absorption was normal or bad.

As is clear from the above examples, the shock absorbing material of the present invention has low hardness, low compression set at high temperature (excellent in settling resistance), and suppresses bleeding of low molecular weight materials. Therefore, it can be seen that excellent shock absorption is exhibited.

On the other hand, Comparative Example 1 obtained by using a high molecular weight organic material of hydrogenated block copolymer having a low molecular weight and Comparative Example 2 obtained by using a low molecular weight paraffinic oil as a softening agent to be added It can be seen that although the hardness is low, the compression set is high and the shock absorption is deteriorated.

[0064]

As described above, the impact absorbing material of the present invention has a low hardness, a low compression set at high temperature, and uses a material capable of suppressing bleeding of a low molecular weight material. It has an excellent effect of improving absorbency.

Claims (6)

[Claims] 1. A shock absorber made of a thermoplastic material containing a high molecular weight organic material and a softening agent, the hardness of which is JIS K.
6301 standard A scale, 0 ° to 25 °, 100
Compression set at 5 ° C is 5 according to JIS K6301 standard
0% or less and MFR at 230 ° C is JI
A shock absorber characterized by having a SK7210 standard of 10 g / 10 min or more. 2. The thermoplastic material is a high molecular weight organic material 1.
100 parts by weight and 50 to 500 parts by weight of a softening agent are included, and the difference in solubility parameter between each of the high molecular weight organic material and the softening agent is 3.0 or less. Shock absorber. 3. The shock absorbing material according to claim 1, wherein the thermoplastic material contains 10 to 250 parts by weight of polyphenylene ether. 4. The polymer organic material comprises at least one polymer block containing a vinyl aromatic compound as a main component,
A hydrogenated block copolymer obtained by hydrogenating a block copolymer composed of at least one polymer block mainly composed of a conjugated diene compound, having an average molecular weight of 15
The shock absorbing material according to any one of claims 1 to 3, wherein the shock absorbing material has a viscosity of 10,000 to 400,000. 5. The softening agent is one or more selected from naphthenic oils, paraffinic oils and polyisobutylene oils, and has an average molecular weight of 45.
It is 0-5,000, It is characterized by the above-mentioned.
The shock absorber described. 6. The tan δ of the thermoplastic material is 0.05.
6. The shock absorbing material according to claim 1, wherein the shock absorbing material is 1.0 to 1.0.