JPS6041923B2 - Shoe sole - Google Patents

Description

Detailed Description of the Invention The present invention provides a thermoplastic block copolymer comprising a block copolymer of a conjugated diene compound and an aromatic vinyl compound;
It is made of an elastic material whose main component is a graft copolymer obtained by graft copolymerizing an aromatic vinyl compound and an acrylic monomer to a diene rubber-like polymer, and has heat resistance, oil resistance, and abrasion resistance. It concerns excellent soles.

Conventionally, thermoplastic block elastic bodies (hereinafter referred to as block elastic bodies) made of block copolymers of conjugated diene compounds and aromatic vinyl compounds have shown good rubber elasticity at room temperature and melt at high temperatures. Because it is fluid, it can be molded in the same way as general thermoplastic resins, and is used for shoe soles and industrial rubber products.

In addition to block elastic materials, soft P
There are VC, SBR vulcanized rubber, polyurethane, etc., but those using block elastic bodies are inferior to soft PVC in oil resistance and abrasion resistance, and SBR vulcanized rubber has poor oil resistance and abrasion resistance. It has the disadvantage of poor abrasion resistance and heat resistance. For this reason, for example, when using indoor shoes for school children on waxed floors, the soles will deteriorate and wear faster, and if heat resistance is insufficient and sudden frictional heat is applied. , there is an adverse effect of the flow-a-marking phenomenon, which is thought to be caused by the melting of some polymers. In order to eliminate such drawbacks, the following proposals have been made.

(1) Crosslinking the block elastic body using peroxide.

(2) Mixing thermoplastic resin such as olefin. (3)
Mix oil-resistant rubber (NBR chlorinated polyethylene, etc.). However, none of these methods makes it possible to obtain a material for shoe soles that has physical properties such as heat resistance, oil resistance, and abrasion resistance in a well-balanced manner for practical purposes.

The present invention essentially improves the above-mentioned drawbacks of block elastic bodies and provides a shoe sole with particularly excellent oil resistance.

That is, the present invention provides (4) a thermoplastic block elastomer made of a block copolymer of a conjugated diene compound and an aromatic vinyl compound,
2 parts, (B) a graft copolymer obtained by graft copolymerizing an aromatic vinyl compound and an acrylic monomer to a diene rubber-like polymer (hereinafter simply referred to as a graft copolymer) from 20 to 8 parts. (C) naphthenic process oil in the total amount of the above block elastic body and graft copolymer 10
A thermoplastic elastomer composition containing 10 to 8 parts by weight per 0 parts by weight and 10 to 6 parts by weight per 10 parts by weight of the total amount of the block elastic body and graft copolymer (D) inorganic filler. The present invention provides a shoe sole characterized by comprising the following: and a shoe sole characterized by comprising the thermoplastic elastomer composition thermally crosslinked with an organic peroxide.

The block elastic body used in the present invention is A=+. (B-A)+-.

-, (A-B)n or (A-B)NX. In the formula, A represents an aromatic vinyl compound block, B represents a conjugated diene block, x represents a polyfunctional compound having n polymer chains bonded together, and n is an integer of 2 to 4. Conjugated dienes in the block copolymer include 1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene,
Isoprene, etc., and aromatic vinyl compounds include styrene,
α-methylstyrene, vinyltoluene, t-butylstyrene, etc. It is sufficient that the block elastic body exhibits rubber elasticity, but it is particularly preferable that the block elastic body contains 25 to 5 weight percent of the aromatic vinyl compound block.

When it is less than 25%, the block chains of the aromatic vinyl compound that serve as pseudo-crosslinking points are small, resulting in a decrease in tensile strength and rigidity.

If the amount exceeds 5%, the rubber elasticity decreases, which is not preferable. The diene-based rubbery polymer constituting the graft copolymer used in the present invention includes homopolymers of conjugated diene monomers such as butadiene, isoprene, dimethylbutadiene, cyclopentanediene, chloroprene, and cyanoprene, or dienones thereof. monomers and monomers copolymerizable with them, such as styrene, acrylonitrile,
Examples include copolymers with monomers such as methyl methacrylate, ethyl acrylate, isobutylene, and 1-butene.

Next, the aromatic vinyl compounds to be graft copolymerized include styrene, α-methylstyrene, vinyltoluene,
Examples of acrylic monomers to be similarly graft copolymerized include acrylonitrile, methacrylonitrile, methyl acrylate, methyl methacrylate, ethyl acrylate, and butyl acrylate. The proportion of the diene rubber-like polymer in the graft copolymer is 30 to 7% by weight.
is preferable, and the total amount of the acrylic monomer and aromatic vinyl compound monomer is preferably 70 to 3%.

Furthermore, the weight percent ratio of the acrylic monomer to the aromatic vinyl compound is preferably 40:60 to 10:90. If the proportion of the diene rubber polymer is less than 3% by weight, the rubber properties will deteriorate, which is undesirable, and if it exceeds 7% by weight, fluidity will decrease and moldability will become poor. Furthermore, if the amount of acrylic monomer exceeds 4% by weight in the weight ratio of the two monomer components, the grafted product will discolor to brownish brown, which is undesirable.
If it is less than that, the improvement in oil resistance will be insufficient. The composition ratio of the block elastic body and the graft copolymer is 80:20 to 20.
:8 to preferably 75:25 to 25:75 parts by weight.

If the block copolymer content is outside this range, the oil resistance, heat resistance, and abrasion resistance of the shoe sole will not be sufficiently improved, and if the graft copolymer content is large, the moldability will be poor and the rubber It has poor elasticity and cannot be used as a shoe sole. The naphthenic process oil used in the present invention may be any of those commonly available on the market, but it is preferably composed of 3 to 1 weight percent aromatic, 20 to 4 weight percent naphthenic, and 32 to 4 weight percent aliphatic. It is 65% by weight.

The amount of the naphthenic process oil is 10 to 8 parts by weight, preferably 20 to 6 parts by weight, per 10 parts by weight of the total amount of the block elastomer and graft copolymer.

If it is less than 2 parts by weight, fluidity will be insufficient, and if it exceeds 8 parts by weight, oil resistance will decrease. Naphthenic process oil can adjust the hardness of the composition, improve fluidity, and reduce costs.
For example, a typical shoe sole is required to have a shore hardness A of 50 to 85 at 20 DEG C., and this hardness requirement can be satisfied by adding the above-mentioned 10 to 8 parts. Examples of inorganic fillers used in the present invention include light or heavy calcium carbonate, magnesium carbonate, barium carbonate, silica, aluminum hydroxide, kaolin clay, and carbon black.

The amount of the inorganic filler is 10 to 6 parts by weight, preferably 10 to 5 parts by weight, based on 10 parts by weight of the total amount of the block elastomer and graft copolymer. If the amount added is less than 1 part by weight, it will not substantially help in improving oil absorption and rigidity, and if it exceeds part by weight, the impact resilience of rubber-like properties will decrease. The sole of the present invention is characterized in that it is made of a thermoplastic elastomer composition containing each of the components (A), (B), (C), and (D) described above.

This composition is easy to mold and has excellent oil resistance, abrasion resistance and heat resistance, making it suitable for shoe soles. By crosslinking this composition with an organic peroxide, performance, particularly oil resistance, can be further improved.

Examples of the organic peroxide include benzoyl peroxide, dikymyl peroxide, ditertiary butyl peroxide, t-butyl peroxybenzoate, t-butyl peroxyacetate, and t-butyl peroxyoctoate. The amount of organic peroxide used is 50 to 2000 ppm, preferably 200 to 2000 ppm, based on the total amount of the block elastic body and graft copolymer.
It is pm. If it is less than 50 ppm, the crosslinking effect will be small and performance will not be improved. If it exceeds 2000 ppm, crosslinking will be excessive, resulting in poor flowability and poor processability.

This peroxide is preferably added during the molding step and crosslinked by heating. The heating temperature is preferably 180 to 250°C.
The above thermoplastic elastomer compositions are (A), (B), (C)
Contains the components (9) and (9) as essential components, and in addition,
Anti-aging agents, ultraviolet absorbers, antistatic agents, as needed.
Flame retardants, fillers, reinforcing agents, blowing agents, colorants, lubricants, fragrances, etc. can be included.

Each component of the thermoplastic elastomer composition was prepared using a Henschel mixer,
Shoe soles can be obtained by mixing with a mixing roll, Panbury mixer, single-screw or twin-screw extruder, etc., and then injection molding into a mold.

Examples and comparative examples are shown below.

The block elastic body (4) and graft copolymer used were manufactured as follows. Parts and percentages are based on weight. Production of block elastic body (4) Dehydrated and purified cyclohexane 50e and styrene monomer 1.5k9 were placed in a 100e autoclave, and 100 mmol of n-butyllithium was added and polymerized at 40°C, followed by the addition of 7 kg of butadiene. Then, polymerization was carried out at 60°C for 1 hour.

Next, 1.5 kg of styrene monomer was added and heated to 40°C.
Polymerization was carried out for 1 hour. After terminating the polymerization by adding 10q of methanol, 4-methyl-2,
50y each of 6-ditertyabutylphenol and trinonylphenylphosphite were added, and a polymer [block elastic body (4)] was precipitated by a steam stripping method.

The melt flow index of the obtained block elastic body (
200°C x 5k9 load) was 0.01. Production of graft copolymer (B) Polybutadiene latex (solid content 3) was placed in an autoclave.
0%, volume average particle diameter 0.45μ), 186 parts of pure water, 3 parts of sodium dodecylbenzenesulfonate, 0.0 part of ferrous sulfate, 0.004 part of tetrasodium ethylenediaminetetraacetate, Sodium aldehyde sulfoxylate 0.1? , acrylonitrile 4.8 parts, styrene 112 parts, t-dodecylmercaptan 0.0
96 parts and 0.03 part of benzoyl peroxide were added, and the mixture was stirred under a nitrogen atmosphere.

The contents were heated to 50°C and held for 2 hours. Contains 191 parts of acrylonitrile, 44.8 parts of styrene, 0.384 parts of t-dodecyl mercaptan, and 0 benzoyl peroxide.
．． 1? A monomer mixture consisting of the following was added continuously over 8 hours. After the addition was completed, the mixture was further stirred at 70° C. for 2 hours to complete polymerization, thereby obtaining a latex of the graft material.
A powdery polymer [graft copolymer (B)] was obtained by salting out a calcium chloride aqueous solution.
Example Table 1 shows the composition of the elastic material composition for the sole used for performance evaluation.

However, sample No. 5 and NO. 6 is a comparative example. note(
1) Styrene resin: Denkastyrol manufactured by Denki Kagaku Kogyo Co., Ltd. -2 (Product name) (2) Naphthenic process oil NS-100 (Product name) manufactured by Idemitsu Kosan Co., Ltd. (3) Heavy calcium carbonate Whiten SB manufactured by Shiraishi Calcium
(Product name) After mixing the compositions listed in Table 1 in a Henschel mixer, extrusion temperature was 407n/T at 200°C.
rl, pelletized using an extruder.

The melt flow index of the pellets was measured. The obtained pellets were molded using a Toshiba 1S-12 injection molding machine.
A 19d sole for school children was molded under conditions of a molding temperature of 200°C, a mold temperature of 40°C, and a cooling time of 1 minute. The central part of the heel of the sole was cut out and subjected to an oil resistance test by immersion in JIS-3 oil, and the abrasion resistance and hardness were measured using a taper abrasion tester.

Furthermore, the upper part was connected and assembled into a shoe, and the resulting shoe was subjected to a practical wear test, and the service life until the heel wore out by 57 nm/m was measured.

In addition, the shoes were run under the wax coating using practical shoes, and then stopped to observe the degree of occurrence of the floor marking phenomenon. The above measurement results are shown in Table 2.

Measurement method: Melt flow index ASTM-D-132 (200°C x 5k9 load) Shore hardness A: JI
S-K-6301 oil resistance: JIS-K-6301JIS
-Measuring the weight increase rate after immersion in No. 3 oil at 20℃ for 1 (1) hour Akron-Abrasion: Based on BS standard Part A9C (the angle of inclination between the test piece and the abrasive disk is 15 degrees) Table 2. According to the results, a shoe sole composition (sample No. 5
,llll! 0.6), the example has the same hardness but significantly improved oil resistance and abrasion resistance, and even in the practicality test of practical shoes, the service life was longer and the flow resistance was significantly improved. The marking phenomenon has also been resolved.

Claims (1)

[Scope of Claims] 1(A) A thermoplastic block elastomer made of a block copolymer of a conjugated diene compound and an aromatic vinyl compound.
~20 parts by weight, (B) 20 to 80 parts by weight of a graft copolymer obtained by graft copolymerizing an aromatic vinyl compound and an acrylic monomer to a diene rubber-like polymer, (C) a naphthenic process 10 to 80 parts by weight of oil per 100 parts by weight of the total amount of the block elastic body and graft copolymer, and 10 to 80 parts by weight of (D) inorganic filler per 100 parts of total amount of the block elastic body and graft copolymer. A shoe sole comprising a thermoplastic elastomer composition containing ~60 parts by weight. 2(A) A thermoplastic block elastic body made of a block copolymer of a conjugated diene compound and an aromatic vinyl compound is
~20 parts by weight, (B) 20 to 80 parts by weight of a graft copolymer obtained by graft copolymerizing an aromatic vinyl compound and an acrylic monomer to a diene rubber-like polymer, (C) a naphthenic process 10 to 80 parts by weight of oil per 100 parts by weight of the total amount of the block elastic body and graft copolymer, and 10 to 80 parts by weight of (D) inorganic filler to 100 parts by weight of the total amount of the block elastic body and graft copolymer. A shoe sole comprising a thermoplastic elastomer composition containing 60 parts by weight that is thermally crosslinked with an organic peroxide.