JPH0343446A - Rubber composition - Google Patents

Abstract

PURPOSE:To obtain a rubber composition, excellent in wet gripping properties, abrasion and oil resistance, etc., and suitable as sports shoes, balls for sports, etc., by blending an epoxidized diene-based rubber with a specific thermoplastic elastomer in a specified amount. CONSTITUTION:A rubber composition obtained by blending (A) 10-70wt.%, preferably 20-50wt.% epoxidized diene-based rubber having -65 to +20 deg.C Tg, 10-90mol% epoxidation degree and <=120 ML1+4 Mooney viscosity (100 deg.C) with (B) 30-90wt.%, preferably 50-80wt.% thermoplastic elastomer selected from block copolymers, having >=70wt.% vinyl bond content, >=5wt.% crystallinity and >=0.5 dl/g [eta] (in toluene at 30 deg.C) and composed of polymer blocks consisting essentially of 1,2-polybutadiene and >=1 aromatic vinyl compounds and polymer blocks consisting essentially of >=1 conjugated dienes, hydrogenated substance of the above-mentioned block copolymers and ethylene-vinyl acetate copolymer.

Description

Detailed Description of the Invention a. Industrial Application Field The present invention has excellent wet grip properties and abrasion resistance, and is suitable for use in sports shoes, safety shoes, various types of athletic shoes, men's and women's shoes, sports balls, Used in gloves, golf grips, snow tire treads, and because of its excellent oil resistance and adhesive properties, it is used in automobile interior parts, conveyors, tires, sealants, etc. Because of its high energy loss, it is used in shock absorbers, vibration damping materials, sound absorbing materials, and sound insulation. Due to its high fluidity and green strength, it is suitable for materials, soundproofing materials, rubber processing modifiers, non-crosslinked molded products (footwear, daily necessities, foot rubber, industrial products, building parts, automobile parts, electrical parts, OA parts, etc.), The present invention relates to a rubber composition suitable for use in foam molded products.

b. Prior Art Diene rubbers, especially natural rubber, have excellent mechanical properties (tensile strength, tear strength, etc.) in the rubber field, and are therefore used in many applications such as tires, industrial goods, and footwear. However, it also has poor oil resistance and fluidity, and improvements are desired.

On the other hand, NBR (Trill rubber) is a rubber that has excellent oil resistance and has unique application areas such as industrial products, automobile parts, and footwear. However, it has problems with water resistance, ozone resistance, fluidity, and green strength, and improvements are desired.

In addition, 11R (butyl rubber) has high weather resistance, high energy loss, and high gas barrier properties, so it is useful for automobile tubes and vibration damping materials, but its low crosslinking activity and low fluidity limit its uses.

SBR (styrene-butadiene rubber), which is a general-purpose rubber, has problems in fluidity and oil resistance, and is not satisfactory.

Furthermore, thermoplastic elastomers, which are located between rubber and plastics, are also used for applications characterized by moldability and fluidity, but they have problems with oil resistance and wet grip properties.

As described above, each of the above-mentioned rubbers and elastomers are used for specific purposes by taking advantage of their characteristics, but in terms of their positioning as materials that can be used for multiple purposes, which is required today, they have a low level of performance that cannot be compared with the composition of the present invention. It's on the level.

Problems to be solved by the invention As a result of intensive studies on usable compositions, we discovered that the above object can be achieved by blending an epoxidized diene rubber with a specific thermoplastic elastomer, and based on this knowledge, we have arrived at the present invention.

A means for solving the d9 problem, that is, the present invention, is as follows: (A) Tg (glass transition point) is -65 to 20°C, degree of poxidation is 10 to 90 mol%, and Mooney viscosity is 120 ML.
(100°C) or less Epo 1+4 Oxylated diene rubber 10-70% by weight (B) Vinyl bond content is 70% or more, crystallinity is 5%
Above, [η] (toluene, 30°C) is 0.5dj2/
g or more of 1,2-polybutadiene, at least one aromatic vinyl-based polymer block and at least one
30 to 90% by weight of at least one thermoplastic elastomer selected from block copolymers consisting of polymer blocks mainly composed of conjugated dienes, hydrogenated products thereof, and ethylene-vinyl acetate copolymers. The present invention provides a rubber composition having the following characteristics.

The epoxidized diene rubber (hereinafter abbreviated as ENR) used in the present invention as component (A) can be produced, for example, by reacting the diene rubber, preferably its latex, with peracetic acid.

As diene rubber, natural rubber (NR), IRSBR
, SBR, NBR, etc. Among these, preferred is NRlIR, and more preferred is NR.

The Tg (glass transition point) of ENR is -65 to 20°C, preferably -60-0°C, more preferably 50 to -10'
It is C. If the temperature is less than -65°C, oil resistance, wet grip properties, and adhesion will be impaired, and if it exceeds 20°C, cold resistance will be impaired. The degree of epoxidation is 10 to 90 mol%, preferably 15 to 70 mol% of the unsaturated bonds in the diene rubber.
It is mol%, more preferably 25 to 60 mol%. 1
If it is less than 0 mol%, oil resistance, wet grip properties, and adhesion will be impaired, and if it exceeds 90 mol%, cold resistance will be impaired. Note that it is preferable that the epoxy groups are randomly distributed.

In the composition of the present invention, the blending amount of component (A) is 1
The content is 0 to 70% by weight, preferably 15 to 60% by weight, and more preferably 20 to 50% by weight. If it is less than 10% by weight, oil resistance and adhesion will be impaired, and if it exceeds 70% by weight, uniform dispersibility and fluidity will be impaired.

The component (B) used in the present invention will be explained.

1.2-Polybutadiene (hereinafter abbreviated as RB) is 1,
The number of 2-bonds is 70% or more, preferably 85% or more.

When the 1,2-bond is less than 70%, wet grip properties are impaired. Crystallinity is 5% or more, preferably 10~
It is 40%. When the degree of crystallinity is less than 5%, fluidity is impaired, and when it is more than 40%, compatibility with ENR is impaired.

[η] is 0.5 coagulation/g or more. 0. If it is less than 5c[/g, oil resistance will be impaired.

Block copolymers and hydrogenated block copolymers are block copolymers consisting of at least one aromatic vinyl-based polymer block and at least one conjugated diene-based polymer block. It is.

The composition ratio of aromatic vinyl/conjugated diene constituting the block copolymer is preferably 5 to 9515 to 95% by weight,
More preferably, it is 15-60/40-85% by weight, and the structure may be linear, branched, or radial.

A polymer block mainly composed of aromatic vinyl is a homopolymer of aromatic vinyl, or a conjugate of aromatic vinyl with a conjugated diene, preferably containing 60% by weight or more, more preferably 80% by weight or more. It is a polymer block.

A polymer block mainly composed of a conjugated diene is a homopolymer of a conjugated diene, or a conjugated diene preferably composed of 60%
It is a copolymer block of conjugated diene and aromatic vinyl in an amount of at least 80% by weight, more preferably at least 80% by weight.

The preferred number average molecular weight of the block copolymer is 5°000
~1,000,000, more preferably 30,000
~300,000.

The aromatic vinyl is preferably styrene, and the conjugated diene is preferably butadiene.

Examples of block copolymers include the following.

Here, A: Vinyl aromatic compound polymer B: Conjugated diene polymer A/B: Random copolymer of vinyl aromatic compound/conjugated diene: A copolymer of a conjugated diene and a vinyl aromatic compound,
and a tapered block fl in which the vinyl aromatic compound gradually increases] A-B (2+ A-B-A (3) A-B-C (4) A-B1-82 (The vinyl bond of B+ is preferably 20% or more, The vinyl bond of B2 is preferably less than 20%) F5] A -A
/ B (61A -A / B -C (7) A -A / B -A f8) B2-B+ -B2 (B+ vinyl bond is preferably 20% or more, B2 vinyl bond is preferably less than 20%) (91C-B (10) C-B -C (11) C-A / B-C (12) C-A-B The hydrogenated product of the present invention is obtained by hydrogenating the above-mentioned block copolymer. It can be obtained by

In order to obtain the effect of weather resistance and heat resistance by hydrogenation, the hydrogenation rate of the block copolymer is preferably 70% or more, more preferably 95% by weight or more of olefinic unsaturated bonds. be.

The ethylene-vinyl acetate copolymer preferably has a vinyl acetate bond content of 5 to 45%, more preferably 10%.
~30%, melt flow index (190℃, 21
60g) is preferably 0゜2~50g/10m1n
, more preferably 0.5 to 20 g/10 m1n.

Component (B) is preferably 1,2-polybutadiene, a block copolymer, or a hydrogenated product thereof, and more preferably a hydrogenated product of 1,2-polybutadiene or a block copolymer. A rubber composition, which is the object of the invention, is obtained.

The blending amount of component (B) is 30 to 90% by weight, preferably 40 to 85% by weight, and more preferably 50 to 80% by weight. If it is less than 30% by weight, uniform dispersibility and fluidity will be impaired, and if it exceeds 90% by weight, oil resistance and adhesiveness will be impaired.

Other rubbery polymers, resins, and various additives may be added to the composition of the present invention as long as the effects of the present invention are not impaired.

Rubbery polymers include butadiene rubber, butyl rubber,
Emulsion or solution polymerized high styrene (ST50% or higher) type styrene-butadiene copolymer rubber, 3.4-bonded isoprene rubber, fluororubber, chloroprene rubber, acrylic comb (ACMSANM), NV (acrylonitrile-
butadiene rubber and vinyl chloride blend) rubber, halogenated butyl rubber, natural rubber, isoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, ethylene-propylene rubber, solution polymerized styrene-butadiene rubber, and the like.

Examples of the resin include ethylene-ethyl acrylate copolymer, polyester, polyurethane, and nylon.

Examples of softeners include process oils, lubricating oils, paraffin, liquid paraffin, petroleum asphalt, petroleum softeners such as vaseline, coal tar softeners such as coal tar and coal tar pitch, linseed oil, and rapeseed oil. , fatty oil-based softeners such as coconut oil, tall oil, sub-oil, waxes such as beeswax, carnauba wax, and lanolin,
Examples include fatty acids and fatty acid salts such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, calcium stearate, and zinc lanophosphate, and synthetic polymeric substances such as petroleum resins.

Examples of the adhesive include rosin resins, terpene resins, terpene modified resins, aliphatic/aromatic petroleum resins, coumaron indene resins, and the like.

Inorganic fillers include light carbonate, heavy carbonate, various surface-treated calcium carbonates, as well as talc, magnesium hydroxide, mica, clay, barium sulfate, natural silicic acid, synthetic silicic acid, titanium oxide, Glass fibers, carbon fibers, cotton flock and various carbon blacks can be used.

Depending on the purpose of use, the composition of the present invention may contain chemicals used for rubbers and resins, such as crosslinking agents, activators, plasticizers, dispersants, coupling agents, heat stabilizers, ultraviolet absorbers, and foaming agents. I can do it. Among these, in the case of sulfur crosslinking formulation, the crosslinking agent is powdered sulfur, precipitated sulfur, surface treated sulfur, etc., and the accelerator is TMTDlTMTM, OBS, C
BS, MBTSSMBT, etc. can be used.

In the case of organic peroxide crosslinking, dicumyl peroxide, di-t-butylperoxy-3,3゜5-trimethylcyclohexane, α,α-di-t-butylperoxy-p-diisopropylbenzene, n- Butyl-4,4-
Bis-t-butylperoxyvalerate, t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di(t
butylperoxy)hexane, etc. can be used.

Furthermore, in the case of peroxide crosslinking, various polyfunctional monomers may be added at the same time.

As blowing agents, inorganic blowing agents such as ammonium carbonate, sodium bicarbonate, and non-sodium nitrate, dinitrosopentamethylene lentyramine, N, N'dimethyl-N, N'
- dinitrone terephthalamide, benzenesulfonyl hydrazide, p-h luenesulfonyl hydrazide, P,
P'-oxybis(benzenesulfonylhydrazide)
, 3,3'-disulfone hydrazide diphenyl sulfone, azobisisobutyronitrile, azodicarboxamide and the like.

Further, a urea-based, organic acid-based, or metal salt-based foaming aid can be used together with the foaming agent. The foaming aid is used together with a foaming agent having a high decomposition temperature, such as dinitropentamethylenetetramine or azodicarbonamide, and is added for the purpose of appropriately lowering the foaming temperature.

There is no particular restriction on the method of mixing the above (A), (B) and other compounding materials, and the method may be a Banbury type mixer, pressure kneader,
This is possible using the mixing method used for general rubber compounds such as open rolls.

The compound thus obtained is formed into a sheet or pellet using a calender roll, an extruder, etc., and then crosslinked or non-crosslinked by press bottom molding, stretch molding, injection molding, hot air molding, etc. It can be used in various fields in the form of solid, foam, etc.

The composition of the present invention can be applied to sports shoes, safety shoes, various athletic shoes, men's and women's shoes, sports balls, gloves, protectors, golf grips, snow tires [red, adhesives, automobile interior materials, conveyor tires, sealants] -,
Shock absorber-1 Vibration damping material, sound absorbing material, sound insulating material 1. Vibration isolation materials, joint materials, rubber processing modification materials, electrical parts, building material parts,
It can be widely used for crosslinked molded products such as OA parts, non-crosslinked molded products, and foam applications.

e. Examples Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

In this example, the hardness was measured in accordance with the Type A method of JIS K6301, and the specific gravity was measured by the buoyancy method.

The wet grip property was measured using a wet skid resistance tester manufactured by JSR (Japanese Patent Laid-Open No. 61-117430), and the judgment was as follows: ○: Torque of 250 g-cm or more, Δ: Torque of 200 to 249 g-cm.

×: Torque was 199 g-cm or less.

Abrasion resistance is based on the DIN method, and the judgment is ○: 300nuA
Hereinafter, Δ: 301 to 449 mm, X: 450 mn1 or more.

For oil resistance, AST M No. 3 oil is used.
The volume increase rate (%) after immersion at 25° C. for 4 days was evaluated, and the judgment was as follows: ◯: 40% or less, △: 41 to 60%, ×: 61% or more.

The fluidity was determined as 1 (1) at MFR of 150° C. and 2160 g, and the judgment was as follows: ○: 1 g710 m1n or more, Δ: 0.2 to 0°9 g/10 m1n, x: 0.Ig/10 m1n or less.

Adhesion was evaluated using Primer RB11 (compound molded test piece treatment) manufactured by Naucheve Industries, and adhesive #955, and the adhesive strength with natural leather for puffing was evaluated, and the judgment was ○: 7k.
g/2.5cm or more, △: 5-6, 9kg/2. 5
cm, X: 4.9 kg/2.5 cm or less.

The damping property was evaluated based on the loss coefficient in accordance with the JAS impedance method (attached to a 0.8 mm thick 40×400 m board with a thickness of 2 mm). Judgment: ○: η0.2 or more, △:
η 0 , 19 ~ η 0 , 1 , ×
: η 0 was set to 09 or less.

In addition, ENR-1 used in the examples was 25 mol%
Epoxidized NR (made in Malaysia), ENR-2 is 50 mol% epoxidized NR (made in Malaysia), RB810, R
B820SRB830 has crystallinity of 18%, 24%, 2
8% 1,2-polybutadiene (manufactured by Japan Synthetic Rubber),
BRO2LL, BRol have 94% cis-1,4-bonds,
96% polybutadiene (manufactured by Japan Synthetic Rubber), 40% dicumyl peroxide type (manufactured by Nihon Yushi), foaming agent,
ADCA (AC#3, AK#2) and auxiliary agent (K#5
) was made by Hydration Kasei, and the other chemicals and additives used were those used for general rubber.

[Example 1.2] Example 1.2 is an example of a non-crosslinked product, in which the formulation shown in Table 1 was put into a 3°C pressurized Nigu, and heated at 70 to 120°C for 1 hour.
After kneading for 0 minutes, the mixture was made into a sheet with a thickness of 3 to 5 mm using a roll machine, pelletized using a sheet pelletizer, and extruded into a predetermined shape using a 40 mm extruder at 130 to 150°C to obtain a test piece. The physical property test results are shown in Table-1.

[Example 3.5.6] Example 3.5.6 is an example of a non-crosslinked product, and the molding method was injection molding (temperature 110 to 160°C, medium speed 900 kg /
ct pressure, 10 seconds injection, mold temperature 10°C) Example 1
A test piece was obtained by processing in the same manner as above. The physical property test results are shown in Table-1.

[Example 4] Example 4 is an example of a non-crosslinked product, and a test piece was obtained by processing in the same manner as in Example 3 except that a foam was made by adding a blowing agent. Physical properties of eggplant l-Results are shown in Table-1.

[Examples 7, 8, and 9 Examples 7 to 9 are examples of crosslinked products, and the formulations shown in Table 2 were used for 31! , put into a pressurized Negoo, knead at 70-120°C for 10 minutes, then form into a sheet into a predetermined shape with a roll machine, press (160°C, 10-15 minutes),
A prescribed test piece was obtained.

The physical property test results are shown in Table-2.

[Example 10] Example 10 is an example of a crosslinked product, and the molding method was hot air (14
A test piece was obtained in the same manner as in Example 7 except for crosslinking in the lower oven (0 to 180'C, 20 to 40 minutes). The physical property test results are shown in Table-2.

[Comparative Examples 1 to 4] Comparative Examples 1.2.3.4.7 are examples of non-crosslinked products, and test pieces were prepared in the same manner as in Example 1.3, except that the formulation was outside the scope of this claim. Obtained. Moreover, Comparative Example 4 is an example using NR that is not converted into Evokin. Table of physical property test results
Shown in 1.

Comparative Example 5.6.8 Comparative Example 5.6 is an example of a crosslinked product, and a test piece was obtained in the same manner as in Example 7, except that the composition was outside the scope of this claim. The physical property test results are shown in Table-2.

From Table-1 and Table-2, Examples 1 to 1 which are compositions of the present invention
0 indicates excellent performance in wet grip properties, abrasion resistance, oil resistance, fluidity, adhesion, and vibration damping properties compared to Comparative Examples 1 to 5, which are compositions outside the scope of the present invention. I understand that.

The following margin f1 Effect of the invention The composition of the invention has excellent wet grip properties and a resistance to 19
Because of its corrosion resistance, it is used in sports shoes, safety shoes, men's and women's shoes, athletic equipment, and tire treads, and because of its excellent oil resistance and adhesive properties, it is used in automobile interior materials, conveyors, belts, tires, sealants, etc., resulting in large energy losses. Therefore, shock absorbers - damping materials, sound absorbing materials, sound insulation materials, and soundproofing materials.
Due to its high fluidity, it can be suitably used for rubber processing modifiers, non-crosslinked molded products, foamed molded products, etc.
It can be used in a wide range of applications and has extremely high industrial value.

Claims (1)

[Claims] (A) Tg (glass transition point) is -65 to 20°C, epoxidation degree is 10 to 90 mol%, and Mooney viscosity is 120ML_
1_+_4 (100℃) or less epoxidized diene rubber 10 to 70% by weight (B) Vinyl bond content is 70% or more and crystallinity is 5%
Above, 1,2-polybutadiene with [η] (toluene, 30°C) of 0.5 dl/g or more, a polymer block mainly composed of at least one aromatic vinyl, and at least one conjugated diene. 30 to 90% by weight of at least one thermoplastic elastomer selected from a block copolymer consisting of a polymer block, a hydrogenated product of the block copolymer, and an ethylene-vinyl acetate copolymer. rubber composition.