JP3503339B2 - Thermoplastic elastomer composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic elastomer composition, which has flexibility, rubber elasticity, heat resistance, weather resistance,
The present invention relates to a thermoplastic elastomer composition having excellent mechanical strength and moldability and having little bleeding of a softening agent, such as food use, daily sundries use, toys and exercise equipment use, stationery use such as desk mats, automobile interior and exterior. Applications, civil engineering sheets, waterproof sheets, civil engineering / construction applications, AV / home appliance applications, OA / office equipment applications, clothing / footwear applications, textile applications, medical device applications such as various catheters, disposable diapers / sanitary products, etc. Hygiene products, chemical and mining materials,
It can be used for packaging and transportation materials, agricultural / livestock / fishery materials, etc.

[0002]

2. Description of the Related Art In recent years, a thermoplastic elastomer (hereinafter abbreviated as TPE), which is a rubber-like soft material and does not require a vulcanization step and has a moldability similar to that of a thermoplastic resin, has been used for automobile parts, It is used in the fields of home electric appliances, medical equipment, food equipment parts, electric wires and sundries. Currently, such TPEs include polyolefin-based, polyurethane-based,
Polymers of various types such as polyester type and polystyrene type have been developed and are commercially available. However, these TPEs have not reached the level of the vulcanized rubber in terms of quality in the use of the vulcanized rubber, which is one of the wide fields of application as a rubber, and therefore they are used in the vulcanized rubber field. Are extremely limited.

For example, although polyolefin-based TPE is relatively inexpensive and excellent in heat resistance and weather resistance, a soft one cannot be obtained, and even the most flexible one is JIS-A hardness (JI).
S-K6301) is about 70, which is still too hard compared to JIS-A hardness 60 of general vulcanized rubber. Also, JIS
-The tensile strength in the low hardness region around A hardness 70 is 25.
~ 45kg / cm ² , about 100kg / cm of vulcanized rubber
Considerably lower than ² . Polyester-based TPE and polyurethane-based TPE also have the JIS-A hardness of 80 to 90, which is the most flexible of the commercially available products, and are extremely hard as compared with vulcanized rubber, and are not suitable for the application field of vulcanized rubber.

On the other hand, polystyrene TPEs such as styrene-butadiene-styrene block polymer (SBS) and styrene-isoprene-styrene block polymer (SIS) are more flexible than the above TPEs and have good rubber elasticity. However, since it has a double bond in the polybutadiene block or polyisoprene block in the polymer, there is a problem in heat aging resistance (heat stability) and weather resistance.

By hydrogenating the intramolecular double bond of the block copolymer of styrene and a conjugated diene, an elastomer having improved thermal stability can be obtained. The thermoplastic elastomer containing this elastomer as a rubber component is superior in flexibility, rubber elasticity, and strength as compared with the olefin-based TPE, but has a tensile strength of 70 to 90 kg / cm ² near JIS-A hardness of 50, Inferior to vulcanized rubber.

[0006]

The object of the present invention is to provide thermoplastic elastomers with excellent flexibility, rubber elasticity, heat resistance,
It is an object of the present invention to provide a thermoplastic elastomer composition which does not impair physical properties such as weather resistance and molding processability, has little bleeding of a softening agent, and has mechanical strength close to that of a vulcanized rubber.

[0007]

As a result of various studies to solve the above problems, the present inventor has found that hydrogenated derivatives of a block copolymer composed of a monovinyl-substituted aromatic hydrocarbon block / conjugated diene block. , By blending a hydrocarbon-based rubber softening agent and an olefin resin with a special hydrogenated diene-based block copolymer as an essential component,
The present invention has been completed by discovering that flexibility, rubber elasticity, heat resistance, weather resistance, molding processability are excellent and that mechanical strength is dramatically improved. That is,
The thermoplastic elastomer composition of the present invention,

[0008]

[Chemical 3]

[0009] [Wherein A is a monovinyl-substituted aromatic hydrocarbon polymer block and B is a It is an elastomeric polymer block of a role diene, and n is an integer of 1 to 5] The hydrogenated derivative of the block copolymer represented by the formula (1) has a weight average molecular weight of 100,000-4. Copolymerization in which the content of the polymer block (A) in the copolymer is 20 to 40% by weight Body: 30-60% by weight   (B) Hydrocarbon-based rubber softening agent: 40 to 70% by weight To 100 parts by weight of the total of the components (a) and (b)   (C) Olefin-based polymer: 3 to 100 parts by weight

[0010]

[Chemical 4]

[0011] (wherein, C is 1,2 proportion of vinyl bond of 20% or less of polybutadiene Nbu lock, D polybut diene block ratio of the vinyl bond is 25 to 95 percent, n represents 1 or more, m is 2 The above is shown.) To provide a thermoplastic elastomer composition.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The monomer monovinyl-substituted aromatic hydrocarbon constituting the polymer block (A) as the component (a) is preferably styrene, and α-methylstyrene and the like can also be used. The conjugated diene monomer in the polymer block (B) is preferably butadiene or isoprene, or may be a mixture of both. When butadiene is used as the single conjugated diene monomer to form the polymer block (B), the block copolymer retains elastomeric properties after hydrogenation and saturation of the double bonds. For the purpose, it is preferable to adopt a polymerization condition in which the 1,2-microstructure in the microstructure of polybutadiene is 20 to 50%, and the one having the 1,2-microstructure of 35 to 45% is particularly suitable.

The proportion of the polymer block (A) in the copolymer is 20 to 40% by weight, preferably 25 to 35.
% By weight. When the polymer block (A) is less than 20% by weight, the resulting thermoplastic elastomer is inferior in mechanical strength, rubber elasticity and heat resistance. Further, when the polymer block (A) exceeds 40% by weight, the flexibility and rubber elasticity are poor and, at the same time, the bleeding of the softening agent is deteriorated.

The weight average molecular weight of the hydrogenated block copolymer as the component (a) is in the range of 100,000 to 400,000, preferably 150,000 to 350,000, and more preferably 200,000 to 300,000. If the weight average molecular weight is less than 100,000, the rubber elasticity and heat resistance of the resulting thermoplastic elastomer will be poor.
If it exceeds 0,000, the viscosity will be high and the moldability will be poor. Further, the molecular structure of the hydrogenated block copolymer may be linear, branched, radial or any combination thereof.

Here, the "weight average molecular weight" is a polystyrene equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions. (Conditions) Column: Polystyrene mix gel column Solvent: o-dichlorobenzene Temperature: 140 ° C Flow rate: 1 ml / min Injection volume: 200 μl Concentration: 2 mg / ml (2,6-di-
Add 0.2% by weight of t-butyl-p-phenol. Concentration detection is measured with an infrared spectrophotometer at a wavelength of 3.42 μm. ) As a method for producing these block copolymers, any method can be used as long as the above-mentioned structure can be obtained. For example, it can be obtained by block polymerization in an inert solvent using a lithium catalyst or the like according to the method described in JP-B-40-23798.

The hydrogenation treatment of these block copolymers is carried out, for example, in Japanese Examined Patent Publication Nos. 42-8704 and 43-43.
Hydrogenation is carried out in the presence of a hydrogenation catalyst in an inert solvent by the method described in Japanese Patent No. 6636 or Japanese Patent Laid-Open Nos. 59-133203 and 60-79005. In this hydrogenation, at least 50%, preferably 80% or more of the olefinic double bonds in the polymer block B are hydrogenated, and 25% or less of the aromatic unsaturated bonds in the polymer block A are hydrogenated. It Examples of such hydrogenated block copolymers are commercially available from Shell Chemical Co. [KRATON-G] and from Kuraray Co., Ltd. under the trade name “Septon”.

The rubber softening agent used as component (b) in the present invention has a weight average molecular weight of 300 to 2,000.
Hydrocarbons of 0, preferably 500 to 1,500 are used, and mineral oil type or synthetic resin type is suitable. The mineral oil-based softening agent is a mixture of the aromatic ring, the naphthene ring and the paraffin chain, and the paraffin chain carbon number accounts for 50% or more of the total carbon is called paraffin oil. A naphthenic oil having a naphthene ring carbon number of 30 to 45% is called an naphthenic oil, and has an aromatic carbon number of 35.
% Or more are classified as aromatic oils. Among these, paraffinic oil is preferable as the softening agent for rubber.

The paraffinic oil has a kinematic viscosity at 40 ° C. of 20 to 800 cSt, preferably 50 to 600 cS.
t, the pour point is 0 to -40 ° C, preferably 0 to -30 ° C,
Also, an oil having a flash point (COC) of 200 to 400 ° C., preferably 250 to 350 ° C. is suitably used. As the synthetic resin softening agent, polybutene, low molecular weight polybutadiene, etc. can be used, but a mineral oil softening agent is preferable.

As the olefin polymer used as the component (c) in the present invention, an olefin homopolymer or copolymer can be used, and a differential calorimeter (DSC) is used.
190 with a melting peak temperature of less than 130 ° C
The melt flow rate (JIS-K7210) at 230 ° C is 0.01 to 100 g for those of 130 ° C or higher.
/ 10 minutes, preferably 0.05 to 80 g / 10 minutes, particularly preferably 0.1 to 60 g / 10 minutes. Bending modulus 500 kg / cm ² or more, preferably 1,000~20,000kg / cm ^2, more preferably 3,000~15,000kg / cm ² is desirable.

Specific examples thereof include ethylene-based polymers, propylene-based polymers, polybutene-1 and poly-4-methylpentene-1. The olefin-based polymers are preferably ethylene-based polymers and propylene-based polymers. Is. Examples of the ethylene-based polymer include high-density, medium-density or low-density polyethylene, ethylene / propylene copolymer, ethylene / butene-1 copolymer, ethylene / hexene copolymer, ethylene / heptene copolymer, ethylene.・
Octene copolymer, ethylene-4-methylpentene copolymer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer, ethylene / methacrylic acid copolymer, ethylene / Methacrylic acid ester copolymers and the like can be mentioned, and preferable ones as the ethylene-based polymer are high density, medium density and low density polyethylene.

The propylene-based polymer includes polypropylene, propylene-ethylene copolymer, propylene
Butene-1 copolymer, propylene / ethylene / butene-
1 copolymer, propylene-4-methylenepentene-1 copolymer and the like, and preferred as the propylene-based polymer are polypropylene and propylene-ethylene copolymer.

The hydrogenated diene-based block copolymer used as the component (d) in the present invention is a polybutadiene polymer block (C) having a 1,2-vinyl bond ratio of 20% or less, a vinyl of a conjugated diene portion. Bonding ratio is 25-9
Consisting of 5% conjugated diene polymer block (D),
And the block structure

[0023]

[Chemical 5]

[Wherein n is 1 or more and m is 2 or more], the conjugated diene moiety of the linear block copolymer is 80
It can be obtained by hydrogenation of at least%. The block (C) in the component (d) becomes a crystalline polymer block having a structure similar to that of a normal linear low density polyethylene by hydrogenation. The 1,2-vinyl bond content in the block (C) is 20% or less, preferably 18% or less, more preferably 15% or less. When the content of 1,2-vinyl bond in the block (C) exceeds 20%, the crystal melting point after hydrogenation is remarkably lowered, resulting in poor mechanical strength, which is not preferable.

Next, examples of the conjugated diene used in the block (D) include butadiene and isoprene, with butadiene being preferred. The block (D) becomes a rubber-like ethylene-butene copolymer block by hydrogenation, for example, when the conjugated diene is butadiene. The vinyl bond content of the conjugated diene portion of the block (D) is 25 to 9
5%, preferably 25-75%, more preferably 25
If it is less than 25% or more than 95%, by hydrogenation, for example, when the conjugated diene is butadiene, it shows a crystalline structure derived from a polyethylene chain or a polybutene-1 chain, respectively, and becomes resin-like and has flexibility. Is inferior and is not preferable.

Block (C) /
The weight ratio of (D) is usually 5/95 to 90/10, preferably 10/90 to 85/15. Less than 5% by weight of block (C) [95% by weight of block (D)
In the case of [>], the crystalline polymer block is insufficient and the mechanical strength is poor, which is not preferable. Further, when the block (C) exceeds 90% by weight [the block (D) is less than 10% by weight], the flexibility is insufficient, which is not preferable.

Further, the hydrogenated diene block copolymer used in the present invention has at least 80 double bonds of the conjugated diene moieties of the block (C) and the block (D).
%, Preferably 90% or more, more preferably 95% or more, must be hydrogenated and saturated,
If it is less than 80%, the heat resistance, weather resistance and strength are poor. The weight average molecular weight of the hydrogenated diene-based copolymer is 50,000 to 400,000,
Preferably 100,000 to 300,000, more preferably 150,000 to
It is 250,000. When it is less than 50,000, heat resistance, strength, fluidity and workability are deteriorated, and when it exceeds 400,000, fluidity, workability and flexibility are unfavorably deteriorated. Here, the "weight average molecular weight" is
It is measured by GPC in the same manner as the above-mentioned component (a).

The hydrogenated diene block copolymer used in the present invention may be modified with a functional group, and is selected from at least an acid anhydride group, a carboxyl group, a hydroxyl group, an amino group, an isocyanate group and an epoxy group. Using an unsaturated compound having one functional group, a kneader, a mixer,
It can be modified with an extruder or the like. The hydrogenated diene block copolymer of the present invention is produced by living anion polymerization and further hydrogenation as disclosed in JP-A-3-128957. As the hydrogenated diene-based block copolymer of the component (d) of the present invention, the above-mentioned ones may be used alone or in combination of two or more kinds. Among these,

[0029]

[Chemical 6]

Those based on a linear block copolymer represented by (n is 1 or 2 and m is 2 to 4) are preferable,
It is more preferably C-D-C or (C-D) ₂ , and most preferably C-D-C type. As such a hydrogenated diene-based block copolymer, there is a commercially available product from Nippon Synthetic Rubber Co., Ltd. under the trade name of "Dinalon".

The mixing ratio of the respective components constituting the thermoplastic elastomer of the present invention is 30 to 60% by weight, preferably 35 to 60% by weight of the component (a) with respect to the total amount of the component (a) and the component (b). 55% by weight. When the amount of the component (a) is less than 30% by weight, the rubber elasticity and heat resistance of the obtained thermoplastic elastomer are poor and the bleeding property of the softening agent is deteriorated.
If the amount of the component (a) exceeds 60% by weight, the flexibility and molding processability deteriorate.

The content of the component (c) is 3 to 100 parts by weight, preferably 4 to 75 parts by weight, more preferably 5 parts by weight, based on 100 parts by weight of the total amount of the components (a) and (b).
˜50 parts by weight. When the amount is less than 3 parts by weight, the thermoplastic elastomer obtained is inferior in moldability, and when the amount is more than 100 parts by weight, the flexibility of the thermoplastic elastomer is lost and the bleeding property of the softening agent is deteriorated.

The content of the component (d) is 3 to 50 parts by weight, preferably 4 to 40 parts by weight, and more preferably 5 to 100 parts by weight of the total amount of the components (a) and (b).
30 parts by weight. When the amount is less than 3 parts by weight, the effect of improving the strength is not exhibited, and when the amount is more than 50 parts by weight, the flexibility of the thermoplastic elastomer is lost and the molding processability is deteriorated. The thermoplastic elastomer composition of the present invention,
In addition to the resin essential components, other optional components can be blended according to various purposes within a range that does not significantly impair the effects of the present invention.

As the optional component, for example, an antioxidant,
Heat stabilizer, light stabilizer, ultraviolet absorber, neutralizing agent, lubricant, antifogging agent, antiblocking agent, slip agent, dispersant, colorant, flame retardant, antistatic agent, conductivity imparting agent, crosslinking agent, Crosslinking aids, metal deactivators, molecular weight modifiers, antibacterial agents, various additives such as optical brighteners, thermoplastic resins other than the above essential components, elastomers other than the above essential components, fillers and the like. Any of these can be used alone or in combination.

Here, as the thermoplastic resin other than the essential components, for example, ethylene / vinyl acetate copolymer, ethylene / (meth) acrylic acid copolymer, ethylene. (Meth)
Ethylene / α-olefin copolymers such as acrylic ester copolymers, polyolefin resins such as polyethylene and polybutene-1 resins, polyphenylene ether resins, polyamide resins such as nylon 6 and nylon 66,
Examples thereof include polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyoxymethylene resins such as polyoxymethylene homopolymers and polyoxymethylene copolymers, and polymethylmethacrylate resins.

As the arbitrary elastomer, for example, ethylene / propylene copolymer rubber (EPM), ethylene / propylene / non-conjugated diene copolymer rubber (EPD) is used.
M), ethylene-butene copolymer rubber (EBM), ethylene-based elastomers such as ethylene-propylene-butene copolymer rubber; styrene-butadiene copolymer rubber, styrene-isoprene copolymer rubber and other styrene elastomers; polybutadiene, etc. Can be mentioned. Further, examples of the filler include glass fiber, hollow glass sphere, carbon fiber, talc, calcium carbonate, mica, potassium titanate fiber, silica, titanium dioxide, carbon black and the like.

The thermoplastic elastomer composition of the present invention can be produced by a usual method of mechanically melt-kneading the above components. Examples of the melt-kneader used in the mechanical melt-kneading include a single-screw extruder, a twin-screw extruder, a Brabender plastograph, a Banbury mixer, a kneader blender, and a roll, and preferably 145-300. It can be obtained by kneading each component in the temperature range of ° C. Upon kneading, each component may be kneaded at once, or a multi-stage divided kneading method in which after kneading arbitrary components and then adding the remaining components and kneading can be performed.

The above-mentioned thermoplastic elastomer composition can be prepared by a conventionally known method, injection molding (insert molding method, two-color molding method, sandwich molding method, gas injection molding method, etc.), extrusion molding, inflation molding, T-die film molding,
A practically useful molded product can be processed by molding methods such as laminate molding, blow molding, hollow molding, compression molding, and calendar molding. Molded articles obtained in this manner are automobile parts, industrial parts such as home appliance parts, food packaging materials,
It can be used for medical equipment parts, furniture parts, daily sundries, etc.

[0039]

EXAMPLES The present invention will be specifically described with reference to the following experimental examples. These examples and comparative examples were evaluated by the evaluation methods shown below. However, the measurement sample is
All are in-line screw type injection molding machines (small injection molding machine: IS90B manufactured by Toshiba Machine Co., Ltd.), injection pressure 500 kg / cm ² , injection temperature 200 ° C., mold temperature 40.
Molded under the condition of ℃, 120mm × 80mm × 2mm
It was obtained by punching a thick sheet in the lateral direction.

(1) Flexibility JIS-A hardness was measured according to JIS-K6301. (2) Rubber elasticity and heat resistance In accordance with JIS-K6301, compression set (70 ° C x
(22 hours) [%] was measured. (3) Mechanical strength Punching was performed with a No. 3 dumbbell, and the tensile strength at break [kg / cm ² ] was measured according to JIS-K6301. (4) The softening agent bleed injection-molded sheet was allowed to stand at room temperature for 30 days and then visually evaluated for stickiness on the surface. (5) Molding processability In the injection-molded sheet obtained under the above-mentioned molding conditions, when there was no shot shot and there was no remarkable appearance defect such as a flow mark, the molding processability was made good.

The ingredients used in the examples and comparative examples are as follows. Component (a): Block structure of hydrogenated derivative (a-1 to 9) of monovinyl-substituted aromatic hydrocarbon / conjugated diene block copolymer, monomers constituting polymer blocks (A) and (B), weight The average molecular weight and polymer block (A) content are shown in Table 1.

[0042]

[Table 1]

(B) Component (B-1) Softener for hydrocarbon rubber: Paraffin oil “PW380” manufactured by Idemitsu Kosan Co., Ltd. 40 ° C. Kinematic viscosity: 381.6 cSt Pour point: −15 ° C. Flash point: 300 ° C. Weight Average molecular weight: 746

(C) Component (C-1) Olefin-based resin: High-density polyethylene Mitsubishi Polyethylene-HD "HJ490" Density: 0.958 MFR: 20 g / 10 minutes (190 ° C, 2.16 kg) Elastic modulus: 11, 000 kg / cm ² (C-2) Olefin resin: Polypropylene Mitsubishi Polypro “MA2P” MFR: 16 g / 10 min (230 ° C., 2.16 kg) Elastic modulus: 14,000 kg / cm ² (C-3) Olefin resin : Propylene-ethylene copolymer Mitsubishi Polypro "FG3D" MFR: 10 g / 10 minutes (230 ° C, 2.16 kg) Elastic modulus: 10,000 kg / cm ²

(D) Component (d-1) Hydrogenated diene block copolymer: linear and conjugated diene is butadiene (linear CEBC) "Dyalon 6100P" manufactured by Japan Synthetic Rubber Co., Ltd. Weight average molecular weight: 20. 30,000 terminal pseudo LDPE part (C) content: 30% by weight (D-2) hydrogenated diene block copolymer: branched and conjugated diene is butadiene (branched CEBC) "Dyalon 6160P" manufactured by Japan Synthetic Rubber Co., Ltd. Weight Average molecular weight: 226,000 Pseudo LDPE part (C) content: 17% by weight

Examples 1 to 9 and Comparative Examples 1 to 12 Phenolic antioxidants (commercial products) were added to 100 parts by weight of the total amount of the compositions blended in the blending amounts (parts by weight) shown in Tables 2 and 3. 0.1 part by weight of "Irganox 1010") is added, and a thermoplastic elastomer composition is prepared by melt-kneading at a temperature of 200 ° C. using a twin-screw extruder having L / D = 33 and a cylinder diameter of 45 mm. Of pellets were obtained. The pellets were injection molded as described above into a sheet, and the obtained sheet was subjected to the above evaluation. The evaluation results are shown in Tables 2 and 3. From the results of Examples 1 to 9 shown in Table 2, the thermoplastic elastomer composition of the present invention has flexibility, rubber elasticity, and heat resistance as compared with Comparative Examples 1 to 12 shown in Table 3.
It can be seen that the balance of molding processability is excellent, there is no bleeding of the softening agent, and the addition of the hydrogenated diene-based block copolymer results in remarkably excellent mechanical strength.

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

The thermoplastic elastomer composition of the present invention is excellent in flexibility, rubber elasticity, heat resistance, mechanical strength and molding processability, and by blending a special hydrogenated diene block copolymer, Particularly excellent in mechanical strength. The thermoplastic elastomer composition of the present invention is a material having the above-mentioned excellent properties, and is used for food, daily sundries, toys and sports equipment, stationery applications such as desk mats, automobile interior / exterior applications, and civil engineering. Civil engineering / construction applications such as sheets and waterproof sheets, AV / home appliance applications, OA / office equipment applications, clothing / footwear applications, textile applications, medical device applications such as various catheters, sanitary items such as disposable diapers / sanitary items, It can be used for chemical / mining materials, packaging / transportation materials, agricultural / livestock / fishery materials, etc.

Claims (6)

(57) [Claims] Claims: [Chemical 2] (However, C is the percentage of 20% or less of polybutadiene Nbu locks 1,2-vinyl bond, D is the proportion of vinyl bond 2
Polybut diene emission blocks is 5 to 95%, n is 1 or more, m represents 2 or more. ) Is a hydrogenated derivative of a linear polybut di <br/> ene block copolymer represented by hydrogenated poly
Butadiene-based block copolymer:
A thermoplastic elastomer composition comprising 3 to 50 parts by weight. Wherein the component (c) is an ethylene-based polymer and / or propylene-based polymer, thermoplastic elastomer composition as claimed in claim 1. Wherein (i) component of the polymer block (B) according to claim 1 or 2 thermoplastic elastomer composition wherein the hydrogenation product of 1,2-vinyl bond content 20-50% of polybutadiene. 4. The component (b) has a kinematic viscosity at 40 ° C. of 20 to 8
The thermoplastic elastomer composition according to any one of claims 1 to 3, which is a paraffinic oil having 00 cSt, a pour point of 0 to -40 ° C, and a weight average molecular weight of 300 to 2,000. 5. The component (d) is a block copolymer containing 5 to 90% by weight of block C and 95 to 10% by weight of block D, and at least 80% of double bonds are hydrogenated. The thermoplastic elastomer composition according to any one of claims 1 to 4 . 6. A chemical formula: [Chemical 4] Thermoplastic elastomer composition characterized by comprising
object.