JPH07109388A - Thermoplastic elastomer composition - Google Patents

Abstract

PURPOSE:To provide the new composition excellent in flexibility, transparency and the appearance of the molded form thereof, comprising a specific hydrogenated diene polymer and an ethylene-methyl methacrylate-based copolymer. CONSTITUTION:The composition comprising (A) 99-1wt.% of a hydrogenated diene polymer 50000-300000 in number-average molecular weight with >=80% of the double bond in the conjugated diene portion saturated (hydrogenated) and (B) 1-99wt.% of an ethylene-methyl methacrylate-based copolymer t (pref. 1-30% in methyl methacrylate fraction and 0.1-80g/10min in melt flow rate). The component A is pref. prepared by hydrogenating a block copolymer made up of aromatic vinyl polymer block and aromatic vinyl compound/conjugated diene random copolymer block. The aromatic vinyl compound is styrene; the conjugated diene is pref. butadiene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer composition, and more particularly to a thermoplastic elastomer composition excellent in flexibility, transparency and molding appearance, which is used for food, daily sundries, toys and sports equipment. Stationery applications such as desk mats, interior and exterior applications for automobiles, civil engineering and construction applications such as civil engineering sheets and waterproof sheets, AV / home appliance applications, OA / office equipment applications, clothing / footwear applications, textile applications, medical equipment applications, It can be used for chemical / mining industry materials, packaging / transportation materials, agricultural / livestock / fisheries materials, etc.

[0002]

2. Description of the Related Art Ethylene-methyl methacrylate copolymer (hereinafter abbreviated as EMMA) has a rubber elasticity, transparency,
It is characterized by being excellent in low-temperature characteristics, electrical characteristics, and low-temperature heat sealability, and is used in the above various fields.
However, there is a problem that flexibility is not sufficient. Generally, in order to improve the flexibility of EMMA, a blend of a soft elastomer such as ethylene-propylene rubber and a softening agent such as an oil / plasticizer are added. However, when a soft elastomer such as ethylene-propylene rubber is blended, there is a problem that the transparency of the obtained composition decreases. Further, when a softening agent such as an oil or a plasticizer is added, the softening agent bleeds on the surface of the obtained molded product, and there is a problem that the molding appearance is impaired, and the usable amount of the softening agent is limited, As a result, there is a problem that only a hard molded product can be obtained.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a novel elastomer composition excellent in flexibility, transparency and molded appearance.

[0004]

As a result of research, the present inventors were surprised to find that an elastomer composition excellent in flexibility, transparency and molded appearance can be obtained by combining a hydrogenated diene polymer and EMMA. The facts that should be found were found and the present invention was completed.

That is, according to the present invention, (a) a hydrogenated diene polymer having a number average molecular weight of 50,000 to 300,000 in which the double bond of the conjugated diene portion of the conjugated diene polymer is saturated by 80% or more. A thermoplastic elastomer composition comprising 99 to 1% by weight and (B) an ethylene-methylmethacrylate copolymer of 1 to 99% by weight, and the component (A) is a hydrogenated diene-based copolymer shown below. The above-mentioned thermoplastic elastomer composition is provided.

Vinyl aromatic compound polymer block (A)
(A)-(B) or (A)-(B)-(A) block copolymer comprising a random copolymer block (B) of a vinyl aromatic compound and a conjugated diene, or a vinyl aromatic compound A tapered block (C) in which vinyl aromatic compound gradually increases (A)
(B)-(C) block copolymer, wherein the weight ratio of vinyl aromatic compound / conjugated diene is 5/95 to 4
0/60, the content of the vinyl aromatic compound in the components (A) and (C) is 3 to 25% by weight based on the total amount of the monomers, and the content of the vinyl aromatic compound in the component (A) is at least the content of all the monomers. 3% by weight or more, hydrogenated block copolymer in which the vinyl bond content of the conjugated diene moiety in the component (B) is 15 to 60%, and the double bond of the conjugated diene moiety was saturated by 80% or more. A hydrogenated diene-based copolymer having an average molecular weight of 50,000 to 300,000. Hereinafter, the present invention will be described in detail.

In the component (a) of the present invention, the hydrogenation rate of the double bond in the conjugated diene portion of the conjugated diene polymer is 80% or more, preferably 90% or more, more preferably 95% or more, and the number average is It is a hydrogenated diene polymer having a molecular weight of 50,000 to 300,000, preferably 70,000 to 250,000. If the hydrogenation rate is less than 80%, the transparency is poor. Number average molecular weight is 5
If it is less than 10,000, the transparency will be lowered, and if it exceeds 300,000, the fluidity, processability, molding appearance and transparency will be poor.

Examples of the component (a) include homopolymers of conjugated dienes, random copolymers of conjugated dienes and vinyl aromatic compounds, block copolymers of polymer blocks of vinyl aromatic compounds and polymer blocks of conjugated dienes. Polymer,
It is a hydrogenated product of a diene polymer such as a block copolymer composed of a vinyl aromatic compound polymer block and a vinyl aromatic compound / conjugated diene copolymer block.
The component (a) is preferably a hydrogenated block copolymer containing a conjugated diene and a vinyl aromatic compound as essential components, and more preferably the hydrogenated diene-based copolymer according to claim 2. When used, a thermoplastic elastomer composition having more excellent flexibility, transparency and molding appearance can be obtained. The description of the component (a) of the present invention will be given below by taking the hydrogenated diene-based copolymer as defined in claim 2 as an example.

The vinyl aromatic compound constituting the hydrogenated diene copolymer is styrene, α-methylstyrene,
Examples thereof include p-methylstyrene and the like, which may be used alone or in combination, and examples of the conjugated diene include butadiene and isoprene, and butadiene is particularly preferable.

The component (A) is a polymer block mainly composed of a vinyl aromatic compound, and is copolymerized with another copolymerizable vinyl compound, preferably 10% by weight or less, more preferably 5% by weight or less. Good.

The preferred weight ratio of vinyl aromatic compound / conjugated diene is 5/95 to 40/60, more preferably 7/93 to 40/60. Less than 5% by weight of vinyl aromatic compounds (more than 95% by weight of conjugated dienes)
Then, the strength and heat resistance are inferior, and when the obtained hydrogenated diene-based copolymer is pelletized, blocking tends to occur, and when blended with EMMA, the molding appearance is inferior. If the vinyl aromatic content exceeds 40% by weight (the conjugated diene content is less than 60% by weight), it becomes resin-like and the impact resistance, low temperature characteristics and transparency are poor.

The preferred bond content of the vinyl aromatic compound in the component (A) or (C) is 3 to 25% by weight, more preferably 5 to 20% by weight, based on the total monomers.
The vinyl aromatic bond content of the components (A) and (C) is 3
If it is less than 10% by weight, blocking will occur when the obtained hydrogenated diene-based copolymer is pelletized.
When blended with A, the molding appearance is inferior, while when it exceeds 25% by weight, transparency, flexibility and low temperature properties are inferior. In addition, the content of the vinyl aromatic compound in the component (A) is preferably at least 3% by weight, more preferably 5 to 1%.
It is 5% by weight. When the vinyl aromatic bond content of the component (A) is less than 3% by weight, the molding appearance is poor when blended with EMMA.

The preferred vinyl bond content of the conjugated diene moiety in component (B) is 15-60%, more preferably 20.
~ 55%. If it is less than 15%, the flexibility improving effect and the transparency are poor when blended with EMMA. On the other hand, 60%
If it exceeds, the transparency is poor. The hydrogenation rate of the double bond of the conjugated diene portion is 80% or more, preferably 90% or more, more preferably 95% or more. If it is less than 80%, the transparency is poor.

The number average molecular weight of the hydrogenated diene copolymer is 5
It is from 10,000 to 300,000, preferably from 70,000 to 250,000.
If it is less than 50,000, the transparency will decrease, and if it exceeds 300,000, the fluidity, processability, molding appearance and transparency will be poor. The hydrogenated diene-based copolymer of the present invention is produced by living anion polymerization and further hydrogenation, as disclosed in JP-A-2-305814.

The hydrogenated diene-based copolymer used in the present invention is
It may be a block copolymer in which the polymer molecular chain is extended or branched as represented by the following general formula by adding a coupling agent. [(A)-(B)] n-X, [(A)-(B)-(C)] n-X, or [(A)-(B)-(A)] n-X (wherein , (A), (B), and (C) are the same as above, and n is 2
~ 4, X represents a coupling agent residue. ) Examples of the coupling agent at this time include diethyl adipate, divinylbenzene, methyldichlorosilane, and silicon tetrachloride.

The hydrogenated diene (co) polymer used in the present invention may be modified with a functional group and is selected from an acid anhydride group, a carboxyl group, a hydroxyl group, an amino group, an isocyanate group and an epoxy group. The unsaturated compound having at least one kind of functional group can be used for modification with a kneader, a mixer, an extruder or the like.

The blending amount of the component (a) in the thermoplastic elastomer composition of the present invention is 1 to 99% by weight, preferably 5 to 90% by weight, more preferably 5 to 80% by weight. If it is less than 1% by weight, the flexibility is inferior, and if it exceeds 99% by weight, the transparency and molding appearance are inferior.

Next, as the EMMA constituting the component (b), the copolymerization amount of methyl methacrylate is 0.5 to 40.
The amount by weight is preferably, and more preferably 1 to 30% by weight. As the third component other than methyl methacrylate, for example, α-olefins other than ethylene such as propylene and butene-1, as well as vinyl acetate, acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate,
It may contain 10% by weight or less, preferably 5% by weight or less of t-butyl acrylate, methyl methacrylate, styrene and the like. The preferred melt flow rate of EMMA is 0.01 to 100 g / min, more preferably 0.1 to 80 g / 10 min. The blending amount of the component (b) in the thermoplastic elastomer composition of the present invention is 99-1.
%, Preferably 95 to 10% by weight, more preferably 95 to 20% by weight. If it exceeds 99% by weight, flexibility is poor, and if it is less than 1% by weight, transparency and molding appearance are poor.

The thermoplastic elastomer composition of the present invention comprises
If necessary, cross-linking such as sulfur cross-linking, peroxide cross-linking, metal ion cross-linking, and silane cross-linking can be performed by a conventionally known method.

The thermoplastic elastomer composition of the present invention may be used in addition to the above-mentioned components (a) and (b) depending on the application.
Flexibility, transparency, antioxidizing agent, antistatic agent, weathering agent, ultraviolet absorber, slip agent, antiblocking agent, sealability improving agent, crystal nucleating agent in an amount that does not hinder the appearance of molding.
Flame retardant, cross-linking agent, co-cross-linking agent, vulcanizing agent, vulcanization aid, antibacterial / antifungal agent, dispersant, tackifier, softening agent, plasticizer, viscosity modifier, anti-coloring agent, foaming Agents, coloring agents such as titanium oxide and carbon black, metal powders such as phyllite, inorganic fibers such as glass fibers and metal fibers, organic fibers such as carbon fibers and aramid fibers, glass beads, glass balloons, glass flakes, asbestos, mica Inorganic whiskers such as calcium carbonate and potassium titanate whiskers, talc, silica, calcium silicate, kaolin, diatomaceous earth, graphite, pumice stone, evo powder, cotton flock, cork powder, barium sulfate, fluororesin, polymer beads, etc. Fillers, other rubbery polymers, thermoplastic resins and the like can be appropriately blended.

The composition of the present invention can be obtained by melt-kneading with a conventionally known kneader such as an extruder, a kneader or a Banbury mixer, or by dry blending with an injection molding machine. In order to produce the composition of the present invention, the respective components may be mixed at once, or the optional components may be premixed in advance and then the remaining components may be added and mixed. The most preferable mixing device is a single-screw or twin-screw extruder, which allows efficient and continuous kneading and pelletization.

The composition of the present invention can be processed into a practically useful molded product by a conventionally known method such as extrusion molding, injection molding, blow molding, compression molding or calender molding. Further, if necessary, processing such as foaming, powdering, drawing, adhesion, printing, painting, and plating can be performed. Examples of the extrusion-molded article obtained by using the composition of the present invention include a sheet, a film, a tube, a shaped article, a net and a block, which can be used for various purposes.

[0023]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, parts and% are based on weight unless otherwise specified. Moreover, various measurements and evaluations in Examples and Comparative Examples were based on the following methods.

Based on the absorption of a phenyl group having a content of a bound vinyl aromatic compound of 679 cm ⁻¹ , it was measured by an infrared analysis method. Vinyl bond content of conjugated diene Calculated by Hampton method using infrared analysis. Hydrogenation rate Using tetrachloroethylene as a solvent, 100 MHz, ¹ H-N
It was calculated from the MR spectrum. Number-Average Molecular Weight of Hydrogenated Diene Copolymer Trichlorobenzene was used as a solvent, and it was determined in terms of polystyrene using gel permeation chromatography (GPC) at 135 ° C. Transparency Using a multi-source spectrophotometer manufactured by Suga Test Co., Ltd., JIS
The haze was measured according to K6714. Sample is 2m
A m-thick compression molded sheet was used. Flexibility JIS A hardness was measured according to JIS K6301. Molding appearance The molded products were visually evaluated according to the following criteria. ◯: Appearance is good. Δ: The appearance is slightly inferior. X: Poor appearance such as pearly luster, flow mark, and rough surface.

Reference Example Various components used in the formulation of Examples, Comparative Examples and evaluations are as follows. EMMA ethylene-methyl methacrylate copolymer [Acrylift WH202, manufactured by Sumitomo Chemical Co., Ltd.] (methyl methacrylate amount: 20% by weight, melt flow rate: 3 g / 10
min) EPM ethylene-propylene rubber [manufactured by Nippon Synthetic Rubber Co., Ltd., E
P07P] SEBS polystyrene - polybutadiene - block copolymer obtained by hydrogenating a polybutadiene moiety of the polystyrene copolymer [Shell Chemical Co., Ltd., Kraton G1650] softener paraffin oil [Idemitsu Kosan Co., Ltd., PW380] Hydrogenated Diene Copolymer Hydrogenated diene copolymers (T-1 to 15) are manufactured by Nippon Synthetic Rubber Co., Ltd. and have a microstructure of T-1 to 15,
The number average molecular weight and the hydrogenation rate are as shown in Table 1.

Examples 1 to 15 and Comparative Examples 1 to 7 The performances of the elastomer compositions having the compositions shown in Tables 2 and 3 were evaluated, and the results are shown in the same table. Example 1 shown in Table 2
8 and the results of Examples 9 to 15 shown in Table 3 show that the elastomer composition of the present invention is superior in flexibility, transparency, and molding appearance to Comparative Examples 1 to 7 shown in Table 3.
In Comparative Examples 1 and 2, the compounding ratio is out of the range of the present invention, so that the balance of flexibility, transparency, and molding appearance is poor. Comparative Example 3 is an example in which a hydrogenated diene-based copolymer having a number average molecular weight less than the range of the present invention is used as the component (a), while Comparative Example 4 is a hydrogenated diene-based copolymer in which the number average molecular weight exceeds the range. In both cases, the transparency and molding appearance are inferior. Comparative Example 5
Is an example in which a hydrogenated diene-based copolymer having a hydrogenation rate of less than the range of the present invention is used as the component (a), and the transparency is poor. Comparative Example 6 is an example in which a commercially available EP is used instead of the hydrogenated diene-based copolymer as the component (a), and the transparency and the molding appearance are poor, which is not preferable. Comparative Example 7 is an example in which a commercially available softening agent was used instead of the hydrogenated diene-based copolymer as the component (a), and the softness, transparency, and molding appearance were poorly balanced, and the softening agent bleeded on the surface. And is not preferable.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

The thermoplastic elastomer composition of the present invention has essentially the same physical properties as the thermoplastic elastomer composition, and is excellent in flexibility, transparency and molded appearance. The thermoplastic elastomer composition of the present invention is a material having excellent properties as described above, food applications, daily sundries applications,
Toys and sports equipment applications, stationery applications such as desk mats, automotive interior and exterior applications, civil engineering sheets, waterproof sheets, etc.
Building use, AV / home electric appliance use, OA / office equipment use,
It is an industrially valuable material that can be used for clothing / footwear, textiles, medical equipment, chemical / mining materials, packaging / transportation materials, agricultural / livestock / fishery materials, etc.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshihisa Fujinaga 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd.

Claims (2)

[Claims] 1. (a) 99-1 weight of a hydrogenated diene polymer having a number average molecular weight of 50,000 to 300,000, in which a double bond of a conjugated diene portion of the conjugated diene polymer is saturated by 80% or more. %, (B) an ethylene-methyl methacrylate copolymer 1 to 99% by weight, a thermoplastic elastomer composition. 2. The thermoplastic elastomer composition according to claim 1, wherein the component (a) according to claim 1 is a hydrogenated diene-based copolymer shown below. Vinyl aromatic compound polymer block (A)
(A)-(B) or (A)-(B)-(A) block copolymer comprising a random copolymer block (B) of a vinyl aromatic compound and a conjugated diene, or a vinyl aromatic compound A tapered block (C) in which vinyl aromatic compound gradually increases (A)
(B)-(C) block copolymer, wherein the weight ratio of vinyl aromatic compound / conjugated diene is 5/95 to 4
0/60, the content of the vinyl aromatic compound in the components (A) and (C) is 3 to 25% by weight based on the total amount of the monomers, and the content of the vinyl aromatic compound in the component (A) is at least the content of all the monomers. 3% by weight or more, hydrogenated block copolymer in which the vinyl bond content of the conjugated diene moiety in the component (B) is 15 to 60%, and the double bond of the conjugated diene moiety was saturated by 80% or more. A hydrogenated diene-based copolymer having an average molecular weight of 50,000 to 300,000.