JP6994421B2 - Thermoplastic elastomer composition - Google Patents

Description

The present invention relates to a thermoplastic elastomer composition used for various molded products such as automobile parts, electrical / electronic equipment parts, medical tools, building materials / piping members, daily life / cosmetic products, and composite molded products using the compositions. ..

A thermoplastic elastomer composition containing an acrylic elastomer and a styrene elastomer has been proposed as a composition useful for various molded products such as automobile parts, electrical / electronic equipment parts, medical tools, building materials / piping members, and daily / cosmetic products. Has been done. This thermoplastic elastomer composition is required to have various physical properties depending on the use of the molded product. For example, in order to use it for a game controller or a grip rubber of a toothbrush, it is necessary to obtain good moldability, heat fusion to polar resins such as polyacetal (POM) constituting the composite material body, and good tactile sensation. High flexibility is required.

In Patent Document 1, a controlled distribution type styrene block copolymer is used as a flow modifier for improving the processability of a polymer compound, and the fluidity is improved by increasing the blending ratio, which makes it easier. It is disclosed that a high-performance rubber compound that can be processed into a high-performance rubber compound can be produced.

In Patent Document 2, a thermoplastic elastomer composition containing an acrylic resin and a softening agent in a hydrogenated styrene-based block copolymer not only has heat-sealing properties with a polar resin such as ABS resin, but also has flexibility. It is disclosed that it is excellent in.

Patent Document 3 describes a polyacetal resin adhesive obtained by adding a urethane thermoplastic elastomer and a petroleum resin to a resin composition containing an organic peroxide and a carboxylated liquid polybutadiene in a hydrogenated styrene block copolymer. The thermoplastic resin composition and Patent Document 4 disclose that a styrene-based thermoplastic elastomer or a thermoplastic polymer composition containing an olefin-based thermoplastic elastomer and polyvinyl acetal is fused to polyacetal (POM). Has been done.

Japanese Unexamined Patent Publication No. 2007-84421 Japanese Unexamined Patent Publication No. 2001-81276 Japanese Unexamined Patent Publication No. 2010-1479 International Publication No. 2009/081877

However, Patent Document 1 discloses that the controlled distribution type styrene-based block copolymer can be used as a flow modifier and can produce a high-performance rubber compound that can be easily processed. There is no description about wearability, and its performance is uncertain.

In Patent Document 2, by using an acrylic resin or a hydrocarbon-based rubber softener for a styrene-based block copolymer that is not a controlled distribution type, heat-sealing properties can be obtained in polar resins, especially for ABS. Although it is disclosed that it is shown, the effect is not clear because there is no description about the heat-sealing property with polyacetal (POM).

Further, Patent Documents 3 and 4 evaluate the heat-sealing property with polyacetal (POM) by a 180-degree peeling test, but higher adhesive strength is desired.

An object of the present invention is to provide a thermoplastic elastomer resin composition having excellent heat-sealing properties with polyacetal (POM) and a composite molded product using the composition.

As a result of various studies by the present inventors on the above-mentioned problems, the controlled distribution type styrene block copolymer has heat-sealing property to the polar resin, and further, the (meth) acrylic block copolymer is used in combination. By doing so, it was found that good heat-sealing properties and moldability with respect to polyacetal (POM) can be obtained, and the present invention has been completed.

The present invention
[1] A thermoplastic elastomer containing a controlled distribution type styrene block copolymer A and a (meth) acrylic block copolymer B in a mass ratio (A / B) of 30/70 to 90/10. The present invention relates to the composition and [2] a composite molded body in which the thermoplastic elastomer composition according to the above [1] and polyacetal are heat-sealed.

The thermoplastic elastomer resin composition of the present invention is effective in heat-sealing property with polyacetal (POM).

The thermoplastic elastomer composition of the present invention has a controlled distribution type styrene block copolymer A and a (meth) acrylic block copolymer B, and has mechanical properties such as rigidity and toughness, abrasion resistance, and sliding. It is characterized by having heat-sealing property to polyacetal (POM), which is known to have poor adhesiveness and heat-sealing property while having excellent motility. In addition, "heat fusion" is to apply heat above the melting point to the thermoplastic elastomer composition, heat-fuse it to the adherend in a molten state, and solidify it at a temperature below the melting point. It refers to the phenomenon of sticking to the interface of a target, and in the present invention, a material having a peel strength of 30 N / 25 mm or more measured by the test method described later is defined as having "heat fusion property".

The content of the styrene-based monomer unit in the controlled distribution type styrene-based block copolymer A is preferably 45% by mass or more, more preferably 50% by mass or more, and further, from the viewpoint of heat-sealing property to the polar resin. It is preferably 55% by mass or more, preferably 80% by mass or less, more preferably 75% by mass or less, and further preferably 70% by mass or less from the viewpoint of flexibility. The content of the styrene-based monomer unit in the controlled distribution type styrene-based block copolymer A is the total amount of the styrene-based monomer unit in the hard segment and the styrene-based monomer unit in the soft segment. When two or more types of controlled distribution type styrene-based block copolymer A are used in combination, the weighted average value of the content of the styrene-based monomer in each block copolymer is set as the styrene-based single amount. The content is per body unit.

In the present invention, the styrene-based monomer includes not only styrene but also o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene and the like having 1 carbon atom. Also included are styrene derivatives substituted with up to 4 alkyl groups.

The controlled distribution type styrene-based block copolymer A preferably has a hard segment and a soft segment from the viewpoint of flexibility and moldability. For example, the block unit (as a hard segment) which is a polymerization unit of the styrene-based monomer ( Examples thereof include a block copolymer Z composed of a block unit S) and a block unit (block unit B) having a controlled distribution structure, which is a copolymerization unit of a conjugated diene and a styrene-based monomer as a soft segment.

The mass ratio (hard segment / soft segment) of the hard segment to the soft segment in the controlled distribution type styrene block copolymer A is preferably 45/55 to 80/20, more preferably 50/50 to 65/35. ..

Examples of the conjugated diene include butadiene, isoprene, 1,3-pentadiene and the like.

It is preferable that the block copolymer Z has a structure of [block unit S-block unit B] m-block unit S type. Here, m is preferably 1 to 5, but in the present invention, a triblock copolymer having m of 1 is preferable.

The block unit B has two or more regions containing a conjugated diene unit as a main constituent unit and one or more regions containing a styrene-based monomer unit as a main constituent unit, and both ends adjacent to the block unit S. Is preferably a region containing a conjugated diene unit as a main constituent unit.

It is preferable that the block copolymer Z is hydrogenated with a part or all of the unsaturated bond of the conjugated diene monomer unit. By hydrogenating the unsaturated bond of the conjugated diene monomer unit, the unsaturated bond is reduced and the heat resistance, weather resistance and mechanical properties are improved. The hydrogenation rate is preferably 80% or more, more preferably 90% or more. In the present invention, the hydrogenation rate is measured by measuring the content of carbon-carbon double bonds derived from the conjugated diene monomer in the thermoplastic styrene elastomer A by ¹ H-NMR spectrum before and after hydrogenation. , Can be obtained from the measured value.

The hydrogenated substance of the block copolymer Z having a triblock structure in which the conjugated diene is butadiene is called controlled distribution SEBS, and as a commercially available product of controlled distribution SEBS, for example, A series manufactured by Kraton Polymer Co., Ltd., MD series and the like can be mentioned.

The controlled distribution type styrene block copolymer is well known in the art, and is described in, for example, Japanese Patent Application Laid-Open No. 2007-84421, Japanese Patent Application Laid-Open No. 2013-518170, and the like.

The weight average molecular weight of the controlled distribution type styrene block copolymer A is preferably 100,000 or more, more preferably 200,000 or more from the viewpoint of heat-sealing property to the polar resin, and preferably 500,000 from the viewpoint of moldability. Below, it is more preferably 450,000 or less, still more preferably 350,000 or less. When two or more kinds of controlled distribution type styrene block copolymers A are used in combination, the weighted average value of the weight average molecular weight of each styrene rock copolymer is defined as the weight average molecular weight.

Examples of the (meth) acrylic monomer constituting the (meth) acrylic block copolymer B include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic. Butyl acid, phenyl (meth) acrylic acid, 2-ethylhexyl (meth) acrylic acid, cyclohexyl (meth) acrylic acid, (meth) acrylic acid, hydroxyethyl (meth) acrylic acid, hydroxypropyl (meth) acrylic acid, (meth) ) Glycidyl acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate and the like. In the present specification, unless otherwise specified, the alkyl group name without a subscript contains isomers such as n-, iso-, sec-, and tert-, and when it is indicated as (meth) acrylic, it is methacrylic. And acrylic.

The amount of the (meth) acrylic monomer is preferably 20% by mass or more, more preferably 50% by mass or more, and further preferably 80% by mass or more among the monomers constituting the (meth) acrylic block copolymer B. preferable.

Examples of other copolymerizable monomers include vinyl monomers such as styrene, α-methylstyrene, vinyl acetate, ethylene, propylene, butadiene, isoprene, and maleic anhydride. Among these, styrene and the like. α-Methylstyrene and ethylene are preferable, and these monomers are used in combination within a range that does not impair the object of the present invention (preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 10% by mass or less). It may have been done.

Examples of the method for polymerizing the monomer for obtaining the (meth) acrylic block copolymer B include a radical polymerization method, a living anion polymerization method, and a living radical polymerization method. Moreover, as a form of polymerization, for example, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method and the like can be mentioned.

The (meth) acrylic block copolymer B is preferably a block copolymer having two or more blocks constituting the hard segment and one or more blocks constituting the soft segment, and is preferably a block copolymer constituting the soft segment. More preferably, it is a triblock copolymer having two blocks constituting the hard segment on both sides of one. The proportion of the triblock copolymer is preferably 60% by mass or more, more preferably 70% by mass or more in the (meth) acrylic block copolymer B. Further, the (meth) acrylic block copolymer B may contain a diblock copolymer and a multi-block copolymer in addition to the triblock copolymer.

The monomer constituting the hard segment is preferably one kind or two or more kinds of methacrylic monomers. Examples of such methacrylic acid monomer include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl acrylate, cyclohexyl methacrylate, phenyl methacrylate and methacrylic acid. Examples thereof include hydroxyethyl acetate, glycidyl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, butoxyethyl methacrylate, phenoxyethyl methacrylic acid, 2,2,2-trifluoroethyl methacrylate, and the like. Methyl methacrylic acid is more preferred.

The monomer constituting the hard segment preferably contains the methacrylic monomer, but is within a range that does not impair the object of the present invention (preferably 30% by mass or less, more preferably 20% by mass or less). More preferably, it is 10% by mass or less) and may contain an acrylic monomer or another monomer. Further, it can be made into a hard segment by increasing the molecular weight by a polymerization reaction.

Examples of the copolymerizable monomer include ethylene, propylene, α-olefin, styrene, α-methylstyrene, acrylonitrile, parahydroxystyrene, vinyl alcohol, acrylic acid, methacrylic acid, acrylamide, metaacrylamide, and methylvinyl ether. Examples thereof include vinyl monomers such as vinylbenzoate, maleic acid and N-cyclohexylmaleimide, and among these, styrene, α-methylstyrene and ethylene are preferable.

In order for the (meth) acrylic block copolymer B to exhibit its properties as a thermoplastic elastomer, it is preferable that the (meth) acrylic block copolymer B has a hard segment having a glass transition temperature of room temperature or higher.

The glass transition temperature of the block constituting the hard segment is preferably 20 to 200 ° C, more preferably 30 to 180 ° C, still more preferably 50 to 150 ° C, from the viewpoint of maintaining the toughness of the composition in the normal temperature range. If the glass transition temperature of the blocks constituting the hard segment is too low, the obtained composition may have insufficient heat resistance, and it is difficult to obtain raw materials for blocks having a glass transition temperature exceeding 200 ° C.

The vinyl monomer constituting the soft segment is preferably one kind or two or more kinds of acrylic monomers. As the acrylic monomer, ethyl acrylate, butyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, benzyl acrylate, phenylethyl acrylate and the like are preferable because of their high reactivity with the ester exchange catalyst.

The glass transition temperature of the blocks constituting the soft segment is preferably -100 to 19 ° C, more preferably -80 to 10 ° C, still more preferably -70 to 0 ° C. If the glass transition temperature of the blocks constituting the soft segment is too high, the obtained composition may lack flexibility, and it is difficult to obtain raw materials for blocks having a glass transition temperature lower than -100 ° C.

Examples of the acrylic monomer constituting the soft segment having a glass transition temperature of 19 ° C or less include n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, n-hexyl acrylate, ethyl hexyl acrylate, and acrylic acid. At least one selected from the group consisting of n-heptyl, n-octyl acrylate and phenylethyl acrylate is preferable, and n- acrylate n- from the viewpoint of being difficult to be compatible with the above-mentioned hard segment and easily forming a phase-separated structure. At least one selected from the group consisting of propyl, n-butyl acrylate, n-hexyl acrylate, n-heptyl acrylate and n-octyl acrylate is more preferable, and n-butyl acrylate is even more preferable.

The monomer constituting the soft segment preferably contains the acrylic monomer, but is within a range that does not impair the object of the present invention (preferably 30% by mass or less, more preferably 20% by mass or less). More preferably, it is 10% by mass or less) and may contain a methacrylic monomer or another monomer.

As a method for measuring the glass transition temperature of a polymer, differential scanning calorimetry (DSC), dynamic viscoelasticity measurement, thermal expansion measurement (TMA) and the like are known, but in the present invention, a hard segment and a soft segment are known. In a block copolymer containing both of these, dynamic viscoelasticity measurement is a common method that can accurately measure both hard segment and soft segment values, and viscoelasticity measurement is performed at different temperatures. , A method of determining the glass transition temperature from the peak of the dielectric normal contact Tan δ is known. Therefore, the glass transition temperature measured by dynamic viscoelasticity measurement is used as the glass transition temperature of the hard segment and the soft segment in the present invention.

The mass ratio (hard segment / soft segment) of the hard segment to the soft segment in the (meth) acrylic block copolymer B is preferably 10/90 to 70/30, preferably 15 /, from the viewpoint of imparting appropriate flexibility. 85-60/40 is more preferred.

Examples of commercially available products that can be used as the (meth) acrylic block copolymer B include Clarity manufactured by Kuraray Co., Ltd., Nanostrength manufactured by Arkema Co., Ltd., and the like.

The weight average molecular weight of the (meth) acrylic block copolymer B is preferably 20,000 or more, more preferably 30,000 or more, still more preferably 40,000 or more, from the viewpoint of mechanical properties such as tensile strength. Further, from the viewpoint of easy handling and maintaining a melt viscosity suitable for manufacturing a molded product such as injection molding, 500,000 or less is preferable, 400,000 or less is more preferable, and 200,000 or less is further preferable. From these viewpoints, the weight average molecular weight of the component A is preferably 20,000 to 500,000, more preferably 30,000 to 400,000, and even more preferably 40,000 to 200,000.

Further, in the relationship between the weight average molecular weight (Mw) and the number average molecular weight (Mn), Mw / Mn is used.
1 to 5 is preferable, and 1.05 to 3 is more preferable.

The A hardness of the (meth) acrylic block copolymer B is preferably 20 to 80, more preferably 25 to 70, and even more preferably 30 to 67, from the viewpoint of the flexibility of the composition.

In the thermoplastic elastomer composition of the present invention, when the content of the (meth) acrylic block copolymer B exceeds a certain amount, the releasability deteriorates. From this point of view, the mass ratio (A / B) of the controlled distribution type styrene block copolymer A and the (meth) acrylic block copolymer B in the thermoplastic elastomer composition of the present invention is 30/70 to 90 /. It is 10, preferably 35/65 to 85/15, and more preferably 40/60 to 80/20.

The total content of the controlled distribution type styrene block copolymer A and the (meth) acrylic block copolymer B is preferably 70% by mass or more, more preferably 80% by mass or more in the thermoplastic elastomer composition. It is preferably 99.8% by mass or less, and more preferably 90% by mass or less.

From the viewpoint of flexibility and heat-sealing property, the thermoplastic elastomer composition of the present invention preferably further contains a plasticizer C.

The plasticizer C is preferably at least one selected from the group consisting of paraffin oil, naphthenic oil, and aromatic oil, and among these, the affinity with the controlled distribution type styrene block copolymer A is high. Paraffin oil is more preferable from the viewpoint of good quality and less bleeding.

The higher the kinematic viscosity of the plasticizer ^C at 40 ° C., the ^more it prevents volatilization during heating and melting, and the better the bleed resistance. It is more preferably 80 mm ² / s or more, and further preferably 150 mm ² / s or more from the viewpoint of improving the heat fusion property to the polar resin, and a lower value is preferably 500 mm ² / s because it is easy to handle. It is / s or less, more preferably 450 mm ² / s or less, still more preferably 400 mm ² / s or less.

The content of the plasticizer C is preferably 1 part by mass or more from the viewpoint of flexibility with respect to 100 parts by mass of the total amount of the controlled distribution type styrene block polymer A and the acrylic block copolymer B. It is preferably 10 parts by mass or more, preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and further preferably 30 parts by mass or less from the viewpoint of preventing oil bleeding and heat-sealing property to the polar resin.

The content of the plasticizer C in the thermoplastic elastomer composition is preferably 5 to 45% by mass, more preferably 10 to 40% by mass.

The thermoplastic elastomer composition of the present invention may contain an elastomer other than the controlled distribution type styrene-based block copolymer A and the (meth) acrylic-based block copolymer B, and if necessary, the present invention. Reinforcing agents such as carbon black, silica, carbon fiber, glass fiber, inorganic filler, insulating heat conductive filler, pigment, hydrated metal compound, red phosphorus, ammonium polyphosphate, antimony, as long as the effect of the invention is not impaired. , Flame retardants such as silicones, antistatic agents, thickeners, tackifiers, cross-linking agents, cross-linking aids, heat stabilizers, antioxidants, light stabilizers, UV absorbers, blocking inhibitors, sealability improvers , Various additives such as a mold release agent, a colorant, and a fragrance may be contained.

In the thermoplastic elastomer composition of the present invention, a raw material containing a controlled distribution type styrene block copolymer A, a (meth) acrylic block copolymer B, and a plasticizer C or the like, if necessary, is mixed and cooled. Obtained by solidifying.

The "mixing" referred to in the present invention is not particularly limited as long as it is a method in which various components are well mixed, and the various components may be dissolved in a soluble organic solvent and mixed, or by melt kneading. Although they may be mixed, the raw materials are preferably mixed under conditions where the raw materials melt, preferably under conditions where the (meth) acrylic block copolymer B melts.

In the case of melt-kneading, a general extruder can be used, and it is preferable to use a twin-screw extruder in order to improve the kneading state. For supply to the extruder, a mixture of various components in advance using a mixing device such as a Henschel mixer may be supplied from one hopper, or each component is charged in two hoppers and quantified with a screw or the like under the hopper. You may serve while doing so.

The product obtained by mixing the raw materials constituting the thermoplastic elastomer composition can be in the form of pellets, sheets, or the like, depending on the intended use. For example, it is melt-kneaded by an extruder and extruded into a strand, and while being cooled in cold water, it is cut into pellets such as cylinders and rice granules by a cutter. The obtained pellets are usually made into a predetermined sheet-shaped molded product or molded product by injection molding or extrusion molding. Further, the melt-kneaded product can be pelletized with a ruder or the like and used as a raw material for molding.

The A hardness of the thermoplastic elastomer composition of the present invention is preferably 90 or less, more preferably 85 or less, still more preferably 80 or less from the viewpoint of flexibility, and preferably from the viewpoint of stickiness suppression and practicality. Is 40 or more, more preferably 50 or more, still more preferably 55 or more.

A molded product can be obtained by appropriately heat-molding the thermoplastic elastomer composition of the present invention according to a conventional method. The application of the molded product obtained by heat-molding the thermoplastic elastomer composition of the present invention is not particularly limited, and fields in which general styrene-based elastomers, (meth) acrylic-based elastomers, polyolefin-based elastomers, and the like are used. Can be used for.

As the apparatus used for producing a molded product using the thermoplastic elastomer composition of the present invention, any molding machine capable of melting the molding material can be used. For example, an extrusion molding machine, an injection molding machine, a press molding machine, a blow molding machine, a mixing roll and the like can be mentioned.

Since the thermoplastic elastomer composition of the present invention is fused to various materials, it can also be suitably used for laminating members made of different materials. For example, it is used for fusion to at least one member selected from the group consisting of metal, ceramic, glass and polar resin, and exhibits particularly good thermal fusion property to polar resins and the like.

The metal is not particularly limited, and examples thereof include aluminum, aluminum alloys, stainless steel, iron, copper, zinc-plated steel, magnesium, magnesium alloys, and various plated products.

Examples of the polar resin include polyester resins such as polyacetal and polybutylene terephthalate, poly (meth) acrylate resins such as polycarbonate and polymethylmethacrylate, polyethylene oxide resins, polypropylene oxide resins, polyvinyl acetate resins and polyamides. Polyester resin, polyurethane resin, polystyrene resin such as ABS resin, polyvinyl ether resin, polyvinyl alcohol resin, polyphenylene ether resin, polyphenylene sulfide resin, polysulfone resin, polyetherimide resin, polyether ketone resin, polyether ether Examples thereof include a ketone resin, a polar resin such as LCP (liquid crystal polymer) and an ionomer, and a mixture of two or more of these. Among these, it is excellent in heat fusion property with polyacetal, which has been difficult to heat fusion in the past.

As a means for applying heat for heat-sealing the thermoplastic elastomer, a hot press machine, a heating roll machine, a hot air generator, a heated steam, an ultrasonic welder, a high frequency welder, a laser and the like can be used.

Therefore, the thermoplastic elastomer composition of the present invention can be integrated with the members such as metal, ceramic, glass, and polar resin to form a composite molded product. By heat fusion, even if the interface of the fused portion has a complicated three-dimensional shape, it can be well adapted to the complicated three-dimensional shape and integrated by molding. It is also possible to combine members having the above.

The composite molded body in which the thermoplastic elastomer composition of the present invention is heat-sealed to a member includes injection molding, injection compression molding, insert molding, multicolor molding, vacuum molding, pressure molding, blow molding, heat press molding, foam molding, and Although it can be obtained by molding by a method such as laser fusion molding or extrusion molding, the thermoplastic elastomer composition of the present invention is not sticky by itself like an adhesive and is easy to handle. Therefore, it can also be applied to injection molding.

The composite molded body in which the thermoplastic elastomer composition of the present invention is heat-sealed to a member includes an insert molded body in which a polar resin is inserted into a molded body made of the thermoplastic elastomer composition, a thermoplastic elastomer composition, and a polar resin. Examples thereof include a composite molded body obtained by multicolor molding.

The thermoplastic elastomer composition of the present invention can be used as various molded products depending on the intended use, but since it has excellent heat-sealing properties and flexibility of polar resins such as polyacetal, it can be used as a game controller or a game controller. It can be suitably used for the grip rubber of a toothbrush.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. Various physical properties of the raw materials used in Examples and Comparative Examples were measured by the following methods.

<Component A (controlled distribution type styrene block copolymer, etc.)>
[Content of styrene-based monomer unit]
The content of styrene and / or styrene derivative is determined by performing proton NMR measurement with a nuclear magnetic resonance apparatus (manufactured by BRUKER, Germany, DPX-400) and quantifying the characteristic group of styrene. The content of other monomer units can also be determined by proton NMR measurement.

[Hard segment / Soft segment (mass ratio)]
The mass ratio of the hard segment to the soft segment is measured by proton NMR measurement at 25 ° C. in a deuterated chloroform solvent using a nuclear magnetic resonance apparatus (DPX-400 manufactured by BRUKER, Germany). Calculated from the signal intensity ratio of methylene peaks adjacent to various oxygen in the structure.

[Weight average molecular weight (Mw)]
Under the following measurement conditions, the molecular weight is measured in terms of polystyrene by a gel permeation chromatograph, and the weight average molecular weight is obtained.

Measuring device / pump: JASCO (JASCO Corporation), PU-980
・ Column oven: Showa Denko KK, AO-50
・ Detector: Hitachi, RI (differential refractometer) detector L-3300
-Column type: Showa Denko Corporation "K-805L (8.0 x 300 mm)" and "K-804L (8.0 x 300 mm)" are used in series.-Column temperature: 40 ° C
・ Guard column: KG (4.6 x 10 mm)
・ Eluent: Chloroform ・ Eluent flow rate: 1.0 ml / min
・ Sample concentration: Approximately 1 mg / ml
・ Sample solution filtration: Polytetrafluoroethylene 0.45 μm pore size disposable filter ・ Standard sample for calibration curve: Polystyrene manufactured by Showa Denko KK

<Component B ((meth) acrylic block copolymer, etc.)>
[Hard segment / Soft segment (mass ratio)]
The composition ratio (mass ratio) of each polymer block in the (meth) acrylic block copolymer is determined by ¹ H-NMR ( ¹ H-nuclear magnetic resonance) measurement.
・ Equipment: BRUKER nuclear magnetic resonance device "AVANCE III"
-Deuterated solvent: Deuterated chloroform

[A hardness]
Measure according to JIS K 6253 Type A.

[Melting point]
The melting point is defined as the temperature of the melting peak obtained by raising the temperature at 10 ° C / min according to the method specified in JIS K 7121 using a differential scanning calorimetry (DSC) device. When multiple melting peaks appear, the melting peak that appears at a lower temperature is taken as the melting point.

[Glass transition temperature (Tg)]
Using a dynamic viscoelasticity measuring device (RSAIII manufactured by TA Instruments Co., Ltd.), the test piece is heated under the conditions of a temperature range of -100 to 280 ° C, a temperature rise rate of 5 ° C / min, and a frequency of 10 Hz. The peak temperature of the loss tangent (Tanδ) observed at the time of this is defined as the glass transition temperature (Tg). Use a test piece with a thickness of 2 mm, a width of 12 mm, and a length of 30 mm.
For elastomers with multiple blocks (soft segment and hard segment), multiple loss tangent peaks are usually observed, but in this case the low temperature peak is derived from the soft segment and the high temperature peak is. It is derived from the hard segment.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
Obtained from polystyrene conversion using the following equipment, column and solvent from a gel permeation chromatograph (GPC).
・ Equipment: Tosoh, HLC-8120
-Column: Inertsil WF300
・ Solvent: Tetrahydrofuran

<Component C (plasticizer)>
[Kinematic viscosity]
Measure at a temperature of 40 ° C according to JIS Z 8803.

Examples 1 to 8 and Comparative Examples 1 to 8
(1) Preparation of Thermoplastic Elastomer Composition (Pellet) The materials shown in Tables 5 and 6 other than the component C were dry-blended and impregnated with the component C to prepare a mixture. Then, the mixture is melt-kneaded with an extruder under the following conditions, extruded into strands, and cut into a diameter of about 3 mm and a thickness of about 3 mm by a cutter while being cooled in cold water to obtain pellets of the thermoplastic elastomer composition. Manufactured.

[Melting and kneading conditions]
Extruder: KZW32TW-60MG-NH (trade name, manufactured by Technobel Co., Ltd.)
Cylinder temperature: 180-220 ℃
Screw rotation speed: 300r / min

Details of the raw materials shown in Tables 5 and 6 used in Examples and Comparative Examples are as follows.

(2) Preparation of molded body of thermoplastic elastomer composition The pellet was injection molded under the following conditions to prepare a plate having a thickness of 2 mm, a width of 125 mm and a length of 125 mm.

[Injection conditions]
Injection molding machine: 100MSIII-10E (trade name, manufactured by Mitsubishi Heavy Industries, Ltd.)
Injection molding temperature: 200 ° C
Injection pressure: 30%
Injection time: 3sec
Mold temperature: 40 ℃

The injection moldability was evaluated from the state of the obtained plate and the like, and the flexibility and heat fusion property were further evaluated. The results are shown in Tables 5 and 6.

[Evaluation criteria for injection moldability]
◯: The plate is in good condition ×: The plate can be molded but bleed-out occurs from the plate XX: The plate can be molded but the mold release property is poor XX: The plate cannot be molded or Things in bad condition

[Flexibility]
Using a plate (125 mm square plate) one day after injection molding, the durometer A hardness was measured according to the method specified in JIS K 6253, and the flexibility was evaluated according to the following evaluation criteria.
<Evaluation criteria>
A Hardness is ◎: 55 or more and 80 or less ○: More than 80 and 90 or less △: Less than 55 or more than 90

[Heat fusion]
The following polar resin is inserted into a mold having a thickness of 4 mm, a width of 25 mm, and a length of 125 mm, and the thermoplastic elastomer compositions obtained in Examples and Comparative Examples are injection-molded under the following conditions to melt them into strips. A wearing test piece was prepared.

<Insert material (polar resin)>
(1) Size: Thickness 2 mm x Width 25 mm x Length 120 mm
(2) Type-Polyacetal (POM): Duracon M90-44 (manufactured by Polyplastics)
-Polycarbonate (PC): Upiron H-3000, manufactured by Mitsubishi Engineering Plastics

<Injection molding conditions>
Injection molding machine: Mitsubishi Heavy Industries, Ltd., 100MSIII-10E
Injection molding temperature: 260 ° C (POM) or 240 ° C (PC)
Injection pressure: 98MPa, injection speed: 50%, holding pressure: 20%, holding time: 10sec
Injection time: 2sec
Mold temperature: 40 ℃

Using the obtained fusion test piece, the peel strength was measured at an atmospheric temperature of 23 ° C. in accordance with JIS K6854-2 "Adhesive peeling adhesion strength test method (180 degree peeling)". Using the thermoplastic elastomer layer as a flexible adherend and the polar resin layer as a rigid adherend, a tensile test was conducted on the elastomer layer at 50 mm / min in the 180 ° direction, and the peel strength between the skin material layer and the base material layer (unit:: N / 25mm) was measured, and the heat fusion property was evaluated according to the following evaluation criteria.

<Evaluation criteria>
Peeling strength is 〇: 30N / 25mm or more ×: less than 30N / 25mm

From the above results, the thermoplastic elastomer compositions of Examples 1 to 8 have good flexibility and are superior in moldability as compared with the thermoplastic elastomer compositions of Comparative Examples 1, 2 and 5. I understand. Further, it can be seen that the heat-sealing property to polyacetal is excellent as compared with the thermoplastic elastomer compositions of Comparative Examples 6, 7 and 8. Further, among the examples, it can be seen that the thermoplastic elastomer composition of Example 4 containing high-viscosity paraffin oil is excellent in heat-sealing property with polyacetal.

The thermoplastic elastomer composition of the present invention is useful for various molded products such as automobile parts, electrical / electronic equipment parts, medical tools, building materials / piping members, daily life / cosmetic products, and further, grips, tubes, packings, gaskets, etc. , Used for various members such as cushion bodies, films, and seats.

Claims (10)

A thermoplastic elastomer composition containing a controlled distribution type styrene-based block copolymer A and a (meth) acrylic-based block copolymer B in a mass ratio (A / B) of 30/70 to 90/10 . The controlled distribution type styrene-based block copolymer A has a hard segment and a soft segment, and the hard segment is a block unit (block unit S) which is a polymerization unit of the styrene-based monomer, and the soft. The segment is a copolymerization unit of a conjugated diene and a styrene-based monomer, and is a block unit (block unit B) having a controlled distribution structure, and the block unit B contains the conjugated diene unit as a main constituent unit. A region having two or more regions and one or more regions containing a styrene-based monomer unit as a main constituent unit, and both ends adjacent to the block unit S containing a conjugated diene unit as a main constituent unit. Thermoplastic elastomer composition . The first aspect of claim 1, wherein the plasticizer C is contained in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the total amount of the controlled distribution type styrene block copolymer A and the (meth) acrylic block copolymer B. Thermoplastic elastomer composition. The thermoplastic elastomer composition according to claim 2, wherein the plasticizer C is at least one selected from the group consisting of paraffin oil, naphthenic oil, and aromatic oil. The thermoplastic elastomer composition according to claim 2 or 3, wherein the kinematic viscosity of the plasticizer C at 40 ° C. is 50 to 400 mm ² / s. The thermoplastic elastomer composition according to any one of claims 1 to 4, wherein the controlled distribution type styrene block copolymer A has a weight average molecular weight of 100,000 to 500,000. The block copolymer according to any one of claims 1 to 5, wherein the (meth) acrylic block copolymer B is a block copolymer having two or more blocks constituting a hard segment and one or more blocks constituting a soft segment. Thermoplastic elastomer composition. The claim that the glass transition temperature of the block constituting the hard segment of the (meth) acrylic block copolymer B is 20 to 200 ° C, and the glass transition temperature of the block constituting the soft segment is -100 to 19 ° C. 6. The thermoplastic elastomer composition according to 6. The thermoplastic elastomer composition according to any one of claims 1 to 7, wherein the (meth) acrylic block copolymer B has a weight average molecular weight of 20,000 to 500,000. The thermoplastic elastomer composition according to any one of claims 1 to 8, which is used for heat-sealing with polyacetal. A composite molded body in which the thermoplastic elastomer composition according to any one of claims 1 to 9 and polyacetal are heat-sealed.