JP2021011552A - Composite molding - Google Patents

Abstract

To provide a composite molding formed by fusing of an elastomer composition having excellent gas barrier properties and flexibility and a polyethylene resin being a hard resin.SOLUTION: The present invention provides a composite molding of an elastomer composition X containing an isobutylene block copolymer A composed of an isobutylene polymer block and an aromatic vinyl polymer block and a middle to low pressure polyethylene resin B of 5-300 pts.mass relative to the isobutylene block copolymer A 100 pts.mass, and a middle to low pressure polyethylene resin Y.SELECTED DRAWING: None

Description

The present invention relates to a composite molded product of an elastomer composition and a polyethylene resin.

Conventionally, composite molding (for example, two-color molding or insert molding) of different resins has been performed. For example, for automobile parts, automobile window frames and lamp packing, for building material parts, sash frames, and for light electric products, telephones. , Radios, TV remote controls, push buttons such as remote control keys for automobiles, toothbrushes, pen grips, and the like are subjected to such composite molding. When a plurality of resins to be composite-molded contain an elastomer and a hard resin, for example, if the housing in which the push button portion is removed as a window is made of the hard resin and the window portion is formed of the push button switch cover body using the elastomer. This combination is useful because it is possible to inexpensively manufacture a lightweight and highly waterproof remote control housing, and not only remote controls but also internal devices can be operated by external force while isolating the internal environment from the external environment. It can be used for various purposes such as tactile sensation and display of pressure difference.

Patent Document 1 discloses a push button switch cover that heat-seals various rigid thermoplastic resins from ABS resin to polypropylene resin and various thermoplastic elastomers.

On the other hand, polyethylene resin has long been known as a lightweight, inexpensive, and chemically stable material, and has a wide range of materials such as containers for chemicals and fuels, liquid transport pipes, food containers and packaging materials, mechanical parts, and building materials. Although it is commonly used as a material for applications, polyethylene resin is known as a poorly adhesive resin, while it has significantly better weather resistance than polypropylene resin, which is the same polyolefin resin, and is used as a composite molded product. Little known.

Conventionally, a thermoplastic elastomer composition has a lower gas barrier property than a hard resin, and when used as a composite molded body with a hard resin, the overall gas permeability is determined solely by the area of the window portion made of the thermoplastic elastomer composition. The idea is general.

Patent Document 2 describes a thermoplastic elastomer containing an isobutylene block copolymer composed of an isobutylene compound block and an aromatic vinyl compound block and an olefin block copolymer as an elastomer material having both gas barrier properties and flexibility. The composition is disclosed.

Japanese Unexamined Patent Publication No. 7-314580 Japanese Unexamined Patent Publication No. 2012-172136

When a medium- or low-pressure polyethylene resin is used as the hard resin constituting the composite molded product, the gas permeability of the hard resin and the thermoplastic elastomer composition should be made to the same level by selecting the composition of the thermoplastic elastomer composition. The degree of freedom in designing the window part can be increased. The gas barrier property of the material differs depending on the gas type, and it is natural that the oxygen permeability that causes oxidative deterioration is water vapor permeability, and if the water vapor permeability is high, the electronic circuit inside the housing is likely to be a problem. A combination of a hard resin and a thermoplastic elastomer that has as low a water vapor permeability as possible and has the same water vapor permeability because chemical reactions such as corrosion of food, mold of food, and hydrolysis and condensation of materials are likely to occur. It is preferable to construct the molded body because the degree of freedom in design is high. In addition to the flat surface, the flexible window portion may be configured in any shape such as a glove type, a toggle switch cover, a keyboard cover, etc. It is possible to manufacture the production line of.

Patent Document 1 suggests that the styrene-based thermoplastic elastomer and the polyolefin-based elastomer have good heat-sealing properties with a polyolefin-based resin such as PP resin. Is not described, and gas barrier properties have not been examined.

Further improvement in gas barrier property is also required for the thermoplastic elastomer composition described in Patent Document 2.

An object of the present invention is to provide a composite molded body in which an elastomer composition having excellent gas barrier properties and flexibility and a polyethylene resin as a hard resin are fused.

The present invention
[1] Isobutylene-based block copolymer A composed of an isobutylene-based polymer block and an aromatic vinyl-based polymer block, and 5 to 300 parts by mass with respect to 100 parts by mass of the isobutylene-based block copolymer A. A composite molded body of an elastomer composition X containing a medium / low pressure polyethylene resin B and a medium / low pressure polyethylene resin Y.
[2] The composite molded product according to [1] above, wherein the medium / low pressure polyethylene resin B is at least one of a high-density polyethylene resin and a linear low-density polyethylene resin.
[3] In the elastomer composition X, the rubber softening agent C is further added, and the total of the medium- and low-pressure polyethylene resin B and the rubber softening agent C is 6 to 100 parts by mass of the isobutylene block copolymer A. The composite molded product according to the above [1] or [2], which is contained so as to be 300 parts by mass.
[4] The above-mentioned [1] to [3], wherein the elastomer composition X further contains a hydrogenated block copolymer D having a crystalline ethylene block and an amorphous ethylene / α-olefin block. Composite molded body,
[5] The moisture permeability at 40 ° C. as measured by JIS K 0208 (cup method) of the elastomer composition X is less than 2.0g / m ² · 24h, molded composite according to any one above [1] to [4] The composite molded product according to any one of [1] to [5] above, wherein the body and [6] the medium / low pressure polyethylene resin Y are high density polyethylene resins.

In the composite molded product of the present invention, an elastomer composition having excellent gas barrier properties and flexibility is strongly heat-sealed with a polyethylene resin which is a hard resin.

The composite molded product of the present invention contains an elastomer composition X containing an isobutylene-based block copolymer composed of an isobutylene-based polymer block and an aromatic vinyl-based polymer block, and a medium- and low-pressure polyethylene resin B. The elastomer composition X, which is composed of the low-pressure polyethylene resin Y and is a combination of the isobutylene-based block copolymer A and the medium- and low-pressure polyethylene resin B, has good flexibility and an elastomer composition. Both the product X and the medium- and low-pressure polyethylene resin Y have excellent gas barrier properties, and the fusion property between the two is also good.

The isobutylene polymer block is a block containing a structural unit derived from an isobutylene compound (hereinafter, also referred to as an isobutylene compound unit).

The content of the isobutylene compound unit in all the structural units constituting the isobutylene polymer block is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably, from the viewpoint of water vapor barrier property at high temperature. Is 70% by mass or more.

The isobutylene-based polymer block may contain a structural unit derived from a monomer other than isobutylene as long as the effects of the present invention are not impaired. Examples of other monomers include aliphatic olefins, alicyclic olefins, aromatic vinyls, dienes, vinyl ethers, silanes, vinylcarbazoles, β-pinenes, acenaftylene and the like.

The content of the isobutylene-based polymer block is preferably 50 to 90% by mass, more preferably 55 to 85% by mass, and further preferably 60 to 80% by mass in the isobutylene-based block copolymer A.

The aromatic vinyl-based polymer block contains a structural unit derived from the aromatic vinyl-based compound (hereinafter, also referred to as an aromatic vinyl-based compound unit). Examples of the aromatic vinyl compound include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, vinylnaphthalene and the like, and two or more of them. May be used in combination. Of these, styrene, which is easily available, is preferable.

The content of the aromatic vinyl compound unit in all the structural units constituting the aromatic vinyl polymer block is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more. is there.

The aromatic vinyl polymer block may contain a structural unit derived from a monomer other than the aromatic vinyl compound as long as the effects of the present invention are not impaired. Examples of other monomers include copolymerizable monomers such as 1-butene, pentene, hexene, butadiene, isoprene, and methyl vinyl ether, which can be ion-polymerized.

The content of the aromatic vinyl-based polymer block is preferably 10 to 60% by mass, more preferably 15 to 50% by mass, and further preferably 20 to 40% by mass in the isobutylene-based block copolymer A.

The weight average molecular weight of the isobutylene block copolymer A is preferably 10,000 or more from the viewpoint of gas barrier properties, and preferably 300,000 or less from the viewpoint of flexibility and moldability. From these viewpoints, the weight average molecular weight of the isobutylene block copolymer A is preferably 10,000 to 300,000, more preferably 20,000 to 200,000, and further preferably 30,000 to 100,000.

The A hardness of the isobutylene block copolymer A is preferably 10 to 50, more preferably 15 to 45, and even more preferably 20 to 40.

The density of the isobutylene-based block copolymer A is preferably 0.92 to 0.97 g / cm ³ , more preferably 0.93 to 0.96 g / cm ³ , and even more preferably 0.94 to 0.95 g / cm ³ .

The content of the isobutylene-based block copolymer A is preferably 25 to 95% by mass, more preferably 25 to 90% by mass, and further preferably 50 to 85% by mass in the elastomer composition X.

Polyethylene resin can be roughly divided into medium- and low-pressure polyethylene resin and high-pressure polyethylene resin depending on the manufacturing method. High-density polyethylene resin (HDPE), which is linear by the medium- and low-pressure method, is longer by the high-pressure method. A low density polyethylene resin (LDPE) with chain branching is obtained. High-density polyethylene resin has high gas barrier property, and low-density polyethylene resin has low gas barrier property. Further, in recent years, a linear low density polyethylene resin (L-LDPE) is also known as a third polyethylene resin produced by the medium pressure method, and its gas barrier property is higher than that of the high pressure method polyethylene resin. Therefore, as the medium- or low-pressure polyethylene resin in the present invention, at least one of a high-density polyethylene resin and a linear low-density polyethylene resin is preferable, and a high-density polyethylene resin is more preferable.

The high-density polyethylene resin is a method of polymerizing ethylene at a temperature of 50 to 250 ° C. and 50 to 200 atm using a Ziegler catalyst (titanium type) in the low pressure method and a Phillips catalyst (chromium type) in the medium pressure method. Manufactured in.

The density of the high-density polyethylene resin is preferably 0.942 g / cm ³ or more, and more preferably 0.945 to 0.970 g / cm ³ .

The density of the linear low-density polyethylene resin is preferably 0.915 to 0.935 g / cm ³ , more preferably 0.918 to 0.930 g / cm ³ .

High-density polyethylene resin (HDPE) and low-density polyethylene resin (LDPE) are homopolyethylene polymers, whereas linear low-density polyethylene resin (L-LDPE) is a copolymer of ethylene and α-olefin. Is. Examples of such α-olefins include propylene, 1-butene, 2-butene, 1-pentene, 1-hexene, 3-methylpentene, 4-methylpentene, 1-octene, decene, 4-methylpentene-1 and the like. Be done.

The content of the structural unit derived from the α-olefin in all the structural units constituting the linear low-density polyethylene resin is preferably 4 to 17% by mass, more preferably 5 to 15% by mass.

The linear low-density polyethylene resin is produced by copolymerizing ethylene and α-olefin using a Phillips-type catalyst used in the medium-pressure method, and is a copolymerization component of a conventional high-density polyethylene resin. The short-chain branching structure was formed, and the density was appropriately reduced by utilizing this short-chain branching.
Therefore, the linear low-density polyethylene resin is a polyethylene resin having a structure that is more linear than the low-density polyethylene resin (LDPE) produced by the conventional high-pressure method and has more branches than the high-density polyethylene resin. For the linear low-density polyethylene resin, a manufacturing process of a gas phase polymerization method using a fluidized bed reactor, a stirring bed reactor, a tubular reactor, etc. is applied, and for example, Japanese Patent Application Laid-Open No. 54-148903 and 54- It can be produced based on the method described in No. 154488 or the like (gas phase polymerization method using a fluidized bed reactor).

The melt mass flow rate (MFR) of the medium / low pressure polyethylene resin B is 230 ° C. and a load of 21.2 N, preferably 0.5 to 50 g / 10 min, more preferably 1 to 20 g / 10 min, and further preferably 1.5 to 15 g / 10 min. is there.

Moisture permeability of medium and low-pressure polyethylene resin B is preferably less than 2.0 g / m ² · 24h, more preferably 1.8 g / m less than ² · 24h, more preferably 1.6 g / m less than ² · 24h, more preferably is less than 1.0g / m ² · 24h. Here, the moisture permeability is the moisture permeability at 40 ° C. measured by JIS K 0208 (cup method).

The oxygen permeability coefficient of the medium / low pressure polyethylene resin B is preferably less than 1.0 × 10 ^-15 mol ・ m / Pa ・ s ・ m ² , more preferably 0.8 × 10 ^-15 mol ・ m / Pa ・ s ・ m ^2. Less than, more preferably less than 0.6 × 10 ^-15 mol · m / Pa · s · m ² . Here, the oxygen permeability is a value measured by a method conforming to JIS K 7126.

The content of the medium- and low-pressure polyethylene resin B is 5 parts by mass or more from the viewpoint of moldability and fusion property with respect to 100 parts by mass of the isobutylene block copolymer A, and 300 parts by mass from the viewpoint of flexibility. It is less than a part by mass. From these viewpoints, the content of the medium- and low-pressure polyethylene resin B is 5 to 300 parts by mass, preferably 7 to 150 parts by mass, and more preferably 7 to 150 parts by mass with respect to 100 parts by mass of the isobutylene block copolymer A. It is 10 to 50 parts by mass, more preferably 20 to 30 parts by mass.

The content of the medium- and low-pressure polyethylene resin B in the elastomer composition X is preferably 5 to 75% by mass, more preferably 5 to 70% by mass, and further preferably 10 to 40% by mass.

From the viewpoint of flexibility, the elastomer composition X preferably further contains a softening agent C for rubber. Examples of the softening agent C for rubber include mineral oils such as paraffin oil, naphthenic oil and aromatic oil, and synthetic softeners such as polyolefin oils such as polyα-olefin and polybutene. Among these, a steam barrier From the viewpoint of properties, polyolefin oil is preferable, and polybutene oil is more preferable.

The kinematic viscosity of the rubber softener C at 40 ° C. is preferably 3,000 to 20,000 mm ² / s, more preferably 4,000 to 17,500 mm ² / s, still more preferably 5,000 to 5,000 to 2,000 to 20,000 mm ² / s, more preferably 4,000 to 17,500 mm ² / s, from the viewpoint of long-term heat resistance and gas barrier properties. It is 15,000 mm ² / s.

The number average molecular weight of the softening agent C for rubber is preferably 600 to 2000, more preferably 800 to 1500, and further preferably 900 to 1200 from the viewpoint of long-term heat resistance and gas barrier properties.

The content of the softening agent C for rubber is such that the total of the medium / low pressure polyethylene resin B and the softening agent C for rubber is preferably 6 to 300 parts by mass with respect to 100 parts by mass of the isobutylene block copolymer A. The amount is preferably 10 to 100 parts by mass.

The content of the softening agent C for rubber in the elastomer composition X is preferably 1 to 50% by mass, more preferably 5 to 30% by mass.

From the viewpoint of fusion to L-LDPE, the elastomer composition X may further contain a hydrogenated block copolymer D having a crystalline ethylene block and an amorphous ethylene / α-olefin block. preferable.

Examples of the α-olefin include butene, octene, hexene and the like. Of these, butene is preferable, and as the hydrogenated block copolymer D, a hydrogenated block copolymer (CEBC) having a crystalline ethylene block and an amorphous ethylene / butene block is preferable. In the present invention, the hydrogenated block copolymer D may be used alone or in combination of two or more.

Further, the hydrogenated block copolymer D may have a linear structure and a radial structure as a block bonding state. Examples of commercially available products having a linear structure include Dynaron 6101 and Dynaron 6200P (manufactured by JSR), and examples of commercially available products having a radial structure include Dynaron 6201B (manufactured by JSR). In the present invention, any structure can be preferably used, but in the case of the same weight average molecular weight, the radial structure is more preferable because the melt fluidity is higher.

The A hardness of the hydrogenated block copolymer D is preferably 40 or more from the viewpoint of compatibility between the isobutylene-based block copolymer A and the medium / low density polyethylene resin B, and 95 from the viewpoint of the flexibility of the composition. The following is preferred. From these viewpoints, the A hardness of the block copolymer D is preferably 40 to 95, more preferably 50 to 90, and even more preferably 60 to 80.

The content of the hydrogenated block copolymer D is 1 mass with respect to 100 parts by mass of the isobutylene block copolymer A from the viewpoint of compatibility between the isobutylene block copolymer A and the medium / low density polyethylene resin B. The amount is preferably 50 parts or more, and 50 parts by mass or less is preferable from the viewpoint of water vapor permeability. From these viewpoints, the content of the hydrogenated block copolymer D is preferably 1 to 50 parts by mass, more preferably 2 to 30 parts by mass, still more preferably, with respect to 100 parts by mass of the isobutylene-based block copolymer A. Is 5 to 20 parts by mass.

The content of the hydrogenated block copolymer D in the elastomer composition X is preferably 2 to 30% by mass, more preferably 5 to 20% by mass.

The composition of the present invention preferably contains an inorganic filler E from the viewpoint of water vapor barrier properties.

Inorganic filler E includes talc, mica, calcium carbonate, clay, titanium oxide, magnesium carbonate, barium sulfate, calcium sulfate, calcium sulfite, calcium phosphate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, magnesium oxide, iron oxide. , Zinc oxide, alumina, silica, diatomaceous soil, dolomite, gypsum, calcined clay, asbestos, calcium silicate, bentonite, white carbon, carbon black, iron powder, aluminum powder, stone powder, blast furnace slag, fly ash, cement, zirconia powder, etc. Among these, talc is preferable from the viewpoint of water vapor barrier property and dispersibility.

Various shapes such as granular, plate-shaped, rod-shaped, fibrous, and whisker-shaped are known as the inorganic filler, but in the present invention, the plate-shaped filler is used from the viewpoint of water vapor barrier property and gas barrier property. preferable. The plate shape means a shape in which the ratio of major axis to thickness (major axis / thickness) is 5 or more, preferably 10 to 500.

The volume-based median diameter of the inorganic filler E is preferably 1.5 μm or more from the viewpoint of dispersibility, and is preferably 150 μm or less from the viewpoint of flexibility. From these viewpoints, the volume-based median diameter of the plate-shaped inorganic filler is preferably 1.5 to 150 μm, more preferably 1.75 to 120 μm, and further preferably 2.0 to 15 μm.

The content of the inorganic filler E is preferably 1 part by mass or more from the viewpoint of water vapor barrier property, and 500 parts by mass or less from the viewpoint of the surface property of the molded product, with respect to 100 parts by mass of the isobutylene block copolymer A. preferable. From these viewpoints, the content of the inorganic filler E is preferably 1 to 500 parts by mass, more preferably 20 to 400 parts by mass, and further preferably 50 to 350 parts by mass with respect to 100 parts by mass of the isobutylene block copolymer A. It is a mass part.
When the inorganic filler E is plate-shaped, it is preferably 250 parts by mass or less, more preferably 200 parts by mass or less, from the viewpoint of water vapor barrier property and tube smoothness. Therefore, the content of the plate-shaped inorganic filler E is preferably 1 to 250 parts by mass, more preferably 20 to 200 parts by mass, and further preferably 30 to 150 parts by mass with respect to 100 parts by mass of the isobutylene block copolymer A. It is a mass part.

The content of the inorganic filler E in the elastomer composition X is preferably 1 to 50% by mass, more preferably 5 to 35% by mass.

The elastomer composition X in the present invention is, if necessary, a reinforcing agent for carbon black, silica, carbon fibers, glass fibers, etc., as long as the effects of the present invention are not impaired; an insulating heat conductive filler, a pigment, and a flame retardant. , Antistatic agent, mold release agent, tackifier, cross-linking agent, cross-linking aid, foaming agent, fragrance and other various additives may be contained.

Further, the elastomer composition X in the present invention may contain another thermoplastic resin or thermoplastic elastomer as long as the effects of the present invention are not impaired.

The elastomer composition X in the present invention includes isobutylene-based block copolymer A, medium- and low-pressure polyethylene resin B, and if necessary, rubber softener C, hydrogenated block copolymer D, inorganic filler E, and the like. It is obtained by appropriately mixing additives and solidifying them.

The term "mixing" as used in the present invention is not particularly limited as long as it is a method in which various raw materials are mixed well, and various raw materials may be dissolved in a soluble organic solvent and mixed, or by melt kneading. Although they may be mixed, it is preferable to mix the raw materials under the condition that the raw materials are melted.

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 using a mixing device such as a Henschel mixer in advance may be supplied from one hopper, or each component is charged into two hoppers and quantified with a screw or the like under the hopper. You may serve while.

The product obtained by mixing the raw materials constituting the elastomer composition X can be in the form of pellets, powders, 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 mold-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.

From the viewpoint of flexibility, the A hardness of the elastomer composition X is preferably 30 to 80, more preferably 50 to 75, and even more preferably 60 to 70.

The melt mass flow rate (MFR) of the elastomer composition X is 190 ° C. and a load of 21.2 N, preferably 0.1 g / 10 min or more, more preferably 1.0 to 15.0 g / 10 min, still more preferably 1.0 to 10.0 g / 10 min, and further. It is preferably 2.0 to 4.0 g / 10 min or more.

Moisture permeability of the elastomer composition X is preferably 2.0 g / m less than ² · 24h, more preferably less than 1.8g / m ² · 24h, more preferably less than 1.6g / m ² · 24h. Here, the moisture permeability is the moisture permeability at 40 ° C. measured by JIS K 0208 (cup method).

As the oxygen permeability of the elastomer composition X, the oxygen permeability coefficient is preferably less than 1.0 × 10 ^-15 mol ・ m / Pa ・ s ・ m ² , more preferably 0.8 × 10 ^-15 mol ・ m / Pa ・ s ・. Less than m ² , more preferably less than 0.6 × 10 ^-15 mol · m / Pa · s · m ² . Here, the oxygen permeability is a value measured by a method conforming to JIS K 7126.

Using the elastomer composition X and the medium / low pressure polyethylene resin Y, the composite molded product of the present invention in which both are fused is produced. The medium / low pressure method polyethylene resin Y is the same as the medium / low pressure method polyethylene resin B, and the medium / low pressure method polyethylene resin Y is preferably a high density polyethylene resin.

As the apparatus used for manufacturing the composite molded product, any molding machine capable of melting the molding material can be used. For example, a kneader, 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.

In the present invention, fusion refers to a phenomenon in which heat above the melting point of the elastomer composition X is applied to form a melt, which is then solidified at a temperature below the melting point to adhere to the interface to be fused. To apply heat, a hot press machine, a heating roll machine, a hot air generator, heated steam, an ultrasonic welder, a high frequency welder, a laser, or the like can be used. Therefore, 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.

Therefore, the elastomer composition X can be integrally formed with the medium- and low-pressure polyethylene resin Y to form a composite molded product. This makes it possible to combine members having complicated joint surfaces and members having joint surfaces having different shapes from each other.

The composite molded body of the present invention can be obtained by a method such as injection molding, injection compression molding, insert molding, multicolor molding, vacuum molding, pressure molding, blow molding, hot press molding, foam molding, laser fusion molding, extrusion molding, etc. It can be obtained by molding,

The composite molded product of the present invention includes an insert molded product in which the elastomer composition X is inserted into a molded product made of medium / low pressure polyethylene resin Y, and a medium / low pressure polyethylene resin Y in a molded product made of elastomer composition X. Examples thereof include an inserted insert molded product, a composite molded product obtained by multicolor molding the elastomer composition X and the medium / low pressure polyethylene resin Y.

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: Isobutylene-based block copolymer, etc.>
[Composition of block copolymer]
Proton NMR measurement is performed by a nuclear magnetic resonance apparatus (DPX-400 manufactured by BRUKER, Germany), and the content of styrene and / or styrene derivative, that is, an aromatic vinyl polymer, is determined by quantifying the characteristic group of styrene. Determine the block content. The content of other monomer units can also be determined by proton NMR measurement.

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

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

[A hardness]
Measure A hardness (value 1 second after the start of the test) with a measurement time of 1 second in accordance with JIS K 6253 for a stack of 3 plate-shaped injection molded samples with a thickness of 2 mm (total 6 mm). .. The measurement is carried out after adjusting the condition for one day in a room with a temperature of 23 ° C and a humidity of 50%.

〔density〕
Using the precision electronic hydrometer "SD-200L" manufactured by Alpha Mirage, the mass is measured in the atmosphere and in ethanol, and the density is calculated.

<Component B: Polyethylene resin, etc.>
〔density〕
Using the precision electronic hydrometer "SD-200L" manufactured by Alpha Mirage, the mass is measured in the atmosphere and in ethanol, and the density is calculated.

[Melt Mass Flow Rate (MFR)]
Measured in accordance with ASTM D1238 under the conditions of 230 ° C and a load of 21.2 N.

[Humidity permeability]
Measured in accordance with JIS K 0208 (cup method) using a moisture permeable cup (diameter 70 mm) manufactured by Yasuda Seiki Seisakusho under conditions: 40 ° C x 90% RH and sheet thickness: 0.5 mm.

[Oxygen permeability coefficient]
Measure at 23 ° C using the gas transmittance measuring device "BR-3" manufactured by Toyo Seiki Seisakusho Co., Ltd. by a method conforming to JIS K 7126. The test piece used is 90 mm x 90 mm x 0.5 mm t and has a transmission area of 38.5 cm ² .

<Component C: Softener for rubber>
[Kinematic viscosity]
Measure at a temperature of 40 ° C according to JIS Z 8803.

[Number average molecular weight]
The number average molecular weight is determined in terms of polystyrene by the same method as for component A.

<Component D: Block copolymer having a crystalline ethylene block and an amorphous ethylene / α-olefin block>
[A hardness]
Measure A hardness (value 1 second after the start of the test) with a measurement time of 1 second in accordance with JIS K 6253 for a stack of 3 plate-shaped injection molded samples with a thickness of 2 mm (total 6 mm). .. The measurement is carried out after adjusting the condition for one day in a room with a temperature of 23 ° C and a humidity of 50%.

〔density〕
Using the precision electronic hydrometer "SD-200L" manufactured by Alpha Mirage, the mass is measured in the atmosphere and in ethanol, and the density is calculated.

<Component E: Inorganic filler>
[Volume-based median diameter]
According to the laser diffraction / scattering method specified in JIS M8511, 0.1 g of the sample was dispersed in 10 mL of deionized water, and the slurry dispersed with 70 w ultrasonic waves for 30 seconds was particle-sized with "Mastersizer 2000" manufactured by Malvern. The distribution is measured, and the 50% value in the volume-based integrated fraction is taken as the volume-based median diameter.

Examples 1-7 and Comparative Examples 1-5
(1) Preparation of Elastomer Composition (Pellet) The raw materials shown in Tables 4 and 5 other than the softener (component C) were dry-blended and then impregnated with the softener to prepare a mixture. Then, the mixture was melt-kneaded with an extruder under the following conditions, extruded into strands, and cut to a diameter of about 3 mm and a thickness of about 3 mm with a cutter while being cooled in cold water to produce pellets of an elastomer composition. ..

[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 4 and 5 used in Examples and Comparative Examples are as follows.

(2) Preparation of Molded Body of Thermoplastic Elastomer Composition Pellets were 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 molding conditions]
Injection molding machine: 100MSIII-10E (trade name, manufactured by Mitsubishi Heavy Industries, Ltd.)
Injection molding temperature: 200 ° C
Injection pressure: 30%
Injection time: 3 sec
Mold temperature: 40 ℃

(3) Preparation of composite molded product As a polyolefin resin
HDPE (Nipolon Hard 4020 manufactured by Tosoh) and L-LDPE (Evolu SP2520 manufactured by Prime Polymer Co., Ltd.)
Pellets are injection molded under the following conditions to prepare a resin plate with a thickness of 2 mm, a width of 125 mm, and a length of 125 mm, which is cut with a cutting machine and fused to a thickness of 2 mm, a width of 25 mm, and a length of 125 mm. A test substrate was obtained.

[Polyolefin plate molding conditions]
Gate: Film Gate Cylinder temperature: 200 ℃
Weighing value: 55mm
Holding pressure switching position: 3.8 mm

The prepared polyolefin plate was inserted into a mold having a thickness of 4 mm, a width of 25 mm, and a length of 125 mm, and the elastomer compositions obtained in Examples and Comparative Examples were injection-molded to prepare a strip-shaped composite molded body.

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

The elastomer compositions and composite molded products obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in Tables 4 and 5.

[A hardness of elastomer composition]
Three 2 mm thick plate-shaped injection molded samples (6 mm in total) are stacked in a room with a temperature of 23 ° C and humidity of 50% for one day, and then JIS K 6253-3 Type A is used. The A hardness (value 1 second after the start of the test) with a measurement time of 1 second was measured.

[MFR of elastomer composition]
Measured according to ASTM D1238 under the conditions of 190 ° C and a load of 21.2N.

[Humidity permeability of elastomer composition]
The elastomer composition was placed in a press mold having a thickness of 0.5 mm, a width of 100 mm, and a length of 120 mm, and was heated to 160 ° C. using a heat press machine (Toho Machinery Co., Ltd., hydraulic molding machine TB-50-2 type). A heat press for 2 minutes and then a cooling press for 3 minutes were carried out to prepare a sheet-shaped press-molded product having a thickness of 0.5 mm as a test piece.
Measured in accordance with JIS K 0208 (cup method) using a moisture permeable cup (diameter 70 mm) manufactured by Yasuda Seiki Seisakusho under the conditions: 40 ° C x 90% RH and sheet thickness: 0.5 mm.

[Oxygen permeability coefficient of elastomer composition]
The elastomer composition was placed in a press mold having a thickness of 0.5 mm, a width of 100 mm, and a length of 120 mm, and was heated to 160 ° C. using a heat press machine (Toho Machinery Co., Ltd., hydraulic molding machine TB-50-2 type). A heat press for 2 minutes and then a cooling press for 3 minutes were carried out to prepare a sheet-shaped press-molded product having a thickness of 0.5 mm as a test piece. The test piece size was 90 mm x 90 mm x 0.5 mm t and the transmission area was 38.5 cm ² .
The measurement was performed at 23 ° C. using the gas permeability measuring device "BR-3" manufactured by Toyo Seiki Seisakusho Co., Ltd. by a method conforming to JIS K 7126.

[Fusionability of composite molded product]
Using a composite molded product, a tensile test was performed on the elastomer composition layer (skin material layer) and the polyolefin resin layer (base material layer) at an atmospheric temperature of 23 ° C at 50 mm / min in the 180 ° direction to obtain the skin material layer. The peel strength (unit: N / 25 mm) of the base material layer was measured. The peel strength is preferably 120 N / 25 mm or more.

From the above results, it can be seen that the composite molded products of Examples 1 to 7 are excellent in gas barrier property of the elastomer composition and that the fusion between the elastomer composition and the polyethylene resin is also strong.
On the other hand, in Comparative Examples 1 and 2 in which the elastomer composition does not contain the polyethylene resin, the moisture permeability is insufficient. In Comparative Example 3 in which the elastomer composition contained a low-density polyethylene resin which is a high-pressure polyethylene resin as the polyethylene resin, and Comparative Example 4 in which the polypropylene resin was contained instead of the polyethylene resin, the adhesiveness to the high-density polyethylene resin was insufficient. Is. Further, in Comparative Example 5 containing SEBS instead of the isobutylene block copolymer, the moisture permeability is insufficient.
Reference Example 1 is the result of measuring the physical characteristics of the component A "SIBSTAR 062T-UC" in the same manner as the elastomer compositions of Examples and Comparative Examples. The isobutylene block copolymer itself can be used in HDPE. Although it hardly fuses, it can be seen that the meltability to HDPE appears when it is mixed with a predetermined amount of medium / low pressure polyethylene resin.

The composite molded body of the present invention includes automobile window frames and lamp packings for automobile members, sash frames for building material members, telephones, radios, TV remote controls, automobile remote control keys and other push buttons, and toothbrushes for light electrical products. , Can be used for various molded products such as pen grips.

Claims (6)

Medium / low pressure of 5 to 300 parts by mass with respect to 100 parts by mass of isobutylene-based block copolymer A composed of isobutylene-based polymer block and aromatic vinyl-based polymer block and the isobutylene-based block copolymer A. A composite molded body of an elastomer composition X containing a polyethylene resin B and a medium / low pressure polyethylene resin Y. The composite molded product according to claim 1, wherein the medium / low pressure polyethylene resin B is at least one of a high-density polyethylene resin and a linear low-density polyethylene resin. In the elastomer composition X, the rubber softening agent C is further added to 100 parts by mass of the isobutylene block copolymer A, and the total of the medium- and low-pressure polyethylene resin B and the rubber softening agent C is 6 to 300 parts by mass. The composite molded product according to claim 1 or 2, which is contained so as to be. The composite molded product according to any one of claims 1 to 3, wherein the elastomer composition X further contains a hydrogenated block copolymer D having a crystalline ethylene block and an amorphous ethylene / α-olefin block. Moisture permeability at 40 ° C. as measured by JIS K 0208 of the elastomer composition X (cup method) is less than 2.0g / m ² · 24h, composite molding according to any one of claims 1 to 4. The composite molded product according to any one of claims 1 to 5, wherein the medium / low pressure polyethylene resin Y is a high density polyethylene resin.