JP2006194318A - Pipe made of polypropylene resin composition - Google Patents

Abstract

Provided is a polypropylene resin composition pipe having improved mechanical property balance and smoothness of the inner surface of a pipe, which has improved the drawbacks of conventional polypropylene pipes, and having a low linear expansion coefficient.
(A) 60 to 90 parts by weight of a polypropylene resin, (b) 10 to 50% by weight of a vinyl aromatic hydrocarbon, and 30 to 70% of a conjugated diene is a hydrogenated non-hydrogenated elastomer. It consists of 2 to 20 parts by weight of added hydrogenated elastomer and (c) 5 to 30 parts by weight of a plate-like filler having an average particle diameter of 0.5 to 10 μm, and has a linear expansion coefficient of 5 × 10 ^{−5 to} 12 × 10. ^A pipe made of a polypropylene resin composition in the range of ⁻⁵ / ° C. (However, component (a) + component (b) + component (c) = 100 wt%)
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Description

  The present invention relates to a pipe made of a polypropylene resin composition. More specifically, the present invention relates to a polypropylene resin composition pipe comprising a polypropylene resin, a specific hydrogenated elastomer, and a specific inorganic filler. Since the polypropylene resin composition of the present invention has an excellent balance of mechanical properties, has heat resistance, chemical resistance, and a low linear expansion coefficient, the pipe made of the resin composition is used for chemical plants, air conditioning, hot water supply applications, etc. It can be suitably used as a pipe.

Currently, vinyl chloride pipes are used in a wide range of applications. Vinyl chloride resin is highly evaluated for its convenience, such as the ability to adjust a wide range of pipe products from soft to hard by adjusting plasticizer, etc., and the ability to easily join pipes with adhesives. Since it contains a large amount of chlorine, there is a concern about environmental impact, and recently, an alternative material has been demanded.
In recent years, non-vinyl chloride resin-based pipe materials have been studied mainly in polyethylene resins (see, for example, Patent Document 1). On the other hand, polypropylene pipes are excellent in heat resistance and chemical resistance, and are expected to be used in various applications. However, one problem with polypropylene pipes is that they have a high coefficient of linear expansion against temperature changes, It has been pointed out that it is easy to sag.

  Polypropylene resins are used for automotive applications such as bumpers, but the high linear expansion of polypropylene molded products is also a problem in the automotive field, and various studies have been conducted. For example, a composition comprising polypropylene, ethylene-1-butene copolymer, ethylene-propylene copolymer, and talc is disclosed for the purpose of automobile bumper use (see, for example, Patent Documents 2 to 8). In the above technique, it is necessary to add a large amount of olefin-based elastomer in order to cover physical property deterioration due to the addition of talc, and sacrifices the surface properties, rigidity, and the like of the polypropylene resin. For the purpose of improving paintability, an attempt to add a highly fluid styrene elastomer to polypropylene and talc compositions has been disclosed (Patent Document 9). Patent documents 2 to 9 relate to a polypropylene resin composition for injection molding, and relate to a relatively high fluidity polypropylene resin composition. In the pipe application which is the object of the present invention, a pipe excellent in various physical property balances cannot be provided unless the elastomer and inorganic filler used are optimum.

Japanese Patent No. 3497284 Japanese Patent Laid-Open No. 50-51498 JP-A-5-86256 JP-A-5-98094 JP-A-6-32951 JP-A-6-256596 Japanese Patent Laid-Open No. 10-176084 JP 2002-97337 A JP, 5-105788, A As mentioned above, the polypropylene pipe which is excellent in mechanical properties, has the smoothness of the inner surface of a pipe, and a low linear expansion coefficient has not been completed yet.

  It is an object of the present invention to provide a polypropylene resin composition-made pipe that has a mechanical property balance that improves the drawbacks of conventional polypropylene pipes, is excellent in smoothness of the inner surface of the pipe, and has a low linear expansion coefficient.

As a result of various studies to solve the above problems, the present inventors have found that a polypropylene resin composition pipe comprising a polypropylene resin, a specific hydrogenated elastomer, and a specific inorganic filler is excellent in various properties. As a result, the present invention has been completed.
That is, the present invention
[1] (a) 60 to 90% by weight of polypropylene resin, (b) 10 to 50% by weight of vinyl aromatic hydrocarbon, and 30 to 70% of conjugated diene is hydrogenated with a non-hydrogenated elastomer It consists of 2 to 20% by weight of a hydrogenated elastomer and (c) 5 to 30% by weight of a plate-like filler having an average particle diameter of 0.5 to 10 μm, and a linear expansion coefficient of 5 × 10 ^{−5 to} 12 × 10 ⁻⁵ / ° C. Pipe made of polypropylene resin composition in the range of. (However, component (a) + component (b) + component (c) = 100 wt%)
[2] Hydrogenated elastomer having a melt flow rate of 0.1 to 20 g / 10 min at 230 ° C. and a load of 2.16 kg, and having a loss tangent (tan δ) peak of −32 ° C. or lower in the dynamic viscoelastic spectrum. The pipe made of a polypropylene resin composition according to [1], characterized in that it exists.
[3] A pipe made of a polypropylene resin composition according to [1] or [2], wherein the plate-like filler is talc and / or mica.

  A pipe made of a polypropylene resin composition of the present invention has a mechanical property balance, smoothness of the inner surface of the pipe, a low linear expansion coefficient, a chemical plant pipe that requires chemical resistance, heat resistance, etc., which are characteristics of polypropylene resin, Suitable for hot water supply pipes, air conditioning pipes and the like.

Hereinafter, the present invention will be described in detail.
Component (a) in the present invention is a polypropylene resin. The component (a) polypropylene resin in the present invention is a polypropylene resin having crystallinity, such as a crystalline propylene homopolymer, a crystalline ethylene-propylene copolymer, a crystalline propylene-α-olefin copolymer, and the like. These may be used alone or in combination of two or more. The α-olefin used in the crystalline propylene-α-olefin copolymer is an α-olefin having 4 or more carbon atoms, preferably an α-olefin having 4 to 20 carbon atoms, more preferably carbon. It is an α-olefin having a number of 4 to 12. For example, butene-1, pentene-1, hexene-1, heptene-1, octene-1, decene-1, etc. are mentioned. Examples of the crystalline propylene-α-olefin copolymer include a crystalline propylene-butene-1 copolymer and a crystalline propylene-hexene-1 copolymer. The component (a) polypropylene resin in the present invention is preferably a crystalline propylene homopolymer, a crystalline ethylene-propylene block copolymer, or a mixture thereof. The crystalline ethylene-propylene block copolymer in the present invention is a crystalline ethylene-propylene block copolymer comprising a propylene homopolymer portion and an ethylene-propylene random copolymer portion.

As a manufacturing method of the component (a) polypropylene resin in this invention, the method of manufacturing with a well-known polymerization method using a well-known stereoregular olefin polymerization catalyst is mentioned. Known catalysts include, for example, Ziegler-Natta catalyst systems, metallocene catalyst systems, catalyst systems combining them, etc., and known polymerization methods include, for example, bulk polymerization methods, solution polymerization methods, slurry polymerization methods Alternatively, a gas phase polymerization method or a polymerization method in which these polymerization methods are arbitrarily combined may be mentioned, and a continuous gas phase polymerization method is preferable.
The component (a) polypropylene resin in the present invention is 60 to 90% by weight, preferably 70 to 87% by weight, and more preferably 75 to 85% by weight in 100% by weight of the polypropylene resin composition. When the amount is less than 60% by weight, the proportion of the polypropylene resin is too small, the mechanical strength of the polypropylene resin composition pipe becomes insufficient, and the heat-melt fusion between pipes becomes poor. On the other hand, if it exceeds 90% by weight, the pipe has a high coefficient of linear expansion, which causes a problem that the pipe twists during long-term use. The melt flow rate of the component (a) polypropylene resin in the present invention is not particularly limited, but the melt flow rate under a load of 2.16 kg at 230 ° C. is in the range of 0.1 to 2.0 g / 10 min. This is preferable from the viewpoint of parison stability during pipe molding.

Next, the component (b) hydrogenated elastomer in the present invention will be described. The hydrogenated elastomer which is the component (b) in the present invention is a hydrogenated elastomer obtained by hydrogenating a non-hydrogenated elastomer comprising a vinyl aromatic hydrocarbon and a conjugated diene, and the vinyl aromatic hydrocarbon is 10 to 10%. This is a hydrogenated elastomer obtained by hydrogenating a non-hydrogenated elastomer in which 50% by weight and 30 to 70% of the conjugated diene is a vinyl bond.
Examples of the method for producing the non-hydrogenated elastomer include, for example, Japanese Patent Publication No. 36-19286, Japanese Patent Publication No. 43-17879, Japanese Patent Publication No. 46-32415, Japanese Patent Publication No. 49-36957, Japanese Patent Publication No. 48-2423. And the methods described in JP-B-48-4106, JP-B-56-28925, JP-B-51-49567, JP-A-59-166518, JP-A-60-186777, and the like. It is done. For example, it has a structure represented by the following general formula.
(A-B) _n , A- (B-A) _n , B- (A-B) _n
(In the above formula, A is a polymer block mainly composed of vinyl aromatic hydrocarbons, and B is a polymer mainly composed of conjugated dienes. The boundary between the A block and the B block is always clearly distinguished. (It is not necessary, and n is an integer of 1 or more, preferably an integer of 1 to 5.)

  In the above, the polymer block A mainly composed of vinyl aromatic hydrocarbon is preferably a vinyl aromatic hydrocarbon containing 50 wt% or more, more preferably 70 wt% or more of vinyl aromatic hydrocarbon and conjugated diene. A copolymer block and / or a vinyl aromatic hydrocarbon homopolymer block is shown, and the polymer block B mainly composed of conjugated diene preferably contains conjugated diene in an amount exceeding 50 wt%, more preferably 60 wt% or more. 2 shows a copolymer block of a conjugated diene and a vinyl aromatic hydrocarbon and / or a conjugated diene homopolymer block. The vinyl aromatic hydrocarbons in the copolymer block may be uniformly distributed or tapered. Further, in the copolymer part, a plurality of parts where the vinyl aromatic hydrocarbons are uniformly distributed and / or a part where the vinyl aromatic hydrocarbons are distributed in a tapered shape may coexist. The component (b) hydrogenated elastomer used in the present invention may be an arbitrary mixture of block copolymers represented by the above general formula. In the present invention, the microstructure of the conjugated diene moiety in the non-hydrogenated elastomer (ratio of cis, trans, vinyl) can be arbitrarily changed by using a polar compound or the like described later. What is the vinyl bond in the present invention? When 1,3-butadiene is used as the conjugated diene, 1,2-vinyl bond, isoprene is used, or 3,4-vinyl bond is shown.

  Examples of the vinyl aromatic hydrocarbon in the component (b) hydrogenated elastomer in the present invention include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methyl. There are styrene, vinyl naphthalene, vinyl anthracene, etc., and styrene is particularly common. These may be used alone or in combination of two or more in the production of one hydrogenated elastomer. As the conjugated diene, the conjugated diene is a diolefin having a pair of conjugated double bonds, such as 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl- 1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and the like, with 1,3-butadiene and isoprene being particularly common. These may be used alone or in combination of two or more in the production of one hydrogenated elastomer.

  The vinyl aromatic hydrocarbon content of the non-hydrogenated elastomer of the present invention is 10 to 50% by weight, preferably 11 to 40% by weight, and more preferably 12 to 35% by weight. When the amount is less than 10% by weight or exceeds 50% by weight, the linear expansion coefficient of the polypropylene resin composition pipe becomes high, and the physical properties of the polypropylene resin composition pipe greatly deteriorate due to the addition of talc. In the present invention, the vinyl bond of the conjugated diene of the non-hydrogenated elastomer is 30 to 70%. Preferably it is 30-60, More preferably, it is in the range of 30-50%. If it is less than 30%, an ethylene chain is formed in the hydrogenated elastomer, and as a result, the rubber component in the elastomer is crystallized, the physical properties of the polypropylene resin composition pipe are lowered, and the linear expansion coefficient is improved. Few. On the other hand, if it exceeds 70%, a large amount of ethyl side chains are inserted into the hydrogenated elastomer, and as a result, the compatibility with the component (a) polypropylene resin is improved too much, and the crystallinity of the polypropylene resin is lowered. Not only the physical properties of the polypropylene resin composition pipe are lowered, but also the linear expansion coefficient is high.

  The non-hydrogenated elastomer in the present invention is generally produced by anionic polymerization. In anionic polymerization, an organolithium compound is suitably used as a catalyst. The organic lithium compound is a compound in which one or more lithium atoms are bonded in the molecule, for example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, hexa Examples include methylene dilithium, butadienyl dilithium, and isoprenyl dilithium. These may be used alone or in combination of two or more. The organolithium compound may be added in one or more divided portions during the polymerization in the production of the non-hydrogenated elastomer. Solvents used for the production of non-hydrogenated elastomers include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane and isooctane, and fats such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane and ethylcyclohexane. Cyclic hydrocarbons or hydrocarbon solvents such as aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene can be used. These may be used alone or in combination of two or more.

  Polar compounds and randomizing agents are used to adjust the polymerization rate during production of non-hydrogenated elastomers, change the microstructure of polymerized conjugated diene moieties, and adjust the reactivity ratio of conjugated dienes and vinyl aromatic hydrocarbons. can do. Examples of polar compounds and randomizing agents include ethers, amines, thioethers, phosphoramides, potassium or sodium salts of alkylbenzene sulfonic acids, potassium or sodium alkoxides, and the like. Examples of suitable ethers are dimethyl ether, diethyl ether, diphenyl ether, tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether. As amines, tertiary amine, trimethylamine, triethylamine, tetramethylethylenediamine, and other cyclic tertiary amines can be used. Examples of phosphine and phosphoramide include triphenylphosphine and hexamethylphosphoramide.

  In the present invention, in order to saturate the double bond of the conjugated diene part, the non-hydrogenated elastomer needs to be hydrogenated and converted to the component (b) hydrogenated elastomer. The hydrogenation catalyst is not particularly limited and is conventionally known (1) A supported heterogeneous hydrogenation in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, diatomaceous earth, or the like. A catalyst, (2) a so-called Ziegler-type hydrogenation catalyst using an organic acid salt such as Ni, Co, Fe, Cr or a transition metal salt such as acetylacetone salt and a reducing agent such as organic aluminum, (3) Ti, Ru, A homogeneous hydrogenation catalyst such as a so-called organometallic complex such as an organometallic compound such as Rh or Zr is used. Specific examples of the hydrogenation catalyst include Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-337970, Japanese Patent Publication No. 1-53851, The hydrogenation catalyst described in Japanese Utility Model Publication No. 2-9041 can be used. A preferred hydrogenation catalyst is a mixture with a titanocene compound and / or a reducing organometallic compound.

As the titanocene compound, compounds described in JP-A-8-109219 can be used. Specific examples thereof include (substitution) such as biscyclopentadienyl titanium dichloride and monopentamethylcyclopentadienyl titanium trichloride. Examples thereof include compounds having at least one ligand having a cyclopentadienyl skeleton, an indenyl skeleton, or a fluorenyl skeleton. Examples of the reducing organometallic compound include organic alkali metal compounds such as organolithium, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds.
The hydrogenation reaction is preferably carried out in a temperature range of 0 to 200 ° C, more preferably 30 to 150 ° C. The pressure of hydrogen used for the hydrogenation reaction is preferably 0.1 to 15 MPa, more preferably 0.2 to 10 MPa, and still more preferably 0.3 to 5 MPa. The hydrogenation reaction time is preferably 3 minutes to 10 hours, more preferably 10 minutes to 5 hours. The hydrogenation reaction can be any of a batch process, a continuous process, or a combination thereof.

In the component (b) hydrogenated elastomer used in the present invention, the total hydrogenation rate of unsaturated double bonds based on the conjugated diene compound can be arbitrarily selected according to the purpose and is not particularly limited. 70% or more, preferably 80% or more, more preferably 90% or more of the unsaturated double bonds based on the conjugated diene compound in the hydrogenated elastomer may be hydrogenated, or only a part thereof is hydrogenated. May be. When only a part is hydrogenated, the hydrogenation rate is preferably 10% or more and less than 70%, or 15% or more and less than 65%, and if desired, 20% or more and less than 60%.
Furthermore, in the component (b) hydrogenated elastomer in the present invention, the hydrogenation rate of vinyl bonds based on the conjugated diene of the non-hydrogenated elastomer is preferably 85% or more, more preferably 90% or more, and still more preferably 95. % Or more is recommended for obtaining a polypropylene resin composition having excellent thermal stability. Here, the hydrogenation rate of vinyl bonds refers to the ratio of hydrogenated vinyl bonds among vinyl bonds based on the conjugated diene of the non-hydrogenated elastomer incorporated in the hydrogenated elastomer.

The hydrogenation rate of the aromatic double bond based on the vinyl aromatic hydrocarbon in the component (b) hydrogenated elastomer is not particularly limited, but is preferably 50% or less, more preferably 30% or less, still more preferably 20% or less is recommended. The hydrogenation rate can be known by a nuclear magnetic resonance apparatus (NMR).
The component (b) hydrogenated elastomer used in the present invention has a linear expansion coefficient, fluidity, and mechanical property balance that the melt flow rate at 230 ° C. and a load of 2.16 kg is 0.1 to 20 g / 10 min. This is more preferable. In addition, the hydrogenated elastomer preferably has a loss tangent (tan δ) peak of −32 ° C. or lower in the dynamic viscoelastic spectrum from the viewpoint of the impact resistance of the polypropylene resin composition pipe. The loss tangent (tan δ) peak in the dynamic viscoelastic spectrum is measured at a frequency of 10 Hz using a viscoelasticity analyzer.

The component (b) hydrogenated elastomer in the present invention may be used as a terminally modified product using a known extrusion graft method or a living terminal, but when a large amount of a modifying group is added, a polypropylene resin There exists a tendency for the linear expansion coefficient of a composition to fall.
The component (c) in the present invention is a plate-like filler having an average particle size of 0.5 μm to 10 μm. The plate-like filler is oriented in the flow direction of the molded product, and has the effect of reducing the linear expansion coefficient of the polypropylene resin composition pipe in the present invention and improving the rigidity. Examples of the plate-like filler include talc, mica, sericite, glass flake, synthetic mica, montmorillonite, graphite, plate-like calcium carbonate, plate-like alumina, and bainite. Since it acts also as an agent and has the effect | action which raises the crystallinity degree of polypropylene, it is preferable as a plate-shaped filler of this invention. Further, the plate-like filler in the present invention may be used as it is, or various known silane cups for the purpose of improving the interfacial adhesion with the component (a) polypropylene resin and improving the dispersibility. A ring agent, a titanium coupling agent, a higher fatty acid, a higher fatty acid ester, a higher fatty acid amide, a higher fatty acid salt, or other surfactants may be used.

The average particle diameter of the component (c) plate-like filler in the present invention is 0.5 μm to 10 μm, preferably 1 μm to 8 μm, more preferably 2 μm to 6 μm. If the thickness is less than 0.5 μm, it is difficult to pulverize the plate-like filler, and it is aggregated during handling, resulting in poor dispersion in the polypropylene resin composition and less effect of reducing the linear expansion coefficient. Since it also functions as a stress concentration point, mechanical properties deteriorate. When using plate-like fillers exceeding 10 μm, it is necessary to add a large amount of plate-like fillers in order to sufficiently reduce the linear expansion coefficient of the polypropylene resin composition. As a result, the mechanical properties are deteriorated, the roughness of the pipe surface is deteriorated, and the melt-fusion property of the pipe is also deteriorated. The average particle diameter means a 50% equivalent particle diameter D50 measured by a laser analysis method and obtained from an integral distribution curve.
The component (c) plate-like filler used in the present invention is 5 to 30% by weight, preferably 8 to 25% by weight, and more preferably 10 to 20% by weight with respect to 100% by weight of the polyprolene resin composition. If it is less than 5% by weight, the coefficient of linear expansion of the polypropylene resin composition pipe is high, and if it exceeds 30% by weight, the surface roughness of the polypropylene resin composition pipe and the mechanical properties are greatly reduced, and the pipe is melted by heat. Sex is reduced.

  The polypropylene resin composition in the present invention can be produced by using a kneader such as a single screw extruder, a twin screw extruder, a Banbury mixer, a hot roll or the like. The mixing of each component may be performed at the same time or may be performed separately. As a method of divided addition, (a) a polypropylene resin and (c) a plate-like filler are kneaded and then (b) a hydrogenated elastomer is added, or (a) a plate-like filler is added to a polypropylene resin in advance. There is a method of kneading to a concentration to obtain a master batch, and separately kneading the mixture with (a) polypropylene or (b) hydrogenated elastomer. Furthermore, as a second method of divided addition, (a) a polypropylene resin and (b) a hydrogenated elastomer are kneaded and then (c) a plate-like filler is added and kneaded. b) There is a method in which a hydrogenated elastomer is kneaded at a high concentration to obtain a master batch, and (a) polypropylene and (c) a plate-like filler are added thereto and kneaded. As a third method of divided addition, (a) polypropylene resin and (c) plate-like filler, (a) polypropylene resin and (b) hydrogenated elastomer are kneaded, and finally they are combined to other components. And kneading together. The temperature required for kneading is preferably set in the range of 160 to 250 ° C.

  In the present invention, in addition to the basic components, antioxidants, ultraviolet absorbers, lubricants, pigments, antistatic agents, copper damage inhibitors, flame retardants, neutralizers, foaming agents, plasticizers, nucleating agents, and bubble prevention agents An additive such as a crosslinking agent can be blended. In order to improve outdoor weather resistance, heat resistance, and oxidation stability, it is preferable to add an antioxidant or an ultraviolet absorber. Antioxidants include 2,6-ditert-butylphenol, 2,6-ditert-butyl-4-ethylphenol, 2,6-ditert-butyl-α-dimethylamino-bara-cresol, 6- (4 -Hydroxy-3,5-ditert-butylanilino) -2,4-bisoctyl-thio-1,3,5-triazine, 2,6-ditert-butyl-4-methylphenol, tris- (2-methyl- 4-hydroxy-5-tert-butylphenyl) butane, tetrakis- [methylene-3- (3 ′, 5′-ditert-butyl-4′-hydroxyphenyl) propionate] methane, diteurylthiodipropionate, etc. UV absorbers include 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-octadecyloxybenzophenone, 4-dodecyloxy-2-hydroxy Benzophenone, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-ditert-butyl-phenyl) ) -5-chlorobenzotriazole, bis- (2,6-dimethyl-4-piperidyl) sebacate and the like.

  In addition, a known resin and rubber / elastomer may be added to the polypropylene resin composition used in the present invention as long as the object of the present invention is not impaired. For example, a rubber-modified styrene resin (HIPS), polyethylene, a copolymer of ethylene containing 50 wt% or more of ethylene and another monomer copolymerizable therewith, for example, ethylene-propylene copolymer, ethylene-butylene copolymer Polymer, ethylene-hexene copolymer, ethylene-octene copolymer, polyethylene resin such as chlorinated polyethylene, polypropylene resin such as chlorinated polypropylene, polybutene-1, butene containing 50 wt% or more of butene-1 A polymer having a structure in which a part or all of hydrogen in a chain hydrocarbon polymer compound is substituted with fluorine is a polybutene resin which is a copolymer of 1 and another monomer copolymerizable therewith .

  Specifically, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polychlorotrifluoroethylene, tetrafluoroethylene-ethylene copolymer, chlorotrifluoro Fluorine resins such as ethylene-ethylene copolymers, polyvinylidene fluoride and polyvinyl fluoride, polybutadiene resins such as 1,2-polybutadiene and transpolybutadiene, and rubbery polymers include butadiene rubber and hydrogenated products thereof ( However, it is different from the hydrogenated polymer of the present invention), isoprene rubber, acrylonitrile-butadiene rubber and its hydrogenated product, chloroprene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, Tylene-butene-diene rubber, butyl rubber, ethylene-butene rubber, ethylene-hexene rubber, ethylene-octene rubber, acrylic rubber, fluorine rubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α, β-unsaturated nitrile-acrylate ester-conjugated Examples include diene copolymer rubber, urethane rubber, polysulfide rubber, and natural rubber. These rubber-like polymers may be modified products provided with functional groups. These rubbery polymers may be used in combination of two or more.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. In the following examples and comparative examples, physical properties and the like were measured as follows.
The following items were measured for hydrogenated elastomer.
(1) Styrene content It computed from the absorption intensity of 262 nm using the ultraviolet spectrophotometer (Hitachi UV200).
(2) Vinyl bond amount It measured using the nuclear magnetic resonance apparatus (The product made by BRUKER, DPX-400).
(3) Melt flow rate MFR
Based on JISK-7210, it measured at the temperature of 230 degreeC with a 2.16kg load.
(4) Peak temperature of loss tangent (tan δ) It was determined by measuring a viscoelastic spectrum using a viscoelasticity measurement analyzer (model DVE-V4; manufactured by Rheology Co., Ltd.). The measurement frequency is 10 Hz.
Regarding the polypropylene resin composition, the following items were evaluated by injection molding the polypropylene resin composition.

(5) Notched Izod impact strength (J / m)
It measured based on JIS-K-7110.

(6) Tensile strength, tensile elongation at break In accordance with JIS K6251, a test piece was cut from an injection-molded flat plate having a thickness of 2 mm, and the tensile strength and elongation at break were measured. The tensile speed was 500 mm / min and the measurement temperature was 23 ° C.
As the polypropylene resin composition pipe, a pipe having a molding temperature of 200 ° C., an inner diameter of 50 mm, and a thickness of 4.5 mm was molded. The following items were evaluated for the polypropylene resin composition pipe.

(7) Rough surface of pipe
The inner surface of the pipe was visually evaluated to evaluate the surface roughness. The evaluation criteria were set as follows.
No roughening of the pipe surface: ○
The pipe surface is rough: ×
(8) Linear expansion coefficient of pipe A sample was cut into a length of 10 mm, a width of 5 mm, and a thickness of 3 mm in parallel with the longitudinal direction of the pipe, and the linear expansion coefficient in the molding flow direction (longitudinal direction of the pipe) was measured. The measurement measured the range of 23 degreeC-100 degreeC using the thermomechanical analysis (TMA) based on JISK7197, and calculated | required the linear expansion coefficient.

The following materials were used as evaluation materials.
<Polypropylene resin>
-Random type propylene resin; colored polypropylene resin obtained by adding 2% carbon black to Sun Aroma-PS201A (MFR 0.5 g / 10 min, density 0.9 g / cm ³ ) <Hydrogenated Elastomer>
・ Tuftec H1062 (Asahi Kasei Chemicals Corporation)
Styrene content 17.5wt%, vinyl bond 49%, MFR 3g / 10min, loss tangent (tan δ) peak -45 ° C
・ Tuftec H1221 (Asahi Kasei Chemicals Corporation)
Styrene content 13wt%, vinyl bond 77.5%, MFR 4g / 10min, loss tangent (tan δ) peak is -31 ° C
-Olefin elastomer: ethylene-butene copolymer (Toughmer TX610, manufactured by Mitsui Chemicals, Inc.)
MFR 3g / 10min, loss tangent (tan δ) peak is -50 ° C
<Plate filler>
・ Average particle size 4.0 μm talc (trade name: Microace P-4, manufactured by Nippon Talc)
・ Average particle size 13μm talc (trade name: MS manufactured by Nippon Talc, manufactured by Nippon Talc)

[Examples 1 to 3]
Polypropylene resin, hydrogenated elastomer, and plate-like filler are mixed in the proportions shown in Table 1, kneaded with a twin-screw extruder (PCM30 <manufactured by Ikekai Tekko Co., Ltd.>), and pelletized to prepare various polypropylene resin compositions Obtained. The extrusion conditions were a cylinder temperature of 230 ° C. and a rotational speed of 250 rpm. The obtained polypropylene resin composition and its pipe were evaluated.

[Comparative Example 1]
The procedure was the same as in Example 1 except that the formulation is shown in Table 1. The results are shown in Table 1. When a hydrogenated elastomer having many vinyl bonds was used, various physical properties were low and the linear expansion coefficient was high. This is presumably because the compatibility between the polypropylene resin and the hydrogenated elastomer is too high.

[Comparative Example 2]
The procedure was the same as in Example 1 except that the formulation is shown in Table 1. The results are shown in Table 1. In the case of an olefin-based elastomer, a polypropylene resin composition pipe having low mechanical properties and a high linear expansion coefficient was obtained as compared with the case of using a hydrogenated elastomer in the present invention.

[Comparative Example 3]
The procedure was the same as in Example 1 except that the formulation is shown in Table 1. The results are shown in Table 1. In the case of talc having a large average particle size, both the mechanical properties and the linear expansion coefficient were not satisfactory. The surface of the pipe is rough and rough.

[Comparative Example 4]
The procedure was the same as in Example 1 except that the formulation is shown in Table 1. The results are shown in Table 1. When the amount of talc added is too small, the effect of improving the linear expansion coefficient is small.

  A pipe made of a polypropylene resin composition of the present invention has a mechanical property balance, smoothness of the inner surface of the pipe, a low linear expansion coefficient, a chemical plant pipe that requires chemical resistance, heat resistance, etc., which are characteristics of polypropylene resin, Suitable for hot water supply pipes, air conditioning pipes and the like.

Claims (3)

(A) 60-90% by weight of a polypropylene resin, (b) hydrogenated elastomer obtained by hydrogenating a non-hydrogenated elastomer having 10-50% by weight of vinyl aromatic hydrocarbon and 30-70% of the conjugated diene is a vinyl bond 2 to 20% by weight and (c) 5 to 30% by weight of a plate-like filler having an average particle diameter of 0.5 to 10 μm, and a linear expansion coefficient in the range of 5 × 10 ^{−5 to} 12 × 10 ⁻⁵ / ° C. A pipe made of a polypropylene resin composition. (However, component (a) + component (b) + component (c) = 100 wt%)   It is a hydrogenated elastomer having a melt flow rate of 0.1 to 20 g / 10 min at 230 ° C. and a load of 2.16 kg, and a loss tangent (tan δ) peak at −32 ° C. or lower in the dynamic viscoelastic spectrum. A pipe made of a polypropylene resin composition according to claim 1.   3. The pipe made of a polypropylene resin composition according to claim 1 or 2, wherein the plate-like filler is talc and / or mica.