JP2010150357A - Resin composition for blow molding, and molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for blow molding to be a material for blow molding capable of giving excellent rigidity, impact resistance and heat resistant creep properties to an obtained molded product while satisfactory blow moldability is maintained and capable of attaining thinness and lightness in weight of the molded product and to provide the molded product. <P>SOLUTION: The resin composition for blow molding includes the following components (a) to (d). A component (a):100 pts.wt. polyethylene having 0.910 to 0.970 g/cm<SP>3</SP>density and 0.001 to 50 g/10 min melt flow rate at 21.6 kg load at 190°C, a component (b): 1 to 100 pts.wt. inorganic filler having 0.1 to 1,500 μm average particle diameter, a component (c): 1 to 100 pts.wt. of a modified polyethylene formed by graft polymerizing 0.001 to 15 wt.% ethylenically unsaturated silane compound to 99.999 to 85 wt.% polyethylene and/or a copolymer of 99.999 to 85 wt.% olefin and 0.001 to 15 wt.% ethylenically unsaturated silane compound, and a component (d): 0.00001 to 10 pts.wt. silanol condensation catalyst. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hollow molding resin composition and a molded article, and more particularly to a hollow molding resin composition and a molded article suitable for multilayer hollow molding. More specifically, in hollow molding materials, while maintaining good hollow moldability, the molded product obtained has excellent rigidity, impact resistance, and heat-resistant creep resistance, and can be made thin and lightweight. The present invention relates to a composition and a molded article.

  In recent years, in the field of hollow molding, resinization of products has been actively promoted for the purpose of weight reduction and energy saving. As the resin material, polyethylene is generally used as a main material from the viewpoints of low cost, high strength, good weather resistance, good chemical resistance, recyclability, and the like.

  Further, in hollow molded articles using polyethylene, further weight reduction is required by reducing the thickness of containers and the like. In order to reduce the thickness, it is necessary to improve the rigidity of the material, and improvement in rigidity by adding a filler has been studied (for example, see Patent Documents 1 to 4).

In Patent Document 1, a polyethylene composition comprising 60 to 95% by weight of polyethylene partially or entirely modified with an unsaturated carboxylic acid or an anhydride thereof and 5 to 40% by weight of an inorganic filler, Manufactured with a chromium catalyst or a catalyst obtained by reducing the chromium catalyst with a reducing agent, high load melt flow rate (HLMFR) (190 ° C., 21.6 kg load) is 1 to 100 g / 10 min, density is 930 kg / m ³ A polyethylene composition characterized by the above is disclosed, and a polyethylene resin composition having excellent rigidity, impact resistance, reclaiming properties, and good blow molding performance such as draw-down resistance has been proposed.

Patent Document 2 discloses a propylene-α-olefin having a crystal melting point of 160 to 165 ° C., a melt flow rate (230 ° C.) of 0.1 to 1 g / 10 min, and a density of 0.895 to 0.905 g / cm ^3. Copolymer 85-50% by weight, melt flow rate (190 ° C.) of 0.06-0.005 g / 10 min, density of 0.945-0.970 g / cm ³ of high-density polyethylene 5-15% by weight, melt An ethylene-α-olefin copolymer having a flow rate (190 ° C.) of 0.01 to 20 g / 10 min, a density of 0.880 to 0.910 g / cm ³ , and a crystal melting point of 110 to 117 ° C. And a hollow molding resin composition having a melt flow rate (230 ° C.) of 5 to 20% by weight of talc having an average particle size of 10 μm or less and 0.1 to 0.8 g / 10 min. Therefore, a hollow molding resin composition has been proposed that has good moldability during molding of large hollow molded products, and has excellent coating, impact resistance, rigidity, heat resistance rigidity, and sharpness of the resulting large hollow molded products. ing.

  Patent Document 3 also includes a filler-filled thermoplastic composition containing a thermoplastic polymer, an unfired filler, a fired filler having an average particle size of less than 2.5 microns and a maximum particle size of 13 microns or less, and a mixture thereof. A method for its production has been disclosed, and a thermoplastic composition with an improved balance of processability, toughness and hardness has been proposed with improved scratch resistance in extruded or molded articles.

Further, Patent Document 4 describes (a) modified polyethylene and / or olefin 99.999 to 85% by weight obtained by grafting 0.001 to 15% by weight of ethylenically unsaturated silane compound to 99.999 to 85% by weight of polyethylene. And 100 parts by weight of a copolymer of 0.001 to 15% by weight of an ethylenically unsaturated silane compound, (b) 0.001 to 10 parts by weight of a silanol condensation catalyst, and more preferably (c) a specific density , A crosslinkable resin for hollow molded fuel tanks containing 100 to 1000 parts by weight of polyethylene having melt flow rate and Olsen bending stiffness, and a molded article using the same, and a large size excellent in balance between moldability and durability Crosslinkable resin for fuel tanks, which is a material for containers, especially hollow with excellent balance of hollow moldability, durability and impact resistance, and excellent fire resistance Fuel tank crosslinkable resin and molded product using the same have been proposed. Patent Document 4 describes that, for example, a filler or the like may be added as long as the effects of the present invention are not impaired, but no further means for improving rigidity is disclosed.
Although the above-described conventional technology can be expected to improve the rigidity within the predicted range by the filler, there is a problem that when the thickness is reduced, a sufficient lightening effect cannot be exhibited due to the influence of the filler density. Moreover, it cannot always be said that it is a sufficient level also from the viewpoint of the physical property balance of the molded product, and further reduction in thickness and weight and improvement in the physical property balance are demanded by further increasing the rigidity.
Japanese Patent Application Laid-Open No. 08-085743 JP 09-031268 A JP 2004-529240 A JP 2008-024729 A

  In view of the above problems, the object of the present invention is to provide a hollow molding resin composition having an excellent balance between moldability and durability, in particular, having a balanced multilayer hollow moldability, durability, impact resistance, and An object of the present invention is to provide a hollow molding resin composition capable of achieving a reduction in thickness and weight of a molded product container by improving rigidity and a molded product using the same.

  The present inventor has intensively studied to solve the above-mentioned problems, and as a result of studying a material that can be sufficiently adapted to reduce the thickness and weight of a hollow molded product, specific polyethylene, inorganic filler, polyethylene containing an ethylenically unsaturated silane compound, etc. And a silanol catalyst-containing resin composition, it has been found that a material having higher rigidity than expected can be realized, and a molded product container can be thinned, and the present invention has been completed.

That is, according to the first invention of the present invention, there is provided a hollow molding resin composition comprising the following components (a) to (d).
Component (a): Polyethylene having a density of 0.910 to 0970 g / cm ³ and a melt flow rate at 190 ° C. under a load of 21.6 kg of 0.001 to 50 g / 10 minutes 100 parts by weight Component (b): Average Inorganic filler having a particle size of 0.1 to 1500 μm 1 to 100 parts by weight Component (c): Modified by grafting 0.001 to 15% by weight of ethylenically unsaturated silane compound to 99.999 to 85% by weight of polyethylene Copolymer of polyethylene and / or olefin 99.999 to 85% by weight and ethylenically unsaturated silane compound 0.001 to 15% by weight 1 to 100 parts by weight Component (d): Silanol condensation catalyst 0.00001 to 10% by weight Part

According to the second invention of the present invention, in the first invention, the polyethylene as the component (a) has a density of 0.940 to 0.965 g / cm ³ and is 190 ° C. under a load of 21.6 kg. A hollow molding resin composition characterized by having a melt flow rate of 0.1 to 30 g / 10 min is provided.
Furthermore, according to the third invention of the present invention, in the first or second invention, the inorganic filler of component (b) is selected from the group consisting of talc, mica, silica, clay and hydrotalcite. A resin composition for hollow molding is provided.

According to the fourth invention of the present invention, in any one of the first to third inventions, the ethylenically unsaturated silane compound of component (c) is a compound represented by the following general formula (I): A hollow molding resin composition is provided.
R ¹ SiR ² _n Y _3-n (I)
[In the formula (I), R ¹ represents an ethylenically unsaturated hydrocarbon group or hydrocarbonoxy group, R ² represents a hydrocarbon group, Y represents a hydrolyzable organic group, and n is an integer of 0 to 2. . ]

  According to a fifth invention of the present invention, in any one of the first to fourth inventions, the silanol condensation catalyst of component (d) is dibutyltin dilaurate or dioctyltin dilaurate. A resin composition is provided.

According to a sixth aspect of the present invention, there is provided a hollow molding resin composition satisfying the following characteristics (1) to (4) in any one of the first to fifth aspects: Is done.
Characteristic (1): The density before crosslinking is 0.910 to 0.970 g / cm ³ .
Characteristic (2): The melt flow rate at 190 ° C. and 21.6 kg load before crosslinking is 0.001 to 50 g / 10 min.
Characteristic (3): Olzen bending stiffness after crosslinking is 700 MPa or more.
Characteristic (4): The gel fraction after crosslinking is 5% or more.

According to a seventh aspect of the present invention, there is provided a multilayer hollow molded article characterized by using the hollow molding resin composition according to any one of the first to sixth aspects as an outermost layer.
Furthermore, according to the eighth invention of the present invention, there is provided a multilayer hollow molded article characterized by using the hollow molding resin composition according to any one of the first to sixth inventions as an innermost layer.

  According to the present invention, a hollow molding resin composition having an excellent balance between moldability and durability, particularly a molded product container having an excellent balance of multilayer hollow moldability, durability and impact resistance, and improved material rigidity. It is possible to obtain a hollow molding resin composition capable of achieving a reduction in thickness and weight and a molded product using the same.

The resin composition for hollow molding of the present invention is a resin composition containing components (a) to (d), and preferably a resin composition satisfying the following characteristics (1) to (4).
Hereinafter, the components of the resin composition of the present invention, the characteristics of the resin composition, and the molded product made of the resin composition will be described in detail.

1. Component component (a) constituting the crosslinkable resin: polyethylene having a density of 0.910 to 0970 g / cm ³ and a melt flow rate at 190 ° C. under a load of 21.6 kg of 0.001 to 50 g / 10 min. The polyethylene in (1) is a known catalyst such as a Ziegler catalyst, a metallocene catalyst, and a Phillips catalyst, for example, transition metal compounds such as titanium and zirconium, Ziegler catalysts consisting of magnesium compounds, zirconium, hafnium, titanium, etc. It is obtained by mainly polymerizing ethylene using a transition metal compound having at least one cyclopentadienyl group or substituted cyclopentadienyl group as a polymerization catalyst, and a Philips catalyst containing a chromium compound.

The polyethylene according to the present invention is ethylene homopolymerization or one or more comonomers selected from ethylene and an α-olefin having 3 to 20 carbon atoms, preferably 3 to 15 carbon atoms, more preferably 3 to 10 carbon atoms. Can be obtained by copolymerizing to a predetermined density.
Examples of the α-olefin to be copolymerized include propylene, butene-1, pentene-1, 3-methylbutene-1, 3-methylpentene-1, 4-methylpentene-1, hexene-1, octene-1 and decene. -1, tetradecene-1, hexadecene-1, octadecene-1, eicosene-1, and the like, and propylene, butene-1, and hexene-1 are particularly preferable from the viewpoint of durability and economy.
Furthermore, vinyl compounds such as vinylcyclohexane, styrene or derivatives thereof can also be used. These α-olefins may be used alone or in combination of two or more.
The content of α-olefin in the ethylene / α-olefin copolymer is 10% by weight or less, preferably 0.1 to 10% by weight, and more preferably 0.1 to 5% by weight. If the α-olefin content is higher than this, the rigidity decreases, which is not preferable.

  Examples of specific polyethylene in more detail include medium density polyethylene (MDPE) and high density polyethylene (HDPE). Examples of the polyethylene copolymer include an ethylene-propylene copolymer, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid or an ethylene-methacrylic acid copolymer. These polyethylenes can be obtained not only as commercial products but also by known polymerization methods.

  The polyethylene of the component (a) according to the present invention is preferably a polyethylene that satisfies the following characteristics (a1) to (a2).

Characteristic (a1): Density In the present invention, the density of the polyethylene of component (a) is preferably 0.910 g / cm ³ or more and 0.970 g / cm ³ or less, more preferably 0.940 g / cm ³ or more, 0 .965g / cm ³ or less, more preferably 0.940 g / cm ³ or more and 0.960 g / cm ³ or less. When the density is less than 0.910 g / cm ³ , the rigidity of the molded product is insufficient. On the other hand, when the density exceeds 0.970 g / cm ³ , the impact resistance is inferior. The density can be adjusted by changing the amount of α-olefin copolymerized with ethylene.
Here, the density is measured in accordance with JIS K7112 (1999), and the polyethylene pellets are cooled at a rate of 25 ° C./min after melting with a hot compression molding machine at a temperature of 160 ° C., and the thickness is 2 mm. This sheet is molded, and this sheet is held at 23 ° C. for 48 hours, and then placed in a density gradient tube and measured.
The density can be adjusted by changing the amount of α-olefin copolymerized with ethylene, and can be reduced by increasing the amount of α-olefin.

Characteristic (a2): Melt flow rate In the present invention, the melt flow rate of the component (a) polyethylene at 190 ° C. under a load of 21.6 kg is preferably 0.001 g / 10 min or more and 50 g / 10 min or less, more preferably. Is 0.005 g / 10 min or more and 30 g / 10 min or less, more preferably 0.01 g / 10 min or more and 10 g / 10 min or less. When the melt flow rate is less than 0.001 g / 10 min, the extrusion amount becomes insufficient during hollow molding, and the molding becomes unstable, which is not practical. Moreover, when it exceeds 10 g / 10 minutes, the shaping | molding defect by drawdown deterioration will generate | occur | produce. The adjustment of the melt flow rate at 190 ° C. and a load of 21.6 kg can be performed, for example, by changing the amount of hydrogen coexisting during ethylene polymerization.
Here, the melt flow rate is measured under test conditions of 190 ° C. and a load of 21.6 kg in accordance with JIS K7210 (1999).
The melt flow rate can be adjusted by changing the amount of chain transfer agent (hydrogen, etc.) coexisting during ethylene polymerization or by changing the polymerization temperature, increasing the amount of hydrogen or raising the polymerization temperature. It can be enlarged.

Characteristic (a3): Olsen bending stiffness In the present invention, the Olsen bending stiffness of the component (a) polyethylene is preferably 600 MPa or more and 1300 MPa or less, more preferably 600 MPa or more and 1250 MPa or less, and further preferably 650 MPa or more and 1200 MPa. It is as follows. If the Olsen bending rigidity is less than 600 MPa, the rigidity of the molded product becomes insufficient. On the other hand, if it exceeds 1300 MPa, the impact resistance decreases.
Here, the Olsen bending stiffness is measured in accordance with JIS K7106 (1995), and cantilever bending stress is 60 deg / min under the conditions of span of 30 mm, gripping part of 30 mm, and total bending moment of 6 kgf · cm. Is to measure.
The Olsen bending stiffness can be adjusted by increasing or decreasing the molecular weight and density of polyethylene, and increasing the molecular weight or density can increase the flexural modulus.

  In the present invention, the polyethylene of component (a) may be a single polyethylene as long as it satisfies the above characteristics (a1) to (a2), but a plurality of, for example, polyethylene components having two different physical properties It can also consist of. In particular, the polyethylene used in the present invention is preferably a polyethylene obtained by a continuous multistage polymerization method, and is a so-called polyethylene composition obtained by polymerizing a predetermined polyethylene component separately and then polymer-blending a predetermined amount. It can be mixed.

  In the present invention, various known additives, fillers, and the like can be added to the polyethylene of component (a) in appropriate amounts within a range not significantly impairing the effects of the present invention. Examples of the additive include one or more antioxidants (phenolic, phosphorus, sulfur), lubricants, antistatic agents, light stabilizers, colorants, pigments, dyes, ultraviolet absorbers, compatibilizers, and the like. Two or more kinds can be used together as appropriate. Moreover, as a filler, talc, mica, etc. can be used, for example. In addition, the polyethylene used in the present invention can be modified with maleic anhydride or the like, if necessary.

  The blending amount of the component (a) polyethylene of the present invention is based on 100 parts by weight, and other components are blended in a predetermined weight ratio with respect to 100 parts by weight of the component (a) polyethylene.

Component (b): Inorganic filler having an average particle size of 0.1 to 1500 μm In the present invention, the inorganic filler of component (b) is silica, diatomaceous earth, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide. , Oxides such as iron oxide, tin oxide, antimony oxide, ferrite, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, hydroxides such as basic magnesium carbonate, calcium carbonate, magnesium carbonate, zinc carbonate, barium carbonate, Carbonate such as dawsonite, hydrotalcite, sulfate such as calcium sulfate, barium sulfate, gypsum fiber, calcium silicate (wollastonite, zonotlite), talc, clay, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite , Sericite, glass fiber, glass Silicates such as silica balloons, nitrides such as aluminum nitride, boron nitride, and silicon nitride, carbon black, graphite, carbon fiber, carbon balloon, charcoal powder, carbon nanotubes, carbons such as fullerene, various types Examples include metal powder, potassium titanate, lead zirconate titanate, aluminum borate, molybdenum sulfide, silicon carbide, stainless steel fiber, zinc borate, various magnetic powders, and slag fiber.
These inorganic fillers can be used alone or in combination of two or more. As the inorganic filler, those subjected to surface treatment with various surfactants, silane coupling agents, and the like are preferably used.
Among the inorganic fillers, talc, mica, silica, clay, and hydrotalcite are preferable from the viewpoint of improving dispersibility and physical properties, and more preferably, talc and mica are preferable.

These inorganic fillers have an average particle diameter of 0.1 to 1500 μm, preferably 0.1 to 500 μm, and an average aspect ratio of 1 to 300, preferably 5 to 200.
Particularly preferable examples include mica and talc having an average particle diameter of 8 to 100 μm and an average aspect ratio of 10 to 100. The average particle diameter of the inorganic filler (b) of the present invention is measured according to JIS Z8901-1995.
When the average particle size and average aspect ratio are less than the above ranges, the rigidity improvement effect of the multilayer hollow molded article tends to be insufficient. On the other hand, when it exceeds the above ranges, mechanical strength such as impact strength decreases. There is a tendency.

The density of the inorganic filler of component (b) is preferably 2.0 to 3.0 g / cm ³ .
The inorganic filler used may be a new filler, a filler used for one or more moldings, or a filler combining the above.
The blending ratio of the inorganic filler of component (b) is 1 to 100 parts by weight, preferably 10 to 90 parts by weight, and more preferably 30 to 80 parts by weight with respect to 100 parts by weight of polyethylene of component (a). When the blending ratio of the inorganic filler of the component (b) is less than the lower limit value, the rigidity improving effect is lowered, whereas when the upper limit value is exceeded, the impact strength is lowered.

Component (c): modified polyethylene (c-1) obtained by grafting 0.001 to 15% by weight of ethylenically unsaturated silane compound to 99.999 to 85% by weight of polyethylene and / or 99.999 to 85% by weight of olefin Copolymer with ethylenically unsaturated silane compound 0.001 to 15% by weight (c-2)
Examples of the polyethylene in the modified polyethylene (c-1) obtained by grafting an ethylenically unsaturated silane compound on the polyethylene of the component (c) used in the resin composition for hollow molding of the present invention include known Ziegler catalysts and metallocene catalysts. Each catalyst, for example, generally, a transition metal compound such as titanium or zirconium, a Ziegler catalyst composed of a magnesium compound, a transition metal compound such as zirconium, hafnium or titanium, and at least one cyclopentadienyl group or substituted cyclopentadi It can be obtained by mainly polymerizing ethylene using a metallocene-based catalyst having an enyl group as a polymerization catalyst.

In the polymerization of ethylene, the polyethylene according to the present invention is one or more selected from ethylene homopolymerization or ethylene and an α-olefin having 3 to 20, preferably 3 to 15 and more preferably 3 to 10 carbon atoms. It is obtained by copolymerizing the comonomer to a predetermined density. Examples of the α-olefin to be copolymerized include propylene, butene-1, pentene-1, 3-methylbutene-1, 3-methylpentene-1, 4-methylpentene-1, hexene-1, octene-1 and decene. -1, tetradecene-1, hexadecene-1, octadecene-1, eicosene-1, and the like, and propylene, butene-1, and hexene-1 are particularly preferable from the viewpoint of durability and economy.
Furthermore, vinyl compounds such as vinyl acetate, acrylic acid, methacrylic acid, vinylcyclohexane, styrene or derivatives thereof can also be used.
These α-olefins may be used alone or in combination of two or more.
The content of α-olefin in the ethylene / α-olefin copolymer is 10% by weight or less, preferably 0.1 to 10% by weight, and more preferably 0.1 to 5% by weight. If the α-olefin content is higher than this, the rigidity decreases, which is not preferable.

  Examples of specific polyethylene in more detail include medium density polyethylene (MDPE) and high density polyethylene (HDPE). Examples of the polyethylene copolymer include ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid or ethylene-methacrylic acid copolymer. These polyethylenes can be obtained not only as commercial products but also by known polymerization methods.

Examples of the ethylenically unsaturated silane compound in the modified polyethylene (c-1) obtained by grafting an ethylenically unsaturated silane compound to the polyethylene of the component (c) used in the resin composition of the present invention include hydrolyzable groups and ethylene. The compound represented by the following general formula (I) is preferable.
R ¹ SiR ² _n Y _3-n (I)
[In the formula (I), R ¹ represents an ethylenically unsaturated hydrocarbon group or hydrocarbonoxy group, R ² represents a hydrocarbon group, Y represents a hydrolyzable organic group, and n is an integer of 0 to 2. . ]

Here, examples of R ¹ include a vinyl group, propenyl group, butenyl group, cyclohexenyl group, γ- (meth) acryloyloxypropyl group, and examples of R ² include a methyl group, an ethyl group, and a propyl group. , Decyl group, phenyl group and the like, and examples of Y include, for example, methoxy group, ethoxy group, formyloxy group, acetoxy group, propionyloxy group, alkylamino group, arylamino group, etc. Specific examples of the unsaturated silane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

  The modified polyethylene (c-1) used in the present invention is obtained by graft-reacting 0.001 to 15% by weight of an ethylenically unsaturated silane compound to 99.999 to 85% by weight of the above polyethylene. If the amount of the ethylenically unsaturated silane compound is less than 0.001% by weight, the crosslinking is insufficient and the rigidity is insufficient. It becomes easy to do.

  The graft reaction can be performed by a known method. For example, it can be obtained by reacting polyethylene with an ethylenically unsaturated silane compound in the presence of a radical initiator. The radical initiator may be any compound that has a decomposition temperature equal to or higher than the melting point of the olefin resin to be used and is generally used for graft reaction of the olefin resin. For example, benzoyl peroxide, 2,4- Dichlorobenzoyl peroxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, di-t-butylper Oxides, organic peroxides such as 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, azo compounds such as azobisisobutyronitrile, dimethylazodiisobutyrate, and the like. . These may be used alone or in combination of two or more. Among them, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butyl) One or more of peroxy) hexyne-3 and the like are more preferably used.

  Although the usage-amount of the said radical initiator is not specifically limited, Preferably it is 0.01-5 weight part with respect to 100 weight part of said polyethylenes, More preferably, it is 0.02-2 weight part. If the amount of radical initiator used is too small, the grafting reaction will not proceed sufficiently and the desired gel fraction cannot be obtained. Conversely, if it is too large, excessive free radicals are generated in the polyethylene molecule, so-called peroxides. Crosslinking progresses, scorch is generated, surface smoothness is lowered, viscosity is abnormally increased, and workability is deteriorated.

  The modified polyethylene (c-1) can also be produced according to the method described in Japanese Patent Publication No. 48-1711. However, it is not limited to this method, and it can be produced by a suitably modified method.

  In the present invention, the copolymer (c-2) of an olefin and an ethylenically unsaturated silane compound used in the component (c) is an olefin of 99.999 to 85 weight and an ethylenically unsaturated silane compound of 0.001 to 0.001. It is obtained by copolymerizing 15% by weight. When the amount of the ethylenically unsaturated silane compound is less than 0.001% by weight, the crosslinking is insufficient and the rigidity is insufficient. On the other hand, when the amount exceeds 15% by weight, fish eyes, bumps, etc. are generated in the crosslinked resin. It becomes easy to do.

The copolymerization reaction can be carried out by a known method, and can be produced, for example, according to the method described in JP-A-55-9611. However, it is not limited to this method, and it can be produced by a suitably modified method.
Examples of the olefin include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, and butene-1, and the ethylenically unsaturated silane compound is the same as the compound used in (c-1). Can be used.

  As the component (c) used in the resin composition for hollow molding of the present invention, the above components (c-1) and (c-2) may be used alone or in combination. .

  Modified polyethylene (c-1) and / or olefin 99.999 to 85% by weight obtained by grafting 0.001 to 15% by weight of an ethylenically unsaturated silane compound to 99.999 to 85% by weight of polyethylene of component (c), The blending ratio of the copolymer (c-2) with 0.001 to 15% by weight of the ethylenically unsaturated silane compound is 1 to 100 parts by weight, preferably 10 parts per 100 parts by weight of the polyethylene of the component (a). -50 parts by weight, more preferably 20-40 parts by weight. If the blending ratio of the component (c) is less than the lower limit value, the rigidity improving effect is lowered, while if the blending ratio exceeds the upper limit value, the impact strength is lowered.

Component (d): Silanol condensation catalyst As the (d) silanol condensation catalyst used in the hollow molding resin composition of the present invention, a catalyst usually used for ester hydrolysis can be used, and examples thereof include an acid catalyst and a base catalyst. Among them, any compound generally used as a catalyst for promoting dehydration condensation between silanols is preferable, for example, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, dibutyltin dioctoate, stannous acetate, Stannous octoate, cobalt naphthenate, lead naphthenate, zinc caprylate, iron 2-ethylhexanoate, tetrabutyl titanate, tetranonyl titanate, bis (acetylacetonitrile) di-isopropyl titanate, ethylamine, di Butylamine, hexylamine, pyridine Examples thereof include inorganic acids such as sulfuric acid and hydrochloric acid, organic acids such as toluenesulfonic acid, acetic acid, stearic acid, and maleic acid, and one or more of these are preferably used. Dilaurate and dioctyltin dilaurate are more preferably used.

  The compounding amount of the silanol condensation catalyst of component (d) in the resin composition for hollow molding of the present invention is 0.00001 to 10 parts by weight, preferably 0.0001 to 100 parts by weight of component (a). 10 parts by weight, more preferably 0.001 to 8 parts by weight. If the amount of component (d) is less than 0.00001 parts by weight, the crosslinking reaction is slow, while if it exceeds 10 parts by weight, fish eyes and blisters are likely to occur in the crosslinked resin.

The method of using the silanol condensation catalyst used in the present invention is a method in which the catalyst is mixed with the modified polyethylene and / or copolymer powder or pellets of an olefin and an ethylenically unsaturated silane compound, and the catalyst is in the middle of an extruder. Or by applying the catalyst as a solution or a dispersion on the surface of a molded article obtained from a copolymer of modified polyethylene and / or olefin and ethylenically unsaturated silane compound, or Further, a method of impregnating the molded article into the solution or dispersion is employed.
Among them, in the present invention, the silanol condensation catalyst is a copolymer of the modified polyethylene and / or olefin and an ethylenically unsaturated silane compound together with the olefin resin powder, the ethylenically unsaturated silane compound, and a radical generator. It is preferable to use a method in which the catalyst is mixed together with the powder or pellets, or a method in which the catalyst is press-fitted from an injection hole provided in the middle of the extruder. In particular, when the crosslinkable resin according to the present invention is produced, it may be mixed as it is, or preferably used in advance with a small amount of polyethylene or the like from the viewpoint of dispersibility.

  The resin composition in the present invention includes a thermoplastic resin and rubber, an antioxidant, a light stabilizer, an ultraviolet absorber, a nucleating agent, a neutralizing agent, and an antistatic agent as long as the effects of the present invention are not impaired. Further, a lubricant, an antiblocking agent, a dispersant, a fluidity improver, a plasticizer, a release agent, a flame retardant, a colorant, a filler, a compatibilizer, an adhesive, and the like may be added.

2. Characteristics of Resin Composition The hollow molding resin composition of the present invention contains the above components, but preferably has the following characteristics (1) to (4).

Characteristic (1): Density before crosslinking The density before crosslinking of the resin composition for hollow molding of the present invention is 0.910 g / cm ³ or more and 0.970 g / cm ³ or less, preferably 0.940 g / cm 3. ³ or more and 0.965 g / cm ³ or less, more preferably 0.940 g / cm ³ or more and 0.960 g / cm ³ or less. If the density before cross-linking is less than 0.910 g / cm ³ , the molded product has insufficient rigidity, while if it exceeds 0.970 g / cm ³ , the impact resistance is poor.
Here, the density of the resin composition is measured in accordance with JIS K7112 (1999), and the resin composition is cooled at a rate of 25 ° C./min after being melted by a hot compression molding machine having a temperature of 160 ° C. Then, a sheet having a thickness of 2 mm is formed, and this sheet is held at 23 ° C. for 48 hours, and then placed in a density gradient tube and measured. The density of the resin before cross-linking is measured so as not to come into contact with moisture.
The density can be adjusted by changing the amount of α-olefin copolymerized with ethylene, and can be reduced by increasing the amount of α-olefin.

Characteristic (2): Melt flow rate before crosslinking The melt flow rate at 190 ° C. and 21.6 kg load before crosslinking of the resin composition for hollow molding of the present invention is 0.001 g / 10 min or more and 50 g / 10 min or less. It is preferably 0.005 g / 10 min or more and 30 g / 10 min or less, more preferably 0.010 g / 10 min or more and 10 g / 10 min or less. When the melt flow rate before cross-linking is less than 0.001 g / 10 min, the extrusion amount is insufficient at the time of hollow molding, and the molding becomes unstable, which is not practical. On the other hand, if it exceeds 50 g / 10 minutes, the impact resistance of the molded product is lowered.
Here, the melt flow rate at 190 ° C. and a load of 21.6 kg of the resin composition is measured in accordance with JIS K7210 (1999). The melt flow rate of the resin before cross-linking is measured so as not to come into contact with moisture.
The melt flow rate can be adjusted by changing the amount of chain transfer agent (such as hydrogen) coexisting during ethylene polymerization or by changing the polymerization temperature, increasing the amount of hydrogen or increasing the polymerization temperature. By doing so, it can be enlarged.

Characteristic (3): Olzen bending stiffness after crosslinking The Olsen bending stiffness after crosslinking of the hollow molding resin composition of the present invention is 700 MPa or more, preferably 750 MPa or more, 1500 MPa or less, more preferably 800 MPa or more, 1250 MPa or less. If the Olsen bending rigidity is less than 700 MPa, the rigidity of the molded product becomes insufficient. On the other hand, if it exceeds 1500 MPa, the impact resistance decreases.
Here, the Olsen bending stiffness after crosslinking of the resin composition is measured in accordance with JIS K7106 (1995), and is 60 deg under the conditions of 30 mm span, 30 mm gripping portion, and total bending moment of 6 kgf · cm. Measures cantilever bending stress at 1 min.
The Olsen bending stiffness can be adjusted by increasing or decreasing the molecular weight and density of polyethylene, and increasing the molecular weight or density can increase the flexural modulus.

Characteristic (4): Gel fraction after crosslinking The gel fraction after crosslinking of the resin composition for hollow molding of the present invention is 5% or more, preferably 7% or more, more preferably 10% or more, 95% or less. When the gel fraction is less than 5%, the rigidity of the molded product is lowered. The degree of cross-linking (gel fraction) can be adjusted by appropriately changing the amount of the above-mentioned ethylenically unsaturated silane compound or the like according to the intended physical properties, such as ethylenically unsaturated silane compound or the like. Increasing the amount increases the gel fraction.
The hollow molding resin composition of the present invention can be cross-linked by exposure to water atmosphere or contact with water, and the cross-linked one has a high gel fraction, thermal characteristics, mechanical characteristics, Chemical characteristics are improved, and a molded article suitable as a fuel tank can be obtained.
Here, the gel fraction after crosslinking is in accordance with JIS K6787 (1997), and 10 g of a sample is extracted at a boiling temperature for 24 hours by a Soxhlet type extractor using xylene as a solvent, and the extraction residue after drying the solvent. The weight of the minute is calculated according to the following formula.
Gel fraction (%) = weight of extraction residue (g) × 100 / weight of sample before extraction (g)
In the calculation of the gel fraction, the calculation is performed excluding the component (b) which is a filler.

3. Molded Product The molded product of the present invention is obtained by molding the above resin composition by a known molding method and then crosslinking. As the molding method, multilayer hollow molding is preferred. The cross-linking method is preferably so-called water cross-linking, and the product obtained by molding the resin composition of the present invention is molded into liquid or vapor water at room temperature to about 200 ° C., usually from room temperature to about 100 ° C. for 1 hour. It is preferable that the contact is performed for about 1 week, usually about 3 to 12 hours. Even in a state where the temperature is 23 ° C. and the humidity is 50%, the effect can be obtained when left for about 10 days.

  As a molded article molded from the resin composition for hollow molding of the present invention, a hollow molded article by multilayer hollow molding is particularly preferable, and it is suitably used as various containers.

  As a particularly preferred embodiment of the hollow molded article, a multilayer hollow molded article using the hollow molding resin composition of the present invention as the outermost layer or the innermost layer can be mentioned.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to these Examples.
The physical properties of the resin are measured by the following method. When measuring the physical properties of the resin before cross-linking, the resin is not in contact with moisture, and when measuring the physical properties of the resin after cross-linking, the cross-linked resin is treated as moisture. Performed on the sample after contact.

1. Physical properties of resin (1) Density: Measured according to JIS K7112 (1999).
(2) Melt flow rate at 190 ° C. and 21.6 kg load: measured in accordance with JIS K7210 (1999).
(3) Olsen bending stiffness: Based on JIS K7106 (1995), the cantilever bending stress was measured at 60 deg / min under the conditions of 30 mm between spans, 30 mm gripping portion, and total bending moment of 6 kgf · cm.
(4) Gel fraction: In accordance with JIS K6787 (1997), 10 g of a sample was extracted at a boiling temperature for 24 hours with a Soxhlet type extractor using xylene as a solvent, and the weight of the extraction residue after solvent drying was determined. Calculation was performed according to the following formula.
Gel fraction (%) = weight of extraction residue (g) × 100 / weight of sample before extraction (g)
In the calculation of the gel fraction, the calculation was performed excluding the component (b) as the filler.

(5) Hollow moldability: The drawdown resistance and thickness uniformity of the parison at the time of hollow molding were evaluated.
(6) Low temperature drop strength: cylindrical shape, 300mm in height, 110mm in outer diameter, average thickness of 1mm in the body, 30mm in outer diameter of the mouth, with a handle type of internal volume 1500ml hollow bottle, and injected antifreeze into the bottle Then, it cooled to -20 degreeC, the drop test was implemented so that a bottom face may contact the ground from 1m in height, making the bottom face downward. The number of samples was 5, and the presence or absence of cracks was confirmed.
0% when there is no crack, 20% when 1 is broken, 40% when 2 is broken, 60% when 3 is broken, 80% when 4 is broken, 80% when 4 is broken, and when all 5 are broken Was 100%. In the judgment, ◎ is given when there is no crack, and x is given when even one crack is found.
(7) Environmental stress crack resistance (bottle ESCR): Measured according to ASTM D1693.
500 hours or more were evaluated as ◎, 50 hours or more but less than 500 hours as ◯, 10 hours or more but less than 50 hours as Δ, and less than 10 hours as x.
(8) Buckling strength: The container was set up vertically, and compressed in the vertical direction from the upper part to the lower part of the container at a speed of 50 mm / min.
When the buckling strength converted to a plate thickness of 1 mm exceeds 550 kg, ◎, when it exceeds 450 kg and 550 kg or less, ◯, when it exceeds 400 kg and 450 kg or less, Δ, and when it is 400 kg or less, ×.
(9) Heat resistant creep property: 80 ° C. warm water was poured into the container, and the elongation strain of the entire container when it was held at the cap mouth was measured.
◎ when elongation strain% is 4% or less, ○ when elongation strain% is over 4% and 8% or less, △ when elongation strain% is over 8% and 12% or less, and elongation strain% is 12% The case where it exceeded was made into x.
(10) Molded product thickness: The plate thickness was measured at the flat portion at the center of the container.

2. Materials used (1) Polyethylene of component (a):
HDPE1: Novatec HB233R (density 0.946 g / cm ³ , 190 ° C., polyethylene having a melt flow rate of 0.3 g / 10 min at a load of 21.6 kg and an Orzen bending rigidity of 1000 MPa) manufactured by Nippon Polyethylene Co., Ltd. was used.
HDPE2: Novatec HB111R (density 0.945 g / cm ³ , 190 ° C., polyethylene with melt flow rate of 0.03 g / 10 min at 21.6 kg load and Olsen bending stiffness of 900 MPa) manufactured by Nippon Polyethylene Co., Ltd. was used.

(2) Inorganic filler of component (b):
Talc 1: Talc (Micron White 5000S manufactured by Hayashi Kasei Co., Ltd.) having an average particle diameter of 4 μm and an average aspect ratio of 10 was used.
Mica 1: Mica (Yarn Mica WG-325W manufactured by Hayashi Kasei Co., Ltd.) having an average particle size of 4 μm and an average aspect ratio of 30 was used.

(3) Modified polyethylene obtained by grafting an ethylenically unsaturated silane compound onto polyethylene of component (c) Modified PE1: Using a Ziegler catalyst, hexene-1 as a comonomer, and a density of 0.948 g / cm by slurry polymerization. ^3. Polyethylene (I) having a melt flow rate of 15 g / 10 min at 190 ° C. under a load of 2.16 kg and an Olzen bending stiffness of 900 MPa was produced.
Next, 3 parts by weight of vinyltriethoxysilane (“SZ6300 SILANE” manufactured by Toray Dow Corning Silicone Co., Ltd.) as an ethylenically unsaturated silane compound and 2,5- After adding 0.1 part by weight of dimethyl-2,5-di (benzoylperoxy) hexane (“Perhexa 25B” manufactured by Nippon Oil & Fats Co., Ltd.) and mixing with a Henschel mixer, using an extruder with a caliber of 50 mm and L / D24, By melt-kneading at 190 ° C., modified polyethylene (I) (density 0.946 g / cm ³ , 190 ° C., melt flow rate at a load of 2.16 kg of 0.3 g / 10 min) was produced and used.

(4) Silanol condensation catalyst of component (d) Dibutyltin dioctate (“SANN = SNT = 1F” manufactured by Sansha Co., Ltd.) was used.

[Example 1]
To 100 parts by weight of HDPE1, 0.05 part by weight of dibutyltin dioctate (“STANN = SNT = 1F” manufactured by Sansha Kogyo Co., Ltd.) was added and melted at 190 ° C. with an extruder having a diameter of 50 mm and L / D24. Kneaded.
Next, 7 parts by weight of talc 1 and 27 parts by weight of modified PE1 are added to 100.05 parts by weight of the kneaded product (100 parts by weight of HDPE and 0.05 parts by weight of dibutyltin dioctate), and the caliber is 50 mm, L / L It melt-kneaded at 190 degreeC with the extruder of D24.
Using the obtained resin composition, a bottle having a volume of 1500 ml was molded under the conditions of a molding temperature of 200 ° C. and a blowing time of 40 seconds using a small blow molding machine (manufactured by Modern Machinery). The molded product weight was about 80 g.
This bottle was immersed in warm water at 90 ° C. for 6 hours to obtain a crosslinked molded product. The molded article was evaluated for low temperature drop strength, bottle ESCR, buckling strength, heat-resistant creep resistance, Olsen bending rigidity, gel fraction, and the like. The results are shown in Table 1.
The resin composition had good hollow moldability, and both the environmental stress crack resistance (bottle ESCR) evaluation by the bottle was good, and the effect of reducing the thickness and weight was great.

[Examples 2 to 7]
Table 1 shows the results obtained in the same manner as in Example 1 except that the composition shown in Table 1 was used.
The resin composition had good hollow moldability, and both the environmental stress crack resistance (bottle ESCR) evaluation by the bottle was good, and the effect of reducing the thickness and weight was great.

[Comparative Examples 1 to 7]
Table 2 shows the results obtained in the same manner as in Example 1 except that the composition shown in Table 2 was used.
The resin composition has poor low-temperature drop strength, bottle ESCR, buckling strength, or heat-resistant creep resistance, and is insufficient as a hollow molded article material.

  The molded product obtained from the resin composition for hollow molding of the present invention has an excellent balance between moldability and durability, is particularly high in rigidity, can reduce the thickness and weight of the molded product, and is industrially very useful. Is high.

Claims (8)

A hollow molding resin composition comprising the following components (a) to (d):
Component (a): Polyethylene having a density of 0.910 to 0970 g / cm ³ and a melt flow rate at 190 ° C. under a load of 21.6 kg of 0.001 to 50 g / 10 minutes 100 parts by weight Component (b): Average Inorganic filler having a particle size of 0.1 to 1500 μm 1 to 100 parts by weight Component (c): Modified by grafting 0.001 to 15% by weight of ethylenically unsaturated silane compound to 99.999 to 85% by weight of polyethylene Copolymer of polyethylene and / or olefin 99.999 to 85% by weight and ethylenically unsaturated silane compound 0.001 to 15% by weight 1 to 100 parts by weight Component (d): Silanol condensation catalyst 0.00001 to 10% by weight Part The polyethylene of component (a) has a density of 0.940 to 0.965 g / cm ³ and a melt flow rate at 190 ° C. and a load of 21.6 kg of 0.1 to 30 g / 10 min. The resin composition for hollow molding according to claim 1.   3. The resin composition for hollow molding according to claim 1 or 2, wherein the inorganic filler of component (b) is an inorganic filler selected from the group consisting of talc, mica, silica, clay and hydrotalcite. . The resin composition for hollow molding according to any one of claims 1 to 3, wherein the ethylenically unsaturated silane compound of component (c) is a compound represented by the following general formula (I): .
R ¹ SiR ² _n Y _3-n (I)
[In the formula (I), R ¹ represents an ethylenically unsaturated hydrocarbon group or hydrocarbonoxy group, R ² represents a hydrocarbon group, Y represents a hydrolyzable organic group, and n is an integer of 0 to 2. . ]   The hollow molding resin composition according to any one of claims 1 to 4, wherein the silanol condensation catalyst of component (d) is dibutyltin dilaurate or dioctyltin dilaurate. The hollow molding resin composition according to any one of claims 1 to 5, wherein the following characteristics (1) to (4) are satisfied.
Characteristic (1): The density before crosslinking is 0.910 to 0.970 g / cm ³ .
Characteristic (2): The melt flow rate at 190 ° C. and 21.6 kg load before crosslinking is 0.001 to 50 g / 10 min.
Characteristic (3): Olzen bending stiffness after crosslinking is 700 MPa or more.
Characteristic (4): The gel fraction after crosslinking is 5% or more.   A multilayer hollow molded article, wherein the hollow molding resin composition according to any one of claims 1 to 6 is used as an outermost layer.   A multilayer hollow molded article, wherein the hollow molding resin composition according to any one of claims 1 to 6 is used as an innermost layer.