JP3345128B2 - Fuel tank using ethylene polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel ethylene polymer .
It relates to a fuel tank that was used. More specifically, in hollow molding, especially in large hollow molding, having a high melt tension,
Excellent moldability such as uniform stretchability and high rigidity,
The present invention relates to a fuel tank having excellent mechanical properties such as impact resistance and using an ethylene polymer having excellent fire resistance and having excellent impact resistance and fire resistance even with a smaller average thickness than conventional products.

[0002]

2. Description of the Related Art In recent years, in the field of automobile industry, plasticization of various automobile parts has been actively promoted for the purpose of weight reduction and energy saving. As a plastic material, a polyolefin resin is generally used from the viewpoint of low cost, high strength, good weather resistance, good chemical resistance and environmental problems.

[0003] Among polyolefin resins, polyethylene is particularly suitable as a resin for hollow molding. In general, polyethylene having a relatively wide molecular weight distribution, a large melt tension, and good uniform stretchability is used. In particular, in the field of large-sized hollow molding, recently, large containers such as plastic fuel tanks and drums have attracted attention.
In particular, a plastic fuel tank made of high-molecular-weight, high-density polyethylene makes use of the characteristic that the degree of freedom in shape is higher than that of a conventional fuel tank made of a steel plate.
It is mounted on vehicles equipped with WD (four-wheel drive), 4WS (four-wheel steering), and the like.

[0004]

As a material suitable for such use, for example, an ethylene copolymer excellent in moldability and environmental stress cracking resistance (hereinafter referred to as ESCR) (Japanese Patent Application Laid-Open No. 2-53811). And so on. However, with these high-density polyethylenes, when an attempt is made to manufacture a fuel tank having a complicated shape, the thickness of the curved portion of the obtained fuel tank is reduced, and the strength of that portion is reduced. Therefore, in order to reinforce the strength of the curved portion, the entire fuel tank has to be thickened in order to increase the wall thickness, and as a result, there is an insufficient situation in terms of economy and lightness.

Further, when copolymerization with an α-olefin is carried out for the purpose of improving the mechanical strength such as impact resistance and ESCR of a product, the copolymer has a relatively low density, resulting in a decrease in rigidity. Occurs. Especially for lighter products,
In an attempt to reduce the thickness of the fuel tank, the reduction in rigidity causes problems such as bending when using the fuel tank and deformation when stacking products.

[0006] An object of the present invention is to provide, in such applications, high melt tension, excellent molding properties such as uniform stretchability, high rigidity, excellent mechanical properties such as impact resistance, and excellent fire resistance. Another object of the present invention is to propose a fuel tank using an ethylene-based polymer, which has a small thickness distribution, is thin, is lightweight, is economical, has high rigidity, is excellent in impact resistance, and is excellent in fire resistance.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, the present invention has been made of an ethylene homopolymer or a copolymer of ethylene and another α-olefin, Intrinsic viscosity has a specific range, and HRI-IZOD, which is a parameter relating to molding properties and fire resistance, is a parameter relating to melt tension and impact resistance, is HLM.
An ethylene polymer having a specific range with respect to I, and further having an α-olefin content and density in a specific range,
In hollow molding, especially large-sized hollow molding, it has excellent moldability such as uniform stretchability, high rigidity, excellent mechanical properties such as impact resistance, high melt tension, and excellent fire resistance. It has been found that an ethylene polymer composition is provided.
Furthermore, the fuel tank manufactured by the above-mentioned ethylene polymer composition has excellent impact resistance even with a thinner thickness than conventional products,
It has been found that it has fire resistance.

That is, the present invention relates to an ethylene homopolymer or an ethylene copolymer comprising ethylene and an α-olefin having 3 to 20 carbon atoms and having an α-olefin content of 10% by weight or less, (1) intrinsic viscosity [η] is 2 to 6 (dl / g); (2) density is 0.945 to 0.970 (g / cm ³ ); (3) melt tension (MT) and 21.6 kg load The relationship between the melt index (HLMI) and the high-speed impact strength (HRI-IZ) measured at MT ≧ −12.4 log HLMI + 20.5 (4) −30 ° C.
OD) and HLMI relationship, characterized in that it is a HRI-IZOD ≧ -logHLMI + 1.15, in comprising an ethylene-based polymer
Empty molded article, and resides in a fuel tank that consists therefrom.

Hereinafter, the present invention will be described in detail. The ethylene polymer of the present invention comprises an ethylene homopolymer or a copolymer with an α-olefin having 3 to 20 carbon atoms,
Those having an olefin content of 10% by weight or less, preferably 5% by weight or less are used. Examples of the α-olefin having 3 to 20 carbon atoms include propylene, butene-1, pentene-1, hexene-1, octene-1, decene-
1, octadecene-1 and 4-methylpentene-
1,3-methylbutene-1, 3-methylpentene-1,
Further, vinyl cyclohexane, styrene, and the like are included. On the other hand, if the α-olefin content is more than 10% by weight, the rigidity of the ethylene polymer decreases, which is not preferable.

The ethylene polymer of the present invention has an intrinsic viscosity [η] of 2 to 6 dl / g, preferably 2.3 to 5 dl / g.
It is necessary to be in the range of 5 dl / g, more preferably in the range of 3 to 5 dl / g. When the intrinsic viscosity is less than 2 dl / g, the mechanical strength is reduced and the drawdown resistance is poor, which is not preferable. On the other hand, if it exceeds 6 dl / g, the moldability decreases, which is not preferable. The ethylene polymer of the present invention, density of 0.970~0.945g / cm ^3, preferably 0.970~0.955g / cm ^3, more preferred more than 0.960 g / cm ³ 0.970g
/ Cm ³ or less, and more preferably an ethylene homopolymer.
If the density is less than 0.945 g / cm ³ , the rigidity decreases, which is not preferable.

The ethylene polymer of the present invention must satisfy the relation of MT ≧ HL2.4 + 0.5, preferably MT ≧ 12.4logHLMI + 23.5. If the MT is lower than the above relation, the melt tension is inferior and the fire resistance of the thinned fuel tank is inferior, which is not preferable.

The ethylene polymer of the present invention has -30
The relationship between HRI-IZOD and HLMI measured at ° C. must satisfy the relationship of HRI-IZOD ≧ −logHLMI + 1.15, preferably HRI−IZOD ≧ −logHLMI + 1.4. If the HRI-IZOD is lower than the above relationship, the impact resistance is poor, and particularly, the impact resistance of the thinned fuel tank is poor, which is not preferable. The MT and HRI-IZOD can be controlled, for example, by using a specific catalyst and polymerizing under specific conditions, or by specifying polymerization conditions in multi-stage polymerization. Next, an example of the method for producing the ethylene polymer of the present invention will be described, but the present invention is not limited to the following production method.

The ethylene polymer of the present invention can be produced by polymerizing under a specific condition using a specific catalyst or by specifying polymerization conditions in a multistage polymerization. Specific catalysts include, for example, Mg compounds, Ti compounds,
Examples thereof include a solid catalyst component (A) containing halogen as an essential component and a catalyst containing an organoaluminum compound (B) as a main component. Specifically, for example, (A) the general formula Mg
(OR ¹ ) _m X ¹² _2-m (wherein R ¹ represents an alkyl, aryl, or cycloalkyl group, X ¹ represents a halogen atom, and m is 1 or 2). and (a), the general formula _{^{Ti (oR 2) n X 2}} 4-n ( wherein R ² represents alkyl, aryl or cycloalkyl group,, X ² represents a halogen atom, n represents 4 ≧ n ≧ 1 The compound (b) represented by the following general formula (I):

[0014]

Embedded image

(Where R^Three Is alkyl, aryl or
Represents a cycloalkyl group, which may be the same or different.
p represents 20 ≧ p ≧ 2. )
Tanate (c) and optionally a compound of general formula R^Four OH (formula
Middle R^Four Represents an alkyl, aryl or cycloalkyl group
Show. Uniform carbonization containing alcoholic compound represented by)
Carbonization obtained by treating a hydrogen solution with a halogenating agent
Hydrogen-insoluble solid catalyst component and (B) organoaluminum compound
Of ethylene using a catalyst system consisting of
Polymerized or ethylene and α-olefin having 3 to 20 carbon atoms
Can be produced by copolymerization with More specific
Include Mg compounds used in the production of solid catalyst components
The general formula Mg (OR) of (a)¹ )_mX¹ _2-m(Where R¹ Is
Represents an alkyl, aryl, or cycloalkyl group;
X¹ Represents a halogen atom, and m is 1 or 2. )
Specific examples of the compound represented by¹ Is methyl,
Ethyl, propyl, butyl, pentyl, hexyl, oct
C1 such as tyl, tolyl, xylyl, cyclohexyl, etc.
Up to about 5 alkyl, aryl, cycloalkyl groups
Yes, X¹ Is chlorine, bromine, or iodine
Compounds such as dimethoxymagnesium, diethoxymag
Nesium, ethoxymagnesium chloride, dipheno
Xymagnesium and the like. M of the general formula
Is preferred. Ti compound (b)
Of the general formula Ti (OR^Two )_nX^Two _4-n(Where R ^Two Is archi
X, an aryl, or a cycloalkyl group;^Two Is
It represents a halogen atom, and n represents 4 ≧ n ≧ 1. )
As the Ti compound to be used, R^Two , X^TwoAs above R¹ ,
X¹ The above-mentioned examples are similarly mentioned. Specifically, n
Are tetraethoxytitanium, tetraprot
N = 3, such as poxy titanium, tetra n-butoxy titanium, etc.
Compounds such as triethoxymonochlorotitanium and tripro
Poxy monochlor titanium, tri n-butoxy monochlor
Compounds where n is 2, such as titanium, are diethoxydichloro.
Titanium, dipropoxydichlorotitanium, di-n-butoxy
Ethoxyt is a compound in which n is 1, such as dichlorotitanium.
Lichlortitanium, propoxytrichlorotitanium, n-butyl
Toxitrichlorotitanium and the like. Especially when n is 4
And 3 are preferred. Among them, n is a compound having 4
Tetra-n-butoxytitanium, a compound wherein n is 3
N-butoxymonochlorotitanium and the like are preferred.

The above general description of the polyalkyl titanate (c)
Compounds of the formula (I) wherein R ^Three Is alkyl, ant
Or cycloalkyl groups, which may be the same or different
May be. p represents 20 ≧ p ≧ 2. ) As before
In the general formula, R^Three Is R¹In the same way,
I can do it. Tetraethoxy titanium as a specific compound
2-20 mers of tetrapropoxy titanium
, Tetrabutoxytitanium 2-20 mer, tetrakis
(2 ethylhexyloxy) titanium 2 to 20 mer,
Examples include 2- to 20-mers of torstearyloxytitanium.
It is. Among them, 2-butameric tetrabutoxy titanium and
Dimers of tetrapropoxytitanium are preferred. Sa
In addition, a small amount of H_Two React O
Using the condensate of tetraalkoxytitanium obtained by
You can also. Also, the alcohol used as necessary
Formula R of the phenolic compound (d)^Four OH (where R^Four Is archi
Represents an aryl, aryl or cycloalkyl group. As)
Is R^Four Is R¹ The examples given in
You. Specifically, ethyl alcohol, n-propyl alcohol
, Isopropyl alcohol, n-butyl alcohol
And n-octyl alcohol.

As the solid catalyst component (A), a homogeneous hydrocarbon solution containing the Mg compound (a), the Ti compound (b), the polyalkyl titanate (c) and, if necessary, the alcohol (d) is prepared. As the hydrocarbon used as a solvent, hexane, an aliphatic hydrocarbon such as heptane,
Alicyclic hydrocarbons such as cyclohexane, and aromatic hydrocarbons such as benzene, toluene, and xylene are used. To prepare the hydrocarbon solution, a Mg compound, a Ti compound, and a polyalkyl titanate may be pre-contacted to prepare a uniform liquid, or a Mg compound and a Ti compound may be pre-contacted to form a uniform liquid. After preparation, the polyalkyl titanate may be contacted.

A homogeneous liquid can be achieved by mixing and heating the above three or two components depending on the kind of the compound to be used, but if a uniform liquid is difficult to produce, the presence of an alcohol is necessary. Is preferred. The order of addition is not particularly limited. After mixing, preferably 100 ° C to 1
By heating to 70 ° C., a uniform liquid substance or a uniform alcohol solution can be obtained. Next, a hydrocarbon solvent is added to make a hydrocarbon solution. When alcohol is used, the hydrocarbon solvent may be added after distilling off the alcohol. Alternatively, after preparing a liquid material comprising two components of a Mg compound and a Ti compound, and then adding a hydrocarbon solvent to make a uniform hydrocarbon solution, polyalkyl titanate may be added.

Then, the solid hydrocarbon component (A) is obtained by treating the homogeneous hydrocarbon solution obtained as described above with a halogenating agent. The halogenating agent is not particularly limited as long as it has a halogenating action, and usually a compound having a halogen covalently bonded thereto is used. Specifically, chlorides such as boron trichloride, titanium tetrachloride, silicon tetrachloride, tin tetrachloride, vanadium tetrachloride, and aluminum chloride; compounds containing chlorine such as hydrogen chloride, thionyl chloride and chlorosulfonic acid; or chlorine and bromine , Iodine and the like. Among them, titanium tetrachloride, silicon tetrachloride and the like are preferable.

The method of treating with these halogen-containing compounds is not particularly limited, but it is usually preferable to carry out the treatment at a temperature of normal temperature to 200 ° C. The halogenation treatment may be performed once or may be repeated twice or more. The degree of halogenation is in the range shown below with respect to the Mg compound, Ti compound, polyalkyl titanate and alcohol compound.

[0021]

(Equation 1) Is preferred. More preferably

[0022]

(Equation 2)

Range. (Where X is halogenated
X represents the number of moles of halogen atoms in the agent,¹ , X^Two , R
¹ , OR^Two , OR^Three , OR^Four In the general formula of the compound
The number of moles of each group is shown. After the solid catalyst component is obtained as described above, the solid is separated.
Release and wash with hydrocarbon solvent. And Mg compound
(A), Ti compound (b), polyalkyl titanate
The amount of each component used in (c) is a molar ratio of each component.

## EQU3 ## 0.1 ≦ (b) / (a) ≦ 5 0.3 ≦ (c) / (a) ≦ 8

## EQU4 ## It is used in the range of 0.2 ≦ (b) / (a) ≦ 2 0.5 ≦ (c) / (a) ≦ 4.

Outside the above range, the melt tension is reduced, so that the moldability such as drawdown resistance and uniform stretchability is deteriorated, and the fire resistance is lowered. Further, the impact resistance tends to be poor, which is not preferable. The alcohol compound (d) is used in an amount necessary to obtain the above-mentioned uniform liquid.

Next, the organoaluminum compound used as a cocatalyst is represented by the general formula AlR ⁵ _q (OR ⁶ ) _{r
^{X 5 3- (q + r)}} ( wherein, R ^5, R ⁶ represents alkyl, aryl, a cycloalkyl group, X ⁵ represents a halogen atom, q is a 2 to 3, r is 0-1 The compound is represented by the following formula: Specific examples include triethylaluminum, triisobutylaluminum, diethylaluminum monochloride, diisobutylaluminum monochloride, diethylaluminum monoethoxide and the like. Further, a reaction product of a trialkylaluminum and water can also be used. One of these organoaluminum compounds may be used, or two or more compounds may be used.

The proportion of the organoaluminum compound (B) used is determined by the concentration of the organoaluminum compound and the ratio between the organoaluminum compound and the solid catalyst component, ie, the product of the Al / Ti atomic ratio [Al] (mmol / l) × (Al / Ti) is used in the range of 1.2 to 0.02, preferably 1.0 to 0.03, more preferably 0.5 to 0.05. Below the above range, the polymerization activity is reduced, and above the above range, the molding processing properties such as uniform stretchability are inferior, and the melt tension is lowered, so that the fire resistance of the product is lowered. Further, the impact resistance is lowered, which is not preferable.

Polymerization of ethylene or copolymerization with the above-mentioned α-olefin is carried out using the above catalyst system, and the polymerization reaction is carried out in an inert solvent by slurry polymerization, solution polymerization, or gas phase polymerization. It is performed by As the inert solvent, aliphatic hydrocarbons such as butane, hexane and heptane, alicyclic hydrocarbons such as cyclohexane, and aromatic hydrocarbons such as benzene and toluene are used. The polymerization reaction is usually selected from the range of normal temperature to 200 ° C. and normal pressure to 100 atm. In addition, a polymer having a desired molecular weight can be easily obtained by introducing hydrogen in the polymerization reaction.

Further, in producing the ethylene polymer of the present invention, not only a single-stage polymerization method but also a multi-stage polymerization method can be employed. As an example of the multi-stage polymerization method, (a) a polymerization reaction is performed in two steps, that is, a method in which polymerization is further performed in a second reaction zone in the presence of a reaction product obtained by polymerization in a first reaction zone; (B) Ethylene homopolymerization is carried out in one of the first and second reaction zones, and a polymer A having a viscosity average molecular weight of 60,000 to 150,000 is converted into a polymer having a viscosity-average molecular weight of 6 to 150,000.
From 0% to 90% by weight, and (c) ethylene homopolymerization or α-
Copolymerization with olefin, α-olefin content 1
0% by weight or less, a polymer B having a viscosity average molecular weight of 500,000 to 4,000,000 is produced in an amount of 40% by weight to 10% by weight;
A method of polymerizing so that the molecular weight ratio of the polymer B and the polymer A is in the range of 3 to 50 is exemplified.

Further, other catalysts used in the production of the ethylene copolymer of the present invention include, for example, (A) a general formula Mg (OR ¹ ) _m X ¹² _-m (where R ¹ is an alkyl , An aryl, or a cycloalkyl group, X ¹ represents a halogen atom, and m is 1 or 2.
Compound (a), the general formula _{^{Ti (OR 2) n X 2}} 4-n ( wherein R ² represents alkyl, aryl or cycloalkyl group, X ² represents a halogen atom, n represents 4 ≧ n ≧ 1 And an alcohol (c) represented by the general formula R ⁴ OH (where R ⁴ represents an alkyl, aryl or cycloalkyl group), if necessary. A hydrocarbon-insoluble solid catalyst component obtained by treating a homogeneous hydrocarbon solution with a solution comprising titanyl chloride (TiOCl ₂ ) (d) and a halogen-containing compound (e) having no reducing ability; A catalyst system formed by combining with an aluminum compound is exemplified. More specifically, as the Mg compound (a), the Ti compound (b), and the alcohol (c) used as needed in the production of the solid catalyst component, the same compounds as those of the above-mentioned catalyst are used. You. The solid catalyst (A) is the above-mentioned Mg compound,
A homogeneous solution containing the Ti compound and optionally used alcohol is prepared. As the hydrocarbon used as the solvent, those exemplified above are used. To prepare a hydrocarbon solution, an Mg compound and a Ti compound are brought into contact in advance to prepare a uniform liquid. When it is difficult to generate a uniform liquid, it is preferable to use an alcohol. The order of addition is not particularly limited.

After mixing, the mixture is preferably heated to 100 to 170 ° C. to obtain a uniform liquid or a uniform alcohol solution. Next, a hydrocarbon solvent is added to make a hydrocarbon solution. When alcohol is used, the hydrocarbon solvent may be added after distilling off the alcohol. Next, the solid hydrocarbon component (A) is obtained by treating the homogeneous hydrocarbon solution obtained as described above with a solution comprising TiOCl ₂ and a halogen-containing compound having no reducing ability.

TiOCl_Two And halogen without reducing ability
The solution containing the compound is TiOCl_Two And reducing ability
Mixed with a halogen-containing compound
Obtained. Halogen-containing compounds without reducing ability
Although there is no particular limitation, TiOCl _Two High solubility
Compounds are preferred. Among them, titanium tetrachloride and silicon tetrachloride are preferred.
Good. Particularly, titanium tetrachloride is preferable.

Although there is no particular limitation on the method of treating with a solution containing TiOCl ₂ and a halogen-containing compound having no reducing ability, it is preferable that the solution is a uniform solution. The processing temperature is preferably from room temperature to 200 ° C. After the solid catalyst component is obtained as described above, the solid is separated and washed with a hydrocarbon solvent. Thus, Mg compound (a), Ti compound (b), TiOCl
_{2 The} amount of each component used in (d) is the molar ratio of each component.

The range is 0.01 ≦ (b) / (a) ≦ 10 0.1 ≦ (d) / (a) ≦ 50. The amount of the halogen-containing compound (c) having no reducing ability is preferably in the following range with respect to the Mg compound (a), the Ti compound (b) and the alcohol (c).

[0033]

(Equation 6)

(Where X represents the number of moles of halogen atoms in the halogen-containing compound having no reducing ability, and X ¹ , X
² , OR ¹ , OR ² and OR ⁴ represent the number of moles of each group in the general formula of the compound. Outside the above range, the molding properties such as uniform stretchability are inferior and the fire resistance is reduced due to a decrease in the melt tension. Further, the impact resistance is also poor, which is not preferable.

The amount of the alcohol (e) used is an amount necessary to obtain the above-mentioned uniform liquid. Next, as the organoaluminum compound (B) used as the co-catalyst, the same compounds as those of the above-mentioned exemplified catalyst are used. The ratio of the organoaluminum compound (B) used is determined by the concentration of the organoaluminum compound and the ratio between the organoaluminum compound (B) and the solid catalyst component, that is, the product of Al / Ti atomic ratio [Al] (mmol / l) × (Al / Ti) is 2.0
To 0.01, preferably 1.0 to 0.02.

Below the above range, the polymerization activity decreases,
Above the above range, the molding properties such as uniform stretchability are inferior, and the melt tension is reduced, resulting in reduced fire resistance of the product. Also, the impact strength is undesirably reduced. Polymerization of ethylene using the catalyst system as described above or α
-Copolymerization with an olefin is carried out, and the polymerization reaction can be carried out in the same manner as in the above polymerization examples. Further, in the present invention, not only the single-stage polymerization method but also the above-described multi-stage polymerization method can be carried out similarly.

The ethylene polymer of the present invention is excellent in molding workability such as uniform stretchability, high in rigidity, excellent in melt tension, excellent in fire resistance, and excellent in impact resistance. Have. In molding the ethylene polymer of the present invention, known additives such as fillers, pigments, light stabilizers, heat stabilizers, flame retardants, plasticizers, antistatic agents, release agents, foaming agents, and nucleating agents are used. You may mix | blend an agent.

The fuel tank of the present invention can be manufactured by a known blow molding method or the like. For example, the ethylene polymer of the present invention is passed from an extruder through a die to form the parison. The parison is produced by inflating the parison from inside by a pneumatic pressure, bringing the parison into close contact with the mold, and simultaneously cooling the parison. The ethylene-based polymer of the present invention provides a material having a curing phenomenon (strain harness).
Dening) is likely to occur, and there is a property of suppressing excessive elongation of the portion. Since the parison is blown up in a state where the deformation of the parison is uniform in the curved portion of the mold, the curved portion of the obtained molded product is obtained. Can be formed with a greater thickness than conventional ones.

When a multi-layer fuel tank is manufactured, for example, the resin composition of each layer is individually plasticized from a plurality of extruders and extruded into the same die having the same circular flow path. The thicknesses of the respective layers are made uniform and the respective layers are overlapped to form an apparently one layer of parison, which is then molded in a molding die in the same manner as described above. As the multilayer fuel tank, a three-type five-layer structure in which a high-density polyethylene layer of the ethylene-based polymer composition of the present invention is laminated on both surfaces of a barrier layer via an adhesive layer is particularly preferable. At that time, the thickness of the barrier layer is 0.01 to 0.5 mm,
Preferably, the thickness of the adhesive layer is 0.1 to 0.3 mm.
01-0.5 mm, preferably 0.3 mm, the thickness of the high density polyethylene layer is 1-10 mm, preferably 1.5
It is selected from the range of ５5 mm.

In the case of a multilayer fuel tank, it can be suitably used as a laminated fuel tank in which a polyethylene layer formed from an ethylene polymer composition is laminated on at least one side of the barrier layer via an adhesive layer. The barrier layer is made of a thermoplastic polyester resin such as polyamide resin, polyethylene terephthalate and polybutylene terephthalate, an ethylene-vinyl acetate copolymer having a saponification degree of 93% or more, preferably 96% or more and an ethylene content of 25 to 50% by mole. From a saponified ethylene-vinyl acetate copolymer.

Particularly, a polyamide resin is preferable from the viewpoints of formation stability and gas barrier properties, and a polyamide obtained by polycondensation of a diamine and a dicarboxylic acid, a polyamide obtained by condensation of an aminocarboxylic acid, a polyamide obtained from a lactam, or a polyamide obtained from these. Usually, a relative viscosity of about 1 to 6 and a melting point of 170 to 2 such as copolymerized polyamide.
80 ° C, preferably 200 to 240 ° C is used. Specifically, for example, nylon-6, nylon-6
6, Nylon-610, Nylon-9, Nylon-1
1, nylon-12, nylon-6 / 66, nylon-
66/610, nylon-6 / 11 and the like.
Particularly, nylon-6 is preferable.

In the present invention, the polyamide layer is preferably formed from a modified polyamide resin composition comprising the above polyamide resin and a maleic anhydride-modified ethylene-α-olefin copolymer. -The olefin copolymer has a crystallinity of 1
３５35%, preferably 1-30%, with a melt index of 0.01-50 g / 10 min, preferably 0.1-2 g
0 g / 10 min of ethylene-α-olefin copolymer,
Maleic anhydride is present in an amount of 0.05 to 1% by weight, preferably 0.1% by weight.
Grafted from 2 to 0.6% by weight is used. Examples of the α-olefin of the ethylene-α-olefin copolymer include propylene, butene-1, hexene-1, and the like. These α-olefins are contained in an amount of 30% by weight or less, preferably 5 to 20% by weight. Copolymerized with ethylene.

The proportion of the maleic anhydride-modified ethylene-α-olefin copolymer to be used is selected from the range of 10 to 50 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of the polyamide resin. It is used by kneading at a temperature of 280 ° C. with an extruder or the like.

As the adhesive layer, a homopolymer or copolymer of an α-olefin such as ethylene or propylene may be used in an unsaturated carboxylic acid or a derivative thereof in an amount of 0.01 to 1% by weight, preferably 0.02 to 0.6%. Modified polyolefins grafted by weight can be used. In particular, the density is 0.940-0.
Modification of 970 g / cm ³ of ethylene homopolymer or copolymer of ethylene with 3% by weight or less, preferably 0.05 to 0.5% by weight of α-olefin such as propylene, butene-1, hexene-1 Things are preferred. Examples of the unsaturated carboxylic acids or derivatives thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid and anhydrides thereof. Particularly, maleic anhydride is preferred.

[0045]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, various physical property tests were performed according to the following methods. (1) Intrinsic viscosity [η] It was measured in tetralin at 130 ° C. (2) Density Measured according to JIS K6760.

(4) Melt tension (MT) Using a “melt tension tester” manufactured by Toyo Seiki,
A sample melted at 190 ° C. was passed through an orifice having a diameter of 1 mm, a length of 5 mm and an inflow angle of 60 °, and a constant speed of 0.44 g / m
The tension at the time of extruding at in and taking out at 0.94 m / min was determined. The draft rate (take-up speed / nozzle linear speed) was 1.25. (5) Melt index (HLMI) 190 ° C based on ASTM-D-1238-57T,
It was measured at a load of 21.6 kg.

(6) High-speed impact strength (HRI-IZOD) <Preparation of sample> According to JIS K7110, width: 6.0
mm, thickness: 9.55 mm, press piece with length 63.5
mm and the notch was cut. <Measurement> Measurement was performed at −30 ° C. and 7.7 m / sec using Model GRC8250 manufactured by Dynatup. (7) Flexural stiffness (stiffness) Measured according to ASTM D747.

Example 1 (1) Preparation of Solid Catalyst Component A 3 liter flask equipped with a condenser was sufficiently dried and purged with nitrogen, and then 66.5 g of Mg (OEt) ₂ was added.
(0.58 mol), 98.7 g of Ti (OBu) ₄
(0.29 mol), the temperature was increased to 130 ° C. with stirring, and heat treatment was performed. After 4 hours, a homogeneous viscous liquid was obtained. After cooling to about 80 ° C., 1.0 liter of toluene was added to obtain a uniform solution. 2 dried and purged with nitrogen
The entire amount of the above solution was transferred to a 4 liter autoclave. To this toluene solution, 1272 g (1.31 mol) of tetrabutoxytitanium tetramer was added.
4.5 liters of toluene were added. 40 ° C under stirring
Then, 4.24 liters (38.6 mol) of TiCl ₄ was diluted with toluene to a concentration of 4.55 mol / l, and added over 3 hours. Subsequently, the temperature was raised to 105 ° C. over 30 minutes and maintained for 1 hour. Next, after cooling, it was washed with normal hexane to obtain a solid catalyst component. The Ti content in the solid catalyst component was 34.9% by weight.

(2) Preliminary polymerization of ethylene A reactor for prepolymerization having a capacity of 300 liters was charged with 220 liters of normal hexane, and then 360 g of the solid catalyst component obtained in Example 1 was introduced. 2 kg / cm of hydrogen
^After introducing ² and raising the temperature to 80 ° C., 0.36 mol of triethylaluminum was fed together with ethylene to start preliminary polymerization. Ethylene was continuously introduced, and prepolymerization was performed for 0.5 hour to obtain 10 g of polyethylene per 1 g of the solid catalyst component. After the completion of the prepolymerization, the system was cooled and washed with normal hexane.

(3) Ethylene polymerization Using a continuous polymerization apparatus equipped with a reactor having a capacity of 500 liters, ethylene 27 kg / hr and normal hexane 63
kg / hr and hydrogen were continuously supplied so as to obtain a polyethylene having an intrinsic viscosity shown in Table 1, and the prepolymerized catalyst prepared in Example 1 was supplied in an amount of 2.5 g / h.
r, and triethylaluminum were introduced at a rate of 1.5 g / hr, and ethylene was homopolymerized under the conditions of 80 ° C., a total pressure of 25 kg / cm ² , and an average residence time of 3 hours.
Polyethylene in the reactor was introduced into the degassing tank at a rate of 25 kg / hr, and polymer powder was obtained through coarse separation and drying steps. To 100 parts by weight of the obtained polyethylene, 0.1 part by weight of Irganox 1010 (trade name, manufactured by Ciba Geigy) as a hindered phenol-based stabilizer, and Irgafos 168 (trade name, manufactured by Ciba-Geigy) as a phosphite-based stabilizer ) And 0.1 part by weight of calcium stearate were added and pelletized, and subjected to various physical property tests and molding tests. The results are shown in Table 1.

(Example 2) (1) Preparation of fixed catalyst component A 3-liter flask equipped with a condenser was sufficiently dried and purged with nitrogen, and then 133 g of Mg (OEt) ₂ was added.
(1.16 mol), 197 g of Ti (OBu) ₄
(0.58 mol), the temperature was increased to 130 ° C. with stirring, and heat treatment was performed. After 4 hours, a homogeneous viscous liquid was obtained. After cooling to about 80 ° C., 1.0 liter of toluene was added to obtain a uniform solution. 2 dried and purged with nitrogen
The entire amount of the above solution was transferred to a 4 liter autoclave. To this toluene solution, 957 g (0.986 mol) of tetrabutoxytitanium tetramer was added.
5.8 liters of toluene were added. 40 ° C under stirring
1.99 liters (18.13 mol) of TiCl ₄
Was diluted with toluene to a concentration of 4.55 mol / l, and 3
Added over time. 105 ° C for 30 minutes
And kept for 1 hour. Next, after cooling, 12.5 liters of the supernatant was withdrawn by decantation,
Further, it was washed with 10 liters of toluene. afterwards,
4.0 liters of toluene was added and an additional 4.55 mol was added.
/ L concentration of TiCl ₄ / toluene solution was added again so that the amount of TiCl ₄ became 18.13 mol. Subsequently, heat treatment was carried out at 105 ° C. for 1 hour, and after cooling, washing with normal hexane was performed to obtain a fixed catalyst component. The Ti content in the solid catalyst component was 33.8% by weight.

(2) Preliminary polymerization of ethylene The same procedure as in Example 1 was carried out except that 730 g of the solid catalyst component was used and 0.52 mol of triethylaluminum was used. (3) Polymerization of ethylene Polymerization was carried out in the same manner as in Example 1 except that the above-mentioned prepolymerization catalyst was introduced at a rate of 2.5 g / hr and triethylaluminum at a rate of 1.5 g / hr. The results are shown in Table 1.

Example 3 (1) Preparation of Solid Catalyst Component A 3-liter flask equipped with a condenser was sufficiently dried and purged with nitrogen, and then 133 g of Mg (OEt) ₂ was added.
(1.16 mol), 197 g of Ti (OBu) ₄
(0.58 mol), the temperature was increased to 130 ° C. with stirring, and heat treatment was performed. After 4 hours, a homogeneous viscous liquid was obtained. After cooling to about 80 ° C., 1.0 liter of toluene was added to obtain a uniform solution. 2 dried and purged with nitrogen
The entire amount of the above solution was transferred to a 4-liter autoclave. To this solution was added 5.89 liters of toluene. Next, TiOCl ₂ prepared in advance
(0.99 mol) and a warm solution of TiCl ₄ (11.6 mol) was added over 3 hours. Subsequently, the temperature was raised to 105 ° C. over 30 minutes and maintained for 1 hour.
Thereafter, the mixture was cooled and washed with normal hexane to obtain a solid catalyst component. The Ti content in the solid catalyst component was 33.5% by weight.

(2) Preliminary polymerization of ethylene The same procedure as in Example 1 was carried out except that 730 g of the solid catalyst component was used and 0.52 mol of triethylaluminum was used. (3) Polymerization of ethylene The above prepolymerized catalyst was introduced at a rate of 2.5 g / hr and triethylaluminum at a rate of 1.75 g / hr, and hydrogen and butene-1 had intrinsic viscosity and density shown in Table-1. Polymerization was carried out in the same manner as in Example 1 except that polyethylene was continuously supplied so as to obtain polyethylene. The results are shown in Table 1.

Example 4 (1) Preparation of Solid Catalyst Component The amount of tetrabutoxytitanium tetramer used was reduced to 844.
g (0.87 mol), except that the solid catalyst component was prepared in the same manner as in Example 1. The Ti content in the solid catalyst component was 31.2% by weight. (2) Preliminary polymerization of ethylene It was carried out in the same manner as in Example 1.

(3) Polymerization of Ethylene Using the same continuous polymerization apparatus as in Example 1, ethylene 27
kg / hr, normal hexane 63 kg / hr, and hydrogen were continuously supplied so as to obtain a polyethylene having the intrinsic viscosity shown below, 1.7 g / hr of the prepolymerization catalyst component, and 1 g of triethylaluminum. Introduced at a rate of 0.75 g / hr, 90 ° C., total pressure 25
The polymerization was carried out under the condition of kg / cm ² and the viscosity average molecular weight was 1
20,000 ethylene homopolymers were polymerized at 75% by weight of the total polymer. The polyethylene in the reactor was led to a degassing tank at a predetermined speed, and after separating hydrogen, it was led to a 500-liter capacity second-stage reactor. In the second stage reactor, ethylene 9kg / h
r, normal hexane 21 kg / hr was continuously supplied, and polymerization was carried out at 50 ° C. for an average residence time of 1.5 hours. A second-stage ethylene homopolymer having a viscosity average molecular weight of 1.3 million was polymerized at 25% by weight of the whole polymer. did. After the completion of the reaction, the viscosity average molecular weight of the polymer was measured to be 340,000. The following operations were performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 Polymerization of Ethylene Polymerization was carried out in the same manner as in Example 1 except that the prepolymerized catalyst prepared in Example 1 was introduced at a rate of 1.3 g / hr, and triethylaluminum was introduced at a rate of 5.3 g / hr. did. Table-Results
It is shown in FIG.

[0058] (Comparative Example 2) (1) sufficiently dried 24 l autoclave equipped with a preparation condenser of the solid catalyst component, after nitrogen substitution, Mg (OEt) ₂ 133
g (1.16 mol) and 160 parts of Ti (OBu) ₃ Cl.
g (0.53 mol) and Zr (OBu) ₃ Cl
g (0.40 mol), the temperature was increased to 130 ° C. with stirring, and heat treatment was performed. After 4 hours, a homogeneous viscous liquid was obtained. After cooling to about 80 ° C., 3.5 liters of toluene was added to obtain a uniform solution. Then, at 40 ° C., EtAl
210 g of Cl ₂ are added over 1.5 hours and the remaining E
490 g of tAlCl ₂ was added over 1.5 hours.
After stirring at 80 ° C. for 2 hours, the mixture was cooled and washed with normal hexane to obtain a solid catalyst component. Ti in solid catalyst component
The content was 10.1% by weight.

(2) Ethylene polymerization Using a continuous polymerization apparatus equipped with a reactor having a capacity of 500 liters, ethylene 13 kg / hr and normal hexane 32
kg / hr and hydrogen are continuously supplied so as to obtain a polyethylene having an intrinsic viscosity shown below, and the solid catalyst component is supplied at a rate of 1.7 g / hr and triethylaluminum at a rate of 4.4 g / hr. Introduce 9
Polymerization was carried out under the conditions of 0 ° C. and a total pressure of 25 kg / cm ² , and an ethylene homopolymer having a viscosity average molecular weight of 60,000 was converted into 6
0% by weight was polymerized. The polyethylene in the reactor was led to a degassing tank at a predetermined speed, and after separating hydrogen, it was led to a 500-liter capacity second-stage reactor. 11 kg / hr of ethylene and 21 kg / hr of normal hexane were continuously supplied to the second-stage reactor, polymerized at 50 ° C., and a second-stage enrene homopolymer having a viscosity-average molecular weight of 640,000 was converted into a total weight. It polymerized by 40% by weight. After the completion of the reaction, the viscosity average molecular weight of the polymer was measured and found to be 270,000. The following operation is performed in Example 1.
The same was done. The results are shown in Table 1.

(Comparative Example 3) The same as Example 1 except that triethylaluminum was introduced at a rate of 1.65 g / hr during the polymerization of ethylene, and the amount of hydrogen was changed so as to obtain the intrinsic viscosity shown in Table 1. Polymerized. The results are shown in Table 1.

Comparative Example 4 A commercially available ethylene polymer ("SHOLEX 4551H" manufactured by Showa Denko KK) was used.

[0062]

[Table 1]

Example 5 and Comparative Example 5 Each of the HDPEs produced in Examples and Comparative Examples shown in Table 1 was melted in an extruder (cylinder set temperature; 185 to 215 ° C.), and a die (die temperature) was obtained. 235 ° C.) and a diameter of 530
mm parison was formed. The drawdown is adjusted by a parison controller so that the parison thickness immediately before molding is constant in the injection direction.
Saddle type with 40R corners. Temperature; 20 ° C.), and after injecting air (pressure: 6 kg / cm ² ), a 60-liter fuel tank (product weight: 7 kg and 10 kg) was obtained at a product take-out temperature of 80 ° C.

For each of the obtained fuel tanks, a drop test and the thickness of the 40R corner were measured. Table-
It is shown in FIG. The drop impact strength was evaluated by filling the fuel tank with antifreeze and dropping it at -40 ° C from a height of 16 m to check for cracks. Further, in Example 5-1, the thickness of the 40R corner portion was 2.2 m.
m, the product weight is 5.9kg
Thus, a fuel tank reduced in weight by 1.1 kg per product was obtained. When the drop impact strength of the fuel tank was measured, no damage was observed. Further, the product take-out temperature can be reduced by 12 ° C. in the same cooling time, and the cooling time per product can be reduced by about 24 seconds.

[0065]

[Table 2]

(Example 6) The HDPE produced in the examples shown in Table 3 and the raw material resins for the respective layers of the adhesive resin (a) and the barrier resin (b) shown below were individually used using separate extruders. The mixture was melted, extruded into the same die having a concentric flow path, and the respective layers were superposed and co-extruded in a die (in-die temperature: 230 ° C.) to form a parison having a diameter of 530 mm. Thereafter, in the same manner as in Example 5, a 60-liter capacity multi-layer (three types and five layers) fuel tank (7 kg) was obtained. No damage was observed in the container in the drop impact strength test of the container. The thickness of the 40R corner was measured to be 2.9 m.
m.

[0067]

[Table 3] Table-3 層 Layer structure Resin used Thickness (μm) ───────── ──────────────── Outer layer Example 1 2600 Adhesive layer (A) APO 100 barrier layer (B) MPA 100 adhesive layer (A) APO 100 inner layer Example 1 2600 ─ ────────────────────────

(A) Modified polyethylene (APO) Modified polyethylene obtained by grafting maleic anhydride (0.4% by weight) to high-density polyethylene having a density of 0.960 g / cm ³ . Melt index (MI); 0.1 g / 1
0 minutes. (B) Modified polyamide resin composition (MPA) 80 parts by weight of nylon-6 having a relative viscosity of 4.0 and 20% by weight of maleic anhydride (0.3% by weight) modified ethylene-butene-1 copolymer (ethylene ~ Butene-1 (13 mol
%) The copolymer has a crystallinity of 20% and an MI of 3.5 g / 1.
0 min).

[0069]

According to the present invention, uniform stretchability is excellent,
Since use of the high rigidity and and ethylene polymer having excellent mechanical properties such as impact resistance, have a excellent impact strength at thinner thickness than conventionally, excellent fire resistance, light fuel tank is obtained. Further, the cooling time and the injection time can be shortened, and the production of a fuel tank with a shortened production cycle can be realized.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-2-155906 (JP, A) JP-A-2-132109 (JP, A) JP-A-5-117321 (JP, A) JP-A-1- 292009 (JP, A) JP-A-63-154753 (JP, A) JP-A-5-84809 (JP, A) JP-A-4-47918 (JP, A) JP-B-57-2579 (JP, B1) (58) Field surveyed (Int.Cl. ⁷ , DB name) C08F 10/00-10/14 C08F 110/00-110/14 C08F 210/00-210/18 B65D 1/02 B60K 15/03

Claims (7)

(57) [Claims] 1. An ethylene homopolymer or an ethylene copolymer comprising ethylene and an α-olefin having 3 to 20 carbon atoms and having an α-olefin content of 10% by weight or less, Viscosity [η] is 2 to 6 (dl / g) (2) Density is 0.945 to 0.970 (g / cm ³ ) (3) Melt tension (MT) and melt index (HLMI) at 21.6 kg load MT ≧ −12.4 log HLMI + 20.5 (4) High-speed impact strength (HRI-IZ) measured at −30 ° C.
Hollow OD) and HLMI relationship is, of ethylene based polymer, which is a HRI-IZOD ≧ -logHLMI + 1.15
Molded products . 2. A fuel tank comprising a hollow molded product comprising the ethylene polymer according to claim 1. 3. The fuel tank according to claim 2 , wherein the hollow molded article comprises a laminate having a barrier layer and a polyethylene layer comprising the ethylene-based polymer according to claim 1. 4. A laminate comprising a barrier layer and a polyethylene layer comprising the ethylene-based polymer according to claim 1, which is present on at least one side of the laminate via an adhesive layer. The fuel tank according to claim 3 . 5. The fuel tank according to claim 3 , wherein the barrier layer is made of a polyamide resin. 6. The polyamide resin has a crystallinity of 1 to 35.
%, Ethylene having a melt index of 0.01 to 50%
Maleic anhydride is added to α-olefin copolymer at 0.05 to
1% by weight grafted maleic anhydride-modified ethylene to α
The fuel tank according to claim 5 , wherein the fuel tank is formed from a composition of an olefin copolymer and a polyamide resin. 7. The fuel tank according to claim 4, wherein the adhesive layer is obtained by graft-modifying high-density polyethylene with 0.01 to 1% by weight of an unsaturated carboxylic acid or a derivative thereof.