JP2010242055A - Non-crosslinked extruded foaming sheet made of polyethylene-based resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-crosslinked extruded foaming sheet made of a polyethylene-based resin with sufficient processability, excellent in heat-resistance stability and tear-resistance. <P>SOLUTION: The non-crosslinked extruded foaming sheet made of the polyethylene based resin includes an appearance density of 30-200 g/L and a closed cell ratio of 70% or more. The non-vulcanized extruded foaming sheet made of the polyethylene based resin is characterized in that the density of the polyethylene based resin composition constituting an extrusion foaming sheet is 935-970 kg/m<SP>3</SP>, the Charpy impact strength at -25°C is 3.0 KJ/m<SP>2</SP>or more and the flexural modulus is 400 MPa or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a non-crosslinked extruded foam sheet made of polyethylene resin.

Conventionally, foams of polyethylene resins have been used in a wide range of applications by taking advantage of their excellent buffering properties, heat insulation properties, cutting workability, flexibility, resilience and the like. For example, if it is a sheet-like material, it is a packaging material for precision equipment, a heat insulating mat for a bathroom, if it is a rod-like material, a joint material that fills the gaps in the building, if it is a board-like material, a beat plate, cutting processing If it is, it has been applied to buffer pads for large electrical equipment.
Among the polyethylene-based resins having such characteristics, low-density polyethylene has a long chain branch having an appropriate length in its molecular chain, so that the melt viscosity during melting is relatively high due to the entanglement between the molecular chains. high. Also, the change in crystallinity near the melting point is more gradual than other ethylene resins. For this reason, although it is necessary to adjust the temperature within a narrow temperature range near the melting point, low density polyethylene can be foamed relatively easily as compared with other ethylene resins.

On the other hand, high-density polyethylene has a very low melt viscosity at the time of melting because its molecular chain has few branches, and also has a high crystallinity and a high crystallization speed. For this reason, it is necessary to adjust the melt viscosity suitable for foaming, and it has been difficult to produce a foamed molded article having a high closed cell ratio by foaming high-density polyethylene.
It is necessary to increase the melt tension of high-density linear polyethylene as a method of obtaining high-quality linear polyethylene with high density and high-foamed molded articles with high expansion ratio using high-density linear polyethylene. There is.

As a method for increasing the melt tension of linear polyethylene having a high density, specifically, (1) a method of mixing high molecular weight polyethylene having a high melt tension (for example, see Patent Document 1), (2) chromium-based polyethylene A method of mixing polyethylene having a high melt tension produced by a catalyst (for example, see Patent Document 2), (3) a method of mixing low density polyethylene produced by a high-pressure radical polymerization method (for example, see Patent Document 3), (4) A method of increasing the melt tension by adding a crosslinking agent or peroxide to polyethylene and modifying it (see, for example, Patent Document 4) has been proposed.
Further, in order to give a higher melt tension than the above-described method, (5) a method using special long-chain branched high-density polyethylene (for example, see Patent Document 5 and Patent Document 6), (6) Melting A study focusing on a die swell, which is one of the indices of elastic properties (for example, see Patent Document 7) has also been proposed.

Japanese Patent Laid-Open No. 10-7726 JP-A-2-132109 Japanese Unexamined Patent Publication No. 7-134359 JP 2003-327757 A JP 2006-96910 A JP 2008-222818 A JP 2005-290329 A

L.A. UTRACKI, translated by Toshio Nishi, “Polymer Alloy and Polymer Blend”, Tokyo Chemical Doujin, 1st Edition, December 6, 1991, p. 75

  The problem to be solved by the present invention is to provide a non-crosslinked extruded foam sheet made of a polyethylene resin, which has good processability, excellent heat stability and tear resistance.

As a result of intensive studies to solve the above problems, the present inventors have found that a non-crosslinked extruded foam sheet made of a polyethylene resin composition having specific physical properties can be adapted to the purpose. Based on this finding, the present invention has been made.
That is, the present invention relates to a non-crosslinked extruded foam sheet made of polyethylene resin.

  The non-crosslinked extruded foam sheet made of polyethylene resin of the present invention has good processability, and is excellent in heat resistance stability and tear resistance.

Hereinafter, the present invention will be specifically described.
The non-crosslinked extruded foam sheet made of polyethylene resin of the present embodiment has an apparent density of 30 g / L to 200 g / L, a closed cell ratio of 70% or more, and the density of the polyethylene resin composition constituting the extruded foam sheet Is 935 to 970 kg / m ³ , the Charpy impact strength at −25 ° C. is 3.0 KJ / m ² or more, and the flexural modulus is 400 MPa or more.
Furthermore, the polyethylene resin composition constituting the polyethylene resin non-crosslinked extruded foam sheet of the present embodiment is a linear polyethylene (A) 90 that satisfies the following requirements (a-1) to (a-4): It is preferable to include 10 to 60% by mass of the branched high-pressure method low-density polyethylene (B) that satisfies the requirements (b-1) to (b-2) below.
The polyethylene resin composition constituting the polyethylene resin non-crosslinked extruded foam sheet preferably has a melt flow rate of 0.1 to 20 g / 10 min at 190 ° C. and a load of 2.16 kg, at 190 ° C. The melt tension is preferably 15 mN or more.

(A-1) An ethylene homopolymer or a copolymer comprising an ethylene unit and one or more α-olefin units having 3 to 20 carbon atoms.
(A-2) The density is 935 to 975 kg / m ³ .
(A-3) The melt flow rate at 190 ° C. and a load of 2.16 kg is 0.1 to 20 g / 10 min.
(A-4) Mw / Mn calculated | required by the gel permeation chromatography method is 3-7. (Mn is the number average molecular weight, Mw is the weight average molecular weight, and Mw / Mn is the molecular weight distribution.)

(B-1) The density is 910 to 930 kg / m ³ .
(B-2) The melt flow rate at 190 ° C. and a load of 2.16 kg is 0.1 to 10 g / 10 min.
(B-3) The melt tension at 190 ° C. is 20 mN or more.

(Linear polyethylene (A))
The linear polyethylene (A) used in the polyethylene resin composition constituting the non-crosslinked extruded foam sheet made of polyethylene resin according to the present embodiment is an ethylene homopolymer or an ethylene unit and one or more carbon numbers. It is a copolymer composed of 3 to 20 α-olefin units.
Examples of the α-olefin having 3 to 20 carbon atoms to be copolymerized with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene and 1-hexadecene. 1-octadecene, 1-eicocene, 3-methyl-1-butene, 4-methyl-1-pentene, 6-methyl-1-heptene and the like. As the α-olefin, 1-butene, 1-hexene and 1-octene are preferable because they are generally easily available, and 1-butene is preferable in consideration of the polymerization process.

The copolymer may be a copolymer of ethylene and one kind of α-olefin, or may be a copolymer of ethylene and an α-olefin obtained by combining two or more kinds. The linear polyethylene (A) may be a copolymer obtained by dry blending or melt blending an ethylene / α-olefin copolymer and a copolymer of ethylene and another α-olefin at an arbitrary ratio. Good.
The density of the linear polyethylene (A) is 935 to 975 kg / m ³ . The density of the linear polyethylene (A) is preferably 935 to 965 kg / m ³ , more preferably 945 to 960 kg / m ³ .
When the density of the linear polyethylene (A) is 935 kg / m ³ or more, the mechanical properties are excellent when a non-crosslinked extruded foam sheet made of polyethylene resin is used. If the density of the linear polyethylene (A) is 975 kg / m ³ or less, when it is a non-crosslinked extruded foam sheet made of polyethylene resin, it is possible to achieve both excellent mechanical properties and good buffering properties.

The density of the linear polyethylene (A) is preferably within the above range in terms of being able to achieve both good mechanical properties as well as good buffering properties when a non-crosslinked extruded foam sheet made of polyethylene resin is used. .
The melt flow rate of the linear polyethylene (A) (hereinafter sometimes referred to as “MFR”) is 0.1 to 20 g / 10 min at 190 ° C. and a load of 2.16 kg. The MFR of the linear polyethylene (A) is preferably 1 to 15 g / 10 minutes, more preferably 5 to 10 g / 10 minutes.
When the MFR of the linear polyethylene (A) is 0.1 g / 10 min or more and 20 g / 10 min or less, the moldability of the polyethylene resin non-crosslinked extruded foam sheet is excellent.
The molecular weight distribution (Mw / Mn) of the linear polyethylene (A) is determined by gel permeation chromatography and is 3 to 7, preferably 3 to 6. Here, Mn is a number average molecular weight, and Mw indicates a weight average molecular weight.

If the molecular weight distribution of the linear polyethylene (A) is within the above range, due to the uniformity of the molecular weight, the processability is good, the foamed state is good, and the mechanical properties and heat stability are excellent. A non-crosslinked extruded foam sheet made of polyethylene resin can be obtained.
In particular, if the molecular weight distribution of the linear polyethylene (A) is 7 or less, a conventional Ziegler-Natta catalyst is used in the blend of the linear polyethylene (A) and the branched high-pressure method low density polyethylene (B). Unlike the case of the polymerized ethylene homopolymer or the copolymer of ethylene and α-olefin, the compatibility between the linear polyethylene (A) and the branched high-pressure low-density polyethylene (B) can be made. It is presumed that it is possible to suppress phase separation of both crystal states. For this reason, it is possible to obtain a non-crosslinked extruded foam sheet made of a polyethylene resin, which has good processability, a good foamed state, and excellent mechanical properties, heat resistance stability, buffer properties, and tear resistance.

In the present embodiment, the molecular weight distribution can be obtained by a gel permeation chromatography method.
Specifically, Waters 150-C ALC / GPC apparatus, Shodex AT-807S and Tosoh TSK-gelGMH-H6 are used in series as a column, and trichlorobenzene containing 10 ppm Irganox 1010 as a solvent is used. The molecular weight distribution measured at 140 ° C. can be measured.

The linear polyethylene (A) of the present invention is an ethylene homopolymer or a copolymer of ethylene and an α-olefin and has a narrow molecular weight distribution Mw / Mn of 3-7. For this reason, it is guessed that the subject of the present invention is achieved when the molecular weight becomes uniform.
Although the manufacturing method of linear polyethylene (A) is not specifically limited, It can manufacture with the method as described below.

  As a production method of the linear polyethylene (A), there is a method of producing a polyolefin by single-stage polymerization of an α-olefin. The catalyst used in this polymerization is composed of a solid catalyst [A] and an organometallic compound [B], and the solid catalyst [A] is soluble in an inert hydrocarbon solvent represented by the following general formula 1 The carrier (A-1) prepared by reacting the compound (a-1) with the chlorinating agent (a-2) represented by the following general formula 2 is reacted with alcohol (A-2), Prepared by reacting an organometallic compound (A-3) represented by the following general formula 3 and then supporting a titanium compound (A-4) represented by the following general formula 4, The polyolefin characterized in that the metal compound [B] belongs to the group consisting of an organoaluminum compound represented by the following general formula 5 and an organomagnesium compound soluble in an inert hydrocarbon solvent represented by the following general formula 6 Manufacturing method.

(M ¹ ) _α (Mg) _β (R ¹ ) _a (R ² ) _b (OR ³ ) _c Formula 1
(In the formula, M ¹ is a metal atom other than magnesium belonging to the group consisting of Group 1, Group 2, Group 12 and Group 13 of the Periodic Table, and R ¹ , R ² and R ³ are each a carbon number. 2 or more and 20 or less, and α, β, a, b, and c are real numbers that satisfy the following relationship: 0 ≦ α, 0 <β, 0 ≦ a, 0 ≦ b, 0 <c, 0 <a + b, 0 <c / (α + β) ≦ 2, kα + 2β = a + b + c (where k is the valence of M ¹ ))

H _d SiCl _e R ⁴ _{(4- (d + e))} Equation 2
(Wherein R ⁴ is a hydrocarbon group having 1 to 12 carbon atoms, and d and e are numbers satisfying the following relationship: 1 ≦ d, 1 ≦ e, 2 ≦ d + e ≦ 4)

M ² R ⁵ _f Q _(h−f) Formula 3
(Wherein M ² is a metal atom belonging to Groups I to III of the Periodic Table, R ⁵ is a hydrocarbon group having 1 to 20 carbon atoms, and Q is OR ⁶ , OSiR ⁷ R ⁸ R ⁹ , NR ¹⁰ R. ¹¹ , SR ¹² and a group belonging to the group consisting of halogen, R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² are hydrogen atoms or hydrocarbon groups, and f is greater than 0 A real number and h is the valence of M ² )

Ti (OR ¹³ ) _i X _(4-i) Equation 4
(In the formula, i is a real number of 0 or more and 4 or less, R ¹³ is a hydrocarbon group of 1 to 20 carbon atoms, and X is a halogen atom.)

R ¹⁴ _(3-j) AlQ ′ _j Formula 5
(Wherein R ¹⁴ is a hydrocarbon group having 1 to 12 carbon atoms, Q ′ is a group belonging to the group consisting of a hydrogen atom, a halogen atom, and OR ¹⁵ , and R ¹⁵ is a group having 1 to 20 carbon atoms. And j is a real number of 0 or more and 2 or less)

(M ³ ) _γ (Mg) _δ (R ¹⁵ ) _m (R ¹⁶ ) _n.
(In the formula, M ³ is a metal atom other than magnesium belonging to the group consisting of Group 1, Group 2, Group 12 and Group 13 of the Periodic Table, and R ¹⁵ and R ¹⁶ each have 2 to 20 carbon atoms. The following hydrocarbon groups, where γ, δ, m, and n are real numbers that satisfy the following relationship: 0 ≦ γ, 0 <δ, 0 ≦ k, 0 ≦ m, pγ + 2δ = m + n (where p is M Valence of ³ ))

Next, the solid catalyst [A] in the present invention will be described.
In the present invention, the solid catalyst [A] is an organomagnesium compound (a-1) soluble in an inert hydrocarbon solvent represented by the following general formula 1 and a chlorinating agent represented by the following general formula 2. The carrier (A-1) prepared by the reaction with (a-2) is reacted with alcohol (A-2), and then the organoaluminum compound (A-3) represented by the following general formula 3 is reacted. Next, it is prepared by supporting a titanium compound (A-4) represented by the following general formula 4.

(M ¹ ) _α (Mg) _β (R ¹ ) _a (R ² ) _b (OR ³ ) _c Formula 1
(In the formula, M ¹ is a metal atom other than magnesium belonging to the group consisting of Group 1, Group 2, Group 12 and Group 13 of the Periodic Table, and R ¹ , R ² and R ³ are each a carbon number. 2 or more and 20 or less, and α, β, a, b, and c are real numbers that satisfy the following relationship: 0 ≦ α, 0 <β, 0 ≦ a, 0 ≦ b, 0 <c, 0 <a + b, 0 <c / (α + β) ≦ 2, kα + 2β = a + b + c (where k is the valence of M ¹ ))

H _d SiCl _e R ⁴ _{(4- (d + e))} Equation 2
(Wherein R ⁴ is a hydrocarbon group having 1 to 12 carbon atoms, and d and e are numbers satisfying the following relationship: 1 ≦ d, 1 ≦ e, 2 ≦ d + e ≦ 4)

M ² R ⁵ _f Q _(h−f) Formula 3
(Wherein M ² is a metal atom belonging to Groups I to III of the Periodic Table, R ⁵ is a hydrocarbon group having 1 to 20 carbon atoms, and Q is OR ⁶ , OSiR ⁷ R ⁸ R ⁹ , NR ¹⁰ R. ¹¹ , SR ¹² and a group belonging to the group consisting of halogen, R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² are hydrogen atoms or hydrocarbon groups, and f is greater than 0 A real number and h is the valence of M ² )

Ti (OR ¹³ ) _i X _(4-i) Equation 4
(In the formula, i is a real number of 0 or more and 4 or less, R ¹³ is a hydrocarbon group of 1 to 20 carbon atoms, and X is a halogen atom.)

  Next, the inert hydrocarbon solvent in the present invention will be described. The inert hydrocarbon solvent in the present invention is an aliphatic hydrocarbon compound such as pentane, hexane or heptane, an aromatic hydrocarbon compound such as benzene or toluene, or an alicyclic hydrocarbon compound such as cyclohexane or methylcyclohexane. An aliphatic hydrocarbon is preferable.

Next, the organomagnesium compound that is soluble in the inert hydrocarbon solvent represented by Formula 1 in the present invention will be described. This organomagnesium compound is shown as a complex form of organomagnesium soluble in an inert hydrocarbon solvent, but encompasses all dihydrocarbylmagnesium compounds and complexes of this compound with other metal compounds It is. The relational expression kα + 2β = a + b + c of the symbols α, β, a, b, c indicates the stoichiometry between the valence of the metal atom and the substituent.
In the general formula 1, the hydrocarbon group represented by R ¹ to R ² is an alkyl group, a cycloalkyl group or an aryl group, and examples thereof include methyl, ethyl, propyl, butyl, propyl, hexyl, octyl, decyl, Examples thereof include cyclohexyl and phenyl groups, and preferably R ¹ to R ² are alkyl groups. When α> 0, as the metal atom M ¹ , a metal element belonging to Groups I to III of the periodic table can be used, and examples thereof include lithium, sodium, potassium, beryllium, zinc, boron, and aluminum. However, aluminum, boron, beryllium, and zinc are particularly preferable.

The ratio β / α of magnesium to the metal atom M ¹ can be arbitrarily set, but is preferably in the range of 0.1 to 30, particularly 0.5 to 10. Further, when a certain organomagnesium compound in which α = 0 is used, for example, when R ¹ is 1-methylpropyl or the like, it is soluble in an inert hydrocarbon solvent, and such a compound is also used in the present invention. Gives favorable results. In the general formula (M ¹ ) _α (Mg) _β (R ¹ ) _a (R ² ) _b (OR ³ ) _c , R ¹ and R ² when α = 0 are the following three groups (1), It is recommended that it is any one group of (2) and (3).

(1) At least one of R ¹ and R ² is a secondary or tertiary alkyl group having 4 to 6 carbon atoms, preferably both R ¹ and R ² have 4 to 6 carbon atoms, At least one is a secondary or tertiary alkyl group.
(2) R ¹ and R ² are alkyl groups having different carbon atoms, preferably R ¹ is an alkyl group having 2 or 3 carbon atoms, and R ¹ is an alkyl having 4 or more carbon atoms. Be a group.
(3) At least one of R ¹ and R ² is a hydrocarbon group having 6 or more carbon atoms, preferably an alkyl group that becomes 12 or more when the number of carbon atoms contained in R ¹ and R ² is added. .

  These groups are specifically shown below. The secondary or tertiary alkyl group having 4 to 6 carbon atoms in (1) includes 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, 2-methylbutyl, 2-ethylpropyl, 2 , 2-dimethylpropyl, 2-methylpentyl, 2-ethylbutyl, 2,2-dimethylbutyl, 2-methyl-2-ethylpropyl group and the like are used, and 1-methylpropyl group is particularly preferable. Next, in (2), examples of the alkyl group having 2 or 3 carbon atoms include ethyl, 1-methylethyl, propyl and the like, and an ethyl group is particularly preferable. Examples of the alkyl group having 4 or more carbon atoms include butyl, pentyl, hexyl, heptyl, octyl group and the like, and butyl and hexyl groups are particularly preferable.

  Furthermore, examples of the hydrocarbon group having 6 or more carbon atoms in (3) include hexyl, heptyl, octyl, nonyl, decyl, phenyl, 2-naphthyl group and the like. Among the hydrocarbon groups, an alkyl group is preferable, and among the alkyl groups, hexyl and octyl groups are particularly preferable. In general, an increase in the number of carbon atoms contained in an alkyl group facilitates dissolution in an inert hydrocarbon solvent. However, the use of an unnecessarily long alkyl group is not preferred in terms of handling because the solution viscosity increases. The organomagnesium compound is used as an inert hydrocarbon solution, but it can be used as long as a trace amount of Lewis basic compounds such as ethers, esters, and amines are contained or remain in the solution.

Next, the alkoxy group (OR ³ ) will be described. The hydrocarbon group represented by R ³ is preferably an alkyl group or aryl group having 1 to 12 carbon atoms, and particularly preferably an alkyl group or aryl group having 3 to 10 carbon atoms. Specifically, for example, methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 1,1-dimethylethyl, pentyl, hexyl, 2-methylpentyl, 2-ethylbutyl, 2-ethylpentyl, Examples include 2-ethylhexyl, 2-ethyl-4-methylpentyl, 2-propylheptyl, 2-ethyl-5-methyloctyl, octyl, nonyl, decyl, phenyl, naphthyl groups, and the like. Butyl, 1-methylpropyl, 2 -Methylpentyl and 2-ethylhexyl groups are particularly preferred.

These organomagnesium compounds include organomagnesium compounds belonging to the group consisting of general formulas R ¹ MgX and R ¹ ₂ Mg (R ¹ is as defined above and X is halogen), and general formula M ¹ R ² _k And an organometallic compound belonging to the group consisting of M ¹ R ² _(k−1) H (M ¹ , R ² , k are as defined above) in an inert hydrocarbon solvent at room temperature to 150 ° C. An alkoxymagnesium compound having a hydrocarbon group represented by R ³ that is soluble in an alcohol having an hydrocarbon group represented by R ³ or an inert hydrocarbon solvent, if necessary, and the like. It is synthesized by the method of reacting.

  Among these, when reacting an organomagnesium compound soluble in an inert hydrocarbon solvent with an alcohol, the order of the reaction is such that the alcohol is added to the organomagnesium compound, or the organomagnesium compound is added to the alcohol. Any method can be used, or a method of adding both at the same time. In the present invention, the reaction ratio of the organomagnesium compound soluble in the inert hydrocarbon solvent and the alcohol is not particularly limited. The range of the molar composition ratio c / (α + β) is 0 ≦ c / (α + β) ≦ 2, and 0 ≦ c / (α + β) <1 is particularly preferable.

Next, the chlorinating agent in the present invention will be described.
In the present invention, the chlorinating agent used when synthesizing (A-1) is represented by the following general formula 2, and at least one is a silicon chloride compound having a Si—H bond.

H _d SiCl _e R ⁴ _{(4- (d + e))} Formula 2
(Wherein R ⁴ is a hydrocarbon group having 1 to 12 carbon atoms, and d and e are numbers satisfying the following relationship: 1 ≦ d, 1 ≦ e, 2 ≦ d + e ≦ 4)

In the above formula 2, the hydrocarbon group represented by R ⁴ is an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, for example, methyl, ethyl, propyl, 1-methylethyl , Butyl, pentyl, hexyl, octyl, decyl, cyclohexyl, phenyl group, and the like, preferably an alkyl group having 1 to 10 carbon atoms, and having 1 to 3 carbon atoms such as methyl, ethyl, propyl, 1-methylethyl group, etc. Are particularly preferred. D and e are one or more real numbers satisfying the relationship of 2 ≦ d + e ≦ 4, and e is particularly preferably 2 or more.

These compounds include HSiCl ₃ , HSiCl ₂ CH ₃ , HSiCl ₂ C ₂ H ₅ , HSiCl ₂ C ₃ H ₇ , HSiCl ₂ (1-CH ₃ C ₂ H ₅ ), HSiCl ₂ C ₄ H ₉ , HSiCl _{2 C 6 H 5, HSiCl 2 (} 4-Cl-C 6 H 4), HSiCl 2 CH = CH 2, HSiCl 2 CH 2 C 6 H 5, HSiCl 2 (1-C 10 H 7), HSiCl 2 CH 2 CH = CH ₂ , H ₂ SiClCH ₃ , H ₂ SiClC ₂ H ₅ , HSiCl (CH ₃ ) ₂ , HSiCl (C ₂ H ₅ ) ₂ , HSiClCH ₃ (1-CH ₃ C ₂ H ₅ ), HSiClCH ₃ (C _{6 H 5), HSiCl (C 6} H 5) 2 and the like, of two or more selected from these compounds or their compounds Silicon chloride compounds are used consisting of compounds. As the silicon chloride compound, trichlorosilane, monomethyldichlorosilane, dimethylchlorosilane, and ethyldichlorosilane are preferable, and trichlorosilane and monomethyldichlorosilane are particularly preferable.

  Next, the reaction between the organomagnesium compound and the chlorinating agent in the present invention will be described. In the present invention, in the reaction of the organomagnesium compound and the chlorinating agent, a chlorinating agent is previously added as a reaction solvent body, for example, a chlorine such as an inert hydrocarbon solvent, 1,2-dichloroethane, o-dichlorobenzene, dichloromethane, etc. It is preferably used after diluting with a hydrofluoric hydrocarbon, an ether-based medium such as diethyl ether or tetrahydrofuran, or a mixed medium thereof. In particular, in view of the performance of the catalyst, an inert hydrocarbon solvent is preferable. In the present invention, the reaction temperature is not particularly limited, but is preferably carried out at a temperature not lower than the boiling point of the silicon chloride compound used as a chlorinating agent or not lower than 40 ° C. for the progress of the reaction. Although there is no restriction | limiting in particular also in the reaction ratio of an organomagnesium compound and a silicon chloride compound, Usually, it is 0.01-100 mol of silicon chloride compounds with respect to 1 mol of organomagnesium compounds, Preferably, with respect to 1 mol of organomagnesium compounds, It is the range of 0.1-10 mol of silicon chloride compounds.

  With respect to the reaction method in the present invention, a method of simultaneous addition in which an organomagnesium compound and a silicon chloride compound are simultaneously introduced into the reactor, and a reaction is performed, and after the silicon chloride compound is charged in the reactor in advance, the organomagnesium compound is added to the reactor. There is a method of introducing or a method of introducing an organomagnesium compound into the reactor in advance and then introducing a silicon chloride compound into the reactor. However, the organomagnesium compound is introduced into the reactor after the silicon chloride compound is introduced into the reactor in advance. The method of introducing into is preferable. The solid component obtained by the above reaction is preferably separated by filtration or decantation, and then sufficiently washed with an inert hydrocarbon solvent to remove unreacted products or by-products.

In the present invention, the reaction between the organomagnesium compound and the silicon chloride compound can be performed in the presence of a solid. This solid may be either an inorganic solid or an organic solid, but it is preferable to use an inorganic solid. The following are mentioned as an inorganic solid.
(I) Inorganic oxide (ii) Inorganic carbonate, silicate, sulfate (iii) Inorganic hydroxide (iv) Inorganic halide (v) Double salt, solid solution or mixture of (i) to (iv)

Specific examples of the inorganic solid include silica, alumina, silica / alumina, hydrated alumina, magnesia, tria, titania, zirconia, calcium phosphate, barium sulfate, calcium sulfate, magnesium silicate, magnesium / calcium, aluminum silicate [(Mg / Ca ) O · Al ₂ O ₃ · 5SiO ₂ · nH ₂ O], potassium silicate · aluminum [K ₂ O · 3Al ₂ O ₃ · 6SiO ₂ · 2H ₂ O], magnesium iron silicate [(Mg · Fe) ₂ SiO ₄ ], Aluminum silicate [Al ₂ O ₃ · SiO ₂ ], calcium carbonate, magnesium chloride, magnesium iodide, and the like, and particularly preferred are silica, silica / alumina and magnesium chloride. The specific surface area of the inorganic solid is preferably 20 m ² / g or more, particularly preferably 90 m ² / g or more.

  Next, alcohol (A-2) in this invention is demonstrated. In the present invention, the alcohol (A-2) is preferably a saturated or unsaturated alcohol having 1 to 20 carbon atoms. Such alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 1-pentanol, 1-pentanol, Examples include hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, cyclohexanol, phenol, cresol, and the like, and linear alcohols having 3 to 8 carbon atoms are particularly preferable. It is also possible to use a mixture of these alcohols.

  In the present invention, the amount of alcohol (A-2) to be used is not particularly limited, but it is preferably more than 0.05 and 10 or less in terms of a molar ratio with respect to magnesium atoms contained in the carrier (A-1). 0.1 to 1 is more preferable, and 0.2 to 0.5 is more preferable. When the amount of alcohol (A-2) used is greater than 0.05 in terms of the molar ratio to the magnesium atom contained in the support (A-1), the Si-containing component contained in the catalyst support is efficiently removed. This is preferable because the catalytic properties are improved. Moreover, when the usage-amount of alcohol (A-2) is 10 or less by the molar ratio with respect to the magnesium atom contained in a support | carrier (A-1), an excess alcohol remains in a catalyst, and catalyst characteristics are obtained. This is preferable because the phenomenon of lowering can be suppressed. Furthermore, when the amount of alcohol (A-2) used is 0.2 or more and 0.5 or less in terms of a molar ratio to the magnesium atom contained in the carrier (A-1), the catalyst characteristics are improved. This is preferable because an appropriate amount of alcohol remains in the catalyst. The reaction of the carrier (A-1) and the alcohol (A-2) can be carried out in the presence or absence of an inert hydrocarbon solvent. Although there is no restriction | limiting in particular in the temperature at the time of reaction, It is preferable to implement in 25 to 200 degreeC.

Next, the organometallic compound (A-3) in the present invention will be described.
In the present invention, the organometallic compound (A-3) is represented by the following general formula 3.

M ² R ⁵ _f Q _(h−f) Formula 3
(Wherein M ² is a metal atom belonging to Groups I to III of the Periodic Table, R ⁵ is a hydrocarbon group having 1 to 20 carbon atoms, and Q is OR ⁶ , OSiR ⁷ R ⁸ R ⁹ , NR ¹⁰ R. ¹¹ , SR ¹² and a group belonging to the group consisting of halogen, R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² are hydrogen atoms or hydrocarbon groups, and f is greater than 0 A real number and h is the valence of M ² )

In the present invention, M ² is a metal atom belonging to Groups I to III of the Periodic Table, and examples thereof include lithium, sodium, potassium, beryllium, magnesium, boron, and aluminum. Particularly preferred. The hydrocarbon group represented by R ⁵ is an alkyl group, a cycloalkyl group or an aryl group, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, a cyclohexyl group and a phenyl group. Is an alkyl group.
Q represents a group belonging to the group consisting of OR ⁶ , OSiR ⁷ R ⁸ R ⁹ , NR ¹⁰ R ¹¹ , SR ¹² and halogen, and R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² Is a hydrogen atom or a hydrocarbon group, and Q is particularly preferably a halogen.

  Examples of the organometallic compound (A-3) in the present invention include methyllithium, butyllithium, methylmagnesium chloride, methylmagnesium bromide, methylmagnesium iodide, ethylmagnesium chloride, ethylmagnesium bromide, ethylmagnesium iodide, butylmagnesium. Chloride, butylmagnesium bromide, butylmagnesium iodide, dibutylmagnesium, dihexylmagnesium, triethylboron, trimethylaluminum, dimethylaluminum bromide, dimethylaluminum chloride, dimethylaluminum methoxide, methylaluminum dichloride, methylaluminum sesquichloride, triethylaluminum, diethylaluminum Chloride, diethylaluminum Romido, diethylaluminum ethoxide, ethylaluminum dichloride, ethylaluminum sesquichloride, tripropylaluminum, tributylaluminum, tri (2-methylpropyl) aluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, etc., organic aluminum Compounds are particularly preferred. It is also possible to use a mixture of these compounds.

  In the present invention, the amount of the organometallic compound (A-3) used is not particularly limited, but is preferably 0.01 times or more and 20 times or less in terms of a molar ratio with respect to the alcohol (A-2). It is more preferably 1 to 10 times, and further preferably 0.5 to 2.5 times. If the amount of the organometallic compound (A-3) used is 0.01 times or more in terms of the molar ratio to the alcohol (A-2), excess alcohol can be efficiently removed, and organic If the usage-amount of a metal compound (A-3) is 20 times or less by the molar ratio with respect to alcohol (A-2), an organometallic compound (A-3) will be an organometallic compound (A-3) in a catalyst manufacturing process. Does not adversely affect the subsequent steps of the reaction. Furthermore, if the amount of the organometallic compound (A-3) used is 0.5 to 2.5 times the molar ratio to the alcohol (A-2), the alcohol necessary for improving the catalyst characteristics Can be left in the catalyst. In the present invention, the molar ratio to the magnesium atom contained in the carrier (A-1) is preferably 0.01 to 20 times, more preferably 0.1 to 10 times. . Although there is no restriction | limiting in particular about the temperature of reaction, The range which is 25 degreeC or more and 200 degrees C or less and less than the boiling point of a reaction medium is preferable.

Next, the titanium compound (A-4) in the present invention will be described.
In the present invention, a titanium compound represented by the following general formula 4 is used as the titanium compound (A-4).

Ti (OR ¹³ ) _i X _(4-i) Equation 4
(In the formula, i is a real number of 0 or more and 4 or less, R ¹³ is a hydrocarbon group of 1 to 20 carbon atoms, and X is a halogen atom.)

Examples of the hydrocarbon group represented by R ¹³ include aliphatic hydrocarbon groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, 2-ethylhexyl, heptyl, octyl, decyl, and allyl groups, cyclohexyl, and 2-methylcyclohexyl. , An alicyclic hydrocarbon group such as cyclopentyl group, and an aromatic hydrocarbon group such as phenyl and naphthyl group. An aliphatic hydrocarbon group is preferable. Examples of the halogen atom represented by X include chlorine, bromine and iodine, with chlorine being preferred. Specifically, titanium tetrachloride is preferable. Two or more kinds of titanium compounds (A-4) selected from the above can be mixed and used.

In the present invention, the amount of the titanium compound (A-4) used is not particularly limited, but the amount supported on the carrier (A-1) is the molar ratio to the magnesium atom contained in the carrier (A-1). 0.01 or more and 20 or less are preferable, and 0.05 or more and 10 or less are particularly preferable. If the amount of the titanium compound (A-4) supported on the carrier (A-1) is too small, the polymerization activity per catalyst is low, and if it is too large, the polymerization activity per titanium tends to be low. If the amount of the titanium compound (A-4) supported on the carrier (A-1) is 0.01 or more in terms of the molar ratio to the magnesium atom contained in the carrier (A-1), the polymerization activity per catalyst is sufficiently high. If it is high and 20 or less, the polymerization activity per titanium is sufficiently high. In the present invention, the reaction temperature during the loading is not particularly limited, but it is preferably carried out in the range of 25 ° C. or more and 150 ° C. or less.
In the present invention, when the titanium compound (A-4) is supported, it is preferably supported by reacting the titanium compound (A-4) with the organometallic compound (A-5). This organometallic compound (A-5) is a compound represented by the aforementioned general formula 3, and may be the same as or different from the aforementioned organometallic compound (A-3).

M ² R ⁵ _f Q _(h−f) Formula 3
(Wherein M ² is a metal atom belonging to Groups I to III of the Periodic Table, R ⁵ is a hydrocarbon group having 1 to 20 carbon atoms, and Q is OR ⁶ , OSiR ⁷ R ⁸ R ⁹ , NR ¹⁰ R. ¹¹ , SR ¹² and a group belonging to the group consisting of halogen, R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² are hydrogen atoms or hydrocarbon groups, and f is greater than 0 A real number and h is the valence of M ² )

In the present invention, M ² is a metal atom belonging to Groups I to III of the Periodic Table, and examples thereof include lithium, sodium, potassium, beryllium, magnesium, boron, and aluminum. Particularly preferred. The hydrocarbon group represented by R ⁵ is an alkyl group, a cycloalkyl group or an aryl group, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, a cyclohexyl group and a phenyl group. Is an alkyl group.
Q represents a group belonging to the group consisting of OR ⁶ , OSiR ⁷ R ⁸ R ⁹ , NR ¹⁰ R ¹¹ , SR ¹² and halogen, and R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² Is a hydrogen atom or a hydrocarbon group, and Q is particularly preferably a halogen.

  Examples of the organometallic compound (A-3) in the present invention include methyllithium, butyllithium, methylmagnesium chloride, methylmagnesium bromide, methylmagnesium iodide, ethylmagnesium chloride, ethylmagnesium bromide, ethylmagnesium iodide, butylmagnesium. Chloride, butylmagnesium bromide, butylmagnesium iodide, dibutylmagnesium, dihexylmagnesium, triethylboron, trimethylaluminum, dimethylaluminum bromide, dimethylaluminum chloride, dimethylaluminum methoxide, methylaluminum dichloride, methylaluminum sesquichloride, triethylaluminum, diethylaluminum Chloride, diethylaluminum Romido, diethylaluminum ethoxide, ethylaluminum dichloride, ethylaluminum sesquichloride, tripropylaluminum, tributylaluminum, tri (2-methylpropyl) aluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, etc., organic aluminum Compounds are particularly preferred. It is also possible to use a mixture of these compounds.

The order of the reaction between (A-4) and (A-5) is not particularly limited, and (A-5) is added following (A-4). Following (A-5), (A- Any method of adding 4) and adding (A-4) and (A-5) at the same time is possible, and (A-4) is preferably added following (A-4). The molar ratio of (A-5) to (A-4) is preferably 0.1 to 10, particularly preferably 0.5 to 5. The reaction between (A-2) and (A-5) is carried out in an inert hydrocarbon solvent, but it is preferable to use an aliphatic hydrocarbon solvent such as hexane or heptane.
Although there is no restriction | limiting in particular about the temperature of reaction, The range which is 25 degreeC or more and 200 degrees C or less and less than the boiling point of a reaction medium is preferable.

Next, the organoaluminum compound [B] in the present invention will be described.
The organoaluminum compound in the present invention is represented by the following general formula 5.

R ¹⁴ _(3-j) AlQ ′ _j Formula 5
(Wherein R ¹⁴ is a hydrocarbon group having 1 to 12 carbon atoms, Q ′ is a group belonging to the group consisting of a hydrogen atom, a halogen atom, and OR ¹⁵ , and R ¹⁵ is a group having 1 to 20 carbon atoms. And j is a real number of 0 or more and 2 or less)

Examples of R ¹⁴ include methyl, ethyl, propyl, butyl, 2-methylpropyl, pentyl, 3-methylbutyl, hexyl, octyl, decyl, phenyl, tolyl, and the like. Of these, an ethyl group and a 2-methylpropyl group are particularly preferable. Two or more kinds of these hydrocarbon groups may be contained. h is preferably 0.05 or more and 1.5 or less, and particularly preferably 0.1 or more and 1.2 or less.
Next, the organomagnesium compound in the present invention is represented by the following general formula 6.

(M ³ ) _γ (Mg) _δ (R ¹⁵ ) _m (R ¹⁶ ) _n.
(In the formula, M ³ is a metal atom other than magnesium belonging to the group consisting of Group 1, Group 2, Group 12 and Group 13 of the Periodic Table, and R ¹⁵ and R ²¹⁶ each have 2 to 20 carbon atoms. The following hydrocarbon groups, where γ, δ, m, and n are real numbers that satisfy the following relationship: 0 ≦ γ, 0 <δ, 0 ≦ k, 0 ≦ m, pγ + 2δ = m + n (where p is M Valence of ³ ))

This organomagnesium compound is shown as a complex form of organomagnesium soluble in an inert hydrocarbon solvent, but encompasses all dihydrocarbylmagnesium compounds and complexes of this compound with other metal compounds It is. The relationship between the symbols γ, δ, m and n, pγ + 2δ = m + n, indicates the stoichiometry between the valence of the metal atom and the substituent.
In the general formula 6, the hydrocarbon group represented by R ¹⁵ and R ¹⁶ is an alkyl group, a cycloalkyl group or an aryl group, and examples thereof include methyl, ethyl, propyl, butyl, propyl, hexyl, octyl, decyl, cyclohexyl, phenyl and the like, and is preferably ^{R 15} and ^{R 16} alkyl groups. When γ> 0, as the metal atom M ³ , a metal element belonging to Groups I to III of the periodic table can be used, and examples thereof include lithium, sodium, potassium, beryllium, zinc, boron, and aluminum. However, aluminum, boron, beryllium, and zinc are particularly preferable.

In the present invention, the ratio δ / γ of magnesium to the metal atom M ³ is not particularly limited, but is preferably 0.1 or more and 30 or less, and more preferably 0.5 or more and 10 or less. In addition, when an organomagnesium compound in which γ = 0 is used, for example, when R ¹⁵ is 1-methylpropyl or the like, it is soluble in an inert hydrocarbon solvent, and such a compound also has preferable results in the present invention. give. In the above general formula 6, it is recommended that R ¹⁵ and R ¹⁶ when γ = 0 is one of the following three groups (1), (2) and (3): .

(1) At least one of R ¹⁵ and R ¹⁶ is a secondary or tertiary alkyl group having 4 to 6 carbon atoms, preferably both R ¹⁵ and R ¹⁶ have 4 to 6 carbon atoms. Yes, and at least one is a secondary or tertiary alkyl group.
(2) R ¹⁵ and R ¹⁶ are alkyl groups having different carbon atoms, preferably R ¹⁵ is an alkyl group having 2 or 3 carbon atoms, and R ¹⁶ is an alkyl group having 4 or more carbon atoms. Be a group.
(3) At least one of R ¹⁵ and R ¹⁶ is a hydrocarbon group having 6 or more carbon atoms, preferably an alkyl group that becomes 12 or more when the number of carbon atoms contained in R ¹⁵ and R ¹⁶ is added. .

  These groups are specifically shown below. Examples of the secondary or tertiary alkyl group having 4 to 6 carbon atoms in (1) include 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, 2-methylbutyl, 2-ethylpropyl, 2,2-dimethylpropyl, 2-methylpentyl, 2-ethylbutyl, 2,2-dimethylbutyl, 2-methyl-2-ethylpropyl group and the like are used, and 1-methylpropyl group is particularly preferable.

Next, examples of the alkyl group having 2 or 3 carbon atoms in (2) include ethyl, 1-methylethyl, propyl and the like, and an ethyl group is particularly preferable. Examples of the alkyl group having 4 or more carbon atoms include butyl, pentyl, hexyl, heptyl, octyl group and the like, and butyl and hexyl groups are particularly preferable.
Furthermore, examples of the hydrocarbon group having 6 or more carbon atoms in (3) include hexyl, heptyl, octyl, nonyl, decyl, phenyl, 2-naphthyl group and the like. Among the hydrocarbon groups, an alkyl group is preferable, and among the alkyl groups, hexyl and octyl groups are particularly preferable. In general, an increase in the number of carbon atoms contained in an alkyl group facilitates dissolution in an inert hydrocarbon solvent. However, the use of an unnecessarily long alkyl group is not preferred in terms of handling because the solution viscosity increases. The organomagnesium compound is used as an inert hydrocarbon solution, but it can be used as long as a trace amount of Lewis basic compounds such as ethers, esters, and amines are contained or remain in the solution.

These organomagnesium compounds include an organomagnesium compound belonging to the group consisting of the general formulas R ¹⁵ MgX and R ¹⁵ ₂ Mg (R ¹⁵ is as defined above, X is halogen), and the general formula M ³ R ¹⁶ _k And an organometallic compound belonging to the group consisting of M ³ R ¹⁶ _(k-1) H (M ³ , R ¹⁶ , k are as defined above) in an inert hydrocarbon solvent at a temperature of 25 ° C. to 150 ° C. It is synthesized by the method of reacting between them.
The catalyst thus obtained is characterized by a high activity per titanium and a very high activity per catalyst, especially for the polymerization of ethylene and the copolymerization of ethylene and an α-olefin having 3 or more carbon atoms.
As the polymerization solvent, an inert hydrocarbon solvent usually used for slurry polymerization is used. The polymerization temperature is from room temperature to 120 ° C., and preferably from 50 ° C. to 100 ° C. The polymerization pressure is carried out in the range of normal pressure to 10 MPa. The molecular weight of the resulting polymer can be adjusted by changing the concentration of hydrogen present in the polymerization system, changing the polymerization temperature, or changing the concentration of the organometallic compound [B].

  In the present invention, the polyolefin production process is not particularly limited, and can be applied to any commonly used production method such as a solution method, a high-pressure method, a high-pressure bulk method, a gas method, and a slurry method. For example, the polymerization pressure is from 0.1 MPa to 200 MPa as the gauge pressure, the polymerization temperature is from 25 ° C. to 250 ° C., and propane, butane, isobutane, hexane, cyclohexane or the like is used as the solvent.

(Branched high-pressure low-density polyethylene (B))
The branched high-pressure low-density polyethylene (B) used in the polyethylene resin composition constituting the non-crosslinked extruded foam sheet made of polyethylene resin according to the present embodiment is an ethylene homopolymer or ethylene unit and one or two kinds. It is preferable that it is a copolymer with the said C3-C20 alpha olefin unit, and can be obtained by a well-known high-pressure radical polymerization method.
The density of the branched high pressure method low density polyethylene (B) is 910 to 930 kg / m ³ , preferably 915 to 928 kg / m ³ .
The MFR of the branched high-pressure method low density polyethylene (B) is 0.1 to 10 g / 10 minutes, and preferably 1.0 to 5 g / 10 minutes.
The melt tension of the branched high-pressure method low-density polyethylene (B) is 20 mN or more at 190 ° C., preferably 100 mN or more, more preferably 150 mN or more.

The melt tension of the polyethylene resin composition can be measured by the method described in the following examples.
By using the branched high-pressure polyethylene (B) having such characteristics, it is possible to bring a good effect on the processability of the non-crosslinked extruded foam sheet made of polyethylene resin.
The branched high-pressure method low-density polyethylene (B) may be a copolymer with other α-olefin, vinyl acetate, acrylate ester or the like as long as the object of the present invention is not impaired.

The polyethylene resin composition in the present embodiment is a copolymer in which the linear polyethylene (A) is composed of an ethylene homopolymer or an ethylene unit and one or two or more α-olefin units having 3 to 20 carbon atoms. It is preferable that the molecular weight distribution (Mw / Mn) is as narrow as 3-7. By blending such a linear polyethylene (A) with a branched high-pressure low-density polyethylene (B), the processability can be improved, and at the same time, the foamed state is good, and the heat stability and tear resistance are improved. It is possible to obtain a non-crosslinked extruded foam sheet made of polyethylene resin that has both properties.
In general, a blend system of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) is incompatible, and the crystal state of both phase separates (for example, see Non-Patent Document 1). In a composition obtained by blending HDPE) and low density polyethylene (LDPE), there is a concern about the foamed state during processing.

  However, in the present embodiment, the linear polyethylene (A) having a molecular weight distribution Mw / Mn as narrow as 3 to 7 and having a relatively uniform molecular weight, and the branched high-pressure method low-density polyethylene (B) When polymer blending is performed within a predetermined ratio range, there is a tendency that the crystallization speed increases and the crystal size decreases and the crystal state becomes uniform, and linear polyethylene (A) and branched high pressure method low density polyethylene ( It is suggested that B) is co-crystallized. Along with such a phenomenon, a tendency to improve the foaming state during processing is recognized. These tendencies are remarkable when the blend amount of the branched high-pressure low-density polyethylene (B) is about 15 to 25% by mass with the linear polyethylene (A) as the base resin.

The blending ratio of the linear polyethylene (A) and the branched high pressure method low density polyethylene (B) in the polyethylene resin composition is 90 to 40% by mass of the linear polyethylene (A), and the branched high pressure method low density system. Polyethylene (B) is 10 to 60% by mass, preferably linear polyethylene (A) is 90 to 60% by mass, branched high-pressure method low density polyethylene (B) is 10 to 40% by mass, and more preferably linear. -Like polyethylene (A) 85-75 mass%. The branched high-pressure method low-density polyethylene (B) is 15 to 25% by mass.
If the blended amount of the branched high-pressure method low-density polyethylene (B) is 10% by mass or more and 60% by mass or less, a non-crosslinked extruded foam sheet made of polyethylene resin having excellent processability and good foaming state is obtained. It is done.

The density of the polyethylene resin composition is preferably 935~970kg / ^{m 3,} more preferably from 935~965kg / ^{m 3,} more preferably from 945~960kg / ^{m 3.}
If the density of a polyethylene-type resin composition is 935 kg / m < ³ > or more, when it is set as the non-crosslinked extruded foam sheet made from a polyethylene-type resin, it will be excellent in a mechanical characteristic. If the density of the polyethylene resin composition is 970 kg / m ³ or less, a non-crosslinked extruded foam sheet made of polyethylene resin having excellent mechanical properties and good buffering properties can be obtained.
The density of the polyethylene resin composition is preferably within the above range in that it can be a non-crosslinked extruded foam sheet made of polyethylene resin having excellent mechanical properties and good buffering properties.

The MFR of the polyethylene resin composition is preferably 0.1 to 20 g / 10 minutes, more preferably 2.0 to 10 g / 10 minutes, and still more preferably 4.0 to 8.0 g / 10 minutes. is there.
When the MFR of the polyethylene resin composition is 0.1 g / 10 min or more and 20 g / 10 min or less, the moldability of the polyethylene resin non-crosslinked extruded foam sheet is excellent.
The melt tension of the polyethylene resin composition is 15 mN or more at 190 ° C., preferably 20 mN or more, and more preferably 50 mN or more.
The melt tension of the polyethylene resin composition is preferably 15 mN or more at 190 ° C. If it is 15 mN or more, the foaming state at the time of processing of the non-crosslinked extruded foam sheet made of polyethylene resin is also good, and a tendency to be controlled to a predetermined foaming ratio is noticeable.

Generally, when Ziegler catalyst-based linear polyethylene and branched high-pressure low-density polyethylene are mixed, they are incompatible and the crystalline state of both phase separates, so the melt tension is 15-50 mN. In such a case, it is impossible to obtain a non-crosslinked extruded foam sheet made of polyethylene resin in a good foamed state.
On the other hand, this embodiment has a melt tension of 15 to 50 mN, for example, obtained by blending the linear polyethylene (A) having the above specific physical properties with the branched high-pressure method low density polyethylene (B). By using a polyethylene-based resin composition having a degree, a non-crosslinked extruded foam sheet made of polyethylene-based resin having a good foamed state can be obtained. This is considered to be due to the fact that the polyethylene resin composition becomes uniform because the molecular weight distribution (Mw / Mn) of the linear polyethylene (A) is as narrow as 3-7.

The Charpy impact strength based on the polyethylene resin composition constituting the non-crosslinked extruded foam sheet made of polyethylene resin is preferably 3.0 KJ / m ² or more at −25 ° C., more preferably 5.0 KJ. / M ² or more.
If Charpy impact strength based on polyethylene resin composition is 3.0 KJ / m ² or more, breakage / cracking when polyethylene resin non-crosslinked extruded foam sheet is used as packaging material for frozen food And low temperature impact resistance.
The flexural modulus based on the polyethylene resin composition constituting the non-crosslinked extruded foam sheet made of polyethylene resin is preferably 400 MPa or more, more preferably 500 MPa or more. Moreover, it is preferable that it is 1500 MPa or less, More preferably, it is 1000 MPa or less.

When the flexural modulus based on the polyethylene resin composition is 400 MPa or more, the mechanical properties are excellent when a non-crosslinked extruded foam sheet made of polyethylene resin is used. On the other hand, if it is 1500 Mpa or less, when it is set as the non-crosslinked extruded foam sheet made of polyethylene resin, it is possible to achieve both excellent mechanical properties and good buffering properties.
The flexural modulus based on the polyethylene resin composition is preferably within the above range in that it can be a non-crosslinked extruded foam sheet made of polyethylene resin having excellent mechanical properties and good buffering properties.

  Antistatic agents used by adding to the polyethylene resin composition constituting the non-crosslinked extruded foam sheet made of polyethylene resin according to the present embodiment include ethylene glycol, diethylene glycol, glycerin, trimethylolpropane, pentaerythrit, sorbit Organic fatty acids such as polyhydric alcohols such as lauric acid, palmitic acid and stearic acid, or unsaturated fatty acids such as oleic acid and linoleic acid, fatty acid esters obtained by esterifying polyethylene glycol with fatty acids, or higher alcohols. Esters such as esters of higher alcohols obtained by reacting with acids or acid anhydrides; sulfate esters of higher alcohols such as lauryl alcohol and sperm alcohol, sulfate esters such as sodium dodecylbenzenesulfonate Salts and sulfate sulfonates; Phosphate esters obtained by reaction of higher alcohols with anhydrous phosphoric acid or phosphorus oxychloride; Amines such as polyoxyethylene alkylamines; Polyamide resins, polyamidoamines, alkyldiethanolamides, etc. Examples include amides; quaternary ammonium salts such as lauryltrimethylammonium chloride; betaines; amino acids; ethylene oxide adducts and the like. Among these, glycerin fatty acid ester, polyglycerin fatty acid ester, polyoxyethylene alkylamine, alkyldiethanolamide and combinations thereof are preferable.

It is preferable to contain 5-30 mass% of the antistatic agent contained in a polyethylene-type resin composition, More preferably, it is 7-20 mass%, Most preferably, it is 10-15 weight.
When the amount of the antistatic agent contained in the polyethylene resin composition is 5% by mass or more, the antistatic performance is excellent when a non-crosslinked extruded foam sheet made of polyethylene resin is used. If it is 30 weight or less, it can reduce that the antistatic agent bleeds out from the surface of the non-crosslinked extruded foam sheet made of polyethylene resin, together with excellent antistatic performance.
In the polyethylene resin composition constituting the non-crosslinked extruded foam sheet made of polyethylene resin, known additives can be added as necessary within the range not impairing the object of the present invention. Phenol stabilizers, organic phosphite stabilizers, organic thioether stabilizers, stabilizers as metal salts of higher fatty acids, organic or inorganic pigments, UV absorbers, dyes, nucleating agents, lubricants, carbon black, talc, Examples include inorganic fillers such as glass fibers or reinforcing materials, flame retardants, compounding agents added to polyolefins such as neutron blocking agents, and the like.

  Examples of the phenol-based stabilizer include 2,6-di-t-butyl-4-methylphenol, 2,6-dicyclohexyl-4-methylphenol, 2,6-diisopropyl-4-ethylphenol, 2,6- Di-t-amyl-4-methylphenol, 2,6-di-t-octyl-4-n-propylphenol, 2,6-dicyclohexyl-4-n-octylphenol, 2-isopropyl-4-methyl-6- t-butylphenol, 2-t-butyl-2-ethyl-6-t-octylphenol, 2-isobutyl-4-ethyl-6-t-hexylphenol, 2-cyclohexyl-4-n-butyl-6-isopropylphenol, Tetrakis (methylene (3,5-di-t-butyl-4-hydroxy) hydrocinnamate) methane, 2,2-methyle Bis (4-methyl-6-tert-butylphenol), 4,4-butylidenebis (3-methyl-6-tert-butylphenol), 4,4-thiobis (3-methyl-6-tert-butylphenol), 2,2 -Thiobis (4-methyl-6-tert-butylphenol), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxyphenyl) benzylbenzene, 3,5-tris (2-methyl-4-hydroxy-5-tert-butylphenol) methane, tetrakis (methylene (3,5-di-butyl-4-hydroxyphenyl) propionate) methane, β- (3,5- Di-t-butyl-4-hydroxylphenol) propionic acid alkyl ester, 2,2-oxamide bis (ethyl-3- (3,5-di-t-butyl-4-hydride) Loxyphenyl) propionate, tetrakis (methylene (2,4-di-t-butyl-4-hydroxyl) propionate), n-octadecyl-3- (4-hydroxy-3,5-di-t-butylphenyl) propionate, 2,6-di-t-butyl-p-cresol, 2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzylthiono-1,3,5-triazine, 2,2 -Methylenebis (4-methyl-6-tert-butylphenol), 4,4-methylenebis (2,6-di-tert-butylphenol), 2,2-methylenebis (6- (1-methylcyclohexyl) -p-cresol) Bis (3,5-bis (4-hydroxy-3-tert-butylphenyl) butyric acid) glycol ester, 4,4-butylidenebis (6-tert-butyl) Ru-m-cresol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-tris (2,6-dimethyl-3-hydroxy-) 4-t-butylbenzyl) isocyanurate, 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanate, 1,3,5-tris ((3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxyethyl) isocyanurate, 2 -Octylthio-4,6-di (4-hydroxy-3,5-di-t-butyl) phenoxy-1,3,5-triazine, 4,4-thiobis (6-t-butyl-m-cresol), etc. Raised It is.

  Examples of organic phosphite stabilizers include trioctyl phosphite, trilauryl phosphite, tridecyl phosphite, octyl-diphosphite, tris (2,4-di-t-butylphenyl) phosphite, triphenyl phosphite. , Tris (butoxyethyl) phosphite, tris (nonylphenyl) phosphite, distearyl pentaerythritol diphosphite, tetra (tridecyl) -1,1,3-tris (2-methyl-5-tert-butyl-4- Hydroxyphenyl) butanediphosphite, tetra (tridecyl) -4,4-butylidenebis (3-methyl-6-tert-butylphenol) diphosphite, tris (3,5-di-tert-butyl-4-hydroxyphenyl) phosphite , Tris (mono or dinonylphenyl) Phosphite, hydrogenated-4,4-isopropylidenediphenol polyphosphide, bis (octylphenyl) bis (4,4-butylidenebis (3-methyl-6-tert-butylphenol)) 1,6-hexaneol diphos Phosphide, phenyl-4,4-isopropylidenediphenol pentaerythritol diphosphide, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphide, bis (2,6-di-tert-butyl-4) -Methylphenyl) pentaerythritol diphosphide, tris ((4,4, -isopropylidenebis (2-t-butylphenol)) phosphide, di (nonylphenyl) pentaerythritol diphosphide, tris (1,3-di- Stearoyloxyisopropyl) phosphite, 4,4- Sopropylidenebis (2-t-butylphenol) di (nonylphenyl) phosphide, 9,10-di-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, tetrakis (2,4-di-) t-butylphenyl) -4,4-biphenylene diphosphide and the like.

Organic thioester stabilizers include dialkylthiopropionates such as dilauryl-, dimyristyl-, distearyl- and polyhydric alcohols of alkylthiopropionic acids such as butyl-, octyl-, lauryl-, stearyl- (for example, glycerin, Esters of trimethylolethane, trimethylolpropane, pentaerythritol, trishydroxyethyl isocyanurate), specifically, dilauryl thiopropionate, dimyristyl thiopropionate, distearyl thiodipropionate, Examples include lauryl stearyl thiodipropionate, distearyl thiodibutyrate, and pentaerythritol tetralauryl thiopropionate.
Stabilizers as metal salts of higher fatty acids include, for example, alkalis such as magnesium, calcium, and barium salts of higher fatty acids such as stearic acid, oleic acid, lauric acid, caprylic acid, arachidic acid, palmitic acid, and behenic acid. Earth metal salts, cadmium salts, zinc salts, lead salts, sodium salts, potassium salts, lithium salts, and the like are used.

  As stabilizers as metal salts of higher fatty acids, specifically, magnesium stearate, magnesium laurate, magnesium palmitate, calcium stearate calcate, barium stearate, barium laurate, barium laurate, magnesium, Zinc stearate, zinc oleate, zinc stearate, zinc laurate, lithium stearate, sodium stearate, sodium palmitate, sodium laurate, potassium stearate, potassium laurate, and calcium 12-hydroxystearate It is done.

The non-crosslinked extruded foam sheet made of polyethylene resin of the present embodiment has an apparent density of 30 g / L to 200 g / L. Preferably they are 50 g / L-150 g / L, More preferably, they are 80 g / L-120 g / L.
When the apparent density is 30 g / L or more, the mechanical properties are excellent when a non-crosslinked extruded foam sheet made of polyethylene resin is used. If it is 200 g / L or less, a non-crosslinked extruded foam sheet made of polyethylene resin having excellent mechanical properties and good buffering properties can be obtained.
The non-crosslinked extruded foam sheet made of polyethylene resin of the present embodiment has a closed cell ratio of 70% or more. Preferably it is 80% or more, More preferably, it is 90% or more.
When the closed cell ratio is 70% or more, the buffer property is excellent when a non-crosslinked extruded foam sheet made of polyethylene resin is used.

The non-crosslinked extruded foam sheet made of polyethylene resin of the present embodiment preferably has a surface resistivity of 1.0 × 10 ^{8 to} 1.0 × 10 ¹⁴ Ω, more preferably 1.0 × 10 ^{9 to} 5.0. × 10 ¹³ Ω, more preferably 1.0 × 10 ^{9 to} 1.0 × 10 ¹³ Ω.
The non-crosslinked extruded foam sheet made of polyethylene resin preferably has a thickness of 0.3 to 50 mm, more preferably 1 to 40 mm, and still more preferably 1 to 30 mm.
If thickness is 0.3 mm or more, when it is set as the non-crosslinked extrusion foaming sheet made from a polyethylene-type resin, it will be excellent in buffering property. If it is 50 mm or less, the non-crosslinked extruded foam sheet made of polyethylene resin having excellent mechanical properties as well as excellent buffering properties can be obtained.
The density of the polyethylene resin composition is preferably within the above range in that it can be a non-crosslinked extruded foam sheet made of polyethylene resin having excellent mechanical properties and good buffering properties.

The polyethylene resin composition constituting the non-crosslinked extruded foam sheet made of polyethylene resin according to the present embodiment uses a linear polyethylene (A) and a branched high pressure method low density polyethylene (B) using a known method. Can be produced by polymer blending.
Examples of the polymer blending method include a melt mixing method using a single screw extruder, a twin screw extruder, a Banbury mixer, a pressure kneader, a heated roll kneader, and the like.
As a method of adding the various additives and the foaming agent to the polyethylene resin composition, when the linear polyethylene (A) and the branched high pressure method low density polyethylene (B) are mixed, various additives are added in advance. Mixing with linear polyethylene (A) or branched high-pressure low-density polyethylene (B), and once adding a foaming agent after making a molded product, linear polyethylene (A) and branched high-pressure When mixing the method low density polyethylene (B), a method of previously mixing various additives and a foaming agent together with the linear polyethylene (A) or the branched high pressure method low density polyethylene (B) is adopted. You can also

As a method for producing the non-crosslinked extruded foam sheet made of polyethylene resin according to the present embodiment, for example, linear polyethylene (A) together with various additives and a foaming agent in advance using an extruder, preferably an extruder with a vent. And a high-pressure branched low-density polyethylene (B), kneaded and foamed simultaneously with extrusion through a die such as a T-die or an annular die attached to the extruder, and a non-crosslinked extruded foam sheet made of polyethylene resin Is the way to get.
Examples of the blowing agent used here include inorganic gas blowing agents such as carbon dioxide, nitrogen, argon, and air; volatile blowing agents such as propane, butane, pentane, hexane, cyclobutane, cyclohexane, trichlorofluoromethane, and dichlorodifluoromethane. It is. The addition amount of the foaming agent is preferably 8 to 20% by mass, particularly 10 to 15% by mass, based on 100% by mass of the polyethylene resin composition constituting the non-crosslinked extruded foam sheet made of the polyethylene resin of the present invention. The range of parts is preferred.
In this method for producing a non-crosslinked extruded foam sheet made of polyethylene resin, a tandem comprising two extruders so that the resin temperature during extrusion is in the range of −6 to −2 ° C. of the melting point of the polyethylene resin composition. By controlling the temperature setting of the cylinder of the mold extruder, extrusion foaming can be performed under these conditions.
Next, the present invention will be described with reference to examples and reference examples.

Hereinafter, the present embodiment will be described in more detail with reference to examples and comparative examples, but the present embodiment is not limited to only these examples. The measurement method and the evaluation method used in this embodiment are as follows.
(1) Density The density was measured according to JIS-K-7112: 1999.
(2) Melt flow rate (MFR)
Measured according to JIS-K-7210: 1999 (temperature = 190 ° C., load = 2.16 kg).
(3) Molecular weight distribution Using 150-C ALC / GPC manufactured by Waters, Shodex AT-807S and Tosoh TSK-gelGMH-H6 were used in series as a column, and measurement by gel permeation chromatography was performed. Using trichlorobenzene containing 10 ppm of Irganox 1010 as a solvent, the molecular weight distribution (Mw / Mn) was determined with a molecular weight distribution measuring apparatus measuring at 140 ° C.

(4) Melt tension Melt tension was measured using a Capillograph 1D type apparatus manufactured by Toyo Seiki Seisakusho, nozzle diameter 0.770 mm, nozzle length 50.8 mm, temperature of 190 ° C, extrusion rate 6 mm / min, 23 ° C. Was carried out under the condition of a take-up speed of 2 m / min at room temperature.
(5) Charpy impact strength It measured according to JIS-K-7111-1: 2006 (temperature = -25 degreeC).
(6) Flexural modulus Measured according to JIS-K-7171: 2008.
(7) Apparent density A non-crosslinked extruded foam sheet made of polyethylene resin was cut into a predetermined size (15 cm × 15 cm), and its thickness and weight were measured to obtain an apparent density.

(8) Closed cell ratio It measured according to ASTM D-2856, and calculated | required by the following formula.

Closed cell ratio (%) = [Vx− (Va × ρf / ρs)] × 100
[Va- (Va × ρf / ρs)]
Vx: Actual volume (cm ³ ) of a non-crosslinked extruded foam sheet made of polyethylene resin
Va: Apparent volume of non-crosslinked extruded foam sheet made of polyethylene resin (cm ³ )
ρf: Density of non-crosslinked extruded foam sheet made of polyethylene resin (g / cm ³ )
ρs: density of polyethylene-based resin composition (g / cm ³ )

(9) Heat-resistant stability Cut from a non-crosslinked extruded foam sheet made of polyethylene resin into a predetermined size (15 cm × 15 cm), and write an orthogonal marked line with a length of 10 cm each parallel to each side at the center. The sample is placed in a 100 ° C. hot air circulating oven, heated for 2 hours, taken out, and naturally cooled to room temperature. The heat shrinkage was calculated by measuring the length and thickness of each marked line of the heat-treated sample. Evaluation was made according to the following evaluation criteria.
◯: When the heat shrinkage rate of each marked line is 2% or less and the heat shrinkage rate in the thickness direction is 5% or less.
X: When the heat shrinkage rate of each marked line exceeds 2% or the heat shrinkage rate in the thickness direction exceeds 5%.

(10) Tear strength A non-crosslinked extruded foam sheet made of polyethylene resin was cut into a predetermined size (15 cm × 15 cm) and was torn by hand. Evaluation was made according to the following evaluation criteria.
○: Not easily avoided.
X: Avoid easily.
(11) Surface resistivity It measured according to JIS-K-6911-1: 1995 (applied voltage 500V).

<Resin sample preparation>
[Adjustment of linear polyethylene (A)]
(1) Preparation of solid catalyst [A-1] (1-1) Synthesis of complex soluble in inert hydrocarbon solvent 175 g of dibutyl magnesium and 30 g of triethylaluminum together with 1 liter of hexane and made of stainless steel with a capacity of 4 liters placed in a vessel, by reacting with stirring for 2 hours at 85 ° C., it was synthesized complex composition _{AlMg 5 (C 2 H 5)} 3 (C 4 H 9) 10.
(1-2) Preparation of support 2740 ml of trichlorosilane (HSiCl ₃ ) as a 2 mol / l n-heptane solution was charged into a 15 liter reactor sufficiently purged with nitrogen, and kept at 50 ° C. with stirring. in the composition formula _{AlMg 6 (C 2 H 5)} 3 (n-C 4 H 9) 10.8 (On-C 4 H 9) the organomagnesium component represented by _1.2 n-heptane solution 7 liters (magnesium terms 5 mol) was added over 1 hour, and the mixture was further reacted with stirring at 50 ° C. for 1 hour. After completion of the reaction, the supernatant was removed and washed 4 times with 7 liters of n-hexane to obtain a solid material slurry. As a result of separation and drying analysis of this solid, it contained 8.62 mmol of Mg, 17.1 mmol of Cl, and 0.84 mmol of n-butoxy group (On-C ₄ H ₉ ) per gram of the solid.

(1-3) Preparation of Solid Catalyst A slurry containing 500 g of the solid was reacted with 2160 ml of n-butyl alcohol 1 mol / liter n-hexane solution at 50 ° C. for 1 hour with stirring. After completion of the reaction, the supernatant was removed and washed once with 7 liters of n-hexane. The slurry was kept at 50 ° C., and 970 ml of n-hexane solution of 1 mol / liter of diethylaluminum chloride was added with stirring and reacted for 1 hour. After completion of the reaction, the supernatant was removed and washed twice with 7 liters of n-hexane. This slurry was kept at 50 ° C., 270 ml of n-hexane solution of 1 mol / liter of diethylaluminum chloride and 270 ml of n-hexane solution of 1 mol / liter of titanium tetrachloride were added and reacted for 2 hours. After completion of the reaction, the supernatant was removed and washed with 7 liters of n-hexane four times while maintaining the internal temperature at 50 ° C. to obtain a solid catalyst component as a hexane slurry solution. This solid catalyst was separated, dried and analyzed, and as a result, 0.52 mmol of titanium was contained per gram of the solid catalyst.

(2) Polymerization A combination of solid catalyst [A-1] and triisobutylaluminum was used as the catalyst.
A stainless steel polymerization vessel having a reaction volume of 300 liters was used for the polymerization. The sum of the volume of the solvent in the polymerization vessel and the volume of polyethylene measured by a level gauge using γ-rays is 170 L, and the rate per volume at which the solvent and polyethylene are constantly extracted from the polymerization vessel is 51 L. Liter / h. Therefore, the average residence time was 1.1 hours. The polymer was withdrawn from the polymerization vessel 1 at a rate of 10 kg / h. Under the conditions of a polymerization temperature of 86 ° C. and a polymerization pressure of 0.6 MPa, the catalyst is 0.5 g / h of the solid catalyst [A-1] and 20 mmol / h of the organoaluminum compound [B-1] in terms of Al atom. h and hexane were introduced at a rate of 40 l / h. Hydrogen is used as the molecular weight regulator, ethylene, hydrogen and propylene, so that the gas phase concentration of hydrogen is 43 mol%, the gas phase concentration of propylene is 2.4 mol%, and the supply amount of ethylene is 10 kg / h. The polymerization was carried out by feeding to a polymerization vessel. The catalytic activity in the polymerization vessel was 20000 g / g / h.
Powdered polyethylene was produced by the polymerization.

[Preparation of branched high-pressure method low-density polyethylene (B) ethylene polymer or copolymer of ethylene and α-olefin]
(B) Ethylene and α-olefin were radically polymerized in a known autoclave type reactor to obtain a branched high-pressure method low density polyethylene (B) having a density of 918 kg / m ³ and MFR of 2.0 g / 10 min. The density was 951 kg / m ³ , the MFR was 7.8 g / 10 min, and the molecular weight distribution (Mw / Mn) was 5.8.

[Example 1]
Branch of density 951 kg / m ³ , MFR 7.8 g / 10 min, molecular weight distribution (Mw / Mn) 5.8 linear polyethylene (A) 80% by mass and density 918 kg / m ³ , MFR 2.0 g / 10 min DLTP Yoshitomi (manufactured by API Corporation) 1000 ppm by weight, calcium stearate (manufactured by Nippon Oil & Fats Co., Ltd.) 2400 ppm by weight in a polyethylene resin composition mixed in a proportion of 20% by mass of a high-pressure method low density polyethylene (B) Irganox 1076 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 2000 ppm by weight was added, and a TEX-44 (screw diameter 44 mm, L / D = 35) manufactured by Nippon Steel Works was used, It was granulated by melt kneading at a temperature of 220 ° C. The density of the obtained polyethylene resin composition was 944 kg / m ³ , MFR 5.6 g / 10 min, and the melt tension was 20 mN. Moreover, Charpy impact strength was 8.7 KJ / m < ² > in -25 degreeC, and the bending elastic modulus was 640 Mpa using this polyethylene-type resin composition as a base material. 95% by mass of the polyethylene resin composition, 5% by mass of Nonion S-220R (Nippon Yushi Co., Ltd.), 0.5 part by weight of a bubble regulator masterbatch (Cermic MB1023 manufactured by Sankyo Kasei Co., Ltd.) After feeding into the first extruder of φ90 mm of the extruder and melting in the extruder, 13% by mass of butane (isobutane / normal butane = 95/5 (molar ratio)) as a foaming agent is injected from the middle of the extruder and kneaded. Then, it cooled to the temperature range (125 degreeC) suitable for foaming with the 2nd extruder of (phi) 150mm, and extrusion foamed in air | atmosphere from the cyclic | annular die | dye whose exit diameter is 145mm.

The extruded and foamed cylindrical foam was cooled along a cooling mandrel having a diameter of 520 mm and cut at one point to obtain a sheet-like non-crosslinked extruded foam sheet made of polyethylene resin. The apparent density was 63.9 kg / m ³ , the closed cell ratio was 93%, the heat stability was good (◯), the tear resistance was good (◯), and the surface resistivity was 3.8 × 10 ¹² Ω. .

[Comparative Example 1]
It is only a linear polyethylene (A) having a density of 951 kg / m ³ , MFR of 7.8 g / 10 min, a molecular weight distribution (Mw / Mn) of 5.8 melt tension of 15 mN, and a branched high-pressure method low density polyethylene ( The same procedure as in Example 1 was carried out except that B) was not blended, but a non-crosslinked extruded foam sheet made of polyethylene resin was not obtained.

[Comparative Example 2]
<Resin sample preparation>
[Preparation of linear polyethylene (A); production method of ethylene homopolymer]
(1) Preparation of solid catalyst component [A] Hexane of organic magnesium compound represented by composition formula AlMg ₆ (C ₄ H ₉ ) ₁₂ (OC ₃ H ₇ ) ₃ in a 200 ml stainless steel autoclave sufficiently nitrogen-substituted 40 ml of a solution (corresponding to 37.8 mmol as the total amount of aluminum and magnesium) was charged, and 40 ml of hexane containing 2.27 g (37.8 mmol) of methylhydropolysiloxane was added dropwise over 30 minutes while stirring at 25 ° C. After dropping, the mixture was heated to 80 ° C. and reacted with stirring for 3 hours to obtain an organomagnesium compound to be brought into contact with the titanium compound.
An organomagnesium compound represented by the composition formula AlMg ₆ (C ₄ H ₉ ) ₁₂ (OC ₃ H ₇ ) ₃ is charged with 2400 ml of hexane in an 8 L stainless steel autoclave sufficiently purged with nitrogen and stirred at −5 ° C. 1300 ml of hexane solution (corresponding to 521 mmol of magnesium) and 1300 ml of 0.5 mol / L titanium tetrachloride in hexane were simultaneously added dropwise over 2 hours. After dropping, the mixture was further aged with stirring at 10 ° C. for 1 hour, and then the supernatant was removed and washed with 3000 ml of hexane four times to prepare a solid catalyst component [A].

(2) Polymerization was conducted in a polymerization reactor having a polymerization reaction volume of 230 L. The polymerization temperature is 86 ° C. and the polymerization pressure is 0.97 MPa. The Ziegler-Natta catalyst synthesized in this polymerization vessel was introduced at a rate of 0.3 g / hr, triisobutylaluminum was introduced at a rate of 24 mmol / hr, and normal hexane was introduced at a rate of 52 L / hr. The mixture was polymerized by introducing a mixed gas of ethylene and hydrogen (the gas composition was adjusted so that the molar ratio of hydrogen and ethylene + hydrogen could be maintained at 46%). The obtained ethylene homopolymer powder had a density of 966 kg / m ³ , an MFR of 6.9 g / 10 min, and a molecular weight distribution (Mw / Mn) of 8.4 as measured by gel permeation chromatography.
A polyethylene resin composition was prepared in the same manner as in Example 1 except that the above linear polyethylene was used. However, a non-crosslinked extruded foam sheet made of polyethylene resin was not obtained.

  The present invention has good processability, a good foamed state, excellent mechanical properties, and is suitable as a non-crosslinked extruded foam sheet made of polyethylene resin.

Claims (6)

Non-crosslinked extruded foam sheet made of polyethylene resin having an apparent density of 30 g / L to 200 g / L and a closed cell ratio of 70% or more, and the density of the polyethylene resin composition constituting the extruded foam sheet is 935 to 970 kg / m ^{3. A} non-crosslinked extruded foam sheet made of polyethylene resin, having a Charpy impact strength at −25 ° C. of 3.0 KJ / m ² or more and a flexural modulus of 400 MPa or more.   In the polyethylene resin composition constituting the non-crosslinked extruded foam sheet made of polyethylene resin, the melt flow rate at 190 ° C. and a load of 2.16 kg is 0.1 to 20 g / 10 minutes, and the melt tension at 190 ° C. is 15 mN or more. The non-crosslinked extruded foam sheet made of polyethylene resin according to claim 1. In the polyethylene resin composition constituting the non-crosslinked extruded foam sheet made of polyethylene resin, 90-40% by mass of linear polyethylene (A) satisfying the following requirements (a-1) to (a-4): The branched high-pressure method low-density polyethylene (B) satisfying the requirements of (b-1) to (b-3) is contained in an amount of 10 to 60% by mass. A polyethylene resin non-crosslinked extruded foam sheet as described.
(A-1) An ethylene homopolymer or a copolymer comprising an ethylene unit and one or more α-olefin units having 3 to 20 carbon atoms.
(A-2) The density is 935 to 975 kg / m ³ .
(A-3) The melt flow rate at 190 ° C. and a load of 2.16 kg is 0.1 to 20 g / 10 min.
(A-4) Mw / Mn calculated | required by the gel permeation chromatography method is 3-7.
(Mn is the number average molecular weight, Mw is the weight average molecular weight, and Mw / Mn is the molecular weight distribution.)
(B-1) The density is 910 to 930 kg / m ³ .
(B-2) The melt flow rate at 190 ° C. and a load of 2.16 kg is 0.1 to 10 g / 10 min.
(B-3) The melt tension at 190 ° C. is 20 mN or more. The polyethylene-based resin according to any one of claims 1 to 3, wherein the surface resistivity of the non-crosslinked extruded foam sheet made of polyethylene resin is 1.0 x 10 ^{8 to} 1.0 x 10 ¹⁴ Ω. Non-crosslinked extruded foam sheet made of resin.   The polyethylene resin composition constituting the non-crosslinked extruded foam sheet made of polyethylene resin, wherein the polyethylene resin composition contains 5 to 30% by mass of an antistatic agent. A non-crosslinked extruded foam sheet made of polyethylene resin according to claim 1.   A condition in which a polyethylene-based resin composition is impregnated with a gas-based foaming agent in the range of 8 to 20% by mass and the resin temperature at the time of extrusion is in the range of −6 to −2 ° C. of the melting point of the polyethylene-based resin composition. The method for producing a non-crosslinked extruded foam sheet made of polyethylene resin according to any one of claims 1 to 5, wherein the foamed product is extruded and foamed.