JP2001226496A - Polyethylene resin sheet and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyethylene resin sheet excellent in tensile modulus, tensile strength, impact resistance, heat resistance, moldability and processability and transparency and capable of obtaining by low-temperature molding and a method for producing the above sheet. SOLUTION: This polyethylene sheet is obtained from a resin composition comprising (A) 98-55 wt.% ethylene homopolymer or ethylene-α-olefin copolymer having 0.93-0.97 g/cm3 density and (B) 2-45 wt.% ethylene copolymer satisfying requirements of (a) 0.86-0.94 g/cm3 density, (b) 0.01-50 g/10 min melt flow rate and (c) 1.5-4.5 molecular weight distribution (Mw/Mn), etc., and has 100 μm-5 mm thickness and 4,500-12,000 kgf/cm2 modulus. This method for producing the polyethylene resin sheet is characterized by being obtained by air-cooling blow film extrusion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene resin sheet which is used for packaging materials, containers and the like and has excellent tensile modulus, tensile strength, impact resistance, moldability and transparency, and a method for producing the same. The present invention also relates to a polyethylene resin sheet suitably used for clean sheets and containers used in the fields of foods, medical care, electronic materials and the like, particularly food containers conforming to ministerial ordinances such as milk, and a method for producing the same.

[0002]

2. Description of the Related Art In the field of sheets for providing cups, bottles and the like, heat resistance, rigidity, impact resistance, transparency and the like have been required. A resin composition containing a series of resins is used. In addition, as containers for foods such as milk and dairy products, medical care, and electronic materials, clean containers that do not transfer additives, low molecular weight substances, etc. in the resin component to the contents or packaged items, and do not have the effect of deodorization, etc. Is required. As such a clean container, a resin made of a high-pressure radical method ethylene polymer or the like that meets the ministerial ordinance of milk or the like is used for packaging materials, bags, and the like.

[0003]

However, although high-density polyethylene is excellent in heat resistance, rigidity, etc., it has problems in transparency, flexibility, etc., so it is necessary to check the contents and foreign substances therein. In certain applications, such as cups, bags, etc., where transparency and flexibility are required, such as those formed from sheets, the advance has been delayed. In addition, since high-density polyethylene has a high molding temperature, it is generally necessary to add an antioxidant for preventing resin deterioration. In addition, since high-density polyethylene contains halogen such as chlorine as a catalyst residue,
It was necessary to add a halogen neutralizer (acid absorber) such as calcium stearate and hydrotalcite. In addition, additives such as lubricants are also used. Therefore, in the fields of food, medicine, electronic materials, etc., where packaging materials and containers are required so that the additive does not migrate to the contacted objects such as contents and products, the use of polyethylene resin sheets made of high-density polyethylene is not was difficult. Further, even if a halogen neutralizer is used, it is difficult to completely remove the halogen in the polyethylene resin sheet, and there is a problem in cleanliness.

On the other hand, the high pressure radical process ethylene polymer is
Although excellent in moldability, transparency, etc., tensile strength,
Poor mechanical strength such as impact resistance, heat resistance, rigidity (lumbar strength), etc. As a material having excellent mechanical strength such as transparency, tensile strength and impact resistance, a linear low-density polyethylene can be cited, but there is a problem that the rigidity and the like as a sheet are inferior.

In general, a polyethylene resin sheet made of a high-density polyethylene resin is obtained by forming a sheet of a polyolefin resin by a T-die method and cooling the sheet with a chill roll for cooling. This is because the extruded resin cannot be pulled up by the air-cooled inflation method due to insufficient cooling of the sheet.

However, high-density polyethylene has a molding temperature of 200 ° C.
Unless the above high temperature is set, molding is difficult, and additives such as an antioxidant and a halogen neutralizer excluding halogen caused by the catalyst have to be blended. For this reason, use in food, medical and other fields is currently restricted. In particular, since high-density polyethylene has a high crystallization rate, it is difficult to form a uniform and strong polyethylene resin sheet unless the chill roll for cooling is molded while heating it, so accurate temperature control is required. Problem. In addition, when the polyethylene resin sheet does not uniformly hit the chill roll, the polyethylene resin sheet has irregularities and has a defect of being oriented in one direction (longitudinal direction: MD direction). Further, there is a problem that the molding speed is slower than the inflation molding.

Accordingly, an object of the present invention is to provide a polyethylene resin sheet which is excellent in tensile modulus, tensile strength, impact resistance, heat resistance, moldability and transparency, and particularly excellent in thermoformability, and a method for producing the same. Another object of the present invention is to provide a thick polyethylene resin sheet having no unevenness, uniform crystallization, high strength and high productivity, and a method for producing the same. Further, the object of the present invention is used in the fields of food, medicine, electronic materials, etc. where clean packaging materials, containers, etc. are required, tensile modulus, tensile strength, impact resistance, heat resistance, moldability, An object of the present invention is to provide a polyethylene resin sheet having excellent transparency and a method for producing the same.

[0008]

The polyethylene tree of the present invention
The fat sheet has (A) a density of 0.93 to 0.97 g / cm. ^Three 
Ethylene homopolymer or ethylene-α-olefin
98 to 55% by weight of the copolymer and (B)
2 to 45% by weight of an ethylene copolymer satisfying the requirement of (d)
% And a thickness of 100 μm to
5 mm, measured according to ASTM D882
The elastic modulus is 4500-12000kgf / cm ^Two In the range
There is a feature. (A) The density is 0.86 to 0.94 g / cm^Three (B) a melt flow rate of 0.01 to 50 g / 10;
(C) Molecular weight distribution (Mw / Mn) is 1.5 to 4.5, (d) Elution temperature by continuous heating elution fractionation method (TREF)
25% of the total obtained from the integrated elution curve of the elution amount curve
Elution temperature T_{twenty five}And the temperature T at which 75% of the whole elutes₇₅When
Difference T₇₅-T_{twenty five}And the density d, the relationship of the following (Equation 1)
Satisfaction (Equation 1) T₇₅-T_{twenty five}≦ −670 × d + 644

[0009] The polyethylene resin sheet of the present invention is desirably obtained by air-cooled inflation molding. Further, the polyethylene resin sheet of the present invention,
It may be used as a polyethylene resin sheet for thermoforming. Further, the resin composition may have (C) a high-pressure radical weight of 30% by weight or less based on the total amount of (A) an ethylene homopolymer or an ethylene / α-olefin copolymer and (B) an ethylene copolymer. It is desirable to further contain an ethylene polymer obtained by a legal method. Further, it is desirable that the additive compounded in the resin composition is an additive that does not substantially migrate to the contacted object, or that no additive is compounded in the resin composition.

Further, the ethylene copolymer (B) further satisfies the following requirements (e) and (f) (B1)
Desirably, it is an ethylene copolymer. (E) orthodichlorobenzene (ODC) at 25 ° C.
B) The soluble content X (% by weight), the density d and the melt flow rate (MFR) satisfy the relationship of the following (Formula 2) and (Formula 3) (Formula 2) d−0.008 log MFR ≧ 0.93 X <2.0 (Equation 3) d−0.008 log MFR <0.93 X <9.8 × 10 ³ × (0.9300−d + 0.008)
(logMFR) ² +2.0 (f) Presence of multiple peaks in elution temperature-elution amount curve by continuous heating elution fractionation method (TREF)

Further, the ethylene copolymer (B) further satisfies the following requirements (g) and (h) (B2)
Desirably, it is an ethylene copolymer. (G) elution temperature by continuous Atsushi Nobori elution fractionation (TREF) - it is one peak of elution curve and the T ₇₅ -T ₂₅ and density d is, satisfy the relation of the following (Equation 4) ( (H) T ₇₅ −T ₂₅ ≧ −300 × d + 285 (h) One or two melting point peaks, and the highest melting point T _ml and density d satisfy the relationship of the following (Formula 5) ( Formula 5) T _ml ≧ 150 × d−17

Further, the (B2) ethylene copolymer includes:
Further, it is desirable to satisfy the following requirement (i). (I) Melt tension (MT) and melt flow rate (MFR) satisfy the following (Equation 6) (Equation 6) logMT ≦ −0.572 × logMFR + 0.3 Further, the ethylene copolymer (B) Is a linear ethylene copolymer obtained by copolymerizing ethylene and α-olefin in the presence of a catalyst containing at least an organic cyclic compound having a conjugated double bond and a transition metal compound of Group IV of the periodic table It is desirable that Further, the halogen concentration in the polyethylene resin sheet is desirably 10 ppm or less. The molded article of the present invention is obtained by subjecting the polyethylene resin sheet according to any one of claims 1 to 10 to an extrusion molding method, an injection molding method, a hollow molding method, a compression molding method, or a thermoforming method. It is characterized by being formed.

Further, the method for producing a polyethylene resin sheet of the present invention is characterized in that (A) a density of 0.93 to 0.97 g / cm ³
98 to 55% by weight of the ethylene homopolymer or ethylene / α-olefin copolymer of (B)
A resin composition containing 2 to 45% by weight of an ethylene copolymer satisfying the requirement (d);
Under the conditions of a molding temperature of 0 ° C. or less and a blow-up ratio of 1.2 to 3.0, a thickness of 100 μm to 5 mm, ASTM D8
The elastic modulus measured according to No. 82 is 4500 to 12000
It is characterized by being formed on a polyethylene resin sheet having a range of kgf / cm ² by an air-cooled inflation molding method.

Further, in the method for producing a polyethylene resin sheet of the present invention, the additive compounded in the resin composition is an additive which does not substantially migrate to the contacted object, or the additive is added to the resin composition. Is desirably not blended. In the method for producing a polyethylene resin sheet of the present invention, it is preferable that a hollow tube obtained by air-cooling inflation molding of the resin composition be sandwiched and crushed to form a sheet.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The (A) ethylene homopolymer or ethylene / α-olefin copolymer in the present invention has a density of 0.93 to 0.93.
0.97 g / cm ³ , preferably 0.94 to 0.96 g / cm ³
cm ³ high density polyethylene. (A) The density of the ethylene homopolymer or ethylene / α-olefin copolymer (hereinafter referred to as (A) high-density polyethylene) is 0.9.
When the density is less than 3 g / cm ³ , heat resistance and mechanical strength may not be satisfied, and when the density exceeds 0.97 g / cm ³ , there is a problem in molding processability and it is difficult to industrially produce. It has a problem (however, the density is 0.94 g / cm ³⁾
Is less than the (B) component).

(A) The high-density polyethylene preferably has a melt flow rate (MFR) of 0.01 to 50 g / 1.
The range is 0 minute, more preferably 0.05 to 30 g / 10 minutes, and still more preferably 0.1 to 10 g / 10 minutes.
(A) MFR of high-density polyethylene is 0.01 g / 10
If the amount is less than 10 minutes, the extrudability deteriorates and the MFR is 50 g / 1.
If the time exceeds 0 minutes, there is a possibility that a problem may occur in pulling up the resin during inflation molding.

(A) The high-density polyethylene is a high-density polyethylene obtained at low, medium and high temperatures using a Ziegler catalyst, a Phillips catalyst, a metallocene catalyst or the like. The α-olefin has 3 to 20, preferably 3 to 12 carbon atoms, and specifically includes propylene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene. , 1-decene, 1-dodecene and the like.

The method for producing (A) the high-density polyethylene according to the present invention is carried out by a gas phase polymerization method, a slurry polymerization method, a solution polymerization method or the like substantially in the absence of a solvent in the presence of the catalyst. With oxygen and water turned off, butane,
In the presence or in the presence of an inert hydrocarbon solvent exemplified by aliphatic hydrocarbons such as pentane, hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. Manufactured in the presence. The polymerization conditions are not particularly limited, but the polymerization temperature is usually 15 to 350 ° C, preferably 20 to 200 ° C.
C., more preferably 50 to 110 ° C., and the polymerization pressure is usually normal pressure to 70 kg / cm ² G, preferably normal pressure to 20 kg / cm ² G in the case of the low / medium pressure method, and is usually in the case of the high pressure method. 1500 kg / cm ² G or less is desirable. The polymerization time is usually from 3 minutes to 10 hours, preferably from 5 minutes to 5 hours in the case of the low and medium pressure method. In the case of the high-pressure method, it is usually 1 minute to 30 minutes, preferably about 2 minutes to 20 minutes. In addition, the polymerization is not particularly limited to a single-stage polymerization method, as well as a multi-stage polymerization method of two or more stages in which polymerization conditions such as hydrogen concentration, monomer concentration, polymerization pressure, polymerization temperature, and catalyst are different from each other.

The ethylene copolymer (B) in the present invention is a copolymer of ethylene and an α-olefin satisfying the requirements (a) to (d) described below.

The α-olefin of the ethylene copolymer (B) in the present invention has 3 to 20 carbon atoms, preferably 3 to 20 carbon atoms.
To 12; specifically, propylene, 1-pentene, 4-methyl-1-pentene, 1-hexene,
-Octene, 1-decene, 1-dodecene and the like. Further, the content of these α-olefins is desirably selected in a range of usually 30 mol% or less, preferably 3 to 20 mol% or less.

In the present invention, the (B) ethylene copolymer
(A) The density is 0.86 to 0.94 g / cm^Three , Preferred
Ha, 0.89 ~ 0.94g / cm^Three , More preferably
Is 0.90 to 0.93 g / cm^Three Range. Density
0.86 g / cm^Three Less than, rigidity (lumbar strength), heat resistance
The properties are inferior. In addition, the density is 0.94 g / cm ^Three 
Above, the transparency, tear strength, impact resistance, etc. of the sheet
Will be insufficient.

Further, (B) M of the ethylene copolymer (B)
FR is 0.01 to 50 g / 10 min, preferably 0.0 to 50 g / 10 min.
3 to 30 g / 10 min, more preferably 0.1 to 10 g /
The range is 10 minutes. When the MFR is less than 0.01 g / 10 minutes, the moldability is poor, and when the MFR exceeds 50 g / 10 minutes, the tear strength, impact resistance, and the like are poor.

In the present invention, the (B) ethylene copolymer (c) has a molecular weight distribution (Mw / Mn) of 1.5 to 4.5;
Preferably 2.0 to 4.0, more preferably 2.5 to
It is in the range of 3.0. If Mw / Mn is less than 1.5, the moldability is poor, and if Mw / Mn exceeds 4.5, the tear strength, impact resistance and the like are poor. Here, the molecular weight distribution (Mw / Mn) of the ethylene copolymer is determined by gel permeation chromatography (GPC).
w) and the number average molecular weight (Mn) are determined, and their ratio (Mw)
/ Mn).

The ethylene copolymer (B) in the present invention was determined from, for example, an integrated elution curve of an elution temperature-elution amount curve (TREF) as shown in FIG. the difference T ₇₅ -T ₂₅ and the density d of the temperature T ₇₅ to 75% of the total temperature T ₂₅ is eluted 25% of the total is eluted, and satisfies the following relationship (equation 1). When the equation _{(1) T 75 -T 25 ≦ -670} × d + 644 T 75 -T 25 and density d do not satisfy the relation of the equation (1) becomes as low-temperature heat-sealing property is inferior.

The method of measuring TREF is as follows. First, a sample is added to ODCB to which an antioxidant (for example, butylhydroxytoluene) has been added so that the sample concentration becomes 0.05% by weight, and heated and dissolved at 135 ° C. 5 ml of this sample solution is injected into a column filled with glass beads, cooled to 25 ° C. at a cooling rate of 0.1 ° C./min, and the sample is deposited on the surface of the glass beads. Next, while flowing ODCB through this column at a constant flow rate, the column temperature was raised to 50 ° C.
The sample is sequentially eluted while heating at a constant rate of / hr. At this time, the concentration of the sample eluted in the solvent is continuously detected by measuring the absorption of the asymmetric stretching vibration of methylene at a wave number of 2925 cm ^-1 with an infrared detector.
From this value, the concentration of the ethylene copolymer in the solution is quantitatively analyzed to determine the relationship between the elution temperature and the elution rate. According to the TREF analysis, a change in the elution rate with respect to a temperature change can be continuously analyzed with a very small amount of sample, so that a relatively fine peak which cannot be detected by the fractionation method can be detected.

The (B) ethylene copolymer in the present invention further satisfies the requirements of (e) and (f) described below, or (B1) an ethylene copolymer, or (g) and (h) described below. (B2) is preferably any one of the ethylene copolymers satisfying the requirement of (B2).

In the present invention, (e) the amount X (wt%) of the ODCB-soluble component at 25 ° C., the density d and the MFR of the ethylene copolymer (B1) are expressed by the following formulas (2) and (3). (Equation 2) When d−0.008 log MFR ≧ 0.93, X <2.0 (Equation 3) When d−0.008 log MFR <0.93, X <9.8 × 10 ³ x (0.9300-d + 0.008
log MFR) ² +2.0, preferably X <1.0 d−0.008 log MFR <0.93, d <0.008 log MFR <0.93, X <7. 4 × 10 ³ × (0.9300−d + 0.008
log MFR) ² +2.0, more preferably X <0.5 d-0.008 log MFR ≧ 0.93, X <0.5 d−0.008 log MFR <0.93, X <5 0.6 × 10 ³ × (0.9300−d + 0.008
log MFR) ² +2.0.

Here, the amount X of the ODCB-soluble component at 25 ° C. is measured by the following method. Sample 0.5
g in 20 ml ODCB at 135 ° C. for 2 hours,
After completely dissolving the sample, cool it to 25 ° C. After leaving this solution at 25 ° C. overnight, the filtrate is collected by filtering through a Teflon filter. This filtrate, which is a sample solution, was subjected to infrared spectroscopy to measure the asymmetric stretching vibration wave number of methylene 2925c.
The absorption peak intensity around m ^-1 is measured, and the sample concentration is calculated from a calibration curve created in advance. From this value, the ODCB-soluble content at 25 ° C. is determined.

The ODCB-soluble component at 25 ° C. is a component having a high degree of branching and a low molecular weight component contained in the ethylene copolymer, which causes a reduction in heat resistance and stickiness of the surface of the molded product, and causes problems of hygiene and molding. It is desirable that this content be low because it causes blocking of the body surface. ODC
The amount of the B-soluble component is affected by the α-olefin content and the molecular weight of the whole copolymer, that is, the density and the MFR. Therefore, the fact that the density and the amounts of MFR and ODCB-soluble component, which are indicators, satisfy the above relationship indicates that the uneven distribution of α-olefin contained in the whole copolymer is small.

Further, the ethylene copolymer (B1) in the present invention has a plurality of peaks in the elution temperature-elution amount curve obtained by (f) continuous temperature elution fractionation (TREF). This multiple peak temperature is 85 ° C
It is particularly preferred that it is present between 1 and 100 ° C. The presence of this peak increases the melting point, increases the crystallinity, and improves the heat resistance and rigidity of the molded body.

Here, as shown in FIG. 1, the ethylene copolymer (B1) was subjected to continuous heating elution fractionation (TREF).
The peak is substantially a plurality of special ethylene / α-olefin copolymers in the elution temperature-elution amount curve obtained by the above. On the other hand, the ethylene copolymer of FIG. 2 has substantially one peak in the elution temperature-elution amount curve obtained by the continuous temperature elution fractionation method (TREF).
An olefin copolymer, which corresponds to a conventional typical metallocene-based ethylene copolymer.

As shown in FIG. 3, the ethylene copolymer (B2) in the present invention is prepared by the method of (g) continuous heating elution fractionation method (T
REF) by elution temperature - is one peak of elution volume curve, and T ₇₅ -T ₂₅ and density d is one which satisfies the following relationship (Equation 4). When the equation _{(4) T 75 -T 25 ≧ -300} × d + 285 T 75 -T 25 and density d do not satisfy the relation of the equation (4) would heat resistance is inferior.

Further, the ethylene copolymer (B2) in the present invention has (h) one or two melting point peaks, and the highest melting point T _ml and the density d among them have a relationship represented by the following formula (5). I am satisfied. (Formula 5) _Tml ≧ 150 × d−17 If the melting point Tm1 and the density d do not satisfy the relationship of the above (Formula 5), the heat resistance will be poor.

Further, among the ethylene copolymers (B2), ethylene copolymers that further satisfy the following requirement (i) are preferable. (I) The melt tension (MT) and the melt flow rate (MFR) satisfy the relationship of the following (Equation 6) (Equation 6) logMT ≦ −0.572 × logMFR + 0.3 By satisfying the relationship of (1), the moldability becomes good.

As shown in FIG. 3, the ethylene copolymer (B2) has a single TREF peak as shown in FIG. ) Is not satisfied, and is distinguished from a conventional typical metallocene-based catalyst-based ethylene copolymer.

The ethylene copolymer (B) in the present invention is not particularly limited to a catalyst, a production method and the like as long as the above parameters are satisfied, but it is preferable to use an organic cyclic compound having at least a conjugated double bond. In the presence of a catalyst containing a transition metal compound of Group IV of the periodic table, ethylene and α-
Desirably, it is a linear ethylene copolymer obtained by copolymerizing an olefin. Since such a linear ethylene copolymer has a narrow molecular weight distribution and composition distribution, it is excellent in mechanical properties, heat sealing properties, heat blocking properties, and the like, and also has good heat resistance.

In the production of the ethylene copolymer (B) in the present invention, it is particularly desirable to polymerize with a catalyst obtained by mixing the following compounds a1 to a4. a1: Compound represented by the general formula Me ¹ R ¹ _p R ² _q (OR ³ ) _r X ¹⁴ _-pqr (where Me ¹ represents zirconium, titanium, or hafnium, and R ¹ and R ³ each represent a carbon number) 1 to
24 hydrocarbon groups, R ² is a 2,4-pentanedionato ligand or a derivative thereof, a benzoylmethanato ligand,
A benzoylacetonate ligand or a derivative thereof, X ¹ represents a halogen atom, p, q and r each represent 0 ≦ p
≦ 4, 0 ≦ q ≦ 4, 0 ≦ r ≦ 4, 0 ≦ p + q + r ≦ 4) a2: a compound represented by the general formula Me ² R ⁴ _m (OR ⁵ ) _n X ² _zmn (In the formula, Me ² is an element in Groups I to III of the periodic table, R ⁴
And R ⁵ are each a hydrocarbon group having 1 to 24 carbon atoms, X
² represents a halogen atom or a hydrogen atom (however, when X ² is a hydrogen atom, Me ² is limited to a Group III element of the periodic table), z represents a valence of Me ² , and m and n represent A is an integer satisfying the ranges of 0 ≦ m ≦ z and 0 ≦ n ≦ z, and 0 ≦ m + n ≦ z. A3: Organic cyclic compound having a conjugated double bond a4: Al—O—Al bond Containing modified organoaluminum oxy compound and / or boron compound

The details will be described below. The above-mentioned catalyst component a1
In the formula of the compound represented by the general formula Me ¹ R ¹ _p R ² _q (OR ³ ) _r X ¹⁴ _-pqr , Me ¹ represents zirconium, titanium or hafnium, and the types of these transition metals are limited. It is not limited to this, and a plurality of them can be used, but it is particularly preferable that the copolymer contains zirconium having excellent weather resistance. R ¹ and R ³ are each a hydrocarbon group having 1 to 24 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 8 carbon atoms. Specifically, an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group;
Alkenyl groups such as vinyl group and allyl group; phenyl group,
Aryl groups such as tolyl, xylyl, mesityl, indenyl and naphthyl; benzyl, trityl,
And aralkyl groups such as phenethyl group, styryl group, benzhydryl group, phenylbutyl group, and neofuyl group. These may have branches. R ² is 2,
It shows a 4-pentanedionato ligand or a derivative thereof, a benzoylmethanato ligand, a benzoylacetonato ligand or a derivative thereof. X ¹ represents a halogen atom such as fluorine, iodine, chlorine and bromine. p and q are respectively 0 ≦ p ≦ 4, 0 ≦ q ≦ 4, 0 ≦ r ≦ 4, 0 ≦ p + q
An integer satisfying the range of + r ≦ 4 is an integer.

Examples of the compounds represented by the general formula of the above-mentioned catalyst component a1 include tetramethyl zirconium, tetraethyl zirconium, tetrabenzyl zirconium, tetrapropoxy zirconium, tripropoxy monochlorodiconium, tetraethoxy zirconium, tetrabutoxy zirconium, tetrabutoxy titanium , Tetrabutoxy hafnium and the like, and especially Z such as tetrapropoxy zirconium and tetrabutoxy zirconium.
r (OR) ₄ compounds are preferred, and two or more of these may be used in combination. Specific examples of the 2,4-pentanedionato ligand or derivative thereof, benzoylmethanato ligand, benzoylacetonato ligand or derivative thereof include tetra (2,4-pentanedionato) zirconium. , Tri (2,4-pentanedionato)
Zirconium chloride, di (2,4-pentanedionato) dichloride zirconium, (2,4-pentanedionato) trichloride zirconium, di (2,4-pentanedionato) diethoxide zirconium, di (2,4- Pentanedionato) di-n-propoxide zirconium, di (2,4-pentanedionato) di-n
-Butoxide zirconium, di (2,4-pentanedionato) dibenzyl zirconium, di (2,4-pentanedionato) dineofylzirconium, tetra (dibenzoylmethanato) zirconium, di (dibenzoylmethanato) die Zirconium toxide, zirconium di (dibenzoylmethanato) di-n-propoxide, zirconium di (dibenzoylmethanato), zirconium di (n-butoxide), zirconium diethoxide zirconium, di (benzoylacetonate) ) Di-n-propoxide zirconium, di (benzoylacetonate)
And di-n-butoxide zirconium.

The general formula Me of the catalyst component a2^TwoR^Four _m(O
R^Five)_nX^Two _zmn In the formula of the compound represented by^Two Is the period
Represents a group I-III element of the table, lithium, sodium,
Potassium, magnesium, calcium, zinc, boron,
Aluminum and the like. R^FourAnd R^Five Is charcoal
A hydrocarbon group having a prime number of 1 to 24, preferably a carbon number of 1 to 1
2, more preferably 1 to 8, specifically
Group, ethyl group, propyl group, isopropyl group, butyl
Alkyl groups such as vinyl groups; alkene groups such as vinyl groups and allyl groups
Nyl group: phenyl group, tolyl group, xylyl group, mesityl
An aryl group such as a group, an indenyl group or a naphthyl group;
Jyl, trityl, phenethyl, styryl, ben
Such as a duhydryl group, a phenylbutyl group and a neofuyl group
Aralkyl groups and the like. These have branches
Is also good. X^Two Is fluorine, iodine, chlorine and bromine, etc.
Represents a halogen atom or a hydrogen atom. However
Then X ^Two Is Me when hydrogen is a hydrogen atom^Two Is boron, aluminum
Only in the case of Group III elements in the periodic table
Things. Z is Me^Two And m and m
And n satisfy the ranges of 0 ≦ m ≦ z and 0 ≦ n ≦ z, respectively.
Is an integer, and 0 ≦ m + n ≦ z.

Examples of the compound represented by the general formula of the catalyst component a2 include organolithium compounds such as methyllithium and ethyllithium; organomagnesium compounds such as dimethylmagnesium, diethylmagnesium, methylmagnesium chloride and ethylmagnesium chloride; Organic zinc compounds such as zinc and diethyl zinc; organic boron compounds such as trimethyl boron and triethyl boron; trimethyl aluminum, triethyl aluminum, tripropyl aluminum, triisobutyl aluminum, trihexyl aluminum, tridecyl aluminum, diethyl aluminum chloride, ethyl aluminum dichloride , Ethyl aluminum sesquichloride, diethyl aluminum ethoxide, diethyl aluminum Derivatives of organoaluminum compounds such as Idoraido the like.

The organic cyclic compound having a conjugated double bond of the catalyst component a3 has one or more rings having two or more, preferably 2 to 4, more preferably 2 to 3, conjugated double bonds. A cyclic hydrocarbon compound having 2 or more and having a total carbon number of 4 to 24, preferably 4 to 12; wherein the cyclic hydrocarbon compound partially has 1 to 6 hydrocarbon residues (typically, carbon A cyclic hydrocarbon compound substituted with an alkyl group or an aralkyl group of the formulas 1 to 12; two or more, preferably 2 to 4, more preferably 2 to 2, conjugated double bonds.
One or more rings having three rings and a total carbon number of 4
An organosilicon compound having a cyclic hydrocarbon group of from 24 to 24, preferably 4 to 12; said cyclic hydrocarbon group being partially substituted by 1 to 6 hydrocarbon residues or an alkali metal salt (sodium or lithium salt) Organosilicon compounds. Particularly preferably, those having a cyclopentadiene structure in any of the molecules are desirable.

The preferred compounds include cyclopentadiene, indene, azulene and their alkyl, aryl, aralkyl, alkoxy or aryloxy derivatives. Further, a compound obtained by bonding (crosslinking) these compounds via an alkylene group (the number of carbon atoms of which is usually 2 to 8, preferably 2 to 3) is also preferably used.

The organosilicon compound having a cyclic hydrocarbon group can be represented by the following general formula. A _L SiR _4-L wherein A represents the above-mentioned cyclic hydrogen group exemplified by a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, and a substituted indenyl group, and R represents a methyl group, an ethyl group, a propyl group. Alkyl groups such as methoxy, ethoxy, propoxy and butoxy groups; aryl groups such as phenyl groups; aryloxy groups such as phenoxy groups; aralkyl groups such as benzyl groups. And represents a hydrocarbon residue having 1 to 24 carbon atoms, preferably 1 to 12 carbon atoms or hydrogen, and L represents 1
≦ L ≦ 4, preferably 1 ≦ L ≦ 3.

Specific examples of the organic cyclic hydrocarbon compound of the component a3 include cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, 1,3-dimethylcyclopentadiene, indene, 4-methyl-1-indene, 4,7- C5-C24 cyclopolyene or substituted cyclopolyene such as dimethylindene, cycloheptatriene, methylcycloheptatriene, cyclooctatetraene, azulene, fluorene, methylfluorene, monocyclopentadienylsilane, biscyclopentadiene Examples include enylsilane, triscyclopentadienylsilane, monoindenylsilane, bisindenylsilane, and trisindenylsilane.

The modified organoaluminum oxy compound containing an Al—O—Al bond of the catalyst component a4 is obtained by reacting an alkylaluminum compound with water to obtain a modified organoaluminum oxy compound usually called aluminoxane. The molecule usually contains 1 to 100, preferably 1 to 50 Al-O-Al bonds. The modified organic aluminum oxy compound may be linear or cyclic.

The reaction between the organoaluminum and water is usually carried out in an inert hydrocarbon. As the inert hydrocarbon,
Aliphatic, alicyclic and aromatic hydrocarbons such as pentane, hexane, heptane, cyclohexane, benzene, toluene and xylene are preferred. The reaction ratio between water and the organoaluminum compound (water / Al molar ratio) is usually 0.25 / 1 to 1.2.
/ 1, preferably 0.5 / 1 to 1/1.

Examples of the boron compound include triethylaluminum tetra (pentafluorophenyl) borate (triethylammoniumtetra (pentafluorophenyl)
Borate, dimethylanilinium tetra (pentafluorophenyl) borate (dimethylanilinium tetra (pentafluorophenyl) borate, butylammonium tetra (pentafluorophenyl) borate, N, N-
Dimethylanilinium tetra (pentafluorophenyl) borate, N, N-dimethylaniliniumtetra (3,5 difluorophenyl) borate and the like can be mentioned.

The above catalyst may be used by mixing and contacting a1 to a4, but it is preferable to use the catalyst by supporting it on an inorganic carrier and / or a particulate polymer carrier (a5). Examples of the inorganic carrier and / or the particulate polymer carrier (a5) include a carbonaceous material, a metal, a metal oxide, a metal chloride, a metal carbonate or a mixture thereof, a thermoplastic resin, and a thermosetting resin. Suitable metals that can be used for the inorganic carrier include iron, aluminum, nickel and the like. Specifically, Si
O ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , B ₂ O ₃ ,
CaO, ZnO, BaO, ThO ₂ and the like or mixtures _{thereof, SiO 2 -Al 2 O 3,} SiO 2 -V
₂ O ₅ , SiO ₂ —TiO ₂ , SiO ₂ —V ₂ O ₅ , SiO ₂ —
MgO, SiO ₂ —Cr ₂ O _{3 and the} like. Among these, those containing at least one component selected from the group consisting of SiO ₂ and Al ₂ O ₃ as a main component are preferable. Further, as the organic compound, any of a thermoplastic resin and a thermosetting resin can be used. Specifically, particulate polyolefin, polyester, polyamide, polyvinyl chloride, polymethyl (meth) acrylate, polystyrene, poly Examples include norbornene, various natural polymers, and mixtures thereof.

The above-mentioned inorganic carrier and / or particulate polymer carrier can be used as they are. However, as a pretreatment, these carriers are preferably converted to an organic aluminum compound or a modified organic aluminum compound containing an Al—O—Al bond. After the contact treatment, it can be used as the component a5.

The process for producing the ethylene copolymer (B) in the present invention is carried out by a gas phase polymerization method, a slurry polymerization method, a solution polymerization method or the like in the presence of the above-mentioned catalyst, which substantially does not contain a solvent. In a state where oxygen, water, etc. are turned off, it is converted to aliphatic hydrocarbons such as butane, pentane, hexane and heptane, aromatic hydrocarbons such as benzene, toluene and xylene, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. It is produced in the presence or absence of the exemplified inert hydrocarbon solvents. The polymerization conditions are not particularly limited, but the polymerization temperature is usually 15 to 350 ° C, preferably 20 to 200 ° C.
C., more preferably 50 to 110 ° C., and the polymerization pressure is usually normal pressure to 70 kg / cm ² G, preferably normal pressure to 20 kg / cm ² G in the case of the low and medium pressure method, and is usually 1500 kg / cm ^{2 in} the case of the high pressure method. cm ² G or less is desirable. The polymerization time is usually from 3 minutes to 10 hours, preferably from 5 minutes to 5 hours in the case of the low and medium pressure method. In the case of the high pressure method, usually 1 minute to 3 minutes
0 minutes, preferably about 2 to 20 minutes is desirable. Also,
The polymerization is not particularly limited, such as a one-stage polymerization method, a two-stage or more multi-stage polymerization method in which polymerization conditions such as hydrogen concentration, monomer concentration, polymerization pressure, polymerization temperature, and catalyst are different from each other. A particularly preferred production method is described in JP-A-5-15-1.
No. 32518 is mentioned.

The ethylene copolymer (B) in the present invention is produced using a catalyst which does not contain halogen such as chlorine in the above-mentioned catalyst components, so that the halogen concentration is at most 10 ppm or less, preferably at most 10 ppm. 5 ppm or less, more preferably substantially free of (ND: 2 pp
m or less). By using such a halogen-free ethylene copolymer such as chlorine, there is no need to use a halogen neutralizer as in the past, and chemical stability and hygiene are excellent, especially for food packaging materials and the like. A polyethylene resin sheet suitably used in the field can be provided.

In the present invention, (C) the ethylene polymer obtained by the high-pressure radical polymerization method includes low-density polyethylene (LDPE),
Examples include vinyl ester copolymers and copolymers of ethylene with α, β-unsaturated carboxylic acids or derivatives thereof.

The low density polyethylene (LDPE) is
MFR of 0.01 to 50 g / 10 min, preferably 0.0
5 to 30 g / 10 min, more preferably 0.1 to 10 g
/ 10 minutes. Within this range, the melt tension is in an appropriate range, and the moldability is improved. If the MFR exceeds 50 g / 10 minutes, the strength of the sheet may be reduced. Further, the density is 0.91 to 0.9.
94 g / cm ³ , more preferably 0.91 to 0.935
g / cm ³ . Within this range, the melt tension is in an appropriate range, and the moldability is improved.
The melt tension is 1.5 to 25 g, preferably 3 to 25 g.
20 g, more preferably 3 to 15 g. Further, the molecular weight distribution Mw / Mn is 3.0 to 12, preferably 4.
0 to 8.0.

The above-mentioned ethylene / vinyl ester copolymers include vinyl propionate, vinyl acetate, vinyl caproate, vinyl caprylate, vinyl laurate, and vinyl stearate mainly composed of ethylene produced by a high-pressure radical polymerization method. And a copolymer with a vinyl ester monomer such as vinyl trifluoroacetate. Among them, particularly preferred is vinyl acetate. Also, 50 to 99.5% by weight of ethylene, 0.5 to 50% by weight of vinyl ester, and 0
A copolymer consisting of 49.5% by weight is preferred. In particular,
The content of vinyl ester is in the range of 3 to 30% by weight, preferably 5 to 25% by weight. The MFR of the ethylene / vinyl ester copolymer is 0.01 to 50 g / 10 min, preferably 0.05 to 30 g / min, and more preferably 0.1 to 30 g / min.
The range is 1 to 10 g / 10 minutes.

Examples of the copolymer of ethylene and an α, β-unsaturated carboxylic acid or a derivative thereof include ethylene / (meth) acrylic acid or its alkyl ester copolymer. acid,
Methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, cyclohexyl acrylate And cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, glycidyl acrylate, glycidyl methacrylate and the like. Of these, particularly preferred are alkyl esters of (meth) acrylic acid such as methyl and ethyl. In particular, the content of the (meth) acrylate is 3 to
It is in the range of 30% by weight, preferably 5 to 25% by weight.
The MFR of a copolymer of ethylene and an α, β-unsaturated carboxylic acid or a derivative thereof has a MFR of 0.01 to 50 g / 10 min, preferably 0.05 to 30 g / 10 min, and more preferably 0.1 to 10 g / min. 10 minutes.

The polyethylene resin sheet of the present invention comprises:
(A) 98 to 55% by weight of high density polyethylene;
The resin composition comprises 2 to 45% by weight of an ethylene copolymer and, if necessary, (C) an ethylene polymer (hereinafter collectively referred to as LDPE) obtained by a high-pressure radical polymerization method.

When the content of (A) the high-density polyethylene exceeds 98% by weight, the processability, transparency and flexibility of (B) the ethylene copolymer become insufficient, and the inflation molding becomes difficult. Also, low-temperature molding becomes difficult. On the other hand, when (A) the high-density polyethylene is less than 55% by weight,
Heat resistance decreases, and rigidity (lumbar strength) becomes insufficient. If the content of the (B) ethylene copolymer is less than 2% by weight, moldability, transparency, flexibility and the like are deteriorated, and inflation molding becomes difficult. Also, low-temperature molding becomes difficult. on the other hand,
(B) When the ethylene copolymer exceeds 45% by weight,
(A) Due to the shortage of high-density polyethylene, heat resistance is reduced and stiffness is insufficient.

In order to improve moldability and transparency, (C) LDPE is used to improve the total of (A) ethylene homopolymer or ethylene / α-olefin copolymer and (B) ethylene copolymer. Up to 30% by weight, preferably up to 20% by weight, can be incorporated. (C) When the high-pressure method ethylene polymer exceeds 30% by weight, the mechanical strength of the polyethylene resin sheet may be insufficient.

Although the reason for the resin composition of the present invention is not clear, low-temperature molding is possible by blending the ethylene copolymer (B). By performing the low-temperature molding, there is an advantage that deterioration of the resin due to heat hardly occurs, and it is not necessary to add an antioxidant. In addition, since molding at a low temperature reduces resin blocking, it is not necessary to add an anti-blocking agent or the like.
In addition, ethylene (co)
If the polymer (A) is produced, it is not necessary to add a halogen neutralizer (acid absorber).

In the present invention, an antioxidant, an antiblocking agent, a lubricant, an antistatic agent, an antifogging agent, an ultraviolet absorber, an organic or inorganic pigment, a nucleating agent, a crosslinking agent may be added to the resin composition. Known additives such as are not blended, or, even if additives are blended in the resin composition, the blended additives are additives that do not substantially migrate to the contacted object such as the contents. Desirably. In the present invention, an additive that elutes to the outside, for example, when the content is a liquid, an additive that is eluted in the liquid, an additive in which odor is transferred, or with time Since an additive that is unevenly distributed on the sheet surface is not included in the resin composition, a clean laminate and a container can be provided.

In the present invention, the additive which does not substantially migrate to the contacted object is a filler such as an organic or inorganic filler, which does not degrade the contacted object and which does not deteriorate the polyethylene resin sheet of the present invention. It is an additive that can be added within a range that does not essentially impair the properties. As inorganic fillers, calcium carbonate, talc, silica, clay, carion, alumina, aluminum hydroxide, magnesia, magnesium hydroxide, calcium sulfate, calcium sulfite,
Barium sulfate, aluminum silicate, calcium silicate, sodium silicate, potassium silicate, magnesium carbonate, barium carbonate, calcium oxide, titanium oxide, zinc oxide, mica, glass flake, zeolite, diatomaceous earth, perlite, permiculite, shirasu balloon, glass microsphere, Fly ash, glass beads and the like. As organic fillers, polymethyl methacrylate cross-linked products, polyethylene terephthalate cross-linked products, phenolic resin and other synthetic resin powders and fine beads,
Wood flour, pulp flour and the like can be mentioned.

The thickness of the polyethylene resin sheet of the present invention varies depending on the purpose and application, but is generally 100 μm.
To 5 mm, preferably 150 to 2 mm, more preferably 200 to 1 mm. Thickness 1
If it is less than 00 μm, there is no rigidity, and sheet molding is difficult,
If the thickness exceeds 5 mm, processing becomes difficult. Since the polyethylene resin sheet of the present invention contains the ethylene copolymer (B) in the resin composition as a raw material, the thickness can be set to 250 μm or more even by an air-cooled inflation molding method.

[0064] Polyethylene resin sheet elastic modulus of the present invention, 4500~12000kgf / cm ^2, preferably in the range of 5000~12000 kgf / cm ^2.
If the elastic modulus is less than 4500 kgf / cm ² , the rigidity of the sheet during thermoforming or as a container becomes insufficient. Elastic modulus is 1
Sheets exceeding 2000 kgf / cm ² are difficult to perform secondary forming. Here, the elastic modulus is ASTM D
It is a value measured according to 882.

The polyethylene resin sheet of the present invention can be manufactured by an air-cooled inflation method by using the above specific resin composition. That is, the production of the polyethylene resin sheet by the air-cooled inflation method can be performed by an air-cooled inflation film manufacturing apparatus.
, Preferably above the melting point to 180 ° C, blow-up ratio 1.2 to 3.0, preferably blow-up ratio 1.2 to
Extrude through a circular die from an extruder at 2.5,
This is performed by contacting with air blown from an air-cooled air ring, cooling, solidifying, taking up with a pinch roll, and winding it around a frame. With this method, it is possible to simultaneously improve the molding and the transparency of the air-cooled inflation sheet, which has been difficult to solve at the same time.

According to the method for producing a polyethylene resin sheet of the present invention, since the resin composition contains the ethylene copolymer (B), the thickness of the polyethylene resin is 250 μm or more even by the air-cooled inflation method. You can get a sheet. By manufacturing the polyethylene resin sheet by the air-cooled inflation molding method in this way, the resin is uniformly crystallized due to the slow cooling by the air-cooling without unevenness unlike the polyethylene resin sheet obtained by the T-die method. Blow-up ratio (BU) to obtain a polyethylene resin sheet that can be molded without additives from where low-temperature molding is possible and that does not adversely affect the contacted object.
R) can be adjusted and the quality can be controlled,
Compared to the T-die method, there is no ear loss, high productivity, and economical efficiency. Double-thickness sheets can be formed at once by multilayering and crushing with pinch rolls, making the thickness uniform. Is also possible.

Another advantage of the method for obtaining a multilayered polyethylene resin sheet by an air-cooled inflation molding method is that a hollow tube formed by extruding a resin composition through a circular die is heated to a temperature lower than the melting point of the resin composition. A method of sandwiching and pinching with a pinch roll at a high temperature to form a laminate, a hollow tube formed by extruding a resin composition through a circular die, and cooling by contacting air blown from an air-cooled air ring, After solidification, a method of reheating with a heated pinch roll or the like and crushing the sheet to double the sheet thickness may be used.

Examples of the molded article of the present invention include bags (bags), containers, bottles, tubes, trays, cups and the like made of the polyethylene resin sheet of the present invention. These molded articles are obtained by molding the polyethylene resin sheet of the present invention by any one of extrusion molding, injection molding, hollow molding, compression molding and thermoforming. The molding method is not particularly limited. Further, the polyethylene resin sheet may be formed into a bag shape by heat sealing and used as a pouch. In particular, the laminated form may be a laminated body of the present invention in which a laminated body is formed in advance and a laminated sheet is formed, or each layer is laminated when the molded body is molded.

[0069]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

The test method in this example is as follows. [Density] Based on JIS K6760. [MFR] Based on JIS K6760. [Mw / Mn] GPC (150C type manufactured by Waters)
And 135 ° C. ODCB was used as a solvent. The column used was GMHHR-H (S) from Tosoh. [TREF] The column was kept at 140 ° C., the sample was injected, the temperature was lowered at 0.1 ° C./min to 25 ° C., and the polymer was deposited on glass beads. The concentration of the polymer eluted at the temperature was detected by an infrared detector. (Solvent: ODCB, flow rate: 1 ml / min, heating rate: 50 ° C./hr, detector: infrared spectrometer (wavelength 2925)
cm ^-1 ), column: 0.8 cmφ × 12 cmL (filled with glass beads), sample concentration: 0.05% by weight)

[Elastic Modulus] According to ASTM D882. [Inflation moldability] The moldability during air-cooled inflation molding was evaluated according to the following criteria. ：: The resin can be stably pulled up, and molding can be performed without fluctuation of the frost. Δ: Frost fluctuates, but molding is possible. ×: The resin cannot be pulled up stably and molding cannot be performed. [Transparency (Haze)] Based on ASTM D1003.

<Evaluation of Container> [Odor and Sanitary Property]
After storage in an oven at 72 ° C. for 72 hours, the mixture was cooled to room temperature, 20 ml of the content was transferred to a porcelain container, and a sensory test was carried out for the presence or absence of suspended matter, odor and taste. ◎: Good ○: Relatively good △: Somewhat bad ×: Bad

[Thermoformability] As an evaluation of the thermoformability, the drawdown resistance and the vacuum moldability were evaluated. 1) Drawdown resistance A polyethylene resin sheet was clamped and fixed to a stainless steel fitting having an inner size of 30 cm square. The polyethylene resin sheet was heated to 210 ° C. in advance, and the polyethylene resin sheet was inserted horizontally into the oven maintained at this temperature. After the polyethylene resin sheet changes to an amorphous shape with melting, the polyethylene resin sheet's molecular orientation and melt tension cause the central portion of the polyethylene resin sheet to hang down by heating and melting from the time (T1) at which the polyethylene resin sheet is stretched, and the lower surface of the polyethylene resin sheet has a character. The measurement was performed until the time (T2) at which the tool hanged down by 15 mm from the horizontal line, and T2-T1 (sec) was determined as an index of the drawdown resistance. The higher this value, the more
There is little sag during thermoforming and molding is easy.

2) Vacuum Formability A pudding container shape (opening diameter 64 mm, bottom diameter 50 mm, depth 52 mm) was vacuum formed under the following conditions using Model FLX-02 manufactured by Asano Laboratories. Based on the appearance of the molded article, evaluation of vacuum formability such as presence or absence of wrinkles, uneven thickness, and occurrence of holes was performed. (Molding conditions) Plug assist: Yes (assist rate 43%) Upper heater temperature: 450 ° C Lower heater temperature: 450 ° C Heating time: 15 seconds Upper table delay: 1 second Upper table time: 10 seconds Lower table delay: 0.8 Second Lower table time: 10 seconds Mold temperature: 60 ° C Vacuum delay: 3 seconds Cooling time: 10 seconds Release time: 1.7 seconds

[Comprehensive Evaluation] A: Satisfies the characteristics of the sheet and is excellent in cleanliness. ：: There is no practical problem with respect to moldability and properties of the obtained polyethylene resin sheet, for example, uniformity (without unevenness), rigidity (such as elastic modulus). Δ: The polyethylene resin sheet can be formed into a sheet, but the sheet properties (elastic modulus, etc.) are insufficient. X: A polyethylene resin sheet cannot be molded.

Various components used in Examples and Comparative Examples are as follows. [(A) High-density polyethylene] HD-1: density 0.952 g / cm ³ , MFR 0.2 g
/ 10 minutes HD-2: density 0.950 g / cm ³ , MFR 0.6 g
/ 10 min HD-3: density 0.953 g / cm ³ , MFR 5 g / 1
0 min HD-4: density 0.956 g / cm ³ , MFR 12 g /
10 minutes [(C) high-pressure radical low-density polyethylene] LD: density 0.924 g / cm ³ , MFR 1.0 g
/ 10 minutes

[(B) Ethylene copolymer] The (B) ethylene copolymer was polymerized by the following method. (Preparation of solid catalyst) To a catalyst preparation device equipped with an electromagnetic induction stirrer, 1000 ml of toluene purified under nitrogen, 22 g of tetraethoxyzirconium (Zr (OEt) ₄ ) and 74 g of indene were added. 100 g of aluminum is dropped over 100 minutes,
Thereafter, the reaction was carried out at the same temperature for 2 hours. After cooling to 40 ° C., a toluene solution of methylalumoxane (concentration: 2.5 m
(mol / ml) and stirred for 2 hours.
Next, silica (manufactured by Grace, # 952, surface area: 300 m 2 / g) 2 previously calcined at 450 ° C. for 5 hours 2
After stirring at room temperature for 1 hour, nitrogen blowing and drying under reduced pressure were performed at 40 ° C. to obtain a solid catalyst having good fluidity.

(Gas Phase Polymerization) Continuous type fluidized bed gas phase polymerization apparatus
At a polymerization temperature of 80 ° C. and a total pressure of 20 kgf / cm ^Two In G
Copolymerization of ethylene and 1-hexene was performed. The solid touch
The medium is fed continuously, ethylene, 1-hexene and water
The polymerization is carried out by supplying the element so that the molar ratio is maintained at a predetermined value.
Tylene copolymer (LL-1, LL-2, LL-3) obtained
Was. The physical properties are shown in Table 1.

General metallocene-catalyzed ethylene-hexene-1 copolymer (LLDPE-4) Purified toluene was placed in a pressure reactor equipped with a stirrer and purged with nitrogen.
-Hexene was added, and a mixed solution of bis (n-butylcyclopentadienyl) zirconium dichloride and methylalumoxane (MAO) was added (Al / Zr molar ratio = 50).
After adding 0), the temperature was raised to 80 ° C. to prepare a metallocene catalyst. Then, ethylene was added, and polymerization was carried out while continuously polymerizing ethylene while maintaining the total pressure at 6 kg / cm ³ to produce an ethylene-hexene-1 copolymer (LL-4). The physical properties are shown in Table 1.

Commercial linear low density polyethylene (LL-5)
Table 1 shows the physical properties.

[0081]

[Table 1]

[Molding conditions] Molding machine: 65 mmφ extruder, L / D = 30, motor 4
5kW die: 250mmφ spiral die, lip gap:
5.0mm Molding temperature: 160-170 ° C (cylinder-die) Extrusion amount: 70-120kg / H Blow-up ratio: 2.0 Take-off speed: 0.5-2.0m / min Air ring: Multiple blowing method

[Examples 1, 3 to 8] Various resins (A), (B) and (C) each containing a predetermined amount of an antioxidant (Irganox 1076, Irgafos 168) and calcium stearate (neutralizing agent). Was dry-blended with the composition shown in Table 1, and then, under the above-mentioned molding conditions, a thickness of 0.5 mm (500 μm) to 4.0 mm by an air-cooled inflation method.
A 0 mm polyethylene resin sheet was formed. further,
Heat sealing the polyethylene resin sheet to make the content 50
A 0 ml container was produced. The obtained polyethylene resin sheet and container were evaluated. Table 2 shows the results.

Example 2 Various resins (A), (B) and (B) were mixed without adding an antioxidant and calcium stearate.
After (C) was dry-blended with the composition shown in Table 1, a polyethylene resin sheet was formed in the same manner as in Example 1. Further, the polyethylene resin sheet was heat-sealed to produce a container having an inner capacity of 500 ml. The obtained polyethylene resin sheet and container were evaluated. Table 2 shows the results.

[0085]

[Table 2]

Comparative Examples 1 to 6 Various resins (A), (B) and (C) each containing a predetermined amount of an antioxidant (Irganox 1076, Irgafos 168) and calcium stearate (neutralizing agent) After dry blending with the composition shown in Table 1, under the molding conditions shown above, a thickness of 0.5 mm (500 μm) to 2.
A 0 mm polyethylene resin sheet was formed. further,
Heat sealing the polyethylene resin sheet to make the content 50
A 0 ml container was produced. The obtained polyethylene resin sheet and container were evaluated. Table 3 shows the results. Depending on the composition, a thick (500 μm or more) polyethylene resin sheet could not be molded, or even if molded, a uniform sheet without unevenness could not be obtained.

[0087]

[Table 3]

[0088]

As described above, the polyethylene resin sheet of the present invention has (A) a density of 0.93 to 0.97 g /
98 to 55% by weight of an ethylene homopolymer or an ethylene / α-olefin copolymer in cm ³ , and (B) an ethylene copolymer 2 satisfying the above requirements (a) to (d).
And a thickness of 10%.
0 μm to 5 mm, and the elastic modulus measured according to ASTM D882 is 4500 to 12000 kgf / cm ^2.
, The tensile modulus, tensile strength, impact resistance,
It has excellent heat resistance, moldability and transparency, and can be obtained by low-temperature molding. In addition, since the polyethylene resin sheet can be obtained by low-temperature molding, it is possible to reduce additives that adversely affect a contacted object such as a content, and can be used as a packaging material for food, medical, and electronic materials. It can be suitably used for containers and the like.

Further, if the polyethylene resin sheet of the present invention is obtained by air-cooled inflation molding, the polyethylene resin sheet having no unevenness, uniform crystallization, high strength and high productivity can be obtained. . Further, the polyethylene resin sheet of the present invention has a good balance of transparency, rigidity, flexibility and the like, and thus can be suitably used as a polyethylene resin sheet for thermoforming.

The resin composition may be used in an amount of 30% by weight based on the total amount of (A) the ethylene homopolymer or the ethylene / α-olefin copolymer and (B) the ethylene copolymer.
If it further contains the ethylene polymer obtained by the following (C) high-pressure radical polymerization method, the moldability and transparency of the polyethylene resin sheet are further improved. Further, if the additive compounded in the resin composition is an additive that does not substantially migrate to the contacted object, or if the additive is not compounded in the resin composition, a clean packaging material, a container, or the like may be used. It can be used in the fields of required foods, medical care, electronic materials and the like.

The ethylene copolymer (B) further satisfies the above requirements (e) and (f).
1) If it is an ethylene copolymer, the heat resistance, hygiene, and rigidity of the polyethylene resin sheet are further improved. Further, when the ethylene copolymer (B) further satisfies the requirements (g) and (h) above (B2), the heat resistance, heat seal strength, and low temperature of the polyethylene resin sheet may be reduced. Heat sealability is further improved. Also,
The (B2) ethylene copolymer further comprises the above (i)
If the requirement is satisfied, the moldability of the polyethylene resin sheet is further improved.

The ethylene copolymer (B) is a copolymer of ethylene and α-olefin in the presence of a catalyst containing at least an organic cyclic compound having at least a conjugated double bond and a transition metal compound of Group IV of the periodic table. If it is a linear ethylene copolymer obtained by polymerization, the mechanical properties, heat sealing properties, heat blocking properties and heat resistance of the polyethylene resin sheet are further improved. Further, when the halogen concentration in the polyethylene resin sheet is 10 ppm or less, it is possible to provide a polyethylene resin sheet which is excellent in chemical stability and hygiene and is suitably used particularly in the field of food packaging materials and the like. . The molded article of the present invention is obtained by molding the polyethylene resin sheet of the present invention by any one of extrusion molding, injection molding, hollow molding, and compression molding. Excellent strength, impact resistance, heat resistance, moldability, and transparency.

The method for producing a polyethylene resin sheet of the present invention comprises the steps of: (A) a density of 0.93 to 0.97 g / cm ³
98 to 55% by weight of the ethylene homopolymer or ethylene / α-olefin copolymer of (B)
A resin composition containing 2 to 45% by weight of an ethylene copolymer satisfying the requirement (d);
Under the conditions of a molding temperature of 0 ° C. or less and a blow-up ratio of 1.2 to 3.0, a thickness of 100 μm to 5 mm, ASTM D8
The elastic modulus measured according to No. 82 is 4500 to 12000
Since it is a method of forming on a polyethylene resin sheet in the range of kgf / cm ^{2 by} the air-cooled inflation molding method, it is excellent in tensile elastic modulus, tensile strength, impact resistance, heat resistance, molding workability, transparency, and has no unevenness. A thick polyethylene resin sheet with uniform crystallization and high productivity can be obtained by low-temperature molding.

Further, in the method for producing a polyethylene resin sheet of the present invention, the additive compounded in the resin composition is an additive that does not substantially migrate to the contacted object, or the additive is added to the resin composition. If not blended, it is used in the fields of food, medicine, electronic materials, etc., where clean packaging materials and containers are required, and has tensile modulus, tensile strength, impact resistance, heat resistance, moldability, and transparency. Thus, a polyethylene resin sheet excellent in quality can be obtained. Further, in the method for producing a polyethylene resin sheet of the present invention, if a hollow tube obtained by air-cooling inflation molding of the resin composition is sandwiched and formed into a sheet, a thick sheet can be efficiently produced.

[Brief description of the drawings]

FIG. 1 is a graph showing an elution temperature-elution amount curve of an ethylene copolymer (B1) in the present invention.

FIG. 2 is a graph showing an elution temperature-elution amount curve of an ethylene copolymer with a metallocene catalyst.

FIG. 3 is a graph showing an elution temperature-elution amount curve of the (B2) ethylene copolymer in the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // (C08L 23/04 (C08L 23/04 23:08) 23:08) B29K 23:00 B29K 23: 00 B29L 7:00 B29L 7:00 F term (reference) 4F071 AA15 AA15X AA16 AA18 AA19 AA21X AA28 AA28X AA31X AA76 AB01 AF20 AF20Y AH04 AH05 BA01 BB09 BC01 4F207 AA03A AA03E AA04E AG01 AR01 AR01 AR01 AR01 AR08 KW23 4F208 AA03A AA03E AA04E AC03 AR06 AR12 AR15 AR17 AR18 AR20 LB01 LG01 LG22 LG28 MB01 MG01 MG11 MG22 MG23 MG24 4F210 AA03A AA03E AA04E AG01 AG08 AR06 AR12 AR15 AR17 AR18 AR20 QA01 QG01 BB01B03Y02 BB01YBBB BB01YB CC00Z CF06Z DE076 DE086 DE106 DE136 DE146 DE236 DG046 DG056 DJ006 DJ016 DJ036 DJ046 DJ056 DL006 FA016 FA086 FA106 FD016 GG01 G G02

Claims (14)

[Claims] (A) a density of 0.93 to 0.97 g / cm
³ of the ethylene homopolymer or an ethylene · alpha-olefin copolymer 98 to 55 wt%, (B) below (a) ~
(D) is obtained from a resin composition containing 2 to 45% by weight of an ethylene copolymer satisfying the requirements, and has a thickness of 100 μm to
A polyethylene resin sheet having a thickness of 5 mm and an elastic modulus measured in accordance with ASTM D882 in a range of 4500 to 12000 kgf / cm ² . (A) a density of 0.86 to 0.94 g / cm ³ , (b) a melt flow rate of 0.01 to 50 g / 10
(C) a molecular weight distribution (Mw / Mn) of 1.5 to 4.5; (d) a total of 25 obtained from an integrated elution curve of an elution temperature-elution amount curve by a continuous heating elution fractionation method (TREF). The difference T ₇₅ -T ₂₅ and the density d between the temperature T _{25 at} which% elutes and the temperature T _{75 at} which 75% of the total elutes satisfy the following (Equation 1): (Equation 1) T ₇₅ -T ₂₅ ≦ -670 × d + 644 2. The polyethylene resin sheet according to claim 1, obtained by air-cooled inflation molding. 3. The polyethylene resin sheet according to claim 1, which is a polyethylene resin sheet for thermoforming. 4. The resin composition according to claim 1, wherein said resin composition comprises 30% by weight based on a total amount of (A) an ethylene homopolymer or an ethylene / α-olefin copolymer and (B) an ethylene copolymer.
2. The method according to claim 1, further comprising the following (C) an ethylene polymer obtained by a high-pressure radical polymerization method.
4. The polyethylene resin sheet according to any one of claims 3 to 3. 5. The method according to claim 1, wherein the additive compounded in the resin composition is an additive which does not substantially migrate to the contacted object, or the additive is not compounded in the resin composition. 5. The polyethylene resin sheet according to any one of 1 to 4. 6. The ethylene copolymer (B1), wherein the (B) ethylene copolymer further satisfies the following requirements (e) and (f):
The polyethylene resin sheet according to any one of the above. (E) orthodichlorobenzene (ODC) at 25 ° C.
B) The soluble content X (% by weight), the density d and the melt flow rate (MFR) satisfy the relationship of the following (Formula 2) and (Formula 3) (Formula 2) d−0.008 log MFR ≧ 0.93 X <2.0 (Equation 3) d−0.008 log MFR <0.93 X <9.8 × 10 ³ × (0.9300−d + 0.008)
(logMFR) ² +2.0 (f) Presence of multiple peaks in elution temperature-elution amount curve by continuous heating elution fractionation method (TREF) 7. The ethylene copolymer (B2), wherein the ethylene copolymer (B) further satisfies the following requirements (g) and (h):
The polyethylene resin sheet according to any one of the above. (G) elution temperature by continuous Atsushi Nobori elution fractionation (TREF) - it is one peak of elution curve and the T ₇₅ -T ₂₅ and density d is, satisfy the relation of the following (Equation 4) ( (H) T ₇₅ −T ₂₅ ≧ −300 × d + 285 (h) One or two melting point peaks, and the highest melting point T _ml and density d satisfy the relationship of the following (Formula 5) ( Formula 5) T _ml ≧ 150 × d−17 8. The polyethylene resin sheet according to claim 7, wherein the (B2) ethylene copolymer further satisfies the following requirement (i). (I) Melt tension (MT) and melt flow rate (MFR) satisfy the following (Equation 6) (Equation 6) logMT ≦ −0.572 × logMFR + 0.3 9. The (B) ethylene copolymer is composed of an organic cyclic compound having at least a conjugated double bond and an organic cyclic compound (IV) in the periodic table.
Ethylene and α in the presence of a catalyst containing a group IV transition metal compound
The polyethylene resin sheet according to any one of claims 1 to 8, wherein the polyethylene resin sheet is a linear ethylene copolymer obtained by copolymerizing an olefin. 10. The polyethylene resin sheet according to claim 1, wherein the halogen concentration in the polyethylene resin sheet is 10 ppm or less. 11. The polyethylene resin sheet according to claim 1, wherein the polyethylene resin sheet is an extrusion molding method, an injection molding method,
A molded article obtained by molding by any one of a hollow molding method, a compression molding method and a thermoforming method. 12. (A) Density 0.93 to 0.97 g / c
ethylene homopolymer or an ethylene · alpha-olefin copolymer 98 to 55 wt% of m ^3, (B) below (a) ~
A resin composition containing 2 to 45% by weight of an ethylene copolymer satisfying the requirement (d);
Under the conditions of a molding temperature of 0 ° C. or less and a blow-up ratio of 1.2 to 3.0, a thickness of 100 μm to 5 mm, ASTM D8
The elastic modulus measured according to No. 82 is 4500 to 12000
A method for producing a polyethylene resin sheet, comprising forming a polyethylene resin sheet having a range of kgf / cm ² by an air-cooled inflation molding method. (A) a density of 0.86 to 0.94 g / cm ³ , (b) a melt flow rate of 0.01 to 50 g / 10 min, (c)
Molecular weight distribution (Mw / Mn) of 1.5 to 4.5, (d) Temperature at which 25% of the whole is eluted from the integrated elution curve of elution temperature-elution amount curve by continuous heating elution fractionation method (TREF) Difference T ₇₅ between T ₂₅ and temperature T _{75 at} which 75% of the whole elutes
−T ₂₅ and density d satisfy the relationship of the following (formula 1) (formula 1) T ₇₅ −T ₂₅ ≦ −670 × d + 644 13. The method according to claim 1, wherein the additive compounded in the resin composition is an additive which does not substantially migrate to the contacted object, or the additive is not compounded in the resin composition. 13. The method for producing a polyethylene resin sheet according to item 12. 14. The sheet according to claim 12, wherein a hollow tube obtained by air-cooling inflation molding of the resin composition is sandwiched and crushed to form a sheet.
The method for producing a polyethylene resin sheet according to the above.