阅读说明：本技术 乙烯类聚合物、乙烯类聚合物的制造方法和膜 (Ethylene polymer, method for producing ethylene polymer, and film ) 是由 美浓贵之 真见俊彦 一宫宜也 于 2021-06-22 设计创作，主要内容包括：本发明涉及乙烯类聚合物、乙烯类聚合物的制造方法和膜。本发明的课题在于提供一种能够得到减少了厚度不均的膜的乙烯类聚合物、该乙烯类聚合物的制造方法和含有所述乙烯类聚合物的膜。本发明的乙烯类聚合物满足下式(1)和(2)：0.362≤ηL～(1256％)/ηL～(10％)≤0.466(1)0.0282≤I5～(2506％)/I1～(2506％)≤0.0328(2)。(The invention relates toVinyl polymer, process for producing vinyl polymer, and film. The invention provides an ethylene polymer capable of obtaining a film with reduced thickness unevenness, a method for producing the ethylene polymer, and a film containing the ethylene polymer. The ethylene polymer of the present invention satisfies the following formulae (1) and (2): eta L of 0.362 ≤ 1256％ /ηL 10％ ≤0.466(1)0.0282≤I5 2506％ /I1 2506％ ≤0.0328(2)。)

1. An ethylene-based polymer, wherein the ethylene-based polymer satisfies the following formulae (1) and (2):

0.362≤ηL^1256％/ηL^10％≤0.466 (1)

in the formula (I), the compound is shown in the specification,

ηL^10％the strain γ of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀Viscosity at the fastest shear rate (Pa · s) at 10%;

ηL^1256％the strain γ of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀1256% of viscosity (Pa.s) at the highest shear rate,

0.0282≤I5^2506％/I1^2506％≤0.0328 (2)

in the formula (I), the compound is shown in the specification,

I1^2506％shows the strain gamma of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀The intensity of the first harmonic obtained by fourier transform of the response stress at 2506%;

I5^2506％shows the strain gamma of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀The intensity of the fifth harmonic obtained by fourier transform of the response stress at 2506%.

2. The ethylene-based polymer of claim 1, wherein the ethylene-based polymer satisfies the following formulae (1 ') and (2'):

0.370≤ηL^1256％/ηL^10％≤0.466 (1’)

0.0282≤I5^2506％/I1^2506％≤0.0320 (2’)。

3. the ethylene-based polymer of claim 1 or 2, wherein the ethylene-based polymer satisfies the following formulae (1 ") and (2"):

0.370≤ηL^1256％/ηL^10％≤0.440 (1”)

0.0300≤I5^2506％/I1^2506％≤0.0320 (2”)。

4. the ethylene-based polymer according to any one of claims 1 to 3, wherein the ethylene-based polymer has a crosslinked structure.

5. The ethylene-based polymer of any one of claims 1 to 4, wherein the ethylene-based polymer is a high pressure process low density polyethylene.

6. The ethylene-based polymer according to any one of claims 1 to 5, wherein the melt flow rate of the ethylene-based polymer measured at a temperature of 190 ℃ under a load of 2.16kg is 2g/10 min or more and 6g/10 min or less.

7. A process for producing an ethylene polymer according to any one of claims 1 to 6, wherein,

the method for producing an ethylene polymer comprises the steps of:

a step (A) in which a mixture comprising an ethylene polymer and a radical initiator is heated at a temperature T^AMelt-kneading at a temperature of (DEG C);

a step (B) of subjecting the melt-kneaded product obtained in the step (A) to a temperature T^BMelt-kneading at a temperature of (DEG C); and

a step (C) of subjecting the melt-kneaded product obtained in the step (B) to a temperature T^CMelt-kneading at (. degree. C.) and

satisfies the following formula (11):

T^A<T^B<T^C (11)。

8. the process for producing an ethylene-based polymer according to claim 7, wherein,

the step (A) is a step of melt-kneading the mixture using a melt-kneading extruder (a),

the step (B) is a step of melt-kneading the mixture using a melt-kneading extruder (B),

the step (C) is a step of melt-kneading the mixture using a melt-kneading extruder (C), and

the melt-kneading extruder (a), the melt-kneading extruder (b) and the melt-kneading extruder (c) are different from each other.

9. The process for producing an ethylene-based polymer according to claim 7 or 8, wherein the step (A) is a step of melt-kneading a mixture comprising an ethylene-based polymer and a radical initiator with the ethylene-based polymer.

10. The process for producing an ethylene-based polymer according to any one of claims 7 to 9, wherein the radical initiator is a peroxide.

11. A film comprising the ethylene-based polymer according to any one of claims 1 to 6.

Technical Field

The present invention relates to an ethylene-based polymer, a method for producing the ethylene-based polymer, and a film containing the ethylene-based polymer.

Background

Conventionally, as a film for packaging foods and the like, a laminated film obtained by laminating (laminating) a base film and a film made of an ethylene polymer by melt-extruding a resin composition containing the ethylene polymer on the base film has been widely used. Such a film made of an ethylene polymer is suitably used as a sealing layer when used on the surface of a laminate film and as an adhesive layer when used inside a laminate film, and therefore excellent transparency and adhesive strength are required.

As a material of an ethylene polymer used for a laminate film, for example, patent document 1 discloses a polyethylene resin material for lamination, which is modified by adding 0.001 to 1.0 part by weight of a radical initiator to 100 parts by weight of a polyethylene resin composition containing: 5 to 95 weight percent of polyethylene resin by high pressure free radical polymerization and 95 to 5 weight percent of polyethylene resin by high pressure free radical polymerization except the polyethylene resin.

Documents of the prior art

Patent document

[ patent document 1] Japanese patent application laid-open No. 2010-144134

Disclosure of Invention

Problems to be solved by the invention

Incidentally, in order to improve transparency and adhesive strength, it is required to reduce thickness unevenness of a film made of a vinyl polymer and improve flatness. However, the film made of the ethylene polymer of patent document 1 has a problem of large thickness unevenness.

The present invention has been made in view of the above problems, and an object thereof is to provide an ethylene polymer capable of obtaining a film with reduced thickness unevenness, a method for producing the ethylene polymer, and a film containing the ethylene polymer.

Means for solving the problems

The ethylene polymer of the present invention satisfies the following formulae (1) and (2):

0.362≤ηL^1256％/ηL^10％≤0.466 (1)

(in the formula, wherein,

ηL^10％the strain γ of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀Viscosity at the fastest shear rate (Pa · s) at 10%;

ηL^1256％the strain γ of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀1256% is the viscosity at which the shear rate is the fastest (Pa · s). )

0.0282≤I5^2506％/I1^2506％≤0.0328 (2)

(in the formula, wherein,

I1^2506％shows the strain gamma of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀The intensity of the first harmonic obtained by fourier transform of the response stress at 2506%;

I5^2506％shows the strain gamma of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀The intensity of the fifth harmonic obtained by fourier transform of the response stress at 2506%. ).

The method for producing an ethylene polymer of the present invention is a method for producing the ethylene polymer, and the method for producing an ethylene polymer comprises the steps of: a step (A) in which a mixture comprising an ethylene polymer and a radical initiator is heated at a temperature T^AMelt-kneading at a temperature of (DEG C); a step (B) of subjecting the melt-kneaded product obtained in the step (A) to a temperature T^BMelt-kneading at a temperature of (DEG C); and a step (C) of subjecting the melt-kneaded product obtained in the step (B) to a temperature T^CMelt-kneading at (. degree. C.) and satisfying the following formula (11):

T^A<T^B<T^C (11)。

the film of the present invention contains the above-mentioned ethylene polymer.

Effects of the invention

According to the present invention, there can be provided an ethylene-based polymer capable of giving a film with reduced thickness unevenness, a method for producing the ethylene-based polymer, and a film containing the ethylene-based polymer.

Detailed Description

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

< ethylene Polymer >

The ethylene polymer of the present embodiment satisfies the following formulae (1) and (2):

0.362≤ηL^1256％/ηL^10％≤0.466 (1)

(in the formula, wherein,

ηL^10％the strain γ of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀Viscosity at the fastest shear rate (Pa · s) at 10%;

ηL^1256％the strain γ of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀1256% is the viscosity at which the shear rate is the fastest (Pa · s). )

0.0282≤I5^2506％/I1^2506％≤0.0328 (2)

(in the formula, wherein,

I1^2506％shows the strain gamma of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀The intensity of the first harmonic obtained by fourier transform of the response stress at 2506%;

I5^2506％shows the strain gamma of an ethylene polymer measured by the LAOS method at 150 ℃ and 0.05Hz₀The intensity of the fifth harmonic obtained by fourier transform of the response stress at 2506%. ).

Here, the LAOS (large amplitude oscillatory shear) method refers to a method of applying a large and fast shear strain to a sample and observing and analyzing a response stress.

η L is a value obtained by applying a shear strain (deformation) of a sine wave to a sample, plotting a deformation rate and a response stress to create a lissajous curve, and dividing the response stress at the time of the fastest deformation rate by the deformation rate at that time, i.e., η L is viscosity. While changing the shearWhen the η L is measured along with the magnitude of strain (deformation), a change occurs according to the structure of the ethylene polymer. Specifically, when shear strain (deformation) is increased, the ethylene-based polymer is oriented in the shear direction (deformation direction), and therefore η L decreases. The degree of decrease in η L varies depending on the ease with which the ethylene-based polymer is oriented in the shear direction (deformation direction). If the ethylene polymer is not easily oriented in the shear direction (deformation direction), it means a state in which the ethylene polymer is entangled and is not easily moved, so it can be said that η L^1256％/ηL^10％Is a parameter that reflects the amount of entangled branch structure.

About eta L^10％The shear strain of a 0.05Hz sine wave was applied to the sample for 6 cycles, and the average value of the last 3 cycles was defined as the measured value. Eta L^10％The time required for the measurement of (2) is usually 120 seconds.

About eta L^1256％The shear strain of a 0.05Hz sine wave was applied to the sample for 6 cycles, and the average value of the last 3 cycles was defined as the measured value. Eta L^1256％The time required for the measurement of (2) is usually 120 seconds.

Generally, η L is performed first^10％And in the stepwise increase of the strain gamma₀Simultaneously, eta L was measured. Specifically, the strain γ is₀10% -100% is divided into 10 stages of equal logarithmic spacing (i.e. gamma. is increased₀η L was measured while being 10%, 13%, 16%, 20%, 25%, 32%, 40%, 50%, 63%, 79%, 100%). Similarly, the strain γ is measured₀Eta L is measured while dividing 100% to 1000% into 10 steps of equal logarithmic intervals, and gamma is measured₀η L was measured while dividing 1000% to 10000% into 10 steps of equal logarithmic intervals. As described above, the time required for one measurement of η L is usually 120 seconds.

In the method for producing an ethylene polymer described later, η L can be increased by increasing the amount of the radical initiator to more than 0.03 mass%^1256％/ηL^10％And by reducing the amount of the radical initiator to be blendedDecrease of η L at 0.03 mass%^1256％/ηL^10％The value of (c).

The ratio of the intensity of the fifth harmonic to the intensity of the first harmonic (I5/I1) varies depending on the structure of the vinyl polymer. Specifically, the greater the distribution of the entangled branched structures of the ethylenic polymer (offset (meta り)), the greater the I5/I1 tends to be. Therefore, I5 is considered^2506％/I1^2506％Is a parameter reflecting the distribution (bias) of the entangled branch structure.

With respect to strain gamma₀In the measurement of the response stress at 2506%, a shear strain of a 0.05Hz sine wave was applied to the sample for 6 cycles, and the average value of the latter 3 cycles was used as the measurement value. Strain gamma₀The time required for measurement of the response stress at 2506% is usually 120 seconds.

As described above, generally, the strain γ is performed first₀Measurement of response stress at 10%, and gradual increase of strain γ₀And simultaneously measuring the response stress. Specifically, the strain γ is₀The response stress is measured while 10% to 100%, 100% to 1000%, 1000% to 10000% are increased in 10 stages of equal logarithmic intervals. As described above, the time required for the measurement of the one-time response stress is generally 120 seconds.

In the process for producing an ethylene polymer described later, the temperature T can be controlled^CIncreasing I5 above 210 deg.C^2506％/I1^2506％And can be determined by letting the temperature T^CReduction of I5 below 210 deg.C^2506％/I1^2506％The value of (c).

From the viewpoint of further reducing the thickness unevenness of the film, the ethylene-based polymer of the present embodiment preferably satisfies the following formulas (1 ') and (2'), and more preferably satisfies the following formulas (1 ") and (2").

0.370≤ηL^1256％/ηL^10％≤0.466 (1’)

0.370≤ηL^1256％/ηL^10％≤0.440 (1”)

0.0282≤I5^2506％/I1^2506％≤0.0320 (2’)

0.0300≤I5^2506％/I1^2506％≤0.0320 (2”)

From the viewpoint of processing stability, the Melt Flow Rate (MFR) of the ethylene polymer of the present embodiment measured under the conditions of a temperature of 190 ℃ and a load of 2.16kg is preferably 2g/10 min to 6g/10 min, more preferably 3g/10 min to 5g/10 min. Incidentally, MFR was measured under the conditions of a temperature of 190 ℃ and a load of 2.16kg according to method A defined in JIS K7210-1.

From the viewpoint of processing stability, the molecular weight distribution of the ethylene-based polymer of the present embodiment is preferably 3 or more and 15 or less, and more preferably 5 or more and 13 or less. The molecular weight distribution is a ratio (Mw/Mn) of a weight average molecular weight Mw in terms of polystyrene to a number average molecular weight Mn in terms of polystyrene, measured by a Gel Permeation Chromatography (GPC) method.

GPC measurement was carried out under the following conditions, and a base line on the chromatogram was defined based on the description of ISO16014-1 and a peak was designated.

(measurement conditions)

The device comprises the following steps: HLC-8121GPC/HT (manufactured by Tosoh corporation)

GPC column: TOSOH TSKgel GMH6-HT 3 pieces with inner diameter of 7.8mm × 300mm (manufactured by Tosoh corporation)

Mobile phase: 0.1w/V BHT was added to o-dichlorobenzene (Wako pure chemical industries, Ltd., Special grade) and used

Flow rate: 1 mL/min

Column oven temperature: 140 deg.C

And (3) detection: differential Refractive Index Detector (RID)

RID cell temperature: 140 deg.C

Injection amount of sample solution: 300 μ L

Concentration of sample solution: 1mg/mL

Standard for GPC column calibration: prepared by the following method: standard polystyrene manufactured by Tosoh corporation was measured in the combinations shown in Table 1 below, and 5mL of o-dichlorobenzene (same composition as the mobile phase) was added to each combination and dissolved at room temperature.

TABLE 1

Combination 1	F700 0.4mg	F20 0.9mg	A5000 1.2mg
				Combination 2	F288 0.4mg	F10 1.0mg	A2500 1.2mg
Combination 3	F80 0.7mg	F4 1.1mg	A1000 1.3mg
				Combination 4	F40 0.8mg	F2 1.1mg	A500 1.3mg

From the viewpoint of further reducing the thickness unevenness of the film, the ethylene-based polymer of the present embodiment preferably has a crosslinked structure.

In addition, the ethylene polymer of the present embodiment is preferably high-pressure low-density polyethylene from the viewpoint of further reducing the thickness unevenness of the film.

High pressure process low density polyethylene is low density polyethylene produced by a high pressure free radical polymerization process. Generally, a high-pressure low-density polyethylene is produced by continuously polymerizing ethylene monomer at 150 to 300 ℃ in the presence of oxygen or an organic peroxide as a polymerization initiator in a pressure-resistant polymerization reactor under a pressure of 1000 to 2500 atm.

From the viewpoint of reducing the extrusion load during film formation, the MFR of the high-pressure low-density polyethylene is preferably 4g/10 min to 30g/10 min, more preferably 6g/10 min to 30g/10 min, and still more preferably 6g/10 min to 25g/10 min.

The density of the high-pressure low-density polyethylene is preferably 910kg/m³Above 930kg/m³Hereinafter, 912kg/m is more preferable³Above 925kg/m³More preferably 915kg/m³Above and 920kg/m³The following. The density was measured according to the method defined by method A in JIS K7112-1980 after annealing as described in JIS K6760-1995.

The molecular weight distribution of the high-pressure low-density polyethylene is preferably 5.0 or more and 15.0 or less, and more preferably 7.0 or more and 10.0 or less.

The Melt Flow Rate Ratio (MFRR) of the high-pressure low-density polyethylene is preferably 25 or more and less than 60, more preferably 30 or more and 45 or less. Incidentally, the MFRR means the ratio of H-MFR to MFR. The H-MFR was measured at 190 ℃ under a load of 21.60kg according to method A defined in JIS K7210-1.

The ethylene-based polymer of the present embodiment may be an ethylene-vinyl acetate copolymer. The ethylene-vinyl acetate copolymer is a copolymer having an ethylene-based monomer unit and a vinyl acetate-based monomer unit.

The MFR of the ethylene-vinyl acetate copolymer is preferably 10g/10 min or more and 30g/10 min or less, and more preferably 15g/10 min or more and 25g/10 min or less.

The content of the vinyl acetate-based monomer unit contained in the ethylene-vinyl acetate copolymer is preferably 10 mass% or more and 30 mass% or less, and more preferably 15 mass% or more and 25 mass% or less, with respect to 100 mass% of the ethylene-vinyl acetate copolymer.

The molecular weight distribution of the ethylene-vinyl acetate copolymer is preferably 3.0 or more and 7.0 or less, and more preferably 3.5 or more and 5.0 or less.

The MFRR of the ethylene-vinyl acetate copolymer is preferably 25 or more and 60 or less, and more preferably 30 or more and 50 or less.

Examples of the method for producing the ethylene-vinyl acetate copolymer include: a high pressure radical polymerization process for copolymerizing ethylene and vinyl acetate in the presence of a radical initiator, under conditions of 50MPa to 400MPa, 100 ℃ to 300 ℃, in the presence or absence of a suitable solvent or chain transfer agent. The MFR or molecular weight distribution of the ethylene-vinyl acetate copolymer, or the content of vinyl acetate-based monomer units in the ethylene-vinyl acetate copolymer, can be controlled by adjusting the polymerization conditions of the high-pressure radical polymerization.

The ethylene-based polymer of the present embodiment may contain a thermoplastic resin and a thermoplastic elastomer different from the above-described high-pressure low-density polyethylene and ethylene-vinyl acetate copolymer.

Examples of the thermoplastic resin and thermoplastic elastomer different from the high-pressure low-density polyethylene and the ethylene-vinyl acetate copolymer include: linear low density polyethylene, ultra-low density polyethylene, ethylene- α -olefin copolymer, ethylene- (meth) acrylic acid copolymer, metal salt of ethylene- (meth) acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer rubber, and the like.

The content of the thermoplastic resin and the thermoplastic elastomer different from the high-pressure low-density polyethylene and the ethylene-vinyl acetate copolymer is preferably 5% by mass or less, and more preferably 2% by mass or less, relative to 100% by mass of the total mass of the resin components contained in the ethylene-based polymer of the present embodiment.

The ethylene polymer of the present embodiment may contain additives such as an antioxidant, a lubricant, an antistatic agent, a processability improver, an anti-blocking agent, a weather resistant stabilizer, a mold release agent, a flame retardant, a metal soap, a wax, an antifungal agent, an antibacterial agent, a filler, and a foaming agent, as required.

Examples of the antioxidant include: phenol stabilizers such as 2, 6-di-t-butyl-p-cresol (BHT), tetrakis [ methylene-3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate ] methane (product name: IRGANOX (registered trademark) 1010, manufactured by Ciba specialty Chemicals), and n-octadecyl 3- (4 ' -hydroxy-3 ', 5 ' -di-t-butylphenyl) propionate (product name: IRGANOX (registered trademark) 1076, manufactured by Ciba specialty Chemicals); phosphite stabilizers such as pentaerythritol diphosphite bis (2, 4-di-t-butylphenyl) ester or tris (2, 4-di-t-butylphenyl) phosphite; and a phenol phosphite bifunctional stabilizer such as 6- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propoxy ] -2,4,8, 10-tetra-tert-butyldibenzo [ d, f ] [1,3,2] dioxaphosphepin (product name: Sumilizer (registered trademark) GP, manufactured by Sumitomo chemical Co., Ltd.). The content of the antioxidant is preferably 0.001 mass% or more and 1 mass% or less, and more preferably 0.01 mass% or more and 0.1 mass% or less, relative to 100 mass% of the total mass of the ethylene-based polymer.

Examples of the lubricant include: erucamide, higher fatty acid amides, higher fatty acid esters, and the like. The content of the lubricant is preferably 0.01 mass% or more and 1 mass% or less, and more preferably 0.05 mass% or more and 0.5 mass% or less, based on 100 mass% of the total mass of the ethylene-based polymer.

Examples of the antistatic agent include: and glycerol esters, sorbitan acid esters, polyethylene glycol esters of fatty acids having 8 to 22 carbon atoms. The content of the antistatic agent is preferably 0.01 to 1% by mass, more preferably 0.1 to 0.5% by mass, based on 100% by mass of the total mass of the ethylene polymer.

Examples of the processability improver include: fatty acid metal salts such as calcium stearate. The content of the processability improver is preferably 0.01% by mass or more and 1% by mass or less, more preferably 0.1% by mass or more and 0.5% by mass or less, relative to 100% by mass of the total mass of the ethylene polymer.

Examples of the antiblocking agent include: silica, diatomaceous earth, calcium carbonate, talc, and the like. The content of the antiblocking agent is preferably 0.1 mass% or more and 5 mass% or less, more preferably 0.3 mass% or more and 3 mass% or less, based on 100 mass% of the total mass of the ethylene polymer.

These additives may be added to the ethylene polymer, or a master batch obtained by adding the additives to the ethylene polymer may be mixed with the ethylene polymer. When two or more kinds of ethylene polymers are contained, the additives may be added after mixing two or more kinds of ethylene polymers in advance, or the additives may be added to one kind of ethylene polymer, or the additives may be added to the respective ethylene polymers separately.

< Process for producing ethylene-based Polymer >

The method for producing an ethylene polymer according to the present embodiment is a method for producing the ethylene polymer, and the method for producing an ethylene polymer includes the steps of: a step (A) in which a mixture comprising an ethylene polymer and a radical initiator is heated at a temperature T^AMelt-kneading at a temperature of (DEG C); a step (B) of subjecting the melt-kneaded product obtained in the step (A) to a temperature T^BMelt-kneading at a temperature of (DEG C); and a step (C) of subjecting the melt-kneaded product obtained in the step (B) to a temperature T^CMelt-kneading at (. degree. C.) and satisfying the following formula (11):

T^A<T^B<T^C (11)。

as the ethylene polymer contained in the mixture, various ethylene polymers such as the above-mentioned high-pressure low-density polyethylene, ethylene-vinyl acetate copolymer, linear low-density polyethylene, ultra-low-density polyethylene, ethylene- α -olefin copolymer, ethylene- (meth) acrylic acid copolymer, metal salt of ethylene- (meth) acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer rubber and the like can be used.

The radical initiator contained in the mixture is preferably a peroxide, and more preferably a cyclic organic peroxide represented by the following formula (I).

Wherein R is¹～R⁶Independently represents an alkyl group having 1 to 12 carbon atoms, a phenyl group or an alkyl-substituted phenyl group. Wherein R is¹～R⁶Preferably independently an alkyl group having 1 to 12 carbon atoms. In addition, in R¹～R⁶Among them, R is more preferable¹～R³Is an alkyl group having the same structure, and R⁴～R⁶As the alkyl group having the same structure, R is more preferable¹～R³Is methyl, and R⁴～R⁶Is ethyl.

The radical initiator may also be an organic peroxide other than the cyclic organic peroxide represented by formula (I). As the organic peroxide other than the cyclic organic peroxide represented by the formula (I), for example, there can be mentioned: dicumyl peroxide, di-tert-butyl peroxide, 2, 5-dimethyl-2, 5-di (tert-butylperoxy) hexane, 2, 5-dimethyl-2, 5-di (tert-butylperoxy) -3-hexyne, 1, 3-bis (tert-butylperoxyisopropyl) benzene, 1-bis (tert-butylperoxy) -3,3, 5-trimethylcyclohexane, n-butyl 4, 4-bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2, 4-dichlorobenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropylcarbonate, diacetyl peroxide, lauroyl peroxide, cumyl tert-butyl peroxide, and the like. These organic peroxides may be used alone or in combination of two or more. Among them, 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexane is preferable from the viewpoint of ease of handling.

The amount of the radical initiator to be blended is preferably 0.03 mass% or more, more preferably 0.04 mass% or more, and further preferably 0.05 mass% or more, with respect to 100 mass% of the total amount of the ethylene polymer contained in the mixture, from the viewpoint of the strength of the molded article, and is preferably 0.5 mass% or less, more preferably 0.4 mass% or less, and further preferably 0.3 mass% or less, from the viewpoint of the fluidity.

Temperature T^APreferably 95 ℃ to 130 ℃, more preferably 100 ℃ to 125 ℃, and still more preferably 105 ℃ to 120 ℃. Temperature T^BThe half-life of the radical initiator is preferably a temperature exceeding 1 minute, and specifically, preferably 130 ℃ or more and 180 ℃ or less, more preferably 135 ℃ or more and 175 ℃ or less, and further preferably 140 ℃ or more and 170 ℃ or less. Temperature T^CThe half-life of the radical initiator is preferably 1 minute or less, and specifically, from the viewpoint of productivity, it is preferably 210 ℃ or more and 320 ℃ or less, more preferably 220 ℃ or more and 310 ℃ or less, and still more preferably 230 ℃ or more and 300 ℃ or less.

From the viewpoint of uniform dispersibility, at the temperature T^AThe time for melt kneading at (. degree. C.) is preferably 0.1 minute or more, more preferably 0.5 minute or more, and from the viewpoint of productivity, is preferably 30 minutes or less, more preferably 20 minutes or less. From the viewpoint of uniform dispersibility, at the temperature T^BThe time for melt kneading at (. degree. C.) is preferably 0.1 minute or more, more preferably 0.5 minute or more, and from the viewpoint of productivity, is preferably 30 minutes or less, more preferably 20 minutes or less. At a temperature T^CThe time for melt kneading at (. degree. C.) is usually a time equal to or longer than the half-life of the organic peroxide, and specifically, from the viewpoint of the strength of the molded article, it is preferably 0.1 minute or longer, more preferably 0.5 minute or longer, and from the viewpoint of fluidity, it is preferably 30 minutes or shorter, more preferably 20 minutes or shorter.

The melt-kneaded product obtained in each step is preferably a pellet.

As the apparatus for melt kneading, known apparatuses such as various mixers including a single screw extruder, a twin screw extruder, an open type mixing roll, a non-open type banbury mixer, a heating roll, and a kneader can be used. In the melt-kneading, all the components to be kneaded may be melt-kneaded at once, or after a part of the components are kneaded, components not selected may be added and melt-kneaded.

In the method for producing an ethylene polymer according to the present embodiment, it is preferable that the step (a) is a step of melt-kneading using a melt-kneading extruder (a), the step (B) is a step of melt-kneading using a melt-kneading extruder (B), and the step (C) is a step of melt-kneading using a melt-kneading extruder (C), and the melt-kneading extruder (a), the melt-kneading extruder (B), and the melt-kneading extruder (C) are different from each other. With this configuration, the operability can be improved.

The same melt kneading extruder may be used in any two of the step (a), the step (B) and the step (C), or the same melt kneading extruder may be used in all of the step (a), the step (B) and the step (C). When the same melt-kneading extruder is used, a plurality of steps can be performed by gradually changing the melt-kneading temperature in the melt-kneading extruder.

< film >

The film of the present embodiment contains the above-mentioned ethylene polymer.

The film of the present embodiment is a multilayer film having a base film and a film made of the above-mentioned ethylene polymer. The substrate film may be one or two or more substrate films.

Examples of the substrate film include: films comprising polyamide resins such as nylon 6 and nylon 66, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, cellophane, paper, cardboard, woven fabric, aluminum foil, stretched polypropylene, polyethylene, and the like. The substrate film may have an anchor coating. The substrate film having two or more layers is obtained by laminating the respective layers by dry lamination or extrusion lamination.

Examples of the method for producing the multilayer film include: a method of melt-extruding a resin composition containing the above ethylene polymer onto a substrate film and extrusion-laminating the same. By the extrusion lamination process, a multilayer film can be produced without molding defects such as edge breakage (ear cut れ) or film breakage. Therefore, the film of the present embodiment has excellent film formability. The edge breakage is a phenomenon in which a molten film containing an ethylene polymer is broken during extrusion lamination processing. The film breakage refers to a phenomenon in which a long hole is generated in the machine direction (MD direction) in a part of a molten film containing a vinyl polymer and a part not laminated is generated.

The film made of the ethylene polymer in the multilayer film is a seal layer when used on the surface of the multilayer film, and an adhesive layer when used inside the film. In addition, in the case where the ethylene polymer-containing resin composition is laminated on the substrate film by extrusion lamination, the ethylene polymer-containing resin composition may be coated on the anchor coat layer of the substrate film.

The thickness of the film of the present embodiment is preferably 3 μm or more and 500 μm or less, and more preferably 5 μm or more and 300 μm or less.

The ethylene-based polymer, the method for producing the ethylene-based polymer, and the film according to the present embodiment are not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention. In addition, configurations, methods, and the like of embodiments other than those described above may be arbitrarily combined, and configurations, methods, and the like of one embodiment described above may be applied to configurations, methods, and the like of the other embodiments described above.

[ examples ]

The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

< melt flow Rate (MFR, Unit: g/10 min) >

Measured by the method A under the conditions of a temperature of 190 ℃ and a load of 2.16kg according to the method specified in JIS K7210-1.

< example 1>

20 parts by mass of a radical initiator (Trigonox 301, manufactured by Noneron chemical Co., Ltd.) was immersed in 80 parts by mass of a pulverized powder of a vinyl polymer (FLO-THENE FG801NN, manufactured by Sumitomo Seiko Seisakusho K.K.). The obtained impregnated powder was melt-kneaded at 110 ℃ for 1 minute using a melt-kneading extruder (a) having a screw diameter of 30mm (manufactured by UNIPLAS), to thereby prepare master batch pellets (hereinafter, also referred to as MB pellets).

The MB pellets obtained above were added to 100 parts by mass of an ethylene polymer (SUMIKA THENE CE4506, manufactured by Sumitomo chemical Co., Ltd.) so that the concentration thereof became 5800ppm, and the mixture was melt-kneaded at 150 ℃ for 1 minute using a melt-kneading extruder (b) (manufactured by Takeda Plastic machinery Co., Ltd.) having a screw diameter of 40mm, thereby obtaining pellets. The obtained pellets were melt-kneaded at 240 ℃ for 1 minute using another melt-kneading extruder (c) having a screw diameter of 40mm (manufactured by Takeda plastics mechanical Co., Ltd.), to obtain pellets.

The pellets obtained above were allowed to stand at 150 ℃ for 5 minutes (preheating step), pressurized at 150 ℃ under 5MPa for 5 minutes (pressing step), and slowly cooled at 25 ℃ for 5 minutes (slow cooling step), to obtain a compressed tablet having a thickness of 0.5 mm. From the obtained pressed sheet, a circular piece having a diameter of 8mm was punched out, to thereby prepare a measurement sample. The obtained measurement sample was measured by the LAOS method using a dynamic viscoelasticity measuring apparatus (ARES-G2, manufactured by TA instruments).

For the measurement sample, the strain γ was measured at a temperature of 150 ℃ and a frequency of 0.05Hz₀Viscosity η L at the fastest shear rate at 10%^10％And strain gamma₀1256% viscosity η L at the fastest shear rate^1256％. About eta L^10％And eta.L of^1256％The shear strain of a 0.05Hz sine wave was applied to each measurement sample for 6 cycles, and the average value of the last 3 cycles was defined as the measurement value. In addition, eta L is firstly carried out^10％And in measuring the strain gamma₀Eta L is performed while 10-100%, 100-1000%, 1000-10000% of the total amount is increased in 10 stages with equal logarithmic intervals^1256％The measurement of (1). Ratio of η L^1256％/ηL^10％Is 0.430, and satisfies the formula (1).

In addition, the strain γ of the test sample was measured at 150 ℃ and a frequency of 0.05Hz₀The response stress at 2506% was Fourier transformed (TA instruments, software name: TRIOS version)This 5.0.0) intensity of the first harmonic I1^2506％And the intensity of the fifth harmonic I5^2506％. About I1^2506％Measurement of (2) and I5^2506％The shear strain of a 0.05Hz sine wave was applied to each measurement sample for 6 cycles, and the average value of the last 3 cycles was defined as the measurement value. In addition, the strain gamma is firstly carried out₀Measurement of response stress at 10%, and₀the response stress is measured while the response stress is increased in 10 stages at equal logarithmic intervals, each of 10% to 100%, 100% to 1000%, and 1000% to 10000%. Ratio I5 thereof^2506％/I1^2506％Is 0.0308, and satisfies formula (2). The results are shown in table 2.

The pellets thus obtained were extrusion-laminated on a PET substrate having a thickness of 12 μm using a coextrusion laminator (manufactured by Sumitomo heavy mechanical Morden Co., Ltd.) having a T-die with a width of 800mm at the tip of an extruder with a screw diameter of 65mm, and under conditions such that the internal width of the T-die was 500mm, the air gap was 140mm, the lamination thickness of the ethylene polymer was 7 μm, the temperature immediately below the T-die was 333 ℃ and the lamination speed was 150 m/min. The thickness of the vinyl polymer layer 200mm wide at the center of the laminate was measured in the width direction using a desktop off-line thickness meter (TOF-5R 01, manufactured by Shanghai electric Co., Ltd.). The standard deviation of the obtained measurement values was 0.67. The results are shown in table 2.

< example 2>

MB pellets were produced in the same manner as in example 1. The MB pellets obtained above were added so that the concentration thereof became 2900ppm with respect to 100 parts by mass of the ethylene polymer (SUMIKA THENE CE4506, manufactured by Sumitomo chemical Co., Ltd.), and melt-kneaded at 150 ℃ using a melt-kneading extruder (b) (manufactured by Takeda Plastic machinery Co., Ltd.) having a screw diameter of 40mm, thereby obtaining pellets. The obtained pellets were melt-kneaded at 240 ℃ using another melt-kneading extruder (c) having a screw diameter of 40mm (manufactured by Takeda plastics mechanical Co., Ltd.), to obtain pellets.

Using the pellets thus obtained, the same procedure as in example 1 was repeatedEta L is measured by using LAOS method^1256％/ηL^10％As a result, it was 0.383, and formula (1) was satisfied. In addition, I5 was measured^2506％/I1^2506％As a result, it was 0.0313, which satisfies the formula (2). The results are shown in table 2.

Using the pellets thus obtained, an extrusion-laminated sample was produced in the same manner as in example 1, and the thickness of the laminated layer of the ethylene-based polymer having a width of 200mm at the center in the width direction was measured. The standard deviation of the obtained measurement values was 0.83.

< example 3>

MB pellets were produced in the same manner as in example 1. The MB pellets obtained above were added to 100 parts by mass of an ethylene polymer (SUMIKA THENE CE3049, manufactured by Sumitomo chemical Co., Ltd.) so that the concentration thereof became 500ppm, and melt-kneaded at 150 ℃ using a melt-kneading extruder (b) (manufactured by Takeda Plastic machinery Co., Ltd.) having a screw diameter of 40mm, thereby obtaining pellets. The obtained pellets were melt-kneaded at 240 ℃ using another melt-kneading extruder (c) having a screw diameter of 40mm (manufactured by Takeda plastics mechanical Co., Ltd.), to obtain pellets.

Eta L was measured by the LAOS method in the same manner as in example 1 using the pellets obtained above^1256％/ηL^10％As a result, it was 0.463, and formula (1) was satisfied. In addition, I5 was measured^2506％/I1^2506％As a result, 0.0284 was obtained, and formula (2) was satisfied. The results are shown in table 2.

Using the pellets thus obtained, an extrusion-laminated sample was produced in the same manner as in example 1, and the thickness of the laminated layer of the ethylene-based polymer having a width of 200mm at the center in the width direction was measured. The standard deviation of the obtained measurement values was 0.53.

< comparative example 1>

An impregnated powder was produced in the same manner as in example 1. The impregnated powder obtained above was added to 100 parts by mass of a vinyl polymer (SUMIKA THENE CE4506, manufactured by Sumitomo chemical Co., Ltd.) so that the concentration thereof became 5800ppm, and kneaded in advance, and then melt-kneaded at 240 ℃ using a melt-kneading extruder (c) (manufactured by Takeda Plastic machinery Co., Ltd.) having a screw diameter of 40mm, to obtain pellets.

Eta L was measured by the LAOS method in the same manner as in example 1 using the pellets obtained above^1256％/ηL^10％As a result, it was 0.438, and formula (1) was satisfied. On the other hand, I5 was measured^2506％/I1^2506％As a result, 0.0329 was obtained, and formula (2) was not satisfied. The results are shown in table 2.

Using the pellets thus obtained, an extrusion-laminated sample was produced in the same manner as in example 1, and the thickness of the ethylene-based polymer layer having a width of 200mm at the center in the width direction was measured. The standard deviation of the obtained measurement values was 1.05, and thickness unevenness occurred.

< comparative example 2>

eta.L was measured by the LAOS method in the same manner as in example 1 using pellets of an ethylene polymer (SUMIKA THENE L420, manufactured by Sumitomo chemical Co., Ltd.)^1256％/ηL^10％As a result, it was 0.361, and formula (1) was not satisfied. In addition, I5 was measured^2506％/I1^2506％As a result, 0.0329 was obtained, and formula (2) was not satisfied. The results are shown in table 2.

Using the pellets thus obtained, an extrusion-laminated sample was produced in the same manner as in example 1, and the thickness of the ethylene-based polymer layer having a width of 200mm at the center in the width direction was measured. The standard deviation of the obtained measurement values was 1.45, and thickness unevenness occurred.

TABLE 2