JP2003268169A - Films and stretch film for packaging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide films which excel in resistance to whitening and are suitable as stretch films for packaging, and to provide a stretch film for packaging which excels in resistance to whitening. <P>SOLUTION: The films have a layer comprising an olefin polymer which meets X of formula (2): X≥0.02 to be defined by formula (1): X=[A(T2M)-A(T 2C)]/[|(T2A-T2B)|] [wherein A(T2M), A(T2C), T2A, and T2B are values to be obtained from the results of the pulse NMR which measured the olefin polymer, a specified propylene polymer, and their testing compositions, and the A(T2M) is a calculated value with a curve based on a measured T2 relaxation time, and the A(T2C) is a calculated value with a curve based on a calculated T2 relaxation time], and the stretch film for packaging is composed of the above films. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to films suitable as a stretch film for packaging and a stretch film for packaging. The film and the sheet are distinguished by the thickness, but in the present invention, the film and the sheet are collectively referred to as films.

[0002]

2. Description of the Related Art Conventionally, a vinyl chloride resin is mainly used in a stretch film for packaging in which foods such as fruits and vegetables, fresh fish, fresh meat, and prepared foods are put directly or on a plastic tray and stretch-wrapped with a film. ing. In recent years, from the viewpoint of safety and hygiene, development of polyethylene resins such as low density polyethylene and ethylene-vinyl acetate copolymer has been actively conducted in place of conventional vinyl chloride resins.

JP-A-2000-52510 discloses an amorphous olefin-based polymer and a crystalline olefin-based resin obtained by using an ethylene-vinyl acetate copolymer for both surface layers and a specific metallocene catalyst. A stretch film for packaging, which is composed of a laminate of two kinds and three layers using the composition, is disclosed as an alternative to the stretch film for packaging made of vinyl chloride resin.

[0004]

The laminate described in the publication realizes various excellent properties of a stretch film for packaging made of a vinyl chloride resin, but has a problem that it tends to whiten with the passage of time. was there. An object of the present invention is to provide films that are excellent in whitening resistance and are suitable as a stretch film for packaging, and a stretch film for packaging that is excellent in whitening resistance.

[0005]

The present invention relates to films having a layer containing the following olefin polymer, and a packaging stretch film comprising the films. Olefin polymer: X defined by formula (1)
Is an olefin polymer satisfying the condition of formula (2). X = [A (T2M) -A (T2C)] / [| (T2A-T2B) |] Formula (1) X ≧ 0.02 Formula (2) A (T2M), A (T2C) in Formula (1) above ), T
2A and T2B are the olefin polymer, one propylene polymer selected from the group consisting of the following (A) and (B), and a test composition comprising the olefin polymer and the propylene polymer. A value obtained by using the measured result of the measured pulse NMR,
(T2M) and A (T2C) are T2 of the test composition.
It is a value obtained by definite integration of a curve obtained by plotting the relaxation time on the vertical axis and the weight fraction Pa of the olefin polymer in the test composition on the horizontal axis in the range Pa = 0 to 1. . However, A (T2M) is the T2 relaxation time of the test composition of each composition obtained by pulse NMR measurement for a plurality of test compositions having different weight fractions Pa (that is, measured T2 relaxation time: T2M ( Pa)) and plot 3
It is a value calculated for a curve based on the multiple regression equation obtained by the secondary regression, and A (T2C) is the T2 relaxation time obtained by pulsed NMR measurement for the propylene polymer, and for T2A and the olefin polymer. T2B, which is the T2 relaxation time obtained by pulsed NMR measurement
Is used to plot the T2 relaxation time (that is, the calculated T2 relaxation time: T2C (Pa)) obtained by the equation (3),
It is a value calculated for a curve based on the multiple regression equation obtained by the cubic regression. Here, PvA (Pa) is a value calculated by the equation (4). VA and VC (Pa) contained in the formula (4) were observed in the range of 70 to 150 μs of free induction decay obtained by pulsed NMR measurement of the propylene polymer and the test composition of each composition. It is the volume fraction of the component. (A) The melt flow rate at 230 ° C. under a load of 2.16 kg is 12.0 ± 3.0 g / 10 minutes, and JI
The main peak temperature (melting point) based on melting of crystals obtained by measurement with a differential scanning calorimeter according to SK 7121 is 1
The temperature is 60 ± 3 ° C., and the heat of fusion of the crystal obtained by measurement with a differential scanning calorimeter according to JIS K 7122 is 10
The propylene homopolymer (B) having a load of 0 ± 5 J / g, the melt flow rate at 230 ° C. under a load of 2.16 kg is 1.0 ± 0.6 g / 10 min, and the JIS
The main peak temperature (melting point) based on the melting of crystals obtained by measurement with a differential scanning calorimeter according to K 7121 is 13
The temperature is 5 ± 2 ° C., and the heat of fusion of the crystal obtained by measurement with a differential scanning calorimeter according to JIS K 7122 is 60 ±.
5 J / g propylene-ethylene random copolymer The present invention is described in detail below.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The olefin polymer used in the present invention is an olefin polymer in which X defined by the formula (1) satisfies the condition of the formula (2), and the whitening resistance of the obtained films is Excellent in. X = [A (T2M) -A (T2C)] / [| (T2A-T2B) |] Formula (1) X ≧ 0.02 Formula (2)

The condition of the formula (2) is preferably X ≧ 0.0.
5, more preferably X ≧ 0.1, further preferably X ≧ 0.2, and particularly preferably X ≧ 0.2.
It is 5. When the stretch whitening resistance of the obtained film is required, the condition of the formula (2) is preferably 0.4.
≧ X, more preferably 0.38 ≧ X, still more preferably 0.36 ≧ X, particularly preferably 0.34 ≧ X, and particularly preferably 0.32 ≧ X.

A (T2M), A in the above formula (1)
(T2C), T2A and T2B are the olefin polymer, one propylene polymer selected from the group consisting of the following (A) and (B), and a test consisting of the olefin polymer and the propylene polymer. It is a value obtained using the measurement results of pulsed NMR measured for the composition for use. (A) The melt flow rate at 230 ° C. under a load of 2.16 kg is 12.0 ± 3.0 g / 10 minutes, and JI
The main peak temperature (melting point) based on the melting of the crystal obtained by measuring with a differential scanning calorimeter (DSC) according to SK 7121 is 160 ± 3 ° C., and the melting of the crystal obtained by measuring with DSC according to JIS K 7122. Calorie 100
The melt flow rate at 230 ° C under a load of 2.16 kg of propylene homopolymer (B) of ± 5 J / g is 1.0 ± 0.6 g / 10 minutes, and JIS
Main peak temperature (melting point) based on melting of crystals obtained by DSC measurement according to K 7121 is 135 ± 2 ° C.
And the propylene-ethylene random copolymer in which the heat of fusion of the crystals obtained by DSC measurement according to JIS K 7122 is 60 ± 5 J / g. The sample preparation for differential scanning calorimeter (DSC) measurement is JI
It is carried out in accordance with the method described in "3. Conditioning of test piece (2) When measuring melting temperature after constant heat treatment" of SK 7121.

In the above formula (1), A (T2M) and A (T2C) are the weight fraction Pa of the olefin polymer in the test composition with the T2 relaxation time of the test composition as the vertical axis. The curve obtained by plotting on the horizontal axis is Pa = 0.
It is a value obtained by definite integration in the range of ˜1. However, A
(T2M) is T2 relaxation time of the test composition of each composition obtained by pulse NMR measurement for a plurality of test compositions having different weight fractions Pa (that is, measured T2 relaxation time: T2M (Pa)). Is a value calculated for a curve based on a multiple regression equation obtained by plotting the above, and A (T2C) is a T2 relaxation time T2 obtained by pulsed NMR measurement of the propylene polymer.
Using T2B, which is the T2 relaxation time obtained by pulsed NMR measurement of A and the olefin polymer,
T2 relaxation time obtained by the equation (3) (that is, calculated T2
Relaxation time: T2C (Pa)) is plotted, and is a value calculated for a curve based on a multiple regression equation obtained by cubic regression. In addition, in each of the third-order regression, T2A and T2B
(That is, when Pa = 0 and when Pa = 1) and the weight ratio of the olefin polymer to the propylene polymer is 2
0/80, 40/60, 60/40, 80/20 test composition (ie Pa = 0.2, 0.4, 0.6,
(When 0.8) T2M (Pa) or T2C (Pa)
Shall be plotted.

The T2 relaxation time obtained by pulsed NMR measurement is called spin-spin relaxation time (or transverse relaxation time). Free Induction Decay (FID) that typically occurs after a single 90 ° pulse
Since the action decay decays according to exp (-t / T2), the T2 relaxation time T2
Can be asked. The actual measurement of the spin-spin relaxation time by pulsed NMR is described in, for example, J. Chem. Phys. 82, 4327 (1985).

X in the present invention is a parameter for evaluating the degree of mutual penetration of the propylene polymer and the olefin polymer contained in the test composition, and the T2 relaxation time used for calculating X is FID 70 ~ 15
The value obtained from the range of 0 μs shall be adopted.
That is, of the FID data obtained by measurement, 70-
The decay time t in the range of 150 μs and the macroscopic magnetization M (t) value are extracted, and the relational expression is linearly approximated by the least squares method with t as the horizontal axis and the natural logarithmic value of M (t) as the vertical axis. The T2 relaxation time is the reciprocal of the absolute value of the slope of the obtained straight line.

PvA (Pa) included in the above equation (3)
Is 70 to 150 μm of the FID obtained by pulsed NMR measurement of the test composition at each composition ratio Pa.
It is the volume fraction of the component based on the propylene polymer in the component observed in the range of seconds, and is calculated by the following formula (4). Here, VA and VC (Pa) are FID 70 to 1 obtained by pulse NMR measurement for the propylene polymer and the test composition of each composition, respectively.
It is the volume fraction of the component observed in the range of 50 μsec. Note that VC (Pa) when Pa = 0 is a value for the propylene polymer, and VC (0) = VA.

The volume fraction of the component observed in the range of 70 to 150 μsec of FID is 0 to 70 μsec of FID, 7
It is calculated from each volume fraction of 0 to 150 μsec and 150 μsec. More specifically, from the FID data,
Maximum macroscopic magnetization M included in the range of 0 to 70 μs
(T) or M (t) max, 70 μs M (t) or M (70), and 150 μs M (t) or M (1
50) Extract each, [M (70) -M (150)]
/ M (t) max is calculated.

In the present invention, FID of 70 to 150 derived from the propylene polymer present in the test composition is used.
It is assumed that the component volume fractions of the components observed in the microsecond range decrease linearly as the propylene polymer component decreases. The molecule on the right side of the above formula (4) represents it, and by dividing the molecule by VC (Pa) in each composition, the formula (4) gives the FID of each test composition of each composition. FI derived from propylene polymer in all components observed in the range of 70 to 150 μsec
The volume fraction PvA (Pa) of the component observed in the range of 70 to 150 μs of D is calculated.

Then, in the denominator on the right side of the above formula (3), the volume fraction PvA (Pa) occupied by the propylene polymer-derived component.
T2 relaxation time T obtained for the propylene polymer
The value obtained by dividing the volume fraction [1-PvA (Pa)] occupied by the olefin polymer-derived component by the T2 relaxation time T2B obtained for the olefin polymer is calculated, By obtaining the reciprocal number on the right side of the above formula (3), it was assumed that the propylene polymer and the olefin polymer accounted for the highest interpenetration in the components observed in the FID range of 70 to 150 μsec. T2C, which is the calculated T2 relaxation time of the composition in the case (composition ratio is Pa)
(Pa) is obtained by the above equation (3).

X obtained by the above equation (1) is a value for evaluating the difference between the actually measured T2 relaxation time and the calculated T2 relaxation time. The smaller this value is, the closer the actual measurement is to the calculation, and the propylene The degree of mutual penetration between the polymer and the olefin polymer is high, and conversely, the larger this value is, the farther the actual measurement and the calculation are from each other, and the lower the degree of mutual penetration between the propylene polymer and the olefin polymer is. Become.

The olefin polymer used in the present invention is
Its intrinsic viscosity [η] is preferably 0.3 to 10.0 dl
/ G, more preferably 0.5 to 7.0 dl / g, still more preferably 0.7 to 5.0 dl / g. If the intrinsic viscosity is too low, the resulting stretch film for packaging may have poor whitening resistance (bleeding whitening resistance). If the intrinsic viscosity is too high, the flexibility of the resulting stretch film for packaging may be poor.

The intrinsic viscosity [η] is measured in a tetralin at 135 ° C. using an Ubbelohde viscometer. The sample is 300 mg dissolved in 100 ml tetralin and 3 mg /
Prepare ml solution. Furthermore, the solution is 1/2, 1 /
Dilute it to 3, 1/5 and put it at 135 ℃ (± 0.1
(° C) in a constant temperature oil bath. The measurement is repeated three times at each concentration, and the obtained values are averaged and used.

The olefin polymer used in the present invention is
The molecular weight distribution (Mw / Mn) is preferably 5 or less, more preferably 4 or less, and further preferably 3 or less. If the molecular weight distribution is too wide, the flexibility and whitening resistance (bleeding whitening resistance) of the resulting stretch film for packaging may be poor.

The molecular weight distribution is determined by gel permeation chromatography (GPC) method (for example, 150C / GPC apparatus manufactured by Waters). Elution temperature is 1
40 ° C, the column used is, for example, Sode manufactured by Showa Denko KK
x Packed Column A-80M, polystyrene is used as a molecular weight standard substance. The ratio (Mw / Mn) of the obtained polystyrene reduced weight average molecular weight (Mw) and the number average molecular weight (Mn) is defined as the molecular weight distribution. As a measurement sample, about 5 mg of a polymer is dissolved in 5 ml of o-dichlorobenzene to have a concentration of about 1 mg / ml. 400 μl of the obtained sample solution is injected, the elution solvent flow rate is set to 1.0 ml / min, and the sample is detected by a refractive index detector.

The olefin polymer used in the present invention is
Using a differential scanning calorimeter (DSC), JIS K 712
1 J / g based on the melting of crystals when measured according to 2.
It is preferable to have neither of the above peaks nor peaks of 1 J / g or more due to crystallization. When it has such a peak, when the obtained packaging stretch film is used to wrap a food tray, the stretched portion of the film may be whitened. As the differential scanning calorimeter, for example, DSC220C manufactured by Seiko Denshi Kogyo Co., Ltd. is used, and measurement is performed at a rate of 10 ° C./min in both the temperature rising and temperature lowering processes.

The olefin polymer used in the present invention is
It is preferable that the olefin polymer has a strength at tensile breaking of less than 2 MPa measured according to JIS K6251. The tensile breaking strength is more preferably 1.6.
It is less than MPa, more preferably less than 1.2 MPa, particularly preferably less than 0.8 MPa. If it is out of this range, the flexibility of the resulting stretch film for packaging may be poor.

A preferred embodiment of the olefin polymer used in the present invention is ethylene, α-C 3-20.
It is a polymer obtained by homopolymerizing or copolymerizing monomers selected from olefins, polyene compounds, cyclic olefins and vinyl aromatic compounds. The olefin polymer used in the present invention is preferably a random copolymer obtained by the above-mentioned copolymerization from the viewpoint of flexibility of the obtained films. Specific examples of such a monomer include the following monomers (a) to (d).

(A) α-Olefin The above-mentioned α-olefin includes linear and branched α-olefins.
-Olefin can be used arbitrarily, and is not particularly limited, but for example, propylene, 1-butene, 1-pentene, 1-
Hexene, 1-heptene, 1-octene, 1-nonene,
1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1
-Nanodecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene, 2,2,4-trimethyl-1-pentene And the like, preferably linear α-olefins, more preferably propylene, 1
-Butene, 1-pentene, 1-hexene, 1-octene or 1-decene.

(B) Polyene Compound In the polyene compound, one single bond is formed between double bonds.
A so-called conjugated polyene compound sandwiched therebetween and other non-conjugated polyene compounds are included. Examples of the conjugated polyene compound include an aliphatic conjugated polyene compound and an alicyclic conjugated polyene compound. The aliphatic conjugated polyene compound includes a linear aliphatic conjugated polyene compound and a branched aliphatic conjugated polyene compound. Further, the aliphatic conjugated polyene compound and the alicyclic conjugated polyene compound may contain an alkoxy group, an aryl group, an aryloxy group, an aralkyl group, an aralkyloxy group and the like. As the aliphatic conjugated polyene compound, for example,
1,3-butadiene, isoprene, 2-ethyl-1,3
-Butadiene, 2-propyl-1,3-butadiene, 2
-Isopropyl-1,3-butadiene, 2-hexyl-
1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-
Methyl-1,3-pentadiene, 2-methyl-1,3-
Hexadiene, 2-methyl-1,3-octadiene, 2
-Methyl-1,3-decadiene, 2,3-dimethyl-
Examples include 1,3-pentadiene, 2,3-dimethyl-1,3-hexadiene, 2,3-dimethyl-1,3-octadiene, and 2,3-dimethyl-1,3-decadiene. As the alicyclic conjugated polyene compound, for example,
2-methyl-1,3-cyclopentadiene, 2-methyl-1,3-cyclohexadiene, 2,3-dimethyl-
1,3-cyclopentadiene, 2,3-dimethyl-1,
3-cyclohexadiene, 2-chloro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 1-fluoro-1,3-butadiene, 2-chloro-1,3-pentadiene, 2-chloro Examples include -1,3-cyclopentadiene and 2-chloro-1,3-cyclohexadiene.

Examples of non-conjugated polyene compounds include aliphatic non-conjugated polyene compounds, alicyclic non-conjugated polyene compounds and aromatic non-conjugated polyene compounds. The aliphatic non-conjugated polyene compound includes a linear aliphatic non-conjugated polyene compound and a branched aliphatic non-conjugated polyene compound. Further, the aliphatic non-conjugated polyene compound, the alicyclic non-conjugated polyene compound and the aromatic non-conjugated polyene compound include an alkoxy group, an aryl group, an aryloxy group,
It may contain an aralkyl group, an aralkyloxy group or the like. As the aliphatic non-conjugated polyene compound, for example,
1,4-hexadiene, 1,5-hexadiene, 1,6
-Heptadiene, 1,6-octadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene,
1,13-tetradecadiene, 1,5,9-decatriene, 3-methyl-1,4-hexadiene, 4-methyl-
1,4-hexadiene, 5-methyl-1,4-hexadiene, 4-ethyl-1,4-hexadiene, 3-methyl-1,5-hexadiene, 3.3-dimethyl-1,4-
Hexadiene, 3,4-dimethyl-1,5-hexadiene, 5-methyl-1,4-heptadiene, 5-ethyl-
1,4-heptadiene, 5-methyl-1,5-heptadiene, 6-methyl-1,5-heptadiene, 5-ethyl-1,5-heptadiene, 3-methyl-1,6-heptadiene, 4-methyl- 1,6-heptadiene, 4,4-
Dimethyl-1,6-heptadiene, 4-ethyl-1,6
-Heptadiene, 4-methyl-1,4-octadiene,
5-methyl-1,4-octadiene, 4-ethyl-1,
4-octadiene, 5-ethyl-1,4-octadiene, 5-methyl-1,5-octadiene, 6-methyl-
1,5-octadiene, 5-ethyl-1,5-octadiene, 6-ethyl-1,5-octadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene, 6-ethyl- 1,6-octadiene, 6-propyl-1,6-octadiene, 6-butyl-1.6-octadiene, 4-methyl-1,4-nonadiene, 5-methyl-1,4-nonadiene, 4-ethyl- 1,4-nonadiene, 5-ethyl-1,4-nonadiene, 5-methyl-1,5-nonadiene, 6-methyl-1,5-nonadiene, 5-ethyl-1,5-nonadiene, 6-ethyl-
1,5-nonadiene, 6-methyl-1,6-nonadiene, 7-methyl-1,6-nonadiene, 6-ethyl-
1,6-nonadiene, 7-ethyl-1,6-nonadiene, 7-methyl-1,7-nonadiene, 8-methyl-
1,7-nonadiene, 7-ethyl-1,7-nonadiene, 5-methyl-1,4-decadiene, 5-ethyl-
1,4-decadiene, 5-methyl-1,5-decadiene, 6-methyl-1,5-decadiene, 5-ethyl-
1,5-decadiene, 6-ethyl-1,5-decadiene, 6-methyl-1,6-decadiene, 6-ethyl-
1,6-decadiene, 7-methyl-1,6-decadiene, 7-ethyl-1,6-decadiene, 7-methyl-
1,7-decadiene, 8-methyl-1,7-decadiene, 7-ethyl-1,7-decadiene, 8-ethyl-
1,7-decadiene, 8-methyl-1,8-decadiene, 9-methyl-1,8-decadiene, 8-ethyl-
1,8-decadiene, 6-methyl-1,6-undecadiene, 9-methyl-1,8-undecadiene, 6,10
-Dimethyl 1,5,9-undecatriene, 5,9-dimethyl-1,4,8-decatriene, 4-ethylidene 8
-Methyl-1,7-nonadiene, 13-ethyl-9-methyl-1,9,12-pentadecatriene, 5,9,1
3-trimethyl-1,4,8,12-tetradecadiene, 8,14,16-trimethyl-1,7,14-hexadecatriene, 4-ethylidene-12-methyl-1,
11-Pentadecadiene and the like are exemplified.

Examples of the alicyclic non-conjugated polyene compound include vinyl cyclohexene, 5-vinyl 2-norbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropenyl-2-norbornene, Cyclohexadiene, dicyclopentadiene, cyclooctadiene, 2,5-norbornadiene,
2-methyl-2,5-norbornadiene, 2-ethyl-
2,5-norbornadiene, 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 6-chloromethyl-5-
Isopropenyl-2-norbornene, 1,4-divinylcyclohexane, 1,3-divinylcyclohexane,
1,3-divinylcyclopentane, 1,5-divinylcyclooctane, 1-allyl-4-vinylcyclohexane, 1,4-diallylcyclohexane, 1-allyl-5
-Vinylcyclooctane, 1,5-diallylcyclooctane, 1-allyl-4-isopropenylcyclohexane, 1-isopropenyl-4-vinylcyclohexane,
Examples thereof include 1-isopropenyl-3-vinylcyclopentane and methyltetrahydroindene. Examples of the aromatic non-conjugated polyene compound include divinylbenzene, vinylisopropenylbenzene and the like.

(C) Cyclic olefin Examples of the cyclic olefin include norbornene, 5-methylnorbornene, 5-ethylnorbornene, 5-propylnorbornene, 5,6-dimethylnorbornene, 1-methylnorbornene, 7-methylnorbornene, 5,5,6-trimethylnorbornene, 5-phenylnorbornene, 5-benzylnorbornene, 5-
Ethylidene norbornene, 5-vinyl norbornene,
1,4,5,8-dimethano-1,2,3,4,4a,
5,8,8a-octahydronaphthalene, 2-methyl-
1,4,5,8-dimethano-1,2,3,4,4a,
5,8,8a-octahydronaphthalene, 2-ethyl-
1,4,5,8-dimethano-1,2,3,4,4a,
5,8,8a-octahydronaphthalene, 2,3-dimethyl-1,4,5,8-dimethano-1,2,3,4,4
a, 5,8,8a-octahydronaphthalene, 2-hexyl-1,4,5,8-dimethano-1,2,3,4,4
a, 5,8,8a-octahydronaphthalene, 2-ethylidene-1,4,5,8-dimethano-1,2,3,4
4a, 5,8,8a-octahydronaphthalene, 2-fluoro-1,4,5,8-dimethano-1,2,3,4
4a, 5,8,8a-octahydronaphthalene, 1,5
-Dimethyl-1,4,5,8-dimethano-1,2,3
4,4a, 5,8,8a-octahydronaphthalene, 2
-Cyclohexyl-1,4,5,8-dimethano-1,
2,3,4,4a, 5,8,8a-octahydronaphthalene, 2,3-dichloro-1,4,5,8-dimethano-
1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-isobutyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a- Octahydronaphthalene, 1,2-dihydrodicyclopentadiene,
5-chloronorbornene, 5,5-dichloronorbornene, 5-fluoronorbornene, 5,5,6-trifluoro-6-trifluoromethylnorbornene, 5-chloromethylnorbornene, 5-methoxynorbornene,
5,6-dicarboxylic norbornene anhydrate, 5-dimethylaminonorbornene, 5-cyanonorbornene, cyclopentene, 3-methylcyclopentene, 4-methylcyclopentene, 3,4-dimethylcyclopentene, 3,5-dimethylcyclopentene, 3- Examples include chlorocyclopentene, cyclohexene, 3-methylcyclohexene, 4-methylcyclohexene, 3,4-dimethylcyclohexene, 3-chlorocyclohexene, cycloheptene and the like.

(D) Vinyl aromatic compound Examples of the vinyl aromatic compound include styrene and
α-methylstyrene, p-methylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, fluorostyrene,
Examples of p-tert-butylstyrene, ethylstyrene, vinylnaphthalene and the like.

From the viewpoint of achieving transparency when the films of the present invention are used as a stretch film for packaging, a copolymer composed of a combination of specific monomers selected from the above monomers is used. Preferably, examples of such a preferable copolymer include the following (A) to (D). (A) An olefin polymer obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms as an essential component, and optionally copolymerizing one or more kinds of monomers selected from polyene compounds, cyclic olefins and vinyl aromatic compounds. . (B) An olefin polymer obtained by copolymerizing ethylene and an α-olefin having 4 to 20 carbon atoms as an essential component, and optionally copolymerizing one or more kinds of monomers selected from polyene compounds, cyclic olefins and vinyl aromatic compounds. . (C) ethylene, propylene, and 4 to 2 carbon atoms
An olefin polymer obtained by copolymerizing 0 or more α-olefin as an essential component and optionally one or more kinds of monomer components selected from polyene compounds, cyclic olefins and vinyl aromatic compounds. (D) An olefin obtained by copolymerizing propylene and an α-olefin having 4 to 20 carbon atoms as an essential component and optionally one or more kinds of monomers selected from polyene compounds, cyclic olefins and vinyl aromatic compounds. Polymer.

Specific examples include the following (e) to (e). (E) An olefin polymer obtained by copolymerizing ethylene and an α-olefin having 4 to 20 carbon atoms. (F) An olefin polymer obtained by copolymerizing ethylene, an α-olefin having 4 to 20 carbon atoms, and a polyene compound. (G) An olefin polymer obtained by copolymerizing ethylene, an α-olefin having 4 to 20 carbon atoms, and a cyclic olefin compound. (H) An olefin polymer obtained by copolymerizing ethylene, an α-olefin having 4 to 20 carbon atoms and a vinyl aromatic compound. (I) An olefin polymer obtained by copolymerizing ethylene, an α-olefin having 4 to 20 carbon atoms, a polyene compound and a vinyl aromatic compound. (Nu) ethylene, propylene, and 4 to 2 carbon atoms
An olefin polymer obtained by copolymerizing 0 α-olefin. (L) ethylene, propylene, α having 4 to 20 carbon atoms
An olefin polymer obtained by copolymerizing an olefin and a polyene compound. (E) ethylene, propylene, α having 4 to 20 carbon atoms
An olefin polymer obtained by copolymerizing an olefin and a cyclic olefin compound. (W) ethylene, propylene, α having 4 to 20 carbon atoms
An olefin polymer obtained by copolymerizing an olefin and a vinyl aromatic compound. (F) Ethylene, propylene, α having 4 to 20 carbon atoms
An olefin polymer obtained by copolymerizing an olefin, a polyene compound and a vinyl aromatic compound. (Y) An olefin polymer obtained by copolymerizing propylene and an α-olefin having 4 to 20 carbon atoms. (T) An olefin polymer obtained by copolymerizing propylene, an α-olefin having 4 to 20 carbon atoms, and a polyene compound. (L) An olefin polymer obtained by copolymerizing propylene, an α-olefin having 4 to 20 carbon atoms and a cyclic olefin compound. (So) An olefin polymer obtained by copolymerizing propylene, an α-olefin having 4 to 20 carbon atoms, and a vinyl aromatic compound. (T) An olefin polymer obtained by copolymerizing propylene, an α-olefin having 4 to 20 carbon atoms, a polyene compound and a vinyl aromatic compound.

Of these, when cold resistance of the obtained stretch film for packaging is required, the olefin polymer (b) or (c) is preferably used, and the olefin polymer (d) is most preferable. It is preferably used.

The olefin polymer used in the present invention is
Examples of the polymerization catalyst include (α) dimethylsilyl (tetramethylcyclopentadienyl) (3-tert-butyl-5-methyl-2-phenoxy) titanium dichloride, (β) triisobutylaluminum and (γ) triphenylmethyl. Using a catalyst obtained by contacting tetrakis (pentafluorophenyl) borate with, for example, ethylene, propylene, and 4 to 20 carbon atoms.
In the case of an olefin polymer obtained by copolymerizing the α-olefin of the above, it may be produced within the range of the following conditions so that the molar content (Emol%) of the repeating unit derived from ethylene falls within the range below. it can. [50- (0.5
× Pmol%)] ≦ Emol% ≦ 80 where Pmol%
Is the molar content of repeating units derived from propylene in the olefin polymer, ethylene, propylene,
And the total molar content of repeating units derived from α-olefin having 4 to 20 carbon atoms is 100.

Regarding the amount of components (α) to (γ) used, the ratio of component (β) / component (α) is usually 0.1 to 1 in terms of molar ratio.
0000, preferably 5 to 2000, and the component (γ)
The molar ratio of component / component (α) is usually 0.01 to 100,
It is preferably 0.5 to 10. When the components (α) to (γ) are used as a solution or a suspension, the concentration may be appropriately selected depending on the conditions such as the performance of the device that supplies each component to the polymerization reactor. The concentration of component (α) is usually 0.0
1 to 500 μmol / g, preferably 0.05 to 100
μmol / g, more preferably 0.05 to 50 μmo
1 / g. The concentration of the component (β) is usually 0.01 to 10000 μmol / g in terms of Al atom, preferably,
0.1-5000 μmol / g, more preferably 0.1.
It is 1 to 2000 μmol / g. The concentration of the component (γ) is usually 0.01 to 500 μmol / g, preferably
0.05-200 μmol / g, more preferably 0.
It is 05-100 micromol / g.

The polymerization method of the olefin polymer is not limited. Examples of the polymerization method include a solvent polymerization method using a solvent and a slurry polymerization method, and a gas phase polymerization method not using a solvent. Examples of the solvent include aliphatic hydrocarbons such as butane, pentane, hexane, heptane and octane; aromatic hydrocarbons such as benzene and toluene; and halogenated hydrocarbons such as methylene dichloride. The polymerization can be either continuous polymerization or batch polymerization. Polymerization temperature is usually -5
It is 0 to 200 ° C., particularly preferably −20 to 100 ° C. The polymerization pressure is preferably atmospheric pressure to 60 kg / cm ² G. The polymerization time is appropriately determined depending on the type of catalyst used and the reaction device, and is generally 1 minute to 20 hours. Chain transfer agents such as hydrogen may be used to control the molecular weight of the resulting olefin polymer.

The layer containing the olefin polymer contained in the films of the present invention may consist of the olefin polymer alone as a resin component, or may be a thermoplastic resin other than the olefin polymer and the olefin polymer. It may be composed of a thermoplastic resin composition consisting of, and is preferably composed of the latter thermoplastic resin composition.

Such a thermoplastic resin composition is preferably
(I) Thermoplastic resins 1 to 9 other than the above olefin polymers
A thermoplastic resin composition comprising 9% by weight and (ii) 99 to 1% by weight of the olefin polymer, and more preferably (i) 10 to 90% by weight and (ii) a thermoplastic resin composition.
A thermoplastic resin composition comprising 90 to 10% by weight of the olefin polymer, more preferably (i) 20 to 80% by weight of the thermoplastic resin and (ii) thermoplastic resin comprising 80 to 20% by weight of the olefin polymer. The resin composition is preferably a thermoplastic resin composition composed of (i) 30 to 70% by weight of a thermoplastic resin and (ii) 70 to 30% by weight of the above olefin polymer, and particularly preferably (i) a thermoplastic resin composition. A thermoplastic resin composition comprising 40 to 60% by weight of a plastic resin and (ii) 60 to 40% by weight of the olefin polymer. In addition, the notation of weight% here is notation in which the total of the component (i) and the component (ii) is 100% by weight.

The thermoplastic resin (i) is a thermoplastic resin other than the above-mentioned olefin polymer and can be widely selected from various known thermoplastic resins. For example, high density polyethylene, medium density polyethylene, low density polyethylene Polyethylene, linear low density polyethylene (LLDPE) and other polyethylene resins, polypropylene resins, polybutene resins, poly-4-methyl-1-pentene resins, polystyrene resins, polyester resins, polyamide resins, polyphenylene Examples thereof include ether resins, polyphenylene oxide resins, polyacetal resins, polycarbonate resins and the like. Preferred are polyolefin resins such as polyethylene resins and polypropylene resins. A polyolefin resin obtained by polymerizing an aliphatic olefin having 3 or more carbon atoms as a main monomer is more preferable, and a polypropylene resin is particularly preferable. These resin components may be used alone or in admixture of two or more.

The polypropylene resin is a crystalline propylene polymer mainly having an isotactic or syndiotactic sequence structure, and is widely used such as a homo type, a random type obtained by copolymerizing a comonomer, a block type by multi-stage polymerization. Various structures can be used. The polypropylene-based resin is produced by a gas phase polymerization method, a bulk polymerization method, a solvent polymerization method and a multi-stage polymerization method in which they are arbitrarily combined. The number average molecular weight of the polymer is not particularly limited, but those having a number average molecular weight of 10,000 to 1,000,000 are preferably used.

As an index of crystallinity of the polypropylene resin, for example, melting point, heat of crystal fusion, etc. are used.
Melting point is 80 ° C to 176 ° C, heat of crystal fusion is 30 J / g to
It is preferably in the range of 120 J / g. Moreover,
Melting point is 120 ° C to 176 ° C, heat of crystal fusion is 60 J / g
It is preferably in the range of 120 J / g. If the melting point of the crystal is too low or the heat of fusion is too low, the heat resistance of the obtained stretch film for packaging may be lowered.

As a method for producing a polypropylene-based resin, generally, a Ziegler / a mixture of a so-called titanium-containing solid transition metal component and an organometallic component is used.
A Natta-type catalyst or Group 4 of the periodic table having at least one group having a cyclopentadienin type anion skeleton
Using a metallocene catalyst consisting of a Group 6 transition metal compound and an activating co-catalyst component, propylene can be produced in a single stage or in a multi-stage by a polymerization method such as slurry polymerization, gas phase polymerization, bulk polymerization, solution polymerization or the like. A homopolymer is obtained by homopolymerization, or a copolymer is obtained by copolymerizing propylene and one or more olefins selected from other olefins having 2 to 12 carbon atoms in one or more stages. I can give you a way. Note that it is also possible to use a commercially available product.

When the films of the present invention are required to have excellent transparency, the polypropylene resin has a main chain of 10
It is preferable that the polypropylene-based resin has 15 or more and 205 or less methylene carbons forming two or more chains in 00 carbon chains. More preferably,
The number of methylene carbons forming two or more chains in the carbon chain of 1000 main chains is 25 or more and 155 or less, and more preferably 35 or more and 105 or less. As described above, in order to contain a predetermined amount of methylene carbons forming two or more chains, a method of copolymerizing ethylene with propylene and a method of generating a tail-tail bond of propylene can be mentioned. The content of methylene carbon forming two or more chains contained in the carbon chain of 1000 main chains can be measured by using ¹³ C-NMR or IR. ¹³ C-NMR and IR analysis methods are described, for example, in New Edition Polymer Handbook I. 2.
3 (1995).

When the films of the present invention are required to have excellent performances in impact resistance at low temperature, the polypropylene resin is a polypropylene resin obtained by copolymerizing ethylene and propylene in two or more stages. It is preferably a resin. More preferably, in the first step, the content of the repeating unit derived from propylene homopolymer or ethylene is 5.0% by weight or less-
An ethylene copolymer is obtained, and the content of repeating units derived from ethylene is 7 to 85% by weight after the second step.
The polypropylene resin in which the propylene-ethylene copolymer is obtained and the weight ratio of the polymer obtained in the first step to the polymer obtained in the second step and thereafter is 30/70 to 90/10 is used. (Hereinafter, the polymer obtained by the first-stage polymerization may be referred to as “polymer-1”. The polymer obtained by the second-stage or subsequent copolymerization may be referred to as “polymer-2”. There is.)

The content of repeating units derived from ethylene in polymer-1 is preferably 0% by weight (that is, when ethylene is not copolymerized) or 5.0% by weight or less. When the content of repeating units derived from ethylene is high, the heat resistance of the obtained films may be poor.

The content of repeating units derived from ethylene in polymer-2 is preferably 7 to 85% by weight. If the content is too small, the impact resistance at low temperature of the obtained films may be decreased, while if the content is too large, the transparency of the obtained films may be decreased. .

The weight ratio of polymer-1 and polymer-2 is polymer-1 / polymer-2 = 30/70 to 90/10. When the amount of polymer-1 is too small (the amount of polymer-2 is too large), the resulting films may not be able to obtain sufficient heat resistance, while the amount of polymer-1 is too large (the amount of polymer-2 is too small). When it is), impact resistance at low temperature of the obtained films may not be sufficient.

Polymer-1 and polymer-2 are α-olefins other than propylene and ethylene (for example,
One or more of 1-butene, 1-hexene, 1-octene, etc.) may be copolymerized in a small amount, for example, about 1 to 5% by weight.

The polypropylene-based resin composed of the polymer-1 and the polymer-2 may be commonly referred to as "block polypropylene" or "high impact polypropylene", and commercially available products can be used. .

As the resin component constituting the films of the present invention, in addition to the above components, for example, recycled resin generated from trimming loss or the like, and cuttability in automatic packaging are improved within the range not hindering the present invention. Other resins may be blended and used for the purpose of Specific examples of the other resin include rosin resins, polyterpene resins, synthetic petroleum resins, chroman resins, phenol resins, xylene resins, styrene resins, isoprene resins and cyclic olefin resins. At least one selected is included.

Examples of the rosin-based resin include natural rosin, polymerized rosin, partially and completely hydrogenated rosin, esterified products of these rosins such as glycerin ester, pentaerythritol ester, ethylene glycol ester and methyl ester, and further disproportionation. , Fumarization, liming, or a rosin derivative in which these are appropriately combined. Examples of the polyterpene resin include α-pinene, β-pinene, homopolymers or copolymers of cyclic terpenes such as dipentene, and copolymers of the above various terpenes with phenol and phenol compounds such as bisphenol. Examples thereof include terpene-phenolic resins such as -pinene-phenolic resin, dipentene-phenolic resin, terpene-bisphenolic resin, and aromatic modified terpene resins which are copolymers of the above-mentioned various terpenes and aromatic monomers. Synthetic petroleum resins include homopolymers or copolymers of C ₅ fraction, C _{6 to} C ₁₁ fraction of naphtha cracked oil and other olefinic fractions and aliphatic petroleum which is a hydrogenated product of these polymers. Examples thereof include resins, aromatic petroleum resins, alicyclic petroleum resins, and aliphatic-alicyclic copolymer resins.

Further, the above various naphtha cracked oils and the above
Copolymers with various terpenes and their hydrogenated products
Other examples include petroleum resin. Here, C of naphtha cracked oil
_FiveAs the fraction, isoprene, cyclopentadiene,
1,3-pentadiene, 2-methyl-1-butene, 2-
Methylbutenes such as methyl-2-butene, 1-pente
And pentenes such as 2-pentene, dicyclopentadiene
En is preferable, and C ₆~ C₁₁The fraction is
Amine, styrene, o-, m-, p-vinyltoluene, α
-, Methyl styrenes such as β-methylstyrene, methyl
Ruindene, ethylindene, vinylxylene, propene
Nylbenzene and the like are preferable, and other olefinic fractions
Butene, hexene, heptene, octene, pig
Diene and octadiene are preferred.

Examples of the phenol resin include alkylphenol resins, alkylphenol-acetylene resins obtained by condensation of alkylphenol and acetylene, and modified products thereof. Here, the phenolic resin may be either a novolac type resin in which phenol is converted to a methylol with an acid catalyst or a resol type resin in which a phenol is converted to a methylol with an alkali catalyst.

Examples of the xylene-based resin include a xylene-formaldehyde resin composed of m-xylene and formaldehyde, and a modified resin obtained by adding and reacting a third component with the xylene-formaldehyde resin.

Examples of the styrene resin include a low molecular weight product of polystyrene, a copolymer resin of α-methylstyrene and vinyltoluene, and a copolymer resin of styrene, acrylonitrile and indene. Examples of the isoprene-based resin include resins obtained by copolymerizing a C ₁₀ alicyclic compound which is a dimer of isoprene and a C ₁₀ chain compound.

The cyclic olefin resin is a cyclic olefin homopolymer resin or cyclic olefin copolymer resin synthesized by a known technique using a Ziegler-Natta type catalyst or a metallocene catalyst. Examples of the cyclic olefin include norbornene, 5-methylnorbornene, 5-ethylnorbornene, 5-propylnorbornene, 5,6-dimethylnorbornene, 1-methylnorbornene, 7-methylnorbornene, 5,5,6-trimethylnorbornene, 5-phenyl norbornene, 5
-Benzyl norbornene, 5-ethylidene norbornene, 5-vinyl norbornene, 1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-methyl-1, 4,5,8-Dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-ethyl-1,4,5,8-dimethano-
1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2,3-dimethyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8, 8a-octahydronaphthalene, 2-hexyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-ethylidene-1,4,5,5 8-Dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-fluoro-1,4,5,8-dimethano-1,2,3,4,4a, 5 8,8a-octahydronaphthalene, 1,5-dimethyl-1,4,5,8-
Dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-cyclohexyl-1,4
5,8-Dimethano-1,2,3,4,4a, 5,8,8
a-octahydronaphthalene, 2,3-dichloro-1,
4,5,8-Dimethano-1,2,3,4,4a, 5
8,8a-octahydronaphthalene, 2-isobutyl-
1,4,5,8-dimethano-1,2,3,4,4a,
5,8,8a-octahydronaphthalene, 1,2-dihydrodicyclopentadiene, 5-chloronorbornene,
5,5-dichloronorbornene, 5-fluoronorbornene, 5,5,6-trifluoro-6-trifluoromethylnorbornene, 5-chloromethylnorbornene, 5
-Methoxynorbornene, 5,6-dicarboxyl norbornene anhydrate, 5-dimethylaminonorbornene, 5-cyanonorbornene, cyclopentene, 3
-Methylcyclopentene, 4-methylcyclopentene,
3,4-dimethylcyclopentene, 3,5-dimethylcyclopentene, 3-chlorocyclopentene, cyclohexene, 3-methylcyclohexene, 4-methylcyclohexene, 3,4-dimethylcyclohexene, 3-chlorocyclohexene, cycloheptene, etc. Is exemplified.

Of the above-mentioned various resins, rosin resins, polyterpene resins, synthetic petroleum resins and the like are preferable, and among these, those having an aliphatic and / or alicyclic structure are transparent of the obtained films. It is more preferable from the viewpoint of sex. Particularly preferable as the resin having an aliphatic and / or alicyclic structure here is a partially or fully hydrogenated rosin and a derivative thereof in a rosin-based resin, and a homopolymer or copolymer of a cyclic terpene in a polyterpene-based resin, Examples of synthetic petroleum resins include aliphatic petroleum resins, alicyclic petroleum resins, aliphatic-alicyclic copolymer resins, and hydrogenated products of copolymers of naphtha cracked oil and various terpenes. These resin components may be used alone or in admixture of two or more. Appropriate commercially available products can be used as the resin component.

In the films of the present invention, various stabilizers such as an antioxidant, an antioxidant, an ozone deterioration inhibitor, an ultraviolet absorber and a light stabilizer are added as additional components within the range not hindering the present invention. It can be blended appropriately. Further, additives such as an antistatic agent, a slip agent, an internal release agent, a colorant, a dispersant, an antiblocking agent, a lubricant and an antifogging agent can be appropriately blended.

As a method for obtaining the thermoplastic resin composition, each of the components described above is mixed with an ordinary kneading machine such as a rubber mill, a Brabender mixer, a Banbury mixer, a pressure kneader, a ruder, a twin-screw extruder and the like. And knead. The kneading device may be either a closed type device or an open type device, but a closed type device capable of being replaced by an inert gas is preferable. The kneading temperature is a temperature at which all of the mixed components are melted, and is usually 160 to 250 ° C., preferably 180 to
It is set to 240 ° C. The kneading time depends on the type and amount of the components mixed and the type of the kneading device, and therefore cannot be generally discussed, but when a kneading device such as a pressure kneader or a Banbury mixer is used, it is usually , About 3 to 1
It will be about 0 minutes. Incidentally, in the kneading step, the respective constituent components may be kneaded together, or after kneading a part of the constituent components, the remaining constituent components are added and the kneading is continued to carry out multi-stage division kneading. A kneading method can also be adopted.

The film of the present invention is a film having a layer containing the above-mentioned olefin polymer as described above, and may be a single layer film consisting of only the layer or may be another layer. It may be a laminated film. As another layer of such laminated films, a layer made of a polyolefin-based thermoplastic resin is preferable. Specifically, low density polyethylene (LDPE); linear low density polyethylene (LLDPE); ultra low density polyethylene (VLDP)
E); high-density polyethylene (HDPE); ethylene-based copolymer, for example, ethylene-vinyl acetate copolymer (EV)
A), saponified products thereof (EVOH), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-glycidyl methacrylate copolymer (EGMA), ethylene-maleic anhydride. Acid copolymer (EMAH), ionomer resin; propylene homopolymer; propylene-ethylene copolymer; propylene-1-butene copolymer; propylene-ethylene-1-butene copolymer (random copolymer, block copolymer Polymers) and the like, and mixtures thereof.

As the other layer, an ethylene resin is preferable from the viewpoint of obtaining transparency, and linear low-density polyethylene (LLDPE) or ultra-low-density polyethylene (VLDP) is used.
E) or an ethylene-vinyl acetate copolymer is more preferable, and an ethylene-vinyl acetate copolymer having a content of repeating units derived from vinyl acetate of 5 to 30% by weight is most preferable. The content of vinyl acetate unit is JIS
Measure according to K6730.

The method for producing the ethylene-vinyl acetate copolymer is not particularly limited, and a known method, for example, a method of copolymerizing ethylene and vinyl acetate with a radical initiator can be mentioned.

The total thickness of the films of the present invention is not particularly limited and can be arbitrarily selected. When the films of the present invention are used as a stretch film for packaging, the thickness thereof is usually 1 to 100 μm, preferably 2 to 60 μm, more preferably 5 to 30 μm.
Is.

When the films of the present invention are laminated films, the thickness ratio of the layer containing the olefin polymer to the total thickness of the films is not particularly limited and can be arbitrarily selected. Usually, the thickness ratio of the layer containing the olefin polymer is 1 to 99%, preferably 5 to 90%, and more preferably 10 to 80% based on the total thickness of the films. When using the films of the present invention as a stretch film for packaging, the thickness ratio is 10 to the total thickness of the stretch film for packaging.
It is preferably 80%, more preferably 20 to 70%.

The method for producing the films of the present invention is not particularly limited, and it is possible to produce the film by a known method such as an inflation method, a T-die method or a calender method. In the case of laminated films, it may be formed by a method of heat-bonding after film formation, for example, by a coextrusion type inflation film molding machine or T-die film molding machine of two kinds two layers or two kinds three layers. It is possible.

The films of the present invention have excellent whitening resistance and are suitable as a stretch film for packaging. As the packaging stretch film, it is preferable that it is also excellent in transparency and heat resistance, and by appropriately selecting the preferred embodiment for obtaining the films of the present invention described above, it is possible to obtain a superior packaging stretch film for each. it can.

When the stretch film for packaging needs to have shrinkability, it is preferably stretched in at least uniaxial direction after the film formation. The stretching can be uniaxial or biaxial.
In the case of uniaxial stretching, for example, a commonly used roll stretching method is preferable. In the case of biaxial stretching, for example, a sequential stretching method in which uniaxial stretching is followed by biaxial stretching may be used, or a simultaneous biaxial stretching method such as tubular stretching is also possible.

[0067]

The present invention will be described in more detail with reference to the following examples, which are for illustration purposes only and are not intended to limit the present invention.

[1] Production of Olefin Polymer <Reference Example 1> Using a 100-liter SUS polymerization vessel equipped with a stirring blade, ethylene, propylene and 1-butene were continuously copolymerized as follows. . 57 liters of hexane and 7.13K of ethylene from the bottom of the polymerizer
g / hour, propylene was continuously supplied at a rate of 1.92 Kg / hour, and 1-butene was continuously supplied at a rate of 17.10 Kg / hour.
On the other hand, the polymerization liquid was continuously withdrawn from the upper part of the polymerization device so that the polymerization liquid in the polymerization device became 100 liters. As a catalyst, dimethylsilyl (tetramethylcyclopentadienyl) (3-tert-butyl-5-methyl-) having the following structural formula
2-phenoxy) titanium dichloride, triphenylmethyltetrakis (pentafluorophenyl) borate,
And triisobutylaluminum (hereinafter "TIBA")
Abbreviated as 0.012 g / hour and 0.81 respectively.
It was continuously fed into the polymerization vessel from the lower portion of the polymerization vessel at a rate of 8 g / hour and 1.654 g / hour. The copolymerization reaction is
The temperature was controlled at 52 ° C. by circulating cooling water in a jacket attached to the outside of the polymerization vessel. A small amount of ethanol was added to the polymerization liquid extracted from the polymerization vessel to stop the polymerization reaction, and after demonomerization and washing with water, the solvent was removed by steam in a large amount of water to take out the copolymer,
It was dried under reduced pressure at 24 ° C. By the above operation, ethylene-
Propylene-1-butene copolymerization was performed at a rate of 1.70 Kg / hour to obtain a copolymer (1).

Reference Example 2 Copolymerization of ethylene, propylene and 1-butene was continuously carried out as follows using a 100-liter SUS polymerization vessel equipped with a stirring blade. From the bottom of the polymerization vessel, 109 liters of hexane / hour, 3.82 kg of ethylene / hour, 0.70 kg of propylene /
For 1 hour, 1-butene was continuously fed at a rate of 6.23 Kg / hour. On the other hand, the polymerization liquid was continuously withdrawn from the upper part of the polymerization device so that the polymerization liquid in the polymerization device became 100 liters. Dimethylsilyl (tetramethylcyclopentadienyl) (3-tert-butyl-5-methyl- as a catalyst
2-phenoxy) titanium dichloride, triphenylmethyltetrakis (pentafluorophenyl) borate, and triisobutylaluminum were each added to 0.10%.
009 g / hr, 0.521 g / hr, and 1.65
It was continuously fed into the polymerization vessel from the lower portion of the polymerization vessel at a rate of 4 g / hour. The copolymerization reaction was controlled at 41 ° C. by circulating cooling water in a jacket attached to the outside of the polymerization vessel. A small amount of ethanol was added to the polymerization liquid extracted from the polymerization vessel to stop the polymerization reaction, and after demonomerization and washing with water, the solvent was removed by steam in a large amount of water to take out the copolymer, and the pressure was reduced at 80 ° C day and night. Dried. By the above operation, ethylene-propylene-1-butene copolymerization was carried out at a rate of 2.30 Kg / hour to give a copolymer (2).
Got

Reference Example 3 As a polymerization catalyst, (1) triisobutylaluminum, (2) N, N-dimethylanilinium tetrakis (pentafluoro) phenylborate, (3) dimethylsilyl (tetramethylcyclopentadienyl) ( 3-tert-butyl-5-methyl-2-
Phenoxy) titanium dichloride in a molar ratio of (1) :( 2) :( 3) = 633: 28: 1,
Copolymerization of ethylene, propylene and 1-butene was carried out in accordance with Example 1 of Japanese Patent No. 2913837 except that the polymerization temperature was 50 ° C. and the polymerization pressure was 8 Kg / cm ² . Table 1 shows the properties and other analysis results.

[2] Analysis of Olefin Polymer Copolymers (1) to (1) obtained in Reference Examples 1 to 3 of the above [1]
(3) Table 1 shows the results of each analysis.

[0072]

[Table 1] The analysis method is as follows.

(1) Ethylene-propylene-1-butene copolymerization composition The ethylene-propylene-1-butene copolymerization composition is Bru.
Using a device manufactured by Ker Co., Ltd. with a trade name of AC-250,
^It was calculated based on the measurement results of ¹ H NMR spectrum and ¹³ C NMR spectrum. Specifically, the composition ratio of propylene and 1-butene is calculated from the ratio of the propylene-derived methyl carbon spectrum intensity of the ¹³ CNMR spectrum and the 1-butene-derived methyl carbon spectrum intensity, and then the (methine + methylene) of the ¹ HNMR spectrum is calculated. ) The composition ratio of ethylene, propylene, and 1-butene was calculated from the ratio of the hydrogen-derived spectrum intensity and the methyl-derived hydrogen spectrum intensity.

(2) Intrinsic viscosity [η] It was carried out at 135 ° C. in tetralin using an Ubbelohde viscometer. As a sample, 300 mg was dissolved in 100 ml tetralin to prepare a 3 mg / ml solution. Further dilute the solution to 1/2, 1/3, 1/5 and
The measurement was carried out in a constant temperature oil bath at ℃ (± 0.1 ℃). The measurement was repeated three times at each concentration, and the obtained values were averaged and used.

(3) Measurement of molecular weight distribution The molecular weight distribution was determined by gel permeation chromatography (G
PC) method (Waters, 150C / GPC device)
Went by. The elution temperature is 140 ° C, and the column used is Shodex Packed Column A manufactured by Showa Denko KK
-80M, polystyrene was used as the molecular weight standard substance. The ratio (Mw / Mn) of the obtained polystyrene-converted weight average molecular weight (Mw) and number average molecular weight (Mn) is taken as the molecular weight distribution. The measurement sample was about 5 mg of polymer and 5 ml of o.
-Dissolve in dichlorobenzene to a concentration of about 1 mg / ml. 400 μl of the obtained sample solution was injected. The flow rate of the eluting solvent was 1.0 ml / min, and the refractive index detector was used for detection.

(4) Differential scanning calorimeter (DSC) measurement Differential scanning calorimeter (DSC220 manufactured by Seiko Instruments Inc.)
C) is used for both the temperature rising and temperature lowering processes at 10 ° C. /
Measurements were made at the speed of minutes.

[3] Evaluation of test composition Using a JNM-MU 25 pulse NMR apparatus manufactured by JEOL, at 30 ° C., at a measurement frequency of 25 MHz, with an observation nucleus of ¹ H, the measurement pulse sequence was a solid echo. It was measured by the method. Observation pulse width 2.0 μsec, FID
(Free induction decay) After observation, the waiting time until the next pulse was given was set to 1 second, and the number of integration was set to 64 times. The T2 relaxation time was determined from the range of FID 70 to 150 μS. Specifically, the decay time t and the macroscopic magnetization M (t) value in the range of 70 μsec to 150 μsec are extracted from the FID data obtained by the above-mentioned method (the observation pulse width is 2.0 μsec. (Data is extracted), t is the horizontal axis, and M (t)
A plot with the natural logarithmic value of as the vertical axis was drawn, the relationship was linearly approximated by the least squares method, and the reciprocal of the absolute value of the slope of the obtained straight line was taken as T2 relaxation time.

In Tables 2 and 3, the pulse NM of the test composition of the copolymer (1) obtained in Reference Example 1 and the following propylene-ethylene random copolymer PP-1 was tested.
The results of R measurement are summarized. PP-1: melting point is 135 ° C., 230 ° C., 2.16
Propylene-ethylene random copolymer resin having a MFR under a load of 0.88 (g / 10 minutes) and containing 4.9% by weight of a repeating unit derived from ethylene (Nobrene S131 manufactured by Sumitomo Chemical Co., Ltd.).

Table 2 shows the results of pulsed NMR measurement for PP-1 only, where T2M (Pa) is T2A.
Corresponds to. Similarly, T2M (Pa) in Table 3 is T2B
Corresponds to. The value of VA was obtained by the method described above from the measurement result of, and the same value was used when obtaining each PvA (Pa). The value of VC (Pa) is
~ It was obtained from the respective measurement results by the method already described.
M (t) max, M (70), and M (150) were also obtained by the methods already described.

[0080]

[Table 2]

[0081]

[Table 3] * 1: Extraction of decay time t and macroscopic magnetization M (t) value in the range of 70 μsec to 150 μsec from the free induction decay (FID) data of pulse NMR measurement (41 pieces because the observation pulse width is 2.0 μsec. Data is extracted), t is the horizontal axis, and M
A plot with the natural logarithmic value of (t) as the vertical axis is drawn, the relationship is linearly approximated by the least squares method, and the slope and intercept of the obtained straight line. * 2: Reciprocal of the absolute value of the slope obtained in * 1.

With the same calculation procedure, T2M (Pa) and T2C (Pa) were calculated for the copolymer (2) and the copolymer (3) obtained in Reference Example 2 and Reference Example 3, respectively. It is summarized in Table 4.

[Table 4] In Table 4, a, b, c, and d are Pa on the horizontal axis and T
2M (Pa) or T2C (Pa) is plotted on the vertical axis, and each coefficient (a, b, c) and intercept (d) of the multiple regression equation when the relationship is obtained as a multiple regression equation by cubic regression.
Is. Y = aX ³ + bX ² + cX + d The obtained multiple regression equation is definitely integrated in the range of Pa = 0 to 1 to obtain A
(T2M) and A (T2C) were obtained, and the value X obtained by the above equation (1) is also shown in Table 4. It was confirmed that the copolymer (1) and the copolymer (2) satisfy the above formula (2) of the present invention, but the copolymer (3) does not satisfy the formula (3).

[4] Evaluation of stretch film for packaging <Example 1> (1) Preparation of resin composition for surface layer Ethylene-vinyl acetate copolymer (Evatate H2081, manufactured by Sumitomo Chemical Co., Ltd., MFR (190 ° C)) = 2g / 1
0 minutes, 97 parts by weight of a repeating unit derived from vinyl acetate = 15.8% by weight and 3 parts by weight of an antifogging agent (STO-405 manufactured by Marubishi Yuka Kogyo Co., Ltd.) were melted in a Banbury mixer. The resin composition prepared by kneading was used as the resin composition constituting the surface layer.

(2) Preparation of intermediate layer thermoplastic resin composition 50 parts by weight of the propylene-ethylene random copolymer PP-1 and the copolymer (1) 30 obtained in Reference Example 1
Parts by weight and petroleum resin (P-12 manufactured by Arakawa Chemical Co., Ltd.)
5) A thermoplastic resin composition prepared by melt-kneading 20 parts by weight with a Banbury mixer and further melt-kneading with a uniaxial extruder was used as the thermoplastic resin composition constituting the intermediate layer.

(3) Production of stretch film for packaging The obtained surface layer resin composition and intermediate layer thermoplastic resin composition were respectively used as inner and outer layer extruders and core layers of a three-layer inflation film processing machine manufactured by Placo Co., Ltd. Supply to the extruder,
Die temperature 200 ℃, blow ratio 4.5, take-off speed 20m
By processing at a rate of 1 / min, the thickness composition ratio becomes inner layer / core layer /
A stretch film for packaging having an outer layer order of 25% / 50% / 25% and a total thickness of 13 μm was manufactured. Table 5 shows various characteristic values of the obtained stretch film for packaging.

<Example 2> The procedure of Example 1 was repeated except that the copolymer (2) obtained in Reference Example 2 was used in place of the copolymer (1). A stretch film for packaging having a core layer / outer layer order of 25% / 50% / 25% and a total thickness of 13 μm was produced. Table 5 shows various characteristic values of the obtained stretch film for packaging.

<Comparative Example 1> The procedure of Example 1 was repeated except that the copolymer (3) obtained in Reference Example 3 was used instead of the copolymer (1). A stretch film for packaging having a core layer / outer layer order of 25% / 50% / 25% and a total thickness of 13 μm was produced. Table 5 shows various characteristic values of the obtained stretch film for packaging.

[0088]

[Table 5] The analysis items shown in Table 5 were performed by the following method.

(1) Transparency (Haze) Measurement was performed according to ASTM D1003. The smaller this value is, the better the transparency is.

(2) Heat resistance (heat resistant temperature) A film to be evaluated is brought into contact with a hot plate for heat sealing of a commercially available hand-type tray packaging machine (polywrapper manufactured by ARC Co., Ltd.) for 2 seconds to open a hole. I saw whether or not. This was carried out by changing the temperature of the heat sealing hot plate, and the maximum hot plate temperature at which no holes were formed in the film was detected and set as the heat resistant temperature. The higher this value is, the better the heat resistance is.

(3) Cutting property In packaging of a polystyrene foam tray using a commercially available push-up tray automatic packaging machine (AW2600AT-III.PE manufactured by Terraoka Seiko Co., Ltd.), folding of the film at the time of film cutting and The adhesion between the films was judged as follows. ◯: Folding of the film is small, and the adhesion between the films on the bottom of the tray is good. X: The film is greatly folded and the adhesion between the films on the bottom of the tray is poor.

(4) Whitening resistance The film to be evaluated was heated in a heating oven at 40 ° C. for 14 days to obtain a value obtained by subtracting the haze value measured immediately after producing the film from the haze value measured. The smaller this value is, the better the whitening resistance is. The haze value was measured according to ASTM D1003.

[0093]

As described above, the present invention provides films suitable for a stretch film for packaging having excellent whitening resistance, and a stretch film for packaging having excellent whitening resistance. The packaging stretch film obtained by the present invention is also excellent in transparency, heat resistance and cuttability, and the industrial utility value of the present invention is extremely high.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hidezumi Hozumi             Sumitomo Chemical Co., Ltd. 1-5 Anezaki Kaigan, Ichihara City, Chiba Prefecture             Business F-term (reference) 3E086 AB02 AC22 AD17 BA04 BA15                       BB22 BB41 BB58 CA17 CA18                       CA22 CA25                 4F071 AA12 AA12X AA15 AA15X                       AA16 AA17 AA18 AA19 AA20                       AA20X AA21 AA21X AA22                       AA22X AA39 AA39X AA40                       AA43 AA50 AA51 AA54 AH04                       BB06 BC01                 4F100 AK03A AK07A AK64A AK68                       AL03A AL05A AT00B BA02                       GB15 JA04A JA06A JA20A                       JJ03 JN01 JN08 YY00A                 4J002 AC02W BB02W BB03X BB11W                       BB12X BB16W BB17X BC02W                       BC02X BK00W CB00X CF00X                       CG00X CH07X CL00X GG02

Claims (3)

[Claims] 1. Films having a layer containing the following olefin polymer. Olefin polymer: An olefin polymer in which X defined in formula (1) satisfies the condition of formula (2). X = [A (T2M) -A (T2C)] / [| (T2A-T2B) |] Formula (1) X ≧ 0.02 Formula (2) A (T2M), A (T2C) in Formula (1) above ), T
2A and T2B are the olefin polymer, one propylene polymer selected from the group consisting of the following (A) and (B), and a test composition comprising the olefin polymer and the propylene polymer. A value obtained by using the measured result of the measured pulse NMR,
(T2M) and A (T2C) are T2 of the test composition.
It is a value obtained by definite integration of a curve obtained by plotting the relaxation time on the vertical axis and the weight fraction Pa of the olefin polymer in the test composition on the horizontal axis in the range Pa = 0 to 1. . However, A (T2M) is the T2 relaxation time of the test composition of each composition obtained by pulse NMR measurement for a plurality of test compositions having different weight fractions Pa (that is, measured T2 relaxation time: T2M ( Pa)) and plot 3
It is a value calculated for a curve based on the multiple regression equation obtained by the secondary regression, and A (T2C) is the T2 relaxation time obtained by pulsed NMR measurement for the propylene polymer, and for T2A and the olefin polymer. T2B, which is the T2 relaxation time obtained by pulsed NMR measurement
Is used to plot the T2 relaxation time (that is, the calculated T2 relaxation time: T2C (Pa)) obtained by the equation (3),
It is a value calculated for a curve based on the multiple regression equation obtained by the cubic regression. Here, PvA (Pa) is a value calculated by the equation (4). VA and VC (Pa) contained in the formula (4) were observed in the range of 70 to 150 μs of free induction decay obtained by pulsed NMR measurement of the propylene polymer and the test composition of each composition. It is the volume fraction of the component. (A) 23 at a load of 2.16 kg
Melt flow rate at 0 ° C is 12.0 ± 3.0g / 1
0 minutes, the main peak temperature (melting point) based on the melting of crystals obtained by measurement with a differential scanning calorimeter according to JIS K 7121 is 160 ± 3 ° C., and JIS K 71
22. The melt flow rate at 230 ° C. in a propylene homopolymer (B) load of 2.16 kg having a heat of fusion of crystals of 100 ± 5 J / g measured by a differential scanning calorimeter in accordance with No. 22 is 1.0. ± 0.6 g / 10 minutes, J
The main peak temperature (melting point) based on melting of the crystal obtained by measurement with a differential scanning calorimeter according to IS K 7121 is 135 ± 2 ° C., and measured with a differential scanning calorimeter according to JIS K 7122. The heat of fusion of the obtained crystals is 6
Propylene-ethylene random copolymer having 0 ± 5 J / g 2. A layer containing the olefin polymer,
(I) Thermoplastic resins 1 to 9 other than the olefin polymer
The film according to claim 1, which is a layer containing 9% by weight and (ii) 99 to 1% by weight of the olefin polymer. 3. A stretch film for packaging, which comprises the film according to claim 1 or 2.