JP2000351183A - Heat-shrinkable film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide superior high speed sealing properties, heat-shrinkability and the like and reduce residual corners by laminating and integrating surface layers composed of a polypropylene resin having a specified elusion amount at a specified temperature and a specified weight-average molecular weight of an elusion component based on the cross fractionation process on both faces of an intermediate layer of a lenear low density polyethylene of a specified density. SOLUTION: A resin composition constituting an intermediate layer or a surface layer is melt kneaded by respective three extruders and coextruded by a multilayer T-die or the like to constitute an intermediate layer of 0.880-0.935 g/cm3 linear low density polyethylene. A non-oriented multilayer sheer formed of polypropylene resin sheets havring 1-70 wt.% elusion amount at 70-80 deg.C and the 250,000-500,000 weight-average molecular weight of an elusion component by the cross fractionation process and laminated in both faces of the intermediate layer is manufactured. The sheet is cooled and set, and its temperature is raised up to a orientable temperature, and then the sheet is oriented vertically and horizontally to a given scale factor by the tenter orientation process or the tubular orientation process to manufacture a film. Thus the film of superior high speed sealing properties, heat shrinkability, flexibility and the like in which residual corners are reduced to small numbers is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-shrinkable film having excellent impact resistance, flexibility, heat-shrinkability and high-speed heat sealability.

[0001]

2. Description of the Related Art Conventionally, polyvinyl chloride resin, polypropylene resin, polyethylene resin and the like have been used as a resin constituting a heat shrinkable film. And
Polyvinyl chloride-based heat-shrinkable films have very good shrinkage and mechanical properties, but have many problems in terms of their effect on the environment. Polypropylene-based heat-shrinkable films are suitable for high-speed packaging because of their excellent transparency and heat-sealing properties and the stiffness of the film, but are inferior in impact resistance. There has been a problem that the film often breaks during line or transportation.

Therefore, in order to improve the impact resistance, a polyethylene resin film is laminated and integrated on both sides of a polyethylene resin film to form a multilayer structure, thereby improving the impact resistance and improving flexibility and finish quality. Various good heat-shrinkable films have been proposed (JP-A-58-166049, JP-A-63-2144).
No. 46, JP-A-64-1535, JP-A-2-
No. 1257334).

However, when the above-mentioned multilayer heat shrinkable film is used in a high-speed automatic packaging machine, the high-speed automatic packaging machine is applied with high tension by a seal bar heated to a high temperature, so that the film is pulled before it is solidified. As a result, there has been a problem that a strong heat seal cannot be performed, or that a melt break occurs.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a heat shrinkable material which is excellent in high-speed heat sealability, heat shrinkage, impact resistance and flexibility, and has excellent finish quality with little corner residue. Provide a film.

[0005]

The heat-shrinkable film of the present invention comprises a linear low-density polyethylene having a density of 0.880 to 0.935 g / cm ³ and a polypropylene resin having a melting point of 145 ° C. or lower, if necessary. The elution amount at 70-80 ° C. by the cross fractionation method is 1-7 on both surfaces of the intermediate layer obtained by adding
0% by weight and the weight average molecular weight of the eluted component is 250,000-
A surface layer made of 500,000 polypropylene resin is laminated and integrated.

The linear low-density polyethylene constituting the intermediate layer is not particularly limited as long as it has been conventionally used for a heat-shrinkable film. Copolymers may be used, and these may be used alone or in combination.

[0007] Examples of the copolymer with the other monomer containing ethylene as a main component include a copolymer of ethylene and an α-olefin. Examples of the α-olefin include propylene, 1-butene, and 1-butene. -Pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like.

[0008] The density of the linear low-density polyethylene is:
If it is too high, the transparency will be reduced, and if it is low, the resulting heat-shrinkable film will have low stiffness and cannot be used for high-speed packaging, so it is limited to 0.880 to 0.935 g / cm ³ . The density of linear low-density polyethylene is
It was measured in accordance with JIS K6760.

When the melt index of the linear low-density polyethylene is high, the heat-shrinkability of the resulting heat-shrinkable film may decrease. 0.3 to 10 g / 10 min is preferable, and 1 to 5 g / min.
10 minutes is more preferred. The melt index of the linear low-density polyethylene refers to a value measured at a temperature of 190 ° C. and a load of 21.168 N based on JIS K7210.

The intermediate layer has a melting point of 14 in order to improve the degree of fusion between the intermediate layer and a surface layer to be described later and to improve the high-speed heat sealing property of the heat-shrinkable film obtained.
A polypropylene resin having a temperature of 5 ° C. or lower (hereinafter referred to as “polypropylene resin (A)”) may be contained.

The polypropylene resin (A) is not particularly limited as long as it has a melting point of 145 ° C. or less. For example, a propylene-ethylene-butene ternary random copolymer or propylene as a main component Copolymers with α-olefins and the like may be mentioned, and these may be used alone or in combination. However, it is preferable to use the same type as the polypropylene resin used for the surface layer described later.

It should be noted that α-
The copolymer with the olefin may be any of random, block, and random block copolymers.
-As the olefin, ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1
-Octene and the like, and an ethylene-propylene random copolymer is preferable.

If the melting point of the polypropylene resin (A) is high, the resulting heat-shrinkable film has low shrinkage at low temperatures.

When the polypropylene resin (A) is contained in the intermediate layer, if the content of the polypropylene resin (A) is large, the impact resistance of the obtained heat-shrinkable film may be reduced. If the amount is too small, the degree of fusion between the intermediate layer and the surface layer of the heat-shrinkable film may decrease, and the high-speed heat sealing property of the obtained heat-shrinkable film may decrease. Therefore, the intermediate layer is preferably composed of 70 to 95% by weight of the linear low density polyethylene and 5 to 30% by weight of the polypropylene resin (A).

The polypropylene resin constituting the surface layer (hereinafter referred to as “polypropylene resin (B)”) is not particularly limited as long as it has been conventionally used for a heat-shrinkable film. Examples thereof include homopolypropylene, propylene-ethylene-butene ternary random copolymer, and a copolymer of propylene with an α-olefin as a main component. These may be used alone or in combination.

It should be noted that the above-mentioned α-
The copolymer with the olefin may be any of random, block, and random block copolymers.
-As the olefin, ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1
-Octene and the like, and an ethylene-propylene random copolymer is preferable.

If the amount of the polypropylene resin (B) eluted at 70 to 80 ° C. by the cross fractionation method is large, the surface layer becomes sticky and the resulting heat-shrinkable film has low lubricity.
On the other hand, if the amount is small, the high-speed heat sealing property is reduced.
To 70% by weight.

Similarly, when the weight average molecular weight of the components eluted at 70 to 80 ° C. by the cross-fractionation method of the polypropylene resin (B) is high, the surface layer becomes sticky and the lubricity of the obtained heat-shrinkable film decreases. On the other hand, if it is low, the high-speed heat sealing property is reduced, so that it is limited to 250,000 to 500,000.

The above-mentioned cross fractionation method is a method of cross-analyzing the relationship between the crystallinity and the molecular weight of the polymer, and specifically, the o-distillation at 140 ° C. or at a temperature at which the polypropylene resin (B) is completely dissolved. After dissolving the polypropylene resin (B) in chlorobenzene, the solution is cooled at a constant speed, and a thin polymer layer is deposited on the surface of an inert carrier prepared in advance in the order of crystallinity and weight-average molecular weight. Next, the concentration of components eluted sequentially is detected by increasing the temperature continuously or stepwise, and the composition distribution (crystallinity distribution) is measured. This is referred to as temperature rise elution fractionation, and at the same time, sequentially eluted components are analyzed by high-temperature GPC to measure the molecular weight and molecular weight distribution.

In the present invention, the measurement is carried out using a cross-separation chromatograph (product name “CFC-T150A”, manufactured by Mitsubishi Chemical Corporation) having both a temperature-rise elution fractionation part and a high-temperature GPC part as a system. did.

In the intermediate layer and the surface layer, additives such as a lubricant, an antiblocking agent, an antistatic agent, an antifogging agent, an antioxidant, an ultraviolet absorber, and a crystal nucleating agent are added to the intermediate layer and the surface layer. You may add in the range which does not impair the physical property of a layer.

The lubricant is not particularly limited as long as it has been conventionally used for a heat-shrinkable film, and examples thereof include lauric amide, myristic amide, palmitic amide, stearic amide, and behenic amide. And higher unsaturated fatty acid amides such as saturated fatty acid amides, oleic acid amides and erucic acid amides, and alkylene bisstearic acid amides such as ethylene bisstearic acid amide.

The anti-blocking agent may have any of spherical or amorphous shapes.
Inorganic fine particles such as silica, zeolite, talc, kaolin, etc., cross-linked polymethyl methacrylate resin, cross-linked polystyrene resin, non-melting silicone resin, non-melting silicone rubber, silicone copolymer, amide resin, triazine ring-containing condensation resin, etc. Organic fine particles.

If the particle size of the anti-blocking agent is large, the transparency of the resulting heat-shrinkable film may be reduced. If the particle size is small, the effect of the addition may not be exhibited. ８8 μm is preferred.

As the antistatic agent and the antifogging agent, nonionic surfactants having high heat resistance are preferable.
Examples include fatty acid glycerin esters such as monoglycerin stearate and diglycerin stearate, fatty acid alkylamides such as diethanolamide, fatty acid alkylamines such as diethanolamine, and sorbitan fatty acid esters such as sorbitan monostearate.

Next, a method for producing the heat shrinkable film will be described. As the method for producing the heat-shrinkable film, a method for producing a multi-layer film which is widely used is used. For example, three extruders are prepared, and a resin composition constituting an intermediate layer or a surface layer in each of these extruders. And melt kneading, preferably by co-extrusion using a multilayer T die or a multilayer annular die, etc., to obtain an unstretched multilayer sheet in which a polypropylene resin sheet is laminated on both sides of a resin sheet constituting an intermediate layer. To manufacture. After the unstretched multilayer sheet is cooled and solidified, the temperature is raised again to a temperature at which the sheet can be stretched, and then a predetermined stretching ratio is obtained by a known stretching method, for example, a tenter stretching method or a tubular stretching method. To produce a heat-shrinkable film.

Among the above-mentioned methods for stretching the multilayer sheet, the tubular stretching method is preferred because the degree of stretching in the longitudinal and transverse directions of the multilayer film can be made uniform. However, when the tubular stretching method is used, it is necessary that the multilayer sheet is obtained by co-extrusion with a multilayer annular die.

The thickness of the multilayer sheet is 200 to 500 μm.
m, the stretching ratio in the machine direction and the transverse direction is preferably 2 to 10 times, the stretching speed is preferably 10 to 100 m / min, and the stretching temperature is preferably adjusted to 50 to 120 ° C. at the sheet temperature before stretching. The thickness ratio of the surface layer / intermediate layer / surface layer of the heat-shrinkable film produced as described above is 1/2 /
1 to 1/10/1 is preferred.

[0029]

The heat-shrinkable film of the present invention has a density in the intermediate layer.
0.880-0.935 g / cm ^ThreeLinear low density poly
Heat-shrinkability and resistance
Obtain a package with excellent impact resistance and flexibility, and with little corner residue
be able to.

Further, the heat-shrinkable film of the present invention has an elution amount at 70 to 80 ° C. of 1 to 70% by weight and a weight average molecular weight of the elution component of 250,000 to 50 on both surfaces of the intermediate layer by the cross separation method. Since it is made of polypropylene resin, it does not break inadvertently at the heat-sealed part even when used in a high-speed automatic packaging machine, thus ensuring sufficient heat-sealing. be able to.

The intermediate layer has a density of 0.880-0.
935 g / cm ³ linear low density polyethylene 70-9
When it is composed of 5% by weight and 5 to 30% by weight of a polypropylene resin having a melting point of 145 ° C. or lower, the heat shrinkability of the resulting heat shrinkable film at a low temperature, without impairing the impact resistance and the flexibility, is good. The degree of fusion between the layer and the surface layer can be improved, and the high-speed heat sealability of the obtained shrink film can be further improved.

[0032]

EXAMPLES (Example 1) As a resin constituting the surface layer,
Polypropylene random copolymer (elution amount at 70-80 ° C. by the cross fractionation method = 15% by weight, weight-average molecular weight of elution component at 70-80 ° C. by the cross fractionation method = 340,000,
(Ethylene component = 5% by weight, Melting point = 136 ° C.) A resin composition comprising 100 parts by weight and erucamide 0.05 part by weight is prepared, and as a resin constituting the intermediate layer,
Linear low density polyethylene (density = 0.896 g / cm
³ , a melt index = 2.0 g / 10 min, 1-octene content = 14.5% by weight), and a resin composition comprising 100 parts by weight and erucamide 0.05 part by weight is prepared.
These were supplied to three extruders, respectively, melt-kneaded, and co-extruded using a three-layer annular die to obtain a multilayer sheet having a thickness of 350 μm. The multilayer sheet had a surface layer laminated and integrated on both surfaces of the intermediate layer, and the thickness ratio of the surface layer / intermediate layer / surface layer was 1/3/1.

After the multilayer sheet was quenched once, it was supplied to a heating oven and heated to 110 ° C. Subsequently, it was simultaneously biaxially stretched 5 times vertically and 5 times horizontally by a tubular method to obtain a heat-shrinkable film having a thickness of 15 μm.

Example 2 As the resin constituting the intermediate layer, a linear low-density polyethylene (density = 0.920 g /
cm ³ , melt index = 1.0 g / 10 min, 1−
A heat-shrinkable film was obtained in the same manner as in Example 1, except that a resin composition comprising 100 parts by weight of octene (13.1% by weight) and 0.05 part by weight of erucamide was used.

Example 3 As a resin constituting the surface layer, a polypropylene random copolymer (amount of elution at 70-80 ° C. by the cross fractionation method = 9% by weight, a component eluted at 70-80 ° C. by the cross fractionation method) Weight average molecular weight = 39
10,000, ethylene component = 3.2% by weight, butene component = 8.7
(% By weight, melting point = 136 ° C.) A heat-shrinkable film was obtained in the same manner as in Example 1 except that a resin composition comprising 100 parts by weight of erucamide and 0.05 part by weight of erucamide was used.

Example 4 As a resin constituting the surface layer, a polypropylene random copolymer (amount of elution at 70-80 ° C. by the cross fractionation method = 15% by weight, and a component eluted at 70-80 ° C. by the cross fractionation method) Weight average molecular weight = 34
10,000 parts, ethylene component = 5% by weight, melting point = 136 ° C.) 50 parts by weight and polypropylene random copolymer (elution amount at 70-80 ° C. by the cross fractionation method = 10% by weight, elution at 70-80 ° C. by the cross fractionation method) Weight average molecular weight of component = 1
90,000 ethylene component = 3.7% by weight, melting point = 143 ° C.)
A heat-shrinkable film was obtained in the same manner as in Example 1, except that a resin composition comprising 50 parts by weight and 0.05 part by weight of erucamide was used. The resin composition had an elution amount of 13% by weight at 70 to 80 ° C by a cross fractionation method, a weight average molecular weight of the eluted component of 270,000, and a melting point of 140 ° C.

Example 5 As a resin constituting the intermediate layer, a linear low-density polyethylene (density = 0.896 g /
cm ³ , melt index = 2.0 g / 10 min, 1-
85 parts by weight of octene = 14.5% by weight), 15 parts by weight of a polypropylene random copolymer having a melting point of 136 ° C. (ethylene component = 5% by weight), and 0.1 part of erucamide.
A heat-shrinkable film was obtained in the same manner as in Example 1, except that the resin composition consisting of 05 parts by weight was used.

Example 6 As a resin constituting the intermediate layer, a linear low-density polyethylene (density = 0.920 g /
cm ³ , melt index = 1.0 g / 10 min, 1−
85 parts by weight of octene = 13.1% by weight), 15 parts by weight of a polypropylene random copolymer having a melting point of 136 ° C. (ethylene component = 5% by weight), and 0.1 part of erucamide.
A heat-shrinkable film was obtained in the same manner as in Example 1, except that the resin composition consisting of 05 parts by weight was used.

(Example 7) As a resin constituting the surface layer, a polypropylene random copolymer (elution amount at 70 to 80 ° C by the cross fractionation method = 9% by weight, elution component at 70 to 80 ° C by the cross fractionation method) Weight average molecular weight = 39
10,000, ethylene component = 3.2% by weight, butene component = 8.7
% By weight, melting point = 136 ° C.) A resin composition comprising 100 parts by weight of erucamide and 0.05 part by weight of erucamide was used, and a linear low-density polyethylene resin (density = 0. 896 g / cm ³ , melt index = 2.0 g / 10 min, 1-octene content = 1
A resin composition comprising 80 parts by weight of 4.5 parts by weight), 20 parts by weight of a polypropylene random copolymer having a melting point of 136 ° C. (ethylene component = 5% by weight), and 0.05 parts by weight of erucamide was used. Except for the above, a heat-shrinkable film was obtained in the same manner as in Example 1.

Example 8 As a resin constituting the surface layer, a polypropylene random copolymer (elution amount at 70 to 80 ° C. by the cross fractionation method = 15% by weight, elution component at 70 to 80 ° C. by the cross fractionation method) Weight average molecular weight = 34
10,000 parts, ethylene component = 5% by weight, melting point = 136 ° C.) 50 parts by weight and polypropylene random copolymer (elution amount at 70-80 ° C. by the cross fractionation method = 10% by weight, elution at 70-80 ° C. by the cross fractionation method) Weight average molecular weight of component = 1
90,000 ethylene component = 3.7% by weight, melting point = 143 ° C.)
A resin composition consisting of 50 parts by weight and 0.05 part by weight of erucamide was used, and as a resin constituting the intermediate layer, a linear low-density polyethylene resin (density = 0.89)
6 g / cm ³ , melt index = 2.0 g / 10
90 parts by weight of 1-octene = 14.5% by weight), 10 parts by weight of a polypropylene random copolymer having a melting point of 136 ° C. (ethylene component = 5% by weight), and 0.05 part by weight of erucamide. A heat-shrinkable film was obtained in the same manner as in Example 1 except that a resin composition consisting of In addition,
The elution amount of the entire resin composition constituting the surface layer at 70 to 80 ° C by a cross fractionation method was 13% by weight, the weight average molecular weight of the eluted component was 270,000, and the melting point was 140 ° C.

(Comparative Example 1) As a resin constituting the surface layer, a polypropylene random copolymer (elution amount at 70-80 ° C. by the cross fractionation method = 8% by weight, elution component at 70-80 ° C. by the cross fractionation method) Weight average molecular weight = 14
10,000, ethylene component = 3.5% by weight, melting point = 142 ° C.) 1
A heat-shrinkable film was obtained in the same manner as in Example 1, except that a resin composition comprising 00 parts by weight and 0.05 part by weight of erucamide was used.

(Comparative Example 2) As a resin constituting the surface layer, a polypropylene random copolymer (amount of elution at 70-80 ° C. by the cross fractionation method = 27% by weight, a component eluted at 70-80 ° C. by the cross fractionation method) Weight average molecular weight = 20
10,000, ethylene component = 2.4% by weight, butene component = 7.2
% By weight, melting point = 136 ° C.) A resin composition comprising 100 parts by weight of erucamide and 0.05 part by weight of erucamide is used, and a linear low density polyethylene resin (density = 0. 920 g / cm ³ , melt index = 1.0 g / 10 min, 1-octene content = 1
A heat-shrinkable film was obtained in the same manner as in Example 1 except that a resin composition comprising (3.1% by weight) and 0.05 part by weight of erucamide was used.

(Comparative Example 3) As a resin constituting the surface layer, a polypropylene random copolymer (elution amount at 70 to 80 ° C by the cross fractionation method = 8% by weight, elution component at 70 to 80 ° C by the cross fractionation method) Weight average molecular weight = 14
10,000, ethylene component = 3.5% by weight, melting point = 142 ° C.) 1
A resin composition consisting of 00 parts by weight and 0.05 part by weight of erucamide was used, and a linear low-density polyethylene resin (density = 0.89) was used as a resin constituting the intermediate layer.
6 g / cm ³ , melt index = 2.0 g / 10
85 parts by weight of 1-octene = 14.5% by weight), 15 parts by weight of a polypropylene random copolymer having a melting point of 136 ° C. (ethylene component = 5% by weight), and 0.05 part by weight of erucamide. A heat-shrinkable film was obtained in the same manner as in Example 1 except that a resin composition consisting of

Comparative Example 4 Polypropylene random copolymer (elution amount at 70-80 ° C. by the cross fractionation method = 9% by weight, weight-average molecular weight of components eluted at 70-80 ° C. by the cross fractionation method = 390,000, ethylene) Ingredient = 3.2% by weight,
A resin composition consisting of 100 parts by weight of butene component = 8.7% by weight, melting point = 136 ° C.) and 0.05 part by weight of erucamide is supplied to an extruder, melt-kneaded, and 350 μm thick by a circular die. A single layer sheet was obtained.

After the single-layer sheet was once cooled rapidly, it was supplied to a heating oven and heated to 120 ° C. Subsequently, it was simultaneously biaxially stretched 5 times vertically and 5 times horizontally by a tubular method to obtain a heat-shrinkable film having a thickness of 15 μm.

Transparency of the heat-shrinkable film obtained above,
The lubricity, heat shrinkage, flexibility, high-speed packaging, finish quality, and seal strength were measured by the following methods, and the results are shown in Tables 1 and 2.

(Transparency) The haze of the heat-shrinkable film was determined by JI
It was measured according to SK6718.

(Lubricity) The dynamic friction coefficient of the heat-shrinkable film is represented by A
It was measured according to STM D 1894.

(Heat Shrinkability) The heat shrinkage of the heat shrinkable film was measured according to JIS K1709.

(Flexibility) The elastic modulus of the heat-shrinkable film is determined by AS
It measured according to TMD822.

(High-speed packaging) 8 cm × 8
A rectangular parallelepiped box having a size of cm × 25 cm and a weight of 1.6 kg was used. The high-speed automatic packaging machine used is sold by Tokiwa Industries under the product name "NEO618S", and the shrink tunnel is manufactured by Hanagata under the product name "P300".
The ones sold by the company were used.

The tunnel furnace length was 2 m and the tunnel passage time was 5 seconds. Then, the article to be packaged was packed using the high-speed automatic packaging machine in the following manner. First, a heat-shrinkable film in a flat state was sent out from a raw material, and holes were made at regular intervals in the width direction by a needle incorporated in a roll.
Then, the flat heat-shrinkable film was formed into a tubular shape by a former to wrap the object to be packaged.

Then, the central overlapping portion of the heat-shrinkable film is melt-sealed (center-sealed) at a temperature shown in Table 1 with a pair of heated rolls. The package is wrapped in a rough state by fusing and sealing (end sealing) at the temperature shown in Table 1, and the package wrapped by the heat-shrinkable film is supplied to the shrink tunnel for display. The heat-shrinkable film was shrunk by heating to the temperature shown in 1 and the object to be packaged was wrapped tightly with the film to obtain a package. The packaging conditions were a bag length of 380 mm, a packaging speed of 100 pieces / min, and six rows of needle holes.

According to the above-mentioned procedure, 500 articles were packaged, and the sealing failure rate of the obtained package was defined as high-speed packaging.

(Finish Quality) The finish of the package obtained by the above-mentioned high-speed packaging was visually observed and judged according to the following criteria. 1: The corner is small and there is no wrinkle. It is a very beautiful finish. 2: The corner is small but wrinkles remain slightly. There is no problem finish. 3: There is no wrinkle, but the corners are large and insufficient. 4: Defective product with large corners and many wrinkles.

(Seal Strength) The seal strength of an arbitrary portion at the center seal or end seal portion of the package obtained by the above high-speed packaging was measured in accordance with JIS Z1707. The tensile speed was 300 mm / min.

[0057]

[Table 1]

[0058]

[Table 2]

[0059]

As described above, the heat-shrinkable film of the present invention has the above-mentioned structure, and therefore, it is possible to obtain a package having excellent heat-shrinkability, impact resistance and flexibility, and excellent quality with little residual corner. As well as having excellent high-speed heat sealing properties, complete and reliable heat sealing can be performed even when used in a high-speed automatic packaging machine.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI theme coat ゛ (Reference) B29K 105: 02 B29L 9:00 F term (Reference) 4F100 AH03H AK07A AK07B AK07C AK63A AL03 AL05A BA03 BA06 BA10B BA10C CA19 JA03 JA13A JA13B JA13C JK10 JK13 JK17 JL12 YY00A YY00B YY00C 4F210 AA08K AA11 AE01 AG01 AG03 RC02 RG02 RG04 RG09 RG21 RG26 RG43

Claims (2)

[Claims] (1) a density of 0.880 to 0.935 g / cm;
On both sides of the intermediate layer of ³ of linear low density polyethylene, the elution amount of 70 to 80 ° C. by cross fractionation method 1-7
0% by weight and the weight average molecular weight of the eluted component is 250,000-
A heat-shrinkable film, wherein a surface layer made of 500,000 polypropylene-based resin is laminated and integrated. 2. The intermediate layer having a density of 0.880 to 0.93.
70 to 95% by weight of linear low density polyethylene of 5 g / cm ³ and a polypropylene resin having a melting point of 145 ° C. or less.
The heat-shrinkable film according to claim 1, comprising 30% by weight.