JPH02199144A - Polyolefin resin composition - Google Patents

Abstract

PURPOSE:To provide the title composition excellent in extrusion moldability and giving a molding excellent in nerve, impact strength, etc., by mixing a specified ethylene (co)polymer with a flexible elastomer, an ethylene/alpha-olefin copolymer, a crystalline polypropylene, etc., in a specified ratio. CONSTITUTION:15-45wt.% polymer selected from among a low-density polyethylene, a copolymer of ethylene with vinyl acetate or (ethyl or methyl) (meth) acrylate, an ionomer resin, etc., is mixed with 5-15wt.% flexible elastomer of a Vicat softening point <=60 deg.C, 20-55wt.% copolymer of ethylene with a 4-10C alpha-olefin having a density of 0.88-0.92g/cm<3> at 23 deg.C, a melt index of 0.5-5g/10min, a max. m.p. of 110-130 deg.C (as measured by differential scanning calorimetry) and a Vicat softening point of 60-95 deg.C and 10-40wt.% crystalline polypropylene or/and crystalline polybutane-1.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention has excellent extrusion moldability, heat sealability, impact strength characteristics, tensile strength characteristics, transparency, etc., and particularly improves the stiffness and impact strength of molded products. The present invention relates to a polyolefin resin composition that is excellent in contradictory properties at the same time.

Although these are not particularly limited, they are useful, for example, as a composition constituting at least one layer of a single layer or a multilayer for film molding.

[Conventional technology]

Conventionally, ethylene-propylene copolymer rubber (hereinafter referred to as EPR) was used to improve the thermal stability, strength at low temperatures, impact strength, etc. of crystalline polypropylene (hereinafter referred to as PP). A method of mixing one part has been proposed. However, in this method, the compatibility of PP and EPR is not necessarily good, and when processed into a thin film, the kneading is uneven, the surface is rough, the optical properties are greatly deteriorated, and the strength is insufficient. Therefore, only products with low commercial value could be obtained.

In addition, in order to improve these problems, a method of further mixing amorphous attack polypropylene has been proposed, but all of these are improvements based on PP, and when made into a thin film, still has problems.

Furthermore, as a composition to further improve the problems of these compositions, for example, Japanese Patent Publication No. 59-38976 discloses a ternary mixed composition of EVA, ethylene-α-olefin copolymer elastomer, and polypropylene. be. Even when processed into a thin film, this composition has superior stretchability compared to conventional polyolefin compositions, and produces films with excellent low-temperature shrinkability, heat resistance, heat sealability, mechanical strength, etc. There is. However, in today's world where the diversification of packaging and the speeding up of packaging are rapidly progressing, even films made from these compositions still have insufficient physical properties, and in particular, there is a problem that the film has low stiffness.

In addition, if you try to increase the stiffness by increasing the composition ratio of hard resins such as polypropylene, extrusion moldability and stretchability will decrease, the thickness will increase, tear strength will decrease, and there will be protrusions on the packaged items. If there is such a problem, it becomes easy to tear, or the impact strength decreases, making it easy to tear.

[Problem that the invention is trying to solve]

Based on the above, the object of the present invention is to avoid these problems, that is, to have excellent extrusion moldability and stretchability, high impact strength, high stiffness of the molded product, and heat sealability and tear strength. The object of the present invention is to provide a polyolefin resin composition having excellent properties, cold resistance, transparency, etc., preferably a polyolefin resin composition for film molding.

[Means to solve the problem]

According to the present invention, these problems are solved by: low density polyethylene, ethylene-vinyl acetate copolymer,
At least one polymer selected from the group consisting of ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylic acid copolymer, and ionomer resin ( A) Soft elastomer with a content of 15 to 45 wt% and a Vicat softening point of 60°C or less (B)
5-15wL% and density at 23℃ 0.880-0.920g/cm
3. Melt index is 0.5 to 5 g/10 minutes, maximum melting point by differential scanning calorimeter (DSC) is 110°C to 13
0°C and a Vicat softening point of 60°C to 95°C, a copolymer (C) of 20 to 55 wt% of ethylene and an α-olefin having 4 to 10 carbon atoms, crystalline polypropylene, crystalline polybutene- 1 or a mixed polymer (D) of 10 to 40 wL%, and a polyolefin resin composition comprising:

The present invention will be specifically explained below.

The polymer (A) used in the present invention is low density polyethylene,
EVA, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylate copolymer, ionomer resin, or a mixture thereof. .

Low density polyethylene has a melt index of 0°2~2
0, preferably 0.5-10, density 0. 915-0.
9: tOg/cd and Vicat softening point of 95°C or higher.

Ethylene copolymers contain monomers other than ethylene in an amount of 2 to 2.
12 mol%, M-1 is 0. 2 to 10. Among these, low-density polyethylene manufactured by high-pressure method,
EVA is particularly preferred, and these have a crystallinity of 40%, preferably 4, determined from the melting energy by DSC.
It is 5-65%.

Next, a soft elastomer with a Vicat softening point of 60'C or less (
B) refers to 1,2-polybutadiene, a soft copolymer of ethylene and one or more α-olefins selected from α-olefins having 3 to 12 carbon atoms, preferably the latter. In some cases, the latter may be further copolymerized with a small amount of a hydrocarbon having a polyene structure, such as dicyclopentadiene, 1,4-hexadiene, ethylidene-norbornene, etc. As an α-olefin, Propylene, butene-1, hexene-1
, 4-methylpentene-11octene-1, etc.
Preferred are propylene and butene-1.

The ethylene content in the copolymer is 20-93 mol%, preferably 40-90 mol%, more preferably 65-88 mol%.

These copolymers have a density of 0.900 or less, preferably 0.890 or less, and a Vicat softening point (ASTMD
1525 (value at a load of 1 kg)) is 60"C or less, and is generally substantially amorphous in a rubber-like region, and is a low-density polyethylene as the component A described above, or a low-density polyethylene as the component C described below. It is distinguished from those with crystallinity.Here, "substantially amorphous" refers to those with a crystallinity of 10% or less.

Preferred is a copolymer of ethylene and propylene or butene-1, or a copolymer containing a small amount of a compound having a diene structure, such as a random copolymer polymerized with a vanadium compound and an organoaluminium compound catalyst. The copolymer has a melt index of 0.1 to 10, preferably 0. 2 to 6 thermoplastic elastomers.

These are preferably supplied in the form of pellets that are not block-shaped like general non-vulcanized rubber and do not cause cold blowing, and have sufficient thermoplasticity to be able to be extruded into a film even when used alone. .

In addition, the polymer (C) is ethylene and α- having 4 to 10 carbon atoms.
It is a copolymer with olefin. Examples of the α-olefin include butene-1, hexene-1°hephtene-1,4-methylpentene-1, and octene-1, preferably 4-methylpentene-1 and octene-1. The ethylene content in the copolymer is 85-98 mol%, preferably 90-96 mol%.

The properties of these copolymers include a density at 23°C of 0.880 to 0.920 g/c, preferably 0.
．． 905-0,915, more preferably 0.907-0
．． 913, and the melt index is 0.5~
5 g/10 minutes is preferable, and these copolymers have a maximum melting point of 110°C to 1°C by differential scanning calorimetry (DSC).
30°C, and a Vicat softening point of 60°C to 95°C, which is clearly distinguished from a substantially amorphous material in a rubbery region such as component (B), and has a low degree of crystallinity. These usually have a crystallinity of 10 to 50%, preferably 15 to 45%.

Preferably, a copolymer of ethylene and 4-methylpentene-1 or octene-1 is used, for example, using a titanium compound and an organoaluminum compound catalyst, so-called medium-copolymerization.
It is a low-crystalline copolymer polymerized by a low-pressure method, and has a maximum melting point equivalent to that of ordinary linear low-density polyethylene, but a low Vicat softening point in the range of 60 to 95°C, making it suitable for stretching, etc. It has excellent moldability. These include, for example, Plastic Engineering Volume 11;
VLD as described in P59-62 ('85)
There is something like PH.

Moreover, the crystalline polypropylene and crystalline polybutene of component (D) are crystalline polymers with high isotacticity.

Polypropylene contains a propylene homopolymer or a copolymer of propylene and 7 mol% or less of α-olefin, and has an M·1 of 0.5 to 20.

Unlike low molecular weight liquid or waxy polybutenes, polybutene has a butene-1 content of 93 mol% or more and is a high molecular weight polybutene that also includes copolymers with other monomers. These are preferably relatively hard polymers with a Picat softening point of 100''C or higher.

The composition of the present invention comprises (A), (B), (
It consists of a mixed composition of C) and (D), and the range of the amount of component (A) is 15 to 45 wL%, preferably 20 to 40 wL%, and more preferably 25 to 35 wt%. Moreover, the range of the amount of component (B) is 5 to 15 wt%
and preferably 10 to 15 wL%. Further, the amount of component (C) ranges from 20 to 55 wL%, preferably from 25 to 45 wL%, and more preferably from 30 to 45 wL%.
It is 40wL%. Further, the range of the amount of component (D) is 1
The content is 0 to 40 wt%, preferably 20 to 30 wt%.

If the mixing amount of (C), which is a low-grade crystalline polymer component, is small, the mixture will not be able to exhibit a synergistic effect, and extrusion moldability, impact strength characteristics, cold resistance, transparency, etc. will deteriorate. do. The same thing will happen if the amount of (C) exceeds 55 wt%, and the stiffness and sealing properties of the molded product will also deteriorate.

Component (D) synergistically improves the tensile strength, impact strength, heat resistance, extrusion moldability, waist strength (modulus), and heat sealing temperature range of the mixed composition with other components, and particularly improves heat resistance, extrusion moldability. These effects have a large effect on properties such as elasticity, stiffness (modulus of elasticity), and heat-sealing temperature range.If the mixing amount is small, for example, the uneven thickness due to the flow characteristics during stretching and within the gouer becomes large. Moreover, the effect of improvement on the heat sealing temperature range and strength becomes smaller, and the heat resistance also decreases.

On the other hand, if the amount of component (D) is too large, extrusion moldability, transparency,
Cold resistance, impact strength, etc. are inferior.

In addition, component (A) is made of a specific low-density polyethylene or ethylene copolymer, and synergistically improves the extrusion moldability, heat sealability, transparency, etc. of the mixed composition with other components, In particular, when the amount of component (A) mixed is small, which has a large effect on heat sealability, transparency, etc.
Extrusion moldability may deteriorate, thickness unevenness may occur in the molded product, and the effect of improving the heat sealing temperature range and impact strength may be small.Also, if the amount of component (A) mixed is too large, the same problem may occur. However, the stiffness and heat sealing properties of the molded product also decrease.

Furthermore, if the amount of component (B) mixed is small, the synergistic effect as a mixture will not be exhibited, and extrusion moldability, impact strength characteristics, transparency, etc. will deteriorate. The same thing will happen if the amount of (C) mixed is too large, and the stiffness, heat sealing properties, heat resistance, etc. of the molded product will deteriorate.

Here, component (C) is the aforementioned four components (A), (B), (C
), (D) is preferably the component with the largest amount in the mixture. Mixing only component (A) and component (D) among the four components does not have good miscibility and compatibility; It is also difficult to expect the synergistic effects mentioned above.

In addition, component (B) and component (D), component (C) and component (
Mixing D) slightly improves the compatibility, but it is difficult to expect the synergistic effect described above, and in particular, the impact strength of the molded product is still insufficient. In addition, component (A), component (B), and component (
In the mixture of D), the mixture of component (A), component (C), and component (D), and the mixture of component (B), component (C), and component (D), compatibility and moldability are improved, A certain composition can improve either impact strength or waist strength, but it is not possible to improve both at the same time; attempting to improve impact strength will result in a decrease in waist strength, and attempting to improve waist strength will result in a decrease in impact strength. Put it away.

However, when component (C) is added to component (A), component (B), and component (D), these drawbacks are significantly improved,
It has good compatibility and moldability, and improves impact strength and waist strength at the same time, as well as transparency and heat sealability of molded products.
Tensile strength etc. can also be improved.

These reasons are thought to be due to complex interactions such as the crystal structure of each component of the mixture and the state of dispersion or orientation of the mixture.

For example, when component (A) is the main component, if the above components are melt-kneaded and extruded using an extruder with excellent cross-mixing ability to form a molded product, the internal components of component (D) dispersed in component (A) A situation may be considered in which the component (B) is dispersed in a complicated manner in the surrounding area, and the component (C) is dispersed and interacts so as to connect the dispersed components (D) with each other. When these are processed into a film or other molded product depending on the molding conditions to impart fluidity and orientation, the state of each component also changes.

For example, a relatively high temperature of 230~230°C suitable for the flow of component (D).
At 260°C, pass the above mixture through a small slit, e.g.
Extruded from a 5m long goo for films, sheets, etc.
When processed into a film by quenching after applying a certain draw ratio, it depends on the amount of hard component (D), but for example, when 30 wt% of crystalline polypropylene is mixed as component (D), , the crystalline polypropylene of component (D) has a structure in which the dispersed particles are finely oriented in the flow direction in the main component (A), and the components (B) and (C) are connected to the dispersed particles, It is thought that there may be cases where properties with significantly improved strength properties (particularly properties with improved impact strength and waist strength) are exhibited. At this time, since component (C) has a lower flow orientation than other components, it is considered that the oriented component and the non-oriented component are in a form as if they were reinforced with fibers.

The composition of the present invention can be freely used in the form of molded products, films, and other applications such as adhesives, and although it is not particularly limited, it is preferable to use it as a film.
For example, as a single body, it is molded from an annular goo by a conventional method such as air-cooling, water-cooling, etc., or by forming a film from a T-goo by a casting method, or by biaxially stretching these. be able to.

In addition, when molded as a multilayer composite as at least one of its constituent layers, it can be used as a film with processing stability, strength, sealing properties, and optical properties, and as an adhesive layer for the inner and outer layers. Applicable.

Furthermore, it has very good processability and is convenient for processing into molded products, such as films, which have been given a high degree of cold orientation.

Further, the composition of the present invention may be crosslinked using an organic peroxide crosslinking agent or energy rays, and the resulting crosslinked composition can have improved cold resistance and heat resistance in addition to the above-mentioned excellent properties. .

Further, as a preferable example of the composition of the present invention, 0.5 to 5 wL%, preferably 0.8 wL%, preferably 0.8 wL% of a nonionic surfactant having a boiling point of 200°C or higher as a liquid at room temperature is added to the composition of the present invention as an additive (E). When ~3 wt% is mixed, further preferable properties can be imparted synergistically.

These nonionic surfactants include polyhydric alcohols such as glycerin, sorbitol, pentaerythritol, and polyglycerin, linear saturated fatty acids with an alkyl group of 5 to 13 carbon atoms, or linear saturated fatty acids with an alkyl group of 17 to 21 carbon atoms. There are also esters with chain unsaturated fatty acids, such as diglycerin monooleate; and polyoxyethylene alkylphenyl ethers, such as polyoxyethylene nonyl ether or polyoxyethylene octylphenyl ether; As the ethylene fatty acid esters, esters with the above-mentioned fatty acids to which polyoxyethylene of 3 to 10 units of ethylene oxide is added are preferable, and these may be used alone or in combination.

These exhibit anti-blocking, anti-static, and anti-fog effects when made into a film, and are suitable as packaging films. In addition, these additives are easily dissolved in any of the components in the mixed resin component, and they gradually penetrate the surface layer from the inner layer and exhibit effects such as bleeding out. The low molecules that tend to be found in polymers are expelled all at once, so there is no problem with the surface becoming sticky, and the effect remains even after the surface is washed away.

Furthermore, alicyclic saturated hydrocarbons, rosins, petroleum fats, terpene resins, etc. may be added to the composition of the present invention as additives (F). Its preferred range is 0.5-l
Qwt%, more preferably 1 to 7wt%. These can be used alone or in combination, and when used in combination with the nonionic surfactant mentioned above, the bleeding speed of the nonionic surfactant can be adjusted and the sustainability of the effect can be further maintained. .

As described above, the composition of the present invention, especially when processed into a film, has excellent processing stability, strength, sealing properties, and optical properties, and can simultaneously improve impact strength and stiffness. In addition, by imparting a high degree of cold orientation, it is possible to give it low-temperature shrinkability, making it possible to use it in the same way as PVC shrink film, which is currently mainly used in the food shrink packaging field. Therefore, it is possible to create a film that is compatible with the diversification of packaging and the increase in packaging speed.

In addition to its use as a shrink packaging film, it is also used in stretch-shrink packaging films, other colored films, agricultural films, barrier films by adding a barrier layer as a multilayer, or shrink packaging films thereof, etc. It can be made into a multilayer film with a seed resin.

Moreover, it may be used as a molded product, and the same effect will be observed, and it will be particularly excellent in impact strength.

〔Example〕

EXAMPLES The present invention will be described in detail below with reference to Examples, but these are not intended to limit the scope of the present invention.

Note that the measurements and evaluations in this specification and the main text examples were carried out by the following methods.

(Evaluation method) Vika: ASTMD l 525-
Compliant with 58T.

A constant load of 1.000 g is applied to a needle with a flat tip with a cross-sectional area of 1 m", and the temperature is increased in a constant temperature oil bath at a rate of 50 °C per hour. The temperature at which the needle penetration depth reaches 1 m is called the Picat softening point ( ℃).

Epithelial layer 1Z4): Based on ASTM D 1505.

Measurements were made at 23°C using a precision gradient tube manufactured by Shibayama Seisakusho.

Measured on a film sample with a thickness of about 100 μm using a differential scanning calorimeter MODEL DSC2 manufactured by PerkinElmer.

The sample was rapidly heated to 150°C under nitrogen flow, held isothermally at this temperature for 5 minutes, and then heated to 150°C at a rate of 10°C/min.
The highest melting point was defined as the endothermic peak temperature when the sample was cooled to 100° C. and then reheated at a rate of 10'C/min. (Hereinafter abbreviated as M, P) Degree of conversion: The heat of fusion △H was measured by the above DSC, and Table 11 of Chemical Handbook Application & 1i (Chemical Society of Japan 4I) P, 836
．． Using the heat of fusion ΔHn of the 37 crystal components, the crystallinity (%
)=ΔH/ΔHnXIQQ.

MEL IN-S 10:ASTMD1
Compliant with 23B-52T.

Under the conditions of temperature 190"C2 extrusion load 2160±10g,
The weight of the resin constantly extruded was calculated into the number of grams extruded per 10 minutes. (Hereafter abbreviated as M,1,
) 40 meters at intervals of 20 m* in the two axes of the lum
The point thickness was measured, and when this was repeated three times in the machine direction, the thickness from the average thickness was defined as ±X%.

Measure the fold width of the room continuously over 20 meters, divide the difference R between the maximum and minimum by the average fold width, and multiply by 100.

varnish): Measured in accordance with ASTM D 1003-52.

Kudan Muyu K): Measured in accordance with ASTM D2457-70.

-kws": Measured in accordance with AS'r'MD-882.

1 mm+”); ASTM D-88
Measured according to 2.

Deposit 1” U Soshiko Kariniko LL: ASTMDl 709
-67.

Elmen'le: ASTM D1922-
Measured in accordance with 67.

Layer: 1 plate per layer; The temperature range of the bar type sealer (sealing range: 5 cm) was changed to show the temperature range in which the seal could be preferably achieved.

The lower limit is the temperature at which the seal will not peel and have a certain strength, and the upper limit is the temperature at which the seal will melt and break due to heat and will not have a certain seal strength.

The bar pressure was 1 kg/cd and the time was adjusted as appropriate.The resins used in the examples are described below.

a,: EVA (vinyl acetate content 3.5 mol%, M,
I, 2.0) a2: Low density polyethylene (LDPE) [M.

1.2,0, density 0. 918 g/cd, M, P
, 103°C] a3: Ethylene-ethyl acrylate copolymer (EEA
) (contains ethyl acrylate [5.0 mol%, M, I,
1. 5) a4 Near ionomer tree JJI (to) Cx-
f-ren-methacrylic acid copolymer Na neutralized type, methacrylic acid content 6.6 mol%, M, I, 1.
O1 neutralization degree 25%, saponification degree 50%] bl: Ethylene-α-olefin copolymer elastomer [α-olefin contains 15 mol% of propylene, random copolymerization of 2 wt% ethylidene norbornene, M,
1.0.45, density 0.88 g/cd, Vicat softening point 40°C or less] C3: Ethylene-α niolefin copolymer (VLDPE) with low crystallinity CM, I, 2
．． 2. Density 0. 910 g/c+J, Mikata Petrochemical Co., Ltd. Ultzex 1020L) c, ;VLDPE (M, I, 3.6, density 0°910
g/cd, Mikata Petrochemical Co., Ltd. Urtozex 1030L
) C3: VLDPE (M, 1.3.3, density 0°91
2 g/cd, Attain 4002 manufactured by Dow Chemical Company
] C,, VLDPE (M, I, 1.0, density 0°912
g/cd, Attain 40ca manufactured by Dow Chemical Company:
VLDPE (M, 1.0.9, density 0゜909g/
c+j, Sumitomo Chemical Excellen CNl0c, :VLD
PE (M, I, 0.8, density 0゜906 g/cd
, Union Carbide Knackflex DFDA
-1137NT) dI: Crystalline polypropylene (IPP) (4 wt% random copolymerization of ethyline, MFR 3.3, Vicat softening point 150°C) dI: Crystalline polybutene-1 (PB-1) (butene-
1 content 96 mol%, density 0. 905 g/d, M,
I, 1. 0) d3: IPP (5 wt% copolymerization of ethylene, MF
R7, O1 density 0. 900 g/cd, Vicat softening point 125°C] Example 1 Ethylene-vinyl acetate copolymer (EVA, a
+): 25 wt% and ethylene-α-olefin copolymer elastomer (b+) 15 wt%, crystalline ethylene-
α-olefin copolymer (VLDPE).

ex) 40wt%, crystalline polypropylene (dl) 20
By mixing wt% with a 65M diameter L/D-37 mixing head type screw, the cylinder part maximum temperature was 240.
The composition that has been plasticized and kneaded at
．． It is extruded through a 0.0 mm annular die, inflated by introducing air inside, and rapidly cooled to a diameter of 400 m.
A uniform film with a thickness of 50 μm was obtained. This film was continuously wound up into a roll.

Film forming processability is good and stable film formation is possible, and the thickness deviation in the width direction of the film is 2.5% above, and the variation in fold width is 4%.
It was uniform.

The properties of this film were as follows.

Haze: 1.6%, Gloss: 110%, Drop impact strength (
(hereinafter abbreviated as dirt strength): 41 kg-cm, waist strength (1
% tensile modulus, vertical/horizontal) 833/30 (kg/m
) Tensile strength: 4.5/4.0 (kg/m), the heat sealing range was wide from 110 to 260'C, and the heat resistance was also high.

Examples 2-1! In the same manner as in Example 1, a film was prepared with the composition shown in Table 1,
The properties obtained are shown in Table 2.

Table 1 In all cases, the processing stability of film formation is good, there is little thickness deviation in the width direction of the film, and there is a large improvement effect in dart strength and waist strength (1% tensile modulus).

In addition, each heat sealing temperature range is wide <110 to 260
℃, the seal strength is strong, and problems such as holes in the seal are not observed in this temperature range.

Examples 12 to 26 Using the same method as in Example 1, films were formed using the resin composition of Example 1 with the composition ratios changed as shown in Table 3, and the obtained properties are shown in Table 4.

As a result, the process stability of the film formation was good for all composition ratios, and thickness deviations and fold width fluctuations were small.

It is also seen that within this composition ratio range, it is possible to obtain a molded product that has excellent transparency and gloss, and is excellent in both dart strength and waist strength (1% tensile modulus), which are usually contradictory properties. Furthermore, within these composition ratio ranges, the heat sealing temperature range was wide (<110 to 260°C), and the sealing strength was strong.

In addition, when the orientation state of each composition component in the composition of Example 19 was examined using a polarized fluorescence method, it was found that although EVA, polypropylene, and ethylene-α-olefin copolymer elastomer were oriented in the flow direction, they were partially crystalline. It was observed that the ethylene-α-olefin copolymer was hardly oriented. The dart strength of this composition was 42 kg-d, which was the strongest among the compositions of Examples.

Examples 27 to 42 The compositions of Example 1 and Examples 12 to 26 (Table 3) were melt-plasticized using the same extruder as Example 1, and diglycerin was added as a liquid additive from the middle of the extruder. A composition in which 2.0 wt % of monooleate was injected and kneaded was extruded in the same manner and rapidly cooled to obtain an original fabric having a thickness of 90 μm. Subsequently, this original fabric was heated using hot air at 70″C, and the vertical size was increased by 3.2 times.
Air is blown into the inside at 4° width and cold stretched.
After folding, heat setting was performed using hot air at 40° C. to obtain a film having a thickness of 11 μm.

Table 5 shows the properties of the obtained film.

In all cases, the stability of film formation was good, and variations in thickness unevenness and fold width were also small.

In addition, despite the thickness of both films being as thin as 11 μm, the dart strength exceeds 30 kg-c, and the waist strength (1
% tensile modulus) (and tear strength was also very excellent. Also, each of these films had a wide heat sealing temperature range of 110 to 260°C, and the sealing strength was also strong. .Also, the obtained film is
Shrinkage rate at 60℃ 20-30%, heat shrinkage stress 100-1
50g/cj (vertical/horizontal average), it has sufficient low-temperature shrinkability as a shrink packaging film, and has excellent properties such as dart strength, waist strength, tensile strength, tear strength, transparency, and heat sealability. In combination, the film is extremely useful as a packaging film that can accommodate the diversification of shrink packaging and the increased packaging speed.

Comparative Examples 1 to 10 Films having the compositions shown in Table 6 were formed in the same manner as in Example 1, and the obtained properties are shown in Table 7.

Table 6 Table 8 As a result, regarding the film forming process stability, Comparative Example N [L7
There was a problem with everything except for the unevenness of the meat, which was not very good.

In particular, in Comparative Examples 1.2.3, the kneading was uneven and the optical properties (haze, gloss) were poor.

In addition, Comparative Examples 4,5,6,9 are difficult to handle because the film has low stiffness.

Furthermore, although the films of Comparative Examples 7, 8, and 10 had better optical properties than the others, they still had insufficient dart strength and stiffness.

The heat sealing temperature range is Comparative Example 1.2.3.8.10
was in the high temperature range of 160 to 230"C, and the strength was not very strong. Comparative example 4.5.6.9 was 10
Although it can be sealed in the low temperature range of 0 to 150"C, it has no heat resistance and is prone to holes.

Comparative Examples 11 to 20 Films having the compositions shown in Table 8 were formed in the same manner as in Example 1, and the properties of the obtained films are shown in Table 9.

All of the films had poor film-forming stability and only had large thickness deviations.

Further, although these films have relatively good compatibility of each constituent resin and good optical properties, they have low dart strength and low stiffness, making them difficult to handle.

Comparative Examples 21 to 30 Films were formed using the compositions of Comparative Examples 11 to 20 (Table 8) in the same manner as in Example 27 to obtain films with an average thickness of 11 μm. Table 10 shows the properties of the obtained film.

As a result, both films had poor film-forming stability.
Furthermore, the thickness of the film was also large. In addition, although these films have relatively good optical properties, their dart strength is low and their tear strength is also not very strong, so if you try to package contents with protrusions or increase the packaging speed, the film may tear. They were unusable because they had holes in them.

In particular, Comparative Examples 21, 25, 26, and 30 had a problem in that they were difficult to handle in addition to the above-mentioned problems because of their weak waist strength.

Among these, it is particularly useful as a composition for forming sheets and films.

〔Effect of the invention〕

As described above, the composition according to the present invention has excellent extrusion moldability, as well as excellent heat sealability, impact strength characteristics, tensile strength characteristics, transparency, and the like.

Claims (1)

[Claims] Low density polyethylene, ethylene-vinyl acetate copolymer,
At least one polymer selected from the group consisting of ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylic acid copolymer, and ionomer resin ( A) Soft elastomer with a content of 15 to 45 wt% and a Vicat softening point of 60°C or less (B) 5
~15wt% and density at 23°C of 0.880~0.920g/cm
^3, melt index is 0.5~5g/10min, maximum melting point by differential scanning calorimeter (DSC) is 110℃~1
30°C and a Vicat softening point of 60 to 95°C, 20 to 55 wt% of a copolymer (C) of ethylene and an α-olefin having 4 to 10 carbon atoms, crystalline polypropylene, crystalline polybutene-1 A polyolefin resin composition comprising: or 10 to 40 wt% of a mixed polymer (D) thereof.