JPS6185457A - Propylene copolymer composition - Google Patents

Abstract

PURPOSE:The titled composition useful as a covering layer for a plural layer film, having improved slip characteristics, transparency, and low-temperature heat sealability, obtained by blending a propylene-ethylene random copolymer resin with a vinylene fluoride polymer. CONSTITUTION:(A) 100pts.wt. one or more (i) a resins consisting of a propylene- ethylene random copolymer resin having 3-8wt%, 4-6wt% ethylene content and 0.5-50g/10 minutes melt flow rate, and (II) propylene-ethylene-butene-1 random copolymer resin having 0.5-wt%, preferably 1-4wt% ethylene content, 3-25wt%, preferably 5-20wt% butene-1 content, and 0.5-50g/10 minutes melt flow rate is blended with (B) 0.1-2pts.wt., preferably 0.2-1pt.wt. vinylidene fluoride polymer having 0.25-5 times as much melt flow rate as that of the component A and >=150 deg.C melt peak temperature by DSC.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention provides a slip 4? The present invention relates to a composition which has significantly improved properties and has good transparency and low-temperature heat sealability.

[Conventional technology]

Multilayer films, such as heat-sealable biaxially oriented polypropylene films, are widely used as overlapping materials for foods, cigarettes, cassette tapes, etc. due to their properties such as transparency and rigidity. With the recent development of high-speed self-spindle packaging machines, the required quality of films suitable for automatic packaging has become more sophisticated than ever before. The most important performance requirement is low-temperature heat sealability. As a method for imparting low-temperature heat sealability,
There is a known method of dissolving a low melting point substance in an organic solvent and coating it on a stretched film substrate.

However, although films made by coating methods can have low-temperature heat-sealing properties, their sealing strength is weak, and it is elegant to completely eliminate the solvent used during coating, and is separate from the stretched film manufacturing process. It has drawbacks such as relatively high manufacturing costs because the coating is made using koji during the process. In order to avoid the high cost of such coating methods, resins that provide low-temperature heat-sealability when producing biaxially oriented polypropylene films,
For example, a method in which propylene-ethylene random copolymer resin or propylene-ethylene-butene-1 random copolymer resin is laminated and then stretched 2+111 is often practiced. Also simplified f
This is a great way to get exposed.

However, even in such a method, film-to-film bonding may occur due to the stickiness of the wood grain component.

The defects include deterioration of film quality such as locking and slip properties, deterioration of slip properties between the film and the metal guide part of high-speed automatic packaging machines, and slip properties between the film and the hot plate of high-temperature parts of high-speed automatic packaging machines, etc. have.

Therefore, at present, a biaxially oriented polypropylene film that has low-temperature heat sealing properties suitable for high-speed automatic packaging and satisfies packaging suitability has not yet been developed.

[Problem that the invention seeks to solve]

The present invention aims to overcome the drawbacks of the prior art, that is, the lack of low-temperature heat-sealing properties and slip properties. This was done because it was found that the purpose was achieved and transparency was also maintained well.

[Failure to solve the problem]

That is, the present invention provides a propylene copolymer composition characterized by comprising the following components A and B.

Component A: propylene-ethylene random copolymer resin with an ethylene content of 3 to 8% by weight and an ethylene content of 0.5 to 8% by weight
100 parts by weight of at least one resin selected from propylene-ethylene-butene-1 random copolymer resins having a butene-1 content of 5% by weight and a butene-1 content of 3 to 25% by weight Component B: Vinylidene fufluoride polymer 0.1 ~2 parts by weight
It is.

[Effect]

The propylene-ethylene random copolymer (combined resin), which is one of the components A that can be used in the present invention, has an ethylene content of 3 to 8% by weight, preferably 4 to 6% by weight.

If the ethylene content is less than 3% (t%), the heat sealability will be poor and the material will not be suitable for high-speed automatic packaging.On the other hand, a polymer with an ethylene content of 8%/1% will have good heat sealability. Although it can be done, the stickiness and scratch resistance of the film are significantly reduced, and no improvement is expected even by adding component B, which will be described later.The melt flow rate of this product is preferably 0.5 to 50 t/10 min. , especially 1 to 20 y/1° min, especially 2 to 20 y/1° min.
1051/10 minutes is good.

In addition, the propylene-ethylene-butene-1 random copolymer resin, which can be used in the above-mentioned component A, has an ethylene content of 0.5 to 5% by weight, preferably 1 to 4% by weight, and The content of butene-1 is 3 to 25% by weight, preferably 5 to 20% by weight. If the ethylene content is less than 0.5% by weight or the butene-1 content is less than 3% by weight, the heat sealability will be poor and the material will not be suitable for high-speed automatic packaging. On the other hand, polymers with an ethylene content of more than 5% by weight or a butene-1 content of more than 25% by weight can provide good heat-sealing properties, but the film becomes sticky and has poor scratch resistance, which is also caused by the addition of component B, which will be described later. No improvement is expected. In addition, the melt flow rate of this material is preferably 0.5 to 50/710 minutes, especially 1 to 2051/10 minutes, especially 2 to 1/10 minutes.
top/l.

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Furthermore, the vinylidene fluoride-based polymer as the component B that can be used in the present invention includes not only vinylidene fluoride homopolymers but also vinylidene fluoride and α-olefins, such as ethylene, propylene, monofluoroethylene, and difluoride. Copolymers with fluorinated ethylene, trifluorinated ethylene, tetrafluorinated ethylene, etc. are suitable. The melt flow rate h of this product is 0.25 times the melt flow rate of component A above.
A value within the range of 5 times, particularly 0.5 times or more, is preferred from the viewpoint of appearance when used in a product film. Further, it is preferable that the melting peak temperature measured by DSC is in the range of 150° C. or higher, especially 155° C. or higher, particularly 160° C. or higher, from the viewpoint of slip property at high temperatures.

The amount of component B added to 100 parts by weight of the above Alt content is 0.1 to 2 parts by weight, preferably 0.2 to 1 part by weight. If the addition of component B is less than 0.11 parts by weight, the effect of improving suitability for high-speed automatic packaging will be low, and if the addition exceeds 2 parts by weight, it will not only impair the transparency, which is the original property of the biaxially stretched film. , low-temperature heat sealability also deteriorates.

In the present invention, additional components can be added in addition to these essential components. For example, if 5 to 45 parts by weight of crystalline butene-1 polymer is added to 100 parts by weight of the above-mentioned components, low temperature Heat sealability can be further improved. As the crystalline butene-1 polymer, butene-1
In addition to homopolymers of 1, there are copolymers of butene-1 and other α-olefins, such as ethylene and propylene, whose melt flow rates are as high as 1 at the same temperature in the range of 180 to 300°C. From the viewpoint of transparency, it is preferable that the melt flow rate be equal to or larger than the melt flow rate of the input component.

The composition of the present invention is generally prepared by mixing the above-mentioned A and B components in a mixer such as a Henschel mixer, pre-goo, or ribbon blender, and then kneading the mixture in an extrusion type mixing machine or the like. . At this time, a master patch is prepared in which component B is mixed in a larger amount after a predetermined amount, and this is added to component A during molding.
It may be used after diluting for 4 minutes. Note that it is also possible to adopt a method in which a mixture of components A and B is melted for the first time in the molding stage to form a composition.

The composition of the present invention is most suitable for use in a coating layer of a biaxially oriented propylene polymer film. At this time, the method of melting and co-extruding the composition of the present invention on one or both sides of the propylene-based polymer resin of the base material layer to form a sheet, and biaxially stretching the sheet, is a method for producing a low-edge heat-sealing composition. This is preferred because it can be easily and uniformly and thinly laminated, but it is also possible to adopt a method in which the composition of the present invention is melt-extruded onto an unstretched or uniaxially stretched base resin sheet.

Of the biaxial stretching, longitudinal stretching is first performed using the difference in peripheral speed of the rolls. That is, 90-140°C, preferably 105-140°C
Stretched 3 to 8 times, preferably 4 to 6 times, at 135°C, then 3 to 12 times laterally in tenter open;
Preferably it is stretched 6 to 11 times.

In order to prevent heat shrinkage during heat sealing, it is desirable to heat set at 120 to 170° C. following lateral stretching.

Furthermore, corona treatment may be performed for the purpose of promoting printability and bleeding of the antistatic agent.

The thickness of the composite biaxially stretched film thus obtained is determined depending on the intended use, but is usually in the range of 5 to 200 microns, preferably 15 to 60 microns.

The thickness of the composition layer of the present invention is 0.2 to 5μ, preferably 0.
．． The thickness is preferably 3 to 2μ.

〔Example〕

The evaluation method is as follows.

+l) Haze A Measurement was carried out by stacking four films in accordance with STM-D-1o o a.

(2) Slip property Measured according to the static friction coefficient measurement method of ASTM-D-1894. The slip property between films at high temperatures was measured using a slip tester equipped with a heater so that the film could be set at a predetermined temperature. The slip property with metal was measured by measuring the slip property of a Teflon-coated iron plate and a film.

(3) Blocking property The two films were stacked and placed between two glass plates so that the contact area was 1 Oct+i, and after being left in an atmosphere at 40°C for 7 days under a load of 50 f/-, Schopper type test was performed. The sample was peeled off using a machine at a tensile speed of soom/min, and the maximum load was read and measured.

(4) Heat-sealability Using a heat-sealing bar of 5mIII x 200cm, at each set temperature, the heat-sealing pressure is 1 to 9/-, and the heat-sealing time is 0.5 seconds. A sample was cut out and pulled using a Schopper type testing machine at a tensile rate of 500 cm/min, and the maximum load was read and measured.

(5) Melt flow rate 23 (1, 2, 16
Measured using Kp load.

(6) Melting point Sample @ using PerkinElmer DSC-1 model
s, o my, and the peak of the melting curve obtained by melting at a temperature decreasing and temperature increasing rate of 10° C./min was adopted.

Examples 1 to 2 Polypropylene with a melt flow rate of 2.3 f/10 min and 96% AE was used as the base material layer, and ethylene was used as the low-temperature heat-sealing resin for the surface layer. 2% by weight, butene-1 content 12% by weight, melt flow rate 6, Oy/1
100 parts by weight of ethylene-propylene-butene-1 random copolymer with a melt flow rate of 4.1P/1
At 0 minutes, 0.2 parts by weight and 0.4 parts by weight of vinylidene fluoride polymer having a melting peak temperature of 168.5° C. by DSC were added.

In addition, as an antioxidant, 2,6-di-t-butyl-p
- 0.10 parts by weight of cresol and 0.05 parts by weight of calcium stearate as a hydrochloric acid catching agent were added, and after mixing, the mixture was pelletized. These compositions were laminated under the following conditions and sequentially biaxially stretched to obtain a biaxially stretched polypropylene composite film.

The base material layer polypropylene and the surface layer composition were each extruded using a 115 m diameter, 35 m diameter extruder using a 3' Hiroshi die.
A sheet was formed by melt coextrusion at 240° C. to form a three-layer structure of surface layer composition/polypropylene/surface layer composition. Subsequently, the film was stretched 5 times in the longitudinal direction at 115° C. using the difference in peripheral speed of the rolls. Next, the film was stretched 10 times in the single yellow direction in a tenter open at 160°C, heat set at 150°C, and then one side of the film was subjected to corona discharge treatment to obtain a biaxially stretched composite film. Thickness configuration is 1μ/2
It was 2μ/1μ.

Comparative Examples 1-2 ゛ In order to compare with Examples 1-2, the same ethylene-propylene looptene as in Examples 1-2 was added, and 1 silica (Siroid 244 manufactured by Fuji Davison) was added to 100 parts by weight of the random copolymer. 0.2 parts by weight and 0.4 parts by weight were added to obtain the same biaxially stretched composite films as in Examples 1 and 2.

Example 3 Ethylene i as a low-temperature heat-sealable resin for the surface layer
i5.3i[-%, melt flow rate 5.8ri710
A biaxially stretched composite film was produced in the same manner as in Example 2, except that the same amount of ethylene-propylene random copolymer was used.

Example 4 Fabric Example 1 as a low-temperature heat-sealable resin for the surface layer
~100 parts by weight of the same ethylene-propylene-butene-1 random copolymer as in 2 was added with a melt flow rate of 2.6f.
/10 minutes, melting peak diopter by DSCK was 173.7℃
0.3 parts by weight of vinylidene fluoride polymer, and crystalline polybutene with a melt flow rate of 48 t/10 min.
A biaxially stretched composite film was produced in the same manner as in Example 1 by adding 15'+i parts of 1.

Comparative Example 3 A biaxially stretched composite film was produced in the same manner as in Example 4, except that silica (Siroid Z44 manufactured by Fuji Devin Co., Ltd.) was used instead of the vinylidene fluoride polymer in Example 4.

The evaluation results for films made on each side are shown in Tables 1 and 2.

(The following is a blank space) [Effects of the Invention] As is clear from Tables 1 and 2, the film using the composition of the present invention has the blocking properties necessary for high-speed automatic packaging without impairing transparency and heat-sealing properties. It can be seen that the slip properties are significantly improved.

Claims (1)

[Scope of Claims] A propylene copolymer composition characterized by comprising the following components A and B. Component A: propylene-ethylene random copolymer resin with an ethylene content of 3 to 8% by weight and an ethylene content of 0.5 to 8% by weight
100 parts by weight of at least one resin selected from propylene-ethylene-butene-1 random copolymer resins having a butene-1 content of 5% by weight and a butene-1 content of 3 to 25% by weight Component B: Vinylidene fluoride polymer 0.1 to 25% by weight 2 parts by weight