JPS62212445A - Blocking-resistant ethylene polymer film - Google Patents

Abstract

PURPOSE:To provide the titled film having excellent blocking resistance, transparency and hue, by blending an ethylene polymer film with a mixture of hydrated aluminum silicate having a specified particle size and fired aluminum silicate. CONSTITUTION:Hydrated aluminum silicate (a) having an average particle size of 0.1-2mum, pref. 0.3-1.5mum (e.g. kaolin exhibiting a loss on ignition of 10-16wt% and contg. not more than 5wt% components other than Al2O3 and SiO2) is mixed with fired aluminum silicate (b) having an average particle size of 0.5-5mum, pref. 0.8-3mum (e.g., kaolin exhibiting a loss on ignition of not more than 2wt% and contg. not more than 5wt% components other than Al2O3 and SiO2) in a weight ratio of 10-95:90-5 to obtain a mixture (B). A film (A) composed of at least one ethylene polymer selected from the group consisting of ethylene copolymers mainly composed of medium/low-density PE, ethylene is blended with 0.01-1wt% (based on the amount of the component A) component B.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a blocking-resistant film based on an ethylene polymer film that is easily blocked as it is. More specifically, the present invention relates to a polyethylene resin film that has excellent anti-blocking properties, good transparency and hue, and extremely little clouding due to friction.

Conventional technology Conventionally, polyolefin films, especially those with a density of 0.94
It is known that additive-free films of medium-low density polyethylene with a density of less than 1/d and ethylene copolymers with an ethylene unit content of 70% by weight or more have a drawback of high blocking properties.

This blocking property makes it extremely difficult to separate the stacked films one by one, and becomes a significant hindrance in various operations from blown film forming to packaging.

In order to prevent such blocking, it is known that blending an inorganic anti-blocking agent is effective, and silica powder has been used as an anti-blocking agent in polyethylene films.

However, when silica powder is used as an anti-blocking agent, the transparency of the film decreases and
During handling, transportation, etc., the film is damaged by friction and becomes cloudy, resulting in a significant drop in the quality of the product film's appearance and a reduction in its commercial value.

Problems to be Solved by the Invention The purpose of the present invention is to improve the drawbacks of the conventional blocking-resistant ethylene polymer film using silica powder as an anti-blocking agent, and to provide good transparency and color. The object of the present invention is to provide an ethylene polymer film having excellent anti-blocking properties and extremely little clouding due to friction.

Means for Solving the Problems As a result of extensive research by the present inventors, a mixture of hydrated aluminum silicate and calcined aluminum silicate having a specific particle size was added to an ethylene polymer film that was easily blocked as it was. It has been found that the above objective can be achieved by blending in the ratio of 1 to 2, and the present invention has been completed based on this finding.

That is, the present invention provides for a resin film selected from medium-low density polyethylene, an ethylene-based copolymer mainly composed of ethylene, and a mixture thereof, C) hydrated silicic acid having an average particle size of 0.1 to 2 μm. A mixture of aluminum and (B) calcined aluminum silicate with an average particle size of 0.5 to 5 μm, with a weight ratio of (A) and (B) in the range of 10:90 to 95:5, is added to the resin. The object of the present invention is to provide a blocking-resistant polyethylene resin film characterized in that it is blended in a proportion of 0.01 to 1% by weight based on the weight.

The film base material used in the present invention has a density of 0.94
Ethylene homopolymer or ethylene-based copolymer mainly composed of ethylene (ie, ethylene unit is 70% by weight), or a mixture thereof, which causes significant blocking unless an anti-blocking agent is added. It is.

Examples of the ethylene copolymer include ethylene-α-
Olefin copolymer, ethylene-vinyl acetate copolymer,
Ethylene-methyl methacrylate copolymer or its metal salt substituted product, ethylene-ethyl acrylate copolymer or its metal salt substituted product, etc.

An example of this is an ethylene copolymer that easily blocks when formed into a film by itself. In the present invention, as an anti-blocking agent, hydrated aluminum silicate with an average particle size of 0.1 to 2 μm and an ethylene copolymer with an average particle size of Calcined aluminum silicate of 0.5 to 5 μm is used.

The hydrous aluminum silicate usually has a heat loss of 10 to 16 weight It', AI, Q, , 810
! Kaolin whose other components are 5-fold US or less is used.

Examples of such products include ALF aluminum silicate 17o600 and 900 (both KNG
Manufactured by ELHARD, product name), etc.

In the present invention, it is necessary that the average particle size of the hydrated aluminum silicate is in the range of 0.1 to 2 μm, preferably 0.3 to 1.5 μm. This average particle size is 0.1μ
If it is less than m, the anti-blocking effect will be low, and if it exceeds 2 μm, the surface of the film will become rough, which is not preferable.

On the other hand, as calcined aluminum silicate, the thermal loss is usually 2% by weight or less, and Al□Os? Kaolin containing 5% by weight or less of components other than 81 false is used. Such items include SAT Engineering NTQN Aluminum Silicate 5,
5special, WH Engineering TE'rEX (both I!: manufactured by NGIiLHARD, product names), etc.

In the present invention, it is necessary that the average particle size of the calcined aluminum silicate is in the range of 0.5 to 5 μm, preferably 0.8 to 3 μm. If the average particle size is less than 0.5 μm, the anti-blocking effect will be low, and if it exceeds 5 μm, the film surface will become rough, which is not preferable.

Conventionally, aluminum silicate has been studied as an anti-blocking agent, but compared to silica, magnesium silicate, calcium sulfate, calcium metasilicate, etc.
This is because the anti-blocking effect is poor and the hue of the film deteriorates.

It was said that it was difficult to use practically (Special Publication Publication No. 52-318
No. 96, JP-A-57-25918, JP-A-Sho. 5
5-147537) However, according to the present invention, if hydrated aluminum silicate and calcined aluminum silicate are used together, a sufficient blocking prevention effect can be obtained, and the hue of the film will not deteriorate, making it practical. The unexpected result is that it provides a polyethylene film with excellent antiblocking effect without any defects.

In the present invention, the amount of the hydrous aluminum silicate and calcined aluminum silicate is such that the total amount thereof is 0.01 to 1% by weight based on the weight of the polyethylene polymer;
It is preferably selected to be in the range of 0.03 to 0.6% by weight. If this amount is less than 0.01% by weight, the anti-blocking effect will be low, and if it exceeds 1% by weight, the appearance and optical properties of the film will deteriorate. In addition, the preferred blending amount varies depending on the type of polyethylene used; for example, when using low density polyethylene, it is 0.06 to 3% by weight.
, 0.0 when using ethylene-vinyl acetate copolymer
It is preferable to select it within the range of 5 to 0.5% by weight.

As is clear from this amount, in the present invention, the range of addition amount of aluminum silicate as a filler used for purposes such as an extender and a reinforcing agent is clearly different.

Furthermore, in the present invention, the ratio of the hydrated aluminum silicate to the calcined aluminum silicate is 10:9 by weight.
0 to 95:5, preferably so:so to 90:
It needs to be in the range of 10. If the proportion of hydrated aluminum silicate is less than the above range, the anti-blocking effect will be excellent, but the transparency of the film will decrease, while if it is more than the above range, the transparency of the film will be excellent, but
Blocking prevention effect decreases.

In the present invention, predetermined amounts of the hydrated aluminum silicate and calcined aluminum silicate are added to an ethylene polymer base material and kneaded by, for example, a direct addition method, a masterbatch method, a slurry method, etc. By forming the composition into a film, a desired anti-blocking film can be obtained. At this time, a lubricant is usually used in combination as another additive.

Effects of the Invention The anti-blocking film of the present invention has improved the drawbacks of the conventional anti-blocking film that uses silica powder as an anti-blocking agent, and has excellent anti-blocking properties (=, good It has excellent characteristics such as excellent transparency and hue, and very little clouding due to friction.

Example Next, the present invention will be explained in more detail with reference to Examples.

In addition, the film was evaluated by the following method.

Hue: The hue was observed when the films were piled up.0 White spots: The ease with which white spots formed when the films were slid together in a shaker was observed.

Transparency: Haze Measured according to ASTM D-1003 Glossiness Measured according to ASTM D-2457 Transparency Parallel transmission, standard value 10. Comparative value blocking for DO: Measured according to ASTM D-1893 (
A low value results in less blocking, which is preferable in practice. ) Examples 1 to 5, Comparative Examples 1 to 5 As polyethylene, density 0.925 g/C113,
Melt index 3. This (
= A composition obtained by blending a predetermined amount of an anti-blocking agent as shown in Table 1 and further blending 0.1% by weight of erucic acid amide as a lubricant is pelletized, and the pellet is molded using an inflation molding machine. The film was formed using a Modern Machinery 50m inflation molding machine with a die diameter of 100φ.
The molding temperature was 160°C and the blow ratio was 1.5.

The evaluation results of the obtained films are shown in Table 2.

It is clear from Table 2 that by using both components (A) and (B) in combination, a film excellent in both anti-blocking effect and transparency can be obtained.

Although the transparency of the film is excellent when using component (A) alone,
The anti-blocking effect is insufficient. On the other hand, when component (B) is used alone, although the anti-blocking effect is excellent, the transparency of the film is insufficient.

Calcium carbonate produces less cloudiness and less decreases in transparency, but has a low anti-blocking effect.

Zeolite, an aluminum silicate obtained from natural fluoritic tuff, stains the film and significantly reduces its commercial value.

Example 6, Comparative Example 6 As a resin component, an ethylene-vinyl acetate copolymer with a melt index of 2.89710 and a vinyl acetate unit content of 6 weight units was used. The results of film evaluation in the same manner as in Example 1, except that 0.06% by weight of calcined kaolin with an average particle size of 1.4 μm were blended as component (B), The weight percentages are shown in Table 3 together with Comparative Example 6 in which the weight percentages were blended.

Table 3

Claims (1)

[Scope of Claims] 1. For a resin film selected from medium-low density polyethylene, an ethylene-based copolymer mainly composed of ethylene, and a mixture thereof, (A) a water-containing film having an average particle size of 0.1 to 2 μm; A mixture consisting of aluminum silicate and (B) calcined aluminum silicate with an average particle size of 0.5 to 5 μm, the weight ratio of (A) and (B) being in the range of 10:90 to 95:5, A blocking-resistant polyethylene resin film characterized in that it is blended in a proportion of 0.01 to 1% by weight based on the weight of the resin.