JPS61106645A - Plastic film silkish to touch - Google Patents

Abstract

PURPOSE:To provide the titled film whose surface is dull and which is flexible and has excellent resistance to cracking and impact, by molding a mixture of an ethylene/vinyl acetate copolymer and PE into a film. CONSTITUTION:Not more than 50pts.wt. PE having an MI of 0.04-2.0 and additives such as weathering stabilizer, antioxidant, antistatic agent, colorant, etc. are blended with 100pts.wt. mixture obtd. by mixing as ethylene/vinyl acetate copolymer (A) having a vinyl acetate content of 24-34wt% and an MI of 4-40g/10min with PE (B) having an MI of 0.04-2.0g/10min in such a proportion that the mixture has a vinyl acetate content of 12-22wt% and the MI ratio of A to B in the mixture is in the range of 10-100. The resulting compsn. is molded into a film of 100mu or below in thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plastic film having a silky feel. More specifically, the present invention relates to a polyethylene-based plastic film that has no surface gloss, is flexible, and has a silk-like feel.

[Conventional technology]

Polyethylene, especially low-density polyethylene, is easy to form into a film from raw material pellets, and the formed film is relatively versatile in terms of physical properties such as transparency, strength, moisture resistance, gas permeability, and chemical resistance. For these reasons, it is used in large quantities, especially in the packaging film field.

On the other hand, as polyethylene films have become more widely used and their applications have diversified, films that retain many of the physical properties of polyethylene, while others exhibit certain properties that are opposite to those unique to polyethylene. There are also fields of application that require this. In other words, most conventional polyethylene films have a smooth surface, reflective gloss, and high bending rigidity, giving them a hard feel. In order to increase the product value of packaged products and attract consumers' desire to purchase, there is a demand for films with properties that are opposite to those of conventional films, specifically, films that have no surface reflection gloss, are soft and pliable, and are flexible. It is becoming more and more common.

A film with such a unique feel? Manufacturing can be done using existing molding technology or raw resin.
ri□□-7°, eh.

[Means for Solving the Problems] In search of a method for solving the problems, the present inventors have
As a result, by using a mixture of a specific ethylene-vinyl acetate copolymer and polyethylene as a whole film raw material resin and molding it into a film, a plastic with no surface reflection gloss and a supple, silk-like feel was created. Succeeded in getting film la.

Films formed from mixtures of ethylene-vinyl acetate copolymer and polyethylene have been known for a long time, and are described in Japanese Patent Publication No. 40-24913, and they have excellent crack resistance and impact resistance. Therefore, the purpose of the present invention is to obtain a film having an excellent quality. Therefore, the purpose of the present invention is to obtain a film having an excellent quality. It was achieved.

[Means for Solving the Problem] and [Operation] Accordingly, the present invention relates to a plastic film having a silk cloth-like texture, which has a vinyl acetate content of 24 to 34% by weight and an MI of 4 to 40. Consisting of a mixture of ethylene-vinyl acetate copolymer (A) and polyethylene (B) with an MI of 0.04 to λ0, the vinyl acetate content is 12 to 22% by weight, and the M1 ratio of recovered content/component (B) is 10. The mixture is formed into a film shape.

The ethylene-vinyl acetate copolymer used as component (A) has a vinyl acetate content of 24 to 34% by weight,
Preferably 26 to 32 weight i-%, MY (melt index, Li/10 min; ASTM D-1238-
62T) is 4 to 40, preferably '6 to 30. If the vinyl acetate content or MI value in the copolymer is lower than this, the desired silky feel cannot be obtained, and if the vinyl acetate content is higher than this, the moldability and blocking properties of the film will be affected. undesirable,
Furthermore, if the MI is larger than this, fish eyes will occur and problems with film breakage during film forming will increase.

Further, as the polyethylene used as component (B), the following are used, among which the most preferred is (1), and the second most preferred is (3).

(1) Similar to the ethylene-vinyl acetate copolymer, in the presence of a free radical generator under high temperature and high pressure conditions, a comonomer containing ethylene alone or in a small amount (about 3 mol% or less), e.g. So-called high-pressure low-density polyethylene obtained by bulk polymerization with vinyl acetate, acrylic acid, methacrylic acid, or esters thereof (2) A transition metal compound of groups 1 to 2 of the periodic table and 1 to 2
The Ziegler method using a complex catalyst formed from a group of organometallic compounds, the Phillips method using a chromium oxide catalyst supported on alumina or silica-alumina, or the standard method using a molybdenum oxide catalyst supported on alumina, etc. or produced in the gas phase,
So-called medium-low pressure high-density to medium-density polyethylene (3) Ethylene, propylene, butene-1, pentene-1,4-methylpentene produced in the liquid phase or gas phase using the catalyst system in (2) above. -1, octene-1 or a mixture thereof, so-called linear low-density polyethylene These polyethylenes have an Mf% of 0.04 to 2
．． It is necessary that it be within a range of 0; if a value outside this range is used, a film with the feel of a silk dog will not be obtained.

A mixture consisting of these components (AJ component and CB) is
They are mixed and used so that the vinyl acetate content is 12 to 22% by weight and the M el of ((conversion) component/(B) component) is within the range of 10 to 100.

If the vinyl acetate content is lower than this, the desired 1-layer film will not be able to be broken, and if the vinyl acetate content is higher than this, blocking will be significant and the stiffness will be insufficient, so it is not suitable for use as a packaging film. K becomes lacking in aptitude.

Regarding M.el., if it is smaller than this, it will not be possible to obtain a film with the desired feel; on the other hand, if it is larger than this, the state of dispersion between the various components of the mixture will be poor, causing fish eyes on the film. :1 ・'1 This causes problems with film breakage during film molding.

Figure 1 shows an ethylene-vinyl acetate copolymer (A) with a vinyl acetate content of 24 to 34% by weight and 1 iOi containing vinyl acetate.
It is a one-sided logarithmic graph showing the relationship between the vinyl acetate content in the warm mixture of f% polyethylene (B) and MI, and is similar to 5
When q-structured polymers that are compatible with each other are mixed, the mixing ratio and MI are approximately straight fiIA on the one-sided logarithmic graph.
Applying the empirical rule that there is a relationship, the range of a mixture containing vinyl acetate from 12 to 22% by weight is a-b-Q-
From points a and C of d, the MI range of the mixture is approximately 0.
．． Therefore, in the present invention, the M1 value of component (A)/(B) component is determined as a value of 4 to 14.
A mixture having an L of 10 to 100 will be used.

When the resulting film is used for automatic filling packaging, etc., it may be required to have more elasticity than silk cloth-like feel, so MI other than that specified in component (B) may be used.
Various polyethylene (C) k, mixture 100
It can be added in a proportion of up to about 50 parts by weight.

In addition to the above-mentioned components, other components may be added if necessary, such as antioxidants, weather stabilizers, antistatic agents, colorants, etc.

The mixture is prepared by tri-blending or melt-blending the components, either simultaneously or sequentially. In the case of a triblend, the components are mixed in a molding machine during the melt-plasticization stage. In addition, in the case of melt blending, it is sufficient to melt and mix using various extruders such as a single-screw extruder and twin-screw extruder, various mixers such as a Banbury mixer, rolls, and Nigu. There is no particular restriction on the order.

Forming into a film can be carried out by any method such as c, inflation method, or casting method, and there is no particular restriction on the thickness of the formed film, but the silk cloth-like feel is about 100 μm or less, preferably about 70 μm or less. It is easy to obtain a film with a thickness of .

〔Effect of the invention〕

The film according to the present invention has no surface reflection gloss and has a soft and supple silk-like feel.

The lack of surface reflection gloss is caused by the fine irregularities of the film surface and internal opacity. The fine unevenness is almost uniquely determined by the mixing state of both components in the mixture, and if the unevenness is too large or too small, a silk cloth-like feel cannot be obtained. Further, the internal opacity is influenced by the difference in the optical refractive index of each component forming the mixture and the mixing and dispersion state between the components. Furthermore, the soft and supple feel is mainly influenced by the vinyl acetate content in the mixture, but is also influenced by the mixing ratio and dispersion state of the mixture. These various factors can be adjusted to provide a satisfactory result by selecting the conditions defined in the present invention, and a film having a silk-like feel can be obtained.

〔Example〕

Next, the present invention will be explained with reference to examples.

Example 1 High pressure low density polyethylene (density 0.9189/Ctd
, MI0.23) (weight, same hereinafter) and ethylene-vinyl acetate copolymer (vinyl acetate content 28% by weight,
62 parts of MI15, density 0.95 g/ca) were melt blended at 190° C. and 60 rpm using a 401Ell diameter extruder equipped with a Dalmage type screw.

This mixture had a vinyl acetate content of 18 f1%, an MI of 2.8, and a density of 0.9389A.

Using this mixture, the polymer was melted using a 40 diameter metallurgical extruder at a temperature of 160°C and a blowing ratio of 1.5 to a thickness of 0.0411111 mm.
A lane con film was formed.

Comparative Example 1 Low density polyethylene (density 0.921 g shoulder, MI2.
8), a blown film was molded in the same manner as in Example 1.

Comparative Example 2 Ethylene-vinyl acetate copolymer (vinyl acetate content 18
% by weight, using anus 1), the SO, S throat bent groove pattern was fully embossed, minimum cross-sectional thickness 0.05)',)
′″0′6′”′&″″″JIg L, *・Measurements of physical properties were performed on the films obtained in the above Examples and Comparative Examples.The obtained results are shown in the following table. 1
is shown.

Table 1 Example Kenpo j1 Comparative example 1 Comparative example 2
Surface reflection gloss (support) 0.6 64
(30) Transparency (%) <1
54 (25) Brightness
Large Small Small Modulus of Elasticity (g)
0.31 1.72 - Blockin Endothelium (9/2fi) 0 0.1
1.0 Kneading sound No Yes
Feel Soft Hard Hard as a whole (Hard parts and Yui Yiru decorative pasting) Note 1) Values in parentheses are reference values as they depend on the embossed pattern.Note 2) Elastic modulus is the handle - 〇 - meter From the above results obtained by the method, the film according to the present invention, which has a silk cloth-like feel, is opaque, has little surface reflection gloss, has a white shine, has low elasticity, is flexible, does not make any kneading noise, and has a good blocking effect. It turns out that there are almost no Moreover,
The film strength thereof was almost the same as that of the low density polyethylene film of Comparative Example 1.

Examples 2 to 4, Comparative Examples 3 to 4 A mixture was prepared in the same manner as in Example 1 using the polyethylene, ethylene-vinyl acetate copolymer (vinyl acetate content: 28% by weight) shown in Table 2, and gold. Molding of blown film was carried out.

Evaluations of the obtained films are also listed in Table 2.

Table 2 MI 0.23 0.38 0.10 0.1
0 5.5 Density (9/cd> 0.918 0.9
19 0.918 0.918 0.917 Blend amount (
Department) 38 46 38 38
38 [Vinyl acetate copolymer] MI 15 25 6 25
6 Blend amount 1 part) 62 54
62 62 62 [Mixture] MI 3.0 4.0 1.2 λ
05.8 Vinyl acetate content (%) 18 15
18 18 18 Fishery
OOOx x (Evaluation method) Silk cloth-like feel = O enough, × Not at all
O Not at all, × Very much film processability 20 Good, ×
Fish eye with a lot of fillet 20 None, × Very Yes Example 5 High pressure process low density polyethylene (Dense! 0.9199/ad
.

MIO, 23) Using 40 parts and 60 g of the ethylene-vinyl acetate copolymer of Example 1, in the same manner as in Example 1,
Vinyl acetate content 16.8ffiiL%, wX 3.3
, a density of 0.93897 cd was prepared.

Add 80 parts of this mixture to low-pressure low-density polyethylene (density & 0%
．． 9239A, MI11) (blended and mixed using a 5011III diameter Metallinges screw extruder under the conditions of a polymer melt temperature of 150°C, a withdrawal speed of 1!!MFI/min, and a blow ratio of 1.5). A blown film with a thickness of 0.02 .mu.m was formed.

The obtained film had a silk-like feel, was pliable and soft, and had a tensile modulus sufficient for use as a film for automatic filling and packaging.

Example 6 Low pressure method low @ anti-polyethylene (density 0.9209/am
.

yx O, 5) and 60 parts of the ethylene-vinyl acetate copolymer of Example 1 were triblended to give a vinyl acetate content of 1-16.81% by weight, MI 4.3, vK O
,938V! A triblend of I was prepared.

Using this triblend product I, a blown film with a thickness of 0.04111111 was formed using a 3Qmar diameter metallingue screw extruder under the following conditions: a polymer melt temperature of 147°C, a take-up speed of K of 33 m7, and a blow ratio of Z of 3517. .

The obtained film had a silk cloth-like feel and was supple and soft. However, compared to the film obtained in Example 1, it was a little stiffer.

Example 7 '1 High density polyethylene (density 0.9569 shoulder,
MI0.05)□゛・(40 parts and 60 parts of the ethylene-vinyl acetate copolymer of Example 1
A triblend material having a vinyl acetate content of 16.8% by weight, an MI of 1.9, and a density of 0.9529y- was prepared by triblending part and all of the sample.

Using this tri-blend product i, 3Q+m diameter metallingue screw extruder', the polymer melt temperature IJj was 151°C.
The film was formed into a blown film with a thickness of 0.04 ffl+ under the conditions of a take-up speed of 3.3 m7 minutes and a blow ratio of 2.35.The resulting film had a silk cloth-like feel. However, compared to the films obtained in Examples 1 and 5,
My lower back was stiff.

[Brief explanation of drawings]

FIG. 1 is a one-sided logarithmic graph showing the relationship between the vinyl acetate content and MI of the mixture resin raw material used for film formation of the present invention.

Claims (1)

[Claims] 1. Vinyl acetate content 24-34% by weight, MI4-40
ethylene-vinyl acetate copolymer (A) and MI0.
Consisting of a mixture of polyethylene (B) of 04 to 2.0,
A plastic film having a silk cloth-like feel formed by forming a mixture containing vinyl acetate from 12 to 22% by weight and having an MI ratio of component (A)/component (B) from 10 to 100. . 2. The plastic film according to claim 1, wherein the polyethylene (B) is low density polyethylene. 3. Vinyl acetate content 24-34% by weight, MI4-40
ethylene-vinyl acetate copolymer (A) and MI0.
Consisting of a mixture of polyethylene (B) of 04 to 2.0,
About 50 parts by weight or less per 100 parts by weight of the mixture is added to the mixture in which the vinyl acetate content is 12 to 22% by weight and the MI ratio of component (A)/component (B) is 10 to 100. A plastic film having a silk cloth-like feel, which is further mixed with polyethylene (C) having an MI outside the range of 0.04 to 2.0 and formed into a film. 4. The plastic film according to claim 3, wherein the polyethylene (B) is low density polyethylene.