JPH0778128B2 - Matte film - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a matte film.

[0002]

2. Description of the Related Art Saponified ethylene-vinyl acetate copolymer (hereinafter referred to as EVOH) is excellent in chemical resistance, stain resistance, and plasticizer bleed prevention, and is a film on the surface of interior materials such as PVC wallpaper and PVC leather. It is pasted and used. However, the EVOH film has a high glossiness, and for applications such as wallpaper and PVC leather, which are required to have a matte finish, they are matted by thermocompression bonding with a matte roll. However, in the case where sufficient pressure is not applied, there is a problem that the gloss of the EVOH surface cannot be erased, and matted EVOH is required. Conventionally known methods for delustering a film include (1) a sandblast method, (2) a surface treatment method with a chemical agent, and (3) a method of blending a powdered inorganic substance. However, these methods have drawbacks such as high cost and poor film forming property. In particular, the method of blending the powdered inorganic substance of (3) has a drawback that matting is not sufficient, and if the blending ratio of the powdered inorganic substance is increased in order to achieve sufficient matting, a film cannot be formed with holes. Have

Further, a technique of a resin composition obtained by blending EVOH and a carboxylic acid-modified olefin resin is described in JP-A-55-131033, but no technique of a matte film is disclosed. Further, if these techniques are used as they are, a matte film cannot be easily obtained. In addition, E in Japanese Utility Model No. 61-2652
The technique of a film in which VOH and a carboxylic acid-modified olefin resin are blended is described, but the blend composition is different from that of the present invention, and it is not a technique of a matte film.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a film having improved conventional moldability and having a sufficient matte effect.

[0005]

The present invention provides (A) EVO
It is a matte film having a glossiness of 60% or less in which (B) a carboxylic acid-modified polyethylene resin is blended with H.

The EVOH of the present invention is a saponified ethylene-vinyl acetate copolymer having an ethylene content of 20 to 60 mol%, preferably 25 to 55 mol%, and a saponification degree of the vinyl acetate component of the copolymer. 90% or more. If the ethylene content is less than 20 mol%, the film's performance such as water resistance and hot water resistance deteriorates. When the ethylene content exceeds 60 mol% or the saponification degree is less than 90%, when the obtained film is laminated on polyvinyl chloride containing a plasticizer and used as a wallpaper, the plasticizer is prevented from bleeding. Performance, etc. will decrease. It is free to use comonomer components other than ethylene and vinyl acetate components in this EVOH within a range that does not impair the object of the present invention.

Next, the carboxylic acid-modified polyethylene resin used in the present invention is a polyethylene resin to which an α, β unsaturated carboxylic acid or the carboxylic acid anhydride is added or grafted. The content of α, β unsaturated carboxylic acid or carboxylic anhydride (addition amount or graft amount)
Is 0.0005 to 0.5 mol% and preferably 0.001 to
It is 0.4 mol%. EV less than 0.0005 mol%
When blended with OH, the dispersibility deteriorates, and the matte effect of the film is poor. On the other hand, when it exceeds 0.5 mol%,
The thickening during the blending operation is large and the film forming property becomes poor.
The blending ratio of (A) EVOH and (B) carboxylic acid-modified polyethylene resin is (A) 95 to 50% by weight, and (B) 5 to
A 50 wt% blend develops the effect of the present invention. More preferable ranges are 92 to 55% by weight of (A) and 8 to 45% by weight of (B). If the component (B) is less than 5% by weight, the glossiness is not satisfied. On the other hand, if it exceeds 50% by weight, (A) does not exist in the form of sea and (B) does not exist in the form of island in the film, and EV
The original performance of OH deteriorates, and there are drawbacks such as holes in the film.

Next, in the present invention, (A) EVOH,
(B) Melt index of carboxylic acid-modified polyethylene resin (measured at 190 ° C. under a load of 2160 g:
2 if the melting point is around 190 ° C or exceeds 190 ° C
Measured at a plurality of temperatures above the melting point under a load of 160 g, and plotted on a semilogarithmic graph with the reciprocal of absolute temperature plotted as the horizontal axis and the melt index as the vertical axis, and the value extruded to 190 ° C. is M
When IA and MIB are used, it is preferable to select them so as to satisfy the following expressions (1) to (3).

0.1 ≦ MIA ≦ 15 (1) 0.01 ≦ MIB ≦ 10 (2) 1.5 ≦ MIA / MIB ≦ 100 ... (3) It is preferably within the range of the following expressions (4) to (6). 0.1 ≦ MIA ≦ 15 (4) 0.01 ≦ MIB ≦ 7.5 (5) 2 ≦ MIA / MIB ≦ 80 (6) Especially, the optimum range of MIA / MIB is 3 ≦ MIA / MIB ≦ 80.

When the above formulas (1) to (3) are satisfied, a desired desired matte film can be obtained. The carboxylic acid component of the carboxylic acid-modified polyethylene resin used in the present invention is an α, β-unsaturated carboxylic acid having 3 to 10 carbon atoms or the carboxylic acid anhydride, such as acrylic acid, methacrylic acid, ethacrylic acid, and maleic acid. Examples thereof include acids, itaconic acid, maleic anhydride, and itaconic anhydride. Of these, maleic anhydride and itaconic anhydride are preferable. The polyethylene resin includes high density polyethylene, low density polyethylene, and linear low density polyethylene.

The method for producing the carboxylic acid-modified polyethylene resin used in the present invention is not particularly limited, but a method of graft-polymerizing an α, β unsaturated carboxylic acid or the carboxylic acid anhydride onto polyethylene is preferred. EV in the present invention
As a method for blending OH and a carboxylic acid-modified polyethylene resin, there is a method such as melt blending using a single-screw or twin-screw extruder. The blend is preferably pelletized once and then formed into a film. When the film is formed as it is without pelletizing, the dispersion of the blended product may be poor, and the desired matte film may not be obtained. During this blending, other additives may be added within the range not impairing the object of the present invention. Examples of such additives include antioxidants, ultraviolet absorbers, lubricants, and the like.

The film of the present invention can be obtained by melt-forming the above blend by a usual T-die method or an inflation method. When obtaining a film by the T-die method, for example, rapid cooling of the extruded film is an important condition. When gradually cooled, the glossiness becomes large and the matte film becomes unsatisfactory. Here, the term "quench cooling" means that the die air gap is made as small as possible, and the extruded film is cooled by an air slit, an air chamber or electrostatic application, for example, 60 ° C or lower, preferably 6 ° C.
It is to cool rapidly by bringing it into close contact with a cast roll adjusted to 0 to 30 ° C.

Next, in the film of the present invention, (A) EVOH
It is important that the (B) carboxylic acid-modified polyethylene resin exists in the form of islands and the island-like form of the (B) carboxylic acid-modified polyethylene resin, and this is considered to contribute to matting. If (A) does not have a sea-like shape and (B) does not have an island-like shape, the original surface characteristics of EVOH are impaired, and there are disadvantages such as holes being formed during film formation. In the present invention, the sea-like (dispersion medium component) and the island-like (dispersion component) means that the dispersion components are dispersed in the form of particles or thin films.
Unlike a laminated film, it is neither continuous on one side nor lumped and penetrates both sides of the film.

The gloss of at least one surface of the film of the present invention is required to be 60% or less, preferably 50% or less, and most preferably 40% or less. Insufficient as a 60% matte film. Here, the glossiness is an average value of values measured at arbitrary 5 points measured at an angle of 75 degrees with a Murakami glossmeter.

Furthermore, the unevenness of the film of the present invention is 3
It is necessary to be ~ 15μ, preferably 4 ~ 12μ
Is. If it is 3 μm or less, it is insufficient as a matte film, and if it exceeds 15 μm, the film tends to have holes.
The method for evaluating the degree of unevenness is as follows.

A film measuring 20 cm × 20 cm is sampled, and the thickness is measured at appropriate intervals at nine places, and a thickness measuring device (Sag
Inomiya's DIAL INDICATOR M
ODERU LCM-0101), and the average value thereof is (L 1). Further, the weight of the sampling film is measured, and the density of the sampling film is toluene, and the density is measured by a buoyancy method using a carbon tetrachloride mixed solvent. The value obtained by calculating the thickness of the film from this weight and density is defined as (L 2). When the unevenness degree is ΔL, it is expressed by the following equation. ΔL = (L 1)-(L 2)

The thickness of the film of the present invention is not particularly limited, but is preferably 10 to 50 μm. If it exceeds 50 μ, it is disadvantageous for the rapid cooling operation during film formation. By thus laminating the film thus obtained on the surface of wallpaper, interior materials such as vinyl chloride leather, especially on the surface of wallpaper made of polyvinyl chloride containing a plasticizer, while preventing bleeding of the plasticizer, It is possible to give a high-class feeling with the loss of gloss.

[0018]

The present invention will be further described with reference to the following examples.
Unless otherwise specified,% in the examples means% by weight.

Example 1, Comparative Example 1 Ethylene content 38 mol%, saponification degree 99.4 mol%,
92% EVOH pellets with a melt index of 3.8 g / 10 minutes (under conditions of 190 ° C. and a load of 2160 g), maleic anhydride modified (modification rate 0.09 mol%), melt index 1.0 g / 10 minutes (190 ° C., Load 2160g
8% of high-density polyethylene resin pellets (under conditions) were blended and pelletized by a twin-screw extruder. The blended pellets were extruded from a T-die extruder onto a cast roll adjusted to 40 ° C., and at the same time, air was blown onto the film surface on the side opposite to the cast roll side from an air slit to rapidly cool the film to form a film having a thickness of 30 μm. I got a film. The glossiness of this film is 42%, and the unevenness is 4.
It was 1μ. When the cross section of the film of Example 1 was dyed with an iodine solution which only EVOH was dyed and observed under a microscope, it was confirmed that the carboxylic acid-modified polyethylene resin was present in the sea of EVOH in an island shape. TD of this film
A schematic view of the cross section (width direction) is shown in FIG. 1 in MD (machine direction).
A schematic view of the cross section is shown in FIG.

As Comparative Example 1, ethylene content 38 mol%, saponification degree 99.4 mol%, melt index 3.
8 g / 10 minutes (190 ° C., load 2160 g),
97% EVOH pellets and maleic anhydride modified (modification rate 0.09 mol%), melt index 1.0 g / 10
Minutes (190 ° C., under a load of 2160 g) of 3% high-density polyethylene was blended and pelletized with a twin-screw extruder. This blended pellet was formed into a film under the same conditions as in Example 1 to obtain a 28 μm film. The glossiness of this film was 75% and the roughness was 2.2μ.

Example 2, Comparative Example 2 Ethylene content 44 mol%, saponification degree 99.4 mol%,
55% EVOH pellets with a melt index of 5.0 g / 10 min (190 ° C., load of 2160 g), itaconic acid modification (modification rate 0.005 mol%), melt index of 0.2 g / 10 min (190 ° C., load) 45% of low density polyethylene (under 2160 g conditions) was blended and pelletized in a single screw extruder. This blended pellet was formed into a film under the same conditions as in Example 1, and 25 μm was formed.
I got a film of. The glossiness of this film was 18%, and the unevenness was 7.5μ. When the cross section of this film was observed with a microscope in the same manner as in Example 1, it was confirmed that the carboxylic acid-modified polyethylene resin existed like islands in the EVOH sea.

As Comparative Example 2, ethylene content 44 mol%, saponification degree 99.4 mol%, melt index 5.
0 g / 10 min (190 ° C., load 2160 g)
45% EVOH pellets, modified with itaconic acid (modification rate 0.005 mol%), melt index 0.2 g / 1
55% of low-density polyethylene at 0 minutes (190 ° C., under a load of 2160 g) was blended by a single-screw extruder and pelletized. This blended pellet was formed into a film under the same conditions as in Example 1 to obtain a 25 μm film.
The film had holes and was defective. When the cross section of this film was observed with a microscope in the same manner as in Example 1, it was confirmed that the polyethylene carboxylate resin was not present in the EVOH sea in the form of islands.

Example 3, Control Example 3 Ethylene content 52 mol%, Saponification degree 95.5 mol%,
75% EVOH pellets with a melt index of 8.7 g / 10 min (190 ° C., load 2160 g) and maleic acid modification (modification rate 0.01 mol%), melt index 0.2 g / 10 min (190 ° C., load 2160 g) Films were formed in the same manner as in Example 1 except that 25% of high-density polyethylene (under conditions) was used, and a film having a thickness of 45 μm was obtained. The gloss of this film is 28%, and the unevenness is 6.7μ.
Met. When the cross section of this film was observed with a microscope in the same manner as in Example 1, it was confirmed that the carboxylic acid-modified polyethylene resin existed like islands in the EVOH sea.

As Comparative Example 3, ethylene content 44 mol%, saponification degree 99.4 mol%, melt index 5.
0 g / 10 min (190 ° C., load 2160 g)
75% EVOH pellets and 0.2 melt index
A film having a thickness of 45 μm was obtained by forming a film on the film in the same manner as in Example 1 except that 25% of high-density polyethylene of g / 10 min (190 ° C., under a load of 2160 g) was used. This film had a streak pattern in the machine direction and had a poor appearance. The glossiness was 85% and the unevenness was 3.1μ.
Further, when the cross section of this film was observed with a microscope in the same manner as in Example 1, a portion where polyethylene existed in a layer in the sea of EVOH and a portion where the polyethylene resin was in a large lump were observed.

Example 4, Control Example 4 Ethylene content 27.5%, saponification degree 99.5 mol%,
75% EVOH pellets with melt index 1.3 g / 10 min (190 ° C., load 2160 g), maleic acid modified (modification rate 0.01 mol%), melt index 0.4 g / 10 min (190 ° C., A film having a thickness of 30 μm was obtained by forming a film on the film in the same manner as in Example 1 except that 25% of low-density polyethylene under a load of 2160 g was used. The glossiness of this film was 22%. The irregularity was 10.8μ.

As Comparative Example 4, the ethylene content was 27.5.
Mol%, saponification degree 99.4 mol%, melt index 1.3 g / 10 minutes (190 ° C., load 2160 g)
75% EVOH pellets and maleic acid modified (modification rate 0.01 mol%) melt index 0.4 g / 10
A film having a thickness of 30μ was obtained by forming a film on the film in the same manner as in Example 1 except that 25% of polypropylene (190 ° C., load: 2160 g) was used. This film had a streak pattern in the machine direction and had a poor appearance. The glossiness was 81.4%.

Example 5 Ethylene content 31.5%, saponification degree 99.5 mol%,
75% EVOH pellets with a melt index of 1.0 g / 10 minutes (under a condition of 190 ° C. and a load of 2160 g) and maleic acid modification (modification rate 0.01 mol%), melt index 0.4 g / 10 minutes (190 ° C., A film having a thickness of 32 μm was obtained by forming a film on the film in the same manner as in Example 1 except that 25% of linear low density polyethylene under a load of 2160 g was used.

Control Example 5 A film was formed on a film in the same manner as in Example 5 except that a linear low density polyethylene modified with maleic acid (modification rate 0.01 mol%) and a melt index of 2.0 g / 10 min was used.
A 3μ film was obtained.

Example 6 A film was formed on a film in the same manner as in Example 5 except that linear low density polyethylene modified with maleic acid (modification rate 0.01 mol%) and a melt index of 0.1 g / 10 min was used.
A 3μ film was obtained.

Example 7 Ethylene content 31.3%, Saponification degree 99.6 mol%,
A film having a thickness of 30 μ was obtained by forming a film on the film in the same manner as in Example 6 except that EVOH pellets having a melt index of 7.5 g / 10 min were used.

Control Example 6 Ethylene content 31.5%, Saponification degree 99.5 mol%,
75% EVOH pellets with a melt index of 12.0 g / 10 minutes, maleic acid modification (modification rate 0.01 mol%), and 25% linear low density polyethylene with a melt index of 0.1 g / 10 minutes were used. A film was formed on the film in the same manner as in Example 1 to obtain a 30 μm film. Glossiness of the films obtained in Examples 5-7 and Control Examples 5-6,
The degree of unevenness is shown in Table 1.

[0032]

[Table 1]

Comparative Example 7 The blended pellets used in Example 1 were extruded from a T-die extruder onto a drum adjusted to 80 ° C. and gradually cooled to form a film, thereby obtaining a 30 μ film. The glossiness of this film was 65% and the roughness was 2.8μ.

Comparative Example 8 In Comparative Example 7, maleic anhydride modified high density polyethylene resin was replaced with maleic anhydride modified (modification rate 0.1 mol%), melt index 6 g / 10 min ethylene (75 wt%)-acryl. A 30 μ film was obtained under the same conditions as in Comparative Example 7 except that the acid ethyl ester (25% by weight) copolymer was used. The glossiness of this film is 6
8% and the unevenness was 2.7μ. By laminating the matte films obtained in the above Examples 1 to 7 on the surface of a soft polyvinyl chloride wallpaper containing a plasticizer, a wallpaper without plasticizer bleeding and having a dull gloss is provided. I was able to get

[0035]

INDUSTRIAL APPLICABILITY According to the present invention, a film having an excellent matting property can be obtained, the EVOH property can be fully utilized, and the film can be used for applications requiring matting properties.

[Brief description of drawings]

FIG. 1 is a schematic view of a TD cross section of the film obtained in Example 1.

FIG. 2 is a schematic view of an MD cross section.

[Explanation of symbols]

 1 ... Carboxylic acid modified polyethylene 2 ... EVOH

Claims (1)

[Claims] 1. An ethylene-vinyl acetate copolymer saponification product (A) having an ethylene content of 20 to 60 mol% and a saponification degree of 90% or more (A) of 95 to 50% by weight, and a carboxylic acid-modified polyethylene resin (B) of 5 to 50% by weight. %, The (A) is present in the shape of a sea, the (B) is present in the shape of an island, and the surface glossiness of at least one surface is 60% or less.