JP2688893B2 - the film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic film used as a packaging bag, a packaging film and the like, and more particularly to a film having a pattern on its surface.

[0002]

2. Description of the Related Art Thermoplastics such as polyethylene and polypropylene are used as materials for packaging bags such as shopping bags and films for food packaging. For example, a packaging bag is formed by cutting a film formed into a tube shape by inflation molding into an appropriate length and sealing one end by heat welding or the like.

[0003]

These plastic bags are colored in various colors. However, according to the coloring method using a powder or liquid colorant or a masterbatch, the entire surface of the film is the same. There was no method other than printing for applying the pattern, because the pattern was not developed but only colored.

Accordingly, it is an object of the present invention to provide a plastic film having a pattern on its surface.

[0005]

In order to achieve the above object, the invention according to claim 1 is such that the base material which is a thermoplastic is not compatible with the thermoplastic and the thermoplastic is Was mixed with fibrous materials of different colors, and the mixture was formed into a tube by inflation molding to form a film.

Thermoplastics as the basic material are
Typical examples are polyolefins such as polyethylene and polypropylene, but other thermoplastics such as polydiolefins, polyethers, polyamides and thermoplastic polyurethane elastomers are also included as long as they can be inflation-molded. Incompatible fibrous substances are, for example, when the basic material is polyethylene or polypropylene, for example, fibrous rayon or polyester, which are insoluble in the solvent of the thermoplastic material as the basic material and do not mix with each other. Is. The fibrous material has a color different from that of the thermoplastic which is the basic material, and may be dyed with a dye or the like. When the thermoplastic material, which is the basic material, is transparent, the fibrous material is opaque, or if it is translucent but has a hue or saturation, different colors are used. Thermoplastics, which is the basic material, can usually be colored in any color with pigments, and a mixture of fibrous materials of different colors is formed into a tube shape by inflation molding, resulting in a fibrous pattern on the surface. A coated film can be obtained.

The film according to the invention of claim 2 is
The film according to claim 1 and a thermoplastic resin film having a color different from that of the fibrous material mixed with the film and containing no fibrous material constitute two or more layers. Become.

For example, a fibrous material such as rayon has a large hygroscopic property, and even if it is a master batch, it absorbs moisture during short-term storage. Therefore, when inflation molding is performed, pinholes are generated due to the phenomenon of moisture absorption. I have something to do. Since the air blown into the melting tube escapes from this pinhole, the tube does not swell to a predetermined size, and thus a product in a predetermined state is not obtained. Therefore, at least one layer of the multi-layer film is made of a thermoplastic resin film in which no fibrous material is mixed to prevent air bleeding and to obtain a good film with no change in tube folding width.

According to the third aspect of the present invention, the film according to the second aspect is configured such that the thermoplastic resin film layer in which the fibrous material is not mixed constitutes the innermost surface.

For example, when a fibrous material such as rayon is dyed with a dye, it may not be suitable as a food packaging film or the like depending on the type of the dye. For example, in the case of toxic dyes, the dyes may migrate to food or other items. Therefore, by forming the innermost surface of the film as a film layer containing no fibrous material, it can be used for packaging foods.

According to the invention described in claim 4, the film according to claim 2 is constituted so that the layer of the thermoplastic film in which the fibrous material is not mixed constitutes the outermost surface.

Since the fibrous material appears on the surface of the thermoplastic resin film having a pattern formed by mixing the fibrous material, the surface smoothness is significantly impaired. For this reason, the surface gloss is deteriorated and the sliding characteristics are deteriorated. Therefore, the outermost surface is a layer of a thermoplastic plastic film in which no fibrous material is mixed, so that smoothness and transparency are improved and gloss is exhibited. Therefore, the layer of the film forming the outermost surface has a low molecular weight and little crystallization,
It is preferably made of a highly transparent thermoplastic.

[0013]

Embodiments of the present invention will be described below.

In each example, (1) resin LLDPE (linear low density polyethylene) 0134H
(Manufactured by Idemitsu Petrochemical Co., Ltd., MFI = 1.0, D = 0.
920, C4 copolymer) LLDPE 0138H (manufactured by Idemitsu Petrochemical Co., Ltd.,
MFI = 1.0, D = 0.920, C8 copolymer) HDPE (high density polyethylene) 640UF (manufactured by Idemitsu Petrochemical Co., Ltd., MFI = 0.04, D = 0.95)
3) Pigment Masterbatch PEX 530919 Whi
te (manufactured by Tokyo Ink Co., Ltd.) Rayon fiber masterbatch EEM-7-1433
(Okay Kasei Co., Ltd.) (2) Molding machine 3-layer inflation molding machine (manufactured by Placo Co.) Extruder L-55BS for inner layer, middle layer, outer layer
(Manufactured by Placo Co., Ltd.) Three-layer die inside die / 200 mmφ clearance 2.0 mm (3) Molding conditions Temperature molding machine C1: 180 ° C. C: 180 ° C3: 180 ° C AD: 180 ° C Die D1: 180 ° C D2: 180 ° C D3: 180 ° C. Discharge rate Inner layer = 35 kg / Hr (35%) Middle layer = 35 kg / Hr (35%) Outer layer = 30 kg / Hr (30%) Molded film specification Width = 420 mm Wall thickness = 100 μm

Example 1 (1) Inner layer = 0138H (90%, weight ratio, the same applies hereinafter) PEX 530919 White (3%) EEM-7-1433 (7%) Middle layer = 0138H (90%) PEX 530919 White (3) %) EEM-7-1433 (7%) Outer layer = 0134H (100%)

(2) When the raw materials having the above-mentioned layer constitution were molded under the above-mentioned molding conditions, a mottled film having a surface gloss of 98% and a green fiber dispersed in milky white was produced.

Example 2 Inner layer = 0138H (97%) PEX 530919 White (3%) Middle layer = 0138H (97%) EEM-7-1433 (3%) Outer layer = 0134H (100%)

(2) When the raw materials of the above layer constitution were molded under the above molding conditions, a mottled film having a surface gloss of 98% and a green fibrous material dispersed in milk white was produced.

Example 3 (1) Inner layer = 0138H (97%) PEX 530919 White (3%) Middle layer = 640UF (97%) EEM-7-1433 (3%) Outer layer = 0134H (100%)

(2) When the raw materials having the above-mentioned layer constitution were molded under the above-mentioned molding conditions, a film having a surface gloss of 98% and a mottled pattern in which green fibrous materials were dispersed in milky white was produced.

Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the above embodiments and can be appropriately modified within the scope of the gist of the present invention.

[0022]

As described above, according to the film of the first aspect of the invention, a film having a fibrous pattern on its surface can be obtained.

According to the film of the second aspect of the present invention, air is not released even though pinholes are generated due to foaming of moisture absorbed by the fibrous material.
It is possible to obtain a film having a constant folding width and thickness.

The film according to the third aspect of the present invention can be used for various purposes such as food packaging, regardless of the toxicity of the dye in the fibrous material.

According to the film of the invention described in claim 4, the smoothness and transparency of the surface of the film is improved, and the gloss is exhibited, so that the commercial value can be enhanced.

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Claims (4)

(57) [Claims] 1. A base material which is a thermoplastic is mixed with a fibrous material which is incompatible with the thermoplastic and has a color different from that of the thermoplastic,
A film obtained by forming the mixture into a tube by inflation molding. 2. The film according to claim 1 and a thermoplastic resin film having a color different from that of the fibrous material mixed with the film and having no fibrous material mixed, have two or more layers. A film made up of layers. 3. The innermost surface is formed by a layer of a thermoplastic resin film in which no fibrous material is mixed.
The film according to 1. 4. A layer of a thermoplastic resin film not mixed with fibrous material constitutes an outermost surface.
The film according to 1.