JPS6116854A - Bag - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to colored laminated film bags.

[Prior art]

Conventionally, colored bags were used because of their strong elasticity.
Single-layer films made of high-density polyethylene mixed with colorants are widely used.

However, the colored film made of high-density polyethylene does not have a glossy surface, so the colored film does not stand out, resulting in a less beautiful appearance.Additionally, it is necessary to mix the coloring agent into the entire film, which requires expensive coloring materials. There was a drawback that the amount used was large and the puncture strength was insufficient.

[Object of the present invention]

The object of the present invention is to find a bag that has excellent gloss, has elasticity, stands out in color, has high puncture strength, and can reduce the amount of coloring agent used.

[Configuration of the present invention]

The structure of the present invention consists of a laminated film coextruded with polyethylene having a density of 0.9401 vCC or more and polyethylene having a density of 0.930 f//CC or less and containing a coloring agent at a higher concentration than the polyethylene, 0.93
This bag is characterized by having a polyethylene layer of 01/CC or less on the outside.

The present invention will be explained in detail below.

Density 0.940Vc used in the laminated film of the present invention
c polyethylene (hereinafter referred to as polyethylene A)
is linear or nearly linear high-density polyethylene (HDP)
). Also, the density is 0.9301g/cc
The following polyethylene (hereinafter referred to as polyethylene B)
is low-density polyethylene (hereinafter referred to as 'LDPE') with long-chain branches produced by a high-pressure process, or linear low-density polyethylene (hereinafter referred to as 'LLDP') with short-chain branches produced by a low-pressure process.
(referred to as E) are used, but from the viewpoint of gloss, LL
DPE is preferred.

Further, the melt index (hereinafter referred to as MI, JIS K6760) of the polyethylenes A and B is preferably 4.1iI710 min or less, and if it exceeds this, film forming becomes difficult.

In addition, the colorants used to color the film include titanium white,
Ultramarine blue, carbon black, etc. can be widely used.

The laminated film according to the present invention is prepared by first mixing polyethylene B and a colorant using a conventional method such as a master patch method or a tri-blend method, and then mixing polyethylene B with a colorant using a conventional method such as a master patch method or a triblend method. It is produced by coextrusion with polyethylene A using a T-die method, an inflation method, or the like. The above-mentioned coextrusion may be performed by adhesion inside the goo or outside the goo.

゛ However, in the extrusion lamination method, if the cooling roll used is mirror-finished, it will fuse, so it is necessary to use a roll with a satin finish, which causes the film surface to become rough, lose its luster, and reduce the appearance. I can't make beautiful films.

The laminated film formed by the above-mentioned coextrusion is preferably 10 μm or less because the thinner the layer of colored polyethylene B can be coextruded, the more gloss it retains and the stiffer it becomes.

In the present invention, it is better to color polyethylene B at the same concentration than polyethylene A, so polyethylene A and polyethylene B are impregnated with a coloring agent at a higher concentration and placed on the side that is as visible as possible. They have found that it is convenient to use, and that the amount of coloring agent used can be reduced.

In the above description, polyethylene A is not colored, but it may be slightly colored to form a laminated film.

[Examples of the present invention, comparative examples]

Next, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Example 1 Density: 0.950 g/cc, M I: 0.0
5 g/10 min of I-lyethylene A (HDPE
) and density: 0.92011/CC.

M I: 211/10m1n of I-lyethylene B
(LLDPE) as a coloring agent, titanium white pigment,
Using Rutile Tyso R-680 (trade name), LLDPE
A mixture of 100 parts by weight and 10.5 parts by weight of pigment was co-extruded using an inflation method with a diameter of 10 (1 m+, die temperature: 200°C, blow-up ratio: 2.5). A laminated film with a DPE layer thickness of 18 μm and an LLDPE layer thickness of 7 μm was formed, and the width was 390 mm.
□A bag with a length of 550 vans was created.

Example 2 As polyethylene B, density: 0.9201//cc
.

M I: 2.9/A bag was made in the same manner as in Example 1 except that LDPE of 10 m1n was used.

Comparative example 1 Density: 0.950 g/cc, M I: 0.0
5 Vlo min HDPE was mixed with the same coloring agent as in Example 1 in the same proportions, and a film was formed by the inflation method with Gouy diameter = 100 and Gouy temperature = 200°C to form a single layer with thickness = 25μ. The film was molded and a bag was made in the same manner as in Example 1.

Comparative Example 2 Density: 0.9201/ccSM I: 21/1
A bag was produced by molding a single-layer film in the same manner as in Comparative Example 1, except that 0 ml of LDPI was used and the Goo temperature was 190°C.

Comparative Example 3 Density: 0.92011/ccSM I: 2 jj
A bag was produced by molding a single-layer film in the same manner as in Comparative Example 2 except that LLDPE of 10 ml/n was used.

The physical properties of the bags prepared in the above Examples and Comparative Examples were measured. The results are shown in Table 1.

Table 1: Q It can be seen that the bags of the present invention have excellent gloss, firmness, good color impression, and high puncture strength, which is much superior to bags made of single-layer film. Further, the amount of pigment used can be about 28 tons for a single layer film.

[Effects of the present invention]

As described above, the bag according to the present invention is suitable for use as a bag because it has excellent gloss, is sturdy, has a beautiful appearance with the colored color, and has high puncture strength, and also has a laminated film. If an appropriate amount of coloring agent is added to one of the two, only a small amount or no coloring agent can be added to the other, which has the advantage that the amount of coloring agent used can be significantly reduced.

Claims (1)

[Claims] Polyethylene with a density of 0.940 g/cc or more and a density of 0.93 containing a colorant with a higher concentration than the polyethylene.
A bag comprising a laminated film coextruded with polyethylene having a density of 0 g/cc or less, and having a layer of polyethylene having a density of 0.930 g/cc or less on the outside.