JPS62216726A - Shrinkage packaging film - Google Patents

Abstract

PURPOSE:To prevent blocking of a vinyl coated product, by applying biaxial orientation to a sheet obtained by adding inorganic particles having a specific diameter to polyvinyl chloride resin at the specific rate. CONSTITUTION:A shrinkage packaging film is composed of 100wt part polyvinyl chloride resin, 0.3-0.1wt part inorganic particles and various kinds of necessary additives. As the inorganic particles, for example, silica or calcium carbonate or magnesium carbonate whose mean particle diameter falling within a range of 6-10mum is used. The additives are a stabilizer and lubricant. A sheet having those composition is obtained through extrusion molding, to which heat shrinkability is given by applying orientation in an axial direction to the same. Although the film deteriorates slightly in its transparency, it is extremely superior in blocking prevention effect and suitable for shrinkage packaging of a vinyl coated product.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a shrink packaging film made of polyvinyl chloride O11, particularly for packaging products such as Niazol cans whose surfaces are coated with beer resin. Regarding films suitable for
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(Prior Art) Shrink wrapping films made of polyvinyl chloride resin (hereinafter referred to as PVC), that is, heat-shrinkable films, are widely known.
It is used for packaging various goods.

(Problem to be solved by the invention) However, with this PVC film, products such as Niazol cans and medicine boxes that have a glossy vinyl coat (usually vinyl chloride-vinyl acetate copolymer resin) on their surfaces shrink. When packaged, the film and product may block due to the heat generated during packaging, giving the appearance of liquid intervening, which greatly reduces commercial value.

This problem is that PVC film is soft (contains a lot of plasticizer)
Significant in cases of

As a countermeasure to this problem, there is a method of dispersing starch powder or the like on the surface of the film, but this method has drawbacks such as contaminating the contents and impairing the heat sealability of the film, and is not a satisfactory solution.

(Means for solving and overcoming the problems) The present invention solves the above-mentioned conventional problems and provides a shrink wrapping film that does not cause blocking even for vinyl coated products.

That is, the present defense claims that 0.3 to 0.3 to 1000 ff of inorganic particles with an average particle size of 6 to 10 μn are added to 2 parts of 1100 ff of polyvinyl chloride resin.
This is a shrink packaging film made by biaxially stretching a sheet containing 1.0 parts by weight, and the unevenness of the film surface eliminates blocking with the product.

A detailed description of the present invention follows.

The film of the present invention contains 100 parts of PVC and 0 parts of inorganic particles.
．． It consists of 3 to 1.0 parts of weight and various necessary additives.

The main PVC may be one that is normally used for extrusion molding, and for example, a homopolymer resin with an average degree of polymerization of about 700 to 1100 or a resin containing a small amount of polysynthetic components can be used.

The inorganic particles are, for example, silica, calcium carbonate, magnesium oxide, magnesium carbonate, etc., and it is necessary to use particles with an average particle size of 6 to 10 ulN, which is quite large.

It has been found that in order to prevent blocking with vinyl products, the irregularities imparted to the film surface must be quite large.

If the average particle size of the particles is smaller than 6 μm, the unevenness formed on the film surface will be too small, and even if it is effective in preventing bulging immediately after packaging, it will not be possible to prevent the film from being placed in a high-temperature atmosphere after packaging. Cover your blocking with raw material.

Furthermore, if the average particle diameter of the particles exceeds 10 μm, the film thickness is usually about 15 to 25 μm, which adversely affects film production and also deteriorates the appearance of the film.

If the average particle size is in the range of 6 to 10 Ltm, blocking can be effectively prevented by adding a relatively small amount, and as a result, the transparency of the film is not significantly impaired.

Addition of particles <g is 0.3 per 100 crushed portion of PVC
-1.0 parts by weight.

If it is less than 0.3 weight R1 part, the number of protrusions due to particles will be small when it is made into a biaxially stretched film, and the anti-blocking effect will be small.If it exceeds 1.0 weight part, the film appearance will become thick (1f1). become.

], the lume usually contains about 1 part or more of a plasticizer such as DOP in order to improve the shrinkage finish, facilitate heat sealing, and improve the feel. Since plasticizers with low i-modity do not inherently cause blocking, it is not necessary to add particles.

The film of the present invention is produced by adding necessary additives such as stabilizers and lubricants to the above components. A sheet having the following composition is made by extrusion molding, etc., and then stretched in biaxial directions to impart heat shrinkability. do.

The heat shrinkage rate used is one that shrinks by about 30 to 50% in each of the two axial directions when placed in hot water at 100° C. for 1 minute, for example.

Although the film of the present invention slightly decreases in transparency,
The anti-blocking effect is extremely good, and the anti-blocking effect is extremely good.
Suitable for shrink-wrapping products.

(Example) To 100 parts of a polyvinyl chloride resin with an average degree of polymerization of 1050, 3 parts of an organotin stabilizer, 15m161 parts of a plasticizer DOP, and 0 and 5 parts of a lubricant (polyethylene wax) were added, and the mixture was roughly mixed. Inorganic particles (silica) shown in Table 1 were added to form a sheet with a thickness of 60 μm by extrusion molding, and this was stretched for 24 rS in each of the vertical and horizontal directions to a thickness of 1
The film had a heat shrinkage rate (100° C.) of 43% in both length and width directions of 5 μm.

Then, the vinyl-coated Niazol cans were shrink-wrapped using the q film and heated to 3F immediately after packaging and at 45°C.
” I looked at Shun Tsugu's blocking state.

The results are also listed in Table 1.

In the J3 triple table, the average particle size of the particles was measured by the sedimentation method, and the haze was measured by J (SK6714).

In addition, the blocking state is determined by checking whether the packaging has a good appearance or not.
Δ indicates the appearance that some liquid is present.
A case where a state in which a liquid was present occurred throughout the sample was designated as X.

Table 1 It is clear from Table 1 that the film of the present invention (No. 3
In cases of ~5), no prolagging was observed even after being left at high temperatures, the transparency was relatively good, and film production could be carried out stably.

Claims (1)

[Claims] Average particle size 6 to 100 parts by weight of polyvinyl chloride resin
A shrink wrapping film made by biaxially stretching a sheet to which 0.3 to 1.0 parts by weight of 10 μm inorganic particles are added.