JPS585355A - Shrink wrapping film - Google Patents

Abstract

PURPOSE:To provide an oriented shrink wrapping film which has nerviness, good slip characteristics and excellent machine wrappability, is non-toxic and does not cause blocking, by extruding a compsn. consisting of a styrene/butadiene block copolymer and polystyrene. CONSTITUTION:50-98wt% styrene/butadiene block copolymer composed of 65- 90% styrene and 10-35% butadiene, 50-2wt% polystyrene having a heat distortion temp. of 90 deg.C or higher and, if necessary, a lubricant such as ethylenebisamide and an antistatic agent such as glycerol fatty acid ester are blended together. The resulting compsn. is supplied to an extruder, and extruded into a film by using a T-die or a ring die. The film is mono- or biaxially oriented to obtain the titled film. USE:Covering of an opening of a container, etc., label wrapping, twist wrapping, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stretched shrink wrapping film that is stiff, has good slip properties, and has excellent machine packaging suitability.

Traditionally, so-called shrink-wrapping fill for various products has been used using polyvinyl chloride-based tortoise, but recently its toxicity has become a problem, as well as its poor transparency and stiffness. It has been pointed out that it is weak and has poor specifications, so it has a poor suitability for mechanical packaging. As a non-toxic O-shrink packaging film for large polyvinyl chloride-based products,
Polypropylene-based materials have come to be used, but this material leaves abrasive # on the surface and has a poor appearance, and requires high temperatures to shrink, and the temperature range in which it can be contracted is narrow, making it difficult to work with. It had disadvantages such as poor elasticity and easy troubles in controlling the shrinkage temperature. ◎It is possible to improve these disadvantages by adding a polypropylene resin and an appropriate resin such as butyne. 4 Ideas However, although these 4 problems caused by polyproylene resin alone can be improved, they still have drawbacks such as stiffness and weak stiffness, making them impractical. It wasn't.

As a result of intensive research to improve these drawbacks, the inventors of the present invention have found a material that has firmness, good slipperiness, and excellent mechanical packaging suitability.
Kameno has succeeded in developing a new shrink packaging film that is non-toxic, has excellent transparency, and does not cause the blockage phenomenon.
011. It contains 50-98% by weight of a styrene-butadiene block copolymer with a butadiene content of 10-4511% and 50-3% by weight of polystyrene having a heating temperature of 90°C or higher, and is made by stretching. .

In 〇zero-, which will be described in detail about the present w4 below, the styrene content is 65~eol, buta dz
A styrene-butadiene block copolymer with a melt index of 10 to 35 is one in which M and Z (melt index X) are 1.0 to 35.
10.0 is preferably in the range of 1.0-i, o, and polystyrene is a general resin, with a heat-resistant grade and a heat distortion temperature (according to the test method of sxax-max No. 1). ) is required to be heat resistant to 90°C or higher, and in this case, the preferred tL< is in the range of 92 to 96°C.
Certain things lead to favorable results.

The present invention has a styrene content of 66 to 90 tatami, as described above.
A styrene-butadiene block copolymer with a dichloromethane content of 60 to 98 wt.
A resin containing 0 to 3 parts by weight is used, and the reason for this is the following hyperactivity. For example, styrene content 66-90
Unfortunately, a film made of tyrene-butadiene block copolymer alone with a butadiene content of 0~rsssox has poor elasticity and poor shrinkage workability during packaging work, and a film made of only polystyrene has poor impact resistance. It has the disadvantage of being easily damaged.

On the other hand, in the present invention, since the above-mentioned specific polymer is blended with specific weights of specific polystyrene, the above-mentioned drawbacks caused by these alone can be eliminated. The reason why the copolymer was limited to include 98% by weight and 50 to 8% by weight of I-Restyrene is that if the copolymer is less than 50% by weight and more than 60% by weight, the impact resistance of the film will be poor and damage or cracks will occur. On the other hand, if the weight of the copolymer is more than 98 tatami and the weight of polymethylene is less than 98 tatami, the FiW will be weak, the packaging workability and shrinkage workability will be poor, and the bulkiness and crispness of the packaged product will be reduced. This is because the resin lacks tactility and cannot be expected to be widely used. ◎The above resin is used in the present invention, but if a high degree of slipperiness is required for FIL AK, a well-known lubricant may be added. At this time, ethylene bisamide, fatty acid amide, etc. can be used as a lubricant.An antistatic agent may also be added depending on the KIB'llK.In this case, well-known antistatic agents such as glycine fatty acid ester, sorbitan fatty acid ester, etc. I can give examples of

To prepare the film of the present invention from the above-mentioned compound consisting of the above-mentioned compositions II and 11, a conventional technique for making a film from a thermoplastic resin is used, for example, by applying the compound to an extruder! A 611F die is produced using a die or an annular die*, and the material is then drawn along a longitudinal axis, a weft axis, or a weft axis, depending on the application.

No. 11 [1] shows the film according to the present invention used as an opening cover for a food customer, (1) shows a food container, (1s) shows a cover made of film, and 1s shows a sealing part. As shown in this example, it is used as an opening cover for food containers.%/T
h Ishibakai said that #film may be stretched in either the l-axis or bi-axis.No. When using a film label for label packaging as in this example, the film is stretched in the latitudinal and horizontal directions.
It is preferable to use this. 1! It goes without saying that the articles to be packaged are not limited to the above-mentioned containers and bottles, but also include those of all types and uses. Genproc copolymer: IF6 weight (styrene content: approximately 5 mm, weight: approximately 11 mm)
Polystyrene (heat distortion temperature: 9.3℃): 88
Weight - Blend the above ingredients and extrude this using Tedai extruder 1
1i! After stretching, it was stretched 1 times in the weft direction using a tenter set stretching machine to obtain a film for shrink wrapping.・This film had stiffness, good slip properties, and was non-toxic.◎Use this film! When the bottles were labeled and packaged as shown in the IIE diagram, it was possible to carry out the mechanical packaging smoothly〇〇〈Example 2) The same ingredients as in Example 1 were mixed, and this was done using the same equipment. A film was formed by extrusion, and then stretched 14 times and 6 times in the direction using a lithographic stretching machine to obtain a flexible, non-toxic shrink wrapping film with good slip properties.Using this film, as shown in Figure 1, When used as a cover for the opening of a container, aba-p was formed on the surface.
The film of the present invention has no cape and has an excellent appearance.As described above, the film of the present invention is non-toxic compared to the conventional film, has strong elasticity and good slip properties, and has excellent mechanical packaging properties. It has good transparency and is excellent in that it does not cause blocking phenomena, and is expected to be suitable for applications such as packaging for covering the opening of containers, label packaging, twist-second packaging, etc., and is also used for packaging various products. You can expect the effect of increasing the product value of goods◎

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams showing examples of the use of the film according to the present invention. (1)--Food container, (ri...opening cover, (11)
--Seal part, (4) --Bottle, (6) --Label. Patent applicant Gunze Co., Ltd. Figure 7 Figure 2 435-

Claims (1)

[Claims] 1. Styrene content: 65~9°, Butadiene content: 10
~s8 O styrene-butadiene block copolymer 50
Shrink wrapping film 0 characterized by containing ~98 weight polystyrene and polystyrene SO having a heat deformation temperature of 90'IC or more ~ dew weight, and being stretched.