JPH08436B2 - Heat shrinkable tube - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a general heat shrinkable packaging material,
The present invention relates to a shrink label for various bottles, containers, cans, etc., and particularly to a heat-shrinkable tube used as a cap seal.

[0002]

2. Description of the Related Art Vinyl chloride resin is mainly used in conventional heat-shrinkable tubes. However, this vinyl chloride resin generates chlorine gas when burned. Chlorine gas has become a major social problem because it damages incinerators and causes serious environmental damage.

In particular, cap seals and the like used in ordinary households are extremely difficult to recycle by classifying and sorting by material, and are often disposed of together with household household waste. This is a big social problem, and the advent of alternatives is highly desired.

[0004]

The heat-shrinkable tube is
As is well known, it shrinks greatly by heating, but as a basic condition, it is desired that it has a heat shrinkability at low temperature heating and a small natural shrinkage, and a shrinkage suitable for use is desired. The contraction rate is as follows: longitudinal contraction rate (machine direction): 10% or less, transverse contraction rate (right angle direction): 45%
That is all. Polypropylene, polyethylene, polystyrene, polyethylene terephthalate, etc. are considered as the non-polyvinyl chloride resin system that does not contribute to environmental destruction.

However, it is difficult to obtain a sufficient shrinkage ratio suitable for use with polypropylene and polyethylene, and polystyrene has a large natural shrinkage ratio and is difficult to stably produce. Further, the quality retention after production is unstable. Since these resins are soft and have no rigidity, they are not suitable for improving the production efficiency of an automatic machine.

[0006] Polyethylene terephthalate heat-shrinkable tubes are excellent in shrinkage rate suitable for use and suitability for automatic machines, but they are uncommon because of high raw material cost.

An object of the present invention is to provide a heat-shrinkable tube which solves the above problems.

[0008]

The present invention is based on a cyclic olefin-based copolymer resin: 100 parts as a main component, and another olefin-based resin; 2 parts or more and 50 parts or less, and a compatibilizing agent: 10 parts or less. The present invention relates to a heat-shrinkable tube characterized in that In addition, the present invention comprises a cyclic olefin-based cobolimer resin: 100 parts as a main component, other olefin-based resins: 2 parts or more and 50 parts or less, a compatibilizer: 10 parts or less, other thermoplastic resin, antistatic. The present invention relates to a heat-shrinkable tube in which an agent, a lubricant, inorganic fine particles, and a color pigment are added and mixed.

[0009]

The cyclic olefin-based copolymer resin referred to in the present invention includes, but is not limited to, Apel resin (manufactured by Mitsui Petrochemical Industry Co., Ltd.) and the like. Cyclic Olefin Copolymer Resin A single heat-shrink tube is very rigid and feels similar to a cellophane film. It is inflexible and produces a metallic sound when played with a finger, and whitening and cracking when bent. Also, when this tube is hung on an automatic machine, there is a metallic sound that makes you hear the ears,
Further, it cannot be a heat-shrinkable tube that can withstand use due to cracks and pinholes. That is the tube indicated by A in Table 1.

Examples of the other olefin resin used in the present invention include, but are not limited to, polyethylene, polyamito, ethylene vinyl acetate copolymer and the like. By adding another olefin resin to the cyclic olefin copolymer resin, appropriate flexibility is obtained, and workability and suitability for an automatic machine are improved. If the addition amount is less than 2 parts with respect to 100 parts of the cyclic olefin-based copolymer resin, there is no flexibility, and cracks occur when it is hung on an automatic machine, and the effect is not recognized. Like the tube shown by B in Table 1, it becomes too soft when it exceeds 50 parts.
Therefore, in the range of 2 parts or more and 50 parts or less, it is preferable to adjust the addition amount according to the type of resin to be added and the suitability of an automatic machine. The tube indicated by C in Table 1 is an example.

Other features than the above are that the shrinkage rate is improved, and tearability in the longitudinal direction, hiding power, lubricity, flexibility after heat shrinkage, and the like are imparted. Specifically, the vertical shrinkage is reduced and the horizontal shrinkage is improved, vertical tearing is ensured, perforations such as cap seals can be omitted, and the base is invisible, so the finish is neat and color pigments are added. The amount can be saved, clear printing is easy, the lubricity of the tube is good, the use of lubricant can be saved, and the flexibility is retained even after heat shrinkage, so the bag can be crushed even if the coated part is impacted. Therefore, the quality of the coating can be strongly maintained. These lead to cost reduction.

However, if other olefinic resins are added to the cyclic olefinic copolymer resin, the lumps are generated due to insufficient compatibility. The generation of seeds is remarkable with the naked eye when the addition amount is 7 parts or more. The spots have a bad appearance,
It reduces the quality of the coating and makes clear printing impossible. There are also some bad spots where the print is missing. Even if the amount of addition is small and it is not a problem in appearance, the quality may deteriorate.

Examples of the compatibilizing agent, that is, the polymer modifier, used in the present invention include, but are not limited to, Bennett resin (olefin copolymer resin manufactured by Teikoku Kagaku Co., Ltd.). . The effect can be enhanced by adding 10 parts or less, preferably 5 parts or less.
As a result, the cyclic olefin-based copolymer resin and the other olefin-based resin can be compatibilized with each other to eliminate the spots. Moreover, the effect of lowering the vertical shrinkage and improving the horizontal shrinkage was observed. That is the tube exemplified in D of Table 1.

The above-mentioned cyclic olefin-based copolymer resin, other olefin-based resin, compatibilizer, etc. do not contain chlorine, and chlorine gas is not generated by combustion. Since the molecule is composed of carbon and hydrogen, only water and carbon dioxide are generated by combustion.

[0015]

[Table 1]

In the production of a specific heat-shrinkable tube, first, the raw materials are heated and mixed to form the raw tube. At that time, if necessary, in addition to the above raw materials, depending on the required quality,
Other thermoplastic resins, antistatic agents, lubricants, inorganic fine particles, additives and fillers such as color pigments may be blended. The raw tube is then placed on a stretcher. At that time, the stretching temperature is 8
Uniaxially or biaxially stretching is performed at 0 to 110 ° C., preferably 90 to 98 ° C., and longitudinal stretching of 1.5 times or less and lateral 1.5 to 2.5 times.

The finished heat-shrinkable tube was placed in boiling water to
The contraction rate when immersed for 0 seconds is 30% or less, preferably 10% or less, in the longitudinal contraction rate, and 40% or more, preferably 50% or more in the transverse contraction rate. If it deviates from this range, various troubles are likely to occur, such as a poor finished state when coated on the coating. The tube of the present invention shown by D in Table 1 has an ideal result of a longitudinal shrinkage of 8% and a lateral shrinkage of 50%.

[0018]

EXAMPLES Examples according to the present invention will be described below, but it goes without saying that the present invention should not be limited to these examples.

[0019]

[Table 2]

The first embodiment of A in Table 2 is 100 parts by weight of the apel resin as the cyclic olefin copolymer resin,
Polyethylene as other olefin resin: 10
And a Bennet resin (5 parts) as a compatibilizer (polymer modifier) are added and mixed, which is a heat-shrinkable tube. Instead of polyethylene, heat shrinkage was obtained by adding and mixing 10 parts of polyamito in the second embodiment of B in Table 2 and ethylene vinyl acetate copolymer in the third embodiment of C of Table 2 respectively. It is a sex tube.

Table 2 compares the tear strengths of the heat-shrinkable tubes of 100% vinyl chloride with those of the above-mentioned first to third examples. It is clear from this experiment that the heat-shrinkable tube of the present invention has excellent tearability.

[0022]

As described above, the heat-shrinkable tube according to the present invention does not contain vinyl chloride, is suitable for the conventional automatic machine for producing a heat-shrinkable tube, and has an ideal heat-shrinkage rate. It can be realized and has excellent features such as tearability in the vertical direction, hiding power, printability, lubricity, and flexibility after heat shrinkage.It is particularly suitable for cap seals, etc. It has various effects, such as being able to be incinerated together with other garbage and having no elements that lead to environmental damage.

Claims (2)

[Claims] 1. A cyclic olefin-based copolymer resin: 10
A heat-shrinkable tube comprising 0 parts as a main component, and another olefin resin: 2 parts or more and 50 parts or less and a compatibilizing agent: 10 parts or less. 2. A cyclic olefin-based copolymer resin: 10
0 parts as the main component, other olefinic resin: 2 parts or more and 50 parts or less, compatibilizer: 10 parts or less, and other thermoplastic resin, antistatic agent, lubricant, inorganic fine particles, color pigment are added and mixed. A heat-shrinkable tube characterized in that