JP2775137B2 - Stretch 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 stretch film, and more particularly to a stretch film suitable as a household wrap film used for food packaging.

[0002]

2. Description of the Related Art Conventionally, as a stretch film used as a so-called wrap film for home use, a film is prepared by blending polyvinyl chloride (PVC) or polyvinylidene chloride (PVDC) with an appropriate amount of a plasticizer. And those obtained by forming a film of polyethylene (PE) having an appropriate density with good transparency are known.

[0003] However, a wrap film made of such a material becomes too soft at a high temperature and cannot maintain its shape as a film. In addition, if a highly oily food is directly wrapped and heated in a microwave oven or the like for a relatively long time, there is a problem that the film melts or breaks, and cannot be stuck to the food.

On the other hand, polyethylene terephthalate (PE)
Although wrap films using plastics having good heat resistance such as T) and polyamide (PA) are also known, these films have a problem that it is difficult to impart tackiness.

Also, a wrap film using a 4-methyl-1-pentene polymer having excellent heat resistance and adding a liquid polybutene (a polymer containing isobutylene as a main component) as a tackifier is known. As described in Japanese Unexamined Patent Publication No. Hei 5-239291, a film of such a composition has a drawback that a blocking phenomenon is developed with time and it is extremely difficult to take out the film from the box.

Accordingly, an object of the present invention is to provide a stretch film which is excellent in heat resistance and adhesiveness and also excellent in handleability.

[0007]

The present inventors have proposed methyl-
Focusing on the fact that the 1-pentene polymer has a high melting point, and as a result of repeated studies on a method of imparting tackiness thereto, when a composition containing a specific amount of liquid paraffin is used for a stretch film, excellent heat resistance is obtained. The present inventors have found that both properties and appropriate tackiness can be obtained, and arrived at the present invention.

That is, the stretch film of the present invention comprises:
It is characterized by having at least a layer comprising a composition containing 99 to 70 parts by weight of a methyl-1-pentene polymer and 1 to 30 parts by weight of liquid paraffin.

The methyl-1-pentene polymer used in the present invention is 4-methyl-1-pentene and / or 4-methyl-1-pentene.
In addition to 3-methyl-1-pentene homopolymer, 4-methyl-1
-Pentene and / or 3-methyl-1-pentene and other
Includes copolymers with 1-alkenes. The 1-alkene may be used alone or in combination of two or more. The content of 1-alkene in the copolymer is 10% or less when 1-alkene of C _{2 to} C ₅ is used, and 1-alkene of C _{6 to} C ₁₀ is used.
8% or less when using the alkene, the C ₁₁ -C ₁₄ 1-
When an alkene is used, it is preferably at most 5%. When these are used in combination, the total of 1-alkene is preferably 5% or less. Further, such a polymer or copolymer modified with maleic anhydride can also be used as a methyl-1-pentene-based polymer. In this case, the content of maleic anhydride should be 10% by weight or less. preferable. As a methyl-1-pentene polymer,
Preferred are polymers of 4-methyl-1-pentene.

Next, the liquid paraffin used in the present invention preferably has an initial boiling point of 149 ° C. or more and a final boiling point of 343 ° C. or less from the viewpoint of safety and health. Further, those having no odor and no kerosene odor are preferable. Furthermore, the condition as a food wrap film, that is, the ultraviolet absorbance (the maximum absorbance per 1 cm of optical path length) is 28.
Those satisfying the conditions of 4.0 or less at 0 to 289 nm, 3.3 or less at 290 to 299 nm, 2.3 or less at 300 to 329 nm, and 0.8 or less at 330 to 360 nm are preferable.

The stretch film of the present invention is characterized in that it has a layer made of a resin composition containing the above-mentioned methyl-1-pentene polymer and liquid paraffin.
In this composition, liquid paraffin has a ratio of 1 to 30 parts by weight to 99 to 70 parts by weight of the methyl-1-pentene polymer, and preferably 80 to 95 parts by weight of the methyl-1-pentene polymer. Liquid paraffin in a proportion of 5 to 20 parts by weight. If the amount of the methyl-1-pentene polymer is less than 70 parts by weight, sufficient heat resistance cannot be exhibited,
If it exceeds 99 parts by weight, sufficient tackiness cannot be obtained.
If the liquid paraffin is less than 1 part by weight, sufficient tackiness cannot be obtained, and if it exceeds 30 parts by weight, the liquid paraffin is leached out on the film surface to impair the transparency of the film.

In addition to the methyl-1-pentene polymer and liquid paraffin, the above-mentioned composition includes, for example, a butene-1 polymer for improving cold resistance; a fatty acid amide and a fatty acid bisamide for lightening the peeling of the film; A component such as α-methylstyrene / vinyltoluene hydrogenated resin may optionally be included in an amount of 10 parts by weight or less to increase tackiness. Further, conventional antioxidants, inorganic fillers, antistatic agents, antifogging agents, ultraviolet absorbers, colorants, heat stabilizers, nucleating agents, and the like can be included as necessary.

[0013] The stretch film of the present invention may be a monolayer or multilayer film of the composition described above. The thickness of the film is preferably from 3 to 50 μm, particularly preferably from 10 to 20 μm.

The stretch film of the present invention also has at least one layer composed of the above composition, and optionally has a layer composed of a propylene polymer and / or a layer composed of a butene-1 polymer. It can be a multilayer film. When these polymers are contained in the composition, the propylene-based polymer has excellent heat resistance to some extent and is inexpensive, but the transparency of the film is impaired, and the butene-1 polymer is not used. Although it is relatively well compatible with the components of the composition and can provide cold resistance, it imparts heat sealability to the film, and the films tend to stick together after heating. Therefore, without containing these polymers in the composition, each layer is formed,
By laminating with a layer made of the composition to form a multilayer, the above disadvantage can be solved and an advantage can be provided.
A multilayer film in which such a layer is placed as an intermediate layer and a layer made of the composition is laminated on both sides thereof is preferred.

The method for producing the stretch film of the present invention is not particularly limited. For example, after each component of the above composition is supplied to an extruder and melt-kneaded, a known film-forming method such as T-die and inflation is used. Can be used to form a film. In the case of a multilayer film, the film can be formed using two or more extruders and one multilayer die. In addition, in order to increase heat resistance, setting property, and strength, stretching may be performed by a tenter method, a tubular method, or the like.

[0016]

The following examples further illustrate the present invention. Example 1 Methyl- 1 -pentene polymer (Mitsui Petrochemical Co., Ltd.)
90 parts by weight, manufactured by Esso Petrochemical Co., Ltd., Christol 352, odorless, first boiling point
149 ° C., final boiling point 343 ° C.) 10 parts by weight were supplied to an extruder (Yamaguchi Seisakusho, 40 m / m), melt-kneaded at 280 ° C. and 40 rpm, and then a 15 μm thick film was formed with a T-die. Created. This film was tested as a household wrap film shown below. Table 1 shows the results. (1) Heat resistance The heat resistance temperature was measured according to the method for indicating the quality of household goods. (2) Adhesion The sticking property to the glass container was evaluated by a questionnaire by 10 panelists. The evaluation criteria were as follows: ：: 9 or more persons judged that the adhesiveness was good ○: 7 to 8 persons judged that the adhesiveness was good △: 4 to 6 persons judged that the adhesiveness was good X: judged as good: 7 or more judged that the tackiness was poor. (3) Sticking together of the heated films Combine 100g of fried chicken in a film and microwave (National NE-M330, 500W high frequency, 940W power consumption)
The adhesion of the films after heating for 3 minutes was evaluated by a questionnaire by 10 panelists. The evaluation criteria were as follows: ：: 9 or more persons judged that the sticking was good ○: 7 to 8 persons judged that the sticking was good Δ: 4 to 6 persons judged that the sticking was good X: Seven or more people judged that sticking was poor. (4) Ease of taking out of the box A small roll of a 20m long film is taken at 40 ° C.
After storing for a week, they were placed in a household wrap makeup box, and the ease of withdrawal was evaluated by a questionnaire by 10 panelists. The evaluation criteria were as follows: ◎: 9 or more persons judged that it was easy to pull out ○: 7 to 8 persons judged that it was easy to pull out Δ: 4 to 6 persons judged that it was easy to pull out ×: More than seven people judged it difficult to withdraw. (5) FDA standard It was checked whether it meets the FDA standard (restriction of additives). Example 2 Methyl-1-pentene polymer (Mitsui Petrochemical Co., Ltd.)
, RT-20), liquid paraffin (Esso Petrochemical Co., Ltd.)
Except for using 85 parts by weight, 5 parts by weight, and 10 parts by weight of a butene-1 polymer (manufactured by Mitsui Petrochemical Industries, Ltd., Buron M3080), respectively. Melt-knead in the same manner as in Example 1
A 5 μm film was made. About this film,
The same test as in Example 1 was performed. Table 1 shows the results. Example 3 Propylene polymer sheet (manufactured by Sumitomo Chemical Co., Ltd.)
Fs-2011D), the same composition as in Example 1 (methyl
-1- 90 parts by weight of a pentene polymer and 10 parts by weight of liquid paraffin) are coextruded and laminated so that the layer thickness ratio becomes 1: 2: 1, and then the laminate is biaxially stretched. Using a machine (manufactured by Toyo Seiki Co., Ltd.), the film was stretched 5 times vertically and horizontally to prepare a film. The film thickness was 15 μm.
The same test as in Example 1 was performed on this three-layer film. Table 1 shows the results. Comparative Example 1 Methyl- 1 -pentene polymer (Mitsui Petrochemical Co., Ltd.)
A film was prepared in the same manner as in Example 1 using only RT-20). The thickness of the film was 15 μm.
The same test as in Example 1 was performed on this film. Table 1 shows the results. Comparative Example 2 Methyl-1-pentene polymer (Mitsui Petrochemical Co., Ltd.)
90 parts by weight of liquid polybutene (isobutylene-based polymer, manufactured by Idemitsu Petrochemical Co., Ltd.)
100R) Except for using 10 parts by weight, melt kneading was carried out in the same manner as in Example 1 to prepare a film having a thickness of 15 μm. The same test as in Example 1 was performed on this film. Table 1 shows the results.

[0017]

[Table 1]

[0018]

EFFECTS OF THE INVENTION The stretch film of the present invention is excellent in heat resistance, has appropriate adhesiveness, and is easy to handle. Suitable for. In addition, since an oily food or the like can be directly wrapped and heated in a microwave oven, the field of cooking using a microwave oven can be expanded.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 23/20 C08L 23/20

Claims (5)

(57) [Claims] 1. A methyl-1-pentene polymer 99-7.
A stretch film having at least a layer comprising a composition comprising 0 parts by weight and 1 to 30 parts by weight of liquid paraffin. 2. The stretch film according to claim 1, wherein the methyl-1-pentene polymer is a 4-methyl-1-pentene polymer. 3. The stretch film according to claim 1, which has a thickness of 3 to 50 μm. 4. A liquid paraffin having an initial boiling point of 149 ° C.
The above and the final boiling point is 343 ° C or lower.
The stretch film according to any one of the above. 5. The stretch film according to claim 1, which is a multilayer film having a layer made of a propylene polymer and / or a layer made of a butene-1 polymer.