JPH07165940A - Stretch-wrap film - Google Patents

Abstract

PURPOSE:To obtain a stretch-wrap film having a layer of a composition containing a methyl-1-pentene polymer and a liquid saturated hydrocarbon, exhibiting excellent heat-resistance and tacky adhesiveness, having excellent handleability and useful as a domestic wrapping film heatable in a microwave oven. CONSTITUTION:This stretch-wrap film has a thickness of preferably 5-30mum and has a layer of a composition containing (A) 99-70 pts.wt. (preferably 80-95 pts.wt.) of a methyl-1-pentene polymer (preferably 4-methyl-1-pentene polymer) and (B) 1-30 pts.wt (preferably 5-20 pts.wt.) of a liquid saturated hydrocarbon (preferably a paraffinic or naphthenic process oil, white mineral oil, etc., having an initial boiling point of >=149 deg.C and a stop point of <=343 deg.C, especially preferably liquid paraffin). The film may be a multi-layer film having a propylene polymer layer and/or a butene-1 polymer layer.

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 applications and the like.

[0002]

2. Description of the Related Art Conventionally, as a stretch film used as a so-called household wrap film, a film is formed by blending polyvinyl chloride (PVC) or polyvinylidene chloride (PVDC) with an appropriate amount of a plasticizer. And those obtained by forming polyethylene (PE) with an appropriate density into a transparent film are known.

However, the wrap film made of such a material becomes too soft at a high temperature and cannot retain its shape as a film. Further, when a highly oily food is directly wrapped and heated in a microwave oven or the like for a relatively long time, there are problems that the film is melted or torn, and the film cannot be attached to the food.

On the other hand, polyethylene terephthalate (PE
A wrap film using a heat-resistant plastic such as T) or polyamide (PA) is also known, but these films have a problem that tackiness is difficult to impart.

Further, a wrap film obtained by using a 4-methyl-1-pentene polymer having excellent heat resistance and adding liquid polybutene (a polymer containing isobutylene as a main component) as a tackifier is particularly As described in Japanese Patent Laid-Open No. 5-239291, a film of such a composition has a drawback that it exhibits a blocking phenomenon over time, which makes it extremely difficult to take it out of the box.

[0006] Therefore, an object of the present invention is to provide a stretch film which is excellent in heat resistance and tackiness and is easy to handle.

[0007]

MEANS FOR SOLVING THE PROBLEMS The present inventors have found that methyl-1
-Focusing on the high melting point of the pentene polymer, as a result of repeated studies on the method of imparting tackiness to it, the use of a composition containing a specific amount of liquid saturated hydrocarbon in a stretch film produced excellent results. The present invention has been completed by finding that both heat resistance and appropriate tackiness can be obtained.

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

The methyl-1-pentene polymer used in the present invention is 4-methyl-1-pentene and / or
In addition to homopolymer of 3-methyl-1-pentene, 4-methyl-1
-Penten 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 a C _{2 to} C ₅ 1-alkene is used, and 1 to ₆ of C _{6 to} C ₁₀
When using alkene, 8% or less, 1-of C _{11 to} C ₁₄
When using an alkene, it is preferably 5% or less. When these are used in combination, the total amount of 1-alkene is preferably 5% or less. Further, such a polymer or copolymer modified with maleic anhydride can also be used as the methyl-1-pentene polymer, and in that case, the content of maleic anhydride is 10% by weight or less. preferable. As the methyl-1-pentene polymer,
Polymers of 4-methyl-1-pentene are preferred.

Next, the liquid saturated hydrocarbon used in the present invention is a paraffin series (methane series) or cycloparaffin series saturated hydrocarbon which is liquid at room temperature and may be a single compound or a mixture. May be. This does not include a polymer of a compound having an unsaturated bond (for example, a polymer of olefin). Saturated hydrocarbons selected from paraffinic and naphthenic process oils, white mineral oils, mineral oils, paraffin waxes and liquid paraffins are preferred. Above all, from the viewpoint of safety and health, the initial boiling point is 149 ° C or higher and the final boiling point is 343 ° C.
The following are preferable. Further, those having no odor and no kerosene odor are preferable. Further, the condition as a wrap film for food, that is, the ultraviolet absorbance (the maximum absorbance per 1 cm of the optical path length) is 280 to 289 nm, 4.0 or less, 290
Those satisfying the conditions of 3.3 or less at 299 nm to 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 by having a layer comprising a resin composition containing the above-mentioned methyl-1-pentene polymer and a liquid saturated hydrocarbon.
In this composition, methyl-1-pentene polymer 9
Liquid saturated hydrocarbon is 1 to 30 parts by weight with respect to 9 to 70 parts by weight, preferably methyl-1-pentene polymer 8
The liquid saturated hydrocarbon is contained in an amount of 5 to 20 parts by weight with respect to 0 to 95 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, and if it exceeds 99 parts by weight, sufficient tackiness cannot be obtained. When the liquid saturated hydrocarbon is less than 1 part by weight, sufficient tackiness cannot be obtained, and when it exceeds 30 parts by weight, it leaches to the film surface and impairs the transparency of the film.

The above composition includes, in addition to the methyl-1-pentene polymer and the liquid saturated hydrocarbon, for example, butene-1 polymer for improving cold resistance; fatty acid amide and fatty acid for facilitating peeling of the film. Bisamide; optional components such as α-methylstyrene / vinyltoluene hydrogenated resin in an amount of 10 parts by weight or less for increasing the tackiness.
In addition, conventional antioxidants, inorganic fillers, antistatic agents,
If necessary, an antifogging agent, an ultraviolet absorber, a coloring agent, a heat resistance stabilizer, a nucleating agent and the like can be included.

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 3 to 50 μm, particularly preferably 10 to 20 μm.

The stretch film of the present invention also has at least one layer comprising the above composition and optionally a layer comprising a propylene-based polymer and / or a layer comprising butene-1 polymer. It can be a multilayer film. When these polymers are contained in the composition, the propylene-based polymer has some excellent heat resistance and is inexpensive, but the transparency of the film is impaired, and the butene-1-based polymer is used. Although it is relatively well compatible with the components of the composition and can give cold resistance, it tends to give the film heat-sealing properties and stick together the films after heating. Therefore, each of these layers is formed without containing these polymers in the composition,
By laminating with the layer made of the composition to form a multilayer, the above-mentioned drawbacks can be eliminated and advantages can be imparted.
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 of the intermediate layer is preferable.

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

[0016]

The present invention will be further described by the following examples. Example 1 Methyl- 1 -pentene polymer (Mitsui Petrochemical Industry Co., Ltd.)
RT-20, 90 parts by weight and liquid paraffin (Esso Petrochemical Co., Ltd., Cristol 352, odorless, initial boiling point)
10 parts by weight (149 ° C, final boiling point: 343 ° C) were supplied to an extruder (Yamaguchi Seisakusho, 40 m / m), melt-kneaded at 280 ° C and 40 rpm, and then a film having a thickness of 15 µm was formed using a T-die. Created. This film was tested as a household wrap film shown below. The results are shown in Table 1. (1) Heat resistance The heat resistant temperature was measured according to the quality labeling method for household products. (2) Adhesiveness The sticking property to the glass container was evaluated by a questionnaire by 10 panelists. The evaluation criteria were as follows: ◎: 9 or more people judged that the adhesiveness was good ○: 7 to 8 people judged that the adhesiveness was good Δ: 4 to 6 people showed the adhesiveness Poor: Poor: 7 or more judged that the tackiness was poor. (3) Film sticking after heating Wrapped 100g chicken fried in film, microwave oven (National NE-M330, high frequency 500W, power consumption 940W)
Sticking of the film comrades after heating for 3 minutes was evaluated by a questionnaire by 10 panelists. The evaluation criteria were as follows: ◎: 9 or more people judged that the sticking was good ○: 7 to 8 people judged that the sticking was good △: 4 to 6 people judged that the sticking was good Poor: 7 or more persons judged that the sticking was bad. (4) Ease of removal from the box A small roll of 20 m long film was placed at 40 ° C for 1
After storing for a week, it was put in a home wrap cosmetics box, and the ease of pulling out was evaluated by a questionnaire by 10 panelists. The evaluation criteria were as follows: ⊚: 9 people or more judged easy to draw ◯: 7 to 8 people judged easy to draw △: 4 to 6 people judged easy to draw ×: Seven or more people judged it difficult to withdraw. (5) FDA Standards It was investigated whether or not it complies with FDA standards (constraints of additives). Example 2 Methyl-1-pentene polymer (Mitsui Petrochemical Industry Co., Ltd.)
Manufactured by RT-20), liquid paraffin (Esso Petrochemical Co., Ltd.)
Manufactured by Cristoll 352) and butene-1 type polymer (manufactured by Mitsui Petrochemical Industry Co., Ltd., Byron M3080) at a ratio of 85 parts by weight, 5 parts by weight and 10 parts by weight, respectively. Melt-knead in the same manner as 1 to give a thickness of 1
A 5 μm film was made. About this film
The same test as in Example 1 was performed. The results are shown in Table 1. Example 3 Propylene polymer sheet (Sumitomo Chemical Co., Ltd.,
Fs-2011D) on both sides with the same composition as in Example 1 (methyl
-1-A composition comprising 90 parts by weight of a pentene polymer and 10 parts by weight of liquid paraffin) is co-extruded and laminated in a layer thickness ratio of 1: 2: 1, and then the laminated body is biaxially stretched. A machine (manufactured by Toyo Seiki Co., Ltd.) was used to draw a film by stretching it 5 times in the length and width. The film thickness was 15 μm.
The same test as in Example 1 was performed on this three-layer film. The results are shown in Table 1. Comparative Example 1 Methyl- 1 -pentene polymer (Mitsui Petrochemical Industry Co., Ltd.)
A film was prepared in the same manner as in Example 1 using only RT-20 manufactured by K.K. The film thickness was 15 μm.
The same test as in Example 1 was performed on this film. The results are shown in Table 1. Comparative Example 2 Methyl-1-pentene polymer (Mitsui Petrochemical Industry Co., Ltd.)
RT-20) 90 parts by weight and liquid polybutene (a polymer whose main component is isobutylene, manufactured by Idemitsu Petrochemical Co., Ltd.,
Melt kneading was performed in the same manner as in Example 1 except that 10 parts by weight of 100 R) was used to prepare a film having a thickness of 15 μm. The same test as in Example 1 was performed on this film. The results are shown in Table 1.

[0017]

[Table 1]

[0018]

EFFECTS OF THE INVENTION The stretch film of the present invention is excellent in heat resistance, has appropriate tackiness, and is easy to handle. Therefore, it is very suitable for use as a household wrap film for heating in a microwave oven. Suitable for Further, since oily foods can be wrapped directly and heated in a microwave oven, the field of cooking using a microwave oven can be expanded.

Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area C08L 23/20

Claims (7)

[Claims] 1. A methyl-1-pentene polymer 99-70.
A stretch film having at least a layer of a composition comprising 1 part by weight and 1 to 30 parts by weight of a liquid saturated hydrocarbon. 2. A methyl-1-pentene polymer is 4-methyl.
-1- The stretch film according to claim 1, which is a pentene polymer. 3. The stretch film according to claim 1, which has a thickness of 5 to 30 μm. 4. The stretch film according to claim 1, wherein the liquid saturated hydrocarbon is selected from paraffinic and naphthenic process oils, white mineral oil, mineral oil, paraffin wax and liquid paraffin. 5. The stretch film according to claim 4, wherein the liquid saturated hydrocarbon is liquid paraffin. 6. The liquid saturated hydrocarbon has an initial boiling point of 149.
The stretch film according to claim 4 or 5, which has a final boiling point of 343 ° C or lower and a boiling point of ℃ or higher. 7. The stretch film according to any one of claims 1 to 6, which is a multilayer film having a layer made of a propylene-based polymer and / or a layer made of a butene-1 type polymer.