JPH02274535A - Laminate film or sheet and carton formed thereof - Google Patents

Abstract

PURPOSE:To enhance imperviousness to oils and fats by providing an intermediate layer of a propylene polymer and a paper layer on a poly-4-methyl-1-pentene layer to form a three-layer film or sheet. CONSTITUTION:An intermediate layer of a propylene polymer is provided on a layer of poly 4-methyl-1-pentene, and a layer of paper is provided on the intermediate layer to form a laminate film or sheet having at least three layers. The poly-4-methyl-1-pentene layer is preferably formed of a poly-4- methyl-1-pentene which has a melting point of 190 to 245 deg.C, and the intermediate layer is preferably formed of a polypropylene having an MFR of 1 to 200g/10min. Cartons formed of the laminate sheet thus obtained have excellent oil resistance, and are useful as cartons for oil- or fat-containing foodstuffs.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a laminated film or sheet formed by laminating a plurality of layers made of a specific resin and a layer of paper, and a carton made from the same. More specifically, a laminated film or sheet having at least a three-layer structure made of poly4-methyl-1-pentene/propylene polymer/paper, and a carton made from the same with excellent oil and fat impermeability. Regarding.

(Conventional technology and its problems) Recently, cooking methods using microwave ovens have rapidly progressed and become popular.
It has become extremely easy to cook foods such as 5-scale dishes and sweets.

When cooking food in the microwave, for example, 4-methyl-
Food to be cooked is stored in a tray-shaped container formed from a laminated sheet made of paper and an inner layer made of a 1-pentene polymer, and heated using high frequency waves. Among the above foods,
For example, there are products such as bound cakes that contain fats and oils such as butter and margarine, and products such as hamburgers that are heated in a microwave oven and then covered with a sauce containing fats and oils. In some cases, the food is stored in a box-like container after being heated in a microwave oven or after being covered with a sauce containing an oil or fat component.

In such cases, over time, the oil and fat components penetrate into the paper layer constituting the container, and the entire paper layer becomes like oily paper, which impairs the appearance of the container and also makes it difficult to handle with your hands or fingers. Clothing may become soiled with oil and fat components.

(Object of the Invention) Therefore, an object of the present invention is to provide a laminated film or sheet that can be used as a container material that can completely prevent penetration of oil and fat components from stored cooked foods.

(Means for Solving the Problems) The present invention has been proposed to achieve the above object, and includes a layer made of poly4-methyl-1-pentene as a layer, and a layer made of a propylene polymer as an intermediate layer. The sheet is characterized by being a laminate sheet consisting of at least three layers, including a layer made of paper and another layer made of paper.

In the laminated sheet of the present invention, the melting point of poly4-methyl-1-pentene constituting the inner layer is usually 200 to 245°C, preferably 220 to 235°C, and the propylene polymer constituting the intermediate layer is MFR is 1 to 200g7
A homopolymer of propylene or a random copolymer with ethylene of 10 min, preferably 10 to 100 min.

(Description of preferred embodiments) In the present invention, poly-4-methyl-1-
Pentene is a homopolymer of 4-methyl-1-pentene, or 4-methyl-1-pentene and other α-olefins, usually 20 mol% or less, preferably 12 mol% or less, such as ethylene, propylene, 1-butene, 1
-hexene, 1-octene, 1-decene,! - A copolymer with an α-olefin having 2 to 2 carbon atoms such as tetradecene or 1-octadecene, and has a melting point of 200 to 24
A temperature of 5°C, preferably 220 to 235°C is suitably used.
Polymerization can be carried out by the method described in Japanese Patent No. 18.

Moreover, the MFR of poly4-methyl-1-pentene is 0.5
Those with a ratio of 20 to 1000 g/10 minutes are preferably used, and among them, those with a ratio of 20 to 300 g/10 minutes are particularly preferably used because they do not cause melt fracture and can be easily extruded. I can do it.

In the present invention, the propylene-based polymer forming the intermediate layer is usually a crystalline homopolymer of propylene with an MFR of 1 to 200 g710 min, preferably 10 to 100 g710 min, or propylene and other materials, usually 15 mol% or less. It means a crystalline copolymer of α-olefin such as ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, etc.

Furthermore, as the paper constituting the outer layer, clay coat paper, milk carton paper, kraft paper, etc., which are usually used as box-making materials, are used. Even if pinholes or very small cracks appear in the intermediate layer formed by the combination due to external impact or abrasion, or if the above-mentioned oil and fat components penetrate from the end surfaces of the laminated sheet, the oil and fat It is recommended to use clay-coated paper because the penetration of ingredients is extremely small, and this clay-coated paper has excellent printability, so a printing layer can be formed on the outer surface of the carton as necessary. It also serves as a suitable printing base material.

The laminated sheet of the present invention has poly4-methyl-1 on paper.
- direct extrusion coating of pentene and the propylene polymer forming the intermediate layer by coextrusion, or coating the surface of the paper in advance by a method known per se in order to further increase the adhesive strength between the paper and the intermediate layer; For example, an organic titanium-based, polyethyleneimine-based, or isocyanate-based anchor coating agent may be applied, or an adhesive polyolefin or high-pressure polyethylene may be applied and then extrusion coated. In this case, four layers may be applied. This constitutes a laminated sheet consisting of:

In the present invention, the poly-4-methyl-1-pentene and propylene polymers constituting the outer layer and the intermediate layer both have excellent extrusion coating properties at high speeds.
Extrusion coating can be carried out at high speeds using ordinary coextrusion coating processing equipment, and a laminated sheet with excellent mechanical properties and interlayer adhesion can be obtained. By blowing a gas such as air or nitrogen gas on both ends of the film-like material, neck-in and ear shaking at both ends of the film-like material can be improved.
Preferably, by blowing gas from the side where the film-like material does not contact the base material in the vicinity where the film-like material contacts the base material, extrusion coating can be achieved at high speed with a stable layer. .

Specifically, as a method for blowing gas onto a film-like material, for example, a conduit such as a metal pipe such as an aluminum pipe, a steel pipe, or a thermoplastic resin pipe is placed downstream of a die, and the gas is coextruded from the conduit to produce a film-like material. Examples include a method in which the material is sprayed at any position between the product being extruded from the die and contacting the base material, preferably near the contact point where the film-like material is coated on the base material. The pressure of the gas when spraying is determined as appropriate considering the thickness of the film-like material to be coated, but it is usually 0.5 to 5.
It is in the range of KH/cm'G. The aperture of the tip of the spray nozzle is usually in the range of 1 mm" to 50 mm, preferably 5 in" to 10 mm2.The distance from the tip of the nozzle to the film-like material is usually 2 mm.
II11! 001101. Preferably 511II
The range is from 1+ to 20 ram. Furthermore, it is preferable to point the tip of the nozzle from the inside of the film-like material toward the outside, since the blown gas expands the film-like material and further increases the effect of narrowing the neck-in.

The extrusion temperature when extrusion coating the poly-4-methyl-1-pentene and propylene polymer of the present invention on a base material is usually 25
It can be carried out at a temperature of 0 to 370°C, preferably 290 to 340°C. Also, the extrusion coating speed (coating material take-off speed) is t
OOm/+++in or more, even 150 to 500m
/l1lin. The thickness of the poly4-methyl-l-bentene layer/propylene polymer layer/paper in the laminated sheet can be selected arbitrarily, but is usually 1.
~2 GOOμm/1~2000/J m
/5 to 5000 μm, preferably 5
~5C14m, 5~50μrn/100~600
A range of μm is used.

The poly-4-methyl-1-pentene and propylene polymers used in the present invention may each include known weather stabilizers, heat stabilizers, antistatic agents, and preventive agents within the range that does not impair the purpose of the present invention. Compounding agents such as fogging agents, anti-blocking agents, slip agents, and coloring agents can be added.

(Effects of the Invention) According to the present invention, by forming a laminated sheet consisting of a poly-4-methyl-1-pentene layer/a propylene polymer layer and seven paper layers, an oil and fat component is added to the poly-4-methyl-1-pentene layer. Cartons made from this laminated sheet have excellent oil resistance, so they can be used as trays for cooking in microwave ovens, as well as for cakes, pastries, etc. It can be suitably used as a packaging container such as a carton for foods containing oil and fat components.

(Example) Hereinafter, the present invention will be described in detail based on examples.

In the following examples, the melting point and MFR1 initial bending modulus were measured by the following methods.

The melting point in the present invention is determined using a differential scanning calorimeter (Model
Using DS (: -II: manufactured by Birkin Elmer), the sample was melted at 260°C for 5 minutes, then cooled to room temperature at a rate of 20°C/min to crystallize, and kept at room temperature for 1 minute.
10℃/! This is the peak temperature when an endothermic curve is measured at a heating rate of 1 lin. Poly-4-methyl-1-pentene used in the present invention may have one or more endothermic peaks, in which case the highest peak temperature is taken as the melting point.

MFR of poly-4-methyl-1-pentene: Measured at 260° C. under a load of 5 g according to ASTM D 1238.

Initial bending modulus: ASTM D 790 test speed 5
Measured in mm/min.

MFR of polypropylene: ASTM D 1238
Load 2,16 g, 230°C Example 1° Melting point 236°C, MFRl 80g/l 0mln.

(260℃, 5g load), initial bending modulus 13,00
0 to 37 cm” of poly-4-methyl-1-pentene and 1-
Crystalline copolymer with decene (1-decene content 2.5 w
t%) (hereinafter referred to as PMP (1)) and MFR30g
/ 10 m1n (210°C, 2.13g load) of propylene homopolymer (hereinafter referred to as pp(1)),
Each was melted using an extruder with a diameter of 65 mm, and laminated onto milk carton paper with a basis weight of 290 g/10 a+in using a two-layer coextrusion die. The total coat thickness was 30μ with each layer being 15μ. The obtained laminated paper is 10cm x 10cm so that the inner surface becomes a coating layer.
I made a box with m x 5 cm (depth).

Next, 40 g of commercially available margarine (manufactured by Snow Brand Milk Products) was weighed and put into the above box, and heated for 30 seconds in a microwave oven (Matsushita Electric Industrial; type NE-A740). After heating, it was left at room temperature, and the number of days until margarine oozed out to the outer surface of the paper side was visually determined.

Also, using the same box as above, raw flour and water for chocolate cake (House Range Gourmet, House Foods) were added, and the mixture was cooked in the same microwave oven for 3 minutes and 30 seconds.

After cooking, the contents were observed to see if they oozed out to the outside without removing them.

Using the same box as above, add butter cake (House Range Gourmet, House Foods) flour and water and heat in the oven for 19 minutes.
Cooked for 20 minutes at a set temperature of 0°C. After cooking, the contents were observed to see if they oozed out to the outside without removing them.

The results are shown in Table 1.

Example 2゜The coating thickness of PMP (I) used in Example 1 was 10 μm.
The same procedure as in Example 1 was conducted except that the coating thickness of PP(1) was 20 μm. The results are shown in Table 1.

Example 3゜In place of PP (I) used in Example 1, ethylene-propylene random copolymer (ethylene content 4 wt.
%) (hereinafter referred to as PP(■)) was carried out in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1゜In place of PP(I) used in Example 1, PMP (1
) and pp(t) in a ratio of 3:1 was used.

The results are shown in Table 1.

Comparative Example 2゜In place of PP(I) used in Example 1, PMP(1)
A product with a total coating thickness of 30 μm was obtained by carrying out the same procedure as in Example 1 except that a resin containing a mixture of PP(I) and PP(I) at a ratio of 1=1 was used.

Table 1 shows the results of the same seepage test as in Example 1.

Comparative Example 3゜A single-layer die was used in place of the coextrusion two-layer die used in Example 1, and PMP (I) was laminated with a coating thickness of 15 μm. Then, PMP (1) was laminated again with a coating thickness of 15μ to obtain a product with a total coating thickness of 30μ. This product was also subjected to the same bleeding test as in Example 1, and the results are shown in Table 1.

Claims (4)

[Claims] (1) Layer (A) consisting of poly4-methyl-1-pentene
A laminated film or sheet comprising at least three layers: an intermediate layer (B) made of a propylene polymer, and a layer (C) made of paper. (2) The poly4-methyl-1-pentene layer has a melting point of 1
The laminated film or sheet according to claim 1, which is made of poly-4-methyl-1-pentene at a temperature of 90 to 245°C. (3) The laminated film or sheet according to claim (1), wherein the intermediate layer is a polypropylene layer having an MFR of 1 to 200 g/10 minutes. (4) A carton made from the laminated film or sheet according to claim (1).