JPH02265745A - Laminated film or sheet and carton manufactured thereof - Google Patents

Abstract

PURPOSE:To obtain a laminated sheet for container raw material preventing completely permeation of oil and fat ingredients from a contained cooked food by forming it from three layers consisting of a layer made of a high m.p. poly-4- methyl-1-pentene, an intermediate layer made of a low temp. poly-4- methyl-1-pentene and a layer made of a paper. CONSTITUTION:A high m.p. poly-4-methyl-1-pentene constituting one layer of a laminated sheet has a m.p. of 220-245 deg.C and a low m.p. poly-4-methyl-1-pentene constituting an intermediate layer has a m.p. of 190-230 deg.C. In addition, as a paper constituting one more layer, a clay-coated paper, etc., is used. A laminated sheet is prepd. by extrusion-coating the paper with two kinds of poly-4- methyl-1-pentene constituting an intermediate layer and one more layer by means of a coextrusion. A carton prepd. from this type of a laminated sheet exhibits excellent oil resistance and is suitable used as tray for cooking by using an electronic range and as a packaging container for foods contg. oils and fats ingredients such as cakes and cake breads.

Description

Detailed Description of the Invention (Technical Field of A) The present invention relates to a laminated film or sheet formed by laminating a layer made of a specific resin and a layer of paper, and a carton made from the same. In particular, the present invention relates to a film or sheet having excellent oil and fat impermeability, consisting of two types of poly-4-methyl-1-pentene layers and paper, and a carton made from the same.

(Conventional technology and its problems) Recently, cooking methods using microwave ovens have rapidly progressed and become popular.
It has become extremely easy to prepare a wide variety of foods such as dishes and sweets.

When cooking food in the microwave, for example, 4-methyl-
Food for cooking is stored in a tray-shaped container formed from a laminated sheet of an inner layer made of a 1-pentene polymer and an outer layer made of paper, and then heated using high frequency waves.

Some of the above-mentioned foods include, for example, those that contain oil and fat components such as butter and margarine, such as bound cakes, and those that contain oil and fat components such as hamburgers, which are heated in a microwave oven and then cooked with a sauce containing oil and fat components. However, 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 oil and fat components.

In such cases, over time, the oil and fat components penetrate into the paper layer constituting the container, causing the entire paper layer to become oily and paper-like, impairing the appearance of the container, and causing damage to the container during handling.
Your hands and clothes may become contaminated with oil and fat components.

(Object of the Invention) Therefore, an object of the present invention is to provide a laminated 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 made to achieve the above object, and includes a layer (
A), a layer made of poly-4-methyl-1-pentene with a low melting point (B) as an intermediate layer, and a layer made of paper (C), which is a laminated sheet consisting of at least three layers. It is something to do.

High melting point poly(4-) constituting one layer of the laminated sheet
Methyl-1-pentene has a melting point of 220 to 245°C, and low melting point poly-4-methyl-1-pentene constituting the intermediate layer has a melting point of 190 to 230°C.

(Description of preferred embodiments) In the present invention, the high melting point poly-4-methyl-1-pentene is a homopolymer of 4-methyl-1-pentene or 4-methyl-1-pentene, usually 20% by mole. Below, preferably 12 mol% or less of other α-olefins, such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-tetradecene, 1
- A crystalline poly(4-methyl) copolymer with an α-olefin having 2 to 20 carbon atoms such as octadecene and having a melting point of 220 to 245°C, preferably 225 to 240°C.
1-Pentene is preferably used, and this polymer can be produced by methods known per se, for example the method described in JP-A-59-206418. The MFR of high melting point poly 4-methyl-1-pentene is 5 to ioo
.

Although 8,710 g/10 min is preferable, 70 to 300 g/10 min is particularly preferred since it has good moldability and heat resistance.

Furthermore, the MFR of the low melting point poly-4-methyl-1-pentene in the present invention is
Same as pentene, but the melting point is 190 to 230℃
, preferably from Zoo to 230°C, and this polymer can also be polymerized by the method described in JP-A-59-206418. At this time, the copolymerization amount of α-olefin is increased. By increasing the melting point above that of poly-4-methyl-1-pentene, polymers having the above-mentioned melting point range can be obtained.

Generally, the melting point decreases as the amount of copolymerized α-olefin increases, but it is also influenced by factors such as the type of α-olefin, the catalyst used, and other polymerization conditions. However, since the relationship between these factors and melting point can be determined experimentally in advance, it is easy for those skilled in the art to obtain poly-4-methyl-1-pentene having the intended melting point.

As mentioned above, the high-melting point poly-4-methyl-1-pentene and the low-melting point poly-4-methyl-1-pentene in the present invention have different melting points, and their melting point ranges partially overlap. However, high melting point poly-4-methyl-1
- It is necessary to use a pentene having a melting point higher than that of the low melting point poly-4-methyl-1-pentene forming the intermediate layer.

In this way, by forming one layer of high-rigidity poly-4-methyl-1-pentene with a high melting point and using a layer of low-rigidity poly-4-methyl-1-pentene with a lower melting point as an intermediate layer, Even when both layers are heated in a microwave oven, the oil and fat components do not penetrate into the paper layer provided as another layer, making it possible to provide a laminated sheet suitable as a container material.

In addition, as the paper constituting the other layer, clay coat paper, milk carton paper, etc., which are usually used as box-making materials, are used.
- Even if pinholes or very small cracks appear in the two layers made of pentene due to external impact or abrasion, or if the above-mentioned oil and fat components penetrate from the edge of the laminated sheet. It is recommended to use clay coated paper because the penetration of oil and fat components is extremely slow, and since this clay coated paper has excellent printability, it is possible to form a printing layer on the outer surface of the container as necessary. It also serves as a suitable printing base material.

The laminated sheet of the present invention can be produced by directly extrusion-coating two types of poly-4-methyl-1-pentene constituting the intermediate layer and another layer on paper, or by directly extrusion coating the paper and the intermediate layer. In order to further increase the adhesive strength of the paper, an anchor coating agent such as organic titanium, polyethylenemine, or isocyanate may be coated on the surface of the paper in advance using a known method, or an adhesive polyolefin, high-pressure polyethylene, etc. may be coated on the paper surface. Extrusion coating may be performed after priming.

In the present invention, poly-4-methyl-1-pentene, which constitutes the inner layer and the intermediate layer, has excellent extrusion coating properties at high speeds, so it can be coated at high speeds using ordinary coextrusion coating processing equipment. Extrusion coating is possible, and a laminated sheet with excellent mechanical properties and interlayer adhesion can be obtained. However, when extrusion coating is applied, gas such as air or nitrogen gas is exposed to both ends of the film. By spraying
Neck-in and ear shaking at both ends of the film-like material can be improved; in this case, preferably, gas is blown 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. By doing so, extrusion coating at high speeds with stable layers can be achieved.

Specifically, as a method for blowing gas onto a film-like material, a conduit such as a metal pipe such as an aluminum pipe, a steel pipe, or a thermoplastic resin pipe is placed downstream of the die, and the gas is blown from the conduit through the poly-4-methyl- A method may be mentioned in which the 1-pentene film is extruded from a die and sprayed at any position between which it contacts the substrate, preferably near the contact point where the film is coated on the substrate. The pressure of the gas at the time of spraying is determined as appropriate in consideration of the thickness of the film material to be coated, but is usually in the range of 0.5 to 5 kg/cm'G. The aperture of the tip of the spraying nozzle is usually in the range of 111,112 to 50 m2, preferably 5 m2 to 10 m2. Also, the distance from the tip of the nozzle to the film-like material is usually 21cm to 100m5. Preferably 5IllI
It ranges from 1+ to 20+1. Furthermore, it is preferable to direct the tip of the spray nozzle from the inside to the outside of the film-like material because the blown gas expands the film-like material and further increases the effect of narrowing the neck-in.

In the present invention, the extrusion temperature when extrusion coating the two types of poly4-methyl-1-pentene constituting the inner layer and the intermediate layer on the base material is usually 250 to 370°C, preferably 250°C to 370°C, preferably 250 to 370°C.
It can be carried out at 90 to 340°C. The extrusion coating speed (coating material take-off speed) may be 100 m/win or more, preferably 150 to 500 m/win. The film thickness of the high-melting point poly-4-methyl-1-pentene layer/low-melting point poly-4-methyl-1-pentene layer/paper in the laminated sheet can be selected arbitrarily, but is usually 1 to 20 mm.
00μm/1 to 2000um15 to 5000μm, preferably 5 to 50μm15 to 50μm
A range of m/Zoo to 600 μm is used.

The poly-4-methyl-1-pentene used in the present invention includes:
Compounding agents known per se such as weathering stabilizers, heat stabilizers, antistatic agents, antifogging agents, antiblocking agents, slip agents, and coloring agents can be added within a range that does not impair the purpose of the present invention.

(Effects of the Invention) According to the present invention, by forming a laminate sheet consisting of a high melting point poly-4-methyl-1-pentene layer/low melting point poly-4-methyl-1-pentene layer/paper layer, a high melting point poly 4
- Penetration of oil and fat components from the methyl-1-pentene layer side is completely prevented, and cartons made from this laminated sheet exhibit excellent oil resistance, so they can be used as trays for cooking in microwave ovens. It can also be suitably used as a packaging container for foods containing oil and fat components, such as cakes and sweet breads.

(Example) The present invention will be described in detail below based on examples.

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

The melting point in the present invention is determined using a differential scanning calorimeter (Model
DSC-11 (manufactured by Birkin Elmer), the sample was melted at 260°C for 5 minutes, cooled to room temperature at a rate of 20°C/min, crystallized, kept at room temperature for 1 minute, and then melted at 10°C/wi.
0 is the peak temperature when the endothermic curve is measured at a heating rate of n. Poly4-methyl-1-pentene used in the present invention may have one or more endothermic peaks; The highest peak temperature is taken as the melting point.

MFR: Measured at 260° C. under a load of 5 g according to ASTM D 1238.

Initial bending modulus: Measured according to ASTM D 790. (However, the test speed was 5 m/min.) Melting point 237°C, MFR 180g/1011in, initial bending modulus 13. 4-methyl-1 in OQOKg/cm'
- a crystalline copolymer of pentene and 1-decene (1-decene content 2.swt9g) (hereinafter referred to as PMP (1)), melting point 226°C, MFR 26g/l 0mln,
A crystalline copolymer of 4-methyl-1-pentene and 1-octadecene (1-octadecene content: 6 wt%) with an initial bending modulus of 5,000 Kg/cIQ2 (hereinafter referred to as PMP (II)
) were each melted in an extruder with a diameter of 65 mm, and laminated onto milk carton paper with a basis weight of 290 g/10 w1n using a coextrusion two-layer die. The total coat thickness was 30μ with each layer being 15μ. 10cm x 1 of the obtained laminated paper so that the inner surface becomes a coating layer
A box of 0cm x 5cm (depth) was made.

Weigh 40g of commercially available margarine (manufactured by Snow Brand Milk Products), put it in a box, and microwave it (Matsushita Electric Industrial; Type NE-A).
Heat at 740 for 30 seconds. After heating, the paper was left at room temperature, and the number of days until margarine oozed out to the outer surface of the paper layer was visually determined.

Also, using the same box as above, a thick layer of Chicolate Cake (House Range Gourmet, House Foods) and water 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) 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.

Melting point 22 instead of PMP (II) used in Example 1
Crystalline copolymer of 4-methyl-1-pentene and octadecene (octadecene content 4
The procedure was carried out in the same manner as in Example 1, except that PMP (III) (hereinafter referred to as PMP (III)) was used. The results are shown in Table 1.

Example 1 was carried out in the same manner as in Example 1, except that PMP (I) used in Example 1 was used in both layers of the two coextruded layers.

The results are shown in Table 1.

Salt I''LL A single layer die was used instead of the coextrusion two layer die used in Example 1 to laminate PMP (I) to a coating thickness of 15μ. While opening the rolled up semi-finished product roll, 15μ of PMP (1) was coated again to obtain a product with a total coating thickness of 30μ.

Table 1 shows the results of the same exudation last as in Example 1.

Claims (5)

[Claims] (1) A layer (A) made of poly-4-methyl-1-pentene with a high melting point, an intermediate layer (B) made of poly-4-methyl-1-pentene with a lower melting point, and a layer made of paper (C) A laminated film or sheet composed of. (2) Claim (1) wherein the melting point of the high melting point poly-4-methyl-1-pentene of the layer (A) is 220 to 245°C.
The laminated film or sheet described above. (3) The laminate according to claim (1), wherein the intermediate layer (B) is made of poly-4-methyl-1-pentene having a low melting point of 190 to 230°C. film or sheet. (4) The thickness (A)/(B)/(C) of each layer constituting the laminated film or sheet is 1 to 2000 μm/1
Claims (15 to 5000 μm)
1) The laminated film or sheet described above. (5) A carton made from the laminated sheet according to claim (1).