JPS6116126Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a polyolefin in-laminate material that has both manual tearability in any direction and practical strength.

Paper or metal foil has been used as an excellent packaging material or adhesive tape base because of its excellent shape retention, but it has the drawbacks of low strength and brittleness. Attempts have been made to bond plastic film to paper or metal foil to compensate for this drawback, but since plastic film's molecules are highly oriented, it is strong but loses its ability to be cut by hand. Put it away. Particularly in the case of packaging materials or adhesive tapes, unwrapping after packaging or cutting after adhesion is usually done by hand or with a dispenser, and handling is extremely inconvenient if it cannot be easily cut in any direction. Become. Various attempts have therefore been made to produce plastic films that are easier to cut by hand. For example, methods have been proposed such as stretching plastic film in only one direction, making the film brittle by irradiating it with electron beams, and using materials such as polystyrene, which are inherently brittle. If you do this, you will be able to cut it by hand to some extent. However, a film stretched in one direction can only be cut in one direction, a film made by electron beam irradiation is difficult to balance between practical strength and ease of cutting by hand, and a film made of polystyrene etc. It had the disadvantage that it was too brittle and had no practical strength. Furthermore, even if plastics were obtained that were both easy to cut by hand and strong for practical use, they were difficult to wrinkle or crease, and had the disadvantage of lacking so-called shape retention. Therefore,
In the packaging material industry, there has been a desire for a material that is easy to cut by hand, has practical strength, and has excellent shape retention. The purpose of this invention is to meet the above-mentioned demands,
The object of the present invention is to provide a laminate material that is excellent in manual tearability in any direction, has practical strength, and has excellent shape retention.

That is, in the present invention, the central layer A is a 5-50 μm thick layer made of crystalline low molecular weight polyolefin with an intrinsic viscosity of 0.5-1.5, and a 0.5-8 μm thick layer made of crystalline polyolefin with a higher melting point on both sides.
This polyolefin in-laminate material is characterized in that thin film layers B are laminated, and paper or metal foil C is bonded to one or both sides of the laminated film.

Hereinafter, the present invention will be explained with reference to the drawings.

Figures 1 to 3 show examples of the present invention, and Figure 1 is a package in which a thin film layer B is laminated on both sides of a center layer A, and an aluminum foil layer C is bonded to one side of the layer through an adhesive 1. Similarly, FIG. 2 is a packaging laminate material in which a heat-sealing layer 2 is further laminated on one side of the aluminum foil layer C in FIG. 1, and FIG. 3 is a center layer. Thin film layer B on both sides of A
This is a laminate material for an adhesive tape, in which a layer C' of kraft paper is laminated on one side of the layer C' with an adhesive 1 interposed therebetween, and an adhesive layer 3 and a release paper 4 are further laminated on the other side of layer B.

As for the lamination mode of the present invention, it is sufficient that a layer C of paper or metal foil is laminated on at least one side of a B/A/B type film, and in addition, a heat sealing film, an adhesive, etc. may be laminated or coated.

The crystalline low molecular weight polyolefin used as the center layer A of the laminated film used in the laminate material of the present invention is a copolymer of propylene and other olefins (carbon numbers 2 and 4 to 10) (propylene content 70 to 99.5% by weight). %), copolymers of ethylene and other olefins (3 to 10 carbon atoms) (ethylene content
70-99.5% by weight), copolymers of butene-1 and other olefins (2, 3 and 5-10 carbon atoms) (butene-1 content 70-99.5% by weight), 4-methylpentene-1 and others copolymer with olefin (carbon number 2-10) (4-methylpentene-1 content 70-99.5
olefin copolymers (including not only binary copolymers but also ternary or more copolymers; the copolymerization mode may be either random copolymerization or block copolymerization) such as ,
Ethylene, butene-1,4-methylpentene-1
It is a homopolymer of olefin having 2 to 10 carbon atoms, such as, and has an intrinsic viscosity in the range of 0.5 to 1.5, preferably 0.7.
~1.2. Particularly preferred are the above olefin copolymers having an intrinsic viscosity in the range of 0.5 to 1.5, and even more preferred are:
This is a mixed composition in which the above olefin copolymer having an intrinsic viscosity of 0.5 to 1.5 is mixed with the above olefin homopolymer having an intrinsic viscosity of 0.5 to 1.5 (based on the weight of the mixture, the amount of olefin homopolymer is 2 to 40%).
%). In order to achieve the purpose of the present invention, the intrinsic viscosity of such a crystalline low molecular weight polyolefin must be in the range of 0.5 to 1.5, preferably 0.7 to 1.2. If the intrinsic viscosity is lower than this range, the film will become too brittle and will lack practical strength. Conversely, if the intrinsic viscosity is higher than this range, it will not be easy to cut by hand in any direction. Next, the thickness of the center layer A made of this crystalline low molecular weight polyolefin needs to be in the range of 5 to 50 μm, preferably 10 to 40 μm. If it is thinner than this range, it will lack practical strength and will be too thin, resulting in poor handling and workability. On the other hand, if it is thicker than this range, the ability to cut it by hand in any direction becomes insufficient.

Next, the thin film layer B laminated on both sides of the center layer A will be explained. Thin film layer B is a crystalline polyolefin having a higher melting point than the center layer polymer. The preferable melting point difference between the center layer polymer and the thin film layer polymer is 1
The temperature range is from 50°C to 50°C, more preferably from 5 to 30°C.
The crystalline polyolefin used for this thin film layer B includes propylene, ethylene, butene-1,4-
Methylpentene-1 or other carbon number 10
A homopolymer, copolymer or block copolymer of the following olefins, with an intrinsic viscosity of 0.5~
2.0, preferably in the range of 0.7 to 1.5. The thickness of one sheet of this thin film layer B needs to be in the range of 0.5 to 8 μm, preferably 1 to 5 μm.
If it is thinner than this range, the film will lack practical strength, and if it is thicker than this range, it will not be easy to cut by hand in any direction.

The paper referred to in this invention may be natural paper, synthetic paper, or mixed paper, but kraft paper (both bleached and bleached), white paperboard, roll paper, imitation paper, glassine paper, etc. are easy to use, and usually weigh It is about 50-400g/ ^m2 . Furthermore, the metal foil referred to in the present invention is a foil made of any metal (including alloys) such as aluminum, tin, zinc, steel, silver, etc., and usually has a thickness in the range of 5 to 50 microns. The most commonly used is aluminum foil around 10 microns thick. These metal foils are often subjected to some kind of surface treatment (such as anchor coating or physical roughening) to improve adhesion.

The adhesive used to bond the metal foil or paper to the laminated film is not particularly limited, and any adhesive that can be used as a laminating adhesive can be used. However, the simplest and most economically advantageous method is to melt extrude polyethylene and use it as an adhesive.

The range in which the present invention has both hand cutability in any direction and practical strength, which is one of the objectives of the present invention, can be well expressed by the falling ball impact strength of the laminated film laminated to the present laminated material. In other words, in order to have the ability to cut by hand in any direction, the thickness of the film must be within the range of 6 to 66 μm, preferably 12 to 50 μm.
Within the thickness range of μm, this falling ball impact strength is
It is highly desirable that it be less than 25 Kg.cm, preferably 20 Kg.cm. Conversely, in order to have practical strength, the falling ball impact strength must be 2 kg cm or more.
Preferably, it is extremely desirable that the weight is 5 kg/cm or more. Therefore, in terms of numerical values, the ability to cut by hand in any direction and practical strength means that the impact strength of a falling ball should be 2 to 25 kg/cm, preferably 5 to 20 kg/cm.
It can also be described as a three-layer laminated polyolefin film with values in the cm range.

Next, a general example of the method for manufacturing the laminate material of the present invention will be described. First, a three-layer laminate sheet in the form of B/A/B is produced by a known coextrusion method, with a crystalline low molecular weight polyolefin as layer A and a crystalline polyolefin with a higher melting point as layer B. In this case, the intrinsic viscosity of the A layer polymer after film production is 0.5 to 2.0, preferably 0.7 to 2.0.
Use something that falls within the range of 1.2. Also,
The intrinsic viscosity of the B layer polymer is such that the intrinsic viscosity of the B layer after film production is 0.5 to 2.0, preferably 0.7 to 1.5.
Use something that falls within the range. In order to facilitate coextrusion, etc., it is desirable that the intrinsic viscosity of layer B be within the above range, within ±20%, preferably within ±10%, of the intrinsic viscosity of layer A.
The thicknesses of layer A and layer B of this three-layer laminated sheet are:
The thickness of layer A after film production is 5 to 50 μm,
The thickness of layer B is preferably in the range of 10 to 40 μm, and the thickness of layer B is 0.5 to 8 μm, preferably 1 to 5 μm.
It should be within the μm range. Further, the melting point of the polymer in the B layer is set to be 1 to 50°C, preferably 5 to 30°C higher than that of the A layer.

Such a three-layer laminated sheet is biaxially stretched 1.5 to 15 times, preferably 2 to 10 times, in the longitudinal direction and the axial direction by a known biaxial stretching method such as simultaneous biaxial stretching or sequential biaxial stretching. do. The stretching temperature at this time is preferably in the range of (melting point of layer A polymer - 10) C. or higher and lower than or equal to the melting point of layer B polymer. Next, this biaxially stretched film is heat-treated for 1 to 100 seconds, preferably for 3 to 30 seconds, at a temperature that is higher than the melting point of the A-layer polymer and lower than the melting point of the B-layer polymer. This heat treatment may be a tension heat treatment in which the film is kept under tension, or a relaxation heat treatment in which the film is allowed to relax by 1 to 20% of its original length in the longitudinal and/or width directions; A combination of these may also be used. Next, if necessary, one or both sides of this film are subjected to a known surface activation treatment such as corona discharge treatment to increase the wetting tension of the treated surface to 35 to 50 dynes/cm.
shall be. The three-layer laminated film thus obtained is
The thickness of layer A is 5 to 50 μm, preferably 10 to 40 μm
and the thickness of the B layer is 0.5 to 8 μm,
Preferably, the thickness is in the range of 1 to 5 μm, and the total thickness is in the range of 6 to 66 μm, preferably 12 to 50 μm.

Next, aluminum foil C and this film are made to face each other, and polyethylene is melt-extruded between them to bond the film and aluminum foil together.
Finally, by melt-extrusion laminating polyethylene as a heat-sealing layer on the surface of the aluminum foil, the packaging laminate material of the present invention having a cross-sectional structure as shown in FIG. 2 can be obtained.

The laminated material of the present invention has the following advantages.

(1) Since the base polyolefin film itself is easy to cut by hand and has practical strength, it becomes a laminate material that is easy to cut and has practical strength.

(2) When paper is laminated, it has good shape retention and printability, and is advantageous for packaging.

(3) When laminating metal foil, shape retention,
It has good moisture resistance and a beautiful surface, making it highly useful for packaging and tape.

[Brief explanation of the drawing]

Figures 1 to 3 show examples of the present invention, Figure 1 is a packaging laminate material laminated with aluminum foil, Figure 2 is a heat-sealable packaging laminate material laminated with aluminum foil, and Figure 3 is paper. FIG. 3 is a schematic cross-sectional view of a laminate material for adhesive tape laminated with . 1... Adhesive, 2... Heat seal layer, 3...
Adhesive layer, 4... Release paper, A... Center layer, B... Thin film layer.

Claims (1)

[Scope of utility model registration request] The central layer A is a 5 to 50 μm thick layer made of crystalline low molecular weight polyolefin with an intrinsic viscosity of 0.5 to 1.5, and thin film layers B of 0.5 to 8 μm thick made of crystalline polyolefin with a higher melting point are laminated on both sides. A polyolefin in-laminate material characterized in that the laminated film is further laminated with paper or metal foil C on one or both sides thereof.