JP3242876B2 - Olefin resin multilayer film or sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a flexible multilayer film or sheet made of an olefin resin used for stationery, various cases, packaging, agricultural use, etc.
For details, refer to "Film / Sheet"). For more information, refer to Soft multilayer film made of olefin resin with excellent suitability for high frequency welder, scratch resistance, heat resistance, and cutting property.
It is about a sheet.

[0002]

2. Description of the Related Art Conventionally, flexible films and sheets made of synthetic resin have been used for stationery, various cases, packaging, agricultural use, and the like. Further, as this film / sheet, a single-layer film / sheet made of an ethylene-methyl methacrylate copolymer resin or an ethylene-vinyl acetate copolymer resin is known.

[0003]

The single-layer film / sheet composed of the above-mentioned ethylene-methyl methacrylate copolymer resin or ethylene-vinyl acetate copolymer resin has the advantages of flexibility and excellent suitability for high-frequency welding. In terms of point, it can be said that it is suitable for use in the above applications that often require secondary processing, but on the other hand, it has the disadvantage that the surface is easily scratched (poor in scratch resistance). Various proposals have been made to improve the above, specifically, such as adding a fatty acid amide or forming a coating film on the surface.

[0004] However, in order to improve the scratch resistance by the above-described method, it is difficult to use a high frequency welder which is inherently provided in a film or sheet made of an ethylene-methyl methacrylate copolymer resin or an ethylene-vinyl acetate copolymer resin. In many cases, such characteristics as being excellent in the properties are impaired.

On the other hand, as a technique for solving the above-mentioned problems, as a film / sheet made of an ethylene-methyl methacrylate copolymer resin, the suitability for high-frequency welders inherently possessed by the film / sheet is improved and the surface scratch resistance is improved. It is conceivable to form such an outer layer on both sides of a film or sheet made of an ethylene-methyl methacrylate copolymer resin or the like. Above all, by forming a film / sheet made of an ethylene-methyl methacrylate copolymer resin or the like and an outer layer which can be directly laminated without using an adhesive, it does not impair the high frequency welder suitability and improves the surface scratch resistance. Is one of the preferred methods.

Further, a single-layer film / sheet made of an ethylene-methyl methacrylate copolymer resin or an ethylene-vinyl acetate copolymer resin is inferior in heat resistance and easily deforms even at a temperature of about 80 to 90 ° C. There is also a drawback or a defect that the cutting property is inferior and the blade is hard to enter at the time of cutting, so that the vicinity of the end (the end formed by cutting) is elongated and easily deformed.

As described above, the present invention forms an outer layer which can be directly laminated on a film / sheet made of an ethylene-methyl methacrylate copolymer resin or an ethylene-vinyl acetate copolymer resin without using an adhesive. By improving the scratch resistance of the surface without impairing the suitability of the high-frequency welder that the film or sheet made of an ethylene-methyl methacrylate copolymer resin or the like originally has,
It also improves heat resistance and cutability.

[0008]

According to the present invention, there is provided a film / sheet comprising an intermediate layer made of an olefin resin and an outer layer, wherein the olefin resin forming the intermediate layer is ethylene. The olefin resin mainly composed of at least one selected from (meth) acrylate copolymer resin and ethylene-vinyl acetate copolymer resin, and the olefin resin forming the outer layer is an olefin resin mainly composed of polypropylene. , the olefin resin forming the olefinic resin and / or the outer layer forming the intermediate layer is a high-frequency welder working olefin resin multilayer film sheets, characterized in that hydrogenated rubber is mixed .

The olefin resin forming the intermediate layer of the olefin resin multilayer film / sheet of the present invention is selected from ethylene- (meth) acrylate copolymer resins and ethylene-vinyl acetate copolymer resins as described above. Is an olefin resin mainly composed of a resin or a mixture of two or more selected from these.

The ethylene- (meth) acrylate copolymer resin is obtained by copolymerizing ethylene with an acrylate ester and / or a methacrylate ester. Specifically, the above-mentioned ethylene-methyl methacrylate copolymer resin is used. In addition to the resin, an ethylene-methyl acrylate copolymer resin, an ethylene-ethyl acrylate copolymer resin, and the like can be used.

The ethylene- (meth) acrylate copolymer resin has a (meth) acrylate component content of 5 to 30% by weight, particularly 15 to 30% by weight in view of suitability for a high frequency welder. Is preferred.

Of course, the ethylene- (meth) acrylate copolymer resin may be a mixture of different types of (meth) acrylate and its content, etc., copolymerized with ethylene. . In addition, as long as the properties of the obtained film / sheet are not impaired,
A copolymer of a monomer component other than ethylene and (meth) acrylate may be used.

As the ethylene-vinyl acetate copolymer resin, a resin having a vinyl acetate component of 5 to 30% by weight, particularly 15 to 30% by weight from the viewpoint of suitability for high frequency welding is preferred.

Of course, the ethylene-vinyl acetate copolymer resin may be a mixture of resins having different vinyl acetate contents. Further, as long as the properties of the obtained film / sheet are not impaired, a copolymer of monomer components other than ethylene and vinyl acetate may be used.

If necessary, one or more olefin resins selected from ethylene- (meth) acrylate copolymer resins and ethylene-vinyl acetate copolymer resins constituting the intermediate layer may contain an antistatic agent, an antioxidant, etc. Agents, light stabilizers such as hindered amine compounds, lubricants, ultraviolet absorbers,
Various additives such as an inorganic filler and a coloring agent such as a pigment may be added.

The intermediate layer of the olefin resin multilayer film / sheet of the present invention comprises an ethylene- (meth) acrylate copolymer resin and an ethylene-vinyl acetate copolymer resin to which various additives are added as required. It is formed of one or more selected olefin-based resins. The ethylene- (meth) acrylate copolymer resin and ethylene-vinyl acetate described above may be used as long as the properties of the resulting film or sheet are not impaired. For copolymer resin,
Other polymers, specifically, low density polyethylene,
Polyethylene such as linear low-density polyethylene, medium-density polyethylene, high-density polyethylene; polypropylene (including random and block copolymers of propylene and ethylene, that is, random polypropylene, block polypropylene, etc.); polybutene; olefin-based rubber; ; Etc. may be mixed.

In the multilayer film / sheet made of olefin resin of the present invention, outer layers made of olefin resin are formed on both surfaces of the above-mentioned intermediate layer. As described above, the olefin resin forming the outer layer is an olefin resin mainly composed of polypropylene.

As the above-mentioned polypropylene, homopropylene which is a homopolymer of propylene, random polypropylene which is a random copolymer of propylene and ethylene, block polypropylene which is a block copolymer of propylene and ethylene, and the like can be used. However, from the viewpoint of high-frequency welder suitability, random polypropylene is particularly preferred.

The olefin resin forming the outer layer may include, if necessary, a light stabilizer such as an antistatic agent, an antioxidant, a hindered amine compound, a lubricant, an ultraviolet ray, similarly to the olefin resin forming the intermediate layer. Various additives such as an absorbent, an inorganic filler, and a coloring agent such as a pigment may be added.

As long as the properties of the obtained film / sheet are not impaired, polymers other than the above-mentioned olefinic resins, specifically, low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, Polyethylene such as high density polyethylene; polybutene; olefin rubber; ethylene elastomer;

The multilayer film / sheet made of an olefin resin of the present invention is obtained by mixing a hydrogenated rubber with the olefin resin forming the intermediate layer and / or the olefin resin forming the outer layer. The mixing ratio at this time is 3 to 3 in the total polymer forming each layer.
Desirably, it is about 0% by weight. In this manner, by mixing a hydrogenated rubber with either the olefin-based resin forming the intermediate layer or the olefin-based resin forming the outer layer, or both olefin-based resins, an adhesive is originally interposed therebetween. It is difficult to laminate without doing it,
It is possible to directly laminate an intermediate layer mainly composed of an ethylene- (meth) acrylate copolymer resin or the like and an outer layer mainly composed of polypropylene without using an adhesive.
When it is necessary to further strengthen the interlayer adhesion between the intermediate layer and the outer layer, hydrogenated rubber is mixed with both the olefin resin forming the intermediate layer and the olefin resin forming the outer layer. It is desirable to keep.

The above-mentioned hydrogenated rubber includes styrene-
Hydrogenated rubbers such as butadiene rubber, styrene-isoprene rubber, crystalline olefin / ethylene-butylene / crystalline olefin block copolymer rubber, and styrene / ethylene-butylene / crystalline olefin block copolymer rubber can be used.

The olefin resin multilayer film / sheet of the present invention has an outer layer formed on both surfaces of an intermediate layer, and is preferably formed by a co-extrusion method or a co-extrusion inflation method whose production process is simple. It is. Of course, the intermediate layer and the outer layer are separately formed by means such as a calendering method, an extrusion method, and an inflation method, and the multilayer of the present invention is formed by laminating them by means such as heat lamination or bonding with an appropriate adhesive. A film sheet can be obtained.

The thickness of the olefin-based resin multilayer film / sheet of the present invention is not particularly limited, but is generally in the range of 0.03 to 2.0 m.
m.

In the olefin resin multilayer film / sheet of the present invention, the ratio of the thickness of the intermediate layer to the thickness of each outer layer is preferably in the range of 2: 1 to 20: 1. When the thickness ratio of the intermediate layer and the outer layer deviates significantly from the above range, a multilayer film that can solve the problem of the present invention.
I can't get a sheet. Note that the thickness of both outer layers does not necessarily have to be the same.

The olefin resin multilayer film / sheet of the present invention can form an embossed pattern such as satin or silk on one or both sides, or can form a printed pattern by ordinary printing. In addition, it is also possible to form a coating film of various paints such as water-based, solvent-based, and ultraviolet-curing types.However, the portion where the coating film is formed is significantly reduced in suitability for a high-frequency welder. Need to keep this in mind. Of course, the same applies to the case of forming a print pattern.

The multilayer film / sheet made of the olefin resin of the present invention having the above-mentioned structure is soft, has excellent scratch resistance and heat resistance, does not contain a colorant, or has a small amount of a colorant. (That is, in the case of a colored transparent film or sheet), it is also excellent in transparency. Further, since it is excellent in high frequency welder suitability and cutting property, it is suitable for use in applications requiring secondary processing.

[0028]

EXAMPLES Specific examples of the present invention will be described below, but the present invention is not limited to the following examples.

[Examples 1 to 4, Comparative Examples 1 to 4] Using an olefin resin composition for an intermediate layer and an olefin resin composition for an outer layer having the composition shown in Table 1, the olefin resin composition was used in a three-layer T-die extruder. Extruded to a total thickness of 0.3 mm and a mid layer thickness of 0.3 mm.
An olefin resin multilayer film having a thickness of 25 mm and a thickness of each outer layer of 0.025 mm was obtained. However, in Comparative Examples 1 and 2, the outer layer was not formed, and a single-layer film having a thickness of 0.3 mm was used. The obtained film was evaluated for suitability for high-frequency welder, scratch resistance, transparency, interlayer adhesion, heat resistance, and cutability according to the following criteria.

(A) Suitability for high frequency welder ◎: welding possible without heating the welder blade ○: welding possible by heating the welder blade to 40-60 ° C. △: heating the welder blade to 70 ° C. or more Can be welded ×: High frequency welding is practically impossible (b) Scratch resistance Gakushin type friction tester (Kanakin No.3, 50 rubs)
), The haze value (unit%) was measured based on JIS-K-6714, and compared with the haze value before rubbing. ：: haze value increase of less than 15% ：: haze value increase of 15% or more and less than 20% ×: haze value increase of 20% or more (c) transparency ○: haze value of less than 10% ×: haze value of 10 % Or more (d) Interlayer adhesion 接着: good (no separation between layers of each layer during high frequency welding) ×: poor (separation occurs between each layer during high frequency welding) (e) Heat resistance ：: 100 No deformation is observed even when left at 100 ° C. for 1 hour. ×: Deformation is observed when left at 100 ° C. for 1 hour. (F) Cutability ○: Film edge when 50 films are stacked and cut No deformation of the film is observed. ×: When 50 films are stacked and cut, deformation is observed at the film edge.

[0031]

[Table 1]

In all of the above Examples 1 to 4, no delamination occurred between the layers during welding of the high-frequency welder, and the interlayer adhesion was sufficient. Among them, the hydrogenated rubber was added to both the intermediate layer and the outer layer. Are mixed with the film of Examples 4 to 5 in which hydrogenated rubber is added to only one of the films.
Was superior in the interlayer adhesive strength to the film of the above.

For reference, FIG. 1 shows a partially enlarged cross-sectional view of the olefin resin multilayer film of Example 1. In the drawing, reference numeral 1 denotes an olefin resin multilayer film, reference numeral 11 denotes an intermediate layer, reference numerals 12 (a) and (b) denote outer layers,
Each is shown.

[0034]

As described in detail above, the olefin resin multilayer film / sheet of the present invention is excellent in high-frequency welder suitability, scratch resistance, heat resistance and cutting properties, for stationery, for various cases, for packaging, It can be suitably used for agricultural purposes and the like.

When the amount of the coloring agent is small or when no coloring agent is added, there is an advantage that the transparency is excellent.

Further, the multilayer film / sheet made of an olefin resin of the present invention has excellent interlayer adhesion without interposing an adhesive between the intermediate layer and the outer layer. It can be manufactured.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view of one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Multilayer film made of olefin resin 11 ... Intermediate layer 12 (a), (b) ... Outer layer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (2)

(57) [Claims] 1. An olefin-based resin multilayer film or sheet comprising an olefin-based resin intermediate layer and olefin-based resin outer layers formed on both surfaces thereof, wherein the olefin-based resin forms the intermediate layer. Is an olefin resin mainly composed of at least one selected from ethylene- (meth) acrylate copolymer resin and ethylene-vinyl acetate copolymer resin, and the olefin resin forming the outer layer is mainly composed of polypropylene. A multilayer film or sheet made of an olefin resin for high-frequency welding , wherein the olefin resin is an olefin resin, and the olefin resin forming the intermediate layer and / or the olefin resin forming the outer layer is mixed with a hydrogenated rubber. 2. The thickness ratio between the intermediate layer and the outer layer is 2: 1.
2. The high-frequency welder according to claim 1, wherein the range is from 20 to 20: 1.
-Multilayer film or sheet made of olefin resin for processing .