JPH11188822A - Multi-layer film or sheet made of olefinic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve resistance to scratching and heat, and cutting characteristics of an ethylene-methyl methacrylate copolymer resin film or sheet without deteriorating characteristics such as excellent high-frequency welder ability or the like. SOLUTION: An interlayer 11 is formed of an olefinic resin having a main component composed of one or more kinds selected from an ethylene-(meth) acrylic ester copolymer, ethylene-vinyl acetate copolymer resin, where outer layers 12a and 12b, which have a main component composed of sindiotactic polypropylene, or a mixture composed of the sindiotactic polypropylene and one or more kinds selected form the ethylene-vinyl acetate copolymer resin and ethylene-(meth)acrylic ester copolymer, are formed on both sides of the interlayer 11 to obtain an olefinic resin multilayer film 1 or sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flexible multilayer film or sheet (hereinafter referred to as "film / sheet") made of an olefin resin used for stationery, various cases, packaging, agricultural use, and the like. Sometimes)
More specifically, the present invention relates to a flexible multilayer film / sheet made of an olefin resin having excellent suitability for high-frequency welding, excellent scratch resistance, heat resistance, and cutting properties.

[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 a defect that the surface is easily scratched (poor in scratch resistance),
Conventionally, various proposals have been made to improve this, specifically, proposals such as adding a fatty acid amide and forming a coating film on the surface have been made.

[0004] However, in order to improve the scratch resistance by the above-described method, it has been found that the film / sheet made of an ethylene-methyl methacrylate copolymer resin or an ethylene-vinyl acetate copolymer resin has an inherent high frequency welder. In many cases, such characteristics as being excellent are impaired.

Further, a single-layer film or sheet made of an ethylene-methyl methacrylate copolymer resin or an ethylene-vinyl acetate copolymer resin is inferior in heat resistance, and tends to be deformed 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.

[0006] The present invention provides a film / sheet made of an ethylene-methyl methacrylate copolymer resin, an ethylene-vinyl acetate copolymer resin, or the like, which has improved scratch resistance, heat resistance, and cutting property without impairing the inherent properties of the film / sheet. It is to improve disadvantages such as inferiority.

[0007]

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. -An olefin resin mainly composed of at least one selected from (meth) acrylate copolymer resins and ethylene-vinyl acetate copolymer resins, wherein the olefin resin forming the outer layer is (a) syndiotactic polypropylene; Olefin resin mainly composed of (a) syndiotactic polypropylene and olefin resin mainly composed of a mixture of at least one selected from ethylene- (meth) acrylate copolymer and ethylene-vinyl acetate copolymer resin It is a multilayer film or sheet made of an olefin-based resin, characterized in that

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 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 of 5 to 30% by weight, particularly 15 to 30% by weight from the viewpoint 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 monomer component other than ethylene and vinyl acetate may be copolymerized.

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 have an antistatic agent, an antioxidant, 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. Polymers other than copolymer resins, specifically, low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, polyethylene such as high-density polyethylene; isotactic or syndiotactic polypropylene (random of propylene and ethylene, Block copolymers, ie random polypropylene, block poly Including such propylene); polybutene; olefin rubbers, ethylene-based elastomer; like no problem even by mixing.

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 composed of (a) an olefin resin mainly composed of syndiotactic polypropylene, (a) a syndiotactic polypropylene, an ethylene- (meth) acrylate copolymer resin and ethylene. An olefin resin mainly composed of a mixture with at least one selected from vinyl acetate copolymer resins.

The syndiotactic polypropylene forming the outer layer is obtained, for example, by polymerization using a metallocene catalyst. In addition, as long as its properties are not impaired, it may be copolymerized with other monomers such as ethylene.

Further, as the olefin resin forming the outer layer, the olefin resin (a) described above, that is, syndiotactic polypropylene, ethylene- (meth)
When using an olefin resin mainly containing a mixture with at least one selected from an acrylate copolymer resin and an ethylene-vinyl acetate copolymer resin, ethylene- (meth) acrylate copolymer mixed with syndiotactic polypropylene The mixing ratio of the resin and the like is preferably 50% by weight or less, and particularly preferably 20% by weight or less from the viewpoint of scratch resistance.

When the olefin resin of the above (a) is used as the olefin resin forming the outer layer,
As the (meth) acrylate copolymer resin and ethylene-vinyl acetate copolymer resin, the above-mentioned ethylene- (meth) acrylate copolymer resin forming the intermediate layer,
The same ones as the ethylene-vinyl acetate copolymer resin can be used. Of course, two or more different types can be used in combination.

As the olefin resin forming the outer layer, the olefin resin of the above (A) or the olefin resin of the above (A) is used,
Unless the mixing ratio of the (meth) acrylate copolymer resin or the like deviates significantly from the above range, there is no particular difference in scratch resistance, high-frequency welder suitability, heat resistance, and cutting property. When the olefin resin (a) is used, a more flexible film or sheet is obtained than when the olefin resin (a) is used. Therefore, whether to use the olefin resin (a) or the olefin resin (a) as the olefin resin for forming the outer layer is determined, for example, in applications where higher flexibility is required. If it is used, it is appropriately performed depending on the use of the obtained film or sheet, such as using the olefin-based resin (a).

The olefin-based resin forming the outer layer may include, if necessary, a light stabilizer such as an antistatic agent, an antioxidant, a hindered amine-based compound, a lubricant, an ultraviolet ray, similarly to the olefin-based 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.

Further, as long as the properties of the obtained film / sheet are not impaired, polymers other than the above-mentioned olefin resins, specifically, low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, Polyethylene such as high-density polyethylene; isotactic polypropylene (including random and block copolymers of propylene and ethylene, ie, random polypropylene, block polypropylene, etc.); polybutene; olefin rubber; ethylene elastomer; hydrogenated styrene-butadiene Rubber; hydrogenated styrene-isoprene rubber; etc. may be mixed.

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 olefin-based resin multilayer film / sheet of the present invention also has the advantage that the interlayer adhesion is excellent without interposing an adhesive between the intermediate layer and the outer layer.

The olefin resin multilayer film of the present invention
The thickness of the sheet is not particularly limited, but is generally 0.03 to 2.0 mm as the above application.
It is.

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, since the portion where the coating film is formed significantly deteriorates the suitability for a high-frequency welder, a coating film may be formed. 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 8 and Comparative Examples 1 to 3 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 for an outer layer was used in a three-layer T-die extruder. Extruded, 0.3mm in total thickness, 0.2 in middle layer thickness
An olefin resin multilayer film having a thickness of 5 mm and a thickness of each outer layer of 0.025 mm was obtained. However, Comparative Example 2,
No. 3 is a single-layer film having a thickness of 0.3 mm without forming an outer layer. In addition, about the obtained film,
Suitable for high frequency welder, scratch resistance, transparency, interlayer adhesion,
Heat resistance and cutability were evaluated according to the following criteria.

A) Suitability for high-frequency welder ：: Joining possible without heating the welder blade ○: Joining possible by heating the welder blade to 40-60 ° C. △: Joining by heating the welder blade to 70 ° C. or higher Possible ×: High-frequency welding is practically impossible. B) Flaw resistance Gakushin-type friction tester (Kanakin No.3, No. 50 rubbing)
), The haze value (unit%) was measured based on JIS-K-6714, and compared with the haze value before rubbing. ：: haze increase is less than 20% x: haze increase is 20% or more c) transparency ：: haze value is less than 5% ：: haze value is 5% or more and less than 10% x: haze value is 10% or more d) Adhesion between layers ：: good (no separation between layers of each layer during welding of high-frequency welder) ×: poor (separation occurs between layers of each layer during welding of high-frequency welder) e) Heat resistance 、 １: 1 hour at 100 ° C No deformation is observed even when left undisturbed. X: Deformation is observed when left at 100 ° C. for 1 hour. F) Cutability ○: No deformation is observed when 50 films are stacked and cut. X: Film Deformation is seen in the film when cutting 50 sheets

[0031]

[Table 1]

For reference, FIG. 1 shows an enlarged sectional view of a part of the olefin resin multilayer film of Example 1. Reference numeral 1 in the figure denotes a multilayer film made of an olefin-based resin, and reference numeral 1 denotes
1 indicates an intermediate layer, and reference numerals 12 (a) and 12 (b) indicate outer layers, respectively.

[0033]

As described in detail above, the multilayer film / sheet made of an olefin resin of the present invention is excellent in high frequency welder suitability, scratch resistance, heat resistance, and cutting property, for stationery, various cases, packaging, and agriculture. It can be suitably used for applications 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.

Furthermore, the multilayer film / sheet made of an olefin resin of the present invention has excellent interlayer adhesion even without 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 showing a multilayer film made of an olefin-based resin of Example 1.

[Explanation of symbols]

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

Claims (4)

[Claims] An olefin resin multilayer film or sheet comprising an intermediate layer made of an olefin resin and outer layers made of an olefin resin formed on both surfaces thereof, wherein the olefin resin forming the intermediate layer is provided. 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 syndiotactic polypropylene. A multilayer film or sheet made of an olefin resin, which is a main olefin resin. 2. An olefin-based resin multilayer film or sheet comprising an olefin-based resin intermediate layer and an olefin-based resin outer layer 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 syndiotactic polypropylene and An olefin-based resin multilayer film or sheet, which is an olefin-based resin mainly comprising a mixture of at least one selected from ethylene- (meth) acrylate copolymer resins and ethylene-vinyl acetate copolymer resins. 3. The mixing ratio of one or more olefin resins selected from ethylene- (meth) acrylate copolymer resins and ethylene-vinyl acetate copolymer resins contained in the outer layer is 50% by weight or less. 3. The multilayer film or sheet made of the olefin resin according to 2. 4. The thickness ratio of the intermediate layer to the outer layer is 2: 1.
The olefin resin multilayer film or sheet according to any one of claims 1 to 3, wherein the ratio is in the range of from 20 to 20: 1.