JP2000177074A - Film or sheet made of olefinic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheet or film excellent in welder properties, damage resistance, transparency, interlaminar adhesiveness, heat resistance and heat insulating properties. SOLUTION: A sheet or film excellent in welder properties, damage resistance, transparency, interlaminar adhesiveness, heat resistance and heat insulating properties is obtained by forming a multilayered sheet or film made of an olefinic resin consisting of an intermediate layer 11 comprising an olefinic resin being a copolymer of ethylene and a monomer (A) having an ethylenic unsaturated bond and a carboxyl group or an anhydrous carboxylic acid group and copolymerizable with ethylene or a copolymer of ethylene, the monomer (A) and (meth)acrylic ester or a mixture of this copolymer and other ethylenic resin and outer layers 12a, 12b comprising an olefinic resin based on polypropylene.

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 details, 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 (meth) acrylate copolymer resin or an ethylene-vinyl acetate copolymer resin is known.

[0003]

The single-layer film or sheet comprising the above-mentioned ethylene-methyl (meth) acrylate copolymer resin or ethylene-vinyl acetate copolymer resin has flexibility and is suitable for high-frequency welding. In terms of having the advantage, 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 drawback that the surface is easily scratched (poor in scratch resistance) Conventionally, various proposals have been made to improve this, specifically, addition of a fatty acid amide and formation of a coating film on the surface have been made.

However, in order to improve the scratch resistance by the above-described method, a film / sheet made of an ethylene-methyl (meth) acrylate copolymer resin or an ethylene-vinyl acetate copolymer resin is originally possessed. In many cases, characteristics such as excellent suitability for high-frequency welding are impaired.

A single-layer film / sheet made of an ethylene-methyl (meth) acrylate copolymer resin or an ethylene-vinyl acetate copolymer resin is inferior in heat resistance to 80 to 9%.
Even at a temperature of about 0 ° C., there is a drawback that deformation is apt to occur, or the cutting property is poor, and the blade is hard to enter during cutting, so that the vicinity of the end (the end formed by cutting) is elongated and deformation is likely to occur. There was also a disadvantage.

On the other hand, in order to solve the above-mentioned problems, an outer layer made of polypropylene is formed on both sides of a film or sheet made of only an ethylene-methyl (meth) acrylate copolymer resin or an ethylene-vinyl acetate copolymer resin. Although also examined, generally used polypropylene, specifically, homopolypropylene which is a homopolymer of propylene, random polypropylene which is a random copolymer of propylene and ethylene, a block copolymer of propylene and ethylene When using polypropylene such as block polypropylene, ethylene-
It was practically impossible to directly laminate a film or sheet made of a methyl (meth) acrylate copolymer resin or an ethylene-vinyl acetate copolymer resin without using an adhesive or the like.

[0007] Further, an outer layer made of the above-mentioned polypropylene, which is generally used, is applied to the surface of a film or sheet made of an ethylene-methyl (meth) acrylate copolymer resin or an ethylene-vinyl acetate copolymer resin, by using a generally used adhesive. However, even if the film is laminated via the above, the obtained high-frequency welder suitability of the obtained film / sheet is lower than that of a single-layer film / sheet composed only of an ethylene-methyl (meth) acrylate copolymer resin or an ethylene-vinyl acetate copolymer resin. There was also a problem.

The present invention solves the above-mentioned problems, and it is said that a film / sheet comprising only an ethylene-methyl (meth) acrylate copolymer resin or an ethylene-vinyl acetate copolymer resin has excellent suitability for a high-frequency welder originally possessed. An object of the present invention is to provide a film / sheet having improved scratch resistance, heat resistance and cutability on the surface without impairing the properties.

[0009]

In order to solve the above-mentioned problems, the film / sheet of the present invention is characterized in that the ethylene resin forming the intermediate layer comprises ethylene and an ethylenically unsaturated bond and a carboxyl group or a carboxylic anhydride. A copolymer of a monomer (A) having a group and copolymerizable with ethylene or a copolymer of ethylene and a copolymer of (A) and (meth) acrylate, alone or in a mixture with another ethylene-based resin. An olefin resin-based multilayer film / sheet, wherein the olefin resin forming an outer layer is an olefin resin mainly composed of polypropylene.

As described above, the ethylene resin forming the intermediate layer of the olefin resin multilayer film / sheet of the present invention has ethylene and an ethylenically unsaturated bond and a carboxyl group or a carboxylic anhydride group, and It is an olefin resin which is a copolymer with a copolymerizable monomer (A) or a copolymer of ethylene and (A) and (meth) acrylate alone or as a mixture with another ethylene resin.

The monomer (A) having an ethylenically unsaturated bond and a carboxyl group or a carboxylic anhydride group and copolymerizable with ethylene includes, specifically, acrylic acid, methacrylic acid, fumaric acid, maleic acid and the like. Carboxylic anhydrides composed of these are mentioned. Further, the monomer (A) having an ethylenically unsaturated bond and a carboxyl group or a carboxylic anhydride group used in the present invention and copolymerizable with ethylene may be used alone or in combination of two or more. .

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

As the ethylene- (meth) acrylate copolymer resin, a resin having a (meth) acrylate component in an amount of 5 to 30% by weight is preferable. % By weight is more preferred.

Of course, the ethylene- (meth) acrylate copolymer resin may be a mixture of different types and contents of (meth) acrylate 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, those having a vinyl acetate component of 5 to 30% by weight are preferred, and those having a vinyl acetate component of 15 to 30% by weight are more preferred from the viewpoint of suitability for high frequency welding.

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.

As described above, the ethylene resin forming the intermediate layer has ethylene and an ethylenically unsaturated bond and a carboxyl group or a carboxylic anhydride group, and is copolymerized with a monomer (A) copolymerizable with ethylene. Olefinic resin which is a copolymer or a copolymer of ethylene and (A) and (meth) acrylate alone or as a mixture with other ethylene-based resins may be used, if necessary, with an antistatic agent and an antioxidant. And various additives such as a light stabilizer such as a hindered amine compound, a lubricant, an ultraviolet absorber, an inorganic filler, and a coloring agent such as a pigment.

The intermediate layer of the multilayer film / sheet made of an olefin resin of the present invention may be any of the above-mentioned ethylene and ethylenically unsaturated bonds and a carboxyl group or a carboxylic anhydride as long as the properties of the resulting film / sheet are not impaired. A copolymer with a monomer (A) having a group and copolymerizable with ethylene or a copolymer with ethylene and (A) and (meth) acrylate, and other copolymers, specifically Is a mixture of polyethylene such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene; polypropylene (homopolypropylene, random polypropylene, block polypropylene, etc.); polybutene; ethylene-based elastomer; olefin-based rubber; No problem.

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

The low melting point random polypropylene is, for example, a random polypropylene having a melting point of 140 ° C. or less, such as a random copolymer of propylene, ethylene and butene (propylene-ethylene-butene terpolymer).
The melting point referred to here is a differential scanning calorimeter (Diffe).
rental scanning calorime
ter) The temperature of the maximum peak of the second run (2ndrun) in the analysis.

Syndiotactic polypropylene is
For example, it is obtained by polymerizing using a metallocene catalyst.

In order to further improve the welding strength when the obtained olefin resin multilayer film / sheet is joined by a high frequency welder, a hydrogenated rubber is mixed with the above-mentioned olefin resin mainly composed of polypropylene. It is desirable to do. As this hydrogenated rubber,
Hydrogenated styrene-butadiene rubber, hydrogenated styrene-isoprene rubber, hydrogenated ethylene-butadiene block rubber, hydrogenated styrene-ethylene-butylene-styrene block copolymer rubber, and the like can be used. The mixing ratio when the above hydrogenated rubber is mixed with the olefin resin mainly composed of polypropylene for forming the outer layer is 9% for the olefin resin mainly composed of polypropylene.
8 to 70% by weight, hydrogenated rubber in a range of 2 to 30% by weight, particularly preferably 95 to 80% by weight of an olefin resin mainly composed of polypropylene, and 5 to 20% by weight of a hydrogenated rubber. It is.

The olefin resin mainly composed of polypropylene for forming the outer layer (including the above-mentioned mixture with the hydrogenated rubber, the same applies hereinafter) may be optionally used in the same manner as the ethylene resin for forming the intermediate layer. Various additives such as an antistatic agent, an antioxidant, a light stabilizer such as a hindered amine compound, a lubricant, an antiblocking agent, an ultraviolet absorber, 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, a polymer other than polypropylene, specifically low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, or high-density polyethylene may be used as the outer layer. Ethylene copolymers such as ethylene- (meth) acrylate copolymer and ethylene-vinyl acetate copolymer; polypropylene (homopolypropylene, random polypropylene, block polypropylene); polybutene; ethylene-based elastomer; And the like can be mixed.

The olefin resin multilayer film sheet of the present invention has outer layers formed on both surfaces of the intermediate layer. The multilayer film sheet of the present invention has excellent interlayer adhesion between the intermediate layer and the outer layer. Since there is no need to interpose an adhesive between the two layers, it is preferable to use a co-extrusion method or a co-extrusion inflation method in which the production process is simple. Of course, the intermediate layer and the outer layer are formed by a calender method, an extrusion method,
The multi-layer film of the present invention can also be formed separately by means such as inflation and then laminated by means such as heat lamination or bonding with an appropriate adhesive.
You can get a sheet.

The thickness of the multi-layer film / sheet made of olefin resin of the present invention is not particularly limited.
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 2: 1 to 40: 1 (that is, 1/2/1).
~ 1/40/1). If the ratio of the thickness of the intermediate layer and the outer layer deviates significantly from the above range,
It is not possible to obtain a multilayer film sheet that can solve the problems of the present invention. Note that the thickness of both outer layers does not necessarily need to be the same.

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

[0030]

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 Using a resin composition for an intermediate layer and a resin composition for an outer layer having the composition shown in Tables 1 and 2, co-extrusion was performed with a three-layer T-die extruder to obtain an olefin resin. A multilayer film was obtained. In addition, 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. The results are shown in Tables 1 and 2.

(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 higher Can be welded ×: High-frequency welder processing is practically impossible. (B) Scratch resistance Gakushin type friction tester (Kanakin No.3, rubbing frequency 50)
After the rubbing, the haze value (unit%) was measured based on JIS-K-6714 and compared with the haze value before rubbing. ：: increase in haze value is less than 20% ×: increase in haze value is 20% or more (c) transparency ○: haze value is less than 10% ×: haze value is 10% or more (d) interlayer adhesion ：: good (high frequency) ×: defective (easy to peel between layers of each layer during high frequency welding) (e) Heat resistance ○: even if left at 100 ° C. for 1 hour No deformation is observed. ×: Deformation is observed when left at 100 ° C. for 1 hour. (F) Cutability ：: When 50 films are stacked and cut, no deformation is observed at the end of the film. Deformation is seen at the film edge when 50 films are stacked and cut. * 1 Ethylene-Acrylic Nucleol N1207C (manufactured by DuPont Mitsui Polychemicals) * 2 Ethylene-vinyl acetate Evarate K2010 (manufactured by Sumitomo Chemical * 3 Ethylene-methyl (meth) acrylate Lexpearl RB3240 (manufactured by Nippon Polyolefin) * 4 Random polypropylene BT-200f (manufactured by Chisso) Melting point 148 ° C * 5 Low melting point random polypropylene Novatec PP FL40 (manufactured by Nippon Polychem) Melting point 13
5 ° C * 6 Syndiotactic polypropylene TEARO SPH0453E (manufactured by Mitsui Chemicals) * 7 Dynalon 1320P (manufactured by Nippon Synthetic Rubber) * 8 Delaminated during welder processing All numerical values for compositions in Tables 1 to 3 are parts by weight

[0033]

[Table 1]

[0034]

[Table 2]

[Comparative Examples 1 to 3] A multilayer film made of an olefin-based resin was prepared in the same manner as in the Example except that the ethylene-based fertilizing composition for the intermediate layer and the propylene-based resin composition for the outer layer were changed to those shown in Table 3. Obtained. However, in Comparative Example 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 cutting property in the same manner as in Examples 1 to 3. The results are shown in Table 3.

[0036]

[Table 3]

For reference, FIG. 1 shows a partially enlarged cross-sectional view of the olefin resin multilayer film of Example 5. In the drawing, reference numeral 1 denotes an olefin resin multilayer film, reference numeral 11 denotes an intermediate layer, and reference numerals 12 (a) and 12 (b) denote outer layers, respectively.

[0038]

As described in detail above, the olefin resin multilayer film / sheet of the present invention is excellent in high-frequency welder suitability, interlayer adhesion, scratch resistance, heat resistance and cutting properties, for stationery and various cases. Suitable for packaging, agricultural use, etc. Further, 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 olefin resin multilayer film / sheet of the present invention has excellent interlayer adhesion even without an adhesive between the intermediate layer and the outer layer. It can be manufactured.

Further, when the hydrogenated rubber is mixed with the olefin resin forming the outer layer, there is an advantage that the adhesive strength of the welded portion by the high frequency welding is further improved.

[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 the front page F term (reference) 4F100 AK04A AK04J AK07B AK07C AK24A AK24J AK25A AK25J AK62B AK62C AK66B AK66C AK68A AL01A AL04A BA03 BA06 BA10B BA10C BA16 GB01 GB20 BB07W BB12X BB14X

Claims (5)

[Claims] An olefin-based resin multilayer film or sheet comprising an ethylene-based resin intermediate layer and olefin-based resin outer layers formed on both surfaces thereof, wherein the ethylene-based resin forms the intermediate layer. Has a copolymer of a monomer (A) or a copolymer of ethylene and (A) and (meth) acrylate, which has an ethylene and an ethylenically unsaturated bond and a carboxyl group or a carboxylic anhydride group, and is copolymerizable with ethylene. Is an olefin-based resin that is a copolymer alone or a mixture with another ethylene-based resin, and the olefin-based resin forming the outer layer is an olefin-based resin mainly composed of polypropylene. Sheet. 2. An ethylene-based resin other than a copolymer having a carboxyl group or a carboxylic anhydride group in the intermediate layer is an ethylene-vinyl acetate copolymer resin or an ethylene- (meth) acrylate copolymer resin. Item 4. An olefin resin multilayer film or sheet according to Item 1. 3. The multilayer film or sheet according to claim 1, wherein the polypropylene of the outer layer is a low melting point random polypropylene. 4. The olefin resin multilayer film or sheet according to claim 1, wherein the polypropylene of the outer layer is syndiotactic polypropylene. 5. 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 4, wherein the ratio is in the range of from 40 to 1: 1.