JP2016020044A - Olefin-based resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an olefin-based resin film capable of suppressing breed out and excellent in scratch resistance and high frequency welder deposition property, irrespective of being molded by using renewable biomass.SOLUTION: An olefin-based resin film is constituted by upper and lower layers composed of an olefin-based resin and an intermediate layer composed of polyethylene synthesized from bioethanol. The upper and lower layers are preferably formed by containing an ionomer resin of 1 to 15 wt.%.SELECTED DRAWING: None

Description

  The present invention relates to a film comprising an olefin resin, and more particularly to an olefin resin film comprising polyethylene synthesized from bioethanol, and having excellent high-frequency welder weldability. About.

  When processing an original film into a name tag case or clear file, the original film is cut or die-cut into a specific shape, and the overlapping edges are bonded with an adhesive, or heat-sealed or welded by high-frequency welder processing ( Process).

  When pasting with an adhesive, there is a problem that the transparency of the bonded part is impaired or the bonded part becomes hard, and in heat sealing, it depends on the heat conduction of the object to be heated, so it heats up to the inside When it does, there is a problem that it takes a long time, and thereby, the heat influences even on the portion where the welding is not performed (the welding is not performed).

On the other hand, since the high-frequency welder is for internally heating only the welded portion of the object to be heated, it can be welded in a short time and without affecting the portion that is not welded (not welded). In addition, since it is heated uniformly from the inside of the object to be heated, it has excellent welding strength and can perform welding with stable quality in an application time of only a few seconds. Because it is a very clean processing method that does not occur, it can be said that it is an excellent processing method for name tag cases and clear files.
As an olefin resin film used for name tag cases and clear files, a resin having a polarity excellent in suitability for high-frequency welder is used as an intermediate layer, and a layer of resin (for example, polyethylene resin or polypropylene resin) having excellent scratch resistance on both sides of the layer. There has been proposed a three-layer olefin resin film which is manufactured by providing a material and has excellent high-frequency welder suitability and scratch resistance (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-277893

By the way, our daily life is made up of oil, a fossil resource. Needless to say, most of the gasoline used in automobiles, kerosene used in stoves, and plastics are made from petroleum. Although oil is used in many situations like this, it is said that oil is a modification of ancient animals and plants, and its amount is limited. Furthermore, a lot of carbon dioxide is generated by refining and using the oil.
In response to such problems, there is a demand for a shift from petroleum-derived materials to an industrial system using renewable biomass.
However, since synthetic resins that are polymerized using biomass raw materials as starting materials use various additives in the polymerization stage, the additives bleed out after the molding process, causing the problem that the surface of the molded product becomes sticky or whitens. there were.

  It is an object of the present invention to provide an olefin-based resin film that solves the above problems, that is, has no bleed-out problem even when renewable biomass is used, and has excellent scratch resistance and high-frequency welder weldability. .

  The present invention has been variously studied to solve the above problems. As a result, an olefin resin film composed of an upper and lower layer made of an olefin resin and an intermediate layer made of polyethylene synthesized from bioethanol has scratch resistance and The present invention has been completed by finding out that it has excellent high frequency welder weldability.

The present invention has been made under such knowledge, and the gist thereof is as follows.
(1) An olefin resin film comprising an upper layer and a lower layer made of an olefin resin, and an intermediate layer made of polyethylene synthesized from bioethanol.
(2) The olefin resin film as described in (1), wherein the upper and lower layers contain 1 to 15% by weight of an ionomer resin.

According to the present invention, an olefin resin film excellent in scratch resistance and high-frequency welder weldability can be provided.
Moreover, in this invention, the polyethylene synthesize | combined from bioethanol, and what is called biomass plastics are used as a constituent material of a film. Biomass plastic does not generate new carbon dioxide in the atmosphere even if it is incinerated. Therefore, the present invention can provide an olefin resin film with reduced environmental load.

  Hereinafter, the present invention will be described in detail. The present invention is an olefin resin film comprising an upper and lower layer made of an olefin resin and an intermediate layer made of polyethylene synthesized from bioethanol.

  The upper and lower layers of the olefin resin film of the present invention are made of an olefin resin. Examples of the olefin resin include low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid. Examples include ethylene resins such as methyl copolymers, and polypropylene resins such as random polypropylene, block polypropylene, and homopolypropylene. In the present invention, it is preferable to use random polypropylene polymerized with a metallocene catalyst. Use of random polypropylene polymerized with a metallocene catalyst is preferable because it has the effect of suppressing bleed-out of additives added in the polymerization stage of polyethylene synthesized from bioethanol in an intermediate layer described later.

  An ionomer resin may be added to the upper and lower layers. The ionomer resin is prepared by crosslinking a binary copolymer or a ternary copolymer containing ethylene and (meth) acrylic acid and / or (meth) acrylic acid acrylic ester as a constituent component of the polymer with a metal ion. However, in the present invention, those crosslinked with potassium ions are preferably used. Since the ionomer crosslinked with potassium ion has a higher dielectric constant than that obtained by crosslinking with other metal ions (for example, zinc ion, sodium ion, lithium ion, magnesium ion, etc.), High frequency welder performance.

  The effect of the ionomer resin content is 1% by weight or more, and its specific range is 1 to 15% by weight. When it exceeds 15% by weight, the transparency tends to be impaired.

The middle layer of the olefin resin film of the present invention is made of polyethylene synthesized from bioethanol. Bioethanol is derived from sugar cane and corn.
The reason for polyethylene synthesized from bioethanol is not clear, but it is the polymerization of other general-purpose polyethylene, such as ethylene obtained by petroleum refining and α-olefin of comonomer species in the presence of a metallocene catalyst. Compared with the obtained linear low density polyethylene (LLDPE) or the like, the high frequency welder suitability is excellent.
Examples of the polyethylene synthesized from the bioethanol include high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). The linear low-density polyethylene has a low melting point and particularly high-frequency welder properties. (LLDPE) is preferred.

The intermediate layer may also contain an ionomer resin, similar to the upper and lower layers.
As ionomer resin, the thing similar to what is used by the said upper and lower layers is mentioned, The content is the range of 1 to 15 weight%.

  Polyethylene synthesized from bioethanol is easy to bleed out after molding. However, in the present invention, since the polyolefin resin is formed on the upper and lower surfaces of polyethylene synthesized from bioethanol, the entire film is formed. Bleed-out can be suppressed.

  Various additives such as an antistatic agent, an antioxidant, a light stabilizer such as a hindered amine compound, a lubricant, an ultraviolet absorber, an inorganic filler, and a pigment may be added to the upper and lower layers and the middle layer as necessary. Good.

  The intermediate layer of the olefin-based resin film of the present invention is a low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate as long as the properties of the resulting olefin-based resin film are not impaired. An ethylene resin such as a copolymer, an ethylene- (meth) acrylic acid copolymer, or an ethylene-methyl (meth) acrylate copolymer may be mixed.

  The olefin-based resin film of the present invention is formed by forming upper and lower layers on both surfaces of an intermediate layer. Preferably, the forming means is a coextrusion method or a coextrusion inflation method with a simple manufacturing process. Of course, the intermediate layer and the upper and lower layers are separately formed by means of a calendar method, an extrusion method, an inflation method, etc., and they are laminated by means such as thermal lamination or adhesion with an appropriate adhesive. An olefin resin film can be obtained. In addition, the olefin resin film of the present invention also has an advantage of excellent interlayer adhesion without interposing an adhesive between the intermediate layer and the upper and lower layers.

  Although it does not specifically limit about the thickness of the olefin resin film of this invention, Generally, it is 0.03-2.0 mm as the said use.

In the olefin resin film of the present invention, the ratio of the thickness of the intermediate layer and the upper and lower layers is in the range of 1: 2: 1 to 1: 20: 1 in the upper layer: intermediate layer: lower layer, preferably 1: The range is 4: 1 to 1: 16: 1.
In addition, the thickness and resin composition of an upper layer and a lower layer do not necessarily need to be the same.

  Since the olefin resin film of the present invention is excellent in high frequency welder weldability, it is suitable for use in applications requiring secondary processing.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited by these Examples.

<Examples 1 to 10>
The resin composition having the formulation shown in Table 1 was subjected to T-die extrusion molding to produce a film having a layer ratio of upper layer: intermediate layer: lower layer = 1: 8: 1 and a thickness of 200 μm.

<Comparative Examples 1-3>
The resin composition having the formulation shown in Table 1 was T-die extruded to produce a single layer film having a thickness of 200 μm.

In the table;
・ Polyolefin 1
Random polypropylene polymerized with metallocene catalyst MFR = 7.0
・ Polyolefin 2
Random polypropylene polymerized with Ziegler-Natta catalyst MFR = 7.0
・ Polyolefin 3
Evaflex EV430RC (ethylene-vinyl acetate copolymer vinyl acetate content: 19% by weight) manufactured by Mitsui DuPont Polychemical Co., Ltd.
・ Biomass polyethylene 1
Braskem SLL218 (Linear low density polyethylene synthesized from bioethanol made from sugarcane)
・ Biomass polyethylene 2
Braschem SGF4950 (High-density polyethylene synthesized from bioethanol made from sugarcane)
・ Ionomer 1
An ionomer obtained by crosslinking an ethylene-methacrylic acid copolymer having an acid content of 12% by weight with potassium ions, MFR: 5.0 g / 10 min (230 ° C. × 2.16 kgf)
・ Ionomer 2
An ionomer in which an ethylene-methacrylic acid-acrylic acid ester copolymer having an acid content of 12% by weight is crosslinked with zinc ion, MFR: 1.0 g / min (230 ° C. × 2.16 kg f)
・ Ionomer 3
An ionomer obtained by crosslinking an ethylene-methacrylic acid copolymer having an acid content of 7% by weight with sodium ions, MFR: 0.9 g / min (230 ° C. × 2.16 kgf)
The unit of numerical values in Table 1 is “% by weight”.

  The following tests and evaluations were performed on the films obtained in each Example and Comparative Example.

<High frequency welder weldability>
Using a high-frequency welder apparatus with an output of 4 W, the synchronization rate and welding time when two films were stacked and welded were measured and evaluated according to the following criteria.
◎ Welding at 60% tuning rate and 2 seconds transmission time
○ Welding at a synchronization rate of 60 and a transmission time of 4 seconds
× Not welded

<Scratch resistance>
The surface condition of the film after visually rubbing 100 times with a load of 500 g was visually observed with a Gakushin type friction tester and evaluated according to the following criteria.
○ No scratches △ Slightly scratches × Scratches are conspicuous

<Transparency>
The haze value was measured with a haze meter and evaluated according to the following criteria.
○ Haze value is 10% or less × Haze value exceeds 10%

<Bleedability>
One week after molding, the film surface was wiped with a cloth and evaluated according to the following criteria.
○ No deposits are observed on the fabric surface
△ Some deposits are observed on the fabric surface
× Conspicuous deposits are observed on the fabric surface

The olefin-based resin films of Examples 1 to 10 have no bleeding out and are excellent in high-frequency welder weldability, scratch resistance, and transparency, and thus are suitable as a film for secondary processing. Moreover, since the film of Examples 1-10 contains biomass plastic, it is a film with reduced environmental load.

Claims (2)

An olefin resin film comprising an upper layer and a lower layer made of an olefin resin and an intermediate layer made of polyethylene synthesized from bioethanol. The olefin resin film according to claim 1, wherein the upper and lower layers contain 1 to 15% by weight of an ionomer resin.