JPS6147244A - Laminate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention has excellent transparency, hygiene, gas barrier properties, and chemical resistance, and is particularly suitable for molding containers for food, drink, medicine, etc. The present invention relates to a laminate useful as a packaging film or sheet.

(Prior Art) For example, laminates of nylon or polyester films and polyolefin films are well known and used in the field of food packaging.

In order to obtain these laminates, there are three methods: ■ Co-extrusion of nylon and polyolefin; ■ Extrusion coating lamination or thermocompression bonding of a polyolefin containing carboxyl group-containing polyolefin onto a nylon or polyester film; ■ A nylon or polyester film. There is a method of laminating a polyolefin film and a polyolefin film using an adhesive.

However, the interlayer adhesion strength and gas barrier properties are insufficient in the case of (1), and the glabella strength is sufficient in the case of (2), but the carboxyl group-containing polyolefin is expensive and may deteriorate in adhesive strength against some chemicals. In addition, since the method (2) uses an adhesive, it requires time-consuming work such as applying the adhesive and laminating, and like the method (2), it may deteriorate when exposed to some chemicals.

(Problems to be Solved by the Invention) The present invention has two advantages: 2. A lamination film or sheet and a polyolefin are bonded to each other with excellent chemical resistance and adhesive strength sufficient for practical use in a simple process without using ordinary adhesives. It provides the body.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, as a result of research, we have found that plastic films or A laminate is provided in which a sheet and a polyolefin film or sheet subjected to electrical discharge treatment are joined together by placing the treated surfaces on top of each other and applying heat and pressure.

In the present invention, the plastic film or sheet is made of acrylic resin such as polyester, nylon, polyhinyl chloride, polyolefin, ethylene/vinyl acetate copolymer, saponified product, polystyrene, polyacrylonitrile, polymethyl methacrylate, etc. It is a thing.

The material, thickness, or stretched or unstretched material may be selected depending on the purpose. When used for food packaging, these films or sheets are made of polyester, especially polyethylene terephthalate CP.
ET)j Made of nylon or polypropylene, preferably stretched.

In the present invention, a thin layer of various metals or their oxides is formed on the film or sheet by a dry brating method such as a vacuum evaporation method or a spackling method, which are known per se. Metals include aluminum, silicon, titanium, and tin.

Iron, gold, silver, copper, chromium, nifkel, magnesium, etc., and their oxides.

Alternatively, it may be glass, and it is also possible to perform mixed vapor deposition or multilayer vapor deposition depending on the purpose. The thickness of the thin layer can be determined depending on the purpose, ranging from a few molecules to several thousand molecules, but if it is necessary to maintain transparency, aluminum,
100% for metal-colored materials such as titanium, nickel, tin, iron, gold, silver, copper, chromium, magnesium, etc.
For metal oxides, silicon, or glass, the number is preferably several tens to several thousand. Among these, a thin silicon layer is particularly preferred for food applications because it maintains transparency, has good barrier properties, and has excellent ultraviolet blocking properties and flexibility, although it becomes yellow to brown as the film thickness increases. Further, when chemical resistance is required, gold and glass are particularly excellent, but depending on the purpose, titanium, silicon, or their oxides may also be sufficient for the purpose.

In the present invention, discharge treatment includes low temperature plasma treatment and corona discharge treatment.

The conditions for low temperature plasma treatment are lXl0-3~l
Discharge output 100W in Torr of oxygen, argon, nitrogen or helium gas, or a mixed gas containing these
Under the above conditions, the processing time is 1 second or more, preferably several seconds or more. Reduce discharge output.

Alternatively, if the treatment time is shortened, the adhesive strength decreases.

Note that low-temperature plasma is plasma caused by gas glow discharge under a gas pressure lower than atmospheric pressure, and is completely different from the plasma caused by energy rays emitted from high-temperature plasma, which is known from Japanese Patent Application Laid-Open No. 14759/1983. be.

9 Normal conditions are sufficient for the corona discharge treatment, and known treatment equipment such as the spark gap method, vacuum tube method, and solid state method can be used.The treatment atmosphere may also be air, argon gas, carbon dioxide gas, M elementary gas,
Single or mixed gases such as oxygen gas can be used. Also.

Processing power: 5 to 300 W/'rd
/llll1n, but in consideration of the balance between film deterioration due to corona discharge treatment and adhesion, it is preferably in the range of 10 to 50 W/rd/min. Of course, a commercially available corona discharge treated plastic film or sheet can also be used, but sufficient care must be taken to ensure the storage conditions after treatment and deterioration over time.

As the polyolefin film in the present invention, commercially available films such as polyethylene, polypropylene, ethylene-propylene copolymer, polybutene, etc. are sufficient,
It can be selected and used as appropriate depending on the purpose.

In the present invention, the heating and pressurizing conditions are from the softening temperature of the polyolefin to the melting temperature of the plastic film or sheet base material on which the transparent thin layer is formed,
For low density polyethylene, the temperature is about 100°C or more, for high density polyethylene it is about 135”C or more, and for polypropylene it is about 1
It is 50'C or higher. 200-2 for nylon film
Below 30'C.

For polyethylene terephthalate film, the temperature is 250°C or less. From an industrial standpoint, the pressure is applied using a heating roller and a backup roller, and the linear pressure is 0.5 Kg/a+1 or more, preferably in the range of 2 to 10 Kg/am.

At this time, if the plastic film or sheet with a transparent thin layer is in contact with the heating roller side and the polyolefin film is in contact with the bank-up roller side, it is possible to prevent the easily softened polyolefin film from adhering to the roller surface. It is advantageous. The surface of the backup roller is preferably treated with silicone resin or fluororesin so that it is heat resistant and difficult to adhere to.

After lamination, a cooling roller is usually used to cool the base material of the plastic film or sheet on which the transparent thin layer is formed, and then the material is wound onto a take-up roller.

The present invention will be explained in more detail below using Examples and Comparative Examples.

Comparative example 1 Table 1 shows the adhesive strength of the laminate obtained by the conventional method.

Table 1 Symbols in Table 1 are Ny, 6-nylon, PIET,
Polyethylene terephthalate, PE; polyethylene.

PPi polypropylene.

The specific bonding method of the conventional laminate in Table 1 is: ・Ny/PEO coextrusion 6-nylon resin (East side light, 0M1021-XF,
(melting point: approx. 225°C) was heated to 240°C, polyethylene resin (Mitsui Petrochemical Industries Sidelight, Heizenx 3300F, melting point: approx. 131'C) was heated and melted to 145°C, and coextruded using a T-die method using a method known per se. did.

・Instead of My/ppO coextruded polyethylene resin, polypropylene resin
@! l! The procedure was the same as the Ny/PEO coextrusion except that F2O3 (melting point approximately 160'C) was used and the heating and melting was 180°C.

- PET/PE (extrusion lamination) PET film (manufactured by Toshien, product name Lumirror P-11゜12μ) and polyethylene resin (manufactured by Mitsui Nisseki Polymer□Zero, Mirason I)
IP, softened 86°C) was extrusion laminated at 300''C.

・Ny/PE (Adhesive used) 6-Nylon film (manufactured by Unitika@, product name emblem, 15μ) and PR film (70μ) were bonded together using an 82-component urethane adhesive (manufactured by Toyo Morton, AD-98OA).
, AD-980B) at 100°C, and then subjected to aging at 40°C for 48 hours.

・P'ET/PP (using adhesive) 6-Instead of nylon film, use PET film (
A laminate was obtained in the same manner as Ny/PE except that Lumirror P41.12μ (trade name, manufactured by Toshi@) was used.

Example 1 A thin aluminum layer having a thickness of 100 mm was formed on a nylon film (emblem 15 μm) by vacuum deposition.

On the other hand, polyethylene film (manufactured by Tamapoly@, product name NB
-4 Single-side corona discharge treated 70μ) untreated side was subjected to corona discharge treatment in the atmosphere at a treatment voltage of 30 W/m/min. Then, the adhesive strength of the laminated film obtained by stacking the respective treated surfaces and joining them by heating and pressing at 190°C and a linear pressure of 3 kg/am was 400/15 m or more as measured by the cross peel method within 15 mm. there were.

Comparative Example 2 The adhesive strength of a contact film obtained in the same manner as in Example 1 using the same untreated polyethylene film instead of the corona discharge treated polyethylene film was 50 g/15
It was less than mm.

Example 2 On the same biaxially stretched polyethylene terephthalate film (thickness: 12 μm) as in Comparative Example 1, a thin aluminum layer having a thickness of 90 μm was formed by vacuum evaporation. l on this thin layer surface
400W, 20 in oxygen gas at Xl0″″” Torr
A polyethylene film (manufactured by Tamapoly ■, trade name NB-1, 70μ) that has been subjected to low temperature plasma treatment under the conditions of 180℃ and a linear pressure of 5Kg/co+
Heat sealed and laminated. The adhesive strength of the obtained laminate was 600 g/15 m or more (film breakage).

Examples 3-1 Biaxially oriented polyethylene terephthalate film (thickness 2
A thin layer of the material shown in Table 2 was prepared on a 5 μm layer using the respective metal as the sputtering material.

Reactive sputtering was performed under the conditions of argon/oxygen mixed gas and 1xio Torr to form thin layers of respective thicknesses. Therefore, it appears that what is shown as silicon oxide in Table 2 is actually a mixture of both silicon monoxide and silicon dioxide, or a mixture of a portion of silicon. The same applies to other oxides in Table 2. However, the glass of Example 10 was sputtered in argon gas.

A polyethylene film subjected to the same corona discharge treatment as in Example 1 was bonded to this thin layer surface under heat and pressure to create a laminate, and the results of measuring the adhesive strength, oxygen gas permeability, and moisture permeability are shown in Table 2. Shown below.

9 In this specification, oxygen gas permeability is measured using the isobaric method (
The unit is ml/rd, 24hr, 25℃), and the moisture permeability is JIS Z 020B (D force 7b method (40℃, 90% R
H (unit: g/rrr), and indicates that ND is not detected.

Example 11 A glass layer having a thickness of 50 ml was formed on the same biaxially stretched polyethylene terrestrial film as in Comparative Example 1 by the Svafkling method. IX 10-3 Torr on this thin layer surface
Polyethylene (manufactured by Kuma Poly ■, trade name: UB-1, 60μ) that has been subjected to low-temperature plasma treatment under argon gas conditions of 600W for 30 seconds is placed on top of the treated surfaces for 18 seconds.
Heat-seal lamination was performed at 0° C. and a linear pressure of 5 kg/an, and the adhesive strength of the resulting laminate was 500 g/151 m. In addition, a flat bag was made using the obtained laminate by a conventional method, and after filling with 75% sulfuric acid aqueous solution, it was sealed and kept at 25°C.
It was left at room temperature for 20 days. Adhesive strength after storage: 400g
/15m, there was almost no deterioration.

Comparative Example 3 Instead of the polyethylene of Example 11, an ionomer resin (manufactured by Mitsui Polychemical ■, livestock product name Himiran 1652) was used.
40μ was extrusion coated and laminated, and the adhesive strength of the similarly obtained laminate was 450g/15m. Similarly, the adhesive strength after storage filled with a 75% sulfuric acid aqueous solution was 50 g/1511 or less, which significantly deteriorated.

Example 12 A thin titanium layer having a thickness of 20 mm was formed on the same nylon film as in Example 1 by vacuum evaporation. On the other hand, the untreated side of a polyethylene film (manufactured by Tamabori ■, trade name, DT-2, one side corona discharge treated 70μ) was subjected to low-temperature plasma treatment under the conditions shown in Table 3, and the treated sides were overlapped with a nylon film. Total 180℃, linear pressure 3Kg/c
Heat seal lamination was performed at n.

The adhesive strength of the obtained laminate was as shown in Table 3.

Varnish 1,000 Songs Table 3 *Example 13 of mixed gas with approximately the same amount Film molded from high pressure polyethylene resin (manufactured by Mitsui Polychemicals, trade name Mirason NEO45) <40
μ) at 30 W/rd/min in air.

Corona discharge treatment was performed with a processing power of . And Example 1
A CPP film (manufactured by Toshi@, product name: Torefan 393L 70) with 90 thin layers of aluminum formed in the same way as
The treated surface of μ) and the treated surface of the polyethylene film were overlapped and heated to 150°C using a Teflon-coated heating roll.
, and were joined by heating and pressing at a linear pressure of I kg/cm. The adhesive strength of the obtained laminated film was 500/15m.

Claims (1)

[Claims] 1. A transparent thin layer of one or more types selected from metals, their oxides, or glasses is formed on the surface of a plastic film or sheet by a dry-brating method, and the treated surface is subjected to discharge treatment. A laminate made by heat-sealing polyolefin in-film or sheets. 2. The discharge treatment is characterized by low-temperature plasma treatment in oxygen, argon, nitrogen, or helium gas, or a mixed gas containing these at 1×10^-^3 to 1 Torr, under conditions of a discharge output of 100 W or more. A laminate according to claim 1.