JP3817085B2 - Transparent high barrier laminate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is excellent in transparency, gas barrier properties, and antistatic properties. Packaging for articles that require air resistance, moisture resistance, etc. such as foods, pharmaceuticals, seasonings, spices, fragrances, and detergents. The present invention relates to a transparent high-barrier laminate suitable for use as a material.
[0002]
[Prior art]
Conventional barrier film packaging materials (barrier laminates) include: (1) a physical vapor deposition method (PVD method) or a chemical vapor deposition method (CVD method) on at least one side of a polymer film; There are known one provided with a vapor deposition film, (2) one formed by vapor deposition of a metal such as aluminum, and (3) one coated with a polymer having a relatively high resistance to air and moisture.
[0003]
Such conventional barrier laminates have the following problems.
(1) Transparent barrier laminates deposited with silicon oxide or aluminum oxide have been widely used in recent years for their excellent transparency, air resistance, and moisture resistance. Cracks and cracks occur in the deposited film due to stress, resulting in problems such as reduced barrier properties, and the deposited film is gray or brownish. There were problems such as being hard to withstand.
[0004]
(2) A polymer film formed by vapor deposition of metal such as aluminum on at least one side is excellent in suppressing the passage of ultraviolet rays, air resistance, moisture resistance, etc., and has been widely used in the past. Cannot be seen, and there is a problem that it does not have microwave oven suitability.
[0005]
In addition, (3) a polymer film coated with at least one other polymer that is relatively excellent in air resistance, moisture resistance, etc. can be manufactured at a relatively low cost and has a great deal of flexibility and selection. Things are used. However, most of these have insufficient air permeability and moisture resistance, and have problems inferior to the former two in such functions.
[0006]
[Problems to be solved by the invention]
The present invention has high air permeability resistance (small oxygen permeability) and moisture permeability resistance (low moisture permeability), which are not possessed by conventional barrier laminates, and also has good interlayer adhesion. It is an object to provide a transparent high barrier laminate having excellent printability and bendability, and excellent antistatic properties.
[0007]
[Means for Solving the Problems]
The present invention provides at least a transparent inorganic oxide thin film (B) and an ethylene-vinyl alcohol copolymer (EVOH) resin layer (C) having a thickness of 0.1 to 1 g / m ² on at least one surface of the polymer film (A). A transparent high-barrier laminate, wherein the ethylene-vinyl alcohol copolymer (EVOH) resin layer (C) contains an antistatic induction agent in the layer. It is a transparent high-barrier laminate, and further has an oxygen permeability (OK) of 30 cc or less after gelbotest (ASTM-E-392-74) of 1.5 cc / m ² · 24 hs or less, and a water vapor transmission rate (WK). The transparent high-barrier laminate described above having a weight of 2.0 g / m ² · 24 hs or less.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the transparent high barrier laminate of the present invention, the polymer film (A) is not particularly limited as long as it has excellent heat resistance, machinability, and chemical stability, and a conventional barrier laminate. Any of those used in can be used. For example, polyarylate, polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, polypropylene, polycarbonate, polystyrene, polyamide (nylon), polyamideimide, polyethylene, polyvinyl chloride, acrylic resin, polynorbornene Films made from a single polymer such as a resin, synthetic resin films such as copolymer films of these polymers, and films such as artificial resin films such as cellulose acetate, and two or more of these films are laminated. The composite film which is the multilayer film formed is mentioned. Further, a film obtained by blending two or more of these polymers may be used. For example, a polyethylene terephthalate-isophthalate copolymer may be blended with polyethylene terephthalate.
[0009]
Further, these films are preliminarily plasma-laminated before laminating the transparent inorganic oxide thin film (B) and the ethylene-vinyl alcohol copolymer (EVOH) resin layer (C) having a thickness of 0.1 to 1 g / m ^2. Physical treatment such as treatment, pretreatment with a silane coupling agent, etc., and formation of an undercoat layer may be performed.
In addition to the film, the polymer film (A) in the present invention is required to be laminated in two layers (B) and (C), and various other than the two layers as long as the effects of the present invention are not impaired. Known undercoat layers, primer layers, protective layers, colored layers, printed layers, seal layers, and the like, and further include modifiers such as ultraviolet absorbers, electrostatic induction antistatic agents, etc. It may be kneaded into a film-forming polymer, or may be contained in an undercoat layer or a protective layer.
The thickness of these films is not particularly limited, but is preferably about 4 to 200 μm.
[0010]
The formation of the transparent inorganic oxide thin film (B) in the present invention is for obtaining air resistance and moisture resistance, and the oxygen permeability of the transparent high barrier laminate of the present invention is 5 cc / m ² · 24 hs or less. preferably 3cc / m ² · 24hs or less, more preferably not more than 1.5cc / m ² · 24hs, moisture permeability 5g / m ² · 24hs or less, preferably 3g / m ² · 24hs or less, more preferably 2.0 g / m ² · 24 hs or less.
[0011]
The transparent inorganic oxide thin film (B) in the present invention is not particularly limited as long as it has high air permeability and moisture resistance, and is excellent in transparency. From the viewpoints of environmental conservation and safety, preferably, one or a mixture of two or more selected from oxides of silicon or oxides of aluminum can be used.
Most preferable as these transparent inorganic oxide thin films (B) are: (1) a weight ratio of silicon oxide to aluminum oxide of 9/1 to 5/5, and (2) silicon oxide. It is a kind selected from Si _X O _Y having X = 1 and Y = 1.1 to 1.9, more preferably X = 1 and Y = 1.2 to 1.8. By selecting, the barrier property, transparent colorlessness, adhesion between layers, and bending resistance of the transparent high-barrier laminate are more preferable.
The formation of the transparent inorganic oxide thin film (B) on the polymer film (A) can be performed by a conventionally known physical vapor deposition method (PVD method) such as a vacuum vapor deposition method, a sputtering method, an ion plating method, a plasma vapor deposition method, Or reactive vacuum deposition or reaction in an atmosphere of oxygen gas or a mixture of these gases and an inert gas such as argon or nitrogen. It is formed directly on one side of the polymer film by a conventionally known chemical vapor deposition method (CVD method) such as reactive sputtering method, reactive ion plating method or reactive plasma vapor deposition method, or it is formed via an undercoat layer.
[0012]
The thickness of the transparent inorganic oxide thin film (B) is appropriately selected from the range of usually 10 nm to 300 nm, preferably 30 nm to 100 nm. When the thickness of the transparent inorganic oxide thin film (B) is less than 10 nm, the barrier property is insufficient, which is not preferable. On the other hand, when the thickness is more than 300 nm, it is not preferable because cracks are easily generated. This is not a good idea and is not preferable.
[0013]
The ethylene-vinyl alcohol copolymer (EVOH) resin layer (C) having a thickness of 0.1 to 1 g / m ² in the transparent high barrier laminate of the present invention is a known ethylene-vinyl alcohol copolymer as a gas barrier resin. (EVOH) resin can be used, and its formation is performed by applying a liquid containing the resin by a normal coating method such as a roll coating method, a gravure coating method, a reverse coating method, etc., and drying, if necessary. To be implemented.
[0014]
In the present invention, by laminating an ethylene-vinyl alcohol copolymer (EVOH) resin layer (C) having a thickness of 0.1 to 1 g / m ² with a transparent inorganic oxide thin film (B), (C) and (B ) With excellent adhesion, air permeation resistance (low oxygen permeability), moisture permeation resistance (low water permeation), printability, and flexibility for bending Moreover, a transparent high barrier laminate having excellent antistatic properties can be obtained.
The thickness of the ethylene-vinyl alcohol copolymer (EVOH) resin layer (C) is preferably from 0.1 to 1 g / m ² , more preferably from 0.1 to 0.5 g / m ² . When less than 1 g / m ² , the effect of laminating the resin together with the transparent inorganic oxide thin film (B) is not obtained. Conversely, when it exceeds 1 g / m ² , the transparent inorganic oxide is not only economical but also economical. Adhesiveness with the physical thin film (B) is lowered, and there are problems such as peeling off from the transparent inorganic oxide thin film (B) during practical use as a packaging material, for example, when laminated with a sealing layer or at the time of sealing. It will be a thing.
As a preferable form in the present invention, a form in which an electrostatic induction preventing agent is added and contained in the ethylene-vinyl alcohol copolymer (EVOH) resin layer (C) can be mentioned. The antistatic induction agent in the present invention is an antistatic agent such as acrylic resin (eg, Konishi; Bondip PA100), and a transparent high barrier laminate is often laminated with a seal layer or other layers. Even in that case, the addition of the static induction inhibitor to the resin layer (C) can maintain sufficient antistatic properties in the outermost layer of the laminate, and the static induction inhibitor in the resin layer (C). Is added in an amount of 5 to 50% by weight.
[0015]
【Example】
The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.
[0016]
* Example 1
A polyethylene terephthalate film having a thickness of 12 μm was used as the polymer film (A), and Si _X O _Y (X = 1.0, Y = 1.5) was formed on the film surface by vapor deposition to a thickness of 100 nm. (EVOH) Resin layer (Nippon; Soar 30L) (C) is diluted with water / isopropanol (weight ratio 3: 1) and then formed by gravure coating to a dry film thickness of 0.35 g / m ² Thus, a transparent high barrier laminate was obtained.
The obtained transparent high barrier laminate had an initial oxygen permeability (OS, the same applies hereinafter) of 0.6 cc / m ² · 24 hs, and an initial moisture permeability (WS, the same applies hereinafter) of 0.5 g / m ² · 24 hs. Met.
Further, after printing on the layer (C) using urethane-based ink, the oxygen transmission rate (OP, the same applies hereinafter) is 0.6 cc / m ² · 24 hs, and the moisture permeability (WP, the same applies hereinafter) is 0. It was 6 g / m ² · 24 hs.
Furthermore, the oxygen permeability (OK, the same applies hereinafter) after 30 bending processes according to ASTM-E-392-74 using a gelbo test machine is 0.6 cc / m ² · 24 hs, and the water vapor transmission rate (WK, lower) The same) was 0.6 g / m ² · 24 hs.
The obtained transparent high-barrier laminate was laminated with a CPP film of 24 μm, sealed with silica powder, and tested for sealing properties. The results (RS, the same applies hereinafter) had almost no problems, and gas barrier properties due to poor sealing. There was no decline.
[0017]
* Example 2
Transparent in the same manner as in Example 1 except that 20% of the electrostatic induction inhibitor (Konishi; Bondeep PA100) was added to the (EVOH) resin layer (Nippon; Soar 30L) (C) in terms of solid weight. A high barrier laminate was obtained.
Evaluation of the transparent high-barrier laminate obtained in the same manner as in Example 1 was conducted. The results were that OS was 0.7 cc / m ² · 24 hs and WS was 0.5 g / m ² · 24 hs. , OP is 0.7 cc / m ² · 24 hs, WP is 0.5 g / m ² · 24 hs, OK is 0.8 cc / m ² · 24 hs, and WK is 0.5 g / m ²・ It was 24hs. Furthermore, there was almost no problem with RS, and no deterioration in gas barrier properties due to poor sealing was observed.
[0018]
* Comparative Example 1
A transparent barrier laminate was obtained in the same manner as in Example 1, except that the (EVOH) resin layer (Nichigo; Soar 30L) (C) was not formed.
Evaluation of the transparent high-barrier laminate obtained in the same manner as in Example 1 was conducted. As a result, OS was 1.5 cc / m ² · 24 hs and WS was 2.0 g / m ² · 24 hs. , OP is 3.2 cc / m ² · 24 hs, WP is 3.5 g / m ² · 24 hs, OK is 10.2 cc / m ² · 24 hs, and WK is 5.0 g / m ²・ It was 24hs. In addition, the gas barrier properties of RS due to poor sealing were observed.
[0019]
【The invention's effect】
The transparent high-barrier laminate of the present invention has excellent oxygen permeability, moisture permeability, printability, antistatic properties, excellent bending resistance, and a microwave oven packaging material, In particular, it is extremely useful as a food packaging material.

Claims (1)

On at least one side of the polyethylene terephthalate (PET) film (A),
at least,
A transparent inorganic oxide thin film (B);
An ethylene-vinyl alcohol copolymer (EVOH) resin layer (C);
A laminate formed by laminating
The transparent inorganic oxide thin film (B) is a silicon oxide represented by SixOy (x = 1, y = 1.2 to 1.8), and has a thickness of 10 nm to 300 nm.
The EVOH resin layer (C) contains an acrylic resin-based antistatic induction agent in the layer so that the additive content in the EVOH resin layer (C) is 5 wt% to 50 wt%. And the thickness is 0.1 to 1.0 g / m ² ,
The oxygen transmission rate (OK) after performing the gelbo test (ASTM-E-392-74) 30 times on the laminate is 1.5 cc / m ² · 24 hs or less, and the moisture permeability (WK) is 2. 0 g / m ² · 24 hs or less,
A transparent high-barrier laminate characterized by the above.