JPS59106958A - Laminate containing aluminum layer - 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] More specifically, steam treatment such as retort heat sterilization treatment,
Alternatively, the present invention relates to a laminate containing metallic aluminum and an aluminum layer mainly made of plastic or paper material, which retains metallic luster even when subjected to hot water treatment such as hot water sterilization treatment.

Conventional packaging materials, especially those used for containers (such as bags, bottles, cans, etc.) that can withstand long-term storage of food at room temperature, and whose main layer is plastic or paper are gas barrier materials. An organic film (ethylene-based film) with excellent gas barrier properties was used to ensure the
Most of them were made of aluminum foil (manufactured by rolling, and usually has a thickness of 8 μm or more) or laminates such as vinyl alcohol copolymer, polyvinylidene chloride, cellophane, etc.). However, the gas barrier properties of the former organic film are not sufficient, and deterioration of the food contents due to oxidation is usually prevented by refrigerated storage or by increasing the thickness of the organic film.

On the other hand, when using the latter aluminum foil, during the retort heat sterilization treatment or hot water sterilization treatment after filling and sealing the food contents, high-temperature water vapor permeates through the plastic film on the aluminum foil and connects to the aluminum surface. In reaction, the surface tends to change unevenly, lose its metallic luster, and take on a mottled, grayish, dull appearance. Furthermore, aluminum foil is relatively expensive and has the problem of not being applicable to containers such as plastic bottles.

The present invention has been made in view of the problems of the prior art described above, and the present invention maintains metallic luster even when high-temperature water vapor permeates through treatments such as retort heat sterilization treatment and hot water sterilization treatment. It is an object of the present invention to provide a packaging laminate having a high-class image, excellent gas barrier properties, and low material cost, the main layers being metal aluminum and plastics or paper materials.

In order to achieve the above object, the present invention provides a base layer mainly made of plastics or paper with a thickness of about 300 mm to 300 mm.
A laminate in which a 0X vapor-deposited metal aluminum layer is formed, and a protective film layer is formed on the metal aluminum layer, wherein at least a portion of the base layer and/or the protective film layer is in contact with the aluminum layer, The present invention provides a laminate including an aluminum layer, characterized in that the resin contains free carboxyl groups in an amount of 0.1 to 1700 milliJ equivalent per 100 grams of resin.

The present invention will be described below with reference to the drawings which are examples.

The laminate 1 shown in FIG. 1 includes a base layer 2, a vapor-deposited metal aluminum layer 3 (hereinafter referred to as the aluminum layer), and a protective film layer 4. The aluminum layer 3 has a thickness of about 300-3
0001, metal aluminum is placed on the base layer 2,
It is formed by attachment using a so-called vapor phase plating method such as vacuum evaporation, ion blating, or sputtering.

The base layer 2 must have the mechanical strength (in the case of a film) and heat resistance to withstand this formation. Furthermore, if the container is to be subjected to retort heat sterilization treatment, hot water sterilization treatment, etc. after being formed into a container, filled with contents, and sealed, properties such as hot water resistance, thermal dimensional stability, and water swelling resistance that can withstand these treatments must be maintained. Must have. Plastics that meet these physical conditions and can be used for the base layer 2 include linear polyester resins such as oriented polyethylene terephthalate, low-density polyethylene, high-density polyethylene, and more!
+) f Robylene, polyolefin resins such as ethylene-propylene copolymers, acrylic resins, polystyrene resins,
ASIt resin, ABS resin, polyamide resin, polyimide resin, polyimine resin, vinyl chloride resin, vinyl chloride
Vinyl acetate copolymer, ethylene-vinyl acetate copolymer,
Vinylidene copolymer, urea resin, phenol resin, epoxy resin, melamine resin, urethane resin, xylene
Examples include formaldehyde resin, acetal resin, coumaron indene resin, noaryl phthalate resin, and fluorine resin.

Furthermore, due to the permeation of high-temperature water vapor, the aluminum layer 3
In order for the base layer 2 to not lose its metallic luster, the resin in at least the portion of the base layer 2 that is in contact with the aluminum layer 3 (for example, in the case of a laminate, the resin in the layer that is in contact with the aluminum layer 3) must convert free carboxyl groups into the resin (i.e. plastics) 1
It is desirable to contain 0.1 to 1700 milliequivalents, preferably 0.2 to 500 milliequivalents, per 00 grams. However, at least the portion (5) of the protective film layer 4 that is in contact with the aluminum layer 3 contains free carboxyl groups of 1% per 100g of resin.
This is not necessarily necessary when the resin contains 1700 milliequivalents.

The amount of free carboxyl groups is 0. ] If it is less than the Mi'J equivalent, the storage stability of the metallic luster will be poor;
The physical properties of such resins pose application difficulties when included in excess of 700 myIJ equivalents.

The base layer 2 is a single resin that satisfies the above physical and chemical conditions,
Or a blend or laminate of these. When the base layer 2 includes a paper material, parchment paper, kraft paper, cellophane, etc., coated on both sides with a resin containing a carboxyl group within the above range, is used. Base layer 2 is
It may be in the form of a film or sheet, or it may be a molded object (
For example, it may be a bottle, a cup, or a can.

The thickness of the aluminum layer 3 needs to be approximately 300-3000X. If it is thinner than about 300X, it will be difficult to form a continuous film and the gas barrier properties will deteriorate.
This is because sufficient metallic luster cannot yet be obtained (6), and on the other hand, even if the thickness is greater than about 3000X, the gas barrier properties are poorly improved, and conversely, material and manufacturing costs increase.

The protective film layer 4 has a function of preventing the aluminum layer 3 formed on the base layer 2 from coming off due to friction or the like.

Therefore, it is desirable that the aluminum layer 3 is made of a strong organic coating, and furthermore, it needs to be made of a coating that maintains the metallic luster of the aluminum layer 3 even when high-temperature water vapor passes through it. In addition, it is desirable that the material has hot water resistance and high temperature steam resistance to the extent that it does not change in quality even when subjected to retort heat sterilization treatment or the like.

Materials that can form such an organic film include low-density polyethylene, high-density polyethylene, polypropylene,
Polyolefin resins such as ethylene-zolopyrene copolymers and ionomers, linear polyester resins, etc. Lyamide resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate resin, ethylene-vinyl acetate copolymer, ABS 8411W, ethylene-vinyl alcohol copolymer/phenol m fat, furan resin, Kinle - Formaldehyde resin, urea resin, melamine resin,
Coumarone indene resin, alkyd resin, thermosetting acrylic resin, epoxy resin, urethane resin, thermosetting polyester resin, unsaturated polyester resin, noaryl phthalate resin, acrolein resin, bismaleimide resin,
Examples include cyclopentane, )x resin, triallyl cyanurate resin, and resins made of combinations thereof.

If at least the portion of the base layer 2 in contact with the aluminum layer 3 is not made of the resin containing 0.1 to 1,700 milliequivalents of free carboxyl groups per 100 grams of resin as described above, at least It is necessary that the portion in contact with the aluminum layer be made of the resin containing 0.1 to 1700 milliequivalents, preferably 0.2 to 500 milliequivalents, of free carboxyl groups per gram of resin.

The reason for this is the same as mentioned above regarding the base layer 2.

The protective film layer 4 is formed by coating, laminating, etc., and its thickness varies depending on the type of resin.
5 to 1000 μm1, more preferably about 2 to 500 μm
It is preferable that it is m. This is because if it is thinner than about 0.5 μm, the protective function is insufficient, and if it is thicker than about 1000 μm, it is not practical.

Aluminum layer 3 forms base layer 2 and/or protective film layer 4
In order to maintain the metallic luster without being affected by the high temperature water vapor that passes through it, the resin containing free carboxyl groups in the above range needs to be in contact with the aluminum layer 3 as described above.

Examples of resins containing free carboxyl groups in the polymer chain include polyester resins having terminal carboxyl groups, or acrylic acid, methacrylic acid, maleic acid, fumaric acid, etc. having carboxyl groups in side chains as a monomer unit. Examples include polymers containing the same.

In addition, aliphatic linear monocarboxylic acids having 4 to 18 carbon atoms such as lauric acid and caproic acid, aliphatic linear monocarboxylic acids such as malonic acid, succinic acid, and maleic acid are added so as to contain free carboxyl groups in an amount within the above range. nocarboxylic acids, and benzoic acid,
Phthalic acid, terephthalate (9) Compounds containing carboxyl groups such as aromatic caldicic acids such as luic acid, salicylic acid, gallic acid, and pyromellitic acid, caldicic acids derived from natural lipids such as dimer fatty acids, polymerized fatty acids, and rosin acid (A) Alternatively, it may be a resin blended with a polymer containing the above-mentioned compound (A), or a polymer (for example, an acrylic acid-based polymer) in which a compound containing a carboxyl group is used as one monomer unit.

In addition, acid anhydrides that generate free carboxyl groups by reacting with other coexisting substances, moisture in the air, or moisture that permeates during retort sterilization, such as maleic anhydride, octylsuccinic anhydride, It may also be a resin blended with phthalic acid, tetrahydrophthalic anhydride, pyromellitic anhydride, derivatives thereof, glutaric anhydride and derivatives thereof, or polymers containing these.

Since the laminate of the present invention contains an appropriate amount of free calgexi groups in the resin of the base layer and/or protective film layer that are in contact with both surfaces of the aluminum layer, the laminate is subjected to retort heat sterilization treatment (for example, 120°C x 30 minutes, or (10) is 145℃ x 3 minutes) or by treatment such as hot water sterilization,
Even if high-temperature water vapor passes through the base layer and the protective film layer, the metallic luster can be maintained.

Since the trench aluminum layer is made of a very thin vapor-deposited metal aluminum layer with a thickness within a predetermined range, it has excellent gas barrier properties, low material and manufacturing costs, and has the advantage of being applicable to molded objects such as bottles. .

Examples will be described below.

Example 1 A metal aluminum layer with a thickness of 500X was deposited on one side 2
Toyobo Copolyester resin [acid value 4.5 KonIn9/#] solution [solid content 10 W] was applied to the vapor deposition surface of a 5 μm biaxially stretched polyethylene terephthalate film.
t%, chloroform (commercially available, special grade) solution] was applied using a percoater, and the solvent was removed in a dry heat oven at 180°C for 5 minutes (coating film thickness after solvent removal was 8 μm) to form a laminate with metallic luster. Manufactured. This laminate was heated to 120°C x 30°C.
Even after being treated with superheated steam for several minutes, the metallic luster was not lost. The oxygen gas permeability of this laminate was measured using an oxygen gas permeability tester oxirane manufactured by Mo-con, and the result was 0.4.
cc7m2. day, atm (at 27°C).

Example 2 Acrylic-epoxy paint manufactured by Toyo Ink Co., Ltd. [acid value 32.6 KOHm9
/, 9, solid content 36 wt%] Coated with a commercially available bar coater and baked in a dry heat oven at 190°C for 12 minutes (
A laminate having a coating film thickness of 7 μm after baking and a metallic luster was produced. This laminate was treated with superheated steam at 120° C. for 30 minutes, but the metallic luster was not lost. The oxygen gas permeability of this laminate is 0.4 cc/m2. day, at
It was m.

Example 3 An epoxy urea resin paint [hard coat] obtained by blending 14.9 parts by weight of Siku P-138 (urea resin) on the vapor deposition surface of the same metal aluminum vapor deposited polyethylene terephthalate film as in Example 1 was applied. Type content 30 wt%, toluene-methyl ethyl ketone equivalent mixed solvent solution], 1.1
5 parts by weight of co-phosphoric acid (commercially available special grade) was added and coated using a percoater.

This film was baked in a dry heat open oven at 200° C. for 12 minutes (coating film thickness after baking was 7 μm) to produce a laminate with metallic luster. A laminate with metallic luster having a composition free of co-phosphoric acid was also produced using the method described above, and the following experiments were conducted.

A laminate of these two types (with and without co-phosphoric acid) was prepared at 120
As a result of superheated steam treatment for 60 minutes at °C, the film coated with the epoxy urea resin paint that does not contain co-phosphoric acid becomes transparent, while the film coated with the epoxy-urea resin paint that contains co-phosphate becomes metallic. The luster was not lost. The oxygen gas permeability of the laminate that did not lose its metallic luster was 0.4cc/m2. day, atm (at
27°C).

Example 4 The same metal aluminum vapor-deposited polyester as in Example 1 (13) On the vapor-deposited surface of the ethylene terephthalate film, 100 parts by weight of an epoxy resin of Epicor 1007 (manufactured by Shell Chemical Co., Ltd.) was mixed with Beckamine P (manufactured by Dainippon Ink Co., Ltd.). -138(
Epoxy urea resin paint (solid content: 30.9 parts by weight) obtained by blending 14.9 parts by weight of urea resin). wt%, toluene-methyl ethyl ketone equivalent mixed solvent solution], 2.2 parts by weight of terephthalic acid (commercially available special grade) was further added and coated using a percoater. 200 yen of this film
C. for 12 minutes in a dry heat oven (coating film thickness after baking: 7 μm) to produce a laminate with metallic luster.

A laminate with metallic luster having a composition free of terephthalic acid was also produced using the above method, and the following experiments were conducted.

A laminate of these two types (with and without terephthalic acid compounded)
As a result of superheated steam treatment at 20°C for 60 minutes, the film coated with epoxy urea resin paint that does not contain terephthalic acid became transparent, while the film coated with epoxy urea resin paint containing terephthalic acid lost its metallic luster. There wasn't.

(14) The oxygen gas permeability of this laminate that did not lose its metallic luster was 0.4 cc/m2. day, atm (at 27
℃).

Example 5 Maleic anhydride-modified polyethylene terephthalate film manufactured by Mitsui Petrochemical Industries, Ltd. was applied to the aluminum-deposited surface of the same aluminum-deposited polyethylene terephthalate film as in Example 1. Lyolefin resin powder ~ NS-100 (trade name) was applied, the upper part was covered with a Teflon sheet, and it was placed between the plates of a hot press at 200°C and heated under pressure at Io kglα for 2 minutes. .

A laminate with a coating thickness of about 6011 m obtained by peeling off the Teflon sheet was boiled in superheated water at 120° C. for 60 minutes, but the metallic luster was barely lost. The oxygen gas permeability of this laminate is 0.4cc/m2. day.

atm (at 27°C).

[Brief explanation of the drawing]

The figure is a longitudinal cross-sectional view of a laminate that is an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Laminate, 2... Base layer, 3... Metal aluminum layer, 4... Protective film layer.

Claims (1)

[Claims] (1) A laminate in which a vapor-deposited metal aluminum layer with a thickness of about 300 to 3000X is entirely formed on a base layer mainly made of plastics or paper, and a protective film layer is formed on the metal aluminum layer. At least the portion of the base layer and/or the protective film layer that is in contact with the aluminum layer,
Free carboxyl groups from 0.1 to 100 grams of resin
A laminate comprising an Al layer containing 1700 milliequivalents of the resin.