JP3260907B2 - Metal / resin laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to toothpastes, pharmaceuticals,
The present invention relates to a metal / resin laminate suitable for container packaging materials such as cosmetics and chemical materials.

[0002]

2. Description of the Related Art Conventionally, a metal thin film such as an aluminum foil and a polyolefin resin layer have been bonded by ethylene- (meth)
Acrylic acid copolymer resin is used (Latest Handbook of Laminating Processing Technology Processing Technology Research Association, published on June 30, 1989, JP-A-3-153346).

[0003] This laminate is widely used in the above-mentioned various packaging tubes, taking advantage of the excellent gas barrier properties, light shielding properties, aesthetics, and the like of aluminum. However, when this laminated tube is used as a toothpaste container and a container for medicines, components such as peppermint and spearmint contained in toothpaste and menthol and salicylic acid contained in medicines and the like contain polyolefin resin layer and ethylene- ( The adhesive strength with the (meth) acrylic acid copolymer resin layer is remarkably reduced, and delamination occurs as time elapses, so that there is a defect that the toothpaste inside is leaked from the laminate tube.

Further, when the above-mentioned ethylene- (meth) acrylic acid copolymer resin contains a color masterbatch containing a coloring agent such as titanium oxide and carbon black, the influence of the coloring agent itself and the above-mentioned ethylene- (meth) acrylate ) Due to the compatibility of the acrylic acid copolymer resin with the base resin of the masterbatch and the effects of additives such as dispersants contained in the masterbatch, the metal thin film and the ethylene- (meth) acrylic acid copolymer resin The adhesive strength with the layer is weakened, and the adhesive strength between the polyolefin-based layer and the ethylene- (meth) acrylic acid copolymer resin layer due to the fragrance of the contents is further promoted.

[0005]

DISCLOSURE OF THE INVENTION The present invention has practically sufficient adhesive strength when packaging toothpastes containing fragrances and the like, and pharmaceuticals containing components such as menthol and methyl salicylate. An object of the present invention is to provide a metal / resin laminate that gives a raw material for a laminated tube.

[0006]

The present invention relates to a method for preparing a polyolefin resin base material layer (A) having a surface selected from (a) 82 to 98.9 mol% of ethylene, (b) acrylic acid and methacrylic acid. 1 to 9 mol% of α, β-unsaturated carboxylic acid
And (c) a copolymer of 0.1 to 13 mol% of an acrylate selected from lower alkyl acrylates and lower alkyl methacrylates (provided that the lower alkyl group has 1, 2 or 4 carbon atoms). A metal / resin laminate provided with an adhesive layer (B) of an ethylene copolymer and a thin metal layer (C) provided on the surface of the adhesive layer (B). It is.

[0007]

The carboxyl group of the adhesive layer (B) improves the adhesive strength to the metal thin film, and the ethylene copolymer of the adhesive layer contains (meth) acrylate as a copolymer component. (Meth) whose melting point of the polymer is the same mol%
Binary ethylene having acrylic acid as a copolymer component
Since the copolymer (B) has a lower flexibility than the melting point of the (meth) acrylic acid copolymer and is more flexible, the adhesion to the metal thin film is improved as compared with the conventional binary copolymer adhesive layer. And
Further, the decrease in the adhesive strength with time with the polyolefin resin layer is small.

(Specific Description of the Invention) Polyolefin Resin Base Material Layer (A) The polyolefin resin constituting the base material layer (A) of the present invention includes ethylene, propylene, α having 4 to 8 carbon atoms.
An olefin homopolymer or a copolymer of two or more of these, ethylene or propylene as a main component, and vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylic acid lower alkyl ester (alkyl group having carbon atoms) Are obtained by copolymerizing vinyl monomers selected from lower alkyl esters of methacrylic acid (alkyl groups having 1 to 3 carbon atoms), crosslinked products thereof, and acrylic resins And those modified by grafting with maleic anhydride, styrene, and the like.

Specific examples include the following.
Low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-
Butene-1 copolymer, poly (butene-1), propylene homopolymer, crystalline propylene-α-olefin copolymer, styrene graft-modified polypropylene resin, styrene graft-modified polyethylene resin, maleic anhydride-grafted polypropylene, maleic anhydride Graft polyethylene, ethylene-vinyl acetate copolymer, ethylene-
(Meth) acrylic acid copolymer or its metal salt, poly (4-methylpentene-1), ethylene- (meth) acrylic acid alkyl ester copolymer, vinyl chloride-propylene copolymer, vinylsilane crosslinked polyethylene.

[0010] Among these, the melt flow rate (J
Ethylene resins such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene having an IS K-7211 of 0.5 to 50 g / 10 min are preferable. The thickness of the polyolefin resin layer is 10 to
200 μm is common.

Adhesive layer (B) The ethylene copolymer used as an adhesive layer between the polyolefin resin (A) and the metal thin film (C) is (a) 82 to 98.9 mol% of ethylene, preferably 90 to 95 mol%. Mol%, (b) α, selected from acrylic acid and methacrylic acid,
β-unsaturated carboxylic acid 1 to 9 mol%, preferably 2 to 7 mol%
Mole% and (c) a lower alkyl acrylate,
Ethylene series obtained by copolymerizing 0.1 to 13 mol%, preferably 3 to 8 mol% of an acrylate selected from methacrylic acid lower alkyl esters (however, the number of carbon atoms of the lower alkyl group is 1, 2 or 4) It is a copolymer. Melt flow rate of ethylene copolymer (190 ° C., 2.16
kg load) 0.3 to 50 g / 10 min, preferably 3 to 50 g / 10 min.
The melting temperature is 15 g / 10 min, and the melting end temperature is 80 to 115 ° C, preferably 85 to 110 ° C.

More specifically, ethylene-acrylic acid-methyl acrylate copolymer, ethylene-acrylic acid-ethyl acrylate copolymer, ethylene-acrylic acid-n-butyl acrylate copolymer, ethylene-acrylic acid -Methyl methacrylate copolymer, ethylene-acrylic acid-ethyl methacrylate copolymer, ethylene-acrylic acid-n-butyl methacrylate copolymer, ethylene-acrylic acid sodium salt-methyl acrylate copolymer, ethylene- Sodium acrylate-ethyl acrylate copolymer, ethylene-sodium acrylate-n-butyl acrylate copolymer, ethylene-sodium acrylate-methyl methacrylate copolymer, ethylene-sodium acrylate-methacrylic Ethyl acid copolymer, ethylene-acrylic acid sodium salt Methacrylate n- butyl copolymer,
Ethylene-zinc acrylate-methyl acrylate copolymer, ethylene-zinc acrylate-ethyl acrylate copolymer, ethylene-zinc acrylate-n-acrylate
Butyl copolymer, ethylene-zinc acrylate-methyl methacrylate copolymer, ethylene-zinc acrylate-
Ethyl methacrylate copolymer, ethylene-zinc acrylate-n-butyl methacrylate copolymer, ethylene-methacrylic acid-methyl acrylate copolymer, ethylene-methacrylic acid-ethyl acrylate copolymer, ethylene-methacryl Acid-n-butyl acrylate copolymer, ethylene-methacrylic acid-methyl methacrylate copolymer, ethylene-methacrylic acid-ethyl methacrylate copolymer, ethylene-methacrylic acid-n-butyl methacrylate copolymer, ethylene -Sodium methacrylate-methyl acrylate copolymer, ethylene-sodium methacrylate-ethyl acrylate copolymer, ethylene-sodium methacrylate-n-butyl acrylate copolymer, ethylene-sodium methacrylate- Methyl methacrylate copolymer, ethylene- Methacrylic acid sodium salt - ethyl methacrylate copolymer, ethylene - methacrylic acid sodium salt - methacrylate n- butyl copolymer, ethylene -
Zinc methacrylate-methyl acrylate copolymer, ethylene-zinc methacrylate-ethyl acrylate copolymer, ethylene-zinc methacrylate-n-butyl acrylate copolymer, ethylene-zinc methacrylate-methacrylic Methyl acrylate copolymer, ethylene-zinc methacrylate-ethyl methacrylate copolymer, ethylene-zinc methacrylate-n-butyl methacrylate copolymer, and the like.

If the constituent unit based on ethylene (a) of the ethylene copolymer is less than 82 mol%, it is difficult to produce the copolymer itself, and if it exceeds 98.9 mol%, the adhesive strength to the metal thin film is low. Inferior. Constituent unit based on (b) (meth) acrylic acid of ethylene copolymer is 1 mol%
, Less than 9 mol%, and less than 0.1 mol% or more than 13 mol% of the constituent unit based on (c) the lower alkyl (meth) acrylate, the adhesive strength to the metal thin film is inferior. And (b) (meta)
Acrylic acid is more than 9 mol%, and (c) the lower alkyl (meth) acrylate is less than 0.1 mol%,
In any case exceeding 3 mol%, the adhesive strength to the polyolefin-based resin layer is inferior.

Further, the melt flow rate is 0.3 g / 1.
If the time is less than 0 minutes, the workability is inferior because the spreadability is poor.
If the time exceeds 10 minutes, the neck-in becomes large and the workability is poor. If the melting point is less than 80 ° C, the heat resistance is inferior and 115 ° C
Exceeding the adhesive strength to the metal thin film and the polyolefin resin layer is inferior. If necessary, the ethylene copolymer layer is made of titanium oxide, carbon black, zinc oxide, iron oxide, calcium carbonate, silica, chromium oxide,
20% by weight of coloring agents generally used for thermoplastic resins, such as inorganic pigments such as talc, organic pigments such as phthalocyanine, anthraquinone, quinacridone, azo, quinaphthalone, perinone and perylene, and dyes. The following may be contained. This coloring agent may be blended as a master batch containing 5-45% by weight of an ethylene resin described below.

As the base resin when this colorant is used as a masterbatch, any resin can be used as long as it can be mixed with the above-mentioned ethylene copolymer resin as the component (B). No. The ethylene resin and the melt flow rate of the component (B) described above (JIS K
-7211) is 0.5 to 70 g / 10 min of low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene- (meth) acrylic acid copolymer, and an additive for a masterbatch A lubricant is used in an amount of several percent by weight or less in order to improve the uniform mixing of the colorant and to lower the friction coefficient with respect to a processing machine. For example, an oleamide amide lubricant, an erucamide amide lubricant, a stearamide amide lubricant is used. And stearic acid-based metal soaps. Plasticizers as other additives,
A heat stabilizer, a flame retardant, a deterioration inhibitor, a coupling agent, and the like may be contained in an amount of several percent by weight or less. The thickness of the adhesive layer (B) is generally 3 to 200 μm, preferably 10 to 150 μm.

Metal thin film (C) A metal thin film is a foil of metal such as aluminum, copper, silver and gold having a thickness of 5 to 250 μm, polyethylene, polypropylene, polyethylene terephthalate, polyamide, polystyrene, polycarbonate, polyvinyl chloride and the like. On a surface of a base material such as a thermoplastic resin film or paper, a metal deposition film having a thickness of usually about 100 to 1000 Å is formed by a known deposition method such as a vacuum deposition method, a sputtering method, and an ion beam method. Can be used.

Laminate The laminate of the present invention comprises a polyolefin resin base material layer (A)
Extrusion lamination of the above-mentioned ethylene copolymer resin (B) between the metal thin film (C) and the metal thin film (C)
Then, the above-mentioned ethylene-based copolymer resin (B) and polyolefin-based resin layer (A) are co-extruded and laminated by a known method.

At this time, the temperature of the ethylene copolymer resin is usually set to 150 to 330 ° C. immediately below the die.
The temperature is preferably 20 to 310 ° C. If the temperature of the copolymer is lower than 150 ° C., not only the spreadability is poor and smooth melt extrusion cannot be performed, but also the adhesive strength with the polyolefin resin layer or the metal thin film cannot be obtained. On the other hand, when the temperature exceeds 330 ° C., decomposition of the copolymer tends to occur.
When the metal thin film is a vapor-deposited film, if the temperature exceeds 290 ° C., problems such as generation of fine cracks in the vapor-deposited film are likely to occur, so the extrusion lamination temperature of the copolymer (B) is 290 ° C. or less. It is preferred that

In the present invention, when the above-mentioned ethylene copolymer resin (B) is extrusion-laminated on a metal thin film,
If the surface to be laminated of the metal thin film is subjected to corona treatment in advance, the adhesive strength with the metal thin film is further improved (Japanese Patent Laid-Open No. 62-44).
No. 20). In extrusion laminating the ethylene copolymer resin between the metal thin film and the polyolefin resin base material layer, the surface to be laminated of the polyolefin resin base material layer is subjected to corona treatment in advance, so that the polyolefin resin base material layer and Is further improved in adhesive strength.

At this time, the corona-treated surface of the thin metal film is preheated to 100 ° C. to 180 ° C., or the surface to be laminated of the polyolefin resin base material layer is preheated to 40 ° C. to 80 ° C .; Anchor coating gives particularly favorable results in the present invention. The laminate of the present invention has a polyolefin-based substrate layer (A) of 10 to 20.
An adhesive layer (B) of an ethylene copolymer on a surface of 0 μm
200 μm, preferably 10-150 μm is provided,
Further, a thin metal layer (C) is provided on the surface of the adhesive layer (B). This laminate is a metal / resin laminate suitable as a container and packaging film for toothpastes, pharmaceuticals, cosmetics, chemical materials, etc. Even when used for toothpastes, packaging of pharmaceuticals, etc., the quality of the packaged objects deteriorates, leaks, etc. Is not likely to occur.

[0021]

【Example】

Examples 1 to 9 Comparative Examples 1 to 6 Aluminum foil (JIS A1N30H) having a thickness of 40 μm
-O) as one substrate, and a linear low-density polyethylene film (LLDPE-1 MFR: 90 .mu.m) having a thickness of 90 .mu.m.
8 g / 10 min. Density: 0.926 g / cm ³ ) was used as the other base material, and both base materials were unwound from an unwinder. The resin shown in Table 1 was used as the ethylene copolymer resin for the adhesive layer. Has a resin temperature of 28 from a T-die mounted on a 90 mm extruder.
At 0 ° C., the two substrates are melt-extruded and laminated by pressure bonding.
Aluminum / Ethylene copolymer resin / LLDPE-
Thus, a three-layer laminate of No. 1 was produced. The laminating speed at this time was 30 m / min, and the thickness of the ethylene copolymer resin was 7 m / min.
The thickness was 5 μm.

The adhesive strength between the obtained aluminum foil of the metal / resin laminate having a thickness of 205 μm and the ethylene-based copolymer resin, and the adhesive strength between the LLDPE-1 film and the ethylene-based copolymer resin were measured for toothpaste. The results were measured before immersion and after immersion in a toothpaste at 49 ° C. for 2 weeks.
It was shown to.

[0023]

[Table 1]

Example 10, Comparative Example 7 Instead of the LLDPE-1 film, a linear low-density polyethylene film (LLDPE-2 MFR: 4.5 g /
10 minutes, density: 0.934 g / cm ³ )
The resins shown in Table 2 were used as the ethylene-based copolymer resin, and the corona discharge treatment was performed using aluminum foil and L.
Except that 50 (W · min / m ² ) was applied to the surface to be laminated of the LDPE-2 film, a metal / resin laminate was manufactured in the same manner as in Example 1, and the adhesive strength before and after immersion in toothpaste was measured. The results are shown in Table 2.

Example 11 Comparative Example 8 A metal / resin laminate was prepared in the same manner as in Example 10 except that a mixture of an ethylene copolymer resin and a color master batch shown in Table 2 was used as the ethylene copolymer resin. The adhesive strength before and after immersion in the toothpaste was measured, and the results are shown in Table 2.

Examples 12 to 13 Comparative Examples 9 to 10 An LDPE-1 film was used in place of the LLDPE-2 film, and an ethylene copolymer resin and a color masterbatch shown in Table 2 were used as the ethylene copolymer resin. Except for using the mixture, a metal / resin laminate was manufactured in the same manner as in Example 10, and the adhesive strength before and after immersion in toothpaste was measured. The results are shown in Table 2.

The adhesive strength was measured by cutting a metal / resin laminate into a test piece having a width of 15 mm and a length of 80 mm in parallel with the laminating direction, collecting the test piece before and after immersing it in toothpaste, and peeling the test piece. It is represented by the maximum strength measured at a speed of 100 mm / min and T-peel peeling.
The value of the adhesive strength required for practical use was 650 g for each layer.
/ 15 mm and the judgment was made.

[0028]

[Table 2]

[0029]

According to the present invention, there is obtained a laminate in which the adhesive strength between metal and polyolefin resin layers due to fragrance components such as fragrance, methyl salicylate, and menthol in the articles to be stored is reduced with time.

Continuation of the front page (56) References JP-A-3-153346 (JP, A) JP-A-48-26280 (JP, A) JP-A-60-40136 (JP, A) JP-A-2-103321 (JP, A) , A) Hikaru 4-63236 (JP, U)

Claims (2)

(57) [Claims] 1. An α, β-unsaturated carboxylic acid selected from (a) 82 to 98.9 mol% of ethylene and (b) acrylic acid or methacrylic acid on the surface of a polyolefin resin base material layer (A). 1 to 9 mol% and (c) 0.1 to 13 mol% of an acrylate selected from lower alkyl acrylates and lower alkyl methacrylates (the lower alkyl group having 1, 2 or 4 carbon atoms). An adhesive layer (B) of an ethylene copolymer obtained by polymerization is provided,
A metal / resin laminate, further comprising a thin metal layer (C) provided on the surface of the adhesive layer (B). 2. An ethylene copolymer having a melt flow rate (190 ° C., 2.16 kg load) of 0.3 to 50 g /
The melting end temperature is 80 to 115 ° C for 10 minutes.
2. The metal / resin laminate according to item 1.