JPH04131236A - Laminated, lid material and container - Google Patents

Abstract

PURPOSE:To enhance easy opening properties by constituting a laminate of a layer of a composition consisting of an ethylene/vinyl alcohol copolymer and polyolefin and a layer of a composition composed of an isocyanate-urethane compound. CONSTITUTION:A laminate consisting of a layer of a composition A consisting of an ethylene/vinyl alcohol copolymer (EVOH) and polyolefin (PO) and a layer of a composition B composed of an isocyanate-urethane compound is used as a lid material or a container main body and the B-layer is set to a seal layer. As EVOH, a saponified ethylene/vinyl acetate copolymer is used and, as PO, a homopolymer of olefin such as ethylene, propylene, butene or pentence, a copolymer consisting of two or more kinds of olefins or a copolymer of olefin and one or more kind of other copolymerizable monomer is designated. By this method, an inexpensive laminate, a lid material and a container excellent in easy opening properties, the preservability of content and see-through can be obtained.

Description

[Detailed Description of the Invention] A. Industrial 1. The present invention has excellent ease of opening, preservation of contents, and transparency;
The present invention also relates to an inexpensive laminate, lid, and container.

B. Prior Art Many easy-to-open lids have been introduced in the past, but there are still not enough easy-to-open lids that have the contradictory characteristics of having sufficient adhesion during transportation and being easy to open. There has been a long-awaited desire to develop an easy-to-open lid material that has both these properties and excellent transparency.

In order to satisfy both easy-openability and gas barrier properties, it is necessary to laminate a resin with easy-openability and a resin or foil with gas barrier properties. There is a desire for cost reduction.

C Problems to be Solved by the Invention The present invention aims to solve the above-mentioned problems of ease of opening, preservation of contents, transparency, and cost all at once.

D Second Means for Solving the Problem The present invention provides a layer of composition (A) consisting of an ethylene-hinyl alcohol copolymer (hereinafter referred to as EVOH) and a polyolefin (hereinafter referred to as PO), Composition (B
) is used as the lid material, or such a laminate is used for the container body, and each of the layers (B
) layer is a sealing layer.

As (A)Fi in the present invention, a composition consisting of EVOH and PO is used.

A typical example of such EVOH is a saponified ethylene-hinyl acetate copolymer, the ethylene content of which is preferably 10 to 70 mol%, particularly preferably 20 to 65 mol%, and the degree of saponification is 85% or more. , especially preferably 95% or more).

If the ethylene content is lowered to 10 mol% or if the degree of saponification is lower than 85%, the gas barrier properties at high humidity will be poor, and if mixed with PO and melt-molded, it will become a gel. It generates deterioration products such as linoleum and is poor in ease of opening, making it impossible to obtain products with commercial value. Also, the ethylene content is 7
If it exceeds 0 mol %, the gas barrier properties will be poor regardless of whether the humidity is low or high, and the ease of opening will be poor.

Possible POs include homopolymers of olefins such as ethylene, propylene, butene, pentene, 4-methyl-1-pentene, hexene, and octene, copolymers of two or more olefins, or copolymers of olefins and other copolymers. Examples include copolymers of one or more polymerizable monomers, including low-density, high-density, linear low-density polyethylene, etc., and also include blends of these copolymers.

Examples of copolymers include ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylate copolymer, and ionomer. Examples include ethylene-pentene copolymers and ethylene-octene copolymers.

In the present invention, it is preferable to use a carboxylic acid-modified PO as PO in order to impart appropriate ease of opening and transparency.

The carbonic acid referred to in the present invention refers to unsaturated carbonic acids such as maleic acid, itaconic acid, and acrylic acid, unsaturated polycarboxylic acids, or their acid anhydrides, salts, esters,
refers to amides, imides, etc., and not only free carboxylic acids,
This includes derivatives thereof.

The method for producing such carbonic acid-modified PO is to copolymerize olefin and carbonic acid and copolymerize carboxylic acid in the main chain, or to graft-modify the PO with carbonic acid and copolymerize carboxylic acid in the side chain. In the present invention, it is particularly preferable to graft-modify at least one monomer selected from the group consisting of carbonic acids and use 7:PO because it provides easy opening and transparency.゜The carboxylic acid modification rate of the carboxylic acid modified PO is in the range of 10-' to 5% by weight in the case of carbonic acid kraft-modified PO, and in the range of 3 to 50% by weight in the case of the olefin-carboxylic acid copolymer. It is preferable for achieving the purpose.

If the carbonic acid modification rate is below or above the above value, the ease of opening will be poor.
When mixed with OH to form layer (A), the transparency is poor.

It is also possible to use a mixture of carboxylic acid-modified PO and unmodified PO.

(A) The blending ratio of EVOH and PO constituting the layer is EV
The preferred range is 95 to 50% by weight of OH and 5 to 50% by weight of PO. When the amount of EVOH is less than the 50-fold form,
Gas barrier properties and ease of opening are poor, and when the blending amount of EVOH exceeds 95% by weight, gas barrier properties are excellent but ease of opening is poor.

When the cross section of the film etc. is observed, the composition (A) consisting of EVOH and PO of the present invention shows that the EVOH is the sea.
A structure in which PO is an island is preferable in terms of obtaining good ease of opening and good gas barrier properties.

To make EVOH an ocean and PO an island, EV
Select the blending ratio of OH and PO from the above range, and
Examples include a method of sufficiently melt-kneading V OH and PO, such as a method of melt-kneading using a twin-screw extruder or the like.

As the layer (B) of the present invention, a composition comprising a vinyl chloride polymer and a urethane-isonoanate compound is used.

Examples of such vinyl chloride-based polymers include, in addition to polyvinyl chloride, copolymers of vinyl chloride containing 50% by weight or more of vinyl chloride and one or more other copolymerizable monomers, such as polyvinyl chloride. Vinyl chloride-vinyl acetate copolymer containing more than % by weight of vinyl chloride or vinyl chloride-vinyl acetate-carphonic acid copolymer, specifically vinyl chloride-hinyl acetate-(anhydrous) maleic acid copolymer, chloride Examples include vinyl-vinyl acetate-(meth)acrylic acid copolymer.

In particular, as a vinyl chloride copolymer, vinyl chloride 55-9
8% by weight, preferably 70-95% by weight and vinyl acetate and/or carbonic acid by weight of 45-2% by weight.
, preferably 30 to 5% by weight, is suitably used for the purpose of the present invention, and in particular, the use of vinyl chloride-hinyl acetate-carboxylic acid copolymer is most preferred for achieving the purpose of the present invention.

Further, the vinyl chloride polymer graft-modified with carboxylic acid is also preferable in order to prevent blockage between the laminates.

In the present invention, two or more types of vinyl chloride polymers may be used in combination.

In addition, the previous g2 EV OH has excellent gas barrier properties and is suitable for use in preserving foods, etc., or is a combination of such EVOH, the vinyl chloride polymer, and the urethane-isocyanate compound according to the present application. Composition (B
), it was found that the preservability of the contents of foods, etc., was even more significantly improved when used in combination with

In the second case, it has been found that the preservation performance is even more pronounced when exposed to sunlight, reflected sunlight, ultraviolet rays, or fluorescent lamp light. Such an effect cannot be explained simply by the gas barrier property of the material, and although its mechanism is not clear, it can be said to be a noteworthy effect of the present invention.

The isocyanate-urethane compound as used in the present invention refers to a compound having an isocyanate group and/or a urethane group in the molecule.

Here, the term "compound" includes not only low-molecular compounds but also high-molecular compounds, that is, polymers.

Such utarene groups are mainly obtained by the reaction of isocyanate groups and active hydrogen, and compounds having only urethane groups produced by the reaction of such isocyanate groups and active hydrogen are also included in the isocyanate-urethane compounds referred to in the present invention. It will be done.

However, it is preferable for the isocyanate group to exist until the layers (A) and (B) are laminated, since this provides better unsealability.

However, after layer (A) and layer (B) are laminated, there is no problem even if the layer reacts with a compound having active hydrogen such as moisture in the air to form a urethane group.

Examples of the iso-soanate-urethane compounds referred to in the present invention include the "Latest Lamination Processing Handbook" (June 3, 1989).
0, published by the Processing Technology Research Group) are used.

In the present invention, a composition of the vinyl chloride polymer and an isocyanate-urethane compound is used as the layer (B), and the blending ratio is 100 parts of the vinyl chloride polymer.
0.0 isocyanate-urethane compound per part by weight
It is preferable to blend in a proportion of 1 to 70 parts by weight, preferably 0.1 to 50 parts by weight, since it provides good ease of opening, transparency, and anti-blocking properties.

Here, the amount of isonoanate-urethane compound is:
If there are many active isocyanate groups in the compound, it is better to blend a relatively small amount within the range of the above blending ratio, and if there are few active isocyanate groups in the compound,
A relatively large amount within the range of the above-mentioned mixing ratios provides a better balance of the effects of easy-opening, transparency, and anti-blocking properties.

In the present invention, two or more types of urethane-isonanate compounds can also be used in combination.

In addition, since isocyanate-urethane compounds are easily deteriorated by heat, the composition (B) according to the present invention is not used as the composition (A).
For laminating into layers, composition (B) is dissolved in a solvent and (
^) coating method is recommended.

Examples of the solvent for composition (B) include methyl ethyl ketone, methyl butyl ketone, acetone, methyl acetate, ethyl acetate,
Examples include organic solvents such as butyl acetate, toluene, and THF, and it is also preferable to use a mixed solvent of these organic solvents in order to form a homogeneous coating film.

Since dioctyl phthalate (DOP) and dibutyl phthalate (DBP) can serve as plasticizers or solvents for the composition (B), they are used in combination with other low-boiling point organic solvents and left in the composition (B) after drying the coach-ingle. , composition (B)
It can also provide flexibility.

In the present invention, a laminate having the structure (C)/(A)/(B) consisting of the base material (C) and the layers (A) and (B) described above is used for lid materials, molded containers, sealed containers, etc. However, examples of the base material (C) include thermoplastic resins, metal-deposited thermoplastic resins, metal foils, and glass.

Examples of such thermoplastic resins include polyolefins such as polypropylene and polyethylene, polyesters such as polyethylene terephthalate, nylon-6, and nylon-6,6.
, polyamides such as copolymers of nylon-6 and 66, polycarbonates, polystyrene, polyvinyl chloride, polyacrylonitrile, etc., and such thermoplastic resins are uniaxially or biaxially stretched for good ease of opening. sex,
Excellent in terms of printability and aesthetics.

Further, as an example of metal vapor deposition, aluminum vapor deposition is excellent, and as a metal foil, aluminum foil is excellent in terms of cost and aesthetics.

In addition, in order to laminate the base materials (C) and (A), a known lamination method such as a dry lamination method, an extrusion lamination method,
Coextrusion lamination method etc. are adopted.

When laminating (C) and (A) by a dry lamination method, it is preferable to use an isocyanate-urethane adhesive in order to obtain sufficient adhesive strength.
) and (^) by coextrusion method or extrusion lamination method, if sufficient adhesive strength cannot be obtained between (C) and (A), adhesive strength between (C) and (A) may not be obtained. A method using a synthetic polymer is recommended.

In addition, as for the lamination procedure, (B) may be laminated after (C) and (^) are laminated, or (C) may be laminated after (^) and (B) are laminated. The order of lamination may be selected as appropriate.

As mentioned above, the base material (C) is preferably a pongee or biaxially stretched material, so lamination of (C) and (A) or (C)
(A)/(B) can be laminated by dry laminating using an adhesive, or by applying an anchor coat to the stretched base material (C) and extrusion laminating (A). Recommended.

It is also possible to print on the front or back side of the base material (C).
It is useful for enhancing aesthetic appearance and product value.

In addition, in the present invention, other thermoplastic resins and various additives such as colorants, heat stabilizers,
Ultraviolet absorbers, slip agents, plasticizers, etc. can also be added depending on the purpose.

In the present invention, the container is sealed with the lid material to form a hermetically sealed container. Examples of the container include a thermoformed container such as a vacuum molded pressure container made of thermoplastic resin, a blow molded container, an injection molded container, etc. Examples of thermoplastic resins constituting such containers include polyesters such as polyethylene terephthalate, polyolefins such as polycarbonate, polyvinyl chloride, polyacrylonitrile, polyamide, polystyrene, polypropylene, and polyethylene.

Such a container can be made into a multilayer container by combining two or more types of thermoplastic resins, if necessary.

Since the lid material according to the present invention has excellent gas barrier properties, it is preferable to use a resin having excellent gas barrier properties for such containers as well, in order to improve the gas barrier properties of the sealed container.

In particular, the sealing surface of the container according to the present invention with the lid material includes:
It is particularly preferable to use polyester such as polyethylene terephthalate, polyvinyl chloride, polyacrylonitrile, and polycarbonate in order to achieve the objects of the present invention such as easy opening.

In the present invention, the structure of the lid material (see FIG. 1) can also be used for the container body as shown in FIG. 2.

The easy-to-open laminate and container according to the present invention can be used for food packaging, industrial parts packaging such as carrier cases for ICs, etc.
It is useful for packaging pharmaceutical tablets and powders.

Examples of the present invention will be shown below.

The evaluation method is as follows.

(1) Ease of opening The lid material of the sealed container was opened, and the ease of opening, the feel when opening, and the aesthetic appearance of the unsealed surface were judged by a panel of 10 people, and the average values were taken.

■ and l:m Filled with miso, sealed, f2 container packed in cardboard, transported by truck from Osaka to Tokyo, then transferred to another truck, and observed the peeling state of the seal surface when transported from Tokyo to Osaka. , the ratio of peeled samples to the number of samples subjected to transportation is expressed as a percentage.

(3) After filling the container with miso and sealing it, leave it for 90 days indoors near a window on the south side of the room, where it will not be exposed to direct sunlight but will receive plenty of reflected light.

The food is then opened, and the color tone, texture, and taste of the food are evaluated by a panel of 10 people, and the average value is taken.

■2LL After filling with miso, the miso inside the container was seen through the C/A/B layer part of the container, and 10 panelists evaluated the transparency.
Judgment is made and the average value is taken. In the case of a comparative example, the same determination is made by looking through the corresponding portion.

However, items (1), (3), and (4) were evaluated based on the following criteria.

◎ mark: Very good, O mark: Good, △ mark: Slightly poor, × mark: Poor L"15 Example I Ethylene content 44 mol%, degree of saponification 995%, melt index (M r ) 5.5g/10 minutes (19
75 parts by weight of EVOH (E-1,) pellets (added 160 g of 06C12) and maleic anhydride graft modified (modification rate 0.5% by weight) high density polyethylene M I 0.3 (P
(11) 25 parts by weight of pellets were fed into an extruder with twin screws (same direction twin screw extruder 65 m/mφ, L/D=3
0), a temperature of 210℃ and a temperature of 200℃.
The mixture was sufficiently melted and kneaded at "C", extruded into strands, cut into pellets, and made into a composition (A).

This pellet was put into an extruder having a 90 m/lφ, L/D=28 full-flight screw, and melt-extruded using the T-die method at an extruder cylinder temperature of 210°C and a T-die temperature of 200°C to obtain a flat sheet with a thickness of 15 μm. Got the film.

This film was cut with a razor, and the cut film pieces were immersed in an alcoholic iodine solution in which only EVOH was stained. After washing with water and observing the cut surface of the film with a microscope, maleic anhydride was found in the sea of EVOH. It was confirmed that modified high-density polyethylene existed in the form of islands.

Next, on one side of the film, a vinyl chloride-vinyl acetate-maleic acid copolymer (VC-1) containing 85% by weight of vinyl chloride, 14% by weight of vinyl acetate and 1% by weight of maleic acid was used as a vinyl chloride-based polymer, Isocyanate
Dainippon Ink & Chemicals Co., Ltd. K as a urethane compound
Using P-90 (I U-1), 99.5 parts by weight of vinyl chloride-vinyl acetate-maleic acid copolymer and K P-
Using a toluene/methyl ethyl ketone = 1/+ (weight) solution with a solid content concentration of 20% by weight of Formulation (B) containing 0.5 parts by weight of 90, the coating amount was 3.0 g/m'' (based on solid content).
Coat with a gravure coater at a temperature of 100
℃! Dry for a minute.

Next, two-wheel stretched polyethylene terephthalate (P
ET) film (C) (Toyo Shiku Co., Ltd. Lumirror 12μ) with 2.5 g/m of isocyanate-urethane adhesive (AD-570A/CAT-10) manufactured by Toyo Morton Co., Ltd.
'c solid content basis) was coated and dry laminated in a conventional manner at a temperature of 60°C to produce a laminate consisting of (C)/(A)/(B).

Next, a container vacuum-formed from a hard polyhinyl chloride sheet with a thickness of 700 μm was filled with miso, and then the opening of the container was sealed by heat sealing.

The evaluation results are shown in Table-1.

On the other hand, using a laminate that does not satisfy the constituent requirements of the present invention,
Evaluation results for sealed containers filled with miso are also shown in Table 1 as a comparative example.

Example 2 Ethylene content 32 mol%, saponification degree 99.6 mol%,
M! 1.3g/10min EVOH (E-2) grip,
T) 80 parts by weight of M I 1.0 g/10 minutes of maleic anhydride graft modification (modification amount 1.0 wt%) polypropylene (PO-2) pellets 20 tm were thoroughly melt-kneaded in the same manner as in Example 1. The mixture was pelletized to produce a composition (A).

A tubular film was formed from this pellet using an isofure film forming apparatus, and after folding the tubular film, both ears were cut to obtain a flat film with a thickness of 20 μm. This film was processed in the same manner as in Example 1. When I looked at the cross section of the film, I confirmed that it was a sea of EVOH, and that there were islands of modified polypropylene.

Next, one side of the film was coated with MPR-TM (vinyl chloride 86% by weight, vinyl acetate 13% by weight - maleic anhydride 1%) manufactured by Nissin Chemical Industry Co., Ltd. as a vinyl chloride polymer.
% by weight of copolymer, VC-2), A D manufactured by Toyo Morton Co., Ltd. as an isonoanate-urethane compound
-335A and CAT-10505 (IU-2), MPR-TM and
D-335A/CT A-10 75/25 (
(parts by weight) of formulation (B) at a concentration of 15% by weight toluene/
Methyl ethyl ketone-1/2 (1) was coated using a solution at a coating amount of 2.5 g/m' (based on solid content),
Dry.

Biaxially oriented polypropylene (PP) film (Toyobo Co., Ltd.
Isocyanate-urethane adhesive manufactured by Dainippon Ink and Chemicals Co., Ltd.
Dry lamination L (C)/
A laminate consisting of (A)/(B) was made.

Next, a vacuum-formed container made of polyethylene terephthalate having a thickness of 500 μm was filled with miso, and then the opening of the container was sealed by heat sealing.

The test results are shown in Table-1.

Example 3 Ethylene content 38 mol%, saponification degree 99.5%, Ml
1, 90 parts by weight of 6 g/10 min EVOH (E-3) pellets and maleic anhydride graft modification (modified amount 0.1% by weight) ethylene-vinyl acetate copolymer (vinyl acetate 5% by weight) (PO-3 ) 10 parts by weight in a co-directional twin-screw extruder (65
s/mφ, L/D=30), cylinder temperature 2
The composition was sufficiently melted and kneaded at 20°C and a Gui temperature of 210°C, extruded into strands, and cut into pellets (
^) I made it.

Such a composition (^), adhesive polypropylene (Q F 500 manufactured by Mitsui Petrochemical Industries) and polypropylene (C) (
Mitsubishi Yuka MA-6) (A) 20μ/adhesive bobbin σ
A sheet was prepared by coextruding a composition of pyrene IQμ/polypropylene (C) 501)μ.

Next, on the (A) side of the sort, a vinyl chloride-vinyl acetate-acrylic acid copolymer (VC-3) containing 90% by weight of vinyl chloride, 7% by weight of vinyl acetate, and 3% by weight of acrylic acid was used as a vinyl chloride-based polymer. , as an isocyanate-urethane compound, AD-308 manufactured by Toyo Morton Co., Ltd.
A formulation of 80/20 parts by weight of A/CAT-10 (IU-
3), 995.0.
5 (parts by weight) of formulation (B) with a solid content concentration of 20% by weight toluene/methyl ethyl ketone = 1/I (by weight) solution so that the coating amount was 3.5 g/m'' (based on solid content). was coated with a gravure coater at a temperature of 95°C.
Dry for 1 minute.

Next, the sheet was vacuum-formed with the (B) side facing inside to make a container, and the container was filled with miso.

On the other hand, the vinylidene chloride surface of a biaxially stretched polyethylene terephthalate film (15μ) coated with vinylidene chloride was printed, and a 100μ unstretched polyethylene terephthalate film was dry laminated on the printed surface using a urethane adhesive, and a lid was attached. A material is prepared, and the polyester unstretched film surface of the lid material and the (B) surface of the container are sealed by heat sealing at the peripheral edge of the opening of the container.
two. The evaluation results are shown in Table-1.

Example 4 Vacuum formed container in Example 1 P P 335μ/E
Similar evaluations were made using vacuum-formed containers from the sorting of VOH (E-1) 30μ/PP335μ.

Comparative Examples 1 to 4 The lid materials of Comparative Examples 1 to 4 listed in Table 1, which correspond to Example 1 which does not satisfy the constitution of the present invention, were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 5 EV used in Example 1 for biaxially oriented polypropylene 20μ
OH(E-1) 15μ and isocyanate-urethane adhesive (AD-570A/CAT-10) 2.5g
/m' (based on solid content), and then dry laminated the same EVOH surface with the same isonoanate-urethane adhesive to form a 50μ thick film made of 80 parts by weight of polypropylene and 20 parts by weight of low-density polyethylene. I made the lid material by dry laminating.

On the other hand, PP335μ/EVOH(E-1) 30μ/
A container vacuum-formed with a P P 335μ notebook was filled with miso, and the polypropylene-low-density polyethylene composition layer of the lid material was heat-sealed at the periphery of the opening of the container to seal it.

The evaluation results are shown in Table-1.

Comparative Examples 6 to 9 Comparative Examples 6 to 9 listed in Table 1 corresponding to Example 2 were evaluated in the same manner as in Example 2, and the results are shown in Table 1.

Comparative Example 1〇EV used in Example 2 for uniaxially stretched polypropylene 20μ
OH (E-2) was added to the isocyanate-urethane adhesive (EPS-75A/KVi"-4) in the same manner as in Example 2.
Tri-laminate using 0) and dry-laminate a polypropylene (thickness 30μ) film on the EVOH surface using the same urethane-based adhesive L) to make a lid material.

On the other hand, PP235μ/EVOH(E-1) 30tt
/P P A container vacuum-formed with a 235μ notebook was filled with miso, and the polypropylene layer of the lid material was heat-sealed around the opening of the container to seal it.

The evaluation results are shown in Table-1.

According to the present invention, it is possible to obtain a laminate, a lid material, and a container that are excellent in ease of opening, preservation of contents, and transparency, and are inexpensive.

[Brief explanation of drawings]

1 to 3 are examples of enlarged cross-sectional schematic diagrams of the sealed container according to the present invention. 1...Base material (C) layer 2...Printed layer 3...Adhesive layer 4...Composition (A) layer 5...Composition (B) layer 6...Container body patent application People Rila Shi Co., Ltd.

Claims (6)

[Claims] (1) A layer of the composition (A) consisting of an ethylene-vinyl alcohol copolymer and a polyolefin, and a layer of the composition (A) consisting of a vinyl chloride polymer and an isocyanate-urethane compound (
A laminate consisting of the layers of B). (2) A laminate having a C/A/B configuration comprising a base material (C) made of at least one selected from a thermoplastic resin, a metallized thermoplastic resin, and a metal foil, and the laminate according to claim 1. . (3) A lid material comprising the laminate according to claim 2. (4) A container made of at least one selected from thermoplastic resin, metal, and glass, and a lid material according to claim 3, wherein the (B) layer of the lid material and the container are connected to the opening peripheral portion of the container. A hermetically sealed container. (5) A molded container comprising the laminate according to claim 2. (6) A molded container according to claim 5 and a lid material made of at least one selected from thermoplastic resin, metallized thermoplastic resin, and metal foil, and the lid material and the layer (B) of the molded container are A sealed container formed by sealing the periphery of the opening of the molded container.