JPH1158619A - Multilayer laminated sheet of thermoplasting resin and multilayer laminated container using this sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer laminated sheet of a thermoplastic resin which shows superb interlayer adhesive properties, thermal moldability, rigidity and oxygen barrier properties and at the same time, outstanding aroma maintenance for the content of a container and is especially best suited for a container for a refresher, a fruit juice or favorite drink as well as a multilayer laminated container made of the multilayer laminated sheet. SOLUTION: This multilayer laminated sheet of a thermoplastic resin comprises a styrene resin layer C laminated on both faces of an oxygen barrier resin layer A through a modified olefin polymer layer B and a saturated polyester resin layer E laminated on at least one of the faces of the styrene resin layer C through a block copolymer resin layer D made up of a polymer block of a monovinyl-substituted aromatic hydrocarbon and a polymer block of a conjugated diene. The multilayer laminated container is thermally molded using the multilayer laminated sheet and has the saturated polyester resin layer E as an innermost layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin multilayer laminated sheet and a multilayer laminated container comprising the same.
More specifically, it has interlayer adhesiveness, thermoformability, rigidity, and oxygen barrier properties, and also has excellent aroma retention of the contents when made into a container, and is particularly used for soft drinks, fruit juice drinks, and food and drink containers. The present invention relates to a thermoplastic resin multilayer laminated sheet suitable as the above, and a multilayer laminated container comprising the same.

[0002]

2. Description of the Related Art Conventionally, styrene resins having excellent thermoformability and rigidity have been used as containers for soft drinks, fruit juice drinks, favorite foods and drinks, etc. As a middle layer, an ethylene-vinyl alcohol copolymer resin layer is provided through an adhesive layer of a modified olefin resin or the like to provide an oxygen barrier property, and is composed of a multilayer laminated sheet in which deterioration in quality due to oxidation of contents is suppressed. The spread of containers is remarkable. However, when the container made of the multilayer laminated sheet is used as a container for soft drinks, fruit juice drinks, foods and drinks, and the like, there are problems such as impairing the aroma of the contents and reducing the flavor.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art in the above-mentioned multilayer laminated sheet, and has interlayer adhesion, thermoformability, rigidity, and oxygen barrier properties, and It is an object to provide a thermoplastic resin multilayer laminated sheet which is excellent in aroma retention of the contents when the container is used, and is particularly suitable as a container for soft drinks, fruit juice drinks, favorite foods and drinks, and a multilayer laminated container comprising the same. I do.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, further laminating a saturated polyester resin layer on the conventional multilayer laminated sheet;
In addition, the present inventors have found that the above object can be achieved by interposing a specific resin in the lamination, and have reached the present invention. Therefore, the present invention provides a modified olefin-based resin on both surfaces of the oxygen barrier resin layer (A). Polymer layer (B)
A styrene-based resin layer (C) is laminated via at least one surface of the block copolymer resin layer (D) composed of a polymer block of a monovinyl-substituted aromatic hydrocarbon and a polymer block of a conjugated diene. A thermoplastic resin multilayer laminated sheet having a saturated polyester resin layer (E) laminated thereon, and a multilayer laminated container obtained by thermoforming the sheet and having a saturated polyester resin layer (E) as an innermost layer;
Is the gist.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as the oxygen barrier resin constituting the oxygen barrier resin layer (A), specifically, ethylene-vinyl alcohol copolymer resin, polyamide resin and the like are representative. It is mentioned as a thing.

The ethylene-vinyl alcohol copolymer resin is generally obtained by saponifying an ethylene-vinyl acetate copolymer. In the present invention, the ethylene content is 10 to 65 mol%, In particular, it is preferably 20 to 50 mol%, and has a saponification degree of 90% or more, particularly preferably 95% or more.

Further, as the polyamide resin, ε-
Caprolactam, polymers of lactams such as ω-laurolactam, polymers of aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, hexamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4- or 2,
Aliphatic diamines such as 4,4-trimethylhexamethylenediamine, alicyclic diamines such as 1,3- or 1,4-bis (aminomethyl) cyclohexane, bis (p-aminocyclohexylmethane), m- or p- Diamine units such as aromatic diamines such as xylylenediamine; aliphatic dicarboxylic acids such as adipic acid, suberic acid and sebacic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid Polycondensates with dicarboxylic acid units such as acids, and copolymers thereof; specifically, nylon 6, nylon 9, nylon 11, nylon 12, nylon 66,
Nylon 610, nylon 611, nylon 612, nylon 6T, nylon 6I, nylon MXD6, nylon 6/66, nylon 6/610, nylon 6 / 6T,
Nylon 6I / 6T and the like, among which nylon 6 and nylon MXD6 are preferred.

In the present invention, the modified olefin polymer constituting the modified olefin polymer layer (B) may be a modified olefin polymer having 2 carbon atoms such as ethylene, propylene and butene-1.
About 8 to about 8 α-olefin homopolymers,
Olefin and ethylene, propylene, butene-1,3-
Other α-olefins having about 2 to 20 carbon atoms such as methylbutene-1, pentene-1, 4-methylpentene-1, hexene-1, octene-1, decene-1, and the like, vinyl acetate, vinyl chloride, acrylic acid Olefin resins, such as copolymers with vinyl compounds such as methacrylic acid, acrylic acid esters, methacrylic acid esters, and styrene; ethylene-propylene copolymers; ethylene-propylene-diene copolymers; ethylene-butene-1 Copolymers, propylene rubber such as propylene-butene-1 copolymer, acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid,
Maleic acid, fumaric acid, itaconic acid, citraconic acid, unsaturated carboxylic acids such as tetrahydrophthalic acid, or their acid halides, amides, imides, anhydrides, derivatives such as esters, specifically, maleenyl chloride, maleimide, Maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, glycidyl maleate and the like modified under graft reaction conditions are typical examples, among which unsaturated dicarboxylic acid or its anhydride, Particularly, an ethylene resin, a propylene resin, or an ethylene-propylene or butene-1 copolymer rubber modified with maleic acid or its anhydride is preferable.

Here, the modified olefin polymer includes not only the modified product itself modified by the above method, but also a product obtained by diluting the modified product with an unmodified product. The content of the unsaturated carboxylic acid or its derivative unit is from 0.01 to 10% by weight, especially from 0.1 to 10% by weight.
It is preferably from 0.5 to 5% by weight. The modified olefin polymer layer (B) may further include, for example, a styrene-butadiene block copolymer elastomer, a styrene-isoprene block copolymer elastomer, and a hydrogenated product thereof for the purpose of enhancing adhesion. Of the styrene-based elastomer and the modified olefin-based polymer in a total amount of 5
About 60% by weight.

In the present invention, the styrene resin constituting the styrene resin layer (C) includes styrene,
homo- or copolymers of styrene-based monomers such as α-methylstyrene, p-methylstyrene, dimethylstyrene, pt-butylstyrene, chlorostyrene, etc., and copolymers of these styrene-based monomers with other monomers, for example, styrene -Acrylonitrile copolymer (AS resin), their styrenic monomers or further other monomers,
Graft polymer obtained by graft polymerization in the presence of a diene rubber polymer such as polybutadiene, styrene-butadiene copolymer, polyisoprene, polychloroprene, etc., for example, high impact polystyrene (HIPS resin), styrene-acrylonitrile graft polymer (ABS) And polystyrene (GPPS resin) and high-impact polystyrene (HIPS resin).

In the present invention, the block copolymer resin constituting the block copolymer resin layer (D) comprising a polymer block of a monovinyl-substituted aromatic hydrocarbon and a polymer block of a conjugated diene is a linear copolymer. Various, such as shape, radial branch shape, branch taper shape are known,
In the present invention, a linear or radially branched one is preferred. Here, the linear block copolymer is represented by the general formula (XY) _n , X- (YX) _n , Y- (XY).
_n [where X is a polymer block of a monovinyl-substituted aromatic hydrocarbon, Y is a polymer block of a conjugated diene, and n
Is an integer of 1 or more, generally 1 to 5. Etc., and the radiation-branched block copolymer is represented by the general formula (XY) _n -Z, X _n- (YX) _m-
Z, Y _n- (XY) _m -Z wherein X and Y are the same as above, and Z is a residue of the polyfunctional coupling agent used for forming the radially branched block. ,
n and m are 1 or more, generally an integer of 1 to 5. ] Etc. are represented.

In the block copolymer, examples of the monovinyl-substituted aromatic hydrocarbon constituting the polymer block X include styrene, α-methylstyrene, p-methylstyrene, dimethylstyrene, vinylnaphthalene and the like. Examples of the conjugated diene constituting the polymer block Y include butadiene and isoprene. Examples of the polyfunctional coupling agent include those having three or more functions such as polyepoxides, polyisocyanates, polyaldehydes, polyketones, and polyamines. In the present invention, among the above block copolymer resins, a styrene-butadiene block copolymer is preferred, and those having a styrene content of 60 to 90% by weight and a butadiene content of 40 to 10% by weight are particularly preferable. preferable.

In the present invention, the saturated polyester resin constituting the saturated polyester resin layer (E) includes ethylene glycol, propylene glycol,
Aliphatic diols such as 4-butanediol, neopentyl glycol, hexamethylene glycol, diethylene glycol, 1,1-cyclohexane dimethylol, 1,
Alicyclic diols such as 4-cyclohexane dimethylol,
Diol units such as aromatic diols such as bisphenol and 2,2-bis (4′-hydroxyphenyl) propane; aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid and undecadicarboxylic acid; Hydroterephthalic acid, an alicyclic dicarboxylic acid such as hexahydroisophthalic acid, terephthalic acid, isophthalic acid, a polycondensate with a dicarboxylic acid unit such as an aromatic dicarboxylic acid such as naphthalene dicarboxylic acid, as long as it shows thermoplasticity ,
It may be modified with a small amount of triol or tricarboxylic acid, and specifically, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene terephthalate / isophthalate copolymer, etc., among which polyethylene terephthalate, A polyethylene terephthalate-based resin such as a polyethylene terephthalate / isophthalate copolymer is preferred.

The thermoplastic resin multilayer laminate sheet of the present invention composed of the above-mentioned resins and the like has a styrene-based resin layer (A) on both sides of an oxygen-barrier resin layer (A) via a modified olefin-based polymer layer (B). C) are laminated, and on at least one surface thereof, a saturated polyester resin layer (E) is interposed via a block copolymer resin layer (D) comprising a polymer block of a monovinyl-substituted aromatic hydrocarbon and a polymer block of a conjugated diene. ) Are stacked. Here, when the saturated polyester resin layer (E) is not provided, the scent retention of the contents when the container is formed cannot be imparted, and when the block copolymer resin layer (D) is not provided, the container When the cover material (for example, a multilayer laminated film of polyethylene terephthalate / aluminum / polyethylene) is peeled off, there arises a problem that the saturated polyester resin layer (E) on the container side peels off. When the oxygen-barrier resin layer (A) is not provided, the oxygen-barrier property is naturally insufficient, and when the styrene-based resin layer (C) is not provided, the thermoformability is inferior.

The layer structure of the thermoplastic resin multi-layer laminated sheet of the present invention has a basic structure of E / D / C / B / A /
In addition to B / C, pulverized scraps generated in the manufacturing process of the multilayer laminated sheet and the manufacturing process of the multilayer laminated container described later were further laminated as a scrap layer (F).
C / F / B / A / B / C, E / D / C / B / A / B / F
/ C, E / D / C / F / B / A / B / F / C, etc. Further, a layer made of another resin may be provided between each layer for the purpose of imparting a new function. it can. The pulverized scrap may be used as a single layer of the multilayer laminated sheet as described above, or may be mixed with the styrene resin layer (C).

The production of the multilayer laminated thermoplastic resin sheet of the present invention is carried out by conventionally known sequential extrusion lamination, sandwich extrusion lamination, co-extrusion molding, a combination thereof, and the like. It is advantageous. In the co-extrusion molding, usually, the resin constituting each layer is melt-kneaded by each extruder, integrated and laminated using a feed block or the like, coextruded into a sheet shape from a T-die, and then cooled by a molding roll or the like. And solidify to form a multilayer laminated sheet. The temperature of the feed block and the T-die at the time of molding should be equal to or higher than the melting point of each resin in order to uniformly melt the resin constituting each layer, and equal to or lower than 80 ° C. higher than the melting point of each resin in order to suppress thermal deterioration. Is preferred.

The thickness of the thermoplastic resin multilayer sheet of the present invention is 0.1 to 5.0 mm, the thickness of each layer is 10 to 1500 μm for the oxygen barrier resin layer (A), and the modified olefin polymer layer. (B) is 10 to 500 μm each (note that
Each B layer does not need to be the same thickness. ), The styrene-based resin layer (C) including the scrap layer (F) is 25 to
4950 μm (each C layer and each F layer when a plurality of F layers are provided need not have the same thickness), and the block copolymer resin layer (D) is 10 to 5 μm.
00 μm, saturated polyester resin layer (E) is 10 to 50
It is preferably about 0 μm.

The multilayer laminated container of the present invention is obtained by thermoforming the above-described thermoplastic resin multilayer laminated sheet, and has a saturated polyester resin layer (E) as the innermost layer. Here, examples of the thermoforming method include a conventionally known vacuum forming method, a pressurized air forming method, a vacuum pressurized air forming method, and a plug assisted forming method, and the like. The surface temperature is at least 50 ° C. lower than the melting point of the resin constituting each layer, and is 5 ° below the melting point.
It is preferable that the temperature be 0 ° C. or higher.

[0019]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention. In the following examples and comparative examples, various physical properties and performance evaluation methods of the thermoplastic resin multilayer laminated sheet and the multilayer laminated container are based on the following methods.

(1) Oxygen barrier resin layer (A) and styrene
According to JIS K6854, the A layer and the C layer at one end were peeled in advance using a 10 mm wide strip sample collected from the adhesive strength multilayer laminated sheet between the base resin layer (C) or the scrap layer (F). At a peeling speed of 50 mm / min.
A shape peel test was performed.

(2) Styrene resin layer (C) and saturated polyether
According to JIS K 6854, the C layer at one end and the E layer were peeled in advance using a 10 mm wide strip sample taken from the adhesive strength multilayer laminated sheet between the stell resin layers (E) , and the peeling speed was 50 mm / min. At 1
An 80 degree peel test was performed.

(3) Using an oxygen-permeable multilayer laminated sheet, "O" manufactured by Modern Control Co., Ltd.
X-TRAN 10-50A "at 20 ° C, 65% RH
The oxygen permeation amount was measured under the following conditions.

(4) Thermoformable 30 cm × 30 cm sheet taken from the multilayer laminated sheet is subjected to a far-infrared ceramic heater from both sides to a surface temperature of 1 cm.
After preheating to 30 to 220 ° C., the saturated polyester resin layer (E) becomes the inner layer of the container, and has a diameter of 5.5 cm.
A cylindrical container having a depth of 11 cm was subjected to plug-assist vacuum pressure forming, and a case where the designed container was formed was evaluated as ○, and the others were evaluated as ×.

(5) Aroma Retention of Contents The container obtained in the evaluation of thermoformability is filled with about 200 cc of 100% fruit juice orange juice, and covered with a lid material composed of a multilayer laminated film of polyethylene terephthalate / aluminum / polyethylene. After the polyethylene side was sealed as a sealing surface and stored at 5 ° C. for one week, a panel selected arbitrarily evaluated the aroma, color, and taste in comparison with the same orange juice stored separately. If 7 or more of the 10 panelists determined that there was no change, ○; otherwise, ×
Was evaluated.

(6) Removability of lid material The container obtained in the evaluation of the thermoformability was sealed with a lid material comprising a multilayer laminated film of polyethylene terephthalate / aluminum / polyethylene with the polyethylene side as a sealing surface, and then optionally sealed. The selected panelists peeled off the lid material, and when 7 or more of the 10 panelists could easily peel off the sealing surface, the evaluation was evaluated as ○, and the others were evaluated as ×.

Example 1 Ethylene-vinyl alcohol copolymer resin (ethylene content: 44 mol%, "Eval EF-E151B" manufactured by Kuraray Co., Ltd.) as a resin for layer A, and maleic anhydride-modified polyethylene resin as resin for layer B ( Maleic anhydride unit content 0.1 wt%, melt flow rate 1.0 g / 10 min,
"F3300F" manufactured by Mitsubishi Chemical Corporation), high impact polystyrene resin ("47" manufactured by Asahi Kasei
5D "), a styrene-butadiene block copolymer resin (styrene content 75% by weight, melt flow rate 8.0 g / 10 min," K-RESIN KR-05 "manufactured by Philippe Spectro Chemical Co., Ltd.) as a resin for the D layer, Using a copolymerized polyethylene terephthalate resin (“PET-G 6763” manufactured by Eastman Chemical Co., Ltd.) as a resin for the E layer, each was melt-kneaded with five single-screw extruders, and 230 ° C.
Integrated with the feed block set to
After co-extrusion in a sheet form from a T-die set at 230 ° C., the mixture is cooled and solidified by a forming roll composed of three polishing rolls to obtain a copolymerized polyethylene terephthalate resin layer (E) 100 μm / styrene-butadiene block copolymer. Polymer resin layer (D) 100 μm / high impact polystyrene resin layer (C) 600 μm / maleic anhydride-modified polyethylene resin layer (B) 50 μm / ethylene-vinyl alcohol copolymer resin layer (A) 50 μm
m / Maleic anhydride-modified polyethylene resin layer (B) 50
μm / High impact polystyrene resin layer (C) 600
Thus, a thermoplastic resin multilayer laminated sheet having a total thickness of 1550 μm having a layer configuration of five types and seven layers of μm was produced.

With respect to the obtained multilayer laminated sheet, the adhesive strength between the ethylene-vinyl alcohol copolymer resin layer (A) and the high impact polystyrene resin layer (C), and the high impact polystyrene resin layer (C) and the copolymerized polyethylene terephthalate Adhesive strength between the resin layers (E), and
The oxygen permeability was measured. Separately, a multilayer laminated container was manufactured from the obtained multilayer laminated sheet by the thermoforming method described in the above evaluation method, and the thermoformability at that time was evaluated. Furthermore, about the obtained multilayer laminated container, the fragrance retention of the content and the peelability of the lid material were evaluated. The results are shown in Table 1.

Example 2 Scraps of the multilayer laminated sheet produced during the production of Example 1 were further laminated, and a copolymerized polyethylene terephthalate resin layer (E) 100 μm / styrene-butadiene block copolymer resin layer (D ) 100 μm / high impact polystyrene resin layer (C) 200 μm / scrap layer (F) 400 μm / maleic anhydride modified polyethylene resin layer (B) 50 μm / ethylene-vinyl alcohol copolymer resin layer (A) 50 μm / maleic anhydride modified Polyethylene resin layer (B) 50 μm / scrap layer (F) 4
00 μm / high impact polystyrene resin layer (C) 2
A multilayer laminated sheet and a multilayer laminated container were manufactured in the same manner as in Example 1 except that the layer structure was composed of 9 types of 6 layers of 00 μm, and various physical properties and performances were similarly evaluated. The results are shown in Table 1. .

Comparative Example 1 A multilayer laminated sheet and a multilayer laminated container were produced in the same manner as in Example 1 except that the styrene-butadiene block copolymer resin layer (D) was not provided. Various physical properties and performances were evaluated, and the results are shown in Table 1.

Comparative Example 2 The procedure of Example 1 was repeated except that the copolymerized polyethylene terephthalate resin layer (E) and the styrene-butadiene block copolymer resin layer (D) were not provided. A laminated sheet and a multilayer laminated container were manufactured, and various physical properties and performances were similarly evaluated. The results are shown in Table 1.

Comparative Example 3 A container was produced in the same manner as in Example 1 except that a single-layer sheet was produced from the same copolymerized polyethylene terephthalate resin used in Example 1, and various physical properties and performances were evaluated in the same manner. The results are shown in Table 1.

[0032]

[Table 1]

[0033]

According to the present invention, in addition to having interlayer adhesiveness, thermoformability, rigidity, and oxygen barrier properties, it is also excellent in aroma retention of contents when used as a container, and is particularly suitable for soft drinks and fruit juice drinks Thus, it is possible to provide a thermoplastic resin multilayer laminated sheet suitable as a container for favorite foods and drinks, and a multilayer laminated container comprising the same.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B32B 27/30 B32B 27/30 B 27/32 27/32 C 27/36 27/36 B65D 65/40 B65D 65/40 D ( 72) Inventor Katsuhito Takahashi 2031-2 Akado, Ogasa-machi, Ogasa-gun, Shizuoka Prefecture Inside the Tokai Plant of Ikoma Chemical Industry Co., Ltd.

Claims (4)

[Claims] 1. A styrene resin layer (C) is laminated on both sides of an oxygen barrier resin layer (A) via a modified olefin polymer layer (B), and at least one surface of the styrene resin layer (C) is a monovinyl-substituted aromatic compound. A thermoplastic resin multilayer sheet comprising a saturated polyester resin layer (E) laminated via a block copolymer resin layer (D) comprising a hydrocarbon polymer block and a conjugated diene polymer block. . 2. The thermoplastic resin multilayer sheet according to claim 1, wherein the oxygen-barrier resin layer (A) comprises an ethylene-vinyl alcohol copolymer resin. 3. The thermoplastic resin multilayer sheet according to claim 1, wherein the block copolymer resin layer (D) comprises a styrene-butadiene block copolymer resin having a styrene content of 60 to 90% by weight. 4. A multilayer laminated container obtained by thermoforming the thermoplastic resin multilayer laminated sheet according to any one of claims 1 to 3, and having a saturated polyester resin layer (E) as an innermost layer.