JP2002096847A - Squeezing vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a squeezing vessel which is non-adsorptive to active principles and perfume of contents such as medicines and food. SOLUTION: This squeezing vessel is formed by blow-molding multi-layered parison with a bottom opening end heat-sealed, and the multi-layered parison is a laminate comprising an olefin resin outer layer, an inner layer of substantially amorphous copolymer polyester which consists of diol other than cyclohexane methanol and dicarboxyl acid other than isophthalic acid while diol consisting of ethylene glycol and diol other than ethylene glycol and mole percentage of ethylene glycol to diol other than ethylene glycol is 50:50 to 95:5, and an adhesive resin intermediate layer, and the bottom-sealed part is substantially amorphous with inner layers bonded to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squeezed container, and more particularly to a squeezed container in which evaporation of a solvent from a bottom heat seal portion and off-flavor are prevented.

[0002]

2. Description of the Related Art Conventionally, squeezed containers such as extrusion tubes for accommodating highly viscous liquid articles such as toothpastes, cosmetics, various chemicals and foods, and viscous materials such as ketchup, mayonnaise, jam and chocolate. BACKGROUND ART As squeeze bottles (squeeze bottles) for storing foods and the like, those made of various flexible laminates are known.

Various types of plastic flexible laminates for squeezed containers are known. In a squeeze container formed by blow molding a multi-layer parison and heat sealing at the bottom opening end, for example, a laminate in which the inner layer is made of polyolefin is mainly used. This is because the polyolefin is fused at a low temperature and has high strength. However, polyolefins have the property of easily adsorbing fragrance components, and have the drawback of adsorbing fragrances contained in contents such as toothpastes and cosmetics, leading to a reduction in flavor level.

[0004] Therefore, for applications such as food, ethylene-
A laminate in which an oxygen barrier layer made of a vinyl alcohol copolymer, nylon or the like is used as an intermediate layer, and an olefin resin layer such as polyethylene is laminated on both sides of the intermediate layer is generally used. For chemicals containing solvents, etc.
A laminate having an inner layer of saponified ethylene-vinyl acetate copolymer, nylon or the like and an outer layer of an olefin resin has been used.

At the time of molding a container, these flexible laminates are overlapped and joined to form a cylinder, and one end of the cylindrical body is provided with a screw-out port formed by injection molding of a resin. And the conical shoulder connected thereto are adhered, and the other end of the cylindrical body is closed by fusion or the like. further,
The multilayer parison made of the above-mentioned laminate is blow-molded in a split mold to form a squeezed container. In addition,
No. 57338 discloses that a multi-layer parison is blow-molded in a split mold to form a bottle, the bottom of the bottle is cut off, the contents are filled from the cut open end, and the open end edges are heat-sealed to each other. Lap joining and sealing are described.

A squeezed container in which the inner layer is formed of a chemical-resistant resin such as ethylene-vinyl alcohol copolymer or nylon and the bottom opening edges are sealed by heat sealing is such that the inner layer resin is not attacked by an organic solvent or the like. Despite the advantages, these chemical resistant resins have poor heat sealing properties or have the disadvantage that heat sealing must be performed at elevated temperatures.

That is, at the bottom heat seal portion of the container,
The inner layer ethylene-vinyl alcohol copolymer or chemical-resistant resin such as nylon causes thermal deterioration and oxidative deterioration, generates cracks, etc., and solvent components permeate from this part,
It is recognized that the solidification of the contents may cause a trouble that it is difficult to remove the contents.

In order to prevent this drawback, Japanese Patent Publication No. Hei 3-6
No. 4389 discloses an olefin resin outer layer, a first intermediate layer made of an ethylene-vinyl alcohol copolymer, a second intermediate layer made of an olefin resin or a relatively thick adhesive resin, and an ethylene-vinyl alcohol copolymer. It is described that a chemical resistant squeezed container is formed from a multilayer parison composed of a laminate in which body layers are laminated in this order. However, the layer structure is complicated, and the poor heat sealing property of the chemical resistant resin has not been solved.

[0009]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a squeezed container which eliminates the above-mentioned disadvantages. An object of the present invention is to provide a squeeze container having non-adsorbing properties, especially for active ingredients and fragrances of contents such as medicines and foods.

Another object of the present invention is to provide a squeezed container of this kind in which the inner layer has a combination of excellent chemical resistance and heat sealability, so that the solvent is prevented from evaporating from the bottom heat seal portion. It is another object of the present invention to provide a squeezed container that prevents solidification of the contents in this portion and can maintain the state of the solvent-containing contents substantially the same as that at the time of filling.

[0011]

According to the present invention, there is provided a squeezed container formed by blow molding a multi-layer parison and heat sealing at the bottom open end, wherein the multi-layer parison comprises:
An olefin-based resin outer layer, a copolymerized polyester comprising a diol other than cyclohexanedimethanol and a dicarboxylic acid other than isophthalic acid, wherein the diol comprises ethylene glycol and a diol other than ethylene glycol, and ethylene glycol and ethylene glycol. And a glue resin interlayer having a molar ratio to the other diol in the range of 50:50 to 95: 5, and an adhesive resin intermediate layer. The present invention relates to a squeezed container characterized by being fused and substantially amorphous.

In the present invention, the diol constituting the copolyester forming the inner layer of the multilayer parison comprises ethylene glycol and a diol other than ethylene glycol, and the molar ratio of ethylene glycol to the diol other than ethylene glycol is 50: It is preferable that the ratio be in the range of 50 to 95: 5 from the viewpoints of chemical resistance, heat sealability, sealing reliability of the heat seal portion, and non-adsorption to contents.

[0013] The present invention provides a copolymerized polyester comprising a diol other than cyclohexanedimethanol and a dicarboxylic acid other than isophthalic acid as the inner layer of a multilayer parison for forming a squeezed container, wherein the diol is ethylene glycol and ethylene glycol. And a substantially amorphous copolymer polyester having a molar ratio of ethylene glycol to a diol other than ethylene glycol in the range of 50:50 to 95: 5.

Among various thermoplastic resins, polyester is excellent in chemical resistance. This chemical resistance is believed to be due to strong hydrogen bonds between polyester molecular chains. On the other hand, since polyester has a higher melting point than olefin-based resins and the like, at the time of heat sealing, the sealing portion tends to crystallize and become mechanically brittle, or tend to form pinholes due to volume shrinkage. . As a means for lowering the melting point of the polyester and for lowering the crystallinity, a copolymerization means is generally used. However, most copolyesters have reduced chemical resistance as well as reduced melting points and crystallinity.

According to the present invention, there is provided a copolymerized polyester comprising a diol other than cyclohexanedimethanol and a dicarboxylic acid other than isophthalic acid, wherein the diol comprises ethylene glycol and a diol other than ethylene glycol. By forming a substantially amorphous copolymerized polyester having a molar ratio with a diol other than glycol in the range of 50:50 to 95: 5 as the inner layer of the multilayer parison for forming a squeezed container,
The advantage is that the inner layer has a relatively low melting point and excellent heat sealability, and the seal does not crystallize even during the cooling process from the heat seal temperature to room temperature, and has excellent chemical resistance. obtain.

The substantially amorphous copolymerized polyester using a combination of ethylene glycol and a diol other than ethylene glycol as the diol has a maximum achievable crystallinity level significantly lower than that of polyethylene terephthalate or the like. For example, while the maximum crystallinity reached by the density method is generally suppressed to 10% or less, the solvent resistance and the barrier property against solvent vapor are remarkably excellent. Compared to a polyester using ethylene glycol alone as a diol, a copolymerized polyester using ethylene glycol and a diol other than ethylene glycol has a reduced tendency to crystallize and has an excellent barrier property against solvent vapor. Show.

A bottom sealed type squeezed container filled with contents containing an organic solvent is under severe conditions that cannot be compared with ordinary containers. That is, many of the organic solvents promote crystallization of the heat-sealable polyester and promote environmental cracking. If distortion, pinholes or cracks occur at the bottom seal due to crystallization,
The highly permeable organic solvent volatilizes from this part, causing the contents to deteriorate. In the present invention, the copolymerized polyester forming the heat-sealed portion is maintained in a substantially amorphous state even under the condition of being exposed to the organic solvent vapor, and has excellent solvent resistance and excellent barrier properties against the solvent vapor. Because
The permeation and evaporation of the solvent from the bottom heat seal portion can be prevented, and the solidification of the contents in this portion can be prevented.

In the squeezing container of the present invention, it is sufficient that the copolyester is present in a thin layer on the inner surface of the multilayer laminate, and the outer layer of the olefin resin provided on the inner layer via the adhesive resin intermediate layer is sufficient. , While protecting the inner layers,
It imparts moisture resistance to the container and also gives plastic deformation necessary for squeezing the contents.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION <Squeezed Container> The squeezed container of the present invention is formed by blow molding a multi-layer parison and heat sealing the lower opening end. 1, 2 and 3 showing a specific example of the squeezed container (tube container) of the present invention, the tube container comprises a tube main body 1 and a lid 2.
The tube body 1 comprises a threaded extrusion opening 3 integrally formed by blow molding of a multi-layer parison, a flexible conical shoulder portion 4 connected thereto, and a trunk wall 5 forming a cylindrical trunk portion. Having.

FIG. 3 is an enlarged view of a cross section of the wall of the multilayer parison.
The body wall 5 comprises an inner layer 6 made of a copolyester, an olefin resin outer layer 7, and an adhesive resin intermediate layer 8 interposed between these layers.

In FIG. 2, a body wall 5 forming a cylindrical body is provided.
Has a cut edge 9 at which the bottom heat-seal portion 10 is formed by overlapping and fusing the inner layer 6 facing the body wall.

<Inner Layer> In the squeezing container of the present invention, the inner layer is made of a copolyester composed of a diol other than cyclohexanedimethanol and a dicarboxylic acid other than isophthalic acid. The diol other than cyclohexanedimethanol comprises a combination of ethylene glycol and a diol other than ethylene glycol. The molar ratio between ethylene glycol and a diol other than ethylene glycol is in the range of 50:50 to 95: 5. As diols other than ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexylene glycol, bisphenol A
And diethylene glycol.

Examples of dicarboxylic acids other than isophthalic acid include terephthalic acid, p-β-oxyethoxybenzoic acid,
Examples thereof include naphthalene 2,6-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, 5-sodium sulfoisophthalic acid, adipic acid, sebacic acid, and alkyl ester derivatives thereof. The dicarboxylic acid other than isophthalic acid is preferably composed of terephthalic acid alone or a combination of terephthalic acid and a dicarboxylic acid other than terephthalic acid.

The copolymerized polyester constituting the inner layer has at least a molecular weight capable of forming a film. The copolyester constituting the inner layer is generally prepared by using a capillary viscometer in a mixed solvent of phenol and tetrachloroethane in a weight ratio of 60:40 at a temperature of 3%.
The intrinsic viscosity (η) measured at 0 ° C. is 0.3 to 2.8 dl /
g, particularly preferably 0.4 to 1.8 dl / g. For injection molding, it is preferable to use a copolymer polyester having a relatively low molecular weight. For extrusion molding, it is preferable to use a copolyester having a relatively high molecular weight.

<Outer Layer> In the squeezed container of the present invention, the outer layer is made of an olefin resin. As the olefin resin, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, isotactic polypropylene, crystalline propylene-ethylene copolymer, crystalline ethylene-butene-1 copolymer, Examples thereof include a crystalline propylene-butene-1 copolymer, an ethylene-vinyl acetate copolymer, an ion-crosslinked olefin copolymer (ionomer), and a blend of two or more of these.

<Intermediate Layer of Adhesive Resin> In the squeezing container of the present invention, the intermediate layer interposed between the outer layer of the olefin resin and the inner layer of the copolymerized polyester is made of an adhesive resin. As the adhesive resin, any thermoplastic resin exhibiting adhesiveness to the outer layer and the inner layer can be used. Suitable adhesive resins include, for example, olefinic resins graft-modified with ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid or anhydrides thereof, such as modified polyethylene. it can.

<Layer Structure> The squeezed container of the present invention has a container wall thickness of 1.0 to 0.1 mm, especially 0.5 to 0.2 mm.
mm. Thickness of outer layer of olefin resin (Ta) and thickness of inner layer of copolymerized polyester (T
b) means Ta: Tb = 2: 1 to 20: 1, especially 5: 1
It is preferred that the thickness ratio be up to 15: 1. Ta and the thickness (Tc) of the adhesive resin intermediate layer are Ta: Tc = 5: 1 to 1
The thickness ratio is preferably 40: 1, particularly preferably from 10: 1 to 30: 1. A scrap (burr) resin composition by-produced during the production of the tubular container may be interposed between the outer layer of the olefin-based resin and the intermediate layer of the adhesive resin.

<Manufacturing method> The squeezing container of the present invention can be prepared by, for example, melt-kneading the resin constituting each layer in a number of extruders corresponding to the type of the resin, and forming the resin in the multilayer dies. After being merged so as to become, a co-extrusion through a die orifice, a multi-layer parison, then blow molding in a split mold, bottom cutting, content filling and heat sealing of the open end,
Can be manufactured.

The squeezing container of the present invention is preferably formed entirely of a co-extruded laminate, but only the body is formed of a co-extruded laminate, and the shoulder and the squeezing port (extruding port) are other. Of resin.

[0030]

EXAMPLE 1 The outer layer was made of low-density polyethylene having a thickness of 350 μm (GS650 manufactured by Nippon Unicar Co., Ltd.), and the inner layer was formed of a 30 μm thick.
m copolymerized polyester (SI17 manufactured by Toyobo Co., Ltd.)
3: A multi-layer parison having terephthalic acid and a copolymerized polyester composed of ethylene glycol and a diol composed of a dial other than ethylene glycol) and a modified polyethylene (ER510E manufactured by JPO Corporation) as an intermediate layer was extruded to an outer diameter of 38 mm. And a bottomed thin bottle of 80 mm below the shoulder was blow molded.

For extruding the outer layer, the cylinder diameter is 40 m.
m and an L / D ratio of the screw of 24 are used at a cylinder temperature of 130 ° C. in the first stage, 140 ° C. in the second stage, 150 ° C. in the third stage and 160 ° C. in the fourth stage. An extruder having a cylinder diameter of 20 mm and an L / D ratio of a screw of 20 was set to 180 ° C. in the first stage and 220 ° in the second stage.
The extruder having a cylinder diameter of 20 mm and a screw L / D ratio of 20 was used at a cylinder temperature of 155 ° C. in the first stage and 175 ° C. in the second stage for extruding the intermediate layer. The temperature of the three-layer, three-layer parison die for co-extrusion of each layer was 230 ° C.

Cutting the bottom of the obtained bottomed thin bottle,
The inner surfaces of the opening edge portions were overlapped and heat-sealed to obtain a tube container. The sealing conditions were a heater temperature of 300 ° C., a heating time of 8 seconds, and a pressure bonding time of 9 seconds.

When the heat seal strength was examined, the T peel strength was 16.6 N / 15 mm, and the puncture strength was 374.
N. The puncture strength indicates a puncture load when a tube container is filled with water, sealed, the container is placed horizontally, and a 50 mm square pressing jig is pressed against the body at a speed of 200 mm / min.

Example 2 Example 2 was the same as Example 1 except that the thickness of the inner layer was 60 μm or less. The T-peel strength was 28.1 N / 15 mm and the puncture strength was 637 N.

COMPARATIVE EXAMPLE 1 A PET film having a thickness of 50 μm was heated to a heater temperature of 140.
The T-peel strength was 25.0 N / 15 mm when heat sealed at a temperature of 2 ° C. for 2 seconds.

Reference Example 1 In Examples 1 and 2, (1) low-density polyethylene (GS650 manufactured by Nippon Unicar Co., Ltd.) used for the outer layer and (2) copolymerized polyester (Toyobo Co., Ltd.) used for the inner layer
SI173: a copolymerized polyester composed of terephthalic acid and a diol comprising ethylene glycol and a dial other than ethylene glycol) and (3)
When the amount of adsorbed d-limonene on a polyester (KodarPET-G6763 manufactured by Eastman Chemical Company) composed of 1,4-cyclohexanedimethanol and terephthalic acid was examined, after 15 days, (1) low-density polyethylene was obtained. (2) When the amount of adsorption to the copolymerized polyester is 100%, the relative amount of adsorption to the copolymerized polyester is 18%.
%, And (3) the relative adsorption amount to polyester (PET-G) was 60%.

[0037]

According to the squeezing container of the present invention, since the copolyester forming the inner layer has low crystallinity, low-temperature molding, low-temperature sealing properties, mechanical properties at the time of sealing, pinholes, and the like are satisfied. It is better than some conventional squeezed containers.

In the squeezing container of the present invention, the inner layer is made of a copolymerized polyester having a non-adsorbing property with respect to active ingredients and fragrances of contents such as pharmaceuticals and foods, so that toothpastes and cosmetics having fragrances as contents are included. It is useful as a container for filling.

[Brief description of the drawings]

FIG. 1 is a side view showing an external appearance of an example of a squeezed container of the present invention.

FIG. 2 is a cross-sectional view of the container of FIG.

FIG. 3 is an enlarged sectional view of a multilayer parison wall used for manufacturing the container of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tube main body 2 Lid 3 Screw outlet 4 Shoulder 5 Body wall 6 Copolyester inner layer 7 Polyolefin resin outer layer 8 Adhesive resin intermediate layer 9 Edge 10 Bottom heat seal

Claims (2)

[Claims] 1. A squeezed container formed by blow molding a multi-layer parison and heat-sealing a bottom opening end, wherein the multi-layer parison includes an olefin resin outer layer,
A copolymerized polyester comprising a diol other than cyclohexane dimethanol and a dicarboxylic acid other than isophthalic acid, wherein the diol is composed of ethylene glycol and a diol other than ethylene glycol, and is a mole of ethylene glycol and a diol other than ethylene glycol. It consists of a laminate of an inner layer of a substantially amorphous copolymerized polyester having a ratio in the range of 50:50 to 95: 5 and an intermediate layer of an adhesive resin, and the bottom heat seal portion is formed by fusing the inner layers together. A squeezed container characterized by being substantially amorphous. 2. A diol other than ethylene glycol,
The squeezed container according to claim 1, wherein the squeezed container is at least one diol selected from the group consisting of propylene glycol, neopentyl glycol and diethylene glycol.