JPS6111786B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an extruded tube container with excellent transparency. Extruded tube containers have traditionally been used for toothpaste, cosmetics, etc., but most of them are laminate tubes or polyethylene tubes using aluminum tubes, sheets of aluminum foil laminated with resin films on both sides. All of them are colored and opaque, and you cannot tell what kind of contents are inside unless you remove the cap and push it out.
In addition, deterioration and discoloration due to long-term storage are difficult to discern, which not only suppresses purchasing sentiment but also makes it unhygienic. When manufacturing transparent extruded plastic tubes with excellent preservability and aroma retention for the contents, at least one layer is made of resin with excellent aroma retention and gas barrier properties, and the innermost layer is heat-sealable. In the case of toothpaste, extruded tubes with a multi-layer structure made of hydrophobic resin such as polyethylene have poor wetting and adhesion between the innermost layer resin and the contents, resulting in cracks in the contents in places, which is extremely undesirable in terms of appearance. It was something I didn't have. In addition, hydrophilic resins alone do not have sufficient holding power, hardness, and flexibility as a layer like hydrophobic resins, so they may crack when bent or crushed as a tube container. It was hot. The present invention solves the above-mentioned conventional drawbacks, and in particular, the innermost layer of the tube container is provided with a thermoplastic resin layer that is highly compatible with contents such as toothpaste and cosmetics and has good wettability. This constitutes a tube container having a transparent laminated structure with gas barrier properties. The problem of fragrance retention can be fully guaranteed if gas barrier properties are good. First, the innermost layer, which is used in the extruded tube container with excellent transparency of the present invention and has good gas barrier properties and has good affinity with the contents, that is, has good wettability, contains 5 to 50% hydrophilic thermoplastic synthetic resin and oxidized wax. It is a homogeneous layer made by mixing and melting 95 to 50% of a hydrophobic thermoplastic resin with a small amount of tackifier such as Logi.
At least one of the intermediate or outermost layers is a transparent tube container having a synthetic resin layer with good gas barrier properties. Hydrophilic resins used in the innermost layer include cellulose resins, starch hydrocarbons, polyvinyl alcohol resins, maleic anhydride resins, hydrophilic acrylic resins, polyolefin oxide resins, urea resins, melamine resins, and phenols. Examples include polyamide resins, polyamino resins, polyimino resins, polyvinyl acetate resins, butadiene acrylonitrile copolymers, hydrogenated cyclopentadiene resins, and nylon-based polyamide resins. Hydrophobic synthetic resins used in the innermost layer include polyethylene resins, ionomer resins, and ethylene-vinyl acetate copolymers. In addition, the adhesive agent as a component for the innermost layer is used to prevent the contents from cracking and to improve the adhesion between the contents and the inner surface of the tube.
Examples include rosin, modified rosin, rosin derivatives, polyterpene resins, modified terpenes, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, and cyclopentadiene resins. Also, oxidized wax is used as a mixture for the innermost layer. This is an oxidized wax in which a polar group, such as a carboxyl group, an ester group, or a hydroxyl group, is introduced into the wax molecule through an oxidation reaction.
Base waxes with a molecular weight of 600 to 3,000 and an oxidation value of 5 to 50 include animal, vegetable, mineral waxes, petroleum-based waxes, and synthetic waxes. Oxidized wax has the function of binding inorganic substances and organic substances, and since it is easily oxidized, it has the function of making it easy to get wet with water and the contents. Polyethylene includes low-density, medium-density, and high-density polyethylene, copolymers of propylene and ethylene,
It refers to a modified polyethylene graft-polymerized with an unsaturated carboxylic acid, and low-density polyethylene is convenient. The ionomer resin is a resin made by neutralizing a copolymer of ethylene and an unsaturated carboxylic acid with a metal or a metal salt, and is available as Surlyn (trade name) from DuPont. The ethylene-vinyl acetate copolymer has an ethylene content of 5 to 40 ^W %, preferably 8 to 28 ^W %, and an example of a commercially available product is Elvax. The polyethylene, ionomer resin, and ethylene-vinyl acetate copolymer used for the innermost layer of the tube of the present invention may be mixed in various proportions depending on the purpose of use and contents, as long as the properties of the layer are not essentially impaired. Can be used in The resin used for other layers is polyamide, which has an acid amide group (-CONH-) in the molecule.
There are two types of polyamides: what is usually called nylon, which is obtained by ring-opening polymerization of lactams, self-condensation of aminocarboxylic acids, and condensation of diamines with organic dibasic acids, and dimer acid type polyamides. . The ethylene-vinyl alcohol copolymer has an ethylene content of 5 to 85 mol%, preferably 25 to 75 mol%.
Those containing 2 to 40 mol% of ethylene and a degree of saponification of 90% or more are particularly good in gas barrier properties, fragrance retention, and moisture resistance. Next, an example will be described. Example 1 Polyethylene (specific gravity 0.92MI=
1.3g/10min) 60 parts, terpene phenol resin (softening point 91°C) 20 parts, polyvinyl acetate (softening point 131)
℃) and 10 parts of butadiene-acrylonitrile copolymer were melt-mixed in an inner layer extruder and supplied to a blow extrusion die (die temperature 220℃).
Maleic anhydride graft modified polyethylene (specific gravity 0.92, MI=1.3g/10min
Maleic anhydride (0.9 mol %) was melted and fed to a blow extrusion die. For the outer layer, use an extruder to produce ethylene-vinyl alcohol copolymer (35 mol% ethylene, degree of saponification 99.7 mol%, MI = 6 g/10 min)
was melted and supplied to the blow extrusion die. Each resin flows concentrically within the coextrusion die, and is laminated within the die to form a three-layer blow parison, blowing 100 c.c. into the parison at a pressure of 6 kg/cm ² and a diameter of 30 mm.
Form a 200mm long cylindrical broach tube with
A tube container was obtained by cutting the bottom. Example 2 The following mixture was melted in the inner layer extruder of Example 1, and a tube was obtained in the same manner. Ethylene, vinyl acetate copolymer (vinyl acetate 25
Weight%, specific gravity 0.943, MI = 2) 60 parts, ethylene vinyl alcohol copolymer (specific gravity 1.13, MI = 13,
Ethylene content 78 mol%, saponification degree 75 mol%) 20
Part, hydrogenated cyclopentadiene resin (softening point
A mixture of 10 parts of oxidized wax (oxidation degree 22-28, saponification degree 50-60, m.p 92℃, penetration degree 5-7) was melt-extruded using an extruder for inner layer. . Example 3 A tube was made in the same manner as in Example 1. The inner layer is Surlyn A (2n type MI = 1.5 specific gravity 0.95, m.
p=910℃) 50 parts, 6/66 copolymerized nylon (6 nylon 15%) 20 parts, aliphatic hydrocarbon (softening point 70
℃, specific gravity 0.97, molecular weight 1000-2000) 10 parts, ethylene vinyl alcohol copolymer (ethylene 35 mol%, saponification degree 99 mol%, MI = 6-8 g/10 min
mp = 182°C) 20 parts of the mixture was melted in an extruder for inner layer to make a tube. Example 4 Polyethylene for inner layer (specific gravity 0.92, MI=1.3)
80 parts, polyethylene oxide (molecular weight 50-70
A tube similar to that in Example 1 was made using a mixture of 10 parts of dimeric acid type polyamide (softening point: 65-67°C) and 10 parts of dimer acid type polyamide (softening point: 125°C). Example 5 The laminated parison of Example 1 was continuously extruded and cut into pieces with an outer diameter of 30 mm and a length of 200 mm to form a tube body, and then a tube head was formed by injection molding of low-density polyethylene. At the same time, the two were heat-fused to make a tube container. Example 6 6/66 nylon copolymer (6 nylon
A tube was molded in the same manner as in Example 1 using 15 ^W %, m.p 185°C). Next, a comparative example will be described for comparison with this. Comparative Example 1 Polyethylene (specific gravity 0.92 MI=
Everything was the same as in Example 1 except that 1.3) was melted and fed to the die. Comparative Example 2 A tube was made which was exactly the same as in Example 2 except that an ethylene-vinyl acetate copolymer (vinyl acetate 25%, specific gravity 0.92, MI=1.3) was melted in an inner layer extruder. Comparative Example 3 Surlyn A was melted in an inner layer extruder and a tube was obtained in exactly the same manner as in Example 3. Comparative Example 4 Polyethylene (specific gravity 0.92, MI=
A tube was molded in the same manner as in Example 5 except that 1.3) was used. Comparative Example 5 A tube was molded in the same manner as in Example 6 using polyethylene (specific gravity 0.92, MI=1.3) for the inner layer. The above tubes were tested for toothpaste storage stability, fragrance retention, wetting of the inner wall of the tube with toothpaste, and heat sealability of the bottom of the tube, and the results are shown in the following table. However, 〇...Excellent △...Good ×...Poor In each case, the inner layer is 350μ, the middle layer is 50μ, and the outer layer is 50μ.

[Table] As mentioned above, the transparent extruded tube container of the present invention has an innermost layer mainly composed of a hydrophilic resin and a hydrophobic resin mixed therein. Excellent holding power, hardness and flexibility as a layer. Furthermore, it is mixed with oxidized wax to make it easier to wet with water and the contents, and a tackifying agent to improve adhesion with the contents and prevent the contents from cracking. It has good compatibility with the contents of cosmetics, etc., and has good wettability, adhesion, and affinity between the contents and the inside of the tube, and does not cause cracks in the contents, so it has a good appearance even if the container is transparent. The tube is transparent, which allows you to directly see the condition of the contents, increases purchasing power, and fully enhances the in-store effect.The tube's special multi-layered structure also provides gas barrier properties, moisture resistance, and fragrance retention. This tube has excellent oil resistance and chemical resistance. Moreover, it has the advantage that the bottom can be heat-sealed at a low temperature.

Claims (1)

[Claims] 1. In an extruded plastic tube container with excellent transparency, the innermost layer is a uniform layer of a mixture of 5-50 ^W % of hydrophilic resin and oxidized wax, 95-50 ^W % of hydrophobic resin, and a small amount of tackifier. An extruded tube container with excellent transparency, characterized in that at least one of the middle layer or the outermost layer is a gas barrier resin layer, and is highly compatible with the contents and has high wettability.