JPS60228237A - Multilayer vessel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multilayer container, and more particularly to a multilayer container that has extremely good printability on the surface of the container and is excellent in moldability, rigidity, and strength.

Conventionally, containers made of thermoplastic resins containing relatively large amounts of inorganic fillers have been widely used, especially as blow-molded containers, due to their low calorie burn during incineration and excellent rigidity. However, when producing containers by thermoforming such as vacuum forming using sheets of these thermoplastic resin compositions, there are problems such as surface roughness due to extrusion during sheet production, difficulty in deep drawing, and difficulties in forming the sheets, especially when heated at relatively low temperatures. In the case of molding, the inorganic filler contained therein is exposed on the surface, resulting in deterioration of surface properties.

Furthermore, when printing on the surface of these containers, especially when printing containers with a circular cross-sectional shape at high speed and continuously using a curved surface printing machine, the inorganic filler exposed on the blanket part that comes into contact with the container is transferred, This transfers to the plate, roller, and ink over time, making it impossible to stably obtain beautiful printing over a long period of time.

Therefore, the inventors of the present invention conducted intensive research to develop a container that can print beautifully for a long period of time and has excellent moldability, rigidity, and strength.As a result, a container made of a specific resin laminate was developed. It was found that the present invention is suitable for the purpose, and the present invention was completed based on this finding.

That is, in the present invention, the inner layer is a resin composition layer containing 30 to 80% by weight of a thermoplastic resin and 70 to 20% by weight of an inorganic filler, and the outer layer is a resin composition layer containing only a thermoplastic resin or an inorganic filler content of 10% by weight or less. This is a multilayer container consisting of a thermoplastic resin composition layer.

In the present invention, various types of thermoplastic resins can be used without particular limitation as the thermoplastic resin in the thermoplastic resin composition for the inner layer of the container. Specifically, polyethylene,
Examples include polypropylene, polyvinyl chloride, polystyrene, polyester, acrylonitrile-styrene resin, styrene-butadiene block copolymer, and mixtures thereof. Particularly preferred are polyolefin resins such as polyethylene resins and polypropylene resins, and polystyrene resins. When polyolefin resin is used here, polyethylene resin is used.

Polypropylene resins or polybutene resins may be used alone or may be mixed appropriately, but in order to continuously mass produce the multilayer container of the present invention by secondary forming such as vacuum forming or pressure forming, It is effective to use a mixture of polyethylene resin and polypropylene resin. The mixing ratio of polyethylene resin and polypropylene resin in this mixture is not particularly limited, but generally the former:latter = 9 = 1 to 1:9 (weight ratio), preferably 7:
3 to 3 nia (weight ratio).

Various inorganic fillers can be used, such as talc, titanium oxide, calcium carbonate, magnesium carbonate, kaolin, clay, calcium sulfite, aluminum hydroxide, barium sulfate, magnesium carbonate, or mixtures thereof. Hardware etc. can be used. Particularly suitable is talc alone or a mixture of talc and titanium oxide.

When using Merck here, talc is its type.

There are no particular restrictions on the shape, etc., but it is usually hydrated magnesium silicate with an average particle diameter of 5 to 30 μm, preferably 10 to 20 μm, and its composition is SiQ.

It consists of 50-65% Mg, 25-40% Mg and other components, and has a loss on ignition of 1% or less.

As mentioned above, various types of talc can be used, such as highly refined talc,
Alternatively, it is also possible to use one that has been treated with an acid to remove impurities. Note that this talc does not require any additional means such as surface treatment.

Furthermore, when titanium oxide is used as an inorganic filler together with Merck, the titanium oxide is usually titanium dioxide (T10
□), but a small amount of titanium oxide ('t
'io) or dititanium trisunide (Ti*oa) may be used. In addition, there are no particular restrictions on the shape etc. of this titanium oxide, but it is generally granular with an average particle size of 0.05 to 2μ, preferably about 0.1 to 1μ.
It is in powder form, etc.

The resin composition of the inner layer is a thermoplastic resin 30 to 80% as described above.
It is obtained by blending and kneading % by weight, preferably 35-70% by weight, and 70-20% by weight, preferably 65-30% by weight of an inorganic filler. When the blending ratio of the inorganic filler exceeds 70% by weight, moldability deteriorates, and
If it is less than % by weight, it is not preferable because the rigidity and disposal properties are poor. In addition, when talc and titanium oxide are used together, the proportion t- of titanium oxide is 0.5 with respect to the resin composition.
-10% by weight, preferably 1-6% by weight.

Next, the material for the outer layer of the multilayer container of the present invention is a thermoplastic resin alone or a thermoplastic resin composition having an inorganic filler content of 10% by weight or less. The thermoplastic resin here is not particularly limited, and may include those shown for the inner layer, and the resins for the inner layer and outer layer may be the same or different, but it is usually preferable to use the same resin. It is.

In addition, the same inorganic fillers as those shown for the inner layer can be mentioned, and they may be the same as or different from the inorganic filler used in the inner layer, but Merck is particularly preferred. . The material for the outer layer is a thermoplastic resin alone or a thermoplastic resin mixed and kneaded with an inorganic filler in a proportion of 10% by weight or less.

If the content of the inorganic filler exceeds 10% by weight, the surface properties of the container will deteriorate and beautiful printing cannot be stably performed on the surface of the container for a long period of time.

In addition, in the present invention, if necessary, rubbers such as ethylene-propylene rubber and ethylene-propylene-diene rubber are added to the components of the inner layer and/or outer layer.
It is also possible to add polyolefin resins modified with unsaturated carboxylic acids such as maleic anhydride or derivatives thereof.

In addition, various antioxidants, ultraviolet absorbers, antistatic agents,
It is also possible to add lubricants, pigments, etc.

The multilayer container of the present invention consists of the inner layer and outer layer as described above, and the layer thickness ratio of the inner layer and the outer layer is not particularly limited, and may be appropriately selected and determined depending on the type and amount of the resin and inorganic filler used. Normal layer thickness ratio is inner layer: outer layer = 98-70
:2-30, preferably 97-80:3-20.

Further, the average wall thickness of the container is about 0.3 to 0.8 m.

The container of the present invention basically consists of the above-mentioned inner layer and outer layer, but other layers may be laminated as necessary.

For example, an adhesive resin such as saponified ethylene-vinyl acetate copolymer, nylon, polyethylene terentalate, or unsaturated carboxylic acid-modified polyolefin may be laminated as an intermediate layer between the inner layer and the outer layer, or an adhesive resin such as saponified ethylene-vinyl acetate copolymer, nylon, polyethylene terentalate, or unsaturated carboxylic acid-modified polyolefin may be laminated as an intermediate layer between the inner layer and the outer layer. A thermoplastic resin having an inorganic filler content of 10 weight λ or less may be laminated as the innermost layer.

The container of the present invention can be manufactured by various methods,
There are no particular restrictions. For example, a laminate sheet having an inner layer and an outer layer as described above can be formed by a calender method, a T-die method, etc., and then a desired container can be obtained by thermoforming such as vacuum forming or pressure forming. In the present invention, the shape of the multilayer container is not particularly limited, and it is a deep container having a height/average diameter or average side length of 1 or more.

Usually, a cup-shaped one used for drinking, as shown in FIG. 1, is suitable. This is a deep container with a circular cross section and is extremely moldable and can be produced continuously. The opening of the molded container is preferably curled to improve its strength, safety, and the like.

Since the multilayer container of the present invention uses at least two layers of laminates in its manufacture, it has excellent moldability, especially the moldability of deep containers, and the resulting container also has good dimensional stability. Also, whether the outer layer of the container does not contain inorganic fillers,
In addition, since it is a material containing only a relatively small amount, the surface is less rough when forming sheets or containers. Therefore, when printing on the surface of a container, there is an advantage that beautiful printing without unevenness or fading can be achieved over a long period of time. Furthermore, the rigidity and strength as a container are also good, and the environmental stress cracking resistance (IC8OR) is also high.

In addition, the multilayer container of the present invention has high stain resistance on the container surface,
Furthermore, when Merck or a mixture of Merck and titanium oxide is used as the inorganic filler, the product has a high-quality paper-like appearance.

Therefore, the multilayer container of the present invention can be effectively used for various food containers including beverage containers for vending machines.

Next, the present invention will be explained in detail with reference to Examples.

Examples 1 to 5 and Comparative Examples 1 to 3 After molding a two-layer or single-layer sheet with a thickness of 1.2 MX and a width of 500 nm using a coextrusion T-die sheet manufacturing apparatus using the resin and layer ratio shown in Table 1. A container with a diameter of 75 mm, a bottom diameter of 5 degrees, and a height of 80 m was molded using a continuous vacuum-pressure forming machine at a sheet temperature of 150'C.

Table 1 shows the evaluation results of the strength, appearance (paper-like texture), and printability of the obtained containers.

/

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an example of the multilayer container of the present invention. 1...Inner layer 2...Outer layer Patent applicant Idemitsu Petrochemical Co., Ltd. Figure 1 procedural amendment (voluntary) June 14, 1980 Commissioner of the Japan Patent Office Kazuo Wakasugi Tono 1, Patent application for indication of the case 1982- 7' 5024 2. Name of the invention Multi-layer container 3. Relationship with the person making the amendment Patent applicant Idemitsu Petrochemical Co., Ltd. 4. Agent ■ 104 Address 5 Nishikan Building, 1-1-10 Kyobashi, Chuo-ku, Tokyo Floor name (7407) Patent attorney Kubo 1) Fujibe Telephone (27)
5) No. 0721 No. 5, Detailed explanation of the invention column 6 of the specification subject to amendment, page 11 of the specification of contents of the amendment, 4th row from the right in the top column of Table 1.
Correct "layer ratio (outer layer/inner layer)" to (inner layer/outer layer). (that's all)

Claims (5)

[Claims] (1) The inner layer is a resin composition layer containing a thermoplastic resin of 30 to 80% by weight and an inorganic filler of 70 to 20% by weight, and the outer layer is a thermoplastic resin alone or the inorganic filler content is 1.
A multilayer container comprising a thermoplastic resin composition layer containing 0% by weight or less. (2) The multilayer container according to claim 1, wherein the container is thermoformed. (3) The multilayer container according to claim 1, wherein the container is a deep container having a height/average diameter or average side length of 1 or more. (4) The multilayer container according to claim 1, wherein the cross-sectional shape of the container is circular. (5) The multilayer container according to claim 1, wherein the peripheral edge of the container opening is subjected to a curling treatment.