JP2003094539A - Multilayer plastic vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer plastic vessel being excellent in a drop impact strength and having a surface gloss, in regard to a thermoplastic plastic vessel having a multilayer structure, particularly a profile vessel of an oval shape or the like. SOLUTION: In regard to the plastic vessel of which the barrel part 1 of the vessel main body except a mouth part 2 has a width and a thickness in the ratio of 1.3 or above between them, the vessel is constituted of two layers of a polyethylene resin, at least, and the density of the polyethylene resin of the outermost layer is 0.93-0.95 g/cm<3> , while that of the polyethylene resin of the layer inside it is 0.95 g/cm<3> or above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic plastic container having a multi-layer structure, and more particularly to a multi-layer plastic container having excellent drop impact strength and surface gloss.

[0002]

2. Description of the Related Art Plastic containers are lightweight and therefore easy to handle and easy to dispose of after use, and are used for various purposes such as beverages and toiletries. Especially for toiletries and cosmetics, polypropylene containers having a glossy outer layer are often used because they are easily noticed in stores.

[0003]

However, due to recent environmental problems and the enforcement of the Container Recycling Law, reduction of waste is required, and it is desired to reduce the weight of plastic containers as well. The polypropylene container described above has poor impact strength when the weight of the container is reduced due to the characteristics of the resin, cracks occur during transportation, or damage occurs when dropped, and there is a problem in content protection. In particular, this tendency was more noticeable in an odd-shaped container such as an oval shape in which the thickness distribution differs in the cross-sectional direction and a thin portion is formed, as compared with a cylindrical container. The present invention provides a thermoplastic container having a multilayer structure,
In particular, it is to provide a multi-layered plastic container which has excellent drop impact strength and has a surface gloss in the case of a deformed container such as an oval shape.

[0004]

The present invention has been made to solve the above problems, and a multilayer plastic container according to claim 1 has a width and thickness ratio of the container body excluding the mouth portion of 1 In a plastic container of 3 or more, the density of the outermost polyethylene resin is 0.93 g / cm 3 or more and is 0.95 g, which is composed of at least two layers of polyethylene resin.
/ Cm3 or less, and the density of the polyethylene resin in the inner layer is 0.95 g / cm3 or more.

A multi-layer plastic container according to a second aspect of the present invention is the multi-layer plastic container according to the first aspect, wherein the outermost polyethylene resin is mixed with pearl essence. .

A multi-layer plastic container according to claim 3 of the present invention is the multi-layer plastic container according to claim 1 or 2, wherein an intermediate layer containing a colorant is provided between the outermost layer and the inner layer. It is a multilayer plastic container characterized by being formed.

A multi-layer plastic container according to a fourth aspect of the present invention is the multi-layer plastic container according to the third aspect, wherein the intermediate layer contains recycled material in a ratio of 50% or less. It is a plastic container.

A multilayer plastic container according to claim 5 of the present invention is the multilayer plastic container according to any one of claims 1 to 4, wherein the outermost surface of the multilayer plastic container has a thickness of 120 μm or less. A multilayer plastic container characterized in that a label is attached by a method of applying a label in a mold.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the shape of the multi-layer plastic container of the present invention, the flatness of the entire container excluding the mouth portion is 1.3 or more. More specifically, the container has an oval form in which the average of the width and thickness of the container from the bottom of the mouth to the shoulder, the body, and the bottom ground contact surface is 1.3 or more. For containers with a low flatness and close to a perfect circle (flatness of less than 1.3), the difference in wall thickness in the cross-sectional direction is small and thin parts do not occur or are unlikely to occur. Excellent, not limited to the present invention.

The polyethylene used for the outermost layer of the multi-layer plastic container of the present invention has a density of 0.93 g / cm3.
As described above, it is 0.95 g / cm 3 or less, and since it is flexible, the mold transfer property is good and the gloss is excellent. Density is 0.95
When it exceeds g / cm 3, the mold transfer property is slightly inferior, and when it is less than 0.93 g / cm 3, the transfer property is good, but the surface hardness is poor and it is easily scratched. The outermost layer ratio should be as thin as possible to maintain bottle strength. 2
0% or less is desirable.

As the pearl essence compounded in the outermost layer of the container, conventional mica or mica coated with titanium oxide or iron oxide is used, and light is reflected outward by the action of pearl essence to give a pearly luster. Presents the appearance of.

Further, an intermediate layer may be newly formed between the outermost layer of the container and the inner layer, and may be colored.
It is no problem to mix recycled materials such as burrs generated in the production of plastic containers in a ratio of up to 50% (weight%) for the reason of maintaining extrusion stability. However, the base resin of the intermediate layer has a density of 0.95 because of maintaining the strength of the bottle.
Polyethylene of g / cm3 or more is desirable.

The multi-layer plastic container of the present invention can be decorated with an in-mold label, and the thickness of the label to be used is 120 μm or less, and preferably 80 μm to 100 μm in consideration of cost and handling.

[0014]

The multi-layer plastic container of the present invention can maintain sufficient strength because it is made of polyethylene against insufficient strength (mainly drop impact strength) due to reduction of the amount of resin in irregularly shaped containers such as oval shape, The polyethylene resin in the outermost layer of the container has a density of 0.93 g / cm 3 or more, 0.95 g /
Since it is not more than 3 cm3, it is possible to supply a gloss bottle having a good balance of glossiness and surface hardness and having no scratch. Further, when pearl essence is added to the outermost layer, a pearly gloss bottle can be obtained, and it is possible to newly form the intermediate layer and add a coloring material or a recycled material.

[0015]

EXAMPLES Next, examples of the present invention will be specifically described. The oval-shaped containers shown in FIGS. 1 and 2 were manufactured by multi-layer blow molding in the shapes, volumes, and layer configurations of the containers of Examples 1 to 5 and Comparative Examples 1 and 2 shown in Table 1. The container having the container shape A in FIG. 1 is composed of a container body 1 (side wall portion), a mouth portion 2 and a bottom portion 3, and the container shape A is the width of the body portion 1 when viewed from the front (or back) thereof. The ratio (flatness) of w1 and the width w2 of the body portion 1 as viewed from both left and right sides = w1 /
The w2 is 1.3, the volume is 600 ml, and the weight is 30 g. The container having the container shape B shown in FIG. 2 is composed of a container body 1 (side wall portion), a mouth portion 2 and a bottom portion 3.
The ratio of the width w1 of the body 1 as viewed from the front (or the back) to the width w2 of the body 1 as viewed from the left and right sides (flatness) = w1 / w2 is 1.5, and the capacity is Is 60
It is 0 ml and weighs 30 g. Table 2 shows the measurement results of the surface glossiness and the drop strength of the container shapes A and B obtained in Examples 1 to 5 and Comparative Examples 1 and 2, respectively. <Examples 1 to 3> The oval-shaped container (container shape A) shown in FIG.
It was produced in the shape, volume, and layer configuration of the container of No. 3 to No. 3. <Example 4> An oval-shaped container (container shape B) shown in Fig. 2 was produced by multi-layer blow molding in the shape, volume and layer configuration of the container of Example 4 shown in Table 1. <Example 5> An oval-shaped container (container shape B) shown in Fig. 2 was produced by multi-layer blow molding in the shape, volume and layer configuration of the container of Example 5 shown in Table 1. In addition, Example 5
Then, at the time of forming the oval-shaped container (container shape B) shown in FIG. 2, a 90 μm label was placed in the mold, and the label 10 was attached in the range shown by the dotted line in FIG. Label 1
The composition of 0 is 90 μm of unstretched polypropylene (CPP)
/ Heat seal lacquer (EVA system, coating amount 3g / m2
).

<Comparative Example 1> An oval-shaped container (container shape A) shown in FIG. 1 was produced by multi-layer blow molding in the shape, volume and layer structure of the container of Comparative Example 1 shown in Table 1.

<Comparative Example 2> As in Comparative Example 1 above, FIG.
The oval-shaped container (container shape A) shown in FIG. 2 was subjected to multilayer blow molding to obtain the shape, capacity, and volume of the container of Comparative Example 2 shown in Table 1.
It was produced in a layer structure.

[0018]

[Table 1]

[0019]

[Table 2]

[Glossiness Measurement Method] The glossiness was measured based on JIS-Z7105 test conditions (60-degree specular glossiness). [Drop test method] According to JIS-Z0202. After storing the containers filled with the specified amount of water at 5 ° C for 24 hours, 10 containers were placed vertically on the concrete from a height of 1 m.
Drop it once and check for cracks in the container. The number of cracks in the drop test results is 1 to 5 for each example and 1 to comparative example.
When each of the 10 containers obtained in 2 was dropped, the number of cracks in 10 was displayed.

From the above results, Examples 1 to 5 showed a high glossiness of 40%, and no damage due to dropping was observed, which was good. In Comparative Example 1, no drop damage was observed, but the gloss was inferior, and in Comparative Example 2, drop damage occurred contrary to Comparative Example 1.

[0022]

The multilayer plastic container of the present invention has the outermost layer of 0.93 g / cm3 or more and 0.95 g / cm3.
The following polyethylene, 0.95g in the inner layer than the outermost layer
The use of polyethylene of at least 3 cm3 / cm3 makes it possible to obtain a container having excellent surface gloss, strong drop impact strength, scratch resistance and excellent performance and appearance, and recycled to the intermediate layer. By forming a material-containing layer, it is possible to reduce the waste of materials, and in a thermoplastic container having a multi-layered structure, especially in a deformed container such as an oval shape, it has excellent drop impact strength and good surface gloss. There is an effect that a multi-layer plastic container having

[Brief description of drawings]

FIG. 1 (a) is a front view showing an example of a container shape in a multilayer plastic container of the present invention, and FIG. 1 (b) is a side view thereof.

FIG. 2 (a) is a front view showing another example of the container shape in the multilayer plastic container of the present invention, and FIG. 2 (b) is a side view thereof.

[Explanation of symbols]

A ... Container shape of oval container B ... Container shape of oval container w1 ... Width of body part when the container is viewed from the front w2 ... Width of body part when the container is viewed from the side 1 ... Container body part 2 ... Container mouth part 3 ... Container bottom 10 ... In-mold label

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3E033 BA15 BB04 BB05 BB08 CA03                       CA20 DA03 DB03 DD05 DE20                       EA20 GA02                 4F100 AK01C AK04A AK04B BA02                       BA03 BA07 BA10A BA10B                       BA25 CA13 EH20 EH202                       GB16 JA13A JA13B JK10                       JL10C JL16C JN21 JN21A                       YY00A YY00B

Claims (5)

[Claims] 1. The width-thickness ratio of the container body excluding the mouth is
In a plastic container of 1.3 or more, it is composed of at least two layers of polyethylene resin, and the density of the polyethylene resin of the outermost layer is 0.93 g / cm 3 or more and 0.95 g / c or more.
A multi-layer plastic container characterized in that the density of the polyethylene resin in the inner layer is m3 or less, and the density of the polyethylene resin in the inner layer is 0.95 g / cm3 or more. 2. The multi-layer plastic container according to claim 1, wherein pearl essence is mixed with the polyethylene resin of the outermost layer. 3. The multilayer plastic container according to claim 1, wherein an intermediate layer containing a colorant is formed between the outermost layer and the inner layer. 4. The multilayer plastic container according to claim 3, wherein the recycled material is contained in the intermediate layer in a ratio of 50% or less. 5. A label having a thickness of 120 μm or less is attached to the outermost layer surface of the multi-layered plastic container by a method of applying a label in a mold, according to any one of claims 1 to 4. The multi-layer plastic container according to the item.