JPH0472132A - Vessel having rough interior surface made of crystalline thermoplastic resin - Google Patents

Abstract

PURPOSE:To provide a vessel which is made transparent only when contents are put into the vessel by making total haze and internal haze of the wall a specified value respectively in the case of a vessel having a rough internal surface and a smooth external surface. CONSTITUTION:A vessel made of crystalline thermoplastic resin is provided, which has a rough interior surface such that total haze of wall is 50% or higher and internal haze of wall is 10% or lower. Crystalline propylene simple polymer or copolymer having boiling heptane extraction residue of 70 wt.% or more and MFR(230 deg.C; 2.16 kgf) 0.1-g/10 min is employed as crystalline thermoplastic resin. Since the wall has a rough surface and total haze thereof is as high as 50-90%, the wall is opaque, whereas internal haze is as low as 0.5-10%, which provides transparency. Therefore, when any contents in a wet state such as liquid or viscous matter etc., are brought into contact with the rough surface of the interior of the vessel, rough state of the surface is eliminated, with the result that the contents can be easily seen from the outside of the vessel.

Description

[Detailed Description of the Invention] [Industrial Application Field] An object of the present invention is to provide a container which has excellent mechanical strength and whose inner wall surface is made transparent by the contents so that the contents can be seen from outside the container. With the goal. Furthermore, the container of the present invention has the advantage that information recorded on the opaque portion can be easily identified.

[Prior Art] Transparent containers molded from resins with excellent transparency such as polystyrene resin and polyvinyl chloride resin are already widely used.However, these resins lack heat resistance, hygiene and There is still room for consideration in terms of the impact of incineration on environmental conservation, etc.Also, although containers made of crystalline thermoplastic resins such as polypropylene and high-density polyethylene are advantageous in the above points, Even if it is a transparent container,
Even though the container was opaque, the inner wall surface was hardly made transparent by the contents.

However, depending on the use of the container, it is desirable that the container wall be made transparent by filling the container with contents, so that it can be seen from outside the container. This type of request is surprisingly common. The legibility of the contents on the container wall is also important.

[Problems to be Solved by the Invention] An object of the present invention is to provide a container whose wall becomes transparent for the first time depending on the contents. That is, the container is opaque or translucent when it contains no contents.

[Means for Solving the Problems] The present inventors have completed the special container described below as a means for solving the above problems.

In a container made of a crystalline thermoplastic resin, the inner wall surface of the container is rough and the outer wall surface is smooth, the total haze of the wall is 50% or more, and the internal haze of the wall is 10% or less. A crystalline thermoplastic resin container having a rough inner surface, characterized by the following.

Examples of the crystalline thermoplastic resin used in the present invention include the following: - Crystalline olefin polymer: crystalline propylene homopolymer, crystalline propylene/ethylene, or one type containing 4 or more carbon atoms The above 1-olefin copolymers (1-olefin component content of 50 mol% or more), such as: crystalline propylene/1-butene copolymer, crystalline propylene/l-hexene copolymer, crystalline propylene/1 −
Among the octene copolymer, crystalline propylene/1-decene copolymer, and the above-mentioned crystalline propylene homopolymer or copolymer, MFR ( 230℃; 2.16kgf)
0.1-10 g/10m1n, preferably 0.3-10 g/10m1n
6 g/10ml is used.

・Crystalline ethylene homopolymer, crystalline ethylene ・One or more 1-olefin copolymers containing 3 or more carbon atoms (ethylene component content 50 mol% or more), for example: crystalline ethylene propylene copolymer Coalescence, crystalline ethylene/1-butene copolymer, etc.: Among the above crystalline ethylene homopolymers or copolymers, those with a density of 0.
920-0.965 g/ml, preferably 0.940
~0.960g/ml and Ml (190°C, 2.16
kgf) O, 1 to 10 g/10 m1n, preferably 0.3 to 0.5 g/10 m1n.

・Crystalline polyamide resin: Crystalline 6-nylon, crystalline 6.6-nylon, crystalline 6.10-nylon, crystalline 6.11-nylon, crystalline wholly aromatic polyamide resin, etc.; ・Crystalline polyester resin : Crystalline ethylene glycol (or ethylene oxide)
- Terephthalic acid cocondensate (PET), crystalline 1,4-butanediol/terephthalic acid cocondensate (PBT), crystalline wholly aromatic polyester resin, etc.

In the present invention, the resin layer forming the container is required to be highly transparent, that is, its internal haze is 10% or less. Rolling treatment can be cited as an effective means for achieving this.

In other words, a film-like material or a sheet-like material (
A suitable method is to cold-roll a sheet (hereinafter collectively referred to as a "sheet-like material") below the crystalline melting point (defined later) of the resin, and in this case, the rolling reduction ratio (r) of the resin layer is 30% or more, Preferably it is set to 40% or more.

r= (h, -hs)/h, An improvement is achieved such that the internal haze is reduced by a factor of 3 to 5 and about 1/10.

As a result, the surface of the rolled sheet of crystalline thermoplastic resin obtained is smooth, and the internal penetration is 4110% or less, preferably 5% or less, and more preferably 3% or less.

The final thickness of the rolled planar body that is the raw material for the container of the present invention is usually 0.05 to 20 mm, preferably 0.1 to 10 mm.
Adjust to.

The crystalline melting point of the resin in the rolling process of the present invention is defined by JIS
It refers to the temperature at which the maximum peak of the thermal behavior curve of the resin is obtained using a DSC (differential scanning calorimeter) in accordance with K7121. In addition, when a plurality of peaks exist, the temperature at which the peak having the largest area among them is located is taken as the crystal melting point of the resin.

The container of the present invention is required to have a rough inner wall surface and a smooth outer wall surface. The different states of each surface will be specifically explained below.

The condition of the smooth surface located on the outside of the container is as follows: In terms of surface roughness (JIS BO601-1982), it is 0.5S or less, preferably 0.2S or less.

A gloss level of 70% or more is preferable from the viewpoint of commercial value.

The inner surface of the vessel is a rough surface, for example, satin-like, and has a total height of 50 mm.
% or more, preferably 55% or more.

In the container of the present invention, since the inner wall surface of the container is rough, the container is so opaque that its total haze reaches 50 to 90%.

On the other hand, in the container of the present invention, the internal haze is slightly 0.
, 5 to 10%. This is due to the fact that the internal haze is significantly reduced by rolling during the sheet material stage.

Therefore, when the contents in a moist state such as liquid or viscous come into contact with the rough surface located on the inside of this container, the rough surface disappears, making it possible to easily see through the contents from the outside of the container. Become.

In order to make the transparency by the hydrophilic contents more effective, it is effective to subject the rough surface to an activation treatment, such as a corona discharge treatment or a chemical oxidation treatment.

<Preparation of material sheet-like product> Various methods can be adopted as a method for producing the above-mentioned material sheet-like product of the present invention, including the following methods3, 3.1. When rolling a material sheet with a pair of rolls or caterpillars that rotate in opposite directions, one of them is sandwiched between a mirror-finished roll or caterpillar and the other with a matte roll or a matte-finished caterpillar combination system. , a method in which rolling and surface roughening are performed simultaneously; 3.3.2 After forming a transparent sheet by rolling the material sheet with a pair of mirror rolls or mirror caterpillars that rotate in opposite directions, one side of the sheet is rolled. For example, methods for roughening the surface by the following treatments: - Thermal treatment: Instantly blowing a high-temperature gas higher than the melting point of the material resin; - Chemical treatment: Treating the material resin with a chemical that can dissolve or swell;・Mechanical treatment: Scratches are removed by rubbing with a brush roll, sanded roll, etc.; Scratches are removed by sand blasting, shot blasting, etc.; Scratches are removed by sand blasting, shot blasting, etc.; Transfer by pressing through a hard material with a rough surface: Transfer by sandwiching between a pair of mirror/matte finish rolls or caterpillars that rotate in opposite directions.

Among the above-mentioned surface roughening treatments, mechanical treatment is practical as a treatment for imparting the desired surface condition to the sheet material forming the container of the present invention. In particular, it is preferable to use a roll or pressure plate that has been subjected to shot processing of 50 to 1000 meshes, preferably shot processing of 100 to 600 meshes, as the rough surface roll.

Various known methods can be used to form the containers of the invention: for example, conventional aging methods such as vacuum forming, pressure forming, sheet blow molding or hot stamping.

[Preferred embodiment Test method - Haze: ASTM-01008 - Tensile strength: JIS-7113 - Buckling strength: Place a plate on the upper edge of the molded product and test at a speed of 50+nm/min using a Tensilon compression tester・Container wall thickness: Average value obtained by cutting open the side wall of the container and measuring the thickness at 5 points ・Container bottom thickness: 5 points at the bottom Average thickness of ・Contents transparency Pour water up to 30 mm from the bottom of a two-cup molded product, and place three sticks of red, blue, and yellow, each with a diameter of 5IIlffl, in the water in the center of the cup. Observation from the outer wall of the cup O The shape and color of the rod can be clearly distinguished X The shape and color of the rod are blurred or cannot be distinguished at all Examples 1 to 4 16kgf)
0.7 g/10m1r+) ] by T-die extrusion molding method (extrusion temperature 250°C, chill roll temperature 60°C) into sheets for rolling (each thickness 0.6.09.1.
2 mm, 0.5 mm, and a width of 250 mm). These sheets were then passed through a pair of rolling rolls [diameter 300 mm
The length of the X surface is 400 mm, the surface temperature is 130°C, one side is a mirror-finished roll (surface roughness 0.2 S), the other is a rough-faced roll (200 mesh shot blast finish), and the For various reduction blades, speed 2 m/
Rolling was carried out at a speed of 10 min to obtain 4 types of rolled sheets for thermoforming (each 0.3 mm thick, one side having a mirror surface and the other surface having a rough surface).

The measurement results for each sheet are shown in Table 1.

Each sheet was heated for 30 seconds using a far-infrared radiant heater to bring the sheet temperature to 150°C.

Next, 3.5 kg was formed using the plug-assisted pressure forming method.
Under a pressure of f/cm2, a rolled sheet for thermoforming was placed in a molding device with its rough side facing inside the container, and molded to form a cup-shaped molded product (opening diameter 60 mm x bottom diameter 50 m).
m, depth 40 mm) was obtained. The measurement results of this molded article are shown in Table 1.

Comparative Example 1 Using the same resin as in Examples 1 to 4, a sheet for rolling (thickness O, dmm x width 250 mm) was made using the T-die extrusion molding method (extrusion temperature 250°C, chill roll temperature 60°C), The sheet was rolled in the same manner as in Examples 1 to 4, except that the rolling reduction ratio was changed.
The thickness was 0.3 mm and the width was 250 mm). This rolled sheet was thermoformed in the same manner as in Examples 1 to 4 to obtain a cup-shaped molded product. Table 1 shows the measurement results of the rolled sheet for thermoforming and the obtained molded product.

Comparative Example 2 A thermoforming sheet (thickness 0.3+nm x width 250 mm) was made using the same resin as in Examples 1 to 4 by T-die extrusion molding (extrusion temperature 250°C, chill roll temperature 60°C). Thermoforming was then carried out in the same manner as in Example 1, except that rolling was not performed.

Table 1 shows the measurement results of the non-rolled sheet for thermoforming and the obtained molded product.

Example 5 High-density homopolyethylene: / E MI (190'C,
2,16 kgf) 0.4/10 m1n] by T-die extrusion method (extrusion temperature 240°C, chill roll temperature 60”C)
A sheet for rolling (thickness: 0.9 mm x width: 250 mm) was obtained. Next, thermoforming was carried out in the same manner as in Example 2 except that the surface temperature of the rolling roll was 100'C1 and the temperature of the rolled sheet for thermoforming during the subsequent aging molding was 110'C, to obtain a cup-shaped molded product. Obtained. Table 1 shows the measurement results of the rolled sheet for ripening and the obtained molded product.

Comparative Example 3 Aging molding was carried out in the same manner as in Comparative Example 2, except that the same resin as in Examples 1 to 4 was used, and the extrusion temperature, chill roll temperature, and sheet temperature during thermoforming were the same as in Example 5. A cup-shaped molded product was obtained. Table 1 shows the measurement results of the unrolled sheet for ripening and the molded product.

Example 6 T-die extrusion molding method (extrusion temperature 270°C, chill roll temperature 80°C) using commercially available nylon-6 (specific gravity 1.14)
A sheet for rolling (thickness 0.9 mm x width 250
mm), then the surface temperature of the rolling roll was set to 160°C,
The temperature of the rolled sheet for thermoforming during subsequent thermoforming was set to 17
Aging molding was carried out in the same manner as in Example 2 except that the temperature was 0° C. to obtain a cup-shaped molded product. Table 1 shows the measurement results of the rolled sheet for ripening and the obtained molded product.

Comparative Example 4 A cup-shaped molded product was obtained by thermoforming in the same manner as in Comparative Example 2 except that the same resin as in Example 6 was used and the extrusion temperature and chill roll temperature were the same as in Example 6. Table 1 shows the measurement results of the unrolled sheet for ripening and the obtained molded product.

〔Effect of the invention〕

The laminated container with a rough inner wall of the present invention becomes much more transparent than a normal container with a transparent inner wall due to wetting of the wall surface due to filling with contents, etc., and the contents can be clearly seen from outside the container. Become. As a result, when the container is filled with liquid, sherry, starch syrup, or other contents that are said to be foods or luxury items, there is very little possibility that the product value will be lost.

Further, since the container wall portion other than the filling portion is opaque, the container of the present invention is useful in that it can be easily identified by printing various information on this portion.

Claims (1)

[Claims] (1) In a container made of crystalline thermoplastic resin, in which the inner wall surface is rough and the outer wall surface is smooth, the total haze of the wall is 50% or more, and the internal haze of the wall is 10% or more.
% or less, the container is made of crystalline thermoplastic resin and has a rough inner surface.