JPS5873535A - Plastic 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 plastic container, and more particularly to a glass container with excellent transparency and good ultraviolet light shielding properties.

Traditionally, polyester resins, particularly polyethylene terephthalate, have been used in various applications, such as fibers, films, and molded products containing glass fibers, due to their excellent properties such as chemical resistance, dimensional stability, and mechanical performance. Widely used. In recent years, it has become possible to manufacture transparent containers made of polyester resin due to improvements in molding technology, especially blow molding technology, and containers made of FL and TTF polyethylene terephthalate have excellent transparency, gas permeation resistance, and water vapor permeation resistance. sex.

Because of their excellent hygiene, safety, and mechanical properties, they are widely used as containers for carbonated beverages, cooking oil, sauces, pepper oil, seasonings, medicines, cosmetics, alcoholic beverages, etc.

Conventional containers made of polyester resin have mainly focused on functionality and transparency as storage containers, but when used as containers for edible oil or alcoholic beverages, it is important to prevent deterioration due to ultraviolet rays. It is desired to have a decorative appearance as well as a content preservation function.

Methods of imparting light-shielding properties to polyester containers from outside light include methods of coloring polyester containers with inorganic substances, etc.; methods of making the container composite with opaque materials such as paper; methods of making the container with 9 materials; Methods such as wrapping with a film containing a drug have been used.

However, the method of adding inorganic substances and Ill materials has the drawback that when trying to increase the light blocking property in the ultraviolet region, the light transmittance in the visible region also decreases, resulting in a loss of transparency of the container; The method of wrapping with a film containing an ultraviolet absorber has drawbacks such as complicated container manufacturing and high container manufacturing costs.

The inventor of the present invention conducted extensive research to develop a container that does not have these drawbacks, blocks ultraviolet rays, and has excellent transparency, and as a result, the inventor developed Netsumachi Plastic Tree! l1IK average particle diameter is a
We have discovered that by adding a specific proportion of inorganic inert particles of 1μ or less in size and then stretching and orienting them, it is possible to obtain a plastic container with excellent ultraviolet ray blocking properties and good transparency, and have thus arrived at the present invention. be.

That is, the present invention is a container made of a thermoplastic resin containing inorganic inert particles having an average particle diameter of α1μ or less, and in which at least a portion of the body is stretched in more than one axis, and the container is stretched to the maximum extent. The light transmittance of the part is 700mμ in wavelength.
80 cm or more at a wavelength of 350 mμ, and at most so% at a wavelength of 350 mμ.

The thermoplastic resin referred to in the present invention refers to blow molding.

It is a thermoplastic resin that can be molded into a container by a molding method that involves vacuum forming or stretching under pressure forming force. Table IK shows preferred thermoplastic resins. Among these, those having a light transparency of 80 inches or more are preferable, and polyester resins are particularly preferable because the effects of the present invention are particularly exhibited.

Table 1 2) Measured with A8TM D-1003 Among the thermoplastic resins mentioned above, particularly preferred polyester resins include polyethylene terephthalate, which is obtained by reacting a lower alkyl ester of terephthalic acid with ethylene glycol. However, some of the terephthalic acid components (
Usually less than 20 mole), isophthalic acid.

naphthalene dicarboxylic acid, diphenyl dicarboxylic acid/III
Aromatic dicarboxylic acids such as diphenoxyethane dicarboxylic acid-diphenyl ether dicarboxylic acid, diphenylsulfone dicarboxylic acid, etc.; Alicyclic dicarboxylic acids such as hexahydroteretazalic acid, hexahydroinophthalic acid, etc.; adipic acid, one or more of aliphatic dicarboxylic acids such as sepati/acid, azelaic acid, etc.; p-β-hydroxyethoxyh7benzoic acid; other difunctional carboxylic acids such as oxymonzoic acid such as e-oxycaproic acid, and/or Or, a part of the ethylene glycol component (usually 20 molti or less) can be converted into triethylene glycol, tetramethylene glycol,
Hexamethylene glycol, decamethylene glycol.

Neopentyl glycol, diethylene glycol, triethylene glycol, 1.1-cyclohexane dimethylol, 1.4-cyclohexane dimethylol, 2.2-
Substituted with one or more polyfunctional compounds such as bis(4'-β-hydroxyethoxyphenyl)propane, other glycols such as bis(4'-β-hydroxyethoxyphenyl)sulfonic acid, and functional derivatives thereof; It may be a material that can be polymerized well.

Among such polyester resins, homopolymers of polyethylene terephthalate are most preferred;
Terephthalate has an intrinsic viscosity of a5 or higher, and even α
It is preferable that it is 60 or more. Further, the softening point of polyethylene terephthalate is preferably 220°C to 270°C, for example, 250°C to 265°C.

Examples of the inorganic inert particles to be contained in the thermoplastic resin in the present invention include calcium carbonate, titanium chloride, iron oxide, and silica, with titanium oxide being particularly preferred. In addition, the average particle size of the inorganic inert particles must be less than alμ, and in particular, those less than 104μ are preferably used.If the average particle size is larger than alμ, the container may take on a milky color. ), unfavorable.

The amount of inorganic inert particles added varies depending on the particle size of the particles, but it is preferably less than 15% by weight of αO1, and if it is less than 0.01% by weight, a container with good ultraviolet shielding properties may be used. It is difficult to obtain, and if α exceeds 5% by weight, a cloudy container will be obtained.

The plastic container of the present invention has a light transmittance of the highest oriented part of the body of the container at a wavelength of 70% as measured by a town vision ultraviolet spectrophotometer needle (when the sample thickness is α3"g).
80- or more at 0yp+μ, and wavelength 350
It needs to be 50% or less at tnμ or less.

When the light transmittance is lower than 80 cm at a wavelength of 70 G and μ, the container becomes noticeably cloudy and the appearance of the container is impaired. If the light transmittance is as high as 50 mm at a wavelength of 350 mμ, the contents will be easily altered by ultraviolet rays.
This is not preferable because the content line maintenance performance deteriorates. It is particularly preferable that the light transmittance is less than 10F.

In the present invention, it is necessary to use the above-mentioned fine inorganic particles to form a round shape that simultaneously satisfies the above-mentioned transparency and ultraviolet light shielding properties.

The plastic container of the present invention requires that at least a portion of the body be stretched in at least one axial direction.

Normally, when inorganic particles are added and stretched, the stretched portion becomes cloudy, but the present invention is characterized by less clouding.

Further, such stretching is essential for reducing the thickness and weight of the container and improving its mechanical strength.

In the present invention, any method can be selected for adding the inorganic inert particles. For example, a method in which it is added when polymerizing polyester resin, a master pellet containing a high concentration of inorganic inert particles is separately produced, and the pellet is blended with polyester pellets without inorganic inert particles during molding. There are two methods, such as a method in which inorganic inert particles are sprinkled on polyester pellets without the addition of inorganic inert particles and directly molded. The most preferred method is to add it during polymerization of the polyester resin. If the dispersion of the inorganic inert particles in the polyester resin is particularly poor, not only will the commercial value of the container be significantly impaired, but it will also be difficult to obtain a container with good transparency, so ensure uniform dispersion. is preferable.

Examples of the container of the present invention include a bottle and a container obtained by a molding method involving line drawing. As a method for obtaining these containers, for example, in the case of bottles, conventionally known injection blows, direct blows, biaxially oriented stretching blows, etc. are advantageously used. This will be explained below using an example of polyester resin. In the case of injection blowing, a closed-ended parison is formed by direct injection molding of an inflatable geometric shape, which is then transferred into a bottle mold and then blown and expanded. It is preferable to cool the ljK core mold and injection mold for molding with a refrigerant such as water cooling or air cooling. In addition, when molding a container by direct blowing, first heat-melt and extrude the polyester resin into a pipe shape, then cut the pipe-shaped extrudate to the desired length and cut out the bottom to create a bottomed container. The wrinkled parison is then transferred to a gold MIK having the shape of a desired container, and a compressed fluid such as compressed air is blown into the parison to expand it to the shape of the container. When molding a container by direct blowing using polyethylene terephthalate as the polyester resin, a so-called drawdown phenomenon tends to occur when extruding a parison. Therefore, it is preferable to sufficiently increase the melt viscosity of the polymer, and for this purpose, it is preferable to use a polyester resin with a high degree of polymerization, such as polyethylene terephthalate having an intrinsic viscosity of α8 or more, more preferably α9 or more.

When molding a raw container, first use injection molding aK2.
40~300″ OK heat-melted polyester resin,
A parison with a bottom is formed by injection into a preform mold and cooling, and then the parison is reheated to a temperature above the glass transition point of the polyester resin and placed in a metal container having the desired shape of the container. After the transfer, it is axially stretched (by means of a stretching rod) and the compressed fluid, such as compressed air, is softened and expanded to the shape of the container. When the bottomed parison is stretched or expanded by blowing, the stretching ratio of the body of the container is preferably 4 times or more, more preferably 8 times or more in terms of one area ratio.

In addition, methods such as pressure forming and vacuum forming are commonly used as methods for obtaining containers such as pots.

When molding the container of the present invention, a dye is added to the thermoplastic resin.
There is no problem in adding other additives such as IM, fluorescent coloring agents, stabilizers, etc. within a range that does not impair the purpose of the present invention.

The plastic container thus obtained has good transparency and UV-blocking properties, and is useful as a container for 1+% I'* edible oil and alcoholic beverages.

The present invention will be described in detail below with reference to Examples, but the present invention is not limited to the following Examples without departing from the gist thereof. The methods for measuring the main characteristics measured in the examples are shown below.

Intrinsic viscosity: Measured at 35°C using 0-chlorophenol as a solvent.

Light transmittance double visible ultraviolet spectrophotometer (MPS manufactured by Shimadzu Corporation)
-5000 model).

Examples 1 to 8 and Comparative Examples 1 to 7 Injection molding using a pellet of polyethylene terephthalate with an intrinsic viscosity of 1175 to which the inorganic inert particles shown in Table IK were added in the amount shown in Table 1. L7, cylinder temperature 280 ° C. Using a machine, the weight is 50Ll.

A cylindrical bottomed parinone with a length of 175% and a wall thickness of 35% was molded. At this time, the preform mold is immersed in cold water at 3710°C.
It was cooling down. Then, the parino/ is heated to an internal temperature of 9o~
After reheating to ios° C., two-wheel stretch blowing was performed to obtain a bottle with an internal volume of 1/265% in height, a body diameter of 70 to 80%, and an average wall thickness of a30%. Table IK shows the appearance of the obtained bottle and the evaluation results of the light transmittance and haze value of the bottle body.

1 Tokisho 58-73535 (5) According to Table 1, if the particle size of the inorganic inert particles is α1μ or less,
It can be seen that a plastic container with good transparency, To9, and good UV blocking properties can be obtained.

2

Claims (1)

[Scope of Claims] 1. A container made of thermoplastic resin containing inorganic inert particles with an average particle size of 0.1 μ or less], in which at least a part of the body is stretched in more than one axis, The highest KN, the light transmittance of the stretched part is 8 at a wavelength of 700 mμ
0q6 or more and so at a wavelength of 350 mμ
A plastic container characterized in that it is less than or equal to s. 2. The plastic container according to claim 1, wherein the inorganic inert particles are Ti01. 1. The plastic container according to claim 1, wherein the thermoplastic resin is a polyester resin.