JPH01210442A - Linear low-density polyethylene resin composition for medical container - Google Patents

Abstract

PURPOSE:To obtain the title composition which little corrodes a molding machine or a mold during blow molding, can prevent the generation of static electricity on a parison and is decreased in bleeding into the contents during heat sterilization, by adding a specified amorphous aluminosilicate to a linear low-density PE. CONSTITUTION:100 pts.wt. linear low-density PE of a density of 0.900-0.960 and an MI of 0.1-10g/10min, obtained by copolymerizing ethylene with 0.2-20mol% 3-10C alpha-olefin (e.g., propylene) is mixed with 0.001-0.2 pt.wt. zeolite of the formula (wherein M is Na or a monovalent or polyvalent metal equivalent thereto, X is 1.5-2.0, and Y is 0-10), having a mean particle diameter of 0.5-5mum and/or amorphous aluminosilicate possessing the basic particle form of zeolite, obtained by treating said zeolite with an acid.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a linear low-density polyethylene resin composition for medical containers. More specifically, the present invention is suitable for use as a base material for medical containers, especially infusion containers, and has extremely low corrosion of the molding machine and mold during blow molding, and prevents the generation of static electricity on the parison. The present invention relates to a linear low-density polyethylene resin composition for medical containers that has excellent features such as being able to provide medical containers that do not elute into internal contents during heat sterilization.

[Prior Art] Conventionally, soft vinyl chloride resin has generally been used for medical containers such as infusion containers. However, although products made of soft vinyl chloride resin have excellent performance such as processability, mechanical strength, transparency, and cold resistance, they do not contain additives, especially plasticizers, etc. contained in the resin composition. However, it has had the disadvantage that it may elute into the internal contents of the container, impairing its safety for living organisms. Therefore, the use of various visible synthetic resins is being considered as an alternative to such medical containers made of soft vinyl chloride resin.
Among these, attempts have been made to use polyolefin resins, which are highly safe, have excellent physical properties, and are inexpensive.

By the way, linear low-density polyethylene has lower manufacturing and labor costs than conventional low-density polyethylene, and
Due to its excellent mechanical properties such as rigidity, impact strength, and stress crack resistance, as well as heat resistance and cold resistance, it has attracted particular attention in recent years, and its use has been attempted in various fields.

Such linear low-density polyethylene is also seen as a promising base material for medical containers such as infusion containers, but linear low-density polyethylene usually contains halogens caused by catalysts used during manufacturing. Because it contains chemical compounds, if you try to blow mold it directly to make medical containers, you will inevitably suffer metal corrosion in the blow molding machine, mold, etc. Therefore, attempts have been made heretofore to add halogen scavengers, such as hydrotalcite (Japanese Unexamined Patent Publication No. 52-49258), metal soaps, etc., to the linear low-density polyethylene to exhibit a rust-preventing effect.

However, the method of adding hydrotalcite is
Although it exhibits a certain degree of rust prevention effect, it has the drawback that static electricity is generated significantly in the parison during blow molding, making continuous molding difficult.

I: The method of adding metal soap also exhibits a rust prevention effect, but when the molded container is heat sterilized,
There is a problem that the metal soap may be eluted into the contents of the container.

[Problems to be Solved by the Invention] Under these circumstances, the present invention provides a method that minimizes corrosion of the molding machine and mold during blow molding and prevents the generation of static electricity on the parison. The purpose of this invention is to provide a linear low-density polyethylene resin composition for medical containers that has excellent characteristics, such as being able to provide medical containers that do not elute into internal contents during heat sterilization. It is.

[Means for Solving the Problems] The present inventors have conducted intensive research to develop a linear low-density polyethylene resin composition for medical containers having the above-mentioned excellent characteristics. It was discovered that a material containing a specific ratio of zeolite or a specific aluminosilicate as a halogen scavenger to density polyethylene is suitable for the purpose, and based on this knowledge, the present invention was completed. .

That is, the present invention provides (A) 100 parts by weight of linear low-density polyethylene, (B) zeolite and/or an amorphous aluminosilicate having the basic particle form of zeolite obtained by acid-treating the zeolite. 0.001~0.
The present invention provides a linear low-density polyethylene resin composition for medical containers, which contains 2 parts by weight of the present invention.

The present invention will be explained in detail below.

In the composition of the present invention, the linear low density polyethylene used as component (A) contains ethylene and preferably 0.2 to 20 mol%, more preferably 1 to 10 mol% of carbon atoms having 3 to 10 carbon atoms. Examples include those obtained by copolymerizing at least one a-olefin in a liquid phase or a gas phase.

Examples of the a-olefin include propylene, butene-11pentene-11hexene-11butene-1,
Examples include octene-11nonene-11decene-1,4-methylpentene-1,4-methylhexene-1,4,4-dimethylpentene-1. Such linear low density polyethylene has a density of 0.900 to 0.9.
60g/cm3, preferably 0.910-0.9259
/ cm3, and the melt index (M
I) is 0.1 to lOgZlO, preferably 0.5
A range of ˜4.0 g/10 minutes is suitable.

Ordinary low-density polyethylene has inferior heat resistance compared to the linear low-density polyethylene described above, so if this material is used as a base material for medical containers, the containers may be damaged during heat sterilization. There is a risk of Further, if desired, high-pressure low density polyethylene or high density polyethylene may be blended in the linear low density polyethylene in a range of 0.1 to 40% by weight.

In the composition of the present invention, as component (B), zeolite and/or an amorphous aluminosilicate having the basic particle form of zeolite obtained by acid treatment of zeolite is used. The former zeolite has the general formula % (M in the formula is Na or a monovalent or polyvalent metal equivalent thereto, X is a number from 1.5 to 2,0, and y is a number from 0 to 10). It is an aluminosilicate with a unique crystal structure that can be identified by expressed chemical composition and X-ray diffraction,
It may be a natural product or a synthetic product.

Examples of such zeolites include A-type zeolite, P-type zeolite, X-type zeolite, Y-type zeolite,
Examples include sodalite, analcyme, etc.
These may be used alone or in combination of two or more. In the present invention, among these zeolites, A-type zeolite and X-type zeolite, which are nearly spherical, are preferred, and A! zeolite is particularly preferred from an industrial standpoint. Zeolites are preferred.

The A-type zeolite is a crystalline aluminosilicate represented by the general formula % (in which M is an alkali metal or alkaline earth metal, and n is the valence of M), and is a cation-exchangeable zeolite. It has a crystal structure belonging to an equiaxed crystal system. Examples of A-type zeolite include sodium A-type zeolite, potassium Am zeolite, calcium A-type zeolite, magnesium A-type zeolite, etc., and these may be used alone or in combination of two or more. Alternatively, these cations may be mixed in the same crystal.

On the other hand, as the latter amorphous aluminosilicate, one having the basic particle form of zeolite obtained by acid treatment of zeolite is used. Although this material has the basic particle shape and particle size distribution of zeolite, it is amorphous and does not have a crystalline structure like zeolite.

Such amorphous aluminosilicate is obtained by acid-treating zeolite. The acid treatment is performed, for example, by adding an acid or an acidic substance such as sulfuric acid or phosphoric acid to an aqueous slurry of zeolite to adjust the pH to 4.5 to 9, preferably 5.
This is done by adjusting the acidity to a weak acidity of ~7. This p
When l( is less than 4.5, the basic particle morphology such as the particle shape and particle size distribution state of the zeolite changes significantly, or the entire particle dissolves, which is undesirable. When the pH exceeds 9, it is difficult to become amorphous. So I don't like it.

This amorphous aluminosilicate is usually of the Na type, and although the cation exchange ability characteristic of zeolites has virtually disappeared, the slight remaining cation exchange ability allows Na+ to be exchanged with other cations. , for example (a++, Mg
++, Ba'', zn++, pb++, etc. It is also possible to perform coating treatment with metal hydroxides such as aluminum, titanium, zirconium, antimony, amorphous silica, etc.

The amorphous aluminosilicate referred to here includes not only those in which no diffraction lines are observed in the X-ray diffraction diagram, but also
It also includes those in which the height of the diffraction line is reduced to less than half that of zeolite and is substantially amorphous.

In addition, the zeolite that is the raw material for the amorphous aluminosilicate may be a natural product or a synthetic product, but the zeolite has a S r 02 / A Q z Oi molar ratio of 5 or less, particularly 4 or less. This is preferable because its unique crystal structure is easily decomposed by acid treatment. Examples of such zeolites include A-type zeolite, P-type zeolite, X-type zeolite, Y-type zeolite, etc., and these may be used alone or in combination of two or more types. Among these, it is particularly preferable to use type A zeolite and type X zeolite, which are nearly spherical.

In the present invention, the zeolite and amorphous aluminosilicate as component (B) have an average particle diameter of 0.5 to 577.
m, especially 1.5 to 3.5. It is preferable that the particle size is in the range of 0.5 to 1.5 times the average particle size, and that the particle size distribution of the particles is 50% or more of the total particle size. In addition, this CB) component has a spherical or rounded cubic particle shape,
It is also preferable that the particle surface is smooth.

In the composition of the present invention, the amount of the component CB) added is as follows:
0.001 to 0.2 parts by weight, preferably O,
The amount is selected within the range of 0.01 to 0.1 parts by weight. This addition amount is 0
．． If it is less than 0.001 part by weight, the object of the present invention cannot be fully achieved, and if it exceeds 0.10 part by weight, static electricity will be generated significantly on the parison during tallow molding, and continuous moldability will tend to deteriorate.

If desired, antistatic agents, phenolic or phosphorus antioxidants, ultraviolet absorbers, heat stabilizers, etc. can be added to the composition of the present invention, but it is not preferable to add substances that tend to bleed.

The composition of the present invention can be prepared by conventional methods. For example, the above (A) and (B) components and the various additives as desired may be kneaded using a kneading machine such as a Nigu or Banbury mixer, a single-screw or twin-screw mill, etc. can do. Furthermore, as a method for manufacturing medical containers using the composition of the present invention as a base material, a blow molding method conventionally used for manufacturing containers can be applied. For example, when manufacturing an infusion container as the medical container, the linear low-density polyethylene resin composition of the present invention is blow molded to integrally form an opening, a shoulder, and a body in a predetermined shape. Then, by welding the side and lower periphery of the body inwardly using impulse sealing or heat sealing, the area near the periphery of the body can be easily crushed due to the pressure difference between the inside and outside of the body. It is possible to manufacture a liquid infusion container that is moist.

The resin composition of the present invention hardly corrodes the molding machine or mold during such blow molding, and
There is also very little static electricity generated on the parison. Furthermore, when the obtained container is subjected to heat sterilization treatment, there is no elution into the internal contents, and there is no damage to the container.

[Effects of the Invention] The linear low-density polyethylene resin composition for medical containers of the present invention is made by adding zeolite and a specific amorphous aluminosilicate to linear low-density polyethylene, and during blow molding, It has excellent features such as extremely little corrosion of the molding machine and mold, the ability to prevent the generation of static electricity on the parison, and the ability to provide medical containers that do not elute into internal contents during heat sterilization. It is particularly suitable for use as a base material for containers for infusions.

[Example] Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited in any way by these examples.

In addition, each physical property of the composition was evaluated according to the following method.

(1) Corrosiveness It was evaluated using the press corrosion test method.

That is, on a piece of metal consisting of 5IOC carbon steel, 250
℃ and 5 kg/cm" for 30 minutes to prepare a test piece. After humidifying this test piece for 5 days, the hue of the metal piece (Hunter color coordinates, a″ value) was evaluated using a color computer manufactured by Suga Test Instruments Co., Ltd. The larger a″ is, the higher the corrosivity is.

(2) Static electricity generation rate The degree of static electricity generation in the parison was determined by the ash flying method.

That is, resin temperature 160℃, discharge amount 5 kg/h
The molding was carried out under the molding conditions of r, and the degree of static electricity generation was quantified based on the longest distance until the ash adhered to the parison.

(3) Place 20 g of the eluable resin composition pellets in a suitable hard glass container, wash thoroughly with 0.45 μm filtered water, and add 200 m of physiological saline solution (1) filtered through a 0.45 μm filter. In addition, the mixture was sterilized at 110°C for 40 minutes, and then cooled; thereafter, the number of particles of 2 μm or more was measured using a Coulter counter to evaluate dissolution properties.

In addition, the following were used as the linear low density polyethylene and the halogen scavenger.

Linear low density polyethylene (1) LL-I: MI = 2.09/10 min, density =
0.91527 cm", α-olefin-octene-1 (2) LL-n: MI = 2.09710 min, density =
0.915 g/cm3, α-olefin nibten-1 (3) LL-I[[:MI = 1.3 g/l 0 min,
Density = 0.915 g7cm", a-olefin-octene-1 Halogen scavenger (1) Zilton M (manufactured by Mizusawa Chemical Industry Co., Ltd.) M9-A type zeolite, average particle size 2.0 μm 1 average particle size 0.
90% content of particles having a diameter in the range of 5 to 1.5 times , average particle size 2.0 μm 1 average particle size 0.5
80% content of particles with a diameter in the range of ~1.5 times (3) Karste S (manufactured by NOF Corporation) metal soap (
Calcium stearate) (4) DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.) Hydrotalcite Examples 1 to 11. Comparative Examples 1 to 9 Resin compositions shown in Table 1 were prepared with or without the addition of various halogen scavengers to 100 parts by weight of various linear low-density polyethylenes, and their physical properties were evaluated. The results are shown in the table.

(Margin below)

Claims (1)

[Claims] 1 (A) 100 parts by weight of linear low density polyethylene, (B) zeolite and/or amorphous aluminosilicate having the basic particle form of zeolite obtained by acid treatment of zeolite 0.001 to 0 .2 parts by weight of a linear low-density polyethylene resin composition for medical containers.