JPH0526395A - Internal pressure container - Google Patents

Abstract

PURPOSE:To obtain an internal pressure container having pressure resistance, low temperature toughness, high temperature dimension stability, chemicals resistance, and moldability by molding into a container or composition formed by blending plastics with a plate-shaped inorganic filler, for example, glass flake. CONSTITUTION:A polyester resin, for example, a PBT (polybutylene terephthralate) resin is the most suitable as plastics blending a plate-shaped inorganic filler. For example, a glass flake 20%-blended PBT resin is injection- molded from a gate at the center of a container bottom part 1 to obtain a molding formed by integrating the bottom part 1 and a barrel part 2. Supersonic wave welding is applied to the molding and a separately molded shoulder part 3 to obtain an internal pressure container. The container in combination with a sealing means, for example, a screw-in or mounting cap system injection nozzle, etc., can be used in an internal pressure condition containing a content such as a drug. or a propellant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal pressure container made of plastics and can be suitably used as, for example, an aerosol container. INDUSTRIAL APPLICABILITY The present invention can be used in industrial fields such as drug supply, packaging containers, and plastics molding.

[0002]

2. Description of the Related Art Relatively small internal pressure containers are widely used as containers for aerosol chemicals, liquids under pressure such as effervescent liquids, and gases. The internal pressure container requires a material that has strength suitable for the usage conditions and is impermeable to the medicine to be filled, and most commonly, a metal such as steel or aluminum is used. Plastics containers are lightweight and suitable for mass production, and have advanced into various fields by taking advantage of the fact that products of various shapes that consumers prefer can be easily manufactured, and products with low internal pressure (eg beer, soft drinks) It has been used for the container of). However, plastics are generally inferior to metals in terms of both strength and impermeability, and some technology was required to realize an internal pressure container used under more severe conditions.

Taking an aerosol container as an example,
The material used for it must be resistant to both chemicals and propellant gases and have chemical resistance. Of course, it is necessary to have pressure resistance according to the operating conditions,
It is also necessary to consider when left at a low temperature. Since it is often handled with one hand, it is also necessary to withstand the impact of accidentally dropping it. JP-A-46-24
Reference numeral 84 is a technique using a specific molding temperature condition.
35166 discloses a technique using a fiber reinforcing agent oriented in a specific direction, and solves the problems in plastic aerosol containers.

[0004]

The present invention takes advantage of the characteristics of plastics that are lightweight and suitable for mass production, and are easy to make irregularly shaped containers. For example, internal pressures satisfying some strict requirements such as aerosol drug containers. It aims to provide effective technology for realizing containers. Required characteristics to be especially considered are pressure resistance, low temperature toughness, high temperature dimensional stability, chemical resistance and formability.
Pressure resistance of 40 to 50 kgf / cm2 in a container of about 0 ml, filling condition of contents, and toughness not to be destroyed by a drop test from -10 ° C, 1.5 m are required. The present invention is an internal pressure container that satisfies these characteristics in a well-balanced manner.

[0005]

This problem is solved by molding a composition in which a plate-like inorganic filler, such as glass flakes, is mixed with plastics into a container. A typical plastic used in the present invention is a polyester resin, and for example, a 20% glass flake-blended PBT resin is injection molded from a gate at the center of the bottom of a container to obtain a molded product in which the bottom and the body are integrated. , This is ultrasonically welded to a separately molded shoulder to obtain an internal pressure container. This container can be used under an internal pressure condition containing contents such as a drug and a propellant in combination with a sealing means such as a screwing or mounting cap type injection nozzle.

The plate-like inorganic filler is a thin and two-dimensionally spread inorganic material, for example, glass flakes or mica flakes, and is contrasted with fibrous fillers such as glass fibers and carbon fibers and granular fillers such as glass beads. be able to. Typical glass flakes have a thickness of a few μm (eg:
4 μm), which is considerably smaller than the typical thickness of glass fiber for filler (eg 13 μm). The particle size distribution of glass flakes is around several tens of μm in a molded product when a typical one with a center of several hundreds of μm is supplied. This is also considerably smaller than the length of the glass fiber filler (about 200 to 400 μm in the molded product). As described above, the plate-like inorganic filler can have a size substantially smaller than that of the fibrous filler. Such a plate-like inorganic filler is preferably surface-treated with a silane-based surface treatment agent or the like in order to improve the adhesion at the interface with the plastic.

The amount of the plate-like inorganic filler with respect to the plastics can be selected so that the compounded composition has a desired strength, for example, the flexural modulus as an index. The greater the amount of the plate-like inorganic filler compounded, the greater the strength, and the strength parallel to the resin flow and the strength perpendicular to the flow of the resin are balanced. This is different from the tendency that in the case of a fibrous filler, the strength in the direction parallel to the resin flow is large, and the strength in the direction perpendicular to it is small and unbalanced (particularly when the compounding amount is large). Do. The plate-like inorganic filler can be added in a relatively large amount to increase the strength in both the parallel and right angles. An example of an appropriate blending amount is 10 to 30%, especially 15 to 20%. The upper and lower limits of the compounding amount depend on strength, permeability, weldability, moldability, etc., and are about 5 to 40%.

The physical properties of the glass flake-blended PBT resin measured by the ASTM method are as follows. Blending amount 10% 20% 30% Tensile strength kgf / cm2 570 560 630 Bending strength kgf / cm2 670 680 1100 Bending elastic modulus kgf / cm2 31800 37900 46700 Izod, notched 2.9 2.8 3.0.

Further, a glass flake-blended PBT resin
The flexural modulus measured on a test piece obtained by forming a 20 mm square, 2 mm thick flat plate and cutting it in the resin flow direction (FD) and in the direction perpendicular to the flow (TD) is as follows. This lack of anisotropy in strength has a favorable effect when used as an internal pressure vessel. Blending amount 10% 20% 30% FD kgf / cm2 31400 36800 42200 TD kgf / cm2 31500 36600 42600.

The most preferable plastics containing the plate-like inorganic filler is a polyester resin such as PBT (polybutylene terephthalate) resin. This resin is particularly suitable for the purpose of the present invention because it has excellent chemical resistance, changes in physical properties due to moisture absorption, small dimensional changes, and good moldability. Examples of other resins include PET (polyethylene terephthalate) resin, polyoxymethylene resin, and polyphenylene sulfide resin. Of course, the plastics to which the plate-like inorganic filler is added in the present invention are not limited to these, and those skilled in the art can appropriately select them in consideration of conditions such as durability against the medicine to be filled. it can.

In the present invention, it is necessary that the plate-shaped inorganic filler is blended in the plastics constituting the internal pressure container, but this does not exclude the blending of fillers of other shapes. If desired, a filler having another shape such as fibrous or granular may be used in combination with the plate-like inorganic filler.

[0012]

Example: Glass flakes having an average particle size of 500 μm were mixed with PB.
Molded product (tank) in which the bottom and the body are integrated by injection molding from a single gate provided at the bottom of the container after mixing with T resin (intrinsic viscosity = 1.0) and pelletizing in advance. To get. A separate injection-molded lid (shoulder + nozzle housing) was ultrasonically welded to a diameter of 44 mm and height of 9 mm.
A cylindrical inner pressure container (Fig. 1) with a volume of 0 mm, a capacity of 80 ml and a wall thickness of 2.5 mm is obtained.

It has been confirmed by a water pressure test that the pressure resistance is 60 kgf / cm 2 or more. The same applies when the same tank is used and PBT resin without glass flake is used for the lid. For comparison, an internal pressure container molded using glass fiber-blended PBT resin was tested and found to be 60 kg.
It can be seen that at f / cm2, radial fracture occurs from the bottom gate, and there is a weak point in the direction perpendicular to the glass fiber orientation along the radial resin flow.

The drop impact strength is determined by filling 70 g of ethylene glycol in a container and letting it fall naturally on a steel plate from a height of 1.5 m to check for breakage. Temperature (0 ° C, -10 °
It was confirmed that it did not crack in either C) or the falling direction (normal, horizontal). In the deformation test, the container is immersed in hot water at 60 ° C for 1 hour, taken out, and then the diameter of the central part of the container is measured. Immediately after taking out, the amount of change in diameter is +0.27
However, after cooling to room temperature, it was less than +0.01 mm, and it was confirmed that there was virtually no deformation. When the roundness was measured at the lower end of the lid, it was 9 μm for the one containing glass flakes, whereas it was a large value of 46 μm for the one containing glass fibers. Good roundness contributes to improving the strength of the welded part, preventing gas leakage from the welded part, and preventing gas leakage from the crimp part of the mounting cap or the screwed part of the injection nozzle.

[0015]

The plate-like inorganic filler can be molded into plastics in a relatively large amount without any problem, and exerts a reinforcing effect without discrimination in both directions parallel and perpendicular to the flow direction of the resin. This achieves the strength required for the internal pressure vessel. The ratio (FD / TD) of the bending elastic modulus in the direction parallel to the flow and the bending elastic modulus in the direction perpendicular to the flow is 30
% Of PBT resin is about 1.8 times, but it is almost the same for glass flake 30% of PBT resin. As a result, the flow that tends to occur when the fibrous filler is mixed and the weak points in the direction at right angles are eliminated, and warpage due to longitudinal and lateral contraction strains is eliminated, and a neat shape as designed can be molded.

[0016]

INDUSTRIAL APPLICABILITY The internal pressure container, which is a plastics molded product containing 5 to 40% of a plate-like inorganic filler, is lightweight, suitable for mass production, and makes use of the characteristics of plastics that are easy to form into various shapes. To realize an internal pressure container that satisfies some strict requirements such as a drug container.
INDUSTRIAL APPLICABILITY The product of the present invention is an internal pressure container satisfying well-balanced characteristics such as pressure resistance, toughness, dimensional accuracy, chemical resistance, gas permeability and moldability, which are properties particularly required as an internal pressure container, and the surface condition of the molded product is smooth. Is good at.

In the product of the present invention, the strength is less affected by the flow direction of the resin, and compared to the internal pressure container which is a fibrous filler-containing plastic molded product, it is easier to form a deformed container, and the gate position is improved. The constraints are also small. For example, even if a gate is provided at the center of the bottom surface, there is no defect that the bottom surface is easily cracked in the radial direction. Of course, a method other than the injection molding method in which the gate is placed at the center of the bottom surface can be used if necessary. For example, the upper part provided with the nozzle housing and the body part may be integrally formed by injection molding from three gates provided on the shoulder part, and the separately formed bottom part may be welded thereto. If the conditions are adjusted, the bottom, body, and top may be integrally formed by blow molding or injection blow molding.

[Brief description of drawings]

FIG. 1 is a side sectional view of an internal pressure container that is an embodiment of the present invention.

[Explanation of symbols]

1 ... Bottom part 2 ... Body part 3 ... Shoulder part 4 ... Nozzle housing

Claims (5)

[Claims] 1. An internal pressure container characterized by being a plastics molded product containing a plate-like inorganic filler. 2. The internal pressure container according to claim 1, which is an aerosol container. 3. The internal pressure container according to claim 1, wherein the plate-like inorganic filler is glass flakes. 4. The internal pressure container according to claim 1, wherein the plastic is a polyester resin. 5. The internal pressure container according to claim 1, further comprising a gate at the center of the bottom of the container.