JPS60125625A - Blow molding method - Google Patents

Abstract

PURPOSE:To form a thickness of a part forming an air blowing port thickly and unitarily and to obtain further the air blow port which is beautiful with large strength, by making molding by arranging a blow nozzle on a portion whose part is cut open and both ends of the part become thick. CONSTITUTION:An air blow port, whose thickness of a parison at a part 10 corresponding to an air blow port is thicker as compared with the other part, to be formed by a blow nozzle 7 and a mold by a method wherein molds 4a, 4b having predetermined mold surfaces are confronted with each other, between which a parison 5 whose part is cut open and both end parts of the part are made thicker than the other part is hung down, clamping of the molds 4a, 4b is performed by making a blow nozzle 11 position between the end parts 8, the end parts 8 of the parison 5 are abutted against the part 10 corresponding to the air blow port, and the end parts 8 are abutted against positions in the vicinity of the blow nozzle 7 being filled with the parison. Then a shape of the mold surface formed by making a pressure fluid inject within the parison from the blow nozzle 7. Then a bag body 1 formed by the titled blow molding method can be taken out by pulling out the blow nozzle 7 and opening the molds 4a, 4b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a blow molding method that can partially provide thick-walled parts, and more specifically, parylan is partially cut open, and the cut-out part is made into a thick wall near the blowing nozzle. This is a blow molding method characterized by increasing the wall thickness.

BACKGROUND ART Elastic air bladders such as seat lumbar supports or blood pressure measurement bags have conventionally been made of rubber. However, since rubber molding requires a vulcanization process, productivity is very low and production time is long, resulting in expensive products. Therefore, bags are now being made of thermoplastic elastomers, which are highly productive and do not require a vulcanization process. There are two ways to mold the thermoplastic elastomer that is the material of this bag: a method of forming a sheet and high-frequency welding, and a method of blow molding. Since the elasticity of the thermoplastic elastomer used is significantly lower than that of rubber, rubber cannot be used as a substitute. On the other hand, with blow molding, it is possible to mass-produce products equivalent to those made of rubber. , connecting parts, protruding parts, etc. cannot be integrally molded, and for example, when an air supply pipe made of another member such as a rubber pipe must be connected to a bag formed by blow molding, this connection is This was accomplished by pushing a rubber tube into the air inlet of the bag and gluing it or by high-frequency welding. This kind of secondary processing is
The work itself was very complicated, and the adhesive often oozed out and the welded parts were thermally deformed and deteriorated, making it unsuitable for commercial use.

The present invention was invented in view of this point, and its purpose is to thicken the wall thickness of the part that forms the air inlet so that it can be integrally formed during molding, and also to have a beautiful appearance. The strength is also to obtain a large air inlet.

The case where the present invention is used in a blood pressure measuring bag will be explained below with reference to the drawings. FIG. 1 is a perspective view of a blood pressure measuring bag 1 obtained according to the present invention. 2 is a main body, and 3 is an air inlet for introducing pressure into the main body. This air inlet 3 is
It is thicker than the main body 2.

Next, the blow molding method of the present invention will be explained based on the drawings. First, a mold 4a having the external shape of the desired bag 1 on its mold surface is made.
, 4b are spaced apart from each other. The molds 4a are spaced apart from each other,
4b, a part is cut open, and the cut-out end part 8 hangs down the parillan 5, which has a thicker wall thickness than the other part. The blowing nozzle is placed in the parillan 5 so as to be located between the cut-out ends 8.

In order to extrude this paris 5, the shape near the exit of the resin path formed by the die 6 and the core (not shown) is made into a shape similar to the cross-sectional shape of the paris 5 shown in FIG. It is formed by The reason why I said "similar" here is that when a synthetic resin exits from the inside of the die 6 to the outside, it tends to change its shape inward or outward due to the pressure difference at that time or the 5heer rate (shear rate). This is because the resin path within the die must be designed taking these values into consideration. Generally, thermoplastic bolastomers are extruded at a small 5heer rate to ensure molding without defective molding, so Parylan is relatively similar to the shape of the resin outlet. Mold clamping is started when the hanging of Parirun 5 reaches the lower part of the mold.

As the mold clamping progresses, the molds 4a and 4b come into contact with the Parylan 5, and as the mold clamping progresses further, the cut-out end B8 of the Parylan 5 comes into contact with the part 10 corresponding to the air injection port on the mold surface, as shown in FIG.
The end portion 8 corresponds to the vicinity of the blowing nozzle 7, and the wall thickness of the air inlet corresponding portion 10 is thicker than other portions, and the air inlet formed by the blowing nozzle 7 and the mold is The entrance is filled with parillans. Next, pressure fluid is jetted into the parison from the blowing nozzle 7, and the parillon is brought into contact with the cavity surface 9, thereby shaping the shape of the mold surface. After the cooling time has elapsed, the ejection of the pressure fluid is stopped, the blow nozzle 7 is pulled out, the molds 4a and 4b are opened, and the bag body 1 is taken out, and the present blow molding method is completed.

In this example, the shape of the Parylan was basically a circular Parylan with a part cut out (so-called circular die extrusion), but the shape is not limited to this. The present invention can also be applied to sheet-like Parylan. Even in such a case, Parylan is attached to one end (or both ends).
The present invention is carried out by extruding the Parylan with a thick wall and hanging it down so that the air inlet is located at that part.

The idea of making the air inlet thick in the bag of the present invention is as follows:
It can be used not only for the air inlet of a blood pressure measuring bag, but also for the mouth of a water pillow or the mouth of an infusion bottle. In blow molding, since Parylan is inflated and molded, it is not possible to make only one part thick, and in particular, as in the blood pressure measuring bag of the embodiment of the present invention, the air pressure is low and the bag is inflated isobarically. In a product for which this is desired, the material of the main body itself must be elastic and thin, whereas the air inlet must be thick.

In the present invention, any synthetic resin material that can be blow molded can be used. In addition, in order to manufacture an elastically moldable bag as in the example, soft polyvinyl chloride or polyester elastomer is used.

Materials such as polyurethane elastomer, polyamide elastomer, olefin elastomer, and styrene elastomer can be used. The soft polyvinyl chloride has an average degree of polymerization of 800 to 12,000, preferably 1.5.
00 to io, o 00 polyvinyl chloride, and 30 to 220 parts by weight based on 100 parts by weight of the polyvinyl chloride,
Preferably, it is blended in an amount of 50 to 200 parts by weight. ”- If the average degree of polymerization of the polyvinyl chloride is less than 800, mechanical strength such as tensile strength decreases, while 12.00
If it exceeds 0, the surface appearance of Parylan during molding will be poor and the moldability will be extremely poor. Furthermore, if the amount of the presentable agent added to the polyvinyl chloride is less than 30 parts by weight, the molded product will become inelastic, while if it exceeds 220 parts by weight, mechanical strength such as tensile strength will be significantly reduced. Various other fillers, stabilizers, stabilizing aids, pigments, etc. can also be appropriately blended into the above-mentioned soft polyvinyl chloride.

FIG. 5 shows a lumbar support for an automobile manufactured according to another embodiment in which the thick end of the pari run is provided at the other parting line. The lumbar support 21 includes a main body 22, an air inlet 23, and a bracket 24. The bracket 24 is obtained by compressing the thick end portion of Parylan with a mold. The bracket has a mounting hole 25.

In this way, a plurality of air inlets may be provided, and the thick end portions may also be provided at both ends on the parting line.

As described above, the present invention extrudes a Parylan which is partially cut open and has thick walls at both cut ends, closes the mold by arranging the blow nozzle between the two ends, and closes the mold by disposing the blow nozzle. This is a hollow molding method characterized by compressing a thick parylan with a mold and a mold to form a thick part on the parting line of the hollow body. The wall itself is made thin and elastically deformable, and the parts that are attached to this main body, such as the blood pressure measurement bag, the air inlet of a car's Lampasaport, and the mouth of a water pillow.

Adjust the wall thickness of the infusion bottle stopper fitting mouth part etc. to the desired thickness 1
．． Reinforcement body for air injection pipe and water container respectively.

This allows for easy insertion of plugs, etc. In addition, since the present invention is integrally molded during molding, there is no adhesive extrusion as in adhesive bonding, deterioration or deformation of parts as in high frequency welding, and a beautiful appearance can be obtained. There is no risk of liquid leakage or air leakage.

[Brief explanation of drawings]

FIG. 1 is an overall perspective view of a blood pressure measurement bag obtained according to an embodiment of the present invention, FIG. 2 is an overall perspective view showing the method of the present invention, and FIG. 3 is a cross-sectional view of FIG. 2. . FIG. 4 is a cross-sectional view showing the state during mold clamping progress, and FIG. 5 is an overall perspective view of the lumbar support obtained by the present invention. 1 Bag body 3 Air injection ports 4a, 4b Mold 8 Thick wall portion Patent applicant: Kyoraku Co., Ltd. :) Figure 4 Figure 5 Figure 2

Claims (1)

[Claims] Parylan, which has been partially cut open and has a thick wall at both cut ends, is extruded, a blow nozzle is placed between the two ends, the mold is closed, and the thick wall is formed by the blow nozzle and the mold. A blow molding method characterized by compressing Parylan to form a thick part on the parting line of the hollow body.