JPS6157178B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to polyethylene, polyvinyl chloride,
This relates to a method for manufacturing tubular molded products made of synthetic resins such as polypropylene and polyamide.
This invention relates to an improved invention of No. 958504 (see Japanese Patent Publication No. 53-31181).

The above-mentioned patent No. 958504 uses a cooling device installed above a die installed at the extrusion port of an extruder in the inflation method, and a horizontal annular shaft installed at the outer periphery of the tube to be extruded has an uneven pattern of an arbitrary shape on the outer periphery. A engraved disk-shaped rotary mold is provided so that it can be freely rotated several times as needed, and the protrusions on the outer periphery of these rotary molds are brought into contact with the outer periphery of the tube in front of the front line, so that the portion of the tube that the above-mentioned protrusion comes into contact with is suddenly After cooling and solidifying, the non-contacting portions are stretched, the cooling and solidifying portions are thicker, and the stretched portions are thinner, so that both the inner and outer surfaces of the tube, or one of these sides, are formed with a convex shape corresponding to the shape of the rotary mold. , a synthetic resin tube-shaped molded product having a convex pattern A as shown in FIG. 2 is manufactured. However, this is because the rotary mold is fixed so that it rotates parallel to the direction in which the resin flows out from the die, so the convex pattern on the finished tube is continuous and parallel to the direction in which the resin is extruded from the die. It will be done. Therefore, the arrangement of the molecules in the convex pattern A and the non-convex part C of the completed tube are parallel, and the boundary between the convex pattern A and the non-convex part C deteriorates significantly. Therefore, this tube had the disadvantage of being susceptible to vertical tearing.

The purpose of this invention is to manufacture a synthetic resin tube-shaped molded product that eliminates these drawbacks, and involves moving the rotary mold along the outer periphery of the tube and bringing the convex portion of the rotary mold into contact with the outer periphery of the tube. The tube produced by this method has a continuous convex pattern that crosses the direction in which the tube or synthetic resin flows out from the die, and the longitudinal tearing strength of the tube is extremely strong. Furthermore, when the tube is folded flat, the convex patterns on both inner surfaces do not overlap in parallel, and when it is made into a bag or the like, it has various advantages such as an extremely good opening. Further, in the above manufacturing method, tubes with various convex patterns can be easily manufactured by appropriately changing the moving direction and speed of the rotary mold or the extrusion speed of the tube.

Embodiments of the present invention will be described below with reference to the drawings.
First, the apparatus used in this invention will be described. 1 is an extruder, 2 is a die provided at the extrusion port of the extruder 1, and is used to form a synthetic resin into a tube shape. 3 is an air hole provided in the center of the die 2; 4 and 5 are annular primary and secondary cooling devices provided above the die 2 with an interval; Air blows out from the edges toward the center. Reference numeral 6 denotes an annular rotary mold assembly provided between the cooling devices 4 and 5, and this rotary mold assembly 6 is mounted on the bottom plate of an annular support plate 7 having a key-shaped cross section via a bearing 8 into a first annular mold assembly. A plate 9 is rotatably provided, and a second annular plate 11 is rotatably provided on the first annular plate 9 via a bearing 10.
An appropriate number of protruding rods 1 from the inner peripheral edge to the center of each
A suitable number of rotating molds 13 are rotatably provided at the tips of the respective protruding rods 12, and a friction roller 16 fixed to the tip of the rotating shaft 15 of the motor 14 is connected to the upper surface of the first annular plate 9 and the second annular plate 9. This is brought into contact with the lower surface of the annular plate 11. In addition, the rotary mold 13 is shown in FIG. 4A,
As shown in B and C, appropriately shaped protrusions 13a and recesses 13b are provided on the outer peripheral surface of the disc-shaped body.
17 is a stabilizer plate provided above the secondary cooling device 5 in a V-shape, and 18 is a pinch roller provided above this stabilizer plate 17.

Next, the manufacturing method of this invention will be explained.
The synthetic resin kneaded and melted in extruder 1 is transferred to die 2.
A more gel-like tube 19 is formed and continuously extruded, air is sent through the air hole 3 provided in the center of the die 2, the gel-like tube 19 expands, and is cooled by the primary cooling device 4. Ru. On the other hand, when the motor 14 is driven, the first annular plate 9 and the second annular plate 11 rotate in opposite directions due to the rotation of the friction roller 16. When the tube 19 reaches the inside of the rotary mold assembly 6, first the outer circumferential convex portion 13a of the rotary mold 13 of the first annular plate 9 is inserted into the tube 1.
It contacts the outer peripheral surface of 9. As a result, the portion of the outer circumferential surface of the tube 19 that is in contact with the tube 19 is rapidly cooled and solidified. At this time, since the outer periphery of the rotary mold 13 is engraved with an uneven pattern, the outer periphery of the tube 19 has a convex portion 1.
3a and not the recess 13b.
The outer circumferential surface of the tube 19 in contact with the convex portion 13a is deprived of heat and increases in viscosity, and as the tube 19 moves upward due to the tension of the pinch roller 18, the rotary mold 13 rotates and comes into contact with the convex portion 13a. Since the outer peripheral surface of the tube 19 is cooled and solidified, it is easily separated from the outer peripheral surface of the rotary mold 13. The outer circumferential surface of the tube 19 in contact with the convex portion 13a of the rotary mold 13 is deprived of heat by the rotary mold 13, increases in viscosity, and rapidly solidifies. However, the portions of the outer circumferential surface that do not come into contact with the convex portions 13a are not individualized and are stretched to a large extent and become thinner. In this way, the tube 19 passes through an appropriate number of rotary molds 13 of the first annular plate 9, but the first annular plate 9 rotates in one direction, and the tube 19 always moves upward. Therefore, the locus of the outer periphery of the tube 19 that comes into contact with the convex portion 13a is formed in a spiral shape. Further, an appropriate number of rotary molds 1 of the second annular plate 11
3. Pass through the inner circumference in the same manner as above. Since this second annular plate 11 is rotating in the opposite direction to the first annular plate 9, the locus of the outer circumferential portion of the tube 19 that has contacted the convex portion 13a on the outer circumference of the rotary mold 13 is different from that of the first annular plate 9. spiral in the opposite direction. In this state, the tube 19 is further moved upward, and the secondary cooling device 5
At this point, the outer circumferential surface of the tube 19 is further cooled and solidified, but the inner circumferential surface of the tube 19 is not yet solidified and is further expanded or stretched. This allows tube 1
The portion of the rotary mold 13 in contact with the convex portion 13a of No. 9 forms a highly transparent convex pattern 20 due to rapid solidification, and the portion that does not contact the convex portion 13a of the rotary mold 13 stretches and becomes stripped. The tube 19 stretched in this manner is folded flat by the pinch rollers 18 through the stabilizer plate 17, and then wound up.

The present invention is the above manufacturing method, and the tube 19 produced by this method has a spiral convex pattern 20 crossing the inner and outer surfaces of the tube 19 as shown in FIG.
is formed, and this convex pattern 20 is formed on the substrate with increasing thickness. This intersecting spiral convex pattern 20 crosses over the unidirectional spiral convex pattern 20 formed by the rotary mold 13 of the first annular plate 9, A spiral convex pattern 20 in opposite directions is formed by the mold 13. That is, the portion of the outer peripheral surface of the tube 19 that is in contact with the outer peripheral convex portion 13a of the rotary mold 13 of the first annular plate 9 is cooled and solidified, but is still stretched to some extent. However, when the convex portion 13a on the outer periphery of the rotary mold 13 of the second annular plate 9 comes into contact with this area, it is further cooled and solidified, so that only that area maintains almost the same thickness. Therefore, the intersecting portions of the convex patterns 20 are thicker than the convex patterns 20 at the outer circumferential portions of the tubes 19 that are in contact only with the outer circumferential convex portions 13a of the rotary mold 13 of the first annular plate 9. Therefore, the spiral convex pattern 20 of the finished tube 19 is thicker than the base of the tube 19, and furthermore, the intersection part of the spiral convex pattern 20 is thicker than the pattern 20 part. As described above, according to the present invention, the finished tube 19 has a continuous convex pattern 20 that intersects the direction in which the pinch roller 18 flows out from the die 2, so that the openings at both ends of the tube are directed upward and downward. Even when a horizontal force is applied to the tube, it does not tear easily and has extremely high strength against longitudinal tearing. This is because materials with high crystallinity, such as medium-high density polyethylene, polypropylene, and nylon, have high strength when placed vertically in the direction of resin flow, but tear when subjected to horizontal forces. In the case of materials that are easy to use, these drawbacks are eliminated as described above, and the effect is particularly great. Furthermore, the inner surface of the tube 19 completed as described above also has an intersecting spiral convex pattern 20, and the intersecting portion is thicker than the other convex patterns 20, so that the concave and convex portions are formed even larger. When the bag 19 is folded flat to form a bag or the like, the sheets on both sides of the bag do not come into close contact with each other, and the bag has the advantage of having a good opening.

Note that the one shown in FIG. 6A has a fourth rotary mold 13.
As shown in Figures A or B, a continuous outer periphery protrusion 13a is used, and in the case of Fig. 6B, the outer periphery protrusion 13a has a continuous interval between the outer periphery protrusions 13a in the rotary mold 13 as in the case of Fig. 4C. This is the case when using a warmed one.

Furthermore, if the motor 14 is reversed at regular intervals instead of the above embodiment, the rotation of the first annular plate 9 and the fifth annular plate 11 will be reversed at regular intervals, so that the completed tube As shown in FIG. 7, a wavy convex pattern 20 intersecting the flow direction of the resin in the tube is formed on the inner and outer surfaces of the tube 19, and has the same effect as described above.

Also, instead of the above embodiment, the first annular plate 9 or the second
When the annular plate 11 and the rotary mold 13 attached thereto are removed, the first annular plate 9 or the second annular plate 11
As the tube rotates, a tube 19 is formed as shown in FIG. 8, which has only a spiral convex pattern 20 in one direction on its inner and outer surfaces. In this case, as in the above-mentioned embodiment, the direction in which the resin flows out of the tube 19 intersects with the convex pattern 20, so that when the tube is placed with its openings at both ends up and down, the longitudinal tearing strength is large and it will not easily tear. do not have. Also tube 19
When the bag is folded to form a bag or the like, the convex patterns 20 on both side sheets of the bag form a spiral shape in opposite directions across the folds, so the both side sheets do not come into close contact with each other and have the advantage of a good opening.

Further, in this invention, the spiral convex pattern 2 is formed depending on the extrusion speed of the tube 19 and the moving speed of the rotary mold 13 in the above embodiment.
Tube-shaped molded products having various degrees of zero or wavy inclination can be produced very easily.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, FIG. 1 is a sectional view of a conventional product, FIG. 2 is a front view of a conventional product, FIG. 3 is a partially sectional front view showing the manufacturing method of this invention, and FIG. 4 A, B, and C are respectively a front view and a side view of a rotary mold used in this invention, FIG. 5 is an explanatory diagram showing the manufacturing method of this invention, and FIG. Partial perspective view of tube-shaped molded product, No. 7
The figure is a front view of a tube-shaped molded product made according to another embodiment of the present invention, and FIG. 8 is a perspective view of a tube-shaped molded product made according to still another embodiment of the invention. In the figure, 1 is an extruder, 2 is a die, 6 is a rotating mold assembly, 9 is a first annular plate, 11 is a second annular plate,
13 is a rotary mold, 14 is a motor, 16 is a friction motor, 18 is a pinch roller, 19 is a tube, 20
has a convex pattern.

Claims (1)

[Claims] 1 In the inflation method, a tube is extruded from a die provided at the extrusion port of an extruder, and the outer periphery convex part of a rotatable disc-shaped rotary mold with an irregular pattern of an arbitrary shape engraved on the outer periphery is inserted into the frost of the tube. Synthetic resin tube-shaped, characterized in that the rotary mold is moved along the outer circumference of the tube on a constant plane substantially perpendicular to the tube extrusion direction while being in contact with the outer circumference of the tube in a molten state before the line. Method of manufacturing molded products.