JPS61189927A - Manufacture of three-dimensional reticulate object made of thermoplastic resin - Google Patents

Abstract

PURPOSE:To produce easily three-dimensional reticulate object having the meshes of a net continuously changed in thickness direction by a method in which thermoplastic resin is extruded from a plurality of extruding holes of a nozzle provided on the tip of an extruder, and while a plurality of extruded fine strings are blown from their upside by cooling air in a shaping device or immediately before said device, are taken-off at specified take-off speed. CONSTITUTION:The nozzle 2 provided on the tip of an extruder 1 has a plurality of the extruding holes 21 of Dmm diameter arranged regularly or irregularly. The envelope outer shape of the extruding holes 21 is formed in such a shape as to be almost similar to the sectional shape of a three dimensional reticulate object to be manufactured. The distance L between said holes is in the range of 2D<=L<=15D. The revolutions of the rotary belt 31 and the rotary roll 32 of a shaping device 3 are made to synchronize with the take-off speed of a take-off unit 5. A coding nozzle 4 is arranged near the rotating roll 32, and a plurality of extruded fine strings are blown from their upside by cooling gas. The take-off speed V of the take-off unit 5 for a plurality of the fine strings to the speed V of the resin extruded freely from the nozzle 2, is in the relation of 0.5VD/L<=v<=4.0VD/L, wherein v<V.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention manufactures a three-dimensional thermoplastic resin network consisting of thermoplastic resin strips with different mesh sizes and densities in the thickness direction. Regarding the method.

[Conventional technology]

Conventionally, a three-dimensional network consisting of thin strips of thermoplastic resin is produced by spinning thin strips of molten resin down from a downward nozzle, bending them meanderingly in a softened state, and fusing the contact areas, and then immediately soaking them with water, etc. A method of solidifying by contacting with a cooling liquid is known (Japanese Patent Publications No. 52-14347, Japanese Patent Publication No. 56-3941, and Japanese Patent Application Laid-Open No. 50-25869).

[Problem that the invention seeks to solve]

However, in the method described in Japanese Patent Publication No. 52-14347, although the part in contact with the drum is smooth and has a slightly higher density than other surfaces, the difference in density in the thickness direction is small, and it is difficult to cool. The use of water requires energy for subsequent drying, which is not economical.

Furthermore, the method described in Japanese Patent Publication No. 56-3941 attempts to complicate the bending of a large number of descending strips by spraying turbulent flow from both surfaces of the strips. Therefore, even if it is possible to change the overall density by changing the spinning speed of the strips, the take-up speed, the temperature of the hot air, etc., it is not possible to obtain a three-dimensional network with different densities in the thickness direction.

Furthermore, in the method described in JP-A-50-25869, the overall density can be changed by moving the conveyor upward and by changing the spinning speed of the strips and the relative speed of the conveyor; The density in the thickness direction cannot be changed.

This invention solves these problems and attempts to manufacture a thermoplastic three-dimensional network with a wide range of uses as cushioning and filter materials in fewer steps using an extrusion molding method, in which the mesh size of the strips differs in the thickness direction. It is something to do.

Means for Solving Problem C] The present invention is for manufacturing a thermoplastic resin three-dimensional network body whose density changes in the thickness direction by an extrusion molding method,
In order to extrude the thermoplastic resin laterally from a nozzle attached to the tip of the extruder, a large number of extrusion holes are arranged in the nozzle,
When the diameter of this extrusion hole is D, the interval between the extrusion holes is 2D
The number of strips extruded from the extrusion hole is guided into a shaping device, and cooling gas is blown onto the number of strips from above within the shaping device or immediately before the shaping device. 5VD/L≦V≦4.0VD/L (
However, v<V, where ■ is the take-up speed, D is the diameter of the extrusion hole, and ■ is the extrusion speed of the strip when freely extruded from the extrusion hole). shall be.

[Effect]

The method of this invention will be explained with reference to the drawings.

FIG. 1 is a side view showing an embodiment of the method of this invention,
1 is an extruder, 2 is a die attached to the tip of the extruder, 3 is a shaping device, 4 is a cooling nozzle for jetting cooling gas, and 5 is a take-off machine.

As shown in an enlarged view in FIG. 2, the die 2 has a large number of extrusion holes 21 having a hole diameter of D, arranged regularly or irregularly, and the envelope outer shape of the extrusion holes 21 is as follows. , are formed with holes spaced apart so that the cross-sectional shape is generally similar to the cross-sectional shape of the three-dimensional net-like body to be manufactured.

This hole spacing is 2DSLSI5D.

The shaping device 3 includes a rotating belt 31 on the bottom surface and a rotating roll 32 on the top surface.

It is preferable that the rotation of the rotating bell 1-31 and the rotating roll 32 be synchronized with the take-up speed of the take-up machine 5. A cooling nozzle 4 is disposed close to the rotating roll 32 on the upper surface, and is configured to spray cooling gas from above onto a large number of extruded strips. This cooling nozzle 4 consists of a slit hole or a small hole.

In the present invention, the cooling gas is preferably at least 30'C lower than the resin temperature of the strip when it is extruded from the die 2.

Note that the cooling nozzle 4 may be provided immediately before the rotating roll 32 (on the mouthpiece 2 side).

As the shaping device 3, in addition to the above-mentioned device, it is also possible to use a device made by assembling a plurality of rolls in a grid pattern to form a tube, or a device made by arranging fixed plates vertically and horizontally to form a tube. . When these rolls are assembled, from the gap,
In the case of a fixed plate, the cooling gas is ejected from a large number of pores or slits provided on the top surface.

Note that A is a cubic mesh body that is extruded from the die 2, shaped in the shaping device 3, and taken up by the take-up machine 5.

The thermoplastic resin melted in the extruder 1 is extruded into strips through the many extrusion holes 21 of the die 2, introduced into the shaping device 3, and taken out by the take-off machine 5 into a number of strips. The taking-up speed V by the taking-off machine 5 is set under the following conditions with respect to the speed (2) at which the material is freely pushed out from the nozzle 2.

However, v<V.

0,5 V D / L f-v ≦4.0 V D
/ L Under these conditions, the strips move in a meandering manner within the forming device 3, and the contacting portions of the foamed strips fuse together, forming a cross-sectional shape of the inner surface of the forming device 3. A three-dimensional net-like body A having approximately the same cross-sectional shape is formed and taken off by a taking-off machine 5.

In this invention, if a foaming agent is added to the resin and molded, the strips can be made into foamed ones, and if necessary, colorants, stabilizers, antistatic agents, fillers, plasticizers, etc. can be added. It may be added to the resin.

In this invention, the diameter and interval of the extrusion holes of the nozzle are set within the above-mentioned range, and the relationship between the extrusion speed and the take-up speed is as follows.
By setting the diameter and spacing of the extrusion holes of the die within the above-mentioned specific range, and by spraying cooling gas from the upper surface within or immediately before the shaping device 3, the die 2 is
When the strip extruded from the many extrusion holes 3 meanderingly bends, the blown gas cools the part near the upper surface strongly and weakly toward the lower surface. The more strongly cooled strips become stiffer, and the pinch of serpentine bending becomes greater.

Therefore, a three-dimensional network body having different densities in the thickness direction is obtained, in which the meshes are large at the upper surface and become smaller toward the lower surface, and the bulk density is also higher at the upper surface.

In this case, if the distance between the extrusion holes 21 is less than 2D, the strips will not meander and bend sufficiently, making it impossible to obtain a bulky cubic network. Furthermore, if the spacing becomes large, such as exceeding 15D, the welding of the strips becomes insufficient, making it difficult to obtain a desired cross-sectional shape.

On the other hand, if the strip withdrawal speed V is less than 0.5 VD/L, the strips will become clogged within the region of the shaping device 3, making it difficult to withdraw them. In addition, the surface of the resulting cubic network A may become rough, detracting from its appearance, and it is difficult to obtain a bulky product.

Furthermore, if the take-up speed V exceeds 4.0 VD/L, there may be no meandering at all, resulting in incomplete fusion of the strips.

In this invention, the thermoplastic resin used includes, for example, homopolymers such as polyethylene, polypropylene, polybutene, polystyrene, polyvinyl chloride, and polymethyl methacrylate, and monopolymers copolymerizable with monomers of these polymers. copolymers with polymers or mixtures of homopolymers or copolymers thereof are used.

〔Example〕

Equipment; Extruder: Diameter: 50mm, barrel length: 1000mm, mouthpiece: Plate with 5 rows of 5 rows of extrusion holes with a diameter of 1mm, extrusion hole spacing: 7
Dragon.

Shaping device: 800mm width, 1000u+ length rotating heald (bottom side, belt is 40 mm stainless steel mesh) and a roll 800 mm wide and 30 mm diameter (bottom side). A cooling nozzle with a width of 800 mm and two slits is installed adjacent to this rotating roll.

Resin: Ethylene-vinyl acetate copolymer (Ultracene υE54 Toyo Soda Co., Ltd.) Extrusion speed (
V); lom/min With the above device, the strip extruded from the die at a resin temperature of 170°C is introduced into a forming device in which the belt on the lower side and the roll on the upper side are maintained at a spacing of 30 mm, and the strip is extruded from the cooling nozzle at 3 nm. ? While blowing air at a temperature of 20° C./min at a rate of 20° C./min, the sample was taken at two different take-up speeds of 1, 0, and 5,0 m/min.

The resulting products were as shown in Table 1.

Note that the take-up speed is 0.5.7.0 m, which is outside the scope of this invention.
Comparative Examples 1 and 2 and Table 1 show the results of an experiment conducted in the same manner as in the above Example except that the heating time was changed to /min.

Further, the take-up speed is set to 1.0 or 1.0, respectively, within the scope of the present invention.
The results of experiments conducted in the same manner as above except that the speed was set at 3.0.5.0 m/min and the blowing of cooling gas from the cooling nozzle was stopped are also shown in Table 1 as Comparative Examples 3 to 5.

(Margins below) Table 1 Table 1 (Continued) [Effects of the Invention] As explained above, this invention uses a die having a large number of extrusion holes, and a large number of thin strips extruded laterally from the die. Cooling gas is sprayed from the top of the strip in or just before the shaping device to cool the top surface of the strip more strongly, bend it in a meandering manner, and fuse the contact parts with each other to form the desired shape. Because of this, it is possible to easily manufacture a three-dimensional network body in which the mesh size in the thickness direction is continuously changed. Therefore, this three-dimensional net-like body can be used in a wide range of applications, such as cushioning materials and filter materials.

In addition, it can be manufactured in one simple process, resulting in high productivity, and since gas is used for cooling, a drying process is unnecessary, resulting in lower energy costs, equipment costs, etc.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the method of this invention;
The figure is a perspective view of the cap in the above embodiment. 1--extruder, 2--mouthpiece, 3--forming device, 4-cooling nozzle, 5--take-off machine.

Claims (1)

[Claims] 1. When extruding thermoplastic resin laterally from a nozzle attached to the tip of the extruder, a large number of extrusion holes are provided in the nozzle, and when the diameter of the extrusion holes is D, the interval L between the extrusion holes is 2D. The number of strips extruded from the extrusion hole is guided into a shaping device, and cooling gas is blown onto the number of strips from above within the shaping device or immediately before the shaping device. 5VD/L≦v≦4.00VD
/L (where v<V, where v is the withdrawal speed, D is the diameter of the extrusion hole, and V is the extrusion speed of the strip when freely extruded from the extrusion hole). A method for producing a three-dimensional thermoplastic resin network, characterized by: