JPS5950489B2 - Multilayer synthetic resin body manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises two or more synthetic resins layered,
A field where different synthetic resins are in contact with each other.

The surface has a cross-sectional structure with periodic irregularities in a direction perpendicular to the surface of the multilayer synthetic resin body, and the resin sandwiched inside is arranged diagonally or in a zigzag pattern. The present invention relates to a multilayer synthetic resin body manufacturing apparatus for manufacturing multilayer synthetic resin bodies such as multilayer films and sheets. Conventionally, in multilayer synthetic resin bodies, interfaces between layers are often flat.

In that case, there is no problem if resins with good adhesiveness are in contact with each other, but if resins with poor adhesiveness are in contact with each other, a layer made of a material with adhesiveness is added to both resins. Practically acceptable adhesive strength could not be achieved unless an adhesive component was inserted between the resins or mixed with both resins or one of the resins. Adding a new layer increases the number of layers, complicates the manufacturing equipment, and makes the adhesive layer components expensive.
Due to the presence of the adhesive layer, the properties of the entire multilayer body may deteriorate. In some cases, there may not be suitable adhesive materials for both resins. Further, similar difficulties arise when an adhesive component is mixed. Therefore, it would be ideal if a multilayer synthetic resin body with sufficient adhesive strength could be produced without using such adhesive components. The inventor of the present invention has developed a multilayer synthetic resin body having a cross-sectional structure as shown in FIGS. invented the production of These are a combination of two types of resin in a layered manner. Figure 1 shows a case where the interface where different resins come into contact has periodic indentations in the direction perpendicular to the surface of the multilayer synthetic resin body. , FIG. 2 shows a case with periodic unevenness. B represents a resin layer serving as a surface layer of the film, A represents a resin layer embedded within the film, the MD direction represents the film winding direction, and the TD direction represents a direction perpendicular to the winding direction.

P indicates the periodic indentation of the interface where different resins come into contact, or the pitch of periodic irregularities. SLS2 is resin A per unit cross section in the thickness direction (for example, between P),
The area occupied by B, d is the film thickness, Wl, W2, W3
represents the width in the thickness direction of periodic indentations or periodic irregularities of resin A, W1 is the narrowest width, W2 is the average width,
W3 indicates the widest width.

INT represents the penetration of resin A into resin B in the MD direction.

These multilayer synthetic resin bodies were initially manufactured using, for example, equipment as shown in FIGS. 3 to 6.

In the apparatus shown in FIG. 3, several resin supply passages 2, 3, 3a extending in the axial direction are provided inside a vertical central fixed shaft 1 without penetrating each resin supply passage 2, 3, 3a.
The upper ends of 3a are opened toward the outer circumferential surface 4 of the central fixed shaft 1, and a discharge plate 7 is provided on the upper horizontal surface of the rotary die 6, which is rotatably provided on the outer circumference of the central fixed shaft 1 by the operation of a chain wheel 5. Attach the outer peripheral surface 4 of the central fixed shaft 1 to the upper surface of the discharge plate 7.
Another ring groove 10 is provided between the double ring grooves 8 and 9 concentrically with the ring grooves 8 and 9, and the two ring grooves 8 and 9 and the ring groove 10 between them are connected to a rotary die. The resin supply passages 3, 3a, 2 in the central fixed shaft 1 are communicated through separate resin passages 11, 11a, 12 in the central fixed shaft 1, respectively,
Fixed dies 14 and 15 having one ring-shaped die lip 13 communicating with two ring grooves 8 and 9 and a ring groove 10 therebetween are provided in close contact with the upper surface of the discharge plate 7.

The discharge plate 7 has the structure shown in FIGS. 4 to 6, and the ring grooves 8 and 9 provided on the upper surface of the discharge plate 7 and the ring groove 10 between them have wide portions 8a, 9a, and 10a, respectively, in the circumferential direction. It was established periodically.

Moreover, the wide portions 8a, 9 of the ring grooves 8, 9 on both sides
a and the wide part 10a of the ring groove 10 in the center are inserted alternately, and each ring groove 8, 9, 10 is a vertical hole provided in the wide part 8a, 9a, 10a, respectively. 8b, 9b, 10b and ring grooves 8C, 9C, I0C provided on the lower surface of the discharge plate 7 to communicate with resin passages 11, 11a, 12 in the rotary die 6. By the way, the third
~ If a multilayer synthetic resin body is manufactured by rotating the rotary die 6 using a device using a discharge plate 7 as shown in Fig. 6, the resin that has proceeded from the resin passages 11, 11a, and 12 will be , are continuous in the circumferential direction up to the bottom of the discharge plate 7, but when passing through the holes 8b, 9b, 10b in the discharge plate 7 section, they are once separated in the circumferential direction, and then the ring grooves 8, 9 , 10 parts may be joined again in the circumferential direction.

As a result, this separation caused many undesirable phenomena in which physical properties such as impact strength and tear strength of the molded article were significantly impaired. The present invention aims to eliminate this drawback. By eliminating the discharge plate and processing the upper surface of the rotating die, the separation and recombination of the resin in the circumferential direction is eliminated, and the multilayer synthetic resin body to be molded is It is designed to further improve physical properties such as impact strength and tear strength.

Next, the present invention will be explained with reference to embodiments shown in the drawings. 7 to 10 show an embodiment of an extrusion head for producing multilayer synthetic resin bodies such as multilayer films.

In the apparatus shown in FIG. 7, several resin supply passages 2, 3, 3a extending in the axial direction are provided inside a vertical central fixed shaft 1 without penetrating each resin supply passage 2, 3, 3a.
Each resin supply channel is opened at the upper end of 3a toward the outer peripheral surface 4 of the central fixed shaft 1, and is provided inside a rotary die 6 rotatably provided on the outer periphery of the central fixed shaft 1 by the operation of a chain wheel 5. 2, 3, 3a are provided with resin passages 11, 12, 12a communicating with each other, and each resin passage 11, 12, 12a inside the rotary die 6 is connected to the rotating plane part of the upper end of the rotary die. Each ring-shaped opening 16, 17 of each resin passage 11, 12, 12a is opened in a concentric ring shape.
, 18, portions 16a, 17a, which differ in width in the radial direction.
18a are provided periodically in the circumferential direction, and these openings 16
, 17, 18, fixed dies 14, 15 having one ring-shaped die lip 13 communicating with all the openings 16, 17, 18 are provided in close contact with the upper surface of the rotary die 6.

As shown in FIGS. 8 to 10, the upper ends of the openings 16, 17, and 18 provided on the upper surface of the rotary die 6 are provided with wide portions 16a, 17a, and 18a, respectively, around the circumference. provided periodically in the direction.

Moreover, the wide portions 1j6 of the openings 16 and 17 on both sides
a, 17a and the wide part 18 of the central opening 18
A was set in a state where they were interleaved alternately. Wide parts 16a, 17a of openings 16, 17, 18 provided in rotating die 6
, 18a are tapered as shown in the figure to improve resin flow. Note that the openings 16, 17,
The shape of the opening 18 is not limited to that shown in FIGS. 8 to 10. For example, as shown in FIG. The openings 16, 17, and 18 may be formed into a ring shape with the same width, or may be formed into a wavy shape with the openings 16, 17, and 18 being inserted into each other, as shown in FIG.

The rotary die 6 may be rotated only in one direction, or may be oscillated or vibrated in the horizontal direction with a constant period and amplitude.

It is preferable that the resin in the central fixed shaft 1 flows continuously to the resin collection chamber 19 surrounded by the dies 14 and 15, but in order to integrate the constituent parts 20, 21, 22, and 23 of the rotary die 6, A connecting portion using a bolt 24 is provided in the middle, and a partially discontinuous portion 25 is provided at that portion.

At this discontinuous portion 25, the resin that has continuously flowed is
It will be divided at some point, but this is Dairitsu 1.
Since the resin is also sufficiently bonded during the subsequent transfer, rather than in the discharge area close to 3, the physical properties of the multilayer synthetic resin body are not affected in any way. Although not shown, a heating device is provided in the rotary die 6, etc., so that the resin that is plasticized and supplied by separate extruders is not individualized in the rotary die 6, the dies 14, 15, etc. ing.

For heating, wrap an electric resistance plate heater around the outside of the rotary die 6, or use a rod-shaped cartridge heater around the rotary die 6.
Insert it in a position where it will not interfere with mechanical operations such as
Alternatively, it is preferable to heat by using a combination of both.
Furthermore, when molding a multilayer synthetic resin body continuously for a long time,
Depending on the type of resin and molding conditions, heat may be generated, making the temperature and viscosity higher than necessary, which may adversely affect the physical properties of the resin. In that case, the heating by the heater must be stopped, or conversely, it must be cooled, so it is recommended to provide a cooling medium passage inside the rotary die 6, etc. The two types of resins plasticized by two extruders are passed separately through the resin supply path 2 and the resin supply paths 3 and 3a provided in the central fixed shaft 1, and are then transferred to the seventh extruder.
In the figure, it is being pushed upward from below.

Resin B, which is the basis of a multilayer synthetic resin body such as a film or sheet, rises through the resin supply channels 3 and 3a. If the flow rates of resin passing through the resin supply channels 3 and 3a are approximately equal, the pattern of the multilayer synthetic resin body will be the same when viewed from the inside and outside, but depending on the manufacturing purpose, the flow rates of the resin supply channels 3 and 3a may be It is also possible to change. Although not shown, a flow rate control valve is provided that can arbitrarily change the flow rate of the resin in the resin supply paths 3 and 3a, which are supplied separately from the single extruder. The resin B extruded through the resin supply channels 3 and 3a is always continuously supplied into the resin channels 12 and 12a of the rotary die 6. Resin passage in rotary die 6] 2, 1
2a is in contact with the outer peripheral surface 4 around the central fixed shaft 1, and is rotated together with the rotary die 6 by the rotational force applied by the sprocket 5. Then, resin B is diced 14,1
An opening 1 is formed on the inner and outer circumferential surfaces of the resin collecting chamber 19 surrounded by 5.
It is continuously discharged from 7 and 18. On the other hand, the patterned resin A supplied from another extruder (not shown) is continuously pushed up through the resin supply passage 2 in the central fixed shaft 1, and is pushed up through the resin passage of the rotary die 6. 11, and the resin A is continuously discharged from the opening 16 into the center of the resin collection chamber 19.

Note that the resin passages 11, 12, 12a provided on the inner circumferential surface of the rotary die 6 in contact with the central fixed shaft 1 are continuously provided in a circular shape, and no matter how much rotation or rocking, ,
Resin is continuously supplied from resin supply paths 2, 3, and 3a of the central fixed shaft 1. In this way, the resin A is continuously discharged from the central opening 16, and the resin B is continuously discharged from the openings 7 and 18 on the inner and outer peripheral surfaces. rotates or oscillates in the circumferential direction, and each opening 16, 17, 18 has wide portions 16a, 17a, ]8a as described above, so that the discharged resin A , B are fixed dice 14, 15
The resin enters the resin collection chamber 19 surrounded by
It is discharged as a multilayer synthetic resin body such as an annular film or sheet having a cross-sectional shape as shown in the figure.

After discharging, as in normal inflation molding, a fixed amount of air can be continued to be supplied from the air inlet hole 26 provided in the central fixed shaft 1, or it can be sealed and evenly supplied from the outside of the resin extruded into a cylindrical shape. A cooling medium is sprayed onto the material to solidify it, and then it is wound up. The cross-sectional structure in the thickness direction of a multilayer synthetic resin body such as a cylindrical film or sheet shown in FIGS. 1 and 2 changes depending on the shape of the discharge plate and molding conditions.

The pitch P shown in FIGS. 1 and 2 decreases as Pd in FIG. 8 decreases, decreases as the number of rotations of the rotary die increases, and increases as the film take-up speed increases. Area ratio S, /S occupied by resins A and B per unit cross section in the thickness direction.

is related to the discharge amount ratio of resins A and B. Film thickness d
increases as the total discharge amount of resins A and B increases, and decreases as the film take-up speed and blow ratio increase. The W1/d ratio is the narrow width A of the opening 16 and the narrow width A of the opening 17.
, 18 wide width B. It depends on the ratio between the resins A and B, and the discharge amount ratio between the resins A and B. Similarly, the W2/d ratio is
Wide width A. It depends on the wide width B2 between the openings 17 and 18, and on the discharge amount ratio of the resins A and B. The W1/W2 ratio is the narrow width A of the opening 16 and the wide width A of the opening 16. Depends on the ratio. By appropriately selecting the shapes and molding conditions of the openings 16, 17, and 18, the interfaces where different resins of the multilayer synthetic resin body come into contact can be made not smooth but periodically in the direction perpendicular to the surface of the multilayer synthetic resin body. The multilayer synthetic resin body can have deep indentations or periodic irregularities, and the specificity of the structure in the thickness direction of this multilayer synthetic resin body increases the adhesive strength between the layers.

Hereinafter, the present invention will be specifically explained with reference to Examples.

The examples were carried out by the inflation method. Examples and Comparative Examples As resin A, nylon 6 (UBE nylon 1013B
, flow ratio 230℃-3g/Min), resin B
as low density polyethylene (UBE polyethylene UBE
Cl8O, MIO. 8) and the apparatus of the present invention shown in FIGS. 7 to 10, a multilayer film having a cross-sectional shape as shown in FIG. 1 was molded.

The film discharge temperature was 240°C, and the rotation speed of the rotary die 6 was 40r. p. A cylindrical film was formed using m, blow ratio of 1.3, and film winding speed of 5 m/min to obtain a multilayer film with a film width of 245 mm and a thickness of 100 μm. However, under such molding conditions, two types of multilayer films I and ll with different thicknesses were molded.

In film I, the average thickness W2 of resin A is 30μ, and the average thickness d - W2 of resin B, which is the sum of both surface parts, is 70μ.In film 11, the average thickness W2 of resin A is 20μ, which is the sum of both surface parts. The average thickness d-W2 of resin B is 80μ. The physical properties of the multilayer film obtained by molding using the apparatus of the present invention were examined under the same molding conditions as described above using a conventional apparatus having the discharge plate 7 shown in FIGS. 3 to 6. Table 1 shows a comparison of the physical properties of a multilayer film having the same thickness as the above film obtained by molding under the following conditions.

However, the width of the films obtained using the conventional apparatus is 410 mm. In addition, in the table, in the measurement direction, M
D indicates the molding direction, and TD indicates the perpendicular direction. As is clear from Table 1, when the apparatus of the present invention is used, the tear strength and impact strength are significantly improved, and the tensile strength at break in the perpendicular direction and the tensile elongation strength are significantly improved compared to those formed using the conventional apparatus. It can be seen that the temperature has also improved significantly.

In this way, in the present invention, since the structure as described in the claims is adopted, the resin is once separated near the upper opening or die lip of the rotary die, and then recombined. The resin is always fed continuously.

Furthermore, an interface where the resins penetrate into each other can be obtained. Therefore, the adhesive strength between resins can be significantly increased, and a multilayer synthetic resin body with high tear strength and impact strength can be reliably and easily obtained. Of course, the resin A discharged from the central opening is completely surrounded by the resin B discharged from the openings on both sides, making it possible to obtain a multilayer synthetic resin body with a beautiful pattern and different properties. At the same time, effects such as composite films whose properties are strengthened by overlapping resins having the same properties can also be obtained.

[Brief explanation of drawings]

1 and 2 are longitudinal sectional views showing multilayer synthetic resin bodies having different cross sections obtained by the apparatus of the present invention, and 3.
The figure is a longitudinal sectional view of a conventional device similar to the present invention, FIG. 4 is a perspective view showing a part of the discharge plate shown in FIG. 3, and FIGS. 5 and 6 are sectional views taken along the line Vv in FIG. 4, respectively. and a sectional view taken along the line VI-VI, FIG. 7 is a longitudinal sectional view showing one embodiment of the present invention, and FIG. 8 is a perspective view showing a part of the upper part of the rotary die shown in FIG.
9 and 10 are sectional views taken along line IX-1 and XX of FIG. 8, respectively, and FIGS. 11 and 12 respectively show a part of a rotary die showing another embodiment of the present invention. FIG. 1... Central fixed shaft, 2, 3, 3a...
Resin supply path, 6...Rotating die, 7...
Discharge plate, 8, 9, 10...Ring groove, 11, 1
1a, 12... Resin passage, 13... Die lip, 14, 15... Fixed die, 16, 1
7, 18...Opening, 19...Resin gathering chamber, 26...Air inlet.

Claims (1)

[Scope of Claims] 1. A rotary die is provided on the outer periphery of a vertical central fixed shaft, and several resin passages are connected, one each to several resin supply passages provided inside the central fixed shaft. Each resin passage inside the rotary die is opened in the shape of several concentric rings on the rotating plane of the rotary die. parts with different widths in the direction,
A manufacturing device for a multilayer synthetic resin body, comprising ring-shaped die lips provided periodically in the circumferential direction and communicating with all the openings above the openings. 2. The apparatus for manufacturing a multilayer synthetic resin body according to claim 1, wherein the inner surface of the wide part of the opening provided in the rotary die is tapered.