JPS644897B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is used in the technical field of multilayer dies connected to synthetic resin extruders. (Prior Art) The above-mentioned multilayer die for producing a strip-shaped multilayer film in which several types of resins are laminated has been widely used. For example, the device disclosed in Japanese Patent Application Laid-Open No. 54-124067 has a replaceable insert in the insertion hole at the center of the die body, and a plurality of resin channels are formed around the outer circumference of the insert in the shape of a flat coat hanger. The downstream ends of these flat coat hanger-shaped channels are assembled into one slit channel. In this way, the various resins extruded from the downstream end of the flat coat hanger-like flow path of the plurality of resin flow paths flow into the slit flow path in layers, and a strip-shaped multilayer film in which several types of resin are laminated is formed. Manufactured.
The resin flow path formed on the outer periphery of the insert is shaped and dimensioned to suit each resin used, so that a highly accurate multilayer film can be obtained. (Problems to be Solved by the Invention) However, in the conventional multilayer die described above, the insert is inserted into the die body and a flow path is provided on the outer periphery of the insert, so the inside of the insert insertion hole of the die body is The difference in shape and dimension between the shape and the outer shape of the insert must be processed with high precision. If this processing accuracy is poor, it may not be possible to insert the resin, or even if the resin can be inserted, the gap between them will be large, resulting in mixing of different resins due to leakage, and the quality of the resulting multilayer film will be poor. This invention attempts to solve these problems. (Means for solving the problems) Means for solving the problems described above will be explained with reference to the drawings. The multilayer die of the present invention has a plurality of widening plates 1 stacked so that the stacking thickness is constant, and each widening plate 1
It is a multilayer die that can be replaced, and the die body 3 has a recessed cavity 3d.
A flat channel 6 is provided between the cavity 3d and the die outlet 3e, and each widening plate has substantially parallel surfaces 1a, 1a, and a molten resin channel 2 is provided in the widening plate 1. , this molten resin flow path 2 passes through the inlet flow path 2a, and then passes through one side 1a of the widening plate 1.
The outlet 2b is formed to have the same width as the flat channel 6 and to be connected to the outlet 2b, and the assembly of widening plates 1 formed in this way is inserted into the cavity 3d. This is a multilayer die characterized by comprising a converter 8 communicating with the inlet channel 2a of the widening plate 1. (Function) Next, the function of the above means will be described. First, in the multilayer die of the present invention, since the widening plates 1, 1... are sandwiched between the cavities 3d of the die body 3, even if the thickness dimensional accuracy of these widening plates 1 is somewhat poor, the flatness of both surfaces 1a, 1a is If the conditions are good, these contact surfaces will come into close contact with each other without any gaps. In order to manufacture a multilayer film using the multilayer die of the present invention assembled in this way, various molten synthetic resins are first passed through the converter 8,
The flow path 2 of each widening plate 1, 1...
into the inlet channel 2a. These various types of molten synthetic resins are widened at the outlet 2b on the downstream side of the flow path 2, that is, become a flat flow spread laterally. This flat flow is laminated in a flat channel 6 formed in the die body 3 and extruded as a multilayer film. At this time, since the widening plates 1 are assembled without any gaps between them as described above, the molten synthetic resin pumped through each channel 2 does not leak and mix, and the resulting multilayer film has a high quality. is extremely good. (Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. Reference numerals 1, 1, 1, and 1 are widening plates that are each formed to have the same shape (the outer dimensions are the same, and the dimensions of the flow paths described later are also substantially the same). A resin flow path 2 is bored in the plate 1 . The cross-sectional shape of the inlet channel 2a on the inlet side (left side in FIGS. 1 and 2) of the channel 2 is circular. The downstream side of the flow path 2 (the right side in FIGS. 1 and 2) is one side 1 of the plate 1.
Groove-shaped outlet 2 at a (top surface in Figure 1)
b. As shown in FIG. 2, the outlet 2b is expanded in the width direction (in the vertical direction in FIG. 2) and formed flat (in the shape of a so-called coat hanger). 3 is a die body. The die body 3 includes an upper side (upper side in FIG. 1) 3a, a lower side (lower side in FIG. 1) 3b, and a side lid 3c. The plates 1, 1, 1, 1 are stacked and held between the respective recesses or cavities 3d of the upper side 3a and the lower side 3b, and are fastened by means of bolts 4, 4, 4, 4. Knock pins 5, 5, 5, . . . are fitted between the plates 1 for mutual positioning. Although the details are not shown, the two side lids 3c are fastened to each plate 1 and the upper side 3a by known fastening means.
and the lower side 3b, respectively. The die body 3 has an outlet 2b on the downstream side of the flow path 2 of each plate 1 (in FIGS. 1 and 2,
A flat strip channel 6 that joins the right end of the plate 1 is bored on the opposing surface of the joint between the upper side 3a and the lower side 3b. A flexible lip 7 is formed on the outlet side of the flow path 6 (the right end in FIG. 1), and the gap between the total thickness of each plate 1 and the bottom of the cavity 3d on the upper side 3a and the lower side 3b is formed. The thickness of the outlet of the flow path 6 determined by the difference between
Screw means 7a are provided for adjusting. That is, by screwing the screw means 7a into the upper side 3a, the flexible lip 7 is bent,
The dimension of said S can be made small. 8 is a converter, in which each plate 1 is attached to one plate 1 with two bolts 9, 9, and then bolts 10, 10, 10, 1 are attached to each plate 1.
Each plate 1 and converter 8 are assembled to the body 3 by the following means. The converter 8 has resin injection ports 11a, 11
b, 11c are opened. An outlet 12a branches from the inlet 11a and connects with each inlet side 2a of the top and bottom plates 1 in FIG.
A flow path is bored to reach 12a. Reference numerals 13 and 13 indicate flow rate control valves provided at locations where the inlet 11a branches to the outlets 12a and 12a. Entrance 11
A flow path is drilled from b to an outlet 12b that connects with the inlet side 2a of the second plate 1 from the top in FIG. Furthermore, from the entrance 11c, the first
Inlet side 2 of the third plate 1 from the top in the figure
A flow path is drilled to reach an outlet 12c that is connected to a. The order of explanation of each structure described above is from the important parts of this invention, and the order of assembling this die is to attach each plate 1 to the converter 8, and then tighten both of them to the body 3. I want it to be understood that there is. The operation of the above-mentioned embodiment will be described below. When a certain type of molten resin is pressurized from the inlet 11a, this resin branches from the inlet 11a, the flow rate is adjusted by the valve 13, passes through the outlets 12a, 12a, and flows to the top 1 and 1 in FIG. It reaches the inlet channels 2a, 2a of the lower plate 1. Furthermore, it reaches the flow path 6 via the flow path 2 and outlet 2b of each plate 1. On the other hand, different types of molten resin are press-fitted from the inlets 11b and 11c, respectively. The resin press-fitted from the inlet 11b passes through the outlet 12b, reaches the inlet channel 2a of the channel 2 of the second plate 1 from the top in FIG. It reaches 6. Similarly, the resin press-fitted from the inlet 11c reaches the flow path 6 via the flow path 2 of the third plate from the top in FIG. Thus, the resin in the flow path 6 has four layers in FIG. 1: the uppermost layer and the lowermost layer are the resin from the inlet 11a, the upper layer between them is the resin from the inlet 11b, and the lower layer is the resin from the inlet 11c. In this case, various resins are used for each plate 1.
Since the resin has already been expanded and flattened in the width direction in the channel 2, and these flattened resins are stacked on top of each other in the body 3, the resin layer extruded from the channel 6 has good thickness accuracy. In the above embodiment, a four-layer die was explained.
Similarly, if plates 1 are stacked in multiple layers,
Dies with five or more layers can also be easily formed. In yet another embodiment shown in FIG. 4, the number of plates 1 is three in total;
In this case, the center plate 1 in the figure is the first
It is twice as thick as the plate 1 in the figure, and the other upper and lower plates 1 are identical to those in FIG. Of course, in this case, the resin injection port of converter 8 is 1.
There are two exits, 1a and 11b, and the exits are 12a and 11b.
It is necessary to prepare channels with different flow paths corresponding to the number of plates 1, such as a total of three locations, 12b and 12a. This example shows that by reducing the number of plates 1, it can be converted into a die for a sheet with a small number of layers. Furthermore, in this embodiment, in order to improve the flow of the resin at the entrance of the flat channel 6, the plate 1 may be tapered as shown by the two-dot chain line. However, by changing the plate 1 while keeping the die body 3 the same, the number of resin layers can be changed.
The fact that the shape of the passage etc. can be changed is the same as in the previous embodiment. Furthermore, in these embodiments, in the plate 1, the cross-sectional shape of the outlet 2b for widening, the pinching angle of the part that expands into a fan shape, the flow path gap of this fan-shaped part, etc. should be designed in accordance with the flow characteristics of the resin. This makes it possible to ensure the uniformity of the flow rate in the width direction, that is, the thickness accuracy. Therefore, if you want to change the type of resin to be supplied, use plate 1.
It is possible to construct a multilayer die by stacking multiple pieces or stacking them to a certain thickness, so when changing the number of layers, the layer configuration, the type of resin, etc., it is necessary to replace plate 1. Alternatively, in addition to this replacement, the function of the die can be changed with minimal parts replacement, such as replacing the converter 8. (Effects of the Invention) The multilayer die of the present invention has the following effects. (1) Since multiple widening plates with substantially parallel surfaces on both sides are stacked and sandwiched in the cavity space formed in the die body, the machining dimensions of the die body and widening plates, especially in the thickness direction, do not have to be very precise. In both cases, the resins in the channels formed in each widening plate do not leak and mix. (2) Thereby, a multilayer die capable of producing a multilayer film of good quality can be provided easily and inexpensively.

[Brief explanation of drawings]

Figures 1 to 3 all show one embodiment of the present invention, with Figure 1 being a longitudinal side view and Figure 2 being a side view of the first embodiment.
FIG. 3 is a cross-sectional view taken along arrows in the figure, and FIG. 3 is a partially cross-sectional side view. FIG. 4 is a longitudinal sectional side view of another embodiment. 1... widening plate, 1a, 1a... both sides, 2
... Molten resin channel, 2a... Inlet channel, 2b...
Exit, 3...Die body, 3a...Upper side, 3b...
...Lower side, 3c...Side lid, 3d...Cavity, 3
e...Die outlet, 6...Flat channel, 8...Converter.

Claims (1)

[Scope of Claims] 1 A multilayer die in which a plurality of widening plates are stacked so that the thickness is constant and each widening plate can be replaced, comprising: (1) a cavity and a flat plate between the cavity and the die exit; a die body provided with a flow path; (2) both sides of the individual widening plates are substantially parallel planes, the molten resin flow path is widened on one side of the widening plate after passing through the inlet flow path, and the flat flow is formed at the outlet thereof; (3) a converter communicating with the inlet flow path of the widening plate; and (3) a converter connected to the inlet flow path of the widening plate. A multilayer die featuring