JPH0517222Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a die for manufacturing plastic sheets.

[Prior Art] Conventionally, plastic sheets (hereinafter referred to as sheets) in which individual optical fibers are closely arranged in a row or multiple rows, such as plastic optical fiber sheets used for various image guides, sensor heads, etc. ), the molten polymer is discharged from a nozzle with a large number of discharge holes arranged close to each other in a linear or staggered manner, and the threads are arranged in parallel with each other before the molten polymer is cooled and solidified. A cap that forms a band-shaped sheet by fusing and converging it is known.

As for the specific structure of such a spinneret, for example, as in the spinneret described in Japanese Patent Publication No. 54-43605 shown in FIG. The sheath component B is introduced through the introduction hole 3 drilled in the chamber, and both components are merged in the composite chamber 4 below to form a composite yarn with a core-sheath double structure, and then spun from the discharge hole 5. A composite spinning spinneret (hereinafter referred to as the former conventional spinneret) in which a plurality of spinning holes are arranged closely in a linear or staggered manner is common.

By the way, as mentioned above, plastic optical fibers are composite fibers with a so-called core-sheath double structure, in which a core component polymer is coated with a sheath component polymer whose optical refractive index is lower than that of the core component polymer. In order to obtain a high-quality sheet with excellent light transmission characteristics, flexibility characteristics, etc., the prerequisite is to first ensure that the individual yarns have uniform roundness, concentricity, sheath thickness, etc. It is important that the yarn is spun and that there is no contact with adjacent yarn immediately after it is discharged from the spinneret.

JP-A No. 61-63708, shown in Fig. 5, is a cap designed to improve the roundness, concentricity, and uniformity of the thickness of the sheath component of the core and sheath components in such core-sheath composite fibers. The cap stated in the official gazette (hereinafter referred to as
The latter is called the conventional cap. )It has been known.

This cap has a core component polymer A in the thread cross section.
In order to prevent the eccentricity of the sheath component polymer B and the outer circumferential surface 7 of the core component spinning tube 6 and the sheath component polymer B, as shown in the figure,
A cylindrical metal filter 10 is attached to the discharge hole 9 of the sheath component polymer B formed by the inner circumferential surface 8 of the spinning hole, thereby maintaining the concentricity of both components. .

[Problems to be solved by the invention] However, the former conventional die was originally proposed as a die for producing sea-island composite fibers, and the lower end 1 of the tube 1, which is the inflow tube for the core component polymer A,
2 is a composite chamber 4 that forms a core-sheath double structure with respect to the lower surface 13 of the composite plate 2 to stabilize the formation of a sea-island composite flow.
They were arranged in such a position that they protruded in the direction.
Such a positional relationship between the tube 1 and the composite plate 2 is preferable for forming a high-quality sea-island composite structure, but even if assembled in this positional relationship, the lower end 12 of the tube 1 Since it protrudes from the lower surface 13, it is difficult to inspect the concentricity of the tube 1 with respect to the introduction hole 3, and in reality, only caps with concentricity problems can be obtained.

Furthermore, in the latter conventional nozzle as well, since the cylindrical metal filter 10 is attached to the discharge hole 9 of the sheath component polymer B as described above, the distance between the adjacent discharge hole is inevitably wide, and even if the lower part of the nozzle Even if the fibers are focused using a guide or the like (not shown), the contact angle between the fibers becomes large, resulting in a problem that only a sheet with poor permeability can be obtained. Furthermore, since the discharge holes 13 of the core component polymer A and the discharge holes 14 of the sheath component polymer B are finished on the same surface on the lower surface 15 of the cap, the discharge holes 13 and 14 of each
It is easy to obtain the influence of the processing accuracy, and the core-sheath composite yarn is actually formed after it leaves the spinneret, and during this process it is affected by the airflow of the spinning tube (not shown). There were problems such as the inability to obtain a sheet of excellent quality with good adhesion to the interface between the core and sheath.

The purpose of this invention is to precisely arrange the discharge hole of the core component polymer with respect to the discharge hole of the sheath component polymer, and to form both components into a complete core-sheath double structure before reaching the nozzle discharge hole. By doing so, we have solved the above problems and created a base that can manufacture a plastic sheet with an excellent quality core-sheath dual structure in which individual optical fibers are closely arranged in a row or in multiple rows. It is on offer.

[Means for solving the problems] The structure of the present invention to solve the above problems is as follows:
It is as follows. That is, an upper plate 2 in which a plurality of tubes 21, which are inflow tubes for the core component polymer A, are suspended in close proximity in a row, and at least one inflow hole 22 for the sheath component polymer B is bored.
0 and a composite plate 23 arranged on the lower surface side of the upper plate 20.
A distribution chamber 25 for the sheath component polymer B that communicates with the inflow hole 22 is formed in the composite plate 23, and a chamber 25 that communicates with the distribution chamber 25 and is concentric with each of the plurality of tubes 21 is formed in the composite plate 23. placed, and
An introduction hole 26 having an inner diameter larger than the outer diameter of the tube 21 is bored, and a thread in which the core component polymer A discharged through the introduction hole 26 is coated with the sheath component polymer B is placed in the lower part of the mouthpiece. , in a plastic sheet manufacturing die provided with a convergence guide for converging in rows to form a sheet, the lower end 30 of the tube 21 and the lower surface 31 of the composite plate 23 are arranged substantially on the same plane, and the Below the composite plate 23, a composite chamber 28 corresponding to the introduction hole 26 and provided concentrically for each tube 21, and a discharge hole 2 communicating with the composite chamber 28 are provided.
This die for producing plastic sheets is characterized in that it includes a lower plate 27 on which 9 is formed.

EMBODIMENT OF THE INVENTION Hereinafter, this invention will be specifically explained based on drawing which shows one Example.

FIG. 1 is a longitudinal sectional view of a die for manufacturing plastic sheets according to this invention.

In the figure, reference numeral 20 denotes an upper plate, on which a plurality of tubes 21 of a certain length, which are inflow tubes for polymer A as a core component, are fixed in a line in the left-right direction in the figure. In this embodiment, the tubes 21 are arranged in a single row, but they may be arranged in multiple rows or in a staggered arrangement. Further, the interval between the tubes 21 is not particularly limited, but when the diameter of the spun yarn is 0.01 to 1 mm (however, the diameter after solidification), it is preferably in the range of about 1 to 5 mm. Furthermore, inlet holes 22 for polymer B are bored on both sides of the plurality of tubes 21 . 23 is a composite plate for forming a distribution chamber 25 for polymer B by inserting an intermediate plate 24 in the lower part of the upper plate 20; A plurality of B introduction holes 26 are bored concentrically corresponding to the tube 21. 27 is the above-described process in which the polymer A flowing from the pipe 21 and the polymer B flowing from the inflow hole 22 through the distribution chamber 25 and the introduction hole 26 join together to form a composite yarn with a double structure of the heart sheath. A composite chamber 28 provided concentrically for each tube 21, and a discharge hole 29 connected to this composite chamber 28.
It is a lower board equipped with.

These upper plate 20, intermediate plate 24, composite plate 23, and lower plate 27 have their respective boundary surfaces finished with high precision, and bolts (not shown) are inserted through both ends of each member. , are fixed to each other with nuts to form a composite spinning nozzle.

By the way, in the above-mentioned cap, the core component polymer A
However, in order to obtain a high-quality core-sheath double structure yarn with no eccentricity or deformation with respect to the sheath component polymer B, the arrangement position of the tube 21 with respect to the introduction hole 26 must be precisely set.
That is, it is important that the concentricity is arranged with high precision, and that both the inner and outer diameters of the tube 21 and the inner diameter of the introduction hole 26 are machined with high precision.

In order to obtain a cap that satisfies these processing conditions, the cap shown in FIG. It is no exaggeration to say that the accuracy of the inspection of concentricity, roundness, and cylindricity in the fixed state depends largely on the accuracy of the inspection, and it is no exaggeration to say that the accuracy of the cap depends on the accuracy of this inspection. .

In order to conduct such an inspection with high precision, it is necessary to ensure that the lower end 12 of the tube 1 is aligned with the introduction hole 3 as in the former conventional cap.
Even if it protrudes below the lower surface 13 of , or conversely, it is located inside the introduction hole 3, it is difficult to inspect. In order to conduct such an inspection with high precision, in FIG.
It is preferable that they are located within a range of 0.1 mm on the 8 side and 0.1 mm on the introduction hole 26 side, and more preferably that they are the same.

Therefore, in order to perform this inspection with high precision, the cap according to the present invention is suspended from the upper plate 20 with the tube 21 positioned in a highly concentric state with respect to the introduction hole 26 as shown in FIG. The lower end 30 is configured to be substantially flush with the lower surface 31 of the composite plate 23.

A method for manufacturing the base of the present invention in which the lower end 30 of the tube 21 is provided at a preferable position will be described with reference to FIG.

FIG. 2 is a longitudinal cross-sectional view showing a state in which the upper plate 20, pipe 21, intermediate plate 24, and composite plate 23 in FIG. , a pipe holding plate 34, and bolts 35, 36 constitute a jig 32.

First, place the introduction hole 2 on the tube centering plate 33.
6. A composite plate 2 in which bolt holes 37, fixing holes 38 for the tube 21, inflow holes 22 for the polymer B, etc. are pre-drilled.
3, the intermediate plate 24, and the upper plate 20 are placed in this order from below and fixed with bolts 36. Next, tube 21
are inserted into these members, and then sandwiched between the pipe holding plates 34 from the upper part of the pipe 21 and fixed with bolts 35.

At this time, a hole 39 having the same inner diameter as the outer diameter of the tube 21 is drilled on the upper surface of the tube centering plate 33 with a fitting accuracy of about an intermediate fit, so the lower end 30 of the tube 21 is inserted into this hole 39. By inserting and standing upright, it is possible to easily prevent bending, inclination, etc. that occur when the pipe is inserted between the pipe holding plates 34 and fixed with the bolts 35.

Next, the tube 21 and the upper plate 20 are fixed together to form an integrated unit. As a means for forming the integrated unit, various processing methods can be used, such as vacuum brazing, which involves heating and fusing the tube 21 and the upper plate 20 in a vacuum furnace using a metal brazing material, laser welding, crimping, and pressing.

After the tube 21 and the upper plate 20 are integrated, the tube holding plate 34 and the tube centering plate 33 are disassembled, and the tube 21
The part protruding from the top surface of the top plate 20 and the bottom surface 3
Cut off the part that sticks out from 1. Then, these both sides are finished with high precision so that they are the same surface. As a processing method for finishing on the same surface, it is preferable to select a processing method that does not apply external force as much as possible, such as liquid honing or electric field polishing.

By processing as described above, the concentricity between the tube 21, which is the inflow pipe for the A component polymer, and the introduction hole 26 for the B component polymer, which is bored in the composite plate 23, can be set with high precision. That is, tube 2
By making the lower end 30 of 1 and the lower surface 31 of the composite plate 23 on the same surface and processing the lower end 30 after the tube 21 and the upper plate 20 are integrated, it is possible to process the lower end 30 with high precision concentricity, and the tube 21 and the introduction It also becomes easier to inspect the concentricity with the hole 26. If both are eccentric, it can be repaired while magnifying it with a microscope or the like.

Note that even without using the jig 32 shown in FIG.
Although there is a processing method in which the lower end 30 of the tube is made to coincide with the lower surface 31 of the composite plate by using the thickness of the intermediate plate 24 or the composite plate 23 itself, this is not preferred for reasons of maintaining accuracy.

Next, the cap shown in Fig. 3 is made of polymers A, B, and C.
FIG. 2 is a longitudinal cross-sectional view of a cap according to the present invention having a three-layer composite structure consisting of three components.

The difference from the cap shown in FIG. 1 is that the caps shown in FIG. It communicates with the component polymer inflow hole 22, and in other respects there is no difference from the cap shown in FIG.

Here, polymer C, which is the outermost layer component, may be a different component from polymers A and B, or may be the same component as A or B.

If the cap has such a three-layer structure and the outermost polymer layer is made into a sheet as the protective layer C, the adjacent threads will be fused and bonded through this protective layer C, so that the core and sheath during fusion bonding will be bonded. This prevents eccentricity and deformation of the components, and when the sheet is torn and used separately, or when the ends of the sheet are divided into individual optical fibers and an attempt is made to tear them for connection, the protective layer C Since it can be torn at the fused bond, the core and sheath components will not be damaged.
A sheet with better translucency can be obtained.

Furthermore, although fluorine-based polymers are generally used as the sheath component polymer B, these polymers have low adhesive strength, and depending on the type, fusion bonding is often difficult. Even in such cases, the protective layer C
This problem can be easily solved by selecting a polymer with appropriate physical properties. Furthermore, since it becomes possible to reduce the amount of the generally expensive sheath component polymer B used and to form a thin film, it becomes possible to manufacture an inexpensive plastic sheet.

Note that the use of the jig 32 shown in FIG. 2 in manufacturing this cap is the same as in the case of the cap shown in FIG. 1.

At the bottom of the cap shown in FIGS. 1 and 3, there is a convergence guide that converges adjacent yarns in a row and fuses them together to form a sheet, a cooling device,
A winding machine etc. are provided.

[Function] According to the above-mentioned cap, the core component polymer A flowing from the tube 21 flows down inside each tube 21 and reaches the tube end 3.
It reaches near 0.

On the other hand, the sheath component polymer B flowing in from the inflow hole 22
passes through the distribution chamber 25, flows from the introduction hole 26 of each composite plate 23, and joins with the core component polymer A in the composite chamber 28, where a core-sheath composite flow is formed.

At this time, the tube 21 is attached to the upper plate 2 with high precision in concentricity, roundness, cylindricity, etc. with respect to the introduction hole 26.
Since the core component polymer A is suspended from zero, the core component polymer A flows into the composite chamber 28 in a state where there is no eccentricity with respect to the sheath component polymer B, that is, there is no thickness unevenness of the sheath component polymer B with respect to the core component A. In addition, in the complex room 28,
The adhesion between the core and sheath polymer components is further improved, and then the material is spun out from the discharge hole 29.

Further, since the spun yarns are arranged in rows with adjacent tubes 21 close to each other, the spun yarns are easily bundled with a guide or the like below the spinneret and fused and bonded into a sheet.

[Example] In the cap shown in FIG.
mm diameter discharge holes 29 are drilled in one row with an interval of 2.5 mm, the number of holes is 40, and the number of arrays is 1, and the inner diameter
FIG. 3 shows a pipe 21 with an inner diameter of 1 mm, an outer diameter of 2 mm, and a length of 30 mm, in which a 2.3 mm inlet 26 is bored corresponding to the position of the discharge hole, and is suspended from a 10 mm thick upper plate 20. Using a jig 32, its lower end 30 is attached to the composite plate 23.
The base of the present invention was formed to match the lower surface 31 of the base.

Then, polymethyl methacrylate was melt-spun as the core component polymer A, and vinylidene fluoride polymer as the sheath component polymer B, and these were melt-spun into this nozzle, and the fibers were focused and fused using a guide (not shown) provided below the nozzle, and spun 22.7 m/22.7 m/s. The film was taken up at 50 m/min, then stretched 2.2 times using a hot air circulation heater set at 150°C, and wound up on a winder at 50 m/min.

The sheet obtained here has a single yarn diameter of 250μ and a sheet width of 10mm±30μ, and a homogeneous sheet with no deformation, eccentricity between the core and sheath, unevenness in appearance, or bending of the individual single yarns. It was done.

The light transmittance of this fiber sheet was 250 dB/Km at a wavelength of 650 nm, and was of excellent quality with no practical problems.

[Effects of the invention] The invention can produce the excellent effects described below.

A The tubes 21 and the introduction holes 26 are arranged concentrically, and the lower end 30 of each tube 21 and the lower surface 31 of the composite plate 23 are made substantially the same surface, so that concentricity, roundness, and cylindrical It becomes possible to manufacture a cap with high accuracy such as degree, and it becomes possible to match the center of the tube 21 and the center of the introduction hole 26, that is, the concentricity between the two with high precision.

B Also, the pipe 2 is used as an inflow hole for the core component polymer A.
1 and arranged in a row, adjacent discharge holes 29 can be arranged extremely close to each other.

C Furthermore, a lower plate 27 is provided below the composite plate 23, corresponding to the introduction hole 26, and having a composite chamber 28 provided concentrically for each tube 21 and a discharge hole 29 communicating therewith, Since adjacent threads are focused by the focusing guide at the bottom of the cap, it is possible to collect a plurality of threads in a row and fuse them together while maintaining the concentricity of the core and sheath.

Therefore, the present invention has excellent quality in which the individual optical fibers are closely arranged in a row or in multiple rows without eccentricity between the core and sheath two components due to the effects A to C above. It is possible to produce a plastic sheet with a double core/sheath structure.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the plastic sheet manufacturing die according to the present invention, and FIG.
FIG. 1 is a longitudinal cross-sectional view of a jig for manufacturing a die shown in FIG. 1, and FIG. 3 is a longitudinal cross-sectional view of a die for manufacturing a plastic sheet according to the present invention in a different aspect from that shown in FIG. Furthermore, FIGS. 4 and 5 are longitudinal cross-sectional views of main parts of a conventionally known die for producing core-sheath composite fibers. Explanation of symbols in the drawings, 20...Top plate, 21...
Pipe, 22... Inflow hole, 23... Composite plate, 24...
Intermediate plate, 25...Distribution chamber, 26...Introduction hole, 27
... lower plate, 28 ... compound chamber, 29 ... discharge hole, 3
0...lower end, 31...bottom surface, 32...jig, A...
...core component polymer, B...sheath component polymer, C...protective layer component polymer.

Claims (1)

[Claims for Utility Model Registration] An upper plate 2 in which a plurality of tubes 21, which are inflow tubes for core component polymer A, are suspended in a row in close proximity, and at least one inflow hole 22 for sheath component polymer B is bored.
0 and a composite plate 23 arranged on the lower surface side of the upper plate 20.
A distribution chamber 25 for the sheath component polymer B that communicates with the inflow hole 22 is formed in the composite plate 23, and a chamber 25 that communicates with the distribution chamber 25 and is concentric with each of the plurality of tubes 21 is formed in the composite plate 23. placed, and
An introduction hole 26 having an inner diameter larger than the outer diameter of the tube 21 is bored, and a thread in which the core component polymer A and the sheath component polymer B are coated, which are discharged through the introduction hole 26, is inserted into the lower part of the mouthpiece. In a plastic sheet manufacturing die provided with a convergence guide for converging in rows to form a sheet, the lower end 30 of the tube 21 and the lower surface 31 of the composite plate 23 are arranged substantially on the same plane, and the composite Below the plate 23, a composite chamber 28 corresponding to the introduction hole 26 and concentrically provided for each tube 21, and a discharge hole 2 communicating with the composite chamber 28.
9. A plastic sheet manufacturing mouthpiece characterized in that it comprises a lower plate 27 on which 9 is formed.