JPH07103486B2 - Spinneret - Google Patents

Description

TECHNICAL FIELD The present invention relates to a spinneret for a spinning device for spinning synthetic fibers and the like.

[Prior Art] Conventionally, a spinneret used for melt-spinning synthetic fibers is installed at a spinneret inlet of a polymer inlet surface as disclosed in Japanese Utility Model Publication No. 51-24312 and Japanese Patent Publication No. 60-24844. Although a counterbore is formed, since the size of the counterbore is smaller than the space between the spinning holes, a horizontal plane is formed between adjacent counterbore. That is, FIGS. 2 (a) and 2 (b) show a cross-sectional view and a schematic plan view of a main part of such a spinneret,
In the figure, 1 is a spinneret main body, and the main body 1 is provided with a large number of spinning holes 2. Generally, as the number of single yarns increases, the spinning holes 2 are arranged in an even arrangement such that the number of yarns on the concentric circle increases to two or three. The spinning hole 2 is usually composed of a discharge hole 2a, an introduction hole 2b, and a spot facing portion 2c. The introduction hole 2b is provided immediately upstream (upper part) of the discharge hole 2a, and its upper end is spot facing or chamfered. It is part 2c. Horizontal planes 3 are formed between adjacent counterbore portions on the back surface of the spinneret in contact with the polymer.

On the other hand, FIGS. 3 (a), (b), and (c) show a cross-sectional view and a schematic plan view of the essential part of the improved spinneret already proposed by the present inventor, in contact with a polymer. Spinneret body
Circumferentially raised part 13a with a substantially triangular cross section on the back of 11
The circumferentially depressed portions 13b are arranged so as to be alternately formed with the circumferentially depressed portions 13b, and the spinning holes 2 are circumferentially arranged along the apex angle line 13b '.

[Problems to be Solved by the Invention] When melt spinning is carried out using a conventional spinneret as shown in FIG. 2, due to influx of molten polymer, temperature unevenness of inner and outer layers of the spinneret, etc. Discharge unevenness may occur and the variation between single yarns may increase, which may cause a malfunction in the yarn manufacturing process, and may also contribute to product quality variation.The melted polymer passed through the conduit and was measured by a metering pump. Later, studies have been conducted to reduce variations by strengthening filtration inside the pack, especially sand and filter reinforcement. This filtration enhancement enhances the trapping and crushing effect of the stayed substances and gel in the pack and allows the melted polymer to flow into the spinneret. However, even if the trapping and crushing effects are enhanced, denier unevenness between single yarns, process irregularities, etc. occur. This is because the polymer stays in the horizontal plane portion formed between the adjacent spot facing portions on the back surface of the spinneret, or the flow velocity becomes extremely slow and the residence time becomes long to cause thermal decomposition. This pyrolyzed polymer has a low melt viscosity, and a polymer with a low melt viscosity that was pyrolyzed during spinning is discharged from the hole in the spinneret at the same time as a polymer with a higher melt viscosity that is not pyrolyzed and is discharged. Has a major drawback that the component having a low melt viscosity bends in the flowing direction and comes into contact with the surface of the spinneret or adheres thereto or the size of the spun yarn becomes non-uniform. Further, there is a defect that colored yarn is generated by thermal decomposition. Such a problem is remarkable when the degree of polymerization is high as in the case of the polyester tire cord polymer, and even when the degree of polymerization is not so high, it often occurs when the spinneret diameter is large and high-speed spinning is performed.

In order to solve these problems, the improved spinneret of FIG. 3 previously proposed by the present inventor does not have a horizontal surface formed between adjacent counterbore portions on the back surface of the spinneret, so that the retention of the polymer does not occur. Although it was significantly suppressed, and therefore the thermal decomposition of the polymer was also suppressed, a large effect could be obtained, but the apex angle line 13b 'of the circumferentially depressed portion formed between the spot facing portions which are adjacent to each other in the circumferential direction. Even the polymer staying in the vicinity could not be suppressed and it was not perfect.

Therefore, an object of the present invention is to solve these remaining problems and to provide a spinneret capable of dramatically reducing denier unevenness between single yarns under various spinning conditions and further improving spinning improvement. It is a thing.

[Means for Solving the Problems] That is, according to the present invention, in a spinneret in which a large number of spinning holes are arranged on the entire surface of the spinneret or in the shape of a donut excluding the central part, the back surface of the spinneret in contact with the polymer has a substantially cross section Triangular circumferentially raised portions and circumferentially depressed portions are formed alternately so that the spinning holes are arranged circumferentially along the apex angle line of the circumferentially depressed portions. , A substantially conical counterbore portion is provided at the inlet of the spinning hole, and the diameter of the counterbore portion is equal to or larger than the arrangement pitch of the spinning holes arranged circumferentially, and each counterbore portion is a circle. A spinneret characterized by being in contact with or overlapping with counterbore portions which are adjacent in the circumferential direction.

The spinneret of the present invention is mainly used for producing synthetic fibers, and particularly applied to polyester and polyamide.
The material of this spinneret is stainless steel (SUS steel) which has been conventionally used, ceramic material as composite material and its composite heat resistant sintered body, SUS steel with Cr, Al ₂ O ₃ , T
Any of the spinnerets in which the entire spinneret is coated with iC, TiN or the like may be used.

EXAMPLES The present invention will be described below with reference to the drawings. Figure 1 (a),
(B) and (c) are a main part sectional view and a schematic plan view, respectively, showing a specific example of the present invention, and FIG. 1 (c) is a spinning process in which a large number of spinning holes are equally arranged in three rows on a concentric circumference. Plan view of the back of the base,
FIG. 1 (a) is an enlarged view of a partial cross section along the radius of FIG. 1 (c), and FIG. 1 (b) is along the concentric circumference in which the spinning holes of FIG. 1 (c) are equally arranged. It is an enlarged view of a partial cross section. In the figure, reference numeral 21 denotes a spinneret body having a large number of spinning holes 22 formed therein. The spinning hole 22 is composed of a discharge hole 22a, an introduction hole 22b, and a spot facing portion 22c, and the introduction hole 22b is provided immediately upstream (upper part) of the discharge hole 22a.
Is provided, and the upper end portion thereof is countersunk to form a spot facing portion 22c. In addition, the back surface of the base body 21 has a substantially triangular cross section and has a circumferentially raised portion 23a and a circumferentially depressed portion 23b.
Are alternately formed, and the spinning holes 22 are circumferentially arranged along the apex angle line (not shown in the figure) of the circumferentially depressed portion. A substantially conical counterbore 22c is provided at the inlet of the spinning hole 22, and the diameter of the counterbore 22c is larger than the arrangement pitch of the spinning holes 22 arranged in a circumferential shape. 22c is designed to overlap with the counterbored portions adjacent to each other in the circumferential direction, and the apex angle line of the circumferentially depressed portion does not exist as an entity, and a substantially horizontal plane is formed between the adjacent counterbored portions 22c. There is no part to form.

The counterbore angle α is generally 45 to 90 °, and therefore, it is preferable to set the ridge / depression plane crossing angle β to 90 ° to 150 °, which is larger than that. Also, the spot facing part 2
The diameter of 2c is compared with the arrangement pitch of the spinning holes 22 arranged in a circle.
The ratio of 1.0 to 1.3 times is preferable from the viewpoint of smooth inflow of polymer.

[Operation and Effect] In the present invention, the back surface of the spinneret in contact with the polymer is formed so that the circumferentially protruding portions and the circumferentially depressed portions are alternately formed in a substantially triangular cross-section. The depressions have spinning holes arranged in a circle along the apex line, and the diameter of the counterbore at the inlet of the spinning holes is larger than the pitch of the spinning holes arranged in a circle. Since the counterbore parts that overlap with each other overlap each other, there is no substantial horizontal plane between the spinneret entry account counterbore parts, and not only the polymer above the counterbore part but also the circumferential ridge on the back of the spinneret. The polymer above the recessed slope is always guided smoothly along the slope to each spot facing, so the inflow of the melted polymer is very uniform compared to the conventional spinneret, and the partial retention of the polymer is complete. Will be discharged The occurrence of denier unevenness of the spun yarn, the deterioration of quality due to the thermal decomposition of the polymer, and the process disorder are reduced. Particularly, the effect is remarkable when the degree of polymerization is high, such as a polymer for polyester tire cord.

[Brief description of drawings]

1 (a), 1 (b) and 1 (c) are cross-sectional views and a schematic plan view of a main part showing a specific example of the present invention, and FIGS. 2 (a) and 2 (b) are conventional spinnerets. FIG. 3 (a), FIG. 3 (b) and FIG. 3 (c) are a sectional view and a schematic plan view of an improved conventional spinneret. 22 ... Discharge hole, 22c ... Counterbore 23a ... Circumferential ridge, 23b ... Circumferential depression

Claims (1)

[Claims] 1. A spinneret in which a large number of spinning holes are arranged on the entire surface of a spinneret or on a donut surface excluding the central portion, and the backside of the spinneret in contact with a polymer has a substantially triangular cross section and is raised in a circumferential shape. And the circumferentially depressed portions are alternately formed, and the spinning holes are arranged circumferentially along the apex angle line of the circumferentially depressed portions, and a substantially conical shape is formed at the inlet of the spinning holes. -Shaped counterbore part is provided, and the diameter of the counterbore part is equal to or larger than the arrangement pitch of the spinning holes arranged circumferentially, and each counterbore part is adjacent to the counterbore part in the circumferential direction. A spinneret characterized by being in contact with each other or overlapping each other.