JPH04335835A - Laver net - Google Patents

Abstract

PURPOSE:To provide the subject laver net excellent in resistance to strength reduction, dimensional stability, laver spore collection properties and growing properties of laver and capable of collecting a high-quality laver. CONSTITUTION:The subject laver net is characterized in that a filament constituting a laver net is composed of a composite yarn obtained by blending a polyester multi-filament with a vinylon multi-filament; and a single yarn constituting the above-mentioned polyester multi-filament has a modified cross section containing one or more depressed parts on the cross section and the area of the above-mentioned depressed parts is 10%-40% based on the sectional area of the single yarn.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a seaweed net, and more specifically, it is a seaweed net that is knitted from a composite yarn made by mixing and twisting irregular cross-section polyester filaments and vinylon yarn, which improves water retention and helps the growth of seaweed. Both relate to seaweed nets with excellent dimensional stability and durability.

0002

BACKGROUND OF THE INVENTION Conventionally, vinylon thread has been mainly used for seaweed nets because of its excellent ability to collect seaweed seedlings and grow them. Vinylon yarn has good water retention properties, making it an excellent fiber for seaweed netting. However, in order to obtain high-quality seaweed, it is necessary to dry the seaweed appropriately during its growth, and in particular, when culturing in areas with little tidal difference, the seaweed net needs to dry to some extent during the short period of time after the tide is low. However, vinylon thread was inferior in this respect, and not only was it impossible to collect high-quality seaweed, but it also had a large impact on the growth of seaweed.

An attempt to improve this point is known, for example, from Japanese Utility Model Publication No. 17751/1983. This publication teaches a seaweed net made of vinylon yarns and polyethylene yarns or polypropylene yarns arranged in every other row. Although this seaweed net is excellent in terms of the growth of seaweed, it has the disadvantage that the polyethylene threads or polypropylene threads are hydrophobic, making it difficult for seaweed to adhere to these parts, resulting in a large amount of waste as a seaweed net.

Furthermore, although vinylon filaments have excellent yarn properties in a dry state, when soaked in seawater, the physical properties of the fibers constituting the seaweed net decrease, making it particularly important as a net fabric. It has strong strength, large changes in elongation, and poor dimensional stability. A decrease in strength will lead to the net breaking, while a change in elongation will affect the bending of the net, and the large time difference between being located in the sea and on the sea due to the ebb and flow of the tide will cause uneven growth of seaweed, resulting in uneven growth of the seaweed. The quality of the seaweed that is harvested will deteriorate. In particular, there are cases where the net is not on the seawater even when the tide goes out, and in this case, there are parts of the seaweed net that cannot dry at all, which has a negative impact on the growth of the seaweed, making it impossible to obtain high-quality seaweed. .

Efforts to improve this point are known, for example, from Japanese Utility Model Application Laid-open No. 10753/1983. This publication teaches a method of obtaining a seaweed net using a mixed yarn of vinylon yarn and polyester multifilament. According to this method, a seaweed net with superior dimensional stability and strength can be obtained than when vinylon yarn is used alone. However, by mixing and twisting polyester monofilaments, the moisture in the net fabric dries quickly, and the moisture content of the net fabric becomes too small at low tide, which impedes the growth of nori and makes it impossible to obtain high-quality nori. It is necessary to control the moisture content depending on the installation location. However, this control is virtually impossible;
The twisting ratio of the polyester monofilament had to be lowered, and the smaller the twisting ratio, the less the desired dimensional stability and strength of the seaweed net could be obtained, which caused the net to bend, resulting in damage to the sea due to the ebb and flow of the tide. Due to the time difference in position at sea, patches of seaweed growth occur.

[0006]

[Problems to be Solved by the Invention] It is an object of the present invention to solve the above-mentioned conventional problems, to produce seaweed that grows well, to obtain high-quality seaweed, and to have excellent both dimensional stability and durability. Our goal is to provide seaweed nets.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the seaweed net of the present invention is provided, in which the filaments forming the seaweed net are made of a composite yarn in which polyester multifilament and vinylon yarn are mixed and twisted, and The single yarn forming the multifilament has an irregular cross section having at least one recess in the cross section, and the area of the recess is 10% to 40% of the cross-sectional area of the single yarn.

[0008]

[Embodiment] In the polyester filaments constituting the seaweed net of the present invention, it is essential that 80% or more of the polyester repeating units be ethylene terephthalate, preferably 90% or more, and more preferably 95%. Furthermore, conventionally known acid components and glycol components may be copolymerized within a range that does not impair the constituent elements and objects of the present invention. Examples of the copolymerized acid component include isophthalic acid and adipic acid. Further, examples of the copolymerized glycol component include tetramethylene glycol, 1,4 cyclohexanedimethanol, polyethylene glycol, and the like.

[0009] The polyester filament used in the present invention can be obtained by a conventional spinning method. That is, polyester chips are melted and spun through a spinneret hole having a C-shape, for example, at a speed of 600 m/min to 800 m/min, with a total fineness of 2000 denier to 6000 denier, and the spun yarn is cooled with cold air. After being solidified, the material is coated with an oil and then taken off by a take-off roll that controls the spinning speed. The taken-off undrawn yarn is usually drawn without being wound up. Of course, the undrawn yarn may be wound up and then stretched.

Specifically, the undrawn yarn has a continuous length of 180 mm.
It is hot-stretched at a temperature of .degree. C. or higher, preferably 200.degree. C. or higher. Stretching is performed in two or more stages, and the stretching ratio is in the range of 3.5 times to 6.0 times.

[0011] The proportion occupied by the concave portions of the irregular cross-section polyester filament is 10% of the area of the fiber portion other than the concave portions.
40%. If the area of the recesses is less than 10%, polyester is hydrophobic, so the moisture dries up completely at low tide, making it impossible to retain the moisture necessary for nori growth, resulting in stagnation of nori growth.

On the other hand, if the area of the concave portion exceeds 40%, the strength of the irregular cross-section polyester filament decreases, making it impossible to improve the dimensional stability and durability of the mesh fabric. At least one concave portion is required, and there may be more than one concave portion, but in order to satisfy the moldability of the spinneret or the strength properties of the obtained irregular cross-section polyester filament, the number of concave portions should be 4 or less. The specific shape is preferably a C-shape, a U-shape, a V-shape, a Y-shape, a W-shape, or an X-shape, and among them, there are 1 to 3 recesses in a C-shape, U-shape, V-shape, or Y-shape. is most preferable.

[0013] In the present invention, the recess area means the total area of the recess defined by the outer tangents of both adjacent convex parts across the recess.

The irregular cross-section polyester filaments and vinylon yarn thus obtained are twisted in a conventional manner so that the irregular cross-section polyester has a fineness ratio of 20% to 80% to obtain a composite yarn of the polyester filament and vinylon yarn.

If the proportion of polyester filaments of irregular cross section is less than 20%, not only will the strength of the net be insufficient and a durable seaweed net will not be obtained, but also the seaweed net will bend at low tide due to poor dimensional stability. There are parts of the seaweed net that are not exposed from the seawater, and the drying of the net in these parts is insufficient, which adversely affects the growth of the seaweed, and it is not possible to produce uniform seaweed throughout the seaweed net.

[0016] In addition, when the proportion of polyester filaments with irregular cross sections is 80% or more, the dimensional stability and durability of the seaweed net are satisfied, but since the polyester filaments are hydrophobic, it is difficult to use polyester with irregular cross sections. However, because the seaweed cannot maintain adequate moisture during low tide, the growth of seaweed is poor, and it is not possible to obtain high-quality seaweed.

In the present invention, both filament and spun yarns can be used as the vinylon yarn.

[0018]

[Examples] The present invention will be explained in more detail below with reference to Examples.

Examples 1 to 3 Polyethylene terephthalate having an intrinsic viscosity of 1.30 was melted in a 70φ extruder type spinning machine and spun using a spinneret having a C-shaped spinneret hole. The spun yarn was cooled by blowing cold air at 25° C. under the spinneret at a chimney wind speed of 40 m/min. Next, an oil agent was applied and a 5% pre-stretch was applied using four rollers, followed by stretching 3.0 times in the first stage and 2.0 times in the second stage. Each roller temperature is 60℃, 100℃, 120℃, 220℃
It is ℃.

[0020] The polyester filament having the concave shape thus obtained and the vinylon spun yarn were twisted with a twist coefficient of 18.
The fibers were twisted to have a density of 00 to 2,000 to obtain a composite yarn of 15,000 denier. The obtained composite yarn was knitted, and then seaweed spores were collected in a conventional manner and used for growing seaweed. Table 1 shows the characteristics of the obtained seaweed net and the growth results of the seaweed.

[0021]

[Table 1]

Item Unit Example 1 Example 2 Example 3
Wet strength g/d 3.5
5.5 3.2 Wet knot strength g/d 1.8
2.5 1.8 Spore collection property
Good
Good Good Nori growth performance
Good Good Good Concave area
%20
20 40 Polyester blending ratio %
20 80 2
0 Comparative Examples 1 to 3 In melt-spinning polyester in the same manner as in Examples, Comparative Example 1 contained polyester filaments of irregular cross section obtained under the same spinning conditions as in Example 1 at a blending ratio of 10%. In Comparative Example 2, the degree of deformation of the C-shaped cap was changed to make the concave area 5%, and the blending ratio of polyester filament was 20%.
It was the same as Example 1 except that it was set as %. Comparative Example 3 was the same as Example 1 except that the blending ratio of polyester filaments was 90%. The results are shown in Table 2.

[0023]

[Table 2]

Item Unit Comparative example 1 Comparative example 2 Comparative example 3
Wet strength g/d 2.8
4.0 2.5 Wet knot strength g/d 1.6
1.9 2.7 Spore collection property
Good
Good Bad Nori growth performance
Bad Somewhat bad Bad Concave area
%20
5 20 Polyester blending ratio %
10 20 9
0 Comparative Examples 4 and 5 Comparative Example 4 is a seaweed net made of 100% vinylon spun yarn, and Comparative Example 5 is a seaweed net made of polyester filament having a normal circular cross section. Table 3 shows the results of evaluating each of these.

[0025]

[Table 3]

Item Unit Comparative example 4 Comparative example 5 Wet strength
g/d 2.7 3.8
Wet knot strength g/d 1.5
1.9 Spore collection properties
Good Bad Nori growth quality Good
Bad recess area %
0 0
Polyester blending ratio %
0 20 As shown in Examples 1 to 3 above, the seaweed net according to the present invention has improved net strength in wet conditions and is highly durable compared to the seaweed net using vinylon spun yarn. The growth of seaweed was good due to its dimensional stability when wet. On the other hand, as shown in Comparative Example 5, when a polyester filament with a circular cross section was used, water retention was poor, leading to poor seaweed growth and poor seedling collection. As shown in the above Examples and Comparative Examples, it can be seen that the optimal blending ratio of the polyester filament with irregular cross section and the vinylon spun yarn is 20% to 80%. In areas outside of this ratio, the strength of the netting may be insufficient, and the seedling productivity and growth of seaweed may be poor.

[0027]

[Effects of the Invention] The seaweed net according to the present invention has excellent dimensional stability without loss of strength, has little difference in time between being located in the sea and on the sea due to the ebb and flow of the tide, and has good growth when collecting seaweed seedlings. Furthermore, there are fewer spots on the seaweed, making it possible to harvest high-quality seaweed.

Claims (2)

[Claims] Claim 1: In a seaweed net, the filaments forming the seaweed net are made of a composite yarn in which polyester multifilament and vinylon yarn are mixed and twisted, and the single yarn forming the polyester multifilament has at least one recess in its cross section. 1. A seaweed net having a uniquely irregular cross section, wherein the area of the recess is 10% to 40% of the cross-sectional area of a single yarn. 2. The seaweed net according to claim 1, wherein the polyester multifilament and vinylon yarn are mixed and twisted in a composite yarn in which the polyester multifilament has a fineness ratio of 20% to 80%.