JP2001346463A - Biodegradable net for cultivating laver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a net for cultivating laver, good in attachment of seedlings of the laver by a normal cultivation method, hardly causing dropout thereof while raising the seedlings, hardly causing pollution even if the net is subjected to landfill disposal in the soil, or incineration disposal although the net for cultivating the laver is the one capable of resisting the use of two to three years and suitable for the cultivation of the laver, capable of exhibiting effects of soil activation and as a soil improver, and hardly giving bad effects on the ecosystem of marine organisms even if the net is floated in the sea by an unexpected accident. SOLUTION: This net for cultivating the laver is obtained by utilizing the good formability and crystallinity of a polylactic acid(PLA) obtained by hydrolyzing a starch [(C6H10O4)n] of a farm product such as a corn, subjecting the hydrolyzed product to lactic fermentation, further subjecting the fermented product to cyclization reaction, and melt-polymerizing the resultant lactide (C6H8O4), and knitting not only a yarn composed of the polylactic acid resin but also a net yarn (1) composed of plural strands (2) obtained by combining the whole or two kinds of a monofilament yarn (5), a multifilament yarn (4) and a spun yarn (3).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is suitable for cultivating laver, and has no adverse effect on the marine ecosystem even if it is released into the ocean due to an unexpected accident. The present invention relates to a biodegradable nori cultivation net having no effect.

[0002]

2. Description of the Related Art Regarding laver aquaculture nets, polyhydroxybutyl / variate (PHB) is required so that its disposal after practical use will not adversely affect the marine ecosystem and terrestrial living environment. / V), polycaprolactone (PCL), polybutylene succinate (PBS), and polybutylene succinate / adipate (PBSA).
The lack of thorough function as a laver seeding device derived from basic properties such as elongation, specific gravity, and water absorption-water retention has fatally hindered the completion of laver aquaculture nets.

[0003] Further, regarding the biodegradable function, the speed and degree of biodegradation by atmosphere have not been deeply studied,
It is a major problem that the most important practical period cannot be specified for industrial materials such as laver nets.

[0004] The present invention provides a high degree of polymerization (weight average molecular weight of 20).
10,000 ± 20,000) polylactic acid resin (PLA) is a hydrolysis-type biodegradable resin like the polybutylene succinate (PBS), but has good moldability and high crystallinity, It is possible to make up for the low water absorption of the water-soluble resin by changing the shape of the fiber in various ways, and the polylactic acid resin (PLA) with a high degree of polymerization has tensile strength, elongation, degree of orientation, and dyeing characteristics. Also, the present invention has been made with a view to providing effective physical properties under severe use conditions such as a fishing net.

That is, the present invention relates to a nori cultivation net suitable for cultivation of nori, which has good adhesion of nori sprouts by a normal cultivation method, does not fall off during seedling raising, and can withstand practical use for two to three years. Even if spilled into the ocean, it is easily biodegraded in a very short time compared to the semi-permanent period of conventional fossil fuel-based synthetic resin fiber nets, and does not adversely affect marine ecosystems Thing. Even when landfilled in the soil upon disposal, it can be biodegraded in a very short time and easily, exhibiting the effect of a soil conditioner that activates the soil, and in farmland, produce highly safe crops. And have no adverse effect on the surrounding living environment. 1 of fossil fuel-based synthetic resin fiber net even after incineration
Combustion heat of about / 3 does not damage the incinerator, and NOX and dioxin are not generated in the combustion gas. It is an object of the present invention to provide a biodegradable nori cultivation net which can solve the above problems.

[0006]

The biodegradable sea according to the present invention is provided.
Moss cultivation nets are made of starch (C ₆
H₁₀O₅)_nHydrolysis, then lactic acid fermentation,
Lactide (C₆H₈O₄) Melt polymerization
Molding of polylactic acid resin (PLA) with high degree of polymerization
It utilizes the property of crystallinity and high crystallinity.
In addition to using yarn made of resin (PLA),
Monofilament yarn, multifilament of lactic acid resin (PLA)
Lament yarns and spun yarns
Using a strand consisting of a plurality of strands
And it is knitted.
The strength, water retention and durability required for fishing nets.
The best biodegradable laver cultivation net
is there.

[0007]

According to the biodegradable laver cultivation net of the present invention, a monofilament yarn or a multifilament consisting of a polylactic acid resin (PLA) having a high degree of polymerization (hereinafter, simply referred to as a polylactic acid resin (PLA)). All or 2 of yarn and spun yarn
Since the seeds are combined into a strand and knitted using a mesh yarn consisting of a plurality of the strands, not only can good moldability and high crystallinity of the polylactic acid resin having a high molecular weight be utilized, but of course 2 to A remarkable effect is obtained that can be used as a laver culture net that can withstand three years of practical use.

Further, the above-mentioned polyhydroxybutyl / variate (PHB / V), polycaprolactone (PCL), polybutylene succinate (PBS), polybutylene succinate /
Sufficient strength required as a laver seeder, which cannot be obtained with biodegradable resins such as adipate (PBSA)
Water-absorbing-water-retaining and durable functions, and can secure a comparable harvest in comparison with the amount of nori harvest when using a nori cultivation net that does not use biodegradable resin thread. It can be.

[0009] That is, it is a necessary condition that the material fiber of the nori cultivation net has a tensile strength of at least 1.5 g / d, but polylactic acid resin (PLA) having a high degree of polymerization is
Monofilament yarn, multifilament yarn, in any form of spun yarn, has a tensile strength of 3 g / d or more, 1.0 g / d or less of the PHB / V, PCL, PBS, PBSA
Compared to 1.5 g / d, the tensile strength is much better, and the polylactic acid resin (PLA) is compatible with the PHB / V, PCL, PB
Like S and PBSA, it is a hydrolysis-type biodegradable resin, but because it has better moldability and high crystallinity than these, it is a fiber spun from polylactic acid resin (PLA) by melt spinning. The general fiber properties are almost equal to those of polyvinyl alcohol fiber (hereinafter referred to as vinylon fiber) and polyester fiber, which are frequently used as laver cultivation nets, in tensile strength, elongation, degree of orientation, and dyeing properties.
Young's modulus of about 1/2 of 400~600kg / mm ^2, the melting point is somewhat lower 175
℃, specific gravity of vinylon fiber 1.28, polyester fiber 1.
By setting 1.25 to 38, it is possible to provide effective physical properties under severe use conditions such as laver cultivation nets and fishing nets.

The fiber form of the polylactic acid resin (PLA) may be changed in various ways, for example, as described in claims 2 and 3, wherein the monofilament yarn or the multifilament yarn is
If the water absorption and / or water retention to provide water absorption and / or water retention is any one or a combination of foaming, U-shaped section, flat shape or a form in which inorganic fine pieces are mixed and spun, high water absorption and water retention can be obtained. This makes it possible to compensate for the low water absorption of the biodegradable resin which is equivalent to the defect as a laver seeding device, to improve the function as a laver seeding device, and to provide an optimal biodegradable laver cultivation net.

Further, when a plurality of monofilament yarns and spun yarns of polylactic acid resin (PLA) are used as a core, and a multifilament yarn is arranged on a surface portion to form a strand,
The effect of providing effective physical properties under severe use conditions of the laver cultivation net can be further improved.

Further, as described above, a plurality of monofilament yarns and spun yarns made of a polylactic acid resin fiber are used as a core, and a multifilament yarn is arranged on a surface portion to form a strand. By using a multifilament yarn made of polylactic acid resin fiber and a plurality of monofilament yarns as a core, and arranging a spun yarn on the surface to form a strand, the strength required as a laver cultivation net can be obtained. The yarn strength retention rate is about 92 to 95% with respect to the strength of an average seaweed cultivation net (a seaweed cultivation net made of vinylon fiber or polyester fiber, which is widely used as a seaweed cultivation net), and is 2 to 3%. It is possible to secure a practical period of one year.

Therefore, according to the biodegradable nori cultivation net of claim 1 according to the present invention and claims 2 to 4 for specifying the same, the adhesion of nori sprouts by a normal culture method is good,
A nori cultivation net suitable for the cultivation of nori that does not fall off during seedling raising and can withstand practical use for 2 to 3 years, and biodegrades in a very short time and easily even if it flows into the ocean due to an unexpected accident Even if it is landfilled in the soil for disposal, it will biodegrade easily and easily, even if it is landfilled, without detrimental effects on marine ecosystems. In that case, it is possible to produce highly safe crops, does not adversely affect the surrounding living environment, and even if incinerated, burns with 45 OO Cal / g of combustion heat and 1/3 of fossil fuel-based plastic It has the advantage of not damaging the furnace and can provide a seaweed cultivation net that does not generate NOX or dioxin in the combustion gas.

According to a fifth aspect of the present invention, the polylactic acid resin (PLA) contains natural fibers or a fossil fuel-based chemically synthesized resin.
By making the biodegradable laver cultivation net according to claim 1, 2 or 3 mixed and knitted with the same resin fiber, in the laver cultivation industry, as in the general fishing industry,
There is no habit of completely replacing new types of laver culture nets and related equipment, and they tend to stick to the technology and equipment until yesterday. It is one method to mix natural laver net material, which has the effect of making the new material polylactic acid resin familiar and also has the effect of reducing the amount of waste disposal by half.

[0015]

EXAMPLES The following Examples 1 to 5 are, as described above,
Corn produce (C ₆ H ₁₀ O ₅ ) _n
Utilizing the good moldability and high crystallinity of polylactic acid resin (PLA) obtained by subjecting lactide (C ₆ H ₈ O ₄ ) obtained by hydrolysis to lactic acid fermentation and cyclization reaction to melt polymerization. Then, by a melt spinning method, all or two of the monofilament yarn (5), the multifilament yarn (4), and the spun yarn (3) are combined into a strand (2). Biodegradable laver cultivation by frog or knitting using the twisted net yarn (1) or by knotless knitting using the two-twisted net yarn (1) consisting of two strands (2) It is made by knitting a net.

FIG. 1 is a cross-sectional view of a net yarn (1) and a strand (2) constituting a biodegradable laver cultivation net according to an embodiment, and FIG. 1 is a partially enlarged view of a monofilament. FIG. 2 is a schematic cross-sectional view of a three-wire twisted mesh yarn (1) composed of three strands, FIG. 2 is a schematic cross-sectional view of a two-wire twisted mesh yarn (1) composed of two strands (2), and FIG. FIG. 4 is a schematic perspective view of a monofilament having a U section, FIG. 5 is a schematic perspective view of a monofilament in which mica having hygroscopicity is mixed, and FIG. 6 is a schematic perspective view of a flat monofilament. is there.

Embodiments 1 to 5 described below.
As a conventional seaweed cultivation net for comparison with the biodegradable seaweed cultivation net according to the present invention, a net of a body net (vinylon spun yarn 20s / 10,
Nori cultivation net 18 with a general configuration of vinylon monofilament yarn 500d / 6, nylon filament yarn 840d / 2) x 3
The fabric is knitted by a frog or knitting method, and this is referred to as "conventional laver cultivation net".

(Example 1) A biodegradable laver cultivation net according to Example 1 of the present invention is a spun yarn made of polylactic acid resin of 10 s / 5.
(3) A three-strand consisting of four (4) multifilament yarns (4) made of polylactic acid resin of 500d / 60F × 6 and a monofilament yarn (5) of polylactic acid resin of 500d.
The body net is knitted by a frog or knitting net method using the twisted net yarn (1), and the mesh is 300 mm, the hook is 7.5, the length is 92.5, the net width is 1.6 m
× The net length was 19.5 m, and the 18th net was referred to as “First Example Net” according to Example 1 of the present invention.

As shown in FIG. 1, the cross section of the mesh yarn (1) is composed of four monofilament yarns (5), which are surrounded by multifilament yarns (4) to form a core. And a strand (2) in which a spun yarn (3) is arranged on the surface of the periphery of the strand (2), and the lower twist is a tight triple twist.

(Embodiment 2) Although Embodiment 2 is not shown,
Four 500d monofilament yarns (5) are arranged around a 10s / 5 polylactic acid resin spun yarn (3) to form a core, and the same multifilament yarn of 500d / 60F / 9 is placed on the surrounding surface.
(3) Strand (2) composed of three strands (1), consisting of three strands (2). 92.5 eyes, net width
The seaweed cultivation net is knitted and tailored to 1.6m x 19.5m net length, and 18
On the other hand, the second embodiment network according to the second embodiment of the present invention is referred to as “second embodiment network”, and the reference numerals in the description are the same as those in the first embodiment.

(Embodiment 3) In Embodiment 3, a net of a body net (1)
To a 10s / 8 polylactic acid resin spun yarn (3), 500d / 60F /
A double-twisted net yarn (1a) consisting of two strands (2) provided with nine polyfilament resin monofilament yarns (5) of the same multifilament yarn (4) × 6, 500d of 9 By the knotless knitting method, a mesh of 300 mm, a seam of 7.5 and a length of 92.5 are tailored to a net width of 1.6 m × net length of 19.5 m, and a net width of 1.6 m × net length of 1
The seaweed cultivation net was knitted and knitted at 9.5 m to obtain a "third embodiment net" according to the third embodiment of the present invention.

As shown in FIG. 2, the structure of the mesh yarn (1a) is as follows: a spun yarn (3) at the center, six monofilament yarns (5) around it, and a multifilament yarn (5) around its periphery. 2 consisting of two strands (2) with (4)
It is a child twist.

Example 4 In Example 4, a 10s / 8 polylactic acid resin-made spun yarn (3) was used for the core, and 500d so as to cover it.
A double-twisted mesh yarn consisting of two monofilament yarns (5) made of polylactic acid resin, and a strand (2) having the same multifilament yarn (4) of 500d / 60F / 9 on the outer skin portion ( 1a)
With a knotless knitting method, a mesh size of 300 mm and a stitch 7.
5. Nail length of 92.5 is tailored to net width 1.6m x net length 19.5m, tailored to net width 1.6m x net length 19.5m, knitting nori cultivation net,
The “fourth embodiment network” according to the third embodiment of the present invention,
The same reference numerals in the description denote the same parts as in the third embodiment.

Example 5 In Example 5, polylactic acid resin fibers were modified by a general method of changing the shape of the nozzle.
100-200μ diameter filament with open-cell foam
(6) Using the monofilament yarn (5a) on which (see FIG. 3) was formed, using a frog or knitting method as in Example 1, a mesh length of 300 m was used.
m, 7.5 stitches, 92.5 stitches, net width 1.6m x net length 19.5m
And a knitted seaweed culture net was knitted to form a "fifth embodiment net" according to the fifth embodiment of the present invention.

Example 6 In Example 6, polylactic acid resin fibers were formed by a general method of changing the shape of the nozzle.
Example 1 Using a monofilament yarn (5b) having a U-shaped filament (7) (see FIG. 4) with a filament having a diameter of 100 to 200 μm,
This is a “sixth embodiment network” according to the sixth embodiment having the same configuration as that of the sixth embodiment.

The monofilament yarns (5a) and (5b) having the foamed structure of Example 5 and the U-shaped structure of Example 6 were prepared by adding 5% by weight of sodium bicarbonate or organic compound to polylactic acid resin (PLA). It is obtained by uniformly mixing 4% of a foaming agent such as azone carboxamide (ADCA) and spinning at a nozzle temperature of 160 to 163 ° C. and a draw ratio of 8 to 6.

(Example 7) In Example 7, a monofilament yarn (5) was treated with mica (diameter: 0.2-1.0 μm, length: 20 μm) which was an inorganic fine piece (8) having water absorbency in polylactic acid resin (PLA). ~ 30μ
) Is mixed and spun into a 500d polylactic acid resin monofilament yarn (5c) (see FIG. 5), and four of the monofilament yarns (5c) are made of a polylactic acid resin fiber of 500d / 6
A core surrounded by a multifilament yarn (4) of 0F × 6,
Using three strands (1) (see Fig. 1), three strands (2) with a spun yarn (3) arranged on the surrounding surface, and three strands with a tight bottom twist The body net is knitted by the knitting net method.
Embodiment 7 of the present invention tailored to 1.6 m × 19.5 m net length and 18 counters
Of the seventh embodiment.

Using the “first embodiment net” to “seventh embodiment net” and the “conventional laver cultivation net” according to each of the first to seventh embodiments described above, on October 10, 1999, outdoor harvesting was performed. Although seeding was carried out by the seedling method, seawater temperature was rather high and implantation was insufficient.
On October 20, the second seeding was carried out, and the implantation per field of view of each net was confirmed with a 100 × microscope. All of the “First Example Net” to “Seventh Example Net” , 100-150 implantations per field of view, comparable to "conventional laver culture nets"
Confirmed the number.

Next, healthy nori seedlings were grown on each net by raising the seedlings until November 15 of the same year.
-9 each of "7th embodiment net" and "conventional laver cultivation net"
The cultivation was started by arranging the anti at the pole type fishing ground and the solid fishing ground, respectively, and the remaining 9 antis were prepared for the overhang after the new year,
Stored in a refrigerator at minus 25 ° C.

By February 15, 2000, an average of 3,000 sheet laver was produced from each net of the pole fishing ground and the solid fishing ground. This harvest was the standard result of the year, and there was almost no difference in the production of each net.

The retention of net yarn strength of each net was about 93% on average, with the net yarn strength retention before seeding by the outdoor seedling method being 100.

In each of the nets of the first to seventh embodiments, the degree of biodegradation was extremely small since no nori buds fell off due to biodegradation of the fiber surface. Was considered.

On the other hand, nets destined for each of the nine nets of the first embodiment net to the seventh embodiment net stored in the refrigerator and the conventional seaweed aquaculture net were delivered on December 8, 1999, Nori production started at a pole fishing ground.

As a result, although the growth of the laver is good under the influence of the warm winter, the reddish-like pathological condition is the laver culture net of the "first embodiment net" to the "seventh embodiment net" and the "conventional laver culture net". By March 10, 2000, the “First Example Net” to the “Seventh Example Net” produced an average of 2600 sheets, and the “conventional laver aquaculture net” produced an average of 2800 sheets. This production was lower than the case where it was not stored in the refrigerator, but was within the range of the standard production at the local fishing ground.

When the refrigerator storage net is used, the net yarn strength retention of each net is 89.6% to 8
9.9%. This result is within the expected decline rate and is expected to be practical for next year and next year.

The speed of biodegradation during refrigeration is considered to be negligible, since the weight loss at the time of entry and exit was almost unmeasurable.

The biodegradable function of the laver net yarn by the polylactic acid resin fiber is the same as that when various types of fibers are individually drooped in water. Observed.

Accordingly, in terms of the function of the laver seeder, it is an absolute condition that the fiber has an appropriate level of water absorption or hydration. However, a 10s spun yarn of polylactic acid resin fiber is said to be the most excellent laver seeder. The water retention was almost the same as that of 20s spun yarn of vinylon resin fiber, and it was clear that it could compensate for the physical property of zero water absorption.

In addition, the water retention capacity of the laver net yarn required for drying in the laver fishing ground of either the prop fishing ground or the solid fishing ground is
The monofilament yarn (5) is not necessarily used in the core even if it is a three- or two-ply twist made of a polylactic acid resin (PLA) mono-filament yarn, multi-filament yarn, or a combination of all or two types of spun yarn. Because it is not fixed but appears on the surface, 5OOd / 60F multifilament yarn (4) of polylactic acid resin fiber and 10s spun yarn
(3) As a core, it can be predicted that it can be sufficiently retained by using a strand having a monofilament yarn (5) such as the same 500d on the surface, so that it can be predicted that it can be selectively used by laver fishing grounds. is there.

Furthermore, the biodegradable function of polylactic acid resin is 8
In the underwater drooping test or underground burial test for 5 months, the weight retention rate and the tensile strength retention rate were about 80%, but after about 12 months, both the weight retention rate and the tensile strength retention rate suddenly decreased. Almost disappears and decomposes in effect to change to oligolactic acid.

On the other hand, the seaweed cultivation period is about seven months from late September to late March, but due to technological innovations such as freezing methods, the time during which the seaweed cultivation net is in seawater is limited to one fishing season. The seaweed cultivation net made of polylactic acid resin, which can withstand practical use for two to three years, has been proved to be feasible because it takes about three months including the seaweed seeding, the seedling raising period, and the growing period.

In addition, the observation of the speed of biodegradation during refrigeration, the biodegradability of laver net yarn by the polylactic acid resin fiber, and the observation of interruption of biodegradation by refrigeration are the same as in Example 1. High water retention was obtained, especially by using foamed yarns or U-section yarns.

Further, in the case of Example 7, the adhesion of nori sprout by the ordinary culture method was more excellent than that of the other Examples 1 to 6, and there was no falling off during the seedling raising, and the optimum biodegradation was achieved. It has been found that it is possible to provide a nori cultivation net.
This suggests that the same effect can be obtained by mixing inorganic fine particles (8) having hygroscopicity, for example, silica (about 0.2 to 1.0 μ in diameter and about 20 to 30 μ in length).

In the above "First Example Net" to "Seventh Example Net", the monofilament yarn (5) or the multifilament yarn (4) absorbs and retains water in the form of foam, U-section, flat shape or Strands made by mixing inorganic fine flakes (2)
300 knots, 7.5 stitches, 92.5 stitches, with a knot knitting method, using a two-ply twisted net yarn (1a) consisting of two strands, with a net width of 1.6 m × net length of 19.5 m It does not include the case where the seaweed cultivation net is made and knitted by tailoring it to a net width of 1.6 m × net length of 19.5 m, and these have not been confirmed at any of the strut fishing grounds and the solid fishing grounds at any of the seaweed fishing grounds, The same results were obtained from the progress and results of cultivation at any of the strut fishing grounds and solid fishing grounds at the laver fishing grounds for the “first embodiment net” to “seventh embodiment net”, and the same results were obtained. I was convinced that this would be achieved.

This is because the monofilament yarn (5) or the multifilament yarn (4) absorbs and retains water, which is not described in the first embodiment net or the seventh embodiment net, in a flat or inorganic form. A three- or two-ply twisted mesh yarn made into strands (2) in the form of spun silica mixed as fine pieces (8)
The same applies to (1).

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a three-ply twisted mesh yarn.

FIG. 2 is a schematic sectional view of a two-ply twisted mesh yarn.

FIG. 3 is a schematic perspective view of a foamed monofilament.

FIG. 4 is a schematic perspective view of a monofilament having a U section.

FIG. 5 is a schematic perspective view of a monofilament mixed with mica.

FIG. 6 is a schematic perspective view of a flat monofilament.

[Explanation of symbols]

 (1) Mesh yarn (1a) Mesh yarn (2) Strand (3) Spun yarn (4) Multifilament yarn (5) Monofilament yarn (5a) Monofilament yarn of foam configuration (5b) Monofilament yarn of U cross-section configuration (5c ) Monofilament yarn mixed with mica (6) Foamed part (7) U-section (8) Fine inorganic particles

Continued on the front page F term (reference) 2B026 AA01 AB01 AC03 JA02 JA03 JA06 JC02 4L036 MA05 MA08 MA33 MA34 MA35 PA21 PA46 RA25 UA25 4L046 AA15 AA24 BA00 BB01

Claims (5)

[Claims] 1. A strand formed by combining all or two of monofilament yarn, multifilament yarn, and spun yarn of polylactic acid resin (PLA) having a high degree of polymerization into a strand, and manufactured using a mesh yarn comprising a plurality of the strands. Knitted biodegradable laver culture net. 2. A monofilament or multifilament yarn having a water absorption and / or water retention property.
The biodegradable laver cultivation net according to claim 1, which is in a water retention form. 3. The biodegradable laver according to claim 2, wherein the form of water absorption and water retention by the monofilament yarn or the multifilament yarn is any one or a combination of foaming, U cross section, flat shape, and spun mixed with inorganic fine pieces. Culture net. 4. The three-twisted or two-twisted net yarn, wherein a plurality of monofilament yarns and / or spun yarns are used as a core and a multifilament yarn is arranged on the surface to form a strand. 3. The biodegradable laver culture net according to 3. 5. A yarn in which the strand is made of polylactic acid resin (PLA), one or three kinds of natural fibers, fossil fuel synthetic resin, fibers made of fossil fuel resin, and biodegradable resin fibers other than polylactic acid resin. 4. The method according to claim 1, wherein
Or the biodegradable laver culture net according to 4.