JP3906349B2 - Biodegradable composite monofilament and its use - Google Patents

Description

表１の結果から明らかなように、融点が７０℃以上であるポリブチレンサクシネート、ポリエチレンサクシネート、およびポリブチレン（サクシネート／アジペート）から選ばれた少なくとも一種を芯成分とし、ポリ乳酸およびそれの共重合ポリマー、ポリ（β−ヒドロキシアルカノエート）類から選ばれた少なくとも一種を鞘成分とし、芯成分と鞘成分の重量比が９５／５〜４０／６０の範囲にある本発明のモノフィラメント（実施例１〜３）は、繊維としての優れた力学的性能と生分解性を兼ね備えたものであり、生分解性モノフィラメントとしての要求性能を理想的に満たすものである。
【００５６】
また、この生分解性複合モノフィラメントを実際に釣糸として使用した場合には、使用後のチヂレもほとんどなく、釣糸としてきわめて良好であった。
【００５７】
一方、ポリブチレンサクシネート、ポリ乳酸、ポリ（β−ヒドロキシアルカノエート）類をそれぞれ単独に用いたモノフィラメント（比較例１〜３）、およびポリ乳酸およびそれの共重合ポリマー、ポリ（β−ヒドロキシアルカノエート）類から選ばれた少なくとも一種を芯成分とし、融点が７０℃以上であるポリアルキレンジカルボキシレート類を鞘成分とした、本発明とは芯／鞘成分を逆転した複合モノフィラメント（比較例４、５）は、強度、耐摩耗性、耐疲労性、生分解性のいずれかが劣り、水産資材用途における要求性能を満足するものではなかった。
【００５８】
また、芯成分／鞘成分の重量比が９５／５〜４０／６０の範囲から外れた複合モノフィラメント（比較例６、７）は、本発明が目的とする効果を充分に満たすものではなかった。
【００５９】
【発明の効果】
以上説明したように、本発明の生分解性複合モノフィラメントは、繊維としての力学的性能および生分解性が均衡に優れていることから、環境、自然保護の両面から改善が強く望まれている各種産業資材用途、中でも水産資材用途、取り分け釣糸用途のモノフィラメントとしての要求性能を十分に満たすものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a monofilament excellent in balance between biodegradability and mechanical properties, and a marine material made of this monofilament, particularly a fishing line.
[0002]
[Prior art]
Conventionally, synthetic resins such as polyamide, polyester, polyolefin, and polyvinylidene fluoride have been mainly used as monofilament materials used for fishery materials such as fishing lines because of their mechanical requirements.
[0003]
However, monofilaments for marine materials made of these synthetic resins are hardly decomposed in a natural environment, so if they are discarded after use or left as they are, they will remain semi-permanently in the natural environment. It was a big hygiene problem.
[0004]
More specifically, there are frequent situations where discarded discarded fishing lines are planted on the seabed, and these discarded fishing lines or cut fishing lines are entangled with birds and marine life and killed. The improvement was strongly desired from both aspects of nature conservation.
[0005]
Therefore, in recent years, the development of fishery materials such as fishing lines, fishing nets, laver nets, etc. that are biodegraded by natural fungi and microorganisms after practical use, or biodegradable fibers used for various industrial materials has become active. Yes.
[0006]
The biodegradable polymer constituting the biodegradable fiber includes polyalkylene succinates typified by polybutylene succinate and poly (β-hydroxyalkanoates) typified by poly-3-hydroxybutyrate. , Polylactic acid, polyglycolic acid, and poly-ε-caprolactone are known, but it is difficult to satisfy both biodegradability and mechanical performance as a fiber with each polymer alone. Recently, a fiber composited by combining different types of polymers has been studied. Specifically, (A) a core-sheath composite fiber in which a high melting point polymer and a low melting point polymer are combined (JP-A-6-207324) JP, 6-248516, A), (B) The easy decomposition which has a deterioration rate more than twice as much as a sheath part as a highly degradable polyester and a core part from a sheath part Core-sheath composite fiber (Japanese Patent Laid-Open No. 7-305234) used as a conductive polyester, and (C) polyhydroxyalkanoate or a copolymer thereof as a core component, and polysulphide such as polyethylene succinate or polybutylene succinate as a sheath component A core-sheath composite fiber (Japanese Unexamined Patent Publication No. 7-324227) using an alkylene dicarboxylate has already been proposed.
[0007]
However, the core-sheath composite fiber (A) above is one that places importance on biodegradability and thermal adhesiveness, and is unsatisfactory in mechanical performance as a fiber used for marine products or various industrial materials. there were.
[0008]
Further, the core-sheath composite fibers (B) and (C) described above are intended to control the biodegradation rate, and it is difficult to say that they satisfy the sufficient mechanical performance. It was.
[0009]
Therefore, none of the conventional biodegradable composite fibers have sufficient mechanical performance as fibers and particularly sufficient biodegradation performance for marine products, and improvements are desired. It was real.
[0010]
[Problems to be solved by the invention]
The present invention has been achieved as a result of examining the solution of the problems in the above-described prior art as an object.
[0011]
Accordingly, an object of the present invention is to provide a monofilament having excellent balance of biodegradability and mechanical properties as a fiber used for marine materials or various industrial materials, and a marine material made of this monofilament, particularly a fishing line. It is in.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the biodegradable composite monofilament of the present invention comprises at least one selected from polybutylene succinate, polyethylene succinate and polybutylene (succinate / adipate) having a melting point of 70 ° C. or more. As a component, the sheath component is at least one selected from polylactic acid, a copolymer of polylactic acid, and poly (β-hydroxyalkanoate), and the weight ratio of the core component / sheath component is It is in the range of 95/5 to 40/60.
[0013]
In addition, the biodegradable monofilament of the present invention is suitable for various marine materials, in particular, fishing line applications. Among them, the fishing line comprising the biodegradable monofilament of the present invention has an excellent biodegradability and a tensile strength of 4.0 g. / D or more and excellent mechanical properties of nodule strength of 3.0 g / d or more.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
[0015]
A core component of a biodegradable composite monofilament of the present invention, in combination singly or two or among melting der is 70 ° C. or higher Lupo polybutylene succinate, polyethylene succinate, and polybutylene (succinate / adipate) And blended are used.
[0016]
The polylactic acid constituting the sheath component of the biodegradable composite monofilament of the present invention is poly-L-lactic acid and / or poly-D-lactic acid, and the polylactic acid copolymer is L-lactic acid / D-lactic acid. Examples include, but are not limited to, a copolymerized polymer using a mixture of racemic lactic acid as a monomer.
[0017]
Similarly, examples of poly (β-hydroxyalkanoates) constituting the sheath component include poly-3-hydroxybutyrate, poly-3-hydroxyvalerate, and poly-3-hydroxy (butyrate / valerate). However, the present invention is not limited to this.
[0018]
In addition, for each polymer used in the present invention, for example, various additives such as pigments, dyes, light-resistant agents, ultraviolet absorbers, antioxidants, crystallization inhibitors, and plasticizers are not excluded from the intended performance. In the range, it can be added after the polymerization step, after polymerization or just before spinning.
[0019]
The object of the present invention is to obtain a monofilament having a balance between sufficient mechanical performance and biodegradability as a fiber used for marine materials or various industrial materials. Here, the mechanical performance is obtained. The biodegradability will be described as follows.
[0020]
That is, the mechanical performance as a fiber in the present invention is particularly wear resistance and fatigue resistance. Of course, basic performance such as a certain degree of tensile strength is necessary, but it is also necessary to combine this wear resistance and fatigue resistance under the conditions necessary for fibers used in marine materials or various industrial materials. is there.
[0021]
As noted above, biodegradable polymers include polybutylene succinate, polyethylene succinate, polybutylene (succinate / adipate) , poly (β-hydroxyalkanoates), polylactic acid, polyglycolic acid, and poly-ε- Although caprolactone and the like are present, it has been difficult to provide both wear resistance and fatigue resistance with fibers made of each polymer alone. For example, fibers made from port polybutylene succinate (flexural modulus 0.7 GPa) is excellent in fatigue resistance inferior in wear resistance, the polylactic acid (flexural modulus 3.3 GPa) or poly (beta-hydroxy The fibers made from poly-3-hydroxy (butyrate / valerate) (flexural modulus 2.7 GPa) representing alkanoates generally have excellent wear resistance but poor fatigue resistance. There was a contradictory aspect.
[0022]
Therefore, as a result of intensive studies aimed at producing fibers excellent in both of these characteristics, the present inventors have selected from polybutylene succinate, polyethylene succinate, and polybutylene (succinate / adipate) having a relatively low flexural modulus. The composite monofilament with at least one kind of core component and polylactic acid and poly (β-hydroxyalkanoate) having a relatively high flexural modulus as sheath components is excellent in both wear resistance and fatigue resistance. It was found that a good fiber was obtained.
[0023]
In particular, the composite monofilament in which the weight ratio of the core component / sheath component is in the range of 95/5 to 40/60 is high in strength, and also has a good difficulty in chilling when used as a fishing line. It is extremely excellent as a fishing line.
[0024]
Next, biodegradability will be described. Biodegradability is difficult to evaluate objectively, but generally the tensile strength decreases to 50% or less or disappears in about 3 to 6 months in the natural environment (for example, in the soil). Is ideal. As a technique for controlling biodegradability, a core-sheath composite fiber technique in which a sheath component is a polymer having a relatively slow degradation rate and a core component is a polymer having a faster degradation rate than the sheath component (Japanese Patent Laid-Open No. 7-305234 and special patents). (Kaihei 7-324277) is already known, but the biodegradable composite monofilament of the present invention is, on the contrary, a polymer whose sheath component is relatively fast and whose core component is relatively slow. In that respect, the technical idea is different from that of the prior art.
[0025]
However, contrary to expectation, the composite monofilament made in the present invention is excellent in biodegradability and has mechanical properties such as tensile strength, knot strength, wear resistance and fatigue resistance as compared with the prior art. It was found to be extremely useful as a fishery material represented by fishing lines.
[0026]
The biodegradable composite monofilament of the present invention can be efficiently produced by the method described below.
[0027]
First, when melt spinning the biodegradable composite monofilament, normal conditions using an extrusion spinning machine for core-sheath composite can be employed, polymer temperature 170 to 240 ° C., extrusion pressure 10 to 500 Kg / cm ³ , Conditions such as a nozzle hole diameter of 0.1 to 5 mm and a spinning speed of 0.3 to 100 m / min can be appropriately selected.
[0028]
The spun monofilament is cooled in a cooling bath after passing through a short gas zone, where a liquid inert to the polymer, usually water, is used as the cooling medium. In addition, the cooling temperature needs to be 60 ° C. or less, and when cooling at a temperature exceeding that, the stretchability in the next stretching step may be hindered.
[0029]
The cooled and solidified monofilament is subsequently sent to the first drawing step. As the drawing and heat setting atmosphere (bath), a heated heat medium such as polyethylene glycol, glycerin and silicone oil, a dry heat gas bath, And a warm water bath is used.
[0030]
Next, when performing stretching, the first stage stretching is first set at a magnification of 2.5 to 5.0 times, and then the second stage or 2-3 at a stretching ratio at which the total stretching ratio becomes 6.0 times or more. Multi-stage stretching of the stage is performed.
[0031]
Here, when the draw ratio of the first stage is less than 2.5 times and 6.0 or more, yarn breakage is likely to occur in the next step, which is not preferable.
[0032]
Moreover, if the total draw ratio is less than 6.0 times, the tensile strength and knot strength of the obtained monofilament are lowered, which is not preferable.
[0033]
After multi-stage stretching, an appropriate constant length and relaxation heat treatment can be performed for the purpose of removing stretching strain as necessary.
[0034]
The biodegradable composite monofilament of the present invention thus obtained has mechanical performance as a fiber such as strength, abrasion resistance and fatigue resistance, and moderate biodegradability (tensile strength in 3 to 6 months in soil. Is reduced to 50% or less, or the shape disappears). Therefore, it is extremely useful as a variety of industrial materials, especially fishery materials such as fishing lines, fishing nets, ginger nets, and especially fishing lines.
[0035]
【Example】
Hereinafter, the present invention will be further described based on examples. Evaluation of monofilaments in the examples was performed according to the following method.
[0036]
(1) Tensile strength and knot strength: Measured according to JIS L1013.
(2) Difficulty in curling: The results of relative evaluation of monofilament curling after visual observation of 3 hours of winding of a monofilament on a spinning reel and actual lure fishing were shown by the following criteria.
○ There is almost no jijire △ There is a little jijire x Chijire is bad.
(3) Abrasion resistance: A # 320 sandpaper is wrapped around the surface of a rotating body having a diameter of 50 mm and rotated at 180 rpm. On the other hand, a load of 1/20 denier was applied to the monofilament so that the monofilament was vertically brought into contact with the rotating body at an angle of 90 °, and the number of rotations (times) until the monofilament was cut was measured. The number of tests was 5, and the average value was shown. The higher the number of times, the better the wear resistance.
(4) Fatigue resistance: Measured using a bending fatigue tester (manufactured by TOYOSEIKI). That is, when a load of 500 g is applied to one end of a monofilament having a test length of 8 cm and the chuck is moved to a pendulum at a swing angle of 220 ° and a rotation speed of 180 times / minute on the other end, the monofilament is cut. The number of exercises was measured. The number of tests was 5, and the average value was shown. The greater the number of times, the better the bending fatigue resistance.
[0037]
(5) Biodegradability: The material is left in the soil for 3 months and taken out. If the monofilament has lost its shape or the tensile strength retention rate is 50% or less, the biodegradability is good. Those that were shown but did not reach it were rated as “slightly slow”.
[0038]
[Example 1]
Polybutylene succinate (MI: 1.0 g / 10 min, melting point: 114 ° C., polymer A1) is used as a core component (80 parts by weight), and poly-L-lactic acid (MI: 1.5 g / 10 min, melting point: 175). C. Polymer B1) as a sheath component (20 parts by weight) was melted at 230.degree. C. with an extruder type composite spinning machine, spun through a die having a pore diameter of 1.5 mm, and further cooled in a water bath at 20.degree.
[0039]
Next, this undrawn yarn was drawn 4.5 times (E1) in a first-stage drawing bath at 70 ° C. in warm water, followed by 2.13 times (E2) in a second-stage dry heat bath at 85 ° C. ) To obtain a monofilament having a total draw ratio (E1 × E2) of 9.6 times.
[0040]
Subsequently, a monofilament having a diameter of 0.22 mm was obtained by passing through a dry heat bath at 80 ° C. at a treatment magnification of 0.9 times and performing heat treatment.
[0041]
[Example 2]
Polybutylene (succinate / adipate) (MI: 1.5 g / 10 min, melting point: 95 ° C., polymer A2) is used as a core component (80 parts by weight), and poly-3-hydroxy (butyrate / valerate) (MI: 8 g / 10) Min, melting point: 162 ° C. Polymer B2) as a sheath component (20 parts by weight) was melt spun and cooled in the same manner as in Example 1 to obtain an undrawn yarn.
[0042]
Next, this unstretched yarn was stretched 3.7 times (E1) in a first-stage stretching bath at 80 ° C. in warm water, and subsequently 2.22 times (E2 in a second-stage dry heat bath at 95 ° C.). ) To obtain a monofilament having a total draw ratio (E1 × E2) of 10.0 times.
[0043]
Subsequently, a 0.22 mm monofilament was obtained by passing through a dry heat bath at 80 ° C. at a treatment magnification of 0.9 times to perform heat treatment.
[0044]
[Example 3]
Polymer A1 used in Example 1 was used as a core component (70 parts by weight), and a blend polymer of polymer B1 (15 parts by weight) used in Example 1 and polymer B2 (15 parts by weight) used in Example 2 was sheathed. As components, melt spinning and cooling were performed in the same manner as in Example 1 to obtain an undrawn yarn.
[0045]
Next, this unstretched yarn was stretched 4.3 times (E1) in a first-stage stretching bath at 75 ° C. in warm water, and subsequently 2.18 times (E2) in a second-stage stretching bath at 90 ° C. And a monofilament having a total draw ratio (E1 × E2) of 9.4 times was obtained.
[0046]
Subsequently, a monofilament having a diameter of 0.22 mm was obtained by subjecting it to a dry heat bath at 80 ° C. with a treatment magnification of 0.9 times.
[0047]
[Comparative Example 1]
A monofilament having a diameter of 0.22 mm was obtained by the same production method as in Example 1 except that the polymer A1 used in Example 1 alone was used.
[0048]
[Comparative Example 2]
A monofilament having a diameter of 0.22 mm was obtained by the same production method as in Example 1 except that the polymer B1 used in Example 1 alone was used.
[0049]
[Comparative Example 3]
A monofilament having a diameter of 0.22 mm was obtained by the same production method as in Example 2, except that the polymer B2 used in Example 2 was used alone.
[0050]
[Comparative Example 4]
A monofilament having a diameter of 0.22 mm was obtained by the same manufacturing method as in Example 1 except that the polymer B1 used in Example 1 was a core component (80 parts by weight) and the polymer A1 was a sheath component (20 parts by weight). .
[0051]
[Comparative Example 5]
A monofilament having a diameter of 0.22 mm was obtained by the same production method as in Example 2, except that the polymer B2 used in Example 2 was a core component (80 parts by weight) and the polymer A2 was a sheath component (20 parts by weight). .
[0052]
[Comparative Example 6]
In Example 2, a monofilament having a diameter of 0.22 mm was obtained by the same manufacturing method as Example 2 except that the ratio of the polymer A2 as the core component was 97 parts by weight and the ratio of the polymer B2 as the sheath component was 3 parts by weight. It was.
[0053]
[Comparative Example 7]
In Example 1, a monofilament having a diameter of 0.22 mm was obtained by the same manufacturing method as in Example 1 except that the ratio of the polymer A1 as the core component was 30 parts by weight and the ratio of the polymer B1 as the sheath component was 70 parts by weight. It was.
[0054]
For each monofilament obtained in Examples 1 to 3 and Comparative Examples 1 to 7, the results of evaluating the above-mentioned characteristics as a monofilament are shown in Table 1.
[0055]
[Table 1]

As is apparent from the results in Table 1, at least one selected from polybutylene succinate, polyethylene succinate, and polybutylene (succinate / adipate) having a melting point of 70 ° C. or higher is used as a core component, and polylactic acid and its co- polymer are used. A monofilament of the present invention in which at least one selected from polymerized polymers and poly (β-hydroxyalkanoates) is a sheath component and the weight ratio of the core component to the sheath component is in the range of 95/5 to 40/60 (Examples) 1-3) has excellent mechanical performance as a fiber and biodegradability, and ideally satisfies the required performance as a biodegradable monofilament.
[0056]
In addition, when this biodegradable composite monofilament was actually used as a fishing line, there was almost no wrinkle after use and it was very good as a fishing line.
[0057]
On the other hand, monofilaments (Comparative Examples 1 to 3) each using polybutylene succinate , polylactic acid, and poly (β-hydroxyalkanoate) alone, and polylactic acid and copolymer thereof, poly (β-hydroxyalkano) A composite monofilament in which the core / sheath component is reversed from that of the present invention (Comparative Example 4), wherein the core component is at least one member selected from the group consisting of ate) and the sheath component is a polyalkylene dicarboxylate having a melting point of 70 ° C or higher. 5) was inferior in strength, wear resistance, fatigue resistance, or biodegradability, and did not satisfy the required performance in marine material applications.
[0058]
Moreover , the composite monofilaments (Comparative Examples 6 and 7) in which the weight ratio of the core component / sheath component deviated from the range of 95/5 to 40/60 did not sufficiently satisfy the intended effect of the present invention.
[0059]
【The invention's effect】
As described above, the biodegradable composite monofilament of the present invention is excellent in balance between mechanical performance and biodegradability as a fiber. It satisfies the required performance as a monofilament for industrial materials, especially for marine products, and especially for fishing lines.

Claims (5)

At least one selected from polybutylene succinate, polyethylene succinate, and polybutylene (succinate / adipate) having a melting point of 70 ° C. or higher is used as a core component, and polylactic acid, a copolymer of polylactic acid, and poly (β-hydroxy) A biodegradable composite monofilament wherein at least one selected from alkanoates) is used as a sheath component and the weight ratio of the core component / sheath component is in the range of 95/5 to 40/60. The polylactic acid is poly-L-lactic acid and / or poly-D-lactic acid, and the copolymer of polylactic acid is a copolymer having a mixture of L-lactic acid / D-lactic acid / racemic lactic acid as a monomer. biodegradable composite monofilament according to claim 1 Symbol mounting features. The poly (β-hydroxyalkanoate) is at least one selected from poly-3-hydroxybutyrate, poly-3-hydroxyvalerate, and poly-3-hydroxy (butyrate / valerate). claim 1 Symbol placement biodegradable composite monofilament to. Fishery materials, characterized in that it consists of claims 1-3 biodegradable composite monofilament according. It consists claim 1-3 biodegradable composite monofilament according, and a tensile strength 4.0 g / d or more, knot strength 3.0 g / d or more fishing line.