JPH0974961A - Biodegradable fishline and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a biodegradable fishline combinedly having basic properties as a fishline and a suitable biodegrading rate, and to provide a method for efficiently producing the biodegradable fishline. SOLUTION: This biodegradable fishline is composed of a monofilament comprising an aliphatic polyester having <=10g/10min melt index measured at 190 deg.C under 2.16kg load and 70-180 deg.C melting point as a main component, and having >=5.0g/d tensile strength, >=4.0g/d knot strength, <=53×10<-3> orientation of the surface layer (birefringence Δns by Becke's method) and >=55×10<-3> whole orientation (birefringence ΔnT by a retardation method). The biodegradable fishline is produced by melt spinning a polymer mainly composed of an aliphatic polyester, cool-solidifying in an inert liquid at <=60 deg.C, successively performing first drawing at 2.5-5.0 times of draw ratio, when subjecting to multiple drawing so as to attain whole draw ratio of >=6.0 times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable fishing line having a basic performance as a fishing line and an appropriate biodegradation rate, and a method for producing the same.

[0002]

2. Description of the Related Art As conventional fishing line materials, synthetic fibers mainly composed of polyamide, polyester, polyolefin, polyvinylidene fluoride and the like have been used because of their mechanically required properties. However, fishing lines made of these synthetic fibers are hardly decomposed in a natural environment, so if they are thrown away after use or left unattended,
As it was, it remained semi-permanently in the natural world, which was a major environmental health problem.

More specifically, abandoned discarded fishing lines often stand on the seabed, and the discarded fishing lines and cut fishing lines are often entangled with birds and marine life and killed. There has been a strong demand for improvement in terms of both protection and nature protection. Therefore, recently, a fishing line that is biodegraded by fungi and microorganisms in the natural world after use and disappears spontaneously, that is, a biodegradable fishing line has been actively developed, and a typical technique regarding these biodegradable fishing lines is, for example, ( A) Fishing line made of polylactide (Japanese Patent Application Laid-Open No. 3-183428)
(Japanese Patent Laid-Open No. 5-529), (B) a fishing line made of polyglycolic acid (Japanese Patent Laid-Open No. 3-259029), and (C) a fishing line made of polycaprolactone monofilament (Japanese Patent Laid-Open No. 5-5).
9611) and (D) polybutylene succinate or / and polyethylene succinate as a raw material (JP-A-7-126914).

However, the above-mentioned biodegradable fishing lines (A) and (B) are said to satisfy the basic performance as a fishing line because they are hard and brittle in material and have low knot strength. hard. In addition, since the biodegradable fishing line of (C) has a low melting point of about 60 ° C., it is liable to cause scratches and scratches due to rubbing, and the biodegradable fishing line of (D) has mechanical strength and the like. Although it has excellent biological properties, it has a drawback that the biodegradation rate is slow.

Therefore, none of the conventional biodegradable fishing lines have a basic performance as a fishing line and an appropriate biodegradation rate, and it is the actual situation that improvement thereof is strongly desired. .

[0006]

The present invention has been achieved as a result of investigations for solving the above-mentioned problems of the prior art. Therefore, an object of the present invention is to provide a biodegradable fishing line having both a basic performance as a fishing line and an appropriate biodegradation rate, and a method for efficiently producing the biodegradable fishing line.

[0007]

In order to achieve the above-mentioned object, the biodegradable fishing line of the present invention has a temperature of 190 ° C. and a load of 2.1.
Melt index measured under the condition of 6 kg is 10 g / 1
It is composed of a monofilament composed mainly of an aliphatic polyester having a melting point of 70 to 180 ° C. for 0 minutes or less, a tensile strength of 5.0 g / d or more, and a knot strength of 4.0 g.
/ D or more, the degree of orientation of the surface layer (the birefringence Δn _S by the Becke method) is 53 × 10 ⁻³ or less, and the overall degree of orientation (the birefringence Δn _T by the retardation method) is 55 × 10 ⁻³ or more. It is characterized by being.

The method for producing a biodegradable fishing line of the present invention has a melt index of 10 g / 10 minutes or less and a melting point of 70 to 18 measured under the conditions of 190 ° C. and a load of 2.16 kg.
A polymer containing an aliphatic polyester as a main component, which is 0 ° C., is melt-spun, cooled and solidified in an inert liquid at 60 ° C. or less, and subsequently, a first stage drawing is performed at a magnification of 2.5 to 5.0 times. The biodegradable fishing line comprising monofilaments having the above characteristics is produced by performing multistage drawing at a draw ratio that makes the total draw ratio 6.0 or more.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The aliphatic polyester used in the present invention is 190
Melt index (hereinafter referred to as MI) measured under conditions of ℃ and load of 2.16 kg is 10 g / d or less and melting point is 70.
It is an aliphatic polyester of 180 ° C. Specific examples thereof include random copolymers of succinic acid, adipic acid and 1.4-butanediol, and blend polymers of the random copolymers with polybutylene succinate and / or polyethylene succinate, but are not limited thereto. is not.

The composition ratio of succinic acid / adipic acid in the above random copolymer is 75-85 / 25-
A range of 15 (molar ratio) is suitable. The aliphatic polyester used in the present invention preferably has an MI of 10 g / d or less, particularly 1 g / d or less, and when it exceeds 10 g / d, it is not preferable because sufficient physical properties as a fishing line cannot be obtained. .

The melting point of the aliphatic polyester used in the present invention needs to be in the range of 70 to 180 ° C, and particularly preferably 80 to 135 ° C. If the temperature is lower than 70 ° C, only a monofilament having insufficient heat resistance and easily causing scratches and crimps is obtained. If the temperature exceeds 180 ° C, the spinnability is impaired, which is not preferable. Here, in the case of a blend polymer, the melting point of any of the random copolymer, polybutylene succinate and / or polyethylene succinate is in the range of 70 to 180 ° C., and the MI of the melt of the blend composition is 10 g / It may be 10 minutes or less.

Further, the aliphatic polyester used in the present invention contains additives such as pigments, dyes, light stabilizers, ultraviolet absorbers, antioxidants, crystallization inhibitors and plasticizers.
It can be added in the polymerization process, after the polymerization, or immediately before spinning, within the range that the desired characteristics are not excluded. Furthermore, in the biodegradable fishing line of the present invention, a monofilament made of an aliphatic polyester as a constituent material thereof has a tensile strength of 5.0 g / d or more, a knot strength of 4.0 g / d or more, and a degree of orientation of the surface layer (Becke method. Birefringence Δn _S ) 53 ×
It is characterized in that it has characteristics of 10 ⁻³ or less, and an overall degree of orientation (birefringence Δn _T by retardation method) of 55 × 10 ⁻³ or more.

An object of the present invention is to obtain a biodegradable fishing line having both a basic performance as a fishing line and an appropriate biodegradation rate. Here, the basic performance as a fishing line and an appropriate biodegradation are obtained. The speed is as follows. The basic performance as a fishing line is the minimum strength that can withstand practical use (tensile strength: 5.0 g / d, knot strength: 4.0 g /
It is heat-resistant so that it does not cause scratches or abrasion due to rubbing.

On the other hand, with a moderate biodegradation rate as a fishing line, it is ideal that the shape disappears in 3 months to 1 and a half years under natural environment (for example, seawater). However, the evaluation in the natural environment has poor reproducibility, and it is difficult to make an objective evaluation. Therefore, as a result of examining a relatively objective and appropriate evaluation method for the biodegradation rate of fishing line,
It was found that about 1/20 times the biodegradation rate when embedded in compost (according to ASTM-D-5338-92) corresponds to the biodegradation rate in the natural environment.

That is, it was found that the shape disappearance in the natural environment for 3 months to 1 year and a half corresponds to the shape disappearance in the compost for about 4 days to 4 weeks. Therefore, an appropriate biodegradation rate as a fishing line in the present invention means that the shape disappears in about 4 days to 4 weeks when buried in compost. And the degree of orientation of the surface layer is 53 × 1
The fishing line of the present invention composed of an aliphatic polyester monofilament having a degree of orientation of 0 ^-3 or less and an overall degree of orientation of 55 × 10 ^-3 or more has a tensile strength of 5.0 g / d or more and a knot strength of 4.0 g.
The reason why it has an appropriate biodegradation rate as a fishing line while having a high strength of / d or more is not necessarily clear, but it can be reasoned as follows.

That is, although aliphatic polyesters are generally biodegradable polymers, when highly stretched to obtain the high strength required for fishing lines, they have a high degree of orientation and accompanying oriented crystals. The degree of crystallinity tends to increase, and the biodegradation rate tends to be extremely slow.This is because the fiber structure is extremely dense and strong due to the high degree of orientation and high crystallinity,
This is probably because the attack of the degrading bacteria is blocked.

On the other hand, the degree of orientation of the surface layer is 53 × 10.
^-3Below, the overall degree of orientation is 55 × 10. ^-3Fat controlled above
The raw material of the present invention comprising an aliphatic polyester monofilament
Degradable fishing line has a degree of crystallinity (usually extended for fishing line).
If the stretched orientation is 20 to 50%), the surface layer portion is
It becomes more susceptible to attack by sterilization, and the decomposition of the surface layer is rate-determining.
Since there are many cases, it is thought that the biodegradation rate will be appropriate.
Can be

The biodegradable fishing line of the present invention having the above characteristics can be efficiently produced by the method described below. First, when melt-spinning the above aliphatic polyester, usual conditions using an extrusion spinning machine can be adopted. For example, a polymer temperature of 170 to
Conditions such as 240 ° C., extrusion pressure 10 to 500 kg / cm ² , spinneret hole diameter 0.1 to 5 mm, spinning speed 0.3 to 100 m / min can be appropriately selected.

After passing through the short gas zone, the spun monofilaments are cooled in a cooling bath, where a liquid inert to the aliphatic polyester is used as the cooling medium.
Water is usually used. Further, the cooling temperature needs to be 60 ° C. or lower, and if it is cooled at a temperature higher than 60 ° C., the stretchability in the next stretching step may be impaired. The cooled and solidified monofilament is continuously sent to the first drawing step. As an atmosphere (bath) for drawing and heat setting, for example, a heated heat medium bath such as polyethylene glycol, glycerin and silicone oil, a dry heat gas is used. A bath and a hot water bath are used.

Next, when stretching is carried out, first, the first stage of stretching is set to a draw ratio of 2.5 to 5.0 times, and then the second stage or the total draw ratio is 6.0 times or more. Two
It is important to carry out the multi-stage drawing of the third stage. here,
If the draw ratio in the first step is less than 2.5 times, yarn breakage during drawing will frequently occur and a good monofilament will not be obtained.
If it exceeds 5.0 times, the degree of orientation of the surface layer is 53 × 10 ^−3.
This is not preferable because the following does not occur and the biodegradation rate of the obtained fishing line becomes slow.

If the total draw ratio is less than 6.0 times,
Because the tensile strength and knot strength of the fishing line to be
Not good. After multi-stage stretching, stretch strain may be applied if necessary.
For the purpose of removal, etc., an appropriate constant length and relaxation heat treatment
You can also do things. However, the above manufacturing method
Tensile strength of 5.0 g / d or more, knot strength of 4.0 g / d or less
The degree of orientation of the upper and surface layers is 53 × 10^-3Below, the overall orientation
Degree is 55 × 10 ^-3More than aliphatic polyester monof
Is one way to earn
It is not something to be done.

For example, as a means for lowering the degree of orientation of the surface layer, a method of performing heat treatment for a short time at a high temperature equal to or higher than the melting point after stretching can be adopted. Thus, the monofilament of the aliphatic polyester obtained by the efficient manufacturing process has a tensile strength of 5.0 g / d.
As described above, the knot strength is 4.0 g / d or more, the degree of orientation of the surface layer (birefringence Δn _S by the Becke method) is 53 × 10 ⁻³ or less, and the degree of overall orientation (birefringence Δn _T by the retardation method) Has a characteristic of 55 × 10 ^-3 or more, and has basic performance as a fishing line (high strength and heat resistance, etc.) and an appropriate biodegradation rate (decomposed in about 1 to 4 weeks after being buried in compost). ), It is extremely useful as a biodegradable fishing line.

[0023]

EXAMPLES Next, the present invention will be described based on examples. The fishing line according to the present invention was evaluated according to the following methods. (1) Tensile strength and knot strength: Measured according to JIS L1013. (2) Degree of orientation of surface layer (birefringence Δn _S ): measured by Becke method.

(3) Orientation degree (birefringence Δn _T ) of the whole:
It was measured by the retardation method. (4) Density: Measured by the density gradient tube method. (5) Biodegradation rate: buried in compost (ASTM-D-
(According to 5338-92) When the shape disappeared from about 4 days to 4 weeks was evaluated as “good”, and when the shape did not disappear after 4 weeks, it was evaluated as “slow”.

Example 1 Succinic acid / adipic acid (80/20 mol%) and 1.
Random copolymer with 4-butanediol (MI:
1.0 g / 10 minutes, melting point: 95 ° C .... Polymer A1) was melted at 230 ° C. by an extruder type spinning machine to give a pore size of 1.
It was spun through a 5 mm spinneret and further cooled in a 20 ° C. water bath.

Next, this unstretched yarn was stretched 4.5 times (E1) in a hot water first stage stretching bath at 70 ° C., and subsequently at 85 ° C.
Was stretched to 2.22 times (E2) in the second stage dry heat bath to obtain an aliphatic polyester monofilament having a total draw ratio (E1 × E2) of 10.0 times. Subsequently, the product was passed through a dry heat bath at 80 ° C. at a processing magnification of 0.9 times and heat-treated to obtain a monofilament having a diameter of 0.22 mm.

Example 2 Succinic acid / adipic acid (80/20 mol%) and 1.
Random copolymer with 4-butanediol (MI:
0.5 g / 10 minutes, melting point: 95 ° C .... Polymer A2),
Melt spinning and cooling of a 50/50 (part by weight) blend polymer (MI: 0.5 when the mixed composition melted) with polybutylene succinate (polymer B) having a melting point of 114 ° C. was carried out in the same manner as in Example 1. Then, an undrawn yarn was obtained.

Next, the undrawn yarn was drawn 3.7 times (E1) in a first drawing bath of warm water at 80 ° C., and subsequently at 95 ° C.
Was stretched to 2.16 times (E2) in the second stage dry heat bath to obtain an aliphatic polyester monofilament having a total draw ratio (E1 × E2) of 8.0 times. Then, by passing it through a dry heat bath at 80 ° C. at a treatment magnification of 0.9 times, and subjecting it to heat treatment,
A monofilament having a diameter of 0.22 mm was obtained.

Example 3 50/50 of polymer A2 used in Example 2 and polyethylene succinate (polymer C) having a melting point of 104 ° C.
(Parts by weight) of Brent polymer (M when the mixed composition is melted
I: 0.5) was melt-spun and cooled in the same manner as in Example 1 to obtain an undrawn yarn. Next, this unstretched yarn was stretched 4.3 times (E1) in a first stage drawing bath of warm water at 75 ° C, and subsequently 90 ° C.
Was stretched to 2.09 times (E2) in the second-stage dry heat bath to obtain an aliphatic polyester monofilament having a total draw ratio (E1 × E2) of 9.0 times.

Then, in a dry heat bath at 80 ° C., a treatment ratio of 0.
By passing through 9 times and subjecting to heat treatment, a diameter of 0.22
mm monofilament was obtained. Example 4 The polymer B2 / polymer B / polymer C 50/25/25 (parts by weight) Brent polymer (MI: 0.7 when melted in mixed composition) used in Examples 2 and 3 was used as Example 1. Similarly, melt spinning and cooling were performed to obtain an undrawn yarn.

Next, the undrawn yarn was drawn 4.0 times (E1) in a first drawing bath of warm water of 80 ° C., and subsequently 90 ° C.
Was stretched 2.13 times (E2) in the dry heat bath to obtain an aliphatic polyester monofilament having a total stretching ratio (E1 × E2) of 8.5 times. Subsequently, the product was passed through a dry heat bath at 80 ° C. at a processing magnification of 0.9 times and heat-treated to obtain a monofilament having a diameter of 0.22 mm.

Comparative Example 1 Succinic acid / adipic acid (80/20 mol%) and 1.
Random copolymer of 4-butanediol (MI:
13 g / 10 min, melting point: 95 ° C .... A monofilament having a diameter of 0.22 mm was obtained by the same production method as in Example 1 except that Polymer A3) was used.

Comparative Example 2 The same production method as in Example 1 except that the first stage draw ratio was 5.3 times (E1) and the second stage draw ratio was 1.89 times (E2), the diameter was 0.22 mm. Of monofilament was obtained. Comparative Example 3 A monofilament having a diameter of 0.22 mm was prepared in the same manner as in Example 1 except that the first-stage draw ratio was 2.3 times (E1) and the second-stage draw ratio was 4.35 times (E2). Although it was attempted to obtain it, yarn breakage during drawing was remarkable, and it was impossible to produce yarn.

Comparative Example 4 The same production process as in Example 2 was repeated except that the first draw ratio was 6.0 times (E1) and the second draw ratio was 1.33 times (E2). A 22 mm monofilament was obtained. Comparative Example 5 A monofilament having a diameter of 0.22 mm was produced in the same manner as in Example 3, except that the first-stage draw ratio was 5.7 times (E1) and the second-stage draw ratio was 1.58 times (E2). Got

Comparative Example 6 Polymer A1 of Example 1 and 10/90 (parts by weight) of Brent polymer (MI: 1.0 when the mixed composition melted) of Polymer B used in Example 2 were used. Melt spinning and cooling were performed in the same manner as in 1. to obtain an undrawn yarn. Next, the undrawn yarn is
Stretched 3.7 times (E1) in the first drawing bath of warm water at ℃,
Subsequently, the film was stretched to 1.49 times (E2) in a dry heat second stage drawing bath at 100 ° C., and the total draw ratio (E1 × E2) was 5.5.
A double aliphatic polyester monofilament was obtained.

Then, in a dry heat bath at 80 ° C., a treatment ratio of 0.
By passing through 9 times and subjecting to heat treatment, a diameter of 0.22
mm monofilament was obtained. Table 1 also shows the results of evaluating the above-mentioned physical properties of the obtained monofilaments as a fishing line.

[0037]

[Table 1]

As is clear from the results of Table 1, MI is 1
It is composed mainly of an aliphatic polyester having a melting point of 70 to 180 ° C. of 0 g / 10 minutes or less and a tensile strength of 5.
0 g / d or more, the knot strength is 4.0 g / d or more, and the degree of orientation of the surface layer (the birefringence Δn _S by the Becke method) is 53 × 1.
The fishing line (Examples 1 to 4) of the present invention having a degree of orientation of 0 ^-3 or less and a total orientation degree (birefringence index Δn _T by the retardation method) of 55 × 10 ^-3 or more has basic performance as a fishing line. It has a moderate biodegradation rate and satisfies the required performance as a biodegradable fishing line.

On the other hand, an aliphatic polyester having a MI of more than 10 g / 10 min was used, and the degree of orientation of the whole was 55.0 × 10 5.
^The fishing line of less than ^-3 (Comparative Example 1) has a good biodegradation rate, but does not satisfy the tensile strength and the knot strength. In addition, the fishing line drawn in the first stage with a draw ratio of more than 5.0 and the degree of orientation of the surface layer exceeds 53.0 × 10 ⁻³ (Comparative Examples 2, 4, 5).
, The tensile strength is satisfied, but the knot strength and biodegradation rate are not satisfied.

Further, a fishing line (comparative example 6) having a total orientation of less than 6.0 times and an overall degree of orientation of less than 55.0 × 10 ^-3 is
Biodegradation rate is good, but tensile strength and knot strength are not satisfied. When the first-stage drawing was drawn at a draw ratio of less than 2.5 times (Comparative Example 3), it was not possible to adopt a condition in which the draw ratio was high because of all yarn breakage.

[0041]

As described above, the fishing line formed from the monofilament containing the aliphatic polyester as the main component of the present invention has both basic performance as a fishing line and an appropriate biodegradation rate. It sufficiently satisfies the required performance as a biodegradable fishing line, which is strongly desired to be improved from both aspects of environment and nature protection.

The method for producing a biodegradable fishing line of the present invention is extremely efficient because the ordinary spinning and drawing method can be applied as it is.

Claims (3)

[Claims] 1. A monofilament composed mainly of an aliphatic polyester having a melt index of 10 g / 10 minutes or less and a melting point of 70 to 180 ° C. measured under the conditions of 190 ° C. and a load of 2.16 kg, and has a tensile strength. Is 5.0 g / d or more, the knot strength is 4.0 g / d or more, and the degree of orientation of the surface layer (the birefringence Δn _S by the Becke method) is 53.
× 10 ^-3 or less, biodegradable fishing line is characterized in that it is 55 × 10 ^-3 or more (birefringence [Delta] n _T by retardation method) overall degree of orientation. 2. The aliphatic polyester is a random copolymer of succinic acid, adipic acid and 1.4-butanediol, or a blend polymer of the random copolymer and polybutylene succinate or / and polyethylene succinate. The biodegradable fishing line according to claim 1. 3. A polymer comprising an aliphatic polyester as a main component having a melt index of 10 g / 10 minutes or less and a melting point of 70 to 180 ° C. measured at 190 ° C. and a load of 2.16 kg, and melt-spun at 60 ° C. After being cooled and solidified in the following inert liquid, the first stage drawing is subsequently performed at a draw ratio of 2.5 to 5.0 times, and then the multi-step drawing is performed at a draw ratio that makes the total draw ratio 6.0 or more. The tensile strength is 5.0 g / d or more, the knot strength is 4.0 g / d or more, and the degree of orientation of the surface layer (the birefringence Δn _S by the Becke method) is 5
3 × 10 ^-3 or less, the manufacturing method of the biodegradable fishing line overall orientation (birefringence [Delta] n _T by retardation method) consists of monofilaments is 55 × 10 ^-3 or more.