JP2000192333A - Monofilaments of lactic acid based resin excellent in processability for secondary processing and weatherability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain monofilaments of polylactic acid based resin excellent in processability for secondary processing such as forming net, fishing net and rope or the like and weatherability by applying a lipophilic lubricant after melt spinning polylactic acid resin composition including carbon based filler. SOLUTION: Monofilaments of polylactic acid based resin are obtained by melt spinning the polylactic acid based resin composition comprising 100 pts.wt. of the polylactic acid based resin such as polylactic acid or the like and 0.005-10 pts.wt. of carbon based filler such as carbon black, applying the lipophilic lubricant for example, a petroleum based lubricant having kinetic viscosity of 1-500 mm2S at 40 deg.C after spinning, the monofilaments manifest 2.0-10.0 g/d of tensile strength, 5.0-50.0% of the tensile elongation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is biodegradable and has excellent secondary workability when formed into nets, fish nets and ropes.
The present invention also relates to a lactic acid-based resin monofilament excellent in durability (weather resistance) when used in a natural environment.

[0002]

2. Description of the Related Art In general, polymer materials (mainly thermoplastic polymer materials) represented by polyolefins, polystyrenes, polyesters, polyamides, polyacrylates, polycarbonates, polyimides, etc., are in our daily lives. It is an indispensable material. However, these ordinary polymer materials have completed their mission of use, and when disposed of, are hardly decomposed in the natural environment. Therefore, when they are buried, they remain semi-permanently in the ground and are incinerated. In this case, there are problems such as air pollution by waste gas and shortening of the life of the incinerator due to incineration heat energy. In addition, ordinary polymer materials are hardly decomposed in the natural environment, so they damage the landscape, pollute the environment, destroy the living environment of marine life, and have many environmental conservation problems. And new materials are eagerly needed.

[0003] From such a background, degradability and / or biodegradability (in the specification of the present application, the function of decomposing under the action of microorganisms in a natural environment and the function of decomposing in vivo by the action of enzymes and the like) As a thermoplastic resin having polylactic acid, a copolylactic acid having a lactic acid component as a main component (for example, a copolymer of lactic acid and another aliphatic hydroxycarboxylic acid), a polylactic acid and another aliphatic polyester. (For example, a mixture of polylactic acid and polybutylene succinate) has attracted attention. Polylactic acid biodegrades 100% within the body of an animal within several months to one year, and when left in wet conditions such as soil or seawater, its strength starts to decrease in about a few weeks, and from about one year to several years. It is characteristic that it disappears without retaining its original form in about a year, and that the decomposition product has the property of becoming lactic acid and / or carbon dioxide and water harmless to the human body.

[0004] Lactic acid, which is a raw material of polylactic acid, is produced by a fermentation method or a chemical synthesis method. Recently, in particular, L-lactic acid has been produced in large quantities by the fermentation method, and its price has become inexpensive. Development of various applications utilizing the characteristics of polylactic acid having excellent transparency and rigidity is being promoted.

The present invention relates to a monofilament made of this lactic acid-based resin, and several techniques relating to this have already been disclosed. For example, polylactic acid fibers comprising a blend of poly-L-lactic acid and poly-D-lactic acid (JP-A-63-264913), yarns comprising polylactic acid as a constituent material (JP-A-3-183428), A method for producing a polylactic acid-based resin filament using at least two or more stretching steps (Japanese Patent Application Laid-Open No. 10-60733) is known.

[0006] These techniques are certainly techniques for producing filaments, but are practically unusable in the following two points. For example, in the case of applications such as vegetation nets, insect nets, safety nets, sandbag nets, etc. that are used in a substantially natural environment for six months to several years, it is necessary to maintain the shape and physical properties (strength) during the use period. With the conventional technology, the strength due to resin degradation starts to decrease in several months to one year,
It cannot be practically used for such applications. Also, the secondary workability in forming the monofilament into a net, fish net, or rope shape is poor. For example, there is a case where yarns are entangled due to static electricity due to friction between a filament and a roll, a hook, a leg of a knitting machine or the like, and cannot be formed, or the filament is damaged or cut. Further, the device may be damaged by frictional wear.

[0007] With respect to the decrease in strength due to the deterioration of the resin, the durability can be improved by adding a conventionally known ultraviolet absorber, for example, a benzophenone ultraviolet absorber or a benzotriazole ultraviolet absorber. A technique for improving (weather resistance) is known (JP-A-9-233956). However, depending on the type of these absorbents, resin degradation may occur during melt-spinning, and the secondary workability when forming into nets, fish nets, and ropes as described above is not good, and above all, decomposition There is a problem that safety is impaired by the residue afterwards.

[0008]

As described above, in the prior art, there is no technique for obtaining a biodegradable filament having excellent durability (weather resistance) and simultaneously improved secondary workability. It is a fact. Accordingly, an object of the present invention is to provide a biodegradable monofilament having excellent durability (weather resistance) and improved secondary workability.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, by adding a specific inorganic filler to a lactic acid-based resin, the secondary workability and durability (weather resistance) have been improved. Has been found to be able to be improved, and the present invention has been completed. That is, the present invention is the invention described in the following [1] to [5]. [1] 100 parts by weight of lactic acid-based resin, carbon-based filler
A lactic acid-based resin monofilament which is obtained by melt-spinning a lactic acid-based resin composition comprising 005 to 10 parts by weight and has excellent secondary workability and weather resistance. [2] The monofilament excellent in secondary workability and weather resistance of [1], wherein the carbon-based filler is carbon black. [3] The lactic acid-based resin is polylactic acid [1] or [2].
Monofilament with excellent secondary workability and weather resistance. [4] The lactic acid resin monofilament excellent in secondary workability and weather resistance according to [1], wherein the lactic acid resin monofilament is provided with a lipophilic lubricant. [5] The lactic acid-based resin monofilament has a tensile strength of 2.
A lactic acid-based resin monofilament excellent in secondary workability and weather resistance according to [1] to [4], which has a tensile elongation of 0 to 10.0 g / d and a tensile elongation of 5.0 to 50%.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. [Lactic acid-based resin] In the present invention, the term "lactic acid-based resin" refers to a homopolymer or a copolymer in which the lactic acid component in all monomer components constituting the resin is at least 50% by weight or more. Copolymer of aliphatic hydroxycarboxylic acid (eg, copolymer of lactic acid and glycolic acid, copolymer of lactic acid and caproic acid, block copolymer of polylactic acid and polycaproic acid, etc.), copolymer of lactic acid and aliphatic polyhydric alcohol and aliphatic polycarboxylic acid (E.g., copolymers of lactic acid and butanediol with succinic acid and adipic acid, lactic acid and ethylene glycol, and copolymers of butanediol and succinic acid, block copolymers of polylactic acid and polybutylene succinate, and the like), and mixtures thereof. . Further, a mixture of polylactic acid and an aliphatic polyester (for example, polycaproic acid, polybutylene succinate, polyethylene succinate, a copolymer of β-hydroxybutyric acid and β-hydroxyvaleric acid, etc.) is included. In the case of a mixture, a compatibilizer may be contained. When the lactic acid-based resin is a copolymer, the mode of arrangement of the copolymer may be any mode such as a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer. Furthermore, these are at least partially xylylene diisocyanate, polyvalent isocyanates such as 2,4-tolylene diisocyanate and cellulose,
It may be cross-linked with a cross-linking agent such as a polysaccharide such as acetyl cellulose or ethyl cellulose, and at least a part thereof is linear, cyclic, branched, star-shaped, three-dimensional network structure, or any structure such as a three-dimensional network structure. Well, there are no restrictions.

[0011] In the lactic acid resin of the present invention, polylactic acid,
In particular, poly-L-lactic acid, a block copolymer of polylactic acid and poly-6-hydroxycaproic acid, particularly a block copolymer of poly-L-lactic acid and poly-6-hydroxycaproic acid, and a block of polylactic acid and polybutylene succinate Copolymers, especially block copolymers of poly-L-lactic acid and polybutylene succinate, block copolymers of polylactic acid, β-hydroxybutyric acid and β-hydroxyvaleric acid,
Particularly, a block copolymer of poly-L-lactic acid, β-hydroxybutyric acid and β-hydroxyvaleric acid is preferred.

[Aliphatic hydroxycarboxylic acid] Specific examples of the aliphatic hydroxycarboxylic acid constituting the lactic acid resin in the present invention include, for example, glycolic acid, lactic acid,
-Hydroxy drank acid, 4-hydroxy drank acid, 3-hydroxy valeric acid, 4-hydroxy valeric acid, 5-hydroxy valer lactic acid, 6-hydroxy caproic acid and the like. These may be one kind or a mixture of two or more kinds. When the aliphatic hydroxycarboxylic acid has an asymmetric carbon,
L-form, D-form, and a mixture thereof, that is, a racemic form may be used.

[Aliphatic polycarboxylic acid and its anhydride]
Specific examples of the aliphatic polycarboxylic acid constituting the lactic acid-based resin in the present invention, for example, oxalic acid, succinic acid,
Malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanoic acid,
Examples thereof include aliphatic dicarboxylic acids such as dodecane diacid and anhydrides thereof. These may be one kind or a mixture of two or more kinds.

[Aliphatic polyhydric alcohol] Specific examples of the aliphatic polyhydric alcohol constituting the lactic acid resin in the present invention include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 3-butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-
Nonanediol, neopentyl glycol, tetramethylene glycol, 1,4-cyclohexanedimethanol and the like can be mentioned. These may be one kind or a mixture of two or more kinds.

[Polysaccharides] Specific examples of polysaccharides include, for example, cellulose, cellulose nitrate, cellulose acetate, methylcellulose, ethylcellulose, celluloid, viscose rayon, regenerated cellulose, cellophane, cupra, cuprammonium rayon, cuprophan, bemberg , Hemicellulose, starch, amylopectin, dextrin, dextran, glycogen, pectin, chitin, chitosan, gum arabic, guar gum, locust bean gum, acacia gum, and the like, and derivatives thereof, with acetyl cellulose and ethyl cellulose being particularly preferred. Used. These may be one kind or a mixture of two or more kinds.

[Molecular weight of lactic acid-based resin] The molecular weight of the lactic acid-based resin used in the present invention is not particularly limited as long as it exhibits substantially sufficient mechanical properties. The average molecular weight is preferably from 1 to 3,000,000, more preferably from 3 to 2,000,000, and from 5 to 100
Is more preferable, 70,000 to 500,000 is still more preferable, and 9 to 500,000 is more preferable.
300,000 is most preferred. In general, when the weight average molecular weight is less than 10,000, mechanical properties are not sufficient. On the contrary, when the molecular weight is more than 3,000,000, handling becomes difficult due to molding processing, and uneconomical in production cost. It may be.

The weight average molecular weight and the molecular weight distribution of the lactic acid resin used in the present invention are determined by
Solvent type, catalyst type and amount, reaction temperature, reaction time,
The desired conditions can be controlled by appropriately selecting the reaction conditions such as the method of embedding the solvent distilled off by azeotropic distillation and the degree of solvent drying in the reaction system.

[Method for Producing Lactic Acid Resin] The method for producing the lactic acid resin of the present invention is not particularly limited. For example, as an example of a method for producing polylactic acid and a lactic acid-based resin having lactic acid as a structural unit, a method as described in Production Example 2 described below with reference to the method disclosed in Japanese Patent Application Laid-Open No. 6-65360 is disclosed. No. That is, lactic acid and / or an aliphatic hydroxycarboxylic acid other than lactic acid, or an aliphatic diol and an aliphatic dicarboxylic acid, in the presence of an organic solvent and a catalyst,
This is a direct dehydration condensation method in which dehydration condensation is performed as it is.

As another example of a method for producing a lactic acid-based resin having lactic acid as a structural unit, see, for example, JP-A-7-17326.
No. 6, reference is made to the method disclosed in JP-A-6-No. That is, this is a method in which a homopolymer of at least two kinds of lactic acid-based resins is copolymerized and transesterified in the presence of a polymerization catalyst.

As another example of the method for producing polylactic acid, for example, a method as shown in Production Example 1 described below with reference to the method disclosed in US Pat. No. 2,703,316 can be mentioned. . That is, it is an indirect polymerization method in which lactic acid and / or a hydroxycarboxylic acid other than lactic acid is once dehydrated into a cyclic dimer, and then subjected to ring-opening polymerization.

[Carbon-based filler] In the present invention, by adding a carbon-based filler to a lactic acid-based resin, it is possible to improve the secondary workability and durability of the filament while maintaining biodegradability and environmental adaptability. it can. Specific examples of the carbon-based filler include carbon black, charcoal, mica, activated carbon, carbon fiber, whiskers of carbon fiber, and the like, and carbon black is particularly preferred.

The carbon black is referred to as furnace black, channel black, thermal, etc., depending on the production method, and gas black, oil black, acetylene black, etc., depending on the raw material.
Furnace for rubber / ECF, Furnace for rubber / SC
F, Furnace for rubber, CF, Pyrolytic carbon, EF,
Soft carbon / acetylene and the like can be mentioned. Specific examples of furnace black include, for example, Ketjen Black EC (trade name, manufactured by Akzo, The Netherlands), Vulcan XC72 (trade name, manufactured by CABOT, USA), Asahi HS-
500 (trade name, manufactured by Asahi Carbon Co., Ltd.) and the like. .
As the carbon fiber, for example, an acryl fiber firing system, a pitch system, and the like can be given.

[Particle Size of Carbon-Based Filler] The particle size of the carbon-based filler must be appropriately selected depending on the shape and diameter of the filament, but is generally preferably 1 nm to 100 μm, more preferably 3 nm to 75 μm. 5 nm to 50 μ
m is more preferred, and 10 nm to 10 μm is most preferred. Such carbon-based fillers include, for example, Raven 5 manufactured by Columbian Carbon Japan Co., Ltd.
00, Raven 1000, Raven 1190U
LTRA, Raven 2000, Raven 350
0, Raven5000 ULTRA, Raven
7000 and the like. In particular, R
aven 1190 ULTRA is preferred.

[Addition amount of carbon-based filler] The addition amount of the carbon-based filler depends on the kind thereof, but does not extremely impair the mechanical strength of the filament and the biodegradability. ) And secondary workability are not limited at all. Generally, 0.005 to 10 parts by weight can be added to 100 parts by weight of the lactic acid-based resin, preferably 0.01 to 5 parts by weight, more preferably 0.05 to 5 parts by weight.
-3 parts by weight, more preferably 0.1-1 part by weight.
If the amount is less than 0.005 parts by weight, the effect of the addition will not be exhibited, and if it is more than 10 parts by weight, the mechanical properties of the filament may deteriorate.

[Additives] The lactic acid-based resin composition of the present invention may be used in an amount that does not impair the mechanical strength of the filament, the secondary workability of forming into a net, a fish net, or a rope, and the safety and biodegradability. If present, various elastomers (SBR, NBR, SBS type ternary block copolymer thermoplastic elastomer, etc.) and additives (plasticizer, pigment, stabilizer, antistatic agent, ultraviolet absorber, antioxidant, flame retardant,
Release agents, lubricants, dyes, antibacterial agents) and impact modifiers (impact core / shell type particles, impact modifiers, etc.) can be appropriately used depending on the purpose and application.

[Production method of lactic acid-based resin composition] In the present invention, a method of mixing, kneading and kneading a lactic acid-based resin, a carbon-based filler, and optionally other additives to form a lactic acid-based resin composition. Is a kneading technique known in the art, for example, a method of mixing the respective raw materials with a Henschel mixer, a ribbon blender, or the like, or kneading while directly adding to the molten polymer using an extruder or the like (side feed method).
Can be adopted.

[Molding of Lactic Acid Resin Monofilament] A method for producing a lactic acid resin monofilament will be described below. As a method for producing a lactic acid-based resin monofilament, for example, a lactic acid-based resin composition is extruded from a die hole of a molding machine and extruded into a cooling water tank to obtain a strand. A take-up winding step.

<Extrusion Step> The extrusion temperature is from the melting point (Tm) of the lactic acid-based resin composition to Tm + 50 ° C., and the molten strand coming out of the die is cooled in a cooling water bath. The water temperature is 20 to 80, depending on the diameter of the monofilament.
° C is preferred, the range of 30-70 ° C is more preferred, and the range of 40-60 ° C is even more preferred. Water temperature is 30 ℃
If it is lower than the lower limit, the strand becomes excessively hard, so that a running disturbance occurs in the strand or the disturbance propagates to the surroundings, thereby adversely affecting the shape of the strand. Also,
Disturbance in the shape of the strand may cause the next stretching to be not uniform. When the water temperature is higher than 80 ° C., insufficient cooling of the strand occurs, and the strand is introduced into the next stretching step while being soft, which may cause poor winding by the take-up roller (stretching roller).

<Stretching Step> The term "stretching" as used in the present invention refers to an operation of mechanically stretching a monofilament (yarn) at a temperature equal to or lower than the melting point of the material to orient molecules in a direction parallel to the tensile direction. This operation significantly increases the tensile strength and increases the toughness. After the stretching process, if the film is reheated to a temperature higher than the stretching temperature, it tends to shrink to its original size. To stabilize the dimensions and strength, heat treatment at a temperature slightly lower than the stretching temperature (heat fixing, heat setting) May be performed. In the present invention, the strand obtained in the extrusion step is stretched by heating to a specific temperature. Stretching is performed according to the speed ratio (stretching ratio) between the entrance-side take-up roller and the exit-side take-up roller.
Double is preferred. The heating method at the time of stretching may be any of a hot water tank, an oven, a hot roll and the like, and is not limited at all. However, a hot water tank is more preferable for more uniform heating and stretching.

Stretching using a hot water tank can be realized by arranging a water tank having a length and depth capable of adjusting the water temperature, and a take-up roller before and after the water tank. Stretching using an oven can be realized by arranging an electric heater (infrared heater) as a heat source in the longitudinal direction to adjust the temperature by arranging an oven having a length of several meters, and arranging a take-off roller before and after the oven. . In addition, stretching using a hot roll is realized by installing a plurality of heated and temperature-controlled take-off rollers with water pipes, oil pipes, electric heaters, etc. arranged inside, and adjusting the rotation speed of the rolls. It is possible.

In the present invention, the temperature conditions during stretching are as follows:
Regardless of which apparatus or method is selected, such as a hot water tank, an oven, and a hot roll, the surface temperature of the filament before stretching is from the glass transition temperature (Tg) to the melting point (Tm) of the lactic acid-based resin composition. Is preferable, Tg to Tm-30 ° C is more preferable, and Tg to Tm-60 ° C is further preferable. If the surface temperature is lower than Tg, stretching breakage occurs,
In some cases, stretching three times or more becomes impossible. Conversely, when the temperature exceeds Tm, the effect of strength development by stretching is reduced.

In the present invention, the stretching ratio is usually in the range of 3 to 15 times, preferably 4 to 14, and more preferably 5 to 13 times. If the draw ratio is less than 3 times, the strength development by the drawing operation becomes insufficient, and a product having practical strength (2.0 g / d or more) as a filament may not be obtained. On the other hand, if the draw ratio exceeds 15 times, troubles such as easy breakage of the stretch, whitening due to voids, and vertical breakage of the filament may occur.

As a method for performing stretching of 3 to 15 times, 1
In addition to the method performed in stages, these are appropriately combined to obtain 2
It is also possible to adopt a method in which a three-stage to multi-stage structure is used, and a low-magnification stretching is performed in each stage so that the total stretching ratio is 3 to 15 times.

In the case of performing multi-stage stretching, the stretching ratio is sequentially changed, for example, from 1.1 to 10 times in the first stage and from 1.5 to 10 times in the second stage. Magnification 3
Preferably, the heating temperature condition is set to be the lowest at the first stage in the above-mentioned temperature range, and the temperature is sequentially increased each time the number of stages is increased.

In the present invention, the drawn filament is further heat-treated (heat-set) to suppress a change in physical properties (eg, shrinkage) at a high temperature. In the method, heat treatment is performed at a temperature between the glass transition temperature (Tg) and the melting point (Tm) of the lactic acid-based resin composition, preferably 70 to 120 ° C.
More preferably, it is guided to a heating tank set at 80 to 100 ° C., heat-treated (heat set), and then cooled in a cooling tank. As in the case of the stretching operation, any method such as a water tank, an oven, or a hot roll may be used for the heat treatment, and there is no limitation. Cooling may be performed by either water cooling or air cooling, and there is no limitation.

<Winding Step> Finally, the drawn filament is wound into a tubular paper, plastic, or metal winding by a winding machine to obtain a wound filament.

The monofilament obtained by the production method of the present invention has a draw ratio of 3 to 15 times, a filament thickness of 50 to 2000 d, and a tensile strength of 2.0 to 10.0 g measured according to JIS Z8703. / D, and a monofilament having a tensile elongation of 5 to 50%.

The monofilament obtained according to the present invention is excellent in durability (weather resistance), and is suitable for use in secondary processing into a net, fish net, or rope when used with rolls, hooks, and legs of a loom or knitting machine. It exhibits good formability and high productivity without causing yarn breakage or yarn entanglement due to wear or friction.

In the present invention, by applying a lipophilic lubricant to the surface of the monofilament, better secondary workability and higher productivity can be imparted. Examples of the method of applying a lipophilic lubricant to the surface of the monofilament of the present invention include (1) a method of melt-spinning a lactic acid-based resin composition obtained by further adding a lubricant to a lactic acid-based resin composition containing a carbon-based filler. And (2) a lubricant in any steps from an extrusion step of melt-spinning a lactic acid-based resin composition containing a carbon-based filler to obtain a strand, a stretching step of stretching the strand, and a winding step of winding the stretched yarn. Coating method.

In the case of the method (1), the lubricant bleeds out to the surface of the yarn in the above-mentioned extrusion step or drawing step, and the effect of the present invention is exhibited. Therefore, it is preferable that the lubricant has low compatibility with the lactic acid-based resin.

Examples of the lipophilic lubricant include spindle oil, refrigerator oil, compressor oil, dynamo oil, turbine oil, machine oil, engine oil, cylinder oil, marine engine oil, gear oil, aviation oil, jet engine And petroleum-based lubricating oils mainly containing working oils and hydraulic oils.

In particular, the kinematic viscosity of a petroleum-based lubricating oil is 1 at 40 ° C.
５００500 mm ² S is good, preferably 1-300 mm ²
/ S is good, more preferably 1 to 100 mm ² / S, and most preferably 1 to 50 mm ² / S. If the kinematic viscosity is greater than 500 mm ² / S, handling may be difficult, control of the amount of application when applying to the filament may be difficult, or uneconomical.

As such a petroleum-based lubricating oil, for example,
Product name of Idemitsu Kosan Co., Ltd., Diana Fresia G-
6, Diana Fresia W-8, Diana Fresia K
-8, Diana Fresia F-9, Diana Fresia
NR-9, Diana Fresia S-10, Diana Fresia S-32, Diana Fresia P-32), Diana Fresia P-90, Diana Fresia P-18
0, Diana Fresia P-430, Diana Fresia
N-28, Diana Fresia N-90, Diana Fresia N-150, Diana Fresia N-430, Diana Fresia U-46, Diana Fresia U-6
8, Diana Fresia U-130, Diana Fresia U-260 and the like. These may be one kind or a mixture of two or more kinds.

The secondary processed product shown in the present invention is, for example, a net shape processed by a conventionally known knitting machine or loom,
It has the shape of a rope, a net, or a combination thereof, and there are no restrictions on its size, shape, or design. The types of netting used when processing with knitting machines and looms include knotted nets such as mesh nets, frog nets, double frog nets, and nets such as Russell nets, maple nets, woven nets, and metallic fiber nets. There is no knot network, but there is no limitation.

The monofilament secondary product obtained by the present invention can be used for applications such as fishing materials, agricultural and forestry materials, civil engineering and construction materials, sports and leisure materials, and industrial materials. For example, as fishing materials,
Nori net, fishing line, bottoming net, gill net, trawl net, fixed net, winding net, fish net such as aquaculture net, aquaculture, rope for fishing boat, etc.
Materials for agriculture and forestry include insect-proof nets, wind-proof nets, shading nets, weed prevention nets, bird-proof nets, cue nets, flower nets, etc., and civil engineering and building materials include vegetation nets, sandbag nets, rockfall nets, Sports and leisure materials such as safety nets include golf, baseball, tennis, table tennis, volleyball, badminton, soccer, handalls, basketball, hockey, ice hockey, water polo and other sport nets, insect nets, and the like.

[0046]

[Examples] Production examples, examples and comparative examples are shown below.
The present invention will be described in detail. Note that descriptions of synthesis examples, examples, comparative examples, aspects and the like in the specification of the present application are descriptions for assisting understanding of the contents of the present invention, and the description narrows the technical scope of the present invention. It is not of a nature to be interpreted.

The method for producing the polylactic acid resin used in the examples and comparative examples is described below. All parts in the text are based on weight. The average molecular weight (weight average molecular weight Mw) of the polymer was measured by gel permeation chromatography using polystyrene as a standard under the following conditions. Equipment: Shimadzu LC-IOAD Detector: Shimadzu RID-6A Column: Hitachi Chemical GL-S350DT-5, GL-S3
70DT-5 Solvent: chloroform Concentration: 1% Injection volume: 20 μl

Further, the glass transition temperature (Tg) and the melting point (Tm) are measured by a differential scanning calorimeter (manufactured by Shimadzu Corporation;
SC-50), the point at which the lactic acid-based resin changes into a rubbery state when the temperature is raised at a rate of 10 ° C./min is defined as a glass transition point (T
g), the peak of the melting peak was taken as the melting point (Tm).

Production Example 1 <Production of Polymer A (Poly L-lactide)> 100 parts by weight of L-latatide and stannous octoate 0.1%
01 parts and 0.03 parts of lauryl alcohol were sealed in a thick cylindrical stainless steel polymerization vessel equipped with a stirrer, degassed under vacuum for 2 hours, and then replaced with nitrogen gas. The mixture was heated at 200 ° C. for 3 hours with stirring under a nitrogen atmosphere. While maintaining the temperature as it was, the air was gradually degassed by a vacuum pump through an exhaust pipe and a glass receiver, and the pressure inside the reaction vessel was reduced to 3 mmHg. One hour after the start of degassing, the distillation of the monomer and low-molecular-weight volatiles disappeared. Therefore, the inside of the vessel was replaced with nitrogen, and the polymer was drawn out from the lower part of the vessel in the form of a strand, pelletized, and homopolymer of L-lactide (polymer A) was obtained. The yield was 78% and the weight average molecular weight Mw was 136,000. The glass transition temperature (Tg) of this polymer is 58 ° C. and the melting point (Tm) is 1
75 ° C.

Production Example 2 <Polymer B (poly L-lactic acid)
Production of 10% of 90% L-lactic acid at 150 ° C./5 in a 100-liter reactor equipped with a Dien-Stark trap
After distilling water while stirring at 0 mmHg for 3 hours, 6.2 g of tin powder was added, and the mixture was further added at 150 ° C / 30 mmHg for 2 hours.
Stir for hours to oligomerize. 28.8 g of tin powder and 21.1 kg of diphenyl ether were added to this oligomer,
An azeotropic dehydration reaction at 150 ° C./35 mmHg was performed, and the distilled water and the solvent were separated by a water separator, and only the solvent was returned to the reactor. Two hours later, the organic solvent to be returned to the reactor was passed through a column packed with 46 kg of molecular sieve 3A, and then returned to the reactor. A solution of polylactic acid was obtained. Diphenyl ether 44 dehydrated in this solution
After adding kg and diluting, the mixture was cooled to 40 ° C., and the precipitated crystals were filtered, washed three times with 10 kg of n-hexane, and dried at 60 ° C./50 mmHg. 0.5 N of this powder
-Add 12 kg of HCl and 12 kg of ethanol, and add 35
After stirring at 1 ° C. for 1 hour, the mixture was filtered and dried at 60 ° C./50 mmHg to obtain 6.1 kg of white polylactic acid (yield: 85%).
%). The weight average molecular weight Mw of this polylactic acid (Polymer B) was 145,000. Tg of this polymer
Was 58 ° C and Tm was 168 ° C.

Production Example 3 <Production of polymer C (polybutylene succinate / polylactic acid copolymer)> 50.5 g of 1,4-butanediol and 66.5 of succinic acid
g to 293.0 g of diphenyl ether and 2.02 to tin metal
g was added thereto, and the mixture was heated and stirred at 130 ° C./140 mmHg for 7 hours while distilling water out of the system to form an oligomer. to this,
Attach Dean-Stark trap, 140 ° C
After azeotropic dehydration at 30 mmHg for 8 hours, a tube filled with 40 g of molecular sieve 3A was attached, and the distilled solvent was returned to the reactor through the molecular sieve tube, and stirred at 130 ° C / 17 mmHg for 49 hours. did. The reaction mass was dissolved in 600 ml of chloroform, added to 4 liters of acetone and reprecipitated, and then a solution of HCl in isopropyl alcohol (hereinafter abbreviated as IPA) (H
(Cl concentration: 0.7 wt%) for 0.5 hour (three times), washed with IPA, and dried under reduced pressure at 60 ° C. for 6 hours to obtain polybutylene succinate. The weight average molecular weight Mw of this polymer was 138,000.

40. Polybutylene succinate obtained
0 g of polylactic acid 16 obtained by the same method as in Production Example 2.
0.0 g (weight average molecular weight Mw is 2,000,000), 800 g of diphenyl ether and 0.7 g of metal tin were mixed, and
The dehydration condensation reaction was performed at 30 ° C./17 mmHg for 20 hours. After completion of the reaction, post-treatment was carried out in the same manner as in Production Example 2 to give a copolymer 188 of polybutylene succinate and polylactic acid.
g (94% yield). This block copolymer of polybutylene succinate and polylactic acid (copolymer C)
Had a weight average molecular weight Mw of 14,000. This polymer had a Tg of 55 ° C and a Tm of 162 ° C.

Production Example 4 <Production of polymer D (polycaproic acid / polylactic acid copolymer)> Same as Production Example 3 except that 6-hydroxycaproic acid was used instead of 1,4-butanediol and succinic acid. As a result, polycaproic acid (91% yield) was obtained. The weight average molecular weight Mw of this polymer was 158,000. To 40.0 g of the obtained polycaproic acid, 160.0 g of a polylactic acid obtained by the same method as in Production Example 2 (weight average molecular weight Mw is 20,000), and diphenyl ether 800
g, 0.7 g of metallic tin, and again 130 ° C./17 mm
A dehydration condensation reaction was performed at Hg for 20 hours. After the reaction, post-treatment was carried out in the same manner as in Production Example 2 to obtain 192 g of a copolymer of polycaproic acid and polylactic acid (96% yield). The weight average molecular weight Mw of the block copolymer (copolymer D) of polycaproic acid and polylactic acid was 150,000. This polymer had a Tg of 56 ° C and a Tm of 158 ° C.

Production Example 5 <Production of Polymer E (Copolymer of β-hydroxybutyric acid and β-hydroxyvaleric acid / polylactic acid copolymer)> Biopol D was used as a copolymer of β-hydroxybutyric acid and β-hydroxyvaleric acid. To 40.0 g of -311G (trade name, manufactured by Monsanto Co.), 160.0 g of polylactic acid obtained by the same method as in Production Example 2 (weight average molecular weight Mw is 2.
0,000), 800 g of diphenyl ether, 0.7 g of metal tin
, And again subjected to a dehydration condensation reaction at 130 ° C./17 mmHg for 20 hours. After completion of the reaction, post-treatment was carried out in the same manner as in Production Example 2 to obtain 190 g (yield: 95%) of a copolymer of β-hydroxybutyric acid and β-hydroxyvaleric acid and a copolymer of polylactic acid. The weight average molecular weight Mw of the block copolymer (copolymer E) of this copolymer of β-hydroxybutyric acid and β-hydroxyvaleric acid and polylactic acid is 1
It was 47,000. The Tg of this polymer is 55 ° C., Tm
Was 157 ° C.

[Evaluation of Physical Properties] The conditions for evaluating the physical properties of the monofilaments produced in Examples and Comparative Examples using the lactic acid-based resins obtained in Production Examples 1 to 5 are as follows. (1) Mechanical strength According to JIS Z8703, tensile speed 300 mm / mi
The tensile strength and the elongation were measured at m and a distance between spans of 200 mm.

(2) Secondary Workability The workability when the monofilament was formed into a net shape by a knitting machine using a netting type of Russell net was evaluated for the following items. * The occurrence of thread entanglement ◎: Thread entanglement does not occur and molding is possible. ○: The thread is not entangled and molding is possible. ×: Thread entanglement occurs and molding is difficult. * Thread breakage occurrence ◎ … Suitable for forming without thread breakage 〇… Suitable for forming without thread breakage ×… Difficult to form due to thread breakage

(3) Durability (Weather Resistance) Test The filament was left outdoors for one year in accordance with the outdoor exposure test JIS K-7219. The weight average molecular weight and mechanical strength of the filament before and after the test were examined, and the molecular weight retention (%) and the strength retention (%) were determined according to the following equations. Molecular weight retention (%) = (weight average molecular weight after test / weight average molecular weight before test) × 100 Strength retention (%) = (strength value after test / strength value before test) × 100

Example 1 Polymer A100 obtained in Production Example 1 as a lactic acid-based resin
Parts by weight, Raven 1190 U as carbon-based filler
LTRA (trade name, manufactured by Columbia Carbon Japan)
(A) After sufficiently mixing 0.5 parts by weight with a Henschel mixer, the cylinder set temperature of the twin-screw extruder is set to 170 to
Pelletized at 190 ° C. This pellet is heated at 80 ° C /
After drying for 4 hours, 90 strands were extruded with a cylinder set temperature of an extruder equipped with a gear pump at 170 to 200 ° C. and a die hole diameter of 1.5 mm, and placed in a water tank set at 45 ° C. provided immediately below the die. It was guided and cooled to obtain a strand. The obtained strands are introduced into two water tanks set at a temperature of 60 to 80 ° C. and 90 to 100 ° C. as first and second heating tanks for drawing, and by a speed ratio of a drawing roller arranged before and after each water tank, respectively. Were set to 5.0 times and 2.5 times. Subsequently, the atmosphere temperature near the surface of the filament was guided to an oven set at 100 ° C., and heat treatment (heat fixing) was performed. Then, the filament was cooled in a cooling water bath adjusted to a water temperature of 30 ° C., and the heat-treated filament was further cooled. After passing through a tank containing Dynafrecia W-8 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) as a lubricant, it was wound around a paper roll by a winder.

The moldability at this time was good without breaking the yarn during stretching or winding. The obtained filament had a thickness of 500 d, a tensile strength of 7.0 g / d, and a tensile elongation of 25%. A storage test was performed at 40 ° C. for 3 months with the obtained filament wound on a paper roll. As a result, there was no change in both appearance and strength. Next, the obtained filament was knitted in a net shape by a knitting machine using a netting type of Russell net as a type of netting. As a result, it was possible to form well without causing entanglement or yarn breakage. According to the outdoor exposure test JIS K-7219, the obtained filament had a molecular weight retention of 91% and a strength retention of 92% when left outdoors for one year.

Examples 2 to 11 Filaments were produced in the same manner as in Example 1 except that the types and amounts of the lactic acid-based resin and the carbon-based filler, the type of the lubricant, and the first and second draw ratios during stretching were changed. It was manufactured and its physical properties were evaluated. The results are shown in Table 1 (Table 1, Table 2, Table 3). The carbon fillers and lubricants used are as follows. Carbon-based filler A: Raven 1190 ULTRA (trade name, manufactured by Columbia Carbon Japan) B: Raven 7000 (trade name, manufactured by Columbia Carbon Japan) C: Raven 410 (trade name, manufactured by Columbia Carbon Japan) Lipophilic lubricant A: Dyna Fresia W-8 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) B: Dyna Fresia F-9 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) C: Dyna Fresia S-32 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) ) D: Dyna Fresia U-68 (trade name, manufactured by Idemitsu Kosan Co., Ltd.)

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

[Table 3]

Comparative Examples 1 to 5 Filaments were produced in the same manner as in Example 1 except that the carbon-based filler and the lubricant were not used, the lactic acid-based resin, and the first and second stretching magnifications during stretching were changed. And physical properties were evaluated. The results are shown in Table 2 (Table 4).

[0065]

[Table 4]

[0066]

Industrial Applicability The lactic acid-based resin monofilament of the present invention does not impair biodegradability, has excellent secondary workability when formed into a net, fishnet, or rope shape, and has durability when used in a natural environment. Has excellent physical properties (weather resistance).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D01F 6/62 302 D01F 6/62 302E 305 305Z // D06M 13/02 D06M 13/02 (72) Inventor Yasuhiro Kitahara 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsui Chemicals Co., Ltd. 1190 Kasama-cho Mitsui Chemical Co., Ltd. (72) Inventor Tomoyuki Nakata 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa F-term (reference) 4J029 AA01 AA05 AB01 AC02 AE02 EA05 HA01 HB01 4L033 AA06 AB01 AC15 BA01 4L035 BB57 BB59 BB91 DD14 EE08 EE 20 FF01 FF02 JJ10

Claims (5)

[Claims] 1. A lactic acid-based resin obtained by melt-spinning a lactic acid-based resin composition comprising 100 parts by weight of a lactic acid-based resin and 0.005 to 10 parts by weight of a carbon-based filler, and having excellent secondary workability and weather resistance. Monofilament. 2. The monofilament excellent in secondary workability and weather resistance according to claim 1, wherein the carbon-based filler is carbon black. 3. The monofilament excellent in secondary workability and weather resistance according to claim 1, wherein the lactic acid-based resin is polylactic acid. 4. The lactic acid-based resin monofilament according to claim 1, wherein the lactic acid-based resin monofilament is provided with a lipophilic lubricant. 5. The lactic acid-based resin monofilament has a tensile strength of 2.0 to 10.0 g / d and a tensile elongation of 5.0 to 50%.
The lactic acid-based resin monofilament excellent in secondary workability and weather resistance according to claim 1.