JP2008000046A - Cord for cord-type bush cutter composed of biodegradable resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cord for a cord-type bush cutter ensuring safety in the use of the cord-type bush cutter, causing the decomposition of the cord in natural environment even in the case of the breakage, falling or flying of the cord and having necessary cutting performance. <P>SOLUTION: The cord for a cord-type bush cutter is made of a biodegradable resin having a tensile elastic modulus of ≥10 MPa and ≤1,000 MPa at 23°C in conformity to JIS K7127. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cord used for a cord-type mower having biodegradability.

  Conventionally, a rotating metal blade has been attached as a part for cutting a grass mower. However, there is a risk of damaging it when it comes into contact with a leg or the like when handling the cord mower as shown in FIG. It has been developed. In this case, instead of a metal blade, a nylon cord 12 is used as a cutting part for a rotating plate 11 connected to a handle 14 by a handle 13, and the cord 12 is rotated to wipe out the grass. Even if it contacts the leg of the human body by mistake, the mass and cutting force are smaller than those of the metal blade, so that serious injury can be avoided even if it contacts the human body.

  This nylon cord is excellent in strength and has a sufficient cutting force as a mower, but there is still no possibility that the cord itself will be cut during use. However, since this nylon cord hardly decomposes in nature, if the cut cord falls off or scatters, it may be left semi-permanently, and it is difficult to say that it is an excellent material from the viewpoint of environmental protection.

  On the other hand, the resin-made rotary mowing blade containing biodegradable resin or photodegradable resin like the patent document 1 is proposed. Such a resin-made rotary mowing blade is excellent from the viewpoint of environmental protection, even if the blade is chipped and the fragments are scattered, the fragments are decomposed in nature.

  Further, as a cord used for a cord type mower, a monofilament used for a mower obtained by extruding a material made of a biodegradable resin such as polylactic acid, drawing processing, and further heat processing is disclosed in Patent Document 2. It is disclosed. Even if the cord is cut or scattered, the cut portion is decomposed in the natural world, which is similarly excellent from the viewpoint of environmental protection.

Japanese Patent Laid-Open No. 7-184446 JP 2002-105750 A

  However, since the resin rotary grass cutting blade described in Patent Document 1 has a cutting force close to that of a metal blade, it is similarly dangerous to handle and may cause serious injury when it comes into contact with the human body.

  Among the monofilaments described in Patent Document 2, monofilaments obtained by processing a hard resin such as polylactic acid among biodegradable resins have a too high tensile elastic modulus. There was a risk of serious injury when touching the human body.

  Furthermore, Patent Document 2 describes a method of softening by blending a plasticizer, but when blending a plasticizer, the crystallization speed is improved and the plasticizer bleeds out of the molded body. Since the degree of crystallinity of the biodegradable resin is improved, the rigidity is improved with the passage of time, and in some cases, the strength becomes dangerous.

  Therefore, the present invention provides a cord used for a cord-type mower that ensures safety during use and is decomposed in the natural environment even when cut, dropped or scattered, and is excellent in terms of environmental protection. The purpose is to do.

  The present invention solves the above problems by a cord used in a cord type mower made of a biodegradable resin having a tensile elastic modulus at 23 ° C. of 10 MPa or more and 1000 MPa or less based on JIS K7127.

  The cord used for the cord type mower according to the present invention uses the biodegradable resin having the above elastic modulus to ensure safety when using the mower and to have a sufficient cutting force. Become. Moreover, since it consists of biodegradable resin, when it cut | disconnects, drops | omits, and disperses, it decomposes | disassembles in a natural environment and becomes a code | cord | chord used for the cord type mower excellent also from the viewpoint of environmental protection.

Hereinafter, the present invention will be described in detail.
The present invention is a cord used for a cord type mower made of a biodegradable resin having a tensile elastic modulus at 23 ° C. in a predetermined value range based on JIS K7127. As shown in FIG. 1, the cord-type mower is a mower that cuts the grass by the cord 12 extending outward from the rotating disk hitting the surrounding grass with the rotation of the rotating disk 11.

  The tensile elastic modulus needs to be 10 MPa or more, preferably 100 MPa or more, and more preferably 200 MPa or more. If it is less than 10 MPa, it will be almost impossible to cut even if it hits the grass, and even if it is used in a mower, the function as a mower cannot be fully exhibited. On the other hand, it is necessary to be 1000 MPa or less, preferably 900 MPa or less, and more preferably 800 MPa or less. If the pressure exceeds 1000 MPa, the rigidity is too high, and contact with the human body during rotation may cause safety concerns such as serious injury to the body.

  Examples of such biodegradable resins include aliphatic polyesters other than polylactic acid, aromatic aliphatic polyesters, and polyesters of diol, dicarboxylic acid, and lactic acid. One kind selected from these, or A plurality of types of biodegradable resin compositions may be used.

  Examples of the aliphatic polyester include polyhydroxycarboxylic acids other than polylactic acid, aliphatic polyesters obtained by condensing aliphatic diols and aliphatic dicarboxylic acids, and aliphatic polyesters obtained by ring-opening polymerization of cyclic lactones. And synthetic aliphatic polyesters. The term “other than polylactic acid” means that D-lactic acid, L-lactic acid, or polylactic acid composed only of both of them is not included, and the aliphatic polyester having a lactic acid unit as a part of the structural unit is Including. This is because polylactic acid composed only of lactic acid has an excessively high tensile elastic modulus and exceeds 1000 MPa, so that it is not preferable as a biodegradable resin alone.

  Examples of the “polyhydroxycarboxylic acid” include 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, Examples include homopolymers and copolymers of hydroxycarboxylic acids such as 2-methyl lactic acid and 2-hydroxycaproic acid.

  As the above “aliphatic polyester obtained by condensing an aliphatic diol and an aliphatic dicarboxylic acid”, for example, one type or two or more types are selected from the following aliphatic diols and aliphatic dicarboxylic acids. A polymer that can be condensed or obtained by jumping up the condensed product with an isocyanate compound or the like as required can be exemplified.

  Here, examples of the “aliphatic diol” include ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, and the like. Examples of the “aliphatic dicarboxylic acid” include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid.

  Examples of the cyclic lactones used in the above “aliphatic polyester obtained by ring-opening condensation of cyclic lactones” include ε-caprolactone, δ-valerolactone, β-methyl-δ-valerolactone, which are cyclic monomers, and the like. The aliphatic polyester can be obtained by polymerizing one or more of these cyclic monomers.

  Examples of the “synthetic aliphatic polyester” include polyesters of cyclic acid anhydrides and oxiranes. Examples of the oxiranes include succinic anhydride, ethylene oxide, and propion oxide.

  Specific examples of the above aliphatic polyester include polybutylene succinate obtained by ester polymerization of succinic acid and 1,4 butanediol, and ester of succinic acid, 1,4 butanediol and adipic acid. Polymerized polybutylene succinate adipate can be mentioned, and examples of the product include “Bionore” series manufactured by Showa Polymer Co., Ltd. In addition, “Cell Green” series manufactured by Daicel Chemical Industries, Ltd. obtained by ring-opening condensation of ε-caprolactone is commercially available.

  Moreover, as said aromatic aliphatic polyester used as another biodegradable resin composition in this invention, what reduced crystallinity by introduce | transducing an aromatic ring between aliphatic chains is mentioned. For example, it can be obtained by condensing an aromatic dicarboxylic acid component, an aliphatic dicarboxylic acid component, and an aliphatic diol component.

  Here, examples of the aromatic dicarboxylic acid component include isophthalic acid, terephthalic acid, and 2,6-naphthalenedicarboxylic acid. Examples of the aliphatic dicarboxylic acid component include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid. Furthermore, examples of the aliphatic diol component include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, and the like. Two or more of these aromatic dicarboxylic acid components, aliphatic dicarboxylic acid components, or aliphatic diol components may be used.

  In the present invention, the aromatic dicarboxylic acid component most preferably used is terephthalic acid, the aliphatic dicarboxylic acid component is adipic acid, and the aliphatic diol component is 1,4-butanediol. It is done. All of these are preferable because they are easily available industrially and commercially. The above aromatic aliphatic polyester obtained from these becomes polybutylene adipate terephthalate.

  Examples of the above aromatic aliphatic polyester include, in addition to the above, a condensate of tetramethylene adipate and terephthalate, a condensate of polybutylene adipate and terephthalate, and the like. Among these, as a condensate of tetramethylene adipate and terephthalate, for example, “Eastar Bio” manufactured by Eastman Chemicals is commercially available. As a condensate of polybutylene adipate and terephthalate, “Ecoflex” manufactured by BASF is commercially available.

  Further, the polyester of diol, dicarboxylic acid and lactic acid used as another biodegradable resin composition in the present invention includes an ester polymerization portion by diol and dicarboxylic acid, and a lactic acid polymerization portion in which lactic acid is ester-polymerized. It is mixed in one polymer.

  The mixing method includes a random polymer in which diol, dicarboxylic acid, and lactic acid are randomly polymerized, and a block-like heavy polymer in which a polymerization portion of diol and dicarboxylic acid and a polymerization portion that is polylactic acid appear alternately in the main chain. Examples thereof include a graft polymer in which one of a polymerized portion of a polymer, a diol and a dicarboxylic acid and a polymerized portion of polylactic acid forms a main chain and the other is connected as a side chain. Among these, it is more preferable to use a block polymer or a graft polymer because the impact resistance improving effect and transparency are particularly high. Specific examples of the random polymer include “GS Pla” series manufactured by Mitsubishi Chemical Corporation. Specific examples of the block polymer or graft polymer include “Plamate” series manufactured by Dainippon Ink & Chemicals, Inc.

  In the polymer having the ester polymerized part and the lactic acid polymerized part, the ratio of the lactic acid polymerized part is preferably 10% by mass or more, and more preferably 20% by mass or more. This is because the heat resistance may be insufficiently maintained when the content is less than 10% by mass. On the other hand, it is preferably 80% by mass or less, and more preferably 70% by mass or less. If it exceeds 80% by mass, the impact resistance imparting effect will be insufficient, and in order to obtain a clearer effect, the content is preferably 70% by mass or less.

  A method for producing a polymer having an ester polymerized part and a lactic acid polymerized part is not particularly limited, but a polyester or polyether polyol having a structure in which a diol and a dicarboxylic acid are dehydrated and condensed is opened with lactide. Method obtained by ring polymerization or transesterification, polyester having a structure obtained by dehydration condensation of diol and dicarboxylic acid, or dehydration / deglycolization condensation or transesterification of polyether polyol with lactic acid resin The method of obtaining etc. are mentioned.

  The diol used here is not particularly limited, but ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-pep Linear diols such as tandiol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, propylene glycol, 1,2 -Butanediol, 1,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,2- Branching of hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, etc. Jo-diol, polyethylene glycol, polypropylene glycol, polybutylene glycol, polyols and polytetramethylene glycol.

  In addition, the dicarboxylic acid used herein is not particularly limited, but succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, maleic acid, fumaric acid, citraconic acid, Linear dicarboxylic acids such as dodecanedicarboxylic acid and cyclohexanedicarboxylic acid, methylsuccinic acid, dimethylsuccinic acid, ethylsuccinic acid, 2-methylglutaric acid, 2-ethylglutaric acid, 3-methylglutaric acid, 3-ethylglutaric acid, 2 -Branched dicarboxylic acids such as methyl adipic acid, 2-ethyl adipic acid, 3-methyl adipic acid, 3-ethyl adipic acid, methyl glutaric acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, naphthalenedicarboxylic acid , Phthalic anhydride, bisphenol A, biffe And an aromatic dicarboxylic acid such Lumpur.

  The polyester of diol, dicarboxylic acid, and lactic acid can be further adjusted to a predetermined molecular weight by cross-linking molecules using an isocyanate compound or a carboxylic acid anhydride. However, the molecular weight after adjustment is preferably 50,000 or more, and more preferably 100,000 or more. This is because if the molecular weight is less than 50,000, the durability is insufficient and there is a high possibility that the cord will be immediately cut even when used as a cord used in a mower. On the other hand, it is preferably 300,000 or less, and more preferably 250,000 or less. This is because if it exceeds 300,000, the molecular weight may be too high to be processed into a cord. At the same time, a polymer that does not satisfy the above tensile modulus value may be crosslinked to satisfy the above tensile modulus value.

  The biodegradable resin compositions listed up to here may be used alone or as a mixture thereof, among which polybutylene succinate, polybutylene succinate adipate, polybutylene adipate, It is preferable to use at least one resin selected from terephthalate or a mixture thereof because a tensile elastic modulus suitable for the purpose of the present invention can be easily obtained.

  Furthermore, as the biodegradable resin used in the present invention, a lactic acid resin may be mixed with the biodegradable resin composition. The cord used for the cord-type mower according to the present invention has an appropriate length and hardness depending on the type of lawn to be cut. Therefore, the tensile elastic modulus at 23 ° C. based on JIS K7127 is 10 MPa or more and 1000 MPa or less. In such a range, by mixing a lactic acid resin having a high elastic modulus, a cord having a higher elastic modulus corresponding to the type of grass can be obtained than when the above biodegradable resin composition is used alone. Can do.

  In this case, the blending amount of the lactic acid resin is such that the ratio of the lactic acid resin in the entire biodegradable resin including the biodegradable resin composition and the lactic acid resin is 1% by mass or more. Preferably, it is preferably 5% by mass or more, more preferably 10% by mass or more. When less than this range, the effect of improving the elastic modulus by blending the lactic acid resin cannot be obtained sufficiently. On the other hand, it is preferably 40% by mass or less, more preferably 30% by mass or less, and further preferably 20% by mass or less. If it exceeds this range, the elastic modulus will be greatly improved, so the danger at the time of use and at the time of breakage may be remarkably increased.

  Here, the lactic acid-based resin means poly (L-lactic acid) whose structural unit is L-lactic acid, poly (D-lactic acid) whose structural unit is D-lactic acid, structural units that are L-lactic acid and D-lactic acid. These may be poly (DL-lactic acid) or a mixture thereof, and may be a copolymer of these with α-hydroxycarboxylic acid or diol / dicarboxylic acid. At this time, an arbitrary ratio can be used for the ratio of D-lactic acid and L-lactic acid in the lactic acid-based resin. Representative examples of the lactic acid-based resin include “Lacia” series manufactured by Mitsui Chemicals, Inc., “Nature Works” series manufactured by Nature Works, and the like.

  As a polymerization method for these lactic acid-based resins, any known method such as a condensation polymerization method or a ring-opening polymerization method can be employed. For example, in the condensation polymerization method, L-lactic acid, D-lactic acid, or a mixture thereof can be directly subjected to dehydration condensation polymerization to obtain a lactic acid resin having an arbitrary composition.

  In the ring-opening polymerization method, a polylactic acid-based polymer can be obtained using a selected catalyst while using lactide, which is a cyclic dimer of lactic acid, with a polymerization regulator or the like as necessary. Lactide includes L-lactide, which is a dimer of L-lactic acid, D-lactide, which is a dimer of D-lactic acid, and DL-lactide composed of L-lactic acid and D-lactic acid. A lactic acid resin having an arbitrary composition and crystallinity can be obtained by mixing and polymerizing.

  Furthermore, if necessary, such as improving heat resistance, a non-aliphatic diol such as a non-aliphatic dicarboxylic acid such as terephthalic acid and / or an ethylene oxide adduct of bisphenol A may be used as a small amount copolymerization component. Good. Furthermore, for the purpose of increasing the molecular weight, a small amount of a chain extender such as a diisocyanate compound, an epoxy compound, and an acid anhydride can be used.

  The other hydroxy-carboxylic acid unit copolymerized with the lactic acid resin is an optical isomer of lactic acid (D-lactic acid for L-lactic acid, L-lactic acid for D-lactic acid). , Glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyn-butyric acid, 2-hydroxy3,3-dimethylbutyric acid, 2-hydroxy3-methylbutyric acid, 2-hydroxycaproic acid, etc. Examples include lactones such as hydroxy-carboxylic acid, caprolactone, butyrolactone, and valerolactone.

  Examples of the aliphatic diol copolymerized with the lactic acid resin include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid.

  Furthermore, a preferable range of the weight average molecular weight of the lactic acid resin is 50,000 to 400,000, more preferably 100,000 to 250,000. When it is below this range, practical properties are hardly expressed, and when it exceeds, the melt viscosity is too high and the molding processability is poor.

  Furthermore, the said biodegradable resin used by this invention may mix | blend the filler which consists of a granular filler, a plate-shaped filler, or both. By blending these fillers, the tensile elastic modulus can be adjusted as appropriate, and the desired cutting force can be adjusted.

  Here, the difference between the above-mentioned granular filler and plate-like filler is based on the standards described on pages 10 to 16 and 23 to 30 of the “Filler Utilization Dictionary” edited by the Filler Research Society, Those having an aspect ratio of 2 to 30 are referred to as plate-like fillers, and those having an aspect ratio of 2 or less or those having no aspect ratio are referred to as granular fillers.

  Specific examples of such plate filler include talc, mica, sericite, glass flake, synthetic mica, montmorillonite, graphite, metal foil, plate calcium carbonate, plate alumina and the like. Specific examples of the particulate filler include organic beads such as calcium carbonate, silica, acrylic beads, various balloons, alumina, titanium oxide, gray, metal powder, hydrotalcite, magnesium hydroxide, zinc oxide, calcium silicate. , Aluminum hydroxide, carbon black, barium titanate, various ferrites and the like. Among these, in view of cost and impact strength, it is preferable to use talc as the plate-like filler and calcium carbonate as the granular filler.

  Moreover, the dispersibility of the filler by treating the surface of the plate-like filler and the granular filler with a silane coupling agent such as higher fatty acid, titanic acid, methacrylic silane, vinyl silane, epoxy silane, amino silane, and You may improve adhesiveness with resin.

  The particle size of the plate-like filler is preferably 1.5 μm or more, and more preferably 2.0 μm or more. On the other hand, it is preferably 10.0 μm or less, and more preferably 6.0 μm or less. In addition, the particle size of the granular filler is preferably 0.1 μm or more, and more preferably 0.5 μm or more. On the other hand, it is preferably 1.5 μm or less, and more preferably 1.3 μm or less. Below this range, the strength of the cord used in the mower will be reduced due to the aggregation of the filler, and when above this range, the filler will be the starting point of breakage and the mechanical properties of the cord used in the mower will be significantly reduced. Produce. In addition, the value of the range of the average particle diameter shown here is the value measured by the laser diffraction method.

  As a compounding quantity of these fillers, it is preferable to mix | blend in the ratio of 1 mass part or more with respect to 100 mass parts of said biodegradable resin compositions, and it is more preferable to mix | blend in the ratio of 5 mass parts or more. If it falls below this range, the effect of improving the elastic modulus may not be obtained. On the other hand, it is preferable to mix | blend in the ratio of 20 mass parts or less, and it is more preferable to mix | blend in the ratio of 15 mass% or less. When exceeding this range, although the elastic modulus of the cord used for the mower is improved, it becomes extremely brittle, which may cause a practical problem.

  In addition, the biodegradable resin used in the present invention is a heat stabilizer, an antioxidant, and the like, as long as the effects of the present invention are not impaired, in addition to the biodegradable resin composition, the lactic acid resin, and the filler. Additives such as UV absorbers, light stabilizers, pigments, dyes, colorants, lubricants, nucleating agents, and plasticizers can be formulated.

  When such a cord using the biodegradable resin is used as a cord for a cord type mower, it exhibits an effective cutting force not only for general turf but also for some special turf. In addition, even if it hits the human body during work, the possibility of serious injury is sufficiently suppressed.

  Specifically, the method for producing a cord used in the cord-type mower according to the present invention sufficiently dries the biodegradable resin composition and, if necessary, the other lactic acid-based resin, filler, additive, and the like. After removing water, melt and mix using a single-screw extruder or twin-screw extruder, extrude into a strand shape, and cool sufficiently in air, cold water, warm water, or a cooling cast. The cord used for the mower is produced by winding up the strand-shaped resin with a winder. At this time, it is preferable to appropriately select the melt extrusion temperature in consideration of the change in the melt viscosity of the mixed resin depending on the type of the biodegradable resin and the amount of other additives.

  For example, in the case of polybutylene succinate adipate, 160 ° C to 230 ° C is selected as the preferred temperature range. Further, when extruded into a strand shape, 0.1 times or more and 6.0 times or less, more preferably 0.5 times or more and 3.0 times or less, and further preferably 1.0 times or more, 2.5 times or more. The elastic modulus of the cord used in the mower of the present invention can be arbitrarily adjusted by stretching at a magnification of twice or less. The stretching temperature at this time is preferably selected as appropriate because the elastic modulus changes depending on the type of biodegradable resin, the amount of other additives, the stretching ratio, and the like. For example, in the case of polybutylene succinate adipate, a range of 80 ° C. to 120 ° C. is selected as a preferred temperature range.

  The diameter of the cord used for the cord type mower thus obtained is preferably 1 mm or more. On the other hand, it is preferably 5 mm or less, and more preferably 3 mm or less. However, the cross section of the cord is not limited to a circular shape, and may be a square shape or a star shape. The number of rotations of the cord is appropriately selected depending on the application, but a range of 9000 rotations / minute to 13000 rotations / minute can be normally selected.

  Hereinafter, the present invention will be described more specifically with reference to examples. First, the measurement method used in the examples will be described.

<Tensile modulus measurement method>
Based on JIS K7127, using a strip-shaped test piece having a length of 300 mm, a width of 5 mm, and a thickness of 0.2 mm, Toyo Seiki Seisakusho Co., Ltd .: Tensilon II type universal testing machine with a temperature of 23 ° C. and a relative humidity of 50% The tensile modulus was measured below.

<Mowing performance measuring method>
Makita Mower: When a cord used for a mower with a diameter of 2mmφ and a length of 300mm is attached to a MUM252, and when weeds a land with a width of 50mm and a length of 2000mm overgrown about 5cm, it makes two round trips in the longitudinal direction. Evaluation was made based on the area ratio where weeds were cut to 1 cm or less. A case where the area ratio cut to 1 cm or less was 70% or more of the whole was regarded as acceptable.

<Biodegradability measurement method>
As an evaluation of biodegradability, a simple compost test was conducted. 5 kg of commercially available dog food was mixed with 10 kg of humus for horticulture and added to a commercially available household conposter, and 500 ml of water was further added to form 200 mm thick buried soil. A cord-like sample having a diameter of 2 mm and a length of 10 cm was sandwiched between sample holders composed of two 60 mm × 150 mm wire nets (third mm) in order to minimize contact with the outside and collapse and scattering. Above, a thin wire was passed through the mesh to bind the sample. The sample was embedded together with the sample holder so as to be vertical in the composter soil. The lower base of the sample holder was placed at a height of 25 mm from the surface of the buried soil, and the upper base was placed at a height of 25 mm from the bottom of the buried soil. The temperature of the composter was constant at 60 ° C. One week later, a sample was taken out and the state was observed to confirm the presence or absence of collapse. The state of the sample was evaluated as follows, and a sample that completely collapsed was regarded as acceptable.
○: Completely collapsed X: Cracks occurred in the sample but the shape was retained or the original shape was retained

(Example 1)
Showa High Polymer Co., Ltd. product: Bionore 1003 (polybutylene succinate) was used as a biodegradable resin, kneaded at 200 ° C. with a 40 mmφ co-directional twin screw extruder, and then extruded from a strand die. Subsequently, it was cooled in a constant temperature water bath at 20 ° C., and a cord used for a 2 mmφ × 1000 mm mower was wound up by a winder. The number of revolutions of the cord was 10,000 revolutions / minute. Using the obtained cord, the mowing performance and biodegradability were evaluated. Subsequently, the obtained cord was pressed into a sheet having a thickness of 0.2 mm at 200 ° C. and 10.5 MPa using a vacuum press (Molding press VH1-1747 manufactured by Kitagawa Seiki) to a width of 5 mm and a length of 300 mm. Cutting out and measuring the tensile modulus. The obtained results are shown in Table 1.

(Example 2)
Mowing performance according to the same procedure as in Example 1 except that GS Pla AZ91T (1,4-butanediol, succinic acid, lactic acid copolymer) manufactured by Mitsubishi Chemical Corporation was used as the biodegradable resin. And the code | cord | chord used for a mower for evaluation of biodegradability, and the sheet | seat were produced for evaluation of a tensile elasticity modulus. Table 1 shows the results of evaluating the tensile modulus, mowing performance, and biodegradability of the obtained sample.

(Example 3)
Except for using BASF Ecoflex F (polybutylene adipate terephthalate) as a biodegradable resin, using the same procedure as in Example 1 for evaluating mowing performance and biodegradability in a mower. A sheet was prepared for evaluation of the cord and tensile modulus. Table 1 shows the results of evaluating the tensile modulus, mowing performance, and biodegradability of the obtained sample.

Example 4
Using Nature Works 4032D (polylactic acid) manufactured by Nature Works as a lactic acid-based resin, and using GS Pla AZ91T (copolymer of 1,4-butanediol, succinic acid, and lactic acid) as the biodegradable resin composition. The biodegradable resin obtained by dry blending these biodegradable resin compositions and lactic acid resins at a mass ratio of 90:10 and then kneading at 200 ° C. in a 40 mmφ co-directional twin screw extruder In the same manner as in Example 1, a cord used for a mowing machine for evaluation of mowing performance and biodegradability, and a sheet for evaluation of tensile elastic modulus were prepared. Table 1 shows the results of evaluating the tensile modulus, mowing performance, and biodegradability of the obtained sample.

(Example 5)
GS Pla AZ91T was used as the biodegradable resin composition, Nature Works 4032D was used as the lactic acid resin, and these were dry blended at a mass ratio of 70:30 and kneaded in the same manner as in Example 4. About the degradable resin, the sheet | seat was produced by the method similar to Example 1 for the mowing performance and biodegradability evaluation of the cord used for a mowing machine, and evaluation of a tensile elasticity modulus. Table 1 shows the results of evaluating the tensile modulus, mowing performance, and biodegradability of the obtained sample.

(Example 6)
GS Pla AZ91T was used as the biodegradable resin composition, Ecoflex F was used as the lactic acid resin, and these were dry blended at a mass ratio of 80:20 and kneaded in the same manner as in Example 4. About the degradable resin, the sheet | seat was produced by the method similar to Example 1 for the mowing performance and biodegradability evaluation of the cord used for a mowing machine, and evaluation of a tensile elasticity modulus. Table 1 shows the results of evaluating the tensile modulus, mowing performance, and biodegradability of the obtained sample.

(Example 7)
As a plate-like filler, Nihon Talc Co., Ltd. product: Microace L1 (talc, average particle size: 4.9 μm) is used, and GS Pla AZ91T is used as a biodegradable resin. The dry blending was performed at a ratio of 20, and cords used for mowing performance and biodegradability were evaluated in the same manner as in Example 1, and sheets were prepared for evaluation of tensile modulus. Table 1 shows the results of evaluating the tensile modulus, mowing performance, and biodegradability of the obtained sample.

(Comparative Example 1)
For evaluation of mowing performance and biodegradability in the same manner as in Example 1 except that Unitika Ltd .: A1030BRT (polyamide 6) was used instead of the biodegradable resin and the kneading temperature was 260 ° C. Sheets were prepared for evaluation of cords used in mowers and tensile elastic modulus. Table 1 shows the results of evaluating the tensile modulus, mowing performance, and biodegradability of the obtained sample.

(Comparative Example 2)
Using only Nature Works 4032D, which is polylactic acid, not included in the biodegradable resin according to the present invention, it is used in a mower for evaluation of mowing performance and biodegradability in the same manner as in Example 1. Sheets were prepared for evaluation of cords and tensile modulus. Table 1 shows the results of evaluating the tensile modulus, mowing performance, and biodegradability of the obtained sample.

(Comparative Example 3)
GS Pla AZ91T was used as a biodegradable resin composition, and Nature Works 4032D was dry blended at a mass ratio of 30:70 as a lactic acid-based resin, and then grass cutting performance and biodegradability were obtained in the same manner as in Example 1. A cord used for a mower was used for evaluation and a sheet was prepared for evaluation of tensile modulus. Table 1 shows the results of evaluating the tensile modulus, mowing performance, and biodegradability of the obtained sample.

Schematic diagram of cord type mower

Explanation of symbols

11 Turntable 12 Code 13 Handle 14 Handle

Claims (6)

  A cord used for a cord-type mower made of a biodegradable resin having a tensile elastic modulus at 23 ° C. of 10 MPa or more and 1000 MPa or less based on JIS K7127.   The biodegradable resin contains at least one biodegradable resin composition selected from aliphatic polyesters other than polylactic acid, aromatic aliphatic polyesters, and polyesters of diol, dicarboxylic acid, and lactic acid. The cord used for the cord type mower according to claim 1.   The biodegradable resin is at least one kind selected from polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, and polyester of 1,4-butanediol, succinic acid and lactic acid. The cord used for the cord type mower according to claim 2, comprising a decomposable resin composition.   The biodegradable resin is a biodegradable resin composition comprising at least one selected from aliphatic polyesters other than polylactic acid, aromatic aliphatic polyesters, polyesters of diol, dicarboxylic acid and lactic acid resin, and The cord used for the cord type mower according to any one of claims 1 to 3, wherein the cord type mower is blended with a lactic acid resin in a ratio of 1% by mass to 40% by mass with respect to the entire biodegradable resin.   The filler which consists of a granular filler, a plate-shaped filler, or both with respect to 100 mass parts of said biodegradable resin was mix | blended in the ratio of 1 mass part or more and 20 mass parts or less. Cord used for cord type mower.   A cord type mower using the cord used in the cord type mower according to any one of claims 1 to 5.

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