JPH11215925A - Biodegradable tool for fixing runner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biodegradable tool for fixing a runner, capable of easily controlling the rate of biodegradation and having excellent workability and an excellent effect for fixing the runner to the ground. SOLUTION: This biodegradable tool for fixing a runner comprises a bar-like bent member made from a biodegradable composition comprising 100 pts.wt. of an aliphatic polyester resin, 10-150 pts.wt. of a filler and 0.1-5.0 pts.wt. of a mold release agent. Plural holding members 2 are formed on the surfaces of the soil insertion portions 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable runner stopper formed by using a composition containing an aliphatic polyester, a filler and a release agent and having excellent biodegradability and mold release properties. More specifically, it is possible to control the biodegradation rate, and further comprises a biodegradable composition that can be injection molded,
The present invention relates to a biodegradable runner stopper excellent in workability.

[0002]

2. Description of the Related Art Conventionally, in plants where runners such as strawberries, watermelons, pumpkins, and melons propagate on the ground, runner stoppers for fixing the runners to the ground surface have been used. Wire, straw, paper, or the like is used for the runner stopper.

[0003]

A runner stopper made of a material such as a wire needs to be collected after use, and if left as it is, not only will it hinder the next cropping,
The stop of the runner may adversely affect the growth of the plant. On the other hand, runner stoppers made of wheat straw or paper material decompose in the natural world with the passage of time, so there is no need for collection compared to materials such as wire, so workability is improved, and the impact on plants, etc. is improved. You also need less.

[0004] However, runner stoppers made of wheat straw, paper, and the like have poor strength, and thus are liable to lose their shape during installation, and have a problem of becoming hard after water absorption and drying. Therefore, especially in the case of strawberry cultivation, the runner stopper that became hard after water absorption and drying damaged the strawberry runner and caused anthrax. SUMMARY OF THE INVENTION An object of the present invention is to provide a biodegradable runner stopper which overcomes the above-mentioned conventional drawbacks, is easier to control the biodegradation rate than aliphatic polyester, and has excellent workability and soil stopping effect.

[0005]

The biodegradable runner stopper of the present invention is obtained by molding a biodegradable composition obtained by adding a filler and a release agent to an aliphatic polyester resin into a rod-shaped bent body by an injection molding method. Further, a plurality of locking portions are formed on the surface of the soil insertion portion. The rod-shaped bent body forming the biodegradable runner stopper of the present invention is formed by bending a hollow or solid rod-shaped body between both ends, and the inside of the bent portion serves as a locking portion of the runner. .

[0006] Usually, this bent portion is located at the center of the rod-shaped body,
Although it is bent and formed in a V-shape or a U-shape, it may be bent in a U-shape in the vicinity of one end or bent several times to form a W-shape, for example. The locking portion formed on the surface of the soil-inserted portion of the rod-shaped bent body has a function of preventing the biodegradable runner stopper inserted into the soil from coming off, and is usually formed in a projecting shape at regular intervals. . In addition,
It is preferable that the end portion of the rod-shaped bent body has a shape in which the tip is thinned to easily pierce the soil.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a biodegradable runner stopper of the present invention will be described in detail with reference to FIGS. The biodegradable runner stopper of the present invention forms a rod-shaped body made of a hollow or solid biodegradable composition into a rod-shaped bent body as shown in FIGS. FIG. 1A shows a configuration in which a biodegradable runner stopper is bent in a V shape, which is suitable for a runner having a relatively small diameter, and FIG. 1B shows a configuration in which the stop is bent in a U shape. Suitable for those with relatively large runner diameter.

(C) is bent in a U-shape in the vicinity of one end, and since there is only one soil insertion portion, the insertion work becomes easy. (D) is a configuration bent in a W-shape, and this type can fix two adjacent runners simultaneously. In the biodegradable runner stopper shown in FIGS. 1B and 1D, the tip of the soil insertion portion 1 is tapered. The biodegradable runner stopper of the present invention is not limited to the above-described shape, and may have any shape as long as it is a rod-like body having a bent portion serving as a locking portion of the runner.

FIGS. 2 (a) to 2 (c) show locking portions 2 formed on the surface of the soil insertion portion 1 of the biodegradable runner stopper.
Is exemplified. This locking portion 2 may be integrally formed so that this portion becomes thick when the rod-shaped body is formed,
Alternatively, as shown in FIG. 2B, the recess may be formed by partially caulking at several places, and the adjacent portion may be formed as a bulge. By forming the locking portion in this manner, the biodegradable runner stopper becomes difficult to come off from the soil, and the runner can be reliably held for a long period of time. Further, when the rod-shaped body and the locking portion are formed in a hollow shape, the whole surface area can be increased, and a biodegradable runner stopper that is easily biodegradable can be obtained. The cross-sectional shape of the biodegradable runner stopper of the present invention can be selected from various shapes such as a circular shape, an elliptical shape, and a polygonal shape. Of these, a circular shape is preferable for molding. Moreover, you may make it hollow as needed.

[0010] The length of the biodegradable runner stopper of the present invention is:
Usually, 5-20 cm, preferably 8-15 cm,
It is formed into a rod having an outer diameter of 1 to 6 mm. When the biodegradable runner stopper is a hollow rod-shaped body, the outer diameter is usually 1 to 6 mm, the inner diameter is 0.5 to 3 mm, and the thickness is 0.5.
~ 4.0mm, preferably 2 ~ 6mm outer diameter, 1 ~ inner diameter
3 mm and a thickness of 1 to 3 mm. Outside of the above range, it is difficult to handle and is inferior in workability.

FIG. 3 shows an example in which the V-shaped biodegradable runner stopper of the present invention shown in FIG. 2A is used for a strawberry. The V-shaped biodegradable runner stopper is used by bringing the inside of the bent portion of the rod-shaped bent body into contact with a necessary portion of the strawberry runner 3 and inserting the end portion into the soil. This biodegradable runner stopper is easy to insert because the end of the bar-shaped bent body is thin, and after insertion into the soil, it is difficult to come off due to the presence of the locking portion 2.

As the aliphatic polyester resin usable in the present invention, a known polyhydroxyalkanoate resin or polyalkylalkanoate having no aromatic ring in the molecule can be used without any limitation. Examples of the polyhydroxyalkanoate-based resin include a polylactic acid-based resin, a polycaprolactone-based resin, and a copolymer of 3-hydroxybutyrate and 3-hydroxybutyrate. 3-Hydroxybutyrate and 3-hydroxybutyrate copolymers are available, for example, from hydrogen bacteria Alcaligenes e.
resin produced by microorganisms such as utrophus,
Specifically, "trade name: Biopole" (manufactured by Monsanto Japan Limited) is exemplified. The copolymerization ratio of 3-hydroxybutyrate is preferably 5 to 20% from a practical viewpoint. For example, as the polylactic acid-based resin used in the present invention, a lactide obtained by lactic acid fermentation of glucose is converted into lactide by a ring-closing reaction, and then a known method of ring-opening polymerization, or direct dehydration-condensation polymerization of lactic acid It is obtained by doing. Since lactic acid constituting polylactic acid-based resin has asymmetric carbon,
There are three types of optical isomers, L-form, D-form and DL-form, and any of them may be used, or a mixture thereof.

However, the content of the L-form is preferably 85% or more, more preferably 95% or more, from the viewpoint of physical properties, heat resistance and availability. The molecular weight is not particularly limited, but as the molecular weight increases, the strength improves, but conversely, the melt viscosity increases and the moldability decreases. Therefore, the weight average molecular weight is preferably 20,000.
１，1,000,000, more preferably 50,000-500,000 in terms of weight average molecular weight.
When the weight-average molecular weight is less than 20,000, practical properties are hardly exhibited, which causes a problem.

When the weight average molecular weight exceeds 1,000,000, the melt viscosity becomes too high and molding becomes difficult. In addition, an aliphatic polyester obtained by dehydration-condensation of lactic acid, dicarboxylic acid and diglycol and / or a copolymer of polyether polyester obtained by dehydration-condensation of dicarboxylic acid and polyether polyol are also added as long as the effects of the present invention are not impaired. It does not matter.

As the polyalkylalkanoate resin containing a diglycol component and an aliphatic dicarboxylic acid component or a derivative component thereof as constituent units, any resin can be used as long as it does not contain an aromatic ring in the structural unit. is there.
Examples of the diglycol that is a constituent component of the polyalkylalkanoate resin include ethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, 1,6-hexanediol, decamethylene glycol, neopentyl glycol, and cyclohexaene. Methylene glycol and the like can be mentioned, and they are appropriately selected from these, and at least one kind is used.

The aliphatic dicarboxylic acid component which is a constituent component of the polyalkylalkanoate resin includes, for example, succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, derivatives thereof, and anhydrides thereof. Can be selected from these, and at least one
Types. Oxycarboxylic acids such as malic acid, tartaric acid, and crenic acid may be added as needed. One or more resins selected from these and condensation-polymerized may be used as necessary. The higher the molecular weight, the higher the strength, but the lower the moldability, conversely, the number average molecular weight is preferably in the range of 5,000 to 300,000.

When the molecular weight of the polyalkyl alkanoate resin is represented by the melt fluidity, the temperature is 190 ° C. and the load is 2.16.
The melt flowability in kgf is preferably 0.5 to 50.
g / 10 minutes, more preferably 3.0 to 30 g / 1.
The range is 0 minutes. If the melt fluidity is less than 0.5 g / 10 minutes, the melt viscosity will be extremely high and molding will be difficult. When the melt fluidity exceeds 50 g / 10 minutes, the obtained biodegradable runner stopper is broken when it is bent with a finger, and practical properties are hardly exhibited, which causes a problem.

As the polycaprolactone resin, a resin obtained by ring-opening polymerization of ε-caprolactone at room temperature using active hydrogen such as alcohol as an initiator can be used. The functional number of the initiator is not particularly limited, and bifunctional or trifunctional ones can be preferably used. When the molecular weight is represented by melt fluidity, the melt fluidity at a temperature of 190 ° C. and a load of 2.16 kgf is preferably in the range of 0.5 to 50 g / 10 min, more preferably in the range of 3.0 to 30 g / 10 min. is there.

When the melt fluidity is less than 0.5 g / 10 minutes, the melt viscosity becomes extremely high and molding becomes difficult. If the melt fluidity exceeds 50 g / 10 minutes, the resulting biodegradable runner stopper loses toughness and poses a problem because practical properties are hardly exhibited. These aliphatic polyester resins may be used alone or in combination of two or more.

In the present invention, by adding a filler, the biodegradability of the biodegradable runner stopper can be improved, the molding cycle can be shortened, and the production cost can be reduced. As the inorganic filler used in the present invention, conventionally known inorganic fillers can be used without any limitation. For example, magnesium, calcium,
One type of metal oxide, hydroxide, carbonate, sulfate, silicate, or the like selected from metals such as barium, boron, aluminum, silicon, titanium, zirconium, and hafnium can be given. These metal oxides, hydroxides, carbonates or sulfates are used without particular limitation.

Specific examples of particularly preferred inorganic fillers include oxides such as magnesium oxide, calcium oxide, boron oxide, aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium carbonate, and the like.
Carbonates such as calcium carbonate and barium carbonate; hydroxides such as magnesium hydroxide, calcium hydroxide and aluminum hydroxide; sulfates such as calcium sulfate, barium sulfate and aluminum sulfate; hydrous magnesium silicate (talc); Silicates such as aluminum silicate (clay); Preferred are titanium oxide, silicon oxide, hydrous magnesium silicate, hydrous aluminum silicate and the like. Since these fillers have the effect of promoting crystallization of the resin, the molding cycle can be increased.
Organic fillers include wheat, corn, cereals such as rice, potatoes, sweet potatoes, starches of potatoes such as tapioca, cellulose,
And polysaccharides such as chitin and chitosan. These may be used alone or in combination of two or more.

The above-mentioned fillers such as silane coupling agents, titanate coupling agents, aluminate coupling agents, acetylene glycol or acetylene alcohol are used for the purpose of improving the aggregation of particles and the affinity with the aliphatic polyester. Using a surface modifier, dry method,
The surface may be modified by a wet method or an integral blend method. The average particle size of the filler used in the present invention is in the range of 0.01 to 10 μm, preferably 0.1 to 10 μm.
05 to 5 μm. If it is less than 0.01 μm, the dispersion of the filler in the aliphatic polyester resin is poor, and
If it exceeds 300, the toughness of the biodegradable runner stopper may decrease.

The amount of the filler is 10 to 150 parts by weight, preferably 30 to 100 parts by weight, based on 100 parts by weight of the aliphatic polyester resin. When the amount is less than 10 parts by weight, the effect of improving the biodegradability is hardly recognized, and it is difficult to reduce the production cost of the biodegradable runner stopper. If the amount exceeds 150 parts by weight, the toughness of the biodegradable runner stopper decreases, and the properties required for the runner stopper are lost. In addition, the melt viscosity increases and molding of the runner stopper becomes difficult.

On the other hand, examples of the release agent include aliphatic carboxylic acids having 10 to 21 carbon atoms, such as behenic acid and stearic acid, pentaerythritol-adipate-stearate complex ester, dipentaerythritol-adipate-stearate. An aliphatic ester of a complex ester, an alkyl-modified silicone, a methylstyryl-modified silicone, a polyether-modified silicone, a higher fatty acid alkoxy-modified silicone, a higher fatty acid-containing silicone, a higher fatty acid ester having a viscosity at 25 ° C. in the range of 10 to 10,000 cs. Modified silicone such as modified silicone, methacryl-modified silicone, fluorine-modified silicone, paraffin,
And aliphatic amides. The amount of the release agent is 0.1 to 100 parts by weight of the aliphatic polyester resin.
It is 5.0 parts by weight, preferably 0.5 to 3 parts by weight. When the amount is less than 0.1 part by weight, a sufficient releasing effect cannot be obtained. When the amount exceeds 5.0 parts by weight, a bleeding phenomenon in which the additive floats occurs, which adversely affects the appearance and mechanical properties. .

The biodegradable composition of the present invention may contain, if necessary, a surfactant such as glycerin fatty acid ester, polyglycerin aliphatic ester, di-2-ethylhexyl azelate, phosphorus-based, phenyl-based or lactic acid inorganic salt. Stabilizers, pigments and other additives can be added. The biodegradable composition of the present invention has a temperature of 190 ° C. and a load of 2.16.
The melt flowability in kgf is 0.5 / 10 min to 50 g /
10 minutes, preferably 3 g / 10 minutes to 30 g / 10
Minutes. If the melt fluidity is less than 0.5 g / 10 minutes, the melt viscosity will be extremely high and molding will be difficult. When the melt fluidity exceeds 50 g / 10 minutes, the toughness of the biodegradable runner stopper decreases, and the properties required for the runner stopper are lost.

[0026]

[Example 1] 100 parts by weight of a polylactic acid-based resin (trade name: NIRACTI 9000, manufactured by Shimadzu Corporation) as an aliphatic polyester-based resin, 50 parts by weight of magnesium carbonate as a filler, and mold release Using a biodegradable composition containing 0.5 parts by weight of behenic acid as an agent and 0.5 parts by weight of a methylstyryl-modified silicone (trade name: KF-410, manufactured by Shin-Etsu Chemical Co., Ltd.), injection molding was carried out as shown in FIG. A biodegradable runner stopper for strawberries shown in (b) was prepared. When this biodegradable runner stopper was used to stop the runner of a strawberry planted in 1 are, there was no need for bending work like the conventional runner stopper, and it was easy to insert into the soil, so there was no hand fatigue and work efficiency. Has improved significantly. Also, there was no lifting from the soil due to the growth of the runner as in the case of the conventional stop of the runner. Furthermore, 60 days after using these biodegradable runner stoppers for stopping the runners of strawberries, biodegradation had progressed and the soil part had disappeared spontaneously.

[0027]

According to the biodegradable runner stopper of the present invention, the type and amount of the filler to be mixed with the aliphatic polyester are appropriately selected, and the biodegradation rate in consideration of the life of a plant using the biodegradable runner stopper. By doing so, collection after use is unnecessary, the workability is excellent, and the material has a shape that does not easily fall out of the soil.

[Brief description of the drawings]

FIGS. 1A to 1D are views showing an example of a biodegradable runner stopper of the present invention.

FIGS. 2A to 2C are diagrams showing another example of the biodegradable runner stopper of the present invention.

FIG. 3 is a perspective view of the use state of the biodegradable runner stopper of the present invention.

[Explanation of symbols]

 1 Soil insertion part 2 Lock part 3 Strawberry runner

Claims (2)

[Claims] 1 to 150 parts by weight of a filler and 0.1 to 0.1 parts by weight of a release agent based on 100 parts by weight of an aliphatic polyester resin.
A biodegradable runner stopper comprising a rod-shaped bent body made of a biodegradable composition containing 5.0 parts by weight. 2. The biodegradable runner stopper according to claim 1, wherein the bar-shaped bent body has a plurality of locking portions on the surface of the soil insertion portion.