JP3461648B2 - Biodegradable seedling root cover - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a seedling raising root cover used in the fields of agriculture and horticulture. More specifically, the present invention relates to a biodegradable root cover for transplanting that does not require removal of the seedling-growing container during transplantation, unlike the conventional seed-covering root cover.

[0002]

2. Description of the Related Art In recent years, with an increasing tendency to return to nature,
Cultivation of green trees for planting in parks, gardens, residential areas, etc. is active. Generally, vegetative trees are grown in plantations to a certain size and then dug up and shipped. However, in such a case, there are two serious problems.
That is, the first problem is that, in order to dig up the vegetation tree and ship it, it is necessary to perform a root-wrapping work for protecting the root hair portion, and the work is complicated and the labor cost is high. The second problem is that when excavated, quite thick roots are cut off, and roots often do not root during transplantation and die. For this reason, transplantation was limited to the early spring when metabolic growth of plants was active.

As a means to solve these problems, first, after digging a hole for planting, a cylindrical container made of woven or knitted fabric or non-woven fabric is placed in the hole, and a sapling is planted in the container to grow for a certain period of time. Later, methods have been developed to dig along the perimeter of the container. By this method, since this container functions as a root cover at the time of shipping, the work of root winding at the time of shipping is not required, which leads to a great simplification of workability, and a thick root can be cut when digging up. Since it does not exist, it is expected that the survival rate will improve and shipping will be possible throughout the year.

As a material for such a root cover, it is necessary to maintain stable mechanical strength for at least 1 to 2 years during the seedling raising period even in the presence of microorganisms in the soil or in a humid environment. Therefore, at present, synthetic fibers partially or wholly made of polyester, nylon, polypropylene or the like are used as a material for the root cover. However, since these synthetic fibers such as polyester are not decomposed in the soil, the root cover in which the roots are entangled must be peeled off when excavating and transplanting / implanting, and its disposal is also a problem. On the other hand, for example, when natural or regenerated fibers such as palm and rayon are used as a material for the root cover, they are decomposed too early by microorganisms in the soil, and thus, they can serve as the original root cover. However, the mechanical strength and dimensional stability in a wet environment are lacking, which causes a problem.

[0005]

The present invention has excellent mechanical strength and has a controlled decomposition performance such that it is hardly decomposed during the seedling raising period and is almost completely decomposed after transplanting. The present invention provides a root cover for biodegradable seedlings, which allows the transplant to be carried out as it is while maintaining the mechanical strength required for replanting and without the need to remove the root cover.

[0006]

In order to solve the above problems, the present invention provides a root cover for raising seedlings for covering a root part of a plant and soil around the root, which is biodegradable. Having a fineness of 1 to 1 made of a thermoplastic aliphatic polyester having
50 to 30 basis weight composed of 5 denier long fibers
Formed from a non-woven fabric of 0 g / m ² and having a basis weight of 10
Tensile strength when converted to 0 g / m ² is 5 kg / 5 cm
Width or more, air permeability of 30 cc / cm ² / sec or more, and the thermoplastic aliphatic polyester is selected from the group consisting of polybutylene succinate, polyethylene succinate, polybutylene adipate, and polybutylene sebacate. The gist is that it is a polymer, a copolymer having these polymers as main repeating units, or a blend thereof. Further, the present invention is a root cover for raising seedlings for covering a root part of a plant and soil around the root, which has a fineness of 1 to 15 denier composed of a biodegradable thermoplastic aliphatic polyester. basis weight comprised fibers is formed by a nonwoven fabric of 50 to 300 g / m ^2, and is the tensile strength is 5 kg / 5 cm width or more when converted to the basis weight 100 g / m ^2, air permeability 30cc
/ Cm ² / sec or more, the thermoplastic aliphatic polyester is poly (D-lactic acid), poly (L-lactic acid), D
-A polymer selected from the group consisting of a copolymer of lactic acid and L-lactic acid, a copolymer of D-lactic acid and a hydroxycarboxylic acid, and a copolymer of L-lactic acid and a hydroxycarboxylic acid, or a polymer thereof. It is a blend, and the gist is that a crystal nucleating agent is added to the thermoplastic aliphatic polyester. Furthermore, the present invention is a root cover for raising seedlings for covering a root part of a plant and soil around the root, and having a fineness of 1 made of a thermoplastic aliphatic polyester having biodegradability.
〜50 denier is composed of long fibers 50〜
It is made of a non-woven fabric of 300 g / m ² and has a tensile strength of 5 kg / 5 when converted to a basis weight of 100 g / m ^2.
cm width or more, air permeability of 30 cc / cm ² / sec or more, the thermoplastic aliphatic polyester is a polymer of any one of polycaprolactone and polypropiolactone, or a main repeating unit of these polymers. It is a copolymer, and the gist is that a crystal nucleating agent is added to the thermoplastic aliphatic polyester.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The long fibers applied to the present invention are mainly composed of biodegradable thermoplastic aliphatic polyester.

Examples of biodegradable thermoplastic aliphatic polyesters include poly (α-hydroxy acids) such as polyglycolic acid and polylactic acid, and copolymers containing these as the main repeating unit elements. Also,
Poly (ω-hydroxyalkanoate) such as poly (ε-caprolactone), poly (β-propiolactone)
In addition, poly-3-hydroxypropionate, poly-3-hydroxybutyrate, poly-3-hydroxycaprolate, poly-3-hydroxyheptanoate,
Poly (β, such as poly-3-hydroxyoctanoate
-Hydroxyalkanoate) and copolymers of the repeating unit elements constituting these and the repeating unit elements constituting poly-3-hydroxyvalerate or poly-4-hydroxybutyrate. As the polyalkylene dicarboxylate consisting of a condensation polymer of glycol and dicarboxylic acid, for example, polyethylene oxalate, polyethylene succinate, polyethylene adipate, polyethylene azelate, polybutylene oxalate, polybutylene succinate, polybutylene adipate, Examples thereof include polybutylene sebacate, polyhexamethylene sebacate, polyneopentyl oxalate, and polyalkylene dicarboxylate copolymers having repeating unit elements constituting these.

Further, it is also possible to select a plurality of polymers each having such a biodegradability individually and blend them to be applied. In the present invention, from the viewpoint of biodegradability and spinnability, among the above, in particular, any one of polylactic acid-based polymer, polybutylene succinate, polyethylene succinate, polybutylene adipate, and polybutylene sebacate is used. A polymer or a copolymer having these polymers as main repeating units, a polymer of any one of polycaprolactone and polypropiolactone, a copolymer having these polymers as main repeating units, or a blend thereof. Is preferred.

When the thermoplastic aliphatic polyester is a polylactic acid type polymer, specifically, poly (D-lactic acid),
Among poly (L-lactic acid), a copolymer of D-lactic acid and L-lactic acid, a copolymer of D-lactic acid and hydroxycarboxylic acid, or a copolymer of L-lactic acid and hydroxycarboxylic acid A polymer having a melting point of 80 ° C. or higher is preferable. Here, as the hydroxycarboxylic acid in the case of a copolymer of lactic acid and hydroxycarboxylic acid, glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid, hydroxyheptanoic acid, hydroxyoctanoic acid, etc. Can be mentioned.

When the thermoplastic aliphatic polyester is polyalkylene dicarboxylate, any polymer selected from polybutylene succinate, polyethylene succinate, polybutylene adipate, polybutylene sebacate, or these polymers is used. A copolymer having a main repeating unit is preferable, and specifically, a copolymer composed of 70 mol% or more of butylene succinate and ethylene succinate, butylene adipate, or butylene sebacate is preferable.

The thermoplastic aliphatic polyester is poly (ω
In the case of (hydroxyalkanoate), a polymer of either polycaprolactone or polypropiolactone, or a copolymer containing these polymers as main repeating units is preferable.

Further, in the present invention, the above thermoplastic aliphatic polyester, polycapramide (nylon 6), polytetramethylene adipamide (nylon 4) are used.
6), polyhexamethylene adipamide (nylon 6
6), the constituent fibers of the non-woven fabric can also be formed by an aliphatic polyesteramide-based copolymer which is a condensation polymer with an aliphatic polyamide such as polyundecanamide (nylon 11) and polylauramide (nylon 12). .

The thermoplastic aliphatic polyester used in the present invention has a number average molecular weight of about 20,000 or more, preferably 40,000 or more, more preferably 60,000 or more. In terms of Further, it may be chain-extended with a small amount of diisocyanate or tetracarboxylic dianhydride in order to increase the degree of polymerization.

If necessary, various additives such as a matting agent, a pigment and a crystal nucleating agent may be added to the thermoplastic aliphatic polyester applied in the present invention within a range that does not impair the effects of the present invention. May be added in.

In particular, the addition of a crystal nucleating agent such as talc, boron nitride, calcium carbonate, magnesium carbonate and titanium oxide promotes crystallization during thermoforming and improves the heat resistance and mechanical strength of the molded product. At the same time, it is preferable in that fusion (blocking) between yarns in the spinning / cooling step can be prevented. However, if the crystallization of the yarn is promoted too much, the formability is impaired, so the addition amount is 0.1-0.1%.
It is important to use 3.0% by weight, preferably 0.5 to 2.0% by weight.

Furthermore, addition of a black pigment or dye such as carbon black or black dye is suitable as a root cover for raising seedlings. That is, when it is buried in the ground, the pigment or dye facilitates the absorption of geothermal heat, improves the heat retention of the roots of plants, and contributes to the growth of roots. However, if the amount of addition is too large, the spinnability is lowered when the fiber is spun, so it is preferable to add it in an amount that does not impair spinnability. Addition amount is 0.1
It is important to use in the range of ~ 3.0 wt%, preferably 0.5-2.0 wt%.

The fiber morphology of the constituent fiber of the present invention may be one using an aliphatic polyester alone or a composite fiber using two or more kinds of aliphatic polyester. Also,
The cross section of the fiber is, in addition to an ordinary round cross section, a hollow cross section, a modified cross section, a parallel composite cross section, a multi-layer composite cross section, a core-sheath composite cross section, a split composite cross section, and any other fiber depending on the purpose and application. A cross-sectional form may be employed. From the viewpoint of decomposition performance, a hollow cross section, a modified cross section, a split type composite cross section and the like are particularly preferable.

In the present invention, the decomposition rate can be controlled by appropriately selecting the type of the aliphatic polyester, the copolymerization ratio of the aliphatic polyester, the blending ratio of the aliphatic polyester, the fiber cross section and the like. Thus, a root cover for raising seedlings having a decomposition rate according to the purpose of use can be obtained.

The method for producing the root cover for raising seedlings of the present invention will be described. First, the long-fiber non-woven fabric for forming the root cover of the present invention can be efficiently manufactured by the so-called spunbond method. That is, the above-mentioned thermoplastic aliphatic polyester is melted by heating and discharged from the spinneret,
After the obtained spun yarn is cooled by using a conventionally known cooling device such as horizontal spraying or annular spraying, the spun yarn is towed and thinned by a suction device such as an air sucker, and subsequently the yarn discharged from the suction device. After the group is opened, the web is opened and accumulated on a moving and accumulating device such as a conveyor including a screen. Then, the web formed on the moving deposition apparatus is partially subjected to thermocompression bonding by using a heated partial embossing roll or a partial thermocompression bonding apparatus such as an ultrasonic fusion bonding apparatus to obtain a long-fiber nonwoven fabric.

Next, as a method for producing a root cover for raising seedlings for covering the root portion of a plant and the soil around the root using the obtained long fiber non-woven fabric, a heat molding method or sewing or heat bonding is used. The method of molding into a bag is adopted. Specific examples of the heat-molding method include a method in which the nonwoven fabric is thermocompression-bonded with a heating instrument and simultaneously melted, and a method in which the nonwoven fabric is thermocompression-bonded and simultaneously melt-melted, but any method is appropriately selected. be able to. For example, the polymer constituting the nonwoven fabric, in the case of being composed of a plurality of polymers, the glass transition temperature of the polymer with the highest melting point or higher, preheated to a temperature of the melting point or less and press-molded in a mold, then, In order to improve the mechanical strength of the molded product, crystallization is accelerated at a temperature near the crystallization temperature. The use of such a heat molding method is preferable because the advantage of the present invention that it is composed of a thermoplastic polymer can be effectively utilized. On the other hand, as described above, it is also possible to adopt a method of cutting the non-woven fabric and joining the ends by sewing or heat bonding.

As a root cover for raising seedlings, when it is buried in soil, a certain level of water permeability and aeration is provided so that a large difference does not occur in soil moisture, fertilizer nutrients, oxygen, etc. inside and outside the cover. It is required to have sex. Moreover, the thin roots of the seedlings need to be able to penetrate from the inside to the outside of the cover in order to absorb the nutrients in the soil over a wide range, while the thick roots avoid cutting at the time of excavation during transplantation. It is necessary to stay inside the cover. Therefore, the root cover for raising seedlings is required to have appropriate compactness. Further, it is also important to balance with the decomposition rate of the material, and if the decomposition rate is too fast, the mechanical strength of the material is remarkably reduced, and a thick root is pierced during the seedling raising period, which is not preferable. By keeping the thick roots inside the cover during the seedling raising period, it is possible to improve the survival rate without cutting the thick roots when excavating and transplanting. In the present invention, these requirements are satisfied by setting the fineness of the constituent fibers of the non-woven fabric, the basis weight of the non-woven fabric, and the air permeability within the above ranges.

It is important that the single filament fineness of the constituent long fibers of the nonwoven fabric constituting the root cover of the present invention is 1 to 15 denier. When the single yarn fineness is less than 1 denier, not only the operability is impaired in the yarn making process, but also the decomposition rate becomes too fast, which is not the object of the present invention. When the single yarn fineness exceeds 15 denier, not only is the cooling property of the spun yarn reduced in the spinning process, but also the flexibility of the resulting nonwoven fabric is impaired, which impairs workability during processing and molding. For these reasons, the single yarn fineness is preferably 2 to 10
Denier is preferable, and 3 to 7 denier is more preferable.

It is important that the non-woven fabric constituting the root cover of the present invention is composed of long fibers satisfying the above-mentioned single yarn fineness and its basis weight is in the range of 50 to 300 g / m ² . When the basis weight is less than 50 g / m ² , the resulting root cover for raising seedlings is inferior in mechanical strength and poor in practicality. On the contrary, when the basis weight exceeds 300 g / m ² , the biodegradability tends to decrease. That is, if the single yarn fineness is thin, a dense non-woven fabric will be obtained even with the same basis weight, but it is necessary to consider that the mechanical strength of biodegradation will decrease rapidly, and if the mechanical strength of the fiber itself is low. In order to maintain a certain strength as a non-woven fabric, it is necessary to increase the single yarn fineness and the basis weight. In addition, these long-fiber nonwoven fabrics having a basis weight may be obtained in one step, or may be obtained by laminating two or more long-fiber nonwoven fabrics and subjecting them to thermocompression bonding or needle punching.

The root cover for raising seedlings of the present invention has a basis weight of 100
It is necessary that the tensile strength when converted to g / m ² is 5 kg / 5 cm width or more. Tensile strength is 5kg / 5c
If the width is less than m, the root cover for raising seedlings may be destroyed due to its too weak strength when soil is added together with the seedlings, which is not preferable. This tensile strength can be controlled by the type of polymer used, the fineness of the constituent fibers, the basis weight of the non-woven fabric, and the conditions for applying thermocompression bonding.

The root cover for raising seedlings of the present invention is required to have an air permeability of 30 cc / cm ² / sec or more. If the air permeability is less than 30 cc / cm ² / sec, the air permeability and the water permeability are too low, which not only hinders the growth of seedlings, but also causes root rot and death, which is not preferable. For these reasons, the air permeability is more preferably 5
It is preferably 0 cc / cm ² / sec or more. This air permeability can be controlled by the type of polymer used, the fineness of the constituent fibers, the basis weight of the non-woven fabric, and the conditions for applying thermocompression bonding.

When the root cover for raising seedlings of the present invention is produced in the form of a container by the above-described heat-molding method, in particular, the crystallinity of the long fibers constituting the nonwoven fabric is 10 to 40% and the supercooling index is 0. It is preferably 4 or less. This allows
It is possible to secure fluidity during thermoforming, particularly during complex and acute-angle deformation processing. Where the crystallinity of long fibers (%)
Is measured by the Roland method using a wide-angle X-ray diffraction pattern of powdered long fibers (nonwoven fabric). That is, in the wide-angle X-ray diffraction method, the interference intensity of diffracted X-rays is measured in the direction of the reflection angle 2θ, and the interference peak based on the crystal is separated from the interference halo based on the crystal from the interference intensity curve obtained there, By quantifying both, the crystallinity (%) can be obtained from the following equation.
Crystallinity of long fiber (%) = (integrated strength of crystal part) / total integrated strength) x 100

On the other hand, the supercooling index of the long fibers can be obtained as follows. That is, first, using a differential scanning calorimeter DCS-2 type manufactured by Perkin Elma Co., Ltd., with a sample weight of 5 mg and a temperature rising rate of 20 ° C./min, a baseline shift start temperature of a melting endothermic curve obtained was measured. An intermediate temperature between the end temperature and the glass transition temperature Tg (° C), and a temperature giving the extreme value of the endothermic peak are defined as the melting point Tm (° C). Then, after maintaining the molten state for 10 minutes, the temperature decrease rate is 20 ° C.
The temperature which gives the extremum of the exothermic curve obtained by cooling as s / min is defined as the crystallization temperature Tc (° C). If two or more extreme values are given, the main peak is adopted. Then, the supercooling index is obtained by the following equation. Supercooling index of long fibers = (Tm-Tc) / (Tm-Tg)

The crystallinity and the supercooling index are indexes relating to formability. When the crystallinity is less than 10%, melting in the high deformation region during thermal deformation easily occurs, and exceeds 40%. Therefore, thermal deformation hardly occurs and deep drawing becomes difficult. On the other hand, when the supercooling index is less than 0.4, the extensibility at the time of thermal deformation is insufficient, and it cannot be efficiently obtained by heat molding.

Further, the fact that the long fibers constituting the nonwoven fabric satisfy the requirements of the above-mentioned crystallinity and supercooling index as in the present invention means, in other words, that the strain stress at the thermoforming temperature of the nonwoven fabric is low and the nonwoven fabric is broken. Since the elongation is high, the effect of preventing breakage of the nonwoven fabric during thermoforming can also be obtained. For example, it is necessary that the elongation at break of the nonwoven fabric at the thermoforming temperature is 50% or more, preferably 80% or more, more preferably 100% or more.

Further, when the long fiber non-woven fabric and the long fibers constituting the root cover of the present invention are molded into a container by a heat molding method, it is preferable that they do not easily shrink during thermoforming. Because if the sheet shrinks during thermoforming,
This is because the sheet is taken in the mold and stable continuous molding becomes difficult. Therefore, the area shrinkage of the nonwoven fabric during thermoforming is 10% or less, preferably 5% or less, and more preferably 2% or less.

The long fiber non-woven fabric constituting the root cover of the present invention is preferably such that the web is partially thermocompressed to maintain the form of the non-woven fabric. This will bond only in the spot fusion zones that are partially formed,
It is possible to impart excellent flexibility to the nonwoven fabric of the present invention,
In particular, during thermoforming, it is possible to secure fluidity during complicated and acute deformation processing, and at the same time, because the partial heat-bonding improves the shape retention of the nonwoven fabric during molding. Here, the partial thermocompression bonding refers to one that forms a point-shaped fusion zone by embossing or ultrasonic fusion treatment, specifically, a heated embossing roll and a smooth metal roll surface. A method of forming spot-shaped fused areas between the long fibers through a web or a method of forming a point-shaped fused area between the long fibers of the pattern part by applying a high frequency by ultrasonic waves on a pattern roll is adopted. It

[0033]

EXAMPLES The present invention will be specifically described below with reference to examples. The present invention is not limited to these examples.

In the examples, each physical property value was determined as follows. -Melting point (° C); Differential scanning calorimeter D manufactured by Perkin Elma
The melting point (° C.) was defined as the temperature at which the exothermic value of the melting endothermic curve obtained by using SC-2 type and measuring the temperature rising rate at 20 ° C./min.

Melt flow rate value (g / 10 minutes);
It was measured according to the method described in ASTM-D-1238 (E) (hereinafter referred to as MFR value).

Intrinsic viscosity of polyethylene terephthalate: Measured at a temperature of 20 ° C. using a mixed solution of phenol and ethane tetrachloride in equal weight as a solvent.

Fineness (denier): The fiber diameter in the state of the web was measured with a 50 microscope and the average value of the fineness obtained by density correction was taken as the fineness (denier).

-Basis weight (g / m ² ); 10 pieces each of 10 cm in length × 10 cm in width were prepared from the sample in the standard state to reach equilibrium water content, and then the weight (g) of each piece was weighed. Then, the average value of the obtained values was converted per unit area to obtain a basis weight (g / m ² ).

Tensile strength (kg / 5 cm width); JIS-
It was measured according to the strip method described in L-1096. That is, 10 pieces each of a sample piece having a sample length of 30 cm and a sample width of 5 cm were prepared, and a constant speed extension type tensile tester (Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd.) was prepared.
The maximum tensile strength (kg / 5 cm width) was obtained by stretching each sample piece at a tensile speed of 10 cm / min, and the average value of the obtained maximum tensile strengths was converted into a basis weight of 100 g / m ^2. Was taken as the tensile strength (kg / 5 cm width).

Tear strength (kg); JIS-L-109
According to the Pendulum method described in 6, the measurement was performed using an Elmendorf type tear tester.

[0041]

[0042]

[0043]

[0044]

Air permeability (cc / cm ² / sec); JIS-
It was measured according to the Frazier method described in L-1096.
That is, a sample with a sample length of 15 cm and a sample width of 15 cm is 3
Using a Frazier type tester, attach the sample to one end of the cylinder, and then adjust the suction pump so that the tilt barometer shows a pressure of 12.7 mm of water column with a variable resistor. The amount of air passing through the sample piece (c
c / cm ² / sec), and the average value was used as the air permeability.

Decomposition performance: A cover used as a sample was dug into the soil by digging a hole, and the decomposition state was visually observed two years and three years after embedding, and the following four grades were evaluated. ⊚: Almost decomposed ○: Significantly decomposed Δ: Less than half decomposed ×: Almost no decomposition

Growth condition of seedlings: A container used as a sample is buried in the soil by digging a hole, and young couscous trees grown in a farm in advance are planted in this container, and after 2 years, outside the container. I dug up along it, carried it to another land as it was, and planted it. Further, one year later, the soil was dug up again to observe the state of root development, and the evaluation was made according to the following three grades.

[0048] ○: Good growth △: normal growth ×; poor growth

Examples 1 to 3 Using polybutylene succinate having a melting point of 115 ° C and a number average molecular weight of 63000, melt spinning from a spinneret under conditions of a spinning temperature of 200 ° C and a single hole discharge rate of 1.16 g / min. did. After the spun yarn is cooled by the cooling device, the pulling speed is 2 with the aspirator provided below the spinneret.
The fiber was drawn and thinned at 600 m / min, opened using a known fiber opener, and collected and deposited as a web on a moving wire net. Then, this web is partially thermocompressed by passing it through a partial thermocompression bonding apparatus composed of an embossing roll having a roll temperature of 90 ° C., and the basis weight is 100 g each consisting of long fibers having a single yarn fineness of 4.0 denier. / M ² (Example 1), 200 g /
A long-fiber nonwoven fabric having m ² (Example 2) and 300 g / m ² (Example 3) was obtained.

Using the obtained non-woven fabric, a diameter of 30 cm,
A cylindrical bag-shaped root cover for raising seedlings having a height of 30 cm was produced by sewing the joint portion. Then, put this bag-shaped cover in the hole dug in the soil, and then plant a young couscous tree that was grown on the farm in advance in this cover, and after 2 years, dug along the outside of the cover, I brought it to another land and planted it. One year later, the soil was dug up again, and the state of decomposition of the cover and the state of root development were observed. Table 1 shows the observation results at this time and the characteristics of the obtained nonwoven fabric.

Example 4 The web obtained under the same conditions as in Example 1 was partially thermocompressed under the condition of a frequency of 19.5 kHz by using an ultrasonic fusing device, and the single yarn fineness was 4.0. Made of long denier fibers,
A long-fiber nonwoven fabric having a basis weight of 200 g / m ² was obtained.

Using the obtained nonwoven fabric, a root cover for raising seedlings was prepared under the same conditions as in Example 1, and the state of decomposition of the cover and the state of root development were observed. Table 1 shows the observation results at this time and the characteristics of the obtained nonwoven fabric.

Example 5 Using the same polybutylene succinate as in Example 1, melt spinning was carried out from the spinneret at a spinning temperature of 200 ° C. and a single hole discharge rate of 2.2 g / min. After the spun yarn is cooled by a cooling device, it is subsequently pulled and thinned by an aspirator provided below the spinneret at a pulling speed of 2000 m / min, and opened and moved using a well-known opener, and a wire mesh is moved. It was collected and deposited as a web on top. Then, this web is partially thermocompressed by passing it through a partial thermocompression bonding apparatus composed of an embossing roll having a roll temperature of 90 ° C., and the basis weight is 200 g / m 2 which is composed of long fibers having a fineness of 10.0 denier. A long fiber non-woven fabric of ² was obtained.

Using the obtained nonwoven fabric, a root cover for raising seedlings was prepared under the same conditions as in Example 1, and the state of decomposition of the cover and the state of root development were observed. Table 1 shows the observation results at this time and the characteristics of the obtained nonwoven fabric.

Example 6 A masterbatch containing 20% by weight of carbon black based on polycaprolactone having a melting point of 62 ° C. and a melt flow rate of 30 g / 10 min, and a particle diameter of 1 μm based on the polymer. Using a masterbatch containing 15% by weight of talc, 1.0% by weight of each of the pigment and talc in the molten polymer,
The compounding amount is 0.75% by weight, and the spinning temperature is 1
Melt spinning was performed from a rectangular spinneret having 400 holes with a spinning hole diameter of 0.5 mm under the conditions of 90 ° C. and single hole discharge rate of 3.4 g / min. After cooling the spun yarn with a cooling device, subsequently, using a rectangular pulling device provided below the spinneret, pulling and thinning at a pulling speed of 3000 m / min, and opening with a known spreader, It was collected and deposited as a web on a moving wire mesh. Then, this web was partially pre-thermocompressed by being passed through a partial thermocompression bonding apparatus composed of an embossing roll having a roll temperature of 50 ° C. to obtain a long fiber nonwoven fabric composed of long fibers having a single yarn fineness of 10 denier.

Using the obtained nonwoven fabric, a root cover for raising seedlings was prepared under the same conditions as in Example 1, and the state of decomposition of the cover and the state of root development were observed. Table 1 shows the observation results at this time and the characteristics of the obtained nonwoven fabric.

Example 7 AS except that the melting point was 178 ° C. and the temperature was 210 ° C.
A masterbatch containing 20% by weight of carbon black based on poly-L-lactic acid having a melt flow rate value of 20 g / 10 min measured by the method described in TM-D-1238 (E), and the polymer. And a masterbatch containing 10% by weight of talc having a particle diameter of 1 μm as a base, and a pigment and talc are weighed and compounded in the molten polymer to 1.0% by weight and 0.5% by weight, respectively. Then, under the condition of a spinning temperature of 205 ° C., melt spinning is performed from a rectangular spinneret having a spinning hole diameter of 0.4 mm and 680 holes, and is pulled by using a rectangular pulling device, and the roll temperature is set to 1
A long fiber nonwoven fabric having a single yarn fineness of 4 denier was obtained in the same manner as in Example 6 except that the temperature was set to 65 ° C.

Using the obtained nonwoven fabric, a root cover for raising seedlings was prepared under the same conditions as in Example 1, and the state of decomposition of the cover and the state of root development were observed. Table 1 shows the observation results at this time and the characteristics of the obtained nonwoven fabric.

Example 8 Using the long-fiber nonwoven fabric obtained in Example 5, a preheating temperature of 9 was used.
At 0 ℃, mold temperature 80 ℃, mold frame upper diameter 105φ, lower diameter 7
A pot having 5φ, a height of 95 mm and a volume of 621 cc was formed. Using this pot as a root cover for raising seedlings, the state of decomposition of this cover and the state of root development were observed as in Example 1. Table 1 shows the observation results at this time and the characteristics of the obtained nonwoven fabric.

Comparative Example 1 Using polyethylene terephthalate having a melting point of 260 ° C. and an intrinsic viscosity of 0.7, melt spinning was carried out from a spinneret under the conditions of a spinning temperature of 290 ° C. and a single hole discharge rate of 2.3 g / min. After the spun yarn is cooled by the cooling device, the aspirator provided below the spinneret subsequently pulls at a speed of 5200 m.
The fiber was drawn and thinned at a speed of 1 / min, opened using a known opener, and collected and deposited as a web on a moving wire net. Then, this web is partially thermocompressed by passing it through a partial thermocompression bonding apparatus comprising an embossing roll having a roll temperature of 230 ° C.
A long-fiber nonwoven fabric having a single-fiber fineness of 4.0 denier and a basis weight of 200 g / m ² was obtained.

Using the obtained non-woven fabric, a bag-shaped root cover for raising seedlings was prepared under the same conditions as in Example 1, and the state of decomposition of the cover and the state of root development were observed. Table 2 shows the observation results at this time and the characteristics of the obtained nonwoven fabric.

Comparative Example 2 Using rayon of 50 mm with 2.0 denier,
After being introduced into the fiber opening machine, a non-woven web having a basis weight of 200 g / m ² was prepared with a parallel card machine and a cross wrapper. This non-woven web was needle punched using a # 40 regular barb punch needle under the conditions of a needle depth of 11 mm and a punch density of 200 punches / cm ² to obtain a long fiber nonwoven fabric.

Using the obtained nonwoven fabric, a bag-shaped root cover for raising seedlings was prepared under the same conditions as in Example 1, and the state of decomposition of the cover and the state of root development were observed. Table 2 shows the observation results at this time and the characteristics of the obtained nonwoven fabric.

Comparative Example 3 A long fiber nonwoven fabric was obtained in the same manner as in Example 2 except that the basis weight was 400 g / m ² , and a cover was produced. Then, in the same manner as in Example 2, the state of decomposition of the cover and the state of root development were observed. Table 2 shows the observation results at this time and the characteristics of the obtained nonwoven fabric.

Comparative Example 4 A regular round spinneret having a single hole discharge rate of 4.6 g / min and a spinning hole diameter of 0.6 mm was used, a pulling speed was set to 2600 m / min, and a single fiber fineness of 16 denier was obtained. A long fiber non-woven fabric was obtained and a cover was prepared in the same manner as in Example 2 except for the above.
Then, in the same manner as in Example 2, the state of decomposition of the cover and the state of root development were observed. Table 2 shows the observation results at this time and the characteristics of the obtained nonwoven fabric.

Comparative Example 5 Example 2 was repeated except that an ordinary round spinneret having a single hole discharge rate of 0.23 g / min and a spinning hole diameter of 0.3 mm was used to obtain continuous fibers having a single yarn fineness of 0.8 denier. A long-fiber nonwoven fabric was obtained in the same manner as in 1. and a cover was prepared. Then, in the same manner as in Example 2, the state of decomposition of the cover and the state of root development were observed. Table 2 shows the observation results at this time and the characteristics of the obtained nonwoven fabric.

[0067]

[Table 1]

As is clear from Table 1, the non-woven fabric obtained in Example 1 had sufficient mechanical properties as a root cover for raising seedlings and was easy to make into a bag. In addition, since the root cover for raising seedlings using this is a cover made of polybutylene succinate, which is a non-woven fabric with a fineness and a low basis weight, it is completely decomposed in soil after 3 years. It was disassembled. Furthermore, breathability is also good,
The growth condition of the seedlings was also good.

The non-woven fabric obtained in Example 2 had sufficient mechanical properties as a root cover for raising seedlings and was easy to make into bags. In addition, the root cover for raising seedlings using this,
Since the material is polybutylene succinate, which is a cover using a non-woven fabric having a fineness and a fine weight, the decomposition performance in soil was almost completely decomposed after 3 years. Furthermore, the air permeability was good, and the growth condition of the seedlings was also good.

The nonwoven fabric obtained in Example 3 had sufficient mechanical properties as a root cover for raising seedlings, and was easy to make into bags. In addition, the root cover for raising seedlings using this,
Since the material is polybutylene succinate, which is a cover using a non-woven fabric having a fineness and a high basis weight, the decomposition performance in soil was almost decomposed after 3 years. Furthermore, regarding the growth condition of the seedlings, the growth was normal probably because the air permeability was a little low and the rooting was a little poor.

The non-woven fabric obtained in Example 4 had mechanical properties sufficient as a root cover for raising seedlings, though slightly inferior to the non-woven fabrics obtained by embossing in Examples 1-3.
Bag making was also particularly easy. Further, since the root cover for raising seedlings using this was formed from a non-woven fabric that was maintained in shape by ultrasonic processing, it was completely decomposed after 3 years in terms of degrading performance in the soil even though it had a basis weight. . Furthermore, the air permeability was good, and the growth condition of the seedlings was also good.

Since the non-woven fabric obtained in Example 5 has a large single fiber fineness of the constituent fibers, it is slightly inferior to the non-woven fabrics constructed with the fineness of Examples 1 to 3, but it is a machine sufficient as a root cover for raising seedlings. It had the following characteristics and did not cause any major problems in bag making. Further, since the root cover for raising seedlings using this is formed from a non-woven fabric made of fibers of large fineness, the decomposition rate in soil is slightly slower than that in Example 1 and Example 2, but three years later Was almost decomposed. Furthermore, the air permeability was good, and the growth of the seedlings was very good because the rooting was good.

The non-woven fabric obtained in Example 6 was made of polycaprolactone and had a large single yarn fineness as a constituent fiber. However, mechanical properties, air permeability, biodegradability and growth condition of seedlings were satisfactory. Met.

The nonwoven fabric obtained in Example 7 was made of a lactic acid-based polymer, but was satisfactory in mechanical properties, air permeability, biodegradability, and growth of seedlings.

The root cover for raising seedlings obtained in Example 8 was formed by molding the long-fiber nonwoven fabric obtained in Example 5, and by molding, the tensile strength and tear strength of the nonwoven fabric were reduced, and the air permeability was improved. However, it had practical mechanical properties, was satisfactory in biodegradability and in the growth condition of seedlings, and was suitable as a root cover for raising seedlings.

[0076]

[Table 2]

As is clear from Table 2, since the root cover for raising seedlings obtained in Comparative Example 1 uses polyethylene terephthalate as a material, it has excellent mechanical strength, but has no decomposability, and therefore the object of the present invention. It wasn't meant to.

The root cover for raising seedlings obtained in Comparative Example 2 was not suitable as a root cover for raising seedlings because it used rayon as a material, its mechanical strength was slightly low, and its decomposition rate was too fast.

In the root cover for raising seedlings obtained in Comparative Example 3, the nonwoven fabric used had an excessively large basis weight, so that the mechanical strength was satisfactory, but the degradability did not show the target performance. In addition, the growth status of the seedlings also declined.

The root cover for raising seedlings obtained in Comparative Example 4 had a constituent fiber fineness of 16 denier, and although the mechanical strength was satisfactory, the degradability did not show the target performance.

The root cover for raising seedlings obtained in Comparative Example 5 had a constituent fiber fineness of 0.8 denier, and although its mechanical strength was satisfactory, its degradability was too fast, so it was not suitable as a root cover for raising seedlings. It was

[0082]

As described above, according to the present invention, the decomposition rate can be controlled by appropriately adjusting the type of the polymer used, the copolymerization amount ratio, the fiber cross-sectional shape and the like.
Almost no decomposition during seedling raising and almost completely after transplantation, which allows transplanting as it is without needing to remove the root cover while maintaining the mechanical strength necessary for transplanting. A root cover for sex raising seedlings can be provided. Further, since the root cover for raising seedlings of the present invention is formed from a long-fiber nonwoven fabric, it has a three-dimensional network structure and thus has a large surface area, and further exhibits the effect of improving biodegradability. .

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-39260 (JP, A) JP-A-6-335327 (JP, A) JP-A-4-210526 (JP, A) JP-A-5- 168354 (JP, A) JP-A-50-18221 (JP, A) JP-A-63-276425 (JP, A) JP-A-49-47119 (JP, A) Jitsukaihei 4-52436 (JP, U) 63-42061 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) A01G 23 / 00-23 / 14

Claims (6)

(57) [Claims] 1. A root cover for raising seedlings for covering a root part of a plant and soil around the root, wherein the fineness of the biodegradable thermoplastic aliphatic polyester is 1 to 15
50-300 basis weight composed of denier filaments
Made of non-woven fabric of g / m ² and having a basis weight of 100
The tensile strength in terms of g / m ² is 5 kg / 5 cm width or more, the air permeability is 30 cc / cm ² / sec or more, and the thermoplastic aliphatic polyester is polybutylene succinate, polyethylene succinate, For biodegradable nursery, characterized by being any polymer selected from the group of polybutylene adipate and polybutylene sebacate, or a copolymer containing these polymers as main repeating units, or a blend thereof. Root cover. 2. The biodegradable root cover for raising seedlings according to claim 1, wherein a crystal nucleating agent is added to the thermoplastic aliphatic polyester. 3. A root cover for raising seedlings for covering a root portion of a plant and soil around the root, wherein the fineness of the biodegradable thermoplastic aliphatic polyester is 1 to 15
50-300 basis weight composed of denier filaments
Made of non-woven fabric of g / m ² and having a basis weight of 100
The tensile strength in terms of g / m ² is 5 kg / 5 cm width or more, the air permeability is 30 cc / cm ² / sec or more, and the thermoplastic aliphatic polyester is poly (D-lactic acid) and poly (D-lactic acid). Group of (L-lactic acid), copolymer of D-lactic acid and L-lactic acid, copolymer of D-lactic acid and hydroxycarboxylic acid, and copolymer of L-lactic acid and hydroxycarboxylic acid A biodegradable root cover for raising seedlings, which is a polymer selected from the following or a blend thereof, wherein a crystal nucleating agent is added to the thermoplastic aliphatic polyester. 4. A root cover for raising seedlings for covering a root part of a plant and soil around the root, which has a fineness of 1 to 15 made of a biodegradable thermoplastic aliphatic polyester.
50-300 basis weight composed of denier filaments
Made of non-woven fabric of g / m ² and having a basis weight of 100
The tensile strength in terms of g / m ² is 5 kg / 5 cm width or more, the air permeability is 30 cc / cm ² / sec or more, and the thermoplastic aliphatic polyester is polycaprolactone or polypropiolactone. Or a copolymer of these polymers as a main repeating unit, wherein a crystal nucleating agent is added to the thermoplastic aliphatic polyester, which is a biodegradable root cover for raising seedlings. 5. The root cover for biodegradable seedling raising according to any one of claims 1 to 4, which is formed into a bag shape by sewing or heat bonding. 6. The root cover for biodegradable seedling raising according to any one of claims 1 to 4, which is formed into a container by heat molding.