JP2001103845A - Biodegradable foamed pot for raising seedling and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biodegradable foamed pot for raising seedlings, having biodegradability, hardly requiring complicated process for the production, hardly causing root rot of the seedlings and capable of allowing roots to extend well because of proper air permeability and water permeability, and hardly requiring the transplantation of the seedlings from the pot for raising the seedlings, and further to provide a method for producing the pot. SOLUTION: This biodegradable foamed pot for raising the seedlings is obtained by thermally molding an extruded and foamed sheet of a biodegradable resin, produced by extruding a foamable biodegradable resin composition comprising a cellulose acetate-based resin, a biodegradable plasticizer having the melting point lower than the softening point of the resin, and water as a foaming agent, and simultaneously foaming the resin composition by the evaporation and expansion power of the water, to form a cup shape with a bottom having no hole. The method for producing the pot is also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a biodegradable foam growing seedling pot used in the field of agriculture and horticulture and a method for producing the same. More specifically, the present invention relates to a method for producing a cellulose acetate resin as a main raw material by water foaming. The present invention relates to a biodegradable foam growing seedling pot obtained by thermally shaping a biodegradable resin extruded foam sheet into a non-hole bottomed cup shape and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a wide variety of foams made of synthetic resin have been manufactured and utilized in a wide range of fields such as food packaging containers, water purification materials, heat insulating materials, and cushioning materials. recent years,
The demand for these synthetic resin foams tends to increase year by year, and as a result, the amount discarded increases year by year.
As a pollution problem, it has been gaining much public attention. However, recycling of waste synthetic resin foam requires various measures on a social scale, while incineration involves the prevention of harmful gases and the deterioration of incinerators caused by high heat. Therefore, there is a strong demand for the development of a foam that can be easily disposed of.

On the other hand, seedling pots used in the field of agriculture and horticulture also include unglazed pots, peat moss, paper, plastic pots, and seedling raising containers made of nonwoven fabric obtained by thermocompressing a thermoplastic synthetic fiber web. In recent years, in particular, the demand for pots for raising plastic seedlings such as vinyl chloride, polyethylene, polypropylene, and polystyrene has been increasing in recent years from the viewpoint of ease of handling and price. Most of these conventional seedling pots are made of resin such as vinyl chloride or polyethylene, calcium carbonate as an inorganic filler,
It is made by molding aluminum hydroxide and the like. There are also nonwoven fabrics made of recycled fibers of polyester and polypropylene, and those made by press-molding paper chips and crushed wood chips.

However, plastic seedling pots such as polyvinyl chloride and polyethylene used for raising seedlings of vegetables, flowers and the like are not suitable for growing seedlings and the like until the roots become large to some extent and the pot becomes full. However, it is necessary to transplant the seedlings from the seedling pots one by one to transplant them into the field, and it is difficult to transplant the seedlings into the field. In addition, the roots may be damaged and die during transplantation. Also, when pots formed by pressing vinyl chloride or polyethylene resin sheets are used for raising seedlings, these raising seedling pots have no air permeability and water permeability, so a drain hole is formed on the bottom surface,
If water is applied too much, the hole at the bottom of the pot may be blocked or the water permeability may be poor, so that the seedlings may undergo root rot and die. In addition, if the bottom is a hole with a hole in the bottom surface, the soil easily comes out of the pot, so that it takes time and effort to arrange a net or pebbles on the bottom surface. Further, after transplanting the seedlings into the fields, the seedling pots are no longer needed, but the seedling pots made of vinyl chloride or polyethylene resin are difficult to dispose of unless they are reused. For example, when buried in the ground, it does not spoil naturally, but if incinerated, it emits harmful gas, black smoke and high heat, polluting the environment and harming the health of nearby residents, or incineration. The furnace may be damaged. Therefore, recently, there is a demand for a seedling pot composed of a biodegradable material that can be used by directly burying a seedling pot in which seedlings or the like are planted in a wide field, that is, decomposing and disappearing in soil. . In response to the need to develop seedling pots made of biodegradable materials that do not require such disposal and can be buried directly in the main fields, conventional synthetic resins such as polyethylene and polypropylene are biodegraded. There have been various proposals for seedling pots that have been replaced with a sex material. For example, Japanese Patent Application Laid-Open No. 5-199818 discloses a cylindrical or square seedling raising pot made of a biodegradable aliphatic polyester compound or a modified product thereof.
Japanese Patent No. 13682 (Patent No. 2507247) discloses that biodegradation of chitosan or the like is carried out on the surface of a seedling growing pot formed from a nonwoven substrate formed by attaching a biodegradable thermoplastic resin to a fiber web formed of cellulosic fibers as a binder. Seedling pot with a hydrophilic binder attached thereto is disclosed in JP-A-9-2058.
In Japanese Patent Application Laid-Open No. 9-322658, a seedling pot obtained by applying a biodegradable resin such as starch or carboxymethylcellulose as a binder to a nonwoven fabric made of naturally degradable fibers and press-molding the resultant into a pot shape is disclosed in Poly
There has been proposed a seedling pot composed of a net-like material composed of a biodegradable resin such as an aliphatic polyester such as 3-hydroxybutyric acid and a filler.

[0005] However, despite these proposals, the above-mentioned drawbacks have been eliminated, that is, seedlings are transplanted from seedling pots with good ventilation and water permeability without root rot of the seedlings and good rooting. There is no seedling pot that does not need to be used and does not require disposal of used products. Therefore, in particular, disposal is easy,
Development of a seedling pot made of a foam of a biodegradable resin has been strongly desired.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the conventional seedling pots described above, which is biodegradable, does not require complicated steps for production, and has good air permeability. Seedling pot made of a biodegradable resin extruded foam that does not need to be transplanted from a seedling seedling pot, and a method for producing the seedling pot, which does not cause root rot of the seedling and has good root permeability because the seedling root rot is not caused. is there.

[0007]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventors have found that a cellulose acetate resin and a biodegradable plasticizer having a melting point lower than the softening point of the resin are used. A specific foamable biodegradable resin composition containing water as a foaming agent, using a biodegradable resin extruded foam sheet manufactured by extruding and simultaneously foaming by the vaporization and expansion force of water, When heat-shaped into a non-hole bottom cup shape, the air permeability and water permeability are moderate, so the roots of the seedlings do not rot and the rooting is good, and there is no need to transplant the seedlings from the seedling pots. Was easily obtained. The present invention has been completed based on these findings.

That is, according to the present invention, cellulose cellulose
Acetate resin, a foamable biodegradable resin composition containing a biodegradable plasticizer having a melting point at a temperature lower than the softening point of the resin and water as a foaming agent are extruded and simultaneously foamed by the vaporization and expansion of water. Thus, there is provided a biodegradable foam growing seedling pot obtained by subjecting the produced biodegradable resin extruded foam sheet to heat shaping into a holeless bottom cup shape.

Further, according to the present invention, the foamable biodegradable resin composition comprises a cellulose acetate resin (A) 1
00 parts by weight, 10 to 30 parts by weight of the biodegradable plasticizer (B),
And water (C) with respect to 100 parts by weight of the resin component (A + B)
The biodegradable foam raising seedling pot, characterized by containing 3 to 100 parts by weight, or a biodegradable plasticizer,
The above biodegradable foam growing seedling pot or foamable biodegradable resin composition, which is at least one selected from polyalkylene glycol, aliphatic polyester and polycaprolactone, further comprises a biodegradable As a regulator, a photocatalyst is contained, wherein the photocatalyst is a titanium oxide, the foamable biodegradable resin composition further comprises a cellulose acetate-based biodegradable regulator. The above-mentioned biodegradable foam-growing seedling pot or foamable biodegradable resin composition comprising 0.1 to 50 parts by weight of the photocatalyst (D) based on 100 parts by weight of the resin (A), Furthermore, as a foam control agent,
The biodegradable foam raising seedling pot described above is characterized in that it contains 5 to 50 parts by weight of talc (E) based on 100 parts by weight of the cellulose acetate resin (A).

Further, according to the present invention, the extruded biodegradable resin foam sheet is a wrinkled foam sheet having a thickness of 1 to 20 mm, a height of wrinkles of 2 to 10 mm, and an interval of wrinkles of 2 to 2 mm. The biodegradable foam-growing seedling pot according to any one of the above, which is characterized by being 10 to 10 mm.

According to the present invention, on the other hand, a cellulose acetate resin, a biodegradable plasticizer having a melting point lower than the softening point of the resin, and A foamable biodegradable resin composition containing water as a foaming agent is charged, and while the biodegradable resin composition is pushed to the T-die, the temperature is raised to a fluid heating and pressurized state, Thereafter, the extruded foam is extruded from the T-die to produce a biodegradable resin extruded foam sheet, and then the biodegradable resin extruded foam sheet is heat-shaped into a holeless bottom cup shape. And a method for producing the biodegradable foam-growing seedling pot according to any one of the above.

Further, according to the present invention, the foamable biodegradable resin composition comprises a cellulose acetate resin (A) 1
00 parts by weight, 10 to 30 parts by weight of the biodegradable plasticizer (B),
And water (C) with respect to 100 parts by weight of the resin component (A + B)
The method for producing a biodegradable foam raising seedling pot described above, which comprises 3 to 100 parts by weight, or the foamable biodegradable resin composition comprises a cellulose acetate resin 1
It is characterized by further containing 0.1 to 50 parts by weight of a photocatalyst (D) as a biodegradable regulator and / or 5 to 50 parts by weight of talc (E) as a foaming regulator with respect to 00 parts by weight. A method for producing the above biodegradable foam-growing seedling pot is provided.

Furthermore, according to the present invention, the extruded biodegradable resin foam sheet is a wrinkled foam sheet having a thickness of 1 to 20 mm, having a wrinkle height of 2 to 10 mm and a wrinkle interval of 2 mm. A method for producing the biodegradable foam-growing seedling pot described above, which is characterized by having a diameter of 10 mm to 10 mm.

Still further, according to the present invention, the heat shaping includes:
The method for producing a biodegradable foam growing seedling pot according to any one of the above, wherein the method is performed by any of vacuum forming, pressure forming, and press forming.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

1. Cellulose Acetate Resin (A) The cellulose acetate resin (A) used in the biodegradable foam seedling pot of the present invention has a chemical structure close to that of a natural product, so that it can be decomposed by microorganisms in the environment. That is, it has biodegradability and contains cellulose acetate as a main component. The biodegradable resin that may be further blended as an accessory component is not particularly limited, and any one that is generally used as a biodegradable resin can be used. Those corresponding to these include, for example, starch-based, cellulose-based, and the like.

Cellulose acetate contained as a main component in the cellulose acetate resin is usually produced by reacting linter obtained from cottonseed or cellulose of wood pulp with acetic acid. As the cellulose acetate used in the biodegradable foam seedling pot of the present invention, any grade can be used as long as it is generally of a grade commercially available as `` cellulose acetate ''. The degree of acetylation expressed by the weight ratio of acetic acid bound to
It is preferable that the content is 5% or more, and particularly, the degree of acetylation is 47 to
It is preferably 60% (the number of bound acetyl groups per unit of cellulose is 1.9 to 2.8). 45% acetylation degree
If it is less than 3, the melting temperature is too high, and it is difficult to stably melt-mold the foam.

Cellulose acetate has the following physical properties:
It is preferably soft or medium hard, the surface hardness of Rockwell _hardness, those H R = 80 to 100, the impact strength 20
Those with 30 kg-cm / cm are preferably used. Further, from the viewpoint of moldability, those having a softening point (outflow temperature) at which softening starts to flow (outflow temperature) of 150 to 170 ° C.
Load 18.6 kgf / cm ² specified in D 648
A heat deformation temperature of 44 to 55 ° C. under the above conditions is preferably used. On the other hand, with a hard material, it is difficult to stably melt-mold a foam.

The cellulose-acetate resin used for the biodegradable foam seedling pot of the present invention is a cellulose-acetopropionate containing propionic acid or butyric acid in addition to acetate having only an acetic acid group. And also contains cellulose acetobutyrate, melting point,
The mixing ratio of the acid can be appropriately selected and used from the viewpoints of water absorption, solubility in a solvent, and the like. Further, the cellulose acetate foam is generally used for food packaging containers, water purification materials, heat insulating materials, buffers, etc., in order to remove acetic acid odor liberated from the cellulose acetate itself. In many cases, when used in the biodegradable foam seedling pot of the present invention, since acetic acid itself is useful for imparting antibacterial properties, it is necessary to perform a post-treatment to remove acetic acid odor. Alternatively, acetic acid released from cellulose acetate may remain in the foam.

The cellulose acetate resin used in the biodegradable foam growing seedling pot of the present invention has biodegradability. However, there are also cases where the density of microorganisms that degrade it in the natural world, that is, bacteria, is low, and in this case, biodegradation also occurs relatively slowly.
However, by adjusting the material, it is possible to accelerate the decomposition rate including biodegradation. For example, if a photocatalyst (D) is contained as a biodegradable regulator in a biodegradable resin, photodegradation occurs separately from biodegradation in a natural environment subjected to ultraviolet irradiation or the like. The decomposition rate is further accelerated by both biodegradation and photodegradation. Examples of the photocatalyst include known photocatalysts such as titanium oxides, zinc oxide, and cadmium sulfite.
It is chemically stable and inexpensive, and is preferably used. Examples of titanium oxides include titanium oxide ST series for photocatalyst and STS series manufactured by Ishihara Sangyo Co., Ltd. The content of the photocatalyst as a biodegradable regulator in the biodegradable resin can be appropriately increased or decreased as needed. However, usually, the biodegradable resin, that is, the cellulose acetate resin (A) 10
The photocatalyst (D) is used in an amount of 0.1 to 50 parts by weight, preferably 0.5 to 10 parts by weight, based on 0 parts by weight. When the content of the photocatalyst is less than 0.1 part by weight, the photodecomposition effect is too small. On the other hand, when the content is more than 50 parts by weight, the foaming property and the moldability may be affected.

2. Biodegradable plasticizer (B) The specific biodegradable plasticizer (B) component used as an essential component in the biodegradable foam seedling pot of the present invention has a temperature lower than the softening point of the cellulose acetate resin. It is composed of a biodegradable plasticizer having a melting point and is at least one selected from polyalkylene glycols, polyhydric alcohols and polycaprolactone.

Examples of the polyalkylene glycol include polyethylene glycol and polypropylene glycol produced by ring-opening polymerization using ethylene oxide (oxyethylene), propylene oxide (oxypropylene) or a mixture of both as a raw material. It is particularly preferably used from the viewpoint of biodegradability and the like. Further, a monoether, diether, or diol of polyoxyalkylene glycol may be used. Further, the polyoxyalkylene glycol may be a block or random polymerization of oxyethylene and oxypropylene, and the ratio of oxyethylene and oxypropylene is 50% in terms of biodegradability.
% By weight is preferred. The molecular weight of these polyalkylene glycols or polyoxyalkylene glycols is about 20,000 or less, particularly 200 to 2,000.
Is preferred.

Polyhydric alcohols that can be used as biodegradable plasticizers include glycerin, sorbitol,
Examples thereof include 1,3 butanediol, diglycerin, and polyglycerin, which are biodegradable and have a high boiling point.

The polycaprolactone that can be used as a biodegradable plasticizer includes an aliphatic polyester represented by the following general formula. Commercial products of this aliphatic polyester include, for example, Nippon Unicar There is "Tone" (product name) sold by Co., Ltd.

[0025]

Embedded image (In the formula, R represents an aliphatic moiety, and n is a positive integer.)

In the present invention, polycaprolactone used as one of the biodegradable plasticizers is not only biodegradable, but also water-insoluble. Because it has the function of plasticizing the resin, it acts as a plasticizer, and usually without adding any plasticizer required when producing a biodegradable resin foam, a biodegradable resin foam is obtained. In addition, since a water-soluble plasticizer is not used, there is an advantage that it is possible to avoid adverse effects such as dissolution of the plasticizer due to contact with water.

As described above, the specific biodegradable plasticizer used in the present invention must have a melting point not higher than the softening point of the cellulose acetate resin. Among them, the preferred melting point is 100 ° C. or less, and the particularly preferred melting point is around 60 ° C. When a biodegradable plasticizer having such a melting point is added to the biodegradable resin, the boiling point of water in the biodegradable resin increases, so that the foam becomes dense and uniform, and the obtained biodegradable resin is obtained. When the resin extruded foam sheet is thermally shaped, it is possible to easily and easily obtain a high-quality seedling-growing pot having a holeless bottom cup shape. Further, the biodegradable plasticizer improves the impact resistance and improves the property of not scratching the surface of the contents or the seedlings. On the other hand, when a plasticizer having a melting point equal to or higher than the softening point of the cellulose acetate resin, for example, a high molecular weight polyethylene glycol or polycaprolactone is used, even if it is biodegradable, it does not function to plasticize, so that good plasticity is not obtained. Degradable resin foam cannot be obtained.

In the present invention, the blending amount of the biodegradable plasticizer (B) is 100% of the cellulose acetate resin (A).
20 to 50 parts by weight, preferably 25 to 50 parts by weight with respect to parts by weight
It is important that the range be 45 parts by weight. The amount is 2
If the amount is less than 0 parts by weight, the function of plasticizing the cellulose acetate resin is poor, and a satisfactory foam cannot be obtained. On the other hand, if it exceeds 50 parts by weight, its plasticizing effect becomes excessive. In particular, when the amount of the biodegradable plasticizer (B) is within the range of 25 to 45 parts by weight, the obtained foam has a wrinkled sheet shape. The water permeability is moderate and the roots of the seedlings do not rot. In addition, good watering can be achieved even with a small amount of water. Furthermore, because the breathability is in a communicating state,
Oxygen can also flow from the side of the seedling raising pot, and the rooting may be improved.

3. Foamable biodegradable resin composition As described above, the foamable biodegradable resin composition used in the biodegradable foam seedling pot of the present invention is prepared by adding a predetermined amount of a specific biodegradable resin to a cellulose acetate resin (A). It is prepared by mixing a decomposable plasticizer (B) and water (C) as a foaming agent. The mixing ratio of water as a foaming agent is based on 100 parts by weight of the resin component (A + B) of the cellulose acetate resin (A) and the biodegradable plasticizer (B).
It is 3 to 100 parts by weight, preferably 5 to 50 parts by weight.
The amount of water as the foaming agent, like the amount of the biodegradable plasticizer, is an important factor in producing a wrinkled foam sheet, which is a preferred embodiment of the present invention. If the obtained foam is not a wrinkled sheet but a deformed rose or a wrinkle-free sheet, by increasing the amount of water added, the foaming is optimized, and the wrinkled sheet is Can be

As described above, the biodegradable resin composition used in the present invention contains at least one selected from polyalkylene glycols, polyhydric alcohols, and polycaprolactone as a biodegradable plasticizer. However, if necessary, other plasticizers may be added as long as the object of the present invention is not impaired. As a plasticizer,
By heating, if it plasticizes the biodegradable resin,
Although not particularly limited, for example, when the biodegradable resin is a cellulose acetate resin, phthalic acid esters such as methyl phthalate, phosphates such as tributyl phosphate, dioctyl sebacate and dioctyl adipate are used. Basic acid esters and the like are appropriately selected. However, when this plasticizer is added, special care must be taken because the foam may not be formed into a wrinkled sheet. In such a case, the foam can be appropriately formed into a wrinkled sheet by making the specific biodegradable plasticizer or the plasticizer to be added low in viscosity.

Further, the biodegradable resin composition may contain other additives and the like as long as the object of the present invention is not impaired. Examples thereof include a heat stabilizer, a foam control agent, and a foaming aid. ,
And the like. Among them, talc, silicon oxide, titanium oxide (having a larger particle size than that for photocatalyst), magnesium oxide, aluminum oxide, inorganic fine particles such as calcium silicate, cellulose powder, chitin, chitosan,
Wood flour, a foaming regulator such as organic fine particles such as metal stearate, particularly talc, can impart a suitable foaming property to the biodegradable resin composition, so that it is uniformly and highly foamed. A foam is easily obtained. Such foam control agents may be used alone or in combination of two or more. Further, for the purpose of improving foamability, neutralizing acidic substances by-produced during foam production and generating gas, for example, inorganic hydrogen such as sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, potassium carbonate, calcium carbonate, etc. Fine particles may be used in combination. In addition, okara, wood flour, fu (wheat skin), rice flour, starch, corn starch, soft ferrite, waste paper, and the like can also be added as fillers.

As a preferred embodiment of the biodegradable resin composition used in the present invention, a cellulose acetate resin is mixed with a specific biodegradable plasticizer, talc as a foaming regulator, and water as a foaming agent. A degradable resin composition may be used, and the above-mentioned extender may be added to the biodegradable resin composition. The blending amount of talc (E) as a foaming regulator with respect to the biodegradable resin composition is as follows:
It is in the range of 5 to 50 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of the cellulose acetate resin (A). If the blending amount is less than 5 parts by weight, the effect of blending talc does not appear, and an uneven and coarse foam is easily formed. On the other hand, if it exceeds 50 parts by weight, secondary aggregation of talc tends to occur, Again, uneven and coarse foams are likely to be formed.

4. Extruded Biodegradable Resin Foam Sheet and Method for Producing the Same The extruded biodegradable resin sheet used in the seedling raising pot of the present invention is obtained by extruding the foamable biodegradable resin composition from a T-die and simultaneously removing water. It is manufactured by foaming by the vaporizing expansion force. Therefore, the biodegradable foam raising seedling pot of the present invention is characterized in that the biodegradable resin is constituted by one containing cellulose acetate as a main component, and further has the following features. . Foamed with water. Since all the materials are biodegradable, various disposal treatments can be dealt with as compared with general-purpose plastic foam or seedling pots made of vinyl chloride or polyethylene resin. Because of an appropriate communication state, that is, appropriate air permeability and water permeability, the rooting is good without causing root rot of the seedlings. Since the biodegradable resin contains cellulose acetate as a main component, the biodegradable resin is excellent in antibacterial properties and can be expected to impart disease resistance or insecticidal properties to seedlings as seedling raising pots. Compared to starch-based biodegradable resin foams and the like, impact performance does not fluctuate due to atmospheric humidity and is excellent in strength, and is suitable as a seedling pot.

The above-mentioned extruded biodegradable resin foam sheet is
As described above, the foaming biodegradable resin composition is manufactured by extruding and foaming by the vaporization and expansion of water at the same time as extruding the foaming biodegradable resin composition. The manufacturing method is described in detail below. A foamable biodegradable resin composition containing a cellulose-acetate-based resin, a specific biodegradable plasticizer and water (foaming agent) is prepared at a predetermined ratio, and then has a cylindrical container having a T-die in front. (For example, a kneading extruder). As a method of introducing water into the cylindrical container, a predetermined amount of water may be contained in the biodegradable resin composition for foaming in advance, or a biodegradable resin or a specific biodegradable plastic may be added. The water itself may be added directly into the hopper together with the biodegradable resin composition of the agent, or the biodegradable resin composition and moisture may be supplied together. Further, as described above, the charging ratio is determined by the resin component (A +
It is desirable that the water (C) is 3 to 100 parts by weight, preferably 5 to 50 parts by weight, per 100 parts by weight of B).
Next, the biodegradable resin composition is heated to 120 to 250 ° C., preferably 180 ° C. before being pushed to the T-die.
The mixture is heated, melted and kneaded at a temperature of about 220 ° C., and as a result, after being heated and pressurized in a fluid state, is extruded from a T-die having a lip width or a pore diameter of 0.5 to 5 mm, for example. The melt-kneading time cannot be determined unequivocally because it varies depending on the discharge amount per unit time, the melt-kneading temperature, and the like, but may be any time long enough to uniformly melt-knead the mixture. Further, the temperature of the T-die of the discharge section may be the same as the melting and kneading temperature, but may be lower than the temperature within a range where discharge is possible. Here, the extruder used for melt kneading is under high temperature and high pressure, as long as the water is forcibly dissolved in the cellulose acetate,
Although any type of extruder may be used, a single-screw or twin-screw extruder is usually used. Thereafter, the molten biodegradable resin composition discharged from the T-die is
The foaming start position differs depending on the temperature and moisture content,
Normally, foaming is started from a position about 0.1 mm away from the die part, and after foaming is completed, a wrinkled sheet-like foam conforming to the shape of the extrusion port is formed without a secondary molding step. Can also be obtained. The shape of the extrusion port of the T-die is usually square, but depending on the use and purpose of the seedling raising pot,
Porous or irregularly shaped ones may also be used, and may be appropriately selected.

The extruded biodegradable resin sheet of the present invention is a wrinkled sheet-like foam having a thickness of 1 to 3.
20mm, wrinkle height 2-10mm, wrinkle spacing 2
It is preferably from 10 to 10 mm. Sheet thickness is 1m
If it is less than m, it is not preferable because it takes time and cost to prepare a seedling pot having a bottomless cup shape from the foam, and also the strength of the seedling pot obtained is inferior. On the other hand, if the thickness of the sheet is larger than 20 mm, it is not preferable because the handleability is poor. If the height of the wrinkles is less than 2 mm, the elongation at the time of molding is small, and a seedling pot having a holeless bottom cup shape cannot be obtained, and tearing occurs. On the other hand, if it is larger than 10 mm, the gap is too large during vacuum forming and cannot be absorbed.
Even in the case of press molding, a plurality of wrinkles are not uniformly stretched, but only a specific portion is stretched. If the interval between the wrinkles is smaller than 2 mm, the broken portion is weakened, and tearing is likely to occur during molding. In addition, when it exceeds 10 mm, the number of wrinkles contributing to elongation decreases,
Tear is likely to occur. The shape of the wrinkles can be adjusted by appropriately setting the amount of water added to the raw material, the resin discharge amount from the die, and the discharge opening width of the die, but it is important to use water as a foaming agent. . That is, the foamed sheet discharged from the die is rapidly cooled and solidified by the latent heat of evaporation of water, so that the spread of the sheet in the width direction due to foaming is suppressed, and wrinkles can be formed. The formed wrinkles are extremely useful in forming a sheet. That is, the sheet obtained by extrusion foaming has insufficient flexibility to be formed into a cup shape having no hole and a seedling pot as it is, but by forming wrinkles, the wrinkles are formed at the time of forming. It becomes possible to obtain a molded product of a seedling growing pot having a cup shape with no hole and bottom, which compensates for the lack of elongation and flexibility.

5. Biodegradable foam raising seedling pot and molding method thereof The biodegradable foam raising seedling pot of the present invention heats a biodegradable resin extruded foam sheet, which is a wrinkled sheet-like foam, into a holeless bottom cup shape. Manufactured by shaping. The heat shaping can be appropriately selected from vacuum forming, pressure forming, press forming and the like which are usually used as a means for forming a sheet material in the plastic field. However, among them, in the case of the present invention, since the biodegradable resin extruded foam sheet has wrinkles, air leakage is likely to occur, and further, the biodegradable resin extruded foam sheet itself also transmits air. From an easy point, the whole sheet is heated on average,
It is preferable to form a pot having a bottomless cup shape by press molding such as pressing a mold or sandwiching the mold between upper and lower molds when the entire sheet is somewhat softened. The biodegradable foam growing seedling pot obtained by the present invention has various features and advantages as described above. That is, it is biodegradable,
Even with incineration, there is no problem of toxic gas or incinerator deterioration,
Moreover, as a seedling pot, it does not decompose during the seedling raising period, makes it possible to disintegrate it in the soil after use, and because the permeability and water permeability are moderate, the rooting is good without causing root rot of the seedlings, There is no need to transplant the seedlings from the seedling pots, and since they have a holeless bottom cup shape, there is no need to place a net or pebbles on the bottom surface. Therefore, the biodegradable foam-growing seedling pot obtained by the present invention can be widely used for various uses as a seedling-growing pot or a tree-growing pot taking advantage of these characteristics.

[0037]

The present invention will be described below in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0038] Examples 1-3 Example 1 [Production of the biodegradable resin extruded foam sheet] as biodegradable resins, soft Teijin Co. cellulose diacetate (surface hardness (H _R): 8
5. Impact strength: 25 kgf · cm / cm ² , Outflow temperature:
155 ° C., heat deformation temperature: 48 ° C., degree of acetylation: 57%) (reference: 100 parts by weight), and polycaprolactone (trade name: T, sold by Nippon Unicar Co., Ltd.) as a biodegradable plasticizer
ONE polymer P-767, melting point: 60 ° C, density:
1.145 g / cm ³ , molecular weight: 40,000) (40 parts by weight), and talc (14 parts by weight) as a foaming regulator was added to obtain a biodegradable resin composition. After adding water (31 parts by weight) and supplying it to a hopper of a kneading extruder, heating and kneading at a temperature of 180 ° C., a T having a die width of 500 mm and a lip width of 4 mm is used.
It was extruded from the die to obtain a foam sheet of a biodegradable resin. The extruded biodegradable resin sheet thus obtained was in the form of a wrinkled sheet as shown in FIG. The composition is shown in Table 1. Example 2 shows that, as a biodegradable plasticizer, polycaprolactone was used instead of polycaprolactone with a molecular weight of 1,000.
A foam sheet of a biodegradable resin was obtained in the same manner as in Example 1, except that polyethylene glycol (40 parts by weight) was used. The extruded biodegradable resin sheet thus obtained was also in the form of a wrinkled sheet as shown in FIG. The composition is shown in Table 1. Example 3 uses polyethylene glycol (40 parts by weight) having a molecular weight of 1,000 instead of polycaprolactone as a biodegradable plasticizer, and further uses a powdered titanium oxide photocatalyst A (ST Ishihara Techno Co., Ltd.) as a photocatalyst.
-01; X-ray particle size = 7 nm) except that 1.0 part by weight was used to obtain a biodegradable resin foam sheet in the same manner as in Example 1. The extruded biodegradable resin sheet thus obtained was also in the form of a wrinkled sheet as shown in FIG. The composition is shown in Table 1.

Examples 4 to 6 [Molding of Biodegradable Foam Raising Seedling Pot] The entire biodegradable resin extruded foam sheets obtained in Examples 1 to 3 were heated on average, and At the time of softening, press molding was performed by pressing a mold to form a pot having a holeless bottom cup shape. A biodegradable foam growing seedling pot as shown in FIG. 2 was obtained.

[0040]

[Table 1]

Comparative Example 1 [Production of Extruded Biodegradable Resin Foam Sheet and Molding of Foam Seedling Pot] After obtaining a wrinkled sheet, the sheet was heated and calendered.
Except for using the sheet from which the wrinkles were eliminated, the same procedure as in Example 1 was performed. The extruded biodegradable resin sheet from which the wrinkles have been removed is press-molded in a mold in the same manner as in Examples 4 to 6, to obtain a biodegradable foam seedling pot having a non-hole bottom cup shape. Was.

[0042]Comparative Example 2  Comparative Example 2 was manufactured by thermoforming a polyethylene sheet.
A commercially available seedling pot made of polyethylene
You.

With respect to the five types of seedling pots obtained in Examples 4 to 6 and Comparative Examples 1 and 2, moldability, shape retention, decomposability when buried in soil, air permeability, water permeability, plant Table 1 shows the results of an investigation on the degree of influence on (pertussis).

From these evaluation results, Examples 4 to 6 were:
For Comparative Examples 1 and 2, moldability. It has excellent shape retention and excellent breathability and water permeability.
It was found that the plants had a decomposition period that had no effect on raising seedlings. In particular, Example 6 has a photocatalytic effect and decomposes in a relatively short period of time.

[0045]

EFFECT OF THE INVENTION The biodegradable foam growing seedling pot of the present invention comprises:
Cellulose-acetate-based resin, a biodegradable resin blend obtained by blending a specific amount of a specific biodegradable plasticizer having a melting point lower than the softening point of the resin as a raw material, and a special foam using water as a foaming agent By applying the foam manufacturing method, a foamed sheet having wrinkles can be easily formed into a holeless bottom cup shape by heat or the like. The seedling raising pot does not decompose during the seedling raising period and has biodegradability, so there is no need for incineration after use, and the pot easily disintegrates in soil.
Therefore, it is free from the release of harmful substances due to incineration, damage to the incinerator and the like, and there is no risk of natural pollution. Furthermore, since the air permeability and the water permeability are moderate, the roots of the seedlings do not rot and the rooting is good, so that complicated work such as transplantation, which is indispensable for conventional seedling pots made of polyethylene or the like, is not required. Since it does not damage the roots, it has various excellent effects such as no need to worry about poor growth or death.

[Brief description of the drawings]

FIG. 1 is a diagram showing a wrinkled biodegradable resin extruded foam sheet produced according to Examples 1 to 3 of the present invention.

FIG. 2 is a view showing a biodegradable foam-growing seedling pot in the form of a cup without a bottom, which is manufactured according to Examples 4 to 6 of the present invention;
(A) is a perspective view, (b) is a sectional view.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65D 1/26 C08J 9/12 CEP 4J002 C08J 9/12 CEP C08K 3/22 C08K 3/22 3/34 3 / 34 5/053 5/053 C08L 1/12 ZAB C08L 1/12 ZAB C12N 1/00 P // C12N 1/00 B29K 1:00 B29K 1:00 105: 04 105: 04 B29L 22:00 B29L 22: 00 B65D 1/00 ACF term (reference) 2B027 NC25 NC40 NC52 ND09 NE05 SA13 SA25 UB26 3E033 AA08 BA10 BA13 BB04 CA20 DA08 DC03 DD01 FA10 GA03 4B065 AA01X BB06 BB12 BB18 BC31 BC37 CA54 4A0724 AA02A68AC68A68A BC01 CA22 CC03X CC04X CC22X CC32X DA23 DA34 DA46 DA59 4F208 AA01K AB02 AB07 AC03 AG03 AG04 AG23 AH55 AR12 AR13 MA01 MA02 MA05 MB01 MG01 MG13 MG22 MH06 MJ09 4J002 AB0 21 CF192 CH022 DE026 DE108 DE138 DG018 DJ049 EC057 FD010 FD022 FD027 FD208 FD209 FD326 GA00 GG01

Claims (13)

[Claims] 1. A foamable biodegradable resin composition containing a cellulose acetate resin, a biodegradable plasticizer having a melting point lower than the softening point of the resin and water as a foaming agent, and simultaneously extruding water. A biodegradable foam seedling pot obtained by heat-forming a biodegradable resin extruded foam sheet produced by foaming with the vaporizing expansion force of the above into a non-hole bottom cup shape. 2. The foamable biodegradable resin composition comprises 100 parts by weight of a cellulose acetate resin (A), 10 to 30 parts by weight of a biodegradable plasticizer (B), and a resin component (A + B).
The biodegradable foam-grown seedling pot according to claim 1, wherein the pot contains 3 to 100 parts by weight of water (C) per 100 parts by weight. 3. The biodegradable plasticizer according to claim 1, wherein the biodegradable plasticizer is at least one selected from polyalkylene glycols, polyhydric alcohols, and polycaprolactone. Foam raising seedling pot. 4. The foamable biodegradable resin composition further comprises:
The biodegradable foam growing seedling pot according to claim 1, wherein a photocatalyst is contained as a biodegradability regulator. 5. The pot for growing biodegradable foams according to claim 4, wherein the photocatalyst is a titanium oxide. 6. The foamable biodegradable resin composition further comprises:
3. The biodegradable foam according to claim 2, wherein the biodegradable regulator contains 0.1 to 50 parts by weight of the photocatalyst (D) based on 100 parts by weight of the cellulose acetate resin (A). 4. Seedling pot. 7. The foamable biodegradable resin composition further comprises:
7. The biodegradable foam according to claim 2, wherein the foaming regulator contains 5 to 50 parts by weight of talc (E) based on 100 parts by weight of the cellulose acetate resin (A). 8. Seedling pot. 8. The extruded biodegradable resin foam sheet is a wrinkled foam sheet having a thickness of 1 to 20 mm, wherein the height of the wrinkles is 2 to 10 mm and the interval between the wrinkles is 2 to 10 mm. The biodegradable foam-growing seedling pot according to claim 1. 9. A cylindrical container having a T-die in front thereof contains a cellulose acetate resin, a biodegradable plasticizer having a melting point lower than the softening point of the resin, and water as a foaming agent. Inject the foamable biodegradable resin composition,
While the biodegradable resin composition is being pushed to the T-die, the temperature is raised to a fluid heating and pressurized state, and then the foam is extruded and foamed from the T-die to form an extruded biodegradable resin foam sheet. The biodegradable foam-grown seedling pot according to any one of claims 1 to 8, wherein the biodegradable resin extruded foam sheet is manufactured and then heat-shaped into a holeless bottom cup shape. Production method. 10. The foamable biodegradable resin composition comprises 100 parts by weight of a cellulose acetate resin (A), 10 to 30 parts by weight of a biodegradable plasticizer (B), and a resin component (A +
The method for producing a biodegradable foam-growing seedling pot according to claim 9, wherein B) contains 3 to 100 parts by weight of water (C) per 100 parts by weight. 11. The foamable biodegradable resin composition is further added with a photocatalyst (D) 0.1 to 50 as a biodegradability regulator based on 100 parts by weight of the cellulose acetate resin (A).
Parts by weight, and / or talc (E) 5 as a foam control agent
The method for producing a biodegradable foam raising seedling pot according to claim 10, comprising 50 parts by weight. 12. The extruded biodegradable resin sheet is a wrinkled foam sheet having a thickness of 1 to 20 mm, wherein the height of the wrinkles is 2 to 10 mm and the interval between the wrinkles is 2 to 10 mm. A method for producing a biodegradable foam-growing seedling pot according to any one of claims 9 to 11. 13. The biodegradable foam raising seedling pot according to claim 9, wherein the heat shaping is performed by any one of vacuum forming, press forming, and press forming. Manufacturing method.