JP2807399B2 - Soil conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to provisional soil specific gravity (removal of water from soil,
The present invention relates to a soil improving material for reducing the apparent specific gravity when dried and improving drainage, water retention, and air permeability. The present invention also relates to the effective use of the waste of the aliphatic polyester resin molded article after being used as a molded article, sheet, film or the like.

[0002]

2. Description of the Related Art When agricultural fertilizers are used for a long time as agricultural soil, the soil becomes cultivated (the soil becomes a hard soil with a high density and loses drainage and air permeability). , The soil deteriorates. For such soils, organic fertilizers such as fallen leaves, straw, and Thai manure can be used.However, the reduction of livestock such as cattle and horses due to the introduction of tillers by farmers, etc.
Due to the mechanization of rice harvesting, the decrease in fertilization of rice straw in Thailand and the aging of the agricultural population have made it difficult to obtain these organic fertilizers. It has been rare.

[0003] Soil improving materials for such purposes include shirasu balloon, obsidian pearlite, vermiculite, cultivated soil, etc., all of which reduce the temporary specific gravity of the soil.
Although they have the effect of improving drainage, water retention, and air permeability, these effects do not improve over time because they retain their original shape.

[0004] On the other hand, conventional plastic waste is
Landfill as its treatment method, had to rely on incineration, but the aliphatic polyesters targeted by the present invention are biodegradable, while being a synthetic polymer as a specific property, It was noted as a plastic that can be easily disposed of.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to an organic-microbial decomposable soil improving material, which is mixed with soil to reduce the temporary specific gravity of the soil and improve drainage, water retention and air permeability. At the same time, by the decomposition of the soil conditioner by living organisms, it is possible to generate additional pores in the soil and promote a decrease in the provisional specific gravity, and the soil conditioner causes waste treatment to lead to environmental pollution. The purpose is to develop a method that can effectively dispose of plastic waste and other wastes.

[0006]

The present invention relates to (1) a polyether having a number average molecular weight of 5,000 or more mainly from glycol and an aliphatic dibasic acid or a derivative thereof.
Synthesizing a ster prepolymer, the polyester prepoly
0.1 to 5 parts by weight per 100 parts by weight of
Use a pulling agent to make the number average molecular weight 10,000 or more
(2) a soil improving material comprising a granular material of a biodegradable aliphatic polyester resin, (2) a molded product, a foam, a sheet, a film,
Microbial degradable aliphatic polyester obtained by crushing a molded product such as yarn to a degree that passes through a sieve with an opening of 10 mm
The soil-improving material according to the above (1), which is a biodegradable aliphatic polyester resin obtained by molding the resin or the pulverized product into pellets ; and (3) the biodegradable aliphatic polyester resin ,
A micro-biodegradable fillers or mineral soil modifier The compounded above (1) or (2) fine things degradable soil conditioner excellent by developing a soil conditioner according, also this plastic The two objectives of waste disposal were achieved at the same time.

The aliphatic polyester resin mainly synthesized from glycol and an aliphatic dibasic acid or a derivative thereof, which is an object of the present invention, is excellent in physical properties, and therefore, is an injection molded product by injection molding, extrusion molding or the like. ,pipe,
Various molded or foamed materials such as sheets, films, fibers, etc.
Alternatively, it is used in a wide range of applications as a secondary molded article obtained by vacuum molding, pressure molding, or the like from a sheet or film.

The aliphatic polyester resin referred to in the present invention is mainly composed of a polyester synthesized mainly from glycols and an aliphatic dibasic acid or a derivative thereof. Is obtained by synthesizing a relatively high-molecular-weight polyester prepolymer having a hydroxyl group, and then coupling these prepolymers with a coupling agent.

Heretofore, a low molecular weight polyester prepolymer having a hydroxyl group at the terminal group and having a number average molecular weight of 2,000 to 2,500 has been reacted with diisocyanate to form a polyurethane, which has been used as a rubber, foam, paint and adhesive. It is widely done.

However, the polyester prepolymer used for these polyurethane foams, paints and adhesives is a low molecular weight prepolymer having a number average molecular weight of 2,000 to 2,500. In order to obtain practical physical properties as a polyurethane, the amount of diisocyanate used should be 1 to 100 parts by weight of the low molecular weight prepolymer.
It is necessary to be 0 to 20 parts by weight. When such a large amount of diisocyanate is added to a molten low-molecular-weight polyester having a temperature of 150 ° C. or higher, gelation occurs, and a melt-moldable resin cannot be obtained.

Also, as in the case of polyurethane rubber,
A method of converting a hydroxyl group into an isocyanate group by adding a large amount of diisocyanate and further increasing the number average molecular weight with glycol can be considered, but the amount of diisocyanate used is reduced as described above. Polymer 10
10 parts by weight or more is required for 0 parts by weight. At this time, if a heavy metal catalyst is used in the synthesis of the polyester, the reactivity of the isocyanate group is remarkably promoted, resulting in poor storage stability, cross-linking reaction, branch formation, and loss of meltability. Need to be synthesized, so that the number average molecular weight is at most 2,500
Is the limit.

The polyester prepolymer for obtaining the aliphatic polyester resin used in the present invention has a terminal group obtained mainly by reacting a glycol with an aliphatic dibasic acid or a derivative thereof, substantially having a hydroxyl group. Number average molecular weight is 5,000 or more, preferably 1
It is a saturated aliphatic polyester having a relatively high molecular weight of 000 or more and a melting point of 60 ° C. or more.

When the number average molecular weight is less than 5,000,
Even if a small amount of the coupling agent of 0.1 to 5 parts by weight is used, an aliphatic polyester resin having good physical properties cannot be obtained. The polyester prepolymer having a number average molecular weight of 5,000 or more has a hydroxyl value of 30 or less, and does not form a gel during the reaction even under severe conditions such as a molten state by using a small amount of a coupling agent. A polyester resin can be synthesized.

As the glycol used, for example, ethylene glycol, 1,4-butanediol, 1,6-
Hexanediol, decamethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol and the like can be mentioned. Ethylene oxide can also be used. These glycols may be used in combination.

The aliphatic dibasic acids or derivatives thereof which form aliphatic polyester resins by reacting with glycols include succinic acid, adipic acid, suberic acid, sebacic acid,
There are lower alcohol esters such as dodecane diacid, succinic anhydride, adipic anhydride and dimethyl ester thereof, which are commercially available and can be used in the present invention. Polybasic acids or derivatives thereof may be used in combination.

These glycols and dibasic acids or derivatives thereof are mainly composed of aliphatic compounds, but are used in combination with a small amount of a polyfunctional component, for example, a trifunctional or tetrafunctional polyhydric alcohol, oxycarboxylic acid or polycarboxylic acid. Is preferred.

The trifunctional polyhydric alcohol component is typically trimethylolpropane, glycerin or its anhydride, and the tetrafunctional polyhydric alcohol component is pentaerythritol.

As the trifunctional oxycarboxylic acid, malic acid is practically advantageous, and as the tetrafunctional oxycarboxylic acid component, citric acid is practical because a commercially available product can be easily obtained at low cost.

As the trifunctional polyvalent carboxylic acid (or acid anhydride) component, for example, trimesic acid, propanetricarboxylic acid and the like can be used, but trimellitic anhydride is advantageous in practical use.

Examples of the tetrafunctional polycarboxylic acid (or an acid anhydride thereof) include pyromellitic anhydride, benzophenonetetracarboxylic anhydride, cyclopentanetetracarboxylic anhydride and the like.

The proportion of the polyfunctional component used is such that the mole number of either the glycol component or the aliphatic (including cycloaliphatic) dibasic acid (or derivative thereof) component is 100 mol%.
On the other hand, in the case of a trifunctional component, it is 5 mol% or less, preferably 0.5 mol% or more and 3 mol% or less, and in the case of a 4-functional component, it is 3 mol% or less, preferably 0.2 mol% or more. Mol% or less.

If the proportion of the trifunctional component is more than 5 mol%, or if the proportion of the tetrafunctional component is more than 3 mol%, the risk of gelling during the esterification reaction is significantly increased.

The polyester prepolymer for the aliphatic polyester resin used in the present invention has a terminal group substantially having a hydroxyl group. For this purpose, glycol and aliphatic dibasic acid (or a derivative thereof) used in the synthesis reaction are used. The proportion used requires a slight excess of glycol.

In order to synthesize a polyester prepolymer having a relatively high molecular weight, it is necessary to use a deglycol-reaction catalyst during the deglycolization reaction following the esterification.

Examples of the glycol removal catalyst include acetoacetoyl-type titanium chelate compounds, titanium compounds such as organic alkoxytitanium compounds, and metal salts of organic acids. These titanium compounds and metal salts of organic acids can be used in combination. Examples of these include diacetacetoxyoxytitanium (“Nasem Titanium” manufactured by Nippon Chemical Industry Co., Ltd.), tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, calcium stearate and the like. The use ratio of the deglycol reaction catalyst is from 0.001 to 1 part by weight, preferably from 0.01 to 1 part by weight, based on 100 parts by weight of the polyester prepolymer.
0.1 parts by weight. The deglycol reaction catalyst may be added from the beginning of the esterification, or may be added immediately before the deglycol reaction.

As a result, the polyester prepolymer usually has a number average molecular weight of 5,000 or more, preferably 20,000.
A material having a melting point of 0 or more and a melting point of 60 ° C. or more can be easily obtained, and it is more preferable that the material has crystallinity.

When the aliphatic polyester resin of the present invention is used as a plastic raw material, the number average molecular weight is preferably 5,000 or more, and more preferably 10,000.
In order to further increase the number average molecular weight, a coupling agent is used for the polyester prepolymer having a terminal group substantially having a hydroxyl group.

Examples of the coupling agent include diisocyanates, oxazolines, diepoxy compounds, acid anhydrides, etc., with diisocyanates being particularly preferred.

In the case of an oxazoline or diepoxy compound, it is necessary to react a hydroxyl group with an acid anhydride or the like and convert the terminal into a carboxyl group before using a coupling agent.

The diisocyanate is not particularly limited,
For example, 2,4-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate And hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. Hexamethylene diisocyanate is particularly preferable in terms of the color of the formed resin, reactivity when adding polyester, and the like.

The addition amount of these coupling agents is 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight based on 100 parts by weight of the polyester prepolymer.

If the amount is less than 0.1 part by weight, the coupling reaction is insufficient, and if it exceeds 5 parts by weight, gelation occurs.

The addition is desirably carried out under conditions in which the polyester prepolymer is in a homogeneous molten state and can be easily stirred. It is not impossible to add to the solid polyester prepolymer and melt and mix through an extruder, but it is added to the aliphatic polyester resin production equipment or to the molten polyester prepolymer (for example, in a kneader). It is practical to do.

In this case, the aliphatic polyester resin has a number average molecular weight of 10,000 or more, whereby the aliphatic polyester resin and the aliphatic polyester resin composition have sufficient mechanical properties. Become.

The soil modifying material may be produced directly from such an aliphatic polyester resin. However, by using the aliphatic polyester resin product waste as a raw material, the waste is used as a raw material for the soil improving material. be able to.

As the soil improving material, a granular material obtained by crushing a molded product and passing through a sieve having an opening of 10 mm may be used as it is. Further, it may be remelted and extruded into a pellet.

In particular, when it is desired to efficiently reduce the weight of the soil (reduce the provisional specific gravity), it is preferable to use a modifier which is obtained by pulverizing a foam or mixing a foaming agent and re-melting to produce granules.

When remelting and granulating, biodegradable fillers such as wood flour, straw, bone meal, oily scum, guano, etc. may be mixed in, or mineral soil improvement such as shirasu balloon, perlite, vermiculite may be performed. Materials can also be mixed.

[0039]

The present invention has excellent properties in physical properties and is used as a waste treatment of a biodegradable aliphatic polyester resin molded product, which is granulated and mixed with the soil to lower the temporary specific gravity of the soil and to reduce drainage. It is intended to improve water resistance, water retention and air permeability.

In particular, by making the soil improving material a foam, the temporary specific gravity of the soil can be more effectively reduced.

The improved material is consumed in the soil in six months due to the decomposition of microorganisms, bacteria and fungi in the soil,
It completely disappears in 1.5 to 2 years and forms many cavities in the soil. Therefore, the distribution effect of water and air does not decrease with time, but rather increases, and has a great effect on the supply of water and air necessary for promoting root elongation of plants. The mixing amount with the soil varies depending on the soil quality, so it cannot be unconditionally determined. However, by mixing the soil with the soil in a range such that the provisional specific gravity of the soil containing the improving material becomes 0.84 to 1.2, Improves the flow of water and air, and consequently promotes the elongation of the roots of the plants and thus the growth of the plants.

[0042]

【Example】

(Example 1) After replacing a 700 L reactor with nitrogen,
183 kg of 1,4-butanediol, 224 k of succinic acid
g. The temperature was increased in a nitrogen stream, and 192
At 220 ° C. for 3.5 hours, further stopping nitrogen and
The esterification reaction by dehydration condensation was performed under reduced pressure of 2 mmHg for 3.5 hours. The collected sample had an acid value of 9.2 mg / g, a number average molecular weight (Mn) of 5,160,
The weight average molecular weight (Mw) was 10,670.
Subsequently, 34 g of tetraisopropoxytitanium as a catalyst was added under a nitrogen stream at normal pressure. 4. Raise the temperature and reduce the pressure to 15-0.2 mmHg at a temperature of 215-220 ° C.
The glycol removal reaction was performed for 5 hours. The collected sample had a number average molecular weight (Mn) of 16,800 and a weight average molecular weight (Mw) of 43,600. The yield of this polyester (A1) was 339 kg excluding condensed water.

To a reactor containing 339 kg of polyester (A1), 5420 g of hexamethylene diisocyanate was added, and a coupling reaction was carried out at 180 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelling occurred. Next, 1700 g of Irganox 1010 (manufactured by Ciba Geigy) as an antioxidant and 1700 g of calcium stearate as a lubricant were added, and stirring was further continued for 30 minutes. The reaction product is crushed and crushed at 90 ° C. for 6 hours.
The yield of polyester (B1) after vacuum drying is 300
kg.

The obtained polyester (B1) is a slightly ivory white wax-like crystal having a melting point of 110.
° C, the number average molecular weight (Mn) is 35,500, the weight average molecular weight (Mw) is 170,000, the MFR (190 ° C) is 1.0 g / 10 min, the viscosity of a 10% solution of orthochlorophenol is 230 poise, Temperature 190 ° C, shear rate 10
The melt viscosity at ⁰ sec ^-1 was 1.5 × 10 ⁴ poise. The average molecular weight is measured by Shodex GPC
System-11, solvent: CF ₃ COONa 5 mmol solution of hexafluoroisopropyl alcohol, concentration 0.1% by weight, calibration curve: Showa Denko KK PMMA standard sample Shodex Standard M-75
I went in.

Next, 2200 g of pure water was put into an autoclave with a stirrer having an inner volume of 5.6 L, and 28
Polyester between mesh and 35 mesh (B
2200 g of the particles of 1), 7 g of magnesium oxide, and 0.22 g of dilauryl thiodipropionate were charged. Then, while stirring, 44 g of propane and 186 g of pentane were press-fitted, the temperature was raised to 100 ° C., and the reaction was carried out for 1.5 hours. Then, the temperature in the above system was cooled to 30 ° C., and then taken out of the system to obtain polyester (B1). Expandable particles were obtained.

The obtained expandable particles were expanded 10 times by heating of steam to obtain pre-expanded particles. After drying and aging these pre-expanded particles, they were further heated and foamed with steam. When the obtained polyester (B1) is foamed 50 times, the distribution width of the bubble size is 0.08 to 0.30 m.
m, and the density was 0.024 g / cm ² as a true density.

This foam was further pulverized, and the opening of the eye was 2 m.
m was uniformly mixed into a soil having a tentative specific gravity of 1.2, and the tentative specific gravity of the mixed soil was set to 0.96. The body decomposed completely, forming cavities in the soil, and no trace of foam was observed.

Example 2 A mixture of 100 parts by weight of the polyester (B1) obtained in Example 1 and 10 parts by weight of oil cake was extruded into water using an extruder.
It was cut by a cutter to obtain pellets having a diameter of 2 mm. The pellets were uniformly mixed in the same soil as in Example 1, and a sample obtained by setting the temporary specific gravity of the mixed soil to 1.15 over time was observed. Had many cavities.

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

According to the present invention, the aliphatic polyester resin is used as a soil improving material to reduce the temporary specific gravity of the soil and to form a large number of cavities in the soil, thereby improving drainage, water retention and air permeability of the soil. It is to improve.

The aliphatic polyester resin which is the object of the present invention has excellent physical properties, such as molded articles, foams, films,
It is useful as a fiber and the like, and has microbial degradability. However, simply discarding it does not mean that it was used effectively. In the present invention, the effective use of this aliphatic polyester resin molded product waste is examined, and it is extremely effective to use the biodegradability as a soil improvement material for lightening and improving the soil. It was found.

When the present soil conditioner is used, it not only prevents soil from being cultivated, but also uses only the aliphatic polyester resin among the plastic wastes that have usually relied on landfills and incineration. It can be used as a soil improvement material.

Claims (3)

(57) [Claims] (1) Mainly, a glycol and an aliphatic dibasic acid or a derivative thereof have a number average molecular weight of 5,000 or more.
A polyester prepolymer is synthesized, and the polyester
0.1 to 5 parts by weight per 100 parts by weight of polymer
Number average molecular weight 10,000 or less using the coupling agent
A soil conditioner comprising a granular material of the above-mentioned biodegradable aliphatic polyester resin. 2. A biodegradable aliphatic polystyrene obtained by crushing a granular material such as a molded product, a foam, a sheet, a film, a yarn or the like into an opening having a mesh size of 10 mm.
Microorganisms formed from pelletized steal resin or the pulverized product
The soil improving material according to claim 1, which is a degradable aliphatic polyester resin. Wherein the above biodegradability aliphatic polyester resin, a fine biodegradable fillers or claim 1 or 2 soil conditioner according blended with mineral soil amendment material.