JP2005126285A - Composting assistant and method for gelation or solidification of raw compost material by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composting assistant which has biodegradability and a high water absorptivity and effects the gelation or solidification of a raw compost material to promote its composting when applied thereto. <P>SOLUTION: The composting assistant used comprises a polyvinyl alcohol comprising repeating units represented by formula (I) or a crosslinked product thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a composting aid and a method for gelling or solidifying compost raw materials using the same. More specifically, a composting aid comprising a polyvinyl alcohol copolymer or a cross-linked product thereof, and the composting aid are applied to compost raw materials such as animal manure and garbage to effectively gel the compost raw materials. It relates to a method of solidifying or solidifying.

In composting (composting) such as livestock manure, a water conditioner is indispensable in order to promote fermentation by microorganisms. In other words, composting is the production of compost, which is an organic fertilizer, by decomposing and changing organic matter in manure of animals such as humans, cattle, horses, pigs, and chickens. It is a temperate microorganism. The water content is optimally 60 to 70% by weight. If the water content is higher than this range, the air permeability is poor and the fermentation is inhibited, and the fermentation is similarly deteriorated even if the water content is low.
Currently, sawdust, rice straw, bark, and the like are used as moisture regulators for this purpose, but their water absorption is about 1 to 5 times the mass, resulting in a low water absorption rate. The amount of compost increases due to the large amount of use of the moisture adjusting agent, making it difficult to process in the region. As a result, there are problems such as an increase in equipment size and an increase in processing costs.

Moreover, since there are many usages of sawdust, rice straw, etc., there existed problems, such as composting taking time and being difficult to complete ripe compost. High-moisture compost materials are very difficult to handle, and when transported by a belt conveyor or transported by a dump truck, the high-moisture compost materials spread in a slurry state, causing the surrounding pollution due to runoff or scattering, or improving transport efficiency. There was a problem of decline.
Moreover, it is well-known about using a polymer crosslinked body for a composting process (for example, refer patent documents 1-6). However, it cannot be said that these known crosslinked polymers can sufficiently solve the above problems as a composting aid.

JP-A-56-114889 JP 57-81893 A JP 58-208189 A JP 62-202889 A JP-A-6-205624 JP-A-8-208362

  The present invention solves such problems of the prior art, has a high water absorption ratio, biodegrades in a short time and does not require a long time for composting, and allows downsizing of the treatment facility. Composting aid that exhibits excellent effects such as no environmental pollution due to spillage and scattering, and improved transport efficiency, and by applying a small amount of this composting aid to the composting material, the composting material is gelled. Or it aims at providing the method of solidifying.

As a result of intensive research to develop a composting aid that exhibits the above-described excellent effects, the present inventors have found that a polyvinyl alcohol copolymer having a specific repeating unit or a cross-linked product thereof is a composting aid. As an agent, it has been found that it can be adapted to its purpose.
That is, the present invention provides a method for gelling or solidifying the following composting aid and compost raw material.
1. A composting aid comprising a polyvinyl alcohol copolymer containing a repeating unit represented by formula (I) or a crosslinked body thereof.

[Wherein, R ¹ is a hydrogen atom, a methyl group or CH ₂ COOX, R ² and R ³ are each independently a hydrogen atom or an alkyl group having 4 or less carbon atoms, R ⁴ is COOX, SO ₃ X, NH ₂ , NHCN ₃ , N (CH ₃ ) ₂ or CONR ⁵ R ⁶ , Y represents a hydrogen atom or COOX (X represents a hydrogen atom, an alkyl group having 4 or less carbon atoms, an alkali metal or an ammonium group, and R ⁵ and R ⁶ represent Each independently represents a hydrogen atom or an alkyl group having 4 or less carbon atoms.), N is an integer of 0-5. ]
2. The composting aid according to 1 above, wherein the content of the repeating unit represented by the general formula (I) in the polyvinyl alcohol copolymer before crosslinking is 0.1 to 30 mol%.
3. The composting aid according to 1 or 2 above, comprising a crosslinked polyvinyl alcohol copolymer having a crosslinked structure represented by the general formula (II) and / or the general formula (III).

[Wherein R ⁷ represents a hydrogen atom, a methyl group or an ethyl group. ]
4). A method for gelling or solidifying a compost raw material, wherein the compost raw material is applied with any one of the above-mentioned composting aids to absorb moisture contained in the compost raw material and lose fluidity. .
5). 4. The method for gelation or solidification of a compost material as described in 4 above, wherein the compost material is animal manure, garbage or a mixture thereof.
6). The method for gelation or solidification of a composting material according to 4 or 5 above, wherein the composting aid is applied at a ratio of 0.01 to 30% by mass with respect to the composting material.

  The composting aid comprising the polyvinyl alcohol copolymer of the present invention or a cross-linked product thereof has biodegradability and high water absorption, and the composting raw material is applied to the compost raw material by applying the composting aid of the present invention to the compost raw material. Gelling or solidifying the material, it does not require a long time for composting, biodegrades in a short time, enables downsizing of the treatment facility, and exhibits excellent effects such as improving the transportation efficiency.

The composting aid of the present invention comprises a polyvinyl alcohol copolymer containing a repeating unit represented by the general formula (I) or a cross-linked product thereof.
This crosslinked polyvinyl alcohol copolymer is obtained by, for example, polymerizing a copolymer monomer having the structure of the following general formula (IV) and a vinyl compound such as vinyl acetate in the presence of a radical initiator, It can be produced by producing a coalescence, saponifying it to obtain a polyvinyl alcohol copolymer, and subjecting it to a crosslinking reaction as necessary.

The symbols in the formula are the same as in general formula (I), R ¹ is a hydrogen atom, methyl group or CH ₂ COOX, R ² and R ³ are each independently a hydrogen atom or an alkyl group having 4 or less carbon atoms, R ⁴ is COOX, SO ₃ X, NH ₂ , NHCN ₃ , N (CH ₃ ) ₂ or CONR ⁵ R ⁶ , Y represents a hydrogen atom or COOX (X is a hydrogen atom, an alkyl group having 4 or less carbon atoms, an alkali metal or ammonium) R ⁵ and R ⁶ each independently represents a hydrogen atom or an alkyl group Me having 4 or less carbon atoms.), N is an integer of 0 to 5.
Examples of the hydrocarbon group having 4 or less carbon atoms of R ² , R ³ , R ⁵ , R ⁶ and X include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec -A butyl group, a tert- butyl group, etc. are mentioned. Examples of the alkali metal of X include lithium, sodium, potassium and the like.

Specific examples of the copolymerization monomer having the structure of the general formula (IV) include (meth) acrylates such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, acrylamide, methacrylamide, N, N-dimethylacrylamide. Vinyl sulfonic acid, allyl sulfonic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, 2-acrylamido-2-methylpropene sulfonic acid and the like. These copolymerization monomers can be used alone or in combination of two or more.
As the radical initiator, any of initiators used in ordinary radical polymerization may be used. Ammonium persulfate, potassium persulfate, benzoyl peroxide, azobisisobutyronitrile, 2,2′-azobis (2-amidino) Propane) dihydrochloride and the like.

For example, methanol, ethanol, methyl acetate or the like is used as a solvent for producing a vinyl acetate copolymer, and the amount of radical initiator used is usually 0.001 to 10 mol%, preferably based on the total amount of monomers. 0.005 to 5 mol%. The saponification of the vinyl acetate copolymer is carried out by adding an alkali to the vinyl acetate copolymer solution and hydrolyzing it. The alkali to be used is not particularly limited, but sodium hydroxide, sodium methoxide and the like are preferably used.
In the polyvinyl alcohol copolymer thus obtained, the repeating unit represented by the general formula (I) is a proportion of 0.1 to 30 mol% from the viewpoint of the performance of the obtained composting aid. It is preferable that it is contained in the ratio of 0.2-10 mol%.

The composting aid of the present invention can be used as an uncrosslinked product or a crosslinked product. When the ratio of the general formula (I) is small, crosslinking is performed by a hydrogen bond between OH groups and a gel state is obtained.
In the case of a crosslinked body, those having a crosslinked structure represented by the following general formula (II) and / or general formula (III) are preferably used.

[Wherein R ⁷ represents a hydrogen atom, a methyl group or an ethyl group. ]
As the crosslinking agent, a compound having two or more functional groups capable of reacting with a carboxyl group in one molecule is used. For example, polyvalent amines such as 1,4-diaminobutane, ethylene glycol diglycidyl ether, glycerol Triglycidyl ether, polyethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, diethanolamine, triethanolamine, polyoxypropylene, polyvinyl alcohol, pentaerythritol, Sorbit, sorbitan, glucose, mannitol, mannitan and the like are preferably used. These may be used singly or in combination of two or more.
The proportion of the crosslinking agent used is usually 0.001 to 10% by mass, preferably 0.01 to 5% by mass, based on the total amount of raw materials used here. When the use ratio of the crosslinking agent is within the above range, the obtained polyvinyl alcohol copolymer crosslinked product has a sufficient degree of crosslinking and also has good water absorption.

  The drying treatment of the polyvinyl alcohol copolymer or its cross-linked product is preferably carried out at a temperature of 200 ° C. or lower, and a freeze-drying method can also be adopted. In the case of granulation, there is no particular limitation on the granulation method. Depending on the purpose of use, for example, a crushing granulation method, an extrusion granulation method, or a method of crushing in a hydrogel state, a conventionally known method can be used. Can be appropriately selected.

Thus, the composting aid of the present invention comprising a polyvinyl alcohol copolymer or a cross-linked product thereof can be obtained efficiently. Although the obtained composting aid has water absorption performance as it is, the water absorption performance is improved by adding alkali (NaOH, KOH, ammonia, etc.) so that the pH when containing water is 6-9.
The composting aid of the present invention is advantageous when the water absorption ratio is in the range of 5-1000, preferably 10-100. Here, the water absorption ratio is a value when a 0.9 mass% sodium chloride aqueous solution is used.

  When the composting aid of the present invention is used, two or more kinds of cross-linked bodies such as polyamino acid-based cross-linked bodies, cross-linked bodies of other polysaccharides, cross-linked bodies having biodegradability of other chemical synthesis systems, etc. May be used in combination. Moreover, you may mix | blend (mix) these crosslinked bodies in the composting adjuvant of this invention. The composting aid of the present invention can be used in combination with sawdust, rice straw, rice chaff, bark and the like.

In the method for gelation or solidification of the compost raw material of the present invention, by applying the aforementioned composting aid of the present invention to the compost raw material, the water contained in the compost raw material is absorbed and the fluidity is lost. The composting material is gelled or solidified.
Animal compost, garbage, or a mixture thereof can be used as a compost raw material. Examples of animal manure include manure, cattle, horses, pigs, chickens, etc., and examples of raw garbage include waste vegetables, vegetable scraps, leftover food, relatively high moisture food residues, beverage residue Etc.
The amount of the composting aid to be applied for gelling or solidifying the compost raw material is usually 0.01 to 30% by weight, preferably 0.1 to 10% by weight, based on the compost raw material. .

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, the water absorption capacity | capacitance of the composting adjuvant was calculated | required according to the method shown below using 0.9 mass% sodium chloride aqueous solution.
1.00 g of composting aid was immersed in 300 ml of 0.9 mass% sodium chloride aqueous solution and left at room temperature for 3 hours. The swollen composting aid was separated using a sieve having a pore size of 75 μm, and the weight of the composting aid was measured. The water absorption magnification was calculated from the following equation.
Water absorption ratio =
Weight of composting aid after swelling (g) / Weight of composting aid before swelling (g)

Example 1
(polymerization)
A 500 ml separable flask equipped with a stirrer, a thermocouple and a reflux condenser was charged with 8.60 g of methyl acrylate, 77.48 g of vinyl acetate and 250 ml of methanol, and immersed in an oil bath at 70 ° C. When the temperature inside the flask became constant, 0.82 g of azobisisobutyronitrile was added to initiate polymerization. When polymerization was carried out for 4 hours, the reaction was stopped, and methanol as a solvent was distilled off. Then, it melt | dissolved in acetone again and reprecipitation refinement | purification was performed in hexane. Further, drying under reduced pressure was performed to obtain a polymer (methyl acrylate / vinyl acetate copolymer) (yield 73.18 g). ^The composition calculated from ¹ H-NMR was a methyl acrylate: vinyl acetate molar ratio = 10: 90.
(Saponification reaction)
In a 1000 ml eggplant flask, 50.0 g of the polymer was dissolved in 400 ml of methanol, and 27.88 g of NaOH and 100 ml of water were added. After refluxing for 6 hours, methanol was distilled off, 400 ml of water was added, the pH was adjusted to 12, and refluxing was performed again for 8 hours. After concentrating the reaction solution, it was added dropwise to an acetone / water mass ratio = 80/20 solution for reprecipitation purification, and the resulting aqueous solution was adjusted to pH 7 and lyophilized to obtain a solid polyvinyl alcohol copolymer. (Yield 26.00 g). Its weight average molecular weight was 250,000.
(Crosslinking reaction)
20.0 g of the polyvinyl alcohol copolymer obtained by the saponification reaction and 100 mg of ethylene glycol diglycidyl ether were dissolved in 80 ml of water and immersed in an oil bath at 80 ° C. for 12 hours to carry out a crosslinking reaction. After completion of the reaction, the obtained cross-linked product was pulverized and dried with a dryer set at 50 ° C. The water absorption of the dried crosslinked product was 17 times.

Example 2
A 500 ml separable flask equipped with a stirrer, a thermocouple and a reflux condenser was charged with 7.10 g of acrylamide, 77.48 g of vinyl acetate and 250 ml of methanol, and immersed in an oil bath at 70 ° C. When the temperature inside the flask became constant, 0.82 g of azobisisobutyronitrile was added to initiate polymerization. When polymerization was carried out for 4 hours, the reaction was stopped, and methanol as a solvent was distilled off. Then, it melt | dissolved in acetone again and reprecipitation refinement | purification was performed in hexane. Further, drying was performed under reduced pressure to obtain a polymer (acrylamide / vinyl acetate copolymer) (yield: 76.81 g). ^The composition calculated from ¹ H-NMR was acrylamide: vinyl acetate molar ratio = 12: 88.
The obtained polymer 50.0 was saponified in the same manner as in Example 1. The yield of the polyvinyl alcohol copolymer was 26.50 g, and the weight average molecular weight was 270,000. Next, a crosslinking reaction was carried out in the same manner as in Example 1 using 20.0 g of this polyvinyl alcohol copolymer. The water absorption of the dried crosslinked product was 18 times.

Example 3
Using the cross-linked product obtained in the same manner as in Example 1, a fermentation experiment of livestock excreta was conducted.
That is, 200 g of the crosslinked product obtained in the same manner as in Example 1 and 5.0 kg of beef dung slurry were mixed, packed in a cylindrical tube having a diameter of 25 cm and a height of 50 cm, and aerated from below.
This cylindrical tube was placed at room temperature (25 ° C.), and the internal temperature and the change over time in the exhausted CO ₂ concentration were measured. The results are shown in Table 1. The state of the slurry before fermentation was crisp and air permeability was good.

Example 4
Using the cross-linked product obtained in the same manner as in Example 2, a fermentation experiment for livestock excrement was conducted in the same manner as in Example 3. Table 1 shows the internal temperature of the cylindrical tube and the change over time in the CO ₂ concentration discharged. The state of the slurry before fermentation was crisp and air permeability was good.

Example 5
A livestock excrement fermentation experiment was conducted in the same manner as in Example 3 using 300 g of a poly (vinyl alcohol-vinyl acetate-itaconic acid) copolymer (manufactured by Aldrich). Table 1 shows the internal temperature of the cylindrical tube and the change over time in the CO ₂ concentration discharged. The state of the slurry before fermentation was crisp and air permeability was good.

Comparative Example 1
In Example 1, only the cow dung slurry was packed in a cylindrical tube without mixing the composting aid (cross-linked product), and aerated from the bottom. Table 1 shows changes with time of the internal temperature of the cylindrical tube and the CO ₂ concentration discharged. The state of the cow dung slurry before fermentation was sticky and the air permeability was poor.

Claims (6)

A composting aid comprising a polyvinyl alcohol copolymer containing a repeating unit represented by formula (I) or a crosslinked product thereof.

[Wherein, R ¹ is a hydrogen atom, a methyl group or CH ₂ COOX, R ² and R ³ are each independently a hydrogen atom or an alkyl group having 4 or less carbon atoms, R ⁴ is COOX, SO ₃ X, NH ₂ , NHCN ₃ , N (CH ₃ ) ₂ or CONR ⁵ R ⁶ , Y represents a hydrogen atom or COOX (X represents a hydrogen atom, an alkyl group having 4 or less carbon atoms, an alkali metal or an ammonium group, and R ⁵ and R ⁶ represent Each independently represents a hydrogen atom or an alkyl group having 4 or less carbon atoms.), N is an integer of 0-5. ]   The composting aid according to claim 1, wherein the content of the repeating unit represented by the general formula (I) in the polyvinyl alcohol copolymer before crosslinking is 0.1 to 30 mol%. The composting aid according to claim 1 or 2, comprising a crosslinked polyvinyl alcohol copolymer having a crosslinked structure represented by the general formula (II) and / or the general formula (III).

[Wherein R ⁷ represents a hydrogen atom, a methyl group or an ethyl group. ] Gelling of a compost raw material characterized in that by applying the composting aid according to any one of claims 1 to 3 to the compost raw material, moisture contained in the compost raw material is absorbed and fluidity is lost. Or solidification method. The method for gelation or solidification of a compost raw material according to claim 4, wherein the compost raw material is animal manure, garbage, or a mixture thereof. The method for gelation or solidification of a compost raw material according to claim 4 or 5, wherein the composting aid is applied at a ratio of 0.01 to 30% by mass with respect to the compost raw material.