SOIL EROSION PREVENTER HAVING HIGH FREEZING AND THAWING STABILITY

Abstract

The present invention provides a soil erosion prevention agent which is excellent in the freeze-thaw stability while maintaining the soil erosion prevention effect. A soil erosion prevention agent of the present invention comprises a water-borne resin emulsion; and a water-soluble polymer, wherein a content of the water-borne resin emulsion is 99 to 93 mass %, a content of the water-soluble polymer is 1 to 7 mass %, and the water-borne resin emulsion contains 0.01 to 0.10 parts by mass of a structural unit derived from a polyfunctional monomer with respect to 100 parts by mass of a structural unit derived from a main monomer.

Claims

1. A soil erosion prevention agent comprising: a water-borne resin emulsion; and a water-soluble polymer, wherein a content of the water-borne resin emulsion is 99 to 93 mass %, a content of the water-soluble polymer is 1 to 7 mass %, and the water-borne resin emulsion contains 0.01 to 0.10 parts by mass of a structural unit derived from a polyfunctional monomer with respect to 100 parts by mass of a structural unit derived from a main monomer.

2. The soil erosion prevention agent of claim 1, wherein the water-borne resin emulsion contains 0.05 to 0.10 parts by mass of a structural unit derived from a polyfunctional monomer with respect to 100 parts by mass of a structural unit derived from a main monomer.

3. The soil erosion prevention agent of claim 1, wherein the water-borne resin emulsion contains a structural unit derived from vinyl acetate.

4. The soil erosion prevention agent of claim 1, comprising an ethylene-vinyl acetate copolymer emulsion.

5. A greening method using the soil erosion prevention agent of claim 1.

6. A greening method using 1 to 10 kg of the soil erosion prevention agent of claim 1 with respect to 1 m3 of the spraying material.

7. A spraying material comprising 1 to 10 kg of the soil erosion prevention agent of claim 1 with respect to 1 m3 of the spraying material.

Description

EXAMPLES

[0028] Hereinafter, Examples of the present invention will be described. Unless otherwise noted, parts and % means parts by mass and mass %, respectively.

Manufacturing Example 1

Water-Borne Resin Emulsion 1

[0029] To a high pressure polymerization tank equipped with an agitator, a solution prepared by dissolving, in 100 parts of water, 1.6 parts of DENKA POVAL B-05 (saponification degree of 88mo1%, average polymerization degree of 600, available from DENKA Company Limited), 2.7 parts of DENKA POVAL B-17 (saponification degree of 88mo1%, average polymerization degree of 1700, available from DENKA Company Limited) as an emulsifier, and 0.1 parts of formamidinesulfinic acid, 0.2 parts of sodium acetate, 0.005 parts of ferrous sulfate heptahydrate, and 0.01 parts of tetrasodium ethylenediaminetetraacetate as auxiliaries was introduced. Subsequently, 57 parts of vinyl acetate monomer, 19 parts of ethylene, and 0.06 parts of triallyl cyanurate monomer were added under agitation. After raising the internal solution temperature to 55 C., 2.7 parts of 5% t-butyl hydroperoxide aqueous solution was added continuously and polymerization was performed. During polymerization, 25 parts of vinyl acetate monomer and 0.02 part of triallyl cyanurate monomer were separately added. The polymerization was maintained until the unreacted vinyl acetate monomer reached less than 2%.

[0030] After the polymerization, the remaining ethylene was purged, and the unreacted vinyl acetate monomer contained in the emulsion obtained was removed under reduced pressure. Accordingly, the water-borne resin emulsion 1 which contains 0.10 parts by mass of a polyfunctional monomer with respect to a main monomer, as shown in table 1.

Manufacturing Examples 2 to 6

Water-Borne Resin Emulsions 2 to 6

[0031] The water-borne resin emulsions 2 to 6 were manufactured with conditions corresponding to the conditions of Manufacturing Example 1, according to Table 1. The water-borne resin emulsion 2 which contains 0.05 parts by mass of the polyfunctional monomer with respect to the main monomer was obtained. The water-borne resin emulsion 3 which contains 0.01 parts by mass of the polyfunctional monomer with respect to the main monomer was obtained. The water-borne resin emulsion 4 which contains none of the polyfunctional monomer was obtained. The water-borne resin emulsion 5 which contains 0.20 parts by mass of the polyfunctional monomer with respect to the main monomer was obtained. The water-borne resin emulsion 6 which contains 0.10 parts by mass of the polyfunctional monomer with respect to the main monomer was obtained.

(Preparation of Soil Erosion Prevention Agent: Example 1)

[0032] PEG400 (available from Junsei Chemical Co., Ltd.) as the water-soluble polymer was added to the water-borne resin emulsion 1 obtained in Manufacturing Example 1 so that the soil erosion prevention agent has a predetermined content (mass %) shown in Table 2, and water (pure water) was also added so that the solid content of the soil erosion prevention agent is 30 mass %. Then, the soil erosion prevention agent of Example 1 was obtained. In each example of Table 2, * means that the water-soluble polymer described in the same row was used.

(Preparation of Soil Erosion Prevention Agents: Examples 2 to 14 and Comparative Examples 1 to 3)

[0033] The soil erosion prevention agents of Examples 2 to 14 and Comparative Examples 1 to 3 were prepared according to the composition and the solid content described in Table 2. As the water-soluble polymers, PEG 400 (available from Junsei Chemical Co., Ltd.), PEG 20000 (available from Junsei Chemical Co., Ltd.), Denka Poval B-05 (saponification degree 88 mol %, average degree of polymerization 600, available from DENKA Company Limited), Denka Poval B-17 (saponification degree 88 mol %, average degree of polymerization 1700, available from DENKA Company Limited), Denka Poval B-33 (saponification degree 88 mol %, average polymerization degree 3,300, available from DENKA Company Limited), hydroxyethyl cellulose (2% aqueous solution viscosity (20 C.): 200-300 mPa.Math.s, available from Tokyo Chemical Industry Co., Ltd.), carboxymethyl cellulose cellogen 7A (available from DKS Co., Ltd.) were respectively used.

[0034] For each soil erosion prevention agent, freeze-thaw stability and soil erosion prevention performance were evaluated, and the results are shown in Table 2. The freeze-thaw stability and the soil erosion prevention performance were shown as F and E, respectively.

(Measurement of Toluene Insoluble Matter)

[0035] (1) 10 g of emulsion is coated on a fluororesin plate (area of about 100 cm.sup.2) and dried at 23 C. for 5 days to obtain a dry film. [0036] (2) 1 g of the dry film finely cut into 5 mm square is put into a screw tube, the screw tube is filled with 50 g of toluene and sealed tightly. [0037] (3) The screw tube is shaken for 5 hours in a 50 C. hot water bath. [0038] (4) The resulted toluene solution is filtered through 200 mesh wire net, the insoluble matter separated (and recovered) is dried in a draft at 23 C. overnight, and then dried in a dryer (105 C.) for 3 hours, and the dry weight of the insoluble matter recovered is measured. [0039] (5) The toluene insoluble matter is calculated by a following equation.

Toluene insoluble matter (%)=100 (weight of the insoluble matter recovered)/(weight of charged film)

(Evaluation of Freeze-Thaw Stability)

[0040] (1) 50 g of the emulsion is taken in a 100 ml container. [0041] (2) The container is left for 16 hours in an environmental testing machine (20 C.) and frozen. [0042] (3) The container is taken out of the environmental testing machine and left in a hot water bath at 30 C. for 1 hour to be melted. [0043] (4) The state after melting is visually observed and the extent of aggregation is evaluated according to the following criteria. [0044] a: equivalent to emulsion before freezing [0045] b: Fluid flowing, but aggregates are observed [0046] c: It becomes a sponge and does not flow

(Evaluation of Soil Erosion Prevention Effect)

[0047] Next, a vegetation base made by a thick layer base material spraying method formulated with the prepared sample was constructed, and the amount of soil that flow by the rainfall test was measured. [0048] (1) Blending: Into a container, 7L of bark compost (available from Fujimi-ryokka co. jp, Fujimi-soil No. 5), 21 g of high analysis compound fertilizer (available from Nittofc Co., Ltd., 15-15-15), 3.5 g of seeds (available from KANEKO SEEDS CO., LTD., Italian ryegrass), and 21 g of the soil erosion prevention agent were added, and the mixture was kneaded to prepare a vegetation base material. [0049] (2) Construction: The vegetation base material was filled into a wooden frame (30 cm30 cm rectangle, height 10 cm) and was smoothed. Then, the vegetation base material was pressured to half the volume from the upper side. [0050] (3) Maturing: The wooden frame was removed, and the vegetation base material was allowed to mature overnight in a room kept at 23 C. [0051] (4) Rainfall : Water was applied to the matured vegetation base using a watering can. The vegetation base was inclined by 9, and water was applied from a height of 50 cm with an intensity of 200 mm per 1 hour for 30 minutes. The amount of the soil flown was visually observed and evaluated as follows. [0052] a: Soil flown is almost not observed. [0053] b: Soil flown is partially observed. [0054] c: Soil flown is observed all over.

[0055] According to Table 2, it has been demonstrated that the freeze-thaw stability of the soil erosion prevention agent improves as the content of water-soluble polymer increases, and the effect of preventing soil erosion tends to decrease. It has also been demonstrated that with the same content of the water-soluble polymer, the freeze-thaw stability of the soil erosion prevention agent is improved, as the content of the polyfunctional monomer contained in the water-borne resin emulsion is higher, even when the content of the water-soluble polymer is small.

[0056] Accordingly, it has been demonstrated that by using as the soil erosion prevention agent comprising: a water-borne resin emulsion; and a water-soluble polymer, wherein a content of the water-soluble polymer is 1 to 7 mass %, and the water-borne resin emulsion contains 0.01 to 0.10 parts by mass of a structural unit derived from a polyfunctional monomer with respect to 100 parts by mass of a structural unit derived from a main monomer., the freeze-thaw stability can be improved while maintaining the soil erosion prevention effect.

TABLE-US-00001 TABLE 1 Water-Borne Resin Emulsion 1 2 3 4 5 6 The number of polyfunctional monomer to main monomer 0.10 0.05 0.01 0 0.20 0.10 (parts by mass) Initial Pure water 100 100 100 100 100 100 preparation DENKA POVAL B-05 1.6 1.6 1.6 1.6 1.6 1.6 DENKA POVAL B-17 2.7 2.7 2.7 2.7 2.7 2.7 Formamidinesulfinic acid 0.1 0.1 0.1 0.1 0.1 0.1 Sodium acetate 0.2 0.2 0.2 0.2 0.2 0.2 Ferrous sulfate heptahydrate 0.005 0.005 0.005 0.005 0.005 0.005 Tetrasodium ethylenediaminetetraacetate 0.01 0.01 0.01 0.01 0.01 0.01 Vinyl acetate monomer 57 57 57 57 57 57 Ethylene monomer 19 19 19 19 19 19 Triallyl cyanurate monomer 0.06 0.03 0.006 0 0.12 Triallyl isocyanurate monomer 0.06 Separately Vinyl acetate monomer 25 25 25 25 25 25 added Triallyl cyanurate monomer 0.02 0.01 0.002 0 0.04 monomer Triallyl isocyanurate monomer 0.02 Separately 5 mass % t-butyl hydroperoxide aqueous solution 2.7 2.7 2.7 2.7 2.7 2.7 added additive

TABLE-US-00002 TABLE 2 Example 1 2 3 4 5 6 7 8 9 Emulsion Water-Borne Resin Emulsion No. 1 1 1 1 1 1 1 1 1 Multifunctional monomer (part) 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 Water PEG400 * soluble PEG20000 * polymer DENKA POVAL B-05 * DENKA POVAL B-17 * DENKA POVAL B-33 * DENKA POVAL B-05+ B-17(1:1) * DENKA POVAL B-17+ B-33(1:1) * Hydroxyethyl cellulose * Carboxymethyl cellulose * Evaluation item F E F E F E F E F E F E F E F E F E Measurement Water-soluble polymer 0 c a c a c a c a c a c a c a c a c a content 1 a a a a a a a a a a a a a a a a a a (mass %) 2 a a a a a a a a a a a a a a a a a a 3 a a a a a a a a a a a a a a a a a a 4 a a a a a a a a a a a a a a a a a a 5 a a a a a a a a a a a a a a a a a a 7 a b a b a b a b a b a b a b a b a b 10 a c a c a c a c a c a c a c a c a c Example Comparative Example 10 11 12 13 14 1 2 3 Emulsion Water-Borne Resin Emulsion No. 2 3 3 3 6 4 4 5 Multifunctional monomer (part) 0.05 0.01 0.01 0.01 0.10 0 0 0.20 Water PEG400 * * * * * soluble PEG20000 polymer DENKA POVAL B-05 DENKA POVAL B-17 * * DENKA POVAL B-33 DENKA POVAL B-05+ B-17(1:1) DENKA POVAL B-17+ B-33(1:1) Hydroxyethyl cellulose * Carboxymethyl cellulose Evaluation item F E F E F E F E F E F E F E F E Measurement Water-soluble polymer 0 c a c a c a c a c a c a c a c b content 1 a a b a b a b a a a c a c a a b (mass %) 2 a a a a a a a a a a c a c a a b 3 a a a a a a a a a a c a c a a b 4 a a a a a a a a a a c a c a a b 5 a a a a a a a a a a c a c a a b 7 a b a b a b a b a b a b a b a b 10 a c a c a c a c a c a c a c a c

INDUSTRIAL APPLICABILITY

[0057] Since the soil erosion prevention agent including the water-borne resin emulsion of the present invention improves the freeze-thaw stability while maintaining the soil erosion prevention effect, it is excellent in storage stability in the winter in a cold district. Accordingly, the soil erosion prevention agent of the present invention can be used for a greening construction and the like.