Herbicide composition

The present invention relates to a herbicide composition comprising (a) paraquat and/or diquat, (b) an anionic surfactant and (c) a chelating agent, wherein a molar ratio (c)/(a) of the component (c) to the component (a) is 0.1-3. The herbicidal effect is markedly enhanced by the incorporation of the chelating agent.

This application is A 371 of PCT/JP94/01953 filed Nov. 18, 1994. 
1. Technical Field 
The present invention relates to a herbicide composition, and particularly 
to a herbicide composition enhanced in its herbicidal effect. 
2. Background Art 
Paraquat (1,1'-dimethyl-4,4'-bipyridinium dichloride) and diquat 
(1,1'-ethylene-2,2'-bipyridinium dibromide) are bipyridinium type contact 
herbicides, have no selectivity and exhibit strong weed-killing power by a 
foliage treatment. Therefore, they are widely used. In herbicide 
compositions containing these compounds, in which their herbicidal 
components are diluted with water before their sprinkling, an anionic 
surfactant is incorporated for the purpose of evenly applying such a 
liquid chemical to the surfaces of stems and leaves of a target plant and 
causing the liquid chemical applied to remain for a long period of time on 
the stems and leaves so as to penetrate into the plant body (Japanese 
Patent Application Laid-Open No. 230608/1992). 
However, the herbicidal effects of these compositions containing the 
bipyridinium type herbicide and the anionic surfactant have not been fully 
satisfactory. On the contrary, the herbicidal effects have been lowered 
according to the kind of an anionic surfactant to be used. The cause of 
this reduction in activity is considered to be attributed to the fact that 
the bipyridinium type herbicide forms a complex with the anionic 
surfactant. 
The above-described bipyridinium type herbicides have also involved a 
problem that the amount of the herbicide to be used is limited due to 
their high toxicity. 
Accordingly, it is an object of the present invention to provide a 
composition in which the herbicidal effect of a bipyridinium type 
herbicide is enhanced. 
DISCLOSURE OF THE INVENTION 
In view of the foregoing circumstances, the present inventors have added 
various components to a combined system containing a bipyridinium type 
herbicide and an anionic surfactant to carry out an investigation as to 
the effects of such components for enhancing the herbicidal activity. As a 
result, it has been found that when a chelating agent is added in a 
proportion of 0.1-3 moles per mole of the pyridinium type herbicide, the 
herbicidal activity is markedly enhanced, thus leading to completion of 
the present invention. 
According to the present invention, there is thus provided a herbicide 
composition comprising the following components (a), (b) and (c): 
(a) paraquat and/or diquat; 
(b) an anionic surfactant; and 
(c) a chelating agent, 
wherein a molar ratio (c)/(a) of the component (c) to the component (a) is 
0.1-3. 
BEST MODE FOR CARRYING OUT THE INVENTION 
The component (a) in the present invention is an active component for 
weeding. Paraquat and diquat can be used either singly or in combination. 
No particular limitation is imposed on the amount of the component (a) to 
be incorporated into the composition so far as it is sufficient to attain 
satisfactory herbicidal activity. It is also permissible to prepare a 
composition containing the component (a) at a high concentration in 
advance and dilute the composition at the time of use. Specifically, the 
component (a) is incorporated so as to give a concentration of preferably 
0.1-50 wt. % (hereinafter indicated merely by "%"), more preferably 
0.1-20%, particularly preferably 0.5-15% of the total weight of the 
composition. At the time the herbicide composition is used, it is 
preferably diluted for use in such a manner that the concentration of the 
component (a) amounts to 0.005-0.8%, particularly 0.005-0.5%. 
Examples of the anionic surfactant of the component (b) include salts of 
higher fatty acids, alkyl(or alkenyl)sulfates, polyoxyalkylene alkyl(or 
alkenyl)ether sulfates, polyoxyalkylene alkyl(or alkenyl)aryl ether 
sulfates, polyoxyalkylene styrylphenyl ether sulfates, mono- or 
di-alkyl(or alkenyl)benzenesulfonates, alkyl(or 
alkenyl)naphthalenesulfonates, condensates of an alkyl(or 
alkenyl)naphthalenesulfonate with formaldehyde, alkyl(or alkenyl)diphenyl 
ether sulfonates, alkyl(or alkenyl)sulfonates, alkyl(or 
alkenyl)sulfosuccinates, mono- or di-alkyl(or alkenyl)phosphates, 
polyoxyalkylene mono- or di-alkyl (or alkenyl)ether phosphates, 
polyoxyalkylene mono- or di-phenyl ether phosphates, polyoxyalkylene mono- 
or di-alkyl(or alkenyl)phenyl ether phosphates, salts of polycarboxylic 
acids, alkyl(or alkenyl)polyoxyalkylene ether acetates and N-methyl-fatty 
acid taurides. Of these, the alkyl(or alkenyl)sulfates, polyoxyalkylene 
alkyl(or alkenyl)ether sulfates, polyoxyalkylene alkyl(or alkenyl)aryl 
ether sulfates, alkyl(or alkenyl)naphthalenesulfonates, mono- or 
di-alkyl(or alkenyl)benzenesulfonates, polyoxyalkylene mono- or 
di-alkyl(or alkenyl)ether phosphates, polyoxyalkylene mono- or di-phenyl 
ether phosphates, polyoxyalkylene mono- or di-alkyl(or alkenyl)phenyl 
ether phosphates, salts of polycarboxylic acids, salts of saturated or 
unsaturated higher fatty acids and alkyl(or alkenyl)polyoxyalkylene ether 
acetates are more preferred. Of these, the alkyl(or alkenyl)sulfates, 
polyoxyalkylene alkyl(or alkenyl)ether sulfates, polyoxyalkylene alkyl(or 
alkenyl)ether acetates, polyoxyalkylene mono- or di-alkyl(or alkenyl)ether 
phosphates, salts of saturated or unsaturated higher fatty acids, alkyl(or 
alkenyl)benzenesulfonates and alkyl(or alkenyl)naphthalenesulfonates are 
particularly preferred. Among others, the polyoxyalkylene alkyl(or 
alkenyl)ether acetates and polyoxyalkylene mono- or di-alkyl(or 
alkenyl)ether phosphates are most preferred. 
Preferred alkyl or alkenyl groups or fatty acid residues of these anionic 
surfactants are those having 4-26 carbon atoms with those having 8-26 
carbon atoms being more preferred. These alkyl or alkenyl groups or fatty 
acid residues may be either linear or branched. The polyoxyalkylene groups 
in the above anionic surfactants include polyoxyethylene, polyoxypropylene 
and polyoxybutylene groups with the polyoxyethylene group being 
particularly preferred. The number of moles of the polyoxyalkylene group 
to be added is preferably 1-20, particularly 1-10. Examples of salts of 
the anionic surfactants include salts with an alkali metal such as sodium 
or potassium, salts with an alkaline earth metal such as calcium or 
magnesium, ammonium salts, and salts with an alkanolamine such as mono-, 
di- or tri-ethanolamine. 
Specific preferable examples of the anionic surfactants include C.sub.8-24 
-alkylsulfates, polyoxyethylene (EO=1-10) C.sub.8-24 -alkyl ether 
sulfates, polyoxyethylene (EO=1-10) C.sub.8-24 -alkylphenyl ether 
sulfates, C.sub.8-24 -alkylbenzenesulfonates, C.sub.4-24 
-alkylnaphthalenesulfonates, polyoxyethylene (EO=1-10) mono- or 
di-C.sub.8-24 -alkyl ether phosphates, salts of saturated or unsaturated 
C.sub.8-24 -fatty acids and C.sub.8-24 -alkyl(or alkenyl)polyoxyethylene 
(EO=1-20)ether acetates. 
The amount of these anionic surfactants (b) to be incorporated into the 
herbicide composition according to the present invention is preferably 
within a range of 0.1-20, particularly 0.3-10 in terms of a weight ratio 
(b)/(a) of the component (b) to the component (a). 
No particular limitation is imposed on the chelating agent (c) useful in 
the practice of the present invention so far as it has the ability to 
chelate an metal ion. Examples of the chelating agent (c) used in the 
present invention include aminopolycarboxylic acid type chelating agents, 
aromatic or aliphatic carboxylic acid type chelating agents, amino acid 
type chelating agents, ether polycarboxylic acid type chelating agents, 
phosphonic acid type chelating agents, hydroxycarboxylic acid type 
chelating agents, polyelectrolyte type chelating agents (including 
oligomers) and dimethylglyoxime (DG). These chelating agents may be in the 
form of either an acid or a salt such as the sodium, potassium or ammonium 
salt. 
Specific examples of the aminopolycarboxylic acid type chelating agents 
include: 
a) compounds represented by a chemical formula R.sup.1 NX.sub.2 ; 
b) compounds represented by a chemical formula NX.sub.3 ; 
c) compounds represented by a chemical formula R.sup.1 --NX--CH.sub.2 
CH.sub.2 --NX--R.sup.1 ; 
d) compounds represented by a chemical formula R.sup.1 --NX--CH.sub.2 
CH.sub.2 --NX.sub.2 ; 
e) compounds represented by a chemical formula X.sub.2 N--R.sup.2 
--NX.sub.2 ; and 
f) compounds similar to the compounds e), which contain 4 or more Xs, for 
example, a compound represented by a formula 
##STR1## 
In the above formulae, X denotes --CH.sub.2 COOH or --CH.sub.2 CH.sub.2 
COOH, R.sup.1 means one of groups contained in known chelating agents of 
this kind, such as a hydrogen atom, alkyl groups, a hydroxyl group and 
hydroxyalkyl groups, and R.sup.2 represents one of groups contained in 
known chelating agents of this kind, such as alkylene groups and 
cycloalkylene groups. 
Representative examples of the aminopolycarboxylic acid type chelating 
agents include ethylenediaminetetraacetic acid (EDTA), 
cyclohexanediaminetetraacetic acid (CDTA), nitrilotriacetic acid (NTA), 
iminodiacetic acid (IDA), N-(2-hydroxyethyl)iminodiacetic acid (HIMDA), 
diethylenetriaminepentaacetic acid (DTPA), 
N-(2-hydroxyethyl)ethylenediaminetriacetic acid (EDTA-OH) and glycol ether 
diaminetetraacetic acid (GEDTA), and besides salts (for example, the 
sodium salts and potassium salts) thereof. 
Examples of the aromatic or aliphatic carboxylic acid type chelating agents 
include oxalic acid, succinic acid, pyruvic acid and anthranilic acid, and 
besides salts (for example, the sodium salts and potassium salts) thereof. 
Examples of the amino acid type chelating agents used in the present 
invention include glycine, serine, alanine, lysine, cystine, cysteine, 
ethionine, tyrosine, methionine, and salts (for example, the sodium salts 
and potassium salts) and derivatives thereof. 
Examples of the ether polycarboxylic acid type chelating agents include 
compounds represented by the following formula (1), analogous compounds to 
the compounds represented by the following formula and salts (for example, 
the sodium salts and potassium salts) thereof: 
##STR2## 
wherein Y.sup.1 denotes a hydrogen atom, --CH.sub.2 COOH or --COOH, and 
Z.sup.1 means a hydrogen atom, 
##STR3## 
Examples of the phosphonic acid type chelating agents include 
iminodimethylphosphonic acid (IDP), alkyldiphosphonic acids (ADPAs) and 
salts (for example, the sodium salts and potassium salts) thereof. 
Examples of the hydroxycarboxylic acid type chelating agents include malic 
acid, citric acid, glycolic acid, heptonic acid, tartaric acid and salts 
(for example, the sodium salts and potassium salts) thereof. 
Examples of the polyelectrolyte type chelating agents (including oligomers) 
include acrylic acid polymers, maleic anhydride polymers, 
.alpha.-hydroxyacrylic acid polymers, itaconic acid polymers, copolymers 
composed of at least two of constituent monomers of these polymers, 
epoxysuccinic acid polymers and salts (for example, the sodium salts and 
potassium salts) thereof. 
Among these chelating agents (c), preferred chelating agents are the 
aminopolycarboxylic acid type chelating agents, aromatic or aliphatic 
carboxylic acid type chelating agents, amino acid type chelating agents, 
ether polycarboxylic acid type chelating agents and hydroxycarboxylic acid 
type chelating agents. Specific examples thereof include EDTA, CDTA, NTA, 
HIMDA, DTPA, EDTA-OH, GEDTA, oxalic acid, succinic acid, pyruvic acid, 
glycine, cysteine, malic acid, citric acid, glycolic acid, heptonic acid, 
tartaric acid, the ether polycarboxylic acids represented by the formula 
(1) and salts thereof. Specific examples of particularly preferred 
chelating agents include DTPA, EDTA, ETA-OH (a compound represented by the 
formula (1) in which Y.sup.1 is CH.sub.2 COOH, and Z.sup.1 is H), 
cysteine, glycine, gluconic acid and salts (the sodium salts, potassium 
salts and the like) thereof. 
The molar ratio (c)/(a) of the components (c) to the component (a) to be 
incorporated is preferably 0.1-3, particularly 0.2-2. If the molar ratio 
is lower than 0.1, the effect of enhancing the herbicidal activity by the 
component (c) cannot be satisfactorily brought about. Even if the molar 
ratio exceeds 3, the effect by the incorporation of the component (c) is 
not markedly improved as compared with the case where the molar ratio is 
3. 
Into the herbicide composition according to the present invention, other 
herbicides, bactericides, pesticides and the like may be incorporated 
within limits not impeding the effects of the present invention. Solvents, 
pH adjustors, inorganic salts, thickeners, coloring matter, perfume bases 
and the like may also be added to the herbicide composition according to 
the present invention as needed. 
The herbicide composition according to the present invention can be 
prepared by a method known per se in the art, for example, by mixing and 
stirring the individual components. The herbicide composition may be 
provided in the form of an aqueous solution, a solid such as powder or 
granules, an aqueous dispersion, or the like. It is preferable to prepare 
a composition in the form of a solid such as powder or granules, or an 
aqueous dispersion of high concentration and dilute it with water at the 
time of use so as to sprinkle the diluted composition where one hopes to 
weed.

EXAMPLES 
The present invention will hereinafter be described in detail by the 
following Examples. However, this invention is not limited to these 
examples. 
Example 1 
(Preparation of herbicide composition) 
An anionic surfactant (sodium butylnaphthalenesulfonate or ammonium lauryl 
sulfate) and ion-exchanged water were used to prepare a 0.01% aqueous 
solution of the anionic surfactant. To the aqueous solution, a 
bipyridinium type herbicide (paraquat, or paraquat and diquat) was added 
to prepare a solution in which 0.01% (100 ppm) of the herbicide was 
contained as an active ingredient. A chelating agent (tetrasodium 
ethylenediaminetetraacetate or pentasodium diethylenetriaminepentaacetate) 
was then added to this solution in a predetermined molar ratio to the 
herbicide, thereby obtaining a herbicide composition. 
(Evaluation method) 
Seeds of crab grass are sowed in pots having an inner diameter of 12 cm, 
into which a soil obtained by mixing fertile soil collected from a paddy 
field, river sand and a commercially-available compost in a weight ratio 
of 7:2:1 is placed, to germinate them. In order to enhance uniformity of 
individuals among the pots, pots in which the growth of crab grass is 
abnormal are discarded. Pots in which crab grass grew to a plant length of 
about 18 cm were used in a test. A herbicide composition sample was 
sprayed on crab grass by means of a spray gun (RG type, manufactured by 
IWATA AIR COMPRESSOR MFG. CO., LTD) in such a manner that it was evenly 
applied to the whole of crab grass in the pots in a proportion 
corresponding to 10 liters/are, thereby evaluating the weed-killing 
efficacy of the sample. 
The evaluation of the weed-killing efficacy was conducted by weighing the 
fresh weight of an above ground part on the third day after the sprinkling 
to determine a percent weeding in accordance with the following equation 
on the basis of the fresh weight of an above ground part in an untreated 
section. The results are shown in Table 1. 
##EQU1## 
TABLE 1 
__________________________________________________________________________ 
Bipyridinium type Chelating agent 
herbicide (%) Anionic surfactant (%) 
(molar ratio (c)/(a)) 
Paraquat/ 
Sodium butyl- 
Ammonium 
Tetrasodium 
Pentasodium 
Percent 
diquat 
naphthalene- 
lauryl 
ethylenediamine- 
diethylenetriamine- 
weeding 
Paraquat (1:1 by wt.) 
sulfonate 
sulfate 
tetraacetate 
pentaacetate 
(%) 
__________________________________________________________________________ 
Inv. 
1 0.01 -- 0.01 -- 0.5 -- 86.4 
prod. 
2 0.01 -- 0.01 -- 1.0 -- 90.2 
3 0.01 -- 0.01 -- 2.0 -- 88.1 
Comp. 
1 0.01 -- -- -- -- -- 72.4 
prod. 
2 0.01 -- 0.01 -- -- -- 46.6 
3 0.01 -- -- -- 0.5 -- 71.9 
Inv. 
4 0.01 -- 0.01 -- -- 0.5 88.6 
prod. 
5 0.01 -- 0.01 -- -- 1.0 89.1 
6 0.01 -- 0.01 -- -- 2.0 91.5 
Comp. 
4 0.01 -- -- -- -- -- 72.4 
prod. 
5 0.01 -- 0.01 -- -- -- 46.6 
6 0.01 -- -- -- -- 0.5 70.9 
Inv. 
7 -- 0.01 -- 0.01 0.5 -- 87.8 
prod. 
8 -- 0.01 -- 0.01 1.0 -- 92.4 
9 -- 0.01 -- 0.01 2.0 -- 88.0 
Comp. 
7 -- 0.01 -- -- -- -- 70.8 
prod. 
8 -- 0.01 0.01 -- -- -- 54.1 
9 -- 0.01 -- -- 0.5 -- 70.5 
__________________________________________________________________________ 
It is understood from Table 1 that when a chelating agent is incorporated 
into a system in which paraquat and/or diquat and an anionic surfactant 
are incorporated, the weed-killing effects of paraquat and diquat are 
enhanced. 
Example 2 
(Preparation of herbicide composition) 
Diluent solutions containing an anionic surfactant and a chelating agent 
either singly or in combination were prepared with ion-exchanged water so 
as to give their corresponding predetermined concentrations shown in Table 
2. Gramoxone.RTM. (containing 30% of paraquat as an active ingredient) and 
Priglox L.RTM. (containing 7% of diquat and 5% of paraquat as active 
ingredients), which are commercially-available bipyridinium type 
herbicides, were diluted with the diluent solutions thus obtained in such 
a manner that the concentrations of the active ingredients in the 
resulting dilute solutions each amounted to 50 ppm, thereby obtaining 
respective herbicide compositions. 
Besides, Gramoxone.RTM. and Priglox L.RTM. were separately diluted with 
ion-exchanged water so as to give an active ingredient concentration of 
100 ppm, thereby preparing dilute solutions as comparative examples. 
(Evaluation method) 
The percent weeding of each test sample was determined in the same manner 
as in Example 1. The results obtained are shown in Table 2. 
TABLE 2 
__________________________________________________________________________ 
Bipyridinium type 
herbicide (a) 
(concentration of (c)/(a) Percent 
original agricultural C (b)/(a) 
(molar weeding 
No. 
chemical) 
(ppm) 
Anionic surfactant (b) 
(ppm) 
Chelating agent (c) 
(ppm) 
(wt. ratio) 
ratio) (%) 
__________________________________________________________________________ 
1 Gramoxone .TM. 
100 -- -- -- -- -- -- 67.5 
2 Gramoxone .TM. 
50 -- -- -- -- -- -- 38.1 
3 Gramoxone .TM. 
50 -- -- EDTA.2Na 32.6 
-- 0.5/1 40.0 
4 Gramoxone .TM. 
50 Ammonium POE(4.5) lauryl 
100 -- -- 2/1 -- 71.3 
ether acetate 
5 Gramoxone .TM. 
50 Ammonium POE(4.5) lauryl 
100 EDTA.2Na 32.6 
2/1 0.5/1 95.1 
ether acetate 
6 Gramoxone .TM. 
50 -- -- Cysteine 17.6 
-- 0.75/1 45.2 
7 Gramoxone .TM. 
50 Triethanolamine POE(3) 
50 -- -- 1/1 -- 64.6 
lauryl ether sulfate 
8 Gramoxone .TM. 
50 Triethanolamine POE(3) 
50 Cysteine 17.6 
1/1 0.75/1 86.9 
lauryl ether sulfate 
9 Gramoxone .TM. 
50 -- -- Na 84.8 
-- 2/1 33.8 
gluconate 
10 Gramoxone .TM. 
50 POE(3) C.sub.12/13 ether 
200 -- -- 4/1 -- 76.3 
phosphoric monoester 
11 Gramoxone .TM. 
50 POE(3) C.sub.12/13 ether 
200 Na 84.8 
4/1 2/1 93.5 
phosphoric monoester 
gluconate 
12 Priglox L .TM. 
100 -- -- -- -- -- -- 65.7 
13 Priglox L .TM. 
50 -- -- -- -- -- -- 35.8 
14 Priglox L .TM. 
50 -- -- ETA-OH 14.6 
-- 0.25/1 37.1 
15 Priglox L .TM. 
50 Castor oil fatty acid 
25 -- -- 0.5/1 
-- 55.2 
potash soap 
16 Priglox L .TM. 
50 Castor oil fatty acid 
25 ETA-OH 14.6 
0.5/1 
0.25/1 88.6 
potash soap 
17 Priglox L .TM. 
50 -- -- Glycine 12.4 
-- 1/1 35.2 
18 Priglox L .TM. 
50 Sodium dodecylbenzene- 
300 -- -- 6/1 -- 68.4 
sulfonate 
19 Priglox L .TM. 
50 Sodium dodecylbenzene- 
300 Glycine 12.4 
6/1 1/1 90.3 
sulfonate 
__________________________________________________________________________ 
POE(): POE means abbreviation of polyoxyethylene, and the inside number o 
a bracket indicates the average mol number of added POE. 
As apparent from Table 2, it is understood that when a chelating agent is 
incorporated into a system in which paraquat and/or diquat and an anionic 
surfactant are incorporated, the weed-killing effects of paraquat and 
diquat are enhanced. 
INDUSTRIAL APPLICABILITY 
According to the present invention, a bipyridinium type herbicide, an 
anionic surfactant and a chelating agent were blended in a certain ratio, 
thereby preventing the bipyridinium type herbicide and the anionic 
surfactant from forming a complex. Therefore, the herbicidal effect of the 
herbicide is markedly enhanced. As a result, the amount of paraquat and/or 
diquat to be used can be made less than ever. Their safety for the human 
body is hence improved. It goes without saying that the compositions 
according to the present invention also retain the spreading effect 
brought about by the incorporation of the anionic surfactant.