Branched wetting agents for enhanced treatment of drought field conditions
This invention relates to multi-branched block copolymers suitable for use as wetting agents. The multi-branched block copolymers are comprised of an oxygen-containing polyfunctional base compound having at least 3 EO/PO block copolymer branches attached thereto. The improvement lies in: (a) the percent hydrophobic component, as defined as the weight % PO in the molecule, being present in an amount from 40% to 60% by weight and in (b) the molecular weight per branch (or arm), as defined as the total number average molecular weight of the polymer divided by the functionality of the base being greater than 1700 gmol −1 arm −1 . It was surprisingly discovered that this combination of intermediate hydrophobicity and high molecular weight give superior drought tolerance for plants treated therewith.
1 . A wetting agent composition comprising:
A. a multi-branched block copolymer comprising:
(a) A polyfunctional base selected from the group consisting of a polyol, a polycarboxylic acid, and a lactone, and
(b) At least three branches attached to the polyfunctional base, wherein:
(i) each branch consists of ethylene oxide and propylene oxide,
(ii) each branch independently comprises an amount of propylene oxide in the range from 40% to 60% by weight based on total alkoxylate content of each branch;
(iii) the molecular weight per branch (or arm), as defined as the total number average molecular weight of the polymer divided by the functionality of the base, is in the range from 1700 gmol −1 arm −1 to 3000 gmol −1 arm −1 ; and
(iv) each branch is terminated with either hydrogen or a hydrophobic end-group; and
B. an alcohol ethoxylate.
2 . The wetting agent composition of claim 1 , wherein the amount of propylene oxide is 50%.
3 . The wetting agent composition of claim 1 , wherein polyols are selected from the group consisting of tri-to octa-hydritic alcohols, glucose, sucrose, maltose, fructose, mannose, galactose, leucrose, and other alditol or sugar molecules.
4 . The wetting agent composition of claim 3 , wherein tri-to octa-hydritic alcohols include pentaerythritol, glycerol, diglycerol, a-methylglucoside, sorbitol, xylitol, mannitol, erythritol, dipentaerythritol, and arabitol.
5 . The wetting agent composition of claim 1 having the following formula:
R 1 —(O—(CH 2 CHR 2 O) x (CH 2 CH 2 O) y COR 3 ) z
wherein:
R 1 is a multi-functional oxygen-containing polyol with at least 3 oxygen-containing reactive sites;
R 2 is CH 3 ;
R 3 is either a hydrophobic end-group which contains a carbon chain with 4 or more carbons or H, with at least one of the groups being the hydrophobic end-group;
x is an integer from 1 to 200;
y is an integer from 1 to 250; and
z is an integer from 3 to 10.
6 . The wetting agent composition of claim 5 , wherein R 3 is a hydrophobic end group containing from 4 to 20 carbons.
7 . The wetting agent composition of claim 5 , wherein x is an integer from 20 to 80.
8 . The wetting agent composition of claim 5 , wherein y is an integer from 100 to 250.
9 . A soil composition comprising the wetting agent composition of claim 1 and a soil mixture.
10 . A method of improving drought tolerance for plants comprising the following steps:
(a) Providing the wetting agent composition of claim 1 ,
(b) Applying the wetting agent composition to a soil-containing turf environment, and
(c) Allowing the wetting agent composition to penetrate the soil-containing turf environment.