WOOD PRESERVATIVES

Abstract

A wood preservative composition and method for preserving wood by contacting wood with said composition comprising a polyurethane polymer, non-aqueous solvents, and a wood preservative active.

Claims

1. A method for preserving wood comprising: contacting wood with a wood preservation composition comprising a) a polyurethane polymer synthesized from i) a polyol comprising >95% p-propylene oxide, and ii) an isocyanate b) an organic solvent; and c) at least one wood preservative active selected from among halogenated isothiazolone biocides, halogenated carbamate fungicides and azole fungicides; wherein the isocyanate to polyol molar ratio of the polyurethane polymers is from less than or equal to 0.8 to greater than or equal to 0.1.

2. The method of claim 1 in which the wood preservative active is 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one.

3. The method of claim 1 wherein the organic solvent comprises diesel.

4. The method of claim 1 wherein the polyol comprises 100% p-propylene oxide.

5. The method of claim 1 wherein the isocyanate is methylene bis(4-phenylisocyanate.

6. The method of claim 1 wherein the isocyanate is isophorone diisocyanate.

7. A wood preservation composition comprising a) a polyurethane polymer synthesized from i) a polyol comprising >95% p-propylene oxide, and ii) an isocyanate b) an organic solvent; and c) at least one wood preservative active selected from among halogenated isothiazolone biocides, halogenated carbamate fungicides and azole fungicides; wherein the isocyanate to polyol molar ratio of the polyurethane polymers is from less than or equal to 0.8 to greater than or equal to 0.1.

Description

EXAMPLES

Synthesis of Polyurethane Polymers:

[0014] The following polyurethanes were synthesized from a stoichiometric excess of bis hydroxy terminated polypropylene oxide (polyol) and an isocyanate. 150 mL of anhydrous polypropylene oxide in aromatic 200 (solvent, 10-30 wt % solution) and isocyanate (0.8 molar equivalents of isocyanates to hydroxyl groups), was charged with 0.003% of a Tin catalyst (dibutyltin dilaurate) to the reactor. The reactor was heated to 90° C. with overhead stirring. The reaction mixture was held at 90° C. for 3 h and at that time point no free isocyanate was observed when tested with SWYPEs™ test strips. The polymer solids of the PU solution was estimated from the conversion and the amount of reactants used for the reaction. The polymer solids are calculated as the sum of the reactive components in the synthesis of the polymer.

[0015] Comparative samples 1 to 6 and Examples 2-4 were synthesized following the sample procedure above except that the NCO/OH molar ratio was changed. Comparative samples 7 to 9 and Examples 5-8 were synthesized following the sample procedure except that MDI is used instead of IPDI and NCO/OH molar ratio varied.

Procedure to Determine Diesel Compatibility:

[0016] In a clear, 1 oz vial, 0.1 gram of the polymer (on a 100% polymer solids basis) is diluted with 9.9 grams of diesel fuel (weight/weight) to a 1% solution of the polymer. The sample is maintained at room temperature for 48 hours. After 48 hours, the solution is checked for incompatibility, defined as phase separation, precipitation of the polymer as solids, and/or turbidity.

TABLE-US-00001 TABLE 1 Diesel Compatibility of PU Polymers with 100% p-iPO with IPDI Diesel compatibility (1 wt. %) Polyol Polyol Polyol Polymer Polyol Isocyanate (NCO/OH MW = MW = Mw = # (bis OH) (Bis NCO) molar ratio) 2000 2700 4000 Comp. 1 P4000 IPDI 2 No No No (p-iPO) Comp. 2 P4000 IPDI 1.5 No No No (p-iPO) Comp. 3 P4000 IPDI 1.1 No No No (p-iPO) Comp. 4 P4000 IPDI 1 No No No (p-iPO) Comp. 6 P4000 IPDI 0.9 No No No (p-iPO) Ex-1 P4000 IPDI 0.8 Yes Yes Yes (p-iPO) Ex-2 P4000 IPDI 0.5 Yes Yes Yes (p-iPO) Ex-3 P4000 IPDI 0.25 Yes Yes Yes (p-iPO) Ex-4 P4000 IPDI 0.1 Yes Yes Yes (p-iPO)

TABLE-US-00002 TABLE 2 Diesel Compatibility of PU Polymers with 100% p-iPO with IPDI Diesel compatibility (1 wt. %) Polyol Polyol Polyol Polymer Polyol Isocyanate (NCO/OH MW = MW = Mw = # (bis OH) (Bis NCO) molar ratio) 2000 2700 4000 Comp. 7 P4000 MDI 2 No No No (p-iPO) Comp. 8 P4000 MDI 1.5 No No No (p-iPO) Comp. 9 P4000 MDI 0.9 No No No (p-iPO) Ex-5 P4000 MDI 0.8 Yes Yes Yes (p-iPO) Ex-6 P4000 MDI 0.5 Yes Yes Yes (p-iPO) Ex-8 P4000 MDI 0.1 Yes Yes Yes (p-iPO)