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, ii) an isocyanate, and iii) a capping agent; 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 capping agent is selected from the group consisting of a mono alcohol with alkyl chains greater than or equal to C5 and a secondary amine with alkyl chains greater than or equal to C14 capping agents and mixtures thereof; and further wherein the molecular weight of the polyol is 2000.

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 a diisocyanate.

6. A wood preservation composition comprising i) a polyol comprising >95% p-propylene oxide, ii) an isocyanate, and iii) a capping agent; 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 capping agent is selected from the group consisting a mono alcohol with alkyl chains greater than or equal to C5 and a secondary amine with alkyl chains greater than or equal to C14 capping agents and mixtures thereof; and further wherein the molecular weight of the polyol is 2000.

Description

EXAMPLES

Synthesis of Polyurethane Polymers:

[0014] The following polyurethanes were synthesized from a bis hydroxy terminated polypropylene oxide (polyol) and a diisocyanate (IPDI). 150 mL of anhydrous polypropylene oxide in aromatic 200 (solvent, 10-30wt % solution), diisocyanate (2 molar equivalents of isocyanates to hydroxyl groups), was charged with 0.003% of a tin catalyst (dibutyltin dilaurate) to the reactor. A polyol having a molecular weight of 2000 was tested. The reactor was heated to 90° C. with overhead stirring. The reaction mixture was held at 90° C. for 1 h.

[0015] The residual isocyanate, in the polyurethane capped examples, is measured. using Surface SWYPE™ test strips. The reaction product was cooled to room temperature and the capping reagent, mono amine (1 equivalent amine to unreacted isocyanate) was added to cap the remaining isocyanate groups in the reaction mixture. Alternatively, when mono alcohol (1 equivalent hydroxyl to unreacted isocyanate) was used as the capping reagent it was added at 90° C. and reacted for an additional 1 h at 90° C. The reaction is continued at 90° C. until no free isocyanate was observed when tested with SWYPE™ 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.

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.

Calculations of Hansen Solubility Parameters:

[0017] Hansen solubility parameters (HSP) for the various polyurethane end cap segments were computed using HSPiP software (Purchased from https://www.hansen-solubility.com). Predicted HSPs (using the Y-MB method), namely, the HSP for the dispersion (D), polar (P), and hydrogen bonding (H) contributions (all SP in MPa1/2), the total SP (calculated using the predicted HSP), and “End cap distance from diesel” were computed. According to the HSP theory, the distance between two materials is a measure of the solubility. The smaller the distance the more soluble the fluids are within one another. HSP data for a “diesel” was obtained from the literature (Batista et al. J. Am. Oil Chem. Soc. V92, 95, 2015).

δ.sub.T=√{square root over (δ.sub.D.sup.2+δ.sub.P.sup.2+δ.sub.H.sup.2)}

R.sub.a=√{square root over (4(δ.sub.D1−δ.sub.D2).sup.2+4(δ.sub.P1−δ.sub.P2).sup.2+4(δ.sub.H1−δ.sub.H2).sup.2)}

[0018] δ.sub.D1=Dispersive solubility parameter for Diesel=14.51

[0019] δ.sub.D2=Dispersive solubility parameter for a given end group (δ.sub.D)

[0020] δ.sub.P1=Polar solubility parameter for Diesel=3.18

[0021] δ.sub.P2=Polar solubility parameter for a given end group (δ.sub.P)

[0022] δ.sub.H1=H-bonding solubility parameter for Diesel=5.97

[0023] δ.sub.H2=H-bonding solubility parameter for a given end group (δ.sub.H)

TABLE-US-00001 TABLE 1 Diesel Compatibility of PU Polymers with 100% p-iP0 and IPDI with various cap segments (MW = 2000) Diesel compat- Calculated Hansen Solubility ibility Parameters (MPa.sup.1/2) (1 for End Cap Segment wt. %) and “End Cap” distance Polyol Polymer End Capping from “Diesel” (Ra) MW # Reagent δ.sub.T δ.sub.D δ.sub.P δ.sub.H Ra = 2000 Comp 1 Methanol 28.4 19.1 16 13.6 17.5 NO Comp 2 1-Propanol 23.4 17.8 11.5 10 11.3 NO Comp 3 2-Propanol 22.7 17.5 11.4 8.9 10.6 NO Comp 4 1-Butanol 22.7 17.5 10.4 10 10.2 NO Comp 5 2-Butanol 21.8 17.3 9.8 8.9 9.1 NO Comp 6 Sec-Butanol 21.7 17.2 10.1 8.5 9.1 NO EX. 1 1-Pentanol 21.9 17.4 9.5 9.2 9.2 YES EX. 2 1-Hexanol 21.1 17.2 8.9 8.4 8.2 YES EX. 3 1-octanol 19.8 16.9 7.6 6.9 6.6 YES EX. 4 Docosanol 17.1 16.2 4.3 3.4 4.4 YES EX. 5 Propylene 20.9 17 9.2 8 8.1 YES glycol butyl ether Comp 7 Dimethylamine 26.1 18.3 14.3 11.9 14.7 NO Comp 8 Diethylamine 23.1 17.3 12.2 9.3 11.1 NO Comp 9 Di-n- 20.8 16.9 9.3 7.7 8 NO butylamine Comp 10 Di- 19.7 16.5 8.8 6.1 6.9 NO isobutylamine Comp 11 Dihexylamine 19.7 16.7 8.1 6.6 6.6 NO EX. 6 Diheptyamine 19.3 16.6 7.8 6.1 6.2 YES EX. 7 Dioctylamine 18.6 16.5 6.8 5.4 5.4 YES EX. 8 Didecylamine 18.3 16.4 6.3 5 5 YES Comp 12 Benzylamine 26 20.2 12.4 10.7 15.4 NO Comp 13 1-butylamine 25.6 18.1 13.2 12.4 13.9 NO Comp 14 1-octylamine 21.9 17.4 9.9 8.8 9.3 NO Comp 15 1- 20 17 8.1 6.8 7 NO dodecylamine Comp 16 1- 18.6 16.6 6.5 5.2 5.4 NO Octadecylamine

[0024] In accordance with the present invention, mono alcohol with alkyl chains greater than or equal to C5 and secondary amine with alkyl chains greater than or equal to C14 capping agents were compatible

TABLE-US-00002 TABLE 2 Diesel Compatibility of PU Polymers synthesized with 100% p-iPO and MDI with various cap segments (MW = 2000) Diesel com- Calculated Hansen pat- Solubility Parameters ibility (MPa.sup.1/2) for End (1 Cap Segment and wt.%) “End Cap” distance Polyol Polymer End Capping from “Diesel” (Ra) MW # Reagent δ.sub.T δ.sub.D δ.sub.P δ.sub.H Ra = 2000 Comp 17 Methanol 28.4 19.1 16 13.6 17.5 NO Comp 18 1-Butanol 22.7 17.5 10.4 10 10.2 NO EX. 9 1-Pentanol 21.9 17.4 9.5 9.2 9.2 YES EX. 10 Docosanol 17.1 16.2 4.3 3.4 4.4 YES Comp.19 Dimethylamine 26.1 18.3 14.3 11.9 14.7 NO Comp 20 Dihexylamine 19.7 16.7 8.1 6.6 6.6 NO EX. 11 Diheptyamine 19.3 16.6 7.8 6.1 6.2 YES EX. 12 Didecylamine 18.3 16.4 6.3 5 5 YES Comp 21 1-butylamine 25.6 18.1 13.2 12.4 13.9 NO Comp 22 1-Octadecylamine 18.6 16.6 6.5 5.2 5.4 NO

[0025] In accordance with the present invention, mono alcohol with alkyl chains greater than or equal to C5 and secondary amine with alkyl chains greater than or equal to C14 capping agents were compatible