CA1245806A - Wood treatment composition - Google Patents
Wood treatment compositionInfo
- Publication number
- CA1245806A CA1245806A CA 537551 CA537551A CA1245806A CA 1245806 A CA1245806 A CA 1245806A CA 537551 CA537551 CA 537551 CA 537551 A CA537551 A CA 537551A CA 1245806 A CA1245806 A CA 1245806A
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- Prior art keywords
- formulation
- quaternary ammonium
- ammonium compound
- group
- chosen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- A01N33/00—Biocides, pest repellants or attractants, or plant growth regulators containing organic nitrogen compounds
- A01N33/02—Amines; Quaternary ammonium compounds
- A01N33/12—Quaternary ammonium compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
- B27K3/16—Inorganic impregnating agents
- B27K3/22—Compounds of zinc or copper
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
- B27K3/34—Organic impregnating agents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
- B27K3/34—Organic impregnating agents
- B27K3/38—Aromatic compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
- B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
- B27K3/52—Impregnating agents containing mixtures of inorganic and organic compounds
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Agronomy & Crop Science (AREA)
- Pest Control & Pesticides (AREA)
- Plant Pathology (AREA)
- Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- Dentistry (AREA)
- General Health & Medical Sciences (AREA)
- Wood Science & Technology (AREA)
- Zoology (AREA)
- Environmental Sciences (AREA)
- Chemical And Physical Treatments For Wood And The Like (AREA)
- Agricultural Chemicals And Associated Chemicals (AREA)
Abstract
WOOD TREATMENT COMPOSITIONS
ABSTRACT
The present invention relates to a composition for rendering wood material resistant to biological deterioration, which composition comprises an aqueous ammoniacal solution of upper and queternary ammonium compounds.
ABSTRACT
The present invention relates to a composition for rendering wood material resistant to biological deterioration, which composition comprises an aqueous ammoniacal solution of upper and queternary ammonium compounds.
Description
3~
FIELD OF INVENTION
The present invention relates to a composition for wood treatment. More particularly it relates to aqueous ammoniacal wood-treating compositions containing copper, and/or zinc, and quaternary ammonium compounds.
~ACKGROUND OF THE ~V~NTIO~/P~ T
In the treatment of wood material to render it resistant to biological attack, i~ is common practice to treat it with a fluid-borne treating chemical. The treatment of the wood material usually comprises soaking or impregnating the wood material with the fluid-borne treating chemical. The second of these techniques which is perhaps the most widely used one is practised in a number of variants, eg. the full cell process, where the pores of the wood material are partially evacuated before impregnation in order to increase the fluid retained therein; or the empty cell process which is similar to the full cell process except that the preliminary step of evacuation is omitted.
One of the more widely used impregnating compositions is an acidic solution of chromium, copper and arsenic. Another aqueous composition commonly used in the impregnation of wood material, comprises an ammoniacal solution of water-insoluble treating chemicals such as salts comprising copper and arsenic. While these compositions are generally satisfactory, they both contain arsenic.
It is therefore the object of this invention to provide an effective wood treating composition having low mammalian toxicity.
BRIEF DESCRIPTION OF THE INVENTI0~7 The formulation of the present invention comprises an aqueous ammoniacal solvent comprising ammonium hydroxide having a wood treating composition dissolved therein, wherein the composi~ion contains ~
quaternary ammonium compound and at least one of copper and zinc, where the quaternary ammonium compound can be represented by the general formula ( RlR2R3R4~ ) X
~wh~re ~l and R2 are independently chosen ~rom ~he group consisting of alkyl groups having 1 to 3 carbon atoms, R3 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, and R4 is chosen from the group consisting of alkyl groups having ~ to 20 carbon atoms, aryl groups and aryl-substituted alkyl groups where the alkyl groups have 1-3 carbon atoms, and X is chosen so as to render the quaternary ammonium compound soluble in the ammoniacal solvent. The ammonium hydroxide concentration is 1.5-2.5 times that of the metall~c species expressed as the metal oxide.
This invention also includes a method of preserving wood which comprises impregnating a wood substrate with a wood preservative formulation comprising an aqueous ammoniacal solvent comprising ammonium hydroxide having a wood treating composition dissolved therein; where said composition contains a quaternary ammonium compound and a metallic cation consisting essentially of at least one of copper and zinc, where said quaternary am~onium compound can be represented by the general formula ~ RlR2R3R4~ ) X
where Rl and R2 are independently chosen from the group consisting of alkyl groups having 1 to 3 carbon atoms, R3 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, and R4 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, aryl groups and aryl-substituted alkyl groups where said substituted alkyl groups have 1 to 3 carbon atoms and X is chosen 80 as to render said quaternary ammonium compound soluble in said ammoniacal solvent where said quaternary ammonium compound and said metallic cation are present in 6aid formulation in biocidally effective amounts, and where the ratio of ^aid quaternary ammonium compound to said metallic cation ranges from a~out .003 to about 30, and the invention extends also to a wood product obtained by the foregoing method.
DETAILED DESCRIPTION OF THE IMVE~TION
Accordingly, the present invention relates to a formulation for the treatment of wood material having acceptable preservative ability and additionally at least partially obviating the problems of the prior art formulations.
As noted above, the formulation comprises an aqueous ammoniacal solvent having a wood treating composition dissolved therein. This composition will comprise a quaternary ammonium compound, and at least one of copper and zinc. The quaternary ammonium compounds ~ contemplated for use in this composition can be represented.by the general formula ( RlR2R3R4N ) X
where Rl and R2 are independently chosen from the group consisting of alkyl groups having 1 to 3 carbon atoms, R3 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, and R4 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, aryl groups and aryl-substituted alkyl groups, where the alkyl groups have 1-3 carbon atoms. ~ne anion X will be chosen so as to solubilize the quaternary ammonium compound and will preferably be chosen from the group consisting of hydroxide, chloride, bromide, nitrate, bisulfate, acetate, bicarbonate and carbonate formate, borate and fatty acid salts. Quaternary ammonium compounds preferred for use in this composition are alkylbenzyldimethylammonium chloride where the alkyl can represent C12 - C16 alkyl groups, and dialkyldimethylammonium chloride, where the alkyl can represent C8 - C12 alkyl groups. The aryl-substituted alkyl group will preferably ~e the benzyl group.
The formulation will be prepared by dissolving metallic copper and/or zinc in the aqueous ammonium hydroxide or by dissolving a sui~able copper or zinc salt such as cuprGus oxide, cupric hydroxide, æinc oxide or cupric carbonate in ammonium hydroxide ~ontaining a suitable amount of anion such as ~luoride, acetate.
carbonate, formate or borate which is added to dissolve the metal in adequate concen~ration. When metallic copper, zinc or cuprous oxide are used, an oxidation of the solution will be required. This can be done by sparging the solution with air; and in this case, the quaternary ammonium compound should be added after its termination in order to avoid excessive foaming.
Quaternary ammonium compounds are usually supplied in the form of a concentrate, at about a 50-80% (by weight) concentration of the compound, and will normally be added as the undiluted concentrate.
Typically, in such compositions, the concentration of the metallic cation in the solution viz.
that of copper and/or zinc will lie in the range of 25 Q.5-lS~, the quaternary ammonium compound from 0.05-15% of the formulation and the ammonia which will be present in sufficient quantity to solubili~e the metallic cations can range from 1-29~ by weight of the solution. The ammonia concentration should be 1.5-2.5 times that of the metallic species expressed as the metal oxide.
Wood material can be treated with this composition in the usual manner (eg. by soaking, impregnating, etc.)~ The composition impregnates wood material relatively easily and following impregnation is highly leach-resistant. Since the quaternary ammonium compound demonstrates an affinity ~or the wood material and is preferentially absorbe~ thereby, low concen~rations may result in inadequate penetration and accordingly it may be necessary to use rela~ively high concentrations of the quaternary ammonium compound if deeper penetration is desired. The empty cel~ treatment may be used in such cases in order to remove exceg6 quaternary ammonium co~pound The composition can be modified in a number of ways which will be evident to tho~e skilled in ths art;
eg. fatty acids for water repellancy or colouring agents can be added to the composition.
The present invention provides an aqueous ammoniacal arsenic-free composition which finds application in wood preservation. Despite its low mammalian toxicity, the formulation has effective biocidal properties as demonstrated by the existence of threshold retention levels for various fungi which are surprisingly less than corresponding values for a conventional arsenic-containing formulation. The significant decrease ~ in the aggregate threshold retention of the preservative, as compared to ths threshold retention levels of the individual components when small amounts of quaternary ammonium compound are added to the ammoniacal copper containing solution strongly su~gests the possibility of synergism between the two components.
The following examples will serve to illustrate the invention.
Example 1 The formulation prepared according to the present invention containing copper added as copper carbonate, alkylbenzyldimethylammonium chloride dissolved in a 3%
ammonium hydroxide solution, was impregnated into 3/4" x 3/4" x 3/4" blocks of red pine ~apwood material at various levels of preservative retention. The blocks were then subjected to leaching with water by soaking them in 50 ml.
of water per block, and changing the water every day for - 6 ~ 5~6 14 da~s. The blocks were air dried to constant weight in a chamber held at 70% R.H. The conditioned blocks were weighed and placed in soil block test jars containing innocula of "Lenzites trabea", "Poria monticola" and "Lentinus lepideus" fungi, in accordance with AWPA soil block test procedur~ M10-77. ~ter 1~ ~eek~, *he ~oil blocks were reweighed, and the minimum level of preservative retention required to result in weight losses of less than 2~ for each species of fungus was determined. These threshold retention levels (in pounds per cubic foot), for various fungi are summarized in Table A below.
This experimental procedure was carried out with two alternative formulations of the present invention lS containing different ratios of copper to the quaternary ammonium compound. For the purposes of comparison, this procedure was repeated using a conventional aqueous ammoniacal solution of copper arsenate, and the corresponding threshold retention values obtained.
An examination of Table A will yield the observation that smaller threshold retentions of the present invention formulations are required to obtain the same level of protection when compared to the conventional formulation.
7. ~2~L5~
TABLE A
CONVENTIONAL ORGANISM THRESHOLV RETENTION
FORMULATIO~ LEVELS
(pounds per cubic foot) Ammoniacal Copper Arsenate Lenzites trabea 0009 Poria monticola 0.14 PRESE~T INVENTIO~
FORMULATION
CuO: Quaternary: 6:1 Lenzites trabea 0.07 Poria monticola 0.09 Lentinus lepideus 0.035 CuO: Quaternary: 2:1 Lenzites trabea 0.07 Poria monticola 0.19 Lentinus lepideus 0.04 .
:
'' ~
.
- 8 - ~2~
Example 2 This example compares the preser~ative properties of the treating solution with the preservative properties of its constituent treating chemicals by comparing the respective threshold retention levels. Procedurally, the experiments in this example are essentially the same as those in the preceding examples. 3/4" x 3/4" x 3/4"
blocks of red pine sapwood material were impre~nated with aqueous ammoniacal solutions of copper carbonate only, the quaternary ammonium compound ABDA only, and the preservative composition having a ratio of copper (as CuO) to quaternary ammonium compound of 4:1. Preservative solutions with copper to quaternary ammonium compound ratios of 6:1 and 2:1 were also impregnated into wood blocks. The blocks were then leached and dried, and placed in soil block test jars which contained innocula of "Lenzites trabea", "Poria monticola" and "Lentinus lepideus". This permitted a determination of the threshold retention levels which are summarized in Table B
below.
An examination of the entries in the table below indicates the efficacy of the formulation taught herein.
In each of the cases, the threshold retention concentration of the present invention formulation was at most equal to (and often less than) the corresponding values for the individual constituents. More particularly, in the case of "Poria monticola", which is tolerant to both copper (threshold retention of 0.5 p.c.f.) and ABDA (threshold retention of 0.2 - 0.~
p.c.f.); the use of the present for~ulation results in a decrease in the retention levels of copper to 0.06 - 0.09 p.c.f. and ABDA to 0.02 - 0.10 p.c.f.; while the total threshold retention level lies in the range 0.09 - 0.19 p.c.f., (depending on the CuO:ABDA ratio) indicating an interaction between the two components.
9 ~ 06 TABLE _ THRESHOLD RETENTIONS
(Leached Blocks) Threshold Retention Concentration at (pcf CuO Threshold Retention (pcf) Preservative Organism + ABDA) CuO ABDA
CuCO3 Lenzites trabea 0.07 0.07 Poria monticola 0.5 0.5 t*) ABDA Lenzites trabea 0.3 - O.3 Poria monticola 0.2-0.4 - 0.2-0.4 Lentinus lepideus 0.07 - 0-07 ~+) ACQ 6:1 Lenzites trabea 0.07 0.05 0.02 Poria monticola 0.09 0.07 0.02 Lentinus lepideus 0.035 0.025 0.010 ACQ 4:1 Lenzites trabea 0.06 0.04 0.02 Poria monticola 0.10 0.06 0.04 Lentinus lepideus 0.016 0.010 0.006 ACQ 2:1 Lenzites trabea 0.07 0.03 0.04 Poria monticola 0.19 0.09 0.10 Lentinus lepideus 0.04 0.02 0.02 (*) ABDA - alkylbenzyldimethylammonium chloride.
[~ ACQ - composition of the present inventiont ratio indicated is that of CuO to ABDA.
.
. ~
Example 3 This example de~onstrate6 the desirable impregnation characteristics of the present invention. A
2" x "2 x 22" piece of Douglas-fir sapwood was end-sealed with epoxy resin and impregnated with a solution containing 1.5% cupric oxide (added as basic copper carbonate), 0.5% ~l~ylbenzyl-di~ethyl~mmonium chloride (ABDA), and 3.0% ammonium hydroxide by applying a v~cuum of 22" of mercury for half an hour and then applying a pressure of 115 psi for 4 1/2 hours at 22C. The retention achieved (CuO ~ ABDA) was 0~58 pcf. After drying, a 2" section was cut from the center of each 22"
piece and this 2" cube was then sectioned so that the retention gradient of the copper and ABDA could be determined. The results for the four faces of the cross-section were averaged and are shown in table C
below, and indicate the desirable impregnation characteristics of the present invention.
TABLE C
PENETRATION INTO DOUGLAS FIR SAPWOOD USING
SOLUTION OF COPPER TO ABDA RATIO OF 2.4:1 ¦CONCENTRATION IN WOOD (~)¦
¦ Location Cu ABDA (*~¦
0-1/8" 3.30 0076 l/8-1/4" 2.22 0.43 ll/4-3/8" 2~11 0.3 l3/8-5/8" 1.93 0.27 15/8-1" 1.93 0.20 _ (*) ABDA: Alkylbenzyldimethylammonium chloride.
Example 4 This example presents the penetration results of the present composition into red pine sapwood. A piece of red pine sapwood was treated ~ith a solution containing 1.5% copper oxide (added as copper carbonate), 2~ of alkylbenzyldimethylammonium chloride (ABDA), and 3% of a~monium hydroxide using .the ~ame tr~at~ent and-analytical procedure as the preceding example. A retention (CuO +
ABDA) o~ 1.2 p.c.f. was obtainedO The penetration results, which are shown in Table D below, indicate the desirable penetration characteristics of the treating solution.
TABLE D
PENETRATION OF RED PINE SAPWOOD WITH
A COPPER TO ABDA RATIO OF 0.6:1 ¦ CONCENTRATION IN WOOD (%)¦
¦ Location Cu ABDA ~*~¦
l0-1/8" 3.66 2.76 l/8-1/4" 1.54 2.13 ll/4-1/2" 1.44 1.52 ll/2-3/4" 1.45 1.37 3/4-1" 1.75 1.74 Modifications to the above will be evident to those skilled in the art, without departiny from the spirit of the invention as defined in the appended claims.
FIELD OF INVENTION
The present invention relates to a composition for wood treatment. More particularly it relates to aqueous ammoniacal wood-treating compositions containing copper, and/or zinc, and quaternary ammonium compounds.
~ACKGROUND OF THE ~V~NTIO~/P~ T
In the treatment of wood material to render it resistant to biological attack, i~ is common practice to treat it with a fluid-borne treating chemical. The treatment of the wood material usually comprises soaking or impregnating the wood material with the fluid-borne treating chemical. The second of these techniques which is perhaps the most widely used one is practised in a number of variants, eg. the full cell process, where the pores of the wood material are partially evacuated before impregnation in order to increase the fluid retained therein; or the empty cell process which is similar to the full cell process except that the preliminary step of evacuation is omitted.
One of the more widely used impregnating compositions is an acidic solution of chromium, copper and arsenic. Another aqueous composition commonly used in the impregnation of wood material, comprises an ammoniacal solution of water-insoluble treating chemicals such as salts comprising copper and arsenic. While these compositions are generally satisfactory, they both contain arsenic.
It is therefore the object of this invention to provide an effective wood treating composition having low mammalian toxicity.
BRIEF DESCRIPTION OF THE INVENTI0~7 The formulation of the present invention comprises an aqueous ammoniacal solvent comprising ammonium hydroxide having a wood treating composition dissolved therein, wherein the composi~ion contains ~
quaternary ammonium compound and at least one of copper and zinc, where the quaternary ammonium compound can be represented by the general formula ( RlR2R3R4~ ) X
~wh~re ~l and R2 are independently chosen ~rom ~he group consisting of alkyl groups having 1 to 3 carbon atoms, R3 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, and R4 is chosen from the group consisting of alkyl groups having ~ to 20 carbon atoms, aryl groups and aryl-substituted alkyl groups where the alkyl groups have 1-3 carbon atoms, and X is chosen so as to render the quaternary ammonium compound soluble in the ammoniacal solvent. The ammonium hydroxide concentration is 1.5-2.5 times that of the metall~c species expressed as the metal oxide.
This invention also includes a method of preserving wood which comprises impregnating a wood substrate with a wood preservative formulation comprising an aqueous ammoniacal solvent comprising ammonium hydroxide having a wood treating composition dissolved therein; where said composition contains a quaternary ammonium compound and a metallic cation consisting essentially of at least one of copper and zinc, where said quaternary am~onium compound can be represented by the general formula ~ RlR2R3R4~ ) X
where Rl and R2 are independently chosen from the group consisting of alkyl groups having 1 to 3 carbon atoms, R3 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, and R4 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, aryl groups and aryl-substituted alkyl groups where said substituted alkyl groups have 1 to 3 carbon atoms and X is chosen 80 as to render said quaternary ammonium compound soluble in said ammoniacal solvent where said quaternary ammonium compound and said metallic cation are present in 6aid formulation in biocidally effective amounts, and where the ratio of ^aid quaternary ammonium compound to said metallic cation ranges from a~out .003 to about 30, and the invention extends also to a wood product obtained by the foregoing method.
DETAILED DESCRIPTION OF THE IMVE~TION
Accordingly, the present invention relates to a formulation for the treatment of wood material having acceptable preservative ability and additionally at least partially obviating the problems of the prior art formulations.
As noted above, the formulation comprises an aqueous ammoniacal solvent having a wood treating composition dissolved therein. This composition will comprise a quaternary ammonium compound, and at least one of copper and zinc. The quaternary ammonium compounds ~ contemplated for use in this composition can be represented.by the general formula ( RlR2R3R4N ) X
where Rl and R2 are independently chosen from the group consisting of alkyl groups having 1 to 3 carbon atoms, R3 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, and R4 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, aryl groups and aryl-substituted alkyl groups, where the alkyl groups have 1-3 carbon atoms. ~ne anion X will be chosen so as to solubilize the quaternary ammonium compound and will preferably be chosen from the group consisting of hydroxide, chloride, bromide, nitrate, bisulfate, acetate, bicarbonate and carbonate formate, borate and fatty acid salts. Quaternary ammonium compounds preferred for use in this composition are alkylbenzyldimethylammonium chloride where the alkyl can represent C12 - C16 alkyl groups, and dialkyldimethylammonium chloride, where the alkyl can represent C8 - C12 alkyl groups. The aryl-substituted alkyl group will preferably ~e the benzyl group.
The formulation will be prepared by dissolving metallic copper and/or zinc in the aqueous ammonium hydroxide or by dissolving a sui~able copper or zinc salt such as cuprGus oxide, cupric hydroxide, æinc oxide or cupric carbonate in ammonium hydroxide ~ontaining a suitable amount of anion such as ~luoride, acetate.
carbonate, formate or borate which is added to dissolve the metal in adequate concen~ration. When metallic copper, zinc or cuprous oxide are used, an oxidation of the solution will be required. This can be done by sparging the solution with air; and in this case, the quaternary ammonium compound should be added after its termination in order to avoid excessive foaming.
Quaternary ammonium compounds are usually supplied in the form of a concentrate, at about a 50-80% (by weight) concentration of the compound, and will normally be added as the undiluted concentrate.
Typically, in such compositions, the concentration of the metallic cation in the solution viz.
that of copper and/or zinc will lie in the range of 25 Q.5-lS~, the quaternary ammonium compound from 0.05-15% of the formulation and the ammonia which will be present in sufficient quantity to solubili~e the metallic cations can range from 1-29~ by weight of the solution. The ammonia concentration should be 1.5-2.5 times that of the metallic species expressed as the metal oxide.
Wood material can be treated with this composition in the usual manner (eg. by soaking, impregnating, etc.)~ The composition impregnates wood material relatively easily and following impregnation is highly leach-resistant. Since the quaternary ammonium compound demonstrates an affinity ~or the wood material and is preferentially absorbe~ thereby, low concen~rations may result in inadequate penetration and accordingly it may be necessary to use rela~ively high concentrations of the quaternary ammonium compound if deeper penetration is desired. The empty cel~ treatment may be used in such cases in order to remove exceg6 quaternary ammonium co~pound The composition can be modified in a number of ways which will be evident to tho~e skilled in ths art;
eg. fatty acids for water repellancy or colouring agents can be added to the composition.
The present invention provides an aqueous ammoniacal arsenic-free composition which finds application in wood preservation. Despite its low mammalian toxicity, the formulation has effective biocidal properties as demonstrated by the existence of threshold retention levels for various fungi which are surprisingly less than corresponding values for a conventional arsenic-containing formulation. The significant decrease ~ in the aggregate threshold retention of the preservative, as compared to ths threshold retention levels of the individual components when small amounts of quaternary ammonium compound are added to the ammoniacal copper containing solution strongly su~gests the possibility of synergism between the two components.
The following examples will serve to illustrate the invention.
Example 1 The formulation prepared according to the present invention containing copper added as copper carbonate, alkylbenzyldimethylammonium chloride dissolved in a 3%
ammonium hydroxide solution, was impregnated into 3/4" x 3/4" x 3/4" blocks of red pine ~apwood material at various levels of preservative retention. The blocks were then subjected to leaching with water by soaking them in 50 ml.
of water per block, and changing the water every day for - 6 ~ 5~6 14 da~s. The blocks were air dried to constant weight in a chamber held at 70% R.H. The conditioned blocks were weighed and placed in soil block test jars containing innocula of "Lenzites trabea", "Poria monticola" and "Lentinus lepideus" fungi, in accordance with AWPA soil block test procedur~ M10-77. ~ter 1~ ~eek~, *he ~oil blocks were reweighed, and the minimum level of preservative retention required to result in weight losses of less than 2~ for each species of fungus was determined. These threshold retention levels (in pounds per cubic foot), for various fungi are summarized in Table A below.
This experimental procedure was carried out with two alternative formulations of the present invention lS containing different ratios of copper to the quaternary ammonium compound. For the purposes of comparison, this procedure was repeated using a conventional aqueous ammoniacal solution of copper arsenate, and the corresponding threshold retention values obtained.
An examination of Table A will yield the observation that smaller threshold retentions of the present invention formulations are required to obtain the same level of protection when compared to the conventional formulation.
7. ~2~L5~
TABLE A
CONVENTIONAL ORGANISM THRESHOLV RETENTION
FORMULATIO~ LEVELS
(pounds per cubic foot) Ammoniacal Copper Arsenate Lenzites trabea 0009 Poria monticola 0.14 PRESE~T INVENTIO~
FORMULATION
CuO: Quaternary: 6:1 Lenzites trabea 0.07 Poria monticola 0.09 Lentinus lepideus 0.035 CuO: Quaternary: 2:1 Lenzites trabea 0.07 Poria monticola 0.19 Lentinus lepideus 0.04 .
:
'' ~
.
- 8 - ~2~
Example 2 This example compares the preser~ative properties of the treating solution with the preservative properties of its constituent treating chemicals by comparing the respective threshold retention levels. Procedurally, the experiments in this example are essentially the same as those in the preceding examples. 3/4" x 3/4" x 3/4"
blocks of red pine sapwood material were impre~nated with aqueous ammoniacal solutions of copper carbonate only, the quaternary ammonium compound ABDA only, and the preservative composition having a ratio of copper (as CuO) to quaternary ammonium compound of 4:1. Preservative solutions with copper to quaternary ammonium compound ratios of 6:1 and 2:1 were also impregnated into wood blocks. The blocks were then leached and dried, and placed in soil block test jars which contained innocula of "Lenzites trabea", "Poria monticola" and "Lentinus lepideus". This permitted a determination of the threshold retention levels which are summarized in Table B
below.
An examination of the entries in the table below indicates the efficacy of the formulation taught herein.
In each of the cases, the threshold retention concentration of the present invention formulation was at most equal to (and often less than) the corresponding values for the individual constituents. More particularly, in the case of "Poria monticola", which is tolerant to both copper (threshold retention of 0.5 p.c.f.) and ABDA (threshold retention of 0.2 - 0.~
p.c.f.); the use of the present for~ulation results in a decrease in the retention levels of copper to 0.06 - 0.09 p.c.f. and ABDA to 0.02 - 0.10 p.c.f.; while the total threshold retention level lies in the range 0.09 - 0.19 p.c.f., (depending on the CuO:ABDA ratio) indicating an interaction between the two components.
9 ~ 06 TABLE _ THRESHOLD RETENTIONS
(Leached Blocks) Threshold Retention Concentration at (pcf CuO Threshold Retention (pcf) Preservative Organism + ABDA) CuO ABDA
CuCO3 Lenzites trabea 0.07 0.07 Poria monticola 0.5 0.5 t*) ABDA Lenzites trabea 0.3 - O.3 Poria monticola 0.2-0.4 - 0.2-0.4 Lentinus lepideus 0.07 - 0-07 ~+) ACQ 6:1 Lenzites trabea 0.07 0.05 0.02 Poria monticola 0.09 0.07 0.02 Lentinus lepideus 0.035 0.025 0.010 ACQ 4:1 Lenzites trabea 0.06 0.04 0.02 Poria monticola 0.10 0.06 0.04 Lentinus lepideus 0.016 0.010 0.006 ACQ 2:1 Lenzites trabea 0.07 0.03 0.04 Poria monticola 0.19 0.09 0.10 Lentinus lepideus 0.04 0.02 0.02 (*) ABDA - alkylbenzyldimethylammonium chloride.
[~ ACQ - composition of the present inventiont ratio indicated is that of CuO to ABDA.
.
. ~
Example 3 This example de~onstrate6 the desirable impregnation characteristics of the present invention. A
2" x "2 x 22" piece of Douglas-fir sapwood was end-sealed with epoxy resin and impregnated with a solution containing 1.5% cupric oxide (added as basic copper carbonate), 0.5% ~l~ylbenzyl-di~ethyl~mmonium chloride (ABDA), and 3.0% ammonium hydroxide by applying a v~cuum of 22" of mercury for half an hour and then applying a pressure of 115 psi for 4 1/2 hours at 22C. The retention achieved (CuO ~ ABDA) was 0~58 pcf. After drying, a 2" section was cut from the center of each 22"
piece and this 2" cube was then sectioned so that the retention gradient of the copper and ABDA could be determined. The results for the four faces of the cross-section were averaged and are shown in table C
below, and indicate the desirable impregnation characteristics of the present invention.
TABLE C
PENETRATION INTO DOUGLAS FIR SAPWOOD USING
SOLUTION OF COPPER TO ABDA RATIO OF 2.4:1 ¦CONCENTRATION IN WOOD (~)¦
¦ Location Cu ABDA (*~¦
0-1/8" 3.30 0076 l/8-1/4" 2.22 0.43 ll/4-3/8" 2~11 0.3 l3/8-5/8" 1.93 0.27 15/8-1" 1.93 0.20 _ (*) ABDA: Alkylbenzyldimethylammonium chloride.
Example 4 This example presents the penetration results of the present composition into red pine sapwood. A piece of red pine sapwood was treated ~ith a solution containing 1.5% copper oxide (added as copper carbonate), 2~ of alkylbenzyldimethylammonium chloride (ABDA), and 3% of a~monium hydroxide using .the ~ame tr~at~ent and-analytical procedure as the preceding example. A retention (CuO +
ABDA) o~ 1.2 p.c.f. was obtainedO The penetration results, which are shown in Table D below, indicate the desirable penetration characteristics of the treating solution.
TABLE D
PENETRATION OF RED PINE SAPWOOD WITH
A COPPER TO ABDA RATIO OF 0.6:1 ¦ CONCENTRATION IN WOOD (%)¦
¦ Location Cu ABDA ~*~¦
l0-1/8" 3.66 2.76 l/8-1/4" 1.54 2.13 ll/4-1/2" 1.44 1.52 ll/2-3/4" 1.45 1.37 3/4-1" 1.75 1.74 Modifications to the above will be evident to those skilled in the art, without departiny from the spirit of the invention as defined in the appended claims.
Claims (20)
1. A formulation comprising an aqueous ammoniacal solvent comprising ammonium hydroxide having a wood treating composition dissolved therein; where said composition contains a quaternary ammonium compound and a metallic cation consisting essentially of at least one of copper and zinc, where said quaternary ammonium compound can be represented by the general formula (R1R2R3R4N+) X-, where R1 and R2 are independently chosen from the group consisting of alkyl groups having 1 to 3 carbon atoms, R3 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, and R4 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, phenyl groups and phenyl-substituted alkyl groups where said substituted alkyl groups have 1-3 carbon atoms, and X is chosen so as to render the quaternary ammonium compound soluble in the ammoniacal solvent, where said quaternary ammonium compound and said metallic cation are present in said formulation in biocidally effective amounts, and where the ratio of said quaternary ammonium compound to said metallic cation ranges from about 0.003 to about 30 and wherein the ammonium hydroxide concentration is 1.5-2.5 times that of the metallic species expressed as the metal oxide.
2. A formulation as defined in claim 1, wherein said phenyl-substituted alkyl group comprises the benzyl group.
3. A formulation as defined in claim 1, wherein X
is chosen from the group comprising chloride, bromide, bisulfate, nitrate, acetate, carbonate and bicarbonate.
is chosen from the group comprising chloride, bromide, bisulfate, nitrate, acetate, carbonate and bicarbonate.
4. A formulation as defined in claim 1, wherein said metallic cation is present in a concentration ranging from about 0.5 to 15% by weight of said formulation.
5. A formulation as defined in claim 1, wherein concentration of said quaternary ammonium compound ranges from about 0.05 to 15% of said formulation.
6. A formulation as defined in claim 1, wherein concentration of ammonia in said solvent lies in the range from about 1 to 28%, and is sufficient to dissolve said metallic cation.
7. A formulation as defined in claim 1, wherein said quaternary ammonium compound is one of alkylbenzyldimethyl chloride and dialkyldimethylammonium chloride.
8. A formulation as defined in claim 1, wherein said metallic cation is copper.
9. A formulation as defined in claim 1, wherein at least one anion chosen from the group consisting of fluoride, acetate, carbonate, formate and borate solubilizes said metallic cation.
10. A method of preserving wood which comprises impregnating a wood substrate with a wood preservative formulation comprising an aqueous ammoniacal solvent comprising ammonium hydroxide having a wood treating composition dissolved therein; where said composition contains a quaternary ammonium compound and at least one of copper and zinc as metallic cations, where the quaternary ammonium compound can by represented by the general formula (R1R2R3R4N+) X-, where R1 and R2 are independently chosen from the group consisting of alkyl groups having 1 to 3 carbon atoms, R3 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, and R4 is chosen from the group consisting of alkyl groups having 8 to 20 carbon atoms, aryl groups and aryl substituted alkyl groups where said substituted alkyl groups have 1-3 carbon atoms, and X is chosen so as to render the quaternary ammonium compound soluble in the ammoniacal solvent where said quaternary ammonium compound and said metallic cation are present in said formulation in biocidally effective amounts, and where the ratio of said quaternary ammonium compound to said metallic cation ranges from about 0.003 to about 30 and where the concentration of ammonium hydroxide expressed as ammonia is about 1.5-2.5 times that of the metallic cation expressed as the metal oxide.
11. The method as defined in claim 10 wherein said aryl-substitute alkyl groups comprises the benzyl group.
12. The method as defined in claim 10 wherein X- is chosen from the group comprising chloride, bromide, bisulfate, nitrate, acetate, carbonate and bicarbonate.
13. The method as defined in claim 10 wherein said metallic cation is present in a concentration ranging from about 0.5 to 15% of weight of said formulation.
14. The method as defined in claim 10 wherein concentration of said quaternary ammonium compound ranges from about 0.05 to 15% of said formulation.
15. The method as defined in claim 10 wherein the concentration of ammonia in said solvent lies in the range from about 1 to 28%, and is sufficient to dissolve said metallic cation.
16. The method as defined in claim 10, wherein said quaternary ammonium compound is one of alkylbenzyldimethyl chloride and dialkyldimethylammonium chloride.
17. The method as defined in claim 100 wherein said metallic cation is copper.
18. The method as defined in claim 10, wherein at least one anion chosen from the group consisting of fluoride, acetate, carbonate, formate and borate solubilizes said metallic cation.
19. A method as defined in claim 10, wherein said impregnating is by the full cell process.
20. A method as defined in claim 10, wherein said impregnating is by the empty cell process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 537551 CA1245806A (en) | 1987-05-20 | 1987-05-20 | Wood treatment composition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 537551 CA1245806A (en) | 1987-05-20 | 1987-05-20 | Wood treatment composition |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA1245806B CA1245806B (en) | |
| CA1245806A true CA1245806A (en) | 1988-12-06 |
Family
ID=4135710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 537551 Expired CA1245806A (en) | 1987-05-20 | 1987-05-20 | Wood treatment composition |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1245806A (en) |
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1987
- 1987-05-20 CA CA 537551 patent/CA1245806A/en not_active Expired
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| Publication number | Publication date |
|---|---|
| CA1245806B (en) |
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