CA1124453A - Protecting wood from wood degrading organisms - Google Patents
Protecting wood from wood degrading organismsInfo
- Publication number
- CA1124453A CA1124453A CA347,151A CA347151A CA1124453A CA 1124453 A CA1124453 A CA 1124453A CA 347151 A CA347151 A CA 347151A CA 1124453 A CA1124453 A CA 1124453A
- Authority
- CA
- Canada
- Prior art keywords
- wood
- solution
- salt
- tannic acid
- metal
- 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
Links
- 239000002023 wood Substances 0.000 title claims abstract description 65
- 230000002633 protecting effect Effects 0.000 title claims abstract description 9
- 230000000593 degrading effect Effects 0.000 title claims abstract description 6
- LRBQNJMCXXYXIU-NRMVVENXSA-N tannic acid Chemical compound OC1=C(O)C(O)=CC(C(=O)OC=2C(=C(O)C=C(C=2)C(=O)OC[C@@H]2[C@H]([C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)O2)OC(=O)C=2C=C(OC(=O)C=3C=C(O)C(O)=C(O)C=3)C(O)=C(O)C=2)O)=C1 LRBQNJMCXXYXIU-NRMVVENXSA-N 0.000 claims abstract description 56
- TUSDEZXZIZRFGC-UHFFFAOYSA-N 1-O-galloyl-3,6-(R)-HHDP-beta-D-glucose Natural products OC1C(O2)COC(=O)C3=CC(O)=C(O)C(O)=C3C3=C(O)C(O)=C(O)C=C3C(=O)OC1C(O)C2OC(=O)C1=CC(O)=C(O)C(O)=C1 TUSDEZXZIZRFGC-UHFFFAOYSA-N 0.000 claims abstract description 55
- 239000001263 FEMA 3042 Substances 0.000 claims abstract description 55
- LRBQNJMCXXYXIU-PPKXGCFTSA-N Penta-digallate-beta-D-glucose Natural products OC1=C(O)C(O)=CC(C(=O)OC=2C(=C(O)C=C(C=2)C(=O)OC[C@@H]2[C@H]([C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)O2)OC(=O)C=2C=C(OC(=O)C=3C=C(O)C(O)=C(O)C=3)C(O)=C(O)C=2)O)=C1 LRBQNJMCXXYXIU-PPKXGCFTSA-N 0.000 claims abstract description 55
- 229940033123 tannic acid Drugs 0.000 claims abstract description 55
- 235000015523 tannic acid Nutrition 0.000 claims abstract description 55
- 229920002258 tannic acid Polymers 0.000 claims abstract description 55
- 150000003839 salts Chemical class 0.000 claims abstract description 28
- 229910052751 metal Inorganic materials 0.000 claims abstract description 27
- 239000002184 metal Substances 0.000 claims abstract description 27
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims abstract description 16
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims abstract description 16
- 238000000034 method Methods 0.000 claims description 35
- 230000008569 process Effects 0.000 claims description 34
- 239000000243 solution Substances 0.000 claims description 24
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 20
- 239000012266 salt solution Substances 0.000 claims description 11
- 229910052742 iron Inorganic materials 0.000 claims description 10
- 230000000536 complexating effect Effects 0.000 claims description 7
- 239000013535 sea water Substances 0.000 claims description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 5
- 239000007864 aqueous solution Substances 0.000 claims description 5
- 229910052802 copper Inorganic materials 0.000 claims description 5
- 239000010949 copper Substances 0.000 claims description 5
- 230000006872 improvement Effects 0.000 claims description 5
- 235000008331 Pinus X rigitaeda Nutrition 0.000 claims description 4
- 235000011613 Pinus brutia Nutrition 0.000 claims description 4
- 241000018646 Pinus brutia Species 0.000 claims description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 3
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims 4
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims 2
- 238000005470 impregnation Methods 0.000 abstract description 25
- 241000233866 Fungi Species 0.000 abstract description 3
- 241000256602 Isoptera Species 0.000 abstract description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- WHRZCXAVMTUTDD-UHFFFAOYSA-N 1h-furo[2,3-d]pyrimidin-2-one Chemical compound N1C(=O)N=C2OC=CC2=C1 WHRZCXAVMTUTDD-UHFFFAOYSA-N 0.000 description 3
- 235000006173 Larrea tridentata Nutrition 0.000 description 3
- 244000073231 Larrea tridentata Species 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 229960002126 creosote Drugs 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 231100000252 nontoxic Toxicity 0.000 description 2
- 230000003000 nontoxic effect Effects 0.000 description 2
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- CPELXLSAUQHCOX-UHFFFAOYSA-M Bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 description 1
- 241000337552 Limnoria Species 0.000 description 1
- 241000237852 Mollusca Species 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 241000065695 Teredo Species 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- 238000006065 biodegradation reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 150000004694 iodide salts Chemical class 0.000 description 1
- 230000005923 long-lasting effect Effects 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 231100001223 noncarcinogenic Toxicity 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000005691 oxidative coupling reaction Methods 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000010186 staining Methods 0.000 description 1
- 239000010875 treated wood Substances 0.000 description 1
- 239000010876 untreated wood Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Landscapes
- Chemical And Physical Treatments For Wood And The Like (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Wood is impregnated with a solution of tannic acid followed by impregnation with a solution of a metal in the form of a salt for protect-ing wood from wood degrading organisms including termites, fungi, and marine borers. The metal selected is one that will complex with both the impregnated tannic acid and the wood, such as ferric chloride.
Wood is impregnated with a solution of tannic acid followed by impregnation with a solution of a metal in the form of a salt for protect-ing wood from wood degrading organisms including termites, fungi, and marine borers. The metal selected is one that will complex with both the impregnated tannic acid and the wood, such as ferric chloride.
Description
~LlZ4453 The invention herein described was made in the course of or under a contract or subcontract thereunder with the Department of the Navy.
Field of the Invention The invention relates to protecting wood from wood degrading organisms including termites, wood attacking fungi and marine borers, such as teredos and Limnoria.
Background of the Invention The inventors herein and another previously introduced a process for protecting wood from marine borers by impregnating the wood with tannic acid. That technique provided an effective, inexpensive, nontoxic, and noncarcinogenic process as an alternative to the well-known use of creosote for that purpose. However, although that process gives relatively long-lasting protection for wood so impregnated, it would plainly be desirable to make such protection last longer still. It would also be desirable to reduce the amount of tannic acid needed for effective protection.
It is known in the field of organic chemistry that tannic acid forms a chemical complex with iron. See Oxidation n ~ Chemistry, ed.
by Trabanoosky, 1973, Chapter 11, "Mechanisms of Phenolic Oxidative Coupling Reactions" by McDonald et al., pp. 97-134, particularly p. 103. It is also :l 20 known in fields relating to work with tissues ~e.g., histochemistry and zoology) that in staining tissue with tannic acid to darken it for visual contrast one can add iron or manganese to make the tissue retain the tannic acid longer.
We have discovered that the resistance of wood impregnated with tannic acid according to the aforesaid joint invention of Chet el at. can be prolonged and that the amount of tannic acid required for the same degree of protection against wood bores, termites, fungi and other sources of biodegradation can be reduced by following tannic acid impregnation with impregnation of the wood with a solution of a metal in the form of a salt, the metal being one that will complex with the tannic acid and the wood.
~1~44S3 This added step is easy and quick to accomplish, requires only inexpensive materials and conventional equipment, and yet gives a marked increase in the duration of borer resistance for wcod so treated and makes possible use of substantially reduced amounts of tannic acid to achieve the result. Further, our invention permits use of cheaper wood, normally very sensitive to marine borers, in marine applications such as in docks, piers, and jetties.
In one aspect, the present invention provides an improved process for protecting wDod which comprises the steps of impregnating wood with a solution of tannic acid in a concentration effective for protection from wood degrading organisms and placing said wood, for use, in seawater, wherein the improvement comprises: the steps, done after said step of impregnating with a solution of tannic acid and before said step of placing in seawater impregnating said wood with a solution of a metal in the form of a salt, said metal being capable of complexing with both the impregnated tannic acid and the wood.
In particular aspects the metallic salt solution is ferric chloride, and it is impregnated under the following conditions: salt concentration is one percent weight per volume of solvent; impregnation is under pressure of 40 psi; and impregnation time is one hour. Ferric chloride is very inexpensive, is nontoxic, and is effective in low concen-trations.
Description of the Preferred Entcdiment A supply of wood to be impregnated is predried, and conventional apparatus for commercial creosote impregnation is utilized. Instead of creosote, a 20 per oent weight per volume solution of cc~merical grade tannic acid in ethanol is used. As used throughout this application, the term "per oe nt weight per volume" means the ratio of the weight of solute in grams to the volume of solvent in milliliters multiplied by one hundred.
The solutic)n is impregnated into the wood under a pressure of 200 psi for twelve hours in the apparatus. Unabsorbed tannic acid is then removed from the apparatus, and a one percent weight per ~lume a~ueous solution of ferric chloride is introduced into the apparatus and impregnated into the ~7 ~1~4453 ~-w~od under pressuxe of 40 psi for one h~ur. The w~od will turn black, indicating that the impre~nated ferric chloride has formed a complex with the impregnated tannic acid and the wood. ~le w~od is then removed frcm the apparatus.
Test Example Block of pine wood (4 inches x 3 inches x 3 inches), provided as test specimens, were predried at 60C. overnight. The blocks were then pla oe d in an impregnator consisting essentially of a pressure cylinder connected through respective valves to a nitr~gen source, a supply of tannic acid in solution (5 percent weight per vDlume in ethanol), and a vacuum ~;4 ~24~53 pump. The tannic acid was obtained from the Sigma Chemical Company, St.
Louis, Missouri. A cap on the cylinder was unscrewed to permit placing the pine blocks in the cylinder, and then tightly screwed back into sealing relation with the cylinder. The cylinder was then evacuated to 3mm Hg by opening the valve connected to the vacuum pump and activating the pump.
This valve was then closed, a second valve was then opened to permit the tannic acid solution to enter the cylinder in an amount sufficient to cover the blocks, and the second valve was then closed. Finally, the third valve was opened to allow nitrogen under pressure (100 psi) to enter the cell.
Impregnation was carried out for two hours.
At the end of the impregnation periodJ the nitrogen valve was then closed, and the tannic acid valve slowly opened to allow unabsorbed tannic acid to flow out of the cylinder into an overflow container. The cylinder was then filled with a 40 percent weight per volume aqueous solution of ferric chloride. Impregnation was carried out under a pressure of 40 psi for four hours. As with the tannic acid, unabsorbed ferric chloride was drained from the cylinder. The blocks were then removed from the cylinder and dried at 60C. overnight. Excess tannic acid and ferric chloride were washed from the blocks by placing them under running water for two hours.
The washing was done primarily so that individuals handling the wood would not have to touch unabsorbed chemicals.
Five blocks each of untreated wood, wood treated with 5 percent tannic acid, and wood treated with 5 percent tannic acid and 40 percent ferric chloride according to the Test Example were placed in an embayment in Ft. Lauderdale, Florida. The water is known to be heavily infested with wood boring teredine mollusks. After nine months the wood was removed and X-rayed for the presence of marine borers. The data are as follows:
Treatment No. of blocks infested by marine borers None 5 5% tannic acid 3 5% tannic acid + 40% ferric chloride 0 _4_ `~'?F '~
~24453 Variations and Modifications As to permissible variations in the practice of the invention, the metal selected need only be one that will form a complex with the tannic acid and the wood and that will go into solution in the form of a salt. A
quick and easy test of whether a given metal has formed the desired complex is visual observation of the wood's turning dark brown or black, indicating that complexing has occurred. A longer but also effective test of complex-ing is to determine whether wood impregnated with tannic acid and a particu-lar salt will give longer borer protection than the same wood treated only with tannic acid, like the test run in the previously described Test Example.
Next to iron, manganese and copper are most preferred. Other metals should be chosen from the standpoint of easy solubility, low cost and, if possible, low toxicity. Instead of the most preferred chloride, the salt can also be a sulfate of the metal chosen. Less preferred but useable are bromide and iodide salts. Concentration of the metal in salt form need not be high because normally very little is needed to complex fully with the wood and tannic acid. Beyond that point additional metal will perform no function.
Generally, concentration of the salt can range from 1 to 50 percent weight per volume and, more preferably, should range from 1 to 10 percent.
Impregnation time and pressure can be varied to vary the amount of impreg-nation, but as just noted, there is normally a relatively low breakpoint be-yond which additional salt impregnation has no effect. In any case impreg-nation time can range from 1 to 12 hours and impregnation pressure from 20 to 100 psi. How long one predries the wood, which one does to make impreg-nation easier, depends on how wet the wood is initially.
As to permissible variations in the step of impregnation with tannic acid, the parameters of tannic acid concentration, impregnation time, and impregnation pressure can be varied to vary the amount of impreg-nation and consequently the length of time the wood remains resistant.
Effective impregnation can be achieved with tannic acid concentration of from 5 to 50 percent weight per volume; the higher the concentration, _5_ generally the longer the resistance of the treated wood. To achieve the same degree of protection, a lower concentration of tannic acid is needed than would otherwise be required without the added step of salt impregnation.
To prolong the protection, one should use the same concentration of tannic acid that he would have used without that added step. Likewise, increasing '~ pressure or time of impregnation extends impregnation effectiveness. The minimum impregnation time is one hour, and the minimum pressure is 50 psi.
The thicker the wood to be impregnated, generally the higher the pressure desirable. In commercial use, excess tannic acid and salt are not washed off after impregnation. Finally, any organic solvent for tannic acid, such as acetone, carbon tetrachloride, or methanol, can be used in place of ethanol as the solvent.
Other embodiments are within the scope of the claims.
.
~ -6-
Field of the Invention The invention relates to protecting wood from wood degrading organisms including termites, wood attacking fungi and marine borers, such as teredos and Limnoria.
Background of the Invention The inventors herein and another previously introduced a process for protecting wood from marine borers by impregnating the wood with tannic acid. That technique provided an effective, inexpensive, nontoxic, and noncarcinogenic process as an alternative to the well-known use of creosote for that purpose. However, although that process gives relatively long-lasting protection for wood so impregnated, it would plainly be desirable to make such protection last longer still. It would also be desirable to reduce the amount of tannic acid needed for effective protection.
It is known in the field of organic chemistry that tannic acid forms a chemical complex with iron. See Oxidation n ~ Chemistry, ed.
by Trabanoosky, 1973, Chapter 11, "Mechanisms of Phenolic Oxidative Coupling Reactions" by McDonald et al., pp. 97-134, particularly p. 103. It is also :l 20 known in fields relating to work with tissues ~e.g., histochemistry and zoology) that in staining tissue with tannic acid to darken it for visual contrast one can add iron or manganese to make the tissue retain the tannic acid longer.
We have discovered that the resistance of wood impregnated with tannic acid according to the aforesaid joint invention of Chet el at. can be prolonged and that the amount of tannic acid required for the same degree of protection against wood bores, termites, fungi and other sources of biodegradation can be reduced by following tannic acid impregnation with impregnation of the wood with a solution of a metal in the form of a salt, the metal being one that will complex with the tannic acid and the wood.
~1~44S3 This added step is easy and quick to accomplish, requires only inexpensive materials and conventional equipment, and yet gives a marked increase in the duration of borer resistance for wcod so treated and makes possible use of substantially reduced amounts of tannic acid to achieve the result. Further, our invention permits use of cheaper wood, normally very sensitive to marine borers, in marine applications such as in docks, piers, and jetties.
In one aspect, the present invention provides an improved process for protecting wDod which comprises the steps of impregnating wood with a solution of tannic acid in a concentration effective for protection from wood degrading organisms and placing said wood, for use, in seawater, wherein the improvement comprises: the steps, done after said step of impregnating with a solution of tannic acid and before said step of placing in seawater impregnating said wood with a solution of a metal in the form of a salt, said metal being capable of complexing with both the impregnated tannic acid and the wood.
In particular aspects the metallic salt solution is ferric chloride, and it is impregnated under the following conditions: salt concentration is one percent weight per volume of solvent; impregnation is under pressure of 40 psi; and impregnation time is one hour. Ferric chloride is very inexpensive, is nontoxic, and is effective in low concen-trations.
Description of the Preferred Entcdiment A supply of wood to be impregnated is predried, and conventional apparatus for commercial creosote impregnation is utilized. Instead of creosote, a 20 per oent weight per volume solution of cc~merical grade tannic acid in ethanol is used. As used throughout this application, the term "per oe nt weight per volume" means the ratio of the weight of solute in grams to the volume of solvent in milliliters multiplied by one hundred.
The solutic)n is impregnated into the wood under a pressure of 200 psi for twelve hours in the apparatus. Unabsorbed tannic acid is then removed from the apparatus, and a one percent weight per ~lume a~ueous solution of ferric chloride is introduced into the apparatus and impregnated into the ~7 ~1~4453 ~-w~od under pressuxe of 40 psi for one h~ur. The w~od will turn black, indicating that the impre~nated ferric chloride has formed a complex with the impregnated tannic acid and the wood. ~le w~od is then removed frcm the apparatus.
Test Example Block of pine wood (4 inches x 3 inches x 3 inches), provided as test specimens, were predried at 60C. overnight. The blocks were then pla oe d in an impregnator consisting essentially of a pressure cylinder connected through respective valves to a nitr~gen source, a supply of tannic acid in solution (5 percent weight per vDlume in ethanol), and a vacuum ~;4 ~24~53 pump. The tannic acid was obtained from the Sigma Chemical Company, St.
Louis, Missouri. A cap on the cylinder was unscrewed to permit placing the pine blocks in the cylinder, and then tightly screwed back into sealing relation with the cylinder. The cylinder was then evacuated to 3mm Hg by opening the valve connected to the vacuum pump and activating the pump.
This valve was then closed, a second valve was then opened to permit the tannic acid solution to enter the cylinder in an amount sufficient to cover the blocks, and the second valve was then closed. Finally, the third valve was opened to allow nitrogen under pressure (100 psi) to enter the cell.
Impregnation was carried out for two hours.
At the end of the impregnation periodJ the nitrogen valve was then closed, and the tannic acid valve slowly opened to allow unabsorbed tannic acid to flow out of the cylinder into an overflow container. The cylinder was then filled with a 40 percent weight per volume aqueous solution of ferric chloride. Impregnation was carried out under a pressure of 40 psi for four hours. As with the tannic acid, unabsorbed ferric chloride was drained from the cylinder. The blocks were then removed from the cylinder and dried at 60C. overnight. Excess tannic acid and ferric chloride were washed from the blocks by placing them under running water for two hours.
The washing was done primarily so that individuals handling the wood would not have to touch unabsorbed chemicals.
Five blocks each of untreated wood, wood treated with 5 percent tannic acid, and wood treated with 5 percent tannic acid and 40 percent ferric chloride according to the Test Example were placed in an embayment in Ft. Lauderdale, Florida. The water is known to be heavily infested with wood boring teredine mollusks. After nine months the wood was removed and X-rayed for the presence of marine borers. The data are as follows:
Treatment No. of blocks infested by marine borers None 5 5% tannic acid 3 5% tannic acid + 40% ferric chloride 0 _4_ `~'?F '~
~24453 Variations and Modifications As to permissible variations in the practice of the invention, the metal selected need only be one that will form a complex with the tannic acid and the wood and that will go into solution in the form of a salt. A
quick and easy test of whether a given metal has formed the desired complex is visual observation of the wood's turning dark brown or black, indicating that complexing has occurred. A longer but also effective test of complex-ing is to determine whether wood impregnated with tannic acid and a particu-lar salt will give longer borer protection than the same wood treated only with tannic acid, like the test run in the previously described Test Example.
Next to iron, manganese and copper are most preferred. Other metals should be chosen from the standpoint of easy solubility, low cost and, if possible, low toxicity. Instead of the most preferred chloride, the salt can also be a sulfate of the metal chosen. Less preferred but useable are bromide and iodide salts. Concentration of the metal in salt form need not be high because normally very little is needed to complex fully with the wood and tannic acid. Beyond that point additional metal will perform no function.
Generally, concentration of the salt can range from 1 to 50 percent weight per volume and, more preferably, should range from 1 to 10 percent.
Impregnation time and pressure can be varied to vary the amount of impreg-nation, but as just noted, there is normally a relatively low breakpoint be-yond which additional salt impregnation has no effect. In any case impreg-nation time can range from 1 to 12 hours and impregnation pressure from 20 to 100 psi. How long one predries the wood, which one does to make impreg-nation easier, depends on how wet the wood is initially.
As to permissible variations in the step of impregnation with tannic acid, the parameters of tannic acid concentration, impregnation time, and impregnation pressure can be varied to vary the amount of impreg-nation and consequently the length of time the wood remains resistant.
Effective impregnation can be achieved with tannic acid concentration of from 5 to 50 percent weight per volume; the higher the concentration, _5_ generally the longer the resistance of the treated wood. To achieve the same degree of protection, a lower concentration of tannic acid is needed than would otherwise be required without the added step of salt impregnation.
To prolong the protection, one should use the same concentration of tannic acid that he would have used without that added step. Likewise, increasing '~ pressure or time of impregnation extends impregnation effectiveness. The minimum impregnation time is one hour, and the minimum pressure is 50 psi.
The thicker the wood to be impregnated, generally the higher the pressure desirable. In commercial use, excess tannic acid and salt are not washed off after impregnation. Finally, any organic solvent for tannic acid, such as acetone, carbon tetrachloride, or methanol, can be used in place of ethanol as the solvent.
Other embodiments are within the scope of the claims.
.
~ -6-
Claims (37)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An improved process for protecting wood which comprises the steps of impregnating wood with a solution of tannic acid in a concentration effective for protection from wood degrading organisms and placing said wood, for use, in seawater, wherein the improvement comprises:
the step, done after said step of impregnating with a solution of tannic acid and before said step of placing in seawater of impregnating said wood with a solution of a metal in the form of a salt, said metal being capable of complexing with both the impregnated tannic acid and the wood.
the step, done after said step of impregnating with a solution of tannic acid and before said step of placing in seawater of impregnating said wood with a solution of a metal in the form of a salt, said metal being capable of complexing with both the impregnated tannic acid and the wood.
2. The process of claim 1 wherein said metal is selected from the group consisting of iron, manganese, and copper.
3. The process of claim 2 wherein said metal is iron.
4. The process of claim 2 wherein said salt is selected from the group consisting of chloride and sulfate salts.
5. The process of claim 3 wherein said salt is ferric chloride.
6. The process of claim 2 wherein said salt solution is impreg-nated under pressure.
7. The process of claim 2 wherein said salt solution has a concen-tration of said salt of from 1 to 50 percent weight per volume.
8. The process of claim 7 wherein said salt concentration is from 1 to 10 percent weight per volume.
9. The process of Claim 8 wherein said salt concentration is 1 percent weight per volume.
10. The process of claim 2 wherein said salt solution is an aqueous solution.
11. The process of claim 1 wherein said wood is pine.
12. The process of claim 6 wherein said pressure is from 20 to 100 psi.
13. The process of claim 12 wherein said impregnating with said salt solution is carried on from 1 to 12 hours.
14. An improved process for protecting wood from wood degrading organisms which comprises impregnating wood with a solution of tannic acid, wherein the improvement comprises:
impregnating said wood, after said impregnating with said solution of tannic acid, with an aqueous solution of ferric chloride under pressure of from 20 to 100 psi for from 1 to 12 hours.
impregnating said wood, after said impregnating with said solution of tannic acid, with an aqueous solution of ferric chloride under pressure of from 20 to 100 psi for from 1 to 12 hours.
15. An article of commerce comprising wood impregnated with a solution of tannic acid and with a solution of a metal in the form of a salt, said metal being capable of complexing both the impregnated tannic acid and the wood.
16. The article of claim 15 wherein said metal is selected from the group consisting of iron, manganese, and copper.
17. An improved process for protecting wood from marine borers which comprises the steps of impregnating wood with a solution of tannic acid in a concentration effective for protection from marine borers and placing said wood, for use, in seawater, wherein the improvement comprises:
the step, done after said step of impregnating with a solution of tannic acid and before said step of placing in seawater of impregnating said wood with a solution of a metal in the form of a salt, said metal being capable of complexing with both the impregnated tannic acid and the wood.
the step, done after said step of impregnating with a solution of tannic acid and before said step of placing in seawater of impregnating said wood with a solution of a metal in the form of a salt, said metal being capable of complexing with both the impregnated tannic acid and the wood.
18. The process of claim 17 wherein said metal is selected from the group consisting of iron, manganese, and copper.
19. The process of claim 18 wherein said metal is iron.
20. The process of claim 18 wherein said salt is selected from the group consisting of chloride and sulfate salts.
21. The process of claim 19 wherein said salt is ferric chloride.
22. The process of claim 18 wherein said salt solution is impreg-nated under pressure.
23. The process of claim 18 wherein said salt solution has a concentration of said salt of from 1 to 50 percent weight per volume.
24. The process of claim 23 wherein said salt concentration is from 1 to 10 percent weight per volume.
25. The process of claim 24 wherein said salt concentration is 1 percent weight per volume.
26. The process of claim 18 wherein said salt solution is an aqueous solution.
27. The process of claim 17 wherein said wood is pine.
28. The process of claim 22 wherein said pressure is from 20 to 100 psi.
29. The process of claim 28 wherein said impregnating with said salt solution is carried on from 1 to 12 hours.
30. An improved process for protecting wood from marine borers which comprises impregnating wood with a solution of tannic acid, wherein the improvement comprises:
impregnating said wood, after said impregnating with said solution of tannic acid, with an aqueous solution of ferric chloride under pressure of from 20 to 100 psi for from 1 to 12 hours.
impregnating said wood, after said impregnating with said solution of tannic acid, with an aqueous solution of ferric chloride under pressure of from 20 to 100 psi for from 1 to 12 hours.
31. An article of commerce, for use in seawater, comprising wood impregnated with a solution of tannic acid and with a solution of a metal in the form of a salt, said metal being capable of complexing with both the impregnated tannic acid and the wood.
32. The article of claim 31 wherein said metal is selected from the group consisting of iron, manganese, and copper.
33. The article of claim 32 wherein said metal is iron and said salt is ferric chloride.
34. The article of claim 32 wherein said salt solution had a salt concentration from 1 to 50 percent weight per volume.
35. The article of claim 32 wherein said wood was impregnated with said tannic acid solution and said salt solution under pressure.
36. The process of claim 30 wherein said ferric chloride has a conoentration from 1 to 50 percent weight per volume.
37. The process of claim 7 or claim 23 wherein the concentration of the tannic acid ranges from 5 to 50% weight per volume.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA347,151A CA1124453A (en) | 1980-03-06 | 1980-03-06 | Protecting wood from wood degrading organisms |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA347,151A CA1124453A (en) | 1980-03-06 | 1980-03-06 | Protecting wood from wood degrading organisms |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1124453A true CA1124453A (en) | 1982-06-01 |
Family
ID=4116425
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA347,151A Expired CA1124453A (en) | 1980-03-06 | 1980-03-06 | Protecting wood from wood degrading organisms |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1124453A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110561570A (en) * | 2019-09-20 | 2019-12-13 | 中国林业科学研究院木材工业研究所 | Complex bamboo, complex bamboo artificial board and preparation method thereof |
-
1980
- 1980-03-06 CA CA347,151A patent/CA1124453A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110561570A (en) * | 2019-09-20 | 2019-12-13 | 中国林业科学研究院木材工业研究所 | Complex bamboo, complex bamboo artificial board and preparation method thereof |
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