U.S. patent application number 12/240970 was filed with the patent office on 2009-01-29 for micronized wood preservative formulations.
Invention is credited to Robert M. Leach, Jun Zhang.
Application Number | 20090028917 12/240970 |
Document ID | / |
Family ID | 35985233 |
Filed Date | 2009-01-29 |
United States Patent
Application |
20090028917 |
Kind Code |
A1 |
Leach; Robert M. ; et
al. |
January 29, 2009 |
Micronized Wood Preservative Formulations
Abstract
The present invention provides wood preservative compositions
comprising micronized particles. In one embodiment, the composition
comprises dispersions of micronized metal or metal compounds. In
another embodiment, the wood preservative composition comprises an
inorganic component comprising a metal or metal compound and
organic biocide. When the composition comprises an inorganic
component and an organic biocide, the inorganic component or the
organic biocide or both are present as micronized particles. When
compositions of the present invention are used for preservation of
wood, there is minimal leaching of the metal and biocide from the
wood.
Inventors: |
Leach; Robert M.; (Grand
Island, NY) ; Zhang; Jun; (Getzville, NY) |
Correspondence
Address: |
MILBANK, TWEED, HADLEY & MCCLOY LLP
INTERNATIONAL SQUARE BUILDING, 1850 K STRET, N.W., SUITE 1100
WASHINGTON
DC
20006
US
|
Family ID: |
35985233 |
Appl. No.: |
12/240970 |
Filed: |
September 29, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10821326 |
Apr 9, 2004 |
|
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12240970 |
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60461547 |
Apr 9, 2003 |
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60518994 |
Nov 11, 2003 |
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Current U.S.
Class: |
424/409 ;
424/618; 424/630; 424/633; 424/641; 424/646; 424/650; 424/654 |
Current CPC
Class: |
A01N 43/653 20130101;
A01N 43/653 20130101; A01N 59/20 20130101; Y10T 428/662 20150401;
A01N 59/20 20130101; B27K 3/005 20130101; A01N 59/20 20130101; A01N
59/20 20130101; Y10T 428/31989 20150401; A01N 25/04 20130101; A01N
25/04 20130101; A01N 2300/00 20130101; A01N 2300/00 20130101; A01N
25/04 20130101; A01N 25/04 20130101; B27K 3/007 20130101; Y10T
428/268 20150115; A01N 43/653 20130101; Y10T 428/31703 20150401;
B27K 2240/20 20130101; B27K 3/22 20130101; A01N 33/12 20130101;
A01N 25/04 20130101; B27K 3/52 20130101; A01N 43/653 20130101; B27K
3/343 20130101 |
Class at
Publication: |
424/409 ;
424/618; 424/630; 424/646; 424/650; 424/654; 424/641; 424/633 |
International
Class: |
A01N 59/20 20060101
A01N059/20; A01N 59/16 20060101 A01N059/16; A01P 1/00 20060101
A01P001/00; A01P 7/04 20060101 A01P007/04; A01P 3/00 20060101
A01P003/00; A01N 25/12 20060101 A01N025/12 |
Claims
1. A wood preservative composition comprising: (a) an inorganic
component selected from the group consisting of a metal, metal
compound and combinations thereof; and (b) one or more organic
biocides wherein at least the inorganic component or the organic
biocide is present as micronized particles.
2. The composition of claim 1 wherein the inorganic component is
present as micronized particles.
3. The composition of claim 1, wherein the organic biocide is
present as micronized particles.
4. The composition of claim 1, wherein both the inorganic component
and the organic biocide are present as micronized particles.
5. The composition of claim 2, wherein the inorganic component is
selected from the group consisting of copper, cobalt, cadmium,
nickel, tin, silver, zinc and compounds thereof.
6. The composition of claim 2 wherein the micronized inorganic
component is copper, copper compound or combinations thereof.
7. The composition of claim 6, wherein the copper compounds are
selected from the group consisting of copper hydroxide, copper
oxide copper carbonate, basic copper carbonate, copper oxychloride,
copper 8-hydroxyquinolate, copper dimethyldithiocarbamate, copper
omadine and copper borate.
8. The composition of claim 1 wherein the micronized particles have
a size of between 0.005 microns to 25 microns.
9. The composition of claim 8 wherein the micronized particles have
a size of between 0.005 to 10.0 microns.
10. The composition of claim 9 wherein the micronized particles
have a size of between 0.05 to 10.0 microns.
11. The composition of claim 10 wherein the size of the micronized
particles is between 0.05 to 1.0 microns.
12. The composition of claim 7 wherein the organic biocide is
selected from the group consisting of biocides listed in Table
1.
13. The composition of claim 1, wherein the inorganic component is
copper carbonate or copper hydroxide and the organic biocide is a
quaternary ammonium compound selected from the group consisting of
alkyldimethylbenzylammonium chloride, dimethyldidecylammonium
chloride and dimethyldidecylammonium carbonate.
14. The composition of claim 13, wherein the inorganic component is
copper carbonate and the organic biocide is dimethyldidecylammonium
carbonate.
15. The composition of claim 14, wherein the size of the copper
carbonate particles is between 0.05 and 1.0 microns.
16. The composition of claim 12, wherein the inorganic component is
copper carbonate and the organic biocide is tebuconazole.
17. The composition of claim 1, wherein the inorganic component is
a water soluble metal compound and the organic biocide is present
as micronized particles.
18. The composition of claim 17, wherein the inorganic component is
selected from the group consisting of copper nitrate, copper
sulfate and copper acetate.
19. The composition of claim 1, further comprising an agent
selected from the group consisting of water repellants, colorants,
emulsifying agents, dispersants, stabilizers and UV inhibitors.
20. The composition of claim 1, further comprising one or more
enhancing agents.
21. The composition of claim 20, wherein the enhancing agent is a
trialkylamine oxide having the following structure: ##STR00003##
where R.sub.1 is a linear or cyclic C.sub.8 to C.sub.40 saturated
or unsaturated group and R.sub.2 and R.sub.3 independently are
linear C.sub.1 to C.sub.40 saturated or unsaturated groups.
22. The composition of claim 20, wherein the enhancing agent is an
alkoxylated diamine having the following structure: ##STR00004##
where n is an integer which can vary from 1 to 4; R.sub.1, R.sub.2
and R.sub.3 are independently selected from the group consisting of
hydrogen, methyl, ethyl and phenyl; a, b and c are each integers
from 1 to 6; and R4 is fatty alkyl of C8 to C.sub.22.
23-56. (canceled)
Description
[0001] This application claims priority to U.S. Provisional
Application No. 60/461,547, filed Apr. 9, 2003. This application
also claims priority to U.S. Provisional Application No.
60/518,994, filed Nov. 11, 2003, the disclosure of which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention is related generally to the field of
wood preservatives and more particularly to a wood preservative
composition comprising micronized particles.
BACKGROUND OF THE INVENTION
[0003] Wood preserving compositions are well known for preserving
wood and other cellulose-based materials, such as paper,
particleboard, textiles, rope, etc., against organisms responsible
for the destruction of wood, including fungi and insects. Many
conventional wood preserving compositions contain copper amine
complexes. Copper amine complexes have been used in the past
because the amine solubilizes the copper in aqueous solutions. The
copper in such copper amine complexes is obtained from a variety of
copper bearing materials, such as copper scrap, cuprous oxide,
copper carbonate, copper hydroxide, a variety of cuprous and cupric
salts, and copper bearing ores. The amine in such copper amine
complexes is normally obtained from an aqueous solution of ammonia
and ammonium salts, such as ammonium carbonate, and ammonium
sulfate, ethanolamines, et cetera. For example, U.S. Pat. No.
4,622,248 describes forming copper amine complexes by dissolving
copper (II) oxide [CuO] (also known as cupric oxide) in ammonia in
the presence of ammonium bicarbonate.
[0004] The disadvantage of using ammonia as a copper solubilizing
agent lies in the strong odor of ammonia. Additionally, copper
ammonia preservatives can affect the appearance of the treated wood
giving surface residues and undesirable color. In recent years,
many amine-containing compounds, such as the ethanolamines and
aliphatic polyamines, have been used to replace ammonia to
formulate water-soluble copper solutions. These compounds were
chosen because of their strong complexing ability with copper and
because they are essentially odorless. U.S. Pat. no. 4,622,248
discloses a method of preparing copper amine complexes by
dissolving a mixture of copper (II) carbonate [CuCO.sub.3] and
copper (II) hydroxide [Cu(OH).sub.2] in ethanolamine and water. The
complexing amine (i.e., the ligand) and copper (II) ion combine
stoichiometrically and thus the weight ratio of reagents will be
different for each complexing amine. However, copper amine based
preservatives have higher copper loss due to leaching as compared
to traditional copper based preservatives such as chromated copper
arsenate (CCA).
[0005] In addition to metal biocides, existing wood preservatives
can also contain organic biocides. However, many organic biocides
currently in use are not water soluble. Therefore, solubilizing
agents, surfactants and wetting agents are often added to either
solubilize or form emulsions of the organic biocide to formulate a
product that is suitable for the treatment of wood or other
cellulose substrates.
[0006] However, the solubilizing agents, surfactants, and wetting
agents are costly and the use of these products may result in
enhanced leaching of the biocides when the treated material comes
into contact with moisture. Such enhanced leaching is considered to
be the result of the solubilizing agents, surfactants and wetting
agents which remain in the wood after treatment. Because these
compounds continue to cause leaching of the metal and/or biocide
from the treated wood, field performance problems or environmental
issues can result.
[0007] Despite many efforts to address these deficiencies in
existing wood preservatives, there has been an unmet need to
produce aqueous metal-based preservatives that are suitable for
treating wood and other cellulose-based materials while minimizing
the undesirable leaching of metal ions and/or biocide from treated
materials when exposed to water. This need is met by the invention
disclosed herein.
SUMMARY OF THE INVENTION
[0008] The present invention provides micronized compositions for
preservation of wood. In one embodiment, the compositions comprise
metal or metal compounds as micronized particles.
[0009] In another embodiment, the compositions comprise metal or
metal compounds and organic biocides. The metal is in an insoluble
(micronized form). The metal compounds may be in a soluble form or
in a water insoluble (micronized) form. The organic biocides may be
soluble or water insoluble (micronized). In the compositions of
this embodiment, at least one component (either a metal/metal
compound or a biocide) is micronized.
[0010] Accordingly, in one embodiment is provided a wood
preservative composition comprising micronized metal, metal
compounds or combinations thereof.
[0011] In another embodiment is provided a wood preservative
composition comprising a micronized metal or metal compound and a
soluble organic biocide.
[0012] In another embodiment is provided a wood preservative
composition comprising micronized metal/metal compounds and
micronized organic biocides.
[0013] In another embodiment is provided a composition comprising
soluble metal compound and micronized organic biocides.
[0014] Also provided is a method for using the compositions of the
present invention. The method comprises the step of contacting a
cellulosic material, such as wood, with a composition of the
present invention. When the compositions of the present invention
are used for preservation of wood, there is minimal leaching of the
metal or metal and the biocide from wood.
[0015] In one embodiment, the preferred metal for wood preserving
type applications is copper in the form of a copper compound having
a particle size 0.005 microns to 25.0 microns. The copper compound
can optionally be mixed with a variety of water soluble and/or
water insoluble biocides and then vacuum impregnated,
vacuum/pressure or dip impregnated into cellulosic material by
standard methods to effectively preserve the material from agents
that degrade cellulosic material such as fungi, insects, bacteria
etc.
BRIEF DESCRIPTION OF THE FIGURES
[0016] FIG. 1A is a comparison of copper leaching from wood treated
with copper monoethanolamine (copper mea) vs. micronized copper
hydroxide at copper retentions of 0.1 pounds per cubic foot (pcf)
and 0.2 pcf according to American Wood Preservers' Association
(AWPA) Standard E11-97 "Standard Method of Determining the
Leachability of Wood Preservatives".
[0017] FIG. 1B is a comparison of copper leaching from wood treated
with a commercial copper based formulation ACQ-Type D and
micronized copper carbonate plus dimethyldidecylammonium
carbonate/bicarbonate (quat) at preservative retentions of 0.25 pcf
and 0.40 pcf. The leaching test was conducted following the
procedure described in AWPA Standard E11-97 "Standard Method of
Determining the Leachability of Wood Preservatives".
[0018] FIG. 2 depicts the anatomy of coniferous wood.
[0019] FIG. 3 depicts the border pit structure for coniferous
wood.
[0020] FIG. 4A depicts the uniform copper penetration in wood
treated with micronized copper hydroxide according to AWPA Standard
A3-00 "Standard Method for Determining Penetration of Preservatives
and Fire Retardants".
[0021] FIG. 4B depicts the uniform copper penetration in wood
treated with micronized copper carbonate plus quat. The
determination of copper penetration was conducted following the
procedures described in AWPA Standard A3-00 "Standard Method for
Determining Penetration of Preservatives and Fire Retardants".
[0022] FIG. 5 depicts the uniform particle distribution of cupric
oxide through the cells of the wood treated with micronized
CuO.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Unless stated otherwise, such as in the examples, all
amounts and numbers used in this specification are intended to be
interpreted as modified by the term "about". Likewise, all elements
or compounds identified in this specification, unless stated
otherwise, are intended to be non-limiting and representative of
other elements or compounds generally considered by those skilled
in the art as being within the same family of elements or
compounds. The term "micronized" as used herein means a particle
size in the range of 0.005 to 25 microns. The term "preservative"
as used herein means a composition that renders the material to
which it is applied more resistant to insect, fungal and microbial
attack than the same material without having the composition
applied. The term "particle size" refers to the largest axis of the
particle, and in the case of a generally spherical particle, the
largest axis is the diameter.
[0024] The wood preservative compositions of the present invention
comprise an inorganic component comprising a metal, metal compound
or combinations thereof and optionally one or more organic
biocides. Accordingly, the present invention provides micronized
wood preservatives comprising one or more metal or metal compounds
with or without one or more organic biocides. When the composition
comprises both the metal/metal compounds and the organic biocides,
the metal or metal compounds or the organic biocides are present as
water insoluble micronized particles. In one embodiment, both the
inorganic component and the organic biocide are present as
micronized particles.
[0025] These compositions are used for treatment of cellulosic
material such as wood. The leaching of metal from the treated wood
is less for the present compositions than that observed from wood
treated with non-micronized compositions.
[0026] A preferred metal is copper. Accordingly, in one embodiment,
copper or copper compounds are used. The copper or copper compounds
such as cuprous oxide (a source of copper (I) ions), cupric oxide
(a source of copper (II) ions), copper hydroxide, copper carbonate,
basic copper carbonate, copper oxychloride, copper
8-hydroxyquinolate, copper dimethyldithiocarbamate, copper omadine,
copper borate, copper residues (copper metal byproducts) or any
suitable copper source can be used as micronized particles having a
particle size between 0.005 microns to 25 microns. These particles
exhibit a relatively low solubility in water.
[0027] The micronized particles can be obtained by
wetting/dispersing and grinding copper compounds using a
commercially available grinding mill. Alternatively, the micronized
copper compounds may also be purchased from commercial sources,
which generally need to be ground further to be useful for wood
preservation. For example, micronized copper hydroxide can be
obtained from Phibro-Tech, Inc., Sumter, S.C. and ground further
for use in the present invention. Micronized cupric oxide can also
be obtained from Nanophase Technologies Corporation, Romeoville,
Ill.
[0028] The copper source can be mixed with water with or without
addition of a commercially available rheological additive such as a
cellulosic derivative to form a finely dispersed suspension which
can be mixed with a biocide to form a preservative system which is
suitable to treat and protect wood from agents causing degradation.
Other metals or metal compounds as well as transition metals or
transition metal compounds (including the lanthanide and actinide
series elements) such as tin, zinc, cadmium, silver, nickel, etc.
and compounds thereof can be used in place of copper and copper
compounds. The resulting metal dispersion or the metal biocide
fluid dispersion are suitable for the preservation of wood and
other cellulose-based materials.
[0029] The organic biocides useful in the present invention can be
water soluble as well as water insoluble. Such organic biocides
including fungicides, insecticides, moldicides, bactericides,
algaecides etc. are well known to those skilled in the art and
include azoles, quatemary ammonium compounds, borate compounds,
fluoride compounds and combinations thereof.
[0030] Some non-limiting examples of water soluble biocides are
quaternary ammonium compounds, such as alkyldimethylbenzylammonium
chloride, dimethyldidecylammonium chloride, dimethyldidecylammonium
carbonate/bicarbonate and the like.
[0031] Water insoluble organic biocides are also well known. Some
non-limiting examples of water insoluble organic biocides are shown
in Table 1.
TABLE-US-00001 TABLE 1 Organic Biocides Useful for Wood Protection
Name Formula and CAS# Azoles: Cyproconazole
C.sub.15H.sub.18ClN.sub.3O: 94361-06-5 Propiconazole
C.sub.15H.sub.17Cl.sub.2N.sub.3O.sub.2: 60207-90-1 Tebuconazole
C.sub.16H.sub.22ClN.sub.3O: 107534-96-3 Busan (TCMTB)
2-(thiocyanatomethylthio) C.sub.9H.sub.6N.sub.2S.sub.3: 21564-17-0
benzothiazole Chlorothalonil C.sub.8Cl.sub.4N.sub.2: 1897-45-6
Dichlofluanid C.sub.9H.sub.11Cl.sub.2FN.sub.2O.sub.2S.sub.2:
1085-98-9 Isothiazolone: Kathon 930 C.sub.11H.sub.17Cl.sub.2NOS:
64359-81-5 Kathon WT C.sub.4H.sub.4ClNOS: 26172-55-4
Methylisothiazolinone C.sub.4H.sub.5NOS: 2682-20-4
Benzisothiazolin-3-one C.sub.7H.sub.5NOS: 2634-33-5
2-octyl-3-isothiazolone C.sub.11H.sub.19NOS: 26530-20-1
Imidacloprid C.sub.9H.sub.10ClN.sub.5O.sub.2: 138261-41-3
Iodopropynyl Butylcarbamate C.sub.8H.sub.12INO.sub.2: 55406-53-6
(IPBC) Pyrethroids: Bifenthrin C.sub.23H.sub.22ClF.sub.3O.sub.2:
82657-04-3 Cypermethrin C.sub.22H.sub.19Cl.sub.2NO.sub.3:
52315-07-8 Permethrin C.sub.21H.sub.20Cl.sub.2O.sub.3: 52645-53-1
Chitin 1398-61-4 Chitosan 9012-76-4 Clorpyrifos
C.sub.9H.sub.11Cl.sub.3NO.sub.3PS: 2921-88-2 4-cumylphenol
C.sub.15H.sub.16O: 599-64-4 Fipronil
C.sub.12H.sub.4Cl.sub.2F.sub.6N.sub.4OS: 120068-37-3 Carbendazim
C.sub.9H.sub.9N.sub.3O.sub.2: 10605-21-7 Cyfluthrin
C.sub.22H.sub.18Cl.sub.2FNO.sub.3: 68359-37-5 4-alpha-Cumylphenol
C.sub.15H.sub.16O: 599-64-4
[0032] Other biocides such as insecticides, mold inhibitors,
algaecides, bactericides and the like may also be added to the
composition of the present invention.
[0033] The insoluble biocides can be micronized into particles of
submicron size ranging from 0.005 micrometers to 25 micrometers
using a grinding mill. The particles are dispersed in standard
dispersants such as acrylic copolymers, aqueous solution of
copolymers with pigment affinity groups, modified polyacrylate,
acrylic polymer emulsions, modified lignin and the like.
[0034] In one embodiment, micronized metal or metal compounds such
as a copper compound is mixed with an insoluble micronized organic
biocide. The metal or metal compound and the insoluble biocide may
be micronized separately and then mixed or may be mixed first and
then micronized.
[0035] In another embodiment, the metal compound is water soluble.
Example of a suitable water soluble metal compounds are copper
sulfate, copper acetate and copper nitrate. In this embodiment, an
aqueous solution of the copper compound is prepared and then a
micronized dispersion of an organic biocide is added to it.
[0036] Non-biocidal products such as water repellants (such as wax
emulsions), colorants, emulsifying agents, dispersants,
stabilizers, UV inhibitors, enhancing agents (such as trialkylamine
oxides and alkoxylated diamines) and the like may also be added to
the composition disclosed herein to further enhance the performance
of the system or the appearance and performance of the resulting
treated products. Those skilled in the art will recognize that some
of these agents may also have some biocidal properties.
[0037] The trialkylamine oxides have the following structure.
##STR00001##
where R.sub.1 is a linear or cyclic C.sub.8 to C.sub.40 saturated
or unsaturated group and R.sub.2 and R.sub.3 independently are
linear C.sub.1 to C.sub.40 saturated or unsaturated groups.
[0038] The alkoxylated diamines have the following structure:
##STR00002##
where n is an integer which can vary from 1 to 4, R.sub.1, R.sub.2
and R.sub.3 are independently selected from the group consisting of
hydrogen, methyl, ethyl and phenyl, and a, b and c are each
integers which can be 1 to 6, and R4 is fatty alkyl of C.sub.8 to
C.sub.22.
[0039] When wood is treated with micronized wood preservatives
formulations disclosed herein, metal leaching is reduced. For
example, as shown in FIG. 1A, when wood is treated with Cu-MEA
composition the leaching of copper is about 12% and 24%
respectively for 0.1 pcf (pounds per cubic feet) copper and 0.2 pcf
copper. In contrast when the wood is treated with a micronized
composition of the present invention the leaching was only about 2%
and 1% respectively for the 0.1 pcf copper and 0.2 pcf copper.
Copper leaching was evaluated following the procedures described in
American Wood Preservers' Association Standard E11-97.
[0040] Similarly, FIG. 1B is a comparison of copper leaching from
wood treated with a commercial copper based formulation ACQ-Type D
and micronized copper carbonate plus dimethyldidecylammonium
carbonate/bicarbonate (quat) at preservative retentions of 0.25 pcf
and 0.40 pcf. The leaching test was conducted following the
procedure described in AWPA Standard E11-97 "Standard Method of
Determining the Leachability of Wood Preservatives". It can be seen
that wood treated with micronized copper carbonate based
formulation demonstrated much greater copper leaching resistance
than the wood treated with the commercially available preservative
Ammoniacal Copper Quat (ACQ)-Type D.
[0041] Also important is the penetration of the dispersion
formulation into the wood's or other cellulose-based material's
cellular structure. If the copper source used in formulating the
dispersion formulation disclosed herein has a particle size in
excess of 25 microns, the particles may be filtered by the surface
of the wood and thus may not be uniformly distributed within the
cell and cell wall. As shown in FIG. 2, the primary entry and
movement of fluids through wood tissue occurs primarily through the
tracheids and border pits. Tracheids have a diameter of about
thirty microns. Fluids are transferred between wood cells by means
of border pits.
[0042] The overall diameter of the border pit chambers typically
varies from a several microns up to thirty microns while, the
diameter of the pit openings (via the microfibrils) typically
varies from several hundredths of a micron to several microns. FIG.
3 depicts the border pit structure for coniferous woods.
[0043] When wood is treated with micronized preservative
formulation, if the particle size of the micronized preservative is
less than the diameter of the pit openings, a complete penetration
and a uniform distribution of micronized preservative in wood is
expected. FIG. 4A depicts the complete copper penetration in wood
treated with micronized copper hydroxide according to AWPA Standard
A3-00 "Standard Method for Determining Penetration of Preservatives
and Fire Retardants". A uniform blue was observed indicating the
presence of copper. FIG. 4B depicts the complete copper penetration
in wood treated with micronized copper carbonate plus quat. Again,
a uniform blue color was observed indicating the presence of
copper. The determination of copper penetration was conducted
following the procedures described in AWPA Standard A3-00 "Standard
Method for Determining Penetration of Preservatives and Fire
Retardants". FIG. 5 depicts the uniform particle distribution of
cupric oxide through the cells of the wood treated with micronized
CuO through the observation of Scanning Electron Microscope (SEM).
The particles were confirmed to be copper compounds by the use of
SEM-Energy Dispersed X-ray Analysis (EDXA).
[0044] Particle size of the metal, metal compounds or organic
biocide used in the dispersion formulation disclosed herein
typically does not exceed 30 microns or the metal and or organic
biocide used in conjunction with the metal tends to be filtered by
the surface of the wood thus not attaining a desired penetration
and fluid flow through the wood tissue. In one embodiment particle
size of the micronized particles used in the dispersion formulation
disclosed herein can be between 0.005-10 microns. In another
embodiment, the particle size is between 0.005 to 1.0 micron. In
another embodiment, the particle size is between 0.05 to 10.0
microns. If a more uniform penetration is desired, particle size of
the metal/metal compounds or the organic biocide used in the
dispersion formulation disclosed herein can be between 0.05-1.0
microns.
[0045] The present invention also provides a method for
preservation of wood. In one embodiment, the method comprises the
steps of treating wood with a composition (treating fluid)
comprising a dispersion of water insoluble micronized metal and/or
metal compounds. In another embodiment, wood is treated with a
composition comprising a dispersion of micronized metal and/or
metal compounds and organic biocides, wherein the organic biocides
are soluble or present as water insoluble micronized particles. The
size of the micronized particles for the metal/metal compounds and
organic biocide is between 0.005 to 25 microns, preferably between
0.005 to 10 microns, more preferably between 0.05 to 10 micron and
even more preferably between 0.05 to 1.0 microns. In another
embodiment, the wood is treated with a composition comprising
soluble metal compounds and micronized organic biocides.
[0046] The treating fluid may be applied to wood by dipping,
soaking, spraying, brushing, or any other means well known in the
art. In a preferred embodiment, vacuum and/or pressure techniques
are used to impregnate the wood in accord with this invention
including the standard processes, such as the "Empty Cell" process,
the "Modified Full Cell" process and the "Full Cell" process, and
any other vacuum and /or pressure processes which are well known to
those skilled in the art.
[0047] The standard processes are defined as described in AWPA
Standard C1-03 "All Timber Products--Preservative Treatment by
Pressure Processes". In the "Empty Cell" process, prior to the
introduction of preservative, materials are subjected to
atmospheric air pressure (Lowry) or to higher air pressures
(Rueping) of the necessary intensity and duration. In the "Modified
Full Cell", prior to introduction of preservative, materials are
subjected to a vacuum of less than 77 kPa (22 inch Hg) (sea level
equivalent). A final vacuum of not less than 77 kPa (22 inch Hg)
(sea level equivalent) shall be used. In the "Full Cell Process",
prior to introduction of preservative or during any period of
condition prior to treatment, materials are subjected to a vacuum
of not less than 77kPa (22 inch Hg). A final vacuum of not less
than 77 kPa (22 inch Hg) is used.
[0048] The following examples are provided to further describe
certain embodiments of the invention but are in no way meant to
limit the scope of the invention. Examples 1 through 5 demonstrate
the formulation of the concentrated dispersions of copper compounds
and the concentrated dispersions of copper compounds comprising
various organic biocides. Examples 6 through 14 demonstrate the
preparation of treating fluids using concentrated dispersions for
the treatment of wood.
EXAMPLE 1
[0049] 500 g of copper hydroxide were added to a container
containing 1091.7 grams of water and 75.0 grams of commercially
available dispersants/wetting agents. The mixture was mechanically
stirred for 5 minutes and then placed in a grinding mill. The
sample was ground for about 30 minutes, and a stable dispersion
containing about 30% copper hydroxide was obtained. The particle.
size of the copper hydroxide dispersion was analyzed by Horiba
LA-910 Particle Size Distribution Analyzer (PSDA). The average
particle size was 0.195 micrometers (um) with a distribution range
of 0.04 um to 1.5 um.
EXAMPLE 2
[0050] 1000 grams of basic copper carbonate was mixed with 2158.3
grams of water and 175.0 grams of commercially available wetting
agents/dispersants. The mixture was mechanically stirred for 10
minutes. The mixture was then placed in a grinding mill and ground
for about 20 minutes. A stable dispersion was obtained with an
average particle size of 0.199 micrometers.
EXAMPLE 3
[0051] 1000 grams of basic copper carbonate and 20 grams of
tebuconazole were mixed with 3780 grams of water and 200 grams of
wetting agents/dispersants. The mixture was mechanically stirred
for about 10 minutes. The mixture was then placed in a grinding
mill and ground for about 30 minutes. A stable dispersion
containing 25% basic copper carbonate and 0.5% tebuconazole was
obtained with an average particle size of 0.200 micrometers.
EXAMPLE 4
[0052] 300 grams of copper 8-hydroxyquinolate (Cu-8) were mixed
with 855 grams of water and 45 grams of dispersants. The mixture
was mechanically mixed for about 5 minutes and placed in a grinding
mill. The mixture was ground for about 30 minutes and a stable
dispersion containing 25% Cu-8 was obtained with an average
particle size of 0.282 micrometers.
EXAMPLE 5
[0053] A stable cupric oxide (CuO) dispersion containing about 30%
CuO was supplied by Nanophase Technologies, Inc. The average
particle size was about 0.1 micrometers. This can be mixed with
organic soluble or micronized biocides.
EXAMPLE 6
[0054] 38.5g of cupric hydroxide dispersion from Example 1 was
mixed with 7.5 g of N, N-dimethyl-1-dodecylamine-N-oxide (AO) and
2954.0 g of water to produce a preservative treating fluid
containing 0.385% cupric hydroxide and 0.25% AO. The fluid was then
used to treat 2''.times.4''.times.10'' samples of southern pine
sapwood, and sealed with epoxy resin, using an initial vacuum of
28'' Hg for 15 minutes, followed by a pressure cycle of 135 psi for
25 minutes and a final vacuum of 27'' Hg for 10 minutes. The
resulting treated wood was weighed and found to have doubled its
weight. The treated sample was cut and the cross sections sprayed
with a copper indicator to determine copper penetration following
the procedure described in American Wood Preservers' Association
Standard A3-00, and the blue color indicates the presence of
copper. The sample was found to have 100% uniform distribution of
copper throughout the cross section as in FIG. 4A. As a comparison,
FIG. 4A also showed the cross section of untreated wood.
EXAMPLE 7
[0055] 50.0 g CuO dispersion from Example 5 were mixed with 2942.5g
of water and 7.5g of didecyldimethylammonium chloride. The product
was mixed until uniformly dispersed and the treating solution
containing the following compositions was obtained:
TABLE-US-00002 Components Percent Cupric Oxide 0.50
Didecyldimethylammonium Chloride 0.25
A southern pine stake measuring 1.5''.times.3.5''.times.10'' was
placed in a laboratory retort with a vacuum of 27'' Hg for 15
minutes. The treating solution was then pumped into the retort and
the retort pressurized to 130 psi for 30 minutes. The solution was
drained from the retort and the test stake weighed. Based on the
weight pickup, the test stake doubled its weight and showed uniform
penetration of the cupric oxide throughout the wood cross section.
A sample taken from the center portion of the treated wood was
submitted for scanning electron microscopy (SEM) analysis, and the
SEM result indicated the uniform particle distribution in wood as
shown in FIG. 5.
EXAMPLE 8
[0056] 4000g of treating fluid containing 0.31% of cupric oxide and
0.16% didecyldimethylammonium carbonate were prepared by mixing CuO
dispersion from Example 5 and didecyldimethylammonium carbonate.
The fluid was used to treat 2''.times.4''.times.10'' southern pine
samples by placing the samples in a chamber and drawing a 27'' Hg
vacuum for 10 minutes. The treating fluid was then drawn into the
chamber and allowed to stay in contact with the wood cubes for 15
minutes. The fluid was pumped from the chamber and the resulting
wood had more than doubled its weight. Cross sections of the cubes
showed 100% copper penetration.
EXAMPLE 9
[0057] A preservative treating formulation was prepared by adding
0.15 kg of copper carbonate dispersion from Example 2 to 0.025 kg
of N,N-dimethyl-1-hexadecylamine-N-oxide and 4.825 kg of water.
This fluid was allowed to mix until a homogenous fluid was
prepared. This fluid was used to treat southern pine test stakes
measuring 0.156.times.1.5.times.10.0 inchs (4.times.38.times.254
mm) by the full-cell process. The resulting stakes showed a uniform
distribution of copper throughout the wood cells. The treated test
stakes were installed in the field to evaluate the field
performance of the preservative following the procedure described
in AWPA Standard E7-01 "Standard Method of Evaluating Wood
Preservatives by Field Tests with Stakes". The test results
indicated that the treated stakes were resistant to decay and
insect attack. The fluid was also used to treat southern pine wood
cube blocks measuring 3/4''.times.3/4''.times.3/4'' (19 mm.times.19
mm.times.19 mm). The treated cubes were exposed to several test
fungi to evaluate the bio-efficacy of the preservative formulation
following the procedure described in AWPA Standard E10-01 "Standard
Method of Testing Wood Preservatives by Laboratory Soil-Block
Cultures". Upon the completion of the soil-block test, the cubes
were found to have less than 2.0% weight loss, indicating
essentially no fungal attack to the treated cubes. In comparison,
untreated wood cubes had approximately 50% weight loss after being
exposed to the test fungi. The soil block test results indicated
wood treated the above preservative formulation was resistant to
fungal attack.
EXAMPLE 10
[0058] A preservative treating composition was prepared by adding
0.1 kg of dispersion from Example 3 to 4.9 kg of water. The
resulting fluid contained 0.50% copper carbonate and 0.01%
tebuconazole. This fluid was then used to treat full-size lumber
using the full-cell process wherein the wood is initially placed
under a vacuum of 30'' Hg for 30 minutes, followed by the addition
of the treating solution. The system was then pressurized for 30
minutes at 110 psi. A final vacuum of 28'' Hg for 30 minutes was
applied to the wood to remove residual liquid. The wood was found
to contain a uniform distribution of copper throughout the cross
sections and is resistant to fungal and insect attack.
EXAMPLE 11
[0059] 54g of dispersion from Example 3 and 7.5g of N,
N-dimethyl-l-hexadecylamine-N-oxide (AO) were mixed with 2938.5
grams of water to obtain a preservative treating fluid containing
0.45% carbonate, 0.009% tebuconazole and 0.25% AO. The resulting
fluid was used to treat red pine lumber using a modified full-cell
process. The resulting stakes were air-dried and found to a uniform
distribution of copper throughout the cross sections and were
resistant to fungal and insect attack.
EXAMPLE 12
[0060] A preservative treating fluid was prepared by adding 16.0 g
of Cu 8-hydroxyquinolate (Cu-8) dispersion from Example 4 to 3984.0
g of water. The resulting fluid contained 0.1% Cu-8. The fluid was
used to treat southern pine lumber using a full cell process. The
treated stakes were oven dried and found to contain a uniform
distribution of particles throughout the cross sections and were
resistant to fungal and insect attack.
EXAMPLE 13
[0061] A preservative treating fluid was prepared by mixing 175 g
concentrated dispersion containing 20% copper carbonate and 0.5%
cyproconazole with 3325.0 g water. The resulting solution contained
1.0% copper carbonate and 0.025% cyproconazole and was used to
treat southern pine lumber using a full cell process. The treated
stakes were oven dried and found to contain a uniform distribution
of copper and cyproconazole throughout the cross sections and were
resistant to fungal and insect attack.
EXAMPLE 14
[0062] A preservative treating fluid can be prepared by mixing
copper sulfate solution and micronized cyproconazole at a
concentration of 0.25% Cu and 0.01% cyproconazole. The resulting
fluid can be used to treat lumber using a full cell process. The
treated sample can be air-dried for two weeks and tested for
resistance to fungal and termite attack.
[0063] Although specific embodiments have been described herein,
those skilled in the art will recognize that routine modifications
can be made without departing from the spirit of the invention.
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