Note: Descriptions are shown in the official language in which they were submitted.
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lj WOOD PRESERVATIVES 84C32
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Il Background of the Invention
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Wood is one of the best structural materials for the construction of
l buildings because of its strength, ease of processing, and relatively low
i cost. Wood, however, has one serious drawback in that it is susceptible to
decay by wood destroying fungi and a-ttacked by wood-worms, borers and ter
mites. Wood is also cosmetically damaged by molds, mildews and stain fungi.
! To eliminate structural dalnage caused by fungi, wood-worms, borers and
termites, wood is traditionally treated with preservatives such as CCA
¦ (copper-chromium-arsenic solutions), pentachlorophenol, creosote oil dnd the
like by pressure impregnation. To eliminate cosmetic darnage, wood is
traditionally irlllnersed in solutions containing salts of chlorinated phenols.
In recent years there has been a demand for wood preservatives which do not
I discolor wood like CCA or creosote and do not contain chlorinated phenols
because of suspected hulnarl safety problems.
Wood preservative compositions comprising didecyldimethyl ammonium
I¦ chloride~as the active ingredient are known to be effective against wood
Il damaging fungi and termites. l~ood preservative compositions comprising
il 3-iodo-2-propynyl butyl carbamate as the active ingredient are known to be
effective against fungi that cduse structural and cosmetic damage to wood.
This invention is directed to syner~istic combinations of these two preser-
vatives.
1!
'1¦Brief Description of the Invention
This invention relates to wood preservative compositions effective in
treating fungi causing rot, mildew, stain and mold. More particularly, this
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invention relates to wood preservative cornpositions comprising a synergistic
combination of didecyldimethyl ammonium chloride (alternatively referred to as
DDMAC) which has the structural formuld:
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CH3~ ~ ~CH3 Cl-
( ~H2)9
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¦¦ and 3-iodo-2-propynyl butyl carbamate (alternatively referred -to as IPBC)
Il which has the structural formula:
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; I I-c-c-cH2-o-c-NH-(cH2)3-cH3
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Detailed Description of the Invention
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I The preservative compositions of the invention can be prepared as
, solutions or emulsions by conventional means using water or organic solvents.
¦ A preferred form is to combine a water solution of DDMAC with an
organic solvent solution of IPBC to create an emulsion. DDMAC acts as a sur-
,I face agent to emulsify the IPBC solution. The resulting emulsion is diluted
~I with water and can be applied to wood by conventional treating methods such as
immersion, brush, spray or pressure.
The quantity and ratio of DDMAC to IPBC will depend upon the specific
i application. Generally, however, the preservative composition will contain
'I from 1 to 80 parts by weight DDMAC per 1 to 10 parts by weight IPBC. A pre-
¦ ferred ratio of DDMAC to IPBC is from 4:1 to 20:1 parts by weight. The sol-
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I vent will generally consist of from 90 to 99 per cent by weight of the total
I wood preservat1ve composition. Typical solvents include combinations of
i water, aromatic solventsg polar solvents dnd aliphdtic solvents.
If des~red, the wood preservative composition may incorporate other
il preservatives. Typ~cal preservatives include pentachlorophenol, zinc
i¦ naphthenate, copper naphthenate and the like.
!~ The following examples will serve to illustrate the invention and
preferred embodiments thereof. All parts and percentages in said examples and
elsewhere in the specification and claims are by weight unless other~ise
indicated.
Ex ~
, Ten red pine samples (lû x 10 x 100 mm) were imlnersed in each preser-
vative compos~tlon, listed in Table 1, for five minutes. DDMAC was obtained
, from Lonza Inc. of FairLawn, New Jersey as a water solution under the trade
il name Bardac,* IP~C was obtained from Iroy Chemical Corporation of Newark, NewJersey as a solvent solution under the trade name Troysan Polyphase AFl.* The
j treated samples were mixed randomly and exposed in dishes to at least three
species of wood damaging fungi. The fungi used were:
Molds White Rot
Asper~illus ni~er Trametes versicolor
l aeci!omyces varioti Trametes s~.
Trichoderlna vlrlde Pol,yporus sp
ocladlum ~,
il Bro Rot Soft Rot
Gloeophylluln trabeum Acremonium strictum
us l~ eus Chaetomiuln ~lobosum
Foria placenta 7~a~hium rubrum
~i Serpula 1 cum2ns
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Mlldew Stain
Aureobasidium pullalaria Chlorociboria aeru~inascens
l Hormiscium sp. Cerotocystis vescus
Torula ~ Diplodia ~E~
iThe exposed samples were incubated for thirty days under conditions
; of 90% relative humidy and 32C temperature to promote fungal growth. After
incubation the degree of fungal attack and decay to each sample W2S measured
'I in square millimeters. The measurements were converted to express the per-
centage of wood surface area protected. The results are shown in Table 1.
The preservative effectiveness for each composition shown in Table 1 is an
'¦ average of ten measurements.
As seen from the data presented in said table, the wood preservative
compositions of the present invention exert an unexpectedly increased wood
preservative effect. The use of combinations of DDMAC and IPBC are more
effective than the use of either compound alone at the same concentration of
preservat;ve.
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Example 2
Samples of pine wood (19 x 19 x 457 mm) were pressure treated with
DDMAC alone, IPBC alone, and a mixture of DDMAC and IPBC. The samples were
,I evaluated according to a standard wood preservative field test (ASTM D1758-
~¦ 74). To obtain substantially equal wood preservative performance, which wasmeasured after six months of exposure, the following concentrations of the
respective preservatives were needed.
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TABLE 2
Kilograms of Preservative per Cubic Meter
of ~ood Required for Protection
IPBC DDMAC DDMAC and IPBC
Molds, Stain 12.80 12.80 5.73 .67
Decay 6.40 12.80 5.73 .67
Termites 12.80 6.40 5.73 .67
As seen from the data presen,ted in Table 2, the use of DDMAC in admixture with
IPBC is generally more effective at much lower concentrations than either
compound used alone.
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