|Title of Invention||
"GLUE FOR CONTROLLING PESTS"
|Abstract||This invention relates to a glue for controlling pests that attack wood or wood products, the glue comprising: a resin in an amount in the range of 50-70%; and bifenthrin in an amount in the range of 0.01-1%, wherein the bifenthrin has a mean particle size of 1-10 um.|
|Full Text||GLUE LINE USE OF BIFENTHRIN IN WOOD PRODUCTS
FIELD OF THE INVENTION
The invention pertains to wood and wood preservation and more particularly
the treatment of wood, wood composites, veneer based products and
engineered wood products during manufacture to protect against attack from
wood destroying organisms (eg. termites, beetles and borers). The active
ingredient is applied via addition to the resin or glue system and results in
treatment of the wood based product through a glue line treatment. Glue line
treatments may be used as a stand alone method or used in conjunction with
surface treatments of wood and engineered wood products using bifenthrin or
other synthetic pyrethroids and/or active chemicals.
This invention also pertains to all products treated by these processes and
BACKGROUND OF THE INVENTION
Bifenthrin is a synthetic pyrethroid insecticide/acaracide that is classified as a
non-cyano pyrethroid. The active ingredient is efficacious to target pests
through both contact and stomach action. As with most synthetic pyrethroids
bifenthrin is active against a wide range of pests including Coleoptera, Diptera,
Heteroptera, Hymenoptera, Homoptera, Isoptera, Lepidoptera, Orthoptera as
well as a number of species of Acarina. Bifenthrin is currently registered in a
number of countries throughout the world for the control of a wide range of
Bifenthrin is used extensively in both crop and non-crop markets including : but
not limited to the cotton, small grains, vegetable, turf and ornamental,
professional pest control, greenhouse, grain protection, home garden and
mosquito control industries. However the art in this field does not indicate that
it was used in the timber preservation industry for the control of subterranean
termites prior to this invention.
Tests have demonstrated that when using conventional treatment methods in
the timber industry, very low rates of bifenthrin are required to protect timber
against attack by termites (eg, Coptotermes spp, Mastotermes
darwiniensis, & Reticulitermes spp). Application rates range from 1 to 20 g
ac/m3 (grams of active ingredient) depending upon the target species.
Standard treatment methods in Australia and around the world currently require
some penetration into the timber by the preservative. This can be achieved by
vacuum pressure, vacuum-vacuum systems that require a treatment vessel
and expensive peripheral and computerized equipment. The process time
required to treat the timber varies depending on the product but takes at least
45 minutes to treat wood. Penetration of preservatives can also be achieved
by diffusion, a process which involves less expensive equipment but requires
much more time and higher levels of stock holding. Wood moisture content is
one of the most important parameters that control diffusion times. Wet wood is
required to achieve diffusion within commercial expectancy. Full penetration of
90 mm thick radiata pine green sapwood can be achieved between 4 to 8
The inclusion of preservatives and active chemicals in glues during the
manufacture of wood composites have been attempted on numerous
occasions and even used by the industry over the years. The current list of
products used in this manner has a number of shortcomings to meet all
requirements of the industry, for example:
Arsenic trioxide is a highly toxic inorganic material that poses an exceptionally
high risk in use. The product has been banned from use in the majority of
western countries with limited use for specific niche applications. Zinc Borate is
another inorganic compound that requires high loadings to be effective. It is
only specific for particle-based composites and not veneer based wood
A number of organophosphate insecticides (Phoxim & Chlorpyrifos) were
recently removed from the Australian Quarantine Inspection Services (AQIS)
list. China and Japan have now banned the use of these products as wood
preservatives for the control of termites. CSIRO studies have shown that
Chlopryrifos treatments at rates specified by different standards fail to protect
the products against termite attack.
Other synthetic pyrethrolds eg., deltamethrin, iambda-cyhalothrin, permethrin
have been found to be either too irritating or unstable under high pH conditions
(approximately 90% of permethrin has shown to be not effective when used for
veneer based products manufactured with phenol formaldehyde resins).
Before this invention the wood and wood composite industry did not have an
effective option for an in-line treatment using preservatives or termiticides
adding to the glue mix during manufacture of the products.
These disclosed processes of treating engineered wood products by adding
bifenthrin in the glue line during the manufacture of plywood, LVL, OSB and
flake boards has not been known to be used in Australia or in any other
Bifenthrin has been found to have specific properties that make it a candidate
for this type of treatment. Bifenthrin is stable under conditions of high pH and
elevated temperature, bonds strongly to organic materials (wood) and is
significantly less water soluble than any other of the active ingredients used or
attempted to be used in the past. Bifenthrin does not present any occupational
health and safety problems and does not instigate pollutants when the treated
product is burnt.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly it is an object of the present invention to provide glue line resin
systems incorporating bifenthrin and methods and apparatus for the use of
such glue line resin systems with bifenthrin as well as wood or engineered
wood products manufactured using those resin and glue systems.
BEST MODE AND OTHER EMBODIMENTS OF THE INVENTION
Bifenthrin has been found also to be very effective when used as a glue line
additive to protect engineered and reconstituted wood products against the
attack of termites and other insects.
When using bifenthrin as an additive for Phenol Formaldehyde (PF) resins,
about 25g ac/m3 and 100 g ac/m3 are required to protect the product against
the attack of subterranean termites (Coptotermes spp and Mastotermes
darwiniensis respectively). The quantifier "g ac/m3" refers to grams of active
ingredient per cubic meter.
Studies conducted using the drum test as described by the Australasian Wood
Preservation Council (AWPC) protocols used a 9-ply 2.5 mm thick veneer
plywood treated with bifenthrin as a glue line additive. Results confirm that low
rates of 25 and 100 g ac/m3 of bifenthrin were sufficient to prevent
subterranean termites (Coptotermes acinaciformis and Mastotermes
darwiniensis respectively) from attacking the specimens. Tables 1 and 2 show
Mean mass loss (%) of softwood plywood treated with bifenthrin as a glue line additive and exposed to subterranean termites (Mastotermes darwiniensis)
Mean mass loss (%) of softwood plywood treated with bifenthrin as a glue line additive and exposed to subterranean termites (Mastotermes darwiniensis)
(Reference: CSIRO Contract Number FFP 00/290 Report Number 995)
Later studies were carried out to demonstrate that bifenthrin added to the glue
line of engineered and reconstituted wood products was effective in preventing
termite attack in products manufactured with s veneer up to 3.2 mm in depth.
These studies were conducted in laboratory conditions in accordance with
AWPC protocols. Results confirm that subterranean termites (Coptotermes
acinaciformis) do not penetrate the glue line at any angle at rates of 25 g
ac/m3. It also demonstrates that plywood manufactured using 2.5 mm veneer
was effective in preventing attack from Mastotermes darwiniensis. (CSIRO
Contract Number FFP 00/290 Report Number 995, CSIRO Contract Number
FFP 01/273 Report Number 1137)
Other studies conducted by CSIRO also confirm that a combination of glue line
additives and face treatment would stop subterranean termite (Mastotermes
darwiniensis) attack at rates lower than 100 g ac /m3. The results show that 50
and 25 g ac/m3 addition of bifenthrin through the glue line and 20g ac/m3
addition in the face veneers provided control equivalent to a standalone glue
line treatment applied at the rate of 100 g ac/m3. (CSIRO Contract Number
FFP 02/337 Report Number 1301)
The repellent effect of bifenthrin as a Glue line additive is significantly
influenced by particle size. This is particularly relevant when veneer based
products are assembled with face veneers 3.2 mm or more in depth.
Formulations that contain a mean particle size (of the active ingredient) of 0.1
um or less will require both a glue line treatment and face treatment to stop
termites from attacking the engineered wood product. However, where the
mean particle size is 1-10 um, surface treatment is not needed. To prove this
concept CSIRO conducted testing in laboratory conditions according to AWPC.
Results confirm this novel concept. When veneer based composites using
veneer thickness of 3.2 mm or more it was found that at equal loadings,
formulations with bigger particle size would protect better the external veneer of
the product. This is illustrated in the following table.
Mass Loss (%w/w) due to termite attack on pluwood treated with bifenthrin
Reference: CSIRO Contract Number FFP.02/337 Report Number 1301; Jim
Creffield 2003 Preliminary Data for Bifenthrin Formulation Comparison)
To have the same effect as formulations that contain larger bifenthrin particle
sizes, formulations with small particle size will require higher loadings to
achieve similar results. (Reference: CSIRO Contract Number FFP 02/337
Report Number 1301; Jim Creffield 2003 Preliminary Data for Bifenthrin
Examples of formulation than can be used include micro-emulsions where the
size particles are very small and the appearance of the solution is translucent,
examples of this are 3 g/L ME formulation (Talstar™ 3 ME); emulsion
concentrates where particles sizes are an average 0.1 um in diameter, an
example of this is Bistar™ EC 100g/L (2.5% to 24% EC); suspension
concentrates where particle size average range normally between 1-1O um, an
example of this is Bistar™ 80 SC ; flowables formulations and wettable powder
(WP) based formulations eg. Talstar™ 10 WP that contains larger particle
sizes than suspension concentrates. This invention does not exclude other
types of formulation containing bifenthrin or any formulation where bifenthrin is
found in combination with other actives.
Bifenthrin is stable at high pH and high temperatures. Phenol formaldehyde
resins have a pH above 12. Phenol formaldehyde is the most common resin
used for plywood and LVL manufacture. This high pH level degrades most
common organic termiticides, bifenthrin is a rare exception. This was
confirmed in a study conducted by QFRI where no degradation was observed
24 hours after mixing bifenthrin with PF resins (Queensland Forest Research
Institute Report prepared by Michael Kennedy - The Stability of Bifenthrin in
Liquid Glues Report 1: Stability in Phenol-Formaldehyde plywood glue 2001).
This stability accounts for other types of resins using in the industry named
urea-formaldehyde, melamine urea-formaldehyde, polyurethane, acrylics,
epoxy and isocyanides resins. Table 4 illustrates representative degradation
thresholds or upper limits for bifenthrin and common organic termiticides.
PH and temperature degradation limits for several organic termiticides
It has been demonstrated, through degradation trials conducted during the
commercial manufacturing of plywood and LVL, that when using a formulation
containing bifenthrin at particle sizes above 1 urn the degradation observed is
less than the one observed in bifenthrin formulations with particle sizes of less
Trials have demonstrated that bifenthrin can be dosed into the glue line during
the batching of the resin mix or just prior to when the glue mix is used in the
glue spreader or in any intermediate area between the batching of the resin
mix and the application of the glue into the plies or before the resin is mixed
into a usable glue.
An example of how to mix bifenthrin formulation during the glue mix is as
follows: (a) Calculate the spread or usage of the glue hi the composite product,
for example that this is 70kg/m3 of a particular product (b) Calculate the
additions required to achieve 25 g/m3 (c) The amount of bifenthrin is calculated
by dividing the 25 g against the 70 kg of glue, this results in 0.36 g of bifenthrin
per kilogram of glue.
If the formulation used is Bistar™ 80 SC that contains 80 g/L of bifenthrin then
0.36 g of bifenthrin will be contained in 4.5 ml of the formulation.
According to the size of glue batch, for example 2000 Kg, it is required to add 9
L of the formulation into the glue mix.
There are several recipes for glues containing phenol formaldehyde resins.
The following is an example to prepare a 1000 kg batch of resin based glue:
615 kg of Phenol formaldehyde resin
119 kg of wheat flour
50 kg of macadamia flour
211.5 L of water
4.5 L of Bistar™ 80 SC
The flour in the glue mixture is an agent added to improve spreadablity.
The bifenthrin formulation can be added to the glue system in several steps of
the manufacturing process, examples of this are: (a) Adding it to the resin or
one component of the resin. This can be done by the resin supplier or by the
end user, (b) Adding during glue batching (c) Adding to the glue transport or
supply line before the glue is delivered to the equipment used to spread the
glue into the laminates; or (d) Adding straight into the tanks of the equipment
used to spread the glue into the plies.
When added protection of the faces is required, pressed products can be
treated by spraying the faces before they have cooled down. This is generally
not needed when the particle size of the bifenthrin is about 1um or larger. The
warmth in the product will create a hot-cold effect that will draw the applying
solution deep into the face. Face treatments can also be applied onto a cold
face, in this case we rely on the lathe checks as a pathway for the penetration
of the chemical. Despite the fact that the penetration of a chemical when
sprayed on cold faces is generally not as good as when spraying on warm
faces, this can be improved by increasing the concentration of the chemical,
increasing the uptake and wetting more of the faces, or by adding surfactants
and chemicals that help the solution penetrate the faces better.
The surface treatment effaces can be done by dipping, rolling, brushing,
deluging, misting and spraying. These systems can be installed in different
areas of the LVL, plywood or any other mill that produces engineered and
reconstituted products either in-line or as a separate and distinct process. This
depends of the lay-out of the production line or lines of a given mill.
The invention contemplates products treated with the above processes and
actives. Examples of these include, without excluding any other products that
are treated in similar manner:
Laminated Veneer Lumber (LVL)
Finger jointed products
Oriented stranded boards (SB)
Stranded Boards (SB)
Glue laminated Lumber (Glu-Lam)
Medium Density Boards (MDF)
And any combination of the above
Bifenthrin can be added to glue systems as described in this invention alone or
in combination with other additives. Examples of these additives are: fungicides
and fire retardants but not excluding other additives.
Among the benefits of using bifenthrin as a glue line additive, in accordance
with the teachings of the invention, are:
1. Low rates of usage.
2. Degradation of the bifenthrin due to elevated pH is minimal in a 24-48
hour time frame. This allows dosing the resin in large batches.
3. Degradation of bifenthrin due to the combination of the high pH of the
resin and the temperature of the process of manufacture is acceptable.
The degradation is less than 50% in a commercial situation.
Similarly bifenthrin can be added to the glue line during the manufacture of
engineered wood products that use other resin systems, e.g., melamine urea
formaldehyde, urea formaldehyde resins, resorcinol, polyurethanes,
isocynates, PVC, acrylics, isocyanates polyethylene and combination or
hybrids in between these examples without excluding other resins and glue
systems. The benefits are:
1. Very low usage rates are required.
2. There is acceptable degradation due to pH of the resin and temperature
of the process.
3. It is easy to dispose of the finished product due to very low or negligible
dioxin emissions during burning of waste containing bifenthrin.
While the invention has been described with reference to particular preferred
details of implementation, these should not be interpreted as limitations to the
scope or spirit of the invention as reflected in the claims.
1. A glue for controlling pests that attack wood or wood products, the glue
comprising: a resin in an amount in the range of 50-70%; and bifenthrin in an
amount in the range of 0.01-1%, wherein the bifenthrin has a mean particle size of
2. The glue as claimed in claim 1, optionally comprising: one or more agents such as
herein described for improving spreadability.
3. The glue as claimed in claim 1, wherein: the concentration of bifenthrin in the glue
results in a concentration of 20- 25 g ac/m3.
4. The glue as claimed in claim 1, wherein: the resin is a phenol formaldehyde resin.
5. The glue as claimed in claim 2, wherein the spreadability improving agent is wheat
6. Wood product onto which the glue of claims 1-4 is applied for preservation or
joining the wood sub-components wherein: the product is any one of the group
comprising laminated veneer lumber, finger jointed products, oriented stranded
boards, stranded boards, glue laminated lumber, particle boards, or medium density
7. A glue for controlling pests that attack wood or wood products substantially as
herein described with reference to the foregoing examples.
|Indian Patent Application Number||2413/DELNP/2005|
|PG Journal Number||25/2008|
|Date of Filing||06-Jun-2005|
|Name of Patentee||FMC AUSTRALASIA PTY LTD.|
|Applicant Address||METROPLEX ON GATEWAY, UNIT 6,9 ARCHIMEDES PLACE, MURRARIE QLD 4172, AUSTRALIA|
|PCT International Classification Number||C09J 11/06|
|PCT International Application Number||PCT/AU2003/001620|
|PCT International Filing date||2003-12-05|