Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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COMPOSITE POLYMER MATRICES FOR CONTROLLED
RELEASE OF SEMIOCIiEMICALS
FIELD OF THE INVENTION
This invention pertains to novel and versatile
devices for use as semiochemical controlled release dis-
pensers. More particularly, hydroxy-terminated polybuta-
diene resins, or other polyols, can be combined with
semiochemicals, additives, and an isocyanate component to
produce a solid phase reservoir surrounded at least par-
tially by a permeable, release rate controlling polymer
membrane.
BACKGROUND OF THE INVENTION
Semiochemicals are an extremely diverse group of
chemicals encompassing many functional groups and having at
least several hundred members. "Law and Regnier (1971)
proposed the tE~rm 'semiochemicals' (Gk. semeon, a mark or
signal) for chemicals that mediate interactions between
living organisms" taken from (Norlund et al. 1981). This
definition is well known and has been in common usage by
persons skilled in the art for many years.
Semiochemicals transmit signals to members of the
same species as well as different species. These chemicals
have been identified in many organisms including bacteria,
yeast, plants, insects and animals. The U.S. Environmental
Protection Agency which regulates certain pest control uses
of semiochemicals has used a slightly narrower definition:
"Chemicals emitted by plants or animals that modify the
behaviour of receptor organisms of like or different kinds
are semiochemicals." (1982 Pesticide Assessment Guidelines,
Subdivision M, Biorational Pesticides [NTIS publication PB-
83153965 page 2]). Often semiochemicals are not emitted as
a pure chemical, but rather as a blend of several com-
pounds. The most studied semiochemicals are the phero-
mones, which transmit chemical signals within the same
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species (The Merck Index 11th ed. 1989) and have been
identified in at least 1,600 species (Mayer and Mclaughlin
1990, Arn et al. 1992). Kairomones, allomones and
synomones are other types of semiochemicals that are intra
species signals (Norlund et al. 1981). Allomones are
compounds that serve to benefit the emitting species, while
kairomones benefit the perceiving species. Synomones are
chemical signals which serve to benefit both the emitting
and perceiving species . It is worth note that the terms
pheromone, allomone and kairomone are not mutually exclus-
ive. For example, a semiochemical may be a pheromone in
one species while the same chemical acts as a kairomone for
predators of that species.
The use of semiochemicals as a tools in inte-
grated pest management (IPM) is increasing. Uses for
semiochemicals have been found in forestry, agriculture and
urban industrial locations (Mitchell 1981, Ridgeway et al.
1990). Other compounds of use in integrated pest manage-
ment also include synthetic chemicals not found naturally
(unnatural chemicals) that mimic the biological actions of
semiochemicals, for example the "male lures" of terphritid
fruit flies (Cunningham et al. 1990) . The chemical mixture
known as "trimedlure" (t-butyl esters of 4- and 5-chloro-
2-methylcyclohexan-1-carboxylic acid) is a secific illus-
tration. The Mediterranean fruit fly, Ceratitis capitata,
does not produce these chemicals, nor are they found in
nature. However, females of this species respond to this
mixture as if it were a male produce sex pheromone. Thus
trimedlure is an unnatural synthetic behaviour-modifying
chemical that mimics the the function of a semiochemical
(sex pheromone). These synthetically prepared, unnatural
chemicals that cause behavoiral responses that copy or
mimic the actions of semiochemicals are herein defined as
an unnatural synthetic behaviour-modifying chemicals and
are functionally equivalent to their corresponding semio-
chemicals. A skilled practitioner will be aware that
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chemicals such as pesticides, fungicides, bactericides,
insecticides, nematocides, acaricides, molluscicides and
growth regulators are not semiochemicals, nor are they
semiochemical mimics.
In contrast to pesticides, semiochemicals do not
work through toxic action and in general are of low toxic-
ity to non-target species (Ridgeway et al. 1992). Pesti-
cides tend to be broad spectrum in the organisms affected
while semiochemicals are much more specific, affecting at
most a few species. Semiochemicals can often replace or
substantially reduce the amount of pesticide needed for
pest control applications. Semiochemical use in pest
management may include strategies such as population
monitoring, quarantine trapping, mass trapping, barrier
trapping, and mating disruption. The use of anti-aggrega-
tion pheromones, alarm pheromones, anti-feedants,
oviposition deterrents, pollination enhancement and other
types of--behaviour modifications are known.
The widespread use of semiochemicals in pest
control applications has been limited partly by diffi-
culties encountered in controlled delivery of the chemicals
to the environment. Semiochemical-based pest management
relies to a large extent on precise slow release device
technology for its successful implementation. For example,
the use of insect pheromones to lure pests to traps used
for population monitoring requires a very specific delivery
rate. Too low a delivery rate may be below the threshold
of perception, while too high a delivery rate may confuse
or repel the insect and prevent the insect from entering
the trap. In other applications such as mating disruption,
too low a release rate or premature exhaustion of slow
release devices can severely reduce the efficacy of the
treatment, while too high a release rate or too long a
lifespan of devices loaded with an expensive semiochemical
may make the cost of treatments prohibitive. Zeoli et al.
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(1982) have summarized controlled release technologies used
for delivering semiochemicals and have categorized the dis-
pensers types into four groups: monolithic systems, lami-
nated structures, reservoir systems without rate control-
s ling membranes and reservoir systems with rate controlling
membranes.
1. Monolithic systems
These one material systems consist of inert
polymeric matrices impregnated with the semiochemical as
the active ingredient (AI). Such homogenous devices are
simple and they lend themselves to a number of applica-
tions. However, the release characteristics depend largely
on the shape of the device, and the capacity of the polymer
to hold the semiochemical, both of which may limit the
longevity of the device. Release of AI from monolithic
devices tends to be logarithmic over time with much of the
active agent being lost in the early part of the device
lifespan. The most constant release from this type of
device usually occurrs when the reservoir is almost
exhausted. Examples of this technology are polyvinyl-
chloride (PVC) impregnated with semiochemical (Fitzgerald
et al. 1973) or silicone rubber impregnated with fragrances
as in U.S. Patent No. 4,725,575 (Union Camp Co.), or sili-
cone-urethane. copolymers used as matrices for dispensing
fragrances or pheromones as in U.S. Patent Nos. 4,908,208
and 5,008,115 (Dow Corning Co.), urethane matrices for
dispensing pesticides as in U.S. Patent No. 4,594,380 (AT&T
Bell Laboratories) or acrylate polymers impregnated with
pheromones (Smith et al. 1991 and Kim et al. 1988).
2. Laminated structures
These devices have relatively good release
characteristics, approaching zero order (constant) release.
However, the manufacture of these devices requires multiple
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processing to produce the laminate. An example of this
technology are laminated dispensers described in U.S.
Patent No. 4,639,393 (Herculite Protective Fabrics), and
German Patent No. 3,524,180 (Montedison S.p.A.).
3. Reservoir systems without rate controlling membranes
These can be exemplified by capillary release
devices as described in U.S. Patent No. 4,017,030 (Albany
International Co.). These devices have been used despite
undesirable high initial losses of semiochemical
(Weatherston et al. 1985) and difficulty in handling.
4. Reservoir systems with a rate controlling membrane
Dispensers of this type generally provide near
constant release characteristics which are governed by a
permeable membrane. The membrane composition and surface
area can be varied to effect changes in the release rates.
Examples are described in U.S. Patent Nos. 4,323,556
(Montedison S.p.A.), 4,445,641 (Bend Research Inc.),
4,979,673 (I. J. Wilk), 4923119 (Shin-Etsu Chemical Co.),
4,793,555 (Dow Corning Corp.) and German Patent No.
2,945,655 (Celamerck G.m.b.H.).
Polyurethane chemistry is well known in the
plastics industry, however the use of these polymers in
semiochemical slow release devices has been limited to
silicone-urethane copolymers. The terminology used herein
to describe the reactants and the reactive process to
produce a polyurethane semiochemical reservoir conforms to
the customary meanings as given in "Polyurethane Handbook"
ed. G. Oertel, Hanser Publishers or "The ICI Polyurethanes
Book", 2nd Edition, ed. G. Woods, published by ICI
Polyurethanes and John Wiley & Sons. The term polyol
refers to a molecule with at least two hydroxyl groups.
Polymeric polyols usually contain other chemical
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functionalities and the most common types of polyols used
in urethane manufacture are polyether polyols (hydroxy-
terminated polyethers) and polyester polyols (hydroxy-
terminated polyesters). Generally polymeric polyols are
not pure compounds, but rather mixtures which are usually
characterized by the average properties of the mixture.
The isocyanates described herein are molecules which
contain at least two isocyanate groups. The term MDI
refers to diphenylmethane diisocyanate (predominately 4,4'
isomer) which is commonly used in industry as mixtures of
pure MDI and polymeric MDI. At the molecular level,
polyurethane polymers may consist of soft block domains
which consist of long chains with few crosslinks, an
elastic structure and a low glass transition temperature,
or hard block domains which consist of highly crosslinked
chains, a rigid structure and a high glass transition
temperature. Some polyurethanes may contain both hard and
soft segments.
The terminology thermoplastic and thermoset
plastic have meanings commonly accepted in the industry,
thermoset plastics cannot be melted without decomposition
and loss of original physical properties while
thermoplastics may be readily melted and cast into molds
without loss of original physical attributes.
SUMMARY OF THE INVENTION
The invention is directed to composite semio-
chemical release devices composed of a homogeneous
polyurethane matrix containing a dissolved or dispersed
active agent and an active agent permeable polymer membrane
which at least partially surrounds the matrix. The polymer
matrix is prepared from a reactive mixture comprising a
polyol and an isocyanate cross linking agent reacted in the
presence of unreactive semiochemicals and additives.
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The term composite polymer device has been used
herein to indicate that the devices are constructed from at
least a binary combination of separate polymers, namely a
homogeneous polyurethane core containing a semiochemical
active ingredient and a semiochemical permeable, separate
polymer membrane at least partially surrounding the
polyurethane core.
The polyol may be selected from the group con-
sisting of hydroxy-terminated polybutadiene resins, poly-
ether polyols, polyester polyols and mixtures thereof. The
isocyanate component may be selected from the group con-
sisting of monomeric or polymeric diphenylmethane diiso-
cyanates, toluene diisocyanates, isophorone diisocyanate
and hexamethylene diisocyanate or mixtures thereof. Semio-
chemicals compatible with the reactive process may be
selected from the functional groups including: alkanes,
alkenes, aromatic hydrocarbons, ethers, esters, epoxides,
aldehydes, ketones, lactones, nitriles, imines, tertiary
amines, thioethers, sulfoxides, sulfones, disulfide com-
pounds, thioesters, organohalides, and mixtures thereof.
Semiochemicals not compatible or reactive with the matrix
include the functional groups: alcohols, carboxylic acids,
thiols, primary and secondary amines, and phenols.
The reaction mixture may include anti-oxidants,
ultraviolet light absorbers, pigments, dyes, fillers,
blowing agents, plasticizers, other resin modifying agents
and mixtures thereof.
The reaction mixture is polymerized in a device
at least partially surrounded by a polymer layer selected
from the group consisting of: polyvinyl chloride (PVC),
PVC/vinyl copolymers, low and high density polyethylene,
polyethylene/vinyl copolymers, polyethylvinyl acetate and
copolymers, polyethylene terpthalate and copolymers,
polypropylene, polyamide, polyimide, polyurethane,
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polyvinylidene fluoride, fluorinated ethylene proplyene
polymers, polytetrafluoroethylene, silicone rubber, butyl
rubber, neoprene rubber, isoprene rubber, cellulose acetate
and laminated (co-extruded) membrane types (eg. PVC/fluori-
nated ethylene propylene polymers, polyethylene/ethylvinyl
acetate, polyethylene/polyethylene terpthalate and the
like). Different semiochemicals will have different
permeabilities with respect to the membrane used and this
provides versatility in attaining various desired release
rate characteristics.
In a further embodiment, the reactive urethane
mixture can be cast in a semiochemical permeable polymeric
tube. The tubing containing the urethane mixture and the
semiochemical can be used as long cylinders or cut into
short cylinders which serve as semiochemical dispensers.
In a broad aspect, the invention is directed to
a composite polymer semiochemical controlled release rate
dispenser comprising: (a) a polyurethane reservoir formed
from a reaction mixture of a polyol, a polymeric isocyanate
and an unreactive semiochemical compatible with the polyol
and isocyanate reaction mixture; and (b) a semiochemical
permeable polymeric membrane that covers at least part of
the reservoir, and which regulates the release of the
semiochemical from the dispenser.
The invention in another aspect pertains to a
composite polymer semiochemical controlled release dis-
penser comprising: (a) a polyurethane reservoir formed from
a reaction mixture of (i) a polyol selected from the group
consisting of hydroxy-terminated polybutadiene resins,
hydroxy-terminated polyether resins and hydroxy-terminated
polyester resins, (ii) an isocyanate component selected
from the group consisting of monomeric or polymeric
diphenylmethane diisocyanate, toluene diisocyanate,
isophorone diisocyanate, hexamethylene diisocyanate and
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polymeric hexamethylene diisocyanate, (iii) an unreactive
semiochemical(s) having functional groups selected selected
from the group consisting of alkanes, alkenes, alkynes,
aromatic hydrocarbons, ethers, esters, epoxides, aldehydes,
ketones, lactones, nitriles, imines, tertiary amines,
thioethers, sulfoxides, sulfones, disulfide compounds,
thioesters, organohalides, and mixtures thereof; and (b) a
semiochemical permeable polymeric membrane covering at
least a portion of the said polyurethane reservoir and
controlling release of the semiochemical from the reser-
voir, the membrane being selected from the group consisting
of polyvinylchloride, polyvinylchloride/vinyl
copolymers, low and high density polyethylene,
polyethylene/vinyl copolymers, polyethylvinyl acetate and
copolymers, polyethylene terpthalate and copolymers,
polypropylene, polyamide, polyimide, polyurethane,
polyvinylidene fluoride, fluorinated ethylene propylene
polymers, polytetrafluoroethylene, silicone rubber, butyl
rubber, neoprene rubber, isoprene rubber, cellulose acetate
and laminated (co-extruded) membrane types including
polyvinylchloride/fluorinated ethylene propylene polymers,
polyethylene/ethylvinyl acetate, polyethylene/polyethylene
terpthalate.
The semiochemical active ingredient can be
selected from the group: E or Z-13-octadecenyl acetate, E
or Z-11-hexadecenal, E or Z-9-hexadecenal, hexadecanal, E
or Z-11 hexadecenyl acetate,E or Z-9-hexadecenyl acetate,
E or Z-11-tetradecenal, E or Z-9-tetradecenal,
tetradecanal, E or Z-11-tetradecenyl acetate, E or Z-9-
tetradecenyl acetate, E or Z-7-tetradecenyl acetate, E or
Z-5-tetradecenyl acetate, E or Z-4-tridecenyl acetate, E or
Z-9-dodecenyl acetate, E or Z-8 dodecenyl acetate, E or Z-
5-dodecenyl acetate, dodecenyl acetate, 11-dodecenyl
acetate, dodecyl acetate, E or Z-7-decenyl acetate, E or Z-
5-decenyl acetate, E or Z-3-decenyl acetate, Z or E,Z or E
3,13-octadecadienyl acetate, Z or E, Z or E 2,13-
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octadecdienyl acetate, Z,Z or E-7,11-hexadecadienyl acet-
ate, Z,E 9,12-tetradecadienyl acetate, E,E-8,10-
dodecadienyl acetate, Z,E 6,8-heneicosadien-11-one, E,E
7,9-heneicosadien-11-one, Z-6-henicosen-11-one, 7,8-epoxy-
2-methyloctadecane, 2-methyl-7-octadecene, 7,8-
epoxyoctadecane, Z,Z,Z-1,3,6,9-nonadecatetraene, 5,11-
dimethylheptadecane, 2,5-dimethylheptadecane, 6-ethyl-2,3-
dihydro-2-methyl-4H-pyran-4-one, methyl jasmonate, alpha-
pinene, beta-pinene, terpinolene, limonene, 3-carene, p-
cymene, heptane, ethyl crotonate, myrcene, verbenene,
camphene, camphor, cineol, alpha-cubebene, allyl anisole,
undecanal, nonanal, heptanal, E-2-hexenal, E-3-hexenal,
hexanal, verbenone, 3-methyl-2-cyclohexenone, 3-methyl-3-
cyclohexenone, frontalin, exo and endo-brevicomin,
lineatin, multistriatin, chalcogran, 7-methyl-1,6-
dioxaspiro [4 . 5] decane, 4, 8-dimethyl-4 (E) , 8 (E) -
decadienolide,ll-methyl-3(Z)-undecenolide,Z-3-dodecen-11-
olide, Z,Z-3,6-dodecen-11-olide, Z-5-tetradecen-13-olide,
Z,Z-5,8-tetradecen-13-olide, Z-14-methyl-8-hexadecenal,
4,8-dimethyldecanal, gamma-caprolactone, hexyl acetate, E-
2-hexenyl acetate, butyl-2-methylbutanoate, propyl-
hexanoate, hexylpropanoate, butylhexanoate, hexylbutanoate,
butyl butyrate, E-crotylbutyrate, Z-9-tricosene, methyl
eugenol, alpha-ionone, 4-(p-hydroxyphenyl)-2-butanone
acetate, E-beta-farnasene, nepetalactone, 3-methyl-6-
isopropenyl-9-decenyl acetate, Z-3-methyl-6-isopropenyl-
3,9-decadienyl acetate, E or Z-3,7-dimethyl-2,7-
octadecadienyl propionate, 3-methylene-7-methyl-7-octenyl
propionate, 2,6-dimethyl-1,5-heptadien-3-of acetate, 2-2,2-
dimethyl-3-isopropenylcyclobutanemethanol acetate, E-6-
isopropyl-3,9-dimethyl-5,8-decadienyl acetate, Z-5-(1-
decenyl)dihydro-2(3H)-furanone, 2-phenethylpropionate,
3,11-dimethyl-2-nonacosanone, 8-methylene-5-(1-
methylethyl)spiro[11-oxabicyclo[8.1.0]undecene-2,2-oxiran]-
3-one, 2-propylthietane, 3-propyl-1,2-dithiolane, 3,3-
dimethyl-1,2-dithiolane, 2,2-dimethylthietane, E or Z-
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2,4,5-trimethylthiazoline, 2-sec-butyl-2-thiazoline,
isopentenyl methyl sulfide.
The active ingredient in composite polymer
release devices can be an unnatural synthetic behavior-
modifying chemical (semiochemical mimic) as defined above.
This group comprises chemicals not found in nature but that
cause behaviors that mimic those of a semiochemical.
The semiochemical concentration in the reservoir
of a composite polymer controlled release device can be
between 0.001% and 80o by weight. The reservoir forming
mixture can include substances selected from the group
consisting of antioxidants, ultraviolet light absorbers,
pigments, dyes, fillers, blowing agents and plasticizers.
The invention in a further aspect is directed to
a composite semiochemical controlled release rate dispenser
comprising: (a) a cylindrical polyurethane core formed from
a polyol, a diisocyanate and an unreactive semiochemical;
and (b) a semiochemical permeable rate controlling mem-
brane comprised of a dissimiliar polymeric tubing covering
at least a portion of the core.
DRAWINGS
In the drawings, which represent specific embodi-
ments of the invention, but which should not be regarded as
restricting the spirit or scope of the invention in any
way:
Figure 1 illustrate graphs which demonstrates
cumulative verbenone release from urethane monolithic
devices compared with identical urethane cores surrounded
by a permeable PVC membrane.
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Figure 2 illustrates a graph of average retained
Z-11-hexadecenal residue per device aged in a Florida
cotton field as a function over time. Figure 3 includes
similarly shaped PVC monolithic devices for comparison.
Figure 3 illustrates a plot of mean release rate
(mg/hour/device) of verbenone from composite polymer
release devices according to the invention, as a function
of time.
DETAILED DESCRIPTION OF THE INVENTION
The invention consists of versatile composite
polymer devices used for dispensing semiochemicals at a
controlled rate. Hydroxy-terminated polybutadiene resins
and/or other polyols an be combined with additives, semio-
chemical(s), and an isocyanate component to produce con-
trolled-release reservoirs. By varying the semiochemical
load, the cross-linking density of the matrix, the presence
of various resin additives, as well as the type of per-
meable membrane, a variety of release characteristics can
be obtained. Semiochemical dispensers can be produced
under very mild conditions using a simple process that is
readily adapted to automated production of a variety of
device forms. The main limitation of this method is that
the reaction chemistry which forms the device matrix is not
compatible with aqueous semiochemical mixtures and semio-
chemicals that have active hydrogen donating groups .
This technology is an improvement in several
aspects of semiochemical dispensers described in prior art.
The current technology may be conducted at room temperature
and this represents an energy saving over processes using
thermal curing (Fitzgerald et al. 1973 and Czechoslovakian
Patent No. 8490), melting polymers during semiochemical
loading (U.S. Patent Nos. 4,908,208 and 5,008,115) or
radiation curing methods (Kim et al. 1988 and Smith et al.
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1991). Moreover, since expensive volatile semiochemicals
may be lost during thermal processing, the current technol-
ogy offers further advantages over this type of prior art.
The invention allows the formation of a semio-
chemical reservoir in a single step at room temperature.
This contrasts strongly with U.S. Patent Nos. 4,908,208 and
5,008,115 which disclose silicone urethane copolymers which
first must be synthesized using inert atmosphere and high
temperatures, solvents removed, the copolymer melted and
mixed with the with active agent and hot viscous mixture
cast into devices. Other prior art membrane bound con-
trolled release devices such as those disclosed in U.S.
Patent No. 4,445,641 also require multiple processing
steps. Clearly, the devices specified in the current
invention are prepared by a much simpler process.
Other differences between U.S. Patent Nos.
4,908,208 and 5,008,115 and the current technology are also
evident. The subject invention discloses a thermoset
polyurethane semiochemical reservoir composed predominately
of soft block segments. Prior art silicone urethane
copolymers are thermoplastic which require both hard and
soft block segments in order to function properly as a
controlled release matrix. The urethane component of the
copolymers disclosed by Lee and Gornowicz consists of hard
block segments derived from short chain polyols and
diisocyanates while the soft block component of the are
derived from polydiorganosilane and or polyalkylene oxide.
Similar silicone urethane copolymers are disclosed as
membrane material in U.S. Patent No. 4,793,555 for the
release of aqueous mixtures and this is obviously outside
the scope of the subject invention.
Data is presented in U.S. Patent Nos. 4,908,208
and 5,008,115 that would indicate the practical utility of
devices prepared with some of these copolymer active
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ingredient combinations would be very limited. For
example, the release rate data presented in Table II (col.
8 and 9) for active agents in various copolymers is pres-
ented as a single value, implying a constant release (zero
order kinetics). This is misleading as release kinetics of
monolithic devices are known to be logarithmic. Close
inspection of release rate data given in Table II (col. 8
and 9) show that 20% trimedlure in copolymer I, 70%
trimedlure in copolymer II and 20% glossyplure have release
rates higher than the neat chemical. This data appears to
be erroneous since it is impossible for inert polymers to
increase the vapour pressure of a substance. More import-
antly, in controlled release applications, the objective is
to reduce the release rate from that of the neat chemical
to provide sustained release over long periods of time.
Obviously these copolymer matricies, at the stated
loadings, are not controlling the release of volatile
active agents. Similiarly, syneresis is observed with 900
trimedlure in copolymer II (example 5) and 33% benzyl
alcohol in copolymer II. This syneresis is an indication
of insolubility of volatile agents with the copolymer at
this loading level and is a serious dissadvantage in the
storage and use of such devices. Clearly, some of these
copolymer mixtures appear to be poor release rate regula-
tors for trimedlure, glossyplure and benzyl alcohol. The
shortcomings of this technology has limited the use of the
devices in semiochemical applications.
The invention is an improvement over prior art
monolithic silicone polyurethane copolymer or urethane
matrices (U.S. Patent Nos. 4,908,208, 5,008,115 and
4,594,380). These patents disclose matrix compositions but
do not mention nor demonstrate the use of release rate
controlling membranes in conjunction with the matrix. In
addition, none of these prior art patents indicate that the
release rate of any given active agent may be manipulated
by changes to the matrix and or the rate controlling
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membrane. The new composite devices of the invention
comprise polyurethane reservoir systems bounded by a
dissimiliar polymer which acts as a rate controlling
membrane. In addition to regulating the release rate, the
membrane of the composite devices has further advantages
over monolithic devices since it also serves to screen out
ultraviolet light and limit exposure to oxygen, both of
which may contribute to semiochemical degradation in the
matrix.
An example given by Chapin et al. in U.S. Patent
No. 4,594,380 demonstrates the effect of an open container
on the release of vapona. This example specifies a mono-
lithic wafer supported in container of unknown composition
and geometry with a 950 mm2 opening. There is no permeable
membrane to regulate the release characteristics. Further-
more, Chapin et al. at lines 21-27 of column 1, state:
"One class of methods comprises dispersion of the active
agent throughout (or dissolution in) a substantially inert
matrix from which the active agent is gradually released
into the environment. The discussion herein will be
limited to controlled-release methods of this type, and to
devices using this method. Such devices are frequently
referred to as 'monolithic' devices." U.S. Patent No.
4,594,380 therefore pertains to a homogenous, single compo-
nent (monolithic) device. Clearly, Chapin et al. did not
anticipate composite polymer devices using a semi-permeable
enveloping membrane of a seperate polymer to regulate the
release characteristics.
The teachings of U.S. Patent No. 4,594,380 are
predominately directed to the delivery of toxic agents. It
not obvious from these teachings that for many
semiochemical uses a very precise delivery of active agent
is necessary. U.S. Patent No. 4,594,380 does not teach
that the reactive nature of the urethane curing process may
be useful for removal of inhibitors from a semiochemical
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blend. In addition, no biological or field data demon-
strating efficacy was presented by Chapin et al.
The invention has addressed several of the
problems inherent in monolithic semiochemical release
devices and other prior art devices. The new technology
demonstrates that both the reservoir matrix and the device
membrane may be membrane may be manipulated. This compli-
mentary combination allows the composite polymer devices
better controlled release of semiochemicals than can
usually be attained using monolithic devices. Comparisons
of the new devices and prior art monolithic dispensers are
shown in Examples 1, 3 and 4.
Although the invention as described is not suited
to the release of aqueous semiochemical mixtures and
semiochemicals with active hydrogen donating groups, this
reactivity can be used to purify relatively crude semio-
chemicals in situ. Impurities of this nature can be
trapped by chemical reaction with the isocyanate component
during curing of the matrix. This method avoids the need
for additional purification of semiochemicals containing
low concentrations of impurities with hydroxyl, carboxyl,
sulfhydryl and amino functional groups. Example 2 demon
strates this principal.
The physical form of the subject invention can be
highly variable. For example, fillers or blowing agents
may be included in the formulation to produce a reservoir
where a high surface area is desired. Additives may be
used to absorb or reflect radiation (pigments, ultraviolet
screening agents and carbon black), inhibit oxidation
(antioxidants), to increase or decrease the viscosity of
the mix and or the release rate of the semiochemical
(plasticizers). Devices may be prepared by casting the
reactive mixture in polymeric tubing or molds containing
the polymer membrane. Layered or laminated devices may
CA 02218157 1997-10-10
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also be produced by casting the polyurethane reservoir on
various barrier materials or membranes. For example a
three layer laminate device might consist of an aluminum
foil barrier, polyurethane layer containing the AI and a
polyethylene membrane.
Hydroxy-terminated polybutadiene (poly BDTM)
resins with a range of hydroxyl numbers and molecular
weights are available and are preferred components in
polymerizing the matrix. Those available from Atochem
North America include the following poly BDTM resins: R45M
(average molecular weight 2800 and hydroxyl value 0.73
meq/g), R45HT (average molecular weight 2800 and hydroxyl
value 0.83 meq/g), R20LM (average molecular weight 1200 and
hydroxyl value 1.7 meq/g), and 605 (an epoxidized hydroxyl-
terminated polybutadiene with an oxirane content of 6.5% by
weight and hydroxyl value of 2.7 meq/g) . Poly BDTM resins
alone or blended with polyether or polyester polyols are
compatible with many classes of semiochemicals. Variation
of the mixtures may be used to change the solubility
parameter, hydrogen bonding and the extent of cross linking
within the matrix by methods known in prior art.
U.S. Patent No. 4,594,380 has indicated the use
of hydroxy or carboxy-terminated copolymers of butadiene
and acrylonitrile or styrene as agents to modify a poly BDTM
based urethane release matrix. These materials are of high
viscosity and are not easily incorporated into the matrix
without considerable heating and the use of specialized
mechanical mixing equipment. Of far more utility are low
viscosity hydroxy-terminated polyethers which may be used
to modify the release matrix. Examples of low viscosity
polyether polyols compatible with poly BDTM resins include
polymers of polyproplene glycol such as PluracolTM 220
(hydroxyl number 27), PluracolTM 2010 (molecular weight
2000, hydroxyl number 56) both available from BASF Corpor-
CA 02218157 1997-10-10
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ation, and AlkapolTM G-240 (molecular weight 700, hydroxyl
number 240) available from Rhone-Poulanc Speciality Chemi-
cals, Mississauga, Ontario). Similar materials are avail-
able from several other manufacturers. The polyol compo-
nent can also include materials to enhance the
biodegradability of the matrix for example polycaprolactone
diol or carbohydrate-based materials (cellulose esters and
ethers ) .
Semiochemical controlled release device reser-
voirs prepared with a high proportions of hydroxyterminated
butadienes will be highly elastic and will consist of
predominately of soft block domains. The isocyanate
component is generally an MDI with LupranateTM MM-103
(isocyanate content 29.50 by weight available from BASF
Corporation) and IsonateTM 143L (70-80o MDI and 20-30%
polymerized MDI, available from Dow Chemical U.S.A.) as
examples of suitable commercially available materials.
Other isocyanates including toluene diisocyanate,
isophorone, diisocyanate and hexamethylene diisocyanate as
well as other MDI blends can also be used in the process.
The process generally requires no catalysis, however,
catalysts known from prior art may be used with some of the
slower reacting isocyanate/polyol combinations. Since
isocyanates react readily with water, precautions must be
taken to insure that the semiochemical, polyol and other
matrix additives used are substantially free of water.
The general method for preparation of the
polyurethane reservoir is based on the "one shot" batch
protocol outlined for the reaction of poly BDTM resins with
MDI (Ryan 1971). Typical preparation of a semiochemical
reservoir involves warming the polyol component and addi-
tives to 35-75° C with stirring at a vacuum of 15-100 mm to
remove traces of volatile contaminants. The vessel is
returned to ambient temperature and pressure and the
semiochemical (0-80o w/w) is added to the mix. The mixture
CA 02218157 1997-10-10
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is stirred under vacuum until homogeneous. The isocyanate
component added (isocyanate index 1.05) and stirring under
vacuum continued. The mixture is transferred to molds and
left to polymerize. The time for polymerization can vary
from a few minutes to several days and is accelerated by
catalytic means or by curing at higher temperatures.
The polymeric matrix used for the reservoir is
compatible with a large number of semiochemicals. The
skilled practitioner will be aware that hundreds of semio-
chemicals are known and complete listing of compounds
compatible with the matrix is clearly impractical. Some
examples demonstrating the range of active ingredients
suited to incorporation into the composite polymer devices
include: lepidopteran pheromones (E or Z-13-octadecenyl
acetate, E or Z-11-hexadecenal, E or Z-9-hexadecenal,
hexadecanal, E or Z-11 hexadecenyl acetate,E or Z-9-
hexadecenyl acetate, E or Z-11-tetradecenal, E or Z-9-
tetradecenal, tetradecanal, E or Z-11-tetradecenyl acetate,
E or Z-9-tetradecenyl acetate, E or Z-7-tetradecenyl
acetate, E or Z-5-tetradecenyl acetate, E or Z-4-tridecenyl
acetate, E or Z-9-dodecenyl acetate, E or Z-8 dodecenyl
acetate, E or Z-5-dodecenyl acetate, dodecenyl acetate, 11-
dodecenyl acetate, dodecyl acetate, E or Z-7-decenyl
acetate, E or Z-5-decenyl acetate, E or Z-3-decenyl acet-
ate, Z or E,Z or E 3,13-octadecadienyl acetate, Z or E, Z
or E-2,13 octadecadienyl acetate, Z,Z or E-7,11-
hexadecadienyl acetate, Z,E 9,12-tetradecadienyl acetate,
E,E-8,10-dodecadienyl acetate, Z,E-6,8-heneicosadien-11-
one, E,E 7,9-heneicosadien-11-one, Z-6-henicosen-11-one,
7,8-epoxy-2-methyloctadecane, 2-methyl-7-octadecene, 7,8-
epoxyoctadecane, Z,Z,Z-1,3,6,9-nonadecatetraene, 5,11-
dimethylheptadecane, 2,5-dimethylheptadecane, 6-ethyl-2,3-
dihydro-2-methyl-4H-pyran-4-one, methyl jasmonate), bark
beetle kairomones (alpha-pinene, beta-pinene, terpinolene,
limonene, 3-carene, p-cymene, myrcene, verbenene, camphene,
camphor, cineol, alpha-cubebene, allyl anisole, undecanal,
CA 02218157 1997-10-10
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nonanal, heptanal, E-2-hexenal, E-3-hexenal, hexanal,
heptane, ethyl crotonate), bark beetle pheromones
(verbenone, 3-methyl-2-cyclohexenone, 3-methyl-3-
cyclohexenone, frontalin, exo and endo-brevicomin,
lineatin, multistriatin, chalcogran, 7-methyl-1,6-
dioxaspiro[4.5]decane), grain beetle pheromones (4,8-
dimethyl-4(E),8(E)-decadienolide, 11-methyl-3(Z)-
undecenolide, Z-3-dodecen-11-olide, Z,Z-3,6-dodecen-11-
olide, Z-5-tetradecen-13-olide, Z,Z-5,8-tetradecen-13-
olide), dermestid and tenebrionid beetle pheromones (Z-14-
methyl-8-hexadecenal, 4,8-dimethyldecanal, gamma-
caprolactone), apple maggot kairomones (hexyl acetate, E-2-
hexenyl acetate, butyl-2-methylbutanoate, propylhexanoate,
hexylpropanoate, butylhexanoate, hexylbutanoate), dipteran
pheromones and synthetic attractants (Z-9-tricosene, tert-
butyl-4 (or 5)-chloro-2-methyl-cyclohexanecarboxylate,
methyl eugenol, alpha-ionone, 4-(p-hydroxyphenyl)-2-
butanone acetate), aphid pheromones (E-beta-farnasene,
nepetalactone), hemipteran pheromones (butylbutryate and E-
crotylbutryate), homopteran pheromones (3-methyl-6-
isopropenyl-9-decenyl acetate, Z-3-methyl-6-isopropenyl-
3,9-decadienyl acetate, E or Z-3,7-dimethyl-2,7-
octadecadienyl propionate, 3-methylene-7-methyl-7-octenyl
propionate, 2,6-dimethyl-1,5-heptadien-3-of acetate, 2-2,2-
dimethyl-3-isopropenylcyclobutanemethanol acetate, E-6-
isopropyl-3,9-dimethyl-5,8-decadienyl acetate), Japanese
beetle pheromone and attractants( Z-5-(1-decenyl)dihydro-
2(3H)-furanone, 2-phenethylpropionate), cockroach
pheromones (3,11-dimethyl-2-nonacosanone,8-methylene-5-(1-
methylethyl)spiro[11-oxabicyclo[8.1.0]undecene-2,2-oxiran]-
3-one), mammal predator kairomones (2-propylthietane, 3-
propyl-1,2-dithiolane, 3,3-dimethyl-1,2-dithiolane, 2,2-
dimethylthietane, E or Z-2,4,5-trimethylthiazoline, 2-sec-
butyl-2-thiazoline, isopentenyl methyl sulfide). It should
be noted that some semiochemicals such as 2,4,5-
trimethylthiazoline (with an imine functionality) or
tertiary amines, although not reactive (compatible) with
CA 02218157 1997-10-10
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the matrix, will act as catalytic agents in the
polyurethane forming reaction. These materials are not
well suited to the batch method on a large scale, but are
easily incorporated in a reaction injection moulding (RIM)
process to produce devices.
The presence of a permeable polymer membrane on
the dispensers is significant feature of this technology.
There are a great number of polymer membrane types commer-
cially available. With this large selection, membrane
materials can range from almost impermeable to highly
permeable for most semiochemicals. It is recognized that
the optimal release rate characteristics will be attained
when the membrane material is not a polyurethane composed
predominately of hydroxy-terminated polybutadiene. The
membrane material may be selected from polyvinyl chloride,
PVC/vinyl copolymers, low and high density polyethylene,
polyethylene/vinyl copolymers,polyethylvinyl acetate and
copolymers, polyethylene terpthalate and copolymers,
polypropylene, polyamide, polyimide, polyurethane,
polyvinylidene fluoride, fluorinated ethylene proplyene
polymers, polytetrafluoroethylene, silicone rubber, butyl
rubber, neoprene rubber, isoprene rubber, cellulose acetate
and laminated (co-extruded) membrane types (eg. polyvinyl-
chloride/fluorinated ethylene propylene polymers,
polyethylene/ethylvinyl acetate, polyethylene/polyethylene
terpthalate and the like).
The composite polymer devices exhibit a charac-
teristic release of semiochemical over time as demonstrated
in Examples 1,3, and 5. After manufacture devices are
usually stored in vapour tight containers until the dis-
pensers are needed. During this time the semiochemical
approaches equilibrium concentrations in the matrix, the
surrounding membrane and the atmosphere within the storage
container (based on the solubility of the semiochemical in
these various media). When these dispensers are removed
CA 02218157 1997-10-10
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from storage they will exhibit a moderate to sharp decline
in release rate as the semiochemical evaporates from the
surface of the device. This drop in release rate takes
place over several hours or weeks and depends upon environ-
s mental conditions, the volatility of the semiochemical and
the type of matrix and membrane combination. Once diffu-
sion of the semiochemical from the matrix to the surface of
the membrane has taken place the dispensers will release at
more constant levels for prolonged periods. This period of
relatively higher release has not hampered the use of these
devices in dispensing anti-aggregation pheromones for tree
protection or predator kairomones for mammal repellent
applications or sex pheromones for mating disruption
applications. When dispensers are produced for monitoring
traps, they may be removed from storage and "pre-aged"
prior to field deployment or the traps simply set out an
appropriate time earlier than the anticipated flight of the
pest.
A single manufacturing method may be used to
produce several different types of release devices using
the current invention, exemplified by the casting of the
urethane matrix in PVC tubing. Short pieces of tubing
(0.2-10.0 cm) can be cut and distributed for ground-based
semiochemical dispensers in repellent or mating disruption
applications. Similarly, short pieces of the tubing serve
as single point source semiochemical emitters used as lures
in insect traps. Where point source emitters are not
desired, long lengths of semiochemical loaded tubing may be
used. For example several meters of loaded tubing may be
attached to a tree to provide semiochemical release over a
large area. Long lengths of semiochemical-loaded tubing
have advantages over devices with small reservoirs in that
semiochemical release is possible for extended periods of
time. The new technology is capable of producing devices
that control the release of AI from minute quantities
CA 02218157 1997-10-10
- 23 -
(ng/day) to a release hundreds of milligrams or even grams
of AI per day.
EXAMPLE 1
This example show two similiar but separate
experiments demonstrating the effect of a membrane on the
release characteristics of the bark beetle anti-aggregation
pheromone verbenone from a polyurethane matrix. In these
experiments, the matrix was prepared via the basic method
outlined that contain verbenone (active ingredient) and a
polyurethane composed of poly BDTM R45HT and LupranateTM
MM103. The matrix mixture was divided and used to prepare
both composite polymer devices and homogenous monolithic
devices in both experiments.
In the first experiment (series A), a mixture
containing 9.86% verbenone is allowed to polymerize in PVC
tubing (0.5 mm thick and 3.8 mm i.d.) for 16 hours at room
temperature in a sealed polyethlene nylon laminate bag.
The tubing is cut into 10 cm lengths and in one group of
devices, the outer PVC membrane is carefully removed to
produce monolithic devices. Each device core contained a
calculated load of approximately 100 mg of verbenone.
In the second experiment (series B), a mixture
containing 8.96% verbenone is allowed to polymerize in: 1)
PVC tubing ( 0 . 5 mm thick and 3 . 0 mm i . d. ) which was heat
sealed every 10 cm along its length 2) glass tubing 50 cm
long x 3.0 mm i.d. capped at both ends with a rubber septa.
The loaded tubes were left at room temperature in a sealed
polyethylene/nylon laminate bag for one week. The loaded
PVC tubing was cut every 10 cm at centre of the heat seal
to provide composite polymer devices (a urethane core
completely surrounded by a permeable PVC membrane). The
glass tubes were carefully broken and the resulting
urethane rod was cut into 10 cm lengths to provide mono-
CA 02218157 1997-10-10
- 24 -
lithic (unsheathed) devices. Each device core contained a
calculated load of approximately 78 mg of verbenone.
In both experiments, four replicates of the
composite polymer devices and four monolithic devices were
aged in a temperature controlled environment chamber at 30°
for the A series (first experiment) or at 35°C for the B
series (second experiment) with an air flow through the
chamber at a rate of 15 cfm. Devices were weighed at
regular intervals on a balance with a precision of 0.05 mg.
The average cumulative percentage weight loss per device
was plotted against time for the first experiment is shown
in Figure 1, A series and the second experiment is shown in
Figure 1, B series.
In both experiments, the effect of the permeable
polymer membrane was dramatic, the monolithic devices A and
B rapidly lost verbenone such that 50-70 % was evaporated
in the first 2-3 days. In contrast, the composite polymer
devices A and B released verbenone relatively smoothly
throughout the test period. After 30 days the monolithic
devices had released approximately 85% of the loaded
verbenone while the composite devices had released 14-22
of the loaded verbenone. In addition, as demonstrated by
the smooth curves, the rate of verbenone release from the
composite devices was much more constant than that of the
monolithic devices. The composite polymer devices, both A
and B, in these experiment were clearly superior in the
controlled release of verbenone to the environment over
long periods of time.
The two experiments show the similarities between
the monolithic devices A and B or the composite devices A
and B at both 30°C and 35°C. There is not much difference
between the composite devices A or B. Likewise, the curves
for the monolithic devices A and B substancially overlap.
CA 02218157 1997-10-10
- 25 -
The curves shown in Figure 1 also demonstrate the
permeability of the PVC membrane to verbenone. In the
second experiment the composite polymer devices were
completely enclosed in the PVC membrane, while in the first
experiments the composite polymer devices were open-ended
cylinders. In both experiments the effect of the PVC
polymer membrane was very clear when compared to the
monolithic devices. The release characteristics of both
types of composite polymer devices A and B are similar, the
effects of the open ends is minimal, even at different
temperatures, in comparison to the absence of the membrane.
Furthermore, the effects of the open ends is minimized when
the geometry of the device is a cylinder many times longer
than it is in diameter, as was the case in these experi
ments.
EXAMPLE 2
This experiment demonstrates the capability of
the reservoir forming reaction to purify a crude semio-
chemical mixture in situ during the curing process. The
main component in the pheromone of Choristoneura fumiferana
is E-11-tetradecenal together with a small percentage of
the Z isomer (Silk et al. 1980). The insect response to
this pheromone blend is inhibited by E-11-tetradecenol
(Sanders 1972) which is often the synthetic precursor to
the aldehyde and may be present as a contaminant in some
batches of pheromone. A mixture of 34.2 mg of E-11-
tetradecenal (92.5% E isomer, 5.3% Z isomer, free of
detectable alcohols) and 4.7 mg of E-11-tetradecenol (990
pure) was prepared and a sample subjected to capillary gas
chromatography (GC). Under the conditions used, the ratio
of peak areas of E-11-tetradecenol to E-11-tetradecenal was
0.1322. Another sample of the aldehyde/alcohol mixture
(approximately 2.0% w/w) was polymerized with 20% w/w of
dioctyladipate and poly BDTM R45HT and LupranateTM MM 103
(isocyanate index 1.1). After polymerization the resulting
CA 02218157 1997-10-10
- 26 -
plug was loosened from the vial walls and extracted with
five volumes of hexanes overnight. A sample of the extract
was diluted six fold and subjected again to GC analysis.
After this analysis the ratio of peak areas of E-11-
tetradecenol to E-11-tetradecenal was now 0.0049. The
results demonstrate that approximately 96% of the original
E-11-tetradecenol had been removed during the curing
process. This example also serves to demonstrate why
semiochemicals with active hydrogen donating groups are not
compatible with this type of polyurethane reservoir.
EXAMPLE 3
This example demonstrates that the composite
polymer devices have sustained release capabilities for a
labile lepidopteran pheromone. The new dispensers are
compared with prior art monolithic devices. A polymeric
core formulated from poly BDTM R45HT, IsonateTMTM 143 L,
14.50 dioctyladipate w/w and 1.37 % Z-11-hexadecenal w/w
as the active ingredient AI was cast into PVC tubing 4.8 mm
diameter with 0.5 mm wall thickness. Cylinders 42 mm long
were cut from the tubing to form the devices used in this
test. Devices were tethered to cotton plants and exposed
to ambient conditions in Florida during August - October
1991. Sample devices were collected at weekly intervals,
sealed in nylon polyethylene laminate bags and stored at 5°
C or lower until analysis. Samples consisting of three
devices were repeatedly extracted with hexanes, the
extracts were pooled, treated with Hexadecane as an inter-
nal standard and analyzed by capillary column gas chroma-
tography. The extracts were analyzed for AI and Z-11-
Hexadecenoic acid, an expected oxidation product of the AI.
The results of the residue analysis are graphed as a
function over time in Figure 2. Results from similarly
shaped PVC monolithic devices are included for comparison
in Figure 2. Clearly, the composite polymer devices have
superior controlled release properties when compared to the
CA 02218157 1997-10-10
- 27 -
monolithic devices. The results demonstrate that the
composite polymer device affords some protection of the
pheromone from oxidation. Except for an initial sharp drop
in the residue weights in the first two weeks, the devices
exhibit a smooth release of AI for over 60 days under
relatively high temperature field conditions. Such a
device is potentially useful for mating disruption of
Heliocoverpa (Heliothis) species.
EXAMPLE 4
In this example, composite polymer lures were
compared with two types of monolithic PVC lures in sticky
traps. The biological assay was conducted at sites in
Oregon, Washington, California and Idaho in 1991. The
devices were 4 mm diameter with a wall thickness of 0.5 mm
with a core composition containing poly BDTM R45HT,
IsonateTM 143L, 50% w/w dioctyladipate and 0.001 % w/w of Z-
6-Henicosen-11-one as AI. The PVC devices were 5 mm long
and the urethane cored devices were 8 mm long, with all
devices containing equivalent weights (approximately 500 ng
each) of AI. The results of this test are shown in Table
1.
CA 02218157 1997-10-10
- 28 -
TABLE 1: Summary of Douglas-~r tussock moth lure evaluation.
Lure Type PVC 1 PVC 2 CON~OSITE
# of sites (4 blocks/site)27 27 27
Sum of avg # insects 414.92 596.00 685.83
trapped/block
Avg # insects trapped/block15.37 22.07 25.40
Standard Deviation 23.63 23.71 24.66
1 Maximum # trapped/block 87.50 81.75 75.75
o
The results demonstrate that composite polymer
devices show good biological activity and no inhibitors of
the biological response were present. These devices are
useful as an early warning monitoring tool for detecting
Douglas-Fir tussock moth populations.
EXAMPLE 5
In this example two different urethane
semiochemical blends were cast into lengths of ethylvinyl
acetate / ethylene copolymer tube stock 12 micron thick to
produce pouches 5.2 x 10.0 cm. After loading with semio-
chemical and polymer, the packages were heat sealed and
allowed to polymerize. The composite polymer devices were
made to contain 5.0 g each of verbenone as the semio-
chemical. Sample A devices contained 80o verbenone w/w and
20o polyurethane prepared from poly BDTM R45-HT and
LupranateTM MM-103. Sample B devices contained 20%
verbenone w/w and 80o polyurethane prepared from poly BDTM
R20LM and lupranate~ MM-103. The devices were aged in a
CA 02218157 1997-10-10
- 29 -
temperature controlled chamber at 24° C with a flow of air
through the chamber of 15 cfm. Release rate of semio-
chemical from the controlled devices was determined by
weight loss. The observed mean release of verbenone from
these devices over time is shown in Figure 3. The results
demonstrate that resin type and pheromone load can substan-
tially alter the release rate characteristics of these
devices. Devices such as these are useful for dispensing
anti-aggregation pheromones of bark beetles.
EXAMPLE 6
Many different composite polymer devices have
been used to deliver semiochemicals under conditions of
actual field use. The type of membranes used has included
polyvinyl chloride, PVC/vinyl copolymers, low and high
density polyethylene, polypropylene, nylon,
polyethylene/vinyl copolymers, polyethylvinyl acetate and
copolymers, polypropylene, nylon (polyamide), and laminated
(coextruded) polyethylene/nylon. The types of semio-
chemicals has included: Z-11-hexadecenal, Z-9-hexadecenal,
E-11-tetradecenal, Z-9-tetradecenal, E or Z-11-
tetradecenyl acetate, E and Z-9-dodecenyl acetate, Z-7-
decenylacetate, Z,E 9,12-tetradecadienyl acetate, Z,E 6,8-
heneicosadien-11-one, E,E 7,9-heneicosadien-11-one, Z-6-
henicosen-11-one,7,8-epoxy-2-methyloctadecane,2-methyl-7-
octadecene, 7,8-epoxyoctadecane, alpha-pinene, terpinolene,
limonene, 3-carene, p-cymene, heptane, allyl anisole,
undecanal, nonanal, hexanal, verbenone, frontalin, exo-
brevicomin, conophthorin (7-methyl-1,6-
dioxaspiro[4.5]decane), Z-14-methyl-8-hexadecenal, hexyl
acetate, E-2-hexenyl acetate, butyl-2-methylbutanoate,
propylhexanoate, hexylpropanoate, butylhexanoate,
hexylbutanoate), butylbutrate, E-crotylbutyrate, 2-9-
tricosene, 2-propylthietane, 3-propyl-1,2-dithiolane, 2,2-
dimethylthietane, E and Z-2,4,5-trimethylthiazoline, and
isopentenyl methyl sulfide).
CA 02218157 1997-10-10
- 30 -
As will be apparent to those skilled in the art
in the light of the foregoing disclosure, many alterations
and modifications are possible in the practice of this
invention without departing from the spirit or scope
thereof. Accordingly, the scope of this invention is to be
construed in accordance with the substance defined by the
following claims.
CA 02218157 1997-10-10
- 3~ -
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Arn H., et al., ed. 1992: "List of Sex Pheromones of
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Budavari, S., ed. 1989: "The Merck Index", 11th edition,
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Cunningham, R.T., et al. 1990: "The Male Lures of Tephritid
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Ridgway R.L., et al. ed. 1990: "Behaviour Modifying Chemi-
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