Note: Descriptions are shown in the official language in which they were submitted.
~0~439~ .
B~CI'GI~OUND OF 'rl-l~ :[NV]I~TION
. _ . ... . . __
~hile the invention is pxlmarily concerned with the
practical methods of insect control, never.the].ess tlle concepts
here involved are applicable to all uses of controlle(3 vapor
dispersion. ~lowever, sincc insect att1-actants a.re of major
importance, the descriptioll of the invention will bc clirected
to such a usage.
- That insec-ts can be attracted or repelled by certain
substances has been known ~or a great many years. In recent
years, efforts have been made to utilize and extend this prim-
itive kno~Yled~e for the purpose of controlling insect pests and
~; mitigating the harmful effects they can inflict on man, animals,
agricultural crops, clothing, Q~C. This has led to the recog--
nition that olfaction plays a key role in coï~nunication among
insects and that the media of communication are chemical sub-
stances produced and emitted by insects for communicative
purposes. These chemical messengers have come to be called
Y pheromones and are known to be highly specific as to insect ~ :
species and eli~ited response. Pheromones may serve as alarm
signals, food finding aids, mating signals, trail markers, ox
defensive agents for ward`ing of~ predators.
A gxeat many insect sex attractant pheromones have been
isolated and identified as to chemical composition and structure.
; They typically are straight chain or cyclic organic compounds of
` carbon, hydrogen, and oxygen, falling in the molecular weight
i~ range of 150 to 130. The structure and biological activity of
most o~ the known insect sex pheromones are extensively xevi.ewed
in the book, INSECT SEX PHERO~IONES, by Martin Jacobson, ~cademic
,,1,. .
''!
1! d~/~C~
, . . . -.... ~.. . . . .- . ~ , ... ... : -
`- 10~
Press, Ne~ York, 1~72. Of the idcntified insect sex pheromones,
many have been synthesized and the synthetic materials used in
a variety of ways to facilitate insect pest control.
Two general methods of employing insect sex pheromones
have been applied. One method involves using the pheromone to
attract a target insect to a trap or to a point where it can
be destroyed by an insecticide. Trapping also serves as a survey
means of timing the application of chemical insecticides. A
second method involves broadcasting small point sources of
pheromone over an infested area to disorient the insects and
make it difficult or impossi~le for the opposite sexes to find
one another for mating. This latter method is referred to as
the disruption technique, and is intended to suppress the pest
insect population by subverting or interrupting the natural
mating and reproduction process.
Effective and economical use of insect sex pheromones
for accomplishing insect pest control, by whatever strategy,
requires a suitable means of dissemination. A dissemination
method or device must accomplish dischaLge of the pheromone to
the atmosphere at a specific rate peculiar to the target insect,
and for whatever period of time the particular adult il?sects are
active in mating. Sin~e synthetic insect sex pheromones are
frequently rather expensive materials, the dissemination means
or devices must be as efficient as possible in utilization of
pheromone. Thus, a practical and economical sustained release
system must be employed for disseminating pheromone which pro-
vides for a controlled discharge of the attractant at a specified
rate and for a specified period of time.
. 1 '
dg/~ :c, - 4 -
- . ~ . . -
- ~., . - . . - .
- . . . .
~o~j,4~g~L
Nurnerous examples of sustained or controlled release
systems exist in the prior art of ins~ct pest control. United
States Patents, 2,956,073, 3,116,201, and 3,318,769 teach the
manufacture and use of insecticides formulated into shaped
plastic articles which serve to release the insecticide at a
prescribed rate over an extcnded period of time. U.S. Patent
3,539,~65 teaches the microencapsulation of hydrophilic liquid-
in-oil emulsions in which polymeric capsular walls serve to
mediate the controlled re].ease of ensapsulants such as insect-
icides and other biocidal agents. U.S. Patent 3,740,419 teaches
the use of insecticide impregnated wood chips as a slow release
pest control device. ~.S. Patent 3,577,515 teaches the manufac-
ture of microencapsulated insecticidal compositions by using
interfacial polymerization to form a porous capsule wall which
serves to regulate the rate of deli~ery of insecticide. U.S.
Patent 3,590,118 describes a slow release insect repellant
system in the form of a breathable acrylic film. U.S. Patent
3,592,910 discloses use of terpenoid resin-insecticide formu-
lations which are designed to extend the period of effectiveness
for.nonpersistent or moderately persistent insecticides. ~
Each of these methods has its own particular cluster
of advantages and drawbacks, wh.ich need not be elaborated here.
Rather it would be more in order to point out that researchers
and economic entomologists continue to seek a more satisfactory
scheme for the uniform, ~uantitatively predictable, prolonged
automatic dissemination of miniscule amounts of active volatiles
;~ at an extremely low controlled rate. Sometimes the dissemination
is de5ired on a tree-by~tree basis as, for example, in the
.
dg/~C~ S
. .. . . . ~. . . . . . : -.: .. : , ,, . ... .: . . : . : - -
; . . . .-. . - .: :.. .. -: ..
~ ~ , , . . .. , -- - . :: -, ., . : .. . , - . : , :
- . :
control of certain orchard pests. Sometimes the dissemination
is to be uniform and cover large areas, as in the use of phero-
mones to disrupt mating signals of insect pests attac]cing field
crops. One possible superior means of achieving these ends
entails the use of fine capillary tubes, both as containers '~
and discharge devices.
Several researchers have had more or less limited
success in the use of micro-tubes or micro-capillaries in labor-
atory tests and under limited experimental field conditions. We
have encountered, and indeed have other workers in this area,
several significant obstacles to the widespread practical'appIi-
cability of the conventional forms of these devices. We have
also discovered, however, a novel and superior variation of the
micro-tube dissemination method and device which overcomes these
obstac]es and provides an extremely useful manner of using fiber
tubes for the intended purpose in practical applications.
~.~
Previous users of micro-tubes'for pheromone delivery
have regularly employed them as containers and dispensers with
both ends of the tube open to the atmosphere. The rate of
pheromone discharged fr~m the ends of the micro-tubes or
micro-capillaries when u~ed this way has generally been exces-
... .
sively high for many practical field applications. Mor~over,when open at both ends such devices are subject to high material
losses due to mechanical shock, vibration, wind, and the like.
Our invention, which comprises the use of micro-tubes
or capillary channels of microconduits sealed at one end, whïle
exceedingly simple, eliminates several significant obstacles to
the'use of such devices and confers on them practicability to an
. . .
, dg/~3~`J -6-
-`" 106~3g~
extent not heretofore contempla-ted by those familiar with the
art.
As an example of the prior art, ~eference may be drawn
to the article, "NOVEL TRAPPING AN~ DELI~ERY SYSTEMS FOR AlRI~ORNE
INSECT Pt~EROMONES," by Lloyd E. Browne, et al, J. Insect ~
1974, Vol. 20 pp. 183 to 193. On Pages 187-188, a laboratory
testing scheme for assaying pheromone efficiency is described
- where the active liquid is fil]ed into a 5~1 glass capillary
mounted vertically and open at both ends. The contained liquid
is continuously evaporated from the liquid-air interface exposed
at the bottom of the capillary to which it continuously feeds
by the action of gravity While the delivery rate may be kept
quite co~lstant, it is also quite high, being of the order of
1 ~l/minute. The dimension of the capillary tube is about 5 cm
long by .4 mm diamet~r. A full charge of hexane will be dis-
- charged in about 5 mi.nutes in the test described.
Another example of the prior art using microtubes
is described by Shorey Q~ ~Q, in "SEX P~ERO~ONES 0~ LEPIVOPTERA.
XXX. ~ISRUPTZON OF SEX P~EROMONE COMMUNICATIONS IN 'TRlCliOPLASlA
Nl' AS A POSSIBLE MEANS OF MATING CONTROL," Environmental
Entomolog~, Vol. 1, No. 5, October 1972, pp. 641~645. Schemes
for evaporation of pheromones at lower, intermediate, and higher
rates are discussed. It should be noted that in this work the
- authors view the use of micro-tubes as part of the higher rate
technique.
"ThQ 4ub4 ~ha;~Q4 ~Oh hl~ghQh Q~JapO~La~On ha~tQ4 UJQJtQ
ba4Qd on ~hQ ph~nC~pQQ O~ a Q~qu~d ~em o~ ~hQ p~Q
chQm~coe bQ~ng Qxpo~Qd- ~ ~tQ a~. ThQ ha~Q ~a4
.` :
1- .
. . '
- ,. ... -. - , .. . ~ . : . .. .
10~4391
,_ .
vaJL~e~d by va~Ly~n~ ~hQ at~Qa a ~ QXpO~ Qd b~2m. rhQ~ Q
Qvapu~La;~v~Lb CU u~d bQ ~ Q~ ;t ~n ~ILQ ~Q~d ~o'L b QVQ~La~
dayb u)~huu~ a dQchQabQ ~n ~lQ~L tLe~QabQ ~La~Q~ In
p~Lac~LcQ> ho~evQ~L~ ~hQy ~Q~LQ bQ)LV~CQd and ~LQchatLgQd
da~Qy. ThQ 10 ng/n1~n Qvapu~a~uJL cc) n~ ;tcd o ~ an
0.3~ mm l~ TQ~Un ~ubQ, 20 mm ~ongj hQ~d vQ~L~ca~y
in a c~p a~achQd ~u ~h~ ~VOUdQn ~:akQ. LC~UP~U~LQ
u)ab hQ~d ~n ;thQ ~U~QtL Qnd c) ~, ;thQ ~ubQ b~ cap~at
An ~nVQ~L;~Qd a~um~num ~Q~gh~ng cup a*~achQd ~u ~hQ
~p o6 ~hQ ~al~Q ~a~ U~.Qd ~u bh~Q~d ~hQ *~bQ ~Lom
QXCQbb~VQ ~ndb, uJh~ch a~ ~mQ/6 ~UtLCQd ~hQ ~OOp~UtLQ
~u~ u6 un~h~Q~dQd ~ubQ~. ThQ 30 n9//h~rL Qvapa~a;~
conbi~Qd u~ 3 ~m~QatL TQS~Un ~bQb hQ~d ~n a ~n9QQ
~,e.,~,p. ~
~he dissemination principle of this scheme is the same as that
i from the previous citation: liquid continuously evaporates at
a liquid-air interface maintained by gravity at the bottom of
:.
, a double open-end vertical capillary tube. The particular
r dissemination rates for those materials~are at least an order
of magnitude higher and up to 3 orders of magnitude high~r than
can be achieved by the use of our invention. It will also be
noted that because of the double open-end configuration, tlle
tube contents are unstably retaine~ and subject to being blown
out by wind. Note, also, the requirement for daily attention.
Both of these objectionable situations are obviated by our device.
As a further example of the prior art, we may cite
Pitman and Vité, "FZELD RESPONSE OF ~EN~ROCTONUS PSEU~OSUGAE
(COLEOPTERA: SCOLYTIDAE) TO SYNTHETIC FRONTALlN,'i Annals of
3 The Entomological Society of ~merica, Vol. 63, No. 3, pp. 661-664,
~ May 1970, who used 0.4 mm ID glass capillary tubes for the
~o~43~
dissemination of synthetic frontalin. The release rate that
they experienced was 5 mg/hr. By the use of our invention,
with the same pheromone and approximately equivalent size
tubing, the rate was reduced by two to three orders f magnitude
(i.e.,` 100 to 1,000 times). As a result, the practical
feasibility of our scheme to long-term controlled dissemination
of minute amounts of this and other pheromone materials is
superior; so much so as to render our method a practical scheme
for commercial pest management, in contrast to the limited
experimental activities of the prior workers.
SUMMARY OF THE INVENTION
Accordingly, the basic purpose of this invention is to
provide an improved means of dissemination of vapors for several
purposes, such as, for example, pheromones and fragrant vapors,
in which the timing of the dissemination of the vapor can be
controlled and its duration extended by evaporation from an
occluded liquid-gas interface within the microconduit through
a stagnant boundary layer of evaporant at an interface with ;
the external atmosphere.
~ 20 In one particular aspect the present invention provides
a device for disseminatlon of a vaporizable substance at a
predetermined rate by vapor diffusion through a stagnant gas
:
~ layer comprising an elongated capillary conduit of predetermined
cross-section area and length having one closed end, and a
:j
~, vaporizable substance contained in said conduit, said stagnant
',Z! gas layer overlaying the vaporizable substance in the conduit.
''I .
In another particular aspect the pr.esent invention provid.es
a device for dissemination of a vaporizable substance at a
jl predetermined rate by vapor diffusion through two stagnant.. gas
:J 30 layers comprising an elongated capillary conduit of predetermined
~, cross-section area and length having one common sealed region
:;~
3 ~ .t~
:': : : : . .-. - :
, . . ' ' ' ' ' ' ' '
io~j4;~
between two open ends, said sealed region defining two portions
of said conduit, a vaporizable substance contained in each of
said portions of said conduit, and a stagnant gas layer overlying
said vaporizable substance in each said portion of said conduit.
In yet another particular aspect the present invention pro-
vides a device for dissemination of a vapori~able substance at a
predetermined rate by vapor diffusion through stagnant gas layers
comprising a plurality of elongated capillary conduits of pre-
determined cross-sectional area and length, each conduit having
one closed end, a vaporizable substance contained in said conduit,
and a stagnant gas layer overlying said vaporizable substance in
said conduit~
In a further particular aspect the present invention provides
; a device for the dissemination of a vaporizable substance at a
; predetermined rate by vapor diffusion through stagnant gas layers
comprising a plurality of elongated capiliary conduits of pre- -
~L determined cross-sectional area and length each conduit having two
open ends with a common sealed region therebetween and a vaporizable
substance contained in each conduit, said stagnant gas layers
. 20 overlying said vaporizable substance contained in each conduit.
Other ob;ects, features, and advantages of the invention will
be in part apparent and in part pointed out hereinafter.
:'
`, As evidence of the significantly improved controlled release
capabilities of our invention, some data have been collected from
the prior art and are presented, in Table I(A), below. Similar
experlments performed by the present inventors involving the use
of micro-tubes of polyethylene terephthalate open at both ends
disseminating one of the pheromones identified in Part (A) is
presented in Table I(B). By way of comparison, illustrations of
¦ the present invention are shown in Table I(C).
, : . . `'~' `
10~i4391
P. . ~ c~ ~I a~ Ul ~ W ~ 1-- _~ W ~ 1-- ~ W ~ 1~
~q ......... " ....... W
~c ~u~w 1~,
~ ~D O (D O 1'~ 1
W ~ t C ~ O O I
~3 r~ r~
N 1'-
O O O (7 ~ (D
C~ 0 ~0 ~` `
O p) ~ O IJ W C~ I
I_ I ~ r~
::C ~ . H
H t~ O ~
H Z ~ tW
., z ~ U~ ~ .'
H W W
Q ~ -h Z C1 ~ ~ ~ tri
~ ~SO (D ~ C ~
pJ V~ O O O O O C O O X C ~ O
W ~~ ~1 W
P~ I Q r~ r~ ri~ rl r~t-T~ r~ W O
t O I I ~ ~ pJ . p) p~ p~ U~ (D U~ ~d
~:: IJ O ~ pJ 1~ ~ ~1
0 0 0 1' ~ I' I'- IJ- (D Z ~
rD ~ ~3 ~3
(D (D fD O H
~ C:
,. ID ~ tD W
~ ~ N H ~3 :
., ~ U~ ~;
pJ p) W t~
o (D ~D , ~:
rl rl H . ..
. ~D (D H
., zo
.:
,, ......... ... . .. ~ ~ .
,P W ~ H 1~ :
co ~ ~3
~, ~ . ~ ~n ~
~'; ......... ... . .. _ ~3 ~
:~, OOooooool-- l_1--0
,, ~ ~ w ~ ~ ~ W ~ ~ ~ ~ ~ ~ tv ~ ,_ ~ '
Jl Ul ~ .
.~, _~ '
"', O 1~ ~ o ~1 I
.~ ......... ... ~q ~)
,~ oOOOoOoOO ~001~ o ~
-,'` O O O O O O 1--0 0 ~ 1~) o ~ 3
:, o o o o o ~ ~o o a~ o It C
'~ ~ O ~ O o ~ ~ ~
~ I_ I_ W
. ~'
W
0
" O 0 ~1 ~ 0 0
.~1 ,,,,,,,,, , .
..~ oooooo~oo 1- o 1~ ~i
,,; 1--o 1--o t~ ' ~
~( O ~ O O O ~ (~ ,~ ,p ~ H ~ .
i`, .~n ,P o~ ~ W :, ', '
:~, . ' ' .'.' -
"
,~ .
. .
,~.
. ,~, . . .~ ~ , .
10~ 91
It is seen from I(~) that the dissemination rate for
frontalin normalized to the hollow cross-section of the fiber
is 40 mg/mrn2/hr,in the work by Pitman and Vité using glass
capillaries 0.4 mm in diameter held verkically. This should
be compared with our work using the'same chemical in 0.4 mm
PET tube open at both ends held vertically [Table I (B)~ .
,
The differcnce between 40 mg/mm2/hr and 10 mg/mm2/hr can be
accounted for in that the method of Pitman alld Vité involves
the use of an olfactometer with a controlled forced velocity
of air across the open end of the tube, where,as in our experiment
the evaporation was carried out in a laboratory with virtually
stagnant air. The evaporation in both cases occurs at the air-
liquid interface continuously presented at the bottom of the
micro-tubes. In our experiment, the same micro-tube he'ld
horizontally results in a disseminalion rate of 7.1 mg/mm2/hr,
somewhat lower than when held vertically. A smaller (0.16 mm)
capillary when held vertically exhibits the slightly lower rate
of 6 mg/mm2/hr, but still quite comparable to that experienced
, . . .
~' with the larger capillary. The important point to be noted is
that all these tests lie in the same order,of magnitude of dis-
'' semination level, i.e., 10 m~/mm2/hr.
' By contrast now with the material in Table I, Parts
(A) and (B), there are data presented in Table I(C) on the
controlled prolonged rate of dissemination exhibited by the
methods of our invention. The first two lines in I(C) present
information on the dissemination of frontalin from two different
, sizes of micro-t~be. It will be seen that these two rates are
'~ quite consistent with one another, being .054 and .045 mg/mm2/hr.
-, These values differ by a factor of 200X from the data in I(B),
,4' d~
3~
and by as much as ].,OOOX from the data in I(~). Lines 3 and
4 of I(C) present evaporation rates for two very common
materials, carbon tetrachloride and ortho-dichlorobenzene,
one of high and the other of moderate volatility. It is seen
that their dissemination rates are in the proportion of 10:1
relative to one another, quite in keeping with their relative
vapor pressures at room temperature. However, by contrast
with the dissemination of heY~ane [Line 1 of Table I(A)~, with
a volatility comparable to carbon tetrachloride, they are in .
the order of 1,000 to 10,000 times less rapidly evaporated.
The remainder of Table I(C) describes dissemination rates for
a number of pheromones. Line 5, describing the dissemination
of looplure (c~ 7-dodecenyl acetate), should be contrasted
with the work of Shorey shown on the second line of I~A).
Here it will be seen ~hat there is a ten-fold reduction in
dissemi.nation rate by our invention. Line 6 data describing
c~-8-dodecenyl acetate is quite consistent with the dissemin-
`- ation data for the c~-7 isomer. The data of lines 7, 8, and
. 9 are further confirmation of the capabilities of our invention.
. 20 Table II provides the chemical descriptions and
insect targets for several of the selected pherornones for
which data is presented in Table I.
. .
,
.; ' .
~ - , ' .
~ dg/~ ' 12- ~
io~43s~
t' ~ c~ ~q g
~0 ~ X ~ n ~ g I ~ ~ ~ :~ ~
O O O O R. rt c~ P~ n o ~a o
O tD ~ O Z
~s o ~ ~ ~ ~a
(D 1-- 00 0 0 ~ 0 ~ O r~ ~ Z
D O r~ ~3
H H H ~1 :S n
H H ~ 1 J
H O I-- ~D ~--
P~ ~lt g
" ~ P' O
.. O H
Z O
~ ~ O
~` X ~ m ~o i~i
o
w w ~ ~ I 0 ~1 I pJ H 1~ Z
O ~ n
~ 1- w ~ ~ ~ ~ ~ ~ ~ Z
:: O E~ ~ (D w ~D w ~ O ~ n 1- tl ~ ~ .
(D ~ X I ~C I IJ O ~D ~ I ~ O ~ ~ :
~D ~t (D w ~ O ~ ~ ~ ~ ~
n~ 5 X ~ ~ tt w ~ ~ ~ o ~ Fu ~3
D 3 ~ O ~ O ~s ~ ~i H ~ ~;
~:: ItD ~ rt ~ (~ 1~ p) (D . I ~ ~ tr ,~ C ~ t~
1~ t~3 tq ~
- ~ P~Pl I N :5 ~ H H
n ~ p- D J I-- $ I (D (D ~ ~ 3:' H
r~ O o I ~ t (D L~ t
PJ n 1--D ` ` ~ ~ C
0 (D ~S O rt~
~D Pl ` I ' I 1- ~ tD X ~ ~3`
... ~ ~2 n t~ ~ ~
~ o . ~ i;3
n
0- i o
o ol o ._ Z ,.
., ~ ~
"H H
h ~,
,,., p, oW ~, ~S~< D ~, ~ .
~ 1- (D (D U) G~
",, p) ~ ~ 5'. W ~ ~ I I ~ :
O ~ 0 H
3 ~ U~
., O ~- W ~ t~J
:
a) ~3
.,~ O
.':
`:
",~,
`. .
~ .
10~i4;~91
`~ The invention accordingly comprises the elements
and combination of ele~ments, eatures of construction, and
- arrangements of parts which will be e~emplified in the structures
hereinafter described, and the scope of the application of
which will be indicated in the appended claim.
In the accompanying drawings, in which several of
the various possible embodiments of the invention are illustrated:
Fig. 1 is an elevation in section, showing a represen-
tative filamentary tube of this invention filled with a
vaporizing material.
Fig. 2 illustrates a group or stack of the Fig. 1
filled tubes mounted on a base in upright position.
Fig. 3a illustrates a method of assembling a con-
' tinuous parallel array of filled hollow fibèrs on an adhesive
backing tape, with periodic melt-sealed zones occluding the
`' tubes, and Fig. 3b illustrates how a single dispenser can be
cut from such a tape.
~;v' Fig. 4b illustrates a single hollow fiber filled with
.. ..
~; evaporant, open at one end and self-sealed shut at the other
by melt bonding; Fig. 4a illustrates the same configuration of
hollow fiber where the fiber has not been severed through the
heat-sealed region but consists o two microcondui~s each with
one open end and one ciosed end.
`~ Fig. 5 is a graph illustrating the release rate of
; carbon tetrachloride using this invention, being Example 3 of
Table I(C) given previously.
Fig. 6 is a graph illustrating the release rate of
~, o-dichlorobenzene using this invention, being Example 4 of
Table I(C) given previous]y.
., , ~ .
.. ,~ ,
~'; dg/~ 13-
.... .
;;~ .
10~4;~9~
Fig. 7 is a graph illustrating the release rate of
linalool using this invention, being Example 7 of Table I(C)
given previously.
' Fig. 8 is a graph illustrating the curve of release
rate for disparlure, using this invention, being Example 8 of
Table I~C) given previously.
- Fig. 9 is a graph illustrating the curve of release
rate for grandlure, using this invention, being Example 9 of
Table I(C) given previously.
Fig. 10 is a plot of release vs. time for frontalin
disseminated from a double-open end tube, being Example 3 in
Table I(B) presented previously.
Fig. 11 is a plot of release vs. time for frontalin
disseminated according to this invention, being Example 1 of
Table I(C) presented previously.
Fig. 12 is another embodiment of the invention in
which, instead of using separate tubes, flat sheets are embossed
to form channels (rectangular channels being shown, although
; they could be other shapes, such as semi-circular) and this
sheet is adhered to a base sheet in order to provide a plurality
of parallel capillary tubes. The channe]s in this illustration
are unfilled and unsealed.
Fig. 13 illustrates transverse sealing zones imposed
on the parallel array of channels in Fig. 12, after filling
' same with latent evaporant.
Fig. 14 is another view of the device of Figure 3,
in which a structure is shown having the tubes fastened to a
material such as an adhesive coated backing tape, and wilh the
' .
~ dg/~J , -14-
:~ .
10~;~391
tubes heat sealed to close them at regular intervals along the
length of the structure.
~ ig. 15 is an end view, enlarged, of the Fig. 14
structure.
Fig. 16 is a view taken of the Fig. 14 structure, in
the direction of sight lines 16-16, the view being in section.
Throughout the drawings, similar reference characters
indicate corresponding parts. Dimensions of certain of the
parts as shown in the drawings may have been modified and/or
exaggerated for the purpose of clarity of illustration and
understanding of the invention.
- This invention contemplates as a preferred embodiment
the use of hollow fibers as reservoirs and dispensers for the
vapors to be disseminated for several purposes (such as fragrances
for artificial flowers), but particularly for insect sex phero-
., o
mones where pheromones are emp~yed as trap baits or as a means
- of interrup~ing natural insect mating processes by the so-called
disruption technique. Pheromone deposited in the core of hollow
filaments of appropriate length and internal diameter is released
~0 by evaporation from one end of a small tube, the other end being
~ sealed.
; The hollow filaments of the invention may be made from
,~ . , .
any one of a number of natural or synthetic polymeric materials
by any of the processes commonly employed in producing man-made
fibers. Useful materials include polyesters, polyolefins,
acrylics, modacrylics, poiyamides,and so on. The selection of
an appropriate material will be governed by considerations of
chemical compatibility or inertness of the fiber material with
. .
.
,. .
.. . .
: . .
~ dg/~ -lS~
10~3~1
the chemical agent or formulation to be incorporated in and
released from the hollow filament. Where broadcast distrihution
of the pheromone hollow filaments is contemplated, such as when
employing the disruption technique, environmental considerations
might dictate the use of a biodegradable fiber material.
Regenerated protein or cellulosic fiber materials would satisfy
such a requirement.
Referrillg now to the drawings, as illustrated in Fig.
l, a capillary tubular filament 2 of this invention, which has
a bore or lumen 4, is closed at one end by means such as heat-
sealing or a plug 6 such as epoxy cement or other suitable
material, and is loaded with the insect attractant 8. The attrac-
tant 8 has preferably a wetting type meniscus lO at its open or
upper end in respect to the tube material. If such a meniscus
is not obtained as between the vaporizable material and tube,
then for a given vaporizable material the proper tube material
is selected.
Referring to Fig. 2, a group 12 of tubes 2 is shown,
these tubes being held together by conventional means (not shown),
such as an exterior wrapping or by being cemented together or
by being placed in a suitable outer container. The open ends of
the tubes are at the top and the bases oE the tubes are mounted
by conventional means on a support or base 14. The total amount
of insect attractant, or flower fragrance, where the invention
is used to provide a fragrance for artificial flowers, that will
be released, will depend, as set forth above and below, on the
size of the tubes, the particular material used, and the number
of tubes which make up the group 12. Since there is an extremely
- large number of possible variations of these factors, it is
dg//~ 16-
- :~ :~ , - . - . . . . - . .
: -. . . - : , - ~ : -:
~0~i4;~
impossible to list all of the combinations nor is it necessary
to understand and apply this invention. Persons skilled in the
art can readily bundle the required number of tubes once the
release rate of a given tube containing a given material is
known. As was illustrated in Table I(C), for exemplary insect
attractants, the release rate is readily determinable. There-
fore, all that is needed to design a disseminator for a given
total quantity of material is to take the number of hours of
release desired, the weight of the insect attractant needed for
that number of hours; the amount of attractant per tube will be
known by simple computation and then the number of such tubes
which need to be placed together to form a group 12 can be
readily computed (i.e., by dividing the attractant amount per
tube into the total amount).
Referring to Fig. 3a and Fig. 3b, another emboaiment
of the invention is shown, where a group of capillary tubes like
tubes 2 are adhered to a backing tape, periodically sealed along
their length, and which, as shown in Fig. 3a, can be rolled up
; in the form of a dispensing tape. The insect attractant 8 does
not escape from the tubes until the tubes are severed at selected
spots between seal regions. Further detail on this method is
given by Figs. 14, 15, and 16.
The above two embodiments illustrate two ways of
mounting the tubes, and the groupings of the tubes can be large
or small, depending upon the particular requirement. In actual
use, around a field of plant life which it is desired to protect
from insects, a number of the structures of either Fig. 2 or
. . .
" ' .
dg//~ 17-
10~3~
Fig. 3 can be placed, so that regardless of which way the wind
blows, insects will be attracted to at least some of the sites.
Generally, these embodiments(will be used in configuration with
insect traps for the monitoring of pest populations or tlleir
elimination by-direct trapping. Fiyure ~ illustrates another
embodiment wherein single filled fibers are sealed and cut to
expose one or two closed-end channels. These singl'e fibers may
be dispersed broadcast over crops or fields from suitable
ground-based or airborne dispensers and may be used for the
disruption method of pheromone application.
Referring to Fiy. 5, there is shown a typical release
rate curve (plotted in terms of weight loss as the ordinate
against time as the abscissa) of carbon tetrachloride which is
used as an exemplary material in order to establish a model
release rate~ It will be observed that at the very start, the
weight loss is relatively high, as indicated by that portion of
the curve A which falls steeply shortly after the start of the
release. The curve then flattens out and becomes almost hori-
zontal as indicated at the portion B. It is this prolonged low
level of release that comprises one of the Most important virtues
, or our invention. The exact shape of the curve varies somewhat,
depending upon the material used and the size of the tubes, but
in general it can he said that the curves of all materials tested
fall in a similar class of curves.
Referring to Figs~ 6, 7, 8, and 9, curves are shown
for the use of the invention, respectively, for ~-dichloro~
~enzene, linalool, disparlure, and grandlure, respectively.
Their compositions or chemical name are as follows:
,~ .
.
dg/~ 18-
. - ~ .: ... . ~ : .. : .
~0643~:1
linalool - terpcne alcohol
disparlure - c~-7, 8-epoxy-2--methyloctadecane
grandlure - a mixture consisting of:
(a) c~4-2-isopropenyl-1-methylcyclobutylethanol
(b) c~4-3, 3-dimethyl cyclohexylidenethal;ol
(c) c~-3, 3-dimethyl cyclohexylideneacetaldehyde
(d) ~an~-3, 3-dimethyl cyclohexylideneacetaldehyde
Where controlled release of more than a single sub-
stance is desired, it is possible to employ bundles or groups
of individual fibers charged with different volatile materials.
By appropriate selection of individual fiber diameters or the
relative numbers of fibers charged with different materials,
vapor mixtures can be disseminated with controlled composition.
. .
Examples of this variant are (1) the combined use of attractants
and toxicants, (2) attractants which are chemical mixtures or
which require a chemical synergist in precise ratios in order
~ to be effective, and (3) fragrances or deodorants requiring a
- mixture of chemicals for optimum effect.
`- This variant is particularly useful where mixtures of
chemicals of subst.antially different volatilities must be dis-
pensed to give a vapor mixture of rather constant composition.
,
Appropriate selection of fiber lengths, as well as diameter or
number, al-lows one to compensate for different rates of evapor-
ation, thereby delivering a vapor mixture of controlled and
constant composition. The variant is also useful when the mater-
ials one desires to release simultaneously at a controlled rate
are incompatible with one another (i.e., immiscible or chern-
ically reactive) in the condensed phase.
~ . .
,
, dg/ /;,~,r~ -19-
` 10~i43~3~
As indicated above, the purpose of having tubes o
different si~s is that the variation in the diameters of the
tubes is one of the factors that controls the rate of evapor-
ation or release rate of the attractant. Instead of using tubes
of various diameters, an alternative is to use tubes of the
same size but use more tubes filled with one materiai than the
number of tubes filled ~ith another material, the ratio of tubes
determining the resu]tant vapor compound ratio. If, for example,
in a vapor dispersion of two compounds, it is desired to have
three parts of one compound to one part of the other compound
as the vapors mlx on emerging from the tube ends, then a bundle
of tubes of a predetermined like diameter would have three times
as many tubes of one compound as there are tubes of the other
compound, thus giying the required compound mixture. Of course,
in obtaining a vapor which is a mixture, the evaporation rates
of the individual vaporizable materials need to be considered
as factors, and evaporation rates can be usefully employed to-
gether with tube diameters, or rat]os of tubes of one material
to tubes of other materials, to obtain the desired vapor. The
combinations of such variables are almost infinite in number and
therefore are not set forth herein. , It is possible by this
technique and by this invention to produce vapors comprising a
plurality of discrete compounds. In actual practice, what the
manu~acturer of the device could do would be to preload tubes
of various materials; and then on a custom order basis, the
requisite number of tubes would be bundled in accordance with
the customer's desires as to the relative proportions of the
emergent vapor. In compounding the tube bundles, o~ course,
','~
~g//~ 20-
, . .
., , , - : - - : . ~
10~;439~
the weight loss curves for the scveral compounds would be taken
into consideration.
As an example, if the customer desires an attractant
to~ether with an insecticide the vapor of which is the ~illing
factor, the customer wou]d order tubes some of which irl the
bundle would contain the attractant and the other would contain
the insecticide liquid., The vapors mix as they emerge from the
tubes to produce a mixture of the desired amount of insecticide
and attractant. The attractant would attract the insects to
the site where the bundled tubes would be stationed, and upon
the insects going to the area of the vapors, the insecticide ~-
.
would kill them.
Fig. 10 is a plot of release rate v~. time for front-
alin dissemination according to prior art methods from a 0.4 mm
PET micro-tube, being the data of Line 3 of Table I(B). It
illustrates the high constant rate characterizing this method.
Fig. 11 illustrates dissemination of the same pher-
omone from the same tube as used in Eig. 10, except as defined
by the present invention. It clearly shows the significantly
lower controlled rate achieved after the initial rapid fall in
.;'' .
rate as described for the previous examples of this invention.
(Note that the abscissa ln Fig. 11 is in gms/hr X 105 while
that in Fig. 10 is in gms/minute X 105.)
Referring now to Fig. 12, an embodiment is shown in
.
which the capillary tubing is provided by first forming a sheet
indicated generally by numeral 40 in such a manner that it has
~;
~,~
` the channels 42 therein. These channels are shown as five in
."
~`~ number, but any number desired could be utilized. Also,
1, .
~, . . .
~ .
dg/b~J -21-
~ . .
: . S~ , ' .. ' . ~ . `.. . , ', ' : .
~0~;4391
channels ~2 arc shown as being rectangular in cross-secti.onal
configuration, but semi-circular, oYal, or other polygonal
channels could also be used. It will be noted that the bottoms
of the channels are open, and the sheet 40 is then adhered to
a base sheet 4~ by attaching the webs 46 securely to the base
sheet ~4 using conventional adhesives. As a resul-t, between
the base shèet 44 aild the channel members 42 are provided the
capillary tubings 48 as shown, of predetermined cross-sectional
shape and size.
Fig. 13 illustrates the composite sheet channel system
of Fig. 12 filled and sealed across the conduits, as at 4g.
Referrin~ now to Figs. 14, 15, and 16, more detail is
shown of the embodiment of the invention illustrated by Figures
3a and 3b. An elongated strip 64 of suitable material having
an adhesive coating 66 thereon is utilized. Such a material
can be conventional masklng or wrapping tape which is coated
with a pressure-sensitive adhesive. A plurality of filamentary
tubes 68 is stretched lengthwise along the combined tape 64, 66,
these filamentary tubings being held to the tape by means of
~ 20 the adhesive 66. If it is desired, the adhesive 66 can be of
;` the ]cind which prior to use is coated with a protective pull-
off cover, but in use when the cover is removed and the tubes
68 are adhered thereto, tlle adhesive then sets in air in order
to form à strong fastening of the tubes 68 to the strip 64.
The tubes 68 may be placed upon the strip 64 before
or after being filled. ~fter they have been filled and are
mounted upon the strip, they are heat sealed along the junction
lines 70, the tubing material being o a kind which can be heat
.
dg/~ -22-
., ~ ,,~,o64391
scaled b~ the applicatioll of a heated sealing member. By so
heat sealing, the tuhing wall is collapscd at the points 70
thus providing for each elongated tubing a plurality of sectlons
72, each section 72 being but a portion of a total length of
the individual filaments. In use, the user will cut c;cross the
tubings`in order to provide sllort conduit elements of the desired
length of tubing, the cutting taking place between the heat
- sealed portions 70. The length of tubing sections from the
closed heat sealed end to the o~en end, where the cutting tak.es
place, will determine, other parameters being considered in
; accordance with the teaching of this invention, upon the actual
length of the individual section 72. The Figs. 14-16 embodiment
give a convenient way in which to supply to a prospective user
either a roll or a flat length of filamentary tubes, already
mounted on a base, but in which the tubes are sealed against
any loss of material until it is desired to use the tubes. When
the user desires to use a certain portion, he will take the
material and from an end he will then cut the length of tubing (the
' cutting ta~ing place across the width of the strip) in order to
20 open the ends of the tubing. The length of the tubing which he
determine$ to cut will depend (other factors can also be con-
sidered) on the number of hours he wishes the cut length of
tubings to emit their vapors.
In the practice of this invention, the tubular fibers
of polymeric material fabricated to convenient dimensions are
, loaded with an insect attractant by one of the methods described
.; .
below. The hollow ~iber dimensions for practical consideration
i:
~, are generally in the range of approximately 0.025 to 1.0 milli--
`'~! meters in external diameter, and 0.01 to 0.8 millimeters in
:~ ,..
, ~ , .
` dg/~ -23-
.~ . , , . , ,, . ~ .
. ,. . -: : , , , . . :
. .
~o~39~
internal diameter, althou~h it will be obvious to one familiar
with the art of ~iber extrusion that micro-tubes both larger
and smaller th~n these limits are attainable and may be considered
variants of this invention. (In the ensuing description, the
conventional abbreviations of the metric system will be used,
for example, mm for millimeters, cm for centimeters, and g for
grams.) The illustrated dimensions represent, therefore, a
preferred rather than a limitin~ range. Elollow fiber length
will be governed by the length of time desired for release of
the attracting agent. Thus, for a given attractan~ material,
the invention allows control over release rate through the
nu~er and lumen dial~eter of fibers employed and control over
the period of activity through selection of appropriate fiber
length. Release rate curves describing the character of release
behaviour for this invention typically show a brief period of
; high release rate followed by a long period of somewnat asympto-
tic behavior, where the release rate decline, as reflected in
the slope of the "asymptotic" portion of the curve, is so small
as to approximate a linear release rate. Such release rate
curves are given below in respect to several of the examples of
the invention that have been made and tested successfully.
The ~ollowing examples will serve to illustrate the
practice and utility of this invention.
; EXAMPLES
Example 1.
.
This example was ~iven as Line 3, Table I(C) and
describes the release or evaporation behavior of carbon tetra-
: chloride ~a model compound for relatively volatile attractants
;
d~ 24-
10f~43~
or insecticidcs), from undrawn hollow flbers of polyethylene
terephthalate. Fiber dimensions were 0.254 mm external diameter
and 0.203 nun internal diameter. Hollow fiber lengths of 127;0
mm to 203.2 ~n were loaded with carbon tetrachloride, sealed
at one end with an epoxy potting compound, and mounted in a
vertical position, open end up, on a flat surface. The lumen
cross-sectional area was approximately 3.245 X lO 4 cm . Loss
of carbon tetrachloride from the ~iber core by evaporation and
diffusion out of the open end of the fiber was measured by
following the liquid meniscus recession into the fiber interior
by means of a cathetometer. Incremental volume losses converted
to weight losses and plotted as a function of time are displayed
in Fig. 5. In this case, a quasilinear release rate is observed
after 30 hours.
The release was measured at quasi-steady rate of weight
loss, and the figure given is the average of five samples each.
Example II
.
0-dichlorobenzene, serving as a model for insect
attractants or insecticides of intermediate volatility, was
loaded by a capillary filling technique into an undrawn poly-
ethylene terephthalate hollow fiber with lumen cross-sectional
-4 2
areas of 3.09 X lO cm . Filled hollow fibers 127 mm in
length were sealed at one end with an epoxy potting compound,
and mounted in a vertical position, open end up, on'a flat sur-
face. Release of the 0-dichlorobenzene from the hollow fibers
was observed and measured by following meniscus recession into
the fiber interior~ Fig. 6 displays the release curve for this
experiment, the data having previously been given as Line 4
- dg/~ 25-
-
'.,. . . -. . ., . , , , , , - - ':- . . ' , ''. . : . .
, ~ . . . . . , . , . - - . .: . : - , .
~- - - . .. . .
~0~1~3~1
of Table I~C). The quasillnear release rate was reached at
about 90 hours.
Example III.
The data for this Example was Line 7 of Table I(C).
The terpene alcohol, linalool, chosen as a model for grandlure,
the aggregating pheromone of the cotton boll weevil, was loaded
into undrawn polyethylene terephthalate hollow fibers with a
lumen cross-sectional area of 3.14 X 10 4 cm2. 102 mm to 127 mm
lengths of loaded fiber, sealed at one end with a potting com-
pound, were mounted in a vertical position, open end up, on a
flat surface. Release of the linalool from the hollow fibers
was monitored by following meniscus recession into the fiber
witll a cathetometer. Fig. 7 is the release curve for linalool.
After about 40 hours, the release rate becomes steady at 5 X 10 9
g/min. Assuming a desired release rate for a boll weevil bait
of 3 X 10 4 g/day, and a required attraction period of 168 days,
a bait configuration is calculated to require 42 fiber open
ends with individual fiber lengths of 3.8 cm.
Example IV
This data was given on Line 8 of Table I~C). ~ispar-
lure, the sex attractant for male gypsy moths, was Ioaded into
undrawn polyethylene terephthalate hollow fiber with a lumen
cross-sectional area of 3.4 X 10 4 cm2. The disparlure release
curve was obtained as described in Example I. The release rate
became steady at 1.44 X 10 6 g/day/fiber end as seen from the
release cuxve displayed in Fig. 8. The desired release rate
~or a gypsy moth sex pheromone trap bait is 2.16 X ln 4 g/day
and the desired period of activity is 90 days. Thus, a hollow
~:
.
. . .
dg//~ 26-
~6439:1.
fiber trap bait would require three fiber open ends and an
indivldual fiber length of 0.46 cm per open end.
A commercial insect trap lined with a sticky substance
to hold attracted moths in the trap was baited with disparlure
loaded hollow fibers and placed in a wooded area of Nc;rfolk
County, Massachusetts, during the month of August, 1974. The
pheromone baited trap captured male gypsy moths at a ratio of
3:1 over an unbaited trap.
Example V
;~ 10 This data was given as Line 9 of Table I(C). Grand~
lure, the aggregating pheromone attractant of the cotton boll
weevil, was loaded into undrawn polyethylene terephthalate
hollow fiber with a lumen cross-sectional area of 3.14 X 10 4
cm . The grandlure release curve was obtained as described in
Example II. Release rate became steady at 5 X 10 9 g/min/fiber
end, as shown in the release curve displayed in Fig. 9. The
: desired release rate for a cotton boll weevil pheromone bait is
3 X 10 4 g/day and the desired period of activity is 168 days.
Thus, a hollow fiber trap bait would require 40 fiber open ends
with individual fiber lengths of 24 cm per open end. -
The manner in which attractant materials are charged
:~ into the hollow filaments of this invent]on may be one of several.
`; The liquid attractant formulation will fill the hollow filament
by capillary action or by gravity feed using the filament as a
siphon. ~In the siphon method, one end of a tube or tubes is
` inserted in the desired liquid. The other ends of the tubes are
` below the liquid surface. A slight suction is applied to the
;; lower ends. Once the liquid flow has started, then the siphon
.
.
.^`' ' '
dg/~ -27-
~0~;~391
action continues and the tubes fill.) Another filling method
involves simply sucking liquid into the fiber core by placing
fiber ends heneath the liquid surface and evacuating the fibers
from the other end by means of a suction bulb or aspirator
device. Yet another involves placing fiber segments ~;eneath
the liquid surface and compressing them to force out air, after
which they contract and dxaw the fluid. It is also possible
to fill the fiber at the time of spinning by injecting the
liquid attractant formulation as a core fluid during the spinning
operation. Other methods of filling the filament capillary may
come to mind, but it should be noted that the particular method
of filling is not a part of this invention.
In view of the above it will be seen that the several
objects of the invention are achieved and other advantageous
results attained.
It is understood that the invention is not limited in
its application to the details of construction and arrangement
~ of parts illustrated in the accompanying drawings, since the
.~ invention is capable of other embodiments and of being practiced
or carried out in various ways. Also, it is to be understood
that the ~hraseology or terminology employed herein is for the
purpose of description and not of limitation.
. . . .
As many changes could be made in the above constructions
` without departing from the scope of the invention, it is intended
; that all matter contained in the above description or shown in
the accompanying drawings, shall be interpreted as illustrative
and not in a limiting sense, and it is also intended that the
appended claims shall cover all such equivalent variations as
come within the true spirit and scope of the invention.
. .
dg/ ~ -28-
` ' ,' ' : " '
