ZA200506510B - Two-stage dispensing mat - Google Patents

Description

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R TWO-STAGE DISPENSING MAT

C_ROSS-REFERENCE TO RELATE D APPLICATIONS . [0001] Mot applicable.

STATEMENT REGARDING FEDER ALLY SPONSORED

RESEARCH/DEVELOPMENT

[0002] “Not applicable.

BACKGROUND OF THE IINVENTION

[0003] The present invention relates to disp ensing volatile mater—als such as insecticides, in sect repellants, fragrances, and deodeorizers. It provides nats designed to release the v-olatile material when the mat is heat ed.

[0004] 1t is known to impregnate or coat a solid porous mat with_ a volatile material, and/omwr to place a volatile material in a me#al pan-like structure. These structures are t hen placed on heaters to cause the volatile to vaporize inteo the ambient air. See generally U.S. patent 6,031,967 and WO 9/66791. The disclo=sure of these publications, a-nd of all other publications referred &o herein, are incorpo rated by reference as if fully set forth herein.

[0005] However, there can be a time lag between the initiation owfthe heating of the mat and when the concentration of active in “the room reaches a dessired level.

For cxample, wvhen the mat contains an insecticide, it may take a few mEnutcs before the desired lev=el of protection from mosquitoes or other insects is achie~ved. Thisis a particular prololem where the product is primarily clesigned to provide a prolonged release of acti~ve (e.g. to provide overnight protecti on against mosquitoe=s).

[0006] To minimize the time lag, one could try increasing the cconcentration of active in the nmat. However, actives are often costlsy, and in any event th_e increased concentration may lead to unnecessarily high level s of insecticide or otlmer active being dispenseed into the air after the initial period. : [0007] Another approach would be to modify heaters so that the=y work at one temperature d_uring an initial phase and then work at a reduced tempera—ture at all other ) times. Howewer, much of the public is unlikely to want to throw away their existing heaters and paay the cost of new ones having this capability. In any event, including this capability. in future heaters would unnecessari ly increase the cost o fsuch heaters.

= “WO 2004/073399 PCT/US2003/004451

[0008] U.S. patent 5,657,574 proposed a mosquito ceoil having a uniform concentration of insect control agent spread throughout it, buat with the coil having ama enlarged ignition end. When the coil was first lit an extra biarst of insecticide was dispensed because more of the coil was burnt at that time. H=owever, this approach is not suitable for a mat where the entire bottom of the mat is designed to be exposed to the heat source at once.

[0009] WO 99/6679 1 provided a slab-type mat for imsertion in an indexed fashion into a heater. Discrete regions of the mat are heated in sequence. The primarsy purpose of the slab is to provide a mechanism for indexing a new mat section over the heater when the preceding sesction had been used up. Howeveer, the publication also describes that the sequential xegions could carry different volatile ingredients or different concentrations of thme same volatile ingredient. that is given is providing a high concentration section to be used at night anc a low concentration section to be used during the day. Unfortunately, this approamch requires the user to sequentially move the slab when the next stage of usage is desired.

[0010] In WO 02/17977 our company recently disclo sed a mat comprising an outer mat and a central lower section separated by a vertical groove extending through the mat. Different insecticides, or different concentrations of= actives, could be provided in each of the two cellulosic sections. The central s ection was typically heated more quickly (as low «ost heaters, such as those typically used in developing countries, often heat the hottest near the center of the heater). As a result, the insecticide in the central portion was dispersed more quickly, while that in the outer mat was dispersed more slowly.

[0011] These mats were somewhat difficult to manufacture because the material had to be cut entirely through, resulting in multiple oieces needing to be assembled. This added to thes cost of production. . [0012] - U.S. patent 4,439,415 described a substrate for= dispensing insecticidal vapors having distinct regions impregnated with different insecticides or other ' volatiles. The distinct regions were provided either on a single substrate with the sections separated by a substance for rendering the material neon-absorptive, or were constructed from different pieces of substrate which were coupled together. The device again required multipl< parts.

[0013] GB 2,122,903 taught a substrate having an aluminunm foil bottom layer on which ©ne or more paper segments were mounted. The segments were divided by separators, which were constructed of rulbbber or synthetic resins whi ch prevented permeatiom of liquid. Therefore, differemmt volatiles could be provide=d on the segments without having a volatile from a first segmment move to a second segrment. This method also required difficult manufacturing steps.

[0014] Accordingly, a need still exists for improved volatile -dispensing mats.

SUMMARY OF THE INVENTION

[oo15] The present invention prowides mats for dispensing volatile vapors. In one form tThere is a substrate having a firs-t substrate portion and a second substrate portion, thee second substrate portion bein_g positioned at least sornew~hat radially outward of the first portion.

[0016] There is also an upwardly open depression formed in zan upper wall of the substrate, and a moat formed in an upper wall of the substrate radlially outward from the upowardly open depression. The first substrate portion is radllially positioned between th. €¢ upwardly open depression armd moat, with the upwardly open depression preferably “being essentially centrally loca ted cup structure.

[0017] The first substrate portion Jhas applied thereto a first volatile material, the volatile material comprising an active selected from the group cornsisting of insect control agents, fragrances, deodorizers, armd combinations thereof. Tle second substrate portion is positioned radially outward of the moat and has applied thereto a second volatile material which is an actives selected from the group consisting of insect control agents, fragrances, deodorizzers, and combinations thereof. [ooisl The first volatile material c=an have an active that is not present in the second volatile material, or the second vol_atile material can have an a_ctive that is not present in the first volatile material. Alternatively, one can provide thae first volatile . material with at least one active that is the same as an active in the second volatile material, buat that active is present at differ—ent concentrations in the first volatile : material thawn in the second volatile materiaals (typically higher in the first volatile material).

[0019] As yet another alternative, the first volatile material cam have at least one active that is the same as an active in t_he second volatile material,. but the

Ig WO 2004/073399 PCT/US2003/00445 1 remainder of the first volatile material may not be entirely iclentical to the remainder of the second volatile matesrial. In this regard, one can retarc or increase the rate of™ release by the selection of suitable solvents or binders.

[0020] The term “mat” is used herein to include any structure suitable for u=se with conventional vapor di spensers, regardless of the precise shape. Slab-like mats. are preferred.

[0021] The term “irsect control” is defined to mean Killing, repelling, or otherwise altering the behavior or development of insects. “Insect control agent” is used herein in its broadest sense to include not only insecticides and repellants but also growth regulators and other agents capable of achievings insect control. “Insect=" is defined to mean actual irasects as well as spiders, millipedes, and other small animals commonly controlRed in the same manner or with th same agents as are insects. :

[0022] The locatiom of the upwardly open depressiorw in the substrate can be selected to be generally cermtered over the heater's hot spot when positioned over the= heater. Thus, for most mats the upwardly open depression will be at the radial center of the mat.

[0023] In an insect «control application, we prefer to tase a more highly volati”le active for the central depression. Particularly preferred is where the active in the volatile material of the outesr substrate region is Pynamin Forte whose release rate is somewhat slowed with pipesronyl butoxide and the active in the volatile material of the central depression is tramsfluthrin.

[0024] Another forrm the invention provides a method for controlling insects .

One places such a mat on a heater, and then heats the mat to thereby cause the first and second volatile materials to be dispensed from the mat.

[0025] In yet another form of the invention there is provided a method of . constructing such a dispensing mat. One obtains a slab of a substrate material. One then simultaneously compresses a central portion of the slab and also a portion that : radially surrounds that central portion, to thereby form an upwvardly open central depression radially surrouncled by a moat.

[0026] One then deposits a first volatile material in th e upwardly open centraml depression, and deposits a second volatile material that is different from the first volatile material on a portion of thae slab radially outward of the moat. The moat: acts to mirimize bleed between the tweo portions of the mat (e_ g. while the mat is beirg stored. for shipment, inventory, or store display). [002 7] This method can al so include the further st=ep of adhering a metall ic layer con a bottom surface of the sl ab. This causes heat frcom a heater to be more quickly spread out (e.g. heat from a heaters hot spot is spmread under the full subsstrate that h=as been impregnated). [002 8] When used as an immsect control device, the device of the inventiorm allowss the user to achieve desired protection very quickly, without sacrificing lorg-

LO term protection. When dispensing= a deodorizer or fragrarmce, the invention has time advantage of covering over existirmg malodors very quickl—y (e.g. in a bathroom), without sacrificing the ability to pmrovide fragrance over thee long term.

[0029] The present inventi on is further capable of turning a disadvantage of inexpensive heaters (non-uniform heating across the heati—ng face) into an advantage.

This iss achieved by placing the certral depression over a central portion of the he=ater. [003€0] These advantages a-re achieved while perm-itting a very efficient manufacturing process to be able t-o produce the item. A 1 ow cost stamping operation can quuickly form the upwardly open depression and moat, and the impregnation can be facilitated through the use of thee cup.

[0031] It should be appreck ated that the cup has tw—o primary functions. F irst, it prov—ides a quick way of impregrating the central region . of the mat (one can pour the volatile into the cup and let it s eep through the side wa_lls of the cup into the fairst portiorn). This reduces the period Of time necessary to cause an effective impregznation, thus speeding up thes manufacturing processs.

[0032] Second, the bottom of the cup is closer to time heater. In some embod_iments (e.g. when material nas been removed), this reduces the insulation effect — of the mmaterial itself, speeding up the initial burst of active= once heating begins.

[0033] These and still othem advantages of the pres- ent invention will appear - from tke following description. In that description reference is made to the accompanying drawings in which there is shown by way o- {illustration preferred embod._iments of the invention. Ho wever, the claims shoul .d be looked to in order to judge the full scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[C0034] FIG. 1 is a perspective view of a dispensing mat of the present imvention which has been positiosned on a heater;

[0035] FIG. 2 is a sectioraal view of the dispensing mat of FIG. 1, taken along litne 2-2 of FIG. 1;

[0036] FIG. 3 is a top plan view of a substrate portion_ of the mat with a ceentral depression formed thereir; [ 0037] FIG. 4 is a top plan view of the FIG. 3 substrate, but with a moat also formed therein; [ 0038] FIG. 5 is an exploded perspective view of the FIG. 1 mat; and [ 0039] FIGS. 6A-6F are top views of alternate embodmments of mats of the present invention.

DETAILED DESCRIPTT ON OF THE PREFERRED "EMBODIMENT [#0040] Referring first to F=I1G. 1, a mat 10 is shown pla-ced upon a horizontal buramer face 12 of an electric heater 14. The heater 14 can be aan electrical-resistance heater, such as the heater sold by as the RAID® heater by S.C. Johnson & Son, Inc.

Heowever, other heaters could also be used, including without Rimitation those with horizontal, vertical, or other orien tation of their heating surfacees. [C041] The mat 10 is primarily a slab-like substrate 16 in which a cup-shaped de=pression is provided at the appreoximate center and a circumferential moat 20 is preovided a short distance from thes central depression 18. The —moat divides the sulbstrate 16 into a first/inner substrate portion 22 (provided between the central depression 18 and the moat), and a second substrate portion 24 (located radially outside of the moat 20). [O®042] Referring now to FIG. 2, the substrate 16 can be constructed either by rernoving material from the center of the substrate 16 or by cormpressing that material, . Sirmilarly, the moat 20 can be cut out of the substrate 16 or starmped using a corrnpression device. Most prefera bly, the depression 18 and mmoat 20 are : simultaneously formed in a single compression stamping appliexd at the top of the subostrate. [0 043] The depression 18 zand moat 20 preferably do nowt extend through the bot=tom of the substrate 16, such th.at the substrate 16 remains a single piece of

= WO 200-8/073399 PCT/US2003/004451 material. The first and second sub strate portions 22 and 24 may be treated with diffesrent active(s), and/or different: levels of actives, or be provided with different non—active additives to create vary sing rates of dispersion or waried effectiveness.

[0044] In the most preferre-d mats of the present inve=ntion the substrate 16 is adhe=red to a metal foil backing 26. This improves heat cond _uction from the heater 14 alon_g the mat 10. [00-45] The upper part of th_e substrate 16 is preferabl—y a pulp/cellulose-based matezrial such as a cardboard, or a cardboard cotton mix. The substrate can be sized and «iimensioned to be placed on thme heating surface 12 of a conventional heater 14. [00 46] Alternatively, the substrate could be formed of other porous materials such as synthetic fibers, sintered glass, polymeric blocks, pla=stic beads, natural or synthetic fabrics, ceramic materials (such as terra cotta or ear—thenware), and other absoxrbent and adsorbent porous materials. When ceramic maaterials are used, the centr—al depression 18 can be coated with a suitable ceramic g_laze, such as silica-based low £ire clear glaze. [00-47] FIGS. 3 — 5 show mat 10 in various stages of construction. After an appropriate material for substrate 16 is selected, the central depression 18 is formed in the suabstrate 16. The circumferential moat 20 is also formed. [00&8] In the most preferred. form the inner substrate oortion 22 is in the shape of a 1-fesaver. FIGS. 6A-F show that the central depression 1=8 and the moat 20 can be provi-ded in a number of different stmapes, which result in the portion 22 having a variet=y of other shapes. It is most dessirable that the moat completely, or at least to the extent of 180°, surround the central «depression 18 to help sep=arate the first substrate portion 22 from the outer substrate oortion 24. This moat help s minimize bleeding of active= or volatile from the inner subsstrate portion 22 to the out=er substrate portion 24.

[0049] As the moat will typiscally not be cut all the wa=y through the slab, there . could be some slight bleeding betwe en the portions 22 and 24, near the metal foil backirmg 26. However, where the moat is relatively deep, bleeding is essentially : prevemted, especially during the heatzing step when the volatile=s are most mobile. [005 0] Referring now to FIG-. 5, a metal foil backing l=ayer 26 can be adhered to the bottom side of the substrate 1G. The layer 26 can be maede of an aluminum or other metal foil, and it can be adhere«d to the substrate, such as by using a polymeric adhesive. O-ne such adhesive is “711” (comrmercially available from Manufacturer :

Resources, Inc. of New Berlin, Wisconsin). Other acceptable adhesives: are made of acrylic, uretlnane, or other temperature resistant materials. Other methods of joining a metallized foil to the substrate 16 can alternatively be used.

[0051] After the substrate 16 is joine«d to the metallized foil backing layer 26, a first volatile material 28 containing a desired active can be dripped or gpoured into the central deepression 18. The material 28 quickly bleeds into the first portion 22, thereby impregnating it. The moat 20 inhibits still further bleeding or creeping of active to the rest of the mat 10 to the outer sumbstrate portion 24.

[0052] A second volatile material 30 containing an active, whiclm preferably is different frorm that in the first volatile material, can be coated, impregnated, or otherwise applied to the outer substrate portion 24. The moat 20 also limits bleeding of the second volatile inwardly towards the fi rst portion 22.

[0053] The outer substrate portion 24 can be impregnated with a second volatile material 30 having a slower releasings active ingredient and the c entral depression 18 can be coated with a chemically distinct first volatile mate-rial 28 having a fastesr releasing active ingredient. As the most preferred insect «control device, the sescond volatile material 30 is 100 mg of a liquid solution hav-ing a chemical conciposition of 40% Pynamin Forte™ (an insecticide active ingredient), 40% piperonyl but-oxide (PBO, synergist/release agent), and 20% Isopar M (hydrocarbon solvent).

[0054] A first volatile material 28 for use with such a mat is 50 mag of a liquid solution havimg a chemical composition of 4% transfluthrin (insecticide active ingredient) arad 96% Isopar E (hydrocarbon solvent). Transfluthrin vaporizes more quickly than does the Pynamin Forte because it has a higher vaporization_ pressure.

[00551] Alternatively, the volatile mate=rials 28 and 30 could inclucie any other . suitable know=n insecticides, repellants, growth regulators, or other insect control agent. For ex_ample, the volatile materials 22 znd 24 could include organic ; phosphorus irasecticides, lipidaniide insecticid es, natural repellants such aus citronella oil, natural py-rethrum and pyrethrum extract, sand synthetic pyrethroids. Suitable synthetic pyresthroids include allethrin as D-alRethrin, Pynamin®, benfluth-rin, bifenthrin, S-tioallethrin, esbiothrin, esbiol, ba oresmethrin, cycloprothrin_, cyfluthrin,

beta-cyfluthrin, cyhalothrin, deltamethrin, empenthr—in, esfenvalerate, fenprop athrin, fenvalerate, flucythrimate, tau-fluvalinate, kadethrin, permethriri, phenothrin, prallethrin as Etoc®, wesmethrin, tefluthrin, tetrametlmrin or tralomethrin. Othe=r volatile insecticides as described in U.S. patent 4,439,415 can also be used.

[0056] Volatile insect growth control agents such as methoprene and hydroprone may also be used. Alternatively, or in addition, fragrances and deodorizers may be used, such as limonene, eucalypt=us, and citronella.

[0057] Although moat 20 has been shown to effectively limit creep or bleeding of the active 28 from the first substrate portmion 22 to the second substrate portion 24 (and vice v-ersa), the moat 20 can also be t.reated with a sealant such as a rubber, a resin, or ano ther type of material preventing absorption of the active 28 to help prevent any creep of actives.

[0058] In one form, when the mat 10 is first hs eated, the mat 10 provides for a very high volume burst of dispensed volatile material 28. Thereafter, the rate of dispensing levels off as the remaining dispensing larg=ely occurs from the secord portion 24. This helps quickly protect or otherwise mmodify the environmental conditions of an area raot previously subject to adequaate treatment, while provicling long-term protection thereafter.

[0059] In one orm (which is somewhat similamr to the FIG. 4 version, but with a wider moat), the central depression 18 can be center ed in the substrate 16, ancl can have a diameter of about .34 cm. The moat 20 canbe in the form of a ring having an inner diameter of about 1.06 cm and an outer diameter— of about 1.75 cm. The Jepth of this substrate 16 care be about .26 cm, and the deptha. of each of the central depression 18 and moat 20 can be about .1 cm or deep er.

[0060] A number of variations in the construction of the central portion 18 and moat 20 are shown in FIGS. 6A-F. In particular the m_oat 20 is shown as a poly gonal . configuration (6A), elliptical configuration (6B), as a sstar (6C), as a wide circle (6D), as a contoured star (6E), and as a four arrow pattern (6_F). The color of each of &he : different mat regions can be separately and differently dyed, such as by includimg varied dyes in the impregnation materials. Where the clye is also volatile, the chmange or fading of color can b e a use-up cue. The shape of thme central portion 18 can zulso be varied, ssuch as is shown in FIG. 6B, wherein an elliptical center depmression 18 is - shown. [00617 Although a single moat 20 is shown, it will be appare=nt that a mat with multiples concentric moats, in a “bull's-eye=” pattern, and other varyinmg volatiles could also be Provided so as to create three or me ore different dispensing re=gions. Still other variatiors to the preferred embodiments are intended to be within thes scope of the claims a.s well.

[0062] Moreover, the mat of the pr-esent invention could also- be a disinfect-ant/fragrancer/deodorizer, using any of a wide variety of act ive ingredients for such purposes, including without limitations glycols, trimethylen-e and dipropylene known ira the art. Further, even with the seame active and substrates, =a mat constructed in accorclance with the present invention could work if solvents, binders, and the like were adjmusted to suitably control release ra tes. For example, the middle volatile could contain Pynamin Forte in a hydrocarbon solvent, while the outer volamtile could be the same, alloeit with some piperonyl butoxide- Accordingly, the claims :=should be reference=d in order to determine the full sceope of the invention.

INDUSTRIAL APPLICABILITY

[0063] The invention provides impmoved mats for the controll _ed release of insect comtrol agents, fragrances, disinfectants, and similar useful, voBatile materials, particular-ly those where a more vigorous dispensing occurs when the product is first used.

Claims (15)

1. A mat for dispensing volatile vapors, comprising: a substrate having a first substrate portion aned a second substrate portion, the second substrate goortion being positioned at least somewhat radially outward of the first portion; an upwardly open depression formed in an upoper wall of the substrate; a moat formed in an upper wall of the substrate radially outward from the upwardly open depression, with said first substrate p- ortion being radially positioned between the upwardly open depression and moat; said first substrate portion having applied the=reto a first volatile material, the volatile material comprising an active selected from the group consisting of insect control agents, fragrances, deodorizers, and combina tions thereof: and the second substrate portion being positioned. radially outward of the moat. and having applied thereto a second volatile material, the= second volatile material comprising an active selected from the group consist ing of insect control agents, fragrances, deodorrizers, and combinations thereof.

2. The mat of claim 1, wherein the first wolatile material has an actives that is not present in the second volatile material.

3. Th.e mat of claim 1, wherein the secorad volatile material has an active that is not present in the first volatile material.

4, Th.e mat of claim 1, wherein the first wolatile material has at least one active that is the same as an active in the second volamtile material but that active is present at a differ ent concentration in the first volatil e material than in the second volatile material.

5. Th.e mat of claim 1, wherein the first wolatile material has at least o ne active that is the same as an active in the second volatile material but the remainder of

. the first volatile nnaterial is not completely identical t=o the remainder of the second volatile material.

6. Th e mat of claim 1, wherein the upwardly open depression is radially centrally positioned in the substrate.

7. Th.e mat of claim 1, wherein the moat completely radially surround s the upwardly oper depression.

8. The mat of claim 1, wh erein the substrate is ma_de at least in part of a cellulosic= material and is mounted on & lower metallic layer.

9. The mat of claim 8, wh erein the upwardly open_ depression and the moat wer-€ formed by compressing portions of the substrate.

10. The mat of claim 1, wherein an active in the se—ond volatile material is Pynamin . Forte and an active in the firsst volatile material is trarsfluthrin.

11... The mat of claim 1, wherein a portion of the mat is in the shape of an arrow. : 12. The mat of claim 1, wherein the moat is in the s hape of a star.

° WO 2004/073399 PCT/US2003/00445 1

13. A method for controlling insects, comprising: ) obtaining a mat having: a subsstrate having a first substrate porticon and a second substrate portion, the second substrate portion being positioned aut least somewhat radially outward of the first pwortion; an upwardly open depression formed in an upper wall of the substrate; a moat formed in an upper wall of the substrate radially outward fro-m the upwardly open depression, with said first substrate portion being radially positioned between the upwardly open depression and mmoat; said fi rst substrate portion having applie=d thereto a first volatile material, the volatile material comprising an active selescted from the group consisting of insect control agerats, fragrances, deodorizers, and combinations thereof; and the second substrate portion being positioned radially outward of the moat and having applied thereto a second volatile material, the second volatile 1= material comprising aan active selected from the group consisting of insect control agents, fragrances, desodorizers, and combinations there=of; placing the m at adjacent a heater; and heating the m at to thereby cause the first and second volatile materials to be= dispensed from the mmat.

i WO 2004/073399 PCT /US2003/004451

14. A method of constructing a dispensing mat, the method comprising: oo obtairming a slab of a substrate material; simul#@aneously compressing a first portion of the slab and alse a portion radially surrounding the first portion to thereby form an upwardly ope=n central depression raedially surrounded by a moat; depositing a first volatile material in the upwardly open centra_1 depression; and depos-iting a second volatile material that is different from the first volatile material on a portion of the slab radially outward of the moat.

15. The method of claim 14, further comprising the step of= adhering a metallic layer— on a bottom surface of the slab.