CA2044049A1 - Articles containing microencapsulated materials - Google Patents
Articles containing microencapsulated materialsInfo
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- CA2044049A1 CA2044049A1 CA 2044049 CA2044049A CA2044049A1 CA 2044049 A1 CA2044049 A1 CA 2044049A1 CA 2044049 CA2044049 CA 2044049 CA 2044049 A CA2044049 A CA 2044049A CA 2044049 A1 CA2044049 A1 CA 2044049A1
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Abstract
ARTICLES CONTAINING MICROENCAPSULATED MATERIALS A novel article comprising a coherent array of a multiplicity of stacked elements having at least one surface thereof formed by edges of each of the stacked elements. The article is coated on at least one of the so formed surfaces with a bonded layer of rupturable microcapsules containing a releasable core material, e.g., a fragrance.
Description
AR~IC~ES CONTAINING MICROENCAPSULATED MATERIALS
_ ~ie1d of the Invention __ __ . _ Thi~ inventlon relates to ar~icle~ contalning microencap~ulated material~. ~n par~icular, this invention relates to articl~s containi~g mlcrocapsules which relea~e thair flll upon rupture of the mlcrocap~ule6.
~ack~round o~ the Invention Encapsulated mater~als have been u~ed for many years in a wide variety of commercial appllcation~.
Early use~ oP encap~ula~ed materials included paper coated wlth capsule~ bear~ng color-~orming mat~rial thereln whlch could be used as a recording medium. U.S.
Patent Wo. 3,016,30~ disclo~es one o~ tha early ~forts using ~ncap~ulated material as khe image source on record~ng paper. u.S~ Patent No~. 4,05~,434 and 4,201,404 disclose other me~hods o~ appllcatlon of encapsulated color-forming materials on paper substrates to be u~ed as imaging media and the like. U.S. Patent No- 3,503,7~3 di6close~ microcap~ul~ having color-~orming material thereln which are rup~urablq by the applica~ion o~ heat, pressure and/or radlation becau~e oP a metal coating on thq sur~ac~ oP thQ
capsule. The~e rupturable microcap~ules, ln one 2mbodlment, may be secured between a sub6trate and a photoconductive top coat to enable photvsen~itive imaging o~ the system.
A wide variety of process~s exist by wh~ ch - microcap~ules can be manufactured. The~e varied processe~ prov~de differ~nt techniques for producing eap~ules of varying sizes, alternative materials for th~
compo~ltion of the capsule shell, and variou~ d~erent fu~ctlonal materials wi thin the shell. Some of these variou~ proces~es are ~hown ln U.S. ~a~ent No~.
3,516,846; 3,516,941; and Brltish Patent Specl~ication No6. 1,156,725; 2,041,319; and 2,04B,206. ~ wide variety of different materials may also be used in making the capsule shells. ~ popular material for shell formation i8 the product of the polymerization reaction between urea and formaldehyde or melamine and formaldehyde, or the polycondensation products of monomeric or low molecular weight polymers of dlmethylolurea or methylolated urea with aldehydes. ~ variety o capsule forming materials are disclosed, for example, in U.S.
Patent Nos. 3,516,846 and 4,087,376 and U.K. Patent Specification Nos. 2,006,709 and 2,062,570.
As shown in these reerences, the principal utility of microencapsulated materlals i6 in the formation of a surface coated with the microcapsule6 in a blnder. The microcapsules are ruptured by various means to release the material contained therein. In addition to release of physically observable material
_ ~ie1d of the Invention __ __ . _ Thi~ inventlon relates to ar~icle~ contalning microencap~ulated material~. ~n par~icular, this invention relates to articl~s containi~g mlcrocapsules which relea~e thair flll upon rupture of the mlcrocap~ule6.
~ack~round o~ the Invention Encapsulated mater~als have been u~ed for many years in a wide variety of commercial appllcation~.
Early use~ oP encap~ula~ed materials included paper coated wlth capsule~ bear~ng color-~orming mat~rial thereln whlch could be used as a recording medium. U.S.
Patent Wo. 3,016,30~ disclo~es one o~ tha early ~forts using ~ncap~ulated material as khe image source on record~ng paper. u.S~ Patent No~. 4,05~,434 and 4,201,404 disclose other me~hods o~ appllcatlon of encapsulated color-forming materials on paper substrates to be u~ed as imaging media and the like. U.S. Patent No- 3,503,7~3 di6close~ microcap~ul~ having color-~orming material thereln which are rup~urablq by the applica~ion o~ heat, pressure and/or radlation becau~e oP a metal coating on thq sur~ac~ oP thQ
capsule. The~e rupturable microcap~ules, ln one 2mbodlment, may be secured between a sub6trate and a photoconductive top coat to enable photvsen~itive imaging o~ the system.
A wide variety of process~s exist by wh~ ch - microcap~ules can be manufactured. The~e varied processe~ prov~de differ~nt techniques for producing eap~ules of varying sizes, alternative materials for th~
compo~ltion of the capsule shell, and variou~ d~erent fu~ctlonal materials wi thin the shell. Some of these variou~ proces~es are ~hown ln U.S. ~a~ent No~.
3,516,846; 3,516,941; and Brltish Patent Specl~ication No6. 1,156,725; 2,041,319; and 2,04B,206. ~ wide variety of different materials may also be used in making the capsule shells. ~ popular material for shell formation i8 the product of the polymerization reaction between urea and formaldehyde or melamine and formaldehyde, or the polycondensation products of monomeric or low molecular weight polymers of dlmethylolurea or methylolated urea with aldehydes. ~ variety o capsule forming materials are disclosed, for example, in U.S.
Patent Nos. 3,516,846 and 4,087,376 and U.K. Patent Specification Nos. 2,006,709 and 2,062,570.
As shown in these reerences, the principal utility of microencapsulated materlals i6 in the formation of a surface coated with the microcapsule6 in a blnder. The microcapsules are ruptured by various means to release the material contained therein. In addition to release of physically observable material
2~ such as ink in order to form a visible image, other types of active ingredients such as odor relea~$ng materials, bacteriostatic materials, chemically active materials and the like have been provided in this manner.
U.S. Patent No- 4,4B7,801 descrlbe6 the U6~ 0~
a non-pres~ure ~ensitive adhesive layer between two sur~aces, the layer having ~ragrance containing micro-capsule~ therein. Upon separation o~ the two surfaces, the adhe~ive and the microcapsules are ruptured, releasing the fragrance. U.S. Patent No. 4,720,417 shows a 6imilar article in which at least one of the two sur~ace~ is a coated paper surface.
U.5. Patent No. 4,661,38B discloses micro-encapsulated materials which are released by the removal of individual elements from a pad of sheets bonded by adhesive layers containing the microencapsulated materials.
U.S. Patent No- 4,4B7,801 descrlbe6 the U6~ 0~
a non-pres~ure ~ensitive adhesive layer between two sur~aces, the layer having ~ragrance containing micro-capsule~ therein. Upon separation o~ the two surfaces, the adhe~ive and the microcapsules are ruptured, releasing the fragrance. U.S. Patent No. 4,720,417 shows a 6imilar article in which at least one of the two sur~ace~ is a coated paper surface.
U.5. Patent No. 4,661,38B discloses micro-encapsulated materials which are released by the removal of individual elements from a pad of sheets bonded by adhesive layers containing the microencapsulated materials.
-3~
The principal utili~y of the microencapsulated materials disclosed in the foregoing three re~erences is to release a scent or ~ragrance. Whereas tha~e fragrance releasing articles have had a high degree of commercial ~ucce6s, thers has exlsted a vold in the market place ~or stationery items which can release a scent as well.
In the past, it has been considered tedious and difficult to apply rupturable microcapsules to stationery items, such as a pad of writlng paper or a packet of sheets. Since it was thought that the surf~ce of such items on which one would write would be the most logical place to apply the rupturable ~lcrocapsules, each 8he~t of paper would have ~o be coated lndlvidually to apply a layer of rupturable mlcrocapsule6 which i5 a lS labor ~ntensive and time consuming process.
Additionally, the microcapsules would have to be applied at the ti~e of manufacture of the writing pad or other artlcle slnre it would be very difficult to coat each individual sheet of the article once they are c~mpressed together in the Pinal product. Consequently, there would be no opportunlty for changing the type of fill or matarial to be relea~ed upon rupture of the microcapsule~ applied to th~ pad or packet o~ sheets once the article went into production.
It was agalnst this background that Applicants began their search for novel articles containlng rupturable microcapsules which would not have the disadvantages discussed abov0.
~rie~y o~ the Invention The present invention relates to a new article containing rupturable microcapsules. The novel article comprises multiple elements (usually in the form of sheets) in a stacked, coherent array, the accumulation of at least one edge of each of the mult~p.le el~ments forming ât least one surface of the article. ~he surface~s~ of the article formed by the accumulation of edge~ of the individual stacked elements ar~ a~ lea~t _4_ 2 ~ f~
partlally coated with a layer compri~ing rupturable microcap6ule6 containing relea~ahle core materlal thereln. At lea~t 60me oE the mlcrocap6ules are ruptured by removing one or more ~heet~ or other elements from the article. The removal of the individual sheets causes some of the microcapsule~ in the layer coated on the edge of the sheet removed to rupture and release the flll contained therein.
The novel article of the present lnvention containlng rupturable microcapsules does not fiuffer ~rom the di~advantages o~ oth~r mlcrocap~ule cont~lning articles discussed earlier herein. To b2gin with, slnce the articles of this invention are coated with microcapsules on the sur~ace(s) of the article formed by edges of the individual stacked sheets or other elements in the article, rather than on each surface of the indlvidual sheet6 themselves, the task of coating the article with microcapsules is much easier than in conven~ional processes. Addltionally, the microcap6ule6 can be applied to the article after the stacked array of element6 or sheet6 is produced and consequently, the speci~ic type of fill material to be used in the rupturable mlcrocapsules can be changed a~ter productlon of the ~tacked array of multiple elements has been co~pleted In thi~ appllcatlon:
"coherent array" mean6 a mul~lplicit~ o~
individual elements, e.g., sheets of paper, which are adhered to each other;
'tensile strength" or l'tensile rupture strength" means the breaking strength of a sub~tance, which may be a composite article, when subjected to a tensile (stretching) force;
"cohesive tensile strength" or "cohesive strength" means the tensile strength of a speci~ied materlal; and "flexible" mean~ carl be bent at a rounded angle of 120 without racturing.
5- 29~A13~.9 Detalled Descriptlon of the Inventlon The present lnventlon relates to a novel article comprising multiple elements ~e.g., sheets) in a coherent, stacked array, the accumulation of at lea6t one edge of each of the multiple elements formlng at lea6t one susface of the article. At least a portion o~
one or more of such surface6 formed by the edge~ o~ the individual elements contains a layer comprising rupturable mlcrocapsules containing a releasable fill or core material therein.
The stacked array of multiple elements contained in the artiole o~ the present invention is typically a pad or packet containing a multipliclty (e.g~, 50, 100, or more) sheets of paper, fllm forming materlal, or other flexible materlal with p~per being presently preferred bPcause of its 1exibility. The multlple elements contained in the article of thi~
invention will be stacked in a coherent array so that the individual elements are preerably substantially parallel to one another within the article. Other po6sible configurations for the article o~ the present lnvention inciude, but are not llml~ed to, ~ g~ntle splral or a zig-zag formation.
The individual elements, e.g., sheets of paper, etc., present withln the article wlll be bonded toge~her by a suitable adhesivo. I~ the artlcle is in thc ~orm o~ a cube, e.g., Post-itTM Note cubes ~available rom 3M), or an ordinary pad of writing papar, then the adhesive, e.g., latex or rubber based, is applied to one of the swrfaces formed by the edges of the individual elements or sheets. Microcapsules will not be present in that surface of the article. If the article ~s in the form of a Post-it~M Note pad (available from 3M) or ~he like, then the individual sheets or elements are bonded together through the u~e of a pressure sensitive, e.g., acrylic, adhesive present on the underside o~ each sheet or element. Such -6~ 2 ~ 9 adhe~lve layer will not, oP coursH, contain mlcrocap~ules eith~r. In the present invention, the abov~-d~crlbed arrangements ACe the two prlmary mode6 for bonding the individual ~haets or elem~nt~ of the article together.
As disclosed hereln earlier, at lea~t one surface o~ the article formed by the edge of the multlplicity of individual elements contains a layer of rupturable microcapsules containing a releasable core or fill material, preferably a fragrant llquid such a~ an oil. Preferably, two of the so formed ~urfaces will he coated with the layer of microcapsules. If the article contain~ a surface formed by the edges of the element~
whlch i~ coated with a suitable adhesive (e.g., latex or rubber) to bond the sheets or elements together, then ~hi~ surface doe~ not contain microcapsules as stated earlier herein.
The microcapsules are bonded together in the layer to be applied to the surface(~) of the artlcle by a suitable polymeric or natural binder. Suitable polymeric and natural binders include, but are not llmited to, polyacrylates, polyvlnyl r~6in~ ~e.g., polyvinyl alcohol, polyvinyl chloride, and polyvlnyl acetatc), epoxy reslns, polyamide~, polyc~ter~, polyolefin~, starches, gum arabic, and the llke~ The~e polymeric and natural binders serve a~ a ~econdary mode ~or binding the individual sheets together, the primary mode~ having be0n de~cribed earller herein.
~ he microcapsules used in the prflsent invention may comprise any rupturable shell wall material, such as, for exa~ple, urea~formaldehyde, urea-melamine and gelatin. The microcapsule fill or core may also be any active ingredient such as a flavor, pigment, solvent, or fragrance, with the latter pre~erred.
Particularly preferred are organic oil~ which are fragrance releasing materials which readily volatize upon rupturing o the capsule. Whatever fill is u~ed in _7~ 2 ~
the microcap6ule~ can be u~ed ln the ~orm o~ a ~olid or a liquid.
Generally, the mlcrocapsules utillzed in the present invention will have an average diameter between about 4-100 microns, and pre~erably b~tween about 6~0 microns. The microcapsule will typically contain between about 50-9~ volume percent and pr2ferably 60-95 volume percent o~ fill based upon the total volume of the microcapsule.
A layer of microcapsule~ can be applied to at least one surface of the article (formed by the edges oP
the multiplicity of elements of the article~ by any conventional manner, e.g., by silk screening, kniPe edge coatlng, or application of an aerosol spray, utilizing a polym~r~C binder.
The binder used in the coat~ng layer must form a bond to the surface o4 the article whlch ls stronger than th~ cohe6ive ten6ile strength of the binder w~th the capsule~ dispersed therein. Also, the tenslle rupture strength of the microcap~ule~ should be less than the cohesive strength of the blnder u~ed. The coating of particles may be in a continuous or dlscontinuous layer.
The coatlng weight of binder and microcapsules 6hould be at a coatlng welght of approximAtely one pound for 300 to 1000 square feet of the ~ucface formed by the edges. Pre~erably, the co~ting weight should be between approximately one pound for each 400 to B00 square ~eet.
The capsules should form between 5 to 9B percent by volume of the total adhesive layer, and preferably between about 30 to 65 percent of the total adhesive layer.
The blnder layer (with microcapsul~) may be 3pplied in either a continuous or discontinuou~ fa~hion over at lea~t one sur4ace of the article.
In the practice o~ the present invention, removal o~ one or more elements (e.g., sheets of paper) from the article will cause some of the m~crocapsules in the layer to ruptur~, ~hereb~ relea~lng the ~ill material ~e.y., fragrance~ contained inside the microcapsule, The odor of readily vaporizable substance~
i~ lm~adlately noticeable.
The ~ollowing non-limiting examples further ~llustrate the present invention.
An oil havlng the aroma of MacInto6h appl~6 ~oil no. 3709-B from French Color & Chemical Company) were encapsulated in a urea-formaldehyde r~sin made according to the process of Example 20 of U.S. Pat. No.
3,516,941~ The capsules had an averaye diameter of about 9 micrometers and an estimated payload of 65% by weight ~ratio o~ oil to total capsule weight).
A slurry formulation containing the mlcroencap6ulated oil~ was used to coat three sides o~
3M Post-ltTM Note cubes ~2~3/4" x 2-~/4" x 2-3/4") at approximately one pound per 30Q to 1000 square feet uslng a piece of automatic verticle silk screen equipment using a 255 line screen.
Samples were produced and screened on the thr~e paper ~ides and not on the glue side o~ the cube~.
Dw~ll time was approximately 10 mlnute~, then th~ cubes were tunn~l drled at 50C for approxlma~ely 15 ~cond~.
A visible matte finish resulted with t~e sh~et edge6 lightly stuck together.
On removal of the 6heet rom the cub0, a crackling sound was heard as the capsules ruptured and a pleasant burst of the MacIntosh apple aroma was ~vldent.
Exam~le 2 A number of other Post-it~M Note cubes were similarly coated (as in Example 1) on two opposite edge ~tdes~ not on the glue side, with a dwell time of 10-12 minute6 and then tunnel dried for 15 seconds at 40~.
Thes~ prQduced a good crackling sound as the capsules _9_ ~ f. ~ ~ ~3 ruptured on individual ~heet removal with a very good feagrance eelease.
Example 3 Plain paper cubes with th~ lndivldual sheets held together with a rubber adhesive on one 6ide were ~imilarly coated (as ln ~xample 1) on the three other sides and tunnel drled for approximately 25 ~econds on 50C. Sh~et removal resulted in capsule breakage and the eelease o~ a pleasant waft of the aroma o~ MacIntosh apple.
~5
The principal utili~y of the microencapsulated materials disclosed in the foregoing three re~erences is to release a scent or ~ragrance. Whereas tha~e fragrance releasing articles have had a high degree of commercial ~ucce6s, thers has exlsted a vold in the market place ~or stationery items which can release a scent as well.
In the past, it has been considered tedious and difficult to apply rupturable microcapsules to stationery items, such as a pad of writlng paper or a packet of sheets. Since it was thought that the surf~ce of such items on which one would write would be the most logical place to apply the rupturable ~lcrocapsules, each 8he~t of paper would have ~o be coated lndlvidually to apply a layer of rupturable mlcrocapsule6 which i5 a lS labor ~ntensive and time consuming process.
Additionally, the microcapsules would have to be applied at the ti~e of manufacture of the writing pad or other artlcle slnre it would be very difficult to coat each individual sheet of the article once they are c~mpressed together in the Pinal product. Consequently, there would be no opportunlty for changing the type of fill or matarial to be relea~ed upon rupture of the microcapsule~ applied to th~ pad or packet o~ sheets once the article went into production.
It was agalnst this background that Applicants began their search for novel articles containlng rupturable microcapsules which would not have the disadvantages discussed abov0.
~rie~y o~ the Invention The present invention relates to a new article containing rupturable microcapsules. The novel article comprises multiple elements (usually in the form of sheets) in a stacked, coherent array, the accumulation of at least one edge of each of the mult~p.le el~ments forming ât least one surface of the article. ~he surface~s~ of the article formed by the accumulation of edge~ of the individual stacked elements ar~ a~ lea~t _4_ 2 ~ f~
partlally coated with a layer compri~ing rupturable microcap6ule6 containing relea~ahle core materlal thereln. At lea~t 60me oE the mlcrocap6ules are ruptured by removing one or more ~heet~ or other elements from the article. The removal of the individual sheets causes some of the microcapsule~ in the layer coated on the edge of the sheet removed to rupture and release the flll contained therein.
The novel article of the present lnvention containlng rupturable microcapsules does not fiuffer ~rom the di~advantages o~ oth~r mlcrocap~ule cont~lning articles discussed earlier herein. To b2gin with, slnce the articles of this invention are coated with microcapsules on the sur~ace(s) of the article formed by edges of the individual stacked sheets or other elements in the article, rather than on each surface of the indlvidual sheet6 themselves, the task of coating the article with microcapsules is much easier than in conven~ional processes. Addltionally, the microcap6ule6 can be applied to the article after the stacked array of element6 or sheet6 is produced and consequently, the speci~ic type of fill material to be used in the rupturable mlcrocapsules can be changed a~ter productlon of the ~tacked array of multiple elements has been co~pleted In thi~ appllcatlon:
"coherent array" mean6 a mul~lplicit~ o~
individual elements, e.g., sheets of paper, which are adhered to each other;
'tensile strength" or l'tensile rupture strength" means the breaking strength of a sub~tance, which may be a composite article, when subjected to a tensile (stretching) force;
"cohesive tensile strength" or "cohesive strength" means the tensile strength of a speci~ied materlal; and "flexible" mean~ carl be bent at a rounded angle of 120 without racturing.
5- 29~A13~.9 Detalled Descriptlon of the Inventlon The present lnventlon relates to a novel article comprising multiple elements ~e.g., sheets) in a coherent, stacked array, the accumulation of at lea6t one edge of each of the multiple elements formlng at lea6t one susface of the article. At least a portion o~
one or more of such surface6 formed by the edge~ o~ the individual elements contains a layer comprising rupturable mlcrocapsules containing a releasable fill or core material therein.
The stacked array of multiple elements contained in the artiole o~ the present invention is typically a pad or packet containing a multipliclty (e.g~, 50, 100, or more) sheets of paper, fllm forming materlal, or other flexible materlal with p~per being presently preferred bPcause of its 1exibility. The multlple elements contained in the article of thi~
invention will be stacked in a coherent array so that the individual elements are preerably substantially parallel to one another within the article. Other po6sible configurations for the article o~ the present lnvention inciude, but are not llml~ed to, ~ g~ntle splral or a zig-zag formation.
The individual elements, e.g., sheets of paper, etc., present withln the article wlll be bonded toge~her by a suitable adhesivo. I~ the artlcle is in thc ~orm o~ a cube, e.g., Post-itTM Note cubes ~available rom 3M), or an ordinary pad of writing papar, then the adhesive, e.g., latex or rubber based, is applied to one of the swrfaces formed by the edges of the individual elements or sheets. Microcapsules will not be present in that surface of the article. If the article ~s in the form of a Post-it~M Note pad (available from 3M) or ~he like, then the individual sheets or elements are bonded together through the u~e of a pressure sensitive, e.g., acrylic, adhesive present on the underside o~ each sheet or element. Such -6~ 2 ~ 9 adhe~lve layer will not, oP coursH, contain mlcrocap~ules eith~r. In the present invention, the abov~-d~crlbed arrangements ACe the two prlmary mode6 for bonding the individual ~haets or elem~nt~ of the article together.
As disclosed hereln earlier, at lea~t one surface o~ the article formed by the edge of the multlplicity of individual elements contains a layer of rupturable microcapsules containing a releasable core or fill material, preferably a fragrant llquid such a~ an oil. Preferably, two of the so formed ~urfaces will he coated with the layer of microcapsules. If the article contain~ a surface formed by the edges of the element~
whlch i~ coated with a suitable adhesive (e.g., latex or rubber) to bond the sheets or elements together, then ~hi~ surface doe~ not contain microcapsules as stated earlier herein.
The microcapsules are bonded together in the layer to be applied to the surface(~) of the artlcle by a suitable polymeric or natural binder. Suitable polymeric and natural binders include, but are not llmited to, polyacrylates, polyvlnyl r~6in~ ~e.g., polyvinyl alcohol, polyvinyl chloride, and polyvlnyl acetatc), epoxy reslns, polyamide~, polyc~ter~, polyolefin~, starches, gum arabic, and the llke~ The~e polymeric and natural binders serve a~ a ~econdary mode ~or binding the individual sheets together, the primary mode~ having be0n de~cribed earller herein.
~ he microcapsules used in the prflsent invention may comprise any rupturable shell wall material, such as, for exa~ple, urea~formaldehyde, urea-melamine and gelatin. The microcapsule fill or core may also be any active ingredient such as a flavor, pigment, solvent, or fragrance, with the latter pre~erred.
Particularly preferred are organic oil~ which are fragrance releasing materials which readily volatize upon rupturing o the capsule. Whatever fill is u~ed in _7~ 2 ~
the microcap6ule~ can be u~ed ln the ~orm o~ a ~olid or a liquid.
Generally, the mlcrocapsules utillzed in the present invention will have an average diameter between about 4-100 microns, and pre~erably b~tween about 6~0 microns. The microcapsule will typically contain between about 50-9~ volume percent and pr2ferably 60-95 volume percent o~ fill based upon the total volume of the microcapsule.
A layer of microcapsule~ can be applied to at least one surface of the article (formed by the edges oP
the multiplicity of elements of the article~ by any conventional manner, e.g., by silk screening, kniPe edge coatlng, or application of an aerosol spray, utilizing a polym~r~C binder.
The binder used in the coat~ng layer must form a bond to the surface o4 the article whlch ls stronger than th~ cohe6ive ten6ile strength of the binder w~th the capsule~ dispersed therein. Also, the tenslle rupture strength of the microcap~ule~ should be less than the cohesive strength of the blnder u~ed. The coating of particles may be in a continuous or dlscontinuous layer.
The coatlng weight of binder and microcapsules 6hould be at a coatlng welght of approximAtely one pound for 300 to 1000 square feet of the ~ucface formed by the edges. Pre~erably, the co~ting weight should be between approximately one pound for each 400 to B00 square ~eet.
The capsules should form between 5 to 9B percent by volume of the total adhesive layer, and preferably between about 30 to 65 percent of the total adhesive layer.
The blnder layer (with microcapsul~) may be 3pplied in either a continuous or discontinuou~ fa~hion over at lea~t one sur4ace of the article.
In the practice o~ the present invention, removal o~ one or more elements (e.g., sheets of paper) from the article will cause some of the m~crocapsules in the layer to ruptur~, ~hereb~ relea~lng the ~ill material ~e.y., fragrance~ contained inside the microcapsule, The odor of readily vaporizable substance~
i~ lm~adlately noticeable.
The ~ollowing non-limiting examples further ~llustrate the present invention.
An oil havlng the aroma of MacInto6h appl~6 ~oil no. 3709-B from French Color & Chemical Company) were encapsulated in a urea-formaldehyde r~sin made according to the process of Example 20 of U.S. Pat. No.
3,516,941~ The capsules had an averaye diameter of about 9 micrometers and an estimated payload of 65% by weight ~ratio o~ oil to total capsule weight).
A slurry formulation containing the mlcroencap6ulated oil~ was used to coat three sides o~
3M Post-ltTM Note cubes ~2~3/4" x 2-~/4" x 2-3/4") at approximately one pound per 30Q to 1000 square feet uslng a piece of automatic verticle silk screen equipment using a 255 line screen.
Samples were produced and screened on the thr~e paper ~ides and not on the glue side o~ the cube~.
Dw~ll time was approximately 10 mlnute~, then th~ cubes were tunn~l drled at 50C for approxlma~ely 15 ~cond~.
A visible matte finish resulted with t~e sh~et edge6 lightly stuck together.
On removal of the 6heet rom the cub0, a crackling sound was heard as the capsules ruptured and a pleasant burst of the MacIntosh apple aroma was ~vldent.
Exam~le 2 A number of other Post-it~M Note cubes were similarly coated (as in Example 1) on two opposite edge ~tdes~ not on the glue side, with a dwell time of 10-12 minute6 and then tunnel dried for 15 seconds at 40~.
Thes~ prQduced a good crackling sound as the capsules _9_ ~ f. ~ ~ ~3 ruptured on individual ~heet removal with a very good feagrance eelease.
Example 3 Plain paper cubes with th~ lndivldual sheets held together with a rubber adhesive on one 6ide were ~imilarly coated (as ln ~xample 1) on the three other sides and tunnel drled for approximately 25 ~econds on 50C. Sh~et removal resulted in capsule breakage and the eelease o~ a pleasant waft of the aroma o~ MacIntosh apple.
~5
Claims (14)
1. An article comprising a coherent array of a multiplicity of stacked elements, said article having at least one surface formed by an edge of each of said stacked elements, said article having a coating on said at least one surface with a layer of rupturable microcapsules containing releasable core material therein.
2. An article according to Claim 1 wherein said microcapsules in said layer are rupturable by removal of one or more of said elements from said article.
3. An article according to Claim 1 wherein said releasable core material is an odor releasing liquid substance.
4. An article according to Claim 1 wherein said microcapsules have an average diameter between about 4-100 microns.
5. An article according to Claim 4 wherein said microcapsules have an average diameter between about 6-80 microns.
6. An article according to Claim 1 wherein said microcapsules contain from between about 50-98 volume percent core material.
7. An article according to Claim 6 wherein said microcapsules contain from between about 60-98 volume percent core material.
8. An article according to Claim 1 wherein said microcapsules form between about 5-98 percent by volume of said bonded layer.
9. An article according to Claim 8 wherein said microcapsules form between about 30-65 percent by volume of said bonded layer.
10. An article according to Claim 1 in which said layer of microcapsules comprises binder and said microcapsules.
11. An article according to Claim 10 wherein said binder is one chosen from the group of polyacrylates, polyvinyls, epoxies, polyamides, polyesters, polyolefins, starches, and gum arabic.
12. An article according to Claim 10 wherein said layer of microcapsules is a continuous layer.
13. An article according to Claim 1 wherein one of said surfaces is coated with a latex binder which bonds together said stacked elements within the article.
14. An article according to Claim 1 wherein each of said stacked elements is undercoated with a pressure sensitive adhesive which bonds together said stacked elements within the article.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US56279390A | 1990-08-06 | 1990-08-06 | |
| US07/562,793 | 1990-08-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2044049A1 true CA2044049A1 (en) | 1992-02-07 |
Family
ID=24247808
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2044049 Abandoned CA2044049A1 (en) | 1990-08-06 | 1991-06-06 | Articles containing microencapsulated materials |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2044049A1 (en) |
-
1991
- 1991-06-06 CA CA 2044049 patent/CA2044049A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |