CA2191752A1 - Tacky microspheres prepared from vinyl ester monomers - Google Patents
Tacky microspheres prepared from vinyl ester monomersInfo
- Publication number
- CA2191752A1 CA2191752A1 CA002191752A CA2191752A CA2191752A1 CA 2191752 A1 CA2191752 A1 CA 2191752A1 CA 002191752 A CA002191752 A CA 002191752A CA 2191752 A CA2191752 A CA 2191752A CA 2191752 A1 CA2191752 A1 CA 2191752A1
- Authority
- CA
- Canada
- Prior art keywords
- monomer
- vinyl
- weight
- percent
- nonpolar
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F18/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid
- C08F18/02—Esters of monocarboxylic acids
- C08F18/04—Vinyl esters
- C08F18/10—Vinyl esters of monocarboxylic acids containing three or more carbon atoms
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F18/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid
- C08F18/02—Esters of monocarboxylic acids
- C08F18/12—Esters of monocarboxylic acids with unsaturated alcohols containing three or more carbon atoms
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J131/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid, or of a haloformic acid; Adhesives based on derivatives of such polymers
- C09J131/02—Homopolymers or copolymers of esters of monocarboxylic acids
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
- C09J133/04—Homopolymers or copolymers of esters
- C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
- C09J133/08—Homopolymers or copolymers of acrylic acid esters
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/14—Polymer mixtures characterised by other features containing polymeric additives characterised by shape
- C08L2205/18—Spheres
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/14—Polymer mixtures characterised by other features containing polymeric additives characterised by shape
- C08L2205/18—Spheres
- C08L2205/20—Hollow spheres
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J2301/00—Additional features of adhesives in the form of films or foils
- C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
- C09J2301/302—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Adhesives Or Adhesive Processes (AREA)
- Manufacturing Of Micro-Capsules (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
The invention provides tacky, polymeric, organic solvent-insoluble, elastomeric, pressure-sensitive adhesive microspheres prepared from vinyl ester monomers, to processes for their preparation, and to their use as pressure-sensitive adhesives.
Description
~o 96101281 ~ I 9 1 7 ~2 TACKY MICROSPHERES PREPARFn FROM VINYL ESTER MONOMERS
Field of thc Invention This invention relates to tacky, polymeric, organic solvent-insoluble, , pressure-sensitive adhesive l/~lUD,~Jh~ , prepared from vinyl ester monomers, to processes for their p~ a~liu~, and to their use as pressure-sensitive 10 adhesives.
Background of the Invention Tacky, ~laaLul~ uli~.~valJh~ are known to be useful in ~I r ~ - ~ I pressure-sensitive adhesive a, r As used herein, the term 15 ~I~r - ~ I N refers to the ability to be repeatedly adhered to and removed from a subdrate without substantial loss of zdhesion capability. i ' ua~ based adhesives are thought to perform well in such arr~ ' at least in part due to their "b.,L''~:' ' ,,1' character, wherein substrate, tend to be pushed aside and trapped between the ,. i-,. UD~ as the adhesive is applied. Upon removal, the 20 adhesive can then still present a relatively ., ~ Prl surfiace for ~ ;. " to the substrate.
Numerous references concern the l/lel.l.~ldLiOI'I and/or use of inherently tscky, ela.DtUlll~ acrylate polymeric ,..;.,.u .~ which are solid in nature The Liol. and uses of such Ill;~,l ualJh~ , along with their p ,~
25 prûperties~ are disclosed in U.S. Pat. Nos. 3~691~140 (Silver~; 4~166~152 (Baker et al.);
4,495,318 ~Howard); 4,598~112 ~Howard); 4,786~696 (Bohnel); DE 3,544~882 Al (Nichiban); 4,645,783 ~Kinoshita); and 4,656,218 (K;n~C~ ) Such solid, acrylate tacky I uD~h~. ~ are typically the suspension POIJIII~ aL;U~I products of acrylate or .~' esters and free radicaliy .~u".,lJ..,~ alle polar monomers. These I
q ~ ! r'~ Q - ~
WOg~i/01281 1~ C r~.,~,.. . ~ ~
pu~ are performed in the presence of a variety of emulsifiers, surfactants, stabilizers and/or under particular process conditions which induce the formation and prevent the __' ofthe spheres.
HQIIOW, polymeric, acrylate, inherentiy tacky, infilsible, solvent-S insoluble, sol~ Jk~ elastomeric pressure-sensitive adhesive ~u~,~u~ ,s having diameters of at least about one ...;wu..._tc, have been described in U.S. Patent Nos. 5,045,569 (De1gadol and 4,988,567 (Delgado). Delgado teaches that small amounts of a high Tg vinyl ester such as vinyl acetate can be used in the c~ . ~1- .- ;.
provided that the resultant po}ymer inas a Tg below -20 C. Preferred hollow 1O IIU~ r,:~ contain one or more interior voids having diameters at least I OO/G of the hoiiow ...;_. " ' ~D. The pressure-sensitive adhesives based on the hollow ~--;.,-u ",h.,.~.i, show reduced or even eliminated adhesive transfer in ~U~ U~ with pressure-sensitive adhesives which are based on solid ~..;.,.uD~,h_.ca. The disclosed llu~,lu~L~ a are useful as ~'1'~~ pressure-sensitive adhesives and in 15 r~,o~ spray pressure-sensitive adhesive .u--~ U.S. Pat. No.
5,053,436 (I:)elgadol and U.S. Pat. No. 3,691,141 ~Silver et al.) both respectively disclose spray pressure sensitive adhesives using solid and hollow acrylates ~u~ u~l._.~.
Othcr than vinyl acetate, vinyl esters have found limited use in prossure-20 sensitive adhesive r ."" ~ - U .~ Examples of non-...;~,~ u~!h~. ~ pressure-sensitive adhesives containing vinyl esters include U.S. Patent Nos. 3,751,449 (&obran et ai.);
4,296,017 (E irll~lcPrlPr et al); and 3,519,587 (Bergmeister et al.). In general, such vinyi esters are not used due to their lack of availability, high cost and poor rate of reactivity and slow PVIJ~ ;OII under free radical conditions when compared to 25 acrylate, l,, Ih..~,lyl~, and maleate esters. In addition, the polymers prepared therefronn are hJd~uly ' '1~ less stable than acrylic polymers. For these reasons vinyl esters have not been specifically utilized as major ~ ~1 ~o 1 ~ in tacky, cl~stu,,,~, ic ~w 2~917~2.
o g610l28l . ~ 5 Summan of the Invention A need, thus, exists for new classes of tacky ~ based upon different monomer systems. This invention provides tacky, polymeric, organic solvent-insoluble, el~tu...~,.;.,, vinyl ester containing pressure-sensitive adhesive l~ lUD~Jh_ 5 typically having diameters of at least about one ...:_. u..._tv. . In addition, the ~ ~ , ' ~ ofthe invention are organic solvent swellable. These ~-.;.,.u~ ;. are useful as .~ pressure-sensitive adhesives.
The present invention also provides pressure-sensitive adhesives comprising these u~ . More specifically, these inherently tacky, polymeric, organic ~ul~ hle, e~u, - . pressure sensitive adhesive ~ù~,~o~
comprise:
a (co)polymer having a Tg of less than abûut -10 C comprising the pol~ - product of:
(a~ about 50 to about 100 percent by weight of at least one free radically pol~ iL~I/Iv monomer comprising vinyl ester monomers wherein a polymer prepared from the monomers have a Tg of less than about -10 C; and (b) about 0 to about 20 percent by weight of at least one polar monomer ~,u~,vl.~ iL~blc with the monomer of element (a) and monomer of etement (c) if included; and 2û lc) about 0 to about 50 percent by weight of a nonpolar free radically pul l ' ' vinyl monomer, cupol ~ ablc with the monomer of element (a) and element (b), if included wherein the weight pc. ~,~.-t.~ of (a), (b) and (c), are based upon the total weight of the (co)polymer; and (d) about 0 to about 0.15 equivalent weight percent to a 25 ~ .IUS ;li~ hlQ agent based upon the total weight of the monomers plus the ~,.o~ i..g agent.
Preferably the copolymer referred to above consists essentially of (a), (b)7 (c)and (d), and most preferably consists of (a), (b), (c), and (d).
Field of thc Invention This invention relates to tacky, polymeric, organic solvent-insoluble, , pressure-sensitive adhesive l/~lUD,~Jh~ , prepared from vinyl ester monomers, to processes for their p~ a~liu~, and to their use as pressure-sensitive 10 adhesives.
Background of the Invention Tacky, ~laaLul~ uli~.~valJh~ are known to be useful in ~I r ~ - ~ I pressure-sensitive adhesive a, r As used herein, the term 15 ~I~r - ~ I N refers to the ability to be repeatedly adhered to and removed from a subdrate without substantial loss of zdhesion capability. i ' ua~ based adhesives are thought to perform well in such arr~ ' at least in part due to their "b.,L''~:' ' ,,1' character, wherein substrate, tend to be pushed aside and trapped between the ,. i-,. UD~ as the adhesive is applied. Upon removal, the 20 adhesive can then still present a relatively ., ~ Prl surfiace for ~ ;. " to the substrate.
Numerous references concern the l/lel.l.~ldLiOI'I and/or use of inherently tscky, ela.DtUlll~ acrylate polymeric ,..;.,.u .~ which are solid in nature The Liol. and uses of such Ill;~,l ualJh~ , along with their p ,~
25 prûperties~ are disclosed in U.S. Pat. Nos. 3~691~140 (Silver~; 4~166~152 (Baker et al.);
4,495,318 ~Howard); 4,598~112 ~Howard); 4,786~696 (Bohnel); DE 3,544~882 Al (Nichiban); 4,645,783 ~Kinoshita); and 4,656,218 (K;n~C~ ) Such solid, acrylate tacky I uD~h~. ~ are typically the suspension POIJIII~ aL;U~I products of acrylate or .~' esters and free radicaliy .~u".,lJ..,~ alle polar monomers. These I
q ~ ! r'~ Q - ~
WOg~i/01281 1~ C r~.,~,.. . ~ ~
pu~ are performed in the presence of a variety of emulsifiers, surfactants, stabilizers and/or under particular process conditions which induce the formation and prevent the __' ofthe spheres.
HQIIOW, polymeric, acrylate, inherentiy tacky, infilsible, solvent-S insoluble, sol~ Jk~ elastomeric pressure-sensitive adhesive ~u~,~u~ ,s having diameters of at least about one ...;wu..._tc, have been described in U.S. Patent Nos. 5,045,569 (De1gadol and 4,988,567 (Delgado). Delgado teaches that small amounts of a high Tg vinyl ester such as vinyl acetate can be used in the c~ . ~1- .- ;.
provided that the resultant po}ymer inas a Tg below -20 C. Preferred hollow 1O IIU~ r,:~ contain one or more interior voids having diameters at least I OO/G of the hoiiow ...;_. " ' ~D. The pressure-sensitive adhesives based on the hollow ~--;.,-u ",h.,.~.i, show reduced or even eliminated adhesive transfer in ~U~ U~ with pressure-sensitive adhesives which are based on solid ~..;.,.uD~,h_.ca. The disclosed llu~,lu~L~ a are useful as ~'1'~~ pressure-sensitive adhesives and in 15 r~,o~ spray pressure-sensitive adhesive .u--~ U.S. Pat. No.
5,053,436 (I:)elgadol and U.S. Pat. No. 3,691,141 ~Silver et al.) both respectively disclose spray pressure sensitive adhesives using solid and hollow acrylates ~u~ u~l._.~.
Othcr than vinyl acetate, vinyl esters have found limited use in prossure-20 sensitive adhesive r ."" ~ - U .~ Examples of non-...;~,~ u~!h~. ~ pressure-sensitive adhesives containing vinyl esters include U.S. Patent Nos. 3,751,449 (&obran et ai.);
4,296,017 (E irll~lcPrlPr et al); and 3,519,587 (Bergmeister et al.). In general, such vinyi esters are not used due to their lack of availability, high cost and poor rate of reactivity and slow PVIJ~ ;OII under free radical conditions when compared to 25 acrylate, l,, Ih..~,lyl~, and maleate esters. In addition, the polymers prepared therefronn are hJd~uly ' '1~ less stable than acrylic polymers. For these reasons vinyl esters have not been specifically utilized as major ~ ~1 ~o 1 ~ in tacky, cl~stu,,,~, ic ~w 2~917~2.
o g610l28l . ~ 5 Summan of the Invention A need, thus, exists for new classes of tacky ~ based upon different monomer systems. This invention provides tacky, polymeric, organic solvent-insoluble, el~tu...~,.;.,, vinyl ester containing pressure-sensitive adhesive l~ lUD~Jh_ 5 typically having diameters of at least about one ...:_. u..._tv. . In addition, the ~ ~ , ' ~ ofthe invention are organic solvent swellable. These ~-.;.,.u~ ;. are useful as .~ pressure-sensitive adhesives.
The present invention also provides pressure-sensitive adhesives comprising these u~ . More specifically, these inherently tacky, polymeric, organic ~ul~ hle, e~u, - . pressure sensitive adhesive ~ù~,~o~
comprise:
a (co)polymer having a Tg of less than abûut -10 C comprising the pol~ - product of:
(a~ about 50 to about 100 percent by weight of at least one free radically pol~ iL~I/Iv monomer comprising vinyl ester monomers wherein a polymer prepared from the monomers have a Tg of less than about -10 C; and (b) about 0 to about 20 percent by weight of at least one polar monomer ~,u~,vl.~ iL~blc with the monomer of element (a) and monomer of etement (c) if included; and 2û lc) about 0 to about 50 percent by weight of a nonpolar free radically pul l ' ' vinyl monomer, cupol ~ ablc with the monomer of element (a) and element (b), if included wherein the weight pc. ~,~.-t.~ of (a), (b) and (c), are based upon the total weight of the (co)polymer; and (d) about 0 to about 0.15 equivalent weight percent to a 25 ~ .IUS ;li~ hlQ agent based upon the total weight of the monomers plus the ~,.o~ i..g agent.
Preferably the copolymer referred to above consists essentially of (a), (b)7 (c)and (d), and most preferably consists of (a), (b), (c), and (d).
2 ~ g i ~ 5 ~
W0 96/012X] 1~
Preferably the pressure sensitive adhesive uu~ .v~ consist essentially of said ~rUl ...~ t;,~ ~rl copolymers, most preferably consists of said aru,~ ' ~,u~v.) .
The invention also provides for u~h~o ofthis invention which are S hollow, ..,.~. v~JL~ ~J of this invention which are solid, methûds of making these ."i.,. , ' ~," aqueûus ~ and solvent dispersions ofthese mi~,~u~h.,~, spray l~ k pressure-sensitive adhesive ~u .l.r,~:l;o s, and ...;.,." ~. cûated sheet materiais. When hollow, preferred hûllow n.;~.. uaiJh~.~ c~ contain one or mose interior voids having diameters at least 10~/~ of the hollow v~,uL,. ~,~,. The lû ...;.... ,' ~.oftheinventionhaveaglasstransition., ~.~u~c(Tg~oflessthan about -10~C, preferably about -100~C to about -20~C. If the glass transitiûn tt,..~ lu.c ûfthe lll;.,lu~ ,c~ rises abûve -10~C, then the ~ u~l~h~t~ will havereduced tack and elasticity.
Aqueous ~ v ~; ûf hûllow ,..;~ ." ~ J may be prepared by a 15 two-step ' " process comprising the steps Or:
(a) forming a water-in-ûil emulsion by combining ~ij an Aqueous Phase I comprising water and, optionally, at least one free radically tJVl~..,~, ;~I,ll polar monomer; with (;i) an Oil Phase II compris;ng at least one free rzdically POIJ..~ ,Ie vinyl estcr monomer, an emulsifer having an HLB valuc o~below about 7, optionally at 20 lezst one free radically pol.7...~ .1,1e nonpolar vinyl monomer wherein a polymer prepared from all the monomers would have a Tg of less than about -10~C, and optionally at least one ~ ;r ~;o ~ u~liuk;--6 agent;
~ b) forming a water-in-oil-in-water emulsion by dispersing the water-in-oil emulsion into an Aqueous Phase 11 comprising water and an emulsifier 25 having a hydrophilic-lipophilic balance value of at least about 6; and (c) initiating pol~ ;v.,, wherein all ur part, if used, of the polar monomer(s) znd/or nonpolar monomer(s) and/or ~,~u~lh-Li..6 agent(s) is alternatively added to the water-in-oil-in-water emuls;on after POIJ~ ;UII of the water-in-oil-in-water ~" 21917~2 o 96/01281 emulsion is initiated, but before 100% to conversion to polymer ot the monomer~ u.
said water-in-o~ . emulsion occurs.
Aqueous ~ of hollow u~,l..,..,s which may contain polar monomer(s) may also be prepared by a simpler ("one-step") . ' ~~ process S comprising the steps of:
(a) forming droplets by mixing in any order together (i) at least one free radically pol~ iLabl~, vinyl ester monomer, wherein a polymer prepared from the monomer(s) would have a Tg of less than about -lO C;
(ii) optionally at least one free radically pol~ . iL~blc polar monomer;
(iii) optionally st least one free radically pul~ iLablc nonpolar vinyl monomer, and (iv) at least one emulsifier which is capable of forming a 15 water-in-oii emulsion inside the droplets, the emulsion being ~ ' '~ ~'1~, stable during e ' ~~ ~ and pcl~ ,. iLaliull~
(v) an aqueous medium; and, (vi) optionally at least one rn~ ifi ~ U~C~ g agent;
and (b) initiating pUlJ~ iLI~iUn.
Aqueous ~ J - of hollow ll~icl ~ may also be prepared by a r- - " ~ of the "one-step" ,~ process comprising the steps of:
(a) forming droplets by mixing together (i) at least one free radically polymerizable vinyl ester 25 monomer, wherein a polymer prepared from the monomer(s) would have a Tg of less than about -10 C, (ii) optionally a portion of, if used, of at least one free radically pol~ iLab'c polar monomer;
21917$2 wo 96/012~
(iii) optionally a portion, if used, of at least one free radically pul~ nonpolar vinyl monomer;
(iv) at least one emulsifier which is capable of forming a water-in-oil emulsion inside the droplets, the emulsion being ~ul~D~ ti..lly stable during _ ' ' and pul.~ ;r~'l, and (v) an aqueous medium; and (vi) optionally at least one ml~'nr~ o.luD~ hi.. ~; agent, and (b) initiatingpol~ AS;,,,~ and, (c) adding all or the remaining port;on of polar monomer(s) and/or nonpolar monomers, if used, or a portion of the .~;r ,~ agent, if used, prior to the 100% conversion of the monomer(s) contained in the droplets.
Aqueous ~ ci~ - of solid .,.;."u~ , c~ may be prepared by an anaiogous Uone-stepn ,"..~ li.,.. process comprising the steps of:
(a) forming dropiets by mixing together:
(i) at least one free radically pc,l~ i~l~ vinyl ester monomer, wherein a polymer prepared from the monomer would have a Tg of le.ss than about -10 C, (ii) optionally at least one free radically pU~ dlil~ polar 20 monomer;
~,ii3 optionally at least one free radically pUI,yll.~,.i.:d nonpolar vinyl monomer;
(iv) at least one suspension stabilizer;
(v) an aqueous medium; and (vi) optionaily at least one ~ u~ g agent;
(b) initiating p~ .i~liùn, and (c) adding all or any remaining portion of optional polar monomer(s) and all or the remaining portion of nonpolar monomer, if used, and adding 2191~752 O 9fi/01281 p~ ~
all or any remaining portion of the ' ~ ' ' ,, agent prior to the l oOo/o conversion of the monomer contained in the droplels.
Aqueous ~ of solid ".;~,u~ s may be prepared by a "one-step" ~ process comprising the steps of:
(a) forming droplets by mixing together:
(i) at least one free radically pG~ iLllbl~ vinyl ester monomer, wherein a polymer prepared from the monorner would have a Tg of less than about -10~C, (ii) optionally at least one free radically p~ l iLal~le 10 nonpolar monomer;
(iii~ at least one emulsifier having a h,d,~ ';,.u~l.il;., baiance value of less than about 25;
(iv) an aqueous medium; and (v) optionally at least one ,II ;r ",. .~ .,I U .~lhlkillg agent;
(b) initiating pol~l.. ,.iLaliull; and (c) adding all or any remaining portion of nonpolar monomer(s), if used, and all or any remaining portion of ,,...I~;r.,,.. n~ -' crosslinker, if used, prior to the 100% conversion ofthe monomer contained in the droplets.
The following terms have these meanings as used herein:
1. The term "droplet" means the liquid stage of the ,.... ;~,. u~h~
prior to the completion of pol~
2. The term "cavity" means a space within the walls of a droplet or " ' e when still in the suspension or dispersion medium prior to drying, and thus containing whatever medium was used.
W0 96/012X] 1~
Preferably the pressure sensitive adhesive uu~ .v~ consist essentially of said ~rUl ...~ t;,~ ~rl copolymers, most preferably consists of said aru,~ ' ~,u~v.) .
The invention also provides for u~h~o ofthis invention which are S hollow, ..,.~. v~JL~ ~J of this invention which are solid, methûds of making these ."i.,. , ' ~," aqueûus ~ and solvent dispersions ofthese mi~,~u~h.,~, spray l~ k pressure-sensitive adhesive ~u .l.r,~:l;o s, and ...;.,." ~. cûated sheet materiais. When hollow, preferred hûllow n.;~.. uaiJh~.~ c~ contain one or mose interior voids having diameters at least 10~/~ of the hollow v~,uL,. ~,~,. The lû ...;.... ,' ~.oftheinventionhaveaglasstransition., ~.~u~c(Tg~oflessthan about -10~C, preferably about -100~C to about -20~C. If the glass transitiûn tt,..~ lu.c ûfthe lll;.,lu~ ,c~ rises abûve -10~C, then the ~ u~l~h~t~ will havereduced tack and elasticity.
Aqueous ~ v ~; ûf hûllow ,..;~ ." ~ J may be prepared by a 15 two-step ' " process comprising the steps Or:
(a) forming a water-in-ûil emulsion by combining ~ij an Aqueous Phase I comprising water and, optionally, at least one free radically tJVl~..,~, ;~I,ll polar monomer; with (;i) an Oil Phase II compris;ng at least one free rzdically POIJ..~ ,Ie vinyl estcr monomer, an emulsifer having an HLB valuc o~below about 7, optionally at 20 lezst one free radically pol.7...~ .1,1e nonpolar vinyl monomer wherein a polymer prepared from all the monomers would have a Tg of less than about -10~C, and optionally at least one ~ ;r ~;o ~ u~liuk;--6 agent;
~ b) forming a water-in-oil-in-water emulsion by dispersing the water-in-oil emulsion into an Aqueous Phase 11 comprising water and an emulsifier 25 having a hydrophilic-lipophilic balance value of at least about 6; and (c) initiating pol~ ;v.,, wherein all ur part, if used, of the polar monomer(s) znd/or nonpolar monomer(s) and/or ~,~u~lh-Li..6 agent(s) is alternatively added to the water-in-oil-in-water emuls;on after POIJ~ ;UII of the water-in-oil-in-water ~" 21917~2 o 96/01281 emulsion is initiated, but before 100% to conversion to polymer ot the monomer~ u.
said water-in-o~ . emulsion occurs.
Aqueous ~ of hollow u~,l..,..,s which may contain polar monomer(s) may also be prepared by a simpler ("one-step") . ' ~~ process S comprising the steps of:
(a) forming droplets by mixing in any order together (i) at least one free radically pol~ iLabl~, vinyl ester monomer, wherein a polymer prepared from the monomer(s) would have a Tg of less than about -lO C;
(ii) optionally at least one free radically pol~ . iL~blc polar monomer;
(iii) optionally st least one free radically pul~ iLablc nonpolar vinyl monomer, and (iv) at least one emulsifier which is capable of forming a 15 water-in-oii emulsion inside the droplets, the emulsion being ~ ' '~ ~'1~, stable during e ' ~~ ~ and pcl~ ,. iLaliull~
(v) an aqueous medium; and, (vi) optionally at least one rn~ ifi ~ U~C~ g agent;
and (b) initiating pUlJ~ iLI~iUn.
Aqueous ~ J - of hollow ll~icl ~ may also be prepared by a r- - " ~ of the "one-step" ,~ process comprising the steps of:
(a) forming droplets by mixing together (i) at least one free radically polymerizable vinyl ester 25 monomer, wherein a polymer prepared from the monomer(s) would have a Tg of less than about -10 C, (ii) optionally a portion of, if used, of at least one free radically pol~ iLab'c polar monomer;
21917$2 wo 96/012~
(iii) optionally a portion, if used, of at least one free radically pul~ nonpolar vinyl monomer;
(iv) at least one emulsifier which is capable of forming a water-in-oil emulsion inside the droplets, the emulsion being ~ul~D~ ti..lly stable during _ ' ' and pul.~ ;r~'l, and (v) an aqueous medium; and (vi) optionally at least one ml~'nr~ o.luD~ hi.. ~; agent, and (b) initiatingpol~ AS;,,,~ and, (c) adding all or the remaining port;on of polar monomer(s) and/or nonpolar monomers, if used, or a portion of the .~;r ,~ agent, if used, prior to the 100% conversion of the monomer(s) contained in the droplets.
Aqueous ~ ci~ - of solid .,.;."u~ , c~ may be prepared by an anaiogous Uone-stepn ,"..~ li.,.. process comprising the steps of:
(a) forming dropiets by mixing together:
(i) at least one free radically pc,l~ i~l~ vinyl ester monomer, wherein a polymer prepared from the monomer would have a Tg of le.ss than about -10 C, (ii) optionally at least one free radically pU~ dlil~ polar 20 monomer;
~,ii3 optionally at least one free radically pUI,yll.~,.i.:d nonpolar vinyl monomer;
(iv) at least one suspension stabilizer;
(v) an aqueous medium; and (vi) optionaily at least one ~ u~ g agent;
(b) initiating p~ .i~liùn, and (c) adding all or any remaining portion of optional polar monomer(s) and all or the remaining portion of nonpolar monomer, if used, and adding 2191~752 O 9fi/01281 p~ ~
all or any remaining portion of the ' ~ ' ' ,, agent prior to the l oOo/o conversion of the monomer contained in the droplels.
Aqueous ~ of solid ".;~,u~ s may be prepared by a "one-step" ~ process comprising the steps of:
(a) forming droplets by mixing together:
(i) at least one free radically pG~ iLllbl~ vinyl ester monomer, wherein a polymer prepared from the monorner would have a Tg of less than about -10~C, (ii) optionally at least one free radically p~ l iLal~le 10 nonpolar monomer;
(iii~ at least one emulsifier having a h,d,~ ';,.u~l.il;., baiance value of less than about 25;
(iv) an aqueous medium; and (v) optionally at least one ,II ;r ",. .~ .,I U .~lhlkillg agent;
(b) initiating pol~l.. ,.iLaliull; and (c) adding all or any remaining portion of nonpolar monomer(s), if used, and all or any remaining portion of ,,...I~;r.,,.. n~ -' crosslinker, if used, prior to the 100% conversion ofthe monomer contained in the droplets.
The following terms have these meanings as used herein:
1. The term "droplet" means the liquid stage of the ,.... ;~,. u~h~
prior to the completion of pol~
2. The term "cavity" means a space within the walls of a droplet or " ' e when still in the suspension or dispersion medium prior to drying, and thus containing whatever medium was used.
3. The term Hvoid" means an empty space completely within the waiis of a pol.~ ,,u~,he.~;.
4. The term "hollow" means containing at least one void or cavity.
S. The term "solid" means not hollow; that is, void-free or cavity-firee.
2 1 ~ .~ 7 ~
wos~6rO12#~ I.,,.h.
6. The term "~ ' ~ " has been described, for example, as, "...
applying to amorphous or non-crystalline materials that can be stretched to at leas~
twice their original length and which will retract rapidly and forcibly to ' '1!~
their original dimensions upon release ofthe force." [S.L. Rosen, r~ ~a~
S. The term "solid" means not hollow; that is, void-free or cavity-firee.
2 1 ~ .~ 7 ~
wos~6rO12#~ I.,,.h.
6. The term "~ ' ~ " has been described, for example, as, "...
applying to amorphous or non-crystalline materials that can be stretched to at leas~
twice their original length and which will retract rapidly and forcibly to ' '1!~
their original dimensions upon release ofthe force." [S.L. Rosen, r~ ~a~
5 Prin~ oc of Polymeric: ~ ' Wiley: New Yoric p. 314 (1982)1 7. The term "organic solvent-insolubie" in reference to a polymeric materiai refers to a polymeric material which is not totally dissolved on a molecular level in common organic solvents.
8. The term "solvent sweliablcU in reference to a polymeric material 10 refers to a polymeric material that swells in solvent to an extent larger than its original dimension and forms a dispersion consisting, sllhct~nt~ y~ of individual particles.
All percents, parts, ratios, etc. described herein are by weight unless indicated otherwise.
15 Detailed Description of the Inv~ ntinn Free Radically rul~ h Ir Vinyl ~ster Monomers Useful ester monomers are oleophilic, water .,....,I~:r ~-lr, have restricted water solubility (less than about Iglper lOOg of water at 25~C), and as hu~uopul r 20 generally have glass transition t~ UIt:~ below about -] 0~C.
Vinyl ester monomers useful according to the invention are those of the general formula:
O
25 CH2=C{) C--CH2-R
iH
wherein Rl is selected from the group consisting of linear or branched 30 alicyl groups having I to 12 carbon atoms. Such vinyl esters include hut are not limited to those selected from the group consisting of vinyl 2-~LLJ:h~d~lodl~ vinyl caprate, s 219.1752 vinyl laurate, vinyi F ' ~uuat~" vinyl hexanoate, vinyl ,~"o~ ' - vinyl decanoate, vinyl octanoate, and other ~ ' u..~alul aLed vinyi esters of linear or branched carboxylic acids comprising 3 to 14 carbon atoms which as l~u~upu'r~
have glass transition tcl.liJ.,.alulc~ below about -10~C. Preferred vinyl ester monomers 5 include those selected from the group consisting of vinyl laurate, vinyl caprate, vinyl-2-cli..~" , and mixtures thereof.
Additionaily, u.~.' Ii~ ' - and phenyalkyl-substituted vinyl esters, such as those described in U.S. Patent No. 3,751,449 (Gobran et al.) having the formula set fonh i ' ' '~ below, can also be used in the ...i~. u~,h.,. .~O of the 10 present invention.
o R2 Il I .
CH2=CH (}C--CH--R3 where R2 is a ~iy~,loal;~vlldti~, or aromatic group (e.g., phenyl~, and R3 is a hydrogen atom or lower alkyl (e.g., with I to 6 carbon atoms).
Free Radically Pol~ iLaiJh, Polar Monomers The free radically pul~ .iL..iJl~, polar monomers useful in the present 20 invention are both somewhat oii-soluble and water-soiuble, resulting in a distribution of the polar monomer between the aqueous and the oil phases.
Representative examples of suitable polar monomers include but are not iimited to those seiected from the group consisting of acrylic acid, Ill~.~ha~,l yl;~. acidl itaconic acid, crotonic acid, maleic acid, fumaric acid, sulfoethyl ~..~,lI.a~,.yl..le, N-vinyi 25 ~ ,i; ione, N-vinyl Cal)lUla~.lalll~ 2-vinyl-4,4-dimethyl-2- ' ' e, t-butyl acrylamide, dimethyl amino ethyl acrylamide, N-octyl acryiamide, and ionic monomers such as sodium ~ lhaw~ylale~ ammonium acrylate, sodium acrylate, L~ L~...;..e p-vinyi benzimide, 4,4,9-l- i.,.elhji 1 azonia-7-oxo-8-oxa-dec-9-ene- 1 -sulphonate, N,N~ ' N (beta ...~ e~ yloxy-ethyl) ammonium propionate betaine, 30 1.i....lh,' ' - ll~ la~.l yL..kie~ I,I-dimethyl-1-(2,3-dihydroxypropyl)amine g 2 ~ S ~ ' WO 96101281 I ~
' ~" "e, mixtures thereof, and the like. Preferred polar monomers include thoseselectedfromthegroupconsistingof l ~OGI r ~ unoc,llu..~ acids, ~ r ~ di~ ui~yl;l, ncids, a.,- ~' ' , N-substituted a~ ' ' , salts thereof,and mixtures thereo~ Examples of such preferred polar monomers include but are not 5 limited to those selected from the group consisting of acrylic acid, sodium acrylate, N-vinyl ~ ul;dollc, and mixtures thereof.
Free Radically rcl~ .,..";GalJI~ Nonpolar Vinyl Monomers Free radically pùl~....,~'~blc nonpolar vinyl monomers which, as 10 hUII~"JU~ , have glass transition t~,lU~,. alw~,~ higher than about -10~C, e.g., tert-butyl acrylate, isoborn,vl acrylate, butyl methacrylate, vinyl acetate, ac,~l~ ilc, mixtures thereof, and the like, may optionally be utilized in ~u.~ iuu with ûne or moreofthevinylestermonomersprovidedthattheglasstransitiont~a~ Lulcofthe resultant copolyrner is below about -10~C.
Similarly, other free radically pOl~ ablc~ nonpolar vinyl monomers which, as humupulJu~ have glass transition Ltlll~ aLul~" lower than about -10~C,such as alkyl acrylate and lu.,Ll~.,lylah monomers, are useful in preparing the u.;~.. l , ' u.. and pressure-sensitive adhesives of this invention. Such alkyl acrylate and ' yht~ monomers are those ".. s'.. ~ l Ull~aLul~lled acrylate an 1 20 ~ h~ yldtt ester~ of non-tertiary alkyl alcohols, the alkyl groups of which preferably have from about 4 to about 14 carbon atoms. Examples of such monomers include but are not limited to those selected from the group consisting of isooctyl acrylate, 4-methyl-2-pentyl acrylate, 2-methylbutyl acrylate, isoamyl acrylate, sec-butyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, isodecyl l~ e~ isononyl acrylate,25 isodecyl acrylate, and mixtures thereof.
Preferred acrylate monomers include those selected from the group consisting of isooctyl acrylate, isononyl acrylate, isûamyl acrylate, isodecyl acrylate~
2-ethylhexyl acrylate, n-butyl acrylate, sec-butyl acrylate, and mixtures thereof 21917fii2 0 96/01281 PCT/USg!;~08215 ('~ R
The . , ' .,.. of this invention and the pressure-sensitive adhesives made therefrom comprise a copolymer comprising about 50 to about 100 percent by weight of at least one free radically p~ iJIe vinyl ester monomer; optionally, 5 about 0 to about 20 percent by weight of one or more polar monomers, (typically about 0.1 to about 20 percent, if included); and optionally about 0 to about 50 weight percent of a nonpolar free radicaily cu~,ul ~ ....,. ;~vl~ vinyl monomer (typically about 0.1 to about 50 percent by weight, if included), based upon the total weight of the copolymer.
Preferably, the pressure-sensitive adhesive Ul;~"U .~uI,c.~ comprise a 10 copolymer comprising about 60 to about 100 percent by weight offree radicallyPOI~ ;L~IIWC vinyl ester monomer; optionally, about 0 to about 15 percent by weight of at least one polar monomer (typically about 0.1 to about 15 percent, if included);
and optionally about 0 to about 30 weight of nonpolar free radically ~,o~Jvlrl~
vinyl monomer (typically about 0.1 to about 30 percent, if included) based upon the 15 total weight ofthe copolymer. Most preferably, the pressure-sensitive adhesive ~ u~h~o comprise a copolymer comprising about 70 to about 100 percent by weight of free radically pUirU~ iLl~iJI~ vinyl ester monomer; optionally about 0 to about 10 percent by weight of polar monomer (typically about û. I to about 10 percent by weight, if included), and optionally about 0 to about 20 percent (typically about 0.1 to 20 about 20 percent by weight, if included) by weight of nonpolar free radicallycu~,ul~ ' ' vinyl monomer, based upon the total weight of the copolymer.
Preferably, at least one polar monomer is included in the c ~ o~:l;u~
but l~lh~lV~ o may also be prepared using free radically pul.~."~.i~l,lc vinyl ester monomer(s) alone or without a polar monomer in ~.u .1. - ;o n only with other free 25 radically pul~ i~bic nonpolar vinyi monomers, such as isooctyl acrylate, vinyl acetate, etc. Most preferably, at least about I percent to about 10 percent by weight polar monomer is included as this ratio provides ...;.,,u~l,L.~ with balanced pressure-sensitive adhesive properties.
~1917$~2~ ~
~, W096fO1281 I~,1/~J.. ,_,~ ' ~
Two-Step ~Pth~l of Preparin~ Hollow Mi~
Aqueous a ~ of the hollow Illi~,luslJh.,.~O of the invention may be prepared by a "two-step" ' '~ process which first involves forming a water-in-oil emulsion of an aqueous solution of water and, if used, polar monomer(s), 5 in the oil phzse monomer ~i.e., at least vinyl ester monomer and optional nonpolar monomer), using an emulsifier having a low hydrophilic-lipophilic balancc ~HLB) value.
Where it is desirable not to include a polar monomer, an ar~ueous phase may be mixed directly with the oil phase monomer ~I.e., vinyl ester monomer and optional nonpolar monomer~, and emulsifier to form the water-in-oil emulsion.
Thehollow",w,' '~ ofthe ~ caOftheinventioncanbe determined through the choice of emulsifiers used in this "two-step~ process. Suitable emulsifiers for the use in the first step of the two step preparation of hollow ~.i.,l., ' ~O are those having HLB values below about 7, preferably in the range of about 2 to about 7. Examples of such emulsifiers include but are not limited to those 15 selected from the group consisting of sorbitan r~onnole~P~ sorbitan trioleate, ethoxylated oleyl alcohol ~such as Brij 93, available from Atlas Chemical Industries, Inc.), and mixtures thereof. It is noted that if a two-step method is followed in which the water-in-oil-in-water emulsion is unstable, solid m.~,u2,~ could result.
In the first step for preparing hollow ~I;W~ S~, oil phase 20 monomer~s), emulsifier, a free radical initiator, and optional wuOs r.l~ p monomer or monomers as defined below are combined, and an aqueous solution comprising waterand, if used, polar monomer~s) is agitated and poured into the oil phase mixture to form a water-in-oil emulsion. A thickening agent, such as methyl cellulose, may also be included in the aqueous phase of the water-in-oil emulsion. In the second step, a 25 water-in-oil-in-water emulsion is formed by dispersing the water-in-oil emulsion of the first step into an aqueDUs phase containing an emulsifier having an HLB vahle above about 6. Examples of such emulsifiers include but are not limited to those selected from the group consisting of ethoxylated sorbitan ~ ,ol~ , ethoxylated lauryl alcohol, alkyl sulfates1 and mixtures thereof. In both steps, when an emulsifier is ~w 21917~2 o 961012X1 r~
utilized, its . ~ ~ u ~ should be greater than its critical micelle ~u~ iull, which is herein defined as the minimum ru ~ of emulsifier necessary for theformation of micelles, i.e., sul,...;_, ua~,u~ &e,~ 1LiUIla of emulsifier molecules.
Critical miceUe; is slightly different for each emulsifier, usable 5 ~,.. ..S.~ ranging from about 1.0 x 10-4 to about 3.0 moles/liter. The final process step of the method of the invention involves ~he application of heat or radiation (such as ultraviolet radiation, etc.) to initiate PU~ ;L~I;OI~ of the monomers. One skilled in the art would be able to select an appropriate amount of heat and/or radiation depending on the initiator selected.
One-Step Method of Preparing Hollow M;_~ ua~Jh~
Aqueous s~ of hollow ~ u~L~.l ta which may contain polar monomer(s) may also be prepared by a ~one-step" ~ n process comprising aqueous suspension pol~ ."iL~liu.l of at least one vinyl ester monomer and optional 15 nonpolar monomer and, optionally, at least one polar monomer in the presence of at least one emulsifier capable of producing a water-in-oil emulsion inside the droplets which is ' "~ stable during e - ~ I ;r~n and pGI~ iLaLion. As in the two-step ~ ;. -,i. . process, the emutsifier is utilized in ~u..c~..L-~Lu,.. greater than its critical micelle ~ In general, emulsifiers formulated at this 20 c~.u - ~.,u..~ will produce stable cavity-containing droplets during the pUlJ. ;LllliUII, and are suitable for use in this one-step process. Examples of such emulsifiers include but are not limited to those selected from the group consisting Of.dk~;al~ . sulfates ~ such as sodium alkylarylether sulfate, e.g., Triton W/30, available from Rohm and Haas; " YI~I~IL~UIY~Ih~I sulfates such as alkylarylpoly~ethylene oxide) sulfates; alkyl 25 sulfates such as sodium lauryl sulfate, ammonium lauryl sulfate, 1,; I I -'~tA.1 ''~ lauryl sulfate, and sodium hexadecyl sulfate; alkyl ether sulfates such as ammonium lauryl ether sulfate, and alk~l~,olJ~LL, sulfates such as alkyl poly(ethylene oxide) sulfates;
~ ' yl.llyl~/ùl~Lh~. sulfonates such as alkylarylpoly(ethylene oxide~ sodium sulfonate (e.g., Triton X-200, co..,."~ lly available from the Rohm and Haas Co.j; alkyl - '2I9~752 WO 96/01281 I ~
benzene sulfonates such dS sodium p dod.c)'b~,.~..e sulfonate (e.g., Siponate DS -10, '1~ available from Alcolac, Inc.); alkyl ~ r~ t~ ~, such as Aerosol OT, a dioctyl ester of sodium SL~r ' ' acid ~,U-~ ,;ully available from American Cyanamid Process Chemicals Dept.; and mixtures thereof. Emulsifiers selected from 5 the group consisting of alkyl sulfates, all~yl ether sulfates, _L'.ylu. ~ I~,.h~ . sulfates, and mi~;tures thereof are preferred as they provide a maximum void volume per ".1.., . , ~; for a minimum amount of surfactant. Nonionic emulsifiers, e.g. Siponic Y-500-70 ~eLLu~' d oleyl alcohol, .,u--....~ ly available from Alcolac, Inc.) and Pluror;tc P103 (block copolymer of polypropylene oxide and pul~.,LLJI~ ,le oxide]O UIll,ll~ lly available form BASF Corporation), can also be utilized alonc or in with anionic emulsifiers, and mixtures thercof. Polymeric stabilizers may also be present but are not necessary.
One-SteD Method of Preparing Solid Miulua~Jl.c.l,~
Aqueous ~ J"~ of solid ~ u~Jh., ta may be prepared by a "one-step" ~ process comprising an aqueous suspension pulylll~ uLiull of at least one vinyl ester monomer; at least one polymeric stabiiizer, such as poly(vinyl alcohol~; optionally, at least one polar monomer, optionally, at least one nonpolar monomer, and/or optionally a ...uaal;lll~hlg monomer. It is believed that other polymeric stabilizers, such as those described in U.S. Patent No. 4,166,152 CBaker et al.~ ~e.g., carboxy-mûdified pûl~dC~ , carboxy-modified cellulûses, quaterndry arnine-substituted cellulûses~ etc.), and other steric or electrosteric polymeric stabilizers, including but not limited to those selected from the group consisting of pulyu~J.,.hyli.~c, polyacrylic acid, pul~ hq~ rylic acid, pol~u~"~;ulllide~ polyvillyl 25 ~ polyethylene imine, polyvinyl methyl ether, salts thereof, and mi~:turcs thereof, would also be useful according to the present invention.
It has also been found that aqueous suspension of solid ,..;~"u:,~)h.,.ti, not .l3u-~L;..~ any polar monomer may be prepared by a similar "one-step"
;. . process which h1GUl ,VUI dt~ a emulsifiers having HLB values lower than ~ , 0128~
about 25 rather than polymeric stabilizers in the formation of these ~";~"u~,h_.~,;,.
Examples of emulsifiers having HLB values lower than 25 include but are not limited to those selected from the group consisting of alh~l.,. ~ l,uu~ h~. sulfonates such as ! ~' ylal.~ (ethylene oxide) sodium sulfonate (e.g.,TritonTM X-200,, 5 available from the Rohm and Haas Co.); alkyl benzene sulfonates such as sodium p-dvd-,~,Jlb~ . sulfonate (e.~., PolystepTM Biosoft LAS-50, ~,u"....~ "), available from Alcolac, Inc.); alhyl ~ , such as AerosolTM OT, a dioctyl ester of sodium - ~r ' ' acid co.. ~,.. "~, available from American Cyanamid ProcessChemicals Dept.; and mixtures thereo~
All of these preparative methods may be modified by wilLl,old;.. g the addition of all or part, if used, of the polar monomer(s) and/or nonpolar monomer(s), if used~ and/or ~ ~ -r ' ~ wu~ hi~-g agent, if used, until after polylu~iLalion ofthe water-in-oil-in-water emulsion is initiated. This may be done provided that the withheld ~ o ~ are added to the pol~..,~,. i~i..~ mixture prior to its ] 00%15 conversion of monomers to polymer in the emulsion. This processing flexibility allows the formulator to add any portion of the optional polar monomer(s) and/or optional free radically pvl~ ' ' '- vinyl monomers and/or any portion of the mu~
.,., ~- ' ' ~ agent at any convenient point in preparing the pressure-sensitive adhesive of this invention.
Suitable initiators are those which are normally suitable for free radical pol~ ' of free radically pol.~ l,lc monomers and which are oil-soluble and of very low solubility in water (i.e., typically less than about 1 g per 100g of water at 25 20~C). Examples of such initiators include but are not limited to those selected from the group consisting of thermally-activated initiators such as azo c~ .,l.l,o ....1~, hydlu~.,. u~ id~, peroxides, and the like, and photoinitiators such as t ~ h benzoin ethyl ether, and 2,2-dimethoxy-2-phenyl ~ l .ol e, and the like, and mixtures thereof. Use of a water-soluble pul~ alioll initiator causes formation of 2~91~
wo sc/0l2sl P~rruss~ 2lq substantial amounts of latex. The initiator is generally used in an amount ranging fromabout 0.01 percent up to aboul 10 percent by weight of the total PUI~ GI~(i.e., monomers, and optional ~,lu~al;l~Lhlg agent), preferably up to about 5 percent.
s S~sslin,'cing Agents The CU"'I~'J' I;UI~ from which the ~ f." ' ~a ofthe invention are made mayalsocontaina r....~;r....~ , g agent. Theterm I~.r.. ~;.. =" as used herein refers to wus~ kill~, agents which possess two or more free radically 10 pu~ thJl~ u -~ l d groups. Useful ....Il;r.. I;r~ lu~al;llki..~
agents include but are not limited to those selected from the group consisting of acrylic or r ' jl;c esters of diois such as butanediol diacrylate, triols such as glycerol, and tetrols such as p..ltG.,.ylLIitol. Other useful crosslinking agents include but arc not limited to those selected from the group consisting of polyvinylic ~. u~I;..ki..~ agents, 15 such as substituted and ~nC~ ~hs~imted divinylbenzene; and .I;rl n~liû~ ' urethane acrylates, such as Ebecryl 270 and Ebecryl 230 (1500 weight average molecular wcight and 500û weight average molecular weight acrylated urethanes, respectively -both available from Radcure ~p~r;~ q) and mixtures thereof. Whcn used, crosslinker(s~ is (are) added at a level of up to about 0.1~ equivalent weight %, 20 preferably up to about 0.1 equivalent weight ~/0, of the total pulyl~ 8blc ~:~J~ J~ I;U~
(i.e. monomers plus optional u" - ' ' ~ , agenl). The "equivalent weight ~s'0" of a given compound is defined as the number of equivalents of that compound divided by thetotal number of equivalents in the total ru- l ~ , wherein an equivalent is the number of grams divided by the equivalent weight. The equivalent weight is defined as 25 the molecular weight divided by the number of poly...~ Glh~ groups in the monomer (in the case of thûse monomers with only one pol~.l,c. i~8blc group, equivalent weight =
molecular weight). The crosslinker can be added to any phase at any time before 100~~0 conversion. Preferably it is added before initiation occurs. Crosslinking can 21~17~2 r~
i~lJ occur via exposure to an a~ le radiation source, such as gamrna or electron beam radiation.
~1 u~yhc.~; Diameter S The r.li.,. u~ih . ~i, of the invention are normally tacky" l 2t~
organic ~ul~ but swellable in organic solvents, and small, typically having diameters of at least about I ~ _-u---.,t~.-, preferably in the range of about I to about 300 lllh~lu~ .t~ . When the Illi~,lua~h ~c~ are hollow, the voids typically range in size up to about 100 l..:_.u,,.~,t,,,~ or larger.
Following pol) .,.. " i,:.. liùn by any of these one-step or two-step processes, an aqueous suspensiûn ofthe hollow or solid lll;~lu~/h_.~,il is obtained which is stable to ag~' ~lliol) or roa~ under room l~ itu~ conditions (i.e., about 20 to about 25~C). The suspension may have a non-volatile solids contents offrom about lû to about 50 percent by weight. Upon prolonged standing, the 15 suspension separates into two phases, one phase being aqueous and sub~ lly free of polymer, the other phase being an aqueous suspension of l~ .l U~IJh_~ t:. Both phases may contain a minor portion of submicron latex particles. Decantation of the " ' c-rich phase provides an aqueous suspension having a non-volatile solids content on the order of about 40 to about 50 percent which, if shaken with water, will 2û readily redisperse. If desired, the aqueous suspension of "~ ,},~. c~ may be ulilized ~ ' '~ follo ving poly,~ aliùn to provide inherentiy tacky pressure-sensitive adhesive coatings. The suspension may be coated on suitable flexible or innexible backing materials by conventional coating techniques such as knife coating or Meyer bar coating or use of an extrusion die.
Once dried, the ll~ u~ , with sufficient agitation, will readily disperse in common organic liquids such as ethyl acetate, toluene, tcll~Lylllurul heptane, 2-butanone, benzene, CYCIVI.~,A...I~,, and esters. Solvent dispersions of the u~ may also be coated on suitable backing materials by .;u..~...liu....l coatingtechniques, as described above for aqueous ~
= ~
21~,~17~2 .. ~
WO Sf61012~1 P'f~TfrG'595.'08215 Suitable backin,g materiais for the aqueous or solvent based coatings include but are not limited to those selected from the group consisting of paper, plastic films, cellulose acetate, ethyl cellulose, woven or nonwoven fabric formed of synthetic or naturai materiais, metal, metallized polymeric fi!m, ceramic sheet material, and the 5 like. Prirners or binders may be used thereon.
S~ s or dispersions of the ~u;~,~u~uk~ in a liquid medium, e.g., water or an organic iiquid as described above, may be sprayed by ~,u.,.~ donal techniques without ~,ob.. bi,ing or may be il~ Ju~aled in aerosol containers with suitable propeilants including but not limited to those selected from the groups10 consisting of alkanes, alkenes, ~,LIulunuoluf~~ e.g.l Freon halocarbon propellents (f_UIIII~ f available from E.I. du Pont de Nemours & Co., Inc.~, and mixtures thereo~ Useful aerosol formulae have a solids content of ~rom about 5% to about 20%, preferably from about 10% to about 16%.
The pressure-sensitive adhesive properties of the u ",..~. ~;, may be 15 aitered by addition of tackifying resin and,'or plasticizer. It is also within the scope of this imention to include various other co .l .~ , such as pigments"~e.~L~ UliL;116 agents such as sodium hydroxide, etc., fillers, stabilizers, or various polyrneric additives. Preferabiy, the pressure-sensitive adhesive of the invention consistsessentially of the ua~ , of the invention, more preferably consists of the 20 ,.u~ , ' c, of the invention.
Test iMethods Tack The tack of sheets coated with the u.;~" " ' ~;, of the invention was measured with a Polyken Probe Tack tester (available from Kendall Company) 25 according to American Society fûr Testing and Materials Test Method ASTM
D2979-S8. I r , , ' ~ of the current invention were coated onto l 5 mil primed polyester film, yieiding a dried adhesive coating thickness of I to 2 mils. After cleaning the probe with ethyl acetate using a lint-free cloth, a 2 cm x 2 cnn sample of the adhesive coated sheet was piaced on the annular ring weight of the Polyken apparatus.
2191~2 ~0 9610128~ , "
The tack was then measured and recorded using a 10 mrr. stainiess steel probe having a diameter of 0.4975 cm with a speed of 0.5 cm/second and dwell time of I second.
cc Transition Temperature (T~e) S Glass transition t~ were measured using Differential Scanning C ' r at a heating rate of 20 C per minute ~bbreYintions ~ T- ' The following ablJ~ iùils and 1, ' are used herein.
AA acrylic acid Acrysol Acrysol A3, polyacrylic acid available from Rohm and Haas Co. which has been neutralized with NH40H
BDDA 1,4-butanediol diacrylate Biosofl Polystep BiosoftLAS-50,sodiumdodecyl benzene sulfonate available from Stepan Co.
DVB divinyl benzene HDDA 1,6 ! ' ' diacrylate IOA isooctyl acrylate ITA itaconicacid NA not available or not measured Siponate Siponate DS 10, sodium p-du ic~,~lb~
sulfonate available from Aicolac, Inc.
Span 80 Span 80TM, sorbitan , ~ m avaiiable from ICI Americas, Inc.
Standapol StandapolTMA, ammonium lauryl suifate available from Henkel AG
V2EH vinyl 2-clhylh.,Aanu.. le 2~3I7~
wo 96101~81 1 ~ ., ~.. .
VA vinyl acetate Vinol 350 VinolTM350, poiyvinyi alcohol available from Air Products Vi~l 205 VinolTM 205, polyYinyl aicohol available from Air Products VL vinyl laurate Examples The following Examples further illustrate but do not limit the invention.
10 Ail parts, pc~ t~ ., ratios, etc., in the Examples and the rest ofthe ~ sre by weight uniess indicated otherwise. M;~l ua~h~ ,o consisting of a ~"~d~ .e.
at least about 50 percent by weight) of al least one free radically pol~ ..,.,. ib diWe vinyl ester were prepared and examined for tack, diameter, Tg and n,u,, ' nl g~.
FY~m~ C I and 2 These examples illustrste the preparation of hollow taci~y l~ ua!Jh~lta by a onestep. ' ~ method.
Example I
In a one-liter resin reactor equipped with mechsnicai stirrer and inlet-outlet lines for Yacuum and argon, 450 grams of distilled and deionized water and 6.0 grams of StandapolTM A (Ammonium lauryl sulfate from Henkel AG) were charged and heated to 65~C. Next, 0.71 gram of LucidolTM-70 (70% bemoyl peroxide "~ available from Atochem North America, Inc.) wss dissolved in a mixture of 144 grams of Yinyl laurate, 6.0 grams of acrylic acid, and 0 04 gram of 1-4 butanediol diacrylate. When the LucidolTM-70 was dissolved, the rnonomer mixturewas added to the reactor while stirring at 400 RPM. Vacuum was applied to evacuate the reactor L' , ' c and the reactor was then purged with argon. The te~ . atu ~ 2191752 0 96101281 PCT/US95/082iS
of the reactor was maintained at 65~C for I S hours. An argon purge was maintained during the pol~ After the IS hour period, the suspension was allowed to cool to room i . ~;. The reactor was emptied and the suspension filtered.
~ Opticai ua~.u~ y showed hollow llfivlua,~/h~ .;, about 3û microns in diameter 5 containing multiple cavities of about 15% of the diameter of the ,..;~.. ~ , ' .,~.
Example 2 The same procedure described in Example I was followed with the exception that 144 grams of VynateTM 2EH ~vinyl 2-clLJ" available from 10 Union Carbide) were used instead of the vinyl laurate. The tCI~ alul c of the reactor was maintained at 65~C for 22 hours. At the end ofthe polynl. ~i~aliù~, optical IlliWU:~U~ showed hollow "~;~"ua~ ,.~ about 3û microns in diameter containing multiple cavities of about 15~~ of the diameter of the .,.;." u~.h~
Example 3 Thefollowingexampleillustratesthepreparationofhollowtack,v-,,;,,.ua~,L.,.~,i, using a two step: ' ~ method:
First, 0.75 gram of StandapolTM A was dissolved in 150 grams of distilled and deionized water and charged into a one-liter glass reactor equipped with a mechanical stirrer and iniet-outlet iines for vacuum and argon. A water-in-oil emulsion was20 prepared in an Omni mixer by stirring 75 grams of distilled and deionized water with 75 grams of vinyl laurate, 1.50 grams of Span 30TM (sorbitan .~ ol -l~ available from ICI Americas, Inc.) and 0.3G gram of LucidolTM-70. The water-in-oil emulsion was added to the reacto m ontaining the aqueous solution of StandapolTM A. The reactor was heated to 75~C while stirring at 400 RP~S. The reactor was kept at 75~C
25 for 22 hours and an argon purge was maintained during this time. After the 22 hour period, the suspension was allowed to cool to room tu~ .alulc. The reactor was emptiedandthesuspensionfiltered. Optical ~ us~,u~Jyshowedhollow ~ .,' ~ ~ 1 7 ~ ~
wo 96~0128~
ranging from 2 to 70 microns in diameter containing multiple cavities of at least 10~,~o of the diameter of the u~ ' c~.
Examples 4 and 5 The following examples illustrate the preparation of solid tacly ~ u ,t,h~
In E~xample 4 a polymeric stabilizer was used. In Example S a solid ".i. ,u..~ ,.c which did not I U~ polar monomer was made using a surfactant with an HLB less than 25.
Example 4 In a one-liter glass reactor equipped with a mechanical stirrer and inlet-outlet lines for vacuum and argon, 3 grams of VinolTM 3 50 (polyvinyl alcohol available from Air Products) were dissolved in 225 grams of distilled and deionized water. The reactor was heated to 75~C, its atmosphere evacuated by applying vacuum and refilling with argon. When the lel~ dlu~ ~ of the reactor reached 75~C~ a mixture 15 of 75 grams of VynateTM-2EH
and 0.36 grarns of LucidolTM7û were added. The agitation was set at 400 RPM. The reactor t~,,.t~.,,~tu~c was maintained at 75~C for 22 hours. An argon purge was maintained during the POIJ~ I;LdI;Vn After this time period the suspension was allowed to cod down to room t~",."..~lu.~. The reactor was emptied and the 2û suspension filtered. Optical r..;w.,s~v~y showed solid u~ u~ of about 90 microns in diameter.
Example 5 Solid u~ were prepared as in Example 4, ûnly that 2.17 grams 25 of Polystep BiosoR LAS-5û (sodium dodecyl benzene sulfonate available from Stepan Co., ~B ~y~ 'y 19) were used instead of polyvinyl alcohol. In addition~
0 ûl9 gram of divinylbenzene was used along with the Vynate-2EH. The 21~175~
0 96101281 1~
pui~ was carried out at 75~C for 30 hours. After pUlJ i~aLiOII~ optical J~_Uy~ showed solid ~.,ic,us~,h .~ of about 70 microns in diameter.
Examples 6 to lO
S The foiio ving examples, made in accordance with Example I and in the 1-- U~JUI Lu"~
stated in Table I, iilustrate the preparation of different tacky ,..;." u~i,l..,. us. In ali cases 225.0 grams of distilled and deionized water was used in the recipe. Ail pGI~ ' - were carried out at 75~C.
10 FY~ C 11 and 12 The following examples, made in accordance with Example 4 and in the IJ~u~ul~ions stated in Table I, illustrate the ,u~ Lùn of solid tacky lld~,~u~h~,.e~ using analternative polymeric stabilizer (Example 12) and a polar monomer and an alternative polymeric stablilizer (Example 11).
W0 9C/0 12~
c ,~ z _ ~tm t :i: N ~ ~ ~ ~ ~"
7 ¦ ~o ", ~ x ~I N _ 0 N --. ~ S S ~ ~ g S S S ,~ ~ ~, g . r r r ~ r 2 r r r ~
N O O r~ O O 11'1 0 0 0 0 0 U7 O _ o ..~r~ 0 ~ 1) r ~
-- ~ N ~ ~ ~ N ~ ut ~~
C Si ~ c ~,, , O
e~o ~~ c ~ _ -- O 10 . ~ e ~ ~
-. _ ,~, _ _ E _ ~~ r ~ 0 ~ 1' ~' ~ -- T
g > ~ r ~ ~
-24- o ~, 2~:917~2 0 96/01281 F~
While Ws invention has been described in connection with specific ' - " it should be, ' ~ that it is capable of further ~ f; ~ ;.,. . The claims herein ue intended to cover those vari2tions which one skilled in the artwould recognize as the chen~ical equivalent of what has been described here.
s -25- . ~_ J
8. The term "solvent sweliablcU in reference to a polymeric material 10 refers to a polymeric material that swells in solvent to an extent larger than its original dimension and forms a dispersion consisting, sllhct~nt~ y~ of individual particles.
All percents, parts, ratios, etc. described herein are by weight unless indicated otherwise.
15 Detailed Description of the Inv~ ntinn Free Radically rul~ h Ir Vinyl ~ster Monomers Useful ester monomers are oleophilic, water .,....,I~:r ~-lr, have restricted water solubility (less than about Iglper lOOg of water at 25~C), and as hu~uopul r 20 generally have glass transition t~ UIt:~ below about -] 0~C.
Vinyl ester monomers useful according to the invention are those of the general formula:
O
25 CH2=C{) C--CH2-R
iH
wherein Rl is selected from the group consisting of linear or branched 30 alicyl groups having I to 12 carbon atoms. Such vinyl esters include hut are not limited to those selected from the group consisting of vinyl 2-~LLJ:h~d~lodl~ vinyl caprate, s 219.1752 vinyl laurate, vinyi F ' ~uuat~" vinyl hexanoate, vinyl ,~"o~ ' - vinyl decanoate, vinyl octanoate, and other ~ ' u..~alul aLed vinyi esters of linear or branched carboxylic acids comprising 3 to 14 carbon atoms which as l~u~upu'r~
have glass transition tcl.liJ.,.alulc~ below about -10~C. Preferred vinyl ester monomers 5 include those selected from the group consisting of vinyl laurate, vinyl caprate, vinyl-2-cli..~" , and mixtures thereof.
Additionaily, u.~.' Ii~ ' - and phenyalkyl-substituted vinyl esters, such as those described in U.S. Patent No. 3,751,449 (Gobran et al.) having the formula set fonh i ' ' '~ below, can also be used in the ...i~. u~,h.,. .~O of the 10 present invention.
o R2 Il I .
CH2=CH (}C--CH--R3 where R2 is a ~iy~,loal;~vlldti~, or aromatic group (e.g., phenyl~, and R3 is a hydrogen atom or lower alkyl (e.g., with I to 6 carbon atoms).
Free Radically Pol~ iLaiJh, Polar Monomers The free radically pul~ .iL..iJl~, polar monomers useful in the present 20 invention are both somewhat oii-soluble and water-soiuble, resulting in a distribution of the polar monomer between the aqueous and the oil phases.
Representative examples of suitable polar monomers include but are not iimited to those seiected from the group consisting of acrylic acid, Ill~.~ha~,l yl;~. acidl itaconic acid, crotonic acid, maleic acid, fumaric acid, sulfoethyl ~..~,lI.a~,.yl..le, N-vinyi 25 ~ ,i; ione, N-vinyl Cal)lUla~.lalll~ 2-vinyl-4,4-dimethyl-2- ' ' e, t-butyl acrylamide, dimethyl amino ethyl acrylamide, N-octyl acryiamide, and ionic monomers such as sodium ~ lhaw~ylale~ ammonium acrylate, sodium acrylate, L~ L~...;..e p-vinyi benzimide, 4,4,9-l- i.,.elhji 1 azonia-7-oxo-8-oxa-dec-9-ene- 1 -sulphonate, N,N~ ' N (beta ...~ e~ yloxy-ethyl) ammonium propionate betaine, 30 1.i....lh,' ' - ll~ la~.l yL..kie~ I,I-dimethyl-1-(2,3-dihydroxypropyl)amine g 2 ~ S ~ ' WO 96101281 I ~
' ~" "e, mixtures thereof, and the like. Preferred polar monomers include thoseselectedfromthegroupconsistingof l ~OGI r ~ unoc,llu..~ acids, ~ r ~ di~ ui~yl;l, ncids, a.,- ~' ' , N-substituted a~ ' ' , salts thereof,and mixtures thereo~ Examples of such preferred polar monomers include but are not 5 limited to those selected from the group consisting of acrylic acid, sodium acrylate, N-vinyl ~ ul;dollc, and mixtures thereof.
Free Radically rcl~ .,..";GalJI~ Nonpolar Vinyl Monomers Free radically pùl~....,~'~blc nonpolar vinyl monomers which, as 10 hUII~"JU~ , have glass transition t~,lU~,. alw~,~ higher than about -10~C, e.g., tert-butyl acrylate, isoborn,vl acrylate, butyl methacrylate, vinyl acetate, ac,~l~ ilc, mixtures thereof, and the like, may optionally be utilized in ~u.~ iuu with ûne or moreofthevinylestermonomersprovidedthattheglasstransitiont~a~ Lulcofthe resultant copolyrner is below about -10~C.
Similarly, other free radically pOl~ ablc~ nonpolar vinyl monomers which, as humupulJu~ have glass transition Ltlll~ aLul~" lower than about -10~C,such as alkyl acrylate and lu.,Ll~.,lylah monomers, are useful in preparing the u.;~.. l , ' u.. and pressure-sensitive adhesives of this invention. Such alkyl acrylate and ' yht~ monomers are those ".. s'.. ~ l Ull~aLul~lled acrylate an 1 20 ~ h~ yldtt ester~ of non-tertiary alkyl alcohols, the alkyl groups of which preferably have from about 4 to about 14 carbon atoms. Examples of such monomers include but are not limited to those selected from the group consisting of isooctyl acrylate, 4-methyl-2-pentyl acrylate, 2-methylbutyl acrylate, isoamyl acrylate, sec-butyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, isodecyl l~ e~ isononyl acrylate,25 isodecyl acrylate, and mixtures thereof.
Preferred acrylate monomers include those selected from the group consisting of isooctyl acrylate, isononyl acrylate, isûamyl acrylate, isodecyl acrylate~
2-ethylhexyl acrylate, n-butyl acrylate, sec-butyl acrylate, and mixtures thereof 21917fii2 0 96/01281 PCT/USg!;~08215 ('~ R
The . , ' .,.. of this invention and the pressure-sensitive adhesives made therefrom comprise a copolymer comprising about 50 to about 100 percent by weight of at least one free radically p~ iJIe vinyl ester monomer; optionally, 5 about 0 to about 20 percent by weight of one or more polar monomers, (typically about 0.1 to about 20 percent, if included); and optionally about 0 to about 50 weight percent of a nonpolar free radicaily cu~,ul ~ ....,. ;~vl~ vinyl monomer (typically about 0.1 to about 50 percent by weight, if included), based upon the total weight of the copolymer.
Preferably, the pressure-sensitive adhesive Ul;~"U .~uI,c.~ comprise a 10 copolymer comprising about 60 to about 100 percent by weight offree radicallyPOI~ ;L~IIWC vinyl ester monomer; optionally, about 0 to about 15 percent by weight of at least one polar monomer (typically about 0.1 to about 15 percent, if included);
and optionally about 0 to about 30 weight of nonpolar free radically ~,o~Jvlrl~
vinyl monomer (typically about 0.1 to about 30 percent, if included) based upon the 15 total weight ofthe copolymer. Most preferably, the pressure-sensitive adhesive ~ u~h~o comprise a copolymer comprising about 70 to about 100 percent by weight of free radically pUirU~ iLl~iJI~ vinyl ester monomer; optionally about 0 to about 10 percent by weight of polar monomer (typically about û. I to about 10 percent by weight, if included), and optionally about 0 to about 20 percent (typically about 0.1 to 20 about 20 percent by weight, if included) by weight of nonpolar free radicallycu~,ul~ ' ' vinyl monomer, based upon the total weight of the copolymer.
Preferably, at least one polar monomer is included in the c ~ o~:l;u~
but l~lh~lV~ o may also be prepared using free radically pul.~."~.i~l,lc vinyl ester monomer(s) alone or without a polar monomer in ~.u .1. - ;o n only with other free 25 radically pul~ i~bic nonpolar vinyi monomers, such as isooctyl acrylate, vinyl acetate, etc. Most preferably, at least about I percent to about 10 percent by weight polar monomer is included as this ratio provides ...;.,,u~l,L.~ with balanced pressure-sensitive adhesive properties.
~1917$~2~ ~
~, W096fO1281 I~,1/~J.. ,_,~ ' ~
Two-Step ~Pth~l of Preparin~ Hollow Mi~
Aqueous a ~ of the hollow Illi~,luslJh.,.~O of the invention may be prepared by a "two-step" ' '~ process which first involves forming a water-in-oil emulsion of an aqueous solution of water and, if used, polar monomer(s), 5 in the oil phzse monomer ~i.e., at least vinyl ester monomer and optional nonpolar monomer), using an emulsifier having a low hydrophilic-lipophilic balancc ~HLB) value.
Where it is desirable not to include a polar monomer, an ar~ueous phase may be mixed directly with the oil phase monomer ~I.e., vinyl ester monomer and optional nonpolar monomer~, and emulsifier to form the water-in-oil emulsion.
Thehollow",w,' '~ ofthe ~ caOftheinventioncanbe determined through the choice of emulsifiers used in this "two-step~ process. Suitable emulsifiers for the use in the first step of the two step preparation of hollow ~.i.,l., ' ~O are those having HLB values below about 7, preferably in the range of about 2 to about 7. Examples of such emulsifiers include but are not limited to those 15 selected from the group consisting of sorbitan r~onnole~P~ sorbitan trioleate, ethoxylated oleyl alcohol ~such as Brij 93, available from Atlas Chemical Industries, Inc.), and mixtures thereof. It is noted that if a two-step method is followed in which the water-in-oil-in-water emulsion is unstable, solid m.~,u2,~ could result.
In the first step for preparing hollow ~I;W~ S~, oil phase 20 monomer~s), emulsifier, a free radical initiator, and optional wuOs r.l~ p monomer or monomers as defined below are combined, and an aqueous solution comprising waterand, if used, polar monomer~s) is agitated and poured into the oil phase mixture to form a water-in-oil emulsion. A thickening agent, such as methyl cellulose, may also be included in the aqueous phase of the water-in-oil emulsion. In the second step, a 25 water-in-oil-in-water emulsion is formed by dispersing the water-in-oil emulsion of the first step into an aqueDUs phase containing an emulsifier having an HLB vahle above about 6. Examples of such emulsifiers include but are not limited to those selected from the group consisting of ethoxylated sorbitan ~ ,ol~ , ethoxylated lauryl alcohol, alkyl sulfates1 and mixtures thereof. In both steps, when an emulsifier is ~w 21917~2 o 961012X1 r~
utilized, its . ~ ~ u ~ should be greater than its critical micelle ~u~ iull, which is herein defined as the minimum ru ~ of emulsifier necessary for theformation of micelles, i.e., sul,...;_, ua~,u~ &e,~ 1LiUIla of emulsifier molecules.
Critical miceUe; is slightly different for each emulsifier, usable 5 ~,.. ..S.~ ranging from about 1.0 x 10-4 to about 3.0 moles/liter. The final process step of the method of the invention involves ~he application of heat or radiation (such as ultraviolet radiation, etc.) to initiate PU~ ;L~I;OI~ of the monomers. One skilled in the art would be able to select an appropriate amount of heat and/or radiation depending on the initiator selected.
One-Step Method of Preparing Hollow M;_~ ua~Jh~
Aqueous s~ of hollow ~ u~L~.l ta which may contain polar monomer(s) may also be prepared by a ~one-step" ~ n process comprising aqueous suspension pol~ ."iL~liu.l of at least one vinyl ester monomer and optional 15 nonpolar monomer and, optionally, at least one polar monomer in the presence of at least one emulsifier capable of producing a water-in-oil emulsion inside the droplets which is ' "~ stable during e - ~ I ;r~n and pGI~ iLaLion. As in the two-step ~ ;. -,i. . process, the emutsifier is utilized in ~u..c~..L-~Lu,.. greater than its critical micelle ~ In general, emulsifiers formulated at this 20 c~.u - ~.,u..~ will produce stable cavity-containing droplets during the pUlJ. ;LllliUII, and are suitable for use in this one-step process. Examples of such emulsifiers include but are not limited to those selected from the group consisting Of.dk~;al~ . sulfates ~ such as sodium alkylarylether sulfate, e.g., Triton W/30, available from Rohm and Haas; " YI~I~IL~UIY~Ih~I sulfates such as alkylarylpoly~ethylene oxide) sulfates; alkyl 25 sulfates such as sodium lauryl sulfate, ammonium lauryl sulfate, 1,; I I -'~tA.1 ''~ lauryl sulfate, and sodium hexadecyl sulfate; alkyl ether sulfates such as ammonium lauryl ether sulfate, and alk~l~,olJ~LL, sulfates such as alkyl poly(ethylene oxide) sulfates;
~ ' yl.llyl~/ùl~Lh~. sulfonates such as alkylarylpoly(ethylene oxide~ sodium sulfonate (e.g., Triton X-200, co..,."~ lly available from the Rohm and Haas Co.j; alkyl - '2I9~752 WO 96/01281 I ~
benzene sulfonates such dS sodium p dod.c)'b~,.~..e sulfonate (e.g., Siponate DS -10, '1~ available from Alcolac, Inc.); alkyl ~ r~ t~ ~, such as Aerosol OT, a dioctyl ester of sodium SL~r ' ' acid ~,U-~ ,;ully available from American Cyanamid Process Chemicals Dept.; and mixtures thereof. Emulsifiers selected from 5 the group consisting of alkyl sulfates, all~yl ether sulfates, _L'.ylu. ~ I~,.h~ . sulfates, and mi~;tures thereof are preferred as they provide a maximum void volume per ".1.., . , ~; for a minimum amount of surfactant. Nonionic emulsifiers, e.g. Siponic Y-500-70 ~eLLu~' d oleyl alcohol, .,u--....~ ly available from Alcolac, Inc.) and Pluror;tc P103 (block copolymer of polypropylene oxide and pul~.,LLJI~ ,le oxide]O UIll,ll~ lly available form BASF Corporation), can also be utilized alonc or in with anionic emulsifiers, and mixtures thercof. Polymeric stabilizers may also be present but are not necessary.
One-SteD Method of Preparing Solid Miulua~Jl.c.l,~
Aqueous ~ J"~ of solid ~ u~Jh., ta may be prepared by a "one-step" ~ process comprising an aqueous suspension pulylll~ uLiull of at least one vinyl ester monomer; at least one polymeric stabiiizer, such as poly(vinyl alcohol~; optionally, at least one polar monomer, optionally, at least one nonpolar monomer, and/or optionally a ...uaal;lll~hlg monomer. It is believed that other polymeric stabilizers, such as those described in U.S. Patent No. 4,166,152 CBaker et al.~ ~e.g., carboxy-mûdified pûl~dC~ , carboxy-modified cellulûses, quaterndry arnine-substituted cellulûses~ etc.), and other steric or electrosteric polymeric stabilizers, including but not limited to those selected from the group consisting of pulyu~J.,.hyli.~c, polyacrylic acid, pul~ hq~ rylic acid, pol~u~"~;ulllide~ polyvillyl 25 ~ polyethylene imine, polyvinyl methyl ether, salts thereof, and mi~:turcs thereof, would also be useful according to the present invention.
It has also been found that aqueous suspension of solid ,..;~"u:,~)h.,.ti, not .l3u-~L;..~ any polar monomer may be prepared by a similar "one-step"
;. . process which h1GUl ,VUI dt~ a emulsifiers having HLB values lower than ~ , 0128~
about 25 rather than polymeric stabilizers in the formation of these ~";~"u~,h_.~,;,.
Examples of emulsifiers having HLB values lower than 25 include but are not limited to those selected from the group consisting of alh~l.,. ~ l,uu~ h~. sulfonates such as ! ~' ylal.~ (ethylene oxide) sodium sulfonate (e.g.,TritonTM X-200,, 5 available from the Rohm and Haas Co.); alkyl benzene sulfonates such as sodium p-dvd-,~,Jlb~ . sulfonate (e.~., PolystepTM Biosoft LAS-50, ~,u"....~ "), available from Alcolac, Inc.); alhyl ~ , such as AerosolTM OT, a dioctyl ester of sodium - ~r ' ' acid co.. ~,.. "~, available from American Cyanamid ProcessChemicals Dept.; and mixtures thereo~
All of these preparative methods may be modified by wilLl,old;.. g the addition of all or part, if used, of the polar monomer(s) and/or nonpolar monomer(s), if used~ and/or ~ ~ -r ' ~ wu~ hi~-g agent, if used, until after polylu~iLalion ofthe water-in-oil-in-water emulsion is initiated. This may be done provided that the withheld ~ o ~ are added to the pol~..,~,. i~i..~ mixture prior to its ] 00%15 conversion of monomers to polymer in the emulsion. This processing flexibility allows the formulator to add any portion of the optional polar monomer(s) and/or optional free radically pvl~ ' ' '- vinyl monomers and/or any portion of the mu~
.,., ~- ' ' ~ agent at any convenient point in preparing the pressure-sensitive adhesive of this invention.
Suitable initiators are those which are normally suitable for free radical pol~ ' of free radically pol.~ l,lc monomers and which are oil-soluble and of very low solubility in water (i.e., typically less than about 1 g per 100g of water at 25 20~C). Examples of such initiators include but are not limited to those selected from the group consisting of thermally-activated initiators such as azo c~ .,l.l,o ....1~, hydlu~.,. u~ id~, peroxides, and the like, and photoinitiators such as t ~ h benzoin ethyl ether, and 2,2-dimethoxy-2-phenyl ~ l .ol e, and the like, and mixtures thereof. Use of a water-soluble pul~ alioll initiator causes formation of 2~91~
wo sc/0l2sl P~rruss~ 2lq substantial amounts of latex. The initiator is generally used in an amount ranging fromabout 0.01 percent up to aboul 10 percent by weight of the total PUI~ GI~(i.e., monomers, and optional ~,lu~al;l~Lhlg agent), preferably up to about 5 percent.
s S~sslin,'cing Agents The CU"'I~'J' I;UI~ from which the ~ f." ' ~a ofthe invention are made mayalsocontaina r....~;r....~ , g agent. Theterm I~.r.. ~;.. =" as used herein refers to wus~ kill~, agents which possess two or more free radically 10 pu~ thJl~ u -~ l d groups. Useful ....Il;r.. I;r~ lu~al;llki..~
agents include but are not limited to those selected from the group consisting of acrylic or r ' jl;c esters of diois such as butanediol diacrylate, triols such as glycerol, and tetrols such as p..ltG.,.ylLIitol. Other useful crosslinking agents include but arc not limited to those selected from the group consisting of polyvinylic ~. u~I;..ki..~ agents, 15 such as substituted and ~nC~ ~hs~imted divinylbenzene; and .I;rl n~liû~ ' urethane acrylates, such as Ebecryl 270 and Ebecryl 230 (1500 weight average molecular wcight and 500û weight average molecular weight acrylated urethanes, respectively -both available from Radcure ~p~r;~ q) and mixtures thereof. Whcn used, crosslinker(s~ is (are) added at a level of up to about 0.1~ equivalent weight %, 20 preferably up to about 0.1 equivalent weight ~/0, of the total pulyl~ 8blc ~:~J~ J~ I;U~
(i.e. monomers plus optional u" - ' ' ~ , agenl). The "equivalent weight ~s'0" of a given compound is defined as the number of equivalents of that compound divided by thetotal number of equivalents in the total ru- l ~ , wherein an equivalent is the number of grams divided by the equivalent weight. The equivalent weight is defined as 25 the molecular weight divided by the number of poly...~ Glh~ groups in the monomer (in the case of thûse monomers with only one pol~.l,c. i~8blc group, equivalent weight =
molecular weight). The crosslinker can be added to any phase at any time before 100~~0 conversion. Preferably it is added before initiation occurs. Crosslinking can 21~17~2 r~
i~lJ occur via exposure to an a~ le radiation source, such as gamrna or electron beam radiation.
~1 u~yhc.~; Diameter S The r.li.,. u~ih . ~i, of the invention are normally tacky" l 2t~
organic ~ul~ but swellable in organic solvents, and small, typically having diameters of at least about I ~ _-u---.,t~.-, preferably in the range of about I to about 300 lllh~lu~ .t~ . When the Illi~,lua~h ~c~ are hollow, the voids typically range in size up to about 100 l..:_.u,,.~,t,,,~ or larger.
Following pol) .,.. " i,:.. liùn by any of these one-step or two-step processes, an aqueous suspensiûn ofthe hollow or solid lll;~lu~/h_.~,il is obtained which is stable to ag~' ~lliol) or roa~ under room l~ itu~ conditions (i.e., about 20 to about 25~C). The suspension may have a non-volatile solids contents offrom about lû to about 50 percent by weight. Upon prolonged standing, the 15 suspension separates into two phases, one phase being aqueous and sub~ lly free of polymer, the other phase being an aqueous suspension of l~ .l U~IJh_~ t:. Both phases may contain a minor portion of submicron latex particles. Decantation of the " ' c-rich phase provides an aqueous suspension having a non-volatile solids content on the order of about 40 to about 50 percent which, if shaken with water, will 2û readily redisperse. If desired, the aqueous suspension of "~ ,},~. c~ may be ulilized ~ ' '~ follo ving poly,~ aliùn to provide inherentiy tacky pressure-sensitive adhesive coatings. The suspension may be coated on suitable flexible or innexible backing materials by conventional coating techniques such as knife coating or Meyer bar coating or use of an extrusion die.
Once dried, the ll~ u~ , with sufficient agitation, will readily disperse in common organic liquids such as ethyl acetate, toluene, tcll~Lylllurul heptane, 2-butanone, benzene, CYCIVI.~,A...I~,, and esters. Solvent dispersions of the u~ may also be coated on suitable backing materials by .;u..~...liu....l coatingtechniques, as described above for aqueous ~
= ~
21~,~17~2 .. ~
WO Sf61012~1 P'f~TfrG'595.'08215 Suitable backin,g materiais for the aqueous or solvent based coatings include but are not limited to those selected from the group consisting of paper, plastic films, cellulose acetate, ethyl cellulose, woven or nonwoven fabric formed of synthetic or naturai materiais, metal, metallized polymeric fi!m, ceramic sheet material, and the 5 like. Prirners or binders may be used thereon.
S~ s or dispersions of the ~u;~,~u~uk~ in a liquid medium, e.g., water or an organic iiquid as described above, may be sprayed by ~,u.,.~ donal techniques without ~,ob.. bi,ing or may be il~ Ju~aled in aerosol containers with suitable propeilants including but not limited to those selected from the groups10 consisting of alkanes, alkenes, ~,LIulunuoluf~~ e.g.l Freon halocarbon propellents (f_UIIII~ f available from E.I. du Pont de Nemours & Co., Inc.~, and mixtures thereo~ Useful aerosol formulae have a solids content of ~rom about 5% to about 20%, preferably from about 10% to about 16%.
The pressure-sensitive adhesive properties of the u ",..~. ~;, may be 15 aitered by addition of tackifying resin and,'or plasticizer. It is also within the scope of this imention to include various other co .l .~ , such as pigments"~e.~L~ UliL;116 agents such as sodium hydroxide, etc., fillers, stabilizers, or various polyrneric additives. Preferabiy, the pressure-sensitive adhesive of the invention consistsessentially of the ua~ , of the invention, more preferably consists of the 20 ,.u~ , ' c, of the invention.
Test iMethods Tack The tack of sheets coated with the u.;~" " ' ~;, of the invention was measured with a Polyken Probe Tack tester (available from Kendall Company) 25 according to American Society fûr Testing and Materials Test Method ASTM
D2979-S8. I r , , ' ~ of the current invention were coated onto l 5 mil primed polyester film, yieiding a dried adhesive coating thickness of I to 2 mils. After cleaning the probe with ethyl acetate using a lint-free cloth, a 2 cm x 2 cnn sample of the adhesive coated sheet was piaced on the annular ring weight of the Polyken apparatus.
2191~2 ~0 9610128~ , "
The tack was then measured and recorded using a 10 mrr. stainiess steel probe having a diameter of 0.4975 cm with a speed of 0.5 cm/second and dwell time of I second.
cc Transition Temperature (T~e) S Glass transition t~ were measured using Differential Scanning C ' r at a heating rate of 20 C per minute ~bbreYintions ~ T- ' The following ablJ~ iùils and 1, ' are used herein.
AA acrylic acid Acrysol Acrysol A3, polyacrylic acid available from Rohm and Haas Co. which has been neutralized with NH40H
BDDA 1,4-butanediol diacrylate Biosofl Polystep BiosoftLAS-50,sodiumdodecyl benzene sulfonate available from Stepan Co.
DVB divinyl benzene HDDA 1,6 ! ' ' diacrylate IOA isooctyl acrylate ITA itaconicacid NA not available or not measured Siponate Siponate DS 10, sodium p-du ic~,~lb~
sulfonate available from Aicolac, Inc.
Span 80 Span 80TM, sorbitan , ~ m avaiiable from ICI Americas, Inc.
Standapol StandapolTMA, ammonium lauryl suifate available from Henkel AG
V2EH vinyl 2-clhylh.,Aanu.. le 2~3I7~
wo 96101~81 1 ~ ., ~.. .
VA vinyl acetate Vinol 350 VinolTM350, poiyvinyi alcohol available from Air Products Vi~l 205 VinolTM 205, polyYinyl aicohol available from Air Products VL vinyl laurate Examples The following Examples further illustrate but do not limit the invention.
10 Ail parts, pc~ t~ ., ratios, etc., in the Examples and the rest ofthe ~ sre by weight uniess indicated otherwise. M;~l ua~h~ ,o consisting of a ~"~d~ .e.
at least about 50 percent by weight) of al least one free radically pol~ ..,.,. ib diWe vinyl ester were prepared and examined for tack, diameter, Tg and n,u,, ' nl g~.
FY~m~ C I and 2 These examples illustrste the preparation of hollow taci~y l~ ua!Jh~lta by a onestep. ' ~ method.
Example I
In a one-liter resin reactor equipped with mechsnicai stirrer and inlet-outlet lines for Yacuum and argon, 450 grams of distilled and deionized water and 6.0 grams of StandapolTM A (Ammonium lauryl sulfate from Henkel AG) were charged and heated to 65~C. Next, 0.71 gram of LucidolTM-70 (70% bemoyl peroxide "~ available from Atochem North America, Inc.) wss dissolved in a mixture of 144 grams of Yinyl laurate, 6.0 grams of acrylic acid, and 0 04 gram of 1-4 butanediol diacrylate. When the LucidolTM-70 was dissolved, the rnonomer mixturewas added to the reactor while stirring at 400 RPM. Vacuum was applied to evacuate the reactor L' , ' c and the reactor was then purged with argon. The te~ . atu ~ 2191752 0 96101281 PCT/US95/082iS
of the reactor was maintained at 65~C for I S hours. An argon purge was maintained during the pol~ After the IS hour period, the suspension was allowed to cool to room i . ~;. The reactor was emptied and the suspension filtered.
~ Opticai ua~.u~ y showed hollow llfivlua,~/h~ .;, about 3û microns in diameter 5 containing multiple cavities of about 15% of the diameter of the ,..;~.. ~ , ' .,~.
Example 2 The same procedure described in Example I was followed with the exception that 144 grams of VynateTM 2EH ~vinyl 2-clLJ" available from 10 Union Carbide) were used instead of the vinyl laurate. The tCI~ alul c of the reactor was maintained at 65~C for 22 hours. At the end ofthe polynl. ~i~aliù~, optical IlliWU:~U~ showed hollow "~;~"ua~ ,.~ about 3û microns in diameter containing multiple cavities of about 15~~ of the diameter of the .,.;." u~.h~
Example 3 Thefollowingexampleillustratesthepreparationofhollowtack,v-,,;,,.ua~,L.,.~,i, using a two step: ' ~ method:
First, 0.75 gram of StandapolTM A was dissolved in 150 grams of distilled and deionized water and charged into a one-liter glass reactor equipped with a mechanical stirrer and iniet-outlet iines for vacuum and argon. A water-in-oil emulsion was20 prepared in an Omni mixer by stirring 75 grams of distilled and deionized water with 75 grams of vinyl laurate, 1.50 grams of Span 30TM (sorbitan .~ ol -l~ available from ICI Americas, Inc.) and 0.3G gram of LucidolTM-70. The water-in-oil emulsion was added to the reacto m ontaining the aqueous solution of StandapolTM A. The reactor was heated to 75~C while stirring at 400 RP~S. The reactor was kept at 75~C
25 for 22 hours and an argon purge was maintained during this time. After the 22 hour period, the suspension was allowed to cool to room tu~ .alulc. The reactor was emptiedandthesuspensionfiltered. Optical ~ us~,u~Jyshowedhollow ~ .,' ~ ~ 1 7 ~ ~
wo 96~0128~
ranging from 2 to 70 microns in diameter containing multiple cavities of at least 10~,~o of the diameter of the u~ ' c~.
Examples 4 and 5 The following examples illustrate the preparation of solid tacly ~ u ,t,h~
In E~xample 4 a polymeric stabilizer was used. In Example S a solid ".i. ,u..~ ,.c which did not I U~ polar monomer was made using a surfactant with an HLB less than 25.
Example 4 In a one-liter glass reactor equipped with a mechanical stirrer and inlet-outlet lines for vacuum and argon, 3 grams of VinolTM 3 50 (polyvinyl alcohol available from Air Products) were dissolved in 225 grams of distilled and deionized water. The reactor was heated to 75~C, its atmosphere evacuated by applying vacuum and refilling with argon. When the lel~ dlu~ ~ of the reactor reached 75~C~ a mixture 15 of 75 grams of VynateTM-2EH
and 0.36 grarns of LucidolTM7û were added. The agitation was set at 400 RPM. The reactor t~,,.t~.,,~tu~c was maintained at 75~C for 22 hours. An argon purge was maintained during the POIJ~ I;LdI;Vn After this time period the suspension was allowed to cod down to room t~",."..~lu.~. The reactor was emptied and the 2û suspension filtered. Optical r..;w.,s~v~y showed solid u~ u~ of about 90 microns in diameter.
Example 5 Solid u~ were prepared as in Example 4, ûnly that 2.17 grams 25 of Polystep BiosoR LAS-5û (sodium dodecyl benzene sulfonate available from Stepan Co., ~B ~y~ 'y 19) were used instead of polyvinyl alcohol. In addition~
0 ûl9 gram of divinylbenzene was used along with the Vynate-2EH. The 21~175~
0 96101281 1~
pui~ was carried out at 75~C for 30 hours. After pUlJ i~aLiOII~ optical J~_Uy~ showed solid ~.,ic,us~,h .~ of about 70 microns in diameter.
Examples 6 to lO
S The foiio ving examples, made in accordance with Example I and in the 1-- U~JUI Lu"~
stated in Table I, iilustrate the preparation of different tacky ,..;." u~i,l..,. us. In ali cases 225.0 grams of distilled and deionized water was used in the recipe. Ail pGI~ ' - were carried out at 75~C.
10 FY~ C 11 and 12 The following examples, made in accordance with Example 4 and in the IJ~u~ul~ions stated in Table I, illustrate the ,u~ Lùn of solid tacky lld~,~u~h~,.e~ using analternative polymeric stabilizer (Example 12) and a polar monomer and an alternative polymeric stablilizer (Example 11).
W0 9C/0 12~
c ,~ z _ ~tm t :i: N ~ ~ ~ ~ ~"
7 ¦ ~o ", ~ x ~I N _ 0 N --. ~ S S ~ ~ g S S S ,~ ~ ~, g . r r r ~ r 2 r r r ~
N O O r~ O O 11'1 0 0 0 0 0 U7 O _ o ..~r~ 0 ~ 1) r ~
-- ~ N ~ ~ ~ N ~ ut ~~
C Si ~ c ~,, , O
e~o ~~ c ~ _ -- O 10 . ~ e ~ ~
-. _ ,~, _ _ E _ ~~ r ~ 0 ~ 1' ~' ~ -- T
g > ~ r ~ ~
-24- o ~, 2~:917~2 0 96/01281 F~
While Ws invention has been described in connection with specific ' - " it should be, ' ~ that it is capable of further ~ f; ~ ;.,. . The claims herein ue intended to cover those vari2tions which one skilled in the artwould recognize as the chen~ical equivalent of what has been described here.
s -25- . ~_ J
Claims (10)
1. A tacky, polymeric, organic solvent-insoluble, elastomeric pressure sensitive adhesive microsphere comprising:
a (co)polymer having a Tg of less than about -10°C comprising the (co)polymerization product of:
(a) about 50 to about 100 percent by weight of at least one free radically polymerizable vinyl ester monomer wherein a polymer prepared from the monomer would have a Tg of less than about - 10°C;
(b) about 0 to about 20 percent by weight of at least one polar monomer copolymerizable with the monomer of element (a) and element (c), if included;
(c) about 0 to about 50 percent by weight of nonpolar free radically polymerizable vinyl monomer, the nonpolar monomer being copolymerizable with the monomer of element (a) and element (b), if included, wherein the weight percentages of (a), (b), and (c) are based upon the total weight of the (co)polymer; and (d) about 0 to about 0.15 equivalent weight percent of a multifunctional crosslinking agent based upon the total weight of the monomers plus the crosslinking agent.
a (co)polymer having a Tg of less than about -10°C comprising the (co)polymerization product of:
(a) about 50 to about 100 percent by weight of at least one free radically polymerizable vinyl ester monomer wherein a polymer prepared from the monomer would have a Tg of less than about - 10°C;
(b) about 0 to about 20 percent by weight of at least one polar monomer copolymerizable with the monomer of element (a) and element (c), if included;
(c) about 0 to about 50 percent by weight of nonpolar free radically polymerizable vinyl monomer, the nonpolar monomer being copolymerizable with the monomer of element (a) and element (b), if included, wherein the weight percentages of (a), (b), and (c) are based upon the total weight of the (co)polymer; and (d) about 0 to about 0.15 equivalent weight percent of a multifunctional crosslinking agent based upon the total weight of the monomers plus the crosslinking agent.
2. The microsphere of claim 1 wherein the vinyl ester monomer is selected from the group consisting of vinyl 2-ethylhexanoate, vinyl caprate, vinyl laurate, vinyl pelargonate, vinyl hexanoate, vinyl propionate, vinyl decanoate, vinyl octanoate, and mixtures thereof.
3. The microsphere of claim 1 which is hollow.
4. The microsphere of claim 1 which is solid.
5. A coated substrate comprising a backing at least partially coated with the microspheres of claim 1.
6. A suspension comprising the microspheres of claim 1 in a liquid medium.
7. A dispersion comprising the microspheres of claim 1 in a liquid medium.
8. A repositionable spray pressure-sensitive adhesive comprising the microspheres of claim 1 and a propellant.
9. A tacky, polymeric, organic solvent-insoluble, elastomeric pressure sensitive adhesive microsphere comprising:
a (co)polymer having a Tg of less than about -10°C comprising the (co)polymerization product of:
(a) about 60 to about 100 percent by weight of at least one free radically polymerizable vinyl ester monomer wherein a polymer prepared from the monomer would have a Tg of less than about -10°C;
(b) about 0.1 to about 15 percent by weight of at least one polar monomer copolymerizable with the monomer of element (a) and element (b), if included;
(c) about 0.1 to about 30 percent by weight of nonpolar free radically (co)polymerizable vinyl monomer, the nonpolar monomer being copolymerizable with the monomer of element (a) and element (b), if included, wherein the weight percentages of (a), (b), and (c) are based upon the total weight of the (co)polymer; and (d) about 0 to about 0.15 equivalent weight percent of a multifunctional crosslinking agent based upon the total weight of the monomers plus the crosslinking agent.
a (co)polymer having a Tg of less than about -10°C comprising the (co)polymerization product of:
(a) about 60 to about 100 percent by weight of at least one free radically polymerizable vinyl ester monomer wherein a polymer prepared from the monomer would have a Tg of less than about -10°C;
(b) about 0.1 to about 15 percent by weight of at least one polar monomer copolymerizable with the monomer of element (a) and element (b), if included;
(c) about 0.1 to about 30 percent by weight of nonpolar free radically (co)polymerizable vinyl monomer, the nonpolar monomer being copolymerizable with the monomer of element (a) and element (b), if included, wherein the weight percentages of (a), (b), and (c) are based upon the total weight of the (co)polymer; and (d) about 0 to about 0.15 equivalent weight percent of a multifunctional crosslinking agent based upon the total weight of the monomers plus the crosslinking agent.
10. A method of making solid microspheres comprising the steps of:
(a) forming droplets by mixing together:
(i) at least one free radically polymerizable vinyl ester monomer, wherein a polymer prepared from the monomer would have a Tg of less than about -10°C;
(ii) optionally at least one free radically polymerizable nonpolar monomer;
(iii) at least one emulsifier having a hydrophilic-lipophilic balance value of less than about 25;
(iv) an aqueous medium; and (v) optionally at least one multifunctional crosslinking agent;
(b) initiating polymerization; and (c) adding all or any remaining portion of nonpolar monomer(s), if used, and all or any remaining portion of multifunctional crosslinking agent, if used, prior to the 100% conversion of the monomer contained in the droplets.
(a) forming droplets by mixing together:
(i) at least one free radically polymerizable vinyl ester monomer, wherein a polymer prepared from the monomer would have a Tg of less than about -10°C;
(ii) optionally at least one free radically polymerizable nonpolar monomer;
(iii) at least one emulsifier having a hydrophilic-lipophilic balance value of less than about 25;
(iv) an aqueous medium; and (v) optionally at least one multifunctional crosslinking agent;
(b) initiating polymerization; and (c) adding all or any remaining portion of nonpolar monomer(s), if used, and all or any remaining portion of multifunctional crosslinking agent, if used, prior to the 100% conversion of the monomer contained in the droplets.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US27002194A | 1994-07-01 | 1994-07-01 | |
| US08/270,021 | 1994-07-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2191752A1 true CA2191752A1 (en) | 1996-01-18 |
Family
ID=23029564
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002191752A Abandoned CA2191752A1 (en) | 1994-07-01 | 1995-06-30 | Tacky microspheres prepared from vinyl ester monomers |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0769029A1 (en) |
| JP (1) | JPH10502410A (en) |
| CA (1) | CA2191752A1 (en) |
| WO (2) | WO1996001280A1 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0888412B1 (en) * | 1996-03-21 | 2002-09-11 | Minnesota Mining And Manufacturing Company | Pressure sensitive adhesive film comprising tacky microspheres |
| US5889118A (en) * | 1996-06-03 | 1999-03-30 | Minnesota Mining And Manufacturing Company | Thermomorphic "smart" pressure sensitive adhesives |
| US5824748A (en) * | 1996-06-03 | 1998-10-20 | Minnesota Mining And Manufacturing Company | Composite pressure sensitive adhesive microspheres |
| US5888650A (en) * | 1996-06-03 | 1999-03-30 | Minnesota Mining And Manufacturing Company | Temperature-responsive adhesive article |
| US6312715B1 (en) | 1998-05-01 | 2001-11-06 | 3M Innovative Properties Company | Adhesive microsphere drug delivery composition |
| US7354596B1 (en) | 1998-05-01 | 2008-04-08 | 3M Innovative Properties Company | Anti-microbial agent delivery system |
| US6471975B1 (en) * | 1998-05-01 | 2002-10-29 | 3M Innovative Properties Company | Microspheres as a delivery vehicle for bio-active agents useful in agricultural applications |
| US6883908B2 (en) | 2001-01-08 | 2005-04-26 | 3M Innovative Properties Company | Methods and compositions for ink jet printing of pressure sensitive adhesive patterns or films on a wide range of substrates |
| CN113801267A (en) * | 2021-09-24 | 2021-12-17 | 长春工业大学 | Thermosensitive polymer nano-microsphere for profile control and flooding and preparation method thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1350937A (en) * | 1962-01-25 | 1964-01-31 | Shell Int Research | Process for preparing latex by emulsion polymerization of vinyl esters |
| FR1524534A (en) * | 1966-05-20 | 1968-05-10 | Basf Ag | Process for the preparation of aqueous dispersions of vinyl propionate polymers |
| US5196495A (en) * | 1991-01-25 | 1993-03-23 | Isp Investments Inc. | Hair fixative polymers |
| TW338043B (en) * | 1992-12-11 | 1998-08-11 | Minnesota Mining & Mfg | Tacky microspheres having pendant hydrophilic polymeric or oligomeric moieties |
-
1995
- 1995-06-29 WO PCT/US1995/008139 patent/WO1996001280A1/en active Application Filing
- 1995-06-30 JP JP8503923A patent/JPH10502410A/en active Pending
- 1995-06-30 WO PCT/US1995/008215 patent/WO1996001281A1/en not_active Application Discontinuation
- 1995-06-30 CA CA002191752A patent/CA2191752A1/en not_active Abandoned
- 1995-06-30 EP EP95925382A patent/EP0769029A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| WO1996001280A1 (en) | 1996-01-18 |
| JPH10502410A (en) | 1998-03-03 |
| EP0769029A1 (en) | 1997-04-23 |
| WO1996001281A1 (en) | 1996-01-18 |
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