CA2171483A1 - Foamed acrylic desiccant - Google Patents
Foamed acrylic desiccantInfo
- Publication number
- CA2171483A1 CA2171483A1 CA002171483A CA2171483A CA2171483A1 CA 2171483 A1 CA2171483 A1 CA 2171483A1 CA 002171483 A CA002171483 A CA 002171483A CA 2171483 A CA2171483 A CA 2171483A CA 2171483 A1 CA2171483 A1 CA 2171483A1
- Authority
- CA
- Canada
- Prior art keywords
- polymer
- desiccating
- acrylic
- pressure
- means according
- 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
- 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
- C09J133/062—Copolymers with monomers not covered by C09J133/06
- C09J133/064—Copolymers with monomers not covered by C09J133/06 containing anhydride, COOH or COOM groups, with M being metal or onium-cation
-
- 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
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/10—Esters
- C08F220/12—Esters of monohydric alcohols or phenols
- C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
- C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
- C08F220/1802—C2-(meth)acrylate, e.g. ethyl (meth)acrylate
-
- 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
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/10—Esters
- C08F220/12—Esters of monohydric alcohols or phenols
- C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
- C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
- C08F220/1804—C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate
-
- 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
- C08F222/00—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 a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides, or nitriles thereof
- C08F222/04—Anhydrides, e.g. cyclic anhydrides
- C08F222/06—Maleic anhydride
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
An essentially solvent-free acrylic polymer is produced from acrylic monomers while removing the reaction solvent during the polymerization process. The polymer is foamed and crosslinked to provide a pressure-sensitive cellular material of a wide range of tack and adhesion, depending on the extent of the crosslinking reaction of that polymer. The foaming is achieved by a spontaneous release of gaseous substance from the desiccating agent in the formulation during the crosslinking process. The foamed product is used for desiccating sealed systems.
Description
Field of the Invention The present invention relates to the polymerization of acrylic m~ nomer~ to a liquid polymer and the formation of a cellular crosslinked material by the release of a gaseous m~teri~l during the cr~linking process of the polymer, providing a p~ e-s~ ve adhesive m~t~ri~l suitable as a desiccant for sealed systems such as in~ tç-l windows.
: ~ :: :
.
Background of the Invention.
The polymrri7~tion of acrylic monomrrs is generally carried out in organic solvents or in aqueous emulsions. If a solventless polymer is required, the solvents are removed after the co~ letion of the polymeri7~tion. When a solvent-col~tail.il.g polymer is applied, S the solvent is released from the polymer or from its formul~tlod product.
Such pr~rtir~Ts have several di~d~rall~ges: Firstly, acrylic polymeri_ations arestrongly exothrrmic and require large amounts of a cooling mPrlillm. Secondly, the e~,al)oltllion of the solvent from the polymeric m~trri~l after its appli~tion and during its use causes col.ls.l..il.~lion of the envl~ol.l..rnt. Thirdly, such a solvent loss lepIesenl~ an 10 unrecoverable loss of a material. It is therefore desirable to develop a polymeri7~tion L~loc~es in which at least part of the heat of the polymrri7~tion is removed by an tive cooling process, and during which a ~i_nifir~nt part of the solvent is removed.
It is also desirable to reduce the total amount of the material in a final product and at the same time to increase the effectiveness of the function of that material in the final 15 product. Several approaches are known in the art for redl~ring the amount and ~lo~lLion of a polymeric ccs ~ ;nl in a product formul~tinn. One approach is to provide foamed products. But the process of introdllrinp a gaseous conl~ollent into a crc~link~ble polymeric formlll~tion~ several problems. The ch~l..ic~l cro~linking reactions and the rate of foaming must be suitably ~l~nred to achieve the proper cellular structure under 20 production and ~ce~il._ conditions~ This is particularly difficult when the product is to be ~efol.~ed by extrusion, l~min~tion or ~hr~tin_, and when it c.,l..p.i~es additional particulate additives, such as desiccant materials.
Objects of the Invention It is accordingly an object of the present invention to overcome the deficiencies of the 25 prior art such as in-lir~ted above~
It is an object of this invention to provide a process for the production of an nti~lly solvent-free acrylic polymer by the polymPri7~tion of the monom.or~ under 217~83 conditions whereby the heat of the reaction is used to distill of the solvent while the nlul~lllers are being added during the polymPri7~tion reaction.
It is another object of this invention to provide a process for the simllh~neousçhemir~lly c~ .king and foaming of an acrylic polymer in which cl~ kinp and S foaming proceed below 100 degrees C and preferably at ambient tell~ra~ s.
It is another object of this invention to provide a process for a cellular pl~
sel~ilive ~lesicc~ting means by the action of a particulate desicc~ting material as the source of the foaming agent in said desicc~ting means.
It is another object of the present invention to provide a ~ ule-scnsitive d~cc~tin_ 10 means cc~ plisillg a formlll~tion based on an acrylic polymer, whereby the tack and adhesion is modified by the degree of the chemical cro~linking of that acrylic c~lll~llelll.
It is another object of this invention to provide a pIe~ulc-scnsitive desiccating means whereby the product C.,l..p1 i~es a cellular com~iilion.
It is a further object of this invention to provide a ple~ul~-sc~ ive celluIar 15 dP-ei~-~tinp means col..p. i!~illp a gr~nul~r desiccant, whereby the si_e of the granules sets a limit to the c.,l"pr~ibility of said desicc~ting means.
It is another object of this invention to provide a ~le ~iul~-SCl~ilive cellulard~ rc~ting means suitable for sealed insulated window systems.
S-lmm~ry of the Invention The novel products of the present invention are especi~lly useful as desiccatingmaterials in the m~nuf~ctllrin_ of sealed window systems. The materials can be extruded and shaped into tapes or string-like shapes, or sheets, suitable for slitting into various ;on~, and are of varying degrees of tackiness and arlh~ion. The essential ingredients are a pI~u~-sensitive polymer, a desicc~ting agent, which is also the foaming agent, and a ~ lil.king agent. The cro~clinking agent is chosen to assure that the cr~elinkin_ of the m~t~ri~l ~Ioceeds at a such a rate that the formulation can be ~.oce~ed, but that the foaming occurs çe~nti~lly after that ~ .il.g, in the already at least partially crr~elink~.l ~ form~ tion.
In a preferred embodiment of the invention, a process is applied for the polym~ri7~tion of acrylic monomers in a solvent whereby the solvent is at least partially removed by the heat of the polymeti7~tion reaction, providing an e~nti~lly solvent-free 5 polymer after the polymeri_ation reaction is e~nti~lly completed. This requires the use of solvents of lower boiling point than that of the acrylic monomlo~.
The acrylic polymes suitable for my inventions have average molecular weights inthe range of 50,000 to 1,000,000 but preferably in the range of 200,000 and 600,000. The Lqefe~l~ acrylic polymers used in this invention are of a cul-lL~ilion that is inherently 10 tacky and suitable for p~ sensitive c~llp~il inn~. The tackiness is achieved by using alkyl acrylates such as butyl acrylate or its higher homologues as co-nlollul~lers in the polyll~f l i~ .lion, as known in the art. The polymer further is provided with functional groups that make the polymer suitable for cro~linking to provide an elastic m~t.ori~l Such suitable functional groups are introduced through co-monomer~, or by function~ql;7ing the polymers 15 through the grafting of such functional groups. A plefell~l reactive group is the anhydride filn~tion~lity. If maleic anhydride is used as a co-monoml-r in the polymerization, a concentration of maleic anhydride in the monom.or n~ e is in the range of .1 to 20% by weight is generally acceptable, but between 0.5 and 5% is pl~f~,~d for a ~ sel~iLive product. High ~IopolLions of maleic anhydride cause ..~ ble hardness in the final 20 product.
The cro~linking agent for the polymer is a m~tPri~l that reacts with the anhydride functic.n~lity on that acrylic polymer. The cr~linking is achieved with a m~t~ri~l cont~ining one or more of the groups C-NH2 or C-NHRl, whereby Rl is an alkyl group or a substitlltYl alkyl group, and wherein said alkyl group may have a furdler functionality 25 attached to itself, such as an ester functional-ity. The rate of cro~linking is ~l~.t. ,..il.~d by the type and degree of substitlltion on the nitrogen atom in that silane; the rate is highest when both substitu~nt~ are l~og~;ll. In my invention, cr~linking at a suitable rate to allow the ploce~ g of the formul~tion is achieved by the addition to that anhydride-217148~
modified polymer of a mAteriAl which co~ s such p~ or secondary amino groupand also a silane group of the general formula -Si-(OR)n, wherein n = 3, and wherein the -RgroupsatelyL -~lly methoxy-OCH3, orethoxy-CH2CH3.
A desirable mAtrriAl of that structure is the ~A.1-lition product of an alkylacrylate such S as ethylacrylate and gamma-amino~I~yll~ oxysiloxane, which consists partially of the isomer HN -CH2CH2CH2 Si ( OCH2CH3)3 o The mAtPriAl is suitable for the production of a cellular pl~bu,e-scnsitive product.
A cro~clinl~-l tacky cellular acrylic mAt~riAl is o~tail,cd by adding a ct~linking agent and by providing a source of a gaseous col~ ,ent.
The unexpected and useful finding is that the use of grAnlllAr mAtrriAl~, such ~ silica in comhinAtion with the acrylic polymer and an amino-functional silane reagent, provides a 15 process for the ptoduction of a cr~link~1 cellular ~ e-sc~ ive desicc~ting product.
The cellular c~m~iilion is preferably achieved by the addition of molecular sieve adso~ ,l, specifically the Molecular Sieves supplied ftom the Union Carbide/UOP
C~ . A further ~ ing and novel finding is that cr~linking and foaming is achieved at prActir~l and suitable rates at ambient tel"p~.~ture, although both can be 20 accelerated at elevated tel~ lu,~ The formlllAt~d mAt~.tiAl based on such a plocebb can be extruded before ~ignifi(~nt cr~linking and foa~ g has occurred.
The suitable Molecular Sieve can be of a wide range of pore structutes, but is preferably of a nomin~l pore ~ m~ter be~ 3 to 10 Angb11~lls, ~ provided by the Molecular Sieves 3A, 4A or 13X. The moisture content of the particulate mAtrriAl is in the 25 range of 0.1 to 15%, and preferably in the range of 0.1 o 5%; it should not exceed l5~Zo if the f~rmlllAtion is to be used as a desicc-Ating mAtrriAl. The amount of Molecular Sieve in the f~rmlllAtion is in the range of 1 to 200 parts per 100 parts of the polymer but is preferentially between S and 50 parts. The Molecular Sieve thus provides the final formlllAtion with an adsorption function such as the removal of water from its ~llvihul)~ t, but also provides a process for the formation of a crQsxlinl~l cellular structure.
The acrylic polymer may contain some moixt.lre, but the upper limit of the moix~lre content of the acrylic polymer should not exceed 2 %. Where required, the fc.rmlllAtion may S also c s~ i ~ al)~rop~ e additional resins to modify the tackiness of the product, may .I..p1 i.~ adhesion promoters, as well as antidegrA.lAnt~ to increase the long-term stability of the product.
Finely divided inorganic filler(s) e.g. calcium carbonate, zinc oxide, barytes, talc or others ( and niL~lules) may be included to improve the ploce~ixil-g and h~n-lling plo~llies of the product. SllbstAntiAl amounts of filler may be used, i.e. up to 100 parts per weight of the polymer formlllAtion, but plcf. ll~ amounts between S and 20 parts, since at higher levels the flexibility of the product is reduced. If desired, finely divided carbon black or other pi~mentx may be included to provide the desirable colour or tint. Recall~e of the stability of acrylic polymers to heat and oxidative degradation, the products of my invention are suitable as an ell./hol .1. ~PntAlly ~i~t~lt sealant and as mAteriAlx for the desiccation of closed systems such as sealed inx~llAtP~ window systems.
F.~mrle I
tion of the Acrylic Polymer of Low Solvent Level. A polymeri7Ation reactor typical for the production of liquid acrylic polymers in solvent is used. To the reactor is added 400 g of ethyl acetate solvent which is heated to reflux. The reactor is equipped with two reservoirs. The first reservoir colllaills 3880 g of the monomPr butyl acrylate in which is dissolved 60 g of maleic anhydride, and 5.2 g of lauryl nlelca~ as a chain lldl~rtl agent. The second reservoir CUlll~linS a solution of the initiAtors for the thPrmAl polymPri7Ation, 48 g of lauryl peroxide and 12 g of ethyl-3,3~i(t-~ll~ y) butyrate, in 480 g of ethyl acetate. Two streams of the reagents from both reservoirs are added in a controlled way to ensure the l~nl~e~ ul~; mAintAinC a steady removal of the ethyl acetate solvent ~ the cooling in the contlPnxPr is discol.~ P~1 The monomer~ are added 8 2171~8~
over a period of 110 minllt~Pe and the initi~tor over 120 minlltP~ Some heating of the reaction ve~el may be required to increase the rate of solvent removal during the poly~ l ;on When the polymPri7~ti~ n ttn,~r&~ has reached 140 C, further heating is required until the range of 170-180 C is reached, at which the solvent is e~ llyS cc~ pl_tely removed from the polymer. The ethylacetate content is then le~ than 1%.
F,~mple II
Preparation of the crosslinking agent for the acrylic polymer. Equimolar amountsof ethyl acrylate and gamma-amino~ ;cthoxysilane are combinP~ and mixed for 10 a~ Aillldtely S l~ c under the exclusion of nl~ . The reaction is exoth.-rmic. The tcl~ dtul~ of the solution is l..~ .P~1 during the mixing and for another hour at below 60 centigr~d~P. The product is stored in a closed cont~inpr to reduce the eA~iulc to iX~
1S F.~mple m Preparation of a Pressure~ensitive Desiccating Product: To lOOg of a copolymer of butyl acrylate and maleic anhydride of the ~lopulLion of 98.5:1.5 and of an average molecular weight of 300,000 is added 100 g of molecular sieve ad~c lI,ent and lg of the equimolar addition product of ethyl acrylate and gamma-all~i~ p~ lllicthoxysilane as 20 described in Example II. The m~tPri~l is mixed at ambient tenlpeld~ until the powder is di~cd, and is then extruded in the desirable shape onto a s~lbstr~te such as a release paper from which it can be removed when later applied. The m~tPri~l develops its cellular structure on storage in a sealed container, and is an elastic and plG~u~ scnsitive adhesive.
F.~mple IV
Preparation of a Non-tacky De~2~ -~ing Product: The process is desc~ibed as in Example m, except that 2 grams of the ad-liti- n product of ethylacrylate and gamma-amin~ icthoxysilane, described in Example lL is added to the n~L~
: ~ :: :
.
Background of the Invention.
The polymrri7~tion of acrylic monomrrs is generally carried out in organic solvents or in aqueous emulsions. If a solventless polymer is required, the solvents are removed after the co~ letion of the polymeri7~tion. When a solvent-col~tail.il.g polymer is applied, S the solvent is released from the polymer or from its formul~tlod product.
Such pr~rtir~Ts have several di~d~rall~ges: Firstly, acrylic polymeri_ations arestrongly exothrrmic and require large amounts of a cooling mPrlillm. Secondly, the e~,al)oltllion of the solvent from the polymeric m~trri~l after its appli~tion and during its use causes col.ls.l..il.~lion of the envl~ol.l..rnt. Thirdly, such a solvent loss lepIesenl~ an 10 unrecoverable loss of a material. It is therefore desirable to develop a polymeri7~tion L~loc~es in which at least part of the heat of the polymrri7~tion is removed by an tive cooling process, and during which a ~i_nifir~nt part of the solvent is removed.
It is also desirable to reduce the total amount of the material in a final product and at the same time to increase the effectiveness of the function of that material in the final 15 product. Several approaches are known in the art for redl~ring the amount and ~lo~lLion of a polymeric ccs ~ ;nl in a product formul~tinn. One approach is to provide foamed products. But the process of introdllrinp a gaseous conl~ollent into a crc~link~ble polymeric formlll~tion~ several problems. The ch~l..ic~l cro~linking reactions and the rate of foaming must be suitably ~l~nred to achieve the proper cellular structure under 20 production and ~ce~il._ conditions~ This is particularly difficult when the product is to be ~efol.~ed by extrusion, l~min~tion or ~hr~tin_, and when it c.,l..p.i~es additional particulate additives, such as desiccant materials.
Objects of the Invention It is accordingly an object of the present invention to overcome the deficiencies of the 25 prior art such as in-lir~ted above~
It is an object of this invention to provide a process for the production of an nti~lly solvent-free acrylic polymer by the polymPri7~tion of the monom.or~ under 217~83 conditions whereby the heat of the reaction is used to distill of the solvent while the nlul~lllers are being added during the polymPri7~tion reaction.
It is another object of this invention to provide a process for the simllh~neousçhemir~lly c~ .king and foaming of an acrylic polymer in which cl~ kinp and S foaming proceed below 100 degrees C and preferably at ambient tell~ra~ s.
It is another object of this invention to provide a process for a cellular pl~
sel~ilive ~lesicc~ting means by the action of a particulate desicc~ting material as the source of the foaming agent in said desicc~ting means.
It is another object of the present invention to provide a ~ ule-scnsitive d~cc~tin_ 10 means cc~ plisillg a formlll~tion based on an acrylic polymer, whereby the tack and adhesion is modified by the degree of the chemical cro~linking of that acrylic c~lll~llelll.
It is another object of this invention to provide a pIe~ulc-scnsitive desiccating means whereby the product C.,l..p1 i~es a cellular com~iilion.
It is a further object of this invention to provide a ple~ul~-sc~ ive celluIar 15 dP-ei~-~tinp means col..p. i!~illp a gr~nul~r desiccant, whereby the si_e of the granules sets a limit to the c.,l"pr~ibility of said desicc~ting means.
It is another object of this invention to provide a ~le ~iul~-SCl~ilive cellulard~ rc~ting means suitable for sealed insulated window systems.
S-lmm~ry of the Invention The novel products of the present invention are especi~lly useful as desiccatingmaterials in the m~nuf~ctllrin_ of sealed window systems. The materials can be extruded and shaped into tapes or string-like shapes, or sheets, suitable for slitting into various ;on~, and are of varying degrees of tackiness and arlh~ion. The essential ingredients are a pI~u~-sensitive polymer, a desicc~ting agent, which is also the foaming agent, and a ~ lil.king agent. The cro~clinking agent is chosen to assure that the cr~elinkin_ of the m~t~ri~l ~Ioceeds at a such a rate that the formulation can be ~.oce~ed, but that the foaming occurs çe~nti~lly after that ~ .il.g, in the already at least partially crr~elink~.l ~ form~ tion.
In a preferred embodiment of the invention, a process is applied for the polym~ri7~tion of acrylic monomers in a solvent whereby the solvent is at least partially removed by the heat of the polymeti7~tion reaction, providing an e~nti~lly solvent-free 5 polymer after the polymeri_ation reaction is e~nti~lly completed. This requires the use of solvents of lower boiling point than that of the acrylic monomlo~.
The acrylic polymes suitable for my inventions have average molecular weights inthe range of 50,000 to 1,000,000 but preferably in the range of 200,000 and 600,000. The Lqefe~l~ acrylic polymers used in this invention are of a cul-lL~ilion that is inherently 10 tacky and suitable for p~ sensitive c~llp~il inn~. The tackiness is achieved by using alkyl acrylates such as butyl acrylate or its higher homologues as co-nlollul~lers in the polyll~f l i~ .lion, as known in the art. The polymer further is provided with functional groups that make the polymer suitable for cro~linking to provide an elastic m~t.ori~l Such suitable functional groups are introduced through co-monomer~, or by function~ql;7ing the polymers 15 through the grafting of such functional groups. A plefell~l reactive group is the anhydride filn~tion~lity. If maleic anhydride is used as a co-monoml-r in the polymerization, a concentration of maleic anhydride in the monom.or n~ e is in the range of .1 to 20% by weight is generally acceptable, but between 0.5 and 5% is pl~f~,~d for a ~ sel~iLive product. High ~IopolLions of maleic anhydride cause ..~ ble hardness in the final 20 product.
The cro~linking agent for the polymer is a m~tPri~l that reacts with the anhydride functic.n~lity on that acrylic polymer. The cr~linking is achieved with a m~t~ri~l cont~ining one or more of the groups C-NH2 or C-NHRl, whereby Rl is an alkyl group or a substitlltYl alkyl group, and wherein said alkyl group may have a furdler functionality 25 attached to itself, such as an ester functional-ity. The rate of cro~linking is ~l~.t. ,..il.~d by the type and degree of substitlltion on the nitrogen atom in that silane; the rate is highest when both substitu~nt~ are l~og~;ll. In my invention, cr~linking at a suitable rate to allow the ploce~ g of the formul~tion is achieved by the addition to that anhydride-217148~
modified polymer of a mAteriAl which co~ s such p~ or secondary amino groupand also a silane group of the general formula -Si-(OR)n, wherein n = 3, and wherein the -RgroupsatelyL -~lly methoxy-OCH3, orethoxy-CH2CH3.
A desirable mAtrriAl of that structure is the ~A.1-lition product of an alkylacrylate such S as ethylacrylate and gamma-amino~I~yll~ oxysiloxane, which consists partially of the isomer HN -CH2CH2CH2 Si ( OCH2CH3)3 o The mAtPriAl is suitable for the production of a cellular pl~bu,e-scnsitive product.
A cro~clinl~-l tacky cellular acrylic mAt~riAl is o~tail,cd by adding a ct~linking agent and by providing a source of a gaseous col~ ,ent.
The unexpected and useful finding is that the use of grAnlllAr mAtrriAl~, such ~ silica in comhinAtion with the acrylic polymer and an amino-functional silane reagent, provides a 15 process for the ptoduction of a cr~link~1 cellular ~ e-sc~ ive desicc~ting product.
The cellular c~m~iilion is preferably achieved by the addition of molecular sieve adso~ ,l, specifically the Molecular Sieves supplied ftom the Union Carbide/UOP
C~ . A further ~ ing and novel finding is that cr~linking and foaming is achieved at prActir~l and suitable rates at ambient tel"p~.~ture, although both can be 20 accelerated at elevated tel~ lu,~ The formlllAt~d mAt~.tiAl based on such a plocebb can be extruded before ~ignifi(~nt cr~linking and foa~ g has occurred.
The suitable Molecular Sieve can be of a wide range of pore structutes, but is preferably of a nomin~l pore ~ m~ter be~ 3 to 10 Angb11~lls, ~ provided by the Molecular Sieves 3A, 4A or 13X. The moisture content of the particulate mAtrriAl is in the 25 range of 0.1 to 15%, and preferably in the range of 0.1 o 5%; it should not exceed l5~Zo if the f~rmlllAtion is to be used as a desicc-Ating mAtrriAl. The amount of Molecular Sieve in the f~rmlllAtion is in the range of 1 to 200 parts per 100 parts of the polymer but is preferentially between S and 50 parts. The Molecular Sieve thus provides the final formlllAtion with an adsorption function such as the removal of water from its ~llvihul)~ t, but also provides a process for the formation of a crQsxlinl~l cellular structure.
The acrylic polymer may contain some moixt.lre, but the upper limit of the moix~lre content of the acrylic polymer should not exceed 2 %. Where required, the fc.rmlllAtion may S also c s~ i ~ al)~rop~ e additional resins to modify the tackiness of the product, may .I..p1 i.~ adhesion promoters, as well as antidegrA.lAnt~ to increase the long-term stability of the product.
Finely divided inorganic filler(s) e.g. calcium carbonate, zinc oxide, barytes, talc or others ( and niL~lules) may be included to improve the ploce~ixil-g and h~n-lling plo~llies of the product. SllbstAntiAl amounts of filler may be used, i.e. up to 100 parts per weight of the polymer formlllAtion, but plcf. ll~ amounts between S and 20 parts, since at higher levels the flexibility of the product is reduced. If desired, finely divided carbon black or other pi~mentx may be included to provide the desirable colour or tint. Recall~e of the stability of acrylic polymers to heat and oxidative degradation, the products of my invention are suitable as an ell./hol .1. ~PntAlly ~i~t~lt sealant and as mAteriAlx for the desiccation of closed systems such as sealed inx~llAtP~ window systems.
F.~mrle I
tion of the Acrylic Polymer of Low Solvent Level. A polymeri7Ation reactor typical for the production of liquid acrylic polymers in solvent is used. To the reactor is added 400 g of ethyl acetate solvent which is heated to reflux. The reactor is equipped with two reservoirs. The first reservoir colllaills 3880 g of the monomPr butyl acrylate in which is dissolved 60 g of maleic anhydride, and 5.2 g of lauryl nlelca~ as a chain lldl~rtl agent. The second reservoir CUlll~linS a solution of the initiAtors for the thPrmAl polymPri7Ation, 48 g of lauryl peroxide and 12 g of ethyl-3,3~i(t-~ll~ y) butyrate, in 480 g of ethyl acetate. Two streams of the reagents from both reservoirs are added in a controlled way to ensure the l~nl~e~ ul~; mAintAinC a steady removal of the ethyl acetate solvent ~ the cooling in the contlPnxPr is discol.~ P~1 The monomer~ are added 8 2171~8~
over a period of 110 minllt~Pe and the initi~tor over 120 minlltP~ Some heating of the reaction ve~el may be required to increase the rate of solvent removal during the poly~ l ;on When the polymPri7~ti~ n ttn,~r&~ has reached 140 C, further heating is required until the range of 170-180 C is reached, at which the solvent is e~ llyS cc~ pl_tely removed from the polymer. The ethylacetate content is then le~ than 1%.
F,~mple II
Preparation of the crosslinking agent for the acrylic polymer. Equimolar amountsof ethyl acrylate and gamma-amino~ ;cthoxysilane are combinP~ and mixed for 10 a~ Aillldtely S l~ c under the exclusion of nl~ . The reaction is exoth.-rmic. The tcl~ dtul~ of the solution is l..~ .P~1 during the mixing and for another hour at below 60 centigr~d~P. The product is stored in a closed cont~inpr to reduce the eA~iulc to iX~
1S F.~mple m Preparation of a Pressure~ensitive Desiccating Product: To lOOg of a copolymer of butyl acrylate and maleic anhydride of the ~lopulLion of 98.5:1.5 and of an average molecular weight of 300,000 is added 100 g of molecular sieve ad~c lI,ent and lg of the equimolar addition product of ethyl acrylate and gamma-all~i~ p~ lllicthoxysilane as 20 described in Example II. The m~tPri~l is mixed at ambient tenlpeld~ until the powder is di~cd, and is then extruded in the desirable shape onto a s~lbstr~te such as a release paper from which it can be removed when later applied. The m~tPri~l develops its cellular structure on storage in a sealed container, and is an elastic and plG~u~ scnsitive adhesive.
F.~mple IV
Preparation of a Non-tacky De~2~ -~ing Product: The process is desc~ibed as in Example m, except that 2 grams of the ad-liti- n product of ethylacrylate and gamma-amin~ icthoxysilane, described in Example lL is added to the n~L~
Claims (17)
1. A process for polymerization of acrylic monomers in which essentially all of the solvent means in which said polymerization is initiated and proceeds is being removed from the reaction mixture over the period in which essentially all monomer conversion proceeds.
2. A process according to claim 1 wherein the acrylic polymer producedis of an average molecular weight in the range from 200,000 to 1,000,000.
3. A desiccating means comprising a desiccant material and a crosslinking means dispersed in a polymer, whereby said polymer is provided with pendant anhydride functional groups reactive with said crosslinking agent.
4. A desiccating means according to claim 3 wherein said polymer is the product of the copolymerization of acrylic monomers with an organic anhydride.
5. A desiccating means according to claim 3 wherein said polymer is the product of the copolymerization of acrylic monomers with maleic anhydride.
6. A desiccating means according to any one of the claims 3 to 5 wherein said polymer is a pressure-sensitive acrylic polymer.
7. A desiccating means according to any one of the claims 3 to 6 wherein said crosslinking means is an alkyltrialkoxysilane of which the alkyl group is functionalized with at least one amino group.
8. A desiccant means according to any one of the claims 3 to 7 of which the desiccant agent is molecular sieve adsorbent.
9. A desiccating means according to any one of the claims 3 to 8 in which the concentration of the desiccating agent is between 2 and 200 parts per 100 parts of polymer, in addition to other formulation ingredients.
10. A process for producing a crosslinked tacky and pressure-sensitive cellular desiccating means by providing a dispersed gaseous substance in the material described in any one of the claims 3 to 9.
11. A process for producing a crosslinked tacky and pressure-sensitive cellular desiccating means by the elimination of a gaseous substance from a component dispersed in the materials described in any one of the claims 3 to 9.
12. A process for producing a crosslinked tacky and pressure-sensitive cellular desiccating means according to claim 11 wherein the gaseous substance is eliminated from the molecular sieve adsorbent.
13. A pressure-sensitive cellular material comprising an acrylic polymer provided with pendant anhydride groups and comprising further a crosslinking agent for said polymer.
14. A pressure-sensitive cellular desiccating means comprising first acrosslinked acrylic polymer and second a desiccating material.
15. An acrylic pressure-sensitive cellular material as described in any one of the claims 13 or 14 whereby the crosslinking agent is an organic amine.
16. An acrylic pressure-sensitive cellular material as described in any one of the claims 13 or 14 whereby the crosslinking agent is an amino-functionalizedalkylsilane.
17. A material according to any one of the claims 3 to 9 or 13 to 16 which encloses a spacer means that limits the thickness to which said material deforms under a load.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002171483A CA2171483A1 (en) | 1996-03-11 | 1996-03-11 | Foamed acrylic desiccant |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002171483A CA2171483A1 (en) | 1996-03-11 | 1996-03-11 | Foamed acrylic desiccant |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2171483A1 true CA2171483A1 (en) | 1997-09-12 |
Family
ID=4157726
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002171483A Abandoned CA2171483A1 (en) | 1996-03-11 | 1996-03-11 | Foamed acrylic desiccant |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2171483A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014031383A1 (en) | 2012-08-20 | 2014-02-27 | Henkel Corporation | Moisture curable polyacrylates |
-
1996
- 1996-03-11 CA CA002171483A patent/CA2171483A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014031383A1 (en) | 2012-08-20 | 2014-02-27 | Henkel Corporation | Moisture curable polyacrylates |
| CN104837874A (en) * | 2012-08-20 | 2015-08-12 | 汉高知识产权控股有限责任公司 | Moisture curable polyacrylates |
| JP2015531767A (en) * | 2012-08-20 | 2015-11-05 | ヘンケル アイピー アンド ホールディング ゲゼルシャフト ミット ベシュレンクテル ハフツング | Moisture curable polyacrylate |
| EP2885325A4 (en) * | 2012-08-20 | 2016-08-17 | Henkel IP & Holding GmbH | Moisture curable polyacrylates |
| CN104837874B (en) * | 2012-08-20 | 2016-10-26 | 汉高知识产权控股有限责任公司 | Moisture cured polyacrylate |
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| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |