CA2142195A1 - Deacidification of cellulosic material - Google Patents
Deacidification of cellulosic materialInfo
- Publication number
- CA2142195A1 CA2142195A1 CA 2142195 CA2142195A CA2142195A1 CA 2142195 A1 CA2142195 A1 CA 2142195A1 CA 2142195 CA2142195 CA 2142195 CA 2142195 A CA2142195 A CA 2142195A CA 2142195 A1 CA2142195 A1 CA 2142195A1
- Authority
- CA
- Canada
- Prior art keywords
- composition
- methanol
- diluent
- magnesium
- deacidification
- 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
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H25/00—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
- D21H25/18—After-treatment of paper not provided for in groups D21H17/00 - D21H23/00 of old paper as in books, documents, e.g. restoring
Abstract
A composition for deacidification of aging cellulosic materials, such as paper, books, documents, works of art, clothing and flags, from library, archive and museum collections is comprised of a carbonated magnesium alkoxide, such as methoxymagnesium methylcarbonate or ethoxymagnesium ethylcarbonate, a solvent, such as methanol or ethanol, and a hydrochlorofluorocarbon and/or a hydrofluorocarbon diluent. The deacidification composition of the present invention may be applied by spraying through a nozzle, by brushing or by immersing the cellulosic material in the deacidification composition.
Description
21~219~
D~'TnTT~ICATION OF ~T~T~T~T~n~3Ic M~TT~DTaT.
FIBI,D OF T~ lnv~
The present invention relates to the field of 5 ~ese1v~tion of cellulosic materials, such as books, documents, works of art, clothing and flags, and in particular, to a process for deacidification of cellulosic materials .
10 R~ OF Ti~S lh ~
There is much concern about the deterioration of aging cellulosic materials, particularly those of library, museum and archive collections . The most signif icant cause of deterioration of cellulosic materials ls acid-catalyzed 15 hydrolysis of c~ ]lose which results in shortened c~ loc~ molecules, and weak and brittle fibres. There are a number of factors which cause an acidic condition in cellulosic materials including air pollutants, the use of alum in the paper k~n~ process and the degradation 20 products of cellulose and ink.
In an effort to reduce the deterioration of cellulosic materials by acid-catalyzed hydrolysis, researchers have turned their attention to processes for deacidification of c~ lo~ic materials. Attention has been specifically 25 directed to non-aqueous deacidification compositions to neutralize the acidity of the cellulosic materials and to introduce an A 1 kA l; nr~ reserve to inhibit re-acidif ication .
United States Patent Number 3,676,182 (R.D. Smith, July 11, 1972) relates to a process for non-agueous 30 deacidifica~ion of paper using magnesium r ' h~.Y;~ as a deacidif ication agent . The deacidif ication agent is dissolved in methanol to a concentration of about 5 to 11%.
The resultant solution may be diluted with a chlorofluorocarbon, such as trichlorofluoromethane or 35 dichlorodifluu~ n~ to produce a solution of about 1 to 2% magnesium methoxide. The chlorofluorocarbon contributes to rapid evaporation of the solution and 21~2195 imparts hydrophobic properties to ~ ac~ ication solutions conta ining methano 1, thereby m i n i m i ~ i n~ attack on certain inks by methanol. Books and papers may be dipped in the solution or the solution may be applied by brushing or 5 spraying.
However, m-gnP~ m h~Yi~ is t!X~L~ -ly sensitive to water such that even traces of moisture cause immediate hydrolysis and a gelatinous precipitate of magnesium hydroxide which is insoluble in water and inorganic 10 solvents . Unless the paper is suf f iciently dried prior to LL~a~ -nt, pL. ~U' r! hydrolysis of the magnesium methoxide may occur, causing an undesirable glaze of magnesium hydroxide to be formed on the surface of the paper.
Furthermore, the nozzles of spray guns are subject to 15 frequent plugging. The bristles of brushes also become clogged and must be cleaned and dried prior to reuse.
United States Patent Number 3,939,091 (Kelly, G.B., February 17, 1976~ discloses a composition for use in the deacidification of paper which c~v~:~r - the problem of the 20 prior art ~c-a~ ication solutions comprised of magnesium methoxide dissolved in a chlorof luorocarbon . M;l~n~ lm r ~ hnYi~ i8 dissolved in methanol or in a mixture of methanol and trichlorotrifluoroethane (FREONTM TF). Carbon dioxide is then introduced into the solution to produce a 25 colourless 20% methoxymagnesium methylcarbonate solution.
The resultant solution is very tolerant of water compared to solutions of magnesium ~Yi de and does not cause plugging of spray nozzles or gumming of brushes.
~ n;~ n Patent Number 1,147,510 (Smith, R.D., June 7, 30 1983) describes another method for production of methoxymagnesium methylcarbonate. Nagnesium metal is reacted with absolute methanol to produce dried magnesium methoxide. The magnesium ~ is then re-dissolved in methanol containing carbon dioxide to produce a solution of 35 metho,~y~ llm methylcarbonate. The solution is diluted with trichlorotrif luoroethane or dichlorodif luoromethane .
The diluted solution is sprayed or brushed onto papers to 21421g5 deacidify the paper. Alternatively, the paper can be dipped into the solution. This method for preparation of methuxy.l,ayllesium methylcarbonate allows the dry material, namely magnesium ~ , to be prepared prior to 5 delivery to a work site and then re-dissolved in methanol and reacted with carbon dioxide on site.
United States Patent Number 4,860,685 (Smith, R.D., August 29, 1989) and ccLL~ ing ~AnA~iAn Patent Number 1, 272, 018 (July 31, 1990) describe a soft spray system for 10 ~l~A~ if ication of cellulosic materials. A 19~A~ if ication agent, preferably a carbonated magnesium Alkr~Yi~l~, is combined with a chlorofluorocarbon diluent, preferably trichlorotrifluoroethane, and a chlorofluorocarbon gas propellant, preferably dichlorodifluoromethane. Additional 15 ~L~S~-uLizing and propelling may be provided by an inert gas suc~ as nitrogen . The carbonated magnesium A 1 kf~Yi ~1~, such as methoxymagnesium methyl~aLI,u..ate or ethoxymagnesium ethylcarbonate, is produced by dissolving the corr~ p~n~lin ~
magnesium Alk~Y~ in a lower alcohol in the presence of carbon dioxide.
The prior art processes described herein use chlorofluorocarbons since they are substantially unreactive and, as such, pose no direct toxic threat to living organisms. However, these very same characteristics that render chlorofluorocarbons inert pose significant problems in the stratosphere . Chlorof luorocarbons have been recognized as being a major factor responsible for stratospheric ozone depletion and for contributing to the greenhouse effect. Of particular concern is the chlorine which is liberated when the chlorofluorocarbons are e_posed to strong W radiation in the stratosphere. Chlorine depletes ozone by catalyzing its conversion to molecular oYygen. Production and cu._ ~ion of chlorofluuLuuaLbol~s has been substantially reduced and must be eliminated by January 1, 1996 (~op~nhAgen Agreement to amend Montreal Protocol, November 23-25, 1992). Accordingly, a substitute must be found for the chlorofluorocarbon diluent of the 21~2195 prior art compositions.
It i8 an object of the present invention to provide a compo6ition for deacidification of aging cellulosic material comprising a diluent to replace the 5 chlorofluur uuaLbu~l diluents Or the prior art.
8UM~Y OF THE 1~ v b.. I _ According to one aspect of the present invention, there is provided a composition for deacidification of a cellulosic material, comprising a carbonated magnesium ~lk~Y;~.-, a solvent, and a hydrochlorofluorocarbon and/or a hydrof luorocarbon di luent .
According to another aspect of the present invention, there is provided a method for preparing a composition for deacidification of a CPlllllosic material, comprising the steps of r~fl-lY;n~ r-~nps;llm metal in methanol to produce a suspension of magnesium methoxide in methanol; cooling the 6uspension of magnesium methoxide in methanol;
saturating the cooled suspension of magnesium methoxide in methanol with carbon dioxide to produce a solution of methu,~y~ yllesium methylcarbonate in methanol; and diluting the solution of methu~yl,lc.y.lesium methylcarbonate with a hydrochlorofluorocarbon or hydrofluorocarbon diluent.
DT~T~TTT~n DE8CRIPTION OF TIIE: L.~bCI~ JIM~
In accordance with the present invention, the chlorofluorocarbons of the prior art deacidification compositions are replaced with a hydrochlorofluuLuLc~Lbu and/or a hydrofluorocarbon.
3 0 The present inventor has discovered that carbonated magnesium llko~ le de~ ication agents are soluble in hydrochlorofluuLuui~Ll,ulls and/or hydrofluorocarbons and that the resultant compositions are effective in deacidification of cellulosic materials. Moreover, hydrochlorofluorocarbons and hydrofluorocarbons are subctantially inert and are not toxic.
The use of hydrochlorofluorocarbons and hydrofluorocarbons to replace the chlorofluorocarbons of the prior art compositions substantially reduces the available number of chlorine ions which may be liberated upon ~.L~O;jw~ e to strong W radiation in the stratosphere, 5 as compared with the prior art chlorof luorocarbons .
Fur~hl ~, the ~L~sen~e of IIYdLOY~II renders the ~ _ ' more reactive so that it is more likely to be ~1P~ - sed before it reaches the stratosphere. Noreover, the rate of de -~ition is higher than that of chloroflu<,lo~LI,ul,s which have a lifetime of about 60 ~o 100 years. nhile regulations will eventually prohibit the use of hydrochlorofluorocarbon6, the phase-out 5rhp~ e for c.-._ Lion only begins on January 1, 1996 with elimination !:~hP,l.ll P~ for 2030 (Copenhagen A~L~ L to amend Montreal Pro~ocol, N~ 23-25, 1992). There are no such regulations in place with respect to hydrof luorocarbons .
The hydrochlorofluorocarbon and/or hydrofluorocarbon act as a diluent for delivery of a dP~r~ ication agent and a solvent to aging c~ l osic materials. Elereinafter, 20 the term "cellulosic material" will be understood to include paper, books, documents, archival records, maps, worlcs of art and articles made from cotton and/or linen including clothing and f lags .
A suitable deacidif ication agent is a carbonated 25 magnesium AlkoY;dP, such as methoxymagnesium methylcarbonate or etho.~y."ay.lesium ethylcarl:~onate.
One method for pro~ tirln of methoxymagnesium methylcarbonate is described in United States Patent Number 3,939,091. Ml~nPsium metal is refluxed in methanol to give 30 a suspension of magnesium methoxide in methanol. After cooling, the s~ pPn~ of magnesium methoxide in methanol is saturated with carbon dioxide to form a solution of methc~y",~y~lesium methylcarbonate in methanol.
Nethoxymagnesium methylcarbonate and ethoxymagnesium 35 ethylcarbonate may also be produced as described in ~ ln;~ n Patent Number 1,147,510 wherein magnesium metal is reacted with methanol or ethanol to produce r-~nPsillm 214219~
methoxide or magnesium eth~)yi~lo~ respectively. The resultant solution is dried, by a method known to those skilled in the art, to form a dried powder of magnesium ~lknY;~le. The dried magnesium r '' 'rlo or r-gnoclllm 5 ethoxide is subsequently added to methanol or ethanol in the presence of carbon dioxide to form methoxymagnesium methylcarbonate or ethu,,y.l~a~..esium ethylcarbonate, respectively .
Preferably, the ~;aLl,u..ated magnesium :Rlkr Yl~e i8 methoxymagnesium methylcarbonate or ethoxymagnesium ethyl~aLbol~ate~ with methoxy --~rlosillm methylcarbonate being the most preferable. ~owever, it will be appreciated by those skilled in the art that other suitable carbonated magnesium ~lk~lYirlos can be prepared by either of the above-mentioned methods using other solvents to produce the r~ur ~ nrJ homologs of methoxy~magnesium methylcarbonate.
The solvent must however be evaluated for the potential for damage to the h~n-1inqs, inks, etc. of the material being treated.
The concentration of carbonated magnesium alk~lYirlo in the solvent is suitably in the range of from about 5 to 20%
(w/v). Preferably, the cu-.c~ ation is about 20% (w/v).
The resultant solution of carbonated magnesium alkoxide in solvent is diluted with a hydrochlorofluorocarbon and/or a hydrofluorocarbon to yield a concentratior: of carbonated magnesium ~lkoYido in the range of from about 0.1 to 2% (w/v). Preferably, the cu..ct~-L atiOn of carbonated magnesium ~lkoyir~o in the diluted solution is in the range of from about O . 5 to 1. 5%
30 (w/v). The hydrochlorofluorocarbon and/or hydrofluorocarbon diluent contributes to rapid evaporation of the solution and minimi70~; attack on certain inks by the solvent. It is desirable that the r_o~.c~l.LLation of solvent in the rloA~ir~lfication composition of the present invention 35 is as low as possible. Preferably, the curlcr:llLr ation of solvent in the diluted solution is less than about 59 (v/v).
214219~
.--Suitable hydrochlorofluolouclL},ol~ diluents are di~luorochloroethane, trif luorochloroethane, tetrafluorochloroethane, hydrochlorofluo~o},Lu~anes and hydrochlorof luorobutanes . A particularly suitable 5 hydrochlorofluorocarbon diluent is 1,1-dichloro-1-fluoroethane. ChlorodifluuLl AnP may be added as a co-diluent to increase the vapour ~l~5~UL~ of the mixture, thereby increasing evaporation of the solution.
Preferably, the c.,l.c~ Lc.tion of chlorodifluul~ ~AnP
10 added as a co-diluent is not greater than about 10% (v/v), in view of the high vapour ~L~:lSr~ULt: of chlorodif luoromethane .
Suitable hydrofluuLù~lLbulls are fluorinated methanes, ethanes, propane~ and butanes.
The deacidification composition of the present invention may also include additives, such as a plasticizer, to reduce the brittleness of the cellulosic material .
The ~l~Ari-lification composition of the present invention may be applied to CPll-]lofiic materials in a manner known to those skilled in the art, for example by spraying with a spray gun or an aerosol can, by brushing or by dipping the cPllllloc~r materials into the deacidification composition.
Preferably, the method for ~P~A~rill~fication of cPlllllogic materials is as follows.
The cellulosic materials are placed in a vessel capable of withstanding a vacuum. The vessel is sealed and evacuated with a vacuum pump. Preferably, the water content of the cPl l-llo~:ic materials is reduced from a normal eguilibrium moisture content of from about 5 to 6~
to a residual moisture content of from about 1 to 2~6 under vacuum. The (lP~A~ri(li fication composition of the present invention is then introduced to the vessel and the cellulosic materials are i ~ed in the composition for a time sufficient to allow penetration of the composition into the cellulosic materials.
If desired, a positive ~res~7uL~, for example by introduction of carbon dioxide or another gas, may be applied to the vessel to increase the penetration of the composition .
The treatment may be cqn~ tPd at room temperature or greater. It will be appreciated by those skilled in the art that the t: a LUL 3 must not be 80 great as to damage the cellulosic material being treated.
At the end of the LL~i L, the vessel is drained and a vacuum is applied to the vessel to recover âny 1l ;n;n~
solvent and diluent. The cellulosic material is then removed from the vessel and is allowed to air dry in a fumehood. This method is particularly advantageous in that it permits simultaneous ~L~at L of a large number of books, for example. Furth ~, the solution can be readily ~cuv~L.d from the vessel.
Alternatively, the ~lPat~ ;fication composition of the present invention may be applied by the soft spray system described in United States Patent Number 4,860,685, discussed hereinabove. It will be appreciated by those skilled in the art that other methods of contacting the ~-Pl ~ osic materials with the deacidification composition of ~he present invention are also suitable. For example, it is not nPcP~SAry that the cellulosic material be dried under a vacuum prior to contacting with the clPar~ ;fication composition of the present invention. The cellulosic material may also be contacted with the deacidification composition of the present invention by brushing or spraying .
The deacidification composition of the present invention may also be used in the method and apparatus described in ~AnA~iAn Patent Application Number 2,009,621 (Eggersdorfer, R. et al, pllhl;~hPd August 11, 1990).
~An?l~l;An Pa~ent Application Number 2,009,621 relates to a method and apparatus for ~lPa~ ; fication of cellulosic materials by pre-drying the paper by high frequency radiation in a vacuum, neutrali~ing with a deacidification 21~2195 .
solution and evaporating the solvent in a vacuum with high fre~uency radiztion. The ~ aLclLu6 described i8 a single treatment chamber ~or the pre-drying, neutralizing and ~:v~lpuL~ting steps in an enclosure for total solvent 5 recovery.
D~'TnTT~ICATION OF ~T~T~T~T~n~3Ic M~TT~DTaT.
FIBI,D OF T~ lnv~
The present invention relates to the field of 5 ~ese1v~tion of cellulosic materials, such as books, documents, works of art, clothing and flags, and in particular, to a process for deacidification of cellulosic materials .
10 R~ OF Ti~S lh ~
There is much concern about the deterioration of aging cellulosic materials, particularly those of library, museum and archive collections . The most signif icant cause of deterioration of cellulosic materials ls acid-catalyzed 15 hydrolysis of c~ ]lose which results in shortened c~ loc~ molecules, and weak and brittle fibres. There are a number of factors which cause an acidic condition in cellulosic materials including air pollutants, the use of alum in the paper k~n~ process and the degradation 20 products of cellulose and ink.
In an effort to reduce the deterioration of cellulosic materials by acid-catalyzed hydrolysis, researchers have turned their attention to processes for deacidification of c~ lo~ic materials. Attention has been specifically 25 directed to non-aqueous deacidification compositions to neutralize the acidity of the cellulosic materials and to introduce an A 1 kA l; nr~ reserve to inhibit re-acidif ication .
United States Patent Number 3,676,182 (R.D. Smith, July 11, 1972) relates to a process for non-agueous 30 deacidifica~ion of paper using magnesium r ' h~.Y;~ as a deacidif ication agent . The deacidif ication agent is dissolved in methanol to a concentration of about 5 to 11%.
The resultant solution may be diluted with a chlorofluorocarbon, such as trichlorofluoromethane or 35 dichlorodifluu~ n~ to produce a solution of about 1 to 2% magnesium methoxide. The chlorofluorocarbon contributes to rapid evaporation of the solution and 21~2195 imparts hydrophobic properties to ~ ac~ ication solutions conta ining methano 1, thereby m i n i m i ~ i n~ attack on certain inks by methanol. Books and papers may be dipped in the solution or the solution may be applied by brushing or 5 spraying.
However, m-gnP~ m h~Yi~ is t!X~L~ -ly sensitive to water such that even traces of moisture cause immediate hydrolysis and a gelatinous precipitate of magnesium hydroxide which is insoluble in water and inorganic 10 solvents . Unless the paper is suf f iciently dried prior to LL~a~ -nt, pL. ~U' r! hydrolysis of the magnesium methoxide may occur, causing an undesirable glaze of magnesium hydroxide to be formed on the surface of the paper.
Furthermore, the nozzles of spray guns are subject to 15 frequent plugging. The bristles of brushes also become clogged and must be cleaned and dried prior to reuse.
United States Patent Number 3,939,091 (Kelly, G.B., February 17, 1976~ discloses a composition for use in the deacidification of paper which c~v~:~r - the problem of the 20 prior art ~c-a~ ication solutions comprised of magnesium methoxide dissolved in a chlorof luorocarbon . M;l~n~ lm r ~ hnYi~ i8 dissolved in methanol or in a mixture of methanol and trichlorotrifluoroethane (FREONTM TF). Carbon dioxide is then introduced into the solution to produce a 25 colourless 20% methoxymagnesium methylcarbonate solution.
The resultant solution is very tolerant of water compared to solutions of magnesium ~Yi de and does not cause plugging of spray nozzles or gumming of brushes.
~ n;~ n Patent Number 1,147,510 (Smith, R.D., June 7, 30 1983) describes another method for production of methoxymagnesium methylcarbonate. Nagnesium metal is reacted with absolute methanol to produce dried magnesium methoxide. The magnesium ~ is then re-dissolved in methanol containing carbon dioxide to produce a solution of 35 metho,~y~ llm methylcarbonate. The solution is diluted with trichlorotrif luoroethane or dichlorodif luoromethane .
The diluted solution is sprayed or brushed onto papers to 21421g5 deacidify the paper. Alternatively, the paper can be dipped into the solution. This method for preparation of methuxy.l,ayllesium methylcarbonate allows the dry material, namely magnesium ~ , to be prepared prior to 5 delivery to a work site and then re-dissolved in methanol and reacted with carbon dioxide on site.
United States Patent Number 4,860,685 (Smith, R.D., August 29, 1989) and ccLL~ ing ~AnA~iAn Patent Number 1, 272, 018 (July 31, 1990) describe a soft spray system for 10 ~l~A~ if ication of cellulosic materials. A 19~A~ if ication agent, preferably a carbonated magnesium Alkr~Yi~l~, is combined with a chlorofluorocarbon diluent, preferably trichlorotrifluoroethane, and a chlorofluorocarbon gas propellant, preferably dichlorodifluoromethane. Additional 15 ~L~S~-uLizing and propelling may be provided by an inert gas suc~ as nitrogen . The carbonated magnesium A 1 kf~Yi ~1~, such as methoxymagnesium methyl~aLI,u..ate or ethoxymagnesium ethylcarbonate, is produced by dissolving the corr~ p~n~lin ~
magnesium Alk~Y~ in a lower alcohol in the presence of carbon dioxide.
The prior art processes described herein use chlorofluorocarbons since they are substantially unreactive and, as such, pose no direct toxic threat to living organisms. However, these very same characteristics that render chlorofluorocarbons inert pose significant problems in the stratosphere . Chlorof luorocarbons have been recognized as being a major factor responsible for stratospheric ozone depletion and for contributing to the greenhouse effect. Of particular concern is the chlorine which is liberated when the chlorofluorocarbons are e_posed to strong W radiation in the stratosphere. Chlorine depletes ozone by catalyzing its conversion to molecular oYygen. Production and cu._ ~ion of chlorofluuLuuaLbol~s has been substantially reduced and must be eliminated by January 1, 1996 (~op~nhAgen Agreement to amend Montreal Protocol, November 23-25, 1992). Accordingly, a substitute must be found for the chlorofluorocarbon diluent of the 21~2195 prior art compositions.
It i8 an object of the present invention to provide a compo6ition for deacidification of aging cellulosic material comprising a diluent to replace the 5 chlorofluur uuaLbu~l diluents Or the prior art.
8UM~Y OF THE 1~ v b.. I _ According to one aspect of the present invention, there is provided a composition for deacidification of a cellulosic material, comprising a carbonated magnesium ~lk~Y;~.-, a solvent, and a hydrochlorofluorocarbon and/or a hydrof luorocarbon di luent .
According to another aspect of the present invention, there is provided a method for preparing a composition for deacidification of a CPlllllosic material, comprising the steps of r~fl-lY;n~ r-~nps;llm metal in methanol to produce a suspension of magnesium methoxide in methanol; cooling the 6uspension of magnesium methoxide in methanol;
saturating the cooled suspension of magnesium methoxide in methanol with carbon dioxide to produce a solution of methu,~y~ yllesium methylcarbonate in methanol; and diluting the solution of methu~yl,lc.y.lesium methylcarbonate with a hydrochlorofluorocarbon or hydrofluorocarbon diluent.
DT~T~TTT~n DE8CRIPTION OF TIIE: L.~bCI~ JIM~
In accordance with the present invention, the chlorofluorocarbons of the prior art deacidification compositions are replaced with a hydrochlorofluuLuLc~Lbu and/or a hydrofluorocarbon.
3 0 The present inventor has discovered that carbonated magnesium llko~ le de~ ication agents are soluble in hydrochlorofluuLuui~Ll,ulls and/or hydrofluorocarbons and that the resultant compositions are effective in deacidification of cellulosic materials. Moreover, hydrochlorofluorocarbons and hydrofluorocarbons are subctantially inert and are not toxic.
The use of hydrochlorofluorocarbons and hydrofluorocarbons to replace the chlorofluorocarbons of the prior art compositions substantially reduces the available number of chlorine ions which may be liberated upon ~.L~O;jw~ e to strong W radiation in the stratosphere, 5 as compared with the prior art chlorof luorocarbons .
Fur~hl ~, the ~L~sen~e of IIYdLOY~II renders the ~ _ ' more reactive so that it is more likely to be ~1P~ - sed before it reaches the stratosphere. Noreover, the rate of de -~ition is higher than that of chloroflu<,lo~LI,ul,s which have a lifetime of about 60 ~o 100 years. nhile regulations will eventually prohibit the use of hydrochlorofluorocarbon6, the phase-out 5rhp~ e for c.-._ Lion only begins on January 1, 1996 with elimination !:~hP,l.ll P~ for 2030 (Copenhagen A~L~ L to amend Montreal Pro~ocol, N~ 23-25, 1992). There are no such regulations in place with respect to hydrof luorocarbons .
The hydrochlorofluorocarbon and/or hydrofluorocarbon act as a diluent for delivery of a dP~r~ ication agent and a solvent to aging c~ l osic materials. Elereinafter, 20 the term "cellulosic material" will be understood to include paper, books, documents, archival records, maps, worlcs of art and articles made from cotton and/or linen including clothing and f lags .
A suitable deacidif ication agent is a carbonated 25 magnesium AlkoY;dP, such as methoxymagnesium methylcarbonate or etho.~y."ay.lesium ethylcarl:~onate.
One method for pro~ tirln of methoxymagnesium methylcarbonate is described in United States Patent Number 3,939,091. Ml~nPsium metal is refluxed in methanol to give 30 a suspension of magnesium methoxide in methanol. After cooling, the s~ pPn~ of magnesium methoxide in methanol is saturated with carbon dioxide to form a solution of methc~y",~y~lesium methylcarbonate in methanol.
Nethoxymagnesium methylcarbonate and ethoxymagnesium 35 ethylcarbonate may also be produced as described in ~ ln;~ n Patent Number 1,147,510 wherein magnesium metal is reacted with methanol or ethanol to produce r-~nPsillm 214219~
methoxide or magnesium eth~)yi~lo~ respectively. The resultant solution is dried, by a method known to those skilled in the art, to form a dried powder of magnesium ~lknY;~le. The dried magnesium r '' 'rlo or r-gnoclllm 5 ethoxide is subsequently added to methanol or ethanol in the presence of carbon dioxide to form methoxymagnesium methylcarbonate or ethu,,y.l~a~..esium ethylcarbonate, respectively .
Preferably, the ~;aLl,u..ated magnesium :Rlkr Yl~e i8 methoxymagnesium methylcarbonate or ethoxymagnesium ethyl~aLbol~ate~ with methoxy --~rlosillm methylcarbonate being the most preferable. ~owever, it will be appreciated by those skilled in the art that other suitable carbonated magnesium ~lk~lYirlos can be prepared by either of the above-mentioned methods using other solvents to produce the r~ur ~ nrJ homologs of methoxy~magnesium methylcarbonate.
The solvent must however be evaluated for the potential for damage to the h~n-1inqs, inks, etc. of the material being treated.
The concentration of carbonated magnesium alk~lYirlo in the solvent is suitably in the range of from about 5 to 20%
(w/v). Preferably, the cu-.c~ ation is about 20% (w/v).
The resultant solution of carbonated magnesium alkoxide in solvent is diluted with a hydrochlorofluorocarbon and/or a hydrofluorocarbon to yield a concentratior: of carbonated magnesium ~lkoYido in the range of from about 0.1 to 2% (w/v). Preferably, the cu..ct~-L atiOn of carbonated magnesium ~lkoyir~o in the diluted solution is in the range of from about O . 5 to 1. 5%
30 (w/v). The hydrochlorofluorocarbon and/or hydrofluorocarbon diluent contributes to rapid evaporation of the solution and minimi70~; attack on certain inks by the solvent. It is desirable that the r_o~.c~l.LLation of solvent in the rloA~ir~lfication composition of the present invention 35 is as low as possible. Preferably, the curlcr:llLr ation of solvent in the diluted solution is less than about 59 (v/v).
214219~
.--Suitable hydrochlorofluolouclL},ol~ diluents are di~luorochloroethane, trif luorochloroethane, tetrafluorochloroethane, hydrochlorofluo~o},Lu~anes and hydrochlorof luorobutanes . A particularly suitable 5 hydrochlorofluorocarbon diluent is 1,1-dichloro-1-fluoroethane. ChlorodifluuLl AnP may be added as a co-diluent to increase the vapour ~l~5~UL~ of the mixture, thereby increasing evaporation of the solution.
Preferably, the c.,l.c~ Lc.tion of chlorodifluul~ ~AnP
10 added as a co-diluent is not greater than about 10% (v/v), in view of the high vapour ~L~:lSr~ULt: of chlorodif luoromethane .
Suitable hydrofluuLù~lLbulls are fluorinated methanes, ethanes, propane~ and butanes.
The deacidification composition of the present invention may also include additives, such as a plasticizer, to reduce the brittleness of the cellulosic material .
The ~l~Ari-lification composition of the present invention may be applied to CPll-]lofiic materials in a manner known to those skilled in the art, for example by spraying with a spray gun or an aerosol can, by brushing or by dipping the cPllllloc~r materials into the deacidification composition.
Preferably, the method for ~P~A~rill~fication of cPlllllogic materials is as follows.
The cellulosic materials are placed in a vessel capable of withstanding a vacuum. The vessel is sealed and evacuated with a vacuum pump. Preferably, the water content of the cPl l-llo~:ic materials is reduced from a normal eguilibrium moisture content of from about 5 to 6~
to a residual moisture content of from about 1 to 2~6 under vacuum. The (lP~A~ri(li fication composition of the present invention is then introduced to the vessel and the cellulosic materials are i ~ed in the composition for a time sufficient to allow penetration of the composition into the cellulosic materials.
If desired, a positive ~res~7uL~, for example by introduction of carbon dioxide or another gas, may be applied to the vessel to increase the penetration of the composition .
The treatment may be cqn~ tPd at room temperature or greater. It will be appreciated by those skilled in the art that the t: a LUL 3 must not be 80 great as to damage the cellulosic material being treated.
At the end of the LL~i L, the vessel is drained and a vacuum is applied to the vessel to recover âny 1l ;n;n~
solvent and diluent. The cellulosic material is then removed from the vessel and is allowed to air dry in a fumehood. This method is particularly advantageous in that it permits simultaneous ~L~at L of a large number of books, for example. Furth ~, the solution can be readily ~cuv~L.d from the vessel.
Alternatively, the ~lPat~ ;fication composition of the present invention may be applied by the soft spray system described in United States Patent Number 4,860,685, discussed hereinabove. It will be appreciated by those skilled in the art that other methods of contacting the ~-Pl ~ osic materials with the deacidification composition of ~he present invention are also suitable. For example, it is not nPcP~SAry that the cellulosic material be dried under a vacuum prior to contacting with the clPar~ ;fication composition of the present invention. The cellulosic material may also be contacted with the deacidification composition of the present invention by brushing or spraying .
The deacidification composition of the present invention may also be used in the method and apparatus described in ~AnA~iAn Patent Application Number 2,009,621 (Eggersdorfer, R. et al, pllhl;~hPd August 11, 1990).
~An?l~l;An Pa~ent Application Number 2,009,621 relates to a method and apparatus for ~lPa~ ; fication of cellulosic materials by pre-drying the paper by high frequency radiation in a vacuum, neutrali~ing with a deacidification 21~2195 .
solution and evaporating the solvent in a vacuum with high fre~uency radiztion. The ~ aLclLu6 described i8 a single treatment chamber ~or the pre-drying, neutralizing and ~:v~lpuL~ting steps in an enclosure for total solvent 5 recovery.
Claims (20)
1. A composition for deacidification of a cellulosic material, comprising a carbonated magnesium alkoxide, a solvent, and a hydrochlorofluorocarbon and/or a hydrofluorocarbon diluent.
2. A composition according to claim 1, wherein the hydrochlorofluorocarbon diluent is selected from the group consisting of difluorochloroethane, trifluorochloroethane, tetrafluorochloroethane, hydrochlorofluoropropanes and hydrochlorofluorobutanes.
3. A composition according to claim 2, further comprising chlorodifluoromethane as a co-diluent.
4. A composition according to claim 3, wherein the concentration of chlorodifluoromethane is not greater than about 10% (v/v).
5. A composition according to claim 1, wherein the hydrofluorocarbon diluent is selected from the group consisting of fluorinated methanes, ethanes, propanes and butanes.
6. A composition according to claim 1, wherein the carbonated magnesium alkoxide is methoxymagnesium methylcarbonate.
7. A composition according to claim 1, wherein the carbonated magnesium alkoxide is is ethoxymagnesium ethylcarbonate.
8. A composition according to claim 1, wherein the concentration of the carbonated magnesium alkoxide is in the range of from about 0.1 to 2% (w/v).
9. A composition according to claim 1, wherein the concentration of the carbonated magnesium alkoxide is in the range of from about 0.5 to 1.5% (w/v).
10. A composition according to claim 1, wherein the solvent is methanol.
11. A composition according to claim 1, wherein the solvent is ethanol.
12. A composition according to claim 1, wherein the concentration of solvent is less than about 5% (v/v).
13. A method for preparing a composition for deacidification of a cellulosic material, comprising the steps of refluxing magnesium metal in methanol to produce a suspension of magnesium methoxide in methanol; cooling the suspension of magnesium methoxide in methanol;
saturating the cooled suspension of magnesium methoxide in methanol with carbon dioxide to produce a solution of methoxymagnesium methylcarbonate in methanol; and diluting the solution of methoxymagnesium methylcarbonate with a hydrochlorofluorocarbon or hydrofluorocarbon diluent.
saturating the cooled suspension of magnesium methoxide in methanol with carbon dioxide to produce a solution of methoxymagnesium methylcarbonate in methanol; and diluting the solution of methoxymagnesium methylcarbonate with a hydrochlorofluorocarbon or hydrofluorocarbon diluent.
14. A method according to claim 13, wherein the hydrochlorofluorocarbon diluent is selected from the group consisting of difluorochloroethane, trifluorochloroethane, tetrafluorochloroethane, hydrochlorofluoropropanes and hydrochlorofluorobutanes.
15. A method according to claim 14, wherein chlorodifluoromethane is used as a co-diluent.
16. A method according to claim 15, wherein the concentration of chlorodifluoromethane is not greater than about 10% (v/v).
17. A method according to claim 13, wherein the hydrofluorocarbon diluent is selected from the group consisting or fluorinated methanes, ethanes, propanes and butanes.
18. A method according to claim 13, wherein the concentration of methoxymagnesium methylcarbonate in the diluted composition is in the range of from about 0.1 to 2%
(w/v).
(w/v).
19. A method according to claim 13, wherein the concentration of methoxymagnesium methylcarbonate in the diluted composition is in the range of from about 0.5 to 1.5% (w/v).
20. A method according to claim 13, wherein the concentration of methanol in the diluted composition is less than about 5% (v/v).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2142195 CA2142195A1 (en) | 1995-02-08 | 1995-02-08 | Deacidification of cellulosic material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2142195 CA2142195A1 (en) | 1995-02-08 | 1995-02-08 | Deacidification of cellulosic material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2142195A1 true CA2142195A1 (en) | 1996-08-09 |
Family
ID=4155213
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2142195 Abandoned CA2142195A1 (en) | 1995-02-08 | 1995-02-08 | Deacidification of cellulosic material |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2142195A1 (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000008250A2 (en) * | 1998-07-31 | 2000-02-17 | Universitat Politecnica De Catalunya | Product for desacidification of cellulose material, production and utilization thereof |
| ES2151835A1 (en) * | 1998-07-31 | 2001-01-01 | Uni Politecnica De Catalunya U | Composition for de-acidifying cellulose materials and preserving cellulose-based articles e.g. contains carbonated magnesium di-n-propylate, n-propanol and fluorinated hydrocarbon solvent |
| ES2151836A1 (en) * | 1998-07-31 | 2001-01-01 | Univ Catalunya Politecnica | Composition for de-acidification of cellulose material |
| WO2003044277A2 (en) * | 2001-11-16 | 2003-05-30 | Honeywell International Inc. | Method of deacidifying cellulose-based materials |
| WO2005083176A1 (en) | 2004-02-27 | 2005-09-09 | Conservacion De Sustratos Celulosicos S.L. | Process for preservation of cellulosic materials |
| DE102008034100A1 (en) | 2007-09-18 | 2009-03-19 | Stu Fakulta Chemickej A Potravinárskej Technológie | Multifunctional device for modification of cellulose material such as printed- and paper products from books, magazines, manuscripts, maps and works of art on paper, technical drawings and other documents, comprises a drying chamber |
| EP2791417A4 (en) * | 2011-12-16 | 2015-08-26 | Honeywell Int Inc | Method of deacidifying cellulose based materials |
| WO2020228161A1 (en) * | 2019-05-13 | 2020-11-19 | 南京华鼎纳米技术研究院有限公司 | Anhydrous nano deacidification solution and preparation method therefor |
| CN113201968A (en) * | 2021-05-10 | 2021-08-03 | 杭州众材科技股份有限公司 | Fading restoration method suitable for paper yellowing after deacidification |
| CN116289318A (en) * | 2023-04-28 | 2023-06-23 | 常州大学 | Paper deacidification and reinforcement method |
-
1995
- 1995-02-08 CA CA 2142195 patent/CA2142195A1/en not_active Abandoned
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6743336B1 (en) * | 1998-07-31 | 2004-06-01 | Universitat Politecnica De Catalunya | Composition for de-acidification of cellulose material |
| WO2000008250A2 (en) * | 1998-07-31 | 2000-02-17 | Universitat Politecnica De Catalunya | Product for desacidification of cellulose material, production and utilization thereof |
| ES2151835A1 (en) * | 1998-07-31 | 2001-01-01 | Uni Politecnica De Catalunya U | Composition for de-acidifying cellulose materials and preserving cellulose-based articles e.g. contains carbonated magnesium di-n-propylate, n-propanol and fluorinated hydrocarbon solvent |
| ES2151836A1 (en) * | 1998-07-31 | 2001-01-01 | Univ Catalunya Politecnica | Composition for de-acidification of cellulose material |
| WO2000008250A3 (en) * | 1998-07-31 | 2000-05-18 | Univ Catalunya Politecnica | Product for desacidification of cellulose material, production and utilization thereof |
| WO2003044277A2 (en) * | 2001-11-16 | 2003-05-30 | Honeywell International Inc. | Method of deacidifying cellulose-based materials |
| WO2003044277A3 (en) * | 2001-11-16 | 2003-10-16 | Honeywell Int Inc | Method of deacidifying cellulose-based materials |
| WO2005083176A1 (en) | 2004-02-27 | 2005-09-09 | Conservacion De Sustratos Celulosicos S.L. | Process for preservation of cellulosic materials |
| DE102008034100A1 (en) | 2007-09-18 | 2009-03-19 | Stu Fakulta Chemickej A Potravinárskej Technológie | Multifunctional device for modification of cellulose material such as printed- and paper products from books, magazines, manuscripts, maps and works of art on paper, technical drawings and other documents, comprises a drying chamber |
| EP2791417A4 (en) * | 2011-12-16 | 2015-08-26 | Honeywell Int Inc | Method of deacidifying cellulose based materials |
| WO2020228161A1 (en) * | 2019-05-13 | 2020-11-19 | 南京华鼎纳米技术研究院有限公司 | Anhydrous nano deacidification solution and preparation method therefor |
| CN113201968A (en) * | 2021-05-10 | 2021-08-03 | 杭州众材科技股份有限公司 | Fading restoration method suitable for paper yellowing after deacidification |
| CN113201968B (en) * | 2021-05-10 | 2022-05-27 | 杭州众材科技股份有限公司 | Fading restoration method suitable for paper yellowing after deacidification |
| CN116289318A (en) * | 2023-04-28 | 2023-06-23 | 常州大学 | Paper deacidification and reinforcement method |
| CN116289318B (en) * | 2023-04-28 | 2024-03-26 | 常州大学 | Paper deacidification and reinforcement method |
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