Note: Descriptions are shown in the official language in which they were submitted.
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DEACIDIFICATION TREATMENT
OF PRINTED CE~LULOSIC MATERIALS
Related Application
This application is based on, and claims the benefit of, United States
Provisional Application Serial No. 60/071,103, filed January 9, 1998.
Field of the Invention
The present invention relates generally to compositions and methods
for deacidification treatment and preservation of printed cellulosic
materials, such
as books, manuscripts and other image and information bearing documents and
publications and works of art on paper, which may deteriorate or which may
have
become deteriorated through aging.
Background of the Invention
During the past 150 years, archives and libraries have struggled to
prevent the aging of paper, i. e. , yellowing and embrittlement of paper in
documents and books. Many treatments to avoid or stop this aging have been
proposed. The primary goals of these treatments are to either transform the
paper
into another, more stable medium or stabilize the paper against aging by
deacidificadon. Deacidification has advantages in its effectiveness for many
more
years, availability of stabilized materials for use, and lower unit treatment
costs.
Although previously known treatments reduce the rate that books
and documents are aging, all known methods have the potential to deface or
otherwise so harm significant portions of the collection so that the items are
rendered unsatisfactory for ordinary use. Furthermore, numerous problems and
environmental concerns exist with current treatment methods.
Moisture variation in anhydrous raw materials presents a significant
problem when using most known treatment methods. As the quantity of moisture
increases, either powder or gel precipitates will be formed, depending on
time,
reactivity, temperature and pressure conditions. These precipitates may
prevent
(poison), impede (slow) a manufacture or reaction rate and detrimentally
affect the
deacidification workability of solutions (clog paper substrates). The
precipitates
also may deposit on and deface books and documents and block or clog filters,
pipes, valves and other restricted passages in processing equipment. They may
also deposit thick coatings on walls of tanks and, depending on relative
densities,
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separate into top or bottom phase composition layers or even, in extreme
cases,
actually turn the treating solution (initially thinner than water) into an
immobile
gelatin-like gel.
Although produced, ultra-low moisture alcohol and aliphatic
S hydrocarbon solvents are not available commercially in standard containers,
e.g.,
in 5-gallon pails or 55-gallon dnilns. Industrial solvent manufacturers do not
deliver their solvents in an ultra-dry condition, i.e., below 15 or 25 ppm.
For
example, the maximum moisture content specification for a 55-gallon drum of
research grade "anhydrous" methanol from Fisher Scientific is 1,000 ppm.
Sub-micron (less than 0.2 microns) coal black particles are known
to precipitate in concentrates prepared for current treatment methods. The
particles may be introduced as trace heavy metal (iron, cobalt, copper, etc.)
impurities in the metals reacted with alcohols to produce alkoxide powders for
use
in treatment or by external conditions. These particles contaminate and
discolor
the treatment concentrate and must be removed before use in preservation.
Additionally, allowing the particles to agglomerate naturally then filtering
through
a 0.2 micron absolute membrane filter limits the concentration of treatment
concentrates that can be manufactured. For example, concentrations of organic
magnesium of up to only 25 percent by weight in methanol are a maximum.
The more alkaline pH values produced by organic magnesium
carbonate treatments may cause undesirable color changes. These treatments may
cause sensitive inks, pigments, and dyes to change color when the cellulosic
material is changed from a deteriorating acidic condition to a stable alkaline
condition.
The traditional CFC and HCFC solvent systems for organic metal
carbonate deacidification compositions tend to deface or damage some types of
inks and or cause structural book components to dissolve or soften. The more
sensitive inks soften, bleed, strike through, offset, and in some cases, even
glue
the leaves of pamphlets and books together into solid blocks. In addition, the
use
of chlorofluorocarbon solvents is generally prohibited by environmental
regulations.
Despite extensive efforts and the many solutions proposed for
stopping aging, a truly satisfactory method that extends the useful life of
cellulosic
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materials for hundreds of years has not been developed. No effective treatment
is
known that is acceptable for essentially all paper, inks, pigments, media, or
other
components of printed materials and is not hazardous to users.
Accordingly, it is a principal object of this invention to provide
improve deacidif ration compositions and methods for making them, for
preserving printed and written cellulosic materials, such as books, drawings,
maps, works of art, manuscripts and images.
It is an additional object of this invention to provide a method for
universally preserving these cellulosic materials bearing printing, writing,
drawings, or other recordings, with little or no impairment of inks, images,
bindings or other visual or structural features.
These and other objects of the invention will become apparent from
the following specification and accompanying drawings.
Summary of the Invention
Generally, in accordance with the present invention, a
deacidification composition for treating printed cellulosic materials is
provided. A
method of making the composition and a method of preparing components of the
composition also are provided. In an important aspect, the composition
comprises
a metal carbonate, an ultra-dry alcohol having a moisture content of less than
about 100 ppm and an ultra-dry solvent having a moisture content of less than
about 100 ppm, the solvent selected from the group consisting of alcohols,
aliphatic hydrocarbons, fluorocarbons and blends thereof, in amounts effective
for
treating and preserving printed cellulosic materials.
The deacidification treatment compositions of the present invention
are made by first treating alcohol, fluorocarbon, aromatic hydrocarbon or
aliphatic
hydrocarbon solvents with a molecular sieve or other desiccant to reduce the
moisture content below 100 ppm, to produce ultralow moisture solvents. An
organic metal alkoxide is blended with the ultralow moisture alcohol solvent
and
carbon dioxide to form an organic metal carbonate composition. Submicron-sized
magnetic impurities from the organic metal carbonate composition are removed
using magnetic filtration. Then the organic metal carbonate composition is
filtered
through a submicron filter to produce a deacidification treatment concentrate.
Finally, the deacidification treatment concentrate is blended with the
ultralow
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moisture solvent to provide a deacidification treatment solution having
relatively
inert solvation characteristics toward inks and structural components of
printed
cellulosic materials. This composition can be used in any known method of
treating printed cellulosic materials.
The ultra-dry solvents, which generally are available in standard
volume commercial containers, are made in a process comprising passing the
solvent through one or more drying columns. The solvent then is recirculated
to
the container, with re-circulation of the solvent through the container and
column
occurring for a period effective for reducing the moisture content to less
than
about 100 ppm to provide an ultra-dry solvent.
For purposes of the invention, "metal" or "metal agent" means
organic aluminum, magnesium, zinc or blends thereof. As used herein, "metal
alkoxide" means an organic aluminum alkoxide, magnesium alkoxide, zinc
alkoxide or blends thereof. As used herein, "metal carbonate" means an organic
aluminum carbonate, magnesium carbonate, zinc carbonate or blends thereof.
B_~ief Descrit~tion of the Drawinps_
FIGURE 1 is a flow diagram showing the method of making
compositions for treatment of printed cellulosic materials.
FIGURE 2 is an illustration of an apparatus for drying
deacidificadon solution solvents in accordance with the present invention.
FIGURE 3 is second embodiment of the apparatus of FIGURE 2.
Description of the Invention
The present invention is directed to a composition and method for
treating printed cellulosic materials to preserve the materials with little to
no
negative impact on inks, images, bindings or other features. The invention
also is
directed to methods of making the composition. More particularly, the
invention
is directed to compositions including organic aluminum, magnesium, and/or zinc
agents and ultra-dry solvents. The metal agents are blended with ultra-dry
alcohol
solvents with carbon dioxide to produce a non-aqueous deacidification
concentrate
composition. This concentrate composition is blended with ultra-dry solvents
to
produce a deacidification composition that can be used in sprays and solutions
to
protect books and dcxuments against aging.
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Method of Making the Deacidific~tion ~f'r»...~;.;"n
Referring to FIG. 1, which shows a single phase method of
manufacturing compositions of the present invention, metals 10 first are
blended
with an ultra-dry solvent 12 and carbon dioxide 14. In an important aspect,
the
metals used in the composition are organic aluminum, magnesium, zinc or
combinations thereof. The metal may be in the form of metal chips or a metal
alkoxide. Preferably, the solvent is an alcohol having 1 to 4 carbon atoms.
The
metal and solvent may be blended with stirring, shaking or other agitation as
necessary to provide a blend composition.
The metal, ultra-dry solvent and carbon dioxide react to provide a
deacidification agent 16 comprising metal carbonate. Magnets 18 are immersed
or
otherwise contacted with the deacidification agent for removal of sub-micron
particle impurities to provide a deacidification agent intermediate
composition 20.
The organic metal carbonate concentrates are refined and purified
by removing iron and associated heavy metals (e.g. copper and cobalt) present
in
the black magnetic particles. The submicron particles are removed by
attachment
to magnets, agglomeration and filtration through membrane filters.
Additionally,
allowing the agglomerates to settle and decanting the concentrate may be used,
as
well as any combination of these procedures, Magnetic filtration may occur in
single step (FIG. 1) or multiple step magnetic filtration (not shown).
The primary advantages of a single step procedure are speed of
removal and minimization of the contamination from moisture. Additionally, the
resulting concentrates are thinner and filter rapidly, subsequent blending,
mixing,
and transfer processes occur more readily, and costs of more processing and
losses
of concentrate composition during additional membrane filtration steps are
avoided.
Single step magnetic filtration emphasizes attracting particles to the
magnetic poles. Though higher concentrations are possible, typically 25.0,
37.5,
50.0, 62.5, or 75.0 percent concentrations in methanol are manufactured.
Concentrations in ethanol and isopropanol are typically 25.0 to 37.5 percent
by
weight. Magnets are immersed in the completed concentrate to agglomerate,
attract, and collect the particles.
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Teflon coated rod (ALNICO ~ magnets (1/2" by 6") designed for
use as spin bars in magnetic mixers may be used. Other magnets, including
electromagnets, magnetic grids, or magnetic particles which can readily be
separated from the solutions being treated, and flow-through magnetic
treatment
chambers, may be substituted for the spin bar magnets. The magnets may be
placed either in or-outside of the concentrate solution being magnetically
filtered.
Multiple step filtration involves repeating the complete single step
cycle at two or more pre-selected concentrations. For example, the organic
metal
carbonate concentrate is initially manufactured to 37.5 percent by weight
concentration, magnetically filtration treated, and membrane filtered through
a 0.2
micron filter. Then 25 percent more organic metal carbonate is blends with the
concentrate and the now 62.5 percent concentrate is again magnetically and
membrane filtered. Finally, 12.5 percent more organic metal carbonate is
blended
in, magnetically ark membrane filtered to produce a concentration level of
75.0
percent by weight in methanol.
The primary advantages of the mufti-step procedure are that stronger
concentrates exceeding 100 percent by weight can be produced, and the
quantities
of fme black particulates do not build up because they are removed as they are
formed. In addition, the potential for alcohols from mufti-step concentrates
to
deface books and documents by dissolving inks is essentially eliminated. The
quantity of free alcohol is very low, typically below 1 percent, and
preferably
below 0.5 percent by weight in the paper treating solutions.
Subsequent to the mag~tic treatment, the composition is filtered 22
using membrane filtration. Sub-micron pleated membrane (0.2 micron or smaller
pore size) filtration occurs after the desired concentration is attained,
typically at
the 37.5 and 62.5 percent concentrations, and after the solution has been
separated
from the magnets bearing the black magnetic particles. The 25.0 percent by
weight organic metal carbonate concentrations can be filtered through a 0.2-
micron
filter after overnight treatment, the 37.5 percent concentrate two days after
manufacture.
The concentrates may be subjected to moderate warming during
their manufacture. Additional amounts of ultra-dry solvents may be blended
with
the concentrates, as necessary for filtration. Filtration below the boiling
point of
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the alcohol being used is essential. The heat reduces the viscosity of the
concentrates, and improves magnetic filtration by reducing the required
propelling
pressure and increasing the rate of flow through membrane filters.
Membrane filters commercially available having pores larger than
0.2-microns do not completely remove the agglomerated particles and residual
fines from concentrate solutions. Ultra fine membrane filters, e.g., 0.1,
0.05, and
0.01-micron actual pore size (finest currently commercially available is 0.01-
microns) may be substituted for the 0.2 micron filters to produce more pure
filtrates.
Filtration provides a deacidificadon concentrate 24. The
deacidification concentrate then is blended with an ultra-dry solvent 26 to
provide
a deacidification com~sidon 28. In an important aspect, the solvent is an
alcohol
with 1 to 4 carbon atoms, an aliphatic hydrocarbon with 1 to 8 carbon atoms, a
fluorocarbon hydrocarbon, or mixtures thereof. The deacidificatinn
rn"r.Pnr~.~ta
and solvent may be blended with stirring, shaking or other agitation as
necessary
to provide a blend composition.
In an alternate embodiment, organic aluminum alkoxides, with or
without a carbon dioxide adduct and either alone or in combination with
organic
magnesium or zinc agents, are also useful deacidification agents. They may be
soluble directly in aliphatic and fluorocarbon solvents without an alcohol co-
solvent.
Ultra-Drv Solvents
The commercially available solvents that may be used in the present
invention include alcohols having 1 to 4 carbon atoms and aliphatic and
halogenated hydrocarbon solvents. Such solvents include methanol, ethanol,
isopropanol, isobutanol, propane, butanes, pentanes, isohexanes; heptanes,
difluoroethane (HFC-152a), and tetrafluoroethane (HFC-134a), HFC-32, HFE-
7100, HFE-7200, and HFC-10-43MEE.
Moisture which may be present in solvents presents a major
problem in preparing stable and non defacing organic metal carbonate
deacidification compositions, sprays, and solutions. Moisture, even under 50
or
100 ppm, may react with organic metal carbonates to form soluble hydrates or
gels that may thicken the solution or produce precipitates. In an important
aspect
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of the invention, 'the moisture level of alcohol solvents is no more than
about 100
ppm and in a very important aspect, no more than about 25-50 ppm. In an
important aspect of the invention, the moisture level of fluorocarbon and
aliphatic
solvents is no more than about 100 ppm and in a very important aspect, no more
than about 5-15 ppm.
In an important aspect, the composition of the invention comprises
fluorocarbon solvents. Preferably, the fluorocarbon solvent is HFC-134a. Mass
deacidification solutions containing HFC-134a solvent have almost no
detrimental
effect on all printing inks tested. Higher alkaline reserves are possible, if
desired,
because the metal carbonates, especially MMMC concentrates, have increased
solubility in HFC-134a. It is possible to achieve increased concentrate
solubility
using fluorocarbon solvents in the composition of the present invention, as
compared to chlorofluorocarbon solvents.
Previously soluble inks, such as purple mimeograph, photocopy,
and fast printing, offset inks that HCFC solvents such as HCFC-22 destroyed,
are
unaffected by treatment with HFC-134a or HFC-152a, with the same and far
higher levels of alcohol.
An almost total lack of ink solubility (when HFC-134a solvent is
substituted) indicates that alcohols have not caused inks to feather, offset,
or run,
etc. , as heretofore believed. (Rather the CFC and HCFC solvents most likely
caused such results.) As a result, tow unit-cost universal mass
deacidification
treatment is possible for preservation of archive and library general
collections.
The pre-selecting or exclusion of collections or individual books for
suitability for
deacidification, e.g., ink sensitivity, physical condition, or type of paper
is no
longer necessary.
Solvents in.the mass deacidification composition of the present
invention can be completely recovered and recycled indefinitely with minimal
benefaction requirements beyond adjustment for additional alcohol introduced
in
the make-up concentrate.
Deacidification Comvosition
The blending of powdered metal ethoxides (or metals) with an ultra-
dry alcohol (methanol, ethanol, isopropanol or isobutanol) with carbon dioxide
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occurs more rapidly. The concentrates of metal carbonates in methanol/ethanol
are much thinner, easier to process and filter, and more pure following
filtration.
Solids contents from about 25 to about 110 percent by weight of the
organic metal carbonate in methanol may readily be produced, from about 25 to
about 50 percent in ethanol, from about zero to about 40 percent in
isopropanol
and from about 0 to about 30 percent is isobutanol.
These ultra-dry, stronger concentrates of organic metal carbonates
form stable solutions in non-chlorinated fluorocarbon solvents such as
difluoroethane (HFC-152a) and tetrafluoroethane (HFC-134a). When first
blended, the concentrates may instantaneously precipitate out of solution on
contact
with HFC-i34a and slowly, over one to three or more days, gradually with
agitation (shaking and stirring) form a stable solution. The concentrates tend
to go
into solution in HFC-134a very rapidly when the HFC-134a is added in
increments, e.g., 1:1, 1:4, 1:8, etc.; whereas direct blending at a 1:8 ratio
produces a precipitate.
Varying the temperature of the final solution over a range from
about -10 to about 130°F and its concentration from less than about 1
to about 50
percent by weight had no affect on the stability of the solution in HFC-134a
solvent.
2p A prefen~ed deacidification composition for preserving paper
includes from about 0.1 to about 4.0 percent of organic metal carbonate, from
about 0.5 to about 10 percent by weight of ultra-dry alcohol and from about 86
to
about 99 by weight aliphatic or fluorocarbon solvent, each based upon the
weight
of the total composition. In an important aspect, from about 0.5 to about 3.0
percent metal carbonate of the deacidification composition is thoroughly
impregnated throughout the paper being protected against aging.
One deacidification composition comprises methoxy magnesium
methyl carbonate (MMMC) deacidification agent (which may include ethoxy
components) blended with HFC-134a at 0.5 to 4.0% by weight with a very low
level, less than 1 °Io by weight, of free methanol in the treatrnent
composition.
More methanol up to 10 percent may be used, if desired.
A second composition comprises from about 0.25 to about 5.0
percent by weight of isopropoxy magnesium isopropyl carbonate (PMPC) blended
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with HFC-134a solvent including from about 1.09b to about 10~ isopropanol.
The PMPC concentrate may include methyl and/or ethyl carbonate components.
Deacidification agents, MMMC and PMPC produce similar
deacidification treatment results with HFC-134a. The MMMC is preferred
because stronger concentrates may be prepared, the recovered solvents are
easier
to recycle, the treated books have a much lower odor level immediately after
treatment and hazards are reduced because less flammable material is involved.
Solutions of PMPC concentrate in aliphatic hydrocarbon solvents,
are extremely stable and combinations of solvents even dry to powder in open '
beakers in air without precipitation. Non-clogging aemsol sprays, solutions
for
brushing, and dipping paper may be prepared that do not produce white deposits
during treatment.
i_11,~~a-Drying Process
Ultra-drying in accordance with the present invention provides more
stable deacidification products during shipment, storage, and use, as well as
allows
manufacture of products not possible until now. The compositions of the
present
invention are further blended with ultra-dried solvents to produce non-aqueous
deacidification compositions for use as sprays and solutions for preserving
books
and documents. With ultra-drying of the solvents, the quality and purity of
starting solvents are established to a standard condition and can be used to
produce
finished products with predictable and reproducible properties.
Solvents, which are delivered in standard 55-gallon drums or similar
containers, typically having moisture levels of at least about 1000 ppm, may
be
inexpensively transformed into ultra-dry solvents using the apparatus of the
present
invention, as shown in FIG. 2. The drums 50 have two threaded openings (one 2"
LD. opening 51 and one 314" LD. opening 61). A dip tube 52 or similar piping
extends into the drum through the 2 in. LD. opening 51, preferably down to at
or
near the bottom of the drum.
One or more pumps 56, such as electro-magnetic or compressed air-
driven pumps, draw the solvent from the drum 50 up through the dip tube 52 and
through the inlet line 54 to one or more drying columns 58. The solvent is
passed
through the columns and returned back to the drum via a return line 60. The
return line extends through the 3/4" LD. opening 61. Inside the drum, the
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returned solvent is discharged via a tube 62. Preferably, the tube 62 is
angled or
otherwise configured to promote splashing and circulation as the solvent is
discharged in order to provide a mixing action.
The solvent is recirculated through the drum and column until the
moisture content is reduced to the desired level to provide an ultra-dry
solvent.
The solvent may be removed via a removal line 68 and transferr~ into smaller
containers, such as 6.5 gallon carboys, for subsequent use, if desired.
A source 64 of nitrogen gas, or equivalent, is connected to the
headspace in the drum to provide an inert amnosphere and a pressure head for
pumping. Valves 66 control the flow of gas into the drum.
Various valves 72 control the flow through the drum and columns.
Sight valves 74 are provided along the lines, as necessary. The preferred
materials for transfer hoses, connections, and valves are Teflon and stainless
steel.
For safety's sake, equipment and hoses must be grounded because the flowing
solvents can produce static electric charges that, if not discharged, may
cause
electric sparks.
UOP Molecular Sieve M/S 3A is effective in drying methanol,
ethanol, and isopropanol; HFC and aliphatic hydrocarbon solvents. UOP
Molecular Sieve M/S 4A, XH-7, and XH-9 may be used to dry and also remove
alcohol from HFC, and aliphatic hydrocarbon solvents. Equivalent desiccants
from other manufacturers, e.g. MS-592 and MS-594 from Grace, also may be
used.
Alternative drying products include highly desiccated silica gel and
desiccant aluminum oxide and silicate powders. All of these desiccants may be
used in alternate forms; e.g., molded core dryers prepared to fit into a
specific
steel shell. Fluorocarbon solvents, such as HFC-134a, may cause some of these
desiccants, e.g., UOP M/S 3A, to evolve a fine, white powder that can be
removed during filtration.
In a second embodiment, as shown in FIG. 3, both lines extend
through the same opening of the drum. For ease of reading, features of the
first
embodiment will be given the same reference numerals in FIG. 3 as used above.
The inlet line 54 and return line 60 both extend through the 2" LD. opening
51.
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The removal line 80 extends from the return line 60 above the drum. The
remaining features are as shown and described above for FIG. 2.
Deacidification Treatment
The deacidification compositions of the present invention may be
used in processes for treating aad preserving printed cellulosic materials.
The
compositions can be used to prepare aerosols, solutions or other forms, as
desired.
The deacidification compositions may be used with any known
treatment process. Generally, a process for mass deacidification using the
composition in a solution form includes first thoroughly drying under vacuum
the
materials to be treated. The materials then are contacted with the composition
for
a period of time effective for thoroughly wetting the materials. During
contact,
the composition may be impregnated under pressure into the materials. After
the
solution is removed from the materials, any solution remaining in the
materials is
vaporized for recovery and recycling to vacuum conditions. In this process, it
is
possible to recover at least about 93-95 % of the deacidificadon solution,
which can
be re-used in the process.
The following examples illustrate compositions and methods for
carrying out the invention. These examples should be understood to be
illustrative
of, but not limiting upon, the scope of the invention which is defined in the
appended claims.
~lltra-Drv Methanol
Anhydrous methanol delivered in a 200 liter drum is treated using
the apparatus of FIG. 1. The methanol initially contains 900 ppm water. The
drying columns are 24" high columns filled with UOP molecular sieve desiccant
M/S 3A., connected by 1/4" LD. Circulation through Column 1 and subsequently
Column 2 is continued for 36 hours consecutively in each drying column. The
final water content of the methanol after treatment is 25 ppm.
Example 2
Ultra-Drv Isonro~anol
A 55-gallon drum of isopropanol is ultra-dried as described in
Example 1. The moisture content of the isopropanol is reduced from 800 ppm at
beginning to 20 ppm at end.
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x le 3
jJltra-Drv Isouentane
Isopentane solvent is treated in a 55 gallon stainless steel drum with
the apparatus of FIG. 3. The moisture content of the isopentanes solvent is
reduced from 1,000 ppm at lxginning to 15 ppm at end.
E~ple 4
MMMC Concentrate & Single Stev Magnetic Filtration
On Day 1, four kilograms of granulated magnesium ethoxide and
carbon dioxide gas are added to two 6.5-gallon flint glass carboy containing
14
liters of ultra-dry methanol prepared in Example 1. The components are reacted
to produce a coal black, organic magnesium carbonate solution of MMMC in
methanol. The magnesium ethoxide is kept in suspension in the methanol using
an
electromagnetic mixer; the carbon dioxide gas is added at ambient pressure at
a
rate of 5 cfm/hr. through a gas diffusion stone.
On Day 2, two kilograms more magnesium ethoxide are reacted to
produce a 37.5 percent concentrate. On completion of the reaction, four wired
together, magnetic stirring rods (1~2" by 6" each), are immersed in one of the
two
concentrates to provide magnetic filtration. The carboy and contents of both
concentrates are maintained at 100°F.
On Day 3, the four magus are removed and the mother liquor,
now a translucent gray color, is filtered using 15 psig nitrogen gas pressure
through a 20" long, 0.2-micron membrane filter in fifteen minutes to produce a
water clear, light straw colored concentrate solution of filtrate. The poles
of the
magnets were coated with a fine black powder 1/16" to 1/8" thick when removed
from the concentrate.
On Day 3, the mother liquor without magnetic filtration in the
second concentrate solution is still coal black. It has a hazy, blackish gray
amber
color after being filtered through a 0.2-micron filter. Most of the black
particles
remain so small they pass through the 0.2-micron pores.
F~am~le 5
PMPC Concentrate & Sin~,~le Step filtration
On Day 1, three kilograms of granulated magnesium ethoxide and carbon
dioxide gas are added to two 6.5-gallon flint glass carboys containing 15
liters of
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ultra-dry isopropanol prepared in Example 2, and reacted as described in
Example
4 to form isopropoxy magnesium isopropyl carbonate (PMPC). On completion of
the reaction, magnets are inserted in one carboy to provide magnetic
filtering, and
the concentrates are maintained at 110°F as described in Example 4.
On day 5, the magnets are removed and the mother liquor, now a blackish
gray-brown color, is filtered in 25 minutes to a clear amber concentrate
filtrate.
Without magnetic filtration, the mother liquor remains black and, after
filtering through a 0.2-micron filter, is a blackish charcoal gray color.
Without magnetic filtration and concentrate heating, the PMPC concentrate
needs weeks of natural aging for agglomeration before it can be filtered to a
dark
amber concentrate.
Example 6
~Vlethoxv Zinc Methyl Carbonate Concentrate
On Day 1, 1.5 kilograms of fine zinc chips with a catalyst is added to a
mag~tically stirred, 6.5-gallon flint glass carboy containing 14 liters of
ultra-dry
methanol prepared in Example 1, and reacted at 100°F to form zinc
methoxide.
Carbon dioxide is added as described in Example 4 to form methoxy zinc methyl
carbonate (MZMC). On completion of the reactions, magnets are inserted to
provide magnetic filtering, and the concentrates are maintained at
100°F as
described in Example 4.
On Day 2, the magnets are removed and the mother liquor, now a
translucent gray color, is filtered using 10 psig pressure through a 0.2
micron
membrane filter in fifteen minutes to produce a water clear, near white
concentrate
filtrate.
~,s~pronoxv Zinc Isopropyl Carbonate Concentrate
On Day 1, one kilogram of fine zinc chips with a catalyst is added to a
magnetically stirred, 6.5-gallon flint glass carboy containing 15 liters of
ultra-dry
Isopropanol prepared in Example 2, and reacted at 110°F to form
zinc
isopropoxide. Carbon dioxide is added as described in Example 4 to form
isopropoxy zinc isopropyl carbonate (PZPC). On completion of the reactions,
magnets and inserted to provide magnetic filtering, and the concentrates are
maintains at 110°F as described in Example 4.
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WO 99/35?,0'/
On Day 2, the magnets are removed and the mother liquor, now a
translucent gray color, is filtered using 10 psig pressure through a 0.2
micron
membrane filter in fifteen minutes to produce a water clear, near white
concentrate
filtrate.
Examine 8
~ylaanetic Multi-S~ Filtration
On Days 1, 2, and 3, a 37.5 percent concentrate of MMMC is prepared
and magneticanny filtered as described in Example 5. Also on Day 3, four
kilograms more granulated magnesium ethoxide and carbon dioxide gas are
reacted
with the fintrate to produce a 62.5 percent, coal black MMMC concentrate.
Again
four magnets are inserted to provide magnetic filtration, and the concentrate
is
maintained at 110° F.
On Day 5, the four magnets are removed, cleaned, dried, and replaced.
Their poles are coated with a fine black powder 1/16" to 1/8" thick when
removed
from the concentrate. The four cleaned magnets are reinserted on Day 5, and
contents kept at 110°F. On Day 7, the magnets (coated 1/16" to 1/8"
thick) are
again removed; and the 62.5 percent concentrate is filtered for the first time
with a
psig. Nitrogen gas pressure through a 0.2-micron filter in 45 minutes. The
concentrate filtrate is a light amber color that dries to a snow white powder.
20 Exam a
M_ ass De--acidification - PMPC
Forty-five pounds PMPC concentrate from Example 5 are added,
under nitrogen gas, to a 16-gallon stainless steel tank, thinn~i with 45
pounds of
HFC-134a, and mixed for 30 minutes on a seesaw shaker to produce a 1:1
PMPC/HFC-134a ratio. The tank is pressurized to 160 psig with nitrogen gas in
preparation for manufacture of a liquefied gas mass deacidification sonution.
Seventy pounds HFC-134, nine pounds of 50/50 PMPC HFC-134a
concentrate, and 40.5 pounds HFC-134a are transferred into a vacuum dried 12.5
gallon steel shipping cylinder, which is inverted and mixed for 30 minutes on
a
seesaw shaker.
Books and documents representing successfully treated and damaged
or destroyed materials in CFC and HCFC solvent mass deacidification solutions
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WO 99I35Z07
are selected for treatment in the Wei T'o Liquified Gas Mass Deacidification
System.
The PMPC solution, initially hazy from fine bubbles, clears to give
a crystal clear, water white solution in the sight glasses with no signs of
discoloration, precipitation, or phase separation before and after use, as
compared
to HCFC-22 solution and previous CFC containing solutions which show a slight
yellowing after use.
All materials treated with the PMPC/HFC-134a solution show fewer
signs of treatment change than occurs in books treated with the HCFC-22
formulation. Books regularly treated in HCFC-22 have equal or superior
appearance after treatment with the PMPC/HFC-134a solution. Most books, inks,
and other components normally identified as untreatable in CFCs and HCFCs
exhibit no, or very few, changes from treatment. These materials included fast
printing inks used for ephemeral government reports and pamphlets, and purple
mimeograph inks. No covers or illustrations (including heavily black inked
ones)
show unsightly bloom or white iridescent deposits.
As compared to treatment with HCFC-22 solutions, the books and
bindings were straighter and text blocks less distorted aml expanded. All of
the
protective plastic films on paperback book covers were less affected. The
binding
adhesives in almost perfect bound and paperback books were unaffected. No
bindings loosened or came completely apart.
S le pH Control' pH Treated' Alkaline Reserve
treated
~k A3 3.78 t 0.00 9.04 t 0.02 0.65 t 0.03
~k g 5.23 t 0.03 9.05 t 0.01 0.71 t 0.02
2$ Book C, Paper 6.24 10.05 8.71 t 0.02 0.96 t 0.04
#Ss
Book C, Paper 5.23 t 0.02 9.69 t 0.00 0.91 t 0.01
#66
' CPPA Standard G.25P
ASTM Standard D 3290, 11.4 (modified by using pH meter to determine end point)
' Depamnent of Mines and Technical Surveys
' Performance Measurement in Federal Libraries
Test Book (National Library of Canada), Paper #5, "Alum Rosin"
Test Book (National Library of Canada), Paper #6, "New Newsprint"
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Example 10
M_ ass Deacidification - MMMC
MMMC concentrate (28.5-pounds) from Example 4 is diluted with
57-pounds of HFC-134a in a 16-gallon tank and mixed for 15 minutes on a seesaw
shaker. Fifty-seven more pounds of HFC-134a are added, and mixed again for 15
minutes to form a 1:5 ratio solution.
The actual mass deacidification solution is prepared in clean,
vacuum dried 12.5-gallon steel cylinders in four weighing and two mixing
steps:
(1) 26 lbs of HFC-134a Recovered Solvent; (2) 23.75 lbs. MMMC at 1:5 Ratio;
(3) 25 lbs. HFC-134a Recovered Solvent; (3a) Mix on Seesaw Shaker for 10
minutes; (4) 50.25 lbs. HFC-134a Recovered Solvent; (4a) Mix on Seesaw Shaker
for 15 minutes.
The results equal or exceed the quality of treatments from all
previous treatments including the PMPC/HFC-134a treatment of Example 9.
Overall, the MMMC/HFC-134a solution treatment is preferred because it has less
residual odor, is easier to manufacture and filter, is more readily recovered
and
recycled, and its stronger concentrates produce higher alkaline reserves.
~~amnle 11
zinc Mass De~cidifi tion - MZMC
MZMC concentrate (28.5-pounds) from Example 6 is diluted with
57-pounds of HFC-134a in a 16-gallon tank and mixed for 15 minutes on a seesaw
shaker. Fifty-seven more pounds of HFC-134a are added, and mixed again for 15
minutes to form a 1:5 ratio solution. The actual mass deacidification solution
is
prepared in clean, vacuum dried I2.5-gallon steel cylinders in four weighing
and
two mixing steps: (1) 26 lbs. HFC-134a Recovered Solvent; (2) 23.75 lbs. MZMC
1:5 Ratio; (3) 25 lbs. HFC-134a Recovered Solvent; (3a) Mix on Seesaw Shaker
for 10 minutes; (4) 50.25 lbs. HFC-134a Recovered Solvent; (4a) Mix on Seesaw
Shaker for 15 minutes.
As the pH of deacidified paper after deacidification remains near
7.5, sensitive yellow, blue, green, and red colorants used in works of art do
not
change color.
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~~ple 12
PCTNS99/00434
_Soft Spray - P~
Four pounds of the 1:1 ratio PMPC/HFC-134a concentrate prepared
in Example 9 are transferred into a clean, vacuum dried 4.5-gallon steel
cylinder
and used in situ to prepare a new formulation of Wei T'o Soft Spray (U.S.
Patent
4,860,685, incorporated in its entirety herein by reference). Four weighing
addition steps are involved: (1) 20.0 lbs. Ultra-dry HCFC-141b. (Example 4);
(2)
4.0 lbs. PMPCIHFC-134a (1:1 ratio) (Example 7); (3) 15.0 lbs. Ultra-dry HCFC-
141b (Example 4); (4) 2.0 lbs. HFC-134a; (4a) Nitrogen gas at 80 psig.; (4b)
Mixing on Seesaw Shaker for 10 min.
Fxat~t ,Dle 13
Soft Snrav - Hevtane & Propane
A 4.5-gallon cylinder of Soft Spray is prepared as is described in
Example 11 except flammable solvents are substituted for HCFC-141B and HFC-
134a: (1) 1.00 lbs. Ultra-Dry Isopropanol (Example 3); (2) 10.00 lbs. Ultra-
dry
Low aromatic heptanes (Example 4); (3) 2.125 lbs. PMPC Concentrate (Example
7); (4) 10.00 lbs. Ultra-dry Low aromatic heptanes (Example 4); (5) 3.00 lbs.
Propane; (5a) Nitrogen gas at 80 psig.; (Sb) Mixing on Seesaw Shaker for 10
min.
Soft Sgrav - Pen~ta_ne & HFC-152a
A 4.5-gallon cylinder of Soft Spray is prepared as is described in
Example 12 except flammable solvents Pentane and HFC-152a are substituted for
HCFC-141B and HFC-134a respectively. The weighing and preparation sequence
is: (1) 1.00 lb. Ultra-Dry Isopmpanol (Example 3); (2) 8.50 lbs. Ultra-dry
Isopentanes (Example 4); (3) 2.125 lbs. PMPC Concentrate (Example 7); (4) 8.50
lbs. Ultra-dry Isopentanes (Example 4); (5) 3.00 lbs. HFC-152a; (5a) Nitrogen
gas
at 80 psig.; (5b) Mixing on Seesaw Shaker for 10 min.
Example 15
Aer 1 - 3 71 -n na a bu & F - 34a
A number of aerosol spray cans are filled with a non-flammable
aerosol spray as follows. A non-pressurized formulation of solvents and
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concentrate is loaded into a stainless steel tank under nitrogen gas in the
following
order:
(1) Ultra-dry 3M HFE-7100 40.0 lbs. (Example 4)
(2) PMPC Concentrate 8.0 lbs. (Example 7)
(3) Ultra-dry 3M HFE-7100 40.0 lbs. (Example 4)
The tank is closed and mixed, upside down, on a seesaw shaker for
one hours, left stand over night and mixed again for one hour. The formulation
is
pressurized with ten psig of nitrogen gas, and is loaded 650 grams per unit
into
welded steel, epoxy-phenolic lined pint aerosol cans which are crimped closed
with an all-steel, except neoprene gaskets, aerosol male tilt valve. The cans
are
pressurized with 125 grams of HFC-134a pressurized to 110 psig with nitrogen
gas through the valve using a pressure burette, and subsequently mixed by
vigorous manual shaking.
Exa~~le 16
Aerosol MMM HFE-7100 & HFC-152a
A number of aerosol spray cans are filled with a non flammable
aerosol spray as in Example 15 except the HFC-134a propellant is replaced with
HFC-152a on a molecular weight basis. The cans are pressurized with 100 grams
of HC-152a as in Example 15.
Example 17
~eros~l - Aliv tic Sglvents & Prod
A number of aerosol spray cans are filled with a flammable aerosol
spray. The following non-pressurized formulation of solvents and concentrate
is
weighed (directly from their ultra-drying drums or filtrate container) into a
16-
gallon stainless steel mixing tank under nitrogen gas in the following order:
(1) Ultra-dry Low aromatic heptanes 20 lbs. (Example 4)
(2) Ultra-dry Isopentanes 20 lbs. (Example 4)
(3) PMPC concentrate 9 lbs. (Example 3)
(4) Ultra-Dry Isohexanes b0 lbs. (Example 4)
The tank is closed and mixed upside down on a seesaw shaker for
two hours, and then pressurized with 10-psig nitrogen gas. Welded, tin-free
steel,
aerosol cans, lined with an epoxy-phenolic coating, are filled 350 gms/can,
and
crimped shut with an all-steel, except neoprene gaskets, tilt-type, male,
aerosol
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valve. The cans are pressurized through the valve with 65 grams of propane
using
a pressure burette transferred with 120-psig nitrogen gas pressure and mixed
manually by vigorous hand shaknng.
Example 18
Aerosol - Pentane & HFC-152a
A number of aerosol spray cans are filled with a flammable aerosol
spray as described in Example 17 according to the following formula:
( 1 ) Ultra-dry Isopentanes 40 lbs. (Example 4)
(2) PMPC concentrate 9 lbs. (Example 3)
(3) Ultra-Dry Isopentanes 40 lbs. (Example 4)
After mixing, the tank is pressurized with 10-psig nitrogen gas, and
the aerosol cans are filled 300 gms/can, and crimped shut with a
metal/plastic,
female aerosol valve. The cans are pressurized through the valve with 75 grams
of HFC-152a using a pressure burette pressurized with 100-psig nitrogen gas.
Examine 19
Zinc Aerosol - Pentane & HFC-152a
A number of aerosol spray cans are filled with a flammable aerosol
spray as described in Example 17 according to the following formula:
(1) Ultra-dry Isopentanes 40 lbs. (Example 4)
(2) PZPC concentrate 9 lbs. (Example 3)
(3) Ultra-Dry Isopentanes 40 lbs. (Example 4)
After mixing, the tank .is pressurized with 10-psig nitrogen gas, and
the aerosol cans are filled 300 gms/can, and crimped shut with a
metal/plastic,
female aerosol valve. The cans are pressurized through the valve with 75 grams
of HFC-152a using a pressure burette pressurized with 100-psig nitrogen gas.
As the pH of deacidified paper remains gar 7.0, sensitive yellow,
blue, green, and red colorants used in works of art do not change color.
Example 20
Aerosol - Barrier & Desiccant Protection
Aerosol spray cans prepared according to the above examples may
malfu~tion and clog as a consequence of inadvertent moisture contamination
following manufacture and delivery. This malfunction can be avoiaea uy
preventing the moisture in air from contacting the valves as follows using a
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moisture barrier film (e.g., polyvinylidene chloride film (Dow Chemical Saran
Wrap 8)) and desiccant (e.g., United Technologies silica gel or UOP M/S 3A).
(1) Cover valve opening with 0.46 mil barrier film and press into place.
(2) Place a 3-gram bag of desiccant on top of film to fit under cap.
(3) Cover desiccant bag with 0.46 barrier film that extends over side of
aerosol can and press into place. Additional or thicker films may be
used.
(4) Snap tight fitting plastic in place sealing barrier film to can.
(5) Remove the excess barrier film extending from can.
(6) Replace the film and refresh (re-dry) the desiccant after partial
usage to extend protective storage.
Examg~e 21
Solution - Pentanes & Henta~s
A number of glass quart bottles are filled with a flammable deacidification
solution as follows. A non-pressurized formulation of solvent and concentrate
is
loaded into a stainless steel tank under nitrogen gas in the following order:
(1) Ultra-dry Low aromatic heptanes 40.0 lbs. (Example 4)
(2) PMPC concentrate 9.0 lbs. (Example 3)
(3) Ultra-dry Isopentanes 40.0 lbs. (Example 4)
The tank is closed and mixed, upside down, on a seesaw shaker for two
hours. The formulation is pressurized with ten psig of nitrogen gas, and
transferred using Teflon tubing, 850 grams per unit, into glass quart bottles.
The bottles are closed with a conventional plastic threaded cap whose liner
(gasket) is composed of paperboard covered with a sealing composite composed
of
alumi~m foil covered with a Mylar (polyester terephthalate) plastic film or
equivalent barrier material to prevent the inward migration of moisture from
ambient air. The bottles are shaken subsequently vigorously manually to insure
mixing. The resulting solution may be applied by dipping, bnishing, spraying
or
other technique to thoroughly wet paper objects.
This solution can also be prepared in steel cylinders for spray application
with nitrogen gas pressure, steel, phenolic-epoxy lined, or stainless steel
cans, and
other sizes of glass bottles, etc. with appropriate barrier closures as
desired. Up
to 10 percent, typically 3 to 5 percent, by weight of co-solvents bromopropane
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and/or diethylene chloride may be added to improve solubility of PMPC
co~entrate if desired.
The pmportions of the aliphatic solvents may be varied to customize the
rate of drying from and treatment penetration into paper, and indirectly
control the
evolution of solvent vapors into workroom air.
Example 22
The composition of the two papers tested is as follows:
Paper A: an acid fine paper made of 50°r6 hardwood bleached kraft,
50°k
softwood bleached kraft (post-industrial), 4 ~6 filler (clay), alum-
rosin sizing and starch
Paper B: an acid newsprint made of 100% thermomechanical pulp (TMP)
with alum-rosin sizing
The samples were conditioned at 23 ° C . and 50 '~ RH prior to testing
according to
CPPA standard A.4.
Table 1: Testing Data
SampleAging Number of Cold Alkaline
Time double Extraction' reserve'
(Days)' folds (at (PH) (
500 g)Z
A1 0 1186 t 98 5.24 t 0.04 -_
50 39 t 6 4.74 t 0.01 ---
A2 0 1499 t 171 9.47 t 0.10 1.65 t 0.58
50 1199 t 110 10.19 t 0.101.79 t 0.17
A3 0 1294 t 133 9.68 t 0.03 1.94 t 0.04
50 849 f 129 10.12 t 0~ 1.74 t 0.14
A4 0 1467 t 159 10.28 t 0.025.75 t 0.23
50 956 t 127 10.57 t 0.025.38 t 0.18
A5 0 1320 t 1~ 9.80 t 0.06 1.98 f 0.16
50 853 t 87 10.13 t 0.~ 1.64 t 0.12
A6 0 1467 t 151 9.67 t 0.08 2.12 t 0.17
50 865 t 122 10.34 t 0.102.15 t 0.21
A7 0 1131 t 121 9.74 t 0.20 2.69 t 0.22
50 813 t 98 10.42 t 0.072.55 t 0.30
A8 0 1121 t 152 9.78 t 0.01 2.33 t 0.11
50 612 t 72 10.20 t 0.071.95 t 0.43
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B 1 0 1020 t 108 5.51 t 0.08--
50 115 t 12 4.82 t 0.08---
B2 0 929 t 87 10.03 t 1.71 t 0.46
0.11
50 690 t 70 9.30 t 0.920.44 t 0.30
B3 0 1065 t 91 10.29 t 2.98 t 0.39
0.04
50 690 t 77 10.41 t 1.79 t 0.49
0.09
B4 0 1059 t 125 10.51 t 5.05 ~ 0.57
0.04
$ 50 422 t 60 10.67 t 5.98 t 0.40
0.07
B5 0 819 t 141 10.29 1Ø092.59 t 0.10
50 713 f 128 10.41 t 2.11 t 0.26
0.08
B6 0 1037 t 139 10.31 t 3.53 t 0.32
0.13
50 692 t 109 10.49 t 2.38 t 0.47
0.10
B7 0 1111 t 143 10.38 t 4.18 t 1.70
0.10
50 627 t 71 10.54 t 3.10 t 0.15
0.01
B8 0 932 t 101 10.32 t 3.27 t 0.17
0.02
50 501 t ~ 10.50 t 2.52 t 0.40
0.07
Al, B1
- Control
A2, B2 - Mass Deacidification - MMMC
A3, B3 - Aerosol - 3M HFE-7100 and
PMPC/HFC-152a
A4, B4 - Aerosol - Isopentanes and
PMPC/HFC-152a
A5, BS - Aerosol - Low aromatic heptanes
and PMP/HFC-152a
A6, B6 - Solution - 3M HFE-7100 and
PMPC
A7, B7 - Solution - Isopentanes and
PMPC
A8, 88 - Solution - Low aromatic heptanes
and PMPC
Paper and board - accele~at~ aging. Part 3: Moist heat treatment at
80°C and 6596
relative humidity. ISO Standard 5630/3. 1986
z Foldiag endurance and paper (M1T tester). Official Test Method T 511 om-88.
Technical
Association of the Pulp and Paper Industry Test Methods. 1992-1993.
Hydrogen ion concentration (pH) of paper extracts (cold extraction method).
Official Test
Method T 509 om-88. Technical Association of the Pulp and Paper Industry Test
Methods. 1992-1993.
° Standard test method for the determination of calcium carbonate
content of paper. ASTM
Standard D4988-89. Annual Book of ASTM Standards 15.09 (1990).
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