Richard D. Smith

Wei T’o® Associates, Inc., Matteson, IL

Rev. October 15, 1998

1. Summary

This report summarizes the background and development of the Good News® Family of Wei T’o deacidification sprays and solutions. The first two Family members were non flammable liquefied gas mass deacidification solutions using HFC solvents to dissolve organic magnesium carbonates. That research led to eight new aerosol sprays and solutions and Soft Sprays that are dissolved in aliphatic hydrocarbon solvents propelled with a flammable HFC. All of these products are “Green” with minimal environmental impact, including no affect on the Ozone Layer. The possibility of book, document, and image defacement is very low, e.g., only one ink has feathered, offset, transferred, blocked, or struck through, etc. during the first ten months of mass deacidification use.

An accelerated aging study on the efficacy of six aerosol sprays, solutions, Soft Spray, and one mass liquefied gas deacidification solution conducted at the Canadian Conservation Institute (CCI) was completed in July 1998, and will be published promptly. Preliminary results show the properties of these new products are superior to traditional Wei T’o products, and represent a major breakthrough in conservation and deacidification technology.

2. Deacidification Background

The goal of the Wei T’o Mass Deacidification Process is to provide the capability for mass deacidification to start at one end of general archive or library collection and go book by book to the other end with no or negligible pre-selection or damage. A deacidification process, to achieve this goal, should:

  1. Be effective and stabilize books and documents against aging for prolonged periods of time, i.e., several hundred years.
  2. Be capable of treating all types of inks, paper, and book components, including thick books and boxes full of archival records that contain coated or super calendered papers, and tattered, yellowed, and embrittled pages.
  3. Be safe for persons operating the process, handling, and reading the books after their treatment. Introduce no harmful, bad smelling odors, or hazardous gases or materials into books and libraries.
  4. Be compatible with and function synergistically with other preservation treatments and storage conditions.
  5. Be cost affordable for archives and libraries.


Several respected requirements for a mass deacidification process need re-consideration. Their continued application may produce negative effects, e.g., reduce the number of books that can be preserved and lower the quality of the deacidification treatment.

  1. Deposit a minimum alkaline reserve of 1.5 percent by weight of calcium carbonate or equivalent deacidification agent. By comparison, accepted aqueous deacidification processes impregnate a much smaller amount. This practice raises the question whether effectiveness, not the quantity, of an alkaline reserve is the crucial factor for long term preservation.
  2. Have no affect on microfilms, phonograph records, audiotapes, or CD, computer or optical discs, etc. that may be placed in books or archival boxes. Deposition of an alkaline residue onto a microfilm, phonograph record, audiotape, or computer or optical disc, etc. can to lead to its subsequent malfunction.
  3. Contain no alcohol, particularly methanol, because alcohols cause inks to run, feather, offset, bleed, strike through, or block gluing pages together, etc. Though not recognized until recently, the methanol in Wei T’o products has not caused inks to be unstable for over 15 years.
  4. Require pre-selection to identify and remove books with components that might be damaged by treatment. Since very few items are affected by present day treatments, the savings from accepting a slight chance of damage but no loss of information may be traded for preservation of larger numbers of books and documents. In any event, unique or especially valuable items should be identified and transferred to Special Collections.
  5. On one hand, vacuum drying of books is questioned based on applying space technology and the alleged costs of test and pilot plant deacidification operations. On the other hand, the value of trouble free production and quality of treatment benefits from vacuum drying, ability to treat fragile materials, and complete deacidification throughout closed books containing all types of paper are not considered. The cost-benefit effect from application of vacuum techniques used to achieve low production costs and the high quality of every day products such as freeze dried coffee, and foods, drugs, and other essential medical products apparently also has not been considered by the critics.
  6. Contain no components having a negative environmental or other effect. All processes have undesirable side effects. More important than side effects is whether the benefits received from treatment are greater than its risks and damages. In 1996, the Wei T’o Mass Deacidification Process in Canada went back to its original 1970s operating procedure. Emissions of HCFC’s were reduced to approximately 8 percent. Since 1997, only HFC solvents that have no affect on the Ozone Layer are used. Future Wei T’o system installations will produce neither emissions nor significant environmental impact. Essentially 100 percent of all solvents will be recovered and recycled. Present recovery (2000) exceeds 97 percent.

3. Development Process

The Wei T’o approach was rigorously evaluated between April 1, 1992, and mid July, 1995, when the National Archives of Canada and the National Library of Canada, Ottawa, Ontario, operated their Wei T’o Mass Deacidification System 24 hours per day, five days per week. Wei T’o Canada Inc. was established in a suburb of Toronto (250 miles from Ottawa) to manufacture mass deacidification solutions and recycle recovered solvents.

The technical and administrative people involved included Real Couture, Chief, Mass Deacidification System, who is certified as an operator of refrigeration and air conditioning equipment, Neal Armstrong, York Corporation, responsible for maintenance of certain equipment, Dick Smith, Wei T’o Canada Inc., plus administrative personnel at the National Archives and National Library. Suppliers provided additional technical support, particularly Dupont Canada Inc. Operating personnel were high school graduates who were trained on the job at the National Archives or Wei T’o.

At the beginning, Wei T’o Canada had no facilities and no employees, only Dr. Smith. The National Archives and National Library had fully tested operational equipment, plus Mr. Couture, his 1 assistant, and a very capable administrative staff. The operating personnel quickly grew from a two person, one shift operation, into 20 some personnel operating 24 hours per day, and drawing critical supplies and services from its vendor network in Europe, Asia, United States, and Canada.

The scheduling and operational problems that this team overcame included:

  1. Within two weeks from approval of funding in late March, deacidification solutions were being delivered on schedule, acidic books needing stabilization treatment were available, and operators were hired and trained. The second shift commenced mass deacidification treatment about April 5, the 3rd shift and the five-day full 24-hour schedule before May 1, 1992.
  2. Meeting the business and regulatory standards to establish and staff manufacturing and solvent recycling facilities in Canada, obtain and install the equipment, and commence delivery of recycled solvent containing deacidification solutions occurred by mid-May.
  3. Locating, installing, and operating replacement equipment when the originally installed components broke down, malfunctioned, or became unusable without affecting production schedules.
  4. Establishing new suppliers for solvents when original or prior sources became unable to supply.
  5. Developing technology and equipment for producing standard quality deacidification solutions using industrial solvents and materials whose properties varied from their promised specifications.
  6. Recovering and recycling deacidification products damaged by freezing enroute from Toronto to Ottawa; over 10,000 pounds of solvents were purified and recycled.
  7. Meeting strict Canadian environmental regulations and cleaning the Wei T’o manufacturing plant after a transfer pump malfunctioned and spilled 550 lb. of recovered solvent, etc. which was partially vaporized into hydrochloric and hydrofluoric acids.

About everything bad that might have happened actually did happen precisely as Murphy’s Law predicts. Everybody cooperated closely together to overcome all of the operational challenges when they occurred. The group truly demonstrated that the Wei T’o process and its deacidification equipment functioned properly, and thoroughly deacidified books and documents. A random sample of books and documents treated during this period in the Wei T’o system were compared to books and documents treated at the AKZO, DEZ, and FMC Lithco systems by Canadian Conservation Institute. The results have been published. Each system was found to have advantages and disadvantages. My unofficial understanding is the Wei T’o System produced the best results overall.

On April 1, 1995, a federal financial crisis in Canada caused the budget of the National Library to be slashed 30 percent across the board. The mass deacidification project at the National Archives was cut back, and its staff reduced to one person in July 1995. Wei T’o Canada closed in mid July, and its functions and services were transferred to Wei T’o Associates.

Since 1995, Wei T’o has focused on developing better solutions and answers to manufacturing and regulatory problems, which were identified during this full-scale production period in Canada. The new inventions were applied first to improving mass deacidification treatments because Wei T’o believed the preservation of research archive and library collections have the highest priority.

4. Progress in Mass Deacidification

Two new deacidification concentrates and non flammable liquefied gas solvent systems have been developed and tested with excellent results at the National Library of Canada. The nonflammable solvent 1,1,1,2-tetrafluoroethane (HFC-134a) is the major solvent component of both formulations. Dupont introduced HFC-134a in 1991, and it will be available for many decades in the foreseeable future. HFC-134a is a non flammable solvent, and has become the world wide standard for auto and domestic air conditioning refrigeration. It is also widely used as a foam-blowing agent and in pharmaceutical inhalers. HFC-134a is approved by EPA, Environment Canada, and UNESCO-UNEP as an alternative solvent for CFCs and HCFCs.

Although HFC-134a contains no chlorine and has no effect on the Ozone Layer, it does have a Global Warming Potential (GWP) of 1200 (100 yr. ITH, CO2=1) as a consequence of its great stability. This GWP is not considered an obstacle for use by libraries because its use in mass deacidification will have no effect on Global Warming. One hundred percent of the HFC-134a used will be recovered and recycled in future Wei T’o mass treatment facilities.

The use of many HFCs, including HFC-134a, as solvents will be limited to specific applications in future. Archives and libraries need to protect its continued place on the approved list for preservation work by advising their national environmental authorities of its value in mass deacidification treatments.

Both deacidification agents, methoxy magnesium methyl carbonate (MMMC) in methanol and isopropoxy magnesium isopropyl carbonate in isopropanol, produce equivalent deacidification results with HFC-134a. The MMMC agent is preferred because the recovered solvents are easier to recycle and the treated books have a lower odor level immediately following treatment; subsequently neither has an odor.

All of the inks and materials previously treatable in CFC and HCFC solvents are treated with equal or superior results in the new HFC-134a deacidification solutions. Many other inks, such as purple mimeograph and fast printing offset inks, previously avoided as extremely alcohol soluble and untreatable in Wei T’o CFC and HCFC solutions, also are absolutely unaffected.

The cause of ink instability is not the alcohol as previously believed, but rather the CFC and HCFC solvents. The only change is substitution of solvent HFC-134a for HCFC-22. Both of the HFC-134a solutions remains whiter, and the paper in treated books and documents shows less visual change and discoloration compared to books treated with CFC and HCFC solutions.

No books components previously preselected out were unusable or lost printed information following treatment with HFC-134a solutions. The defacement problems remaining in this group (films on paperback covers, binding adhesives, metallic cover inks, etc.) can be further reduced or avoided in future by improved treatment cycle control and equipment redesign. Covers and illustrations (including heavily inked, black images) exhibit far less bloom or white deposits. The books and their bindings are straighter, and text blocks are less distorted or expanded. Most binding adhesives in perfect bound and paperback books are unaffected. No leaves are loosened in perfect bindings as occurred previously. Spot pH tests showed all portions of treated books, including leaves deep inside spines of thick books, are thoroughly deacidified.

Results for alkaline reserve levels in full production are equivalent to previous results using CFC and HCFC formulations. Higher alkaline reserves are possible because the concentrates are more soluble in HFC-134a. This increased solubility of deacidification agent was unexpected because HFC solvents are known for their lower dissolving power than CFC solvents.

5. Single Sheet Treatments: Soft Spray Deacidification

Wei T’o will produce non flammable Soft Spray formulations containing the solvents HCFC-141b and HFC-134a with methoxy magnesium methyl carbonate in methanol as the deacidification agent for clients during an interim period as long as EPA permits its manufacture.

Wei T’o will offer a low or non flammable Soft Spray formulation containing only approved solvents and the isopropoxy magnesium isopropyl carbonate deacidification agent soon. This new formulation will have the advantages of low flammability, improved stability, and greatly reduced ink solubility.

Wei T’o is introducing four flammable Soft Spray solutions containing heptanes or isopentanes, and HFC-152a (a flammable, aerosol propellant approved by EPA, Environment Canada, and UNESCO-UNEP) with isopropoxy magnesium isopropyl carbonate as the deacidification agent. These formulations have greater stability, are less likely to clog the spray gun, have improved ability to penetrate and deacidify thick paper, and have lower potential to affect sensitive inks. The solvent vapors have a relatively non-hazardous Threshold Limit Value, safer than that of the HCFC Soft Spray. Their only disadvantage over earlier products is flammability. Two of the formulations are aerosol sprays, the other two reduce treatment cost by using nitrogen gas to pressurize on-site.

6. Single Sheet Treatments: Aerosol Spray and Solution Deacidification

Wei T’o will produce non flammable Aerosol Sprays #10, #11, and #12 containing the solvents HCFC-141b and HFC-134a and Solutions #2, #3, and #4 containing the solvent HCFC-141b with methoxy magnesium methyl carbonate in methanol or ethoxy magnesium ethyl carbonate as the deacidification agents during an interim period as long as EPA permits for clients who prefer these products.

Wei T’o will offer a low or non flammable Aerosol Spray and Solution containing approved and HFC solvents and the isopropoxy magnesium isopropyl carbonate deacidification agent soon. This formulation will have the advantages of improved stability and greatly reduced ink solubility.

Wei T’o is introducing two flammable Deacidification Aerosol Sprays and two Solutions containing heptanes or isopentanes, and HFC-152a (flammable propellant similar to HFC-134a) with isopropoxy magnesium isopropyl carbonate as the deacidification agent. Other than flammability, these new products have greater stability, are less likely to clog, improved ability to penetrate and deacidify thick paper and paperboard, and lower ability to affect sensitive inks. The solvent vapors will have a relatively low Threshold Limit Value, safer than those of the Wei T’o #10 and #11 sprays.

The properties of these new products are set out in the following table:

Spray #111 General Use Isopentanes >80% Isopropyl Alcohol <10% HFC-152a <8% PMPC* >2%
Spray #121 General Use Deep Penetration Low Aromatic Heptanes >80% Isopropyl Alcohol <10% HFC-152a <10% PMPC* >2%
Spray #131 General Use Low Flammability Coming Soon Isopropyl Alcohol HFC-152a PMPC*
Solution #115 General Use Isopentanes >87% Isopropyl Alcohol <12% PMPC* >2%
Solution #125 General Use Deep Penetration Low Aromatic Heptanes >87% Isopropyl Alcohol <12% PMPC* >2%
Solution #135 General Use Low Flammability Coming Soon Isopropyl Alcohol PMPC*

*PMPC=Isopropoxy Magnesium Isopropyl Carbonate dissolved in Isopropyl and Ethyl Alcohols

7. Testing

The 50 day accelerated aging study that commenced at CCI in late April was completed in mid July 1998. Two standard papers, a bleached Kraft book paper and a TMP newsprint, are used to evaluate the seven Wei T’o® spray and solution formulations listed on the following page. Preliminary results will be published promptly in an international journal. The formulas of the HC Regular and Deep Penetration aerosol sprays and solutions being evaluated are identical to the Good News Aerosol Sprays #111 and #121, and Solutions #115 and #125 now being introduced at the 1998 ALA Annual Meeting. The book and paper conservators of the National Archives of Canada are evaluating the aerosol sprays from the conservation viewpoint; and their comments will be included in the published report. I am sure that comments from ALA Preservation Librarians will also be welcomed.

8. End Notes

  1. This report has been revised since its initial presentation to ALCTS/PLMS Materials and Treatment Quality Discussion Group on 10 January 1998 during the 1998 mid-winter meeting of the American Library Association in New Orleans, LA.
  2. The new products are now available from conservation suppliers or directly from Wei T’o® Associates, Inc.

3. A patent application has been filed.

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