Books with blocked pages

Two references which I have found useful in trying to find an answer
to this problem are:

    Loomer, Joseph T, "Coated Papers", in: Handbook of Pulp & Paper
    Technology, Kenneth W. Britt (ed) (New York: Van Nostrand
    Reinhold Company), 2nd edn., 1970;

    Baker, Mary, Dianne van der Reyden, & Nancy Ravenel, "FTIR
    Analysis of Coated Papers, in: The Book and Paper Group Annual
    (Washington DC: AIC), vol.8, 1989.

Loomer gives a good explanation of the composition of coated papers,
which I have summarised here from his text:

Composition
Basic components for papers designed for the graphic arts:

    1.  Pigment(s)
    2.  Dispersant(s) for the pigment
    3.  Anti-foam (sometimes)
    4.  Adhesive(s), either synthetic or synthetic/natural binder
    5.  Flow modifiers and/or lubricants
    6.  Defoamers
    7.  Tinting colours

Pigments:
Most common pigments are:

    China clay
    Calcium carbonate
    Titanium dioxide
    Satin White (slaked lime and aluminum sulphate)
    Aluminum trihydrate

Usual combinations of pigment coatings are:

    1.  Clay 50 to 85%; Carbonate 50 to 15%
    2.  Clay 65 to 90%; Titanium dioxide 35 to 10%
    3.  Clay 75 to 90%; Satin White 25 to 10%
    4.  Clay 65 to 90%; Titanium dioxide 20 to 5%; Aluminum
        trihydrate 15 to 5%

Dispersants:
Pigments normally use polyphosphates; carbonates are dispersed with
modified sodium hexametaphosphate (Calgon T); auxiliary dispersants
may be sulphonated naptholene formaldehydes, sodium terpolymers,
phosphated potassium copolymers etc.  Casein, soy protein, and
oxidized starch can also be used.

Binders:
    Starch (corn, potato, tapioca, chemically or enzyme modified)
    Casein
    Soy bean protein
    Animal glue
    Synthetics - polyvinyl alcohol; synthetic latices
    (styrene-butadiene; acrylics; vinyl acetates; methylcellulose;
    carboxymethylcellulose; hydroxy ethyl cellulose, polyvinyl
    pyrrolidone)

Baker et al also discuss the composition of coated papers and list a
number of fillers that have been used:

    ground bone ash, white lead, calcium carbonate, gypsum, powdered
    cuttlebone, wax, zinc oxide, titanium dioxide, acrylic gesso,
    clay, talc, satin white (aluminum hydroxide, calcium hydroxide,
    and calcium sulphate), barium sulphate, calcium sulphate,
    calcium sulphite, or calcium carbonate.

They list binders used as:

    starch, mucilage, gums (i.e. gum arabic), gelatin and animal
    glues (hide glue), casein, modern latexes and synthetic resins
    (i.e. acrylic emulsions), peanut and soybean proteins.

Obviously, as Ellen McCrady says, there are likely to be other
synthetic components which have been added since Loomer's work was
published and are almost certainly an influencing factor (there are
many more) which will determine the success or failure of drying wet
coated paper.

David Tremain
Conservator, Preventive Conservation Services
CCI

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                  Conservation DistList Instance 11:51
                 Distributed: Tuesday, December 9, 1997
                       Message Id: cdl-11-51-003
                                  ***