US3702779A - Coating of webs by freeze-drying and products therefrom - Google Patents

Coating of webs by freeze-drying and products therefrom Download PDF

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US3702779A
US3702779A US3702779DA US3702779A US 3702779 A US3702779 A US 3702779A US 3702779D A US3702779D A US 3702779DA US 3702779 A US3702779 A US 3702779A
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coating
coated
paper
dried
freeze
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Thomas A Fadner
Karl V Kraske
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Ethyl Corp
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Ethyl Corp
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    • 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
    • D21H25/04—Physical treatment, e.g. heating, irradiating
    • D21H25/06—Physical treatment, e.g. heating, irradiating of impregnated or coated paper
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31725—Of polyamide
    • Y10T428/31768—Natural source-type polyamide [e.g., casein, gelatin, etc.]
    • Y10T428/31772—Next to cellulosic
    • Y10T428/31775—Paper
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31855—Of addition polymer from unsaturated monomers
    • Y10T428/3188—Next to cellulosic
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31942—Of aldehyde or ketone condensation product
    • Y10T428/31949—Next to cellulosic
    • Y10T428/31964—Paper
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31971—Of carbohydrate
    • Y10T428/31975—Of cellulosic next to another carbohydrate

Definitions

  • Coated paper is produced by applying a composition comprising a polymeric material with or without added plgments dispersed in a liquid vehicle, freezing the coatmg, subjecting the frozen coating to a vacuum to remove the majority of the liquid vehicle, and returning the dried or partially dried coating on the web to ambient temperature.
  • this prior art two-phase coating technology results in a more or less random distribution of the material surrounding these voids. Variations as great as fold are common. A physical configuration of this type will have little structural strength. The thin membranes will break readily under compressive, shearing or printing forces. Thus, with the two-phase coating systems, smooth, printable coatings are diflicult to obtain without either adding pigments, using a subsequent surface treatment, or overcoating. All of these treatments, however, serve to reduce the appearance, optical properties, lightweight and/or economical advantages which might otherwise be characteristic of these coatings.
  • plastic or resinous compositions have been formed into porous films for application onto a backing material.
  • the porous film is formed by first freezing a dispersion or emulsion of the composition. The freezing produces expanded ice structures in the mass; whereupon, subsequent thawing produces a resinous mass which is generally sponge like. The thawed mass is then broken down into a moldable or coatable composition. This composition can be applied to a suitable backing material; and with the application of heat, the dispersing medium is removed and the composition fused together into a porous film.
  • the present invention provides a method which permits the direct production of a lightweight coating with high smoothness and opacity without necessity for subsequent smoothing, coating or surface treating operations and without the necessity of using a cumbersome twophase liquid system.
  • the coated product is one which is formed by coating a web or sheet of paper with a mixture consisting of a polymeric material dispersed in a liquid vehicle with or without pigments and adhesives, freezing the applied coating before the vehicle has evaporated or been substantially absorbed into the paper, introducing the frozen coated sheet into a vacuum chamber where liquid vehicle is substantially sublimed away from the frozen coating, and returning the substantially dried web to normal temperature.
  • the thickness of the dried coatings prepared according to this disclosure remain substantially the same as its wet thickness when freshly applied to the substrate.
  • the surface of the coating thus prepared has substantially the same high degree of smoothness and gloss as the wet coating at the time it was frozen.
  • the opacity of the resulting lightweight coating is markedly improved over an equivalent weight of the best known conventionally dried pigmented coatings. Further advantages of the coatings of this invention include low density and high gloss.
  • the dried coating thickness is also substantially the same as the wet thickness.
  • the invention is particularly advantageous for the continuous manufacture of lightweight opaque printing paper.
  • Coated paper products of this invention are readily made water insensitive, of high brightness and of strength commensurate with that encountered in known conventional printing processes.
  • Freeze-drying as a process is well known and has been used in the food industry for a number of years. However, it has generally been considered merely as a means for removing water from, for instance, a food product without damaging the material, that is, without destroying its natural structure as would occur for instance by normal high temperature drying processes.
  • one of the desirable properties which has been obtained is ease of subsequent water recovery into the solid when the product is later to be used, that is, water could be restored to the solid rapidly because the resulting product was extremely porous.
  • this water-regain property is highly undesirable in coated papers and we have therefore, developed coatings which attain a high degree of water resistance, even though dried by the freeze-drying process.
  • the drawing is a schematic view showing the components of the processing equipment for carrying out the process of this invention.
  • polymeric materials that can be used according to this invention either alone or in admixture include all polymeric materials capable of being coated on a substrate such as paper and particularly those used in the paper industry and well known to those skilled in the art.
  • polymeric materials that appear particularly advantageous include starch, dextrine, casein, soya protein, polyvinyl alcohol, regenerated cellulose, poly (styrene/maleic anhydride), poly (styrene/butadiene), acrylic polymers and copolymeric mixtures thereof, and the like.
  • formulations at a solids level between 5% and 60% by weight and even more preferably between 15% and 40% by weight in a single phase liquid carrier.
  • Organic and inorganic pigments which are well known in the paper coating art may be added to the formulation in essentially any proportion for special effect such as color, but some special opacifying pigments such as rutile titanium dioxide actually decrease the opacifying power of the freeze-dried coating when compared on a pound for pound basis with a similar coating not containing the pigment. Except as indicated herein, the coating formulation need not be treated physically or chemically in any unusual way prior to its application to the web.
  • Pigments are included in conventional paper coatings not only to increase opacity and whiteness of the coating, but also to provide microporosity necessary to trap printing ink, thereby preventing setolf from one sheet to another during printing, and to allow adequate ink pickup during printing to obtain desired image density.
  • pigments which can be used include coating clays, zinc oxide, titanium dioxide and satin white.
  • the freeze-dried coatings according to this invention contributes similarly to these aspects of the printing process and produce printing results superior to conventional coatings.
  • One method for assuring adequate strength in the final coating involves preparing formulations consisting of two or more dissimilar polymeric materials.
  • the freeze-dried coatings prepared from such systems exhibit unexpected strength. Although the exact reasons for this unexpected strength are not known, it is believed that these systems obtain their strength by virtue of the fact that freezing does not actually occur instantaneously regardless of how fast the coating appears to have been frozen. We have postulated that certain molecular regions within the coating are probably occupied by dissimilar functional groups from polymeric molecules and that some water molecules do not become frozen even at apparent ambient temperatures as low as minus C.
  • dissimilar polymers i.e. those having dissimilar functional groups such as in Example VII, can be used according to this invention to obtain sufiicient strength in the coating for printing purposes.
  • Another method for achieving strength in freeze-dried coatings involves freezing the coating slowly and limiting the final temperature to which the frozen coating is subjected, that is maintaining the temperature as high as possible and yet retain a frozen coating. Whether or not dissimilar polymer materials are used, this approach accomplishes substantially the same effect as the immediately preceding method. Thus, it is believed that all of the polymeric molecules would be associated with sufiicient liquid vehicle molecules to permit good intermolecular bonding while the crystals of vehicle which have been allowed to grow to the desired size provide the void spaces which contribute to the exceptionally high opacity characteristics of the freeze-dried coatings made accord ing to this invention.
  • Another technique involves the addition of an emulsified thermoplastic or heat fusible material to the coating formulation, for instance, in the case of an aqueous system, an acrylic emulsion polymer or a wax emulsion respectively.
  • an emulsified thermoplastic or heat fusible material for instance, in the case of an aqueous system, an acrylic emulsion polymer or a wax emulsion respectively.
  • the coating after the coating has been freeze dried, it is subject to a source of heat suflicient to cause fiow of the thermoplastic or fusible material, thereby effecting substantial intermolecular bonding.
  • Such coated products when subsequently returned to normal temperatures have the strength required of a printing coating as illustrated in Example XVI. It should be apparent that the major polymeric ingredient of the coating must not have thermoplastic or fusion properties similar to the ad ditive just described. Different functional groups are not required using this technique.
  • Another technique of imparting strength to a freezedried coating according to this invention involves subjecting the coating to a bond forming chemical reaction after the coating has been dried wherein at least one part of the reacting system is added to the coating after it has been dried. In this case, it is desirable to limit the quantity of reactive material taken up by the dried coating so as not to impair the inherent opacity of the coating.
  • Typical reaction system might include vapor phase isocyanate reactions, epoxy reactions, carboxyl, amine formaldehyde,
  • the processing equipment required for practice of this invention is unique in that the various components necessary to the invention have to our knowledge, never been assembled into one apparatus, despite the fact that each of the major components exist and are well known to those schooled in the art of coating, vacuum treatment of webs, and freeze drying. That is to say, the process equipment necessary to this invention is made up of a series of already known operational units. The overall process is described in the following paragraphs.
  • the coating unit may be selected from any of the types which can apply fluids of suitable rheology so as to obtain desired coat weight within desired tolerances when applied to a paper web.
  • trailing blade inverted blade, air knife, roll coating, reverse roll coating, wire wound rod doctor, extrusion or any of the other well-known techniques for applying coatings to a web may be employed.
  • This list is intended to express the breadth and scope of our invention and not to limit the applicable techniques to those named.
  • the freezing step may be carried out by any one of several techniques.
  • a blast. of cold air or other gas may be used, the sheet may be brought into contact with the cold surface, such as for instance, the chilled backing roll for a trailing blade, or a large chilled drum roll, or the sheet may be dipped into a cold immiscible non-wetting fluid, each of which is known in various segments of industry which utilize freezing as a process operation.
  • This portion of the process involves passing the web through for instance, rotary seals or narrow slits into succeeding chambers at lower pressure.
  • Each chamber can be individually pumped and can be of very low volume. The number of such entry and exit chambers required will depend upon the efiiciency of the rotary seals and the capacity of the pumps.
  • This heat may be supplied in a number of ways, for instance, by use of microwave or dielectric heaters, infrared radiation, electrical resistance through a conductive material and many others. It is important, however, during the sublimation process that the coating not be grossly melted thereby destroying the porous structure.
  • the heat exchangers are maintained at a temperature well below the ice point characteristic of the operating pressure, which temperature is consequently also below the temperature of the coated web.
  • a second or alternate heat exchanger can also be provided so that the ice buildup on the primary heat exchanger may be removed without interrupting the continuous operation.
  • the web After the web has been dried in the vacuum chamber, it is led out of the chamber through a similar set of seals, given a further heat or chemical treatment if desired, then rewound into a roll.
  • the same process can serve for a sheet which has been coated on either one side or two, with only minor modifications to the geometry required for a two-side coated sheet as will be recognized by those skilled in the art.
  • the wet coated sheet could be lead directly into the vacuum chamber without necessity for first freezing the coating.
  • the overall process remains similar in this case, since the coating will freeze rapidly in the vacuum due to the cooling effect of the vaporization. Once frozen in this man- 7 ner, the process continues substantially as we have already described. This is illustrated by the Example XVII disclosed herein.
  • the coatings that can be used according to this invention can comprise conventional paper coating compositions having solids contents in the usual and conventional range of coat weights or wet thicknesses as previously practiced in the paper industry. With respect to wet thickness of the coating, it is significant to point out that the coatings according to this invention have the same thickness both wet and dry, while conventional air drying of these same coatings reduces the thickness of the wet coatings.
  • the invention is of course not limited to paper but can be practiced on various substrates, such as plastic films, particularly where the applied coating is to be printed.
  • EXAMPLE I A sheet of paper rawstock having a basis weight 44 pounds per 3300 sq. ft. was placed on a metal plate cooled by Dry Ice. A coating formulation consisting of aqueous ammonium caseinate, at 15% by weight solids was applied to the sheet by means of a Bird Film Applicator at a rate of 2 pounds of solids per 3300 sq. ft. and frozen immediately. The paper was placed in a vacuum chamber and evacuated to 500 microns and held there until the frozen coating was dried by sublimation and then returned to ambient conditions. The drying only took about 2 minutes. Casein, freeze dried in the above manner forms an opaque, white coating with an exceptionally smooth, glossy surface. The properties of the paper were considerably improved by the coating as noted below:
  • EXAMPLE II A coating formulation containing 80% casein and 20% of paraffin wax emulsion (Paracol 404 g.) at 15% total solids was coated on paper and freeze dried as in Example I. The film was white and opaque and after a heat treatment at 100 C. for 1 minute was substantially water resistant.
  • paraffin wax emulsion Paraffin wax emulsion
  • EXAMPLE IV A coating formulation consisting of 68% casein and 32% of a 55% solids styrene/butadiene copolymer (60/ 40) latex, marketed by Koppers under the name Dylex K-55, was coated at 15% total solids on a paper web as in Example I. This coating was white and opaque and more resistant to water than the coating of Example I.
  • EXAMPLE v A coating formualtion consisting of 78% casein, 19.5% of methylated methylol melamine-formaldehyde resin, marketed by Monsanto under the trade name Scriptite 31, and 2.5% diammonium phosphate was coated on paper at 15% total solids and frozen as in Example I. The freeze-dried coating was then cured for 20 seconds at 180 C. The film produced was white, opaque and water resistant.
  • EXAMPLE VII A coating formulation consisting of 68% dextrine and 32% of a partial ester of a maleic anhydride-styrene copolymer, marketed by Monsanto Chemical Company under the trademark Scripset 550, was applied and freeze dried at 23% total solids as in Example I.
  • the coating was white, opaque, and water resistant.
  • the Shefiield smoothness was 10 and the Hunter gloss measured which indicated a smoother surface than was attained using casein or protein.
  • EXAMPLE VIII A coating formulation containing HT clay and 20% oxidized starch at 40% total solids was coated on paper and freeze dried as in Example I, and compared to a conventionally air-dried sheet with the same coating and coat weight. Freeze-drying improved the brightness from 80 to 86, the opacity from 90 to 94, and tripled the Bekk smoothness 80 to 2140.
  • EXAMPLE IX A coating formulation containing 80% HT clay and 20% polyvinyl alcohol at 20% total solids was coated on paper and freeze dried as in Example I and compared to an air-dried control with the same coat weight. The brightness on the control was 77 and the opacity 87. The freeze-dried sheet had a brightness of 85.5 and an opacity of 92.5.
  • Example VII The coating formulation described in Example VII was applied as in Example I at 23% total solids and put in the vacuum chamber and kept frozen while the chamber was evacuated. At 1000 microns total pressure the sheet was removed from the cold metal support and suspended parallel to an infrared heater in vacuum which was turned on at a wire temperature of 1200 C. for 10 seconds. The chamber was then returned to atmospheric pressure and the coating was found to be dry. The total time that the paper was in the vacuum was 2 minutes. The coat weight was measured at 5.5 lbs, per ream and the gloss and smoothness corresponded to those measured in Example VII.
  • EXAMPLE XI An aqueous casein coating formulation at 15% solids was applied to paper rawstock and allowed to penetrate for 1 second before freezing on a cold metal plate and freeze-drying as in Example I. The coating produced had a fiber tearing bond to the paper and similar properties described in Example I.
  • EXAMPLE XII A coating formulation consisting of oxidized starch (Stayco C) at 15 solids was applied as in Example I and freeze dried. A 5.4 lb./ream coating raised the papers brightness from 79 to 88 and its opacity from to 94. The sheet was smooth and glossy.
  • Example XIII The product of Example XIII is smoother than conventionally coated, air-dried, supercalendered products.
  • the apparent density of Example XIII coating is substantially the same as that for its base stock, which compares favorably with conventional products where the product density is typically doubled to achieve product properties comparable to those of Example XIII.
  • EXAMPLE XIV An aqueous formulation containing 75 parts of ammonia cut Polish casein, 7.5 parts of Azite and 200 parts of HT clay (kaolinite, :Edgar Clay Company), at 41.4% solids was applied to a 34 /2 pounds per 3300 square feet paper base, immediately frozen and vacuum dried as described in Example XIII. The characteristics of the resulting dried, coated sheet are given below:
  • a coating formulation containing 100 parts of enzymeconverted starch, 600 parts of No. 2 coating clay and 100 parts of calcium carbonate (Purecal 0, Wyandotte Chemical Co.), dispersed in 600 parts of water to 58% solids was applied in a manner similar to that described in Example XIII.
  • the dried product characteristics are listed below:
  • Example XV To apply the coating composition of Example XV to a paper in the conventional manner with supercalendering would require twice the coating weight to obtain opacity and brightness values approaching those of Example XV. Also, higher densities; would be required.
  • EXAMPLE XVI An aqueous coating formulation containing by weight parts of a 15% ammoniacal Polish casein dispersion, 32.6 parts of an acrylic emulsion polymer (Rhoplex AC-73, Rohm and Haas Company), 2 parts of a condensation product of melamine and formaldehyde, marketed by American Cyanamid Company as 'Parez'613 and 0.64 part of a 25% ammonium chloride solution was freeze dry coated in a manner similar to Example I. The dried coated paper was then heated for 30 seconds at C. Strength improvement was noted by a marked increase in resistance of the coating to marking by a metal stylus.
  • EXAMPLE XVII An aqueous coating formulation containing 100 parts by weight of casein, 25 parts of a styrene-maleic anhydride copolymer marketed by Monsanto Chemical Company as Scripset 54 and 25 parts of a synthetic rubber emulsion polymer marketed by E. I. du Pont, Inc. as a Neoprene emulsion, was applied to a paper base, placed in a vacuum chamber and evacuated to about 250 microns and held there until the coating was dried, re- Sliltd in an opaque coating having a brightness value 0 84.
  • coated products produced according to the above examples have various degrees of strength depending upon the particular process used as discussed above, but all are useful and the particular method chosen will depend upon the particular end use intended for the coated substrate. Dilferent printing processes, for example, require different coating strengths or tack strength as is well known in the art.
  • the coated substrates can of course be used for purposes other than printing where higher opacity, brightness, and smoothness are desired.
  • the coatings of this invention allow greater latitude in the design of printing paper products than heretofore possible.
  • rawstocks having base weights in the range from about 15 to 80 pounds per 3300 sq. ft. can be used, with or without added pigments or fillers to manufacture products of essentially nonvarying, low apparent density but ranging from about 3.0 to 6.0 mils in caliper.
  • coatings of this invention having substantially greater thicknesses than the prior art coatings can be used to produce coated products having total thicknesses comparable to prior art products.
  • coatings produced in accordance with the teachings of the present invention are uniform in thickness and may range from about 0.1 to 10 mils.
  • coatings of the present in vention are chaarcterized as having anhywhere from 20 to 90% void volume where the void volume is made up of numerous cells which may range from 0.1 to microns in size.
  • the size of the voids advantageously varies no more than about four fold.
  • the intervoid thickness of the coatings of the present invention Will be substantially uniform to form a continuous matrix surrounding the voids.
  • the intervoid distances may vary from 0.1 to 5 microns; with these distances in any particular application varying only from about two to four fold.
  • the density of the coated product is substantially the same as that of the base material to which the coating is applied. More particularly, the density of the coating may range from 0.06 to 1.2 grams per cubic centimeter with the density of the coated product being no greater than 20% more than the density of the original base material.
  • Paper products coated in accordance with the teachings of the present invention generally have TAPPI opacity values ranging from 90 to 100, standard brightness values ranging from 80 to 100, Shefiield smoothness values ranging from about to 50, apparent density values from about 10 to 18 pounds per 3300 sq. ft. per mil of product thickness, good to excellent printability and good marring and crush resistance.
  • the present invention offers a technique of producing a high quality lightweight opaque printing paper surface having gloss, smoothness and inherent printability qualities so that the usual subsequent operation of supercalendering may be entirely eliminated. Elimination of the supercalendering step reduces the need for capital and labor in the manufacture of coated papers and eliminates a high wastage of product and time normally associated with the supercalendering step.
  • the polymeric materials for use in our coating compositions can be selected from a wide variety of natural polymers such as casein and starches and their chemical modifications, as well as addition-type polymers and copolymers of vinyl chloride, acrylonitrite, styrene, acrylic and methacrylic acid and their polymerizable derivatives, ethylene, butadiene, vinyl acetate, fiuorinated monomers and the like, and also from condensation polymers such as polyesters, polyamides, phenol-formaldehyde resins and the like, provided that the dried residue of these polymeric compositions is a solid, more or less permanent mass substantially as illustrated by the examples in this disclosure and that the composition can be dissolved, dispersed or otherwise suspended in a liquid medium which can be frozen and sublimed under reduce pressure in accordance with our disclosure.
  • thermal energy is applied to the frozen web under reduced pressure.
  • thermal energy is applied to the frozen web under reduced pressure in the form of infrared radiation.
  • thermal energy is applied by microwave or dielectric heating.
  • thermal energy is applied by conduction from a heated contacting surface.
  • the liquid vehicle is water
  • the polymeric composition is selected from at least one member of the group consisting of starch, oxidized starch, dextrine, casein, soya protein, polyvinyl alcohol, styrene-butadiene copolymers, emulsified wax, and partial esters of styrene-maleic anhydride copolymers.
  • the liquid vehicle is water
  • one is selected from at least one member of the group consisting of starch, oxidized starch, casein, soya protein, dextrine or polyvinyl alcohol, and
  • the second is selected from at least one member of the group consisting of polymers of melamine-formaldehyde or urea-formaldehyde, partial esters of styrene-maleic anhydride copolymers, styrene-butadiene copolymers and emulsified waxes.
  • the liquid vehicle is water
  • the polymeric composition is selected from at least one member of the group consisting of starch, oxidized starch, dextrine, casein, soya protein, polyvinyl alcohol, styrene-butadiene copolymers, emulsified wax, or partial esters of styrene-maleic anhydride copolymers.
  • liquid vehicle is Water
  • one is selected from at least one member of the group consisting of starch, oxidized starch, casein, soya protein, dextrine and polyvinyl alcohol, and
  • the second is selected from at least one member of the group consisting of pre-polymers of melamine-formaldehyde prepolymers of ureaformaldehyde, partial esters of styrene-maleic anhydride copolymers, styrene-butadiene copolymers, and emulsified wax.
  • the adhesive is at least one member of the group consisting of polystyrene and a cross-linkable styrene copolymer.
  • the liquified composition coated on the web contains an inorganic pigment.
  • (a) up to about 60 percent by weight of the polymeric 13 composition is replaced with inorganic pigments selected from at least one member of the group consisting of coating clays, zinc oxide, titanium dioxide, and satin white.
  • the coating of the Web contains a polymeric composition chemically reactive with at least one member of the group consisting of isocyanate, epoxy, carboxyl, amine, hydroxy containing compounds and formaldehyde;
  • a coated product comprising:
  • a coated product comprising:
  • a coated product comprising:
  • said coating contains an inorganic pigment.
  • said inorganic pigment is selected from at least one member of the group consisting of coating clays, zinc oxide, titanium dioxide, and satin white.
  • the polymeric composition is selected from at least one member of the group consisting of starch, oxidized starch, dextrine, casein, soya protein, polyvinyl alcohol, styrene butadiene copolymers, emulsified wax, and partial esters of styrene-maleic anhydried copolymers.
  • the polymeric composition consists of dissimilar polymeric materials.
  • one of the polymeric materials is one selected from at least one member of the group consisting of starch, oxidized starch, casein, soya protein, dextrine or polyvinyl alcohol;
  • another of the polymeric materials is one selected from at least one member of the group consisting of polymers of melamine-formaldehyde or urea-formaldehyde, partial esters of styrene-maleic anhydride copolymers, styrene-butadiene copolymers and emulsified waxes.
  • the apparent density of said product is no more than about 20% greater than that of said base material.
  • the apparent density of said coating is from between about .06 to 1.2 grams per cubic centimeter.
  • said voids are uniformly spaced throughout said coating.
  • said voids vary up to about four fold in size.
  • the intervoid distances of said coating vary from about two to four fold.

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US3702779D 1968-07-31 1970-04-21 Coating of webs by freeze-drying and products therefrom Expired - Lifetime US3702779A (en)

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US74900868A 1968-07-31 1968-07-31
US3057170A 1970-04-21 1970-04-21

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DE (1) DE1938162C3 (de)
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Cited By (12)

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US3791266A (en) * 1971-11-15 1974-02-12 B Bucalo Method and apparatus for manufacturing toilet paper rolls
US4146669A (en) * 1976-04-06 1979-03-27 Tsentralny Nauchno-Issledovatelsky Institut Bumagi (Tsniib) Crosslinking agent, method of producing same and paper made with the use thereof
US4624868A (en) * 1979-12-17 1986-11-25 Colgate-Palmolive Company Borated polysaccharide absorbents and absorbent products
US4902536A (en) * 1986-08-21 1990-02-20 Mtu Motoren-Und Turbinen-Union Munchen Gmbh Method of producing a protective layer on a structural part
WO2001049935A1 (en) * 1999-12-30 2001-07-12 Sca Hygiene Products Gmbh A method of applying frozen treatment chemicals to a fiber-based planar product and resulting products
WO2005083176A1 (en) * 2004-02-27 2005-09-09 Conservacion De Sustratos Celulosicos S.L. Process for preservation of cellulosic materials
WO2007100667A2 (en) 2006-02-23 2007-09-07 Meadwestvaco Corporation Method for treating a substrate
DE102006022201A1 (de) * 2006-05-12 2007-11-15 Kremer, Jens Fliesslinien- und Kristallisationsbeschreibung
US20080230001A1 (en) * 2006-02-23 2008-09-25 Meadwestvaco Corporation Method for treating a substrate
US20090181315A1 (en) * 2006-05-30 2009-07-16 Max-Planck-Gesellschaft Zur Foerderung Der Wissenschaflen E.V. Production of micro- and nanopore mass arrangements by self-organization of nanoparticles and sublimation technology
US20170175257A1 (en) * 2012-09-19 2017-06-22 Fresenius Medical Care Deutschland Gmbh Apparatus for manufacturing an adhesive-free gas barrier film having a ceramic barrier layer
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AT391721B (de) * 1986-12-30 1990-11-26 Republik Oesterreich Diese Ver Verfahren und vorrichtung zur konservatorischen behandlung von papier
DE59704054D1 (de) 1996-03-13 2001-08-23 Omya Ag Oftringen Streichfarbe

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US3791266A (en) * 1971-11-15 1974-02-12 B Bucalo Method and apparatus for manufacturing toilet paper rolls
US4146669A (en) * 1976-04-06 1979-03-27 Tsentralny Nauchno-Issledovatelsky Institut Bumagi (Tsniib) Crosslinking agent, method of producing same and paper made with the use thereof
US4624868A (en) * 1979-12-17 1986-11-25 Colgate-Palmolive Company Borated polysaccharide absorbents and absorbent products
US4902536A (en) * 1986-08-21 1990-02-20 Mtu Motoren-Und Turbinen-Union Munchen Gmbh Method of producing a protective layer on a structural part
WO2001049935A1 (en) * 1999-12-30 2001-07-12 Sca Hygiene Products Gmbh A method of applying frozen treatment chemicals to a fiber-based planar product and resulting products
US20080017336A1 (en) * 2004-02-27 2008-01-24 Wolfgang Wachter Process For Preservation Of Cellulosic Materials
WO2005083176A1 (en) * 2004-02-27 2005-09-09 Conservacion De Sustratos Celulosicos S.L. Process for preservation of cellulosic materials
US20080254298A1 (en) * 2006-02-23 2008-10-16 Meadwestvaco Corporation Method for treating a substrate
EP1987110A4 (de) * 2006-02-23 2009-11-11 Meadwestvaco Corp Verfahren zur substratbehandlung
US20080230001A1 (en) * 2006-02-23 2008-09-25 Meadwestvaco Corporation Method for treating a substrate
WO2007100667A2 (en) 2006-02-23 2007-09-07 Meadwestvaco Corporation Method for treating a substrate
US20080268158A1 (en) * 2006-02-23 2008-10-30 Meadwestvaco Corporation Method for treating a substrate
EP1987110A2 (de) * 2006-02-23 2008-11-05 MeadWestvaco Corporation Verfahren zur substratbehandlung
US8673398B2 (en) 2006-02-23 2014-03-18 Meadwestvaco Corporation Method for treating a substrate
US8349443B2 (en) * 2006-02-23 2013-01-08 Meadwestvaco Corporation Method for treating a substrate
DE102006022201A1 (de) * 2006-05-12 2007-11-15 Kremer, Jens Fliesslinien- und Kristallisationsbeschreibung
US20090181315A1 (en) * 2006-05-30 2009-07-16 Max-Planck-Gesellschaft Zur Foerderung Der Wissenschaflen E.V. Production of micro- and nanopore mass arrangements by self-organization of nanoparticles and sublimation technology
US20170175257A1 (en) * 2012-09-19 2017-06-22 Fresenius Medical Care Deutschland Gmbh Apparatus for manufacturing an adhesive-free gas barrier film having a ceramic barrier layer
US11175092B2 (en) * 2016-10-10 2021-11-16 Purdue Research Foundation Continuous roll-to-roll freeze-drying system and process
US20220074662A1 (en) * 2016-10-10 2022-03-10 Purdue Research Foundation Continuous roll-to-roll freeze-drying system and process
US11592236B2 (en) * 2016-10-10 2023-02-28 Purdue Research Foundation Continuous roll-to-roll freeze-drying system and process

Also Published As

Publication number Publication date
DE1938162B2 (de) 1974-04-11
DE1938162C3 (de) 1974-11-14
DE1938162A1 (de) 1970-02-05
GB1271281A (en) 1972-04-19
FR2014098A1 (de) 1970-04-10

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