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Publication numberUS3034922 A
Publication typeGrant
Publication dateMay 15, 1962
Filing dateJul 23, 1959
Priority dateAug 1, 1958
Also published asDE1149603B
Publication numberUS 3034922 A, US 3034922A, US-A-3034922, US3034922 A, US3034922A
InventorsHans Boe
Original AssigneeFreudenberg Carl Kg
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Water-soluble paper and method of making it
US 3034922 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

United States Patent 3,034,922 WATER-SOLUBLE PAPER AND METHOD OF MAKING IT Hans Bile, Augsburg, Germany, assignor to Firms Carl Freudenberg, Kommanditgesellsehaft auf Aktien, Weinheim-Bergstr., Germany No Drawing. Filed July 23, 1959, Ser. No. 828,943

Claims priority, application Germany Aug. 1, 1953 2 Claims. (Cl. 117-63) The essential process in the manufacture of paper is the felting of the fibres, which are necessary for the formation of the paper, in the shaking screen machine, leading to the formation of a fibrous mass which is no longer soluble in water. Paper, even when it is unsized, for example filter or blotting paper, is therefore insoluble in water. It is true that the paper fibres will swell and that the wet strength of the paper is lower than the dry strength, but the fibre bond remains stable, so that any wet paper can be dried and its original strength thus more or less restored.

If the paper is additionally sized, as for example with Writing paper, the material has great resistance to water and is stable and relatively unchanged even after remaining in contact with water for hours.

A paper which disintegrates into its component parts in water cannot therefore be produced by the normal papermaking method, as the felting of the paper fibres results in a bond which is stable even in water.

It has now been found that a paper which in water disintegrates into its individual components can be produced by impregnating with a suitable water-soluble and film-forming substance fibres which have been united to form a loose fibre fleece, for example by means of carding machines or fiat cards or by means of a Rando-Webb machine, thereupon drying them and forming the resulting material, if desired after re-wetting, into a paper-like product by calendering.

Natural and synthetic fibres, such as cotton, linen, hemp, ramie, Wool, viscose staple fibre, acetate staple fibre, Perlon, nylon, Trevira, polyvinyl alcohol fibres or alginate fibres, are suitable for this process.

Water-soluble, film-forming substances may be used as binders, such as for example methyl cellulose, cellulose glycolates, polyacrylic acid and acrylates, polymerisation products on a basis of vinyl pyrrolidone, polycarboxylic acids, water-soluble urea formaldehyde condensation products, decomposed glues, water-soluble starch products, dextrins, and sugars; alkali, ammonium, and triethanolamine alginates; carrageen moss solutions, alkali caseinates, or waterglass (alkali metal silicate). The amount of the water-soluble film-forming binder to be incorporated in the fibrous structure is preferably 40%- 100% of the weight of the fibres.

Known fillers, such as kaolin, chalk, talcum, gypsum, magnesite, pearl white, lithopone, titanium dioxide, kieselguhr, microcellulose, asbestos, and if desired emollients or hygroscopic media, such as glycerine, glycols, polyglcols, and urea, and if desired water-soluble dyestufis may be added to these binders and the loose fibre fleece may be impregnated with an aqueous mixture on any of the well-known machines, e.g. a screen saturator, and dried. The concentration of said aqueous mixture depends upon the type of the employed machine. Generally, the aqueous mixture should contain 5 to 50% of said film-forming binders and fillers. Those skilled in the art will find out the preferable concentration for a specific case without difiiculties. The amount of the fillers and emollients which may be added preferably amounts to 60%-200% of the weight of the dry fibers. The resulting intermediate product, after first being wetted "icethe handle and the smoothness of the finished material depends on the pressure and the temperature of the rolls.

Thus it ispossible to produce papers, which in water disintegrate into their constituents. The weight of such paper is about 40 grams per square metre for carbon copy paper, grams per square metre for writing papers, and to grams per square metre for book papers or the like. These papers can be written on normally with ink, ball point pen, or pencil, or used to make the normal number of carbon copies in the typewriter, and can just as easily be used for stencil duplicating. When the above mentioned papers are contacted with water, the binder material will be dissolved, thus releasing the individual fibres from the sheet and leaving a soft pulpy mass. This procedure takes only a few minutes. But even before the paper sheet has fully disintegrated, the writing on said paper becomes undecipherable immediately when subjecting it to the action of hot or cold water. Not only single sheets of paper, but even documents or books in which many sheets of this type are superimposed may be made undecipherable in this way.

The novel paper products are especially suitable for military purposes. So, radio operators no longer have to burn each sheet after reception and decoding of a cable. It is enough to destroy the text written on the novel paper products by dipping it into water.

The novel paper products are also suitable for the production of log books for battle ships and submarines. If such naval units should sink in shallow enemy coastal water, it is impossible for enemy divers to rescue and decipher the log books which may contain secret matter.

The invention will now be described with reference to the following typical examples in which the proportions given are by weight.

Example 1 A matted fibre fleece composed of 100% staple fibres with a weight of 24 grams per square metre is impregnated with an aqueous mixture containing:

30 parts of cellulose glycolate, 20 parts of maize dextrine,

15 parts of chalk,

15 parts of kaolin,

40 parts of gypsum,

1 part of wetting agent.

The intermediate product obtained after impregnating on a screen saturator and drying, with a Weight of about 80 grams per square metre, is smoothed, after wetting to a moisture content of about 5%, on a heated calender at about C., and cut. A smooth, strong writing paper is obtained, which swells on cold water in a few minutes and, after dissolution of the fibre bond, leaves behind a mixture of insoluble fibres.

Example 2 A carded fleece of 50% staple fibres and 50% polyamide fibres, with a weight of 60 grams per square metre, is impregnated with an aqueous mixture containing:

50 parts of polyacrylate, 10 parts of urea,

20 parts of gypsum,

10 parts of pearl white, 10 parts of talcum,

1 part of Wetting agent.

After impregnation and drying an intermediate product with a weight of 150 grams per square metre is obtained,

which is wetted and calendered with increasing pressure at about 150 C., and thereupon cut. If the resulting paper is soaked in water, it breaks up into its fibrous constituents.

Example 3 A longitudinally directed carded fleece, consisting of 25% polyamide fibres, 25% acetate staple fibres, 20% ramie, 30% cotton, with a weight of 16 grams per square metre, is impregnated with an aqueous mixture containmg:

33 parts of water-soluble starch, 5 parts of polyglycol,

15 parts of microcellulose,

20 parts of titanium dioxide,

20 parts of gypsum,

6 parts of lithopone,

1 part of wetting agent.

The impregnated and dried first stuff with a weight of about 40 grams per square metre is calendered, after wetting, with a roll temperature of about 100 C. This thinner paper disintegrates into its constituents after a very short time in water.

I claim:

1. In a method of producing a writing paper which in Water disintegrates into its individual components, the steps of impregnating a fleece of cardable textile fibres with an aqueous dispersion containing a water-insoluble filler material and a Water-soluble film-forming binder in such amounts as to incorporate said binder material in an amount of to 200 percent, based upon the weight of the dry fibre fleece, drying the thus resulting structure, re-wetting said dry structure to a moisture content of about 3 to 10 percent and smoothing it on a heated calender at a temperature between and C.

2. A writing paper which in water disintegrates into its individual components consisting of cardable textile fibres being bonded together with a Water-soluble filmforming binder and containing insoluble filler material.

References Cited in the file of this patent UNITED STATES PATENTS 1,518,944 Sulzberger Dec. 9, 1924 2,208,653 Whitehead July 23, 1940 2,402,542 Foote et al June 25, 1946 2,705,688 Ness et al Apr. 5, 1955 2,880,113 Drelich Mar. 31, 1959 2,893,754 Richter et al. July 7, 1959

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1518944 *Sep 13, 1920Dec 9, 1924Sulzberger NathanAsbestos paper, etc.
US2208653 *Sep 16, 1937Jul 23, 1940Celanese CorpSafety paper
US2402542 *Apr 22, 1943Jun 25, 1946American Bank Note CoCoated paper and method of making same
US2705688 *Apr 7, 1952Apr 5, 1955Chicopee Mfg CorpNonwoven fabric and method of producing same
US2880113 *Jan 11, 1956Mar 31, 1959Chicopee Mfg CorpDurable nonwoven fabric and method
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3259104 *Mar 13, 1962Jul 5, 1966Milton L GerberApparatus for manufacturing a product
US3431166 *Dec 27, 1967Mar 4, 1969Mishima Paper Mfg Co LtdMethod of making paper which dissolves in water containing papermaking fibers and fibrous cellulose-glycolic acid
US3594928 *Jun 13, 1968Jul 27, 1971Bristol Myers CoPaper having areas dissolvable in water
US3602225 *May 7, 1969Aug 31, 1971Fmc CorpBiodegradable absorbent pad
US3607359 *Jan 10, 1968Sep 21, 1971Freudenberg CarlProcess for the manufacture of unwoven fabrics bonded with a binding agent and having a smooth surface
US3610245 *Apr 10, 1969Oct 5, 1971Kimberly Clark CoFlushable wrapper for absorbent pads and pad covered therewith
US3640841 *Apr 29, 1969Feb 8, 1972Borden CoMethod for controlling adhesion of paper on yankee drier with polyamides and resultant products
US3903889 *Feb 16, 1973Sep 9, 1975First National Bank Of NevadaDisposable liquid absorbent products
US3936347 *Sep 3, 1974Feb 3, 1976Sumitomo Chemical Company, LimitedPaper composed mainly of pullulan fibers and method for producing the same
US3993640 *Dec 9, 1974Nov 23, 1976Laporte Industries LimitedTreatment of cellulosic materials
US4009313 *Aug 30, 1972Feb 22, 1977Minnesota Mining And Manufacturing CompanyEnzymatically dispersible non-woven webs
US4061468 *Jul 1, 1975Dec 6, 1977Boehringer Mannheim GmbhIndicator dye
US4124116 *Jan 25, 1978Nov 7, 1978Mccabe Jr Edward GLiquid absorbing sectional pack
US4224366 *Oct 19, 1978Sep 23, 1980Mccabe Jr Edward GDisintegrating barrier sheets; graft polymer of polyacrylonitrile-starch carboxylate salt as absorber
US4543410 *Jun 21, 1982Sep 24, 1985Morca, Inc.Absorbent cellulosic base structures
US4655382 *Nov 12, 1985Apr 7, 1987Raychem Corp.Water soluble laminate of paper and polymer coating
US4956300 *Oct 16, 1984Sep 11, 1990Helena Laboratories CorporationAdsorbent carrier having guaiac that will react with hemoglobin fresent to form a blue dye, oxidizers and binders
US5081040 *Jun 6, 1989Jan 14, 1992Helena Laboratories CorporationComposition and kit for testing for occult blood in human and animal excretions, fluids, or tissue matrixes
US5196167 *May 9, 1991Mar 23, 1993Helena Laboratories CorporationFecal occult blood test product with positive and negative controls
US5217874 *May 9, 1991Jun 8, 1993Helena Laboratories CorporationFecal occult blood test product with positive and negative controls
US5273888 *Apr 29, 1988Dec 28, 1993Helena Laboratories CorporationChemical test kit and method for determining the presence of blood in a specimen and for verifying the effectiveness of the chemicals
US5474545 *Dec 7, 1992Dec 12, 1995Chikazawa; OsamuDiaper and/or sanitary napkin
US5702913 *Jun 12, 1989Dec 30, 1997Helena Laboratories CorporationUsed for fetal specimens for occult blood
Classifications
U.S. Classification162/158, 162/100, 604/368, 604/364, 427/361, 162/157.3, 428/543, 427/364, 604/372, 162/140, 427/382, 524/2, 428/375, 604/375
International ClassificationD04H1/74, D04H1/645, D04H1/587, D21H17/28, D21H17/07, D21H17/43, D21H17/66, D21H17/27, D21H17/68, D21H17/06
Cooperative ClassificationD04H1/74, D21H17/07, D04H1/645, D21H17/68, D21H17/27, D21H17/66, D04H1/587, D21H17/06, D21H17/43, D21H17/28
European ClassificationD04H1/74, D04H1/645, D04H1/587, D21H17/43, D21H17/06, D21H17/68, D21H17/27, D21H17/28, D21H17/07, D21H17/66