US2038118A - Decalcomania paper - Google Patents

Description

April 21, 1936. J. M LAURlN 2,038,118

DECALCOMANIA PAPER Filed Sept. 17, 1934 Invcnforr" Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE I nacawzm ram Q m MacLaurln, Ware, mu. Application September 17, 1934, Serial N0. 744,396 7 Claims. (Cl- 1-33) This invention relates to decalcomanias, to the methods of using them, and to papers on which decalcomania designs are printed.

It has been the common practice for many years to make decalcomania papers by applying suitable water soluble coatings to the surface of an unsized backing sheet of paper. The decalcomania design or other printed matter is printed on the coating so applied and this coating is given characteristics which facilitate the printing operations. An unsized or so-called water leaf" paper has always been used for the backing sheet in order to facilitate the penetration oi the sheet by the water used for the purpose of releasing it from the decalcomania design at the desired stage in the process of applying the decalcomania to an article of work. A backing sheet of nature has the disadvantage, however, of being readily affected bychanges in atmospheric humidity. This is not an especially serious matter with small sheets, but it does become an exceedingly troublesome factor when the sheets are large, the decalcomania design requires several printings, and accurate registration is necessary. This is true, for example, in lithographic work where as many as twenty printings may be necessary. There, the dimculties occasioned by changes in atmospheric humidity are greatly increased due to the variations produced by it in the dimensions of the sheets and the resultant interference with accurate registration.

This diiiiculty has long been recognized, and

it has been attempted to overcome it by humidifying the plants in which decalcomania papers arefprinted. This expedient, however, is only a partial remedy in many climates for the reason that the humidifying apparatus is designed to add"moisture to the atmosphere and it can,

therefore, buildup the humidityto the desired point, but itcannot take excess moisture outof theatmosphere. Consequently, when excessivehumidity ls; present in the atmosphere, the desired conditionscannotbe maintained, and frequejntly'it-is impossible torunwork of this char- 'a'cter of theseunusual atmospheric conditions.,, 1 v,= 1

The present'invention deals with thisproblem andlit'jaims' todevise a decalcomaniapaper' and .a method, or. ,using it .whichwill substantially avoid theldiiilculties above described.

I' have found 'that these difficulties can be overcome by substituting a sized paper for the water leaf backingsheet and then using a special m 1 mm. t was h w m h e from the decalcomania design when the latter is applied to the work.

For the backing sheet the ordinary sized papers of good quality are suitable, care being taken, of course, to select a paper having the 5 proper strength, texture and weight. Preferably the sheet is sized with a rosin sizing and this constituent may be incorporated in the paper by any of the ordinary sizing methods such as tub, beater or engine sizing, no change in the ordinary sizing practices being required for the purposes of this invention. It is desirable to use a suflicient proportion of sizing to substantially increase the waterproofing properties of the paper, the term waterproofing" being here used in the sense in which it is ordinarily employed in the paper making industry and as applied, for example, to writing papers. A sufllcient proportion of sizing should be used to prevent the paper from undergoing any substantial changes in dimensions due simply to variations in atmospheric humidity, or, in other words, to make the paper stable under wide variations in such humidity.

The usual methods of manufacturing decalcomania paper can be followed in making such a product with a sized backing sheet. A typical process consists in coating the surface of the paper with starch and then building up on this coating an outer coating of dextrine, care being so taken .to produce a smooth outer surface having the desired characteristics for printing. In some cases a lacquer coat is applied on top of the dextrine coat, or metal powders are used in one of these outer coats, various modifications being made in the final coating operation to suit the requirements of special cases. The paper so prepared is shipped to the printer who prints the desired design, or other subject matter, on the .outer coating. These decalcomania sheets are printing. A reasonable degree of speed is ordi-- narily required in this operation, a typical stipulation being that the release of the'backing sheet must be effected in twenty seconds after the apv plication of the water or other releasing liquid. It would be impossible to effect the release of a sized sheet in this length of time simply by applyingwatertoit. Thepresenceofthesizing constituents so retard the penetration of the water that a substantially longer time is required for this releasing operation when a sized backing sheet is used than when the ordinary water leaf backing sheet is employed.

Ihavefoundhoweventhatthisdiflioultycan be overcome by introducing substances into the water which will so reduce the surface tension ofthewaterthatitwillpenetratethesheetat a rate much. higher than that. due simply to the capillary attraction of the paper for water alone. In addition. substances can, if desired, be added tothewaterwhichwillactdirectlyontheparticlesofsizingmaterialtosoftenthemandthereby to facilitate the releasing action. For example, ordinary grain alcohol mixed with water will improve its penetrating rate. A more economical substance is sulphonated castor oil, 10% of which mixed with water produces a very satisfactory releasing liquid. Other sulphonated vesetable oils can be used with substantially as good results. The best materials, however, which I have so far discovered are the sulphonated higher alcohols, such as lauryl, myristyl or stearyl alcohol. These alcohols are solid at ordinary temperatures and are commonly referred to as higher" alcohols because of the greater number of methyl (CH1) groups which they contain. The usual process of making sulphonated alcohols of this type consists in sulphonating the mixture of alcohols obtained from cocoanut or palm oil, neutralizing the product so obtained, heating to a higher temperature in a finely divided state, and then cooling rapidly. The sulphonating process usually consists in treating the material with concentrated sulphuric acid, generally at a somewhat elevated temperature, this treatment resulting in taking water out of the treated material and replacing it with the sulphonic radical (SOzOH) These sulphonated higher alcohols are readily obtainable in the market. Typical products of this character are sold under the names of Nekal and Gardinol. From 5% to 2.0% of one of these substances, dissolved in water, produces a solution which penetrates a sized backing sheet very rapidly and effects the release of the decalcomania well within the time limit above stated. Other substances, however, canalso be used with entire satisfactiom If one or more of the common water soluble alkalis are dissolved in water and the solution so produced is employed as a releasing liquid, the alkali dissolves the rodn sizing in the paper and thus expedites the releasing operation. As above stated, however, the best materials which I have so far discovered for this purpose are the sulphonated higher alcohols, such as those above mentioned.

By using a sized backing sheet, the dimculties above described can be completely overcome, thus substantially eliminating the errors in registration heretofore occasioned by variations in the dimensions of the sheets due to changes in atmospheric humidity. At the same time the sized sheet is easier to handle in all of the manufacturing operations and is somewhat less expensive thantheunsizedbackingsheets. Also,byusing a releasing liquid of the character above described,thedecalcomaniasmadeonthiskindof paper can be applied to'the work fully as rapidly as those produced by the old method.

'rnc sinsle flsure of the accompanrins drawing illustrates, somewhat diagrammatically. a decalcomania sheet embodying this invention, thebackingsheetbeingindicatedat l andthe tlwvzldecalcomaniacoatingsatiandlrespecwhilelhavehereindescribedtypical embodiments of my invention and a preferred method of procedure, it will be understood that minor variations may be made without departing from the spirit or scope of the invention.

Having thus described my invention, what I desire to claim as'new is:

LAdecaIcomaniapapercomprisingabacking sheet of paper sized suiilciently to give it a substantial degree of resistance to moisture and having a surface coating adapted to be printed upon, said coating having a water soluble adhesive union with said backing sheet.

2. A decalcomania paper comprising a backingsheetofrosinsizedpapeaacoatinghavins a surface adapted to be printed upon, and a layer of an adhesive, readily soluble in water, bonding said coating to the face of said sheet, said coating 'being of different composition from that of said adhesive.

3. A decalcomania paper comprising a water permeable backing sheet of paper containing a sufficient quantity of awater resistant sizing to render the paper substantially unaffected in dimensions by wide changes in atmospheric humidity, and a surface coating on said paper adapted to take decalcomania printing, said coating having a water soluble adhesive union with said backing sheet.

4. The herein described method of using a decalcomania having a backing sheet sized to make it stable in dimensions under wide changes in atmospheric humidity and including a water soluble coating by means of which the decalcomania design is bonded to said backing sheet, comprising the steps of applying said decalcomania to an article of work, releasing said sheet from the decalcomania design by wetting the backing sheet with water and promoting the penetration of the water into and through said backing sheet by including in the water a substance which substantially reduces its surface tension.

5. The herein described method of using a decalcomania having a backing sheet sized to make it stable in dimensions under wide changes in atmospheric humidity and including a water soluble coating by means of which the decalcomania designisbondedtosaldbackingsheet, comprising the steps of applying said decalcomania to an article of work, releasing said sheet from the decalcomania design by wetting the backing sheet with water, and causing the water to penetrate said sheet at a rate substantialLv faster than that due simply to the capillary attraction of the sheet for water.

6. The herein described method of using a decalcomaniahavingabackingsheetsiredtomake it stable in dimensions under wide changes in atmospheric humidity and including a water soL uble coating by means of which the decalcomania design is bonded to said backing sh t, -1 ing the steps of apply l said decalcomania to an article of work, and releasing said sheet from the decalcomania printing by wetting the backing sheet with water and at substantially the same time actingchemicallyonthe sizinginthebackins sheet to soften it.

y 7. 'lhehereindescribedmethodofusingadecalcomania having a backing sheet containing a sumciqnt pr portion of a water resistant sizing to make it stable in dimensions under wide changes in atmospheric humidity and including a water soluble coating by means of which the decalcomania design is bonded to said backing 7 sheet, comprising the steps of app y m said decaicomania to an article of work, releasing said sheet from the decaicomania design by wetting the backing sheet with water, and augmenting said releasing action by including in the water a substance adapted to dissolve the sizing in said

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