US2579044A - Methods of embossing film and coatings produced from heat curable elastomers - Google Patents

Description

Dec. 18, 1951 a s w KOBER 2,579,044

METHOD OF EMBdSSI NG FILM AND COATINGS PRODUCED FROM HEAT CURABLE ELASTOMERS Filed July 16, 1949 '6 A A 4 P I r '1 7 I A: {O

INVENTOJR.

54 L W. K0858 BY HTT KNEX iatentecl Dec. 18, 1951 METHODS OF EMBOSSING FILM AND ooA'rmos PRODUCED mom HEAT CURABLE ELASTOMERS Saul W. Kober, Flushing, N. Y. a Application July is, 1948, Serial No. 39,166

V This invention deals with embossing, par ticularly embossing of regular patterns, designs, characters or the like and more particularly embossing of such matter on films and coatings produced from compounds of heat curable elastomers, such as organosols, plastisols and the like, either as plain or decorated unsupported film or as a coating on a plain or printed base. In the previous art of embossing regular patterns, characters, images and the like, devious ways have been used to obtain raised eifects on these materials. In all instances dies of various sorts were use. These took the form of dies engraved in intaglio or in relief. These dies were often used with an opposing male or female part called a counter and between which the material was passed or laid in order to obtain the embossing by means of heat and pressure.

These dies were in the form of rollers when embossing was desired to be done on a continuous web or they were in the flat form when embossing was to be done on single sheets. Embossing of these materials was also accomplished by means of casting the heat curable In all cases of the above described methods,

expensive dies were used and very heavy and expensive machinery was necessary to operate or run such dies.

Those versed in the art know that considerable difficulty is encountered in the process of embossing multi-color printing in the web form because of the necessity for close registry. The difliculty becomes practically insurmountable when the multi-color printing is first coated before embossing.

Especially is this the case when the coating is relatively thick, requiring a considerable time for drying or setting before embossing. This is true of single sheets as well as in the web form.

It is a primary object of this invention to provide a method for embossing regular patterns, designs and characters on film and coatings produced from heat curable elastomers, such as organosols, plastisols, and the like without the use of embossing dies.

It is another object of this invention to provide a method for embossing regular patterns,

designs and characters on film and coatings produced from heat curable elastomers, such as dry andalso while in the wet state.

portion with the printed image.

1 Claim. (Cl. 111-15) organosols, plastisols, and the like without the use of heavy and expensive embossing equipment. i a It is another object of this invention to produce embossings of predetermined designs and characters as for example; Braille characters on curedelastomers, such as organosols or plastisols by employing the conventional printing processes and using an ink suitable to such process, such ink being especially prepared and having gas evolving propertiesat a temperature range below the curing temperature of the heat curable elastomers, such as organosol or plastisol but not below the initial setof such coatings, the ink having further properties to produce embossings of exceptional fidelity to their printed images, and a well rounded and pleasing feel and appearance.

It is a further object of this invention to provide a method of embossing on these materials which simultaneously incorporates at least one color on the embossing;

It is a further object of this invention to provide a method of embossing multi-color printed unsupported film and multi-color printed and coated material, such as paper and the like,'in register without the critical control necessary for such registry.

Other objects will become apparent upon reading ofthe descriptive specifications and the appended'claim.

To carry out such objects I tried printing regular designs and type faces upon a base, such as paper, with inks containing various substances that would expand or otherwise release gases of various sorts when heated and I tried coating this printing with a layer of organosol or plastisol and subjecting the printed and coated base of theprinted part on the cured coating, but

the results were not entirely satisfactory.

I tried using oil base inks containing drying oils such as bodied linseed and having ground into this ink various proportions of ammonium or sodium bicarbonate or both as leavening agents. Printed "specimens using this type of ink were coated after such ink was allowed to In both cases the coating was raised or embossed but the embossing on the dried print was full of pinholes, was of unsatisfactory height and showed general lack of smoothness. The embossing on the wet specimen was higherand showed more promise of smoothness but under the influence of heat, the oil vehicle spread, causing the embossing to spread out of pro- Further, it I found that oil base inks generally had too much aflinity for organosol and plastisol coatings unsatisfactory because of variable evaporation, tendencies.

Water base inks having incorporated within leavening agents, were more satisfactory, but

here, too, embossing had rough pock-marked apfpearances because of the uneven action of, the,

leavening agent and also because of sticking of the coating to such ink.

I therefore kept on experimenting and int vented incorporating in;the ink a heat reactive large amount of diethanolamine in order to render: the mixture highly hygroscopic. Corn dextrin was used as the thickener or bodying agent, Such ink proved highly successful becausefit did not run under heat, began evolving gases or vapors at about 212 F.', or about the temperature of initial setof organosol or plastisol coatings, such evolution of gases becoming complete at about 350? F. or the curing" tem perature of such coatings,

Therefore, to carry outmy, proposed objects, one form of my invention provides for printing the lines or characters that are desired to be raised or embossed.v on a. base, such as paper, with an ink as outlined above, coating this printed matter with an organosol or plastisol consisting of a vinyl chloride or vinyl'chloridevinyl acetate 'copolymer resin in a plasticizer,

such as a phthalate plasticizerand containing a; stabilizer. Such organosols or plastisols may also contain fillers, pigments, dyes, solvents and diluents, Thev next step provides for heating such printed and coatedbase to a temperature range suflicient to cause evolution of gases or vapors from the ink and sufficient to cause curing of thecoating which isabout 350 F.

This process isdiiferentiatedfrom thoseproc- V esses in which a lea'vening agent is dispersed in a coating or a-compound such as rubber or the like, the whole then heated. Embossing or swelling in irregular fashion isobtained by such processes, but this embossing or swelling does not follow a regular, ore-determined patterntand is really not embossing, at all'but a series of 'air cells more or lesshaphazardly distributed. In my proposed method, there is no dispersion of leavening agent in the coating. itself, but merely in the printed. parts. underneath such, coating. Further, in the present methodembossing is not characterized by a multiple of individual or interconnected air cells but by a single controlled air cell in the same contour as the partsjprinted with the embossing This is madepossible because of the hygroscopic nature oftheembossing ink, 'present ing a surface on the embossing ink which is lubricated, or otherwise made incompatible with the coating above, thus. preventing sticking of or.- ganosol, plastisol or, like coatings to such surface when heatisrapplied forthe purpose ofcuring.

When heat is applied, thecombined gases and vapors released by the-embossing inkwill force the fusing; and curing coating away from the surface of the embossing. ink, suchforceacting as a unit in a clearly, defined. space, following aclearly defined contour;

.C cmp ra ivcl rg yp s. e characters or the like may be embossed in this larger the area to be embossed, the higher the embossing will-bee Ifhis, however, is not critical as these materials under heat soon develop great strength and elasticity even in thin sections. For ordinary sizes and up to such sizes as may be designated by seventy-twol'lZ) point bold type, I prefer to use; a coating thickness of .005.010 inch. For larger sizes I prefer to use a coating thickness of .010-.020 inch; For embossing designs containing bothlarge' and'small areas anintermediate thickness ofabout" .0l0 .015' inch is' pree ferred;

In the accompanying drawing'forming amaterial part of. this disclosure:'

Fig. l is'a perspective view of a base printed with embossing ink according to this invention;

Fig 2 is a perspective. view of apiece of embossed organcsol'on' the base shown in Fig.- 1, in accordance with' this'invention.

Fig. 3 is an enlarged section taken on the line 33 of Fig; l.

Fig. 4 is a sectional view similar'to Fig. 3;'but illustrating a modified form' of the invention;

For a better understandingofthe appearance of large and small embossed areas, referenceis now made to Fig; 1 wherein l0 representsa base sheet of paperimprinted with'embossing ink l2, l3, Hi and I5, ii a coating of organosolon said base, and I2, 53', i4 andi5' embossedsections in said coating which were embossed in accord ance with this invention and drawn to relative heights corresponding with the areas of'the em- 7 bossed matter.

In a preferred form'of this invention the process consists of letter-press or typographically printing a flexible material such as paper with an inkconsisting of the following:

Formula for letter-press embossinginkf Procedure for making; letter-press embossinginlc Gently heat the ammonium and sodium bicarbonatewith the diethanolamine.withstirring 7 until first evolution of bubbles.- 7

Cool and add the phenolic varnish, mix well.

Stirin the water and mix until a well broken precipitate forms. a

Add the corn dextrin and the pigment or dye, as desired, and grind on a three roller, mill. 7

The above mixture produces a paste in a consistency well adapted to letter-'pressprinting.

After printing the, parts desired. to be raised with this embossing; ink, theipaper thus printed is then knife-coated witha plasti sol or. organosol as shown in the formulas. below to a thickness of .005-.010 inch and subjected toa temperature of about 350 F. forpne minute;

There are. many formulations of organosols and palstisols suitable. for knife-spread coating finished film or coating desiredl fBelow are buta few preferred forms: PLssTIsoL #1 Clear 100 parts polyvinyl chloride 6 5'parts dioctyl phthalate 2 parts basic lead carbonate H Mix thoroughly. 1

ORGANOSOL #1 C'Zea r 25.00 parts copolymer vinyl chloride-vinyl acetate 27.00 parts-dioctyl phthalate 1.00 partbasic lead carbonate 3.00-parts xylol j Grind in m. l

' I PLASTISOL #2 White V 34.00parts copolymervinyl chloride-vinyl acetate 43.00 parts dioctyl phthalate 2.00partsbasic carbonate white lead 18100 parts calcium carbonate 050 part stearic acid 2.00 parts titanium dioxide 0.0025 part fast violet oil dye I Grind in 3 roller mill.

ORGANOSOL #2 Black 45.00 parts copolymer vinyl chloride-vinyl acetate 28.00 parts dioctyl phthalate 0.68 part carbon black 1.00 part basic lead carbonate 3.00 parts diisobutyl ketone 14.00 parts toluol 8.82 parts xylol l Grind in pebble mill.

IThe preferred copolymer vinyl chloride-vinyl acetate resins contain upwardsof 85% vinyl chloride. l

The parts printed with the embossing ink release their gases, raising the fusing and curing coating over them in a well-rounded manner which conforms exactly to the contour of those parts, which as stated before, may bein the form of lines orcharacters thus printed with the embossing ink. When the temperature of about 350 F; isre'ached, the coating will be completely cured and the 'embossingwill have reached maximum height. The embossing will remain in this posi tion after cooling and will be permanent.

The embossing inks may or may not contain pigment or dye as coloring matter. They may be of the water or oil types. The water dispersible pigment or water soluble dye is added last. The oil soluble dye or oil pigment is ground into the phenolic varnish and incorporated as shown in the formula for letter-press embossing ink.

While most pigments of the non-water dispersible type may be used and ground into the varnish,

those recommended are the inorganic types such 'as iron blues, chrome yellows, ceramic colors and those pigments of the organic variety as will withstand a temperature of 350 to 375 F. for about 1-2 minutes without appreciably fading. An example of the latter are the phthalocyanine blues andgreens. 1

Addition, of coloring matter to the embossing ink-hasthe effect of imparting color to those .d sisns, cha acte sandthe like Which are raised or embossed by this embossing For.

example: If a water dispersible red pigment is added to the letter-press embossing ink, a design or character printed with this ink, the printed parts coated to a pre-determined thickness with a clear organosol or plastisol as above, the whole then heated to a temperature of 350 F. for about one minute, the design or character will appear embossed in red on a clear, transparent or translucent background. The coloring produced on organosol and plastisol film and coatings by such water dispersible pigments and water soluble dyes are fast and unaffected by after-treatment with water.

For production of multi-color, printed, coated and embossed paper and the like, the design proper is printed with as many colors as desired, using conventional letter-press inks readily found on the market. Those parts desired to be raised are printed in register with the design proper using the letter-press embossing ink. The entire printed matter is then coated with an organosol or plastisol as before and the whole assembly heated up to 350 F. in about one minute.

As in the previous case, the coating over those parts printed with the embossing ink will expand and assume a well-rounded and. embossed appearance. The color or colors in register with the embossing ink will be unaffected and the coating over such color or colors will be unaffected and both will remain fiat against each other and against the base each is on.

It has been found that this process produces a raised efiect on unsupported film and coatings made from organosols and plastisols, etc. which is highly desirable and one which is closely similar to an effect produced by the use of hot'embos'sing dies or by means of casting against molds of various sorts.

This process presents a saving in the making of costly dies or molds and is not only a method of securing greater depth of embossing than is possible by other types of embossing media, but is also a method of securing unerring registry of embossing with multi-color printed matter on the above types of film and coatings. Itis understood that What has been described is but a preferred form of this invention and many variations in procedure are possible. Other hygroscopic amines or hygroscopic components may be used in conjunction with the embossing ink. However, I do not prefer to use glycerine as the hygroscopic component because of the excessive leavening action produced in stored batches of this ink. If circumstances are such that the leavening action of stored batches is not important, then I would say that glycerine is excellent as the hygroscopic component. Likewise, other printing processes may be employed, and

other flexible material other than paper may be I usedfor printing on. Coating, too, may be done by any other method. l The rotogravure process of printing may be employed in my invention for the production of printed, coated and embossed paper and the like in the web form. r

When employing the rotogravure or intaglio method of printing, those parts desired to be raised or embossed are printed with the letterpress embossing ink substantially thinned with Water. Experienced rotogravure pressmen are easily able to judge when an ink reaches suitable consistency to be taken up by an etched rotogravure printing roller. In general, a suitable iotogravure embossing ink is made by diluting and: the: like.

thee-letter pressembossin ink 50+l0.0%;by;weight: witl'rwaterz Theiweb desired to be coated: and .embossedi treatedJsubstantially; as iin the-letter-press-meth- 0611- The parts desired.to;be raised or embossed. are printed with the rotogravure .embossingminki,

V The: web thus printed is. led. to; asknifeecoateltr where-a predetermined thickness ofian-organosoh. plastisol-or the like is applied. The: webthus; printe'dian'd coatedtisnext led toa heating device whicmmayribe. either. of the open or closed. type; As in: the case with. the letter-press-method, this process-1: will; produce blind embossing,.that: is: colorless or colored embossing on a similar; colorless or=colored background; a; single color embossing on :atransparent; translucent or: con-. trasting background and. embossed in register with; multi-colored. figures, designs, characters-1 Asstated before, the rotogravure process achieves these results on; a continuous webior roll rather than on singleisheetsr.

Asrinythe letter-press method also, itis prefer.- red toprint the design proper first. This is done by employing conventional. rotogravure ink',... the.

types. dependingon the choice. of flexible material for. printing; Alldesired colors are printed first, andz'lastly those:parts:desired;to be raisedor. embossed: are printed with. the rotogravure embossing ink.

.-Theirembossing. inkrmay: be used;- to' print on metal foil as 1 well; as paper. Interesting. effects; may be produced on thisztypeof printingbase by 'useof my'inventionr Large; transparent, colored-.oncolorless embossedareas may; be produced throughwhichthe-lightreflection of the; metal I foiliwillshow beneath.

Interesting effects, are obtainedalso by using cellophane: as theprinting: base. Since" cello-.- phane is more or less non-porous, coating; of. this and similar non-porous; surfaces shouldv bedone as soon as possible: after printingwith the em.- bossingink. This is necessary, because. of: the

hygroscopic I nature of the embossing ink and: to'

prevent consequent off-setting.

While. an organosol orplastisol vcoatingcismore highly polished surfaces; Colormaybe-imparted to the intaglio impression. By use of metallic powders as the-coloring medium in-the embossing ink, heavy gauge films: may be produced which resemble artificial leather stamped; orengraved with metallicleaf,

It is recommended that metallic. powders; in this purpose be incorporated in the embossing ink merely by. mixing; The'quantity used" should be about 5'-15%by weight of. the ink used, de-. pending on the: brilliance desired;

In my method it: is also-possible to produce any of theabove describedtypesof embossed film without: intaglio imprint but with: smooth back;

To produce; such embossed filmwith smooth back; .I; follow the procedure as described: below,

H of similar material as thexpartially cured base I0 is then applied inapredetermined thick ness over such partially cured and printed base I 0. The temporary base IS with such composite coating is then. subjected. to a temperature of about 350 F. for one minute or sufiicient; to;- cause release of gases-or,vaporsinthe embossing; ink and sufiicient to cure the coating-J0. and: H as a whole. After coating, the complete film l0, II is stripped from the temporarybase 16. The resulting film In, It will have the printed portion within its walls, the embossing in relief, and smooth back.

Coating of the printed; sheets may be done. reverse rollers coater as. wellas by'knifercoateri Calender coatingalso. may-bezemployed. Galen-1' der coating may be done either. hot; or cold'sbut' heating of the top surface a bankoi infra-red lamps may be employed.

Various other uses may be made-of this type of printed, coated and embossed. matter. The coating acts as a protection for the printed matter underneath and although the, embossing is softand flexible, the natural resiliency and springines oi the coating will give a certainfirmness and permanence to'the' embossed out.- line or part.

Such matter may; be usedfor advertising-men ature in which certain partsmay be wished to be emphasized by means-ofraisedorembossed effects: v

Novel effects may be" produced on: greeting cards by having an embossed transparent1coat= ingover regular printed matter;

Durable, water-proof, relief maps may bepro-. duced cheaply "by mymethodQ One highly novel and unique use to which'this process may be put is intheproduction of" a form of Braille printing.- This-is merely done by printing a sheet of paper with dots of predetermined size, thencoating with an organosol or plastisol, subjecting it to atemperaturesufll-icient to release the gaseous formingsubstances in; the embossing, ink and alsosuflicientto cure the overlying coating. The result will be: quite similar to the Braille printing; as produced today by means of dottedembossing-plates. The new system will have the added advantageof being compressible,thus reducingthe thickness. of the average work produced in Braille. Furthermore, everi'tissue paper may be printed and. embossed in this way, thus obviating the use of heavy paper or cardboard. In the inventor opinion this is one of the bestuses to which this'process may be put. It-is' onein which books,: periodicals; etc. .maybeproduced forthe: blind in: un-:1

limited quantities, thus affording these handlcapped people a means of rehabilitation, instruction and entertainment now of necessity made prohibitive by factors of cost, bulk and production difiiculties.

Another use to which this process may be put is that in decorative papers. Highly resistant and durable wall papers having the desirable embossed effect may be produced. Wall papers of this nature have the added advantage of a washable protective coating which may be in a considerable thickness thus affording ample protection for the printing underneath.

Another use to which this process may be put is in the production of multi-color printed and embossed shower curtains and other forms of unsupported film. The process for the manufacture of this type of printed and embossed in register film consists of printing a metallic carrier with an embossing ink as described, in the form of lines or patterns which are to be the final embossed parts, these parts being printed in register with all other colors desired, then coating with a transparent or translucent composition of plastisol or organosol, running through a heating oven at a temperature suflicient to cause release of the gaseous product in the embossing ink and also suificient to cause curing of the overlying coating, allowing to cool and then stripping the film from the metallic carrier. In the manufacture of multi-color printed and embossed unsupported film, where stripping from a carrier is employed, the printing ink forming the design proper must be of such a nature as to be compatible with the p1astisol of organosol coating over it. Such an ink must have less amnity for the carrier than for the organosol coating. An ink of this nature and suitable for the rotogravure method of printing may consist of a resin such as polystyrene dissolved in a solvent such as xylol and containing a plasticizer and pigment or other coloring matter. Another type of ink may consist of a vinyl-chloride or vinyl chloride-vinyl acetate polymer dissolved in a suitable solvent and containing a plasticizer, pigment or other coloring matter. All of the printed matter except the lines printed with the embossing ink will be transferred to the unsupported film. The em bossing ink will release the gases necessary for embossing their image and part will remain on the metallic carrier as a residue. This residue may easily be washed 01f with water and the metallic carrier may be used over and over again as wanted.

In connection with the production of multicolor printed and embossed in register shower curtains and other unsupported film produced from organosols, plastisols and the like, the silk screen method of printing may be used to advantage, since by this method exceptionally heavy ink films may be squeegeed through the silk screen.

As in the case with the letter-press and rotogravure methods, all desirable colors are printed on a suitable base using conventional silk screen printing inks. Those parts desired to be raised or embossed are printed in register with the design thus printed. This latter printing may be done by the silk screen method also, using the letter-press embossing ink thinned by addition of about 3-10 parts of water to the entire formula.

Coating and heating are carried out as previously. Upon cooling, the printed and embossed 10 in register film or coating may be stripped from its base.

Another practical use of this process can be made by individuals wishing distinctive calling cards, letterhead stationery, mail box names and numbers, signs and posters. For this purpose the embossing ink is made quite fluid by addition of water in order to be used with an ordinary steel pen, quill or small artists brush. Coating of this writing may be done by any smooth piece of wood or iron acting as a knife scraper over a stencil. The entire written-on and coated paper or card is then subjected to heat as previously. This heating may be done in the home oven, raised to a temperature of about 350 F. or over an electric heater where' the individual may observe the progress of embossing and curing and use judgment in regard to the degree to these are to be carried.

While I have illustrated and described the preferred embodiments of my invention, it is to be understood that I do not limit myself to the precise constructions herein disclosed and the right is reserved to all changes and modifications coming Within the scope of the invention as defined in the appended claim.

Having thus described my invention, what I claim as new and desire to secure by United States Letters Patent is:

The method of producing embossed forms on a surface which comprises letter press printing on a paper base with a hydrophilic ink which is composed of 2 /2 parts ammonium bicarbonate, 2 /2 parts sodium bicarbonate, 10 parts diethanolamine, 3 parts oil-modified phenolic varnish, 18 parts dextrin, 6 parts water and pigment, said ink being hygroscopic, allowing inked portion to accumulate atmospheric moisture upon its surface, applying over the printed paper base a layer of vinyl chloride plastisol, said vinyl chloride plastisol being composed of a paste of substantially parts vinyl chloride resin, 65 parts dioctyl phthalate plasticizer and 2 parts basic lead carbonate stabilizer, said plastisol setting at approximately the temperature of water vapor at 212 F., and curing at approximately 350 F., and then subjecting printed and coated paper base to a temperature of 350 F. to cause transformation of accumulated atmospheric moisture upon said ink into gases for embossing said layer of vinyl chloride plastisol while it is setting, said temperature of 350 F. also releasing additional gases from the bicarbonate and holding com-- bined gases under pressure until the vinyl chloride plastisol is cured in order that said vinyl chloride coating is soft and flexible and is embossed with a permanent and resilient facsimile in relief.

SAUL W. KOBER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,436,856 Brenizer et a1 Nov. 28, 1922 1,471,884 Dement Oct. 23, 1923 1,888,672 Howard Nov. 22, 1932 2,018,060 Gautsche Oct. 22, 1935 2,157,410 Heller May 9, 1939 2,230,876 Wysong Feb. 4, 1941 2,335,882 Pingarron Dec. 7, 1943 2,365,705 Jeri Dec. 126, 1944 2,412,592 Maier Dec. 17, 1946

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