US2268595A - Printing ink - Google Patents

Description

Patented Jan. 6, 1942 PRINTING INK Walter Huber, Mount Kisco, N. Y., Frank G.

Breyer, Wilton, Conn., and Lothian M. Burgess,

St. Albans,-N. Y., assignors to J. M. Huber Ina,

New York, N. Y., a corporation of New Jersey No Drawing. Application September 20, 1939, Serial No. 295,752

19 Claims.

This invention relates to new printing ink compositions.

In conventional letter-press printing processes,

wet films of liquid ink are printed onto a sheet or web at ordinary-temperatures, and the print is dried or set before folding r stacking the printed matter or making another printed impression thereon. The drying or setting of the wet print is effected either by oxidation or polymerization of an oily constituent of the ink vehicle, or by evaporation of volatile solvents or carriers from the ink, or by absorption of the ink into the paper, or by a combination of these. Newspaper inks consist of pigment dispersed in non-drying mineral oils, which are sometimes thickened with resins or vegetable oils. When printed onto absorbent news stock the liquid constituents of the ink penetrate into the interstices of the paper by capillary attraction, and the pigment is thus fixed on the fibres of the paper. Since the pigment is not bound securely and the ink never becomes really solid there is a tendency for the print to smear badly. Smearing or smudging occurs frequently during passage of the printed web over angle bars and folders of the press, and serious troubles often are caused by off-setting of the print onto. the impression roller or tympan of the press when making a second impression and onto other printed matter when sheets cut from the printed web are folded and stacked. The printed matter itself has an inferior appearance, and smudging and off-setting of the print when handled by the reader are objectionable. I

Printing inks which dry by oxidation are used to some extent in printing work of higher quality than newspaper printing, but the delays, expense and operating difficulties incident to the printing of such inks restrict their practical utility to relatively slow speed printing. For high speed printing work of higher quality than newspaper printing the combination of the principles of absorption and oxidation has been used quite generally.

In recent years inks have been employed for rotary letter-press printing on comparatively non-absorbent paper stock, as in the printing oi magazines, which consist of pigments in adminture'witn binders thinned with solvents that are volatile at comparatively high temperatures.

when using these inks the web must be heated length of the web between impressions of as high as 30 to 60 feet more than the normal lead. Registration troubles are encountered in multipIe-impression printing work because of the length of the web between impressions and dimensional changes in the paper which result from the heating and cooling operations.

*Printing inks which are dried by intense heating and volatilization of solvents also create fire and health hazards, and an excessive amount of the printed stock is damaged, often amounting to more than 10%.

These printing inks have the further disadvantages that they tend to harden or dry on the printing press, and their working, printing and drying qualities are not uniform but vary with the type and speed of the press, the nature of the medium being printed on and the weather conditions in the press room. These variations require frequent adjustments of the ink for mulae, yet precise control over the qualities of the ink is unattainable.

In contrast to the conventional printing processes mentioned hereinabove, a new process of printing has recently been developed in which letter-press printing operations are carried out by heating to an elevated temperature an ink that is solid and rigid at ordinary temperatures and that melts to a fluid consistency suitable for printing at elevated temperatures, applying the molten ink to heated relief surfaces of a printing form and printing hot fluid films of the molten ink from the printing surfaces onto a relatively cool sheet or web in films so thin that the print sets instantaneously upon leaving the printing surfaces by freezing due to loss of heat therefrom into the sheet or web and the surrounding atmosphere. By cooling the printed films of ink immediately after they have been printed a frozen, completely solidified print is produced which is rigid and resistant to smearing, marring and od-settlng during succeedinp, impressions and during the folding, stacking and assembling of the printed matter, even though the press be operated at very high speeds. Further features and advantages oi said process are set forth in a copending application of Walter Huber, Serial No. 288,113, filed August 3, 1939.

The principal object of the present invention is to provide new printing inks for use in carrying out the aforesaid process of letter-press printing.

Another object of the invention is to provide printing inks which are rigid, rub-resistant solids at ordinary temperatures and at elevated temperatures become liquids having the proper fluid consistency and body and suitable working and printing qualities for high speed printinu opera tions, as well as for other printing work of var ious types.

Another object of the invention is to provide printing inks which are stable and do not harden or vary in their properties during their use at elevated temperatures on a printing press; also, to provide new inks which have constant consistencies and printing qualities at given temperatures and which are subject to controlled variations in these respects by simple variation of temperatures.

Other features and advantages of the invention will be apparent from the following specification.

The printing inks provided by the present invention consist of silk coloring material, usually pigments, in composition with a normally solid and rigid vehicle. The vehicle of the new inks is composed principally of hard high-meltingpoint material which is rigid and resistant to scufling, rubbing and the like at ordinary atmospheric temperatures. This base material must melt to a liquid form at elevated temperatures and freeze again to a rigid solid condition on cooling to ordinary atmospheric temperatures. It should not be thermo-setting to any substantial degree. In general, the base material for the ink vehicle consists of normally hard natural or synthetic resin which is quite fluid at elevated temperatures above its melting point and substantially free from thermo-setting qualities. In preferred embodiments of this invention the hard thermoplastic resin base material constitutes more than 50%, by weight, of the ink vehicle.

A second component is usually essential in conjunction with this hard resin base material. This second component consists of one or more substances which impart desired fluid qualities to the compounded ink at elevated temperature and improve its working and distributing qualities on the printing press. The liquefying material is non-volatile and does not fume or decompose at the elevated temperatures employed in the printing work. It is sufliciently compatible with the resin both when the resin is molten and when it is solid, so that these components of the ink do not separate in the use of the ink on a printing press, nor after the ink has been printed. The liquefying agent may include va material having a solvent action on the resin base material. It is added to the vehicle in minor proportions such that the compounded ink is assured of satisfactory rigidity and rub-resistance at ordinary temperatures, even though the liqueiying agent itself be a liquid, while the working qualities of the ink at elevated temperatures above its melting point are materially improved by the addition.

A third component is usually included in the vehicle to modify the objectionable tackiness otherwise encountered when the printed ink is frozen. At elevated temperatures above the melting point of the resin base this tack-modifying agent should be highly fluid. At ordinary temperatures it should impart the desired nontackiness to the frozen ink when used in the vehicle in suitable proportions. In the preferred inks of this invention a small amount of hard wax serves as the tack-modifying agent in the ink vehicle. The content of wax in the vehicle of an ink for high speed rotary letter-press printing is generally kept below 20%, and in some cases we find it preferable that the wax content of the vehicle be not more than about Substantially higher amounts of wax may keep the ink from working and distributing properly on the printing press by producing an objectionable greasiness in the molten ink. Higher amounts of wax also may be unsuitable because of a crayon-like consistency and low rub-resistance which they may impart to the solid printed ink.

In compounding the inks of the present invention, various ink coloring materials of the types used in ordinary printing inks may be employed. The pigment for black thermo-fluid inks usually consists of carbon black, with or without toning pigments or dyes of other colors. In making a red ink lithol red may be used, and chrome yellow is a suitable pigment for a yellow ink. The vehicles of the new thermo-fluid inks permit the inks to be compounded with pigments of various colors and types to attain unlimited variations in their color qualities.

The thermo-fluid printing inks compounded of ink coloring material and normally solid and rigid vehicles according to the present invention are rigid rub-resistant solids at ordinary temperatures, and at elevated temperatures above their melting ranges they become fluid and assume consistencies suitable for printing from a properly heated printing press. In general, the inks melt in a range of temperatures lying above F. At elevated printing temperatures above F. they are quite fluid; yet they are not watery but have a body which, for example, is capable of holding fluid films of the ink to heated relief surfaces of a letter-press printing form while the form is movingat high speeds. Their internal cohesion, however, permits instantaneous and sharp transference of the ink films from the form to paper or the like when printed. The inks are non-volatile and they do not fume, harden or decompose at the elevated temperatures encountered in their use on a suitably heated printing press. Each ink has a substantially definite fluidity at any given elevated temperature above its melting range, and its fluidity may be varied by simple variation of temperature.

In compounding the vehicles for the printing ink-s of the present invention, we preferably use as the base material of the vehicle a resin which is quite hard at ordinary temperatures and which becomes fluid, as distinguished from merely plastic, at elevated temperatures above its melting range. Certain hard cumarone resins are particularly useful resin materials of this type. These include the para-cumarone-indene resins, which are known commercially as Cumar" and Neville" resins. These resins are neutral, water-proof and non-volatile. They are not thermo-setting. When molten they are quite fluid.

Other useful resins, because of their fluidity when molten and their availability and economy, are hardened rosins and rosin derivatives, for example, hydrogenated rosin, esters made therefrom, oxidized rosin, limed rosin, rosin maleates, ester gum and ,Vinsol rosin, a rosin derivative from long leaf pine made by the Hercules Powder Company.

In conjunction with or as substitutes in part for the above named resins, other resins or p'itches may be employed to modify the ink vehicle. A useful resin for this purpose is gilsonite, a natural bituminous resin. Gilsonite is somewhat viscous, long" or stringy when molten, and when included in the thermo-fluid inks of the present invention it imparts body or length to the ink, which is sometimes desirable.

To add hardness to the ink certain phenolic resins may be used, particularly phenol-aldehyde resins melting at temperatures between 125 F. and 300 F. These resins are known commercially as Bakelites Amberole and Beckecites. If therrho-plastic they may be used in the vehicle in minor proportions, but not more than a small percentage of thermo-settlng phenolic resin should beused since the final ink vehicle, however modified, must be stable on the printing press and must not set under the heating conditions to which it is subjected Prior to being printed.

Certain thermo-plastic alkyd resins may be used as modifying constituents of the ink vehicle. These resins vary in melting point from very hard materials which add hardness and toughness to the ink to comparatively soft materials which may be used for their liquefying effect on the molten ink and their adhesive quality. Hardness qualities of the vehicle .may be promoted also by the inclusion of a natural resin, such as dammar, or a fossil resin, such as Kauri.

The liquefying material preferably used with a hard resin base material is a non-volatile oil having a solvent action on the resin base, with or without other non-solvent liquefying material which will reduce the tendency of a solvent to cause objectionable tackiness in the molten ink. Heavy vegetable oils are particularly suitable; for example, blown soya bean oil and heavybodied China wood oil. Soft or liquid resins, such as certain alkyd resins or rosin esters, or heavy mineral oils, fatty acids, rosin oils, pitches and coal tar oils may be used in small proportions as liquefying agents in some embodiments of the invention. Generally speaking, when a non-volatile liquid is used as the liquefying agent, the content of such material in the ink vehicle should be less than 30% by weight. The amount of liquefying material in every case is insuflicient to destroy the rigid solid form of the thermo-fiuid ink at ordinary temperatures, but is suificient to enhance the desired fluidity, working qualities and distributing qualities of the molten ink at elevated printing temperatures.

The tack-reducing component of the ink vehicle, as before stated, preferably consists of hard wax in an amount not exceeding 20% of the weight of the vehicle, and preferably less than Hard paraffin wax, carnauba wax, candelilla wax, and Montan wax are useful materials by reason of their hardness at atmospheric temperatures and their freedom from tackiness. According to a special feature of preferred embodiments of the invention, wax and resin materials are used which are compatible with each other and do not separate when the ink is molten, but are incompatible to a substantial degree when the ink is solid. When using a composition of this type, a small amount of wax sweats or blooms from the other constituents of the ink as the printed ink solidifies in thin films on the paper, and a thin slippery coating of hard wax is produced over the surface of the print which makes the print quite resistant to marring and rubbing. The hard slippery thin film on the print reduces the danger of oil-setting, and the printed sheets are prevented from sticking together. Notwithstanding the blooming action of the wax during the solidification of the printed ink, however, the wax iscompatible and remains in homogeneous composition with the other constituents when the ink is molten, and it does not separate to any substantial extent when large masses or blocks of the ink are cooled from a liquid to a solid condition.

The wax content. by reason of its water-like fluidity at elevated temperatures above its melting point, acts also as a liqueiying agent for the hard resin base. When employing a comparatively largewax content, up to about 20%, the amount of other liquefying material may be reduced below that desired when using the preferred amounts oi wax.

The following illustrative examples represent useful thermo-fluid printing inks which have been compounded in accordance with the present inventlon:

I. Black printing ink Constituents: Parts by weight Cumar resin (V) 56 Blown soya bean oil 20 Carnauba wax 10 Carbon black 10 Violet toner 2 Blue toner 2 Melting range, l36-145 F.

II. Black printing ink Constituents: Parts by weight Hydrogenated rosin ester gum (Staybelite ester gum) 68 High melting parafllne (160 F.) 12

Carbon black '16 Toners 4 Melting range, F. F.

III. Black printing ink Constituents: Parts by weight Rosin (N wood rosin) 62 Carnauba wax 18 Carbon black l6 Toner 4 100 Melting range, -178 F.

IV. Black printing ink Melting range, 154-l60 F.

V. Red printing ink Parts by weight Cumar resin (V) Heavy-bodied China-wood oil (viscosity,

30-35 poises) 20 Carnauba wax 5 Lithol red 10 Melting range, 162176 F.

VI. Yellow pTinting ink Gonstituents: Parts by weight Cumar resin (V) 47 Heavy-bodied China-wood oil (viscosity, 30-35 poises) 15.5 Carnauba wax 7.5 Chrome yellow 30 Melting range, 167-176 F.

The melting ranges of the inks of the foregoing examples were determined by means of a Parr bar.

The inks of the examples are particularly suitable for use in carrying out the new process of letter-press printing described in the aforesaid application of Walter Huber. In rotary letterpress printing operations according to said process (for example, at web speeds in excess of 300 feet per minute) the inks of Examples I to IV and VI may be printed satisfactorily at printing surface temperatures of about 190 F. and above; the ink of Example V, at printing temperatures of about 205 F. and above. These temperatures may be varied under different printing conditions to obtain different printing qualities in the molten inks, for example, at higher printing speeds the inks may be printed at higher temperatures; or at low speeds lower temperatures may be used.

Printing inks embodying the present invention are particularly useful for letter-press printing work, but may also be used for printing by gravure or planographic processes, using suitably heated printing apparatus. The new inks may be used for various types of commercial printing work, including single and multiple impression printing and multi-color work, and they may be printed on various kinds of sheet or Web stock in addition to ordinary newsprint, book and magazine paper.

In the use of the new inks for letter-press printing they are heated and melted and then placed in a heated fountain of the printing press, or they are placed in the fountain in their normal solid form and allowed to melt therein. The ink transferring and distributing rollers of the press are heated to suitable working temperatures above the melting range of the ink, and the printing surfaces of the printing form are heated to printing temperatures at which molten films of the ink thereon have the proper fluidity and printing qualities for the speed of the press and the type of stock being printed. Thereupon, the hot molten ink is fed from the ink fountain across the feeding and distributing rollers and onto the printing form, and hot fluid films of the ink are printed from the printing surface onto a relatively cool sheet or web in films so thin that the print sets and becomes case-hardened instantaneously upon leaving the printing surfaces. Further cooling of the printed ink, either naturally or with the aid of artificial cooling in high speed work, produces a solid print immediately after the ink has been printed which is resistant to smearing, rubbing and off-setting during any succeeding impressions and during the folding, stacking, assembling and subsequent handling of the printed matter.

The new thermo-fiuid printing inks distribute well on the printing press, and they are free from greasiness which would cause the composition rollers of the press to slip and drag. They do not fume or decompose or vary in their composition while in use on the press. There is no drying or volatilization of solvents to contend with. The hot fluid ink adheres evenly to the heated printing surfaces of the form at high printing speeds, yet it exhibits a tack or pull toward the relatively cool paper, when contacted therewith, which results in exceptionally sharp and clean printing. The inking surfaces of the press therefore do not become as dirty or require as frequent wash-ups as they do in the case of ordinary printing inks.

Th finished print obtained from letter-press operations with the present inks consists of sharp characters having quite regular edges as viewed under a microscope. The print does not spread or penetrate into the fibres of the paper, but it adheres to the top surface of the top fibres of the matte. In general appearance, even when printed on soft porous stock, it is much like the print produced with known printing inks in printing work of very high quality on coated paper. The printed ink remains hard and resistant to smearing and off-setting under all weather conditions to which it is ordinarily sub ject in the use of the printed matter.

It will be understood that the particular constituents and proportions to be used in compounding inks within the purview of the present invention are susceptible to rather wide variation, and that the invention is not restricted to such details except as may be required by a fair interpretation of the appended claims.

We claim:

1. A printing ink for book-, newspaper-, magazineor similar commercial printing consisting of printing ink coloring material incorporated in a solid thermo-fiuid vehicle more than 50% by weight of which consists of hard thermoplastic resin and the remainder of which includes a substantial proportion of organic plasticizing material having a liquefying effect on said resin when the ink is molten, said ink being solid, rigid and smudge-resistant at ordinary temperatures, melting when heated, having a fluid consistency suitable for printing at elevated temperatures substantially above its melting temperature, and being stable against volatilization and chemical change in use at said elevated temperatures.

2. A printing ink for book-, newspaper-, magazine-or similar commercial printing consisting of printing ink coloring material incorporated in a solid thermo-fiuid vehicle more than I 50% by weight of which consists of hard highmelting-point resin and the remainder of which includes a substantial proportion of organic plasticizing material having a liquefying effect on said resin when the ink is molten, said material having a solvent action on said resin, said ink being solid and rigid at ordinary temperatures, melting when heating, having a fluid consistency suitable for printing at elevated temperatures substantially above its melting temperature, and being stable against volatilization and chemical change in use at said elevated temperatures.

3. A printing ink for book-, newspaper-, mag azineor similar commercial printing consisting of printing ink coloring material incorporated in a solid thermo-fluid vehicle more than 50% by weight of which consists of hard thermoplastic resin and the remainder of which includes a substantial proportion of non-volatile vegetable oil, said ink being solid and rigid at ordinary temperatures, melting when heating having a fluid consistency suitable for printing at elevated 2,aos,ues

temperatures substantially above its melting temperature, and being stable against volatiiization and chemical change in use at said elevated temperatures.

4. A printing ink for book-, newspa'per-, magazineor similar commercial printing consisting of-printing ink coloring material incorporated in a solid thermo-fluid vehicle more than 50% by weight of which consists of hard thermoplastic resin and the remainder of which includes a substantial proportion of organic plasticizing material having a liquefying effect on said resin when the ink is molten and a substantial proportion of waxy material which is watery when molten and hard and non-tacky at ordinary temperatures, said ink being solid, rigid and smudgeresistant at ordinary temperatures, melting when heated, having a fluid consistency suitable for printing at elevated temperatures substantially above its melting temperature, and being stable against volatilization and chemical change in use at said elevated temperatures.

5. A printing ink for book-, newspaper-, magazineor similar commercial printing composed of printing ink coloring material incorporated in a solid thermo-fluid vehicle consisting substantially entirely of more than 50% by weight of hard thermo-plastic resin, a substantial proportion oi. non-volatile organic plasticizing material having a liquefying efl'ect on said resin when the ink is molten and a substantial proportion of l-trd wax, said ink being solid, rigid and smudge-resistant at ordinary temperatures, melting when heated, and having a fluid consistency suitable for printing at elevated temperatures substantially above its melting temperature.

6. A printing ink for book-, newspaper-, magazineor similar commercial printing composed of printing ink coloring material incorporated in a solid thermo-fluid vehicle consisting substantially entirely of more than 50% by weight of hard-thermoplastic resin, non-volatile oil in a substantial proportion of less than 30% by weight, and hard wax in a substantial proportion not exceeding about 20% by weight, said ink being solid, rigid and substantially non-tacky at ordinary temperatures, melting in a range of temperatures above 125 F. and having a fluid consistency suitable for printing at elevated temperatures substantially above its melting temperature.

7. A printing ink for book-, newspaper-, magazineor similar commercial printing consisting of printing ink coloring material incorporated in a solid thermo-tluid vehicle more than 50% by weight of which consists of hard thermo-plastic resin and the remainder of which includes a substantial proportion but not more than about 20% by weight of hard wax, said ink being solid, rigid and substantially non-tacky at ordinary temperatures, melting in a range of temperatures above 125 F., having a fluid consistency suitable for high speed letter-press printing only at elevated temperatures above 190 F. and being stable against volatilization and chemical change in use at said elevated temperatures.

8. A printing ink for book-, newspaper-, magazineor similar commercial printing consisting of printing ink coloring material incorporated in a solid thermo-fluid vehicle more than 50% by weight of which consists of hard thermo-plastic resin including principally such resin from the group consisting oi cumarone resins and hard rosins and rosin derivatives, and the remainder of which includes a substantial proportion of on ganic plasticizing material having a liquefying eiiect on said resin when the ink is molten and a substantial proportion of waxy material which is watery when molten and hard and non-tacky at ordinary temperatures, said ink being solid, rigid and smudge-resistant at ordinary temperatures, melting in a range of temperatures above 125 F., having a fluid consistency suitable for printing at elevated temperatures substantially above its melting range and being stable against volatilization and chemical change in use at said elevated temperatures.

9. A printing ink for book, newspaper-, magazineor similar commercial printing consisting of printing ink coloring material incorporated in a solid thermo-fluid vehicle more than by weight of which consists of hard thermo-plastic resin, including a substantial proportion 01' gilsonite and resin from the group consisting of cumarone resins and hard rosins and rosin derivtives, and the remainder of which includes a substantial proportion of hard waxy material, said ink being solid, rigid and smudge-resistant at ordinary temperatures, melting when heated, and having a fluid consistency suitable for printing at elevated temperatures substantially above its melting temperature.

10. A printing ink for book-, newspaper-, magazineor similar commercial printing consisting of printing ink coloring material incorporated in a solid thermo-fluid vehicle comprising a substantial proportion but less than 30% by weight of non-volatile oil, a substantial proportion but not more than about 20% by weight of hard wan material and substantially all of the remainder hard thermo-plastic resin including principally such resin from the group consisting of cumarone resins and hard rosins and rosin derivatives, said ink being solid, rigid and smudge-resistant at ordinary temperatures, melting when heated, and having a fluid consistency suitable for printing at elevated temperatures substantially above its melting temperature.

11, A printing ink for book-, newspaper-, magazineor similar commercial printing comprising coloring pigment incorporated in a solid thermofluid vehicle comprising a substantial proportion but less than 30% by weight of non-volatile, nondrying vegetable oil, not more than about 10% by weight of hard wax and substantially all of the remainder hard thermo-plastic resin including principally cumarone resin, said ink being solid, rigid and smudge-resistant at ordinary temperatures, melting in a range of temperatures above F. and having a fluid consistency suitable for high speed letter-press printing at elevated temperatures above F.

12. A black printing ink for book-, newspaper-, magazineor similar commercial printing comprising black carbon pigment incorporated in a solid thermo-fluid vehicle comprising a substantial proportionbut less than 30% by weight of non-volatile, non-drying oil, a substantial proportion but not more than about 20% by weight of hard waxy material and substantially all of the remainder hard thermo-plastic resin including gilsonite and resin from the group consisting of cumarone resins, rosins and rosin derivatives. said ink being solid, rigid and smudge-resistant at ordinary temperatures, melting when heated and having a fluid consistency suitable for high speed letter-press printing at elevated temperatures above 190 F.

1-3. A printing ink for book-, newspaper-, magazineor similar commercial printing consisting of printing ink coloring material incorporated in a solid thermo-fluid vehicle more than 50% by v weight of which consists of hydrogenated rosin ester gum and the remainder of which includes a substantial proportion but not more than about 20% by weight of hard wax. said ink being solid, rigid and smudge-resistant at ordinary temperatures, melting in a range of temperatures above 4 125 F., having a fluid consistency suitable for printing at elevated temperatures substantially above its melting range and being stable against voiatilization and chemical change in use at said elevated temperatures.

14. A printing ink as described in claim '7, said resin comprising principally resin -from the group consisting of hard thermo-plastic cumarone resins. resins and rosin derivatives.

coloring material incorporated in a solid thermofluid vehicle composed substantially entirely of hard thermo-piastic resin as the principal ingredient together with substantial but smaller proportions oi! non-volatile oil and solid waxy material. r

17. A normally solid printing ink comprising coloring matter incorporated in a thermo-fluid vehicle more than 50% by weight of which is hard thermo-plastic resin and the remainder of which includes a substantial proportion of hard waxy material, said resin being mainly from the group consisting of hard thermo-plastic cumarones, rosins and rosin derivatives and including a substantial proportion of gilsonite.

18. A normally solid printing ink comprising coloring matter incorporated in a thermo-iiuid vehicle more than 50% by weight of which is hard thermo-plastic resin and the remainder of which includes a substantial proportion of hard waxy material, said resin being mainly from the group consisting of hard thermo-plastic cumarones, rosins and rosin derivatives and including a substantial proportion of phenolic resin.

19. A normally solid printing ink comprising coloring matter incorporated in a thermo-fluid vehicle more than 50% by weight of which is hand thermo-plastic resin and the remainder of which includes a substantial proportion of hard waxy material, said resin being mainly from the group consisting or hard thermo-plastic cumarones, rosins and rosin derivatives and including a substantial proportion of alkyd resin.

WALTER HUBER. FRANK G. BREYER. LOTHIAN M. BURGESS.

CERTIFICATE OF CORRECTION.

'Patent No. 2,268,595. January 6,-19h2.

WALTER HUBER, ET' AL It is hereby certified that error appears in the printed specificationoi the above numbered patent requiring correcti on as follows: Page 2, first column, line 11, for "silk" read -ink--; page 14., second column, line 61,

claim 2, and line 7b., claim 5, for "heating" read --heated-'-; page 5, secand column line 50, claim 11, after o iI,'f insert --a substantial'proportion but; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the- Patent Office.

Signed and sealed. this 5rd day of March, A. D. 19142.

Henry Van Arsdale, (Seal) I Acting Commissioner of Patents.