claim as our invention: 1. The method of preparing a zinc-calcium resinate in the form of a high inelting point, permanently refusible, clear product capable of formIng a stable, non-gelling solution, which comprises reacting, by fusion, a rosin containing a substantfai aznount of polymer with -a zinc compound selected from the group consisting of the oxide, hydro)dde and carbonate in an amount equivalent to at least 5 % by weight of the rosin of ziric oidde, and with at least 1% bY weight of the rosin of hydrated lime, said reaction being earried out in the presence of a catalyst selected from the groUP consisting of organic acids soluble In rosin at the reacting temperature whose acidity is due to a carboxylic acid radical, organic acids soluble in rosin at the reacting temperature whose acidity is of a phenolic nature, -and salts of said acids capable of reacting with abletic acid to liberate said acids. 2. The method of Preparing a zinc-calcium resinate in the form of a high melting point, permanently refusible, clear product capable of forming a stable, non-gelling solution which coi@aprises reacting, by fusion, a rosincontaining a substantial amount of polymer not in 6xcess of about 7 Y2 %, first with from 2.75 to 3 Y2 % by weight of the rosin of hydrated lime, and then with at least 5% by weight of the rosin of zinc oxide mdd reaction being carried out in the ;;;@.Te 'of, a catalyst selected from the group condaung of orge@nlc acids soluble in rosin at the reacting tema perature whose acidity is due to a carboxylic licid radical, organic acids soluble in rosin at the reacting temperature whose acidity Is of a phenolic nature, and salts of said acids capable of reacting with abietic acid to liberate said acids. 10 3. The method of preparing a 2@nc-calclum resinate in the form of a high raelting point, permanently refusible, clear product capable of forming a stable, non-gelling solution which comprim reacting, by fusion, at from,2001 Ao 3000 C., a ro3in 15 containing a substantial amount of polymer not In excess of about 71/2%, flnt, with froin 2.75% to 3.5% by weight of the rosin of hydrated iime and then with at least 5% but not more than 6%, by weight of the rosin of zinc olide, said re&Won 20 being carried out In the ptesence of a catalyist selected from the group consisting of orgwc acids solubli@ in rosin at the reacting temperature whose acidity is due to a carboxylic acid radical, organic acids soluble in rosin at the reacting tem25 perature whose acidity is of a 'Ph6nolic nature, and salts of said atids capable of reacting with abietic acid to liberate said acids. 4. The method of preparing a zinc-calcium resinate in the form of A high melting point, per30 manently refusible, ei-@ar product capable of form..@ ing a stable, non-gelling solution which comprises reacting, by fusion, a rosin containink a substaritial amount of P61ymer not, In excess of about 71/2% i'lrst with from 2.75 to 3.5% by weight of 33 the rosin of hydrated lime, then with at least 5% but not more than 6% by *eight of the rbsin of zinc oxide, and :ftnally with substantial additional arnounts of hydrated lime insumelent to render the reaction niass too viscous for handling, said reaction being carried,out In the presence of a catalyst selected from the group consisting o-f organic acids soluble In rosin at the reacting temperature whose acidity is due to a carboxylic acid radical, organic acids soluble in rosin at the re" 45 acting temperature whose acidity is of a phenolic nature, and salts capable of reacting with abieti6 ocid to liberate said acids. 5. The method of preparing a zine-calcium resinate in the form of a high melting point, per50 manently refusible, clear product capable of forming a stable, non-gelling solution which CoMprises reacting, by fusion, a rosin containing at least about 71/2 % PolYmer first with at least 5 % but not more than 15 % by weight of the rosin of ribc oxide a@ld then reacting the fusion product with hydrat@d lime, in an amount at least equal to 1% by weight of the rosin but insufficient to ren@er the reaction mass too viscous for hand;tng, said reaction being carried out In the presence of a 60 c8talYst selected from the group consisting of organic acids soluble in rosin at the reacting temperature whose acidity is due to a carboxylic acid radical, organie acids soluble in rosin at the re. acting temperature whose acidity is of a phenolic oS nature, and salts of said acids capable of reacting with abietic acid tO liberate said acids. 6. The niethod of preparing a zinc-calejuin resinate in the form of a high melting Point, permanently refusible, clear product capable of form70 Ing a stable, non-gelling solution, which comprises reacting, by fusion, at from 2001 to 300' C., a rosin containing at least about 7 V2 % polymer with at least 5% by weight of the rosin of zinc oxide and then reacting the fusion product with hydrated 75 lime, in an amount at least equal to I% by weiiht

of the rosin bvt ingiffleient to render the reaction mass too viscous for handling, said reaction being carried out in the presence of a catalyst selected from the group consisting of organic acids soluble in rosin at the reacting temperature whose acidity is due to a carboxylic acid radical, organic acids soluble in rosin at the reacting -temperature whose acidity is of a phenolic nature, and salts of said acids capable of reacting with abletic acid to liberate said acids. 7. A method of preparing a zinc-calcium resinat4@ in the for.mof a Wgh melting point, permanehtly refusible, clear product capable of form-@ ing a stable, nongelling solution which comprises reacting, by fusion, a rosin containing at least about 71/2% polymer first with about 10% by weight of the rosin of zinc oxide and then with hydrated lime, in an amount at least equal to I% by weight of the rosin but insufficient to render the reaction mass too viscous for handling, said reaction being carried out in the presence of a catalyst selected from the group consisting of orgwe acids soiuble in rosin at the reacting temperature whose acidity is due t6 a carboxylic acid radical, organic acids soluble in rosin at the reacting temperature whose acidity is of a phenolic nature, and salts of said acids capable of reacting with abietic acid to hberate said acids 8. The method of preparing a zinc-calcium resinate in the form of a high melting point, permanently refusible, ciear product capable of forming a stable, non-gelling solution which comprises reacting, by fusion, a rosin containing at least about 71/2% polymer first with about 15% by weight of the rosin of zinc oxide and then with hydrated lime, in an amount at least equal to 1% by weight of the rosin but ihsufficient to render 5 the reaction mass too viscous for handling, said reaction being carried out in the presence of a catalyst selected from the group consisting of organic acids soluble in rosin at the reacting temperature whose acidity is due to a carboxylic acid radical, organic acids soluble in rosin at the reacting temperature whose acidity is of a phenolic nature, and salts of said acids capable of reacting with abie.tic acid to liberate said acids. 10 9. The method of preparing a zinc-calcium resinate in the form of a high melting point, permanently refusible, clear product capable of forming a stable, non-gelling solution which comprises reacting by fusion at from 2000 to 3001 C., a rosin 15 containing at least about 71/2% polymer with a zinc compound selected from the group consisting of the oxide, hydroxide and carbonate in an amount equivalent to at least 5% by weight of the rosin of zinc oxide, and with at least 1 % by weight 20 of the rosin of hydrated lime, said reaction being carried out in the presence of acetic acid. 10. A fusion produced, permanently refusible zinc-calcium resinate capable of being dissolved in -a petroleum solvent to form a stable, non25 geIIing solution and containing a substantial amount ranging up to about 7.5% of a rosin polymer together with about 4.6% by weight of combined zinc and at least 1.6% by weight of combined calcium. 30 11. A fusion produced, permanently refusible zinc-calcium resinate capable of forming a stable, non-gelling solution and containing at least about 7.5% by weight of 'a rosin polymer tog6ther with from 3.8, to 10.8 % -by welght of combined zinc and 35 at least 0.5% by weight of combined calcium. ROBERT C. PALMEM EDWIN EDELSIMN.

Patented Apr. it@ 19" 293469993 UNITED STATES PATENT OFFICE 2,346,993 PERMANENTLY REFUSIBLE ZINC-CALCIIUM RESINATE AND METHOD OF PREPAR)ING SAME Robert C. Palmer and Edwin Edelstein, Pensa. cola, M, assignors to Newport IndusWes, Inc., Pensacola, Fi&, a corpomtion of Delaware No Drawing. APPHeation October 7, 1942, Serial No. 461,234 11 Claims. (CL 260-105) This application is a contir@uation-in-part of transparent. The transparency of the resinate the appllcation, Serial No. 297 108, by Robert C. Palmer, Anthony P. Oliver, ana Edwin Edelstein, filed September 29, 1939, and entitled "Resinlike product and process of making the same." This Invention relates to zinc-calcium resinates and to methods of preparing such compounds by fu.qion reactions. By a "fusion reaction" we mean a reaction carried out In a fusion mass consisting principally 10 of the reacting compounds and their reaction products, In distinction from a reaction carried out In a normally liquid solvent medium that can be recoveted after the reacti6n is completed. , The term "resinate" is herein applied gener- 15 ally to include the salts of any of the resin acids, for instance, abietic, pimaric or sapinic acids or Polymers or Isomers thereof. Rosin containing one or more of these resin acids may be reacted as disclosed hereinbelow with a zinc compound 20 and,with a calcium compound to form the corresponding zinc-calcium resin acid salts. As far as we know, zinc-calcium resinates characterized by high zinc content, high calcium content, clarity, permanent refusibility, and capacity 25 for forming stable, non-gemng solutions have heretofore not been prepared. The term "Permanent refusibility," as applied herein to resin-like products, means a capacity for being repeatedly fused and solidified, with- 30 out any change in the characteristic appearance of the products, provided that the temperatures to 'which the Products are subjected are kept below those temperatures at which substantial decomposlt lon occurs. 35 By "stable, non-gelling solutions" we mean solutions of resin-like Products In petroleum solvents and the like that do not gel when the solutions are heated to any temperatures short of their boiiing points. 'By "gelling" we signify a 10 thickening of EL flowable solution by heating while a substantially: constant COncentration of solids Is maintained therein, the solution flnally becom-, ing,, in some cases, almost non-flowing at room temperatur e, and sometimes accompanied by the 45 appearanc e of Insoluble matter or precipitate. By the term "clarity" as applied to our products we mean a transparency of the resinate Itself due t6 a substantially complete absence of any unreacted zinc oxide, hydrated lime, or other 50 zine,or calcium compounds used in preparing the resin-like products to which this invention per- , tain8. Such unreacted zin6 and lime compounds, if present, would, of course, tend to render the resin-like product obtained opaque rather than 55 itself Is an Important characteristic of our product, even though for some purposes opacifying agents may be incorpomted therein. In referring to resinates having a high zinc and a high calcium content, we do not mean to limit ourselve's to basic or even to neutral zinecalcium resinates but to include sughtly acid zinc-calcium resinates. When the neutral, acid or basic cha racter of a zinc oiddehydrated limerosin reaction product is referred to, thedesignated character of the reaction product as a whole is meant. Wbis is done to avoid controversy over whether the zinc-calcium resinate itself may not be present In the reaction product as a basic zinc-calcium resinate even wheii the reaction product as a whole has an acid or neutral character. one reason why those sklued in the art heretofore have not been able to prepare clear, permane@tly refusible zinc-calcium resinates having a high zinc and calcium content and capable of forming stable, non-gelling solutioiis Is the fact that ordinary rosin reacts only wit'n difficulty, if et all, with zinc oxide and with hydrated lime and the like at temperatures f&Uing below the decomposition temperature of the rosin. The reaction, even If Initiated, does not go to completion but ceases long before a calculated neutrality has been effected. The acid zinc-calcium resinates of the prior art containing relatively smau amounts of combined zinc and calcium are PIso characterized by Infusibility and by the instability of thelr solutions In petroleum solvents. We have found that the fusion reaction between rosin containing material and zinc oxide, hydrated lime, and the like can be carried so far as to produce even basic resinates If a suitable acid catalyst such as a low molecular weight fatty aeld is lncorpc)rated with the fuslon mass. We have further found that the polymer content of the rosin containing material used for preparing the novel calcium-zinc resinates of this invention is a critical factor in preparing slightly acid, neutral or basic resin-like products characterized by clarity, permanent refusibirty, and abiuty to form stable, non-ge]Iing solutions, combined with relatively high contents of combined calcium and of combined zinc. Thus, if the rosin used as starting material contains less than about 71/2% of a polymer such as the dimer, hydrated lime or the Ijke should be reacted *Ith the rosin used as starting material, before zinc oxide or the like is reacted with the rosin, or else a suf-

2 29840,993 ocimt amount of calcium resinate anould first be, tncorpomted with the rosin. If this order of reaction or addition Is not adhered to, the products obtained are not clear, permaaenuy refuzible and capable of forming 5 stable. non-gering solutions. If the rosin used as a starting material contains more than about 7 V2 % of polymer, zinc oxide or the like shotid preferably, but not neee&sarfly, first be reacted with the rosin before 10 hydrated lime or the Uke is reacted therewith. The polymer content of about 71/2% indicated In the preceding paragraphs is necessarily only an approximation to the actual value of the critical polymer content. The only method available: 15 for an estimation of the polymer content of a rosin is a molecular weight determination. A molecular weight determination can serve as a basis for the calculation of the polymer content of a rosin only when the riormal molecular weight 20 of the unliolymerizbd rosin fraction is known. Actually, the molecular weight of the unpolymerized fraction varies according to the nature o the starting rosin-containing material used and according to the method of @reparation of the oK terial may have been subjected. The given figure of 71/2 % represents a value arrived at by estimating the amount of, polymer required upon the 3( basis of experimental data. A serles of experiments were run in which various amounts of a commercial polymerized , rosin known as ."Nuroz," which inay coniain from 25 to 40% of polymer, were blended with natural "WW" wood 31-) rosin In various proportions. The restilting blends were used as starting materials in the preparation of resinates, the stability, refusibility and clarity of whi6h were then determined. ,There is apparently a de:ftnite relationship be40 tween the permanent refusibility of the novel resin-like products of our invention and the non-gelling of the petroleum solvent solution of these products, for gelling solutions are apparently formed only from those products which 43 are not permanently refusible, and, conversely, all the permanently refusible solid resin-like products of our Invention form stable solutions in petroieum solvents and the like without the addition of a stabilizing agent. 50 The novel resinates of our Invention have physical properties reseiiibling those of typical resins, being characterized, for instance, by a conchoidal fracture. The value of our products lies not so much in 55 their zinc content for Us drier effect or in their calcium content for its hardening effect toward coating materials, as in making available novel, high melting point synthetic resin-hke products for use as'substitutes for or in conjunction with co known synthetic resins, such as ester gum, alkyd and phenolic resins and their modifications. our permanently refusible resin-like products impart added properties of hardness, through drying, gloss, iinproved pigment dispersion and crther 65 valuable ebaracteristies to varnish, enamels, inks and simflar coatings. It is therefore an important object of our invention to provide novel, high melting point resin-like products of a permanently refusible 70 character and capable of forming stable nongeHIng solutions In petroleum solvents, the products being clear resinates of zinc and calcium high in zinc and calcium content and being substantiauy free of uncombined metal ancl hqving 5 the valuable properues of lmp&rung hilrdness. through drying, Improved pigment dispersion and other desir&bia- characterinucs to varnish, enamels, Inks and el-'la co&Unp. Another Important object of this invention is to provide a fusion method for the preparation of such resin-like products from heat treated rosin, catalyticauy polymerlmd rosin and the like. A further important object of this Invention Is, to provide a fusion method of -Wng a substantially neutral or bode zinc-Wcium r'esinate having perml&nently refusible characteristics and capgble of forming stable, non-gauing solutions in petroleum solvents and the like. Other and further iniportimt objects of this Invention will become apparent from the fouowing description and appended claim. Suitable starting - rltls for our process inelude partiallr polymerized pine oleoresin or partially polymerlmd rosins such -as heat treated rosins and catalytic#My polmerized rosim or pine oleoresin. Partial polymerization may, be effected by heat treating gum or wood rosin in accordance with a method described and claiined in Logan Patents Nos. 1,643,276 and 1,807,483. period between eight hours for the lowest temperatures and ten minutes for the higher temperatures. The amount of polymerization is greater the more prolonged the heat treatment. Where "heat treated" rosin is herein referreo to It WiU be understood to be rosin that has been subjected to heat treatment such as described In the aforesaid Logan patents, or an equivalent heat treatment. Partial polymerization may also be effected by means of a catalyst in accordance with the methlods of such patents as those to Schnorf, No, 2,074,192, Rummelsburg, Nos. 2,108,928, and 2,124,675, and to Morton, No. 2,017,866, or, preferably, In accordance with the method described and claimed In the Palmer and Bibb Patent No. 2,224,399, filed September 28, 1939, and granted JUly 1, 1941. Since the products so obtained are generally referred to as polymeri7,ed rosin, that term will be used herein to designate polymerized rosin produced by the action of a polymerization catalyst and containing a. substantlauy greater proportion of polymers of is resin acid than that present In a heat trbated rosin. In general, a polymerized rositi such as the cornmercial polymerized rosin known as "Nuroz" contains some 25 to 40% of dimer. Throughout this specification and In the claims, where percentages are referred to, percentages by weight are Intended unless otherwise %milled. A polymer content of about 71/2% or m'ore polymer Js preferably treated differently from a rosin containing less polymer. Obviously any desired polymer content of any rosin used as starting material can ).* obtained either by a heat treatment or a polymerizing treatment of the rosin to be used as starting material or by blending with the rosin to be used a3 starting material heat treated or polyzlierized rosin in amounts sufficient to effect the desired polymer content in the rosin to be used as a' starting material. 7'1@e,starting materials described hereinabove are reacted by fusion with hyclftted lime aW with zinc oxide, hy&o3dde or carbotiate, preferably at a temperature of frori 2000 to Soo* C. A eata. lyst is added to the reaction maw, acetic add being preferred. Other c4talysU enumerated in rosin-cont&Wng material as well as the nature of --, According to these patents, rosin is heated at any treatment to which the rosin-containing ma- a temperature between 2600 and $25" C. for a

the Romgne et *I Patent No. 1,884,40,7 may be employe d, however. especlally ca"ats sekweted from the group consisting of orgwo scidssoluble in rosin at the reaction temperature whose acidity is due to a carboxylic acid radical, orgemic adds 5 soluble in rosin at the reaction tempeiliture whose acidity is of a phenolic nature, and salts of mod acids capable of reacting with abletic acid to .Uberate said acids such as formic acid, lactic acid, tartarie'acid: -citric acid, or a MeW salt 10 (includin g a--onium salts) of these and other carboxyl ic acids, in particular, fatty acids of low molecula r weight. Since 4 catalyst must be present at aR stages of the fusion in order to ha@e the reaction go 15 to completion, It is essentidl to avoid the loss or destructi on of the catalyst during the fusion process, if substantially all of the zinc compound and the lime is to be combined with'the rosin, and If a clear resinate product Is to be produced. 20 Several methods are available for avoiding the loss or destruction of the catalyst. Thus, If the reaction temperature Is maintained, for exaniple, at about 2400 C. or above, the catalyst may be added with the lime or with the zinc compound. 2,3 T.f acetic acid is used, the acid wiU react with the ' lime or zinc compound to form the corresponding acetate which is not volatile at the reaction temperature but may decompose gradually. To prevent the formation of lumps of acetate and to aid 30 in the fusion reaction, the mixture of Ume and acetate or zinc oxide and acetate may, be wetted with barely enough liquid to form a slurry. An off, such as a petroleum solvent, may be used that will volatilize during the fusion process. V#Ihen 35 such an oil is employed with the metal compounds, the quantity of oil employed is In no case sufficient to effect a reaction in solution rather than a fusion reaction. Water may also be used to form a slurry. 40 The amount of catalyst required to give a clear res@In will obviously depend upon the manner in which'the fusion reaction is conducted and upon the particular means adapted to insure the presence of a catalyst during the entire reaction, 45 but from 1/2 part to about 1 part by weight for each 100 parts of rosin is usuauy sufficient. Whether or not a clear, permanently refusible fb2al product capable of forming a stable, nongemng solution Is obtained depends upon the 30 amount of zinc compound and lime reacted with the rosin, upon the sequence of additions of zinc compound and lime, and upon the nature of the rosin used as starting material. 7be order of addition as between the lime and 65 the zinc compound depends upon the polymer content of the starting material employed. It Is not usually possibie, when starting with a rosin containing a substantial amount of polymer ranging up to about 71/2%, to react as much as do 6% zinc oxide without getting. an infusible product in the fusion reaction, unless calcium resinate already is present. Calcium resinate provides the necessary stabilizing effect required for the preparation of a resinous product distinguished 65 by permanent refusibility and by capacity, for forriiing stable, non-gelling solutions. In the case of a rosin containing a substantial amount. of polymer not in excess of about 71/12%, we have found that when such rosin Is reacted first with 70 lime and then with a zinc compound, further reaction can be effected with an additional amount of lime. In the case of a rosin containing at least about 71/2 % polymer, the presence of a stabilizing ageiit 7a such u calcium resinstof is not reqwred to prevent the formation of an Infusible resinous product. Hence the zinc oxide may be Ant reacted with.the rosin and the lime added subseciuently. 7be acidity. or ba4icity of the :final product depends uporr the proportions of the zinc o3dde and hydmted lime employed. 1% of zinc oidde (ZnO) will theoreticauy drop the acid vsdue of the rosln 13.78 points, while 1% hydrated Ilme (Ca(OH)2) Will drop the acid i5.13 points. In the case of reacting proportions of zinc oxide and hydrated lime, the Oereentages specified in the specification and In the claims are based on the weight of the rosin acid containing material. -In the case, for example, of a heat treated rosin having an acid value,of 142, this rosin may be first reacted by fusion with 2.15% of hydrated Ume dropping the acid vaiue by about 42 points, and then with 6% of zinc oxide dropping the acid value by about 83 points, to yield a clear resin-like product containing zinc-calcium resinate. We find that if between 2.75 and 31/2% of hydrated lime has been reacted with the rosin before the zinc compound Is reacted with the rosin, about 6% of zinc oxide may then be reacted by fusion to form a clear refusible resinous product. However, the product will not be clear if more than aliout 9% of combined lime and zinc oxide have been reacted in this manner. About 6 % of zinc oxide seems to be the maximum amount that can be reacted with the limed rosin to give a clear product. After 3 % of lime and 6% of zinc oxide have been reactedoith the rosin, more hydrated lime ban be reacted with the rosin to give a clear resinate that may be neutral or basic. For instance, addition of 2% more lime yields a resin of calculated basicity equal to about 17 acid value. The amount of hydrated lime thiat can be added In this third fusion step Is in general limited only by the extent to which the increased viscosity effected by such addition may make the product Impossible to handle. . As pointed out hereinabove, when a catalytically polymerized rosin containing more than about 71/2 % polymer is used as starting material, the order of addition of the metal compounds preferably is-different. The zinc oxide can then safely be added flrst and reacted completeiy with the rosin before the hydrated lime is added. In this way we have reacted 6*lo of zinc oxide wifh a chemically polymerized rosi , n of acid value 160 and then reacted 4% of hydrated lime with the rosin to produce a clear acid resin. Similarly, we have added 4% of hydrated lime to a chemically polymerized rosin to which 15% of zinc oxide had already been added, to produce a resin of a calculated basicity equal to 107 acid value and having a melting point of 168' C. (capidary tube). In another example we first reacted a catalytically polymerized rosin such as the commercial product known as "Nuroz" having an acid value of 160 and melting point of about 770 C. (capillary tube) with 5.5% of zinc oxide and then reacted the product with 9.5 clo of hydrated lime. Flurther additions of lime could not be made at the reaction temperature of 3000 C. because the reaction mass would then turn 'too visccus. The resin obta"!Tied was substantially clear, although all of the last 1 % of hydrated lime (the lime having been added in 1% increments) prcbably'did not completely react due to the high viscosity of the melted rosin. The reaction product had a capillary tube melting point of 204' C.

4 In thd case of catalytically, polymerlzed rosin, about 5 to 15% of zinc oxide may be.rescted with the roslii in the fint fusion step. Then at least 1% lime is reacted withthe resin In the second fusion step. Tiie tipper limit for the amount of hydrated lime Is set b@ th@ appea=ce of a viscosity so h igh that the maelt cannot be handled, and ;Wul-vary according to the amount of zinc oxide reacted with the rosin in the first fiision step. On the basis of substikntiauy complete reaction, the reaction products of rosin and 5, 6, 12, 13, and 15% of zinc oxide would contain about 3.8, 4.6, 8.8, and 10.8%. respectively, of combined zinc; and the reaction products of rosin and 1%, 3%, 4%, 5.50/o, 9.5%,of hydrated lime would contain about 0.5%. 1.6%, 2.1%, 2.8%, and 4.9% of combined calcium, respectively. The fouowing wM serve as an example of carrying out the fusion process of the present Invention. 100 parts of heat treated rosin are melted in a fusion kettle and about Y2 to 1.0 part by weight of acetic acid added while the rosin is stiu at A relatively low temperatare, say 1301 C. Aboilt 3 -parts by weight of hydrated lime are added to the molten rosin mass with stirring and the tem.; perature fncreased with iigitation until reaction is complete. At this point the temperature may be about 1800 C. The desired amount of zinc oxide, say'6 parts by weight, Is then added with agitation while continuing to raise the temperature and the reaction, carried out until complete, as indicated by a clear melt. The final temperature may be as high as 3000 C' The resulting resinlike product Is permanently refusible and can be-dissolved in Petroleum distillates, such as mineral spihts, without gelling upon prolonged heating. It will, of course, be understood that various details of the process may _b,e varied through a wide range without departin@g from the principles of'this invention. and it Is, therefore, not the purpose to limit the patent, granted hereon otherwise than necessitated by the scope of the appended claims. In these claims, the term "rosin'lis used generically to include pine oleoresin. We