Modified natural resin binder and process for preparation
United States Patent 1191 Rudolphy [45] Apr. 29, 1975 [54] MODIFIED NATURAL RESIN BINDER AND 2,708,192 5/1955 Joesting 260/25 PROCESS FOR PREPARATION 2,802,797 8/1957 Lerch 260/25 2938,876 5/1960 Morris 260/25 1 inventor: Albert p 2.995.537 8/1961 Thompson 260/27 BB wlesbaden-Biebrlch, Germany 3,360,488 12/1967 Hall 260/23 3,654.203 4/1972 Daimer... 260/27 BB [731 Asslgnee- 3,674.732 7/1972 P11221115 260/25 ur am am, ermany [22] Filed: Oct. 3, 1972 Primary Examinerl-l. S. Cockeram Attorney, Agent, or F irm-Littlepage, Quaintance, [21] Appl. No.. 294,655 Murphy &amp; Dobyns F0l&#39;eign Application Priority Data O .8, 1971 19 I972 A process for the manufacture of a modified natural resin product wherein (a) a natural resin product such 52 US. Cl. 260/25; 106/218; 106/219; .&#39;P 9 acids 260/27 260/27 260/28 5 A et1c acid is reacted mm (b) at least one ethylemcally [51] Int. CL Cosg 5/22; Cosg 37/16; Cosd 9/12 unsaturated monomer havmg from 2 to 12 carbon [58] Field of Search 260/28 5 A 27 R 25 27 BB atoms and being free from carboxyllc groups and anhydride groups, and (c) a component selected from [56] References Cied the group consisting of a phenol resin per se and its components, a product obtained by said process and a UNITED STATES PATENTS binding agent containing said product. The products n are useful in adhesives and printing inks.  
 &#39; 4/1948 Rostlcr et al. 260/25 14 Claims, No Drawings MODIFIED NATURAL RESIN BINDER AND PROCESS FOR PREPARATION The invention relates to a process for the preparation of modified natural resin products.  
  The preparation of natural resin-modified phenol formaldehyde condensation products is known as is the possibility of modifying natural resin acids by reaction with unsaturated monoor dicarboxylic acids or their anhydrides or acrylonitrile r acrylates. These products can at least partially be esterified or reacted with suitable metal compounds to form resinates by salt formation. a  
  &#39;It is known to react additively natural resin acids under the influence of Friedel-Crafts catalysts or mineral acids in the presence of inert solvents with unsaturated compounds such as styrene or butadiene or the like. By the reactionof these: addition products with suitable metal compounds r&#39;esinsates are obtained which can be used for the preparation of drying oilcontaining paints.  
  These known reaction products have the disadvantage that they are unsuitable for many applications, e. g. for printing ink binders, because they are relatively little cross-linked and therefore too soft so that they are absorbed by the paper substrate and their dryingtime is relatively long. V  
  These disadvantages may be reduced or even a oided by the use of modified natural resin products prepared by the process according to the invention.  
  According to the present invention there is provided a process for the manufacture of a modified natural resin product wherein (a) a&#39;natural resin is reactedwith (b) at least one ethylenically unsaturated monomer free from carboxylic groups and anhydride groups, and (c) a phenol resin per se or its compnents. I  
  The resulting reaction product may if desired be at least partially esterified with polyhydric alcohols and may also if desired be reacted with minor quantities of carboxylic acids. If desired, the esterified or unesteri fied reaction products may be reacted with metal compounds to form metal saltsjThe products obtained according to the invention have the advantage that they have a certain desired hardeness and that despite this they have adequate solubility, particularly in aromatic solvents.  
  Preferred unsaturated monomers are those having 2 to 12, advantageously 4 to C-atoms, such as styrene, a-methylstyrene, vinyltoluene, indene, cyclopentadience, dicyclopentadiene and other olefins .or olefincontaining hydrocarbon fractions such as, for example, those obtained in petroleum distillation, in each case individually or in admixture. I i h i The natural resin can for example be in the form of natural resin acids such. as colophony wood rosin, tall rosin acids, abietic acid or the like. V  
  Suitable phenol resins include, for example, resols such as those prepared from phenol; alkylphenol such as isopropyl, p-tert, -butyl-, cotyl or nonylphenol; cresols, e.g., m-cresol; 1,3,5-xylenols; also those prepared fromdiphenylolpropane and cumylphenol. Resins of trifunctitonal phenols, i.e., those phenols wherein three 0- and/or p-positions&#39; to the phenol OH-group are free and reactive are preferred, The reaction of the natural resins with the phenol resin and the unsaturated monomers can take place in one or more stages but also in one stage in such a way that the phenol resin is either used as it is or is formed during the reaction from its ingredients. In the same way there are suitable the ingredients of these resins such as the above indicated phenols, as well as aldehydes with 1 to 7 C-atoms, particularly formaldehyde in various monomer and polymer forms, and also other aldehydes such as acetaldehyde, butyraldehyde, benzaldehyde, furfural or the like. By the use of phenol resin ingredients in the starting mixture the viscosity of the end products can be controlled in a convenient manner.  
  As polyhydric alcohols for the at least partial esterification can be used at least dihydric alcohols with 2 to 26 C-atoms such as ethane-, propane-, butane-, or hexanediols, glycerin, trimethylolethane or -propane, pentaerythritol, sorbitol, dialcohols or novolac or diphenylolpropane such as are, e.g. obtained by reaction with ethylene oxide as well as propoxylated phenolbutyraldehyde-novolacs. Esterification causes not only a reduction of the acid number but also an increase in the number of molecules and therefore a rise in the viscosity and melting point of the products. A lower acid number has a favourable action on compatibility with pigments and ahigher melting point on thermal stabillty.  
  Suitable reaction ingredients for salt formation to resinates advantageously include compounds of metals of the first and/or second group of the periodic system, such as magnesium, calcium and zinc compounds, particularly their salts or oxides such as magnesium oxide, magnesium acetate, calcium oxide, calcium acetate, zinc oxide, zinc acetate, zinc carbonate, aluminium acetate and sodium acetate. The metal salt groups react essentially neutral. In the same way as the esterification products the slightly acid or substantially neutral metal salts have good compatibility wiht pigments In addition, the metal salts, provided that their content is low, lead to the reaction mixture not becoming basic, permit a rapid reaction during esterification, and the formation of products with a higher melting point. As a result of the metal salts there is a speedier solvent escape printing ink binders.  
  The reaction with the unsaturated monomers normally takes place with addiion to the unsaturated double bondsof the natural resin acid, e.g., colophony. These addition products have as low a crystallisation tendency as pure colophony so that they can be worked reliably. Generally up to 1 mol. of the unsaturated monomer is added to the colophony double bond. It is not essential to use a catalyst, it merely being necessary to raise the temperature to about 200 to 280C, preferably 250 to 270C. When using a catalyst, e.g., peroxide such as di-tert.-butylperoxide, dilauroyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis-(tert.-butylperoxy)- hexane, 2,5-dimethyl-2,5-bis-(tert.-butylperoxy)-hexene, dibenzoyl peroxide, cumene hydroperoxide, and/or metal salts with an accelerating action such as cobalt salts, in particular cobalt carbonate, it is possible to work at lower temperatures e.g., to 200C, preferably to C.  
  The reaction between the natural resin, the unsaturated monomer and the phenol resin can be performed in random sequence. For example (a) the natural resin and/or (b)&#39; the phenol resin can be first reacted with the monomer and then the other ingredients (a) or (0) can be reacted. A further possibility is e.g., to react only the phenol ingredients or only the natural resin ingredients with the monomer and then react with the other ingreclients (a) or (c) and optionally with the remaining monomer. In the known reaction of phenols with unsaturated monomers it is also possible to use catalysts such as mineral acids, organic acids, preferably toluene sulphonic acid or phenol sulphonic acid or Friedel-Crafts catalysts. The thus obtained products are then condensed with formaldehyde in the presence of alkali or ammonia, whereby further unsaturated monomers as solvents are superfluous. The condensation with formaldehyde can also take place simultaneously with the reaction with the natural resin.  
  If, in addition, reaction with a carboxylic acid is involved, it is for example possible to react (a) the natural resin optionally together with (c) the phenol resin or its ingredients, firstly with the unsaturated carboxylic acid ingredients or the monomer, optionally then reacting the other ingredients (c). It is also possible to initirally react the phenol ingredients with the monomer and then ingredients (a). In all cases it is possible to optionally react further reagents such as polyhydric alcohols and/or metal compounds. A further possibility is that, e.g., firstly only the unsaturated carboxylic acids ingredients are reacted with the monomer, e.g., maleic acid with styrene in known manner with telomer formation. Preferably, however, the natural resin is firstly reacted with the unsaturated carboyxlic acid ingredient, advantageously dicarboxylic acid with adduct formation.  
 A further embodiment of the invention comprises that the natural resin or reaction product serving as the starting material is additionally modified with a modifying carboxylic acid with 3 to 9 C-atoms, e.g., a dienophilic monoor polycarboxylic acid or its anhydride, advantageously maleic anhydride and/or further synthetic resins. The caboxylic acid increases the functionality of the products produced according to the invention. This functionality is, however, kept within limits by the incorporation of monomers. As a result of the incorporation of polar groups, also those of the incorporated phenols, the pigment wetting, particularly in the case of printing inks is improved. Generally minor quantities of acid, e.g., up to percent by weight based on the natural resin, particularly colophony are used.  
 In many cases it is, however, appropriate to use a larger acid proportion, thus an unsaturated acid ingredient can also be reacted in a proportion of over 5, advantageously 10 to 30 percent by weight based on the natural resin. Suitable acids are, for example, benzoic acid, succinic acid, adipic acid, phthalicacids, such as ophthalic acid, iso-phthalic acid, trimellitic acid, maleic acid, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, phenolcarboxylic acid as well as its derivatives, such as their anhydrides, in as far as these exists, esters, amides or the like. These acids can be at least partially esterified in the end product by the aboveindicated alcohols. In this way natural resin esters are obtained, e.g., of polyhydric alcohols, which are still esterified with small amounts of acid. The esterification of the carboxylic acids can take place before or after the addition thereof, whereby the above-indicated a1- cohols can serve as esterification ingredients. For the modification generally dienophilic carboxylic acid, advantageously maleic anhydride is preferred.  
  The unsaturated carboxylic acid which is added to this natural resin in larger quantities increases, in the form of the tricarboxylic acid thereby formed, the functionality of the reaction ingredients, whereby a higher cross-linking of the resins produced therewith is obtained. However, this effect is compensated or kept in limits to such an extent by the incorporation of unsaturated monomers that the resins produced according to the invention retain the solubility in organic solvents necessary for their use. As a result of the increased proportion of carboxy groups or the anhydride ester or carboxy groups produced therefrom, particularly good pigment-wetting characteristics of the reaction products are obtained, together with an improved storage stability of the binders produced therefrom.  
  If saturated, i.e., free from polymerisable bonds monoand/or polycarboxylic acids are used, their proportion is only small e.g., at most 5 percent by weight based on the natural resin.  
  Thus, with the process according to the invention it is possible to obtain natural resin esters, e. g., of polyhydric alcohols which are esterified with various acids. Acids present in the reaction mixture and unreacted with the natural resin can, e.g., form unsaturated polyesters with the alcohols which can also cross-link with the unsaturated monomers. Of the unsaturated dicar- :boxylic acids, however, 5 to percent by weight should be added to the natural resin whereby the percentage is based on the natural resin.  
  The process can be performed particularly advantageously if the unsaturated monomers in the first stage serve at least partially as solvents. This is particularly the case if a fraction of unsaturated hydrcarbons isused as the unsaturated monomer ingredient. These monomer compounds can thereby serve both as entraining agents as well as for the chemical incorporation in the reaction products.  
  In place of or together with the modifying carboxylic acids it is also possible to use other resins for the modification of the products obtained according to the invention, e.g., hydrocarbon resins, as obtained by the polymerisation of petroleum fractions or the like, including cumarone-indene resins and ketone resins such as cyclohexanone resins, methylethylketone aldehyde resins and benzophenone aldehyde resins. These resins are not per se particularly suitable for printing ink binders but can be used as diluents for the products accord- 7 ing to the invention. The proportion of modifying resins can be up to 250 percent based on the natural resin; advantageously however it does not exceed 100 percent.  
  The proportion of natural resins in the reaction products can be in the range of 15 to 85, advantageously 20 to percent by weight based on the total reaction product. Surprisingly, products with a relatively lower natural resin content of, e.g., only 15 percent by weight colophony have equally good printing characteristics as the hitherto known products with a higher colophony content. The colophony proportion can therefore be kept relatively low which leads to particularly inexpensive products.  
  The proportion of monomers is generally 0.2 to 20, advantageously 10 to 16 percent by weight based on the total reaction product. The molar ratio of the unsaturated monomers to the phenols amounts to generally 0.01 l 1, advantageously at least 0.5 1 and the molar ratio of formaldehyde to phenol is generally up to 2 l, advantageously 0.9 to 1.5 1.  
  The proportion of condensed or uncondensed phenols is generally 1 to 50, advantageously 25 to 35 percent by weight based on the total reaction product. In resinates the proportion of phenol resin is generally 10 to 40, advantageously to 35 percent by weight based on the colophony. It can, however, prove advantageous to reduce the phenol or phenol resin proportion to such an extent that as a result of the increased proportion of unsaturated dicarboxylic acid the functionality of the starting ingredients is increased.  
  If the reaction products are obtained in the form of their metal resinates it is advantageous if the metal content is 1 to 7, advantageously 2 to 4.5 percent by weight based on the total reaction product. Often mixtures of metals are advantageous, e.g., the ratio of metal proportion in the form of magnesium salts and the metal proportion in the form of calcium or mixtures of calcium and zinc salts can vary betweenn 2 l and 1 2. This is particularly advantageous for printing inks because among other things the storage stability is improved. Thus printing inks which contain magnesium resinates with yellow pigment dyes provide stable mixtures which during storage have a lower viscosity rise and a lower greening tendency than with the hitherto known toluene gravura resins which dry equally quickly and have the same content of yellow pigments.  
  Depending on the intended use according to the invention products can be obtained which have a higher or lower viscosity. This can, for example, be controlled by theselection of the quantity of monomer used. With a higher proportion of unsaturated monomers, for example resins of lower viscosity are obtained. The unsaturated monomers contained in the reaction products, particularly as mono-functional components, can also act as-chainstoppers against too great cross-linking. A further advantage of the products according to the invention is that they are more stable to oxygen than the known addition products which can be attributed to the reduced content of colophony and double bonds. As a result the films produced from these products are more resistant to embrittlement.  
  The resins obtained according to the invention have an overall reduced susceptibility to undesirable crosslinking phenomena and therefore have a good storage stability. In addition they have a good adhesion to substrates. As they have good solubility in conventional so1vents,particularly aromatics, such as toluene, xylene in aromatic-containing solvent mixtures and the resins produced according to the invention very rapidly give off the solvents, they are very suitable for use as binders for printing inks, particularly for toluenerotogravure printing. A higher proportion of phenol resin ingredients leads to a more rapid giving off of the solvents when using the products as printing ink binders.  
  Binders produced from the resins obtained according to the invention are further characterised by a very good adhesion to very varied substrates so that they are suitable for example particularly for printing foils of varied types, e.g., those of polylofeins such as polyethylene and polypropylene, particulary by means of flexoprinting. These printing inks resist the tear off test with adhesive tapes. In addition the resins are suitable as binders for other purposes particulary in combination with further polymers such as natural and synthetic rubber types, fatty oils, alkyd resins and other film constituents, so that they can be used in paints, adhesives and sealants. Here again the rapid giving off of solvents, good pigment-wetting, storage stability and compatibility prove advantageous. Those products produced according to the invention wherein the free carboxy groups are converted to salt or ester groups are particularly readily compatible with other binders, e.g., with chlorinated rubber and pigments. In adhesives containing polychloroprene rubber the resins produced according to the invention can increase the so-called assembly time but still have very good stability values. In the following Examples, which are given by way of illustration only, percentages are by weight.  
 EXAMPLE 1 1,500 g of balsam colophony are melted and 350 g of styrene added thereto. Within minutes the mixture is heated to 270C and kept for 7 hours at 270 to 275C. The volatile components are then removed for ten minutes at a pressure of 25 mm Hg by distillation. In this way 1,743 g of solid resin are obtained with a melting point of 58C (capillary method), and acid number of 124 and a viscosity of 9.1 cP (50 percent in toluene according to Ubbelohde).  
  900 g of the addition product obtained are melted and then esterified with 615 g of propoxylated phenoliso-butyraldehydenovolac with an OH-number of 280 in the form of 67 percent butanol solution in the presence of 0.5 g of zinc oxide. The novolac solution is thus added on reaching a temperature of 200C within 30 minutes accompanied by distillation of butanol. The mixture is then heated to 270C and as an entraining agent about 30 g of xylene are used. After a total of 10 hours reaction of the novolac, the entraining agent is removed at a pressure of 25 mm Hg. 1,248 g of a resin with a melting point of 56C (capillary method), an acid number of 40, a viscosity of 12 cP (accoding to Ubbelohde), a solubility in white spirit of 1 4 which is freely soluble in ethyl acetate and toluene are obtained,  
  The addition of styrene to colophony can, instead of as described above, take place at to C in the presence of peroxide, e.g., 3.5 to 40 g of t-butylperoxide and 0.35 g of cobalt carbonate.  
 EXAMPLE 2a Mixture 2a/ 1 2a/ 2 Phenol-formaldehyde-resin 40 g 59.5 g Magnesium oxide 15 g 7.5 g Calcium oxide 7.5 g  
 Yield 538 g 551 g Melting point (capillary method) 139C 125C Acid Number 52 35 Viscosity (50% in toluene) 300 cP 245 CI The mixture is heated for 1 hour at 200C, whereby 30 g of xylene and the metal oxides indicated in the Table are used. With return of the xylene heating takes place for 4 hours at 250 to 260C and finally under reduced&#39;pressure of 50 mm Hg for 5 minutes at 280C.  
 The products obtained can be seen from the above Table.  
  In place of magnesium oxide it is also possible to use zinc or calcium oxide, whereby the metal content of the product can, e.g., be 6.8 percent.  
 Printing Testing The binders are dissolved in toluene as a 50 percent solution and processed with 20 percent by weight based on the solid content of Pigmentrot 57 (Calcium salt lacquer of ,B-hydroxyoxynaphoic acid) by means of a rapidly rotating glass ball mill to a particle size of less than 51.1.. The printing inks obtained are adjusted to a 17 sec. outflow time by adding toluene to a 4 mm DIN- beaker and in each case drawn up by a 36 1.1. wire coil onto machine-coated paper or a non-absorbing terephthalate foil. The drying rates in seconds are determined by pressing down the side of the hand.  
  The printing ink applications to paper are left overnight and the gloss is determined by means of a Lange glossmeter. For comparison, a commercial gravure resin in the form of a colophony calcium zinc salt (melting point/capillary method 155C, acid number 70, viscosity 50 percent in toluene 270 cP) cross-linked with a water-soluble resol is tested. The results are given in the following Table.  
 EXAMPLE Com-  para- 2a/ 1 2a/2 tivc samplc Solvent given off in sec.) Machinecoatcd paper) 42 46 38 Terephthalatc foil 50 48 48 Lange glossmetcr Machine-coated paper*) 65 75 60 Outflow times in see.  
 after 4 weeks storage 17.5 19 28 In the table the tests with the resins obtained according to the invention show a substantially identically rapid giving off of solvents as the comparative tests with the higher melting commercial product, but also a higher gloss and after storage a considerably reduced increase in viscosity.  
 EXAMPLE 2b The same binders as in Example 2a are processed instead of with 20 percent pigment red with 12.5 percent of previously dispersed Pigmentgelb (yellow benzidine dye) in the same way as in Example 2a and tested with the following results:  
  These tests show that the printing ink binders with magnesium resinates produced according to the invention have a particularly favourable storage behaviour which applies both for the pure magnesium salts and for the mixed salts. The pure or mixed salts produced with other metal compounds such as zinc or calcium are also less susceptible to viscosity rises than the binders of the comparative test.  
 EXAMPLE 3a 450 g of phenol are heated in the presence of 27.75 cc of 0.5 Nl-lCl with 400 g of styrene to a temperature of C and the mixture is brought within 8 minutes to C. The mixture is refluxed for 3 hours at 1151 17C, then cooled. 12.65 cc of 33% NaOH and 236 g of paraformaldehyde are added, followed by reacting for 2 hours at 80C and cooling to room temperature. 1,126 g of a product with the following characteristics are obtained: viscosity (50 percent toluene solution according to Ubbelohde 20C) 3,480 cP, formaldehyde 3.6 percent, residue (2 g of resin per hours C) 78.5 percent.  
  In place of styrene it is also possible to react the corresponding amount of methyl styrene or vinyl toluene and in place of phenol the corresponding quantity of butylor octyl-phenol or diphenylolpropane.  
  1,500 g of Portuguese colophony are melted and at C mixed with 100 g of glycerin and 20 g of zinc oxide. At 130C 950 g of modified phenol resin are added and the mixture is heated to 260C within 3 /2 hours, and is then kept at this temperature for 3 hours and finally the volatile ingredients are removed for 15 minutes at 50 mm Hg. 2,248 g of resin with the following characteristics are obtained: melting point (capillary) 124C, acid number 34, viscosity (50 percent in toluene according to Ubbelohde at 20C) 328 cP.  
 EXAMPLE 4a 725 g of phenol are melted,&#39;and then 350 g of indene at 50C, followed by 0.5 cc of a 65 percent solution of p-phenolsulphonic acid are added. After 3 hours reaction under reflux at 178 194C, cooling to 40C takes place. Then 7.5 cc of 33% NaOH and 244 g of paraformaldehyde are added and condensed for 2 hours at 80C. 1,325 g of resin with the following characteristics are obtained: viscosity 2,690 cP, formaldehyde content 0.6 percent, residue 75.5 percent.  
  1,232 g of this resin are reacted with colophony according to Example 3a. 2,457 g of a resin with the following characteristics are obtained: melting point (capillary) 1 19C, acid number 47, viscosity (50 percent in toluene) 484 CR EXAMPLE 5a Working as in Example 4a, but instead of indene, a mixture of 70 g of indene, 70g of styrene, 70 g of vinyl toluene and 70 g of dicyclopentadiene is used. Refluxing takes place for 3 hours at 182 194C, followed by condensing with the same quantities of NaOH and paraformaldehyde. 1,255 g of resin with the following characteristics are obtained: viscosity (according to Ubbelohde) 2,510 cP, formaldehyde content 0.6 percent, residue 73.2 percent.  
  The resin is processed further as in Example 4a and 2,385 g of a product with the following characteristics are obtained: melting point 1 19C, acid number 47, viscosity (50 percent in toluene) 431 cP.  
 EXAMPLES 3b to 5b Printing Tests The binders produced according to Examples 3a to 5a were tested from a printing standpoint according to Example 2a. The results are given in the following Table. For comparison purposes a resin based on one colophony reacted with diphenylolpropane-formaldehyde resin (Resol), maleic acid and pentaerythritol with a melting point of 135C, an acid number of 18 and a viscosity of 300 cP was used.  
  The Table shows that the printing inks produced with the resins according to the invention have excellent drying times and a better gloss than the&#39;comparative products. The excellent adhesion of the printing inksto polyethylene and polypropylene foils is particularly noteworthy. Thus, for example, it is not possible by means of adhesive tape to remove the ink layers from the foil substrates.  
 EXAMPLE 6 To 1,420 g of phenol were added at 60C initially 6 cc boron trifluoride-diethyl-etherate and then with 10 minutes 1,5 00 g of indene. The temperature was raised to 160C. The reaction mixture was then brought to 205 to 230C, refluxed at this temperature for 3 hours and then cooled. 2,925 g of a reaction product with a viscosity of 3,560 cP, which is compatible in any ratio with alcohol, acetone, ethyl acetate and ethylene glycol monoethyl ether, but is not compatible with benzene in the boiling range 160 200C.  
  1,500 g of colophony were melted at 170C with l 10 g of glycerin; 585 g of the reaction product obtained in the first stage, 400 g of a water-soluble phenolformaldehyde resol (molar ratio phenol formaldehyde 1 1.5; residue of 68.5 percent after 1 hour at 135C, viscosity 285 cP), 100 g of paraformaldehyde and g of zinc oxide are added. The mixture was kept for l hour at 100C, and then heated for 2 /2&#39;hours to 260C. kept for 3 /2 hours at this temperature, and then the volatile ingredients were distilled off under reduced pressure. 2,368 g of a reaction product with a melting point. of 127C, an acid number of 44 and a viscosity of 455 cP percent in toluene) were obtained.  
 . EXAMPLE 7 1,420 g of phenol were mixed at C with 6 cc of boron fluoride-diethyl-etherate. Within .15 minutes.  
 B-methyl-styrene, 62.3 percent by weight of indene and 20 percent by weight of non-olefinic ingredients. The temperature rises to 122C and drops after a few minutes to 118C. The mixture is then refluxed for 1 hour at 180 to 193C and then cooled. 2,226 g of a product with a viscosity of 172 cP, which is freely compatible with alcohol, acetone, ethylene glycol monoethylether and benzene of boiling range 160-200C is obtained.  
  .620 g of the reaction product and g of paraformaldehyde are reacted as in Example 6 with colophony. 2,186 g of resin with the following characteristics are obtained: melting point 125C, acid number 42, viscosity (50 percent in toluene) 515 CF.  
  The resins obtained according to Example 6 and 7 as printing ink binders also rapidly give off solvents and have a higher gloss than comparative products with known resins.  
 EXAMPLE 8 According to Example 1 1,820 g of balsam colophony are melted at C, 125 g of glycerin, 25 g of zinc oxide and 725 g of the phenol-formaldehydecondensate used in Example 2a are added. Prior to the addition of the resin 500 g of styrene are added. The mixture is heated for 5 hours with the removal of the water formed until 260C is reached and is kept at this temperature for a further 1% hours. 2,741 g of resin with the following characteristics are obtained: melting point 132C, acid number 47, viscosity (50 percent in toluene) 347 0?, freely solubile in toluene, colophony content 66.4 percent. 66.4 percent.  
  When working in the same way but without styrene the product gels at a temperature of 220C, so that it cannot be processed further.  
 EXAMPLE 9 450 g of tall oil resin are condensed under reflux for 2 hours with 470 g of phenol, 75 g of a 30 percent formaldehyde solution, g of para-formaldehyde and 10 g of zinc oxide. Then 60 g of maleic anhydride are added and after a further hour 100 g of styrene and the remaining 700 g of tall oil resin are added. On removal of the water formed, the mixture is heated to 170C and 158 g of glycerin are added. Heating then takes place at 250C, and at this temperature within 1 /2 hours a further 100 g of styrene are added. The temperature drops to 235C and then rises within 1 hour to 260C and is kept at this temperature for 4 hours. The volatile constituents are then distilled off under reduced pressure. After a totalof 11 hours 1,916 g of resin are obtained with the following characteristics: melting point 123C, acid number 37, viscosity (50 percent toluene solution) 610 cP.  
  The maleic anhydride can also partially be replaced by a dicarboxylic acid without olefinic double bonds, such as isophthalic acid.  
 EXAMPLE 10 1,500 g of colophony are melted and accompanied by stirring are added at&#39; 160C 100 g of glycerin, 20 g of zinc oxide, 350 g of indene and 650 g of a watersoluble phenol-formaldehyde resin (resol, viscosity 280 cP, residue 68.5 percent, molar ratio formaldehyde phenol 1.5 1). The mixture is heated for 3 hours at 260C. After a further 3 hours at this temperature the volatile ingredients are removed. 2,136 g of resin with the following characteristics are obtained: melting point 134C, acid number 44, viscosity (50 percent in toluene) 178 cP.  
  The product obtained is suitable both as a binder for gravure printing inks and as an ingredient in adhesives, particularly together with polychloroprene rubber.  
 EXAMPLE 1 1 1,500 g of colophony are melted at 160C, 14 g of calcium oxide are added and after 30 minutes 100 g of glycerin, 350 g of styrene and 600 g of the phenolformaldehyde resin according to Example 10. With the removal of water, heating takes place for 2 hours at 260C. Subsequently the volatile ingredients are removed under reduced pressure. 2,189 g of resin with the following characteristics are obtained: melting point 122C, acid number 44, viscosity (50 percent in toluene) 434 cP. The product obtained is suitable as a printing ink binder and for adhesives.  
 EXAMPLE 12 A mixture of 1,500 g of molten colophony, 100 g of glycerin, 20 g of zinc oxide, 350 g of styrene, 675 g of phenol-formaldehyde resin (molar ratio formaldehyde phenol 1.5 1 resol), 64 g of p-cumyl-phenol and 15 g of formaldehyde are heated for 4 hours at 260C and reacted at this temperature for a further 3 hours. 2,316 g of a resin with the following characteristics are obtained: melting point 122C, acid number 41, viscosity (50 percent in toluene) 353 cP. The product obtained is suitable as a binder for printing inks and adhesives.  
 EXAMPLE 13 500 g of colophony are melted with 1,000 g of dimerised colophony, 91 g of glycerin, g of zinc oxide, 350  
 g of styrene 450 g of phenol-formaldehydecondensation product are added and the mixture is heated for 3 hours at 260C. After a further 3 hours at 260C the volatile ingredients are distilled off under reduced pressure. 2,097 g of resin are obtained with the following characteristics: melting point 125C, acid number 47,.viscosity percent in toluene) 155 CP. The product obtained is suitable as a binder for printing inks and adhesives.  
 EXAMPLE 14 Working as in Example 13, but instead of dimerised colophony here 1,000 g of a partially intramolecularly esterified reaction product of colophony and phenol (molar ratio about 1 1 are used. 2,143 g of resin with the following characteristics are obtained: melting point 124C, acid number 41, viscosity (50 percent in toluene) 107 cP.  
 EXAMPLE 15 1,500 g of colophony are melted and 300 g of a telomer of 8 mol of styrene and 1 mol of maleic anhydride (melting point 100C, acid number 62, viscosity 64 cP) are added at 170C. At 150C 1 1 1 g of glycerin, 20 g of zinc oxide, 350 g of styrene and 625 g of phenol-formaldehyde resin according to Example 10 are added. The mixture is heated for 3 hours at 260C and after a further 2 hours the volatile ingredients are removed. 2,518 g of resin with the following characteristies are obtained: melting point 125C, acid number 39, viscosity (50 percent in toluene) 371 cP.  
 EXAMPLE 16 1,500 g of colophony are melted and at 160C 20 g of maleic anhydride, and then 15 g of sorbitol, g of glycerin and 250 g of a propoxylated butyraldehydephenol-novolac (hydroxyl number 270) are added as further esterification components. Then 350 g of styv rene, 20 g of zinc oxide, 500 g of phenol-formaldehyde resin according to Example 10, 150 g of phenol and 55 g of paraformaldehyde are added. Condensing takes place for 1 hour at C and then with continuous water-removal heating takes place for 2 hours at 260C. Then over the period of one hour the volatile ingredients are removed at 250C under reduced pressure. 2,510 g of a resin with the following characteristics are obtained: melting point 122C, acid number 40, viscosity (50 percent in toluene) 370 CP.  
  The products of Examples 14 and 16 are suitable both as binders for printing inks and adhesives.  
 EXAMPLE 17 1,200 g of colophony are reacted with 600 g of a hydrocarbon resin (melting point 142C, acid number 28, viscosity cP) modified with maleic anhydride, 20 g of maleic anhydride, 15 g of pentaerythritol, 350 g of styrene, 400 g of phenol-formaldehyde resin (resol according to Example 10), 380 g of phenol and g of paraformaldehyde, in the presence of 20 g of zinc oxide. With water removal the mixture is brought to 260C and by adding xylene under continuous return flow is kept for 3 hours at 260C. The volatile ingredients are removed for a further 15 minutes at 50 mm Hg. 2,730 g of resin with the following characteristics are obtained: melting point 124C, acid number 38, viscosity (50 percent in toluene) 290 cP, colophony content 44 percent by weight. The resin is suitable both as a printing ink binder and for adhesives.  
 EXAMPLE l8 Processing takes place as in Example 17, but with 600 g of cumarone indene resin (melting point 80C, acid number 0.1, viscosity (50 percent in toluene) 13 cP) in place of hydrocarbon resin and with vinyl toluene in place of the same amount of styrene. 2,740 g of resin with the following characteristics are obtained: melting point 116C, acid number 38.7, viscosity (50 percent in toluene) cP, colophony content 43.8 percent by weight. The resin is suitable for printing ink binders and for adhesives. In place of the cumarone resin it is also possible to use ketone resin, e.g., based on methyl-cyclohexanone-hexanone-formaldehyde resin (melting point 120C).  
 EXAMPLE 19 Processing takes place as in Example 17, but will 900 g of colophony and 900 g of a hydrocarbon resin (melting point 95C, acid number 0, viscosity (50 percent toluene solution) 20 cP). In place of the styrene a mix- If in place of the 900g of hydrocarbon resin, 1,050 g thereof is used, and in place of the 900 g of colophony only 450 g thereof, and in place of the monomer mixture 350 g of styrene are introduced, 2,467 g of resin with the following characteristics are obtained: melting point 104C, acid number 25, viscosity (50 percent in toluene) 147 &#39;cP, colophony content 18.3 percent by weight.  
 The initially described product is processed to form 1 an adhesive having the following composition:  
  45 g of the resin produced according to the invention 100 g of polychloroprenc rubber 5 g of magnesium oxide 4 g of zinc oxide 370 g of solvent (ethyl acetate tolucnc benzenc=l:l:l)  
  Testing the adhesive mass led to an assembly time of below 8 hours, a separating strength rubber/rubber of 6.3 (at 20C) or 0.9 (at 50 C) kg/cm and a thermal stability of 12 minutes at 50C.  
 EXAMPLE 20 1,000 g of colophony are melted with 650 g of pphenylphenol and l 15 g of octylphenol and after adding a mixture of 100 g of styrene, 50 g of vinyl toluene, 50 g of indene and 100 g of dicyclopentadiene condensed with 300 g of paraformaldehyde and g of zinc oxide for 2 hours at 100 120C and then with continual water removal heated to 260C. This temperature was maintained for 3 hours and as reactive monomers &#39;wh&#39;ich simultaneously serve as entrainers are added 100 g of a hydrocarbon fraction from petroleum distillation which contains 38 percent by weight of styrene, 27 percent by weight of xylene, 15 percent by weight of ethylbenzene, 18 percent by weightof cumene and 12 percent by weight of 1-methyl-4- ethylbenzene. 2,095 g of resin are obtained with the following characteristics: melting point 11 1C, acid number 67, viscosity (50 percent in toluene) 34.2 CF. The resin is suitable for printing ink binders and adhesives.  
  Testing of the adhesive mass took place as in Example 19 and led to an assembly time of 60 minutes, a separating strength rubber/rubber of 5.0 at 20C and 1.7 at 50C kg/cm and a thermal stability of 30 minutes at 50C. The resins produced according to the invention have a longer assembly time and a considerably higher thermal stability than the comparative test with a known resin.  
 EXAMPLE 21 1,500 g of Portuguese colophony are melted and 900 g of styrene and 900 g of phenol-formaldehyde resin (resol according to Example 10) are introduced With continuous removal of water, the mixture is heated for 3 hours&#39;at 270C and by adding 30 to 60 cc of xylene with continuous reflux kept at 270C fO1&#39; 3 hours. The volatile ingredients are then removed under reduced pressure. 2,896 g of resin with the following characteristics are obtained: melting point 108C, acid number 62.3, viscosity (50 percnet in toluene) 121 cP, colophony content 51.7 percent by weight. The resin is suitable as a binder for printing inks and adhesives.  
 EXAMPLE 22 333 g of colophony are heated to 160C with 300 g of a propoxylated phenyl-isobutyraldehyde-novolac (melting point by the capillary method 50C, OH- number 260) produced from 1 mol of phenol, 0.7 mol of isobutyraldehyde and 1 mol of propylene oxide and mixed with g of maleic anhydride. After 30 minutes at 180C 9 g of zinc oxide, 250 g of styrene and 113 g of a water-soluble phenol-formaldehyde resin (resol, molar ratio formaldehyde: phenol 1.6 1, hardening residue 68.5 percent after 1 hour at 135C) and 32 g of glycerin are added. The mixture is heated to 270C with water removal and with the addition of -a total of 30 ml of xylene with continuous return of the solvent kept at 270C for 3 hours. The volatile ingredients consisting of the entraining agent, unreacted phenol and monomer proportions are removed by evacuation for 15 minutes at 50 mm Hg and 270C. 1,000 g of resin (colophony content 35 percent) with the following characteristics are obtained: melting point by the capillary method 1 17C, acid number 25, viscosity 1,200 0F (50 percent in toluene according to Ubbelohde at 20C), freely soluble in toluene-The resin is, e.g., suitable as a printing ink binder and as an additive resin to polychloroprene adhesives.  
 EXAMPLE 23 Processing takes place as in Example 22, but without glycerin. 995 g of a less viscous resin than in Example 1 are obtained with a colophony content of 33.5 percent, and the following characteristics: melting point 1 10C, acid number 46, viscosity 241 cP, freely soluble in toluene. The resin can be used for the same purposes as that the Example 22.  
 EXAMPLE 24 1,500 g of American wood colophony are heated with -3 15 g of maleic anhydride for 30 minutes at 220C, and then 15 g of zinc oxide are added. After a further 15 minutes at 220C 320 g of glycerin and 250 g of a phenol-formaldehyde resin (visocity 9800 cP, formaldehyde content 0.75 percent, hardening residue 80.5 percent after 1 hours at 135C), modified with 34.7 percent by weight of styrene and 500 g of styrene are added. The mixture is heated at 240C with continuous return of the styrene.,Within 70 minutes a further 100 g of styrene are added dropwise whereby the mixing temperature in 30 minutes is raised to 200C. By gradual addition of g of a petroleum fraction with a high olefin content (29 percent by weight of indene, 32 percent by weight of methyl-idene, 1.4 percent by weight of vinyl toluene, 8.2 percent by weight of ,B-methyl-styrene and the remainder non-olefinic ingredients) the temperature is adjusted to 260C with return of the unreacted monomers. After heating for a total of 3 /2 hours at 260C, the volatile ingredients are removed at 50 mm Hg within 15 minutes. 2,784 g of resin (colophony content 53 percent by weight) are obtained with the following characteristics: melting point 1 15C, acid number 49, viscosity cP. A mixture of 10 g of a 50 percent solution of this resin in toluene with 10 g of a 20 percent chlorinated rubber solution reveals no de-mixing characteritics after 14 days storage. This mixture is usable as a printing ink binder. It shows the good compatibility of the products according to the invention with chlorinated rubber.  
 EXAMPLE 25 1,500 g of colophony are heated to 200C for 30 minutes with 200 g of maleic anhydride. Then are added 20 g of zinc oxide and 250 g of glycerin, and subsequently 820 g of a resol (produced from the addition product of 1,776 g of phenol, 1.3 ml of 65 percent pphenolsulphonic acid and 1,840 g of styrene by subsequent alkaline condensation with 592 g of formaldehyde, viscosity 9,000 cP, formaldehyde content 0.45 percent, hardening residue 50 percent in 80 percent butanol after 1 hours at 135C). Then 100 g of a phenol-styrene-adduct (from 1,776 g of phenol and 1,840 g of styrene) and 60 g of formaldehyde are added and the mixture is heated for 1 hour at 120C, then for 2 hours at 260C and maintained at this temperature for 3% hours. Subsequently the volatile ingredients are removed after 15 minutes at 50 Torr and 260C. 2,644 g of resin (colophony content 56.8 percent by weight) are obtained with the following characteristics: melting point 130C, acid number 46.9, viscosity 467 cP, solubility in toluene random. The resin is equally compatible with chlorinated rubber as the product of Example 3 and is very suitable as a printing ink binder.  
 PRINTING TEST The printing test was performed as in Example 2a, the same comparison product being used as in Examples 3b to 5b.  
  In addition to dye residue was determined. A metal sheet was coated with 2 g of dye and 2 g of toluene and the mass was treated for A hour at 150C in the drying cubicle and then the residue was determined.  
  From the Table it can be seen that the printing inks produced with the resins of the invention not only dry equally quickly or considerably more quickly than the comparative product, but also have a better gloss. They adhere excellently to polyethylene and polypropylene foils.  
 EXAMPLE 26 150 g of colophony and 600 g of maleic-anhydridestyrene telomer (molar ratio 1: 8, molecular weight 1,800) and 100 g of cumarone indene resin (melting point 80C, acid number 0.1, viscosity 13 c?) are heated with 45 g of maleic anhydride for 1 hour at 200C, and then g of pentaerythritol, g of glycerin and 20 g of a 70 percent isobutanol solution of a propoxylated phenol-isobutyraldehyde-novolac (OH- number 260, calculated as solid resin) are added. To remove the isobutanol heating takes place at 200C at 50 mm Hg. Then 100 g of styrene are added and the mixture is heated to 260C, accompanied by water removal on the reflux condenser, and with the addition of a total of 30 ml of xylene this temperature is maintained for 3 hours. Then the volatile ingredients are removed under reduced pressure. 1,133 g of resin (colophony content 13.2 percent by weight) are obtained with the following characteristics: melting point 101C, acid number 40, viscosity 239 cP.  
 EXAMPLE 27 2,250 g of colophony and 525 g of styrene are heated at 270C for 3% hours with the return of the styrene and with the removal of 2 ml of water. From the obtained reaction product 617 g are heated with 52.5 g of maleic anhydride for 30 minutes at 200C, and then 30 g of an alkaline condensed p-tert.-butylphenolformaldehyde resin are added (molar ratio 1:1.6 melting point 60C. After a further 30 minutes 50 g of zinc oxide are added within 15 minutes and the mixture is heated to 260C. Then 30 g of glycerin are added dropwise and the mixture is kept at this temperature for 2 hours with a return of xylene and the addition of a total of 30 ml of xylene. The volatile ingredients are then removed. A total of 24 ml of water are separated. 715 g of resin (colophony content percent) are obtained with a melting point of 126C, acid number 90, viscosity 46.4 cP.  
 EXAMPLE 28 To 1,500 g of molten colophony are added at 160C, g of maleic anhydride and then 15 g of sorbitol, 75 g of glycerin and as further esterification components 250 g of a propoxylated isobutyraldehyde-phenolnovolac (hydroxy number 270). Then 350 g of styrene, 20 g of zinc oxide, 500 g of a water-soluble phenolformaldehyde resin (resol, viscosity 280 cP, residue 68.5 percent, molar ratio formaldehyde phenol l.5 l), g of phenol and 35 g of paraformaldehyde are added. Condensation takes place for 1 hour at 100C, then with continuous water removal heating takes place for 2 hours at 260C. Then over the period of 1 hour the volatile ingredients are removed under reduced pressure at 250C. 2,510 g of a resin (colophony content 59.7 percent) with the following characteristics are obtained: melting point 124C, acid number 46, viscosity (50 percent in toluene) 370 cP.  
  The product is suitable both as a binder for printing inks, particularly for toluene gravure, as well as for adhesives.  
 EXAMPLE 29 1,200 g of colophony are reacted with 600 g of a commercial hydrocarbon resin (melting point 142C, acid number 28, viscosity cP), modified with 5 percent of maleic anhydride, 20 g of maleic anhydride, 15 g of pentaerythritol, 350 g of styrene, 400 g of phenolformaldehyde resin (resol according to Example 22), 380 g of phenol and g of paraformaldehyde in the presence of 20 g of zinc oxide. With water separation, the mixture is brought to 260C and by adding xylene with continuous return of the xylene kept for 3 hours at 260C. The volatile ingredients are removed after 15 minutes at 50 mm Hg. 2,730 g of resin are obtained with a melting point of 124C, acid number 38, viscosity (50 percent in toluene) 290 cP, colophony content 44 percent by weight. The resin is suitable both as a printing ink binder and for adhesives.  
 EXAMPLE 30 hydride for 30 minutes at 200C. Then 350 g of glycerin and 300 g of styrene are successively added and the mixture is heated for 3 hours at 240C with return of the styrene and water separation. Then at this temtoluene gravure printing&#39;on paper and polyethylene or polypropylene foils.  
 Comparative Test 7 If a resin is produced according to Example 32 but perature a further 300 g of styrene are added dropwise 0 over a period of 21/2 hours and the mixture isheated at without any styrene, then the resin cross-links at 220 C 260C and with the addition of xylene kept at thistemand becomes unusable perature for a further hour. The volatile ingredients are Printing Test finally removed and 2,873 g of resin (colophony con- The printing test of the resins according to Examples tent approximately 60 percent) are obtained of melting 1O 26 to &#39;32 was performed in accordance with Example point 135C, acid number 50, viscosity 135 CR 25. The results are given in the following Table 2.  
 Table 2 Examples Comparative 26 27 28 29 30 31 32 product Dye residue 35.6 46.4 40 41 46.2 42.1 38.2 40.1  
 as a percentage Solvent given off in seconds:  
 Machine-coated 58 55 52 46 50 42 45 62 paper.  
 Terephthalate 65 58 56 50 55 53 49 78 foil Lange gloss value:  
 Machine-coated paper. 73 v 95 g 85 87 84 86 79 68 EXAMPLE 3 1- 1,500 g of colophony and 120 g of maleic anhydride are heated for &#39;1 hourat 200C; Then 40 g of zinc oxide are added; After minutes g of glycerin and 230 g of pentaerythritol are added. At 160C350 g of a phenol-formaldehyde resin (prepared by adding 1,270 g of styrene to 1,776gb&#39;f phenol) under the action of p-toluene-sulphonic acid, and&#39;then alkaline condensation with 592 g of formaldehyde; characteristics: viscosity 3,020 0?, free formaldehyde 0.45 percent, stoving residue 2 g of resin for 1 hour at 135C, 78 percent) modified with styrene. The mixture is heated for 2 hours&#34; at 250C and kept for 3&#39; hours at this&#39;temperature under normalpressureand then for 1 hour at 50 mm Hg and then emptied. Yield: 2,072 g of resin (colophony&#39;content 72.3 percent) are obtained, melting point 136C, acid&#39;number 39, viscosity 500 cP, solubil ity in toluene random. 10 g of a 50 percent toluene solution of the resin are mixable without separation with 10 g of a 20% chlorinated rubber solution. The resin is excellently suitable as an gravure dye binder.  
 EXAMPLE 32 To 450 g of tall oil resin acid are added 470 g of phenol 150C and the mixture is mixed with 75 g of percent formalin solution, 150 g of paraformaldehyde and 10 g of zinc oxide. The mixture is condensed under reflux for 2 hours and then are added 60 g of maleic anhydride, followed by condensation under reflux for 1 hour. After the addition of 700 g of tall oil resin acid and 100 g of styrene the mixture is heated accompanied by water removal to 170C. 158 g of glycerin are added and then within 1 /2 hours at 250C are added dropwise 100 g of styrene at reflux. The temperature thereby drops to 235C and within 1 hour reaches 260C. With the addition of xylene and accompanied by water removal the mixture is kept for 4 hours at 260C. Then the readily volatile ingredients are removed and 1,916 g of resin (natural resin content approximately 60 percent) are obtained. Characteristics: melting point 123C, acid number 37, viscosity 610 cP, solubility in toluene random. The resin is suitable for It can be seen from the Table that the printing inks with the resins produced according to the invention not only have a more rapid giving off of the solvent, but also much higher gloss values than the inks from the comparative resin.  
 EXAMPLE 33 1,500 g of colophony are melted together with 20 g ofmaleic anhydride. At 200C 750&#39; g of p-tert.- butylphenol and 230g of glycerin are added. The temperature drops to C and 330 g of paraformaldehyde and 10g of.-33 percent caustic soda solution are added, followed by condensation for 3 hours at 120 to C at reflux. Then 300 g of styrene and a further g of maleic&#39; anhydride are added, followed by heating for&#39;2 hours at 260Cwith water removal. By adding 60- &#39;ml of xylene the temperature is kept constant at 260C: Then the unreacted butylphenol and xylene are removed under reduced pressure and 2,637 g of resin (colophony content 56.8 percent) are obtained of melting point 127C, acid number 26, viscosity 126 cP.  
 Production of a lacquer:  
  50 parts of linseed oil and 25 parts of the resin obtained are heated to 250 C. After cooling 0.05 percent by weight of cobalt, 0.36 percent by weight of lead and 0.01 percent by weight of manganese naphthenate are added. Then the mixture is adjusted by adding white spirit to 80 seconds outflow time in a DIN/4 mm beaker.  
 Comparative Test A resin (melting point 132C, acid number 20, viscosity 120 cP) produced from colophony, diphenylolpropane, formaldehyde and glycerin are in the same way processed to a lacquer.  
  Both samples are applied to glass plates with a wet coating thickness of 100 u, and dried for 24 hours at room temperature. The lacquer produced from the resin according to Example 33 has a smooth surface, whereas the comparative product exhibits wrinkling. It is not intended that the examples given herein should be construed to limit the invention thereto, but rather they are submitted to illustrate some of the specific embodiments of the invention. Resort may be had to various modifications and variations of the present invention without departing from the spirit of the discovery or the scope of the appended claims.  
 What we claim is:  
  1. A process for the manufacture of an ink binder being a modified natural resin product comprising reacting (a) colophony, wood rosin, tall oil, rosin acids or abietic acid with (b) at least one ethylenically unsaturated monomer having from 2 to 12 carbon atoms and being free from carboxylic groups and anhydride groups, and (c) either a phenol resin which is a condensation product of a phenol with an aldehyde having 1 to 7 carbon atoms or the components of said condensation product at a temperature in the range of l20to 280C.  
  2. A process as claimed in claim 1 wherein component (a) prior to its reaction with (b) and (c) or the reaction product obtained from the reaction of (a), (b), and (c) is reacted with a minor amount of a carboxylic acid having 3 to 9 carbon atoms, its anhydride or its esterification product with a polyhydric alcohol having 2 to 26 carbon atoms in which at least one carboxylic group is esterified.  
  3. A process as claimed in claim I wherein the reaction product obtained from the reaction of (a), (b) and (c) is esterified in an amount of at least 10 percent by weight of the free COOH-groups in the product with at least one substance selected from (d) a polyhydric alcohol having 2 to 26 carbon atoms, and (e) a mixture of (d) and a carboxylic acid having 3 to 9 carbon atoms.  
  4. A process as claimed in claim 1 wherein, said component (a) and the unsaturated monomer are reacted in the presence of a catalyst selected from the group consisting of (f) an organic peroxide, (g) a cobalt metal salt accelerator and (h) a mixture of (f) and (g).  
 compound is a compound of zinc, magnesium of calcium or a mixture thereof and wherein the metal content of the total reaction product containing metal salt groups is from 1 to 7 percent by weight.  
  8. A process as claimed in claim 7 wherein the amount of the magnesium in the form of its salt to the amount of the calcium or of the mixture of calcium and zinc in the form of their salts is within the range of from 2 l to 1 2.  
  9. A modified natural resin product obtained by the process of claim 1.  
  10. A binding agent containing a product as claimed in claim 9.  
  11. An adhesive which contains the binding agent of claim 10.  
  12. A printing ink which contains the binding agent of claim 10.  
  13. A process for the manufacture of a modified natural resin product wherein (a) colophony, wood rosin, tall oil or rosin acids are reacted with (b) at least one ethylenically unsaturated monomer having from 2 to 12 carbon atoms and being free from carboxylic groups and anhydride groups. and (0) either a phenol resin which is a condensation product of a phenol with an aldehyde having 1 to 7 carbon atoms or the components of said condensation product, wherein the monomer (b) is first reacted with phenol as component (c) in a molar proportion of components (b) (c) of (0.0l to l) l and subsequently the reaction product is further reacted with and formaldehyde and component (a).  
  14. A process for the manufacture of a modified natural resin product wherein (a) colophony, wood rosin, tall oil or rosin acids are reacted with (b) at least one ethylenically unsaturated monomer having from 2 to 12 carbon atoms and being free from carboxylic groups and anhydride groups, and (c) either a phenol resin which is a condensation product of a phenol with an aldehyde having 1 to 7 carbon atoms or the components of said condensation product, wherein the amount of the component (a) in the reaction product is from 15 to percent by weight, that of the monomer (b) is from 0.2 to 20 percent by weight of the reaction product and that of the phenol is from 1 to 50 percent by weight, referred to the total reaction product and wherein the phenol resin is based on a trifunctional phenol.