Abstract: A copolycondensation of a phenol, a naphthol and formaldehyde proceeds smoothly in the presence of an acid and a metallic element selected from the group consisting of transition metallic elements and metallic elements of Group IIa, Group IIIa, Group IVa, Group Va and Group VIa of the Periodic Table, and a naphthol-modified phenolic resin which has a large molecular weight and does not gel is obtained.

Abstract: Linear aromatic polymeric species, particularly oligomers and polymers are produced under mild conditions in good yield by reacting an at least binuclear aromatic compound with an alkylidene bisphenol in the presence of a non C-alkylatable hydroxy substituted aromatic compound effective to stabilize a generated carbonium ion intermediate; the alkylidene bisphenol may be formed in situ from a ketone or aldehyde in the presence of a catalytic amount of a hydroxy substituted aromatic compound effective to generate a carbonium ion with the ketone or aldehyde; carrying out the reaction under reduced pressure, particularly high vacuum permits direct production of high polymers; the oligomers are useful in the manufacture of high molecular weight engineering or industrial plastics; the polymers may be used directly as such plastics.

Abstract: A resin is prepared by the reaction of a phenol, an aldehyde and an aliphatic hydroxy compound containing two or more hydroxy groups per molecule in the presence of a divalent metal ion catalyst. These resins react with polyisocyanates to form polyurethanes that are useful binders for foundry cores and molds.

Abstract: One hundred percent thermosetting phenol/formaldehyde (P/F) resin and method of preparation thereof are disclosed. The resin comprises a molar ratio of F/P of about 1.2-1.7, has a softening point of about 80.degree. C. and cures at temperature of about 140.degree.-160.degree. C. The method comprises heating the reactants in a solvent-less system in the presence of an ortho directing catalyst while monitoring the amount of free formaldehyde present in the reaction system.

Abstract: Products of the condensation of phenolmonosulfonic acids, dihydroxydiphenyl sulfones, urea and formaldehyde can be obtained by(A) preparing a homogeneous reaction mixture in sulfuric acid from the phenolmonosulfonic acid and dihydroxydiphenyl sulfone in the molar ratio of from 3:1 to 10:1, with the proviso that the water content of the mixture is not more than 10% of the total weight of the components, and the mixture contains from 0.3 to 1.5 moles of sulfuric acid per mole of dihydroxydiphenyl sulfone, at from 100.degree. to 180.degree. C.,(B) subsequently, at from 40.degree. to 90.degree. C., carrying out a precondensation with 1 to 2 moles of formaldehyde and 0.5 to 1.5 moles of urea per mole of phenol units present in aqueous medium,(C) partially neutralizing the reaction mixture,(D) adding to the partially neutralized reaction mixture 0 to 0.5 mole of phenol per mole of phenol units present and then 0.1 to 0.8 mole of formaldehyde per mole of phenol units then present,(E) further condensing at from 40.

Abstract: The present invention relates to phenolic resin compositions and methods for making cured phenolic resin compositions. The phenolic resin compositions of this invention comprise an esterified phenolic compound and a base and optionally an unesterified phenolic resole resin. The composition cures in the presence of water or other polar solvent. The esterified phenolic compound contains at least one phenolic hydroxyl group or an esterified phenolic hydroxyl group and further contains at least one esterified methylol group positioned ortho or para to a phenolic hydroxyl group or an esterified phenolic group.The compounds find particular use in bonding refractory materials, such as sand, in the production of foundry moulds and cores and in treating subterranean formations. These composition have the advantage that cure can be obtained at room temperature without the use of strong alkali. The use of this system also prevents the release of alcohols during the saponification stage of the ester cure process.

Abstract: A composition and a process for bonding lignocellulosic material under heat and pressure is disclosed. According to the process, a curing agent is combined with a binder which is an alkaline phenol-formaldehyde resin. In one aspect the combination is by injection into a line carrying the binder to application apparatus, followed by in-line mixing of the curing agent and binder and application of the mixture to the lignocellulosic material. The lignocellulosic material is then compressed and the binder cured. The curing agent may be an ester, a lactone or an organic carbonate. The effect of the curing agent may be moderated with an aliphatic mono or polyhydric alcohol.

Abstract: Disclosed is a catalyst system which improves the cure time of acid-catalyzable resole resins while providing extended shelf life thereof. Broadly, the present invention includes a method for formulating an acid-catalyzed, non-aqueous resole resin composition and to the composition itself. The catalyst system comprises an acid catalyst and an oxidizing agent in an amount adequate for cure in at least about the same time that occurs by use of at least twice the amount of said acid catalyst alone. The shelf life of the catalyzed resole resin is greater with the inventive catalyst system than with an equivalent resole resin containing only the acid catalyst in twice the amount.

Abstract: Cyclic formals, other than trioxane, form macromers with an olefinically unsaturated alcohol which functions as a propagating species to form a macromer of polyformal having a molecular weight generally less than about 10,000. A cationically ring-openable ether may be used to provide a polyether spacer in the alkenyl alcohol so that the macromer of polyformal formed contains a polyether block. Thus, the polyformal macromer may have a acryloyl, allyl, or styryl head group. Macromers of polyformal block copolymers are formed sequentially by first forming the block of first formal and then without isolating the macromer so formed, sequentially polymerizing a second formal monomer to form the second formal block. A macromer of randon copolymer may be formed with one or more cyclic formals or a cyclic ether. Macromers of random copolymers may also be formed with formaldehyde or trioxane.

Abstract: An improved process for increasing the rate of the copolymerization of mixtures of polyphenolic compounds having more than two phenolic hydroxyl groups per molecule and bis-oxazolines comprising carrying out the copolymerization in the presence of a catalytic amount of a halohydrocarbon at a temperature in the range of from about 130.degree. C. to 150.degree. C. is described.

Abstract: Compositions have melting points below 100.degree. C. which are useful in the formation of resins by reaction with polyphenolic compounds consisting of a mixture of more than two compounds having the formula ##STR1## wherein A represents a cyclic or acyclic aliphatic or substituted cyclic or acyclic aliphatic moiety having from 1 to 20 carbon atoms or an aromatic mono- or multi-nuclear or aliphatic substituted aryl residue having from 6 to 20 carbon atoms,R independently represents H, CH.sub.3, CH.sub.2 CH.sub.3 or C.sub.6 H.sub.5,R.sup.1 independently represents H or CH.sub.3,R.sup.2 independently represents H or CH.sub.3, andx represents an integer from 0 to 2are described.

Abstract: A polymerizable thermosetting composition which is a flowable liquid at moderate temperatures which comprises a mixture of:(A) from about 75% to about 95% by weight of a mixture of:(1) from about 80% to about 20% by weight of a bisoxazoline and(2) from about 20% to about 80% by weight of a polyphenolic compound and(B) from about 5% to about 25% by weight of at least one member selected from the group consisting of a monooxazoline and a monooxazine,a method for forming thermoset products therefrom and the novel thermoset products resulting from said method are described.

Abstract: A hydrocarbon-soluble corrosion inhibitor composition comprising the reaction product obtained by the acid-catalyzed oligomerization of an alkylaniline and formaldehyde, wherein the alkylaniline has from 4 to 30 carbon atoms in the alkyl substituent. Also disclosed is a method of inhibiting corrosion of a corrodible metal utilizing said composition.

Abstract: A process for preparing copolymers of a mixture of a bis-oxazoline and a polyphenolic compound at improved rate of copolymerization by the inclusion of a catalytic amount of a carbonium ion salt of the formula Ph.sub.3 CX wherein Ph represents a phenyl group and X represents BF.sub.4, PF.sub.6, SbF.sub.6, AsF.sub.6, BPh.sub.4 or ClO.sub.4, is described.

Abstract: The process described herein involves the gradual addition of aqueous formaldehyde, containing 35-60 percent by weight of formaldehyde, to a phenol maintained at a temperature of 60.degree.-100.degree. C., preferably 70.degree.-90.degree. C., and at a reduced pressure of 11-26 inches of mercury in the presence of an alkaline catalyst. The rate of formaldehyde addition is such that the exothermic reaction aids in maintaining the stated temperature range and thereby simultaneously distills approximately all the water added with the formaldehyde and that formed by the condensation so that the volume of the reaction mass is maintained approximately constant. This constant volume allows efficient use of the equipment.

Abstract: A process comprising copolymerizing an oxazoline with a bis-or poly-phenolic compound in the presence of a catalyst which is a cationic complex of an alkali or an alkaline earth metal at a temperature in the range of from about 100.degree. to 200.degree. C. is described.

Abstract: Polymerizable compositions contain (A) a cationically polymerizable material, such as an epoxide resin, a phenoplast or a cyclic vinyl ether, (B) a hydroxy compound such as styreneallyl alcohol copolymer, and (c) an aromatic iodosyl salt of formula ##STR1## where R.sup.3 and R.sup.4, which may be the same or different, each represent a monovalent aromatic radical having from 4 to 25 carbon atoms, x denotes 1, 2 or 3, and Z.sup.x- denotes an x-valent anion of a protic acid.Suitable salts of formula II include diphenyliodosyl hexafluorophosphate and tetrafluoroborate. The compositions may be photopolymerized or they may be thermally polymerized in the presence, as catalyst for the iodosyl salt, of a salt or complex of a d-block transition metal, a stannous salt, an organic peroxide or an activated .alpha.-hydroxy compound.The compositions may be used as surface coatings and adhesives, and in the preparation of printing plates, printed circuits and reinforced composites.

Abstract: A polymeric material comprising a solid dispersion of a porous three-dimensional polymer with a pore diameter of 0.002 to 10 .mu.m and a permeability coefficient of from 2.times.10.sup.-7 to 2.times.10.sup.31 2 cm.multidot.sec.sup.-1. This material is produced by reacting formaldehyde with at least one monomer capable of forming, with formaldehyde, a polymer of a three-dimensional structure. The reaction is carried out in the presence of a polymerization catalyst in an aqueous medium at a pH of from 0.1 to 4, while maintaining the polymer concentration within the range of from 20 to 65% by mass. Thereafter the solution with the polymer is maintained for a period sufficient to form a porous polymer in the form a solid dispersion.

Abstract: An aqueous flocculant solution containing a tannin based polymer compound is produced which is stable and has a shelf life of at least 3-6 months before gelling. The solution is made by reacting at a temperature of from 150.degree.-200.degree. F. a tannin, an amino compound, and an aldehyde under slightly acidic conditions where the pH is less than 7 and where the molar ratio of the primary amine from the amino compound to the tannin repeating unit is from about 1.5:1 to 3.0:1. The intermediate viscosity of the reaction mixture is monitored until the reaction mixture has an intermediate viscosity within the range of the system key intermediate viscosity range. This system key intermediate viscosity range is previously determined for each reactant system to be employed. It is a narrow intermediate viscosity range that is experimentally determined which permits the resulting product to have a long shelf life.

Abstract: A method for a condensate of an aldehyde compound and a phenol compound, said method comprising dispersing a viscous condensate obtained by the reaction of an aldehyde compound with a phenol compound into cold water or hot water by the aid of a dispersing agent, and then solidifying said condensate.

Abstract: Condensation polymers prepared by reaction of a cyclic diol with a diether or aldehyde, or both, optionally with a branching agent, such as bis(4-hydroxycyclohexyl)propane with paraformaldehyde, or a diether such as methylene-dimethyl ether, or both, optionally with a branching agent such as a pentaethritol, in the presence of an acidic catalyst such as p-toluenesulfonic acid.

Abstract: A granular or powdery resin which is a condensation product of a phenol and an aldehyde and optionally a nitrogen-containing compound having at least two active hydrogens, said granular or powdery resin being characterized by(A) containing spherical primary particles and secondary particles resulting from the agglomeration of the primary particles, each of said particles having a particle diameter of 0.1 to 150 microns,(B) having such a size that at least 50% by weight thereof can pass through a 100 Tyler mesh sieve,(C) having a free phenol content, determined by liquid chromatography, of not more than 500 ppm, and(D) having a methanol solubility (S) of more than 20% by weight when about 10 g of the resin is heated under reflux in 500 ml of substantially anhydrous methanol.

Abstract: Polymerization of vinyl chloride in aqueous suspension using a polymerization reactor having adherently deposited on internal surfaces thereof a build-up suppressant coating comprising a product of build-up suppressant activity formable by (and preferably formed by) the condensation of an effective 1-naphthol (preferably 1-naphthol itself) and formaldehyde. The condensation is preferably effected in a base-catalyzed reaction; it may also (less preferably) be effected in an acid-catalyzed reaction. The coating product itself and a process for its production are also claimed.

Abstract: Compositions useful as friction particles comprised of tri- and/or tetrafunctional phenol, difunctional phenol, aldehyde, a protective colloid, and a reaction promoting compound. The friction particles are formulated into friction elements. A process for producing the friction particles in particulate form.

Abstract: A granular or powdery nitrogen-containing phenol-aldehyde copolymer resin which is a condensation product of a phenol, a nitrogen-containing compound having at least two active hydrogen atoms and an aldehyde, said granular or powdery resin being characterized by(A) containing spherical primary particles and secondary particles resulting from the agglomeration of the primary particles, each of said particles having a particle diameter of 0.1 to 100 microns,(B) having such a size that at least 50% by weight thereof can pass through a 150 Tyler mesh sieve,(C) having a free phenol content, determined by liquid chromatography, of not more than 50 ppm, and(D) having a D.sub.960-1020 /D.sub.1450-1500 ratio of from 0.1 to 2.0 in its infrared absorption spectrum.

Abstract: A granular or powdery resin which is a condensation product of a phenol and formaldehyde, said granular or powdery resin being characterized by(A) containing spherical primary particles and secondary particles resulting from the agglomeration of the primary particles, each of the particles having a particle diameter of 0.1 to 150 microns,(B) having such a size that at least 50% by weight thereof can pass through a 100 Tyler mesh sieve,(C) having a free phenol content, determined by liquid chromatography, of not more than 50 ppm,(D) having a D.sub.990-1015 /D.sub.1600 ratio of from 0.2 to 9.0 and a D.sub.890 /D.sub.1600 ratio of from 0.09 to 1.0 in its infrared absorption spectrum measured by a KBr tablet method, wherein D.sub.1600 represents the absorption intensity of an absorption peak at 1600 cm.sup.-1, D.sub.990-1015 represents the highest absorption intensity of absorption peaks at 990 to 1015 cm.sup.-1, and the D.sub.890 represents the absorption intensity of an absorption peak at 890 cm.sup.

Abstract: A fast curing shell molding composition having the tensile strength of a conventional novolac resin when cured contains a fast curing novolac resin comprising a methylene chained polyphenylol wherein a major portion of the methylene linkages are coupled to adjacent phenylol groups at the o-o' and p-p' position, wherein at least about 19% of the methylene linkages are coupled to adjacent phenylol groups at the o-o' portions, and wherein at least about 3% of the total number of methylene linkages are coupled to adjacent phenylol groups at the p-p' positions. The shell molding composition is produced from the fast curing novolac resin by uniformly coating refractory granules with the fast curing resin. The fast curing novolac resin can be prepared by blending a conventional novolac resin with a novolac resin having a large proportion of methylene linkages coupled to adjacent phenylol groups at the o-o' position.

Abstract: Disclosed is a color-developer for pressure-sensitive recording sheets, comprising a co-condensate of a reaction intermediate of a p-substituted phenol and a trifunctional or higher phenol, or a polyvalent metal salt of said co-condensate, said reaction intermediate being obtained by the reaction of said p-substituted phenol under acidic conditions with formaldehyde or a substance capable of generating formaldehyde.

Abstract: A process for the manufacture of condensation products of phenols and isobutyraldehyde by reacting the phenols and isobutyraldehyde at elevated temperature in a mole ratio of 0.5:1 to 1.5:1 in the presence of acid or compounds hydrolyzable to acids as catalysts, subsequent neutralization and removal of the resultant reaction water by distillation wherein the reaction products obtained in this manner are also subjected to a water-vapor distillation.

Abstract: A method of preparing a thermoplastic, water-soluble, phenolic aldehyde resin and the composition are provided to enhance the flexibility and resistance to compression fatigue breakage of glass fibers to which the resin has been applied. The method involves two steps. In the first step, the phenolic compound and the aldehyde are reacted to less than 100 percent completion in an amount so that the aldehyde to phenolic compound ratio is in the range of about 0.6 to about 1.5 and at an acidic pH and for a period of time equivalent to about 3 hours to about 10 hours when the temperature is in the range of about 55.degree. F. (13.degree. C.) to about 90.degree. F. (32.degree. C.) to produce a resinous mixture. In the second stage the pH of the reaction is adjusted within the range above about 7.0 to about 7.

Abstract: An adhesive consisting comprising an alkoxyphenol derivative/resorcin derivative/formaldehyde cocondensate has a high adhesive strength and can bond firmly polyester fibrous material with rubber.

Abstract: A process for preparing a resorcinol copolymer, comprising at least one specific phenol with formaldehyde at a certain mole ratio to obtain a resol-type precondensate containing 1 to 30% of residual unreacted formaldehyde and then adding said resol-type precondensate to a mixture of an acid catalyst and at least one resorcinol to effect co-condensation. The obtained copolymer is useful for an adhesive for polyester fiber and rubber.

Abstract: An adhesive comprising a cocondensate of formaldehyde with m-alkylphenol or its derivative and alkylresorcin is excellent in the adhesion, heat resistance and flexibility and can bond firmly polyester fibrous material with rubber.

Abstract: Carboxylate salts, prepared by a Mannich reaction and useful in the preparation of water-borne coatings, have the general formula ##STR1## where R.sup.1 represents an aliphatic, aromatic, or araliphatic divalent group which may contain a further --COO.sup.- M.sup.+ ; R.sup.2 represents --H, --CH(R.sup.3)N(R.sup.10)R.sup.1 COO.sup.- M.sup.+, or alkyl which may be substituted by --COO.sup.- M.sup.+, --CH(R.sup.3)OH, or --CH(R.sup.3)OR.sup.8, R.sup.1 and R.sup.2 containing together not more than one --COO.sup.- M.sup.+ ; R.sup.3 represents --H or alkyl; each R.sup.4 represents --H, halogen, alkyl, or alkenyl; R.sup.5 represents --H, halogen, alkyl, alkenyl, or a group --CH(R.sup.3)OH, --CH(R.sup.3)OR.sup.8, or --CHR.sup.3 --NR.sup.2 --R.sup.1 --COO.sup.- M.sup.+ ; either R.sup.6 represents --H and R.sup.7 represents the residue of a polyepoxide, preferably of average mol. wt. 1000-5000, or R.sup.6 represents a covalent bond linked to the group R.sup.7, and R.sup.

Abstract: A process for the preparation of synthetic resins based on resorcinol compounds which comprises reacting a resorcinol pitch which is obtained in the manufacture of resorcinol from benzenedisulfonic acid in at least one step with an oxo-compound selected from aldehydes, ketones and compounds based on or splitting off at least one of these substances, and the use of the products as binders for abrasive articles.

Abstract: A process for producing a phenolic resin comprising condensing a phenol component and an aldehyde component, characterized in that the phenol component comprises (high-molecular-weight phenolic compounds which are left after bisphenol A-containing by-products formed in the production of bisphenol A by condensing acetone and phenol in the presence of an acid catalyst are treated at a high temperature of at least 150.degree. C. in the presence of an alkaline catalyst to remove low-boiling components therefrom.

Abstract: Polymerization method utilizing a three-phase system: water-in-oil-in-water or oil-in-water-in-oil comprising the steps (a) adding the monomer material to be polymerized into the innermost water or oil phase; (b) adding, with mechanical agitation, the product of Step a to the middle oil or water phase, said phase containing appropriate surfactant, whereby an emulsion is formed; (c) adding, with mechanical agitation, the emulsion product of Step b to the outermost water or oil phase, said phase containing appropriate surfactant, wherein polymerization proceeds in the innermost water or oil phase until complete.

Abstract: Binders for foundry core sands and the like comprising furfuryl alcohol and an aromatic dialdehyde and optionally an aromatic alcohol.

Abstract: Binders for foundry core sand and other binder applications are produced from the tars resulting from production of bisphenol A.

Abstract: A method for the production of a powdery, free-flowing phenol/formaldehyde resin is disclosed wherein a polyvalent cationic precipitant is added to the resin emulsion produced, the precipitate is filtered, washed with water and dried.

Abstract: A method of preparing a thermoplastic, long-chain water-soluble, phenolic formaldehyde resin and the composition are provided to enhance the flexibility and resistance to compression fatigue breakage of glass fibers to which the resin has been applied. The method involves two steps. In the first step, the phenolic compound and the formaldehyde are reacted to less than 100 percent completion in an amount so that the formaldehyde to resorcinol ratio is in the range of about 0.6 to about 2.0 and at an acidic pH and for a period of time equivalent to about 1 hour to about 20 hours when the temperature is in the range of about 30.degree. F.(-31 1.1.degree. C.) to about 122.degree. F. (50.degree. C.) to produce a resinous mixture having a predominant amount of trimer polymer along with minor amounts of dimer and higher oligomer polymers and along with unreacted phenolic compound and aldehyde. In the second stage the pH of the reaction is adjusted within the range above of about 7.0 to about 7.

Abstract: A method of producing essentially monomeric etherified formaldehyde condensates with a bisphenol having a plurality of formaldehyde-reactive sites is disclosed in which the bisphenol is reacted with at least about 2 moles of formaldehyde per mole of bisphenol in solution in etherifying alcohol in the presence of an insoluble strong acid cation exchange resin. The reaction is carried out at a reaction temperature of from about 30.degree. C. to about 100.degree. C. to simultaneously provide the desired methylolation and etherification without introducing soluble ionic contaminants.

Abstract: Improved friction elements suited for use for example in an automotive or similar brake or in a clutch are provided by employing therein as a binder the reaction product of phenol, formaldehyde, and monoalkylphenol having from 4 to about 20 carbon atoms in the alkyl group. The mole ratio range of phenol:alkylphenol:formaldehyde is about 2:1-5:1-7 and the number of moles of phenol and alkylphenol combined exceeds the number of moles of formaldehyde. An improved method of making friction elements is also provided which uses such binder.

Abstract: Self-curing or curable materials are obtained from the distillation residues of coal hydrogenation by condensing a residue of this type having a softening point of 30.degree. to 54.degree. C. in a first stage with a mono- or dihydroxybenzene and/or a methylhydroxybenzene and/or an ethylene substituted benzene. These reactants are used at a ratio of residue to benzene derivative between 1:1 and 2:1 and the reaction is carried out in the presence of acid at a pH of 1 to 2 and at a temperature of 90.degree. to 100.degree. C. In a second stage the thus obtained reaction product is then further reacted at about the same temperature with an aldehyde. As a result a novolak-type resin is obtained. The invention permits the making of inexpensive self-curing or curable materials with properties similar to those of phenolic acids. Besides, the invention also provides an outlet for the high boiling residue of the extractive coal hydrogenation which otherwise had little use.

Abstract: Phenolic novolak resins are described which are structurally characterized as having from about 55% to about 90% of the available theoretical paraphenyl linkages in the resin chain bridged to a phenyl group. The resin compositions of this invention provide extended resin stability at relatively low temperatures without significant adverse affect on the cure speed at the molding temperature. The resins are especially suited for use in runnerless injection or cold manifold molding processes, but can also be used in transfer, compression and injection molding processes.

Abstract: Phenolic novolak resins are described which provide extended resin stability at relatively low temperatures without significant adverse affect on the cure speed at the molding temperature. The resins are especially suited for use in runnerless injection or cold manifold molding processes, but can also be used in transfer, compression and injection molding processes.

Abstract: A process for producing an acid agent which comprises reaction of sulphonated phenol and formaldehyde in an "ideal" displacement reactor at a temperature within the range of from 50.degree. to 120.degree. C. at a constant molar ratio of said components. The reaction may be carried out in the presence of additives such as urea or orthophosphoric acid.The process according to the present invention has an increased productivity at reduced power and labor inputs as compared to the prior art processes.

Abstract: Particulate resoles are produced by reacting a phenol, formaldehyde, and an amine in an aqueous medium containing a protective colloid, to produce an aqueous suspension of a particulate resole, and recovering the particulate resole from said suspension.

Abstract: The process according to the present invention comprises a continuous polycondensation of the anthracene fraction of coal tar boiling within the range of from 270.degree. C. to 350.degree. C., phenol and formaldehyde at a weight ratio between the components of 1:3-4:1-1.2 in the presence of 0.5 to 1.2% by weight of an acidic catalyst at a supply rate of a mixture of said components of 500-550 g/hr.The present invention makes it possible to continuously prepare the desired product, whereby its output from a unit production volume is substantially increased. The product has a high curing rate and a high coke value.

Abstract: An ink composition is provided which is suitable for use on plastic, bare metal, for example, tinplate or aluminum as well as on such metals having organic coatings applied to surfaces thereof. The inks are suitable for use in contact printers or in jet ink printing techniques and apparatus. The ink compositions are thermotropic, i.e. they change color in the presence of water or steam at elevated temperature and are useful as sterilization or pasteurization indicators. The inks comprise essentially a binder resin component, or mixture of such resin components, an alcohol solvent and a combination of dyes which produce a visible and permanent color change in the presence of water or steam at elevated temperatures.