US005326739A United States Patent (19) 11) Patent Number: 5,326,739 Tanabe et al. 45) Date of Patent: Jul. 5, 1994 54 PROCESS FOR PRODUCING 3,5-DI(a-METHYLBENZYL)SALICYLIC FOREIGN PATENT DOCUMENTS ACID DERIVATIVE, AND USE OF 0218553 4/1987 European Pat. Off...... 503/210 POLY WALENT-METAL-MODIFIED 0219457 4/1987 European Pat. Off...... 503/210 PRODUCT THEREOF AS COLOR 0264051 4/1988 European Pat. Off...... 503/20 DEVELOPER 2696.19 7/1989 Fed. Rep. of Germany ...... 503/210 49-10856 3/1974 Japan ...... 503/20 75) Inventors: Yoshimitsu Tanabe, Yokohama; 61-26772 5/1986 Japan ...... 503/210 Keizaburo Yamaguchi, Chiba; 61-100493 5/1986 Japan ...... 503/20 Akihiro Yamaguchi, Kamakura, all of 62-96449 5/1987 Japan ...... 503/20 Japan 2-91042 9/1988 Japan ...... 503/210 1-133780 9/1988 Japan ...... 503/210 73 Assignee: Mitsui Toatsu Chemicals, 2-91043 3/1990 Japan ...... 503/210 Incorporated, Tokyo, Japan OTHER PUBLICATIONS Appl. No.: 21 134,719 English Abstract of JP-A-2 091 042. 22 Filed: Oct. 12, 1993 Chemical Abstracts, vol. 93, Aug. 18, 1990, 93:7130h. Chemical Abstracts, vol. 79, No. 3, Jul. 23, 1973, Related U.S. Application Data 79:1830s. (62) Division of Ser. No. 740,386, Aug. 5, 1992, Pat. No. Primary Examiner-B. Hamilton Hess 5,274,150. Attorney, Agent, or Firm-Millen, White, Zelano & 30 Foreign Application Priority Data Branigan Aug. 6, 1990 (JP) Japan ...... 2-2067.11 57 ABSTRACT 51) Int. Cl...... B41M 5/035; B41M 5/38 A color-developing sheet using, as a color developer, 52) U.S.C...... 503/210; 427/150; polyvalent-metal-modified products of 503/211; 503/212; 503/216; 503/225 compounds composed mainly of a 3,5-di(a-methylben 58 Field of Search ...... 427/150; 503/210-212, zyl)salicylic acid derivative obtained by reacting a sali 503/216, 225 cylic acid ester with an a-methylbenzyl halide in the (56) References Cited presence of an acid catalyst and hydrolyzing the reac U.S. PATENT DOCUMENTS tion product. Said color-developing sheet has excellent color deve 4,745,203 5/1988 Nachbur ...... 562/468 4,748,259 5/1988 Nachbur. ... 556/132 lopability at low temperatures and gives a color of ex 4,754,063 6/1988 Nachbur. ... 562/468 cellent water resistance. 4,879,368 11/1989 Botta et al...... 528/397 4,952,648 8/1990 Yamaguchi et al...... 52.5/539 15 Claims, 3 Drawing Sheets n CO Y o

or r co o U.S. Patent July 5, 1994 Sheet 1 of 3 5,326,739

F I. G.1

i s U.S. Patent July 5, 1994 Sheet 2 of 3 5,326,739

F I G. 2

LZ78

cHOLS U.S. Patent July 5, 1994 Sheet 3 of 3 5,326,739

F I G.3

d'OLS 5,326,739 1. 2 (ii) In order to overcome such a problem of high PROCESS FOR PRODUCING production cost, it was attempted to produce a similar 3,5-DI(o-METHYLBENZYL)SALICYLIC ACID salicylic acid compound by, for example, subjecting DERIVATIVE, AND USE OF salicylic acid or a salicylic acid ester to alkylation. POLYVALENT-METAL-MODIFIED PRODUCT 5 It is known to react 1 mole of salicylic acid with 2 THEREOF AS COLOR DEVELOPER moles of 1-phenylethanol to obtain 5-a-methyl-4-(a- methyl-benzyl)-benzyl)salicylic acid or a mixture of SPECIFICATION 5-a-methyl-4-(a-methylbenzyl)-benzylsalicylic acid This application is a division of Ser. No. 07/740,386, and 3,5-di(a-methylbenzyl)salicylic acid Japanese Pa filed Aug. 5, 1991, now U.S. Pat. No. 5,274,150. 10 tent Application Kokai (Laid-Open) Nos. 100493/1986 and 96449/1987). This production process has various BACKGROUND OF THE INVENTION problems. The substituted salicylic acid obtained is a (1) Field of the Invention mixture of various compounds. Therefore, a monosub The present invention relates to a novel process for stituted salicylic acid or a mixture of a monosubstituted producing a 3,5-di(a-methylbenzyl)salicylic acid deriv 5 salicylic acid and a disubstituted salicylic acid is isolated ative useful as a color developer for pressure-sensitive in the form of a metal salt by a complicated procedure; copying paper or heat-sensitive paper, as well as to a when the metal salt of the mixture is used as a color color developer containing a polyvalent-metal-modified developer for pressure-sensitive copying paper, the product of the 3,5-di(a-nethylbenzyl)salicylic acid de resulting color-developing paper has insufficient repro rivative. 20 ducibility in properties such as color developability, (2) Description of the Prior Art storage stability and the like. Salicylic acid type compounds, when used as a color (iii) It was proposed to react salicylic acid with a developer for pressure-sensitive paper or heat-sensitive styrene compound in the presence of an aliphatic car paper, are generally excellent in clearness of developed boxylic acid using an organic sulfonic acid or an inor color image, storage stability, etc. In the pressure-sensi 25 ganic acid as a catalyst, to produce a disubstituted sali tive paper using a salicylic acid type compound as a cylic acid Japanese Patent Application Kokai (Laid color developer, however, there are problems of (a) Open) No. 91043/1990). slow color development due to the insufficient compati This production process is not advantageous industri bility of said compound with a capsule oil used for ally because the reaction is carried out at 90°-130 C. 30 using an aliphatic carboxylic acid (e.g. acetic acid, pro dissolution of a color former and (b) insufficient water pionic acid) and sulfuric acid or methanesulfonic acid in resistance of the developed color image, i.e. disappear combination, with the acid used in an amount of 50% by ance of said image by dissolution in water. Various weight or more based on the salicylic acid and accord attempts have been made in order to alleviate these ingly the process has a problem of disposing a large problems. For example, it has been proposed to intro 35 amount of the waste acid. In this process, the reaction duce an aromatic substituent into the salicylic acid skel product is, for example, a mixture of 3,5-di(a-methyl etO. benzyl)salicylic acid with 3-a-methylbenzyl-5-(1,3- The introduction of an aromatic substituent (e.g. a diphenylbutyl)salicylic acid and 3-(1,3-diphenylbutyl)- benzyl group) into, in particular, the 3- and 5-positions 5-a-methylbenzylsalicylic acid. When such a reaction of the salicylic acid skeleton is effective. A color product is used as a color developer for pressure-sensi developing sheet coated with a color developer consist tive paper, the resulting color-developing paper has the ing of, in particular, a polyvalent-metal-modified prod same problems as in the above (ii). uct of a salicylic acid compound with a benzyl group (iv) With regard to the alkylation of an alkyl salicyl having a methyl group at the a-position, shows out ate, it is known to react, for example, standing color developability and has excellent resis 45 with styrene in the presence of an alkanesulfonic acid to tance to yellowing when exposed to sunlight, excellent produce methyl 3,5-di(a-methylbenzyl)salicylate Japa stability of the developed color image and excellent nese Patent Publication No. 26772/1986. In this pro resistance to yellowing by nitrogen oxides in air; there duction process using styrene, various styrene polymers fore, the sheet is very advantageous in handling and and other by-products are formed. This process, simi storage. The above color developer, however, has 50 larly to the process for production of salicylic acid ester drawbacks in that its slight solubility in water causes the resin disclosed in Japanese Patent Application Kokai(- disappearance of developed color image by water and Laid-Open) No. 133780/1989 by the present inventors, its high melting point (190-220 C) makes slow the is unable to suppress said reactions (resinification) even rate of its dissolution in a capsule oil containing a color if the catalyst, the molar ratio of salicylic acid ester and precursor. This leads to inferior initial-stage color deve 55 styrene, the reaction temperature, etc. are varied. lopability at low temperatures and limited use in cold In Comparative Example 1 (described later) which districts. (i) It is known to produce a 3,5-disubstituted was conducted for confirmation of the Example 1 of the salicylic acid from a corresponding substituted phenol above Japanese Patent Publication No. 26772/1986, the and carbon dioxide according to the Kolbe-Schmitt selectivity of methyl 3,5-di(a-methylbenzyl)salicylate reaction. For example, it is disclosed in Japanese Patent was 43%. This is because not only a monosubstituted Publication No. 10856/1974 that 3,5-di(a,a-dimethyl compound and a trisubstituted compound but also sty benzyl)salicylic acid is produced from 2,4-di(a,a-dime rene polymers, a dimer adduct, etc. are formed. More thylbenzyl)phenol obtained from phenol and a-meth over, the amount of alkanesulfonic acid used is large. ylstyrene. This production process, however, generally Therefore, the above process is not advantageous. incurs a high production cost because the reaction steps 65 are many, the yield is low, and the reaction for intro SUMMARY OF THE INVENTION ducing a carboxyl group is carried out under high tem The objects of the present invention are to develop an perature and high pressure conditions. economical process for producing a 3,5-di(a-methyl 5,326,739 3 4 benzyl)salicylic acid derivative which can be used as a tive, which comprises reacting a salicylic acid ester color developer having excellent color developability represented by the general formula (I) and giving a developed color image with excellent resis tance to yellowing by light, and to provide a color OH (I) developer using said derivative and a color developer 5 composition significantly improved in color developa COOR bility at low temperatures and in water resistance of developed color image. The above objects are achieved by a process comprising reacting a salicylic acid ester with an a-methylbenzyl halide in the presence of an 10 acid catalyst to form a 3,5-di(a-methylbenzyl)salicylic wherein R1 represents an alkyl group, an aralkyl group acid ester and then hydrolyzing it to produce a 3,5-di(d- or a cycloalkyl group each having at most 12 carbon methylbenzyl)salicylic acid derivative. atoms, with an a-methylbenzyl halide represented by In this case, when the reaction mixture is subjected, the general formula (II) prior to being hydrolyzed, to vacuum distillation to 15 isolate the 3,5-di(a-methylbenzyl)salicylic acid ester, CH3 (II) the 3,5-di(a-methylbenzyl)salicylic acid derivative can CH-X be obtained at a purity of 99% or higher. The present inventors also found that the above ob jects can further be achieved by reacting a salicylic acid 20 ester with an a-methylbenzyl halide in the presence of an acid catalyst, then hydrolyzing the reaction product to produce an a-methylbenzyl-substituted salicylic acid R2 R3 derivative composition containing 60-90% by weight of a 3,5-di(a-methylbenzyl)salicylic acid derivative, 25 wherein R2 and R3 each represent a hydrogen atom or converting the composition to a polyvalent-metal-modi an alkyl group of 1-4 carbon atoms, and X represents a fied product, and using the polyvalent-metal-modified halogen atom, in the presence of an acid catalyst and product as a color developer. hydrolyzing the resulting 3,5-di(a-methylbenzyl)salicy The process of the present invention can produce a lic acid ester, (2) a polyvalent-metal-modified product 3,5-di(a-methylbenzyl)salicylic acid derivative from 30 of the a-methylbenzyl-substituted salicylic acid deriva inexpensive starting materials in a simple procedure and tive composition containing 60-90% by weight of a accordingly is preferable for industrial application. 3,5-di(a-methylbenzyl)salicylic acid derivative, ob Further, the color-developing sheet using a polyva tained by the above process, and (3) a color-developing lent-metal-modified product of an a-methylbenzyl-sub sheet using the polyvalent-metal-modified product as a stituted salicylic acid derivative composition produced 35 color developer. according to the present invention, composed mainly of The salicylic acid ester used in the present invention a 3,5-di(a-methylbenzyl)salicylic acid derivative, has includes methyl salicylate, , n-propyl excellent color developability at low temperatures and salicylate, isopropyl salicylate, isoamyl salicylate, ter accordingly is preferably used at low temperatures toctyl salicylate, nonyl salicylate, dodecyl salicylate, (conventional color-developing sheets of similar tech 40 cyclohexyl salicylate, , a-methylbenzyl nique have had insufficient color developability at low salicylate, etc. However, the salicylic acid ester is not temperatures). Also, the color-developing sheet is free restricted to these compounds. Methyl salicylate and from a problem of disappearance of developed color ethyl salicylate are preferable industrially. image by water. Therefore, the color-developing sheet In the a-methylbenzyl halide used in the present in can be used stably in the fields which have restricted the 45 vention, the halogen includes chlorine and bromine. use of conventional color-developing sheets of similar Chlorine is preferable. Accordingly, the a-methylben technique. zyl halide includes a-methylbenzyl chloride, o-methyl a-methylbenzyl chloride, p-methyl-a-methylbenzyl BRIEF DESCRIPTION OF THE DRAWINGS chloride, In-methyl-a-methylbenzyl chloride, o-ethyl FIG. 1 shows an example of the analytical results 50 a-methylbenzyl chloride, p-ethyl-a-methylbenzyl chlo when the 3,5-di(a-methylbenzyl)salicylic acid isolated ride, p-isopropyl-a-methylbenzyl chloride, 2,3-dimeth according to the present process has been subjected to yi-a-methylbenzyl chloride, 2,4-dimethyl-a-methylben high-performance liquid chromatography. zyl chloride, 2,5-dimethyl-a-methylbenzyl chloride and FIG. 2 shows an example of the analytical results 3,4-dimethyl-a-methylbenzyl chloride. However, the when the a-methylbenzyl-substituted salicylic acid de 55 a-methylbenzyl halide is not restricted to these con rivative composition obtained according to the present pounds. Of these compounds, a-methylbenzyl chloride process has been subjected to high-performance liquid and p-methyl-a-methylbenzyl chloride are preferable. chromatography. The amount of the a-methylbenzyl halide used in the FIG. 3 shows an example of the analytical results process of the present invention is preferably 1.5-3 when the 3,5-di(o-methylbenzyl)salicylic acid-contain moles per mole of the salicylic acid ester represented by ing oily substance obtained according to a conventional the general formula (). When the amount is less than process has been subjected to high-performance liquid 1.5 moles or more than 3 moles, the yield of a 3,5-di(a- chromatography. methylbenzyl)salicylic acid ester as a main precursor is low. DETAILED DESCRIPTION OF THE 65 As the acid catalyst used in the present process, there INVENTION can be mentioned Lewis acids such as ferric chloride, The present invention provides (1) a process for pro zinc chloride, aluminum chloride, stannic chloride, tita ducing a 3,5-di(a-methylbenzyl)salicylic acid deriva nium tetrachloride and boron trifluoride, and superacids 5,326,739 5 6 such as perfluoroalkanesulfonic acid (e.g. trifluorome none, N-methylpyrrolidone and hexamethylphosphoric thanesulfonic acid) and perfluoroalkanesulfonic acid triamide, and glycols such as ethylene glycol, polyeth resin (e.g. Nafion H (trademark of Du Pont). Of these, ylene glycol dialkyl ether, 2-methoxyethanol and 2 zinc chloride is particularly preferable. ethoxyethanol. There may further be used solvents The amount of the catalyst used is 0.05-200 mole % having no miscibility with water, such as toluene, xy and, in view of the economy, preferably 0.1-100 mole lene, monochlorobenzene, 1,2-dichloroethane and 1,1,2- % based on the salicylic acid ester. trichloroethane. The amount of the solvent used is suffi The reaction temperature is 0°-180° C., preferably ciently 0.5-10 (volume/weight) times the total amount 5'-80 C., more preferably 10-40°C. The reaction time of the raw materials. is ordinarily 1-120 hours. 10 The reaction mixture after the hydrolysis contains a In the reaction of the salicylic acid ester with the reaction product composed of 60-90% by weight of a a-methylbenzyl halide, a solvent may be used as neces 3,5-di(a-methylbenzyl)salicylic acid derivative, 0-40% sary. As the solvent, there can be used those inactive to by weight of a 3-or 5-(a-methylbenzyl)salicylic acid the reaction, for example, halogenated hydrocarbons derivative (hereinafter abbreviated to a monosubstitu such as 1,2-dichloroethane and 1,1,2-trichloroethane, 5 ted salicylic acid derivative) and 0-40% by weight of a and organic acids such as acetic acid and propionic acid. salicylic acid compound formed by the reaction of said The amount of the solvent when used is desirably not 3,5-di(a-methylbenzyl)salicylic acid derivative with an more than 30 (volume/weight) times the total amount a-methylbenzyl group (said salicylic acid compound is of the raw materials in view of the economy. hereinafter abbreviated to a trisubstituted salicylic acid In the present invention, the reaction of the salicylic 20 derivative), in which reaction product said three com acid ester with the a-methylbenzyl halide is generally ponents occupy 95% by weight or more of the total and carried out by feeding necessary amounts of the sali the remainder is occupied by aromatic salicylic acid cylic acid ester of the general formula (I), the a-methyl resins and oligomers of a-methylbenzyl halide. Since benzyl halide of the general formula (II) and the cata the hydrolysis is carried out substantially quantitatively, lyst at one time and reacting them at a predetermined 25 the proportions of the corresponding components of the temperature, or by feeding the salicylic acid ester and ester form before the hydrolysis are thought to be about the catalyst first and then adding the a-methylbenzyl the same as above. halide dropwise to react them. The above reaction product which is composed The end point of the reaction can be determined by mainly of a 3,5-di(a-methylbenzyl)salicylic acid deriva examining the decrease of the raw materials, i.e. the 30 tive and which may further contain mono- and/or tri salicylic acid ester and the a-methylbenzyl halide by substituted salicylic acid derivative, is referred, in the means of high-performance liquid chromatography. present invention, to an a-methylbenzyl-substituted The hydrolysis is carried out according to an ordi salicylic acid derivative composition. nary method using an aqueous acid or alkali solution. In order to obtain a 3,5-dia-methylbenzyl)salicylic The hydrolysis using an aqueous acid solution is carried 35 acid derivative of high purity (99% or higher), the out using water and an acid, i.e. a mineral acid (e.g. reaction product before hydrolysis is subjected to vac hydrochloric acid, sulfuric acid), a combination of sul uum distillation to separate a 3,5-di(a-methylbenzyl)- furic acid and acetic acid, an organic sulfonic acid (e.g. salicylic acid ester and the ester is hydrolyzed. benzenesulfonic acid, p-toluenesulfonic acid, chloro This production process is inexpensive as compared benzenesulfonic acid, methanesulfonic acid), a Lewis with the conventionally known process using phenol as acid (e.g. aluminum chloride, zinc chloride, stannic a raw material and has a high selectivity as compared chloride), or a superacid (e.g. trifluoromethanesulfonic with the process using a salicylic acid ester and a sty acid, Nafion H). rene compound; therefore, it is a very advantageous The hydrolysis using an aqueous alkali solution is process in industrial application. generally carried out using water and sodium hydroxide 45 In this process, if the salicylic acid ester as a raw or potassium hydroxide. material is replaced by salicylic acid, the reactivity is The ratio of the acid or alkali and water can be se low owing to the presence of an electron-attractive lected freely but is generally 1:100 to 99:1, preferably carboxyl group and a reaction temperature higher than 5:95 to 95:5 by weight. in the present invention is required. Under such condi The amount of the acid or alkali used in the hydroly 50 tions, the selectivity of a disubstituted salicylic acid sis can be any amount relative to the amount of the derivative is as low as 40-50%. salicylic acid ester as a raw material. However, the In order to obtain a reaction product from the reac amount of the acid is generally 0.05-30 moles per mole tion mixture after hydrolysis, the reaction mixture is of the salicylic acid ester depending upon the intensity neutralized and, when the precipitation of crystals is of the acid, and the amount of the alkali is an equivalent 55 over, the crystals are isolated to obtain the reaction to 30 moles. product. When the reaction product is dissolved in the The reaction temperature is 50-200 C., preferably solvent used, the solvent is removed by distillation or 80-160 C. The reaction time is 1-50 hours. the reaction mixture is added to water, to obtain the In order to shorten the reaction time, it is possible to reaction product as crystals. add, as a reaction accelerator, a phase-transfer catalyst In some cases, it is possible to carry out recrystalliza such as quaternary phosphonium salt, crown ether, tion using an appropriate solvent to obtain crystals. The cryptate or polyethylene glycol. degree of progress of reaction or the purity of isolated The hydrolysis reaction is carried out ordinarily product can be determined by high-performance liquid using no organic solvent, but may use an organic sol chromatography. vent. As such an organic solvent, there may be used 65 The following is a description of the production of a aprotic polar solvents such as N-methylformamide, polyvalent-metal-modified product of the 3,5-di(a- N,N-dimethylformanide, N,N-dimethylacetamide, di methyl-benzyl)salicylic acid derivative or the a-methyl methyl sulfoxide, sulfolane, 1,3-dimethyl-2-inidazolidi benzyl-substituted salicylic acid derivative composition 5,326,739 7 8 (hereinafter the salicylic acid derivative and the sali ing, the proportion of the color developer component is cylic acid derivative composition are generically re desirably 10-70% based on the total solid content. ferred to simply as salicylic acid compound). When the proportion is less than 10%, insufficient color The polyvalent-metal-modified product is produced development is obtained. When the proportion is more by reacting an alkali metal salt of the salicylic acid com than 70%, the resulting color-developing sheet has de pound with a water-soluble polyvalent metal salt in graded surface properties. The amount of the coating water or in a solvent in which the two metal salts are applied is 0.5 g/m2, preferably 1-10 g/m2 in terms of soluble. dry weight The salicylic acid compound is dispersed in an aque The present invention is at least hereinafter described ous solution, an alcohol solution or an aqueous alcohol 10 in detail with reference to Examples. solution each containing a hydroxide, carbonate or Using each of the products obtained in Examples and alkoxide of an alkali metal in an amount at least equiva Comparative Examples as a color developer, color lent to the carboxyl group of the salicylic acid com developing sheets for pressure-sensitive copying were pound, and is dissolved therein at 0-100° C.; to the prepared as follows and these sheets were measured for resulting solution is added a water-soluble polyvalent 15 properties according to the following methods: The metal salt as is or in the form of an aqueous solution, an results of the property measurements are shown in alcohol solution or an aqueous alcohol solution; a reac Table 1 and Table 2. tion is carried out at 0-100° C. to obtain a polyvalent 1. Preparation of color-developing sheet metal salt of the salicylic acid compound as a precipi Using each of the metal-modified products of sali tate. It is desirable to react the water soluble polyvalent cylic acid compounds, obtained in Examples 2, 5, 6, 7 metal salt of about 0.5-1 equivalent to the carboxyl and 8 (described later), as a color developer, their sus group of the salicylic acid compound. pensions having the following formulation were pre The metal of the polyvalent-metal-modified product pared by means of a sand grinding mill. used in the present invention includes metals excluding alkali metals such as lithium, sodium and potassium. As 25 Color developer 6 parts by weight preferable polyvalent metals, there can be mentioned Aqueous solution containing 3 parts by weight calcium, magnesiums, aluminum, copper, zinc, tin, bari polyvinyl alcohol (Kurare #117) ums, cobalt and nickel. Of these, zinc is particularly Water 22.5 parts by weight useful. The thus obtained polyvalent-metal-modified prod 30 uct of the salicylic acid compound exhibits excellent Using each of the suspensions, coatings having the properties when used as a color developer. In using the following formulation were prepared. polyvalent-metal-modified product as a color devel oper, it is ground by a grinder, for example, a sand Suspension 10 parts by weight grinding mill so as to have an appropriate particle size. 35 Light calcium carbonate 10 parts by weight In actual use, the ground polyvalent-metal-modified Starch 0.8 part by weight product is suspended or dissolved in a solvent to con Synthetic rubber latex 0.8 part by weight vert into a desired form. It is possible to use the polyva Water 32.5 parts by weight lent-metal-modified product in combination with a known color developer such as inorganic solid acid Each of the coatings was coated on a high-quality (e.g. activated clay), organic polymer (e.g. phenol paper so that the coated amount as dried became 5.0-5.5 fomaldehyde resin) or other aromatic carboxylic acid g/m2, and dried to obtain color-developing sheets. metal salt. It is also possible to use the polyvalent-metal 2. Color-developing speed and developed color den modified product in combination with at least one ox sity (conducted in air-conditioned rooms of 5 C. and ide, hydroxide or carbonate of polyvalent metals se 45 60% R.H. and 20° C. and 65% RH.) lected from the group consisting of zinc, magnesium, A sample color-developing sheet coated with an aluminum, lead, titanium, calcium, cobalt, nickel, man aqueous coating was contacted with a blue-color ganese and barium. developing sheet on the market NW-40T (trade name), The preparation of a color-developing sheet used for a product of Jujo Paper Co., Ltd.) containing Crystal pressure-sensitive copying from the color developer of 50 Violet Lactone (CVL) as a main pressure-sensitive the present invention can be carried out, for example, color precursor, in such a way that the coated sides of by (1) a method wherein an aqueous coating is prepared the two sheets faced each other. They were typed by an using an aqueous suspension of the polyvalent-metal electronic typewriter to develop a color. modified product and it is coated on a substrate such as The developed color was measured for density one paper or the like, (2) a method wherein a paper is manu 55 minute and 30 seconds after the typing and 24 hours factured in the presence of the polyvalent-metal-modi after the typing, and the densities were each expressed fied product, and (3) a method wherein a coating is as Y value. prepared using a solution or suspension of the polyva 3. Light fastness of developed color image lent-metal-modified product in an organic solvent and it A sample color-developing sheet, which had been is coated on a substrate. 60 subjected to color development in the manner described In order to form, by coating, a color developer layer in the above 2, was exposed to light for 2 hours (and for on a substrate such as paper or the like, it is desirable 4 hours) in a carbon arc fade meter (manufactured by that the color developer have an appropriate viscosity Suga Testing Machine Co., Ltd.). After the exposure, and appropriate coatability. Therefore, the above aque the reflectance of the developed color image was mea ous suspension or the above solution or suspension in 65 sured by X-80 Color Difference Meter, and expressed as solvent is mixed with kaolin, clay, calcium carbonate, Y value. starch and synthetic or natural latex to prepare a coat The smaller the Y value and the smaller its difference ing of appropriate viscosity and coatability. In the coat from the Y value before the test, the less the fading of 9 5,326,739 10 the developed color image by light and the more prefer of water was added. Stirring was carried out at 60-70 able the color image. C. for 0.5 hour and then the mixture was allowed to 4. Plasticizer resistance stand until it separated into two layers, i.e. an organic A dioctyl phthalate (DOP) microcapsule coated layer and an aqueous layer (a lower layer). The lower paper sheet was prepared by forming microcapsules, aqueous layer was removed, and the organic layer was which contained DOP as a core substance, had an aver subjected to distillation to remove the solvent. The age size of 5.0 m, and were equipped with melamine residue was subjected to high-performance liquid chro formaldehyde resin capsule walls, adding thereto a matography (HLC) and found to consist of 3% of small amount of a starch-type liquid binder to obtain a methyl ester of monosubstituted salicylic acid, 89.5% of coating solution, applying the coating solution onto a 10 methyl ester of disubstituted salicylic acid and 7.5% of high-quality paper by an air-knife coater so that the methyl ester of trisubstituted salicylic acid. The residue coated amount as dried became 5 g/m, and then drying was then subjected to vacuum distillation at 1-3 mmHg the thus-coated paper. The DOP microcapsule coated to take out a distillate fraction of 213-28 C. to obtain paper sheet was contacted with the color-developing 291 g (yield: 81%) of methyl ester of 3,5-di(a-methyl sheet with a developed color image produced in the 15 benzyl)salicylic acid. above 2, in such a way that the coated sides of the two sheets faced each other. They were allowed to pass 90 g (0.25 mole) of the thus obtained methyl ester of through a super calender roll having a linear pressure of 3,5-di(a-methylbenzyl)salicylic acid and 28.9 g of a 100 kg/cm, whereby DOP was allowed to penetrate 40% aqueous sodium hydroxide solution (containing uniformly into the colored surface of the color-develop 20 0.275 mole of NaOH) were fed into a 500-ml flask and ing sheet. reacted at 95-105 C. for 3 hours to complete hydroly One hour after the passing, the reflectance of the sis. Then, 430 ml of water was added to dissolve the color-developing sheet was measured by X-80 Color reaction mixture. The solution was neutralized with Difference meter and expressed as Y value. The smaller sulfuric acid and filtered. The filtrate was water-washed the Y value and the smaller its difference from the Y 25 and dried to obtain 84.7 g (yield: 98%) of 3,5-di(a- value before the test, the better the plasticizer resistance methylbenzyl)salicylic acid having a purity of 99% or of the developed color image. higher. 5. Water resistance of developed color image Melting point: 147-150° C. A sample color-developing sheet, which had been subjected to color development in the same manner as 30 in the above 2, was dipped in water for 2 hours. Change Elemental analysis (%) in density of the developed color image was observed C H O visually. Calculated 79.77 6.36 13.87 (C24H24O3) 6- Yellowing property of color-developing sheet Observed 80.16 6.31 6-1 Yellowing by NO. 35 Following JISL-1055 (Testing Method for NO, Gas H-NMR (CDCl3) 1.6 (m,6H), 4.1 (m, 1H), 4.6 (m, Fastness of Dyed Materials and Dyes), a sample color 1H), 7.1-7.3 (m, 1H), 7.65 (m, 1H), 9.4 (Br, 1H), 10.5 developing sheet was stored for 1 hour in a closed ves (s, 1H). sel of an atmosphere of NO gas generated by the reac MS: m/z =346(M+). tion of NaNO2 (sodium sulfite) and H3PO4 (phosphoric The results of measurement by HLC made under the acid), to examine the degree of its yellowing. following conditions are shown in FIG. 1. One hour after completion of the storage, the reflec Chromatograph: LIQUID CHROMATOGRAPH tance of the color-developing sheet was measured by LC-3A (a product of Shimadzu) X-80 Color Difference Meter, and expressed as WB Column: YMC-Pack AM-312 value. The greater the WB value and the smaller its 45 Mobile phase: Acetonitrile/MeoH/water/trifluoroa difference from the WB value of a sheet not exposed to cetic acid=725 ml/100 ml/175 ml/0.5g NO gas (expressed as untested sheet in Table 2), the Flow rate: ml/min smaller the yellowing property in an NOx atmosphere. Detector: SPD-2A (UV-254 nm) 6-2 Yellowing by light Wave analysis: Shimadzu Chromatopack C-R3A A sample color-developing sheet was exposed to 50 light for 4 hours in a carbon arc fade meter (manufac EXAMPLE 2 tured by Suga Testing Machine Co., Ltd.). After the 69.2 g (0.2 mole) of the 3,5-di(a-methylbenzyl)salicy exposure, the reflectance of the sample color-develop lic acid obtained in Example 1 was dissolved in an aque ing sheet was measured by X-80 Color Difference ous alkali solution obtained by dissolving 8.8g of 95% Meter and expressed as WB value. The greater the WB 55 sodium hydroxide (0.21 mole as NaOH) in 500 g of value and the smaller its difference from the WB value water. The resulting aqueous solution was dropwise of an unexposed sheet (expressed as untested sheet in added, in 1 hour, to an aqueous solution obtained by Table 2), the smaller the yellowing property upon expo dissolving 31.6 g of zinc sulfate heptahydrate in 300 ml sure to light. of water, and the mixture was aged for 1 hour. Then, the mixture was filtered. The filtrate was waterwashed EXAMPLE 1 and dried to obtain 70g of zinc salt of 3,5-di(a-methyl Into a flask were fed 152.2 g (1 mole) of methyl sali benzyl)salicylic acid. cylate, 281.2 g (2 moles) of 1-chloroethylbenzene and 3 g of trifluoromethanesulfonic acid. They were sub EXAMPLE 3 jected to reaction at room temperature (20° C) for 5 65 Into a flask were fed 190.3 g (1.25 moles) of methyl days. salicylate and an acid catalyst obtained by disolving 5g After completion of the reaction, 1,500 ml of toluene of zinc chloride in 2 g of concentrated hydrochloric was fed to dissolve the reaction mixture. Then, 100 ml acid. The flask inside temperature was elevated to 35 5,326,739 11 12 C., and 404.3 g (2.87 moles) of 1-chloroethylbenzene of zinc salt of an a-methylbenzyl-substituted salicylic was dropwise added in 2 hours while the same tempera acid composition. ture was maintained. After completion of the dropwise addition, the mixture was aged at the same temperature EXAMPLE 6 for 20 hours. Then, 750 m) of toluene was added to 5 Into a flask were fed 76.1 g (0.5 mole) of methyl dissolve the mixture, after which 150 ml of water was salicylate, 1 g of antimony chloride (SbCls) and 147.6 g. added. Stirring was carried out at 60-70' C. for 0.5 ( 1.05 moles) of 1-chloroethylbenzene. They were sub hour, and then the mixture was allowed to stand until it jected to reaction at 30-35 C. for 8 hours. The reac separated into two layers, i.e. an organic layer and an tion mixture was heated to 70° C., and 200 ml of hot aqueous layer (a lower layer). The lower aqueous layer 10 water was added. The resulting mixture was heated to was removed and the organic layer was subjected to 95-98 C. Thereto was dropwise added 170 g of a 15% distillation to remove the solvent. The residue was queous sodium hydroxide solution in 2 hours. The mix found by HLC to consist of 2.9% of methyl ester of ture was aged at 98-100° C. for 5 hours to complete monosubstituted salicylic acid, 80% of methyl ester of hydrolysis. The hydrolyzate was found by HLC to 15 consist of 12% of monosubstituted salicylic acid, 68% disubstituted salicylic acid and 11.2% of methyl ester of of disubstituted salicylic acid , 18% of trisubstituted trisubstituted salicylic acid. The residue was subjected salicylic acid and 2% of others. 700 ml of water was to vacuum distillation at 1-3 mmHg to take out a distil added for dilution. The dilution product was adjusted to late fraction of 213'-218 C. to obtain 338g (yield: 75%) pH 9 with sulfuric acid. Thereto was dropwise added of methyl ester of 3,5-di(a-methylbenzyl)salicylic acid. 180 g of a 43% aqueous zinc sulfate solution at 30°C. in This product was hydrolyzed with a 40% aqueous so 1 hour. The mixture was aged for 1 hour and filtered. dium hydroxide solution in the same manner as in Ex The filtrate was water-washed and dried to obtain 200 g ample 1 to obtain 318 g (yield: 98%) of 3,5-di(a-methyl of zinc salt of an a-methylbenzyl-substituted salicylic benzyl)salicylic acid of 99% purity. acid composition. 25 EXAMPLE 4 EXAMPLE 7 Into a flask were fed 16.6 g (0.1 mole) of ethyl salicyl Into a flask were fed 76.1 g (0.5 mole) of methyl ate, 33.8 g (0.24 mole) of 1-chloroethylbenzene and 0.3 salicylate and an acid obtained by dissolving 2 g of zinc g of trifluoromethanesulfonic acid. They were sub chloride in 0.8 g of concentrated hydrochloric acid. jected to reaction at 20° C. for 30 hours. After comple 30 The flask inside temperature was elevated to 35 C. tion of the reaction, 150 ml of toluene was added to Thereto was dropwise added 161.7 g (1.15 moles) of dissolve the reaction mixutre. Then, 50 ml of water was 1-chloroethylbenzene at the same temperature in 2 added, and stirring was carried out at 60-70° C. for 0.5 hours. After completion of the dropwise addition, the hour. The mixture was allowed to stand until it sepa mixture was subjected to reaction at the same tempera rated into two layers, i.e. an organic layer and an aque 35 ture for 20 hours. The reaction mixture was heated to ous layer (a lower layer). The lower aqueous layer was 70° C., and 200 ml of hot water was added. The mixture removed, and in the same manner as in Example 1, the was heated to 95-98 C. and 170 g of a 15% aqueous organic layer was subjected to distillation to remove the sodium hydroxide solution was dropwise added in 2 solvent. The residue was found by HLC to consist of hours. The mixture was aged at 98-100° C. for 5 hours 6% of ethyl salicylate, 4.5% of ethyl ester of monosub to complete hydrolysis. The hydrolyzate was found by stituted salicylic acid, 76.8% of ethyl ester of disubsti HLC to consist of 7% of monosubstituted salicylic acid, tuted salicylic acid and 12.7% of ethyl ester of trisubsti 80% of disubstituted salicylic acid and 13% of trisubsti tuted salicylic acid. The residue was subjected to vacu tuted salicylic acid. 700 ml of water was added for uum distillation to obtain 26.2 g (yield: 70%) of ethyl dilution. The dilution product was adjusted to pH 9 ester of 3,5-di(a-methylbenzyl)salicylic acid. The ester 45 with sulfuric acid. Thereto was dropwise added 180g of was hydrolyzed with 40% sodium hydroxide to obtain a 43% aqueous zinc sulfate solution at 30° C. in 1 hour. 23.7 g (yield: 98%) of 3,5-di(a-methylbenzyl)salicylic The mixture was aged for 1 hour and filtered. The fil acid of 99% purity. trate was water-washed and dried to obtain 200 g of EXAMPLE 5 zinc salt of an a-methylbenzyl-substituted salicylic acid 50 composition. Into a flask were fed 76.1 g (0.5 mole) of methyl salicylate, 1.5 g of stannic chloride (SnCl2) and 54.6g EXAMPLE 8 (1.1 moles) of 1-chloroethylbenzene. They were sub Into a flask were fed 76.1 g (0.5 mole) of methyl jected to reaction at 20-25 C. for 5 hours. Then, the salicylate, 1.5 g of trifluoromethanesulfonic acid and reaction mixture was heated to 70° C., and 200 ml of 55 154.6 g (1.1 moles) of 1-chloroethylbenzene. They were water was added. The resulting mixture was heated to subjected to reaction at 20-25 C. for 5 days. The reac 95-98 C. and 170 g of 15% sodium hydroxide was tion mixture was heated to 70° C. and 200 ml of hot dropwise added in 2 hours. The mixture was aged at water was added. The mixture was heated to 95-98 C. 98-100° C. for 5 hours to complete hydrolysis. The Thereto was dropwise added 170 g of a 15% aqueous hydrolyzate was found by HLC to consist of 2% of 60 sodium hydroxide solution in 2 hours. The mixture was salicylic acid, 13% of monosubstituted salicylic acid, aged at 98-100° C. for 5 hours to complete hydrolysis. 67% of disubstituted salicylic acid, 17% of trisubstitu The hydrolyzate was found by HLC to consist of 88% ted salicylic acid and 1% of others. 700 ml of water was of disubstituted salicylic acid, 11% of trisubstituted added for dilution. The dilution product was adjusted to salicylic acid and 1% of others (FIG. 2). In FIG. 2, RT pH 9 with sulfuric acid. Thereto was dropwise added 65 8,427 indicates 3,5-di(a-methylbenzyl)salicylic acid, 700 180g of a 43% aqueous zinc sulfate solution, at 30° C. in ml of water was added for dilution. The dilution prod 1 hour. The mixture was aged for 1 hour and filtered. uct was adjusted to pH 9 with sulfuric acid. Thereto The filtrate was water-washed and dried to obtain 200 g was dropwise added 180g of a 43% aqueous zinc sulfate 5,326,739 13 14 solution at 30° C. in 1 hour. The mixture was aged for 1 with an a-methylbenzyl halide represented by the for hour and filtered. The filtrate was water-washed and mula (II) dried to obtain 200 g of zinc salt of 3,5-di(a-methylben zyl)salicylic acid. CH3 (II) COMPARATIVE EXAMPLE 1. 5 th-x. Into a flask were fed 76.1 g (0.5 mole) of methyl salicylate and 10 g of methanesulfonic acid. While the flask inside temperature was maintained at 60-65 C., 140 g (1.346 moles) of styrene was dropwise added in 14 10 hours. After completion of the dropwise addition, the R2 R3 mixture was aged at the same temperature for 30 min utes. The reaction mixture was subjected to hydrolysis where R2 and R3 each represent a hydrogen atom or an with a 40% aqueous sodium hydroxide sdilution in the alkyl group of 1-4 carbon atoms and X represents a same manner as in Example 1. Then, neutralization with 15 halogen atom, in the presence of an acid catalyst and sulfuric acid was carried out to obtain an oily product hydrolyzing the resulting 3,5-di(a-methylbenzyl)salicy containing 3,5-di(a-methylbenzyl)salicylic acid. lic acid ester. The oily product was found by HLC to contain 2. The color-developing sheet of claim 1 wherein the 43.3% of 3,5-di(a-methylbenzyl)salicylic acid. The re a-methylbenzyl-substituted salicylic acid derivative sults of HLC are shown in FIG. 3. In FIG. 3, RT 8,437 20 composition comprises 0-40% by weight of an a-meth indicates 3,5-di(a-methylbenzyl)salicylic acid. ylbenzyl-monosubstituted salicylic acid derivative, It was tried to convert the oily product to a zinc 0-40% by weight of an a-methylbenzyl-trisubstituted derivative as in Example 8. However, a gummy or salicylic acid derivative and 60-90% by weight of a block-like substance was formed, making difficult filtra 3,5-di(a-methylbenzyl) salicylic acid derivative and tion, water washing and drying. wherein the three salicylic acid derivatives occupy 95% TABLE 1 Color Developability and Developed Color Properties of Color-Developing Sheets Blue color development (20' C, 65% RH.) Low-temp. color development Light fastness Plasticizer Water (5' C, 60% RH.) Developed color density of of developed resistance of resistance of Developed color density of color-developing sheet (Y) color image (Y) developed color developed color-developing sheet (Y) Example 1.5 minutes later 24 hours later 2 hours 4 hours image (Y) color image 1.5 minutes later 24 hours later 2 59.9 56.1 650 74.1 60.6 Disappeared 69.9 58.5 5 56.9 54.9 64.5 740 57.9 Good 62.3 56.9 6 56.9 54.5 64.5 740 57.8 Good 62.5 56.5 7 57.2 55.9 64.8 73.8 58.4 Good 63.0 57.9 8 58.4 55.9 64.9 74.1 59.0 Nearly good 65.2 57.9

TABLE 2 Yellowing of Color-Developing Sheets 40 Untested Tested sheet sheet Yellowing by NOx Yellowing by light Example (WB value) (WB value) (WB value) 2 84.5 81.4 (3.1) 77.1 (7.4) 65 84.5 81.2 (3.3) 76.8 3.(7.7) 45 by weight or more of the composition. 7 84.3 81.6 (2.7) 76.8 (7.5) 3. The color-developing sheet of claim 1, wherein R1 8 84.3 8.5 (2.8) 76.9 (7,4) in the salicylic acid ester is methyl Each figure in parentheses indicates a difference of the WB value of untested sheet 4. The color-developing sheet of claim 1, wherein R2 and the WB value of tested sheet. and R3 in the a-methylbenzyl halide are hydrogen 50 atoms and X is a chlorine atom. What is claimed is: 5. The color-developing sheet of claim 1, wherein R1 1. A color-developing sheet comprising a substrate in the salicylic acid ester is methyl, R2 and R3 in the and, as a color developer, a polyvalent-metal-modified a-methylbenzyl halide are hydrogen atoms and X is a reaction product of a polyvalent metal salt and an a chlorine atom. methylbenzyl-substituted salicylic acid derivative com- 55 6. The color-developing sheet of claim 5, wherein the position comprising 60-90% by weight of a 3,5-di(a- polyvalent metal of the polyvalent metal salt is zinc. methylbenzyl)salicylic acid derivative, which is pro 7. The color-developing sheet of claim 1, wherein the duced by reacting a salicylic acid ester represented by polyvalent metal of the polyvalent metal salt is calcium, the formula (I) magnesium, aluminum, copper, zinc, tin, barium, cobalt 60 or nickel. OH (I) 8. The color-developing sheet of claim 1, wherein the COOR, polyvalent metal of the polyvalent metal salt is zinc. 9. A color-developing sheet comprising a substrate and, as a color developer, a polyvalent-metal-modified 65 reaction product of a polyvalent metal salt and a 3,5- di(a-methylbenzyl)salicylic acid compound which is where R represents an alkyl group, an aralkyl group or produced by reacting a salicylic acid ester represented a cycloalkyl group each having 1 to 12 carbon atoms, by the formula (I) 5,326,739 15 16 halogen atom, in the presence of an acid catalyst, sepa OH (I) rating a resulting 3,5-di(a-methylbenzyl)salicylic acid ester from the reaction mixture by vacuum distillation and hydrolyzing the 3,5-di(a-methylbenzyl) salicylic acid ester. Ór" 10. The color-developing sheet of claim 9, wherein R1 in the salicylic acid ester is methyl. where R represents an alkyl group, an aralkyl group, or 11. The color-developing sheet of claim 9, wherein a cycloalkyl group each having 1 and 12 carbon atoms, R2 and R3 in the a-methylbenzyl halide are hydrogen with an a-methylbenzyl halide represented by the for- O atons and X is a chlorine atoms. mula (II) 12. The color-developing sheet of claim 9, wherein R1 in the salicylic acid ester is methyl, R2 and R3 in the CH3 (II) a-methylbenzyl halide are hydrogen atoms and X is a chlorine atom. CH-X, 15 13. The color-developing sheet of claim 12, wherein the polyvalent metal of the polyvalent metal salt is zinc. 14. The color-developing sheet of claim 9, wherein the polyvalent metal of the polyvalent metal salt is 20 calcium, magnesium, aluminum, copper, zinc, tin, bar ium, cobalt or nickel. 15. The color-developing sheet of claim 9, wherein where R2 and R3 each represent a hydrogen atom or an the polyvalent metal of the polyvalent metal salt is zinc. alkyl group of 1-4 carbon atoms and X represents a se 25

30

35

45

50

55

65