Abstract: Disclosed is a photodiscoloration-resistant polyester resin composition comprising 100 parts by weight of a polyester resin and, incorporated therein, (1) 3 to 50 parts by weight of a brominated cyanuric acid ester compound; and (2) a benzotriazole-type ultraviolet stabilizer in an amount of up to 5 parts by weight per 100 parts by weight of the polyester resin. This composition is excellent in the flame retardance and photodiscoloration resistance, and bleeding of the contained flame retardant does not occur in this composition.

Abstract: Isocyanurate esters of thioalkanoamidophenols useful in the stabilization of organic materials normally susceptible to oxidative degradation are prepared by reacting an appropriate isocyanurate trithiol, which is a selected tris-mercapto alkanoic acid ester of tris-(2-hydroxyethyl) isocyanurate with an appropriate alkenyl compound, which is a selected N-alkenoyl[4-amino-(mono- or dialkyl)phenol] or, where the alkano moiety is a sole methylene group, by reaction of tris-(2-hydroxyethyl) isocyanurate with an appropriate [mercapto-N-(mono- or di-alkyl-4-hydroxyphenylalkanamide alkenoic] acid. In a preferred embodiment, the ester is 1,3,5-tris{2-hydroxy ethyl-[3-mercapto-(3',5'-di tert-butyl-4'-hydroxypropionanilide)]propionate}isocyanurate.

Abstract: Hot melt adhesives with long open time and good cold metal bonding are made of blends of an at least partially crystalline copolymer of butene-1 and ethylene, an aliphatic, substantially non-polar resin, an antioxidizing agent and, optionally, microcrystalline wax.

Abstract: The propylene-ethylene block copolymer composition of the invention is excellent in transparency as well as in stiffness and low temperature impact strength.The copolymer composition of the present invention comprises (a) from 0.01 to 1.0 part by weight of a nucleating agent and (b) from 0.01 to 3.0 parts by weight of talc having an average particle size of not more than 10 microns, admixed in 100 parts by weight of propylene-ethylene block copolymer. Said propylene-ethylene block copolymer was formed in a multi-stage polymerization process wherein the ethylene content of the copolymer formed at the propylene-ethylene copolymerization stage is from 5 to 40% by weight based on the total polymerization amount of the copolymer formed at said propylene-ethylene copolymerization stage.

Abstract: Hot melt adhesives with long open time good bonding to cold metals are made of blends of a maleic anhydride modified copolymer of butene-1 and ethylene, an aliphatic, substantially non-polar resin, a antioxidizing agent and, optionally, microcrystalline wax, a block copolymer and atactic polypropylene.

Abstract: The heat stability of arylene sulfide resins, such as poly(p-phenylene sulfide) resin, is improved by the addition of cure retarders comprising phenolic amide or ester-based antioxidants. The resin compositions of the invention are particularly applicable for reducing gel formation during melt extrusion.

Abstract: Polyvinyl butyral with a degree of acetalization of at least 75% is added to a dental cement on basis of calcium hydroxide and salicyclic esters of aliphatic alcohols. By this additive improved water resistance and increased compressive strength upon hardening are imparted to the dental cement. The obtained dental cement furthermore has strongly alkaline pH value, so that an effective protection of the pulp can be achieved and formation of a secondary dentin layer is stimulated. In the common formulation of the materials for the dental cement in form of two separate mixing components the polyvinyl butyral can be added either to the mixing component containing the salicylic acid ester or to the mixing component containing the calcium hydroxide, or also to both components.

Abstract: The high temperature aging of polyamides is substantially improved by incorporating therein an antioxidant and an oxide of a metal of Group II or III of the Periodic Table, preferably a crystalline aluminosilicate such as a synthetic zeolite. The amount of antioxidant is preferably 1 to 5% and the amount of metal oxide is preferably 0.5 to 5%. Polyamides which can be stabilized in this way include Nylon-6, Nylon-11 and Nylon-12.

Abstract: Improved injection moldability of polyethylene terephthalates is achieved by the addition of an epoxidized plasticizer and a nucleating agent cooperative with the epoxidized plasticizer to achieve the improved moldability even when the composition is injection molded using mold temperatures of at least as low as 93.degree. C.

Abstract: About equimolar ethylene/chlorotrifluoroethylene copolymer compositions are stabilized against thermal degradation by incorporating therein a stabilizing system comprising (a) a phosphite of an organic plyhydric phenol; (b) a salt of a carboxylic acid and a metal of Group II of the Periodic Table; and (c) an ester of a (4-hydroxy-5-alkylphenyl)alkanoic acid.

Abstract: A refractory composition or mixture utilizing basic aggregates is disclosed which does not discolor when a phenolic binder is used, and provides improved flexural strength. The composition contains specific proportions of phenolic resin and a compound having a pKa of less than 9.5 at 25.degree. C. and basic aggregates.

Abstract: Heat-sterilizable films are made from a polymer blend of about 10 to about 60 wt % random propylene-ethylene copolymer containing from about 1 to about 6 wt % ethylene-derived units and about 40 to about 90 wt % linear low density polyethylene. The films are especially useful in the manufacture of collapsible parenteral solution bags and overwraps.

Abstract: A resin composition comprising a poly-1-butene polymer and at least one hindered phenol selected from the group consisting of (a) 3,5-di-tert-butyl-4-hydroxybenzoates of the following formula ##STR1## wherein R represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms, (b) 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, (c) 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, (d) tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, (e) n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, (f) a nickel salt of a monoethyl ester of bis(3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid), (g) 2,2'-dihydroxy-3,3'-di(.alpha.

Abstract: Oligomers of 2,2,6,6-tetramethylpiperidinol polycarboxylic acid esters are provided having the formula: ##STR1## wherein: Z is the residue of an aliphatic or aromatic or nitriloaliphatic or hydroxy aliphatic polycarboxylic acid having from three to six carboxylic acid groups and from one to thirty carbon atoms; ##STR2## wherein R.sub.3 is hydrogen, alkyl and hydroxyalkyl having from one to about twenty carbon atoms; cycloalkyl having from six to about twenty carbon atoms; aryl having from six to about twenty carbon atoms; or cycloalkylene with the N in the ring and having from two to five carbon atoms;R is alkylene having from two to about twelve carbon atoms; cycloalkylene having from three to about twelve carbon atoms; phenylene having from six to about twenty carbon atoms; mixed alkylenecycloalkylene or alkylene phenylene or oxyalkylene having from two to about twelve carbon atoms; ##STR3## wherein R.sub.4 is alkyl having from one to about six carbon atoms;R.sub.

Abstract: Disclosed are stabilized polyester compositions having significantly improved weatherability, said polyesters consisting of homopolyesters derived from a dicarboxylic acid component wherein at least a major portion of which is 1,4-cyclohexanedicarboxylic acid (or ester) having a trans isomer content of at least 65% and a glycol component wherein at least a major portion of which is 2,2,4,4-tetramethyl-1,3-cyclobutanediol and copolyesters thereof with modifying aliphatic glycols and/or aliphatic dicarboxylic acids, said polyesters being stabilized with the combination of at least one ultraviolet light stabilizing compound compatible with said polyester and at least one hindered amine light stabilizer having the formulae ##STR1## the groups shown as R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently selected from various substituents.

Abstract: A stabilizer for polymeric substances made up of a sulfur-containing compound of the formula: ##STR1## wherein R.sub.1 represents an alkyl group having 4 to 20 carbon atoms and a phenolic compound of the general formula: ##STR2## wherein R.sub.2 represents an alkyl group having 1 to 4 carbon atoms, in the ratio (I):(II) of 1:0.1-2 by weight.The combination of the above stabilizer with a polymeric substance, such as synthetic rubber is also contemplated herein.

Abstract: Disclosed are stabilized polyester compositions having significantly improved weatherability. These polyesters consist of copolyesterethers derived from a dicarboxylic acid component comprising about 80-100 mole % 1,4-cyclohexanedicarboxylic acid having a trans isomer content of at least 70% and about 0-20 mole % of a second dicarboxylic acid and a glycol component comprising about 70-95 mole % 1,4-cyclohexanedimethanol and about 5-30 mole % of a polyalkylene ether glycol having a molecular weight of about 600 to about 3000. The copolyesterether compositions further comprise a stabilizing effective amount of the combination of (1) at least one hindered phenolic antioxidant, (2) at least one ultraviolet light stabilizing compound compatible with said copolyesterether and (3) at least one hindered amine light stabilizing compound having the formulae ##STR1## the groups shown as R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently selected from various substituents.

Abstract: Cyanoacrylate adhesive compositions containing a tannin, e.g., digallic acid, tannic acid, or other hydrolyzable or condensed tannin. The inclusion of tannin increases adhesion and heat resistance of the cured adhesive on metal substrates.

Abstract: A method for treating polymers of ethylene which have been stabilized with hindered phenolic stabilizer to reduce the discoloration produced upon processing the stabilized polymer at elevated temperature wherein before completion of the processing at elevated temperature there is admixed with the stabilized polymer compositions at least one compound chosen from the group consisting of aliphatic hydroxy compounds and epoxy-containing compounds. In a preferred embodiment, the polymer of ethylene and aliphatic hydroxy compound are further admixed with water. In another embodiment of the invention the aliphatic hydroxy compounds contain from 1 to 4 hydroxyl groups and are water soluble.A treated polymer of ethylene stabilized with hindered phenolic stabilizer that has been admixed with a compound chosen from the group consisting of aliphatic hydroxy compounds and epoxy-containing compounds.

Abstract: The antioxidative degradation process, and/or color stability of carboxyl-containing ethylene interpolymers is improved by incorporating therein at least one aromatic bis(organophosphorus) compound, with or without a hindered phenol antioxidant and/or a dicarboxylic acid.

Abstract: A process for the preparation of high molecular weight polyphenylene ethers from alkyl-substituted monohydric phenols by an oxidative coupling reaction with oxygen in the presence of a catalyst complex of a copper salt and an organic amine, subsequent stopping of the reaction and removal of the metal component of the catalyst by addition of chelating and/or salt-forming agents, wherein the polymer solution is treated with a compound having the general structure: ##STR1## where R.sup.2 and R.sup.3 can be identical or different and each is OH, NH.sub.2, NHR.sup.5, where R.sup.5 is alkyl or cycloalkyl, or SH, and where R.sup.1 and R.sup.4 are identical or different, being hydrogen, alkyl, cycloalkyl, aryl, carbonyl, carboxyl, carboxyalkyl or nitrile, and can be linked to form a ring, advantageously in an amount of from 0.1 to 100 mmoles and advantageously in from 1 to 20% strength aqueous solutions.

Abstract: A polyolefin resin composition for metallized films, having superior high-impact properties and heat-sealability and also superior printability and adhesive properties of metallized surface and further a good taken-up figure of rolled film is provided, which composition is obtained by blending a crystalline propylene-.alpha.-olefin copolymer containing 70% by weight or more of propylene component and having a crystalline m.p. of 150.degree. C. or lower, with a high density polyethylene having a density of 0.940 g/cm.sup.3 or higher, in blending ratios of 96 to 80% by weight of the copolymer and 4 to 20% by weight of the polyethylene, the ratio of the melt flow rate of the polyethylene to that of the copolymer being .gtoreq.0.7.

Abstract: Dental cements with syringate esters such as 2-ethylhexyl syringate with or without vanillate esters dissolved in o-ethoxybenzoic acid as ingredients of the liquid when mixed with metal oxide powder yield rapid setting, insoluble cements that have high strength, do not inhibit free radical polymerization, adhere strongly to metal, and reduce carries. Use of silanized glass filler to the powder in conjunction with the addition of monomer to the liquid gives an even stronger cement.

Abstract: Improved injection moldability of polyethylene terephthalates is achieved by the addition of an epoxidized plasticizer and a nucleating agent cooperative with the epoxidized plasticizer to achieve the improved moldability even when the composition is injection molded using mold temperatures of at least as low as 93.degree. C.

Abstract: Under thermal aging conditions of reinforced polymeric materials, some reinforcements are not as effective as others in providing longevity for the fiber reinforced polymeric materials. A method is provided for incorporating an additional amount of antioxidant into the polymeric materials before the reinforcement is added to the polymeric materials or into an aqueous treating solution for the fibrous reinforcement. The antioxidant is of low volatility and good thermal resistance, and when added to the polymer directly is used in an amount greater than three parts per hundred parts of the polymer (PHR). When the antioxidant is added to the aqueous treating solution for treating the fibrous reinforcements, the antioxidant is in the form of an oil-in-water emulsion.

Abstract: A connector member (11) is disclosed for sealed connection with a second connector member (30), to permit sealed flow of material through the joined connector members. The connector member (11) is made of a material selected from the group consisting of aliphatic hydrocarbon resins, aliphatic polyester resins, copolymers of olefins and vinyl acetate, and olefin-acrylate copolymers. The material also contains an effective amount of an antioxidant agent being selected to provide to the material the characteristic of permitting transmission of at least 15 percent of at least one wavelength of ultraviolet radiation having a wavelength between 220 and 300 nanometers through a thickness of 0.003 inch of the material.

Abstract: Thin walled thermoformed articles of partially crystallized polyethylene terephthalate containing a minor component of a polyolefin which exhibit improved impact resistance and high temperature dimensional stability. Method for thermoforming such articles using polyethylene terephthalate/polyolefin blends which give improved mold release.

Abstract: The blocking characteristics of ethylene interpolymers containing --COOH groups are reduced by treating such polymers with a solution of an inorganic compound of a Group I-A metal such as trisodium phosphate and an organic compound of a Group I-A metal such as sodium acetate or a combination thereof.

Abstract: UV curable coating compositions are provided based on the use of photoinitiator with the hydrolysis product of silylacrylate and aqueous colloidal silica. The UV curable silicone coating compositions also can contain polyfunctional acrylate. The UV curable hardcoat composition can be applied onto various substrates, for example, a polycarbonate substrate, and thereafter cured under UV radiation to produce adherent and abrasion resistant coated articles.

Abstract: Ester-carbonate interchange in blends of aromatic polycarbonates and poly(alkylene dicarboxylates) is inhibited by adding thereto a hydroxy- or amino-substituted carboxylic acid derivative such as methyl salicylate, malic acid, glycine or dibutyl tartrate.

Abstract: An improved molding composition is provided which exhibits desirable weathering resistance and UV stability comprising an oxymethylene copolymer having at least one chain containing from about 85 to 99.6 mole percent of oxymethylene units interspersed with about 0.4 to 15 mole percent of oxyethylene units, about 0.1 to 1 percent by weight of 1,6-hexamethylene bis-(3,5-di-tert-butyl)-4 hydroxy hydrocinnamate, about 0.015 to 0.4 percent by weight of 2,4,6-triamino-symtriazine, about 0.1 to 0.75 percent by weight of bis(1,2,2,6,6-pentamethyl-4-piperidinyl) ((3,5-bis(1,1-dimethylethyl-4-hydroxyphenol)methyl)) butyl propanedioate and about 0.25 to 1.0 percent by weight of 2-hydroxy-4-n-octoxy-benzophenone.

Abstract: Polyoxyalkylene polyether polyols are stabilized against oxidative degradation by incorporating therein a synergistic stabilizing composition containing (1) a mixture of butylated phenols consisting of 2-tertiary butyl phenol, 3,5-ditertiary butyl-4-hydroxyhydrocinnamate and 1,6-hexamethylene bis(3,5-ditertiary-butyl-4-hydroxyhydrocinnamate) or tetrakis [methylene(3,5-ditertiary butyl-4-hydroxyhydrocinnamate)] methane (2) a p,p'-dialkyldiphenylamine such as p,p'-dioctyldiphenylamine and (3) a phenothiazine compound. Polyurethane foams are stabilized against scorching when the stabilized polyols are utilized in the foam preparation or the stabilizing composition is added with other reactants.

Abstract: The heat stability of arylene sulfide resins, such as poly(p-phenylene sulfide) resin, is improved by the addition of cure retarders comprising phenolic amide or ester-based antioxidants. The resin compositions of the invention are particularly applicable for reducing gel formation during melt extrusion.

Abstract: It has been found that the addition of small amounts of a benzoate or acetate ester of a polyfunctional hydroxy-containing compound to a maleic anhydride-containing resin greatly increases the flowability and processibility of these resins.

Abstract: This invention relates to a powdered phenolic resin composition suitable for the production of dry processed resinbonded felt. The phenolic resin composition imparts a good release of the felt from the heated platen or belt and has a rapid cure rate. The powdered phenolic composition is composed of a novolac type phenolic resin, or a mixture of novolac and resole type with an aromatic carboxylic acid as an additive. The resin mixture has a bulk density of 0.29-0.36 gm/cm.sup.3, and contains 0.3-5 parts by weight of the aromatic carboxylic acid to 100 parts by weight of phenolic resin. Said aromatic carboxylic acid has the formulaR--Ar--COOHwhereinR is selected from hydrogen, hydroxy or alkoxy groups, andAr is selected from phenyl, phenylalkenyl or phenylalkyl groups.

Abstract: Disclosed are improved styrene-butadiene (SBR) core-alkyl acrylate/methacrylate shell-polymer compositions and an improved process for applying patterns to textiles by screen printing employing these polymer compositions as binders. The process for preparing the improved polymers is also set forth. The core comprises an SBR copolymer which contains an antioxidant and is at least partially encased by an integral shell of a copolymer of an alkyl acrylate or methacrylate which is formed by copolymerization with an ultraviolet light stabilizer. When used as binders for screen printing, these compositions produce textiles which exhibit a desirable combination of crock fastness, cyclic aging and hand properties.

Abstract: Described is a genus of compounds defined according to the structure: ##STR1## wherein Z represents carbinol having the structure: ##STR2## or carboxaldehyde having the structure: ##STR3## and wherein R represents 3-heptanyl or phenyl produced by (i) reacting a carboxylic acid with 2,2-dimethyl-1,3-propanediol to form the compound wherein Z represents carbinol; (ii) and then, if, desired, subsequently reacting the resulting alcohol to form an aldehyde; and organoleptic uses of such compounds in the field of perfumery, colognes and perfumed articles (e.g. perfumed polymers, or solid or liquid anionic, cationic, nonionic or zwitterionic detergents, fabric softener compositions, drier-added fabric softener articles, hair preparations, hair sprays, bath preparations and the like).

Abstract: This disclosure relates to the use of certain heat-treated carbon blacks as stabilizers against the effects of degradation caused by visible and ultraviolet light in the preparation of polypropylene resin compositions containing conventional antioxidants which impart thermal stability to the polypropylene resin.

Abstract: Polyacetal molding materials which contain, as a stabilizer, from 0.1 to 10% by weight of a melamine resin, the latter being a melamine-formaldehyde condensate, having a mean degree of polymerization of from 1.2 to 6.0 and a melamine:formaldehyde ratio of from 1:2 to 1:5.5, which has been partially etherified with a C.sub.1 -C.sub.4 -alkanol so that the ratio melamine:ether radicals is from 1:1.5 to 1:5.0 and the ratio melamine:free methylol groups is from 1:0.5 to 1:3. The molding materials can be converted to moldings which can be used industrially at elevated ambient temperatures.

Abstract: Synthetic resins, particularly polyolefins, are markedly improved in their resistances to heat and oxidation by the incorporation of a 2-methyl-4-t-butyl-5-hydroxyphenylalkanoic acid ester alone or in combination with a thioether-type antioxidant represented by the general formula ##STR1## wherein R represents an alkyl group of 12 to 20 carbon atoms, or by the general formula ##STR2## wherein R represents an alkyl group of 4 to 20 carbon atoms.

Abstract: Disclosed is a flame retardant polyamide composition having desirable mechanical, electrical and processing properties, and therefore, being useful for producing parts of electric and electronic devices and appliances. The composition comprises a polyamide resin matrix and 1 to 40%, based on the weight of the polyamide matrix, of a flame-retarding agent in the form of fine particles dispersed in the matrix. The composition is characterized in that the flame-retarding agent consists of at least one member selected from:(A) crystals of addition salts of cyanuric acid or isocyanuric acid with melamine, and;(B) mixed crystals of addition salts of cyanuric acid or isocyanuric acid with a mixture of melamine and acetoguanamine in an amount by mole not larger than that of the melamine.

Abstract: 1,3-Dicarbonyl compounds are provided having the formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are defined in the description as well as metal and organotin enolate salts thereof.The compounds are effective in enhancing the resistance to deterioration by heat and light of polyvinyl halide resins.

Abstract: Filled thermoplastic compositions useful as sound deadening sheeting having improved tensile elongation are obtained by blending about 5-60 percent by weight of a mixture of at least two copolymers of ethylene, having specified polar comonomer contents, about 40-90 percent by weight of filler, 0-15 percent by weight of plasticizer selected from the group consisting of processing oils, polyesters, polyethers and polyether esters, and optionally modifying resins such as elastomeric polymers and certain other ethylene and propylene homo- and copolymers.

Abstract: 2,2,6,6-Tetraalkyl-4-piperidyl-bis-spiro-ethers are provided, useful as stabilizers for lessening deterioration due to exposure to light of organic polymeric materials, and having the general formula: ##STR1##

Abstract: 2,6-Di-tertiary butyl phenyl pentaerythritol spiro bisphosphites are provided having the structure: ##STR1## wherein: R is alkyl having from one to six carbon atoms;R.sub.1 is methyl or ethyl;R.sub.2 is selected from the group consisting of alkyl having from one up to about eighteen carbon atoms; cycloalkyl having from three up to about twelve carbon atoms; and alkaryl and aryl having from six to about thirty carbon atoms; such groups substituted with from one to about four oxy ether--O-- and/or carboxylic ester--COO--groups; the residue of a polyhydric alcohol having from two to about eighteen carbon atoms, and from two to about ten hydroxyl groups; and the residue of a polyphenol having from six to about eighteen carbon atoms and from two to about ten phenolic hydroxyl groups.

Abstract: Compounds of the formula: ##STR1## wherein R, R' and R.sup.2 are alkyl radicals having 1 to 20 carbon atoms, phenyl radicals which may be substituted by 1 or 2 alkyl groups having 1 to 8 carbon atoms, aralkyl radicals having 7 to 12 carbon atoms, or cycloalkyl radicals having 5 to 12 carbon atoms; and wherein R.sup.3 is hydrogen or an alkyl radical having from 1 to 4 carbon atoms. These compounds have utility as synergistic stabilizers with phenolic type antioxidants for the stabilization of organic materials such as natural and synthetic polymers, rubbers, lubricants and oils, etc.

Abstract: A resin composition suitable for injection moulding and having excellent heat resistance, impact resistance and crack resistance, which is composed of polyphenylene ether and rubber-reinforced styrene resin and an amount of volatile matters in the resin having molecular weight of about 300 or less is 5000 ppm or less. This resin composition is prepared by melting and kneading the two resins above in an extruder with a vent under keeping the vent part under reduced pressure.

Abstract: Organic polymers selected from the group consisting ofpolyolefinsunsaturated elastomerscopolymers of monoolefines and diolefines with other vinyl monomerspolystyrene and copolymers thereofpolymers which are derived from .alpha.,.beta.-unsaturated acids and derivatives thereof and copolymers of these monomers with other unsaturated monomerspolymers derived from unsaturated alcohols and amines or derivatives thereofpolyacetalspolyamides and copolyamidesare stabilized against thermooxidative deterioration by the addition of acylated hydroxy acid type compounds of the formula (I) ##STR1## Wherein the meanings of the substituents and symbols in formula (I) are as defined herein.

Abstract: A flame retardant polycarbonate resin composition comprising a polycarbonate resin, a nuclear substituted benzoic acid containing at least one substituent selected from the group consisting of thiosalicylic acid and dihydroxy benzoic acid, and tetrabromobisphenol A or ##STR1## .

Abstract: A monoester compound of a 2,2'-alkylidene bis(4,6-di-substituted phenol) useful as an antioxidant in synthetic polymers having good resistant to oxides of nitrogen fumes, represented by the formula (I), ##STR1## wherein R.sub.1 and R.sub.2, which may be the same or different, each represents a C.sub.1-4 alkyl group, a C.sub.5-6 cycloalkyl group or a methyl-substituted C.sub.5-6 cycloalkyl group; and one of R.sub.3 and R.sub.4 represents a hydrogen atom and the other represents a hydrogen atom or a C.sub.1-10 alkyl group or both of them represent a methyl group; R.sub.5 represents a C.sub.4-9 alkyl group, a C.sub.3-7 cycloalkyl group, a C.sub.2-4 alkenyl group, a phenyl group, a C.sub.1-4 alkyl-substituted phenyl group, a C.sub.1-4 alkoxy-substituted phenyl group, a mono- or di- C.sub.1-4 alkyl-substituted hydroxyphenyl group, a styryl group, a benzyl group or a pyridyl group, and a method of preparing such a monoester compound.