Abstract: Hindered phenol stabilized, stereoregular polymers of branched, higher alpha-olefins can be modified with unsaturated silanes, carboxylic acids, and/or carboxylic acid anhydrides in the presence of a free radical generator in the polymer melt. These polymers can also contain additional additives, such as glass fibers. An aliphatic thio compound is added after the grafting procedure for maximum beneficial effect.

Abstract: A polymer composition comprising resin components comprising (a) 5-95 weight % of a polyamide resin, and (b) 5-95 weight % of polyolefin + unsaturated carboxylic acid-modified polyolefin, and (c) additives comprising the following compounds in amounts per 100 parts by weight of the total composition: (1) 0.1-2 parts by weight of a substituted hydrazine: (2) 0.05-2 parts by weight of a hindered phenol compound; (3) 0.05-0.5 parts by weight of a phosphite or phosphonite; and (4) 0.15-1 parts by weight of a thiodipropionate.

Abstract: A polypropylene resin containing an .alpha.-olefinic copolymer rubber and an inorganic filler is stabilized by incorporating therein the following 6 components:(A) a hindered phenolic compound having a molecular weight of not less than 500,(B) a high-molecular hindered piperidine compound such as poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6- tetramethyl-4-piperidyl)-imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperid yl)imino}],(C) a low-molecular hindered piperidine compound such as 2-methyl-2-(2,2,6,6-tetramethyl-4-piperidyl)amino-N-(2,2,6,6-tetramethyl-4 -piperidyl)propionamide,(D) a benzoate compound such as 2,4-di-t-butylphenyl 3,5-di-t-butyl-4-hydroxybenzoate,(E) a phosphorous compound such as bis(2,4-di-t-butylphenyl) pentaerythritol diphosphite, and(F) an amide compound such as ethylene-bisstearylamide. This composition may also contain a sulfur compound such as dialkyl thiodipropionate and pentaerythritol tetrakis(3-alkylthiopropionate).

Abstract: The present invention provides a resin composition which is excellent in balance of mechanical properties and processability, solvent resistance and chemical resistance. This composition comprises:(a) a polyphenylene ether resin,(b) a thermoplastic polyester resin, and(c) a compound represented by the formula:(HO)mR.sup.1 (COOR.sup.2)nwherein R.sup.1 represents a straight or branched chain saturated aliphatic hydrocarbon group of 2-20 carbon atoms, R.sup.2 represents a hydrogen atom or an alkyl or aryl group of 1-20 carbon atoms and R.sup.1 and R.sup.2 may be identical or different and m and n each represents an integer of 1 or more or a derivative thereof.This composition may further contain a rubber-like polymer.

Abstract: Polyvinyl halide-EVOH polymer compositions exhibiting a reduced tendency to stick to metal surfaces, and in particular, to chrome surfaces are described which comprise(A) at least one vinyl halide polymer;(B) from 1 to about 40% based on the weight of the vinyl halide polymer, of at least one ethylene-vinyl alcohol copolymer; and(C) from about 0.01 to about 5 phr of at least one phenolic antioxidant of the formula ##STR1## wherein R.sub.1 is hydrogen, or a hydroxyl or an alkyl group; R.sub.2 is an alkyl, alkoxy or a carboxylic ester group; and R.sub.3 is a hydroxy or an alkyl group.An improved process for melt blending mixtures comprising vinyl halide polymers and ethylene-vinyl alcohol copolymers on metal-surfaced compounding equipment is described which comprises adding to the mixture prior to melt blending, from about 0.01 to about 5 phr of the phenolic antioxidant described above.

Abstract: Melt-stable polyacetal molding compositions include a polyacetal base resin, and a carbon black-impregnated ethylenic carrier polymer in amounts to yield between about 0.1 to 30 parts by weight of carbon black. The ethylenic carrier polymer is preferably present in an amount between 0.3 to 8 times by weight of the carbon black impregnated therewithin. The compositions of this invention further contain a co-stabilization package which includes a first stabilizer selected from nitrogen-containing compounds, fatty acid ester compounds, and metal-containing compounds which contain a hydroxide, an inorganic acid salt or a carboxylic acid salt of an alkali metal or an alkaline earth metal, and a second stabilizer which is a hindered phenolic compound. Preferably, the first and second stabilizers are each used in amounts between 0.01 to 5 parts by weight, based on 100 parts by weight of the polyacetal base resin.

Abstract: A weather-resistant polyacetal resin composition which comprises(A) 100 part by weight of a polyacetal resin,(B) 0.01 to 5 parts by weight of a weathering (light) stabilizer and(C) 0.5 to 60 parts by weight of a graft copolymer comprising (a) an olefin (co)polymer and (b) one or more vinyl (co)polymers which are chemically bonded to each other to form a branched or crosslinked structure.The surface of a molded article made from the composition is excellent in weathering resistance, so that it undergoes less crack and reduced discoloration.

Abstract: An improved aqueous electrocoating composition having a binder of an epoxy-amine adduct and a blocked polyisocyanate crosslinking agent; wherein the improvement is the use of an antioxidant additive which is a combination of a phenolic antioxidant and a sulfur-containing antioxidant. The additive reduces overbake yellowing of the composition and the intercoat delamination of the composition and the topcoat upon exterior exposure.

Abstract: Thermoplastic polymer blends comprising a major proportion by weight of certain monovinylidene aromatic copolymers and a minor proportion by weight of an acetal polymer have good processability and a beneficial combination of physical and chemical properties including thermal/dimensional stability, chemical resistance and creep resistance. Said polymer blends are suitable for use in the preparation of a variety of molded utilitarian articles having good appearance and paintability.

Abstract: An emulsion having a dye developing property, comprising aqueous polymer emulsion particles and contained therein, an organic dye developer.

Abstract: The optical fibre element comprises at least one optical fibre housing constituted by a polyolefin material having at least one additive which protects it against degradation due to oxidation, heat or the proximity of metals, and (b) at least one H.sub.2 -absorbing buffer. The additive is selected from the group comprising anti-oxidants, stabilizers and metal deactivators which cause a reduction in the hydrogen absorption capacity of less than 30% in the, or each, H.sub.2 -absorbing buffer when the, or each, buffer has been in contact with said polyolefin containing the, or each, additive for 30 days at 100.degree. C. in an air atmosphere saturated with water vapor at 150 mbar.

Abstract: The invention is a composition containing a polymer formed by side ring opening of an arylcyclobutene compound and an effective amount of an antioxidant.

Abstract: Improved resin compositions for use in multiple cavity stretch blow molding processes comprising: (a) a propyleneethylene copolymer resin including from about 5% to about 15% of a second stage polymer characterized by a cycle time of T.sub.1, when used to produce containers in multiple cavity stretch blow molding processes; (b) from about 0.1% to about 1.0% of a nucleating agent prepared by irradiating in air a mixture of a propylene homo or copolymer and about 500 to about 3000 ppm of antioxidant with a sufficient amount of ionizing radiation to cause said nucleating agent to have a xylene insoluble content of at least 30%. The improved resin composition is characterized by a cycle time of T.sub.2 when used to produce containers in multiple cavity stretch blow molding processes such that the ratio of T.sub.2 /T.sub.1 is less than 0.95.

Abstract: The present invention provides: a novel poly(arylene sulfide) (PAS) composition having an increased comparative tracking index (CTI) rating; a novel method wherein the inventive composition is formed and molded to produce a useful article; a novel article produced by the inventive molding method; a novel method wherein the inventive composition is formed and used to encapsulate an article; and a novel encapsulated article produced by the inventive encapsulation method. The inventive PAS composition comprises: poly(arylene sulfide) resin; talc; and an amount of hindered phenol sufficient to increase the composition's CTI rating.

Abstract: The present invention relates to the use of nucleus-substituted 4-hydroxyphenyl propionic acid compounds for stabilizing organic polyisocyanates.

Abstract: Stable dispersions of polyols having a viscosity lower than 10,000 mPa.times.sec and containing dispersed particles of polyvinylchloride, having a size within the range of from 1 to 10 micrometers and impregnated by the said polyols.

Abstract: Waxy esters of aromatic alcohols with long-chain carboxylic acids give lubricants and release agents for highly transparent thermoplastics which reduce the transparency of these plastics to a far lesser degree than the previously customary montan wax esters of aliphatic alcohols.

Abstract: Disclosed are a material for extrusion molding comprising a styrene-based polymer having a high degree of syndiotactic configuration, a melt viscosity of 10.sup.3 to less than 10.sup.6 poise measured at 300.degree. C. and a shearing rate of 10/sec, and a crystallinity of 15% or more, a process for preparation of the said material and a process for preparation of a molding product therefrom.The molding product prepared according to the present invention has excellent properties such as heat resistance and chemical resistance.

Abstract: A stabilized thermoplastic resin composition is provided which comprises the following components (i), (ii) and (iii):(i) 100 parts by weight, based on the total amount of the following (A), (B) and (C), of a mixture comprising (A) about 10-100% by weight of a polyphenylene ether, (B) 0-about 90% by weight of an alkenyl aromatic resin, and (C) 0-about 90% by weight of a crystalline thermoplastic resin, total amount of (A) and (B) being at least about 15% by weight of the total amount of (A), (B) and (C),(ii) 1-50 parts by weight of an alkenyl aromatic elastomer (non-hydrogenated), and(iii) a stabilizer comprising (D) 0.01-5 parts by weight of a sulfur compound and (E) 0.01-5 parts by weight of at least one phenol compound.

Abstract: Premoulding materials having long-term controllable B-stage characteristic, comprising phenol resins, optionally with reagents, additives and adjuvants, are characterized in that they contain hydraulic binder and/or its components as well as an agent that reduces the alkalinity and optionally the content of free metal ions. For its preparation, 1 part by wt. phenol resin is mixed with less than 4 parts by wt. of a hydraulic binder and/or its components as well as less than 0.2 equivalent parts by weight of the agent. The phenol resin premoulding materials according to the invention thicken quickly to a desired B-stage, are capable of maintaining the attained plateau, and thus allow the manufacture of heat-curable composites of desired rheology and reactivity.

Abstract: This invention relates to thermoplastic molding compositions, particularly thermoplastic polyesters, having incorporated therein a fluorinated polyolefin to improve wear resistance. More particularly, disclosed are polyester compositions having improved wear resistant good properties comprising a polyester resin, most preferably a poly(butylene terephalate) resin; a fluorinated polyolefin compound and a hindered phenolic compound and an ester compound, the last two components serving as a migrator package that serves to push a disproportionate amount of the fluorinated polyolefin within the subsurface of the resulting composition to thereby augment the wear resistant effect of the fluorinated polyolefin.

Abstract: The present invention comprises novel single-functional and mixtures of multi-functional oligomeric performance additive compounds having one or more components of Structure A R1 ? ? ##STR1## (The definitions of R, Z1, Z2, Z3, A1, A2, A3 and y are given in the Summary Section), their uses and polymeric compounds and compositions containing them which have enhanced oxidative stabilities, enhanced ultraviolet (UV) and light stabilites and/or enhanced flame retardance. An example is the bis sulfonic acid bispotassium salt reaction product from an oligomeric caprolactone diol (TONE.RTM. 260), 2-sulfobenzoic acid anhydride and potassium carbonate, and use of this product, at levels up to about 3.0%, in a general purpose bisphenol A polycarbonate resin, to enhance the fire resistance or flame retardance of the polycarbonate resin.

Abstract: Disclosed are olefin polymers in nonextruded, aspolymerized particle form having a regular, essentially symmetrical geometrical shape, which are stabilized by depositing on their surface a mixture which is either melted, or in which at least stabilizer (A) is in the liquid state, and which comprises the following stabilizers (percent by weight on the polymer):A) from 0.02% to 0.015% of one or more organic phosphites or phosphonites or mixtures thereof, which are liquid at room temperature or have melting point below 100.degree. C.;B) from 0.025% to 0.2% of one or more phenolic antioxidants with melting point from 45.degree. to 130.degree. C.; and, optionally, one or more of the following additional components:C) from 0.05% to 0.5% of one or more thioethers, or organic polysulfides or mixtures thereof;D) from 0.1% to 1.0% of one or more light stabilizers which are liquid at room temperature or have a melting point below 150.degree. C.

Abstract: Disclosed is an olefin polymer-based thermoplastic elastomer comprising a propylene polymer material, an amorphous olefin copolymer rubber, and optionally a semicrystalline, essentially linear ethylene-C.sub.3-4 alpha-olefin copolymer, having incorporated therein zinc salts of certain mercapto compounds and sterically hindered di-tertiary butyl phenol compounds. The compositions exhibit good retention of properties at elevated temperatures.

Abstract: A stabilizing composition for thermoplastic organic polymers containing measured quantities of: (a) a sterically hindered phenol; (b) a triarylphosphite; and (c) a dialkylthiodipropionate. Stabilized polymer compositions are also described containing a thermoplastic organic polymer, in particular a polyolefin, and a stabilizing quantity of said stabilizing composition, which possess excellent characteristics in relation to their melt flow index and color when subjected to repeated extrusion and in relation to their long-term thermal stability.

Abstract: Thermoplastic compositions comprising polyphenylene ethers and polyesters, impact-modified by glycidyl (meth)acrylate grafted EPDM and compatibilized by an aromatic polycarbonate exhibit high impact strength alone and when combined with other impact modifiers. Their shear sensitive viscosity properties makes them uniquely suitable for extrusion and blow molding applications.

Abstract: Substituted 1,3,2-benzoxazaphospholidines of formula I ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are independently hydrogen, alkyl, cycloalkyl, phenylalkyl or aryl, n is 1 to 4, and T is an n-valent aliphatic or aromatic hydrocarbon radical are effective in stabilizing organic materials against the deleterious effects of oxygen, heat and actinic radiation.

Abstract: Compounds of formula I ##STR1## wherein n is 2-4, R.sub.1 is alkyl, cycloalkyl, phenylalkyl, phenyl or a radical of formula II ##STR2## R.sub.2, R.sub.3 and R.sub.4 are independently hydrogen, alkyl, cycloalkyl, phenylalkyl or aryl, or R.sub.3 and R.sub.4 together are alkyl, R.sub.5 and R.sub.6 are independently hydrogen, alkyl, cycloalkyl or phenylalkyl, R.sub.7 is hydrogen, alkyl or a group of the formula --(CH.sub.2).sub.k COOR.sub.8, where k is 0-2 and R.sub.8 is hydrogen or alkyl, and T is an n-valent hydrocarbon radical which may be interrupted by heteroatoms, are useful stabilizers for substrates subject to the deleterious effects of oxygen, heat and/or actinic radiation.

Abstract: Substituted 3H-1,3,2-oxazaphospholidines of formula I ##STR1## where R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independently hydrogen, alkyl, cycloalkyl, phenylalkyl or aryl, n is 1 to 4 and T is an n-valent aliphatic or aromatic hydrocarbon radical are effective in stabilizing organic materials against the deleterious effects of oxygen, heat and/or actinic radiation.

Abstract: The invention relates to free-flowing polyamide molding compounds which are characterized by a content of new liquid-crystalline compounds corresponding to general formulae (I) and/or (II) and to the new liquid-crystalline compounds corresponding to general formulae (I) and/or (II).

Abstract: A stabilized polyethylene composition containing catalyst residues comprising at least one transition metal comprises (a) polyethylene, (b) 100 to 2000 ppm by weight based on the total weight of the composition of one or more antioxidants of the phenolic type and (c) 100 to less than 2000 ppm by weight, based on the total weight of the composition of zinc oxide but substantially no calcium stearate. The composition has improved color and improved resistance to coloration effects.

Abstract: Polyoxymethylene molding compositions include a polyoxymethylene base resin and contain, based upon the weight of the polyoxymethylene base resin, between 0.01 to 5% by weight of a hindered phenolic antioxidant, and between 0.01 to 5% by weight of an amine polymer having a molecular weight of at least 1000 and comprised essentially of structural units of the following formula (1): ##STR1## wherein R represent a hydrogen atom, an alkyl group, a phenyl group, an alkyl-substituted phenyl group, an NH.sub.2 group directly bonded to the carbon atom, or --X--NH.sub.2 -- where X represents an alkylene group, a carbonyl group, a carboxyalkylene group, an alkyleneoxycarbonylalkyl group, a phenylene group, an alkyl-substituted phenylene group, an amido group or an alkyleneamido group.

Abstract: A compound represented by the formula of: ##STR1## wherein R is hydrogen or methyl. This compound is useful as a stabilizer for butadiene polymers.

Abstract: Disclosed are films, containers and container liners comprising a copolyester having repeat units from terephthalic acid and 1,4-cyclohexanedimethanol, and a hindered phenolic antioxidant.

Abstract: A weather-resistantt polyacetal molding composition are comprised of a polyacetal base resin, and a weather-resistance effective amount of a stabilization package which includes (i) a weather stabilizer for the polyacetal base resin, (ii) an acrylic resin, and (iii) an oxyalkylene polymer comprised of repeating oxyalkylene units each having 2 to 8 adjacent carbon atoms.

Abstract: A composition comprising (A) (i) a crosslinked organosilicon polymer or crosslinkable organosilicon prepolymer comprising alternating (a) cyclic polysiloxane or tetrahedral siloxysilane residues and (b) polycyclic hydrocarbon residues derived from polycyclic polyenes having at least two non-aromatic, non-conjugated carbon-carbon double bonds in their rings linked through carbon to silicon bonds, wherein at least one of the cyclic polysiloxanes or tetrahedral siloxysilanes (a) or the polycyclic polyenes (b) used to form the polymer or prepolymer has more than two reactive sites; or (ii) a crosslinked or crosslinkable linear poly(organohydrosiloxane) polymer having at least 30% of its .tbd.

Abstract: Talc filled thermoplastic polyester compositions which have been modified by the addition of a butadiene-based impact modifier are stabilized against degradation by the addition thereto of a specific phosphorous compound.

Abstract: A fiber-reinforced polymer composition containing resin components including (a) 30-90 weight % of a polyamide resin, and (b) 10-70 weight % of polyolefin+unsaturated carboxylic acid-modified polyolefin, based on the resin components; and, per 100 parts by weight of the total components, (c) 5-50 parts by weight of glass fibers, and (d) additives including the following set of additives: 0.1-1 parts by weight of N,N'-hexamethylene-bis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide); 0.1-1 parts by weight of triethylene glycol-bis [3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate]; and 0.1-1 parts by weight of pentaerythrityl-tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]. An alternative set of additives are 0.1-2 parts by weight of N,N'-bis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine; 0.05-0.5 parts by weight of pentaerythrityl-tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]; 0.05-0.5 parts by weight of distearyl-pentaerythritol diphosphite; and 0.

Abstract: Stabilizing, synergistically acting mixtures of phenolic antioxidants and sulphur-containing elastic-thermoplastic graft products having terminal thioalkyl groups.

Abstract: Disclosed herein is a food container of a resin composition composed of a polyolefin and an inorganic filler, said resin composition containing (i) a phenolic antioxidant and (ii) a slip agent and/or antistatic agent, said phenolic antioxidant being at least one kind selected from .beta.-(4-hydroxy-3-t-butyl-5-alkylphenyl)propionic acid esters, hindered phenols having an isocyanuric acid ester, 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, specific phenol compounds, and 6-hydroxychroman compounds. The food container has a low level of offensive odors and discoloration.

Abstract: A composition comprises a thermoplastic or polymeric resin; an organic peroxide; and an organic sulfide antioxidant represented by Formula I, II or III: ##STR1## wherein m, n, r, R.sup.1, R.sup.2, R.sup.3, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are as set forth in the Summary of the Invention.

Abstract: A polyoxymethylene molding composition which exhibits improved ambient and heat aged color stability includes a metal deactivator and calcium hydroxystearate. One preferred composition of the invention includes: (a) greater than about 95 weight percent of polyoxymethylene, (b) between about 0.01 to about 0.1 weight percent of 3 salicyloyl-amido-1,2,4 triazole or tris-2-tert.butyl- 4-thio-(2'methyl-4'hydroxy-5'tert.butyl) phenyl-5-methyl phenyl phosphite, (c) between about 0.015 to about 0.4 weight percent of 2,4,6-triamino-sym-triazine, (d) between about 0.25 to about 1.0 weight percent of tetrakis(methylene-(3,5-di-tert-butyl- 4-hydroxyhydrocinnamate)) methane, (e) between about 0.05 to about 0.2 weight percent of calcium 12-hydroxystearate, and (f) between about 0.1 to about 0.3 weight percent of N-N'-ethylenebisstearamide. Due to their enhanced color stability, the compositions of this invention find particular utility as molded automobile components.

Abstract: Weather-resistant polyacetal resin compositions and molded articles formed of the same include a polyacetal base resin, and a weather-resistant effective amount of a weather stabilizing package comprised of (i) a weather stabilizer that is at least one selected from the group consisting of benzotriazoles, benzophenones, aromatic benzoates, cyanoacrylates, oxalanilides and hindered amines (ii) a homopolymer or copolymer of acrylic or methacrylic acid, or ester derivatives thereof, and (iii) a fluororesin.

Abstract: The present invention is a composition comprising crosslinked polyolefin resins and an amount of organic sulfide antioxidants sufficient to stabilize the resin against thermal or oxidative degradation, wherein the organic sulfide antioxidant is represented by Formula I, II or III ##STR1## wherein m, n, R, R.sup.1, R.sup.2, R.sup.3, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are as set forth in the Summary of the Invention.

Abstract: Incorporation into polyacetal molding compositions stabilized for processing with a non-meltable polymer stabilizer of 0.01-1.00 weight percent of at least one meltable co-stabilizer, said co-stabilizer being a thermal stabilizer for polyacetal, and 0.02-1.0 weight percent of at least one primary antioxidant results in significantly improved long term stability, as evidenced by greater retention of physical properties over time, of such compositions.

Abstract: Substituted aminoxy propionamide derivatives corresponding to the formula ##STR1## said derivatives being useful as color improvers and stabilizers in various polymeric substrates.

Abstract: A stabilized melt processable composition containing a halopolymer (e.g., an ethylene chlorotrifluoroethylene copolymer) and an effective stabilizing amount of an ester of a (4-hydroxy-5-alkylphenyl) alkanoic acid and at least one phosphite. Such compositions may be melt processed and extruded at high temperatures (e.g., up to 305.degree. C.) and retain their stability. These compositions are especially desirable in wire and cable coating applications.

Abstract: A stabilized resin composition comprising a resin, a piperidine derivative represented by the formula (III) ##STR1## wherein R.sub.1 is a hydrogen atom or an alkyl group having 1 to 3 carbom atoms; R.sub.2 is a hydrogen atom or an alkyl group having from 1 to 2 carbon atoms; and R.sub.3 and R.sub.4 are each independently an alkyl group having 1 to 12 carbon atoms, a phenol-type antioxidant and a sulfur-containing antioxidant. The composition simultaneously meets heat resistance, oxidation resistance and light resistance requirements.

Abstract: A butadiene polymer composition containing a phenolic compound represented by the formula: ##STR1## wherein R.sub.1 is an alkyl having 1 to 4 carbon atoms;R.sub.2 and R.sub.3 are each independently a group represented by --C(CH.sub.3).sub.2 --R' in which R' is an alkyl having 1 to 5 carbon atoms or phenyl, andR.sub.4 is hydrogen or methyl,and a sulfur-containing compound represented by the formula:(R.sub.5 --S--CH.sub.2 CH.sub.2 COOCH.sub.2).sub.4 Cwherein R.sub.5 is an alkyl having 4 to 20 carbon atoms. The composition is stable against the thermal deterioation and discoloration in the absence of oxygen as well as against the thermal and oxidative deterioration in the presence of oxygen.

Abstract: A butadiene polymer composition containing a phenolic compound represented by the formula: ##STR1## wherein R.sub.1 is an alkyl having 1 to 4 carbon atoms, R.sub.2 and R.sub.3 are each independently a group represented by --C(CH.sub.3).sub.2 --R' in which R' is an alkyl having 1 to 5 carbon atoms or phenyl, and R.sub.4 is hydrogen or methyl, and a phosphorus-containing compound represented by the formula: ##STR2## wherein R.sub.5 and R.sub.6 are each independently an alkyl having 1 to 9 carbon atoms.The composition is stable against the thermal deterioration and discoloration in the absence of oxygen as well as against the exposure to oxides of nitrogen gas.