Stabilizers for Synthetic Polymers Comprising 2,2,6,6-Tetramethyl-4-Piperidyl Carboxylic Acid Ester, a Triphosphite, and an Acid Phosphite or Salt Thereof

Hindered 2,2,6,6-tetraalkyl-4-carboxylic acid ester piperidine compounds have been proposed by Murayama et al U.S. Pat. No. 3,640,928 patented Feb. 8, 1972 as light and heat stabilizers for synthetic polymers, such as polyolefins, polyvinyl chloride, polyvinylidene chloride, polyurethanes, and polyamides. These compounds have the general formula: ##STR4## OR A SALT THEREOF.

In the above Formula:

R.sub.1 and R.sub.2 which may be the same or different, each are an alkyl group such as methyl, ethyl, isopropyl or dodecyl, or they form, together with the carbon atom to which they are attached, a saturated alicyclic group such as: ##STR5## or a group of the formula ##STR6##

n is an integer of 1 to 3 inclusive: and

R.sub.3 is an acyl group.

These compounds have proved to be particularly acceptable because they do not impart a discoloration of their own to the synthetic polymer. The compounds generally employed previously have either been highly colored, such as the nickel compounds (which are normally green) and the 2-hydroxybenzophenones (which are varying shades and intensities of yellow). They also show very little tendency towards sublimation and exudation, and they have an excellent stabilizing action against both heat and light deterioration.

Consequently, the Murayama et al patent has been followed by a large number of patent and literature disclosures by Murayama et al and others of compounds including a 2,2,6,6-tetrasubstituted-4-piperidyl group attached to a base molecule of varying structures.

Murayama et al. U.S. Pat. No. 3,898,303 patented Aug. 5, 1975 propose piperidino-spiro-hydantoin derivatives having the formula: ##STR7## wherein

R represents an alkyl group, an alkenyl group, an alkenoyl group which may be substituted with an aryl group, a hydroxyalkyl group, an alkoxyalkyl group, an alkoxycarbonylalkyl group, an acyloxyalkyl group, a cyanoalkyl group or nitroso group, and X and Y individually represent oyxgen atom or sulfur atom.

Murayama et al. in U.S. Pat. No. 3,899,464 patented Aug. 12, 1975 disclose a variation of the piperidino spiro compounds having the formula: ##STR8## wherein

R.sub.1 represents hydrogen atom, an alkyl group, a substituted alkyl group, an alkenyl group, an alkynyl group, a substituted or unsubstituted aralkyl group, an aliphatic acyl group, an alkoxycarbonyl group or an aralkoxycarbonyl group, n is an integer of 1 to 4;

when n is 1, R.sub.2 represents hydrogen atom, an aliphatic, aromatic or heterocyclic monoacyl group, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group, an alkoxyalkyl group, an epoxyalkyl group, an alkoxysulfonylalkyl group, N-substituted carbamoyl group, a N-substituted thiocarbamoyl group, a monovalent group from an oxoacid or group ##STR9## in which

R.sub.3 represents hydrogen atom, a lower alkyl group or phenyl group and R.sub.4 represents an alkyl group;

when n is 2, R.sub.2 represents carbonyl group, an aliphatic or aromatic diacyl group, an alkylene group, an alkenylene group, an alkynylene group, an aralkylene group, a N-substituted dicarbamoyl group or a divalent group from an oxoacid;

when n is 3, R.sub.2 represents an aromatic triacyl group or a trivalent group from an oxoacid; and

when n is 4, R.sub.2 represents an aromatic tetraacyl group, and A represents a group ##STR10## in which

R.sub.5 represents hydrogen atom or a lower alkyl group or, when n is 1, R.sub.5 may represent together with R.sub.2 a group ##STR11## in which

R.sub.6 represents the same group as defined in R.sub.1 and may be the same or different from R.sub.1, or a group ##STR12## in which

m is 1 or 2 and R.sub.7 represents hydrogen atom or, when n and m are 1, R.sup.7 represents methylene group together with R.sub.2.

Murayama et al. U.S. Pat. No. 3,933,735 patented Jan. 20, 1976 propose 4-piperidone derivatives having a structure similar to the 4-piperidyl derivatives, but with a keto oxygen at the 4-position of the piperidine ring.

Murayama et al. U.S. Pat. No. 3,941,744 patented Mar. 2, 1976, disclose another variation of the piperidino spiro derivatives having the formula: ##STR13## wherein

R' represents an alkyl group, a substituted alkyl group, an acyl group, an alkoxycarbonyl group, a substituted alkoxycarbonyl group, an amino group, a substituted amino group or nitroso group;

X represents oxygen atom or sulfur atom;

Y represents oxygen atom, sulfur atom or a group of the formula .dbd. N--R" in which R" is hydrogen atom, an alkyl group or a substituted alkyl group;

Z represents oxygen atom or a group of the formula > N--R"' is hydrogen atom, an alkyl group or a substituted alkyl group;

n is an integer of 1 through 4 inclusive; and

R represents, when n is 1, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, a cycloalkyl group, an alkoxycarbonyl group, a substituted alkoxycarbonyl group, a substituted phosphino group or a substituted phosphinyl group, when n is 2, an alkylene group, an alkenylene group, an arylene group, a substituted arylene group, an aralkylene group, an alkylenediphenylene group, a bis-(acyloxyalkylene) group, an alkylene-bis-(oxycarbonylalkyl)group, a dialkylene ether group or a diphenylene ether group, when n is 3, an alkanetriyl group, a tris-(acyloxyalkylene)group, an alkane-tris-(oxycarbonylalkyl)group or a group of the group ##STR14## in which

p is an integer of 1 through 8 inclusive, and when n is 4, an alkane tetrayl group, a tetrakis-(acyloxyalkylene)group or an alkanetetrakis-(oxycarbonylalkyl) group.

Murayama et al. U.S. Pat. No. 3,940,363 patented Feb. 24, 1976 disclose a further variation in which two 2,2,6,6-tetrasubstituted-4-piperidyl groups are linked together via the ring nitrogen atom to an R' alkylene linking group, which may be interrupted with an oxygen or sulfur atom, an alkenylene group, an alkynylene group, an aralkylene group, an aliphatic diacyl group, a group having the formula: ##STR15## in which

n is an integer of 1 or 2 and X is an alkylene group, or o-, m- or p-phenylene group or the carbon atoms of CO groups may be directly joined in the absence of X or a group of the formula: ##STR16## in which

Y is an alkylene group or o-, m- or p-phenylene group.

Ramey et al. U.S. Pat. Nos. 3,899,491, patented Aug. 12, 1975 and 3,920,659, patented Nov. 18, 1975, disclose alkyl alkanoate derivatives of substituted piperazines and substituted piperazinodiones. The substituted piperazines of U.S. Pat. No. 3,899,491 have the formula: ##STR17## wherein

R.sup.1 and R.sup.2 are methyl or together with the carbon to which they are bound form a mono-cyclic ring system having five or six carbon atoms;

R.sup.3 is an alkyl group of from one to twenty atoms;

R.sup.4 is hydrogen or methyl, and

m is 0 or 1.

The substituted piperazinodiones of U.S. Pat. No. 3,920,659 have the formula: ##STR18## wherein

R.sup.1 and R.sup.2 are independently of each other methyl or ethyl or together with the carbon to which they are bound form a cyclopentyl or cyclohexyl ring, which is unsubstituted or substituted with a methyl group;

n is an integer of from 1 to 2;

when n is 1, R.sup.3 is an alkyl group of from one to 20 carbon atoms;

when n is 2, R.sup.3 is an alkylene group of from two to eight carbon atoms; and

A is a straight or branched chain (lower)alkylene group containing from one to six carbon atoms with the limitation that the terminals of said alkylene group bear only hydrogen or one (lower) alkyl group.

Ramey et al. U.S. Pat. No. 3,920,661 patented Nov. 8, 1975 disclose dicarboxylic acids and salts in which one carboxylic acid group is esterified with a 2,2,6,6-tetrasubstituted-4-hydroxy piperidine and having the formula: ##STR19## wherein

R.sub.1 and R.sub.2 independently of each other are straight- or branched-chain alkyl having from one to six carbon atoms, or together with the carbon to which they are bound form a cyclopentyl or cyclohexyl ring, which is unsubstituted or substituted with a methyl group;

R.sub.3 is hydrogen, alkyl having one to 12 carbon atoms, .beta.-methoxyethyl, alkenyl having three or four carbon atoms, propargyl, benzyl or alkyl-substituted benzyl;

R.sub.4 is straight or branched-chain alkylene having five to eight carbon atoms, or the group (CH.sub.2).sub.m Y(CH.sub.2).sub.n wherein Y is oxygen or sulfur and m and n independently of each other are an integer from 1 to 3;

M is hydrogen or a metal selected from the group consisting of barium, nickel, manganese, calcium, zinc, iron, sodium, cobalt, tin, and dialkyl tin, and

z has a value of from 1 to 4, the value of z being the same as the available valence of M.

Ramey et al. U.S. Pat. No. 3,939,163 patented Feb. 17, 1976 disclose closely similar compounds in which R.sub.4 is alkylene having from one to four carbon atoms.

Randell et al. U.S. Pat. No. 3,939,170 patented Feb. 17, 1976 disclose dehydropyrindinyl sulphides, sulphoxides and sulphones having the formula: ##STR20## wherein

X is S, SO or SO.sub.2 and Y and Y.sup.1 are the same or different and each is H, OH, O-- or a straight- or branched alkyl residue having from one to four carbon atoms, and salts thereof when Y and Y.sup.1 are other than O--.

Randell et al. in published patent application No. B408,123 published Apr. 13, 1976 disclose substituted piperidine-4-ols having the formula: ##STR21## wherein

R.sup.1 and R.sub.2 are the same or different and each is a straight- or branched alkyl residue having from one to twelve carbon atoms, or R.sub.1 and R.sub.2, together with the carbon atom to which they are attached, form a cycloalkyl residue having from five to twelve carbon atoms or the group: ##STR22## wherein

R.sub.1 and R.sub.2 have their previous significance and Y is a straight- or branched alkyl residue having from one to twenty carbon atoms, an alkenyl or alkynyl residue having from three to twenty carbon atoms, an aralkyl residue having from seven to twelve carbon atoms or the group --CH.sub.2 X wherein X is the group ##STR23## wherein

R.sub.3 is hydrogen, a methyl or phenyl residue, the group ##STR24## wherein

R.sub.4 is an alkyl residue having from one to 20 carbon atoms.

Cook U.S. Pat. No. 3,929,804 patented Dec. 30, 1975 discloses 4-piperidine acetamide compounds having the formula: ##STR25## wherein

R.sub.1 and R.sub.2 are the same or different and each is a straight- or branched alkyl residue having from one to twelve carbon atoms, or R.sub.1 and R.sub.2, together with the carbon atom to which they are attached form a cycloalkyl group having from 5 to 12 carbon atoms;

R.sup.3 is hydrogen, a straight- or branched alkyl residue having from one to four carbon atoms, an aralkyl residue having from seven to nine carbon atoms or a cycloalkyl group having from five or six carbon atoms;

R.sub.4 is a metal ion or a hydrocarbyl residue having from two to twenty carbon atoms and being either unsubstituted or substitutd by halogen or interrupted by one or more oxygen or sulphur atoms;

X is --O--, --S--, or >NR.sub.5, wherein R.sub.5 has the same significance as R.sub.3 ; and

n is 2, 3 or 4;

as well as salts of the amine function of the compounds of formula I.

Cook U.S. Pat. No. 3,939,168 patented Feb. 17, 1976 discloses closely similar compounds having a Y substituted on the piperidyl nitrogen atom, Y being alkyl, alkenyl, aralkyl or a group ##STR26## wherein

R.sub.7 is hydrogen, alkyl or phenyl.

In accordance with the instant invention, stabilizers for organic polymeric materials are provided, comprising a triphosphite, and acid phosphite, and a 2,2,6,6-tetramethyl-4-piperidyl carboxylic acid ester having the general formula: ##STR27## wherein:

R.sub.1 is selected from the group consisting of ##STR28##

Y is selected from the group consisting of hydrogen and O;

R.sub.6 is lower alkyl having from one to six carbon atoms;

n is selected from the group consisting of 1, 2, 3 and 4; and

Z is an organic radical having a valence from 1 to 4, the valence positions being taken by ##STR29## groups, and from one to about 20 carbon atoms, and selected from the group consisting of alkyl, alkenyl, alkylene, alkenylene, alkylidene; aryl, arylene, aralkyl, aralkylene, aralkylidene, alkaryl, alkarylene, alkarylidene; heterocycloalkyl, heterocycloalkylene, heterocycloalkylidene; cycloalkyl, cycloalkenyl, cycloalkylene, cycloalkenylene, cycloalkylidene, alkycycloalkyl, alkcycloalkenyl, alkcycloalkenylene, alkcycloalkylene, cycloalkalkylene, cycloalkalkyl, cycloalkalenyl, and cycloalkalkenylene, and amino- and hydroxy-substituted such radicals.

The R.sub.6 alkyl have from one to six carbon atoms, and the Z alkyl and alkenyl have from one to about twenty carbon atoms. Exemplary are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tertiary butyl, secondary butyl, n-amyl, isoamyl, tertiary amyl, n-hexyl, isohexyl, secondary hexyl, tertiary hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, isononyl, decyl, dodecyl, tridecyl, tetradecyl, hexacecyl, octadecyl, and eicosyl; allyl, butenyl, oleyl, ricinoleyl and linoleyl.

The Z alkylene, alkenylene and alkylidene have from one to twenty carbon atoms, and include saturated and unsaturated methylene, ethylene, propylene, butylene, amylene, hexylene, heptylene, octylene, nonylene, decylene, dodecylene, and octadecylene; vinylene, ethylidene, propylidene, butylidene, hexylidene and octylidene.

The Z aryl and arylene have from six to about twenty carbon atoms and include phenyl, napthyl and phenanthryl; phenylene, naphthylene and phenanthrylene.

The Z aralkyl and aralkylidene have from seven to about 20 carbon atoms, and include phenmethyl, phenethyl, phenpropyl, phenbutyl and napthethyl.

The Z heterocyclic alkyl, heterocycloalkylene and heterocycloalkylidene have heterocyclic rings with from three to six ring atoms of which from one to three are selected from nitrogen, sulfur and oxygen, and the remainder, if any, are carbon, with one or more alkyl, alkylene or alkylidene substituents, and include piperidine, piperazine, pyrrole, pyrazoline, pyrrollidine, melamine, isocyanuric acid, triazine, pyrazine, pyridone, pyridazine, hexahydropipyrazine, pyrimidine, and hexayhydropyrimidine.

The Z cycloalkyl, cyclolkenyl, cycloalkylene, cycloalkenylene and cycloalkylidine, cycloalkalkyl and alkcycloalkyl have from three to 20 carbon atoms and include a cycloaliphatic ring of from three to eight carbon atoms in a monocyclic or bicyclic structure, optionally with an alkyl or alkylene substituent, and include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, bicyclic cycloheptyl, bicyclic cyclooctyl, methyl cyclopentyl, methyl cyclohexyl, cyclohexylidene, cyclopentylidene, cyclohexylene and cycloheptylene.

Amino-substituted Z radicals include nitrilo trimethylene, ethylene diamine tetramethylene, and nitrilo dimethylene ethylene.

It will be apparent that the Z radical is the residue of a mono or polycarboxylic acid all of whose carboxylic acid groups are esterified by R.sub.1 groups, which can be the same or different. The following compounds are exemplary: ##STR30##

The 2,2,6,6-tetramethyl-4-piperidyl carboxylic acid esters are for the most part known compounds. All are readily prepared using conventional procedures. The starting materials are either available or readily synthesized without difficulty. The corresponding 2,2,6,6-tetramethyl-4-hydroxy piperidine is used as a starting material for the 2,2,6,6-tetramethyl-4-piperidyl group R.sub.1. This is reacted in the presence of an organic solvent and an alkali metal alkoxide with one or more free carboxylic acid groups of the corresponsing mono or polycarboxylic acid with a Z nucleus containing one or more unesterified carboxylic acid groups. The hydroxy groups of the piperidine becomes esterified with the free carboxylic acid groups, forming the 4-piperidinyl carboxylic acid ester of the invention: ##STR31##

Acids which can be used include acetic, propionic, butyric, valeric, capric, caproic, lauric, myristic, palmitic, and stearic; succinic, glutaric, malic, lactic, adipic, suberic, azelaic, pimelic, citric, trimellitic, pyromellitic, butane-1,2,3,4-tetracarboxylic acid, and cylopentane tetracarboxylic acid, nitrilotriacetic, ethylene diamine tetraacetic, benzoic, terephthalic, and phthalic.

The stabilizer mixtures of the invention in addition to the 2,2,6,6-tetramethyl-4-piperidyl carboxylic acid ester include an organic triphosphite and an acid phosphite. Such combinations are complementary, and impart an enhanced resistance of the polymer to deterioration when exposed to light and/or heat. Such stabilizing effectiveness is enhanced as compared to only one or two components of the three-component stabilizer mixtures of the invention.

A variety of organic triphosphites and acid phosphites can be employed, of which the following are exemplary.

The organic triphosphite can be any organic phosphite having three or more organic radicals attached to phosphorus through oxygen. The acid phosphite can be any organic phosphite having one or two organic radicals attached to phosphorus through oxygen. These radicals can be monovalent radicals, in the case of the triphosphites, diphosphites and monophosphites.

The organic tiphosphites in which the radicals are monovalent radicals can be defined by the formula: ##STR32## in which R.sub.1, R.sub.2 and R.sub.3 are selected from the group consisting of alkyl, alkenyl, aryl, alkaryl, aralkyl, and cycloalkyl groups having from one to about 30 carbon atoms.

The acid phosphites are defined by the same formula, but one or two of R.sub.1, R.sub.2 and R.sub.3 is hydrogen or a cation of a metal or ammonium.

Also included are the organic triphosphites having a bivalent organic radical forming a heterocyclic ring with the phosphorus of the type: ##STR33## in which R.sub.4 is bivalent organic radical selected from the group consisting of alkylene, arylene, aralkylene, alkarylene and cycloalkylene radicals having from two to about 30 carbon atoms, and R.sub.5 is a monovalent organic radical as defined above in the case of R.sub.1, R.sub.2 and R.sub.3.

R.sub.5 is hydrogen or a cation, in the case of the acid phosphites.

Also useful organic triphosphites are mixed heterocyclic-open chain phosphites of the type: ##STR34##

More complex triphosphites are formed from trivalent organic radicals, of the type: ##STR35## in which R.sub.6 is a trivalent organic radical of any of the types of R.sub.1 to R.sub.5, inclusive, as defined above.

A particularly useful class of complex triphosphites are the tetraoxadiphosphaspiro undecanes of the formula: ##STR36## wherein R.sub.1 and R.sub.2 are selected from the group consisting of aryl, alkyl, aryloxyethyl, alkyloxyethyl aryloxyethoxyethyl, alkyloxyethoxyethyl and alkyloxypolyethoxyethyl having from about one to about thirty carbon atoms.

In the case of the acid phospites, one or both of R.sub.1 and R.sub.2 is also hydrogen or a cation.

An espcially preferred class of organic triphosphites and acid phosphites have a bicyclic aromatic group attached to phosphorus through oxygen, with no or one or more phenolic hydroxyl groups on either or both of the aromatic rings. These phosphites are characterized by the formula: ##STR37## in which Ar is a mono or bicyclic aromatic nucleus and m is an integer of from 0 to about 5. Z is one or a plurality of organic radicals as defined above for R.sub.1 to R.sub.6, taken singly or together in sufficient number to satisfy the valences of the two phosphite oxygen atoms.

One or both Z radicals is also hydrogen, in the case of the acid phosphites, and can include additional bicyclic aromatic groups of the type (HO).sub.m --Ar.

The cation in the case of acid phosphites can be a metal, such as an alkali metal, for instance, sodium, potassium or lithium; an alkaline earth metal, for instance, barium, calcium, or a nontoxic polyvalent metal, such as magnesium, tin and zinc.

Usually, the triphosphites and acid phosphites will not have more than about sixty carbon atoms.

Exemplary triphosphites are monophenyl di-2-ethylhexyl phosphite, diphenyl mono-2-ethylhexyl phospite, di-isoocyl monotolyl phosphite, tri-2-ethylhexyl phosphite, phenyl dicyclohexyl phosphite, phenyl diethyl phosphite, triphenyl phosphite, tricresyl phosphite, tri(dimethylphenyl)phosphite, trioctadecyl phosphite, triisooctyl phosphite, tridodecyl phoshite, isooctyl diphenyl phosphite, diisooctyl phenyl phosphite, tri(t-octylphenyl) phosphite, tri(t-nonylphenyl) phosphite, benzyl methyl isopropyl phosphite, butyl dicresyl phosphite, isooctyl di(octylphenyl) phosphite, di(2-ethylhexyl) (isooctylphenyl)phosphite, tri(2-cyclohexylphenyl)phosphite, tri-.alpha.-naphthyl phosphite, tri(phenylphenyl)phosphite, tri(2-phenylethyl)phosphite, ethylene phenyl phosphite, ethylene t-butyl phosphite, ethylene isohexyl phosphite, ethylene isooctyl phosphite, ethylene cyclohexyl phosphite, 2-phenoxy-1,3,2-dioxaphosphorinane, 2-butoxy-1,3,2-dioxyphosphorinane, 2octoxy-5,5-dimethyl-dioxaphosphorinane, and 2-cyclohexyloxy-5,5diethyl dioxaphosphorinane.

Exemplary pentaerythritol triphosphites are 3,9-diphenoxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane (diphenyl-pentaerythritoldiphosphite), 3,9-di(decyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro (5,5)-undecane, 3,9-di(isodecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane, 3,9-di(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane, 3-phenoxy-9-isodecyloxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecan e, 3,9-di(methoxy)-2,4,8,10-tetraoza-3,9-diphosphaspiro-(5,5undecane,3,9-di(l auryloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane, 3,9-di-p-tolyloxy-2,4,8,10 tetraoxa-3,9-diphosphaspiro-(5,5)-undecane; 3,9-di(methoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecan e; 3-methoxyethyloxy-9-isodecyloxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5) -undecane; 3,9-di(ethoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane ; 3,9-di(ethoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecan e; 3-methoxyethyloxy-9-butoxyethyloxy-2,4,8,10-tetraoxa-3,9diphosphaspiro-(5, 5)-undecane; 3,9-di (methoxyethoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecan e; 3,9-di(butoxyethoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-un decane; 3,9-di(methoxyethoxyethoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-( 5,5)-undecane; 3,9-di(methoxy(polyethoxy)ethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro (5,5)-undecane (where the (polyethoxy) ethyloxy group has an average molecular weight of 350) 3,9di(methoxy (polyethoxy)ethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane (where the (polyethoxy)ethyloxy group has an average molecular weight of 550).

Exemplary of the bis aryl triphosphites are: bis(4,4'-thio-bis (2-tertiary butyl-5-methyl-phenol)) isooctyl phosphite, mono (4,4'-thio-bis (2-tertiary-butyl-5methyl-phenol)) di-phenyl phosphite, tri-(4,4'-n-butylidenebis(2-tertiary-butyl-5-methyl-phenol)) phosphite, (4,4'-benzylidene-bis (2-tertiary-butyl-5-methyl-phenol)) diphenyl phosphite, isooctyl 2,2'-bis (-parahydroxyphenyl)propane phosphite, decyl 4,4'-n-butylidene-bis (2-tertiary-butyl-5-methylphenol)phosphite, tri-4,4'-thiobis(2-tertiary-butyl-5-methylphenol) phosphite, 2-ethylhexyl-2,2' -methylene-bis(4-methyl-6,1'-methylcyclohexyl)phenol phosphite, tri (2,2'-bis-(para-hydroxyphenyl) propane) phosphite, tri (4,4'-thio-bis(2-tertiary-butyl-5methyl-phenol) phosphite, isooctyl-(2,6-bis(2'-hydroxy-3,5-dinonylbenzyl)-4-nonyl phenyl)) phosphite, tetra-tridecyl 4,4'-n-butylidene-bis(2-tertiary butyl-5-methyl penyl) diphosphite, tetra-isooctyl 4,4'-thiobis (2-tertiary butyl-5-methyl phenyl diphosphite, 2,2'-methylene-bis (4-methyl 6,1'-methyl cyclohexyl phenyl)polyphosphite, isooctyl-4,4'-isopropylidene-bis-phenyl-polyphosphite, 2-ethylhexyl-2,2'-methylene-bis(4-methyl-6,1'-methyl-cyclohexyl) phenyl triphosphite, tetra-tridecyl-4,4'-oxydiphenyl diphosphite, tetra-n-dodecyl-4,4'-n-butylidene bis (2-tertiary-butyl-5-methylphenyl) diphosphite, tetratridecyl-4,4'-iso-propylidene bisphenyl diphosphite, hexa-tridecyl butane-1,1,3-tris (2'-methyl-5'-tertiary-butylphenyl-4'-)triphosphite.

Exemplary acid phosphites are di(phenyl)phosphite, monophenyl phosphite, mono-(diphenyl)phosphite, dicresyl phosphite, di-(o-isooctylphenyl) phosphite, di(p-ethylhexylphenyl)phosphite, di(p-t-octylphenyl)phosphite, di(dimethylphenyl) phosphite, di-n-butyl phosphite, di-2-ethylhexyl phosphite, mono-2-ethylhexyl phosphite, diisoctyl phosphite, monoisooctyl phosphite, monododecyl phosphite, 2-ethylhexyl phenyl phosphite, 2-ethylhexyl(n-octylphenyl) phosphite, monocyclohexyl phosphite, dicyclohexyl phosphite, di(2-cyclohexyl phenyl) phosphite, di-.alpha.-naphthyl phosphite, diphenyl phenyl phosphite, di(diphenyl) phosphite, di-(2-phenyl ethyl) phosphite, dibenzyl phosphite, monobenzyl phosphite, n-butyl cresyl phosphite and didodecyl phosphite, cresyl phosphite, t-octylphenyl phosphite, ethylene phosphite, butyl cresyl phosphite, isooctyl monotolyl phosphite and phenyl cyclohexyl phosphite.

Exemplary of the bis aryl acid phosphites are: bis (4,4'-thio-bis (2-tertiary-butyl-5-methyl-phenol)) phosphite, (4,4'-thio-bis (2-tertiary-butyl-5-methyl-phenol)) phenyl phosphite, bis (4,4'-n-butylidene-bis (2-tertiary-butyl-5-methyl-phenol)) phosphite, amono (4,4'-benzylidene-bis (2-tertiary-butyl-5-methyl-phenol)) phosphite, mono (2,2'-bis-(-parahydroxyphenyl)propane) phosphite, mono (4,4'-n-butylidene-bis (-2-tertiary-butyl-5-methyl-phenol) phosphite, bis (4,4'-thiobis (2-tertiary-butyl-5-methylphenol)) phosphite, mono-2-ethylhexyl-mono-2,2'methylene-bis (4-methyl-6,1'methylcyclohexyl) phenol phosphite, bis(2,2'-bis-(para-hydroxyphenyl)propane) phosphite, monoisooctyl mono(4,4'thio-bis (2-tertiary-butyl-5-methyl-phenol)) phosphite, isooctyl-(2,6-bis (2'-hydroxy-3,5-dinonylbenzyl)-4-nonyl phenyl)) phosphite, tri-tridecyl 4,4'-n-butylidene-bis (2-tertiary-butyl-5-methyl phenyl) diphosphite, triiooctyl 4,4'-thiobis (2-tertiary-butyl-5-methyl phenyl) diphosphite, bis (2,2'-methylene-bis (4-methyl-6,1'-methyl cyclohexyl phenyl)) phosphite, isooctyl-4,4'-isopropylidene-bis-phenyl phosphite, monophenyl mono (2,2'-methylene-bis (4-methyl-6,1' 6,1'-methyl-cyclohexyl)) triphosphite, di-tridecyl-4,4'-oxydiphenyl diphosphite, di-n-dodecyl-4,4'-n-butylidene bis (2-tertiarybutyl-5-methylphenyl) diphosphite, di-tridecyl-4,4'-isopropylidene bisphenyl diphosphite, tetra-tridecyl butane-1,1,3-tris (2.degree.-methyl-5'-tertiary-butylphenyl-4-) triphosphite.

The 2,2,6,6-tetrasubstituted-4-piperidyl carboxylic acid ester-triphosphite-acid phosphite-containing stabilizer compositions of the invention are effective stabilizers to enhance the resistance to deterioration due to heat and/or light of synthetic polymeric materials which are susceptible to such degradation, including polyolefins such as low density polyethylene, high density polyethylene, polypropylene, polybutylene, polyisobutylene, polypentylene, and polyisopentylene, polystyrene; polydienes, such as polybutadiene and polyisoprene; and copolymers of olefins and dienes with other ethylenically and acetylenically unsaturated monomers, such as ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-pentene copolymers, ethylene-vinyl acetate copolymers, styrene-butadiene copolymers, acrylonitrilestyrene-butadiene copolymers, synthetic rubbers of all types, such as polychloroprene; polyvinyl halides, including polyvinyl chloride homopolymer, polyvinylidene chloride; and copolymers of vinyl chloride and vinylidene chloride; vinyl chloride and vinyl acetate; vinylidene chloride and vinyl acetate; and other ethylenically unsaturated monomers; polyacetals such as polyoxymethylene and polyoxyethylene; polyesters such as polyethylene glycol-terephthalic acid ester polymers; polyamides such as polyepsiloncaprolactam; polyhexamethylene adipamide and polydecamethylene adipamide; polyurethanes; and epoxy resins.

The synthetic polymer can be in any physical form, including (for example) filaments, yarns, films, sheets, molded articles, latex, and foam.

A sufficient amount of the stabilizer combination is used to improve the resistance of the synthetic polymer to deterioration in physical properties, including, for example, discoloration, reduction in melt viscosity and embrittlement, under the conditions to which the polymer will be subjected. Very small amounts are usually adequate. Amounts within the range from about 0.005 to about 5% total stabilizers by weight of the polymer are satisfactory. Preferably, from 0.05 to 2% is employed for optimum stabilization.

Preferably, the stabilizer system comprises from about 89.5 to about 30% of the 2,2,6,6-tetrasubstituted-4-piperidyl carboxylic acid ester, from about 69.5 to about 10% of the triphosphite, and from about 10 to about 0.5% of the acid phosphite by weight of the stabilizer system.

The stabilizer compositions of the invention can be employed as the sole stabilizers or, preferably, in combination with other conventional heat and light stabilizers for the particular synthetic polymer.

Thus, for example, in the case of polyvinyl chloride resins, other polyvinyl chloride resin heat stabilizers can be included, including polyvalent metal fatty acid salts such as barium and cadmium salts of the higher fatty acids; organotin compounds; hindered phenols; and epoxy compounds.

With polyolefin resins there can be employed fatty acid salts of polyvalent metals, phenolic antioxidants, and the higher fatty acid esters of thiodipropionic acids, such as, for example, dilauryl thiodipropionate.

With polyamide resin compositions, polyamide stabilizers such as copper salts in combination with iodides and/or other phosphorus compounds and salts of divalent manganese can be used.

With synthetic rubbers and acrylonitrile-butadiene-styrene terpolymers, antioxidants such as hindered phenols and bis-phenols and polyvalent metal salts of the higher fatty acids can be used.

In addition, other conventional additives for synthetic polymers, such as plasticizers, lubricants, emulsifiers, antistatic agents, flameproofing agents, pigments and fillers, can be employed.

The following Examples in the opinion of the inventors represent preferred embodiments of synthetic resin compositions in accordance with the invention.

A group of polyvinyl chloride resin compositions was prepared having the following formulation:

This formulation was blended and sheeted off on a two-roll mill to form sheets 1 mm thick. The light resistance of these sheets was then determined by placing strips 1 cm long in a Weather-O-Meter, and exposing them to ultraviolet light. The time in hours was then noted for the sheet to develop a noticeable discoloration and/or embrittlement, indicating deterioration due to oxidation in the presence of ultraviolet light (denoted as Hours to Failure in Table I).

Heat stability was evaluated in a Geer forced air oven at 175.degree. C, and the time to failure in minutes noted (denoted as Minutes to Failure in Table I).

This test was carried out for the stabilizers in accordance with the invention having the formulae indicated in Table I. The following results were obtained:

It is apparent that the stabilizer compositions in accordance with the invention are far superior to the controls containing no stabilizer or only one or two of the three-component stabilizer of the invention.

Polypropylene compositions were prepared using stabilizers of the invention and having the following formulation:

The composition was thoroughly blended in a Brabender Plastograph, and then compression-molded to form sheets 0.5 mm thick.

Pieces 2.5 cm square were cut off from the sheets and exposed to ultraviolet light in a Weather-O-Meter.

Heat stability was evaluated in an air circulating oven at 160.degree. C.

In each test, the time in hours required for the sheet to develop a noticeable discoloration and/or embrittlement was noted as the hours to failure.

The results obtained are shown in Table II.

It is apparent from the above results that the compounds of the invention are superior stabilizers in enhancing the resistance of the polypropylene polymer composition to deterioration in the presence of ultraviolet light.

Ethylene-vinyl acetate copolymer compositions were prepared using stabilizers of the invention and having the following formulation:

The stabilizer was blended with the polymer on a two-roll mill at 120.degree. C, and sheets 1 mm thick were then compression molded at 120.degree. C from the resulting blend. Pieces 2.5 cm square were cut off from the sheets and exposed to ultraviolet light in a Weather-O-Meter for 500 hours. At the start and at the conclusion of the test, the tensile strength of the sheet samples was determined.

Heat stability was evaluated in a Geer forced air oven at 175.degree. C. Initial color was determined using a Hunter color difference meter.

The results are given in Table III as % retention of the initially determined tensile strength, minutes to failure in the oven test, and intial yellowness: Oven Heating Minutes to % Rentention of Color Failure Ex. No. Piperidyl Compound Triphosphite Acid phosphite tensile strength (oven) Color Control 1 None None None 53 60 32 Control 2 None Tris(nonylphenyl) Di(nonylphenyl) 58 105 10 phosphite hydrogen phosphite Control 3 ##STR54## None Diphenyl hydrogenphosphite 75 45 22 Control 4 ##STR55## Tetra(C.sub.12-15 alkyl)4,4'-isopropylidenediphenol diphosphite None 73 75 19 13 ##STR56## Octyldiphenylphosphite Diphenyl hydrogenphosphite 80 105 11 14 ##STR57## Distearyl penta-erythritol di-phosphite Pentaerythritoldihydrogen diphosphite 83 120 8 15 ##STR58## Tris(nonylphenyl)phosphite Di(nonylphenyl)hydrogen phosphite 79 120 10 16 ##STR59## Trilaurylphosphite Dilauryl hydrogenphosphite Ni salt 82 105 1017 ##STR60## Tetra(C.sub.12-15 alkyl)4,4'-iso-propylidenediphenoldiphosphite Dibutyl hydrogenphosphite Ba salt 80 105 11 18 ##STR61## Tetra(tridecyl)-1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl) Diphenyl hydrogenphosphite 82 120 9

It is apparent from the results that the stabilizer compositions in accordance with the invention are superior in enhancing the resistance of the ethylene-vinyl acetate copolymer to deterioration in the presence of ultraviolet light, and at elevated temperature.

High density polyethylene compositions were prepared using five stabilizers of the invention and two of the prior art, and having the following formulation:

The stabilizer was blended with the polymer on a two-roll mill and sheets 0.5 mm thick were prepared by compression molding of the blend. Pieces 2.5 cm square were cut off from the sheets, and exposed in a Weather-O-Meter to ultraviolet light.

Heat stability was evaluated in a Geer oven at 150.degree. C.

In each case the time in hours when degradation set in, as determined by a significant discoloration and/or embrittlement, was noted as hours to failure, and the results are reported in Table VI: Hours to Failure Ex. (Weather- No. Piperidyl Compound Triphosphite Acid phosphite O-Meter) (Oven) Control 1 None None None 460 283 Control 2 None Distearyl penta- Stearyl pentaerythritol 480 662 erythritol di- hydrogen phosphite phosphite Control 3 ##STR62## None None 1050 214 Control 4 ##STR63## Phenyl diisodecylphosphite (0.01) Diisodecyl hydrogenphosphite (0.12) 630 286Control 5 ##STR64## Tris (nonylphenyl)phosphite None 970 345 19 ##STR65## Phenyl diisodecylphosphite Diisodecyl hydrogenphosphite 950 584 Control 20 ##STR66## Tris (nonylphenyl)phosphite Dibutyl hydrogenphosphite Zn salt 1080 59021 ##STR67## Hexa(tridecyl)-1,1,3-tris (2-methyl-4-hydroxy-5-t-butyl-phenyl)butanetri -phosphite Diphenyl hydrogenphosphite Na salt 1150 628 22 ##STR68## Bis(nonylphenyl)-4,4'-isopropylidenebis(2-t-butylphenyl)phosphite Di(nonylphenyl)hydrogen phosphite 1030 604 23 ##STR69## Distearyl penta-erythritol di-phosphite Stearyl pentaerythritolhydrogenp hosphite 1130 65124 ##STR70## Tetra(tridecyl)-4,4'butyldene bis(3-methyl-6-t-butylphenol)diphosphite Dilauryl hydrogenphosphite 1100 637

The stabilizers of the invention are clearly superior to the controls in enhancing resistance of the polyethylene to degradation under ultraviolet light and at elevated temperature.

Acrylonitrile-butadiene-styrene terpolymer resin compositions were prepared using stabilizers of the invention and having the following formulation:

The stabilizer was blended with the resin on a two roll mill, and sheets 2.5 mm thick were prepared by compression molding of the resulting blend. Pieces 2.5 cm square were cut off from the sheets, and subjected to ultraviolet light in a Weather-O-Meter for 800 hours. Tensile strength before and after the test exposure was determined, and the results reported as the percent of tensile strength retained, at the end of this time, in Table V.

Heat stability was evaluated by heating at 210.degree. C under a stress of 50 kg/cm.sup.2 for ten minutes, and then noting color on a scale from 1 to 10 in which 10 is brown and 1 is white. Color is reported in Table V.

It is apparent from the data that the stabilizers of the invention are superior to the controls.

Polyamide resin compositions were prepared using stabilizers of the invention and having the following formulation:

The stabilizer was blended with the finely powdered poly-epsiloncaprolactam in a ball mill for fifteen minutes, and the resulting powder was then compression-molded at 250.degree. C to form sheets 0.5 mm thick. Pieces 2.5 cm square were cut out from the sheets, and exposed to ultraviolet light in a Weather-O-Meter for 120 hours. At the conclusion of the test period, the color of the sheets was noted. The color was also noted after heating at 225.degree. C for 30 minutes in a Geer oven.

It is apparent that the stabilizers of the invention are effective ultraviolet light and heat stabilizers for polyamide resins.

Polybutylene terephthalate resin compositions were prepared having the following compositions:

The compositions were extruded to form pellets, and then test pieces were molded from the pellets by injection molding at 270.degree. C. Test pieces were irradiated with ultraviolet light for 500 hours in a Weather-O-Meter. Other test pieces were heated in an air oven at 150.degree. C for 240 hours to determine heat stability. Tensile strength before and after the test was determined, and the percent tensile strength retained in each test is given in Table VII:

It is apparent that the stabilizers of the invention are effective ultraviolet light and heat stabilizers for polyester resins.