# Patent

## Title
Stabilizer mixtures

## Abstract

2,2,6,6-TETRAMETHYL-4-PIPERIDYL THIOCARBOXYLATES AND AMINOCARBOXYLATES ARE PROVIDED HAVING THE GENERAL FORMULA: ##STR1## wherein: M.sub.1, M.sub.3, AND M.sub.4 ARE NUMBERS FROM 0 TO 1; and 2,2,6,6-tetramethyl-4-piperidyl; alkylaryl, aralkyl, and hydroxy-substituted such radicals; 20 carbon atoms, and selected from the group consisting of alkylene and cycloalkylene; and amino-substituted such radicals; ##STR2## Z is an organic radical having a valence from 2 to 4 and from one to about twenty carbon atoms, and selected from the group consisting of alkylene, alkylidene, aralkylene, aralkylidene, alkarylene, alkarylidene, heterocycloalkylene, heterocycloalkylidene, cycloalkylene and cycloalkylidene; amino-substituted such radicals and 2,2,6,6-tetramethyl-4-piperidylidene; groups and at least one ##STR3## ATTACHED TO THE Z radical. Synthetic resin compositions also are provided having their resistance to deterioration in the presence of ultraviolet light enhanced by at least one of these compounds.

## Background
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: 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 oxygen 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; 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; 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; group from an oxoacid; and 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.sub.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; in which R" is hydrogen atom, an alkyl group or a substituted alkyl group; atom, an alkyl group or a substituted alkyl group; 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 5 or 6 carbon atoms;

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;

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. 18, 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; .beta.-methoxyethyl, alkenyl having three or four carbon atoms, propargyl, benzyl or alkyl-substituted benzyl; 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; nickel, manganese, calcium, zinc, iron, sodium, cobalt, tin, and dialkyl tin, and 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 dehydropyridinyl 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 April 13, 1976 disclose substituted piperidine-4-ols having the formula: ##STR21## wherein R.sub.1 and R.sub.2 are the same or different and each is a straight- or branched alkyl residue having from 1 to 12 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 5 to 12 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 1 to 20 carbon atoms, an alkenyl or alkynyl residue having from 3 to 20 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 1 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 1 to 12 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; 4 carbon atoms, an aralkyl residue having from seven to nine carbon atoms or a cycloalkyl group having from 5 or 6 carbon atoms; carbon atoms and being either unsubstituted or substituted by halogen or interrupted by one or more oxygen or sulphur atoms; as R.sub.3 ; and formula I.

Cook U.S. Pat. No. 3,939,168 patented Feb. 17, 1976 discloses closely similar compounds having a Y substituent 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 invention, 2,2,6,6-tetramethyl-4-piperidyl thiocarboxylates are provided having the formla: ##STR27## wherein: m.sub.1, m.sub.3, and m.sub.4 are numbers from 0 to 1; and 2,2,6,6-tetramethyl-4-piperidyl; alkylaryl; aralkyl; and hydroxy-substituted such radicals; carbon atoms, and selected from the group consisting of alkylene and cycloalkylene; and amino-substituted such radicals; twenty carbon atoms, and selected from the group consisting of alkylene, alkylidene, aralkylene, aralkylidene, alkarylene, alkarylidene, heterocycloalkylene, heterocycloalkylidene, cycloalkylene and cycloalkylidene; amino-substituted such radicals and 2,2,6,6-tetramethyl-4-piperidylidene; ##STR28## attached to the Z radical.

Synthetic resin compositions also are provided having their resistance to deterioration in the presence of ultraviolet light enhanced by at least one of these compounds.

Also provided in accordance with the invention are 2,2,6,6-tetramethyl-4-piperidyl aminocarboxylates having the formula: ##STR29## wherein: m.sub.1, m.sub.3 and m.sub.4 are numbers from 0 to 1; aralkyl, cycloalkyl, alkaryl, 2,2,6,6-tetramethyl-4-piperidyl, R.sub.1 OOCY.sub.2, phenyl, hydroxy phenyl and ##STR30## R.sub.1 is selected from the group consisting of hydrogen, alkyl, aralkyl, cycloalkyl and 2,2,6,6-tetramethyl-4-piperidyl; cycloalkyl, aryl, alkaryl, aralkyl, and hydroxy-substituted such radicals; carbon atoms; twenty carbon atoms, and selected from the group consisting of alkylene and cycloalkylene; and about 20 carbon atoms, and selected from the group consisting of alkylene, alkylidene, arylene, aralkylene, aralkylidene, alkarylene, alkarylidene, heterocycloalkylene, heterocycloalkylidene, cycloalkylene and cycloalkylidene; there being from one to four nitrogen-containing such groups, and at least one ##STR31## attached to the Z radical.

A preferred class of 2,2,6,6-tetramethyl-4-piperidyl aminocarboxylates are defined by the formula: ##STR32## where R, R.sub.1, Y.sub.1, Y.sub.2, X, m.sub.2, n.sub.1, n.sub.2 and n.sub.3 are as above, in Formula II. >CHCH.sub.2 -- or >CHCH.sub.2 CH.sub.2 --, n.sub.2 is two or three, n.sub.1 is zero or one, and n.sub.3 is zero, one or two, and when n.sub.3 is one or two, R is hydrogen.

Another preferred class of these aminocarboxylates are defined by the formula: ##STR33## where R, R.sub.1, Y.sub.1, Y.sub.2, X, m.sub.2, n.sub.1, n.sub.2 and n.sub.3 and Z are as above, in Formula II.

Synthetic resin compositions also are provided having their resistance to deterioration in the presence of ultraviolet light enhanced by at least one of these compounds.

The thiocarboxylate compounds are readily prepared from the mercaptocarboxylates of 2,2,6,6-tetramethyl-piperidine-4-ol. The corresponding mercaptocarboxylic acid is reacted with 2,2,6,6-tetramethyl-piperidine-4-ol to form the corresponding mercaptocarboxylate ester, and this compound is then attached to the corresponding --Z-- radical by reaction with the free mercapto group of the mercaptocarboxylate.

The following procedure is illustrative:

5.5 g of benzaldehyde was added slowly to a solution of 100 ml of benzene and 23 g of the thioglycolic acid ester of 2,2,6,6-tetramethyl-piperidine-4-ol below 20.degree. C. The mixture was stirred for 1 hour below 25.degree. C., and an additional 2 hours at 60.degree. C.

The solvent was then distilled off, and the resulting residue of sticky material was dissolved in n-hexane, and stored for eight days under refrigeration. White crystals were obtained, having a molecular weight of 552, corresponding to the calculated molecular weight of 551 for the compound: ##STR34##

A mixture was prepared containing 20 g of the maleic acid diester of 2,2,6,6-tetramethyl-piperidine-4-ol, 29 g of lauryl thioglycolate, 20 ml of tertiary butanol, and 2 ml of a 40% methanol solution of trimethylbenzyl quaternary ammonium hydroxide. The mixture was stirred at from 30.degree. to 35.degree. C. for 2 hours, and then at 60.degree. C. for an additional 4 hours.

The butanol and methanol were distilled off, and the resulting colorless viscous liquid was dissolved in a small amount of petroleum ether and stored for 2 days at 5.degree. C. A white powder was obtained. The molecular weight was found to be 655, corresponding to the molecular weight calculated for the compound: ##STR35##

Using the above reaction procedures, the following additional compounds were prepared: ##STR36##

The following Example illustrates the preparation of the amino carboxylate 2,2,6,6-tetramethyl-4-piperidyl compounds:

A mixture was prepared of 23.3 g of trimethyl nitrilo-triacetate, 61 g of 2,2,6,6-tetramethyl-piperidine-4-ol, 200 ml of xylene and 2 ml of a 12.5% methanol solution of sodium methoxide. The mixture was heated at 160.degree. C. for 6 hours. The solvent was then distilled off, and the resulting residue was then dissolved in n-hexane, and cooled under refrigeration until white crystals were obtained. The white crystals were identified as tris-(2,2,6,6-tetramethylpiperidine-4-yl)nitrilotriacetate, melting point 124.degree. to 126.degree. C. All peaks in the compound's infra-red spectrum are consistent with the following structure: ##STR37##

The powder was oxidized with peracetic acid, yielding a yellow powder.

The molecular weight found for this compound was 655, corresponding to a calculated molecular weight of 654 for the compound: ##STR38##

Using the above procedure, the following compounds were prepared: ##STR39##

The 2,2,6,6-tetramethyl-4-piperidyl thiocarboxylic acid esters and amino carboxylic acid esters 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, acrylonitrile-styrene-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.

The stabilizers of the invention can be employed as the sole stabilizer 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; organic triphosphites; organotin compounds; hindered phenols; and epoxy compounds.

With polyolefin resins there can be employed styrene acid salts of polyvalent metals, organic phosphites, 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 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, polyvalent metal salts of the higher fatty acids, and organic phosphites 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: Ingredient           Parts by Weight ______________________________________ Polyvinyl chloride   100 Dioctylphthalate     50 Ca stearate          1.0 Zn stearate          0.1 Stabilizer as shown in Table I 0.1 ______________________________________

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.

This test was carried out for the stabilizers having the formulae indicated in Table I. The following results were obtained: __________________________________________________________________________ Example No. Stabilizer                              Hours to __________________________________________________________________________ Failure Control 2-hydroxy-4-octoxybenzophenone          360 ##STR40##                              820 2 ##STR41##                              910 3 ##STR42##                              870 4 ##STR43##                              760 5 ##STR44##                              830 6 ##STR45##                              880 __________________________________________________________________________

It is apparent that each of the six stabilizers in accordance with the invention is far superior to the control, a conventional ultraviolet light stabilizer for polyvinyl chloride, 2-hydroxy-4-octoxy-benzophenone.

Polypropylene compositions were prepared, seven stabilizers of the invention, and two of the prior art, and having the following formulation: Ingredient           Parts by Weight ______________________________________ Polypropylene        100 Distearylthiodipropionate 0.3 Goodrite 3114 (1,3,5-tris-(3',5'-di-t-butyl 4'-hydroxybenzyl) isocyanurate) 0.1 Stabilizer as shown in Table II 0.3 ______________________________________

The compositions were 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. 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. __________________________________________________________________________ Example No. Stabilizer                            Hours to Failure __________________________________________________________________________ Control Tinuvin-P (2-(2'-hydroxy-5'-methylphenyl) 340 benzotriazole) ##STR46##                            780 8 ##STR47##                            720 9 ##STR48##                            750 10 ##STR49##                            770 11 ##STR50##                            800 12 ##STR51##                            830 13 ##STR52##                            810 __________________________________________________________________________

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 one of the prior art, and having the following formulation: Ingredient           Parts by Weight ______________________________________ Ethylene-vinylacetate copolymer 100 Stabilizer as shown in Table III 0.2 ______________________________________

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. The results are given in Table III as % retention of the initially determined tensile strength: __________________________________________________________________________ % Retention of Tensile Strength Example No. Stabilizer                                   After 500 __________________________________________________________________________ hours Control 2-hydroxy-4-methoxybenzophenone              72 14 ##STR53##                                   78 15 ##STR54##                                   79 16 ##STR55##                                   84 17 ##STR56##                                   83 18 ##STR57##                                   80 19 ##STR58##                                   78 20 ##STR59##                                   85 __________________________________________________________________________

It is apparent from the results that the stabilizer compositions in accordance with the invention are superior to 2-hydroxy-4-methoxybenzophenone in enhancing the resistance of the ethylene-vinyl acetate copolymer to deterioration in the presence of ultraviolet light.

High density polyethylene compositions were prepared, using seven stabilizers of the invention and two of the prior art, and having the following formulation: Ingredient           Parts by Weight ______________________________________ High density polyethylene 100 Stabilizer as shown in Table IV 0.1 ______________________________________

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. 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 IV: __________________________________________________________________________ Example No. Stabilizer                                   Hours to __________________________________________________________________________ Failure Control A 2-hydroxy-4-methoxybenzophenone               540 Control B Tinuvin-P (2-(2'-hydroxy-5'-methylphenyl)     610 benzotriazole) 21 ##STR60##                                   1030 22 ##STR61##                                   1100 23 ##STR62##                                    980 24 ##STR63##                                    950 25 ##STR64##                                   1080 26 ##STR65##                                   1120 27 ##STR66##                                   1060 __________________________________________________________________________

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

Acrylonitrile-butadiene-styrene terpolymer resin compositions were prepared using seven stabilizers of the invention and one of the prior art, and having the following formulation: Ingredient           Parts by Weight ______________________________________ Acrylonitrile-butadiene- 100 styrene terpolymer Stabilizer as shown in Table V 0.1 ______________________________________

The stabilizer was blended with the resin on a two-roll mill, and sheets 3 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. __________________________________________________________________________ % Tensile Strength Example No. Stabilizer                      Retained __________________________________________________________________________ Control 2,2'-dihydroxy-4-methoxybenzophenone 70 28 ##STR67##                      86 29 ##STR68##                      91 30 ##STR69##                      90 31 ##STR70##                      92 32 ##STR71##                      93 33 ##STR72##                      92 34 ##STR73##                      91 __________________________________________________________________________

It is apparent from the data that the stabilizers of the invention are superior to the 2,2'-dihydroxy-4-methoxybenzophenone of the prior art.

Polyamide resin compositions were prepared using seven stabilizers of the invention and having the following formulation: Ingredient           Parts by Weight ______________________________________ Poly-epsilon-caprolactam 100 Stabilizer as shown in Table VI 0.1 ______________________________________

The stabilizer was blended with the finely powdered polyepsilon-caprolactam 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 results are given in Table VI. __________________________________________________________________________ Example No. Stabilizer                         Color of Sheet __________________________________________________________________________ Control None                               Yellow 35 ##STR74## 36 ##STR75##                         Pale Yellow 37 ##STR76##                         None 38 ##STR77##                         None 39 ##STR78##                         None 40 ##STR79##                         None 41 ##STR80##                         None __________________________________________________________________________

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

A group of polyvinyl chloride resin compositions was prepared having the following formulation: Ingredient           Parts by Weight ______________________________________ Polyvinyl chloride   100 Dioctylphthalate     50 Ca stearate          1.0 Zn stearate          0.1 Stabilizer as shown in Table I 0.1 ______________________________________

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.

This test was carried out for the stabilizers having the formulae indicated in Table VII. The following results were obtained: __________________________________________________________________________ Example No. Stabilizer                Hours to Failure __________________________________________________________________________ Control 2-hydroxy-4-octoxybenzophenone 360 42 ##STR81##                650 43 ##STR82##                800 44 ##STR83##                780 45 ##STR84##                840 __________________________________________________________________________

It is apparent that each of the stabilizers in accordance with the invention is far superior to the control, a conventional ultraviolet light stabilizer for polyvinyl chloride, 2-hydroxy-4-octoxybenzophenone.

Polypropylene compositions were prepared using stabilizers of the invention and of the prior art, having the following formulation: Ingredient           Parts by Weight ______________________________________ Polypropylene        100 Distearylthiodipropionate 0.3 Goodrite 3114 (1,3,5-tris-(3',5'-di-t-butyl 0.1 4'-hydroxybenzyl) isocyanurate) Stabilizer as shown in Table VIII 0.3 ______________________________________

The compositions were 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. 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 VIII. __________________________________________________________________________ Example                                                  Hours No.  Stabilizer                                          to __________________________________________________________________________ Failure Control Tinuvin-P (2-(2'-hydroxy-5'-                        340 methylphenyl)benzotriazole) 46 ##STR85##                                          760 47 ##STR86##                                          800 48 ##STR87##                                          740 49 ##STR88##                                          760 __________________________________________________________________________

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 one of the prior art, and having the following formulation: Ingredient             Parts by Weight ______________________________________ Ethylene-vinylacetate copolymer 100 Stabilizer as shown in Table IX 0.2 ______________________________________

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. The results are given in Table IX as % retention of the initially determined tensile strength: __________________________________________________________________________ % Retention of Example                                    Tensile Strength No.  Stabilizer                            After 500 hours __________________________________________________________________________ Control 2-hydroxy-4-methoxybenzophenone       72 50 ##STR89##                            81 51 ##STR90##                            80 52 ##STR91##                            77 53 ##STR92##                            81 54 ##STR93##                            82 __________________________________________________________________________

It is apparent from the results that the stabilizer compositions in accordance with the invention are superior to 2-hydroxy-4-methoxybenzophenone in enhancing the resistance of the ethylene-vinyl acetate copolymer to deterioration in the presence of ultraviolet light.

High density polyethylene compositions were prepared using stabilizers of the invention and of the prior art, and having the following formulation: Ingredient            Parts by Weight ______________________________________ High density polyethylene 100 Stabilizer as shown in Table X 0.1 ______________________________________

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. 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 X: __________________________________________________________________________ Example No. Stabilizer                            Hours to Failure __________________________________________________________________________ Control A 2-hydroxy-4-methoxybenzophenone        540 Control B Tinuvin-P(2-(2'-hydroxy-5'- methylphenyl)benzotriazole)            610 55 ##STR94##                            1050 56 ##STR95##                            1150 57 ##STR96##                            1090 __________________________________________________________________________

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

Acrylonitrile-butadiene-styrene terpolymer resin compositions were prepared using stabilizers of the invention and of the prior art, and having the following formulation: Ingredient              Parts by Weight ______________________________________ Acrylonitrile-butadiene-styrene terpolymer 100 Stabilizer as shown in Table XI 0.1 ______________________________________

The stabilizer was blended with the resin on a two-roll mill, and sheets 3 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 XI. __________________________________________________________________________ % Tensile Strength Ex. No. Stabilizer                                        Retained __________________________________________________________________________ Control 2,2'-dihydroxy-4-methoxybenzophenone              70 58 ##STR97##                                        87 59 ##STR98##                                        87 60 ##STR99##                                        90 61 ##STR100##                                       91 __________________________________________________________________________

It is apparent from the data that the stabilizers of the invention are superior to the 2,2'-dihydroxy-4-methoxybenzophenone of the prior art.

Polyamide resin compositions were prepared using stabilizers of the invention and having the following formulation: Ingredient            Parts by Weight ______________________________________ Poly-epsilon-caprolactam 100 Stabilizer as shown in Table XII 0.1 ______________________________________

The stabilizer was blended with the finely powdered poly-epsilon-caprolactan 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 results are given in Table XII: __________________________________________________________________________ Example No. Stabilizer                            Color of Sheet __________________________________________________________________________ Control None                                  Yellow 62 ##STR101##                           Pale Yellow 63 ##STR102##                           None __________________________________________________________________________

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

Polypropylene was compounded on the mill with the additives shown in the Table below, and dumbell specimens 0.5 mm thick prepared by injection molding from the milled sheets. Percent elongation was determined on molded samples either as made or after 305 hours Weather-O-Meter exposure. Ingredient            Parts by Weight ______________________________________ Polypropylene (Profax 6501) 100 n-Octadecyl-beta-(4-hydroxy-3,5-di-t- 0.1 butylphenyl)propionate Dilauryl thiodipropionate 0.3 Stabilizer listed in Table XIII 0.1 ______________________________________

The measured elongations before and after Weather-O-Meter exposure for 305 hours are tabulated in Table XIII: ______________________________________ % %        Elong- Elong-   ation Ex.                        ation    after 305 No.     Stabilizer         Initial  hours ______________________________________ None               344      4.4 Control 2,2,6,6-tetramethyl- 193      3.3 A       piperidine- 4-yl benzoate Control Bis (2,2,6,6-tetramethyl- 308      3.9 B       piperidine- 4-yl)sebacate Control 2,2'-thiobis (p-t-octylphenol) C       n-butylamine nickel complex 326      8.2 64      Tetrakis (2,2,6,6-tetramethyl- 297      18.3 piperidine-4-yl) thiodisuccinate (compound No. 34) ______________________________________

The differences in initial elongation are not significant since elongation is very sensitive to imperfections in the samples.

The nickel compound stabilized control C is green, while the other are colorless. The elongation results show that the two piperidinyl esters are essentially without beneficial effect, the nickel complex has a modest beneficial effect, for which the green color must be accepted, and the thiodisuccinate ester of the invention is both more effective than the nickel complex and free of the objectionable color contribution.

Rectangular polypropylene samples 0.5 mm thick were irradicated with a mercury lamp with an output of radiation of 280 mm and higher wave lengths until they became brittle. The formulation was the same as in the preceding experiment except for the use of 0.3 part of stabilizer. The results were as follows: ______________________________________ Ex.                          Hours to No.     Stabilizer           Embrittlement ______________________________________ None                 72 Control Bis(2,2,6,6-tetramethylpiperidine- 216 A       4-yl)sebacate 65      tris(2,2,6,6-tetramethylpiperidine- 425 4-yl)nitrilotriacetate ______________________________________

The superiority of Example 65 is clear.

Polypropylene was compounded with a conventional heat stabilizer combination and variable light stabilizer by mixing on the mill and compression molding 0.5 mm thick panels 15 cm square at 210.degree. C. for 6 minutes. Initial color was rated visually. 15 cm .times. 3 cm strips cut from the panels were exposed to light from a bank of fluorescent lamps 15 cm above the samples until failure by embrittlement.

The base formula was: ______________________________________ Ingredient              Parts by Weight ______________________________________ Polypropylene (Profax 6501) 100 Tris (3,5-di-t-butyl-4-hydroxybenzyl) 0.15 isocyanurate Distearyl thiodipropionate 0.3 Stabilizer listed in Table XVI 0.5 ______________________________________

Initial color, time to embrittlement in the Weather-O-Meter and heat stability, i.e. time to failure in a 150.degree. air oven, are tabulated in Table XVI for each sample. ______________________________________ Hours to Hours to failure Em- Light           Initial  at     brittle- Ex.   Stabilizer      Color    150.degree. C. ment ______________________________________ None            Color-   3850    370 less Con-  2-hydroxy-4-n-octyl- Slightly 3140   1900 trol  oxybenzophenone 0.5 Yellow 66    2-hydroxy-4-n-octyl- oxybenzophenone 0.3 Tris (2,2,6,6-tetra- Color-   4075   2175 methylpiperidine 4-yl) less nitrilotriacetate 0.2 ______________________________________

These results show that with the conventional benzophenone type light stabilizer the beneficial effect on light stability is compensated by a sacrifice in early color and heat stability. With the inclusion of the amino acid ester of this invention in the combination, initial color and heat stability are at least as good as in the control and outstanding light stability is achieved.

## Claims

inventive and patentable embodiments thereof:

1. A 2,2,6,6-tetramethyl-4-piperidyl thiocarboxylates are provided having the general formula: ##STR103## wherein: m.sub.1, m.sub.3, and m.sub.4 are numbers from 0 to 1; and 2,2,6,6-tetramethyl-4-piperidyl; alkaryl, aralkyl, and hydroxy-substituted such radicals; twenty carbon atoms, and selected from the group consisting of alkylene and cycloalkylene; and amino-substituted such radicals; twenty carbon atoms, and selected from the group consisting of alkylene, alkylidene, aralkylene, aralkylidene, alkarylene, alkarylidene, heterocycloalkylene, heterocycloalkylidene, cycloalkylene and cycloalkylidene; amino-substituted such radicals and 2,2,6,6-tetramethyl-4-piperidylidene; ##STR104## attached to the Z radical.

2. A compound according to claim 1 in which n.sub.1 and n.sub.3 are each zero, and n.sub.2 is from 2 to 3.

3. A compound according to claim 1 in which n.sub.1 and n.sub.2 are each one or two, and n.sub.3 is zero.

4. A compound according to claim 1 in which n.sub.2 and n.sub.3 are each one or two, and n.sub.1 is zero.

5. A compound according to claim 1 in which X is hydrogen.

6. A compound according to claim 1 in which X is O.sup...

7. A compound according to claim 1 in which Y.sub.1 and Y.sub.2 are each alkylene.

8. A compound according to claim 1 in which Y.sub.1 and Y.sub.2 are each cycloalkylene.

9. A compound according to claim 1 in which Z is alkylene.

10. A compound according to claim 1 in which Z is alkylidene.

11. A compound according to claim 1 in which Z is phenylalkylidene.

12. A compound according to claim 1 in which there is one sulfur-containing such radical.

13. A compound according to claim 1 in which there are two sulfur-containing such radicals.

14. A compound according to claim 1 in which there are three sulfur-containing such radicals.

15. A compound according to claim 1 in which n.sub.1 and n.sub.2 are each one or two, n.sub.3 is zero, Y.sub.1 and Y.sub.2 are each alkylene, Z is alkylene, and m.sub.4 is one.

16. A compound according to claim 1 in which n.sub.1 and n.sub.3 are each zero, n.sub.2 is one to three, Z is alkylene and Y.sub.2 is alkylene, and m.sub.4 is one.

17. A compound according to claim 1 having the formula: ##STR105##

18. A compound according to claim 1 having the formula: ##STR106##

19. A polyvinyl chloride resin composition having improved resistance to deterioration when heated at 350.degree. F, comprising a polyvinyl chloride resin formed at least in part of the recurring group ##STR107## and having a chlorine content in excess of 40 percent, where X is either hydrogen or chlorine; and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 1.

20. A polyvinyl chloride resin composition in accordance with claim 19, in which the polyvinyl chloride resin is polyvinyl chloride homopolymer.

21. A polyvinyl chloride resin composition in accordance with claim 19, in which the polyvinyl chloride resin is a copolymer of vinyl chloride and vinyl acetate.

22. An olefin polymer composition having improved resistance to deterioration comprising an olefin polymer selected from the group consisting of polymers of alpha-olefins having from two to six carbon atoms and polystyrene, and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 1.

23. An olefin polymer composition in accordance with claim 22 wherein the polyolefin is polypropylene.

24. An olefin polymer composition in accordance with claim 22 wherein the polyolefin is polyethylene.

25. An acrylonitrile-butadiene-styrene polymer having improved resistance to deterioration when heated at 300.degree. F and above and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 1.

26. A synthetic rubbery diene polymer composition having improved resistance to deterioration comprising a rubbery diene polymer and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 1.

27. A polyamide resin composition having improved resistance to deterioration comprising a polyamide resin and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 1.

28. An ethylene-vinyl acetate copolymer composition having improved resistance to deterioration comprising an ethylene-vinyl acetate copolymer and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 1.

29. A 2,2,6,6-tetramethyl-4-piperidyl aminocarboxylate having the formula: ##STR108## wherein: m.sub.1, m.sub.3 and m.sub.4 are numbers from 0 to 1; aralkyl, cycloalkyl, alkaryl, 2,2,6,6-tetramethyl-4-piperidyl, R.sub.1 OOCY.sub.2, phenyl, hydroxy phenyl and ##STR109## R.sub.1 is selected from the group consisting of hydrogen, alkyl, aralkyl, cycloalkyl and 2,2,6,6-tetramethyl-4-piperidyl; cycloalkyl, aryl, alkaryl, aralkyl, and hydroxy-substituted such radicals; twenty carbon atoms; twenty carbon atoms, and selected from the group consisting of alkylene and cycloalkylene; and about twenty carbon atoms, and selected from the group consisting of alkylene, alkylidene, arylene, aralkylene, aralkylidene, alkarylene, alkarylidene, heterocycloalkylene, heterocycloalkylidene, cycloalkylene and cycloalkylidene; one ##STR110## attached to the Z radical.

30. A compound according to claim 29 in which n.sub.1 and n.sub.3 are each zero, and n.sub.2 is from 2 to 3.

31. A compound according to claim 29, in which n.sub.1 and n.sub.2 are each one or two, and n.sub.3 is zero.

32. A compound according to claim 29 in which n.sub.2 and n.sub.3 are each one or two, and n.sub.1 is zero.

33. A compound according to claim 29 in which X is hydrogen.

34. A compound according to claim 29 in which X is O.sup...

35. A compound according to claim 29 in which Y.sub.1 and Y.sub.2 are each alkylene.

36. A compound according to claim 1 in which Z is alkylene.

37. A compound according to claim 29 in which Z is alkylidene.

38. A compound according to claim 29 in which there is one nitrogen-containing such radical.

39. A compound according to claim 29 in which there are two nitrogen-containing such radicals.

40. A compound according to claim 29 in which there are three nitrogen-containing such radicals.

41. A compound according to claim 29 having the formula: ##STR111##

42. A compound according to claim 29 having the formula: ##STR112##

43. A compound according to claim 29 having the formula: ##STR113##

44. A compound according to claim 29 having the formula: ##STR114##

45. A compound according to claim 29 having the formula: ##STR115##

46. A compound according to claim 29 having the formula: ##STR116##

47. A polyvinyl chloride resin composition having improved resistance to deterioration when heated at 350.degree. F, comprising a polyvinyl chloride resin formed at least in part of the recurring group ##STR117## and having a chlorine content in excess of 40 percent, where X is either hydrogen or chlorine; and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 29.

48. A polyvinyl chloride resin composition in accordance with claim 47, in which the polyvinyl chloride resin is polyvinyl chloride homopolymer.

49. A polyvinyl chloride resin composition in accordance with claim 47, in which the polyvinyl chloride resin is a copolymer of vinyl chloride and vinyl acetate.

50. An olefin polymer composition having improved resistance to deterioration comprising an olefin polymer selected from the group consisting of polymers of alpha-olefins having from 2 to 6 carbon atoms and polystyrene, and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 29.

51. An olefin polymer composition in accordance with claim 50 wherein the polyolefin is polypropylene.

52. An olefin polymer composition in accordance with claim 50 wherein the polyolefin is polyethylene.

53. An acrylonitrile-butadiene-styrene polymer having improved resistance to deterioration when heated at 300.degree. F and above and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 29.

54. A synthetic rubbery diene polymer composition having improved resistance to deterioration comprising a rubbery diene polymer and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 29.

55. A polyamide resin composition having improved resistance to deterioration comprising a polyamide resin and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 29.

56. An ethylene-vinyl acetate copolymer composition having improved resistance to deterioration comprising an ethylene-vinyl acetate copolymer and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 29.

57. A polyvinyl chloride resin composition having improved resistance to deterioration when heated at 350.degree. F, comprising a polyvinyl chloride resin formed at least in part of the recurring group ##STR118## and having a chlorine content in excess of 40 percent, where X is either hydrogen or chlorine; and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 41.

58. A polyvinyl chloride resin composition having improved resistance to deterioration when heated at 350.degree. F, comprising a polyvinyl chloride resin formed at least in part of the recurring group ##STR119## and having a chlorine content in excess of 40 percent, where X is either hydrogen or chlorine; and an amount to improve resistance to deterioration of the resin of a compound in accordance with claim 42.