Patent Publication Number: US-4096114-A

Title: 2,2,6,6-Tetramethyl piperidyl-4-phosphites as stabilizers for organic polymeric materials

Description:
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: ##STR1## or a salt thereof. 
     In the above Formula: 
     R 1  and R 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: ##STR2## OR A GROUP OF THE FORMULA ##STR3## n is an integer of 1 to 3 inclusive: and R 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: ##STR4## 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: ##STR5## wherein R 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; 
     wherein n is 1, R 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 ##STR6## in which R 3  represents hydrogen atom, a lower alkyl group or phenyl group and R 4  represents an alkyl group; 
     when n is 2, R 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 2  represents an aromatic triacyl group or a trivalent group from an oxoacid; and 
     when n is 4, R 2  represents an aromatic tetraacyl group, and A represents a group ##STR7## in which R 5  represents hydrogen atom or a lower alkyl group or, when n is 1, R 5  may represent together with R 2  a group ##STR8## in which R 6  represents the same group as defined in R 1  and may be the same or different from R 1 , or a group ##STR9## in which m is 1 or 2 and R 7  represents hydrogen atom or, when n and m are 1, R 7  represents methylene group together with R 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: ##STR10## wherein R&#39; 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 ═N--R&#34; in which R&#34; is hydrogen atom, an alkyl group or a substituted alkyl group; 
     Z represents oxygen atom or a group of the formula &gt;N--R&#39;&#34; 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 ##STR11## 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&#39; 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: ##STR12## 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: ##STR13## 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: ##STR14## wherein R 1  and R 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; 
     R 3  is an alkyl group of from one to twenty atoms; 
     R 4  is hydrogen or methyl, and 
     m is 0 or 1. 
     The substituted piperazinodiones of No. 3,920,659 have the formula: ##STR15## wherein R 1  and R 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 3  is an alkyl group of from one to twenty carbon atoms; 
     when n is 2, R 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. 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: ##STR16## wherein R 1  and R 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 3  is hydrogen, alkyl having one to twelve carbon atoms, β-methoxyethyl, alkenyl having three or four carbon atoms, propargyl, benzyl or alkyl-substituted benzyl; 
     R 4  is straight or branched-chain alkylene having five to eight carbon atoms, or the group (CH 2 ) m  Y(CH 2 ) 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 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: ##STR17## wherein X is S, SO or SO 2  and Y and Y 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 1  are other than O- 
     Randell et al in published U.S. Pat. application Ser. No. B408,123 published Apr. 13, 1976 disclose substituted piperidine-4-ols having the formula: ##STR18## wherein R 1  and R 2  are the same or different and each is a straight- or branched alkyl residue having from one to twelve carbon atoms, or R 1  and R 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: ##STR19## wherein R 1  and R 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 2  X wherein X is the group ##STR20## wherein R 3  is hydrogen, a methyl or phenyl residue, the group ##STR21## wherein R 4  is an alkyl residue having from one to twenty carbon atoms. 
     Cook U.S. Pat. No. 3,929,804 patented Dec. 30, 1975 discloses 4-piperidine acetamide compounds having the formula ##STR22## wherein R 1  and R 2  are the same or different and each is a straight- or branched alkyl residue having from 1 to 12 carbon atoms, or R 1  and R 2 , together with the carbon atom to which they are attached form a cycloalkyl group having from five to twelve carbon atoms; 
     R 3  is hydrogen, a straight- or branched alkyl residue having from one to four carbon atoms, an aralkyl residue having from 7 to 9 carbon atoms or a cycloalkyl group having from five or six carbon atoms; 
     R 4  is a metal ion or a hydrocarbyl residue having from 2 to 20 carbon atoms and being either unsubstituted or substituted by halogen or interrupted by one or more oxygen or sulphur atoms; 
     X is--O--,--S--, or &gt;NR 5 , wherein R 5  has the same significance as R 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 substituent on the piperidyl nitrogen atom, Y being alkyl, alkenyl, aralkyl or a group ##STR23## wherein R 7  is hydrogen, alkyl or phenyl. 
     In accordance with the instant invention, 2,2,6,6-tetramethylpiperidyl-4-phosphites are provided having the formula: ##STR24## R 1  is selected from the group consisting of: ##STR25## R 2 , R 3  and R 4  (and R 5  in Formula IV below) are selected from the group consisting of: ##STR26## hydrogen, alkyl having from one to about twenty carbon atoms; aryl and hydroxyaryl having from 6 to about 20 carbon atoms; alkyl aryl and aryl alkyl having from 7 to about 20 carbon atoms; hydroxyalkyl and hydroxyalkylene oxyalkylene having from 2 to about 30 carbon atoms; and R 1  and R 2  ; taken together to form  R is selected from the group consisting of hydrogen and ##STR27## R 6  is alkyl having from one to about six carbon atoms; Y is selected from the group consisting of hydrogen and oxygen; 
     m is a number selected from 0, 1, 2, 3 and 4; 
     n is a number selected from zero to 20, when n is zero, at least one of R 2  and R 3  being derived from a polyol or a polyphenol. 
     Z is selected from the group consisting of bivalent, trivalent and tetravalent alkylene having from 2 to about 30 carbon atoms; bivalent, trivalent and tetravalent arylene, bis arylene and tris arylene, having from 6 to about 30 carbon atoms; mono, di or tri N-substituted cyanuric acid; and taken with OR, R 1  or R 2  and R 3  or R 4  to form the group: ##STR28## in which Z 1  is selected from the group consisting of ##STR29## 
     In the case where the Z substituent is alkylene, the Z radical is a polyol residue, and the compounds take the form: ##STR30## where: n 1  is a number from 2 to 20; and 
     R 1 , r 2 , r 3 , and n are as in Formula I. 
     When Z is arylene, the radical is polyphenol residue, and the compounds take the form: ##STR31## where: R 0  is alkyl having from one to about twenty carbon atoms; 
     p is a number selected from zero to 4; 
     n 2  is zero or 1; and 
     Y 1  is a bivalent or trivalent linking radical and is selected from the group consisting of alkylene groups having from one to about twenty carbon atoms; oxygen; sulfur; cycloalkylene having from about five to about seven atoms; and arylene having from six to about thirty atoms. 
     R 0  and OH can be in any position or positions of the ring. OH is preferably in the para position to Y 1 . 
     When Z is taken together with OR, R, or R 2  and R 3  or R 4 , the compounds take the form: ##STR32## where R 1 , R 5  and Z 1  are as above. 
     Other variations will be apparent from consideration of Formula I. 
     The R 0 , R 2 , R 3 , R 4 , R 5  and R 6  alkyl 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; n-heptyl; isoheptyl; n-octyl; isooctyl; n-nonyl, n-isononyl, t-nonyl; decyl; undecyl; dodecyl; tridecyl; tetradecyl, hexadecyl, octadecyl, and eicosyl. 
     The R 2 , R 3 , R 4  and R 5  aryl have from six to twenty carbon atoms and include phenyl, napthyl and phenanthryl. 
     The R 2 , R 3 , R 4  and R 5  aralkyl have from seven to about twenty carbon atoms, and include phenmethyl, phenethyl, phenpropyl, phenbutyl, phendecyl, phendodecyl, and naphthethyl, methyl phenyl, dimethyl phenyl, trimethyl phenyl, octyl phenyl, ethyl butyl phenyl, and ethyl phenyl dodecyl phenyl. 
     The R 2  or R 3  or R 4  or R 5  hydroxy aryl can take the form: ##STR33## where Y 1 , R 0 , n 2  and p are as in Formula III. 
     Exemplary Y groups are alkylene, alkylidene, and alkenylene; arylene, alkylarylene, arylalkylene; cycbalkylene, cycloalkylidene, and oxa- and thia-substituted such groups; carbonyl groups, tetrahydrofuranes, esters and triazino groups, The Y groups are usually bi, tri, or tetravalent, connecting two, three or four ##STR34## However, higher valence Y groups, connecting more than four ##STR35## can also be used. According to their constitution, the Y groups can be assigned to subgenera as follows: 
     (1) Y groups where at least one carbon in a chain or cyclic arrangement connect the aromatic groups, such as ##STR36## (2) Y groups where only atoms other than carbon link the aromatic rings, such as ##STR37## and --(S)x-- where X is a number from one to 10; (3) Y groups made up of more than a single atom including both carbon and other atoms linking the aromatic nuclei, such as ##STR38## 
     The following compounds are exemplary: 1  ##STR39## 
     These compounds are readily prepared by conventional transesterification reaction procedures, starting from a simple triphosphite such as triphenylphosphite or trimethyl phosphite and the corresponding polyol, polyphenol, or derivative thereof. Transesterification or organic triphosphites is normally carried out in the presence of an acid or base serving as a catalyst, and the phenol or alcohol liberated in the course of the transesterification is removed by distillation, so as to drive the reaction forward. Thus, the starting triphosphite should be one in which the phenol or alcohol liberated in the course of the transesterification has a lower boiling point at normal or subatmospheric pressure than the alcohol or phenol to be introduced by the transesterification reaction. 
    
    
     The following Examples are illustrative of the preparatory procedure. 
     EXAMPLE I 
     Bisphenol A, 2,2-dimethyl-methylene-bis-phenol, 0.1 mol, 22.8 grams, triphenyl phosphite, 31 grams, 0.1 mol; 9-aza-3-ethyl-3-hydroxymethyl-8,8,10,10-tetramethyl-1,5-dioxaspyro (5.5) undecane, 54.2 g (0.2 mol); and potassium carbonate, 0.1 g, were mixed and reacted under reflux at 130° C for three hours under a nitrogen gas atmosphere. Distillation of phenol then was begun, and continued at 160° C for two hours under reduced pressure. A colorless sticky liquid was obtained, having a phosphorus content of 3.60%, corresponding to the calculated value of 3.63% for the compound of the formula ##STR40## 
     EXAMPLE II 
     Triphenyl phosphite 31 grams (0.1 mol), Bisphenol A 2,2-dimethyl-methylene-bis-phenol, 11.4 grams, (0.05 mol); 9-aza-3-ethyl-3-hydroxymethyl-8,8,10,10-tetramethyl-1,5-dioxaspyrao-(5,5) undecane (0.2 mol) 54.2 grams; and potassium carbonate 0.1 gram were mixed and reacted under reflux at 140° C for three hours under a nitrogen gas atmosphere. Distillation of phenol at 170° C was then begun, under reduced pressure, and continued for 2 hours. The reaction product was a white glassy solid whose melting point was 47°-55° C. The phosphorus content was 3.25%, corresponding to the calculated phosphorus content of 3.20% for the compound of the formula: ##STR41## 
     EXAMPLE III 
     Trimethyl phosphite 12.4 g (0.1 mol), pentaerythritol 6.8 g (0.05 mol), 9-aza-3-hydroxymethyl-8,8,10,10-tetramethyl-1,5-dioxaspyro (5.5) undecane 27.1 g (0.1 mol) and potassium carbonate 0.05 g were mixed and heated under reflux at 110° C while methanol was distilled off. After all of the methanol calculated to be liberated had been distilled, the reaction temperature was brought up to 160° C, and held there for one hour. The reaction product was a glassy solid, melting point 43°-59° C. The phosphorus content was 6.64%, corresponding to the calculated value of 6.70% for the compound of the formula: ##STR42## 
     The 2,2,6,6-tetramethyl-piperidyl-4-phosphites 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, ethylenepentane 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 fatty 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, flame proofing 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. 
     EXAMPLES 1 to 7 
     A group of six polyvinyl chloride resin compositions was prepared having the following formulation: 
     
         ______________________________________                                    
Ingredient            Parts by Weight                                     
______________________________________                                    
Polyvinyl chloride    100                                                 
Dioctylphthalate      50                                                  
Epoxidized soya bean oil                                                  
                      2.0                                                 
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 (reported in Table I as hours to failure) 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 repeated for a total of seven stabilizers in accordance with the invention, having the formulae indicated in Table I. The following results were obtained: 
     
                                           TABLE I                                 
__________________________________________________________________________
                                                          Hours           
Ex.                                                       to              
No.  Stabilizer                                           Failure         
__________________________________________________________________________
Control                                                                   
     2,2,6,6-tetramethylpiperidinyl-4-benzoate            270             
      ##STR43##                                           390             
2                                                                         
      ##STR44##                                           420             
3                                                                         
      ##STR45##                                           420             
4                                                                         
      ##STR46##                                           480             
5                                                                         
      ##STR47##                                           370             
6                                                                         
      ##STR48##                                           460             
7                                                                         
      ##STR49##                                           450             
__________________________________________________________________________
 
    
     It is apparent that each of the seven stabilizers in accordance with the invention is far superior to the control, a conventional ultraviolet light stabilizer for polyvinyl chloride, 2,2,6,6-tetramethyl-piperidyl-4-benzoate. 
     EXAMPLES 8 to 16 
     Polypropylene compositions were prepared, using nine stabilizers of the invention and three of the prior art, and having the following formulation: 
     
         ______________________________________                                    
Ingredient           Parts by Weight                                      
______________________________________                                    
Polypropylene        100                                                  
Distearylthiodipropionate                                                 
                     0.3                                                  
Irganox 1076.sup.1   0.1                                                  
Stabilizer as shown in Table II                                           
                     0.3                                                  
______________________________________                                    
 ##STR50##                                                                
 
    
     The composition was thoroughly blended in a Brabender Plastograph, and the compression-molded to form sheets 0.5 mm thick. Pieces 2.5 cm square were cut off from the sheets and exposed to a carbon are in a Weather-O-Meter for 350 hours. Elongation before and after 350 hours exposure was determined, and the percent of retention of elongation is shown in Table II. 
     
                                           TABLE II                                
__________________________________________________________________________
                                                           %              
                                                           Elong-         
                                                           ation          
Ex.                                                        Re-            
No.  Stablizer                                             tention        
__________________________________________________________________________
Control 1                                                                 
     2(2&#39;-hydroxy-5&#39;-methylphenyl)benzotriazole            17.5           
Control 2                                                                 
     2,2,6,6-tetramethylpiperidinyl-4-benzoate              4.7           
Control 3                                                                 
     bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate         5.3           
      ##STR51##                                            39.5           
9                                                                         
      ##STR52##                                            42.7           
10                                                                        
      ##STR53##                                            43.6           
11                                                                        
      ##STR54##                                            43.2           
12                                                                        
      ##STR55##                                            49.5           
13                                                                        
      ##STR56##                                            41.4           
14                                                                        
      ##STR57##                                            53.2           
15                                                                        
      ##STR58##                                            50.1           
16                                                                        
      ##STR59##                                            52.0           
     (X : t-butyl)                                                        
__________________________________________________________________________
 
    
     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. 
     EXAMPLES 17 to 23 
     Seven ethylene-vinyl acetate copolymer compositions were prepared using six 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° C, and sheets 1 mm thick were then compression molded at 120° 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: 
     
                                           TABLE III                               
__________________________________________________________________________
                                                        % Retention       
Ex.                                                     of Tensile        
No.  Stabilizer                                         Strength          
__________________________________________________________________________
Control                                                                   
     2-hydroxy-4-methoxybenzophenone                    71                
17                                                                        
      ##STR60##                                         85                
18                                                                        
      ##STR61##                                         84                
19                                                                        
      ##STR62##                                         83                
20                                                                        
      ##STR63##                                         80                
21                                                                        
      ##STR64##                                         79                
22                                                                        
      ##STR65##                                         82                
23                                                                        
      ##STR66##                                         80                
__________________________________________________________________________
 
    
     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. 
     EXAMPLES 24 to 31 
     Seven high density polyethylene compositions were prepared using five 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: 
     
                                           TABLE IV                                
__________________________________________________________________________
Ex.                                                       Hours to        
No.  Stabilizer                                           Failure         
__________________________________________________________________________
Control                                                                   
     2,2,6,6-tetramethylpiperidinyl-4-benzoate             730            
24                                                                        
      ##STR67##                                           1350            
25                                                                        
      ##STR68##                                           1420            
26                                                                        
      ##STR69##                                           1400            
27                                                                        
      ##STR70##                                           1450            
28                                                                        
      ##STR71##                                           1320            
29                                                                        
      ##STR72##                                           1430            
30                                                                        
      ##STR73##                                           1460            
31                                                                        
      ##STR74##                                           1420            
__________________________________________________________________________
 
    
     The stabilizers of the invention are clearly superior to the control in enhancing resistance of the polyethylene to degradation under ultraviolet light. 
     EXAMPLES 32 to 37 
     Six acrylonitrile-butadiene-styrene terpolymer resin compositions were prepared using six stabilizers of the invention and compared to one of the prior art, all seven having the following formulation: 
     
         ______________________________________                                    
Ingredient             Parts by Weight                                    
______________________________________                                    
Acrylonitrile-butadiene-styrene terpolymer                                
                       100                                                
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. 
     
                                           TABLE V                                 
__________________________________________________________________________
                                                          % Re-           
                                                          tention         
                                                          of Ten-         
Ex.                                                       sile            
No. Stabilizer                                            Strength        
__________________________________________________________________________
Con-                                                                      
    2-hydroxy-4-octoxybenzophenone                        75              
trol                                                                      
32                                                                        
     ##STR75##                                            88              
33                                                                        
     ##STR76##                                            92              
34                                                                        
     ##STR77##                                            94              
35                                                                        
     ##STR78##                                            91              
36                                                                        
     ##STR79##                                            89              
37                                                                        
     ##STR80##                                            93              
    (X : t-butyl)                                                         
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     The stabilizers of the invention are clearly superior to the control in enhancing resistance of the acrylonitrile-butadiene-styrene terpolymer to degradation under ultraviolet light. 
     EXAMPLES 38 to 44 
     Seven polyamide resin compositions were prepared using seven stabilizers of the invention, all 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° 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 change in color is given in Table VI. 
     
                                           TABLE VI                                
__________________________________________________________________________
Ex.                                                      Change in        
No.                                                                       
   Stabilizer                                            Color            
__________________________________________________________________________
Con-                                                                      
   None                                                  yellow           
trol                                                                      
38                                                                        
    ##STR81##                                            none             
39                                                                        
    ##STR82##                                            none             
40                                                                        
    ##STR83##                                            none             
41                                                                        
    ##STR84##                                            none             
42                                                                        
    ##STR85##                                            none             
43                                                                        
    ##STR86##                                            none             
44                                                                        
    ##STR87##                                            none             
__________________________________________________________________________
 
    
     The stabilizers of the invention are clearly superior to the control in enhancing resistance of the poly-episilon-caprolactam to degradation under ultraviolet light. 
     EXAMPLES 45 to 51 
     Seven rubber-modified polystyrene resin formulations were prepared having the following composition: 
     
         ______________________________________                                    
Ingredient           Parts by Weight                                      
______________________________________                                    
Rubber modified polystyrene                                               
                     100                                                  
Ca-stearate          1.0                                                  
Stabilizer as shown in Table VII                                          
                     0.25                                                 
______________________________________                                    
 
    
     The compositions were extruded to form pellets, and then test pieces were molded from the pellets by injection molding at 230° C. The test pieces were irradiated with ultraviolet light for 320 hours in a Weather-O-Meter. Tensile strength before and after exposure was determined, and the percent tensile strength retained after the exposure is given in Table VII: 
     
                                           TABLE VII                               
__________________________________________________________________________
                                                          %               
                                                          Retention       
                                                          of              
Example                                                   Tensile         
No.  Stabilizer                                           Strength        
__________________________________________________________________________
Control                                                                   
     2-hydroxy-4-octoxybenzophenone                       50.1            
45                                                                        
      ##STR88##                                           73.1            
46                                                                        
      ##STR89##                                           77.2            
47                                                                        
      ##STR90##                                           75.6            
48                                                                        
      ##STR91##                                           70.3            
__________________________________________________________________________