IL44444A - 0,0-bis (aryl)-amidothiophosphates and their use as light stabilizers for polyolefins - Google Patents

Description

44444/2 ,0-BIS (ARYL) AMIDOTHIOPHOSPHATES AND THEIR USE AS LIGHT STABILIZERS FOR POLYOLEPINS 44444/2 This invention relates to stabilizing polyolefins against the deteriorating effects of light by. the use of certain 0,0-bis (aryl) amidothiophosphates, alone or in combina^ tion with a 2-hydroxy-4-alkoxybenzophenone, and to certain novel 0,0-bis(phenyl)amidothiophosphate compounds.

Some of the compounds of this invention are previously known and reported in, for example, the U.S. Patents 2,615,037 and 2,994,638. The compounds in said patents are reported to be effective as insecticides and fungicides as evidenced by testing on certain bugs. Nowhere in said patents is it suggested that these compounds can be used for the stabilization of polymers against light.

As is well Known, polyolefins such as polypropylene and polyethylene tend to deteriorate from the effects of light, especially ultraviolet light.

This deterioration generally manifests itself as a loss of tensile strength and loss of flexibility of the polymer. .

In accordance with the present invention, . we have found that certain 0,0-bis (aryl) amidothiophosphates, alone or in combination with a 2-hydroxy-4-al-koxybenzophenone, can significantly retard or inhibit such deterioration.

The 0,0-bis( aryl )amidothlophosphates useful for the practice of the present invention include those having the formula: S wherein: R is hydrogen, alkyl of 1-12 carbons, or halogen; Ar is phenyl or naphthyl; n is 1 or 2; and R' and R" , which may be the same or different, are hydrogen, alkyl of 1-18 carbons, 2,2,6,6-tetramethyl-iJ--piperidyl, cycloalkyl of 5-6 carbons or both R* and R" , together with the N to which they are attached, form a morph'olino or piperidino ring. Within this class of compounds, those which are preferred since they give better light stability to polyolefins are the compounds of the formula: wherein: R is hydrogen, alkyl of 1-12 carbons, or halogen; R' and R" , which may be the same or different, are hydrogen, cyclohexyl, or 2,2,6,6-tetramethyl-4-piperidyl. Especially preferred, since they give the best light sta-bility to polyolefins, are the novel compounds of the formula : wherein: R is alkyl of 1-6 carbons or halogen; R' is cyclohexyl or 2,2,6,6-tetramethyl-l-piperidyl; and R" ~ is hydrogen or R' .

As a broad class, amidophosphates are known compounds as shown in such references as United States. Patents 3,100,197; 3,309,317; and 3,531,550; British Patents 9^1,575 and 1,039,921; and Kosolapoff, "Organo-phosphorus Compounds" (1950) pages 278-321. Such broad class of amidophosphates may be represented by the formula : wherein: Q, Q', and Q" represent hydrogen or organic moieties, n is 1, '2, or 3, and X is oxygen or sulfur. In accordance with our invention, we have foiind that only a very small segment of this broad class contains compounds useable alone or in combination with a 2-hy-droxy-4-alkoxybenzophenone to stabilize polyolefins against deterioration by light. The compounds of this small segment, having the structural formulae (I), (II), or (III), supra, have certain structural features in common. First, the X of formula (IV) must be sulfur; compounds wherein the X is oxygen are greatly inferior or even inoperative as light stabilizers in polyolefins. Second, n of formula (IV) must be one; the diamides and triamides are greatly inferior as light stabilizers in polyolefins. Third, the Q of formula (IV). should be aromatic and the Q' and Q" should not be aromatic since compounds wherein Q is aliphatic and compounds wherein Q' or Q" is aromatic are inferior for this purpose.

The compounds of formula (IV), supra, can be prepared in several ways, one of which is described generically in United States Patent 3*531,550 (columns 3 and 4). To make the specific compounds of formulae (I), (II), or (III), supra, the appropriate phenol. can be reacted with thiophosphoryl chloride in the presence of an HCl-acceptor or base to give an intermediate which can then be reacted with the appropriate amine to give the desired 0,0-bis( aryl )amidothiophosphate, ac- cording to the following reaction sequence: To make compounds of formulae (I), (II), or (III), supra, suitable monohydroxy-phenols include phenol, methylphenols or cresols, ethylphenols , propylphenols , butylphenols , hexylphenols , octylphenols , nonylphenols , decylphenyls , dodecylphenols , dimethylphenols or xylen- ols, isopropylmethyl-phenol or thymol, dl-tert .butyl- phenols , chlorophenols , methylchlorophenols , naphthols, methylnaphthols , ethylnaphthols , chloronaphthols , etc. Preferably, where the phenol has one substituent, such substituent is in the para position. Suitable amines Include ammonia, methylamine, ethylamine, butylamines, hexylamines, octylamines, dodecylamines , octadecyl- ^ amines, cyclopentylamine, cyclohexylamine , 4-amino- -2,2,6,6-tetramethylpiperidine, morpholine, piperidine, dimethylamine , dibutylamines , dioctylamines , methyl-butylamine, methylcyclohexylamine , dicyclohexylamine , etc .

The compounds of formulae (I), "(II), and (III), supra, when incorporated alone in polyole ins significantly inhibit degradation due to exposure to light.

This effect can be greatly enhanced if a 2-hydroxy-4- -alkoxybenzophenone , a 2- ( 2 '-hydroxyphenyl )benzotriazole , a nitroxide, a tetramethylpiperidine derivative, or a 3 , -ditert .butyl-4-hydroxybenzoate is also incorporated in the polyolefin. Illustrative of such enhancing com- pounds are those mentioned in such prior art as United States Patents 3 ,18 ,615 i 3,206,431; 3,230,194; 3,431,232; 3,431,233; 3,436,369; 3,448,074; 3,474,068; and 3,640,928.

When used alone, or in combination with a 2-hy- droxy-4-alkoxybenzophenone , the 0,0-bis( aryl )amidothio- phosphate is usually incorporated into the polyolefin at a concentration of 0.1 to 2% by weight, preferably at a concentration of 0.2 to 0.5% on weight of polyolefin.

When used with the enhancer, the ratio of the 0,0-bis- (aryl)amidothiophosphate to the 2-hydroxy-4-alkoxybenzo- phenone may be between 10/1 and 1/10, although a ratio of about 1/1 is usually preferred. Further enhancement is oftentimes obtained when the 0 ,0-bis (aryl )amidothio- phosphate or the combination thereof with the 2-hydroxy- -4-alkoxybenzophenone is used with a phosphite, such as cyclic phosphites as disclosed in United States Patent |P 3,205,250, especially distearylpentaerythritol diphosphate ; tris (p-nonylphenyl)phosphite ; alkyl phosphites, such as dioctylphosphite and tridecylphosphite; alkyl aryl phosphites, such as phenyl dldecyl phosphite; aryl o-phenylene phosphites, such as phenyl or ii-methyl-2 , 6-di-t-butylphenyl o-phenylene phosphite, and the like.

Other additives, such as processing antioxidants, secondary stabilizers such as dilauryl- or distearyl-thiodi-propionate, pigments, dyes, flame retardants, lubricants, etc. may also be included in the polyolefin for their usual purposes.

The following examples illustrate the invention.

Example 1 Preparation of 0,0-bis (p-tert .butylphenyl)-N-cyclohexyl- amldpthiophosphate To a solution of cyclohexylamine ( 20 grams, 0 . 2 mole) in 10 milliliters of dlmethylformamlde and 50 milliliters of benzene at 50-60°C. was added dropwise, with stirring, a solution of 0 ,0-bis (p-tert .butylphenyl)-chlorothiophosphate ( 20 grams, 0.05 mole) in 100 milliliters of benzene. The mixture was refluxed for eight hours, cooled, and filtered. The filtrate was evaporated under reduced pressure, and the oil that remained was triturated with cold methanol. The solid which formed was filtered and recrystallized twice from methanol to give 17.6 grams of product, m.p. 107-109°C.

Example 2 Testing in Polypropylene The compound of Example 1 ( 0 . 5ί by weight) was dry blended with a mastermix of unstabilized polypro- ^ pylene (Profax 6401) and 0.2% by weight of a processing antioxidant, 2 ,4 ,6-tritert .butylphenol . The blend was milled for five minutes at 350-370°F. and the milled sample was compression molded into a film 4-5 mils thick at 400°P. The compression molded film, and a control film identically prepared except without the compound of Example 1, were exposed in a Xenon Weather-O-Meter (Atlas) until they failed. The samples were considered as having failed when the carbonyl content in the infrared spectrum reached 0.1%, a generally accepted point of film embrittlement . The test sample lasted 1625 hours .

Example 3 In the manner of Example 1, using the appropriate amines and appropriate 0,0-bis (phenyl Jchlorothio-phosphates, additional compounds were prepared and tested as in Example 2. The compounds and the test results are described below.

Example 3 - dicyclohexylamine reacted with 0,0- -bis (p-tert ,butylphenyl)chlorothiophosphate to yield 0 ,0-bis (p-tert ,butylphenyl)-N ,N-dicyclohexylamidothio-phosphate, m.p. 208-212°C. which, in polypropylene test sample, lasted 1125 hours.

Example 4 - cyclohexylamine reacted with 0,0- -bis (p-methylphenyl)chlorothiophosphate to yield 0,0--bis (p-methylphenyl)-N-cyclohexylamidothiophosphate, a liquid, which, on testing, lasted 925 hours.

Example 5 - cyclohexylamine reacted with 0,0--bis(p-chlorophenyl)chlorothiophosphate to yield 0,0- -bis (p-chlorophenyl)-N-cyclohexylamidothiophosphate , jjp m.p. 65-67°C. which, on testing, lasted 1225 hours.

Example 6 - cyclohexylamine reacted with 0,0--bis(p-tert .octylphenyDchlorothiophosphate to yield 0,0-bis (p-tert .octylphenyl)-N-cyclohexylamidothiophos-phate, m.p. 80-82°C. which, on testing, lasted 725 hours.

Example 7 - cyclohexylamine reacted with 0,0--bis ( 2 ^-di-tert .butylphenyDchlorothlophosphate to yield 0,0-bis ( 2, 4-di-tert .butylphenyl)-N-cyclohexyl-amidothiophosphate, m.p. 167-168°C. which, on testing, lasted 971* hours.

Example 8 - cyclohexylamine reacted with 0,0--bis (phenyl )chlorothiophosphate to yield 0 ,0-bis (phenyl)--N-cyclohexylamidothiophosphate , m.p. 76-77°C. which, on testing, lasted 1035 hours.

Example 9 - -amino-2,2,6,6-tetramethylpiper-idine reacted with 0 ,0-bis (p-tert .butylphenyDchlorothlophosphate to yield 0,0-bis (p-tert .butylphenyD-N--(2,2,6,6 , -tetramethyl-^-piperidy1 )amidothiophosphate , m.p. 131-133°C. which, on testing, lasted 1225 hours.

Example 10 - morpholine reacted with 0,0-bis-(p-tert .butylphenyDchlorothlophosphate to yield 0,0--bis (p-tert .butylphenyl) -N-oxydiethyleneamidothiophos-phate, m.p. 110-112°C. which, on testing, lasted 975 hours.

Example 11 - ammonia reacted with 0,0-bis(p--tert .butylphenyDchlorothlophosphate to yield 0,0-bis-(p-tert .butylphenyDamidothiophosphate, m.p. 128-129°C. which, on testing, lasted 1025 hours.

Example 12 - di-n-butylamine reacted with 0,0- -bis (p-tert .butylphenyDchlorothiophosphate to yield ^ 0 ,0-bi8 (p-tert . butylphenyl ) - ,N-di-n-butylamidothio- phosphate, a liquid, which, on testing lasted 725 hours.

Example 13 - n-butylamine reacted with 0 ,0-bis- (p-tert .butylphenyDchlorothiophosphate to yield 0 ,0- -bis (p-tert .butylphenyl)-N-n-butylamidothiophosphate , m.p. 78-80°C. which, on testing, lasted 975 hours.

Example 1 - tert .butylamine reacted with 0 ,0- -bis (p-tert .butylphenyDchlorothiophosphate to yield 0 ,0-bis (p-tert ,butylphenyl)-N-tert .butylamidothiophos- phate, m.p. 75-77°C. which, on testing, lasted 875 hours.

Example 15 - n-octylamine reacted with 0 ,0-bis- (p-tert .butylphenyDchlorothiophosphate to yield 0 ,0- -bis(p-tert .butylphenyl)-N-n-octylamidothiophosphate, m.p. 33-37°C. which, on testing, lasted 875 hours.

Example 16 Following the procedure of Example 2 , films were prepared containing 0 . 25¾ of the compound of one of the foregoing examples in combination with 0. 25¾ 2-hydroxy-l-octyloxybenzophenone (Cyasorb UV-53D and tested with the results shown in the following table. ■ Compound of Example Hours to Failure 1 2200 3 3000 7 2200 8 2100 10 2100 13 2000 15 2200 For comparison, a control (without either additive) only lasted 500 hours, and a film containing 0.5% of the 2-hydroxy-4-octyloxybenzophenone without any amido thlophosphate only lasted 1700 hours.

Claims (3)

1. A polyolefin composition stabilized againtR the deteriorating effects of light characterized by having Incorporated therein an effective amount of a stabilizer of the formula: wherein: R is hydrogen, alkyl of 1-12 carbons, or halogen; Ar is phenyl or naphthyl; n is 1 or 2; and R' and R" are hydrogen, alkyl of 1-18 carbons, 2,2,6,6-tetra-methyl-^-piperidyl, cycloalkyl of 5-6 carbons, or both, together with the N, form a heterocyclic ring selected from morpholino or piperidino .

2. A composition as defined in Claim 1 wherein said polyolefin is polypropylene or polyethylene.

3. A composition as defined in Claim 1 also having incorporated therein a S-hydroxy-^-alkoxybenzo-phenone in an amount sufficient to enhance the effect of said stabilizer. . A composition as defined in Claims 1 and 3 wherein said 2-hydroxy-4-alkoxybenzophenone is 2-hydroxy--^-octyloxybenzophenone . 5· A composition as defined in Claim 1 wherein said stabilizer is 0 ,0-bis (p-tert .butylphenyl)-N,N-di-cyclohexyla idothiophosphate . 6. A composition as defined in Claim 1 wherein the stabilizer has the formula: wherein: R is hydrogen, alk l of 1-12 carbons, or halo^ gen; and R' and R" are hydrogen, 2,2,6 ,6-tetramethy1—J— -piperidyl, or cyclohexyl. 7. A composition as defined in Claim 6 also having incorporated therein a 2-hydroxy-4-alkoxybenzo-phenone in an amount sufficient to enhance the effect of said stabilizer. 8. A composition as defined in Claim 7 wherein said 2-hydroxy-M-alkoxybenzophenone is 2-hydroxy-M-octyl-oxybenzophenone . 9. A composition as defined in Claim 8 wherein said stabilizer is 0 ,0-bis (p-tert ,butylphenyl)-N-cyclo-hexylamidothiophosphate . 10. A composition as defined in Claims 6 and 7 wherein the 2-hydroxy-J*-alkoxybenzophenone is 2-hy-droxy- -octyloxybenzophenone and the stabilizer is 0,0--bis (p-tert .butylphenyl)-N,N-dicyclohexylamidothiophos-phate. 11. A composition as defined in Claim 7 wherein said stabilizer is 0,0-bis(phenyl)-N-cyclohexylamido-thiophosphate. 12. A composition as defined in Claim 6 wherein said stabilizer is 0,0-bis(p-chlorophenyl)-N-cyclohexyl-? amidothiophosphate . 13· A composition as defined in Claim 6 wherein said stabilizer is 0,0-bis (p-methylphenyD-N-cyclohexyl-amidothiophosphate . 1 . A composition as defined in Claim 6 wherein R is alkyl of 1-6 carbons, or halogen; R' is cyclohexyl or 2,2,6,6-tetramethyl-il-piperidyl; and R" is hydrogen or R ' . compound having the formula wherein: R is alkyl of 1-6 carbons, or halogen; R' is cyclohexyl or 2,2,6,6-tetramethyl-*»-piperidyl; and R" is hydrogen or R'. 16. A compound as defined in Claim 15 wherein R is tert. butyl and R' is cyclohexyl, and R" is hydrogen or cyclohexyl. 17. A compound as defined in Claim 15 wherein R is chlorine, methyl, or tert.butyl, R' is cyclohexyl, and R" is hydrogen. 18. A compound as defined in Claim 15 which is 0,0-bis (p-tert .butylphenyl)-N-(2,2,6,6-tetramethyl--*J-piperidyl)amidothiophosphate . 19. A compound as defined in Claim 15 which is 0 ,0-bis (p-tert .butylphenyl)-N-cyclohexylamidothio-phosphate. 20. A stabilizer composition useful for stabilizing polyolefins against the deteriorating effects of light, comprising, in combination, a 2-hydroxy-ii--alkoxybenzophenone and a compound of the formula: wherein: R is hydrogen, alkyl of 1-12 carbons, or halogen; Ar is phenyl or naphthyl; n is 1 or 2 ; and R' and R" are hydrogen, alkyl of l-l8 carbons, 2,2,6 , 6-tetramethyl-!i-piperidyl , cycloalkyl of 5-6 carbons, or both, together with the N, form a morpholino or a piperidino stabilizer composition as defined Claim 20 , wherein said compound has the formula: wherein: R is hydrogen, alkyl of 1-12 carbons, or halogen; and R* and R" are hydrogen, 2 , 2 , 6 , 6-tetra-methyl- 4-piperidyl, or cyclohexyl. 22 . A stabilizer composition as defined in Claim 21 wherein: R is alkyl of 1-6 carbons or halogen; Rf is cyclohexyl or 2 , 2 , 6 , 6-tetramethyl-14-piperidyl; and R" is hydrogen or R'. 23 . A stabilizer composition as defined in Claim 22 wherein said compound is 0 , 0-bis (p-tertbutyl-phenyl)-N-cyclohexylamldothiophosphate . 2k. A stabilizer composition as defined in Claim 23 wherein said 2-hydroxy-¾-alkoxybenzophenone is 2-hydroxy-^-octyloxybenzophenone . 25 . A stabilizer composition as defined in Claim 20 wherein the ratio of said 2-hydroxy-1J-alkoxy-benzophenone to said compound is between 10/1 and 1/10 . 26 . A stabilizer composition as defined in Claim 20 wherein the 2-hydroxy-^-alkoxybenzophenone is 2-hydroxy-4-octyloxybenzophenone and the stabilizer is 0 , 0-bis (p-tert ,butylphenyl)-N,N-dicyclohexylamidothio-phosphate. S. HOROWITZ & CO. AGENTS FOR APPLICANTS