METHOD FOR PREPARING POLYMER BOUND STABILIZERS MADE FROM NON-HOMOPOLYMERIZABLE STABILIZERS

Abstract: A method of preparing a polymer bound stabilizer comprises reacting a stabilizer precursor molecule containing a reactive double bond which is not readily homopolymerizable with a preformed polymer in the presence of a free radical. The stabilizer precursor may be, for example, a hindered piperidine, a hindered phenol antioxidant or a hindered arylamine antioxidant and the polymer may be a polyolefin, polystyrene, polyvinyl chloride, polyamide or an acrylonitrile butadiene styrene polymer, for example.

Description: METHOD FOR PREPARING POLYMER BOUND STABILIZERS MADE FROM NON-HOMOPOLYMERIZABLE STABILIZERS The present invention relates to a method for preparing polymer bound stabilizers. More particularly, the present invention relates to a method for preparing polymer bound stabilizers made from stabilizer molecules which are not readily homopolymerizable. It has long been known that synthetic polymers, especially thermoplastic polymers, are sensitive to a wide variety of degradative processes which may be initiated by exposure to, for instance, ultraviolet radiation and thermal oxidation. This deficiency must be overcome in order for these polymers to find their widest practical application, and a substantial body of art has developed over the years directed to compositions and processes for stabilizing these polymers. The most commonly employed method for stabilizing polymers has been to incorporate an appropriate additive compound (of which there is a wide variety) nto the polymer composition, singly or in various combinations, for the purpose of protecting the polymer structure. Traditionally, most of these stabilizing compounds have been non-polymeric, relatively low molecular weight compounds so that volatility and marginal compatibility of these compounds with the base polymer may cause loss of the additives by way of migration, leaching and similar processes, with a concomitant deterioration in stability. More recently, an approach has been suggested to overcome certain of the known problems of leaching, volatility and marginal compatibility of traditional stabilizers where in the stabilizer molecule is chemically bounded to a polymer. Thus, as disclosed, for instance, in U.S. Patent Number 4,354,007 to Scott (herein the "007 patent) a wide variety of antioxidant and stabilizer molecules may be reacted with pre-formed polymers in the presence of free radicals to provide a stabilized polymer which may be used directly to make a final product or which may be used as a "masterbatch" which may be mixed with further amounts of a suitable, compatible base polymer to provide a stabilized polymer product suitable for wide variety of end use applications. The'007 patent describes a wide variety of antioxidant and stabilizer molecules including compounds selected from categories which include chain-breaking or peroxide-decomposing antioxidants, ultraviolet screening agents, triplet quenchers and metal deactivators. In terms of a limitation on the scope of the stabilizer compounds that may be used, perhaps the most significant structural limitation is that it should be one that "gives rise to a free radical in the molecule" (see col.l, lines 40-50) . In this regard, however, it has been found with regard to the unsaturated or vinyl group containing stabilizer compounds described in the '007 patent and also as to similar stabilizer compounds which have been suggested by others for grafting to pre-formed polymers in the presence of free radicals, that frequently the reactivity of the stabilizer molecules containing polymerizable groups may be such that the stabilizer may tend to homopolymerize with itself to form a polymer or oligomer. Such an oligomer may, of course, have increased molecular weight as compared to the individual stabilizer molecule and this increased weight may inhibit undesired volatilization, and/or migration of the stabilizer in the polymer composition. The oligomeric species may even become bound or grafted to the polymer in which form it will again, of course, offer certain advantages, especially resistance to migration and volatilization. Unfortunately, however, homopolymerization or oligomerization of the stabilizer molecule may generally result in decreased activity of the stabilizer " molecule in the polymer stystem. Thus these materials, especially when the stabilizer activity is measured in a newly formed polymer composition, may show overall lower stabilization activity as compared to a polymer system containing comparable levels of non-polymerized individually grafted stabilizer molecules. While these homopolymerizable or oligomer forming stabilizer species may out-perform the conventionally, stabilized polymers over the long term or after the polymers have been subjected to severe conditions, it would be highly desirable to provide a polymer system which has been stabilized with molecules that tend not to preferentially polymerize themselves or graft with a preformed polymer in the presence of a free radical. By so doing the typically high levels of initial stabilization activity which may characterize certain of the traditional "non-bound' stabilizers may be achieved while also avoiding or minimizing many of the problems associated with such traditional stabilizers such as migration, leaching and similar processes. Accordingly, the present invention provides a method for preparing a polymer bound stabilizer which comprises reacting a stabilizer precursor molecule containing a reactive double bond which is not readily homopolymerizable with a pre-formed polymer in the presence of a free radical. According to a preferred embodiment, the stabilizer precursor molecules which may be used according to the process include those selected from A-X ' X ' -A' in which: X and X' independently selected from oxygen or nitrogen; Y and Z are independently selected from H, C--C ιa alkyl groups, or o ) ) —C-X-A" in which X is as defined above, and A is selected from a chain breaking antioxidant functionality, a peroxide decomposer functionality, an ultraviolet light screening functionality, a metal deactivator functionality or a triplet quencher functionality; and A* and A" are independently selected from A, Y or Z. The structure of the stabilizer precursor molecules, according to the invention may be described as containing essentially two components, a linking or bonding component (that is the portion of the molecule which provides the reactive double bond) and an active stabilizer functionality-providing component. As long as an individual stabilizer precursor molecule contains both components a wide variety of specific structures may be envisioned. As may be understood by reference to the following structural formulas, preferential linking or bonding components may be represented by the following: 0 0 II II -OC- -CH =CH-C0-A 0 0 II II A-OC- CH= =CH-CO-A . 0 0 II II R-OC- CH= •CH-CN-A 1 '• R l 0 0 II II . A-NC- CH= CH-CN-A ' CH-CO-A ' 0 0 II CHCO-A in which R and R, are independently selected from hydrogen, or an alkyl group containing from 1 to about 18 carbon atoms . In the above formulae which represents the preferred linking or bonding component of the stabilizer precursor molecule, the descriptions A and optionally A' represent the stabilizer functionality components. The various categories of stabilizer functionalities may be represented by the following formulae: 1) Chain breaking antioxidants, including hindered phenols, hindered piperidines, and arylamine antioxidants : in which n is an integer from 1 to about 6, and R_ and R 3 are independently seleted from methyl, t-butyl, or phenyl; or in which R. is hydrogen, oxygen, or an alkyl or aryl group containing from 1 to about 8 carbon atoms; or j Qne i 2) Peroxide decomposing antioxidants : ■ ( CH 2 ) n , S 5 in which n' is an integer from 1 to about 18 and R g is hydrogen or an alkyl group containing from 1 to about 18 carbon atoms, 3) Ultraviolet light screening agents, including benzophenone and benzothiazole UV absorbers: in which R g and R_ are independently selected from hydrogen, methyl, or ethyl and n" is an integer from 1 to about 10. 4) Triplet quenchers peroxide decomposers, including nickel and zinc chelates: •CH 2 CH 2 -C // M C-N ι -CH 2 CH 2 - in which R g is hydrogen or an alkyl or arly group containing from 1 to about 10 carbon atoms, and M is Ni or Zn. 5) Metal deactivators, including hydrazides: H H in which R g is defined above. Preferred hindered piperidine stabilizers of the present invention include: where R q is hydrogen or a lower alkyl group containing up to 8 carbon atoms. The hindered phenols of the present inventions include 2,6-dialkl or diaryl substituted phenols in which at least one alkyl or aralkyl group is tertiary. Preferred hindered phenols of the present inventions include: H0 - "{CH2) » "0CCH"CHC0' 0 0 II II HO- QV ( C H 2 ) n . NC C H - CHC - ( C H 2 ) m - 0) OH where m is 1 to 6 and R g is defined above. Preferred arylamine antioxidants of the present invention include and Preferred ultraviolet light absorbing stablizers of the present invention include: and. where n = 1 to 6 and R g is defined above. Preferred peroxide decomposing antioxidants of the present invention include: .0 0 R_S(CH 2 ) n ,0CCH=CHC0(CH 2 ) n ,SR 5 and 0 0 R..S( CH,) .0CCH- » CHC0R s a Z n 5 where n* = 1 to 18 and R ς is defined above. Preferred metal deactivating stabilizers of the present invention include: 0 OH HO I! ' II! Ill R-OCCH-CHCN-NCRς and OH HO OH HO III 111 H I III R_CN-NCCH=CHCN-NCR, where R- 3 is defined above. Any of a wide variety of polymers may be used in the process of the present invention. Those polymers which contain carbon, hydrogen, oxygen and/or nitrogen may be preferred. Examples include thermoplastic polymers such as polyolefins homopolymers and copolymers, rubber modified polyolefins, polystyrene, rubber modified polystyrene, polyvinylchloride, polyamides, polyesters, acrylonitrile- butadiene-styrene. Of course mixtures or blends of polymers may be used. The polymers will normally have a high molecular weight so that they are suitable for film or fibre forming purposes, although low molecular weight polymers and even liquid polymers may be used especially when the adducts are to be used as additives for other polymers. It has been found that it is no.t necessary for the polymer to contain unsaturated groups, although polymer substrates having up t about 15 percent unsaturation may be used. In the case of masterbatch, it is particularly convenient to use essential saturated polymers to form a masterbatch concentrate of pol bound antioxidants or stabilizers and in this case, it is normally preferred to restrict the unsaturation in the masterbatch polymer substrate to less than 15% in order not sensitize the polymer to oxidation when the masterbatch is subsequently added to it. Any of a wide range of antioxidant or stabilizer compou may be used according to the process. It may function in t of its stabilizing effect on the polymer system in a wide variety of ways. Thus, for example, the stabilizer may be chain breaking or peroxide decomposing antioxidant, an ultraviolet screening agent, a triplet quencher or a metal deactivator. One skilled in the art will recognize that th terms have a definite meaning, for further details, refere may be made to "Atmospheric Oxidation and Antioxidants" by Scott, Elsevier, 1965, in particular Chapters 4 and 5 as we as "Polymer Stabilization," Ed. W. Lincoln Hawkins, Wiley-Interscience, 1972. The stabilizer compounds of the present invention are to be distinguished from agents such a hydrogen, chlorine or even simple thiols which merely react with a polymer to remove sites of potential oxidative attack e.g., ethylenic double-bonds. Antioxidants in the sense in which this term is understood in the art and in which it is used herein act by interfering with the free radical auto- oxidation process by which a polymer is oxidatively degraded for example, by removing the chain propagating radicals involved or by direct reaction with radical generators, nota hydroperoxides, which initiate the autooxidation process. As with the conventional antioxidants and stabilizers, m than one of the above-mentioned compounds may be used to produce a synergistic effect. The process is particularly suitable for reacting anti- oxidants with polymers during melt processing or mastication Under these conditions, the addition of a radical generator often beneficial. Examples of suitable radical generators include peroxides, such as dicumyl peroxide and 2,5-dimethyl-2,5-di(-t-butylperoxy)hexane, azo compounds, su as azo bis isobutyronitrile (AIBN), or redox systems, such a hydroperoxide and a polyamine or persulfate and a reducing agent. Alternatively, generation of free radicals can be effect mechanochemically by mastication of the polymer, as in an extruder or internal mixer, or with actinic radiation such a ultraviolet light or gamma-radiation. Ultraviolet light initiated reactions are preferably catalyzed with photoactivators which may lead to hydrogen abstraction via a energetic species. In the case where a photosensitizer is used, the optimum ratio of antioxidant to photosensitizer depends upon the polymer, the antioxidant and the photosensitizer, but normally in the range of 20:1 to 0.5:1. The range 10:1 to 1:1 is preferred. The preferred methods for generating free radicals in th polymer are by the addition of an initiator or by masticatio at a temperature appropriate for the polymer system. Where a generator is required, it will be appreciated th such generator should be suitable such that it is dissociate substantially completely at the end of the reaction since otherwise residual generator may react with the subsequent polymer undesirably. For example, residual generator may crosslink the polymer when it is not desired. In other word the generator is added to promote formation of the bound stabilizer and when this function is fulfilled, it should no affect the polymer further. It may also be possible to carry out the grafting reacti in two stages. The first stage may involve building hydro- peroxides into the polymer, for example by prior oxidation, followed by using the hydroperoxide as a built in grafting initiator in the presence of UV light or a reducing agent. In general it may be advantageous to exclude oxygen fr the reactions described above; however, in the case of som ethylenically unsaturated compounds it has been found that presence of oxygen in small amounts, for example oxygen pr as impurity in commercial grade nitrogen, leads to a more distribution of the stabilizer in the polymer. The optimum activity of the bound stabilizer depends o ratio of stabilizer to initiator. This varies with the stabilizer, the polymer and the type of initiator system us The weight ratio, however, is normally from 100:1 to 0.25:1 especially 10:1 to 0.25:1, the range 20:1 to 0.5:1, especia 15:1 to 0.75:1 is preferred in the case of peroxide initiat When the stabilizer is used to modify the properties of polymer, it will generally be added in an amount of from 0. to 10 percent, typically 0.05 to 3 percent, more usually 0. to 2 percent by weight based upon the weight of the polymer When, on the other hand, the stabilizer is added to form an adduct which can be used to modify the properties of anothe polymer, larger quantities can be used. Typically up to 15 30 percent by weight may be preferred. The temperature at which the reaction by means of which stabilizer becomes bonded to the polymer is carried out wil naturally depend upon the radical concentration in the medium. In general, temperatures from 0 to 325 C will be suitable. Below the preferred temperature range uneconomic long reaction times or uneconomical amounts of initiator ma required. Above the desired temperature range, undesirable secondary reactions may occur. In chemical-mechanical processes where no initiator is present, the temperature us will depend largely upon the nature of the polymer; for low density polyethylene a temperature in the order of 150 C is generally suitable. This procedure provides a very convenient way of producing a polymer bound stabilizer by direct grafting during manufacture or in subsequent processing. It may be especially desirable to prepare masterbatches, that is polymers containing a high stabilizer concentration. Polymers produced in this way may be used as additives for unmodified polymers of the same chemical substrate composition or polymers having an essentially different substrate structure. The resulting solid polymers produced may also be used as additives to confer oxidative stability on the other polymers. As with conventional stabilizers, more than one of the above-mentioned compounds may be reacted together with the polymer to give bound synergistic stabilizer systems. The following examples serve to further illustrate the subject matter of the invention. Unless otherwise indicated, the parts and precentages are by weight. EXAMPLE 1 Preparation of mono-(3,3,5,5-tetramethyl-4- piperidinyl)maleate (MPME) : Equimolar quantities of maleic anhydride and 2,2,6,6- tetramethyl-4-hydroxypiρeridine were heated in benzene (approximately a 20% solution) under reflux for 1 hour. On cooling, part of the half ester precipitated. The solvent was evaporated to give the half ester in 95% yield. The ssoolliidd hhaadd IR, *H NMR, and 13C NMR consistent with the structure. EXAMPLE 2 Preparation of bis ( 3 , 3 , 5 , 5-tetramethyl-4-ρiperidinyl) maleate (BPME) : A mixture of 10. g of dimethyl maleate, 25.Og of 4-hydroxyl-2,2,6,6-tetramethylpiρeridine, and 15 drops of titanium (IV) isopropoxide in 100 ml of xylene were heated to a gentle boil with slow distillation of evolved methanol. After 20 hours, the reaction was cooled and 0.1ml of water and 5g of celite were added. The mixture was filtered, solvent removed under reduced pressure, and 100ml of hexanes were added. After cooling briefly to -20°C, the solid was collected by filtration and washed with water. After drying, 25.2g of product was oobbttaaiinneedd ((mm.p. 80-82°C; spectral data consistent with structure) . EXAMPLE 3 Preparation of bis(3,3,5,5-tetramethyl-4-piperidinyl) furmarate (BPFE) : Using the procedure of Example 2, reaction of 12.5g of 4-hydroxy-2,2,6,6 tetramethylpiperidine, 5.2g of dimethyl fumarate, and 0.2ml of the titanate in 150ml xylene gave 13.5g of the white bis fumarate, m.p. 156-159°C (spectral data consistent with structure). EXAMPLE 4 Preparation of bis(3,3,5,5-tetramethyl-4-piperidinyl) itaconate (BPIE: Using the procedure of Example 2, reaction of 6.0g of dimethyl itaconate, 12.5g of 4-hydroxy-2,2, 6,6-tetramethylpiperidine, and 0.1ml of the titanate in 90ml of xylenes gave 8.3g of the white bis itaconate, m.p. 77-81 C (spectral data consistent with structure) . EXAMPLE 5 Preparation of N,N'-bis(3,3,5,5-tetramethyl-4-piρeridinyl) maleami e (BPMA) : Reaction of 7.9g of 4-amino-2,2,6,6-tetramethylpiperidine and 3.1g of dimethyl maleate in 80ml of boiling xylenes for 5 dyas gave (after work-up as in Example 2) 3.5g of the bis amide, m.p. 142-147°C (spectral data consistent with structure) . EXAMPLE 6 Preparation of N-(3,3,5,5-tetramethyl-4-piperidinyl) maleimide (PMI) : Equal molar quantities of maleic anhdride and triacetonediamine were combined in ether giving a white precipitate which was dried to give the intermediate maleamic acid. The maleamic acid, 16.0, 1.4g of sodium acetate and 60m; of acetic anhydride was heated at 90 C for 2 hours. The mixture was cooled and the precipitate which formed was filtered. The precipitate was dissolved in water and extracted with choloroform. Evaporation of the choloroform gave a tan solid. Infrared and NMR spectroscopic analysis were consistent with the expected structure (C=0,1705 cm " ) . EXAMPLES 7-33 Preparation of polymer bound stabilizers - general procedure: Polymer, reactive additive, and initiator were melt processed in a Brabender torque rheometer at 70 rpm. The type of polymer, additive concentration, peroxide initiator concentration, reaction time, and melt temperature are shown in Table 1. The resulting compositions were analyzed quantitatively for extent of binding by GC analysis of methylene choloride extracts and qualitatively by IR of extracted films. The results are shown in the table. TABLE 1 REACTION CONDITIONS EXAMPLE # POLYMER % ADDITIVE " % PEROXIDE - TIMEfMINS.) TEMP.(-C.) % REACTED 7 PP 10% MPME 0.15% Di-Cup R 10 180 NA 3 8 P 10% BPIE 1.8% Varox DBPH 20 180 NA 3 9 PP 10% BPFE 1.8% Varox DBPH 20 180 90% 10 PP 10% BPMA 1.8% Varox DBPH 20 180 NA 3 11 PP 8.9% PMI 0.3% Vul-Cup R 20 180 NA 3 12 PP 10% BPME 1.0% Vul-Cuo R 5 200 75 13 PP 10% BPME 1.0% Di-Cup R 10 180 60 14 PP 10% BPME 1.1% Varox DBPH 20 180 70 15 P 10% BPME 1.0% Vul-Cup R 20 180 71 16 PP 10% BPME 2.5% BPME 20 180 87 17 PP 1.0% BPME 0.2% Lupersol 130 30 180 77 18 PP 3.0% BPME 0.2% Lupersol 130 30 180 69 19 PP 5.0% BPME 0.2% Lupersol 130 30 180 64 20 PP 2.5% BPME 0.43% Varox DBPH 20 180 83 21 PP 5.0% BPME 0.87% Varox DBPH 20 180 85 22 PP 7.5% BPME 1.3% Varox DBPH 20 180 86 23 PP 10% BPME 1.7% Varox DBPH 20 180 88 24 PP 15% BPME 2.6% Varox DBPH 20 180 91 25 PP 10% BPME 0.87% Varox DBPH 20 180 79 26 PP 10% BPME 2.6% Varox DBPH 20 180 94 27 PP 10% BPME 4.3% Varox DBPH 20 180 95 TABLE 1 CON'T) REACTION CONDITIONS EXAMPLE it POLYMER % ADDITIVE ~ % PEROXIDE ~ TIMECMINS.) TEMP.(-C) % REACTED 28 PP 10% BPME 6.1% Varox DBPH 20 180 95 29 LDPE 5.0% BPME 1.0% Di-Cup R 20 180 95 30 LDPE 10.0% BPME 1.7% Varox DBPH 20 180 95 31 EPDM 5.0% BPME 1.0% Di-Cup R 20 180 92 32 APP . 5.0% BPME 0.87% Varox DBPH 20 180 81 33 APP 10.0% BPME 1.7% Varox DBPH 20 180 94 BASED ON WEIGHT OF POLYMER; ABBREVIATIONS FROM EXAMPLES 1-6 2 BASED ON WEIGHT OF POLYMER; DI-CUP R = BIS(TERT-BUTYLPEROXYISOPROPYL)BENZENE; LUPERSOL 130 = 2,5-DI(T-BUTYLPER0XY)-3-HEXYNE; VAROX DBPH = 2,5-DIMETHYL-2,5-DI(T-BUTYLPER0XY) HEXANE EXAMPLE 34 A composition was prepared by melt processing 4.0g of BPME and 36.Og of polypropylene under conditions similar to Examples 7-33 (20 minutes at 180°C) but with no added peroxide. Analysis of the resulting polymer by IR of a methylene chloride extracted film and by GC of the extract indicated that, within the limits of the analysis, little or none of the BPME had reacted with or become bound to the polymer. EXAMPLE 35 Some of the polymer bound stabilizers from Examples 7-33 were evaluated for relative UV stabilization activity in polypropylene. The masterbatch were diluted to 0.2% active stabilizer concentration in polypropylene powder containing 0.1% calcium stearate and 0.1% Goodrite 3114 hindered phenolic antioxidant. After melt compounding (5 minutes at 200°C) , compression molded films were prepared (ca. 7-10 mils thick). The samples were exposed in a Xenon Weatherometer and tested periodically for embrittlement using a manual bend test. The results are shown in Table 2. TABLE 2 Hours To Failure Additive ___.,_<_. In Xenon Weatherometer 2% of product from Example 8 850 2% of product from Example 10 1000 2% of product from Exam le 15 1600 20% of product from Example 17 850 6.7% of product f om Example 18 900 4% of product from Example 19 1050 8% of product from Example 20 700 4% of product from Example 21 750 2.7% of product from Example 22 1000 2% of product from Exam le 23 800 2% of product from Example 26 900 2% of product from Example 27 700 2% of product f om Example 28 700 2% of product from Example 30 800 4% of product from Exam le 32 700 2% of product from Exam le 33 800 Control 1 250 BAse Resin: Profax 6501 Polypropylene 0.1% Calcium Stearate 0.1% Goodrite 3114 '0.2% Active UV Stabilizer Concentration EXAMPLE 36 Two of the polymer bound stabilizers from Examples 7-32 were evaluated for UV and thermal stabilization activity in thin film relative to the commercially available, unbound stabilizers in Chimassorb 944 and Tinuvin 770 (Ciba-Geigy Corp.). The base formulation was the same as in Example 35. Samples were prepared by melt compounding followed by extrusion of film (1-2 mils thick). Testing results are shown in Table 3. TABLE 3 Failiire In Hours to therometer at 150C Additives 1.2 Non Extracted Extracted Not extracted 1% of product from Example 14 1735 755 110 1% of product from Example 33 1850 1250 240 0.1% Chimasorb 944 1250 635 110 0.1% Tinuvin 770 756 100 60 Control 250 100 50 Base Resin: Profax 6501 PP 0.1% Calcium Stearate 0.1% Goodrite 3114 2 0.1% Active UV Stabilizer concentration 3 Extracted 24 Hours With -Acetone Before Testing EXAMPLE 37 SYNTHESIS OF 4-ANILINOPHENYL MALEAMIC ACID Equimolar quantities of maleic anhydride and 4-aminodiphenylamine were dissolved in chloroform. The resultant orange precipitate was collected after 30 minutes, filtered and dried in vacuo and was characterized as having a melting point of 183 C. EXAMPLE 38 SYNTHESIS OF 4-ANILINOPHENYLMALEIMIDE (AMI) Fifty grams of AMA were dissolved in 200cm acetic anhydride containing 4 grams of sodium acetate. The resulting solution was heated to 70°C for a period of 10 minutes. On cooling, a scarlet precipitate formed which was filtered and washed with cold methanol. The product was dried in vacuo and showed a melting point of 163°C. EXAMPLE 39 REACTION OF AMI WITH POLYPROPYLENE AMI, 0.080g, and 0.080g of dicumylperoxide in 39.92g of polypropylene were processed in a closed torque rheometer at 180°C for 10 minutes. The polymer was compression molded into film (10 mil) . The film was extracted with hot methylene chloride and the thermal oxidative stability of the film at 150°C was compared both before and after extraction with similar films containing a commercial heat stabilizer. The results are shown in Table 4 for several concentrations of additive. TABLE 4 COMPARISON OF AMI BOUND IN POLYPROPYLENE BEFORE AND AFTER EXTRACTION WITH A COMMERCIAL HEAT STABILIZED FORMULATION (HOURS TO EMBRITTLEMENT) Before After Formulation Extraction Extraction 0.2% AMI 1272 782 0.5% AMI 2035 1682 1.0% AMI 2372 1890 0.2% Irganox 1010* 775599 24 0.5% Irganox 1010 11332255 24 1.0% Irganox 1010 1483 24 * A commercial antioxidant available from Ciba-Geigy Corporation EXAMPLE 40 SYNTHESIS OF BIS-3(3,5-DITERTBUTYL-4-HYDROXYPHENYL) PROPYLMALEATE (BPPM) To 100ml of xylene was added 10.Og of 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanol, 2.7g of dimethylmaleate and 10 drops of titanium isopropoxide. The solution was refluxed over a Dean-Stark trap until the theoretical amount of methanol had distilled. The cooled solution was washed with water and evaporated. The oily residue was recrystallized from hexane to give a solid with a melting point of 87-90°C. EXAMPLE 41 REACTION OF BPPM WITH POLYPROYLENE BPPM was bound to polypropylene in a manner analogous to Example 39. Thus 0.080g of BPPM, 39.92g of polypropylene and 0.058g of Varoc DBPH were processed in a torque rheometer to give a mixture containing 65% bound additive by ultraviolet spectroscopic analysis. EXAMPLE 42 SYNTHESIS OF BIS-(2-ETHYLTHIOETHYL) MALEATE (BETEM) Ethylhydroxyethylsulfide, 21.2g, was combined with 14.g of dimethylmaleate and 10 drops of titanium isopropoxide in 100ml of xylene. The solution was refluxed until the theoretical amount of methanol had distilled. The mixture was washed with water, evaporated to dryness and distilled (bp. 150°/0.05mm) to give a colorless liquid. When BETEM was reacted with polypropylene according to Example 39, it reacted to the extent of 100% as determined by gas chromatography.

Claims: CLAIMS 1. A method for preparing a polymer bound stabilizer which comprises reacting a stabilizer precursor molecule containing a reactive double bond which is not readily homopolymerizable with a preformed polymer in the presence of a free radical. 2. A method for preparing a polymer bound stabilizer which comprises reacting a stabilizer precursor molecule with a preformed polymer in the presence of a free radical wherein said stabilizer precursor molecule is represented by the formula: 0 0 0 II II R-0C-CH=CH-C -A 1 II A R l 0 0 CH-CO-A * ° II II 2 I1 A-NC-CH=CH-C.J-A ' 0 | 1 1 I R R, which R and R. are independently selected from hydrogen, or an alkyl group containing from 1 to about 18 carbon atoms, and in which A, A* and A" are independently selected from in which n is integer from 1 to about 6, and R 2 and R_ are independently selected from methyl, t-butyl, or phenyl, or in which R 4 is hydrogen, oxygen, or an alkyl or aryl group containing from 1 to about 8 carbon atoms; or §r "^ © or -(CH 2 ) n ,SR 5 in which n' is an integer from 1 to about 18 and R g is hydrogen or an alkyl group containing from 1 to about 18 carbon atoms, or or in which R fi and R~ are independently selected from hydrogen, methyl, or ethyl and n" is an integer from 0 to about 10, or in which Ro Q is selected from hydrogen or an alkyl or aryl group containing from 1 to about 10 carbon atoms, and M is Ni or Zn. A method for preparing a polymer bound stabilizer which comprises reacting a stabilizer precursor molecule into a preformed polymer in the presence of a free radical wherein said stabilizer precursor molecule is selected from '-A' in which: X and X* are independently selected from oxygen or nitrogen: Y and Z are independently selected from H, C 1 ~C 18 alk y**- 5 rou P s ° r 0 ll —C-X—A" in which X is as defined above, A is selected from chain breaking antioxidants and their precursors peroxide decomposer functionality, an ultraviolet light screening functionality, a metal deactivator functionality and a triplet quencher functionality; A' and A" are independently selected from A, Y or Z. 4. The method according to claim 3 wherein said stabilizer precursor molecules are hindered piperidine stabilizers selected from the group consisting of: where R- is selected from hydrogen or a lower alkyl group containing up to 8 carbon atoms. The method according to claim 3 wherein said stabilizer precursor molecules are hindered phenol antioxidants in which A, A' and A" are independently selected from the group consisting of: where m = 1-6 and R g is selected from hydrogen or an alkyl group containing from 1 to about 8 crbon atoms. 6. The method according to claim 3 wherein said stabilizer precursor moleules are arylamine antioxidants selected from the group consting of: and 7. The method according to claim 3 wherein said stabilizer precursor molecules are ultraviolet light absorbing stabilizers selected from the group consisting of: <^>- and where n = 1 to 6 and R c is selected from hydroygen or an alkyl group containing from 1 to about 18 carbon atoms. 8. The method according to claim 3 wherein said stabilizer precursor molecules are peroxide decomposing antioxidants selected from the group consisting of: where n' is an integer of from 1 to about 18 and R c is selected from hydrogen or an alkyl group containing from 1 to about 18 carbon atoms. 9. The method according to claim 2 wherein said stabilizer precursor molecules are metal deactivating stabilizers selected from the group consisting of: 0 0 0 II II II R_.CN-N-CCH=CHC-0-R c 3 I I 5 H H where R,- is selected from hydrogen or an alkyl group containing from 1 to about 18 carbon atoms. "10. The method according to claim 1 wherein said preformed polymer is selected from polyolefin homopolymers and copolymers, rubber modified polyolefins, polystyrene, rubber modified polystyrene, polyvinyl chloride, polyamides, polyesters, and acrylonitrile butadiene styrene. 11. The process of claim 10 wherein said polymer is one having less than 15 percent unsaturation and is reacted with said stabilizer precursor molecule to form a masterbatch concentrate of polymer bound stabilizer. 12. The method according to claim 1 wherein said free radical is generated by a mechano-chemical procedure, 13. The method according to claim 1 wherein said free radical is generated by means of actinic radiation. 14. The method according to claim 1 wherein said free radical is generated by means of the addition of a free radical initiator. 15. The method according to claim 1 wherein said free radical is generated by prior oxidation of the polymer.

Inventors: REKERS JOHN, SCOTT GERALD, REKERS, JOHN, SCOTT, GERALD
Applicants: RESEARCH CORP, RESEARCH CORPORATION LIMITED
Application year: 1988
Main classification: C08F8
IPC codes: C08F8, C08F271, C08G85, C08K5, C08L101