MXPA97010211A - Delayed depolimerization of poly (methyl methacrylate) grafted in a propil polymer - Google Patents

Abstract

The present invention relates to a composition comprising (1) a polymeric material comprising a graft copolymer comprising a basic structure of a propylene polymer material having graft polymerized in the same poly (methyl methacrylate) or a methyl methacrylate copolymer and at least one comonomer, wherein the total amount of the polymerized monomer is from about 10 parts to about 120 parts per hundred parts of the propylene polymer material and the comonomer, when present, there is an amount up to about 20 mole percent of the total polymerized monomers, and (2) from about 0.025 parts to about 5.0 parts of a hydroxylamine compound having the formula T1T2NOH, wherein T1 is an alkyl group of 1 to 36 carbon atoms, one group of cycloalkyl of 5 to 12 carbon atoms, a group of aralkyl of 7 to 9 carbon atoms, or the aralkyl group substituted by an alkyl group of 1 to 4 carbon atoms or by one or two halo atoms and T 2 is hydrogen or has the same meaning as T 1, per hundred parts of the polymer material

Description

"DELAYED DEPOLIMERIZATION OF POLY (METHYL METHACRYLATE) GRAFTED IN A PROPYLENE POLYMER" This invention relates to a method for retarding the depolymerization of poly (methyl methacrylate) (PMMA) during the melt processing of a graft copolymer prepared by graft polymerization (a) methyl methacrylate (MMA) or (b) a copolymer of methyl methacrylate and one or more comonomers in a basic structure of the propylene polymer material so that the side chains of the PMMA or MMA copolymers are formed. When the methyl methacrylate is polymerized by grafting into a basic structure of the propylene polymer material the product contains a certain amount of free monomer. When the resulting graft copolymer is subjected to melt processing, e.g., extrusion and / or molding, the depolymerization occurs and an additional monomer is formed. The free monomer in the graft copolymer can lead to surface irregularities known as "spreading" and can produce an odor in the finished product. The conventional method for limiting depolymerization is to copolymerize methyl methacrylate with a monomer that acts as a chain stopper during the depolymerization reaction, e.g., methyl methacrylate, even though this method does not completely eliminate depolymerization. European Patent Application Number 726,289 discloses the addition of compounds containing a group of = N-0, e.g., a group of 2, 2, 6, 6, -tetramethyl-1-piperidinyloxy, to a polymer to inhibit undesirable reactions during heating, e.g., to inhibit the depolymerization of polystyrene or poly (methyl methacrylate) during thermal processing, or to inhibit crosslinking of unsaturated polymers such as polybutadiene or copolymers of butadiene and styrene during thermal grafting with compounds such as methacrylic acid. U.S. Patent No. 4,668,721 discloses the use of hydroxylamine derivatives to stabilize polyolefins against degradation or discoloration after extrusion at high temperature, exposure to the combustion products of natural gas or gamma irradiation, or during storage for extended periods. U.S. Patent No. 4,876,300 discloses the use of long chain N, N-dialkylhydroxylamines as process stabilizers for polyolefins that are processed at elevated temperatures. The process of this invention to retard the depolymerization of poly (methyl methacrylate) that has been graft polymerized into a basic structure of the propylene polymer material comprises mixing about 0.025 to about 5.0 parts of a hydroxylamine compound having the formula T1T2NOH, where T] _ is an alkyl group of from 1 to 36 carbon atoms, a group of carbonyl of from 5 to 12 carbon atoms, an aralkyl group of from 7 to 9 carbon atoms or the alkyl group substituted by an alkyl group of 1 to 4 carbon atoms or by one or two halogen atoms and T2 is hydrogen or has the same meaning as T, per hundred parts of a graft copolymer comprising a basic structure of a polymer material of propylene which has polymerized by grafting in the same poly (methyl methacrylate) or a copolymer of methyl methacrylate and at least one other monomer, wherein the total amount of the The polymerized monomers are from about 20 parts to about 120 parts by weight per 100 parts of the propylene polymer material, and the comonomer, when present, exists in an amount up to 20 mole percent of the total polymerized monomers. The use of the hydroxylamine additive makes it possible to reduce the content of the monomer and the value to a certain processing temperature, or to carry out the fusion processing at a higher temperature, that is, to expand the operating window, without increasing the content of the monomer or the smell of the final product. The material of the propylene polymer that is used as the basic structure of the graft copolymer of this invention can be (a) a propylene homopolymer; (b) a random copolymer of propylene and an olefin selected from the group consisting of ethene and alpha-olefins of 4 to 10 carbon atoms, so long as the olefin is ethylene, the maximum polymerized ethylene content is about 10 percent, preferably about 4 percent by weight, and when the olefin is an alpha-olefin of 4 to 10 carbon atoms, the maximum polymerized content thereof is about 20 percent, preferably about 16 percent. cent in weight; (c) a random propylene terpolymer and an olefin selected from the group consisting of ethylene and alpha-olefins of 4 to 8 carbon atoms, as long as the alpha-olefin content of 4 to 8 carbon atoms The polymerized maximum is about 20 percent, preferably about 16 percent by weight, and when the ethylene is one of the olefins, the maximum polymerized ethylene content is about 5 percent, preferably about 4 percent by weight; (d) an olefin polymer composition consisting essentially of: (i) from 10 percent to 50 percent of a polypropylene homopolymer having an isotactic index preferably of 85 percent to 98 percent, or a copolymer that is selected from the group consisting of (a) propylene and ethylene, (b) propylene, ethylene and an alpha-olefin of CH2 = CHR, wherein R is a straight or branched alkyl group of 2 to 8 carbon atoms and ( c) propylene and an alpha-olefin as defined above in (i) (b), (ii) from 5 percent to 20 percent of an essentially semicrystalline linear copolymer fraction having a crystallinity of about 20 percent one hundred to 60 percent, by differential scanning calorimetry (DSC), wherein the copolymer is selected from the group consisting of (a) ethylene and propylene containing more than 50 percent etiien; (b) ethylene, propylene and an alpha-olefin as defined above in (i) (b), which contains from 1 percent to 10 percent of an alpha-olefin and more than 55 percent to 98 percent a hundred percent of ethereal and alpha-olefin, and (c) ethylene and an alpha-olefin as defined in (i) (b), which contains more than 55 percent to 98 percent of the alpha-olefin, whose copolymer is insoluble in xylene at room temperature, and (iii) from 40 percent to 80 percent of a copolymer fraction that is selected from the group consisting of a copolymer of (a) ethylene and propylene, wherein the copolymer contains percent to less than 40 percent etiieno; (b) ethylene, propylene and an alpha-olefin as defined in (i) (b) wherein the alpha-olefin is present in an amount of 1 percent to 10 percent, and the amount of ethylene and alpha-olefin present is 20 percent to less than 40 percent; and (c) ethylene and an alpha-olefin as defined in (i) (b), which contains from 20 percent to less than 40 percent of the alpha-olefin, and optionally from 0.5 percent to 10 percent of a diene, the fraction of the copolymer being soluble in xylene at room temperature and having an intrinsic viscosity of 1.7 to 3.0 deciliters per gram, wherein the total amount of the fractions (ii) and (iii) based on the polymer composition of Total olefin is from about 65 percent to 80 percent, the weight ratio of (ii) / (iii) is frequently from 0.1 to about 0.3, and the total ethylene or alpha-olefin content from 4 to 8 carbon atoms or a combination thereof in (ii) + (iii) is less than 50 percent, and (e) a thermoplastic olefin consisting essentially of (i) from 10 percent to 60 percent of a propylene homopolymer that has an isotactic index greater than 90, or a crystalline propylene copolymer with ethylene and / or alpha-olefin of 4 to 8 carbon atoms having a propylene content greater than 85 percent, and an isotactic index greater than 85 percent; (iii) from 30 percent to 60 percent of an amorphous ethylene / propylene copolymer fraction optionally containing 0.5 percent to 10 percent of a diene, which is soluble in xylene at room temperature and which contends 40 one hundred to 70 percent etiieno; and (iii) from 8 percent to 40 percent of a semi-crystalline ethylene / propylene copolymer that is insoluble in xylene at room temperature. The ambient temperature is ~ 25 ° C. The α-olefin of 4 to 10 carbon atoms useful in the preparation of the propylene polymer materials (d) and (e) includes for example, buten-1; penten-1; hexen-1; 4-methyl-l-pentene and octene. The diene, when present, is typically a butadiene; 1,4-hexadiene, 1,5-hexadiene or ethylidenenorbornene.

The propylene polymer materials (d) and (e) can be prepared by polymerization in at least two stages, wherein in the first stage propylene or propylene and ethylene or alpha-olefin, or propylene and ethylene and alpha- olefin are polymerized to form component (i) of (d) or (e), and in the following steps, mixtures of ethylene and propylene or alpha-olefin, or of ethylene, propylene and alpha-olefin, and optionally a diene, they are polymerized to form the components (ii) and (iii) of (d) or (e). The polymerization can be carried out in a liquid phase, gas phase or liquid-gas phase using separate reactors, all of which can be carried out either intermittently or continuously. For example, it is possible to carry out the polymerization of component (i) using the liquid propylene as a diluent and the polymerization of the components (ii) and (iii) in the gas phase without intermediate steps except as regards the partial degassing of propylene. This is the preferred method. The preparation of propylene polymer materials (b) and (c) is described in greater detail in U.S. Patent No. 5,409,992, the process of which is incorporated herein by reference.

Polypropylene homopolymer is the preferred basic propylene polymer structure material. The monomers which form the graft polymers or copolymers in the basic structure of the propylene polymer material are methyl methacrylate or a mixture of methyl methacrylate and one or more monomers which act as chain retainers during the depolymerization reaction. Suitable monomers include, for example, methyl acrylate, ethyl acrylate, cyclohexyl acrylate, styrene, butyl acrylate, 2-ethylhexyl acrylate, acrylic acid, methacrylic acid and acrylonitrile. During graft polymerization, the monomers are also polymerized to form a certain amount of free or ungrafted polymer or copolymer. Any reference to "polymerized monomers" in this specification is meant to include polymerized monomers both grafted and ungrafted. The polymerized monomers comprise from about 10 parts to about 120 parts per hundred parts of the propylene polymer material, preferably from about 30 to about 100 pph. The morphology of the graft copolymer is such that the propylene polymer material is the continuous phase or the matrix phase and the copolymer of PMMA or methyl methacrylate copolymer both grafted and ungrafted which are in a dispersed phase. When a comonomer is used for the graft polymerization, the comonomer comprises up to 20 mole percent, preferably from about 2 mole percent to about 10 mole percent of the total monomers. The graft copolymer can be made according to any of several methods. One of these methods involves forming active graft sites in the propylene polymer material, either in the presence of the graft monomers or followed by treatment with the monomers. The grafting sites can be produced by treatment with a peroxide or other chemical compound which is a free radical polymerization initiator or by irradiation with high energy ionization radiation. The free radicals produced in the polymer resulting in the chemical treatment or the oxidation treatment form the active grafting sites in the polymer and initiate the polymerization of the monomers at these sites. Graft copolymers produced by peroxide-initiated grafting methods are preferred. In the peroxide initiated method, the propylene polymer material is treated at a temperature of about 60 ° C to about 125 ° C, preferably about 80 ° C to about 120 ° C, with about 0.1 to about 6, preferably from about 0.2 to about 3.0, pph (parts by weight per 100 parts by weight of the propylene polymer material) of an initiator having a half-life of decomposition of about 1 to about 240, preferably about 5. to about 100, and more preferably from about 10 to about 40 minutes at the temperature employed. Organic peroxides, and especially those that generate alkoxy radicals, constitute the class of preferred initiators. These include acyl peroxides, such as benzoyl peroxides and dibenzoyl; dialkyl and aralkyl peroxides, such as tertiary butyl peroxide, dicumyl peroxide, cumyl butyl peroxide, 1,1-tert-butylperoxy-3,5,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di. -tert-butylperoxyhexane, and bis (alpha-tert-butylperoxyisopropylbenzene); peroxy esters, such as tertiary butylperoxy pivalate, tertiary butyl perbenzoate, 2,5-dimethylhexyl-2, 5-di (perbenzoate), tertiary butyl di (perftalate), tert-butylperoxy-2-ethylhexanoate; 1,1-dimethyl-3-hydroxybutylperoxy-2-ethylhexanoate; and peroxy carbonates, such as di (n-propyl) peroxy di (2-ethylhexyl) peroxy dicarbonate dicarbonate and di (4-tert-butylcyclohexyl) peroxy dicarbonate. Through a period that coincides with, or follows, the period of the initiator treatment, with or without overlap, the propylene polymer material is treated with from about 10 percent to about 50 percent by weight of the graft monomers based on the total weight of the propylene polymer material and the graft monomers used, at an addition rate not exceeding about 4.5, preferably 3.0, and more preferably about 2.0 pph per minute, at any level of addition of monomer. If the monomers are added after the addition period of the initiator, preferably no more than about 2.5 half-lives of the initiator separate the initiator and monomer addition periods. After the grafting period, any of the unreacted monomers are removed from the resulting grafted propylene polymer material and any unreacted initiator is decomposed and any residual free radicals are deactivated, preferably by heating, generally at a temperature of at least 100 ° C for at least 5 minutes, preferably at least 120 ° C for at least 20 minutes. A non-oxidizing environment is maintained throughout the process. The term "essentially non-oxidizing", when used herein to describe the environment or atmosphere, to which the olefin polymer material is exposed means an environment in which the concentration of active oxygen, i.e. Oxygen concentration in a form that will react with the free radicals in the irradiated material is less than about 15 percent, preferably less than about 5 percent, and most preferably less than about 1 percent by volume. The especially preferred concentration of the active oxygen is 0.004 percent or less in volume. Within these limits, the non-oxidizing atmosphere can be any gas, or mixture of gases, that is oxidatively inert toward the free radicals in the olefin polymer material, e.g., nitrogen, argon, helium and carbon dioxide. In a method where the active graft sites are produced by irradiation, the propylene polymer material is irradiated at a temperature within the range of about 10 ° C to about 85 ° C with high energy ionization radiation, and the The irradiated polymer material is treated at a temperature of from about 10 ° C to about 100 ° C, preferably from about 10 ° C to about 70 ° C, and most preferably from about 10 ° C to about 50 ° C, during at least about 3 minutes, preferably at least about 10 minutes in a semi-intermittent process, with from about 10 percent to about 70 weight percent of the graft monomers, based on the total weight of the polymer material of propylene and the graft monomer used. Then, simultaneously successively in optional order, essentially all residual free radicals in the resulting grafted propylene polymer material are deactivated and any unreacted monomers are removed from the material. The propylene polymer material is maintained in an essentially non-oxidizing environment, eg. , under an inert gas, through the process at least until after the deactivation of the residual free radicals has been completed. The deactivation of the free radicals is preferably achieved by heating, e.g., at temperatures of at least 100 ° C, preferably of at least 120 ° C, and generally at least for 20 minutes.

The additive that is mixed with the graft copolymer to retard the depolymerization of PMMA is a hydroxylamine compound having the formula T1T2NOH, where T] _ is a group of 1 to 36 carbon atoms, a cycloalkyl group of 5 to 12 carbon atoms, an aralkyl group of 7 to 9 carbon atoms or the aralkyl group substituted by an alkyl group of 1 to 4 carbon atoms or by one or two halogen atoms and T2 is hydrogen or has the same meaning that T] _. Long chain N, N-dialkylhydroxylamines are preferred. A mixture of these long chain hydroxylamines is found in di (hydrogenated tallow) amine. The specific distribution of the alkyl substituents may vary, but the di (hydrogenated tallow) amine contains predominant amounts of N, N-dihexadelamine, N, N-dioctadecylamine and N-hexadecyl-N-octadecylamine. The long chain N, N-dialkylhydroxylamines can be prepared by a number of methods. These include (a) oxidation of the corresponding secondary amine with aqueous hydrogen peroxide to form the desired N, N-dialkylhydroxylamine directly; (b) the addition of a secondary amine to an alpha, beta-unsaturated compound, such as an alkyl acrylate to form a Michael addition product, which in turn is oxidized to the corresponding tertiary amine oxide using hydrogen peroxide aqueous, and followed by removal of the alpha, beta-unsaturated comix from the Cope reaction to provide the N, N-dialkylhydroxylamine; (c) the metathesis reaction between an alkyl halide and a hydroxylamine in the presence of alkali such as sodamide, and (d) the reaction of an amine with a peroxide compound such as benzoyl peroxide, followed by saponification of the intermediate formed in the desired hydroxylamine derivative. The hydroxylamine compound is present in an amount from about 0.025 to about 5.0, preferably from about 0.1 to about 2.5, parts per hundred parts of the graft copolymer. Suitable hydroxylamine compounds include, for example, bis (hydrogenated tallow alkyl) oxidized amines such as hydroxylamine FS-042 which can be obtained commercially from Ciba-Geigy; the stabilizer Fiberstab 210, which is a mixture of 50 percent of the hydroxylamine FS-042 and 50 percent of amine hindered Chi assorb 119 (90 percent of HALS A and 10 percent of Tinuvin 622 which is a hindered amine), also commercially available from Ciba-Geigy; hydroxylamine of dibenzyl, and t-amyl-t-butylnitroxide. HALS A is 1, 3, 5-triazin-2,4,6,6-triamine, N, N * '- [1,2-ethanediylbis [N' [4,6-bis [butyl] 1, 2, 2, 6, 6-pentamethyl-4-piperidinyl) amino] -1, 3, 5-triazin-2-ylamino] propyl] - [N ', N "-dibutyl-N1, N" -bis (1 , 2,2,6,6-pentamethyl-4-piperidinyl). The graft copolymer can also be mixed with one or more polymeric materials, such as, for example, polyolefin rubber, a mixture of polyolefin rubber and a core hull rubber, and propylene polymer materials of broad molecular weight distribution ( BMWP PP). The polyolefin rubber is a copolymer or terpolymer of ethylene and one or two alpha-olefins of 3 to 10 carbon atoms, ethylene / propylene copolymer rubbers, ethylene / butene and ethylene / octene. The core hull rubbers comprise small particles of the crosslinked rubber phase surrounded by a compatibilization helmet, typically a vitreous polymer or copolymer. The core is typically a diene rubber such as butadiene or isoprene, or an acrylate. The hull is typically a polymer of two or more monomers that are selected from styrene, methyl methacrylate and acrylonitrile. Particularly preferred core hull rubbers have an acrylate core.

When the polyolefin rubber or the mixture of polyolefin rubber and the core hull rubber is added to the composition without BM D PP, the rubber component is present in an amount from about 2 percent to about 40 percent and the Graft copolymer is present in an amount of about 60 percent to about 98 percent by weight. The propylene polymer material BMWD has an Mw / Mn of 8 to 60, preferably 12 to 40; a melt flow rate of 0.5 to 50, preferably 3 to 30 grams per 10 minutes, and insoluble xylene at 25 ° C in an amount greater than or equal to 94, preferably greater than or equal to 96 percent , and more preferably greater than or equal to 98 percent. When both the rubber component and the BMWD PP material are present in the composition the graft copolymer is present in an amount of about 20 percent to 90 percent, the BMWD PP mate is present in an amount of about 10 per cent. one hundred to about 70 percent, and the polyolefin rubber, or the mixture of polyolefin rubber and the core hull rubber is present in an amount of about 2 percent to about 40 percent by weight.

The propylene polymer material having a broad molecular weight distribution can be a propylene homopolymer or an impact modified propylene homopolymer of ethylene / propylene rubber, wherein the propylene homopolymer has a broad molecular weight distribution. The propylene polymer material BMWD can be prepared by sequential polymerization in at least two stages in the presence of a Ziegler-Natta catalyst supported on magnesium halides in active form. The fractions (A) and (B) are prepared in consecutive separate stages, operating in each stage in the presence of the polymer and the catalyst coming from the previous stage. The polymerization process can be carried out in an intermittent or continuous mode according to known techniques, operating in the liquid phase in the presence or absence of an inert diluent, or in the gas phase, or in the liquid phase. gas preferably in the gas phase. The preparation of the propylene polymer material BMWD is described in greater detail in US Pat. No. 5,286,791, the process of which is incorporated herein by reference. If polymer additives are present in the composition, the amount of the hydroxylamine compound is from about 0.025 to about 5.0, preferably from about 0.1 to about 2.5, parts per hundred, based on the total amount of the polymer in the composition. Other additives may also be present such as fillers or fillers, reinforcing agents, pigments, slip agents, waxes, oils, antiblocking agents and antioxidants. The hydroxylamine compounds are useful for retarding the depolymerization of PMMA at temperatures above the depolymerization temperature of PMMA, which are commonly reported in the literature as being from 250 ° C to 275 ° C, say, during operations of fusion processing such as, for example, extrusion, molding, film production, fiber production and thermoforming. The odor in the final product is also reduced. In the following examples, the MMA content in the graft copolymer was determined by weighing a 5 gram sample into a small serum bottle of 50 milliliter capacity to which 25 milliliters of acetone was added. The small bottle was sealed and weighed. The small sample vial was placed in an ultrasonic bath at room temperature and the sample was extracted for three hours. The small sample vial was then removed from the bath, cooled, heated and reweighed to determine the leak. Acetone was added to replace any weight loss due to evaporation. One microliter was separated from the sample by syringe and analyzed using gas chromatography equipped with an H2 flame ionozation detector, temperature programming and integration. The melt flow regime was determined at 230 ° C under a load of 3.2 kilograms according to the method D-1238 of the American Society for the Testing of Materials. In this specification, all parts and percentages are by weight unless otherwise stated.

Example 1 This example shows the effect on the amount of the monomer produced during the melt processing when different radical scavengers (antioxidants) were added to a graft copolymer comprising a basic structure of propylene homopolymer to which a methyl methacrylate copolymer was grafted / methyl acrylate. The amount of the monomer that was introduced into the reactor was 91.4 parts of methyl methacrylate (MA) and 3.6 parts of methyl acrylate (MMA) per hundred parts of the polypropylene. The conversion ratio of the monomer to polymer was 96.1 percent. The samples were combined in a Brabender single screw extrusion apparatus equipped with a 3: 1 compression, a 25 L / D ratio screw. Each sample was extruded to a flat profile of 220 ° C at 60 revolutions per minute in an air atmosphere. The samples were transferred immediately after being granulated into sealed glass jars, and subsequently analyzed for MMA content. The results are given in Table 1. In the table, BHT was butylated hydroxytoluene.; Stabilizer 1 was the Fiberstab 210 stabilizer, which can be obtained commercially from Ciba-Geigy, a mixture of 50 percent bis (hydrogenated tallow alkyl) oxidized amines FS-042 and 50 percent hindered amine Chimassorb 119 (90 percent HALS A and 10 percent hindered amine Tinuvin 622). Stabilizer 2 was the antioxidant Irganox 1010 which is 2,2-bis [[3,5-bis (1,1-dimethylethyl) -hydroxyphenyl)] -1-oxopropoxy] ethyl] -1,3-propanediyl-3, 5-bis (1,1-dimethylethyl) -4-hydroxybenzenpropanoate can also be obtained commercially from Ciba-Geigy.

Table 1 Sample No. 1 2 3 4 5 Graft Copolymer 100 100 100 100 100 B HT Stabilizer 1 0.5 Stabilizer 2 0.1 MMA (ppm) 2,000 1,150 685 70 70 The data shows that the Fiberstab 210 stabilizer provided the best results, taking into consideration the amount of the additive used.

Example 2 The data in Table 2 show that the hydroxylamine FS-042 was the component of the stabilizer Fiberstab 210 (Stabilizer 1) which was responsible for the reduction of the methyl methacrylate monomer. In the Table, the hindered amine was the hindered amine Chimassorb 119 (90 percent HALS A and 10 percent hindered amine Tinuvin 622). The graft copolymer was the same as in Example 1.

Table 2 Sample No.

Graft Copolymer 100 100 100 100 100 100 Ca stearate 0.1 0.1 0.1 0.1 0.1 0.1 Stabilizer 1 0.5 0.2 Hydroxylamine 0 0 0.25 0.1 Immune Amine 0.25 0.1 MFR, dg / min 4 4.1 3.7 4.6 7.6 MMA, ppm 60 50 75 60 1,040 1,300 Example 3 This example shows the effect of the processing temperature on the amount of the MMA monomer that occurs during the melt processing and a composition containing the Fiberstab 210 stabilizer, as well as a comparison with the amount of the monomer formed at each temperature, when the antioxidant Irganox B-215 was used instead of the Fiberstab 210 stabilizer. The samples were stirred in a Haake twin-screw laboratory extruder equipped with counter-rotating screws. Each sample was extruded at six different temperatures: 220 ° C, 240 ° C, 260 ° C, 280 °, 300 ° and 320 ° C. All samples were processed at 50 revolutions per minute in an air atmosphere. The samples were transferred immediately after granulation to sealed glass jars and analyzed to determine the content of the MMA monomer. Table 3 shows the composition of each sample. The graft copolymer was the same as in Example 1. The broad molecular weight distribution propylene homopolymer (BMWD PP) had a polydispersity index of 7.4, a melt flow rate of 1 gram per 10 minutes (Method D- 1238 of the American Society for the Testing of Materials, 230 ° C, 2.16 kilograms), and insoluble xylene at 25 ° C of 98.5 percent, and can be obtained commercially from Montell USA Inc. The rubber was the copolymer Engage 8150 etiieno / octene-1, which can be obtained commercially from the Dow Chemical Company. Stabilizer 1 was the stabilizer Fiberstab 210, and Stabilizer 3 was Irganox B-215, a mixture of 1 part of the antioxidant Irganox 1010 and 2 parts of the Irgafos 168, the stabilizer of tris (2,4-di-tert-butylphenyl) phosphite, which can be obtained commercially from Ciba-Geigy. The amounts of the additives in Table 3 are provided in part per hundred, based on the total amount of the polymer in the composition.

Table 3 Sample Number 1 2 Graft Copolymer 45 45 BMWD PP 50 50 Rubber 5 5 Ca stearate (pph) 0.1 0.1 Stabilizer 1 (pph) 0.2 0 Stabilizer 3 (pph) 0 0.25 Table 4 shows the amount of the monomer at the different temperatures for each of the samples. The designation "nt" represents "not proven".

Table 4 Extrusion Temperature, ° C 220 240 260 280 300 320 MMA, ppm (Sample 1) 50 100 300 720 1,520 2,750 MMA, ppm (Sample 2) 80 nt nt 2,770 nt 6,100 The data show that as the extrusion temperature is increased, the amount of MMA formed was much smaller when a hydroxylamine compound was present in the composition when the Irganox B-215 antioxidant was used. - 2! Example 4 This example shows the effect of using hydroxylamine FS-042 in the production of the MMA monomer after the melt processing of a graft copolymer comprising a basic structure of propylene homopolymer to which a poly (methyl methacrylate) was grafted or a copolymer of methyl methacrylate and methyl acrylate (MA) containing different amounts of methyl acrylate comonomer. Polymer 1 contained the comonomer MA and the conversion ratio of monomer to polymer was 96.1 percent. For Polymer 2, 90.8 parts of MMA and 4.2 parts of MA per hundred parts of the propylene homopolymer were introduced into the reactor. The conversion percentage was 94.2 percent. For Polymer 3, 88.8 parts of MMA and 6.2 parts of MA per hundred parts of propylene homopolymer were introduced into the reactor. The conversion percentage was 96.6 percent. Stabilizer 2 was the Irganox 1010 antioxidant that can be obtained commercially from Ciba-Geigy, and the hydroxylamine was bis (hydrogenated tallow alkyl) oxidized amine FS-042, also commercially obtained from Ciba-Geigy. The amounts of the additives of the formulations are given in parts per hundred parts of polymer (pph). Prior to fusion processing, the MMA content of all polymers was measured after drying under normal conditions (60 ° C for 12 hours). The graft copolymer was then stirred with the additives shown in Table 5 (parts by weight per 100 parts of the graft copolymer). All the samples were stirred in a Brabender single screw extruder equipped with a 25 L screw / D compression of 3: 1. The samples were extruded to a flat profile at 260 ° C at 60 revolutions per minute in an air atmosphere. Samples were transferred immediately after granulation to sealed glass jars, and subsequently analyzed for MMA content. The percentage reduction in MMA was calculated from a comparison between the weight percentage of MMA after the fusion processing, with and without hydroxylamine, ie a comparison of samples 1 and 2, 3 and 4, y, 5 and 6. The results are given in Table 5.

Table 5 Sample Number Polymer 1 (without MA) 100 100 Polymer 2 (5 mol% MA) 100 100 Polymer 3 (7.5 molar% of MA) 100 100 Ca stearate (pph) 0.05 0.05 0.05 0.05 0.05 0.05 Stabilizer 2 (pph) 0.1 - 0.1 - 0.1 Hydroxylamine (pph) - 0.1 - 0.1 - 0.1 ppm of MMA before the fusion processing 19 19 20 20 28 28 % by weight of MMA after the melt processing 1.206 0.385 0.48 0.193 0.777 0.146 % Reduction in MMA 68 76 The data shows that the use of hydroxylamine significantly reduced the amount of monomer that was generated during the fusion processing.

Example 5 This example demonstrates the effect of using different amounts of the hydroxylamine additive (parts per hundred, based on the total amount of polymer in the composition) on the MMA content of a graft copolymer alone and when mixed with the polymeric additives. The graft copolymer was a basic structure of the propylene homopolymer, to which a copolymer of methyl methacrylate / methyl acrylate was grafted. The amount of the monomer introduced into the reactor was 90.8 parts of MMA and 4.2 parts of MA per hundred parts of polypropylene. The percent conversion of the polymer monomer was 97.9 percent. All samples were stirred in a single screw Brabender extruder equipped with a 25 L / D compression ratio screw of 3: 1. The samples were extruded to a flat profile at 260 ° C at 60 revolutions per minute in an air atmosphere. The granules were transferred to sealed glass jars and subsequently analyzed to determine the residual content of MMA. The results are given in Tables 6 and 7. In Table 6, the base formulation was a mixture of 100 parts of the graft copolymer and 0.1 part of calcium stearate (CaSt) per hundred parts of the graft polymer. In Table 7, the base formulation was a mixture of (1) 45 parts of the graft copolymer, (2) 50 parts of the broad molecular weight distribution propylene homopolymer used in Example 3, (3) 5 parts of Engage 8150 ethylene / octene copolymer rubber, which can be obtained commercially from Dow Chemical Company, and (4) 0.1 part of calcium stearate per hundred parts of (1) + (2) + (3). The hydroxylamine was hydroxylamine FS-042.

Table 6 Hydroxylamine (pph) MMA (ppm) 8820 0. 025 4230 0.1 1930 711 Table 7 Hydroxylamine (pph) MMA (ppm) 4190 0.05 1150 0.1 890 0.25 640 0.5 270 360 510 Example 6 This example demonstrates the effect of using the various hydroxylamine compounds in the MMA content of a graft copolymer blended with polymeric additives. The graft copolymer was a basic structure of propylene homopolymer in which a copolymer of methyl methacrylate / methyl acrylate was grafted. The amount of monomer that is introduced into the reactor was 90.8 parts of MMA and 4.2 parts of MA per hundred parts of polypropylene. The conversion ratio of the monomer to polymer was 94.2 percent. The broad molecular weight distribution propylene rubber homopolymer was the same as in Example 3. Stabilizer 4 was bis (hydrogenated tallow alkyl) oxidized amines FS-042 which can be obtained commercially from Ciba-Geigy. Stabilizer 5 was dibenzyl hydroxylamine and Stabilizer 6 was t-amyl-t-butylnitroxide. All samples were stirred in a single screw Brabender extruder equipped with a 1.90 cm screw. The samples were extruded to a flat profile of 260 ° C at 60 revolutions per minute in an air atmosphere. The results are provided in Table 8.

Table 8 Sample Control Number Graft Copolymer 45 45 45 45 BMWD PP 50 50 50 50 Rubber CaSt (pph) .1 Stabilizer 4 (pph) .1 Stabilizer 5 (pph) Stabilizer 6 (pph) MMA (ppm) 4190 574 2070 1987 The other features, advantages and embodiments of the invention disclosed herein will be readily apparent to those skilled in the art after reading the above-cited exposures. In this regard, even though the specific embodiments of the invention have been described in considerable detail, variations and modifications of these embodiments may be made without departing from the spirit and scope of the invention as described and claimed.

Claims (13)

R E I V I N D I C A C I O N S

1. A composition comprising (1) a polymeric material comprising a graft copolymer comprising a basic structure of a propylene polymer material having graft polymerized in the same poly (methyl methacrylate) or a copolymer of methyl methacrylate and at least one comonomer, wherein the total amount of the polymerized monomer is from about 10 parts to about 120 parts per hundred parts of the propylene polymer material and the comonomer, when present, there is an amount up to about 20 molar percent of the total polymerized monomers, and (2) from about 0.025 part to about 5.0 parts of a hydroxylamine compound having the formula T] _T2NOH, wherein T] _ is an alkyl group of 1 to 36 carbon atoms, a group of cycloalkyl of 5 to 12 carbon atoms, an aralkyl group of 7 to 9 carbon atoms, or the aralkyl group substituted by a group of alkyl of 1 to 4 carbon atoms or by one or two halogen atoms and T2 is hydrogen or has the same meaning as T] _, per hundred parts of the polymeric material.

2. The composition of claim 1, wherein the propylene polymer material of the graft copolymer is selected from the group consisting of: (a) a propylene homopolymer; (b) a random propylene copolymer and an olefin selected from the group consisting of ethylene and α-olefins, of 4 to 10 carbon atoms, with the proviso that, when the olefin is ethylene, the ethylene content Maximum polymerized is about 10 weight percent, and when the olefin is an α-olefin of 4 to 10 carbon atoms, the maximum polymerized content thereof is about 20 weight percent; (c) a random propylene terpolymer and an olefin selected from the group consisting of ethylene and α-olefins of 4 to 8 carbon atoms, as long as the maximum content of the α-olefin of 4 to 8 carbon atoms The polymerized carbon is about 20 weight percent and, when the ethylene is one of the olefins, the maximum polymerized ethylene content is about 5 weight percent; (d) an olefin polymer composition consisting essentially of: (i) from 10 percent to 50 percent of a propylene homopolymer having an isotactic index preferably of 85 percent to 98 percent, or a copolymer that is selected from the group consisting of (a) propylene and ethylene, (b) propylene, ethylene and an α-olefin CH2 = CHR, wherein R is a straight or branched alkyl group of 2 to 8 carbon atoms, and ( c) propylene and an α-olefin as defined above in (i) (b); (ii) from 5 percent to 20 percent of a fraction of the essentially linear semi-crystalline copolymer having a crystallinity of about 20 percent to 60 percent, by differential scanning calorimetry (DSC), wherein the copolymer is selected from the group consisting of (a) ethylene and propylene which contain more than 55 percent ethylene; (b) ethylene, propylene and an α-olefin as defined above in (i) (b), which contains from 1 percent to 10 percent of the α-olefin and more than 55 percent up to 98 percent both ethene and alpha-olefin, and (c) ethylene and an α-olefin as defined in (i) (b), which contains more than 55 percent to 98 percent of the α-olefin, whose copolymer it is insoluble in xylene at room temperature; and (iii) from 40 percent to 80 percent of a copolymer fraction that is selected from the group consisting of a copolymer of (a) ethylene and propylene wherein the copolymer contains from 20 percent to less than 40 percent of etiieno; (b) ethylene, propylene and an α-olefin as defined in (i) (b), wherein the α-olefin is present in an amount of 1 percent to 10 percent, and the amount of ethylene and a- olefin present is from 20 percent to less than 40 percent; and (c) ethylene and an α-olefin as defined in (i) (b), which contains from 20 percent to less than 40 percent of the α-olefin, and optionally with 0.5 percent to 10 percent of a diene, the fraction of the copolymer is soluble in xylene at room temperature and has an intrinsic viscosity of 1.7 to 3.0 deciliters per gram, where the The total amount of the fractions of (ii) and (iii) based on the total olefin polymer composition is from about 65 percent to 80 percent, the weight ratio of (ii) / (iii) is from 0.1 to about

0. 3, and the total ethylene or α-olefin content of 4 to 8 carbon atoms or a combination thereof in (ii) + (iii) is less than 50 percent; and (c) a thermoplastic olefin consisting essentially of: (i) from 10 percent to 60 percent of a propylene homopolymer having an isotactic index greater than 90, or a crystalline propylene copolymer with ethylene and / or a -olefin of 4 to 8 carbon atoms having a propylene content greater than 85 percent and an isotactic index greater than 85 percent; (ii) from 30 percent to 60 percent of an amorphous ethylene / propylene copolymer fraction optionally containing 0.5 percent to 10 percent of a diene, which is soluble in xylene at room temperature, and which contains percent to 70 percent etiieno; and (iii) from 8 percent to 40 percent of a semicrystalline ethylene / propylene copolymer that is insoluble in xylene at room temperature.

3. The composition of claim 2, wherein the propylene polymer material is a propylene homopolymer.

4. The composition of claim 1, wherein the methyl methacrylate copolymer is a copolymer of methyl methacrylate and methyl acrylate.

The composition of claim 1, wherein the hydroxylamine compound is a bis (hydrogenated tallow alkyl) oxidized amine.

The composition of claim 1, wherein the polymeric material further comprises a polyolefin rubber and a polypropylene material of broad molecular weight distribution having an Mw / Mn of 8 to 60, a melt flow rate of 0.5. at 50 grams per 10 minutes, insoluble xylene at 25 ° C of more than or equal to 94 percent.

The composition of claim 6, wherein the broad molecular weight distribution propylene polymer material is a propylene homopolymer of molecular weight distribution.

8. A process for retarding the depolymerization of poly (methyl methacrylate) that has been polymerized by grafting into a basic structure of a propylene polymer material, the process comprising mixing from about 0.025 part to about 5.0 parts of a hydroxylamine compound having the formula T T 2 OH, wherein T] _ is an alkyl group of 1 to 36 carbon atoms, a cycloalkyl group of 5 to 12 carbon atoms, an aralkyl group of 7 to 9 carbon atoms, or the aralkyl group substituted by an alkyl group of 1 to 4 carbon atoms or by one or two halogen atoms and T2 is hydrogen or has the same meaning as T] _, per hundred parts of a polymeric material comprising a graft copolymer consisting of a basic structure of a propylene polymer material having graft polymerized to the same poly (methyl methacrylate) or a copolymer of methyl methacrylate and at least one other monomer, wherein the total amount of the polymerized monomer is from about 10 parts to about 120 parts per hundred parts of the propylene polymer material and the comonomer, when present, there is an amount up to 20 mole percent of the total polymerized monomers .

The process of claim 8, wherein the propylene polymer material of the graft copolymer is selected from the group consisting of: (a) a propylene homopolymer; (b) a random propylene copolymer and an olefin selected from the group consisting of ethylene and α-olefins, of 4 to 10 carbon atoms, provided that, when the olefin is ethylene, the maximum polymerized ethylene content. is about 10 weight percent, and when the olefin is an α-olefin of 4 to 10 carbon atoms, the maximum polymerized content thereof is about 20 weight percent; (c) a random propylene terpolymer and an olefin selected from the group consisting of ethylene and α-olefins of 4 to 8 carbon atoms, as long as the content of α-olefin of 4 to 8 polymerized carbon atoms maximum is about 20 weight percent and, when the ethylene is one of the olefins, the maximum content of polymerized ethylene is about 5 weight percent; (d) an olefin polymer composition consisting essentially of: (i) from 10 percent to 50 percent of a propylene homopolymer having an isotactic index preferably from 85 percent to 98 percent, or a selected copolymer of the group consisting of (a) propylene and ethylene, (b) propylene, ethylene and an α-olefin CH2 = CHR, wherein R is a straight alkyl group 0 branched from 2 to 8 carbon atoms, and (c) propylene and an α-olefin as defined above in (i) (b); (ii) from 5 percent to 20 percent of a fraction of the essentially linear semicrystalline copolymer having a crystallinity of about 20 percent to 60 percent, by differential scanning calorimetry (DSC), wherein the copolymer is selected from the group consisting of (a) ethylene and propylene which contain more than 55 percent ethylene; (b) ethylene, propylene and an α-olefin as defined in (i) (b) above, which contain 1 percent to 10 percent of an α-olefin and more than 55 percent to 98 percent of both ethene and alpha-olefin, and (c) ethylene and an α-olefin as defined in (i) ( b), which contain more than 55 percent to 98 percent of the α-olefin, whose copolymer is insoluble in xylene at room temperature; Y (iii) from 40 percent to 80 percent of a fraction of the copolymer selected from the group consisting of a copolymer of (a) ethylene and propylene wherein the copolymer contains from 20 percent to less than 40 percent ethylene.; (b) ethylene, propylene and an α-olefin as defined in (i) (b), wherein the α-olefin is present in an amount of 1 percent to 10 percent, and the amount of ethylene and the -olefin present is from 20 percent to less than 40 percent; and (c) ethylene and an α-olefin as defined in (i) (b), containing from 20 percent to less than 40 percent of the α-olefin, and optionally from 0.5 percent to 10 percent of a diene, the fraction of the copolymer is soluble in xylene at room temperature and has an intrinsic viscosity of 1.7 to 3.0 deciliters per gram, wherein the total amount of the fractions of (ii) and (iii) based on the composition of the polymer of total olefin is from about 65 percent to 80 percent, the weight ratio of (ii) / (iii) is from 0.1 to about 0.3, and the total ethylene or α-olefin content of 4 to 8 atoms carbon or a combination thereof in (ii) + (iii) is less than 50 percent; and (c) a thermoplastic olefin consisting essentially of: (i) from 10 percent to 60 percent of a propylene homopolymer having an isotactic index greater than 90, or a crystalline propylene copolymer with ethylene and / or an α-olefin of 4 to 8 carbon atoms having a propylene content greater than 85 percent and an isotactic index greater than 85 percent; (ii) from 30 percent to 60 percent of a fraction of the amorphous ethylene / propylene copolymer, optionally containing 0.5 percent to 10 percent of a diene, which is soluble in xylene at room temperature, and which contains 40 percent to 70 percent etiieno; and (iii) from 8 percent to 40 percent of a semi-crystalline ethylene / propylene copolymer that is insoluble in xylene at room temperature.

The process of claim 8, wherein the propylene polymer material is a propylene homopolymer.

11. The process of claim 8, wherein the methyl methacrylate copolymer is a copolymer of methyl methacrylate and methyl acrylate. The process of claim 8, wherein the hydroxylamine compound is a bis (hydrogenated tallow alkyl) oxidized amine. The process of claim 8, wherein the polymeric material further comprises a polyolefin rubber and a polypropylene material of broad molecular weight distribution having an Mw / Mn of 8 to 60, a melt flow rate of 0.5. at 50 grams per 10 minutes, and insoluble xylene at 25 ° C of more than or equal to 94 percent.