MXPA98008878A - Polyamide stable to light and termicame - Google Patents

Abstract

A light-stable and thermally stable polyamide having integrated stabilizers is prepared by polymerizing the polyamide-forming monomers in the presence of an effective amount of at least one hindered piperidine compound and at least one aliphatic dicarboxylic acid chain regulating compound.

Description

"POLYAMIDE STABLE TO LIGHT AND THERMALLY" FIELD OF THE INVENTION This invention relates to a polyamide that achieves great stability to light and heat. More particularly, this invention relates to a modified nylon polymer containing a hindered piperidine compound and a chain regulator, wherein the modified nylon polymer has improved stability to light and heat.

BACKGROUND OF THE INVENTION It is known that when nylon alone is exposed to light and / or heat, nylon becomes discolored and loses its physical properties such as retention of resistance and resistance to elongation. Therefore, the addition of light and / or heat stabilizer to the nylon is necessary in some cases, in order for the nylon to achieve acceptable performance. The stabilizers can be added before, during or after the polymerization. Conventional stabilizers are mixed with the polymer and are not bound to the polymer chain; therefore, during the processing or use of the polyamide, the stabilizers can easily migrate out of the polymer, evaporate and wash out. This means that the activity of the stabilization is reduced in an undesired way, and that the impurities are released into the environment (e.g., air, dye bath, etc.). Various organic stabilizers are known for use with nylon and articles made thereof. A problem, however, is that organic stabilizers, such as hindered phenols, are expensive and have limited effectiveness. Inorganic stabilizers are usually less expensive and more effective than organic stabilizers; however, inorganic stabilizers suffer from a different set of problems. Typically, common inorganic stabilizers, such as, for example, copper compounds, cause problems during processing. For example, in the melt extrusion process, copper compounds can be reduced to insoluble elemental copper. The formation of copper metal reduces the production efficiency and adds significantly to the maintenance costs of the equipment. In addition, the removal of copper deposits generates an environmentally undesirable effluent. In other processes such as, for example, the treatment of automotive nylon fibers with copper complexes in a dye bath, the excess copper complexes in the bath also produce in environmentally undesirable effluent. The commonly owned application of the North American Patent Serial Number 08 / 804,312 relates to a process for preparing stained, photochemically stable nylon compositions which comprises providing a dye bath with an article formed of poly (epsilon-caprolactam) polymerized hydrolytically in the presence of water and a hindered piperidine derivative and, in the dyebath, dyeing the shaped article with one or more metallized or non-metallized acid coloring matters. U.S. Patent Application Serial No. Serial No. 60 / 045,269 relates to a process for producing fibers dyed with a stabilized solution by melting a polyamide comprising amide monomers polymerized in the presence of at least one hindered piperidine compound and coloring the polyamide fused with a dye. PCT / EP95 / 01349, describes an inherently stabilized polyamide containing at least one triacetone diamine compound having a primary amino group (-NH) which reacts with a carboxy end group of the polyamide molecule during the polymerization, yielding therefore light and heat stable to the polymer.

An essay in Poly. SDR. And Stab. 21, 251-262 (1988) describes the improvement of the light stability of polyamide 6/6 by the addition of 2,2,6,6-tetramethylpiperidin-4-ol ("TMP"). In a nditioning of polyamide 6/6 containing TMP in the melt at 275 ° C under an atmosphere of water vapor, the authors claim that TMP reacts with the carboxyl end groups of the polyamide. There is therefore a need for a modified polyamide that reduces the need for copper-based stabilizers and that prevents discoloration, ie, yellowing after exposure to light and / or heat. In addition, it would be desirable to produce a polyamide that has improved resistance to yellowing during exposure to light and / or heat, especially in industrial plastic applications.

EXHIBITION DIGEST An object of the present invention is to provide a modified polyamide which prevents discoloration after exposure to light and / or heat.

Another object of the present invention is to reduce the need for copper-based stabilizers in polyamides. Still another object of the present invention is to provide an environmentally friendly and efficient process for producing a modified polyamide that is stable to both light and heat. Therefore, in accordance with one embodiment of the present invention, there is provided a method for producing a light-stable and thermally stable polyamide with integrated stabilizers. The method comprises subjecting one or more polyamide-forming monomers to a polymerization process in the presence of an effective amount of at least one hindered piperidine compound, and an effective amount of at least one aliphatic dicarboxylic acid chain regulating compound. . In another aspect, the present invention is directed to a light-stable and thermally stable polyamide comprising a polymer chain in the basic structure, at least one hindered piperidine radical, and at least one aliphatic dicarboxylic acid chain regulating compound. , wherein at least one hindered piperidine radical and at least one aliphatic dicarboxylic acid chain regulating compound are bonded to the polymer chain of the basic structure.

The polyamide of the present invention is essentially free of copper compounds. Modified polyamide with integrated stabilizers produced in accordance with the present invention achieves good light and heat stability without the use of other stabilizers such as such as copper salts. The combination of at least one aliphatic dicarboxylic acid chain regulating compound and at least one hindered piperidine compound not only functions as a molecular weight regulator in the polymerization process, but also gives the resultant polyamide stability of light and heat The modified polyamide of the present invention does not discolour at the early stage of exposure to ultraviolet light. The foregoing objects and others, effects, features and advantages of the present invention, will become more apparent from the following detailed description of the preferred embodiments thereof, particularly when viewed in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a graph - illustrating the percentage of retained strength for yarns dyed by solution after being exposed to an atmospheric conditions meter. Figure 2 is a graph illustrating the yellowing of the polymer plates after being exposed to an atmospheric conditions meter.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES In order to promote an understanding of the principles of the present invention, descriptions of the specific embodiments of the invention are presented below, and specific language is used to describe them. However, it will be understood that it is not intended to limit the scope of the invention through the use of this specific language and that the alterations, modifications, equivalents and additional requests of the principles of the invention discussed are proposed as would normally occur to a person. Knowing the technique to which the invention relates. As used herein, the term "polyamide" represents homopolymers, copolymers, blends and grafts of those long chain polymers having recurring amide groups (-CO-NH-) as an integral part of the main polymer chain. These long chain polyamides are generally called "nylons". As used herein with respect to the polyamide of this invention, the term "integrated" means that the components that make the polyamide stable to light and heat are chemically bonded to the polymer chain of the basic structure of the polyamide. the polyamide, instead of being only physically mixed with the polyamide. In one embodiment, the present invention is a modified polyamide substantially free of copper compounds comprising a polymer chain of the basic structure, at least one radical hindered piperidine and at least one compound of regulating chain aliphatic dicarboxylic acid , wherein at least one hindered piperidine radical and at least one aliphatic dicarboxylic acid chain regulating compound can be chemically linked to the polymer chain of the basic structure. The light-stable and thermally stable polyamide of the present invention can be nylon 6, nylon 6/6, nylon 6/9, nylon 6/10, nylon 6T, nylon 6/12, nylon 4/6, nylon 11, nylon 12 , or aromatic nylons such as for example, poly (of phenylene meta-isophthalamide) and poly (phenylene para-terephthalamide). Preferably, the uz and thermally stable polyamide of this invention is nylon 6, nylon 6/6, nylon 6T, nylon 6/12, and nylon 4/6. Particularly preferably, the light-stable and thermally stable polyamide in the present invention is nylon 6. Any of the appropriate polyamide-forming monomers can be used to form the light-stable and thermally stable polyamide of the present invention. Non-limiting examples of these suitable polyamide-forming monomers are diamine compounds, dicarboxylic acids, caprolactam monomers, and combinations thereof. In a preferred embodiment of the present invention, the polyamide-forming monomers are composed of caprolactam monomers. The polymerization process by which the polyamide of the present invention preferably is formed is carried out according to conventional processes such as for example those described in US Patent Number 5,149,758 issued to Matthies, the entirety of which is has been incorporated herein by reference, except that the polymerization of the present invention is carried out in the presence of an effective amount of one or more hindered piperidine compounds and an effective amount of one or more chain regulating compounds of aliphatic dicarboxylic acid. An effective amount of at least one hindered piperidine compound is a sufficient amount in combination with one or more chain-regulating compounds of the aliphatic dicarboxylic acid to be the resulting polyamide, light-stable and thermally stable. Preferably, the effective amount of one or more of the hindered piperidine compounds is within the range of about 0.030 percent to about 0.800 percent, and especially preferably of about 0.060 percent to about 0.400 mole percent, based on in weight of the polyamide-forming monomers used. An effective amount of at least one aliphatic dicarboxylic acid chain regulating compound is a sufficient amount in combination with one or more hindered piperidine compounds to render the resulting polyamide light and thermally stable. Preferably, the effective amount of one or more compounds of regulating chain aliphatic dicarboxylic acid is within the range of about 0.001 percent to about 0.800 and most preferably from about 0.050 percent to about 0500 mole percent, based on the weight of the polyamide-forming monomers used. To produce the polyamide of the present invention, one or more of the compounds and hindered amine one or more of the compounds of regulating chain aliphatic dicarboxylic acid is added to the starting monomers or polymerization reaction mixture. In this manner, one or more of the hindered piperidine compounds, one or more of the aliphatic dicarboxylic acid chain regulating compounds and the polyamide forming monomers can be added separately or as a mixture to a reactor., in which the polymerization is carried out. The hindered piperidine compound used in the present invention is represented by the formula: wherein Ri comprises an amine or amide-forming functional group, R2 is an alkyl, and R3 is selected from the group consisting of hydrogen, alkyl groups of 1 to 3 carbon atoms, and -OR4 wherein R4 is selected from group consisting of hydrogen, methyl, and alkyl groups of 1 to 7 carbon atoms. Ri is preferably selected from the group consisting of -NHR5 wherein Rs is hydrogen or an alkyl, carboxyl, carboxylic acid derivative of 1 to 8 carbon atoms, - (CH2) x (NH) Rs where x is an integer from 1 to about 6, - (CH2) and C00H wherein y is an integer from 1 to about 6, and an acid derivative - (CH) 2) and COOH. The hindered piperidine compound used in the present invention is preferably an amino polyalkylpiperidine or a polyalkylpiperidine acid. Non-limiting examples of these hindered piperidine compounds include: 4-amino-2,2,6,6-tetramethylpiperidine; 4- (Aminoalkyl (-2,2,6,6-tetramethylpiperdine; 4- (aminoaryl) -2,6,6-tetramethylpiperidine; 4- (aminoaryl / alkyl) -2,2,6,6-tetramethylpiperidine; 3-amino-2, 2,6,6,6-tetramethylpiperidine; 3- (aminoalkyl) -2,6,6-tetramethylpiperidine; 3- (aminoaryl) -2,2,6,6-tetramethylpiperidine; 3- (aminoaryl) / alkyl) -2,2,6,6-tetramethylpiperidine, 2, 2,6,6,6-tetramethyl-4-piperidinecarboxylic acid; 2,2,6,6-tetramethyl-4-piperidinalkylcarboxylic acid; 2,2,6,6-tetramethyl-4-piperidinarylcarboxylic acid; 2,2,6,6-tetramethyl-4-piperidinalkyl / arylcarboxylic acid; 2, 2, 6, 6-tetramethyl-3-piperidinecarboxylic acid; 2,2,6,6-tetramethyl-3-piperidinalkyl carboxylic acid; 2, 2, 6, 6-tetramethyl-3-piperidinarylcarboxylic acid; and 2,2,6,6-tetramethyl-3,4-piperidinalkyl / arylcarboxylic acid. The hindered amine compound can be a mixture of hindered piperidine compounds as well. Particularly preferably, the hindered piperidine compound is a 2, 2, 6, 6-tetraalkylpiperidine. Particularly preferably, the hindered piperidine compound is 4-amino-2,2,6,6-tetramethylpiperidine. Suitable chain regulating compounds for use in the present invention are aliphatic dicarboxylic acids and combinations thereof. Non-limiting examples of these aliphatic dicarboxylic acids include the following: malic acid; malonic acid; methylmalonic acid; ethylmalonic acid; Butylmalonic acid; dimethylmalonic acid; succinic acid; Methylsuccinic acid; 2, 2-dimethylsuccinic acid; 2,3-dimethylsuccinic acid; 2-ethyl-2-methylsuccinic acid; glutaric acid; 2, 2-dimethylglutaric acid; 2,3-dimethylglutaric acid; 2,4-dimethylglutaric acid; adipic acid; 3-methyladipic acid; azelaic acid; pimelic acid; sebacic acid; decandicarboxylic acid; and dodecandioic acid. The chain-regulating compound of the aliphatic dicarboxylic acid used in the present invention may be the same as or different from the dicarboxylic acid which is used of the polyamide-forming compound. The chain regulating compound of the aliphatic dicarboxylic acid is preferably selected from the group consisting of alkane dicarboxylic acids of 4 to 10 carbon atoms, particularly adipic acid, azelaic acid, sebacic acid and decandicarboxylic acid. Particularly preferably, the chain-regulating compound of the aliphatic dicarboxylic acid is adipic acid. Of course, various non-stabilizing additives may be used in the modified polyamide of the present invention. These include, for example, without limitation, lubricants, nucleating agents, antioxidants, antistatic agents, etc. The present invention produces a modified polyamide which is stabilized from degradation by light and heat and which does not discolor, ie, it acquires a yellow color upon exposure to light and / or heat. In the present invention it is not necessary to use other stabilizers such as for example copper compounds as additives, although other stabilizers may be present, if desired. If these other stabilizers are present, they are present in significantly reduced amounts. The elimination of these stabilization additives reduces the maintenance costs of the equipment and eliminates the harmful effluents produced in the removal of stabilizer deposits. The present invention also produces a modified polyamide having increased spinning efficiency. The spinning efficiency is increased by at least about 0.5 percent. This increase in insulation efficiency translates into hundreds of thousands of pesos in reduced annual manufacturing costs. While not wishing to be bound by any theory, it is usually believed that the increased spinning efficiency results from the fact that the modified polyamide of the present invention has a more critical molecular weight distribution than the polyamides regulated by acetic acid and propionic acid . For polymers having a relative viscosity of 2.7, the molecular weight distribution of the modified polyamide of the present invention is from about 1.65 to about 1.80, and the molecular weight distribution of the polyamides regulated by acetic acid and propionic acid is about 1.90 to approximately 2.00. The present invention is further directed to articles produced from light-stable and thermally stable polyamide of the present invention and to the methods for producing these articles. Non-limiting examples of these articles include fibers, yarns, binders, industrial plastics such as automotive parts and the like. The fibers can be formed by subjecting the light-stable and thermally stable polyamides of the present invention to any conventional fiber-forming process such as, for example, those disclosed in U.S. Patent Nos. 4,983,448 to Karageorgiou and 5,487,860 to Kent et al. , the totality of both of which is incorporated herein by reference. Preferably, the fiber forming process involves rapidly spinning the light-stable and thermally stable polyamide at speeds of at least about 4,000 meters per minute. The industrial plastics can be formed by subjecting the light and thermally stable polyamides of the present invention to any conventional plastic forming process such as for example that disclosed in Patent Number 5,474,853 issued to atanabe and others, all of which is incorporated herein by reference. The fibers formed of the light-stable and thermally stable polyamides of the present invention can be dyed with conventional dyes used for dyeing nylon such as, for example, metallized and non-metallized acid dyes. The usual dye bath conditions for dyeing nylon can be used. The following general conditions are exemplary and are not intended to be limiting. A dye bath is prepared at a volume equal to approximately 20 times the weight of the articles to be dyed. The processing chemicals are added including a chelating agent to prevent the deposition or formation of metal ions complex in hard water, a coloring leveling agent and in the case of metallized acid dyes, an acid donor to decrease slowly the pH of the coloring bath. The coloring matter is added, and the pH of the coloring bath is adjusted. The solution is heated to the desired temperature typically from about 95 ° C to about 110 ° C at a rate of about 0.5 ° C to about 3.0 ° C per minute and is maintained at that temperature for about 30 minutes to about 60 minutes . The coloring bath is cooled or emptied, and the articles are rinsed vigorously with fresh water. The dyed articles are dried in a drum dryer or an oven such as a Tenter oven. Alternatively, the fibers produced from the light-stable and thermally stable polyamides of the present invention can be dyed by solution before being formed into articles. The usual conditions can be used to dye the nylon solution. The following general conditions are exemplary and are not intended to be limiting. The polyamide of the present invention is melted and colored with a colorant which is selected from the group consisting of pigments, dyes and a colored compound with properties between pigments and dyes, and combinations thereof. The colored polyamide is then spun into fibers or cloth according to conventional methods such as for example those disclosed in U.S. Patent No. 4,983,448 issued to Karageorgiou, U.S. Patent Number 5,487,860 issued to Kent et al., And U.S. Patent Number 4,918,947. granted to Speich. For industrial plastics, the polymer chips are mixed with colored compounds such as for example pigments and dyes, before being loaded in an extrusion apparatus. Mixing before loading into the extrusion apparatus is a physical mixture, not a fusion mixture. The invention will be further described with reference to the following detailed examples. The examples are indicated by way of illustration and are not intended to limit the scope of the invention. In the examples "ADA" refers to adipic acid, "PPA" refers to propionic acid, "TPA" refers to terephthalic acid, and "TAD" refers to 4-amino-2, 2,6,6-tetramethylpiperidine. . The following test terms and conditions are also used in the examples, which are defined as follows: Percentage in Weight The percentage by weight of that component in the load.

Relative Viscosity (RV) Relative viscosity compares the viscosity of a polymer solution in formic acid with the viscosity of formic acid itself (Method D 789 of the American Society for the Testing of Materials). The results of the test disclosed herein were obtained using 0.20 gram of nylon 6 dissolved in 20 cubic centimeters of formic acid at 25 ° C.

Final Group Content The content of the final amino group is determined by dissolving approximately 2.0 grams of the polymer in approximately 60 cubic centimeters of a phenol-methanol mixture (68:32). This solution is evaluated with approximately 0.20 normal HCl at a temperature of approximately 25 ° C by the potentiometric method where the end point is determined by an increase in excessive potential. The content of the final carboxy group is determined by dissolving about 0.30 gram of the polymer in about 40 cubic centimeters of a benzyl alcohol mixture at 180 ° C. The solution is evaluated with approximately 0.03 normal t-butyl ammonium hydroxide at a temperature of about 80 ° C to about 100 ° C by a potentiometric method, where the end point is determined by an excessive potential increase.

Exposure Testing This test is designed to simulate extreme environmental conditions found within a vehicle due to sunlight, heat and humidity for the purpose of predicting the performance of automotive interior materials. This test measures the amount of yellowing (the delta b * value) of each of the exposed samples. This test is carried out in accordance with the GM SAE Test Method J1885 which is called "Accelerated Exposure of Automotive Interior Trim Components using a Controlled Irradiance Water-Cooled Xenon-Arc Apparatus".

Resistance retention This test is designed to determine the retention of the resistance of the controls and the experimental samples. The term "resistance retention" refers to the change in the tenacity of the material as a result of the exposure of the material to sunlight or an artificial light source. Tenacity is a measure of the strength of the fiber. This test is carried out in accordance with AATCC Test Method 16-1993, Color Light Resistance, Option E (Water Cooled Xenon Arc Lamp, Continuous Light). The materials are exposed to 2125 KJ of exposure, and the tenacity of each material is measured before exposure and after each exposure increase of 425 KJ. The percentage of resistance retention is determined as follows: Tenacity after exposure x 100% Tenacity before exposure EXAMPLE 1 (Comparison) Polymerization of Nylon 6 Regulated with PPA / TAD A mixture of 75 kilograms of caprolactam, 1800 grams of water, 135 grams (0.18 weight percent) of propionic acid and 112.5 grams (0.15 weight percent) of 4-amino-2,2,6,6-tetramethylpiperidine is loaded in a 250-liter capacity autoclave. The mixture was heated to 270 ° C in one hour while the pressure increased to 4,218 kilograms per square centimeter (3102 millimeters of mercury). After retaining the mixture at 4,218 kilograms per square centimeter for 30 minutes, the pressure is released slowly. To accelerate the polymerization, the system is placed in a vacuum of 400 millimeters of mercury for 75 minutes. The polymer is then extruded under positive nitrogen pressure and cut into chips. The chips are washed with hot water (90 ° C) and dried in a drum dryer. The relative viscosity measures 2.71. The content of the amino group measures 42 milliequivalents per kilogram and the content of the final carboxylic group measures 45 milliequivalents per kilogram.

EXAMPLE 2 Polymerization of Nylon 6 Regulated with ADA / TAD A mixture of 75 kilograms of caprolactam, 1800 grams of water, 240 grams (0.32 weight percent) of adipic acid, and 112.5 grams (0.15 weight percent) of 4-amino-2, 2, 6, 6 is charged. -tetramethylpiperidine in an autoclave with a capacity of 250 liters. The mixture is heated to 270 ° C in one hour, while the pressure increases to 4,218 kilograms per square centimeter (3102 millimeters of mercury). After retaining the mixture at 4,218 kilograms per square centimeter for 30 minutes, the pressure is released slowly. To accelerate the polymerization, the system is placed in a vacuum of 500 millimeters of mercury for 45 minutes. The polymer is then extruded under positive nitrogen pressure and cut into chips. The chips are washed with hot water (90 ° C) and dried in a tumble dryer. The relative viscosity measures 2.67. The amino group content measured 37 milliequivamentes per kilogram, and the content of the carboxyl final group measured 70 milliequivalents per kilogram.

EXAMPLES 3 (Comparison) Polymerization of Nylon 6 Regulated with PPA / 0.15 percent of TAD A molten caprolactam mixture containing 0.5 weight percent water and 0.19 weight percent propionic acid is continuously introduced into the top of a polymerization reactor. The polymerization reactor used is a stainless steel VK column as noted in U.S. Patent No. 4,354,020, which is incorporated herein by reference. The mixture is continuously introduced at the top of the VK column into the reaction zone 1 at a temperature of about 265 ° C and at a rate of about 30 to 40 kilograms per hour, with stirring. The VK column, which has a capacity of 340 liters, is heated by heat exchange oil. At the same time 4-amino-2, 2, 6,6-6-tetramethylpiperidine is continuously supplied from a separate stream to the reaction zone I so that there is 0.15 weight percent of 4-amino-2, 2, 6 , 6-tetramethylpiperidine in the mixture at all times. The heat of the polymerization generated in the additional reaction zones is removed by appropriate cooling with internal heat exchangers. The temperature of the last reaction zone is about 265 ° C. The resulting polymer is extruded at the bottom of the VK column and cut into chips. The chips are washed with hot water (90 ° C) and dried in a tumble dryer. The relative viscosity measures 2.68. Both the content of the amino group and the content of the carboxyl end group measure 44 milliequivalents per kilogram.

EXAMPLE 4 Polymerization of Nylon 6 Regulated with ADA / 0.15 percent of TAD The caprolactam is polymerized in the same column VK as in Example 3, but with the addition of 0.29 weight percent adipic acid, 0.5 weight percent water, and 0.15 weight percent 4-amino-2,2,6,6-tetramethylpiperidine. The dried product has a relative viscosity of 2.73, a final amino group content of 43 milliequivalents per kilogram, and a final carboxylic group content of 59 milliequivalents per kilogram.

EXAMPLE 5 Polymerization of Nylon 6 Regulated with ADA / O.30 percent TAD Caprolactam polymerizes in the same column VK as in Example 3, but with the addition of 0.29 percent adipic acid, 0.5 percent water, and 0.30 percent by weight of 4-amino-2,2,6,6-tetramethylpiperidine. The dry product has a relative viscosity of 2.70, a final amino group content of 53 milliequivalents per kilogram, and a final carboxylic group content of 51 milliequivalents per kilogram.

EXAMPLE 6 (Comparison) Polymerization of Nylon 6 of TPA / 0.15% of TAD The cxaprolactam was polymerized with the same VK column as in Example 3 with the addition of 0.30 weight percent terephthalic acid, 0.5 weight percent water, and 0.15 weight percent 4-amino-2, 2, 6,6-tetramethylpiperidine. The dried product had a relative viscosity of 2.68, a content of the final amino group of 42 milliequivalents per kilogram, and a content of the carboxyl end group of 63 milliequivalents per kilogram.

EXAMPLE 7 Thread Yarn Stained by 1115 Denier Solution / 58 Filaments with Trilobal Cross Section The nylon polymer 6 of Examples 3 to 6, as well as commercial nylon 6 (nylon 6 Ultramid B® obtainable from BASF Corporation of Mount Olive, NJ), is extruded at temperatures of 260 ° C to 265 ° C. The opal gray concentrate mixed with an appropriate amount of the nylon chip is added to the spinning machine through volumetric feeders. The extruded filaments are cooled and solidified by a rapid cooling air stream at 15 ° C. After application of the spin finish, the yarns are drawn at a draw ratio of 3.3 and are textured in a texture jet at 215 ° C. The yarns are collected at a pick roller speed of approximately 2350 meters per minute.

EXAMPLE 8 Retention of Resistance after Exposure to Ultraviolet Rays The yarns dyed with opal gray solution of Example 7 is exposed on an Atlas Ci65 * Atmospheric Conditions Meter for 2125 kJ of exposure in 425 kJ increments under the conditions specified by Test Method AATCC 16-1993, Color Resistance to Light, Option E. The resistance of each of the threads is measured before exposure and after each increment of 425 kJ of exposure. The percentage of retention of resistance after each increment of exposure is shown in Figure 1. These results show a significant improvement in the retained strength for the polymers containing TAD, especially the ADA / TAD polymers. Commercial nylon 6 lost its strength dramatically during exposure, while polymers containing TAD retained more than 85 percent of their strength after 2125 kJ of exposure.

EXAMPLE 9 Yellowing of the Plates By GM SAE Test Method J1885 The polymers of Examples 3 to 6 as well as commercial nylon 6 (nylon 6 Ultramid B® obtainable from BASF Corporation of Mount Olive, NJ), are melted in a injection molding machine at a temperature of approximately 265 ° C. The molten polymer is injected into a mold to produce plates of 110 millimeters by 110 millimeters by 3 millimeters. These plates are then cut into smaller plates each measuring about 55 millimeters by 110 millimeters by 3 millimeters. The plates are then exposed in a Meter of Atlas Ci65 Xenon-Arc Atmospheric Conditions for 1, 000 hours (1,410 kJ) in increments of 100 hours (141 kJ) by the conditions specified in Test Method GM SAE J1885. The exposed plates are measured to determine yellowing (or "Delta b *," where a higher Delta b * value indicates a yellower sample) during each exposure increment using an Applied Color Systems Spectrophotometer. The results of these exposures are plotted in Figure 2. The results show that the commercial nylon 6 polymer and the regular comparison polymer with TPA / 0.15 percent of the TAD acquired a yellowish color very significantly during exposure. Even though the exposure of the PPA / TAD polymer resulted in less yellowing than the commercial nylon 6 polymer and the comparison polymer regulated with TPA / 0.15 percent TAD, the exposure of the ADA / TAD polymers resulted in only a minimum yellowing Even though the invention has been described in relation to what is currently considered to be the most practical and preferred modality, it will be understood that the invention should not be limited to the modality disclosed, but on the contrary it is intended to protect the different modifications and equivalent provisions included within the spirit and scope of the appended claims.

Claims (22)

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

1. A method for producing a light-stable and thermally polyamide comprising subjecting one or more polyamide-forming monomers to a polymerization process in the presence of an effective amount of at least one hindered piperidine compound and an effective amount of minus a chain regulator compound, wherein at least one chain regulator compound comprises an aliphatic dicarboxylic acid and combinations thereof.

2. The method according to claim 1, wherein at least one hindered piperidine compound is selected from the group consisting of amino-polyalkylpiperidines.

3. The method according to claim 1, wherein at least one hindered piperidine compound is selected from the group consisting of 4-amino-2, 2,6,6-tetramethylpiperidine; 4- (aminoalkyl) -2, 2,6,6,6-tetramethylpiperidine; 4- (aminoaryl) -2,6,6,6-tetramethylpiperidine; 4- (aminoaryl / alkyl) -2,6,6,6-tetramethylpiperidine; 3-amino-2, 2, 6, 6-tetramethylpiperidine; 3- (aminoalkyl) -2, 2,6,6,6-tetramethylpiperidine; 3- (aminoaryl) -2, 2,6,6,6-tetramethylpiperidine; 3- (aminoaryl / alkyl) -2, 2,6,6,6-tetramethylpiperidine; 2, 2, 6, 6-tetramethyl-4-piperidinecarboxylic acid; 2,2,6,6-tetramethyl-4-piperidinalkylcarboxylic acid; 2,2,6,6-tetramethyl-4-piperidinarylcarboxylic acid; 2,2,6,6-tetramethyl-4-piperidinalkyl / arylcarboxylic acid, 2,2,6,6-tetramethyl-3-piperidinecarboxylic acid; 2,2,6,6-tetramethyl-3-piperidinalkylcarboxylic acid; 2,2,6,6-tetramethyl-3-piperidinarylcarboxylic acid; 2,2,6,6-tetramethyl-3,4-piperidinalkyl / arylcarboxylic acid; and combinations thereof.

4. The method according to claim 3, wherein at least one hindered piperidine compound is 4-amino-2, 2,6,6-tetramethylpiperidine.

The method according to claim 1, wherein at least one aliphatic dicarboxylic acid chain regulating compound is selected from the group consisting of malic acid; malonic acid; methylmalonic acid; ethylmalonic acid; Butylmalonic acid; dimethylmalonic acid; succinic acid; Methylsuccinic acid; 2, 2, -dimethylsuccinic acid; 2,3-dimethylsuccinic acid; 2-ethyl-2-methylsuccinic acid; glutaric acid; 2, 2-dimethylglutaric acid; 2,3-dimethylglutaric acid; 2,4-dimethylglutaric acid; adipic acid; 3-methyladipic acid; azelaic acid; pimelic acid; sebacic acid; decandicarboxylic acid; dodecandioic acid; and combinations thereof.

The method according to claim 5, wherein at least one aliphatic dicarboxylic acid chain regulating compound is selected from the group consisting of adipic acid, azelaic acid, decandicarboxylic acid, sebacic acid and combinations thereof.

The method according to claim 6, wherein at least one aliphatic dicarboxylic acid chain regulating compound is adipic acid.

The method according to claim 1, wherein the light-stable and thermally stable polyamide is selected from the group consisting of nylon 6, nylon 6/6, nylon 6/9, nylon 6/10, nylon 6T, nylon 6/12, nylon 4/6, nylon 11, nylon 12, poly (meta-phenylene isophthalamide), and poly (para-phenylene terephthalamide).

The method according to claim 8, wherein the light-stable and thermally stable polyamide is nylon 6.

The method according to claim 1, wherein the polyamide-forming monomers comprise caprolactam monomers.

11. A light-stable and thermally stable polyamide comprising a polymer chain of basic structure, at least one hindered piperidine radical, and at least one aliphatic dicarboxylic acid chain regulating compound wherein both at least one radical hindered piperidine and at least one aliphatic dicarboxylic acid chain regulating compound are chemically bonded to the polymer chain of the basic structure.

The polyamide according to claim 11, wherein at least one hindered piperidine compound is selected from the group consisting of amino-polyalkylpiperidines.

The polyamide according to claim 11, wherein a hindered piperidine compound is selected from the group consisting of 4-amino-2, 2,6,6-tetramethylpiperidine; 4- (aminoalkyl) -2,2,6,6-tetramethylpiperidine; 4- (aminoaryl) -2,6,6,6-tetramethylpiperidine; 4- (aminoaryl / alkyl) -2,2,6,6-tetramethylpiperidine; 3-amino-2, 2, 6, 6-tetramethylpiperidine; 3- (aminoalkyl) -2,2,6,6-tetramethylpiperidine; 3- (aminoaryl) -2, 2,6,6,6-tetramethylpiperidine; 3- (aminoaryl / alkyl) -2,2,6,6-tetramethylpiperidine; 2, 2, 6, 6-tetramethyl-4-piperidinecarboxylic acid; 2,2,6,6-tetramethyl-4-piperidinalkylcarboxylic acid; 2,2,6,6-tetramethyl-4-piperidinarylcarboxylic acid; 2,2,6,6-tetramethyl-4-piperidinalkyl / arylcarboxylic acid, acid 2, 2, 6, 6-tetramethyl-3-piperidinecarboxylic acid; 2,2,6,6-tetramethyl-3-piperidinalkylcarboxylic acid; 2,2,6,6-tetramethyl-3-piperidinarylcarboxylic acid; 2,2,6,6-tetramethyl-3,4-piperidinalkyl / arylcarboxylic acid; and combinations thereof.

The polyamide according to claim 13, wherein at least one hindered piperidine compound is 4-amino-2,2,6,6-tetramethylpiperidine.

15. The polyamide according to claim 11, wherein at least one aliphatic dicarboxylic acid chain regulating compound is selected from the group consisting of malic acid; malonic acid; methylmalonic acid; ethylmalonic acid, butyl allylic acid; dimethylmalonic acid; succinic acid; Methylsuccinic acid; 2, 2, -dimethylsuccinic acid; 2,3-dimethylsuccinic acid; 2-ethyl-2-methylsuccinic acid; glutaric acid; 2, 2-dimethylglutaric acid; 2,3-dimethylglutaric acid; 2,4-dimethylglutaric acid; adipic acid; 3-methyladipic acid; azelaic acid; pimelic acid; sebasic acid; decandicarboxylic acid; dodecandioic acid; and combinations thereof.

16. The method according to claim 15, wherein at least one aliphatic dicarboxylic acid chain regulating compound is selected from the group consisting of adipic acid, azelaic acid, decandicarboxylic acid, sebacic acid and combinations thereof.

17. The method according to claim 16, wherein at least one aliphatic dicarboxylic acid chain regulating compound is adipic acid.

18. The polyamide according to claim 11, wherein the polyamide is selected from the group consisting of nylon 6, nylon 6/6, nylon 6/9, nylon 6/10, nylon 6T, nylon 6/12, nylon 4 / 6, nylon 11, nylon 12, poly (meta-phenylene isophthalamide), and poly (para-phenylene terephthalamide).

19. The polyamide according to claim 18, wherein the polyamide is nylon 6.

20. A light-stable and thermally stable polyamide comprising a polymer chain of basic structure, at least one impeded piperidine radical chemically bonded to the polymer chain of the basic structure, and at least one aliphatic dicarboxylic acid chain regulating compound chemically bonded to the polymer chain of the basic structure, wherein the spinning efficiency of the polyamide stable to light and thermally it is increased by at least 0.5 percent.

21. An article comprising the light-stable and thermally-stable polyamide according to claim 11.

22. An article of conformity with claim 21, wherein the article is selected from the group consisting of fibers, yarns, folders and plastics. industrial