MXPA97004245A - Policaprolact with a novel adjustment of your cad - Google Patents

Abstract

The present invention relates to the polyamide 6, hydrolytically polymerized and regulated chain, characterized in that the polymerization of caprolactam (I) is carried out with: -0.1-0.7 weight percent of an aromatic dicarboxylic acid ( II), -0.01-0.7 weight percent of an aliphatic or cycloaliphatic diamine (III) carrying a primary amino group and a tertiary amino group, and / or -0.01-0.7 weight percent of 4-amino-2, 2,6,6-tetraalkyl piperidine (IV), in which the amounts of the components from I to IV are added to form 100 percent by weight, and the amount of the components III and / or IV form from 0.01-0.7 percent of pe

Description

"POLICAPROLACTAMA WITH AN INNOVATIVE REGULATION OF YOUR CHAIN" BACKGROUND OF THE INVENTION The present invention is directed to the subject indicated in the clauses of the patent. More particularly, the invention is directed to a new and improved polycaprolactam (PA-6) with novel regulation of its chain. Low-to-medium-viscosity polycaprolactam (PA-6) for the production of compounds or fibers for injection molding is usually produced by the polymerization of caprolactam under the shared use of chain regulators, such as acetic acid or other monocarboxylic acids . The molecular weight of the PA-6 is thus established at the desired value and the stability of the viscosity of the PA-6 melt during processing is ensured at the same time. For PA-6 from low to medium viscosity the present refers to the extracted products, ie, products released mainly from caprolactam which has a relative viscosity of solution from about 1.65 to about 1.95, as measured in a solution of 0.5 of weight percentage in a m cresol at 20 ° C. In addition to requiring a high processing stability, the production of fibers requires a defined and constant concentration of a terminal amino group to ensure a good affinity to the dyeing. To achieve good results in the coloring with, for example, acidic dyes soluble in PA-6, the concentration of the terminal amino group in the fibers should ideally be 40-50 meq / kg. The conditions are different because of the modifications for the injection molding of PA-6 from low to medium viscosity in that there are a number of products that can be produced with good quality when only significantly lower concentrations of the terminal amino group are provided. 25-30 meq / kg of the PA-6 used. The following products or, respectively, groups of products are among those included among these PA-6 materials for injection molding: 1. Impact Resistant Mixtures of Polyolefin PA6 (Co) having a two-phase morphology and whose component of (co) polyolefin is grafted with unsaturated carboxylic acids or, respectively, carboxylic acid derivatives, or is chemically modified in some other way. Typical modifying agents are, for example, (meta) acrylic acid and the esters thereof or maleic anhydride. For example, copolymers of ethylene / p_propylene / (diene) (EPDM), low density polyethylene .Linear (LLDPE), or other types of polyethylene that are employed as (co) polyolefins. It is in fact recommended - for example, in Privilege Patent of the United States of North America No. 4,945,129 - to employ PA-6 with a comparatively high concentration of the NH 2 group for such mixtures; the possible gain in terms of impact resistance or, respectively, resistance to impact and grooves is then at the expense of injection molding processing. In particular, an ex-tension of the duration of each cycle and, therefore, an extension of productivity must be accepted when such materials are processed. In addition to this, problems arise from the pigmented materials provided, and these are expressed in the lack of uniformity when the pigment is dispersed on the surfaces of the finished parts. An acceptable balance of the properties mentioned above is only achieved by using PA-6 having a comparatively low concentration of the NH2 group (25-30 meq / kg). 2. PA-6 Flame Retardant that is modified with specific nitrogen compounds. For example, these products, which are added to the casting of PA-6 in the extruders, include melamine, melamine cyanurate, melamine phosphate and comparable materials. The combustion behavior of such mixtures is normally tested in the combustion test of the Underwri-ters Laboratories and is classified with the corresponding UL 94 standard. To achieve the best possible classification (VO), the quality of the PA-6 and the quality of the nitrogen compound retardant to the flames must be very well balanced between the two. An important characteristic of the quality of PA-6 is, therefore, the aforementioned amount of the concentration of the NH2 group. From the above comments it can be deduced that the demands made for PA-6 of low and medium viscosity for fiber manufacturing and injection molding purposes can not be met without treating the same product with respect to the concentration of the terminal amino group. No teaching is found in the patent literature and other relevant sources regarding how to make contrary demands of PA-6 made for fiber molding and by injection with a uniform product. BRIEF DESCRIPTION OF THE INVENTION The objective of the present invention is, therefore, to offer PA-6 of low and medium viscosity for purposes of fiber molding and injection that meets the demands made for both applications. The objective underlying this invention is achieved by providing the PA-6 with a novel chain regulator whose manufacture arises from hydrolytic polymerization, i.e. by water-induced deprotetion of caprolactam (I) together with: - 0.1-0.7 weight percent of an aromatic dicarboxylic acid (II) - 0.01-0.7 weight percent of an aliphatic or cycloaliphatic diamine (III) carrying a primary amino group and a tertiary amino group, and / or - 0.01-0.7 weight percent of the 4-amino 2,2,6,6-tetra-alkyl-piperidine (IV), in which the amounts of the components from I to IV are added to form 100 weight percent and the amount of components III and / or IV makes up 0.01 to 0.7 weight percent. Terephthalic acid and / or isophthalic acid are preferably used as dicarboxylic aromatic acids (II), preferably in an amount of 0.2-0.6 weight percent. The diamino III component is preferably selected from the group consisting of the 3- (dialkylamino) -1-propylamines, 2- (dialkylamino) -1-ethylamines, piperidonoalkylamines and pyrrolidinoalkylamines, and is preferably used. in an amount of 0.01-0.6 percent by weight. Examples of component III are 3- (dimethylamino) -1-propylamine and 2-piperidine-ethylamine. 4-Amino-2, 2, 6, 6-tetramethylpiperidine is preferred as the diamine component IV, and is used in an amount of 0.01-0.6 weight percent. The amount of the components III and / or IV of diamine constitute, preferably of 0.05-0.6 weight percent.

DETAILED DESCRIPTION OF THE INVENTION The manufacture of the inventive component PA-6 occurs according to continuous or batch methods that are well known for a long time. The relationships between the amount of the chain controller or regulator, the water content of the reaction mixture, and the handling of the temperature and reaction time on the one hand and the conversion of caprolactam as well as the molecular weight of the PA-6 produced, on the other hand, that are known and have been tested in industrial practice, need not be discussed here in greater detail. Specifically, given the continuous methods given to produce PA-6 in tubular reactors of vertical arrangement, there is adequate experience to allow the operators of these systems to convert their production of PA-6 to the production of PA-6 of the invention with its novel regulation of the chain without encountering significant problems. The batch production of the PA-6 of the invention can also be implemented without problems. It is understood then that PA-6 composed in this way yields considerable advantages for production; the frequency of product conversion can be reduced in this way. The manufacturer of PA-6 would like to limit the conversions of the product to the current conventional PA-6 polymerization systems - which are practically exclusively operated according to continuous methods and with yields of approximately 50-200 tons daily. - to a minimum as far as possible. Each conversion involves the production of what is known as transition material, which can arrive in quantity at several daily yields and which is difficult to coordinate with the existing specifications of the products. The inventive PA-6 with its chain regulation exhibits the desired properties as initially defined for the manufacture of fibers and specific injection molding applications. These properties are established in more detail in the examples. Polymerization of the PA-6 of the invention was carried out in the form of fillers in an autoclave of 130 liters capacity. To this end, 45 kg of liquid caprolactam at 90 ° C were mixed respectively together with 7 liters of water and the amounts of terephthalic acid and diamines indicated in Table 1, and placed in a stirrable vessel which had become inert. with nitrogen, and the homogeneous mixture was subsequently transferred into said autoclave and polymerized therein under inert conditions (N2). Approximately, the following uniform conditions were observed in the polymerization: Stage 1 Mass temperature: 290 ° C (Pressure phase: 20 bar pressure) Duration: 2 hours Stage 2 Mass temperature: from 290 to 260 ° C (relax- Pressure: from 20 to 1 bar) Duration: 1.5 hours Stage 3 Mass temperature: 260 ° C (degassing - Pressure: 1 bar) Trailed gas: Nitrogen Duration: 4-6 hours When the desired viscosity was reached, the in-dividual loads were pressed outward as polymer cords, were granulated after passing through a water bath, extracted with water and dried. The torsion indicator of the autoclave agitator formed the basis of the criteria for the viscosity of the PA-6 melt. 40 kg of each wash were extracted in 16 hours at 80 ° C with 2,400 liters of fresh water per hour. The drying was carried out in a vacuum for 24 hours at 110 ° C. The relative viscosity of the extracted and dried PA-6 solution was determined in a 0.5 weight percent solution in a cresol m at 20 ° C. The determination of the concentration of the terminal group was carried out by acidimetric titration. The terminal amino groups were titrated with 0.1% perchloric ethanolic acid in cresol m / isopropanol 2: 1 (parts by weight) as solvent. The titration of terminal carboxyl groups with 0.1 normal benzyl alcoholic potassium hydroxide was carried out in benzyl alcohol as a solvent. The following types of PA-6 extracted from the end chain with acetic acid were used as comparative materials: Fiber Type (No. 5) with a solvent relative viscosity of 1.78 and a concentration of carboxyl group or, respectively, amino terminal group of 56 or, respectively, 46 meq / kg; Type of Injection Molding (No. 6) with a relative viscosity of 1.77 and a concentration of carboxyl group or, respectively, amino terminal group of 57 or, respectively, 29 meq / kg. The abbreviations used in the examples have the following meanings: LC6 Caprolactam TPS Terephthalic acid DMAPA 3- (dimethylamino) -1-propylamine TMPA 4-amino-2, 2,6,6-tetramethyl piperidine PEA 2-piperidino ethylamine RV Relative viscosity of the solution (0.5 weight percent / m-cresol) COOH Concentration of carboxyl terminal group Amine Concentration of amino terminal group KSZ Resistance to impact and cracks (in the dry condition) Tk Cooling time Tz Cycle time These diamines were obtained of the company FLUKA (Buchs, Switzerland). EXAMPLES 1. Polymers In Table 1, reference is made to Examples la, Ib, 2a, 2b, 3 and 4.

Table 1: Characterization of the P-6 of the invention (extracted and dried) Raw Material RV COOH Amine11 (meq / kg) (meq / kg) Example LC-6 TPS DMAPA TMPA PEA (kg)% Weight ikg)% Weight (kg )% Weight: < g)% Weight (kg)% Weight the 45 99.436 0.20 0.442 0.055 0.122 1.765 78 42 ib 45 99436 0.20 0.442 0.055 0.122 1.753 79 45 10 2a 45 99.373 0.20 0.442 C.384 0.185 1.793 74 38 2b 45 99.373 0.20 0.442 0.084 0.185 1.774 76 42 45 99,405 0.20 0.442 0.069 0.153 1.755 77 43 45 99.403 0.20 0.442 0.028 0.062 C.042 0.093 1.763 79 44 1) The measured concentrations of the terminal amino group are apparently composed of the concentration of the primary amino groups (-NH) in all cases, tertiary amino groups ((CH3O2-N- in Example la) and Ib), or respectively , terminal piperidino groups in Example 3) and secondary amino groups (2, 2, 6, 6-tetramethyl-4-piperidyl radicals in the case of Examples 2a and 2b) In the case of Example 4, all types appear of terminal amino groups. twenty 2. Manufacture and Testing of Modified Compounds for Injection Molding 2.1 Flame Retardant Products 90 parts by weight of PA-6 are mixed with 10 parts by weight of fine particulate melamine cyanurate in a ZSK-30 extruder with propellers. twins (L / D = 42) from Werner & Pfleiderer (Stuttgart, Germany) at extruder temperatures of 240-250 ° C and a total yield of 9 kg / h in the melt (PA-6) is obtained. The PA-6 granulate is mixed dry with the melamine cyanurate before the combination step. After cooling the cords in a water bath, the finished mixture is granulated or formed into pellets and then vacuum dried for 24 hours at 110 ° C. The dry pellets are injection molded to form test rods of 127 x 12.7 x 0.8 (mm) and are subjected to the combustion test in accordance with the UL-94 standard. The results of these tests can be found in Table 2: Table 2: UL-94 test of melamine cyanurate / PA6 in 90/10 Mixtures Example PA-6 Used Result 5 of Example 3 V0 6 Fiber Type V2 (Example (No. 5) Comparative 7 Type of VO Molding (Example by Comparative Injection) (No. 6) The results demonstrate the PA-6 of the invention according to Example 3 as extremely suitable for this type of modification. 2. 2 Modified Impact Resistance Products 80 parts by weight of PA-6 together with 20 parts by weight of a grafted ethylene / propylene copolymer with 0.5 weight percent maleic anhydride (mol ratio of ethylene / propylene: 80 / 20; Mooney viscosity: 21 MLl + 4 at 125 ° C), and one part by weight of glycerin monostearate from the company AG Vogel (Zurich, Switzerland) as well as 0.63 parts by weight of Sachtolith HDS® white pigment from the company Sachtleben (Duisburg, Germany) and 0.05 parts by weight of black FW2 from Degussa (Baar, Switzerland) in a twin screw extruder (WPFZSK-30); L / D = 42). The temperature of the extruder reaches 250-260 ° C and the yield is 10 kg / hour. The mixtures were granulated and dried in the same manner as stated above for the flame retardant products. The pellets were then injection molded to form test pieces to measure impact resistance and crevices according to Charpy, in the dry condition; The test pieces were manufactured according to ISO-179 (rods 80 x 10 x 4 mm, mass temperature: 265 ° C, molding temperature: 80 ° C). To test their processability, these blends were processed to form a complicated part by means of injection molding with long ejection and core paths (part in the form of the company logo with sensitization of the rods and a weight of about 105 g. .). The full mass temperature was adjusted to 265 ° C, the molding temperature was constantly 80 ° C. The cooling time (including pressure stop time) required minimally to ensure perfect separation of the mold (without bulging, without deep markings of the apparatus on the parts) was measured in these processing tests. Additionally, the appearance of dark gray molded parts by injection was evaluated visually. The results can be found in Table 3 and confirm the advantageous properties of the polyamide 6 of the invention.

Table 3: Testing Modified Products in your Force in the face of Impact Example PA-6 Employee KSX (kJ / irf) Processing Test 23 ° -30"Appearance of injection molded parts (sec) (sec) of Example 4 70 15 85 96 perfect, uniform coloring Type Fiber (No.5) 33 17 95 107 non-uniform coloring, i.e.

.'Eje-.plo velos light gray / dark and comparative stains) 10 Type Molding by 75 15 33 95 perfect, uniform coloring i Example Injection (No. 6) comparative) 3. Fiber Fabrication and Stain Affinity Testing Individual types of PA-6 were spun in a spinning system: Yield: 1.5 g per minute and capillary Casting temperature: 262-264 ° C Wire cooling: cross flow fan Carriage speed: 4,200 m per minute In addition to the products of the invention the / b (the Examples la and Ib) and 2a / b (Examples 2a and 2b), respectively with granulated mixtures, the type of fiber (No. 5) and the type of injection molding (No. 6) were spun to make a comparison. The coffee stain of Irgalan 2RL (from Ciba Geigy, Ba-sel, Switzerland) yielded good results for 1 a / b, 2 a / b and the No. 5 comparison material and a moderate result for the No. 6 injection type by molding with respect to the depth and uniformity of the color.

Claims (6)

1. NOVELTY OF THE INVENTION Having described the invention, it is considered as a novelty and, therefore, the content of the following clauses is claimed as property. CLAUSES 1. Polyamide 6, hydrolitically polymerized and regulated chain, characterized in that the polymerization of caprolactam (I) is carried out with: - 0.1-0.7 weight percent of an aromatic di-carboxylic acid (II) , - 0.01-0.7 weight percent of an aliphatic or cycloaliphatic diamine (III) carrying a primary amino group and a tertiary amino group, and / or - 0.01-0.7 weight percent of 4-amino-2, 2, 6,6-tetra-alkyl piperidine (IV), in which the amounts of the components from I to IV are added to form 100 percent by weight, and the amount of the components III and / or IV form from 0.01-0.7 percent of weight. 2. Chain-regulated polyamide 6 according to the
2. Clause 1, characterized in that the amount of aromatic dicarboxylic acid (II) forms 0.2-0.6 weight percent.
3. 3. Chain-regulated polyamide 6 according to Clauses 1 and 2, characterized in that the quantity of components III and / or IV, respectively, forms 0.01-0.6 weight percent.
4. 4. Chain-regulated polyamide 6 according to Clauses 1 to 3, characterized in that the total amount of components III and / or IV form 0.05-0.6 weight percent.
5. 5. Chain-regulated polyamide 6 according to Clauses 1 and 2, characterized in that terephthalic and / or isophthalic acid is used as aromatic dicarboxylic acid (II).
6. 6. Chain-regulated polyamide 6 according to Clauses 1, 3 and 4, characterized in that 4-amino-2, 2, 6,6-tetramethyl-piperidine is used as component IV.