DE4413177A1 - Poly:amide(s) with inherent thermal stability - Google Patents

Abstract

The prodn. of polyamides (I) comprises polymerisation or polycondensation of the corresp. monomers in the presence of triacetone-diamine cpd(s). of formula (II). R = H or 1-20C hydrocarbyl, pref. 1-18C alkyl or benzyl. Also claimed are polyamides with inherent thermal stability, contg. a -NH-linked residue derived from (II) in the polymer chain. Also claimed is a process for the prodn. of filaments based on polycaprolactam modified with (II) as above, by melt spinning with take-off speeds of at least 4000 m/min. Also claimed are filaments obtd. by this process and fibres and sheet materials made from these filaments.

Description

The invention relates to improved polyamides. In particular, the Invention inherently heat stabilized polyamides. Furthermore concerns the Erfin a process for the preparation of these polyamides and their uses dung.

The heat resistance of polyamides, u. a. also of polyamide 6 and Polyamide 66 is not sufficient for some applications. So can z. B. Problems with staining due to chemical changes (oxidative / thermal damage) of the polymers with heat fixing (heat Setting-) processes of carpet threads or textile fabrics ben. These problems can be endless or cut threads (staple ser). It is known to stabilize the polyamides for ver to improve these properties. Such an addition can before, during or after the polymerization, e.g. B. also first during processing. The usual known stabilizers are mixed with the polymer and are not attached to the polymer chain the. You can therefore do more with processing or use or less easily migrate, evaporate or be washed out, so that the effectiveness of the stabilization in undesirably diminishes and contaminates the environment (Air, dye bath) can be delivered.  

DE-OS 20 40 975, Sankyo Co. Ltd., describes the stabilization syn synthetic polymers, u. a. also of polyamides, with 4-aminopiperidine derivatives. Among the multitude of 4-aminopiperidine derivatives listed there 4-amino-2,2,6,6-tetramethylpiperidine is also disclosed (cf. Page 8, No. 32 of the print). However, this piperidine derivative is not particularly emphasized nor is it used in an example turns. According to this document, the 4-aminopiperidine derivatives mixed with the finished polymers, without this sticking to the polymer chain are bound.

DE-PS 39 32 912, Sandoz, relates to polyamides which have residues in the molecule sterically hindered amino groups, in particular 2,2,6,6-tetramethylpiperi Contain dyl-4 residues. The number of residues is on average 5 to 200 per polyamide molecule. According to the patent, these polyami are suitable de u. a. to improve the dyeability of polyamides and as Light stabilizers for plastics; they should do this in quantities of 1-10 wt .-% are added and especially in the melt to be mixed in.

In an essay in poly. Deg. and staff. 21: 251-262 (1988) described that the light resistance of polyamide 66 by a Addition of 2,2,6,6-tetramethylpiperidin-4-ol (TMP) is improved. At post-condensation of the TMP-containing polyamide 66 in the melt at 275 ° C under a steam atmosphere, as the authors assume men, TMP reacts with the carboxyl end groups of the polyamide (see p. 259 of the essay). However, there are signs of an (unwanted) Networking during the later stages of exposure.

It is known to use amines or mono- or dicarboxylic acids as chain regulators to use in the polymerization of polyamides, in which  In practice, predominantly monocarboxylic acids are used for this purpose become.

An object of the present invention was to be inherently heat stabilized To provide te polyamides and processes for their preparation. It it was found that polyamides had already been used before or in Addition of triacetone diamine Compound of formula

can be stabilized against heat damage. Here R means Hydrogen (4-amino-2,2,6,6-tetramethylpiperidine) or hydrocarbon residues with 1 to 20 carbon atoms, preferably alkyl groups (4-amino-1-alkyl- 2,2,6,6-tetramethylpiperidine) with 1 to 18 carbon atoms, or a benzyl group. Thus, the present invention relates to a method of manufacturing position of polyamides, characterized in that the polymerization or polycondensation of starting monomers in the presence of mind at least one triacetone diamine compound of the formula

is carried out, wherein R is hydrogen or hydrocarbon radicals with 1 to 20 carbon atoms, preferably alkyl groups with 1 to 18 carbon atoms,  or a benzyl group. Preferred embodiments of the The inventive method are described in the subclaims. The invention further relates to an inherently heat-stabilized polyamide, by an amine residue chemically bonded to the polymer chain formula

is characterized, wherein R has the meaning given above. Preferred Polyamides according to the invention are in the corresponding subclaims Are defined.

The triacetone diamine compound is the starting monomers or polymerizing reaction mixture is added and is by reaction its primary amino group with the starting monomers or with the Carboxyl groups of the resulting polyamide at the chain end of the Polymer chain bound. The secondary amino group of the triacetondi amine compound does not react due to steric hindrance. Consequently the triacetone diamine compound also acts as a chain regulator.

Through the chemical bonding of the triacetone diamine compound to the Polymer chains of the polyamide become inherently stabilized polyamides receive. The method according to the invention thus offers the advantage that an otherwise for mixing a stabilizer into the polyamide required separate process step is no longer required. This eliminates problems or quality reductions such as those with Mix in a stabilizer after superficial application to the  Polyamide granules, due to incompatibility, reduced viscosity, emigration, Evaporate or wash out the stabilizer or a double load stress such as B. can arise during assembly. By the process according to the invention, the polyamides through the triac Tondiamine compound against damage caused by heat and Thermal oxidation protected during processing and use.

The polymerization or polycondensation of the starting monomers in The presence of the triacetone diamine compound is preferred according to the usual procedures. The polymerization of the Ca prolactams in the presence of triacetone diamine (R = H) for example according to the continuous described in DE 14 95 198 and DE 25 58 480 process. Polymerization of AH salt in the presence of triacetone diamine can according to the usual discontinuous Ver drive (see: Polymerization Processes pp. 424-467, especially pp. 444-446, Interscience, New York, 1977) or after a continuous Process, e.g. B. according to EP 129 196. Basically, they can Triacetone diamine compound and the starting monomers separately or be fed to the reactor as a mixture. It is preferable to run the Triacetone diamine compound according to a specified quantity / time program to.

In a preferred embodiment of the method according to the invention are used as starting monomers caprolactam or at least one Dicar Bonic acid A selected from adipic acid, sebacic acid and terephthalic acid re and at least one diamine selected from hexamethylene diamine and Tetramethylene diamine, or dicarboxylic acid diamine salts thereof, polymeric siert or polycondensed. Caprolactam is particularly preferred. When Dicarboxylic acid A are particularly preferred adipic acid and terephthalate acid. With appropriate selection of the starting monomers, the  Polymerization or polycondensation to the preferred polyamides Polyamide 6, polyamide 66, polyamide 46 or polyamide 610.

In a preferred embodiment, the triacetone diamine Ver binding of the starting monomers in an amount of 0.03 to 0.8 mol%, preferably from 0.06 to 0.4 mol%, in each case based on 1 mol Acid amide groups of the polyamide added. This quantity refers for example in the production of polyamide 6 to 1 mol of Ca. prolactam or in the production of polyamide 66 to 0.5 mol of AH salt. It was found that at levels less than 0.03 mole percent none Adequate stabilization is achieved, whereas quantities above 0.8 mol% of the desired degree of polymerization due to the regulator effect the triacetone diamine compound is not reached.

In a preferred embodiment of the invention, the triacetone diamine connection with at least one of the usual chain regulators com trimmed. Suitable chain regulators are e.g. B. monocarboxylic acids such as vinegar acid, propionic acid and benzoic acid. Here the chain regulator combination and the amounts used u. a. according to the desired one Amino end group content of the end product and according to the desired one Melt stability selected. The amino end group content is determined according to the desired dyeability of the threads or fibers. The Melt stability depends on the practical requirements the processing of the products, especially when spinning.

This preferably contains according to the inventive method placed polyamide 6 (polycaprolactam) next to the triacetone diamine Ver Binding dicarboxylic acids B as chain regulators. Especially with polyamide 6 possess such products in addition to the required melt stability, the desired dyeability of the threads or fibers and a good one  Heat stability also improves the strength of the resultant Threads, especially when spinning at very high speeds ten.

The chain regulator in combination with the triacetone diamine compound Dicarboxylic acids B used can be the same as those used as dicarboxylic acid A used dicarboxylic acids be his or different from it. You who which are preferably selected from: C₄-C₁₀-alkanedicarboxylic acids, in particular re adipic acid, azelaic acid, sebacic acid and dodecanedioic acid; C₅-C₈- Cycloalkanedicarboxylic acids, especially cyclohexane-1,4-dicarboxylic acid; as well as benzene and naphthalenedicarboxylic acids, especially isophthal acid, terephthalic acid and naphthalene-2,6-dicarboxylic acid. Preferably the dicarboxylic acids B are used in an amount of 0.06 to 0.6 mol%, preferably 0.1 to 0.5 mol%, based in each case on 1 mol of acid amide group pen of the polyamide.

The invention also relates to the use of the invention; inherent heat stabilized polyamides for the production of threads, fibers or Foils. The invention further relates to a method for producing Threads based on polycaprolactam by rapid spinning Take-off speeds of at least 4000 m / min as well as the resulting ones manufactured threads. In addition, the invention includes the uses dung threads produced according to the invention for the production of fibers and fabrics as well as those obtainable through this use Fibers and fabrics.

The invention is explained below with the aid of the examples.  

General information about the examples

The relative viscosity of the polyamides (granules and filaments) was in 1% solution (1 g / 100 ml) in concentrated sulfuric acid (96% by weight) determined at 25 ° C. The determination of the final group salary was performed as an acidimetric titration. The amino end groups were in a solution in phenol / methanol 70:30 (parts by weight) with Per titrated with chloric acid. The carboxyl end groups were in a solution in Titrated benzyl alcohol with potassium hydroxide solution.

The content of the polyamides in the triacetone diamine compound and possibly of dicarboxylic acids can be diluted after hydrolysis of a sample Mineral acid by analysis of the hydrolyzate by conventional methods, be determined by gas chromatography.

The heat resistance of the polyamide threads was determined under Conditions similar to those of heat setting processes in subsequent treatment levels such as B. Heat fixing (heatsetting) from BCF (bulked continuous filament) or fixation of textile fabric to a large extent correspond. Strands of each were drawn from the drawn threads 5 g deflected, together with the comparison samples on a holding device quickly placed in a convection oven preheated to 185 ° C and there as soon as they are measured again Leave the air temperature for a further 120 seconds. Then the Sample taken immediately and in air at 20 ° C room temperature cooled down. Threads to be compared were treated together.

As a measure of the damage occurred (compared to a untreated sample of the same thread) the decrease in the relative  Viscosity and the amino group content as well as the increase in the car boxyl group content.

The absolute decrease in the basic groups then becomes more practical assessment in a percentage decrease, based on converted the untreated yarn sample.

The maximum tensile strength expansion was carried out with a Uster-Tensorapid-I measuring device determined, the clamping length for pre-oriented threads (POY) 200 mm, was 500 mm for drawn and textured threads. The test The time until the threads broke was in the range of 20 ± 2 seconds. The The pretension force was 0.025 cN / dtex for POY and for stretched threads 0.05 cN / dtex.

The fineness-related maximum tensile force R _H was calculated according to the following equation:

R _H = F _H / Tt _v

where F _{H is} the maximum tensile force [cN] and Tt _{v is} the initial fineness [dtex]. The maximum tensile force was used for the maximum tensile force measurements.

The maximum tensile force elongation E _H was determined as the ratio of the change in length Δl when the maximum tensile force was reached to the initial length l _{v of} the test sample according to the following equation:

E _H = Δl100% / l _v

where Δl is calculated from the difference in the length of the sample at maximum tensile force, l _H , and the initial length l _v .

example 1

A VK tube according to EP 20946 was used as the polymerization reactor stainless steel, material no. 1.4541. The VK pipe had an operating volume of 340 l and was equipped with a heat transfer medium oil heated.

A mixture of 100 parts by weight of melted caprolactam, 0.5 Parts by weight of water and 0.33 parts by weight of terephthalic acid the VK tube up in the first reaction zone continuously in one Amount of 41 kg / h fed with stirring. At the same time, Triace tondiamine as a separate stream to the VK pipe in the first reaction zone fed continuously in an amount of 55 ml / h. The concentration of triacetone diamine was 0.087 mol%, the concentration Terephthalic acid 0.23 mol%, based in each case on 1 mol of caprolactam. The temperature of the first reaction zone was 266 ° C; the pressure in the vapor phase above the first reaction zone was 1.5 bar absolute. Polycaprolactam was discharged from the bottom of the VK tube, in granules transferred, extracted with hot water and dried. That dry The polymer had a relative viscosity of 2.70, an amino end group content of 39 meq / kg and a carboxyl end group content of 65 meq / kg.

The product was melted at 275 ° C on an Ems inventory Pilot spinning system with 23 g / min per nozzle from nozzles with a 0.2 mm hole  diameter and 0.6 mm nozzle channel length as godet POY quickly spun.

The speeds for the 1st duo were 4520 m / min, for the 2nd Duo 4530 m / min and the Barmag craft winder 4500 m / min.

The threads were placed in a Barmag blow chute below the nozzle Cross-blowing by an air stream with 20 ° C / 65% relative humidity and 0.4 m / sec cooled speed. The preparation was done with a commercially available preparation (Limanol E 100, Schill & Seilacher, 0.65% support on thread) via dosing pump and ceramic oiler in the Blow duct. The POY had the following characteristics: 72%, fineness-related maximum tensile force 4.1 cN / dtex, Uster normal test U% = 0.6.

Then it was cold on a Zinser 14 S draw twisting machine a stretching ratio of 1: 1.363 at 820 m / min. The so the threads obtained had a maximum tensile elongation of 37%, a fineness-related maximum tensile force of 5.2 cN / dtex and an Uster comparison Temperance U% (normal test) of 0.7. The titer was 43.1 f 12 dtex.

The relative viscosity was 2.70, the amino end group concentration was 35 and the carboxyl end group concentration was 63 meq / kg.

Comparative Example 1

Commercial polyamide 6 with a relative viscosity of 2.67 without triacetone diamine was verspon under identical conditions as in Example 1 nen. The POY had the following characteristics: maximum tensile elongation 73%,  Fineness-related maximum tensile force 4.0 cN / dtex, Uster normal test U% = 0.6.

It was then cold after with an aspect ratio of 1: 1.336 stretched. The threads thus obtained had a maximum tensile strength elongation of 43%, a fineness-related maximum tensile force of 4.8 cN / dtex and an U uniformity U% (normal test) of 0.5. The titer was 43.8 f 12 dtex. The relative viscosity was 2.66, the amino end content groups were 32 meq / kg and 53 meq / kg at carboxyl end groups.

The threads were heat treated for 120 seconds in air at 185 ° C subjected and showed the following values:

Table 1

Table 1 shows that the polyamides 6 according to the invention after the heat treatment, a smaller decrease in the relative Viscosity and amino group content as well as a minor increase of carboxyl group content show as the polyamide of comparison game 1 and thus have better heat stabilization.  

Example 2

Caprolactam was in the same VK tube as in Example 1 below Addition of 0.38 mol% terephthalic acid, 0.20 mol% triacetone diamine, 0.5% by weight water and 0.3% by weight titanium dioxide (as matting agent) polymerized. The polymerization was carried out at a throughput of 25 kg / h and a temperature of 255 ° C in the first reaction zone below Normal pressure carried out. The way of working corresponded to the of Example 1. The dried product had a relative viscosity of 2.37, an amino end group content of 45 meq / kg and one Carboxyl end group content of 79 meq / kg.

The product was melted in a Barmag single screw extruder zen and with a melt temperature of 270 ° C a spinning system of the type Barmag SP 42 fed. From a flow rate of 22.6 g / min and Nozzle and the use of 12-hole spinnerets with capillary drilling gene of 0.20 mm diameter and 0.60 mm length was found at 4500 m / min winding speed a spinning (POY) titer of 52 f 12 dtex. After passing a blow chute with cross flow blowing of 0.40 m / sec and preparation with 0.60 to 0.65% of a commercially available preparation ration (Limanol E 100 from Schill & Seilacher as an 8% solution) the threads were fed over 2 godet duos at 4510 and 4535 m / min deducted. An axis-driven Barmag craft winder was used as the winding head used. The POY had a maximum tensile elongation of 65%, one fineness-related maximum tensile strength of 4.6 cN / dtex and a cook shrinkage of 9%.

The POY was on a Rieter J5 / 10a 748 cold drawn in / min. The tension in the pre-stretching area was 0.8%, the total stretch ratio was 1: 1.298.  

The drawn filaments had a maximum tensile elongation of 36%, a fineness-related maximum tensile force of 5.2 cN / dtex, a titer of 44 f 12 dtex and an Uster value U% (normal test) of 0.7.

The relative viscosity was 2.41, which were amino end groups at 42 and the carboxyl end groups were determined at 74 meq / kg.

Comparative Example 2

Commercial polyamide 6 of the relative viscosity 2.39, which is not a tri Contained acetone diamine was in the manner described in Example 2 extruded. The threads were cooled and prepared as before described. It was spooled up at 4500 m / min. The POY had a maximum tensile strength elongation of 62%, a fineness-related one Maximum tensile strength of 4.2 cN / dtex and a cooking shrinkage of 9%.

The POY was cold stretched as in Example 2, the total stretch ratio in this case was 1: 1,279. The drawn filaments had a maximum tensile strength extension of 34%, a fineness-related one Maximum tensile force of 4.6 cN / dtex, a titer of 43.6 f 12 dtex and a Uster value U% (normal test) of 0.9.

The relative viscosity of the threads was 2.41, the amino end groups were determined at 25 and the carboxyl end groups at 65 meq / kg.

The threads would correspond to those of a textile stenter fixation subjected to the conditions (185 ° C hot air, 120 sec) and the following Measured key figures:  

Table 2

Table 2 clearly shows that in the presence of triacetone diamine Polyamide 6 polymerized caprolactam for better heat stabilization shows as the polyamide 6 of Comparative Example 2 that no triacetone di contains amine.

Example 3

Poly produced according to Example 2, but without the addition of titanium dioxide amide was spun according to example 2. The POY had a maximum tensile strength extension of 64%, a fineness-related maximum tensile force of 4.7 cN / dtex and a cooking shrinkage of 10%.

The drawing was carried out under the conditions listed in Example 2 The stretched threads then had a maximum tensile strength extension of 37%, a fineness-related maximum tensile force of 5.4 cN / dtex, one Cook shrinkage of 14%, Uster uniformity U% (normal test) of 0.8 and a titer of 44 f 12 dtex.  

The relative viscosity was 2.40, the amino end groups were 42 and the carboxyl end groups 74 meq / kg.

Comparative Example 3A / 3B

2 types of commercially available polyamide 6 with a relative viscosity of 2.40 (3A) and 2.44 (3B) were spun according to Example 2. The spinning temperature was 275 ° C, the speed of the godet duos 4510 or 4520 m / min.

Table 3

According to Table 3, the polyamide 6 according to the invention shows a better one Heat stabilization than the polyamides 6 of the comparative examples.

Example 4

Caprolactam was in the same VK tube as in Example 1 below Addition of 0.55% by weight (0.375 mol%) of terephthalic acid, 0.33% by weight (0.239 mol%) triacetone diamine, 0.5% by weight water and 0.3% by weight Polymerized titanium dioxide. The polymerization was at a throughput of 25 kg / h and a temperature of 255 ° C in the first reaction zone carried out under normal pressure. The working method corresponded to the rest of that of Example 1. The dried product had a relative Viscosity of 2.42, an amino end group content of 46 meq / kg and a carboxyl end group content of 70 meq / kg. The content of extra ingredients here were 0.38%.

According to Comparative Example 2, it was run without a godet at 4500 m / min spun, then cold with a draw ratio of 1: 1.229 stretched and sharpened at 600 m / min.  

The POY had a fineness of 52 f 12 dtex, 59% maximum tensile strength and a fineness-related maximum tensile force of 4.1 cN / dtex.

In the Elkometertest (slit width 45 µm) an average of 0.5 errors / 100 km measured.

After stretching, the maximum tensile strength was 36% and a fineness-related maximum tensile force of 4.3 cN / dtex. The titer was 46 f 12 dtex.

Comparative Example 4

Caprolactam was in the same VK tube as in Example 4 below Addition of 0.53% by weight (0.361 mol%) terephthalic acid, 0.5% by weight Polymerized water and 0.3 wt .-% titanium dioxide. The polymerization was at a temperature of 252 ° C in the first reaction zone carried out. The procedure was otherwise the same as in Example 4. The dried product had a relative viscosity of 2.39, one Amino end group content of 27 meq / kg and a carboxyl end group content of 92 meq / kg. The extractable content was 0.32%.

165 g of triacetone diamine were added to 50 kg of the above polyamide 6 chips (TAD) (0.33% by weight) liquid by mixing in a Rhön for 2 hours wheel mixer drummed up.

The schnitzel thus contained the same amount of TAD in substance admixed and practically the same terephthalic acid content (monopoly rized) as product 4 described above; except for the type of TAD addition matched the two products.  

The tumbled TAD does not (completely) feed into the chips. They remain TAD moist and have an intense amine smell. This own shaft is extremely disadvantageous to use, and are extensive Safety precautions required as TAD is corrosive.

In Example 4, the viscose builds during the dwell time in the spinning system normal on, while it drastically degrades in Comparative Example 4. The comparatively small change in example 4 is also advantageous of amino groups and extractable components (determination: 16 Hours extraction with methanol at reflux) and the fact that significantly less spinning smoke in the nozzle area during spinning arises.

Table 4

Chemical data of free-falling threads

The spinning and further processing took place under those in the example 4 listed conditions. The POY had a fineness of 52 f 12 dtex, 54% maximum tensile strength and a fineness-related maximum tensile  force of 3.8 cN / dtex. An average of 7.5 errors were found in the electrometer test (Nodules, capillary breaks, loops) / 100 km found.

After stretching, the maximum tensile strength was 35% and a fineness-related maximum tensile force of 4.2 cN / dtex.

Table 5

As can be seen in Table 5, the polyamide according to the invention 6 of Example 4 show lower error numbers in all processing stages as the polyamide 6 of comparative example 4, in which TAD the poly amide was mixed in substance.

In example 4, TAD is more completely / more firmly anchored in the polyamide than in Comparative Example 4. This is how extraction processes (such as Colorings) less amine in the aqueous phase.

After 1 hour extraction of POY wound without preparation with boiling water at reflux were the following chemical data certainly:  

Table 6

As can be seen from Table 6, the polyamide according to the invention remains the number of amino end groups before and after the extraction is the same, whereas in the comparative example after the extraction less amino End groups are available. Thus, in the polyamide according to the invention the extraction of less amine into the aqueous phase.

Claims (11)

1. A process for the preparation of polyamides, characterized in that the polymerization or polycondensation of starting monomers ren in the presence of at least one triacetone diamine compound of the formula is carried out, where R is hydrogen or hydrocarbon radicals having 1 to 20 carbon atoms, preferably alkyl groups having 1 to 18 carbon atoms, or a benzyl group. 2. The method according to claim 1, characterized in that the poly merisation or polycondensation to polyamide 6, polyamide 66, Polyamide 46 or polyamide 610 in the presence of the triacetone diamine Connection is carried out. 3. Inherently heat-stabilized polyamide, characterized by an amine radical of the formula chemically bonded to the polymer chain wherein R has the meaning given in claim 1. 4. polyamide according to claim 3, characterized in that it after one of the processes for the preparation of polyamides according to An saying 1 or 2 can be produced, in particular produced. 5. Polyamide according to claim 3 or 4, characterized in that it 0.03 to 0.8 mol%, preferably 0.06 to 0.4 mol%, of the amine radical based on 1 mole of acid amide groups in the polymer chain of the poly contains amids. 6. polyamide according to any one of claims 3 to 5, characterized in net that the polyamide in the form of threads, fibers or films is present. 7. Use of the polyamide according to one of claims 3 to 6 for Manufacture of threads, fibers or foils. 8. Process for the production of threads based on polycapro lactam according to one of claims 3 to 5 or produced according to one of claims 1 or 2 by rapid spinning on deduction speeds of at least 4000 m / min. 9. Threads produced according to claim 8.   10. Use of the threads produced according to claim 6 or 8 for Manufacture of fibers and fabrics. 11. Fibers and fabrics, obtainable through use according to Claim 10.