CS246664B1 - Process for the preparation of polyalkylanoxide-modified polyamides - Google Patents

Abstract

The invention relates to a method for preparing polyamides modified with polyalkylene oxides, which consists in the polymerization and copolymerization of lactams of the general formula NH-ÍCHjlj,“^0· where x is 3 to 11 in the presence of 0.1 to 25 wt. percent, based on the total weight of lactams and polyalkylene oxide initiator at temperatures of 220 to 28(1 °C, which is initiated by equimolar compounds of anhydrous phosphoric acid with lactams of the general formula H3P04.NH-(0H2)χ-Τ:0, where x is 3 to 11 at a concentration of 0.1 to 20 mol «, based on the mixture of lactams and initiator.

Description

The invention relates to a method for preparing polyamides modified with polyalkylene oxides.

Modification of polyamides with polyalkylene oxides, especially polyethylene oxide, is used especially in the preparation of polyamide fibers to improve their antistatic properties. Polyalkylene oxides are dosed either to the initial polymerization mixture or to the polyamide melt before spinning. In the second method, only the physical binding of polyalkylene oxide to polyamide occurs and the result is (due to the solubility of polyalkylene oxides in water) a non-permanent antistatic effect.

The chemical bonding of polyalkylene oxide, i.e. the formation of a polyamide-polyalkylene oxide block copolymer, could most likely occur during the polymerization of lactams in its presence; however, the degree of incorporation of polyalkylene oxide depends on the polymerization mechanism used. However, with the most common hydrolytic mechanism, the content of incorporated, i.e. chemically bonded polyalkylene oxide in polyamide 6 reaches a maximum of 2 wt. %. This content can be somewhat increased with the acidolytic mechanism, but with a significant decrease in the degree of polymerization (Cupák F., Kubánek V., Kondelíková J., Týfová I.: Angew. Makromol. Chem. 121, 1 /1984/).

The formation of a block polymer is also supported by the use of polyalkylene oxide, the terminal hydroxyl groups of which have been replaced by more reactive, for example, amino, A, (i?-diaminopolyalkylene oxide) or carboxyl (<4,U3-dicarboxypolyalkylene oxide) terminal groups. In the case of et, W-diaminopolyethylene oxide, the anionic mechanism can also be used (Czech Republic AO 206 086 /1979/). However, the preparation of diamino or dicarboxy derivatives is technically and economically demanding and does not guarantee a 100% exchange of terminal groups. Residual hydroxyl groups then lead to undesirable side reactions, especially in the case of the anionic mechanism.

New initiators of cationic polymerization of lactams have been described recently - compounds of anhydrous phosphoric acid with lactams of (A)-amino acids of the general formula HjPO*.NH-(CH ₂ ) _χ -ϊθ, where x is 3 to 11. The polymerization of lactams of OJ-amino acids, initiated by these compounds, proceeds, depending on the type of lactams, the concentration of the initiator and the temperature, at a rate equal to or higher than hydrolytic polymerization. In addition, part of the phosphoric acid remains chemically bound in the polyamide chain and is the carrier of some improved properties of the polyamide, for example, reduced flammability or increased hydrophilicity (Gomola R., Alijev R., Kondelíková J., Králíček J.: Makromol. Chem., Rapid Commun. 4, 745 /1983/).

This invention builds on the above results. Its essence lies in the fact that the initiation of polymerization and copolymerization of lactams of the general formula NH-(CH ₂ ) _X ~CO, where x is 3 to 11 in the presence of polyalkylene oxides at a concentration of 0.1 to 25% by weight, based on the total weight of lactams and initiator, is carried out with an equimolar compound of anhydrous phosphoric acid with lactams of the general formula H^PO*.NH-(ČH ₂ > _x ~CO, where x is 3 to 11, at a temperature of 220 to 280 °C. Polyethylene oxide or its derivatives, terminated with amino groups or carboxyl groups, can be used as the polyalkylene oxide.

The effect of the method is that the resulting poly- and copolyamides contain chemically bound polyalkylene oxide, the content of which can be several times higher than in hydrolytic polymerization. At the same time, the process is significantly accelerated compared to hydrolytic polymerization at the same polymerization temperatures.

The content of incorporated polyalkylene oxide increases with increasing initiator concentration and, in the copolymerization of two or more lactams, is dependent on the ratio of monomer components; it increases especially with increasing concentration of 12-dodecanolactam in its copolymerization with 6-caprolactam.

The degree of polymerization of the resulting polymers increases with decreasing initiator content in the initial reaction mixture, so a wide range of copolymers can be prepared in this way, from lower molecular weight copolymers, which are powdery and can be applied, for example, as sorbents or for the preparation of dispersions, to high molecular weight copolymers, suitable for spinning, injection molding and extrusion.

The process according to the invention is further described in more detail with reference to several exemplary embodiments. All percentages relating to the composition of the polymerizing mixture are based on the mixture of lactams and initiator.

Example 1

6-caprolactam was polymerized in the presence of 0.7 mol % equimolar compound of anhydrous phosphoric acid with 6-caprolactam (P-Kl) and 2 wt % polyethylene oxide with a molecular weight of 1000 at 256 °C under a nitrogen atmosphere in a polymerization reactor used for hydrolytic polymerization. After 10 hours of polymerization, extraction with water and drying, 92 wt % of polymer with an intrinsic viscosity Et] = 1.65 (m-cresol, 25 °C) and an incorporated polyethylene oxide content of 1.6 wt % was obtained. The fiber prepared from this polymer was characterized by higher water absorption (0.4 %) and water sorption (by 6 %).

Example 2

6-caprolactam was polymerized in the presence of 5 mol% P-Kl and 10 wt% polyethylene oxide with a molecular weight of 1,000 (respectively 3,000) at 260 °C in a sealed evacuated glass ampoule.

After 2 hours of polymerization, extraction with water and drying, 72 wt. % of polymer was obtained.

0.57 and the content of ethylene oxide units in the polymer was 4 wt. % (or 66 wt. % of the polymer with Ct3 = 0.47 and the content of ethylene oxide units was 5.6 wt. %). At the same time, approximately 0.5 wt. % of phosphorus remained bound in the polymer.

Example 3

12-Dodecanalactam was polymerized in the presence of 2 mol % of an equimolar compound of anhydrous phosphoric acid with 12-dodecanalactam and 10 wt % of polyethylene oxide with a molecular weight of 1,000 at 280 °C for 12 hours by the method described in Example 2. 87 wt % of the polymer oW3· =1.44 was obtained, which contained 6.3 wt % of ethylene oxide units (extraction of the polymer was carried out with methanol).

example 4

6-caprolactam was polymerized in the presence of 0.4 mol % P-Kl and 5 wt % polyethylene oxide with a molecular weight of 1000 at 260 °C for 24 hours by the method described in Example 2. 85.5 wt % of polymer «M1 = 1.32» was obtained, in which 20% of the original amount of polyethylene oxide was chemically bound.

Example 5'

6-caprolactam was polymerized in the presence of 20 mol% P-Kl and 20 wt% polyethylene oxide of molecular weight 3000 at 260 °C for 2 hours by the method described in Example 2. 48.9 wt% of powdered polymer was obtained, in which 75% of the original amount of polyethylene oxide was chemically bound.

Example 6.

Copolymerization of a mixture of 6-caprolactam, 12-dodecanolactam, P-Kl and polyethylene oxide with a molar mass of 1,000 in the ratio shown in Table I at 260 °C by the method described in Example 2 (extraction of the polymerizate carried out with methanol) gave a polymer whose yield, composition and properties are described in Table I.

Table I

composition of the reaction mixture polymerization time h polymer content i m PEO content in polymer wt. % mol % wt. % K1 Dl P-Kl PEO 49 50 1 20 48 82.3 0.74 49 50 1 10 48 86.6 1.02 48 50 2 10 2 24.0 0.32 9.0 8 46.0 0.75 6.7 24 84.0 1.00 5.5 45 50 5 10 14 87.9 0.62 89 10 1 10 48 82.6 0.80 88 10 2 10 24 80.7 85 10 5 10 2.5 76.2 0.50 69 30 1 10 48 85.9 0.91 65 30 5 10 4 71.7 0.57

K1 stands for 6-caprolactam, Dl stands for 12-dodecanolactam and PEO stands for polyethylene oxide

Example 7

Copolymerization of a mixture of 35 mol % 6-caprolactam, 30 mol % 12-dodecanolactam, 30 mol % mixture of C-methyl-6-caprolactam isomers, 5 mol % P-K1 wt. % polyethylene oxide with a molecular weight of 1,000 at 260 °C for 18 hours was carried out by the method described in Example 2 (extraction of the polymer was carried out with methanol). 44.6% of powdered polymer with a melting point of 119 to 120 °C was obtained.

Example 8

Copolymerization of a mixture of 32 mol % 6-caprolactam, 32 mol % 8-octanolactam, 32 mol % 12-dodecanolactam, 4 mol % P-Kl and 25 wt % polyethylene oxide with a molecular weight of 1,000 at 280 °C for 18 hours was carried out by the method described in Example 2 (extraction of the polymerizate was carried out with methanol). 59.8 % of powdered polymer was obtained, in which 60 % of the original amount of polyethylene oxide was chemically bound.

Example 9 copolymerization of a mixture of 10 mol % 2-pyrrolidone, 85 mol % 6-caprolactam, 5 mol % equimolar compound of anhydrous phosphoric acid with 2-pyrrolidone and 15 wt % polyethylene oxide with a molecular weight of 3,000 at 220 °C for 20 hours was carried out by the method described in Example 2. 82% of the polymer was obtained, in which 55% of the original amount of polyethylene oxide was chemically bound.

Example 10

6-caprolactam was polymerized in the presence of 5 mol of P-Kl and 20 wt. % of et,Ci)-diaminopolyethylene oxide with a molar mass of 800 at 260 °C for 2 hours. 71 wt. % of polymer of 0.58 and a polyethylene oxide content of 12.7 wt. % was obtained. If, under otherwise identical conditions, 0.61 was used instead of et, (U-diaminopolyethylene oxide, 65 wt. % of polymer 0.61 was obtained, which contained 18.5 wt. % of polyethylene oxide.

Example 11

Copolymerization of a mixture of 45 mol % 6-caprolactam, 50 mol % 12-dodecanolactam, 5 mol % P-Kl, wt. % polyethylene oxide with a molar mass of 1,000 and 5 wt. % polypropylene oxide with a molar mass of 1,000 at 260 °C for 18 hours was carried out by the method described in Example 2 (extraction of the polymerizate was carried out with methanol). 78.9 wt. % of powdered polymer was obtained oEW = 0.54. If only polypropylene oxide was used instead of polyethylene oxide in an amount of 5 wt. percent and the polymerization was carried out for 6 hours, 79.2 wt. % of polymer was obtained oEW = 0.49.

Example 12

6-caprolactam was polymerized in the presence of 10 mol% P-Kl and 5 wt% polybutylene oxide at 230°C for 5 hours by the method described in Example 2. 71.2 wt% of powdered polymer was obtained.

Claims (3)

A process for the preparation of polyamides modified with polyalkylene oxides by polymerizing and copolymerizing lactams of the general formula NH- (Cl 2) _X ^- CO, wherein x is 3 to 11 in the presence of polyalkylene oxides in an amount of 0.1 to 25 wt. %, based on the total weight of the lactams and the initiator, characterized in that the initiation of the polymerization and copolymerization is carried out with an equimolar anhydrous phosphoric acid compound with lactams of the general formula Η ΡΟ Η ΝΗ Ο Ο Ο Ι-kde x Mp 220-280 ° C. 2. Process according to claim 1, characterized in that polyethylene oxide is used as the polyalkylene oxide. 3. A process according to claim 1, wherein the polyalkylene oxides used are derivatives thereof terminated with amino or carboxyl groups.