Method for producing polyamide composite materials containing silicon

Abstract

The invention relates to a method for producing polyamide composite materials containing silicon, comprising the copolymerisation of: a) at least one silicon compound (SV) having at least one silicon atom, said silicon atom having at least one lactamyl group of formula (A) bonded by means of the nitrogen atom thereof; b) the method also comprises copolymerisation with at least one comonomer (CM) that is selected from among ammonium salts of dicarboxylic acids, amino acids, amino acid amides and lactams. In formula (A), m represents a whole number between 1 and 11, in particular in between 2 and 9, and specifically 3, and # represents the connection to the silicon atom of the compound (SV).

Claims

1. A process for producing a silicon-containing polyamide composite material, comprising copolymerizing: a. at least one silicon compound SV comprising a silicon atom comprising a lactamoyl radical attached via its nitrogen atom and having a formula (A), ##STR00006## where m is an integer from 1 to 11 and # is the point of attachment to the silicon atom; with b. at least one comonomer CM selected from the group consisting of an ammonium salt of a dicarboxylic acid, an aminocarboxylic acid, an aminocarboxamide, and a lactam, wherein the at least one comonomer CM is such that water is formed during the copolymerizing, or water is added to the copolymerization reaction, wherein the silicon compound SV and the comonomer CM are present in such an amount of substance ratio that during the reaction at least 0.7 mol of water is formed per mole of lactam radicals of formula A attached to silicon atoms in the silicon compound SV, or a corresponding amount of water is added.

2. The process according to claim 1 wherein the silicon compound SV is selected from the group consisting of i), ii) and iii): i) a compound of formula (I) ##STR00007## where m is an integer from 1 to 11, x is 1, 2, 3 or 4, and R is optionally substituted C.sub.1-C.sub.6-alkyl, optionally substituted C.sub.2-C.sub.6-alkenyl, optionally substituted C.sub.1-C.sub.6-alkoxy, optionally substituted C.sub.3-C.sub.6-cycloalkyl, optionally substituted phenyl or optionally substituted phenyl-C.sub.1-C.sub.6-alkyl; ii) an oligomer comprising a repeat unit of formula (II); ##STR00008## where in is an integer from 1 to 11 and R is a lactamyl radical of formula (A) or has one of the meanings indicated for R in formula (I); and iii) a mixture of compounds of formula (I) and the oligomers comprising repeat units of formula (II).

3. The process according to claim 2, wherein the silicon compound SV is a compound of formula (I) where x is 3 or 4.

4. The process according to claim 1, wherein the copolymerizing is conducted at a temperature in a range from 150 to 280 C.

5. The process according to claim 1, wherein the comonomer is selected from the group consisting of: b1) an aminocarboxylic acid; b2) an ammonium salt of a dicarboxylic acid; b3) a mixture of at least one lactam with at least one ammonium salt of a dicarboxylic acid; and b4) a mixture of at least one lactam with at least one aminocarboxylic acid.

6. The process according to claim 1, wherein the comonomer is a mixture of at least one lactam and at least one aminocarboxylic acid or a mixture of at least one lactam and at least one ammonium salt of a dicarboxylic acid.

7. The process according to claim 6 wherein a molar ratio of the lactam to the aminocarboxylic acid or to the ammonium salt of a dicarboxylic acid is at least 1.1:1.

8. The process according to claim 5, wherein the aminocarboxylic acid or the ammonium salt of the dicarboxylic acid and the silicon compound SV are present in such an amount of substance ratio that a molar ratio of carboxyl groups in the comonomer to the lactam radicals of formula (A) attached to silicon atoms in the silicon compound SV is at least 0.9:1.

9. The process according to claim 1, wherein the comonomer comprises a lactam having a formula (III) ##STR00009## where in is an integer from 1 to 11.

10. The process according to claim 1, wherein the comonomer comprises an aminocarboxylic acid selected from the group consisting of compounds of formulae (IV) and (V)
H.sub.2N(CH.sub.2).sub.yCOOH(IV)
H.sub.2NCHR.sup.xCOOH(V) wherein: y in formula (IV) is from 1 to 20 and R.sup.x in formula (V) is optionally substituted C.sub.1-C.sub.6-alkyl, optionally substituted C.sub.2-C.sub.6-alkenyl, optionally substituted C.sub.1-C.sub.6-alkoxy, optionally substituted C.sub.3-C.sub.6-cycloalkyl, optionally substituted phenyl or optionally substituted phenyl-C.sub.1-C.sub.6-alkyl.

11. The process according to claim 1, wherein the comonomer comprises an ammonium salt of a dicarboxylic acid that is a salt of dicarboxylic of formula (IV) with a diamine of formula (VII)
HOOC(CH.sub.2).sub.zCOOH(VI)
H.sub.2N(CH.sub.2).sub.vNH.sub.2(VII) where z in formula (VI) is an integer from 1 to 12 and v in formula (VII) is an integer from 2 to 12.

12. A silicon-containing polyamide composite material obtained by the process according to claim 1.

13. The polyamide composite material according to claim 12 comprising from 0.1% to 10.0% by weight of silicon, based on a total weight of the composite material.

14. A film, fiber, monofilament, pipe, profile, semi-fabricated product, or plastic article, comprising the polyamide composite material according to claim 12.

15. The process according to claim 1, wherein the comonomer comprises an ammonium salt of a dicarboxylic acid.

16. The process according to claim 1, wherein the comonomer comprises an aminocaboxylic acid.

17. The process according to claim 1, wherein the comonomer comprises an aminocarboxamide.

18. The process according to claim 1, wherein the comonomer comprises a lactam.

Description

(1) The polyamide-silicon composites of the present invention and their production will now be more particularly elucidated by Examples 1 to 4, table 1 and FIGS. 1 to 7. These illustrate some aspects of the present invention and must in no way be construed as limiting the scope of protection.

(2) FIG. 1: .sup.29Si-{.sup.1H}-CP-MAS-NMR spectrum of composite material from Example 4

(3) FIG. 2: .sup.13C-{.sup.1H}-CP-MAS-NMR spectrum of composite material from Example 4

(4) FIG. 3: DSC curves of composite materials from Examples 1-4, 2.sup.nd heating curve of cyclic measurements, heating rate 10 K/min, 50 ml/min N.sub.2

(5) FIG. 4: ATR-FTIR spectra of composite materials from Examples 1-4

(6) FIG. 5: SEM/EDX images of platinum-coated composite material from Example 3

(7) FIG. 6: HAADF-STEM images of composite material from Example 3 at various resolutions

(8) FIG. 7: EDX images of platinum-coated composite material from Example 1

ABBREVIATIONS

(9) Smp.: melting point PMMA: methyl methacrylate HFIP: hexafluoroisopropanol DSC: differential scanning calorimetry GPC: gel permeation chromatography SEM: scanning electron microscopy EDX: energy-dispersive x-ray spectroscopy ATR-FTIR: attenuated total reflection Fourier transform infrared spectroscopy.
Analysis

(10) SEM/EDX images were recorded with a Nova NanoSEM 200 from FEI Company. The samples were coated with platinum before examination. The scale/magnification is indicated on the pictures.

(11) Solid state NMR investigations of pulverulent samples were carried out on a Bruker Avance 400 spectrometer (frequency of .sup.1H spectra: 400.13 MHz, .sup.13C spectra: 100.622 MHz) with a wide bore magnet and double resonance probe heads. .sup.13C{.sup.1H}-CP-MAS spectra were recorded with the aid of 4 mm rotor vessels. Referencing was against adamantane as external standard (=38.5 ppm). .sup.29Si{.sup.1H}-CP-MAS spectra were recorded with the aid of 7 mm rotor vessels. Referencing was against tetrakistrimethylsilylsilane as external standard (=9.5 ppm).

(12) DSC measurements were carried out with a DSC1 instrument from Mettler Toledo. Aluminum crucibles were used, crucible size 40 l. The measurement was made with a perforate lid under an applied nitrogen stream of 50 ml/min. Heating rate was 10 K/min

(13) Molecular weights were determined using gel permeation chromatography (GPC). The GPC measurements were carried out using an Agilent 1100 Series instrument from Agilent Technologies, USA, which had three columns (HFIP-LG Guard, and PL HFIPGel). The eluent used was hexafluoroisopropanol (HFIP)+0.05% CF.sub.3COOK. Polymethyl methacrylate (PMMA) was used as standard. The measurements were carried out under application of the following parameters: column temperature 40 C., flow rate 1 ml/min, concentration 1.5 mg/ml, filtered through Millipore Millex FG (0.2 m)

(14) The ATR-FTIR spectra were recorded using an FTIR spectrometer from BIO-RAD, FTS 165, with a Golden Gate accessory. The samples were applied directly to the measuring head and were held pressed in place by a sapphire anvil under a defined pressure of 5 bar. The measured data were captured by the Win-IR program 1M and depicted and evaluated using Origin.

(15) Quantitative analysis of the elements C, H and N in the pulverulent samples was formed using a varioMICRO CHNS instrument from Elementar Analysensysteme GmbH. Reported values are the means of duplicate determinations.

PREPARATION EXAMPLES

Example 1

Composite Material with 1.8% by Weight of SiO2

(16) A tank was initially charged with 15 g of -caprolactam, 3.3 g of -aminocaproic acid and 3.0 g of 1,1,1,1-silanetetrayltetrakis(azepan-2-one). The tank was subsequently purged with argon three times. The tank was pressurized to about 10 bar (argon) for the polymerization. The tank was heated to 230 C. in the course of about an hour, the stirrer being switched on at about 100 C. The temperature of 230 C. was maintained for 2.5 h. The pressure rose to about 15 bar in the course of the reaction. In the last 15 min, the pressure was gradually reduced to atmospheric.

(17) After cooling, the composite material was extracted with methanol for 16 hours.

(18) Smp. (DSC) 221 C.; elemental analysis mass % (by theory): C %: 61.0 (61.9), H %: 9.61 (9.64), N %: 11.8 (12.0), rest %: 17.6 (16.5)

Example 2

Composite Material with 5.0% by Weight of SiO2

(19) A tank was initially charged with 2.0 g of -caprolactam, 8.7 g of -aminocaproic acid and 9.3 g of 1,1,1,1-silanetetrayltetrakis(azepan-2-one). The tank was subsequently purged with argon three times. The tank was pressurized to about 10 bar (argon) for the polymerization. The tank was heated to 230 C. in the course of about an hour, the stirrer being switched on at about 100 C. The temperature of 230 C. was maintained for 2.5 h. The pressure rose to about 15 bar in the course of the reaction. In the last 15 min, the pressure was gradually reduced to atmospheric.

(20) After cooling, the composite material was extracted with methanol for 16 hours. Extractables amounted to 12%.

(21) Smp. (DSC) 220 C.; elemental analysis mass % (by theory): C %: 58.4 (58.3), H %: 9.24 (9.32), N %: 11.3 (11.3), rest %: 21.2 (21.1)

Example 3

Composite Material with 1.7% by Weight of SiO2/0.5% by Weight of Polysiloxane

(22) A tank was initially charged with 15.0 g of -caprolactam, 3.9 g of -aminocaproic acid, 0.6 g of 1,1,1-(methylsilanetriyl)tri(azepan-2-one) and 3.3 g of 1,1,1,1-silanetetrayltetrakis(azepan-2-one). The tank was subsequently purged with argon three times. The tank was pressurized to about 10 bar (argon) for the polymerization. The tank was heated to 230 C. in the course of about an hour, the stirrer being switched on at about 100 C. The temperature of 230 C. was maintained for 2.5 h. The pressure rose to about 15 bar in the course of the reaction. In the last 15 min, the pressure was gradually reduced to atmospheric.

(23) After cooling, the composite material was extracted with methanol for 16 hours. A composite material with 1.7% by weight of SiO.sub.2/0.5% by weight of polysiloxane was obtained.

(24) Smp. (DSC) 221 C.; elemental analysis mass % (by theory): C %: 62.1 (61.3), H %: 9.79 (9.29), N %: 12.0 (11.9), rest %: 16.2 (17.5)

(25) The GPC results are summarized in table 1.

Example 4

Composite Material with 4.0% by Weight of SiO2/1.1% by Weight of Polysiloxane

(26) A tank was initially charged with 6.0 g of -caprolactam, 11.9 g of -aminocaproic acid, 1.8 g of 1,1,1-(methylsilanetriyl)tri(azepan-2-one) and 9.0 g of 1,1,1,1-silanetetrayltetrakis(azepan-2-one). The tank was subsequently purged with argon three times. The tank was pressured to about 10 bar (argon) for the polymerization. The tank was heated to 230 C. in the course of about an hour, the stirrer being switched on at about 100 C. The temperature of 230 C. was maintained for 2.5 h. The pressure rose to about 15 bar in the course of the reaction. In the last 15 min, the pressure was gradually reduced to atmospheric.

(27) After cooling, the composite material was extracted with methanol for 16 hours.

(28) Smp. (DSC) 221 C.; elemental analysis mass % (by theory): C %: 61.0 (58.7), H %: 9.62 (9.38), N %: 11.8 (11.5), rest %: 17.6 (20.3)

(29) The GPC results are summarized in table 1.

(30) TABLE-US-00001 TABLE 1 GPC results for Examples 3 and 4; eluent HFIP + 0.05% CF.sub.3COOK, standard PMMA, column temperature 40 C. M.sub.n M.sub.w Dispersity Sample in g/mol in g/mol M.sub.w/M.sub.n Example 3 17000 45700 2.7 Example 4 15500 37500 2.4
Figure Description:

(31) FIG. 1 shows a .sup.29Si-{.sup.1H}-CP-MAS-NMR spectrum of the composite material from Example 4. It is apparent from FIG. 1 that a silicon dioxide network, evidenced by Q signals at about 100 ppm, with polysiloxane units, visible from T-signals at about 60 ppm, was formed.

(32) FIG. 2 shows a .sup.13C-{.sup.1H}-CP-MAS-NMR spectrum of the composite material from Example 4. Visible therein are not only all structural units of the resulting nylon-6 (methylene carbon at 25-50 ppm and carbonyl carbon at about 174 ppm) but also methyl groups of the polysiloxane network at about 7 ppm.

(33) FIG. 3 shows the 2.sup.nd heating curve of cyclic DSC measurements of the materials after extraction. The nylon-6 formed melts at about 220 C. Not only the -form but also the -form is apparent.

(34) The FTIR spectra in FIG. 4 show characteristic bands for the composite material formed. Apparent are not only typical bands for nylon-6 such as the NH stretching vibration at about 3300 cm.sup.1 or the amide I and II band, but also the SiO stretching vibration at about 1070 cm.sup.1, which is typical of the SiO.sub.2/polysiloxane network.

(35) FIG. 5 shows electron micrographs of the composite material from Example 3. In the chosen imaging variation, silicon looks light and all the other elements look darker. The micrographs show a relatively homogeneous distribution for the silicon across the sample cross section considered.

(36) FIG. 6 shows HAADF-STEM images of the composite material from Example 3. In this method of measurement, silicon-rich regions appear lighter than low-silicon regions. The images show the relatively homogeneous distribution for the silicon content. Primary particles about 5 nm in size are present in larger agglomerates.

(37) EDX images of the platinum-coated composite material from Example 1. The elemental distribution of silicon in the composite material from Example 1 is visible in FIG. 7. The silicon dioxide formed is present across the sample cross section in a relatively homogeneous distribution. The primary particles are partly agglomerated.