Polymerizable composition

Abstract

A polymerizable composition comprising a) at feast one cyclic amide, b) from 2.8 to 3.5% by weight, preferably from 2.9 to 3.1% by weight, of at least one blocked polyisocyanate, and c) from 1.2 to 1.4% by weight of at least one catalyst for the polymerization of the cyclic amide,
where the ratio by weight of components b) to c) is from 2.0 to 2.9 and the % by weight data are always based on the entirety of components a) to c).

Claims

1. A polymerizable composition comprising: a) from 95.5 to 95.9% by weight, based on the combined weight of components a), b) and c), of at least one cyclic amide, wherein the cyclic amide is laurolactam, caprolactam, or a mixture thereof, b) from 2.9 to 3.1% by weight, based on the combined weight of components a), b) and c), of at least one blocked aliphatic polyisocyanate, and c) from 1.2 to 1.4% by weight, based on the combined weight of components a), b) and c), of at least one catalyst for the polymerization of the cyclic amide, wherein components a), b) and c) combined make up from 50 to 100% by weight based on the total weight of the polymerizable composition.

2. The polymerizable composition as claimed in claim 1, wherein component b) comprises at least hexamethylene diisocyanate (HDI) as blocked aliphatic polyisocyanate.

3. The polymerizable composition as claimed in claim 1, wherein the at least one catalyst c) is selected from the group consisting of sodium caprolactamate, potassium caprolactamate, magnesium bromide caprolactamate, magnesium chloride caprolactamate, magnesium biscaprolactamate, sodium hydride, sodium, sodium hydroxide, sodium methanolate, sodium ethanolate, sodium propanolate, sodium butanolate, potassium hydride, potassium hydroxide, potassium methanolate, potassium ethanolate, potassium propanolate, and potassium butanolate.

4. A process for the production of the polymerizable composition as claimed in claim 1, the process comprising contacting the cyclic amide with the at least one blocked aliphatic polyisocyanate and the at least one catalyst.

5. The polymerizable composition according to claim 1, wherein the composition further comprises up to 50% by weight of fibrous material, based on the total weight of the composition.

6. The polymerizable composition according to claim 1, wherein: b) the blocked aliphatic polyisocyanate comprises at least hexamethylene diisocyanate (HDI); and c) the at least one catalyst is selected from the group consisting of sodium caprolactamate, potassium caprolactamate, magnesium bromide caprolactamate, magnesium chloride caprolactamate, magnesium biscaprolactamate, sodium hydride, sodium, sodium hydroxide, sodium methanolate, sodium ethanolate, sodium propanolate, sodium butanolate, potassium hydride, potassium hydroxide, potassium methanolate, potassium ethanolate, potassium propanolate, and potassium butanolate.

7. The polymerizable composition according to claim 6, wherein the at least one catalyst is selected from the group consisting of sodium hydride, sodium, and sodium caprolactamate.

8. A process for the production of a fiber composite material, the process comprising: ia) contacting the polymerizable composition as claimed in claim 1, with fibers to produce a fibered composition, or ib) contacting at least one of the individual components a), b) and c) of the polymerizable composition of claim 1 with fibers, followed by contacting the remaining components of the polymerizable composition of claim 1 with one another to produce a fibered composition; and ii) polymerizing the resultant fibered composition at a temperature of 120 to 300° C. to produce a fiber composite material, wherein the residual content of monomeric amide a) in the fiber composite material is at most 0.3% by weight, based on the fiber composite material.

9. The process as claimed in claim 8, wherein the polymerizable composition or the individual components a), b) and c) thereof is/are brought into contact with from 5 to 65% by volume of the fibers, based on the fiber composite material.

10. The process as claimed in claim 8, wherein the fibers comprise glass fibers.

11. A fiber composite material obtained by the process of claim 8.

12. The process as claimed in claim 8, wherein: the polymerizable composition or the individual components a), b) and c) thereof is/are brought into contact with 45 to 65% by volume of the fibers, based on the fiber composite material; the fibers comprise glass fibers; the fibers do not comprise reactive size; the fibered composition is polymerized at a temperature of 140 to 180° C.; and the residual content of monomeric amide a) in the fiber composite material is at most 0.25% by weight, based on the fiber composite material.

13. A fiber composite material obtained by the process of claim 12.

Description

EXAMPLES

(1) 200 g of ε-caprolactam and the quantity stated in table 1 of catalyst, sodium caprolactamate, CAS No. 2123-24-2 (18.5% by weight in caprolactam; in the form of Addonyl Kat NL (Rhein Chemie Rheinau GmbH)) were weighed into a three-necked flask.

(2) 200 g of ε-caprolactam and the quantities likewise specified in table 1 of Addonyl 8120 were charged to a second three-necked flask.

(3) Addonyl 8120 is a bilaterally caprolactam-blocked hexamethylene diisocyanate, specifically N,N′-hexane-1,6-diylbis(hexahydro-2-oxo-1H-azepine-1-carboxamide), CAS No.: 5888-87-9.

(4) The contents of the two flasks were melted in oil baths preheated to 135° C. The flasks were then evacuated for 10 minutes at that temperature. Nitrogen was then charged to the two flasks, and the oil baths were removed.

(5) The melts were cooled until the temperature of the melts was 100° C.

(6) Laid glass-fiber scrims were inserted into a pressure-tight mold (sheet mold) controlled in advance to a temperature of 150° C. and flushed with N.sub.2, and vacuum was then applied to the cavity.

(7) In the next step, the contents of the feed container were transferred into the cavity of the sheet mold by applying an increased pressure of N.sub.2, and polymerization was carried out to completion in said mold.

(8) Fiber content by volume was constant in all of the composite sheets produced, being about 50% by volume.

(9) The residual monomer contents of the fiber composite material were determined via extraction; the composite sheets were then directly sawn into test samples measuring 2×20×60 mm and sealed into airtight packs and dispatched to Polymer Service GmbH in Merseburg for determination of flexural strengths in accordance with DIN EN 2562.

(10) TABLE-US-00001 TABLE 1 Polymerization formulations used, residual monomer contents thus achieved, and flexural strengths measured in accordance with DIN EN 2562; removal of sheet from mold after 4 minutes (quantities in grams) Flexural Addonyl Kat NL Catalyst, strength 8120 % by pure RMC (longitudinal) Fiber* % by wt. wt. % by wt. in % in MPa CE1 A 1 4 0.74 0.62 933 CE2 A 1 6 1.10 0.47 1075 CE3 A 1.5 6 1.10 0.71 1017 CE4 A 1.69 3.21 0.59 0.78 900 CE5 A 2.0 3.0 0.56 0.99 1110 CE6 A 2.0 5.0 0.93 0.37 1123 CE7 A 2.0 6.0 1.10 0.59 1008 CE8 A 2.5 6.0 1.10 0.40 948 CE9 A 2.5 7.0 1.30 0.28 1050 CE10 A 3.0 6.0 1.10 0.53 950 Inv1 A 3.0 7.0 1.30 0.22 1337 CE11 A 4.0 7.0 1.30 0.40 1110 CE12 A 3.0 8.0 1.48 0.53 1010 CE13 A 4.0 8.0 1.48 0.71 1007 Abbreviations: CE: Comparative example Inv: Inventive RMC: Residual monomer content *Reinforcement A: Four plies of a laid glass-fiber roving scrim from Johns Manville (JM871). This involves a fiber with a commerciaily available non-reactive size appropriate for polyamide. in each case, 4 plies of the laid scrim were inserted into the cavity of the sheet mold.