FIBRE-MATRIX SEMIFINISHED PRODUCT

Abstract

A flame-retardant single-, or multi-layered, fibre-matrix semi-finished product has a polyamide-based fibre-matrix that includes at least one organic phosphinic acid salt and/or a diphosphinic acid salt. A process for the production thereof includes impregnating a fibre ply, or plies, and consolidating the ply or plies into a composite.

Claims

1. A fibre-matrix semi-finished product comprising: one or more semi-finished fibre product plies made of endless fibres, wherein: the endless fibers are in the form of wovens, non-crimp fabrics, multiaxial non-crimp fabrics, stitched fabrics, braids, batts, felts, mats and unidirectional fibre strands or mixtures of these materials; and the semi-finished fibre product plies each have a basis weight of 5 g/m.sup.2 to 3000 g/m.sup.2; and a compound impregnating the entirety of all the semi-finished fibre product plies, the compound comprising: component A)—at least one polyamide having a relative solution viscosity of 2.0 to 4.0 in m-cresol according to DIN EN ISO 307 at 25° C., as the matrix polymer, and component B)—based on 100 parts by weight of component A), 5 to 100 parts by weight of at least one organic phosphinic acid salt of formula (I) and/or a diphosphinic acid salt of formula (II), and/or polymers thereof, ##STR00004## wherein R.sup.1 and R.sup.2 are identical or different and represent a linear or branched C.sub.1-C.sub.6-alkyl, and/or C.sub.6-C.sub.10-aryl, R.sup.3 represents linear or branched C.sub.1-C.sub.10-alkylene, C.sub.6-C.sub.10-arylene or C.sub.1-C.sub.6-alkylarylene or aryl-C.sub.1-C.sub.6-alkylene, M represents aluminium, zinc or titanium and/or a protonated nitrogen base, m is an integer from 1 to 4, n is an integer from 1 to 3, x is 1 or 2, and n, x and m in formula (II) simultaneously adopt only integers such that the diphosphinic acid salt of formula (II) as a whole is uncharged, and the fibre-matrix semi-finished product has a volume fraction of fibre materials of 25% to 65%, defined according to DIN 1310, and a volume fraction of air or gas of less than 15%.

2. The fibre-matrix semi-finished product according to claim 1, wherein the compound has an MVR according to ISO 1133 of 1 cm.sup.3/10 min to 100 cm.sup.3/10 min, and the MVR according to ISO 1133 is determined by means of a capillary rheometer.

3. The fibre-matrix semi-finished product according to claim 1, wherein the compound further comprises component C)—at least one salt of melamine and condensed phosphoric acids.

4. The fibre-matrix semi-finished product according to claim 3, wherein component C) is at least one of melamine polyphosphate, or melamine-intercalated aluminium, zinc or magnesium salts of condensed phosphates.

5. The fibre-matrix semi-finished product according to claim 4, wherein component C) is at least one of bismelamine zincodiphosphate, bismelamine alumotriphosphate, or melamine polyphosphate.

6. The fibre-matrix semi-finished product according to claim 1, wherein the compound further comprises component D)—zinc borate.

7. The fibre-matrix semi-finished product according to claim 1, wherein the compound further comprises component E)—talc.

8. The fibre-matrix semi-finished product according to claim 1, wherein the compound further comprises any one of: C) and D); C) and E); D) and E); or C), D) and E), wherein: component C)—at least one salt of melamine and condensed phosphoric acids; component D)—zinc borate; and component E)—talc, if component C) is present, a weight ratio of component B) to component C) is 95:5 to 60:40, based on 100 parts by weight of a sum of component B) and component C); if component D) is present, component D) is in an amount of 0.1 to 20 parts by weight, based on 100 parts by weight of component A); and if component E) is present, component E) is in amount of 0.01 to 50 parts by weight, based on 100 parts by weight of component A).

9. The fibre-matrix semi-finished product according to claim 1, wherein M is aluminium.

10. The fibre-matrix semi-finished product according to claim 1, wherein the protonated nitrogen bases are the protonated bases of 1,3,5-triazine compounds.

11. The fibre-matrix semi-finished product according to claim 1, wherein R.sup.1 and R.sup.2 are identical or different and represent linear or branched C.sub.1-C.sub.6-alkyl and/or phenyl.

12. The fibre-matrix semi-finished product according to claim 1, wherein the product is at least one of: over-moulded, under-moulded, surround-moulded, or has moulded-on functional elements.

13. The fibre-matrix semi-finished product according to claim 1, wherein the product is at least one of: over-moulded via an in-mould process IMF, under-moulded via an in-mould process IMF, surround-moulded, via an in-mould process IMF, or has functional elements moulded-on via an in-mould process IMF.

14. The fibre-matrix semi-finished product according to claim 1, wherein the product comprises 1 to 100 semi-finished fibre product plies, and the endless fibres are in the form of wovens or non-crimp fabrics.

15. The fibre-matrix semi-finished product according to claim 13, wherein the endless fibres are in the form of wovens.

16. A process for producing a single-layered fibre-matrix semi-finished product, the process comprising: applying a polymer compound to one or more semi-finished fibre product plies made of endless fibres, wherein: each of the semi-finished fibre product plies has a basis weight of 5 g/m.sup.2 to 3000 g/m.sup.2; and the semi-finished fibre product plies comprise the endless fibres in the form of wovens, non-crimp fabrics, multiaxial non-crimp fabrics, stitched fabrics, braids, batts, felts, mats and unidirectional fibre strands or mixtures of these materials; and the polymer compound comprises: component A)—at least one polyamide having a relative solution viscosity of 2.0 to 4.0 in m-cresol according to DIN EN ISO 307 at 25° C., and component B)—based on 100 parts by weight of component A), 5 to 100 parts by weight of at least one organic phosphinic acid salt of formula (I) and/or a diphosphinic acid salt of formula (II) and/or polymers thereof, ##STR00005## wherein  R.sup.1 and R.sup.2 are identical or different and represent a linear or branched C.sub.1-C.sub.6-alkyl, and/or C.sub.6-C.sub.10-aryl;  R.sup.3 represents linear or branched C.sub.1-C.sub.10-alkylene, C.sub.6-C.sub.10-arylene or C.sub.1-C.sub.6-alkylarylene or aryl-C.sub.1-C.sub.6-alkylene;  M represents aluminium, zinc or titanium and/or a protonated nitrogen base;  m is an integer from 1 to 4;  n is an integer from 1 to 3;  x is 1 or 2, and  n, x and m in formula (II) simultaneously adopt only integers such that the diphosphinic acid salt of formula (II) as a whole is uncharged; heating the semi-finished fibre product plies with the polymer compound to a temperature greater than or equal to the melting temperature of the at least one polyamide in the compound, and applying pressure to the plies to impregnate the polymer compound into the plies and consolidate the entirety of all of the semi-finished fibre product plies to provide a composite having a volume fraction of fibre materials of 25% to 65% defined according to DIN 1310, and a volume fraction of air or gas of less than 15%; and cooling and solidifying the polymer compound to obtain a fibre-matrix semi-finished product.

17. An article of manufacture comprising at least one fibre-matrix semi-finished product according to claim 1.

18. The article of manufacture according to claim 17, wherein the article is a component of: passenger vehicles, heavy goods vehicles, aircraft, aerospace vehicles, trains, garden appliances, domestic appliances, computer hardware, handheld electronic devices, leisure articles, sports equipment, machines, buildings, photovoltaic systems, or mechanical devices.

19. The fibre-matrix semi-finished product according to claim 1, wherein: the product comprises 2 to 40 semi-finished fibre product plies made of endless fibres; the semi-finished fibre product plies each have a basis weight of 100 g/m.sup.2 to 900 g/m.sup.2; component A) has a relative solution viscosity of 2.2 to 3.5 in m-cresol according to DIN EN ISO 307 at 25° C.; the compound comprises 10 to 65 parts by weight of component B); the volume fraction of fibre materials is 30% to 55%, defined according to DIN 1310; and the volume fraction of air or gas is less than 10%.

20. The fibre-matrix semi-finished product according to claim 1, wherein: the product comprises 2 to 10 semi-finished fibre product plies made of endless fibres; the semi-finished fibre product plies each have a basis weight of 150 g/m.sup.2 to 750 g/m.sup.2; component A) has a relative solution viscosity of 2.4 to 3.1 in m-cresol according to DIN EN ISO 307 at 25° C.; the compound comprises 20 to 60 parts by weight of component B); the volume fraction of fibre materials is 40% to 50%, defined according to DIN 1310; and the volume fraction of air or gas is less than 5%.

Description

EXAMPLES

Thermoplastic Matrix

[0182] The thermoplastic matrix was prepared by compounding. To this end, the individual components were mixed in a twin-screw extruder (ZSK 26 Compounder from Coperion Wemrer & Pfleiderer (Stuttgart, Germany)) at temperatures in the range from 25° C. to 310° C. and the resulting mixture was extruded, cooled until pelletizable, pelletized and subsequently milled.

[0183] The experiments employed as thermoplastic matrix i):

[0184] Component A): Polyamide 6 having a relative solution viscosity in m-cresol of 2.5 at 25° C., (Durethan® B26, from Lanxess Deutschland GmbH, Leverkusen, Germany)

[0185] Component B): Aluminium tris(diethylphosphinate), [CAS No. 225789-38-8] (Exolit® OP1240 from Clarant SE, Muttenz, Switzerland)

[0186] Component C): Melamine polyphosphate [CAS No. 218768-84-4] (Melapur® 200/70 from BASF, Ludwigshafen, Germany)

[0187] Component D): Zinc borate, [CAS No. 12767-90-7] (Firebrake® 500 from Deutsche Borax GmbH Sulzbach, Germany)

[0188] Component E): Talc (microcrystalline), [CAS No. 14807-96-6], Mistron® R10 from Imerys Talc Group, Toulouse, France (Rio Tinto Group).

[0189] Component F): Further additives selected from pigments (carbon black [CAS No. 1333-88-4]), mould release agents (ethylene bisstearylamide [CAS No. 110-30-5] as Loxiol® EBS from Emery Oleochemicals) and heat stabilizer (1,6-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylamino]hexane [CAS-No. 23128-74-7] as Irganox® 1098 from BASF, Ludwigshafen, Germany). The composition of component F) is the same in all examples.

Semifinished Fibre Product

[0190] The semifinished fibre product plies comprising endless fibres used in the examples and in the comparative example for the composites were a twill fabric made of filament glass having a 2/2 twill weave with 0.2 wt % silane size and a basis weight of 200 g/m.sup.2. The density of the glass employed therefor was 2.56 g/cm.sup.3.

Semifinished Composite Products

[0191] The semifinished composite products of the examples and the comparative example were produced on a static hot platen press. The fibre-matrix semifinished products having an edge length of 420 mm×420 mm consisted of 2 or 4 semifinished fibre product plies and in one case a polyamide compound matrix M1 and in another case a polyamide compound matrix M2, which were applied and distributed uniformly over the entirety of all semifinished fibre product plies and in each case resulted in an average fibre-volume content of 45% and in a thickness of 0.5 mm for 2 plies of semifinished fibre products or of 1 mm for 4 plies. To achieve consolidation and impregnation to afford the fibre-matrix semifinished product a surface pressure of 24 bar and a temperature of 300° C. were applied for 240 s in each case. Subsequent cooling to room temperature was effected over 300 s at constant pressure. The semifinished fibre product plies were thus homogeneously embedded in the sheet-form fibre-matrix semifinished product formed, no material/phase boundaries were formed in the matrix on account of the uniform single-layered matrix system; in terms of substance it was not possible to distinguish between inner embedding material and surface.

Semifinished Composite Product 2 (Test Speciment for Mechanical Testing According to ISO178)

[0192] For comparison, a fibre-matrix semifinished product having an edge length of 420 mm×420 mm was produced from 4 semifinished fibre product plies and a polyamide matrix M3 which was uniformly produced with an average fibre volume content of 45%/in a thickness of 1 mm. To achieve consolidation and impregnation, here too a surface pressure of 24 bar was applied for 240 s at a temperature of 300° C. Subsequent cooling to room temperature was effected over 300 s at constant pressure. The semifinished fibre product piles were thus homogeneously embedded in the sheet-form semifinished composite product 2 formed, no material/phase boundaries were formed in the matrix on account of the uniform single-layered matrix system; in terms of substance it was not possible to distinguish between inner embedding material and surface.

[0193] The fibre volume content was in all cases analysed according to DIN 1310. For statistical reasons 5 test specimens were analysed in each case.

[0194] The semifinished composite products of type 1 and 2 were subjected to further experimental analysis for pore content, i.e. inclusion of air or gas. To this end a General Electric Micro CT nanotom S instrument was used to analyse tomographs of a cross section of semifinished composite products 1 and of semifinished composite product 2. For statistical reasons three test specimens were analysed in each case, with 5 repeat measurements being performed on each of these. A pore content of 4-5% was determined for all semifinished composite products using optical evaluation software. For statistical reasons three test specimens were analysed in each case, with 5 repeat measurements being performed on each of these.

[0195] The type 1 and type 2 semifinished composite products were also subjected to experimental analysis for local fibre volume content. To this end a General Electric Micro CT nanotom S instrument was used to analyse tomographs of a cross section of semifinished composite product 1 and semifinished composite product 2. The glass fibre content inside the samples was evaluated to a depth of 50 μm. For statistical reasons three test specimens of every semifinished composite product were analysed in each case, with 5 repeat measurements being performed on each of these. For semifinished composite products of type 2 no glass fibres were detected down to a depth of 50 μm since said fibres are separate from the surface and covered by the unfilled surface layer. The fibre volume fraction in this region was thus 0%. In the semifinished composite products of type 1 no separating covering layers were detected but rather the glass fibre bundles were homogeneously enclosed and uninterrupted right up to the surface so that the claimed fibre volume fraction was found even in the region between the surface down to a depth of 50 μm.

[0196] The flame retardancy of the fibre-matrix semifinished products was determined according to method UL94V (Underwriters Laboratories Inc. Standard of Safety, “Test for Flammability of Plastic Materials for Parts in Devices and Appliances”, p. 14-18 Northbrook 1998). The specimens used therefor and having the dimensions 125 mm.Math.13 mm.Math.0.5 mm in thicknesses were cut out of the prefabricated fibre-matrix semifinished products (“semifinished composite product”) using a waterjet cutting apparatus.

[0197] Mechanical specifications were obtained from flexural strength from flexural tests according to ISO 178. To this end specimens having the dimensions 80 mm.Math.10 mm.Math.1 mm were cut out of the prefabricated fibre-matrix semifinished products (“semifinished composite product”) using a waterjet cutting apparatus.

[0198] The results were evaluated according to the magnitude of the flexural strength measured in MPa, in each case based on a fibre volume fraction of 45%, wherein “o” corresponds to the reference value without flame retardant additives used for evaluation. A “+” denotes a flexural strength which is identical or higher compared to the reference value, wherein “identical” is to be understood as meaning values which, taking into account measurement accuracy, are within ±3% of the reference value. A “−” denotes a flexural strength which is lower than the reference value by more than 3%.

TABLE-US-00001 TABLE 1 Thermoplastic matrix M1 M2 M3 Component A) [parts by wt] 100 100 100 Component B) [parts by wt] 50 50 Component C) [parts by wt] 11.5 11.5 Component D) [parts by wt] 2.3 2.3 Component E) [parts by wt] 5 Component F) [parts by wt] 1.5 1.5 1.5

TABLE-US-00002 TABLE 2 Semifinished composite product Ex. 1 Ex. 2 Comp. 1 Thermoplastic matrix M1 M2 M3 UL94 at 0.5 mm Class V-0 V-0 n.d. Flexural strength Assessment + + ∘

[0199] The test results show that use of the inventive thermoplastic matrix attains not only better flame retardancies but, surprisingly, also at least equal flexural strengths which indicates that as a result of the specific combination of the components the attachment of the matrix polymer to the fibre material is maintained and an inventive fibre-matrix semifinished product is accordingly not liable to delamination.