THERMALLY STABILIZED COMPOSITIONS

Abstract

The present invention relates to heat-stabilized polyamide 66-based compositions containing reinforcing materials based on at least one semiaromatic polyamide, at least one phenolic antioxidant and at least one polyhydric alcohol, to molding materials producible therefrom and in turn to injection-molded, blow-molded or extruded articles of manufacture producible therefrom.

Claims

1. A composition comprising: A) polyamide 66, B) at least one semiaromatic polyamide, C) at least one phenolic antioxidant, D) at least one polyhydric alcohol, and E) at least one reinforcing material, with the proviso that A) and B) do not form a copolymer.

2. The composition as claimed in claim 1, wherein based on 100 parts by mass of the component A) 6.0 to 50.0 parts by mass of the component B), 0.01 to 0.30 parts by mass of the component C), 1 to 5 parts by mass of the component D) and 17.5 to 185 parts by mass of the component E).

3. The composition as claimed in the claim 1, wherein component C) contains at least one unit of the formula (I) ##STR00002##

4. The composition as claimed in claim 1, wherein component C) comprises 1,6-bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamido)hexane.

5. The composition as claimed in claim 1, further comprising F) at least one demolding agent.

6. The composition as claimed in claim 1, further comprising G) at least one further additive distinct from components B) to F).

7. The composition as claimed in claim 1, wherein the semiaromatic polyamides employed are based on isophthalic acid or terephthalic acid and hexamethylenediamine.

8. The composition as claimed in claim 1, wherein component D) comprises a polyhydric alcohol having more than two hydroxyl groups.

9. The composition as claimed in claim 8, wherein the polyhydric alcohol is selected from the group of dipentaerythritol, tripentaerythritol, pentaerythritol and mixtures thereof.

10. The composition as claimed in claim 1, wherein component E) is selected from the group of carbon fibers, glass spheres, solid or hollow glass spheres, ground glass, amorphous silica, kyanite, calcium silicate, calcium metasilicate, magnesium carbonate, kaolin, calcined kaolin, chalk, powdered or ground quartz, mica, phlogopite, barium sulfate, feldspar, wollastonite, montmorillonite and glass fibers.

11. Combustion engine components comprising compositions according to claim 1.

12. Combustion engine components according to claim 11 selected from the group of turbocharged air ducts, intake pipes, valve covers, intercoolers and engine covers.

13. A molding material and article of manufacture producible therefrom containing a composition as claimed in claim 1.

14. A process for producing articles of manufacture, comprising: mixing the components of the compositions as claimed in claim 1 to form a mixture, extruding the mixture to form a molding material in the form of a strand, cooling and pelletizing the molding material to form a matrix material and subjecting the matrix material to injection molding, a blow molding operation or extrusion.

15. The use of a stabilizer system based on a semiaromatic polyamide, at least one polyhydric alcohol and at least one phenolic antioxidant for reducing photooxidative damage and/or thermooxidative damage to polyamide 66 admixed with at least one reinforcer or articles of manufacture producible therefrom in the form of films, fibers or moldings, wherein the polyamide 66 is not in the form of a copolymer with the semiaromatic polyamide.

16. The composition as claimed in claim 5, wherein component F) is present in an amount of from 0.05 to 0.50 parts by mass based on 100 parts by mass of the component A).

17. The composition as claimed in claim 6, wherein component G) is present in an amount of from 0.05 to 3.00 parts by mass based on 100 parts by mass of component A).

18. The composition as claimed in claim 8, wherein the polyhydric alcohol is dipentaerythritol.

Description

EXAMPLES

[0150] To demonstrate the advantages of compositions according to the invention and articles of manufacture producible therefrom, molding materials were initially produced in an extruder. Articles of manufacture in the form of flat bars obtained from the molding materials by injection molding were subsequently tested as unnotched test specimens in the freshly molded state and after prior aging in an impact test according to DIN EN ISO 180 1-U.

[0151] Production of the Polyamide Molding Materials

[0152] The individual components listed in table 1 were mixed in a ZSK 26 Compounder twin-screw extruder from Coperion Werner & Pfleiderer (Stuttgart, Germany) at a temperature of about 290 C., extruded in the form of a strand into a water bath, cooled until pelletizable and pelletized. The pelletized material was dried at 70 C. in the vacuum drying cabinet for about two days down to a residual moisture content of less than 0.12%.

[0153] Materials Used in the Context of the Present Invention: [0154] Component A): Polyamide 66, Vydyne 50 BWFS from Ascend Performance Materials LLC [0155] Component B): semiaromatic polyamide PA6I, Durethan T40 from Lanxess Deutschland GmbH [0156] Component C): Irganox 1098 from BASF [0157] Component D): dipentaerythritol [CAS No. 126-58-9] [0158] Component E): Glass fibers, chopped strands CS7928 from Lanxess Deutschland GmbH

[0159] Further Components Employed:

[0160] Polyamide 6, Durethan B29 from Lanxess Deutschland GmbH

[0161] Montan ester wax Licowax E from Clariant GmbH

[0162] Carbon black masterbatch: 50% in polyethylene

[0163] Nigrosin base NB masterbatch (Solvent Black 7) 40% in PA 6

TABLE-US-00001 TABLE 1 Compositions of molding materials (parts by mass based on 100 parts by mass of PA66) Ingredient Comp. 1 Ex. 1 PA66 100.00 100.00 PA6I 0.00 20.13 Copper(I) iodide 0.06 Phenolic antioxidant 1.11 Dipentaerythritol 3.39 4.42 Glass fibers 59.39 77.43

[0164] The glass fiber proportion in all molding materials was 35% of the total weight. The different values for the mass fractions of glass fibers come about since the compositions are based on 100 parts by mass of PA66 and this proportion changes as a result of the different amounts of additions.

[0165] Injection Molding:

[0166] The injection molding of the molding materials obtained was performed on an SG370-173732 injection molding machine from Arburg. The melt temperature was 290 C. and the mold temperature was 80 C. Flat bars according to DIN EN ISO 180 1-U and having nominal dimensions of 80 mm10 mm4 mm were molded as test specimens.

[0167] Aging and Testing:

[0168] In order to test aging behavior the test specimens were stored at 220 C. in a recirculating air drying cabinet for 1000 hours, 2000 hours and 3000 hours and subsequently tested in a Zwick impact testing machine under the conditions of ISO 180 1-U. The results obtained from the measurements were expressed relative to the initial value to determine therefrom the retention of impact strength after hot air aging.

TABLE-US-00002 TABLE 2 Results of hot air aging at 220 C. (Impact tests were carried out at room temperature (23 +/ 2 C.) Composition Comparison Example 1 Inventive example 1 Ageing at 220 C. Ageing at 220 C. 0 h 69 58 1000 h 38 48 rel. retention 55% 83% 2000 h 1 37 rel. retention 1% 63% 2500 h 32 rel. retention 55%

[0169] Surprisingly, the use of semiaromatic polyamides in PA66 compounds has the result that after hot air aging at 220 C. even after 2500 hours the impact strength is retained markedly above a value of 50% (rel. retention), thus demonstrating the markedly improved heat aging stability of compositions according to the invention/articles of manufacture producible therefrom.