USE OF A POLYCARBONATE COMPOSITION

Abstract

The present invention relates to the use of a polycarbonate composition comprising an aromatic polycarbonate manufactured by an interfacial process and having a melt volume rate (MVR) of from 1-10 cm.sup.3/10 min (ISO 1133, 300 C., 1.2 kg), from 0.01 wt. % to 0.30 wt. % based on the weight of the polycarbonate composition, of an epoxy additive having at least two epoxy groups per molecule, and from 0.01 wt. % to 0.30 wt. % based on the weight of the polycarbonate composition, of a phenolic diphosphite derived from pentaerythritol, in an injection moulding process for the manufacture of an injection moulded article for reducing the formation of bubbles in said injection moulded article.

Claims

1-10. (canceled)

11. A method for the manufacture of an injection moulded article in an injection mould comprising at least one flow length of at least 50 cm, the flow length being defined as the shortest distance between a point of injection in the mould and an inner mould wall, the method comprising injection moulding a polycarbonate composition comprising: aromatic polycarbonate, from 0.01 wt. % to 0.30 wt. % based on the weight of the polycarbonate composition, of an epoxy additive having at least two epoxy groups per molecule, and from 0.01 wt. % to 0.30 wt. % based on the weight of the polycarbonate composition, of a phenolic diphosphite derived from pentaerythritol.

12. The method of claim 11, wherein the injection moulded article is an article of furniture.

13. An article, comprising: a polycarbonate composition comprising aromatic polycarbonate, from 0.01 wt. % to 0.30 wt. % based on the weight of the polycarbonate composition, of an epoxy additive having at least two epoxy groups per molecule, and from 0.01 wt. % to 0.30 wt. % based on the weight of the polycarbonate composition, of a phenolic diphosphite derived from pentaerythritol, wherein the article is prepared by injection moulding of said composition and wherein at least one flow length of the polycarbonate composition in an injection mould is at least 50 cm, the flow length being defined as the shortest distance between a point of injection in the mould and an inner mould wall.

14. The article of claim 13 wherein the aromatic polycarbonate is polycarbonate manufactured by an interfacial process and having a melt volume rate (MVR) of from 1-10 cm.sup.3/10 min (ISO 1133, 300 C., 1.2 kg), the epoxy additive is of the formula ##STR00009## and the phenolic diphosphite comprises 2,4-dicumylphenyl pentaerythritol diphosphite.

15. The article of claim 13, wherein said article is an injection moulded article of furniture.

16. The article of claim 15, wherein the furniture is a table, a chair, a stool or a couch.

17. The article of claim 16, wherein the furniture is a chair or a stool comprising a seat leg or stool leg of at least 20 cm.

18. The article of claim 13, wherein the article consists of the polycarbonate composition.

19. The method of claim 11, wherein the polycarbonate composition does not contain a silicone compound.

20. The method of claim 18, wherein the epoxy additive is a carboxylate epoxy resin

21. The method of claim 19, wherein the epoxy additive is an aliphatic epoxide having a molecular weight of at most 600 g/mol.

22. The method of claim 11, wherein the epoxy additive is of the formula: ##STR00010##

23. The method of claim 11, wherein the phenolic diphosphite is according to the formula: ##STR00011## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9, and R.sub.10 each independently represents hydrogen or a C.sub.1-20 organic radical.

24. The method of claim 23, wherein R.sub.2, R.sub.4, R.sub.5, R.sub.7, R.sub.9, and R.sub.10 are H, and R.sub.1, R.sub.3, R.sub.6 and R.sub.8 each independently represents a C.sub.1-20 organic radical.

25. The method of claim 11, wherein the epoxy additive is of the formula ##STR00012## and wherein the phenolic diphosphite comprises 2,4-dicumylphenyl pentaerythritol diphosphite.

26. The method of claim 11, wherein the aromatic polycarbonate has an MVR of 5-9 cm.sup.3/10 min as determined in accordance with ISO 1133 (300 C., 1.2 kg).

27. A method for the manufacture of an injection moulded article in an injection mould comprising at least one flow length of at least 50 cm, the flow length being defined as the shortest distance between a point of injection in the mould and an inner mould wall, the method comprising injection moulding a polycarbonate composition comprising: aromatic polycarbonate having an MVR of 0.1-10 cm.sup.3/10 min as determined in accordance with ISO 1133 (300 C., 1.2 kg), from 0.01 wt. % to 0.30 wt. % based on the weight of the polycarbonate composition, of an epoxy additive having at least two epoxy groups per molecule, and from 0.01 wt. % to 0.30 wt. % based on the weight of the polycarbonate composition, of a phenolic diphosphite derived from pentaerythritol; wherein the polycarbonate composition does not contain a silicone compound, and wherein the epoxy additive is an aliphatic epoxide having a molecular weight of at most 600 g/mol.

28. The method of claim 27, wherein the epoxy additive is of the formula ##STR00013## and wherein the phenolic diphosphite comprises 2,4-dicumylphenyl pentaerythritol diphosphite.

29. The method of claim 27, wherein the MVR is 2-9 cm.sup.3/10 min as determined in accordance with ISO 1133 (300 C., 1.2 kg).

Description

EXAMPLES

[0066] The following materials were used:

TABLE-US-00001 PC Polycarbonate homopolymer prepared with an interfacial process, having a molecular weight of about 30,000 g/mol (GPC using PC standards), a MFR of 6 g/10 min (ISO 1133, 300 C., 1.2 kg) CAEP Cycloaliphatic Epoxy Resin, 3,4-epoxycyclohexylmethyl-3, 4-epoxycyclohexyl carboxylate TDP Irgaphos 168, tris(2,4,-di-t-butylphenyl) phosphite S-9228 Doverphos S-9228, bis(2,4-dicumyl)pentaerythritol diphosphite Release Palmitic/Stearic Acid (50/50) ester of dipentaerythritol

[0067] The compositions of all the examples were moulded into test parts using a custom mould for the manufacture of test pieces for tensile bars. FIGS. 1 and 2 schematically show the test pieces comprising the tensile bars 2a and 2b and runners 3, 2a and 2b. In the injection moulding process the polycarbonate composition flows along the direction as indicated by means of the arrows. The top part of introduction runner 3 in FIG. 2 corresponds to the position where molten polycarbonate composition is injected into the mould. In other words, this point is the point of injection of the polycarbonate composition. The introduction runner 3 is connected to runners 2a and 2b as schematically shown in FIGS. 1 and 2. Runners 2a and 2b and tensile bars 4a and 4b are identical in dimensions. The combined length of runners 3 and 2a is equal to the combined length of runners 3 and 2b and is about 190 mm. The diameter of runner 3 is 5.9 mm at the injection point and 7.7 mm at the point where it splits into runners 2a and 2b. Runners 2a and 2b have a flatted cone cross sectional shape with a straight base having a width of 8.1 mm and a height 5.5 mm. The diameter at the cone is around 7.5 mm. The tensile bars 4a and 4b have a standard thickness of 4 mm and fulfill the requirements of the ISO 527-2 standard.

[0068] Injection moulding was carried out with a melt temperature of 300 C. and the mould temperature was set at 70 C. The injection pressure was kept relatively low, yet sufficient to completely fill the mould. No holding pressure was applied. These conditions were found to simulate the pressure conditions that would apply near the outer ends of a mould for complex parts, such as for example the legs of a stool. The test pieces were visually inspected on the presence of voids.

[0069] The table below shows the samples that were made.

TABLE-US-00002 CE1 CE2 E1 E2 E3 E4 E5 E6 E7 PC 99.55 99.50 99.49 99.48 99.47 99.46 99.45 99.42 99.40 CAEP 0 0.01 0.02 0.03 0.04 0.05 0.08 0.10 TPP 0.05 S-9228 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 Release 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 Voids + + +/

[0070] The amounts of the components are in weight percent on the basis of the composition. A + indicates the presence of voids in the material, whereas a indicates no voids were observed.

[0071] As is clear from the table the combination of S-9228 as the diphosphite and CAEP results in mouldings that do not contain voids or at least mouldings wherein the void formation is reduced to a minimum. With respect to Example 1 it was observed that some samples contain voids where others did not.