Heat-conducting polycarbonates having improved flame protection by means of barium sulfate

Patent metadata

Field	Value
Publication number	US-11912865-B2
Application number	US-202017604078-A
Country	US
Kind code	B2
Filing date	Apr 9, 2020
Priority date	Apr 18, 2019
Publication date	Feb 27, 2024
Grant date	Feb 27, 2024

Abstract

The present invention relates to a thermoplastic composition comprising at least one aromatic polycarbonate, talc, at least one anhydride-modified alpha-olefin polymer, at least one organic flame retardant selected from: fluoropolymer-containing anti-drip agents, fluorinated sulfonic acid salts, organic phosphoric acid esters, phosphazenes or mixtures of at least two of the abovementioned agents and barium sulfate. The invention further relates to a production process for such a composition and to a molded article producible from this composition.The composition contains barium sulfate in an amount of ≥3% by weight based on the total weight of the composition. ≥5% by weight is preferred.

First claim

The invention claimed is:

1. A thermoplastic composition, comprising:
A) at least one aromatic polycarbonate;
B) talc;
C) at least one anhydride-modified alpha-olefin polymer having an acid number of ≥30 mg KOH/g and an average molecular weight M W of ≥4000 to ≤40 000 g/mol, wherein the average molecular weight M W is determined by gel permeation chromatography in ortho-dichlorobenzene at 150° C. with polystyrene calibration and the acid number is determined by potentiometric titration with alcoholic potassium hydroxide solution according to DIN ISO 17025:2005, wherein the anhydride-modified alpha-olefin polymer C) comprises ≥90.0% to ≤98.0% by weight of alpha-olefin polymer and ≥2.0% to ≤10.0% by weight of anhydride, wherein the reported % by weight values are based on the total weight of the anhydride-modified alpha-olefin polymer and sum to ≤100% by weight;
FR) at least one organic flame retardant selected from: fluoropolymer-containing anti-drip agents, fluorinated sulfonic acid salts, organic phosphoric acid esters, phosphazenes or mixtures of at least two of the abovementioned agents;
D) at least one inorganic compound distinct from talc;

wherein
the composition contains barium sulfate in an amount of ≥3% by weight based on the total weight of the composition;
the composition contains alkaline earth metal sulfates distinct from barium sulfate in an amount of ≥0% by weight to ≤25% by weight based on the total weight of the alkaline earth metal sulfates present in the composition;
the composition contains organic phosphoric acid esters in an amount of ≥0% by weight to ≤7.5% by weight based on the total weight of the composition and
the composition contains ≥0.5% by weight based on the total weight of the composition of fluoropolymer-containing anti-drip agents,
wherein in the case where the composition contains ≥0.1% by weight based on the total weight of the composition of fluorinated sulfonic acid salts, the content of fluoropolymer-containing anti-drip agents is ≥0.7% by weight based on the total weight of the composition.

2. The composition as claimed in claim 1 , wherein the composition contains ≥3% by weight based on the total weight of the composition of organic phosphoric acid esters.

3. The composition as claimed in claim 1 , wherein the composition contains ≥3% by weight based on the total weight of the composition of linear and/or cyclic phosphazenes.

4. The composition as claimed in claim 1 , wherein the composition contains
≥0% by weight to ≤1% by weight based on the total weight of the composition of oligomeric organic siloxanes and/or
≥0% by weight to ≤1% by weight based on the total weight of the composition of halogen-free organic sulfones and/or halogen-free organic sulfonates and/or
≥0% by weight to ≤1% by weight based on the total weight of the composition of boron nitride.

5. The composition as claimed in claim 1 , wherein the composition contains at least one polycarbonate or copolycarbonate comprising units based on bisphenol A.

6. The thermoplastic composition as claimed in claim 1 , wherein the talc has a D50 value for the particle size distribution determined by sedimentation analysis of ≥0.5 to ≤10 μm.

7. The thermoplastic composition as claimed in claim 1 , comprising:
A) ≥50% to ≤75% by weight of aromatic polycarbonate;
B) ≥15% to ≤35% by weight of talc;
C) ≥0.5% to ≤3% by weight of anhydride-modified alpha-olefin polymer having an acid number of ≥30 mg KOH/g and an average molecular weight M W of ≥4000 to ≤40 000 g/mol,
wherein the average molecular weight M W is determined by gel permeation chromatography in ortho-dichlorobenzene at 150° C. with polystyrene calibration and the acid number is determined by potentiometric titration with alcoholic potassium hydroxide solution according to DIN ISO 17025:2005;
FR) ≥0.7% to ≤0.9% by weight of fluoropolymer-containing anti-drip agent in combination with ≥0.1% to ≤0.3% by weight of fluorinated sulfonic acid salt; or
≥0.4% to ≤0.6% by weight of fluoropolymer-containing anti-drip agent in combination with ≥3% to ≤5% by weight of organic phosphoric acid ester; or
≥0.4% to ≤0.6% by weight of fluoropolymer-containing anti-drip agent in combination with ≥3% to ≤10% by weight of linear or cyclic phosphazene;
D) ≥3% by weight to ≤10% by weight of barium sulfate;
E) ≥0% by weight to ≤3% by weight of titanium dioxide;

wherein the reported % by weight values are based on the total weight of the composition and sum to ≤100% by weight.

8. The composition as claimed in claim 1 , comprising:
A) ≥52% to ≤55% by weight of aromatic polycarbonate having an average molecular weight M W of 23 000 g/mol to 25 000, a softening temperature VST/B 120 according to ISO 306:2014-3 of 145° C. to 150° C. and a melt-volume flow rate according to ISO 1133:2012-03 of 18.0 cm 3 /(10 min) to 20.0 cm 3 /(10 min) at 300° C. and a 1.2 kg load;
B) ≥28% to ≤30% by weight of talc having a D50 value for the particle size distribution of ≥2 μm to ≤2.5 μm;
C) ≥1% to ≤2% by weight of anhydride-modified alpha-olefin polymer having an acid number of ≥75 to ≤80 mg KOH/g and an average molecular weight MW of ≥20 000 to ≤21 000 g/mol,
wherein the average molecular weight M W is determined by gel permeation chromatography in ortho-dichlorobenzene at 150° C. with polystyrene calibration and the acid number is determined by potentiometric titration with alcoholic potassium hydroxide solution according to DIN ISO 17025:2005;
FR) ≥0.4% to ≤0.6% by weight of fluoropolymer-containing anti-drip agent and ≥5% to ≤8% by weight of cyclic phosphazene;
D) ≥7% by weight to ≤8% by weight of barium sulfate;
E) ≥0% by weight to ≤1.2% by weight of titanium dioxide;
wherein the reported % by weight values are based on the total weight of the composition and sum to ≤100% by weight.

9. The composition as claimed in claim 1 having at least two of the following properties:
a) the melt viscosity is ≥100 Pa s to ≤300 Pa s;
b) the Charpy impact strength is ≥20 kJ/m 2 ;
c) the Vicat B softening temperature is ≥115° C.;
d) the thermal conductivity is ≥0.68 W/m K;
e) the thermal conductivity is ≥0.2 W/m K;
f) the rating in the UL94V fire test is V-0;
g) the rating in the UL94-5V fire test is VA.

10. A process for producing a composition as claimed in claim 1 , comprising mixing the components A), B) C), FR) and D),
wherein
the talc B) employed is unsized talc,
before mixing the amounts of B) and C) are matched to one another such that per 10 parts by weight of unsized talc ≥0.10 to ≤1.4 parts by weight of component C are employed,
wherein the mixing of components A), B), FR) and D) comprises a mixing step of components A) and B) at a temperature above the melting temperature of the aromatic polycarbonate A) and
wherein component C) is added to the mixture simultaneously with or immediately after the melting of component A).

11. The process as claimed in claim 10 , wherein the mixing is carried out in a co-kneader.

12. A molding comprising a thermoplastically processed composition as claimed in claim 1 .

13. The molding as claimed in claim 12 , wherein the molding is a battery housing, a 2-component cooling body having an electrically conductive layer or an electronics housing.

Assignees

• Covestro Intellectual Property Gmbh & Co Kg

Inventors

• Schirwitz Christopher
• Hungerland Tim
• Grueter-Reetz Tanja
• Kruells Helmut

Classifications

• C08L69/00 Primary

  Compositions of polycarbonates; Compositions of derivatives of polycarbonates · CPC title

• C08G64/04

  Aromatic polycarbonates · CPC title

• C08J3/005

  Processes for mixing polymers · CPC title

• C08K2003/2241

  Titanium dioxide · CPC title

• C08K2003/3045

  Sulfates · CPC title