Polybutylene Terephthalate With Low THF Content

1 . An automotive interior part containing a composition based on polybutylene terephthalate and polyethylene terephthalate, wherein based on 100 parts by mass of polybutylene terephthalate the composition employs 5 to 30 parts by mass of polyethylene terephthalate with the proviso that polyethylene terephthalate and polybutylene terephthalate are present not as a copolymer but as a mixture.

2 . The automotive interior part as claimed in claim 1 , having a TVOC to be determined according to VDA 277 of <50 μgC/g and a VOC THF to be determined according to VDA 278 of <8 μg/g.

3 . The automotive interior part as claimed in claim 1 , wherein the polybutylene terephthalate has a viscosity number to be determined in a 0.5% by weight solution at 25° C. in a phenol/o-dichlorobenzene mixture in a weight ratio of 1:1 according to DIN EN ISO 1628-5 in a range from 50 to 220 cm 3 /g.

4 . The automotive interior part as claimed in claim 1 , wherein the polybutylene terephthalate has a Ti content to be determined by X-ray fluorescence analysis (XRF) according to DIN 51418 of ≤250 ppm.

5 . The automotive interior part as claimed in claim 1 , wherein the polyethylene terephthalate contains at least 80 mol %, based on the dicarboxylic acid, of terephthalic acid radicals and at least 80 mol %, based on the diol component, of ethylene glycol radicals.

6 . The automotive interior part as claimed in claim 1 , wherein the polyethylene terephthalate has an intrinsic viscosity in the range from about 30 cm 3 /g to 150 cm 3 /g measured analogously to ISO 1628-1 in phenol/o-dichlorobenzene—1:1 parts by weight—at 25° C. using an Ubbelohde viscometer.

7 . The automotive interior part as claimed in claim 1 , further comprising at least one filler in an amount in the range from 0.001 to 70 parts by mass based on 100 parts by mass of polybutylene terephthalate.

8 . The automotive interior part as claimed in claim 7 , wherein a filler from the group of talc, mica, silicate, quartz, titanium dioxide, wollastonite, kaolin, kyanite, amorphous silicas, magnesium carbonate, chalk, feldspar, barium sulfate, glass spheres and fibrous fillers is employed.

9 . The automotive interior part as claimed in claim 8 , wherein the fillers are treated with a silane-based adhesion promoter of general formula (I)

(X—(CH 2 ) q ) k —Si—(O—CrH 2r+1 ) 4−k   (I)

wherein

X is NH 2 —, carboxyl-, HO— or

q is an integer from 2 to 10,

r is an integer from 1 to 5 and

k is an integer from 1 to 3.

10 . The automotive interior part as claimed in claim 1 , wherein the part is selected from trim pieces, plugs, electrical components or electronic components.

11 . A method of preparing polybutylene terephthalate-based compounds for processing into injection molded parts having a TVOC to be determined according to VDA 277 of <50 μgC/g and a VOC THF to be determined according to VDA 278 of <8 μg/g, comprising compounding polybutylene terephthalate with at least polyethylene terephthalate, wherein per 100 parts by mass of polybutylene terephthalate 5 to 30 parts by mass of polyethylene terephthalate are employed, with the proviso that polyethylene terephthalate and polybutylene terephthalate are present not as a copolymer but rather as a mixture.

12 . A method for reducing the THF content in injection molded polybutylene terephthalate-based automotive interior parts, comprising compounding polybutylene terephthalate with at least polyethylene terephthalate, wherein per 100 parts by mass of polybutylene terephthalate 5 to 30 parts by mass of polyethylene terephthalate are present, with the proviso that polybutylene terephthalate and polyethylene terephthalate are present not as a copolymer but rather as a mixture.