Heat stabilized moulding composition
Non-fibrous-reinforced thermoplastic molding compositions comprising a metal powder as a heat stabilizer are provided. The metal powder has a weight average particle size (dm) of at most 1 mm and the metal in the metal powder is selected from the group consisting of elementary metals from Group VB, VIB, VIIB and VIIIB of the Periodic Table, and mixtures thereof. A thermoplastic polyamide is also provided with an Mw of at most 50,000 g/mol, or a blend of at least two thermoplastic polymers with Tmelt or Tg differing by at least 20° C., or a second thermostabilizer. The invention also relates to the use of these compositions in high temperature applications.
1. A non-fibrous-reinforced thermoplastic moulding composition consisting of:
a) a polymer composition comprising at least one thermoplastic polyamide having a weight average molecular mass Mw of at most 50,000 g/mol, and
b) 0.05 to 5 parts by weight (pbw) relative to 100 pbw of the polymer composition in the moulding composition of finely dispersed elementary iron powder as a thermo-stabilizing system having a weight average particle size (dm) of at most 100 μm,
c) a pigment;
d) one or more substances selected from inorganic salts, acidifying components and mixtures thereof, and, optionally,
e) at least 10 mass %, relative to the total mass of the composition, of non-fibrous inorganic fillers and/or
f) other auxiliary additives, not comprising fibrous reinforcing agents, wherein
the moulding composition exhibits reduced deterioration when exposed to an elevated temperature of 215° C. for a prolonged time period of 500 hours as compared to an identical moulding composition including a CuI/KI stabilization system but not including the elementary iron powder.
2. The moulding composition according to claim 1 , wherein the metal powder comprises elementary iron.
3. The moulding composition according to claim 1 , wherein the temperature T1 is at least 200° C.
4. The moulding composition according to claim 1 , wherein the thermo-stabilizing system comprises a second thermostabilizer selected from the group consisting of phenolic thermostabilizers, phosphates, aromatic amines and metal salts.
5. The moulding composition according to claim 1 , wherein the moulding composition consists of:
a. a polymer composition comprising
a.1. a first thermoplastic polymer being a semi-crystalline polyamide having a melting temperature (Tm-1) or an amorphous polyamide having a glass transition temperature (Tg-1), wherein each of the melting temperature Tm-1 and the glass transition temperature Tg-1 is denoted as a temperature T1 which is at least 200° C., and
a.2. a second thermoplastic polymer, being a semi-crystalline polymer having a melting temperature (Tm-2) or an amorphous polymer having a glass transition temperature (Tg-2), wherein each of the melting temperature Tm-2 and the glass transition temperature Tg-2 is denoted as a temperature T2 which is at least 20° C. lower than T1,
b. a thermo-stabilizing system, comprising:
b.1. the finely dispersed elementary iron having a weight average particle size (dm) of at most 1 mm, and
b.2. a copper salt, and, optionally,
c. non-fibrous inorganic fillers and/or other auxiliary additives not comprising fibrous reinforcing agents.
6. A process for forming a three-dimensional net-shaped moulded part comprising injection moulding of a moulding composition according to claim 1 .
7. A moulded part consisting of a non-fibrous-reinforced thermoplastic moulding composition according to claim 1 .
8. The moulding composition according to claim 1 , wherein the pigment is a black pigment.
9. A non-fibrous-reinforced thermoplastic moulding composition consisting of:
a) a polymer composition comprising
a1) at least one semi-crystalline thermoplastic polyamide having a melting temperature (Tm-1) or an amorphous polymer having a glass transition temperature (Tg-1), wherein each of the melting temperature Tm-1 and the glass transition temperature Tg-1 is denoted as a temperature T1, and
a2) a second thermoplastic semi-crystalline polymer having a melting temperature (m-2) or an amorphous polymer having a glass transition temperature (Tm-2) or an amorphous polymer having a glass transition temperature (Tg-2), wherein each of the melting temperature Tm-2 and the glass transition temperature Tg-2 is denoted as a temperature T2, and wherein T2 is at least 20° C. lower than T1,
b) 0.05 to 5 parts by weight (pbw) relative to 100 pbw of the polymer composition in the moulding composition of the finely dispersed elementary iron powder as a thermo-stabilizing system having a weight average particle size (dm) of at most 100 μm,
c) a pigment;
d) one or more substances selected from inorganic salts, acidifying components and mixtures thereof, and, optionally,
e) non-fibrous inorganic fillers and/or
f) other auxiliary additives, not comprising fibrous reinforcing agents, wherein
the moulding composition exhibits reduced deterioration when exposed to an elevated temperature of 215° C. for a prolonged time period of 500 hours as compared to an identical moulding composition including a CuI/KI stabilization system but not including the elementary iron powder.
10. The moulding composition according to claim 9 , wherein the pigment is a black pigment.
11. A non-fibrous-reinforced thermoplastic moulding composition consisting of:
a) a polymer composition comprising at least one thermoplastic polyamide, and
b) a thermo-stabilizing system comprising 0.05 to 5 parts by weight (pbw) relative to 100 pbw of the polymer composition in the moulding composition of finely dispersed elementary iron powder having a weight average particle size (dm) of at most 100 μm, and a second thermostabilizer,
c) a pigment;
d) one or more substances selected from inorganic salts, acidifying components and mixtures thereof, and, optionally,
e) non-fibrous inorganic fillers and/or
f) other auxiliary additives not comprising fibrous reinforcing agents, wherein
the moulding composition exhibits reduced deterioration when exposed to an elevated temperature of 215° C. for a prolonged time period of 500 hours as compared to an identical moulding composition including a CuI/KI stabilization system but not including the elementary iron powder.
12. The moulding composition according to claim 11 , wherein the pigment is a black pigment.