Semi-transparent polymer composite comprising a linear aliphatic polyamide
A polymer composite includes a linear aliphatic semi-crystalline polyamide having on average 10 to 14 carbon atoms in the monomer units, or the compound thereof, an S glass fiber, and a core-shell impact modifier. The polymer composite can achieve higher stiffness and impact strength without impairing the transparency significantly. The polymer composite can be used as molding material.
1. A polymer composite comprising:
(a) 87-91 wt % of polyamide PA12,
(b) 4-8 wt % of an S glass fiber comprising 64-66% SiO 2 , 24-25% Al 2 O 3 , 0-0.2% CaO, 9.5-10% MgO, 0-0.2% Na 2 O+K 2 O and 0-0.1% Fe 2 O 3 , based on the total weight of the glass, and
(c) about 5 wt % of a core-shell impact modifier comprising about 80 wt % of a core which comprises butadiene and no styrene units and about 20 wt % of a shell comprising methyl methacrylate,
wherein the wt % of (a), (b) and (c) are based on the total weight of the polymer composite and
a difference in refractive indices between the PA 12 according to (a) and the S glass fiber according to (b) at room temperature is less than 0.01,
and/or
a difference in refractive indices between the PA 12 according to (a) and the core-shell modifier according to (c) at room temperature is less than 0.01,
measured according to DIN EN ISO 489:1999 by method A.
2. The polymer composite according to claim 1 , wherein the S glass fiber does not comprise B 2 O 3 and/or TiO 2 .
3. The polymer composite according to claim 1 , wherein said polyamide is transparent with a haze not greater than 60%, measured according to ASTM D1003 on injection molded test specimens of 3 mm in thickness.
4. The polymer composite according to claim 1 , further comprising customary added substances with a total amount not greater than 10 wt % based on the total weight of the polymer composite.
5. The polymer composite according to claim 2 , wherein the S glass fibre does not comprise further oxides.
6. The polymer composite according to claim 1 , further comprising not greater than 10 wt % in total, based on the total weight of the polymer composite, of flame retardants, stabilizers, plasticizers, glass fibres, fillers, nanoparticles, antistats, dyes, pigments, mould-release agents, and/or flow assistants.
7. The polymer composite according to claim 1 , wherein said semi-crystalline polyamide has an enthalpy of fusion of 4 to 25 J/g as measured by the DSC method to ISO 11357 in the second heating step with a heating rate of 10 K/min and integration of the melt peak.
8. A molding material consisting of the polymer composite according to claim 1 .
9. A molding material, comprising:
the polymer composite according to claim 1 .
10. A molded article produced from the moulding material according to claim 9 .
11. The molded article according to claim 10 , suitable for electrical equipment, a sports item, optical equipment, a sanitary item, a hygiene item, household equipment, communications technology, automobile technology, energy technology, drive technology, mechanical engineering, and/or medical equipment.