Dish support rack for dishwasher
The invention pertains to a dish support rack having outstanding resistance to chemically harsh environments, and possessing improved mechanical properties, said dish support rack comprising a metal wire frame coated with a polyamide composition [composition (C)] comprising: —more than 50% wt of a polyamide [polyamide (A), herein after], more than 50% moles of recurring units of said polyamide complying with formula: —HN—(CH 2 ) 6 —NH—C(O)—(CH 2 ) 8 —C(O)— [recurring units (R 6,10 )], and, optionally: —up to 10% wt of conventional filler(s) and/or additive(s), and to a method for its manufacture.
1. A dish support rack, comprising:
a metal wire frame coated with a polyamide composition, said composition comprising:
more than 50 weight % of a polyamide, that comprises recurring units, wherein more than 50 mole % of the recurring units are first recurring units according to the formula: —HN—(CH 2 ) 6 —NH—C(O)—(CH 2 ) 8 —C(O)—, and said polyamide exhibits a relative viscosity of at least 2.5 and of at most 4.2, when measured in formic acid, according to ISO 307 standard.
2. The dish support rack of claim 1 , wherein the polyamide is a co-polyamide, wherein the recurring units, further comprise second recurring units according to formula (I) or (II), provided that the second recurring units are different from the first recurring units:
—NH—R 1 —CO— (I),
—NH—R 2 —NH—CO—R 3 —CO— (II),
wherein:
R 1 , equal to or different from each other at each occurrence, is a divalent hydrocarbon group having from 3 to 17 carbon atoms;
R 2 , equal to or different from each other at each occurrence, is a divalent hydrocarbon group having from 2 to 18 carbon atoms; and
R 3 , equal to or different from each other at each occurrence, is a bond or a divalent hydrocarbon group having from 1 to 16 carbon atoms.
3. The dish support rack of claim 2 , wherein the polyamide is an aliphatic polyamide.
4. The dish support rack of claim 2 , wherein the second recurring units are selected from the group consisting of:
—NH(CH 2 ) 5 —CO—, (j)
—NH—(CH 2 ) 8 —CO—, (jj)
—NH—(CH 2 ) 9 —CO—, (jjj)
—NH—(CH 2 ) 10 —CO—, (jv)
—NH—(CH 2 ) 11 —CO—, (v)
—NH—(CH 2 ) 6 —NH—CO—(CH 2 ) 4 —CO—, (vj)
—NH—(CH 2 ) 6 —NH—CO—(CH 2 ) 10 —CO—, (vjj)
—NH—(CH 2 ) 6 —NH—CO—(CH 2 ) 12 —CO—, (vjjj)
—NH—(CH 2 ) 10 —NH—CO—(CH 2 ) 10 —CO— (jx)
—NH—(CH 2 ) 6 —NH—CO—(CH 2 ) 7 —CO—, (x)
—NH—(CH 2 ) 12 —NH—CO—(CH 2 ) 10 —CO—, (xj)
—NH—(CH 2 ) 10 —NH—CO—(CH 2 ) 8 —CO—, (xjj)
—NH—(CH 2 ) 4 —NH—CO—(CH 2 ) 4 —CO—, and (xjjj)
—NH—(CH 2 ) 4 —NH—CO—(CH 2 ) 8 —CO—. (xjv)
5. The dish support rack of claim 1 , wherein more than 60 mole % of recurring units of the polyamide are first recurring units.
6. The dish support rack of claim 5 , wherein all recurring units of the polyamide are first recurring units.
7. The dish support rack of claim 1 , wherein the composition comprises said polyamide in an amount of at least 60 weight % based on the total weight of the composition.
8. The dish support rack of claim 7 , wherein the composition comprises, based on the total weight of the composition, at least 90 weight % of the polyamide.
9. The dish support rack of claim 1 , wherein the composition further comprises a second polyamide that is different from said polyamide.
10. The dish support rack of claim 1 , wherein said composition further comprises at least one opacifying pigment.
11. The dish support rack of claim 10 , wherein the opacifying pigment is present in an amount of at least 0.1 weight % and at most 5 weight % each based on the total weight of the composition.
12. The dish support rack of claim 11 , wherein the composition comprises, based on the total weight of the composition, at least 0.3 weight % and at most 4 weight % of the at least one opacifying pigment.
13. The dish support rack of claim 11 , wherein the composition comprises, based on the total weight of the composition, at least 0.8 weight % and at most 2.5 weight % of the at least one opacifying pigment.
14. The dish support rack of claim 10 , wherein said composition further comprises coloured pigment(s) different from the opacifying pigment.
15. The dish support rack of claim 10 , wherein the at least one opacifying pigment-is selected from the group consisting of TiO 2 , ZnS 2 , ZnO, and BaSO 4 .
16. The dish support rack of claim 1 , wherein said composition comprises at least one stabilizer selected from the group consisting of hindered amine compounds, hindered phenol compounds, phosphorous compounds, and copper-containing stabilizers.
17. The dish support rack of claim 1 , wherein the composition consists essentially of:
the polyamide, wherein the polyamide is PA 6,10;
from 0.1 to 5 weight % of an opacifying pigment;
from 0.01 to 3.5 weight % of a hindered phenol compound;
from 0.1 to 5 weight % of a coloured pigment different from the opacifying pigment;
wherein each weight % is based on the total weight of the composition.
18. A method for manufacturing the dish support rack according to claim 1 , comprising applying a coating of the composition to a metal wire frame.
19. The method of claim 18 , wherein the step of coating comprises:
maintaining the composition, in the form of powder, in a coating chamber in fluidized state, and
introducing the metal wire frame, heated at a temperature exceeding melting point of the polyamide, in said coating chamber; and
removing, after a residence time in said coating chamber sufficient for achieving target coating thickness, the coated metal wire frame from the coating chamber.
20. The dish support rack of claim 1 , wherein the polyamide is a homo-polyaniide PA6.10.