TRANSPARENT COMPOSITIONS WITH GOOD ALCOHOL RESISTANCE AND FATIGUE STRENGTH
A transparent molding composition, including by weight: (a) from 30 to 90% of at least one (co)polyamide of formula PACMY/Z, (b) from 10 to 70% by weight of at least one semi-crystalline copolyamide of formula A/WS, (c) from 0 to 10% of at least one impact modifier chosen from the polyether block amides (PEBA) and the core-shell polymers, (d) from 0 to 2% by weight of at least one additive, (e) from 0 to 5% by weight of a prepolymer; the sum of the proportions of each constituent of said composition being equal to 100%, the composition having good alcohol resistance as determined by an ethanol resistance test.
1 . A transparent molding composition, comprising by weight:
(a) from 30 to 90% of at least one (co)polyamide of formula PACMY/Z, wherein:
PACM is bis(4-aminocyclohexyl)methane consisting of at least 30 mol % of trans,trans-bis(4-aminocyclohexyl)methane with respect to the sum of all the isomers of the PACM,
Y is at least one aliphatic dicarboxylic acid,
Z is a repeating unit chosen from a unit obtained from at least one amino acid or a unit obtained from at least one lactam, or a unit XY1 obtained from the polycondensation of at least one aliphatic diamine X and at least one aliphatic dicarboxylic acid Y1,
Z being comprised from 0 to 15% by weight in the PACMY/Z (co)polyamide, with respect to the sum of the constituents of the (co)polyamide,
(b) from 10 to 70% by weight of at least one semi-crystalline copolyamide of formula A/WS,
A being as defined for Z,
W being chosen from 3,3′-dimethyl-4,4′-diamino-dicyclohexylmethane (MACM) and PACM as defined hereinbefore,
S being an aromatic dicarboxylic acid,
said semi-crystalline copolyamide having a crystallization enthalpy measured during the cooling step at a rate of 20 K/min by DSC according to ISO standard 11357-3 of 2013 greater than 25 J/g,
(c) from 0 to 10%, preferentially from 3 to 6% of at least one impact modifier chosen from the polyether block amides (PEBA) and the core-shell polymers,
(d) from 0 to 2% by weight, preferably 0.1 to 1% by weight of at least one additive,
(e) from 0 to 5% by weight of a prepolymer;
the sum of the proportions of each constituent of said composition being equal to 100%,
said composition having good alcohol resistance as determined by an ethanol resistance test, determined by optical observation (transmittance and haze) on injected plates in a mirror-polished mold of 100×100×1 mm3 after stressing (plate attached to an elliptical mandrel imposing a deformation of up to 3%) in a predetermined environment (ESC), that is placed in ethanol for 24 hours, according to ISO 22088:2006, the measurement of transmittance and the measurement of haze on the injected plates, in a mirror-polished mold, of 1 mm thickness having a width and a length of 100 mm*100 mm being determined according to ASTM D 1003, before and after testing with alcohol, from said composition.
2 . The transparent composition according to claim 1 , wherein it has a transmittance at 560 nm on a plate of 1 mm thickness greater than 91% determined according to ISO standard 13468-2:2006 before said ethanol resistance test.
3 . The transparent composition according to claim 2 , wherein it has a transmittance at 560 nm on a plate of 1 mm thickness greater than 90% determined according to ISO standard 13468-2:2006 after said ethanol resistance test.
4 . The transparent composition according to claim 1 , wherein said composition has a haze determined according to ASTM D 1003, after testing with alcohol, of less than 5%.
5 . The transparent composition according to claim 1 , wherein said composition has good fatigue strength as determined by a strength test in which the minimum number of cycles at 18 MPa is 350,000 cycles,
said test being carried out on dry-conditioned bars according to the following operating conditions:
Bars: 80*10*4 mm3
Gap between jaws: 40 mm
Frequency: 5 Hz (no self-heating is observed at this frequency)
Test temperature: 23° C.
Servo-hydraulic dynamometer MTS810#1
Load cell: 25 KN
V-notch—thickness under notch 3.7 mm.
6 . The composition according to claim 1 , wherein the polyether block amide (PEBA) has a flexural modulus of less than 200 MPa, as measured according to ISO standard 178:2010 at 23° C.
7 . The composition according to claim 1 , wherein the PEBA has a density greater than or equal to 1, as determined according to ISO 1183-3:1999.
8 . The composition according to claim 1 , wherein Y is a C8 to C18 aliphatic dicarboxylic acid, preferably C9 to C16.
9 . The composition according to claim 8 , wherein Y is a C10 or C12 aliphatic dicarboxylic acid, preferably C12.
10 . The composition according to claim 1 , wherein the weight content of Z in the PACMY/Z copolyamide is 0.
11 . The composition according to claim 1 , wherein the weight content of Z in the PACMY/Z copolyamide is greater than 0 and Z is a repeating unit chosen from a unit obtained from at least one C6 to C18 amino acid, preferentially C8 to C12, more preferentially C10 to C12, or a unit obtained from at least one C6 to C18 lactam, preferentially C8 to C12, more preferentially C10 to C12, or a unit XY1 obtained from the polycondensation of at least one C4-C36 aliphatic diamine X, preferentially C6-C18, preferentially C6-C12, more preferentially C10-C12, with at least one C4-C36 aliphatic dicarboxylic acid Y1, preferentially C6-C18, preferentially C6-C12, more preferentially C8-C12, or a mixture thereof.
12 . The composition according to claim 1 , wherein Z is a repeating unit chosen from a unit obtained from at least one C6 to C18 amino acid, preferentially C8 to C12, more preferentially C10 to C12, or a unit obtained from at least one C6 to C18 lactam, preferentially C8 to C12, more preferentially C10 to C12.
13 . The composition according to claim 1 , wherein Z is a repeating unit chosen from a unit obtained from a C11 amino acid or a unit obtained from a C12 lactam, preferentially a unit obtained from a C11 amino acid.
14 . The composition according to claim 1 , wherein A is a repeating unit chosen from a unit obtained from at least one C6 to C18 amino acid, preferentially C8 to C12, more preferentially C10 to C12, or a unit obtained from at least one C6 to C18 lactam, preferentially C8 to C12, more preferentially C10 to C12.
15 . The composition according to claim 1 , wherein A is a repeating unit chosen from a unit obtained from a C11 amino acid or a unit obtained from a C12 lactam, preferentially a unit obtained from a C11 amino acid.
16 . The composition according to claim 1 , wherein said at least one additive is chosen from dyes, stabilizers, plasticizers, surfactants, nucleating agents, pigments, brighteners, antioxidants, lubricants, flame retardants, natural waxes and mixtures thereof.
17 . The composition according to claim 1 , wherein said composition has good overmolding capability with transparent polyamides, as determined by a wedge cleavage test, carried out according to ISO 10354:1992.
18 . An article manufactured from the composition as defined in claim 1 .
19 . The article according to claim 18 , wherein the article is manufactured by injection molding.
20 . An object obtained by injection molding with a composition as defined in claim 1 .