Thermoplastic compositions with enhanced mechanical properties

Abstract

The invention concerns novel reinforced thermoplastic compositions exhibiting an excellent compromise of properties, in particular mechanical properties. More particularly, the invention concerns compositions with slightly filled with small-diameter glass fibers. The compositions have in particular high impact resistance, good rigidity and satisfactory behavior when subjected to relatively high temperatures.

1 - 22 . (Canceled)  
     
     
         23 . A thermoplastic composition comprising: 
 a thermoplastic matrix, glass fibers having a diameter of less than 10 μm, with a proportion by weight of the glass fibers relative to the composition being less than or equal to 50%, and an impact modifier.    
     
     
         24 . The composition as claimed in  claim 23 , wherein the proportion by weight of the glass fibers relative to the composition is between 1 and 50%.  
     
     
         25 . The composition as claimed in one of the preceding claims, wherein the proportion by weight of the glass fibers relative to the composition is less than or equal to 30%.  
     
     
         26 . The composition as claimed in  claim 25 , wherein the proportion by weight of the glass fibers relative to the composition is less than or equal to 20%.  
     
     
         27 . The composition as claimed in  claim 23 , wherein the glass fibers present a diameter of less than or equal to 9 μm.  
     
     
         28 . The composition as claimed in  claim 23 , wherein the impact modifier is an elastomer.  
     
     
         29 . The composition as claimed in  claim 23 , wherein the impact modifier is present in a proportion by weight relative to the composition of less than 10%.  
     
     
         30 . The composition as claimed in  claim 29 , wherein the proportion of the impact modifier by weight relative to the composition is less than 8%.  
     
     
         31 . The composition as claimed in  claim 23 , wherein the thermoplastic matrix is polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamides 4-6, 6-10, 6-12, 6-36 and 12-12, a semiaromatic polyamide, a copolymer thereof, an alloy thereof, or an alloy of these polyamides with PET, PPO, PBT or ABS.  
     
     
         32 . The composition as claimed in  claim 23 , wherein the thermoplastic matrix is a thermoplastic polymer comprising H-shaped or star-shaped macromolecular chains having one or more cores and at least three branches or three polyamide segments connected to a core, linear macromolecular chains, said thermoplastic matrix having a melt flow index, measured in accordance with standard ISO 1133 at 275° C. under a load of 325 g, greater than 20 g/10 min.  
     
     
         33 . The composition as claimed in  claim 32 , wherein the H-shaped or star-shaped macromolecular chains and the sum of the H-shaped or star-shaped macromolecular chains and the linear chains in the thermoplastic matrix, present a ratio by weight of between 0.1 and 1.  
     
     
         34 . The composition as claimed in  claim 32 , wherein the thermoplastic matrix is a star polyamide obtained by copolymerization from a mixture of monomers comprising: 
 a) a polyfunctional compound having at least three identical reactive functions being an amine function or a carboxylic acid function,    b) monomers of general formulae (IIa) or (IIb) as follows:                          c) optionally, monomers of general formula (III) as follows:      Z-R 3 -Z   (III)    wherein:    Z represents a function identical to that of the reactive factions of the polyfunctional compound,    R 2  and R 3 , which are identical or different, represent substituted or unsubstituted aliphatic, cycloaliphatic or aromatic hydrocarbon radicals containing 2 to 20 carbon atoms and, optionally, heteroatoms,    Y is a primary amine function when X represents a carboxylic acid function, or    Y is a carboxylic acid function when X represents a primary amine function.    
     
     
         35 . The composition as claimed in  claim 32 , wherein the thermoplastic matrix is an H-shaped polyamide obtained by copolymerization from a mixture of monomers comprising: 
 a) a polyfunctional compound comprising at least three identical reactive functions being an amine function or a carboxylic acid function,    b) lactams or amino acids,    c) a difunctional compound being a dicarboxylic acid or a diamine,    d) a monofunctional compound whose function is either an amine function or a carboxylic acid function,    the functions of c) and d) being amine when the functions of a) are acid, the functions of c) and d) being acid when the functions of a) are amine, said functions having a ratio in equivalents between the functional groups of a) and the sum of the functional groups of c) and d) of between 1.5 and 0.66, and a ratio in equivalents between the functional groups of c) and the functional groups of d) of between 0.17 and 1.5.    
     
     
         36 . The composition as claimed in  claim 32 , wherein the thermoplastic matrix is obtained by extrusion of a mixture of polyamide obtained by polymerizing lactams or amino acids and a polyfunctional compound comprising at least three identical reactive functions being an amine function or a carboxylic acid function.  
     
     
         37 . The composition as claimed in  claim 34 , wherein the polyfunctional compound exhibits an arborescent or dendritic structure.  
     
     
         38 . The composition as claimed in  claim 34 , wherein the polyfunctional compound is represented by the formula (I)  
         R1-[-A-z ] m    (I)  
       wherein: 
 R 1  is a hydrocarbon radical having at least two carbon atoms, which is linear or cyclic, aromatic or aliphatic and optionally containing heteroatoms,  
 A is a covalent bond or an aliphatic hydrocarbon radical having 1 to 6 carbon atoms,  
 Z represents a primary amine radical or a carboxyl group, and  
 m is an integer between 3 and 8.  
 
     
     
         39 . The composition as claimed in  claim 38 , wherein the polyfunctional compound is 2,2,6,6-tetra(β-carboxyethyl)cyclohexanone, trimesic acid, 2,4,6-tri(aminocaproic acid)-1,3,5-triazine or 4-aminoethyl-1,8-octanediamine.  
     
     
         40 . The composition as claimed in  claim 23 , wherein the thermoplastic matrix is a copolyamide of random tree structure, obtained by polycondensation of: 
 at least one polyfunctional monomer satisfying the following general formula (V):      (AR 4 )—R—(R 5 ) n    (V)    wherein:    n is an integer greater than or equal to 2, between 2 and 10 (inclusive), R 4  and R 5 , identical or different, represent a covalent bond, an aliphatic, arylaliphatic, aromatic or alkylaromatic hydrocarbon radical,    R is a linear or branched aliphatic radical, a substituted or unsubstituted cycloaliphatic radical or a substituted or unsubstituted aromatic radical, optionally comprising two or more aromatic rings or heteroatoms,    A represents an amine function, an amine salt function, an acid function, ester function, acid halide function, or amide function,    B represents an amine or amine salt function when A represents an acid, ester, acid halide or amide function, and an acid, ester, acid halide or amide function when A represents an amine or amine salt function, at least one of the difunctional monomers of formulae VI to VIII below with optionally at least one of the monofunctional monomers of formula IX or X below, or with a prepolymer obtained from at least one difunctional monomer of formulae VI to VIII below and optionally at least one monofunctional monomer of formula IX or X below,    the difunctional monomers satisfying the following general formulae:      A 1 -R 7 -A 1    (VI)  B 1 —R 8 —B 1    (VII) or  A 1 -R 9 —B 1  or the corresponding lactams   (VII)    the monofunctional monomers satisfying the following general formulae:      R 10 —B 1    (IX), or  R 11 -A 1    (X)    wherein:    A 1  and B 1  represent respectively an acid, ester, acid halide or amide function and an amine function or an amine salt,    R 7 , R 8 , R 9 , R 10  and R 11  represent linear or branched alkyl hydrocarbon radicals, substituted or unsubstituted aromatic hydrocarbon radicals or alkylaryl, arylalkyl or cycloaliphatic hydrocarbon radicals, optionally including unsaturations.    
     
     
         41 . The composition as claimed in  claim 23 , wherein the thermoplastic matrix is a composition comprising a linear thermoplastic polymer and a thermoplastic star, H-shaped or tree polymer.  
     
     
         42 . The composition as claimed in  claim 23 , comprising a hyperbranched copolyamide.  
     
     
         43 . The composition as claimed in  claim 23 , further comprising an additive selected from the group consisting of stabilizing, pigmenting, flame retarding, catalyzing compound, reinforcing compound or a mineral filler.  
     
     
         44 . An article formed from a composition as claimed in  claim 23.