Composite Materials Comprising a Reinforcing Material and a Thermoplastic Matrix, Precursor Compound Article of Said Materials and Products Obtained Using Same

Abstract

The invention relates to a precursor article of a composite material comprising a polymer matrix and at least one reinforcing wire and/or fibres, said article comprising at least one reinforcing wire and/or fibres and at least one polymer matrix wire and/or fibres. The invention also relates to composite materials comprising a reinforcing material and a thermoplastic matrix and to the articles obtained using said materials.

Description

Example 1

Semifinished slab produced from polyamide according to the invention and reinforcing yarns

A series of trials was performed using a polyamide Al multifilament yarn described above, having a strand linear density of between 21 and 22 dtex and a tenacity of about 23 cN/tex. Such a multifilament was assembled, in a multiaxial weaving operation, with a continuous glass reinforcing yarn having a linear density of 600 tex. To validate the high melt flow of the matrix, multiaxial woven fabrics were produced from elementary layers, each being defined as below:

Elementary Layer

• • ply 1: reinforcing yarn, −45° orientation
  • ply 2: reinforcing yarn, +45° orientation
  • ply 3: polyamide A1 (matrix) yarn, 90° orientation.

A laminated composite was then produced by placing several (between 2 and 10) elementary layers of the fabric obtained in a slab-shaped mold between the heated plates of a press, for a time of 1 to 3 minutes, under a pressure of between 1 and 20 bar and a temperature between 250 and 260° C. (above the melting point of the polyamide A1). After cooling down to a temperature of 50-60° C., the composite was demolded. The reinforcement content was then between 60 and 70% by weight.

The high melt flow of the polyamide A1 made it possible to achieve good impregnation of the reinforcement with the matrix without causing the reductions in mechanical properties or the fatigue strength problems observed with low-molecular-weight polymers. The mechanical properties in bending are compared with those of a thermoset-based composite obtained from the same reinforcing material and an epoxy resin in Table 1.

TABLE 1
Polyamide/glass fiber composite slab
	Tensile	Flexural	Elongation
	strength	modulus	at break
	(MPa)	(MPa)	(%)
	Epoxy matrix/glass	630.0	21 000	3.53
	fibers
	PA1 matrix/glass	517	21 000	3.26
	fibers

The use of a reinforcement in continuous yarn form makes it possible to maintain high mechanical properties in preferred directions. The fact of using the matrix in the form of a yarn provides, in addition to an economic advantage compared with the conventional solutions of powder coating or preimpregnation, easy handling and good control of the reinforcement content of the final composite.

Table 2 summarizes the mechanical properties obtained.

TABLE 2
Summary of the mechanical properties obtained
			PA A1/glass
			multiaxial
	Units	Standard	fabric
	Degree of	%		65
	impregnation (p/p)
	Density			1.8
	Simple tension
	Stress at break	MPa	ISO 527	545
	Young's modulus	GPa	ISO 527	21.3
	Elongation	%	ISO 527	2.76
	3-point bending
	Stress at break	MPa	ISO 14125	517
	Flexural modulus	GPa	ISO 14125	21
	Multiaxial shock
	Maximum force	DaN	ISO 6603-2	650

Claims

1-28. (canceled)

29. A precursor article of a composite material comprising a polymeric matrix and at least one reinforcing yarn and/or fibers, said article comprising at least one reinforcing yarn and/or fibers and at least one polymeric-matrix yarn and/or fibers, wherein: said reinforcing yarn and/or fibers are made of reinforcing material and optionally include a part made of a thermoplastic polymer;said polymeric-matrix yarn and/or fibers are made of a thermoplastic polymer, and in that:said thermoplastic polymer of said reinforcing yarn and/or fibers and/or of said polymeric-matrix yarn and/or fibers comprises at least one polycondensate consisting of:30 to 100 mol % (limits inclusive) of macromolecular chains satisfying the following formula (I): R3—(X—R2—Y)n—X—A—R1—A—X—(Y—R2—X)m—R3  (I)0 to 70 mol % (limits inclusive) of macromolecular chains satisfying the following formula (II): R4—[Y—R2—X]p—R3  (II)

30. The article as claimed in claim 29, wherein the thermoplastic polymer comprises at least one polyamide A1 having: 30 to 100 mol % (limits inclusive) of macromolecular chains satisfying the following formula (I): R3—(X—R2—Y)n—X—A—R1—A—X—(Y—R2—X)m—R3  (I)0 to 70 mol % (limits inclusive) of macromolecular chains satisfying the following formula (II): R4—[Y—R2—X]p—R3  (II)

31. The article as claimed in claim 29, wherein the thermoplastic polymer comprises at least one polyester A2 consisting of: 30 to 100 mol % (limits inclusive) of macromolecular chains satisfying the following formula (I): R3—(X—R2—Y)n—X—A—R1—A—X—(Y—R2—X)m—R3  (I)0 to 70 mol % (limits inclusive) of macromolecular chains satisfying the following formula (II): R4—[Y—R2—X]p—R3  (II)

32. The article as claimed in claim 29, wherein n, m and p are between 30 and 150.

33. The article as claimed in claim 30, wherein the polyamide A1 or the polyester A2 comprises at least 45 mol %, optionally at least 60 mol %, of macromolecular chains satisfying formula (I).

34. The article as claimed in claim 29, wherein R2 is a pentamethylene radical.

35. The article as claimed in claim 30, wherein the polyamide A1 or the polyester A2 is obtained by copolymerization from a monomer mixture comprising: a) a difunctional compound, the reactive functional groups of which are chosen from amines, carboxylic acids, alcohols and derivatives thereof, the reactive functional groups being identical;b) monomers of the following general formulae (IIIa) and (IIIb) in the case of the polyamide A1:

36. The article as claimed in claim 35, wherein compound a) represents between 0.1 and 2 mol % relative to the number of moles of monomers of type b) or b′).

37. The article as claimed in claim 30, wherein the polyamide A1 or the polyester A2 is obtained by melt blending a polyamide obtained by polymerization of lactams and/or amino acids or a polyester obtained by polymerization of lactones and/or hydroxyacids with a difunctional compound, the reactive functional groups of which are chosen from amines, alcohols, carboxylic acids and derivatives thereof, the reactive functional groups being identical.

38. The article as claimed in claim 37, wherein the difunctional compound represents between 0.05 and 2% by weight relative to the weight of polyamide or polyester.

39. The article as claimed in claim 32, wherein the difunctional compound is represented by formula (IV): X″—A—R1—A—X″  (IV)

40. The article as claimed in claim 32, wherein the difunctional compound is adipic acid, decanoic or sebacic acid, dodecanoic acid, terephthalic acid, isophthalic acid, hexamethylenediamine, methylpentamethylenediamine, 4,4′-diamino-dicyclohexylmethane, butanediamine, metaxylylenediamine, 1,3-propanediol, 1,2-ethanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or polytetrahydrofuran.

41. The article as claimed in claim 30, wherein the polyamide A1 or the polyester A2 is obtained by melt blending a polyamide of the type of those obtained by polymerization of lactams and/or amino acids or a polyester of the type of those obtained by polymerization of lactones and/or hydroxyacids, with a compound of formula (V): G—R—G  (V)

42. The article as claimed in claim 41, wherein the compound of formula (V) represents between 0.05 and 2% by weight relative to the weight of polyamide or polyester.

43. The article as claimed in claim 29, further comprising at least one matrix yam and/or fibers made of a linear thermoplastic polymer.

44. The article as claimed in claim 43, wherein the linear polymer is an aliphatic and/or semicrystalline polyamide or copolyamide which is nylon-4,6, nylon-6, nylon-6,6, nylon-6,9, nylon-6,10, nylon-6,12, nylon-6,36, nylon-11, nylon-12, a semicrystalline semiaromatic polyamide, a copolyamide, or a polyphthalamides.

45. The article as claimed in claim 29, wherein the matrix yarns and/or fibers further comprise additives, which are flame retardants, plasticizers, heat and light stabilizers, waxes, pigments, nucleating agents, antioxidants, or impact strength modifiers.

46. The article as claimed in claim 29, wherein the reinforcing yarns and/or fibers are carbon, glass, aramid, polyimide yarns or fibers.

47. The article as claimed in claim 29, wherein the reinforcing yarns and/or fibers are natural yarns, fibers, sisal, hemp or flax yarns.

48. The article as claimed in claim 29, further comprising a matrix precursor powder material.

49. The article as claimed in claim 48, wherein said matrix precursor powder material is a polyamide.

50. The article as claimed in claim 29, formed from continuous or chopped yarns, tapes, mats, braids, wovens, knits, webs, multiaxial fabrics, or nonwovens.

51. A composite, made by at least partial melting of the matrix yarns and/or fibers of an article as defined in claim 29.

52. The composite as claimed in claim 51, having a reinforcement content of between 25 and 80% by weight.

53. A process for the fabrication of a semifinished product, comprising the step of thermoforming or calendering the article as defined in claim 29, in order to at least partially melt the matrix yarns and/or fibers so as to impregnate the reinforcing yarns and/or fibers.

54. A process for the fabrication of a finished product, comprising the step of thermoforming the article as defined in claim 29, to a final shape, in order at least partially melt the matrix yarns and/or fibers so as to impregnate the reinforcing yarns and/or fibers.