FR2467907A1 - COMPOSITE MATERIALS CONSISTING OF FIBERS (GLASS, CARBON OR AROMATIC POLYAMIDE) IN THE FORM OF NON-WOVEN FABRICS, FABRICS OR KNITTED FABRICS, AND A NON-COMBUSTIBLE HYBRID MATRIX (SOLUBLE THERMOPLASTIC MACROPOLYMER AND NON-COMBUSTIBLE RESIN) AND PROCESS FOR MAKING THEM - Google Patents

Abstract

Composite materials consisting of fibers, for example carbon fibers, glass fibers, boron fibers or aromatic polyamides, in the form of nonwovens, fabrics or knits, and a non-flammable binder and stable at high temperatures. These materials comprise, as binder, a hybrid matrix made up of a soluble thermoplastic macropolymer and a thermosetting resin. These composite materials can be used as building elements, as thermal and electrical insulators, and also for fire protection.

Description

The present invention relates to composite materials which are

  consisting of fibers, for example glass fibers, carbon fibers or aromatic polyamide fibers (so-called 'Aramid' fibers) in the form of nonwovens, fabrics or knits, and a matrix resistant to high temperatures, i.e. non-combustible. It also concerns

  a process for making these composite materials

  your. The main fields of application of the composite materials according to the invention are those of the construction elements, thermal insulators and

  electrical and protective materials against

  catching fire. It is known that it is possible to manufacture very strong composite materials which withstand the thermal stresses with the help of resins or polymers having good resistance to high temperatures, by dissolving the impregnating resin in a solvent so as to obtain a varnish for impregnation, by impregnating with this varnish fibrous materials, such as carbon fibers, glass fibers, boron fibers or high modulus organic fibers of aromatic polyamides ("Aramids") in the form of nonwovens, fabrics or knits, then chasing

  the solvent by evaporation, which gives a material

  pre-impregnated fibrous material (so-called "prepreg") which can be processed by pressure molding, at high temperature, into fibrous laminates well resistant to

high temperatures.

  U.S. Patent No. 3,179,614 discloses fully aromatic linear polyimides with which

  soluble precursors, in this case polyamido acids

  carboxylic, manufacture laminates, this by performing the imidation at high temperature and under pressure. The passage of the polyamidocarboxylic acid to the totally aromatic polyimide, which takes place in a temperature range of 220 to 3000C, is accompanied by a release of water, which

  leads to the formation of pores in the laminate. always

  However, the presence of pores in the matrix is not

  good for the mechanical properties of

  fibrous positions and does not allow the properties to be

  fiber-specific techniques are fully exploited.

  This difficulty led to the development of resi-

  thermosetting polyimides ("duromers") which are described, for example, in French patents Nos. 1,455,514 and 1,555,564, in the published patent applications (first issues) of FRG Nos. 2,530,571, 2,754,632 and 2,754,631 and US Pat. Nos. 3,839,287, 3,689,464 and US Pat.

3,562,223.

  The resins of the patents and patent applications which have just been cited have in common that

  hardening, that is to say the transition from the mono-

  In the polymer state, this does not occur with the release of condensation products leading to pore formation when the resins are used to make fibrous laminates. However, they have the disadvantage

  to require, because of their solubility properties

  high polar solvents

  boiling point, for the preparation of the solution of

  gnation. These solvents, because of their good affinity for the resins, can not be eliminated completely.

  laminates with difficulty. The solvent that sub-

  the laminate after curing has a troublesome plasticizing effect, especially at high temperature, and ultimately

mechanical high temperature.

  We also know (state of the art)

  It is possible to use thermoplastic polymers

  such as polysulfones, as a matrix for fibrous laminates. To manufacture these fibrous laminates, pre-impregnated fibrous materials ("prepregs") with a very low thermoplastic polymer content, that is to say about 10 to 15, are placed in alternating layers in a hot-plate press. %, and sheets of the thermoplastic polymer and the whole is compressed at temperatures above the melting point of the thermoplastic prepreg of

  in order to obtain a homogeneous laminate devoid of

  res. But for this technique to be applicable, the thermoplastic resin must be soluble in solvents suitable for the casting of leaves,

  and that the linear polymer undergoes a true fusion.

  Naturally these laminates, because they contain a soluble binder, are sensitive to solvents; for them to be used at high temperatures, for example at 250 ° C, it is necessary that the melting points are of the order of 3500C or greater than

  this value (literature: Phillips & Murphy, RAE Tech-

  Report No. 76140 of October 1976).

  That being so, the present inventors have found that mixtures of soluble morphologically thermoplastic polymers and thermosetting resins ("duromers")

  can very well be made into loose sheets

  solvent, and that these sheets can be used to manufacture fibrous laminates, by the technique cited compression of polymer sheets and prepregs low in resins, in the press, to

high temperatures.

  The advantage of this procedure lies in the fact that, on the one hand, laminates which are completely solvent-free and pore-free are obtained and that, on the other hand, laminates obtained by virtue of the fact that they contain a thermosetting poly-imide. highly crosslinked, well resistant to solvents after curing. Another peculiarity, which is also a progress, is that one can easily adjust

  the rheological properties of compression in

  on the content of thermosetting fuse resin

  at low temperature. This means that the sheets

  melts them according to the content of the teermodurizing resin

  sand and according to its melting point. During the compres-

  it is therefore sufficient to apply working pressures

relatively weak.

  The subject of the present invention is

  composite materials consisting of fibers, for example glass fibers, carbon fibers, boron fibers or aromatic polyamide fibers, in the form of nonwovens, fabrics or knits, and a low-flammability binder and resistant to high temperatures, composite materials characterized in that

  comprise, as a binder, a hybrid matrix constituting

  killed from a soluble thermoplastic macropolymer and a

thermosetting resin.

  A good variant is characterized in

  what the ratio of the thermoplastic polymer to the

  thermosetting sine of the hybrid matrix is included

between 95: 5 and 5:95.

  As a thermoplastic component of the

  hybrid matrix, macropolytic

  soluble, high temperature resistant mother, taken as a whole consisting of polysulfones, poly-hydaritolnes, polycarbonates, polyamides,

  poly-imides, poly-amide-imides, poly-phenols

  nyl-quinoxaline, poly-benzimidazoles, polyoxa

diazoles and poly-benzoxazoles.

  Another good variant is characterized in that the thermoplastic component of the hybrid matrix is a soluble, temperature-resistant resin

  high, taken as a whole by the poly-

  esters, epoxides, bis-maleimides and prepoly-

  mothers with terminal acetylenic groups.

  Another variant, which is also highly appreciated, is characterized in that the hybrid matrix contains, as a thermoplastic component, a polyamideimide which can be obtained from the acid dianhydride

  benzophenone-tetracarboxylic acid, m-amino-ben-

  zoic acid and diamino-diphenylmethane and, as a

  thermosetting heat, a bis-maleimide corresponding to the general formula

O O

B N -A-N B

C C

  If! in which A represents a divalent organic radical with at least two carbon atoms and B represents one of the following divalent organic radicals: l] H 3 C C c

2C C

H H3C

X 3

-2467907

H2C% C H2CN

  Another variant, also very interesting

  Composite materials according to the invention are characterized in that the thermoplastic component is a polyether sulphone and the thermosetting component is a polyimide prepolymer which can be obtained by reaction of a bis-maleimide of the general formula o CBC or IC

N - A - N B

  C o with a diamine of general formula

H2N - D - NH2

  in which D represents a biva-

  at least two carbon atoms, the report

  molar port between the bis-imide and the diamine being from H 3 C 1 × C 11 C H and

  preferably between 1.2 and 5.

  The invention also relates to a method

  for making composite materials consisting of fibers, for example glass fibers, carbon fibers, boron fibers or aromatic polyamide fibers, in the form of nonwovens, fabrics or knits, and a hybrid matrix, non-flammable and resistant to high temperatures, consisting of a

  thermoplastic macropolymer and a thermosetting resin

  cissable, characterized in that compressed at high temperatures superimposed layers which are alternately sheets of the hybrid matrix

  and resin-poor prepregs of the hybrid matrix

  of. In order to manufacture the composite materials, the following procedure is preferably carried out: superposed alternating layers are placed in a press in which hybrid-solvent-free sheets of the matrix are obtained, in which sheets the thermosetting resin is in the uncured state, largely monomer, as well as "prepregs" which contain about 5 to% of the hybrid matrix, and pressurized

  at temperatures at which the thermosetting resin

  ble goes to the liquid state, after which the

  crosslinking under pressure at high temperature.

  The various steps in the manufacture of composite materials from a thermoplastic-thermosetting hybrid matrix are preferably as follows: a) manufacture of hybrid sheets consisting of a

  thermoplastic polymer resistant to high temperature

  and a thermosetting polyimide resin in the uncured state, b) producing a prepreg material, or prepreg, consisting of pre-oriented fibers in the form of rovings, fabrics, knits and nonwovens, and the hybrid matrix, the resin content being about 15%, c) compression of the sheets and prepregs to make it a laminate having good properties

  mechanical and high thermal stability.

  The different stages of operation and pro-

  which are preferably put into play for the new

  are described in detail in the following.

  So that we can apply the new

  method of manufacturing improved laminates

  At high temperature it is necessary to be able to manufacture hybrid sheets made of high temperature resistant thermoplastic polymer and thermosetting resin, itself stable at high temperature. The role of the thermoplastic polymer is

  to give the sheet the mechanical strength required

is.

  In principle, all the thermoplastic film-forming polymers which make it possible to manufacture, using solvents, prepregs with

low resin content.

  To make resistant laminates

  at high temperature, thermo polymers are used

  plastics that are themselves resistant to high

  temperature, for example polysulfones, poly-

  hydantoins, polycarbonates, aromatic polyamides

  ticks, polyamide-imides, polyimides, poly-

  phenyl-quinoxalines, poly-quinoxalines, poly-

  oxadiazoles and poly-thiadiazoles.

  By the US Patent; No. 3,708,458 discloses co-poly-imides which dissolve well

  in organic solvents, such as dimethylformate

  mide, dimethylacetamide and N-methylpyrrolidone, which can be used to make films by

  casting of their solutions in these solvents.

  To manufacture hybrid sheets, the thermosetting resin and the thermoplastic resin are dissolved in a solvent suitable for the two resins, and then a sheet is made on a support

by casting and drying.

  Another condition for the new process to be carried out is that it is possible to manufacture prepregs having a resin content of between 5 and 20% using a solution of the hybrid matrix, which is achieved to achieve,

  with soluble polymers, by passing the

  in the form of fabrics, knits, strati-

  son or nonwovens, through the solution, thereby impregnating the fibers, allowing the excess resin to flow and removing the solvents from the impregnated fibrous material, for example by drying,

  in a circulating air oven.

  The manufacture of the new composite materials is then carried out in a simple manner. The prepregs and the hybrid sheets are superposed in alternating layers and this stack is hardened in a heated platen press under pressure at a

  temperature for example between 170 and 2800C.

  This gives a laminate in the

  which hybrid matrix acts as a binder. The

  laminates are pore-free and have good

  mechanical properties. even at temperatures

of the order of 250C.

  The following examples illustrate the invention

without limiting its scope.

EXAMPLE 1

  For the manufacture of a laminate based on a glass fabric the following raw materials are used:

  a) a linear polyamide-imide (PAPI), morpholo-

  thermoplastic, which has been prepared for

  from the dianhydride of benzophenone

  tetracarboxylic acid, m-amino-benzoic acid

  and 4,4'-diaminodiphenylmethane. This poly-

  amide-imide is soluble in dimethylformate

  mide, dimethylacetamide and N-methyl-

  pyrrolidone and it has an inherent viscosity of

0.5 dl / g.

  b) 4,4-bis-maleimido-diphenylmethane as

sine imide thermosetting.

  c) a satin-woven glass cloth with a weight of 290 to 310 g / m2, which was primed with an aminosilane-based admixture

Trade.

  6.15 g of polyamide-imide are dissolved

  thermoplastic in 55.35 g of dimethylformamide.

  In addition, a solution of 6.15 g of

  maleimido-4,4'-diphenylmethane in 55.35 g of dimethyl

  formamide. We mix the two solutions and we

  thus obtaining a 10% solution of the hybrid matrix

  in dimethylformamide. A sheet is made with this solution by casting it onto a 400 x 400 mm crystal glass plate. The solvent is removed

  drying at 60 ° C. for 3 hours and at 75 ° C.

  in 18 hours, so much so that the sheet can be removed from the glass plate. After being dried in the circulating air oven for 19 hours at C the sheet has a residual solvent content

of 8.50%.

  In addition, a 15% solution of the hybrid matrix in dimethylformamide is prepared with a

  ratio of thermoplastic to thermosetting 1: 1.

  150 x 150 mm pieces of glass cloth are impregnated by soaking them in the solution of the hybrid matrix, the excess solution is allowed to flow, and the prepregs are dried in a circulating study.

  air at 70C for 18 hours. With only one

  ge we obtain prepregs whose content in the hybrid matrix is 9 to 10%; after two soaks, the resin content is 16 to 17%. The prepreg has a content

residual solvent 0.75%.

  To make a laminate based on a glass fabric is superposed in alternate layers, between two sheets of aluminum, 8 prepregs based on glass fabric and 9 hybrid sheets, the whole is hardened in a press platens heated during

  3 hours at 2200C under a pressure of 3.9 MPa,

  then we cool, unmolded and annealed at 250C

for 15 hours.

  The laminate obtained has the following properties at room temperature: Fiber content 45% by volume Resin content 55% by volume Density 1.82 g / cm Resistance to 4.7 MPa (DIN 53452) flexion 189 MPa ( DIN 53452) Flexural modulus Interlaminar shear strength

0.44 MPa.

  At 250 C the residual mechanical strength

  is still 70% of the starting value.

EXAMPLE 2

  The procedure described in Example 1 is applied to manufacture a laminate based on a

  glass fabric, compact, devoid of pores and resistant

  both at high temperature. Instead of the polyamide-imide, a copolyether sulfone is used as the thermoplastic component of the hybrid matrix. Due to the good film-forming properties of polysulfone, due

  high molecular weight, the ratio of thermoplastic

  that the thermosetting is 1: 2.

  As resin, as in Example 1 diphenylmethane. The laminate at 3.9 MPa has the properties Fiber content Density Flexural strength Flexural modulus Interlaminar shear strength

A 2000 C

still present 50%

Room temperature.

thermosetting is used

  4,4'-bis-maleimido which was cured at 210 ° C following:% by volume 1.90 g / cm3, 1 MPa 211 MPa

0.57 MPa.

the mechanical strengths

values corresponding to

EXAMPLE 3

  To manufacture a laminate based on a carbon fiber fabric a thermoplastic polyimide prepared according to Example 1 of U.S. patent is used. No. 3,708,458 and a polyimide resin

  thermosetting according to Example 1 of the first fasci-

  published patent document of the R.F.A.

  No. 2,530,571, the imide resins in question forming

the hybrid matrix.

  We make a cast sheet using

  a solution of the hybrid matrix in N-methyl-

  pyrrolidone. The weight ratio of the thermomeric polyimide

  thermosetting poly-imide plastic is 2: 1.

  Prepregs having a resin content of 10% are made by soaking in a solution with

  % of the hybrid matrix in N-methyl-pyrrolidone

  pyrrolidone. The excess resin is allowed to flow and the prepregs are dried at 140 ° C. for 15 minutes in a circulating air oven. The residual content in

solvent is 2.1%.

  Hybrid matrix sheets and prepregs were superimposed in alternate layers, which were prepared as described above, and the assembly was cured for 4 hours in a platen press at a pressure of 4.9 MPa at a temperature which,

  at the beginning, it is 190 C and it grows up to 240 C.

  The laminate has the following properties: Density 1.50 g / cm3 Flexural strength 6.1 MPa

Bending module 666 MPa.

  At 250 C the mechanical resistance is

  still 68% compared to the starting value.

  The term "prepregs" as used herein refers to fibrous materials

prepregs. -

Claims (4)

  1. Composite materials made of fibers, for example glass fibers, carbon fibers, boron fibers or aromatic polyamide fibers, in the form of nonwovens, fabrics or knits, and a non-flammable binder and resistant to high temperatures, materialscharacterized in that they comprise,   as a binder, a hybrid matrix consisting of a macro-   soluble thermoplastic polymer and a thermosetting resin   curable. 2.- Composite mats according to the claim   1, characterized in that the ratio of the thermoset polymer   plastic to the thermosetting resin of the matrix   hybrid is between 95: 5 and 5:95.   3. Composite materials according to the claim   1, characterized in that the thermoplastic component   that the hybrid matrix is a soluble, high temperature resistant macropolymer taken from the group consisting of polysulfones, polyhydantoins, polycarbonates, polyamides, polyimides,   polyamide-imides, polyphenyl-quinoxalines, poly-   benzimidazoles, polyoxadiazoles and polybenzothiazoles xazoles.   4. Composite materials according to the claim   1, characterized in that the thermo-   curable hybrid matrix is a soluble resin,   resistant to high temperatures, taken as a whole   composed of polyesters, epoxides, bisphenols   maleimides and prepolymers with terminal groups   tyléniques. 16. 5.- Composite materials according to claim 1, characterized in that they comprise, as component   thermoplastic of the hybrid matrix, a polyamide-imitation   from which can be obtained from the dianhydride of the acid   benzophenone tetracarboxylic acid, m-aminobenzol   and diamino-diphenylmethane and, as a component   thermosetting, a bis-maleimide of the formula the o 0 he he C C B N - A - N B (I) O 'O'   in which A represents a divalent organic radical containing at least two carbon atoms and B one   following bivalent organic radicals :. H H3C H / H3C IIC 2C'- C -   and H2C 6. Composite materials according to claim 1, characterized in that they comprise, as a component   thermoplastic, a polyether sulphone and, as a   thermosetting, a poly-imidic prepolymer which   can be obtained by reacting a bis-maleimide   to the general formula where C N P. N X / C He O Or o He C -A-N B   C II (I) with a diamine corresponding to the general formula II N - D - NH2 (II)   in which D represents a bi-organic radical   are at least two carbon atoms, the C-11 - C C is the molar ratio between the bis-imide (I) and the diamine   (II) being preferably between 1.2 and 5.   7.- Method of manufacturing composite materials   stents made of fibers, for example glass fibers, carbon fibers, boron fibers or aromatic polyamide fibers, in the form of nonwovens, fabrics or knits, and a matrix   non-flammable hybrid, resistant to high temperatures   , consisting of a thermoplastic macropolymer and a thermosetting resin, characterized in that sheets are alternately superposed   of the hybrid matrix and the fibrous materials   impregnated ("prepregs") of the hybrid matrix, which are low in resin, and the assembly is molded under pressure at high temperatures.