USE OF POLYARYLETHERCETONE SULFONE OR NON-POLYMERIC SULPHONATED ARYLETHERCETONE AS AN AGENT

DISPERSING

FIELD OF THE INVENTION

The present invention relates to the use of a sulfonated polyaryletherketone or, of a sulfonated non-polymeric aryletherketone, as a dispersing agent for polyaryletherketone resin powders, in particular in the manufacture of semi-products comprising a polyaryletherketone resin and fibers of polyaryletherketone. reinforcement.

TECHNICAL BACKGROUND

Composite materials combining a thermoplastic resin with reinforcing fibers have, because of their excellent mechanical properties for a low weight, a great interest in many fields, in particular in the aeronautical and space industry, but also in the automotive industry and sports equipment.

These composite materials are generally manufactured by consolidating semi-finished products made up of reinforcing fibers coated with resin such as prepregs in the form of unidirectional sheets, wicks or woven fabrics.

These semi-products can be obtained by impregnation of the fibers with the resin. There are various processes, in which the resin can be melted, dissolved in a solvent, or else in the form of powder, either in a fluidized bed or dispersed in an aqueous solution. The impregnated fibers are then, where appropriate, freed from the solvent or from the aqueous solution and then heated in order to melt the resin retained and form the semi-product.

For polymers with a high melting point such as polyaryletherketones (PAEK), impregnation via an aqueous dispersion in a bath is advantageous from an economic and environmental point of view. With this technique, it is important to ensure a homogeneous distribution of the resin particles during the impregnation of the fibers.

It is known to include dispersing agents or surfactants in the aqueous dispersion in order to allow the dispersion and to promote this homogeneous distribution, whether with stirring or not. These agents are often composed of a hydrophobic part (fatty chain, aromatic group) and of a hydrophilic part (ethoxylated chain or group

ionic). The ethoxylated chains, such as in particular the polyethylene glycol chains, have low thermal stability.

In the presence of oxygen, they oxidize and form radicals from 200-250 ° C. Under an inert atmosphere, they underwent thermolysis from 350-370 ° C. The radicals generated by these parasitic reactions lead to the degradation of the polymer (branching reactions, presence of insolubles, drop in crystallization temperature, etc.), disrupting the following steps to manufacture the composite and inducing unsatisfactory properties.

Furthermore, document US 2015 / 274588A describes the use of sulfonated PAEK for the sizing of fibers. The sulfonated PAEK is dissolved in hot water and then coated on fibers. The fibers are subjected to a heat treatment to be dried, then to desulfonate the PAEK.

Document US 2004/0131910 describes methods of sulfonating poly-ether-ketone-ketone (PEKK) with hot-fuming sulfuric acid or with chlorosulfuric acid at room temperature.

There is a need to provide homogeneous aqueous dispersions of PAEK for the impregnation of reinforcing fibers, while avoiding deterioration of the thermal stability of the PAEK.

SUMMARY OF THE INVENTION

The invention relates firstly to the use of a sulfonated polyaryletherketone or, of a sulfonated non-polymeric aryletherketone, as a dispersing agent for a powder of polyaryletherketone resin in an aqueous solution.

In some embodiments, the polyaryletherketone is selected from the group consisting of poly-ether-ketones (PEK), poly-ether-ether-ketones (PEEK), poly-ether-ether-ketone-ketones (PEEKK), poly-ether-ketone-ketones (PEKK), poly-ether-ketone-ether-ketone-ketones (PEKEKK), poly-ether-ether-ketone-ether-ketones (PEEKEK), poly-ether-ether ether-ketones (PEEEK), poly-ether-diphenyl-ether-ketones (PEDEK), mixtures thereof and copolymers comprising these, the polyaryletherketone preferably being a poly-ether-ketone-ketone (PEKK) or a poly-ether-ether-ketone (PEEK).

In some embodiments, the sulfonated polyaryletherketone is selected from the group consisting of sulfonated poly-ether-ketones (PEK), sulfonated poly-ether-ether-ketones (PEEK), poly-ether-ether-ketone-ketones ( Sulfonated PEEKK), sulfonated poly-ether-ketone-ketones (PEKK), sulfonated poly-ether-ketone-ether-ketone-ketones (PEKEKK), sulfonated poly-ether-ether-ketone-ether-ketones (PEEKEK) , sulfonated poly-ether-ether-ether-ketones (PEEEK), sulfonated poly-ether-diphenyl-ether-ketones (PEDEK), mixtures thereof and copolymers comprising these.

In some embodiments, the sulfonated non-polymeric aryletherketone is sulfonated 1,4-bis (4-phenoxybenzoyl) benzene.

In some embodiments, the sulfonated polyaryletherketone, or sulfonated non-polymeric aryletherketone, has a degree of sulfonation of 0.01 to 4, preferably 0.01 to 1, and more preferably 0.01 to 0.1. .

In certain embodiments, the sulfonated polyaryletherketone or, the sulfonated non-polymeric aryletherketone, comprises sulfonated groups chosen from sulfonic acid groups and / or sulfonate groups, the molar proportion of sulfonate groups in the sulfonated polyaryletherketone, respectively in the sulfonated polyaryletherketone. sulfonated non-polymeric aryletherketone, with respect to all the sulfonated groups being preferably greater than or equal to 50%, more preferably greater than or equal to 80%.

The invention also relates to a composition comprising a powder of polyaryletherketone resin suspended in an aqueous solution, the composition further comprising a sulfonated polyaryletherketone or, a sulfonated non-polymeric aryletherketone.

In some embodiments, the polyaryletherketone is selected from the group consisting of poly-ether-ketones (PEK), poly-ether-ether-ketones (PEEK), poly-ether-ether-ketone-ketones (PEEKK), poly-ether-ketone-ketones (PEKK), poly-ether-ketone-ether-ketone-ketones (PEKEKK), poly-ether-ether-ketone-ether-ketones (PEEKEK), poly-ether-ether ether-ketones (PEEEK), poly-ether-diphenyl-ether-ketones (PEDEK), mixtures thereof and copolymers comprising these, the polyaryletherketone preferably being a poly-ether-ketone-ketone (PEKK) or a poly-ether-ether-ketone (PEEK).

In some embodiments, the sulfonated polyaryletherketone is selected from the group consisting of sulfonated poly-ether-ketones (PEK), sulfonated poly-ether-ether-ketones (PEEK), poly-ether-ether-ketone-ketones ( Sulfonated PEEKK), sulfonated poly-ether-ketone-ketones (PEKK), sulfonated poly-ether-ketone-ether-ketone-ketones (PEKEKK), sulfonated poly-ether-ether-ketone-ether-ketones (PEEKEK) , sulfonated poly-ether-ether-ether-ketones (PEEEK), poly-ether-diphenyl-ether-ketones

(PEDEK) sulfonates, mixtures thereof and copolymers comprising them. Particularly preferred are sulfonated polyether-ketone ketones (PEKK) and sulfonated poly-ether-ether-ketones (PEEK).

In some embodiments, the sulfonated non-polymeric aryletherketone is sulfonated 1,4-bis (4-phenoxybenzoyl) benzene.

In some embodiments, the sulfonated polyaryletherketone, or sulfonated non-polymeric aryletherketone, has a degree of sulfonation of 0.01 to 4, preferably 0.1 to 1, and more preferably 0.1 to 0.5. .

In certain embodiments, the sulfonated polyaryletherketone or, the sulfonated non-polymeric aryletherketone, comprises sulfonated groups chosen from sulfonic acid groups and / or sulfonate groups, the molar proportion of sulfonate groups in the sulfonated polyaryletherketone, respectively in the sulfonated polyaryletherketone. sulfonated non-polymeric aryletherketone, relative to all the sulfonated groups being preferably greater than or equal to 50%, preferably greater than or equal to 80%.

In some embodiments, the content by weight of sulfonated polyaryletherketone or, of sulfonated non-polymeric aryletherketone, relative to the polyaryletherketone resin powder is from 0.1 to 20%, advantageously from 0.2 to 10%, preferably from 0.5 to 5% and very particularly from 1 to 3%.

The invention also relates to a process for preparing a semi-finished product comprising a polyaryletherketone resin and reinforcing fibers, comprising:

- providing a composition as described above, and impregnating reinforcing fibers with this composition;

- drying the impregnated reinforcing fibers;

- Heating the impregnated reinforcing fibers so as to melt the polyaryletherketone; and

- optionally, a calendering step.

In some embodiments, the reinforcing fibers are carbon fibers.

In certain embodiments, the semi-finished product is chosen from a prepreg or a tape.

The invention also relates to a semi-finished product capable of being prepared according to the process described above.

The invention also relates to the use of a semi-finished product as described above for the manufacture of composite materials.

The present invention overcomes the drawbacks of the state of the art. More particularly, it provides a means of dispersing (suspending) a powder of PAEK in an aqueous solution in a homogeneous manner, while avoiding deterioration of the thermal stability of the PAEK.

This is accomplished through the use of a sulfonated PAEK or, a sulfonated non-polymeric aryletherketone, as a dispersing agent.

The invention can make it possible to dispense with the use of conventional surfactants which are insufficiently thermally stable.

The invention can be implemented with a relatively small amount of sulfonated compound, which makes it possible to limit the problems of porosity inherent in this type of compound. In fact, despite a high thermal stability, these compounds can desulfonate under the conditions of use, which can generate volatiles and thereby increase the porosity.

The invention can make it possible to avoid the use of a sizing of the fibers, the sulphonated PAEK making it possible to promote the bond between the reinforcing fibers and the PAEK matrix.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The invention is now described in more detail and in a nonlimiting manner in the description which follows.

The invention relates to the use of a sulfonated PAEK, or sulfonated non-polymeric aryletherketone, as a dispersing agent for a powder of PAEK resin in an aqueous medium.

PAEK resin

The term “resin” is understood to mean a composition mainly comprising one or more polymers added where appropriate with additives such as fillers and functional additives.

The term “PAEK” is intended to mean polymers comprising units of formulas (-Ar-X-) as well as units of formula (-Ar'-Y-), in which:

- Ar and Ar 'each denote a divalent aromatic radical;

- Ar and Ar 'can be chosen, preferably, from 1, 3-phenylene, 1, 4-phenylene, 4,4'-biphenylene, 1, 4-naphthylene, 1, 5-naphthylene and 2 , 6-naphthylene, optionally substituted;

- X denotes an electron withdrawing group, which may be chosen, preferably, from the carbonyl group and the sulfonyl group;

- Y denotes a group chosen from an oxygen atom, a sulfur atom, an alkylene group, such as in particular -CH2- and isopropylidene.

Among the X units, at least 50 mol%, preferably at least 70 mol% and more particularly, at least 80 mol% of the X units represent a carbonyl group. In some embodiments, all of the X units denote a carbonyl group.

Among the Y units, at least 50 mol%, preferably at least 70 mol% and more particularly at least 80 mol% of the Y units represent an oxygen atom. In some embodiments, all of the Y units denote an oxygen atom.

Thus, in certain embodiments, the PAEK is a polymer comprising, or preferably constituted, of units of formulas (-Ar-CO-) as well as of units of formula (-Ar'-O-), the units Ar and Ar 'being as defined above.

In certain embodiments, the PAEK is a poly-ether-ketone-ketone (PEKK), comprising a succession of repeating units of the type - (An-O-Ar2-CO-Ar3-CO) n -, each An, Ar2 and Ar3 independently representing a divalent aromatic radical, preferably a phenylene.

In the above formula, as in all of the formulas that follow, n represents an integer.

The bonds on either side of each An, Ar2 and Ar3 unit can be of the para, or meta, or ortho type (preferably of the para or meta type).

In certain embodiments, the PEKK comprises a succession of repeating units of the following formula (IA) and / or of the following formula (IB):

(IA)

(IB)

The units of formula (IA) are units derived from isophthalic acid (or units I), while the units of formula (IB) are units derived from terephthalic acid (or units T).

In the PEKK used in the invention, the proportion by weight of T units relative to the sum of T and I units can vary from 0 to 5%; or from 5 to 10%; or from 10 to 15%; or from 15 to 20%; or from 15 to 20%; or from 20 to 25%; or from 25 to 30%; or from 30 to 35%; or from 35 to 40%; or from 40 to 45%; or from 45 to 50%; or from 50 to 55%; or from 55 to 60%; or from 60 to 65%; or from 65 to 70%; or from 70 to 75%; or from 75 to 80%; or from 80 to 85%; or from 85 to 90%; or from 90 to 95%; or 95 to 100%.

Ranges from 35 to 100%, in particular from 55 to 85% and more specifically still from 60 to 80%, are particularly suitable. In all of the ranges stated in the present application, the terminals are included unless otherwise specified.

In certain embodiments, the PAEK is a poly-ether-ether-ketone (PEEK), comprising a succession of repeating units of the type - (An-O-Ar2-0-Ar3-C0) n -, each An, Ar2 and Ar3 independently representing a divalent aromatic radical, preferably a phenylene.

The bonds on either side of each An, Ar2 and Ar3 unit can be of the para, or meta, or ortho type (preferably of the para or meta type).

In certain embodiments, the PEEK comprises a succession of repeated units of formula (II):

and / or a succession of repeated units of formula (III):

and / or a succession of repeated units of formula (IV):

(IV)
and / or a succession of repeated units of formula (V):

(V)

In certain embodiments, the PAEK is a polyether-ketone (PEK), comprising a succession of repeated units of the - (An-0-Ar2-CO) n - type, each An and Ar2 independently representing a radical divalent aromatic, preferably phenylene.

The bonds on either side of each An and Ar2 unit can be of the para, or meta, or ortho type (preferably of the para or meta type).

In certain embodiments, the PEK comprises a succession of repeated units of formula (VI):

(VI)
In certain embodiments, the PEK comprises a succession of repeated units of formula (VII):

In this formula, just like in the following formulas, x and y represent whole numbers.

In certain embodiments, the PEK comprises a succession of repeated units of formula (VIII):

In certain embodiments, the PAEK is a poly-ether-ether-ketone-ketone (PEEKK), comprising a succession of repeating units of the - (Ari-0-Ar2-0-Ar3-C0-Ar 4 -C0) type n -, each An, Ar2, Ar3 and Ar 4 independently representing a divalent aromatic radical, preferably a phenylene.

The bonds on either side of each An, Ar2, Ar3 and Ar 4 unit can be of the para, or meta, or ortho type (preferably of the para or meta type).

In certain embodiments, the PEEKK comprises a succession of repeating units of formula (IX):

In certain embodiments, the PAEK is a poly-ether-ether-ether-ketone (PEEEK), comprising a succession of repeating units of the - (Ari-0-Ar2-0-Ar3-0-Ar 4 -C0) type n -, each An, Ar2, Ar3 and Ar 4 independently representing a divalent aromatic radical, preferably a phenylene.

The bonds on either side of each An, Ar2, Ar3 and Ar 4 unit can be of the para, or meta, or ortho type (preferably of the para or meta type).

In certain embodiments, the PEEEK comprises a succession of repeated units of formula (X):

In certain embodiments, the PAEK is a poly-ether-ketone-ether-ketone-ketone (PEKEKK), comprising a succession of repeating units of the type - (An-0-Ar2-C0-Ar3-0-Ar 4 - C0-Ar5-C0) n -, each An, Ar2, Ar3, Ar 4 and Ars independently representing a divalent aromatic radical, preferably a phenylene.

The bonds on either side of each An, Ar2, Ar3, Ar 4 and Ars unit can be of the para, or meta, or ortho type (preferably of the para or meta type).

In certain embodiments, the PAEK is a poly-ether-ether-ketone-ether-ketone (PEEKEK), comprising a succession of repeating units of type - (Ari-0-Ar2-0-Ar3-C0-Ar 4 - 0-Ar5-C0) n -, each An, Ar2, Ar3, Ar 4 and Ars independently representing a divalent aromatic radical, preferably a phenylene.

The bonds on either side of each An, Ar2, Ar3, Ar 4 and Ars unit can be of the para, or meta, or ortho type (preferably of the para or meta type).

In certain embodiments, the PAEK is according to the most general formula given below, in which certain Ar and / or Ar 'units represent a divalent radical derived from diphenyl or biphenol.

In certain embodiments, the PAEK is a poly-ether-diphenyl-ether-ketone (PEDEK), comprising a succession of repeating units of type - (An-0-D-0-Ar2-C0) n -, each An and Ar2 independently representing a divalent aromatic radical, preferably a phenylene, and D representing a divalent radical derived from diphenyl.

The bonds on either side of each An and Ar2 unit can be of the para, or meta, or ortho type (preferably of the para or meta type).

In certain embodiments, the PEDEK comprises a succession of repeated units of formula (XI):

Mixtures of the preceding PAEKs can also be used, as well as copolymers of the preceding PAEKs.

PEEK and PEKK as well as their mixtures are particularly preferred.

The PAEK resin can comprise one or more additional polymers not belonging to the PAEK family.

Preferably, the content by mass of PAEK in the PAEK resin is greater than or equal to 50%, preferably 60%, more preferably 70%, more preferably 80% and more preferably 90%.

In some embodiments, the PAEK resin consists essentially of one or more PAEKs.

In certain embodiments, the PAEK resin comprises PEKK, the content by weight of PEKK in the PAEK resin being greater than or equal to 50%, preferably 60%, more preferably 70%, more preferably 80 % and more preferably 90%.

In some embodiments, the PAEK resin consists essentially of PEKK.

The resin can include one or more phosphates or phosphate salts, to improve the stability of the PAEK in the molten state.

The resin can include additives such as fillers and functional additives. It is also possible to dispense with fillers and / or to dispense with functional additives.

Non-polymeric aryletherketone

By “non-polymeric aryletherketone” is meant a molecule comprising at least one residue of formula: (-Ar-O-) as well as at least one residue of formula: (-Ar'-C (O) -), in which:

- Ar and Ar 'each denote a divalent aromatic radical; and,

- Ar and Ar 'can be chosen independently, preferably, from 1, 3-phenylene, 1, 4-phenylene, 4,4'-biphenylene, 1, 4-naphthylene, 1, 5-naphthylene and 2,6-naphthylene, optionally substituted;

said molecule being non-polymer, that is to say not comprising a repeating unit.

In some embodiments, Ar and Ar 'independently represent a phenylene radical.

The bonds on either side of Ar and Ar 'can be independently of the para, or meta, or ortho type. Preferably, the bonds on either side of Ar and Ar ′ can be independently of the para type, or of the meta type.

In certain embodiments, the non-polymeric aryletherketone can in particular be a molecule comprising at least one residue of formula: (-O-An-C (O) -), in which:

- An denotes a divalent aromatic radical; and,

- An can be chosen, preferably, from 1, 3-phenylene, 1, 4-phenylene, 4,4'-biphenylene, 1, 4-naphthylene, 1, 5-naphthylene and 2,6- naphthylene, optionally substituted; and, said molecule being non-polymer, that is to say not comprising a repeating unit.

In some embodiments, An represents a phenylene radical.

The bonds on either side of An can be of the para, or meta, or ortho type. Preferably, the bonds on either side of An can be of the para type, or of the meta type.

In certain embodiments, the non-polymeric aryletherketone can in particular be a molecule of formula:

Aro-0-An-C (0) -Ar2-C (0) -Ar3-0-Ar 4 , in which:

- Aro and Ar 4 each represent a monovalent aromatic radical, preferably chosen independently from phenyl and naphthyl;

- An, Ar2 and Ar3 each represent a divalent aromatic radical, preferably chosen independently from 1, 3-phenylene, 1, 4-phenylene, 4,4'-biphenylene, 1, 4-naphthylene, 1 , 5-naphthylene and 2,6-naphthylene, optionally substituted.

In certain embodiments, Aro and Ar 4 represent a phenyl radical and An, Ar2 and Ar3 each represent a phenylene radical.

The bonds on either side of An, Ar2 and Ar3 can be of the para, or meta, or ortho type. Preferably, the bonds on either side of An Ar2 and Ar3 can be of the para type, or of the meta type.

In a particular embodiment, the non-polymer aryletherketone is 1, 4-bis (4-phenoxybenzoyl) benzene.

Sulfonated PAEK and non-polymeric aryletherketone

The term “sulfonated” is understood to mean that the PAEK or non-polymeric aryletherketone comprises as substituent (s) at least one group which is designated here “sulfonated group”, that is to say a sulfonic acid group. of formula -SO3H or a sulfonate group of formula SO3M where M + represents a monovalent cation. Preferably, M represents the sodium cation (Na) or the potassium cation (K).

The entire description of the PAEKs given above with regard to the resin applies in the same way to the sulfonated PAEK.

The entire description of the non-polymeric aryletherketones given above applies in the same way to the sulfonated non-polymeric aryletherketones.

In particular embodiments, the sulfonated PAEK can be a sulfonated PEEK (as described above) or a sulfonated PEKK (as described above).

The sulfonated PAEK comprises a number of repeat units greater than or equal to 2, preferably greater than or equal to 10, more preferably greater than or equal to 100.

The number-average molecular mass of the sulfonated PAEK is preferably from 1500 to 30,000 g / mol, more preferably from 5,000 to 20,000 g / mol, and more preferably from 10,000 to 20,000 g / mol. The fact of using a polymer with a target molar mass makes it possible to modulate the viscosity of the dispersion in order to limit, for example, sedimentation or to facilitate the entrainment of the powder by the fibers.

In sulfonated PAEK, sulfonated groups can be present as substituents of hydrogen atoms at any position of the molecule.

In particular, the sulfonated groups can be present as substituents of hydrogen atoms on one or more Ar and Ar 'units as described above.

Preferably, the sulphonated groups are present on one or more Ar and Ar 'units linked to an -O- ether unit.

An example of a sulfonated PAEK is the sulfonated PEKK of generic formula

wherein a, b and c each independently represent 0 or an integer. It is understood that, in the preceding formula, the sulphonic acid groups can also be replaced in whole or in part by sulphonate groups.

The sulfonated PAEK can be prepared by sulfonation of the corresponding PAEK or by polymerization of sulfonated monomers, or mixtures of sulfonated and non-sulfonated monomers. The sulphonation reaction of PAEK can be carried out for example by placing the PAEK in the presence of fuming sulfuric acid (H2S0 4 + SO3). The temperature for carrying out the reaction can in particular be from 20 to 90 ° C, preferably from 20 to 60 ° C. The duration of the reaction can in particular be from 0.5 to 24 h, preferably from 1 to 8. h. The concentration of PAEK in the acid is preferably 1 to 40%, more preferably 5 to 35%, and more preferably 10 to 30% (by weight).

Alternatively, the sulfonation reaction can be carried out under milder conditions, by reacting the PAEK in acid

chlorosulfuric (CISO3H). The temperature for carrying out the reaction can in particular be from 0 0 C to 50 0 C, preferably from 10 to 25 0 C. The duration of the reaction can in particular be from 1 hour to 12 hours, preferably from 2 hours to 10 hours. The concentration of PAEK in the acid is preferably 1 to 40%, more preferably 5 to 35%, and more preferably 10 to 30% (by weight).

After the sulfonation reaction, the product of interest can be collected, for example by pouring it into cold water so as to precipitate it. It can be washed in cold water to remove excess acid and dried.

The above reactions make it possible to graft sulfonic acid groups onto the molecules.

It is then possible to convert all or part of these sulphonic acid groups into sulphonate groups, by bringing them into contact with a base, such as sodium or potassium hydroxide (neutralization reaction).

The temperature for carrying out the neutralization reaction can in particular be from 5 to 95 ° C, preferably from 50 to 80 ° C. The duration of the reaction can in particular be from 1 to 50 h, preferably from 1 to 8. h. The concentration of the sulfonated PAEK in the base solution can be in particular from 5 to 50% by weight, and preferably from 10 to 30% by weight.

The sulfonated PAEK can be characterized by its degree of sulfonation. The degree of sulfonation corresponds to the average number of sulfonated groups per repeat unit in the polymer. The higher the degree of sulfonation, the more soluble the sulfonated PAEK is in water. The solubility also depends on the nature of the PAEK, on ​​its molar mass and on its crystallinity in particular. It is generally desirable to use the minimum degree of sulfonation allowing the sulfonated PAEK to be solubilized in water.

Depending on the nature of the PAEK and depending on the degree of sulfonation, some sulfonated PAEKs are soluble in water at room temperature, others only at higher temperature, for example 30, or 40 or 50 ° C.

Preferably, the sulfonated PAEK is soluble in water at ambient temperature (20 ° C.), which facilitates the management of the impregnation bath and prevents a loss of water inducing a variation in viscosity of the bath.

The degree of sulfonation can be controlled by influencing the conditions of the sulfonation reaction, including reaction time, temperature and sulfonate ion concentration.

The articles Sulfonated Poly (aryl ether ketone) s by Ulrich and Rafler in Die Angewandte Makromolekulare Chemie 263: 71 -78 (1998) and Sulfonated

Poly (ether ketone ketone) lonomers as Proton Exchange Membranes, by Swier et al. in Polymer Engineering and Science, DOI 10.1002 / pen.20361 (2005) describe examples of sulfonation of PAEK as well as possible adjustment of the reaction conditions.

The degree of sulfonation can be determined by acid-base titration, for example with sodium hydroxide. For example, one can take a test portion of 1 to 2 g of sulfonated PAEK, dissolve it in 60 mL of pure water (for example of HPLC quality) while stirring for example 15 minutes, then carry out a dosage by soda at 0.01 N.

The degree of sulfonation of the sulfonated PAEK may in particular be from 0.01 to 0.05; or from 0.05 to 0.1; or from 0.1 to 0.2; or from 0.2 to 0.5; or from 0.5 to 1; or from 1 to 2; or from 2 to 3; or 3 to 4. Ranges of 0.1 to 1 and 0.1 to 0.5 may be particularly suitable.

The degree of neutralization of the sulfonated groups corresponds to the molar proportion of sulfonate groups relative to all of the sulfonated groups.

The degree of neutralization can be controlled by acting on the amount of base brought into contact with the sulfonated PAEK. Preferably, a stoichiometric amount of base, or slightly less (0.98 equivalent), relative to the sulfonated groups is used.

The degree of neutralization can be determined by titration by measuring the residual acidity with sodium hydroxide.

Preferably, the degree of neutralization of the sulfonated PAEK is from 50% to 100%, more preferably from 75% to 100% and more preferably from 95% to 100%.

Neutralization makes it possible to limit the degradation of the PAEK resin by the sulfonated PAEK.

The mixtures of different sulfonated PAEKs are considered in the present description as a sulfonated PAEK.

The present inventors have further found that the sulfonation of PAEKs described above can be applied in exactly the same way to a non-polymeric aryletherketone. In particular, it is possible to produce sulfonated 1,4-bis (4-phenoxybenzoyl) benzene in this way.

By way of example, this sulfonated 1, 4-bis (4-phenoxybenzoyl) benzene can correspond to the following formula (XII):

wherein each X independently represents a hydrogen atom or a sulfonated group, at least one of the two Xs representing a sulfonated group.

Preferably, each X represents a sulfonated group.

Resin powder suspension

According to the invention, a composition is prepared by adding the PAEK resin powder to an aqueous solution so as to form a suspension or dispersion.

The term “suspension” or “dispersion” is understood to mean a heterogeneous composition comprising a liquid phase and a solid phase. The liquid phase is aqueous and contains the sulfonated PAEK or, the sulfonated non-polymeric aryletherketone, as well as other additives, if desired. The solid phase comprises or consists essentially of the PAEK resin powder.

In order to ensure optimum homogeneity of the suspension, and a good subsequent impregnation of the fibers, it is preferred that the resin powder is finely divided. More specifically, it is preferred that the PAEK resin powder has a median diameter Dv50 ranging from 1 to 300 μm, preferably from 5 to 100 μm and very particularly from 10 to 50 μm, as measured according to the ISO 13 320 standard. .

Preferably, the powder content of PAEK resin or, of sulfonated non-polymeric aryletherketone, in this composition is from 1 to 50%, preferably from 10 to 40% and very particularly from 25 to 35% by weight (for relative to the weight of the total composition).

Sulfonated PAEK, or sulfonated non-polymeric aryletherketone, is used as a dispersing agent, or surfactant, in the composition. The sulfonated PAEK, or sulfonated non-polymeric aryletherketone, is present in the aqueous phase of the composition.

In some embodiments, the proportion by weight of sulfonated PAEK or, of sulfonated non-polymeric aryletherketone, relative to the sum of sulfonated PAEK and PAEK resin, or respectively relative to the sum of sulfonated non-polymeric aryletherketone and PAEK resin, is 0.1 to 0.2%; or from 0.2 to 0.5%; or from 0.5 to 1%; or from 1 to 2%; or from 1 to 5%; or from 5 to 10%. A range of 0.5 to 5% is particularly suitable.

The optimum mass proportion can be chosen as a function of the amount of powder to be dispersed, its particle size and its surface appearance.

The sulfonated PAEK may or may not be of the same nature as the PAEK of the resin.

The aqueous phase of the composition may optionally comprise one or more other surfactants other than sulfonated PAEK or sulfonated non-polymeric aryletherketone. However, it is preferred that no other surfactant is present to provide the dispersing function.

By “use as a dispersing agent” is meant that the sulfonated PAEK or the sulfonated non-polymeric aryletherketone makes it possible to improve the dispersion of the PAEK resin powder in the aqueous solution, and more particularly to reduce the dispersion time. Thus, when one introduces into an aqueous solution of sulfonated PAEK at 25 ° C, or into an aqueous solution of non-polymeric sulfonated aryletherketone of 25 ° C, an amount of 20% by weight relative to the weight of the finished dispersion of PAEK powder having an average Dv 50 of 20 μm and that this powder is dispersed in the solution with moderate stirring, the presence of the sulfonated PAEK, respectively of the sulfonated non-polymeric aryletherketone, makes it possible to obtain a homogeneous dispersion in a time less than 3 h, preferably less than 2 h, whereas,

The aqueous phase of the dispersion can, if necessary, comprise other additives such as thickening agents, anti-foaming agents, biocidal agents. Preferably, in order to limit the presence of additives in the semi-finished products and the associated potential problems, the total amount of other additives does not exceed 4% by weight, in particular 3% and very particularly 2% by weight or even 1. % by weight of the total composition.

More preferably, the aqueous phase of the dispersion does not contain other additives, and in particular no thickening agents.

The aqueous phase of the dispersion consists mainly of water. The aqueous phase of the dispersion comprises at least 60%, preferably 70%, more preferably at least 80% and very particularly at least 90% by weight of water. The water used to prepare the dispersion is preferably demineralized water.

The dispersion and more particularly its aqueous phase may further comprise one or more volatile organic compounds.

By “volatile organic compound” is meant a compound containing at least the element carbon and one or more of the elements chosen from hydrogen, halogens, oxygen, sulfur, phosphorus, silicon and nitrogen, with the exception of carbon oxides and carbonates and bicarbonates, the compound having a boiling point at atmospheric pressure less than 200 ° C, and preferably less than 150 ° C, more preferably less than 120 ° C and all particularly below 100 ° C.

These volatile organic compounds, soluble in water under the conditions of use, can be chosen in particular from the families of alcohols, ketones, aldehydes, esters of carboxylic acids, glycols and ethers.

In certain embodiments, as volatile organic compound, an alcohol chosen from among ethanol, isopropanol, n-propanol, n-butanol, 2-butanol, terf-butanol, 1-methoxy is used. -2-propanol, 1 -ethoxy-2-propanol and their mixtures, a glycol chosen from ethylene glycol, propylene glycol and their mixtures, a ketone chosen such as acetone, an ether or else an ester of carboxylic acid chosen from methyl acetate, ethyl acetate and propyl acetate, and mixtures thereof.

Particularly preferred are volatile organic compounds forming an azeotrope with water, facilitating their elimination, such as ethanol, methyl acetate, propyl acetate and mixtures thereof.

The addition of such volatile organic compounds to the aqueous phase can make it possible to reduce the content of surfactant required to stabilize the PAEK resin in the dispersion and / or to increase the viscosity of the dispersion while ensuring better wetting of the dispersed particles. Their volatility ensures that they do not remain in the resin, unlike the usual non-volatile additives which then run the risk of being broken down into species reactive to the melting of the resin.

The aqueous phase of the dispersion may preferably comprise from 0 to 50%, more preferably from 1 to 40%, or from 5 to 30%, or from 10 to 25% by weight of one or more volatile compounds. The content of these compounds is adjusted to avoid precipitating the surfactant.

The dispersion obtained preferably has a dynamic viscosity, as measured at 25 ° C under a shear stress of 6.8 s-1 on a Brookfield DVT2T Extra viscometer, from 0.1 Pa-s to 20 Pa-s, in

in particular from 0.1 to 5 Pa-s, in particular from 0.3 to 3 Pa-s and very particularly from 0.5 to 2 Pa-s.

The dispersion can be carried out in a manner known per se. It can for example be prepared by introducing the required quantity of water into a container of suitable volume and fitted with an appropriate stirring device, then adding the dispersing agent as well as the other additive (s), if necessary. . If necessary, the mixture is stirred until a homogeneous solution is obtained. The PAEK resin powder is then introduced into the aqueous solution, followed by stirring until a stable dispersion is obtained.

The additions and mixtures for preparing the dispersion can be carried out in particular at a temperature of 10 to 95 ° C, preferably 20 to 60 ° C. The choice of a suitable temperature can be made in particular according to the solubility of the sulphonated PAEK. or, sulfonated non-polymeric aryletherketone, in water. It is preferable to use a relatively high temperature if the sulfonated PAEK, respectively the sulfonated non-polymeric aryletherketone, is relatively sparingly soluble in water, whereas a lower temperature and in particular room temperature may be suitable if the solubility of the Sulfonated PAEK, respectively sulfonated non-polymeric aryletherketone, in water is high.

Process for preparing a semi-finished product

The term “semi-finished product” is understood to mean a product comprising a resin and reinforcing fibers, which is used as an intermediate product in the manufacture of composite materials. The semi-products can in particular be prepregs in the form of unidirectional layers of wicks, of woven fabrics, or else of fiber-matrix mixtures.

The reinforcing fibers used for the manufacture of semi-finished products can be chosen from all the fibers capable of being used as reinforcement in the manufacture of parts made of composite materials.

Thus, it may in particular be glass fibers, quartz fibers, carbon fibers, graphite fibers, silica fibers, metal fibers such as steel fibers, aluminum fibers or boron fibers, ceramic fibers such as silicon carbide or boron carbide fibers, synthetic organic fibers such as aramid fibers or poly (p-phenylene benzobisoxazole) fibers, better known by the acronym PBO, or else PAEK fibers, or alternatively mixtures of such fibers.

Preferably, they are carbon fibers or glass fibers, and more particularly carbon fibers.

The fibers are preferably unsized. When they are sized, the size is preferably suitable for the matrix, in particular in that it does not cause degradation products that are harmful to the matrix.

The reinforcing fibers used are generally continuous.

Preferably, they are in the form of unidirectional fibers, for example in the form of threads grouping together several thousand elementary filaments (typically from 3000 to 48000) measuring, for example, from 6 to 10 μm in diameter for carbon fibers. This type of fiber is known by the name of rovings (in English: "rovings").

The fibers can nevertheless also be organized in a different manner, for example in the form of a mat, or alternatively of textiles obtained by weaving rovings.

The semi-products according to the invention can be manufactured in a conventional manner, by using the dispersion as described above.

More specifically, they can be obtained by introducing and circulating the reinforcing fibers in a dispersion bath as described above. The fibers impregnated with PAEK resin powder are then taken out of the bath and freed from water, for example by drying in an infrared oven. The dried impregnated fibers are then heated until the resin melts, in order to allow the fibers to be coated with the PAEK resin. The coated fibers obtained are then, where appropriate, shaped, for example by calendering. This step can make it possible to texture and ensure the sizing of the semi-finished product.

Preferably, the semi-finished products according to the invention comprise from 1 to 99% by weight, preferably from 30 to 90%, in particular from 50 to 80% by weight, and in particular from 60 to 70% by weight of fibers reinforcement.

The semi-finished products obtained according to this can be used in particular for the manufacture of composite parts.

The composite parts are obtained for example by first manufacturing a preform, in particular by placing or draping the pre-impregnated semi-products in a mold. The composite part is then obtained by consolidation, a step during which the preform is heated, generally under pressure in an autoclave, so as to assemble the semi-products by fusion. Preferably, the semi-finished products manufactured according to the invention can be consolidated outside an autoclave, for example in a vacuum tank placed in an oven.

The semi-finished products manufactured according to the process of the invention are characterized in particular by a resin whose viscosity changes little despite the high temperatures required for their manufacture in order to melt the resin.

In the manufacturing processes for composite parts, the semi-finished products are subjected to different thermal cycles under pressure or under vacuum in order to assemble them together to form the composite part and / or to shape it.

The composite products manufactured according to the process of the invention are characterized in particular by a resin whose viscosity has changed little despite the high temperatures required for their manufacture.

During these steps, it is important that the viscosity of the die is not too high, in order to ensure that the semi-finished products conform to the shapes of the mold. The viscosity of the matrix also makes it possible to ensure good flow during consolidation and thus to avoid surface defects such as wrinkles.

The semi-finished products can then be assembled, for example by manual or automated draping or by robotized depositing, and shaped by consolidation, for the manufacture of composite parts. The composite parts thus manufactured can be further processed, in order to obtain complex composite part assemblies. Thus, it is possible to co-consolidate composite parts, a process generally carried out in an autoclave by means of a new thermal cycle, or to come and weld parts to each other by local heating.

EXAMPLES

The following examples illustrate the invention without limiting it.

Example 1 - Preparation of an unneutralized S-PEKK

A PEKK produced by Arkema, reference Kepstan® 6004 PF (10 g), having an MVI (melt volume index) of 23.4cm 3 / 10min (at 380 ° C under a load of 1 kg), as well as CISO3H (38 , 8 g) are brought together at 0 ° C. The mixture is then stirred vigorously and heated at 50 ° C. for 6 hours. The mixture is then cooled to 0 ° C and dichloromethane (50 mL) is added to thin the mixture. Then the excess acid is quenched with water (100 mL). A solid forms, it is filtered and washed with copious amounts of water to remove the residual acid. Finally, the solid is dried in an oven under vacuum for 2 hours at 120 ° C.

By acid-base determination with sodium hydroxide, a degree of sulfonation of 0.38 is determined.

Example 2 - Preparation of an unneutralized S-oPEKK

A PEKK oligomer (10 g) with a molecular mass of 2600 g / mol is sulfonated according to the conditions of Example 1.

By assaying with sodium hydroxide, a degree of sulfonation of

0.21.

The same protocol can be used with 1, 4-bis (4-phenoxybenzoyl) benzene. Note that at room temperature, 1, 4-bis (4-phenoxybenzoyl) sulfonated benzene with a degree of sulfonation of 2 is not soluble in water but is dispersible in water with stirring.

Example 3 - Preparation of a neutralized sulfonated oligomer S-oPEKK-Na

From the product of Example 2, the degree of sulfonation is determined by acid-base assay, and the neutralized sulfonated PEKK is prepared by reacting the sulfonated oligomer with an equivalent of sodium hydroxide relative to the sulfonic functions in reflux water.

Example 4 - Preparation of an unneutralized S-PEEK

A PEEK produced by Victrex (grade 150G, 10 g), having an MVI (melt volume index) of 49cm 3 / 10min (at 380 ° C under a load of 5kg), as well as CISO3H (38.8 g) are put in the presence at 0 ° C. The mixture is then stirred vigorously and heated at 50 ° C for 6 hours. The mixture is then cooled to 0 ° C and dichloromethane (50 mL) is added to fluidify the mixture. Then the excess acid is quenched with water (100 mL). A solid forms, it is filtered and washed with copious amounts of water to remove the residual acid. Finally, the solid is dried in an oven under vacuum for 2 hours at 120 ° C.

By acid-base determination with sodium hydroxide, a degree of sulfonation of 1.13 is determined.

Example 5 - Preparation of a neutralized S-PEEK

From the product of Example 4, the degree of sulfonation is determined by acid-base assay, and the neutralized sulfonated PEEK is prepared by reacting it with an equivalent of sodium hydroxide relative to the sulfonic functions in refluxed water. .

Example 6 - Dispersion properties and thermal stability

PEKK powder dispersions were prepared. The PEKK used is supplied by Arkema under the reference 7002 PT. The Dv50 of the powder is approximately 20 µm.

The following mixtures were thus prepared, then heated to reflux:

- A (comparative): PEKK 7002PT (1 g) + water (9 g).

- B (comparative): Brij® S100 surfactant from Sigma Aldrich (0.01 g) + PEKK 7002PT (0.99 g) + water (9 g).

- C: S-oPEKK (0.01 g) + PEKK 7002PT (0.99 g) + water (9 g).

- D: S-oPEKK (0.05 g) + PEKK 7002PT (0.95 g) + water (9 g).

- E: S-oPEKK Na (0.05 g) + PEKK 7002PT (0.95 g) + water (9 g).

- F: S-PEEK (0.05 g) + PEKK 7002PT (0.95 g) + water (9 g).

- G: S-PEEK Na (0.05 g) + PEKK 7002PT (0.95 g) + water (9 g).

The quality of the dispersions was studied visually, in a pillbox. A dispersion is considered good if the mixture is fluid, and little or no PEKK powder binds to the walls of the pillbox (except liquid phase) after stirring. It is judged to be fair if the mixture is fluid but a significant amount of PEKK powder attaches to the walls of the pillbox (excluding the liquid phase) after stirring. No dispersion is considered to be obtained if the mixture is thick, and demixing is observed, with the presence of non-wet PEKK residues. It is noted that the dispersion time is less than 2 h when the aqueous solution contains 1% by weight of sulfonated PAEK and less than 1 h when it contains 5% by weight of sulfonated PAEK.

Then, the water of the samples was evaporated on a rotary evaporator and the obtained solids dried under vacuum at 120 ° C for 2 hours. The crystallization temperature of each material after 30 minutes at 380 ° C was then measured. This is in fact impacted by structural changes in PEKK.

A decrease in this temperature is explained either by significant chemical modifications of the polymer or by chain extension reactions associated, for example, with branching phenomena.

The results are summarized in the table below:

It is also observed that a PEKK impregnated by means of a dispersion comprising one of the sulphonated PAEKs prepared as a dispersing agent has a thermal stability greater than that of PEKK impregnated with 1% of commercial surfacta
CLAIMS

1. Use of a sulfonated polyaryletherketone or, a sulfonated non-polymeric aryletherketone, as a dispersing agent for a polyaryletherketone resin powder in an aqueous solution.

2. Use according to claim 1, wherein the polyaryletherketone is selected from the group consisting of polyether-ketones (PEK), poly-ether-ether-ketones (PEEK), poly-ether-ether-ketone-ketones. (PEEKK), poly-ether-ketone-ketones (PEKK), poly-ether-ketone-ether-ketone-ketones (PEKEKK), poly-ether-ether-ketone-ether-ketones (PEEKEK), poly -ether-ether-ether-ketones (PEEEK), poly-ether-diphenyl-ether-ketones (PEDEK), mixtures thereof and copolymers comprising these, the polyaryletherketone preferably being a poly-ether-ketone-ketone (PEKK).

3. Use according to claim 1 or 2, wherein the sulfonated polyaryletherketone is selected from the group consisting of sulfonated poly-ether-ketones (PEK), sulfonated poly-ether-ether-ketones (PEEK), poly-ether- sulfonated ether-ketone-ketones (PEEKK), sulfonated poly-ether-ketone-ketones (PEKK), poly-ether-ketone-ether-ketone-ketones

(PEKEKK) sulfonated poly-ether-ether-ketone-ether-ketones (PEEKEK) sulfonated, poly-ether-ether-ether-ketones (PEEEK) sulfonated, poly-ether-diphenyl-ether-ketone

(PEDEK) sulfonates, mixtures thereof and copolymers comprising them.

4. Use according to claim 1 or claim 2, wherein the sulfonated non-polymeric aryletherketone is sulfonated 1,4-bis (4-phenoxybenzoyl) benzene.

5. Use according to one of claims 1 to 4, wherein the sulfonated polyaryletherketone or, the sulfonated non-polymeric aryletherketone, comprises a degree of sulfonation of 0.01 to 4, preferably 0.1 to 1 and preferably again from 0.1 to 0.5.

6. Use according to one of claims 1 to 5, in which the sulfonated polyaryletherketone or the sulfonated non-polymeric aryletherketone comprises sulfonated groups chosen from sulfonic acid groups and / or sulfonate groups, the molar proportion of sulfonate groups. in sulfonated polyaryletherketone or, respectively, sulfonated non-polymeric aryletherketone, with respect to all the sulfonated groups being preferably greater than or equal to 50%, more preferably greater than or equal to 80%.

7. A composition comprising a powder of polyaryletherketone resin suspended in an aqueous solution, the composition further comprising a sulfonated polyaryletherketone or, a sulfonated non-polymeric aryletherketone.

8. The composition of claim 7, wherein the polyaryletherketone is selected from the group consisting of polyether-ketones (PEK), poly-ether-ether-ketones (PEEK), poly-ether-ether-ketone-ketones. (PEEKK), poly-ether-ketone-ketones (PEKK), poly-ether-ketone-ether-ketone-ketones (PEKEKK), poly-ether-ether-ketone-ether-ketones (PEEKEK), poly -ether-ether-ether-ketones (PEEEK), poly-ether-diphenyl-ether-ketones (PEDEK), mixtures thereof and copolymers comprising these, the polyaryletherketone preferably being a poly-ether-ketone-ketone (PEKK).

9. A composition according to claim 7 or claim 8, wherein the sulfonated polyaryletherketone is selected from the group consisting of sulfonated poly-ether-ketones (PEK), sulfonated poly-ether-ether-ketones (PEEK), poly- sulfonated ether-ether-ketone-ketones (PEEKK), sulfonated poly-ether-ketone-ketones (PEKK), sulfonated poly-ether-ketone-ether-ketone-ketones (PEKEKK), sulfonated poly-ether-ether-ketone sulfonated ether-ketones (PEEKEK), poly-ether-ether-ether-ketones

(PEEEK) sulfonates, sulfonated poly-ether-diphenyl-ether-ketones (PEDEK), mixtures thereof and copolymers comprising thereof.

10. A composition according to claim 7 or claim 8, wherein the sulfonated non-polymeric aryletherketone is sulfonated 1,4-bis (4-phenoxybenzoyl) benzene.

11. Composition according to one of claims 7 to 10, in which the sulfonated polyaryletherketone or, the sulfonated non-polymeric aryletherketone, comprises a degree of sulfonation of 0.01 to 4, preferably from 0.01 to 1 and preferably again from 0.1 to 0.5.

12. Composition according to one of claims 7 to 11, in which the sulfonated polyaryletherketone or, the sulfonated non-polymeric aryletherketone, contains sulfonated groups chosen from sulfonic acid groups and / or sulfonate groups, the molar proportion of sulfonate groups. in sulfonated polyaryletherketone or, respectively in sulfonated non-polymeric aryletherketone, with respect to all the sulfonated groups being preferably greater than or equal to 50%, preferably greater than or equal to 80%.

13. Composition according to one of claims 7 to 12, wherein the mass content of sulfonated polyaryletherketone or, of sulfonated non-polymeric aryletherketone, relative to the polyaryletherketone resin powder is from 0.1 to 20%, preferably of 0.5 to 5%.

14. A process for preparing a semi-finished product comprising a polyaryletherketone resin and reinforcing fibers, comprising:

- the supply of a composition according to one of claims 7 to 13, and the impregnation of reinforcing fibers with this composition;

- drying the impregnated reinforcing fibers;

- Heating the impregnated reinforcing fibers so as to melt the polyaryletherketone; and

- optionally, a calendering step.

15. The preparation process according to claim 14, wherein the reinforcing fibers are carbon fibers.

16. Preparation process according to claim 14 or 15, in which the semi-finished product is chosen from a prepreg or a tape.

17. Semi-finished product capable of being prepared according to the process of one of claims 14 to 16.

18. Use of a semi-finished product according to claim 17 for the manufacture of composite materials.