[Field of the Invention]

[001] The invention relates to a syrup (meth) acrylic viscous liquid, a method for impregnating a fibrous substrate with said syrup, a process for polymerizing said syrup and a composite material obtained after polymerization of said prepreg substrate with said syrup.

[002] In particular, the present invention relates to a syrup (meth) acrylic viscous liquid mainly comprising methacrylic or acrylic components, an initiator to start the polymerization at low temperature and an accelerator. The invention further relates to an industrial process for impregnating a fibrous substrate or long fibers with such a viscous syrup. Finally, the invention relates to a manufacturing method of three-dimensional composite parts or mechanical or structured objects by impregnating a fibrous substrate with such a syrup (meth) acrylic viscous liquid and then polymerizing said liquid syrup. Such three-dimensional composite parts are intended to be used in various fields such as aerospace, automotive, construction, or rail, for example.

[Prior Art]

[003] The mechanical parts which must take high stresses during use are largely made of composite materials. A composite material is a macroscopic combination of two immiscible materials or more. The composite material consists of at least one material which forms the matrix, that is to say a continuous phase ensuring the cohesion of the structure, and a reinforcing material.

[004] The goal, when using a composite material is to obtain performances that are not available with each of its components when they are used separately.

Therefore, composite materials are widely used in many industrial sectors such as for example the construction, automotive, aerospace, transportation, leisure, electronics and sports, especially because of their better mechanical performance ( tensile strength greater, higher tensile modulus, tenacity at break greater) and low density, compared to the homogeneous materials.

[005] The largest class in terms of volume commercial industrial scale, is that of composite organic matrix, wherein the matrix material is generally a polymer. The matrix of a composite polymer material is either a thermoplastic polymer or a thermosetting polymer.

[006] The thermosetting polymers consist of three-dimensional crosslinked structures. Crosslinking is obtained by cooking reactive groups in a prepolymer. Cooking can for example be obtained by heating the polymer chains to crosslink and harden the material permanently. To prepare the polymer composite material, the prepolymer is mixed with the other component, such as beads or glass fibers, or the other component is wetted or impregnated and subsequently cooked. Examples of prepolymers or thermoset polymers for the matrix material are unsaturated polyesters, vinyl esters, epoxy or phenolic materials.

[007] A major drawback of a thermosetting polymeric matrix is ​​its crosslinking. The matrix can not easily be shaped into other forms. Once the crosslinked polymer, the shape is fixed. This also makes difficult the recycling of the thermosetting composite material and or mechanical or structured manufactured items, comprising said thermosetting composite material, are burned in a cement or discarded in a landfill. Another major drawback of all thermosetting matrices is their fragility.

[008] To allow thermoforming and recycling is preferred to use thermoplastic polymers.

[009] Thermoplastic polymers consist of linear or branched polymers that are not crosslinked or highly crosslinked. The thermoplastic polymers are heated to mix the components necessary for producing the composite material and are cooled to freeze the final shape. The problem of such molten thermoplastic polymers is their very high viscosity. In order to prepare a polymer composite material based on a thermoplastic polymer, a thermoplastic polymer resin, commonly called "syrup" is used to impregnate the reinforcing material, for example a fibrous substrate. Once cured, the thermoplastic polymer syrup constitutes the matrix of the composite material. At the time of the impregnation, the viscosity of the impregnating syrup must be controlled and adapted to not be too fluid or too viscous, in order to properly impregnate each fiber of the fibrous substrate. When the wetting is only partial, as the syrup is too fluid or too viscous, it appears areas respectively "bare", that is to say not impregnated, and areas are formed on the polymer drops fibers which are at the origin of the creation of bubbles. These zones "naked" and these bubbles create the appearance of defects in the final composite material which are responsible, inter alia, loss of mechanical strength of the final composite material.

[010] Molded objects can be obtained by injection of a liquid syrup into a mold and polymerization of the liquid syrup comprising a monomer and an initiator to start or initiate polymerization. There are initiators or initiator systems which are activated by heat, that is to say, the mold is heated to start the polymerization. There are also applications where the "hardening cold" necessary or desired, an accelerator is usually added to the liquid syrup. "Curing cold" means that the polymerization takes place or can be started at ambient temperature, that is to say less than 40 ° C. The mold need not be heated but may be heated in addition to accelerate the kinetics.

[011] Once all of the compounds required for the polymerization are combined in the form of a liquid syrup: monomer, initiator and accelerator, the system is active and the polymerization inevitably start after a certain period of time. This time is generally less than 30 minutes. This means that the liquid syrup must be used almost immediately; it has a life of very limited pot.

[012] Accordingly, the compounds necessary for the polymerization, that is to say the monomer, the initiator and accelerator are mixed together as a liquid syrup which a moment just prior to injection. This is accomplished by using an injection machine 2 components, with a mixing head, immediately before the injection head. The first component may include the monomer or monomers and the accelerator while the second component includes the initiator could also be mixed with the monomer or monomers. The early start of the polymerization is avoided.

[013] In general, for the polymerization of a syrup made from methacrylic or acrylic compounds, the first component comprises a mixture of methacrylic polymer, methacrylic monomer and a tertiary amine. The second component comprising the initiator system, is generally a solid. It is used as a powder, for example benzoyl peroxide (BPO noted later). Attempts to mix benzoyl peroxide (BPO) with the monomer. Solubilizing the peroxide powder in the monomer is often incomplete, non-solubilized powder can then settle, resulting in obtaining a non-homogeneous solution. Another problem of solid initiators that are not properly solubilized lies in the fact that their accumulation in the pipes of an injection machine can cause obstruction of the supply lines of the machine, causing its blocking and immobilization for cleaning or her case.

[014] One solution may be to solubilize the initiator in a solvent such as acetone, ethanol or a phthalate, for example, but this leads to high costs and the presence of a solvent is not desirable in the methods of making such composite materials. In addition, the rate of solvent required to solubilize the initiator is generally too high and inconsistent with the ratio ((meth) acrylic acid / initiator) of machines. This is particularly the case with benzoyl peroxide (BPO) initiator for which the content should not exceed 5% by weight of the syrup.

[015] An alternative solution is to use a liquid peroxide which can initiate the polymerization of the syrup in comparable kinetics to those of the initiator systems based BPO firm. Thus, the polymerization reaction of the thermosetting resins of unsaturated polyesters, for example, may be initiated free-radically with a methyl ethyl ketone peroxide (MEKP) or hydroperxoyde (HP) liquid solution. Room temperature polymerization reaction is accelerated by incorporating a cobalt salt such as cobalt octoate or cobalt naphthenate, for example. However, this system comprising an initiator in the form of a liquid ^ peroxide and an accelerator in the form of a metal salt to cobalt-based, does not allow the polymerization of vinyl monomers thermoplastic types acrylate or methacrylate because the degradation liquid peroxide generates oxygen in the medium, which then inhibits polymerization of methacrylates. On the other hand, energy methacrylates activation is not achieved with methyl ethyl peoxydes (ECP).

[016] One solution to this problem can then consist in adding styrene in addition to (meth) acrylic but it poses environmental problems and safety premature aging ultraviolet radiation.

[017] Another solution may be to add aldehydes. Thus, document WO2003 / 008463 discloses a process for polymerizing vinyl monomers and / or oligomers comprising at least one vinyl radical. To this end, the vinyl monomer is mixed with at least one agent supplying dioxygen, at least one aldehyde and at least one accelerator.

However, the aldehyde or aldehydes are added in too large quantities, which may adversely affect the mechanical properties of the final composite part obtained from a fibrous material impregnated with syrup and polymerized. Moreover, this solution does not allow either to keep Typical dosages of initiator, which are typically less than 5% by weight of the syrup, because the aldehyde is not stable in monomer syrup, it is to be added with the initiator. Finally, these systems can be accelerated by incorporating a cobalt salt. But cobalt is a toxic substance classified so that the plaintiff seeks to avoid.

[018] There are also documents describing two-component formulations for dental applications, for example, which require curing system wet. Thus, document US 2012/0059083 discloses a two-component formulation, a first component A comprises multifunctional methacrylic monomers and oligomers, fillers and 1 cumene hydroperoxide and including a second component B comprises multifunctional methacrylic monomers and oligomers, loads, a reducing compound from the family of thiourea and a vanadium salt. However, it was verified, in particular a mixture of 1, 4-butanediol dimethacrylate and epoxy methacrylate oligomer, as syrups (meth) acrylic viscous liquid, mainly comprising methacrylic or acrylic components monofunctional, are much less reactive than mixtures of (meth) acrylic monomers and multifunctional oligomers which are known to accelerate the polymerization reaction. In addition, the viscosity of the formulation described in this document seems to be high, which may also contribute to the acceleration of the reactivity of the composition. Or, one seeks to achieve a syrup whose viscosity is not too high, to allow complete and correct impregnation of the fibers of a fibrous substrate.

[019] EP 1997862 describes a formulation comprising urethane acrylates, fillers and vanadium acetylacetonate. The urethane acrylates are known to be much more reactive compounds that mono-methacrylic functional monomers. In addition, the viscosity of the formulation described herein is between 1000 and 10000mPa · s. This formulation does not allow to obtain a fast polymerization with less viscous syrups based mono-functional monomers.

[020] The document US 4,083,890 discloses a system comprising a thermosetting resin based on unsaturated polyester (or vinyl ester), a hydroperoxide and vanadium in proportions of between 0.002 and 1% metal. The addition of a ketone peroxide delays the gel. The disclosed vanadium is vanadium neodecanoate solution in 6% metal or vanadium Nouryact Accelerator VN-2 from Akzo Nobel company (vanadium monobutyldihydrophosphite in dihydrophosphite monobutyl). All the resins are in styrene or chlorostyrene. Gold, vanadium carboxylates or vanadium monobutyldihydrophosphite do not allow to obtain rapid polymerization syrup (meth) acrylic-based monofunctional monomer. This is probably due to the reactivity of aromatic vinyl monomers and unsaturated polyester oligomers which is much greater than that of the monomers (meth) acrylic monofunctional only.

[021] WO 2014/013028 discloses a syrup (meth) acrylic polymer comprising a (meth) acrylic monomer

(Meth) acrylic acid and an initiator to start the polymerization of (meth) acrylic acid, said initiator being in the form of a liquid peroxide compound. Optionally there further comprises a tertiary amine. This document does not describe, and does not suggest more, the use of a vanadium salt in combination with the tertiary amine to accelerate the polymerization kinetics.

[022] WO 2014/174098 discloses a syrup (meth) acrylic polymer comprising a (meth) acrylic monomer

(Meth) acrylic acid and an initiator to start the polymerization of (meth) acrylic acid, said initiator being in the form of a liquid peroxide compound in a temperature range between 0 ° and 50 ° C. It also comprises at least one organic aldehyde, an organic peracid and an accelerator based on transition metal salt. He cites metals such as Mn, Co, Fe or Cu, but it does not specify, however, that the transition metal can be vanadium. This document does not describe either, the use of a tertiary amine in combination with a vanadium salt to accelerate the polymerization kinetics.

[023] The document US 3,476,723 discloses a syrup monomer of alkylmethacrylate and methylmethacrylate polymer, a benzoyl peroxide as initiator, a vanadium accelerator and an aliphatic aldehyde having 1 to 18 carbon atoms in the molecule . This document presents the vanadium based accelerator system and aldehyde as advantageous over the use of a tertiary amine used in the prior art, because once polymerized polymers obtained do not fade under the effect of rays the sun. This document does not describe, and does not suggest more, the use of a tertiary amine in combination with a vanadium salt to accelerate the polymerization kinetics.

[024] Finally, document US 3,238,274 discloses a thermosetting resin system based on an unsaturated polyester, an oxide and / or vanadium carboxylate, a mono- or dialkyl phosphate and a hydroperoxide. Vanadium rate can be very low (less than 0.02% metal). However, with thermoplastic syrups monomer based on (meth) acrylic mono-functional, these vanadium salts do not allow to obtain a fast polymerization, comparable to the gel time described herein, as the intrinsic reactivity of resins unsaturated polyester and styrene is greater than the reactivity of the monomers

(Meth) acrylic mono-functional at the base of the syrup according to one invention.

[025] The prior art does not disclose a syrup (meth) acrylic stable liquid, adapted to be polymerized at room temperature by means of a liquid initiator that can be easily used in all existing injection molding machines without obstructing their supply lines.

[026] The prior art does not describe either syrup (meth) acrylic acid that enables to obtain, after impregnating a fibrous substrate with said syrup then polymerizing said syrup, composite parts whose mechanical properties are not degraded .

[027] The prior art does not describe either from solution compatible with an industrial process for impregnating a fibrous substrate, wherein the polymerization syrup (meth) acrylic impregnation is "cold" in less than 30 minutes and preferably in less than 20 minutes.

[Technical problem]

[028] The invention therefore aims to overcome the disadvantages of the prior art by providing a syrup (meth) acrylic viscous liquid that is stable, easy to use, can be used on any injection machine RTM method or existing infusion without obstructing its supply lines, the polymerization is compatible with industrial processes of impregnating fibrous substrate and manufacturing composite parts.

[029] According to another object of the present invention the syrup (meth) acrylic viscous liquid is intended for the impregnation or injection molding and can be easily prepared in a system with one or both component (s) and mixed so homogeneous prior to injection or impregnation.

[030] Another object of the present invention is to provide a method of impregnating a fibrous substrate with such a syrup (meth) acrylic viscous liquid to wet completely, properly and homogeneously the fibrous substrate during the impregnation, so as not to degrade the mechanical performance of the composite part obtained after polymerization.

[031] Yet another object of the present invention is to manufacture a three-dimensional composite part or a mechanical part or structured composite comprising a thermoplastic material and having satisfactory mechanical properties such as high rigidity and a Young's modulus of at least 15 GPa.

[Brief description of the invention]

[032] Surprisingly, the Applicant has discovered a syrup (meth) acrylic viscous liquid comprising:

a) a (meth) acrylic acid,

b) a (meth) acrylic acid,

c) an initiator to start the polymerization of (meth) acrylic acid, said initiator being in the form of a liquid peroxide compound in a temperature range between 0 ° and 50 ° C,

said syrup being characterized in that the initiator is combined with an accelerator system comprising:

d) a vanadium salt and

e) a tertiary amine,

is homogeneous and suitable for use on existing injection molding machines without obstruction from its supply lines, has a polymerization time compatible with industrial processes of impregnating fibrous substrates and for producing composite parts, and allows impregnation complete and correct a fibrous substrate.

[033] Surprisingly, the Applicant has also found that use of this syrup (meth) acrylic acid for impregnating a fibrous substrate, said fibrous substrate being constituted by long fibers, permits obtaining an impregnation complete and correct the fibrous substrate.

[034] Likewise, the Applicant has found that a process of impregnation for impregnating a fibrous substrate, said fibrous substrate being composed of long fibers and said method being characterized in that it comprises an impregnation step said fibrous substrate with a liquid syrup

(Meth) acrylic acid comprising:

a) a (meth) acrylic acid,

b) a (meth) acrylic acid,

c) an initiator to start the polymerization of (meth) acrylic acid, said initiator being in the form of a liquid peroxide compound in a temperature range between 0 ° and 50 ° C,

the initiator is combined with an accelerator system comprising:

d) a vanadium salt and

e) a tertiary amine,

allows obtaining a correct and complete impregnation of the fibrous substrate.

[035] Surprisingly, it has further been discovered a process for polymerizing such a syrup (meth) acrylic viscous liquid, said syrup being a two-component system comprising a first component resulting from a mixture of the compounds a), b ), d), e) and a second component comprising the initiator compound c), said method comprising mixing the first and second bi-component system component less than 10 minutes prior to injection into a mold or impregnating a fibrous substrate, provides a fast curing "cold" compatible with the industrial manufacturing processes of mechanical parts and provides mechanical or structured parts having satisfactory mechanical properties.

[036] Surprisingly, it has further been discovered that a composite part manufacturing method comprising the following steps: a) impregnating a fibrous substrate with such a syrup (meth) acrylic viscous liquid,

b) polymerizing the syrup (meth) acrylic viscous liquid impregnating said fibrous substrate,

provides mechanical or structural elements having parts satisfaisanteses mechanical properties.

[Detailed description of the invention]

[037] The term "fibrous substrate" as used, refers to fabrics, felts or nonwovens which may be in the form of strips, mats, braids, strands or pieces.

[038] The term "vinyl monomer" as used, refers to all types of monomers which comprise a structure H2C = CHR.

[039] The term "(meth) acrylic" as used, refers to all types of acrylic and methacrylic monomers.

[040] The term "PMMA" as used, refers to homopolymers and copolymers of methyl methacrylate (MMA), the proportion by weight of MMA into PMMA being at least 70% by weight for the copolymer of MMA.

[041] The term "monomer" as used, refers to a molecule that can undergo polymerization.

[042] The term "monofunctional monomer" as used, refers to a molecule that can undergo polymerization and which has a single function that can undergo polymerization, preferably a single double link type C = C.

[043] The term "polymerization" as used, refers to the process of converting a monomer or a monomer mixture in a polymer.

[044] The term "thermoplastic polymer" as used, refers to a polymer which is liquid or becomes liquid more or less viscous when heated and which can take new shapes by the application of heat and pressure.

[045] The term "thermoset polymer" as used, refers to a prepolymer containing a soft, solid or viscous that transforms irreversibly into a network polymer infusible and insoluble by curing.

[046] The term "polymer composite" as used, refers to a multicomponent material comprising a plurality of different phase domains, wherein at least one type of phase domain is a continuous phase and wherein at least one component is a polymer.

[047] The term "initiator" as used, refers to a chemical species which reacts with a monomer to form an intermediate compound capable of successfully connecting a large number of other monomers in a polymer compound.

[048] The term "liquid peroxide" as used, refers to an organic peroxide inherently liquid or used as a solute in a solvent and whose dynamic viscosity is between 1 and 1000 mPa * s, preferably between 1 and 100 mPa * s at 25 ° C.

[049] The term "accelerator" as used, refers to an organo-soluble compound added to a liquid composition to accelerate the kinetics of a room temperature polymerization reaction.

[050] The term "accelerator system," as used, refers to a system comprising a plurality of organo-soluble compounds which, in combination, are capable of accelerating the kinetics of a room temperature polymerization reaction.

[051] According to a first aspect, the present invention relates to a syrup (meth) acrylic viscous liquid comprising:

a) a (meth) acrylic acid,

b) a (meth) acrylic acid,

c) an initiator to start the polymerization of (meth) acrylic acid, said initiator being in the form of a liquid peroxide compound in a temperature range between 0 ° and 50 ° C,

said syrup being characterized in that the initiator is combined with an accelerator system comprising:

d) a vanadium salt and

e) ,

f) a tertiary amine.

[052] Regarding the (meth) acrylic acid, the latter can be chosen from alkyl methacrylates or alkyl acrylates. According to a preferred embodiment, the (meth) acrylic acid is polymethyl methacrylate (PMMA). It should be therefore understood that polymethyl methacrylate (PMMA) may designate a methyl methacrylate homopolymer (MMA) or a copolymer of MMA or mixtures thereof.

[053] In particular, it may be a mixture of at least two homopolymers of MMA having a different molecular weight, or a mixture of at least two copolymers of MMA having a composition identical monomers and different molecular weight, or a mixture of at least two MMA copolymers having a composition different monomers. It can also be a mixture of at least a MMA homopolymer and at least one copolymer of MMA.

[054] According to one embodiment, the homo- or copolymer of methyl methacrylate (MMA) comprises at least 70%, preferably at least 80%, preferably at least 90% and more preferably at least 95% by weight methyl methacrylate. Methyl methacrylate copolymer (MMA) may also comprise 0.3 to 30% by weight of at least one monomer containing at least one ethylenic unsaturation and being capable of copolymerizing with methyl methacrylate. Among such monomers there may be mentioned: acrylic and methacrylic acids and (meth) acrylates in which the alkyl group contains from 1 to 12 carbon atoms. For example, there may be mentioned methyl acrylate and (meth) acrylate, butyl or 2-ethylhexyl. Preferably the comonomer is an alkyl acrylate wherein the alkyl group contains from 1 to 4 carbon atoms.

[055] According to a preferred embodiment, the methyl methacrylate copolymer (MMA) comprises from 70% to 99.7%, preferably from 80% to 99.7%, preferably 90% to 99.7% and more preferably from 90% to 99.5% by weight methyl methacrylate and 0.3% to 30%, preferably from 0.3% to 20%, preferably from 0.3% to 10% and more preferably from 0.5% to 10% by weight of at least one monomer containing at least one ethylenic unsaturation which can copolymerize with methyl methacrylate. Preferably, the comonomer is selected from methyl acrylate or ethyl acrylate or mixtures thereof.

[056] The polymer weight average molecular weight (meth) acrylic acid is generally high, and can be therefore greater than 50 000 g / mol, preferably greater than 100 000 g / mol.

The average molecular weight can be measured by steric exclusion chromatography (SEC).

[057] With respect to the, or, monomer (s) (meth) acrylic acid (s) included in the syrup (meth) acrylic acid in addition to the (meth) acrylic acid, it (they) is (are) chosen ( s) from a (meth) acrylic or vinyl monomer or mixture thereof.

[058] In contrast, the syrup comprises not more than 5 parts by weight of aromatic vinyl monomer. Such an aromatic vinyl monomer may for example be selected from alpha-methylstyrene, ortho-, beta- or para-methylstyrene, tert-butylstyrene, nitrostyrene, and mixtures thereof. Preferably, such an aromatic vinyl monomer is not styrene, and still more preferably, the syrup does not contain a vinyl aromatic monomer.

[059] In addition, the syrup comprises not more than 5 parts by weight, preferably not more than 3 parts by weight, more preferably not more than 1 part by weight of monomer

Multifunctional (meth) acrylate, that is to say comprising several functions (meth) acrylates in monomer. Even more preferably, the syrup does not include such monomers

Multifunctional (meth) acrylics.

[060] The syrup may further comprise, from the monomers (meth) acrylic-functional oligomeric (meth) acrylates, such as epoxy (meth) acrylates or urethane (meth) acrylates or polyester (meth ) acrylates. Preferably these oligomers are present in the syrup in the amount of at most 5 parts by weight, preferably at most 3 parts by weight, more preferably at most 1 part by weight and still more preferably n syrup 'not contain.

[061] Preferably, the syrup comprises predominantly of the monomer or monomers or (meth) acrylic monofunctional (s). Primarily mean that at least 95% of monomers in the syrup are monofunctional, preferably at least 97%, more preferably at least 98%, even more preferably at least 99%, preferably at least 99.5%, more preferably 99.9%, and even cheaper all the monomers are monofunctional.

[062] Preferably, the monomer or monomers (meth) acrylic acid is (are) chosen (s) from acrylic acid, methacrylic acid, alkyl acrylic monomers, methacrylic monomers alkyl, the alkyl group can be linear, branched or

cyclic and containing 1 to 22 carbon atoms, preferably 1 to 12 carbon atoms.

[063] Preferably, the at least one constituent monomer syrup (meth) acrylic acid is (are) chosen (s) from methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid, acrylate, n-butyl, isobutyl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl methacrylate, isobornyl methacrylate heptyl acrylate, n-octyl acrylate, 2-octyl acrylate, iso-octyl methacrylate, 2-ethylhexyl acrylate, butyl diglycol methacrylate, dicyclopentenyloxyethyl methacrylate, methacrylate ethoxyethyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, hydroxylpropyl, N-vinylpyrrolidone and mixtures thereof.

[064] More preferably, the (meth) acrylic acid is selected from methyl methacrylate, isobornyl acrylate or acrylic acid and mixtures thereof.

[065] According to a preferred embodiment, at least 50% by weight, preferably at least 60% by weight of monomer

(Meth) acrylic or (meth) acrylic acid is methyl methacrylate.

[066] According to one embodiment of more preferred at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight and advantageously at least 80% by weight and even more preferably 90 % by weight of (meth) acrylic acid is methyl methacrylate mixture with isobornyl acrylate and / or acrylic acid.

[067] With respect to the initiator to start the polymerization of (meth) acrylic acid, it is preferably a radical initiator.

[068] Advantageously, the free radical initiator is a liquid perxoyde in a temperature range between 0 ° C and 50 ° C.

[069] The liquid peroxide is an organic peroxide comprising 2 to 30 carbon atoms, selected from hydroperoxides, ketone perxoydes or peroxyesters.

[070] Preferably the liquid peroxide is a hydroperoxide selected from ter-butyl hydroperoxide, the monohydroperxoyde the paraméthanehydroperoxyde, tert-amylhydroperoxyde or

1 'hydroperxoyde cumene. Even more preferably, the monohydroperoxide or paraméthanehydroperoxyde 1 or cumene hydroperoxide.

[071] Such an initiator, with decomposition, generates free radicals that contribute to start the polymerization reaction.

[072] The amount of initiator is preferably from 0.1 parts by weight and 5 parts by weight, preferably between 0.1 and 3 parts by weight, and even more preferably between 0.2 and 1 part by weight in view of the amount of the monomer

(Meth) acrylic and (meth) acrylic acid, the latter two together being 100 parts by weight. The amounts are given in view of liquid syrup (meth) acrylic injected or used for the impregnation.

[073] With regard to the accelerator system, the system - it preferably comprises a combination a combination of a vanadium salt with a tertiary amine. Thus, any use of cobalt metal classified as toxic, is ruled out.

[074] The accelerator system is soluble in the syrup made from (meth) acrylic, and makes it possible to cause decomposition of the initiator to generate free radicals needed to start the polymerization. Vanadium salt is a salt comprising phosphorus ligands, such as the dialkyl phosphate or trialkyl phosphate, dialkyl phosphates preferably with alkyl chains comprising from 2 to 20 carbon atoms.

[075] Advantageously, the vanadium content (which comes vanadium salt) in the syrup is less than 1 parts by weight, more preferably it is less than 0.5 parts by weight, preferably it is less than or equal to 0.2 part by weight and even more preferably it is between 0.0005 and 0.1 parts by weight. Although the proportions of vanadium salt in the syrup are very low, the accelerator system is highly reactive, due to the combined action of the tertiary amine.

[076] To facilitate the use of the vanadium salt is diluted in solvents or plasticizers to have a viscosity suitable for use.

[077] The use of a well chosen tertiary amine, in suitable proportions, makes it possible to polymerize the syrup (meth) acrylic acid in a short time, typically less than 30 minutes and preferably less than 20 minutes, compatible with the production of composite parts using standard injection molding machines. In particular it was discovered that the same amino can both speed up or slow the polymerization reaction, depending on its level in the syrup (meth) acrylic acid.

[078] Advantageously, in order to obtain rapid polymerization kinetics, that is to say a time of polymerization less than 30 minutes and preferably less than 20 minutes, the tertiary amine content in the syrup (MEHT) acrylic should preferably be between 0.05 part by weight and 1 part by weight, preferably between 0.1 and 0.8 part by weight and more preferably between 0.2 and 0.6 parts by weight. Such proportions tertiary amine achieve satisfactory kinetics.

[079] The tertiary amine is preferably selected from N, N-dimethyl-p-toluidine (DMPT), N, N-dihydroxyethyl-p-toluidine

(DHEPT), N, -diethyl-p-toluidine (DEPT), or para-toluidine ethoxylate (PTE).

[080] All components of the syrup (initiator, accelerator system) separately are stable for several months. They are liquid and solubilize well in the (meth) acrylic acid so as to form a syrup (meth) acrylic homogeneous ..

[081] The use of both a liquid and a liquid accelerator initiator system, they solubilize well in the (meth) acrylic acid so as to form a syrup (meth) acrylic homogeneous. The initiator is easy to use, it is stable and industrialized.

[082] The initiator is liquid, it will not clog of the injection machine supply lines used for the implementation of the method of impregnating the fibrous substrate and / or mechanical parts of the manufacturing process or of structured elements or articles made of composite material according to the invention and this, even before being mixed with the monomer mixture (s)

(Meth) acrylic acid (s), polymer (s) (meth) acrylic acid (s) and the accelerator system.

[083] Similarly, the initiator being soluble in the syrup, after mixing of the initiator with the monomer mixture (s)

(Meth) acrylic acid (s), polymer (s) (meth) acrylic acid (s), and the accelerator system, the liquid syrup (meth) acrylic acid will not clog the feed lines of the injection machine used for the implementation of the impregnation method of the fibrous substrate and / or mechanical parts of the manufacturing process or structured elements or articles made of composite material according to one invention.

[084] With regard to the liquid syrup (meth) acrylic acid according to the invention to be used to impregnate a fibrous substrate, for example, said fibrous substrate being constituted by long fibers, it comprises a monomer or a monomer mixture ( meth) acrylic acid, at least one (meth) acrylic monomer dissolved in the initiator and the accelerator system. This solution is commonly called "syrup" or "prepolymer".

[085] Advantageously, the liquid monomer syrup contains no deliberately added additional solvent.

[086] The (meth) acrylic acid is completely soluble in the (meth) acrylic acid.

[087] The (meth) acrylic acid is PMMA, that is to say, the homo- or copolymer of methyl methacrylate (MMA) or a mixture thereof as defined above.

[088] The, or, monomer (s) (meth) acrylic acid (s) is (are) the (s) even (s) as that (those) set (s) above.

[089] The (meth) acrylic monomer

(Meth) acrylic syrup (meth) acrylic liquid are present in an amount of at least 40% by weight, preferably at least 50% by weight, preferably at least 60% by weight and more preferably at least 65% by weight of the syrup (meth) acrylic total liquid.

[090] The (meth) acrylic monomer

(Meth) acrylic syrup (meth) acrylic liquid are present in an amount of at most 90% by weight, preferably at most 85 wt% and more preferably at most 80% by weight of the syrup (meth) total liquid acrylic.

[091] The polymer (meth) acrylic in the liquid syrup (meth) acrylic acid represents at least 10% by weight, preferably at least 15% and more preferably at least 20% by weight of the total weight of the liquid syrup (meth ) acrylic acid.

[092] The polymer (meth) acrylic in the liquid syrup (meth) acrylic acid represents at most 60% by weight, preferably at most 50%, advantageously at most 40% and more preferably at most 35% of the weight total liquid syrup (meth) acrylic acid.

[093] Preferably, the syrup (meth) acrylic viscous liquid comprises:

a) 10 to 60 parts by weight of (meth) acrylic acid, b) 40 to 90 parts by weight of (meth) acrylic acid,

c) 0.1 to 3 parts by weight, preferably 0.1 to 1 part by weight of initiator,

d) less than 1 parts by weight, preferably less than 0.5 part by weight, more preferably less than 0.2 part by weight, and even more preferably between 0.0005 and

0.1 part by weight of vanadium, from vanadium salt and

e) 0.05 to 1 part by weight, preferably 0.1 to 0.8 parts by weight and more preferably from 0.2 to 0.6 parts by weight of tertiary amine,

f) in view of the sum of (meth) acrylic and (meth) acrylic acid, the two together being 100 parts by weight.

[094] The dynamic viscosity of the syrup (meth) acrylic liquid is within a range from 10 mPa * s to 10,000 mPa * s, preferably 10 mPa * s to 5000 mPa * s and more preferred 50 mPa * s to 5000 mPa * s and preferably 100 mPa * s to 1000 mPa * s and more preferably 100 mPa * s to 500 mPa * s. The viscosity of the syrup may be easily measured with a rheometer or viscometer. The dynamic viscosity is measured at 25 ° C. Syrup (meth) acrylic liquid has a Newtonian behavior, which means that it does not exhibit shear thinning, the dynamic viscosity being independent of shear and in a rheometer or the mobile speed in a viscometer.

[095] If the viscosity of the syrup (meth) acrylic liquid at a given temperature is too high for the impregnation process and for proper impregnation, it is possible to heat the syrup to obtain a liquid syrup in limits of the dynamic viscosity range mentioned above to the respective temperature at which the impregnation takes place for sufficient wetting and proper and complete impregnation of the fibrous substrate.

[096] The liquid syrup (meth) acrylic acid according to the invention can therefore be used on all existing machines for injection molding process resin transfer (RTM) or infusion.

[097] The liquid initiator allows polymerization of the monomer

(Meth) acrylic acid with short cycle times.

[098] The quantities of initiator and accelerator system are relatively low (less than 5 parts by weight), mechanical properties of the composite material will thereby be degraded.

[099] The syrup using no or very little vinyl aromatic monomers, it does not degrade the resistance to ultra violet radiation of the resulting composite material.

[0100] The reactivity of the liquid syrup (meth) acrylic acid according to the invention is less sensitive to temperature variations in the workshops, than the syrups of the prior art, thereby to retain comparable cycles throughout the year time .

[0101] The syrup (meth) acrylic liquid may also include other additives and fillers. A charge under the present invention is not considered an additive. All additives and all charges can be added to the syrup

(Meth) acrylic liquid prior to impregnation.

[0102] As additives there may be mentioned organic additives such as impact modifiers or block copolymers, heat stabilizers, UV stabilizers, lubricants, dispersants, antifoaming agents, rheology modifiers, waxes , modifiers membership, mold release agents, and mixtures thereof.

[0103] The impact modifier is in the form of fine particles having an elastomer core and at least one thermoplastic shell, the particle size being generally less than 1 μι and advantageously between 50 and 300 nm. The impact modifier is prepared by emulsion polymerization. The modifier content of the impact resistance of the liquid monomer syrup is from 0 to 50% by weight, preferably from 0 to 25% by weight, and preferably 0 to 20% by weight.

[0104] As fillers, there may be mentioned carbon nanotubes or inorganic fillers, including mineral nanofillers (T1O2, silica), and carbonates and hydrates. Content of the charge in the liquid monomer syrup is from 0 wt% to 60 wt%.

[0105] With regard to the fibrous substrate, there may be mentioned fabrics, felts or nonwovens which may be in the form of strips, mats, braids, strands or pieces. The fibrous material can have different shapes and sizes, one-dimensional, two-dimensional or three-dimensional. A fibrous substrate comprises an assembly of one or more fibers. When the fibers are continuous, their assembly form tissues.

[0106] The dimensional shape corresponds to the linear fibers. The fibers can be discontinuous or continuous. The fibers may be arranged randomly or in the form of a continuous filament in parallel to each other. A fiber is defined by its ratio of length, which is the ratio between the length and diameter of the fiber. The fibers used in the present invention are long fibers or continuous fibers. The fibers have an aspect ratio of at least 1000, preferably at least 1500, more preferably at least 2000, preferably at least 3000 and most preferably of at least 5 000.

[0107] The two-dimensional shape corresponds to the fibrous mats or nonwoven reinforcement or reinforcements woven or woven strands or bundles of fibers, which can also be braided. Although these two-dimensional shapes have a certain thickness and therefore in principle a third dimension, they are considered two-dimensional according to the present invention.

[0108] The three-dimensional shape corresponds for example to mats or fibrous nonwoven reinforcements or bundles of fibers or mixtures thereof, stacked or folded assembly of the two-dimensional shape in the third dimension.

[0109] The fibrous material may be of natural or synthetic origin. As a natural material, there may be mentioned vegetable fibers, wood fibers, animal fibers or mineral fibers.

[0110] Natural fibers such as sisal, jute, hemp, flax, cotton, coconut fiber and banana fibers. Animal fibers such as wool or hair.

[0111] As plastics there may be mentioned polymeric fibers selected from thermoset polymer fibers, thermoplastic polymer or mixtures thereof.

[0112] The polymer fibers may be made of polyamide (aromatic or aliphatic), polyester, polyvinyl alcohol, polyolefins, polyurethanes, polyvinyl chloride, polyethylene, unsaturated polyesters, epoxy resins and esters vinyl.

[0113] The mineral fibers may also be chosen from glass fibers, in particular of type E, R or S2, carbon fibers, boron fibers or silica fibers.

[0114] The fibrous substrate of the present invention is selected from vegetable fibers, wood fibers, animal fibers, mineral fibers, synthetic polymeric fibers, glass fibers, carbon fibers or mixtures thereof. Preferably, the fibrous substrate is selected from the inorganic fibers.

[0115] The fibers of the fibrous material have a diameter between 0, 005 and 100 μιτι μιτι, preferably between 1 and 50 μιτι μιτι, more preferably between 5 and 30 μιτι μιτι and advantageously between 10 and 25 μιτι μπι.

[0116] Preferably, the fibers of the fibrous material of the present invention are selected from continuous fibers (which means that the length ratio does not apply as for long fibers) to the one-dimensional form, or long fibers or continuous forming bi- or three-dimensional shape of the fibrous substrate.

[0117] A further aspect of the present invention is the impregnation method, for impregnation of a fibrous substrate, said fibrous substrate being composed of long fibers and said method being characterized in that it comprises a step of impregnating said fibrous substrate with a syrup

(Meth) acrylic liquid comprising

a) a (meth) acrylic acid,

b) a (meth) acrylic acid,

c) an initiator to start the polymerization of (meth) acrylic acid, said initiator being in the form of a liquid peroxide compound in a temperature range between 0 ° and 50 ° C,

the initiator is combined with an accelerator system comprising: d) a vanadium salt and

e) a tertiary amine.

[0118] Another further aspect of the present invention is a process for polymerizing the liquid viscous syrup (meth) acrylic acid according to the invention, said syrup being a bi-component comprising a first component resulting from a mixture system of the compounds a) , b), d), e) and a second component comprising the initiator compound c), said method comprising mixing the first and second component of the bi-component system less than 10 minutes prior to injection into a mold or impregnation a fibrous substrate.

[0119] Another aspect of the present invention is a parts manufacturing process or structured mechanical goods, characterized in that it comprises the following steps:

a) impregnating a fibrous substrate with the syrup (meth) acrylic viscous liquid according to the invention,

b) polymerizing said syrup (meth) acrylic liquid impregnating said fibrous substrate.

[0120] In the most advantageous manner, the parts manufacturing process or mechanical or structured articles comprising the polymer composite material is selected from transfer molding or resin infusion.

[0121] All methods include the step of impregnating the fibrous substrate with the liquid syrup (meth) acrylic acid according to the invention, before the polymerization step in a mold.

[0122] Preferably, the impregnation of the fibrous substrate in step a) is performed in a closed mold.

[0123] Advantageously, step a) and step b) are carried out in the same mold closed.

[0124] Advantageously, the polymerization temperature in step b) is less than 120 ° C, preferably below 80 ° C and more preferably below 40 ° C. The polymerization temperature and the temperature of the start of the polymerization, the peak temperature could be higher.

[0125] Using the same mold prevents the transfer of the material after impregnation.

[0126] The parts or mechanical or structural articles made contain no additional solvent added intentionally, since the syrup contained no additional solvent for the impregnation step.

[0127] With regard to the parts or structured mechanical articles made according to the present invention, they comprise at least 20% by weight of fibrous substrate, preferably at least 40% by weight of fibrous material, preferably at least 50% by weight of fibrous material and preferably at least 55% by weight of fibrous material, relative to the total composition.

[0128] The parts or structured mechanical articles made according to the present invention include at most 99% by weight of fibrous material, preferably at most 95% by weight of fibrous material, preferably at most 90% by weight of fibrous material and advantageously at most 80% by weight of fibrous material, relative to the total composition.

[0129] The parts manufacturing process or mechanical or structured articles according to the invention complete wetting, correct and homogeneous fibrous substrate during impregnation. The wetting of the fibers during impregnation has no defects, for example due to bubbles and voids which decrease the mechanical performance of parts or mechanical or structured products manufactured.

[0130] The components or mechanical or structured articles manufactured according to the invention comprise essentially no pores. "Pore" refers to a spherical void with a diameter of at least 1 μιτι or more empty or ellipsoidal elongate in the form of an oblate having a main axis the smaller of at least 0.5 μιτι or more. "Comprising substantially no pores" means that pores represent less than 1% by volume, preferably less than 0.5% by volume and more preferably less than 0.2% by volume of the total volume of the mechanical parts or articles or structural manufactured.

[0131] The transfer molding resin is a method using a mold assembly with two sides that shapes both surfaces of a composite material. The lower face is a rigid mold. The upper surface may be a rigid or flexible mold. The flexible mold can be made of composite materials, silicone or extruded polymeric films such as nylon. Two sides assemble to form a mold cavity. The distinctive characteristic of the transfer molding resin is that the fibrous substrate is placed in this cavity and the mold assembly is closed before introduction of the liquid syrup (meth) acrylic acid. Transfer molding resin comprises numerous variations which differ in the mechanical introduction of syrup (meth) acrylic liquid into the fibrous substrate in the mold cavity. These variations range from vacuum infusion molding resin transfer assisted by a vacuum (VARTM the acronym "Vaccuum Assisted Resin Transfer Molding"). This process can be carried out at ambient temperature or at elevated temperature. "Ambient temperature" means 10 ° C and 50 ° C. "Elevated temperature" means up to 200 ° C. An increased temperature is preferably between 50 ° C and 160 ° C.

[0132] In the case of the infusion process, the liquid syrup (meth) acrylic acid should have the viscosity suitable as regards the material of the polymer composite preparation process. The liquid syrup (meth) acrylate is sucked into the fibrous substrate in a special mold by applying a slight vacuum. The fibrous substrate is completely infused and impregnated with the liquid syrup (meth) acrylic acid.

[0133] An advantage of this method is the large amount of fibrous material in the composite.

[0134] Regarding the use of three-dimensional parts or mechanical or structured products manufactured according to the invention, automotive applications can be mentioned, marine applications, railway applications, sports, aviation and aerospace applications, photovoltaic applications, computer-related applications, telecommunications-related applications and wind energy applications.

[0135] In particular, the three-dimensional mechanical or structural part is an automotive part, a boat part, a gear part, a sports article, a part airplane or helicopter, a spacecraft piece or rocket, a piece of photovoltaic module, a wind turbine room, a piece of furniture, a component or building, room telephone or mobile phone, a computer room or TV room of printer and photocopier.

comparative Examples

[0136] Example 1 (Comparative) a syrup is prepared by dissolving 25 parts by weight of PMMA in 75 parts by weight of MMA which is stabilized in MEHQ (hydroquinonemonoméhtyléther). 100 parts by weight of syrup was added 0.8 part by weight of benzoyl peroxide (BPO-Luperox A75 Arkema) and 0.3 parts by weight DEPT (N, -diethyl-p-toluidine). The syrup has a dynamic viscosity of 520mPa * s at 25 ° C. BPO powder is not completely dissolved in the syrup. After stirring was stopped, the solid particles are still visible and they settle in the bottom of the container.

[0137] The syrup is polymerized in a vessel with a volume of 100 ml at room temperature or 25 ° C plus or minus 1 ° C. Temperature is measured using a temperature sensor placed in the syrup. After 40 minutes, the temperature reaches the peak.

[0138] Example 2 (comparative) is prepared the same basic syrup based on MMA and PMMA as in Example 1. To 100 parts by weight of MMA + PMMA syrup is added 1 part by weight of peroxide methylethylketone (PMEC- K12 Arkema Luperox) which is a liquid product and 0.018 part by weight of cobalt octoate

(Sigma Aldrich). The syrup was transparent.

[0139] The syrup is polymerized in a vessel with a volume of 100 ml at an ambient temperature of 25 ° C plus or minus 1 ° C. Temperature is measured using a temperature sensor placed in the syrup. The temperature reaches the peak after 24 hours.

[0140] Example 3 (Invention): preparing a syrup by dissolving 23 parts by weight of PMMA in 77 parts by weight of MMA which is stabilized in MEHQ (hydroquinonemonoméhtyléther).

100 parts by weight of MMA + PMMA syrup is added 1 part by weight of cumene hydroperoxide (CHP - CU80 Arkema Luperox) which is a liquid, 0.9 part by weight of PTE (N, - diethyl-p-toluidine -Bisomer PTE from GEO Specialty chemicals) and 0.6 part by weight of vanadium dibutyl phosphate in propylene glycol (VP0132 OMG Borcher) containing 5% by mass vanadium. The syrup was transparent.

[0141] The syrup is polymerized in a vessel with a volume of 100 ml at an ambient temperature of 25 ° C plus or minus 1 ° C. Temperature is measured using a temperature sensor placed in the syrup. The temperature reaches the peak after only 10 minutes.

[0142] Example 4 (Invention): preparing the same basic syrup based on MMA and PMMA as in Example 3. To 100 parts by weight of MMA + PMMA syrup is added 1 part by weight of cumene hydroperoxide (CHP - CU80 Arkema Luperox) which is a liquid, 0.3 part by weight of PTE (N, -diethyl-p-toluidine -Bisomer PTE from GEO Specialty chemicals) and 0 , 2 part by weight of vanadium dibutyl phosphate in propylene glycol (VP0132 OMG Borcher) containing 5% by mass vanadium. The syrup was transparent.

[0143] The syrup is polymerized in a vessel with a volume of 100 ml at an ambient temperature of 25 ° C plus or minus 1 ° C. Temperature is measured using a temperature sensor placed in the syrup. The temperature reaches the peak after 15 minutes and the polymerized matrix is ​​transparent.

[0144] Example 5 (Invention): preparing a plurality of base syrups based on MMA and PMMA as in Example 3. To 100 parts by weight of MMA + PMMA syrup is added 1 part by weight a liquid hydroperoxide, of PTE (N, -diethyl-p-toluidine -Bisomer PTE from GEO Specialty chemicals) in propotions which vary from syrup to another, and 0.2 part by weight of vanadium dibutyl phosphate propylene glycol (VP0132 OMG Borcher) containing 5% by mass vanadium. [0145] Thus, a first syrup does not include amine, a second syrup comprises from 0.1 part by weight of PTE, a third syrup comprises from 0.2 part by weight of PTE, a fourth syrup comprises 0.3 parts by weight PTE fifth syrup comprises 0.4 parts by weight of PTE, sixth syrup comprises from 0.5 part by weight of PTE, a seventh syrup comprises 0, 65 part by weight of PTE, and an eighth syrup comprises 0.8 parts by weight of PTE.

[0146] Each syrup is polymerized in a vessel with a volume of 100 ml at an ambient temperature of 25 ° C plus or minus 1 ° C. Temperature is measured using a temperature sensor placed in the syrup.

[0147] The time to reach the peak temperature characteristic of the polymerization of (meth) acrylic was recorded for each syrup and is listed in Table I below.

[0148]

Tableau I

[0149] The results obtained demonstrate that the kinetics of polymerization is very satisfactory for proportions of tertiary amine in the syrup of between 0.05 and 1 part by weight, preferably between 0.1 and 0.8 parts by weight and even more preferably between 0.2 and 0.6 parts by weight.

[0150] Example 6 (Invention): preparing a plurality of base syrups based on MMA and PMMA as in Example 3. To 100 parts by weight of MMA + PMMA syrup is added 1 part by weight a liquid hydroperoxide, 0.3 part by weight of PTE (N, N-diethyl-p-toluidine -Bisomer PTE from GEO Specialty chemicals), and vanadium dibutyl phosphate in propylene glycol (VP0132 Borcher OMG) which contain 5% by mass vanadium in proportions that vary from syrup to another.

[0151] Thus, a first syrup comprises from 0.1 part by weight of VP0132, a second syrup comprises from 0.2 part by weight of VP0132, a third syrup comprises 0.3 parts by weight of VP0132, a fourth syrup comprises 0.4 part by weight of VP0132, a fifth syrup comprises from 0.5 part by weight of VP0132, a sixth syrup comprises 0.8 parts by weight of VP0132 and seventh syrup comprising 1 part by weight of VP0132.

[0152] Each syrup is polymerized in a vessel with a volume of 100 ml at an ambient temperature of 25 ° C plus or minus 1 ° C. Temperature is measured using a temperature sensor placed in the syrup.

[0153] The time to reach the peak temperature characteristic of the polymerization of (meth) acrylic was recorded for each syrup and is listed in Table II below.

[0154]

Tableau II

[0155] The results obtained demonstrate that the kinetics of polymerization is very satisfactory for proportions of vanadium salt, containing 5% by weight of vanadium, from 0.1 to 1 part by weight, corresponding to vanadium contents between 0.005 to 0.05 part by weight.

[0156] The syrup (meth) acrylic acid according to the invention has the advantage of being stable over time, to polymerize quickly, so that it is compatible with industrial impregnation processes and manufacturing three-dimensional composite parts while comprising low amounts of accelerator and without use of multifunctional monomers or vinyl aromatic monomers, or cobalt salts as accelerators.

CLAIMS

Syrup (meth) acrylic viscous liquid, whose dynamic viscosity is within a range of 10 MPa * s at 10000mPa · s at 25 ° C comprising:

a) a (meth) acrylic acid,

b) a (meth) acrylic acid,

c) an initiator to start the polymerization of (meth) acrylic acid, said initiator being in the form of a liquid peroxide compound in a temperature range between 0 ° and 50 ° C,

said syrup being characterized in that the initiator is combined with an accelerator system comprising:

d) a vanadium salt and

e) a tertiary amine.

Syrup (meth) acrylic acid according to claim 1, characterized in that the salt of Vanadium d) is a salt comprising phosphorus ligands, such as phosphate dialkyl or trialkyl phosphate, preferably dialkyl phosphates with alkyl chains comprising between 2 and 20 carbon atoms.

Syrup (meth) acrylic acid according to claim 1, characterized in that the tertiary amine e) is selected from among N, N-dimethyl-p-toluidine (DMPT), N, N-dihydroxyethyl-p-toluidine (DHEPT ), N, N-diethyl-p-toluidine (DEPT), para-toluidine ethoxylate (PTE)

Syrup (meth) acrylic acid according to any one of claims 1 to 3, characterized in that compound c) liquid peroxide is an organic peroxide comprising 2 to 30 carbon atoms selected from hydroperoxides, ketone perxoydes or peroxyesters.

Syrup (meth) acrylic acid according to claim 4, characterized in that the peroxide compound is a hydroperoxide selected from: tert-butyl hydroperoxide, the monohydroperxoyde, the

paraméthanehydroperoxyde, tert-amylhydroperoxyde or

1 'hydroperxoyde cumene.

Syrup (meth) acrylic acid according to one of claims 1 to 5, characterized in that it comprises:

a) 10 to 60 parts by weight of (meth) acrylic acid, b) 40 to 90 parts by weight of (meth) acrylic acid, c) 0.1 to 3 parts by weight, preferably 0.1 to 1 part by weight of initiator,

d) less than 1 parts by weight, preferably less than 0.5 part by weight, more preferably less than 0.2 part by weight, and even more preferably from 0.0005 to 0.1 part by weight vanadium from vanadium salt and

e) 0.05 to 1 part by weight, preferably 0.1 to 0.8 parts by weight and more preferably from 0.2 to 0.6 parts by weight of tertiary amine,

in view of the sum of (meth) acrylic and (meth) acrylic acid, the two together being 100 parts by weight.

Syrup (meth) acrylic acid according to any one of the preceding claims, characterized in that, of the constituent monomers of the syrup, there are between 0 and 5 parts by weight of aromatic vinyl monomer and preferably there is 0.

Syrup (meth) acrylic acid according to claim 7, characterized in that the aromatic vinyl monomer is not styrene.

Syrup (meth) acrylic acid according to any one of the preceding claims, characterized in that, of the constituent monomers of the syrup, there are between 0 and 5 parts by weight of multifunctional monomer and preferably there is 0.

Syrup (meth) acrylic acid according to any one of the preceding claims, characterized in that, of the constituent monomers of the syrup, it further there is between 0 and 5 parts by weight of oligomers functionality methacrylates and preferably there 0.

Syrup (meth) acrylic acid according to any one of the preceding claims, characterized in that it has a dynamic viscosity of a value in the range of 10 MPa * s at 10000mPa · s, preferably from 50MPa to 5000mPa * s * s, preferably from 100 mPa to 1000 mPa * s * s and more preferably 100 mPa * s to 500 mPa * s.

Use of the syrup (meth) acrylic acid according to one of claims 1 to 11 for impregnating a fibrous substrate, said fibrous substrate being composed of long fibers, the fibers have an aspect ratio of at least 1000 .

Process for polymerizing a syrup (meth) acrylic viscous liquid according to any one of claims 1 to 11, said syrup being a two-component system comprising a first component resulting from a mixture of the compounds a), b), d), e) and a second component comprising the initiator compound c), said method comprising mixing the first and second component of the bi-component system less than 10 minutes prior to injection into a mold or impregnating a fibrous substrate.

Impregnation method, for impregnating a fibrous substrate, said fibrous substrate being constituted by long fibers, said method being characterized in that it comprises a step of impregnating said fibrous substrate with a syrup (meth) acrylic viscous liquid comprising:

a) a (meth) acrylic acid,

b) a (meth) acrylic acid,

c) an initiator to start the polymerization of (meth) acrylic acid, said initiator being in the form of a liquid peroxide compound in a temperature range between 0 ° and 50 ° C,

the initiator is combined with an accelerator system comprising:

d) a salt of vanadium and

e) a tertiary amine.

Impregnation method according to claim 14, characterized in that the syrup (meth) acrylic viscous liquid comprising: a) 10 to 60 parts by weight of (meth) acrylic acid, b) 40 to 90 parts by weight of (meth ) acrylic acid, c) 0.1 to 3 parts by weight, preferably 0.1 to 1 part by weight of initiator,

d) less than 1 part by weight, preferably less than 0.5 part by weight, more preferably less than 0.2 part by weight, and even more preferably from 0.0005 to 0.1 part by weight vanadium from vanadium salt and

e) 0.05 to 1 part by weight, preferably 0.1 to 0.8 parts by weight and more preferably from 0.2 to 0.6 parts by weight of tertiary amine,

in view of the sum of (meth) acrylic and (meth) acrylic acid, the two together being 100 parts by weight.

A method of manufacturing parts or mechanical structured articles, characterized in that it comprises the following steps:

a) 1 impregnating a fibrous substrate with a syrup (meth) acrylic viscous liquid according to one of claims 1 to 11,

b) polymerizing said syrup (meth) acrylic viscous liquid impregnating said fibrous substrate.

A method according to claim 16, characterized in that the impregnation of the fibrous substrate in step a) is performed in a closed mold.

A method according to any one of claims 16 to 17, characterized in that step a) for impregnating a fibrous substrate and the step b) of polymerization are carried out in a closed mold.

19. A method according to any one of claims 16 to 18, characterized in that the method is selected from transfer molding or resin infusion.

20. A method according to any one of claims 16 to 19, characterized in that the temperature of the polymerization in step b) is less than 120 ° C, preferably below 80 ° C and more preferably less than 40 ° C.

21. Three-dimensional mechanical or structural part obtained by the manufacturing method according to one of claims 16 to 20.

22. Part according to claim 21 which is an automotive part, a boat part, a gear part, a sports article, a part airplane or helicopter, a spaceship or rocket piece, a piece of photovoltaic module, a wind turbine room, a piece of furniture, a component or building, room telephone or mobile phone, a computer room or television, a printer room or photocopier.