A method for manufacturing a single-strand filament-resin composite comprising filaments embedded in a cross-linked resin using a magnolol-based resin composition

Abstract

The present invention relates to a method for manufacturing at least one single-strand filament-resin composite comprising filaments embedded in a cross-linked resin, using a magnolol-based resin composition. The present invention also relates to a composite based on at least one reinforcing element and said resin composition.

Description

Title of the invention: Method for manufacturing a single-strand filament-resin composite comprising filaments embedded in a cross-linked resin using a magnolol-based resin composition. Technical field

[0001] The present invention relates to the field of resin compositions and composites, such as filament-resin composite monostrands.

[0002] Composite reinforcements based on filament-resin composite monostrands are known to those skilled in the art. An example of such a reinforcement, described for example in patent EP 1,167,080 (or US 7,032,637), is that of glass-resin composite monostrands (“CVR” for short) which exhibit high mechanical properties. The monostrands comprise continuous, unidirectional glass fibers impregnated in a crosslinked vinyl ester resin.

[0003] Document FR 3 031 757 describes a multi-composite reinforcement based on CVR monostrands exhibiting improved mechanical properties. This document describes the use of an epoxyvinylester resin composition, also comprising a phosphine-type photoinitiator and a crosslinking agent, tris(2-hydroxyethyl)isocyanate triacrylate.

[0004] These monostrands find applications in particular in connection with the reinforcement of semi-finished products or finished articles in rubber such as tires for vehicles, of the pneumatic or non-pneumatic type.

[0005] Thanks to the above properties, it was shown in patent EP 1 167 080 that it was advantageously possible to substitute such single strands in CVR for steel cables, as new reinforcement elements for pneumatic tire belts, thus making it possible to significantly lighten the structure of the tires.

[0006] Patent application EP 1 174 250 (US equivalents 6 926 853 or US equivalent 7 484 949) has proposed a continuous manufacturing process for such CVR single strands, comprising the following essential steps:

[0007] - to create a rectilinear arrangement of glass fibers and to train this arrangement in a direction of advancement;

[0008] - in a vacuum chamber, degas the fiber arrangement by the action of the vacuum;

[0009] - upon exiting the vacuum chamber, after degassing, passing through a chamber vacuum impregnation so as to impregnate said fiber arrangement with the resin in liquid state to obtain an impregnated material containing the fibers and the resin;

[0010] - passing said impregnated material through a calibration die having a cross-section of predefined surface and shape, to impose on it a single-strand shape;

[0011] - downstream of the process, in a UV irradiation chamber, stabilize, solidify the monostrand by photopolymerization of the resin under the action of UV;

[0012] - then wind up the single strand thus obtained for storage.

[0013] However, in these composite reinforcements, the resin compositions used classically include a photocurable resin, a photoinitiator and a crosslinking agent.

[0014] The photocurable resins generally used are vinylester resins, which are solid or liquid and very viscous at room temperature, thus making their use on an industrial scale difficult. In order to reduce their viscosity, these photocurable resins are generally sold commercially with a reactive diluent, which is often styrene, at a concentration of up to approximately 50% by weight of the photocurable resin. Nevertheless, despite its presence, the viscosity of these resins remains high, such that the implementation of processes involving such resin compositions is often difficult.

[0015] At present, when styrene is perceived more and more negatively, it would be desirable to reduce the rate of reactive diluent present in photocurable resins.

[0016] Furthermore, the crosslinking agent is added to these resins in order to increase the glass transition temperature of the crosslinked resin composition. These resin compositions therefore generally have a high manufacturing cost. Description of the invention

[0017] The Applicant unexpectedly discovered that the presence of a resin comprising at least one specific monomer unit in a resin composition facilitates the implementation of single-strand manufacturing processes incorporating said resin. Furthermore, the Applicant discovered that such a resin improves the thermal properties and increases the glass transition temperature of these resin compositions, without degrading mechanical properties, such as Young's modulus.

[0018] The present invention relates to a method for manufacturing at least one single strand of filament-resin composite comprising filaments embedded in a cross-linked resin, comprising the following steps:

[0019] a) to create a straight arrangement of filaments and to drive this arrangement in a direction of advancement;

[0020]

[0021] (b) contacting said arrangement of filaments with a resin composition to obtain an impregnated material containing the filaments and the resin composition; said resin composition comprising: - at least one photocurable resin chosen from the group consisting of resins comprising at least one monomer unit of the following formula (I):

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030] in which: Ri and R2, whether identical or different, represent, independently of each other, a hydrogen atom, a group containing an acrylate function, or a group containing a methacrylate function. and provided that Ri and R2 do not both represent a hydrogen atom; and - at least one photoinitiating agent; c) pass said impregnated material through a calibration die having a predefined surface area and shape section, to impose on it a single-strand shape; d) downstream of the line, in a crosslinking chamber, polymerize the resin composition under the action of ultraviolet or visible radiation, the crosslinking chamber comprising a tube transparent to ultraviolet or visible light, called a crosslinking tube, through which the single strand being formed passes. The invention also relates to a resin composition based on at least one photocurable resin as defined above, and a composite based on at least one reinforcing element and at least one crosslinked resin composition. In this application, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass. The expression "composition based on" means a composition comprising the mixture and / or the in situ reaction product of the different constituents used, some of these constituents being able to react and / or being intended to react with each other, at least partially, during the different phases of manufacturing the composition; the composition can thus be in a totally or partially crosslinked state or in a non-crosslinked state.

[0031] By "embedded", it is meant that the reinforcing element is directly in contact with the resin composition over its entire surface, with the possible exception of the cutting areas of the composite.

[0032] By "resin composition", we mean here the resin as such or any composition based on this resin and comprising at least one additive (i.e. one or more additives) before crosslinking.

[0033] By "crosslinked" resin, it is understood that the resin is hardened (photocured and / or thermocured), in other words in the form of a network of three-dimensional bonds, in a state proper to so-called thermosetting polymers (as opposed to so-called thermoplastic polymers).

[0034] In this application, the term "fibre" is equivalent to the term "monofrain". Thus, the two terms may be used interchangeably.

[0035] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​from greater than a to less than b (i.e., excluding the bounds a and b), while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​from a to b (i.e., including the strict bounds a and b). In the present case, when an interval of values ​​is designated by the expression "from a to b", the interval represented by the expression "between a and b" is also and preferably designated. Brief description of the figures

[0036] [Fig-1] Fig. 1 represents a diagram of the single-strand synthesis process according to the invention.

[0037] [Fig. 2] Fig. 2, not drawn to scale for ease of understanding, is a drawing representing a cross-section of the single strand according to the invention. Description of the invention

[0038] As previously stated, a single strand of filament-resin composite comprising filaments embedded in a crosslinked resin is manufactured according to the process according to the invention.

[0039] Particularly advantageously, the process for manufacturing said single strand comprises the following steps:

[0040] - the speed (Vir) of passage of the single strand through the irradiation chamber is greater at 50 m / min;

[0041] - the duration (Dir) of passage of the single strand in the irradiation chamber is equal to or greater than 1.5 s and equal to or less than 10 s;

[0042] - the irradiation chamber comprises a UV-transparent tube (such as a UV-transparent tube) quartz or preferably glass), called an irradiation tube, through which the single strand in the process of formation, this tube being traversed by a current of inert gas, preferably nitrogen.

[0043] All the steps (arrangement, degassing, impregnation, calibration, polymerization, possible winding and cutting) of the process of the invention are, independently of each other, steps known to the person skilled in the art, as well as the materials (multifilament fibers) used; they have for example been described in one and / or the other of applications EP 1 074 369 Al and EP 1 174 250 Al.

[0044] Furthermore, as previously stated, the resin composition used in the manufacturing process according to the invention comprises:

[0045] - at least one photocurable resin selected from the group consisting of the resins comprising at least one monomer unit of the following formula (I):

[0046] in which:

[0047] Ri and R2, whether identical or different, represent, independently of each other, a hydrogen atom, a group containing an acrylate function, or a group containing a methacrylate function.

[0048] and provided that Ri and R2 do not both represent a hydrogen atom; and

[0049] - at least one photoinitiating agent.

[0050] Thus, the resin comprising at least one monomer unit of formula (I) is based on magnolol.

[0051] The photocurable resin as defined above is a resin capable of crosslinking in the presence of a photoinitiator under the action of light radiation, in particular ultraviolet or visible light. Preferably, the photocurable resin is a UV-curable resin.

[0052] Advantageously, the group containing an acrylate function can be an acrylate group or a glycidyl acrylate group, preferably an acrylate group.

[0053] Advantageously, the group containing a methacrylate function can be a methacrylate group or a glycidyl methacrylate group, preferably a methacrylate group.

[0054] Preferably, Ri and R2 represent an identical group.

[0055] In a particularly preferred manner, Ri and R2 both represent a methacrylate group. Thus, according to this embodiment, the photocurable resin comprises at least one magnolol-dimethacrylate unit.

[0056] Advantageously, the photocurable resin is chosen from the group consisting of resins comprising said monomer units of formula (I) in a proportion in the range of 55% to 100% by weight, preferably 80% to 100% by weight, more preferably 100% by weight relative to the total weight of the monomer units.

[0057] Thus, according to a particular embodiment, the resin comprising at least one monomer unit of formula (I) may further comprise one or more monomer units of a formula different from formula (I), in a rate less than or equal to 45% by weight in relation to the total weight of the monomer units.

[0058] Examples of such monomers may be cited, in particular acrylates, methacrylates and vinyl esters.

[0059] The photocurable resin as defined above may contain a reactive diluent, such as styrene, at a concentration of up to approximately 40% by weight of the photocurable resin. As is known to those skilled in the art, commercially available photocurable resins are often sold diluted.

[0060] The proportion of photocurable resin in the resin composition may be in the range of 82.5% to 99.5% by weight, preferably 90% to 99.5% by weight, more preferably 95% to 99% by weight, even more preferably 97.5% to 99% by weight, and better still 98% to 99% by weight, relative to the total weight of the resin composition. When the photocurable resin includes a reactive diluent, the aforementioned proportions of photocurable resin include said reactive diluent.

[0061] As is known, a photoinitiator is a molecule that creates reactive species such as free radicals, cations, or anions when exposed to ultraviolet or visible radiation. Particularly advantageously, the photocurable resin is a UV-curable resin, and the photoinitiator is a UV-reactive photoinitiator above 300 nm, preferably between 300 and 450 nm.

[0062] The photoinitiating agent is preferably chosen from the group consisting of type I photoinitiators and mixtures thereof. The photoinitiating agent may also be a photoinitiator that is not a type I photoinitiator, for example a type II photoinitiator or other, but this is not preferred.

[0063] Type I photoinitiators are chosen from the group consisting of benzoin ethers, benzyl ketals, alpha-dialkoxy-aceto-phenones, alpha-hydrody-alkyl-phenones, alpha-amino-alkyl-phenones, phosphine oxides and mixtures thereof.

[0064] Advantageously, the photoinitiating agent is chosen from the group consisting of phosphine oxides and mixtures thereof, preferably from the group consisting of mono(acyl)phosphine oxides, bis(acyl)phosphine oxides and mixtures thereof. The phosphine oxide may preferably be a bis(acyl)phosphine oxide.

[0065] By way of example of a photoinitiating agent usable within the scope of the present invention, one may mention bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (“Omnirad 819” from IGM or “speedcureBPO” from Lambson) or a mono(acyl)phosphine oxide (for example, “Esacure TPO” from IGM), such phosphine compounds being able to be used in mixture with other photoinitiators, for example, alpha-hydroxy-ketone type photoinitiators such as dimethylhydroxy-acetophenone (e.g., “Omnirad 1173” from IGM) or 1-hydroxy-cyclohexyl-phenyl-ketone (e.g., “Omnirad 184” from IGM), benzophenones such as 2,4,6-trimethylbenzophenone (e.g., “Esacure TZT” from IGM) and / or thioxanthone derivatives such as isopropylthioxanthone (e.g., "Esacure Omnirad ITX" from IGM).

[0066] The rate of photoinitiator agent is advantageously within a range of 0.5% to 2.5% by weight, preferably 0.5% to 2% by weight, more preferably 1% to 2% by weight relative to the total weight of the resin composition.

[0067] The resin composition may further comprise at least one crosslinking agent, other than a photoinitiator. The concentration of this crosslinking agent may be in the range of 0% to 15% by weight relative to the total weight of the resin composition. Advantageously, the concentration of the at least one crosslinking agent, other than a photoinitiator, is less than or equal to 4% by weight, preferably less than or equal to 2% by weight, and more preferably less than or equal to 1% by weight relative to the total weight of the resin composition.

[0068] In a particularly preferred manner, the resin composition is free of a crosslinking agent, other than a photoinitiator.

[0069] As an example of a crosslinking agent other than the photoinitiator, we can cite multifunctional acrylate or methacrylate derivatives and peroxides well known to those skilled in the art.

[0070] The crosslinking agent, other than the photoinitiator, may be chosen from the group consisting of multifunctional (meth)acrylates and their mixtures, preferably from the group consisting of tri(meth)acrylates and their mixtures. In particular, the crosslinking agent may be chosen from the group consisting of the triacrylate family.

[0071] As previously stated, the photocurable resin as defined above may contain a reactive diluent, such as styrene.

[0072] Advantageously, the resin composition is free of reactive diluent selected from the group consisting of styrene, 2-hydroxymethacrylate, methyl methacrylate, methyl acrylate, furfuryl methacrylate, and mixtures thereof, preferably free of reactive diluent.

[0073] This embodiment is particularly advantageous in the context of the current problem of seeking to reduce the use of hydrocarbons, and for example styrene, which are perceived more and more negatively.

[0074] As previously stated, the invention also relates to a resin composition based on at least:

[0075] - a photocurable resin selected from the group consisting of resins comprising at least one monomer unit of the following formula (I): (I), in which:

[0076] Ri and R2, whether identical or different, represent, independently of each other, a hydrogen atom, a group containing an acrylate function, or a group containing a methacrylate function.

[0077] and provided that Ri and R2 do not both represent a hydrogen atom; and

[0078] - a photoinitiating agent.

[0079] The various preferred embodiments described above in the context of the manufacturing process according to the invention are applicable to said resin composition according to the invention.

[0080] As previously stated, the invention also relates to a composite based on at least one reinforcing element and at least one crosslinked resin composition as defined above.

[0081] By "reinforcing element" is meant an element enabling the mechanical reinforcement of a matrix in which this reinforcing element is intended to be embedded. The reinforcing element may be a wire element.

[0082] The wire element can be metallic or textile. By "wire element", we mean an element having a length at least 10 times greater than the largest dimension of its cross-section, regardless of the shape of the latter: circular, elliptical, oblong, polygonal, in particular rectangular, square or oval.

[0083] Advantageously, the reinforcing element is a reinforcing fiber, preferably chosen from the group consisting of glass fibers, basalt, carbon, aramid, polyester, polyethylene, boron, ceramics and their combinations, preferably the reinforcing fiber is chosen from the group consisting of glass fibers.

[0084] The composite comprising a reinforcing element is preferably a single-strand filament-resin composite (hereinafter "FRC") having filaments embedded in said resin composition, said resin composition being crosslinked (i.e., a resin hardened after crosslinking). In other words, the composite comprising a reinforcing element is preferably a single-strand FRC having filaments embedded in a resin crosslinked from the resin composition as defined above.

[0085] The filaments can be chosen from the group consisting of glass, basalt, polyester filaments, and their combinations, preferably from the group consisting of glass filaments.

[0086] Thus, preferably, the monostrand is made of glass-resin composite (abbreviated “CVR”).

[0087] By way of example of fibre usable within the framework of the present invention, we may mention the glass fibre “R25H” or “SE 1200” fibrees of Owens Corning, the alkali-resistant glass fibre “AR320S-920S”, “AR640S-920S” or “AR1200S-920S” of Nippon Electric Glass or “Cem-fil” of Owens Corning, the basalt fibre “KVT400TEX14LKV41” of Basaltex, “FilvaTM” of Isomatex, the carbon fibre* HTS40” of Teijin or “ZOLTEK PX35” of Zoltek. The skilled craftsman knows very well how to adapt the sizing to the surface of the filaments to improve the compatibility of the filaments with the resin used in the mineral-resin composite, in particular with the help of a silane-type compatibilizing agent.

[0088] The filaments advantageously represent 65% to 85% by weight, preferably 70% to 80% by weight of the monostrand, and the crosslinked resin represents 15% to 35% by weight, preferably 20% to 30% by weight of the monostrand in filament-resin composite.

[0089] The weight percentage of the filaments is calculated by dividing the initial fiber count by the final monofilament count. The count (or linear density) is determined on at least three samples, each corresponding to a length of 50 m, by weighing this length; the count is given in tex (weight in grams of 1000 m of product – as a reminder, 0.111 tex is equivalent to 1 denier). The weight percentage of crosslinked resin can be obtained by calculating the difference between the final monofilament count and the initial fiber count.

[0090] Typically, the filaments are present in the form of a single multifilament fiber or several multifilament fibers linked together. In the latter case, the multifilament fibers are preferably essentially unidirectional. Each of the multifilament fibers may comprise several dozen, hundreds, or even thousands of individual glass filaments.

[0091] Advantageously, the filaments each have an average diameter ranging from 5 to 30 pm, more preferably from 10 to 20 pm.

[0092] The single strand advantageously has a diameter ranging from 0.2 to 1.3 mm, preferably from 0.25 to 1.25 mm, more preferably from 0.3 to 1.2 mm.

[0093] The average diameter covers both monofilaments of essentially cylindrical shape (with a circular cross-section) and monofilaments of different shapes, for example, oblong monofilaments (with a more or less flattened shape) or those with a rectangular cross-section. In the case of a non-circular cross-section, and unless otherwise specified, the average diameter is by convention the so-called overall diameter, that is to say, the diameter of the imaginary cylinder of revolution enclosing the monofilament, in other words, the diameter of the circumscribed circle surrounding its cross-section.

[0094] The glass transition temperature (Tg) of the crosslinked resin is preferably greater than 175°C, preferably greater than 180°C, in particular greater than 185°C. It can be measured in a known manner by DSC (Differential Scanning Calorimetry), on the second pass, for example and unless otherwise specified in this application, according to ASTM D3418 of 1999 (Mettler Toledo "822-2" DSC apparatus; nitrogen atmosphere; samples previously heated from room temperature (23°C) to 250°C (10°C / min), then rapidly cooled to 23°C, before final recording of the DSC curve from 23°C to 250°C, according to a ramp of 10°C / min). It can also be measured by TMA (thermomechanical analysis), (TMA 40 device controlled by a TC15 TA controller from Mettler Toledo).For example, cylindrical samples (e.g., 2 mm in diameter) of 10 mg can be photocured under a lamp (e.g., an Omnicure lamp) with a given wavelength (e.g., 365 nm). The sample can be placed between flat, circular Inconel discs and mounted centrally between the glass stage and the probe. The experiment can start at 25 °C, and the sample can be held for 5 min under a static load (e.g., 0.28 N), then heated, for example, to 250 °C at a heating rate of up to 10 °C / min (possibly under a nitrogen atmosphere). The sample displacement can be continuously recorded with respect to temperature. All measurements can be performed three times to ensure accuracy. The STARe evaluation software can be used to determine the glass transition temperature as the inflection point of the curve.

[0095] The composite based on at least one reinforcing element can be manufactured by any method known to a person skilled in the art, depending on the object to be produced.

[0096] The attached [Fig.1] schematically illustrates very simply an example of a device 10 enabling the production of single strands in CVR.

[0097] A reel lia is shown containing, in the illustrated example, glass fibers 11b (in the form of multifilaments). The reel is continuously unwound by drive, so as to create a straight arrangement 12 of these fibers 11b. Generally, reinforcing fibers are supplied as "rovings," that is, already in groups of fibers wound in parallel on a reel; for example, fibers marketed by Owens Corning under the designation "Advantex" fiber, with a count of 1200 tex (as a reminder, 1 tex = 1 g / 1000 m of fiber), are used. It is, for example, the tension exerted by the rotating receiver 26 that will allow the parallel fibers and the single-strand CVR to advance along the entire length of the installation 1.

[0098] This arrangement 12 then passes through a vacuum chamber 13 (connected to a vacuum pump not shown), disposed between an inlet tube 13a and an outlet tube 13b opening into an impregnation chamber 14, the two tubes preferably having rigid walls having for example a minimum cross-section greater (typically twice as much) than the total cross-section of fibers and a length much greater (typically 50 times more) than said minimum cross-section.

[0099] As already demonstrated by EP 1174250 A1, the use of rigid-walled tubing, both for the inlet orifice in the vacuum chamber and for the outlet orifice of the vacuum chamber and for the transfer from the vacuum chamber to the impregnation chamber, proves compatible with high fiber flow rates through the orifices without breaking the fibers, while also ensuring sufficient sealing. If necessary, experimentally, it is sufficient to determine the largest possible cross-sectional area, given the total cross-section of the fibers to be treated, that still provides sufficient sealing, considering the fiber feed rate and the length of the tubing. Typically, the vacuum inside chamber 13 is, for example, on the order of 0.1 bar, and the length of the vacuum chamber is approximately 1 meter.

[0100] At the outlet of the vacuum chamber 13 and the outlet tube 13b, the arrangement 12 of fibers 11b passes through an impregnation chamber 14 comprising a feed reservoir 15 (connected to a metering pump not shown) and a sealed impregnation reservoir 16 completely filled with an impregnation composition 17 based on a curable resin comprising at least one monomer unit of formula (I) as defined above. By way of example, the composition 17 further comprises (at a weight rate of 1% to 2%) a photoinitiator suitable for UV and / or UV-visible radiation with which the composition will be subsequently treated, for example bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide ("Omnirad 819" from IGM). Of course, impregnation composition 17 is in liquid form.

[0101] Preferably, the length of the impregnation chamber is several meters, for example between 2 and 10 m, in particular between 3 and 5 m.

[0102] Thus, from the impregnation chamber 14, in a sealed outlet tube 18 (still under primary vacuum), an impregnated material comprising, for example (% by weight) 65% to 75% of solid fibers 11b, the remainder (25% to 35%) being made up of the liquid impregnation matrix 17.

[0103] The impregnated material then passes through calibration means 19 comprising at least one calibration die 20 whose channel (not shown here), for example circular, rectangular, or conical in shape, is adapted to the specific manufacturing conditions. The calibration die, by means of a cross-section of determined dimensions, generally and preferably circular or rectangular, allows the proportion of resin relative to the fibers to be adjusted, while imposing on the impregnated material the shape and thickness targeted for the monofilament. By way of example, this channel has a minimum circular cross-section whose downstream orifice has a diameter slightly larger than that of the targeted monofilament. The die has a length that is typically at least 100 times greater than the minimum dimension of the cross-section.Its function is to ensure high dimensional accuracy of the finished product; it can also play a role in dosing the fiber content relative to the resin. According to one possible embodiment, the die 20 can be directly integrated into the impregnation chamber 14, which avoids, for example, the use of the outlet tube 18.

[0104] Preferably, the length of the calibration zone is several centimeters, for example between 5 and 50 cm, in particular between 5 and 20 cm.

[0105] Thanks to the calibration means (19, 20) a "liquid" composite monostrand 21 is obtained at this stage (liquid in the sense that its impregnation resin is always liquid) whose cross-section shape is preferably essentially circular.

[0106] At the output of the calibration means (19, 20), the liquid composite monostrand 21 thus obtained is then polymerized by passing through a UV irradiation chamber 22 comprising a sealed glass tube 23 through which the composite monostrand flows; said tube, the diameter of which is typically a few cm (for example 2 to 3 cm), is irradiated by a plurality (here, for example 4) of UV irradiators (24) in line ("UVAprint" lamps from the Dr. Hônle company, with a wavelength of 200 to 600 nm) arranged at a short distance (a few cm) from the glass tube.

[0107] The polymerization or UV irradiation chamber then has the function of polymerizing, cross-linking the resin under the action of UV.

[0108] The UV irradiation chamber may comprise one or more UV irradiators (or heaters). Advantageously, the irradiation chamber comprises a plurality UV, that is, at least two (two or more) UV irradiators arranged in a line around the irradiation tube. Each UV irradiator typically comprises one (at least one) UV lamp (preferably emitting in a spectrum from 200 to 600 nm) and a parabolic reflector whose focal point is the center of the irradiation tube; it delivers a linear power preferably between 2,000 and 14,000 watts per meter. More preferably, the irradiation chamber comprises at least three, and in particular at least four, UV irradiators in a line.

[0109] Even more preferably, the linear power delivered by each UV irradiator is between 2,500 and 12,000 watts per meter, in particular within a range of 3,000 to 10,000 watts per meter.

[0110] UV heaters suitable for the process are well known to those skilled in the art, for example those marketed by Dr. Hönle AG (Germany) under the reference "1055 LCP AM UK", equipped with "UVAPRINT" lamps (iron-doped high-pressure mercury lamps). The rated (maximum) power of each heater of this type is approximately 13,000 Watts, the actual power output being adjustable with a potentiometer between 30% and 100% of the rated power.

[0111] The diameter of the irradiation tube (preferably made of glass) is preferably between 10 and 80 mm, more preferably between 20 and 60 mm.

[0112] Preferably, the length of the irradiation chamber is several meters, for example between 2 and 15 m, in particular between 3 and 10 m.

[0113] In this example, the irradiation tube 23 is traversed by a nitrogen current.

[0114] The irradiation conditions are preferably adjusted so that, at the outlet of the impregnation chamber, the temperature of the CVR single strand, measured on the surface of the latter (for example using a thermocouple), is greater than the Tg of the crosslinked resin (in other words greater than 175°C), and more preferably less than 270°C.

[0115] Once the resin has polymerized (hardened), the CVR monostrand 25, now in solid state, carried in the direction of arrow F, then arrives on its final receiving reel 26.

[0116] Between the calibration die and the final receiving support, it is preferable to maintain the tensions experienced by the mineral fibers at a moderate level, preferably between 0.2 and 2.0 cN / tex, more preferably between 0.3 and 1.5 cN / tex; to control this, it will be possible, for example, to measure these tensions directly at the exit of the irradiation chamber, using appropriate tensiometers well known to those skilled in the art.

[0117] A finished composite block is finally obtained, as schematically represented in [Fig. 2], in the form of a very long continuous CVR monostrand 25, whose unit glass filaments 251 are distributed in such a way homogeneous throughout the entire volume of hardened resin 252. Its diameter is, for example, approximately 1 mm.

[0118] The continuous CVR single strand 25 can then be cut to a predetermined length (not shown in [Fig. 1]), as required, by any means known to those skilled in the art, for example, using a hydraulic guillotine, such as the "SH-5214" from Baileigh. This step can be carried out directly at the exit of the irradiation chamber 23. It can also be carried out after being conditioned onto a final receiving reel 26. In this case, it is preferable to unwind the single strand from the reel from the outermost axial end of the strand, in order to avoid helical deformation of the single strand. Indeed, if the single strand is unwound from the innermost axial end of the reel, this helical deformation of the single strand can be detrimental to the breaking strength. Examples Measurement methods

[0119] Mechanical properties

[0120] The mechanical properties in extension of the single strand in CVR (Young's modulus) were measured using an "INSTRON" 68TM50 tensile testing machine (BLUEHILL® UNIVERSAL software supplied with the tensile testing machine), according to ASTM D4848-98 (2012), at a temperature of 23°C.

[0121] The measurements were carried out on CVR monostrands with vinylester resins or with magnolol-dimethacrylate resins.

[0122] Before measurement, these monostrands were subjected to prior conditioning (storage of the monostrands for at least 24 hours in a standard atmosphere according to the European standard DIN EN 20139 (temperature of 23 °C ± 2°C; humidity of 50% ± 5%)).

[0123] The 240 mm monofilament samples were placed under tension between the jaws (distance between the jaws: 130 mm) and subjected to traction at a nominal speed of 50 m / min. All results given are an average of 10 measurements.

[0124] Thermogravimetric analysis

[0125] Thermogravimetric analyses were performed on a Mettler Toledo apparatus under a nitrogen atmosphere. The samples (10 to 15 mg) were placed in an aluminum crucible, then inserted at 25°C and heated to 900°C with a temperature ramp of 10°C / min. The temperature (Td5%) is the temperature at which a 5% weight loss of the sample is observed relative to the total weight of the sample. The maximum degradation temperature is determined by the lowest peak on the resulting thermogram.

[0126] Viscosity

[0127] Viscosity measurements were performed using the Anton-Paar ViscoQC 300 rotary viscometer at a temperature of 25°C and atmospheric pressure. The geometries used were B-SC4-18 and B-SC4-27 with a shear slope between 30% and 100%. The reference oils, which had a certificate of analysis and were recommended by Anton-Paar, were supplied by VWR. The measurements were performed according to ISO 3219 (2021).

[0128] Glass transition temperature

[0129] The glass transition temperature (Tg) of the resin compositions was measured by TMA (thermomechanical analysis) (TMA 40 apparatus controlled by a Mettler Toledo TC15 TA controller). Cylindrical samples (2 mm in diameter) of 10 mg were photocured for 5 seconds under an Omnicure lamp with a wavelength of 365 nm. The sample was placed between flat circular Inconel discs and mounted centrally between the glass stage and the probe. The experiment began at 25 °C, and the sample was held for 5 min under a static load of 0.28 N, then heated to 250 °C at a heating rate of 10 °C / min (rate under a 0.28 N load, in a nitrogen atmosphere). The displacement of the sample was continuously recorded as a function of temperature. All measurements were taken three times to ensure accuracy.The STARe evaluation software was used to determine the glass transition temperature as the inflection point of the curve. Synthesis of magnolol-dimethacrylate

[0130] Dried magnolol (250 g, 919.9 mmol) commercially available from BLDPharm was placed in a 1.5 L sulfation flask equipped with a condenser, a bubbler, a thermometer, and a nitrogen inlet. 94% methacrylic anhydride (347 g, 2.116 mmol) was added all at once, followed by butylhydroxytoluene (BHT) (0.74 g, 2000 ppm of the expected product). The resulting mixture was stirred at room temperature under nitrogen for 10 minutes. Dimethylaminopyridine (11.24 g, 10 mol% of magnolol) was then added. The reaction mixture was stirred at room temperature for 5 minutes, thoroughly purging the entire system with nitrogen, before being heated to 68°C for 16 hours. The reaction mixture was allowed to cool to room temperature before being transferred to a 3 L Erlenmeyer flask. Approximately 200 mL of dichloromethane (DCM) was used to thoroughly rinse all the apparatus.Saturated NaHCO3 was added under stirring using an addition funnel and in a thin stream to avoid a strong release of CO2 with foaming. At the end of the addition, the mixture... The mixture was shaken for 30 minutes at room temperature before being transferred to a separatory funnel. A microemulsion may occur, and to facilitate the separation of the two phases, it may be helpful to add 100 to 200 mL of saturated NaCl and DCM. The separated organic phase was washed with 2 xlL of NaHCO3, 3 xlL of HCl at pH 3, and finally 3 xlL of water. The organic phase was dried over sodium sulfate, then filtered, and the solvent was evaporated using a rotary evaporator. A viscous yellow liquid was obtained and purified by silica gel chromatography using a solvent mixture of heptane and ethyl acetate. The yield is > 80% by mass.

[0131] Magnolol (98%) is from BLD Pharmatech GmbH. Methacrylic anhydride (94%), 4-(dimethylamino)pyridine (99%), butylhydroxytolene, sodium sulfate, IM hydrochloric acid, and sodium chloride are from Sigma-Aldrich. Anhydrous dichloromethane (99.8%, maximum 0.001% water) is from Macherey-Nagel, and sodium bicarbonate is from Fisher Chemical. Deionized water (< 30 ps / cm at 24°C) is from the laboratory. Preparation of resin compositions

[0132] Three resin compositions were prepared (Cl to C3).

[0133] For each of the compositions, the photoinitiator (“Omnirad 819” from IGM) was used. The photoinitiator content was 1.5% by weight relative to the total weight of the resin composition.

[0134] When a vinyl ester resin was present, the vinyl ester resin (“ATLAC E-NOVA FW2045” from AOC) was used. When a magnolol-dimethacrylate resin was present, the magnolol-dimethacrylate resin, manufactured from magnolol-dimethacrylate synthesized according to the protocol described above, was used.

[0135] The vinyl ester resin includes styrene as a reactive diluent whereas the magnolol-dimethacrylate resin does not include a reactive diluent.

[0136] When a crosslinking agent was present (triacrylate hardener (“SR 368” from Sartomer)), the rate was 15% by weight relative to the total weight of the resin composition.

[0137] The compositions Cl, C2 and C3 are summarized in Table 1 below:

[0138] [Table 1] Compositions C1 (control) C2 (comparative) C3 (invention) Vinylester resin (% by weight) 98.5 83.5 - Magnolol-dimethacrylate resin (% by weight) - - 98.5 Photoinitiator (% by weight) 1.5 1.5 1.5 Triacrylate hardener (% by weight) - 15 - Preparation of single strands in CVR

[0139] CVR single strands were manufactured according to the process described above with a flow velocity Vir of the single strand through the irradiation chamber of 110 m / min, an irradiation time Dir of the single strand in the irradiation chamber of 2.2 s, and a length of 4 m in the irradiation chamber (single strands M1, M2, and M3). The single strands M1, M2, and M3 comprise resin compositions C1, C2, and C3, respectively.

[0140] The glass filaments of the monostrands M1 to M3 were “R25H” filaments from Owens Corning. Their diameter was 0.54 mm, the tex of the glass fibers was 300 g / km and the mass ratio of the glass fibers to the crosslinked resin was 70 / 30.

[0141] The mechanical and thermal properties of the M1 to M3 single strands, and the glass transition temperature of the Cl to C3 resin compositions are shown in Table 2 below. The Young's modulus is expressed in (GPa).

[0142] [Tables2] Monostrands M1 (control) M2 (comparative) M3 (invention) Young's modulus (GPa) 32.1 31.9 32.7 Degradation temperature Td5% (°C) 373 383 447 Maximum degradation temperature (°C) 410 415 464 Viscosity (rnPa.s) 485 776 162 Temperature Tg (°C) 170 190 232

[0143] The results presented above show that the presence of a resin comprising at least one monomer unit of formula (I) improves the glass transition temperature of the resin composition. Indeed, the glass transition temperature of composition C3 present in the single strand M3 according to the invention is higher not only than that of composition C2 present in the comparative single strand M2 but also than that of composition Cl present in the control single strand M1.

[0144] The results presented above also show that the presence of a resin comprising at least one monomer unit of formula (I) makes it possible to obtain advantageous mechanical and thermal properties.

[0145] Indeed, the Young's modulus of the M3 single strand is similar to, or even improved upon, that of the M2 single strand, but also to that of the M1 single strand. In other words, there is no significant degradation of this mechanical property, despite the absence of a crosslinking agent.

[0146] Furthermore, thermogravimetric analyses reveal a significant improvement in the degradation temperatures (Td5% and maximum degradation temperature) of composition C3 according to the invention compared to the comparative composition C2 and the control composition Cl. Thermal stability is thus improved.

[0147] The fact that the M3 single strand has similar, or even improved, mechanical properties to those of the M2 and M1 single strands represents an extremely attractive advantage, linked to the final industrial cost.

[0148] Another extremely interesting advantage is related to the absence of reactive diluent in the C3 composition present within the M3 monostrand, unlike the C2 and Cl compositions, from an environmental point of view.

[0149] Finally, thanks to the presence of the resin comprising at least one monomer unit of formula (I), exhibiting a lower viscosity, the implementation of the manufacturing process of a single strand is easier.

Claims

Demands

1. A method for manufacturing at least one single-strand filament-resin composite comprising filaments embedded in a crosslinked resin, comprising the following steps: a) making a straight arrangement of filaments and driving this arrangement in a direction of advancement; b) contacting said arrangement of filaments with a resin composition to obtain an impregnated material containing the filaments and the resin composition; said resin composition comprising: - at least one photocurable resin selected from the group consisting of resins comprising at least one monomer unit of the following formula (I): (I), in which: Ri and R2, identical or different, represent, independently of each other, a hydrogen atom, a group containing an acrylate function or a group containing a methacrylate function, and provided that Ri and R2 do not both represent a hydrogen atom;and - at least one photoinitiating agent; c) passing said impregnated material through a calibration die having a predefined surface area and shape, to impose upon it a single-strand shape; d) downstream of the die, in a crosslinking chamber, polymerizing the resin composition under the action of ultraviolet or visible radiation, the crosslinking chamber comprising a tube transparent to ultraviolet or visible light, called a crosslinking tube, through which the single strand being formed passes.

2. The method according to claim 1, characterized in that Ri and R2 represent an identical group.

3. A method according to claim 1 or 2, characterized in that Ri and R2 both represent a methacrylate group.

4. A method according to any one of the preceding claims, characterized in that the photocurable resin is selected from the group consisting of resins comprising said monomer units of formula (I) in a proportion in the range of 55% to 100% by weight, preferably 80% to 100% by weight, more preferably 100% by weight relative to the total weight of the monomer units.

5. A method according to any one of the preceding claims, characterized in that the percentage of photocurable resin in the resin composition is in the range of 82.5% to 99.5% by weight, preferably 90% to 99.5% by weight, more preferably 95% to 99% by weight relative to the total weight of the resin composition.

6. A method according to any one of the preceding claims, characterized in that the photoinitiator is chosen from the group consisting of phosphine oxides and mixtures thereof, preferably from the group consisting of mono(acyl)phosphine oxides, bis(acyl)phosphine oxides and mixtures thereof.

7. A method according to any one of the preceding claims, characterized in that the photoinitiator content is in the range of 0.5% to 2.5% by weight, preferably 0.5% to 2% by weight, more preferably 1% to 2% by weight relative to the total weight of the resin composition.

8. A method according to any one of the preceding claims, characterized in that the resin composition is free of a crosslinking agent, other than a photoinitiator.

9. A process according to any one of the preceding claims, characterized in that the resin composition is free of reactive diluent selected from the group consisting of styrene, 2-hydroxymethacrylate, methyl methacrylate, methyl acrylate, furfuryl methacrylate, and mixtures thereof, preferably free of reactive diluent.

10. Resin composition based on at least: - a photocurable resin selected from the group consisting of resins comprising at least one monomer unit of the following formula (I): (I), VX Mm ■ ■ ■ # \ in which: Ri and R2, identical or different, represent, independently of each other, a hydrogen atom, a group containing an acrylate function or a group containing a methacrylate function, and provided that Ri and R2 do not both represent a hydrogen atom; and - a photoinitiator agent.

11. Composite based on at least one reinforcing element and at least one crosslinked resin composition as defined in any one of the preceding claims.

12. Composite according to claim 11, characterized in that the reinforcing element is a reinforcing fiber, preferably chosen from the group consisting of glass fibers, basalt, carbon, aramid, polyester, polyethylene, boron, ceramics and their combinations, preferably the reinforcing fiber is chosen from the group consisting of glass fibers.

13. Composite according to claim 11 or 12, characterized in that it is a single strand of filament-resin composite comprising filaments embedded in said crosslinked resin composition.

14. Composite according to claim 13, characterized in that the filaments represent 65% to 85% by weight, preferably 70% to 80% by weight of the monostrand, and the crosslinked resin represents 15% to 35% by weight, preferably 20% to 30% by weight of the monostrand.

15. Composite according to claim 13 or 14, characterized in that the filaments each have an average diameter ranging from 5 to 30 pm, more preferably from 10 to 20 pm.

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