FR2841252A1 - Production of objects, especially panels, sheets or films, from thermosetting resins comprises using techniques normally reserved for thermoplastics - Google Patents

Abstract

Production of objects from thermosetting resins comprises using techniques normally reserved for thermoplastics.

Description

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STRUCTURING A REACTIVE LIQUID USING AN AGENT
STRENGTHENING
The present invention relates to the field of thermoset resins, particularly to a formulation based on thermosetting compounds having a thermoplastic behavior and which can be both used by the usual techniques for transforming thermoplastic materials and having the ability to react for to form a thermoset material. The invention also relates to the process for obtaining this formulation and the finished objects prepared therefrom.

 A thermoset material is defined as being formed of polymer chains of variable length interconnected by covalent bonds so as to form a three-dimensional network. The thermoset materials may be obtained for example by reaction of a thermosetting resin such as an epoxy with an amine hardener. The thermoset materials have many interesting properties that make them used as structural adhesives or as a matrix for composite materials or in applications for protecting electronic components.

 The epoxy materials have a high crosslinking density, which gives them a high glass transition temperature, Tg, which gives the material excellent thermomechanical properties. The higher the crosslinking density, the higher the Tg of the material and therefore the better the thermomechanical properties and the higher the temperature limit of use of the material. Nevertheless their implementation remains very delicate because they are liquids before reaction, which does not allow their manipulation.

 The use and implementation of epoxy resin poses handling problems. The resins that are most often fluid can not be stored easily and their liquid form imposes a

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 limited number of implementation paths. The use of solvent or the mixture of solid and liquid resins because of their molar mass is sometimes necessary to be able to reach the level of fluidity necessary for the application.

 The applicant has just found that specific formulations based on thermosetting materials and rheology regulating agents can be transformed or implemented by the usual techniques for implementing thermoplastic materials. The finished objects thus prepared have the appearance and thermomechanical properties of the thermoset materials.

 The formulations of the invention comprise a thermosetting resin and a block copolymer having at least one block consisting predominantly of methyl methacrylate units, used as a rheology control agent. These materials can be made by dissolving the copolymer in the thermosetting resin followed by the addition of the hardener and the hot crosslinking. The invention allows the manufacture of complex object based thermoset materials without the use of solvent.

 The first object of the invention is a method for preparing materials and thermoset objects based on the techniques for implementing thermoplastic materials. This process can be described by the following steps: a- preparation of a formulation based on thermosetting materials, by conventional techniques such as extrusion, calendering, mixing or dissolution in a reactor b- recovery and possible storage of the formulation prepared in a c- Preparation of finished objects by the transformation of the product obtained in b according to processing techniques usually reserved for thermoplastic materials that the skilled person knows well.

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 The formulation of the invention comprises: from 1 to 80% by weight of the total weight of the formulation of a rheology regulating agent (I) comprising at least one block copolymer chosen from SBM, BM and MBM block copolymers in which:> each block is connected to the other by means of a covalent bond or an intermediate molecule connected to one of the blocks by a covalent bond and to the other block by another covalent bond,> M is a PMMA homopolymer or a copolymer comprising at least 50% by weight of methyl methacrylate,> B is incompatible with the thermosetting resin and with the block M and its glass transition temperature Tg is less than the temperature of use of the thermoset material S is incompatible with the thermosetting resin, the block B and the block M and its Tg or its melting temperature Tf is greater than the Tg of B, from 20 to 99% by weight of the total weight of the formulation of at least one th resin ermodurable (II) - from 0 to 50% by weight of the total weight of the formulation of at least one thermoplastic material (III).

 The formulation may contain, without departing from the scope of the invention, the various organic and inorganic fillers known to those skilled in the art, such as fibers, pigments, fillers, UV absorbers, fillers which make it possible to improve fire resistance.

 The formulation of the invention has a thermoplastic behavior and can be implemented by the usual techniques for transforming thermoplastic materials but having the ability to react to form a thermoset material. This formulation can during the reaction be in a perfectly liquid or rubbery state.

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 As regards the thermoset material, it is defined as being formed of polymer chains of variable length interconnected by covalent bonds so as to form a three-dimensional network.

 By way of example, mention may be made of cyanoacrylates, bismaleimides and epoxy resins crosslinked by a hardener or crosslinked by anionic or cationic polymerization.

 Among the cyanoacrylates that may be mentioned are 2-cyanoacrylic ester which are thermoset materials obtained by polymerization of the CH 2 = C (CN) COOR monomer with different possible R groups (without the need to add a hardener).

 Thermoset formulations of the bismaleimide type are, for example: methylenedianiline + benzophenone dianhydride + nadic imide methylenedianiline + benzophenone dianhydride + pentylacetylene methylenedianiline + maleic anhydride + maleimide.

 The thermoset material is advantageously derived from the reaction of a thermosetting epoxy resin and a hardener. It is also defined as any product of the reaction of an oligomer carrying oxirane functions and a hardener. By the reactions involved in the reaction of these epoxy resins leads to a crosslinked material corresponding to a three-dimensional network more or less dense according to the basic characteristics of the resins and hardeners employed.

 By epoxy resin, hereinafter denoted by E, is meant any organic compound having at least two functions of oxirane type, polymerizable by ring opening. The term "epoxy resins" refers to all customary epoxy resins that are liquid at room temperature (23 ° C.) or at a higher temperature. These epoxy resins can be monomeric or polymeric on the one hand, aliphatic, cycloaliphatic, heterocyclic or aromatic on the other hand. By way of examples of such epoxy resins, mention may be made of diglycidyl ether of resorcinol, diglycidyl ether of bisphenol A, triglycidyl p-amino phenol, diglycidyl ether of bromo-bisphenol F, triglycidyl ether of

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 amino phenol, tetraglycidyl methylene dianiline, triglycidyl ether of (trihydroxyphenyl) methane, polyglycidyl ethers of phenolformaldehyde novolac, polyglycidyls ethers of orthocresol novolac and tetraglycidyl ethers of tetraphenyl ethane. Mixtures of at least two of these resins may also be used.

 Epoxy resins having at least 1.5 oxirane functions per molecule and more particularly epoxy resins containing between 2 and 4 oxirane functions per molecule are preferred. Epoxy resins having at least one aromatic ring, such as diglycidyl ethers of bisphenol A, are also preferred.

 With regard to the hardener in general, epoxy resins which react at room temperature or at temperatures above room temperature are used as hardeners. By way of nonlimiting examples, mention may be made of: # acid anhydrides, among which succinic anhydride, # aromatic or aliphatic polyamines, of which diamino diphenyl sulphone (DDS) or methylene dianiline or else 4 , 4'-Methylenebis- (3-chloro-2,6-diethylaniline) (MCDEA), # dicyandiamide and its derivatives.

# Imidazoles # Polycarboxylic acids # Polyphenols
With regard to the SBM block copolymer M is composed of methyl methacrylate monomers or contains at least 50% by weight of methyl methacrylate, preferably at least 75% by weight of methyl methacrylate. The other monomers constituting the M block may be acrylic monomers or not, be reactive or not. By reactive monomer is meant: a chemical group capable of reacting with the oxirane functions of the epoxy molecules or with the chemical groups of the hardener. By way of non-limiting examples of reactive functions, mention may be made of: oxirane functions, functions

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 amines, carboxy functions. The reactive monomer may be (meth) acrylic acid or any other hydrolysable monomer leading to these acids. Among the other monomers that can constitute the M block, mention may be made, by way of non-limiting example, of glycidyl methacrylate and tert-butyl methacrylate. Advantageously M consists of syndiotactic PMMA at least 60%.

 Advantageously, the Tg of B is less than 0 C and preferably less than -40 C.

 The monomer used to synthesize the elastomeric B block may be a diene chosen from butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and 2-phenyl-1,3-butadiene. . B is advantageously chosen from poly (dienes), especially poly (butadiene), poly (isoprene) and their random copolymers, or else from partially or completely hydrogenated poly (dienes). Of the polybutadienes, those with the lowest Tg are advantageously used, for example 1,4-polybutadiene of Tg (about -90 ° C.) less than that of 1,2-polybutadiene. (towards 0 C). Blocks B can also be hydrogenated. This hydrogenation is carried out according to the usual techniques.

 The monomer used to synthesize the elastomeric B block may also be an alkyl (meth) acrylate, the following Tg's are obtained in parentheses according to the acrylate name: ethyl acrylate (-24 C), butyl acrylate (-54 ° C), 2-ethylhexyl acrylate (-85 ° C), hydroxyethyl acrylate (-15 ° C) and 2-ethylhexyl methacrylate (-10 ° C). Butyl acrylate is advantageously used. The acrylates are different from those of the M block to meet the requirement of incompatible B and M.

 Preferably, the blocks B consist predominantly of polybutadiene-1,4.

 The Tg or Tf of S is advantageously greater than 23 ° C. and preferably greater than 50 ° C. By way of example of S blocks, mention may be made of those derived from vinylaromatic compounds such as styrene, amethylstyrene, vinyltoluene and those which derived from alkyl esters of

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 acrylic and / or methacrylic acids having from 1 to 18 carbon atoms in the alkyl chain. In the latter case the acrylates are different from those of the block M to meet the condition of S and M incompatible.

 The triblock S-B-M has a number-average molar mass which may be between 10,000 g / mol and 500,000 g / mol, preferably between 20000 and 200000 g / mol. The S-B-M triblock advantageously has the following composition expressed in mass fraction, the total being 100%: M: between 10 and 80% and preferably between 15 and 70%.

B: between 2 and 80% and preferably between 5 and 70%.

S: between 10 and 88% and preferably between 15 and 85%.

 The block copolymers used in the materials of the present invention may be manufactured by anionic polymerization, for example according to the methods described in patent applications EP 524,054 and EP 749,987.

 Advantageously, the proportion of impact modifier is from 10 to 60% for respectively 90 to 40% of thermoset resin.

 As regards the diblock S-B, the blocks S and B are incompatible and they consist of the same monomers and possibly comonomers as the S blocks and the B blocks of the S-B-M triblock. The blocks S and B may be identical or different from the other blocks S and B present in the other block copolymers of the impact modifier in the thermoset material.

 The diblock S-B has a number-average molar mass which may be between 10,000 g / mol and 500,000 g / mol, preferably between 20000 and 200000 g / mol. Diblock S-B advantageously consists of a mass fraction in B of between 5 and 95% and preferably between 5 and 60%.

 According to a preferred form of the invention the rheology regulating agent comprises at least one S-B-M block copolymer and at least one

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 S-B block copolymer. It advantageously comprises between 5 and 80% of S-B diblock for respectively from 95 to 20% of S-B-M triblock.

 In addition, the advantage of these compositions is that it is not necessary to purify the S-B-M at the end of its synthesis. Indeed S-BM are generally prepared from S-B and the reaction often leads to a mixture of S-B and S-B-M which is then separated to have S-B-M.

 According to an advantageous form, part of the S-B-M can be replaced by an S-B diblock. This portion may be up to 70% by weight of S-B-M.

 It would not be departing from the scope of the invention to replace all or part of the S-B-M triblock with a M-S-B-S-M or M-B-S-B-M pentablock. They can be prepared by anionic polymerization, such as the di or triblocks mentioned above, but using a difunctional initiator. The average molar mass in number of these pentablocks is in the same intervals as that of the S-B-M triblocks. The proportion of the two blocks M together, of the two blocks B or S together is in the same intervals as the proportions of S, B and M in the S-B-M triblock.

 The formulations of the invention may be prepared by mixing the thermoset resin not yet crosslinked using a conventional mixing device. It will be possible to use all the thermoplastic techniques making it possible to produce a homogeneous mixture between the thermosetting resin and the regulating agent such as extrusion, calendering, injection or pressing. The resulting product can be in the form of granules, foil or film. The material thus obtained unreacted or partially reacted may thus be in the form of a manipulable rubber material.

This implementation will be at a temperature where the reaction kinetics of the thermosetting material is slow. In step [c], during the implementation in the form of a finite object and by simply increasing the temperature, the thermosetting resin will be transformed into thermoset material. When increasing

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 temperature the rubber material during the reaction may according to the nature of the resin (II) and the agent (I) used to iron in the liquid state or remain in the rubbery state.

 It is obvious that this invention can be applied to a reactive liquid resin which can form after reaction a linear or connected polymer exhibiting a thermoplastic behavior. This step can, for example, be applied to the acrylic resin without departing from the scope of the invention.

 The finished objects of the invention can be used in various industries. By way of nonlimiting example, mention may be made, for example, of the use in the industry of high pressure and high temperature tubes which can be produced by extrusion of DGEBA-MDEA mixture with 50% of SBM at 150 ° C. and then shaped at the same time. desired temperature and crosslinked by increasing the temperature without exceeding the temperature permitting liquefaction of the formulation.

 The use of this resin may also be in the form of films of less than 100 m thick or sheet having been prepared by extrusion sheath, cast extrusion or calendering. This extrusion will be done at a temperature that makes it possible to avoid an excessive advance of the reaction, then these films or sheets can be glued to a substrate and finally crosslinked by increasing the temperature or simply stored at a temperature where the kinetics of reaction is slow for example 0 C.

 The experimental part described below illustrates the invention without limiting its scope.

Cooking conditions:
These are the usual conditions.

 It would not be outside the scope of the invention to add in the formulation the usual additives, such as thermoplastics such as polyethersulfones, polysulfones, polyetherimides, polyphenylene ethers

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Epoxy resin: it is a diglycidic ether of Bisphenol A (DGEBA) of molar mass 383 g / mol with an average number of hydroxyl group for an epoxy group of n = 0. 075, marketed by the company Ciba Geigy under the commercial reference LY556.

 Hardener: it is an amine hardener which is an aromatic diamine, 4,4'-methylenebis- (3-chloro-2,6-diethylaniline) marketed by Lonza under the trade name LONZACURE M-DEA. This product is characterized by a melting point of between 87 ° C. and 90 ° C. and a molar mass of 310 g / mol.

 SBM1: it is a triblock copolymer SBM in which S is polystyrene, B is polybutadiene and M PMMA containing 22% by mass fraction of polystyrene, 9% by mass fraction of polybutadiene and 69% by weight of polymethacrylate of methyl, obtained by anionic polymerization successively of a polystyrene block with a number-average molar mass of 7000 g / mol, a polybutadiene block with a mass of 11000 g / mol and a block of polymethyl methacrylate with an average molecular weight of 84000 g / mol. This product was prepared according to the procedure described in EP 524-054 and in EP 749 987. This product has three glass transitions, one of -90 C, the other of 95 C and the third of 130 C.

 SBM2: it is a triblock copolymer SBM in which S is polystyrene, B is polybutadiene and M PMMA containing 12% by mass fraction of polystyrene, 18% by mass fraction of polybutadiene and 70% by weight of polymethacrylate of methyl, obtained by anionic polymerization successively of a polystyrene block having a mean molar mass of 14000 g / mol, a polybutadiene block having a mass of 22000 g / mol and a block of polymethyl methacrylate having an average molecular weight of 85000 g / mol. This product was prepared according to the procedure described in EP 524-054 and in

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 EP 749. 987. This product has three glass transitions, one of -90 C, the other of 95 C and the third of 130 C.

Realization of mixtures containing other type of regulating agent such as Core-Shell or SBS.

The bark particles are dispersed in the DGEBA using a calender. The cycles are 10 minutes of mixing followed by 10 minutes of rest. The mixture is then heated to 100 ° C. (above the melting temperature of the amine) and the diamine is dispersed for 10 minutes.
The mixtures are cooked for 2 hours at 220 ° C.

Measurement of the glass transition temperature, Tg by thermomechanical analysis:
The measurement of Tg was performed by dynamic mechanical analysis on the post-fired samples using a Rheometrics Solid Analyzer RSAII apparatus. The parallelepipedal shaped samples (1 * 2.5 * 34mm3) are subjected to a temperature sweep between 50 and 250 C at a pulling frequency of 1 Hz. The glass transition temperature is taken at a maximum of tan d.

Deflation measurement:
A parallelepiped-shaped sample of size 20x20x1 mm is placed in a 100 ml beaker filled with toluene for a period of 15 days. The beaker is kept tightly closed at room temperature. After 15 days of immersion the sample is taken and its mass controlled. The percentage of swelling is obtained by the following equation:% swelling = (m15days-minital) / minital

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 The sample is then dried and weighed again to check that none of the constituents of the material have been solubilized by toluene.

Example 1 (according to the invention)
40 g of SBM of composition 203050 and of number-average molar mass of PS 7000 gr / mole block and 60 g of DGEBA DER332® epoxy mixture from DOW chemicals of molar mass 348.5 g are introduced onto a roller mixer. / mole and amine MDEA from the company Lonza. The DGEBA and the MDEA are introduced into the stoichiometric mixture of 41.53 g of DGEBA and 18.47 g of MDEA. The mixture is produced at 150 ° C. This mixture is first pressed in the form of a transparent plate 1 mm thick, its elongation at break in tension is 650% and its glass transition temperature is 0 C. This The mixture is then baked at 220 ° C. for 2 hours. this mixture has a liquefaction temperature of 150 ° C. The glass transition temperature of the obtained plate is 154 ° C. and no swelling in toluene is observable.

Example 2 (According to the invention)
40 gr of SBM of composition 203050 and of number-average molar mass of PS block 25000 gr / mol and 60 gr of DGEBA DER332® epoxy mixture from DOW chemicals of molar mass 348.5 gr are introduced onto a roll mixer. / mole and amine MDEA. The DGEBA and the MDEA are introduced into the stoichiometric mixture of 41.53 g of DGEBA and 18.47 g of MDEA.

 The mixture is produced at 150 ° C. This mixture is first pressed in the form of a transparent plate 1 mm thick, its elongation at break in tension is 700% and its glass transition temperature is 0 ° C. The mixture is then baked at 220 ° C. for 2 hours. this mixture has a liquefaction temperature of

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 C. The glass transition temperature of the resulting plate is 155 ° C and no swelling in toluene is observable.

Example 3 (according to the invention)
30 g of SBM with a composition 203050 and a number-average molar mass of the block PS 7000 g / mol, 10 g of PPO® Blendex 803 from the company Générale Electrique and 60 g of epoxy mixture DGEBA DER332 are introduced onto a roller mixer. DOW chemicals company of molar mass 348.5 gr / mole and amine MDEA. The DGEBA and the MDEA are introduced into the stoichiometric mixture of 41.53 g of DGEBA and 18.47 g of MDEA. The mixture is produced at 150 ° C. This mixture is first pressed in the form of a transparent plate 1 mm thick, its elongation at break in tension is 620% and its glass transition temperature is 0 ° C. The mixture is then baked at 220 ° C. for 2 hours. this mixture has a liquefaction temperature of 230 ° C. The glass transition temperature of the plate obtained is 158 ° C. and no swelling in toluene is observable.

Example 4 (comparative)
40 gr of SBS block copolymer and 60 gr DGEBA DER332® epoxy mixture from Dow Chemicals with a molecular weight of 348.5 gr / mol and amine MDEA are introduced onto a roller mixer. The DGEBA and the MDEA are introduced into the stoichiometric mixture of 41.53 g of DGEBA and 18.47 g of MDEA. The mixture obtained during cooling is opaque, macrosepaired and has no cohesion.

Example 5 (comparative)
On a roller mixer are introduced 40 gr of KM355 paraloid type shell core, this bark particle has a core consisting mainly of butyl acrylate and a bark

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 polymethyl methacrylate and 60 gr DGEBA DER332 @ epoxy mixture of the company DOW chemicals of molar mass 348.5 gr / mole and amine MDEA. The DGEBA and the MDEA are introduced into the stoichiometric mixture of 41.53 g of DGEBA and 18.47 g of MDEA. The mixture obtained during cooling is translucent and has no cohesion.

Claims (35)

 1. Process for preparing thermoset resin-based articles according to the following steps: a-Preparation of a formulation based on thermosetting materials b-recovery and possible storage of the formulation prepared in a- Preparation of finished objects by the transformation of the product obtained in b according to transformation techniques usually reserved for thermoplastic materials.  2. Method according to claim 1 characterized in that prepared by extrusion, calendering or dissolution in a reactor comprising: - from 1 to 80% by weight of the total weight of the formulation of a rheology regulator (I) comprising at least one block copolymer chosen from SBM, BM and MBM block copolymers in which:> each block is connected to the other by means of a covalent bond or an intermediate molecule connected to one of the blocks by a covalent bond and to the other block by another covalent bond,> M is a PMMA homopolymer or a copolymer comprising at least 50% by weight of methyl methacrylate,> B is incompatible with the thermosetting resin and with the block M and its glass transition temperature Tg is lower than the temperature of use of the thermoset material, S is incompatible with the thermosetting resin, the block B and the block M and its Tg or its melting temperature Tf is greater than the Tg of B, - from 20 to 99% by weight of the total weight of the formulation of at least a thermosetting material (II) <Desc / Clms Page number 16>  from 0 to 50% by weight of the total weight of the formulation of at least one thermoplastic material (III), the formulation may also contain organic and inorganic fillers such as fibers, pigments, UV absorbers and / or the charges for improving the fire resistance.  3. Method according to claim 2 characterized in that during step (a) the thermosetting material (II) is mixed with the agent (I) under conditions of implementation or reaction kinetics of (II) is slow, then in a second step where by increasing the temperature or any other means is allowed to initiate the reaction.  4. Process according to claim 2 or 3, characterized in that the blocks M of the block copolymers consist of at least 60% syndiotactic PMMA.  5. Process according to one of Claims 2 to 4, characterized in that the blocks M of the block copolymers comprise reactive monomers, advantageously glycidyl methacrylate, tert-butyl methacrylate or acrylic acid.  6. Process according to one of claims 2 to 5 characterized in that the Tg blocks B of the block copolymers is less than 0 C, and preferably less than -40 C.  7. Process according to one of Claims 2 to 6, characterized in that the blocks B of the block copolymers consist for the most part of polybutadiene-1,4.  8. Process according to one of claims 2 to 7 characterized in that the dienes of the block B are hydrogenated. <Desc / Clms Page number 17>  9. Process according to one of claims 2 to 6 characterized in that the block B consists of poly (butyl acrylate).  10. Process according to one of claims 2 to 9 characterized in that the Tg or Tf of S is greater than 23 C and preferably greater than 50 C.  11. Process according to one of Claims 2 to 10, characterized in that S is polystyrene.  12. Process according to one of claims 2 to 11characterized in that the number-average molar mass of the block copolymers can be between 10000 g / mol and 500000 g / mol.  13. Process according to one of Claims 2 to 12, characterized in that the number-average molar mass of the block copolymers can be between 20000 g / mol and 200000 g / mol.  14. A method according to one of claims 2 to 13 characterized in that the proportion of the agent (1) is 1 to 35% for respectively 99 to 65% of (II) and preferably 8 to 32% for respectively 92 to 68% of (II).  15. Process according to one of Claims 2 to 14, characterized in that the regulating agent (I) comprises at least one of the block copolymers MBM, SBM and at least one polymer chosen from among the bark (A), functionalized elastomers, SB block copolymers and ATBN or CTBN reactive rubbers. <Desc / Clms Page number 18>  16. A method according to one of claims 2 to 15 characterized in that the blocks S and B of the diblock S-B are those of claims 7 to 11.  17. The method of claim 16 characterized in that the diblock S-B has a number average molar mass which can be between 10000 g / mol and 500000 g / mol.  18. Process according to one of Claims 2 to 17, characterized in that the impact modifier comprises at least one SB-M block copolymer and at least one S-B block copolymer.  19. Process according to one of Claims 2 to 18, characterized in that the impact modifier comprises at least one S-BM block copolymer and at least one shell-and-bark polymer (A).  20. A method according to one of claims 2 to 19 characterized in that the impact modifier comprises at least one S-BM block copolymer, at least one reactive rubber ATBN or CTBN and optionally an S-B block copolymer.  21. A method according to one of claims 2 to 20 characterized in that all or part of the triblock S-B-M is replaced by a pentabloc MS-B-S-M or M-B-S-B-M.  22. A method according to one of claims 2 to 21 characterized in that the thermosetting resin is a thermosetting epoxy resin and a hardener.  23. Method according to one of the preceding claims characterized in that the product obtained in b is in the form of granules <Desc / Clms Page number 19> 24. The method of claim 23 characterized in that the granules are stored without time limitation.  25. A method according to one of claims 1 to 22 characterized in that the product obtained in b is in the form of sheet.  26. A process according to one of claims 1 to 22 characterized in that the product obtained in b is in the form of film.  27. The method of claim 27 or 28 characterized in that the sheet or film is stored without time limitation at a temperature below 0 c.  28. A method according to one of the preceding claims characterized in that the finished object according to c is a tube.  29. Use of the tube of claim 28 for high pressure or high temperature applications.  30. A method according to one of claims 1 to 27 characterized in that the finished object according to c is a plate.  31. Use of the plate of claim 30 as a material that can be thermoformed and used in the automotive industry.  32. A method according to one of claims 1 to 27 characterized in that the finished object according to c is a sheet.  33. Use of the sheet of claim 32 as a material for electrical and electronic applications. <Desc / Clms Page number 20>  34. Process according to one of claims 1 to 27 characterized in that the finished object according to c is a film.  35. Use of the film of claim 34 as a material for coating applications.