Block copolymers

Translation of description of equivalent WO 03095513 A2

COPOLYMERS

The present invention relates to block copolymers (block copolymers) and more specifically to thermoplastic elastomeric copolymers sequences.

Thermoplastic elastomers are known. These polymers exhibit advantageous mechanical properties (elastomers), associated with handling and forming properties attraction and ssantes (thermoplastics). While conventional elastomers usually require a chemical crosslinking step, usually non-reversible, before or after being formed or applied to a support, thermoplastic elastomers are crosslinked according to a physical phenomenon which is reversible by heating. This property allows for elastomeric compounds without chemical crosslinking step that can be difficult to achieve on certain media, or require complex training (two-component formulations or multicomponent, or formulations comprising an active catalyst only under specific conditions such as drought ). Thermoplastic elastomers may be formed (by extrusion, injection molding ...) or applied to a support in a molten form. They are used for various purposes, including plastic soft touch for consumer goods and automobile interiors, structural or mechanical items, adhesives. They can also be used as additives in thermoplastic or in compositions used in the building industry to modify the mechanical properties of said thermoplastic or compositions.

Triblock copolymers comprising two rigid lateral blocks of styrene and a flexible central block comprising units derived from diene monomers are known and used for many years. For example, there may be mentioned block copolymers of styrene / butadiene / styrene (SBS), block copolymers of styrene / (ethylene-butadiene) / styrene (SEBS) and hydrogenated. The styrene blocks are rigid blocks forming a hard phase dispersed in a soft phase of the central block (microphase separation). Without being bound to any particular theory, and simplifying, it is believed that the dispersion of the hard phase provides cohesion between the polymer chains and the other phase having elastomeric properties. This can be called cross-linking according to a physical phenomenon. Therefore, it is believed that the microphase separation of the blocks is a key factor. When heated, the rigid bottom phase and the copolymers may be handled in liquid form. An explanation of the microphase separation of block copolymers are given in Frank S. Bates and Glenn H. Fredrickson, Physics Today, published in February 1999; 32-38 pages.

Triblock copolymers mentioned above have certain drawbacks. First, the central block sometimes yellowing with age. Second, for some uses, for example as adhesives or uses where the compatibilization with other compounds is needed, other functions must be added as anhydride, carboxylic acid, ester, epoxide by copolymerizing the additional comonomers . To prevent yellowing and to satisfy certain requirements for certain uses derivatives blocks of acrylic acid esters or methacrylic acid may be a solution. In addition, the aforementioned triblock copolymers are usually prepared by an anionic polymerization process optionally a hydrogenation step. Anionic polymerization methods are usually considered to be expensive compared with polymerization processes of free radicals. Therefore, there is a need for block copolymers which can be prepared by free radical polymerization and allow phase separation of the blocks as explained above or more simply, which exhibit elastomeric properties. On the other hand, to obtain polymers of block copolymers having a high and controlled molecular weight is easier with a anionic polymerization process with a polymerization process free radicals: it may be difficult to obtain block copolymers with weight high with a controlled molecular structure and molecular weight controlled by a polymerization process free radicals. Currently, no solution was found to the problem of the proposal of a block copolymer comprising a flexible block derived primarily acrylic acid esters or methacrylic acid, at moderate costs. Else, it is known that the higher the molecular weight of the blocks, the higher the phase separation is easy. The Applicant has found new block copolymers that solve some of the aforementioned requirements or problems. These block copolymers comprise a soft block comprising acrylic acid esters or methacrylic acid which avoids delayed yellowing and leads to block copolymers having adhesion and compatibilizing properties of interest. The copolymer sequences discovered by the Applicant may be prepared by a polymerization process free radicals. Hence, the invention also relates to a block copolymer manufacturing process.

A block copolymer (block copolymer), a diblock copolymer (block A) - (block B), a tri-block copolymer (block A) - (block B) - (block A), or triblock (block A) - (block B) - (block C)

- Block A being a stiff block, comprising at least 55% of recurring units derived from a stiff monomer selected from the group consisting of styrene, acrylate, isobornyl methacrylate, isobornyl - block B is a block flexible comprising at least 55% of recurring units derived from a soft monomer selected from the group consisting of acrylic acid esters, methacrylic acid esters, and mixtures of these esters,

- The block C being a stiff block, comprising recurring units derived from a stiff monomer selected from the group consisting of styrene, isobornyl acrylate and isobornyl methacrylate, wherein:

- Block A comprises at least 6% by weight of units derived from a block A segregation monomer selected from the group consisting of acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, 2- vinylpyridine and 4-vinylpyridine or

- Block B comprises at least 6% by weight of units derived from a block B segregation monomer selected from the group consisting of acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile and vinyl pyrrolidones and

- The block copolymer has a molecular weight of more than 10 000 g / mol.

The block copolymers according to the invention may be in a solid or dried form. They may be dissolved in an organic solvent. They can be in the form of a latex dispersion in an aqueous medium. These solutions or dispersions are usually intended to be applied on a surface, and then dried, for manufacturing a film or a coating. In a dried form, the block copolymer of the invention has elastomeric properties. It also exhibits thermoplastic properties.

According to a second aspect, the invention relates to a method of manufacturing the above-mentioned block copolymer, said process is a polymerization process free radical living sequenced (and controlled), preferably involving the use of a transfer agent comprising a group of formulas - SC (S) -X-, -SC (S) -S-, or -SP (O) -X- or -SP (S) -S- where X is a sulfur atom other.

According to a third aspect, the invention relates to the use of the block copolymer defined above as the adhesive, its use in an adhesive composition and adhesive or adhesive products comprising the compositions. The block copolymer comprises at least two different blocks: Block A and Block B. It is selected from the group consisting of diblock (block A) - (block B), tri-block copolymers (block A) - (block B) - (block A) or triblock (block A) - (block B) - (block C). The block copolymer is a linear block copolymer. By linear it is meant that the blocks arrangement is linear. However, a block may include units comprising a macromolecular group side chain.

A block is usually defined by the repeating units it comprises. A block can be defined by naming a polymer or by naming monomers it is derived. In the present description, a "unit derived from a monomer" is understood to be a pattern that can be directly obtained from the said monomer by polymerizing. Thus, a "unit derived from an ester of acrylic acid or methacrylic acid" does not encompass a unit of formula -CH-CH (COOH) - or -CH-C (CH₃) (COOH) - is obtained for example by polymerizing an ester of acrylic acid or methacrylic acid followed by hydrolyzation. But a "unit derived from acrylic acid or methacrylic acid" encompasses for example a unit obtained by polymerizing a monomer and reaction to obtain units of formula -CH-CH (COOH) - or -CH-C ( CH₃) (COOH) -. At least one of the blocks, block A or the block B is a copolymer comprising at least two different repeating units derived from at least two different monomers. Block A, Block B and Block C are distinct polymers derived from different monomers, but may include some common recurring motifs. Preferably, block A and block B comprise no more than 50% of a common repeating unit (derived from the same monomer). Block C and Block B preferably do not comprise more than 50% of a common repeating unit (derived from the same monomer). Block A and Block C may include up to 94 wt% of a common repeating unit. It should be noted further that in the tri-block copolymers (block A) - (block B) -

(Block A), the two blocks may have an identical or different molecular weight. They may include units derived from the same or different block A segregation monomer. They can include the same or a different amount (at least 6 wt%) units derived said segregation monomer. The C block is a block that does not include units derived from a block of segregation monomer A or which does not include more than 6% by weight of units derived from a block of segregation monomer A.

Block A and Block C are called rigid blocks. The B block is called flexible block. In this specification, the words "rigid" and "flexible" means the property that would block without the other block (s) which is the property of a polymer composed of the same repeating units than said block preferably having the same molecular weight. A rigid polymer or block usually has a glass transition temperature of over 50 ° C and preferably above 100 ° C. A flexible polymer or block usually has a glass transition temperature below 20 ° C, more preferably below 0 ° C.

In the present description, the term "hard monomer" refers to monomers of which the polymer derivative is rigid. In the present description, the term "soft monomers" refers to monomers of which the polymer derivative is flexible. In the present specification, the molecular weight of a block copolymer refers to the weight average molecular weight of the block copolymer. The molecular weight of the polymer weighted average can be measured by chromatography gel permeation (GPC). In the present specification, the molecular weight of a block refers to the molecular weight calculated from the amounts of monomers, polymers (e.g. other block), initiators and / or transfer agents used to make the block. The skilled person knows how to calculate these molecular weights. The weight ratios between the blocks indicate the relationship between the amounts of compounds used to make said blocks, considering an extensive polymerization.

Typically, the molecular weight M of a block is calculated using the following formula:

not.

M

_ '• "c ptrrééecuurrseur

wherein M; is the molecular weight of a monomer i, ni is the number of moles of a monomer i and n_Prečur_sor is the number of moles of a compound to which the macromolecular chain of the block will be linked. Said compound may be a transfer agent or a transfer group or a previous block. If it is a previous block, the number of moles may be considered as the number of moles of a compound to which the macromolecular chain of said previous block has been linked, for example a transfer agent or a transfer group. It can also be obtained by calculation from a measured value of the molecular weight of said previous block. If two blocks are simultaneously grown from a previous block, at both ends, the molecular weight calculated according to the above formula should be divided by two. In a first embodiment:

- Block A comprises at least 55% by weight of units derived detailed rigid monomers below, - block A comprises at least 6%, preferably at least 10%, even more preferably at least 15% by weight of units derivatives detailed block A segregation monomers below,

- Block B comprises at least 55% by weight of units derived from soft monomers detailed below, - Block B includes no unit derived detailed block B segregation monomers or below does not include more than 6% of units derived any detailed block B segregation monomers below.

In a second embodiment - block A comprises at least 55 wt% of units derived from rigid monomers detailed below,

- Block A comprises no unit derived detailed block A segregation monomers or below does not include more than 6% of units derived any detailed block A segregation monomers below. - Block B comprises at least 55% by weight of units derived from soft monomers detailed below,

- Block B comprises at least 6%, preferably at least 10%, even more preferably at least 15% by weight of units derived detailed block B segregation monomers below. In a third embodiment:

- Block A comprises at least 55% by weight of units derived from rigid monomers detailed below,

- Block A comprises at least 6%, preferably at least 10%, even more preferably at least 15% by weight of units derived detailed block A segregation monomer below,

- Block B comprises at least 55% by weight of units derived from soft monomers detailed below,

- Block B comprises at least 6%, preferably at least 10%, even more preferably at least 15% by weight of units derived detailed block B segregation monomers below.

- The block B segregation monomers are different from block segregation monomers A.

The block copolymers according to the three previous embodiments may also include a C block, comprising units derived monomers rigid detailed below. Block C includes no unit derived detailed block A segregation monomers or below does not include more than 6% of any units derived from block A segregation monomers detailed below. Preferably, the block C comprises at least 80% by weight, preferably at least 94% by weight of units derived from rigid monomers.

Block A and Block B may include some different patterns of rigid units derived monomers and monomers segregation (segregation block of monomers A or block B) detailed below. If this is not the case, the amount by weight of units derived from rigid monomers, respectively flexible, is equal to 100% minus the amount of the block A segregation monomer, respectively block B.

The aforementioned rigid monomers are selected from the group consisting of styrene, isobornyl acrylate and isobornyl methacrylate.

The above block A segregation monomer are selected from the group consisting of acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, 2-vinylpyridine and 4-vinylpyridine.

The aforementioned soft monomers are selected from the group consisting of esters of acrylic acid and methacrylic acid esters, such as 2-ethylhexyl acrylate, methacrylate, 2-ethylhexyl acrylate, ethyl acrylate, methacrylate, ethyl, butyl acrylate and butyl methacrylate. Mixtures of these monomers may be used to obtain a block comprising units derived thereof, the block being thus a random copolymer. Use mixtures to control the glass transition temperature of the soft block. For example, acrylate mixtures hexyl or hexyl methacrylate and butyl acrylate or butyl methacrylate may be used. These monomers and their derivatives units or block polymer comprising said units are usually considered hydrophobic. The above block B segregation monomers are selected from the group consisting of acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile and vinyl pyrrolidones.

Without being bound to a particular theory, it is believed that the monomers referred to as segregation monomers reinforce the incompatibility of a block with another and thus allow a segregation phase, a hard phase is dispersed is a soft continuous phase. The block A segregation monomers strengthen the incompatibility of the block A to the block B. The monomers segregation of block B would strengthen the incompatibility of block B relative to the block A. Some monomers might as well reinforce the incompatibility of the block A to the block B as the incompatibility of block B relative to the block A. So some monomers are considered segregation block of monomers A and / or block segregation monomers B. However, it is preferred that both blocks A and B comprise more than 6% by weight of monomers of segregation, the segregation block monomer A is different from the block of the segregation of monomer B or the amount (% by weight) of the block segregation monomers in block A is different from the amount (% by weight) of the block B segregation monomers in the block B.

The block copolymer of the invention has a molecular weight of at least 10 000 g / mol, preferably of at least 25 000 g / mol and even more preferably at least 50 000 g / mol. The molecular weight is usually less than 200 000 g / mol. It may be less than 150 000 g / mol and even less than 100 000 g / mol. Obtain the properties of a thermoplastic elastomer having a hard phase dispersed in an elastomeric continuous phase, these low molecular weight is one of the benefits and advantages of the invention.

Preferably, block A has a molecular weight between 1000 and 30 000 and more preferably between 3 000 and 15 000 g / mol. Preferably the B block has a molecular weight between 6000 and 12 000 and more preferentially between 6000 and 97000 g / mol. More preferably, the B block has a molecular weight between 20 000 and 80 000 g / mol.

The ratio between the molecular weight of the A blocks and the molecular weight of the block B is preferably between 0.45 and 0.5, more preferably between 0.05 and 0.3.

Preferably, the block A is primarily styrene and the B block is mainly of ethyl acrylate or butyl acrylate, such as:

- Block A comprises from 75% to 90% by weight of units derived from styrene and from 10% to 25% by weight of units derived from acrylic acid or methacrylic acid and - Block B comprises at least 75% by weight of units derived from ethyl acrylate, butyl acrylate or mixtures thereof.

In a first preferred embodiment, the block copolymer is a diblock (block A) - (block B) where the block A comprises units derived from styrene and units derived from methacrylic acid and block B comprises units derived from ethyl acrylate and where:

- Block A comprises from 75% to 90% by weight of units derived from styrene and from 10% to 25% o by weight of units derived from methacrylic acid and

- Block B comprises at least 75% by weight of units derived from ethyl acrylate or ethyl acrylate and butyl acrylate.

According to a second preferred embodiment, the block copolymer is a triblock copolymer (block A) - (block B) - (block A) wherein block A comprises units deriving from styrene and units derived from methacrylic acid and block B comprises units deriving from ethyl acrylate and wherein: - block A comprises from 75% to 90% by weight of units derived from styrene and from 10% to 25%> by weight of units derived from the methacrylic acid and

- Block B comprises at least 75% by weight of units derived from ethyl acrylate or ethyl acrylate and butyl acrylate.

According to a third preferred embodiment, the block copolymer is a triblock copolymer (block A) - (block B) - (block A), wherein block A comprises units derived from styrene and units derived from methacrylic acid and block B comprises units derived from butyl acrylate and where:

- Block A comprises from 75% to 90% by weight of units derived from styrene and from 10% to 25% o by weight of units derived from acrylic acid or methacrylic acid and

- Block B comprises at least 75% by weight of units derived from butyl acrylate.

According to a fourth preferred embodiment, the block copolymer is a triblock copolymer (block A) - (block B) - (block A) wherein block A comprises units deriving from styrene and units derived from methacrylic acid and block B comprises units derived from 2-ethylhexyl acrylate, and where: - Block A comprises from 75% to 90% by weight of units derived from styrene and from 10% to 25% by weight of units derived from methacrylic acid and

- Block B comprises at least 75% by weight of units derived from acrylate, 2-ethylhexyl acrylate or a mixture of 2-ethylhexyl acrylate and ethyl acrylate and / or butyl acrylate.

According to a fifth preferred embodiment, the block copolymer is a triblock copolymer (block A) - (block B) - (block C) where the block A comprises units deriving from styrene and units derived from methacrylic acid, block B comprises units derived from acrylate, 2-ethylhexyl, butyl acrylate or ethyl acrylate and block C comprises units derived from styrene and wherein:

- Block A comprises from 75% to 90% by weight of units derived from styrene and from 10% to 25%) by weight of units derived from methacrylic acid and

- Block B comprises at least 75% by weight of units derived from acrylate, 2-ethylhexyl, butyl acrylate and / or ethyl acrylate or mixtures thereof and

- Block C comprises at least 94% by weight of styrene units.

The block copolymers according to the invention can be obtained by different methods. Exemplary methods include polymerization processes free radicals "living" or "controlled". These methods involve the use of a specific transfer agent for this purpose.

In general, the block copolymers may be obtained by any polymerization method "living" or "controlled", for example:

- The free radical polymerization controlled by xanthates according to the teaching of application WO 98/58974 and US Patent No. 6,153,705 - the free radical polymerization controlled by dithioesters according to the teaching of application WO 98/01478 ,

- The free radical polymerization controlled by dithioesters according to the teaching of application WO 99/35178,

- The free radical polymerization controlled by dithiocarbamates according to the teaching of application WO 99/35177,

- The free radical polymerization using nitroxide precursors according to the teaching of application WO 99/03894, - The free radical polymerization controlled by dithiocarbamates according to the teaching of application WO 99/31144,

- The free radical polymerization controlled by dithiocarbazates according to the teaching of application WO 02/26836, - the free radical polymerization controlled by halogenated xanthates according to the teaching of application WO 00/75207 and US application 09 / 980 387,

- The free radical polymerization controlled by dithiophosphoroesters according to the teaching of application WO 02/10223,

- The free radical polymerization controlled by a transfer agent in the presence of a compound disulphur teaching of application WO 02/22688,

- Radical polymerization controlled atom transfer (ATRP) according to the teaching of application WO 96/30421,

- Radical polymerization controlled by iniferters according Otu Education et al., Makromol. Chem. Rapid. Common, 3, 127 (1982). - Radical polymerization controlled by degenerative transfer of iodine according to the teaching of Tatemoto et al, Jpn.. 50, 127, 991 (1975), Daikin Kogyo Co Ltd Japan and Matyjaszewski et al., Macromolecules, 28, 2093 (1995)

- The group transfer polymerization according to the teaching of Webster OW, "Group Transfer Polymerization", p. 580-588, in "Encyclopedia of Polymer Science and Engineering", Vol. 7, edited by HF Mark, NM Bikales, CG Overberger and G. Menges, Wiley Interscience, New York, 1987

- Radical polymerization controlled by tetraphenylethane derivatives (D. Braun et al, Macromol Symp, 111, 63 (1996)...)

- Radical polymerization controlled by organocobalt complexes (Wayland et al, J. Am Chem Soc, 116, 7973 (1994)...).

The preferred processes are polymerization processes of living free radical block involving the use of a transfer agent. Preferred transfer agents are agents comprising a group of formula -SC (S) -Y-, -S-C (S) -S or -SP (O) -Y or -SP (S) -S- where Y is an atom of sulfur as an oxygen atom, a nitrogen atom and a carbon atom. They include dithioester groups, thioétherthione groups, dithiocarbamate groups, dithiophosphoroesters, dithiocarbazates and xanthate groups. Examples of groups contained in preferred transfer agents include groups of formulas -S-C (S) -NR-NR '₂-SC (S) NR-N = CR '₂-SC (S) -OR, -S- C (S) -X in which R and R 'are identical or different hydrogen atoms or organic groups such as hydrocarbyl groups, optionally substituted, optionally comprising heteroatoms, and X is a halogen atom. A preferred polymerization process is a living radical polymerization using xanthates.

A polymerization process free radicals "living" or "controlled" used to make the block copolymers comprises for example the steps of: a) reacting monomers or a mixture of monomers, at least one source of compound free radical and a transfer agent to obtain a first block (preferably a block a), the transfer agent being linked to said first block, b) reacting the first block, the monomers and a monomer mixture and optionally at least one compound of radical source to obtain a diblock copolymer (preferably (block a) - (block B)), c) optionally, reacting the diblock copolymer, the monomers or a monomer mixture and optionally at least a radical source compound to obtain a triblock copolymer (preferably (block a) - (block B) - (block a) or (block a) - (block B) - (block C)), and d) optionally reacting the transfer agent with means to render it inactive or eliminate.

During step a), a first block of the block copolymer polymer is prepared, preferably the block A, preferably using rigid monomers and optionally block the segregation of A. monomers during step b) , a second block is obtained, preferably a B block, connected to the first block to obtain a diblock copolymer, preferably the block B, using soft monomers and optionally block B segregation monomers during the optional step c ), a third block is obtained, connected to the second block, preferably a block a or block C to obtain a triblock copolymer, the use of rigid monomers and optionally of monomers segregation of Block A. In step d), reacting the transfer agent to render it inactive, or to avoid odor or yellowing.

Examples of transfer agents are transfer agents of the following formula (I):

\\ C - SR¹ (I)

/

R

in which :

- R is R O-, R^ZR 'N- or R^J-, R and R '^z which are identical or different, representing (i) an alkyl, acyl, aryl, alkene or alkyne or (ii) a saturated or unsaturated carbon ring, optionally aromatic, or (iii) a saturated or unsaturated heterocycle, these groups and rings ( i), (ii) and (iii) to be substituted, R³ representing H, Cl, an alkyl, aryl, alkene or alkyne, a (hetero) saturated or unsaturated ring, optionally substituted alkylthio, alkoxycarbonyl, aryloxycarbonyl, carboxy, acyloxy, carbamoyl, cyano, dialkylphosphonato or diarylphosphonato or group dialkylphosphinato or diarylphosphinato or a polymer chain,

- R¹ represents (i) an alkyl, acyl, aryl, alkene or alkyne optionally substituted or (ii) a carbonaceous ring which is saturated or unsaturated and which is optionally substituted or aromatic or (iii) a saturated or unsaturated heterocycle, possibly substituted, or a polymer chain, and the groups R¹, R², R '² and R³ may be substituted by substituted phenyl or alkyl groups, substituted aromatic groups or the following groups: oxo, alkoxycarbonyl or aryloxycarbonyl (-COOR), carboxyl (-COOH), acyloxy (- O₂CR), carbamoyl (-CONR₂), Cyano (-CN), alkylcarbonyl, alkylarylcarbonyl, arylcarbonyl, arylalkylcarbonyl, isocyanato, phthalimido, maleimido, succinimido, amidino, guanidino, hydroxyl (-OH), amino (-NR₂), Halogen, allyl, epoxy, alkoxy (-OR), S-alkyl, S-aryl or silyl, groups exhibiting a hydrophilic or ionic nature such as alkali salts of carboxylic acids or alkaline salts of acid sulfonic acid, chains of poly (alkylene oxide) (PEO, PPO), or cationic substituents (quaternary ammonium salts), R representing an alkyl or aryl group.

Preferably, the transfer agent of formula (I) is a dithiocarbonate chosen from the compounds of following formulas (IA), (IB) and (IC):

S

\\

C - S - R¹ (IA)

/ GOLD²

R =^{Ï "}. (.- 0 - C - O - R¹)_P (IB)

S II

R - O - C - O - R% (CI) S ​​II

in which :

September 9

- R and R 'represent (i) an alkyl, acyl, aryl, alkene or alkyne or (ii) a carbonaceous ring, saturated or unsaturated, optionally aromatic, or (iii) a saturated or unsaturated heterocycle, groups and rings (i ), (ii) and (iii) to be substituted,

- R¹ and R¹'Represent (i) an alkyl, acyl, aryl, alkene or alkyne or (ii) a carbonaceous ring which is saturated or unsaturated and which is optionally substituted or aromatic or (iii) a saturated or unsaturated heterocycle, optionally substituted or chain polymer, and

- P is a number between 2 and 10.

Other examples of transfer agents are transfer agents of the following formulas (II) and (III):

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- R¹ is an organic group, eg a group R¹ as defined above for the transfer agents of formulas (I), (IA), (IB) and (IC), - R², R³, R⁴, R⁷ and R⁸ which are identical or different are hydrogen atoms or organic groups, optionally forming rings. Examples of organic groups R², R³, R⁴, R⁷ and R⁸ include hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl and hydrocarbyl containing a substituted heteroatom. According to the above process, if all the successive polymerizations are carried out in the same reactor, it is generally preferable for all the monomers used during one step to have been consumed before the polymerization of the following stage begins, therefore before the new monomers are introduced. However, it may happen that monomers of the preceding stage are still present in the reactor during the polymerization of the following block. In this case, these monomers generally do not represent more than 5 mol% of all the monomers and they participate in the following polymerization by contributing to the introduction of other reasons in the next block.

The polymerization can be carried out in an aqueous and / or organic medium. The polymerization can also be carried out in substantially pure melted form (bulk polymerization), or as the latex type process in an aqueous medium.

The block copolymer may be in solid form and / or dried. It can also be in solution in an organic solvent. It can also be in the form of a dispersion in aqueous medium in a latex form. It usually depends on the process used for its preparation. If not in solid form and / or dried, the solvent or aqueous medium is usually intended to be removed to obtain the solid form block copolymer and / or dried. For example, the solvent or the aqueous medium may be removed by evaporation or drying, once the solution or latex dispersion was coated on a surface to obtain a film or a coating, in a solid form and / or dried. If it is in solid form, the block copolymer of the invention may be molten, to be formed or applied on a surface. Then it can be cooled to form an article, film or solid coating.

It is believed that when it is in solid or dried form, the soft block of the block copolymer according to the invention forms a soft phase and the continuous or rigid blocks form a rigid phase, the rigid phase being dispersed in the soft phase. As explained above and without wishing to be bound by any theory, it is believed that the phase separation provides cohesion by crosslinking according to a physical phenomenon. When it is in solid or dried form, the block copolymer of the invention has an elastomeric property and a thermoplastic property. May be designated thermoplastic elastomer.

Thus, the block copolymer of the invention has in a solid or dried form, an elongation at break of at least 500% and a tensile strength of at least 1.5 MPa. Preferably, the elongation at break is at least 750% and the tensile strength is at least 2.0 MPa. These properties are considered the properties of an elastomer compound.

The block copolymers of the invention find use in many areas. They can be used for example for the articles of manufacture. The block copolymers according to the invention are for example in the form of powders, pellets, solid granules, optionally compounded with other ingredients to be melted, introduced into a mold in a liquid form and then cooled to obtain an article in a form solid. The articles obtained from block copolymers usually have an interesting touch, which can be called soft or sticky (compared to other thermoplastics) ... items made from block copolymers according to the invention also have elastomeric properties that can be required. The thermoplastic properties allow to manufacture articles having elastomeric properties with shapes that would be difficult to achieve with a polymer or a composition that would require chemical crosslinking. They can simplify the process of making elastomeric articles or simplify the compositions used to make such articles. It should be noted that for manufacturing articles, the block copolymer can be used alone or with certain other ingredients, as a compound in an engineering plastic formulation. Depending on the amount of the various ingredients, the block copolymer may be considered as an additive to modify properties of other polymers or as a polymer having properties modified by other ingredients. the copolymer is further mention may comprise units which enhance compatibility with other compounds of a composition as units comprising an epoxy group or a maleic anhydride group. Useful groups are known to those skilled in the art thermoplastic formulations.

Some block copolymers of the invention can be used as adhesive compounds. They can be used as a component in an adhesive composition. Block copolymers wherein the soft monomer is butyl acrylate or butyl methacrylate are specifically preferred for use as an adhesive compound. the copolymer is further mention may comprise units which enhance the adhesion properties or compatibility with other compounds such as units comprising an epoxy group or a maleic anhydride group. Useful groups are known to those skilled in the art adhesive compositions. For example, the block copolymers according to the invention or compositions comprising said block copolymers, preferably block copolymers in which the soft monomer is butyl acrylate or butyl methacrylate, can be deposited on a surface in molten form in the form of a solution or as a latex dispersion in an aqueous medium to obtain an adhesive layer. The surface is for example a base layer, forming an adhesive tape, along with an adhesive layer. Therefore, the surface on which the composition is deposited may for example be a plastic film or a paper product.

The block copolymer of the invention may be included in formulations intended to be applied on a surface, used in the construction of the building or in the layout of the house, such as paint formulations (industrial paints, household paints or decorative). The block copolymer can also be included in a sealant, cement or filler formulation. The formulations in which the block copolymer is in the form of a latex dispersion are particularly preferred. While the dispersion is not too viscous in paints, the viscosity of the putty, cement or filler formulation is usually quite high. The block copolymer can give a coating or paint layer having certain specific properties related to the elasticity as crack resistance, impact resistance, resistance to brands, resistance to deposition of dirt ... Mastics, cements or fillers comprising the block copolymer according to the invention have improved properties compared with mastics, cements or fillers comprising based acid ester polymers (meth) acrylic acid. This so-called crosslinking by an aforementioned physical phenomenon makes the use of copolymers particularly useful sequences as there is no need to carry out cross-linking step once the formulation has been applied to a surface or using complex formulations, very sensitive or harmful to the environment or health (formulations two packs, formulation comprising a catalyst that is inhibited in the presence of water ...). This so-called cross-linking by a physical phenomenon can also control the flow properties and adhesion. Some illustrative but not limiting examples are given hereinafter for a better understanding of the invention.

Example 1: diblock copolymer r_olv (styrene / methacrylic acid) -block-poly (ethyl acrylate / methacrylic acid) (St / MMA -b (EtA / MMA where St / MMA = 80/20 EtA / MMA = 95/5

Step 1: Synthesis of a random block (St / MMA), styrene (St and methacrylic acid (MMA with a weight of Sτ / MAA = 80/20.

Polymerization was carried out under emulsion conditions in a jacketed reactor equipped with a stainless steel stirrer with three blades. 300 g of water, 7.46 g of sodium dodecyl sulfate (Aldrich) and 1.87 g of sodium carbonate Na₂CO₃ are introduced at ambient temperature as a mixture of departure. The resulting mixture is stirred for 30 minutes (190 rev / min) during this time, the temperature was raised to 75 ° C. Then, a mixture comprising 3.00 g of styrene, 1.56 g of α- (o-ethylxanthyl) propionate methyl

(CH₃CHCO₂Me) SCSOEt and 0.75 g of methacrylic acid is incorporated. The temperature is subsequently raised to 85 ° C and 0.31 g of ammonium persulfate (NH₄)₂S₂O₈ has been added. After five minutes, the addition was followed by 27.0 g of styrene, 6.75 g of methacrylic acid over one hour. Once the addition was completed, a copolymer emulsion was obtained (latex) maintained at 85 ° C for one hour.

Step 2: Synthesis of a random block (EtA / MMA-ethyl acrylate (EtA and methacrylic acid (MMA) with a weight ratio: EtA MAA = 95/5 to obtain a diblock.

58.12 g of the copolymer emulsion obtained previously are removed from the reactor. 0.13 g of ammonium persulphate (NH)₂S₂O₈ and 5.0 g of water are added to the remaining emulsion in the reactor to 85 ° C. After five minutes, we started the next addition of a mixture comprising:

- 363.78 g of ethyl acrylate (EtA) and

- 19.15 g of methacrylic acid (MAA) and simultaneously of another mixture comprising:

- 385 g of water and - l, 06 g of Na₂CO₃.

The addition lasts 1 hour. The system was maintained at this temperature for an additional three hours. The block of the calculated molecular weight (St / MMA) is 5000 g / mol and the calculated molecular weight of the block (EtA / MMA) is 62 500 g / mol.

Example 2: triblock Poly (styrene / methacrylic acid) -block-poly (ethyl acrylate / acid méthacryliqueVbloc polyfstyrène / methacrylic acid) (St / MMA b- (EtA -b- (St / MMA) where St / MMA ≈ 80/20 in the first block. St / MMA = 98/2 in the third block and EtA / MMA 95/5 Step 1: Synthesis of a first random block (St / MMA), styrene (Si) and methacrylic acid (MAA) with a weight ratio of St / MAA = 80/20.

Polymerization was carried out under emulsion conditions in a jacketed reactor equipped with a stainless steel stirrer with three blades. 300 g of water, 7.46 g of sodium dodecyl sulfate (Aldrich) and 1.87 g of sodium carbonate Na CO₃ are introduced at ambient temperature under starting mixture form. The resulting mixture is stirred for 30 minutes (190 rev / min) during this time, the temperature was raised to 75 ° C. Then, a mixture comprising 3.00 g of styrene, 1.56 g of α- (o-ethylxanthyl) propionate methyl (CH₃CHCO₂Me) SCSOEt and 0.75 g of methacrylic acid is incorporated. The temperature is subsequently raised to 85 ° C and 0.31 g of ammonium persulfate (NH₄)₂S₂O₈ has been added. After five minutes, the addition was followed by 27.0 g of styrene, 6.75 g of methacrylic acid over one hour. Once the addition was completed, a copolymer emulsion was obtained (latex) maintained at 85 ° C for one hour.

Step 2: Synthesis of a second statistic block (EtA / MMA) of ethyl acrylate (EtA) and methacrylic acid (MMA) with a weight ratio: EτA / MAA = 95/5 to obtain a diblock . 58.12 g of the copolymer emulsion obtained previously are removed from the reactor. 0.13 g of ammonium persulfate (NH₄)₂S₂O₈ and 5.0 g of water are added to the remaining emulsion in the reactor to 85 ° C. After five minutes, we started the next addition of a mixture comprising:

- 363.78 g of ethyl acrylate (EtA) and - 19.15 g of methacrylic acid (MAA) and simultaneously of another mixture comprising:

- 385 g of water and - l, 06 g of a₂CO₃.

The addition lasts 1 hour. The system was maintained at this temperature for an additional three hours. This gives a copolymer emulsion (latex). Step 3: Synthesis of a third random block (St / MMA), styrene (St) and methacrylic acid (MMA ') with a weight ratio: St / MAA = 98/2 to obtain a triblock copolymer.

212.94 g of the copolymer emulsion obtained previously are removed from the reactor. 0.05 g of ammonium persulphate (NH)₂S₂O₈ and 4.0 g of water are added to the remaining emulsion in the reactor to 85 ° C. After five minutes, we started the next addition of a mixture comprising:

- 24.02 g of styrene (St) and

- 0.49 g of methacrylic acid (MAA) and simultaneously of another mixture comprising:

- 32.0 g of water and - 0.03 g Dena₂CO₃.

The addition lasts 1 hour. The system was maintained at this temperature for an additional three hours. This gives a copolymer emulsion (latex). calculated molecular weight of the first block (St / MMA) is

5000 g / mol, the molecular weight of the second calculating block (EtA / MMA) is 62 500 g / mol and the molecular weight calculated from the third block (St / MMA) is 500 g / mol.

Example 3 (comparative) diblock poly (styrene / methacrylic acid) -block-poly (ethyl acrylate / methacrylic acid) (St / MMA) -b (EtA / MMA) where St / MMA = 96 *** / 4 and EtA / MMA 95/5

Step 1: Synthesis of a random block (St / MMA), styrene (St) and methacrylic acid (MAA) with a weight ratio of St / MAA = * 96/4.

Polymerization was carried out under conditions of emulsion in a jacketed reactor equipped with a stainless steel stirrer with three blades. 450 g of water, 9.32 g of sodium dodecyl sulfate (Aldrich) and 0.38 g of sodium carbonate Na₂CO₃ are introduced at ambient temperature under starting mixture form. The resulting mixture is stirred for 30 minutes (190 rev / min) during this time, the temperature was raised to 75 ° C. Then, a mixture comprising 4.50 g of styrene, 1.95 g of α- (o-ethylxanthyl) propionate methyl (CH₃CHCO₂Me) SCSOEt and 0.19 g of methacrylic acid is incorporated. The temperature is subsequently raised to 85 ° C and 2.28 g of ammonium persulfate (NH₄)₂S₂O₈ were added. After five minutes, the addition was followed by 40.5 g of styrene, 1.69 g of methacrylic acid over one hour. Once the addition was completed, a copolymer emulsion was obtained (latex) maintained at 85 ° C for one hour.

Step 2: Synthesis of a random block (EtA / MMA) of ethyl acrylate (EtA) and methacrylic acid (MMA) with a weight ratio: EtA / MAA * = 95/5 to obtain a diblock .

113.51 g of the copolymer emulsion obtained previously are removed from the reactor. 0.17 g of ammonium persulphate (NH) S₂O₈ and 7.0 g of water are added to the remaining emulsion in the reactor to 85 ° C. After five minutes, we started the next addition of a mixture comprising: - 424.41 g of ethyl acrylate (EtA) and

- 22.34 g of methacrylic acid (MAA) and simultaneously of another mixture comprising:

- 385 g of water and

- L, 06 g of Na₂CO₃. The addition lasts 1 hour. The system was maintained at this temperature for an additional three hours.

The block of the calculated molecular weight (St / MMA) is 5000 g / mol and the calculated molecular weight of the block (EtA / MMA) is 62 500 g / mol.

Example 4 (Comparative) triblock Poly (styrene / methacrylic acid) -block-poly (ethyl acrylate / methacrylic acid) -block-poly (styrene / methacrylic acid) (St / MMA) -b- (EtA / MMA ) -b (St / MMA) where St / MMA = 80/20 in the first block. St / MMA = 95/5 in the third block and EtA / MMA 95/5

Step 1: Synthesis of a random block (St / MMA), styrene (St) and methacrylic acid (MAA) with a weight ratio of St / MAA = * 96/4. Polymerization was carried out under conditions of emulsion in a jacketed reactor equipped with a stainless steel stirrer with three blades. 450 g of water, 9.32 g of sodium dodecyl sulfate (Aldrich) and 0.38 g of sodium carbonate Na₂CO₃ are introduced at ambient temperature under starting mixture form. The resulting mixture is stirred for 30 minutes (190 rev / min) during this time, the temperature was raised to 75 ° C. Then, a mixture comprising 4.50 g of styrene, 1.95 g of - (O-ethylxanthyl) propionate methyl

(CH₃CHCO₂Me) SCSOEt and 0.19 g of methacrylic acid is incorporated. The temperature is subsequently raised to 85 ° C and 2.28 g of ammonium persulfate (NH₄)₂S₂O₈ were added. After five minutes, the addition was followed by 40.5 g of styrene, 1.69 g of methacrylic acid over one hour. Once the addition was completed, a copolymer emulsion was obtained (latex) maintained at 85 ° C for one hour.

Step 2: Synthesis of a random block (EtA / MMA) of ethyl acrylate (EtA) and methacrylic acid (MMA) with a weight ratio: EtA / MAA = 95/5 to obtain a diblock.

113.51 g of the copolymer emulsion obtained previously are removed from the reactor. 0.17 g of ammonium persulphate (NH) S₂O₈ and 7.0 g of water are added to the remaining emulsion in the reactor to 85 ° C. After five minutes, we started the next addition of a mixture comprising:

- 424.41 g of ethyl acrylate (EtA) and

- 22.34 g of methacrylic acid (MAA) and simultaneously of another mixture comprising: - 385 g of water and

- L, 24 g of Na₂CO₃.

The addition lasts 1 hour. The system was maintained at this temperature for an additional three hours. This gives a copolymer emulsion (latex).

Step 3: Synthesis of a third random block (St / MMA), styrene (St) and methacrylic acid (MMA) with a weight ratio: St / MAA = 95/5 to obtain a triblock copolymer. 353.55 g of the copolymer emulsion obtained previously are removed from the reactor. 0.07 g of ammonium persulphate (NH)₂S₂O₈ and 5.0 g of water are added to the remaining emulsion in the reactor to 85 ° C. After five minutes, we started the next addition of a mixture comprising: - 24.25 g of styrene (St) and

- 1.28 g of methacrylic acid (MAA) and simultaneously of another mixture comprising:

- 32.5 g of water and

- 0.07 g of Na₂CO₃. The addition lasts 1 hour. The system was maintained at this temperature for an additional three hours.

The molecular weight calculated from the first block (St / MMA) is 5000 g / mol, the second block calculated molecular weight (EtA / MMA) is 62 500 g / mol and the molecular weight calculated from the third block ( St / MMA) is 500 g / mol.

EXAMPLE 5 triblock poly (styrene / methacrylic acid) -block-poly (ethyl acrylate / methacrylic acid) -block-poly (styrene / methacrylic acid) (St / MMA) -b- (EtA / MMA) -b - (Sτ / MMA) where St / MMA = 80/20 in the first block. St / MMA = 98/2 in the third block and EtA / MMA 95/5

Step 1: Synthesis of a first random block (St / MMA), styrene (St) and methacrylic acid (MAA) with a weight ratio of St / MAA = 80/20.

Polymerization was carried out under conditions of emulsion in a jacketed reactor equipped with a stainless steel stirrer with three blades. 555 g of water, 12.05 g of sodium dodecyl sulfate (Aldrich) and 1.50 g of sodium carbonate Na₂CO₃ are introduced at ambient temperature under starting mixture form. The resulting mixture is stirred for 30 minutes (190 rev / min) during this time, the temperature was raised to 75 ° C. Then, a mixture comprising 3.00 g of styrene, 2.60 g of α- (o-ethylxanthyl) propionate methyl (CH₃CHCO₂Me) SCSOEt and 0.75 g of methacrylic acid is incorporated. The temperature is subsequently raised to 85 ° C and 0.52 g of ammonium persulfate (NH₄)₂S₂O₈ has been added. After five minutes, the addition was followed by 27.0 g of styrene, 6.75 g of methacrylic acid over one hour. Once the addition was completed, a copolymer emulsion was obtained (latex) maintained at 85 ° C for one hour.

Step 2: Synthesis of a second random block (EtA / MMA) of ethyl acrylate (EtA) and methacrylic acid (MMA) with a weight ratio: EtA / MAA = 95/5 to obtain a diblock .

101.53 g of the copolymer emulsion obtained previously are removed from the reactor. 0.22 g of ammonium persulfate (NH₄)₂S₂O₈ and 5.0 g of water are added to the remaining emulsion in the reactor to 85 ° C. After five minutes, we started the next addition of a mixture comprising:

- 606.3 g of ethyl acrylate (EtA) and

- 31.91 g of methacrylic acid (MAA) and simultaneously of another mixture comprising:

- 512.5 g of water and - 77 g of Na₂CO₃.

The addition lasts 1 hour. The system was maintained at this temperature for an additional three hours. This gives a copolymer emulsion (latex).

Step 3: Synthesis of a third random block (St / MMA), styrene (St) and methacrylic acid (MMA) with a weight ratio: St / MAA = 98/2 to obtain a triblock copolymer.

333.07 g of the copolymer emulsion obtained previously are removed from the reactor. 0.09 g of ammonium persulphate (NH)₂S₂O₈ and 4.0 g of water are added to the remaining emulsion in the reactor to 85 ° C. After five minutes, we started the next addition of a mixture comprising:

- 4.0 g of styrene (St) and

- 0.08 g of methacrylic acid (MAA) and simultaneously of another mixture comprising:

- 40.0 g of water and - 0.005 g of Na₂CO₃. The addition lasts 1 hour. The system was maintained at this temperature for an additional three hours.

The molecular weight calculated from the first block (St / MMA) is 3000 g / mol, the second block calculated molecular weight (EtA / MMA) is 62 500 g / mol and the molecular weight calculated from the third block ( St / MMA) is 500 g / mol.

Example 6 (Comparative) triblock of poly (styrene / méthacryliqueVbloc- acid poly (ethyl acrylate / methacrylic acid) -block-poly (styrene / methacrylic acid) (Sτ / MMA) -b- (EtA / MMA) -b - (St / MMA) where St / MMA = 98/2 in the first block St / MMA = 98/2 in the third block and EtA / MMA 95/5.

Step 1: Synthesis of a first random block (St / MMA), styrene (St) and methacrylic acid (MAA) with a weight ratio of St / MAA = 98/2. Polymerization was carried out under conditions of emulsion in a jacketed reactor equipped with a stainless steel stirrer with three blades. 660 g of water, 7.54 g of sodium dodecyl sulfate (Aldrich) and 0.31 g of sodium carbonate Na₂CO₃ are introduced at ambient temperature under starting mixture form. The resulting mixture is stirred for 30 minutes (190 rev / min) during this time, the temperature was raised to 75 ° C. Then, a mixture comprising 6.82 g of styrene, 4.65 g of α- (o-ethylxanthyl) propionate methyl (CH₃CHCO₂Me) SCSOEt and 0.17 g of methacrylic acid is incorporated. The temperature is subsequently raised to 85 ° C and 1.39 g of ammonium persulfate (NH₄)₂S₂O₈ has been added. After five minutes, the addition was followed by 58.8 g of styrene, 1.57 g of methacrylic acid over one hour. Once the addition was completed, a copolymer emulsion was obtained (latex) maintained at 85 ° C for one hour.

Step 2: Synthesis of a second statistic block (EtA / MMA) of ethyl acrylate (EtA) and methacrylic acid (MMA) with a weight ratio: EtA / MAA = 95/5 to obtain a diblock . 67.66 g of the copolymer emulsion obtained previously are removed from the reactor. 0.46 g of ammonium persulfate (NH₄)₂S₂O₈ and 12 g of water are added to the remaining emulsion in the reactor to 85 ° C. After five minutes, we started the next addition of a mixture comprising: - 387.96 g of ethyl acrylate (EtA) and

- 7.91 g of methacrylic acid (MAA) and simultaneously of another mixture comprising:

- 96 g of water and - 0.44 g of Na₂CO₃. The addition lasts 1 hour. The system was maintained at this temperature for an additional three hours. This gives a copolymer emulsion (latex).

Step 3: Synthesis of a third random block (St / MMA), styrene (St) and methacrylic acid (MMA) with a weight ratio: Sτ / MAA = 98/2 to obtain a triblock copolymer.

392.67 g of the copolymer emulsion obtained previously are removed from the reactor. 0.05 g of Na2CO3 in 5 g of water is added to the remaining emulsion in the reactor. 0.29 g of ammonium persulphate (NH)₂S₂O₈ and 10.0 g of water are added at 85 ° C. After five minutes, we started the next addition of a mixture comprising:

- 7.33 g of styrene (St) and

- 0.15 g of methacrylic acid (MAA).

The addition lasts 1 hour. The system was maintained at this temperature for an additional three hours. Calculated molecular weight of the first block (St / MMA) is to e

3000 g / mol, the second block of the calculated molecular weight (EtA / MMA) is 19 500 g / mol and the molecular weight calculated from the third block (St / MMA) is 500 g / mol.

Some characteristics of the block copolymers of the examples are shown in Table 1. Table 1

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Example 7: Testing of stretching / stress

The films of the block copolymers of the preceding examples are cast and dried in a silicon matrix at room temperature for two days, then cured in the oven at 50 ° C for 24 hours and finally at 75 ° C for 2 hours. The resultant film is about 1 mm thick. The strips 4 cm long and 2 cm wide are cut to form films to achieve the mechanical tests.

It performs a stretching experience / strain with a INSTRON 5543. A constant strain rate is applied with a fixed elongation rate of 2 mm / s. Stretching is measured on the elongation (stretching curve / strain). The maximum elongation possible with this unit is 3000%.

The following different behaviors are reported:

Elastic behavior: constant increase in the stretch and sudden rupture in a critical stretch. Stretching (in megapascals: MPa) and the elongation (in%) at break are reported.

Plastic behavior: no break below 3000% strain, maximum stress observed at a value of low stretch in the curve stretch / stress and flow behavior with a stress decrease with an increase in deformation. There is no rupture, the sample flows. Only the maximum of the curve stretch / stress (megapascals: MPa) was postponed.

The results are shown in Table 2.

Table 2

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Example 8: Dynamic Mechanical Analysis Test (DMA) was carried out of the dynamic mechanical analyzes of block copolymer films. The glass transition of the soft block, the modulus of elasticity of the elastic plate and the fusion of this block (T_g high) were measured. Complex modules (in Pa) block polymers are measured at different temperatures (the temperature rises) at a constant frequency of 1 Hz. The device used is a Universal V3. IB TA Instruments, using a method of increasing temperatures / single frequency. The geometry is either sheared or extensional. A first reduction of the complex modulus as the temperature increases, typically 10⁹ Pa to 10⁶ Pa, is considered for the T_g the flexible block. Then, the module is constant with increasing temperature (elastic plate). The constant modulus is reported as the elastic plate module. Then it drops sharply again when it reaches the temperature considered for the T_g high polymer. This temperature more high is regarded as corresponding to the melting of the polymer (thermoplastic property). The results are shown in Table 3.

Table 3

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The polymers of Comparative Examples 3, 4 and 6 do not exhibit elastomeric behavior. The cohesion of the polymer is low. The polymers flow. They have a poor thermoplastic behavior. The polymers of Examples 1, 2 and 5 have a high elastomeric behavior and a thermoplastic behavior. The elastomeric properties are good if the same molecular weight of this block is low (5000 g / mol for the polymers according to Examples 1 and 2) and even very low (3000 g / mol for the polymers according to Example 5).