Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F293/00—Macromolecular compounds obtained by polymerisation on to a macromolecule having groups capable of inducing the formation of new polymer chains bound exclusively at one or both ends of the starting macromolecule
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/44—Preparation of metal salts or ammonium salts

Definitions

• the present invention relates to modulatable block copolymers which can be used, in particular in adhesive compositions, such as hot-melt adhesive pressure-sensitive compositions (also known as HMPSA), and in thermoplastic compositions.
• adhesive compositions such as hot-melt adhesive pressure-sensitive compositions (also known as HMPSA)
• thermoplastic compositions used in particular in tape and adhesive label applications must have a compromise of properties between their implementation (thermal stability, viscosity level, etc.) and their properties. physical (adhesion, cohesion and temperature resistance ). It is generally the same for thermoplastic compositions.
• the invention relates, according to a first object, to a block copolymer, ethylenic, linear comprising:
• At least one first block A having a glass transition temperature greater than 20 ° C., preferably greater than 60 ° C.
• At least one second block B having a glass transition temperature of less than 15 ° C., preferably less than -30 ° C. at least one third C sequence having a glass transition temperature greater than 20 ° C., preferably greater than 60 ° C .; said first sequence A and third block C being identical or different and at least one of them comprising at least one monomeric unit comprising at least one -CO 2 H and / or carboxylate -C00 "function .
• Such copolymers are particularly advantageous, in the sense that it is easily conceivable with these to modulate their physical properties, such as thermomechanical properties and rheological properties, by controlling the degree of neutralization of the functions -CO 2 H.
• their glass transition temperature increases, and the ionic interactions make it possible to create electrostatic bridges between the polymer chains, which influences their mechanical strength.
• copolymers of the invention it is also possible by neutralizing all or part of the acid functional groups -CO 2 H to control the melt viscosity and thus to selectively increase the low shear rate viscosity (for a better creep resistance, for example) while having a much more moderate increase in viscosity for high shear gradients.
• the copolymers of the invention are of particular interest for formulations comprising a solvent, since control of the viscosity in these formulations can be crucial (especially for example, to maintain solid particles in stable suspension).
• the copolymers can be easily incorporated with other ingredients commonly encountered in adhesive and thermoplastic compositions.
• copolymers of the invention are linear block ethylenic copolymers.
• ethylenic copolymer is meant a copolymer obtained by polymerization of monomers comprising ethylenic unsaturation.
• block copolymer is meant a copolymer comprising several distinct successive sequences (in this case, in our case, at least three), that is to say of different chemical natures.
• the copolymers of the invention are polymers with a linear structure.
• a nonlinearly structured polymer is, for example, a branched, star-shaped, grafted, or other polymer.
• all the monomers used to prepare a linear polymer are monofunctional, that is to say have only one polymerizable function.
• the polymerization initiators may, for their part, be monofunctional or difunctional.
• the copolymers comprise respectively a first sequence A and a third sequence C, which are identical or different, both having respectively a glass transition temperature greater than 20 ° C., at least one of its sequences comprising at least one monomer unit comprising at least one function -CO 2 H and / or -COO ".
• these monomer units are included in the sequence given in a content ranging from 0.5 to 99 mol%, preferably from 3 to 30% more preferably 3 to 20 mol%
• a monomer unit is understood to mean a unit directly derived from a monomer after polymerization thereof.
• the monomers giving rise, after polymerization, to monomeric units comprising at least one --CO 2 H function that may be used may be chosen from the monomers corresponding to the following formula (I) :
• R 1 is a hydrogen atom or a linear or branched hydrocarbon group of type C p H 2p + 1, with p being an integer ranging from 1 to 12;
• Z is a divalent group selected from -COO-, -CONH-, -CONCH 3 -, -OCO- or -O-; preferably -COO- and -CONH-; x is an integer equal to 0 or 1, preferably 1;
• R 2 is a saturated or unsaturated, optionally aromatic, linear, branched or cyclic divalent carbon group comprising from 1 to 30 carbon atoms and may comprise from 1 to 30 heteroatoms chosen from O, N, S, and P;
• R 1 is a hydrogen atom or a methyl group
• x is equal to 0
• m is equal to 0.
• the one or more heteroatoms when present, may be inserted in the chain of said group R 2 , or said group R 2 may be substituted by one or more groups including them, such as a hydroxyl group or amino (NH 2 , NHR 'or NR' R "with R 'and R", identical or different, representing a linear or branched C 1 -C 22 alkyl group, especially a methyl or ethyl group).
• R 2 can be:
• alkylene group such as a methylene, ethylene, propylene, n-butylene, isobutylene, tert-butylene, n-hexylene, n-octylene, n-dodecylene, n-octadecylene, n-tetradecylene, n-docosanylene group;
• a phenylene-C 6 H 4 - (ortho, meta or para) group optionally substituted with a C 1 -C 12 alkyl group optionally comprising from 1 to 8 heteroatoms chosen from O, N, S, and P; or benzylene -C 5 H 4 -CH 2 - optionally substituted by alkyl, Ci-Ci 2 optionally comprising 1 to 8 heteroatoms selected from 0, N, S, and P;
• Ri, Z, x, R 2 and m have the same meanings as in formula (I) above;
• X 1+ is a divalent group of formula -N + R ' 5 R' 7 with R '6 and RZ 7 representing, independently of one another,
• a hydrogen atom (i) a linear, branched or cyclic, optionally aromatic, alkyl group comprising from 1 to 30 carbon atoms, which may comprise from 1 to 8 heteroatoms selected from O, N, S and P; for example a methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl or isobutyl group;
• R ' 6 and R' 7 may form with the nitrogen atom a saturated or unsaturated, optionally aromatic ring (NR ' 5 R' 7 or R ' 5 NR' 7 ) comprising in total 5, 6, 7 or 8 atoms, and especially 4, 5, 6 or 7 carbon atoms and / or 2 to 4 heteroatoms selected from 0, S and N; said cycle being fusible with one or more other rings, saturated or unsaturated, optionally aromatic, each comprising 5, 6, 7 or 8 atoms, and in particular 4, 5, 6 or 7 carbon atoms and / or 2 to 4 selected heteroatoms among 0, S and N;
• R 3 is a saturated or unsaturated, optionally aromatic, linear, branched or cyclic divalent carbon group comprising from 1 to 30 carbon atoms, which may comprise from 1 to 18 heteroatoms chosen from O, N, S and P;
• n is an integer equal to 0 or 1.
• the heteroatom (s), when they are present, may be inserted in the chain of said R 3 group, or said R 3 group may be substituted by one or several groups including them such as hydroxy or amino; in particular R 3 can be:
• an alkylene group such as a methylene, ethylene, propylene, n-butylene, isobutylene, tert-butylene, n-hexylene, n-octylene, n-dodecylene, n-octadecylene, n-tetradecylene, n-docosanylene group; a phenylene-C 6 H 4 - (ortho, meta or para) group optionally substituted with a C 1 -C 12 alkyl group optionally comprising from 1 to 5 heteroatoms chosen from O, N, S, F, Si and P; or benzylene group -C 6 H 4 -CH 2 - optionally substituted by alkyl, Ci-Ci 2 optionally comprising 1 to 5 heteroatoms selected from 0, N, S and P.
• a phenylene-C 6 H 4 - (ortho, meta or para) group optionally substituted with a C 1 -C 12
• the A and / or C sequences may comprise one or more monomer units derived from additional monomers chosen from hydrophilic nonionic monomers, hydrophobic monomers and their mixtures.
• These additional monomers may be identical or different from one sequence to another.
• this or these additional monomers are ethylenic monomers copolymerizable with the ionic hydrophilic monomer or monomers, whatever their coefficient of reactivity.
• the nonionic hydrophilic monomers may be present in a proportion of from 0 to 98% by weight, relative to the weight of the block, in particular from 2 to 95% by weight, and still more preferably from 3 to 92% by weight, in at least one sequence, or even in each sequence.
• the hydrophobic monomers may be present in a proportion of from 0 to 98% by weight, relative to the weight of the block, in particular from 2 to 95% by weight, and still more preferably from 3 to 92% by weight, in at least a sequence, even in each sequence.
• hydrophilic non-ionic or hydrophobic monomers that can be copolymerized with the precursor monomers of monomer units carrying COH 2 functions mentioned above to form the polymers according to the invention, mention may be made, alone or as a mixture, of:
• R 2 is a hydrogen atom or a methyl group (CH 3 ) and R 3 represents:
• a linear or branched alkyl group comprising from 1 to 30 carbon atoms, in which one or more heteroatoms chosen from O, N, S and P are optionally intercalated; said alkyl group may further be optionally substituted with one or more substituents selected from OH, halogen atoms (Cl, Br, I and F), and -Si (R ' 4 R' 5 R 'e and -Si (R ' 4 R' 5) O, in which R ' 4 , R' 5 and R '5, which may be identical or different, represent a hydrogen atom, a Ci-C 6 alkyl group or a group phenyl; in particular R 3 may be methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, hexyl, ethylhexyl, especially ethyl-2-hexyl, octyl, lauryl, isoocty
• a C 3 to C 20 aryl group such as phenyl
• a C 4 to C 30 aralkyl group such as a 2-phenylethyl, t-butylbenzyl group; or benzyl
• heterocyclic group comprising from 4 to 12 ring members containing one or more heteroatoms chosen from O, N and S, the ring being aromatic or not,
• a heterocycloalkyl (alkyl of 1 to 4 carbon atoms) group such as a furfurylmethyl or tetrahydrofurfurylmethyl group, said cycloalkyl, aryl, aralkyl, heterocyclic or heterocycloalkyl groups possibly being substituted by one or more substituents chosen from hydroxyl groups, halogen atoms, and alkyl groups Ci-C 4 linear or branched, in which is (are) optionally intercalated (s) one or more heteroatoms selected from 0, N, s and P, said alkyl groups, in addition, optionally substituted with one or more substituents selected from -OH, halogen atoms (Cl, Br, I and F), and -Si groups (R ' 4 R' 5 R'e) and -Si (R ' 4 R' 5 ) O, in which R ' 4 , RZ 5 and R' 5 , which are identical or different, represent a hydrogen atom, a C
• R 8 is H or methyl; and R 7 and R 5 , which may be identical or different, represent: a hydrogen atom; or
• alkyl group comprising from 1 to 30 carbon atoms, in which one or more heteroatoms chosen from O, N, S and P are optionally intercalated; said alkyl group may further be optionally substituted by one or more substituents selected from -OH, halogen atoms (Cl, Br, I and F), and -Si groups;
• R '5 represent a hydrogen atom, an alkyl group with C 5 or phenyl; in particular, R 5 and R 7 may be methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, hexyl, ethylhexyl, octyl, lauryl, isooctyl, isodecyl, dodecyl, cyclohexyl, t-butylcyclohexyl or stearyl; ethyl-2-perfluorohexyl, ethyl-2-perfluorooctyl; or a C1-4 hydroxyalkyl group such as 2-hydroxyethyl, 2-hydroxybutyl and
• aryl group such as phenyl
• a C 4 to C 30 aralkyl group such as a 2-phenylethyl, t-butylbenzyl or benzyl group,
• heterocyclic group of 4 to 12 members containing one or more heteroatoms chosen from O, N and S, the ring being aromatic or not,
• a heterocycloalkyl (C 1 -C 4) alkyl group such as a furfurylmethyl or tetrahydrofurfurylmethyl group, said cycloalkyl, aryl, aralkyl, heterocyclic or heterocycloalkyl groups possibly being substituted by one or more substituents chosen from hydroxyl groups, halogen, and linear or branched C 1 -C 4 alkyl groups in which one or more heteroatoms selected from O, N, S and P are optionally intercalated, said alkyl groups being furthermore optionally substituted with one or more substituents chosen among -OH, the halogen atoms (Cl, Br, I and F), and the groups -Si (R ' 4 R' 5 R ' 6 ) and -Si (R' 4 R ' 5 ) O, in which R '4, R' 5 and R '5, identical or different, represent a hydrogen atom, an alkyl group -C 6 or phenyl;
• Examples of such additional monomers are (meth) acrylamide, N-ethyl (meth) acrylamide, N-butylacrylamide, N-t-butylacrylamide,
• N-isopropylacrylamide N, N-dimethyl (meth) acrylamide, N, N-dibutylacrylamide, N-octylacrylamide,
• R 9 is a hydroxyl group; a halogen (Cl or F); an NH 2 group; a group -OR 0 wherein Rio represents a phenyl group or an alkyl group Ci-Ci 2 (the monomer is a vinyl or allylic ether); an acetamide group (NHCOCH 3 ); OCORn a group wherein Rn represents an alkyl group of 2 to 12 carbons, linear or branched (the monomer is a vinyl ester or allyl), cycloalkyl C 3 -C 2 aryl, C 3 -C 20 or in arallyle C 4 -C 30 ; or else R 9 is chosen from: a linear or branched alkyl group comprising from 1 to 30 carbon atoms, in which one or more heteroatoms chosen from O, N, S and P are optionally intercalated; said alkyl group may further be optionally substituted by one or more substituents selected from -OH, halogen
• R '5 identical or different, represent a hydrogen atom, an alkyl group -C 6 or phenyl
• a C 3 to C 12 cycloalkyl group such as an isobornyl or cyclohexane group
• a C 3 to C 2 aryl group such as a phenyl group
• arylalkyl or alkylaryl group such as a 2-phenylethyl or benzyl group
• heterocyclic group of 4 to 12 members containing one or more heteroatoms chosen from O, N and S, the ring being aromatic or not, such as N-vinylpyrrolidone and N-vinylcaprolactam;
• heterocycloalkyl alkyl of 1 to 4 carbon atoms
• said cycloalkyl, aryl, aralkyl, heterocyclic or heterocycloalkyl groups possibly being substituted by one or more substituents chosen from hydroxyl groups, halogen atoms, and alkyl groups from 1 to 4 linear or branched carbon atoms in which is optionally intercalated one or more heteroatoms selected from O, N, S and P, said alkyl groups may further be optionally substituted with one or more substituents selected from -OH, the halogen atoms
• R ' 4 R' 5 (R ' 4 R' 5 ) O, wherein R '4, R' 5 and R '5, which may be identical or different, represent a hydrogen atom, a C 1 -C 6 alkyl group, or a phenyl group.
• Examples of such additional monomers are vinylcyclohexane, and styrene (hydrophobic); N-vinylpyrrolidone and N-vinylcaprolactam (non-ionic hydrophilic); vinyl acetate, vinyl propionate, vinyl butyrate, vinyl ethylhexanoate, vinyl neononanoate and vinyl neododecanoate (hydrophobic); vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether. (v) the allylic compounds of formula:
• (meth) acrylamides or vinylic silicones such as methacryloxypropyltris (trimethylsiloxy) silane or
• (meth) acrylates and (meth) acrylamides of alkoxy (Cl- 4) alkyl (Cl- 4) such as (meth) acrylates and (meth) acrylamides methoxyethyl, 2-ethoxyethyl, methoxypropyl and di- (2-ethoxyethyl); more particularly 2-ethoxyethyl methacrylate; (meth) acrylamide and N, N-dimethylacrylamide;
• vinyllactams such as vinylpyrrolidone and vinylcaprolactam;
• polysaccharide (meth) acrylates such as sucrose acrylate and ethylglucoside (meth) acrylate. Mention may also be made, among the additional monomers (in particular hydrophobic) which are more particularly preferred, alone or as a mixture, for the following monomers for which the Tg is given in parenthesis by way of indication: t-butylbenzyl acrylate, acrylate t-butylcyclohexyl, isobornyl acrylate (94 ° C.), furfuryl acrylate, n-hexyl acrylate (45 ° C.), t-butyl acrylate (50 ° C.), and cyclohexyl acrylate (19 ° C.), hydroxyethyl acrylate (15 ° C.), methyl acrylate (10 ° C.), ethyl acrylate
• N-butylacrylamide N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-dibutylacrylamide, N-t-butylacrylamide and N-octylacrylamide.
• the B sequence may consist of monomeric units derived from nonionic and / or hydrophobic hydrophilic monomers as defined above. This sequence may also comprise -CO 2 H functions generally resulting from the synthesis reaction of the block copolymer.
• the copolymers of the invention are triblock copolymers, generally of ABC type, the sequences A, B and C corresponding to the same definition as that given above.
• the sequence B is present in a content ranging from 5 to 95% by weight of the copolymer, preferably in a content of greater than 50% by weight of the copolymer.
• sequence A and / or C comprises: monomeric units derived from nonionic monomers chosen from:
• H 2 C C COOR 3 with R 2 and R 3 being as defined above, such as methyl methacrylate; and monomeric units bearing at least one -CO 2 H function derived from monomers chosen from acrylic acid and methacrylic acid.
• the monomer units derived from nonionic monomers are present, for example, in a content ranging from 1 to 99.5% relative to the total weight of the sequence.
• the monomeric units carrying at least one -CO 2 H function are present, for example, in a content ranging from 0.5% to 99% relative to the total weight of the sequence.
• sequence B comprises monomer units derived from monomers chosen from (meth) acrylates of formula:
• H 2 C C COOR 3 with R 2 and R 3 being as defined above.
• sequence B may consist of monomeric units derived from n-butyl acrylate.
• Triblock copolymers according to the invention may be chosen from poly (styrene-co-methacrylic acid) -b-poly (n-butyl acrylate) -b-poly (styrene-co-methacrylic acid), poly (methacrylate) methyl-co-methacrylic acid) -b- poly (n-butyl acrylate) -b-poly (methyl methacrylate-co-methacrylic acid).
• a particular poly (styrene-co-methacrylic acid) -b-poly (n-butyl acrylate) -b-poly (styrene-co-methacrylic acid) copolymer is that for which: the poly (acrylate) block n-butyl) represents 70% by weight of the total copolymer;
• the poly (styrene-co-methacrylic acid) sequences each comprise monomeric units derived from methacrylic acid in a proportion of 2% by weight of the total copolymer and monomeric units derived from styrene at a rate of 12.5% by weight of the total copolymer;
• Poly (methyl methacrylate-co-methacrylic acid) -b-poly (n-butyl acrylate) -b- copolymer poly (methyl methacrylate-co-methacrylic acid) is that for which:
• the poly (n-butyl acrylate) block represents 35% by weight of the total copolymer;
• the poly (methyl methacrylate-co-methacrylic acid) sequences each comprise monomeric units derived from methacrylic acid in a proportion of 3.25% by weight of the total copolymer and of monomeric units derived from methyl methacrylate at 29%; 25% by weight of the total copolymer;
• Another poly (methyl methacrylate-co-methacrylic acid) -b-poly (n-butyl acrylate) -b-poly (methyl methacrylate-co-methacrylic acid) copolymer is that for which:
• the poly (n-butyl acrylate) block represents 65% by weight of the total copolymer
• the poly (methyl methacrylate-co-methacrylic acid) sequences each comprise monomeric units derived from methacrylic acid in a proportion of 1.6% by weight of the total copolymer and of monomeric units derived from methyl methacrylate at a concentration of 9% by weight of the total copolymer; a weight average molecular weight of
• the weight average molecular weight Mw of the block copolymer according to the invention is preferably greater than 10,000 g / mol, preferably greater than 50000 g / mol and less than 500 000 g / mol, preferably less than 300 000 g / mol. mol.
• the weight average molecular weight Mw of each block or block is between 5000 g / mol and 200,000 g / mol, preferably between 10,000 g / mol and 100,000 g / mol.
• the -CO 2 H acid functions can be neutralized, advantageously, with mineral bases chosen from:
• alkali hydroxides such as LiOH, NaOH, KOH;
• alkaline earth metal hydroxides such as Ca (OH) 2 ;
• hydroxides of metals such as zinc hydroxide, zinc acetate, iron hydroxide, copper hydroxide;
• hydroxides of metalloids such as aluminum hydroxide.
• the acid functions can also be neutralized with organic bases such as amines, in particular amines having a boiling point greater than 200 ° C. under 1 atmosphere.
• amines include primary, secondary or tertiary alkylamines, especially triethylamine or butylamine.
• This primary, secondary or tertiary alkylamine may comprise one or more nitrogen and / or oxygen atoms and may therefore for example include one or more alcohol functions; mention may especially be made of 2-amino-methyl-2-propanol, triethanolamine and dimethylamino-2-propanol.
• This neutralization rate can be chosen judiciously according to the desired properties.
• the degree of neutralization corresponding to the ratio between the number of moles of acid function present in one kilogram of the copolymer and the number of moles of basic functions mixed per kilogram of polymer, is advantageously greater than 0.1, preferably greater than at 0.5.
• Said polymers may be prepared according to methods known to those skilled in the art. Among these methods, mention may be made of anionic polymerization; controlled radical polymerization, for example by xanthans, dithiocarbamates or dithioesters; polymerization using nitroxide precursors; radical transfer polymerization (ATRP); group transfer polymerization.
• the block copolymers according to the invention may be obtained by so-called controlled living radical polymerization or pseudo-living polymerization, described in particular in “New Method of Polymer Synthesis", Blackie Academy & Pro fesional, London, 1995, Volume 2, page 1.
• Controlled radical polymerization refers to polymerizations for which the Secondary reactions that usually lead to the disappearance of propagating species (termination or transfer reaction) are made very unlikely compared to the propagation reaction by a free radical control agent.
• the imperfection of this mode of polymerization lies in the fact that when the concentrations of free radicals become important with respect to the concentration of monomer, the secondary reactions become again decisive and tend to widen the distribution of the masses.
• the living or pseudo-living polymerization is a polymerization for which the growth of the polymer chains ceases only with the disappearance of the monomer.
• the number average mass (Mn) increases with the conversion.
• Such polymerizations lead to copolymers whose mass dispersity is low, that is to say polymers with a mass polydispersity index (Ip) generally less than 2.
• Anionic polymerization is a typical example of living polymerization.
• Pseudo-living polymerization is, in turn, associated with controlled radical polymerization.
• controlled radical polymerization is, in turn, associated with controlled radical polymerization.
• main types of controlled radical polymerization are:
• the polymer chains of the copolymers grow simultaneously and therefore incorporate at each instant the same ratio of comonomers. All chains therefore have the same structures or similar structures, resulting in low compositional dispersity. These chains also have a low mass polydispersity index.
• the polymerization can be carried out according to the atom transfer technique (Atom Transfer Radical Polymerization or "ATRP", in English), or by reaction with a nitroxide, or even according to the technique of "reversible addition- fragmentation chain transfer "(" RAFT ”) or finally by the technique of" reverse ATRP “, known as” reverse ATRP ".
• the atom transfer radical polymerization technique consists in blocking the growing radical species in the form of a C-halide bond (in the presence of metal / ligand complex). This type of polymerization results in a control of the mass of the polymers formed and a low index of dispersity of the masses.
• atom transfer radical polymerization is carried out by polymerization of one or more radically polymerizable monomers, in the presence of:
• halogen compound comprising a transition metal capable of participating in a reduction step with one initiator and a "dormant" polymer chain, this will be called a “chain transfer agent";
• a ligand that can be chosen from compounds comprising a nitrogen atom (N), oxygen
• the halogen atom is preferably a chlorine or bromine atom.
• the technique of radical polymerization by reaction with a nitroxide consists in blocking the growing radical species in the form of a CO-NRaR type bond where Ra and Rb can be, independently of one another, an alkyl radical having 2 to 30 carbon atoms or both forming, with the nitrogen atom, a ring having from 4 to 20 carbon atoms, such as for example a 2, 2, 6, 6-tetramethylpiperidinyl ring.
• This polymerization technique is described in particular in the articles "Living free radical polymerization: a unique technique for preparation of controlled macromolecular architectures" CJ Hawker; Chem. Res. 1997,30,373-82, and "Macromolecular engineering via living free radical polymerizations" published in Macromol. Chem. Phys. 1998, vol. 199, pages 923-935, or else in application WO-A-99/03894.
• the RAFT polymerization technique is described in particular in the articles "Living free radical polymerization: a
• Dithio compounds such as dithioesters (-C (S) S-) are used for this purpose, such as dithiobenzoates, dithiocarbamates (-NC (S) S-) or dithiocarbonates (-OC (S) S-) (xanthates).
• dithioesters such as dithiobenzoates, dithiocarbamates (-NC (S) S-) or dithiocarbonates (-OC (S) S-) (xanthates).
• the molecular weight of the polymer can be varied.
• the polymerization generally takes place in several steps according to the following general scheme:
• the polymers can be purified by precipitation and then dried under vacuum,
• the polymerization of the second block consisting of a monomer or a mixture of monomers at the end of the macroinitiator is carried out.
• Steps b and c are repeated as many times as necessary depending on the number of sequences, which is the case for the production of triblock polymers of ABC type or multiblock (ABC) n with A, B and
• the chain transfer agents and solvents may be identical or different in step a) and step b).
• the block or block polymers according to the invention can also be obtained by using the conventional radical polymerization technique by sequentially casting the monomers. In this case, only the control of the nature of the sequences is possible (no control of the masses).
• the copolymers can have their physical properties (such as modulus of elastic shear, temperature resistance) modulated. It is therefore quite natural that the polymers of the invention find their application in the field of adhesives and the field of thermoplastic compositions.
• the invention also relates to a composition
• a composition comprising at least 1% by weight, relative to the total weight of the composition, of a copolymer as defined above.
• the composition may be an adhesive composition.
• the copolymer is present, advantageously, in a content of at least
• the adhesive composition may include additives such as tackifying resins, plasticizers, such as oils, in which case it will be a hot melt pressure sensitive adhesive composition (known by the abbreviation HMPSA).
• HMPSA hot melt pressure sensitive adhesive composition
• the glass transition temperature of an HMPSA composition will be controlled by the glass transition temperatures of the soft phase of the copolymer (i.e., in our case, the phase having a Tg less than 15 0 C), resin and oil (fulfilling the function of plasticizer) and their respective mass fractions in the soft phase according to a law of the type:
• w is the fraction by weight of the Tg block less than 15 0 C of the copolymer
• the soft fraction is the fraction by weight of resin incorporated in the low Tg phase (less than 20 ° C.).
• the soft oil is the fraction by weight of oil incorporated in the low Tg phase (less than 20 ° C.).
• Tg res is the glass transition temperature of the resin measured at the stress frequency of 1 Hz
• Tg oil is the glass transition temperature of the oil measured at the stress rate of 1 hz on the pure model copolymer
• Soft Tg is the glass transition temperature of the low Tg block (i.e. less than 15 0 C, in our case) of the type measured at the stress frequency of 1 Hz on the pure model copolymer.
• the composition In order for the composition to have adhesive properties at room temperature, it will be particularly important that the glass transition temperature be below room temperature.
• SAFT SAFT measures the ability of a hot melt adhesive to withstand a static force of 500 g (or 100 g) in shear (or peel) under a steady temperature rise of 0.4 ° C / min. It is therefore clear to one skilled in the art that the SAFT of a given composition will be related to its ability to maintain its modulus level, at low deformation rate as encountered in creep, over the temperature range. bigger.
• oils to be used as plasticizers in HPSA compositions are trimellitate type oils, such as trioctyl trimellitate, or even predominantly naphthenic oils such as Catenex N956 from Shell. It is disadvised to use oils of paraffinic type (typically Primol 352 oil, Exxon-Mobil), liquid polybutene type (typically Napvis 10) because, under certain conditions, they are incompatible with the copolymer and exude from the mixture.
• paraffinic type typically Primol 352 oil, Exxon-Mobil
• liquid polybutene type typically Napvis
• the tackifying resins are generally resins based on collophanes such as Forai AX, rosin ester such as Forai F85, resins known under the name pure monomer such as Krystallex F85, polyterpenes such as DERCOLYTE A 115 from DRT, hydroxylated polyesters (typically Reagem 5110 from DRT), terpene styrene (typically DERCOLYTE TS 105 from DRT), terpene pentaerythritol (typically DERTOLINE P2L), terpene phenol-based resins (typically Dertophene). T105 from DRT).
• the composition of the invention can be used as an adhesive, to constitute, for example, strips, labels and adhesive tapes, in various fields, such as hygiene, wood, binding, packaging.
• the invention also relates to the use of a copolymer as defined above as a hot melt adhesive.
• compositions of the invention may also be thermoplastic compositions.
• such compositions may further comprise one or more thermoplastic polymers, such as polymethyl methacrylate, polystyrene and polyvinyl chloride.
• This control of the level of the module can be done without increasing the glass transition temperature of the elastomer domains, which will make it possible to retain the impact-enhancing contribution provided by these domains.
• the use of the present invention will advantageously increase the temperature stability of the thermoplastic phase of the copolymer. This will lead to improved properties when the product is used in applications that expose it to high temperatures, such as in the field of luminaires.
• parts may be injected, molded, rolled, extruded thermoformed which will have excellent mechanical and thermal resistance during their application (glazing, Fresnel lens for projector, composition for uses near a heat source such as a automotive engine).
• compositions or thermoplastic compositions they generally comprise a mineral or organic base as defined above, so as to neutralize all or part of the CO 2 H acid functional groups, with a view to modulating the physical properties. of said composition.
• the compositions comprising copolymers according to the invention neutralized in whole or in part may be prepared by liquid, in which case the process comprises a step of contacting the copolymer with a mineral or organic base in a liquid medium, or by melting, in which case the process comprises a step of melting the copolymer with a mineral or organic base.
• FIGS 1 to 15 illustrate, in graphic form, the effect of the neutralization of copolymers of the invention on the physical properties thereof.
• DMTA (or DMA) is a method of analysis that measures the viscoelastic properties (G ', G'', tan d, eta *, ...) of a product as a function of temperature. at the given bias frequency, of 1 Hz in our examples.
• G ', G'', tan d and eta * respectively correspond to the elastic modulus, the loss modulus (in Pa), the ratio (G''/G') and the viscosity (in Pa / s).
• the capillary rheology measurements are carried out on a ROSAND RH7 double sheath rheometer by applying the Bagley and Rabinowitch corrections known to those skilled in the art. These measurements made on a product in the molten state make it possible to characterize the behavior of a product at a given temperature at high shear gradients, such as those usually encountered during the use of plastics or adhesive formulations. .
• the dynamic viscoelasticity measurements are carried out on an ARES viscoelasticimeter of
• the tensile measurements are carried out at ambient temperature at a traverse speed of 50 mm / min on an ADAMEL LHOMARGY DY 30 machine according to ISO 527-2.
• Cutting of the specimens is done using a charly robot driven milling machine on the model of 5A specimens. A minimum of 5 tests is performed for each product.
• n-butyl acrylate 3.47 g of a solution of 1,6-di [2- (N-tert-butyl-N- (1-diethylphosphono-2,2-dimethylpropyl) -N-oxyl) propionate] hexylene alkoxyamine, noted " DIAMS "of following formula:
• reaction medium is then brought to 114 ° C., and this temperature is maintained for 6 hours until a conversion of n-butyl acrylate is obtained.
• the molecular weights of n-butyl polyacrylate in SEC-equivalent polystyrene equivalents are 90 140 g / mole for the mass at the peak of the distribution (Mp), 57 730 for the number average molecular weight (Mn), 89 650 for the weight average molecular weight (Mw) and a polymolecularity index of 1.6.
• Mp mass at the peak of the distribution
• Mn number average molecular weight
• Mw weight average molecular weight
• a polymolecularity index of 1.6 a polymolecularity index of 1.6.
• 133 g of toluene, 35 g of styrene (S) and 6 g of methacrylic acid (AMA) are introduced into the reactor.
• the poly (styrene-co-methacrylic acid) b-poly (n-butyl acrylate) -b-poly (styrene-co-methacrylic acid) copolymer is recovered in the form of granules.
• the chemical composition of the copolymer obtained, expressed as a percentage by mass, is the following: PAbu / P (S, AMA): 70/30 (86.14).
• the molecular weights of the copolymer in polymethyl methacrylate equivalent determined by SEC are 372,280 g / mole for the weight average molecular weight (Mw).
• Characteristics of PRC302 P (S / AMA) -PABu-P (S / AMA): Mw 372,000 g.mol-1, IP 6.7, Composition: (12.5% S - 2% AMA) - 71% Abu - (12.5 % S - 2% AMA)
• a 20 L reactor equipped with a variable speed stirring motor, inputs for the introduction of reagents, taps for the introduction of inert gases for the removal of oxygen, such as nitrogen, and measurement probes (eg, temperature), a double jacket for heating / cooling the contents of the reactor through the circulation therein, a heat transfer fluid, Introduced 11 kg of n-butyl acrylate, 154 g of 1,6-di [2- (N-tert-butyl-N- (1-diethylphosphono-2,2-dimethylpropyl) -N-oxyl) alkoxyamine.
• the molecular weights of n-butyl polyacrylate in SEC-equivalent polystyrene were 52,726 g / mole for the mass at the peak of the distribution (Mp), 46,100 for the number average molecular weight (Mn), 109 000 for the weight average molecular weight (Mw) and a polymolecularity index of 2.4.
• Mp mass at the peak of the distribution
• Mn number average molecular weight
• Mw weight average molecular weight
• a polymolecularity index of 2.4 5 kg of toluene toluene solution of previously prepared n-butyl polyacrylate, 4 kg of toluene, 8.01 kg of methyl methacrylate and 0.9 kg of methacrylic acid are introduced into the reactor.
• the temperature was adjusted to 100 0 C for hour 30 minutes, then at 12O 0 C for lh30.
• the copolymer P (MMA / AMA) -PABu-P (MMA / AMA) is recovered in the form of granules.
• the chemical composition of the copolymer obtained, expressed as a percentage by weight, is as follows: PAbu / P (MMA, AMA): 35/65 (90,10).
• the molecular weights of the polymethyl methacrylate equivalent copolymer determined by SEC are 123 100 g / mol for the mass at the peak of the distribution (Mp), 75 620 for the number average molecular weight (Mn), 153 300 for the weight average molecular weight (Mw) and a polymolecularity index of 2.0.
• a heat transfer fluid is introduced 11 kg of n-butyl acrylate 154 g of 1,6-di [2- (N-tert-butyl-N- (1-diethylphosphono-2,2-dimethylpropyl) -N-oxyl) propionate] hexylene alkoxyamine labeled "DIAMS” (ARKEMA) and 10 8 g of N-tert-1-diethyl phosphono-2, 2-dimethylpropyl nitroxide noted “SGl” (ARKEMA).
• the reaction medium is then brought to 117 ° C., and this temperature maintained for 6 hours until reaching an n-butyl acrylate conversion of the order of 60%.
• the residual monomer is then removed at 75 ° C. under 200-300 mbar.
• the n-butyl polyacrylate is then diluted in 5.9 kg of toluene, and the toluene solution is drained from the reactor.
• the molecular weights of n-butyl polyacrylate in SEC-equivalent polystyrene were 52,726 g / mole for the mass at the peak of the distribution (Mp), 46,100 for the number average molecular weight (Mn), 109 000 for the weight average molecular weight (Mw) and a polymolecularity index of 2.4.
• Methyl polymethacrylate determined by SEC are examples of Methyl polymethacrylate determined by SEC.
• This example illustrates the effect of the solvent neutralization of the PRC 302 copolymer on the level of the elastic shear modulus G '.
• the PRC copolymer 302 is dissolved in a solvent, for example THF, by adding a dilute solution of KOH in water so as to introduce an equivalent of OH- per acid functional equivalent of PRC302 (for example, to neutralize the presence of equivalent to 30 g of a copolymer containing 5% AMA, 0.97 g of KOH dissolved in approximately 5 g of water must be introduced).
• a solvent for example THF
• KOH- per acid functional equivalent of PRC302 for example, to neutralize the presence of equivalent to 30 g of a copolymer containing 5% AMA, 0.97 g of KOH dissolved in approximately 5 g of water must be introduced.
• the mixture is stirred at ambient temperature for a few hours and then the solvents are evaporated first at 60 ° C. and then when the bulk of the solvent is removed by placing the product in a vacuum oven at 120 ° C. for 1 hour.
• a sample of PRC302 is prepared equivalently without the introduction of base to neutralize the product.
• FIG. 1 represents the evolution of the elastic shear modulus G '(Pa) as a function of time ( 0 C) and also the evolution of tan d as a function of time.
• Table 1 below shows the increase of the elastic shear modulus on the neutralized PRC 302 in comparison with the unneutralized product.
• This example illustrates the effect of the solvent neutralization of the PRC 302 copolymer on the viscosity, the elastic shear modulus G ', the Young's modulus, and the low shear rate viscosification.
• the PRC 302 copolymer is hot kneaded in Branbaender at the temperature of 18O 0 C for one hour with or without the introduction of KOH, the pellets were ground in powder form.
• Figure 2 compares the evolution of the mixing torque for the product with KOH and for the control. Table 2 contains the various information on the mixtures used.
• V corresponds to the speed of rotation of the rotors in the mixer and Tmax corresponds to the self-heating temperature caused by the shear phenomenon
• Figure 4 shows the tensile curve at 50 mm / min of the neutralized product compared to the unneutralized product. Table 4 shows the following results
• 2-amino-2-methylpropanol which is a high-boiling point liquid (160 ° C.) in place of KOH which is a high-melting solid.
• KOH a high-melting solid
• Table 5 contains information on the various mixtures made.
• Figure 7 shows the comparative DMAs of the different products and Table 6 illustrates the module increases.
• Table 8 describes the melt blends made with these two copolymers.
• FIGS. 9 and 10 show the effect of the neutralization on the mixtures with DC 59.
• FIG. 9 shows the mixing torques as a function of time
• FIG. 10 shows the evolution of the material temperature as a function of time.
• Figure 11 and Table 9 illustrate on PIL 0407 in comparison with the unmixed product the effect of the neutralization on the increase of the mechanical properties of the copolymer.
• the neutralized copolymer not only has a double modulus at room temperature without having modified the Tg of the soft phase, which for a given HMPSA formulation would make it possible to obtain a product with a double modulus with respect to the same copolymer formulated without neutralization. But, this copolymer after neutralization also has a much better thermal stability as shown by its elastic modulus which varies very little with the temperature compared to the unneutralized product. This last is also found on the evolution of tan delta as a function of temperature: after neutralization, PiI 0407 shows a more elastic and less viscous behavior (tan delta level lower). All of these elements should lead to HMPSA formulations whose temperature resistance (or SAFT) will be improved over the unneutralized product.
• the neutralization at 18O 0 C seems more efficient than at 180 ° C. (torque level during mixing in Table 8, module level in Table 9, tan d lower in the graph 11): the neutralization temperature may serve as another parameter in order to adapt the thermomechanical properties of a given product.
• the formulator By being able to achieve the neutralization during the mixing of the various components forming a pressure-sensitive hot melt, the formulator will be free to adapt the properties of its mixture to its application while having to deal with only one raw material .
• the properties of a control mixture are compared with those of the same mixture neutralized with 1 equivalent of KOH or with 1 equivalent of 2-amino-2-methylpropanol.
• Figure 12 compares the mixture pairs in the Brabaender for the control product and HMPSA neutralized with 2-amino-2-methylpropanol.
• thermo ⁇ mechanical properties of the control formulation and of the formulation neutralized with 2-amino-2-methyl propanol or KOH in DMA were evaluated. The measurements are shown in Figure 15.
• the neutralization allows a module increase of the formulation whose amplitude can be controlled according to the base used. This increase is sensitive not only at ambient temperature but also at high temperatures, which makes it possible to improve the SAFT properties of a given formulation. This increase is obtained without increasing the Tg of the soft phase.
• the neutralization will allow us to reduce the amount of polymer to obtain a formulation of a given module, and thus reduce the overall cost of the product.
• care must be taken to control the level of neutralization of the product: thus, in our example, we have made products that are quite tacky and very cohesive with a large proportion of polymer whose cohesion we have further strengthened by neutralization.

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