Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • 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
  • 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
  • C08F293/005—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 using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent
• • 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
  • C08F297/00—Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer
• • 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
  • C08F2438/00—Living radical polymerisation
  • C08F2438/02—Stable Free Radical Polymerisation [SFRP]; Nitroxide Mediated Polymerisation [NMP] for, e.g. using 2,2,6,6-tetramethylpiperidine-1-oxyl [TEMPO]
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2353/00—Characterised by the use of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers

Definitions

• the present invention relates to the field of acrylic materials, particularly to acrylic materials intended to coat certain thermoplastic materials and more particularly to the field of acrylic monolayer films.
• Acrylic resins are increasingly used thermoplastic polymers because of their exceptional optical properties and their ease of shaping. Mention may in particular be made of their shiny appearance, their very high degree of transparency with at least 90% of light transmission, their hardness, their ability to thermoform, their resistance to aging, in particular to atmospheric agents (more particularly to UV rays). For these technical and aesthetic reasons, it is important to find transparent and ductile acrylic films to protect plastic parts whose resistance to aging is limited. Indeed, if such films, by their acrylic nature, resist UV well (durability) and allow to bring to the room on which they are deposited this same property, they risk by the fragile nature of methacrylic materials to weaken the of the coated part.
• ABS acrylonitrile butadiene styrene copolymer
• PVC polyvinyl chloride
• PC polycarbonate
• PP polypropylene
• PS polystyrene
• an acrylic film preferably kept in the form of a roll, is, in a 1 st step (optionally preceded by continuous hot bonding with another film or thermoplastic substrate in a step called co-laminating), preformed to the geometry required, so as to match the internal surface of the mold intended to form the desired object.
• a 2nd step the thermoplastic resin melt is injected into the mold and brought into contact with the film, which has the effect of the adhering surface of the thus formed object.
• a particularly preferred embodiment of this technique comprises the simultaneous implementation of the 2 steps previously described, by means of an appropriate apparatus.
• This embodiment is referred to as molding with simultaneous film insertion (FI M).
• the acrylic films used in this technique can be used as they are, in other words while retaining their transparency. They can also be colored, while retaining their shiny appearance. Finally, they can receive by a particular printing process a drawing, a pattern, an image or even characters, text or a logo capable of transmitting certain information to the consumer. As an example of printing, we can cite that of a drawing imitating the appearance of wood.
• the designs or patterns printed on the transparent acrylic film can therefore be applied to the surface of the object in thermoplastic resin, in particular by FIM. The film thus printed improves the aging of the object thus coated.
• bearing the pattern or design printed on that of its 2 surfaces which is in contact with the substrate it also protects the pattern from contact with atmospheric agents, and adds to the design a particularly sought-after visual effect of relief.
• the first consists in mixing with an acrylic resin, sufficient impact modifier of the bark-heart type (Rohm WO 99 29766 and US 6 420 033 B1, Sumitomo EP 1000 978 A1, Mitsubishi Rayon EP 0 763 560 A1) to make it ductile.
• US Patent 6,147,162 describes a monolayer acrylic film made from a composition comprising 50 to 95% of a specific acrylic resin, and 5 to 50% of a multi-layer acrylic polymer, containing an elastomer layer. Said polymer (also known to a person skilled in the art under the name of impact modifier) is dispersed in the resin acrylic. This film is suitable for the FIM technique, and provides good surface hardness to the object thus coated.
• EP 1000 978 A1 also describes an acrylic film made from a composition comprising 50 to 95% of a specific acrylic resin, and 5 to 50% of an impact modifier, suitable for coating by using the FIM technique. , and having improved surface hardness.
• This document also mentions a laminated film (that is to say a multilayer film), and more precisely a bilayer film, the inner layer of which consists of the composition described above, and the outer layer of an acrylic resin without modifying shock.
• This bilayer film presented as having excellent surface hardness, can also be wound up in the form of a roll.
• US Pat. No. 6,444,298 B1 describes a laminated acrylic film (or even a multilayer film) comprising a layer containing an acrylic resin and particles of acrylic elastomer (corresponding to an impact modifier), called flexible layer, and a layer containing an acrylic resin without modifying shock, known as the surface layer.
• a three layer system is also disclosed, in which 2 surface layers are separately bonded to the 2 surfaces of the flexible layer.
• Such a multilayer film makes it possible to improve the coloring treatment, by avoiding bleaching and weakening of the coloring of the resin linked to the presence of impact modifiers.
• This patent recommends ensuring that the ratio of the thickness of the flexible layer to the total thickness of the film is between 50 and 100%, preferably between 60 and 100%.
• This method which consists in mixing with an acrylic resin, sufficient impact modifier of the core shell type finds its limits in the fact that the size of the core shell particles being greater than or equal to 50 nm, the transparency of the material is only ensured by the adequacy of the refractive indices of the particles and of the acrylic resin. This adequacy is only valid in a given temperature range and outside this temperature, the material whitens.
• the second method also attempts to solve the problem of transparency: it consists in using block copolymers of type (A) nB or A is a block compatible with PMMA and B is a block of low temperature glass transition acrylate . Such products are reputed to be organized on a nanometric scale in the acrylate and methacrylate domains. The fineness of these areas ensures good transparency of the materials at visible wavelengths whatever the temperature.
• the Kaneka company Patent Application JP2000-397401 claims materials containing at most 95% of block copolymers to be used as films. Even if it demonstrates the interest of block copolymers, this invention is of limited industrial interest because it requires the mixing of block copolymers and homopolymer PMMA in addition to the manufacture of these materials. In addition, this invention uses a catalysis with copper complexes to synthesize these block copolymers, which is unacceptable for applications where the level of transparency of the resins must be the best possible because the copper complexes are very colored molecules. On the other hand, for the block copolymers described in this invention to be useful in the manufacture of acrylic film, they must be mixed with core-shell additives at a content of between 5 and 95%.
• copolymers of the invention are obtained by controlled radical polymerization in the presence of nitroxides as described below.
• the present invention describes the chemical compositions of block copolymers necessary for producing acrylic films having a modulus between 300 MPa and 1800 Mpa and a high transparency.
• chemical composition the applicant intends to specify the nature of the monomers involved in the formation of each block, the ratio of these monomers, the average molecular weights in number and by weight and the rate of copolymers in the final material.
• the present invention therefore aims to obtain an acrylic film which, while maintaining its qualities of transparency, simultaneously has a very high elongation at break (allowing it in particular to resist passage through printing devices), combined with an elastic module offering the very good flexibility necessary for the storage of the roll film.
• the film of the invention is a film obtained by the techniques of transformation of thermoplastic materials such as extrusion, from a composition comprising: from 95 to 100% by weight of at least one block copolymer corresponding to the formula (A) m - (B) n -l and from 0 to 5% by weight of at least one polymer whose composition corresponds to block A of the copolymer, n being an integer greater than or equal to 2, m being an integer less than or equal to n, B a polymer block linked directly to the core I by a covalent bond, obtained by the polymerization of a mixture of monomers (B 0 ) containing at least 60% by weight of acrylic monomers (bi), A being a polymer block, directly linked to block B by a covalent bond, obtained by the polymerization of a mixture of monomers (A 0 ) containing at least 60% by weight of methacrylic monomers (ai).
• the core (I) is an organic grouping having n (greater than or equal to 2) carbon atoms to which the blocks B are attached by one of the valences of these carbon atoms.
• I corresponds to one of the general formulas la, Ib and the following:
• Z is a polyfunctional organic or inorganic radical with molar mass greater than or equal to 14.
• Z is associated with n acryl type functions in formula la, n methacryl type functions in formula Ib and n styryl type functions in.
• Z can be a polyalkoxy group, in particular dialkoxy, such as the 1, 2 ethane-dioxy, 1, 3 propane-dioxy, 1, 4 butane radicals.
• Z can also be an inorganic group, for example an organo-metallic complex such as: M ⁇ + , O " n , the second valence of the oxygen atoms corresponds to the bond appearing between Z and the acryl, methacryl and styryl groups.
• M can be an atom of magnesium, calcium, aluminum, titanium, zirconium, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, palladium, platinum, copper, silver, gold, zinc tin.
• B is a polymer block linked directly to the core I by a covalent bond, obtained by the polymerization of a mixture of monomers (B 0 ) containing at least 60% by weight of acrylic monomers (bi). It has a glass transition temperature (Tg) of less than 0 ° C, a weight average mass (Mw) of between 40,000 and 200,000g / mol and a polydispersity index (Ip) of between 1, 1 and 2.5 and of preferably between 1, 1 and 2.0.
• Tg glass transition temperature
• Mw weight average mass
• Ip polydispersity index
• the mixture of monomers Bo comprises - from 60 to 100% by weight of at least one acrylic monomer (bi) chosen from alkyl acrylates having an alkyl chain comprising at least two carbon atoms and preferably at at least four carbon atoms such as butyl, octyl, nonyl, 2-ethylhexyl acrylate, polyethylene glygol acrylates or acrylonitrile.
• the other monomers, (b 2 ) forming part of the block B are chosen from monomers which can be polymerized by the radical route, such as ethylenic, vinyl and similar monomers.
• Block A must have a good affinity with the materials to be covered with the film.
• Block A according to the invention has a Tg greater than 50 ° C. It is obtained by the polymerization of a mixture of monomers A 0 comprising:
• methacrylic monomer (ai) chosen from alkyl methacrylates such as methyl, butyl, octyl, nonyl, 2- (ethyl hexyl), or alternatively functional methacrylics such as methacrylic acid, glycidyl methacrylate, methacrylonitrile or any methacrylate comprising an alcohol, amide or amino function,
• mixture A can contain a proportion of the monomers used for block B. This is at most equal to 20% of the mixture of monomers used for block A.
• the weight average molecular weight (Mw) of the block copolymer (A) m - (B) nl is between 80,000 g / mol and 300,000 g / mol with a polydispersity between 1, 5 and 2.5.
• the copolymer (A) m - (B) n -i contains between 60% and 10% by weight of monomers (B 0 ) and preferably between 50 and 25%.
• the proportion of block B in the block copolymer is between 10 and 50%, preferably between 20 and 50%.
• the process for preparing the copolymers (A) m - (B) n -l therefore consists in initiating the polymerization of the monomer (s) (B 0 ) necessary for the block B by an initiator of the alkoxyamine type.
• the choice of initiators of the invention is essential for the successful manufacture of the material: these initiators make it possible to control the number of arms of the block copolymer as well as its good sequencing. This last characteristic depends on the choice of the nitroxide control agent produced by the decomposition of the initiating alkoxyamines.
• the general formulas of the alkoxyamine initiators chosen according to the invention are therefore the following:
• Ha llb Ile in which: Z has the same meaning as above, the carbon atom in the alpha position of the NO bond carries at least one organic group RL of molecular mass greater than or equal to 16 g / mol.
• the other valences of nitrogen or of carbon in the alpha position carry organic groups such as linear or branched alkyl groups such as ter butyl or isopropyl, optionally substituted such as 1, 1 dimethyl, 2-hydroxy ethyl , hydrogen atoms, aromatic rings such as the optionally substituted phenyl group.
• the preferred alkoxyamines of the invention are those corresponding to the following formulas:
• R as well as the groups attached to the nitrogen atom and to the carbon atom in alpha of nitrogen have the same meaning as before.
• n integer greater than or equal to 2 makes it possible in particular to ensure a very high rate of block copolymers in the final material by limiting the presence of unreacted block B after the formation of A.
• RL is particularly important so as to ensure, during the formation of B, good control of the polymerization which makes it possible to maintain a significant reactivity of B during the reboot of A.
• X1 and X2 the following two nitroxides X1 and X2 will be cited:
• the manufacturing process therefore consists in first polymerizing the block B in the presence of an initiator of formula II and optionally an additional quantity of compound X at a temperature between 60 ° C and 150 ° C, under a pressure ranging from 1 to 10 bar.
• the polymerization can be carried out in the presence or not of a solvent or in a dispersed medium.
• the polymerization is stopped before 90% conversion.
• the quantity of monomer is then added for block A.
• the polymerization of block A is carried out under conditions similar to that of block B.
• the polymerization of block A is continued at the targeted conversion.
• the recovery of the product is done simply by drying the polymer according to a means known to those skilled in the art. During this step, the various additives necessary for the UV and thermal protection required for the application of acrylic film are added and by extrusion with a flat die, a film is produced with the desired thickness.
• the material obtained contains at least 95% of block copolymers.
• an amount of homopolymer A can be added so that the level of copolymer present in the material is between 95 and 100%. This addition may prove to be necessary during the formation of block A because the conversion of the last traces of monomers can lead those skilled in the art to add a new initiator capable of converting these residual monomers. Within these limits, the properties of the material conform to use in acrylic film.
• the film of the invention also contains all the additives necessary for its use and for its coloring, such as organic or mineral pigments.
• the film of the invention can be obtained by well-known extrusion techniques such as calendering, blowing and casting.
• the film of the invention is in the form of a thin layer with a thickness between 50 and 200 microns and preferably between 70 and 90 microns.
• the films produced according to the invention have domains of an elastomeric nature of size less than 50 nm, an elastic modulus between 300 and 1800 MPa, an elongation at break greater than 60% and a Trouble less than 2.
• the film of the invention can be used as a surface treatment for the protection of materials such as ABS, PVC, PS, PP or PC.
• protection techniques that may be mentioned by way of non-limiting example, decoration in the mold, decoration by lamination, screen coating and as a paint substitute.
• the invention also relates to the parts treated as described above as well as the use of these parts in various applications, in particular those requiring, inter alia, good stability in a wide temperature range.
• the film of the invention has good transparency (cloudiness less than 2) which remains practically constant whatever the temperature of use chosen between -40 and 100 ° C.
• MAM Methyl methacrylate
• AMA Methacrylic acid
• Ip polymolecularity index or polydispersity index
• the characterizations of the materials are made according to standard methods of analysis.
• the molecular weights are determined using steric exclusion chromatography and are expressed in polystyrene equivalents.
• thermoplastic screw through a flat die.
• the films then pass through a thermoregulated calender with 3 rolls and are then cooled in a water bath.
• the samples are steamed under vacuum at 80 ° C for
• the screw is purged 1 hopper before sampling or disassembled and cleaned.
• the films thus obtained were evaluated mechanically and optically according to the respective standards:
• ASTM D1003 standard determination of total light transmission and cloudiness (Trouble) Analysis by atomic force microscope (Digital Instrument)
• Tg (which appear dark on the pictures) is much less than 50 nm.
• 6000 g of n-butyl acrylate, 65 g of initiator 111 are introduced into a metal reactor provided with mechanical stirring and a double jacket. (corresponding to the formula below) and 3.2 g of excess nitroxide X1 (i.e. an II1 / X1 molar ratio of 7%). The temperature of the reaction medium is brought to 115 ° C.
• a sample makes it possible to determine the characteristics of block B thus produced by steric exclusion chromatography.
• composition analysis by 1 H NMR indicates:
• the product obtained is placed in an oven under a nitrogen atmosphere at 200 ° C for 1 hour.
• the polymer turns black and cannot be extruded without degradation to form a film.
• This product is sticky and cannot be extruded to form a film.
• This example illustrates the importance of the choice of the amount of acrylate contained in the block copolymer and the fact that all the copolymers claimed in WO 97/27233 cannot be used in a monolayer film.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Inorganic Chemistry (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Graft Or Block Polymers (AREA)
• Laminated Bodies (AREA)

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• 2003
  • 2003-09-24 FR FR0311174A patent/FR2852961B1/fr not_active Expired - Fee Related
• 2004
  • 2004-03-23 JP JP2006505747A patent/JP2006521441A/ja active Pending
  • 2004-03-23 EP EP04742323A patent/EP1611190A1/fr not_active Withdrawn
  • 2004-03-23 MX MXPA05010169A patent/MXPA05010169A/es unknown
  • 2004-03-23 CA CA2520164A patent/CA2520164C/en not_active Expired - Fee Related
  • 2004-03-23 WO PCT/FR2004/000713 patent/WO2004087796A1/fr not_active Ceased
  • 2004-03-23 KR KR1020057018110A patent/KR20050114699A/ko not_active Ceased
  • 2004-03-23 AU AU2004226194A patent/AU2004226194B2/en not_active Ceased
  • 2004-03-23 US US10/550,808 patent/US20080050572A1/en not_active Abandoned

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