Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G71/00—Macromolecular compounds obtained by reactions forming a ureide or urethane link, otherwise, than from isocyanate radicals in the main chain of the macromolecule
  • C08G71/04—Polyurethanes
• • 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
  • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
  • C08J9/02—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by the reacting monomers or modifying agents during the preparation or modification of macromolecules
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2110/00—Foam properties
  • C08G2110/0041—Foam properties having specified density
  • C08G2110/0066—≥ 150kg/m3
• • 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
  • C08J2205/00—Foams characterised by their properties
  • C08J2205/04—Foams characterised by their properties characterised by the foam pores
• • 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
  • C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
  • C08J2375/04—Polyurethanes

Definitions

• the invention relates to a process for preparing a polyurethane foam by (i) the reaction of at least one polyoxamic acid with at least one polyol, in the presence of an oxidant, followed by (ii) foaming polyurethane obtained in step (i) using carbon dioxide.
• the invention also relates to a polyurethane foam obtained using the process according to the invention.
• Polymer foams combine the intrinsic lightness of porous materials with low thermal and electrical conductivity, as well as good filtration and energy absorption capacities.
• the polymeric nature of these materials also gives them good mechanical resistance. Thanks to its particular properties, polymer foams are used in various fields, such as packaging, electronics, transport, furniture, textiles, aerospace, or construction materials for example.
• polymer foams are prepared by the nucleation of gas bubbles in a polymer or mixture of monomers, followed by a phase change stabilizing the resulting porous structure (vitrification in the case of a thermoplastic polymer , gelation in the case of a thermosetting polymer).
• the gas bubbles can be generated by a foaming agent, which can be either “physical” (foaming agent released during a phase change), or “chemical” (foaming agent released following a chemical reaction, and notably thermal decomposition).
• polyurethane foams are the most produced polymer foams in the world, in particular because of their well-known and controlled preparation process, and access to a wide range of polyurethanes with physical properties. -varied chemicals. Polyurethanes are usually prepared by the polyaddition of polyols to polyisocyanates, according to the reaction first described by Bayer.
• Carbon dioxide is a foaming agent which has the advantage of not being highly toxic or highly harmful to the environment, of not leaving any by-product in the foam, and of making it possible to obtain polyurethane foams with physicochemical properties meeting consumer demands. Consequently, it would be desirable to have a self-foaming system capable of releasing carbon dioxide in situ to foam polyurethanes.
• the Applicant has therefore sought a self-foaming process for preparing polyurethane foams which is not only satisfactory in terms of conversion rate and physicochemical properties of the foams obtained, but also less toxic and less harmful to the environment. environment than the process commonly used with (poly)isocyanates and polyols in the presence of water. More precisely, the Applicant sought a new route for synthesizing polyurethanes, a reagent of which makes it possible to generate poly isocyanate and carbon dioxide in situ as a foaming agent.
• oxamic acids are known to be stable and easily accessible by the addition of an amine to an oxalic acid derivative. Then, the oxidative decarboxylation of oxamic acid to isocyanate can be carried out either in the presence of a metal catalyst (Minisci et al., J.Chem. Soc, Chem. Commun, 1994, 679, Minisci et al., J. Org.
• the reaction generates few by-products, which can be easily eliminated under reduced pressure and/or by heating.
• the process according to the invention advantageously makes it possible to easily obtain polyurethane foams.
• the process is self-foaming.
• the process of a polyurethane foam according to the invention comprises the following steps: a) the reaction, in the presence of an oxidant and at a temperature ranging from 60 to 150 ° C, of at least a polyoxamic acid of formula (II): ol of formula (III): in which
• - L1 represents a saturated hydrocarbon group, linear or branched, cyclic or acyclic, in which one or more CH 2 have optionally been replaced by O and/or S; or an unsaturated hydrocarbon group, linear or branched, comprising at least one double bond and/or at least one aromatic ring optionally substituted by one or more alkyl and/or alkoxy groups; or a saturated hydrocarbon group, linear or branched, cyclic or acyclic, comprising one or more COOH or polyethylene glycol substituents; or a triester of fatty acids of which one or more CH 2 have optionally been replaced by O and/or S,
• - L2 represents a saturated hydrocarbon group, linear or branched, cyclic or acyclic, in which one or more CH 2 have optionally been replaced by O; or an unsaturated hydrocarbon group, linear or branched, in which one or more CH 2 have optionally been replaced by O and comprising at least one aromatic ring optionally substituted by one or more alkyl and/or alkoxy groups or at least one aromatic heterocycle; or a triester of fatty acids; or a di, tri or tetra polyester of polyalkylene glycol,
• step a carbon dioxide and at least one polyisocyanate are generated in situ.
• the oxidant used in step a) is advantageously a hypervalent iodized oxidant.
• the process according to the invention has the advantage of not using a highly toxic and/or environmentally harmful reagent since the polyisocyanate is generated in situ and is not isolated, and does not require the use of phosgene.
• the process according to the invention has the advantage of providing access to a wide range of polyurethane foams, of very varied chemical structure and therefore of varied physicochemical properties.
• polyoxamic acids are prepared from polyamines and oxalic acid derivatives. Their synthesis is easy, and provides access to a wide variety of polyoxamic acids thanks to the wide choice of accessible polyamines.
• the method according to the invention has the advantage of being reproducible and easy to implement since the operating conditions are simple.
• the method according to the invention also has one or other of the following characteristics, or a combination of these:
• step b) the carbon dioxide used for foaming in step b) is entirely generated in step a);
• R8 R9, RIO, Rll and R12 identical or different and independently representing H, (CH 2 )i, CH 3 , CH 3 -(CH 2 )i, O(CH 2 )i, CH 3 O or CH 3 -(CH 2 )iO,
• the at least one polyoxamic acid is such that x is equal to 2 or 3;
• the at least one polyoxamic acid is such that L1 is chosen from:
• the at least one polyoxamic acid is such that L1 is chosen from: (CH 2 ) (Ll-
• the at least one polyol is such that L2 is chosen from the following groups:
• R20, R21, R22, R23, R24 and R25 being identical or different and independently representing H, (CH 2 ) S , CH 3 or CH 3 -(CH 2 )s,
• R21 and R22 which can together represent a group CH(R22a)-CH(R22b)- CH(R22c)-CH(R22d) with R22a, R22b, R22c and R22d identical or different and independently representing H , (CH 2 ) S , CH 3 or CH 3 -(CH 2 ) S ,
• R32, R33, R34, R36, R36', R45, R47, R48 and R49 independently representing H, CH 3 or CH 3 (CH 2 ) r ,
• R37, R38, R39, R40, R41, R42, R43 and R44 being identical or different and independently representing H, (CH 2 ) S , CH 3 , CH 3 -(CH 2 ) S , O(CH 2 ) S , CH 3 O OR CH 3 -(CH 2 ) S O,
• - B representing a hydrocarbon chain, linear or branched, comprising 12 to 30 carbon atoms, and comprising at least one double bond
• the at least one polyol is such that y is equal to 3 or 4;
• the at least one polyol is such that L2 is chosen from:
• the at least one polyol is such that L2 represents:
• the oxidant is a hypervalent iodine compound, preferably chosen from bis(trifluoroacetoxy)iodobenzene, bis(acetoxy)iodobenzene, poly[4-(diacetoxyiodo)styrene], hydroxybenziodoxole, and acetoxybenziodoxole;
• step c subsequent to step b), of purifying the polyurethane foam (I), preferably by heating and/or under reduced pressure;
• the surfactant (IV) is chosen from:
• the polyurethane foam (I) is purified by a heating step and/or under reduced pressure.
• the invention also relates to a polyurethane foam obtained using the process according to the invention.
• this polyurethane foam has physicochemical properties of the same order of magnitude and comparable to those obtained by the process using poly isocyanates, polyols and water.
• polyurethane foams according to the invention also have one or other of the following characteristics, or a combination of these:
• the density of the polyurethane foam (I) ranges from 10 to 1000 kg.m 3 , preferably from 100 to 300 kg.m 3 ;
• the polyurethane foam has cells whose diameter is between 0.1 mm and 2 mm, preferably between 0.2 mm and 1.5 mm, the diameter being measured using a scanning electron microscope at 50 Pa and 7.00 kV on sections transverse to the direction of expansion of the material.
• Figure 1 is a photograph of PU2 foam.
• Figure 2 is an image of PU2 foam observed under a scanning electron microscope (FEI QUANTA, 7 kV).
• the invention relates to a self-foaming process for preparing polyurethane foams (I).
• the method according to the invention comprises the following steps:
• step b) foaming of the polyurethane (I) obtained in step a) in the presence of carbon dioxide.
• Polyurethane (I) is advantageously thermosetting.
• the reaction temperature in step a) ranges from 80°C to 130°C.
• the reaction is carried out at atmospheric pressure.
• x and y are both greater than or equal to two, and at least one of x or y is greater than or equal to 3.
• the polyurethane (I) is crosslinked .
• Polyurethane (I) is prepared from one or more polyoxamic acids (II). According to a particular embodiment, the polyurethane foam (I) is prepared from a single polyoxamic acid (II).
• alkylene group is meant a divalent alkyl group. Unless otherwise specified, an alkylene group can be branched or linear, cyclic or acyclic.
• R2 and R3 which can together represent a group CH(R7a)-CH(R7b)-CH(R7c)- CH(R7d) with R7a, R7b, R7c and R7d identical or different and independently representing H , (CH 2 )i, CH 3 , CH 3 -(CH 2 )i, CH 3 O or CH 3 -(CH 2 )iO,
• R8 R9, RIO, Rll and R12 identical or different and independently representing H, (CH 2 )i, CH 3 , CH 3 -(CH 2 )i, O(CH 2 )i, CH 3 O or CH 3 -(CH 2 )iO,
• Rll and R12 which can together represent a group O-CH(R7a)-CH(R7b)- CH(R7c)-(CH(R7d))j, it being understood that at least two groups among R7a, R7b, R7c, R7d , R8, R9, RIO, Rll and R12 represent (CH 2 )i or O(CH 2 )i,
• R13, R14, R15, R16, R13', R14', R15' and R16' identical or different and independently representing H, CH 3 (CH 2 ) k or CH 3 (CH 2 ) k O,
• - A representing a hydrocarbon chain, linear or branched, comprising 12 to 30 carbon atoms, and of which one or more CH 2 have been replaced by S,
• the at least one polyoxamic acid (II) is such that L1 represents Ll-1 or Ll-l'with m, m' and m" being identical or different and representing independently of one another an integer preferably ranging from 1 to 20, preferably from 1 to 14, and preferably from 6 to 10.
• x is preferably equal to 2 or 3, and advantageously is equal to 2 when L1 represents Ll-1 or equal to 3 when L1 represents Ll-1'.
• the at least one polyoxamic acid (II) is such that L1 represents Ll-2.
• Ll-2 is such that RI represents (CH 2 )i, CH 3 or CH 3 -(CH 2 )i, RI" and R3" represent H, CH 3 or CH 3 -(CH 2 )i, R2 represents H, (CH 2 )i, (CH 2 )iS, R3 represents H, (CH 2 )i, CH 3 or CH 3 -(CH 2 )i, R4 represents H, CH 3 , CH 3 -(CH 2 )i or (CH 2 )iCH(CH 3 )S, R5 represents H or (CH 2 )i and R6 represents H.
• polyoxamic acids (II ) the following polyoxamic acids can be cited:
• Ll-2 is such that RI, RI", R2, R3, R3", R4, R5 and R6 are identical or different and independently represent one of the other H, (CH 2 )i, CH 3 or CH 3 -(CH 2 )i.
• x is preferably equal to 2.
• poly oxamic acids (II) according to this embodiment, the following poly oxamic acids may be cited:
• Ll-2 is such that RI and R6 represent (CH 2 )i, R4 and R5 represent CH 3 or CH 3 -(CH 2 )i, and R2 and R3 together represent a group CH(R7a)-CH(R7b)-CH(R7c)-CH(R7d) with R7a, R7b, R7c and R7d identical or different and independently representing H, (CH 2 ) i CH 3 , CH 3 -(CH 2 )i, CH 3 O or CH 3 -(CH 2 )iO, and preferably H, (CH 2 )i, CH 3 , OR CH 3 -(CH 2 )i.
• poly oxamic acid (II) the following poly oxamic acid can be cited:
• the at least one polyoxamic acid (II) is such that L1 represents Ll-3.
• RI', R2', R3', R4', R5' and R6' are identical or different and preferably independently represent H, (CH 2 )i, CH 3 or CH 3 -(CH 2 )i.
• poly oxamic acid (II) according to this embodiment, the following poly oxamic acid can be cited:
• the at least one polyoxamic acid (II) is such that L1 represents Ll-4.
• j preferably represents 0.
• Rll and R12 together represent a group O-CH(R7a)-CH(R7b)-CH(R7c)-(CH(R7d)) j, with R7a, R7b, R7c and R7d as defined above and j representing 0 or 1.
• R8, R9 and RIO represent H.
• the at least one polyoxamic acid (II) is such that L1 represents Ll-5.
• i is advantageously an integer ranging from 1 to 10, preferably ranging from 1 to 6, and in particular equal to 4.
• the at least one polyoxamic acid (II) is such that L1 represents Ll-6.
• R13, R14, R15 and R16 are preferably identical or different and independently represent H or CH 3 -(CH 2 ) k .
• i is an integer preferably ranging from 1 to 10, and in particular from 1 to 4.
• poly oxamic acid (II) mention may be made of poly acid oxamic for which R13, R14, R15 and R16 each represent H and i is equal to 1.
• the at least one polyoxamic acid (II) is such that L1 represents Ll-7.
• R13, R14, R15, R16, R13', R14', RI 5' and R16' identical or different and preferably independently representing H, CH 3 O or CH 3 ( CH 2 )kO.
• R13, R13', R16 and R16' represent H.
• p preferably represents an integer ranging from 1 to 4.
• the at least one polyoxamic acid (II) is such that L1 represents Ll-8.
• R17 represents H or CH 3 (CH 2 ) k , with k preferably ranging from 0 to 4, and in particular from 0 to 2.
• polyoxamic acids (II) according to this mode of realization, we can cite the following polyoxamic acids: [0081][Chem. 22]
• the at least one polyoxamic acid (II) is such that L1 represents Ll-9.
• R17 represents H or CH 3 (CH 2 ) k with k being an integer preferably ranging from 0 to 4, more preferably from 0 to 2, and in particular being equal to 0.
• R18 preferably represents H or CH 3 (CH 2 ) kwith k ranging from 0 to 4, preferably from 0 to 2, and in particular being equal to 1, or R18 represents CH 2 [OCH 2 CHCH 3 ] m NHCOCOOH or CH 2 [OCH 2 CH 2 ] m OH.
• poly oxamic acids (II) the following poly oxamic acids may be cited:
• the at least one polyoxamic acid (II) is such that L1 represents Ll-10.
• R17 represents H or CH 3 (CH 2 ) k with k being an integer preferably ranging from 0 to 4, more preferably from 0 to 2, and in particular being equal to 0.
• R18 preferably represents H or CH 3 (CH 2 ) kwith k ranging from 0 to 4, preferably from 0 to 2, and in particular being equal to 1.
• R18' preferably represents H, CH 3 (CH 2 ) k , or CH 2 [OCH 2 CH 2 ] m OH.
• poly oxamic acid (II) the following poly oxamic acid can be cited:
• the at least one polyoxamic acid is such that L1 represents Ll-11.
• Ll-11 may represent a triester of fatty acids optionally functionalized with cysteamine.
• the fatty acids may in particular be a saturated fatty acid such as stearic acid, or an unsaturated fatty acid functionalized with cysteamine at the level of the double bond(s).
• unsaturated fatty acids we can mention in particular oleic acid, palmitoleic acid, erucic acid and linoleic acid.
• the polyurethane (I) is prepared from at least one polyol of formula (III). According to a particular embodiment, the polyurethane is prepared from a single polyol (III). According to another particular embodiment, the polyurethane (III) is prepared from two polyols (III).
• the polyol(s) (III) comprise at least two hydroxyl functions, preferably two, three, four, five or six, and in particular two, three or four or even three or four.
• y represents an integer greater than or equal to 2, preferably equal to 2, 3, 4, 5 or 6, and in particular 2, 3 or 4, or even 3 or 4.
• the polyol(s) is such that L2 represents a saturated hydrocarbon group, linear or branched, cyclic or acyclic, in which one or more CH 2 have optionally been replaced by O; or an unsaturated hydrocarbon group, linear or branched, in which one or more CH 2 have optionally been replaced by O and comprising at least one aromatic ring optionally substituted by one or more alkyl and/or alkoxy groups or at least one aromatic heterocycle; or a triester of fatty acids; or a di, tri or tetra polyalkylene glycol polyester.
• L2 is chosen from the following groups:
• R21 and R22 which can together represent a group CH(R22a)-CH(R22b)- CH(R22c)-CH(R22d) with R22a, R22b, R22c and R22d identical or different and independently representing H , (CH 2 )s, CH 3 or CH 3 -(CH 2 ) S , - it being understood that at least two groups among R20, R21, R22, R22a, R22b,
• R26, R27, R28, R29, R30 and R31 being identical or different and representing independently of each other H, (CH 2 ) S , CH 3 , CH 3 -(CH 2 ) S , O(CH 2 ) S , CH 3 O or CH 3 -(CH 2 ) S O, being understood that at least two groups among R26, R27, R28, R29, R30 and R31 represent (CH 2 )s or O(CH 2 ) S ,
• R32, R33, R34, R36, R36', R45, R47, R48 and R49 independently representing H, CH 3 or CH 3 (CH 2 ) r ,
• - B representing a hydrocarbon chain, linear or branched, comprising 12 to 30 carbon atoms, and comprising at least one double bond
• the at least one polyol (III) is such that L2 represents L2-2.
• r is an integer preferably ranging from 1 to 4, and preferably is equal to 1, 2 or 4.
• polyols (III) according to this embodiment we can cite the following polyols:
• the at least one polyol (III) is such that L2 represents L2-4.
• R20 and R21 are identical or different and represent (CH 2 ) S
• R22, R23, R24 and R25 are identical or different and independently represent H, CH 3 or CH 3 -(CH 2 ) S.
• polyols (III) according to this embodiment the following polyol may be cited:
• the at least one polyol (III) is such that L2 represents L2-6.
• R32 and R33 preferably independently represent H, CH 3 or CH 3 (CH 2 ) r with r representing an integer ranging from 1 to 4.
• polyol (III) according to this embodiment, the following polyol can be cited:
• the at least one polyol (III) is such that L2 represents L2-7.
• R34 preferably represents H, CH 3 OR CH 3 (CH 2 ) r with r ranging from 1 to 4.
• u preferably represents 1, 2 or 3.
• polyols (III) according to this embodiment the following polyols can be cited:
• the at least one polyol (III) is such that L2 represents L2-8.
• r represents an integer ranging from 1 to 4, and preferably equal to 1 or 2.
• R35 preferably represents CH 3 or CH 3 (CH 2 ) r with r preferably ranging from 1 to 4, and better being equal to 1 or 2.
• R35 represents HO(CH 2 ) r , with r representing an integer preferably ranging from 1 to 4, and in particular equal to 1 or 2.
• polyols (III) the following polyols may be cited:
• the at least one polyol (III) is such that L2 represents L2-9.
• R36 and R36' are identical or different and preferably independently represent H, CH 3 or CH 3 (CH 2 ) r with r representing an integer ranging from 1 to 4, preferably equal to 1 or 2.
• polyols (III) according to this embodiment the following polyols may be cited:
• the at least one polyol (III) is such that L2 represents L2-11.
• r preferably represents an integer ranging from 1 to 4, and preferably equal to 1 or 2.
• the at least one polyol (III) is such that L2 represents L2-12. According to this embodiment, u preferably represents 0 or 1. According to this embodiment, w preferably represents 0. As an example of polyol (III) according to this embodiment, the following polyol may be cited:
• the at least one polyol (III) is such that L2 represents L2-13.
• r preferably represents an integer ranging from 1 to 4, preferably r is equal to 1.
• R37, R38, R39, R40, R41, R42, R43 and R44 represent independently of each other H, CH 3 , CH 3 -(CH 2 )s, CH 3 O or CH 3 -(CH 2 ) S O, and preferably H, CH 3 O or CH 3 -( CH 2 ) S O, with s preferably representing an integer ranging from 1 to 12, preferably from 1 to 6.
• R37, R38, R43 and R44 preferably represent H.
• R39, R40, R41 and R42 are identical or different and independently represent a CH 3 O or CH 3 -(CH 2 ) S O group with s preferably representing an integer ranging from 1 to 12 , preferably 1 to 6.
• polyols (III) the following polyol can be cited:
• the at least one polyol (III) is such that L2 represents L2-14.
• R45 preferably represents H, CH 3 OR CH 3 (CH 2 ) r with r representing an integer ranging from 1 to 4, and preferably R45 represents H.
• R46 represents preferably (CH 2 ) r with r being equal to 3, 4 or 6, benzylene or cyclohexylene.
• z is preferably equal to 0 or 1.
• R46 CH 2 -Ph-CH 2 (III-14-4)
• the at least one polyol (III) is such that L2 represents L2-14'.
• R45 preferably represents H, CH 3 OR CH 3 (CH 2 ) r with r representing an integer ranging from 1 to 4, and preferably R45 represents CH 3 or CH 3 (CH 2 ) r with r representing an integer ranging from 1 to 4.
• R46 preferably represents (CH 2 ) r with r being equal to 3, 4 or 6, benzylene or cyclohexylene.
• z preferably represents 0.
• R46 CH 2 -Ph-CH 2 (III-14'-4)
• the at least one polyol (III) is such that L2 represents L2-15.
• 47 and R48 are identical or different and represent H, CH 3 or CH 3 (CH 2 ) r with r preferably representing an integer ranging from 1 to 4, preferably r being equal to 1 or 2
• z is equal to 0, 1 or 4.
• polyols (III) according to this embodiment the following polyols may be cited:
• the at least one polyol (III) is such that L2 represents L2-16.
• R49 preferably represents H, CH 3 OR CH 3 (CH 2 ) r with r representing an integer ranging from 1 to 4, from preferably r being equal to 1 or 2.
• z is equal to 0, 1 or 4.
• polyols (III) according to this embodiment the following polyols may be cited: (III-16-2).
• the at least one polyol (III) is such that L2 represents L2-17.
• L2-17 can represent a triester of hydroxylated unsaturated fatty acids, that is to say comprising a hydroxyl substituent on the carbon chain.
• the hydroxylated fatty acids are in particular chosen from ricinoleic acid, lesquerolic acid or densipolic acid.
• the at least one polyol is such that the group L2 is chosen from the groups L2-1, L2-2, L2-3, L2-4, L2-6 , L2-8, L2-9 and L2-10, as defined above, and preferably from L2-8 and L2-9.
• the polyurethane (I) is prepared from a polyoxamic acid (II) comprising two or three oxamic acid functions, and one or two polyols (III) each comprising two, three or four hydroxylated functions, it being understood that the number of oxamic acid functions and the number of hydroxylated functions cannot both be equal to two.
• the at least one polyoxamic acid of formula (II) is such that the group L1 is chosen from the groups Ll-1, Ll-1', Ll-2, Ll-6, Ll-9 and Ll-10, as defined above, and preferably from Ll-1 and Ll-2, and the at least one polyol (III) is such that L2 is chosen from the groups L2-1, L2-2, L2-3, L2-4, L2-6, L2-8, L2-9 and L2-10, as defined above, and preferably from L2-8 and L2-9.
• the reaction in step a) is carried out in the presence of an oxidant.
• an oxidant which may be suitable in the context of the invention, mention may in particular be made of hypervalent iodized oxidants such as bis(trifluoroacetoxy)iodobenzene, bis(acetoxy)iodobenzene (or iodobenzene diacetate), poly [4- ( diacetoxyiodo)styrene], hydroxybenziodoxole, and acetoxybenziodoxole.
• the oxidant is a hypervalent iodized oxidant chosen from bis(trifluoroacetoxy)iodobenzene, poly[4-(diacetoxyiodo)styrene] (or polystyrene iodoacetate), and bis(acetoxy)iodobenzene (or diacetate iodobenzene).
• the iodized oxidant hypervalent is supported, for example on a polymer, such as poly[4-(diacetoxyiodo)styrene].
• the hypervalent iodized oxidant is not supported, and is preferably chosen from bis(trifluoroacetoxy)iodobenzene, and bis(acetoxy)iodobenzene.
• the molar ratio of oxidant relative to the oxamic acid functions ranges from 1 to 1.2, and preferably equal to 1.1.
• the oxamic acid: hydroxyl functional ratio ranges from 0.8:1 to 1.3:1, preferably from 0.9:1 to 1.1:1. According to a particularly preferred embodiment, the oxamic acid: hydroxyl functional ratio is 1.1: 1.
• oxamic acid: hydroxyl functional ratio we mean the ratio between the number of oxamic acid functions of the polyoxamic acid(s) and the number of hydroxyl functions of the polyol(s) . In other words, this ratio is equal to (x * number of moles of polyoxamic acid(s)) / (y * number of moles of polyol(s)).
• the reaction in step a) is carried out in the presence of a surfactant (IV).
• a surfactant IV
• the surfactant is optional, satisfactory results being obtained with or without surfactant.
• the process is carried out in an open reactor, it is more advantageous for the surfactant to be present, although it is not essential.
• the surfactant (IV) is preferably non-ionic.
• nonionic surfactants which may be suitable in the context of the invention, mention may be made of silicone surfactants, and in particular those of the formulas below:
• R50 represents OH.
• step a) between the at least one polyoxamic acid and the at least one polyol generates in particular carbon dioxide, which is used during the step of foaming the polyurethane (I).
• Step b) of the process according to the invention makes it possible to foam the polyurethane (I) obtained in step a).
• the foaming step is carried out solely using the carbon dioxide generated during the synthesis of the polyurethane.
• the carbon dioxide generated in step a) is then the foaming agent. So, advantageously, the synthesis of the polyurethane (step a)) and the foaming step (step b)) can be carried out concomitantly.
• step c), subsequent to step b), can be carried out in order to purify the polyurethane foam (I) obtained by eliminating reaction by-products.
• the polyurethane foam can be heated and/or put under reduced pressure, using a vacuum oven for example.
• the foam is preferably heated to a temperature ranging from 60°C to 150°C, preferably from 80°C to 130°C, and/or placed under reduced pressure. This step is not obligatory.
• the invention also relates to the polyurethane foam (I) obtained according to the process of the invention.
• This foam advantageously has physicochemical properties comparable to those obtained by processes described in the prior art.
• the polyurethane foam (I) can have a density ranging from 10 to 1000 kg.m 3 , preferably from 100 to 300 kg.m 3 .
• the density d corresponds to the apparent density of the foam, that is to say the ratio of the mass m and the apparent volume V of the foam.
• the mass m can be measured with a balance and the apparent volume V can be determined by measuring the dimensions of the foam with a caliper.
• the polyurethane foam obtained has a porous structure.
• the cells (or pores) of the polyurethane foam can have a diameter of between 0.1 mm and 2 mm, preferably between 0.2 mm and 1.5 mm, the diameter being measured using a microscope scanning electronics at 50 Pa and 7.00 kV on sections transverse to the direction of expansion of the material.
• the cells or pores of polyurethane foam correspond to the empty spaces in the foam.
• Nine polyurethane foams according to the invention were prepared according to the following processes. [01841 Process for the synthesis of oxamial acids:
• Triethylamine (11 mmol) was added to a solution of amine (10 mmol) in dichloromethane (concentration: 0.3 M) at room temperature. The solution was then cooled to 0°C and then ethyl oxalyl chloride (11 mmol) was added dropwise. The solution was then slowly brought back to room temperature over a period of 4 to 6 hours while being kept stirring. The reaction was then treated with hydrochloric acid solution (1 M, 20 mL) and then extracted with dichloromethane (3 x 20 mL). The organic phases were combined then washed with saturated sodium chloride solution. The resulting organic phase was then dried over sodium sulfate, filtered and then concentrated under reduced pressure.
• the polyol(s) and the surfactant were introduced into an open reactor.
• the oxidant and polyoxamic acid were ground and mixed together in a separate reactor, and then introduced into the reactor containing the polyol(s).
• the reaction mixture was mixed using a spatula then by magnetic stirring.
• the reactor was heated to a temperature of 80°C, 100°C, 115°C or 130°C, depending on the reactants.
• the reaction mixture was stirred once the reaction mixture reached a homogeneous liquid state and foam began to form.
• the height of the mousse was stable, it was cooked for 2 hours at this temperature. Once cooking finished, the reactor was cooled to room temperature (RT).
• the foam is then placed in a vacuum oven at 60°C for 5 hours.
• the oxidant and polyoxamic acid were ground and mixed together in a separate reactor, and then introduced into the reactor containing the polyol(s).
• the reaction mixture was mixed using a spatula then by magnetic stirring.
• the reactor was closed and then heated to a temperature of 100°C.
• the reaction mixture was stirred once the reaction mixture reached a homogeneous liquid state.
• the reactor was opened.
• the foam obtained was subjected to a dynamic vacuum for 5 minutes, then was cooked for 2 hours at 100°C under static vacuum. After the cooking was completed, the reactor was cooled to room temperature (RT) before opening.
• the foam is then placed in a vacuum oven at 60°C for 5 hours.
• compositions of polyurethane foams are detailed in Table 1 below. The percentages are mass percentages relative to the total weight of the reactants in the reaction mixture.
• the ethoxylated trimethylol propane used has a number average molar mass Mn of 1014 g. mol 1 .
• the physicochemical characteristics of the nine polyurethane foams were evaluated, and are detailed in Table 2 below.
• the foaming time TM corresponds to the formation and stabilization time of the foam, that is to say the time from which the maximum height of foam in the reactor is obtained.
• the density d corresponds to the apparent density of the foam, that is to say the ratio of the mass m and the apparent volume V of the foam. The mass was measured with a balance and the apparent volume V was determined by measuring the dimensions of the foam with a caliper.
• the glass transition temperature Tg was measured by DSC, using DSC Q100 equipment from TA Instruments. For each polyurethane foam, two heating cycles from -75°C to 200°C, with a ramp of 10°C.
• the glass transition temperature was determined from the second cycle.
• the degradation temperature T d5 o /o corresponds to the temperature at which the polyurethane foam loses 5% of its initial mass.
• the degradation temperature T d5 o /o was determined by thermogravimetric analysis (TGA), carried out on a TGA-Q500 instrument from TA Instruments, under a dinitrogen atmosphere, heating at 10°C. min 1 from room temperature to 600°C.
• TGA thermogravimetric analysis
• the mechanical properties are determined in compression by DMA, using DMA Q850 equipment from TA Instruments, by measuring the stress making it possible to reach 50% deformation relative to the initial height of the samples, with a prestress of 0.02 N and a ramp of 100%/min.
• the morphologies of the foam cells are evaluated using a FEI QUANTA 200 scanning electron microscope (SEM) at 50 Pa and 7.00 kV on sections transverse to the direction of expansion of the material. Cell diameters are measured using ImageJ software and averaged for a minimum of 100 cells per sample.
• the measured Tg range from -33.2°C to -47.6°C except for PU3, which is comparable to what has been described in the literature for polyurethane foams synthesized from propylene. glycol and toluene diisocyanate in the presence of a silicone surfactant (Armistead et al., Journal of Applied Polymer Science, 1988, Vol. 35, pp. 601-629). Synthesis in an open or closed reactor has no influence on the Tg of the foam obtained.
• the measured densities range from 112 kg.nT 3 to 318 kg.nT 3 . Densities of the same order of magnitude have been reported in the literature for polyurethane foams synthesized from trifunctional propylene glycol and a mixture of 4,4'-diphenylmethylene diisocyanate (MDI) and toluene diisocyanate (TDI). , in the presence of a silicone surfactant (Gwon et al., International Journal of Precision Engineering And Manufacturing, 2015, Vol. 16, No. 11, pp. 2299-2307).
• MDI 4,4'-diphenylmethylene diisocyanate
• TDI toluene diisocyanate
• the cell diameters of the PU1 to PU9 foams range from 0.26 mm to 1.23 mm, which is of the same order of magnitude as what is described in the literature (Gwon et al., International Journal of Precision Engineering And Manufacturing, 2015, Vol. 16, No. 11, p. 2299-2307; Yi et al. ; Journal of Applied Polymer Science 2020, 7 7(46). DOI: 10.1002/app.49510).
• Figure 1 is a photograph of PU2 allowing the macroscopic appearance of the foam formed to be visualized.
• Figure 2 shows the porous structure of PU2 foam observed under a scanning electron microscope.
• the constraint making it possible to achieve 50% deformation relative to the initial height of the samples ( 5 o% constraint) for foams prepared in an open reactor ranges from 0.9 kPa to 23.3 kPa, which is comparable to which is described in the document Yi et al. for a deformation of 10%.
• the 50 o /o stress was measured at 89.4 kPa.

Landscapes

• 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)
• Materials Engineering (AREA)
• Polyurethanes Or Polyureas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=81648193

Family Applications (1)

Country Status (3)

• 2022
  • 2022-03-21 FR FR2202487A patent/FR3133614B1/fr active Active
• 2023
  • 2023-03-17 EP EP23716633.5A patent/EP4496830A1/de active Pending
  • 2023-03-17 WO PCT/FR2023/050378 patent/WO2023180658A1/fr not_active Ceased

Also Published As

Similar Documents

Legal Events