Abstract:
A multilayer structure based on polyamides, comprising: a first layer (1) formed from a polyamide P1 or from a blend of a polyamide P1 and a polyolefin PO1 having a P1 polyamide matrix, optionally, a layer (2a) formed from EVOH; a layer (2) formed from a blend of PA-6/12 copolyamides, one comprising by weight more 6 than 12 and the other more 12 than 6; a layer (3) formed from a polyamide P3, it being possible for P1 and P3 to be identical or different, the layers (1), (2), (2a) and (3) being successive and adhering to one another in their respective contact regions.
Abstract:
The process for the continuous preparation of homopolymers or copolymers by free-impinging-jet micromixing of fluids formed (1) of monomer(s) and (2) of an initiator system consists in micromixing the said fluids (1) and (2) and in recovering the mixture of these fluids in the form of a resultant jet Jr, originating from the point of impingement (I), the micromixture being obtained by: a) forming at least one group of at least two jets Ja of the said identical or different fluids, these jets coinciding at a point of impingement (I), the jets Ja of the same group all being of identical geometry, their axes being arranged such that their projections on a plane perpendicular to the axis (A) of the resultant jet Jr are distributed angularly in a uniform manner and these axes being inclined relative to the said axis (A) by the same non-zero angle null of not more than 90null; b) simultaneously directing at the point of impingement (I) at least one jet Jb of a fluid which is different from at least one of the fluids of the said jets Ja for forming the resultant jet Jr, the axis of the jet(s) Jb being inclined relative to the axis of the resultant jet Jr by an angle null which is less than the angle null; and c) recovering the mixture of the fluids in the jets Ja and Jb in the form of the resultant jet Jr consisting of the homopolymers or copolymers.
Abstract:
Improved thermoplastic liner containing metal pipelines in which the liners consist essentially of polyamide 11 or polyamide 12 as well as methods for their preparation and use are disclosed.
Abstract:
The invention relates to a composition based on polypropylene homopolymer or copolymer and on an impact modifier comprising an ethylene/alkyl acrylate copolymer. This composition comprises substantially between 1 and 40% by weight of impact modifier and it may comprise an ethylene-based copolymer taken from the group comprising ethylene/acrylate copolymers, vinyl acetate copolymers, polyethylene obtained by metallocene catalysis or mPE and linear low-density polyethylene or LLDPE. The PP thus modified is useful for manufacturing motor-vehicle parts for example of the bumper or dashboard type, requiring good thermomechanical strength over a wide range of temperatures.
Abstract:
The present invention relates to an isotactic polypropylene obtained by metallocene catalysis, onto which is grafted a functional monomer. The invention also relates to a composition which may form part of the composition of a coextrusion binder. This composition according to the invention comprises isotactic polypropylene obtained by metallocene catalysis, grafted and then optionally diluted with at least one polyolefin (C1) and/or in at least one polymer of elastomeric nature (D). The invention also relates to a multilayer structure comprising a layer (L) comprising the above binder, and, directly attached thereto, a layer (E): which is polar, nitrogenous or oxygenated, such as a layer of polyamide resin, of ethylene/saponified vinyl acetate copolymer (EVOH) or of polyester; or of a mineral oxide deposited on a polymer such as polyethylene (PE), polyethylene terephthalate (PET) or EVOH; or which is metallic or metalloplastic.
Abstract:
A structure made of a fluoropolymer layer and directly attached to one of its sides a tie layer based on a polyamide which results from the condensation of at least one diacid and at least one diamine of the following formula (1): 1 in which R1 represents H or nullZ1nullNH2 and Z1 represents an alkyl, a cycloalkyl or an aryl having up to 15 carbon atoms and R2 represents H or nullZ2nullNH2 and Z2 represents an alkyl, a cycloalkyl or an aryl having up to 15 carbon atoms, it being possible for R1 and R2 to be identical or different. The tie resin may also be a copolymer having polyamide blocks and polyether blocks, the polyamide blocks resulting from condensation of at least one diacid and at least one diamine of formula (1). The invention also relates to a structure comprising a fluoropolymer layer, the tie layer and a substrate layer, respectively, as well as to a structure comprising a tie layer, respectively. This structure may be placed between two substrate layers and may be in the form of a sheet, film, profile or tube. It is particularly useful in the form of a tube for transporting gasoline between the tank and the injection device in motor-vehicle engines.
Abstract:
2-Ethylhexyl acrylate is obtained by esterification of acrylic acid (AA) with 2-ethylhexanol (2-EtHexOH), in the presence of at least one stabilizer for AA, with H2SO4 as catalyst, the crude reaction mixture (B1) obtained comprising the desired acrylate, 2-EtHexOH, AA, 2-ethylhexyl hydrogensulphate (2-EtHexSO4H), traces of H2SO4 and impurities. (B1) is washed with water in an extraction column C2 to remove, at the bottom, the aqueous phase (A1), the top organic phase (O2) being sent to a topping column C3 to obtain, at the top, the AA and the 2-EtHexOH, which are recycled to the esterification, the topped desired acrylate being sent to a distillation column C4, from where it exits, purified from the heavy products; a stage of hydrolysis of the 2-EtHexSO4H present in (A1) being carried out to form, in this phase, 2-EtHexOH and H2SO4, the acidic entities resulting from the hydrolysis being neutralized by introduction of a base into the medium, and the resulting aqueous phase (A3) being sent to the recovery of the 2-EtHexOH in a distillation column C1.
Abstract translation:丙烯酸2-乙基己酯通过丙烯酸(AA)与2-乙基己醇(2-EtHexOH)在至少一种AA稳定剂的存在下与H 2 SO 4作为催化剂进行酯化而获得,所得的粗反应混合物(B1)包含 所需的丙烯酸酯,2-EtHexOH,AA,2-乙基己基硫酸氢盐(2-EtHexSO 4 H),痕量H 2 SO 4和杂质。 (B1)在萃取塔C2中用水洗涤以在底部除去水相(A1),将顶部有机相(O 2)送至顶部塔C3,以在顶部获得AA和 被再循环至酯化的2-EtHexOH,将顶部所需的丙烯酸酯从其出口排出到蒸馏塔C4中,从重产物中纯化; 在(A1)中存在的2-EtHexSO 4 H的水解阶段在该相中进行以形成2-EtHexOH和H 2 SO 4,由水解产生的酸性实体通过将碱引入培养基而中和, 得到的水相(A3)送入蒸馏塔C1中的2-EtHexOH的回收。
Abstract:
Process for preparing a compound (I) by reacting a compound of formula (II) with the alcohol (III). The reaction is carried out using dibutyltin oxide as transesterification catalyst. 1 R1nullH or CH3 R2nulllinear C1-C4 alkyl radical.
Abstract:
2-Ethylhexyl acrylate is manufactured according to a process for the direct esterification of acrylic acid with 2-ethylhexanol catalysed by sulphuric acid, the acrylic acid subjected to the esterification being stabilized by at least one stabilizing agent, the said esterification being followed by the neutralization by a base of the crude reaction mixture (B1) obtained, the resulting salts passing into the aqueous phase (A1) of the said mixture, the organic phase (O1) and the aqueous phase (A1) resulting from this neutralization being separated and the 2-ethylhexyl acrylate being recovered from the organic phase (O1). To suppress the emulsions which appear during the said neutralization, the stabilizer or stabilizers of acrylic acid is/are chosen with the exclusion of hydroquinone, in the absence of which the aqueous phase of the process is stabilized before and/or during the neutralization.
Abstract:
Thermally stabilized initiator compositions comprising: (a) at least one dialkyl peroxydicarbonate, and (b) a stabilizing effective amount of a compound of Structure I: 1 wherein R1 and R2 are as defined in the summary of the invention section, processes for their preparation and use are disclosed.