摘要:
The invention relates to a process for simultaneously performing two chemically successive reactions in a loop reactor, specifically reaction I) an optionally catalyzed equilibrium reaction between high-boiling liquid reactants, in which essentially one high boiler is formed as an intermediate and at least one low boiler as a by-product, and reaction II) a substantially diffusion-controlled reaction in which the liquid intermediate is reacted with at least one gaseous reactant to give the end product, wherein reactions (I) and (II), optionally after a start phase, are allowed to proceed simultaneously in the same apparatus, specifically loop reactor, and the loop reactor has a connectable gas-liquid circulation system coupled via an ejector mixing nozzle, in which circulated liquid phase is mixed in the ejector mixing nozzle with newly supplied gaseous reactant of reaction (II) (6) and/or gaseous reactant of reaction (II) aspirated by means of the ejector from the reactor via a connectable condenser (5), and fed to the reactor by a liquid jet ejector (2) for the reaction, the low-boiling by-product(s) of reaction (I) and also any low-boiling solvent being condensed and discharged in the condenser continuously over the duration of the process. In particular, the invention relates to a process for etherifying high-boiling polyether alcohols.
摘要:
Polysiloxane-polyoxyalkylene block copolymers having different polyoxyalkylene blocks in the average molecule are prepared. The mixture of the polyoxyalkylene blocks consists of at least one polyoxyalkylene group A and at least one polyoxyalkylene group B and/or at least one polyoxyalkylene group C, each polyoxyalkylene group A having an average molecular weight of 600 to 5,500 and consisting of 20 to 90% by weight of oxyethylene units and 80 to 10% by weight of oxypropylene units, polyoxyalkylene group B having an average molecular weight of 500 to 5,000 and consisting of 2 to 19% by weight of oxyethylene units and 98 to 81% by weight of oxypropylene units, polyoxyalkylene group C having an average molecular weight of 1,500 to 4,500 and consisting of oxypropylene units. Up to 20% by weight of the oxypropylene units is replaceable by oxybutylene units and the molar ratio of polyoxyalkylene groups A to the sum of the polyoxyalkylene groups B and C is 1:4 to 4:1. The block copolymers are highly effective stabilizers for the production of flexible polyurethane foams with an excellent ratio of cell fineness of the foam to air permeability of the foam.
摘要:
A method for the preparation of flexible foams containing urethane groups and having a reduced hardness is disclosed. Polyethers, having at least two hydroxyl groups and a molecular weight of 400 to 12,000 are reacted with polyisocyanates in the presence of catalysts and water and, optionally, in the presence of emulsifiers, stabilizers, cross linking agents, blowing agents and conventional auxiliaries and additives. The method is carried out in the presence of 0.01 to 1.0 parts by weight, based on 100 parts by weight of the polyol, of the alkali salt or the alkaline earth metal salt of a hydroxycarboxylic acid. The method enables the use of chlorofluorocarbons to be omitted largely or completely as physical blowing agents.
摘要:
The invention relates to a process for simultaneously performing two chemically successive reactions in a loop reactor, specifically reaction I) an optionally catalyzed equilibrium reaction between high-boiling liquid reactants, in which essentially one high boiler is formed as an intermediate and at least one low boiler as a by-product, and reaction II) a substantially diffusion-controlled reaction in which the liquid intermediate is reacted with at least one gaseous reactant to give the end product, wherein reactions (I) and (II), optionally after a start phase, are allowed to proceed simultaneously in the same apparatus, specifically loop reactor, and the loop reactor has a connectable gas-liquid circulation system coupled via an ejector mixing nozzle, in which circulated liquid phase is mixed in the ejector mixing nozzle with newly supplied gaseous reactant of reaction (II) (6) and/or gaseous reactant of reaction (II) aspirated by means of the ejector from the reactor via a connectable condenser (5), and fed to the reactor by a liquid jet ejector (2) for the reaction, the low-boiling by-product(s) of reaction (I) and also any low-boiling solvent being condensed and discharged in the condenser continuously over the duration of the process. In particular, the invention relates to a process for etherifying high-boiling polyether alcohols.
摘要:
The invention relates to a method for the production of high resilience polyurethane foams by reacting a mixture of highly reactive polyols, which usually have an average molecular weight of between about 4800 and 6500 g/mole and at least 70% primary hydroxyl groups and optionally contain fillers, polyfunctional isocyanates, amine activators, cross-linking agents, tin catalysts, blowing agents and stabilizers, compounds of the general formula ##STR1## being used as stabilizers, in which R.sup.1 is the same or different in the average molecule and represents a methyl group or a group of the general formula --CH.sub.2 --CH.sub.2 --(CH.sub.2).sub.a --C.sub.6 H.sub.3 (R.sup.2).sub.2 (a=0 or 1; R.sup.2 =--O--CH.sub.3), with the proviso that at least one R.sup.1 group is a group having the formula --CH.sub.2 --CH.sub.2 --(CH.sub.2)a--C.sub.6 H.sub.3 (R.sup.2).sub.2n has an average numerical value of 2 to 11,m has an average numerical value of 1 to 6,with the proviso that the quotient p=(n+m+2)/m is 1.66 to 12.
摘要:
Polysiloxane-polyoxyaikylene block copolymers, which are intended for the production of polyurethane foams, are prepared. The foams obtained have an improved, finer cell structure and the collapse of the foams is reduced. It is essential for the invention that a mixture of polyoxyalkylene groups is present in the polysiloxane-polyoxyalkylene block copolymers. Further particulars are laid down for selecting the different polyoxyalkylene groups with regard to the respective molecular weights and the ratio of polyoxyalkylene groups to one another.
摘要:
The invention relates to a process for preparing polyethers of the formula (I) R1—(CHR2CHR3—O)n—H (I) where n=1 to 12 000, R1=a radical comprising at least one carbon atom and R2 and R3 are each independently H or a hydrocarbon radical, where the units designated with the index n may be the same or different (the R2 and R3 radicals in the different units n may thus be the same or different), by alkoxylating a starter compound which comprises the R1 radical in the presence of a double metal cyanide catalyst (DMC catalyst) in a loop reactor, which is characterized in that the alkoxylation is performed in a loop reactor which has an ejector mixing nozzle, in which all substances involved in the reaction or assistants can be added to the circulated reaction mixture, an alkylene oxide or a plurality of different alkylene oxides being metered into the reaction mixture via the ejector mixing nozzle at the same time (random addition) or at different times (block addition).
摘要:
High resilience polyurethane foams are produced by reacting a mixture of highly reactive polyols having a weight average molecular weight between about 4800 and 6500 g/mole and containing at least 70% primary hydroxyl groups and optionally fillers, polyfunctional isocyanates, amine activators, cross-linking agents, tin catalysts, blowing agents and stabilizers. The inventive stabilizers can be used universally in high resilience slabstock foam systems as well as in high resilience molded foam systems and in formulations based on pure TDI, TDI/MDI mixtures as well as on pure MDI in combination with appropriate polyols.
摘要:
The invention relates to a process for preparing polyethers of the formula (I) R1—(CHR2CHR3—O)n—H (I) where n=1 to 12 000, R1=a radical comprising at least one carbon atom and R2 and R3 are each independently H or a hydrocarbon radical, where the units designated with the index n may be the same or different (the R2 and R3 radicals in the different units n may thus be the same or different), by alkoxylating a starter compound which comprises the R1 radical in the presence of a double metal cyanide catalyst (DMC catalyst) in a loop reactor, which is characterized in that the alkoxylation is performed in a loop reactor which has an ejector mixing nozzle, in which all substances involved in the reaction or assistants can be added to the circulated reaction mixture, an alkylene oxide or a plurality of different alkylene oxides being metered into the reaction mixture via the ejector mixing nozzle at the same time (random addition) or at different times (block addition).
摘要:
The invention relates to the use of metal salts of ricinoleic acid or solutions thereof in water or in organic solvents in producing polyurethane foams.