摘要:
The present invention relates to an improved continuous process for the preparation of polyurethane elastomers which are distinguished from the products produced by known processes by increased elasticity, reduced shrinkage, higher rigidity (limit bending stress), improved cold notched bar impact resistance and good thermal stability.
摘要:
The instant invention is directed to a continuous process for the production of thermoplastic materials, comprising:I. introducing 4 to 65 parts by weight of thermoplastic polymer into an extruder at a first inlet, wherein the temperature within said extruder is such that said thermoplastic polymer melts;II. adding to said thermoplastic polymer through a second inlet 35 to 96 parts by weight of the following polyurethane forming components, such that the total parts by weight of thermoplastic polymer and polyurethane components is 100:(A) organic polyisocyanate; and(B) chain lengthening agent with a molecular weight below 400 containing a hydroxyl group and/or amine group;wherein the ratio of isocyanate groups of component (A) to Zerewitinoff active groups of component (B) is in the range of from 0.90:1 to 1.2:1; andIII. discharging from the extruder the product of the process when the reaction of said polyurethane components (A) and (B) is substantially complete.
摘要:
The instant invention is directed to a process for the modification of a thermoplastic polymer comprising:I. introducing 70 to 98 parts by weight of thermoplastic polymer into an extruder at a first inlet;II. adding to said thermoplastic polymer through a second inlet 2 to 30 parts by weight of the following polyurethane forming components, such that the total parts by weight of the thermoplastic polymer and polyurethane components is 100:(A) organic polyisocyanate; and(B) chain lengthening agent with a molecular weight below 400 containing at least one hydroxyl group and/or amino group; wherein the ratio of isocyanate groups of component (A) to Zerewitinoff active groups of component (B) is in the range of from 0.90:1 to 1.2:1; andIII. discharging from the extruder the product of the process.
摘要:
The instant invention is directed to the discovery that it is now possible to obtain high quality, elastomeric polyurethanes or polyureas, even when using highly reactive diamines as chain lengthening agents, without the formation of unwanted irregularities, if the mixture of reactants is exposed to a high velocity gradient by means of vigorously mixing kneading elements at an early phase of the reaction while the viscosity of the reaction mixture is still low. Generally, the viscosity is kept between 100 and 1000 poises and preferably between 200 and 700 poises during the action of the high velocity gradient.
摘要:
A process for preparing bisphenol A which has a purity of at least 99.95 wt. % of p,p-bisphenol A (BPA). Thermally stable and colour-stable BPA purified in accordance with the invention produces improved thermal and colour stability and improved optical transparency in polymers such as e.g. polycarbonates prepared therefrom.
摘要:
Homo- and/or copolymers of one or more ethylenically unsaturated monomers, suitable for the preparation of molded articles that feature improved properties, especially improved fracture properties, heat stability and notched impact strength are disclosed. These homo- and/or copolymers are characterized in that they contain less than 400 particles per m2 of surface area with a diameter greater than 200 μm.
摘要:
The invention relates to a process for the synthesis of bis-(4-hydroxyphenyl)-alkanes on ion-exchange resins or mixtures of ion-exchange resins which are modified with alkyl-SH groups, wherein the monophenols and carbonyl compounds to be used have first been purified to remove substances which can transfer alkyl groups.
摘要:
A method for producing bisphenol A in prill form is disclosed. Molten bisphenol is top-fed into a prilling tower via a plate containing a plurality of nozzles. A gas coolant guided through a circuit is led into said tower in a counter flow direction. The prills are cooled to about room temperature, collected at the bottom of the tower and removed. Also disclosed is the device for carrying out the inventive method and the prills thus produced.
摘要:
The invention relates to a process for the production of bisphenols from acetone and phenols in the presence of sulfonic acid ion exchanger resins modified with alkyl-SH groups, in which 0.6 to 5% by weight H.sub.2 O is added to the mixture of phenol and acetone before the reaction.
摘要翻译:本发明涉及一种在烷基-SH基团改性的磺酸离子交换树脂存在下由丙酮和酚生产双酚的方法,其中在苯酚和丙酮的混合物中加入0.6-5重量%的H 2 O. 反应。