摘要:
A method whereby the properties, particularly the recrystallisation temperature, of thermoplastic polyurethane elastomers, particularly those suitable for processing by extrusion, are kept constant during continuous manufacture in screw-type extruding machines by continuously adding substantially straight-chain hydroxyl-terminated polyols having a molecular weight of 500 to 5000, organic diisoicyanates and diol and optionally triol chain-lengthening agents having a molecular weight of 62 to 500, the molar ratio of polyols to chain-lengthening agents being 1:1 to 1:5, and by continuous addition of a catalyst, wherein the recrystallisation temperature is set at a value at least 2.degree. C. below the value for the corresponding TPU manufactured without a catalyst, and when the set recrystallisation temperature is exceeded, the amount of continuously supplied catalyst is increased, whereas when the value falls below, the amount is decreased so as to maintain the set value, the resulting elastomers and use thereof for extrusion.
摘要:
A process for the continuous production of a thermoplastic molding composition containing a mixture of TPU and a (co)polymer is disclosed. The process comprises (a) introducing into an extruder under time and temperature conditions sufficient to bring about the formation of thermoplastic polyurethane a (co)polymer, and polyurethane-forming components comprising A) an organic diisocyanate, B) a linear polyol having terminal hydroxyl groups and a molecular weight of 500 to 5000, and C) a chain extender having a molecular weight of 60 to 500, and upon completing the formation of said polyurethane (b) discharging the resulting TPU/(co)polymer mixture from the extruder. Importantly, the (co)polymer contains a flow enhancer and the molar ratio of the NCO groups in A) to the groups which react with NCO in B) and C) is 0.9 to 1.2.
摘要:
A process for the continuous production of a thermoplastic molding composition containing a mixture of a TPU and a thermoplastic (co)polymer is disclosed. The process comprises (i) introducing into an extruder via a first feed point component I) with at least 3% by weight, with respect to component I), of at least one member selected from the group consisting of components A), B) and C), and(ii) metering in the balance of said A), B) and C) into said extruder via one or more subsequent feed points, (iii) extruding components I) and II) under conditions sufficient to cause A), B) and C) reaction to form TPU, and (iv) upon the completion of said reaction, removing the resulting mixture of TPU and (co)polymer from the extruder, wherein component I) comprises 1 to 60% by weight, with respect to the total mixture, of a thermoplastic (co)polymer, and wherein component II) comprises 99 to 40% by weight, with respect to the total mixture, of the polyurethane-forming components including A) an organic diisocyanate, B) a linear polyol having terminal hydroxyl groups and a number average molecular weight of 500 to 5000, and C) a chain extender having a molecular weight of 60 to 500, and wherein the molar ratio of NCO groups in A) to the groups which react with NCO in B) and C) is in the range of 0.9 to 1.2.
摘要:
A thermoplastic composition comprising aliphatic polyurethane is disclosed. The composition is charactrized in having a post weathering yellow value lower than 20 and good hardness and softening temperature values both before and after weatering for 504 hours in accordance with ISO 4892.
摘要:
A process for the continuous production of a thermoplastic molding composition containing a mixture of a TPU and a thermoplastic (co)polymer is disclosed. The process comprises(i) introducing into an extruder via a first feed point component I) with at least 3% by weight, with respect to component I), of at least one member selected from the group consisting of components A), B) and C), and(ii) metering in the balance of said A), B) and C) into said extruder via one or more subsequent feed points,(iii) extruding components I) and II) under conditions sufficient to cause A), B) and C) reaction to form TPU, and(iv) upon the completion of said reaction, removing the resulting mixture of TPU and (co)polymer from the extruder,wherein component I) comprises 1 to 60% by weight, with respect to the total mixture, of a thermoplastic (co)polymer, and wherein component II) comprises 99 to 40% by weight, with respect to the total mixture, of the polyurethane-forming components including A) an organic diisocyanate, B) a linear polyol having terminal hydroxyl groups and a number average molecular weight of 500 to 5000, and C) a chain extender having a molecular weight of 60 to 500, and wherein the molar ratio of NCO groups in A) to the groups which react with NCO in B) and C) is in the range of 0.9 to 1.2.
摘要:
The invention relates to a new process for the production of compounds containing at least one hydantoin ring by reacting a carbodiimide with a derivative of an .alpha.,.beta.-unsaturated carboxylic acid corresponding to the following general formula: ##STR1## wherein R.sup.3, R.sup.4 and R.sup.5 are as defined in the description.
摘要:
A thermoplastsic molding composition comprising thermoplastic polyurethane resin and about 0.05 to 2 percent of a wax is disclosed. The composition which offers processing advantages, including release and cosmetic properties, is characterized in that the wax contains acylation products of hydroxy groups and of amino groups of amino alcohols.
摘要:
Polyesters having at least 90%, by weight, of recurrent structural units corresponding to the following formula: ##STR1## and characterised by a relative viscosity.eta..sub.rel of from 1.6 to 4.5 (determined at 25.degree. C. in CH.sub.2 Cl.sub.2, c=5 g/l) are suitable for the production of films having highly advantageous performance characteristics, in particular high heat resistance.
摘要:
The present invention relates to polycarbonate laminates consisting of an electrically conductive polycarbonate layer (A) containing carbon black or graphite, and an electrically insulating polycarbonate layer (B), their preparation and their use in the electrical sector.
摘要:
The present invention is directed to the use of polymer blend films consisting of polycarbonate and polyalkylene terephthalate supports for diagnostic test strips.