摘要:
Disclosed herein is a process for preparing heat-resistant polymers by reacting an organic polyisocyanate with one or more compounds selected from the group consisting of organic polycarboxylic acids and organic polycarboxylic acid anhydrides in the presence of an alkali metal fluoride or an alkali metal fluoride combined with a quaternary onium salt as a catalyst.
摘要:
Disclosed is a process for the preparation of polyamide compounds by reacting at least one polycarboxylic acid with at least one diisocyanate in the presence of a catalyst comprising at least one mono-alkali metal salt of dicarboxylic acid. The polyamide compounds prepared by this process have a substantially linear configuration and a high degree of polymerization and, therefore, are suitable for the manufacture of fibers, films and molded articles.
摘要:
Disclosed is a catalyst for polymerizing .alpha.-olefins which comprises(A) a composition obtained by co-comminuting(a) a magnesium halide,(b) an organic acid ester,(c) a halogenated aliphatic or alicyclic hydrocarbon,(d) at least one ingredient selected from the group consisting of aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated aromatic hydrocarbons, liquid propylene oligomers and aromatic ethers, and(e) an aluminum halide optionally added thereto and then heat-treating the resulting mixture together with titanium tetrachloride;(B) an organic aluminum compound; and(C) an organic acid ester or a complex thereof with an aluminum halide.
摘要:
Aromatic polyamide having good high-temperature resistance and processing ability is obtained by specifying the ratio of storage modulus at the glass transition temperature (Tg).degree.C. to that of (Tg+100).degree.C.
摘要:
Disclosed herein is a process for preparing heat-resistant polymers by reacting an organic polyisocyanate with one or more compounds selected from the group consisting of organic polycarboxylic acids and organic polycarboxylic acid anhydrides in the presence of an alkali metal fluoride or an alkali metal fluoride combined with a quaternary onium salt as a catalyst.
摘要:
The present invention relates to an electromagnetic spring clutch. A conventional field core is formed in a bottomed cylindrical shape, so manufacturing such a field core is troublesome and uneconomical. When a through-hole through which shafts are inserted is provided in one or both of vertical walls of a U-shaped plate, a field core is provided simply and inexpensively.
摘要:
Heat resistant organic fibers comprising a wholly aromatic polymer having amide group and/or imide group, said fibers having properties satisfying the following formulasTm.gtoreq.350.degree. C.,Tm-Tex.gtoreq.30.degree. C.Xc.gtoreq.10%DE.gtoreq.10%DSR(Tm).ltoreq.15%, and ##EQU1## wherein Tm is a melting point; Tex is an exotherm starting temperature; Xc is a degree or crystallization; DE is an elongation; DSR is a dry shrinkage factor at Tm; and DSR(Tm+55.degree. C.) is a dry shrinkage factor at Tm+55.degree. C. The process for producing the fibers is also disclosed.
摘要:
An electromagnetic spring clutch has an armature (40) which can be moved to and from in the axial direction thereof and cannot be rotated on the axis, and which is biased by a spring (46), and a coil spring (36) which covers over outer faces of a master driving axle (30) and a slave driving axle (34) and which is capable of being wound tightly in the rotational direction of the master driving axle (30). When an electromagnetic coil (20) is not energized, an engagement section (44a) at the end of the armature (40) and a hook (38) of the coil spring (36) are engaged to expand the inner diameter of the coil spring (36) and disconnect the master driving axle (30) and the slave driving axle (34). When the electromagnetic coil (20) is energized to attract the armature (40) thereto against the biasing force of the spring (46), the engagement section (44a) and the hook (38) are disengaged to reduce the inner diameter of the coil spring (36) and connect the master driving axle (30) and the slave driving axle (34), whereby a prescribed rotational angle of the master driving axle (30) is transmitted to the slave driving axle (34).
摘要:
A polyamide and/or polyimide is prepared by using N,N'-dimethylethyleneurea or N,N'-dimethylpropyleneurea as a solvent upon polycondensation of a polycarboxylic acid and a diisocyanate at a temperature above 100.degree. C. in the presence of an alkali metal carbonate, alkali metal hydrogencarbonate, alkali metal hydroxide or an alkali metal salt of a polycarboxylic acid.
摘要:
A catalyst for polymerizing .alpha.-olefins composed of a titanium composition formed by heating a co-comminuted mixture of a magnesium halide and a complex of an aluminum halide and a carboxylic acid ester of the formula R.sup.1 COOR.sup.2, with titanium tetra-chloride; and an organic aluminum compound of the formula AlR.sup.3 mH.sup.3 --m; and optionally added thereto at least one component selected from an alkyl aluminum halide of the formula AlR.sup.4 nX.sub.3 --n; a carboxylic acid ester of the formula R.sup.5 COOR.sup.6 ; and its complex formed with an aluminum halide; is disclosed.