摘要:
A block copolymer of propylene is produced by using propylene itself as a liquid medium, conducting continuous polymerization (former-stage polymerization) of propylene alone or propylene and a small amount of ethylene at first and then conducting batchwise copolymerization (latter-stage polymerization) of ethylene and propylene. The amount of an activity improver to be added to a polymerization tank for the latter-stage polymerization and/or the polymerization time of the latter-stage polymerization are controlled in accordance with the amount of a slurry transferred from a polymerization tank for the former-stage polymerization to the polymerization tank for the latter-stage polymerization so as to maintain the ratio of the amount of the polymer polymerized by the former-stage polymerization to the amount of the polymer polymerized by the latter-stage polymerization constant in the block copolymer.
摘要:
Method of adding water and a hydroxide of an alkali metal or alkaline earth metal to a washing solvent such as an alkylamide and/or alkylsulfoxide when washing and removing high molecular substances stuck on the interior of a production apparatus or molding machine for an aromatic vinyl-acrylonitrile copolymer. A method for regenerating and recovering the washing solvent used for the above-mentioned washing and removal by means of an evaporator and distillation tower.
摘要:
Disclosed herein is a method for controlling the molecular weight of a propylene homo- or co-polymer at a constant level upon subjecting propylene alone or a mixture of propylene and another .alpha.-olefin copolymerizable with propylene as a monomer or monomer mixture to bulk polymerization in the presence of hydrogen as a molecular weight modifier in a reaction tank equipped with a reflux condenser. According to the present invention, it is possible to prepare continuously a propylene homo- or copolymer, the molecular weight of which is controlled at a desired level, by measuring moment by moment the quantity of heat removed from the reaction tank, calculating the amount of the monomer or monomer mixture polymerized in the reaction tank based on the thus-calculated quantity, determining in advance the relationship between molecular weights and the volumes of hydrogen consumption required per unit amounts of corresponding polypropylene homo- or co-polymers, calculating the volume of hydrogen which is to be introduced into the reaction tank so as to obtain polypropylene of a desired molecular weight from the above relationship and the above-calculated polymerized amount, and charging hydrogen into the reaction tank in accordance with the above-calculated volume of hydrogen which varies from time to time.
摘要:
A propylene-ethylene block copolymer is produced by continuous bulk polymerization in which propylene alone is polymerized or propylene and ethylene are copolymerized at the ethylene/propylene reaction ratio of 6/94 using propylene as a liquid medium, and subsequently by batch-wise copolymerization in which propylene and ethylene are copolymerized at the ethylene/propylene reaction ratio from 85/15 to 5/95.
摘要:
A syndiotactic polypropylene copolymer is disclosed which comprises 70 to 99.9 mole % of propylene and 0.1 to 30 mole % of an olefin other than propylene; in the 13C-NMR spectrum of the syndiotactic polypropylene copolymer, a ratio of the intensity of a peak at about 20.2 ppm to the sum of the intensities of the total peaks attributable to methyl groups in propylene units at about 19-22 ppm being 0.3 or more. Also disclosed are extrusion-molded high-transparency articles, especially films and sheets and blown films, obtained by the extrusion of a polypropylene substantially having a syndiotactic structure.
摘要:
A fiber excellent in strength and having an average size of 10,000-0.1 denier can be obtained by extruding a raw material composed mainly of a polypropylene having a syndiotactic pentad fraction of 0.7 or more and optionally stretching the resulting extruded material.By using as the raw material a composition consisting of two kinds of polypropylenes each having an intrinsic viscosity .eta..sub.1 or .eta..sub.2, the log(.eta..sub.2 /.eta..sub.1) being more than 0.05 or less than -0.05, and a syndiotactic pentad fraction of 0.7 or more at a weight ratio of 95:5-5:95 or a composition consisting of at least 50 parts by weight of a syndiotactic polypropylene having the intrinsic viscosity .eta..sub.1 and a syndiotactic pentad fraction of 0.7 or above and at most 50 parts by weight of an isotactic polypropylene having the intrinsic viscosity .eta..sub.2, the extrudability is improved and the fiber stretching conditions are broadened.
摘要翻译:通过将主要由间同立构五单元组分为0.7以上的聚丙烯组成的原料挤出并任选地拉伸所得的挤出材料,可以获得强度优异且平均粒径为10,000-0.1旦尼尔的纤维。 通过使用由两种各自具有特性粘度eta 1或eta 2的聚丙烯组成的组合物,log(eta 2 / eta 1)大于0.05或小于-0.05,并且间同立构五单元组分数 0.7重量%以上,重量比为95:5.5:95的组合物或由至少50重量份的特性粘度η1和间同立构五单元组分数为0.7以上至多50份的间同立构聚丙烯组成的组合物 的特性粘度等于2的全同立构聚丙烯,可挤出性提高,纤维拉伸条件变宽。
摘要:
A process is provided herein wherein a solid polymer slurry diluted with a specific diluent is continuously discharged under controlled conditions from a high pressure zone to a low pressure zone substantially maintained at atmospheric pressure and the slurry is then separated into said diluent and dried polymer, the improvement wherein the discharged amount of the solid polymer slurry is strictly controlled by varying the heat in the second zone and simultaneously adding a diluent which is gaseous under normal temperature and pressure so that by the control of these two perimeters a continuous slurry discharge can be maintained at predetermined levels.
摘要:
Disclosed herein is a polypropylene resin composition of a high syndiotacticity comprising a substantial homopolymer of propylene, in which the ratio of the intensity of the peak attributable to the syndiotactic pentad bonds to the sum of the intensities of all the peaks attributable to the methyl groups in the spectrum of the methyl groups measured by .sup.13 C-NMR is 0.7 or more, and a copolymer of ethylene and propylene, and a preparation process thereof.
摘要:
Copolymers of butene-1 and propylene, having specific physical properties and substantially a syndiotactic structure; and easily heat-sealable polypropylene resin compositions comprising 5-50 parts by weight of one of the copolymers and 95-50 parts by weight of a stereoregular crystalline propylene-ethylene copolymer or propylene ethylene-C.sub.4-12 -.alpha.-olefin copolymer having specific compositions and melt flow index.
摘要:
According to the present invention, molded articles can be provided in which a melting point attributed to a syndiotactic polypropylene and measured at a temperature rise rate of 10.degree. C./minute by differential scanning thermal analysis is indicated by a substantially single peak, the aforesaid molded articles being obtained by heating, melting and molding a substantially syndiotactic homopolymer of propylene, a substantially syndiotactic copolymer of propylene and a small amount of another olefin, or a mixture of these polymers and a small amount of a substantially isotactic polypropylene, and then subjecting the molded products to a heat treatment. Furthermore, a method for preparing the above-mentioned molded articles is also provided. The molded articles have high stiffness and impact resistance.