Abstract:
Disclosed is the observation that 7-aryl-quinone methides and 4-tert-butylcatechol, when used in combination in a vinyl aromatic monomer to inhibit polymerization,do not inhibit polymerization to the same extend as each would if used separately. Stated another way, a phenomenon has been observed that when these two compounds are used together, they can, to a large extent, render each other unable to inhibit polymerization in a vinyl aromatic monomer. Also disclosed are methods of preventing adverse results of this interaction when undesired and a method of using this interaction to prepare a reactive vinyl aromatic monomer having a concentration of 4-tert-butylcatechol that would otherwise inhibit polymerization. The invention is disclosed to be useful with the production and storage of any vinyl aromatic monomer and is disclosed to be particularly useful with the production and storage of styrene monomer.
Abstract:
Disclosed is a heterophasic polymer having a flowability over a broad range of xylene solubles content of the heterophasic polymer, a metallocene catalyst system (MCS) for producing such heterophasic polymer, and a method of producing such heterophasic polymer using the metallocene catalyst system. The MCS includes a support and a metallocene bound substantially throughout the support.
Abstract:
It has been discovered that certain nitrogen-containing thiols other than mercaptobenzothiazole (MBT) perform equivalently as accelerators in preparing asphalt polymer compositions. Typically, the crosslinker in these compositions is sulfur. Nitrogen-containing thiols containing at least one functional group —N═(SH)— have been found to be useful alternate accelerators along with activators such as zinc oxides. Particular nitrogen-containing thiols include, but are not necessarily limited to, 2-mercaptobenzoxazole (MBO), 2-mercapto-5-methyl-1,3,4-thiadiazole (MMTD), and combinations thereof.
Abstract:
An accelerated method of determining the failure time of a polyethylene resin by determining the minimum displacement rate, or the time at minimum displacement rate, using ASTM F 1473-01, then following one of these routes: (1) If failure has not yet occurred, cryogenically fracturing the resin specimen and examining it for slow crack growth to determine whether the anticipated, or desired, failure time is generally before or after the predicted failure time; or (2) Applying the minimum displacement rate, or the time at minimum displacement rate, in the appropriate mathematical formula to predict the failure time for the resin. The mathematical formula is derived from the discovery of a power law relationship between the failure time and minimum displacement rate, or between failure time and the time at minimum displacement rate. Thus, it is not necessary to actually test all the way to failure using ASTM F 1473-01, thereby accelerating testing capability and consequently enabling more rapid development of new resins.
Abstract translation:通过使用ASTM F 1473-01确定最小位移速率或最小位移速率的时间来确定聚乙烯树脂的故障时间的加速方法,然后遵循以下路线之一:(1)如果还没有发生故障 对树脂样品进行低温压裂并检查其是否有缓慢的裂纹扩展,以确定预期的或期望的故障时间是否通常在预测的故障时间之前或之后; 或(2)以适当的数学公式应用最小位移速率或最小位移速率时间来预测树脂的失效时间。 数学公式是从发现故障时间和最小位移速率之间的幂律关系,或者在故障时间与最小位移速率时间之间发现的。 因此,不需要使用ASTM F 1473-01实际测试所有的故障,从而加快了测试能力,从而可以更快速地开发新型树脂。
Abstract:
A new synthesis of a Ziegler-Natta catalyst uses a multi-step preparation that includes treating a magnesium dialkoxide compound with halogenating/titanating agents, an organoaluminum preactivating agent, and a heat treatment. The catalyst may be used in the polymerization of olefins, particularly ethylene, to control the molecular weight distribution of the resulting polyolefins.
Abstract:
A multilayer polyolefin film of the type suitable for packaging application in which heat seals are formed, and in its preparation the multilayer film comprises a flexible substrate layer formed of a crystalline thermoplastic polymer having an interface surface. A heat-sealable surface layer is bonded to the interface surface of the substrate layer and is formed of a syndiotactic propylene polymer effective to produce a heat seal with itself at a sealing temperature of less than 110° C. The surface layer has a thickness which is less than the thickness of the substrate layer. The heat-seal layer can be formed of syndiotactic polypropylene polymerized in the presence of a syndiospecific metallocene catalyst and having a melt flow index of less than 2 grams/10 minutes. The multilayer film can take the form of a biaxially-oriented film. In the production of the multilayer film incorporating a substrate layer and a heat-sealable surface layer, a crystalline thermoplastic polymer is extruded and formed into a substrate layer film. A second polymer comprising a syndiotactic propylene polymer which is effective to form a heat-sealable surface layer is extruded to form a surface layer that is bonded to the interface of the substrate layer at a temperature within the range of 150-260° C.
Abstract:
The alkylation of benzene-containing feedstock over a zeolite beta alkylation catalyst which is formulated with a silica binder and has an average regeneration coefficient of at least 95% for at least three regenerations. The alkylation reaction is carried out in the liquid phase or supercritical region with a C2-C4 alkylating agent, specifically ethylene. The catalyst exhibits a regeneration coefficient of at least 95% after ethylation of the benzene with ethylene at a benzene/ethylene mole ratio of less than 10. The ethylation of benzene occurs at an initial designated primary activity. The operation of the reaction zone is continued until the activity of the catalyst for the ethylation of benzene decreases by a value of at least 0.1% and not more 1% from the initial designated primary activity. The operation of the reaction for alkylation is terminated and a regeneration procedure is instituted in which the catalyst is regenerated in an oxidizing environment at an average temperature of no more than 500° C. At the conclusion of the regeneration procedure, the operation of the alkylation zone is reinstituted with the reaction zone again operated under conditions as described above followed by regeneration.
Abstract:
Disclosed is process for producing polyethylene using a slurry loop reactor. The process includes using a mathematical model to predict a plurality of process control parameters based on the desired product properties and reactor characteristics and controlling the process using the predicted process control parameters. Also disclosed is a process controller programmed with the model and a method for optimizing the configuration of a loop reactor using the model.
Abstract:
The present invention provides a dispersing agent that facilitates the delivery of a cross-linking agent to polymer modified asphalt. The present invention further includes a composition comprising a liquid hydrocarbon, the dispersant and cross-linking agent, and methods of preparing the composition and of preparing cross-linked polymer modified asphalt composition.
Abstract:
A system for pressurizing a propylene polymerization reactor includes: a pressurization vessel including an internal heat exchanger; a pressure sensor for monitoring the pressure in the vessel, the pressure sensor providing a signal indicative of the pressure in the vessel; a control valve for supplying heated gas to a first region of the vessel in response to signals from the pressure sensor, the first region of the vessel being maintained above the critical temperature and pressure of propylene; a temperature sensor for monitoring the temperature in a second region of the pressurization vessel, the temperature sensor providing a signal indicative of the temperature in the second region of the vessel; and a control valve for supplying a cooling medium to the internal heat exchanger to cool propylene in the second region below the critical temperature of propylene at the pressure in the pressurization vessel.