摘要:
A catalyst component useful in the polymerization of olefins which includes a support formed of a copolymer of an olefin and a silane monomer having at least one unsaturated hydrocaryl substitutent. A process for making the catalyst component as well as a catalyst composition which includes the catalyst component is also set forth.
摘要:
Adhesive blends having special utility in the formation of composite structures with LDPE, EVOH, and impact-modified polystyrene comprise a mixture of an ethylene/ester copolymer such as EVA, polystyrene, such as impact-modified polystyrene, and a functionalized SEBS block copolymer.
摘要:
An improved gas-phase copolymerization process for producing copolymers of propylene and ethylene in multiple reactors using high activity Ti/Al catalysts is provided. The improvement consists of developing a control parameter derived from eight integral regions of the copolymer .sup.13 C NMR spectrum, defining the limits of the control parameter for the process, and operating the process to maintain the parameter within the defined limits. This is accomplished by adjusting the amount of ethylene in the primary and/or secondary reactor and adjusting other process variables as required.
摘要:
The present invention is directed to a supported tungsten-based catalyst composition useful for the dimerization of alpha-olefins including ethylene. More particularly, the catalyst composition of the instant invention comprises an organic or inorganic support material that is contacted with a tungsten salt and an organic amine compound.
摘要:
A catalyst component useful in the polymerization of olefins is disclosed. The catalyst component comprises the product obtained by steps of (a) contacting silica with at least one hydrocarbon soluble magnesium-containing compound; (b) contacting the product of step (a) with component (1), a heterocyclic fused ring compound substituted with at least one oxygen atom, and component (2), a modifying compound selected from the group consisting of silicon halides, boron halides, aluminum halides, alkyl silicon halides and mixtures thereof, with the proviso that components (1) and (2) be present such that the molar ratio of component (2) to component (1) is at least about 4:1; and (c) contacting the product of step (b) with a titanium-containing compound having the structural formula TiX.sub.m (OR).sub.n, where X is halogen; R is hydrocarbyl; m is an integer of 1 to 4; and n is 0 or an integer of 1 to 3 with the proviso that the sum of m and n is 4. A catalyst system, used in the polymerization of alpha-olefins, which comprises the catalyst component of this disclosure, an aluminum-containing compound and a silane compound is also taught. Finally, a process for the polymerization of alpha-olefins, utilizing the catalyst system of the present disclosure, is described.
摘要:
A stationary plate assembly for a rheometer that selectively provides steady state and dynamic testing of melt viscoelastic characteristics of a material sample. The stationary plate assembly has a stationary sample plate magnetically coupled to its supporting member. Therefore, after the steady state testing is complete, the movable plate, material sample and stationary plate may be moved vertically away from the stationary plate supporting member. Therefore, any spurious, erratic rotations of the movable plate when the rheometer is switched form the steady state test mode to the dynamic test mode will not cause a further working of the material sample.
摘要:
Improved two-component blends which exhibit good adhesion to 4-methylpentene-1 polymers and vinyl alcohol polymers and which may be used as an adhesive interlayer when laminating layers of the polymers are provided. Ethylene-alkyl acrylate copolymers, preferably ethylene n-butyl acrylate copolymers, and modified propylene polymers, preferably maleic anhydride grafted statistical propylene-ethylene copolymers and propylene-ethylene impact copolymers, are combined to obtain the blends of the invention. Useful laminated structures comprised of a layer of poly-4-methylpentene-1 homopolymer or copolymer, a layer of the adhesive blend and a layer of ethylene-vinyl alcohol copolymer with one or more optional layers, such as a paperboard, are also disclosed.
摘要:
A process for making a biodegradable aliphatic polyester and the polyester so formed is disclosed. The process comprises copolymerizing a cyclic ketene acetal having the structural formula ##STR1## where R is a bivalent moiety, and an olefin. This copolymerization occurs in a solution of a tertiary alcohol and in the presence of a free radical initiating effective amount of a compound having the structural formula ##STR2## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are the same or different and are C.sub.1 -C.sub.20 hydrocarbyl, C.sub.1 -C.sub.20 hydrocarbyloxy, cyano, halogen, carboxy, carboalkoxy, carbonyl or formyl. The copolymerization occurs at a temperature in the range of between in excess of ambient temperature and less than 100.degree. C. and at a pressure in excess of about 2,000 psi. The aliphatic polyester product of this process contains repeating structural units of the formula ##STR3## where A is a radical of a polymerized olefinic monomer; R is a bivalent moiety; x is a positive integer; and y and z are 0 or a positive integer with the proviso that the sum of y and z is at least 1, ratio of x to y is in the range of between about 3:1 and about 200,000:1, the ratio of z to y is in the range of between 0 and about 0.5:1; and said polyester has a weight average molecular weight of at least about 40,000.
摘要:
The present invention is directed to improved microfine propylene polymer powders having reduced fines which are comprised of spherical or substantially spherical particles and have a number average particle size from about 25 to about 60. A process for preparing the improved powders is also provided. The process involves dispersing a molten propylene homopolymer or copolymer which has been visbroken in a liquid medium in the presence of a nonionic surfactant, cooling the dispersion below the melt point of the propylene polymer and recovering the powder.
摘要:
A novel catalyst support and a method for preparation thereof, characterized by the presence of selected amounts of a hydrocarbon soluble magnesium-containing compound applied to the support relative to solvent, wherein a surface uniformly and essentially continuously moistened with the solvated magnesium compound is achieved in a condition of incipient precipitation to permit the formation of a regular essentially continuous distribution of the magnesium compound onto and conforming to the support material The drying process under these conditions is effective in maintaining to a high degree the effective surface area and pore volume of the material. The support containing the adsorbed magnesium is then dried in a controlled manner to essential incipient wetness conditions providing a regular spatial distribution of stacked reticular magnesium values at a level of one to five molecular monolayers on the support.A representative process for polymerizing or copolymerizing olefins providing stereospecific polymers such as propylene is disclosed.