54results about How to "Oligomer content" patented technology

The present disclosure provides a Ziegler-Natta catalyst composition comprising a procatalyst, a cocatalyst and a mixed external electron donor comprising a first selectivity control agent, a second selectivity control agent and an activity limiting agent. A polymerization process incorporating the present catalyst composition produces a high-stiffness propylene-based polymer with a melt flow rate greater than about 50 g/ 10 min. The polymerization process occurs in a single reactor, utilizing standard hydrogen concentration with no visbreaking.

The invention relates to a polyester with low oligomer content and a preparation method of the polyester. The method comprises the following steps: carrying out an esterification reaction and a first-stage condensation polymerization reaction on M and dihydric alcohol in the presence of a catalyst A; carrying out a second-stage condensation polymerization reaction; adding a catalyst B and carryingout a third-stage condensation polymerization reaction; and finally, adding a chain extender for carrying out a chain extension reaction, thereby obtaining the polyester with low oligomer content, wherein M is dicarboxylic acid or binary alkyl carboxylate; the catalyst A is a titanium catalyst, an antimony catalyst or metal acetate, the catalyst B is more than one of aluminum isopropoxide, dibutyl tin oxide, monobutyltin oxide, stannous octoate and stannous 2-ethyl caproate, and the oligomer content in the prepared polyester is less than 1.5wt%. The method disclosed by the invention is simplein operation, and the prepared product is low in oligomer content and has excellent popularization value.

The present invention discloses one kind of linear phenolic resin with narrow molecular weight distribution and its preparation process. The linear phenolic resin is prepared with phenols and aldehydes under the action of composite catalyst including acid and layer silicate. It has the features of low oligomer content and narrow molecular weight distribution, and may be applied as the adhesive for Bakelite, friction material, grinding tool, etc.

The invention relates to a catalyst component and catalyst for olefin polymerization, and preparation methods thereof. The catalyst component comprises 1) an ultrafine inorganic oxide carrier and 2) a reaction product of magnesium halide, halogenated hydrocarbon, titanium halide and an electron donor compound. The catalyst comprises a reaction product of the following components: (A) the catalyst component provided by the invention, and (B) an organo-aluminum compound with a general formula of AlR<n>X<3-n>, wherein in the formula, R is an alkyl group with a hydrogen or carbon atom number of 1 to 20, X is halogen, preferably chlorine, bromine or iodine, and n is more than 0 and no more than 3. The catalyst has high activity; and a polymer prepared by using the catalyst has higher bulk density and a higher melt index.

The invention discloses a novel ethylene oligomerization catalyst system with high activity and high selectivity as well as a preparation method and application thereof. The catalyst system comprisesa novel PNP ligand, a transition metal compound and a cocatalyst, according to the PNP ligand, a binary ring-fused aromatic group is used for replacing phenyl in a conventional PNP ligand, and the binary ring-fused aromatic substituent has more substitution positions, richer aromatic ring electron cloud distribution modes and larger space volume than a benzene ring, so that more and stronger influences can be provided for a donor part of the ligand, and therefore, the catalyst shows more excellent linear alpha-olefin (LAO) selectivity in an ethylene oligomerization reaction, and 1-hexene or 1-octene can be prepared with high selectivity.

The invention discloses a pretreatment method for rectifying and recovering dimethyl formamide (DMF) waste liquid of polyurethane (PU) synthetic leather. The pretreatment method comprises the following steps: (1) pumping the DMF waste liquid from a waste water storage tank of a PU synthetic leather production line into a coarse filter consisting of a stainless steel filter screen by using an infusion pump and performing first-stage separation to obtain coarse filtration DMF waste liquid; and (2) allowing the coarse filtration DMF waste liquid obtained by first-stage separation to enter a microfiltration hollow fiber membrane separation device and performing second-stage separation to obtain a DMF fine solution for rectification and recovery. By the pretreatment method for rectifying and recovering the DMF waste liquid of the PU synthetic leather provided by the invention, the problems of high pollution and high energy consumption of rectification and recovery of the DMF waste liquid in the PU synthetic leather industry are solved; the aims of energy saving and emission reduction in the production process of the PU synthetic leather are fulfilled, and economic benefit, social benefit and environmental benefit are organically unified.

The present invention relates to an ethylene-alpha-olefin copolymer and a manufacturing method thereof, and applications of the ethylene-alpha-olefin copolymer in molding product manufacturing, wherein the ethylene-alpha-olefin copolymer exhibits balanced and excellent processability and mechanical properties compared with the ethylene-alpha-olefin copolymer in the prior art.

The present application provides a novel catalyst for olefin polymerization. The catalyst comprises a magnesium-containing composite carrier, a dispersant Ti(OBu)4, a pyrrole ring-containing electron donor compound and active components VCl4 and TiCl4. The magnesium-containing composite carrier of the the catalyst is obtained by spray-drying, has a preferable shape and high ethylene polymerization activity, and is suitable for being used in a gas-phase fluidized bed polymerization process, and is further suitable for being used in a slurry polymerization process; linear polyethylene containing relatively few oligomers with bimodal or wide relative molecular weight distribution can be prepared, and the obtained linear polyethylene has a good material property. The polyethylene resin prepared by using the catalyst has bimodal or broad relative molecular mass distribution, polyethylene resin containing relatively few oligomers can be obtained when polymerization of ethylene and comonomer is catalyzed, a film material blown by the resin has a preferable material property, a good strength and a high dart drop impact quality.

The invention relates to homogeneous hyper-viscous polyester and a preparation method thereof. The method comprises the following steps of: controlling the mechanism of adding a catalyst during a synthesis process to obtain low-viscous polyester with an intrinsic viscosity of 0.300-0.500 dL/g, and then performing solid phase thickening on the low-viscous polyester to obtain the homogeneous hyper-viscous polyester with an intrinsic viscosity of 0.85-1. 15dL/g, an intrinsic viscosity deviation less than or equal to 0.02dL/g and a molecular weight distribution index of 2.5, wherein the catalyst is added when the average polymerization degree of an intermediate product in a polymerization reaction reaches 8-17; the pre-reaction of the solid-phase thickening is divided into four stages which are a first stage, a second stage, a third stage, and a fourth stage, the corresponding temperatures are 190-195 DEG C,195-210 DEG C, 210-220 DEG C and 220-230 DEG C respectively. The preparation methodof the homogeneous hyper-viscous polyester obviously reduces the content of oligomer in a product, and the prepared polyester has high quality and excellent popularization value.

The invention discloses a polyurethane adhesive with low stripping force, the polyurethane adhesive comprises a polyurethane adhesive main agent, a curing agent and an auxiliary additive, the polyurethane adhesive main agent is a hydroxyl (-OH) terminated prepolymer obtained by monomer modified polyol; the curing agent is an isocyanate group (-NCO) terminated prepolymer obtained by reacting diisocyanate with polyhydric alcohol; monoamino fluorine-containing polyhedral oligomeric silsesquioxane (POSS) is introduced, and POSS is used for reducing the stripping force of the polyurethane adhesive;the auxiliary additive is composed of a catalyst, an antifoaming agent, an antistatic agent, an antioxidant and a chain extender; the polyurethane adhesive main agent, the curing agent and the auxiliary additive are mixed according to a certain ratio and uniformly stirred and then the mixture is used for coating to form a film; and the prepared adhesive film has the advantages of high exhaust speed, small stripping force, no bubbles after aging, no white spots, high temperature resistance, no residual adhesive and yellowing resistance, and good antistatic performance and the like.

The present invention has the effects of providing a thermoplastic resin composition, a method for preparing the thermoplastic resin composition, and a molded article comprising the thermoplastic resin composition, the thermoplastic resin composition comprising: a styrene-based copolymer containing a (meth) acrylate-based monomer, an aromatic vinyl-based monomer, and a maleimide-based monomer; a first graft copolymer comprising an acrylic rubber polymer, an aromatic vinyl-based monomer, and a vinyl nitrile-based monomer; and a second graft copolymer containing an acrylic rubber polymer, an aromatic vinyl monomer, and a vinyl nitrile monomer, in which the content of residual oligomers in the styrene copolymer is 0.37 wt% or less, and the content of residual oligomers in the styrene copolymer is 0.37 wt% or less. The acrylic rubber polymer of the first graft copolymer and the acrylic rubber polymer of the second graft copolymer have different average particle sizes.