6results about How to "Improve copolymerization performance" patented technology

The present invention provides a modified polyolefin resin that can form a coating that exhibits excellent adhesion to a low-polarity base material, especially a poorly adherable polyolefin base material with no surface treatment even when being dried at low temperatures and has flexibility (bendability). Provided is a modified polyolefin resin that is a modified product of a polyolefin resin having a melting point (Tm) by a differential scanning calorimeter (DSC) of 60 to 165°C with a modifier comprising the following (A): (A) a monomer mixture comprising Monomer Group (A-1) and Monomer Group (A-2) with a weight ratio of Monomer Group (A-1) to Monomer Group (A-2) ((A-1) / (A-2)) of 30 / 70 to 50 / 50.

This invention relates to the field of olefin polymerization and discloses an ethylene-enol copolymer and its preparation method. The preparation method of the ethylene-enol copolymer provided by this invention includes: using a catalyst composition to copolymerize ethylene and an enol, wherein the catalyst composition includes a) a monometallic compound and b) a cocatalyst component. According to the preparation method of the ethylene-enol copolymer of this invention, it exhibits excellent copolymerization catalytic activity and good copolymerization performance even at high temperatures, and has a high comonomer content, resulting in a high molecular weight ethylene-enol copolymer.

The invention relates to the technical field of preparation of functional regenerated polyester, and provides a preparation method of copolymerized flame-retardant regenerated polyester chips and fibers suitable for a regenerated polyester system, which comprises the following steps: by taking high-purity rBHET recovered by a chemical method as a raw material, introducing a reaction type organic phosphine flame retardant; reaction materials and reaction conditions in a temperature rise stage and a polycondensation stage of a polymerization process are regulated and controlled, a flame-retardant esterification liquid preparation process is not needed, flame-retardant regenerated polyester chips are prepared through direct copolymerization, and the flame-retardant regenerated polyester fibers are prepared through further melt spinning. The preparation process of the flame-retardant regenerated polyester chip is optimized, the thermal decomposition risk of the flame retardant in the preparation process is reduced, meanwhile, the hue, viscosity, flame retardance, processing stability and other properties of the flame-retardant regenerated polyester product are greatly improved, and the preparation method is suitable for industrial production of the flame-retardant regenerated polyester fiber.

The invention discloses a preparation method of a supported metallocene catalyst for ethylene polymerization. The preparation method comprises the following steps: carrying out thermal activation treatment on a silica gel carrier; modifying the thermally activated silica gel carrier by using alkyl tin chloride to obtain an alkyl tin chloride / silica gel carrier; modifying the alkyl tin chloride / silica gel carrier by using methylaluminoxane to obtain an alkyl tin chloride / methylaluminoxane / silica gel carrier; and then loading a metallocene compound to obtain the loaded metallocene catalyst. Alkyl tin chloride is used for modifying a silica gel carrier, the compound can react with hydroxyl, and a large amount of hydroxyl is eliminated; and the metallocene can be combined with MAO, so that certain space barrier exists between the MAO and the surface of the silica gel, the crowding effect is weakened, the loading capacity is improved, and metallocene combination sites are increased.

The invention relates to the field of polymers, and discloses an ethylene propylene diene monomer and a preparation method and application thereof, the content of a third monomer of the ethylene propylene diene monomer is greater than or equal to 7.9 wt%, and the third monomer is non-conjugated diene. The ethylene propylene diene monomer provided by the invention is relatively high in content of a third monomer, and the content of the third monomer can be up to 12.9 wt%.

This invention discloses a metallocene catalyst, its preparation method, and its application, belonging to the field of polyolefin catalyst technology. The catalyst consists of a coarse-porous silica support modified with norbornene / perfluoroalkyl dual-modification, a methylaluminoxane co-catalyst, and a diphenylmethylene(cyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconia dichloride metallocene compound. The silica support is chemically modified with norbornene triethoxysilane to introduce a norbornene functional group containing strained double bonds; then, through an olefin cross-metathesis reaction, perfluoroolefins are grafted onto the norbornene double bonds to form a "silica-norbornene-perfluoroalkyl" composite structure. This composite structure not only provides stronger physical confinement and chemical shielding effects, but its rigid norbornene bridging structure can also effectively suppress the structural collapse of mesoporous channels under high-temperature polymerization conditions, significantly improving the catalyst's activity lifetime and kinetic stability in the high-temperature environment of gas-phase polymerization.