摘要:
The present invention relates to a method for preparation a glycolide polyester by ring opening polymerization characterized in that glycolide monomer with optional co-monomer(s) of cyclic ester(s) is/are subjected to ring opening polymerization in the presence of a dispersion stabilizer and a catalyst, said catalyst being selected for precipitating glycolide homopolymer or copolymer from solvent, said solvent being selected so that the glycolide monomer and the optional co-monomer(s), the dispersion stabilizer and the catalyst are soluble therein but said glycolide homopolymer or copolymer is non-soluble. The present invention further relates to an in situ ring opening polymerizing process product, and to use of said glycolide polyester, and to further processing of said glycolide polyester.
摘要:
The invention relates to a method for preparing a thermoplastic coating on a substrate from a hemicellulose polymer or a cellulose polymer wherein the method comprises at least following steps: —providing a cellulose polymer or a hemicellulose polymer having at least one hydroxyl group which can be used for forming cellulose or hemicellulose ester, —reacting hemicellulose polymer or cellulose polymer with a residue originating to fatty acid with an aliphatic carbon tail of 4-28 carbons or ester thereof, for obtaining hemicellulose fatty acid ester or cellulose fatty acid ester, —dispersing the hemicellulose fatty acid ester or cellulose fatty acid ester into aqueous solution, —dispersion coating a substrate with dispersed hemicellulose fatty acid ester or cellulose fatty acid ester for preparing a coated substrate and —heating the coated substrate for preparing a substrate provided with a coating, so that the substrate provided with a coating is heat-sealable with the same substrate provided with said coating or with an uncoated substrate.
摘要:
A process for treating cellulosic fibres comprises mechanically pre-treating the fibres followed by treating the fibres with an enzyme and thereafter mixing the fibres with a solution comprising an alkali metal hydroxide followed by mechanically treating the fibres to form microfibrillated cellulose. In this way it is possible to produce microfibrillated cellulose (MFC) in an improved and energy efficient way.
摘要:
The invention relates to barrier products and a method for the manufacture thereof. The product comprises a fibrous substrate, a coating layer on at least one surface of the fibrous substrate, and a barrier applied on the coating layer, comprising a thin film with a thickness of less than about 1 micrometer and capable of providing barrier properties to the fibrous product. According to the invention, the coating layer comprises biopolymer, which have been found to be suitable for atomic layer deposition of thin barrier films comprising e.g. metal oxide. Improved oxygen, water vapour and aroma barrier properties can be achieved by the invention for papers and paperboards for packaging purposes.
摘要:
A process for producing polyethylene compositions in the presence of a catalytic system of ethylene polymerizing catalyst and cocatalyst in a multistage continuous reaction sequence consisting of successive liquid phase and gas phase polymerizations is disclosed. In the first step of the process, ethylene and optionally hydrogen and comonomer are polymerized in a first loop reactor in a low boiling hydrocarbon medium in the presence of ethylene polymerizing catalyst and cocatalyst. The reaction mixture is then removed and then transferred to a second loop reactor where polymerization is continued by addiing ethylene, hydrogen and optionally inert hydrocarbon, comonomers and cocatalysts. Thereafter, the reaction mixture is removed from the second loop reactor along with an essential part of the reaction medium and transferred to a gas phase reactor where polymerizing is continued in the presence of added ethylene and optionally hydrogen, comonomers and cocatalysts to form an end product. The residence time and reaction temperature being such that the proportion of the ethylene polymer produced in the first loop reactor to the end product of the process is between 1-20%.
摘要:
A method for preparing a specific product from a polysaccharide in which at least one hydroxyl of a saccharide unit is substituted with an ether or ester moiety. The ether or ester moiety is provided with ethenyl and/or epoxy functionality for preparing an activatable polysaccharide polymer and the activatable polysaccharide polymer with ethenyl and/or epoxy functionality is optionally reacted with an additional coupling reagent, having at least two coupling functionality for preparing polysaccharide polymer with additional activatable crosslinker. Thereafter, the activatable polysaccharide polymer or the polysaccharide polymer with an additional activatable crosslinker, is activated for crosslinking the polysaccharide polymer with another polysaccharide polymer by reacting the activatable polysaccharide polymer or polysaccharide polymer with an additional activatable crosslinker with a crosslinking initiator for crosslinking the polysaccharide polymer chains with each other, for preparing a product such as hydrogel, film, coating or membrane with polysaccharide backbone.
摘要:
The invention relates to a method of producing olefinic monomers for the production of a polymer. The invention particularly relates to the production of tall oil-based biopolymers, such as polyolefins. In the stages of the method bio oil, with a content of over 50% of fatty acids of tall oil and no more than 25% of resin acids of tall oil, and hydrogen gas are fed into a catalyst bed (7); the oil is catalytically deoxygenated in the bed by hydrogen; the flow exiting the bed is cooled down and divided into a hydrocarbon-bearing liquid phase (10) and a gas phase; and the hydrocarbon-bearing liquid (13) is subjected to steam cracking (4) to provide a product containing polymerizing olefins. The deoxygenation in the bed can be followed by a catalytic cracking or, with a suitable catalyst, the deoxygenation and cracking can be simultaneous. The separated hydrogen-bearing gas phase can be circulated in the process.
摘要:
The invention relates to a flexible and porous fabric structure comprising a support structure (1) and a coating material for use in a paper machine. The coating material (2) is arranged solely on the surface of the support structure (1) at a predefined location(s) so that the coating material (2) does not substantially alter the permeability properties of the support structure (1). The invention also relates to a method for manufacturing a fabric structure.
摘要:
An arrangement in connection with clamping tools, which comprises a nozzle structure which consists of coaxially arranged nozzle elements and is arranged to form one or more layers which cover a flexible elongated element on the surface of the flexible elongated element, which passes through the innermost nozzle element, in which arrangement at least the head of the nozzle element, which controls the flexible elongated element, is a separate unit which is arranged to be pushed into its position in the direction of the flexible elongated element and provided with gripping means, which grip the innermost nozzle element of the nozzle structure as the unit arrives at the nozzle element. The joint between the separate unit and the nozzle element of the nozzle structure is arranged to be loosened by repulsive force acting on the separate unit in the direction of the flexible elongated element and the separate unit is arranged to exit from the nozzle structure in the direction of the flexible elongated element.
摘要:
The present invention concerns a method and an apparatus of introducing polymer slurry obtained from a slurry reactor into a gas phase reactor containing a fluidized bed (C, D). According to the present invention, the content of the slurry reactor (R1) is conducted directly to the fluidized bed reactor (R2) as a multiphase stream comprising polymer, active catalyst and reaction medium using at least one feed line (10; 11; 12), and the stream is fed below a first fluidized zone (C) of the gas phase reactor via inlet pipe protruding into the fluidized bed in order to increase the once-through conversion of the process. By means of the invention, the amount of unreacted monomers which needs to be recirculated is minimized and investment and operation costs of the recovery section are greatly reduced.