摘要:
Apparatus and method for grinding levelling of paper, cardboard or a similar continuous web manufactured from vegetative based fibrous raw-material, said apparatus comprising a plurality of grinding means such as rolls or belts preferably arranged on both sides of the web, said means being deviated from the moving direction of the web or the web being deviated from these by means of squeeze rolls and which rolls are characterised by being trioelectrically charged with a similar electrical charge as the ground surface. The web tension can be regulated by moving the grinding means or the web from its direction of movement and the dust generated at the grinding is removed by a vacuum system.
摘要:
The invention concerns a method and a grouting composition for filling cracks in stone and concrete structures. According to the method, the cracks are filled with a composition containing a binder which achieves setting of the composition under the influence of water, whereby the cracks are filled. The grout contains a latent hydraulic binder, an alkaline component for activating the binder, additives and aggregate having a particle size of less than 1.6 mm. The grout is easily formulated to a suitable viscosity determined by the intended use by varying the relative amounts of binder, activator and aggregate. The grouting composition has good anti-wash-out properties, enabling its use for filling even cracks where strong water flow occurs.
摘要:
The present invention concerns a polymer composition and films manufactured from such compositions. The present polymer compositions comprise 80-99 wt.% on an essentially linear polyethylene with a component having a relatively low MW and a relatively high density, and another component having a relatively high MW and a relatively low density, said linear polyethylene having an MFR21 of at least 5 g/10 min, a maximum MFR2 of 6 g/10 min, a density of 915-945 kg/m3. Further the compositions contain 1-20 wt.% of a branched copolymer of ethylene and an acrylate monomer with 20-28 wt.% acrylate monomer units. The MFR¿2? of the copolymer is 0.4 to 2.0 g/10 min. Cross-laminated film materials having good mechanical properties can be manufactured from the present compositions.
摘要:
The present invention concerns a process for producing homogeneous polyethylene compositions and processes for making high density, medium density and low density films therefrom. The process comprises carrying out the polymerization in the presence of an ethylene-polymerizing catalyst system in a multistage reaction sequence of successive polymerization stages, at least one of which is a loop polymerization stage, and at least one of which is a gas phase polymerization stage. According to the invention, said loop polymerization stage is operated using a diluent selected from the group of linear and branched C4-C6 hydrocarbons and/or mixtures thereof. The reactor sequence is operated with different amounts of hydrogen and comonomers to produce a high molecular weight portion in one of the polymerization stages and a low molecular weight portion in another, so as to provide bimodal polyethylene composition with a low molecular weight part having an MFR2 of 250 g/10 min or more. The obtained material is homogenous and the fines level in the process is low.
摘要:
The invention provides a method for the removal of biological species, such as Cryptosporidium, from water using aluminium based media which contains surface A1-OH groups.
摘要:
The invention is related to a method for forming calcium carbonate. In the method, calcium oxide is reacted with carbonate ions in the presence of water to produce calcium carbonate. According to the invention, the formation is carried out directly from calcium oxide to calcium carbonate without intermediate stages in a three-phase precipitation, whereby the hydration of the calcium oxide to calcium hydroxide and the carbonation of the hydrated part are carried out immediately after one another under so intensive agitation that the calcium carbonate elements thus created are detached from the surface of the calcium hydroxide. The mixing is preferably carried out in a fluid medium where the amount of gaseous phase is at least 20 parts by volume and the amount of liquid phase is 0.5 to 1 part per one part by volume of the solid matter of the suspension. In the process, the desired end product, PCC, can be prepared in a very short residence time and with a small operational content.
摘要:
The invention relates to process for dimerizing olefinic hydrocarbon feedstock, to hydrocarbon compositions and to fuel components produced by the process. According to the invention, fresh olefinic hydrocarbon feedstock is fed to a reaction zone of a system including at least one reaction zone and at least one distillation zone. The olefinic hydrocarbon feedstock is contacted with an acidic catalyst in the presence of an oxygenate at conditions in which at least a part of the olefins dimerizes. The effluent from the reaction zone is conducted to the distillation zone where dimerized reaction product is separated from effluent, and at least one flow comprising oxygenate is withdrawn from the side of at least one distillation column. The flow is circulated from distillation zone back to dimerization. The reaction mixture is recovered and optionally hydrogenated to form a parafinic reaction product.
摘要:
Described herein is a process and an apparatus for polymerizing propylene. The process comprises carrying out the polymerization in at least one slurry reactor and at least one gas phase reactor without recycling unreacted monomers to the slurry reactor. A polymerization product containing unreacted monomers is recovered from the slurry reactor and volatile components are separated from the product in a separation unit. The polymerization product is recovered from the separation unit and conducted to a first gas phase reactor; and at least a part of the volatile components are recovered from the separation unit and conducted them to a gas phase reactor. At least 10 % of the polymer product is produced in the gas phase reactor(s). The invention provides propylene homopolymers and alloys of propylene homopolymers and copolymers having good impact and creep properties.
摘要:
The present invention relates to the use of calcium oxalate as a filler or pigment. In particular described herein is a method of reducing the combustion residue of coated paper or cardboard products by replacing at least a part of the conventional pigments and filler needed for achieving predetermined optical properties with calcium oxalate.