Abstract: A press cover contains at least one polymer layer in which a reinforcing structure is embedded. The reinforcing structure contains at least one reinforcing thread, wherein the material of the reinforcing structure and that of the at least one polymer layer are selected such that the visible light transmittances thereof differ from each other.

Abstract: A press cover or jacket includes at least a first and a second polymer layer. The first polymer layer is a radially outermost polymer layer as seen relative to the longitudinal axis of the press cover and has a thickness that is at most 60% of the overall thickness of the press cover as seen in the radial direction of the press cover. The first polymer layer includes grooves or holes which are incorporated in the radially outermost lateral surface thereof and the depth of the grooves or holes, as seen in the radial direction of the press cover, have a depth that corresponds at most to 95% of the thickness of the first polymer layer. A press roll, a shoe press and a method of using a press cover are also provided.

Abstract: The invention relates to a press jacket comprising at least one polymer layer, where the polymer layer comprises, or has been produced from, a polyurethane, where the polyurethane has been formed from a prepolymer and a crosslinking agent, and the prepolymer is a reaction product of phenylene 1,4-diisocyanate and of a polyol, where the crosslinking agent comprises the following components: a first component comprising 1,4-butanediol or 1,4-hydroquinone bis(2-hydroxyethyl) ether (HQEE), a second component comprising at least one aliphatic diamine, a third component comprising at least one alkanolamine.

Abstract: A press cover or jacket includes at least one first polymer layer. The polymer layer contains or has been produced from a polyurethane, and the polyurethane has been formed from a prepolymer and a crosslinker. The prepolymer is a reaction product of naphthalene 1,5-diisocyanate or phenylene 1,4-diisocyanate and at least one polyol selected from a polycarbonate polyol, a polytetramethylene ether glycol, polyether polycarbonate polyol or mixtures thereof. A press using the press cover is also provided.

Abstract: A method produces or machines a roller which is suitable to be used in a machine for producing or processing a fibrous web. The roller contains a roller core and at least one functional layer. The method is characterized in that the method includes the application of a functional layer. The application of the functional layer is performed by applying a coating substrate to the surface of a roller core. The application takes place simultaneously over at least half the roller width, preferably over 75% of the roller width, particularly preferably over the entire roller width. The entire applied coating substrate or parts thereof are hardened, forming a solidified structure.

Abstract: A press jacket includes at least one polymer layer. The polymer layer includes, or has been produced from, a polyurethane. The polyurethane has been formed from a prepolymer and a cross linking agent. The prepolymer is a reaction product of phenylene 1,4-diisocyanate and a polyol. The cross linking agent includes the following components: a first component including 1,4-butanediol or 1,4-hydroquinone bis(2-hydroxyethyl) ether (HQEE), a second component including at least one aliphatic diamine, and a third component including at least one alkanolamine. A press roll, a shoe press and a process for the production of a press jacket are also provided.

Abstract: A method produces or machines a roller which is suitable to be used in a machine for producing or processing a fibrous web. The roller contains a roller core and at least one functional layer. The method is characterized in that the method includes the application of a functional layer. The application of the functional layer is performed by applying a coating substrate to the surface of a roller core. The application takes place simultaneously over at least half the roller width, preferably over 75% of the roller width, particularly preferably over the entire roller width. The entire applied coating substrate or parts thereof are hardened, forming a solidified structure.

Abstract: A press jacket for a press roller, in particular for a press roller of a shoe press for dewatering a fibrous material web, in particular a paper, cardboard, tissue or pulp web, or a transport band, in particular for a machine for producing or treating a fibrous material web, in particular a paper, cardboard or tissue machine, includes at least one layer containing polyurethane which contains a polyurethane matrix with a mixture of at least two prepolymers. Each prepolymer is a reaction product of two different polyols with a polyisocyanate.

Abstract: A roll covering is particularly suited for use in the press section of a machine for the production of a web of fiber-based material, for example a papermaking machine, a paperboard machine, or a tissue machine. The roll covering is arranged on a roll core which, in particular, is composed of metal or of a fiber-composite material. The modulus of elasticity of the roll covering is from 500 to 1500 N/mm2.

Abstract: A combination of a press felt with a pressure and/or suction roll covering for a papermaking machine, including a porous press felt with a carrier structure. The pressure or suction roll covering having a circumferential groove surface structure having a groove width in the range of 0.5 mm to 1.5 mm, a distance between grooves in the range of 1.5 to 2.5 mm and a groove depth in the range of 1.5 mm to 4 mm. A percentage of an open surface relative to an overall surface of the pressure roll covering is in a range of 20% to 50%. The suction roll covering additionally having an arrangement of holes with a plurality of suction holes completely penetrating through the suction roll covering, whereby a percentage of an open surface in relation to an overall surface of the suction roll covering is in a range of 30% to 50%.

Abstract: A combination of a press felt with a pressure and/or suction roll covering for a papermaking machine, including a porous press felt with a carrier structure. The pressure or suction roll covering having a circumferential groove surface structure having a groove width in the range of 0.5 mm to 1.5 mm, a distance between grooves in the range of 1.5 to 2.5 mm and a groove depth in the range of 1.5 mm to 4 mm. A percentage of an open surface relative to an overall surface of the pressure roll covering is in a range of 20% to 50%. The suction roll covering additionally having an arrangement of holes with a plurality of suction holes completely penetrating through the suction roll covering, whereby a percentage of an open surface in relation to an overall surface of the suction roll covering is in a range of 30% to 50%.

Abstract: The present invention relates to a method for producing a roller shell or roller covering of a roller from a PPDI-based polyurethane. To avoid stress cracks, the intention is to overcome the inadequacy in green strength as quickly as possible by the hardener that is added to the polyurethane bringing the pot time down to 5 to 60 seconds. The present invention also relates to a PPDI polyurethane for producing a roller shell or roller covering of a roller formed by mixing a PPDI prepolymer with a hardener, in particular for carrying out the method, wherein 60 to 99% by weight of the hardener is 1,4-butane diol, at most 40% by weight is diamine and at most 1% by weight is a catalyst.

Abstract: The invention relates to a method for producing a roller shell or roller lining of a roller made from a PPDI-based polyurethane plastic. The green strength shortcomings are to be overcome as quickly as possible to prevent stress cracks by the fact that the hardener added to the polyurethane shortens the working life to 5 to 60 seconds. The invention also relates to a PPDI polyurethane for the production of a roller shell or roller lining of a roller made by mixing a PPDI prepolymer with a hardener, in particular to carry out the method, wherein it is important that the hardener consists of 60 to 99% 1,4-butanediol, a maximum of 40% diamine, and at most 1% catalyst.