method and machine for making fibre products from stock and a new type of fibre product

Abstract

The present invention relates to a method and a machine for making a fibre product. The invention also relates to a shaped body produced by the inventive method. According to the invention, a fibre product is formed on a first tool. The formed fibre product is then sandwiched between the first tool and a second tool and the surface of the second tool is heated to at least 220° C. to evaporate water from the fibre product. The tools are permeable to air and water When the fibre product has been dewatered to a dry solids content of at least 70%, the fibre product is subjected to microwave heating.

1 - 29 . (canceled) 
     
     
         30 . A method for producing a fibre product from stock, the method comprising the steps of:
 a) providing a first tool that is permeable to air and water;   b) providing a second tool and heating the second tool to a temperature of at least 220° C.;   c) providing a moulding tank and feeding stock to the moulding tank;   d) immersing the first tool in the stock in the tank;   e) forming an embryonic fibre product on the first tool by applying suction through the first tool;   f) removing the first tool from the stock;   g) bringing the first tool against the second tool such that the formed fibre product is sandwiched between the first and the second tool and heated by the second tool such that at least a part of the water in the formed fibre product is vaporized; and   h) dewatering the formed fibre product until it has reached a dry solids content of at least 70% after which the fibre product is subjected to drying by microwaves.   
     
     
         31 . A method according to  claim 30 , wherein the heating and vaporizing step that is carried out between the first tool and the second tool lasts for no more than 1 second. 
     
     
         32 . A method according to  claim 30 , wherein, during the forming step, no stock is fed to the moulding tank. 
     
     
         33 . A method according to  claim 32 , wherein, during the forming step, stock from (New) A machine vat is caused to by-pass the moulding tank and that, after the forming step, the stock from the machine vat is fed to the moulding tank. 
     
     
         34 . A method according to  claim 30 , wherein the forming step lasts 1-2 seconds. 
     
     
         35 . A method according to  claim 30 , wherein the fibre product is dewatered in several dewatering steps between opposed tools and subsequently subjected to steam before it is dried by microwaves. 
     
     
         36 . A method according to  claim 30 , wherein the stock has a dry solids content of 0.4-0.7% by weight. 
     
     
         37 . A method according to  claim 30 , wherein the stock has a dry solids content of 0.5% by weight. 
     
     
         38 . A method according to  claim 30 , wherein during the forming step the fibre product is dewatered to a dry solids content of 18-22% by weight. 
     
     
         39 . A method according to  claim 30 , wherein during the forming step the fibre product is dewatered to a dry solids content of 20% by weight. 
     
     
         40 . A method according to  claim 30 , wherein the first tool and the second tool are pressed against each other with a force generating an overpressure of no more than 1 MPa. 
     
     
         41 . A method according to  claim 30 , wherein the first tool and the second tool are pressed against each other with a force generating an overpressure of no more than 900 KPa. 
     
     
         42 . A method according to  claim 30 , wherein the pressure is in the range of 10-900 KPa. 
     
     
         43 . A method according to  claim 30 , wherein the stock is made from chemithermomechanical pulp (CTMP). 
     
     
         44 . A method according to  claim 30 , wherein suction is applied to the first tool also when the fibre product is sandwiched between the first tool and the heated second tool. 
     
     
         45 . A method according to  claim 44 , wherein also the second tool is permeable to air and water and that suction is applied also to the second tool when the fibre product is sandwiched between the tools so that steam and water can be evacuated through both the first tool and the second tool. 
     
     
         46 . A machine for producing fibre products from stock, the machine comprising:
 a) a moulding tank for holding stock;   b) a first tool that is permeable to air and water;   c) a second tool that is permeable to air and water;   d) means connected to the first tool for lowering the first tool into the tank and lifting the first tool out of the tank and for bringing the first tool against the second tool;   e) a source of underpressure connected to the first tool;   f) a source of heat arranged to heat the second tool and capable of heating the surface of the second tool to a temperature of at least 220° C. in order to vaporize water in a wet fibre product when the wet fibre product is sandwiched between the first and the second tool;   g) a microwave heater for additional removal of water from a fibre product that has previously been dewatered between the first tool and the second tool; and   h) means for transferring a fibre product from the second tool to the microwave heater.   
     
     
         47 . A machine according to  claim 46 , wherein a machine vat is arranged to supply stock to the moulding tank through a conduit and that there is also a by-pass conduit that can be used selectively such that stock from the machine vat can be either passed directly to the moulding tank or pumped around in a looped flow. 
     
     
         48 . A machine according to  claim 46 , wherein a steam shower is arranged before the microwave heater so that a fibre product to be passed through the microwave heater can be showered with steam before it is treated by the microwave heater. 
     
     
         49 . A machine according to  claim 46 , wherein the first tool comprises particles that have been sintered together to form a porous body. 
     
     
         50 . A machine according to  claim 49 , wherein also the second tool comprises particles that have been sintered together to form a porous body. 
     
     
         51 . A machine according to  claim 46 , wherein the first and second tools are mounted on holders that can be rotated between different angular positions. 
     
     
         52 . A machine according to  claim 46 , wherein, in addition to the first and the second tool, additional tools are arranged in a path from the pair of the first and second tool to the microwave heater, the additional tools forming cooperating pairs of tools where a fibre product may be subjected to additional dewatering and the additional tools further being arranged to convey a fibre product towards the microwave heater. 
     
     
         51 . Shaped body mainly comprising fibres, which fibres form a web which is continuous and form stable, and which preferably forms a three dimensional body, wherein the grammage is in the range 150-600 g/m 2  and wherein the orientation of the fibres is stochastic such that substantially the same strength properties are obtained independent of direction within the plane of the web, wherein the density is in the range 600-900 kg/m 3 . 
     
     
         52 . Shaped body according to  claim 51 , wherein the density is at least 700. 
     
     
         53 . Shaped body according to  claim 51 , wherein corners and/or areas having a sharp radius also presents substantially the same kind of continuous, homogenous web as a substantially flat surfaces of the body. 
     
     
         54 . Shaped body according to  claim 51 , wherein the roughness of a substantial portion of the surfaces on both sides of the body is within the range 750-3.000 ml/min. according to bendtsen ISO 8791-2. 
     
     
         55 . Shaped body according to  claim 51 , wherein the roughness of a substantial portion of the surfaces on both sides of the body is within the range 750-2.000 ml/min. according to bendtsen ISO 8791-2. 
     
     
         56 . Shaped body according to  claim 51 , wherein the roughness of a substantial portion of the surfaces on both sides of the body is within the range 750-1.500 ml/min. according to bendtsen ISO 8791-2. 
     
     
         57 . Shaped body according to  claim 51 , wherein the tensile index is in the range 50-100 kNm/kg. 
     
     
         58 . Shaped body according to  claim 51 , wherein the tensile index is in the range 65-100 kNm/kg. 
     
     
         59 . Shaped body according to  claim 51 , wherein the tensile index is in the range 80-100 kNm/kg. 
     
     
         60 . Shaped body according to  claim 51 , wherein the tensile index is in the range 90-100 kNm/kg. 
     
     
         61 . Shaped body according to  claim 51 , wherein the tear index is within the range 5-15 Nm 2 /kg. 
     
     
         62 . Shaped body according to  claim 51 , wherein the tear index is within the range 8-15 Nm 2 /kg. 
     
     
         63 . Shaped body according to  claim 51 , wherein the bonding strength of a surface layer of the body is in the range of 5-50% higher than the bonding strength of an intermediate layer near the centre portion of the web forming the body. 
     
     
         64 . Shaped body according to  claim 51 , wherein the bonding strength of a surface layer of the body is in the range of 7-30% higher, higher than the bonding strength of an intermediate layer near the centre portion of the web forming the body. 
     
     
         65 . Shaped body according to  claim 51 , wherein air resistance for the web, including corners/sharp bends of the body, is in the range of 60-200 sek by gurley. 
     
     
         66 . Shaped body according to  claims 65 , wherein air resistance for the web, including corners/sharp bends of the body, is at least 70 sek. 
     
     
         67 . Shaped body according to  claims 65 , wherein air resistance for the web, including corners/sharp bends of the body, is at least 80 sek. 
     
     
         68 . Shaped body according to  claim 51 , wherein the body is obtainable without any after pressing. 
     
     
         69 . Shaped body according to  claim 51 , wherein the body is obtainable without any after pressing action above 1.5 MPa after having obtained a dry solids content of at least 70%. 
     
     
         70 . Shaped body according to  claim 51 , wherein the body is obtainable without any after pressing action above 1.5 MPa after having obtained a dry solids content of at least 80%. 
     
     
         71 . Shaped body according to  claim 51 , wherein the body is obtainable without any after pressing action above 1.5 MPa after having obtained a dry solids content of at least 90%.