DK158237B - PROCEDURE FOR MANUFACTURING FIBER MATS - Google Patents

Description

in

DK 158237 B

The present invention relates to a method of making fiber mats for use as a laminate trunk in impregnating and forming fiber materials.

The laminate in question consists of a trunk and surface layer and can serve technical as well as decorative functions.

The stem of known laminates is composed of several sheets of kraft paper impregnated with preferably phenolic resin.

In thick laminates used in load-bearing structures, the content of paper sheets is large.

Thus, for this type of laminates, sheets of paper must first be prepared, which are then impregnated and assembled. This detour, paper making, is a process that requires both energy and manpower. A simplified approach will therefore also bring significant economic benefits.

In the present invention, it is possible to make laminates simpler and cheaper. The trunk or supporting structure of the laminate can be made as a fiber mat directly from the fiber material so that no sheets of paper are needed. The fibrous material may be of various kinds, for example cellulose fibers or artificial fibers, but preferably fibers of cellulosic material are used.

The features of the invention are apparent from the claims.

The invention will now be explained in more detail in connection with the drawing which shows a flow chart of the method according to the invention.

In the embodiment shown, the starting material is wood chips. This is washed in a washing machine 1 and then passed to a cleaning machine 2 via a preheater 3. The cleaning machine 2 is a tile cleaner with a cleaning house 4 under pressure. The intention is to produce fiber pulp substantially without splinter content. Via a blow line 5, the purified fiber material is further passed through the overpressure in the cleaning housing 4. In the blow line 5 and / or immediately before the purification, impregnating chemicals are added. These chemicals comprise a suitable binder, such as, for example, phenolic resin, in an amount of 10-50, preferably 20-50% by weight, relative to the fiber mass. A small amount of paraffin, up to 2%, can be added together with the phenolic resin.

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The impregnating chemicals are preferably carried out in the blowing conduit 5, where high velocity and turbulence prevail in the fiber pulp, thus the resin is distributed effectively on the individual fibers.

5 From the blowing line 5, the impregnated fiber material is all fed to a drying assembly 6 which includes a blower 7 and a heater 8 which heats air to a temperature lower than the curing temperature of the phenolic resin (max. 200 ° C, preferably below 160 ° C). The hot air and fiber pulp are transported through a drying tube 9 in which the drying takes place. The residence time in the dryer pipe 9 is very short. By controlling air temperatures and residence times, the desired degree of dryness can be achieved. Thus, in the dryer tube 9, the solvent of the impregnating agent and moisture adhered to the fibers are evaporated.

The dryer pipe 9 opens into a cyclone 10 where air and fibers are separated. The air leaving the cyclone usually has a temperature between € 0 and 8'5 ° C. Depending on the impregnating agents used, the air may contain substances which must not be discharged into the ambient atmosphere. The use of phenol-20 resin releases gases which, in some cases, must be recovered during drying. A portion of the air can then be recirculated to the inlet side of the blower 7 and the remaining portion is conducted for combustion. To avoid gases considered harmful, a temperature of 600 ° C is required. Appropriate equipment for this is commercially available.

The fiber material outlined in the cyclone 10 is weighed on a pair of fiber weights 11, preferably belt weights. The weighted amount of fiber is essential for the application of impregnating agent.

The fiber material is further conveyed in an air transport line to a storage container 12, in which the fiber material is introduced via an air separating cyclone 13. From the storage container, the fiber material is fed through a second air transport line to a forming station 14, for example of the type known from SE-PS 75 10795 -3.

The forming station 14 may be pneumatic or mechanical and is adjustable to various thicknesses. The forming station 14 comprises a distribution chamber 15 and a conveyor belt 16 in the form of a wire on which the fibers are placed. The transport air is sucked through the belt by means of a fan 17.

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An additional cyclone 18 and fans are used to separate and retract fibers that accompany the air, which fibers are fed back to the forming station 14. This means that mat formation is met with reasonable mold accuracy requirements (surface layer variations).

The molding is followed by a continuous pre-pressing in a press 19, preferably a band press of conventional design, whereby the remaining air is removed from the fiber mat. At the same time, the mat is consolidated so that it can be handled during subsequent machining. Loose fibers are sent back from the press for recycling in the molding station. The fiber mat is then divided into desired dimensions by means of longitudinal and transverse saws 20 and 21. By these, a metal detector 22 may preferably be arranged. Depending on the aperture in a laminate press not shown and its capacity, a pre-press can be arranged after the saws before the laminate press. . Optionally, heat may be added to shorten the heating time in the subsequent laminate press.

Fiber mats that are rejected, for example due to disagreement - 2Ό can be fed to a return container where the material is torn up and reused in the process. In cases where the fibers cannot be directly recycled, for example because they contain metal, the fiber material is sent to a special repellent container for special treatment.

Claims (2)

A method of producing fiber mats for use as a laminate frame, characterized by comprising the following steps: a) exposing individual fibers from the fiber material 5 by painting wood chips, b) impregnating the fibers with a binder such as phenolic resin in an amount of 10 -50, preferably 20-50% by weight, relative to the amount of fiber directly after the paint in a conveyor line wherein 10 has high velocity and turbulence, c) drying the fibers by hot air in an air conveyor line, d) separating air from the fiber material, e) forming a web of the fiber material by evenly distributing and depositing it on a movable band; f) final forming the fiber web into a fiber mat by pressing the fiber web in at least one step. 2. A method according to claim 1, characterized in that the amount of binder supplied is controlled by weighing the material immediately after the separation of air in step d).