Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27G—ACCESSORY MACHINES OR APPARATUS FOR WORKING WOOD OR SIMILAR MATERIALS; TOOLS FOR WORKING WOOD OR SIMILAR MATERIALS; SAFETY DEVICES FOR WOOD WORKING MACHINES OR TOOLS
  • B27G11/00—Applying adhesives or glue to surfaces of wood to be joined
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C5/00—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
  • B05C5/002—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the work consisting of separate articles
  • B05C5/004—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the work consisting of separate articles the work consisting of separate rectangular flat articles, e.g. flat sheets

Definitions

• the present invention relates to a method for applying glue to the surface of wooden parts, in which the ready-to-use glue is applied as a cast film to the surface of the wooden parts.
• DE-B 21 01 800 describes a method for applying glue in the manufacture of wood glue constructions, the glue being kept circulating in a circuit and being applied to the broad side of the workpiece in the form of cords.
• a disadvantage of this method is that when the wooden parts are pressed, the glue does not form a coherent film in places and defects can occur in the wooden glue constructions.
• DE-A 24 16 032 describes a method for assembling wood products, the liquid resin and the liquid hardener being applied separately by means of a strip distributor.
• a disadvantage of this process is that, in addition to the formation of imperfections described above, inadequate mixing of hardener and resin can also occur in places, whereby wetted points can arise which do not harden or harden only insufficiently.
• EP-B-95 678 describes a method for forming a liquid film on a board by casting a flow curtain from a dispensing container.
• EP-A-241 891 describes a device for applying glue to wooden parts, with the aid of which a cast film is formed by means of a guide element.
• the German patent application P 37 12 347.5 sees for this lead organ improvements in the form of anti-congestion devices. According to both documents, resin and hardener are applied separately by two devices.
• the object of the present invention was to develop a method for applying glue to the surface of wooden parts, which allows a uniform application of ready-to-use glue in one step and avoids defects in the form of non-wetted surfaces or incomplete mixing of the resin components.
• the task was solved by applying a ready-to-use glue as a cast film using a guide element.
• the present invention relates to a method for applying a ready-to-use glue to the surface of wooden parts, with a ready-to-use glue held in circulation in a circuit via a storage container, a pouring head provided with a guide element, under which a feed device for wooden parts is arranged, and a collecting trough , whereby the ready-to-use glue is applied as a cast film to the surface of the wooden parts.
• the device required for this method is known and is not the subject of the present invention. It is described in German patent application P 37 12 347.5 and essentially consists of a storage container, a pouring head designed as a cylindrical hollow body with outlet openings and a guide element, a feed device for the wood to be coated, a collecting trough and the associated ring line with two pumps .
• the devices on the guide element of the pouring head that prevent air congestion are essential for the process.
• a ready-to-use glue i.e. Apply a glue that contains all the components required for its further processing or curing, such as solvents, catalysts, hardeners, additives and auxiliary substances, fillers and extenders or their mixtures, and the excess amount is collected in a collecting container and applied to the Cycle returned.
• the ready-to-use glue is heated to temperatures of 5 to 30 ° C., preferably 10 to 20 ° C.
• the ready-to-use glue can be tempered at any point on the device wetted with glue, preferably in the collecting container of the device.
• the method according to the invention allows the use of various types of liquid glue, e.g. of urea-formaldehyde, melamine-urea-formaldehyde, melamine-urea-phenol-formaldehyde, phenol-resorcinol-formaldehyde, resorcinol-formaldehyde, phenol-formaldehyde, polyvinyl acetate glues, their mixtures and other glues customary in wood processing.
• liquid glue e.g. of urea-formaldehyde, melamine-urea-formaldehyde, melamine-urea-phenol-formaldehyde, phenol-resorcinol-formaldehyde, resorcinol-formaldehyde, phenol-formaldehyde, polyvinyl acetate glues, their mixtures and other glues customary in wood processing.
• Melamine-urea-formaldehyde condensates, resorcinol-urea-formaldehyde condensates or polyvinyl acetate glues are preferably used.
• the pot life is adjusted via a suitable choice of, for example, hardener or catalyst so that a processing time of at least half an hour, preferably at least one hour, is ensured.
• the measures required for this are generally known.
• just enough acid or acid-forming compounds are used as hardeners that the viscosity of the ready-to-use glue does not exceed 25,000 mPas during the processing time.
• formaldehyde or formaldehyde-forming compounds are used as hardeners.
• the ready-to-use glues can be used in both thixotropic and non-thixotropic settings.
• the thixotropic settings contain common thixotropic agents such as silicates.
• customary additives and auxiliaries such as fillers and extenders, for example cereal or leguminous flours, can also be present in the ready-to-use glue in amounts of up to 50% by weight, based on the solids of the ready-to-use glue.
• the processing viscosity of the ready-to-use glue is 250 to 12000, preferably 1000 to 10000 mPa ⁇ s at 20 ° C.
• the feed rate of the wood that runs under the glue film is 0.5 to 4 m / s, preferably 1.5 to 3 m / s.
• the application of the ready-to-use glue is 80 to 600 g / m2, preferably 300 to 500 g / m2.
• Wooden parts with a uniform layer of glue are obtained by the process according to the invention. After hardening, this can serve as a surface treatment or the glued wood parts can be used to produce laminated wood materials or glulam.
• the method according to the invention was tested in gluing tests with beech wood specimens of 150 x 300 mm format.
• This glue liquor viscosity approx. 1800 mPa ⁇ s
• test pieces were placed on the glued ones and pressed with a pressure of approx. 8 N / mm2.
• the test pieces were stored in a standard atmosphere (20 ° C./65% relative atmospheric humidity) for 24 hours under pressure.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Wood Science & Technology (AREA)
• Forests & Forestry (AREA)
• Chemical And Physical Treatments For Wood And The Like (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6364525

Family Applications (1)

Country Status (5)

Cited By (2)

Citations (3)

• 1988
  • 1988-10-06 DE DE19883834027 patent/DE3834027A1/de not_active Withdrawn
• 1989
  • 1989-09-12 FI FI894301A patent/FI894301A/fi not_active Application Discontinuation
  • 1989-09-30 EP EP89118172A patent/EP0366944A1/de not_active Withdrawn
  • 1989-10-05 DK DK490889A patent/DK490889A/da not_active Application Discontinuation
  • 1989-10-05 NO NO89893971A patent/NO893971L/no unknown

Patent Citations (3)

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