Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
  • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
  • B27K3/02—Processes; Apparatus
  • B27K3/12—Impregnating by coating the surface of the wood with an impregnating paste
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
  • B27N7/00—After-treatment, e.g. reducing swelling or shrinkage, surfacing; Protecting the edges of boards against access of humidity
  • B27N7/005—Coating boards, e.g. with a finishing or decorating layer

Definitions

• the invention relates to a process for covering particle board, particularly board having a thickness of from 10 to 40 mm, and having two main opposite surface layers of a surface density in excess of 800 kg/cu.m. and a face strength ranging from 8 to 12 kg/sq.cm, said covering comprising, for each surface, a first sheet of paper in contact with the layer and a second sheet of paper applied over said first sheet, said process comprising a pressing step.
• the "face strength” is determined according to the European Norm 311, entitled "Surface soundness".
• the invention concerns a covering of particle board with paper impregnated with a modified aminoplastic resin; the covering is produced in a short cycle medium pressure pressing line.
• the invention seeks to provide a process in which the covered board is suitable to be subjected to a post-forming process in which the covering paper may be curved, with an appropriate device, over the edge of the board, with a minimum radius of curvature of 4 mm and without cracks being formed in the covered board surface.
• This aim is achieved with a process of the type referred to at the beginning which is characterized in that it comprises the following steps: (A) providing first sheets of paper weighing between 60 and 180 g/sq.m.; (B) providing a first aqueous resin with a solids content of 30 to 60 wt% of urea-melamine-formaldehyde resin of low degree of condensation; from 4 to 10 wt% of a plasticizer from the family of the sulphonamides or the polyglycols; from 0.3 to 1 wt% of a wetting agent of the group formed by surfactants; from 0.5 to 3 wt% of an acid catalyst; and from 0.5 to 1 wt% of a mould stripping agent; (C) impregnating said first sheets with said aqueous resin, until said first sheets have a resin solids content of 45 to 60 wt% and a volatiles content of 5 to 7 wt%; (D) providing second sheets of paper; (E) providing a
• Said plasticizer is preferably o-p-toluene sulphonamide or diethylene glycol; said wetting agent is an alkyl nonyl phenol; said acid catalyst is an acid hydrolysis organic acid salt and said mould stripping agent is an aqueous silicone emulsion.
• the invention provides advantages over the present techniques of post-formable board coverings.
• One advantage lies in directly obtaining, in a single operation, a post-formable product by application of impregnated paper to the board in a short cycle, medium pressure press, instead of having to manufacture first an impregnated paper covering in a long cycle high pressure press and then adhere said covering to a base board in another press.
• Another advantage obtained from the invention is that a post-formable product is obtained by a paper covering having a much lower overall weight than that used in the long cycle high pressure coverings and with the use of aminoplastic resins instead of phenolic resins.
• the product of the present invention is obtained by covering a particle board of appropriate surface properties, specifically the density of its surface layer, and the face strength.
• the covering must comprise four sheets of impregnated paper per board, two on each side, with the sheets which are applied directly on the board surfaces being different from the outer ones applied over the former.
• the sheets of paper applied directly to the board must weigh from 60 to 180 grams per square metre and must be impregnated with a urea-melamine-formaldehyde resin of low degree of condensation, but having a long shelf life, modified with plasticizers from the families of the polyglycols and the sulphonamides.
• the outer sheets of paper applied over the previous ones are the usual decorative papers in all kinds of high and low pressure, long and short cycle coverings, but for this application they must be impregnated with a urea-melamine-formaldehyde resin of low degree of condensation, but having a long shelf life, modified with plasticizers from the families of the polyglycols and of the sulphonamides.
• the postformable covering of the present invention is produced in a short cycle, medium pressure press by application of an appropriate pressure and temperature to the ensemble formed by a particle board between four impregnated papers as described above, two on one side and the other two on the other side, the papers in contact with the board being different from the outer papers.
• a wood particle board having a surface layer density of 910 kg per cu.m. and a face strength of 12 kg/sq.cm., is placed between four impregnated papers, two on each side, of the following properties:
• Papers in contact with the lower and upper surfaces of the board paper of 132 g/sq.m. impregnated with resin such that the resin solids content of the impregnated paper is 58 wt% and the volatiles content is 7%.
• an aqueous resin having a solids content of 42% of urea-melamine-formaldehyde resin of low degree of condensation, with 9.5% of ortho-para-toluene sulphonamide as plasticizer, 0.9% of octyl nonyl phenol as wetting agent and 2.2% of para-toluene sulphonic acid ammonium salt was used.
• External decorated papers paper of 72 g/sq.m. impregnated with resin such that the resin solids content of the impregnated paper is 58 wt% and the volatiles content is 7%.
• an aqueous resin having a solids content of 48% of urea-melamine-formaldehyde resin of low degree of condensation, with 0.9% of octyl nonyl phenol as wetting agent, 1.5% of para-toluene sulphonic acid ammonium salt and 0.6% of M-75 mould stripping agent was used.
• the ensemble formed by the board and the four papers is subjected to a pressing operation in a medium pressure, short cycle installation, applying a specific pressure of 25 kg/sq.m and a temperature of the press surface in contact with the ensemble of 140°C, for a period of 60 seconds.
• a wood particle board having a surface layer density of 820 kg per cu.m. and a face strength of 10 kg/sq.cm., is placed between four impregnated papers, two on each side, of the following properties:
• Papers in contact with the lower and upper surfaces of the board paper of 160 g/sq.m. impregnated with resin such that the resin solids content of the impregnated paper is 50 wt% and the volatiles content is 6%.
• an aqueous resin having a solids content of 35% of melamine-formaldehyde resin of low degree of condensation, with 6.0% of diethylene glycol as plasticizer, 2.2% of octyl nonyl phenol as wetting agent and 1.2% of para-toluene sulphonic acid ammonium salt was used.
• External decorated papers paper of 120 g/sq.m. impregnated with resin such that the resin solids content of the impregnated paper is 51 wt% and the volatiles content is 6%.
• an aqueous resin having a solids content of 40% of melamine-formaldehyde resin of low degree of condensation, with 2.0% of octyl nonyl phenol as wetting agent, 1.0% of para-toluene sulphonic acid ammonium salt and 1.5% of M-75 mould stripping agent was used.
• the ensemble formed by the board and the four papers is subjected to a pressing operation in a medium pressure, short cycle installation applying a specific pressure of 25 kg/sq.m and a temperature of the press surface in contact with the ensemble of 145°C, for a period of 70 seconds.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Forests & Forestry (AREA)
• Manufacturing & Machinery (AREA)
• Laminated Bodies (AREA)
• Paints Or Removers (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Chemical And Physical Treatments For Wood And The Like (AREA)
• Apparatuses And Processes For Manufacturing Resistors (AREA)
• Paper (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)
• Die Bonding (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Removal Of Insulation Or Armoring From Wires Or Cables (AREA)
• Photoreceptors In Electrophotography (AREA)
• Control Of Vending Devices And Auxiliary Devices For Vending Devices (AREA)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

Family

ID=8288224

Family Applications (1)

Country Status (18)

Cited By (1)

Families Citing this family (5)

Family Cites Families (8)

• 1994
  • 1994-12-12 ES ES09402522A patent/ES2088768B1/es not_active Expired - Fee Related
• 1995
  • 1995-07-20 AT AT95500106T patent/ATE185512T1/de not_active IP Right Cessation
  • 1995-07-20 EP EP95500106A patent/EP0715935B1/en not_active Expired - Lifetime
  • 1995-07-20 DE DE69512745T patent/DE69512745D1/de not_active Expired - Lifetime
  • 1995-07-20 SI SI9530354T patent/SI0715935T1/xx unknown
  • 1995-08-11 HU HU9502369A patent/HU214376B/hu not_active IP Right Cessation
  • 1995-08-16 CA CA002156229A patent/CA2156229A1/en not_active Abandoned
  • 1995-08-17 EE EE9500032A patent/EE03261B1/xx not_active IP Right Cessation
  • 1995-08-23 HR HR9402522A patent/HRP950458A2/hr not_active Application Discontinuation
  • 1995-08-24 KR KR1019950026503A patent/KR100227652B1/ko not_active IP Right Cessation
  • 1995-08-28 YU YU57195A patent/YU57195A/sh unknown
  • 1995-08-31 CZ CZ952231A patent/CZ223195A3/cs unknown
  • 1995-09-04 CN CN95116211A patent/CN1073506C/zh not_active Expired - Fee Related
  • 1995-09-06 FI FI954171A patent/FI954171A/fi unknown
  • 1995-09-14 PL PL95310458A patent/PL310458A1/xx unknown
  • 1995-10-19 RU RU95117704A patent/RU2101167C1/ru active
  • 1995-10-19 TR TR95/01289A patent/TR199501289A2/xx unknown
  • 1995-12-08 NO NO954998A patent/NO954998L/no unknown

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