Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B21/00—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties

Definitions

• the present invention relates to adhesives, and more particularly to a hot melt adhesive for laminating decorative veneers to wood substrates and to the laminates created thereby.
• Wood products made from solid wood boards of hardwood or softwood are generally preferred for such uses, but solid wood is relatively expensive, and thus is not necessarily desired by all consumers.
• An alternative is to use thin wood veneers having the desired appearance bonded to a less expensive substrate.
• trees of the required type, size and quality which provide a source for wood veneers become more scarce, the manufacturer of veneers is also becoming relatively expensive.
• wood construction products that are more economical have been developed.
• particleboard, fiberboard, orientated strandboard, plywood, and other similar boards formed from relatively low-grade wood that may not otherwise be usable in the construction industry have been adopted.
• boards formed from wood particles, such as wood chips, wood flakes or other wood fragments are also being used more and more frequently in the construction industry, particularly for subsurfaces.
• waste agricultural products such as straw, have also been used as subsurfaces.
• Such products have acceptable quality and integrity that is more than adequate for such uses. However, they are typically characterized by uneven, rough and unattractive surfaces that do not provide a "finished" look.
• the substrate or base formed from low-grade wood and agricultural products typically has a decorative top layer adhered thereto to provide an attractive and protective finish.
• the decorative top layer usually is either a vinyl between 2 and 6 mils thick or a paper imprinted with decorative inks to yield a desired color or pattern, but may also be a thin layer of wood veneer.
• Wood products laminated with decorative papers generally can be manufactured at a lower cost than the corresponding vinyl covered or wood veneer covered laminates, and in many instances, provide superior aesthetics. Nevertheless, despite their lower cost and desirable aesthetic properties, decorative papers have been too fragile for many types of products. In particular, the decorative paper can easily become damaged during normal use due to the relatively fragile nature of paper which thus offsets any aesthetic advantage of decorative paper.
• the present invention provides a hot melt adhesive interposed between a substantially planar substrate formed from a wood product and a decorative top layer for bonding the top layer to the substrate wherein the adhesive includes, as a primary ingredient thereof, a polymer or polymers containing one or more monomers which when polymerized or copolymerized, yields a Shore D hardness greater than the Shore D hardness of the substrate.
• Monomers of this type include styrene, methylmethacrylate, vinyl acetate, vinyl chloride, diphenylmethane diisocyanate, and other monomers that produce polymers with a T g greater than 20°C.
• the components of the hot melt adhesive include a mixture of the following ingredients:
• the components of the adhesive add up to 100% by weight.
• the adhesive composition may also contain other ingredients which can modify particular physical properties as desired.
• a particularly preferred embodiment of the invention includes a mixture of the following ingredients: (a) about 57.5% of polystyrene as the high Shore D hardness polymer; (b) about 1 1.5% of a terpene phenolic resin as the adhesion promoting tackifier;
• a wood laminate constructed with the above described hot melt adhesive.
• the wood laminate comprises a wood base or substrate, a decorative top layer, and a hot melt adhesive having elevated hardness, as described above, for bonding the decorative top layer to the wood base.
• the wood base is fiberboard or particleboard
• the decorative top layer is paper.
• the present invention relates to a laminated decorative structure used in the construction industry for walls, flooring, cabinetry, furniture and other surfaces in houses and buildings.
• This structure is particularly useful in the furniture industry.
• the laminated wood product is comprised of a substantially planar base or substrate formed from a wood product, a decorative top layer, and a hot melt adhesive having elevated hardness interposed between the substrate and top layer for bonding the top layer to the substrate.
• a hot melt adhesive having elevated hardness interposed between the substrate and top layer for bonding the top layer to the substrate.
• it may also be used to bond the top layer to a profile material, such as those used on headboards and armoires.
• the substrate is a substantially planar, integral sheet or board formed from a wood product.
• the wood product may have derived from wood particles from trees such as chips, flakes, sawdust, paper or fragments, as well as from agricultural products such as straw.
• the particles of wood may be derived from a variety of trees including both hardwood and softwood trees. Examples of such trees include, but are not limited to, aspen, beech, birch, cedar, firs, hemlock, pine and spruce.
• Just about any source of tree may be employed, and the particular type of tree used or potentially useable wood particles oftentimes depends upon the region or country where the wood product is produced as some species of trees may be indigenous to only limited regions or lands.
• the substantially planar wood substrate encompasses particleboard, fiberboard, orientated strandboard, hardboard, waferboard, plywood, chipboard, strawboard and the like.
• the substrate is described herein as having an uneven or rough surface, and the substrates described above generally are formed with such a surface.
• uneven or rough surfaces are normally not capable of being coated, with paint or decorative layers such as vinyl, paper, or veneers, to provide a high quality, smooth or attractive "finished" outer surface.
• Techniques for manufacturing wood substrates are well known in the art.
• the substrates may be manufactured by compressing and/ or heating (typically at temperatures of up to about 375°F) the wood particles to form a structurally integral sheet.
• a bonding agent is normally applied to the surface of the wood particles prior to pressing, and examples of such bonding agents are urea/ formaldehyde resin, phenol/ formaldehyde resin, melamine/ formaldehyde resin, polymeric isocyanate resin and the like.
• the bonding agent may be in either powder or liquid form and is preferably a phenol/ formaldehyde resin which is typically applied in amounts in the range of 1.8 to 2.3% by weight to the wood particles.
• a wax such as a petroleum-based wax
• a wax such as a petroleum-based wax
• preservatives and other additives may also be applied to the wood particles as is conventional.
• a wide variety of papers may be used such as kraft, rice, bamboo, and/ or corn, but particularly preferred is kraft or rice paper.
• the paper may be bleached or unbleached.
• the paper may be used in a variety of thicknesses depending upon the particular application.
• the paper is usually printed and may have a durable coating over the printing.
• the particular process of manufacture of the wood substrate may influence the selection of the thickness of the paper as some processes impose higher demands on strength properties of the paper in order to resist tearing, or puncturing during manufacture.
• the thickness of paper is between 0.5 to 6 mils.
• the decorative top layer of the wood panel may also be veneer, i.e. a thin layer of wood covering the surface of the panel.
• the hot melt adhesive is interposed between the substrate and the decorative top layer, and functions to bond the top layer to the substrate.
• the adhesive comprises, as a primary ingredient thereof, a polymer or copolymer containing one or more monomers which when polymerized or copolymerized yields a film having a Shore D hardness greater than the Shore D hardness of the substrate.
• the Shore D hardness of particleboard is about 55. Therefore, the Shore D hardness of the adhesive coating or film should be at least 55, and more preferably at least 65, and most preferably at least 67.
• Monomers of this type produce polymers or copolymers with at least one T g greater than or equal to 20°C or 293°K, but less than or equal to the temperature attained by the adhesive during the bonding or heat sealing operation.
• Monomers of this type include, but are not limited to styrene, methylmethacrylate, vinyl acetate, vinyl chloride, diphenylmethane diisocyanate, and other monomers that produce polymers with at least one T g greater than 20°C.
• the monomers that can be either homopolymerized or copolymerized to obtain these polymers include but are not limited to: 1.
• Monomers that produce main chain acyclic carbon polymers such as:
• dienes that result in polydienes such as neoprene, poly butadiene, polyisoprene, and others;
• alkenes that result in polyalkenes such as polybutene- 1 , poly butyle thy lene, polyethylene, polyisobutylene, polymethylene, polypropylene, and others;
• acrylic acid and acrylic acid esters that result in polyacrylics and polyacrylates such as polyacrylic acid, polybenzyl acrylate, polybutyl acrylate, polyethyl acrylate, polycyano acrylates, and others;
• acrylamides that result in polyacrylamide s such as polyacrylamide, polybutylaciylamides, polyisopropylacrylamide, and others;
• methacrylic acid and methacrylic acid esters that result in polymethacrylics and polymethacrylates such as polybutylmethacrylate, polyethylmethacrylate, polymethacrylic acid, polyme thy lmethacry late, polypropylmethacrylate and others;
• acrylamides and methacrylamides that result in polyacrylamide s and polymethacrylamides such as poly (4- butoxycarbonylphenylmethacrylamide), poly (N-tert- butylmethacrylamide), poly (N-carboxyphenylmethacrylamide), and others;
• alpha or beta substituted acrylics or methacrylics that result in polyacrylics and polymethacrylics such as polybutylchloroacrylate, polybutylcyanoacrylate, polye thy lchloroacry late, and others
• vinyl ethers and vinyl thioethers that result in polyvinylethers and polyvinyl thioethers such as polybutoxyethylene, polybutylthiothylene, polyethoxyethylene, polymethoxyethylene, polymethylthioethylene, and others
• vinyl alcohol that results in polyvinylalcohols such as polybenzoylethylene, poly (4-chlorobenzoylethylene), polyvinylalcohol, and others;
• (k) vinyl esters that result in polyvinylesters such as polyvinylacetate, polyvinylformate, polycyclopentanoyloxyethylene, polybenzoylethylene, and others;
• polystyrene that result in polystyrenes such as polybutylstyrenes, polychlorostyrenes, polyethylstyrenes, polymethylstyrenes, polystyrene, and others;
• phenylenes that result in polyphenylenes such as poly (2-bromo-l,4-phenyleneethylene), poly (2,5-dichloro-l,4- phenyleneethylene), poly (1,4-phenyleneethylene), and others;
• other monomers that form polymers such as polycyclobutene, poly (1,4-naphthyleneethylene), and others;
• Monomers that produce main chain heteroatom polymers such as:
• polyoxides such as polyoxyethylenes, polyoxymethylene, polyoxypropylene, and others;
• polycarbonates such as poly(oxycarbonyloxy-2-chloro-
• polyesters such as poly(ethylene adipate), poly(ethylene terephthalate), poly(oxyethyleneoxyadipoyl) and others;
• polyanhydrides such as poly(oxycarbonyl- 1 ,4- phenylenehexafluorotrimethylene- 1 ,4-phenylene-carbonyl) , poly(oxycarbonyl- 1 ,4-phenylenepentamethylene- 1 ,4- phenylenecarbonyl), poly(oxyisophthaloyl), poly (methacrylic anhydride) and others;
• polyamides such as poly(imino-5-tert- butylisophthaloyliminomethylene- 1 ,4-phenylenemethylene), poly (iminocarboxyl- 1 ,4-cyclohexylenemethylene) , poly(iminoisophthaloyliminohexamethylene) and any of the numerous nylons known in the art; and others;
• polyacetals such as poly(2-ethyl- l ,3-dioxa-4,6- cyclohexylenemethylene), poly(vinyl acetal), poly(vinyl butyral) and others;
• polypiperazines such as poly(l,4-piperazinediyladipoyl), poly( 1 ,4- piperazinediylcarboxyloxyethyleneoxycarbonyl) , poly( 1 ,4- piperazinediylisophthaloyl) and others;
• Isocyanates such as:
• the adhesive maintain a Shore D hardness greater than the Shore D hardness than the wood substrate. This is especially important when the wood panel is utilized in a horizontal manner where items may be placed on top of the panel, and if the adhesive is too soft, these items will leave an impression mark in the panel.
• the adhesive composition of the present invention includes the following: The components of the composition adding up to 100% by weight.
• the flexibilizing polymers useful in the present compositions include a polymer or copolymer containing one or more monomers previously listed, but preferably is selected from SIS (styrene-isoprene-styrene) available under the trade name "Kraton” from Shell; SBS (styrene- butadiene- styrene) available under the trade name "Vector” from Dexco; SEBS (styrene-ethylene-butylene-styrene) available under the trade name "Kraton” from Shell; EVA (ethylene-vinyl acetate) available under the trade name "Elvax” from DuPont; APAO (amorphous polyalpha olefin) available under the trade name "Rextac” from Huntsman Corporation; SBR (styrene- butadiene-rubber) available under the trade name "Stereon” from Firestone; (VA) vinyl acetate homopolymer available under the trade name "Vamipol” from
• tackifying resins which are used in the hot melt adhesives of the present invention are those which extend adhesive properties and improve specific adhesion.
• the term "tackifying resin” includes: (a) natural and modified rosin such as, for example, gum rosin, wood rosin, tall-oil rosin, distilled rosin, hydrogenated rosin, dimerized rosin and polymerized rosin; (b) glycerol and pentaerythritol esters of natural and modified rosins, such as, for example, the glycerol ester of pale wood rosin, the glycerol ester of hydrogenated rosin, the glycerol ester of polymerized rosin, the pentaerythritol ester of pale wood rosin, the pentaerythritol ester of hydrogenated rosin, the pentaerythritol ester of tall oil rosin and the phenolic modified pentaeryth
• polyterpene resins having a softening point, as determined by ASTM method E28-58T, of from about 10°C to 140°C, the latter polyterpene resins generally resulting from the polymerization of terpene hydrocarbons, such as the mono-terpene known as pinene, in the presence of Friedel-Crafts catalysts at moderately low temperatures; also included are the hydrogenated polyterpene resins; (d) copolymers and terpolymers of natural terpenes, e.g. styrene /terpene, ⁇ -methyl styrene /terpene and vinyl toluene /terpene;
• phenolic-modified terpene resins such as, for example, the resin product resulting from the condensation, in an acidic medium, of a terpene and a phenol
• aliphatic and cycloaliphatic petroleum hydrocarbon resins having
• Ring and Ball softening points of from about 10°C to 140°C the latter resins resulting from the polymerization of monomers consisting primarily of aliphatic or cycloaliphatic olefins and diolefins; also included are the hydrogenated aliphatic and cycloaliphatic petroleum hydrocarbon resins; examples of such commercially available resins based on a C5-olefin fraction of this type are Piccotac 95 tackifying resins sold by Hercules Corp. and Eastotac H 115R sold by Eastman Chemical Company;
• Tackifying resins which are useful for the present invention can perhaps include polar tackifying resins, however, the choice of available polar tackifying resins is limited in view of the fact that many of the polar resins appear only partially compatible with the polymers.
• the tackifying resins can be selected from any of the nonpolar types, which are commercially available.
• Preferred resins are terpene phenolic resins such as Sylvarez TP 2040 available from Arizona Chemical.
• a plasticizer can be present in the composition of the present invention in amounts of about 0% to about 12%, by weight, preferably from about 2% to about 8%, and most preferably from about 4% to 7%, in order to provide desired viscosity control.
• a suitable plasticizer may be selected from the group which includes the usual plasticizing oils, such as mineral oil, but also olefin oligomers and low molecular weight polymers, as well as vegetable and animal oil and derivatives of such oils.
• the petroleum derived oils which may be employed are relatively high boiling temperature materials containing only a minor proportion of aromatic hydrocarbons. In this regard, the aromatic hydrocarbons should preferably be less than 30%, and more particularly less than 15%, by weight, of the oil.
• the oil may be totally non-aromatic.
• the oligomers may be polypropylenes, polybutenes, hydrogenated polyisoprene, hydrogenated butadiene, or the like having average molecular weights between about 350 and about 10,000.
• Suitable vegetable and animal oils include glycerol esters of the usual fatty acids and polymerization products thereof.
• the plasticizer that finds usefulness in the present invention can be any number of different plasticizers but it has been discovered that a plasticizer which includes mineral oil such as that available under the trade name "Hydrobrite 550" from Witco is particularly useful in the present invention.
• Other liquid polybutenes having average molecular weights less than 5,000 may also be used.
• plasticizers have typically been employed to lower the viscosity of the overall adhesive composition without substantially decreasing the adhesive strength and/or the service temperature of the adhesive as well as extend the open time of the adhesive.
• the present adhesive may include a stabilizer in an amount of from about 0.1% to about 5% by weight. Preferably from about 0.5% to 4% and most preferably from about 0.6% to 2.5% of a stabilizer is incorporated into the composition.
• the stabilizers which are useful in the hot melt adhesive compositions of the present invention are incorporated to help protect the polymers noted above, and thereby the total adhesive system, from the effects of thermal and oxidative degradation which normally occurs during the manufacture and application of the adhesive as well as in the ordinary exposure of the final product to the ambient environment. Such degradation is usually manifested by a deterioration in the appearance, physical properties and performance characteristics of the adhesive.
• Hindered phenols are well known to those skilled in the art and may be characterized as phenolic compounds which also contain sterically bulky radicals in close proximity to the phenolic hydroxyl group thereof.
• tertiary butyl groups generally are substituted onto the benzene ring in at least one of the ortho positions relative to the phenolic hydroxyl group.
• the presence of these sterically bulky substituted radicals in the vicinity of the hydroxyl group serves to retard its stretching frequency and correspondingly, its reactivity; this steric hindrance thus providing the phenolic compound with its stabilizing properties.
• Representative hindered phenols include: l ,3,5,-trimethyl-2,4,6-tris(3-5-di-tert-butyl-4-hydroxybenzyl) benzene; pentaerythritol tetrakis-3(3,5-di-tert-butyl-4-hydroxyphenyl) propionate; n-octadecyl-3(3,5-di-tert-butyl-4-hydroxyphenyl) propionate;
• a stabilizer is pentaerythritol tetrakis-3(3,5- di-tert-butyl-4-hydroxyphenol) propionate.
• preferred antioxidants include "Irganox 1010" available from Ciba-Geigy and "Cyanox LTDF' available from Cytec Industries.
• These stabilizers may be further enhanced by utilizing, in conjunction therewith; (1) synergists such as, for example, as thiodipropionate esters and phosphites; and (2) chelating agents and metal deactivators as, for example, ethylenediaminetetraacetic acid, salts thereof, and disalicylalpropylenediimine.
• synergists such as, for example, as thiodipropionate esters and phosphites
• chelating agents and metal deactivators as, for example, ethylenediaminetetraacetic acid, salts thereof, and disalicylalpropylenediimine.
• Fillers may also be incorporated into the adhesive composition in amounts ranging from 0% to 20% by weight, preferably 1% to 8% by weight, and most preferably 3% to 6% by weight. These are inert in the formulation, and are typically added as an anti-blocking agent. Fillers may include alumina, hydrated alumina such as aluminum oxide trihydrate (AI2O3-3H2O), silicates such as magnesium silicates, aluminum silicate, sodium silicate, potassium silicate and the like, mica, talc, calcium carbonate (CaCO ⁇ ), silica, clay, wollastonite, feldspar, boron nitride, glass micro spheres, ceramic micro spheres, thermoplastic micro spheres, baryte and wood flour.
• alumina hydrated alumina such as aluminum oxide trihydrate (AI2O3-3H2O)
• silicates such as magnesium silicates, aluminum silicate, sodium silicate, potassium silicate and the like
• mica talc
• CaCO ⁇ calcium carbonate
• Optional conditioning additives may be incorporated into the adhesive composition in order to modify particular physical properties. These additives may include colorants, such as titanium dioxide and zinc oxide, defoamers, sequestrants, antiblocking agents, anticling agents, surfactants, thickeners, fluorescent agents and other commonly known and used additives. Such additives can be present in amounts ranging from 0% to about 30% by weight.
• Defoamers in the amount of 0% to 3%, preferably 0% to 1.5%, may also be added to the adhesive composition.
• Typical defoamers include silicone based, mineral oil based, surfactant based, and kerosene based compounds with the preferred defoamer being DEEFO-97-2, a mineral oil based defoamer available from Ultra Additives, Inc.
• Opacifiers in amounts ranging from 0% to 5%, preferably 0% to 2.5% may also be added to the adhesive composition. Opacifiers are added to the adhesive composition to insure that the wood substrate cannot be seen through the decorative top layer, particularly when the top layer is a paper. Typical opacifiers include titanium dioxide, calcium carbonate, barium sulfate, and other light reflecting powdered minerals or metallic oxides. From about 0% to 5%, preferably 0% to 2.5% of a thickener may also be added to the adhesive composition. Thickeners are used to increase the viscosity of the resultant adhesive without substantially affecting its adhesive characteristics. Typical thickeners include bentonites, attapulgates, and other thickening or gelling agents. Melt flow modifiers in amounts ranging from 0% to 40% preferably
• melt flow modifiers are added to the composition to improve the flow of the dried adhesive film under heat and pressure while sealing the decorative top layer to the wood substrate.
• Typical melt flow modifiers include: phosphate esters, benzoate esters, phthalate esters, wood rosin esters, gum rosin esters, tall oil rosin esters, aromatic hydrocarbon resins, aliphatic hydrocarbon resins, cycloaliphatic resins, all their hydrogenated counterparts, and any combinations of the aforementioned, as long as the Shore D hardness is maintained.
• the preferred melt flow modifiers are phosphate esters, tall oil rosin esters, and solid benzoate esters.
• the most preferred melt flow modifier is Santicizer 141, a phosphate ester plasticizer available from Monsanto.
• the hot melt adhesive composition of the present invention may be formulated using any of the techniques known in the art.
• a representative example of the prior art mixing procedure involves placing all the components, except the polymer, in a jacketed mixing kettle equipped with a rotor, and thereafter raising the temperature of the mixture to a range from 330°F to 400°F to melt the contents. It should be understood that the precise temperature to be used in this step would depend on the melting points of the particular ingredients.
• the polymer(s) are subsequently introduced to the kettle under agitation and the mixing is allowed to continue until a consistent and uniform mixture is formed.
• the contents of the kettle is protected with inert gas such as carbon dioxide and nitrogen during the entire mixing process.
• the resulting hot melt adhesives may then be applied to substrates using a variety of coating techniques. Examples include hot melt slot die coating, hot melt wheel coating, hot melt roller coating, melt blown coating and spiral spray coating.
• Antioxidant Irganox 1010 3 ; 3 * 3.2 3 3 ' 3 ' 3 3.
• EXAMPLE 2 The performance of the adhesives prepared in accordance with Example 1 were tested for adhesion and flexibility in accordance with the "Crinkle Test.”
• the Crinkle Test is performed by coating each adhesive composition onto either 30 gram or 60 gram paper at 2.5 mils and allowed to cool for 24 hours before testing. The test is to take a 4 inch coated sample and crinkle it up with your hand. The sample is then unfurled and examined for cracking and flaking off of the hot melt coating/ adhesive. The results are reported in Table 2.
• EXAMPLE 3 The performance of some of the adhesives prepared in accordance with Example 1 were also tested for potential blocking. The blocking test was run using the 60 gram paper with the adhesive coated at 2.5 mils and conditioned at room temperature for 24 hours. 2 inch by 4 inch samples were cut and placed into a Kohler spring block tester at 100 psi for 16 hours at the desired temperature. All samples were blocked adhesive coating to printed side of paper veneer.
• Shore D hardness of paper/ adhesive /particleboard laminate is run by laminating a 6 inch by 6 inch structure in a heated platen press at 250°F, at 80 psi for 3 seconds. Adhesive was 1.25 mils thick. The laminate is then conditioned at room temperature for 24 hours before testing. Then 6 readings were taken with a Shore D durometer.
• Shore D hardness of paper/ adhesive/ MDF laminate is run by laminating a 6 inch by 5 inch structure in a heated platen press at 250°F, at 80 psi for 3 seconds. Adhesive was 2.0 mils thick. The laminate is then conditioned at room temperature for 24 hours before testing. Then 6 readings were taken with a Shore D durometer.
• Example 3 the Shore D hardness of the adhesives prepared in accordance with Example 1 was compared with the Shore D hardness of the commercially available EVA hot melt adhesive ARDAL T8028/2 from Ato Findley SA. The results are reported in Table 4.
• Example 1 The adhesive compositions of Example 1 successfully bonded decorative paper to particleboard and fiberboard. 2.
• the data in column 5 of Table 4 demonstrate that laminates constructed with fiberboard and the adhesives of Example 1 have greater Shore D hardness than either a laminate constructed with the EVA hot melt adhesive or the fiberboard substrate itself.
• the adhesive lamination using 1296- 15W has a Shore D hardness of 16.4
• a lamination with the EVA hot melt adhesive (T8028/2) has a Shore D hardness of only 47.8.
• the fiberboard itself only has a Shore D hardness of 64.8.
• the laminated wood products of the present invention may be manufactured using a variety of methods. For example, the wood substrate may be manufactured, coated with the adhesive and then the decorative top layer may be applied to the adhesive.
• the resulting lamination is then heated, preferably under pressure in a press or between rolls, to affect bonding of the decorative top layer to the wood substrate.
• the adhesive interposed between the wood substrate and top layer is heated to a temperature above the melting point of the adhesive composition in order to affect bonding, i.e. to a temperature in excess of 150°F, especially in the range of about 175°F to 275°F, and up to about 375°F.
• the resultant laminated wood panel is then allowed to cool to solidify the adhesive and affect bonding.
• the adhesive composition is applied to the decorative top layer, cooled, and then the top layer is rolled up for later use.
• the top layer together with the adhesive coating thereon, would then later be contacted with the wood substrate, and subjected to heat and pressure to affect bonding, as discussed above.
• the adhesive may be formed into a film, cooled and rolled up for later use.
• the wood substrate, the film of adhesive, and the decorative top layer of paper, vinyl or veneer are then brought into contact with each other and subjected to heat and pressure to affect bonding, as discussed above.
• the laminated decorative products or structures of the present invention may be used in a variety of end uses, depending in particular on the nature of the product.
• the laminated products may be panels used as the interior surfaces in buildings for walls. This structure may also be used in the furniture industry, where it may be used for a substantially flat surface or for a profiled surface.
• laminated wood products wherein the top decorative layer is paper may be painted to provide an attractive surface with the interposed layer of adhesive providing a smooth surface that tends to cover defects, such as roughness, indentations or unevenness, in the surface of the wood substrate.
• the top decorative paper layer may be preprinted with the desired pattern so that no subsequent painting is necessary.
• panels coated with veneer may be shellacked or coated with varnish or the like to preserve or enhance the attractive features of the veneer.
• the panels may also be used as sublayers in the construction industry to provide barriers to moisture or the like and to provide a surface that is capable of having other layers attached thereto.

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• 2000
  • 2000-09-21 JP JP2000286399A patent/JP2001232721A/ja active Pending
  • 2000-12-21 AU AU2001222879A patent/AU2001222879A1/en not_active Abandoned
  • 2000-12-21 WO PCT/US2000/034915 patent/WO2001062492A1/en active Application Filing

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