Note: Descriptions are shown in the official language in which they were submitted.
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"METHOD FOR PRODUCING
LAMINATED ARTICLES"
R~rk~rolln~ of the ll~v~-~tion
This application is a continuation of Serial No. 08/206,810 filed March 4, 1994,
now U.S. Patent No. 5,504,126; and a continuation-in-part of Serial No. 08/219,335, filed
March 29, 1994, abandoned in favor of Serial No. 08/347,278, filed November 30, 1994.
Serial No. 08t206,81Q itself is a co~tim)~tion-in-part of Serial No. 07/882,839 filed May
15, 1992, now U.S. Patent No. 5,304,592; Serial No. 08/51,627 filed April 22, 1993, now
U.S. Patent No. 5,476,89; and Serial No. 08/35,720 filed March 23, 1993. Both Serial
Nos. 07/822,839 and 08/51,627 are in turn co~ ions-in-part of Serial No. 07/788,982
filed November 7, 1991, now ~nt10n~l. The co..l~ of the above referenced appli~ n.c
are hereby incorporated by reference into the present disclosure.
The subject invention relates generally to a method of plc~ g la~ A1~1 boards,
15 sheets or articles -- useful as partitions, shelves, cou"l~.lo~s and bathroom vanities -which is
more eco..l~..ie~l and less labor-intencive than eYictin~ methotlc The present method also
enables a consumer to purchase standard size l~...il.~t~d boards, sheets or articles, customize
the shape of the l~min~te for the con~m~r'S individual use, and join the articles to provide a
finished look without the need of professional ~ict~nee. One aspect of the invention
20 provides a method of m~nuf~ture of an article which comprises a substrate and a plastic
coating. The plastic coating may be an in situ polymerized thermoplastic or thermoset
material l~min~tf d to any rigid substrate but preferably a cellulosic product such as wood or
particle board. Where a mineral-like appearance is desired, the subject invention may utilize
the compositions disclosed in my earlier patent applications, which have the appearance of
25 natural stone.
SU~3 111 UTE SHEET (RULE 26)
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Another aspect of the invention provides a plastic edge piece which is ~tt~r.hed to the
exposed wood edges of the coated article of the present invention after being cut by the
consumer. Generally the plastic edge piece is made of the same plastic material as is
l~min~tecl to the substrate. The collsul-ler conceals the edge piece and seams between
adjacent coated boards by applying additional plastic m~t.o.ri~l in liquid form. After curing,
the area of the applied plastic is then sanded for smoothness.
The present invention also provides a method for producing coated ~ul~ tes and
l~min~tes in which the surface smoothness and ~pedl~lce can be controlled to any desired
form. The present invention is particularly useful for the production of l~min~tes comprising
a surface layer of a highly filled thermoplastic or thermoset resin having a mineral appearance
on a rigid support.
The subject invention also has several economic advantages. First, it uses existing
machinery, namely l~min~ting or co~ ssion molding machines. Second, the product is
m~ .r~ ...Gd in a way to ...i~ i7e the labor involved in cu~lollli;~illg the articles and
s~nrling. Third, the l~nin~tes are made without the use of solvents which can constitute an
20 environmental hazard unless expensive l~eca~tulh.g techniques are used.
Brief D~ lion of Drawinps
Figure 1 illustrates the use of a 4' x 8' x 518" particle board as the substrate in the
l~min~te using 1/2" x 0.07" cardboard strips to form the gasket (2) which is preferably stapled
25 (3) to the board. Channels (4) allow excess casting resin to flow from the mold.
Figure 2 illustrates the molding process of this invention in which a thin plastic film
(6) is stretched over a shim or platen (5) of a molding press. The flowable casting or coating
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5 resin (7) is placed on top of the film (6) and if desired can be smoothed using a doctor blade.
The substrate (8) with the gasket (9) ~ttaçll~d is lowered on the spread resin (7) and the
assembly is co~llpl~ssed between the platens (5). The assembly is then heated to cure the
resin and adhere the resin to the substrate.
Figure 3 illustrates the process of the present invention in which the casting resin is
lO applied to both major surfaces of a substrate. Thus in an addition to the film (6), resin (7) and
gasket (9) attached to the substrate (8) a second gasket (10) is ~tt~.hÇd to the opposing major
surface of the substrate (8) to contain the second application of resin (1 1 ) on top of which is
stretched the plastic film (12) in contact with the platen or shim (5) ofthe molding press.
Figure 4 illustrates a l~min~te (1) COlll~liSillg a board (16) with surface coatings on
15 opposite sides (17) to which is ~tt~clled an edge piece (18) pre-cast from the same
composition as the coating, by means of dowels (19).
Figures 5, 6 and 7 show edge pieces in cross section fini~hed in various shapes by the
customer or pre-fini~h~l by the producer prior to attaehment to a ~ubsll~le.
20 Summary of tbe Invention
The subject invention provides a method for producing a pr~folllled, l~min~ted article
having a desired surface appearance which comprises cont~sting a substrate with a curable
plastic material in a liquid or semi-liquid state, said plastic material being held in place by a
gasket or spacer and being in contact with a flexible film, m~ irlg the contact between the
25 substrate, plastic material and the flexible film under conditions such that the plastic material
hardens and adheres to the subsllal~, and recovering a 1;....i..;.~ed article having the surface
appearance of the flexible film. The present invention also relates to l~min~tes having a
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S smooth mineral surface al)pe;~lce.
The invention further concerns a plastic edge piece which may be cast separately and
attached to the exposed edges of the l~min~ted article and which has the same appearance as
the plastic l~min~te
10 Detailed I)esr ;IJtion of the Invention
The present invention is based on a coll.pression molding process for the m~nllf~ctllre
of a l~min~tçd article which comprises forming a layered structure of a thin flexible film, a
polymerizable coating resin or simi}ar flowable coating material, retained in the structure by a
compressible gasket, and a substrate, the casting resin being present in sufficient quantity to
15 fill the cavity created by the gasket, the substrate and the film, applying ~ressul~ to the
structure and thereafter curing the casting resin or coating material to obtain a l~min~te of
substrate and cured casting resin or coating material having the surface appearance of the
flexible film. If desired and at times necessary to prevent warping of the substrate during the
molding process, a second liquid coating resin or coating material is applied to the opposing
20 surface of the substrate again held in place by a gasket. The coating resin can be the same or
dirr~lellt m~teri~l from the one applied to the first substrate. If desired another film is
interposed between the liquid coating and the platen of the press.
Once in place in the molding press the liquid casting resin or coating material, gasket
and substrate are ~les~ ;7çcl and the coating m~teri~l iS polymerized to completion, normally
25 by heating the coating material to a~ilivale the further polymerization. The res-llting l~rnin~te
is removed from the press, together with the film which can be retained on the l~min~te for
protection against surface scratches and gouges. Removal of the film provides a coating that
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5 duplicates the surface characteristics of the film and in this way one can obtain l~min~tPd
structures with surfaces that require no further working for the intPtlrled use.
The present invention also includes the l~nin~te made by the process of the present
invention and particularly l~min~te having co~tin~,C which contain greater than 30% by
weight of the coating of a immi~cjhle particulate filler to provide a smooth mineral
1 0 appearance.
The coating employed in the present invention can be a pre-polymerized liquid
thermoplastic or thermoset resins. Suitable pre-polymerized or partially polymerized
thermoplastic resins include acrylic resins such as polymethyl methylmethacrylate, and
methyl methacrylate copolymers such as are obtained by copolymerization with alkyl
15 acrylates, acrylic acid, methacrylic acid, styrene, and acrylic polyesters. Preferably however
the coating or casting resins employed in the present invention are thermosettable polymers
such as unsaturated polyesters, epoxy resins, polyurethane resins, crosslink~hle acrylic resins
and cro~link~hle styrene resins. The prepolymerized resins are employed in liquid form, the
liquidity resl~lting inherently from the low molecular weight of the resin or by solution in
20 monomer. of the thP~ sett-ble resins the prerell~d resins are the unsalu~led polyester resins
derived from the con-lPn~tion of an aromatic dicarboxylic acid or anhydride such as
isophthalic acid with one or more diols such as propylene glycol, neopentyl glycol, ethylene
glycol, or diethylene glycol in the presence of an unsaturated dicarboxylic acid or anhydride
such as maleic anhydride. The prepolymerized ullsalul~ted polyester is then dissolved in a
25 vinyl monomer such as styrene to form the liquid coating composition. Li4uid u-lsalulated
polyesters which can be cured by further polym~ri7~tion to form tough solid coatings are well
known in the art, any of which can be used in the present invention as coating materials. The
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- 6 -
5 resin, including any filler should have a fluidity at room tel.lpe.~lu.c adequate to fill the
cavity created by the gasket, the substrate and the film in the press and also in the event of
any excess, flow out of the mold through the ch~nn~!c provided in the gasket. Coating
compositions having viscosities in the range of 500 to 40,000 centipoises are suitable in the
process of the present invention.
As indicated, the casting resins or coating compositions employed in the present
invention are p~crc,~bly filled resin co-..posilions which give the coating an inol~lic mineral
surface appearance. Fillers employed in coating compositions to give surfaces having a
mineral appearance are well known in the art, having been described in my own patent, U.S.
Patent No. 5,304,592, Nogi et al U.S. Patent No. 5,034,377, and Buser et al U.S. Patent Nos.
4,085,246 and 4,159,301, the te~hingc of which are hereby incorporated by reference.
Particularly p~crc -cd fillers which give rise to a granite surface are separately ~ ,d
thermoplastic or thermoset resin composites co~ il-g evenly distributed inorganic
particulates. Such composites are then crushed and pulverized to a desired particle size for
inclusion in the coating composition. As disclosed in these references, the same type of resin
20 employed as a coating or casting resin can also be employed to form the filler. The plerellcd
fillers employed include particulates of thPmoset polyesters and/or acrylic resins col~ llg
such powdered illOlgal~iC materials as talc, silica, gypsum, powdered glass, clay, silicates and
particularly ahlmin~c including ~h.. i.. ll trihydrate. The fillers can be employed over a
wide concentration range from 2% to 70% by weight of the total coating composition but are
25 preferably employed in the range of 30% to 50% by weight of the total coating composition.
The casting resin or coating composition usually also COIll~lillS a catalyst which
initiates or accelerates the further polymerization such as a peroxide or similar free-radical
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initiator. Additionally the coating composition may also contain pigments, u-v light
stabilizers, antioxidants, coupling agents and mold release agents.
The flexible film employed between the platens of the press and the casting resin or
coating composition provides its surface characteristic to the ree~ ing l~min~te Generally
speaking it is desired to produce a l~min~te having a smooth surface that does not require
further fini.ching. Such finish is ~ccQmplished by having a thin flexible plastic film which
does not adhere to the l~min~te or only adheres slightly so that it can be easily removed from
the l~min~te but still adheres sufficiently to serve as a protective layer prior to use of the
l~min~te. Plastic films useful in the process of the present invention include polyolefin films,
polyvinylidene chloride films and preferably polyester films commercially available under
the tr~ n~me "Mylar."
The gasket material can be any solid material including metal, plastic or wood.
Preferably, however, the gasket material can be controllably coll~rcssed to a desired
thickness by the application of p,c~u, c used in the molding process. Materials that exhibit a
10% or greater reduction in the molding process have been found to be suitable. One
particularly preferred m~terial is cardboard since it can be readily cut to provide the gasket
and also can be complessed to the desired thickness considering the limits of its
con.plessibility. It also with~t~nfl~ any tcnll)cl~luie enco~l~e,cd in the molding process.
Hard rubber, elastomeric polyolefins and flexible polyurethane foams are also useful as
g~ eting m~t.o.ri~l as are many composites made from resins and cellulosic fibers.
The ~ubsl~le to which the coating is applied can be any semi-rigid or rigid m~t~having a surface providing adhesion to the coating or casting resin composition. In general
the process of the present invention is used with cellulosic type of material, such as solid
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5 wood boards, plywood, balsa sheets, particle boards and related composites co~ g
cellulosic fibers. other substrates or cores for the 1~min~te~ of the present invention include
high density polyurethane foam, honeycomb structures of reinforced cardboard, fiberglass or
carbon fiber reinforced sheets and similar structures. Where the ~ubsll~le is not rigid enough
to support the coating as produced in the present invention without warping, it may be
10 desirable to apply a similar or different second coating on the opposig surface of the
substrate which can be applied in the same way as the first coating such as illustrated in
Figure 3.
The size of sheets employed is only limited by the size of the molding equipment
employed and includes, in addition to the 4' x 8' already described sheets, dimensions from
less than l' to 12' or more.
The process of the present invention can be con~ cte-1 in any of the commercially
available co~l-plession molding presses and p~c~e,ably in one that provides for heating ofthe
platens to raise the telllpcl~lul e of the coating layer to allow for rapid curing. Generally
spe~'-ing, it is desired to heat the coating composition to a temperature within the range of
70~ to 300~ F. The pl~ Ul~S employed may vary, but generally speaking it is not necess~ry
to use ~res~ules in excess of l 00 psi. The process is contin11ed for a time adequate to
polymerize subst~nti~lly all of the polymerizable ingredients in the coating or casting resin.
In place of using a second coating on the opposing major surface, the rigidity of a
substrate or core can also be enh~nced during the molding process by 1~min~tin~ the opposing
surface of the substrate to an additional sheet comprising a composite of a partially cured
resin and a fibrous material in which resin cures and adheres to the substrate during the
molding process.
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In some inct~nceS, particularly where the l~nin~teS of the present invention areintenrled to be used as countertops, it may be desirable to provide an edge coating for the
l~min~te Such edges can be provided in several ways such as by spraying, brushing or
otherwise coating the edge of the board with the same composition as was used in forming
the l~min~te or there may be used a pre-cast edge or nose strip which is attached to the edge
of the l~min~te by means of dowels or similar devices as illustrated in Figure 4. If desired,
any visible seam between the l~ e and the edge or nose strip can be additionally coated
so that the seam is hidden. In order to ~ , uniformity of al)pea~ ce and plupc~lies the
edge piece should be cast from the same composition that is employed for the surface layer of
the l~min~te
The present invention is further illustrated, but not in any way limited, by thefollowing specific embodiment of the invention.
Over the top of heatable platen of a commercial molding press large enough to
~ccc,....-.odate a 4' x 8' sheet is stretched a two mil commercially available polyester film.
Using a doctor blade, a flowable casting resin having a viscosity of 20,000 centipoises at
room temperature (as measured on a R.V.F. 100 Brookfield Viscosimeter using a Springdale
#6 spindle at 100 rpm) is evenly spread to a thickness of slightly more than 1/16". The
particular flowable casting resin was a cornmercially available ul~saLul~ted polyester
composition sold as "Granicoat". The ~l~alulated polyester contained a polymerized resin
filler designed to give the coating composition a granite al)pea,~lce. Preparation of such
filler is described in my co-pending application SN 08/051,627 filed April 22, 1993 which is
hereby incol~o,at~d by reference.
To a 4' x 8' x 5/8" particle board are stapled along the edges of the board 1/2" wide
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- 10-
5 0.07" thick cardboard strips forming a gasket to contain the casting resin as illustrated in
Figure 1. Channels are provided at the comers of the gasket to allow excess casting resin to
flow from the mold. The gasketed surface of the board is placed in contact with the spread
resin as illustrated in Figure 2.
The assembly is subjected to a p.~ule of approxim~tely 100 psi and the platen in
10 contact with the resin is heated to a tel,.?e,~lur~ of 200~F. which is i~ .ed for a period of
5 minlltes thereby fully curing and adhering the coating to the board.
The resulting l~min~te contains a 1/16" layer of smooth surfaced granite like m~t~ri~l
firmly attached to the particle board with the polyester film adhered to the surface of the
co~tin~. The film can be mechanically removed at any time and pler~l~bly is retained to
15 serve as protection for the surface until final use of the board.
The uncoated edges of the particle board can be sawn offor spray coated or brushed
with the casting resin to provide a fini~h~cl article. Preferably the uncoated edge portions are
sawn off and replaced with a doweled edge piece (illustrated in Figure 4) cast from the same
composite as is used for the surface of the l~min~te.
