Structural panel and process of making same

FIELD OF THE INVENTION

This invention pertains to building material and, more particularly, to an improved decorative or ornamental panel and the process for its preparation.

DESCRIPTION OF THE PRIOR ART

The panels of the present invention serve a similar function as concrete ornamental panels which are presently in common use in providing exterior building facings. However, it has been found that the panels of the present invention are superior to concrete panels in several respects. The usual concrete facing panel is, by the very nature of the material, heavy and brittle, thus making it extremely difficult to handle, not only when transporting it, but when affixing it to a building. Secondly, concrete panels have a high tendency to chip and crack or to shed their decorative surfacing, and thus there results a great deal of wastage, or a poor appearance after a relatively short period of use. Thirdly, concrete requires a long cure time to obtain its maximum strength, thus increasing the cost of manufacture, and often causing delays in building construction. The building industry has experimented with many materials in an attempt to reduce these difficulties, but has been unable to devise a suitable exterior building surface.

SUMMARY OF THE INVENTION

The present invention overcomes these and other problems of the prior art by providing a facing panel which is functional, durable, strong, light weight and ornamental, and which is crack resistant, has a strong bond between the substrate and facing material, and cures quickly for use within a short period of time.

An object of the present invention, therefore, is to provide a construction panel for curtain type walls which is ornamental.

Another object is to provide a construction panel which has high-strength characteristics.

Still another object is to provide an ornamental panel which has good weather-resistant and insulating qualities.

Another object is to provide a panel that can be prepared in a medley of shapes and sizes.

A further object is to provide a construction panel which can be manufactured relatively inexpensively and without forming apparatus.

Another object is to provide a method for preparing a decorative or ornamental panel which is pleasing to the eye and has high-strength characteristics, good insulating qualities, waterproof, weather resistant and can be manu25 factured relatively inexpensively and in a variety of shapes and sizes.

These and other objects are attained by the practice of this invention which, briefly, comprises the steps of saturating a fiber-board with a resin, curing the board, coating or laminating at least one surface with a resin containing implanted or intermixed fiber rovings, embedding decorative material in the surface resin and curing the panel. This method produces a unitary panel structure which may be used on curtain type walls, either interiorly or exteriorly of the building, in any desired configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features and objects of the invention will be more fully understood from the following specification and claims, taken with the accompanying drawings in which:

FIGURE 1 is a cross-sectional view of the basic core fiber-board;

FIGURE 2 is a cross-sectional view of the basic core fiber-board saturated with a resin;

FIGURE 3 is a cross-sectional view of the cured resin saturated fiber-board which has been tongued and grooved;

FIGURE 4 is a plan view of joined saturated core boards;

FIGURE 5 is a cross-sectional view of a joint formed by joining sections of core board together;

FIGURE 6 is a cross-sectional view of the resin coated or laminated core board;

FIGURE 7 is a cross-sectional view of the resin coated or laminated core board with the decorative material embedded in the resin;

FIGURE 8 is a perspective view of the finished panel; and

FIGURE 9 is a cross-sectional view of a cap panel containing a flashing or roofing reglet.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The process for preparing the decorative panel of the present invention comprises saturating the core fiberboard 1 illustrated in FIG. 1 with a polyester resin 2, as in FIG. 2, and curing the resin. The cured saturated board 3 may then be provided with a groove 4 and a tongue 5, as in FIG. 3, for the purpose of joining a plurality of boards 3 together to form a large panel. The boards may be adhered together by use of an adhesive 6 and, optionally, a screw 7 traversing the tongue and groove joint 8 to form an extremely strong connection. After the proper number of treated boards have been fastened together to form the desired size and shape of the panel, anchoring means may be attached to at least one surface should this be desired. The outer, or face, surface of the joined boards 3 is coated or laminated with a polyester resin 9 containing fiber rovings 10. The decorative material 11 is applied to and is at least partially embedded in the polyester resin coating 9. The polyester resin 9 is cured and any excess decorative material 11 is removed. The finished panel 12 is light-weight and decorative, and has all the desirable features set forth hereinabove.

The basic core panel may be any porous fiber-board, such as the bagasse core board manufactured by Fibrelite Corporation. Other boards of suitable characteristics may be used.

The bagasse core board preferred has a density of about 45 to about 50 pounds per cubic foot. The amount of polyester absorbed by the bagasse board increases the density by about 65 to 85% of the original poundage.

The polyester resin which may be used for saturating

3,474,584 the basic core board and for the coating or laminating process is any polyester resin which is compatible with the resin employed in the manufacture of the board. Polyester of a dicarboxylic acid such as terephthalic acid, isophthalic acid, etc. and a glycol such as ethylene glycol may be used. However, isophthalic polyester resin is preferred. Other suitable resins will be apparent to those skilled in the art.

The staurated board is cured by any known heating method such as heating ovens, heating rolls or belts, infrared heat, or other methods. Direct infra-red heat is preferred for both curing steps because of its ease in utilization.

A plurality of polyester resin saturated bagasse core boards may be joined together to form a large panel. After the cured saturated resin boards are tongued and grooved, an adhesive such as epoxy is applied to the edges to be joined. The boards are abutted together and for additional strength screws are used. The screws, if employed, traverse the tongue and groove portion of the joint, as described with respect to FIG. 5. However, any other convenient method of joining the boards together to prepare a large panel may be used.

The basic bagasse core board may be cut or produced in any desired length or width. However, for ease of handling it has been found that a maximum size of 5 feet wide and 20 feet long is preferred.

The anchor means which may be applied to at least one surface of the panel for use in attaching the panel to a building structure, may be angle irons, hooks, brackets, bolts or any other adaptable hardware. The anchoring means are attached to the panel by any convenient method such as elevator bolts, screws, etc.

The fiber rovings which may be incorporated in the polyester resin to the extent of about 20 to 40% may comprise materials such as mineral and/or synthetic fibers. Fibers most commonly used for such purposes are glass, cotton, wool, cellulose, asbestos, hemp, etc. However, in the present process, fiber-glass rovings are preferred.

Examples of the decorative material which may be embedded in the polyester resin surface coating are aggregates, such as silica flour and silica granules, stone pebbles, stone chips, inorganic pigment, and the like. These materials will vary in accordance with the texture and appearance desired in the finished wall structure.

The panels of this invention may be used in any area of construction where a decorative surface is desired, such as on the exterior of a structure, the interior, roof, ceiling, floors, etc.

The following example illustrates the best mode contemplated in the manufacture of the decorative panels.

EXAMPLE

A special run bagasse core board in various sizes as manufactured by Fibrelite Corporation, Vacherie, La., having a density per cubic ft. of 47 lbs. was utilized in the making of decorative panel of the invention. The board was saturated with isophthalic polyester resins. This application brought about an increase of density to the board of 75% of original poundage.

The isophthalic polyester resin which was absorbed by the core fused with the thermo-plastic binders utilized in the manufacture of the raw bagasse core. The increase in density brought about through this saturation enhanced the overall strength factors of the basic core. The core was then placed under direct infra-red heat to bring about proper curing of saturation resins.

The cores were cut to the desired length and width, which in the present case was about 5' wide x 20' long maximum size. The edges of the cores were either tongue or grooved. Upon completion of the tongue and groove operation the cores were joined together, utilizing a low molecular weight epoxy resin for adhesion purposes and the tongue and groove were through screwed, thus bringing about an extremely strong connection. Where the two cores were joined together the actual joint was stronger than any other portion of the panel due to the reinforcing brought about by the addition of the epoxy glues. Various sizes and shapes of the core products were fabricated in the previously mentioned manner to bring about a panel core having the desired overall size.

A steel angle was secured at the top of the core running horizontally on the panel by drilling holes through the core and inserting elevator bolts through the holes and the angles. The holes were drilled 16 on center. An identical angle was attached in the same fashion to the lower part of the core panel.

A lay-up course of isophthalic polyester resin containing 25 to 35% fiber-glass rovings was laminated to the outside surface of the basic core panel to a total thickness of Vie. The resin used was a casting resin having the following characteristics: Type—flexible; dibasic acid-—PA; viscosity² (cps. at 77° F.)—500; pounds per gallon—9.30; specific gravity at 77° F.—1.117; styrene content—40%. The preceding are solution characteristics. Curing characteristics: 70° F.—jell time (minutes)—16.0; peak exotherm (° F.)—290; curing rate— medium. Following properties: Heat distortion (°F. at 264 p.s.i.)—156; Barcol hardness—42, izod impact (unnotched) (ft. lbs./in.)—2.2; flexural strength (10³X p.s.i.)—15.0; volume shrinkage—7.80. Upon completion of the plastic lamination, the decorative material was applied by first laminating on the panel a 14 thick (min.) exterior plastic matrix, consisting of the following formulations: Chevron Chemical Company Resin #5765, 139.5 lbs.; pure white silica flour, 200 lbs.; silica granules divided into equal measurements of #1, 2, and 3 size, 300 lbs.; and inorganic pigment (dispersion color paste), dispersed in a special light stabilized vehicle in required poundage (depending on color desired) averaging 14 of 1 lb.

As the laminate was troweled onto the panel, aggregates of various sizes and types were pervaded and pressed into laminate. The panel then was infra-red cured. Upon completion of curing (approximately 1½ hours) excessive stones (those not firmly embedded into matrix laminate) were removed from the panel by sweeping and vacuuming. Panel was then completed.

A unique feature of the invention is the ease with which a parapet, or cap panel, such as that illustrated in FIG. 9 can be constructed. As shown in this figure, the topmost panel 15 on the building structure is formed with a narrow backing panel 16 fastened to it by any suitable means, such as an epoxy adhesive. The core board for the backing panel is formed in the same manner as the core for the facing panel, and is provided with a slot 17 for receiving a roofing reglet, or flashing, 18. The backing panel extends over the top roof deck 19 of the building, with the flashing 18 serving its usual function of sealing the joint between the parapet and the roof.

After the backing panel is attached to the facing panel 15, the layer of resin 9 is applied to panel 15, and is extended up over the top of the parapet in a double thickness, as illustrated at 20. The facing material 11 is then applied to the panel 15, but since its primary function is that of decoration, it need not be applied to the upper and back portion 20.

The cap portion illustrated in FIG. 9 is preferably used with a construction utilizing facing panels made in accordance with the present invention, but it will be apparent that they could be used as separate units in conjunction with other facing materials.

Thus, there has been described a new and useful prefabricated structural panel for buildings of various types, the panel being light in weight and durable. The panel has been successfully used on exterior surfaces of buildings, and has been shown to be inexpensive to make, strong, and easy to install. Because of the lightness of the material and simplicity of installation, an entire wall of

3,474,584 a four-story office building has been erected in a single working day.

A less apparent advantage of the present invention is that the lightness of the panels, which are about onethird as heavy as masonry construction, allows consid- ₅erable savings in the basic building concrete and steel framing, a savings which in some instances may be enough to pay for the purchase of the wall panels for the building. In addition, the weather-resistant feature of the panel eliminates the cost of waterproofing the exterior surface of the building, a process that is required approximately every five years with masonry. Because of the use of large panels of insert plastic in which marble or other chops are embedded, water cannot penetrate the panels. The only possibility of leakage is at windows and 15 other openings, where there must be caulking.

The invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and 20 scope of the invention hereinbefore described and as defined in the appended claims.