CA1036778A - Molded fibrous panel with finished surface - Google Patents

Abstract

A B S T R A C T

A coated, decorative panel or tile of molded fibrous material and a method of making the same. A pad of preferably glass fibers held together by a binder in an uncured state, is compressed and heated in a matched metal contoured mold to the desired permanent shape, after which a finishing coat is applied. The resulting panel has an obverse face with a high fidelity reproduction of the mold surface. The panel fibers are heterogeneously arranged, being mostly parallel to the panel's contoured surface, with some lying angularly thereto. The surface appearance is improved by positioning a non-woven fibrous sheet on the uncured pad before molding. The non-woven sheet and the pad are placed between two mold halves, one of which is contoured to form a front face of the panel, with the non-woven sheet side of the pad being adjacent the contoured mold half. The mold halves move together, com-pressing the fibrous material, while heat is applied to bend the fibrous layer.
The mold halves are then separated, and the contoured panel removed. The non-woven sheet now conforms to the contoured surface of the mold along with the fibrous pad, and also bridges more open portions of the panel's surface while masking non-uniform areas thereof.

Description

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This invention relates to a coated, decorative panel or tile, and particularly to such a panel or tile having a fibrous sheet on an obverse sur-face thereof with a finish coating material applied thereto.
Molded decorative panels or tiles of mineral fibers and particularly glass fibers are known in the art and are becoming more popular. Tiles of this nature are shown and disclosed more fully in Jones et al U~S. Patent 3,49~,771 (issued Feb~ 3, 1970). Such tiles can be made in a variety of designs particularly because the glass fibers more fully assume and reproduce the contour of the design as incorporated into matched-metal forming dies or molds~ In other words, the glass fibers achieve a higher fidelity in repro-ducing the design of the mold surface than is possible with other fibers, such as wood fibers.
After the panel is molded and the binder cured, it is desirable to cover it with a suitable coating material, such as paint, for a final decor-ative effect. The glass fibers in the product, however, are heterogeneously disposed with most parallel to the surface of the tile but with some angularly positioned with respect thereto, with the spacing of the fibers also varying, depending on the degree of compaction, In addition, the molded tile or panel is subject to variations in the amount of binder present.
These factors all affect the degree of absorption of the paint into the panel. Consequently, when the coating material is applied to the surface, it soaks in at different rates and produces a non-uniform, rather mottled appearance. This can be offset to some extent by using substantially more paint than otherwise required to flood the surface and fill in the more por-ous portions. However, the details of the surface pattern thereby tend to be obscured and the flooded portions produce a less flat surface appearance, which is generally not as desirable for a decorative ceiling panel or tile, for example.
Also, in the production of such panels the binder used with the fibers tends to stick to the mold and build up thereon, requiring time-consum-ing cleaning. ~ ~

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In a broad aspect, the invention resides in a rigid, molded ceil-ing tile comprising a molded fibrous body of fibers held together in a permanent shape by a cured binder, said body having an obverse surface and a back surface and having means for affixing the tile to an overhead support with the obverse surface facing downuardly, a heat-softened plastic sheet on the obverse surface of said body and only partially penetrating the ibers of the obverse surface o the body to affi~ the sheet to the body, and an outer fibrous layer which is substantially thinner than said fibrous body on said plastic sheet with portions of the plastic sheet penetrating through the fibrous layer to provide a finish0d outer surface on the fibrous body, with fibers of the fibrous layer being visible at the finished surface.
In a further broad aspect, the invention comprises a method of making a product with a finished surface thereon, comprising providing a body of fibrous material held together with an uncured binder with a plastic layer thereon and a non-woven fibrous layer thereover, and applying heat and pressure to the non-woven layer to form the body and layers into a pre-determined shape and to soften the plastic layer to cause it to adhere to the body and to flow at least partially through said non-woven layer to form the finished surface.
More specifically, it has been discovered that a facing sheet of a non-woven, cloth-like, draftable material can be applied to the pad or pelt of uncured fibrous material before being placed in the mold to overcome the above disadvantages. The sheet can be applied to the fibers directly during forming of the pad so that no additional labor is required, or can simply be laid on the pad prior to being placed in the mold. The sheet assumes the configuration of the mold surface with a high degree of fidelity when the pad is compressed between the matched-metal mold sections. The sheet thereby forms a web or bridge over the less dense portions of the resulting product to provide a substantially more uniformly absorptive sur-face to which the coating material is applied. The sheet also masks irregularities or discolorations in the mold pad or pelt and thereby enhances the final decorative effect of the panel or tile.

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The use of the sheet on the product reduces the amount of coating material required to produce a satisfactory finish and at the same time improves the uniformity of the appearance of the product. A uniform, flatter finish is thereby achieved on the tile or panel due to the reduced amount of paint and such finish is generally preferred for ceiling tiles and the like.
Further, the sheet acts as a parting ngent between the front face o the pad and the mold surface to substantially eliminate binder build-up in the mold and the otherwise required frequent cleaning. The handleability of the tile is also improved, particularly at the edges of the tile where the fibrous sheet can cover glass fibers otherwise projecting at such edges.
As an alternative to painting the surface of the panel, which requires a separate operation, it has been discovered that a coating of plastic material can be applied during the molding operation. A facing sheet, which constitutes a plastic, preferably vinyl, layer with a fibrous, prefer-ably non-woven, layer thereover, can be applied to the pad or pelt of the uncured fibrous material before it is placed in the mold, to provide a final, finished surface on the molded product, without further finishing steps being requiredO The facing sheet can be in the form of two separate layers, one of them vinyl and one of the non-woven fibrous material, or it can be a single combined sheet of these.

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Still further, it is conceived that the non-woven can be impregnated with a plastic material that will soften under the heat of the molding operation and form the finished surface~ In any event, the facing sheet is disposed so that the fibrous layer is on top of the plastic layer, the latter being between the fibrous layer and the surface of the fibrous pad. ~hen heat and pressure are applied by the matched metal dies, the plastic layer softens sufficiently to adllere to the ibrous pad and at that same time to penetrate the ibrous layer to provide a finished surface on the molded product. The plastic layer preferably does not completely hide the fibrous layer, however, so that an attractive textured appearance is achieved for the final, molded products.
The finished surface constituting the combined plastic and fibrous layer forms a web or bridge over the less dense portions of the molded product to provide a substantially more uniform surface, masking irregularities or discolorations in the product and enhancing the final decorative effect thereof The finished surface also exhibits a de~ree of porosity for acous-tical benefits and yet provides a good light reflectivity. The non-woven sheet also acts as a parting agent between the plastic layer and the surface of the die or mold to substantially eliminate any sticking or build up on the mold of the plastic or binder from the fibrous pad, which otherwise can occur, requiring frequent cleaning of the mold or ruining the appearance of the fin-ished surface. The handleability of the panel is also improved, particularly at the edges thereof where the facing sheet can cover glass fibers otherwise projecting at such edges.
It is,therefore, a principal object of the invention to provide a decorative panel or tile having a more uniform, improved appearance on the obverse face thereof and a method of making the same.
Other objects and advantages of the invention will be apparent from the following detailed description of it, reference being made to the accom-panying drawings, in which:

Figure 1 is a schematic, fragmentary side view in elevation of afiber-forming line which can be used to produce a pad or pelt from which -77t~ .
a decorative panel according to the invention can be molded;
Figure 2 is a schematic view in perspective of the molding apparatus for producing a decorative panel according to the invention;
Figure 3 is a somewhat schematic view in perspective of a pad or pelt made with the apparatus of Figure 1 and ready for insertion into the molding apparatus of Figure 2;
Figure 4 is a somewhat schematic view in perspective of a decorative panel or tile made according to the invention;
Figure 5 is a greatly enlarged, fragmentary, schematic view in cross section, taken along the lint 5-5 of Figure 4;
Figure 6 is a view similar to Figure 5, but further showing a layer of coating material on the panel;
Figure 7 is a schematic, fragmentary side view in elevation of a fiber-forming line which can be used to produce a pad or pelt from which a decorative panel with vinyl surface finish can be molded;
Figure 8 is à somewhat schematic view in perspective of the pad made with the apparatus of Figure 7 and with a facing sheet embodying the invention applied thereto, ready for insertion into the molding apparatus of Figure 2;
Figure 9 is a greatly enlarged view in cross section taken through the pad of Figure 8;
Figure 10 is a view similar to Figure 9 but with a slightly modi~fied facing sheet on the pad; and Figure 11 is a greatly enlarged view in cross section taken through the pads of Figures 9 and 10 after the molding process.
Referring to the drawings and more particularly Figure 1, a fiber-forming line 10 can be used to produce a pad or pelt according to the invention, with substantially no additional labor being required over and above that employed to make a conventional pad. Accordingly, glass is melted in a tank 12 and supplied through a forehearth 14 to a fiber-forming unit 16. Fibers indicated at 18 are attenuated from the unit and move downwardly, the fibers 18 being deposited on a belt 20 of a conveyor 22. Binder can be applied to 1C~3677~
the fibers in a forming hood 24 by suitable spray applicators 26. The fibers are gathered on the belt with the aid of a vacuum chamber 28 located below the upper run of the belt 20 This basic apparatus is well known in the art and will not be discussed in detail~
In accordance with the invention, a non-woven sheet 30 is supplied onto the upper run of the belt 22 from a supply spool 32. The sheet prefer-ably is porous and does not seriously inhibit the function of the vacuum chamber 28 in collecting the fibers on the belt 20 The fibers 18 with the binder applied thereto are deposited directly on the sheet 30 as it moves toward the right, as viewed in Figure 1 The sheet thereby can be adhered directly to the fibers through the binder, with the fibers also being adhered to one another by the binder The sheet 30 and a resulting layer 34 of the fibers 18 are then carried between two conveyors 36 and 38 which are spaced apart a predeter-mined distance to place the surfaces of the fiber layer 34 in smooth, parallel relationship. A pad 40 for the mold charge is thereby produced, consisting of the sheet 30 and a smooth, uniform layer 42 of the fibers 18 adhered thereto.
The pad 40 can then be carried away by an exit conveyor 44 to a point where it can be cut to predetermined shape and size, Alternately, the pad can be stored on a reel and transported closer to a point of final use, if desired, at which time the pad can be cut to the proper size, A final pelt or pad 46 (Figure 3) serving as a mold charge results, consisting of the layer 42 and the sheet 30 cut to a desired size. In this state, the binder is not cured so that the pad is deformable, but the binder still provides structural integrity for the pad.
Of course, rather than applying the sheet 30 to the layer 42 on the production line 10, the layer 42 can be formed without the sheet which can then simply be laid on the top surface of the layer 42 prior to it being placed in the molding apparatus.
Molding apparatus 48 of Figure 2 is representative of apparatus for making the panels or tiles by matched-metal die compression molding. The apparatus 48 includes a base 50 with upwardly extending column or ways 52 on which is slidably mounted a head 54. The head 54 is moved vertically by -1036~7~
a fluid-operated actuator 56 of a suitable design, suitably supported overhead.
A lower mold half or die section 58 is mounted on a backing plate 60 and supported on the base 50 A matched upper mold half or die section 62 is mounted on a backing plate 64 and affixed to the lower surface of the head 54 by suitable fasteners~ Dowels or other suitable means can be employed to place the mold halves 58 and 62 in accurate registry when the head 54 is moved downwal~dly by tlle actuator 56~ The upper mold half 62 has a trim lip or ridge 66 wllich moves into contact with a corresponding surface of the lower mold 58 to place the surfaces of the two mold halves in a predetermined spaced relationship when the mold halves are fully closed~ The pad 46 is somewhat larger in area than the tile or panel to be made so that portions thereof extend beyond the edges of the final product and are cut off by the trip lip 66 of the upper mold half 62~ The pad also is much thicker than the distance between the mold halves when closed~
The design produced by the mold halves 58 and 62 can be almost unlimited. As shown in the specific example, the lower mold half 58 has corner angular projections or ridges 68 and a central large projection 70 which co-operate with corner angular recesses or grooves 72 and a central recess 74 in the upper mold half 62~ These produce a molded panel or tile 76 of Fig. 4, having corner angular projections or ridges 78 and a central projection 80 on an obverse surface 82 thereof. The tile 76 also has suitable flanges 84 formed at two opposite edges thereof by means of which the tile 76 can be affixed to a ceiling or other supporting surface, as is shown more fully in the afore-mentioned Jones et al U~S~ Patent 3,492,771 (issued Feb. 3, 1970).
The tile is compressed and densified between the mold halves 58 and 62, being in the order of 1/8 inch thick, compared with the pad 46 being as much as two inches thick~ The tile, made with glass fibers in the order of 0~00025-0~00035 inches in diameter, has an apparent density in the order of 15-35 pcf~ The binder is thermosetting and usually is a phenolic, present in an amount of about 15-20% by weight, on the average. Typically, the mold halves 58 and 62 are heated to a temperature of 500F for a period of 45 seconds to effect curing or polymerization of the thermosetting binder which binds the fibers together as well as the sheets 30 (Fig. 3) to the fibers. While the mold halves 58 and 62 are brought together under considerable pressure, the extent to which their surfaces move toward one another is limited by the trim lips 66 or similar projections, Consequently the pressure exerted by the fibrous layer 42 in pushing the sheet 30 against the surface of the upper mold half 62 is only in the order of lO`psi~
The fibers in the pad 46 tend to lie parallel to the main surfaces thcreof but otherwise are heterogeneously arranged. The high degree of com-pression of the pad 46 causes the fibers to tend to be parallel to the obverse surface or face 82 thereof and also to a back surface 86 (Figs. 5 and 6). How-ever, some of the fibers will be disposed at angles to the surfaces 82 and 86 and this will be particularly true of that portion of the surface 82 where a rather abrupt change in the surface exists, as at the projections or ridges 78. At such portions of the tile, the fibers will tend to assume the config-uration of the mold halves 58 and 62 initially but may be angularly disposed, particularly if there should be less binder at such areas than otherwise nec-essary to hold the fibers in the curved configuration, after the binder has been cured. The tile also may be thinner at the projection 78 and the fibers themselves may be spaced apart farther than at other portions because the cured configuration of the projection 78 may tend to spread or stretch out the fibers thereat. Compression of the fibers at such portions may also be less as a result of the surface configuration. Additionally, swirls or balls 88 of the fibers 18 sometimes tend to form in the hood 24 and are collected in the layer 42. The fibers of such balls tend more to lie angularly relative to the surfaces of the tile than do the other fibers. The binder in the pad 46 also is subject to rather wide variation in concentration or amount and causes a mottled appearance on the surface of the cured tile as well as a variation in apparent density.
All of these factors, namely the angular disposition of some of the fibers, the wider spacing or lighter density of fibers in portions of the tile, the balls 88 of fibers,-and the variation in the amount of binder, have an effect on the degree to which the finish coating material, such as paint or the like, is absorbed in the tile. Consequently, a mottled appearance results after the tile is coated. For example, with a light paint, the portions of the tile in which the paint has been absorbed to the greatest extent appear darker than other portions~ Greater uniformity in the appearance of the tile can be achieved by flooding the paint onto the tile to fill those portions into which the paint tends to soak. This, however, requires substantially more paint than would otherwise be needed and, further, tends to obscure some of the details of the d0sign of the tile and to produce a shinier surface at portions thereof.
The sheet 30 on the layer 42 overcomes the above problems and has other advantages The sheet 30 preferably is yieldable or stretchable in at least one direction to enable the sheet to conform fully, with a high degree of fidelity, to the contour of the upper mold half 62~ A highly effective material for the sheet 30 is made by a dry lay process in which the fibers tend to be orie~ted in a single direction in the sheet, Such a sheet tends to be particularly yieldable or draftable in a direction transverse to the fibers. The sheet can also be made by a wet lay process by which the fibers are more randomly disposed. Such a sheet, however, displays less yield or drape in any direction than the dry lay sheet. Preferably the sheet is made entirely of rayon fibers, with the sheet being from 3~1/2 to 7 mils thick and weighing from 1/4 to 3/4 ounce per square yard, and a binder must be used in the sheet which can withstand the temperat~res of the mold. Specifically, a satisfactory sheet consists of 100% rayon fibers bonded by an acrylic binder, having a thickness of 7 mils and weighting 15.8 grams per square yard. While it would not ordinarily be expected that the rayon fibers of the sheet 30 would withstand the temperature of up to 500F. of the mold, apparently the higher temperature tends to soften the rayon fibers and enables them to conform even more effectively to the surface contour of the upper mold half 62 as the com-pressed fibers of the layer 40 urge the sheet 30 toward the surface of the mold half 62. A resulting contoured sheet 90 thereby masks variations in the obverse surface 82 of the tile and bridges pGrtiOns where the tile tends to absorb more coating material because of the angular configuration of the fibers, ~03677~
or wider spacing thereof. The sheet also helps mask the darker and lighter areas caused by the variation in the concentration of binder and tends to level the degree to which the coating material soaks in due to variations in the amount of binder, the tile absorbing less coating material in those por-tions where the binder is more concentrated. Consequently a finish or decor-ative layer 92 of coating material can be achieved with greater uniformity in appearance and with about 20~ less coating material than the amount required when applied directly to the surface 82 of the tile without the sheet 90 thereon~ Portions of the tile thereby do not tend to be flooded and obscured by a heavy coating; a more uniform, flatter appearance is achieved without the shinier portions otherwise often res~lting when a heavy coat is used. The coating can be applied by any suitable means, including electrostatic spraying if the sheet 30 can be s~itably treated to carry an electrostatic charge.
It has also been necessary, when using the fibrous layer 42 directly with the mold halves 58 and 62, to clean the mold halves rather frequently because of binder or fibers, or both, from the pad 42 sticking to the upper mold half, particularly in the recesses 72 and 74 thereof. However, when the sheet 30 is used, it has been found that the sheet serves as a parting agent and enables the title to be removed from the mold halves more easily than heretofore, with the need for cleaning the mold halves also being reduced.
When the sheet 30 is applied to the fibrous layer 42 on the production line 10, the sheet 30 can act as a separating layer if the pad 40 is rolled onto a reel for storage prior to being cut and used. Consequently, the sheet 30 eliminates the need for paper to be used between the wraps of the pad material in the rolls.
Figure 7 shows a fiber forming line 10, similar to the one shown in Fig, 1, only used to produce a pad or pelt without the non-woven sheet already applied to the pad. The pad 46 produced by this process can be com-bined with a layer of plastic material and a layer of non-woven material to provide a finished surface in the molding operation. However, because it is desirable to place the plastic material between the fibrous pad and the non-woven layer, as discussed later, the non-woven sheet is not applied to the -~03677~
pad in the forming operation~ Since the apparatus of Figure 7 has already been described with reference to Fig~ 1, no further description is deemed necessary here.
From the fiber forming line 10, of Fig. 7, a final body in the form of a pelt or pad 46, cut to proper size for a mold charge, is shown in Fig. 8.
In accordance with the invention, a facing sheet 102 is employed on the pad 46, The facing sheet includes a plastic layer 94, specifically a vinyl one, in the order of 2 mils thick but with a range of thickness from 1 mil to 6 mils being suitable. The facing sheet 102 also includes an upper fibrous layer 30, preferably of non-woven fibers, rayon fibers having been found to be suitable for the purpose~ As such, the mold charge comprising the fibrous pad 46 and the facing sheet 102 is ready to be placed in a mold.
With the pad 46, the plastic layer 94, and the fibrous layer 30 under heat and pressure in the mold, as discussed above, the temperature causes the layer 94 to soften sufficiently to partially penetrate the fibers of the pad 46, as shown somewhat schematically in Fig. 11. This penetration, along with the curing of the binder on the fibers provides good adherence between the plastic layer 94 and the pad 46. Further, the softened plastic layer partially penetrates the non-woven fibrous layer 30 so as to be visible from the obverse side of the panel, but with fibers of the layer 30 still being visible to provide a textured, final, attractive appearance for the panel. The finished surface also exhibits a degree of porosity for achieving some acoustical benefits and at the same time provides a good degree of light reflectivity. This surface requires no further manufacturing steps or coating steps to complete the panel so that the cost thereof is correspondingly reduced from a labor standpoint. Further, no additional apparatus is required to produce the finished surface other than the mold itself, which requires no modification to accomplish this purpose. The combination plastic and fibrous layers are also effective to bridge discontinuities in the surface of the panel and to mask nonuniform areas thereof.
It would ordinarily be expected to place the plastic layer on top of the fibrous one for producing the finished surface. However, it has been ~03677B
discovered that by placing them with the fibrous layer on top, this layer protects the upper mold half from the plastic layer and prevents it from sticking to the mold half, thereby serving as a parting agent. Further, the temperature of the mold or press need not be reduced in order to protect the vinyl layer. Consequently, a lower temperature and a longer mold cycle are not necessary, as would otherwise be required with the plastic sheet on top.
Rather than employing the separate layers 94 and 30 for the facing sheet 102, a combined facing sheet 122 of Fig 10 can be employed This sheet 122 consists of a lower layer of plastic such as vinyl and an upper layer of non-woven fabric supplied as the single sheet 122 on the pad 46.
The plastic layer penetrates the fibrous layer when subjected to the heat and pressure of the molding apparatus 48 so that the final product appears similar to the final product as shown in Fig. 11, made with the facing sheet 102 con-sisting of the separate layers 94 and 30.
Various modifications of the above-described embodiment of the invention will be apparent to those skilled in the art and it is to be understood that such modifications can be made without departing from the scope of the invention, if they are within the spirit and the tenor of the accompanying claims.

Claims (9)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A rigid, molded ceiling tile comprising a molded fibrous body of fibers held together in a permanent shape by a cured binder, said body having an obverse surface and a back surface and having means for affixing the tile to an overhead support with the obverse surface facing downwardly, a heat-softened plastic sheet on the obverse surface of said body and only partially penetrating the fibers of the obverse surface of the body to affix the sheet to the body, and an outer fibrous layer which is substantially thinner than said fibrous body on said plastic sheet with portions of the plastic sheet penetrating through the fibrous layer to provide a finished outer surface on the fibrous body, with fibers of the fibrous layer being visible at the finished surface.

2. A ceiling tile according to claim 1 wherein said fibrous layer is a non-woven sheet.

3. A ceiling tile according to claim 1 wherein said plastic sheet comprises a vinyl plastic material.

4. A ceiling tile according to claim 1 wherein said fibrous body comprises glass fibers and said fibrous layer comprises heat-softened plastic fibers.

5. A method of making a product with a finished surface thereon, comprising providing a body of fibrous material held together with an uncured binder with a plastic layer thereon and a non-woven fibrous layer thereover, and applying heat and pressure to the non-woven layer to form the body and layers into a predetermined shape and to soften the plastic layer to cause it to adhere to the body and to flow at least partially through said non-woven layer to form the finished surface.

6. A method according to claim 5 characterized by combining said plastic layer and said non-woven layer prior to placing them on the body.

7. A method according to claim 5 characterized by applying the heat and pressure to the non-woven layer by placing the body, plastic layer, and non-woven layer in a mold between two heated die plates and moving at least one of the die plates toward the other.

8. A method of making a molded ceiling panel, said method comprising placing a body of refractory fibers held together by an uncured binder with a plastic layer thereon and with a non-woven fibrous layer over the plastic layer in a mold between a pair of heated die plates, and moving at least one of said die plates toward the other to apply heat and pressure to the non-woven layer to cure the binder and to form the combination into a predeter-mined, permanent shape and at the same time soften the plastic layer to cause it to adhere to the fibrous body and to flow at least partially through the non-woven layer to form a finished surface on said panel.

9. A method according to claim 8 characterized by combining said plastic layer and said non-woven layer prior to placing them on the body.