CA1042615A - Apparatus for preparing striped sheet material continuously - Google Patents

Abstract

IMPROVED APPARATUS FOR PREPARING
STRIPED SHEET MATERIAL CONTINUOUSLY

ABSTRACT OF THE DISCLOSURE
An apparatus is disclosed for applying at least two abutting stripes of at least two contrasting liquid materials, supplied from liquid sources, onto a web member moving in a predetermined direction with respect to a web-engaging surface of the striping apparatus which comprises at least three puddle rails abutting at right angles to a knife coater. The puddle rails are adjustable to ride on the web member surface to form areas of web surface between adjacent puddle rail and the knife coater in which the liquid material can be deposited in form of stripes as the liquid material passes through the knife coater with the movement of the web material. The concept is particularly adaptable to the production of thermosetting plastic sheet material having integral, substantially parallel abutting colored stripes, the plastic sheet material being preferably reinforced with fiber with the stripes being either opaque or transluscent colors.

Description

~04Z~;15 IM~ROVED APPARATUS FOR PREPARING
STRIPED SHEET MATERIAL CONTINUOUSLY
This invention relates to an apparatus for continuous-ly producing striped sheet material and more particularly pertains to the apparatus for the manufacture of plastic sheet material having substantially parallel abutting stripes of a wide variety of shapes and colors and various combinations o same. The present invention is particularly adaptable to the production of thermosetting plastic sheet material having integral, substantially parallel abutting colored stripes. The thermoset plastic sheet produced by this process can be and preferably is reinforced with fibers and can be either opaque or translucent with either opaque or translucent colored stripes. The strips produced in this invention are always narrower than the width of the plastic sheet material and will contrast in appearance with the next adjacent stripe in at least one respect in regard to color, translucency, or opaqueness, etc. The adjacent stripes m~st be different in color, translucency, etc. from the next adjacent stripe.
The apparatus of this invention relating to the pro-duction of stripes in plastic sheet material is an improvement over the apparatus described in our U.S. Patent No. 3, 716, 431.
According to the present invention, striped sheets or plates comprising a polymeric resin are produced continusously by a process wherein a curable synthetic resin which may be in the form of a liquid or paste containing one or more polymerizable or curable monomeric compounds is passed between moving surfaces which are substantially parallel in the direction of the movement and have subgtantially no relative motion, and the monomeric constituents of said liquid or paste are polymerized between said surfaceg by the action of heat, light, or other type of radiant energy, with or without the application of pressure.
The continuou~ production of sheet material, and

-2-q~

1~)4Z~15 particularly plastic sheet material, if ~urther described in U.S.
2,784,763, for instance. In this prior art process a composite sheet material is produced by moving lo~gitudinally a lower surface film or web, depositing on this web a heat settable liquid resin~, placing in the liquid resin stranded reinforcing material, dis-placing the air in the reinforcing material with liquid resin, then covering the mixture of liquid resin and reinforcing material with an upper film or web, applying pressure to the upper web and lower web to consolidate the mixture of liquid resin and rein-forcing material and thus forming a composite sheet, moving thecomposite sheet longitudinally through a heating zone causing the resin to set and during the movement through said heating zone engaging the opposite surfaces of the composite sheet and shaping it into a desired form in a longitudinal direction.
U.S. Patent No. 2,927,623 describes an apparatus for continuously producing a composite sheet of reinforced plastic material. The apparatus of this patent operates by feeding through the machine a carrier surface vheet of cellulose film such as cellophane onto which a measured quantity of settable resin in liquid form is deposited and spread evenly with a doctor blade. The edge portions of the sheet are raised so as to confine the resin to the central portion of the sheet. Chopped strands of fibrous material are fed onto the resin and simultaneously compacted and pressed into the resin by a plurality of threads extending lengthwise of the sheet. As the loose fiber is held compacted by such threads, a cover surface sheet is laid on the resin and fiber mi~ture, the opposite edges of the surface film are glued together to form a flat tube containing the resin and fiber mixture, and such composite sheet it passed between rolls to squeeze out the air and establish the thickness of the sheet. The ~heet thus formed is then passed through slots of fixed width during setting of the resin, which pre~erably is expedited by passing the

-3-1~42~15 sheets through an oven. After resin has set, the longitudinal edges of the continuous sheet may be trimmed, and the sheet which is composed of chopped strands of fibrous material such as glass fiber embedded in a matrix of cured synthetic resin cut into desired lengths.
U.S. Patent No. 3,077,000 describes an improvement for preparing longitudinally contoured sheet material described in U.S. Patent No. 2,784,763, comprising an apparatus for providing transversely contoured, continuously formed sheet material.
Lines, stripes and different designs have been placed upon sheet objects by stencils, printing and various other means.
There are some materials upon which printing is unsatisfactory and stencils are not adaptable. Patterns can be painted or other-wise coated onto the surface of a panel after the panel is produc-ed but such a process is an expensive additional operation and usually produces a pattern which can easily be worn or chipped off the panel. Panels can also be made with an inserted paper or other inserted sheet material on which there is a printed pattern.
The inserted sheet material is expensive, the process for inserting it is expensive, and lack of complete soaking and integration into the plastic ~nel permits water absorption and blooming.
It is desirable to provide means whereby abutting colored stripes may readily be placed upon continuously formed sheets of reinforced plastic material by flowing paint, lacquer or the like through abutting restricted openings onto one or both of the upper and lower webs and partially curing the abutting stripe or stripes thus formed before addition of the curable resin and fibers to the sheet forming apparatus.
The primary object of this inven~ion is the provision of a striping apparatus in which the size, number, color and arrangement of the stripes may be adjusted readily and closely abutting parallel stripes can readily be produced. Another 1~)4;~15 object isto provide an easily assembled striping apparatus which is of a simple and economical construction.
Thus, in accordance with the present teachings, an improvement is provided in an apparatus for continuously producing a plastic sheet of predetermined cross-section, which comprises means for providing a moving flexible carrier web, means for depositing liquid resin on the carrier web, means for de-positing fibrous-reinforcing material onto the liquid resin and lowering the reinforcing material into the liquid resin, means for placing a flexible cover web on the liquid resin and reinforcing material, forming means of predetermined cross-section, means to pull the flexible webs with the partially cured resin therebetween through the forming means and curing means disposed adjacent to the forming means to substantially completely cure the resin while it is been moved through the curing means. The improvement in such apparatus comprises the inclusion of at least three adjacent puddle rails removably and slidably disposed to ride on the moving carrier web the forward end of said puddle rails abutting a knife coater located just above the carrier web with means for continuously supplying contrasting liquid striping materials between the puddle rails onto the surface of the carrier web.
Our apparatus produces a multiple striped pattern created by a dyed or pigmented resin system, which pattern is chemically bonded with the panel resin and is integral within the panel. This pattern cannot be chipped off the panel, nor will it flake off because it is an integral part of the panel.
Internal blooming or separation of the pattern cannot occur.
The first step in the striping process is that of depositing, by means of our striping apparatus more completely .~
r~ - 5 -~6)42~;15 described herein, at least two coatings of contrasting color or - opaqueness having a definite controlled thickness and specific controlled width onto the carrier sheet and/or the cover sheet such that they form abutting, contrasting stripes longitudinally with the direction of formation of the panel. A plurality of such abutting stripes can be used to form a variety of geometric patterns in the finished panel. Special forms of our striping apparatus deposit the initial coating on the carrier sheet. These stripers are assembled to incorporate side-retention knife means as well as forward metering or doctoring means for the production of each stripe.
The striping apparatus of this invention is provided for applying at least two abutting stripes of at least two contrasting liquid materials, supplied from liquid sources, onto a web member having relative movement in a predetermined direction with respect to a web-engaging surface of the striping apparatus comprising at least three puddle rails abutting at right angles to a knife coater, the puddle rails being adjusted to ride on the web member surface to form areas of web surface between adjacent puddle rails and the knife coater in which the liquid materials can be deposited to form stripes as the liquid material passes through the knife coater with the movement oi the web material, ' ' '' _ , , . .

- 5a -~ d~)42615 preferably the outboard p le rails being angled outwardly at their downstream ends with respect to the direction of relative movement of the web and applicator to prevent or minimize trans-verse leakage of the liquid material.
The thickness of the stripes applied in this manner depends primarily upon the setting of the knife coater or doctor-ing blade in relation to the surface of the web, viscosity of the liquid stripe material, and the speed of movement of the web.
An illustrative doctor blade setting is one that would provide a gap of between 0.001-0.100 inch, through whi~h the liquid stripe material flows.
The puddle rails and doctor blade combination device may be maunted in a~y suitable manner and the distance between adjacent puddle rails can be varied and any number of puddle rails may be used in a given operation.
The general characteristics of the apparatus and process of the present invention will be further illustrated in the accompanying drawings wherein:
Figure 1 is a side elevation view partly in section of the apparatus of this invention.
Figure 2 is a top perspective view partly in section of the forward part of the apparatus of this invention.
Figure 3 is a partial to~ plan view partly in aection of the strrping apparatus of this inve~fion.
Figure 4 is a sectional view taken on line 4-4 of Figure 3.
Figure 5 is a sectional view taken on line 5-5 of Figure 3.
Figure 6 is a sectional view taken on line 6-6 of Figure 3.
Figure 7 is a sectional view taken on line 7-7 of Pigure 3.

~;34~G15 Figure 8 is a sectional view taken on line 8-8 in Figure 1.
Figure ~ is a sectional view taken on line 9-9 in Figure 1.
Figure 10 is an end elevation view partly in section of one striper of the apparatus.
Figure 11 is a side elevation view partly in section of the strpper of Figure 10.
Figure 1 is a cross-sectional over-all view of the striping and panel-forming apparatus including the lower carrier sheet 1 which is unrolled from roll 2 and travels in a plane along table 3. The carrier sheet 1 may be paper or a plastic of a character which may be stripped from the finished composite sheet and conveniently may be a cellulose film such as Cellophane~.
If the surface carrier sheet material is shrunk by heat as celloph-ane is it can be passed through a heating zone before material is placed on it. In this zone heat may be supplied by lamps 4 of the infrared type. On the forward moving lower carrier sheet 1 abutting stripes of colored liquid curable material are contin-uously deposited from between at least three pud~dle rails 5. Thecolored liquid stripes are preferably composed of contrasting dye-or pigment-containing heat curable liquids or pastes of controlled viscosity which are continuously fed between the puddle rails 5 from one or more reservoirs 6 through a conduit 7. A typical liquid stripe material is made up of 70 parts by weight of neopentyl glycol-orthophthalic-maleic polyester compounded with styrene, butyl methacrylate and ultraviolet absorber, 30 parts by weight of propylene glycol-orthophthalic-maleic polyester compounded with styrene and ultraviolet absorber and modified to ; 30 reduce sensitivity to air inhibition on curing, 8 parts by weight of a plasticizer, 1 part of silica aerogel, 1 part silicone resin, 4-9 parts pigment, 0.4 part t-butyl perbenzoate and 0.3 1~4;~615 part methyl ethyl ketone peroxide. The colored stripes are then at least partially cured with a heat curing means such as an infrared heater 8 so that it becomes insoluble and no longer will flow. It is necessary in this step to gel the stripe material enough so that it will not intermix and flow when it contacts the basic panel resin or into the adjacent abutting stripe material and preferably the stripe material is not completely cured until it is co-cured with the basic panel resin. Next there is deposited on the forwardly moving carrier 1 from a spreading means such as a trough 9 a measured quantity of polymerizable resin such as a liquid unsaturated polyester composition. A
typical liquid polyester is composed of 100 parts by weight of propylene glycol-orthophthalic-maleic polyester, compounded with styrene and methyl methacrylate monomers and an ultraviolet absorber, 10 parts of hydrated aluminu~ oxide, 0.75 part of titanium dioxide, O.9 part of benzoyl peroxide and 0.3 part of cumen hydroperoxide. The fibrous reinforcing component of the plastic sheet can be a continuous web of fibers 10 such as that prepared by continuously chopping glass fibers and randomly depositing them on an endless belt in a plenum chamber 11 as is well known in the art. The fiber mat 10 is drawn by the belt 12 and is usually in the form of a loose stack which is distributed uniformly acDoss the width of the belt and distributed onto the layer of resin and abutting stripes being carried by the lower sheet 1. If desired, tensioning threads 13 as more fully described in U.S. Patent No. 2,927,623 may be used and are drawn by roller 14 over the upper side of the pile of fibers carried by sheet 1 to press the fibers down intothe liquid polyester to a uniform thickness. A cover sheet or web 15 which is preferably of the same material as carrier sheet 1 is dispensed from a roll 16 between pinch roll~ 17 and 17~ and can be preheated by heating means such as an infrared lamp 18. Stripes may be deposited on 1~42615 the cover sheet 15 by employing the apparatus and procedure just described for doing this on the carrier sheet 1. Thus, stripes can be deposited on either carrier sheet 1, cover sheet 15, or both; and when stripes are produced on both, they may be arranged in or out of register in the final cured sheet material. The surface of the web 15 becomes the under surface of the cover sheet as it passes between pinch rolls 17 and 17!. Means are used to squeeze the air from the composite sheet structure thus formed as is more fully described in U.S. Patent No. 2,927,623. The composite sheet, composed of a flattened tube of the two edge-sealed surface sheets containing the fibers, resin and threads, passes through a forming oven 19 where it is formed and cured.
During its passage through the oven the sheet may be formed into a c~oss-sectional shape of any desired shape. This operation can be carried out by passing the sheet between ~o~m~g members or dies as is more fully described in U.S. Patent No. 2,927,623. When the finished composite sheet emerges from the oven it may be cut ~
the desired width by edge trim saws 20 and to the desired length by a traveling saw 21 after which the several sheet sections 22 are conveyed to a stacking area. If desired, means also may be provided after oven 19 for stripping the carrier and cover sheets from the finished composite sheet said sheet having the glass fibers disposed beneath the surface of the cured synthetic resin matrix.
Forward movement of the sheet material through the apparatus of Figure ls is effected slowly and uniformly by cooperating endless track~, endless tread belts, draw rolls or other pulling means well known to those skilled in the art and more fully described in U.S. Patent No. 2,784,763. The pulling means is preferably located between the saws 20 and 21.
Pigure 2 is a top perspective view showing somewhat diagrammatically the apparatus for initially forming the stripes and forming the composite sheet, parts being broken away. The lV4;~1S
puddle rails 5 float on the lower carrier sheet 1 as the carrier -sheet passes over the smooth, flat table surface 3. The flow of liquid striping material from the reservoir 6 to the area on the carrier web 1 between puddle rails 5 can be controlled by a metering valve means 24. The wide stripe 23 and narrower stripe 23' are deposited on the lower carrier sheet 1 and are not yet cured by heat but are su~ficiently viscous to hold their shape.
The puddle rails 5 are restrained from forward longitudinal movement by a suitable doctor blade 25 which is secured at each of its ends to the sides of the table 3 by means of a bracket 26.
In Figure 3, which is a top sectional view taken above three puddle rails, the stripes 23 and 23' appear and puddle rail 5' is preferably held at a slight angle against the doctor blade 25.
The stripe process is carried out by depositing a coating of a definite controlled thickness and specific controlled width onto the lower carrier sheet or upper cover sheet, or both, so that at least two longitudinal abutting stripes are continuous-ly formed on the sheet. ~he plurality of stripes can be used to form any variety of parallel geometric patterns in the sheet.
Figure 6 shows stripes 23 and 23' as they are produced just downstream of the doctor blade.
Figure 7 shows stripes 23 and 23' which have flowed together just prior to being partially cured.
Figure 8 shows stripes 23 and 23' which have been partially cured and sandwiched between carrier web 1 and contin-uous web of fibers 10.
Figùre 9 ~hows the completed panel structure just before final curing. The panel structure includes the lower carrier web 1, the stripes 23 and 23', the resin impregnated continuous web o~ fibers 10 and the upper carrier web 15.
Figure 10 shows a rod 27 with slidable clamping 16)4;Z615 devices 28 on which are secured the puddle rails 5.
Figure 11 shows a side view of the same part of the apparatus as is shown in Figure 10.
The invention includes the production of striped, fiber-reinforced polyester structures wherein a mixture, consist-ing essentially of tl~ at least one organic linear polymeric ester containing recurring ethylenic unsaturation, t2) at least one addition-polymerizable ethylenically unsaturated organic monomer, and (3) reinforcing fibers, is subjected to additional polymerization conditions e~fective to produce a striped, cured, fiber-reinforced polyester structure.
Unsaturated polymeric esters suitable for use in the invention for both the sheet forming resin and the strip material include those prepared by condensing under p~lymerizing conditions either ~1~ an ethylenically unsaturated dicarboxylic acid with a diol containing no ethlylenic unsaturation or t2~ a dicarboxylic acid containing no ethylenic unsaturation with an ethylenically unsaturated diol, or most commonly, ~3~ a mixture of ethylenically unsaturated dicarboxylic acids and dicarboxylic acids containing no ethylenic unsaturation with a diol containing no ethylenic unsaturation. Stable diacylchlorides, diesters or anhydrides of the dicarboxylic acids which are available can be and are often substituted in whole or in part ~or the acid.
Among the ethylenically unsaturated dicarboxylic acids and derivaties thereof which are commonly employed can be mentioned fumaric acid, maleic acid and its anhydride, citraconic acid, me~aconic acid, itaconic acid and endomethylene tetrahydrophthalic acid. Among ~he dicarbo~ylic acids and derivatives thereof containing no ethylenic unsaturation which are commonly employed can be mentioned phthalic acid and its anhydride, adipic acid, sebacic acid, ispphthalic acid, ter~phth~lia acidj malonic-acid and glutaric acid~
A frequently employed ethylenically unsaturated diol 1~)4Z615 is 2-butene-1, 4-diol, while among the commonly employed diols containing no ethylenic unsaturation can be mentioned ethylene glycol, propylene glycol, diethylene glycol and dipropylene ~lycol. As will be obvious to thoee skilled in the art, varying the proportions and nature of the ethylenically saturated and unsaturated reactants in these condensations affects the number of carbon-to-ca~bon double bonds in a given polymer chain length available for cross-linking by addition polymerization means.
Among ~he addition polymerizable compounds most commonly employed as cross-linking agents in combination with the above-described polyesters can be mentioned styrene, diallyl phthalate, methyl methacrylate and triallyl cyanurate. Other ethylenically unsaturated cross-linking agents more or less fre-quently employed in these operations include alpha-methyl styrene, divinyl benzene, vinyl toluene, allyl diglycolate, methyl acrylate, ethyl acrylate, ethyl methacrylate, vinyl acetate, acrylonitrile, diallyl maleate, vinyl phenol and allyl carbamate. Frequently re than one of the above cross-linking agents is employed in the same mixture, depending on the properties desired in the final structure and its ultimate use. In general their physical charact-eristics are such that these resins produce a broad, transparent or translucent product by polymerization, but in order to provide toughness and strength, fibrous reinforcing material is preferably embedded in such resins. In a sheet four feet wide, eight feet long and one-sixteenth of an inch thick, for ins~ance, thrrty - percent by weight of the sheet can be reinforcing material and seventy percent resin, although the proportions of resin and fiber can be varied considerably.
A polymerization catalyst may be incorporated into the unsaturated polymeric ester of this invention. Suitable polymer-ization catalysts are peroxides such as benzoyl peroxide, acetyl peroxide, t-butyl peroxide, di-t-butyl peroxide, methyl ethyl ~.6)4'~615 ketone peroxide, lauryl peroxide, cumene hydroperoxide, cyclo-hexane peroxide and the like: azo compounds such as azobisisobut-yronitrile and the like. Accelerators or promoters such as cobalt naphthenate, phenyl phosphinic acid, p-toluene sulfonic acid, and some tertiary amines such as dimethyl sniline, are also frequently employed. The polymerization or curing reaction of the monomeric compound can also be initiated by radiant energy such as light, X-rays, or nuclear radiation which may or may not be used in con~unction with chemical initiators and activators which are all well known to those skilled in the art.
~ he resin preferred for use in the manufacture of sheet material produced by the present process is one of low viscosity which will readily impregnate the reinforcing material and on exposure to heat will set into a hard, dense, infusible state.
For transparency a clear, light-stable resin is desirable. For decorative purposes a light colored resin which may be tinted by the addition of pigments or dyes is desirable. For clarity a resin which has an index of refraction closely matching that of the reinforcing material is desirable. All these characteristics may be found in a family of resins-called "p~lyesters" which are well known to be settable by the process of polymerization.
Reinforcing fiber is preferably additionally incorpor-ated into the unsaturated polyester mixture. Any suitable rein-forcing fiber may be employed, such as, for example, asbestos, nylon, cellulosic and the like mineral and organic fibers. Glass reinforcing fibers are preferred, particularly from the strength-versus-cost standpoint. Fibrous glass is availa~le for reinforcing structures in the form of cloth, yarns, mats, rovings, milled fiber~, parallel strands, surfacing mats and loose fibers. The ~election of the particular form in ~hich the glass fibers are to be used and the qua~tity thereof in proportion to the other ingredients in the mixture permits wide latitude and is a further means of varying the properties of the final structure, in addition to varying the proportions and ~pecific nature of the polyester and cross-linking agents, respec~ively.
Glass mat is composed of a number of layers of glass fiber bundles, crossing at random and banded loosely together with resin. Glass cloth or other woven fibers may also be used ; in the apparatus to manufacture reinforced resin sheet.
Fillers such as pigments, clays, mica, silica, talc, etc., can be incorporated into the unsaturated polyester-fiber mixture prior to curing.
The material used for the surface elements or upper and lower carrier webs should be thin, nonporous, inexpensive and sufficiently strong to carry the resin and reinforcing fiber material entirely through the sheet forming apparatu~ without being ruptured. It has been found that cellulose film, that is Celloph-ane ,meets these requirements, although it is entirely feasible to u~e other materials such as cellulose acetate film, polyvinyl .
chloride film, vinyl chloride/vinyl acetate copolymer film and polyethylene film for instance, which like Cellophane will part from the resin sheet, or polyester film and polyvinyl fluoridefilm more f~lly described in U.S. Patents Nos. 3,284,277 and 3,257,266 which will adhere to the resin and become an integral part of the finished sheet imparting weather stability and other desirable properties to the sheet. Endless belts of a material such as stainless ste~l can be used for surface elements in the process of the present invention.
Stripping or release agents, ~or instance surface active agents, may be applied to the carrier webs or incorporated into the monomeric compounds to facilitate the separation of the polymerized, finished composite sheet from the moving surfaces.
It will be apparent that the motion of the moving ~urfaces, while remaining substantially parallel, may, with 104;~15 advantage, be so arranged that the surfaces~are brought slightly closer together in passing through the region in which polymer-ization is taking place. In this way it is possible fo follow up the shrinkage of the polymerizing mass, that is the sheet.
During its passage through the oven the sheet may be formed into any desired cross-sectional shape. This forming operation is accomplished by passing ~he sheet between forming members or dies of complemental contour. Pairs of these members may be located a few feet apart and the width of the members ia the direction of travel of the sheet may be of the order of one inch. The lower member are fixedly mounted and the upper member of each pair can be raised and lowered by suitable mechanism.
The novel striped sheet material embodied herein is useful in a wide variety of ways, particularly as a material-in the construction of walls, room dividers, doors, sky lights, privacy fences, patio covers, windows, and the like.
It is to be understood, however, that while the invention as herein described is concerned with a continuous length of sheet material that various modifications might be made ~ven to the extent of treating individual pieces of material by the method and essential means shown without departing from the point of the invention.
It is todbe understood, also, that while we have herein shown and described particular embodiments of our invention that changes in form and construction may be made within the scope of the appended claims.

Claims (3)

The embodiments of the invention in which an exclus-ive property or privilege is claimed are defined as follows:

1. In an apparatus for continuously producing a plastic sheet of predetermined cross-section, which comprises means for providing a moving flexible carrier web, means for depositing liquid resin on the carrier web, means for depositing fibrous-reinforcing material onto the liquid resin and lowering the reinforcing material into the liquid resin, means for placing a flexible cover web on the liquid resin and reinforcing material, forming means of predetermined cross section, means to pull the flexible webs with the partially cured resin therebetween through the forming means and curing means disposed adjacent to the forming means to substantially completely cure the resin while it is being moved through said curing means, the improvement comprising the inclusion in the apparatus of at least three adjacent puddle rails removably and slidably disposed to ride on the moving carrier web the forward end of said puddle rails abutting a knife coater located just above said carrier web and means for continuously supplying contrasting liquid striping materials between said puddle rails onto the surface of said carrier web.

2. The apparatus of claim 1 wherein the means for lowering the reinforcing material into the liquid comprises continuously supplied parallel filaments under tension which are applied to said reinforcing material.

3. The apparatus of claim 2 wherein there is also included a second curing means between the knife coater and the means for depositing the liquid resin on the carrier web.