US 3833703 A
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5Pt- 3, 1974 PQE. .loosl STRUCTURED SYNTHETIC WEB MATERIAL AND METHOD FOR THE PRODUCTION THEREOF 4 Sheets-Sheet l Filed Harsh 17, 19272 lvl'.
Sept. 3, 1974 P, E. Joos A :$833,703
STRUCTURED SYNTHETIC WEB MATERIAL AND METHOD FOR THE PRODUCTION THEREOF Filed Harsh 17, 1972 v 4 Sheets-Sheet 2 FIG. 2
Sept. 3, 1974 3,833,703
P. E. JOO STRUCTURED SYNTHETIC WEB MATERIAL AND METHOD v FOR THE PRODUCTION THEREOF' Filed larch 17, 1972 4 Sheets-Sheet 3 FIG. 3
Sm. 3. 1974 P. E. Joos. 3,833,103
STRUCTURE!) TH C WEB MATERIALOND METHOD F0 HE ODUGTION THERE Filed latch 17. 1972 4 Sheets-Sheet 4 United States Patent O 3,833,703 STRUCTURED SYNTHETIC WEB MATERIAL AND METHOD FOR THE PRODUCTION THEREOF Pierre Emmanuel Joos, Gleize par Villefranche-sur-Saone, .France, assigner to Continental Linoleum-Union Betriebs AG, Zurich, Switzerland Filed Mar. 17, 1972, Ser. No. 235,669 Claims priority, application France, Mar. 2.2, 1971,
y 7109967 Int. Cl. D01d 5/20 U-.S. Cl. 264-167 7 Claims lABSTRACT oF THE DISCLOSURE A flexible synthetic surface structured web material embodying a discontinuous upper layer formed of crosslinked plastic with a Youngs bending modulus of elasticity in a range of 10,000 to 30,000 kg./cm.2 and a continuous lower layer or stratum formed of cross-linked plastic with a'Youngs bending modulus of elasticity in a range of 3,000 to 10,000 kg./cm.2, both layers being bonded to one another by common or joint polymerization.
The method for the production of such flexible synthetic surface structured web materials comprises applying to a molding band possessing recesses a first mass containing a hardenable polyester mixture, possessing a Youngs bending modulus of elasticity following polymerization which is in a range of 10,000 to 30,000 kg./cm.2. There is applied such quantity of this mass to the molding band that only the recesses thereof are filled, and thereafter such mass is gelled. A second mass is applied to the gelled cooled massv discussed above, this second mass containing a hardenable polyester mixture possessing a Youngs bending modulus of elasticity following polymerization which is in a range of 3,000 to 10,000 kg./ cm?, the second mass is then levelled into a layer and the entire'structure or arrangement is then hardened at elevated temperatures and removed from the molding band so that there is obtained a dual-layer structured web material.
BACKGROUND OF THE INVENTION The present invention relates to improvements in synthetic materials intended to be used as the linings or coverings for walls or the like of structures. In particular, this invention is vconcerned with a surface structured web material, that is to say, aweb material or web exhibiting protruding plastic ornamentation and having sufficient flexibility in order to be wound into roll-shaped configuration, yet owing to its particular properties does not tend to curl or roll-.up upon itself and consists of a cross-linked plastic. Apart from the above the invention is also concerneid with a new 'and improved method for the fabrication of the different embodiments of inventive web material.
Now for the purpose of lining or covering the walls of structures, typically building structures, there are employed either ceramic tiles, for instance in swimming or bathing establishments, bathrooms, toilets, and so forth; tapestry or wallpaper for living areas, offices and so forth, or'linings orvcoverings which can be applied by means of rolls or spray guns, such as rough plaster, coats of oil paint and coatings formed on the basis of a plastic dispersin as the basic material or binders. All of these coverings `or linings require a smooth or level substrate, that isto say, a Vlevelling layer (smoothing coating) must be applied to thera'w structure and Awhich compensates for irregularitieslifints, holes and so forth present at the raw building structure. This workl is extremely cumbersome, application of the aforementioned coverings or linings reqiring'a great deal' of time and is expensive since the work inst be manually performed, especially tiling.
3,833,703 Patented Sept. 3, 1974 vCC Accordingly, attempts have already been made to find possibilities which overcome these drawbacks. Hence there has been proposed in this particular art the use of thermoplastic materials which, however, again have been found to possess other drawbacks. They have a high thermal coefficient of expansion, leading to peeling away or detachment from the wall and to warping, they tend to tear and age, so that unsightly fine fissures appear which can no longer be gotten rid of, oftentimes they are associated with an unpleasant smell, and owing to evaporation tend to lose their plasticizer which can result in pronounced allergies for the inhabitants of the associated area or living space.
It is for these reasons that proposals have also already been advanced in this particular art to employ plates formed of materials which are not thermoplastic, namely especially those formed of duroplasts or thermosetting materials, for instance urea formaldehyde resins, melamine resins, phenolic resins, and so forth. Yet this type of material is rigid and tends to fracture. Also polyester, even if reinforced with glass fibers, possesses these drawbacks. In particular, the fabrication, storage and mounting of rigid plates formed of such materials is expensive, re-
quires a great deal of space, and is cumbersome, and
hardly affords any advantages in contrast to ceramic plates or tiles.
OBJECTS OF THE INVENTION With the foregoing background in mind, it is to be understood that a primary objective of the present invention is to provide improved structured synthetic web materials not associated with the aforementioned drawbacks and disadvantages of the prior art proposals.
Another and more specific object of the present invention relates to an improved flexible, structured material which does not exhibit the aforementioned drawbacks and which can be used to considerable advantage in building structures for the lining or covering of walls, and wherein the exibility should be so great that such material possessing 2 millimeters thickness can be wrapped about a mandrel of 1 centimeter diameter without the formation of fissures or cracks.
Still a further object of the present invention is to provide an at least double-layer web material possessing the aforementioned properties, and wherein the first layer, namely the surface or top layer, is discontinuous and affords the desired structured effect, and the second and, if
desired, the further present layers, are continuous andv thermally hardened (thermosetting) plastic, the bendingi elasticity of the individual layers being adjusted such that the top or surface layer possesses a high coefficient of bending elasticity or Youngs modulus of elasticity during bending, hereinafter conveniently referred to as BEK, and wherein the surface is extremely resistant, and the second layer and/ or the lowermost layer possesses a lower BEK, by means of which there is insured for the good bendability or flexibility of the composite material.
It is an additional object of the invention to provide av web material which is equipped at its bottom or lower face with a base layer which is fixedly connected with the web material and has the function of affording a reinforcement, a thermal and/ or acoustical insulation,v provides",
adherence with the supporting or substrate surface and/or compensates for the different expansions of the structure and linings, as such can be caused by the effects of heat and/or moisture.
And a further object of the invention relates to improved techniques for the production of the aforementioned web materials and which enable obtaining this web material in a very simple and economical fashion and bringing about an intimate bonding or uniting of the individual layers with one another. In particular the method of this development is intended to be suitable for continuous operation.
DETAILED DESCRIPTION OF THE INVENTION Now, in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, it is here mentioned that the inventive exible structured web material is generally manifested by the features that it possesses a discontinuous top or surface layer consisting of cross-linked plastic having a bending coefficient of elasticity in the range of 10,000 to 30,000 kg./cm.2 and a continuous lower layer connected therewith by a common or conjoint cross-linking operation, the lower layer consisting of cross-linked plastic having a bending coeiicient of elasticity in a range of 3,000 to 10,000 lig/cm?.
Preferably both of the layers consist of cross-linked polyester, modied in such a manner that it exhibits the required BEK. The manner in which such modification can occur will be explained more fully hereinafter. Instead of using polyester it is possible to also employ a different equivalent material, for instance an appropriately modified epoxy resin.
In the event that the BEK of bo-th layers borders the outermost limit of the previously indicated range, then, for the purpose of compensating for possible stress at both layers it is advantageous to provide an intermediate layer, the BEK of which is at an intermediate value or range, that is, for instance has a value in the order of magnitude of 8,000-l5,000 kg./cm.2, for instance around 11,000 kg./cm.2.
The thickness of the layers is not critical and is primarily dependent upon the requirements concerning manufacture and use. As a lower boundary value there is mentioned 0.1 millimeters, the thickness of the layers can amount up to l millimeter and above, for instance 1.5 or 2 millimeters. Generally, the lower layer possesses the same or a greater thickness than the upper layer, for instance up to twice the thickness of the upper layer. This is possible because the upper layer is very wear resistant.
According to another embodiment of the inventive -product which possesses three plastic layers there is embedded at the lower layer a base layer in such a manner that the free surface of the base layer remains free of the components of the lower layer. There is advantageously employed as the base layer a needled fleece or web formed of endless polyester fibers. A composite or compound material containing such fleece as the base layer cannot be torn; the base layer can be adhesively bonded with the building structure and owing to its elasticity and the numerous air-filled voids or interstices forms an eX- tremely good connection capable of compensating for stresses which occur between the structure and the lining and functioning as a thermal and acoustical insulation. Instead of using fleece it is possible to also employ for the base layer paper, plastic foils, metal foils, cardboard, fabrics, foamed materials formed of polyurethane or PVC, glass fibers and so forth. The free surface can also be provided with an adhesive for instance a bitumen layer or a contact adhesive; in so doing there is generally required a protective coating or covering formed of siliconized paper.
In the description to follow there is mentioned hardenable polyester resins suitable as the material for the inthat also other plastics having equivalent properties can dividual layers. However in this regard it should be stated employed, for instance epoxy resins.
There will now be considered the measures which enable adjusting or regulating the desired BEK. The BEK is measured by means of a Instron-Dynamometer according to the French Standard NF T 50001, which corre sponds to ASTM-Standard D79049T, and specifically such test is undertaken at samples obtained byv cross'- linking a mixture of unsaturated polyester andfa vinyl comonomer, especially styrene in the presence of the usual catalysts and accelerators, and specifically for seven minutes at C.
The desired BEK can be realized by chemical modification of the polyester and adjustment of the quantity andl.-Addition of adipic acid and/orsebacic acid orl another saturated dior polycarboxylic acid to the acidic component;
2.-Partial or complete replacement of the maleicracid by fumarie acid.
Precautions taken with regard tothe comonomer work in the same sense, which can be carried out alone, in combination and/or together with modification of ester:
3.--Limiting the quantity of styrene to a maximum of, 20% by Weight of the mixture of styrene and poly-HV ester; 4.-Addition of phthalic anhydride; 5.--Addition of a second comonomer, `namely methyl methacrylate, in quantities of 15%-20% rbyweight;
and v v 6.-Addition of a third comonomer with plasticizing properties, for instance diallyl phthalate.
It has been found that apart from'the adjustment 0f the BEK the aforementioned measures also bring about additional unexpected advantages, namely the following: The partial or complete replacement of the maleic acid by fumarie acid results in the formation of clear, transparent layers having a crystal-like appearance whchapfproximates that of glazed wall tiles. Polyesterformed of fumarie acid, adipic or sebacic acids and phthaloanhy dride as well as colorless glycols produce the same ad.-` vantageous results. The addition of phthalic anhydride (item 4 above) produces particularly homogeneous products because the solubility of the comonomer of lcomonoI mers in the unsaturated polyester is increased. The viscos- 7. ity of the masses and the resistance of the finished product against yellowing is improved y by the addition, ofA
0f course the individual layersy can contain d'yes,l.eX-if` tenders, pigments, fillers and so forth. These materials are known in large numbers to the `art so that detailing same is believed to be unnecessary. Still reference` is made. to the publication by Saechtling-Zebrowski, Plastic Hand- E book, pubiishd by carl Hanser-publishers ef Munich; Germany. Generally speaking, it is possible to employ, inorganic and organic dyes, white pigments such as Ti02, v silicic acid, Al203, zirconium dioxide, dulling or deluster-l ing agents such as Cab-O-Sil, fibrous and,nonfbrousf.,l fillers and also, if desired, reinforcement materials.A EX- amples of well known dyes suitable for yuse. ,with the,d invention are set forth -in Ullmanns Encyclopedia` of ,l Technical Chemistry, 3rd edition, 1960, volume I I,' at page 8l et. seq. It should of course be self-eyidentffthat the selection of lthese various additives isto bender. taken in a manner that the desired properties .of .the inventive web material are not disadvantageously affected..v vf.
the poly# 5. Individual additives will be further 'considered in conjunction with the illustrative examples to follow.
The inventive method for the continuous fabrication of the new and improved web material is based upon the common or joint polymerization of all of the layers and not upon the lamination of webs or their adhesive bonding, welding and so forth. It is based upon the features that a rst hardenable polyester resin mass is cast or poured upon a molding band provided with depressions or hollow cavities, casting being undertaken until the depressions of the molding band are filled. Thereafter the cast material is heated until gelling and then cooled. Now there is cast or poured a second hardenable polyester resin mass until there is obtained a continuous layer, the entirey unit or structure then being polymerized by heating and the thus obtained web material is stripped from the mold, that is, raised off of the molding band. The proportion of polyester in the resin masses is selected such that the first layer, after polymerization, possesses a BEK f 10,000 to 30,000 kg./cm.2 and the second, continuous layer, which forms the lower layer, possesses a BEK of 3,000 to 10,000 kg./cm.2. A three-layer web material, that is to say, such web material having an intermediate layer which improves the properties thereof, can be obtained in analogous fashion in that the procedures explained above are carried out and after gelling the second layer (intermediate layer) there is applied the third Vlayer (bottom layer), such is gelled and the entire structure or unit is then polymerized. In this case the starting materials for the second layer are selected such that after polymerization this second layer possesses a BEK which is located intermediate that of both other layers.
In the event that it is desired to apply a base layer of a foam-like or fiber-containing material then there is pressed onto the not yet gelled lower or bottom layer a web of such material in such a manner that the polyester mass penetrates into the surface regions of this base layer web, yet does not completely penetrate therethrough. After joint polymerization the base layer is then iixedly anchored with the composite material.
There will now be given hereinafter certain examples which will'be discussed in conjunction with the drawings for the purpose of even further elucidating the concepts of .this development.
BRIEF DESCRIPTION OF THE DRAWINGS l The invention will be explained and illustrated in greater detail with reference to the accompanying drawings and examples which illustrate preferred embodiments, but are not intended to limit the invention in any way. More precisely, it will be recognized that:
FIG. 1 schematically illustrates equipment for carrying out the inventive method and the various procedural steps involved therein;
FIG. 2 schematically illustrates a wall lining or covering having a tile structure of square or quadrangular configuration;
FIG. 3 schemactially illustrates a wall lining or covering having a tile structure and produced according to the invention and exhibiting a shscale-like or. imbricated configuration;
FIG. 4 schematically. illustrates a Wall lining or covering having a tapestry or wall paper-like structure; and
FIG. 5 is a sectional view through a material with a ber fleece-base layer.
FURTHER DESCRIPTION OF THE INVENTION IN CONJUNCTION WITH EXAMPLES'AND ABOVE DRAWINGS l m The invention will now .be explained inlgreater detail in conjunction with anumber of examples and while making reference to the above drawingslt is to be understood that thejexamples are given by way of illustration and not limitation. Further, unless specifically stated and the percentages percent by weight of the relevant materials.
EXAMPLE 1 (FIGS. 1 and 2) A. Now upon a supply roll 1 there is located a jute fabric 2, possessing a width of about 2 meters, a strength of approximately 320 g./m.2, a strength in the warp direction of about 118 kg./5 cm. and in the weft direction of about 88 kg./5 cm. The rear face of the jute fabric 2 is provided with a reinforcement mass formed of polyvinylchloride in which there are suspended cork particles. At the surface thereof there is initially applied a thin plastisol-adhering layer which is polymerized. Upon this adhering layer there is then poured a plastisol-molding layer 3, in a quantity of about 500 to 800 g./m.2, from a casting or pouring device 4 and such is then levelled or smoothed by means of a doctor blade or squeegee 5. The continuously moving band together with the molding layer 3 is polymerized by means of heating device 6, and most advantageously in a tunnel, so that a the molding layer 3 is still plastic.
Now with the aid of the molding roller 7 which is equipped with the recesses 8 there is continuously impressed a pattern at the plastic molding layer 3, this pattern forming the negative of the web material to be produced. A counter roller 9 takes up the pressure exerted by the molding roller or roll 7. The thus produced mold i.e. molding band 10 is hardened in a tunnell 11 at 180 C. so that there is formed a continuous, hard, yet flexible mold.
Instead of employing a molding band which can be fabricated in accordance with the described technique, it would also be possible to resort to the use of an already prepared molding band, for instance formed of metal and which continuously revolves, as will be explained more fully hereinafter.
B. The inventive method begins at the location of the equipment depicted in FIG. l represented yby the chain or phantom line 12.
Now upon the molding band 10 obtained according to the procedure A discussed above there is poured or castfrom a pouring or molding device 13 a mass containing:
Ga l part tertiary-butyl-per-Z-ethylhexoate.
This mass is then levelled or smoothed by means of the doctor blade or squeegee 14 in such a manner that only the recesses or depressions 15 of the band 10 are dilled out. With a smaller height of the webs 16 of thisv band there is obtained a surface weight of the first discontinuous layer which is in a range of 200-600 g./m.2 (web height amounting to approximately 0.2-0.6 millimeters).
Now at the heating tunnel 17 this layer is gelled for three minutes at C. to 100 C. and then cooled.
Now upon the gelled layer 18 there is poured from the casting or molding device 19 a mass composed of parts polyester resin 2 unsaturated, as above, however having a BEK of approximately 8,000 kg./cm.2, obtained by reducing the styrene content and adding an additive of diallyl phthalate to the resin 1;
0.1 parts cobalt naphthenate;
10 parts TiOz-pigment (rutile);
1 part tertiary butyl-per-Z-ethylheXOate.
This mass is then levelled or smoothed by means of the doctor blade in such a manner that there is obtained a surface weight of the layer 21 of approximately 500 g./m.2 (thickness of approximately 0.5 millimeters).
Now at the tunnel 22 the entire unit or structure is polymerized at 120 C. for nine to ten minutes. Thereafter the iinished web material 23 is lifted off the molding band 10, while such molding band 1 0 is rolled up about the winding or coiling roll 24.
As shown in phantom lines in FIG. 1 is would be also possible to use an endless molding band 10a which in such case would be delivered in the direction of arrow 25 to a schematically represented deiiecting roller or roll 26 and would move continuously over the rollers 24. and 26.
According to the above example there are produced approximately 2,000 m? of web material per day.
The employed polyester resins possess the following properties:
1 SPI designates the Method of the Society of the Plastics Industry, New York (U.S.A.). The employed testing technique iS as follows: 50 grams resin mixture are admixed with 1 grani of a 50% benzoyl peroxide paste. After one hour 25 grams of the mixture are poured into a test tube or reagent glass (length 150 millimeters, diameter 19 millimeters). The temperature is measured at the center of the test sample with a. resistance thermometer and recorded. The filled test tube is immediately introduced into a liquid bath at 82.2 C.i0.1 C. (boiling point of isopropanol). The gelling time is the time required between 65.6 C. and 87.8 C. of the sample temperature. The hardening time is the time between 65.6 C, and the maximum temperature arisin at the sample (maximum eXO- thermic reaction temperature.
According to this example there is obtained, for instance a product which possesses the appearance of laid ceramic tiles (FIGS. 2 and 3); the upper layer 1.8 forms glossy, colored, protruding ornamentations with a quadratic (FIG. 2) or iishscale-like (FIG. 3) configuration, whereas the white pigmented lower layer 21 can be seen at the locations of discontinuity of the upper layer 18 and brings about the impression of white produced joints between the tiles.
The obtained web material is ilexible, cuttable and does not distort and roll-up.
EXAMPLE 2 There are carried out the procedures explained above in connection with Example l, wherein the molding band 10 however possesses irregular, elongate recesses or depressions. The upper layer 1.8 is dyed brown and contains gold bronze powder. The lower layer 21 contains a yellow pigment. There is obtained a structured wall lining or covering which can be adhesively bonded to irregular, substrates containing holes, this structured lining serving as tapestry for living areas.
EXAMPLE 3 Three-layered web material The procedures described in Example 1 are carried out up to the point of gelling of the upper layer 18.
By means of the pouring or casting device 19 there is poured onto the molding band 10 a mass of Smoothing or levelling is carried out to a surface` weight of 300 g./m.2 (layer thickness in the range of 0.25 to 0.3 mm.), gelling takes place for three minutes at 82 C. and cooling then occurs (layer 21). p
Upon the gelled layer 21 there is poured a mass of parts resin 2 (Example l);
0.1 parts cobalt naphthenate;
2 parts SiOZ, colloidal;
2 parts TiO2-pigment (rutile);
2 parts alkali-free glass iibers, 3 mm. length methacrylic silane;
20 parts micronised talcum;
1.20 parts ethylene glycol;
1 part catalyst (tertiary butyl-per-Z-ethylhexoate) (layer Smoothing or levelling is carried out until reaching a surface weight of 500 g./m.2 (layer thickness of approxitreated with mately 0.45 mm.) and the entire unitis polymerized for nine to ten minutes at C.
There is obtained a three-layer product having a tile structure of the type shown in FIGS. 2 and 3.
EXAMPLE 4 The procedures carried out in Example 3 are followed,
however there is applied to the non-gelled layer 27, under' a light pressure of about 5-40 ig./cm.2, a `iieece or web formed of continuous polyester fibers in such a manner that the layer 27 does not penetrate through the eece.
There is then proceeded further in the manner ofv Example 3 and there is obtained a fiber-reinforced product which cannot be torn, and which has been shown in cross-section in FIG. 5. Such exhibits exceptionally good bending and strength characteristics. It can be used as a wall lining or covering `for bathrooms and shower areas.
In FIG. 5 the lower layer has been designated by reference character 27 and the fleece by reference char acter 28.
The obtained material is odor-free and does not tend to roll-up and distort. n
EXAMPLE 5 The procedures explained in Example 4 above are carried out, however there is employed instead of the polyester iiber fleece a voluminous exible cardboardhaving a surface weight of g./m.2.
There are followed the procedures of Example 5. The
obtained product is coated at the cardboard side with a neoprene-adhesive material in the form of a solution in hexane, dried and covere'dvwith a protective' layer formed of siliconized paper. 2
While there are shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but-may be otherwise variously embodied and practiced within the scope of the following claims. v
Accordingly, what is claimed is: 5 1. A method for the fabrication of web-like materials of the typehaving aliirst discontinuous layer,
comprising the steps of applying a iirst mass toa molding' wallf'orf tloor covering of exible synthetic surface structured web band possessing depressions to form a first discontinuous layer, said first mass containing a hardenable polyester mixture which after polymerization possesses a Youngs bending modulus of elasticity in the order of magnitude of 10,000-30,000 kg./cm.2, applying such quantity of said mass to the molding band that only the depressions of the molding band are filled with such mass, thereafter gelling such mass and cooling same to such an extent that it is still tacky, applying to the gelled, cooled mass a second mass containing a hardenable polyester resin mixture which after polymerization possesses a Youngs bending modulus of elasticity in the order of magnitude of 3,000-10,000 kg./cm.2, smoothing the second mass into a second layer, and then hardening the entire unit at elevated temperature and removing such from the molding band to thereby obtain a double-layer structured web material.
2. The method as defined in claim 1, further including the steps of applying a third continuous intermediate layer composed of a hardenable polyester mixture to the gelled, cooled discontinuous first layer, smoothing, gelling and cooling the third continuous intermediate layer to such as extent that it is still tacky, further cooling said third layer and then applying the aforementioned second mass and smoothing such into said second layer, then hardening the entire unit at elevated temperature and removing such from the molding band, to thereby obtain a three-layer structured web material containing a first upper layer, a second, spaced layer and a third intermediate layer between said lfirst and second layers, said third intermediate layer comprises a polyester mixture having a Youngs bending modulus of elasticity Which is of an order of magnitude lying between that of the upper layer and lower layer and said third layer.
3. The method as defined in claim 2, further including the step of embedding a member into the layer formed of the second mass prior to polymerization so that it is at most partially penetrated by such mass, to thereby obtain a four-layer web material composed of an upper layer, intermediate layer, lower layer and base layer.
4. The method as defined in claim 3, wherein the material embedded into the second mass is a member selected from the group comprising fiber-containing web material, foamed web material, metal foils and plastic foils.
S. The method as dened in claim 3, further including the step of providing the surface of said base layer with an adhesive.
6. A method of making continuous wall or fioor covering webs having an external surface which is of Sculptured effect simulating tile or the like comprising the steps:
(a) providing a first hardenable polyester mass having a Youngs modulus of elasticity ranging from 10,000 to 30,000 kg./cm.2, after polymerization;
(b) providing a second hardenable polyester mass having a Youngs modulus of elasticity ranging from 3,000 to '10,000 kg./cm.2, after polymerization;
(c) forming a first thin, discontinuous layer of said first hardenable polyester on a molding band having patterned recesses by depositing said first hardenable polyester into recesses provided in said molding band;
(d) gelling said first layer;
(e) forming a second, thin continuous layer of said second hardenable polyester directly on said iirst gelled layer;
(f) simultaneously polymerizing said first and second layers to form a unitary web; and
(g) removing said polymerized layers from said molding band as a finished composite article having irnproved flexibility characteristics such that a two millimeter thickness web can -be wrapped about a mandrel of one centimeter diameter without forming fissures or cracks therein.
7. A method according to claim 6 wherein the thic-kness of said rst and second layers is up to about 2 mm.
References Cited UNITED STATES PATENTS 3,473,989 10/1969 Richmond 156-242 2,602,742 7/ 1952 Buskes et al. 156-242 3,464,875 9/ 1969 Brooks et al. 156-242 3,650,880 3/1972 Tieniber 156-246 3,709,752 1/ 1973 Wistozky et al. 156-242 3,194,856 7/1965 Palmer 156-242 2,688,581 9/1954 Stubbs 156-231 3,515,778 6/1970 Fields et al. 264-167 GEORGE F. LESMES, Primary Examiner W. R. DIXON, IR., Assistant Examiner U.S. Cl. X.R.