MXPA98003384A - Felt in lam - Google Patents

Abstract

The invention relates to a felt sheet material of light weight suitable for use as a roof and underlying board and additional facing insulation which comprises, on a dry basis: (a) 60-80% by weight of cellulose fibers; (b) 15-30% by weight of glass fibers having a diameter of 5 to 16 micrometers and a length of 9.5-19 mm (3 / 8-3 / 4) inches), (c) 4-10% in binder weight and (d) 0.5-10% by weight of non-asphalt sizing agent having a flash point above 65 ° C (150 ° F) and an evaporation rate less than 1, which is selected from the group which consists of anionic colophonic and amphipathic esters and anhydride preparations and mixtures thereof. The felt of this invention is of a considerably lighter and more porous weight compared to other felt materials used for the same purpose and can be supplied in rolls of continuous sheet larger than those hitherto practical from the point of view. view of handling, transport, storage and installation. In addition, the felt in current sheet can be produced in a conventional felt-making equipment, in a process of an

Description

FIELTRO AT ftMPCi AM KC? DENTS OF THE INVEN ICN The invention relates to a felt laminate suitable for use as sizing and as an underlying roof or as a cladding sheet for conventional closed-cell foam insulation boards. Prior products for the same use are typically made of asphalt and cellulose / fiberglass compositions of mixed length containing primary glass fibers having a length of 6.3 mm (1/4 inch) in length and a diameter of 15-20 micrometers However, serious problems have been encountered in the manufacture of such felts, since the asphalt, when added to the composition, makes the equipment gummy and requires frequent suspensions for cleaning. In addition, the low dimensional proportions of the fiber (fiber length divided by fiber widths) of the glass filaments in interior felts has led to agglomeration of glass fibers in objectionable lumps which alters the formation of sheet and decreases the velocities of production. Previously it has been believed that glass fibers suitable for roofing and lining walls require a thickness of more than 15 micrometers for strength and a REF: 27314 length of 6.3 mm (1/4 inch) or less for good porosity. However, it has now been discovered that such fibers are brittle and form glass spheres during dispersion in the felt manufacturing process. Since it is common practice to roll felts produced in a felt mill in roll sizes suitable for handling and shipping, serious considerations regarding the weight of the felt and convenience for the consumer must be provided. Thinner and more manageable rolls of a longer length are desired, which avoids frequent patching and less waste. Unfortunately, these objectives are not obtained without sacrificing other desirable properties such as tear strength, low porosity, and tensile strength. The previous products also suffer from poor dimensional stability, that is, a growth in the product dimension when exposed to moisture conditions due to the absorption of cellulose water. Accordingly, it is an object of this invention to provide a laminated felt of lighter weight suitable for underlayment in ceilings and lining of walls, and veneers for insulation boards which not only retain significant beneficial properties but also obtain greater porosity , greater resistance to tearing and better foam adhesion and at the same time solve the previous disadvantages of equipment failure and formation of glass spheres. Another object of the invention is to provide a significant reduction in costs in the commercial production of laminated felts. These and other objectives and advantages will become apparent from the following description and display.

THE INVENCIQLSG According to this invention, there is provided a non-asphalt laminated felt composition and a product consisting essentially of, on a dry basis, (a) 60-80% by weight of cellulose fibers; (b) 15-30% by weight of glass fibers having a fiber diameter not exceeding 16.5 microns and a fiber length of 9.5-19 mm (3/8 to 3/4 inches); (c) 4-10% by weight of binder for the fibers; and (d) 0.5-10% by weight of non-asphalt sizing agent having a flash point greater than 65 ° C (150 ° F) and an evaporation rate of less than 1, which is selected from the sizing group of anionic rosins and antipathetic preparations, for example, esters of C16 to C30 and anhydride preparations, and mixtures thereof. In a preferred embodiment, the binder is an SBR latex, the cellulose fibers are derived from newspaper and corrugated Kraft waste containing at least 50% fibers of 1.5-3.5 millimeters in length and 0.8-2.5% by weight of agent. of sizing It is also desired that the laminate composition contains glass fibers containing a fiber dimension ratio of between 600 and 1450. The glass filament diameter of the present composition is critical for flexibility and superior tear strength and fiber length It is critical to avoid the formation of glass spheres during the manufacture of the felt. In the conventional glass filaments listed in the following table I, only those having a diameter between 5 and 16.5 micrometers, ie, D-M filaments, are suitable for this invention. Although the M fiber can be used, its larger thickness tends to increase the brittle condition and is therefore ruptured during severe mixing conditions. Consequently, for the M fiber, moderate and shorter mixing periods are recommended in order to prevent the lower dimensional proportions of the fibers from breaking. Filaments below Class D are much more expensive to produce and do not have the sphere strength for fiber, for use in current felts. Consequently, diameter fibers of the G-K classes are preferred.

TABLE I DIAMETERS OF nT.gppMTBT.pg Diameter Class (micrometers) Filament Min Average Maximum A 1.52 2.03 2.54 B 2.54 3.19 3.19 C 3.81 C 3.81 4.45 5.08 D 5.08 5.72 6.35 E 6.35 6.99 7.62 F 7.62 8.26 8.89 G 8.89 9.53 10.16 H 10.16 10.80 11.43 J 11.43 12.07 12.70 K 12.70 13.34 13.97 L 13.97 14.61 15.24 M 15.24 15.88 16.51 N 16.51 17.15 17.78 OR 17.78 18.42 19.09 P 19.09 19.69 20.32 Q 20.32 20.96 21.59 R 21.59 22.23 22.86 T 22.86 23.50 24.13 U 24.13 24.77 25.40 An important beneficial aspect of the present invention is the low weight of the felt product, i.e., 0.15-0.23 kg / m2 (15-23 pounds / 480 square feet). By reducing the weight of the sheet and increasing the percentage of glass fiber, the amount of cellulose is significantly reduced, which provides the product with significantly improved dimensional stability. The reduction in weight alone usually leads to an unacceptable decrease in wear resistance. Unexpectedly, the use of the present composition, with an increased percentage of glass fibers, particularly longer glass fibers, provides a high wear resistance and a light weight canvas felt. The present sheet felt is economically prepared by providing an aqueous suspension of the above composition (a) - (d), which forms a sheet in a felt mill, pressed, drained and dried from the resulting canvas for subsequent winding in a size of proper roll. Due to the lightness and flexibility of the current laminate material, it can easily handle larger sized rollers based on a weight of 0.15-0.23 kg / m2 (15 to 25 pounds / 480 square feet); while most of the previous materials have a weight of 0.27 kg / m2 (27 pounds or more / 480 square feet) and are limited to smaller roller sizes resulting in frequent seams and patches when installed. As the underlying sheet metal layer or as a foamed core, the felt sheet thicknesses may vary from about 1.6 to 22 μm (0.3 and about 4 mils) although thicker canvases may be used for certain applications, when desired . The benefits of increasing feet per roll, that is, an increase of up to 33% linear feet per roll, are carried out by reducing shipping costs and a lower production of stabilization for the consumer. As the covering sheet for an insulation board, the rolled felt sheet of the invention, prepared on a paper line, is sent to insulation fabrication where foam chemical precursors or chemicals are poured onto the uncoiled lower faces of the sheet. felt laminate. As the foam spreads, it enters a laminator where it is brought into contact with the restricted top face of the felt laminate and gummed therein, after which the resulting sheet can be cut into boards. Due to the reduced thickness of the current felt laminate, a significantly greater chemical flow of foam is observed and an increased in-line cure speed through the thinner facing sheet. It is also noted that the greater porosity of the current felt laminate provides significantly stronger adhesion to the foam core and at the same time prevents appreciable shifts in highly functional cores such as those made of polymeric isocyanate. Surprisingly, the thinner felt sheets, using a larger dimensional proportion of glass fibers as described herein, provide significantly increased tear resistance and up to 50% improved dimensional stability. The felt of the invention is especially useful as felt veneer sheet for rigid foamed insulation boards such as those used in the formation of interconstructed roofing (BUR) in roofing boards and as a foam insulation liner used in the lining of walls. Such boards have a core of conventional rigid closed cell foam material, the cells of which normally contain hydrofluorocarbons or hydrocarbon gases. Based on the proposed use, such boards normally have a core thickness of between about 25 and about 100 millimeters. The boards of the invention can be manufactured in a conventional manner with rigid foam which is preferably formed and cured in contact with felt of the invention so that the resulting coating sheet is continuously adhered to the rigid foam core. However, it is possible to form the core without a coating plate and subsequently join it to one or more core coating plates using suitable adhesives. In general, the teachings of U.S. Patent No. 4,351,873 to the formation of rigid foam cores and the adhesion of the coating plate to at least one face of such cores are applicable. The distinguishing feature of the insulation boards of the present invention is the use of felt of the invention as a coating sheet on conventional rigid foam cores. Polyurethane or polyisocyanurate foams are more commonly used, although other foamable polymers known for use in such boards are also suitable. These include polyvinyl chlorides, urea, formaldehyde and polymers of melamine, polystyrene, polypropylene, polyethylene, epoxy resin, acrylonitrile-butadiene-styrene copolymer, cellulose acetate, etc. Rigid foam cores of this type are well known and are described in numerous patents including U.S. Patent No. 4,351,873, the disclosure of which is incorporated herein by reference. Generally, the cladding sheets used in conventional foamed insulation boards have not been economical and tend to have weak adhesion to the foam core. This has resulted in various problems, especially in the manufacture of interconstructed roofing (BUR). In applications such as BUR, foamed insulation boards faced with felt saturated with conventional asphalt are susceptible to winding due, at least in part to the dimensional instability of the siding, and when it is impregnated with hot asphalt materials, the sheet of coating is known to be delaminated from the foam core. Conversely, when the felt product of this invention is used as a coating sheet for a foamed insulation board, the insulation board is less susceptible to winding under variable humidity conditions. In addition, the current coating sheet has strong adhesion to the foam, is resistant to delamination under all conditions and particularly when the board is impregnated with hot asphalt in a finishing process. The felt and insulation board products of this invention also have a wide sphere of application in roofing systems where material compatibility is necessary. For example, it is generally considered unacceptable to allow direct contact between an insulation board faced with conventional asphalt-containing felt veneers in a single membrane of polyvinyl chloride sheet due to migration of the plasticizer. The felt veneered insulation board of this invention presents no problems with respect to the migration of plasticizer since it does not contain asphalt. In addition, conventional asphalt felt cladding sheets of smaller dimensional proportions of glass fiber which have been used for insulation boards, have lower fire resistance and do not retain the integrity of main sheet structure when burned.; while the felt insulation boards of this invention have fire resistance characteristics generally improved due to the lower fuel value per unit area and greater sheet integrity after burning. These characteristics are especially desirable in foamed insulation board cladding sheets in BUR systems. Additionally, the conventional underlying material of the asphalt type is generally deficient in porosity and often does not allow a desirable high transmission of water vapor necessary to maintain the roof covering or protection and the underlying dry insulation. Surprisingly, the product of the present invention will transmit steam at about 10 to 20 times the speed of the conventional felt veneer sheet or the underlying material and at the same time remain as impermeable to liquid water as conventional products. A common problem when using foamed insulation boards, especially those with foamed polyurethane or polyisocyanurate cores faced with asphalt saturated felt facing sheets, is that blistering of the coating sheet may occur when it is impregnated with hot asphalt at approximately 260 °. C (500 ° F). Such blistering takes the form of bubbles in the insulation board, thus improving the delamination presentation of the polyurethane foam. In the manufacture of urethane foam boards an integral polyurethane or polyisocyanurate film is formed between the coating sheet and the actual foam matrix. Blistering occurs under the film when the expanded gases can not escape into the atmosphere and therefore bubbles form. In the present invention, such bulking can be eliminated by perforating the boards after manufacture, ie, after the boards have been formed and the covering sheets have been fixed. Such perforations are preferably in the form of small holes of approximately 0.5-2.5 mm (0.02-0.1 inches) in diameter, spaced from about 6.3 mm (1/4 inch) to about 38 mm (1.5 inches) from their centers and should be of sufficient depth so that both the coating plate and the integral urethane film are perforated. Suitable cellulosic fibers for use in the products of this invention include any of the cellulosic fibers commonly used in the manufacture of cellulose felts of the type conventionally used as underlying layers and veneers for insulation boards, and may include, for example, fibers derived from wood, paper, rags, etc. For economic reasons, scrap paper such as scrap newspaper, scrap kraft corrugated paper, etc. is often used. Mixtures of long and short cellulosic fibers are preferably used in order to provide the felt with the desired porosity. In this regard, the preferred mixtures contain between about 25 and about 75% by weight of short fibers and between about 25 and about 75% by weight of long fibers. Fibers of the type normally used to produce newsprint are a suitable source of short fibers, and fibers of the type normally used in the production of kraft paper can be the source of long fibers. Suitable short fibers typically have lengths between about 0.5 and about 1.5 millimeters and about 3.5 millimeters. The binder used for the felt of the invention uses amounts between about 4 and about 10% by weight, based on the dry felt composition with between about 4 and about 6% by weight of the same base being preferred. Suitable binders include, for example, acrylamides, starch, urea resins, phenol resins, sodium silicates, epoxy resins, etc. Other suitable binders include styrene / butadiene rubber (SBR), latex as well as acrylic, neoprene, acrylonitrile or other natural or synthetic latexes. SBR latex is a preferred binder and, more desirably, is a carboxylated type of SBR latex substantially free of surfactants. One such preferred SBR latex, for example, is one made by continuous addition monomer without the use of surfactant as described, for example, by U.S. Patent No. 4,378,272 and which is incorporated herein by reference. Such latexes not only function as a binder for the felt of the invention but also act as an ion exchange resin to help alleviate the accumulation of certain undesirable materials in closed-loop systems for felt manufacture. However, other binders such as those mentioned above may be substituted in whole or in part. The sizing agent, which replaces the asphalt quota previously used in felt compositions, for example, up to 20% by weight, is bifunctional insofar as it provides both body and water tightness to the present felt composition. Suitable sizing agents have a flash point greater than 65 ° C (150 ° F) and are highly stable and have an evaporation rate of less than 1. More specifically, the sizing agents of the present composition are described in WET END CHEMISTRY, AN INTRODUCTION by William E. Scott, Chapter 4. "Internal Sizing", pages 23-27, published by TAPPI PRESS, 1992, the description of which is incorporated herein by reference. The sizing agents described in the text include acidic and alkaline, fortified organic sizing materials, for example fortified with maleic anhydride and unfortified organic sizing materials having a pH from about 3.5 to about 10 and an acid number from 0 to approximately 200, materials which have superior resistance to water penetration. The sizing component of the present invention is introduced into the composition as a dispersion, suspension, colloid or aqueous emulsion having a solids content of between about 30 and about 70%, preferably between about 40 and about 60%, and is present in the total composition of the preformed felt sheet at a concentration of from about 50% to about 80% by weight, preferably from about 60 to about 70% by weight. Generally, the sizing component is a mixture of an acidic compound, for example, alumina and a rosin derived from rubber, wood or tall oil. These colophonies contain normal and isomeric mixtures of abietic and / or pimaric acids in a fortified or unfortified condition. Other suitable sizing materials include unfriendly cellulose reactive compounds which contain C16 to C30 hydrocarbon chains such as, for example, an alkyl-methane dimer, an alkenyl succinic anhydride, and mixtures of the foregoing or intermixed with rosin / alumina. The commercially available compound ALPHASIZE ", supplied by American Cyanamid Co., is an example of a preferred anionic sizing agent used in this invention Alternatively, an alkaline component may be substituted in whole or in part by the acid component to provide an Suitable cationic sizing agent for the composition Such sizing agents generally have a pH from about 7 to about 10 and are resistant to acidic and alkaline penetrants, however, these cationic agents are susceptible to deterioration and the compositions containing them should not to be stored for extended periods The sizing agent used in the felt composition eliminates the biological incrustation of equipment in the preparation of the felt and contributes to a lighter weight of the felt material, so it allows the final product to roll in a significantly longer length. It is also noted that the replacement of the conventional asphalt component with the current sizing unexpectedly provides faster on-line production and even rapid dispersion of the core compositions on the felt load.

In addition to the required ingredients of the felt composition described above, other conventional adjuvants used in the manufacture of felt can also be included. For example, conventional flocculants, defoamers, precipitants, etc. can be included. Illustrative of suitable flocculants is a cationic acrylamide polymer of high molecular weight such as Betz 1260, which can be used in amounts of between about 227 g ( 1/2 pounds) and approximately 3.6 kg (8 pounds) per ton of dry felt. Representative precipitants optionally used herein include multivalent metal salts or synthetic polymers, pigment can also be used for optional dyeing of the felt of the invention. A preferred pigment is carbon black which can be fixed to the felt matrix with multivalent salts or polymeric flocculants. Desirably, any pigment used should not run when the final product is moistened in water during extended periods of time. Many other modifications and additions to the present felt sheet formulation will become apparent from this description. Having generally described the invention, reference is now made to the following examples which illustrate a preferred embodiment and prepare the following composition with a conventional sheet felt composition. However, the example should not be considered as limiting the scope of the invention as described more broadly in the foregoing and as defined in the claims.

EXAMPLE Felt sheets are produced in a commercial papermaking equipment by forming a felt sheet of an aqueous suspension of the following formulations (A and B) and pressing the formed sheet and allowing the sheet to drain for about 3 minutes before drying. a temperature of approximately 300 ° C.

TABLE A Formulation (based on U.S. Patent No. 4,543,158) PERCENT IN WEIGHT M K Fiberglass (diameter) 13.0 ± 1 18.0 Average length of glass fiber (mm) (inch) 6.35 (1/4) 12.7 (1/2) Newspaper waste 39.5 ± 2.0 37.0 tv > OR Corrugated Kraft waste 39.5 ± 2.0 37.0 Latex SBR 5.0 ± 1.0 5.0 Asphalt (in 50% solids emulsion) 1.0 ± 0.1 - ALPHASIZE 120 emulsion (50% solids) • ± 0.1 1.0 Carbon black 2.0 ± 0.1 2.0 alumina 32 + 2.3 kg (70.0+ 5.0 lbs) / ton of felt Flocculant 0.91 ± 2.3 kg (2.0 ± 5.0 lbs) / ton of felt Formation of glass spheres in the online process (Number of spheres after 8 hours) 200 10 The characteristics of the previous dried felt canvases are presented in the following table B.

TABLE B FORMULATION A B Weight (kg / m2) (pounds / 480 square feet) 0.27 kg / m2 (27.0) 0.20 (19.5) Caliber (μm) (1/1000 inches) 584 μm (23.0) 432 / j? (17U Tear strength CMD * (grams / force) 301 340% ash content * 17.6 23.5 % expansion CMD 1.0 0.5 Adhesion foam (kg / cm2) (pounds / square inch) 0 0..003355 ((88..00)) 0.70 (10.0) Linear meters / roll (linear feet / roll) 2,012 (6,600) 2,652 (8,700) The higher the% of ash indicates better fire resistance. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (16)

1. REYPPICACIQNES 1. A light weight felt composition, suitable for wall covering and underlying roofing of an insulation board covering sheet, characterized in that it comprises, on a dry basis: (a) 60-80% by weight of cellulose fibers; (b) 15-30% by weight of glass fibers having a fiber diameter not exceeding 14 microns and a fiber length of 9.5-19.5 mm (3/8 to 3/4 inches); (c) 4-10% by weight of binder; and (d) 0.5-10% by weight of non-asphalt water-repellent sizing agent having a flash point greater than 65 ° C (150 ° F) and an evaporation rate of less than 1, which is selected from the group of anionic rosin sizes and unfriendly sizes, from C16 to C30 and mixtures thereof.
2. 2. The felt according to claim 1, characterized in that the binder is latex.
3. 3. The felt according to claim 2, characterized in that the latex is SBR.
4. 4. The felting composition according to claim 1, characterized in that the water-repellent sizing agent is selected from the group of anionic and cationic sizing agents, and mixtures thereof. The felting composition according to claim 1, characterized in that the sizing agent is an alumina sizing agent / rosin. The felting composition according to claim 1, characterized in that the concentration of the sizing agent in the total composition is between about 0.8 and about 2.5% by weight. The felting composition according to claim 1, characterized in that the component (b) has a fiber dimension ratio of between about 600 and about 1450, and a filament diameter of from about 5 to about 16.
5. 5. The felting composition according to claim 7, characterized in that (b) has a filament diameter from about 8.8 to about 14. 9. The felting composition according to claim 1, characterized in that the component (a) They are paper waste consisting of fibers of at least 50% length of 1.5-3.5 millimeters. 10. The felting composition according to claim 9, characterized in that the paper waste is a mixture of newsprint and corrugated kraft paper having mixed fiber lengths of between about 0.5 and about 1.4 short fibers and between about 1.5 and about 3.5. of long fibers. The felting composition according to claim 1, characterized in that it is in rolled form and has a weight between about 0.15 and about 0.23 kg / m2 (15-23 pounds / 480 square feet). 12. An insulating board, characterized in that it has a foam core laminated on a felt sheet having the composition according to one of claims 1 to 10. The insulating board according to claim 12, characterized in that the core foaming is a polymer of urethane, isocyanurate, vinyl chloride, urea-formaldehyde and melamine, styrene, an alkylene of C2 to C3, epoxy, acrylonitrile-butadiene, styrene or cellulose acetate, and mixtures thereof. 14. The insulating board according to claim 13, characterized in that the foamed core is polyurethane or polyisocyanurate. 15. The aqueous composition according to claim 1, characterized in that it additionally contains an adjuvant selected from the group of a flocculant, a defoamer, a coloring agent and / or a defoamer. The composition according to claim 1, characterized in that it additionally contains from about 907 g (2 pounds) of flocculant / ton from (a) + (b) + (c) + (d) to about 32 kg (70 pounds) ) of alumina / ton of (a) + (b) + (c) + (d). SUMMARY OF THE INVENTION The invention relates to a felt sheet material of light weight suitable for use as a roof and underlying board and additional facing insulation which comprises, on a dry basis: (a) 60-80% by weight of cellulose fibers; (b) 15-30% by weight of glass fibers having a diameter of 5 to 16 micrometers and a length of 9.5-19 mm (3 / 8-3 / 4 inches); (c) 4-10% by weight of binder and (d) 0.5-10% by weight of non-asphalt sizing agent having a flash point greater than 65 ° C (150 ° F) and a lower evaporation rate of 1, which is selected from the group consisting of anionic colophonic and amphipathic esters and anhydride preparations and mixtures thereof. The felt of this invention is of a considerably lighter and more porous weight compared to other felt materials used for the same purpose and can be supplied in rolls of continuous sheet larger than those hitherto practical from the point of view. view of handling, transport, storage and installation. In addition, the current foil felt can be produced in conventional felt-making equipment, in a one-stage process.