Patent Application
20140318034
1. Field
The present disclosure relates to a rounded ridge cap with asphaltic foams.
2. Discussion of the Related Technology
Generally, ridge caps are installed over the ridge line or the hip line of a roof to provide sealing between two slopes of the roof. The ridge caps may also provide aesthetic looking to the roof. The ridge caps can be made of various materials, for example, metal, tile, or asphaltic foam material.
Many attempts have been made to incorporate asphalt into polyurethane foams. Primarily, asphalt has been used as a filler material for such foams, due to the fact that it is less expensive than the precursor chemicals used to produce polyurethane foam. For example, in Spanish Patent Application No. 375,769, a process is described in which asphalt powder is added to a polyurethane precursor mixture as a filler material. The asphalt powder and polyurethane form a uniformly distributed plastic mass.
The addition of asphalt to a polyurethane foam can also, however, impart certain desired characteristics to the foam. In Japanese Patent Application No. 76/64,489, for example, a polyurethane foam was waterproofed through the addition of asphalt to the polyurethane precursors. Another asphalt-polyurethane mixture having good sound absorption and anti-vibration properties is disclosed in Japanese Patent Application No. 77/68,125.
Most prior art processes for incorporating asphalt into polyurethane, such as Japanese Patent Application No. 76/64,489, have made use of soft asphalts with low softening points. Such asphalts can be liquefied and blended with polyols at relatively low temperatures to form a uniform, liquid mixture of asphalt and polyols. By completely blending the liquefied asphalt with the polyols, a uniform asphalt-polyurethane foam product can then be produced. In addition, because low softening point asphalt remains liquid at relatively low temperatures, the asphalt-polyol mixture can be reacted to form a foam at temperatures which are low enough that a controlled reaction can take place. However, such foam products generally have a relatively low asphalt content.
In Japanese Patent Application No. 76/64,489, for example, a soft asphalt having a needle penetration degree of 80 to 100 is used. This asphalt has a correspondingly low softening point of under 150°. In the process of this patent, the asphalt is mixed with polyurethane precursors, and this mixture is then reacted to form a compressible product, i.e. a soft foam.
The use of such soft asphalts in prior art processes is acceptable when it is desirable for the resulting product to be a soft foam. However, in certain applications, a rigid asphaltic polyurethane foam would be advantageous. A process for making a rigid asphaltic polyurethane foam is disclosed, for example, in U.S. Pat. No. 4,225,678 to Roy. In this process, relatively high molar ratios of isocyanate to polyols are recommended, in some cases as high as 11:1. The Roy process therefore resulted in products which were too friable and/or which lacked sufficient compressive strength. When conventional roofing asphalt having a softening point of over 200° F. was used in the Roy process to produce asphaltic foams, the foaming reaction also was too fast, making manufacturing of asphaltic foams impracticable.
In U.S. Pat. Nos. 5,786,085; 5,813,176; 5,816,014; and 5,965,626 all to Tzeng et al., and U.S. Pat. No. 8,017,663 to Thagard et al., all herein incorporated by reference, an asphaltic foam useful in roofing applications is disclosed.
Various asphalt-coated or asphalt-impregnated materials are in common use in the roofing industry. For example, water absorbent paper which has been saturated with low softening point asphalt, known as saturated felt, is usually placed underneath other roofing components. The asphalt of the saturated felt provides the felt with secondary water repellency.
Higher softening point asphalt is put on either side of saturated felt to form base sheets, which go under the tiles of a roof to build up the roof system. Base sheets with mineral surfacing on their upper surfaces, known as mineral surface rolls, provide enhanced durability and fire retardancy to a roof and can also enhance a roofs appearance. Mineral surface rolls have been used as ridge caps, the largely ornamental structures which straddle the peak of a roof.
However, asphalt-impregnated papers suffer from various drawbacks. When used as ridge caps, for example, mineral surface rolls must be bent to fit the ridge-line of a roof. Mineral surface rolls are also sometimes bent to make them thicker and give a ridge-line a layered appearance. Bending a mineral surface roll causes the asphalt and substrate to crack, however, leaving the cracked material exposed to the elements. The mineral surface roll tends to deteriorate at the site of such cracks within 3 to 4 years of being installed or even sooner, resulting in leaks and other roof damage.
Alternative materials, such as rubberized asphalt with a flexible polyester substrate, have also been used in the roofing industry. For example, modified asphalt has been used in mineral rolls to avoid cracking the asphalt and its substrate.
One method for combining a polyurethane foam and an asphaltic material in roofing applications is suggested in U.S. Pat. Nos. 5,232,530 and 5,305,569 to Malmquist, et al. These patents teach that a polyurethane foam can be attached to the underside of an asphaltic material in order to produce a roofing shingle. Of course, this involves the manufacturing step of physically attaching the foam to the asphaltic material or otherwise forming the foam on the asphaltic material. The polyurethane foam and asphaltic material layers can, in addition, become delaminated.
One aspect provides a method of making a rounded ridge cap, which can comprise: providing an intermediate product comprising a plurality of sections arranged side by side and integrated as a single body of an asphaltic foam material, each of the plurality of sections comprising a rounded top surface, the plurality of sections comprising first and second sections immediately neighboring each other, wherein the first section comprises a first side and the second section comprises a second side integrated with the first side to form a bridge portion between the first and second sections; and bending the first section with respect to the second section about the bridge portion, thereby forming a rounded ridge cap comprising a rounded exterior surface, wherein the rounded top surfaces of the first and second sections form together the rounded exterior surface of the rounded ridge cap.
In the foregoing method, providing the intermediate product may comprise: providing a reaction mixture comprising an asphalt in an mold; subjecting the reaction mixture to react to form the asphalt foam material; and curing the asphaltic foam material, thereby molding the single body of the intermediate product in the mold. The method may further comprise detaching the molded intermediate product from the mold, wherein the bending is performed immediately after detaching. The bending may be performed at a temperature of the molded intermediate product ranging from about 120° F. to about 170° F. The method may further comprise, subsequently to bending, additionally curing the asphaltic foam material.
Still in the foregoing method, providing the intermediate product may further comprise: providing a conveyor belt; applying a granule layer to said conveyor belt; and placing the reaction mixture and the mold over the conveyer belt. Providing a reaction mixture may comprise: providing the asphalt and one or more isocyanates, thereby forming a first intermediate mixture; forming a second intermediate mixture comprising one or more polyols, a blowing agent, and a surfactant; and mixing said first intermediate mixture with said second intermediate mixture, thereby forming the reaction mixture.
Yet in the foregoing method, the top surfaces of the plurality sections of the intermediate product may form an undulating top surface of the intermediate product. The intermediate product may comprise a notch located between the first and second sections and under the bridge portion. Each of the first and second sections of the intermediate product may comprise a wall comprising the rounded top surface, wherein the walls of the first and second sections are integrated at the bridge portion, wherein the bridge portion may have a thickness smaller than that of the wall.
Further in the foregoing method, the first and second sections may comprise a first and second stop surfaces, respectively, wherein the first section may be bent with respect to the second section until the first and second stop surfaces contact to each other. The first and second sections may comprise male and female latches, respectively, wherein the first section may be bent with respect to the second section until the male and female latches are engaged with each other. The rounded exterior surface of the rounded ridge cap may have a substantially semi-circular shape in a cross-section perpendicular to a length direction of the rounded ridge cap.
Another aspect provides a rounded ridge cap, which may comprise: a rounded exterior surface; and a plurality of sections arranged side by side and integrated as a single body of an asphaltic foam material, each of the plurality of sections comprising a wall with a rounded surface portion, wherein the rounded surface portions of the plurality of sections configured to form together the rounded exterior surface, wherein the plurality of sections comprising first and second sections immediately neighboring each other, wherein the first section comprises a first side and the second section comprises a second side integrated with the first side to form a bridge portion between the first and second sections, wherein the bridge portion has a thickness smaller than that of the wall of each of the first and second sections.
In the foregoing ridge cap, the wall of the first section may comprise a first stop surface and the wall of the second section may comprise a second stop surface contacting to the first stop surface and located under the bridge portion. The first section may comprise a male latch and the second section may comprise a female latch engaged with the male latch. The rounded exterior surface comprises granules embedded therein. The rounded exterior surface may have a substantially arcuate shape having a central angle ranging from about 90° to 270° in a cross-section perpendicular to a length direction of the rounded ridge cap. The rounded exterior surface has a continuously rounded shape throughout the rounded exterior surface.
Embodiments of the invention will be described in detail.
Referring to
In embodiments, a rounded ridge cap is made with an asphaltic foam material. Referring to
Subsequently, the sections of the intermediate product are bent to interlock the sections and form a complete round shape of the ridge cap. After bending, the product is cooled to room temperature and cured into a final product of the rounded ridge cap having a sufficient rigidity. In embodiments, the cooling can be completed by placing the bent product at room temperature.
Referring to
Referring to
Referring to
Each of the side sections also includes elevated portions 68 and ribs 70 raised from the bottom of the wall 64. As show in
In one embodiment, the ribs can provide secure contact with the roof having an angle of about 140° between two inclined roof surfaces. In some embodiments, the ribs can provide secure contact with the roof having an angle of about 100° to about 170° between two inclined roof surfaces.
In the foregoing embodiments, the number of the sections is three (3). In other embodiments, the number of the sections of the ridge caps 10 can be modified. For example, in an alternative embodiment, a ridge cap can have only two sections which can be bent to form a single rounded shape of the ridge cap. Alternatively, a ridge cap can include four or more sections.
Referring to
In embodiments, the notch 78 may be formed by a first stop surface 78a of the side section 54 and a second stop surface 78b. When bending the sections 52 and 54, the stop surfaces 78a and 78b become contact to each other. Such configuration can limit the excessive bending. The contacting stop surfaces 78a and 78b in the finished rounded ridge cap may have a length Tb in a thickness direction of the top walls of the sections 52 and 54 smaller than the thickness T of the top walls of the sections 52 and 54.
The connecting bridges 76 can be deformed to allow each of the side sections to be bent with respect to the middle section at a warm temperature (for example, about 140° F.) higher than a room temperature without generation of substantial cracks around the connecting bridges 76. However, once the cooling process is completed, the connecting bridges 76 become rigid sufficiently to maintain the whole shape of the final product of the ridge cap 10 as shown in
Referring to
Each of the locking mechanisms includes a male latch 72 and a female latch 74. As shown in
Referring to
Referring to
As used herein, the terms listed below shall be defined as follows, unless a contrary meaning is clearly meant in context:
“Foaming reaction” shall mean a sum of chemical reactions that concur when a polyisocyanate is put in contact with a polyol and water to form a polyurethane and carbon dioxide as a blowing agent.
“Modified asphalt” shall refer to asphalt which has been blended with polypropylene, particularly atactic polypropylene, or with other asphalt modifiers such as styrene-butydiene-styrene (SBS) or Vistamer™, a surface modified particulate rubber.
“Penetration” shall mean the hardness of a material, as measured by the resistance of the material to penetration by a needle mounted on a penetrometer. A penetrometer is a device which holds a needle with a 100 gram (+−0.05 grams) load and moves vertically without measurable friction. To determine the penetration value of a material, the tip of the needle of a penetrometer is positioned on the surface of a material whose hardness is to be tested, and the needle is allowed to penetrate into the material for 5 (+−0.1) seconds at 77° F. (25° C.). The amount of penetration is rated in terms of the length of the needle, measured in tenths of millimeters, which penetrated the material in those 5 seconds. A numeric value corresponding to amount of penetration, in tenths of millimeters, is then assigned as the penetration value of the material. This procedure follows the standard test method for the penetration of bituminous materials promulgated by the American Society′ for Testing and Materials (ASTM Designation D 5-83). Since a needle will pass through a softer material more rapidly than a harder material, higher penetration values correspond to softer materials.
“Reaction mixture” shall refer to any combination of reactants used in the process of the embodiments prior to being reacted in a foaming reaction.
“Softening point” means the temperature at which asphalt attains a particular degree of softness. Asphalt does not have a definite melting point, but instead changes slowly from a harder to a softer material with increasing temperature. The softening point is determined by placing a steel ball (9.53 mm in diameter) on a mass of asphalt contained in a brass ring. The ring has a brass plate at the bottom in contact with the asphalt sample. The asphalt and ball are then heated in a water or glycerol bath until the ball drops to the plate, which is 25 mm under the ring. The temperature at which the ball drops to the plate is the softening point. This procedure follows the standard test method for the softening point of bitumen promulgated by the American Society for Testing and Materials (ASTM Designation D 36-76).
The previously discussed definitions pertain as well to other grammatical forms derived from these terms, including plurals.
Asphalt is a solid or semisolid mixture of hydrocarbons and small amounts of non-hydrocarbon materials, occurring naturally or obtained through the distillation of coal or petroleum. Most of the hydrocarbons in asphalt are bituminous, meaning that they are soluble in carbon disulfide. As is known to those of skill in the art, asphalt is a complex, colloidal mixture containing a broad spectrum of different hydrocarbon components. These components can generally be broken down into three main categories: two solid components, the asphaltenes and asphaltic resins, and one liquid component, the oily constituents.
Asphaltenes generally comprise the highest molecular weight and most aromatic components of asphalt. Asphaltenes are defined as the components of asphalt which are soluble in carbon disulfide but insoluble in paraffin oil (paraffin naphtha) or in ether.
Broadly categorized, the asphaltic resins and oily constituents can be further separated into saturated components, aromatic components, and resins or polar components. The polar components are responsible to some degree for the viscosity of an asphalt.
In order to produce an asphaltic foam of the embodiments, asphalt meeting certain specifications can be used in the process for manufacturing this foam. We have found that the hardness of the asphalt component of the foam contributes to the rigidity of the final foam product. Therefore, in order to give the final product sufficient rigidity, an asphalt having a penetration range of about 5 to about 25 can be chosen. In one embodiment, an asphalt having a penetration range of between about 8 and about 18 is used, and in another embodiment, an asphalt having a penetration of about 12 is used. However, in order to keep the reactants at a lower temperature range (about 120° F.-170° F.) where the reaction rate is controlled, asphalt with a penetration range of about 90-110 and softening point of about 110° F. can be used.
The hardness of asphalt is, in turn, generally correlated to its asphaltene content, although the asphaltic resin components of asphalt will also contribute to an asphalt's hardness. The asphalt used to produce the foam of the embodiments has an asphaltene content in the range of about 10% to about 30% by weight, in another embodiment, in the range of about 12% to about 18%. In a particular embodiment, the asphalt used in the embodiments has an asphaltene content of about 12%.
The asphalt used to produce the present asphaltic foam can be chosen so as to have a relatively low softening point. An asphalt having a softening point of about 100° F. to about 200° F. can be used. In one embodiment, an asphalt having a softening point of about 100° F. to about 150° F. is used, and in another embodiment, an asphalt having a softening point of about 120° F. is used. As is known to those of skill in the art, the softening point of asphalt is influenced by the resin or oil content of the asphalt.
In one embodiment, the asphalt used to produce the present asphaltic foam, in addition, is chosen so as to have a lower viscosity. The lower viscosity can be achieved with or without the use of viscosity reducers.
An asphalt for use in the embodiments is a non-blown (i.e., not air-oxidized) asphalt obtained from Paramount Petroleum (California) having the following specifications: a softening point of greater than about 90° F. and less than about 120° F., and a penetration range of greater than about 85 and less than about 120. This asphalt is composed (in weight percentages) of about 0.12-13% asphaltene, about 9-12% saturated hydrocarbons, about 38-44% polar aromatics, and about 35-38% naphthalene aromatics. For example, Saturant 701 asphalt meeting these specifications can be used. The use of one of the previously discussed asphalt is advantageous such that with mixing of the asphalt and isocyanate, flaking or boiling off of the components would not occur. Additionally, a use of one of the previously discussed asphalt will result in an asphaltic foam that is more flexible.
In total, the asphalt component of the reactants used in the process of the embodiments can comprise up to about 24% by weight of the final finished product. Asphalt can, however, make up between about 5% and about 33% of the finished product used in the present process.
The use of lower amounts of asphalt in the process of the embodiments will not significantly affect the reaction of that process. However, using greater amounts of asphalt than this can lead to the reaction mixture becoming more viscous (in the absence of viscosity reducers), necessitating the use of higher reaction temperatures in order to blend the reaction mixture components. This in turn increases the reaction rate to a point which becomes hard to control during manufacturing.
Generally, the more asphalt used, the more economical the final product will be, since asphalt is generally less expensive than the other components of the present asphaltic foam. Asphalt does, however, require energy to heat it. Higher asphalt levels will also lead to higher viscosity in the reaction mixture, which may cause manufacturing difficulties.
In addition, the amount of asphalt used will affect the physical properties of the finished asphaltic foam product of the embodiments. With a higher asphalt content, the foam tends to be softer and to have a higher density. More free asphalt can also be extracted from the foam at higher asphalt levels.
When producing the asphaltic foam of the embodiments, it is possible, though not essential, to blend an asphalt modifier into the asphalt component of the reaction mixture. For example, the addition of polypropylene to the asphalt enhances the strength of the final foam product of the present process. In one embodiment, atactic polypropylene (APP) is used because it blends well with the asphalt.
When polypropylene is used in the present process, it is blended into the asphalt component of the reaction mixture in an amount of up to about 10% by weight of the asphalt. In one embodiment, polypropylene is added in an amount of between about 3% and about 8%, and in another embodiment, is used in an amount of about 5% by weight of the asphalt.
In order to blend the polypropylene into asphalt, the asphalt is first heated to about 400° F. The polypropylene is then dropped into the hot asphalt and blended in with a mechanical mixer. Atactic polypropylene typically has a melting point of over 350° F. and so will melt on exposure to the hot asphalt.
Other modifiers can also be used in the same way as APP to modify the characteristics of the asphalt and/or the characteristics of the final asphaltic foam product of the embodiments. Such modifiers include isotactic polypropylene (IPP), styrene-butydiene-styrene (SBS), styrene-isoprene-styrene (SIS), ethylene-propylene (EPM), ethylene-propylene-diene (EPDM), ethylene-vinyl acetate (EVAc), ethylene-acrylic ester (EAC), ethylene copolymer bitumen (ECB), polyethylene (PE), polyethylene chlorosulfonate (CMS), polyvinylchloride (PVC), butyl rubber (IIR), polyisobutylene (PIB), and polychloroprene (CR). If the modifier used has a lower melting point than APP, the asphalt in that case only needs to be heated to a sufficient temperature to cause the modifier to melt and blend into the asphalt and to cause the asphalt to be sufficiently liquid so that other components can be mixed into the asphalt.
One modifier which has been found to be particularly useful is Vistamer™ (sold as Vistamer™ R or Vistamer™ RD, depending on the water content of the particles), which is a surface modified particulate rubber product made by Composite Particles, Inc. (2330 26th St. SW., Allentown, Pa. 18103). Vistamer™ is a free-flowing black powder made from post-consumer tire materials. When added to the asphalt used in the present process in an amount of about 10% (by weight of the asphalt), Vistamer™ not only improves the viscosity of the asphalt and makes it easier to blend the asphalt with the polyol component of the process, it also increases the compressive strength of the final foam product by about 10-15%. Smaller amounts of Vistamer™ can also be added, of course, and this modifier can also be used together with other modifiers, in amounts of up to about 10% total modifier (by weight of the asphalt). Due to the high melting point of Vistamer™, the asphalt is heated to about 400° F. before adding the Vistamer™ to the asphalt.
Polyols are one of the precursors necessary to form a polyurethane or isocyanurate foam. A polyol is a hydrogen donor having a plurality of hydroxyl groups (—OH). Polyols also sometimes comprise other hydrogen donor moieties, such as —NH, —SH, and/or —COOH. NH groups are generally more reactive than OH groups, followed by SH and COOH groups in reactivity. Polyols comprised mainly of —OH hydrogen donors react quickly enough to be commercially feasible but not so quickly as to produce a foaming reaction which cannot be controlled. Polyols comprised mainly of —OH hydrogen donors and polyols with amino groups have been found to be in the present process.
In the foaming reaction of the present process, the polyisocyanate mixed with asphalt prior to reaction, is reacted with a mixture of polyols to form an asphaltic polyurethane or isocyanurate foam (depending on the proportion of polyisocyanate in the mixture). The polyisocyanate/water reaction is employed to form the carbon dioxide gas as blowing agent. Several characteristics of the polyols influence their reactivity in foaming reactions as well as the nature of the foams produced by such reactions. One characteristic of the polyols is its functionality, that is, the number of reactive sites per molecule, such as hydroxyl groups or amino groups, available to react in a foaming reaction.
In embodiments, a polyol having 2 or 3 functionalities can be used to produce the asphaltic foam of embodiments. Alternatively, a mixture of polyols which, in aggregate, have an average of about 2 to about 3 functionalities can be used in the present process. In the present process, the best results have, in fact, been obtained when polyols used in the process comprise a mixture of the following three polyols:
In general, the use of polyol having low functionality, for example, functionality of 2 or 3 rather than high functionality would reduce the cross linking, and thus, would reduce the rigidity during the post-processing of the molded product. A mixture of polyols for use in embodiments comprises Carpol TEAP 265, Carpol GP-6015 and Carpol PGP-1000. In one embodiment, the ratio of Carpol TEAP 265, Carpol GP-6015 and Carpol PGP-1000 (Carpol TEAP 265:Carpol GP-6015:Carpol PGP-1000) by weight can be 1:a:b (a is about 0.6 to about 0.8, and b is about 0.5 to about 0.7). In another embodiment, the ratio of Carpol TEAP 265, Carpol GP-6015 and Carpol PGP-1000 (Carpol TEAP 265:Carpol GP-6015:Carpol PGP-1000) by weight can be 1:a:b (a is about 0.69, and b is about 0.6). The foregoing ratio can provide an intermediate product which is soft sufficient to be deformed or bent before the cooling process, and can also provide a final product having a sufficient rigidity after the cooling process.
There are several other factors to consider when choosing polyols for use in the embodiments. The viscosity of a polyol, for example, is important. In embodiments, less viscous polyols are generally used, since the asphalt component of the reaction mixture is itself highly viscous, and less viscous polyols can help to lessen the viscosity of the reaction mixture. Polyols with a lower equivalent weight can be used for conferring more strength to the foam but a certain amount of high equivalent weight polyols is desirable for bringing in some foam flexibility.
Of course, other polyols besides those enumerated above are available commercially and can be used in the present process. Representative polyols which can be used according to the parameters outlined above include both polyester polyols and polyether polyols. Representative polyether polyols include poly(oxypropyrene) glycols, poly(oxypropylene-b-oxyethylene) glycols (block copolymers), poly(oxypropylene) adducts of glycerol, poly(oxypropylene) adducts of trimethylolpropane, poly(oxypropylene-b-oxyethylene) adducts of trimethylolpropane, poly(oxypropylene) adducts of 1,2,6-hexanetriol, poly(oxypropylene) adducts of pentaerythritol, poly(oxypropylene-b-oxyethylene) adducts of ethylenediamine (block copolymers), and poly(oxypropylene) adducts of sucrose methylglucoside, sorbitol. Representative polyester polyols include those prepared from the following monomers: adipic acid, phthalic anhydride, ethylene glycol, propylene glycol 1,3-butylene glycol, 1,4-butylene glycol, diethylene glycol, 1,2,6-hexanetriol, trimethylopropane and 1,1,1-trimethylolethane. Other polyols which can be used include N,N,N′,N′-tetrakis (2-hydroxy-propyl)-ethylenediamine, which is commercially available under the trade name of “Quadrol” from BASF Wyandotte Corporation.
In order to produce an asphaltic foam product with a greater degree of foaming, compositions referred to as “blowing agents” can be added to the reaction mixture. When added to a reaction mixture, blowing agents are initially liquids. However, blowing agents become gaseous during the foaming reaction and expand in volume. Such expansion causes the now gaseous blowing agents to exert force against the polymerizing reactants, thereby forming bubbles or cells in the final foam product.
One blowing agent which can be used is water. When water is added to the reaction mixture, it reacts with the polyisocyanate in the mixture to give an amine or polyamine and also carbon dioxide. Since water is dispersed homogeneously in the mixture, the carbon dioxide gas is evolved throughout the cell structure. It is advantageous for such carbon dioxide to be formed during the foaming reaction, in order for the bubbles formed by the carbon dioxide to produce the cells characteristic of polyurethane and isocyanurate foams. Therefore, polyisocyanate and water is not mixed together until the foaming reaction is begun.
When water is used as the sole blowing agent in the present process, it is added to the reaction mixture in an amount of between about 0.5% and about 5% by weight; in another embodiment, in an amount of between about 0.7% and about 2.5% by weight; and in another embodiment, in an amount of about 1.3% by weight, based on the weight of the reaction mixture containing polyols. If other blowing agents were added to the reaction mixture in addition to water, a correspondingly lesser amount of water would be added. Excess water is not added, because the water is a reactant and will react with the isocyanate, thereby preventing the isocyanate-polyol reaction. The addition of too much water would prevent a foam cell structure from forming and would cause too much carbon dioxide to evolve.
Other blowing agents used to foam polyurethane or isocyanurate polymers generally operate by vaporizing at temperatures which are lower than that at which the foaming reaction takes place, rather than by reacting with any of the components of the reaction mixture. Such other blowing agents include halocarbons, such as trichlorofluoromethane, dichlorodifluoromethane, and methylene chloride; ethanol mixed with dibutylphthalate; and other volatile liquids or liquid mixtures. Because these blowing agents act by vaporizing, they are generally added, like water, just before the foaming reaction begins. However, we have found that under most circumstances it is not feasible to use such conventional physical blowing agents due to the temperature requirement of the asphalt-polyol mixture, which is highly viscous at lower temperatures.
A number of polyisocyanates can be used to create the asphaltic foam of the embodiments. These polyisocyanates can have at least two and in another embodiment, three functionalities per polyisocyanate molecule.
In the process of the embodiments, polyisocyanates are added to the reaction mixture in a particular stoichiometric molar ratio compared to the amount of polyol added. In order to form a polyurethane asphaltic foam, this ratio can be in the range of about 1.3:1 to 1:1 (polyisocyanate:polyol), and about 1.1:1 in one embodiment. In order to form an isocyanurate foam, though, the ratio can be in the range of about 2.0:1 to 2.5:1, and in another embodiment, can be about 2.5:1. In another embodiment, in order to form a polyurethane asphaltic foam, the polyisocyanate is added to the asphalt in a weight ratio of about 0.8:1 to 3.2:1 polyisocyanate:asphalt, and in a further embodiment, in a ratio of about 1:1 to 1.5:1 polyisocyanate:asphalt.
In an embodiment, a polyisocyanate molecule having about 3 NCO functionalities is used in the process of embodiments. This molecule is a polymeric methylene diphenyl diisocyanate (MDI)-type molecule. Polymeric MDI is due to its low toxicity and low vapor pressure at room temperature. Mondur MR (Miles, Inc.) is a polymeric MDI which has been found to produce a satisfactory asphaltic foam product. Other polyisocyanates which can be used include PAPI 580 (Dow), PAPI 901 (Dow), PAPI 27 (Dow), Mondur E-489 (Miles), Mondur 437 (Miles), Rubinate HF-185 (ICI), and LUPRANATE M70 (BASF).
A variety of other ingredients can be added to the reaction mixture in minor amounts according to the process of the embodiments in order to impart certain desired characteristics to the final asphaltic foam product. For example, in order to assure an even cell structure in the foam material, a silicone surfactant such as Air Products DABCO DC 5357 can be added during the blending of the polyol-asphalt mixture. If up to about 4% of a surfactant (based on the weight of the polyol and asphalt together) is added to the reaction mixture, a foam having smaller, homogenous cells is obtained.
Plasticizers, such as dioctylphthalate, diisooctylphthalate, dibutylphthalate, diisobutylphthalate, dicaprylphthalate, diisodecylphthalate, tricresylphosphate, trioctylphosphate, diisooctyladipate, and diisodecyladipate, can also be used in the present process to make the reactants used in the process less viscous. Plasticizers in this application act as emulsifiers and as viscosity reducers.
In one embodiment, catalysts to speed the foaming reaction are not added when producing a polyurethane foam. It has been found, for example, that catalysts such as triethylamine and triethanolamine cause a foaming reaction which is too rapid to be used in manufacturing polyurethane foam products. However, catalysts which speed the curing of the final foam product are advantageously used. Curing catalysts such as Air Products DABCO 33 LV or POLYCAT 5 can be added in amounts of up to 2% based on the total weight of the polyol mixture.
When producing isocyanurate foams, though, a catalyst can be added to the reaction mixture in order to make the foaming reaction sufficiently rapid to be commercially useful. Between about 8% and 10% (by weight of the polyol mixture) of a catalyst such as DABCO® TMR-4 (available from Air Products and Chemicals, Inc., Box 538, Allentown, Pa. 18105) can be added to the polyol mixture prior to the commencement of the foaming reaction in order to produce a rapidly foaming isocyanurate foam product.
In addition, other additives such as flame retardants, fillers, and U.V. protectors can also be added to the reactant mixture in order to impart other desired characteristics to the asphaltic foam of the embodiments without deleteriously effecting the rigidity and other physical properties which are achieved in the final foam product. For example, the flame retardant Antiblaze® 80 and Fyrol 6 (diethyl-N, N-bis(2-hydroxyethyl)aminomethyl phosphonate) have been successfully incorporated into the asphaltic polyurethane foams of the embodiments to increase the flame retardancy of the foam material. Antiblaze® 80 is a neutral, chlorinated phosphate ester which is available from Albright & Wilson, P.O. Box 26229, Richmond; VA 23260. Flame retardants, if used, are added to the reaction mixture prior to foaming in amounts of about 8% to 10% (by weight of the polyol-asphalt mixture). The flame retardant TCPP (Tris-(chloroisopropyl)phosphate) has also been successfully incorporated into the asphaltic polyurethane foams of the embodiments to increase the flame retardancy of the foam material. Smaller amounts of fire retardant can also be incorporated into the foams of the embodiments, although the amount of fire retardancy imparted to such foams will of course be decreased.
To form the asphaltic foam of the embodiments, the asphalt described above is first heated to a temperature over its softening point, so that polyisocyanate can be mixed homogeneously with the asphalt. The asphalt is heated to about 250-280° F. to assure that the viscosity of the asphalt will be sufficiently lowered to enable proper mixing of the asphalt and polyisocyanate.
Polyisocyanate is added to asphalt to form a first intermediate mixture (Mixture A). When the polyisocyanate is added to the asphalt, the temperature of the reactants will generally be about 120° F. to about 170° F. In order to form a polyurethane asphaltic foam, the polyisocyanate is added to the asphalt in a weight ratio of about 0.8:1 to 3.2:1 polyisocyanate:asphalt, and in another embodiment, in a ratio of about 1:1 to 1.5:1 polyisocyanate:asphalt.
A second intermediate mixture (Mixture B) comprises a mixture of polyols and a blowing agent. In Mixture B, polyols are in amounts of between about 5% and about 100% by weight of the asphaltic foam, though, in another embodiment, they are in amounts of about 32% by weight of the asphaltic foam. Between about 0.5% and about 5%, and in another embodiment, about 1.3% water is added to the Mixture B.
Mixture B can also contain, each as an optional component, a surfactant, catalyst, and fire retardant. A surfactant is DABCO DC 5357 in an amount of about 2.4% by weight of Mixture B. Catalysts are DABCO 33LV in an amount of about 0.1% by weight of Mixture B and POLYCAT 5 in an amount of about 0.7% by weight of Mixture B. A fire retardant is TCPP in an amount of about 8-25% by weight of Mixture B, that is, about 5-10% by weight of total foam mixture.
The chemical process comprises pumping Mixture A and Mixture B at about 1.35:1 ratio and a total flow rate of about 7.4 lbs/min. in 2 impingement dispensing heads. In embodiments, the ratio of Mixture A and Mixture B can be about 1.2:1 to about 1.45:1. The mixed materials can be dispensed on a conveyor that runs continuously and molds can be placed over the mixture. Alternatively, the mixed material can be dispensed directly into a mold. An advantage to the present process is the ability to turn off the machinery at any time. Also, cleaning of the impingement dispensing heads is minimal and with ease. Alternatively, for some applications the foam can also be allowed to rise freely without a mold.
The foaming reaction begins as soon as the polyisocyanate is mixed with the remaining ingredients of the reaction mixture. With segregating polyisocyanate from polyol within Mixture A and Mixture B respectively, the foaming reaction can be controlled by mixing Mixture A (containing polyisocyanate) and Mixture B (containing polyols). With a more controlled foaming reaction, there is less loss of the blowing agent which is able to evaporate otherwise. If the Carpol TEAP 265, Carpol GP-6015 and a diol Carpol PGP-1000 are used as the polyol for this reaction, a moderate, controlled foaming reaction will take place. If other polyols are used, however, some adjustments to the process may need to be made in order to assure a controlled reaction, as outlined above.
The initial stage of the reaction, from the time the Mixture A and the Mixture B come into contact until the time the foam begins to rise, is called the “cream time.” During this stage, the foaming reaction mixture thickens. At about 120° F., cream stage lasts for about 15-20 seconds. Thus, the polyisocyanate and other reactants can be mixed together for no longer than about 2-6 seconds before being placed into a mold. Otherwise, the foam may expand to a point beyond that desired in the final molded product, or may cure before taking on the desired form of the mold.
In the second stage of the foaming reaction, called the “rise time,” the foam begins to expand. During this stage, sufficient CO2 is produced to cause expansion of the foam. In addition, if blowing agents have been added, such blowing agents volatilize at this time, due to the heat created by the foaming reaction. The length of the cream time and rise time of the foaming reaction will depend on the chemical reaction rate, which in turn depends on the temperature of the mixture, the mold temperature, and the temperature of the environment. The foam is cured when the foam surface is no longer tacky, which usually occurs within about 1.5 to 2 minutes.
One of the great advantages of the present process is that it can be performed under the previously discussed conditions, which are sufficiently controlled to be useful in a manufacturing process. Asphaltic polyurethane foams produced by prior art methods were, generally, made using lower percentages of asphalt or softer asphalts, as well as lower reaction temperatures. For this reason, such reactions required catalysts to be commercially useful. However, due to the use of the higher reaction temperatures of the present process, catalysts other than the NH groups which can be present in the polyol cannot be used when producing an asphaltic polyurethane foam according to the embodiments.
Although the reaction can be run at temperatures higher than about 180° F., the speed of the reaction increases ten times for every 10° F. increase in temperature over 180° F. Thus, although the present reaction can be performed at temperatures of up to about 200° F., in another embodiment, such high temperatures are not used due to the greatly increased speed of the reaction and a concomitant increase in the difficulty of manufacture at such increased speed. In the case of certain highly viscous asphalts which can be used according to the embodiments, higher temperatures will help such asphalts to flow better by reducing their viscosity, but, as stated previously, this aid in manufacturing can be balanced against the difficulty of controlling faster reactions.
Using temperatures above about 200° F. is, in most cases, disfavored in the present process. At such higher temperatures, the speed of the foaming reaction becomes unacceptably violent. Nevertheless, in certain formulations higher temperatures can be tolerated.
Generally, the foam takes about 1.5 to 2 minutes to cure once it has expanded to fill a mold into which it has been placed. However, the cure time will depend on the reaction temperature, the type of polyol used, the process environment, and other variables.
In one embodiment, the reaction mixture is placed in a mold (or, alternatively, a mold is placed around the mixture) in order to form a molded article. The asphaltic foams of the embodiments can, in an alternative embodiment, comprise asphaltic polystyrene or asphaltic PVA foams. In such embodiments, the asphalt used in the present process would be mixed with the precursors of polystyrene or PVA in the amounts described previously in connection with the production of polyurethane and isocyanurate foams.
A small batch of an improved asphaltic polyurethane foam is produced as follows and according to Table 1. A non-blown asphalt having a penetration of about 90-110 and a softening point of about 110° F. is first selected. This asphalt is available from Paramount Petroleum. About 1039.5 lb of this asphalt is heated to 250° F. in a container. A Mondur MR polyisocyanate is next added to the asphalt to form Mixture A.
In Mixture B, the polyols are Carpol TEAP 265, Carpol GP-6015 and Carpol PGP-1000. A mixture of about 611.52 lb Carpol TEAP 265, about 419.2 lb Carpol GP-6015 and about 366.08 lb Carpol PGP-1000 is formed. Following this, about 20.8 lb of water is mixed into the reaction mixture. About 131.2 lb of TCPP fire retardant, about 38.4 lb of DABCO DC5357, about 1.6 lb of DABCO 33LV, and about 11.2 lb of POLYCAT 5 was mixed into the reaction mixture. The TCPP fire retardant is an optional component.
Using high pressure rotary piston pumps with a metering ratio of 1.35:1 (Mixture A:Mixture B), Mixture A and Mixture B are pumped at a flow rate of about 5 lb/min/head in 2 impingement heads. Within about 2-3 seconds, this mixture is then deposited in a mold. The mixture begins rising and forming a foam, and after about 60 seconds the foam is completely formed.
In one embodiment, the asphaltic foam of the previously discussed embodiments is formed into an intermediate product 50 of a ridge cap 10 (
The granules are placed on the conveyor belt from a discharge holding tank using a system of dispensing rolls driven by a variable speed electrical motor. This dispensing system drops the granules into a box that holds them directly on the belt. One side of the box is a gate that can be slid up and down allowing a controlled amount of granules to travel away with the belt.
In an embodiment, different solid color granules are gravity fed from 2-3 ton bulk bags into holding tanks or hoppers. From this hopper, the granules are dispensed in controlled ratios on a conveyor belt and from there they are homogeneously colored blended by dropping them several times from one conveyor to another toward the machine holding tank.
A scraper having a wavy surface is held over the granule layer at a predetermined height (corresponding to the desired thickness and shape of the granule layer) in order to assure a granule layer 900 conforming the rounded shape of the intermediate product 50. (See
The asphaltic foam is produced as described in the foregoing in a mold. In embodiments, the mold is heated to about 200° F. Heating of the mold can be accomplished with blowing hot air with a fan. After the asphaltic foam is produced in the mold, the mold containing the asphaltic foam is flipped about 180° so that the top of the mold contacts the granules on the conveyor belt. The asphaltic foam is then compressed and cured onto the granules.
The inside surfaces of the molds used in the embodiments are treated with a spray mold release, such as a silicone based mold release. Alternatively, the inside of the molds can comprise a layer of Teflon® (PTFE) to facilitate the removal of the finished foam product from the molds. Alternatively, a spray mold release comprises motor oil, such as CALISTA 122 motor oil 10W40. Alternatively, a silicone rubber mold can be used without application of a release agent.
An intermediate product 50 of a ridge cap 10 shown in
On a flat, moving conveyor 800 is placed a layer of roofing granules 900. See
After placing the layer of roofing granules on the conveyor surface, the mixed reactants are dispensed on the granules that come with the conveyor belt. The molds, which are heated to about 200° F. are then placed on top of the reaction mixture, which starts expanding and fills the mold cavities. In about 60 seconds the asphaltic foam is totally formed within the mold.
The inside surfaces of the molds used in the embodiments are treated with a spray mold release, such as a spray mold release comprising motor oil, such as CALISTA 122 motor oil 10W40.
In the foregoing, the configuration and the making process of a ridge cap 10 is discussed, but the invention is not limited thereto. U.S. Pat. Nos. 5,786,085, 5,813,176, 5,816,014 and 5,965,626 and 8,017,663 and U.S. patent application Ser. No. 13/207,319 disclose the configuration of ridge caps and the process of making ridge caps. The process and compositions disclosed in the foregoing patents and the patent application can be used or modified to form the ridge cap 10. Thus, the entire disclosure of each of U.S. Pat. Nos. 5,786,085, 5,813,176, 5,816,014 and 5,965,626 and 8,017,663 and U.S. patent application Ser. No. 13/207,319 is incorporated by reference herein.
This application claims priority to and the benefit of U.S. Provisional Patent Application No. 61/718,672, filed Oct. 25, 2012, the disclosure of which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61718672 | Oct 2012 | US |
