MXPA99010184A - Compressible preform insulating liner - Google Patents

Abstract

The invention provides a preform insulating end cone (30, 60) suitable for forming the end cone of a pollution control device (10), said preform (30, 60) comprising a cone shaped intumescent or non-intumescent sheet material (40) with or without a plurality of splits (49) enabling said sheet material (40) to be cone shaped and a shape retaining element in intimate contact with said intumescent sheet material (40), said shape retaining elements enabling said intumescent sheet material (40) to maintain a cone shape. The invention also provides methods of making preform insulating end cones (30, 60) of the invention.

Description

COMPRESSIBLE PREFORM OF INSULATING LINING BACKGROUND OF THE INVENTION The present invention relates to insulating materials used in pollution control devices and more particularly to a method for making a preform of an intumescent or non-intumescent sheet material for use as an insulating end cone in pollution control devices and resulting preform insulating end cones. Two types of pollution control devices are currently widely used - catalytic converters and diesel particulate filters or traps. The catalytic converters contain a catalyst, which is typically coated on a monolithic sculpture mounted on the converter. Monolithic structures are typically ceramic, even though metal monoliths have been used. The catalyst oxidizes carbon monoxide and hydrocarbons, and reduces nitrogen oxides in automobile exhaust gases to control air pollution. Diesel particulate filters or traps are wall flows which have monolithic, honeycomb structures typically made of porous crystalline ceramic material. The alternating cells of the structure in REF .: 31860 honeycomb shape is typically plugged so that the exhaust gas enters a cell and is driven through the porous wall of one cell and leaves the structure through another cell. Due to the relatively high temperatures found in pollution control devices, it is important that the device is well insulated. The insulation is typically provided by securely mounting the monolithic element within the cover using an insulating mounting grid made of a suitable material. In addition, the inlet and outlet end cone assemblies, which provide a transition from the exhaust pipe to the contamination control device, must also be insulated. The inlet and outlet end cone assemblies can be insulated to provide a double wall end cone assembly comprising an outer metal housing and an inner metal housing, with a defined spacing between the inner and outer cone housings.

BRIEF DESCRIPTION OF THE INVENTION One aspect of the invention is an insulating preform in the form of an end cone suitable for forming the end cone of a contamination control device, the preform comprising a shaped cone of intumescent or non-intumescent sheet material having a plurality of grooves. which allow the sheet material to acquire the cone shape, and a shape retaining member in intimate contact with the intumescent sheet material, the retaining element allows the intumescent sheet material to have a cone shape. Another aspect of the invention is an end cone insulating preform suitable for forming the end cone of a contamination control device, the preform comprising a cone-shaped intumescent sheet material having a first end and a second end, and a shape retention element in intimate contact with the intumescent sheet material, the shape retention element allows the sheet of intumescent material to maintain a cone shape. Preferably, the shape retention element in this embodiment is a ribbon joining the ends together. Preferably, the sheet material is coated on a side on which the tape is to be adhered with a thermoplastic polymer film such as polyester, polyethylene or polypropylene. The invention also provides a method for manufacturing an end cone insulating preform for use as an insulating material in an end cone assembly in a contamination control device from a sheet material. In one aspect, the invention provides a method for making an end cone insulating preform comprising the steps of forming an intumescent or non-intumescent sheet material "containing a thermoplastic organic binder and cutting to the desired shape and dimensions to form a finished preform end cone insulation, treating the formed sheet material with water or steam, and then drying the treated sheet material to form the finished end cone insulating preform. Preferably, the cut sheet material is preformed by means of a mold. Preferably, the cut sheet material has a plurality of V-shaped cuts. Preferably, the sheet material is intumescent and has a thermoplastic organic binder derived from a latex. In another aspect, the invention provides a method for making an end-core insulating preform "comprising the steps of treating at least one surface of an intumescent or non-intumescent sheet material, flexible and resilient, with a rigidifying solution, the The material sheet is suitable for use in pollution control devices and is cut to the desired size and shape to form a finished end-cone insulator preform, shape the sheet material into the desired end cone shape, and then dry the sheet material to form the end cone insulating finished preform. The stiffener solutions produced are aqueous colloidal silica and aqueous colloidal alumina. The preferred intumescent and non-intumescent sheet materials contain an organic binder comprising a polymer emulsion. Another aspect of the invention provides a method for making an end cone insulator preform comprising the steps of providing an intumescent or non-intumescent sheet material, flexible and resilient, suitable for use in a contamination control device, coating at less one side of the sheet material with a metal sheet and then forming the coated sheet material to the desired shape to form the finished end cone preform of insulating material. Preferably, the metal sheet is a metal foil tape that is laminated to at least one surface of the intumescent or non-intumescent sheet material before the sheet material is cut to the desired dimensions. The metal sheet can also be laminated on both sides of the sheet material. In another aspect, the invention provides a method for forming an end cone insulator preform comprising the steps of providing a flexible and resilient intumescent or intumescent sheet material that is cut to the desired dimensions and initially formed to the desired shape. , partially winding the formed material with a heat shrinkable film, and then exposing the shrinkage film by heat to wrap with sufficient heat to form the finished preform. Surprisingly, applicants have discovered simpler and less time-consuming methods for forming insulating end cone preforms from sheet-like insulating materials, without the need to prepare and handle diluted suspensions of inorganic materials. The preforms resulting from the methods of the invention are flexible and self-sustaining and therefore are easy to use in the manufacture of pollution control devices. One of the advantages of the preforms of the invention is that the preforms of the invention remain relatively flexible, resilient and compressible and maintain the chemical and performance characteristics of the sheet material used to make the preform. As used herein, "self-sustaining" refers to a shaped article which maintains a three-dimensional shape under the force of gravity after it has been shaped. As used herein, an "end cone" preform of insulating material means a self-supporting insulating end cone made of an intumescent or non-intumescent sheet material.

As used herein, an "intumescent" material means a material suitable for use in a contamination control device that contains an intumescent material and that expands or intumesce when exposed to sufficient thermal energy. As used herein, a "non-intumescent" material is a material that is suitable for use in a contamination control device that does not contain an intumescent material.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a cross-sectional view of a catalytic converter having an inner and outer metallic end cone housing with an insulating end cone preform positioned between the end cone housings. Figure 2 shows a sheet material cut by die before being treated. Figure 3 shows a perspective view of an insulating end cone preform of the invention made of the die cut material shown in Figure 2. Figure 4 shows a die cut sheet material before being treated.

Figure 5 shows a perspective view of an insulating end cone preform of the invention made of a die cut sheet material shown in Figure 4. Figure 6 shows a view of another embodiment of the cone preform of the invention. Figure 7 shows a front view of another embodiment of the end cone preform of the invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the figures, Figure 1 shows a contamination control device, and in particular a catalytic converter 10 which comprises a housing 12 with a generally tapered inlet end cone assembly 14 and a cone assembly 16 of exit end. The housing 12, which may also be referred to as a can or a cover, may be made of suitable materials known in the art and is typically made of metal. Preferably, the housing 12 is made of stainless steel. Positioned within the housing 12 is a monolithic catalytic element 18 formed of a monolithic body in the form of a honeycomb of either ceramic or metal material. Surrounding the monolith 12 is a mounting and isolation grid 22.

Referring now to the input end cone assembly 14 and the output end cone assembly 16, it can be seen "that the input end cone assembly 14 and the output end cone assembly 16 comprise each an outer end cone housing 26 and an inner end cone housing 28. An insulating preform liner or end cone 30, which is shown more particularly in FIG. 3, is positioned between the outer end cone housing 28 and the inner end cone housing 26. The inner end cone housing 28 is provided in pollution control devices to retain the insulating end cone 30 in position and prevent the insulating end cone 30 from being damaged by the hot exhaust gases passing through the device of pollution control. The inner and outer end cone housings 26, 28 are typically made of metal and are preferably made of stainless steel or an alloy such as INC0NELMR 600. Figure 2 shows one embodiment of an insulating material 40 which has been die cut to from an intumescent sheet material suitable for use in pollution control devices. The die-cut insulation material 40 is in one piece and has dimensions and shape so that it can be placed between the inner and outer end cone housings 28, 26. The die-cut insulator material 40 is generally in the form of a sheet having major surfaces 42, 44 and a thickness 46. In this embodiment, the die-cut insulating material 40 generally has cuts 48"in diameter. V shape "forming tabs 50. The V-shaped cuts 48 release the sheet surface tension and allow the die cut material 40 to conform to a generally conical shape of insulating material without excessive bending or bending of the insulating material. The shape and size of the V-shaped cuts 48 in the die-cut material are such that the gaps in the insulating material are minimized without undesirable bending or folding of the material when the die-cut material 40 is formed into the desired shape final., the insulating sheet material can be cut into any single piece shape, useful or desired, capable of being shaped into a cone shape with dimensions suitable for the final use. A die cutting machine useful for intumescent and non-intumescent sheet materials is a Rotomatic ™ II die cutter commercially available from Ampa, Inc., Anderson NC. One embodiment of an insulating end cone preform of the invention is shown in Figure 3 as the insulating end cone preform 60. The insulating end cone preform 60 is a finished end cone made of die cut material 40, shown in Figure 2. The insulating end cone preform 60 is characterized in that it is three dimensional, cone shaped and has a front 62 and a rear 64 and is self-supporting although resilient and compressible. When the die cut sheet material 40 is formed in the preform 60, the V-shaped cuts 48 become slots 49. In this embodiment, the sheet material is the INTERAMMR Type 200 intumescent grid (3100 g / m2) and The main surface 44 has been treated and shaped using the retention element in the form of a stiffening solution containing colloidal silica. Figure 4 shows a die-cut sheet material 70 which is used to make a preferred preform 80 of insulating end cone shown in Figure 5. With reference to Figure 4, the sheet material 70 cut by die is one piece and has a crescent shape and has a first end 72 and a second end 74 which are joined together by a shape retaining element in the form of a ribbon 82 to form the preform of the end cone 80 insulator (see Figure 5). The preform of the cone 80 of insulating end is characterized by being self-sustaining in a cone shape and is resilient and compressible. In this preferred embodiment, the die cut sheet material 70 is cut from the intumescent grid INTERAMMR Type 100 (3662 g / m2) which has been laminated with a film 76 of thermoplastic polyester on a surface before being die cut. Thermoplastic films useful for lamination to the surface of intumescent sheet materials include polyester, polyethylene and polypropylene having a thickness from about 0.01 mm to about 0.3 mm. A commercially available preferred film is 3M Tape # 356, from Minnesota Mining and Manufacturing Company, St. Paul, MN. Any tape that adheres sufficiently for substantially intumescent or non-intumescent inorganic sheet materials and / or thermoplastic films used for lamination to the sheet material can be used as a shape retention element for this embodiment. Such useful tapes include masking tapes, cloth tapes, surgical tapes and plastic film tapes, such as a polyester film tape, commercially available as 3M Tape # 356, from Minnesota Mining and Manufacturing Company. An insulating end cone preform is manufactured by placing the ends 72, 74 together to form a cone and then joining the ends together with an adhesive tape. Another embodiment of an insulating end cone preform is shown in FIG. 6 as the preform of the insulating end cone 90. The end cone 90 comprises a cone-shaped intumescent sheet material 91, in the shape of a cone having a plurality of slots 49 and a configuration-retaining element "3" in the form of a metal foil ribbon 92 laminated to the interior or front surface 94. In Figure 7 another embodiment of an insulating end cone preform of the invention is shown, such as a cone preform 100 of insulating end. The end cone 100 comprises a cone-shaped intumescent sheet material 91, in the shape of a cone having a plurality of slots 49 and a configuration retaining element in the form of a heat-shrinkable film 102., applied on an upper portion of the front surface 104 and the rear surface 106 of the sheet material in cone configuration. The die-cut sheet materials used to form the cone configurations can be made of any flexible and resilient insulating sheet material suitable for use in pollution control devices. The material can be intumescent or non-intumescent, and preferably is intumescent. An intumescent sheet material useful for making the die-cut insulating material 40, 60 comprises a flexible and resilient intumescent sheet constituted from about 20 to 65 percent dry weight of unexpanded vermiculite flakes, such scales are not treated or treated when subjected to ion exchange with an ammonium compound such as diacid ammonium phosphate, ammonium carbonate, ammonium chloride, or other suitable ammonium compound, as described in U.S. Pat. No, 4,305,992 (Langer et al.); from about 10 percent to 50 percent dry weight of inorganic fibrous material including aluminosilicate fibers (commercially available under the trademarks FIBERFRAXMR from Unifrax Co., Niagara Falls, NY, and CERAFIBERHR from Thermal Ceramics, Augusta, GA), glass fibers, zirconium-silica and crystalline alumina flakes; from about 3 to 25 percent by dry weight of organic binder including those in the form of latex, for example, natural rubber latex, styrene-butadiene latex, butadiene and acrylonitrile latex, acrylate latex or methacrylate polymers and copolymers and the like; and up to about 40 percent dry weight of inorganic fillers including expanded vermiculite, glass hollow microspheres and ventonite. A preferred intumescent sheet material comprises about 45 to about 62 percent dry weight of unexpanded vermiculite flakes, about 27 to about 45 percent dry weight of inorganic fibrous material and about 3 to about 10 percent organic binder in latex form. Examples of other useful sheet materials and methods for making the sheet materials include those described in US Pat. 5,523,059 (Langer).

In addition, examples of intumescent sheet materials and methods for making such sheet materials include those described in US Patents. Nos. 3,916,057 (Hatch et al.), 4,305,992 (Langer et al.), 4,385,135, (Langer et al.), 5,254,410 (Langer et al.), 4,865,818 (Merry et al.), 5,151,253 (Merry et al.) , and 5, 290, 522 (Rogers et al.). Commercially available, preferred intumescent sheets and grids include those sold under the trade name INTERAMMR by Minnesota Mining and Manufacturing Co. , from St. Paul, MN Intumescent sheet materials are manufactured using well-known papermaking techniques. Mounting grids typically vary in thickness from 0.5 to 10 mm. Other useful intumescent materials include expandable graphite, expandable sodium silicate granules and partially dehydrated vermiculite, as described in US Pat. No. 5,254,410 (Langer et al.). An example of the shape retention element is an organic binder. Thermoplastic organic binders include emulsions of organic polymers and elastomers in the form of latexes such as natural rubber latex, styrene-butadiene latex, butadiene and acrylonitrile latex and polymer latexes and acrylate and methacrylate polymers. The thermoplastic organic binders include polymers and polymer resins such as natural rubber, styrene-butadiene rubber and other elastomeric polymer resins. Acrylic latex and polyvinyl acetate are the preferred thermoplastic organic binders. Other thermoplastic materials useful for use as organic binders include polypropylene, polyvinyl alcohol, polyvinyl chloride and polystyrene. The thermosettable materials useful for use as organic binders include epoxy and phenolic materials. The organic binder may also include blends of two or more thermoplastic and / or thermoset materials. Useful mixtures include a polymer emulsion combined with a resin or thermoplastic material and a polymer emulsion combined with a resin or thermosetting material. Examples of commercially available preferred organic binders include RH0PLEXMR HA-8 (an aqueous acrylic emulsion with 45.5 weight percent solids) from Rohm & Haas, Philadelphia, PA and AIRFLEXMR 600BP (an aqueous polyvinyl acetate emulsion with 55 percent solids) from Air Products, Allentown PA. Inorganic fillers include expanded vermiculite, hollow glass microspheres and bentonite. The non-intumescent insulating sheet materials useful for forming the preform of insulating end cones of the invention generally comprise inorganic fibers and an organic binder. Generally, useful non-intumescent sheet materials comprise from about 60 to about 98 weight percent dry weight of inorganic fiber and from about 2 to about 25 weight percent dry organic binder. A preferred non-intumescent sheet material comprises about 90 percent inorganic fiber and about 10 percent organic binder. The non-intumescent material may also contain inorganic or filler particles and one or more inorganic binders. The non-intumescent insulating material preferably is in the form of a sheet having a thickness from about 0.5 to about 15 mm. Ceramic fibers essentially free of pellets useful for shaping non-intumescent insulating sheet materials include alumina-boria-silica fibers, alumina-silica fibers, alumina fibers-phosphorus pentoxide, zirconia-silica fibers, zirconia fibers- alumina and alumina fibers. The "essentially pellet-free" or "pellet-free" fibers are fibers containing less than 5 percent by weight, and preferably less than 1 percent by weight pellets or non-fibrous particulate material, and fibers which are therefore less 95 percent shot free, and preferably 99 percent shot free. Commercially useful fibers available include those under the commercial brands FIBERMAX ™, available from Unifrax, SAFFILM® LD, available from ICI Chemicals &; Polymers, ALCEN "R alumina fibers, available from Denka and MAFTECH fibers, available from Mitsubishi The fibers are typically formed by blowing or spinning using methods known in the industry Preferably, the fibers are formed by spinning a sol gel solution The fibers are formed into a grid or a sheet by various known methods including blowing the fibrous material onto a collection mesh as practiced in the nonwoven industry A preferred non-intumescent inorganic fiber is a polycrystalline alumina fiber Available under the trade name SAFFILMR from ICI Chemicals and Polymers, the fiber is chemically resistant and can be used in selected applications up to 1600 ° C. It is produced as a low density sheet which consists of a predominantly two-dimensional random orientation of fiber. which results in a lamella-shaped grid.The blade is essentially free of granall a with a uniform fiber structure. The lamellar nature of the low density grid makes it necessary to introduce a means to avoid delamination during handling and assembly in the contamination control device. That is, the low density alumina fiber sheet is preferably physically constrained or compressed during handling and assembly. When compressed to a mounting density of approximately 0.05 to 0.60 grams per cubic centimeter, these materials have a unique ability to repeatedly experience a reduction in their thickness while they are hot and expand back to substantially their original thicknesses when they are cooled, so that maintain their structural integrity. Since the preferred fiber material for the non-intumescent preform of the insulating end cones 60 is generally available in the density range of 0.05 to 0.30 grams per cubic centimeter, they should be compressed by a factor of 10 when used as materials. insulators within the end cone housings 28, 26. The sheets of the non-intumescent insulating material are generally compressed and retained in a compressed state to facilitate the handling and cutting of the material. The non-intumescent insulating sheet material can be physically compressed in various ways, including the use of resin bonding, or needle punching. Bonding with resin is carried out by saturating a non-intumescent material with organic binders which burn in the presence of heat generated from a hot exhaust gas. Organic materials are removed by burning when exposed to heat generated by hot exhaust gases.

Preferred commercially available non-intumescent sheet materials are SAFFIL ™ LD alumina fiber sheets (from ICI Chemicals and Polymers, Cheshire, England) and FIBERFRAX ™ 550K fiber sheet (from Unifrax, Niagara Falls, NY). Organic binders and organic fibers that are useful in non-intumescent sheet materials include those described above for intumescent sheet materials. The intumescent and non-intumescent sheet materials are useful for the present invention and are manufactured by the well known wet stratification methods including methods used for papermaking. A method for making the finished preforms of the invention from a flexible and resilient intumescent or non-intumescent sheet material includes the step of treating at least one of the main surfaces of the intumescent or non-intumescent sheet material. The surface treatment is applied to at least one surface of the sheet material to add sufficient rigidity to the material so that, after the material is shaped into the configuration of an end cone, the end cone preform will be self-sustaining but it will not be too rigid so that it is susceptible to fractures or ruptures during handling for its intended use. Useful surface treatments include applying a configuration retaining element in the form of a stiffening solution to at least one surface of the sheet material. A stiffening solution is a solution which, when applied to the surface of a sheet material and then dried, provides rigidity or rigidifies the surface to which the solution is applied. The solutions can be applied to the surfaces of the intumescent or non-intumescent sheet material by means of a brush or a sprinkler. Useful rigidifying solutions include saturated solutions of colloidal silica, colloidal alumina, silicon carbide, magnesium phosphate, vermiculite emulsions, clay emulsions and monoaluminum phosphate. Commercially available stiffening solutions useful include a suspension of magnesium phosphate (100% solids from ZYP Coatings, Inc., Oak Ridge, TN), Nalco 2327 colloidal silica (50% solids from Nalco Chemical Company, Naperville, IL), and a solution with 50% solids of monoaluminum phosphates (Technical Grade, from Rhone-Poulenc Basic Chemical Co., France). The preferred rigidifying solutions are solutions of colloidal alumina and colloidal silica. Preferably, only one of the surfaces of the sheet material is treated with the stiffening solution. When used, the treated surfaces of the preforms of the invention are adjacent to the outer surface of the inner end of the cone housing.

Generally, the amount of stiffening solution applied to the surface of the intumescent or non-intumescent sheet material may vary depending on the desired characteristics of the final product. However, the treatment must be in sufficient quantity to provide a self-sustaining article. The treatment must also not be in an amount so that it results in a finished part that is brittle and that breaks easily during handling for its intended use. Typically, the amounts of solids of a stiffening solution (percent by dry weight) that are added to a surface of a die cut sheet material is equal to about 10 percent of the dry weight of the die cut part. Once the sheet material is treated with a stiffening solution, the sheet material is formed into the desired configuration, preferably to color the treated sheet material between inner and outer metallic cone cone housings, holding the housings together, placing the assembly in an oven to dry the sheet material, to form the preform of insulating end cones, remove the oven assembly, allow the assembly to cool to room temperature and then remove the insulating end cone preform from the metal housings. Of course, the treated sheet materials can also be formed using any suitable mold having the desired finished article configuration. Another method for treating at least one of the surfaces of the sheet material used to make the preform of the insulating end cones of the invention is to apply a configuration retaining element in the form of a thin layer of metal sheet to the surface of the sheet material. The sheet metal layer can be any metal that can be formed into a three dimensional article for use in a contamination control device. The metal layer can be applied to the surface of the sheet material by means of an adhesive. The metal layer preferably has a thickness from about 0.076 mm (0.0030 inches) to about 0.254 mm (0.0100 inches). A preferred metal is aluminum and the aluminum layer is preferably applied to the surface of the sheet material by means of an aluminum tape such as T-49 Foil Tape (from Minnesota Mining and Manufacturing Company, St. Paul, MN). When used, the metal layer is preferably placed on one or both surfaces of the sheet material before cutting the material to the desired shape and dimension. Another method for treating at least one surface of the sheet material used to make the preform of the insulating end cones of the invention is to apply a configuration retaining element in the form of a layer of heat-shrinkable film to the surface of the material of sheet. A heat-shrinkable film can be applied on one or both of the entire surface of the sheet material and is preferably applied on a portion of the surfaces of the sheet material. Examples of useful heat shrinkable films include polyolefins including polyesters such as polyester film tape SC0TCHPAKMR Type 115 (from Minnesota Mining and Manufacturing Company, St. Paul, MN). In use, the heat-shrinkable film is applied to one or both surfaces of a sheet material using an adhesive or tape, or other bonding means and the sheet material is die cut to the desired shape and dimensions. The sheet-cut and film-coated material is placed around the outer surface of the above metal end cone housing and heat is applied to the film until the film shrinks to form a self-sustaining end cone. The required thermal energy or heat can be applied by means of a heat gun or by a convection oven and the like, and is preferably applied by means of a heat gun. Alternatively, the die-cut sheet material is cut to the desired shape and dimensions, placed on the inner metal end cone housing, and a strip of heat-shrinkable film is wrapped around the edge of the sheet material. the larger circumference, that is, the upper part or the tongue portion of the end cone, and then sufficient heat is applied to shrink the film to form a self-sustaining end cone preform. A preferred heat shrinkable film material is polyester and the heat shrinkable film is preferably applied over the top of the tongue portion of the cut sheet material. Another method for manufacturing the insulating cone end preform of the invention comprises the steps of providing intumescent or non-intumescent materials containing a configuration retaining element in the form of an organic binder comprising a thermoplastic and / or thermoset polymeric material, the sheet material is cut into the desired configuration, the cut sheet material is formed into the desired three-dimensional configuration, and then the intumescent or non-intumescent sheet formed is heated to a sufficient temperature for a sufficient time so that it partially melts or melts and / or cures the organic binder polymeric and causes it to merge to form a three-dimensional and self-sustaining preform of insulating end cone. In the case of a thermoplastic polymer material, the finished end-cone preform is formed and the formed sheet material is cooled. The cut sheet material can be formed by placing the sheet material in a mold having the desired configuration and dimensions and then heating the mold containing the cut sheet material as described above. The amount of the thermoplastic and / or thermosetting polymer material contained within the intumescent or non-intumescent sheet material should be sufficient to form a self-sustaining article from a sheet material. The thermoplastic and / or thermosetting resin contained within the sheet material should not be present in an amount that provides a preform article that undergoes undesirable fracture or rupture during handling for its intended use. Another method for making an end cone preform of the invention comprises the steps of providing an intumescent or non-intumescent sheet material containing a configuration retaining element in the form of an organic binder comprising an aqueous polymer emulsion, for example , a polymer or elastomer in the form of a latex, the sheet material is cut into the desired configuration and dimensions, the cut sheet material is placed in a mold having the dimensions to make the desired finished article, the sheet material is saturated molded with water, and then the sheet material contained within the mold is heated until the water evaporates to form a finished preform article. Alternatively, the molded sheet material can be saturated by applying steam to the sheet material within the mold and then allowing the sheet material inside the mold to dry at room temperature to form the finished preform article. The typical water content of the intumescent or non-intumescent sheet material treated during the forming step varies from about 5 to about 55 weight percent of the sheet material. The intumescent or non-intumescent sheet materials used to form the articles of the invention may also contain one or more organic fibers as configuration retaining elements, in addition to the organic binders described above. When used, the preform of the insulating end cones of the invention are placed inside the inner and outer cone housings, and the housings are welded to form a conical entrance or an outlet for a contamination control device. The conical inlet or outlet is then welded to the metal housing of the contamination control device. The insulating end cones are useful for suppressing noise and vibration in a pollution control device and also for providing thermal insulation of the exhaust heat.

Examples Test methods Hardness test The hardness of the treated surfaces of the finished preform of the end cone insulation liners is determined, using a Shore Durometer ™ instrument for type A hardness determination.

Resilience test method This test is used to measure the amount of resilience of a preform article as a function of the height contained in the preform article after a mass is applied. An end cone preform is placed on a level surface with the larger diameter opening facing down (inverted cone). A sheet of rigid cardboard is placed on the opposite surface. A weight of 20 grams is placed on the cardboard and centered on the end cone, and the height of the cardboard sheet is recorded as the "initial height". The weight of 20 g is removed, and weights of 200 g and 50 g are placed on the cardboard as in the above, and the height of the cardboard sheet is recorded as "final height". Resilience is calculated using the following formula: resilience = (final height / initial height) X 100%. Each of the samples tested should have substantially the same dimensions. Generally, the insulating end cone preforms of the invention have a resilience value of from about 35 to about 97 percent, preferably from about 50 to about 97 percent, and much more preferably from about 75 to about 97 percent.

Test method to determine variation in thickness and density This method is used to determine the variation in the thickness and density of the shaped articles. At least 12 pieces cut by die must be removed from each sample. The pieces cut by die are taken from the edges and the middle portions of each sample. The die is a circular punch that has a diameter of 11 mm. A pressure of approximately 93.6 kPa (13.6 psi) is exerted on each die cut piece of each sample and then each sample is measured to determine the thickness to the nearest 0.003 cm. These measurements can be made using a dial gauge available from Federal, Providence, Rl. each piece cut by die is weighted to 0.01 g nearest and weights are recorded in grams. The weight per unit area (g / m2) is calculated using the following formula: weight per unit area = (weight (g)) / ((121 mm2 x pi) / 4, 000, 000). The thickness values per unit area are averaged, and three standard deviations are calculated. Generally, the preform of insulating end cones of the invention have variability in thickness (3 standard deviations) of less than 50 percent, preferably less than 30 percent and more preferably less than 20%.

Example l A sheet of intumescent sheet material (INTERAMMR Type 200 grid (3100 g / m2 available from Minnesota Mining and Manufacturing Company, St. Paul, MN) is cut with a die using a die cutter (Rotomatic ™ II, from Ampak, Inc. , Anderson, SC) to form a die cut portion similar to that shown in Figure 2, so that it can be adapted to the geometry of an outer metal conical housing.The die cut part has overall dimensions of 144 mm per 155 mm and weighs approximately 48.4 g.The part is treated on the entire surface on one side with a colloidal silica solution NalcoMR 2327, from Nalco Chemical Company, Naperville, IL) with a paint brush.

The coated part is placed inside an outer metal cone housing similar to that shown in Figure 1 (female portion) with the coated surface facing up. The coated part is pressed into the shape of the outer cone housing with an inner cond housing (male portion). The inner cone housing is removed, the part formed inside the outer cone housing is placed inside a laboratory oven with forced air (Blue M 0V-560A-2, from Blue Electric Company, Blue Island, IL) and dried for about 1 hour at a temperature of 110 ° C. After drying, the shaped preform is removed from the outer cone housing, allowed to cool and weighed. The finished preform has a weight of 52.7 g. The dry preform insulation material is self-sustaining and keeps its shape formed during handling. The uncoated surface of the preform is soft and compressible and has a measured hardness value of approximately 25 when measured using a Durometer ™ Hardness Tester and the method described above. The coated surface of the preform has a measured hardness of approximately 40. When the preform is placed on the outer and inner metal cones housings, the preform remains flexible and conformable and can be easily placed in the housings.

Cl Example The procedure used in Example 1 is repeated to form a finished preform except that the die cut part is saturated with colloidal silica by immersing the part in a container containing a colloidal silica solution. After drying, the coated preform has a weight of 77 g. The finished preform is self-sustaining and feels very rigid. The measured hardness value of both surfaces varies from 70 to 80. When the preform is placed inside the inner and outer housings, one of the tongue portions of a part breaks.

Examples 2-3 A sheet of intumescent grid material (INTERAMHR Type 100, 3662 g / m2, from Minnesota Mining and Manufacturing Company) and a sheet of non-intumescent grid material (fiber sheet FIBERFRAXMR 550K from Unifrax, Niagara Falls, NY) is cut with die as described in Example 1 to form Examples 2 and 3 cut with a die. The composition of the sheet of intumescent material of approximately (percent by dry weight) from 42.5 to approximately 62.5 percent unexpanded vermiculite, 27 to 45 percent inorganic fiber, 3 to 10 percent organic latex binder. The composition of the non-intumescent sheet material is approximately 90 percent inorganic fiber and 10 percent organic latex binder. The samples are moistened in tap water by immersion under flowing running water, and then each of the saturated die cut materials is placed between outer and inner end cone housings similar to those described in Example 1 above. The inner and outer end cone housings are held together and then placed in an oven at a temperature of 100 ° C for about 60 minutes until the water evaporates. The attached end cone housings containing the die-cut materials are removed from the furnace, allowed to cool to room temperature and the intumescent and non-intumescent shaped preforms are removed. Insulating materials of intumescent and non-intumescent preform are flexible and self-sustaining and are compressible and can be handled without fracture or rupture.

Examples 4-5 A strip of 4 mm thick aluminum foil (T-49 aluminum tape, from Minnesota Mining and Manufacturing Company, St. Paul, MN) is laminated to a sample of intumescent sheet material (INTERAMMR Type 100, 3662 g / m2, from Minnesota Mining and Manufacturing Company) which has dimensions of approximately 35 cm by 35 cm so as to cover the entire surface of the intumescent sheet material. The sheet-covered sheet material is then die cut as in Example 2. The die-cut and sheet-coated part is then formed on the outer surface of an inner metal cone housing with the side of the sheet adjacent to the sheet. exterior surface of the outer end cone housing. The outer end cone cover is then placed on the outside of the insulation material and properly placed inside a finished end cone. The outer end cone distance is removed, and the shaped preform is removed. The sheet-coated preform formed of Example 4 is flexible and self-supporting. The procedure of Example 4 is repeated, except that both sides of the intumescent sheet material are covered with the sheet tape to form the preform of Example 5. The preform of Example 5 is flexible and self-supporting.

Example 6 An intumescent sheet material is die cut as described in Example 2. The die cut material is then formed on the inner end cone housing of Example 2 and a heat shrinkable polyester film, SCOTCHPAKMR Type 115 tape, is rolled around the top of the open edge of the intumescent material cut by die so that it extends about 20 mm beyond the lip or edge of the die-cut material. The heat-shrinkable film is approximately 33 mm wide and approximately 300 mm long. Heat is applied to the film by means of a 1440-watt heat gun for approximately 30 seconds until the wrap shrinks around the cut material. The shaped preform is removed from the inner end cone housing and is flexible and self-supporting. An advantage of this method for forming a preform of end cone insulating material is that a relatively small amount of shrink wrap film is required to form the preform of the invention.

Example 7 An intumescent sheet material cut by die as described in Example 2, is coated on one side with the stiffener solution described below. The stiffening solution is applied to the die-cut material using a small brush until the entire surface of the material appears damp. The stiffening solution is 5: 1 de-3ß-magnesium phosphate cement in deionized water (cement ZYPMR RS-100, from ZYP Coatings Inc., Oak Ridge, TN). The coated sample is placed between the inner and outer end cone housings as described in Example 2. The clamped end cone housing containing the coated sample is placed in a 100 CC oven for approximately 60 minutes until the The coating is dried to form the preform end cone article. The resulting preform end cone is flexible and self-sustaining and can be operated without undesirable fractures or breaks.

Example 8 One sheet of intumescent sheet material (INTERAMR Type 100, 3662 g / m2, from Minnesota Mining and Manufacturing Company) is laminated to a surface with a polyester film tape (3M Tape # 356) and then die cut in the shape, as shown in figure 4. The ends are joined so that the cut sheet material is in the form of a cone and then the ends are adhered together with a piece of polyester film tape to form a preform end of the insulating end cone shown in figure 5.

Examples 9-12 and Comparative examples C2-C4 Examples 8-13 described below are tested for resilience using the resilience test method described above. Example 9 is the preform of Example 1. Example 10 is the preform of Example 2. Example 11 is the preform of Example 4. Example 12 is the preform of Example 6. Example 13 is the preform of Example 8. Comparative examples C2, C3 and C4 are also tested using the above method. C2 is the comparative preform Cl. C3 is an end cone immersion molded of an insulating coating that is made using a mold that has the same shape as the mold used in the Example 1. The composition of C3 is about 7.35 percent dry weight of starch binder and about 92. 65 percent dry weight of refractory ceramic fiber. C4 is an immersion-molded insulated coating manufactured as described in C3 above, having a composition of approximately 14 percent by dry weight of binder starch and 86 percent by weight of crushed intumescent sheet material (mounting material INTERAMMR XD, from Minnesota Mining and Manufacturing), the shredded intumescent sheet material has a dry weight composition of approximately 45-62.5% unexpanded vermiculite, 27.5-45% ceramic fiber and 3-10% organic binder. Immersion-molded end cone liners are made by making dilute aqueous suspensions, placing a permeable mold into each of the suspensions and removing the water using gravity and / or vacuum, and then drying the end cone liners formed in mold. The results are shown in Table 1 below.

Table 1 - 3d - The results show that the preform of the insulating end cones of the invention are more compressible than end cones preforms having similar compositions that are saturated with a rigidifying solution and that are molded by immersion. Therefore, the preforms of the invention are easier to handle in a manufacturing process and are less susceptible to breakage and splashing than end cone coatings molded by saturation or immersion.

Example 14 and Comparative Examples C5 and C6 The intumescent sheet material used to make the insulating end cone preform of Example 10 (Example 14 below) and Comparative Examples C3 (C5 below) and C4 (C6 below) are tested to determine their thickness and density variability using the method described before. The results are shown in Table 2 below.

Table 2 The results show that the intumescent pre-cones of insulating end cones of the invention have a more uniform thickness than immersion-molded end cone liners of the same dimensions and a more uniform density (weight per unit area) than a waterborne coating. intumescent tip cone molded by immersion. Additionally, the insulating end cone preform of the invention maintains the resilience and compressibility of the intumescent sheet material while the dip-molded end cone coatings are relatively hard and brittle. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers.

Claims (20)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. An insulating end cone preform, suitable for forming the end cone of a contamination control device, the preform is characterized in that it comprises: a cone-shaped intumescent sheet material having a plurality of grooves that allow the material of blade acquires cone configuration, - and a configuration retaining element in intimate contact with the intumescent sheet material, the shape retaining element allows the intumescent sheet material to maintain a cone configuration.

2. The preform of the insulating end cone, according to claim 1, characterized in that the configuration retaining element is an organic binder.

3. The preform of the insulating end cone, according to claim 2, characterized in that the organic binder is a polymer emulsion.

4. The preform of the insulating end cone, according to claim 1, characterized in that the configuration retaining element is a metal sheet.

5. The preform according to claim 1, characterized in that the configuration retaining element is a heat-shrinkable film.

6. The preform according to claim 2, characterized in that the organic binder is a thermoplastic material.

The preform of the insulating end cone, according to claim 2, characterized in that the organic binder comprises a thermosetting material.

8. The preform of the insulating end cone, according to claim 1, characterized in that the configuration retaining element is a rigidifying solution.

The preform of the insulating end cone, according to claim 8, characterized in that the stiffening solution is selected from the group consisting of aqueous colloidal silica, aqueous colloidal alumina, monoaluminium phosphate, magnesium phosphate, vermiculite emulsions and emulsions of clay.

10. An insulating end cone preform, suitable for forming the end cone of a contamination control device, the preform is characterized in that it comprises: a cone-shaped intumescent sheet material "having a first end and a second extreme; and a configuration retaining element in intimate contact with the intumescent sheet material, the configuration retaining element allows the intumescent sheet material to maintain a cone configuration.

The preform of the insulating end cone, according to claim 10, characterized in that the configuration retaining element is a strip joining the first end and the second end together.

The preform of the insulating end cone, according to claim 11, characterized in that the configuration retaining element further comprises a thermoplastic film laminated to a surface of the sheet material, wherein the tape adheres to the thermoplastic film.

13. A pollution control device, characterized in that it comprises: (a) a metal housing; (b) a monolithic catalytic element, - (c) an inlet and an outlet of the metal end cone assembly for joining the exhaust pipes of the metal housing, each cone assembly comprises an inner end cone housing and an inner end housing. outer end cone; and (d) an insulating end cone preform of any one of claims 1 to 12, positioned between the inner end cone housings.

A method for making an insulating end cone preform, according to claim 1 or claim 10, characterized by "being used in a pollution control device, comprising the steps of: (a) providing a intumescent or non-intumescent insulating material in the form of a sheet having first and second main surfaces and having the desired dimensions for the finished preform of the insulating end cone, the insulating material contains an organic binder comprising a polymeric emulsion, - ( b) treat the insulating material with water or steam; (c) forming the insulating material treated in the desired configuration for the finished preform of the insulating end cone; and (d) drying the shaped insulating material to form a finished preform of insulating end cone.

15. The method according to claim 14, characterized in that the sheet material is intumescent.

16. The method according to claim 15, characterized in that the intumescent sheet material comprises from about 20 to 65 percent by dry weight of an intumescent material, from about 10 percent to 50 percent by dry weight of inorganic fibrous material, from about 3 to 25 percent by dry weight of organic binder, and up to about 40 percent dry weight of inorganic filler.

The method according to claim 14, characterized in that it further comprises the step of forming the treated insulating material in a desired configuration by placing the treated insulating material in a mold having the dimensions of an end cone assembly of a device of pollution control.

18. A method for making an insulating end cone preform, according to claim 1 or claim 10, for use in a contamination control device, the method is characterized in that it comprises the steps of: (a) providing a intumescent or non-intumescent insulating material in the form of a sheet having first and second main surfaces and having the desired dimensions for the finished preform of the insulating end cone; (b) treating a surface of the insulating material with a stiffening solution that is selected from the group consisting of aqueous colloidal silica, aqueous colloidal alumina, monoaluminium phosphate, magnesium phosphate, vermiculite emulsions and clay emulsions; (c) forming the insulating material treated in the desired configuration for the finished preform of the insulating end cone; and (d) drying the shaped insulating material to form a finished preform of insulating end cone.

A method for manufacturing an insulating end cone preform, according to claim 1, or claim 10, for use in a pollution control device, characterized in that it comprises the steps of: (a) providing an insulating material intumescent or non-intumescent in the form of a sheet having first and second main surfaces and having the desired dimensions for the finished preform of the insulating end cone; (b) treating a surface of the insulating material by applying a metal foil on a surface of the insulating material; and (c) forming the insulating material treated in the desired configuration to form a finished preform of insulating end cone.

20. A method for producing an insulating end cone preform, according to claim 1, or claim 10, for use in a contamination control device, characterized in that it comprises the steps of: (a) providing an intumescent insulating material or non-intumescent in the form of a sheet having first and second major surfaces and having the desired dimensions for the finished preform of the insulating end cone; and (b) forming the insulating material in the desired configuration for the finished preform of the insulating end cone; (c) treating a surface of the insulating material by applying a heat-shrinkable film on a surface of the insulating material; and (d) heating the shrinkable film by heat to a temperature sufficient to cause the film to shrink to form the finished preform of the insulating end cone.