INTOMESCENT SHEET MATERIAL AND ORGANIC ORTIZING PONTE PASTEFIELD OF THE INVENTIONThe present invention relates to assembly materials for high temperature environments such as catalytic converters and diesel particulate filters.
BACKGROUND OF THE INVENTIONPollution control devices are used in motor vehicles to control air pollution. Currently, two types of devices are in use - catalytic converters and filters or diesel particulate traps. The catalytic converters contain a catalyst, which is typically coated on a monolithic structure in the converter. The catalyst oxidizes carbon monoxide and hydrocarbons, and reduces nitrogen oxides in exhaust gases or exhaust from automobiles in order to control air pollution. Diesel particulate filters or traps are wall flow filters in which the monoliths have honeycomb structuresREF: 26453 of bee and that are made of crystalline porous ceramic materials. In the state of the art for the construction of these devices, each type of device has a metallic housing which is retained within a monolithic structure or element which can be metallic or ceramic, more commonly ceramic. The ceramic monolith generally has very thin walls to provide a large amount of surface area and is brittle and susceptible to breakage. It also has a coefficient of thermal expansion generally an order of magnitude less than the metal (usually stainless steel) of the housing in which it is contained. In order to avoid damage to the ceramic monolith caused by road crash and vibrations, to compensate for the difference in thermal expansion and to prevent the exhaust gases from passing between the monolith and the metal housing, carpet or ceramic paste materials are typically placed between the ceramic monolith and the metal housing. Ceramic carpet materials, ceramic pastes and intumescent sheet materials useful for mounting the monolith in the housing are described, for example, in US Pat. 3,916,057 (Hatch et al.), 4,305,992 (Langer et al.), 4,385,135. { Langer et al.), And GB 1,522,646 (Wood). British patent specification 1,513,808 describes a flexible intumescent sheet with 5 to 20 percent organic binder. The currently available mounting materials typically include a binder, an intumescent agent and fibers. The binders used have been inorganic and include materials such as clay, expanded or treated vermiculite and the like. Small amounts of organic binders such as styrene-butadiene reticles, rubber, acrylics and the like have also been included with inorganic binders to improve the flexibility and elasticity of the stock or sheet material. The organic materials are typically used in amounts of less than 15% by weight because the organic material is burned after the initial heating of the catalytic converter of the diesel filter, and it is generally believed that the burning of the organic binders can result in voids. which can lead to the weakening of the mounting material and a failure to retain the monolith in place. During the first heating cycle the pressure inside the can typically decreases initially due to the burning of the organic binder, dehydration and shrinkage of other binders, before the vermiculite expands. In the past, organic binder concentrations remained below about 15 percent due to concern that the mounting material could fail to retain the monolith in place during the first heating cycle. EP 639 700 (Stroom et al.) Discloses the use of an organic binder system with a mixture of glass and other filler materials to provide an edge protective material which covers at least a side edge portion of a carpet. intumescent assembly to protect the carpet from erosion at high temperatures. The use, the organic binder is burned and the glass particles then act as a high temperature inorganic binder to keep the selected filling materials together and provide a barrier that protects against erosion. The composition is used only as an edge protector and is not suitable for providing primary support to the monolith structure. Although it has its own utility as an edge protector, the compositions described should not be suitable as mounting materials because they contain relatively large amounts of glass. Glass does not exert a holding force at low temperatures of use since the glass is hard, brittle, and is a solid mass below its softening point; The glass can flow at higher temperatures. The combination of glass and organic binder materials can be expanded sufficiently to fill the larger space caused by expansion of the metal housing by heating; however, this expansion may occur only during the first heating cycle. When the glass is again exposed to temperatures above the softening point of the glass, the glass will deform to release tension and stop providing a holding force to hold the monolith in place. Fibers have also been used to improve flexibility and strength and to facilitate the handling of sheet materials made mainly of inorganic materials. For this purpose, metallic mesh materials have been used. Refractory ceramic fibers such as those of alumina silicates are also commonly used because they provide high strength and flexibility needed in sheet materials. However, these materials in conventional formulations can provide unacceptably high canning forces when densities greater than 1.0 g / cc are desired. There has also been difficulty in including a fine particle size or high density filling materials in conventional wet setting formulations with ceramic fibers. It is undesirable to use refractory ceramic fibers having a fiber diameter of less than about 5 microns.
There is an increasing need for high strength materials useful for mounting fragile structures in catalytic converters and diesel particulate filters which do not use refractory ceramic fibers or small diameter ceramic fibers. The present invention provides assembly materials with an organic binder level greater than 20 weight percent. These high levels of organic binder unexpectedly provide assembly materials with highly desirable properties. An interesting property of some embodiments of the invention is that it is possible to wind assembly material around a monolith so that the sheet overlaps itself. Due to the plasticity of the mounting material, an overlay sheet or sheet can still provide a good seal. The currently available mounting mats are too rigid to provide a good seal and the carpet overlaps itself.
BRIEF DESCRIPTION OF THE INVENTIONThe invention provides a catalytic converter or a diesel particulate filter comprising: (a) a housing; (b) a catalytic converter element or a diesel particulate filter element positioned within the housing; and (c) a flexible intumescent sheet material positioned between the catalytic converter element and the housing; wherein the flexible intumescent sheet material comprises 1 to 70 percent by dry weight of at least one unexpanded intumescent material, from more than 20 to 50 percent by dry weight of organic binder, 5 to less than 79 percent by weight dry weight of inorganic binder and 0 to 70 percent dry weight of one or more filler materials. Additional features and advantages of the invention will be set forth in the description that follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objects and other advantages of the invention will be realized and will be obtained by the methods and articles indicated particularly in the written description and claims thereof. It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide a further explanation of the invention as claimed.
TITLE OF THE DIBBONSFigure 1 is a real condition device test graph for Example 2. Figure 2 is a real condition device test graph for Comparative Example Cl. Figure 3 shows the compression test results of the Examples 1, 2, Cl and C2. Figure 4 is a graph of the actual condition device test for Example 4. Figure 5 is a graph of the actual condition device test for Example 5. Figure 6 is a graph of the actual condition device test for Example 6. Figure 7 is a graph of the actual condition device test for Example 7. Figure 8 is a graph of the actual condition device test for Example 8. Figure 9 is a graph of the device test of actual condition for Comparative Example C3. Figure 10 is a graph of the actual condition device test for Comparative Example C4.
Figure 11 is a graph of the actual condition device test for Example 9.pre O.TP CTT T? RTAT_T _? \ P * ™ * TA T * ™ ^ 1 ^The invention provides a mounting material for use in high temperature applications such as catalytic converters, diesel particulate filters and high temperature filters. In particular, the invention provides a mounting material having a high amount of organic binder, that is, more than 20% by weight, used to mount the catalytic converter elements or diesel particulate filter elements. The assembly material comprises from more than 20% to 50% by weight of an organic binder5 to less than 79% by weight of an inorganic binder, 1 to 70% by weight of an intumescent agent, and 0 to 70% of fillers by weight, including fibers, particulates, etc. In a preferred embodiment, the sheet material comprises less than 15 percent by dry weight of glass particles. The fillers are preferably present in an amount of from 5 to 30 weight percent. The mounting materials of the invention can be provided as a paste, a sheet or sheet or a carpet or rug. Each of these forms has different variable requirements and compositions within the scope of the invention and can be used to satisfy these requirements. For example, the paste compositions need suitable rheological properties so that the compositions can be pumped into the space between the monolith and the metal housing during assembly or canning operation as well as flexibility to hold together at temperatures of use. The sheets and carpets require elasticity as well as strength, flexibility and conformability before assembly since the sheets or carpets are formed first, and then wrapped around the monolith. Carpet sheets need sufficient internal strength to hold together as they typically undergo additional processing before assembly, such as die cutting, transport, etc. Additionally, carpets are formed by a wet laying process, also known as a papermaking process, so that in the formation of carpets, carpet compositions, which generally contain a large amount of water, must formulated to drain well during the training process. The carpet compositions should also be formulated to provide a suitable mounting density to provide adequate pressure to retain the monolith in place. Typically, the assembly densities before the mounting range are from about 0.9 grams per cubic centimeter (g / cc) to about 1.2 g / cc. The sheets and carpets can also be provided in a carrier or release liner. Useful carriers include papers such as kraft paper, polyethylene coated kraft papers, waxed paper and the like, and films such as biaxially oriented polyester. Optionally, the carriers can be readapted with a suitable release agent such as commercially available fluorocarbon materials, talcs and the like. Suitable organic binder materials include aqueous polymer emulsions, solvent-based polymer solutions and 100% solid polymers. Aqueous polymer emulsions are organic binder polymers and elastomers in the form of latexes (e.g. natural rubber grids, styrene-butadiene grids, butadiene-acrylonitrile grids, and acrylate-methacrylate polymer and crosslinkers). Polymer solvent-based binders include for example, a polymer such as an acrylic, a polyurethane or an organic polymer based on rubber in an organic solvent such as toluene, methyl ethyl ketone, ethane and mixtures thereof. 100% solid polymers include natural rubber, styrene-butadiene rubber and other elastomers.
Acrylic materials are preferred because of their excellent aging properties, their slow burning wear with respect to the temperature range used and the non-corrosive combustion products. The binder material may include at least one of a tackifying substance, a plasticizer and / or both. Adhesion improving substances, or resins that improve adhesion, can be modified hydrocarbons or rosin esters and typically provide adhesive-like properties to a polymer. Substances that improve adhesion help in the retention of the binder and fillers together. The plasticizers tend to soften a polymer matrix and therefore contribute to the flexibility and molding ability of the sheet materials made of the composition. Rheology modifiers may also be included to provide the desired flow properties. Preferably, the organic binder material includes an aqueous acrylic emulsion. Useful acrylic emulsions include those commercially available under the trade designations "RHOPLEX TR-934" (an aqueous acrylic emulsion with 44.5% solids weight) and "RHOPLEX HA-8" (an acrylic aqueous emulsion of 44.5% acrylic copolymers in weight of solids), by Rohm and Haas of Philadelphia, PA. A preferred acrylic emulsion is commercially available under the trade designation "NEOCRYL XA-2022" (an aqueous dispersion of 60.5% acrylic resin solids) from ICI Resins US of Wilmington, Massachusetts. Useful organic binder materials may comprise from 0 to 80 weight percent plasticizer, 0 to 100 weight percent of substances that improve adhesion, and 0 to 100 weight percent acrylic resin. A preferred organic binder material for a sheet or carpet comprises acrylic resin in the range of from about 25 to about 50 weight percent, plasticizers (for example, such as those commercially available under the trade designation "SANTICIZER 148" (isodecyldiphenyl diphosphate). from Monsanto of St. Louis Missouri) in the range from about 15 to about 35 weight percent, substances that improve adhesion (for example, substances that improve the adhesion of rosins such as those commercially available under the trade designation "SNOWTACK 810A" ( a dispersion of 50% by weight aqueous rosin; melting point of the rosin: 55 ° C, from Eka Nobel, Inc., of Toronto, Canada) in the range from about 25 to about 50 weight percent, based on to the total weight of the resulting dispersion.
These intervals provide a balance between the desired flexibility of the binder material and minimize the amount of organic binders which are removed by burning during heating at the temperatures of use. For an injectable paste, the preferred organic binder comprises a larger amount of acrylic resin. Suitable inorganic binders are known in the art for such use and include water-swellable clays such as montmorillonite (present in major amounts in bentonite, hectorite and saponite) and kaolinite; synthetic mica which can be swollen with water such as tetrasilicic fluorine mica, either in unaltered form swollen with water or after flocculation as the salt exchanged with a divalent or polyvalent cation; expanded vermiculite and delaminated vermiculite; and expanded and milled vermiculite, which can be prepared, for example, by treatment in ball milling or mixing with high shear of unexpanded or expanded vermiculite. Preferred inorganic binders include delaminated expanded vermiculite and ground expanded vermiculite. Also useful are inorganic refractory fibers such as ceramic fibers, metal fibers and other mica-like materials.
Useful fibers include those made of graphite, silica, alumina-silica, calcite-silica, asbestos, glass, metals, such as Inconel and stainless steel and polymeric materials such as rayon and acrylic. Commercially available fibers include aluminosilicate fibers (available, for example under the trade designations "NEXTEL 312 CERAMIC FIBERS", "NEXTEL 440 CERAMIC FIBERS" and "NEXTEL 550 CERAMIC FIBERS" from Minnesota Mining &Manufacturing Company), "FIBERFRAX 7000M" from Carborundum Company of Niagara Falls, New York, "CERAFIBER" from Thermal Ceramics of Augusta, Georgia and stainless steel fibers (available, for example, under the trade designation "BEKI-SHIELD GR90 / C2 / 2" from Bekaert Steel Wire Corp of Atlanta, Georgia). Preferred fibers include glass fibers, metal fibers and polymer fibers. The composition may include up to 15% by weight of glass fibers or particles. Preferably, the glass fibers are used in amounts of less than 5% by weight so that the total glass content, i.e. the total of glass fibers and glass particles in the composition is less than about 15% . Useful types of glass include calcium and borosilicate glass such as calcium and aluminosilicate glass, magnesium and aluminoborosilicate glass and alkaline borosilicate glass. The preferred glasses are alkaline borosilicate glasses and magnesium and aluminosilicate glasses. As used herein, the term "glass" refers to an amorphous inorganic oxide material (i.e., a material having a diffuse X-ray diffraction pattern with no defined lines to indicate the presence of a crystalline phase). Suitable glass fibers have a softening point close to the use temperature. This temperature is typically less than about 900 ° C, preferably less than 850 ° C, and more preferably less than about 800 ° C. The term "softening point" refers to the temperature at which a glass in the form of a fiber of uniform diameter is elongated at a specific rate under its own weight. Suitable glass fibers include those commercially available under the trademark Micro-Strand "Micro-Fibers" from Schuller International, Inc. Useful intumescent materials include unexpanded vermiculite, i.e., vermiculite ore, or intumescent graphite, such as graphite intercalated obtained from Union Carbide Co., Inc. under the trade name UCAR, hydrobiotite and water-swellable synthetic tetrasilicic fluorine type mica described in U.S. Pat. 3,001,571. Preferred intumescent materials include vermiculite ore, unexpanded vermiculite, and intumescent graphite. The choice of intumescent materials can vary based on the desired end use. For higher temperatures, for example greater than about 500 ° C, vermiculite materials are preferred since they begin to expand at about 285 ° C to fill the expansion spaces between the expanded metal housing and the monolith. For use at a lower temperature, for example at about 500 ° C, such as diesel particulate filters, intumescent graphite may be preferred since it begins to expand at about 210 ° C. The sheet-shaped assembly materials of the invention can also be reinforced to improve handling characteristics, improve operation at elevated temperature, or both, by using reinforcing laminate materials such as a mesh material, for example. example, a stainless steel mesh, woven or non-woven fabrics, or thin sheets of metal. A diffusing gauze can be used to reinforce the mounting material; the diffusing gauze is preferably on one side of the sheet so that it is not in direct contact with the catalytic converter element. Useful diffusing gauzes include nonwoven polyethylenes, nylon, polyesters and the like.
Compressed and low density materials can also be used as fillers. The compressible filler materials can be used to reduce the weight of the mounting materials as well as to reduce the compression pressure during the initial heating of the catalytic converter when the intumescent agents expand and the mounting material begins to exert pressure against accommodation. The compressible filler materials would collapse to prevent excessive pressure buildup. Suitable compressible fillers include hollow glass bubbles, non-delaminated and expanded vermiculite, and pearlite. Other suitable fillers include materials that are relatively insoluble in water. Such materials include hydrated metal oxides (for example alumina and sodium silicate), borates (for example boric acid and zinc borate), calcium carbonate, talc, feldspar, silicon carbide and silica sand. Other additives that can be included in an amount suitable for their purpose are defoaming agents, active agents, fungicides and bactericides. The mounting materials of the invention may additionally include a narrow strip of an edge protection material to reduce erosion of the hot gases incident on a catalytic converter. Useful materials for an edge protection strip include wire mesh fabrics as described in U.S. Pat. 5,008,086 (Merry) and the filled glass strip material described in EP 0 639 700 Al (Stroom et al.), Which can also be used. If sheet or carpet mounting materials are sticky due to organic binders, it may be desirable to powder coat the sheets or carpets with talc or finely divided inorganic or organic particles to reduce adhesion. In the practice of the invention, the binder materials, the optional intumescent agent and the optional fibers are mixed together. Optionally, water, dispersants, tackifying substances, plasticizers and surfactants can be added independently to aid in the mixing of the components together and / or to adjust the viscosity of the mixture. The mixing of the ingredients can be carried out by any convenient method including hand stirring or commercially available metal mixers such as Mogul mixer and Ross mixers. The resulting viscous mixture can then be formed into the desired shape suitable for final use. For example, the resulting mixture can be formed or extruded into a sheet or can be molded to a certain shape and dimension. The mixture can be molded around a monolith as described in the co-pending application entitled "METHODS FOR MANUFACTURING A CATALYTIC CONVERTER OR DIESEL PARTICULATE FILTER" (METHODS OF MAKING A CATALYTIC CONVERTER OR DIESEL PARTICULATE FILTER), PCT Application No. Lawyer No.51747PCT7A). The mixture can also be used in paste form, and can be pumped directly into the housing between the monolith and the housing, or it can be pumped into a suitable mold. Optionally, the sheet or molded shape can be dried. The sheets and molded shapes of the invention have been found to have excellent handling properties both in the fresh as well as in the dry state. In alternative formulations, sufficient binders and inorganic fibers can be used to provide compositions that are formed into carpets by a wet laying process. In another aspect, the invention provides a catalytic converter or a particulate diesel filter that it uses in assembly material of the invention. A catalytic converter or diesel particulate filter generally comprises a housing, elements for holding the catalyst or a filter element and a mounting material placed between the structure and the housing to hold the structure in place. The metal housing, which is also known as a can or receptacle, can be manufactured from suitable materials known in the art for such use. Preferably, the housing is made of stainless steel. Suitable catalytic converter elements, also referred to as monoliths, are known in the art and include those made of metal or ceramic. The monoliths or elements are used to hold the catalyst materials for the converter. A useful catalytic converter element is described, for example, in U.S. Pat. RE 27,747 (Johnson). Ceramic catalytic converter elements are commercially available, for example, from Corning Inc., Corning, New York and NKG Insulator Ltd. of Nagoya, Japan. For example, a honeycomb ceramic catalyst support is sold under the trade designation "CELCOR" by Corning Inc., and "HONEYCERAM" by NGK Insulator Ltd. Metal catalytic converter elements are commercially available from Behr GmbH and Co. of Germany. For further details regarding catalytic monoliths, see for example, "Approach systems for packaging design for automotive catalytic converters" (Systems Approach to Packaging Design for Automotive Catalytic, Converters) Stroom et al., Document No. 900500, SAE Series of Technical Documents, 1990; "Thin wall ceramics as supports for monolithic catalysts" (Thin Wall Ceramics as Monolithic Catalyst Support) Howitt, Document 800082, SAE Series of Technical Documents, 1980; and "Flow Effects in Monolithic Honeycomb-shaped Automotive Catalytic Converters" (Flow Effects in Monolithics Honeycomb Automotive Catalytic Converters) Howitt et al., Document No. 740244, SAE Series of Technical Documents, 1974. Coated catalyst materials on the elements of the catalytic converter include those known in the art (for example metals such as ruthenium, osmium, rhodium, iridium, nickel, palladium and platinum, and metal oxides such as vanadium pentoxide, and titanium dioxide). For further details regarding catalytic coatings, see, for example, U.S. Pat. 3,441,381 (Keith et al.). Conventional monolithic particulate filter elements are typically wall flow filters constituted of porous, honeycomb-like, crystalline ceramic material (e.g. cordierite). The alternating cells of the honeycomb structure are typically plugged so that the exit gas enters a cell and is forced through the porous wall of a cell and out of the structure through other cells. The size of the diesel particulate filter element depends on the particular application needs. Useful diesel particulate filter elements are commercially available, for example, from Corning Inc. of Corning, New York and NGK Insulator Ltd. of Nagoya, Japan. Useful diesel particulate filter elements are discussed in "Cellular Ceramic Diesel Particulate Filter", Howitt et al., Document No. 810114, SAE Series of Technical Documents, 1981. In use, assembly materials of the invention are placed between the monolith and the housing in a similar manner either for a catalytic converter or for a diesel particulate filter. This can be done by wrapping the monolith with a sheet of mounting material, and inserting the monolith wrapped in the housing, pumping the mounting material into a housing containing the monolith, coating the mounting material around the monolith or molding the material assembly around the monolith and insert the composite material into the housing. When the housing containing the assembled monolith is heated for the first time, the compressive forces increase as the intumescent agents expand. The state of the art with respect to the assembly materials are elastic in nature and are based on elasticity in order to retain the monolith in place. However, as the pressure inside the housing increases, particularly when the spaces between the housing and the monolith are small, there are compressive forces that exceed the strength of the monolith and compress it. The mounting materials of the invention show plastic deformation in the dry state during heating, the mounting materials will exert compressive forces only to the point of plastic softening, beyond which the forces do not increase against the monolith. In addition, after the burning out of the organic binders, it has been found that the mounting materials have excellent erosion resistance. The objects and advantages of this invention will be further illustrated by the following examples, but the particular materials and amounts thereof mentioned in these examples, as well as other conditions and details should not be considered as limiting this invention. All parts and percentages are by weight unless stated otherwise.
Test d StirringThe hot agitation test is used to evaluate the mounting material for a catalytic converter by subjecting a catalytic converter with the assembly to vibration and hot exhaust gases from a gasoline engine. A test assembly is prepared by cutting a strip of mounting material measuring 2.54 cm wide by the length of the circumference of the monolith used for the test and winding it around the middle part of an oval ceramic monolith (available from Maramont, Loudon , Tennessee) which measures 14.6 cm (5.75 inches) by 8.1 cm (3-3 / 16 inches) by 8.9 cm (3-1 / 2 inches) in length. The sheet and the monolith are then placed in a half of a design catalytic converter housing of two clam shell bricks which have been cut in half to accommodate a single brick or monolith for testing. The dimensions of the approximate cutting housing are 17.15 cm (6.75 inches) long with an oval cross section of 15.2 cm (6 inches) by 8.9 cm (3-1 / 2 inches) with a wall thickness of 1.40 mm (0.055) inches). The two halves of the clam shell are clamped together and welded together to seal the seam to form the assembly. The flange mount is then fixed to the tapered end of the converter and welded in place. The catalytic converter, with the ceramic monolith mounted securely therein, is attached to the top of a solid device of a stirring table (model TC 208 of an electrolytic stirring table of Unholtz-Dickie Corp., Wallingford, Connecticut). The converter is then connected via a flexible coupling to the output system of a 7.5-liter V-8 petrol driven internal combustion engine from Ford Motor Co. The converter is tested using an exhaust gas temperature in the 900 ° C inlet at an engine speed of 2200 revolutions per minute with a load of 30.4 kg-meter using an Eddy Eaton 8121 current dynamometer while stirring the converter at a frequency of 100 Hz and an acceleration of 30 g of the table of agitation. The converter is stirred for 100 hours or until it fails and then it is separated and the mounting material is examined visually. The visual inspection determines if the monolith has fractured or if the monolith has moved inside the housing.
Device test ^ TOÜff ffn EIHll (R FTIThe RCFT is a test used to measure the pressure exerted by the mounting material under conditions representative of the actual conditions found in a catalytic converter during normal use. Square samples measuring 44.5 by 44.5 cm from the mounting material are cut and placed between two metal plates of 50.8 mm by 50.8 mm, attached to a load frame. The plates are controlled independently, for heating and heated to two different temperatures to simulate metal housing and monolith temperatures. Simultaneously, the space between the plates is increased by a value calculated from the temperature and the coefficients of thermal expansion of a typical catalytic converter. The temperatures of the plates and the change of space are presented in table 1 below. The force exerted by the mounting material is measured by a Sintech ID computer-controlled load frame with an extensometer (MTS Systems Corp., Research Triangle Park, North Carolina). The results are shown in a graph of pressure vs. temperature and distance of space.
Table 1Compression TestThis test is an indication of how much pressure is generated by the mounting materials during the canning or assembly of the monolith in the housing. Excessive pressures are undesirable because high pressures can cause damage to the monolith during the canning process. Cut a 5.08 cm diameter disc from the mounting material and mount it between two 10.5 cm diameter movable plates in a tension tester (MTS model 812.21 hydraulic load frame with the controller model 442, model 413 control panel and model 430 digital indicator available from MTS Systems Corp. Research Triangle Park, North Carolina). The plates close at a speed of 2.54 mm (0.1 inches) per minute to a space of 2.29 cm (0.09 inches). The resulting pressure build-up is plotted on a graph and graph pressure vs. space distance.
PT - "* ^ ti r _ rffB_i" ^ Cyclical CalfixitaflaThis test is a measure of the durability of an assembly amount when subjected to cyclic mechanical compression at an elevated temperature. The test is carried out in a vertical tubular furnace of the compression test apparatus described above with a digital generator 410 (available from MTS Systems Corp.). A 5.08 cm disc is mounted between quartz plates in the oven which are attached to the outer load frame of the oven. The disk is compressed to a fixed open space of 3.34 mm (0.1315 inches) between the quartz plates, and the furnace is then heated to 650 ° C. The space is then closed to a distance of 2.96 mm (0.1165 inches) and then immediately opened to the open space. Each cycle requires 30 seconds. The sample is subjected to repeated opening and closing of the space for 1000 cycles. Each cycle consists of closing the space and opening the space. The force exerted by the mounting material after every 1000 cycles is reported in Newtons (N) when the space is open and closed. The percent retention force is calculated by dividing the retention force after 1000 cycles between the initial retention force.
Flexibili test toThis test is a measure of the flexibility and elasticity of a mounting material, and is an indication of whether or not the material can be used as a sheet or carpet. The test is carried out by taking a 2.54 cm wide strip from the dry sheet or carpet material and rolling it 180 degrees around the 20 mm diameter to see if the sheet or carpet will fracture. The test is successful if the carpet or sheet remains intact without breaking when tested. All the sheets and carpets in the examples pass this test.
EXAMPLE 1 and Comparative Example ClA composition of intumescent mounting material is prepared by adding 3003 grams of expanded vermiculite # 5 (W.R. Grace Co. Cambridge, Massachusetts), 2000 grams of water, 2896 grams of acrylic latex with 60.5% solids(NeocrylMR 2022, available from Zeneca Resins, Wilmington,Massachusetts), and 16 grams of bactericide (Busan "1024, available from Buckman Laboratories, Memphis, Tennessee), to a Ross mixer which includes both a planetary blade and a high shear dispersing blade (model mixer PD 4, available from Charles Ross &Son Co., Hauppauge, New York) The mixer is sealed and placed under a vacuum of 50.7 kiloPascals (kPa) (15 inches of mercury (inches of Hg).) The material is mixed for 20 minutes with both the planetary blade as the dispersion at speed set to 20 on the control panel.After venting air in the vacuum and opening the mixer, 2896 grams of substance that improves adhesion are added to the batch (Snowtack "810A, available from Eka Nobel Canada, Inc., Toronto, Ontario) and 6362 grams of vermiculite ore (obtained from Cometáis, Inc., New York, New York). Again, the mixer is sealed and placed under 50.7 kPa vacuum (15 inches Hg). The batch is mixed for an additional 20 minutes using the planetary and dispersion blades at a set speed of 20. After purging the air in a vacuum, the mixer is opened and the resulting composition is placed in an 18.9 liter plastic container ( 5 gallons) sealed. The composition, on a dry weight basis, is approximately 30.6% intumescent agent, 8.4% acrylic polymer, 9.4% plasticizer, 7.1% adhesion enhancing substance, 14.4% inorganic binder, 0.08% bactericidal and 30% filler material (alumina). The acrylic polymers, plasticizers and the substance that improves adhesion, together, constitute the organic binder (24.9 percent dry weight). Cut sheets or sheets that measure 230 mm by 305 mm by 6.35 mm in thickness (9 inches by 12 inches by 1/4 inches), they are placed on a film release coating and dried in a conversion oven at 95 ° C overnight. Subsequently, the sheets are reduced to a thickness of 3.18 mm (1/8 inch) in thickness by rolling between fixed and movable rollers in a compression roll nip (Sealeze sealer * 1 25 from Seal Priducts, Inc. Naugaruck, Connecticut). The flexible sheet produced in this manner is subsequently cut into a strip measuring 25.4 mm (1 inch) wide by 394 mm (15-1 / 2 inches) long and subjected to the hot agitation test described above. Comparative Example Cl is a 25.4 mm (1 inch) wide strip of a commercially acceptable mounting material (INTERAM automotive assembly carpet "type 100, 3100 grams / m2 available from Minnesota Mining &; Manufacturing Co., St. Paul Minnesota) and is tested by the same method for comparison. The flexible sheet material of the invention lasts the entire 100 hours of the test. The comparative carpet lasts 100 full hours of the test. Example 1 and Comparative Example 1 are tested in the heated cyclic compression test. The results of the test are shown in Table 2.
Table 2The data in Table 2 indicates that the assembly materials of the invention retain a significant amount of the retention force under compression.
EXAMPLE 2An intumescent assembly composition is prepared by adding 191.6 grams of acrylic latex (Neocryl "112022), 191.6 grams of adhesion enhancing substance (Snowtack * ® 810A), 0.9 grams of bactericide (Busan ™ 1024) and 128.6 grams of plasticizer (Sanitisizer 148) to a 3.8-liter (1 gallon) sigma blade Mogul mixer model 4 AN2 from Baker Perkins, now APV Chemical Machinery, Inc. Saginaw, MI) and mixed for 3 minutes.
Subsequently 198.5 grams of expanded vermiculite (expanded vermiculite # 5) are added and mixed for 10 minutes, followed by the addition of 412.5 grams of silica(Crystal grade, from U.S. Silica, Berkeley Springs, WV) and mixed for 20 minutes. Finally 376.3 grams of vermiculite ore (Cometáis, Inc.) are added and mixed for 5 minutes to produce an elastic paste mounting material. The composition of the mounting material, on a dry weight basis, is about 8.7 acrylic polymer, 7.3% adhesion improving substance, 9.7% plasticizer, 0.06% bactericidal, 14.9% inorganic binder, 31% filling material (silica) and 28% intumescent agent. The acrylic polymer, the substance that improves adhesion and the plasticizer together constitute the organic binder (25.7 percent by dry weight). The composition is dispersed in a 4.76 mm (3/16 inch) thick sheet on waxed paper and dried overnight in a convection oven at 95 ° C, then cut into 44.5 mm by 44.5 mm (1-4 cm) boxes. 3/4 inches by 1-3 / 4 inches) to subject it to the actual condition device test (RCFT) described above with a starting space of 3.3 mm. Six cycles of the test are run and the results of the test are shown in the graph in figure 1. Again, Comparative Example Cl is tested as a comparison and the results are shown in the graph in figure 2 with a start space of 3.1 mm. The mounting materials of the invention show sufficient pressure to provide the holding force necessary to hold the monolith in place over the use temperature as compared to the commercially acceptable material.
EXAMPLE 3 and Comparison Example C2A composition of intumescent mounting material is prepared by mixing the composition of Example 1 according to the apparatus and process of Example 2. The resulting sheet material is 4.32 mm thick. The mounting material is tested according to the compression test together with Example 2, which also has a thickness of 4.32 mm and Comparison Examples Cl and C2. Comparison Example C2 is a paste-mounting material (# 2 paste available from Minnesota Mining &Manufacturing Co., St., Paul Minnesota) that has been formed into a sheet having a thickness of 3.68 mm. The test results are shown in the graph in figure 3. Carpet and paste assembly materials show an exponential increase in pressure as the separation between the plates is closed. The mounting materials of the invention show an increase in pressure comparable to the carpet material during the first 25% compression. However, the rate of increase is considerable less than that of C2 carpet and paste materials. The plastic deformation shown by the assembly materials of the invention advantageously decreases the build-up of pressure during canning.
EXAMPLE 4An intumescent mounting material is prepared by adding 47 grams of alumina, 13.6 grams of bentonite clay (200 mesh clay available from Wyoming Bentonite Black Hills Bentonite Co. Casper WY), 13.6 grams of treated graphite (product number 533-61) -26 from Ucar Coal Co. Danbury, Connecticut), 53.8 grams of Inconel 601 wire cut into pieces (Bekaert Shield by Bekaert Corp. Marietta Georgia), 13.6 grams of water, 22.0 grams of acrylic latex (Neocryl "112022), 22 grams of adhesion enhancing substance (Snowtack" 810A ) and 14.4 grams of plasticizer (Sanitisizer * 148) to a polyethylene beaker and mixed manually with a metal spatula until all the ingredients have dispersed well. The composition, on a dry weight basis, is approximately 28.2% filler (alumina), 8.1% clay binder, 13.2% metal fibers, 8.1% intumescent agent, 8% acrylic polymer, 6.7% of substance that improves adhesion, and 8.6% of plasticizer. The acrylic polymer, the substance that improves adhesion and the plasticizer, together, constitute the organic binder (23.3 percent by dry weight). The composition is dispersed to form a sheet having a thickness of 5.0 mm (3/16 inch) on waxed paper and dried for 72 hours in a conversion oven at 95 ° C. Then, samples measuring 44.5 cm by 44.5 cm are cut and tested in RCFT with a start space of 3.25 mm. The results shown in the graph of Figure 4 indicate that the mounting material has an adequate holding force with respect to the temperature range of use.
EXAMPLE 5A composition of intumescent mounting material is prepared by adding 172.0 grams of acrylic latex (NeocrylMR 2022), 172.0 grams of adhesion enhancing substance (Snowtack "810A) and 115.0 grams of plasticizer (Sanitisizer1" * * 148) to a Mogul mixer of 3.8 liters (1 gallon) and then slowly added 178.0 grams of expanded vermiculite (# 5) After mixing for approximately 20 minutes, 93.5 grams of glass microspheres are added (W-1600 Z-Light Spheres Microspheres available from ( Zeelan Industries, Inc. St. Paul, Minnesota) and mixed for 5 minutes, then 337.0 grams of vermiculite ore (Cometáis, Inc.) are added and mixed for 5 minutes.The resulting mounting material has a composition with a base in dry weight of 11.4% of acrylic polymer, 9.6% of substance that improves adhesion, 12.6% of plasticizer, 19.4% of inorganic binder, 36.8% of intumescent material, and 10.2% of microspheres of v The acrylic polymer, the substance that improves adhesion and the plasticizer, together, constitute the organic binder (33.6 percent by dry weight). A sheet of 5.0 mm thick material is prepared as in Example 4 and tested in the RCFT test with an initial gap of 3.7 mm. The results are shown in figure 5.
EXAMPLE 6Moisture intumescent mounting composition of Example 2 is pressed into a three dimensional wire mesh(0.11 in diameter, density of 48, shrinkage # 12 ofMETEX, Edison, NJ). The composite material is dried overnight in a convection oven at 95 ° C and then tested according to RCFT with an initial gap of 5.27 mm. The results are shown in the graph of figure 6.
EXAMPLE 7An intumescent carpet or mat composition is prepared by adding 46 grams of ceramic fibers (silica ceramic fiber and alumina 7000M available fromCarborundum, Niagara Falls, N.Y.) and 2500 milliliters of water to a mixer (Waring CB-6 mixer model 32BL39) and mixed at low speed for 20 seconds. Subsequently the mixture is poured into a cylindrical container together with an additional 1000 ml of water which is used to rinse the mixing vessel. The mixture is suspended when mixed with a laboratory stirrer at a speed set at 4 (Yamato Labo-Stirrer, model LR-41D). Then 75 grams of acrylic latex (Rhoplex acrylic latex "* HA-8, available from Rohm and Haas, Philadelphia, Pennsylvania) and 1.9 grams of sodium aluminate (Nalco" 2372 available from Nalco Chemical Co. Chicago, are added to the mixture. IL) and mixed for 1 minute. Then, 16.7 grams of a solution of 50% solids aluminum sulfate (liquid aluminum sulfate "Papermakers" available from American Cyanamid Co., Cloquet, Minnesota) is added and mixed for 1 minute, followed by the addition of 77.1 grams of vermiculite ore(Cometáis, Inc.). The speed is increased, from the mixer to a setting of 6 for 1 minute. The mixer is then turned off and the mixture is poured rapidly into a 20.3 cm (8 inch by 8 inch) manual sheet former (Williams Apparatus Co. Watertown, NY) having a 40 mesh screen, and drained . The formed sheet is then placed between sheets of blotting paper and pressed at a pressure of 413.7 kiloPascals (60 psi) in a pneumatic press (Mead Fluid Dynamics Chicago, ILL). The formed carpet is then dried on a hot plate for 1 to 2 hours. The carpet mounting material is tested according to RCFT with an initial gap of 3.8 mm and the results are shown in the graph of figure 7.
EXAMPLE 8The intumescent composition of Example 5 is pressed into a woven metal mesh (Inconel woven wire mesh (Inconel 600 wire 0.15 mm) 0.006 inches) in diameter, N34, 11 cpi mesh, 3.8 cm (1.5 inches) wide, available of ACS Industries, Inc., Woonsocket, Rl) to form a mounting composite having a thickness of 6 mm. A square of 44.5 mm by 44.5 mm is cut from the composite sheet. Then two strips of the same metal mesh measuring 44.5 mm by 38 mm are wound around opposite edges of a square so that each one overlaps the edge by approximately 17 mm. The composite sample has a wire mesh embedded in the mounting materials as well as a wire mesh wound around the two edges and tested according to RCFT with an initial gap of 4.78 mm. The results are shown in the graph of Figure 8. Furthermore, it is noted that the wire mesh reduces blow and drop of the mounting material along the rolled edges during the expansion of the sample after heating.
COMPARATIVE EXAMPLE C3An intumescent composition is prepared when mixing1315. 4 grams of acrylic latex and 389.7 grams of vermiculite spread in a Mogul 3.8-liter mixer(1 gallon) for approximately 45 minutes. Then 294.9 grams of vermiculite ore are added and mixed for approximately 8 minutes. The resulting paste has a composition of 53.8% organic binder, 26.3% inorganic binder and 19.9% intumescent material. The composition is dispersed on waxed paper to a thickness of 4 mm (0.16 inches) in the form of a sheet which is dried overnight in a convection oven at 95 CC. The sheet material is tested in a real condition device test with an initial space of 3.61 mm. The results in Figure 9 show that the amounts of organic binders exceed about 50% and decrease the holding force during the cooling period of the first cycle.
COMPARATIVE EXAMPLE C4An intumescent composition is prepared as follows, mix 2300 grams of water, 3185.5 grams of acrylic latex (Neocryl "2022), 2141.8 grams of plasticizer (Santisizer" 148), 16 grams of bactericide (Busan "1024), 2433.4 grams of fibers ceramics (ceramic fibers 7000M, available from Carborundum, Niagara Falls, New York) and 25 grams of defoamer (defoamer Foamaster 111, Henkel Process Chemicals, Inc., Morristown, NJ) for 20 minutes on a Ross mixer, then 1094.8 grams are added of expanded vermiculite (# 5) and 65.7 grams of Methocel K4M (hydropropylmethylcellulose, Dow Chemical, Midland, MI) and mixed for 10 minutes, then 1338.6 grams of Dixie clay were added.
(R.T. Vanderbilt Co., Inc., Norwalk, Connecticut), 5475.2 grams of Ceepree C200 glass (Brunner Mond &Co., Ltd.,Cheshire, UK) and 5475.2 grams of tabular alumina (alumina mesh -48 +200, Alcoa, Bauxite, AR) and mixed for 15 minutes. Then add 3185.5 grams of the adhesion enhancing substance (Snowtack "810A) and 25 grams of defoamer (Foamaster 111) and mix for 10 minutes After removing the mixer, 150 grams of the mixture is placed in a beaker 500 ml and manually mixed with 50 grams of vermiculite type "D." A 5 mm thick sheet is punched on waxed paper and dried overnight in a convection oven. 44.5 mm of the sheet and are used for the RCFT test with an initial separation of 4.1 mm The percent dry weight of some of the components is as follows: 18.3% glass binder, 19.0% organic binder, 8.2% of ceramic fiber, inorganic binder and 3.7% micaceous inorganic binder.In the first cycle the retention force is maintained as the vermiculite expands and is maintained during cooling as the space decreases and the Since the glass binder is not flexible, the retention force fails (decreases to zero) at high temperature because the glass binder fails in the second cycle, this failure occurs even though there are significant amounts of ceramic fibers and micaceous binder in the formula. The results are shown in figure 10.
EXAMPLE 9An intumescent composition is prepared as follows. 341.1 grams of acrylic latex (Neocryl "11 2022), 191.6 of substance that improves adhesion (Snowtack" 810A), 128.6 grams of plasticizer are added(Santisizer "148), 305.5 grams of ceramic fibers(7000M), 305.5 grams of alumina and 50 grams of bentonite to a Mogul mixer and mixed for 40 minutes with the ceramic fiber added slowly during the firstminutes. Subsequently, 376.3 grams of vermiculite type "D" are added and mixed for 10 minutes. A 5 mm thick sheet is punched out on waxed paper and dried overnight in a convection oven at 95 ° C. A sample of 44.5 mm by 44.5 mm of the sheet is cut for test in RCFT with an initial space of 3.2 mm. The dry weight percent of the organic binder is 29.4% (14.1% acrylic resin, 6.5% adhesion improving substance and 8.8% plasticizer). The dry weight percent of inorganic binder is 24.2% (20.8% ceramic fiber, 3.4% bentonite); the dry weight percent of the filling materials is 20.8% (alumina). The dry weight percent of vermiculite type "D" is 25.7%. The results of the test are shown in Figure 11. It will be apparent to those familiar with the art that various modifications and variations may be made to the method and article of the present invention without departing from the spirit or scope of the invention. Therefore, it is considered that the present invention encompasses the modifications and variations of this invention with the proviso that they fall within the scope of the appended claims and their equivalents. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, property is claimed as contained in the following: