Stock material or miscellaneous articles – Composite – Of metal
Reexamination Certificate
2002-11-20
2004-10-05
Zimmerman, John J. (Department: 1775)
Stock material or miscellaneous articles
Composite
Of metal
C428S689000, C428S697000, C106S014050, C106S600000, C501S015000, C501S053000, C501S017000, C501S078000, C501S073000, C065S036000, C065S059100, C427S375000, C427S376200
Reexamination Certificate
active
06800375
ABSTRACT:
FIELD OF THE INVENTION
The instant invention relates to methods and articles for fusing electrical, heat, chemical, corrosive, scratch resistant, non-VOC deterioration of pigmented, permanent coloration glass to motor vehicle parts and to construction parts, and particularly to articles and methods using glass porcelain enamel.
BACKGROUND
Because of its highly competitive nature, the motor vehicle industry as well as the marine industry has long endeavored to provide longer and more comprehensive manufacturer' warranties for their finished products. Their goal has been to increase the useful life of critical operational parts in their vehicles to exceed anticipated warranty periods of 100,000 miles and 10 years.
Various grades of stainless steel, aluminized steel, carbon steel, and titanium-steel alloys have been tested in an effort to accomplish their goals. Success from these efforts has, at best, been limited. Therefore, the primary challenge facing these manufacturers is the ongoing search for a protective coating for these critical metal parts in order to ensure that the useful life of these parts does not end prematurely through corrosion, metal fatigue or both.
Engineers for motor vehicle manufacturers are also faced with increasing environmental demands from state and Federal agencies concerned with the use of hazardous and toxic materials that exist in the solvents used in these coatings. It is anticipated that chrome plating and other plating processes will be banned in the near future because of the toxic by-products produced and the dangerous environment in which plating workers have to labor.
The predominant metals used in vehicles are stainless steel, carbonized stainless steel, carbon steel, aluminum, cast aluminum, gray iron and cast iron. Motor vehicle and marine manufacturers acknowledge that these metals must be protected from such harsh external elements as salt, rain, snow hail and heat, as well as the chemicals used internally to make their vehicles operational, including, but not limited to, battery acid, oil, gasoline, diesel fuel, brake fluid, hydraulic and transmission fluids.
The manufacturers seek a coating which can be produced and applied in an environmentally friendly manner and can protect these metals from such destructive forces (both internally and externally) as corrosion, chemical attacks, high heat and sub-zero cold. The coating must be able to expand and contract as the metals expand and contract and must be impervious to penetration from salt, gravel, water and chemicals. Thermal shock caused by extreme heat and cold can cause most coatings to crack, peel or check causing the metal to be exposed to the elements.
Presently the manufacturers use the following protective coatings on their vehicles:
1. Solvent Based Coatings. These coatings have a high level of Volatile Organic Compounds (VOCs) and thus the applicators are required to file an environmental impact statement and pay a tax or license fee in order to use these products. The application must take place in a highly controlled and enclosed environment that is properly ventilated. The fumes must be filtered or destroyed before being emitted into the atmosphere. Employees must wear protective clothing and an approved breathing apparatus while applying the coating. These membrane coatings historically have not had the durability to pass a scratch test or a heat test. Some coatings even fail to pass thermo-shock and gravel meter tests.
2. Water Borne Coatings. These membrane coatings have met the VOC guidelines of state and Federal environmental agencies, but, depending on the contents, Hazardous Air Pollutants (HAPs) can make even water-based coatings hazardous. When applied, these coatings can be either air-dried or heat-cured at low temperatures (250 degrees Fahrenheit to 650 degrees Fahrenheit). After application, operating temperatures of 1,000 degrees Fahrenheit to 1,100 degrees Fahrenheit will cause the coating to fail whereupon the metal will begin to corrode. This type of coating is not scratch resistant or chemical resistant. When exposed to high heat, the zinc undercoat is prone to failure and will peal off. If the coating is applied without a zinc primer, chemicals will be able to penetrate to the metal surface and will undercut the coating with rust.
3. Urethane Coatings. This is a rubber-based synthetic resin containing either water or solvent. These types of coatings perform well to protect against weathering and salt penetration. These coatings, however, to not hold up when exposed to ethanol, glycols, brake fluids or battery acids. High heat will cause these coatings to break down.
4. Powder Coatings. These coatings are applied to vehicle parts in dry form. Some powder coats are silicate based and must be monitored by state and Federal environmental agencies due to the HAPs contained in the silicate compounds that can escape into the air when applied. The rooms where the silicate-based powder are applied must be well ventilated and filtered. Protective clothing and an approved breathing apparatus must be work at all times for worker' protection. At application, these coatings are baked on at temperatures of 500 to 850 degrees Fahrenheit. These coatings have shown some durability to weather but tend to fail when attacked by chemicals and salt. These coatings are not scratch resistant.
5. Epoxy Coatings. If oil-based, these coatings are high in VOCs. If water-based, they have HAP problems. In either case, they have the attendant environmental safety problems that must be satisfied as previously discussed. Both types of coatings perform well when attacked by chemicals, but fail when exposed to ultra-violet light or temperatures in excess of 500 degrees Fahrenheit.
Vehicle manufacturers have established exhaustive testing programs to ensure that critical parts are capable of lasting and performing for a minimum period of time. In some cases these tests simulate the wear and tear (without part failure) which can be expected to occur during a minimum of 100,000 miles of driving and in some cases as much as 1,000,000 miles. Modern day parts must be able to withstand cold temperatures as low as −30 degrees C. and hot temperatures as high as 450 degrees C.; they must be abrasion resistant, resistant to a wide variety of chemicals and salts.
The heat generated by the exhaust systems has troubled the automobiles as well as the trucking industries. The exhaust system of both gasoline and diesel engines are subject to very severe operating conditions, due to the high temperatures (1000 degrees Fahrenheit to 1450 Fahrenheit) of exhaust gases. The behavior of steel at high temperatures, i.e., expansion, creep, thermal shock, mechanical fatigue, oxidation and corrosion resistance are factors determining reliability.
Catalysts placed in a ceramic cone create a heat source for the exhaust gases to light off any carbon monoxide, nitrogen oxide, and unburned hydrocarbons. The temperature of these gases internally passing through the exhaust system of gasoline engines reaches 1400 degrees to 1800 degrees Fahrenheit at the catalytic converter. This temperature must be maintained (volume of area of heat) to destroy the three gasses mentioned above.
If a constant insulated heat source is maintained from the engines manifold to the catalytic converter a faster light-off is created thus reducing exhaust pollutants being emitted from the engine exhaust pipe into the atmosphere. Before light-off begins, a temperature of 400 to 600 degrees Fahrenheit must be achieved, or all of the pollutants are emitted into the atmosphere. To improve this light-off action created by a catalytic converter, automobile manufacturers moved the converter closer to the engine. This generated heat problems in the firewall area under the hood. Some manufacturers used two to three smaller converters to extend the heating area of the exhaust system thus improving the reduction of pollutants. This also generated additional heat problems in the firewall area. By increasing the heat under the hood of the aut
Blackwell-Rudasill G. A.
Rylander Kurt M.
Zimmerman John J.
LandOfFree
Chemical resistant glass fusing composition and process for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Chemical resistant glass fusing composition and process for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chemical resistant glass fusing composition and process for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3295203