Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Noninterengaged fiber-containing paper-free web or sheet...
Patent
1982-11-22
1984-06-26
Ives, P. C.
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Noninterengaged fiber-containing paper-free web or sheet...
428443, 428444, 428465, 428457, 428543, 428426, 106 1418, 523152, 192107M, 188251H, 4273881, B32B 2700, B32B 904, C04B 902, F16D 6900
Patent
active
044566506
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The method of this invention relates to the use of alkanolamine-carboxylic acid salts as coatings for friction materials which during use, contact rustable metals. More particularly, the friction material is contacted with an aqueous solution comprising at least about 0.05 weight percent, based on the weight of the solution, alkanolamine-carboxylic acid salts and subsequently dried to remove water, leaving a coating comprising alkanolamine-carboxylic acid salts on the friction material.
BACKGROUND ART
During use, friction materials, such as brake linings or clutch facings, come in contact with metals, e.g., cast iron. Corrosion of such ferrous metals may cause adhesion (stiction) of the friction material to the metal when they are allowed to contact one another for a period of time. Generally, such corrosion and stiction occur before the metal and friction material have received substantial sustained wear. One longstanding approach to preventing clutch facing stiction comprises coating the friction material with sodium nitrite. However, recent and anticipated agency recommendations have created a need to replace sodium nitrite which is ecologically less than desirable. It also does not appear to retain its corrosion resistant properties longer than a few weeks (often before the friction material is operating on the vehicle), oxidizing at ambient temperatures to the nitrate. However, we have found that coatings comprising alkanolamine-carboxylic acid salts on friction materials are significantly more effective in preventing such corrosion bonding and that they maintain these properties after application and during friction material use for a substantially greater period of time.
Alkanolamine-carboxylic acid salts have been used as flame retardants in acrylic fibers, however more usually as corrosion inhibitors in lubricants, cutting fluids, radiator coolants, and metal surface cleaning-treating compositions. U.S. Pat. No. 3,769,214 to Davis teaches aqueous compositions, adapted for use as coolants and lubricants in metal machining operations, comprising alkanolamine salts of carboxylic acids.
DISCLOSURE OF THE INVENTION
The invention is directed to a method for using alkanolamine-carboxylic acid salts as a coating for friction materials which during use contact rustable metals. The coating on the friction material acts to prevent corrosion or corrosion product build up on the metal contacting the friction material. The method of this application comprises:
(A) contacting the friction material with an aqueous solution comprising at least about 0.05, preferably between about 0.1 and about 10.0, most preferably between about 0.2 and about 5.0 weight percent, based on the weight of the solution, of alkanolamine-carboxylic acid salts; and
(B) evaportating water from aqueous coating on the friction material so as to leave the friction material with a coating comprising alkanolamine-carboxylic acid salts.
The alkanolamine-carboxylic acid salts are the reaction product of alkanolamines, preferably selected from secondary and tertiary alkanolamines, and C.sub.4 -C.sub.20, preferably C.sub.6 -C.sub.10, carboxylic acids. More preferably, the alkanolamine reactant used to form the salt is a secondary alkanolamine, most preferably being diethanolamine. The carboxylic acid reactant may be selected from aliphatic and aromatic carboxylic acids or mixtures thereof. Preferably the salts comprise mixtures of alkanolamine-aliphatic carboxylic acid salts and alkanolamine-aromatic carboxylic acid salts, wherein additionally more preferably this mixture contains greater than about 50 percent of the aromatic carboxylic acids salts. Most preferably, the carboxylic acid reactant of the salts are benzoic acid and heptanoic acid.
The invention is also directed to friction materials coated according to the method disclosed above.
Advantageously, the salts can be applied to the friction material at very low concentrations and provide superior prevention of such corrosion related phenomena as stiction.
The alkanola
REFERENCES:
patent: 3326822 (1967-06-01), Albertson
patent: 3769214 (1973-10-01), Davis
patent: 4045608 (1977-08-01), Todd
patent: 4073618 (1978-02-01), Doi et al.
patent: 4192769 (1980-03-01), Jahnke
patent: 4233176 (1980-11-01), Conner, Sr.
patent: 4355068 (1982-10-01), Beyer et al.
"Sodium Replacement-The State of the Art," C. J. Fette, Journal of the American Society of Lubrication Engineers, vol. 35, 11, 625-627.
"Anti Corrosion Paper", Ikhelson et al.; Chemical Abstracts, vol. 93, 1980 93:169993g.
"Composition for Impregnating a Base Paper Used for Manufacture of Anticorrosion Paper" Ikhelson et al.; Chemical Abstracts, vol. 93, 1980, 93:169994h.
"Corrosion Inhibition of Metal Products Stored in Open Atmosphere", Jpn Kokai Tokkyo; Chemical Abstracts, vol. 93, 1980, p. 224, 93:136155g.
"Fire-Resistant Acrylic Fibers and their Products" Kazuo et al., Chemical Abstracts, vol. 77, 1972, p. 66, 127990t.
"Liquid Temporary Corrosion-Inhibiting and Cleaning Surface Treating Agents Having a High Water Tolerance for Metals, Especially Steel", Atterby; Chemical Abstracts, vol. 78, 1973, pp. 191-192, 78:46588m.
"Corrosion Test of Various Derivatives of Aromatic Carboxylic Acids", Saga et al., Chemical Abstracts, vol. 91, 1979, p. 193, 91:110903h.
"Corrosion-Inhibiting Compositions for Metal Working", Martin et al., Chemical Abstracts, vol. 84, 1976, p. 177, 84:470009.
Anderson Arnold E.
Melotik Donald J.
Weintraub Marvin H.
Ford Motor Company
Ives P. C.
May Roger L.
Melotik Lorraine S.
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