Abrasive tool making process – material – or composition – With inorganic material
Reexamination Certificate
2002-08-13
2003-10-28
Marcheschi, Michael (Department: 1755)
Abrasive tool making process, material, or composition
With inorganic material
C051S308000, C051S309000, C106S003000, C106S010000, C134S006000, C451S036000
Reexamination Certificate
active
06638327
ABSTRACT:
FIELD
The present invention relates to a method for repairing and lustering defects on a hydrophilic coat surface and, in particular, to a method for repairing and lustering defects on a hydrophilic coat surface that requires a very fine finish, such as an automobile coat surface.
BACKGROUND
Painting is generally performed on an automobile surface for the purpose of imparting surface protection, desired colors, and aesthetic appearance. Painting is an operation to spread a paint (i.e., is a resin composition) over the surface of an automobile body and to harden the paint to form a continuous resin-coated film having an approximately uniform thickness. The resin-coated film formed on the surface of an object by painting is called a coat.
If some functional hindrance of the paint (e.g., foaming, adhesion of dust, or the like) occurs during the painting step, the uniformity, continuity, or the surface flatness of the coat to be formed is inhibited, and defects such as haze marks, recesses, and wounds may be generated on the coat surface. Defects are also generated on the coat surface when the uniformity, the continuity, or the surface flatness of the coat is altered by friction or collision of the automobile body after the coat is formed. If the defects are present on the coat surface, the aesthetic appearance of the automobile body is deteriorated, and the value of the automobile is decreased. For this reason, defects on the coat surface must be repaired and polished.
Japanese Patent Laid-open Publication No. 02-269791 discloses a method for repairing the defects on the coat surface. According to this method, the defects of the coat are removed by first sanding with a very fine grade polishing material. Next, the trace of the removed defects is buffed using a buffing composition to remove the scratches produced by the sanding step. Finally, the residual buffing composition is removed using a cotton cloth, thereby producing a uniform, glossy finish. One suitable buffing composition for use in this method is commercially available under the trade designation “FINESSE-IT” from Minnesota Mining and Manufacturing Company.
Various functional paints have been developed in recent years, and a coat is known which exhibits an excellent antifouling property against fouling substances specific to urban areas (e.g., smoke and exhaust gas). For example, “Painting Technology”, Vol. 31, No. 7 (1996), pp. 268-273 explains a mechanism of the antifouling function exhibited by such a low-fouling type coat against urban fouling substances. Since the low-fouling type coat has a high surface energy and shows a hydrophilic and oil-repellent property, oleophilic fouling substances (e.g., smoke and exhaust gas) are unlikely to adhere to the coat and, if they adhere, are easily washed away by rain or the like.
When defects are generated on the surface of the low-fouling type coat and if an attempt is made to repair the defects by a conventional method, problems arise such as insufficient removal of the defects, poor finish after repairing, and deterioration of the antifouling property of the coat against urban fouling substances after repairing. These problems are raised because oleophilic ingredients (e.g., aliphatic hydrocarbon and petroleum-based solvents) are contained in the buffing composition used in the step of buffing the coat surface. These oleophilic ingredients are not compatible with the hydrophilic coat and have an insufficient polish promoting function. Once the oleophilic ingredients penetrate into the hydrophilic coat they cannot be easily removed, so that the hydrophilic and oil-repellent function is deteriorated on a portion of the coat surface where the oleophilic ingredients have penetrated. On the other hand, if the oleophilic ingredients are removed from the buffing composition, removal of the defects by the buffing step will be insufficient, thereby giving a poor finish after repairing
SUMMARY
The present invention provides a method for repairing and lustering defects on a coat surface, by which method the defects on a hydrophilic coat surface is sufficiently removed with good finish after repairing, and the antifouling function of the hydrophilic coat against urban fouling substances is not deteriorated. The method of the present invention comprisies the steps of applying a buffing composition on a hydrophilic coat surface; and buffing the hydrophilic coat surface to which the buffing composition has been applied, wherein said buffing composition is an aqueous composition which comprises water and a water-soluble high-boiling-point liquid organic compound, and further contains either a combination of abrasive particles and a dispersant, a lustering agent, or both.
DETAILED DESCRIPTION
The buffing composition for use with the method of the present invention is an aqueous composition containing water and a water-soluble high-boiling-point liquid organic compound, and further containing either a combination of abrasive particles and a dispersant, a lustering agent, or both.
Water-Soluble High-Boiling-Point Liquid Organic Compound:
Preferred water-soluble high-boiling-point liquid organic compounds, are those that are effective in swelling and softening the hydrophilic coat. Softening the hydrophilic coat improves the polishing performance of the buffing composition.
The hydrophilic coat may be generally an acrylic melamine resin, an aminoalkyd resin, a urethane resin, or the like. The hardness of such a coat is generally H to 2H (JIS (1979, K5400)) before it is swollen with the water-soluble high-boiling-point liquid organic compound. On the other hand, after it is swollen with the water-soluble high-boiling-point liquid organic compound, the hardness of the coat is preferably about B in view of promoting the polishing.
Since the buffing step is generally carried out for 1 to 5 minutes at an ambient temperature of 25 to 60° C., the water-soluble high-boiling-point liquid organic compound must be slightly volatile to such a degree that it is not dried during the buffing step. Accordingly, the water-soluble high-boiling-point liquid organic compound preferably has a boiling point of not less than 100° C., more preferably not less than 130° C.
The water-soluble high-boiling-point liquid organic compound preferably has a carbon number of 3 to 12, more preferably 3 to 6. If the carbon number is less than 3, the boiling point will be too low and it will be dried during the polishing step. If the carbon number exceeds 12, the ability of the water-soluble high boiling-point liquid organic compound to swell the coat will decrease.
Also, the water-soluble high-boiling-point liquid organic compound is preferably one that can be easily washed away with water with little remaining in the inside of the coat, even if it adheres to the coat surface. Further, even if a small amount remains, it is preferably one that does not give an adverse effect on the hydrophilic, oil-repellent function of the hydrophilic coat.
Preferable examples of water-soluble high-boiling-point liquid organic compounds are polyhydric alcohols, hydroxyketones, and ether or ester derivatives of polyhydric alcohols. Specific examples include ethylene glycol diglycidyl ether, ethylene glycol dimethyl ether, ethylene glycol monoacetate, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monomethoxymethyl ether, ethylene chlorohydrin, glycerol, diethylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monomethyl ether, propylene glycol monobutyl ether, diacetone alcohol, propylene glycol monomethyl ether, and others.
Among these, especially preferable water-soluble high-boiling-point liquid organic compounds are diacetone alcohol and propylene glycol monomethyl ether. These are exce
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