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United States Patent [i9j
Sarokin et al.
 PAINT MASKING MATERIAL COMPRISING A FIBROUS BASE COATED ON ONE SURFACE WITH A PAINT-PERMEABLE COATING AND COATED ON THE OTHER SURFACE WITH A PAINT-IMPERVIOUS COATING
 Inventors: Steven D. Sarokin, Green Bay, Wis.;
John E. Dayton, Jr., Beaumont, Tex.
 Assignee: International Paper Company, Purchase, N.Y.
 Appl. No.: 676,749
 Filed: Mar. 28,1991
 Int. Cl.« D21F 11/00; B32B 5/16;
B32B 5/24; B32B 7/12
 U.S. CI 428/283; 162/135;
162/137; 428/284; 428/287; 428/311.1;
 Field of Search 428/212, 248, 246, 286,
428/288, 532, 509, 78, 40, 42, 533, 534, 535, 537.5, 283, 284, 287, 311.1, 311.7, 318.4; 106/139, 2; 427/352, 154; 162/135, 137
 References Cited
U.S. PATENT DOCUMENTS 1,683,453 9/1928 Farrell .
1,723,581 8/1929 Ruderman 106/139
1,861,165 5/1932 Ryan et al 106/2
[ii] Patent Number: 5,415,923  Date of Patent: May 16, 1995
2,082,791 6/1937 Copeman 280/152
2,803,557 8/1957 Martin et al 427/208.4
3,152,921 10/1964 Gallagher et al 428/167
3,846,172 11/1974 Fossati 427/352
4,010,307 3/1977 Canard et al 524/25
4,012,543 3/1977 Ranger et al 427/361
4,112,192 9/1978 Vreeland 428/511
4,187,219 2/1980 Maher 260/17.4 ST
4,241,143 12/1980 Ashie et al 428/512
4,265,969 5/1981 Yasuda et al 428/342
4,279,964 7/1981 Heller 428/496
4,308,320 12/1981 Schiller 428/511
4,347,266 8/1982 Norman et al 427/154
4,861,652 8/1989 Lippert et al 428/286
4,921,740 5/1990 Falconer et al 428/40
5,104,711 4/1992 Marsek 428/78
Primary Examiner—James D. Withers
Attorney, Agent, or Firm—Luedeka, Neely & Graham
An improved masking material useful in spray-painting operations comprising an absorptive reservoir defined by a fibrous base sheet to one surface of which there is applied a first coating that defines a less than complete barrier to the transfer of paint to said base sheet and to the opposite surface of which there is applied a second coating that defines a substantially complete barrier to the strike-through of paint to an underlying surface sought to be protected from the paint.
5 Claims, 1 Drawing Sheet
PAINT MASKING MATERIAL COMPRISING A FIBROUS BASE COATED ON ONE SURFACE WITH A PAINT-PERMEABLE COATING AND COATED ON THE OTHER SURFACE WITH A 5 PAINT-IMPERVIOUS COATTNG
This invention relates to sheet or web material which is employed to cover and mask off an area of an object being spray painted to prevent the paint from contact- 10 ing such covered area.
In the spray painting of objects, for example motor vehicles or portions thereof, it is commonly desired that certain area or areas of the object not receive the sprayed paint. To avoid such, the areas to be protected 15 may be covered with a mask which is secured over the area to be protected from paint, as by means of edge taping, and which most usually remains in such position until the paint applied to the surrounding area is dry or cured, as the case may be. Thereafter the mask is re- 20 moved, leaving the protected area free of paint. Stated generally, in the spray paint industry paints are referred to as acrylic enamels, acrylic lacquers and acrylic urethanes. End users of these paints commonly dilute the paint with solvent (xylene being the most aggressive) 25 between about 35% to 65%.
In the prior art, newspaper, meat wrapping paper, thermoplastic sheets or webs, and like flat materials have been employed as masks. Several of these prior art materials are essentially impervious to the paint and/or 30 to one or more of the components of the paint, such as the various solvents used in "oil-based" or in "latex" paints and therefore serve to prevent strike-through of the paint onto the surface underlying the mask. These materials, however, are not absorptive of the paint or its 35 components so that the paint tends to accumulate on the material and eventually flow or drip from the mask onto the painted surface and thereby develop "runs" on the painted surface. Newspaper, while absorptive to a degree greater than thermoplastic sheet, for example, also 40 tends to accumulate paint and develop "runs". Moreover, newspaper and certain other of the presently used mask materials tend to have loose fibers on their surfaces which during the spray painting operation are dislodged and blown onto the freshly painted surface 45 and thereby destroying the finish of the painted surface. This problem is exacerbated when the mask is in place when the object to be painted is first subjected to wet sanding or the like in preparation for painting. Still further, thermoplastics and materials coated with low- 50 temperature resistant coatings, such as meat wrapping papers, can not withstand the heat of curing of paint and tend to adhere to the underlying surface of the object being painted, thereby presenting a serious problem of their removal. These and certain other mask materials 55 used heretofore further are relatively inflexible which creates difficulty in positioning the mask onto and securing the same to the object over the precise area from which the paint is to be excluded.
It is therefore an object of the present invention to 60 provide an improved spray-painting masking material which overcomes the disadvantages of the prior art in that it is flexible, absorptive of the paint, and presents a barrier to the strike-through of the paint onto the underlying surface of the object. It is another object of the 65 present invention to provide a masking material of the type described which is relatively inexpensive. It is another object to provide a masking material of the type
described wherein defiberization of the material is substantially eliminated, even in the presence of wet sanding. It is another object to provide a masking material of the type described which is heat resistant and can be left in place during heat curing of the painted surface.
Further objects and advantages of the present invention will be recognized from the following description, including the drawings in which:
FIG. 1 is a cutaway representation of a portion of an object to be painted and which has applied thereto a masking material overlying an area which is to be protected from the paint; and
FIG. 2 is a representation, in section, of a masking material embodying various of the features of the present invention.
In accordance with the present invention there is provided an improved masking material for use in protecting a selected area or areas of an object to be spray painted from the paint or one or more components of the paint. This improved masking material comprises a base sheet or web of a fibrous material such as cellulosic or other fibers which are absorptive of the paint and/or the components of the paint and provides a collection reservoir for the paint and/or its components that may be deposited thereon during a painting operation. This base sheet or web further includes on one of its flat surfaces a coating of a composition applied thereto in a manner and quantity which provides a partial barrier to the paint and/or its components, but which permits a major portion of such to penetrate such coating and be absorbed by the base. This coating further serves to bind the fibers of the base to the base and prevent their dislodgment in the course of preparing the object for painting (e.g. wet sanding), or in the course of the actual painting and/or curing operations.
The present improved masking material further includes on the second of its flat surfaces a further and different coating which is of a nature as to define a substantially complete barrier to the strike-through of paint and/or the components of the paint from the base sheet onto the protected surface underlying the mask. This latter coating comprises a combination of pigmenttype matter, such as clay, and a binder that is heat resistant. Each of the coatings applied to the opposite fiat surfaces of the base are of a nature such that the completed masking material is sufficiently flexible to be readily positioned and secured to the object in overlying relationship to the area or areas to be protected from the paint.
For purposes of the present discussion, the term "sheet" is to be deemed in include a discrete sheet and a continuous web unless otherwise indicated to the contrary.
With reference to the Figures, in FIG. 1 there is depicted a portion of a motor vehicle door 10 including a window 12 provided therein. As depicted, the door and window are prepared for spray painting by the placement of a mask 14 in position overlying the window 12 and held in place as by tape 15. Thereafter both the door and the covered window are sprayed with paint so that the mask receives an application of paint which is substantially of the same quantity per unit area as that applied to the door itself. Often multiple coatings of paint are applied with sanding or other surface treatment of the painted surface between coats.
Referring to FIG. 2, a masking material 19 in accordance with the present invention comprises a base sheet 20 having first and second flat opposite surfaces 22 and
24, respectively. As depicted, the first surface 22 has the binder must impart a degree of water and/or solvent applied thereto a first coating 26 and the second surface repellency to the starch in order to develop the desired 24 has applied thereto a second coating 28. As referred partial barrier characteristics of the first coating, to hereinabove and as will be further discussed hereinaf- Further, the present masking material includes a secter, the first coating defines less than a complete barrier 5 ond coating 28 applied to the second surface 24 of the to the flow of paint therethrough and into the base base sheet 20. Such second coating defines a substansheet, while the second coating defines a substantially tially complete barrier to the passage of paint therecomplete barrier to the passage of paint from the base through and comprises a relatively inert filler such as sheet to the underlying protected surface, e.g. the win- clay combined with a polymeric binder. Fillers such as dow 12. Recalling also that the base sheet comprises 10 kaolin, silica, titanium dioxide and other like fillers may absorbent fibrous matter, it will be recognized that be substituted for or used in combination with clay. A when any cut edges of the masking material are taped suitable binder comprises a styrene/butadiene composiclosed, the coatings and base sheet define a capture tion in which the styrene comprises between about 10% reservoir for paint and/or components of the paint. As and about 90% of the solids content. Employing a styreindicated by the several arrows 27 leading through the 15 ne/butadiene binder, a preferred composition for the coating 26 of FIG. 2, a major portion of the paint re- second coating comprises between about 10 to about 80 ceived by the masking material passes through the first parts by weight of delaminated clay (available from coating 26 and is captured interiorly of the base sheet 20 Engelhard Clay) in combination with between about 10 thereby preventing accumulation of such quantities of and about 90 parts by weight of No. 4 clay (65% <2 paint on the exposed surface 30 of the coating 26 as 20 microns) available from Georgia Kaolin. The clays would permit the flow of such paint from the masking function as fillers and to impart a white color to the material and onto the unprotected areas of the object second coating thereby making the second coating recbeing painted. ognizable visually by the end user. For those applica
A base sheet 20 of the present invention may be tions of the masking material where the mask is to reformed of any suitable material that will absorb paints. 25 main in position during a heat curing operation for the Preferred absorbent materials are cellulosic or polyester paint, the composition of such second coating is sefibers, or combinations thereof. Most preferred are eel- lected to withstand the elevated temperature of the lulosic fibers such as those obtained from wood. The curing operation, e.g. 2O0°-3OO° F. The above noted base sheet may be formed by conventional papermaking preferred coating composition will withstand such curmethods and employing conventional papermaking 30 ing temperatures without material degradation of the machines. Nonfibrous materials have been found to not masking material such that the masking material tends take up the paint as required, presumably due to their to adhere to the underlying protected surface. A coatabsorbency properties and/or their inability to define ing composition having between about 20 and about capillary-like channels for absorbing the paint within a 80% by weight solids content, when applied to the base time period sufficient to prevent the undesired accumu- 35 sheet in a quantity of between about 3 and about 10 lbs. lation of the paint on the exposed surface of the masking per 3,000 ft2 of base sheet surface has been found to material. One suitable base sheet comprises cellulosic provide a coating which defines a substantially comkraft pulp formed on a Fourdrinier papermaking ma- plete barrier to either oil or latex-based paints. It will.be chine and subsequently dried to provide a cellulosic recognized that for a given base sheet reducing the sheet having a basis weight of between about 10 and 40 solids content of the coating composition will reduce about 50 lb/3000 ft2. the porosity of the applied coating, as will the applica
The base sheet 20 of the present invention has applied tion of lesser quantities of the overall composition to the
to its first surface 22 a sizing composition to develop a sheet. Thus, one needs to select from the stated range
first coating 26 which defines a less than complete bar- that combination of solids content and total quantity of
rier to the passage of paint and/or one or more of the 45 applied coating as will achieve the desired porosity,
components of the paint therethrough. Preferably such The first coating 26 may be readily applied to the base
coating 26 comprises a sizing composition including a sheet employing a conventional size press of the type
starch and a binder water/solvent repellent. Either corn well known in the papermaking industry. The first coat
or potato starch have been found suitable for this appli- ing may be dried before the second coating is applied,
cation, with corn starch being preferred because of its 50 or if desired, the second coating may be applied to the
economic advantage. The binder water repellent (here- opposite surface of the base sheet before the product is
inafter referred to at times only as a "binder") may dried.
include any of the known polymeric binders employed The second coating for the base sheet of the present in papermaking in combination with starch, such bind- invention may be applied by any of several conveners including latices such as vinyl acetates, vinyl acryl- 55 tional coating processes and using conventional apparaics, styrene butadiene, or acetate acrylics. In any event, tus that is well-known in the paper industry. One suitthe preferred binder is resistive to degradation by the able apparatus is a short dwell blade coater available common solvents found in paints so that the coating is from a variety of suppliers including Beloit Corporanot materially degraded by the paint sprayed thereon tion. In the application of the coating using a blade and which flows therethrough into the absorptive reser- 60 coater apparatus, the base sheet is fed forwardly as by a voir of the present masking material. Further, the set of feed rolls to a station at which the coating compobinder preferably is compatible with the fibrous content sition is flowed onto the upper surface of the base sheet of the base sheet such that when applied to the surface and thereafter passed under a blade which serves to of the base sheet, the binder and starch further serve to spread the coating onto the surface in a coating of a bond at least those fibers adjacent the surface of the base 65 thickness that is established by the gap between the sheet to one another and/or to the binder itself to blade and the sheet surface. After application, the coatthereby prevent such fibers from becoming dislodged ing is dried and the product collected either in sheet or from the base sheet. Still further it has been found that web form. Preferably, one of the first and second coat