Patent Application
20120071308
This application includes material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent disclosure, as it appears in the Patent and Trademark Office files or records, but otherwise reserves all copyright rights whatsoever.
This document pertains to methods for making foam paint rollers of the type used for applying paint to walls and the like. More specifically, to new methods of making paint rollers having a foam exterior painting surface.
In the accompanying drawings forming a part of this specification, and in which like reference characters are employed to designate like parts throughout the same:
a is a cross sectional approximation of an exemplary cover material for use in the method of making foam paint rollers disclosed herein.
b is a cross sectional approximation of another exemplary cover material for use in the method of making foam paint rollers disclosed herein.
A paint roller, as is known in the art, is a generally cylindrical paint applicator usually having an open inner diameter that accepts insertion of a cage (also known as a cage frame) or other support to enable its use in painting. A paint roller can be formed by having a strip comprising a clickable foam circumscribed about a core in a helical fashion—that is as a general helix or cylindrical helix. To the extent that the foam circumscribed about the core has a thickness D, the diameter circumscribed by an inner surface of the foam is necessarily smaller than the diameter circumscribed by the outer surface of the foam. The depth D of the foam is equal to ½ of the difference in those diameters.
As an example, where a paint roller having a 1.5″ inner diameter of the core is manufactured using two core-forming strips having a 0.025″ thickness, and two layers of adhesive having a thickness of 0.020, and a cover material strip, the diameter at the point of contact between the cover material strip and the adhesive is approximately 1.590″. In such an embodiment, exemplary cover material strip, may be approximately 2.875″. The following table shows the approximate difference between the circumference at the inner surface of a cover material and at the outer surface of the cover material for several different exemplary cover material depths D:
Accordingly, it can be seen that with a cover material having a depth of just ½″, the difference in the circumference from the inner surface to its outer surface is more than 3″. In an typical 1.5″ paint roller (meaning a 1.5″ inner diameter) having a ½″ cover material, the 3″ difference represents almost 60% of the circumference the inner surface of the cover material. In other words, the circumference measured at the outer surface of a ½″ cover material is about 1.6× as much, or about 60% longer, than the circumference at the inner surface.
In another example, for a 1.5″ inner diameter paint roller having a core thickness of 0.075″ using a ¼″ cover material, the circumference measured at the outer surface of the cover material is about 6.519″, while the circumference at the inner surface is about 4.948″. Where the cover is ½″, the circumference measured at the outer surface of the cover material is about 8.090″, while the circumference at the inner surface is still about 5.948″.
For the purpose of this disclosure, the term trapezoid shall have its common meaning, includes having exactly one pair of parallel sides, thereby excluding from the definition of trapezoid parallelograms, e.g., the rhomboid, rhombus, rectangle and square.
a shows a cross sectional approximation of an exemplary cover material 5 for use in the method of making foam paint rollers disclosed herein. The cover material 5 is formed from a continuous strip of foam base 6. The foam base 6 comprises a clickable foam. The foam may consist substantially entirely of clickable polyurethane foam or clickable polyester foam, or may consist of any other suitable clickable foam material. In an embodiment the foam has sponge-like qualities that permit absorption and retention of paint on a paint roller, and ready application of paint to a surface. Plastic foams of the polyurethane class have been found to possess such sponge-like characteristics.
The cross section of the foam base 6 of the continuous strip of cover material 5 forms an isosceles trapezoid. The isosceles trapezoid has a depth D defining the thickness of the foam base 6, a first width W1 defining the width of a first surface or inner surface, and a second width W2 defining the width of a second surface or outer surface. The width of the inner surface W1 is smaller than the width of the outer surface W2.
By shaping the cross section of the foam base 6 of the cover material 5 in an isosceles trapezoid, the helically wrapped cover material 5 will not have substantial gaps between the helical winds of the cover material. The difference in the isosceles trapezoid widths, i.e., the width of the inner surface W1 and the width of the outer surface W2, is thus provided to make accommodation for the differing circumferences between the inner and outer surfaces. More specifically, the foam base 6 has the shape of a isosceles trapezoid with angles sufficient to reduce or eliminate gaps between the outer surface of successive helical winds on a finished paint roller.
In an embodiment, a backing 7 is secured to the inner surface of the foam base 6. The backing 7 may be secured to the foam base 6 using an adhesive (not shown.) The thickness (e.g., depth) of the backing 7 is generally insubstantial or small when compared to the depth D of the foam base 6. Accordingly, the backing 7 need not (but may) have a cross section forming an isosceles trapezoid. Where it is in the form of an isosceles trapezoid, it's longer width would be substantially the same as the width of the inner surface W1.
The backing 7 may add stability and/or reduce the stretchiness of the foam base 6. The backing 7 can be any suitable material such as, for example, scrim, fiberglass, polyester or polypropylene. Where the backing 7 is formed from polypropylene, the polypropylene can be extruded directly onto the foam base 6 and thus not require a separate adhesive to be bonded thereto.
In an embodiment, the outer surface of foam base 6 has an outer layer 8. In an embodiment, the outer layer 8 comprises a microfiber lamination. The outer layer 8 may be laminated to the foam base 6 by electrostatic bonding or any other suitable bonding method, including the use of liquid adhesives. The thickness (e.g., depth) of the outer layer 8 is generally insubstantial when compared to the depth D of the foam base 6. Accordingly, the outer layer 8 need not (but may) have a cross section forming an isosceles trapezoid. Where it is in the form of an isosceles trapezoid, it's shorter width would be substantially the same as the width of the outer surface W2.
Turning to
The cross section of the foam base 12 of the continuous strip of cover material 10 forms a trapezoid having one pair of parallel sides. One side of the trapezoid formed by the cross section cover material 10 is perpendicular to the parallel sides as shown by angle b, while the other side is not perpendicular to the parallel sides as shown by angle c. In an embodiment, angle c is in the range of between 45 degrees and 80 degrees. While many different angles c will yield good results, experimentation has revealed that on foam of between ¼ and ½″, angle c yields good results within the range of between about 55 and 65 degrees, and specifically at 61 degrees. The trapezoid has a depth D defining the thickness of the foam base 12, a first width W1 defining the width of a first surface or inner surface, and a second width W2 defining the width of a second surface or outer surface. The width of the inner surface W1 is smaller than the width of the outer surface W2.
When wrapped around a mandrel in the process of manufacturing a paint roller (as discussed in more detail below), the diameter of the inner surface of the foam base 12 is smaller than the diameter of the outer surface of the foam base 12.
As above, for example, where a paint roller having a 1.5″ inner diameter of the core is manufactured using two strips comprising of material having a 0.025″ thickness, and two layers of adhesive having a thickness of 0.020, and a cover material 10, the diameter at the point of contact between the cover material 10 and the adhesive is approximately 1.590″. In such an embodiment, W1 for exemplary cover material 10 is approximately 2.875″ wide. The foam can be any suitable thickness and angle c may be in the range of 45 to 80 degrees. In an exemplary embodiment where the foam is ½ inch and angle c is selected to be 61 degrees, W2 would be approximately 3.117″. A specific efficiency may arise in forming the foam base 12 because only one non-perpendicular cut is needed. Specifically, a foam strip of width W1+W2 can be cut and the specified angle, i.e., between 45 and 80 degrees, thus forming two separate strips bearing the same angular cut. For example, for the exemplary ½ inch foam cut at an angle of 61 degrees, a single cut can be made in a foam strip having a rectangular cross section measuring ½ inch by just less than 6″ (i.e., approximately 5.992 inches).
By shaping the cross section of the foam base 12 of the cover material 10 in a trapezoid as described above in connection with
In an embodiment, a backing 14 is secured to the inner surface of the foam base 12. The backing 14 may be secured to the foam base 6 using an adhesive (not shown.) The thickness (e.g., depth) of the backing 14 is generally insubstantial or small when compared to the depth D of the foam base 12. Accordingly, the backing 14 need not (but may) have a cross section forming a trapezoid. Where it is in the form of a trapezoid, it's longer width would be substantially the same as the width of the inner surface W1.
The backing 14 may add stability and/or reduce the stretchiness of the foam base 12. The backing 14 can be any suitable material such as, for example, scrim, fiberglass, polyester or polypropylene. Where the backing 14 is formed from polypropylene, the polypropylene can be extruded directly onto the foam base 12 and thus not require a separate adhesive to be bonded thereto.
In an embodiment, the outer surface of foam base 12 has an outer layer 16. In an embodiment, the outer layer 16 comprises a microfiber lamination. The outer layer 16 may be laminated to the foam base 12 by electrostatic bonding or any other suitable bonding method, including the use of liquid adhesives. The thickness (e.g., depth) of the outer layer 16 is generally insubstantial when compared to the depth D of the foam base 12. Accordingly, the outer layer 16 need not (but may) have a cross section forming an isosceles trapezoid. Where it is in the form of an isosceles trapezoid, it's shorter width would be substantially the same as the width of the outer surface W2.
Turning now to
Turning now to
With reference to
Where polypropylene is used in the strips 21, 32, 33 or adhesive 26, 36, either alone, or in combination with other thermoplastics or non-thermoplastic materials, including calcium carbonate, a nucleated polypropylene may be used.
