METHODS FOR MANUFACTURING A PAINT ROLLER AND COMPONENT PARTS THEREOF

[0001] This application claims priority to U.S. Patent Application No. 12/435 946 filed May 5 

2009 and to U.S. Patent Application No. 12/687 028 filed January 13  2010  the entire disclosures of which are incorporated herein by reference.

[0002] 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.

FIELD OF THE INVENTION

[0003] This invention pertains to methods and apparatus for making paint rollers of the type used for applying paint to walls and the like. More specifically  the invention pertains to methods and apparatus for making component parts for use in a process of making a paint roller  and methods and apparatus for making a paint roller.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] 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:

[0005] Figure 1 is a diagrammatic representation of a paint roller manufacturing apparatus that can be used in accordance with an embodiment of the present invention.

[0006] Figure 2 is a diagrammatic representation of an apparatus for forming a composite paint roller cover having a compound backing in accordance with an embodiment of the present invention.

[0007] Figure 3 is a diagrammatic representation of a multi-strip laminate paint roller manufacturing apparatus that can be used in accordance with an embodiment of the present invention.

[0008] Figure 4 is a diagrammatic representation of another paint roller manufacturing apparatus that can be used in accordance with an embodiment of the present invention.

[0009] Figure 5 is a diagrammatic representation of yet another paint roller manufacturing apparatus that can be used in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION AND EMBODIMENTS THEREOF

[0010] Figure 1 shows a diagrammatic representation of a paint roller manufacturing apparatus 100. A strip of material 145 comprising polypropylene is wrapped helically about a mandrel 140 held on a base 150. The mandrel may be cooled by a cooler (not shown). An adhesive 135 comprising polypropylene is applied to an outer surface of the strip 145 by applicator 130. A cover 125 is wrapped around the mandrel 150 over the first strip 145 and the adhesive 135. A helical belt 120 driven by rollers 120a  120b applies a compressive force on the cover material and advances the tubular assembly 115 down the mandrel 150. A flyaway saw 105 cuts the tubular assembly into lengths 110 that can be used  or cut and used to produce finished paint rollers.

Compound Adhesive

[0011] In an embodiment  the adhesive 135 is a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. In an embodiment the adhesive compound comprises at least 25% but not more than 45% calcium carbonate. In an embodiment the adhesive compound comprises at least 25% but not more than 33% calcium carbonate. In an embodiment  the calcium carbonate compounded with the polypropylene to form the compound adhesive 135 should be selected and/or processed to be relatively non-abrasive to the processing equipment.

[0012] In an embodiment  the applicator 130 applies a compound adhesive 135 formed by a twin screw extruder sufficient for compounding the calcium carbonate with polypropylene (not shown) from a supply of polypropylene resin in pellet form and a supply of calcium carbonate. When using a twin screw extruder  the calcium carbonate should be relatively non-abrasive to a extruder. [0013] In an embodiment  the calcium carbonate compounded with the polypropylene to form the compound adhesive 135 should be used in a relatively fine  powdered form. In an embodiment the calcium carbonate may have a median particle size of 3 micrometers or less. In an embodiment  the calcium carbonate compounded with the polypropylene to form the compound adhesive 135 may be surface treated.

[0014] The cost by weigh of calcium carbonate is expected to be lower than the cost by weigh of polypropylene  thus the use of a compounded adhesive 135 as described will reduce the cost of manufacturing paint rollers.

[0015] The adhesive 135 made from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight is expected to have higher thermal conductivity that an adhesive made from polypropylene alone. Accordingly  an adhesive 135 made from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight is expected to cool and set faster than an adhesive made from polypropylene alone. As a result of the higher thermal conductivity  when the apparatus 100 is operated using an adhesive 135 made from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight  it is expected that the apparatus will operate at higher overall throughput than it would when using an adhesive 135 comprising more than 95% polypropylene.

Compound Strip Material

[0016] In an embodiment  the strip 145 is made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. In an embodiment the strip 145 comprises at least 25% but not more than 45% calcium carbonate. In an embodiment the strip 145 comprises at least 25% but not more than 33% calcium carbonate.

[0017] In an embodiment  the calcium carbonate compounded with the polypropylene to form the strip 145 should be a relatively fine  powdered form of calcium carbonate. In an embodiment the calcium carbonate compounded with the polypropylene to form the strip 145 should have a median particle size of 3 micrometers or less. In an embodiment  the calcium carbonate compounded with the polypropylene to form the strip 145 may be surface treated.

[0018] The cost by weigh of calcium carbonate is expected to be lower than the cost by weigh of polypropylene  thus the use of a strip 135 made from a compound of polypropylene and calcium carbonate will reduce the cost of manufacturing paint rollers made therewith.

[0019] The strip 145 made from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight is expected to have higher thermal conductivity that an adhesive made from polypropylene alone. Because of the higher thermal conductivity using a strip 145 made from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight  rather than a strip 145 made from more than 95% polypropylene  it is anticipated that the adhesive 135 will set faster  and thus  apparatus 100 will operate at higher overall throughput than it would when using a strip 145 comprising more than 95% polypropylene.

Cover Material

[0020] In an embodiment  the cover 125 has a fabric backing and a pile outer surface such as knitted or woven cover materials; such a fabric backing of the cover 125 comprises interstitial pores into which adhesive 135 may flow  especially when compressed by the belt 120. In an embodiment  the cover is made from a micro fiber material; such a micro fiber cover 125 also comprises interstitial pores into which adhesive 135 may flow  especially when compressed by the belt 120.

[0021] In an embodiment  the cover 125 has a pile or micro fiber outer surface and a smooth or uniformly imprinted backing formed from polypropylene.

[0022] In an embodiment  the cover 125 has a pile or microfiber outer surface and a smooth or uniformly imprinted backing formed from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. In an embodiment the cover 125 comprises at least 25% but not more than 45% calcium carbonate. In an embodiment the cover 125 comprises at least 25% but not more than 33% calcium carbonate.

[0023] In an embodiment  the calcium carbonate compounded with the polypropylene to form the backing of the cover 125 should be a relatively fine  powdered form of calcium carbonate. In an embodiment the calcium carbonate compounded with the polypropylene to form the backing of the cover 125 should have a median particle size of 3 micrometers or less. In an embodiment  the calcium carbonate compounded with the polypropylene to form the backing of the cover 125 may be surface treated.

[0024] The cost by weigh of calcium carbonate is expected to be lower than the cost by weigh of polypropylene  thus the use of the backing of the cover 125 made from a compound of polypropylene and calcium carbonate will reduce the cost of manufacturing paint rollers made therewith.

[0025] The backing of the cover 125 made from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight is expected to have higher thermal conductivity that an adhesive made from polypropylene alone. Because of the higher thermal conductivity using a cover 125 having a backing made from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight  rather than a backing made from more than 95% polypropylene  it is anticipated that the adhesive 135 will set faster  and thus  apparatus 100 will operate at higher overall throughput than it would when using a cover 125 having a backing comprising more than 95% polypropylene.

Use Of Compounded Materials

[0026] Apparatus 100 may be operated according to the present invention using an adhesive 135 made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight; using a strip 145 made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight; and/or using a cover 250 having a backing made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. When more than one component is made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight  the percentage of calcium carbonate used in the compound forming the adhesive 135  the strip 145 and the cover 250 backing may be the same  or may differ from one-another.

[0027] When compounding of polypropylene and calcium carbonate in any compound of between 5% and 50% calcium carbonate by weight  the calcium carbonate is not expected to melt. As discussed above  the resulting compounds are expected to have higher thermal conductivity. Variation in the amount of calcium carbonate are within the scope of the invention  and thus  it will be apparent to one of skill in the art that to some degree thermal conductivity can be controlled  or a desired thermal conductivity or range of thermal conductivity can be achieved by varying the percentage of calcium carbonate in the compound.

[0028] The compounds of polypropylene and calcium carbonate used in the adhesive 135  strip 145 and/or cover 125 are expected to have achieve other characteristics that  when compared to using polypropylene alone  are expected to include increased stiffness. Increased stiffness may give a paint roller a firmer or stiffer feel  which may improve its performance as a paint roller. Moreover  in many cases  stiffer or firmer paint rollers are sold at a higher price. It will be apparent to one of skill in the art that to some degree  stiffness can be controlled  or a desired stiffness or range of stiffness can be achieved by varying the percentage of calcium carbonate in the compound. [0029] Figure 2 shows an apparatus 200 for forming the composite paint roller cover 250 having a compound backing. The roller 220 is urged toward the frame 230 by a spring  by gravity or by other means that will be apparent to persons skilled in the art. A layer of compound adhesive 210 is dispensed by an applicator 205 onto a roller 220  and runs between the roller 220 and a frame 230  such as a tenter frame  or between the roller 220 and another roller (not shown). The layer of compound adhesive 210 dispensed onto roller 220 may be between 0.010" and 0.020". In an embodiment  the compound adhesive 210 is a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. In an embodiment the adhesive compound comprises at least 25% but not more than 45% calcium carbonate. In an embodiment the adhesive compound comprises at least 25% but not more than 33% calcium carbonate. The calcium carbonate should be relatively non-abrasive to the processing machinery.

[0030] The cover material 215 is advanced along the frame 205 with its pile side down  and moved beneath the roller 220. The cover material 215 may have a pile side and a fabric backing - the fabric backing being porous and having interstitial spaces sufficient to permit penetration of the compound adhesive 210. As the cover material 215 and the layer of compound adhesive 210 pass between the roller 220 and the surface of the frame 230 they are urged together. The roller-side of the compound adhesive 210 may be smoothed or uniformly imprinted (e.g.  embossed) by the roller 220 as it passed underneath  thus forming a uniform or smooth adhesive layer surface 225. [0031] In an embodiment  the roller 220 applies a compressive force to urge the compound adhesive 210 towards the cover material 215. In an embodiment  the compressive force is sufficient to force the compound adhesive 210 into the interstitial spaces within the fabric backing of the cover material 215. The resulting composite sheet material 235 may be cut by a cutter 240 to trim away any excess materials  and thus to form the compound composite cover material 250 with a non-porous backing.

[0032] In an embodiment  the roller 220 may be heated or cooled.

[0033] In an embodiment  the apparatus comprises an applicator 205 that applies a compound adhesive 210 formed by a twin screw extruder sufficient for compounding calcium carbonate with polypropylene (not shown) from a supply of polypropylene resin in pellet form and a supply of calcium carbonate. The calcium carbonate should be relatively non-abrasive to the twin screw extruder.

[0034] The positioning and angular orientation of the applicator 205 may be varied. In an embodiment  the applicator is angled between 30 degrees and 60 degrees from vertical and positioned within inches of the middle of the roller 220. In another embodiment the applicator 205 is within 30 degrees (+/-) of vertical  and is positioned to dispense adhesive such that the adhesive layer 210 first makes contact on the upper half of the roller 220. In yet another embodiment  the applicator 205 is within 30 degrees (+/-) of horizontal and is positioned to dispense adhesive such that the adhesive layer 210 first makes contact on the lower half of the roller 220. Variations in the angular orientation of the applicator 205  and its distance from and orientation around the roller are within the scope of the invention  and will be apparent to one skilled in the art. [0035] Figure 3 shows a paint roller manufacturing apparatus 300. A strip of material 345 comprising polypropylene is wrapped helically about a mandrel 340 held on a base 350. The mandrel may be cooled by a cooler (not shown). A second strip of material 348 comprising polypropylene is wrapped helically about the first strip 345. An adhesive 335 comprising polypropylene is applied to an outer surface of the strips 345  348 by applicator 330. A cover 325 is also helically wrapped around the mandrel 350 over the strips 345  348 and the adhesive 335. A helical belt 320 driven by rollers 320a  320b applies a compressive force on the cover material and advances the tubular assembly 310 down the mandrel 350. A flyaway saw 305 may cut the tubular assembly 310 into lengths (not shown) that can be used  or further cut and used to produce finished paint rollers.

[0036] In an embodiment  the applicator 330 applies a compound adhesive 335 formed by a twin screw extruder sufficient for compounding the calcium carbonate with polypropylene (not shown) from a supply of polypropylene resin in pellet form and a supply of calcium carbonate. When using a twin screw extruder  the calcium carbonate should be relatively non-abrasive to a extruder. [0037] Apparatus 300 may be operated according to the present invention using an adhesive 335 made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight; using a strip 345 made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight; using a second strip 348 made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight; and/or using a cover 325 having a backing made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. When more than one component is made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight  the percentage of calcium carbonate used in the compound forming the adhesive 335  the strip 345  the second strip 348 and the cover 325 backing may be the same  or may differ from one-another.

[0038] Variation in the amount of calcium carbonate are within the scope of the invention  and thus  it will be apparent to one of skill in the art that to some degree thermal conductivity can be controlled  or a desired thermal conductivity or range of thermal conductivity can be achieved by varying the percentage of calcium carbonate in one or more of the compounds. It will be apparent to one of skill in the art that to some degree  stiffness can be controlled  or a desired stiffness or range of stiffness can be achieved by varying the percentage of calcium carbonate in these compounds as well.

[0039] Figure 4 shows a paint roller manufacturing apparatus 400. A strip of material 448 comprising polypropylene is wrapped helically about a mandrel 440 held on a base 450. The mandrel may be cooled by a cooler (not shown). A second strip of material 445 comprising polypropylene is wrapped helically about the first strip 448. The heaters 460  455 which may employ heating elements or heat by open flame  heat the outer surface (vis-a-vis the wrapping about the mandrel) of strips 448  445 respectively. The heat produced by the heaters 460 is sufficient to cause the outer surface of the strips 448  445 to become tacky  or to liquefy  or to become molten. (Although shown diagrammatically at a distance from the mandrel  in an embodiment  the heaters 460  455 should be placed as close as practicable to the point where the strips 448  445 contact the mandrel.) A cover 415 is also helically wrapped around the mandrel 440 over the outer surface of the second strip 445. A helical belt drive 420 applies an inwardly compressive force on the cover material 415 and advances the assembly down the mandrel 440. A flyaway saw 405 may cut the assembly into lengths (not shown) that can be used  or further cut and used to produce finished paint rollers.

[0040] Apparatus 400 may be operated according to the present invention using a strip 448 made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight; using a second strip 445 made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight; and/or using a cover 415 having a backing made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. When more than one component is made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight  the percentage of calcium carbonate used in the compound forming the strips 448  445 and the cover 415 backing may be the same  or may differ from one-another.

[0041] Variation in the amount of calcium carbonate are within the scope of the invention  and thus  it will be apparent to one of skill in the art that to some degree thermal conductivity can be controlled  or a desired thermal conductivity or range of thermal conductivity can be achieved by varying the percentage of calcium carbonate in one or more of the compounds. It will be apparent to one of skill in the art that to some degree  stiffness can be controlled  or a desired stiffness or range of stiffness can be achieved by varying the percentage of calcium carbonate in these compounds as well.

[0042] Figure 5 shows an apparatus 500 suitable for making paint rollers with a preformed core. The apparatus 500 comprises a rotating mandrel 510  a carriage 560 running on a stationary track 570 and supporting a cover material guide 550  and a heater 530. A preformed core 540 comprising polypropylene is placed about the mandrel 510. The heater 530 is activated  thereby heat softening the outer surface of the preformed core in an amount sufficient to bond to the backing of the cover 520. The cover 520 is wrapped helically about the core by the rotation of the mandrel and the movement of the carriage 560. The rotation of the mandrel 510 and the movement of the carriage 560 are such that the cover 520 is wrapped about substantially all of the preformed core 540. [0043] Apparatus 500 may be operated according to the present invention using a preformed core 540 made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight; and/or using a cover 520 having a backing made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. When more than one component is made of a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight  the percentage of calcium carbonate used in the compound forming the core 540 and the cover 520 backing may be the same  or may differ from one-another.

[0044] Variation in the amount of calcium carbonate are within the scope of the invention  and thus  it will be apparent to one of skill in the art that to some degree thermal conductivity can be controlled  or a desired thermal conductivity or range of thermal conductivity can be achieved by varying the percentage of calcium carbonate in one or more of the compounds. It will be apparent to one of skill in the art that to some degree  stiffness can be controlled  or a desired stiffness or range of stiffness can be achieved by varying the percentage of calcium carbonate in these compounds as well.

[0045] It is possible  without departing from the invention  to use a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight in lieu of polypropylene in making paint rollers. In light of this disclosure  other methods for the manufacture of the same will be apparent to persons of skill in the art.

[0046] Benefits of certain embodiments of the instant invention include: control of thermal conductivity in the component materials leading to faster throughput and/or faster set times; and control of material characteristics such as stiffness for manufacture of harder  more expensive paint rollers.

[0047] The above embodiments and preferences are illustrative of the present invention. It is neither necessary  nor intended for this patent to outline or define every possible combination or embodiment. The inventor has disclosed sufficient information to permit one skilled in the art to practice at least one embodiment of the invention  and has disclosed the ways the inventor now believes are the best ways to practice the invention. The above description and drawings are merely illustrative of the present invention and that changes in components  structure and procedure are possible without departing from the scope of the present invention as defined in the following claims.

ILLUSTRATIVE EMBODIMENTS SHOWN IN THE FIGURES

[0048] In one embodiment  the invention is a method of making a paint roller. A strip of material is helically wound around a mandrel so as to form a helically wound strip. The strip is formed from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. The wound strip is advanced along the mandrel. A layer of adhesive is applied onto an outer surface of the wound strip. A strip of cover material then is helically wrapped about the wound strip and over the layer of adhesive  thereby bonding the strip of cover material to the wound strip for forming the paint roller.

[0049] In another embodiment  the invention is method of making a paint roller. A strip of material is helically wound around a mandrel so as to form a helically wound strip. The wound strip is advanced along the mandrel. An adhesive is compounded from polypropylene and calcium carbonate. The compound comprises between 5% and 50% calcium carbonate by weight. The layer of adhesive is applied onto an outer surface of the wound strip. A strip of cover material then is helically wrapped about the wound strip and over the layer of adhesive  thereby bonding the strip of cover material to the wound strip for forming the paint roller.

[0050] In another embodiment  the invention is method of making a paint roller. A strip of material helically wound around a mandrel so as to form a helically wound strip. The strip is formed from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. The wound strip is advanced along the mandrel. An adhesive is compounded from polypropylene and calcium carbonate. The compound comprises between 5% and 50% calcium carbonate by weight. The layer of adhesive is applied onto an outer surface of the wound strip. A strip of cover material then is helically wrapped about the wound strip and over the layer of adhesive  thereby bonding the strip of cover material to the wound strip for forming the paint roller.

[005I] In another embodiment  the invention is a method for continuously producing a multi-strip laminate paint roller. An inner strip and an outer strip of material is helically advanced about a mandrel in offset relation. At least one of the strips is formed from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. A layer of adhesive is applied between the two strips and on the outer surface of the outer strip. Prior to permitting the layer of liquid polypropylene to harden and set  a cover is wrapped around the outer strip and a compressing force is applied upon the cover urging the cover and the two strips toward the mandrel  thereby creating the continuous laminated paint roller.

[0052] In another embodiment  the invention is a method for continuously producing a multi-strip laminate paint roller. An inner strip and an outer strip of material is helically advanced about a mandrel in offset relation. An adhesive material is compounded from polypropylene and calcium carbonate  the compound comprising between 5% and 50% calcium carbonate by weight. The adhesive material is applied between the two strips and on the outer surface of the outer strip. Prior to permitting the adhesive material to harden and set  a cover is wrapped around the outer strip and a compressing force is applied upon the cover urging the cover and the two strips toward the mandrel  thereby creating the continuous laminated paint roller.

[0053] In another embodiment  the invention is a method for continuously producing a multi-strip laminate paint roller. An inner strip and an outer strip of material is helically advanced about a mandrel in offset relation  at least one of the strips being formed from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. An adhesive material is compounded from polypropylene and calcium carbonate. The compound comprises between 5% and 50% calcium carbonate by weight. The adhesive material is applied between the two strips and on the outer surface of the outer strip. Prior to permitting the layer of liquid polypropylene to harden and set  a cover is wrapped around the outer strip and a compressing force is applied upon the cover urging the cover and the two strips toward the mandrel  thereby creating the continuous laminated paint roller.

[0054] In another embodiment  the invention is a method of making a composite cover material. A first width of pile material is advanced. The pile material has a pile side and a fabric backing  wherein the fabric backing is porous  having interstitial spaces or gaps. An adhesive is compounded from polypropylene and calcium carbonate. The compound comprises between 5% and 50% calcium carbonate by weight. A layer of the adhesive is applied to the fabric backing of the pile material. The adhesive layer is allowed to set to form a composite sheet material having a pile side and a non-porous backing. The composite sheet material is longitudinally cut to form one or more strips of composite cover material in a second width. The formed composite cover material has an inner surface and an outer surface  the outer surface comprising a pile  and the inner surface comprising a non-porous layer bonded thereto.

[0055] In another embodiment  the invention is a method of making a paint roller having one or more materials making up its core. An adhesive material is compounded from polypropylene and calcium carbonate. The compound comprises between 5% and 50% calcium carbonate by weight. The adhesive material is applied between a cover material and one or more materials making up the paint roller core. The adhesive material is permitted to harden and set  thereby creating the paint roller.

[0056] In another embodiment  the invention is a method of making a laminated paint roller. A strip comprising polypropylene is helically wound around a mandrel so as to form a helically wound strip  the strip having an outer surface. The wound strip is helically advanced along the mandrel. A layer of adhesive comprising polypropylene is applied onto the outer surface of the wound strip. A strip of composite cover material is then wrapped about the wound strip and over the layer of adhesive. The composite cover material is formed by method comprising the following steps. A width of porous pile material is provided having a pile side and an fabric underside. The width of pile material is advanced with the fabric underside facing up. A backing layer is compounded from polypropylene and calcium carbonate  the compound comprising between 5% and 50% calcium carbonate by weight. The backing layer is applied on the fabric underside of the advancing width of pile material so that the layer has one side that is in contact with the fabric underside of the advancing material and an other side that is not in contact with the advancing pile material  the layer being in molten form when it is applied. A compressive force is applied to the other side of the layer before the layer hardens and sets  to smooth the other side of the layer of polypropylene  and to urge the layer and the fabric underside of the pile material together  thereby forming a composite material having a smooth or uniformly imprinted non-porous side and a pile side  and wherein the pile is held fast on the composite material. The width of composite material is cut into a strip once the backing layer is no longer in molten form  thereby forming a composite cover material having an inner surface comprising a smooth or uniformly imprinted non-porous polypropylene side and a pile side. The composite cover material produced by the method described above is then used to form a laminated pain roller. A compressive force is applied from without the composite cover material to urge the composite cover material  the layer of adhesive and strip of non-porous polypropylene material together  thereby laminating the smooth inner surface of the composite cover material to the outer surface of the non-porous polypropylene strip.

[0057] In another embodiment  the invention is a method of making a laminated paint roller. An inner strip of thermoplastic material is helically around a mandrel so as to form a helically wound inner strip  the inner strip having an outer surface. A second strip of thermoplastic material is helically wound around a mandrel in offset relation to the inner strip  so as to form a helically wound second strip  the second strip having an inner surface and an outer surface. The wound inner and second strips are advanced along the mandrel. An adhesive is compounded from polypropylene and calcium carbonate  the compound comprising between 5% and 50% calcium carbonate by weight. A layer of the adhesive is applied onto the outer surface of the wound inner strip and the outer surface of the wound second strip. A strip of composite cover material is then wrapped about the wound second strip and over the layer of adhesive applied to the wound second strip. The composite cover material has an inner surface and an outer surface  the outer surface comprising a pile fabric  and the inner surface comprising a smooth generally non-porous backing comprising polypropylene. A compressive force is then applied from without the composite cover material to urge the composite cover material  the layer of adhesive and inner and second strips together  thereby laminating the inner surface of the composite cover material to the outer surface of the second strip and laminating the inner surface of the second strip to the outer surface of the inner strip.

[0058] In another embodiment  the invention is a method for continuously producing a multi-strip laminate paint roller. An inner strip and an outer strip of material is helically advanced about a mandrel in offset relation. At least one of the strips is formed from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. The inner strip and the outer strip have an outer surface facing away from the mandrel. The outer surface of the inner and outer strips is heated to cause a layer of the outer surface of the strips to become liquefied. Prior to permitting the liquefied layers to harden and set  a cover around is wrapped around the outer strip and a compressing force is applied upon the cover urging the cover and the two strips toward the mandrel  thereby creating the continuous laminated paint roller.

[0059] In another embodiment  the invention is a cold core method of making a paint roller from a cold  hard  preformed hollow core of thermoplastic material of a predetermined length in which the cold hard hollow core and its associated cover are forged together to form a single unitary body. A cold hard hollow core is provided. The cold hard hollow core is formed from a compound of polypropylene and calcium carbonate having between 5% and 50% calcium carbonate by weight. A mandrel having an external diameter is provided. The mandrel slidably receives and makes contact with the cold hard hollow core. The cold hard hollow core is rotated. The exterior surface of the cold hard hollow thermoplastic rotating core is heated  by application of a single source of heat  to a temperature high enough to cause subsequently applied cover to adhere to said exterior surface. A cover is then to the heated exterior surface of the cold hard hollow thermoplastic core  thereby bonding the cover to the heated exterior surface thereof  and forming a paint roller.

FURTHER OBSERVATIONS

[0060] In experimenting with various ratios and materials  several further observations have been made  and the inventions of such further observations and additional embodiments are hereinafter presented  in addition to those discussed above. Polypropylene identified as 3462-US  4920WZ-US and 6823MZ-US from Total Petrochemicals of Houston  Texas was used for experimentation. MFI reported herein for the polypropylene resin is as understood from Total Petrochemicals literature.

Calcium Carbonate

[0061] The use of non-refined calcium carbonate in combination with polypropylene  e.g.  calcium carbonate that has not been surface treated  adds strength to the resulting paint roller product when compared to a combination of refined calcium carbonate in combination with polypropylene. Thus  in an embodiment  the calcium carbonate compounded with the polypropylene to form the compound adhesive 135 (Fig. 1) may be a non-refined calcium carbonate. In an embodiment  the non-refined calcium carbonate is used in a relatively fine  powdered form. In an embodiment the calcium carbonate may have a median particle size of 3 micrometers or less.

[0062] In an embodiment  a twin screw extruder (not shown) may be used to compound non-refined calcium carbonate and polypropylene together to form the compound adhesive 135. The twin screw extruder may accept a supply of polypropylene resin in pellet form and a separate supply of calcium carbonate.

Ratio and Composition of Compound Adhesive

[0063] Experimentation was performed concerning the ratio of calcium carbonate - a ratio earlier thought to be preferred between 5% and 50% calcium carbonate by weight. As discussed above  the cost by weigh of calcium carbonate is generally lower than the cost by weigh of polypropylene  thus  the raw material cost of a compounded adhesive will be reduced as the ratio of calcium carbonate rises. Typically  today  the cost of polypropylene resin may be $0.64 per pound  while the cost of appropriate calcium carbonate may be $0.09 per pound. Using those typical costs  the raw materials required to make a compounded adhesive comprising 5% calcium carbonate by weight is approximately $0.6125 per pound; the raw materials required to make a compounded adhesive comprising 50% calcium carbonate by weight is approximately $0 365 per pound; and the raw materials required to make a compounded adhesive comprising 60% calcium carbonate by weight is approximately $0.31 per pound. While the process of compounding the materials itself has a cost  the large factors in savings are: (i) the disparity between the cost of the polypropylene resin and the calcium carbonate; and (ii) the percentages of calcium carbonate that can be used. [0064] Experimentation was performed and acceptable results were found using a compounded adhesive 135 (see Figure 1) made from polypropylene resin with approximately 60% calcium carbonate by weight. In an embodiment  adhesive 135 is a compound of polypropylene and calcium carbonate having between 50% and 66% calcium carbonate by weight. In an embodiment an adhesive compound 135 comprises at least 55% but not more than 65% calcium carbonate. In an embodiment an adhesive compound 135 is a compound of polypropylene and calcium carbonate having approximately 60% calcium carbonate by weight.

[0065] Experimentation was performed and acceptable results were found using a compounded adhesive 335 (see Figure 3) made from polypropylene resin with approximately 56% calcium carbonate by weight. In an embodiment  an adhesive 335 is a compound of polypropylene and calcium carbonate having at least 50%  but less than 60% calcium carbonate by weight. In an embodiment an adhesive compound 335 is a compound of polypropylene and calcium carbonate having approximately 56% calcium carbonate by weight.

[0066] Polypropylene resin 6823MZ-US in pellet form used to create adhesive first used for the further testing had a melt flow index ("MFI") of approximately 32. For the further testing  the 32 MFI resin was compounded with a 60% mixture of calcium carbonate to form the compound adhesive 135. The resulting compound adhesive 135 had an MFI of approximately 14.4. Although the compound adhesive could be extruded through applicator 130  the low MFI appeared to cause the extruded to struggle  and the extruded material was highly viscous. The paint rollers resulting from the foregoing compound appeared to be substantially stronger when non-refined calcium carbonate was used rather than surface treated calcium carbonate. When the same 32 MFI resin was compounded with the same 60% mixture of calcium carbonate to form the compound adhesive 335 (see Fig. 3)  it appeared that the MFI of the compound adhesive 335 was too high to permit a smooth flow from the applicator 330.

[0067] Polypropylene resin 4920 WZ-US was tried. Polypropylene resin 4920 WZ-US in pellet form used to create adhesive next used for the further testing had a melt flow index ("MFI") of approximately 105. For the next test  the 105 MFI resin was compounded with a 60% mixture of calcium carbonate to form the compound adhesive 135. The resulting compound adhesive 135 had an MFI of approximately 28.8. Using the 105 MFI resin  the compound adhesive 135 was extruded through applicator 130 without substantial stress on the extruder as the compounded adhesive 135 was of appropriate viscosity for use with the applicator 130. Again  the paint rollers resulting from the foregoing compound was substantially stronger when non-refined calcium carbonate was used rather than surface treated calcium carbonate. When the same 105 MFI resin was compounded with the same 60% mixture of calcium carbonate to form the compound adhesive 335 (see Fig. 3)  it again appeared that the MFI was too high to permit a smooth flow from the applicator 330. [0068] As the vendor did not have polypropylene resin available with an MFI higher than 105  for the following test  the 105 MFI resin was compounded with a 56% mixture of calcium carbonate to form the compound adhesive 335. The resulting compound adhesive 335 had an MFI of approximately 32. Using the 105 MFI resin  the compound adhesive 335 was extruded through applicator 330 without substantial stress on the extruder as the compounded adhesive 335 was of appropriate viscosity for use with the applicator 330. As before  the paint rollers resulting from the foregoing compound appeared to be substantially stronger when non-refined calcium carbonate was used rather than surface treated calcium carbonate. As an alternative to reducing ratio of calcium carbonate to 56%  the use of a polypropylene resin having a higher MFI  such as an MFI of approximately 120  with 60% calcium carbonate would have achieved acceptable results.

Composition of Strips

[0069] As with composite adhesives 135  335  strip material 145  345  348  445  448 can be manufactured using a compound of polypropylene and calcium carbonate. In an embodiment  a strip 145  345  348  445  448 is cut lengthwise from a sheet material (not shown) that is manufactured using a compound of polypropylene and calcium carbonate. In an embodiment  the thickness of the sheet material is determined by successive rollers. Because rollers are used to control thickness  the MFI of the polypropylene / calcium carbonate compound may be substantially lower than that of the MFI required for use a compound adhesives 135  335. In an embodiment  4.1 MFI polypropylene resin 3462-US is compounded with approximate 60% by weight of calcium carbonate. The resulting polypropylene / calcium carbonate compound  having an MFI of approximately 2  can be run through successive rollers to reach a desired thickness. Almost any desired strip thickness can be attained. In an embodiment  a sheet of polypropylene / calcium carbonate compound material having thickness of approximately 10 mil  15 mil  20 mil or 25 mil can be cut longitudinally into one or more strip 145  345  348  445  448.

[0070] In an embodiment  the calcium carbonate used in manufacturing sheet material which can be cut into strips is non-refined calcium carbonate.

Composite Cover Material

[0071] Returning to Figure 2  an apparatus 200 is shown for forming the composite paint roller cover 250 having a compound backing. A layer of compound adhesive 210 is dispensed by an applicator 205. The layer of compound adhesive 210 dispensed may be dispensed onto roller 220 or directly onto cover material 215. In an embodiment  the layer of compound adhesive 210 is between 0.010" and 0.020". In an embodiment  the compound adhesive 210 is a compound of polypropylene and calcium carbonate having at least 50%  and not more than 66% calcium carbonate by weight. The MFI of polypropylene / calcium carbonate compound the may be varied by changing using a polypropylene resin having a higher or lower MFI  as well as by varying the ratio of calcium carbonate. Using polypropylene resin having a higher MFI will cause the polypropylene / calcium carbonate compound to have a higher MFI when using the same ratio of calcium carbonate. Similarly  the MFI of the resulting compound can be lowered by reducing the percentage of calcium carbonate used in the polypropylene / calcium carbonate compound. In view of the foregoing  it will be apparent to one of skill in the art how to the MFI of polypropylene / calcium carbonate compound layer 210 can be varied so as to permit it to be dispensed appropriately by an applicator 205.

[0072] In an embodiment  the cover material 215 has a pile side and a fabric backing - the fabric backing being porous and having interstitial spaces sufficient to permit penetration of compound adhesive 210. In an embodiment  the compound adhesive 210 has an MFI higher than 2. In an embodiment  the compound adhesive 210 has an MFI between 14 and 105. In an embodiment  an MFI of in or around the mid 70 ""s is desired to permit the compound 210 to properly permeate the fabric backing of the cover material 215. To obtain compound adhesive 210 having an MFI in or around the mid-70 ""s 105 MFI polypropylene resin is compounded with 25% calcium carbonate by weight.

[0073] In an embodiment  the apparatus comprises an applicator 205 that applies a compound adhesive 210 formed by a twin screw extruder sufficient for compounding calcium carbonate with polypropylene (not shown) from a supply of polypropylene resin in pellet form and a supply of calcium carbonate to produce a compound that includes at least 50% calcium carbonate by weight.

Illustrative Paint Rollers

[0074] Returning to Figure 1  in an embodiment  a strip 145 comprises polypropylene  and has a thickness of between 10 mil and 40 mil. In an embodiment  the strip 145 is approximately 10 mil  15 mil  20 mil or 25 mil thick. In an embodiment  the strip 145 may be of another suitable thickness. [0075] In an embodiment  the strip 145 is made from a polypropylene / calcium carbonate compound comprising at least 50%  but not more than 66% calcium carbonate by weight. In an embodiment  the strip 145 is made from a polypropylene / calcium carbonate compound comprising approximately 60% calcium carbonate by weight. The strip 145 made from a polypropylene / calcium carbonate compound comprising at least 50% calcium carbonate by weight  is expected to have higher thermal conductivity than a strip made from polypropylene alone  or than a strip made from a polypropylene / calcium carbonate compound comprising less than 50% calcium carbonate by weight. Because of the higher thermal conductivity using a strip 145 made from a compound of polypropylene and calcium carbonate comprising at least 50% calcium carbonate by weight  it is anticipated that the adhesive 135 will set faster  and thus  apparatus 100 will operate at higher overall throughput than it would when using a strip 145 comprising more than 50% polypropylene.

[0076] In an embodiment  adhesive 135 comprises polypropylene  and is applied in a layer having a thickness of between 10 mil and 40 mil. In an embodiment  the layer of adhesive 135 is approximately 10 mil  15 mil  20 mil or 25 mil thick. In an embodiment  the layer of adhesive 135 is another suitable thickness.

[0077] In an embodiment  the adhesive 135 is made from a polypropylene / calcium carbonate compound comprising at least 50%  but not more than 66% calcium carbonate by weight. In an embodiment  the adhesive 135 is made from a polypropylene / calcium carbonate compound comprising approximately 60% calcium carbonate by weight. The adhesive 135 made from a polypropylene / calcium carbonate compound comprising at least 50% calcium carbonate by weight  is expected to have higher thermal conductivity than an adhesive made from polypropylene alone  or than an adhesive made from a polypropylene / calcium carbonate compound comprising less than 50% calcium carbonate by weight. Because of the higher thermal conductivity using an adhesive 135 made from a compound of polypropylene and calcium carbonate comprising at least 50% calcium carbonate by weight  it is anticipated that it will set faster  and thus  apparatus 100 will operate at higher overall throughput than it would when using an adhesive 135 comprising more than 50% polypropylene.

[0078] In an embodiment  the backing of composite cover 125 comprises polypropylene  and the backing comprising polypropylene is in a layer having a thickness of between 10 mil and 40 mil. In an embodiment  the backing layer of the composite cover material 125 is approximately 10 mil  15 mil  20 mil or 25 mil thick. In an embodiment  the backing of the composite cover material 125 is another suitable thickness.

[0079] In an embodiment  the backing of the composite cover material 125 is formed from a polypropylene / calcium carbonate compound comprising at least 50%  but not more than 66% calcium carbonate by weight. In an embodiment  the backing of the composite cover material 125 is formed from a polypropylene / calcium carbonate compound comprising approximately 60% calcium carbonate by weight. The backing of the composite cover material 125 formed from a polypropylene / calcium carbonate compound comprising at least 50% calcium carbonate by weight  is expected to have higher thermal conductivity than a backing made from polypropylene alone  or than a backing made from a polypropylene / calcium carbonate compound comprising less than 50% calcium carbonate by weight. Because of the higher thermal conductivity using a composite cover material 125 having a backing formed from a compound of polypropylene and calcium carbonate comprising at least 50% calcium carbonate by weight  it is anticipated that the adhesive 135 will set faster  and thus  apparatus 100 will operate at higher overall throughput than it would when using a composite cover material 125 having a backing formed from a compound of polypropylene and calcium carbonate comprising more than 50% polypropylene.

[0080] The following table presents illustrative paint rollers that will be used in the discussion below.

[0081] The following table presents illustrative paint rollers that can be formed using the invention disclosed herein. The "Cover" column refers to the cover material 125 used  the "Adhesive" column refers to the adhesive 135 used and the "Strip" column refers to the strip 145 used in the example. For each column  the entry reflects the thickness in mil  and the percentage of calcium carbonate (by weight) compounded with polypropylene to form the component. The thickness in mil for the "Cover" column reflects the thickness of the layer 135 used to form the composite cover material 125 - the "Cover" column entries showing a thickness of 0 reflect the use of a cover material rather than a composite cover material.

[0082] Example Al and Bl  each make paint rollers of the same thickness  however  the characteristics of the paint roller Bl are substantially improved when compared to those of Al. The Bl paint roller feels firmer and is of higher quality than the Al paint roller. Moreover  the 30 mil thick Bl paint roller uses only 40% of the polypropylene used to manufacture the Al paint roller (excluding any polypropylene in the cover material).

[0083] Similarly  Example A2 and B2  each make paint rollers of the same thickness  however  the characteristics of the paint roller B2 are substantially improved when compared to those of A2. The B2 paint roller feels firmer and is of higher quality than the A2 paint roller. Moreover  the 40 mil thick B2 paint roller uses only 55% of the polypropylene used to make the A2 paint roller (excluding any polypropylene in the cover material). In fact  the Bl paint roller compares favorably to the A2 paint roller while using only as much as 30% as much polypropylene.

[0084] Notably the B3 paint roller is the most superior of all of these example rollers  and it uses less than half as much polypropylene as the A2 roller  and just over half as much as the Al roller. [0085] Many other variations are possible. For example  it is not necessary to use both a compound adhesive and a strip formed from compounding polypropylene and calcium carbonate. In addition  it is not necessary to use a composite cover material formed from a compound of polypropylene / calcium carbonate. The use of (i) a compound strip  (ii) compound adhesive or (ii) composite cover material formed from a compound of polypropylene / calcium carbonate  will each produce a stronger roller  with less polypropylene  than the use of same component made from non- compound polypropylene.

[0086] Returning now to Figure 3  in an embodiment  strips 345  348 comprises polypropylene  and each have a thickness of between 10 mil and 40 mil. In an embodiment  strips 345  348 are each approximately 10 mil  15 mil  20 mil or 25 mil thick. In an embodiment  strips 345  348 may be of another suitable thickness. It is not necessary that each of the strips 345  348 are the same thickness. [0087] In an embodiment  at least one strip 345  348 is made from a polypropylene / calcium carbonate compound comprising at least 50%  but not more than 66% calcium carbonate by weight. In an embodiment  at least one strip 345  348 is made from a polypropylene / calcium carbonate compound comprising approximately 60% calcium carbonate by weight. A strip 345  348 made from a polypropylene / calcium carbonate compound comprising at least 50% calcium carbonate by weight  is expected to have higher thermal conductivity than a strip made from polypropylene alone  or than a strip made from a polypropylene / calcium carbonate compound comprising less than 50% calcium carbonate by weight. Because of the higher thermal conductivity using at least one strip 345  348 made from a compound of polypropylene and calcium carbonate comprising at least 50% calcium carbonate by weight  it is anticipated that the adhesive 335 will set faster  and thus  apparatus 100 will operate at higher overall throughput than it would when using strips 345  348 comprising more than 50% polypropylene.

[0088] In an embodiment  adhesive 335 comprises polypropylene  and is applied in a layer having a thickness of between 10 mil and 40 mil. In an embodiment  the layer of adhesive 335 is approximately 10 mil  15 mil  20 mil or 25 mil thick. In an embodiment  the layer of adhesive 335 is another suitable thickness.

[0089] In an embodiment  the adhesive 335 is made from a polypropylene / calcium carbonate compound comprising at least 50%  but not more than 66% calcium carbonate by weight. In an embodiment  the adhesive 335 is made from a polypropylene / calcium carbonate compound comprising approximately 60% calcium carbonate by weight. The adhesive 335 made from a polypropylene / calcium carbonate compound comprising at least 50% calcium carbonate by weight  is expected to have higher thermal conductivity than an adhesive made from polypropylene alone  or than an adhesive made from a polypropylene / calcium carbonate compound comprising less than 50% calcium carbonate by weight. Because of the higher thermal conductivity using an adhesive 335 made from a compound of polypropylene and calcium carbonate comprising at least 50% calcium carbonate by weight  it is anticipated that it will set faster  and thus  apparatus 100 will operate at higher overall throughput than it would when using an adhesive 335 comprising more than 50% polypropylene.

[0090] In an embodiment  the backing of cover 325 comprises polypropylene  and the backing comprising polypropylene is in a layer having a thickness of between 10 mil and 40 mil. In an embodiment  the backing layer of the composite cover material 325 is approximately 10 mil  15 mil  20 mil or 25 mil thick. In an embodiment  the backing of the composite cover material 325 is another suitable thickness.

[0091] In an embodiment  the backing of the composite cover material 325 is formed from a polypropylene / calcium carbonate compound comprising at least 50%  but not more than 66% calcium carbonate by weight. In an embodiment  the backing of the composite cover material 325 is formed from a polypropylene / calcium carbonate compound comprising approximately 60% calcium carbonate by weight. The backing of the composite cover material 325 formed from a polypropylene / calcium carbonate compound comprising at least 50% calcium carbonate by weight  is expected to have higher thermal conductivity than a backing made from polypropylene alone  or than a backing made from a polypropylene / calcium carbonate compound comprising less than 50% calcium carbonate by weight. Because of the higher thermal conductivity using a composite cover material 325 having a backing formed from a compound of polypropylene and calcium carbonate comprising at least 50% calcium carbonate by weight  it is anticipated that the adhesive 335 will set faster  and thus  apparatus 100 will operate at higher overall throughput than it would when using a composite cover material 325 having a backing formed from a compound of polypropylene and calcium carbonate comprising more than 50% polypropylene.

[0092] The following tables presents illustrative paint rollers that will be used in the discussion below.

[0093] The following table presents illustrative paint rollers that can be formed using the invention disclosed herein. The "Cover" column refers to the cover material 325 used  the "Adhesive" column refers to the adhesive 335 used  the "Strip 1" column refers to the strip 345 used and the "Strip 2" column refers to the strip 348 used in the example. As above  for each column  the entry reflects the thickness in mil  and the percentage of calcium carbonate (by weight) compounded with polypropylene to form the component. The thickness in mil for the "Cover" column reflects the thickness of the layer 335 used to form the composite cover material 325 - the "Cover" column entries showing a thickness of 0 reflect the use of a cover material rather than a composite cover material.

[0094] Example Cl and Dl  each make paint rollers of the same thickness  however  the characteristics of the paint roller Dl are substantially improved when compared to those of Cl. The Dl paint roller feels firmer and is of higher quality than the Cl paint roller. Moreover  the 40 mil thick core of the Dl paint roller uses only 42% of the polypropylene used to manufacture the Cl paint roller (excluding any polypropylene in the cover material).

[0095] Example D2 forms a paint roller with very good properties and firmness. This roller compares favorably to Example Dl due to its extra 10 mil thickness. Moreover  Example D2 compare favorably not only to Example Cl  but to Example C2 having a core of the same thickness (50 mil)  and even to Example C3  despite Example C3 having a core of 70 mil and using substantially more than twice as much polypropylene. Example D3 makes an even better paint roller  while Example D4 makes an excellent quality paint roller. Notably  while Example D4 is the same core thickness as example C3  it uses only about 46% as much polypropylene. [0096] As above  many other variations are possible. For example  it is not necessary to use both a compound adhesive and a strip formed from compounding polypropylene and calcium carbonate. Moreover  it is not necessary to form both strips from a compound adhesive. In addition  it is not necessary to use a composite cover material formed from a compound of polypropylene / calcium carbonate. The use of (i) a compound strip  (ii) compound adhesive or (ii) composite cover material formed from a compound of polypropylene / calcium carbonate  will each produce a stronger roller  with less polypropylene  than the use of same component made from non-compound polypropylene. [0097] Further  it has been observed that the two-strip 60 mil core roller of Example C4 provides approximately the same qualities as the single strip  40 mil core roller of Example A2  while the latter roller uses only about 37% as much polypropylene. Also  notably  the two-strip 50 mil core Example D2 provides a much stronger roller than the two-strip 60 mil core roller made according to Example C4.

[0098] Returning to Figure 4  in an embodiment  one or both of the strips 445  448 can be made from a compound of polypropylene and calcium carbonate having at least 50%  but not more than about 66% calcium carbonate by weight. Similarly  in an embodiment the cover 415 may having a backing made of a compound of polypropylene and calcium carbonate having at least 50% but not more than 66% calcium carbonate by weight. As discussed above  the percentage of calcium carbonate used in the compound forming the strips 448  445 and the cover 415 backing may be the same  or may differ from one-another.

[0099] In an embodiment  the strips 445  448 are made from a compound of polypropylene and calcium carbonate having approximately 60% calcium carbonate  and the cover 415 has a backing made of a compound of 105 MFI polypropylene and non-refined calcium carbonate having approximately 25% calcium carbonate by weight.

[0100] Returning to Figure 5 Apparatus 500 may be operated according to the present invention using a preformed core 540 made of a compound of polypropylene and calcium carbonate having at least 50%  but not more than 66% calcium carbonate by weight; and/or using a cover 520 having a backing made of a compound of polypropylene and calcium carbonate having between 5% and 66% calcium carbonate by weight. When more than one component is made of a compound of polypropylene and calcium carbonate  the percentage of calcium carbonate used in the compound forming the core 540 and the cover 520 backing may be the same  or may differ from one-another. In an embodiment  the core 540 is made of a compound of polypropylene and calcium carbonate comprising approximately 60% calcium carbonate by weight  and the cover backing is made of a compound of polypropylene and calcium carbonate comprising approximately 25% calcium carbonate by weight.

[0101] As discussed above Variation in the amount of calcium carbonate are within the scope of the invention  and thus  it will be apparent to one of skill in the art that to some degree thermal conductivity can be controlled  or a desired thermal conductivity or range of thermal conductivity can be achieved by varying the percentage of calcium carbonate in one or more of the compounds. It will be apparent to one of skill in the art that to some degree  stiffness can be controlled  or a desired stiffness or range of stiffness can be achieved by varying the percentage of calcium carbonate in these compounds as well.

[0102] It is possible  without departing from the invention  to use a compound of polypropylene and calcium carbonate having between 50% and 60% calcium carbonate by weight in lieu of polypropylene in making paint rollers. In light of this disclosure  other methods for the manufacture of the same will be apparent to persons of skill in the art.

[0103] Benefits of certain embodiments of the instant invention include: control of thermal conductivity in the component materials leading to faster throughput and/or faster set times; and control of material characteristics such as stiffness for manufacture of harder  more expensive paint rollers.

[0104] The above embodiments and preferences are illustrative of the present invention. It is neither necessary  nor intended for this patent to outline or define every possible combination or embodiment. The inventor has disclosed sufficient information to permit one skilled in the art to practice at least one embodiment of the invention  and has disclosed the ways the inventor now believes are the best ways to practice the invention. The above description and drawings are merely illustrative of the present invention and that changes in components  structure and procedure are possible without departing from the scope of the present invention as defined in the following claims. Thus  while the invention has been particularly shown and described with reference to embodiments thereof  it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. The above embodiments are illustrative of the present invention. It is neither necessary  nor intended for this patent to outline or define every possible combination or embodiment.
What is claimed is:

1. A method of making a paint roller  comprising the steps of:

helically winding a strip of material around a mandrel so as to form a helically wound strip  the strip being formed from a compound of polypropylene and calcium carbonate having at least 5% but not more than 66% calcium carbonate by weight;

advancing the wound strip along the mandrel;

applying a layer of adhesive onto an outer surface of the wound strip; and

helically wrapping a strip of cover material about the wound strip and over the layer of adhesive  thereby bonding the strip of cover material to the wound strip for forming the paint roller.

2. The method of making a paint roller according to claim 1  wherein the strip is formed from a compound of polypropylene and calcium carbonate having at least 50% but not more than 66% calcium carbonate by weight.

3. The method of making a paint roller according to claim 1  wherein the strip is formed from a compound of polypropylene and calcium carbonate having at least 5% but not more than 50% calcium carbonate by weight.

4. A method of making a paint roller  comprising the steps of:

helically winding a strip of material around a mandrel so as to form a helically wound strip;

advancing the wound strip along the mandrel;

compounding an adhesive from polypropylene and calcium carbonate  the compound comprising at least 5% but not more than 66% calcium carbonate by weight;

applying the layer of adhesive onto an outer surface of the wound strip;

helically wrapping a strip of cover material about the wound strip and over the layer of adhesive  thereby bonding the strip of cover material to the wound strip for forming the paint roller.

5. The method of making a paint roller according to claim 4  wherein the compound comprises at least 50% but not more than 66% calcium carbonate by weight.

6. The method of making a paint roller according to claim 4  wherein the compound comprises at least 5% but not more than 50% calcium carbonate by weight.

7. The method of claim 4  wherein the step of compounding is performed by a twin screw extruder.

8. A method for continuously producing a multi-strip laminate paint roller comprising the steps of:

helically advancing an inner strip and an outer strip of material about a mandrel in offset relation  at least one of the strips being formed from a compound of polypropylene and calcium carbonate having between at least 5% but not more than 66% calcium carbonate by weight;

applying a layer of adhesive between the two strips and on the outer surface of the outer strip;

prior to permitting the layer of liquid polypropylene to harden and set  wrapping a cover around the outer strip and applying a compressing force upon the cover urging the cover and the two strips toward the mandrel  thereby creating the continuous laminated paint roller.

9. The method of making a paint roller according to claim 8  wherein the strip is formed from a compound of polypropylene and calcium carbonate having at least 50% but not more than 66% calcium carbonate by weight.

10. The method of making a paint roller according to claim 8  wherein the strip is formed from a compound of polypropylene and calcium carbonate having at least 5% but not more than 50% calcium carbonate by weight.

11. A method for continuously producing a multi-strip laminate paint roller comprising the steps of:

helically advancing an inner strip and an outer strip of material about a mandrel in offset relation;

compounding an adhesive material from polypropylene and calcium carbonate  the compound comprising at least 5% but not more than 66% calcium carbonate by weight;

applying the adhesive material between the two strips and on the outer surface of the outer strip;

prior to permitting the adhesive material to harden and set  wrapping a cover around the outer strip and applying a compressing force upon the cover urging the cover and the two strips toward the mandrel  thereby creating the continuous laminated paint roller.

12. The method of making a paint roller according to claim 11  wherein the compound comprises at least 50% but not more than 66% calcium carbonate by weight.

13. The method of making a paint roller according to claim 11  wherein the compound comprises at least 5% but not more than 50% calcium carbonate by weight.

14. The method of claim 11  wherein the step of compounding is performed by a twin screw extruder.

15. A method for continuously producing a multi-strip laminate paint roller comprising the steps of: helically advancing an inner strip and an outer strip of material about a mandrel in offset relation  at least one of the strips being formed from a compound of polypropylene and calcium carbonate having at least 5% but not more than 66% calcium carbonate by weight;

compounding an adhesive material from polypropylene and calcium carbonate  the compound comprising at least 5% but not more than 66% carbonate by weight;

applying the adhesive material between the two strips and on the outer surface of the outer strip;

prior to permitting the layer of liquid polypropylene to harden and set  wrapping a cover around the outer strip and applying a compressing force upon the cover urging the cover and the two strips toward the mandrel  thereby creating the continuous laminated paint roller.

16. The method of claim 15  wherein the step of compounding is performed by a twin screw extruder.

17. A method of making a laminated paint roller comprising the steps of: helically winding a strip comprising polypropylene around a mandrel so as to form a helically wound strip  the strip having an outer surface; advancing the wound strip along the mandrel; applying a layer of adhesive comprising polypropylene onto the outer surface of the wound strip; and wrapping a strip of composite cover material about the wound strip and over the layer of adhesive  the composite cover material being formed by the steps of: providing a width of porous pile material having a pile side and a fabric underside; advancing the width of pile material with the fabric underside facing up; compounding a backing layer from polypropylene and calcium carbonate  the compound comprising between 5% and 66% calcium carbonate by weight;

applying the backing layer on the fabric underside of the advancing width of pile material so that the layer has one side that is in contact with the fabric underside of the advancing material and an other side that is not in contact with the advancing pile material  the layer being in molten form when it is applied; applying a compressive force to the other side of the layer before the layer hardens and sets  to smooth the other side of the layer of polypropylene  and to urge the layer and the fabric underside of the pile material together  thereby forming a composite material having a smooth or uniformly imprinted non-porous side and a pile side  and wherein the pile is held fast on the composite material; cutting the width of composite material into a strip once the backing layer is no longer in molten form  thereby forming a composite cover material having an inner surface comprising a smooth or uniformly imprinted non-porous polypropylene side and a pile side; and applying a compressive force from without the composite cover material to urge the composite cover material  the layer of adhesive and strip of non-porous polypropylene material together  thereby laminating the smooth inner surface of the composite cover material to the outer surface of the non-porous polypropylene strip.

18. The method of making a laminated paint roller claimed in claim 9  wherein the steps of (i) compounding a backing layer  and (ii) applying a backing layer  are performed by a twin screw extruder that receives polypropylene in pellet form from a polypropylene feeder  and receives calcium carbonate from a calcium carbonate feeder.

19. A method of making a laminated paint roller comprising the steps of: helically winding an inner strip of thermoplastic material around a mandrel so as to form a helically wound inner strip  the inner strip having an outer surface; helically winding a second strip of thermoplastic material around a mandrel in offset relation to the inner strip  so as to form a helically wound second strip  the second strip having an inner surface and an outer surface; advancing the wound inner and second strips along the mandrel;

compounding an adhesive from polypropylene and calcium carbonate  the compound comprising at least 5% but not more than 66% calcium carbonate by weight; applying a layer of the adhesive onto the outer surface of the wound inner strip and the outer surface of the wound second strip; and wrapping a strip of composite cover material about the wound second strip and over the layer of adhesive applied to the wound second strip  the composite cover material having an inner surface and an outer surface  the outer surface of the composite cover material comprising a pile fabric  and the inner surface comprising a smooth generally non-porous backing comprising polypropylene; and applying a compressive force from without the composite cover material to urge the composite cover material  the layer of adhesive and inner and second strips together  thereby laminating the inner surface of the composite cover material to the outer surface of the second strip and laminating the inner surface of the second strip to the outer surface of the inner strip.

20. A method for continuously producing a multi-strip laminate paint roller comprising the steps of:

helically advancing an inner strip and an outer strip of material about a mandrel in offset relation  at least one of the strips being formed from a compound of polypropylene and calcium carbonate at least 5% but not more than 66% calcium carbonate by weight  the inner strip and the outer strip having an outer surface facing away from the mandrel;

heating the outer surface of the inner and outer strips to cause a layer of the outer surface of the strips to become liquefied;

prior to permitting the liquefied layers to harden and set  wrapping a cover around the outer strip and applying a compressing force upon the cover urging the cover and the two strips toward the mandrel  thereby creating the continuous laminated paint roller.

21. The method of making a paint roller according to claim 20  wherein the compound comprises at least 50% but not more than 66% calcium carbonate by weight.

22. The method of making a paint roller according to claim 20  wherein the compound comprises at least 5% but not more than 50% calcium carbonate by weight.