Patent Document

RELATED APPLICATION  
       [0001]     This application claims priority of U.S. Provisional Patent Application Ser. No. 60/511,810 filed Oct. 16, 2003, which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention generally relates to gelled composition applicators and in particular to gelled anaerobic curing composition applicators containing inorganic thickeners that are well suited in the thread locking setting.  
       BACKGROUND OF THE INVENTION  
       [0003]     Historically, thread lockers have been liquids of varying viscosity. These liquids have met with limited acceptability owing to handling properties. Liquid thread lockers tend to be difficult to apply in overhead settings and are generally considered to be imprecise owing to drippage from the cap running down the exterior of the primary package and seepage of the material to places where locking is deemed undesirable. As a result of these handling properties, a conventional liquid thread locker typically requires a secondary package to prevent leakage onto surrounding tools or apparel.  
         [0004]     Various attempts have been made in the prior art to add various waxes, polymers, and organic species to a liquid thread locker composition in order to address these limitations. Representative of these attempts are U.S. Pat. Nos. 3,547,851; 4,497,916 and 6,451,927. In particular, U.S. Pat. No. 6,451,927 B1 utilizes an organically thickened anaerobic composition provided in a lipstick-type applicator. While this thickened composition is effective in allowing overhead thread locker application and the prevention of drippage, the method of application of wiping a bolt across a raised applicator face tends to smear thread locker composition onto the outer surfaces of the applicator so as to require applicator wiping prior to cap replacement. Additionally, under compressive forces, liquid and conventionally thickened thread locker compositions tend to be forced from the site where adhesive bonding is actually required. Thus, there exists a need for a gelled anaerobic composition that is provided in a readily resealable applicator where the gelled anaerobic composition is delivered with greater precision.  
       SUMMARY OF THE INVENTION  
       [0005]     An adhesive composition applicator includes a housing having sidewalls and a neck that tapers to an opening. The housing encloses a gelled adhesive composition. The housing has a cross-sectional area and the opening has a cross-sectional area less than that of the housing cross-sectional area. A cap is provided that engages the housing. A mechanism is provided for urging the gelled composition material from the housing through the opening. The neck optionally also includes a shield to prevent gelled adhesive composition from running down the neck and provides a barrier against gelled adhesive smear reaching the point of intersection between the cap and the housing.  
         [0006]     To facilitate application of gelled composition to a point of application, a spatula is provided adjacent to the opening. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a perspective view of an applicator according to the present invention; and  
         [0008]      FIG. 2  is a perspective view of another embodiment of an inventive applicator according to the present invention adapted to mount on a user hand. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0009]     While the present invention is detailed herein with respect to gelled anaerobic compositions packaged in a stick form, it is appreciated that an applicator according to the present invention is likewise operative with compositions illustratively including epoxies, acrylics, olefinics, and combinations thereof. Further, it is recognized that a liquid curable component or one dissolved in a suitable solvent is amenable to thickening and packaging according to the present invention. A thickener is mixed therewith in a sufficient quantity to create a gelled composition suitable for packaging in an applicator.  
         [0010]     Referring now to  FIG. 1 , an adhesive composition applicator is shown generally at  10 . The applicator  10  includes a housing  12  that is characterized by a housing cross-sectional area  14 . The housing cross-sectional area  14  being bounded by a sidewall  16 . The housing  12  terminates in an opening  18  that is characterized by an opening cross-sectional area  20 . A neck  22  is intermediate between the opening  18  and the sidewall  16 . The opening cross-sectional area  20  according to the present invention is less than 90% of the housing cross-sectional area. Preferably, the opening cross-sectional area is less than 70% of the housing cross-sectional area. More preferably, the opening cross-sectional area is between 2 and 40% of the housing cross-sectional area. Most preferably, the opening cross-sectional area is between 2 and 10% of the housing cross-sectional area. It is appreciated that the length of the neck  22  and therefore the degree of taper therein is a matter of design choice based on variables including adhesive composition viscosity, extrusion force, and applicator construction material properties.  
         [0011]     While the thickness and materials from which a sidewall  16  and other housing components are produced is in part dictated by the forces exerted by the extrusion mechanism, an inventive housing is illustratively formed from materials such as plastics, metal, glass, ceramic and combinations thereof. Preferably, a housing  12  according to the present invention is formed of an injection moldable thermoplastic material.  
         [0012]     While the housing of  FIG. 1  is depicted having a circular housing cross section and a circular opening cross section, it is appreciated that any number of cross-sectional shapes are operative for the housing and opening within an applicator according to the present invention. These various cross-sectional shapes for an inventive applicator illustratively include oval, elliptical, rectilinear, polygonal and more complex forms.  
         [0013]     A mechanism (not shown) is provided for urging a gelled adhesive composition  26  from the housing  12  and through the opening  18 . The gelled adhesive composition  26  exits the opening  18  as a column having the cross-sectional shape and dimension corresponding to the opening cross-sectional area  20 . The gelled adhesive composition  26  in usage is brought into contact with a substrate to be adhesively secured such as a threaded fastener (not shown). Through contact with a substrate, gelled adhesive composition  26  is deformed and invariably creates composition residue as depicted at  28  on the neck portion  22 . The mechanism by which gelled adhesive composition  26  is urged from the housing  12  is that conventional to the art and illustratively includes a screw mechanism that converts rotation of a base into lateral movement of a plunger within the housing  12 ; additionally, a plunger is also an illustrative mechanism operative in the context of the present invention.  
         [0014]     A cap  30  is adapted to selectively engage the housing  12  in the vicinity of the base  32  of the neck  22 . The cap  30  selectively secures to the housing  12  through a variety of conventional mechanisms illustratively including complementary threads, friction fit, a Luer-type coupling. Preferably, the cap  30  friction fits to the housing  12 . More preferably, the cap  30  has a catch  32  complementary to a corresponding neck ridge  34  proximal to the neck base  33 . The cap  30  is typically formed of materials used to form the housing  12 . Preferably, the cap  30  is formed of an injection moldable thermoplastic material.  
         [0015]     Optionally, intermediate between the neck base  32  and the opening  18 , the neck  22  includes a shield  36 . The shield  36 , if present, is sized such that the cap  30  engages the neck base  33 .  
         [0016]     In operation, an inventive applicator  12  by having an opening  18  with a smaller cross-sectional area  20  than that of the housing  14  in which a gelled adhesive is stored allows for gelled adhesive residue  28  that collects on the neck  22  to avoid displacement when the cap  30  is placed thereover. Additionally, gelled adhesive residue  28  is readily applied to an adhesive substrate directly from the neck  22  thereby making more efficient use of the gelled adhesive composition content. In contrast to the prior art, placement of a cap does not displace gelled adhesive residue to a location external to the housing  12  where the adhesive can contaminate user skin or other proximal surfaces. In instances where the neck includes an additional shield  36 , an added barrier is provided against gelled adhesive debris reaching the point of intersection between a cap  30  and an adhesive housing  12 .  
         [0017]     Referring now to  FIG. 2 , an alternate embodiment of an inventive adhesive composition applicator is shown generally at  50  where like numbers have the meaning provided with respect to  FIG. 1 . The applicator  50  has a spatula  52  onto which adhesive composition  26  is extruded. Spatula  52  serves as an application surface to be brought into contact with a substrate to be adhesively secured such as a threaded fastener. The applicator  50  is shown with an elliptical opening cross-sectional area  58  and a crescent-shaped housing cross-sectional area  55 . The applicator  50  optionally includes a strap  54  adapted to secure to the back of a user hand (shown in ghost). Through the use of the strap  54 , a gelled adhesive composition  26  is urged from the housing  12  through lateral compressive forces on the housing  12 . The embodiment depicted in  FIG. 2  at  50  affords application of gelled adhesive composition while a user&#39;s hands are otherwise occupied. In this embodiment, the housing cross-sectional shape changes along the length thereof and becomes circular proximal to the neck  33 . Threads  56  are integral with the exterior of sidewall  16  proximal to the neck  33 . The threads  56  are complementary to threads on a complementary cap (not shown).  
         [0018]     In operation, a curable gelled adhesive composition according to the present invention is formed from a variety of polymerizable monomers alone or in solvated form. The identity of the solvent is largely dictated by the solubility characteristics of the polymerizable monomer and compatibility of that solvent with the other chemical reactants. Solvents operative herein illustratively include: water, C 2 -C 20  linear or branched alkanes; ethers; esters; alcohols; ketones; aldehydes; acids; C 6 -C 10  aromatics and substituted aromatics; furans; and chlorinated, brominated, and fluorinated forms thereof; plasticizers; oils, such as dioctyl phthalate (DOP); and liquid resins such as triethylene glycol dimethacrylate (triEGMA) and polyethylene glycol dimethacrylate (PEGMA).  
         [0019]     The identity of the polymerizable monomer operative in the present invention includes those detailed in U.S. patent application Publication 2002/0111439, which is incorporated herein by reference.  
         [0020]     In addition to the polymerizable monomer, alone or in solvated form, a gelled composition preferably includes an inorganic thickener. Inorganic thickeners operative herein illustratively include silica in fumed or colloidal states; graphite particulate, turbostratic carbon, carbon fiber, carbon nanotubes, fullerenes; clay, diatomaceous earth; boric acid; and combinations thereof. An inorganic thickener is typically present from 5 to 50 total weight percent of the gelled adhesive composition. It is appreciated that the specific amount of inorganic thickener needed is dependent upon variables illustratively including polymerizable monomer viscosity, alone or in solvated state; thickener surface area; thickener hydrophobicity; and resulting adhesive joint strength. Preferably, the inorganic thickener is fumed silica present from 2 to 20 total weight percent of the gelled adhesive composition. A commercially available form of fumed silica operative herein is CAB-O-SIL M5 (Cabot Corp., Tuscola, Ill.).  
         [0021]     In addition to an inorganic thickener, an inventive gelled adhesive composition optionally includes a rheological additive to further modify the viscosity of the gelled adhesive composition. Rheological additives compatible with polymerizable monomers and the inorganic thickeners detailed herein are well known to the art. Rheological additives operative herein illustratively include diols, triols, diacids, triacids, diamides and triamides, polyhydroxy carboxylic acid amides, and combinations thereof. Preferably, the rheological additive is a polyhydroxy carboxylic acid amide. A polyhydroxy carboxylic acid amide operative herein is commercially available under the registered trademark BYK-R 605 (BYK-Chemie, Bad Homburg, Germany).  
         [0022]     In addition to the above-stated components, it is appreciated that an inventive gelled adhesive composition typically includes one or more components illustratively including copolymers, mixtures of polymerizable monomers, polymerization initiators, stabilizers, accelerators, colorants, plasticizers, pigments, fillers, fluorescent agents, and other substances conventional to the art and in conventional quantities. Representative examples of such substances are again found in U.S. patent application Publication 2002/0111439, which is incorporated herein by reference.  
         [0023]     It will be apparent to one skilled in the art to which the invention pertains that various modifications are readily made upon reading the instant specification where these modifications do not depart from the spirit of the invention. These modifications and all equivalents thereof are intended to be encompassed within the appended claims.

Technology Category: b