Abstract:
A method of preparing a scented ink composition comprising the steps of first preparing a mixture which includes a polymer component consisting of a water soluble polymer selected form the group consisting of acrylic, styrene-maleic anhydride, sulfonated polyester, polyamide, and polyurethene. A color component which is selected from the group consisting of a pigment and a dye, and a solvent component comprising water are also provided. The mixture is then agitated. An oil-based fragrance is then blended into this mixture to produce a scented mixture and is then agitated. A microemulsion of the oil-based fragrance in water is created, wherein the resin stabilizes the microdroplets of the oil-based fragrance by coating the microdroplets. Preferably, the microdroplets of the oil-based fragrance have a diameter of from about 0.1 to about 1.0 micrometers.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is not related to any other pending application. 
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to coatings and more particularly to inks. Still more particularly, the present invention relates to coatings which contain components which are odor masking, odor reducing, or perfuming. 
     2. Background Information 
     The prior art discloses the use of fragrant or scented inks for use in various packaging and novelty applications. U.S. Pat. No. 5,018,974 to Carnahan, et al., for example, discloses a publication with image areas that release an appropriate fragrance upon being colored or painted by the user. Microcapsules that contain fragrance oil for a particular fragrance associated with the image area are deposited on the image area of the substrate. Inert walls of materials such as gelatin restrain the fragrance within the microcapsules until activated. A color dispenser such as a felt tip marking pen is adapted to include a reactive agent that when applied to the image area in the normal course of coloring will cause release of the fragrance by rupturing or otherwise interacting with the microcapsules such as by diffusing into the microcapsules and replacing and releasing the oil. The reactive agent may be a solvent such as an alcohol or ketone or a surfactant contained in an aqueous solution mixed with the normal ink or paint of the marking pen. The invention enables release of fragrances in the normal course of coloring an image without requiring action such as scratching or pulling apart of the sheets on which the image is placed. 
     U.S. Pat. No. 5,577,947 to Malloy, et al. discloses a scented ink composition and method of printing in which a scented ink image is applied to a novelty item such as a balloon. The scented ink comprises a mixture of a conventional printing ink with a fragrant oil wherein the fragrant oil is added to the printing ink at a concentration from 4-7% by weight. After mixing, the scented ink solution is used in place of conventional printing ink in a flexographic printing press, and the press is operated in a normal fashion to print images on metalized nylon sheeting used in the manufacture of balloons. After printing the scented ink images onto the sheeting, the image is dried in a conventional manner and the matter is wrapped in polyethylene for storage until used in the manufacture of the balloons. 
     U.S. Pat. No. 6,123,757 to Yang, et al. discloses a fragrant ink for use in a microjet printer. This fragrant ink composition comprises an alcohol component in an amount of 1-20% by weight, an imaging component which may be a pigment used in the amount of 1-10% by weight, a fragrant agent component used in the amount of 0.05-20% by weight, and an additional ethanol component used in the amount of 2-20% by weight which reduces drying time of the ink. 
     A problem, however, which has attended the use of scented or fragrant ink in that the scents or fragrances may not last for extended periods of time. Particularly for packaging applications, the failure of ink to retain its scent over an extended period of time, where the package may be in storage or shipping, may seriously detract from the overall desirability of using the scented ink. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a scented ink which retains its scent or fragrance over an extended period of time. 
     This and other objects are met by the present invention which is a method of preparing a scented ink composition comprising the steps of first preparing a mixture which includes a resin component consisting of a water soluble polymer selected from the group consisting of acrylic, styrene-maleic anhydride, sulfonated polyester, polyamide, and polyurethane, a color component selected from the group consisting of a pigment and a dye, and a solvent component comprising water. The mixture is then agitated. An oil-based fragrance is blended into this mixture to produce a scented mixture, and is then agitated. A microemulsion of the oil-based fragrance in water is created, wherein the resin stabilizes the microdroplets of the oil-based fragrance by coating the microdroplets. Preferably, the microdroplets of the oil-based fragrance have a diameter of from about 0.1 to about 1.0 micrometers. 
     Also encompassed by the present invention is a scented ink composition produced by a method comprising the steps of first preparing a mixture which includes a resin component consisting of a water soluble polymer selected from the group consisting of acrylic, styrene-maleic anhydride, sulfonated polyester, polyamide, and polyurethane, a color component selected from the group consisting of a pigment and a dye, and a solvent component comprising water. The mixture is then agitated. An oil-based fragrance is blended into this mixture to produce a scented mixture, and is then agitated. A microemulsion of the oil-based fragrance in water is created, wherein the resin stabilizes the microdroplets of the oil-based fragrance by coating the microdroplets. Preferably, the microdroplets of the oil-based fragrance have a diameter of from about 0.1 to about 1.0 micrometers. It is also believed that in this composition these microdroplets will tend to be coated by the resin component. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The resin component of the ink will preferably be provided by an acrylic varnish in the amount of 15%-45% by weight of the entire composition and an acrylic emulsion in the amount of 0-30% by weight of the entire composition. The acrylic varnish has a solids content of about 20% to about 40% by weight. The solvent for the acrylic varnish is water. A general procedure for preparing this acrylic varnish is as follows. Water is added in a mill (Kady) or high speed mixer. Ammonia (21°Bé) is added and mixed with water. The polymer is added and mixed until completely dissolved. 
     The acrylic emulsion is an emulsion of acrylic monomers and a water solvent. These monomers may be selected from methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl methacrylate, butyl methacrylate, acrylonitrile, acrylic acid, methacrylic acid, itaconic acid, malic acid, fumaric acid, acrylic anhydride, methacrylic anhydride, maleic anhydride, itaconic anhydride, fumaric anhydride, styrene, substitued styrene, vinyl acetate, and other C.sub.1 to C.sub.12 alkyl acrylates and methacrylates. Polymerization of the above monomers takes place in situ by emulsion polymerization. Preferably, the glass transition temperature of the polymer is in the range of about −40° C. to about +50° C. 
     In a preferred composition, the pigment dispersion will be used in the amount of 25%-65% by weight. This pigment dispersion may be either an organic or inorganic pigment dispersion. Preferred organic pigments are phthalocyanines, azos, naphthols, and rhodamines. Preferred inorganic pigments are titanium oxide, iron oxides, and carbon black. Preferred carriers are water, acrylic resin solution, glycol, and surfactant. Preferably, the pigment particles will have a particle size of less than about 3000 nanometers. (3 micrometers). Alternatively, the color component may be a dye. Suitable dyes include acid, basic, direct, and disperse dyes. 
     Deionized water in the amount of 0-15% by weight will next be added to the mixture. A wax compound which will preferably be a polymeric wax selected from polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), or a blend of polyethylene (PE) and polytetrafluoroethylene (PTFE) will then be added to the mixture in the amount of 3%-6% by weight. A defoamer which will preferably be mineral oil, silicone, polysiloxane, or silicone-free will then be added to the mixture in the amount of 0.2%-0.5% by weight after which the mixture will be added to a mixing vessel and blended under high speed mixing preferably for at least about 15 minutes. An oil based fragrance is added last, slowly and under high speed mixing, to affect a emulsification of the fragrance in the water system. Suitable oil based fragrances include chocolate, cherry, lemon, peppermint, coffee and similar fragrances. During the manufacturing process, a microemulsion of the oil-based fragrance in water is created via high speed mixing. The microdroplets of the fragrance are stabilized by the high solids content of the acrylic varnish/acrylic emulsion system, whereby the resin molecules coat the microdroplets of the fragrance to ensure stability and long lasting effect of the scent. The process is preferably carried out at room temperature and at normal atmospheric pressure. The viscosity of the final ink is preferably in the range of 20-35 seconds as measured in a #4DIN Cup. The pH will preferably be between 8.0-9.5. Both viscosity and pH are typical for water based flexographic inks. 
     The method of the present invention is further described with reference to the following examples. 
    
    
     EXAMPLE A 
     A varnish was made by adding liquid components 1-4 and 6 into a Kady mill in their order shown in Table I. The resin component 5 was then added and mixing was done until all resin was dissolved. 
     
       
         
               
               
               
             
               
               
               
             
           
               
                 TABLE I 
               
               
                   
               
               
                 COMPONENT 
                 DESCRIPTION 
                 % BY WEIGHT 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1. 
                 Water 
                 51.4% 
               
               
                 2. 
                 MEA (HVC) 
                 4.0% 
               
               
                 3. 
                 Aqua Ammonia 21° 
                 6.6% 
               
               
                   
                 Bammé (HVC) 
               
               
                 4. 
                 Defoamer - Foamaster 
                 0.5% 
               
               
                   
                 WB (Zimmerman) 
               
               
                 5. 
                 Joncryl 678 Resin 
                 34.0% 
               
               
                   
                 (Johnson) 
               
               
                 6. 
                 Dowanol PM Solvent 
                 3.5% 
               
               
                   
                 (HVC) 
               
               
                   
               
             
          
         
       
     
     EXAMPLE B 
     Another varnish was made by adding liquid components 1-4 and 6 from Table II into a Kady mill in their order shown in Table II. The resin component 5 from Table II is then added and mixing is done until all resin is dissolved. 
     
       
         
               
               
               
             
               
               
               
             
           
               
                 TABLE II 
               
               
                   
               
               
                 COMPONENT 
                 DESCRIPTION 
                 % BY WEIGHT 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1. 
                 Water 
                 53.0% 
               
               
                 2. 
                 MEA (HVC) 
                 6.0% 
               
               
                 3. 
                 Aqua Ammonia 21° 
                 3.2% 
               
               
                   
                 Bammé (HVC) 
               
               
                 4. 
                 Defoamer - Foamaster 
                 0.3% 
               
               
                   
                 WB (Zimmerman) 
               
               
                 5. 
                 Joncoyl 678 Resin 
                 34.0% 
               
               
                 6. 
                 Dowanol PM Solvent 
                 3.5% 
               
               
                   
                 (HVC) 
               
               
                   
               
             
          
         
       
     
     EXAMPLE 1 
     Components 1-2, the varnish and polymer emulsion shown in Table III, were added to a high speed mixer. Components 3-6 in Table III, the pigment dispersion, water, and defoamer, respectively, were then also added to the mixer. These components were then mixed at a speed of 1000 RPM for a period of 15 minutes. Component 7 from Table III, the oil-based fragrance, was then added while mixing continued. After addition of the fragrance, mixing continued at a speed of 1000 RPM for a period of 15 minutes. 
     
       
         
               
               
               
             
               
               
               
             
           
               
                 TABLE III 
               
               
                   
               
               
                 COMPONENT 
                 DESCRIPTION 
                 % BY WEIGHT 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1. 
                 Varnish from Example 
                 30.30% 
               
               
                   
                 “A” 
               
               
                 2. 
                 Joncryl SCX-2630 
                 6.00% 
               
               
                   
                 (Johnson) 
               
               
                 3. 
                 Black-BK7R162 Carbon 
                 50.00% 
               
               
                   
                 (Reitech) 
               
               
                 4. 
                 Water 
                 4.00% 
               
               
                 5. 
                 Wax Compound 8855B 
                 4.50% 
               
               
                   
                 (08-15223) 
               
               
                 6. 
                 Defoamer Foammaster 
                 0.20% 
               
               
                   
                 WB (Zimmerman) 
               
               
                 7. 
                 (S) chocolate (FG8640) 
                 5.00% 
               
               
                   
                 Intercontinental 
               
               
                   
               
             
          
         
       
     
     EXAMPLE 2 
     In this example the components shown in Table IV, component 1, which was a varnish, and component 2, which was the acrylic emulsion, were added to the mixer used in Example 1 along with components 3-5 which were pigment dispersions and components 6-8, respectively the water, wax compound, and defoamer. These components were blended in the mixer at a speed of 1000 RPM for a period of 15 minutes. While mixing continued, the fragrant component was added, after which mixing continued at a speed of 1000 RPM for an additional 15 minutes. 
     
       
         
               
               
               
             
               
               
               
             
           
               
                 TABLE IV 
               
               
                   
               
               
                 COMPONENT 
                 DESCRIPTION 
                 % BY WEIGHT 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1. 
                 Varnish from Example 
                 21.00% 
               
               
                   
                 “B” 
               
               
                 2. 
                 A-6037 (Zeneca) (Neo- 
                 10.00% 
               
               
                   
                 Resins) 
               
               
                 3. 
                 Blue-BFD4291 
                 28.00% 
               
               
                   
                 Flexiverse (Sun) 
               
               
                 4. 
                 Yellow-YCD 9274 
                 14.00% 
               
               
                   
                 Blend (Sun) 
               
               
                 5. 
                 Black-BK7R162 
                 6.00% 
               
               
                   
                 Carbon (Reitech) 
               
               
                 6. 
                 Water 
                 5.00% 
               
               
                 7. 
                 Wax Compound 8855B 
                 5.00% 
               
               
                   
                 (08-15223) 
               
               
                 8. 
                 Defoamer Foammaster 
                 0.20% 
               
               
                   
                 WB (Zimmerman) 
               
               
                 9. 
                 (S) Coffee (FG6006) 
                 10.80% 
               
               
                   
                 Intercontinental 
               
               
                   
               
             
          
         
       
     
     EXAMPLE 3 
     In this example the components shown in Table V were used. Component 1, which was acrylic varnish, and component 2, which was acrylic emulsion, were added to the mixer used in the previous Example 1 along with components 3-5 which were pigment dispersions. Components 6, 7, and 8, respectively water, wax compound, and defoamer, were then added to the mixture, after which the mixture was blended at a speed of 1000 RPM for a period of 15 minutes. While blending continued, component 9, the fragrance, was added after which mixing continued for an additional 15 minutes. The viscosity of the completed ink was 20-30 #DIN, and the pH was 8.8-9.3. 
     
       
         
               
               
               
             
               
               
               
             
           
               
                 TABLE V 
               
               
                   
               
               
                 COMPONENT 
                 DESCRIPTION 
                 % BY WEIGHT 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1. 
                 Varnish from Example 
                 20.00% 
               
               
                   
                 “B” 
               
               
                 2. 
                 A-6037 (Zeneca) (Neo- 
                 7.00% 
               
               
                   
                 Resins) 
               
               
                 3. 
                 Blue-BFD4291 
                 5.00% 
               
               
                   
                 Flexiverse (Sun) 
               
               
                 4. 
                 Yellow-YCD 9274 
                 20.00% 
               
               
                   
                 Blend (Sun) 
               
               
                 5. 
                 Green-DC-G-07001 
                 28.00% 
               
               
                   
                 Decosperse 7 (Quaker) 
               
               
                 6. 
                 Water 
                 10.00% 
               
               
                 7. 
                 Wax Compound 8855B 
                 4.50% 
               
               
                   
                 (08-15223) 
               
               
                 8. 
                 Defoamer Foammaster 
                 0.20% 
               
               
                   
                 WB (Zimmerman) 
               
               
                 9. 
                 (S) Peppermint 
                 5.30% 
               
               
                   
                 (FG0348) Intercon 
               
               
                   
               
             
          
         
       
     
     EXAMPLE 4 
     In this example the components shown in Table VI are used. Component 1, which is a commercially available styrenated-maleic anhydride resin, and component 2 which is an acrylic emulsion, are added to the mixer used in Example 1 along with component 3 which is a pigment dispersion and components 4-6, respectively the water, wax compound and defoamer. These components are blended in the mixer at a speed of 1000 RPM for a period of 15 minutes. While mixing continues, the fragrant component 7 is added after which mixing continues at a speed of 1000 RPM for an additional 15 minutes. 
     
       
         
               
               
               
             
               
               
               
             
           
               
                 TABLE VI 
               
               
                   
               
               
                 COMPONENTS 
                 DESCRIPTION 
                 % BY WEIGHT 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1. 
                 SMA 17352H (Elf A-to- 
                 15.0% 
               
               
                   
                 chem) 
               
               
                 2. 
                 Joncryl ECO-2177 
                 40.0% 
               
               
                   
                 (Johnson) 
               
               
                 3. 
                 Yellow - YGD9374 
                 32.0% 
               
               
                   
                 (Sun) 
               
               
                 4. 
                 Water 
                 2.3% 
               
               
                 5. 
                 Wax Compound 8855B 
                 4.5% 
               
               
                   
                 (08-15223) 
               
               
                 6. 
                 Defoamer - Foamaster 
                 0.2% 
               
               
                   
                 WB (Zimmerman) 
               
               
                 7. 
                 (S) Lemon (FG0160) 
                 6.0% 
               
               
                   
                 Intercontinental 
               
               
                   
               
             
          
         
       
     
     EXAMPLE 5 
     In this example the components shown in Table VII are used. Components 1 and 2 which are commercially available sulfonated polyester resins are added to the mixer used in Example 1 along with component 3 which is a pigment dispersion and components 4-6 which are respectively the water, wax compound and defoamer. These compounds are blended, in the mixer at a speed of 1000 RPM for a period of 15 minutes. While mixing continues, the fragrant component 7 is added after which mixing continues at a speed of 1000 RPM for an additional 15 minutes. 
     
       
         
               
               
               
             
               
               
               
             
           
               
                 TABLE VII 
               
               
                   
               
               
                 COMPONENT 
                 DESCRIPTION 
                 % BY WEIGHT 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1. 
                 Eastek 2140 (Eastman) 
                 42.8% 
               
               
                 2. 
                 Eastek 1300 (Eastman) 
                 14.0% 
               
               
                 3. 
                 Blue levanyl G-LF-01 
                 30.0% 
               
               
                   
                 (Bayer) 
               
               
                 4. 
                 Water 
                 2.5% 
               
               
                 5. 
                 Surfynol 104PA 
                 0.5% 
               
               
                   
                 Surfactant (Air 
               
               
                   
                 Products) 
               
               
                 6. 
                 Wax Compound 8855B 
                 4.5% 
               
               
                   
                 (08-15223) 
               
               
                 7. 
                 Defoamer Foamaster 
                 0.2% 
               
               
                   
                 WB (Zimmerman) 
               
               
                 8. 
                 (S) Cherry (FG9454) 
                 5.5% 
               
               
                   
                 Intercontinental 
               
               
                   
               
             
          
         
       
     
     Table VIII shows pH, viscosity and fragrance durability for the inks made in Examples 1-3. 
     As is shown in Table VIII, inks made according to these examples, surprisingly and unexpectly, maintain their fragrance for substantially longer periods of time than do many conventional scented inks. 
     
       
         
               
               
               
               
               
             
           
               
                   
                 TABLE VIII 
               
               
                   
                   
               
               
                   
                   
                   
                   
                 FRAGRANCE 
               
               
                   
                   
                   
                   
                 DURABILITY (IN 
               
               
                   
                   
                   
                 VISCOSITY 
                 OPEN AIR 
               
               
                   
                   
                   
                 (SEC) #4 DIN 
                 AFTER 
               
               
                   
                 INK 
                 pH 
                 CUP 
                 PRINTING 
               
               
                   
                   
               
             
             
               
                   
                 Example 1 
                 8.3-9.0 
                 20-25 
                 Approximately 2 
               
               
                   
                   
                   
                   
                 weeks 
               
               
                   
                 Example 2 
                 8.3-9.0 
                 20-25 
                 Approximately 2 
               
               
                   
                   
                   
                   
                 weeks 
               
               
                   
                 Example 3 
                 8.8-9.3 
                 20-30 
                 Approximately 2 
               
               
                   
                   
                   
                   
                 weeks 
               
               
                   
                   
               
             
          
         
       
     
     While not intending to be bound by any theory of why the method described herein produces inks with the extended fragrance durability, it is believed that this advantageous result occurs at least in part due to the sequence of first mixing and agitating all the components except the fragrance and then adding the fragrance and again agitating. It is also believed that a microemulsion of the oil based fragrance in water is formed with microdroplets having diameters of from about 0.1 micrometer to about 1.0 micrometer and that the resin component coats these microdroplets. Such coating of the microdroplets by the resin component is also believed to contribute to extended fragrance durability. 
     The inks are applied to the substrate by conventional means utilizing water flexographic printing presses. 
     It will be appreciated that a scented ink and a method of its preparation which results in an ink which maintains its fragrance for an extended period of time. This ink may be prepared cost effectively, and may be used on a range of conventional packaging substrates. 
     While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.