Abstract:
A grinding composition for sharpening shredder blades of a shredder includes, based on total weight of the grinding composition, from 51 to 65 wt % of a grinding powder; from 5 to 35 wt % of a viscous grease agent; and from 3 to 30 wt % of at least one functional additive. A grinding sheet formed from the composition is used as a grinding product alone or in a bag. The composition is sealed in a bag and used as a grinding product. A process for manufacturing the latter grinding product employs an automatic form-fill-seal packaging machine. The shredder blades of a paper shredder are sharpened satisfactorily by the grinding composition as the grinding sheet or grinding product is shredded. The useful life of shredders is cost effectively extended while providing convenience in use that saves time and labor.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This non-provisional Application claims the benefit of the priority of Applicant&#39;s earlier filed Chinese Patent Application No. 200910056439.5 filed Aug. 14, 2009, the entire contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to the field of shredders, especially to the field of shredder maintenance, and in particular to a grinding composition for sharpening shredder blades, manufactured into a grinding sheet or packaged in a bag as a grinding product, and to a related manufacturing process. 
         [0004]    2. Background of the Related Art 
         [0005]    The main component of existing shredders is a shredder core which has two shredder blade groups inside. When paper is shredded these two shredder blade groups rotate relative to each other to shred paper that enters into a position between them through the cooperation of the shredder blades of the two shredder blade groups. However, as use time increases, shredder blades become progressively duller, which greatly reduces the effectiveness of the shredder and easily leads to mechanical failure such as paper jams, and finally to blade damage and even breakdown of the machine, thereby effecting the normal work. 
         [0006]    The conventional method to address the above-mentioned problem is to disassemble the shredder, dismount the blades of the shredder blade groups, grind the blades to make them sharp again, and reassemble them, so that this method is time-consuming and laborious. Another method is to replace the shredder blade groups directly which, although faster than the first method, has an increased maintenance cost and the shredder must also be disassembled, so that it is still relatively troublesome. 
         [0007]    Objects of the present invention generally pertain to providing: a grinding composition for sharpening shredder blades, a grinding sheet and grinding products, and a related manufacturing process. The grinding composition for sharpening shredder blades should be easy and convenient to prepare, and its raw materials easy to obtain. The grinding sheet and grinding products to be manufactured from the grinding composition have simple structures and are useful to grind shredder blades to sharpen them satisfactorily, while being convenient to use. The grinding sheet and grinding products should be time-saving and labor-saving, extend the useful life of shredders, reduce the cost of use, and therefore be suitable for popularization and application on a large-scale. 
       SUMMARY OF THE INVENTION 
       [0008]    In order to realize the above aims, in a first aspect of the invention, a grinding composition for sharpening shredder blades is provided. In an aspect, the grinding composition for sharpening shredder blades, comprises, based on total weight of the grinding composition, from 51 to 65 wt % of a grinding powder, from 5 to 35 wt % of a viscous grease agent, and from 3 to 30 wt % of at least one functional additive. 
         [0009]    Further in this aspect, the viscous grease agent includes at least one of white oil, animal oil, vegetable oil and stearin candle, and the at least one functional additive includes at least one of an anti-rust powder, an anti-wear powder, an anti-static powder and an anti-oxidation powder. 
         [0010]    Additionally in this aspect, the grinding composition comprises one of: (a) 55 wt % of the grinding powder, 5 wt % of the anti-rust powder, 2 wt % of the anti-wear powder, 35 wt % of the white oil and the vegetable oil combined, 2 wt % of the anti-static powder, and 1 wt % of the anti-oxidation powder, or (b) 57 wt % of the grinding powder, 5 wt % of the anti-rust powder, 35 wt % of the stearin candle, 2 wt % of the anti-static powder, and 1 wt % of the anti-oxidation powder. 
         [0011]    Additionally in this aspect, the stearin candle is prepared by combining stearic acid made from animal or plant fats with white wax, microcrystalline wax and polyethylene wax (PE wax). The grinding powder is a natural mineral grinding powder, the anti-rust powder is aluminum distearate, the anti-wear powder is microcrystalline wax or complex sodium-calcium soap grease, the anti-static powder is glycerol monostearate and the anti-oxidation powder is butylated hydroxytoluene. 
         [0012]    Additionally in this aspect, the natural mineral grinding powder is a natural diamond grinding powder or a natural micron quartz grinding powder. The mesh number of the quartz grinding powder is preferably 260 mesh, and its hardness is 7, so that it is suitable for grinding metal or the like. 
         [0013]    The grinding powder functions to grind the shredder blades to maintain the sharpness of the shredder blades, as well as removing rusty spots, paper scraps, blemishes, etc. from the surface of shredder blades. 
         [0014]    The viscous grease agent may be white wax oil used in cosmetics, baby oil or animal oil or vegetable oil or stearin candle, that is suitable for body contact with people and is naturally biologically degradable. It functions (1) to make the complex sodium-calcium soap grease and (2) as a sticky powder to prevent the grinding powder, the anti-rust powder, the anti-static powder and the anti-oxidation powder from spraying and flying. 
         [0015]    The anti-static powder functions to prevent the shredder blades from rusting, and can coat anti-rust protective films on shredder blades to prevent them from future rusting. Its role is to form a firm adsorption film on the surface of metal, to prevent oxygen and water, particularly water, from contacting the surface of the metal, and to prevent the metal from rusting. Normally, the adsorption forces of the mineral oil, the vegetable oil and the metal are not strong (e.g., the energy of the surface free radicals of the metal is on the order of tenths of one N/m). The surface tension of water is 8×10 −4  N/cm and the surface tension of hydrocarbon is 2×10 −4  N/cm˜3×10 −4  N/cm, so that the oil film formed on the metal is not firm. It is easy to absorb and dissolve part of the water and oxygen, and easy to permeate the oil film. Therefore the anti-rust membrane role played is very weak. If anti-rust powder is added, these shortcomings can be compensated for. 
         [0016]    The anti-static powder functions to eliminate static, to prevent paper scraps and sundries from adhering to shredder blades, and even to prevent the dust explosion of the paper in the shredder closed chamber due to the electric sparks produced by the motor or the static. The anti-static powder prevents paper scraps and powders from adhering to shredder blades, which can lower the paper shredding function of the shredder blades. The anti-static powder is a chemical additive that can prevent the generation of the electrostatic charge or dissipate electrostatic charge effectively. The manner of using anti-static powder is by spreading it on the surfaces of the products or by adding it inside the products. Thus, the anti-static powder can eliminate the electrostatic induction generated by the operation of the shredder blades to eliminate the phenomenon of electric sparks. 
         [0017]    The anti-oxidation powder functions to prevent the metal of shredder blades from oxidizing and rusting. Combined with an anti-rust agent, it has a dual effect and can prevent the oxidative rancidity of the viscous grease agent, the stearin candle. The principle role of an anti-oxidation powder is to prevent or delay metal oxidation but, the anti-oxidation powder must be added before the oxidative deterioration, since it cannot recover after the occurrence of an oxidation reaction. 
         [0018]    The anti-wear powder functions to prevent the surface of the metal of shredder blades from wearing and becoming scratched, and to reduce vibration noise. 
         [0019]    The wear-resistant forming agent (e.g., microcrystalline wax or complex sodium-calcium soap grease) functions to adhere on metal surfaces with good adhesion properties. Combined with micron quartz powder, it can form firm protective films on blades to extend the blade life. The micron quartz powder generally exceeds 120 mesh. 
         [0020]    In a second aspect of the invention, a grinding sheet for sharpening shredder blades is provided. The grinding sheet comprises a sheet made of the grinding composition, which has been stirred, melted and mixed, and cooled and pressed into sheet form, wherein the viscous grease agent includes stearin candle so that the sheet is a solid wax sheet. A grinding product for sharpening shredder blades may comprise the grinding sheet. 
         [0021]    In a third aspect of the present invention, a grinding product for sharpening shredder blades is provided. The product comprises a sealed bag and the above-mentioned grinding composition for sharpening shredder blades positioned inside the sealed bag. 
         [0000]    In this aspect, the sealed bag is made of plastic.
 
Further in this aspect, the sealed plastic bag is made of polypropylene.
 
         [0022]    In a fourth aspect of the invention, a process for manufacturing the above-mentioned grinding product for sharpening shredder blades is provided. The method includes moving and placing a roll of laminated plastic film on an automatic form-fill-seal packaging machine, and sending a measured amount of the grinding composition into a feed chute of the automatic form-fill-seal packaging machine, each measured amount is determined by a fill amount of the grinding composition needed in view of dimensions of the plastic sealed bag including length and width thereof. The measured amount of the grinding composition is filled through the automatic form-fill-seal packaging machine to provide a filled plastic bag. The filled plastic bag is sealed to provide the grinding product. 
         [0023]    In this aspect, the plastic film is a polypropylene plastic film. The main component of the OPP/CPP plastic film material (e.g. OPP/CPP plastic bags) is polypropylene plastic. It can be renewed and reused repeatedly, and be burnt completely without affecting the useful life of an incinerator, and without producing toxic gases, so that secondary environmental pollution is avoided. Therefore, it complies with the requirements of modern environmental protection. 
         [0024]    This aspect may further includes pre-printing on the plastic film at least one of (a) overprinted text that is monochromatic or multicolor overprinted text and (b) pictures. 
         [0025]    The beneficial effects of the invention includes the following:
   (1) The grinding composition for sharpening shredder blades of the invention, comprising the grinding powder, the anti-rust powder, the anti-wear powder, the anti-static powder, the anti-oxidation powder and the viscous agent or stearin candle, is simple and convenient to prepare, the raw materials being easy to obtain. The grinding composition can grind shredder blades and has enhanced functions including anti-rust, anti-static, anti-oxidation, etc., extends the service life of paper shredders, reduces the operating cost, and is suitable for popularization and application on a large-scale.   (2) The invention places the grinding composition for sharpening shredder blades inside a sealed bag. If the grinding composition for sharpening shredder blades can be made to be a solid wax sheet, i.e., a grinding sheet, the bag can be unsealed. Thus, when grinding of shredder blades is needed to regain sharpness, it is not necessary to disassemble the shredder. Rather, the grinding sheet or grinding product, is just inserted directly into the paper inlet as in the process of shredding paper. When the shredder blades cut the grinding product for sharpening shredder blades, for example, the sealed bag is cut open, the grinding powder of the grinding composition inside grinds the shredder blades to make them sharp. Therefore, the grinding sheet and grinding product have simple structures and can grind shredder blades satisfactorily, while being convenient to use, time-saving and labor-saving. They extend the life of the shredders, reduce the operational cost, and are suitable for popularization and application on a large-scale.   (3) The grinding composition for sharpening shredder blades of the invention further comprises trace amounts of functional additives, such as the anti-rust agent, the anti-static powder, the anti-oxidant powder and so on, that can enhance the functions of anti-rust, anti-static, anti-oxidation, etc., so as to further extend the service life of paper shredders and reduce the cost of use.   (4) The grinding sheet and packaged grinding product for sharpening shredder blades of the invention will not pollute a pile of paper scraps and a paper ash-bin, are related shredder products which save energy and are environment-friendly, and can grind shredder blades reliably so as to extend the service life of shredders.   
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]      FIG. 1  is a schematic view of the three-dimensional structure of one embodiment of the grinding product for sharpening shredder blades of the present invention; and 
           [0031]      FIG. 2  is a schematic exploded view of the embodiment shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]      FIGS. 1 and 2  show grinding product  10  including grinding composition  2 , as grinding sheet  2 , positioned in bag  1  between sheets  4  and  5 . Bag  1  is a transparent plastic bag as shown and may be sealed or unsealed. Grinding composition  2  may include functional additives  3 . 
         [0033]    Part I. The steps of the manufacturing process of the grinding product of the powders for sharpening shredder blades of the invention are approximately as follows: 
         [0034]    Working environment: room temperature is 20˜30° C., and relative humidity is about 60˜70%. 
         [0035]    1. Preparing the complex sodium-calcium soap grease with 20% animal oil or vegetable oil and alkali (such as sodium hydroxide, calcium hydroxide, calcium acetate, etc.). 
         [0036]    A saponification reaction is an exothermic reaction, and is a relatively slow chemical reaction. In order to optimize and accelerate the reaction rate in the chemical reaction process, relatively high temperatures, such as 75˜85° C., can be maintained, and the solution is stirred continuously, such as at 1,000˜1,200 r/min, to increase the number of molecules colliding. 
         [0037]    The below table shows the saponification reference values calculated as the amount of sodium hydroxide needed in the saponification of oil. 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                   
               
               
                   
                   
                 Saponification value (Sodium 
                 Hardness Value 
               
               
                   
                 Kind of Oil 
                 hydroxide, NaOH) 
                 (INS Value) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Olive Oil 
                 0.134 
                 109 
               
               
                   
                 Coconut Oil 
                 0.190 
                 258 
               
               
                   
                 Palm Oil 
                 0.141 
                 145 
               
               
                   
                 Rice Bran Oil 
                 0.128 
                 70 
               
               
                   
                   
               
             
          
         
       
     
         [0038]    The saponification reaction equation may be described as follows: 
         [0000]    The chemical formula of triglyceride of is: 
         [0000]      CH 2 COOR—CHCOOR—CH 2 —COOR→C 3 H 5 (OCOR) 3 →RCOOR′.
 
         [0039]    According to an analysis of the chemical formula, it is obtained by three fatty acid molecules (R—COOH) and one glycerol molecule (C 3 H 5 (OH)). Therefore, the saponification reaction equation is: 
         [0000]      CH 2 COOR—CHCOOR—CH 2 —COOR+3NaOH         3R—COONa (sodium soap base)+CH 2 OH—CHOH—CH 2 OH (glycerol).
 
         [0040]    The R base may be different, but the R-COONa produced all can be saponified. The common R— includes: 
         [0041]    C17H33-: 8-heptadecenyl group and the R-COOH is oleic acid; 
         [0042]    C17H33-: n-pentadecyl group and the R-COOH is palmitic acid; and 
         [0043]    C17H35-: n-heptadecyl group and the R-COOH. 
         [0044]    Oleic acid is a monounsaturated fatty acid, and is obtained from the hydrolysis of oil; palmitic acid and stearic acid both are saturated fatty acids and are obtained from the hydrolysis of fat. 
         [0045]    The usage of the saponification function is as follows. The complex sodium-calcium soap grease has a role like that of an invisible sponge, to absorb a large amount of the grinding powder  2  and oil so as to go into a semisolid state, and it is both water and temperature resistant. Its drop point is about 150° C., and the temperature range of its use is 100˜130° C. Furthermore, the complex sodium-calcium soap grease has very good wear resistance, has a polar adhesive attraction to metal, and can form a wear resistant film with the quartz powder. However, the more the soap content, the harder the consistency. On the other hand, the less the soap content, the thinner the consistency. Therefore, if finished products with different consistencies are desired, the consistencies can be controlled by adjusting the soap content. 
         [0046]    Combining the most optimized parameters mentioned above, the saponification time can be shortened to 45 minutes, and the stirring is continued until the product is cooled to room temperature (a cooling system can be used to accelerate cooling). 
         [0047]    2. Adding a lot of the viscous grease agent (the white oil, the animal oil or the vegetable oil), and the grinding powder  2  which are evenly dispersed in the complex calcium-based soap grease, creates a semi-solid gel body (Gel). 
         [0048]    Step 1: the complex sodium-calcium soap grease is added to tank A, and stirred by a mixer at 100˜1,200 rpm and 80% of the viscous grease agent (the white oil, the animal oil or the vegetable oil) is added to tank B. 
         [0049]    Step 2: firstly, the additive is added to the viscous grease agent in tank B, and then the mixer starts stirring the two rapidly at 3,000˜4,000 rpm until the additive is completely dissolved. 
         [0050]    Step 3: the grinding powder  2  cannot be deliquesced and agglomerated, and should be removed with a sieve. 
         [0051]    Step 4: the solution in tank B following Step 2 is added slowly to the content of tank A at a speed of 10% of the total oil per minute and stirred continuously. When the oil is completely dissolved into a paste gel, the grinding powder  2  is added and stirred continuously to form a semi-solid gel body (Gel). 
         [0052]    Step 5: the semi-solid gel body (Gel) in tank A is fed helically into the feed chute of the automatic form-fill-seal packaging machine, to obtain the finished products of the grinding product for sharpening shredder blades. 
         [0053]    Part II. The steps of the manufacturing process for the grinding product in the form of a grinding sheet of the invention, to be used for sharpening shredder blades, may be as follows: 
         [0054]    With this manufacturing process, the grinding sheet for sharpening shredder blades, according to the invention, can be obtained, and its form of packaging can be a sealed package, as in the case if the powder form of the invention described above, and also as an unsealed package. Various environmental-friendly materials like paper, release liners, plastic film adhesive paper, powder agents and so on can be used between the grinding sheets to separate them. 
         [0055]    In a working environment, the room temperature is typically 20˜30° C., and the relative humidity is about 60˜70%. 
         [0056]    In the manufacturing process, the stearic acid is made from plant fat or animal fat, and placed, together with the white wax, the microcrystalline wax, and the PE wax, into a device with a temperature-adjustable, hot-kerosene recirculating, heater and a single-tank bi-directional variable speed mixing barrel. The temperature is set at 200° C. When the waxes in the tank are completely dissolved, the temperature is lowered to 150° C. The mixer then starts stirring at 1,000˜1,200 rpm, and the additive  3  is added. When the additive is completely dissolved, the grinding powder  2  is added through a sieve, and then the stirring speed is increased to 2,000˜2,500 rpm. After 15 minutes, the speed is lowered to 1,000˜1,200 rpm, and the temperature is further reduced to 120° C. The mixture is sent through an insulated air pressure transfer line to an ice water, recirculating cooling system that has a metal tank with a teflon surface, a cutting shear, and a variable speed motor transport unit. After cooling and cutting, the solid wax sheets with desired length and width can be obtained, and then sent to a planar automatic bag-forming machine to be packaged or both packaged and sealed, as single-sheet type or multi-sheet type grinding sheets. 
         [0057]    The bag-forming steps in the above mentioned manufacturing processes of Part I and Part II include moving and placing a whole roll of laminated plastic film on an automatic form-fill-seal packaging machine, and sending the grinding composition for sharpening shredder blades into the feed chute of the automatic form-fill-seal packaging machine, after adjusting both the amount of the grinding composition to fill the bag and the length and the width of the plastic packaging product. Also part of these processes are the steps of filling the bag with a certain amount of the grinding composition for sharpening shredder blades through the automatic form-fill-seal packaging machine, and making the finished products of the grinding product for sharpening shredder blades. 
         [0058]    To understand the technical content of the invention more clearly, the invention is further described by reference to the following exemplary embodiments. 
       Example 1 
       [0059]    The grinding powder  2  is 55 wt %, based on total weight of the composition hereinafter. The anti-rust powder is 5 wt %, the anti-wear powder is 2 wt %, the white oil is 35 wt %, the anti-static powder is 2 wt % and the anti-oxidation powder is 1 wt %. The grinding powder  2 , is natural diamond grinding powder, the anti-rust powder is aluminum distearate, the anti-static powder is glycerol monostearate, the anti-oxidation powder is butylated hydroxytoluene, the anti-wear powder is the complex sodium-calcium soap grease, and the manufacturing processes are described above in Part I. 
       Example 2 
       [0060]    The grinding powder  2  is 57 wt %, the anti-rust powder is 5 wt %, the stearin candle is 35 wt %, the anti-static powder is 2 wt % and the anti-oxidation powder is 1 wt % The grinding powder  2 , is natural diamond grinding powder, the anti-rust powder is aluminum distearate, the anti-static powder is glycerol monostearate, the anti-oxidation powder is butylated hydroxytoluene, the anti-wear powder is the complex sodium-calcium soap grease, and the manufacturing processes described above in Part II. 
       Example 3 
       [0061]    The grinding powder  2  is 51 wt %, the anti-rust powder is 15 wt %, the anti-wear powder is 6 wt %, the vegetable oil is 20 wt %, the anti-static powder is 6 wt % and the anti-oxidation powder is 2 wt % The grinding powder  2 , is natural quartz grinding powder, the anti-rust powder is aluminum distearate, the anti-static powder is glycerol monostearate, the anti-oxidation powder is butylated hydroxytoluene, the anti-wear powder is the complex sodium-calcium soap grease, and the manufacturing processes are described above in Part I. 
       Example 4 
       [0062]    The grinding powder  2  is 65 wt %, the anti-rust powder is 15 wt %, the anti-wear powder is 6 wt %, the white oil is 5 wt %, the anti-static powder is 6 wt % and the anti-oxidation powder is 3 wt %. The grinding powder  2 , is natural quartz grinding powder, the anti-rust powder is aluminum distearate, the anti-static powder is glycerol monostearate, the anti-oxidation powder is butylated hydroxytoluene, the anti-wear powder is the complex sodium-calcium soap grease, and the manufacturing processes are described above in Part I. 
       Example 5 
       [0063]    The grinding powder  2  is 64 wt %, the anti-rust powder is 1 wt %, the stearin candle is 33 wt %, the anti-static powder is 1 wt % and the anti-oxidation powder is 1 wt %. The grinding powder  2 , is natural diamond grinding powder, the anti-rust powder is aluminum distearate, the anti-static powder is glycerol monostearate, the anti-oxidation powder is butylated hydroxytoluene, the anti-wear powder is the microcrystalline wax in the stearin candle, and the manufacturing processes are described above in Part II. 
         [0064]    The grinding product for sharpening shredder blades of the invention is very simple to use. To use it, the grinding product is inserted directly into the paper inlet of the shredder, just like in the process of shredding paper. Therefore, it is very simple and convenient. When the rotating blades in the shredder cut the grinding product for sharpening shredder blades, the sealed bag  1  is cut open, due to the extrusion principle. The grinding powder  2  inside the bag will grind two sides of each of the high-speed rotating shredder blades to make them sharp, and with the functional additive  3 , it can coat the blades with anti-rust protective films, and enhance the anti-oxidation and anti-static functions of shredder blades. The grinding product can also maintain the shredders. After use, the grinding product will go into the ash-bin. 
         [0065]    The grinding product of the invention, can grind shredder blades to maintain the sharpness, and remove rusty spots, paper scraps, blemishes, etc. on the surface of the blades. The grinding product can prevent paper scraps and sundries from adhering to the blades, and prevent a dust explosion of the paper in the shredder closed chamber due to electric sparks produced by the motor or static. It can prevent oxidizing and rusting of the blades. When combined with the anti-rust agent, the grinding product has a dual effect: it can prevent the surface of the metal of shredder blades from wearing and scratching and reduce vibration noise, and it can form firm protective films on blades to extend the blade life. 
         [0066]    The invention can be used routinely and regularly to maintain the shredder blades of shredders, and can also be used according to the specific conditions of the shredder blades, such as, when the paper shredding is not very effective. Multiple grinding products for sharpening shredder blades can be used in one maintenance treatment. 
         [0067]    The grinding composition for sharpening shredder blades of the invention is easy and convenient to prepare and its raw materials are easy to obtain. The grinding sheet and grinding product manufactured from it, have simple structures, can grind shredder blades, are convenient to use, time-saving and labor-saving, and extend the operational life of shredders, reduce their operational cost, and are suitable for popularization and application on a large-scale. 
         [0068]    While the invention has been shown and described with particular reference to preferred embodiments thereof, it is 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 as defined by the claims. It is clearly understood therefore, that the same represents illustration and example only and is not to be taken as a limitation.