Abstract:
The present invention generally provides anti-microbial paper products, compositions comprising anti-microbial paper products, processes for producing anti-microbial paper products, and methods of inhibiting microbial growth or replication in paper products.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority from Provisional Application Ser. No. 60/723,651 filed on Oct. 5, 2005, which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention generally provides paper products comprising antimicrobial agents and processes for making paper products comprising antimicrobial agents. In particular, the antimicrobial agent typically comprises a substituted 1,2-dihydroquinoline compound.  
       BACKGROUND OF THE INVENTION  
       [0003]     Paper and paper products are attractive sources for the growth of bacteria, fungi, and molds. Antimicrobial agents have been applied to the surface of the paper product after manufacture. If the coating is compromised, however, the paper or paper product is not longer protected from microbial growth. Anti-microbial agents have also been added to the pulp during the paper making process, such that they are incorporated into the finished paper product. Generally, high concentrations of an antimicrobial agent must be added during manufacture to obtain substantial antimicrobial activity in the finished paper product. The use of high concentrations of antimicrobial agents not only increases the cost of manufacture, but may also introduce waste material that has to be treated before release into waterways, which further increases the cost of manufacture. There is a need, therefore, for alternative antimicrobial agents to provide protection to paper products. These anti-microbial agents should be effective at relatively low doses, should present no health and environmental concerns, and should not be cost prohibitive.  
       SUMMARY OF THE INVENTION  
       [0004]     One aspect of the invention provides a process of producing a paper product. The process comprises contacting a substituted 1,2-dihydroquinoline compound with a composition comprising pulp.  
         [0005]     Yet another aspect of the invention encompasses a method of inhibiting microbial growth or replication in a paper product. The method comprises contacting a paper product with a substituted 1,2-dihydroquinoline compound.  
         [0006]     A further aspect of the invention provides a paper product comprising paper and a substituted 1,2-dihydroquinoline compound.  
         [0007]     Another aspect of the invention encompasses a composition comprising a substituted 1,2-dihydroquinoline compound and pulp or pulp slurry. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0008]     It has been discovered that substituted 1,2-dihydroquinoline compounds function as anti-microbial agents when contacted with a paper product or when contacted with raw materials used in paper manufacturing. In a typical embodiment of the invention, the compound may be added during the paper manufacturing process, such as to pulp or pulp slurry, to inhibit microbial growth or replication in the paper manufacturing raw materials. Alternatively, the compound may be disposed within, on the surface, or within and on the surface of a paper product to inhibit microbial growth or replication on the paper product. The substituted 1,2-dihydroquinoline, when added to a paper product in an effective amount as illustrated in the examples, inhibits microbial growth and/or replication that could otherwise destroy the paper product or be harmful to the user of the paper product. Advantageously, the substituted 1,2-dihydroquinoline compounds also function as antioxidants, reducing oxidation of the paper product. Moreover, the substituted 1,2-dihydroquinolines are thermally stable at temperatures employed, and unlike some of the existing mold proofing agents used by the paper industry, they do not decompose or undergo the reaction of pyrolysis during paper and pulp processing, for example, drying and in a preferred embodiment; the compounds do not cause discoloration of the paper products.  
         [0000]     I. Paper Products Having Substituted 1,2-Dihydroquinoline Compounds  
         [0009]     One aspect of the present invention provides paper products having substituted 1,2-dihydroquinoline compounds. Substituted 1,2-dihydroquinoline compounds suitable for use in the invention generally correspond to formula (I):  
                         
 
         [0010]     wherein: 
        R 1 , R 2 , R 3  and R 4  are independently selected from the group consisting of hydrogen and an alkyl group having from 1 to about 6 carbons;     R 5  is an alkoxy group having from 1 to about 12 carbons.        
 
         [0013]     In another embodiment, the substituted 1,2-dihydroquinoline will have formula (I) wherein: 
        R 1 , R 2 , R 3  and R 4  are independently selected from the group consisting of hydrogen and an alkyl group having from 1 to about 4 carbons; and     R 5  is an alkoxy group having from 1 to about 4 carbons.        
 
         [0016]     In one preferred embodiment, the substituted 1,2-dihydroquinoline will be 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline having the formula:  
                         
 
         [0017]     6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, commonly known as ethoxyquin, is sold under the trademark SANTOQUIN®. The present invention also encompasses salts of ethoxyquin and other compounds having formula (I). Ethoxyquin and other compounds having formula (I) may be purchased commercially from Novus International, Inc. or made in accordance with methods generally known in the art, for example, as detailed in U.S. Pat. No. 4,772,710, which is hereby incorporated by reference in its entirety.  
         [0018]     Typically, in each embodiment described herein, the substituted 1,2-dihydroquinoline compound may be formulated as a liquid, powder or emulsion and contacted with the paper product. A suitable example of an emulsion formulation comprises approximately 70% by weight 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, approximately 23% by weight water, approximately 5% by weight Tween and approximately 2% by weight myverol 18-19.  
         [0019]     As will be appreciated by a skilled artisan, the technique for contacting the substituted 1,2-dihydroquinoline compound with the paper product can and will vary, depending upon the paper product and its manufacturing process. In one embodiment, the substituted 1,2-dihydroquinoline compounds may be incorporated into the paper product during its original manufacture. According to one alternative of this embodiment, the substituted 1,2-dihydroquinoline is typically contacted with at least one raw material in the paper manufacturing process, such as pulp or a mixture of pulp and water (“pulp slurry”) to minimize spoilage of the paper, pulp or pulp slurry. Depending upon the embodiment, the pulp may be produced from a chemical pulping method or from a mechanical pulping method. The paper product of the invention is formed from the pulp slurry by extracting water from the slurry to form a paper web comprising paper fibers having interstices. Water may be removed from the pulp slurry according to generally known methods, for example, by applying negative pressure (vacuum) or heat.  
         [0020]     In another embodiment, the substituted 1,2-dihydroquinoline compounds may be contacted with the paper product contemporaneously as the interstices are formed. In this embodiment, the paper web having interstices may be passed through a size press, according to methods known in the art. The size press will typically comprise two squeeze rollers between which the paper web is passed. As a part of the process, a composition comprising a substituted 1,2-dihydroquinoline compound and water or another suitable aqueous carrier, is dispensed, for example, through hoses emanating from one or more tanks and directed between the squeeze rollers. The squeeze rollers generally have a gap between them that defines the thickness of the paper web. As such, by setting the gap to a size equal to or smaller as compared to the thickness of the paper web, the substituted 1,2-dihydroquinoline compound may be forced into the interstices of the paper fibers. Penetration and distribution of the substituted 1,2-dihydroquinoline compound is achieved throughout a substantial portion of the thickness of the paper. After passing the paper web through the sizing press, the paper web incorporated with the substituted 1,2-dihydroquinoline compound, may be passed over a heated drying drum to evaporate the remaining water. The paper product is then ready for production into a variety of products, as described in detail below.  
         [0021]     Alternatively, the substituted 1,2-dihydroquinoline compound may be contacted with the paper product after its manufacture. For example, the paper product may be lightly dampened with a solution comprising the substituted 1,2-dihydroquinoline compound, and then allowed to dry. Typically, this process leaves the substituted 1,2-dihydroquinoline compound disposed on the surface of the paper product.  
         [0022]     Irrespective of when the substituted 1,2-dihydroquinoline compound is added in the paper manufacturing process, it is typically added to the paper product in an anti-microbial effective amount. The amount of substituted 1,2-dihydroquinoline that constitutes an “anti-microbial effective amount” can and will vary depending upon several factors, such as, the type of paper product, the microbial target, and the degree of anti-microbial activity desired. Generally speaking when the substituted 1,2-dihydroquinoline is disposed within or on the surface of the paper product, as illustrated in the examples, an effective amount is a concentration of at least 250 ppm and more typically, at least 300 ppm. In another embodiment, the substituted 1,2-dihydroquinoline compound is added to the paper product at a concentration from about 250 ppm to about 1000 ppm. In another embodiment, the substituted 1,2-dihydroquinoline compound is added to the paper product at a concentration from about 400 ppm to about 600 ppm. Stated another way, the substituted 1,2-dihydroquinoline compound is typically added to the paper product at a concentration of at least 0.1% by weight. In a further embodiment, the substituted 1,2-dihydroquinoline compound is added at a concentration from about 0.1% to about 5% by weight. Alternatively, when the substituted 1,2-dihydroquinoline is added to a raw material during the paper manufacturing process, typically it is added at a concentration of about 50 ppm to about 6000 ppm.  
         [0023]     A variety of paper products are encompassed by the present invention, including paper and paperboard. The paper product may be used to store and communicate information. For example, the paper product may be newsprint, magazine paper, book paper, printing paper or writing paper. The paper product may be used to transport and protect food, such as, packaging, sacks, tetra packs, paper towels, and paper plates and cups. Alternatively, the paper product may be used for personal hygiene. For example, the paper product may be tissues, toilet paper, feminine products, and diapers. The paper product may be used for packaging materials and products. In this application, the paper may be paperboard used in the manufacture of corrugated board, folding boxboard, and wrapping. The paper product may be used to make specialized papers, such as, monetary currency, cigarette papers and filter papers, as well as gypsum liners and special papers for waxing, insulating, roofing, and asphalting.  
         [0024]     The previous discussion has focused on paper products, but the invention can also be used with similar materials having non-wood based fiber construction. For example, the substituted 1,2-dihydroquinoline may be contacted with several types of non-wood fibers to inhibit microbial growth and/or replication. Non-wood fibers can include fibers woven and nonwoven from wood, plants and/or other textile fibers including but not limited to Aramid (Nomex/Kevlar) Conductive Nylon (Polyolefin), Nylon (Bi-component side by side sheath core), Cotton, Rayon, Wool, Local and Modacrylic (Fusible co-Pet fiber) ground to its individual constituents or treated chemically, by digestion with acidic or basic liquors, to form Cellulose, the main fibrous component most suited for making paper goods. It will be apparent to those skilled in the art that impregnating a fibrous material, particularly a fibrous sheet material such as paper, will allow for the anti-microbial properties of the impregnating material to be added to the physical properties of the fibrous material.  
         [0000]     II. Additional Agents  
         [0025]     Another aspect of the invention comprises a paper product having a substituted 1,2-dihydroquinoline compound and at least one additional agent. Typically, the agent is selected from the group consisting of a surfactant, an anti-microbial, an antioxidant, a slimicide, and a protected or microencapsulated 2-hydroxy-4-methylthiobutanoic acid, i.e., hydroxy analog of methionine. The agent may be contacted with the paper product contemporaneously with the substituted 1,2-dihydroquinoline compound. Alternatively, the agent may be contacted with the paper product either before or after the substituted 1,2-dihydroquinoline compound is contacted with the paper product. The agent may be contacted with the paper product during its manufacture or after its manufacture according to any method known in the art or as detailed herein.  
         [0000]     (a) surfactants  
         [0026]     Suitable surfactants for use in combination with the substituted 1,2-dihydroquinoline compound include cationic surfactants, non-ionic surfactants and combinations thereof. For example, the surfactant may be selected from the group consisting of ethoxylated sorbitans, ethoxylated fatty acids, polysorbate-80, glycerol oleate, oleate salts, coconate salts, laurelate salts and combinations thereof. Suitable combinations of a substituted 1,2-dihydroquinoline compound and a surfactant are illustrated in Table A.  
                           TABLE A                                   First Compound   Second Compound                           Ethoxyquin   ethoxylated sorbitans           Ethoxyquin   ethoxylated fatty acids           Ethoxyquin   polysorbate-80           Ethoxyquin   glycerol oleate           Ethoxyquin   oleate salts           Ethoxyquin   coconate salts           Ethoxyquin   laurelate salts           Ethoxyquin   combinations thereof                      
 
 (b) anti-microbial agents 
 
         [0027]     Several anti-microbial agents are suitable for use in combination with the substituted 1,2-dihydroquinoline compound. Typically the anti-microbial agent selected is an agent that acts synergistically with the anti-microbial activity of the substituted 1,2-dihydroquinoline compound. In this context, “synergistically” includes not only those anti-microbial agents that enhance the anti-microbial activity of the substituted 1,2-dihydroquinoline compound, but also anti-microbial agents that inhibit at least one or more microbes of a different spectrum. In one embodiment, the anti-microbial agent is selected from the group consisting of halogenated salicylanilides, halogenated carbanilides, alkylbenzoylacrylates, thiuram sulfides, quaternary ammonium compounds, halogenated anilides of thiophene carboxylic acids, chlorohexidines, dithiocarbamates, halogenated bisphenols, halogenated diphenyl ethers, and antibiotics. Examples of suitable halogenated salicylanilides include: 5-bromo-salicylanilide; 4′,5-dibromo-salicylanilide; 3,4′,5-tribromo-salicylanilide; 6-chloro-salicylanilide; 4′5-dichloro-salicylanilide; 3,4′5-trichloro salicylanilide; 4′,5-diiodo-salicylanilide; 3,4′,5-triiodo-salicylanilide; 5-chloro-3′-trifluoromethyl-salicylanilide; 5-chloro-2′-trifluoromethyl-salicylanilide; 3,5-dibromo-3′-trifluoromethyl-salicylanilide; 3-chloro-4-bromo-4′-trifluoromethyl-salicylanilide; 2′,5-dichloro-3-phenyl-salicylanilide; 3′,5-dichloro-4′-methyl-3-phenyl-salicylanilide; 3′,5-dichloro-4′phenyl-3-phenyl-salicylanilide; 3,3′,5-trichloro-6′-(p-chlorophenoxy)-salicylanilide; 3′,5-dichloro-5′-(p-bromophenoxy)-salicylanilide; 3,5-dichloro-6′-phenoxy-salicylanilide; 3,5-dichloro-6′-(o-chlorophenoxy)-salicylanilide; 5-chloro-6′-(o-chlorophenoxy)-salicylanilide; 5-chloro-6′-beta-naphthyloxy-salicylanilide; 5-chloro-6′-alpha-naphthyloxy-salicylanilide; and 3,3′,4-trichloro-5,6′-beta naphthyloxy-salicylanilide. By way of non-limiting example, suitable halogenated carbanilides include: 3,4,4′-trichloro-carvanilide, the 3,3′,4-trichloro derivatives, and 3-trifluoromethyl-4,4′-dichlorocarbanilide. Examples of suitable bis-phenols are represented by the following: 2,2′-methylenebis(4-chlorophenol); 2,2′-methylenebis(4,5-dichlorophenol); 2,2′-methylenebis(3,4,6-trichlorophenol); 2,2′-thiobis(4,6-dichlorophenol); 2,2′-diketobis(4-bromophenol); 2,2′-methylenebis(4-chloro-6-isopropylphenol); and 2,2′-isopropylidenebis(6-sec-butyl-4-chlorophenol). Examples of suitable quaternary ammonium compounds are: diisobutylphenoxyethoxyethyldimethylbenzylammonium chloride; N-methyl-N-(2-hydroxyethyl)—N-(2-hydroxydodecyl)-N-benzyl ammonium chloride; Cetyl trimethylammonium bromide; Stearyl trimethylammonium bromide; Oleyl dimethylethylammonium bromide; Lauryidimethylchlorethoxyethylammonium chloride; Luryidimethylchlorethoxyethylammonium chloride; Alkyl(C8-C18)dimethyl(3,4-dichlorobenzyl)-ammonium chloride; Lauryl pyridinium bromide; Lauryl isoquinolinium bromide; and N(lauroyloxyethylaminoformylmethyl)pyridinium chloride. Examples of suitable thiocarbamates and the thiuram sulfides include: Dsodium ethylene bis-dithiocarbamate (Nabam); Dammonium ethylene bis-dithiocarbamate(amabam); Zn ethylene bis-dithiocarbamate (ziram); Fe ethylene bis-dithiocarbamate (ferbam); Mn ethylene bis-dithiocarbamate (manzate); Tramethyl thiuram disulfide; Ttrabenzyl thiuram disulfide; Ttraethyl thiura, disulfide; and Ttramethyl thiuram sulfide. In another embodiment, the anti-microbial agent is selected from the group consisting of 2-bromo-2-nitropropane-1,3-diol (sold under the trademark Myacide® AS); 1,5-pentanedial (sold under the trademark Protectol® GA 50); tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione (sold under the trademark Protectol® DZ; and 1,3,5-tris-(2-hydroxyethyl)-1,3,5-hexahydrotriazine (sold under the trademark Protectol® HT). Suitable combinations of a substituted 1,2-dihydroquinoline compound and an additional anti-microbial agent are illustrated in Table B.  
                   TABLE B                       First Compound   Second Compound                   substituted 1,2-   halogenated salicylanilides       dihydroquinoline       compound       substituted 1,2-   halogenated carbanilides       dihydroquinoline       compound       substituted 1,2-   alkylbenzoylacrylates       dihydroquinoline       compound       substituted 1,2-   thiuram sulfides       dihydroquinoline       compound       substituted 1,2-   quaternary ammonium compounds       dihydroquinoline       compound       substituted 1,2-   halogenated anilides of thiophene       dihydroquinoline   carboxylic acids       compound       substituted 1,2-   chlorohexidines       dihydroquinoline       compound       substituted 1,2-   dithiocarbamates       dihydroquinoline       compound       substituted 1,2-   halogenated bisphenols       dihydroquinoline       compound       substituted 1,2-   halogenated diphenyl ethers       dihydroquinoline       compound       substituted 1,2-   antibiotics       dihydroquinoline       compound       Ethoxyquin   5-bromo-salicylanilide       Ethoxyquin   4′,5-dibromo-salicylanilide       Ethoxyquin   3,4′,5-tribromo-salicylanilide       Ethoxyquin   6-chloro-salicylanilide       Ethoxyquin   4′5-dichloro-salicylanilide       Ethoxyquin   3,4′5-trichloro-salicylanilide       Ethoxyquin   4′,5-diiodo-salicylanilide       Ethoxyquin   3,4′,5-triiodo-salicylanilide       Ethoxyquin   5-chloro-3′-trifluoromethyl-salicylanilide       Ethoxyquin   5-chloro-2′-trifluoromethyl-salicylanilide       Ethoxyquin   3,5-dibromo-3′-trifluoromethyl-salicylanilide       Ethoxyquin   3-chloro-4-bromo-4′-trifluoromethyl-salicylanilide       Ethoxyquin   2′,5-dichloro-3-phenyl-salicylanilide       Ethoxyquin   3′,5-dichloro-4′-methyl-3-phenyl-salicylanilide       Ethoxyquin   3′,5-dichloro-4′phenyl-3-phenyl-salicylanilide       Ethoxyquin   3,3′,5-trichloro-6′-(p-chlorophenoxy)-salicylanilide       Ethoxyquin   3′,5-dichloro-5′-(p-bromophenoxy)-salicylanilide       Ethoxyquin   3,5-dichloro-6′-phenoxy-salicylanilide       Ethoxyquin   3,5-dichloro-6′-(o-chlorophenoxy)-salicylanilide       Ethoxyquin   5-chloro-6′-(o-chlorophenoxy)-salicylanilide       Ethoxyquin   5-chloro-6′-beta-naphthyloxy-salicylanilide       Ethoxyquin   5-chloro-6′-alpha-naphthyloxy-salicylanilide       Ethoxyquin   3,3′,4-trichloro-5,6′-beta-naphthyloxy-salicylanilide       Ethoxyquin   3,4,4′-trichloro-carvanilide       Ethoxyquin   3,3′,4-trichloro derivatives       Ethoxyquin   3-trifluoromethyl-4,4′-dichlorocarbanilide       Ethoxyquin   2,2′-methylenebis(4-chlorophenol)       Ethoxyquin   2,2′-methylenebis(4,5-dichlorophenol)       Ethoxyquin   2,2′-methylenebis(3,4,6-trichlorophenol)       Ethoxyquin   2,2′-thiobis(4,6-dichlorophenol)       Ethoxyquin   2,2′-diketobis(4-bromophenol)       Ethoxyquin   2,2′-methylenebis(4-chloro-6-isopropylphenol)       Ethoxyquin   2,2′-isopropylidenebis(6-sec-butyl-4-chlorophenol)       Ethoxyquin   diisobutylphenoxyethoxyethyidimethyl-           benzylammonium chloride       Ethoxyquin   N-methyl-N-(2-hydroxyethyl)-N-(2-hydroxydodecyl)-           N-benzyl ammonium chloride       Ethoxyquin   Cetyl trimethylammonium bromide       Ethoxyquin   Stearyl trimethylammonium bromide       Ethoxyquin   Oleyl dimethylethylammonium bromide       Ethoxyquin   Lauryidimethylchlorethoxyethylammonium chloride       Ethoxyquin   Luryidimethylchlorethoxyethylammonium chloride       Ethoxyquin   Alkyl(C8-C18)dimethyl(3,4-dichlorobenzyl)-           ammonium chloride       Ethoxyquin   Lauryl pyridinium bromide       Ethoxyquin   Lauryl isoquinolinium bromide       Ethoxyquin   N(lauroyloxyethylaminoformylnethyl)pyridinium           chloride       Ethoxyquin   Dsodium ethylene bis-dithiocarbamate (Nabam)       Ethoxyquin   Dammonium ethylene bis-dithiocarbamate(amabam)       Ethoxyquin   Zn ethylene bis-dithiocarbamate (ziram)       Ethoxyquin   Fe ethylene bis-dithiocarbamate (ferbam)       Ethoxyquin   Mn ethylene bis-dithiocarbamate (manzate)       Ethoxyquin   Tramethyl thiuram disulfide       Ethoxyquin   Ttrabenzyl thiuram disulfide       Ethoxyquin   Ttraethyl thiura, disulfide       Ethoxyquin   Ttramethyl thiuram sulfide       Ethoxyquin   2-bromo-2-nitropropane-1,3-diol (sold under the           trademark Myacide ® AS)       Ethoxyquin   1,5-pentanedial (sold under the trademark           Protectol ® GA 50)       Ethoxyquin   tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione           (sold under the trademark Protectol ® DZ)       Ethoxyquin   1,3,5-tris-(2-hydroxyethyl)-1,3,5-hexahydrotriazine           (sold under the trademark Protectol ® HT)                  
 
 (c) Antioxidants 
 
         [0028]     Several antioxidant agents are suitable for use in combination with the substituted 1,2-dihydroquinoline compound. Suitable antioxidant agents are typically included to reduce degradation or deterioration of the paper product. For example, the antioxidant may be selected from the group consisting of trialkyl phosphites, mixed alkyl/aryl phosphites, alkylated aryl phosphites, sterically hindered aryl phosphites, aliphatic spirocyclic phosphites, sterically hindered phenyl spirocyclics, sterically hindered bisphosphonites, hydroxyphenyl propionates, hydroxy benzyls, alkylidene bisphenols, alkyl phenols, aromatic amines, thioethers, hindered amines, hydroquinones and mixtures thereof. Alternatively, the antioxidant may be any of the antioxidants delineated in the Examples, such as, alpha-lipoic acid, alpha-tocopherol, alpha-tocopherol acetate, ascorbic acid, ascorbyl palmitate, beta-propiolactone, BHA, BHT, carvone, cinnamaldehyde, citral, decanal, dehydroacetic acid, delta-tocopherol, diacetyl, dilauryl thiodipropionate, dodecyl gallate, eugenol, gallic acid, limonene, octyl gallate, oregano oil, piperonal, propyl gallate, stearyl citrate, TBHQ, and vanillin. Suitable combinations of a substituted 1,2-dihydroquinoline compound and an additional antioxidant are illustrated in Table C.  
                   TABLE C                       First Compound   Second Compound                   substituted 1,2-dihydroquinoline   trialkyl phosphites       compound       substituted 1,2-dihydroquinoline   mixed alkyl/aryl phosphites       compound       substituted 1,2-dihydroquinoline   alkylated aryl phosphites       compound       substituted 1,2-dihydroquinoline   sterically hindered aryl       compound       substituted 1,2-dihydroquinoline   phosphites aliphatic spirocyclic       compound   phosphites       substituted 1,2-dihydroquinoline   sterically hindered phenyl spirocyclics       compound       substituted 1,2-dihydroquinoline   sterically hindered bisphosphonites       compound       substituted 1,2-dihydroquinoline   hydroxyphenyl propionates       compound       substituted 1,2-dihydroquinoline   hydroxy benzyls       compound       substituted 1,2-dihydroquinoline   alkylidene bisphenols       compound       substituted 1,2-dihydroquinoline   alkyl phenols       compound       substituted 1,2-dihydroquinoline   aromatic amines       compound       substituted 1,2-dihydroquinoline   thioethers       compound       substituted 1,2-dihydroquinoline   hindered amines       compound       substituted 1,2-dihydroquinoline   Hydroquinones       compound       Ethoxyquin   alpha-lipoic acid       Ethoxyquin   alpha-tocopherol       Ethoxyquin   alpha-tocopherol acetate       Ethoxyquin   ascorbic acid       Ethoxyquin   ascorbyl palmitate       Ethoxyquin   beta-propiolactone       Ethoxyquin   BHA       Ethoxyquin   BHT       Ethoxyquin   carvone       Ethoxyquin   Cinnamaldehyde       Ethoxyquin   citral       Ethoxyquin   decanal       Ethoxyquin   dehydroacetic acid       Ethoxyquin   delta-tocopherol       Ethoxyquin   diacetyl       Ethoxyquin   dilauryl thiodipropionate       Ethoxyquin   dodecyl gallate       Ethoxyquin   eugenol       Ethoxyquin   gallic acid       Ethoxyquin   limonene       Ethoxyquin   octyl gallate       Ethoxyquin   oregano oil       Ethoxyquin   piperonal       Ethoxyquin   propyl gallate       Ethoxyquin   stearyl citrate       Ethoxyquin   TBHQ       Ethoxyquin   vanillin                  
 
         [0029]     As will be appreciated by the skilled artisan, any of the surfactants, anti-microbials, or antioxidants may be combined, either alone or in combination with one another, with the substituted 1,2-dihydroquinoline to form a composition of the invention. The concentration of these agents will depend upon the application but, in general, will be between about 0.0001% and about 10% by weight of the paper product, more preferably between about 0.001% and about 7.5%, most preferably between about 0.01% and about 5%.  
         [0000]     (d) Slimicides  
         [0030]     A variety of slimicides are suitable for use in combination with the substituted 1,2-dihydroquinoline compound. Suitable examples of slimicides include Acticide® DW, HF, SPX (from Thor, Inc. known under the isothiazolin family of products such as DCOIT, BIT, CIT etc.); Dantochlor® and Dantobrom® PG granular of briquette from Lonza, Inc. (known as halogenated hydantoin, e.g., 1-bromo-3-chloro-5,5-dimethylhydantoin and/or 1,3-dichloro 5,5 dimethyl hydantoin and/or 1,3-dichloro-5-ethyl-5methyl hydantoin); Paxgard® BD20, BD88, BKC, EM, MBT from Pax Chem, Inc. (known as 2-bromo-2-nitropropane-1,3 diol, alkyl dimethyl benzyl ammonium chloride, hexahydro-1,3,5-tris (2-hydroxyethyl)-s-triazine, methylenebisisothiocyanate etc); Paxgard® BSL, BU 30L, BU 30, BU 60, MB 10, TC; Busan® 1223 from Buckmann Lab.; Metasol® CB-220, CB-225AD, CB-225 L.C, CMI-150 from Ondeo-Nalco, Inc. (known as tripropyleneglycol monomethyl ether (80%) and 1,2 dibromo 2,4-dicyanobutane (20%), (25%), CMIT and MIT at 1.15% and 0.35% respectively). Generally, the ratio of substituted 1,2-dihydroquinoline to any of the slimicides referenced herein can and will vary. By way of non-limiting example, the ratio 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline to slimicide may vary from 0.05 to 99% by weight. Suitable combinations of a substituted 1,2-dihydroquinoline compound and a slimicide are illustrated in Table D.  
                           TABLE D                                   First Compound   Second Compound                           Ethoxyquin   Acticide ®           Ethoxyquin   Dantochlor ®           Ethoxyquin   Dantobrom ®           Ethoxyquin   1-bromo-3-chloro-5,5-dimethylhydantoin           Ethoxyquin   1,3-dichloro 5,5 dimethyl hydantoin           Ethoxyquin   1,3-dichloro-5-ethyl-5methyl hydantoin)           Ethoxyquin   2-bromo-2-nitropropane-1,3 diol, alkyl               dimethyl benzyl ammonium chloride           Ethoxyquin   hexahydro-1,3,5-tris (2-hydroxyethyl)-s-               triazine           Ethoxyquin   methylenebisisothiocyanate           Ethoxyquin   tripropyleneglycol monomethyl ether                      
 
 (e) Hydroxyl Analog of Methionine 
 
         [0031]     The substituted 1,2-dihydroquinoline compound may be combined with a protected or microencapsulated 2-hydroxy 4-methylthio butanoic acid (HMTBA), i.e., hydroxyl analog of methionine. Suitable hydroxyl analogs of methionine include 2-hydroxy-4(methylthio)butanoic acid (sold by Novus International, St. Louis, Mo. under the trade name Alimet®), its salts, esters, amides, and oligomers. Representative salts of HMTBA include the ammonium salt, the stoichiometric and hyperstoichiometric alkaline earth metal salts (e.g., magnesium and calcium), the stoichiometric and hyperstoichiometric alkali metal salts (e.g., lithium, sodium, and potassium), and the stoichiometric and hyperstoichiometric zinc salt. Representative esters of HMTBA include the methyl, ethyl, 2-propyl, butyl, and 3-methylbutyl esters of HMTBA. Representative amides of HMTBA include methylamide, dimethylamide, ethylmethylamide, butylamide, dibutylamide, and butylmethylamide. Representative oligomers of HMTBA include its dimers, trimers, tetramers and oligomers that include a greater number of repeating units.  
         [0032]     Alternatively, the hydroxy analog of methionine may be a metal chelate comprising one or more ligand compounds comprising HMTBA together with one or more metal ions. Irrespective of the embodiment, suitable non-limiting examples of metal ions include zinc ions, copper ions, manganese ions, iron ions, chromium ions, cobalt ions, and calcium ions. In one embodiment, the metal ion is divalent. Examples of divalent metal ions (i.e., ions having a net charge of  + 2) include copper ions, manganese ions, chromium ions, calcium ions, cobalt ions and iron ions. In another embodiment, the metal ion is zinc. In yet another embodiment, the metal ion is copper. In still another embodiment, the metal ion is manganese. In one exemplary embodiment, the metal chelate is HMTBA-Mn. In a further exemplary embodiment, the metal chelate is HMTBA-Cu. In an alternative exemplary embodiment, the metal chelate is HMTBA-Zn.  
         [0033]     As will be appreciated by a skilled artisan, the ratio of ligands to metal ions forming a metal chelate compound can and will vary. Generally speaking, a suitable ratio of ligand to metal ion is from about 1:1 to about 3:1 or higher. In another embodiment, the ratio of ligand to metal ion is from about 1.5:1 to about 2.5:1. Of course within a given mixture of metal chelate compounds, the mixture will include compounds having different ratios of ligand to metal ion. For example, a composition of metal chelate compounds may have species with ratios of ligand to metal ion that include 1:1, 1.5:1, 2:1, 2.5:1, and 3:1. Metal chelate compounds of the invention may be made in accordance with methods generally known in the art, such as described in U.S. Pat. Nos. 4,335,257 and 4,579,962, which are both hereby incorporated by reference in their entirety.  
         [0034]     Suitable combinations of a substituted 1,2-dihydroquinoline compound and HMTBA are illustrated in Table E.  
                           TABLE E                                   First Compound   Second Compound                           substituted 1,2-dihydroquinoline   HMTBA           compound           substituted 1,2-dihydroquinoline   HMTBA-Cu           compound           substituted 1,2-dihydroquinoline   HMTBA-Zn           compound           substituted 1,2-dihydroquinoline   HMTBA-Mn           compound           Ethoxyquin   HMTBA           Ethoxyquin   HMTBA-Cu           Ethoxyquin   HMTBA-Zn           Ethoxyquin   HMTBA-Mn                      
 
         [0035]     In one preferred embodiment, as detailed above, the HMTBA is HMTBA-Cu. A preferred composition comprises from about 30% to about 40% by weight 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, from about 1% to about 5% by weight HMTBA-Cu, and from about 55% to about 65% propylene glycol. In a more preferred embodiment, the composition comprises about 37% by weight 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, about 2% by weight HMTBA-Cu, and about 60% by weight propylene glycol.  
         [0000]     Definitions  
         [0036]     “Anti-microbial” is an agent that prevents or inhibits the growth, replication or growth and replication of a microorganism.  
         [0037]     “Microbial” or “microbe” is used in its broadest sense to encompass several diverse types of microorganisms, such as, fungi, yeast, bacteria, virus, and mildew, that grow and/or replicate during paper manufacturing or on the finished paper product. Generally, aerobic slime-forming bacteria, such as,  Pseudomonas, Klebsiella, Enterobacter  and  Bacillus , are problematic during the paper manufacturing process. Problematic anerobic microorganisms include  Desulphovibrio . In addition, problematic yeast and fungi include  Candida, Saccharomyces , and  Aspergillus.    
         [0038]     “Paper” is used in its broadest sense to encompass a substance composed of fibers interlaced into a compact web, which can be macerated into pulp, dried and pressed.  
         [0039]     PPM Stands for Parts Per Million.  
       EXAMPLES  
       [0040]     Examples 1 and 2 demonstrate the ability of a composition comprising ethoxyquin to inhibit microbial growth on paper products. Example 3 demonstrates the antimicrobial properties of antioxidants and other agents.  
         [0041]     Several of the compounds detailed in Table 1, 2, and 3 presented below are commercially available from Novus International, Saint Louis, Mo. (i.e., the composition abbreviated Santoquin is ethoxyquin, Biox AUSD is a blend of organic acid, inorganic acid and HMTBA and is sold under the trade name ACTIVATE® US WD; the compound abbreviated is HMBTA-Cu and is sold under the trade name MINTREX® Cu; and the compound abbreviated Tox-Guard dry is an antioxidant blend sold under the trade name TOXGUARD).  
       Example 1  
     Fungal Resistance Testing of Several Biocides  
       [0042]     Five different biocides at varying concentrations were tested for fungal resistance using the ASTM D 2020 Standard Test Method for Mildew (Fungus) Resistance of Paper and Paperboard protocol. This test method was designed for the qualitative determination of mildew (fungus) resistance of paper and paperboard, particularly those types that have been given a fungus resistant treatment. Specific test conditions applied to this project are described below, but at all times the ASTM D 2020 test protocol was strictly followed.  
         [0043]     All five biocides (Santoquin®, HMTBA-Cu, BIOX-AUSD, Tox-Guard*Dry, and Metasol-TK 100) were tested at three different concentrations (200, 400, and 600 ppm). Santoquin®, HMTBA-Cu, and BIOX-AUSD were diluted in dimethyl sulfoxide (DMSO), while Tox-Guard*Dry and Metasol-TK100 were diluted in water. DMSO was used a control diluent. The fungal inoculum was comprised of three different species:  Aspergillus niger  ATCC 9642,  Aspergillus flavus  ATCC 9643, and Chaetomium globosum ATCC 6205.  
         [0044]     Glass fiber filter paper was treated with the individual test biocides at the respective concentrations listed in Table 1 and allowed to dry overnight. The filter paper carriers, tested in triplicate, were placed in Petri dishes on mineral salts agar and inoculated with the fungal inoculum. The samples were incubated at 28° C. for 2 weeks and examined daily during the first week of incubation for the growth of the test organisms.  
         [0045]     If a sample showed growth of test organisms after seven days of incubation, the test was discontinued and the sample was reported as fungus non-resistant. If no growth was observed on a sample after the first week of incubation, the sample was incubated for an additional seven days. If, after two weeks, the sample showed growth of the test fungi, the sample was considered fungus non-resistant. If, after two weeks, there was no detectable growth of test organisms, the sample was considered fungus resistant.  
         [0046]     As delineated in Table 1, the samples treated with Metasol-TK 100 showed no growth at the end of the two weeks. Therefore, the Metasol-TK 100 treated samples were found to be fungal resistant in the ASTM D 2020 test at all three concentrations (200, 400, and 600 ppm). Similarly, the samples treated with 400 and 600 ppm Santoquin® showed no fungal growth at the end of two weeks. Therefore, the Santoquin® treated samples were found to be fungal resistant at 400 and 600 ppm. Comparatively, all concentrations of Tox-Guard*Dry, all concentrations of BIOX-AUSD, all concentrations of HMTBA-Cu, and Santoquin® at 200 ppm showed fungal growth, and therefore these samples were labeled fungus non-resistant.  
       Example 2  
     Fungal Resistance Testing of Santoquin  
       [0047]     One biocide sample, labeled Santoquin® was tested for fungal resistance using the ASTM D 2020 Standard Test Method for Mildew (Fungus) Resistance of Paper and Paperboard protocol. This test method was designed for the qualitative determination of mildew (fungus) resistance of paper and paperboard, particularly those types that have been given a fungus resistant treatment. Specific test conditions applied to this project are described below, but at all times the ASTM D 2020 test protocol was strictly followed.  
         [0048]     The Santoquin® biocide was diluted with DMSO and tested at two different concentrations: 0.1% and 1.0%. The biocide Kathon 893 was diluted to 0.1% and 1.0% in water and used as a control biocide. DMSO was used as a control diluent. The fungal inoculum was comprised of three different species:  Aspergillus niger  ATCC 9642,  Aspergillus flavus  ATCC 9643, and Chaetomium globosum ATCC 6205.  
         [0049]     Glass fiber filter paper was treated with two different concentrations (0.1% and 1.0%) of Santoquin® and allowed to dry overnight. The filter paper carriers, tested in triplicate, were placed in Petri dishes on mineral salts agar and inoculated with the fungal inoculum. The samples were incubated at 28° C. for 2 weeks and examined daily during the first week of incubation for the growth of the test organisms.  
         [0050]     If a sample showed growth of test organisms after seven days of incubation, the test was discontinued and the sample was reported as fungus non-resistant. If no growth was observed on a sample after the first week of incubation, the sample was incubated for an additional seven days. If, after two weeks, the sample showed growth of the test fungi, the sample was considered fungus non-resistant. If, after two weeks, there was no detectable growth of test organisms, the sample was considered fungus resistant.  
         [0051]     As delineated in Table 2, the samples treated with Santoquin® showed no fungal growth at the end of the two weeks. Therefore, the Santoquin® treated samples were found to be fungal resistant in the ASTM D 2020 test at both concentrations (0.1% and 1.0%) tested. Comparatively, both concentrations of Kathon 893 and the control diluent showed fungal growth and therefore these samples were labeled non-fungus resistant.  
       Example 3  
     Fungal Resistance Testing of Other Agents  
       [0052]     The antifungal properties of other agents were tested using an in vitro disk assay (Higgins and Brinkhaus, 1999, J. Appl. Poultry Res. 8:480-487). In this assay, paper disks were soaked in a fungal solution and placed on the surface of agar plates containing different concentration of the test agent. The radius of fungal growth radiating from each disk was considered indicative of the degree of inhibition by the agent relative to a control.  
         [0053]     The test agents were diluted in DMSO or water and tested at several different concentrations. The test agents were added to the agar solution after sterilization, but prior to solidification. Sterile paper disks were soaked in a suspension of  Aspergillus niger  ATCC 9642 and  Aspergillus flavus  ATCC 9643 and placed on the agar plates. The plates were incubated for 48 hours at 25° C. The zones of fungal growth (or no growth) were analyzed and the minimum total inhibitory concentration (%) was estimated for each agent. Table 3 presents the minimum inhibitory concentration of each agent, in ranked order.  
                                                           TABLE 1                           Biocide Performance in ASTM D 2020 Fungal Resistancy Test                Observed Fungal Growth after 14   Fungus               Days incubation at 28° C.   Non-   Fungus            Sample   1   2   3   Resistant   Resistant               Control Diluent DMSO   Growth   Growth   Growth   X           Metasol-TK 100 200 ppm   No Growth   No Growth   No Growth       X       Metasol-TK 100 400 ppm   No Growth   No Growth   No Growth       X       Metasol-TK 100 600 ppm   No Growth   No Growth   No Growth       X       Tox-Guard*Dry 200 ppm   Growth   Growth   Growth   X       Tox-Guard*Dry 400 ppm   Growth   Growth   Growth   X       Tox-Guard*Dry 600 ppm   Growth   Growth   Growth   X       Santoquin 200 ppm   Growth   Growth   Growth   X       Santoquin 400 ppm   No Growth   No Growth   No Growth       X       Santoquin 600 ppm   No Growth   No Growth   No Growth       X       BIOX-AUSD 200 ppm   Growth   Growth   Growth   X       BIOX-AUSD 400 ppm   Growth   Growth   Growth   X       BIOX-AUSD 600 ppm   Growth   Growth   Growth   X       Mintrex Cu 200 ppm   Growth   Growth   Growth   X       Mintrex Cu 400 ppm   Growth   Growth   Growth   X       Mintrex Cu 600 ppm   Growth   Growth   Growth   X                  
 
         [0054]    
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                   
               
               
                 Santoquin Performance in ASTM D 2020 Fungal Resistancy Test 
               
             
          
           
               
                   
                 Observed Fungal 
                 Fungus 
                   
               
               
                   
                 Growth after 14 
                 Non- 
                 Fungus 
               
               
                 Sample 
                 Days incubation at 28° C. 
                 Resistant 
                 Resistant 
               
               
                   
               
               
                 Santoquin 0.1%-1 
                 No growth 
                   
                 X 
               
               
                 Santoquin 0.1%-2 
                 No growth 
                   
                 X 
               
               
                 Santoquin 0.1%-3 
                 No growth 
                   
                 X 
               
               
                 Santoquin 1.0%-1 
                 No growth 
                   
                 X 
               
               
                 Santoquin 1.0%-2 
                 No growth 
                   
                 X 
               
               
                 Santoquin 1.0%-3 
                 No growth 
                   
                 X 
               
               
                 Kathon 893 0.1%-1 
                 Growth 
                 X 
               
               
                 Kathon 893 0.1%-2 
                 Growth 
                 X 
               
               
                 Kathon 893 0.1%-3 
                 Growth 
                 X 
               
               
                 Kathon 893 1.0%-1 
                 Growth 
                 X 
               
               
                 Kathon 893 1.0%-2 
                 Growth 
                 X 
               
               
                 Kathon 893 1.0%-3 
                 Growth 
                 X 
               
               
                 DMSO-1 
                 Growth 
                 X 
               
               
                 DMSO-2 
                 Growth 
                 X 
               
               
                 DMSO-3 
                 Growth 
                 X 
               
               
                   
               
             
          
         
       
     
         [0055]    
       
         
               
             
               
               
             
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                   
               
               
                 Anti-Fungal Activity of Test Agents 
               
             
          
           
               
                   
                 Minimum Total Inhibitory 
               
               
                 Test Agent 
                 Concentration (%) 
               
               
                   
               
             
          
           
               
                 Cinnamaldehyde 
                 &lt;0.005 
               
               
                 Dehydroacetic Acid 
                 0.01 
               
               
                 Propyl Paraben 
                 0.015 
               
               
                 EDTA 
                 0.02 
               
               
                 BHA (Butylated HydroxyAnisole) 
                 0.025 
               
               
                 Copper Sulfate 
                 0.05 
               
               
                 Eugenol 
                 0.05 
               
               
                 Alpha Lipoic Acid 
                 0.1 
               
               
                 Benzoic Acid 
                 0.1 
               
               
                 Beta-Propiolactone 
                 0.1 
               
               
                 Carvone 
                 0.1 
               
               
                 Citral 
                 0.1 
               
               
                 Diacetyl 
                 0.1 
               
               
                 Hydrogen Peroxide 
                 0.1 
               
               
                 Piperonal 
                 0.1 
               
               
                 Sodium Metabisulfite 
                 0.1 
               
               
                 Sulfuric Acid 
                 0.1 
               
               
                 TBHQ (Tert-ButylHydroQuinone) 
                 0.1 
               
               
                 Valeric Acid 
                 0.1 
               
               
                 Vanillin 
                 0.1 
               
               
                 Acetic Acid 
                 0.2 
               
               
                 Activate DA 
                 0.2 
               
               
                 Alimet (HMTBA)/Propionic Acid (1:3) 
                 0.2 
               
               
                 Butyric Acid 
                 0.2 
               
               
                 Hexadecylpyridinium Cl 
                 0.2 
               
               
                 Proprionic Acid 
                 0.2 
               
               
                 Sodium Bisulfite 
                 0.2 
               
               
                 Xtract 
                 0.2 
               
               
                 65% Prop/20% Lys/15% NH 4 OH 
                 0.5 
               
               
                 65% Prop/35% NH 4 OH 
                 0.5 
               
               
                 Benzaldehyde 
                 0.5 
               
               
                 Boric Acid 
                 0.5 
               
               
                 Copper Mintrex (Cu(HMTBA) 2 ) 
                 0.5 
               
               
                 EQ (Ethoxyquin) Emulsion 
                 0.5 
               
               
                 HCl 
                 0.5 
               
               
                 Maleic Acid 
                 0.5 
               
               
                 Methyl Paraben 
                 0.5 
               
               
                 Phosphoric Acid 
                 0.5 
               
               
                 Sodium Diacetate 
                 0.5 
               
               
                 Acetaldehyde 
                 &gt;0.2 
               
               
                 Culbac Liquid 
                 &gt;0.2 
               
               
                 3-Hydroxy-2-Butanone 
                 &gt;0.5 
               
               
                 3-Hydroxypropionic Acid 
                 &gt;0.5 
               
               
                 Adipic Acid 
                 &gt;0.5 
               
               
                 Alpha Tocopherol 
                 &gt;0.5 
               
               
                 Alpha Tocopherol Acetate 
                 &gt;0.5 
               
               
                 Ascorbic Acid 
                 &gt;0.5 
               
               
                 Ascorbyl Palmitate 
                 &gt;0.5 
               
               
                 BHT (Butylated HydroxyToluene) 
                 &gt;0.5 
               
               
                 Calcium Acetate 
                 &gt;0.5 
               
               
                 Calcium Propionate 
                 &gt;0.5 
               
               
                 Citric Acid 
                 &gt;0.5 
               
               
                 Cysteine 
                 &gt;0.5 
               
               
                 Decanal 
                 &gt;0.5 
               
               
                 Delta Tocopherol 
                 &gt;0.5 
               
               
                 Dilauryl Thiodipropionate 
                 &gt;0.5 
               
               
                 Dodecyl Gallate 
                 &gt;0.5 
               
               
                 Ethanol 
                 &gt;0.5 
               
               
                 Ethoxyquin 
                 &gt;0.5 
               
               
                 Fumaric Acid 
                 &gt;0.5 
               
               
                 Gallic Acid 
                 &gt;0.5 
               
               
                 Gluconic Acid 
                 &gt;0.5 
               
               
                 Glycine 
                 &gt;0.5 
               
               
                 Glycolic Acid 
                 &gt;0.5 
               
               
                 HMTBA (2-Hydroxy- 
                 &gt;0.5 
               
               
                 4(NMethylThio)Butanoic Acid) 
               
               
                 Lactic Acid 
                 &gt;0.5 
               
               
                 Lecithin 
                 &gt;0.5 
               
               
                 Limonene 
                 &gt;0.5 
               
               
                 Lysine 
                 &gt;0.5 
               
               
                 Malonic Acid 
                 &gt;0.5 
               
               
                 Methionine 
                 &gt;0.5 
               
               
                 MHA (Methionine Hydroxy Analog) 
                 &gt;0.5 
               
               
                 Octyl Gallate 
                 &gt;0.5 
               
               
                 Potassium Acetate 
                 &gt;0.5 
               
               
                 Potassium Benzoate 
                 &gt;0.5 
               
               
                 Potassium Sorbate 
                 &gt;0.5 
               
               
                 Propyl Gallate 
                 &gt;0.5 
               
               
                 Sodium Acetate 
                 &gt;0.5 
               
               
                 Sodium Benzoate 
                 &gt;0.5 
               
               
                 Sodium bi-Phosphate 
                 &gt;0.5 
               
               
                 Sodium Citrate 
                 &gt;0.5 
               
               
                 Sodium Gluconate 
                 &gt;0.5 
               
               
                 Sodium Hexametaphosphate 
                 &gt;0.5 
               
               
                 Sodium Lactate 
                 &gt;0.5 
               
               
                 Sodium Proprionate 
                 &gt;0.5 
               
               
                 Sodium Pyrophosphate 
                 &gt;0.5 
               
               
                 Sodium Sulfite 
                 &gt;0.5 
               
               
                 Sodium Thiosulfate 
                 &gt;0.5 
               
               
                 Stearyl Citrate 
                 &gt;0.5 
               
               
                 Tartaric Acid 
                 &gt;0.5 
               
               
                 ToxGuard Liquid (New sample) 
                 &gt;0.5 
               
               
                 Tryptophan 
                 &gt;0.5 
               
               
                 DMSO 
                 &gt;1 
               
               
                 ToxGuard Liquid (Old sample) 
                 &gt;2 
               
               
                 ToxGuard Dry (Old sample) 
                 &gt;3 
               
               
                 ToxGuard Dry (New sample) 
                 &gt;5