Abstract:
A thermal cutoff member and compositions used to manufacture such members are described herein as including at least two organic compounds which, when sufficiently combined, give rise to a component which has a lower melt transition temperature than the initial organic compounds prior to combining the same. The thermal cutoff member is generally utilized in a thermal cutoff construction having an electrical switching unit that changes its operating condition when the member therein melts by being heated to a certain temperature for the particular material that forms the member being utilized.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to compositions useful for cutoff devices and, more particularly, the thermal cutoff compositions employing a mixture of at least two crystalline organic compounds. 
     2. Background of the Invention 
     It is known to provide thermal cutoff assemblies having electrical switching units which change its operating condition when a member disposed therein melts by being heated to a certain temperature. The members typically include what will hereinafter be referred to as a thermal cutoff composition. 
     Heretofore, thermal cutoff compositions have been formulated from a single organic compound having a known melting temperature commonly in pellet form. These compounds were typically blended with a binder, such as an epoxy, a lubricant such as calcium stearate and/or a pigment such as a metal oxide for purposes of color coding the pellet. For example, U.S. Pat. No. 4,514,718 discloses 4-methylumbelliferone as a preferred organic compound for thermal cutoff applications. While the foregoing thermal cutoff composition has proven useful, significant improvements and advantages are provided by the present invention. 
     As will be understood by those skilled in the art, the melt temperature is not the only characteristic of thermal cutoff compositions which is important. In addition, the composition should be chemically stable, thermally stable and typically electrically non-conductive in the molten state. 
     SUMMARY OF THE INVENTION 
     It is a feature of this invention to provide thermal cutoff compositions useful in association with thermal cutoff constructions wherein the composition is capable of being formed into a member adapted to melt (or otherwise changes shape) at a certain temperature or other condition and thereby cause an electrical switching unit of the thermal cutoff construction to change its operating condition. 
     In particular, it has been found that blends employing at least two organic compounds having known melt temperatures, when brought together via blending or otherwise combined, exhibit improved thermal properties and performance characteristics over the individual organic components. In addition to having the desired melt temperatures, the compositions of the present invention exhibit good chemical and thermal stability. Further, the thermal cutoff compositions are electrically non-conductive in the molten state. 
     For purposes of the present invention, it is important to note that the phrase “melting point temperature” as used herein, does not refer to a temperature wherein the product is at the equilibrium point between liquid and solid phases. Rather, melting point temperature is to be considered the temperature at which the thermal cutoff composition (pellet) no longer possesses the structural integrity required to maintain a switch in a held open or held closed position depending on the embodiment. To the extent that such melt temperatures require measurement, various apparatuses such as those produced by Thomas Hoover, Mettler and Fisher-Johns may be employed. Differential Scanning Colorimetry (DSC) techniques are also useful. 
     Accordingly, it is a primary object of this invention to provide thermal cutoff compositions for forming members employed in thermal cutoff constructions. 
     It is a further object of the present invention to provide thermal cutoff compositions with defined melt temperature ranges. 
    
    
     Other objects, uses and advantages of this invention should be apparent from a reading of the detailed description, particularly when taken in conjunction with the accompanying drawings wherein: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an enlarged cross sectional view of a thermal cutoff construction utilizing the member of this invention; 
     FIG. 2 is a view similar to FIG.  1  and illustrates the thermal cutoff construction after the actuating member thereof has melted to cause the electrical switching unit thereof to change its operating condition; 
     FIG. 3 is a side perspective view illustrating the improved actuating member of this invention; 
     FIG. 4 is a side view of a sliding contact member of the switch construction of FIG. 1; 
     FIG. 5 is a side view of one of the springs of the switch construction of FIG. 1; 
     FIG. 6 is a cross sectional view of the ceramic end plug of the switch construction of FIG. 1; 
     FIG. 7 is an elevation view of the thermal cutoff construction of FIG. 1, but in reduced size illustrating approximately the actual size of the thermal cutoff construction. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While several features of this invention are described and illustrated in this specification, and this invention can be adapted to provide thermal cutoff compositions to be used in thermal cutoff constructions, it is to be understood that the various disclosed features of this invention are not exhaustive; further, such features can be utilized singly or in any combination thereof to provide such a member of different configurations and/or for other types of thermal cutoff constructions as desired. 
     Therefore, this invention is not to be limited to only the embodiment illustrated in the drawings because the drawings are merely utilized to illustrate one of the wide variety of uses of the thermal cutoff compositions. For example and without limitation, the thermal cutoff compositions of the present invention would generally be useful in association with the entire MICROTEMP® line of thermal cutoff assemblies commercially available by Therm-O-Disc, Inc. of Mansfield, Ohio. 
     Referring now to FIGS. 1,  2  and  7 , the thermal cutoff construction that utilizes the improved features of this invention is generally indicated by the reference numeral  10  and is substantially identical to the thermal limiter construction disclosed in U.S. Pat. No. 4,075,595 to Plasko; U.S. Pat. No. 3,180,958 to Merrill; U.S. Pat. No. 3,519,972 to Merrill, and, in particular, U.S. Pat. No. 4,514,718 to Birx, whereby these four U.S. patents are incorporated into this disclosure by this reference thereto for any information desired as to the details of the particular parts and operation of the thermal cutoff construction  10 . As such, the thermal cutoff construction  10  will merely be described in a general manner. 
     In general, the thermal cutoff construction  10  includes a conductive metallic casing  11  having a metallic electrical conductor  12  secured in electrical contact with a closed end  13  of the casing  11 . A ceramic end plug  14 , as best illustrated in FIG. 6, is disposed in an open end  15  of the casing  11  and is secured thereto by a turned over portion  16  of the end  15  of the casing  11  as illustrated in FIG. 1 while being sealed thereto by an epoxy seal  28 , a second metallic electrical conductor  17  passing through the bushing  14  and having an enlarged head  18  disposed against one end  19  of the end plug  14  and another end  20  projecting out of the outer end  21  of the end plug  14  and seal  28  for external lead attachment purposes. 
     A sliding conductive contact member  22  of metallic material, as best illustrated in FIG. 4, is disposed inside the casing  11  and has resilient peripheral fingers  23  disposed in sliding engagement with the internal peripheral surface  24  of the casing  11  to provide electrical contact therebetween. 
     A thermally responsive pellet-like member  25 , as best illustrated in FIG. 3, is formed of material in a manner hereinafter set forth and is disposed in the casing  11  against the end wall  13  thereof. 
     A pair of compression springs  26  and  27  are respectively disposed on opposite sides of the sliding contact member  22  such that the compression spring  26  is in a compressed condition between the solid member  25  and the contact member  22  and has a stronger compressed force than the force of the compressed spring  27  which is disposed between the contact member  22  and the end plug  14  whereby the contact member  22  is held by the force of the spring  26  in electrical contact with the enlarged end  18  of the conductor  17  so that an electrical circuit is provided between the conductors  12  and  17  through the casing  11  and sliding contact member  22  of the thermal cutoff construction  10  as illustrated in FIG.  1 . 
     However, when the particular temperature for melting the pellet-like member  25  is reached, such as during an adverse heating condition adjacent the thermal cutoff construction  10 , the member  25  melts in the manner illustrated in FIG. 2 whereby the springs  26  and  27  are adapted to expand, as illustrated by spring  27  in FIG. 5, and thereby through the relationship of the particular forces and length of the springs  26  and  27 , the sliding contact member  22  is moved out of electrical contact with the end  18  of the second conductor  17  in the manner illustrated in FIG. 2 so that the electrical circuit between the conductors  12  and  17  through the thermal cutoff construction  10  is broken and remains open as illustrated in FIG.  2 . 
     The improved thermal cutoff compositions of the present invention comprise at least two distinct thermally and chemically stable organic compounds which, when combined, exhibit improved properties, such as a melting point temperature lower than either of the starting compounds while remaining electrically non-conductive in the molten state. By “electrically non-conductive”, it is preferably meant that the composition is capable of withstanding a 240 volt, 60 Hz sinusoidal potential between two electrodes at least 5° C. above the melt transition temperature, for one minute without conducting greater than 250 mA. More preferably, the composition should be capable of withstanding a 240 volt, 60 Hz sinusoidal potential at least 10° C. above the melt transition temperature for at least about one minute without conducting greater than 250 mA. Under highly preferred embodiments, the thermal cutoff compositions of the present invention should be capable of withstanding a 240 volt, 60 Hz sinusoidal potential at least 60° C. above the melt transition temperature for at least about one minute without conducting greater than 250 mA. 
     While the thermal cutoff compositions of the present invention should meet or exceed the aforementioned test protocol, it should be understood by those skilled in the art that the compositions are contemplated as being useful for both low voltage and high voltage applications. Further, the compositions of the present invention are expected to meet or exceed UL1020 or EN 60 691 standards. 
     Preferably, the resulting thermal cutoff composition will have a melting point temperature of between about 60° C. to 300° C. and, more preferably, between about 65° C. to about 265° C. Under a highly preferred embodiment the resulting composition will be non-deliquescent, i.e., moisture repellant. As noted above, once intimately combined, the resulting component has a lower melting point temperature than any of the individual organic compounds employed. The differential in melting point temperatures of the organic compounds (pre-blend) versus the thermal cutoff composition (post-blend) gives rise to a composition having a depressed melting point of at least 5° C. That is, the resulting thermal cutoff composition will have a melting point temperature as the term is used herein of at least 5° C. lower than any of the individual organic compounds employed. The depressed melting point of at least 5° C. should result regardless whether the compounds are blended, co-precipitated, co-crystallized or otherwise intimately combined. 
     By way of non-limiting example, the organic compounds set forth in Table I below are considered useful in formulating the thermal cutoff compositions of the present invention. Each of the below listed organic compounds are crystalline in nature and have melting point temperatures of between about 60° C. to about 300° C. 
     
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE I 
               
               
                   
               
               
                   
                   
                   
                 Molecular 
               
               
                   
                 CAS 
                 Melt Point 
                 Weight 
               
               
                 Name 
                 Registry No. 
                 Range*(° C.) 
                 (g/mole) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 2H-1-benzopyran-2-one 
                 91-64-5 
                 68-70 
                 146 
               
               
                 n-butyl-4-hydroxybenzoate 
                 94-26-8 
                 68-69 
                 194 
               
               
                 phenylbenzoate 
                 93-99-2 
                 69-72 
                 198 
               
               
                 diphenyl phthalate 
                 84-62-8 
                 74-76 
                 318 
               
               
                 4-hydroxy-3- 
                 121-33-5 
                 81-83 
                 152 
               
               
                 methoxybenzaldehyde 
               
               
                 1,3-diphenylbenzene 
                 92-06-8 
                 84-88 
                 230 
               
               
                 1,4-dibromobenzene 
                 106-37-6 
                 87-89 
                 235 
               
               
                 triphenylmethane 
                 519-73-3 
                 92-94 
                 244 
               
               
                 4,4′methylene bis 
                 101-77-9 
                 89-91 
                 198 
               
               
                 (benzeneamine) 
               
               
                 diphenylethanedione 
                 134-81-6 
                 94-95 
                 210 
               
               
                 pentanedioic acid 
                 110-94-1 
                 95-98 
                 132 
               
               
                 n-propyl-4-hydroxybenzoate 
                 94-13-3 
                 95-98 
                 180 
               
               
                 xanthene 
                 92-83-1 
                 101-102 
                 188 
               
               
                 3,5-dimethylpyrazole 
                 67-51-6 
                 107-109 
                 96 
               
               
                 1,3-benzenediol 
                 108-46-3 
                 110-113 
                 110 
               
               
                 N-phenyl-2-napthylamine 
                 135-88-6 
                 107-109 
                 219 
               
               
                 N-phenylacetamide 
                 103-84-4 
                 113-115 
                 135 
               
               
                 9H-fluorene 
                 86-73-7 
                 114-116 
                 166 
               
               
                 m-phenylenedibenzoate 
                 94-01-9 
                 117 
                 318 
               
               
                 dihydro-2,5-furandione 
                 108-30-5 
                 119-120 
                 100 
               
               
                 2,,5-pyrrolidinedione 
                 123-56-8 
                 123-125 
                 99 
               
               
                 3-pyridinecarboxamide 
                 98-92-0 
                 130-132 
                 122 
               
               
                 phthalic anhydride 
                 85-44-9 
                 131-134 
                 148 
               
               
                 p-toluenesulfonamide 
                 70-55-3 
                 138-139 
                 171 
               
               
                 dimethyl terephthalate 
                 120-61-6 
                 140-142 
                 194 
               
               
                 N-(4-methylphenyl)acetamide 
                 103-89-9 
                 149-151 
                 149 
               
               
                 hexanedioic acid 
                 124-04-9 
                 152-154 
                 146 
               
               
                 N-phenylbenzamide 
                 93-98-1 
                 164-166 
                 197 
               
               
                 4,4′-dibromobiphenyl 
                 92-86-4 
                 167-170 
                 312 
               
               
                 mannitol 
                 69-65-8 
                 167-170 
                 182 
               
               
                 4-(1,1-dimethylethyl)benzoic 
                 98-73-7 
                 165-167 
                 178 
               
               
                 acid 
               
               
                 N-(2,6-dimethylphenyl) 
                 2198-53-0 
                 182-184 
                 163 
               
               
                 acetamide 
               
               
                 2,4-dinitrobenzeneamine 
                 606-22-4 
                 137-139 
                 183 
               
               
                 7-hydroxy-4-methylcoumarin 
                 90-33-5 
                 190-190 
                 176 
               
               
                 5,5-diethyl-2,4,6(1H,3H,5H)- 
                 57-44-3 
                 189-191 
                 184 
               
               
                 pyrimidinetrione 
               
               
                 1,4-diphenylbenzene 
                 92-94-4 
                 212-213 
                 230 
               
               
                 inositol 
                 87-89-8 
                 224-225 
                 180 
               
               
                 6-phenyl-1,3,5-triazine-2,4- 
                 91-76-9 
                 226-228 
                 187 
               
               
                 diamine 
               
               
                 2-phenylbenzimidazole 
                 716-79-0 
                 293-296 
                 194 
               
               
                 3,7-dihydro-1,3,7-trimethyl-1 
                 58-08-2 
                 232-236 
                 194 
               
               
                 H-purine-2,6-dione 
               
               
                 1,1′-bi-2-naphthol 
                 602-09-5 
                 214-217 
                 286 
               
               
                 4-hydroxy-3-methoxybenzoic 
                 121-34-6 
                 209-213 
                 168 
               
               
                 acid 
               
               
                 2,3-dimethylanthraquinone 
                 6531-35-7 
                 210-212 
                 236 
               
               
                 2-phenylindole 
                 948-65-2 
                 188-190 
                 193 
               
               
                 2-methylphenylacetic acid 
                 644-36-0 
                 88-90 
                 150 
               
               
                 1,3,5-trimethyl-2,4,6tris(3,5-di- 
                 1709-70-2 
                 248-250 
                 774 
               
               
                 tertbutyl-4-hydroxybenzyl) 
               
               
                 benzene 
               
               
                 hydantoin 
                 461-72-3 
                 221-223 
                 100 
               
               
                 7-hydroxycoumarin 
                 93-35-6 
                 230 
                 162 
               
               
                 Carbanilide 
                 102-07-8 
                 239-241 
                 212 
               
               
                 1,5-dichloroanthraquinone 
                 82-46-2 
                 245-247 
                 277 
               
               
                 1,1,1-tris(4-hydroxyphenyl) 
                 27955-94-8 
                 246-248 
                 306 
               
               
                 ethane 
               
               
                 1-Aminoanthraquinone 
                 82-45-1 
                 253-255 
                 223 
               
               
                 2,3,5,6-tetrabromo-p-xylene 
                 23488-38-2 
                 254-256 
                 422 
               
               
                 1,5-dihydroxynapthalene 
                 83-56-7 
                 259-261 
                 160 
               
               
                 2-quinoxalinol 
                 1198-57-2 
                 271-272 
                 146 
               
               
                 2,4-diamino-6-methyl-1,3,5- 
                 542-02-9 
                 274-276 
                 125 
               
               
                 triazine 
               
               
                 7-chloro-4-hydroxyquinoline 
                 86-99-7 
                 276-279 
                 180 
               
               
                 Alizarin 
                 72-48-0 
                 279-284 
                 240 
               
               
                 Anthraquinone 
                 84-65-1 
                 284-286 
                 208 
               
               
                 2,4-diamino-6- 
                 56-06-4 
                 285-286 
                 126 
               
               
                 hydroxypyrimidine 
               
               
                 2-phenylbenzimidazole 
                 716-79-0 
                 296-296 
                 194 
               
               
                 2-amino-4-hydroxy-6- 
                 3977-29-5 
                 &gt;300 
                 125 
               
               
                 methylpyrimidine 
               
               
                 4-amino-2,6- 
                 873-83-6 
                 &gt;300 
                 127 
               
               
                 dihydroxypyrimidine 
               
               
                 2-amino-4,6- 
                 56-09-7 
                 &gt;300 
                 127 
               
               
                 dihydroxypyrimidine 
               
               
                 Uracil 
                 66-22-8 
                 &gt;300 
                 112 
               
               
                   
               
             
          
         
       
     
     In addition to the above described at least two organic compounds, the thermal cutoff compositions of the present invention may optionally include a binder component. The binder, which generally softens (melts) at a temperature below the melting point of the crystalline component, is primarily utilized to assist in the production of pellets. While various binders known for pellet formation can be utilized, preferred binders include polyethylene glycol, 1,3-benzenediol, epoxies, polyamides and mixtures thereof. The binder is generally present in amounts up to about 10.0 wt. % based on the total composition. 
     Additionally, it may be desirable to employ a lubricant to enforce the flow and fill properties when processing pellets. For example, among the numerous lubricants which have proven useful are calcium stearate, boron nitride, magnesium silicate and polytetrafluoroethylene (teflon), among others. The lubricant is generally present in amounts of up to about 5.0 wt. % based on the total composition. 
     It may also be desirable under certain applications to incorporate coloring agents such as pigments into the thermal cutoff composition to allow for rapid visual inspection of the pellets condition. Virtually any known pigment which is compatible with the aforementioned thermal cutoff composition components may be employed. Pigments, when employed, are typically present in amounts of up to about 2.0 wt. %. 
     To analyze the effectiveness of the thermal cutoff compositions of the present invention, various samples as set forth in Table II were prepared and tested to determine the target thermal cutoff temperature range, while exhibiting other desirable characteristics. 
     
       
         
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE II 
               
               
                   
               
             
             
               
                 CAS Reg. 
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 No. 
                 58-08-2 
                 91-78-9 
                 92-94-4 
                 90-33-5 
                 2198-53-0 
                 93-98-1 
                 103-89-9 
                 120-61-6 
                 123-58-8 
               
               
                   
               
               
                 58-08-2 
                 xxx 
               
               
                 91-78-9 
                 177.8(8.9) 
                 xxx 
               
               
                 92-94-4 
                 187.78(−11.7) 
                  201.1(−16.9) 
                 xxx 
               
               
                 90-33-5 
                 145.6(19.6) 
                  169.9(2.9) 
                 181.4(−15.0) 
                 xxx 
               
               
                 2198-53-0 
                 two peaks 
                  169.6(−7.8) 
                 169.1(−14.9) 
                  137.6(11.0) 
                 xxx 
               
               
                   
                 @−164.2 
               
               
                 93-98-1 
                 143.5(1.1) 
                  158.9(−5.8) 
                 156.2(−8.4) 
                  142.5(1.6) 
                 131.4(−2.8) 
                 xxx 
               
               
                 103-89-9 
                 137.0(−2.6) 
                  145.5(3.0) 
                 144.5(−6.7) 
                  126.3 
                 120.0(0.7) 
                 122.4(−1.2) 
                 xxx 
               
               
                   
                   
                   
                   
                 (premelt) 
               
               
                 120-81-6 
                 131.3(−2.6) 
                  136.9(−1.2) 
                 134.5(−2.5) 
                  134.8(−4.5) 
                 131.8(−14.6) 
                 124.9(−4.8) 
                 121.7 (−8.7) 
                 xxx 
               
               
                 123-58-8 
                 111.6(−2.2) 
                  120.1(−0.4) 
                 multi peak 
                  115.6(−1.6) 
                 114.6(−14.7) 
                 114.0(−11.8) 
                 107.4(−10.2) 
                 116.2(−20.4) 
                 xxx 
               
               
                 94-01-9 
                 110.8(0.1) 
                 *116.6(−0.7) 
                 113.7(0.1) 
                 *115.5(−2.3) 
                 112.8(−9.6) 
                 109.5(−3.0) 
                 107.3(−4.2) 
                 101.4(0.5) 
                 108.5(−21.6) 
               
               
                 103-84-4 
                 107.2(2.0) 
                 *113.7(−1.7) 
                 113.3(−4.1) 
                  101.4(7.2) 
                  95.2(0.2) 
                 100.1(0.2) 
                  99.0(−2.6) 
                 102.2(−6.8) 
                  88.2(−10.8) 
               
               
                 67-51-6 
                 102.7(−7.7) 
                 mult. peak 
                 mult. peak 
                 mult. peak 
                  95.6(−11.8) 
                 mult. peak 
                  87.9(−1.3) 
                  97.0(−11.2) 
                  82.9(−18.5) 
               
               
                 92-83-1 
                   
                   
                  98.3(0.5) 
                 *101.3 
                  99.2(−13.1) 
                  97.8(−8.8) 
                  97.3(−9.2) 
                  89.3(−1.8) 
                 mult peak 
               
               
                 134-81-6 
                   
                   
                 *93.1(−0.7) 
                  *94.4 
                  91.6(−9.2) 
                  89.5(−2.45) 
                  89.3(−4.9) 
                  85.5(−1.5) 
                  90.2(−21.7) 
               
               
                 519-73-3 
                   
                   
                 *91.5(−0.9) 
                  *93.6 
                  92.7(−12.6) 
                 *91.6(6.6) 
                 *91.9(−9.5) 
                  85.9(−3.9) 
                 mult. peak 
               
               
                 108-37-6 
                   
                   
                  84.7(0.6) 
                  *87.8 
                 *86.3(−11.2) 
                 mult. peak 
                 *85.7(−8.0) 
                  79.9(−2.4) 
                 mult. peak 
               
               
                 121-33-5 
                   
                   
                 multi. peak 
                  *80.2 
                  74.9(−3.5) 
                  77.1(−1.0) 
                  72.3(1.7) 
                  75.8(−1.9) 
                  64.9(−5) 
               
               
                 84-62-8 
                   
                   
                 *74.0(0.6) 
                   
                 *72.8(−5.7) 
                 *72.6(−1.9) 
                 *72.5(−3.5) 
                  71.1(−1.9) 
                 *72.4(−15) 
               
               
                   
               
               
                 CAS Reg. 
               
               
                 No. 
                 94-01-9 
                 103-84-4 
                 67-51-6 
                 92-83-1 
                 134-81-6 
                 519-73-3 
                 106-37-6 
                 121-35-5 
                 84-62-8 
               
               
                   
               
               
                 58-08-2 
               
               
                 91-78-9 
               
               
                 92-94-4 
               
               
                 90-33-5 
               
               
                 2198-53-0 
               
               
                 93-98-1 
               
               
                 103-89-9 
               
               
                 120-81-6 
               
               
                 123-58-8 
               
               
                 94-01-9 
                 xxx 
               
               
                 103-84-4 
                  95.2(−7.3) 
                 xxx 
               
               
                 67-51-6 
                  92.2(−13.4) 
                  74.6(−5.8) 
                 xxx 
               
               
                 92-83-1 
                  80.9(0.7) 
                  89.8(−16.2) 
                  82.2(−19.4) 
                 xxx 
               
               
                 134-81-6 
                  77.9(1.1) 
                  80.4(−8.8) 
                  77.7(−18.9) 
                  68.5(−1.9) 
                 xxx 
               
               
                 519-73-3 
                  81.1(−4.0) 
                  89.0(−19.5) 
                  80.7(21.9) 
                  65.8(−1.5) 
                  66.1(−2.93) 
                 xxx 
               
               
                 108-37-6 
                  73.3(−.02) 
                  81.3(−16.1) 
                  72.0(−17.4) 
                  60.0(0.4) 
                  62.7(−2.3) 
                  57.2(0) 
                 xxx 
               
               
                 121-33-5 
                  74.1(−3.9) 
                  62.5(0.3) 
                 mult. peak 
                  71.2(−12.8) 
                  64.5(−6.9) 
                  73.9(−18.4) 
                  67.1(−15.0) 
                 xxx 
               
               
                 84-62-8 
                  68.4(−1.8) 
                  87.4(−8.7) 
                  67.1(−14.9) 
                  59.7(−2.8) 
                  57.0(−0.5) 
                  80.0(−5.4) 
                  56.1(−1.4) 
                  58.9(−8.4) 
                 xxx 
               
               
                   
               
               
                 *No change from starting material  
               
               
                 Numbers in ( ) represent Predicted T a -Experimental T a   
               
             
          
         
       
     
     Once it is determined that each of the listed compounds, when mixed with a second compound, give rise to viable thermal cutoff compositions, certain samples may be prepared to verify whether compounds may be formulated with specific cutoff target temperatures. 
     Initially, a first sample can be prepared with the objective of obtaining a product having an expected melting point temperature (melt transition temperature) of about 176° C. The sample can be prepared by mixing between about 38% to about 60% by weight 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione with 62% to about 40% by weight 1,4-diphenylbenzene in a high speed grinding mill mixer. Added to the aforementioned organic compounds may be 1% by weight of a polyamide binder and 1% by weight of an organic azo pigment. The resulting composition is expected to exhibit a melting point temperature of about 188° C. 
     Additional samples can be prepared with the objective of obtaining a product having a melting point temperature of about 162° C. In this regard, a sample can be prepared by mixing a three compound blend including 45% by weight 1,1′-bi-2-naphthol, 19.5% by weight 6-phenyl-1,3,5-triazine-2,4-diamine and 35.5% by weight 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione in a high speed grinding mill mixer. After blended for approximately five minutes, the sample may be analyzed using differential scanning calorimetry (DSC). The resulting composition is expected to exhibit a melting point temperature of about 154° C. 
     A third sample can be prepared with the objective of obtaining a product having a melting point temperature of about 108° C. The samples are prepared by mixing 14-16% by weight 7-hydroxy-4-methylcoumarin with N-phenylacetamide in a high speed grinding mill mixer. After blending for approximately five minutes, the sample may be analyzed using differential scanning calorimetry (DSC). The resulting composition is expected to exhibit a melting point temperatures of about 102° C. 
     A fourth sample can be prepared with the objective of achieving a composition having a melting point temperature of about 74° C. The sample can be prepared by mixing 14-16% by weight of N-(4-methylphenyl) acetamide with 84-86% by weight 4-hydroxy-3-methoxybenzaldehyde in a high speed grinding mill mixer. After blended for approximately five minutes, the sample may be analyzed using differential scanning calorimetry (DSC). The resulting composition is expected to exhibit a melting point temperature of about 72° C. 
     In addition to exhibiting repeatable transition melt temperatures, the compositions of the present invention are also expected to exhibit clean current interrupt properties, decreased composition costs and should allow for designing thermal cutoffs to specific customer needs. Further, the compositions of the present invention can be quantitatively analyzed using known techniques such as proton or carbon nuclear magnetic resonance, mass spectroscopy or Fourier transform infrared spectroscopy techniques, by way of non-limiting example. 
     As demonstrated by the foregoing samples, thermal cutoff compositions of the present invention may be custom formulated to give precise thermal cutoff temperatures, while exhibiting other important characteristics such as chemical and thermal stability. While the thermal cutoff composition may be formed into the shape such as that illustrated in FIG. 3, it should be understood that the material can be formed in other shapes and still provide its actuating function at the target melting temperatures. 
     While it will be apparent that the preferred embodiments of the invention disclosed are well calculated to fulfill the objects stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the spirit thereof.