USOO6472214B2 (12) United States Patent (10) Patent No.: US 6,472,214 B2 Pate (45) Date of Patent: Oct. 29, 2002 (54) FREEZE MONITORING DEVICE 4,892.677 A * 1/1990 Preziosi et al. .......... 252/408.1 (75) Inventor: Gordhanbhai N. Patel, Middlesex, NJ * cited by examiner (US) Primary Examiner-Lyle A. Alexander (74) Attorney, Agent, or Firm Joseph T. Guy; Nexsen (73) Assignee: JP Labs, Inc., Middlesex, NJ (US) Pruet Jacobs & Pollard, LLC (*) Notice: Subject to any disclaimer, the term of this (57) ABSTRACT patent is extended or adjusted under 35 - 0 U.S.C. 154(b) by 0 days. A device composed of (1) a color changing indicator, (2) an optional polymeric binder, preferably having gel forming capability, and (3) an activator Solvent System which induces (21) Appl. No.: 09/897,240 a color change in the indicator when device is frozen, in the (22) Filed: Jul. 2, 2001 region of about 0 to -30°C. An example of the device is an O O indicator of a fine dispersion of partially polymerized (65) Prior Publication Data diacetylene of the formula: R-C=C-C=C-R, where R US 2001/0046451 A1 Nov. 29, 2001 is a Substituent group, e.g., 4BCMU where R-(CH.) OCONHCHCOO(CH), H, dispersed in a mixture of Related U.S. Application Data Solvents, e.g., 96:4 water:ED (ethylene glycol diacetate), with or without a polymeric binder. When the temperature of (63) Continuation-in-part of application No. 09/320,358, filed on the device is lowered to the freezing point of water, the May 26, 1999, now abandoned. activator Solvent phase Separates out of the mixture and (51) Int. Cl. ................................................ G01N 33/02 induces a color change in the indicator. The device can (52) U.S. Cl. ................................. 436/2:436/7, 436/20; undergo an irreversible color change, e.g., from blue to red, 436/164; 436/166; 422/58; 422/61; 426/88 when the activator mixture is frozen in the region of about (58) Field of Search s 422/56-58; 436/2.7 0 to 30° C. The device made from the above system can be - - - - - - - - - -4.36.20, 164 166: 426/87 ss used as a freeze indicator for monitoring the undesirable s s s freezing of materials, Such as emulsions, lateX paints, pro (56) References Cited duce foods, flowers, Sea foods, and vaccines which require freeze monitoring. U.S. PATENT DOCUMENTS 3,194.669 A * 7/1965 Koch 57 Claims, 3 Drawing Sheets 50 15 l 40 45 3226,53225252X226.52265 56 is ris INIa fast Z s 1-20 2 ZZZZZZZZZZZZZZZZZZZZG 77.27 Otto FOODOT titledODI sent IN XXXXXXXXXXXXywyrry rXXXXXXXXXXXXXXXXXXXX SaaSasasasa7 NYNYX YX 7 N7N 2-2 2S2s2S2S 30 75-S U.S. Patent Oct. 29, 2002 Sheet 1 of 3 US 6,472,214 B2 50 15 l 40 3%22%22S2X22.9% Nijin, 56 IWAE. M44/ a 24-444444444444444" . O SAS A SA S XE 1 EE 2ZZZZZZZZZZZZZZZZZ777233% 32&E s T WAY N s XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.IN SSSSSSSSSSSSS S1 siassissisi is it is T.I DDD is a . 60 EE 4411,442 EXE2EAO SASO O Ao s.A25EO S XEE Ed 4 A Ö ( A 302d2. One Y. U.S. Patent Oct. 29, 2002 Sheet 2 of 3 US 6,472,214 B2 50 15 l 2.5226X226252.2255225 45 NNN 55 / 60 ILEarlyEEEEEEEEEEEEEEEEEEEEEEEEEEE 22,727 yr E X S AXS A SA 35 Eato O?o o,cy ao 322dD S X.2, 25 Ot V Ole OECD al Effff:ffff:ffff:ffff:salass as 65 w NN KX IMEzzzzzzzzzzzzzzzzzzy to OdoSAXS o Ao O S.A29S XE 7 A92ILLION is a 52892 ErffOla W NYNYNNNNNNNYNYNYNNY: NYUNYNYSNSN U.S. Patent Oct. 29, 2002 Sheet 3 of 3 US 6,472,214 B2 60 E. x sax sat SAEE if x C.C 113-452226/3262.522662x26 5 5 NN Ry SY A. R Saya ys ars earl s se N S. l O 115- x 40 70 75 S US 6,472,214 B2 1 2 FREEZE MONITORING DEVICE diacetylene, it can extract monomer and cause a color change in the diacetylene. Thus, one is aware that the PRIORITY APPLICATIONS perishable product, e.g., live virus polio Vaccine, has been undesirably Subjected to a freezing temperature and is This application is a continuation-in-part of U.S. patent possibly damaged. application Ser. No. 09/320,358 filed May 26, 1999 now By this invention there is provided a device comprising: abandoned. an indicator which is capable of undergoing a color change; BACKGROUND OF THE INVENTION and an activator System. The activator System is comprised of a Solution of water and an activator Solvent. The activator 1. Field of the Invention Solvent is miscible with water and capable of Separating out This invention relates to a device for monitoring the of the solution at or below the freezing point of water freezing temperature history of a perishable product for thereby inducing a color change in the indicator upon example, vaccines, fresh produce, flowers, lateX paints, contact. The indicator is in contact with the activator System emulsions Such as milk, fruit juices, and yogurt, to determine and when the device is Subjected to a temperature at or if the product has been Subjected to a freezing temperature 15 below the freezing point of water, Sufficient Solvent Sepa and thus has been damaged. rates from the Solution to contact the indicator and induce a 2. Brief Description of Prior Art color change in the indicator. There are a variety of defrost indicators reported in the Further provided is a proceSS for monitoring the freezing literature for monitoring of thawing of perishables Such as temperature history of an article comprising the Step of ice-cream. See U.S. Pat. Nos. 4,892,677, 5,685,641, 5,695, affixing a device, as described above, to the article and 284 and 4,735,745, which utilize a diacetylene as an indi comparing any change in color to a control color. cator. This type of indicator undergoes a color change when Furthermore there is provided a color indicator compris the product temperature undesirably exceeded about 0° C. ing a gel formulation comprised of water, a water miscible U.S. Pat. No. 4,892,677, to Preziosi, et al., describes a 25 Solvent capable of phase Separation from the water Solution defrost indicator which is prepared by mixing a diacetylene in the temperature range of 0 to -30°C., a gelling agent and monomer with a solvent. The mixture is frozen and irradi a dispersion of a partially polymerized diacetylene. ated in the frozen State to partially polymerize the diacety These and other advantages, as will be realized, are lene. Once the frozen indicator is exposed to a temperature provided in a proceSS for detecting temperature excursions Sufficient to melt the solvent the monomer is extracted from of an article below a threshold temperature. The process the partially polymerized diacetylene thereby forming a comprises the Steps of: polymer enriched diacetylene phase and a monomer a) preparing a freeze indicator comprising an activator enriched solvent phase. The device of Preziosi et al. is System and an indicator. irreversible and unidirectional and only capable of providing b) partially polymerizing said indicator at a temperature a signal with an increase in temperature. 35 above the threshold temperature; U.S. Pat. Nos. 4,191,125, 5,111,768, and 5,239,942 c) attaching the freeze indicator to the article wherein describe freeze indicators. These indicators usually employ when the article is exposed to a temperature below the a frangible glass container which contains a colored aqueous threshold temperature the activator Solvent Separates Solution which ruptures upon freezing and then contacts a from the water and reacts with the indicator to cause a wick Such as paper upon thawing to indicate that undesirable 40 color change in the indicator. The activator System thawing has occurred. Other representative patents on comprises water and an activator Solvent which is freeze-thaw type indicators include U.S. Pat. Nos. 4,114, miscible in the water above the threshold temperature 443, 4,145,918 4,148,748, 4,191,125, 5,111,768 and 5,239, and separates from the water below said threshold 942. These type of devices are large, complex, difficult to temperature. The indicator is capable of irreversibly manufacture, and expensive. 45 reacting with Said Solvent when Separated from Said There is a constant need in the art for a device which is Water. Simple, easy to make, does not depend upon the use of a Another embodiment is provided in a method for prepar frangible glass container, and is economical for commercial ing an indicator for indicating an excursion below a thresh production. Especially there is a need for a device to monitor old temperature comprising: mixing an indicator with a the freeze temperature of Such perishable food products as 50 Solvent System wherein the Solvent System comprises a host described above, which become damaged and inedible if Solvent and an activator Solvent and wherein the activator frozen. Solvent is miscible in the host solvent above the threshold temperature and Separates from the host Solvent below the SUMMARY OF THE INVENTION threshold temperature, exposing the indicator to radiation to 55 polymerize the indicator wherein the exposing is done at a It is an object of the present invention to provide a device temperature above the threshold temperature, wherein when which can indicate temperature excursions below a thresh the indicator is exposed to a temperature below the threshold old temperature. temperature the activator Solvent Separates from the host It is another object of the present invention to provide a Solvent and reacts with the indicator and the indicator device which irreversibly indicates a temperature excursion 60 changes color.