JPH0462746B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a moist heat detection indicator that is a chemical indicator suitable for detecting sterilization conditions and confirming the sterilization process, for example, in process control of high-pressure steam sterilization in the medical field and retort sterilization in the food field.

[Conventional technology]

One of the methods for sterilizing medical instruments in the medical field is high-pressure steam sterilization, which involves heating with high-pressure steam for a certain period of time. Indicators for detecting sterilization conditions include chemical indicators and biological indicators. As a chemical indicator, for example, those utilizing the discoloration of dark blue due to thermal decomposition reaction under alkaline conditions are disclosed in Japanese Patent Publication No. 18331/1983 and Japanese Patent Publication No. 18331/1973.
−18464 Publication, Japanese Patent Publication No. 59-13550, Japanese Patent Publication No. 18464
It is disclosed in Publication No. 50-150475. Also Tokko Akira
Publication No. 45-4690, Publication No. 51-4124, Special Publication No.
No. 57-31597 and Japanese Patent Application Laid-open No. 61-287972,
Chemical indicator using discoloration due to chemical reaction between metal salts of lead or copper and inorganic sulfur or inorganic sulfur compounds, Japanese Patent Publication No. 52-2324, Japanese Patent Publication No. 52-2325, Japanese Patent Application Laid-open No. 122527/1983 The publication discloses a method that utilizes the discoloration caused by the thermal decomposition reaction of methine dyes or cyanine dyes. In addition to these, Japanese Patent Publication No. 57-9025 discloses an indicator that utilizes the coloring effect caused by the chemical reaction between a metal salt of a long-chain fatty acid and phloroglucin or a derivative thereof. In the medical field, high-pressure steam sterilization at 121°C for 20 minutes is generally performed, and the conditions for the indicator's color change must match the conditions for completing the sterilization process. However, the indicator color change conditions disclosed in the above-mentioned publications may not necessarily match the sterilization completion conditions. For example, conventionally used indicator compositions consisting of basic carbonate, zinc sulfide and chlorinated polypropylene resin varnish do not change color at 121° C. for 20 minutes, which is inconsistent with the completion conditions for sterilization. This indicator
A high temperature of 132 degrees Celsius is required to cause the color to change in 20 minutes, and there is a risk of thermal deterioration of medical equipment at this temperature. It is also difficult to adjust the composition and change the discoloration conditions. Furthermore, some conventional compositions change color not only when heated with wet heat but also when heated with dry heat, which poses a problem when used as an indicator for detecting high-pressure steam sterilization conditions in the medical field. Further, these indicator compositions may be applied to detect conditions of retort sterilization treatment in the food field. However, since this process uses a large amount of high-temperature water and cooling water, there is a risk that the indicator composition may dissolve and flow out. For example, in the case of a conventionally used composition consisting of navy blue, soda carbonate, and rosin-modified maleic acid,
When heated with steam, the color changes from blue to green in about 2 minutes, and changes to yellow in 15 minutes. However, this composition has the problem of non-uniform discoloration in areas that come into direct contact with water. This is thought to be due to the composition dissolving in water and flowing out, and there is currently no indicator that stably functions as an indicator for detecting retort sterilization conditions.

[Problem to be solved by the invention]

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide an indicator for moisture and heat detection that has discoloration conditions consistent with high-pressure steam sterilization processing conditions in the medical field and retort sterilization processing conditions in the food field. shall be.

[Means to solve the problem]

The present inventors have found that by using water-insoluble bismuth compounds and thiourea compounds as coloring components, using a synthetic rubber resin as a binder, and further coating the surface with a synthetic resin, the water resistance of the composition can be improved. We have discovered that the discoloration conditions can be matched to the completion conditions of high-pressure steam sterilization in the medical field and retort sterilization in the food field, and have completed the present invention. That is, in the moist heat detection indicator of the present invention, a composition consisting of a bismuth compound, a thiourea compound, and a synthetic rubber resin that is insoluble or sparingly soluble in water is coated on a sheet base material with a substantially transparent synthetic resin. Covered. The bismuth compounds include bismuth sesquioxide, basic bismuth carbonate, bismuth hydroxide,
One or more compounds selected from basic bismuth nitrate and basic bismuth acetate. The thiourea compound is one or more compounds selected from thiourea, methylthiourea, ethylthiourea, trimethylthiourea, tolylthiourea, diphenylthiourea, ditolylthiourea, phenylthiourea, and methylolthiourea. Synthetic rubber resin is a binder for making ink, and for example, commercially available ink vehicles containing synthetic rubber resin can be used. In the present invention, various additives such as Carplex (trade name, manufactured by Shionogi & Co., Ltd.) and talc may be added in addition to the above-mentioned compounds. The composition used in the present invention is obtained by mixing a synthetic rubber resin, a bismuth compound, and a thiourea compound or a derivative thereof dissolved in a solvent to form an ink. To make ink, use a dispersing machine such as a ball mill, roll mill, or sand mill to form a printing ink such as gravure printing ink, screen printing ink, or flexographic printing ink, and then apply it to a suitable sheet such as paper, synthetic paper, or synthetic resin film. It can be printed on a base material or directly on the packaging material for items to be sterilized. The printed surface is coated with a substantially transparent synthetic resin. That is, if water resistance is imparted by coating or laminating a substantially transparent synthetic resin film using an adhesive as a medium, it can also be used as an indicator for retort sterilization processing. For the coating, use a resin that does not affect the discoloration of the indicator and has water resistance and heat resistance. For example, ethyl cellulose, nitrocellulose, butyral resin, acrylic ester resin,
Polyester resins and maleic acid resins are preferred.
In addition, as a synthetic resin film for lamination,
Examples include polyester film, polypropylene film, polyacetal film, and vinylidene chloride film.

[Effect]

The moist heat detection indicator of the present invention acts as an indicator under conditions matching the sterilization conditions in high-pressure steam sterilization treatment and the sterilization conditions in retort sterilization treatment. The color change conditions (color change temperature and time until color change) of the indicator can be arbitrarily adjusted by changing the types of bismuth compound and thiourea compound used, and the type and amount of synthetic rubber resin added. Water resistance can also be improved by coating the surface of the printed indicator with resin or laminating it with a synthetic resin film. In this case, since the inside of the processing device is under high pressure, water passes through the resin layer and reaches the composition.

【Example】

Examples of the present invention will be described below. As ink vehicles, Q Set 200 Medium (trade name, manufactured by Jujo Kako Co., Ltd.) and Hiset Mat Medium (trade name,
Nippon Grand Co., Ltd.), FBHD Medium (product name,
(manufactured by Toyo Ink Manufacturing Co., Ltd.) and Poly Ink Medium (trade name, manufactured by Nippon Grand Co., Ltd.). Example 1 Basic bismuth carbonate 20 parts by weight Carplex 2 parts Talc 2 parts by weight 2,2'-ditolylthiourea 20 parts by weight Qset 200 medium 60 parts by weight Basic bismuth carbonate, Carplex and talc were ball milled according to the above formulation. Weigh it into a pot and grind it well. Next, 2,2'-ditolylthiourea and Q Set 200 medium were added and kneaded for 48 hours to obtain an ink-like indicator composition for detecting moist heat. This composition was screen printed on high-quality paper, and the printed surface was laminated with a polyester film to produce a white indicator card. When this card was subjected to high-pressure steam sterilization treatment at 121°C, the card exhibited a grayish-brown color after 10 minutes of treatment, and turned blackish-brown after 20 minutes. This discoloration is consistent with the completion conditions for high-pressure steam sterilization. Example 2 An ink was prepared in the same manner as in Example 1, except that the amount of Qset 200 medium was changed to 30 parts by weight, and an indicator card was produced. When this card was subjected to high-pressure steam sterilization treatment at 121°C, the color changed to blackish brown after 7 minutes of treatment. Example 3 An ink was prepared in the same manner as in Example 1, except that the amount of Qset 200 medium was changed to 100 parts by weight, and an indicator card was produced. When this card was subjected to high-pressure steam sterilization at 121°C, it took 30 minutes for the card to turn blackish brown. From the results of Examples 1 to 3, synthetic rubber resin (Q
It can be seen that the time required for discoloration can be adjusted by changing the amount of SET 200 medium added. Example 4 Basic bismuth carbonate 17 parts by weight Carplex 2 parts by weight Talc 2 parts by weight 1,3-diphenyl-2-thiourea 21 parts by weight Qset 200 medium 60 parts by weight Ink of the above formulation by the same method as in Example 1 was prepared and an indicator card was obtained. When this white card was autoclaved at 110℃,
After 10 minutes of treatment, the curd took on a grayish-brown color, and after 15 minutes it turned blackish-brown. Example 5 Bismuth sesquioxide 13.5 parts by weight Talc 4.5 parts 2,2'-ditolylthiourea 17 parts by weight FBHD medium 67 parts by weight Toluene 25 parts by weight Isopropyl alcohol 15 parts by weight Bismuth sesquioxide and talc were ball milled according to the above formulation. Weigh it into a pot and grind it well. Next, 2,2'-ditolylthiourea, FBHD medium, toluene and isopropyl alcohol were weighed and thoroughly kneaded to prepare a gravure printing ink. The viscosity of this ink is approximately Zahn Cup No. 4.
It takes 20 seconds, which is suitable for gravure printing. This ink was printed on sterile paper using a gravure printing machine with a plate depth of 50 μm, and laminated in the same manner as in Example 1 to create an indicator card. When autoclaved at 121°C, the color changed from white to grayish brown after 10 minutes of treatment, and changed to blackish brown after 20 minutes of treatment. This discoloration meets the conditions for completion of high-pressure steam sterilization. Example 6 Bismuth sesquioxide 13.5 parts Talc 4.5 parts 1,3-diphenyl-2-thiourea 16 parts FBHD medium 67 parts Toluene 25 parts Isopropyl alcohol 15 parts Same as Example 5 according to the above formulation A gravure printing ink was prepared by the method. This was printed on sterile paper and laminated in the same manner as in Example 1 to create an indicator card. After high-pressure steam sterilization at 110℃,
The color changed from white to black in 15 minutes. Example 7 Basic bismuth nitrate 45 parts by weight Talc 10 parts by weight 1-phenyl-2-thiourea 20 parts by weight Qset 200 medium 150 parts by weight An ink was prepared in the same manner as in Example 1 according to the above formulation, and an ink for screen printing was prepared. Obtained. This ink was printed on UV Yubo 80FYN for Daitatsu welder (trade name, manufactured by Dainippon Ink Industries, Ltd.), and the printed surface was laminated with polypropylene laminate film SSPP20 (trade name, manufactured by FNS) to form an indicator label. This indicator label 90℃
When heated in boiling water, the color changed from yellowish white to brown in 3 minutes, and changed to black in 5 minutes. In addition, it turns brown after 1 minute in boiling water at 95℃.
The color changed to black after 3 minutes of treatment. Example 8 Basic bismuth nitrate 45 parts by weight Talc 10 parts by weight 1,3-diphenyl-2-thiourea 35 parts by weight Q Set 200 Medium 95 parts by weight According to the above formulation, an ink was prepared in the same manner as in Example 1 for screen printing. Ink was prepared and indicator cards were made. When this indicator card was heat-treated with steam at 100°C, the color changed from white to gray-brown after 10 minutes of treatment, and changed to black-brown after 15 minutes of treatment. Example 9 Basic bismuth acetate 38 parts by weight Carplex 5 parts by weight Talc 5 parts by weight 2,2'-ditolylthiourea 50 parts by weight Qset 200 medium 210 parts by weight According to the above formulation, an ink was prepared in the same manner as in Example 1 and screened. A printing ink was obtained. This ink was printed on UV Yubo 80FYN for Daitatsu Welder (trade name, manufactured by Dainippon Ink Industries, Ltd.), and the printed surface was transparently laminated to form an indicator label. When this indicator label was subjected to high-pressure steam sterilization at 121°C, the color changed from white to grayish brown after 10 minutes of treatment, and turned black after 20 minutes of treatment. These discoloration conditions meet the conditions for completion of high-pressure steam sterilization. Example 10 Basic bismuth acetate 17 parts by weight 1,3-diphenyl-2-thiourea 20 parts by weight Talc 5 parts by weight Highset pine medium 29 parts by weight Qset 200 medium 29 parts by weight Same as Example 1 according to the above formulation The ink was made into an ink using a method for screen printing. This was printed in the same manner as in Example 9 to form an indicator label. When this indicator label was subjected to high-pressure steam sterilization treatment at 121° C., the color changed from white to brown after 2 minutes of treatment, and changed to black after 5 minutes of treatment. Example 11 Basic bismuth acetate 34 parts by weight Talc 15 parts by weight 2,2'-ditolylthiourea 48 parts by weight Polyink medium 130 parts by weight An ink was prepared in the same manner as in Example 1 according to the above formulation, and an ink for screen printing was prepared. I got it. This was processed in the same manner as in Example 7 to obtain an indicator label. When this indicator label was subjected to high-pressure steam sterilization at 121°C, the color changed from white to brownish gray after 10 minutes of treatment, and changed to black after 20 minutes of treatment. Visual observation of the indicator compositions subjected to high-pressure steam sterilization treatment or heat treatment in boiling water in Examples 1 to 11 above revealed that the surfaces of all compositions were uniformly discolored, and no leakage of the compositions occurred. It wasn't recognized. Comparative Example 1 According to the conventional indicator formulation, 5g of Prussian blue,
90g of soda carbonate, 12g of rosin modified maleic acid resin
% xylene solution was kneaded in a ball mill pot to form an ink, and this ink was printed on high-quality paper to form an indicator card. When this was heat-treated in steam at 100°C, the color changed from blue to green in about 2 minutes, and then changed to yellow in 15 minutes. However, in the areas that had been in direct contact with water, some abnormalities occurred in discoloration. Since sterilization conditions in the medical field require processing in high-pressure steam at 121°C for 20 minutes, this card is unsuitable as an indicator for medical devices. Comparative Example 2 According to the conventional indicator formulation, 37.5% basic lead carbonate, 12.5% zinc sulfide, 33% chlorinated polypropylene resin varnish, and 17% toluene were kneaded in a ball mill pot to form ink, and this ink was printed on high-quality paper. and used it as an indicator card. this
When heated in high-pressure steam at 132°C, the color changed from white to black in 20 minutes. However, because this indicator requires heating at temperatures as high as 132 degrees Celsius for 20 minutes to change color, there is a risk that medical equipment may deteriorate due to heat. Furthermore, the degree of discoloration is greatly influenced by the purity of the zinc sulfide used. Furthermore, the lead compounds used may have an effect on the human body, and are used in medical and
There are problems as indicators for sterilization and sterilization used in the food field. Comparative Example 3 According to the conventional indicator formulation example, 1 part by weight of Basic Cred 37, 0.8 part by weight of caprylic acid,
A thermochromic ink was obtained by uniformly mixing 100 parts of lauric acid, 5 parts of Oil Blue #8, 5 parts of Ceres Yellow, 600 parts of ethyl cellosolve, and 200 parts of xylene. After applying this ink to high-quality paper, the temperature is 132℃.
When heat-treated in high-temperature steam, the ink became approx.
The color changed from reddish-purple to green in 30 minutes, but this discoloration condition is not practical as it may cause thermal deterioration of medical equipment.

【Effect of the invention】

As explained in detail above, the thermal detection indicator of the present invention has superior color change responsiveness and safety for the human body when sterilization conditions are completed compared to conventional indicators, and is suitable for high-pressure steam sterilization processing conditions in the medical field. It has discoloration conditions consistent with retort sterilization treatment conditions in the food field. Therefore, when sterilizing medical equipment, sanitary materials, etc. in a high-pressure steam sterilizer, or when sterilizing retort food, canned food, etc. in a sterilizer, if you put this together with the object to be sterilized, the indicator will not change color. By observing this, it can be easily detected whether the contents have been sterilized and sterilized under appropriate conditions, which is extremely effective in controlling the sterilization process.

Claims (1)

[Claims] 1. One or more water-insoluble or slightly soluble bismuth compounds selected from bismuth sesquioxide, basic bismuth carbonate, bismuth hydroxide, basic bismuth nitrate, and basic bismuth acetate, and thiourea, methylthiourea, and ethylthiourea. , trimethylthiourea, tolylthiourea, diphenylthiourea, ditolylthiourea, phenylthiourea, methylolthiourea, and a synthetic rubber resin.
An indicator for detecting heat and humidity, characterized in that a sheet base material is coated with a substantially transparent synthetic resin.