JPH0142981B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention provides a method for sterilizing medical equipment using high-pressure steam, in which the medical equipment satisfies sufficient temperature and time conditions necessary for sterilization. This relates to indicator ink that changes color when sterilization is completed to indicate completion of sterilization.

[Background of the invention]

When sterilizing medical equipment using high-pressure steam, the medical equipment to be sterilized should be wrapped in packaging material made of paper, cloth, non-woven fabric, or other material that is highly permeable to water vapor, and then subjected to high-pressure steam sterilization while still packaged. In this case, saturated steam at the required temperature penetrates into the center of the package of the medical equipment to be sterilized, and by contacting the equipment for a certain period of time, it is possible to determine whether or not the equipment has been sterilized. , it is necessary to check each package individually.

Conventionally, a method for confirming sterilization is to use a so-called biological sterilization indicator, in which a certain number of spores of heat-resistant bacteria, which take a relatively long time to die by high-pressure steam sterilization, are attached to pieces of filter paper. A known method is to insert the indicator near the center of the package of medical equipment to be sterilized, perform high-pressure steam sterilization, remove the indicator aseptically after sterilization, and use a culture method to determine whether the heat-resistant bacteria is alive or dead. ing.

However, according to this method, it takes several days to culture the bacteria, so when using medical equipment that has been sterilized using high-pressure steam, as soon as the packaging is opened, the medical equipment must be used immediately. There is a drawback that it is not possible to determine whether or not the sterilization of the equipment is complete.

Therefore, instead of such a biological sterilization indicator, the color change is based on a chemical principle that causes a precise and clear color change when exposed to saturated steam at a certain temperature for a certain period of time. An indicator card printed with indicator ink (hereinafter referred to as indicator ink for high-pressure steam sterilization) is inserted in advance near the center of the package of medical equipment to be sterilized, and the sterilization status inside the package is determined from the degree of discoloration. Many methods are used.

This method is convenient in that when each package of sterilized medical equipment is opened, the sterilization status inside the package can be visually determined immediately.

Indicator inks for high-pressure steam sterilization used to create such indicators for high-pressure steam sterilization have conventionally been made by applying the reaction between lead chloride and zinc sulfide, as described in, for example, U.S. Pat. No. 3,360,337. , those whose color changes from white to black due to the formation of black lead sulfide during high-pressure steam sterilization, and those with basic lead carbonate and zinc sulfide as described in Japanese Patent Publication No. 51-4124. It is known that the color changes from white to black due to the formation of lead sulfide. However, it is not preferable to package a sterilization indicator using an ink containing a compound of highly toxic heavy metals such as lead with medical equipment and perform high-pressure steam sterilization because of the sanitary concerns. It is also already known that indicator inks for autoclave sterilization can be obtained by combining compounds of metals other than lead and various sulfur compounds. For example, in the above-mentioned Japanese Patent Publication No. 51-4214, page 1, right column, an indicator ink for high-pressure steam sterilization can be obtained by combining compounds such as copper, cobalt, and nickel with various sulfur compounds. If the type of combination and the vehicle used for ink preparation are not properly selected, the stability of the indicator ink itself and the shelf life of its printed matter may be poor, or the commonly used high-pressure steam sterilization conditions may be poor. It is stated that complete discoloration is unlikely to occur at 120°C to 150°C for 20 minutes.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and
The first invention is an indicator that clearly changes color when heated at 121°C to 140°C for 20 to 40 minutes, and does not cause color bleeding, due to the reaction of basic copper carbonate with low toxicity and sulfur. The aim is to provide ink.

In addition, the second invention is based on the reaction of basic copper carbonate with low toxicity and sulfuric acid at 121°C to 140°C for 20 minutes to
To provide an indicator ink that clearly changes color by heating for 40 minutes, does not cause color bleeding, and has a light color tone before changing color, making it easy to confirm the color change.

Furthermore, the third invention is a device that clearly changes color when heated at 121°C to 140°C for 20 to 40 minutes due to the reaction of basic copper carbonate with low toxicity and sulfuric acid, and there is no color bleeding. Moreover, it is an object of the present invention to provide an indicator ink whose color change sensitivity can be adjusted.

[Summary of the invention]

Experimental exploration by the inventor revealed that a mixture of basic copper carbonate and sulfur is a promising substance that exhibits a clear discoloration when stored in the temperature range of 121℃ to 140℃ for 20 to 40 minutes. did.

However, in order to put this mixture into practical use as an indicator ink, it is necessary that the above-mentioned reactants be dispersed extremely uniformly and densely in the printed film, and furthermore, these reactants must be able to discolor. It is desirable that no color bleeding occurs when this is done.

In order to improve the dispersibility of the fine particles of the reactant and to prevent color bleeding, the present inventors
The use of certain chlorinated rubbers (or chlorinated polypropylene or chlorinated polyethylene) as the vehicle for the ink and the addition of basic magnesium carbonate powder have been found to be promising. Here, the weight ratio of basic copper carbonate and sulfur as color-changing components is the equivalent of the chemical reaction, 1:
A value around 0.3 is appropriate, but there is no particular problem even if the ratio deviates from this value. Further, as the basic magnesium carbonate, precipitated magnesium carbonate is suitable because it has a small content of impurities and a fine particle size.

In order to achieve the above object based on the above-mentioned principle, the indicator ink for autoclave sterilization of the present invention contains basic copper carbonate, sulfur, and basic magnesium carbonate as main components, and contains chlorine as a binder. It is characterized by using a chlorinated polymer selected from chlorinated rubber, chlorinated polypropylene, and chlorinated polyethylene, with an average molecular weight of 60 to 71% and an average molecular weight of 3,000 to 20,000.

The commercial products of chlorinated rubber, chlorinated polypropylene, and chlorinated polyethylene mentioned above generally have a low chlorine content.
20-71%, but chemical stability, thermal softening temperature,
and 60 to 71 considering pigment dispersibility in ink.
% is appropriate. In addition, in order to maintain a relatively high ink concentration, a low viscosity product with an average molecular weight of 3,000 to 20,000 is preferable.

The basic structure of the indicator ink of the first invention is as described above, but in order to make the color tone as light as possible before discoloration and make the discoloration clear, the second invention is applied to make the color change clear. It is effective to add a pigment, for example a high refractive index pigment such as zinc oxide, in an amount of 10 to 1% by weight of the ink solids.
If the amount of the white pigment is less than 1% by weight, the effect of making the color tone before discoloration lighter is insufficient, and if it exceeds 10% by weight, the color tone after discoloration will also be made lighter, and the discoloration will become unclear. do.

In addition, the third invention is applied to control the sensitivity of the discoloration reaction to reduce discoloration at the initial stage of sterilization or to extend the time required for complete discoloration. It is also effective to add % by weight of an organic carboxylic acid as a discoloration reaction inhibitor. If the amount of the organic carboxylic acid added exceeds 2%, the color change reaction will be excessively suppressed and the color change will not be completed within the appropriate sterilization time, and if it is less than 0.2%, the effect of controlling the reaction rate by addition will not be recognized. As the above organic carboxylic acid, any of phthalic acid, phthalic anhydride, trimellitic acid, P-tert-butylbenzoic acid, lauric acid, adipic acid, and sebacic acid can be used.

As described above, the first to third inventions use chlorinated rubber, chlorinated polypropylene, or chlorinated polyethylene with a chlorine content of 60 to 71% as a binder for the ink, but instead of these binders, vinyl based resin,
If a binder such as polyester resin, cellulose resin, cyclized rubber, or chlorinated polypropylene with low chlorine content is used, the dispersibility of basic copper carbonate particles and sulfur particles in the ink will be poor. does not show uniform black color.

[Embodiments of the invention]

The present invention will be explained in more detail with reference to Examples below.

Example 1 Next, the material was weighed into a pot of a ball mill and sufficiently ground to prepare an indicator ink for high-pressure steam sterilization.

Basic copper carbonate 17.6 parts Colloidal sulfur 5.4 parts Basic magnesium carbonate 16.4 parts Chlorinated rubber 18.2 parts Aromatic hydrocarbon solvent 42.4 parts The above chlorinated rubber is Adeka Chlorinated Rubber CR-
5 [manufactured by Asahi Denka Kogyo Co., Ltd., trade name] was used. Also,
In this example, an aromatic hydrocarbon solvent was used as the solvent for preparing the ink. When carrying out the present invention, ester solvents, ketone solvents, alcohol ester solvents, or mixtures thereof can also be used as the above-mentioned solvents.

This ink was printed on card paper by silk screen printing to create an indicator card for high-pressure steam sterilization. The printed part of this indicator card was a pale grass color, but when it was sterilized with saturated steam at 121°C, it turned gray after 12 minutes of sterilization, and turned to clear black after 15 minutes of sterilization. Discolored.

Also, the printed part of this indicator card is
When sterilized with saturated steam at 135°C, the material turned gray after 3 minutes, and turned bright black after 5 minutes, which is the time required to complete sterilization. Furthermore, the printed portion of this indicator card did not transfer to and contaminate other surrounding objects during the sterilization process.

Example 2 The following materials were weighed into a pot of a ball mill and thoroughly ground to prepare an indicator ink for high-pressure steam sterilization.

Basic copper carbonate 17.6 parts Colloidal sulfur 5.4 parts Basic magnesium carbonate 16.4 parts Chlorinated polypropylene 18.2 parts Aromatic hydrocarbon solvent 42.4 parts The above chlorinated polypropylene is Superchron 306 [manufactured by Sanyo Kokusaku Pulp Co., Ltd., trade name] When an indicator card was prepared in the same manner as in Example 1 and tested in the same manner as in Example 1, it exhibited the same color change performance as in Example 1 described above.

Example 3 Next, the material was weighed into a pot of a ball mill and thoroughly ground to prepare an indicator ink for high-pressure steam sterilization.

Basic copper carbonate 17.6 parts Colloidal sulfur 5.4 parts Basic magnesium carbonate 16.4 parts Chlorinated polyethylene 18.2 parts Aromatic hydrocarbon solvent 42.4 parts The above chlorinated polyethylene is Super Chron 507 [manufactured by Sanyo Kokusaku Pulp Co., Ltd., trade name] using
When an indicator card was prepared in the same manner as in Example 1 and subjected to the same test, it exhibited the same discoloration performance as in Examples 1 and 2 described above.

Comparative Example 1 The following materials were weighed into a pot of a ball mill and thoroughly ground to prepare an indicator ink for high-pressure steam sterilization.

Basic copper carbonate 17.6 parts Colloidal sulfur 5.4 parts Basic magnesium carbonate 16.4 parts Chlorinated polypropylene 18.2 parts Aromatic hydrocarbon solvent 42.4 parts The above chlorinated polypropylene is Hardlene 17LLB (trade name) with a chlorine content of 34-35%. was used.

The ink of Comparative Example 1 was used to print on card paper using a silk screen printing method to create an indicator card for high-pressure steam sterilization.

This indicator card was a pale grass color before changing color.

And this indicator card (comparative example)
When heat treated with saturated steam at 121° C. for 20 minutes, the color changed to grayish black, but did not exhibit the sharp black color as in Examples 1, 2, and 3.

Furthermore, because the heat softening temperature of the binder was low, the discolored portion of the indicator card was transferred to medical equipment, causing stains.

Comparative Example 2 The following materials were weighed into a pot of a ball mill and thoroughly ground to prepare an indicator ink for high-pressure steam sterilization.

Basic copper carbonate 17.6 parts Colloidal sulfur 5.4 parts Basic magnesium carbonate 16.4 parts Chlorinated polypropylene 18.2 parts Aromatic hydrocarbon solvent 42.4 parts The above-mentioned chlorinated polypropylene is Super Chron 804M (trade name) with a chlorine content of 34-35%. was used.

The ink of Comparative Example 2 was used to print on card paper using a silk screen printing method to create an indicator card for high-pressure steam sterilization.

This indicator card was a pale grass color before changing color.

And this indicator card (comparative example 2)
When it was heat-treated with saturated steam at 121° C. for 20 minutes, the color changed to gray-black, but it did not exhibit the sharp black color as in Examples 1, 2, and 3.

Furthermore, because the heat softening temperature of the binder was low, the discolored portion of the indicator card was transferred to medical equipment, causing stains.

From the experimental results of Comparative Examples 1 and 2 mentioned above, it can be seen that the chlorinated polymer used as a binder has no practical value if the chlorine content is too small. The present inventor conducted comparative experiments on chlorinated polymers with various chlorine contents, and as a result, confirmed that a range of 60 to 71% is suitable.

Comparative Example 3 The following materials were weighed into a pot of a ball mill and thoroughly ground to prepare an indicator ink for high-pressure steam sterilization.

Basic copper carbonate 21.7 parts Colloidal sulfur 6.5 parts Chlorinated rubber 26.0 parts Aromatic hydrocarbon solvent 45.8 parts That is, in Comparative Example 3, basic magnesium carbonate was removed from the ingredients in Example 1, and other The brands of drugs were the same as in Example 1.

This ink was printed on card paper by silk screen printing to create an indicator card for high-pressure steam sterilization. The color of the printed part of this indicator card is pale grass green, and it changes to black after high-pressure steam sterilization, but the color is not clear and
Black bleeding occurred on the outside around the printed area.

The experimental results of Comparative Example 3 show that unless an appropriate amount of basic magnesium carbonate is added, the performance as an indicator ink will be significantly lowered and the ink will be impractical.

Comparative Example 4 Therefore, instead of the basic magnesium carbonate described above, silica having similar properties was used to prepare an indicator ink with the following formulation.

Basic copper carbonate 14.3 parts Colloidal sulfur 4.3 parts Silica 2.8 parts Chlorinated rubber 15.7 parts Aromatic hydrocarbon solvent 62.8 parts As the silica, Aerosil R-972 (trade name) was used in Comparative Example 4. Other drug brands were the same as in Example 1.

This ink was printed on card paper using a silk screen printing method to create an indicator card for high-pressure steam sterilization. The color of the printed part of this indicator card is pale grass green, and the color change when high-pressure steam sterilization is similar to that of Comparative Example 3, and the color changes to black, but the color tone is as clear as Example 1. However, color bleeding occurred around the printed area.

The experimental results of Comparative Example 4 show that blending an appropriate amount of basic magnesium carbonate is necessary to obtain practical performance, and that silica cannot be substituted.

Example 4 Next, as an experiment to make the discoloration of the indicator ink of the present invention more obvious and to control the discoloration speed, the following materials were weighed into a pot of a ball mill and sufficiently ground to make an indicator for high-pressure steam sterilization. Created ink.

Basic copper carbonate 17.0 parts Colloidal sulfur 5.2 parts Basic magnesium carbonate 12.9 parts Activated zinc white 3.4 parts Phthalic anhydride 0.3 parts Chlorinated rubber 20.4 parts Aromatic solvent 40.8 parts Chlorinated rubber CR-5 (trade name) was used. This ink was printed on card paper by silk screen printing to create an indicator card for high-pressure steam sterilization. The color of the printed part of this indicator card was a lighter grass color than that of the card obtained in Example 1, but it turned gray after 15 minutes of high-pressure steam sterilization at 121°C, and the sterilization process was slow. The color changed to a clear black within 20 minutes, which can be done reliably, and the black color remained almost constant even after longer sterilization times.

In this Example 4, the color tone before discoloration was lighter than that in Example 1, which is considered to be the effect of adding zinc oxide.

As a result of experiments with various amounts of active zinc white added, the present inventor found that 1% by weight based on the solid components of the ink.
It was confirmed that the effect of lightening the color tone before discoloration was not observed in the following, and when it exceeded 10% by weight, the clarity of black color after discoloration was impaired.

Furthermore, the reason why the discoloration speed in Example 4 was slightly slower than that in Example 1 is considered to be due to the addition of phthalic anhydride.

In addition to phthalic anhydride, the present inventor has discovered that, in addition to phthalic anhydride, phthalic acid, trimellitic acid, P-tert-butylbenzoic acid, lauric acid, adipic acid, zebacic acid, etc.
As a result of experiments with the addition of various organic carboxylic acids,
It was confirmed that the sensitivity could be adjusted within a practically suitable range by adding 2 to 0.2% of organic carboxylic acid.

In addition, the indicator card in Example 4 was still gray after 4 minutes of high-pressure steam sterilization at 135°C, but it changed to a clear black color after 6 minutes, when sterilization was carried out with sufficient time and reliability. Even after the above sterilization time, almost constant black color was maintained.

Furthermore, during the above sterilization process, the indicator ink printed portion of the indicator card did not transfer to other surrounding objects and contaminate them.

〔Effect of the invention〕

As detailed above, the indicator ink for high-pressure steam sterilization of the first invention does not contain toxic metals such as lead, clearly changes color when the temperature and time appropriate for high-pressure steam sterilization are satisfied, and Since there is no color bleeding, it has an excellent practical effect of being able to reliably indicate the completion of the sterilization operation.

Furthermore, the indicator ink for high-pressure steam sterilization of the second invention does not contain toxic metals such as lead, changes color clearly when the temperature and time appropriate for high-pressure steam sterilization are satisfied, and furthermore, the color tone before the change of color changes. Since it is light in color, it is easy to check for discoloration, and since there is no color bleeding, it has an excellent practical effect of being able to reliably indicate the completion of the sterilization operation.

Furthermore, the indicator ink for high-pressure steam sterilization of the third invention does not contain toxic metals such as lead, changes color clearly when the temperature and time appropriate for high-pressure steam sterilization are satisfied, and furthermore, the color change sensitivity can be adjusted. In addition, since there is no color bleeding, the completion of the sterilization operation can be reliably indicated, which is an excellent practical effect.

Claims (1)

[Scope of Claims] 1. Chlorinated rubber, chlorinated polypropylene, which contains basic copper carbonate, sulfur, and basic magnesium carbonate as main components, has a chlorine content of 60 to 71% as a binder, and has an average molecular weight of 3,000 to 20,000. An indicator ink for high-pressure steam sterilization characterized by using a chlorinated polymer selected from chlorinated polyethylene. 2. Chlorinated rubber, chlorinated polypropylene, and chlorinated polyethylene with basic copper carbonate, sulfur, and basic magnesium carbonate as main components, chlorine content of 60 to 71% as a binder, and average molecular weight of 3,000 to 20,000. An indicator ink for high-pressure steam sterilization, characterized in that it uses a selected chlorinated polymer and contains 10 to 1% by weight of zinc oxide based on the solid components of the ink. 3. Chlorinated rubber, chlorinated polypropylene, and chlorinated polyethylene with basic copper carbonate, sulfur, and basic magnesium carbonate as main components, chlorine content of 60 to 71% as a binder, and average molecular weight of 3,000 to 20,000. An indicator ink for high-pressure steam sterilization characterized by using a selected chlorinated polymer and adding 2 to 0.2% by weight of an organic carboxylic acid based on the solid components of the ink as a color change rate regulator.