JP2007092207A - Bleaching method using microbubble - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bleaching method having excellent bleaching effects for clothing or the like and slight in environmental burden. <P>SOLUTION: The bleaching method involves combinational use of microbubbles in making a bleaching using hydrogen peroxide and ionic crystal. In this method, it is preferable that the microbubbles be generated using a pneumatically shearing-type apparatus. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a bleaching method using a hydrogen peroxide-based bleaching solution excellent in cleaning and bleaching power and microbubbles. The method of the present invention is used for washing and bleaching purposes.

  Cleaning and bleaching agents are roughly classified into chlorine bleaches and hydrogen peroxide bleaches. Chlorine based on sodium hypochlorite is used for bleaching clothing or mold on household walls and furniture because of its strong bleaching power. However, although the chlorine system is excellent in bleaching power, it has the disadvantages of discoloring clothes and generating a peculiar odor due to molecular chlorine, causing discomfort to the user. There is also a risk of poisoning by chlorine gas if used incorrectly.

  On the other hand, the amount of hydrogen peroxide-based is increasing mainly for household use because it has a wider range of use as a bleaching agent and has no unpleasant odor compared to chlorine-based. However, hydrogen peroxide alone is inferior in bleaching power, and bleaching power is low for bleaching clothing at low temperatures or bleaching furniture walls, especially sinks, bathroom walls, ceilings or tile joints. It is insufficient. Therefore, various compounds are generally added to the hydrogen peroxide bleaching agent for the purpose of improving the bleaching power.

  As the bleaching power improver, for example, as disclosed in Patent Document 1, an organic compound having a nitrile group such as p-chlorobenzoylcyanamide is used. However, as is well known, an organic compound having a nitrile group is not easily decomposed in an ecosystem, and it is clear that its use is not preferable from the viewpoint of reducing the environmental load in recent years.

  For the purpose of sterilization, a technique for supplying ozone gas to a microbubble generator is disclosed in Patent Document 2. However, in this method, in addition to the microbubble generator, an ozone gas generator must be provided, which is economical. It's not a good idea.

  In addition, for the purpose of treating a hardly decomposable substance, a technique of using hydrogen peroxide and ozone microbubbles in combination is disclosed in Patent Document 3, but in this method, in addition to the microbubble generator, an ozone gas generator It is not an economic solution.

Washing machines aimed at improving the cleaning power due to fine bubbles are also on the market, but the principle of foam generation is the mechanical stirring method, the surface of the fine bubbles is not charged, there is no adsorption action to dirt, The cleaning effect is small.
JP-A-52-52880 JP 2004-321959 A JP 2003-190909 A

  An object of the present invention is to provide a bleaching method which has an excellent effect on bleaching of clothing and the like and has a low environmental load in view of the situation as described above.

  As a result of intensive studies on the above problems, the present inventors have used a bleaching solution containing microbubbles generated using hydrogen peroxide, ionic crystals, and an air shearing type microbubble generator. The inventors have found that high activity can be obtained for washing and bleaching of clothing and the like without using an organic compound or ozone gas, and have completed the present invention. That is, the present invention relates to a bleaching method using microbubbles when bleaching using hydrogen peroxide and ionic crystals.

  According to the present invention, it is possible to perform bleaching using a hydrogen peroxide bleaching solution having a low environmental load.

  As the hydrogen peroxide, a commercially available aqueous hydrogen peroxide solution can be used. There is no restriction | limiting in particular in the density | concentration of hydrogen peroxide, and it can decide arbitrarily by the washing | cleaning and bleaching material made into object. The treatment temperature is not limited, but the higher the temperature, the faster the decomposition rate of hydrogen peroxide.

  The ionic crystal in the present invention is not particularly limited as long as it is an ionic crystal, and various sodium salts such as sulfuric acid, nitric acid, hydrochloric acid or carbonic acid, potassium salts, calcium salts and the like are preferably used. There is no restriction | limiting also in the density | concentration of an ionic crystal, It can determine arbitrarily within the range of solubility.

  Moreover, in this invention, arbitrary pH can be selected according to the intended purpose. Any compound may be used to control the pH. For acids, mineral acids such as sulfuric acid and hydrochloric acid, and organic acids such as acetic acid and propionic acid can be used. For bases, ammonia and alkali hydroxide can be used. Further, amines can be used.

  As the microbubble, a Taisei type using an air shear flow (developed by Tokuyama National College of Technology, Professor Hirofumi Taisei) and an OHR fluid engineering laboratory type nozzle are preferably used. There is no restriction | limiting in particular also in the temperature at the time of generating microbubble, If it is below the boiling point of a solution, it can implement. There is no restriction | limiting also in the kind of gas which forms a microbubble, Gas other than air can also be used.

  The present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited by these examples.

The decolorization test in Examples and Comparative Examples was evaluated by the following evaluation method.
The liquid to be tested was stained with methylene blue, and the change in concentration before and after the treatment was calculated as the decomposition rate of methylene blue. The concentration of methylene blue was measured at a wavelength of 660 nm using Ubest-35 manufactured by JASCO Corporation.
Decomposition rate of methylene blue = (concentration before test−concentration after test) / (concentration before test) × 100 (%)

Example 1
A microbubble generator equipped with a water tank, a cooling pipe, a pump (rated capacity: 30 liters / minute), and a large nozzle (M2-M type) was used. 3 liters of an aqueous solution containing 3.5% by weight hydrogen peroxide, 10% by weight sodium sulfate and 11 ppm methylene blue was placed in the water tank, and the pump was started. The amount of air sucked into the nozzle by starting the pump was about 30 liters per hour. After 6 hours at a water bath temperature of 25 ° C., the pump was stopped and the concentration of methylene blue was determined to be 9.2 ppm and the decomposition rate of methylene blue was 16.1%.

Comparative Example 1
The experiment was performed in the same manner as in Example 1 except that an aqueous solution containing 3.5 wt% hydrogen peroxide and 11 ppm methylene blue was used in the water tank. The methylene blue concentration after 6 hours was 10 ppm, and the decomposition rate of methylene blue was 9.0%.

Claims (2)

  A bleaching method using microbubbles when bleaching with hydrogen peroxide and ionic crystals.   The bleaching method according to claim 1, wherein the microbubbles are generated by an air shear flow type apparatus.