JPH0815228A - Dispersant for magnetic particle solution used for wet type magnetic particle crack detection testing method - Google Patents

Abstract

PURPOSE:To provide a dispersant used for a wet type magnetic particle crack detection testing method in which the length of the antifoaming persistence can be controlled. CONSTITUTION:In a dispersant for a magnetic particle solution used for a wet type magnetic particle crack detection testing method, which comprises 70-98wt.% water or powder formed by particles dissolved in water and 2-30wt.% nonionic surface active agent with HLB of 8-14, one or two or more nonionic surface active agents selected from,polyoxyethylene alkylether type nonionic surface active agent, a polyoxyethylene alkyl arylether type nonionic surface active agent, a polyoxyethylene alkylester type nonionic surface active agent, a polyoxyethylene alkylamine type nonionic surface active agent, and a polyoxyethylene sorbitan fatty acis ester type nonionic surface active agent and a polyoxyethylene polyoxypropylene alkylether type nonionic surface active agent are used jointly and the antifoaming persistence depending on the compounding ratio of both agents is given to the dispersant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic powder liquid dispersant used in a wet magnetic powder flaw detection test method. INDUSTRIAL APPLICABILITY The dispersant for magnetic powder liquid according to the present invention can control defoaming persistence and is used in a wet magnetic powder flaw detection test method carried out in the steel industry, the automobile industry and the like.

[0002]

2. Description of the Related Art As is well known, in the steel industry, steel materials such as square billets and round billets are inspected, and in the automobile industry, steel parts such as knuckle arms and shafts are inspected. The "wet magnetic powder flaw detection test method" is widely used for partial flaw detection. The wet magnetic powder flaw detection test method is usually 0.2% non-fluorescent magnetic powder or fluorescent magnetic powder per liter of water.
It is carried out by contacting the surface of the object to be inspected with a magnetic powder liquid in which ˜15 g is dispersed. In preparing the magnetic powder liquid, a “dispersing agent for magnetic powder liquid” containing a surfactant is used.
Is always used.

Incidentally, JIS G 0565-1992
"(Magnetic powder flaw detection test method for iron and steel materials and classification of magnetic powder pattern)" states that "... for the wet method, ... Use a test liquid containing water as a dispersion medium and, if necessary, an appropriate surfactant ...." However, in preparing a magnetic powder liquid by dispersing non-fluorescent magnetic powder or fluorescent magnetic powder in water, it is essential to use a dispersing agent for magnetic powder liquid containing a surfactant as described above. This is a common general knowledge of those skilled in the art.

At present, the basic formulation of a commercially available magnetic powder liquid dispersant is 70 to 98% by weight of water and 8 to 14 of HLB.
Within the range of polyoxyethylene alkyl ether type nonionic surfactants, polyoxyethylene alkylallyl ether type nonionic surfactants, polyoxyethylene alkyl ester type nonionic surfactants, polyoxyethylene alkylamine type nonionic surfactants One or two or more nonionic surfactants selected from surfactants and polyoxyethylene sorbitan fatty acid ester type nonionic surfactants in an amount of 2 to 30% by weight are dissolved or dispersed, and if necessary, , A commercially available emulsion type antifoaming agent (for example, “Silicone antifoaming agent KM-7
1 "," silicone defoaming agent KM-75 ": trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and commercially available rust inhibitors (for example, sodium nitrite, triethanolamine) are added in appropriate amounts. In the above-mentioned basic formulation, the content of the nonionic surfactant is 2 to 30% by weight is 2% by weight.
If it is less than 30% by weight, the non-fluorescent magnetic powder or fluorescent magnetic powder in the prepared magnetic powder liquid cannot be sufficiently dispersed, and if it exceeds 30% by weight, the viscosity becomes high and it is difficult to become a liquid substance. is there. In addition, in the formulation to which the silicone defoaming agent or the rust preventive agent was added, the amount of water commensurate with the amount added was reduced.

Various improved formulations of magnetic powder liquid dispersants have also been proposed, and Japanese Patent Publication No. 2-59426 discloses water,
A nonionic surfactant, a silicon defoaming agent, a rust preventive and a dimethylpolysiloxane-polyoxyalkylene copolymer are disclosed in Japanese Patent Publication No. 2-594267.
What is composed of water, a nonionic surfactant, a silicone defoaming agent and soap is disclosed in Japanese Patent Publication No. 26057/1992.
Each of water, a nonionic surfactant, a silicone antifoaming agent, soap and alcohol is disclosed.

The above-mentioned commercially available magnetic powder liquid dispersants and the magnetic powder liquid dispersants disclosed in the above-mentioned publications, for example, prepare magnetic powder liquids in which 0.2 to 2 g of fluorescent magnetic powder are dispersed per liter of water. In this case, the active ingredient (nonionic surfactant or the like) of the dispersant for a magnetic powder liquid is usually added in an amount of 1 to 3% per liter of water. This is 0.2 per 1 liter of water
In order to obtain sufficient dispersibility to disperse ~ 2 g of fluorescent magnetic powder and to obtain wettability to uniformly wet the surface of the object to be inspected when the magnetic powder liquid is brought into contact with the surface of the object to be inspected, at least 1 l of water is used.
It is necessary that the concentration of the active ingredient of the dispersant for magnetic powder liquid per 1% is 1% or more, while the concentration of the active ingredient of the dispersant for magnetic powder liquid per 1 liter of water is 3% or more. This is because no significant improvement is recognized.

[0007]

The above-mentioned conventional dispersants for magnetic powder solutions have the following problems. First, in the steel industry, when the wet magnetic powder flaw detection test method is performed with square billets or round billets as the inspected object, the inspected object is large, so it is sprayed / collected / re-sprayed / collected ... Since the spray drop distance from the spraying location of the magnetic powder used to the tray to be collected is long and the drop is large, the magnetic powder in use often foams, and the generated foam shows a defect pseudo pattern and causes an inspection error. As a dispersant for the magnetic powder liquid used in the preparation of the magnetic powder liquid in this case, one having a long defoaming persistence (one having a long foaming suppression time of the prepared magnetic powder liquid)
Is required. In order to make the dispersant for the magnetic powder liquid long-lasting defoaming, A. A method of reducing the blending ratio of the nonionic surfactant in the formulation, or B. A method of adding the emulsion-type silicone to the formulation may be adopted, and as the blending ratio of the nonionic surfactant is reduced and the addition amount of the emulsion-type silicone is increased, the defoaming duration is maintained. The sex can be lengthened. However, when the method of A is adopted, the dispersibility and wettability of the prepared magnetic powder liquid deteriorates as the blending ratio of the nonionic surfactant decreases, and thus it cannot be used as a magnetic powder liquid dispersant. When adopting the method of Otsu, the amount of scum due to the separation of silicone oil in the magnetic powder liquid prepared increases as the amount of emulsion type silicone added increases. Stability on storage will decrease.

On the other hand, when the wet magnetic powder flaw detection test method is carried out in the automobile industry using a knuckle or a shaft as the inspection object, the inspection object is relatively small and the above-mentioned head is small. It rarely foams during use, but it is required that the inspected product is a completed or semi-finished product and the surface skin is smooth, so that the wettability of the magnetic powder liquid is excellent. Therefore, the magnetic powder liquid dispersant used in the preparation of the magnetic powder liquid in this case is required to be able to prepare a magnetic powder liquid having excellent wettability, and the square billet or the round billet described above is to be inspected. Defoaming persistence is not required as much as it is. In order to obtain a magnetic powder liquid having excellent wettability, a dispersant for magnetic powder liquid can be prepared. A method of increasing the blending ratio of the nonionic surfactant in the formulation may be adopted. The more the blending ratio of the nonionic surfactant is increased, the more wettable the magnetic powder liquid can be prepared. However, when adopting the method of Hei, since the nonionic surfactant is a substance that has a substantially strong foaming property, it is possible to avoid the foaming of the magnetic powder liquid during use even if the inspection object is relatively small. Since there is no,
You will be forced to use your method.

Therefore, in order to provide a magnetic powder liquid dispersant that meets the requirements of both industries, pay close attention to the blending ratio of the nonionic surfactant and the addition amount of the emulsion type silicone. There is a problem of having to formulate the prescription, and even when the prescription considered to be optimal is prepared, the dispersibility and wettability of the magnetic powder liquid prepared using the magnetic powder liquid dispersant are not sufficient, or foaming occurs. There are problems that the suppression time is short and the amount of scum generated is large. The present invention has a first technical problem to solve the above problems.

[0010] Next, in the industry, it is normally traded in the form of filling a 18 l can (petroleum can) with a dispersant for a magnetic powder solution (weight including tare: about 20 kg), to a steel factory or an automobile factory. Since the delivery is carried out in units of 50 to 60 cans at a time, its bulk and weight are a problem. The above-mentioned problems can be solved by preparing a dispersant for a magnetic powder liquid at a site (for example, a steel factory) where the wet magnetic particle flaw detection test method is carried out, but the preparation at the site is not carried out. The reason is that the nonionic surfactants of HLBs 8 to 14 which are practically used as a dispersant for magnetic powder liquids are liquid substances, and it is very troublesome to dissolve or disperse them in water.

More specifically, when a certain amount of nonionic surfactant (liquid substance) of HLB 8 to 14 is to be dissolved or dispersed in a certain amount of water to be diluted, a certain amount of the active agent (for example, 2 g). When a certain amount (eg 98 ml) of water is injected at once into), it becomes a gel no matter how much it is stirred and the viscosity does not decrease forever, while a certain amount (eg 2 g) of the active agent When water (for example, 98 ml) is added little by little (for example, 10 ml) while stirring,
Initially, the viscosity increases and becomes a milky white dispersion liquid or jelly, but when it passes a certain point, the viscosity decreases and it becomes a translucent dispersion liquid or a transparent solution. When the HLB number of the activator is low, it becomes a milky white dispersion liquid, and when the HLB number is high, it becomes jelly-like. Therefore, it is almost impossible to dissolve or disperse the nonionic surfactants of HLB 8 to 14 in water to prepare a dispersant for a magnetic powder solution at the above-mentioned site. Prepare a transparent solution or translucent dispersion in advance on the side, as described above,
The current situation is that they are delivered in 18-liter cans.

The nonionic surfactants of HLBs 16 to 18 include powdery and flaky ones.
Non-fluorescent magnetic powder or fluorescent magnetic powder cannot be dispersed with an LB value. The present invention provides a solution to the above problems as a second technical problem.

[0013]

[Means for Solving the Problems] First, the present inventor has conducted systematic experiments on a large number of surfactants in order to achieve the above-mentioned first technical problem. When a polyoxyethylene polyoxypropylene alkyl ether type nonionic surfactant is added to the basic formulation of a dispersion for magnetic powder, the defoaming persistence becomes longer almost in proportion to the amount (suppression of foaming of the prepared magnetic powder). The wettability of the prepared magnetic powder liquid deteriorates with time, but the wettability of the prepared magnetic powder liquid is not so bad as compared with the extent that the defoaming sustainability is long, and the performance that can be used practically is maintained. And finds a striking fact that dispersion is not affected.

The first technical problem can be achieved by the present invention I as follows based on the above findings. That is, the present invention I is a dispersant for a magnetic powder liquid used in a wet magnetic powder flaw detection test method, which comprises dissolving or dispersing 2 to 30 wt% of a nonionic surfactant of HLB 8 to 14 in 70 to 98 wt% of water, As the nonionic surfactant, a polyoxyethylene alkyl ether type nonionic surfactant,
From polyoxyethylene alkyl allyl ether type nonionic surfactants, polyoxyethylene alkyl ester type nonionic surfactants, polyoxyethylene alkylamine type nonionic surfactants and polyoxyethylene sorbitan fatty acid ester type nonionic surfactants One or more selected nonionic surfactants and polyoxyethylene polyoxypropylene alkyl ether type nonionic surfactants are used in combination to impart defoaming sustainability according to the blending ratio of the two, and if necessary. A self-emulsifying silicone defoaming agent made of polyoxyalkylene-modified silicone is added in an amount of 0.1 to 10% by weight, which is a dispersant for a magnetic powder liquid used in a wet magnetic powder flaw detection test method.

Next, in order to achieve the above-mentioned second technical problem, the present inventor has made various investigations as to a means capable of reducing the bulk and weight of the dispersant for a magnetic powder liquid, and as a result, has investigated the conventional magnetic powder. By using "powder" as the medium instead of "water" as the medium of the active ingredient (nonionic surfactant, etc.) for the liquid dispersant, the volume and weight can be dramatically reduced. The idea was realized and the object was achieved by embodying this idea by using a powder composed of particles that dissolve in water.

The second technical problem can be achieved by the present invention II as follows based on the above idea. That is, the present invention II is based on 70 to 98% by weight of a powder composed of water-soluble particles and 2 to 30% of HLB 8 to 14 nonionic surfactants.
In a magnetic powder liquid dispersant used in a wet magnetic powder flaw detection test method which absorbs or adsorbs wt%, a polyoxyethylene alkyl ether type nonionic surfactant, polyoxyethylene alkyl allyl ether is used as the nonionic surfactant. 1 or 2 or more selected from a nonionic surfactant of polyoxyethylene alkyl ester type, a nonionic surfactant of polyoxyethylene alkylamine type, a nonionic surfactant of polyoxyethylene alkylamine type and a polyoxyethylene sorbitan fatty acid ester type nonionic surfactant The nonionic surfactant and the polyoxyethylene polyoxypropylene alkyl ether type nonionic surfactant are used in combination to impart defoaming persistence according to the blending ratio of the both.
If necessary, a self-emulsifying type silicone defoaming agent consisting of polyoxyalkylene-modified silicone 0.1 to 10% by weight
Is a dispersant for a magnetic powder used in a wet magnetic powder flaw detection test method.

The structures of the present invention I and the present invention II (hereinafter, both inventions may be collectively referred to as "the present invention") will be described in more detail as follows. The formulation of the magnetic powder liquid dispersant according to the present invention I is as follows: HLB 8 to 1 in 70 to 98% by weight of water.
2 to 30% by weight of the nonionic surfactant of No. 4 is dissolved or dispersed, and a polyoxyethylene alkyl ether type nonionic surfactant (for example, Neugen E).
T115: trade name: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., polyoxyethylene alkylallyl ether type nonionic surfactant (for example, Newcol 864: trade name: manufactured by Nippon Emulsifier Co., Ltd., Sunmor N-60S: trade name) :
Nika Chemical Co., Ltd.), polyoxyethylene alkyl ester type nonionic surfactant (for example, Newcol 150: trade name: Nippon Emulsifier Co., Ltd.), polyoxyethylene alkylamine type nonionic surfactant (for example, Newcol 405: Trade name: manufactured by Nippon Emulsifier Co., Ltd.) and polyoxyethylene sorbitan fatty acid ester type nonionic surfactant (for example, Sorgen T)
W60: trade name: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), in that one or more nonionic surfactants (hereinafter sometimes referred to as “common nonionic surfactants”) are used, This is common with the above-mentioned basic formulation of the conventional commercially available magnetic powder liquid dispersant.

Further, the formulation of the magnetic powder liquid dispersant according to the present invention II is such that 70 to 98% by weight of the medium is mixed with 2 to 30% by weight of the nonionic surfactant of HLB 8 to 14 and the commonly used nonion. The fact that a surfactant is used is common to the above-described basic formulation of the conventional commercially available magnetic powder liquid dispersant.

However, the formulation of the magnetic powder liquid dispersant according to the present invention has been described above in that the conventional nonionic surfactant and the polyoxyethylene polyoxypropylene alkyl ether type nonionic surfactant are used in combination. It is different from the conventional basic formulation of a magnetic powder liquid dispersant and the formulation of each magnetic powder liquid dispersant disclosed in the above-mentioned respective publications.

The polyoxyethylene polyoxypropylene alkyl ether type nonionic surfactant used in the present invention (hereinafter sometimes referred to as "controlling nonionic surfactant") has an HLB value within the range of 8 to 14. A certain liquid substance, for example, Pluronic L-44 (trade name: manufactured by Asahi Denka Co., Ltd.), New Pole PE-64 (trade name:
Commercial products such as Sanyo Chemical Industry Co., Ltd.) and Epan 410 (trade name: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) can be mentioned. As far as the inventor is aware, there is no example in which this product is incorporated in the formulation of the magnetic powder liquid dispersant, and as shown in Comparative Examples below, when this product is used alone, the magnetic powder is dispersed. It is thought that it is impossible to make it.

In the present invention, the compounding ratio of the conventional nonionic surfactant and the controlling nonionic surfactant is 1: 9.
It is selected in the range of 9: 1. The larger the blending ratio of the controlling nonionic surfactant, the longer the defoaming durability of the magnetic powder liquid dispersant becomes (the longer the foaming suppression time of the prepared magnetic powder liquid becomes), but Wettability deteriorates. However, when the magnetic powder liquid dispersant does not require so much wettability of the magnetic powder liquid, for example, when the surface condition of the object to be inspected is a rough surface or when it is not required to detect an extremely fine defect portion, , Can be put to practical use. The smaller the compounding ratio of the controlling nonionic surfactant, the shorter the defoaming persistence of the magnetic powder liquid dispersant (the shorter the foaming suppression time of the prepared magnetic powder liquid), but The wettability becomes excellent, and when the magnetic powder liquid dispersant requires wettability of the magnetic powder liquid, for example, when the surface state of the object to be inspected is a smooth surface or even very minute defects are detected. It is suitable when it is required to do so.

Therefore, in carrying out the present invention, by selecting the compounding ratio of the conventional nonionic surfactant and the controlling nonionic surfactant within the above range, the dispersion for magnetic powder liquid according to various uses can be obtained. The agent can be obtained.

The basic prescription of the magnetic powder liquid dispersant according to the present invention I is 70 to 98% by weight of water and a blending ratio selected from the above range of a conventional nonionic surfactant and a controlling nonionic surfactant. It is composed of 30% by weight. When the total amount of the conventional nonionic surfactant and the controlling nonionic surfactant is less than 2% by weight, the non-fluorescent magnetic powder or the fluorescent substance in the magnetic powder liquid prepared in the same manner as in the case of the conventional commercially available magnetic powder liquid dispersant is used. The magnetic powder cannot be sufficiently dispersed, and if it exceeds 30% by weight, the viscosity becomes high and it is difficult to form a liquid substance.

The basic formulation of the dispersant for a magnetic powder liquid according to the present invention II is 70 to 98% by weight of powder consisting of particles soluble in water and a blending ratio selected from the above range of a conventional nonionic surfactant and a control agent. It is composed of 2 to 30% by weight of a nonionic surfactant. If the total amount of the nonionic surfactant for control and the nonionic surfactant for control is less than 2% by weight, the non-fluorescent magnetic powder or fluorescent magnetic powder in the prepared magnetic powder liquid cannot be sufficiently dispersed, and 30% by weight. If it exceeds, the fluidity of the powder composed of particles that dissolve in water decreases, and the handleability deteriorates.

The powder consisting of water-soluble particles in the present invention II is the existing organic particle powder and inorganic particle, which can absorb or adsorb the nonionic surfactant of HLB 8 to 14 on the particle surface, and Any particles that do not adversely affect other components (nonionic surfactants, etc.) and the non-fluorescent magnetic powder or the fluorescent magnetic powder may be used. Examples of such particle powder include the following powders. Organic particle powder: glucose, methyl cellulose, carboxymethyl cellulose,
Hydroxyethyl cellulose, hydroxypropyl cellulose, ethylenediaminetetraacetic acid, sodium benzoate, sodium gluconate, glucose, etc. Inorganic particle powder: sodium nitrite, sodium silicate, sodium bicarbonate, sodium hexametaphosphate, sodium acid pyrophosphate, sodium acid metaphosphate, sodium tripolyphosphate, sodium phosphate,
Sodium pyrophosphate, sodium molybdate, etc. Each of the above-mentioned particle powders may be single (one kind) or mixed (two or more kinds).
However, in both cases, in terms of handling,
It is preferable to select one that passes through a 5-mesh screen. When powders having a rust preventive action such as sodium benzoate, sodium gluconate, sodium nitrite, and sodium hexametaphosphate are used from the above particle powders, the powders are a medium and at the same time It will also serve as a rust agent.

In the practice of the present invention, when it is required to prolong the antifoaming property, a self-emulsifying silicone antifoaming agent comprising a polyoxyalkylene-modified silicone is added in an amount of 0.1 to 10% by weight. can do. The self-emulsifying silicone antifoaming agent is a silicone polymer obtained by substituting a part of methyl groups of dimethylpolysiloxane with a hydrophilic polyoxyalkylene group, and is a commercially available self-emulsifying silicone antifoaming agent XS64-A9512 (commercial product). Name: Toshiba Silicone Co., Ltd.) and self-emulsifying silicone defoamer X-
The 50 series (trade name: manufactured by Shin-Etsu Chemical Co., Ltd.) is a typical product. The self-emulsifying silicone defoamer is
Compared with the commercially available emulsion type silicone defoaming agent, it has more excellent defoaming property, and the amount of scum generated during use is reduced as much as possible as shown in Examples below. It has the characteristic of being able to If the addition amount is less than 0.1% by weight, it is difficult to obtain the defoaming effect, and it is usually sufficient to add 4 to 8% by weight, and it is not necessary to add more than 10% by weight.

Further, in carrying out the present invention, the above-mentioned commercially available rust preventive which has been added to conventional dispersants for magnetic powder liquid can be added, if necessary, and the addition amount is in accordance with a conventional method. It is in the range of 0.1 to 5% by weight. 0.1% by weight
If it is less than 0.5, it is difficult to obtain the rust preventive effect, and usually 2.5 to 4.5.
Addition by weight% is sufficient and it is not necessary to add more than 5% by weight.

When the above self-emulsifying silicone antifoaming agent or the above rust preventive agent is added, the present invention I
The amount of water commensurate with the amount added is reduced, and in the present invention II, the amount of powder consisting of particles that dissolve in the amount of water commensurate with the amount added is reduced.

Next, a method for producing and using the dispersant for magnetic powder according to the present invention will be described. The method for producing a magnetic powder liquid dispersant according to the present invention I is not different from the conventional method, and a predetermined amount of water is added to a predetermined amount of a nonionic surfactant for control and a nonionic surfactant for control under stirring. It is a method in which a semi-transparent dispersion liquid or a transparent solution is added little by little, and if necessary, a predetermined amount of the above self-emulsifying silicone antifoaming agent or the above rust preventive agent is added.

In the method for producing the magnetic powder liquid dispersant according to the present invention II, a predetermined amount of each compounding component is put into a container (for example, a tank made of stainless steel) and thoroughly mixed using a stirrer (for example, an electric mixer). By doing so, a conventional nonionic surfactant and a controlling nonionic surfactant on each particle surface of the powder used, and a predetermined amount of the self-emulsifying silicone defoaming agent and the rust preventive agent added as necessary. It is a method of absorbing or adsorbing. Even when the defoaming agent or the rust preventive agent is added, the resulting magnetic powder liquid dispersant (powder) has sufficient fluidity as long as the respective addition amounts do not exceed the above-mentioned upper limits. ing.

The method of using the magnetic powder liquid dispersant according to the present invention I is not different from that of the magnetic powder liquid dispersant described above, and a required amount is added to water to prepare the magnetic powder liquid.

The method of using the magnetic powder liquid dispersant according to the present invention II is also to prepare a magnetic powder liquid by adding a required amount to water in the same manner as described above. Specifically, for example, per 1 liter of water. When preparing a magnetic powder liquid in which 0.2 to 2 g of fluorescent magnetic powder is dispersed, the concentration of the active ingredient (components other than powder consisting of water-soluble particles: nonionic surfactant, etc.) per liter of water is usually If an amount of 1 to 3% is added, mixed and stirred, the powder will be rapidly dissolved, and a magnetic powder liquid that is no different from the case of using a conventional magnetic powder liquid dispersant can be prepared.

[0033]

The operation of the present invention having the above-described structure will be described below. First, in the present invention, the control of the defoaming persistence (control of the foaming suppression time of the prepared magnetic powder solution) can be performed according to the compounding ratio of the commonly used nonionic surfactant and the controlling nonionic surfactant. This is due to the presence and amount of nonionic surfactant for control. When the control nonionic surfactant is added to the conventional nonionic surfactant of the present invention, the defoaming persistence becomes longer in proportion to the amount thereof (the foaming suppression time of the prepared magnetic powder liquid becomes longer) and the prepared magnetic powder. Although the wettability of the liquid becomes worse, the wettability of the prepared magnetic powder liquid is not so bad as compared with the extent that the defoaming persistence becomes longer, and the dispersibility is not affected theoretically about a unique phenomenon. Unfortunately, the elucidation has not been done yet. However, it can be guaranteed by the examples described later that this phenomenon occurs with repetitive continuity.

Next, the volume (volume) and the weight of the magnetic powder liquid dispersant according to the present invention II are much smaller and lighter than those of the conventional magnetic powder liquid dispersant. This is because the dispersant uses "water" as a medium of an active ingredient (nonionic surfactant or the like), while "powder" serves as a medium of an active ingredient (same as above). It will be as follows if the numerical values are shown and explained. In the case of using 60 l of the magnetic powder liquid, when using a conventional magnetic powder liquid dispersant (for example, Super Magna magnetic powder dispersant BC-600: specific gravity 1.04: trade name, manufactured by Marktec Co., Ltd.), Usually 1.
It is necessary to add 2 liters (volume 1200 cm ³ : weight 1248 g), but as shown in Example 8 below, when the powdery dispersant according to the present invention is used, 120 g (for example, in Example 8 below) is used. Since the apparent specific gravity of the powdery dispersant is 0.60, the volume of 120 g of the powdery dispersant is about 200 cm ³
Is added).

When the powdery dispersant according to the present invention II is added to water, the nonionic surfactants of HLB 8 to 14 (common nonionic surfactants and control nonionic surfactants) are dissolved in water. Until each particle dissolves in water because it is absorbed or adsorbed in a single particle, it is in a separated state for each particle, and a very small amount is added to a large amount of water. Therefore, microscopically, even if the milky white dispersion liquefaction phenomenon or jelly-like phenomenon occurs,
Since these phenomena are instantaneously passed through, the viscosity of the entire system does not rise, and a magnetic powder liquid is obtained which is no different from the case of using the conventional magnetic powder liquid dispersant. The mixed water-soluble particles do not adversely affect the flaw detection result and the like because they dissolve in water.

[0036]

EXAMPLES The present invention will be described more specifically below with reference to examples and comparative examples.

Example 1 <Prescription> A. Tap water: 90.9% by weight (200 parts by weight) Sodium nitrite: 4.5% by weight (10 parts by weight) Neugen ET115 (trade name: Daiichi Kogyo Seiyaku Co., Ltd.)
0.5% by weight (1 part by weight) Epan 410 (trade name: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
4.1% by weight (9 parts by weight) B.I. Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Neugen ET115 (above): 0.92% by weight (2 parts by weight) Epan 410 (above): 3.68 Wt% (8 parts by weight) C.I. Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Neugen ET115 (above): 2.3% by weight (5 parts by weight) Epan 410 (above): 2.3 Wt% (5 parts by weight) D. Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Neugen ET115 (above): 3.68% by weight (8 parts by weight) Epan 410 (above): 0.92 Wt% (2 parts by weight) E. Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Neugen ET115 (above): 4.1% by weight (9 parts by weight) Epan 410 (above): 0.5 % (1 part by weight) <Manufacturing method> Tap water is gradually added to Neugen ET115 and Epan 410 with stirring to mix / dissolve, and further sodium nitrite is added to mix / dissolve with stirring to mix A to E. 220 parts by weight of a liquid dispersant for each magnetic powder liquid (specific gravity 1.00) was obtained.

<Performance test> (1) Wettability test 20 ml of each of the liquid dispersants for magnetic powder liquids A to E obtained above was added to 1 l of water, and the wettability of each aqueous solution prepared was mirror-finished stainless steel polishing plate. The surface tension of each aqueous solution was measured by using a Dunui surface tension meter, while visually observing using the. Table 1 shows the results.

(2) Defoaming persistence test and scum generation test 1200 ml of the liquid dispersant for magnetic powder liquids A to E obtained here
Was prepared by adding 60 ml of water to each of the aqueous solutions prepared above and 1200 ml of Super Magna magnetic powder dispersant BC-600 (trade name: manufactured by Marktec Co., Ltd.) to 60 l of water to prepare a comparative aqueous solution. The defoaming duration was measured by the method, and the scum generation was visually observed. Table 1 shows the results. SUS304 shown in FIG.
60 liters of the above aqueous solution was placed in the tank 1 (volume 90 liters),
With the liquid temperature kept at 35 ° C, operate the pump 2
The aqueous solution is circulated through the pipe 3 as shown by the arrow in the figure, spraying from the shower 4, collection, and spraying are repeated, and the time from the start of circulation until the bubbles overflow from the upper surface of the tank 1 is measured. Also, 48 hours after the start of circulation, the pump 2 is stopped to stop the circulation. At this time, the state of adhesion of scum (oil-like silicone, etc.) to the tank wall surface and scum (oil-like silicone, etc.) on the liquid surface of the aqueous solution Observe the floating state.

(3) Dispersibility test 20 ml of each of the liquid dispersants for magnetic powder solutions A to E obtained above was added to 1 l of water, and each solution was added to Super Magna fluorescent magnetic powder LY-4700 (trade name: Marktec stock). Company
0.5 g) was added to prepare each magnetic powder solution. For comparison, Super Magna Magnetic Powder Dispersant BC-600 (supra) 2
A magnetic powder solution for comparison was prepared by adding 0.5 g of the above fluorescent magnetic powder to an aqueous solution prepared by adding 0 ml of water to 1 l of water. When the magnetic powder solutions after preparation and the comparative magnetic powder solutions were visually observed, the dispersion states in the magnetic powder solutions were all the same.

(4) Flaw detection test A square type billet made of steel was pasted with a JIS standard A-type standard test piece (circular Al-15 / 100) as an inspected object, which was magnetized by an axial electrification method according to a conventional method. After spraying each magnetic powder solution (including the comparative magnetic powder solution) used in the dispersibility test on one surface of the test piece, it was visually observed by irradiating it with an ultraviolet lamp in a dark place. As a result, even if any of the magnetic powder solutions was sprayed, the same clear defect indicating pattern could be confirmed.

(5) Redispersion test 50l of water was put in the tank 1 (volume 90l) made of SUS304 shown in Fig. 2 and the pump 2 was operated with the liquid temperature kept at 35 ° C, as shown by the arrow in the figure. Water is circulated through the pipe 3 and 1000 ml of the liquid dispersant for magnetic powder liquid A obtained here and 50 g of Super Magna fluorescent magnetic powder LY-4700 (described above) are added to the water in the circulation, After circulating for 24 hours, take 1 liter and place in a beaker.
It was left for 72 hours in a ° C dryer. Although the magnetic powder had settled at the bottom of the beaker taken out from the dryer, the magnetic powder was dispersed again when lightly stirred. As a result of performing the same test as above on each of the liquid dispersants for magnetic powder liquids B to E obtained here, it was confirmed that the magnetic powder was dispersed again in all cases.

[0043]

[Table 1]

Comparative Example 1 <Prescription> Tap water: 90.9% by weight (200 parts by weight) Sodium nitrite: 4.5% by weight (10 parts by weight) Neugen ET115 (supra): 4.6% by weight (10 parts by weight) (Parts by weight) <Manufacturing method> Tap water is gradually added to Neugen ET115 with stirring to mix / dissolve, and sodium nitrite is added to stirring with mixing / dissolving liquid dispersant 220
Parts by weight were obtained. <Performance test> The results of the wettability test, the defoaming persistence test and the scum generation test performed in the same manner as in Example 1 were "wet", "surface tension: 30 dyne / cm ² " and "foaming duration. : 0.25 hr "and" no occurrence ". The results of the dispersibility test, flaw detection test, and redispersibility test conducted in the same manner as in Example 1 were all the same as those of the liquid dispersants for magnetic powder liquids of Examples A to E.

Comparative Example 2 <Prescription> Tap water: 90.9% by weight (200 parts by weight) Sodium nitrite: 4.5% by weight (10 parts by weight) Epan 410 (supra): 4.6% by weight (10 parts by weight) (Parts by weight) <Manufacturing method> Tap water was gradually added to Epan 410 under stirring to mix / dissolve, and sodium nitrite was added under stirring to mix / dissolve to obtain 220 parts by weight of a liquid dispersant. <Performance Test> The results of the wettability test, the defoaming persistence test and the scum generating test performed in the same manner as in Example 1 were “repellency”, “surface tension: 41 dyne / cm ² ”, and “defoaming duration”. : 24 hours ”and“ no occurrence ”. In addition, Example 1
As a result of conducting a dispersibility test in the same manner as above, it was confirmed that the magnetic powder aggregated and floated on the liquid surface during the preparation of the magnetic powder liquid, and therefore it cannot be used as a dispersant for the magnetic powder liquid.

Example 2 <Prescription> A '. Tap water: 88.6% by weight (200 parts by weight) Sodium nitrite: 4.4% by weight (10 parts by weight) Neugen ET115 (supra): 0.4% by weight (1 part by weight) Epan 410 (previously described) … 4.0% by weight (9 parts by weight) Self-emulsifying type silicone defoamer XS64-A9512 (trade name: manufactured by Toshiba Silicone Co., Ltd.)… 2.6% by weight (6
Parts by weight) B '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Neugen ET115 (supra): 0.88% by weight (2 parts by weight) Epan 410 (supra): 3.52 % By weight (8 parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (supra) ... 2.6% by weight (same as above) C '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Neugen ET115 (supra): 2.2% by weight (5 parts by weight) Epan 410 (supra): 2.2 % By weight (5 parts by weight) Self-emulsifying type silicone defoaming agent XS64-A9512 (supra) ... 2.6% by weight (same as above) D '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Neugen ET115 (above): 3.52% by weight (8 parts by weight) Epan 410 (above): 0.88 % By weight (2 parts by weight) Self-emulsifying silicon defoaming agent XS64-A9512 (supra) ... 2.6% by weight (same as above) E '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Neugen ET115 (above): 4.0% by weight (9 parts by weight) Epan 410 (above): 0.4 % By weight (1 part by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (supra) ... 2.6% by weight (same as above) <Manufacturing method> Tap water is gradually added to Neugen ET115 and Epan 410 under stirring and mixed.・ Soluble and further sodium nitrite and self-emulsifying silicon defoamer XS64
-Add A9512 under stirring, mix and dissolve,
226 parts by weight of each of the liquid dispersants A'to E'for magnetic powder liquids (specific gravity 1.05) were obtained.

<Performance test> With respect to each of the liquid dispersants A'to E'for magnetic powder liquid obtained here, the wettability test, the defoaming persistence test and the scum generation test were conducted in the same manner as in Example 1. The results are shown in Table 2. The results of the dispersibility test, the flaw detection test, and the redispersibility test performed in the same manner as in Example 1 are all the same as those of the liquid dispersants for magnetic powder solutions of A ′ to E ′ of Example 1. It was

[0048]

[Table 2]

Comparative Example 3 <Prescription> Tap water: 88.6% by weight (200 parts by weight) Sodium nitrite: 4.4% by weight (10 parts by weight) Neugen ET115 (described above): 4.4% by weight (10 parts by weight) (Parts by weight) Self-emulsifying type silicone defoaming agent XS64-A9512 (described above) ... 2.6% by weight (6 parts by weight) <Manufacturing method> Tap water is gradually added to Neugen ET115 with stirring to mix and dissolve it. Sodium nitrite and a self-emulsifying silicon defoaming agent XS64-A9512 were added under stirring, mixed and dissolved to obtain 226 parts by weight of a liquid dispersant (specific gravity 1.05). <Performance test> The results of the wettability test, the defoaming persistence test and the scum generation test performed in the same manner as in Example 1 were "wet", "surface tension: 30 dyne / cm ² " and "foaming duration. : 0.5 hr ”and“ very small amount floating on the liquid surface ”. Further, the results of the dispersibility test, the flaw detection test, and the redispersibility test performed in the same manner as in Example 1 are all A to A in Example 1.
It was equivalent to the liquid dispersant for magnetic powder liquid of E.

Comparative Example 4 <Prescription> Tap water: 88.6% by weight (200 parts by weight) Sodium nitrite: 4.4% by weight (10 parts by weight) Epan 410 (supra): 4.4% by weight (10 parts by weight) (Parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (previous) ... 2.6% by weight (6 parts by weight) <Production method> Tap water is gradually added to Epan 410 under stirring to mix and dissolve, and further. Sodium nitrite and a self-emulsifying silicon defoaming agent XS64-A9512 were added under stirring, mixed and dissolved to obtain 226 parts by weight of a liquid dispersant (specific gravity 1.05). <Performance test> The results of the wettability test, the defoaming persistence test and the scum generation test performed in the same manner as in Example 1 were "vigorous repellency", "surface tension: 42 dyne / cm ² " and "foaming persistence. It was "time: 48 hours" and "floating on the liquid surface in a very small amount". Further, as a result of a dispersibility test carried out in the same manner as in Example 1, it was confirmed that the magnetic powder aggregated during the preparation of the magnetic powder liquid and floated on the liquid surface, and could not be used as a dispersant for the magnetic powder liquid.

Example 3 <Prescription> F. Tap water: 90.9% by weight (200 parts by weight) Sodium nitrite: 4.5% by weight (10 parts by weight) Newcol 405 (trade name: Nippon Emulsifier Co., Ltd.)
Made) ... 0.5% by weight (1 part by weight) Epan 410 (previously mentioned) ... 4.1% by weight (9 parts by weight) G. Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Newcol 405 (above): 0.92% by weight (2 parts by weight) Epan 410 (above): 3. 68% by weight (8 parts by weight) Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Newcol 405 (above): 2.3% by weight (5 parts by weight) Epan 410 (above): 2. 3% by weight (5 parts by weight) I. Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Newcol 405 (supra): 3.68% by weight (8 parts by weight) Epan 410 (supra): 0. 92% by weight (2 parts by weight) J. Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Newcol 405 (above): 4.1% by weight (9 parts by weight) Epan 410 (above): 0. 5% by weight (1 part by weight) <Production method> 220 parts by weight of the liquid dispersant for each magnetic powder liquid of F to J (specific gravity is the same as in the production method of Example 1 except that Neugen ET115 is replaced with Newcol 405). 1.00)
I got

<Performance Test> Table 3 shows the results of the wettability test and the defoaming persistence test conducted in the same manner as in Example 1 for the liquid dispersants for magnetic powder liquids F to J obtained here. . Further, the results of the dispersibility test, the flaw detection test, and the redispersibility test performed in the same manner as in Example 1 are all A to A in Example 1.
It was equivalent to the liquid dispersant for magnetic powder liquid of E.

[0053]

[Table 3]

Example 4 <Prescription> F '. Tap water: 88.6% by weight (200 parts by weight) Sodium nitrite: 4.4% by weight (10 parts by weight) Newcol 405 (supra): 0.4% by weight (1 part by weight) Epan 410 (previously described) ) ... 4.0% by weight (9 parts by weight) Self-emulsifying type silicone defoaming agent XS64-A9512 (previously) ... 2.6% by weight (6 parts by weight) G '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Newcol 405 (above): 0.88% by weight (2 parts by weight) Epan 410 (above): 3. 52% by weight (8 parts by weight) Self-emulsifying silicon defoaming agent XS64-A9512 (supra) ... 2.6% by weight (same as above) H '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Newcol 405 (above): 2.2% by weight (5 parts by weight) Epan 410 (above): 2. 2% by weight (5 parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (supra) ... 2.6% by weight (same as above) I '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Newcol 405 (above): 3.52% by weight (8 parts by weight) Epan 410 (above): 0. 88% by weight (2 parts by weight) Self-emulsifying silicon defoaming agent XS64-A9512 (supra) ... 2.6% by weight (same as above) J '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Newcol 405 (above): 4.0% by weight (9 parts by weight) Epan 410 (above): 0. 4% by weight (1 part by weight) Self-emulsifying type silicon defoaming agent XS64-A9512 (supra) ... 2.6% by weight (same as above) <Production method> Production method of Example 2 except that Neugen ET115 was replaced with Newcol 405. 226 parts by weight of each of the liquid dispersants F'to J'for magnetic powder liquids (specific gravity 1.0
5) was obtained.

<Performance Test> The results of the wettability test and the defoaming persistence test performed in the same manner as in Example 1 for the liquid dispersants F'to J'for magnetic powder liquid obtained here are shown in Table 4. Shown in. The results of the dispersibility test, the flaw detection test, and the redispersibility test performed in the same manner as in Example 1 are all the same as Example 1.
It was equivalent to the liquid dispersant for magnetic powder liquids of A to E.

[0056]

[Table 4]

Example 5 <Prescription> K. Tap water: 90.9% by weight (200 parts by weight) Sodium nitrite: 4.5% by weight (10 parts by weight) Sorgen TW60 (trade name: Daiichi Kogyo Seiyaku Co., Ltd.)
Made) ... 0.5% by weight (1 part by weight) Epan 410 (previously mentioned) ... 4.1% by weight (9 parts by weight) L. Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Sorgen TW60 (above): 0.92% by weight (2 parts by weight) Epan 410 (above): 3.68 Wt% (8 parts by weight) M.I. Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Sorgen TW60 (above): 2.3% by weight (5 parts by weight) Epan 410 (above): 2.3 % By weight (5 parts by weight) Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Sorgen TW60 (above): 3.68% by weight (8 parts by weight) Epan 410 (above): 0.92 Wt% (2 parts by weight) O. Tap water: 90.9% by weight (same as above) Sodium nitrite: 4.5% by weight (same as above) Sorgen TW60 (above): 4.1% by weight (9 parts by weight) Epan 410 (above): 0.5 % By weight (1 part by weight) <Production method> 220 parts by weight of the liquid dispersant for each magnetic powder liquid of K to O (both specific gravities: 1.0%) in the same manner as in the production method of Example 1 except that Neugen ET115 was replaced with Solgen TW60. 00) was obtained.

<Performance Test> Table 4 shows the results of the wettability test and the defoaming persistence test conducted in the same manner as in Example 1 for the liquid dispersants for magnetic powder liquids K to O obtained here. . Further, the results of the dispersibility test, the flaw detection test, and the redispersibility test performed in the same manner as in Example 1 are all A to A in Example 1.
It was equivalent to the liquid dispersant for magnetic powder liquid of E.

[0059]

[Table 5]

Example 6 <Prescription> K '. Tap water: 88.6% by weight (200 parts by weight) Sodium nitrite: 4.4% by weight (10 parts by weight) Sorgen TW60 (supra): 0.4% by weight (1 part by weight) Epan 410 (supra) ... 4.0% by weight (9 parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (described above) ... 2.6% by weight (6 parts by weight) L '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Sorgen TW60 (above): 0.88% by weight (2 parts by weight) Epan 410 (above): 3.52 % By weight (8 parts by weight) Self-emulsifying type silicone defoaming agent XS64-A9512 (supra) ... 2.6% by weight (same as above) M '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Sorgen TW60 (above): 2.2% by weight (5 parts by weight) Epan 410 (above): 2.2 % By weight (5 parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (supra) ... 2.6% by weight (same as above) N '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Sorgen TW60 (above): 3.52% by weight (8 parts by weight) Epan 410 (above): 0.88 % By weight (2 parts by weight) Self-emulsifying silicon defoamer XS64-A9512 (supra) ... 2.6% by weight (same as above) O '. Tap water: 88.6% by weight (same as above) Sodium nitrite: 4.4% by weight (same as above) Sorgen TW60 (above): 4.0% by weight (9 parts by weight) Epan 410 (above): 0.4 % By weight (1 part by weight) Self-emulsifying type silicone defoaming agent XS64-A9512 (supra) ... 2.6% by weight (same as above) <Manufacturing method> The same as the manufacturing method of Example 2 except that Neugen ET115 is replaced with Solgen TW60. 226 parts by weight of liquid dispersant for each magnetic powder liquid of K'to O '(specific gravity 1.05)
I got

<Performance Test> The results of the wettability test and the defoaming persistence test, which were carried out in the same manner as in Example 1, were carried out for each of the liquid dispersants for magnetic powder liquid of K ′ to O ′ obtained here. Shown in. The results of the dispersibility test, the flaw detection test, and the redispersibility test performed in the same manner as in Example 1 are all the same as Example 1.
It was equivalent to the liquid dispersant for magnetic powder liquids of A to E.

[0062]

[Table 6]

Example 7 <Prescription> P.P. Sodium tripolyphosphate powder ... 81.8% by weight
(90 parts by weight) Sodium molybdate powder ... 9.1% by weight (10 parts by weight) Nucor 864 (trade name: Nippon Emulsifier Co., Ltd.)
Made) ... 0.9 wt% (1 part by weight) Pluronic L-44 (trade name: Asahi Denka Kogyo Co., Ltd.
Made) ... 8.2% by weight (9 parts by weight) Q. Sodium tripolyphosphate powder ... 81.8% by weight
(Same as above) Sodium molybdate powder ... 9.1 wt% (Same as above) Newcol 864 (supra) ... 1.82 wt% (2 parts by weight) Pluronic L-44 (supra) ... 7.28 wt% (8 Parts by weight) Sodium tripolyphosphate powder ... 81.8% by weight
(Same as above) Sodium molybdate powder ... 9.1 wt% (Same as above) Newcol 864 (previous) ... 4.55 wt% (5 parts by weight) Pluronic L-44 (previous) ... 4.55 wt% (5 Parts by weight) Sodium tripolyphosphate powder ... 81.8% by weight
(Same as above) Sodium molybdate powder ... 9.1 wt% (Same as above) Newcol 864 (supra) ... 7.28 wt% (8 parts by weight) Pluronic L-44 (supra) ... 1.82 wt% (2 Parts by weight) Sodium tripolyphosphate powder ... 81.8% by weight
(Same as above) Sodium molybdate powder ... 9.1% by weight (Same as above) Newcor 864 (previously mentioned) ... 8.2% by weight (9 parts by weight) Pluronic L-44 (previously mentioned) ... 0.9% by weight (1) (Parts by weight) <Manufacturing method> Sodium tripolyphosphate powder and sodium molybdate powder are mixed, Newcol 864 and Pluronic L-44 are added to this mixture, and the mixture is thoroughly mixed and stirred, and powder for each magnetic powder liquid of P to T is added. 110 parts by weight of a particulate dispersant (both having an apparent specific gravity of 0.56) were obtained.

<Performance test> A wettability test was conducted in the same manner as in Example 1 except that 2 g of the powdery dispersant for magnetic powder liquids P to T obtained here was added to 1 l of water to prepare respective aqueous solutions. I went. Table 6 shows the results. The defoaming persistence test and the scum generation test were conducted in the same manner as in Example 1 except that 120 g of each of the powdery dispersants P to T obtained here for magnetic powder liquid was added to 60 l of water to prepare each aqueous solution. And went. Table 6 shows the results. The dispersibility was the same as in Example 1 except that 2 g of the powdery dispersant for magnetic powder liquids P to T obtained here was added to 1 l of water and dissolved to prepare a magnetic powder liquid. As a result of the test and the flaw detection test, it was confirmed that the liquid dispersant for magnetic powder liquids of A to E of Example 1 had the same performance. 100 g of the powdery dispersant for each magnetic powder liquid of P to T obtained here and Super Magna fluorescent magnetic powder LY-47
00 50 g was mixed and put into circulating water,
As a result of a redispersibility test conducted in the same manner as in Example 1, it was confirmed that the liquid dispersant for magnetic powder liquids A to E in Example 1 had equivalent performance.

[0065]

[Table 7]

Comparative Example 5 <Formulation> Sodium tripolyphosphate powder ... 81.8% by weight (90
Parts by weight) Sodium molybdate powder ... 9.1% by weight (10 parts by weight) Newcol 864 (previous) ... 9.1% by weight (10 parts by weight) <Production Method> Sodium tripolyphosphate powder and sodium molybdate powder Mix and add Newcol 864 to this mixture, mix and stir well to prepare powdered dispersant 11
0 part by weight (apparent specific gravity 0.56) was obtained. <Performance Test> The results of the wettability test, the defoaming persistence test and the scum generating test performed in the same manner as in Example 7 were “wet”, “surface tension: 29 dyne / cm ² ”, and “defoaming duration time”. : 0.25 hr "and" no occurrence ". The results of the dispersibility test, the flaw detection test, and the redispersibility test performed in the same manner as in Example 7 were all the same as those of the powdery dispersants for magnetic powder solutions of P to T in Example 7. .

Comparative Example 6 <Prescription> Sodium tripolyphosphate powder: 81.8% by weight (90
Parts by weight) Sodium molybdate powder ... 9.1% by weight (10 parts by weight) Pluronic L-44 (previously) ... 9.1% by weight (10 parts by weight) <Production Method> Sodium tripolyphosphate powder and sodium molybdate powder Pluronic L-44 was added to this mixture, and the mixture was thoroughly mixed and stirred to prepare powdered dispersant 1
10 parts by weight (apparent specific gravity 0.56) was obtained. <Performance Test> The results of the wettability test, the defoaming persistence test and the scum generating test performed in the same manner as in Example 7 were “repellency”, “surface tension: 39 dyne / cm ² ”, and “defoaming duration time”. : 24 hours ”and“ no occurrence ”. In addition, Example 7
As a result of the dispersibility test performed in the same manner as above, it was confirmed that the magnetic powder aggregated during the preparation of the magnetic powder liquid and floated on the liquid surface, and thus it could not be used as a dispersant for the magnetic powder liquid.

Example 8 <Prescription> P '. Sodium tripolyphosphate powder ... 77.5% by weight
(90 parts by weight) Sodium molybdate powder ... 8.6% by weight (10 parts by weight) Newcol 864 (supra) ... 0.9% by weight (1 part by weight) Pluronic L-44 (supra) ... 7.8 % By weight (9 parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) Q '. Sodium tripolyphosphate powder ... 77.5% by weight
(Same as above) Sodium molybdate powder ... 8.6 wt% (Same as above) Newcol 864 (supra) ... 1.74 wt% (2 parts by weight) Pluronic L-44 (supra) ... 6.96 wt% (8 Parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) R '. Sodium tripolyphosphate powder ... 77.5% by weight
(Same as above) Sodium molybdate powder ... 8.6% by weight (Same as above) Newcor 864 (previously mentioned) ... 4.35% by weight (5 parts by weight) Pluronic L-44 (previously mentioned) ... 4.35% by weight (5) Parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) S '. Sodium tripolyphosphate powder ... 77.5% by weight
(Same as above) Sodium molybdate powder ... 8.6 wt% (Same as above) Newcol 864 (previous) ... 6.96 wt% (8 parts by weight) Pluronic L-44 (previous) ... 1.74 wt% (2 Parts by weight) Self-emulsifying type silicone defoaming agent XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) T '. Sodium tripolyphosphate powder ... 77.5% by weight
(Same as above) Sodium molybdate powder ... 8.6% by weight (Same as above) Newcol 864 (previous) ... 7.8% by weight (9 parts by weight) Pluronic L-44 (previous) ... 0.9% by weight (1) (Parts by weight) Self-emulsifying silicon antifoaming agent XS64-A9512 (previously) ... 5.2% by weight (6 parts by weight) <Production Method> Sodium tripolyphosphate powder and sodium molybdate powder are mixed, and Newcol is added to this mixture. 864, Pluronic L-44, and self-emulsifying silicon defoaming agent XS64-A9512, mixed well and stirred, and 116 parts by weight of powder dispersant for each magnetic powder liquid of P'to T '(apparent specific gravity 0.60) was obtained.

<Performance Test> With respect to each of the powdery dispersants P'to T'for magnetic powder liquid obtained here, the wettability test, the defoaming persistence test and the scum generation test were conducted in the same manner as in Example 7. The results are shown in Table 8. In addition, the results of the dispersibility test, flaw detection test and redispersibility test conducted in the same manner as in Example 7 are as follows.
All were equivalent to the liquid dispersants for magnetic powder liquids of A to E of Example 1.

[0070]

[Table 8]

Comparative Example 7 <Formulation> Sodium tripolyphosphate powder: 77.5% by weight (90
Parts by weight) Sodium molybdate powder ... 8.6% by weight (10 parts by weight) Newcol 864 (previously mentioned) ... 8.7% by weight (10 parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (previously described) 5.2% by weight (6 parts by weight) <Production method> Sodium tripolyphosphate powder and sodium molybdate powder are mixed, and Newcol 864 and a self-emulsifying silicon defoaming agent XS64-A95 are mixed in this mixture.
Add 12, and mix and stir well to prepare powdered dispersant 116
Parts by weight (apparent specific gravity 0.60) were obtained. <Performance Test> The results of the wettability test, the defoaming persistence test and the scum generating test performed in the same manner as in Example 7 were “wet”, “surface tension: 29 dyne / cm ² ”, and “defoaming duration time”. : 0.5 hr ”and“ very small amount floating on the liquid surface ”. The results of the dispersibility test, flaw detection test, and redispersibility test performed in the same manner as in Example 7 are all P ′ of Example 7.
It was equivalent to each of the powdery dispersants for magnetic powder liquids of ~ T '.

Comparative Example 8 <Formulation> Sodium tripolyphosphate powder: 77.5% by weight (90
Parts by weight) Sodium molybdate powder ... 8.6% by weight (10 parts by weight) Pluronic L-44 (previously mentioned) ... 8.7% by weight (10 parts by weight) Self-emulsifying silicon defoamer XS64-A9512 (previously described) ) ... 5.2% by weight (6 parts by weight) <Production method> Sodium tripolyphosphate powder and sodium molybdate powder are mixed, and Pluronic L-44 and the self-emulsifying silicon defoaming agent XS64-A9 are mixed in this mixture.
512, and mixed and stirred well to obtain powdered dispersant 11
6 parts by weight (apparent specific gravity 0.60) was obtained. <Performance Test> The results of the wettability test, the defoaming persistence test and the scum generating test performed in the same manner as in Example 7 were “repellency”, “surface tension: 39 dyne / cm ² ”, and “defoaming duration time”. : 48 hours "and" floating on the liquid surface in a very small amount ". Further, as a result of a dispersibility test carried out in the same manner as in Example 7, it was confirmed that the magnetic powder aggregated and floated on the liquid surface during the preparation of the magnetic powder liquid, and could not be used as a dispersant for the magnetic powder liquid.

Example 9 <Prescription> U. Glucose powder ... 81.8% by weight (90 parts by weight) Sodium nitrite powder ... 9.1% by weight (10 parts by weight) Sunmor N-60S (trade name: Nika Chemical Industry Co., Ltd.) ... 0.9% by weight % (1 part by weight) New Pole PE-64 (trade name: manufactured by Sanyo Chemical Industry Co., Ltd.) ... 8.2% by weight (9 parts by weight) V.I. Glucose powder: 81.8% by weight (same as above) Sodium nitrite powder: 9.1% by weight (same as above) Sunmor N-60S (previous): 1.82% by weight (2 parts by weight) NEWPOL PE-64 ( (Above) ... 7.28% by weight (8
Parts by weight) W. Glucose powder: 81.8% by weight (same as above) Sodium nitrite powder: 9.1% by weight (same as above) Sunmor N-60S (previous): 4.55% by weight (5 parts by weight) NEWPOL PE-64 ( (Above) ... 4.55% by weight (5
Parts by weight) X. Glucose powder: 81.8% by weight (same as above) Sodium nitrite powder: 9.1% by weight (same as above) Sunmor N-60S (previous): 7.28% by weight (8 parts by weight) NEWPOL PE-64 ( (Above) ... 1.82% by weight (2
Parts by weight) Y. Glucose powder: 81.8% by weight (same as above) Sodium nitrite powder: 9.1% by weight (same as above) Sunmor N-60S (previous): 8.2% by weight (9 parts by weight) NEWPOL PE-64 ( (Above) ... 0.9% by weight (1 part by weight) <Production method> Glucose powder and sodium nitrite powder are mixed, and Sunmol N-60S and Newpol PE-64 are added to this mixture, followed by thorough mixing and stirring. Then, 110 parts by weight of each U to Y magnetic powder liquid dispersant (apparent specific gravity 0.7
5) was obtained.

<Performance Test> With respect to each of the powdery dispersants U to Y obtained here, each of the wettability test, the defoaming persistence test and the scum generating test was conducted in the same manner as in Example 7. The results are shown in Table 9. The results of the dispersibility test, flaw detection test, and redispersibility test performed in the same manner as in Example 7 were all the same as those of the liquid dispersants for magnetic powder liquids of Examples A to E.

[0075]

[Table 9]

Comparative Example 9 <Prescription> Glucose powder: 81.8% by weight (90 parts by weight) Sodium nitrite powder: 9.1% by weight (10 parts by weight) Sunmor N-60S (above): 9.1 % By weight (10 parts by weight) <Production method> Glucose powder and sodium nitrite powder are mixed, and Sanmol N-60S is added to this mixture, and they are mixed and stirred well, and 110 parts by weight of powdered dispersant (apparent A specific gravity of 0.75) was obtained. <Performance Test> The results of the wettability test, the defoaming persistence test and the scum generating test performed in the same manner as in Example 7 were “wet”, “surface tension: 27 dyne / cm ² ”, and “defoaming duration time”. : 0.5 hr ”and“ no occurrence ”. The results of the dispersibility test, flaw detection test, and redispersibility test conducted in the same manner as in Example 7 were all the same as those of the powdery dispersants for magnetic powder liquids of U to Y in Example 9. .

Comparative Example 10 <Prescription> Glucose powder: 81.8% by weight (90 parts by weight) Sodium nitrite powder: 9.1% by weight (10 parts by weight) NEWPOL PE-64 (supra): 9.1 Weight% (10
(Parts by weight) <Production method> Glucose powder and sodium nitrite powder are mixed, and Newpol PE-64 is added to this mixture, and the mixture is well mixed and stirred to give 110 parts by weight of the powdered dispersant (apparent specific gravity 0.75. ) Got. <Performance Test> The results of the wettability test, the defoaming persistence test and the scum generating test performed in the same manner as in Example 7 were “repellency”, “surface tension: 39 dyne / cm ² ”, and “defoaming duration time”. : 24 hours ”and“ no occurrence ”. In addition, Example 7
As a result of the dispersibility test performed in the same manner as above, it was confirmed that the magnetic powder aggregated during the preparation of the magnetic powder liquid and floated on the liquid surface, and thus it could not be used as a dispersant for the magnetic powder liquid.

Example 10 <Prescription> U '. Glucose powder: 77.5 wt% (90 parts by weight) Sodium nitrite powder: 8.6 wt% (10 parts by weight) Sunmor N-60S (previous): 0.9 wt% (1 part by weight) New Pole PE-64 (supra) ... 7.8% by weight (9 parts by weight) Self-emulsifying silicone antifoam XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) V '. Glucose powder: 77.5% by weight (same as above) Sodium nitrite powder: 8.6% by weight (same as above) Sunmor N-60S (previous): 1.74% by weight (2 parts by weight) NEWPOL PE-64 ( (Above) ... 6.96% by weight (8
Parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) W '. Glucose powder ... 81.8% by weight (same as above) Sodium nitrite powder ... 9.1% by weight (same as above) Sunmor N-60S (previous) ... 4.35% by weight (5 parts by weight) NEWPOL PE-64 ( (Above) ... 4.35% by weight (5
Parts by weight) Self-emulsifying type silicone defoaming agent XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) X '. Glucose powder: 77.5% by weight (same as above) Sodium nitrite powder: 8.6% by weight (same as above) Sanmor N-60S (previous): 6.96% by weight (8 parts by weight) NEWPOL PE-64 ( (Above) ... 1.74% by weight (2
Parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) Y '. Glucose powder: 77.5% by weight (same as above) Sodium nitrite powder: 8.6% by weight (same as above) Sunmor N-60S (previous): 7.8% by weight (9 parts by weight) NEWPOL PE-64 ( Previous) 0.9% by weight (1 part by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (previous) ... 5.2% by weight (6 parts by weight) <Production method> Glucose powder and sodium nitrite powder And Sanmol N-60S, Newpol PE-64 and a self-emulsifying silicone defoamer XS64-A.
9512 was added, mixed well and stirred, and 116 parts by weight of the magnetic powder liquid dispersant U ′ to Y ′ (both having an apparent specific gravity of 0.7
8) was obtained.

<Performance Test> With respect to each of the powdery dispersants U'to Y'obtained here for the magnetic powder liquid, the wettability test, the defoaming persistence test and the scum generation test were conducted in the same manner as in Example 7. The results are shown in Table 10. The results of the dispersibility test, flaw detection test, and redispersibility test performed in the same manner as in Example 7 were all the same as those of the liquid dispersants for magnetic powder liquids of Examples A to E.

[0080]

[Table 10]

Comparative Example 11 <Prescription> Glucose powder: 77.5% by weight (90 parts by weight) Sodium nitrite powder: 8.6% by weight (10 parts by weight) Sunmor N-60S (previous): 8.7 % By weight (10 parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (previously) ... 5.2% by weight (6 parts by weight) <Production method> Glucose powder and sodium nitrite powder are mixed, and this mixture is added to this mixture. Sanmor N-60S and self-emulsifying silicon defoaming agent XS64-A9512 were added, mixed well and stirred to obtain 116 parts by weight of the powdered dispersant (apparent specific gravity:
78) was obtained. <Performance Test> The results of the wettability test, the defoaming persistence test and the scum generating test performed in the same manner as in Example 7 were “wet”, “surface tension: 28 dyne / cm ² ”, and “defoaming duration time”. : 0.5 hr ”and“ very small amount floating on the liquid surface ”. Further, the results of the dispersibility test, the flaw detection test, and the redispersibility test conducted in the same manner as in Example 7 are all the powders for magnetic powder solutions of U ′ to Y ′ of Example 10. It was the same as the dispersant.

Comparative Example 12 <Prescription> Glucose powder: 77.5% by weight (90 parts by weight) Sodium nitrite powder: 8.6% by weight (10 parts by weight) NEWPOL PE-64 (supra): 8.7 Weight% (10
(Parts by weight) Self-emulsifying silicone antifoaming agent XS64-A9512 (previously) ... 5.2% by weight (6 parts by weight) <Production method> Glucose powder and sodium nitrite powder are mixed, and Newpol PE- is added to this mixture. 64 and a self-emulsifying silicon antifoaming agent XS64-A9512 were added, and well mixed and stirred to obtain 116 parts by weight of a powdery dispersant (apparent specific gravity 0.78). <Performance Test> The results of the wettability test, the defoaming persistence test and the scum generating test performed in the same manner as in Example 7 were “repellency”, “surface tension: 39 dyne / cm ² ”, and “defoaming duration time”. : 48 hours "and" floating on the liquid surface in a very small amount ". Further, as a result of a dispersibility test carried out in the same manner as in Example 7, it was confirmed that the magnetic powder aggregated and floated on the liquid surface during the preparation of the magnetic powder liquid, and could not be used as a dispersant for the magnetic powder liquid.

Example 11 <Prescription> a. Sodium tripolyphosphate powder ... 81.8% by weight
(90 parts by weight) Sodium molybdate powder ... 9.1% by weight (10 parts by weight) Newcol 150 (trade name: Nippon Emulsifier Co., Ltd.)
Manufactured) ... 0.9 wt% (1 part by weight) Pluronic L-44 (supra) ... 8.2 wt% (9 parts by weight) b. Sodium tripolyphosphate powder ... 81.8% by weight
(Same as above) Sodium molybdate powder ... 9.1 wt% (Same as above) Newcol 150 (supra) ... 1.82 wt% (2 parts by weight) Pluronic L-44 (supra) ... 7.28 wt% (8 Parts by weight) c. Sodium tripolyphosphate powder ... 81.8% by weight
(Same as above) Sodium molybdate powder ... 9.1 wt% (Same as above) Newcol 150 (supra) ... 4.55 wt% (5 parts by weight) Pluronic L-44 (supra) ... 4.55 wt% (5 Parts by weight) d. Sodium tripolyphosphate powder ... 81.8% by weight
(Same as above) Sodium molybdate powder ... 9.1 wt% (Same as above) Newcol 150 (supra) ... 7.28 wt% (8 parts by weight) Pluronic L-44 (supra) ... 1.82 wt% (2 Parts by weight) e. Sodium tripolyphosphate powder ... 81.8% by weight
(Same as above) Sodium molybdate powder ... 9.1 wt% (Same as above) Newcol 150 (supra) ... 8.2 wt% (9 parts by weight) Pluronic L-44 (supra) ... 0.9 wt% (1 (Parts by weight) <Manufacturing method> 110 parts by weight of each magnetic powder dispersion agent a to e (apparent specific gravity 0.57) in the same manner as in the manufacturing method of Example 7 except that Newcol 864 is replaced with Newcol 150. )
I got

<Performance Test> With respect to each of the powdery dispersants for magnetic powder liquids a to e obtained here, the wettability test, the defoaming persistence test and the scum generation test were conducted in the same manner as in Example 7. The results are shown in Table 11. The results of the dispersibility test, flaw detection test, and redispersibility test performed in the same manner as in Example 7 were all the same as those of the liquid dispersants for magnetic powder liquids of Examples A to E.

[0085]

[Table 11]

Example 12 <Prescription> a '. Sodium tripolyphosphate powder ... 77.5% by weight
(90 parts by weight) Sodium molybdate powder ... 8.6% by weight (10 parts by weight) Newcol 150 (supra) ... 0.9% by weight (1 part by weight) Pluronic L-44 (supra) ... 7.8 % By weight (9 parts by weight) Self-emulsifying silicon defoaming agent XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) b '. Sodium tripolyphosphate powder ... 77.5% by weight
(Same as above) Sodium molybdate powder ... 8.6 wt% (Same as above) Newcol 150 (supra) ... 1.74 wt% (2 parts by weight) Pluronic L-44 (supra) ... 6.96 wt% (8 Parts by weight) Self-emulsifying type silicone defoaming agent XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) c '. Sodium tripolyphosphate powder ... 81.8% by weight
(Same as above) Sodium molybdate powder ... 9.1 wt% (Same as above) Newcol 150 (supra) ... 4.35 wt% (5 parts by weight) Pluronic L-44 (supra) ... 4.35 wt% (5 Parts by weight) Self-emulsifying type silicone defoaming agent XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) d '. Sodium tripolyphosphate powder ... 77.5% by weight
(Same as above) Sodium molybdate powder ... 8.6 wt% (Same as above) Newcol 150 (supra) ... 6.96 wt% (8 parts by weight) Pluronic L-44 (supra) ... 1.74 wt% (2 Parts by weight) Self-emulsifying type silicone defoaming agent XS64-A9512 (supra) ... 5.2% by weight (6 parts by weight) e '. Sodium tripolyphosphate powder ... 77.5% by weight
(Same as above) Sodium molybdate powder ... 8.6 wt% (Same as above) Newcol 150 (supra) ... 7.8 wt% (9 parts by weight) Pluronic L-44 (supra) ... 0.9 wt% (1 Parts by weight) Self-emulsifying silicon antifoaming agent XS64-A9512 (previous) ... 5.2% by weight (6 parts by weight) <Manufacturing method> The manufacturing method of Example 8 was used except that Newcol 864 was replaced with Newcol 150. Similarly, 116 parts by weight of each of the magnetic powder liquid dispersants a'to e '(both have an apparent specific gravity of 0.5).
9) was obtained.

<Performance Test> With respect to each of the powdery dispersants a ′ to e ′ for magnetic powder liquid obtained, the wettability test, the defoaming persistence test and the scum generation test were conducted in the same manner as in Example 7. Table 12 shows each of the results. The results of the dispersibility test, flaw detection test, and redispersibility test performed in the same manner as in Example 7 were all the same as those of the liquid dispersants for magnetic powder liquids of Examples A to E.

[0088]

[Table 12]

[0089]

According to the present invention, the defoaming durability is long (the foaming suppression time of the prepared magnetic powder liquid is long) and the magnetic powder liquid can be used practically in accordance with the demand of the site where the wet magnetic powder flaw detection test method is carried out. Or a dispersant for a magnetic powder liquid that has a relatively short defoaming persistence (the foaming suppression time of the prepared magnetic powder liquid is relatively short), but a magnetic powder liquid that has excellent wettability Can be provided. The former is suitable for a site where a steel material such as a square billet is an object to be inspected, and the latter is suitable for a site where a finished or semi-finished product such as a knuckle is an object to be inspected.

Further, according to the present invention, the defoaming durability is extremely long (the foaming suppression time of the prepared magnetic powder liquid is extremely long) and can be put to practical use, and further, the generation of scum during use is as small as possible. A magnetic powder liquid dispersant capable of preparing a liquid can be provided.

Furthermore, according to the present invention II, the volume and weight of the conventional magnetic powder liquid dispersant (liquid substance) is about 1/1.
It is possible to provide a powdery dispersant for a magnetic powder liquid, which has a volume and weight reduced to 0 and has the same performance as a conventional magnetic powder liquid dispersant.

Therefore, it can be said that the present invention greatly contributes to the steel industry and the automobile industry.

[Brief description of drawings]

FIG. 1 is a partial vertical cross-sectional explanatory view of a test device used for a defoaming persistence test and a scum generation test in the present invention.

FIG. 2 is a partial vertical cross-sectional explanatory view of a test apparatus used for the redispersibility test in the present invention.

[Explanation of symbols]

 1 tank 2 pump 3 pipe 4 shower

Front page continued (72) Inventor Kazuhiko Yamaoka 641 Funakura-cho, Yokosuka City, Kanagawa Mark Tech Co., Ltd., Kurihama Plant (72) Inventor Kazuhiko Ayuha 641, Funakura-cho, Yokosuka City, Kanagawa Mark Tech Co., Ltd., Kurihama Plant

Claims (3)

[Claims] 1. A dispersant for a magnetic powder used in a wet magnetic powder flaw detection test method, which comprises dissolving or dispersing 2 to 30% by weight of a nonionic surfactant of HLB 8 to 14 in 70 to 98% by weight of water. As a surfactant, polyoxyethylene alkyl ether type nonionic surfactant, polyoxyethylene alkylallyl ether type nonionic surfactant, polyoxyethylene alkyl ester type nonionic surfactant, polyoxyethylene alkylamine type nonion One or more nonionic surfactants selected from polyoxyethylene sorbitan fatty acid ester type nonionic surfactants and polyoxyethylene polyoxypropylene alkyl ether type nonionic surfactants in combination Defoaming persistence according to the blending ratio of both A dispersant for a magnetic powder used in a wet magnetic powder flaw detection test method characterized by being applied. 2. A powder 70 to 9 consisting of particles soluble in water.
8% by weight of HLB 8-14 nonionic surfactant 2-2
A dispersant for a magnetic powder liquid used in a wet magnetic powder flaw detection test method which absorbs or adsorbs 30% by weight, wherein the nonionic surfactant is a polyoxyethylene alkyl ether type nonionic surfactant, polyoxyethylene alkylallyl. 1 or 2 selected from ether type nonionic surfactants, polyoxyethylene alkyl ester type nonionic surfactants, polyoxyethylene alkylamine type nonionic surfactants and polyoxyethylene sorbitan fatty acid ester type nonionic surfactants Wet magnetic powder flaw detection, characterized in that the above nonionic surfactant and polyoxyethylene polyoxypropylene alkyl ether type nonionic surfactant are used in combination to impart defoaming persistence in accordance with the blending ratio of both. Dispersant for magnetic powder used in test method 3. A self-emulsifying silicone defoaming agent comprising polyoxyalkylene-modified silicone, 0.1 to 10% by weight.
A dispersant for a magnetic powder liquid used in the wet magnetic powder flaw detection test method according to claim 1 or 2, further comprising: