JPH0752184B2 - Contact medium for the detection end of ultrasonic measuring instruments - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The couplant of the present invention is used as a detection end of an ultrasonic measuring instrument used for measuring material thickness, detecting defects in tissue inside the material, and the like. It is interposed between the object and the object and is used for excellent detection amount transmission and protection of the detection end of the ultrasonic measuring instrument.

[Conventional technology]

Measurement of the plate thickness of the materials that make up various devices or piping,
Alternatively, an ultrasonic measuring instrument that utilizes the echo of ultrasonic waves in the inspection of internal defects such as defects scattered inside it has the advantage that it can be used even while the equipment or piping is in operation. Has been done.

However, glycerin, water, or oils such as motor oil are currently used as a contact medium for acoustically connecting the surface of the part to be inspected / measured and the tip of the probe of the measuring instrument. There is.

[Problems to be solved]

Depending on the contact medium of the above conventional products, there is almost no hindrance when the measured part is at or near room temperature, but when the temperature is higher than 60 ° C, evaporation of the contact medium, oxidative deterioration, charring, Burn-in occurs, which causes a measurement error, or makes inspection measurement impossible.

There are commercially available couplants for high temperature, but the results of using it in practice are that the rise and stability of ultrasonic echoes are poor, the adhesiveness is excessive, the workability is poor, and the bevel probe is used. When the child is slid on the surface of the portion to be measured, the contact medium cannot follow the movement of the probe, the thin film of the contact medium is interrupted and measurement becomes impossible, and the residue solidifies.
It is necessary to remove the residue of the contact medium adhering to the tip of the probe during measurement frequently by washing with water, etc., which makes continuous multi-point measurement difficult, and the deterioration at high temperatures is rapid. However, there was no satisfactory couplant as a contact medium for high temperature, such as the fact that it was limited to a short time.

The desired characteristics of the couplant are that the acoustic impedance is large, the acoustic transmission loss is small, and it is not likely to be adversely affected by the roughness of the surface of the subject. Being well-acquainted with the child, having good reverberation and sound stability, being easy to apply and wipe off the couplant, and being applied to the vertical surface or ceiling surface of the DUT Also in this case, there is no drooling, there is no adverse effect such as corrosion even if the contact medium remains on the surface of the object to be inspected, and the contactor slides smoothly and wear is reduced.

The present invention is intended to eliminate the above-mentioned drawbacks as much as possible and to provide a medium having desired characteristics.

[Means for solving problems]

The contact medium of the present invention is a lubricating base oil containing a urea compound as a gelling agent.

The lubricating base oil referred to in the present invention is usually a mineral oil, as long as the oil has a viscosity similar to that of the oil used as the lubricating oil.
Various oils can be used regardless of synthetic oil.

Examples of mineral oil include 70 pail, SAE10, SAE20, SAE3.
Various grades such as 0, SAE40, SAE50 and bright stock can be used.

Examples of synthetic oils include polybutene and poly α-
Olefin, alkylbenzene, alkylnaphthalene,
Diester, polyol ester, polyglycol, polyphenyl ether, allyl alkane, tricresyl phosphate, silicone oil, perfluoroalkyl ether and the like can be used.

Among these oils, a particularly preferred base oil has a viscosity range of 210
It is 2 to 40 cSt at ° F.

As the urea compound referred to in the present invention, a diurea compound,
Examples thereof include triurea compounds, tetraurea compounds, polyurea compounds, and urea-urethane compounds. Among these, diurea compounds represented by the following general formula are preferably used.

(In the formula, R _{1 to} R ₄ represent hydrogen or a monovalent hydrocarbon group, and R ₅ represents a divalent hydrocarbon group.) In the general formula of the diurea compound, R _{1 to} R ₄ are the same. May be different or different and each represents hydrogen or a monovalent hydrocarbon group.

Preferred are hydrogen, a cyclohexyl group, a cyclohexyl derivative group having 7 to 12 carbon atoms, or an alkyl group and alkenyl group having 8 to 20 carbon atoms.

Here, it is preferable that each of R ₁ and R ₂ , and R ₃ and R ₄ is not hydrogen.

Specific examples of the cyclohexyl group or the cyclohexyl derivative group having 7 to 12 carbon atoms include:
Cyclohexyl group, methylcyclohexyl group, dimethylcyclohexyl group, ethylcyclohexyl group, diethylcyclohexyl group, propylcyclohexyl group, isopropylcyclohexyl group, 1-methyl-3-propylcyclohexyl group, butylcyclohexyl group, amylcyclohexyl group, amyl-methylcyclohexyl group , A hexylcyclohexyl group, etc., and a particularly preferable one is a cyclohexyl group or a cyclohexyl derivative group having 7 to 8 carbon atoms, for example, a methylcyclohexyl group,
It is an ethylcyclohexyl group.

Further, as the alkyl group having 8 to 20 carbon atoms and the alkenyl group mentioned here, specifically, for example, an octyl group,
Nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, octadecynyl group, nonadecyl group, eicosyl group, octenyl group,
It has a linear structure such as a nonenyl group, a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl group, a nonadecenyl group, an eicosenyl group, or a side chain structure. Particularly preferred are alkyl groups having 16 to 19 carbon atoms, or alkenyl groups such as hexadecyl group, heptadecyl group, octadecyl group, octadecynyl group, nonadecyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadecenyl group.

Further, even if the carbon number is 20 or more, the object of the present invention can be sufficiently achieved, but there is a disadvantage in terms of raw material price.

Further, R ₅ in the above general formula preferably has 6 to 15 carbon atoms.
Is a divalent aromatic hydrocarbon group of, specifically, for example, Etc. are particularly preferably used, but other than that, if it is a divalent aromatic hydrocarbon group, one that exhibits excellent properties such as thermal stability and oxidation stability should be used. give.

The method for producing the urea compound used as the gelling agent for the raw material of the couplant of the present invention is arbitrarily selected, but the general formula X-N =
An isocyanate represented by C = O (where X represents a substituent), and a general formula Can be easily produced by reacting with a primary or secondary amine represented by

In this reaction, volatile solvents such as benzene, toluene, xylene, hexane, naphtha, diisobutyl ether, carbon tetrachloride, petroleum ether and the like can be used.

A lubricating base oil can also be used as a more applicable solvent.

These reactions are preferably performed within the range of 10 to 200 ° C.

During the reaction, the reactants need to be thoroughly mixed and stirred so that a homogeneous couplant is produced.

The gelling agent thus produced has the solvent removed if a volatile solvent is used during the reaction, and then
Lubricating base oil is added in an appropriate amount to become the couplant of the product.

When a lubricating base oil is used as a solvent during the reaction, it may be used as the contact medium of the product as it is after the reaction.

Additives may be added to the couplant of this invention to further improve its performance without damaging its properties.

For example, other gelling agents, extreme pressure agents, antioxidants, oiliness agents,
The performance of the contact medium can be further improved by adding a rust preventive agent, a viscosity index improver and the like.

In the contact medium of the present invention, the content of the gelling agent urea compound is preferably 2 to 25%, more preferably 3 to 20%, based on the total weight of the medium.

Next, examples will be shown.

Production Example 1 850 g of diphenylmethane-4,4'-diisocyanate 84 g
Of the above mineral oil (viscosity: 10.3 cSt at 210 ° F) and heated to 60 ° C to homogenously dissolve.

To this was added 67 g of cyclohexylamine that had been heated and melted, and a gelled substance was rapidly generated with vigorous stirring.

After heating for 30 minutes while continuing stirring to raise the temperature to 120 ° C., the mixture was passed through a roll mill to obtain an intended contact medium.

The content of the diurea compound represented by the following formula in this contact medium was 15 wt.%.

Production Example 2 159 g of 2,4-2,6-tolylene diisocyanate was added to 4,350 g of mineral oil (viscosity: 10.5 cSt at 210 ° F) and uniformly dissolved at room temperature.

To this was added octadecylamine (492 g) which had been melted by heating, and the mixture was vigorously stirred and a gel substance was rapidly formed.

After heating for 30 minutes while continuing stirring to raise the temperature to 100 ° C., the mixture was passed through a roll mill to obtain an intended couplant.

The content of the diurea compound represented by the following formula in this contact medium was 13 wt.%.

Production Example 3 182 g of vitrylene diisocyanate was added to 1,640 g of poly α-olefin oil (viscosity: 8.2 cSt at 210 ° F.), and the temperature was raised and the mixture was homogeneously dissolved at 70 ° C.

To this, 180 g of octylamine was added, and a gel-like substance was rapidly produced with vigorous stirring.

After heating for 30 minutes while continuing stirring to raise the temperature to 120 ° C., the mixture was passed through a roll mill to obtain an intended contact medium.

The content of the diurea compound represented by the following formula in this contact medium was 18 wt.%.

Example of use An ultrasonic type thickness meter DM-3 type manufactured by Krautkremer was used.

The measuring instrument was made of engineering plastic PEEK attached to the wedge part of the probe at the detection end.

At room temperature, measurement tests were performed using steel (S25C) test pieces having a thickness of 12 mm and 15 mm, respectively.

After heating these test pieces to 300 ° C in a muffle furnace,
The couplant was taken out of the furnace, and the couplant obtained in Production Example 1 was sequentially applied to a plurality of measurement points corresponding to the temperature drop of the test piece. The tentacles were applied continuously for 3 minutes. It should be noted that continuous application for 3 minutes is an extremely harsh use condition as compared with the normal probe application time.

Table 1 shows an example of the results of the measurement test.

All of the couplants tested were rapidly altered at the measurement points applied while the test piece was above 250 ° C, and the measured value display was within the range of about 3 to 12 seconds.

If the contact medium is applied while the test piece is in the range of 200 to 250 ° C, the oil film will be cut off by the crimping force of the probe, so the measured value display will be within the range of about 10 to 30 seconds. there were.

When the contact medium was applied when the test piece was in the range of 200 ° C or less, the oil film was not broken by the pressure force of the probe, and the measured value display was stable for about 30 to 50 seconds.

It was confirmed that the couplant according to the present invention functions sufficiently when the surface of the specimen is 200 ° C. or lower.

Effective time of contact medium Temperature ℃ Display time sec. Measuring instrument display value mm 300 3 15.5 289 11 15.6 276 12 15.7

Claims (4)

[Claims] 1. A contact medium for a detection end of an ultrasonic measuring instrument, characterized in that a lubricating base oil and a urea compound are main components. 2. A contact medium according to claim 1, wherein the lubricating base oil is a mineral oil and / or a synthetic oil. 3. The couplant according to claim 1, wherein the content of the urea compound is 2 to 25% based on the total weight of the couplant. 4. The contact medium according to claim 1, wherein the urea compound is a diurea compound.