JP2018004273A - Strength measurement method and tension or compression test device for performing strength measurement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an efficient measurement method and measurement device in a tension or compression test device for conventionally performing measurement under a state where a test piece is subjected to thermal insulation at constant temperature.SOLUTION: In a strength measurement method by a tension or compression test device, using two sheets of surface heating bodies 3 that are composed of a surface heating unit in which heater elements are provided in a surface fashion and a magnet plate integrated on a rear surface of the surface heating unit and in which an electrode of an end of the surface heating unit is provided with a power source cord, measurement is performed in a state where a test piece is interleaved by the surface heating unit and a temperature controller connected with the power source cord keeps the test piece warm at constant temperature.SELECTED DRAWING: Figure 3

Description

The present invention relates to a strength measurement method for measuring a test piece while keeping a test piece at a constant temperature, and a tensile or compression test apparatus for measuring the strength.

In the measurement of strength in the tension or compression direction, when measuring the fracture of a test piece in a constant high-temperature atmosphere, a chamber system such as hot air blowing or the invention of Patent Document 1 is generally used. However, this method has many problems, such as an increase in the size of the apparatus, which requires a large amount of power, takes time to complete the measurement, and increases equipment costs. In particular, in the chamber system as disclosed in Patent Document 1, the entire test piece and the sensor must be kept warm, and it takes time to reach a certain temperature, which causes a problem in that the measurement efficiency is lowered.

JP 59-99330 A

Conventionally, in a tensile or compression test device that measures with a test piece held at a constant temperature, a large-sized device such as a chamber method has been used to keep the test piece warm. There were many problems such as that it took time to complete the measurement and the equipment cost was high.

As a result of intensive studies to solve the problems, the present inventors have found a technique related to the present invention and have completed the present invention.

The gist of the present invention will be described next. A first embodiment of the present invention, in a strength measurement method by a tensile or compression test, comprises a surface heating element provided with a heating element in a planar shape and a magnet plate integrated on the back side of the surface heating element, This is a strength measurement method in which a test piece is sandwiched using a surface heating element provided with a power cord at the end of the surface heating element, and the test piece is kept at a constant temperature by a temperature controller connected to the power cord. .

2nd embodiment of this invention is an intensity | strength measuring method as described in 1st embodiment whose said surface heating body is soft.

The third embodiment of the present invention is the strength measurement method according to any one of the first and second embodiments, wherein the test piece is a test piece for measuring tensile shear bond strength.

The fourth embodiment of the present invention is the strength measurement method according to any one of the first to third embodiments in which the test piece is sandwiched between two surface heating elements.

A fifth embodiment of the present invention comprises a surface heating element provided with a heating element in a planar shape, and a magnet plate integrated on the back side of the surface heating element, and an end electrode portion of the surface heating element Tensile or compression test in which a test piece is sandwiched using a surface heating element provided with a power cord, and the strength is measured with the temperature maintained at the constant temperature by setting a constant temperature with a temperature controller connected to the power cord Device.

A sixth embodiment of the present invention is the compression test apparatus according to the fifth embodiment, wherein the surface heating body is soft.

A seventh embodiment of the present invention is the compression test apparatus according to any of the fifth or sixth embodiments, wherein the test piece is a test piece for measuring tensile shear bond strength.

An eighth embodiment of the present invention is the compression test apparatus according to any one of the fifth to seventh embodiments in which the test piece is sandwiched using two surface heating elements.

With the strength measuring method and the strength measuring device of the present invention, only the test piece is kept warm, so that it is possible to measure efficiently without taking time to reach a certain temperature.

FIG. 1 is an example of a test piece, which is a test piece for measuring tensile shear bond strength. FIG. 2 is a side view of a test piece kept at a constant temperature by a surface heating element according to the method of the present invention. FIG. 3 is a top view of a test piece kept at a constant temperature by a surface heating element according to the method of the present invention. FIG. 4 shows the measurement results of the tensile shear bond strength at each set temperature by the three methods of Example 1, Comparative Example 1 and Comparative Example 2.

Details of the present invention will be described below. The surface heating element that can be used in the present invention is composed of a surface heating element and a magnet plate, and is integrated with a magnet plate that matches the size of the surface heating element. The bodies can be adsorbed by magnetic force. If the surface heating element is soft, it can be attached to the surface of a cylindrical body or a bent surface as well as the flat surface, and the surface heating element is preferably soft, specifically a silicone rubber heater, etc. However, it is not limited to this. In addition, the test piece described later may be sandwiched between one or more surface heating elements, but it is preferable to sandwich two or more sheets in order to keep stable heat.

The surface heating element that can be used in the present invention is formed of rubber or plastic in a state where the heating element is provided in a planar shape. In particular, the surface heating element is preferably formed of a soft material. The heating element refers to a wire, ribbon, strip, or the like made of nichrome 80/20 (80% nickel, 20% chromium). A power cord is provided on the end electrode part of the surface heating element. By turning on the power via the power cord, the temperature or temperature is controlled by the temperature controller, and the temperature is set by converting electricity into heat. .

The magnet plate that can be used in the present invention refers to a plate-like magnet formed by kneading magnetic powder or the like into rubber or plastic. In particular, a soft magnet plate is preferable.

Specific examples of the surface heating body include, but are not limited to, a silicone rubber heater manufactured by AS ONE Corporation.

Examples of the tensile or compression tester that can be used in the present invention include a universal testing machine manufactured by Orientec Co., Ltd.

The test piece that can be used in the present invention is prepared by bonding two adherends with an adhesive or the like, and is an adherend that can be used for measurement of tensile shear adhesive strength or peel adhesive strength. It refers to a cured product having a specific plate shape used for measurement of resin strength. By destroying the test piece, it is possible to measure adhesive strength, adhesive strength, strength, and the like. In the present invention, it is most preferable to use it for measuring the tensile shear bond strength.

Tensile or compression test equipment that can be used in the present invention is to fix both ends of the test piece with two metal chucks and break the test piece in the tensile or compressive direction, thereby increasing the adhesive strength and resin strength. It is a device that measures the intensity of. Specific examples of the tensile or compression test apparatus include a universal testing machine manufactured by Orientec Co., Ltd., but are not limited thereto.

A test piece as shown in FIG. 1 is sandwiched between two surface heating elements as shown in FIGS. At this time, the test piece is not affected by the magnetic force only because the two surface heating members are adsorbed by the magnetic force. Since the surface heating element generates heat and the test piece is kept at a constant temperature, measurement can be performed in a short time from the start of the heat holding.

EXAMPLES Next, although an Example is given and this invention is demonstrated further in detail, this invention is not limited only to an Example.

Example 1 is a method using the surface heating element of the present invention, and Comparative Examples 1 and 2 are conventional methods using a chamber that can be set to a specific temperature with hot air at normal pressure. The steps for measuring at each set temperature (unit: ° C.) are summarized in Table 1. The tensile shear bond strength described later is measured according to each condition. Here, the “temperature adjustment step” (unit: minute) indicates the time taken for the atmospheric temperature in the chamber to reach the set temperature. “Preheating step 1” (unit: minute) means that the sensor in the chamber is at the set temperature, but the metal chuck of the tensile tester is not at the set temperature, so the test piece is fixed. This is done before raising the temperature of the chuck itself to the set temperature. “Preliminary heating step 2” (unit: minute) is to keep the temperature at a set temperature after fixing the test piece with the chuck. The total time indicates the total time (unit: minutes) of the time taken in the “temperature adjustment step”, “preheating step 1”, and “preheating step 2”.

[Example 1]
In Example 1, a chamber is not used, and measurement is performed with a test piece sandwiched between two surface heating elements. Therefore, the “temperature adjustment step” and the “preheating step 1” are unnecessary. The test piece is fixed to the chuck of the tensile test apparatus, and the time until the set temperature is reached is confirmed by sandwiching the test piece between the two surface heating elements.

[Comparative Example 1]
In Comparative Example 1, measurement is performed using a chamber. Therefore, it is necessary to include a “temperature adjustment step” and a “preheating step 1”. In Comparative Example 1, after the test piece is fixed to the chuck, the “preheating step 2” is performed and the measurement is performed.

[Comparative Example 2]
In Comparative Example 2, measurement is performed using a chamber. Therefore, it is necessary to include a “temperature adjustment step” and a “preheating step 1”. In Comparative Example 2, the measurement is performed without the “preheating step 2” after the test piece is fixed to the chuck.

Tensile shear adhesive strength was measured for each set temperature of Example 1 and Comparative Examples 1 and 2 in Table 1. The results are shown in Table 2.

[Measurement of tensile shear bond strength]
Adhesive is applied to an adhesive area of 25 mm x 10 mm on one iron plate (SPCC-SD) of length 100 mm x width 25 mm x thickness 1.6 mm, and another iron plate is bonded and fixed with a fixture. Wipe off the protruding adhesive. As the adhesive, ThreeBond 2222P, which is an epoxy adhesive manufactured by ThreeBond Co., Ltd., was used. Thereafter, the adhesive is cured by heating in a hot air drying oven at 100 ° C. for 60 minutes to produce a test piece as shown in FIG. 1 (n = 5). The average value is calculated from the maximum strength (N) and the bonding area when the tensile speed is pulled at 10 mm / min in the state where the both ends of the test piece are fixed by the chuck of the universal testing machine and the process of Table 1 is performed. The “adhesive strength (MPa)” is measured from the value.

A diagram summarizing Table 2 is shown in FIG. Comparative Example 1 including “preheating step 2” and Example 1 of the present invention show tensile shear bond strengths close to each set temperature. On the other hand, in Comparative Example 2 in which the “preheating step 2” is not included, the tensile shear adhesive strength is higher than that in Comparative Example 1. Generally, when the set temperature is high, the storage elastic modulus tends to decrease because it approaches or exceeds the glass transition temperature. That is, when the set temperature is increased, the cured product tends to become soft. Therefore, Comparative Example 2 in which “Preheating Step 2” is not included has a high measured value of tensile shear adhesive strength in an atmosphere at 150 ° C., and is not correlated with Example 1 and Comparative Example 1. Moreover, although Example 1 and Comparative Example 1 have a correlation in tensile shear bond strength, the total time is greatly different as shown in Table 1, and Example 1 according to the present invention is an accurate measurement in a short time. Can be seen.

With the strength measurement method and the tensile or compression test apparatus for measuring the strength of the present invention, the measurement of the tension or compression method in which the test piece is kept warm at a constant temperature is accurately performed in a short time.

1: Adhered body 2: Adhesive 3: Surface heating body

Claims (8)

In a strength measurement method by a tensile or compression test, a surface heating element provided with a heating element in a planar shape and a magnet plate integrated on the back side of the surface heating element, and a power source is connected to an electrode at the end of the surface heating element A strength measurement method in which a test piece is sandwiched using a surface heating body provided with a cord, and the test piece is kept at a constant temperature by a temperature controller connected to the power cord. The strength measurement method according to claim 1, wherein the surface heating body is soft. The strength measurement method according to claim 1, wherein the test piece is a test piece for measuring tensile shear bond strength. The intensity | strength measuring method in any one of Claims 1-3 which pinches | interposes a test piece using two surface heating bodies. A surface heating element comprising a surface heating element provided with a heating element in a planar shape and a magnet plate integrated on the back side of the surface heating element, and using a surface heating element provided with a power cord at an end electrode portion of the surface heating element A tensile or compression testing device that sandwiches the test piece and measures the strength while the test piece is kept at a constant temperature with a temperature controller connected to the power cord. The compression test apparatus according to claim 5, wherein the surface heating body is soft. The compression test apparatus according to claim 5 or 6, wherein the test piece is a test piece for measuring tensile shear bond strength. The compression test apparatus according to any one of claims 5 to 7, wherein the test piece is sandwiched between two surface heating elements.