JPH0363013B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a shear adhesion strength testing device.

(Prior Art) In recent years, the development of laminated materials such as vibration-damping steel plates or lightweight laminated steel plates in which a viscoelastic substance is interposed between two steel plates has progressed, and these materials are widely used in industries including automobiles.

Naturally, the quality of laminates with such a multilayer structure is determined by the adhesion strength of the connections between each layer, so when manufacturing or developing laminates,
From the standpoint of quality control or quality improvement research and research, measurement of the adhesion strength of the bonded portion is an indispensable and important matter.

There is no specific method for measuring the adhesion strength of such multilayered laminates, and JISK6850 (tensile shear adhesion strength test method), which is specified as a method for measuring the adhesive strength of adhesives, is used. Usually, JISK6854 (peel adhesion strength test method) is applied mutatis mutandis.

(Problems to be Solved by the Invention) By the way, as mentioned above, the above test method was established as a test method for the adhesive strength of adhesives, so there are several methods for testing laminates that have become products. There is a problem.

First, the problem with JISK6850 (tensile shear adhesion strength testing method) is that not only does it take a lot of effort and time to form a test piece, but the reproducibility (accuracy) of the obtained test values is not always sufficient. It is.

Figure 7 is a perspective view showing the shape of a test piece for tensile shear adhesion strength specified in JISK6850, in which 1 is the test piece, 2 is a steel plate, 3 is a viscoelastic material, 4 is a gripping part, and 5 is a This is the notch part. In the test, the grip portion 4 of the test piece is gripped and a tensile load is applied, the shear deformation resistance of the bonded portion and the amount of movement of the upper and lower steel plates are measured, and the shear adhesion strength is determined from this.

In order to form the test piece shown in the figure, a test piece 1 is cut out from a laminate, and a part thereof is cut out to form a notch 5. Note that b, l ₁ , l ₂ and l ₃ are each 25
±0.5mm, 38±1mm, 12.5±0.5mm and 100±0.5mm
It is. In order to form the above-mentioned notch 5, it is necessary to make a notch in the upper layer plate or the lower layer plate and the intermediate layer and remove a part of it, but this cut should not be too shallow or too deep; There are restrictions such as the cut must be perpendicular to the long axis and the corners of the cut must not be rounded. This is because if this condition is not met, an error will occur in the test value.

In order to form a test piece that satisfies the above conditions from a laminate, a high level of skill is required, and if there are a large number of test pieces, a large amount of time is required. Therefore, it is possible to mechanize the formation of test pieces, but this would require a large amount of equipment.

Furthermore, in a test device using the above test piece, a bending moment may be induced at the boundary between the bonded part and the notched part due to the stress balance between the two, and a peeling force may act on the bonded part. When this occurs, the apparent adhesive strength decreases, resulting in the essential problem that correct test values cannot be obtained.

In order to suppress the generation of this peeling force as much as possible, the JIS mentioned above stipulates that the test specimen thickness be as thick as possible, for example 1.6 mm for metal and 3.0 mm or more for plastic, but this thickness can be set arbitrarily for laminates. It cannot be selected and is usually thinner than the specified value above. For this reason, with thin laminates,
During the test, large bends occur and the resulting errors tend to occur.

Next, the JISK6854 peel adhesion strength testing method also has the disadvantage that not only the adhesive strength but also the bending deformation resistance of the test piece itself is added to the test value. For example, even if the adhesive strength itself is constant, if the thickness or strength of the test piece differs, the bending deformation resistance will change, and therefore the test value will also differ. In other words, this test method poses no problem in cases where the same test piece can be used at all times, such as in the case of adhesive tests, but it is inappropriate in cases where the test pieces have different configurations, such as in the case of laminates.

Note that JISK6852 also establishes a compression shear adhesion strength test method for adhesives, but the difficulty in forming test pieces is essentially the same as in the tensile adhesion test method described above.

As described above, the conventional test equipment for testing the shear adhesion strength of laminates has a number of problems.

The present invention was made in order to solve the problems in conventional testing methods and devices, especially testing devices, and aims to provide a shear adhesion strength testing device that requires less time and labor and has high testing accuracy. It is something.

(Means for solving the problem) In order to achieve the above object, the test device for determining the shear adhesion strength according to the present invention determines the shear adhesion strength of a laminate having a multilayer structure of three or more layers. In the test, a predetermined load was applied perpendicularly to the upper and lower surfaces of the test piece formed into a rectangular shape from the above-mentioned laminate, and the bonding surface and Loads are applied in parallel and in opposite directions to the upper and lower layers to generate shear deformation in the bonded area, and the maximum load at this time is divided by the area of the bonded area to determine the shear adhesion strength of the bonded area.

That is, the test device according to the present invention includes a fixed pedestal having a step formed on the upper surface and on which a test piece is placed;
a pull-out bar located above the fixed pedestal with the test piece in between and having a step formed on the lower surface in the opposite direction to the step of the fixed pedestal; means for applying a predetermined load to the upper and lower surfaces of the test piece in a direction perpendicular to the surface; ; means for restricting the upward movement of the pull-out bar and moving it in the horizontal direction; and a measuring device for measuring the amount of movement of the pull-out bar and the pull-out load. In addition, in the steps formed on the fixed pedestal and the pull-out bar, the upright portions were inclined inward by 5 to 10 degrees, and grooves were formed at the corners of the steps.

There are two types of measuring instruments in this test device: one to measure the amount of movement of the pull-out bar and one to measure the pull-out load. Of these, the measuring device for the pull-out load is the purpose of use of this test device. It measures shear adhesion strength, and is inseparably included in conventional test equipment. However, the measuring device used to measure the amount of movement of the pull-out bar is used to measure the amount of shear deformation applied to the layer being tested, and is used to measure the amount of shear deformation and strength from the start of the test until peeling. It is used to measure relationships. This means that when evaluating the shear adhesion strength characteristics of laminates, the conventional shear adhesion strength test, which measures only the maximum strength at the time of peeling, is insufficient; This was done because we recognized that it is important to measure the relationship between the amount of shear deformation and strength.

(Function) In the test, the test piece formed in the rectangular shape is placed on the top surface of the fixed pedestal of the test device, and the end face of the lower layer material of the upper and lower layers sandwiching the bonded part to be tested is Bring it into contact with the upper side of the step of the fixed pedestal.
Next, a load is applied mainly from below the fixed pedestal, a predetermined load is applied to the test piece sandwiched between the fixed pedestal and the pull-out bar in a direction perpendicular to the surface, and then the pull-out bar is moved by the pull-out bar moving means. At this time, the lower side of the step formed on the lower surface of the pull-out bar is
The bonding surface is in contact with the end surface of the upper layer material that sandwiches the adhesive part of the test piece of the test piece, and the adhesive surface and The pull bar shall be moved so that loads are applied in parallel and opposite directions.

As a result, shear deformation occurs at the bonded area of the test piece, so measure and record the pullout load and the amount of movement of the pullout bar using the measuring device of the test equipment, and divide the maximum pullout load by the area of the bonded area. Then,
The shear adhesion strength of the test piece can be determined.

[Embodiments of the invention]

Fig. 1 is a partial cross-sectional side view of a test device for testing the shear adhesion strength of a laminate according to an embodiment of the present invention, Fig. 2 is a perspective view of a test piece, and Fig. 3 is an enlarged view of a stepped portion. . In the figure, 10 is a test piece, 11 is a fixed pedestal, 12 is a step, 13 is a hydraulic cylinder, 14 is a pull-out bar,
15 is a step, 16 is an upper fixed support part, 17 is a pull-out mechanism, 18 is a measuring device, and 19 is a groove.

In FIG. 1, the fixed pedestal 11 has a step 12 on the top surface.
It is equipped with a hydraulic cylinder 13 at the bottom, and cannot be moved left and right, but can be moved up and down. The pull-out bar 14 has a step 12 on the lower surface of the fixed base 11.
A step 15 is formed in the opposite direction, and an upper fixed support part 16 is disposed at the upper part. The pull bar 1
4 is movable in the left and right horizontal directions by a pull-out mechanism 17. A measuring device 18 is installed at one end of the pulling mechanism 17.
is connected so that the amount of movement of the pull-out bar 14 and the pull-out load can be measured. The shapes of the steps 12 and 15 formed on the fixed pedestal 11 and the pull-out bar 14 are as shown in FIG. 19 is formed.

The test piece 10 is formed into a rectangular shape as shown in Fig. 2 from a three-layer laminate consisting of two steel plates with a viscoelastic material sandwiched between them, and the end faces are machined to be perpendicular to the top and bottom faces. It is finished.

In the test, the test piece 10 is placed on the fixed pedestal 11 of the test device, and the end surface of the lower steel plate 2 of the test piece 10 is brought into contact with the upper side of the step 12. At this time, a gap of λ is provided between the end surface of the lower steel plate that is brought into contact with the step 12 of the fixed pedestal 11 and the end surface of the upper layer steel plate on the opposite side and the step 15 of the pull-out bar 14. Then, actuate the hydraulic cylinder 13,
A predetermined surface pressure is applied to the test piece 10 sandwiched between the fixed pedestal 11 and the pull-out bar 14, and in this state, the pull-out mechanism 17 is operated to remove the pull-out bar 14.
to move horizontally (in the direction of the arrow). As a result, the step 15 of the pull-out bar 14 comes into contact with the end surface of the upper steel plate of the test piece 10 and further presses it. Since the end surface of the test piece 10 on the opposite side of the lower steel plate is in contact with the step 12 of the fixed pedestal 11, the test piece 10
Shear deformation occurs at the bonded part. Therefore, the measuring device 1 measures the pull-out load of the pull-out bar and the amount of movement of the pull-out bar, that is, the amount of shear deformation applied to the bonded part.
8, and by dividing the maximum load by the area of the bonded area, the shear adhesion strength can be determined.

As described above, in the present invention, since the test piece is a simple rectangle, no skill is required to form the test piece, and labor and time can be significantly reduced.

Further, the end face of the test piece may be finished by precision punching instead of machining, so that it covers the steps 12 and 15 of the fixed pedestal or the pull-out bar.

Furthermore, the test specimen can be significantly miniaturized and can even be formed from pressed parts, which is difficult to do using conventional methods.

When the test piece has three layers, the height of the steps 12 and 15 provided on the fixed pedestal 11 and the pull-out bar 14 is preferably 1/3 or more of the thickness of the lower layer and the upper layer, respectively. Of course, the upper limit of the thickness is the thickness of the lower layer and the upper layer.

The above example is an example in which the test piece 10 has a three-layer structure, but in the case of a multi-layer structure with more than three layers, consider the three layers immediately above and immediately below the interface to be tested, and each layer sandwiching the interface. The height of the step may be determined so that the upper or lower side of the step comes into contact with the end face of the step.
Therefore, by preparing several pedestals 11 and pull-out bars 14 with different step heights, or by providing a mechanism that can adjust the step heights, it is possible to stack more than three layers. be.

In the above embodiment, the hydraulic cylinder 13 is provided below the pedestal 11 as a means for applying surface pressure to the test piece, but the hydraulic cylinder 13 may be provided above the pull-out bar 14. Note that the means for applying surface pressure is not limited to the hydraulic cylinder, and other mechanisms may be used.

Also, when placing the test piece 10 on the fixed pedestal 11, the step 12 of the fixed pedestal 11 and the step 1 of the pull-out bar 14 are removed.
5 is larger than the length of the test piece 10 by λ. This is the pull-out bar 1 at the start of the test.
4, the frictional force acting between the lower surface of the pull-out bar 14 and the upper surface of the test piece 10 is measured.
This is to determine the net shear deformation resistance value by subtracting the frictional force from the pull-out load after measuring the pull-out load after shearing is started by contacting the end face of the upper layer. The value of λ depends on the test speed, but it is 1 mm.
Any above is sufficient.

Moreover, the above-mentioned vertical load may change not only the frictional force but also the shear deformation resistance of the bonded portion. FIG. 4 shows the results of an experiment conducted to confirm this. If the vertical surface pressure applied to the test piece 10 is excessive, the shear adhesion strength tends to decrease, but according to the diagram in Fig. 4, the surface pressure of 50
It can be seen that if it is less than Kgf/ ^cm2 , it will not be affected. Therefore, during the test, the surface pressure was 50Kgf/cm ²
It should be:

〔Effect of the invention〕

The present invention uses the test device as described above,
Since the shear adhesion strength of the laminate was measured using a test piece formed into a rectangular shape, we were able to achieve excellent effects as described below.

(1) The labor and time required to form test specimens were significantly reduced. In other words, according to an experiment using 50 test pieces of 10 types, it took 4 minutes to cut out the test piece of the present invention and 30 minutes to machine the end face.34
In contrast, with the conventional method, it took 4 minutes to cut out the small plate, about 50 minutes to machine the end face, and 840 minutes to form the notch, for a total of 894 minutes. In other words, the time required to form a test piece using the method of the present invention was reduced to 1/26 compared to the conventional method.

(2) Test accuracy has been improved. Figure 5 shows 20 test pieces each with a three-layer structure in which resin is sandwiched between two steel plates.
FIG. It can be seen that the method of the present invention has less variation than the conventional method.

FIG. 6 shows the experimental results when the same intermediate layer (self-bonding resin) was sandwiched between steel plates of different thicknesses, where the white circles are the data of the method of the present invention and the black circles are the data of the conventional method. In the conventional method, the shear adhesion strength decreases as the steel plate thickness decreases, whereas in the method of the present invention, the shear adhesion strength is almost constant regardless of the steel plate thickness. In the case of the conventional method, the above tendency appears due to the peeling force mentioned above, and as the thickness of the steel sheet decreases, large bends occur.
Along with this, the peeling force also increases, and it is thought that the test value decreases. The large variations in the conventional method shown in FIG. 5 are also due to the instability of this peeling force.

[Brief explanation of drawings]

Figures 1 to 3 show one embodiment of the present invention, with Figure 1 being a partially sectional side view of the test device, Figure 2 being a perspective view of the test piece, and Figure 3 being an enlarged view of the stepped portion. FIG. Figure 4 is a diagram showing the relationship between surface pressure applied to the test piece and shear adhesion strength, Figures 5 and 6 are diagrams showing the experimental results, and Figure 7 is a perspective view of a conventional test piece. . In the figure, 10 is a test piece, 11 is a fixed pedestal, 12,1
5 is a step, 13 is a hydraulic cylinder, 14 is a pull-out bar, 16 is an upper fixed support part, 17 is a pull-out mechanism,
18 is a measuring device, and 19 is a groove.

Claims (1)

[Scope of Claims] 1. A test device for determining the shear adhesion strength of a bonded portion of a laminate having a multilayer structure of three or more layers is fixed to a rectangular test piece with a step formed on the top surface. a pedestal; a horizontally movable pull-out bar located on the upper part of the fixed pedestal with the test piece sandwiched therebetween and having a step formed on the lower surface in a direction opposite to the step of the fixed pedestal; and upper and lower surfaces of the test piece. means for applying a predetermined load in a direction perpendicular to the plane of the pull-out bar; means for regulating the upward movement of the pull-out bar and moving the pull-out bar in the horizontal direction; the amount of movement of the pull-out bar and the pull-out load; A shear adhesion strength testing device characterized by comprising: a measuring device for measuring and; 2. Claim 1, characterized in that the upright portion of the step formed on the fixed pedestal and pull-out bar of the test device is inclined inward by 5 to 10 degrees, and grooves are formed at the corners of the step. Test equipment for shear adhesion strength as described.