Test method for viscoelasticity of thermoplastic acrylic pressure-sensitive adhesive

Abstract

This invention relates to the field of thermoplastic acrylic pressure-sensitive adhesives and discloses a method for testing the viscoelasticity of thermoplastic acrylic pressure-sensitive adhesives. Before conducting the "oscillation mode" temperature scanning test of thermoplastic acrylic pressure-sensitive adhesive materials using a flat plate rheometer, this invention uses other analytical testing equipment to measure the glass transition temperature of the material. Then, based on the inherent characteristics of the pressure-sensitive adhesive, the softening temperature is determined. The entire temperature scanning range is divided into three temperature segments using the glass transition temperature and the softening temperature. When setting the axial force, different axial forces are set according to the three different states of the material. This effectively avoids the phenomenon of the test material being squeezed out of the test platform during the test, and can stably, realistically, and accurately reflect the viscoelasticity of the material.

Description

Technical Field

[0001] This invention relates to the field of acrylic pressure-sensitive adhesives, specifically a test method for the viscoelasticity of thermoplastic acrylic pressure-sensitive adhesives. Background Technology

[0002] During the testing process, it was found that because the test scanned from low temperature to high temperature, the fixed axial force was set based on the material in the glassy state. If the same axial force was used for the material in three different states (glassy state, elastic state, and viscous flow state) during the temperature scan, the material in the elastic and viscous flow states would be squeezed out of the test platform due to the excessive axial force, causing the test to be impossible or partially overflowing. This would form a thin layer of random thickness on the stainless steel test platform and stainless steel probe. Because the stainless steel test platform and stainless steel probe provide support for this layer, the test data for the elastic and viscous flow states would be too large, failing to reflect the true performance of the material and resulting in unstable test data. Summary of the Invention

[0003] The purpose of this invention is to provide a test method for the viscoelasticity of thermoplastic acrylic pressure-sensitive adhesives, so as to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0005] The test method for the viscoelasticity of thermoplastic acrylic pressure-sensitive adhesive includes the following steps:

[0006] S1: Before testing, the thermoplastic acrylic pressure-sensitive adhesive is allowed to stand and be kept at a constant temperature to obtain the sample A to be tested;

[0007] S2: Test the glass transition temperature of sample A; determine the softening temperature;

[0008] S3: Stack the test samples A and then cut them to obtain test sample B;

[0009] S4: Perform an oscillation test on the sample B to be tested. Divide the temperature during the test into three temperature ranges according to the glass transition temperature and softening temperature, and set different axial forces according to different temperature ranges to test the storage modulus and loss modulus of the sample B to be tested.

[0010] S5: The adhesiveness and elasticity of thermoplastic acrylic pressure-sensitive adhesive are characterized by storage modulus and loss modulus.

[0011] Furthermore, the temperature range is a glassy state temperature range, a highly elastic state temperature range, and a viscous flow state temperature range.

[0012] Furthermore, the glassy state temperature range is the temperature range before the temperature of the sample B to be tested reaches the glass transition temperature; the high elasticity temperature range is the temperature range between the glass transition temperature and the softening temperature of the sample B to be tested; and the viscous flow temperature range is the temperature range after the temperature of the sample B to be tested exceeds the softening temperature.

[0013] Furthermore, in step S4, during the oscillation test, when the temperature range of the sample B to be tested reaches the glassy state temperature range, the axial force is set to 0.6-1.0N; when the temperature range of the sample B to be tested reaches the high elastic state temperature range, the axial force is set to 0.2-0.6N; when the temperature range of the sample B to be tested reaches the viscous flow state temperature range, the axial force is set to 0.1-0.12N.

[0014] Furthermore, the characterization is as follows: the storage modulus at -40℃ and -20℃ characterizes the elasticity of the thermoplastic acrylic pressure-sensitive adhesive at low temperatures; the loss modulus at -40℃ and -20℃ characterizes the tackiness of the thermoplastic acrylic pressure-sensitive adhesive at low temperatures; the storage modulus at 23℃ characterizes the elasticity of the thermoplastic acrylic pressure-sensitive adhesive at room temperature; the loss modulus at 23℃ characterizes the tackiness of the thermoplastic acrylic pressure-sensitive adhesive at room temperature; the storage modulus at 85℃ characterizes the elasticity of the thermoplastic acrylic pressure-sensitive adhesive at high temperatures; and the loss modulus at 85℃ characterizes the tackiness of the thermoplastic acrylic pressure-sensitive adhesive at high temperatures.

[0015] Furthermore, in step S2, a differential scanning calorimeter (DSC-203F) is used to test the glass transition temperature of the sample A to be tested.

[0016] Furthermore, in step S3, the stacking thickness is 250-350μm; the cutting process involves stacking the sample to be tested in step S3 with a thickness of 250-350μm and then cutting the stacked sample A into a circle with a diameter of 7.8-8.2mm.

[0017] Furthermore, in step S4, the instrument used for the oscillation test is a flat plate rheometer; wherein, the strain in the oscillation test mode is set to 0.098-0.102%; the frequency in the oscillation test mode is set to 0.98-1.02Hz; and the heating rate in the oscillation test mode is set to 4.9-5.1℃ / min.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: Before conducting the "oscillation mode" temperature scanning test of thermoplastic acrylic pressure-sensitive adhesive material using a flat plate rheometer, the present invention uses other analytical testing equipment (differential scanning calorimeter) to measure the glass transition temperature of the material, and then determines the softening temperature according to the characteristics of the pressure-sensitive adhesive itself. The entire temperature scanning range is divided into three temperature segments (glassy state temperature segment, elastic state temperature segment, and viscous flow state temperature segment) using the glass transition temperature and softening temperature. When setting the axial force, different axial forces are set according to the three different states of the material (glassy state, elastic state, and viscous flow state). The axial force is set to 0.80±0.2N for the glassy state temperature segment, 0.40±0.2N for the elastic state temperature segment, and 0.11±0.1N for the viscous flow state. This can effectively avoid the phenomenon of the test material being squeezed out of the test platform during the test, and can stably, truly, and accurately reflect the viscoelasticity of the material. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a flowchart of the testing method of the present invention;

[0021] Figure 2 This is a schematic diagram of the temperature range of the present invention;

[0022] Figure 3 This is a graph showing the test data for sample number 1;

[0023] Figure 4 This is the test data graph for sample number 2;

[0024] Figure 5 This is the test data graph for sample number 3;

[0025] Figure 6 This is the test data graph for sample number 4;

[0026] Figure 7 This is the test data chart for sample number 5;

[0027] Figure 8 This is the test data chart for sample number 6;

[0028] Figure 9 This is the test data chart for sample number 7;

[0029] Figure 10 This is the test data chart for sample number 8;

[0030] Figure 11 This is the test data chart for sample number 9;

[0031] Figure 12 This is the test data chart for sample number 10;

[0032] Figure 13 This is the test data chart for sample number 11;

[0033] Figure 14 This is the test data graph for sample number 12. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In the following examples, the raw materials BPS P-162N and BXX4805 for the thermoplastic acrylic pressure-sensitive adhesive samples were provided by Shanghai Toyo Ink Manufacturing Co., Ltd.

[0036] The thermoplastic acrylic pressure-sensitive adhesive sample to be tested was prepared according to the following method:

[0037] Mix the main agent BPS P-162N and BXX4805 evenly at a mass ratio of 100:1, apply the mixture to a 50μm thick film using a manual coating machine, and cure at 40℃ for 72 hours to obtain the thermoplastic acrylic pressure-sensitive adhesive sample to be tested.

[0038] Twelve thermoplastic acrylic pressure-sensitive adhesive samples were prepared with a thickness of 300 μm and a diameter of 8 mm. The samples were numbered 1 to 12. Samples 1-3 were tested using existing methods to measure the storage modulus G′ and loss modulus G′ of the glassy, ​​elastic, and viscous states. Samples 4-6 were tested using the method of this patent to measure the storage modulus G′ and loss modulus G′ of the glassy state. Samples 7-9 were tested using the method of this patent to measure the storage modulus G′ and loss modulus G′ of the elastic state. Samples 10-12 were tested using the method of this patent to measure the storage modulus G′ and loss modulus G′ of the viscous state.

[0039] Existing testing methods include:

[0040] S1: Before testing, the thermoplastic acrylic pressure-sensitive adhesive was left to stand for 2 hours in an environment with a temperature of 23℃ and a humidity of 50% to obtain the test sample A;

[0041] S2: The glass transition temperature and softening temperature of the sample A were tested using a differential scanning calorimeter DSC-203F; the glass transition temperature was found to be -35℃ and the softening temperature to be 40℃.

[0042] S3: Stack the sample A to be tested to a thickness of 300μm and then cut it into a circle with a diameter of 8mm to obtain the sample B to be tested;

[0043] S4: Use a TA-HR10 rheometer to perform an oscillation test on the sample B under test. Set the same axial force and test the storage modulus and loss modulus of the sample B under test at different temperatures.

[0044] S5: The storage modulus at -40℃ and -20℃ characterizes the elasticity of thermoplastic acrylic pressure-sensitive adhesive at low temperatures; the loss modulus at -40℃ and -20℃ characterizes the tackiness of thermoplastic acrylic pressure-sensitive adhesive at low temperatures; the storage modulus at 23℃ characterizes the elasticity of thermoplastic acrylic pressure-sensitive adhesive at room temperature; the loss modulus at 23℃ characterizes the tackiness of thermoplastic acrylic pressure-sensitive adhesive at room temperature; the storage modulus at 85℃ characterizes the elasticity of thermoplastic acrylic pressure-sensitive adhesive at high temperatures; and the loss modulus at 85℃ characterizes the tackiness of thermoplastic acrylic pressure-sensitive adhesive at high temperatures.

[0045] The testing method of this patent includes:

[0046] S1: Before testing, the thermoplastic acrylic pressure-sensitive adhesive was left to stand for 2 hours in an environment with a temperature of 23℃ and a humidity of 50% to obtain the test sample A;

[0047] S2: The glass transition temperature and softening temperature of the sample A were tested using a differential scanning calorimeter DSC-203F; the glass transition temperature was found to be -35℃ and the softening temperature to be 40℃.

[0048] S3: Stack the sample A to be tested to a thickness of 300μm and then cut it into a circle with a diameter of 8mm to obtain the sample B to be tested;

[0049] S4: Use a TA-HR10 rheometer to perform an oscillation test on the sample B under test, set different axial forces, and test the storage modulus and loss modulus of the sample B under test at different temperatures.

[0050] S5: The storage modulus at -40℃ and -20℃ characterizes the elasticity of thermoplastic acrylic pressure-sensitive adhesive at low temperatures; the loss modulus at -40℃ and -20℃ characterizes the tackiness of thermoplastic acrylic pressure-sensitive adhesive at low temperatures; the storage modulus at 23℃ characterizes the elasticity of thermoplastic acrylic pressure-sensitive adhesive at room temperature; the loss modulus at 23℃ characterizes the tackiness of thermoplastic acrylic pressure-sensitive adhesive at room temperature; the storage modulus at 85℃ characterizes the elasticity of thermoplastic acrylic pressure-sensitive adhesive at high temperatures; and the loss modulus at 85℃ characterizes the tackiness of thermoplastic acrylic pressure-sensitive adhesive at high temperatures.

[0051] The settings for the TA-HR10 rheometer when testing samples numbered 1-12 are as follows:

[0052] Serial Number name Axial force Scanning temperature strain frequency 1 Example 1 of partial overflow in existing methods 1N -80 to 200℃ 0.1％ 1HZ 2 Example 2 of partial overflow in existing methods 1N -80 to 200℃ 0.1％ 1HZ 3 Example 3 of partial overflow in existing methods lN -80 to 200℃ 0.1％ 1HZ 4 Example 1 of the method in this article: glassy state 1N -80 to -35℃ 0.1％ 1HZ 5 Example 2 of the method in this article: Glassy state 1N -80 to -35℃ 0.1％ 1HZ 6 Example 3 of the method in this article: Glassy state 1N -80 to -35℃ 0.1％ 1HZ 7 Example 1 of the method in this paper: High Elasticity State 0.5N -35 to 40℃ 0.1％ 1HZ 8 Example 2 of the method in this paper: High Elasticity State 0.5N -35 to 40℃ 0.1％ 1HZ 9 Example 3 of the method in this paper: High Elasticity State 0.5N -35 to 40℃ 0.1％ 1HZ 10 Example 1 of the method in this paper on viscous flow. 0.1N 40 to 200℃ 0.1％ 1HZ 11 Example 2 of the method in this paper on viscous flow. 0.1N 40 to 200℃ 0.1％ 1HZ 12 Example 3 of the method in this paper on viscous flow. 0.1N 40 to 200℃ 0.1％ 1HZ

[0053] The experimental results are shown in the table below:

[0054]

[0055] in conclusion:

[0056] 1. Existing methods have poor stability in partial overflow test data, while the method in this paper has better stability in test data.

[0057] 2. Comparing the existing methods with the method in this paper, the data measured by the two methods in the glassy state are similar; in the elastic and viscous states, the data measured by the existing methods in the partial overflow state are generally greater than the data measured by the method in this paper.

[0058] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for testing the viscoelasticity of a thermoplastic acrylic pressure sensitive adhesive, characterized by: The method comprises the following steps: S1: thermoplastic acrylic pressure-sensitive adhesive is placed and kept constant temperature before testing to obtain a sample A to be tested; S2: the glass transition temperature and the softening temperature of the sample A to be tested are tested by using a differential scanning calorimeter; S3: the sample A to be tested is stacked and cut to obtain a sample B to be tested; S4: the sample B to be tested is subjected to oscillation testing, the temperature during the testing is divided into three temperature sections according to the glass transition temperature and the softening temperature, different axial forces are set according to different temperature sections to test the storage modulus and the loss modulus of the sample B to be tested, so that the test material is prevented from being extruded and overflowing the test platform during the testing; S5: the storage modulus and the loss modulus are used to characterize the viscosity and elasticity of the thermoplastic acrylic pressure-sensitive adhesive.

2. The method of claim 1, wherein the thermoplastic acrylic pressure-sensitive adhesive is tested for viscoelasticity. The three temperature sections are a glassy temperature section, an elastomeric temperature section and a viscous-liquid temperature section.

3. The method of claim 2, wherein the thermoplastic acrylic pressure-sensitive adhesive is tested for viscoelasticity. The glassy temperature section is a temperature section before the temperature of the sample B to be tested reaches the glass transition temperature, the elastomeric temperature section is a temperature section between the glass transition temperature and the softening temperature of the sample B to be tested, and the viscous-liquid temperature section is a temperature section after the temperature of the sample B to be tested exceeds the softening temperature.

4. The method of claim 1, wherein the thermoplastic acrylic pressure-sensitive adhesive is tested for viscoelasticity. In step S4, during the oscillation testing, the axial force is set to 0.6-1.0 N when the temperature of the sample B to be tested is in the glassy temperature section, the axial force is set to 0.2-0.6 N when the temperature of the sample B to be tested is in the elastomeric temperature section, and the axial force is set to 0.1-0.12 N when the temperature of the sample B to be tested is in the viscous-liquid temperature section.

5. The method of claim 1, wherein the thermoplastic acrylic pressure-sensitive adhesive is tested for viscoelasticity. The storage modulus at-40℃ and-20℃ is used to characterize the elasticity of the thermoplastic acrylic pressure-sensitive adhesive at low temperature, the loss modulus at-40℃ and-20℃ is used to characterize the viscosity of the thermoplastic acrylic pressure-sensitive adhesive at low temperature, the storage modulus at 23℃ is used to characterize the elasticity of the thermoplastic acrylic pressure-sensitive adhesive at room temperature, the loss modulus at 23℃ is used to characterize the viscosity of the thermoplastic acrylic pressure-sensitive adhesive at room temperature, the storage modulus at 85℃ is used to characterize the elasticity of the thermoplastic acrylic pressure-sensitive adhesive at high temperature, and the loss modulus at 85℃ is used to characterize the viscosity of the thermoplastic acrylic pressure-sensitive adhesive at high temperature.

6. The method of claim 1, wherein the thermoplastic acrylic pressure-sensitive adhesive is tested for viscoelasticity. In step S3, the stacking thickness is 250-350μm, and the cutting treatment is to cut the stacked sample A into a circle with a diameter of 7.8-8.2mm.

7. The method of claim 1, wherein the thermoplastic acrylic pressure-sensitive adhesive is tested for viscoelasticity. In step S4, the instrument used for the oscillation testing is a flat plate rheometer, wherein the strain in the oscillation testing mode is set to 0.098-0.102%, the frequency in the oscillation testing mode is set to 0.98-1.02Hz, and the temperature rising rate in the oscillation testing mode is set to 4.9-5.1℃ / min.

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