A test method for the open time of a two-component polyurethane adhesive
The method of tapping the glue gun into a glue strip and pressing it quickly with a thin round rod has solved the complex and inaccurate problem of existing testing methods, and achieved rapid and accurate determination of the opening time of two-component polyurethane adhesive, simplifying the operation process. Improves the reliability of test results.
Patent Information
- Application Number
- CN202210698540.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-06-20
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2042-06-20
AI Technical Summary
The test methods for the opening time of existing two-component polyurethane adhesives are complex and cumbersome, and the results of common methods are inaccurate, making it difficult to unify standards, which affects the formulation of practical application process parameters.
The two-component polyurethane adhesive is beaten into a glue strip using a glue gun, and quickly press and pull out through a thin round rod to compare the size of the pit. If the round pit is larger than the threshold, the recording time is the opening time, which simplifies operation and improves the accuracy of the test.
It provides a simple, fast and accurate test method without specific equipment, the test results are stable, conform to the actual opening time, and have the accuracy of guiding process parameters.
Smart Images
Figure CN115144568B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of adhesives, and in particular to a method for testing the open time of a two-component polyurethane adhesive. Background Art
[0002] Adhesives have the advantages of being able to connect the same or different materials, no stress concentration at the joints, high bonding strength, and easy to automate, and are widely used in various fields of the national economy, and have become an indispensable chemical product in the development of the national economy. The rapid development of the national economy has also provided a broad space for the development of the adhesive industry. my country has now become a major producer and consumer of adhesives and adhesive tapes.
[0003] In addition to the continued rapid growth in production and sales volume, the technical level of adhesives in my country's adhesive industry has also been continuously improved. A large number of products that have reached international advanced levels have been developed, and the products are developing in the direction of modified, reactive, multifunctional, and nano-type, and the application areas are focusing on emerging industries such as new energy, energy conservation and environmental protection.
[0004] Two-component polyurethane adhesives have excellent bonding properties to a variety of substrates because they contain isocyanate and carbamate groups with high chemical activity and strong polarity. In addition, the strength and toughness, open time and curing speed of two-component polyurethane adhesives are adjustable, and there is a large design space. At the same time, they have excellent low-temperature resistance, wear resistance, oil resistance, solvent resistance, and chemical resistance, so they have been widely used.
[0005] In the actual application process, whether two-component polyurethane adhesive can meet the application requirements is closely related to the performance of the adhesive itself, and the use process is also crucial. The open time of two-component polyurethane adhesive, as an important performance to guide the formulation of adhesive use process parameters, needs to be accurately measured.
[0006] Currently, there are four main ways to test the opening time:
[0007] 1) After the two components of the two-component polyurethane adhesive are mixed and evenly coated on the substrate, they are left for a period of time before bonding. The bonding strength after complete curing is tested and compared with the bonding strength after immediate bonding and complete curing. Generally speaking, the longest standing time for the bonding strength of the former to reach 90% of the bonding strength of the latter is the open time.
[0008] 2) Mix a certain amount of two components of a two-component polyurethane adhesive evenly and inject them into a container of a certain volume to test the change in viscosity over time. Generally speaking, when the viscosity rises to a certain value or reaches several times the initial viscosity, it is the disc life.
[0009] 3) Mix a certain amount of the two components of the two-component polyurethane adhesive evenly and put them into a container of a certain volume. The time it takes for a bamboo stick to stand upright is the gel time.
[0010] 4) Mix the two components of the two-component polyurethane adhesive evenly and apply them to the substrate. Use a PE film to place it on the surface of the adhesive. When there is no residual adhesive on the surface of the PE film when it is removed, it is the surface drying time.
[0011] The first method can accurately test the open time, but the operation is complicated, the workload is large, and the cycle is long. The test results of the last three methods can only be used as a reference for the open time, which is quite different from the actual open time. In addition, there are disadvantages such as difficulty in unifying the judgment standard, great influence by the amount of glue, large fluctuation of the test results, and the need for specific viscometer equipment. Summary of the invention
[0012] In order to solve the above technical problems, the object of the present invention is to provide a method for testing the open time of a two-component polyurethane adhesive.
[0013] The technical solution of the present invention is as follows:
[0014] A method for testing the open time of a two-component polyurethane adhesive, characterized in that it comprises the following steps:
[0015] S1. Use a glue gun to apply the two-component polyurethane adhesive to the substrate in the form of a well-mixed adhesive strip, and start timing after the application is completed;
[0016] S2, using one end of a thin round rod to quickly press the rubber strip to the bottom substrate in the vertical direction, and then quickly pull it out;
[0017] S3. Compare the sizes of the pit formed by the thin round rod pressing the rubber strip and the threshold round pit. If the pit formed by pressing the rubber strip is smaller than the threshold round pit, clean the glass rod until there is no residual glue, repeat step S2 at intervals on the rubber strip. If the pit formed by pressing the rubber strip is larger than or equal to the threshold round pit, record the time, which is the open time.
[0018] Furthermore, the substrate is a sheet of hard plastic or metal.
[0019] Furthermore, the hard plastic is polytetrafluoroethylene.
[0020] Furthermore, the time from the start of gluing to the start of timing in step S1, that is, the gluing time is less than 10 seconds.
[0021] Furthermore, the gluing time is less than 5s.
[0022] Furthermore, the width of the adhesive strip is 3-20 mm, and the thickness is 3-20 mm.
[0023] Furthermore, the thin round rod is any one of a glass rod, a metal rod, and a plastic rod, and the diameter of the thin round rod is at least 2 mm smaller than the width of the rubber strip.
[0024] Furthermore, the time interval between two consecutive quick presses and quick dialing is 30s, 15s, 10s or 5s.
[0025] Furthermore, the ambient temperature when measuring the open time is 0° C.-40° C. and the relative humidity is 10%-90%.
[0026] The invention discloses a test method for the open time of a two-component polyurethane adhesive and its application in the performance test and practical use of the two-component polyurethane adhesive.
[0027] By means of the above scheme, the present invention has at least the following advantages:
[0028] The test method for the open time of a two-component polyurethane adhesive provided by the present invention is simple, convenient, rapid, does not require specific equipment or instruments, has a unified test standard, is easy to judge the test result, has good stability, and the test result is accurate and equivalent to the actual open time, etc., and has accurate guiding significance for the formulation of process parameters for actual applications.
[0029] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 It is a structural schematic diagram of the testing tool of the present invention;
[0031] Figure 2 It is a schematic diagram of the structure of some test tools of the present invention;
[0032] Figure 3 It is a schematic diagram of the structure of the adhesive strip of the present invention;
[0033] In the figure:
[0034] 1-substrate; 2-bracket; 3-X-axis linear module; 4-Y-axis linear module; 5-Z-axis linear module; 6-connecting plate; 7-glue gun; 8-cylinder; 9-thin round rod; 10-visual inspection mechanism; 100-glue strip; 101-pit; 102-obvious pit. DETAILED DESCRIPTION
[0035] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0036] Example 1
[0037] In an environment with a temperature of 25°C and a relative humidity of 50%, a glue gun was used to mix the two-component polyurethane adhesive evenly and then applied it on a polytetrafluoroethylene plate. The width of the glue strip was 10 mm, the thickness was 5 mm, the length was 15 cm, and the gluing time was 5 s. The timing started after the gluing was completed. After 2 minutes, a glass rod with a diameter of 5 mm was used to start from one end of the glue strip, press vertically quickly and then pull it out quickly. After quickly cleaning the glass rod until there was no residual glue, the next quick vertical pressing and pulling out were performed at a distance of 10 mm from the previous pressing position after an interval of 10 seconds. At 3 minutes and 10 seconds, after quick pressing and pulling out, an obvious circular pit was formed. After 10 seconds, another quick vertical pressing and pulling out were performed at a distance of 10 mm from the circular pit, and an obvious circular pit was still formed, that is, the open time was 3 minutes and 10 seconds.
[0038] The opening time of the above-mentioned embodiment 1 was detected by conventional methods:
[0039] In an environment with a temperature of 25°C and a relative humidity of 50%, use a glue gun to mix the two-component polyurethane adhesive evenly, apply it on the surface of one substrate to be bonded, and the other substrate to be bonded is: 1) pressed and bonded immediately, 2) pressed and bonded after waiting for 1 minute, 3) pressed and bonded after waiting for 2 minutes, 4) pressed and bonded after waiting for 3 minutes, 5) pressed and bonded after waiting for 3 minutes and 15 seconds, 6) pressed and bonded after waiting for 3 minutes and 30 seconds. After complete curing at room temperature, the shear strength is tested respectively. The results are shown in Table 1 below.
[0040] As can be seen from Table 1, the opening time is about 3 min 15 s. This test result proves that the detection method of Example 1 is reliable and accurate.
[0041] Table 1 Example 1 Opening time using conventional method test results
[0042] Sample serial number 1 2 3 4 5 6 Based on 1) shear strength 100％ 98％ 96％ 93％ 91％ 85％
[0043] Example 2
[0044] In an environment with a temperature of 15°C and a relative humidity of 40%, a glue gun was used to mix the two-component polyurethane adhesive evenly and then applied to a stainless steel plate. The width of the glue strip was 8mm, the thickness was 6mm, the length was 20cm, and the gluing time was 7s. The timing started after the gluing was completed. After 2min30s, a glass rod with a diameter of 5mm was used, starting from one end of the glue strip, and then quickly pressed vertically and then quickly pulled out. After quickly cleaning the glass rod until there was no residual glue, the next quick vertical pressing and quick pulling were performed at a distance of 10mm from the previous pressing position after an interval of 10s. At 3min40s, after quick pressing and quick pulling out, an obvious circular pit was formed. After 10s, another quick vertical pressing and quick pulling out were performed at a distance of 10mm from the circular pit, and an obvious circular pit was still formed, that is, the open time was 3min40s.
[0045] The opening time of the above-mentioned embodiment 2 was detected by conventional methods:
[0046] In an environment with a temperature of 15°C and a relative humidity of 40%, the two-component polyurethane adhesive was mixed evenly with a glue gun and applied to the surface of one substrate to be bonded. The other substrate to be bonded was: 1) pressed and bonded immediately, 2) pressed and bonded after waiting for 1 minute, 3) pressed and bonded after waiting for 2 minutes, 4) pressed and bonded after waiting for 3 minutes, 5) pressed and bonded after waiting for 3 minutes and 40 seconds, and 6) pressed and bonded after waiting for 4 minutes. After complete curing at room temperature, the shear strength was tested respectively. The results are shown in Table 1 below.
[0047] As can be seen from Table 2, the opening time is about 3 minutes and 40 seconds. This test result proves that the detection method of Example 2 is reliable and accurate.
[0048] Table 2 Example 2 Opening time using conventional method test results
[0049] Sample serial number 1 2 3 4 5 6 Based on 1) shear strength 100％ 98％ 96％ 93％ 90％ 86％
[0050] Example 3
[0051] In an environment with a temperature of 35°C and a relative humidity of 60%, a glue gun was used to mix the two-component polyurethane adhesive evenly and then applied it on a polytetrafluoroethylene plate. The width of the glue strip was 12mm, the thickness was 7mm, the length was 15cm, and the gluing time was 6s. The timing started after the gluing was completed. After 1min30s, a glass rod with a diameter of 8mm was used, starting from one end of the glue strip, and then quickly pressed vertically and then quickly pulled out. After quickly cleaning the glass rod until there was no residual glue, the next quick vertical pressing and quick pulling were performed at a distance of 10mm from the previous pressing position after an interval of 5s. At 2min15s, after quick pressing and quick pulling out, an obvious circular pit was formed. After 5s, another quick vertical pressing and quick pulling out were performed at a distance of 10mm from the circular pit, and an obvious circular pit was still formed, that is, the open time was 2min15s.
[0052] The opening time of the above-mentioned embodiment 3 was detected by conventional methods:
[0053] In an environment with a temperature of 35°C and a relative humidity of 60%, the two-component polyurethane adhesive was mixed evenly with a glue gun and applied to the surface of one substrate to be bonded. The other substrate to be bonded was: 1) pressed and bonded immediately; 2) pressed and bonded after waiting for 1 minute; 3) pressed and bonded after waiting for 2 minutes; 4) pressed and bonded after waiting for 2 minutes and 15 seconds; 5) pressed and bonded after waiting for 2 minutes and 25 seconds. After complete curing at room temperature, the shear strength was tested respectively. The results are shown in Table 1 below.
[0054] It can be seen from Table 3 that the opening time is about 2 min 15 s. This test result proves that the detection method of Example 3 is reliable and accurate.
[0055] Table 3 Example 3 Opening time using conventional method test results
[0056] Sample serial number 1 2 3 4 5 Based on 1) shear strength 100％ 98％ 95％ 89％ 87％
[0057] In specific embodiments 1-3 of the present invention, the operations of gluing, pressing and pulling out can all be completed manually. The size of the circular pit formed after pressing can be compared with the threshold circular pit by manually observing whether the pit formed after pressing is an obvious circular pit.
[0058] In order to further improve the detection accuracy, the size of the circular pit formed after pressing is compared with the threshold circular pit through the visual detection mechanism 10. The visual detection mechanism 10 includes a camera, which is used to obtain the image after the round rod presses the rubber strip, and identify the area of the pit formed after pressing in the image. Specifically, the grayscale value of the edge pixel of the pit in the image is different from the surrounding area, and then the area of the pit is calculated through the identified edge trajectory. The area of the obtained pit is compared with the area of the threshold circular pit (90% of the cross-sectional area of the thin round rod). When the area of the obtained pit is greater than or equal to the area of the threshold circular pit, it is considered that an obvious pit is formed.
[0059] In a specific embodiment of the present invention, the aforementioned manual operation can be performed by automated equipment, completely replacing the manual operation to improve the accuracy of the operation.
[0060] The automation equipment includes a bracket 2 set on a substrate 1, an X-axis linear module 3 is set on the bracket 2, a Y-axis linear module 4 is set at the driving end of the X-axis linear module 3, a Z-axis linear module 5 is set at the driving end of the Y-axis linear module 4, a connecting plate 6 is set at the driving end of the Z-axis linear module 5, a glue gun 7, a cylinder 8 and a visual inspection mechanism 10 are sequentially arranged on the connecting plate 6, and a thin round rod 9 is connected to the driving end of the cylinder 8. The glue gun 7 has a first feed pipe 701 and a second feed pipe 702 on the upper part, and a mixing pipe 703 on the lower part. When in use, the first feed pipe 701 and the second feed pipe 702 are used to feed component A and component B of the adhesive respectively, and the mixing pipe 703 is used to mix the two components evenly and pump them out.
[0061] A detailed automated detection method flow is:
[0062] Driven by the three linear modules, the glue gun 7 punches out a glue strip 100 on the substrate 1, and then drives the thin round rod 9 through the cylinder 8 to press on the glue strip 100 to form a pit 101. The visual detection mechanism 10 detects the area of the pit 101 and compares it with the threshold circular pit area. If the area of the pit 101 is smaller than the threshold circular pit area, the above-mentioned operation of pressing to form the pit 101 is repeated at the next position until the visual detection mechanism 10 detects that the area of the pit 101 is greater than or equal to the threshold area. In this case, the pit 101 is an obvious pit 102, and the detection time of the above operation is the opening time.
[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be regarded as within the scope of protection of the present invention.
Claims
1. A test method for the open time of a two-component polyurethane adhesive. It is characterized in that The steps include: S1. Use a glue gun to apply the two-component polyurethane adhesive to the substrate in the form of a well-mixed adhesive strip, and start timing after the application is completed; S2, using one end of a thin round rod to quickly press the rubber strip to the bottom substrate in the vertical direction, and then quickly pull it out; S3, compare the size of the pit formed by the thin round rod pressing the rubber strip and the threshold round pit. If the pit formed by pressing the rubber strip is smaller than the threshold round pit, clean the glass rod until there is no residual glue, repeat step S2 at intervals on the rubber strip. If the pit formed by pressing the rubber strip is larger than or equal to the threshold round pit, record the time, which is the open time; The area of the threshold circular pit is 90% of the cross-sectional area of the thin round rod.
2. The method for testing the open time of a two-component polyurethane adhesive according to claim 1, Features: The substrate is a sheet of hard plastic or metal.
3. The method for testing the open time of a two-component polyurethane adhesive according to claim 2, Features: The hard plastic is polytetrafluoroethylene.
4. The method for testing the open time of a two-component polyurethane adhesive according to claim 1, Features: The time from the start of gluing to the start of the gluing in step S1 is less than 10 seconds.
5. The method for testing the open time of a two-component polyurethane adhesive according to claim 4, Features: The gluing time is less than 5s.
6. The method for testing the open time of a two-component polyurethane adhesive according to claim 1, Features: The width of the adhesive strip is 3-20 mm, and the thickness is 3-20 mm.
7. The method for testing the open time of a two-component polyurethane adhesive according to claim 1, Features: The thin round rod is any one of a glass rod, a metal rod and a plastic rod, and the diameter of the thin round rod is at least 2 mm smaller than the width of the rubber strip.
8. The method for testing the open time of a two-component polyurethane adhesive according to claim 1, Features: The time interval between two quick presses and quick dialing is 30s, 15s, 10s or 5s.
9. The method for testing the open time of a two-component polyurethane adhesive according to claim 1, Features: The ambient temperature when measuring the open time is 0°C-40°C and the relative humidity is 10%-90%.
10. Application of the method for testing the open time of a two-component polyurethane adhesive according to any one of claims 1 to 9 in the performance testing and actual use of the two-component polyurethane adhesive.