阅读说明：本技术 一种检测湿固化反应型聚氨酯热熔胶固化的方法 (Method for detecting curing of moisture-curing reaction type polyurethane hot melt adhesive ) 是由 徐文 于 2020-12-17 设计创作，主要内容包括：本发明公开了一种检测湿固化反应型聚氨酯热熔胶固化的方法,通过对热熔胶固化后不同时间段的邵氏硬度的检测,一方面可以得出热熔胶在该环境中的完全固化时间,另一方面,通过相同固化时间的热熔胶的不同硬度,可以检测出热熔胶使用前是否发生固化变质。本发明在操作上简单易行,可操作性强。(The invention discloses a method for detecting the solidification of a moisture-curing reactive polyurethane hot melt adhesive. The method is simple and easy to operate and strong in operability.)

1. A method for detecting the curing of a moisture-curing reaction type polyurethane hot melt adhesive is characterized by comprising the following steps:

s1, preheating the moisture-curing reaction type polyurethane hot melt adhesive for a period of time;

s2, after preheating, heating the moisture-curing reaction type polyurethane hot melt adhesive, then dispensing on the metal foil, and exposing the metal foil in the air for curing after dispensing;

s3, loosening a pressing screw at the upper right corner of the Shore durometer, rotating the surface to align with a zero position, pressing the durometer on a glass plate, enabling the end face of a pressing pin and the bottom face of a pressing foot to be in close contact with the glass plate, and slightly pressing the pressing pin to enable a pointer to point to 100+/-0.5 HA;

s4, after the hot melt adhesive is solidified for 0.5h, horizontally placing the glued metal foil on a firm plane, holding a hardness tester, stably pressing a pressure foot on the hot melt adhesive without any vibration, and keeping the pressure foot parallel to the surface of the sample so as to enable the pressure pin to vertically press the sample, wherein the applied force is just enough to enable the pressure foot to be completely contacted with the sample;

s5, reading within 1 second after the pressure foot and the hot melt adhesive are completely pressed, and measuring the hardness of the hot melt adhesive;

and S6, testing every 2h until the hardness measured in two consecutive times is unchanged, which indicates that the hot melt adhesive is completely cured.

2. The method for detecting the curing of the moisture-curing reactive polyurethane hot melt adhesive according to claim 1, wherein the method comprises the following steps: the preheating temperature in S1 is 90-100 ℃.

3. The method for detecting the curing of the moisture-curing reactive polyurethane hot melt adhesive according to claim 2, wherein the method comprises the following steps: the preheating time in S1 is 5-15 min.

4. The method for detecting the curing of the moisture-curing reactive polyurethane hot melt adhesive according to claim 1, wherein the method comprises the following steps: the heating temperature of the hot melt adhesive in S2 is 110-120 ℃.

5. The method for detecting the curing of the moisture-curing reactive polyurethane hot melt adhesive according to claim 1, wherein the method comprises the following steps: the dispensing amount of the hot melt adhesive in S2 is 150-250 g.

6. The method for detecting the curing of the moisture-curing reactive polyurethane hot melt adhesive according to claim 5, wherein the method comprises the following steps: the dispensing amount of the hot melt adhesive in S2 is 190-220 g.

7. The method for detecting the curing of the moisture-curing reactive polyurethane hot melt adhesive according to claim 5, wherein the method comprises the following steps: the thickness of the hot melt adhesive film obtained after dispensing is more than 6 mm.

8. The method for detecting the curing of the moisture-curing reactive polyurethane hot melt adhesive according to claim 7, wherein the method comprises the following steps: the thickness of the hot melt adhesive film obtained after dispensing is 6-8 mm.

9. The method for detecting the curing of the moisture-curing reactive polyurethane hot melt adhesive according to claim 1, wherein the method comprises the following steps: the presser pin of the hole in the presser foot in S4 is at least 12mm away from the edge of the test block.

10. The method for detecting the curing of the moisture-curing reactive polyurethane hot melt adhesive according to claim 1, wherein the method comprises the following steps: and (S5) changing the hot melt adhesive testing position and then testing to obtain the hot melt adhesive hardness, repeating for 3-5 times and then taking the average value.

Technical Field

The invention belongs to the technical field of hot melt adhesive detection, and particularly relates to a method for detecting the curing of a moisture-curing reaction type polyurethane hot melt adhesive.

Background

The complete curing time of the hot melt adhesive is of great significance to the use of the hot melt adhesive, and if the hot melt adhesive is not completely cured, other treatments are carried out on the product bonded by the hot melt adhesive, which may affect the normal performance of the hot melt adhesive and even cause the product to be scrapped.

In addition, the reactive polyurethane hot melt adhesive is very easy to react with moisture due to the characteristics of the reactive polyurethane hot melt adhesive, and the reactive polyurethane hot melt adhesive is cured and deteriorated to a certain extent in the packaging, storing and transporting process or before use due to the reaction with the moisture, so that a rubber tube gun head is blocked in the use process and the normal performance of the hot melt adhesive after use is influenced.

Disclosure of Invention

In order to solve the problems, the invention provides a method for detecting the curing of a moisture-curing reaction type polyurethane hot melt adhesive, which comprises the following steps:

s1, preheating the moisture-curing reaction type polyurethane hot melt adhesive for a period of time;

s2, after preheating, heating the moisture-curing reaction type polyurethane hot melt adhesive, then dispensing on the metal foil, and exposing the metal foil in the air for curing after dispensing;

s3, loosening a pressing screw at the upper right corner of the Shore durometer, rotating the surface to align with a zero position, pressing the durometer on a glass plate, enabling the end face of a pressing pin and the bottom face of a pressing foot to be in close contact with the glass plate, and slightly pressing the pressing pin to enable a pointer to point to 100+/-0.5 HA;

s4, after the hot melt adhesive is solidified for 0.5h, horizontally placing the glued metal foil on a firm plane, holding a hardness tester, stably pressing a pressure foot on the hot melt adhesive without any vibration, and keeping the pressure foot parallel to the surface of the sample so as to enable the pressure pin to vertically press the sample, wherein the applied force is just enough to enable the pressure foot to be completely contacted with the sample;

s5, reading within 1 second after the pressure foot and the hot melt adhesive are completely pressed, and measuring the hardness of the hot melt adhesive;

and S6, testing every 2h until the hardness measured in two consecutive times is unchanged, which indicates that the hot melt adhesive is completely cured.

As a preferable technical scheme, the preheating temperature in the S1 is 90-100 ℃.

As a preferable technical scheme, the preheating time in S1 is 5-15 min.

As a preferable technical scheme, the heating temperature of the hot melt adhesive in S2 is 110-120 ℃.

As a preferable technical scheme, the glue dropping amount of the hot melt glue in S2 is 150-250 g.

As a preferable technical scheme, the glue dropping amount of the hot melt glue in S2 is 190-220 g.

As a preferred technical scheme, the thickness of the hot melt adhesive film obtained after dispensing is more than 6 mm.

As a preferred technical scheme, the thickness of the hot melt adhesive film obtained after dispensing is 6-8 mm.

As a preferable technical scheme, in the S4, the press pin of the hole in the press foot is at least 12mm away from the edge of the test block.

As a preferred technical scheme, after the hardness of the hot melt adhesive is measured in S5, the test position of the hot melt adhesive is changed and then the test is carried out to obtain the hardness of the hot melt adhesive, and the hardness of the hot melt adhesive is repeated for 3-5 times and then the average value of the hardness is taken.

Has the advantages that:

according to the method, the shore hardness of the hot melt adhesive in different time periods after curing is detected, so that the complete curing time of the hot melt adhesive in the environment can be obtained, and whether the hot melt adhesive is cured or deteriorated before use can be detected through the different hardness of the hot melt adhesive in the same curing time, so that the complexity of detecting the content of the-NCO group is avoided. The method is simple and easy to operate and strong in operability.

Detailed Description

The invention will be further understood by reference to the following detailed description of preferred embodiments of the invention and the examples included therein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. To the extent that a definition of a particular term disclosed in the prior art is inconsistent with any definition provided in the present disclosure, the definition of the term provided in the present disclosure controls.

As used herein, a feature that does not define a singular or plural form is also intended to include a plural form of the feature unless the context clearly indicates otherwise. It will be further understood that the term "prepared from …," as used herein, is synonymous with "comprising," including, "comprising," "having," "including," and/or "containing," when used in this specification means that the recited composition, step, method, article, or device is present, but does not preclude the presence or addition of one or more other compositions, steps, methods, articles, or devices. Furthermore, the use of "preferred," "preferably," "more preferred," etc., when describing embodiments of the present invention, is meant to refer to embodiments of the invention that may provide certain benefits, under certain circumstances. However, other embodiments may be preferred, under the same or other circumstances. In addition, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

In order to solve the problems, the invention provides a method for detecting the curing of a moisture-curing reaction type polyurethane hot melt adhesive, which comprises the following steps:

s1, preheating the moisture-curing reaction type polyurethane hot melt adhesive for a period of time;

s2, after preheating, heating the moisture-curing reaction type polyurethane hot melt adhesive, then dispensing on the metal foil, and exposing the metal foil in the air for curing after dispensing;

s3, loosening a pressing screw at the upper right corner of the Shore durometer, rotating the surface to align with a zero position, pressing the durometer on a glass plate, enabling the end face of a pressing pin and the bottom face of a pressing foot to be in close contact with the glass plate, and slightly pressing the pressing pin to enable a pointer to point to 100+/-0.5 HA;

s4, after the hot melt adhesive is solidified for 0.5h, horizontally placing the glued metal foil on a firm plane, holding a hardness tester, stably pressing a pressure foot on the hot melt adhesive without any vibration, and keeping the pressure foot parallel to the surface of the sample so as to enable the pressure pin to vertically press the sample, wherein the applied force is just enough to enable the pressure foot to be completely contacted with the sample;

s5, reading within 1 second after the pressure foot and the hot melt adhesive are completely pressed, and measuring the hardness of the hot melt adhesive;

and S6, testing every 2h until the hardness measured in two consecutive times is unchanged, which indicates that the hot melt adhesive is completely cured.

In some preferred embodiments, the preheating temperature in S1 is 90-100 ℃.

In some preferred embodiments, the preheating time in S1 is 5-15 min.

In some preferred embodiments, the hot melt adhesive heating temperature in S2 is 110-120 ℃.

In some preferred embodiments, the amount of hot-melt adhesive dispensed in S2 is 150-250 g.

In some preferred embodiments, the amount of hot melt adhesive dispensed in S2 is 190-220 g.

In some preferred embodiments, the thickness of the hot melt adhesive film obtained after dispensing is greater than 6 mm.

In some preferred embodiments, the thickness of the hot melt adhesive film obtained after dispensing is 6-8 mm.

In some preferred embodiments, the pins in the holes of the presser foot in S4 are at least 12mm from the edge of the test block.

In some preferred embodiments, after the hot melt adhesive hardness is measured in S5, the hot melt adhesive test position is changed and then the test is performed, so as to obtain the hot melt adhesive hardness, and the hot melt adhesive hardness is repeated for 3-5 times and then the average value is taken.

The present invention will be specifically described below by way of examples. It should be noted that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and that the insubstantial modifications and adaptations of the present invention by those skilled in the art based on the above disclosure are still within the scope of the present invention.

In addition, the starting materials used are all commercially available, unless otherwise specified.

Examples

The technical solution of the present invention is described in detail by the following examples, but the scope of the present invention is not limited to the examples.

Example 1

Embodiment 1 provides a method for detecting curing of a moisture-curable reactive polyurethane hot melt adhesive, comprising the following steps:

s1, preheating the PUR-01 hot melt adhesive in an oven at 100 ℃ for 10 min;

s2, after preheating, picking out rubber scabs at the top and the tail of the PUR glue rubber tube, then mounting the PUR glue rubber tube on a stainless steel needle, heating the tube under a heater at 110 ℃, then carrying out dispensing on a metal foil, controlling the dispensing amount to be 200g, enabling the thickness of a hot melt adhesive film obtained after dispensing to be 7mm, and then exposing the hot melt adhesive film in the air for curing;

s3, loosening a pressing screw at the upper right corner of the Shore durometer, rotating the surface to align with a zero position, pressing the durometer on a glass plate, enabling the end face of a pressing pin and the bottom face of a pressing foot to be in close contact with the glass plate, and slightly pressing the pressing pin to enable a pointer to point to 100+/-0.5 HA;

s4, after the hot melt adhesive is solidified for 0.5h, horizontally placing the glued metal foil on a firm plane, holding a hardness tester, enabling a pressing pin in a hole of a pressing foot to be 15mm away from the edge of the test block, stably pressing the pressing foot on the hot melt adhesive without any vibration, and keeping the pressing foot parallel to the surface of the test sample so as to enable the pressing pin to vertically press the test sample, wherein the force applied is just enough to enable the pressing foot to be completely contacted with the test sample;

s5, reading within 1 second after the pressure foot and the hot melt adhesive are completely pressed, and measuring the hardness of the hot melt adhesive;

and S6, testing every 2h until the hardness measured in two consecutive times is unchanged, indicating that the hot melt adhesive is completely cured, and recording the test result in Table 1.

Table 1 shows the test results of 5 hot melt adhesives of the same type and different packages in the same environment according to the test method of example 1, wherein sample 5 is opened before the test and exposed to the air for 1 h.

TABLE 1

As can be seen from the above test results, the hardness of samples 1 to 4 does not substantially change after 8.5h, so that the full curing time of the hot melt adhesive is 8.5h, the full curing time of sample 5 is 6.5h, and the hardness of the sample at the same time before full curing is higher than that of samples 1 to 4, indicating that the sample 5 has undergone curing deterioration before testing and is consistent with the condition that the sample is exposed to air for 1h before testing.

According to the embodiments, the method for detecting the curing of the moisture-curing reaction type polyurethane hot melt adhesive can be used for detecting the time for completely curing the moisture-curing reaction type polyurethane hot melt adhesive and can also be used for detecting whether the moisture-curing reaction type polyurethane hot melt adhesive is cured and deteriorated before being used.

Finally, it should be understood that the above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.