JPS62103540A - Method for measuring curing time of organic adhesive - Google Patents

Abstract

PURPOSE:To realize a measuring method requiring no test piece and capable of obtaining a result reduced in irregularity, by measuring the curing time of an org. adhesive from the relation between the change in the transmissivity or absorbancy of an infrared absorption spectrum and an elapse time. CONSTITUTION:Measurement is performed according to the following process. That is, an adhesive is mixed to be held between two window panels and set to a specimen chamber in a first process and an infrared absorption spectrum is measured to obtain initial data in a second process. In a third process, the infrared absorption spectrum is again measured after a definite time to confirm a wave number region changing in transmissivity or absorbancy. At this time, some epoxy adhesive has a wave number region present in the vicinity of about 3,400cm. In a fourth process, the timewise change in the infrared absorption spectrum is measured and, in a fifth process, the curing time of the epoxy adhesive is calculated from the relation between the transmissivity or absorbancy of the wave number region having a change and an elapse time. By the above mentioned method, the material cost and processing cost relating to the formation of a test piece become unnecessary and the irregularity in a measuring result is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a method for measuring the curing time of an organic adhesive.

Furthermore, the present invention can also be applied to measuring the curing time of organic resins in general such as organic paints.

[Conventional technology]

As a typical example of a conventionally used method for measuring the curing time of an organic adhesive, a method for determining the curing time of an adhesive from the change in adhesive strength over time is shown below.

First, two adherends such as steel plates are prepared, and after polishing the adhesive surfaces of the adherends, the adhesive surfaces are degreased and cleaned. Next, after preparing the adhesive for the curing time measurement test by mixing the main component and curing agent, the adhesive is applied to the adhesive surface of the adherend, and the adhesive surface of the two adherends is coated. A test piece for measuring adhesive strength? The number of test pieces required to measure the curing time is prepared, and the test pieces thus prepared are measured at fixed time intervals using a tensile tester, etc. What is the relationship between adhesive strength and elapsed time? Is this test until there is no change in adhesive strength over time?
31- Give money. What is the relationship between the adhesive strength found in this way and the elapsed time? Estimate the curing time of the adhesive from the plot shown.

[Problem that the invention seeks to solve]

However, conventional methods for measuring the curing time of organic adhesives have the following drawbacks.

1) The number of test pieces is very large (usually 30 to 50 sets of test pieces are required for one type of adhesive)
The material cost and processing cost of the fc test piece are high, and the polishing process and degreasing cleaning ring? It takes a long time to make the test piece.

2) The adhesive strength of the test piece is greatly influenced by various conditions such as the surface treatment state of the adherend, its shape and dimensions, and the thickness of the adhesive. However, it is difficult to create test pieces with exactly the same conditions, and the measurement results vary widely.

3) Because it takes time from the time of gluing the test piece to the end of the adhesive strength measurement, it is difficult to measure the curing time of adhesives that have a particularly short curing time. [Problem? Means for Solving] As a result of intensive research to solve these problems, the present inventors have found that the curing time of organic adhesives can be determined based on changes in infrared absorption spectra over time. Can it be measured? Heading 2 This led to the invention.

That is, in measuring the curing time of an organic adhesive, the present invention determines the wave number region in which the transmittance or absorbance of the infrared absorption spectrum of the organic adhesive changes over time,
Provided is a method for measuring the curing time of an organic adhesive, characterized in that the curing time of the organic adhesive is measured from the relationship between the change in transmittance or absorbance of the infrared absorption spectrum in the wave number change region and the elapsed time. It is something.

[Effect]

In organic adhesives, as the monomer in the curing agent migrates to the polymer during the curing process.

As the molecular bonds change, the absorbance or transmittance in the absorption wavenumber region that constitutes the infrared absorption spectrum changes. By checking in advance the wave number region of the infrared absorption spectrum with this changing absorbance, and determining the change in absorbance or transmittance over time in that wave number region, we can determine the time at which it becomes constant. Estimate and measure curing time.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.The method for measuring the curing time of the epoxy adhesive is as follows.

1) Mix the adhesive and sandwich it between two window boards such as KH2.
Set it in the sample chamber.

2) Infrared absorption spectrum? Measure and obtain initial data.

3) After a certain period of time, measure the infrared absorption spectrum again and check the wavenumber region where transmittance or absorbance changes? confirm.

For epoxy adhesive, the wave number range is 3400cIrL
There's something nearby.

4) Measure the change in infrared absorption spectrum over time (the measurement time is 5 minutes/time).

5) The curing time of the epoxy adhesive can be determined from the relationship between the transmittance or absorbance in a changing wavenumber region and the elapsed time.

The curing time of epoxy adhesives was measured using the conventional method and the method according to the present invention. The results measured using the conventional method are shown in FIG. 2, and the results measured according to the present invention are shown in FIG. From the measurement results, the curing time was 5 hours in all cases.

The method according to the present invention produced better results with less variation than the conventional method.

〔Effect of the invention〕

1) When measuring the curing time of organic adhesives.

There is no need to use a test piece, and there is no need for material costs, processing costs, etc. related to test piece production.

2) There is very little variation in measurement results compared to conventional methods.

3) Since the time from mixing the adhesive to starting the measurement operation is short, it is possible to sufficiently measure even those with a short curing time.

4) By controlling the conditions such as temperature and humidity in the sample chamber of the infrared spectrometer, it is possible to easily understand the influence of various conditions on one curing time.

5) Since there is no need to prepare a test heath tray, the time required to measure one curing time is extremely short compared to the conventional method.

[Brief explanation of drawings]

Figure 1 shows the measurement results of the curing time of an epoxy adhesive according to one embodiment of the present invention. The figure shown in Figure 2 is the measurement result of the curing time of the same epoxy adhesive using the conventional method. FIG. □ Diagram 1 of the thread flea M release date notice

Claims (1)

[Claims] In measuring the curing time of an organic adhesive, the wave number region in which the transmittance or absorbance of the infrared absorption spectrum of the organic adhesive changes over time is determined, and the transmittance or absorbance of the infrared absorption spectrum in the wave number changing region is determined. A method for measuring the curing time of an organic adhesive, characterized by measuring the curing time of the organic adhesive based on the relationship between the change in the temperature and the elapsed time.