The detection of the adhesive applicable period
Time：2012-10-27 11:25:44 Hits：1531
Applicable period is also referred to as a time period or may be used, i.e., after preparation of the adhesive can maintain its availability time. The pot life is a chemical reaction adhesives and double-liquid type rubber adhesive process indicators for the preparation of adhesives and construction time of great guiding significance.
First, the Principle of Measurement
The chemical reaction type adhesives generally dissipates heat in a mixed-up, its viscosity significant growth to the gel, this time is the adhesive applicable period.
Second, the instrument
(1) constant temperature water bath: temperature fluctuation is less than ± 2 ℃.
(2) rotational viscometer.
(3) Balance: 0.1 g.
Third, the steps
(1) placed on the respective components of the adhesive under test (23 ± 2) ° C test temperature, at least parked 4 h.
(2) In 1/3 volume ratio with glue large beaker adhesive formulated manual preparation of not less than 250 mL of adhesives, adhesives applicable period after the timing of the various components are thoroughly mixed, as the start timing.
(3) the preparation of a good adhesive, as quickly as possible, are divided into several parts (not less than 5 parts), and stored in a 60-mL lidded container, at least filled with a container volume of 3/4. The adhesive sample for each of the containers in the determination of a viscosity value, and preparing a set of glued specimens. The glued sample preparation adhesives manual requirements.
(4) from the applicable period starting moment onwards, the intensity measurement of the viscosity and glued be repeated after a certain time interval.
(5) When the adhesive initial viscosity or have a bonding strength could not be measured, allowing only make a single determination.
Adhesives applicable period determined
After the test, the viscosity of adhesives and adhesive bonding strength was plotted against time, down to a short period of time in the time following the index value determined as the period of application of the adhesive to the rapid viscosity mutation increased the time and the bonding strength. For heat release adhesive is mixed, its mixture is generally preferably to 25 g. Put less heat, solvent-based adhesive approximate the applicable period of about 8 h, the mixture amount of 500 mL is appropriate.
The test results are expressed in hours (h) or the stars (min).
