How to test the shelf life of adhesive?

This method is based on GB7751-87 Determination of storage life of adhesives.

1. Principle

The storage period of the adhesive can be tested by changing the viscosity and bonding strength of the adhesive before and after storage.

2. Instruments and equipment

Electric blast constant temperature Drying Oven, temperature fluctuation range ±2°C; Rotational Viscometer, any type of rotor viscometer; Tensile Testing Machine; constant temperature bath, temperature fluctuation range ±2°C; pharmaceutical balance, division value 0.1g; container, Covered glass bottles, plastic bottles or galvanized iron cans, or other containers agreed by both parties; special fixtures for bonding.

3. Test steps

The storage condition of the sample is (23±2)°C, and the time shall be agreed upon by both parties. Other storage conditions such as other temperatures agreed upon by the supplier and the purchaser,

The storage period test should be carried out under the conditions of standard temperature (23±2)°C and humidity (50±5)%. Adhesives that are not sensitive to moisture may be relaxed. The test is carried out as follows.

(1) Store the sample under the standard test conditions or the conditions specified in the material standard.

(2) One of the subpackaged samples was pretreated for 4 hours under standard test conditions.

(3) Mix glue according to the instructions for use of the adhesive or technical standards, prepare the bond strength test piece, and carry out the strength test according to the viscosity and corresponding strength test method in GB 2794-81.

(4) During the storage period, take samples of the subpackaged samples according to the specified time intervals, and conduct viscosity and strength tests.

4. Result evaluation

The maximum storage time for the adhesive to maintain its operability and specified bonding strength is the limit value of the storage period, and the time unit can be expressed in years, months or days.

5. Influencing factors

This force method is equivalent to ASTMD1337-5-6 (R1984) "Test method for determining the shelf life of adhesives by consistency and bonding strength". The samples should be mixed carefully and homogeneously during the test.