GB/T 2794-1995 Determination of viscosity of adhesives

This standard specifies the method for measuring the viscosity of adhesives using a rotational viscometer and a viscosity cup. The rotational viscometer method of this standard is applicable to the viscosity measurement of adhesives with Newtonian or near-Newtonian fluid properties. The viscosity cup method of this standard is applicable to the viscosity measurement of adhesives with a 50mL sample outflow time of 30 to 100 seconds. GB/T 2794-1995 Determination of adhesive viscosity GB/T2794-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination methods for viscosity of adhesives
Determination methods for viscosity of adhesives1 Subject content and scope of application
This standard specifies the method for determining the viscosity of adhesives using a rotational viscometer and a viscosity cup. GB/T 2794-—1995
Replaces GB279481
The rotational viscometer method of this standard is applicable to the determination of the viscosity of adhesives with Newtonian or nearly Newtonian fluid characteristics. The viscosity cup method of this standard is applicable to the determination of the viscosity of adhesives with a 50mL sample outflow time of 30 to 100s. 2 Principle
2.1 The viscosity measured by the rotational viscometer is the dynamic viscosity, which is based on the reversible change of the apparent viscosity with the shear rate. 2.2 The viscosity measured by the viscosity cup is the conditional viscosity, which is the viscosity expressed by the time it takes a certain volume of adhesive to flow out of a hole of a specified diameter at a certain temperature.
3 Instruments and equipment
3.1 Rotational viscometer.
3.2 Constant temperature bath: can maintain 23±0.5℃ (other temperatures can also be selected according to the requirements of the adhesive). 3.3 Thermometer: graduation is 0.1℃.
3.4 ​​Container: a container with a diameter of not less than 6cm and a height of not less than 11cm or a container attached to the rotary viscometer. 3.5 Viscosity cup: the capacity of viscosity cup No. 1~~~4 is greater than 50mL. Specifications and dimensions are shown in the figure below: Approved by the State Administration of Technical Supervision on December 20, 1995 574
Implementation on August 1, 1996
3.6 Stopwatch: accuracy is 0.2s.
3.7 Measuring cylinder: 50mL.
3.8 Constant temperature chamber: can maintain 23±0.5℃
4 Sample
4.1 The sample should be uniform and free of bubbles.
GB/T 2794---1995
$60 + 0.50
35~8:38
#45±0.05
The small holes d are:bZxz.net
d - 1. 778±0. 003
dz=2. 54±0. 003
d3=3.81±0.003
ds=6.35±0.003
Viscosity cup No. 1~4
4.2 The sample size must be able to meet the measurement needs of the rotational viscometer and viscosity cup. 5 Test steps
5.1 Rotational viscometer method:
5.1.1 For the same sample, the same rotor and speed should be selected so that the reading is within the range of 20%~~80% of the dial. 5.1.2 Place the container containing the sample in a constant temperature bath to balance the sample temperature with the test temperature and keep the sample temperature uniform. 5.1.3 Vertically immerse the rotor into the center of the sample and make the liquid level reach the rotor liquid level mark (protective frame should be installed if available). 5.1.4 Start the rotational viscometer and read the reading when the pointer does not change on the disc during rotation. 5.1.5 Measure each sample three times.
5.2 Viscosity cup method:
5.2.1 Clean the viscosity cup and dry it in the air or blow it dry with cold wind. Observe the outflow hole of the viscosity cup against the light and it should be clean. 5.2.2 Place the sample and viscosity cup in a constant temperature room to maintain a constant temperature. 5.2.3 Fix the viscosity cup and 50mL measuring cylinder vertically on the bracket, with the outflow hole 20cm away from the bottom of the measuring cylinder, and place a 50mL measuring cylinder 575
below the outflow hole of the viscosity cup.
GB/T2794—1995
5.2.4 Block the outflow hole with your hand and fill the viscosity cup with the sample. 5.2.5 Release your fingers to allow the sample to flow out. Record the time from when the finger is removed from the outflow hole to when the sample in the receiving measuring cylinder reaches 50mL, and use the outflow time (s) as the sample viscosity.
5.2.6 Make another measurement, and the difference between the two measured values ​​should not be greater than 5% of the average value. 6 Result Expression
6.1 In the rotational viscometer method, take the smallest reading value among the three sample tests and round it to three significant figures. 6.2 In the viscosity cup method, the result is expressed as the arithmetic mean and round it to three significant figures. 7 Test results
7.1 Rotational viscometer method: Calculate the reading according to the viscometer regulations and express it in Pa·s or mPa·s. 7.2 Viscosity cup method: Express it in s.
8 Test report
The test report should include the following contents:
Source, name and type of sample;
Model, rotor and speed of the rotational viscometer or the number of the viscosity cup used; test temperature,
Viscosity value.
Additional remarks:
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Shanghai Rubber Products Research Institute. This standard was drafted by Shanghai Rubber Products Research Institute. The main drafter of this standard is Xin Renfen.
This standard is equivalent to the American Society for Testing and Materials standard ASTMD10841988 "Method for Determination of Viscosity of Adhesives". 576
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