GB/T 7123.1-2015 English PDF (GBT7123.1-2015)

This Part of GB/T 7123 specifies the method for determination of the working life of multi-component adhesives. This Part applies to the determination of the working time of multi-component adhesives.

GB/T 7123.1-2015
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 83.180
G 38
Replacing GB/T 7123.1-2002
Determination of the working life of multi-component
adhesives
[ISO 10364:2007, Structural adhesives - determination of the pot life
(working life) of multi-component adhesives, MOD]
ISSUED ON: DECEMBER 31, 2015
IMPLEMENTED ON: JULY 01, 2016
Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the PRC;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Method classification ... 6
5 Principle ... 6
6 Instruments and equipment... 7
7 Test environment ... 8
8 Test procedure ... 8
9 Result representation ... 11
10 Test report ... 11
Determination of the working life of multi-component
adhesives
1 Scope
This Part of GB/T 7123 specifies the method for determination of the working life of multi-component adhesives.
This Part applies to the determination of the working time of multi-component adhesives.
2 Normative references
The following documents are indispensable for the application of this document. For the dated references, only the editions with the dates indicated are applicable to this document. For the undated references, the latest edition (including all the amendments) are applicable to this document.
GB/T 2790 Adhesives, 180° peel strength test method for a flexible-bonded- to-rigid test specimen assembly (GB/T 2790-1995, ISO 8510-2:1990, EQV)
GB/T 2791 Adhesives, T peel strength test method for a flexible-to-flexible test specimen assembly
GB/T 2794-2013 Determination for viscosity of adhesives - Single cylinder rotational viscometer method
GB/T 2943 Terms of adhesive
GB/T 7124 Adhesives - Determination of tensile lap-shear strength of rigid- to-rigid bonded assemblies (GB/T 7124-2008, ISO 4587:2003, IDT)
GB/T 20740 Adhesive - Sampling (GB/T 20740-2006, ISO 15605:2000, IDT)
3 Terms and definitions
The terms and definitions defined in GB/T 2943 and the following apply to this document.
3.1
Working life
determine the working life of the adhesive.
Method 6 - Bonding strength method: By measuring the time required for the adhesive bonding strength to drop to a specified value or a specified ratio, determine the working life of the adhesive. This method is not suitable for adhesives whose working life is less than 5 min.
6 Instruments and equipment
6.1 Balance: Method 1, Method 2, Method 5 and Method 6 require the weighing range of the balance to reach (500±0.2)g. Method 3 and Method 4 require the weighing range of the balance to reach (100±0.2)g.
6.2 Beaker: The material does not react with the test adhesive. The wall thickness does not exceed 1 mm. Method 1 and Method 6 require a beaker
capacity of 400 mL. Method 3 requires a beaker capacity of 250 mL. Method 4 requires a beaker capacity of 50 mL. Method 5 requires a beaker capacity of 50 mL and 200 mL.
6.3 Scraper: The material does not react with the test adhesive. The end surface is flat.
6.4 Rotational viscometer: In accordance with the requirements of GB/T 2794- 2013.
6.5 Water bath: In the temperature range of 15 °C~30 °C, Method 2, Method 3 and Method 4 require the temperature to be constant at ±0.1 °C. Method 5 requires the temperature to be constant at ±0.2 °C.
6.6 Stopwatch: Accurate to within ±1 s.
6.7 Disposable plastic pipe: 47 mm in inner diameter and 210 mm in length. It can be connected with threaded pipe fittings and pistons. The pipes and pistons do not react with the test adhesive.
6.8 Stirring paddle: With spiral stirring blades; it does not react with the test adhesive.
6.9 Stirrer: With electric or pneumatic motor. The speed is adjustable between 0 r/min~1000 r/min.
6.10 Extrusion nozzle: The nozzle material does not react with the test adhesive. It can be connected to the front end of the disposable plastic pipe, to facilitate the uniform mixing of the components of the adhesive. The recommended
aperture is 2 mm~4 mm.
USE the time of the first viscosity test after mixing as the starting time. The test value can be considered as the beginning of the apparent viscosity change representing the chemical reaction. According to the expected working life, conduct interval testing.
Note: The number of tests and the strength of mixing and stirring have an impact on the viscosity and operating time. Therefore, during the test, the appropriate time interval, mixing and stirring speed, and rotation speed shall be selected.
The working life of the adhesive is the time between the end of mixing and reaching the specified viscosity value. In general, the specified viscosity value is twice the initial viscosity.
8.3 Method 2 - Extrusion method
Under the specified test environment, use the specified water bath to adjust each component adhesive to the specified temperature. Usually, it is (23±2)°C. According to the manufacturer's instructions, prepare the adhesive specimen. Directly weigh the specimen into a disposable plastic pipe; USE a suitable mixer to mix it thoroughly. MIX (60±10)s at a mixing speed of (600±100)r/min. The recommended mixing amount is 200 g.
Quickly remove the seal on the threaded end of the round pipe; SCREW on the extrusion nozzle and push in the piston; PUT the pipe into the extrusion gun. Quickly set the required extrusion pressure.
Through a static mixer, quickly squeeze a certain amount of adhesive into the weighing aluminum pan, to exhaust the air in the pipe and the unmixed
adhesive at the end.
TURN on the stopwatch; at the set pressure, within a specific period of time, squeeze the newly mixed adhesive into the aluminum pan; WEIGH the
aluminum pan; RECORD the mass of the extruded adhesive.
At appropriate intervals, repeat the above steps, until the amount of extruded adhesive drops to an agreed amount. The time between turning on the
stopwatch and reaching the agreed amount is the working life.
8.4 Method 3 - Spreading method
In the test environment, adjust each component adhesive to the specified temperature in a water bath. Usually, it is (23±2)°C.
According to the manufacturer's instructions, mix a certain mass of adhesive in the beaker. The recommended mixing mass is 200 g.
working life.
Note: Before testing, it shall consider the heat generated by the multi-component adhesive during the curing process.
8.7 Method 6 - Bonding strength method
Under the test temperature of (23±2)°C, adjust all the components of the adhesive, to make the component temperature consistent with the ambient temperature. According to the proportion in the instructions for use, weigh a certain mass of the adhesive into a beaker. The recommended mixing mass is 200 g.
TURN on the stopwatch; USE a flat scraper to mix the test specimen for
(60±10)s. It shall make sure that, the specimens at the bottom and the edge areas of the beaker are mixed thoroughly.
The tensile lap-shear strength and peel strength can be in accordance with the requirements of GB/T 7124, GB/T 2790 and GB/T 2791, respectively.
When preparing the specimen, apply glue according to the manufacturer's instructions.
Determine the bonding strength of the newly prepared adhesive respectively; the bonding strength measured after an appropriate time interval. The selected time interval shall be recorded in the test report.
Note: The choice of time interval refers to the working life specified by the adhesive manufacturer.
The working life is the time from just preparing the adhesive until the bonding strength is less than the predetermined value or percentage.
9 Result representation
The working life of the adhesive is expressed in hours (h) or minutes (min). USE the average of at least three measured values as the determination result. 10 Test report
The test report shall include the following:
a) Number and method of the test basis standard (i.e. this Standard);
b) Specimen source, name, type and quantity;