BS/EN 12704-2016 pdf download.Adhesives for paper and board, packaging and disposable sanitary products
Determination of foam formation for aqueous adhesives.
This BS/EN 12704 specifies a test method to determine the foam formation, or air entrainment during rapid stirring of aqueous adhesives with a maximum viscosity of 10 000 MPa•s at room temperature determined in accordance with EN 12092.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for Its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 923, Adhesives – Terms and definitions
EN 1067, Adhesives – Examination and preparation of samples for testing
EN ISO 15605, Adhesives – Sampling (iSO 15605)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 923 apply.
4 Principle
The adhesive is stirred under defined conditions and the foam formation determined from the
differences between the initial and final volumes of the adhesive.
5 Apparatus
Specimens shall be conditioned for 24 h at 23 °C and 50 % RH.
5.1 Stirrer motor, capable of driving the stirrer at an adjustable rotary speed up to 3 000 mm-’.
5.2 Stirrer, with dimensions as shown in Figure 1.
5.3 Beaker, 2 I, of transparent material of approximately dimensions, h = 230 mm, d = 105 mm.
5.4 Balance, accuracy ± 1,0 g.
5.5 Mechanical system, to secure the stirrer and beaker.
5.6 Timer, accuracy ± 1 s.
5.7 Ruler, accuracy ± 1 mm.
6 Procedure
6.1 Take the sample in accordance with EN ISO 15605 and prepare the sample in accordance with
EN 1067,
Weigh (400 ± 10) g directly into the clean beaker (5.3).
6.2 Position the stirrer (5.2) in the beaker so that it is approximately 1 mm from the bottom and the shaft of the stirrer is in the centre of the beaker, (±1,00 mm).
6.3 Measure the initial height h (in millimetres) of the adhesive in the beaker.
6.4 Begin stirring slowly and increase to 2 500 min’ over lOs.
6.5 Start the timer (5.6) and continue stirring for S mm.
6.6 Stop stirring and immediately measure the final max height h1 (in millimetres) of the adhesive in the beaker.
6,7 Measure the height of the adhesive also after I mm and 5 mm.
6.8 Carry on minimum of 3 tests, each test consisting of three measurements of adhesive height after stirring (immediately, 1 mm and 5 mm), as described in 6.6 and 6.7.
NOTE Comparison of the values of adhesive height taken immediately after stirring, after 1 mm and after 5 mm are an indication of foam stability. Faster decrease in foam height with time means worse foam stability.
7 Expression of results
Calculate the Foam Formation, f as a percentage, calculated from the difference In height of the adhesive before and after stirring, using the following equation:
f(%) h1 h, xlOO (1)
where
h1 Final height of adhesive after stirring, in
millimetres;
h initial height of adhesive before stirring, in
mill i metres;
f(%) foam formation (as %).
In each test, calculate the foam formation as the arithmetic mean of the results of the three measurements of adhesive height carried out immediately after stirring, after 1 mm and after 5 mm. Express final value of Foam Formation obtained in the last three tests.
8 Test report
Test report shall include:
a) a reference to this European Standard;
b) identification of the adhesive, giving all information for the sample;
c) description of the adhesive (i.e. chemical type, pH, viscosity);
d) number of tests carried out;
e) foam formation;
f) date of test.BS/EN 12704-2016 pdf download.