BS/EN 17333-2-2020 pdf download.Characterisation of one component foam Part 2 : Expansion characteristics.
— Method I — Dimensional stability: This test method describes how to determine the dimensional stability (shrinkage or expansion) of cured foam under typical and extreme conditions.
— Method 2 – Curing pressure: This method describes how to determine the generation of pressure during the curing process of an OCF.
— Method 3 — Post expansion: This method describes how to measure the expansion of a dispensed froth during the curing phase.
2 Normative references
The following documents are referred to in the text In such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 312. Particlehoards – Specifications
EN 923, Adhesives – Terms and definitions
EN 15006, Metal aerosol containers – Aluminium containers- Dimensions of the 25,4 mm aperture
EN 14847, Aerosol containers – Tinpiate containers – Dimensions of the 25,4 mm aperture
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 923 and the following apply. ISO and IEC maintain terminological databases for use In standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.orE)obp/ui
— IEC Electropedia: available at http://www.electropedia.org/
3.1
one component foam
(OCF)
moisture curing or water drying foam as well as self-curing activatable foam dispensed from a single pressurised foam container
3.2
pressurised foam container
pressunsed can according to EN 14847 and EN 15006
3.6
fully cured or dried foam
cross-linked foam which reaches its serviceable properties as claimed by the manufacturer
3.7
froth
uncured, freshly dispended foam
3.8
curing pressure
pressure build-up within the dispensed froth during curing phase
3.9
post expansion
increase of the dispensed froth volume during the curing phase
3.10
straw foam
one component or two component foam for the extrusion with an adapter tube
3.11
gun foam
one component foam for the extrusion with a foam application gun
4 Test methods
4.1 Method 1 – Dimensional stability
4.1.1 Principle
The foam is dispensed in the gap between two particle boards. When foam is fully cured, the dimensional stability of the foam is determined by measurement of the distance between the panels over several days and weeks.
NOTE Typically OCFs tend to shrink within the first few days after curing due to gas release from the closed cells. The vanishing propellant leaves an under-pressure in the cells resulting in a shrinking of cell size, therefore the whole foam shrinks. This effect is usually compensated over several days by the slower permeation of air.
Shrinking foam can affect the sealing of joints by separation from the surfaces or deformation of the joints. The degree of shrinkage depends not only on the OCF formulation, but also on the environmental conditions e.g. humidity and/or temperature.
4.1.2.1 Two P3 or PS particle boards (compliant with EN 312) with dimensions of
200 mm x 100 mm x 10 mm (length x width x thickness).
4.1.2.2 2 spacers, not water absorbing, not adherent (e.g. polyethylene (PE), polytetrafluoroethylene (PTFE). on which polyurethane (PU) does not adhere), thickness 20 mm, length 90 mm.
4.1.2.3 2 screw clamps.
Further tools:
4.1.2.4 Sharp and clean knife blade.
4.1.2.5 Vernier caliper, with an accuracy of 0,1 mm.
4.1.2.6 Conditioning chamber capable of being controlled at the required temperature and relative humidity (RH) given in Table 1 and Table 2.
4.1.2.7 Water bath.
4.1.3 Sampling
4.1.3.1 CondItioning
Bring the test container to the test temperature for at least 24 h.
The particle boards shall be stored at test conditions L(23 ± 2) °C and (50 ± 5) % RH] for at least 1 week
4.1.3.2 Test pieces
One setup consists of two plates and two spacers (see Figure 2). Marks are put on the particle boards (see Figure 1). At these marks the width will be measured (four reading points per joint).
4.1.4 Test procedure
4.1.4.1 General
It is necessary to carry out at least three measurements to obtain a statistically relevant mean value.
When pre-moistening is required, the particle boards are wetted abundantly (see 4.1.4.2).
Sell-curing activatable foams don’t require moistened substrates (see 4.1.4.5).
4.1.4.2 AssemblIng
The particle board pieces and spacers are put together as follows:BS/EN 17333-2-2020 pdf download.