The POROLUX™ 100 series uses the pressure scan method. As this method is fast and typically generates very reproducible results, the POROLUX™ 100 series is regarded as being extremely suited for QC type of work.
A special version of the POROLUX™ 100 is available for materials with large pores such as of textiles and non-wovens.
|Max pressure||0.15 MPa/ 22 psi|
|Min pore||0.427 µm|
|Max pore||500 µm|
|Max flow||200 l/min|
|Sample holders||25 mm|
|Pressure sensors||2 bar/ 29 psi|
|Flow sensors||10-200 l/min|
|Service via internet||Yes|
Nonwovens, fibrous materials and textiles.
ASSESMENT OF NON-WOVEN MATERIALS BY CAPILLARY FLOW POROMETRY
The term non-woven refers to products made by processes that do not include weaving nor knitting (ASTM D1117-80). The fibers in these materials are bonded together by chemical, mechanical, heat or solvent treatment. Non-woven materials are used in applications in different sectors (filtration, automotive, construction, aeronautical, food and medical, amongst other). In 2013 the US nonwoven fabric industry market accounted for $5.4 billion and the demand for nonwovens is forecast to rise 5.7% per year to $7.1 billion in 2016.
As for every material, an in depth characterisation of the structure of non-wovens is essential in order to understand better and improve their performance for a given application.
Capillary Flow Porometry (CFP) measures pore size and pore size distribution of through pores with good accuracy and reproducibility in one individual and fast measurement. The technique is based on the displacement of an inert and nontoxic wetting liquid embedded in the porous network of a material by applying an inert pressurised gas (e.g. nitrogen). The larger pores become empty first and, as the applied pressure increases, so do the smaller ones until all through pores are empty. The gas flow through the sample against the pressure applied is measured. The pressure required to empty pores of a certain diameter is used to calculate the pore size accordingly to the Young–Laplace formula P=4*cos (θ)*γ/D, where (P) is the pressure required to displace the liquid from the pore, θ is the contact angle of the wetting fluid with the material, (γ) the surface tension of the wetting liquid and (D) is the pore diameter.
APPLICATION TO NON-WOVEN MATERIALS
CFP measurements of melt blown and spun bound materials, were carried out by using a POROLUXTM 100NW porometer from POROMETER nv (right pictured). The POROLUXTM 100NW is specially designed for non-woven characterisation and it is based on the pressure scan method (the increasing pressure and the resulting gas flow are measured continuously during a test). The method is fast and typically generates very reproducible results, which makes the POROLUX™ 100NW very suited for quality control.
The maximum operating pressure of the device is 1.5 bars (22 psi), which permits measring pore sizes between 0.427 µm and 500 µm. The determination of the first bubble point (FBP), or maximum pore size, is based on the test method described in the standard ASTM F 316-03. The FBP is defined “at the pressure required to blow the first continuous bubbles detectable by their rise through a layer of liquid covering the filter”. Since the concept of the first continuous bubbles is subjective. In consequence, a unique universal criteria to calculate the bubble point does not exist.
The POROLUXTM 100NW permits selecting settings accordingly to different criteria traditionally used for FBP calculations. Options include the calculation the FBP at the pressure that corresponds to a flow rate of 30, 50, 100 ml/min, or taking the pressure at which the first measureable flow is detected by the equipment, amongst other. The choice of one method or another is always the ultimate decision of the user.
The criteria selected for calculating the FBP was the pressure at which the first flow was measured. For very porous samples, like non-woven materials, it is recommended choosing “first flow” or “FBP above a certain flow value” because it is not always easy to calculate the FPB at one specific flow value (e.g. 30ml/min). In each measurement, a total of 30 data points were taken in the pressure range from 0- 100 mbar. Three replicates for each sample were measured. The FBP, mean flow pore (MFP) and smallest pore size (SP) of sample “A” (spunbond type material) and “B” (meltblown type material) are given below:
|Sample A||Average (µm)||Std (µm)||RSD (%)||Sample B||Average (µm)||Std (µm)||RSD (%)|
The gas flow against the applied pressure on the dry sample is also carried out (dry curve). The half-dry curve is obtained by dividing the flow values of the dry curve by 2. The MFP is calculated at the pressure where the wet and the half-dry curves meet. It corresponds to the size at which 50 % of the total gas flow can be accounted. The SP corresponds to the pressure where the wet and the dry curves meet. Due to the nature of the calculation of the MFP and the SP these have normally a higher standard deviation than FBP values. As example, the wet, dry and half dry curves for sample “A” are shown below. The rounded shape of the dry curves (dotted lines) is typical of non-woven materials.
The gas flow through the sample is used to calculate the cumulative filter flow distribution against the pore size (percentage of the total flow which corresponds to pores of a certain size and larger) and the differential filter flow (increase in flow rate per unit increase in pore diameter, commonly defined as pore size distribution). The resullts for sample B are shown in the following graphic.
Overall, CFP has proven to be a very useful tool for the non-wovens characterisation industry. If you wish to know more about how CFP can help your non-woven business, contact us at firstname.lastname@example.org.
|LIQ100||Basic liquid Permeability Extension Kit Porolux 100/500 - 6 liter vessel, external sample holder 25mm||PRICE|
|USH||Universal sample holder||PRICE|
|CONKLOW||Low pressure connection kit Porolux 3 m hose and filter/regultor - comes std with P1000, option for P100x||PRICE|
|POREFIL250||250 ml. Porefil wetting fluid||PRICE|
|POREFIL1000||1000 ml. Porefil wetting fluid||PRICE|
|GALPORE250||250 ml. Galpore wetting fluid||PRICE|
|SILPORE250||250 ml. Silpore wetting fluid||PRICE|
|REF1UMC||1,0 µm pore size control sample (100 pc.) + certificate of conformity||PRICE|
|SWUPDATE||General Software Update (including - if necessary - PLC + GUI)||PRICE|
|SWLANG||Laguage pack 1 extra language (German, Sapanish, Chinese or Russian)||PRICE|
|SWEXTFLOW||Extended flow data (CFF) software function (pressure at e.g. 5, 10, 80, 90% flow)||PRICE|
|SWLARGEVOL||Large volumes Software function||PRICE|
|MANUAL||1 Extra printed manual EN/DE/RU/ES||PRICE|
|EX10047||Exchange Sample holder Porolux 100 47 mm (instead of SH 25mm)||PRICE|
|EX10013||Exchange Sample holder Porolux 100 13 mm (instead of SH 25mm)||PRICE|
|SH13EXT||Sample Holder complete 13 mm (on external table and extension hose)||PRICE|
|SH25EXT||Sample Holder complete 25 mm (on external table with extension hose)||PRICE|
|SH47EXT||Sample Holder complete 47 mm (on external table with extension hose)||PRICE|
|SHUNIV25EXT||Universal sample holder 2-10 mm samples 25 mm (on external table with extension hose)||PRICE|
|SHHF||Sample Holder complete for hollow fibers (incl 5 sealant rings)||PRICE|
|SHHFBCS||Bottom connector for hollow fiber sample holder, bore < 3mm (pkg of 10)||PRICE|
|SHHFBCL||Bottom connector for hollow fiber sample holder, bore > 3mm (pkg of 10)||PRICE|
|SH13TOP||Upper Part Sample holder 13 mm||PRICE|
|SH13BOT||Bottom Part Sample Holder 13 mm||PRICE|
|SH13CAP||Cap Screw Sample Holder 13 mm||PRICE|
|SH25TOP||Upper Part Sample holder 25 mm||PRICE|
|SH25BOT||Bottom Part Sample Holder 25 mm||PRICE|
|SH25CAP||Cap Screw Sample Holder 25 mm||PRICE|
|SH47TOP||Upper Part Sample holder 13 mm||PRICE|
|SH47BOT||Bottom Part Sample Holder 13 mm||PRICE|
|SH47CAP||Cap Screw Sample Holder 13 mm||PRICE|
|SH13METS||Metal support set Sample Holder 13 mm, 1 grid / 1 support||PRICE|
|SH25METS||Metal support set Sample Holder 25 mm, 1 grid / 1 support||PRICE|
|SH47METS||Metal support set Sample Holder 47 mm, 1 grid / 1 support||PRICE|
|SH13METS300m||Metal support plate 300µm stainless steel etched diameter 13 mm||PRICE|
|SH25METS300m||Metal support plate 300µm stainless steel etched diameter 25 mm||PRICE|
|SH47METS300m||Metal support plate 300µm stainless steel etched diameter 47 mm||PRICE|
|SH13OR||O-ring Sample Holder 13 mm||PRICE|
|SH25OR||O-ring Sample Holder 25 mm||PRICE|
|SH47QR||Q-Ring Sample Holder 47 mm||PRICE|
|CLEAN||250 ml Stainless steel cleaning fluid||PRICE|
|CPR200||Compressor 8 bar - 220 l/min - 55dB(A)||PRICE|