Fully-Automated Foam Sealant

Nov. 16, 2018
Sonderhoff's two-component foam sealant replaces die-cut and molded gaskets.

Formulated to conform to highly intricate metal and plastic components, Fermapor K31 is a product line of two-component, crosslinking polyurethane formed-in-place (FIP) foam sealants designed to create a barrier gasket that effectively protects electrical and electronic assemblies from moisture, dust, dirt, liquids and other contaminants. Fermapor K31 products offer dramatic cost and performance advantages over prefabricated, manually-applied cut gaskets. The technology effectively seals electrical and electronic housings, lighting enclosures, appliances, and other contaminant-sensitive consumer and industrial assemblies.

 

Two-component Fermapor K31 cures at room-temperature when its resin and hardener are mixed during the dispense process. Ovens are not required, but heat will accelerate cure. The cured gasket operates reliably in temperatures from -40 to +100°C, and can withstand up to 160°C for short durations. The material meets REACH/EC 1907/2006 and RoHS standards.

 

Once applied, Fermapor K31 expands to its full size in seconds, so process-oriented quality control systems can determine whether the seal has achieved its required height over the entire contour. The sealing foam adheres to and seals many different substrates and shapes, and provides 100% contact between mating parts. The gasket’s mixed-cell foam structure makes Fermapor K31 highly compressible, with elastic recovery between 90 and 97%, which is critical for frequently opened and closed parts such as lighting enclosures, e-box covers and switch cabinet doors. It also compensates for component tolerances.

 

While Fermapor K31 formulations can be customized for color and performance, the standard product is black. It offers a hardness from 5 shore 00 to 40 shore A, compression resistance from 5 to 200 kPa, bulk density from 0.10 to 0.60 g/cm3, tensile strength up to 2 MPa, and elongation up to 400%. Hydrophobic formulations absorb just 5 to 10% water at room temperature under compression.

 

Specific Fermapor K31 products are formulated to provide special properties such as fast cure, low-emission, FDA conformity, antimicrobial protection and flame retardancy. The fast cure formulation is highly reactive, offering tack-free time of 2 to 3 minutes for high-speed manufacturing processes. Formulated to reduce VOC emission in car interiors, low-emission Fermapor K31 meets Daimler’s delivery specification DBL 5452-13. Other formulations are specially designed to provide flame retardancy up to UL-94 HF-1; or to provide antimicrobial protection.

 

Fermapor K31 materials are applied using a two-component, low-pressure mixing and dosing system - the DM 402/403 - for fully or semi-automated FIP sealing. This system’s high process reliability meets the quality requirements of different industries and is especially suitable for three-dimensional part geometries with or without a groove. The machine’s standard output rate ranges from 0.5 to 3.0 g/sec. Customers can adjust the degree of hardness by varying material mixing ratios, and to change seal width and height by adjusting dosing output. Dynamic mixing delivers a homogenized blend of components, while a highly-rigid linear robot ensures positioning and dispensing accuracy. Remote maintenance can be completed using a modem or TCP/IP.

PropertyFERMAPOR K31Appearanceblack or grey, other colors upon requestHardnessfrom 5 Shore 00 to 40 Shore A possibleCompression load
deflection (25% compression)5 kPa to 200 kPaDensityfrom 0,1 g/cm³ to 0,6 g/cm³Temperature resistancefrom – 40° to + 100°C
(short time up to + 160°C)Tensile strengthup to 2 MPa [N/cm²]Elongation at breakup to 400%Compression set (DVR)> 97% depending on test
conditionsWater absorptionfrom < 3,5%, hydrophobic
versions availableFlame retardancyup to UL-94 HF-1 possible