Biopolymers
Functional Polymer Systems
Synthesis and Polymer Technology
Water-born Polymer Systems
Pilot Plant Center Schkopau
Material development based on amino resins
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Contact Dr. Frank Börner Phone +49 331 568-1221 Fax +49 331 568-2610 e-mail frank.boerner@iap.fraunhofer.de |
Amino resins are already used for a long time because of their good cost/performance-ratio. Melamine resins with their excellent properties
are the mostly applied amino resins. Melamine resin compounds with inorganic as well as organic filler or reinforcing materials are track
resistant and hardly combustible. They are characterized by good thermostability and well-balanced mechanical properties. Melamine resins
are particularly applied in the field of wood laminating and as components for furnace-hardened varnish due to their superior surface
properties (hardness, brightness). Other applications include wet-strength finishing of paper, the use as textile auxiliary, the gluing of
particle boards, in moulding compounds and laminates. Melamine resins are also used as a wall material for microencapsulation purposes.
Melt processable melamine resins
Commercially available melamine resins are mainly both provided and processed as aqueous solutions. Non-etherified solid resins are commercially available as spray dried powders. But also in this case the solid resins have to be diluted before application. The processing must be carried out in solution because the resins are cured during melting. Thermoplastically processable moulding compounds are commercially available with organic and inorganic fillers. The resins are more stable and are cured at higher temperatures due to a partially etherification. One drawback is their liquid state at room temperature and the high stickiness.
An etherified resin was developed by reactive extrusion which can be processed without additional fillers from the melt. Methylol and ether groups were splitted off by short heat treatment. As a result water, acting as a barrier layer in the production of laminated composites, couldn´t be produced during curing. Therefore the resin melt is characterized by excellent penetration properties in the compounding/lamination process. Table 1 shows mechanical data of sheets produced with a meltable melamine resin.
Commercially available melamine resins are mainly both provided and processed as aqueous solutions. Non-etherified solid resins are commercially available as spray dried powders. But also in this case the solid resins have to be diluted before application. The processing must be carried out in solution because the resins are cured during melting. Thermoplastically processable moulding compounds are commercially available with organic and inorganic fillers. The resins are more stable and are cured at higher temperatures due to a partially etherification. One drawback is their liquid state at room temperature and the high stickiness.
An etherified resin was developed by reactive extrusion which can be processed without additional fillers from the melt. Methylol and ether groups were splitted off by short heat treatment. As a result water, acting as a barrier layer in the production of laminated composites, couldn´t be produced during curing. Therefore the resin melt is characterized by excellent penetration properties in the compounding/lamination process. Table 1 shows mechanical data of sheets produced with a meltable melamine resin.
| Tensile strenght [MPa] |
Young´s modulus [GPa] |
Elongation at break [kJ/m2] |
|
| Carbon fiber laminatet | 410 | 8.7 | 1400 |
| Laminate of regenerated cellulose | 119 | 8 | 310 |
Table 1. Mechanical parameters of laminated composites, produced with a meltable melamine resin
Melamine resin foams
Normally melamine resins form rigid and brittle materials during hardening. But there is also a flexible open-cell melamine resin foam on the market, resulting from a special production process (BASOTECT foam produced by BASF). The drawback in many potential application fields for the BASOTECT foam is the high ability to absorb water like a sponge.
At Fraunhofer IAP a melamine resin foam with water-repellent properties was developed and patented. Hydrophobic melamine resin foams could be produced combining nanoparticles with meltable melamine resins. The new developed foams are water-repellent even after mechanical treatment, e.g. sawing, polishing, milling or crushing.
The thermal conductivity is equivalent to rigid-foam sheets, applied in the building area. The new developed foam has a comparable high pressure resistance (Table 2). The foam can be prepared without any organic solvent which is an outstanding advantage. He is incombustable and, compared to sheets made of styrodur, unmeltable.
| Thermal conductivity (W/m2K) |
Pressure resistance (MPa) |
Density (g/cm3) |
|
| Melamin resin foam | 0.038 - 0.040 | 0.8 | 0.08 - 0.11 |
| Styrodur | 0.032 - 0.050 | 0.2 - 0.7 | 0.025 - 0.065 |
Table 2. Specific values of commercial and newly developed expanded plastic slabs.
Application and services
Based on the amino resin synthesis and application know-how at the Fraunhofer IAP we are offering research and development capacities for material development as well as the identification of new application fields for amino resins, e.g.
- Fire protection area
- Plastics industry
- Wood processing
- Textile industry
- Printing and paper industry
- Building industry
Selected patents:
F. Börner, G. Rafler
Amino resin foam free of blowing agents, production method thereof, and application thereof
EP 1808454 (2007)
E. Bonatz, H. Remde, F. Börner, G. Rafler
Thermoplastic deformable composite material and process for preparation
EP 1479722 (2002)
F. Börner, G. Rafler, E. Bonatz
Melt processable amino resin based on 1,3,5-triazines and aldehydes
DE10056398 (2000)