Formulations and products

Following are guiding formulations for coatings on MDF and metal. The Uracross P3125/P3307 resin combination is very suitable for wood based substrates. The Uracross P3125/P3898 combination gives a very good result on metal substrates. Also combinations of Uracross P3307 and P3898 are described

Materials:

• Resin (DSM Coating Resins)
  Uracross P3125: maleate / fumarate unsatured polyester
  Uracross P3307: vinylether polyurethane resin
  Uracross P3898: vinylether polyurethane resin
• Photoinitiator (CIBA)
  Irgacure 2959 (a): 4-(2-hydroxyethoxyl)phenyl-(2-hydroxy-2-methylpropyl)ketone
  Irgacure 819 (b): phenylbis (2,4,6-trimethylbenzoyl)-phosphine oxide
• Flow control agents
  Byk 361 (c) (Byk-Cera)
  Resiflow PV 5 (Worlee) and Worlee Add 902 (Worlee): ratio 2/1 (wt%) (d)
• Pigments (Kronos)
  Kronos 2160 (e) (TiO2)
• Texture additive (Byk-Cera)
  Ceraflour 969 (f)
• Gloss reduction additives
  Ceraflour 950 (Byk-Cera) and Deuteron MK (Deuteron GmbH) ratio 1/1 (wt%)

The notes ( ) refer to the materials used in the formulations.

The Uracross P3125 and Uracross P3307 combination has been specially designed for composite woods like Medium Density Fiberboard (MDF). This binder system has a melt temperature of 100°C. The Uracross P 3125/3307 system gives a clear coating with properties comparable to conventional solvent borne urethane acrylate (see table 12). Detailed information including formulations can also be found on the Product Data Sheets:

PDS - Uracross P 3125

PDS - Uracross P 3307

Table 3 presents the guiding formulations for clear, pigmented, semi-gloss and textured coatings on MDF. These are guiding formulations and can be optimized by the formulator.
Please note the fixed ratio in which P3125 and P3307 are applied in these formulations: 83:17(wt%).

Table 3: Composition of coatings for MDF

The curing conditions of coatings for MDF are presented in table 4.

Table 4: Curing conditions for MDF

Table 5 presents coating properties which are obtained with formulations described in table 3 and curing conditions described in table 4 at a layer thickness of approximately 100 µm.

Table 5: Coating properties on MDF

The Uracross P3125 and Uracross P3898 combination gives a flexible coating with good adhesion to metal substrates like plain aluminum or steel. The solvent resistance and flow is better than traditional thermoset powders. The melt temperature is 120°C.
Formulations for clear-, and pigmented coatings are presented in table 6.

Table 6: Composition of metal coating

The curing conditions for above mentioned formulations are presented in table 7.

Table 7: Curing conditions for coatings on metal

The properties of clear-, and pigmented coatings are presented in table 8.

Table 8: Coating properties for coatings on metal

The combination of Uracross P3307 and Uracross P3898 allows adjusting the flexibility and hardness of the UV powder coating in between the properties of the individual binders.
Table 9 presents guiding formulations for different ratios P3125/P3307/P3898 for clear coatings.

Table 9: Different compositions for P3307/P3898 (clear coatings)

The obtained coating properties, for the different ratios as described in table 9, are presented in table 10.

Table 10: Coating properties for P3307/3898 (clear coating)

The curing conditions for these coatings are the same as with the other clear coatings (table 11). Different photoinitiators and UV-lamps can cure coatings with up to 25% pigment, in layer thicknesses of approximately 100µm.

Table 11: Curing conditions for P3307+P3898

The following table (table 12) presents coating properties for different coating systems. These are properties of clear coatings on MDF.

Table 12: Comparison of the coating properties of clear conventional coatings and the UV curable powder coating on MDF.