Phenol-formaldehyde-resin treatment of Scots pine sapwood for the reduction of resin exudation through coatings

Figures & data

Table 1. Weight gain (± standard deviation) and resin penetration of PF-treated wood.

Treatment		Weight gain (%)	Resin penetration (mm)
A	Preheating at 130°C and soaking in pure PF	6.0 ± 1.4	1–3
B	Preheating at 130°C and soaking in PF diluted with methanol 1:1	11.5 ± 4.0	2–5
C	Preheating at 160°C and soaking in pure PF	6.0 ± 0.8	1–3

Figure 1. Treated (left) and untreated reference (right) specimens after accelerated aging: (a) treatment A, (b) treatment B, and (c) treatment C.

Table 2. Colour measurements after accelerated weathering test of painted specimens treated with PF resin (treatments A, B and C) and untreated specimens (reference).

Treatment	Area without knots			Areas with knots			ΔE*
	L*	a*	b*	L*	a*	b*
A	95.2 ± 0.6	0.0 ± 0.7	2.4 ± 0.4	91.9 ± 1.8	0.1 ± 0.6	7.2 ± 1.9	5.9 ± 2.6
Reference to A	96.1 ± 0.3	−0.2 ± 0.7	2.4 ± 0.2	84.0 ± 2.8	3.8 ± 1.0	16.7 ± 1.5	19.2 ± 3.2
B	94.7 ± 0.9	−0.7 ± 0.1	2.2 ± 0.2	90.7 ± 0.8	0.1 ± 0.4	7.3 ± 1.2	6.5 ± 1.8
Reference to B	95.8 ± 0.1	−0.6 ± 0.0	2.2 ± 0.2	84.0 ± 2.1	3.7 ± 0,5	16.5 ± 0.3	19.1 ± 1.7
C	94.9 ± 0.5	−0.8 ± 0.0	1.8 ± 0.2	93.5 ± 0.5	−0.5 ± 0.2	5.1 ± 0.6	3.6 ± 0.8
Reference to C	96.4 ± 0.1	−0.6 ± 0.0	2.3 ± 0.3	83.7 ± 3.6	3.9 ± 1.6	16.5 ± 2.4	19.6 ± 4.6