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38 TECHNOLOGY SEP/OCT 2024 FDM ASIA | www.fdmasia.com

Joos Mind abies (L.) H.Karst) with about three percent moisture content
(MC), intended for use in face and core layer particleboard
production (reference raw material) and obtained from the
Research and Development Centre for Wood-Based Panels

in Czarna Woda, Poland, were used.
Silekol S-123 (Silekol, Kędzierzyn—Koźle, Poland) of about
66 percent dry content (EN 827 2005) urea-formaldehyde
(UF) industrial resin was used, with ammonium nitrate water
solution as a hardener, to reach a curing time of the gluing
loop economy by enabling the high-quality reuse of critical mass in 100 °C of about 86 s).
components after the window’s useful life has ended. Guidelines The imitation post-consumer window frames were prepared
for designing wood windows focus on allowing the high-quality from pine (Pinus sylvestris L.) sawn wood in the laboratory and
recycling of major components once the window has reached then painted—with clear varnish and white paint. Two types

the end of its useful life. of wooden window surface professional finishing systems,
These guidelines recommend materials, connections, transparent and white, including acrylic primer, base, and
structural design, and component geometry to facilitate efficient face coats, delivered by international brands, were used for
and cost-effective recycling processes. surface finishing. We do not publish the provider’s name to
avoid connecting the results with the coating producer.
Aim and Preparation Following the production process for the window frames, a
Analysing the life-cycle impact of recycling various building waterproofing layer, a primer, an interlayer, and an appropriate

components and materials allows the industry to understand top-coat were applied. The application was carried out by the
the environmental benefits of reuse and recycling, thereby manufacturer’s recommendations.
supporting the adoption of sustainable construction practices. The window frames prepared this way were seasoned for
Therefore, it is crucial to keep the state of the art up to one year and then re-milled using a laboratory knife milling
date, given the rapid growth of the wood coatings industry. machine. This laboratory prototype was provided by the
This fast-paced development necessitates continuous research Research and Development Centre for Wood-Based Panels
and innovation. in Czarna Woda, Poland, and equipped with knives and
While shredding window frames may appear to be a counter-knives similar to those in industrial milling machines
straightforward solution for recycling, scientific reports highlight used for particleboard production.

numerous challenges, mainly due to the variety of grades and During the particles’ resination, the glue was sprayed over
coatings present. the particles with an air gun while they were being blended in
This research aims to identify the key factors that limit a laboratory mixer. The following resination was applied: 12
the recycling of window frames to produce three-layer percent and 10 percent, face and core layer, respectively. No
particleboards by conducting studies under fully controlled hydrophobic agents were added. The panels had a nominal
conditions, where the raw materials, processes, and coatings density of 670 kg m−3, were 16 mm thick, and 32 percent
are precisely known—factors that typically complicate the of the mass was from the face layers.

recycling of such materials. The share of post-consumer particles was 5, 10, 25, 50,
Industrial particles, pine (Pinus sylvestris L.) and spruce (Picea and 100 parts by weight. The manually formed mats were