Matti Kärkkäinen. (1986). Koivuvaneritukkien ja -runkojen arvosuhteet. Silva Fennica vol. 20 no. 1 article id 5261. https://doi.org/10.14214/sf.a15440

English title: Value relations of birch veneer logs and stems in Finland.

Original keywords: koivu; järeys; vaneri; mallinnus; koivuvaneritukki; viilun sorvaus; puustamaksukyky

English keywords: Betula pendula; Betula pubescens; simulation; plywood; log size; birch veneer; veneer logs; value of raw material

Abstract | View details | Full text in PDF | Author Info

A model was developed in order to describe the peeling of veneer for determining value relationship for birch veneer logs and stems. The model was based on selling prices of veneer and other products as well as processing costs. The model was utilized for determining the effect of various input variables on the log value.

According to the results, the effect of tree size was important for the value of raw material. Even knottiness had an effect although only in the higher manufacturing costs of knotty veneer were taken into account. Pruning was a method to increase substantially the proportion of knotless veneer.

The PDF includes an abstract in English.

Kärkkäinen, E-mail: mk@mm.unknown

Category : Article

article id 7265, category Article

V. Pöntynen. (1931). Suomen puunjalostusteollisuuden raaka-aineen käyttö vuosina 1911-29. Acta Forestalia Fennica vol. 37 no. 3 article id 7265. https://doi.org/10.14214/aff.7265

English title: Wood consumption of wood manufacturing industry in Finland in 1911‒1929.

Original keywords: metsäteollisuus; sahateollisuus; selluteollisuus; puun käyttö; puu raaka-aine; vaneriteollisuus; puuhiomo

English keywords: forest industry; wood consumption; pulp industry; sawmilling industry; plywood industry; mechanical pulp

Abstract | View details | Full text in PDF | Author Info

The main source of data was the official industrial statistics in 1911‒1929. The data was complemented with information from other sources, and the figures converted to solid volumes under bark. The wood consumption of wood manufacturing industry in the period varied strongly, being lowest in 1918 (2.2 million m³) and highest in 1927 (18.1 million m³). The wood consumption dropped during the World War I.

The wood manufacturing industry in Finland concentrated on sawmilling industry which has used annually 70‒80% of the wood consumed in the whole wood manufacturing industry. Other sectors of industry using wood were plywood industry, wood-wool industry, spool factories, match industry, mechanical pulpwood industry and pulp industry.

The PDF includes a summary in German.

Pöntynen, E-mail: vp@mm.unknown

Category : Research article

article id 607, category Research article

Jurkka Kuusipalo. (2001). Plastic coating of plywood using extrusion technique. Silva Fennica vol. 35 no. 1 article id 607. https://doi.org/10.14214/sf.607

Keywords: plywood; thermoplastics; polymer; polyethylene; polypropylene; extrusion coating; adhesion

Abstract | View details | Full text in PDF | Author Info

The target was to study and develop industrially suitable methods to apply thermoplastic coatings on plywood. Typically, wear and climatic resistance for wooden sheets, such as chip board and plywood, is achieved by thermosetting resin coating (e.g. phenol-formaldehyde). However, economical and environmental issues are driving towards thermoplastic coatings (e.g. polyethylene) in such products. Several technologies, such as film gluing and laminating, have been introduced, but the costs and processing are limiting factors. This study concentrates on direct coating of plywood with extruded molten plastic film, in other words extrusion coating of plywood. This technique provides fast coating process and cheap raw materials. In the study it was found that extrusion coating of plywood is difficult. The high heat energy of the molten plastic causes moisture evaporation of the top veneer, and the only possible escape direction of the evaporated moisture is through the plastic, which causes bubbling in the plastic coating. Another disadvantage of the plywood is its rigidity, which limits the development of the process. In this work, a new technique was applied for coating the flexible veneers with typical extrusion coating equipment, where the escape of the evaporated moisture was possible through the top veneer to the atmosphere. Another main issue was to reach sufficient adhesion between plastic and plywood. Target was achieved using either monolayer polyethylene (PE-LD) or 2-layer polypropylene/adhesion polymer plastic coatings.

Kuusipalo, Tampere University of Technology, Institute of Paper Converting, Korkeakoulunkatu 4 C, P.O. Box 541, FIN-33720 Tampere, Finland E-mail: jurkka@cc.tut.fi

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