Plywood Production Research Articles

Flour fillers with urea-formaldehyde resin in plywood

Various flours were added as fillers for urea-formaldehyde (UF) resin, and effects on the rheological behavior and the curing properties of the resin were evaluated. The plywood properties such as bonding quality, bending strength, modulus of elasticity, and formaldehyde-release were tested. Five types of flours were used, i.e., rye flour, hemp flour, coconut flour, rice flour, and pumpkin flour. The type of flour had a major influence on the properties of resin mixture such as gel time, solid content, and viscosity. The use of rye and pumpkin flour resulted in a longer gelling time, and the adhesive mixture filled with rice flour did not attain the desired viscosity value needed for the production of plywood. The best mechanical properties and bonding quality were achieved by addition of pumpkin flour. However, the bonding quality of plywood glued with an adhesive filled with every other flour retained good values exceeding 1 N/mm2 as required by the standard EN 314-2 (1993). The use of hemp flour as a filler for UF resin led to a substantial decrease of free formaldehyde content.

Accelerated Aging of WPCs Based on Polypropylene and Plywood Production Residues

Abstract A lot of researchers are closely connected with natural, lignocellulose fibre containing bio-composites producing and studies. Various of polymer matrices, mainly polyolefins, combinations with natural fibres as a reinforcement are used. Our studies are focused on polypropylene based bio-composites containing birch plywood production by-product sanding dust (PSD) accelerated weathering processes. The nine groups of the samples with different composition were exposed in an accelerated weathering chamber for a total duration of the 1032 h. The surface colour, gloss, whiteness degree, micro-hardness and the tensile properties of the samples during the weathering were tested. In addition, the weathered surfaces were characterized by scanning electron microscopy (SEM) studies and by differential scanning calorimetry (DSC) investigations. The obtained results showed the following sight: after the weathering the surface of all samples is faded, also the changes of the gloss and of the whiteness degree occurs, but microhardness of the surface of specimens has decreased. The tensile strength of the samples changes a little, in the same time the tensile modulus increases significantly due to the decrease of the deformation ability of the polypropylene matrix and recrystallization processes in PP. The SEM images taken at the 100 and 500 times of the magnification revealed a lot of the different shape and sizes cracks on the surface of the weathered samples. DSC measurements showed the increase of the degree of crystallinity of the polypropylene after the weathering due to the recrystallization process in the polypropylene matrix.

Life Cycle Assessment of Plywood Manufacturing Process in China.

Life cycle assessment (LCA) has been an important issue in the development of a circular economy. LCA is used to identify environmental impacts and hotspots associated with plywood manufacturing. Based on our results and a literature review of LCA studies involving plywood, a sustainable and environmentally friendly scenario was proposed for the plywood processing industry to improve environmental performance and sustainability. This study covers the life cycle of plywood production from a cradle-to-gate perspective, including raw material preparation and plywood manufacturing and processing to analysis of environment impacts and hotspots. Analysis of abiotic depletion (ADP), acidification effect (AP), primary energy depletion (PED), freshwater eutrophication (EP), global warming potential (GWP), and particulate matter (RI) were selected as major impact categories in this study. All data were obtained from on-site measurements (plywood production) and investigations of the Eco-invent database and CLCD database (upstream data of materials and energy). These data can be ignored when environmental contributions comprise less than 0.001% of environmental impact and auxiliary material quality is less than 0.01% of total raw material consumption. An eco-design strategy with eco-alternatives was proposed: pyrolysis bio-oil can be used to produce green resin to replace traditional phenolic formaldehyde (PF) resin to decrease the impacts of GWP, PED, AP, PM, and especially ADP and EP. A new technology of gluing green wood was used to replace conventional plywood production technology; wood waste could undergo a gasification process to produce resultant gas rather than combusting. Plywood was also compared with other wood-based panels in China to identify additional scenarios to improve environmental sustainability.

English

In this study, life cycle assessment (LCIA) was used for the assessment and evaluation of the environmental performance of the Khaya lumber manufactured by three firms in Ghana. The work mainly aims to assess all possible effects to the environment, measure the carbon footprint for Ghana Khaya lumber and offer an Environmental Product Declaration (EPD) for Ghana Khaya lumber. The results show that the average environmental effect of the Khaya lumber per cubic meter in relation to GWP was 253 kg-CO2-Eq; AP, 3.9 kg SO2- Eq; EP, 2.6 kg Phosphate (PO4)-Eq; POCP, 0.56 kg Ethylene-Eq. The GWP, AP, EP and POCP match very well the results of LCIA for 1 m3 rough-sawn, kiln dried US lumber cradle to gate for 19 diverse species and the LCA results for environmental product declaration of tropical plywood production in Malaysia and Indonesia. The EPD results give useful, confirmed and equivalent information concerning the possible environment effect of Khaya lumber manufactured by three firms in Ghana. A detailed and clear LCA for the timber industry offers industry with precise areas for making physical and economic savings to benefit the wealth of the environment and industry. Key words: Environmental assessment, tropical timber, life cycle assessment.

Assessment and application of phosphorus/calcium-cottonseed protein adhesive for plywood production

Cottonseed protein is a potential alternative to formaldehyde-based adhesives as a renewable resource without negative environmental impact in use. Like other protein-based adhesives, unmodified cottonseed protein isolate needs improved water resistance. Thus, in this work, the effects of phosphoric acid (H3PO4), dipotassium hydrogen phosphate (K2HPO4), calcium oxide (CaO), and calcium hydrogen phosphate (CaHPO4) at four concentrations (i.e., 20, 40, 60, and 80 mM) on the adhesive strengths of cottonseed protein isolate were evaluated. Compared with control (protein without modifiers), H3PO4 (20 and 40 mM) increased dry, wet, and soaked strength by 20–30, 72–88, and 24–30%, K2HPO4 (40 and 60 mM) by 8–22, 2–10, and 1–8%, CaO (20 and 40 mM) by 8–16, 11, and 6%, and CaHPO4 (40, 60, and 80 mM) by 12–26, 6–13, and 7–14%, respectively. Cottonseed protein with 40 mM H3PO4 had the best adhesive performance, especially water resistance (88% higher in the wet strength than control), due to the increased crosslinking at its isoelectric point caused by acidity of H3PO4 (pH, 4.13). Solid state 13C nuclear magnetic resonance spectroscopic analysis showed that the amino groups interacted with these P compounds in the blending adhesives. Finally, an optimized protein adhesive preparation was applied to bond 3-ply pine plywood. The water resistance of these 3-ply strips passed the industrial soak test as Type II plywood used for hardwood and decorative plywood, indicating that the adhesive under optimal conditions can be used as a green and environment-friendly adhesive resource in wood industry.

Effects of the export restrictions on birch log market in Northwest Russia

Russia is planning to impose an export quota for birch logs in 2018, reasoned by the increasing export volumes and rising price of birch logs harming the domestic plywood production. In this paper, the possible effects of the planned export quota are analysed by scrutinising the interdependencies between the exports, domestic consumption, and prices of birch logs in Northwest Russia, the largest producer of plywood and exporter of birch in Russia. According to the results, the domestic demand has determined the price development of birch logs, while the effect of exports has remained week. It can be concluded, that the total demand for birch logs in Northwest Russia has been dominated by domestic consumption and it seems that despite the parallel rising trends of domestic use and export volumes, the birch log resources and harvesting volumes have been adequate to meet the increasing demand. Notwithstanding the periodical fluctuations, the long term development of price of birch logs has remained rather steady in the region. Thus, the effect of the quota on birch log price development in the domestic Russian roundwood markets would probably remain small. However, the quota would likely be contrary to trade agreements, add to bureaucracy and destabilise the operating environment of logging companies as well as international buyers of Russian roundwood.

Mechanical and rheological properties of wood plastic composites based on polypropylene and birch plywood sanding dust

Article summarizes investigation results of thermal, mechanical and rheological properties of industrially prepared two new wood plastic composites, based on a virgin polypropylene (PP) and birch plywood production residues-plywood sanding dust (PSD). The studies revealed that the tensile strength of composites increased about 25-30% and the modulus for 4.0-4.5 times, but the lightness, the whiteness degree and the common colour changes are smaller in comparison with previously investigated similar composites [5,6].The softening temperatures by VIKA of approbated composites are 154.4 and 158.6°C. The starting temperatures of thermal oxidation are 250.5 and 253.5°C and the thermal expansion of samples at 90°C is only 3%. The rheological experiments showed the decrease of composite melts viscosity with the increase of temperature and the shear rate, but the fluidity index is smaller than 1, that is typical phenomenon for pseudoplastic polymer liquids. The SEM pictures of the fractured surface replicas confirmed that the composites failure has mixed character: partially fracture the polymer matrix and the border surface of polymer matrix and wood fibre.

Investigation of epoxy‐based wood adhesives

ABSTRACTCold‐set epoxy‐based wood adhesives were investigated for production of exterior plywood. Effective adhesives were composed of bisphenol A diglycidyl ether (BPADGE), polyamidoamine (PAA), and polyethylenimine (PEI). Three‐ply plywood panels were prepared with BPADGE–PAA–PEI adhesives and evaluated for their strengths and water resistance in accordance with a standard for exterior plywood. The effect of BPADGE/(PAA + PEI) weight ratio, PAA/PEI weight ratio, the mixing time for preparing the adhesive, and the pressing time for making plywood panels on the water resistance and the shear strengths of the plywood panels was investigated. The pot life of the adhesive was also measured. Plywood panels made with the BPADGE–PAA–PEI adhesives met the industrial requirements for exterior applications. Adhesion mechanisms are discussed in detail. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47741.

Influence of cold tack properties on bond performance of cured urea\u2013formaldehyde resin

Urea–formaldehyde resins are capable of forming cold tack, which is needed in plywood production. Cold tack is influenced by various factors such as veneer moisture content, veneer temperature, and pre-press time. Tensile shear strength and wood failure percentage of bonded birch veneers were examined. Based on statistical analyses, it was concluded that the factors influencing cold tack do not significantly influence the performance of the cured bond line.

On the expediency of environmentally-friendly use of wood waste in the Baikal region

An important direction in ensuring technosphere safety is the reduction of the amount of waste produced by the timber industry and emissions of harmful substances into the environment. Environmentally friendly recycling of woody biomass is expedient in terms of environmental protection and contribute to energy consumption. The purpose of this work is to estimate woody biomass resources in Russia and in the Baikal region (Irkutsk region, Buryatia and Zabaykalsky Krai) in terms of the energy use. The data of public statistics on the volume of harvested wood and products of the timber industry of the Russian regions were used. Based on the analysis of waste generation standards, the resources of wood waste generated during wood harvesting, production of sawn timber, plywood and cellulose were evaluated. The calculations showed that 94±18 million m3 of wood waste is generated annually in Russia. Significant waste wood biomass (about 19 million m3 / year, or 5.6 million tons of coal equivalent) is located in the Baikal region. Most of this biomass is concentrated in Irkutsk region (about 90% of woody waste from the Baikal region). This wood waste has to be recycled to prevent environmental and economic damage. Disposal of waste will help avoid littering of territories, forest fires, pollution of surface and groundwater which will have a positive impact on the ecological situation in areas of forest harvesting and processing.

Compliance of smallholder timber value chains in East Java with Indonesia's timber legality verification system

The Indonesian Timber Legality Verification System (SVLK) has been developed primarily to address illegal logging in Indonesia, and is licensed under the European Union's Forest Law Enforcement, Governance and Trade (FLEGT) Action Plan. While SVLK was catalysed by concerns about the legality of wood originating from natural forests, it applies to all wood production in Indonesia, including smallholders harvesting planted trees. This study investigates SVLK implementation in value chains originating from smallholder forests planted on private land in East Java Province, where these forests are important assets for both farmers and the forest industries. It follows value chains for two manufactured wood products, blockboard and plywood. There are specific SVLK requirements for each value chain actor, other than the market brokers in these chains. Results reveal the limitations of SVLK architecture in relation to smallholder value chains, variation in compliance practices, and points of ‘illegalisation’ and legalization within the value chains. The blockboard and plywood products from each case study chain claimed SVLK compliance. However, only one of the two case study chains for each product was compliant up to the blockboard or plywood manufacturing stage; and no distinction was made at this stage between SVLK-compliant and non-compliant wood. Consequently, none of the final products from any case study chain are SVLK-compliant. These results illustrate the challenges of designing and implementing timber legality systems for smallholder value chains, and suggest areas of focus to improve SVLK for smallholder value chains.

Investigation of suberinic acids-bonded particleboard

Birch outer bark and residual veneer shorts are one of the main leftovers from plywood production and have a high potential to be converted into value-added products. Birch (Betula pendula) outer bark contains up to 45% (dry basis) of suberin and has been recognized as a promising resource of suberinic acids (SA), where the bonding potential has been proven. Therefore, this study assesses the application of SA as formaldehyde free bio-based adhesive for the production of particleboards (PBs) made of birch wood particles obtained from residual veneer shorts. The solids of ethanol extracted outer bark were hydrolytically depolymerized and SA obtained. A two stage design of experiments, in terms of screening and optimization, was used varying three PB preparation parameters: amount of the binder (c 20–30%), hot-pressing temperature (T 220–230 °C), and duration (t 2–6 min). The binder was evaluated by thermogravimetric, differential scanning calorimetric, Fourier transform infrared spectrometric and scanning electron microscopic analyses. SA-bonded PBs were evaluated in terms of modulus of elasticity and modulus of rupture in the bending test, internal bond strength, and thickness swelling. The properties of the optimized SA-bonded PB (c = 21%, T = 226 °C, t = 5 min) are in the range of PBs standard EN 312 type P3 (requirements of non load-bearing boards for use in humid environment). The achieved superior internal bond strength (2.7 ± 0.5 N mm−2) and instrumental analyses confirmed a high potential of natural SA-based binder to be used in PB production.

Influence of biochar on the soil structure and the content of potassium forms

The results of the laboratory experiment on the effect of biochar on the content of various forms of potassium and the structure of gray forest medium-loamy soil during incubation for 42 days at optimum humidity are presented. The object of the study was a birch biochar obtained with the use of a fast pyrolysis plant from crushed waste plywood production. It was shown that the introduction of birch biochar into the soil resulted in the increase in the content of aggregates of the optimal size according to dry sieving measures. The best results were obtained with the biochar dose of 10%. Introduction of birch biochar into the soil resulted in the enrichment of its water-soluble, exchangeable and reserve potassium forms. The total content of potassium did not change.

Влияние строения и структуры древесины различных пород на расход клея при производстве фанеры

Влияние строения и структуры древесины различных пород на расход клея при производстве фанеры

Анализ применения доломитовой муки в производстве фанеры повышенной водостойкости

Анализ применения доломитовой муки в производстве фанеры повышенной водостойкости

Physical-mechanical Properties of Plywood Produced With Acrocarpus fraxinifolius and Pinus oocarpa

ABSTRACT The present study has the objective of evaluating the physical-mechanical properties of plywood produced with Acrocarpus fraxinifolius wood, as well as the effect of combining their veneer with Pinus veneer. The wood of Acrocarpus fraxinifolius and Pinus oocarpa were used in the production of the panels. The plywood was produced with five veneers; the adhesive used was phenol-formaldehyde, weighing 320 g.m-2. The evaluated properties were: equilibrium moisture (EM), specific mass (SM), water absorption (WA), thickness swelling (TS), shear strength (SS), modulus of rupture (MOR) and modulus of elasticity (MOE) both parallel and perpendicular to the fibers. No statistical difference was observed in the EM and TS, whereas all other properties showed statistical differentiation between the treatments. In general, the use of Acrocarpus fraxinifolius veneers improved the physical-mechanical properties of the compensated ones. Thus, the use of this species in the production of plywood is technically feasible.

ЛЕСНОЙ КОМПЛЕКС: ПРОГНОЗЫ И СТРАТЕГИИ

The authors analyze the information base of the elaborated forecasts and strategies for the timber complex development from the viewpoint of the territorial differentiation in resources and infrastructure availability. The structure of the harvested timber is aligned with the volume and quality characteristics of the wood assortments needed for production of the forecasted types of the final forest product. It is confirmed that the volume of the small-scale wood substance and waste products formed under clean cutting and also under production of board lumber and plywood, cannot be completely utilized within the production of slab materials and pellets. And in the eastern regions when the benefits for transportation to the European countries are cancelled it is unprofitable to process them. The article also gives estimation of the inner market forecast for the main types of forest products which has been attained with the calculations on the base of the inter-regional model , in comparison with the hypothesis built-in the Strategies of the timber complex development. The analysis is given for the main reasons of not fulfilling the tasks which have been put forward under developing the Strategies connected with the changes of the institutional and economic conditions of the timber complex functioning. Also, inflated expectations for the wooden house constructions are noted in the article.

Analysis of wood products from an added value perspective: The Uruguayan forestry case

Uruguay has a forest resource of 1 million ha plantation of fast-growing eucalyptus and pine. Short-fiber pulp is the country second export product in value, but there is also a significant production of plywood and graded kiln-dried timber from both species, used mainly for appearance applications. However, the value chain of the wood industry is not yet fully developed, particularly for pine. This study classified different existing and potential wood products using added value as criteria, calculated at the industry level by adopting a system of inputs and outputs. Hypothetical plants to manufacture these products were technical and economically analyzed: thermally modified timber, cross laminated timber, laminated veneer lumber, pine timber, bleached Eucalyptus kraft pulp, pine bleached chemical thermo-mechanical, medium density fiberboards, oriented strand board and a power plant fueled with forest biomass. The data used for this study was obtained from the final project of undergraduate engineer students of the Faculty of Engineering, Universidad de la Republica, Uruguay, except for the eucalyptus pulp mill, which was proposed by the authors. The results showed that wood products obtained from logs that are the main objective of the plantation presented a higher added value than those manufactured from forest residues, thinnings or chips from the sawmilling industry. Solid wood products for appearance or structural applications are at the top of added value list, considering value added per product, unit of biomass or unit of forest land per year. The integration of the value chain of the products analyzed, linking solid wood products with panels or pulp, has the potential to boost the addition of value of the forest biomass in Uruguay.

Processing Variable Optimization of Plywood Hot Pressed with Ba2+-Modified Phenol-Formaldehyde Resin by a Response Surface Method

Abstract Ba(OH)2 was added in the synthesis of phenol-formaldehyde resin to realize a low-temperature and fast-bonding process for plywood production. Plywood bonding was investigated by studying a number of parameters, such as the glue spread, the amount of curing agent, and the temperature and duration of the hot-pressing process. The plywood bonding strength was characterized by the shear strength of the adhesive layer, and a mathematical model describing the process and the response was developed using a central composite design and response surface methods. The variance analysis revealed that the newly developed model was reliable, with a high signal-to-noise ratio. All the factors and their interactions were analyzed to optimize the bonding process. Thus, seven optimized processes were obtained from the model, and the optimal process conditions were revealed (glue spread: 277.8 g/m2; amount of curing agent: 3.5%; hot-pressing temperature: 108°C; and hot-pressing duration: 34.99 s/mm). The results from repeated average shear strength experiments of five veneer testing samples (1.64 MPa) verified the reliability of the optimized technics.

CARACTERIZAÇÃO DO REFLORESTAMENTO DE PARICÁ NA MICRORREGIÃO DE PARAGOMINAS-PA

O estado do Pará possui uma área extensa de florestas, ricas em espécies que apresentam valor comercial madeireiro e impulsionam de forma direta a economia da Amazônia. Na Microrregião de Paragominas-PA, a produção de compensados constitui uma importante alternativa econômica para o comércio local. Este trabalho teve como objetivo caracterizar a produção da madeira de Paricá proveniente de reflorestamento, como matéria-prima utilizada na produção de compensado, por empresas beneficiadoras sediadas na Microrregião de Paragominas-PA. Foi conduzido um estudo de caso de caráter exploratório e descritivo, para quantificação da produção, identificação da matéria prima utilizada, e análises da estrutura de mercado, do parque tecnológico e da mão de obra empregada. Os dados foram coletados por meio de entrevistas, observação pessoal, conversas informais, participação em reuniões e análise de documentos. Nos resultados, observou-se que as propriedades pesquisadas eram classificadas como de médio e grande porte. Numa mesma área, as espécies de paricá dividiam espaço com eucalipto e soja. As disposições mais utilizadas nas plantações foram: quadrada (3,5m x 3,5m e 3,2m x 3,2m) e retangular (3,0m x 3,5m), contendo respectivamente 816, 976 e 952 árvores por hectare. Contudo, fatores como economia, políticas públicas, insuficiência de embasamentos científicos e tecnologia influenciam na consolidação e no potencial de abastecimento do mercado de compensado regional.PALAVRAS-CHAVE: Florestas Plantadas, Madeira Nativa, Schizolobium parahyba var. amazonicum (Huber x Ducke) Barneby.