Formaldehyde emission from particleboard

European Journal of Wood and Wood Products - A test method is described and experimental data are presented which compare formaldehyde emissions from edges and surfaces of particleboards. Surface...     

Formaldehyde release from particleboard—Evaluation of a mathematical model

The formaldehyde release from particleboard under changing climatic conditions and with varying amounts of exposed particleboard was studied in a large climate chamber. A mathematical model was developed which describes the influence of the various parameters on the formaldehyde concentration in the atmosphere of a room containing particleboards. After determining the formaldehyde concentration under standard conditions by a laboratory method, the formaldehyde concentration under any other climatic conditions can be calculated. The mathematical relations presented in this paper are of model character, therefore, they cannot be transferred uneritically to every board system.     

Formaldehyde emission from particleboards manufactured with waste materials from plywood industry

Peeling cores, dried veneer residues and plywood edge pieces containing adhesive are used for particleboard production. So, in this study, the effect of waste materials from plywood industry used for particleboard manufacturing on the formaldehyde emission of panels was investigated.     

Inter-laboratory comparison of formaldehyde emission from particleboard using ASTM D 6007-02 method

An inter-laboratory comparison of formaldehyde emission (FE) from laminated (PL) and uncoated (P2) particleboard (PB) with 16?mm thick-E1, used for non-structural and interior applications such as furniture materials and supplied from a commercial plant in the Czech Republic, was performed in two laboratories using the American small test chamber (ASTM D 6007-02). The results showed highly significant differences between the laboratories for PL (P<0.001), and not significant for P2 (P=0.33), and the differences between samples were significant for P2 and PL (P<0.05). The FE values ranged between 0.056 and 0.090 and from 0.088 to 0.099?ppm for PL and from 0.129 to 0.223 and from 0.175 to 0.182?ppm for P2 as measured in laboratories 1 and 2, respectively. There was a good correlation (R ²=0.84) between the formaldehyde values measured for both types of particleboards in the two laboratories. Most of the formaldehyde values were in agreement with the requirements of the California Air Resources Board (CARB) regulation. Furthermore, the results suggested that there was a higher homogeneity between the samples in laboratory 2 than in laboratory 1. The variation was related to the chamber conditions and sampling as well as inter-panel variations.     

伦敦地铁站开建17层混合木结构高楼

伦敦市交通运输管理局计划在地铁萨瑟克站(Southwark Station)建设一栋17层混合木结构商业综合楼,该项目已顺利通过相关部门审批,预计2025年建成。项目设计方是伦敦AHMM建筑设计师事务所,设计图纸显示,这栋混合木结构商业综合楼高度75 m,总建筑面积27871 m~2,其中一楼有230 m~2零售空间。     

Low formaldehyde emission,fast pressing,pine and pecan tannin adhesives for exterior particleboard

Exterior grade particleboard satisfying the requirements of the V100 test, of formaldehyde emission well within the emission standard E1 class, and of pressing times as fast as 8.5 sec/mm can be produced at higher moisture contents using fast-reacting non-modified and non-fortified procyanidin/prodelphinidin tannin extracts such as pine bark tannin extract and pecan nut pith tannin extract. Such results, under the conditions reported are not achieved with the slower reacting tannins traditionally associated with the practice of tannin adhesives. The results reported establish that the faster is the reaction of the tannin with formaldehyde, the lower is the amount of formaldehyde needed to achieve V100 standard, the lower is the formaldehyde emission, the faster is the pressing time achievable and the higher is the tolerance of the adhesive to high moisture content of the resinated wood particles.     

Physico-mechanical properties of particleboard made from heat-treated rubberwood particles

Physico-mechanical properties of particleboard fabricated from heat-treated rubberwood particles were investigated. Reduction in water absorption and mass loss were observed in heat-treated rubberwood particles, and it was associated with the properties of particleboard. The density and moisture content of the particleboard decreased with increasing treatment temperature and time. Heat treatment of particles improved the dimensional stability of the particleboard, but the mechanical properties were adversely affected.     

Empirical correlations between test methods of measuring formaldehyde emission of plywood, particleboard and medium density fiberboard

Since different test methods of measuring the formaldehyde emission (FE) from wood-based composite panels have been used for different countries and regions, this study attempted to establish empirical correlations between three test methods (i.e., 24-hour desiccator, 1 m³ chamber, and perforator) for plywood (PLW), particleboard (PB), and medium density fiberboard (MDF), particularly emphasizing on correlations between the 24-hour desiccator and the 1 m³ chamber method. The desiccator method found statistically high correlations with other two methods, resulting in regression coefficient values ranging from 0.96 to 0.88 for PLW, PB, and MDF samples. In particular, the desiccator method had an empirically high correlation with the 1 m³ chamber method that had been adopted as the reference method of comparing regionally different test methods of measuring the FE of wood-based composite panels by the ISO/TC89.     

Properties of particleboard produced from post-industrial UF- and PF-bonded plywood

An approach based on the recycling of waste plywood as a recovered wood resource for the particleboard industry is described. It is demonstrated that post-industrial urea- (UF) and phenol-formaldehyde (PF) bonded plywood can be effectively shredded to the form of the recovered particles that can be a valuable material in particleboard manufacturing. The effects of shredding conditions and binder type on the recovered particles characteristics and the mechanical properties of the particleboards were analyzed. It is shown that the substitution of 20–100% of virgin particles with the recovered material is possible without affecting the performance of the particleboard.     

The suitability of structural particleboard made from fast-growing tree species

Wood particle gypsum boards were prepared in laboratory under the following conditions: wood particles from chips (Cryptomeria japonica, Paulownia X Taiwaniana, Aleurites montana) 30, 25, and 20%; gypsum 70, 75, and 80% by weight; water-gypsum-ratio 0.35; board density 1.1 g/cm³; pressure 30 kgf/cm²; post curing 8 to 10 days. The MOE (tested by stress-wave-timer) was 2,800.7–4,328.5 N/mm² and the MOR (tested by universal testing machine) was 4.74–10.25 N/mm²; the screw holding strength was ranging from 1.85 to 5.14 N/mm². The wood particle gypsum board made from Taiwan paulownia showed the highest value of mechanical properties. The thickness swelling and water absorption of bonded particleboard were 0.62–22.05% and 18.42 to 35.22% after 2 h soaking in water; 2.73–26.68% and 21.71–44.06% for 24 h soaking, respectively. The effect of gypsum content on mechanical properties of boards was not significant, but the thickness swelling and water absorption of boards were reduced as gypsum content increased.     

Creep research on particleboard

Over the last fifteen years an extensive programme of work on quantifying and predicting creep behaviour of particleboard has been undertaken. This paper first sets out some of the philosophy underlying the selection of test methodology used, and then proceeds to summarise and highlight the principal results obtained under both steady- and unsteady-state environments. Very strong interactions were found in the analysis of variable influencing creep behaviour. The reasons for adopting rheological models as predictive tools are discussed and the merits of a 5-parameter model are illustrated. A 4-parameter model is used to obtain the relative proportions of the three components of creep deflection under different conditions: this procedure clearly demonstrates the significant role of the viscous component in determining creep deflection at high levels of stress and relative humidity.     

Larch tannin adhesive for particleboard

This study was undertaken to evaluate the feasibility of Larch (Larix gmelini) tannin-based adhesive for particleboard. The tannin-phenol-formaldehyde (TPF) (60 percent tannin was used to substitute phenol in the resin) was used to produce exterior grade particleboard according to the L₉ (3⁴) orthogonal design test and the results met the German Standard DIN 68763 V100. It also can be said that the TPF particleboards are comparable to some synthetic phenol-formaldehyde (PF) resin exterior-type particleboards on the basis of contrast test and accelerated aging test. The Larch tannin would be a desirable substitute for phenol as a low cost material and the studied tannin-based adhesive is suitable for industrial application.     

Pine tannin adhesives for particleboard

Pine tannin-based adhesive formulations suitable for the industrial manufacture of exterior grade particleboard are discussed. The formulations described are a combination of substantial amounts of pine tannin extract with melamine-formaldehyde, phenolformaldehyde and diisocyanate wood adhesives. The pine tannin extract/diisocyanate (MDI) formulation appears to be particularly suitable for industrial application. The results obtained at laboratory level with the latter formulation are excellent. The elimination of problems inherent in the chemical nature of pine tannin extracts was obtained by already used industrial and laboratory “separate application” techniques. The formulations and application techniques presented appear to be suitable for most of the more widely distributed pine species such us Pinus patula, P. radiata. P. taeda. P. elliotii and others.     

水泥刨花板铺装成型机

本文介绍了两种常用的水泥刨花板铺装成型机的主要结构及其工作原理,并说明了常用铺装机使用和维护应注意的问题.     

几种竹凉席甲醛释放量检测方法探讨

采用水萃取法、40L干燥器法、（9～11）盱燥器法分别对竹凉席甲醛释放量进行检测,并对测试数据进行分析。研究发现,（9～11）L干燥器法测定甲醛释放量,取样面积相对较大,其试验结果波动较小,相比水萃取法、40L干燥器法,具有更好的稳定性和复珊性。建议LY/T1843-2009《竹席》、GB／T23114-2008《竹编制品》两个标准中甲醛释放量的检测方法统一,采用水萃取法、（9～11）L干燥器法两种方法分别进行测试,两者同时符合要求的产品才能正常使用。