Particleboard effect

Fujimoto, H., Anazawa, T., Ohmiya, Y. and Yamagishi, K. (1991). Dimensional stability of a maleic acid - glycerol (MG) treated particleboard. Effects of MG contents and hot-press temperature. Mokuzai Gakkaishi, 37(5), 456 61. 

Arora, M., Rajawat, M.S. and Gupta, R.C. (1981). Effect of acetylation on properties of particleboards prepared from acetylated and normal particles of wood. Holforschung und Holzyerwertung, 33( 1), 8-10. 

Philippou, J.L., Johns, W.E. and Nguyen, T. (1982). Bonding wood by graft polymerisation. The effect of hydrogen peroxide concentration on the bonding and properties of particleboard. Holzforschung, 36(1), 37-42. 

Subiyanto, B., Yusuf, S., Kawai, S. and Imamura, Y. (1989). Particleboard from acetylated albizzia particles. 1. The effect of acetyl weight gain on mechanical properties and dimensional stability. Mokuzai Gakkaishi, 35(5), 412-418. 

Wolkoff, 1998 Haghighat and de Beilis, 1998). Table 15.7, for example, shows the effects of temperature and relative humidity on the emissions of particular compounds associated with carpet, PVC flooring, sealants, varnish, and wall paint (Wolkoff, 1998). Interestingly, exposure of these samples to N2 rather than air also increased the emissions in some cases. However, using increased temperatures to bake-out buildings and hence lower the concentrations of indoor VOCs does not appear to be particularly effective. For example, Bayer (1991) reports that the total VOC concentrations from particleboard are about the same after as before a 5-day bake-out at 88°C. Similarly, significant levels of HCHO have been observed in a mobile home even after 20 years of use in a hot ambient air environment (Pitts et al., 1989 see later). 

Nelms, L.H., Mason, M.A. andTichenor, B.A. (1986) The effects of ventilation rates and product loading on organic emission rates from particleboard. Proceedings of IAQ 86 Managing Indoor Air for Health and Energy Conservation, ASHRAE, Atlanta, pp. 469-85. 

Effects of Hydrochloric Acid and Succinic Peroxide Activators and Maleic Anhydride on Particleboard Properties Part B Results Using 3 Formulating Agents... 

Adhesive. Urea-formaldehyde water-based dispersions are the most widely used particleboard binders. The low-cost, rapid curing, and colorless properties of urea-formaldehyde adhesives make them the adhesive of choice for most interior particleboard. These adhesives have been continuously improved by the resin manufacturers, resulting in reduced press times without detrimental effects on their storage life or handling characteristics. 

T-mouldings are used to give a machined edge effect not possible with the flat tapes a projection on the back is inserted into a machined groove in the edge of the particleboard. 

There have been many attempts to replace these resins with lignin derivatives for wood composite adhesives suitable for plywood, particleboard and waferboard. Most of these studies have been empirical in nature, and few have achieved further consideration for industrial application. As wood binders, technical lignins are variable in quality and poorly reactive in comparison to conventional resin systems such as phenol-formaldehyde (PF) resins. Consequently, they are not utilized on their own. Indeed, if they were, this would adversely affect production quality and times, and necessitate equipment changes. In the wood composite industry, resins having such deleterious effects are not likely to be used even if savings could be made in terms of material costs. 

The moisture dependence of the two PF-extended lignin adhesives was subsequently determined. Single-layer boards were prepared with the resinated chips at different moisture contents. The adhesive content (10%) and press conditions (170 °C, 15 min.) were kept constant. The results presented in Figure 4 indicate the deleterious effect of high moisture contents of the chips on the strength of the boards. The application of the lignin particleboard adhesive thus clearly requires strict control of the moisture content of the chips. 

A great store of information has been accumulated on the effectiveness of WRPs in protecting exterior wood (J, 117-119, 121, 122, 124-129). The treatments can be applied by vacuum impregnation, by immersion (which is preferred), by brush, or by spray application. They improve the performance of many finishes applied over them and add greatly to the durability of exposed wood. Even chipboard or particleboard, which is very susceptible to moisture, can be protected quite effectively against the effects of outdoor exposure by using a WRP pretreatment followed by a diffusion-resistant coating 126, 130-133). 

All of the above treatments, unless deliberately superficial, are not easy to apply to lumber because of the lengthy time for diffusion and reaction, or because of the difficulties in achieving effective penetration. In recent years, therefore, interest has also centred on improving the dimensional stability and durability of reconstituted panels hardboard, particleboard, medium density fibreboard and new derivatives. 

Particleboard utilizes residue materials from other wood processing operations. Sawdust and shavings predominate, although most plants are able to use chips or flakes made from roundwood to meet specific strength requirements in the product. Cost is the major driver, with the proportion of high cost material such as chips or roundwood limited to that necessary to meet product requirements. Particle size distribution and shape have become more important as the effect of these variables on product quality has been recognised, leading to reductions in cost. 

Thorbjomsson S (1985) Effects on mat density and springbuck in multi-nip precompressors. In Maloney T (ed). Proceedings of the 19th Washington State University Particleboard Symposium, Pullman, Washington, 451-64... 

Reduction in the emission characteristics of unfinished hardwood plywood is currently being achieved primarily by the use of low formaldehyde to urea molar ratio formulations. For the manufacture of hardwood plywood and particleboard, formaldehyde to urea molar ratios have been reduced to a range of 1.15/1 to 1.3/1. An important caveat low F/U ratios perhaps should be considered a proxy for the potential to reduce emissions through improved urea-formaldehyde adhesive technology rather than the exclusive means for improvement. Reducing the F/U ratio is not always the most effective way of reducing emissions in consideration of the variety of hardwood plywood constructions, products, and thicknesses. ... 

Figure 1. Particleboard elution by dry nitrogen sample geometry effects (o shredded 1.0 NCM. A A 25x25x16 mm 0.5 NCM duplicate runs. P = Perforator value in mg/100 g dry board/measured on starting material at " 6 pet moisture content.) (ML85 5428)...

Figure 3. Urea-formaldehyde particleboard elution by nitrogen relative humidity (RH) effects. (0.4 NCM. P as in Figure 1.) (ML85 5430)...

Resin Effects on Gas Elution. Elution experiments were also performed on PF-bonded particleboard and on Southern pine chips (furnish without resin) that had sorbed formaldehyde via room temperature vapor phase equilibration (see Appendix Id and 2). Points to be noted here are as follows ... 

During the past decade, urea formaldehyde and phenol formaldehyde resin binders have contributed greatly to the progress of wood industries. Formaldehyde is widely used as a major component in the production of building materials, such as particleboard and plywood, and in urea formaldehyde foam insulation. However, the emissions of formaldehyde from these products create considerable concerns not only in the working environments but also in residences, mobile homes, and office buildings. These concerns have also been stimulated by reports on the health effects and carcinogenicity associated with formaldehyde exposure. 

The effect on particleboard of an ammonia treatment can also be shown using this testing method. In figure 8 again the ideal mixing model is applied. Notice that the line with the lowest emission is the one on the top. The reason is that the reciprocal values and not the steady state formaldehyde concentrations as such, are plotted. Here the slope is different as well. 

Figure 9 illustrates the effect of veneering on formaldehyde emission of particleboard. For the veneering the same type of resin was used as in the production of the particleboard. Pressing conditions are not comparable. Veneering has increased the equilibrium value a little, from 0.48 to 0.56 mg/m. The mass transfer coefficient however, decreased very much. The mass transfer resistance shows an increase from 2,400 sec/m to 11,000 sec/m. In the case at issue, the formaldehyde concentration, at a loading factor of 1 m /m of the veneered particleboard, is below that of the bare particleboard, only at a ventilation rate in excess of 0.2 per hour. 

The U.S.Department for Housing and Urban Development s rule 3280.308 established formaldehyde emission standards for particleboard and hardwood plywood paneling used in mobile homes. These standards took effect February 11, 1985. The certification program under this rule requires each manufacturer to develop a quality control in-plant testing program that relates to tests conducted in a large scale environmental chamber. 

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