Panel Industry Research Articles

Possibility of using waste tire composites reinforced with rice straw as construction materials

Agricultural lignocellulosic fiber (rice straw)-waste tire particle composite boards were manufactured for use as insulation boards in construction, using the same method as that used in the wood-based panel industry. The manufacturing parameters were: a specific gravity of 0.8 and a rice straw content (10/90, 20/80 and 30/70 by wt.% of rice straw/waste tire particle). A commercial polyurethane adhesive for rubber was used as the composite binder. The water proof, water absorption and thickness swelling properties of the composite boards were better than those of wood particleboard. Furthermore, the flexibility and flexural properties of the composite boards were superior to those of other wood-based panel products. The composite boards also demonstrated good acoustical insulation, electrical insulation, anti-caustic and anti-rot properties. These boards can be used to prevent impact damage, are easily modifiable and are inexpensive. They are able to be used as a substitute for insulation boards and other flexural materials in construction.

Combined Waste Air and Wastewater Treatment Plant for the Wood Panel Industry

In the last few years there has been a dramatic worldwide growth in the production of wood panels and especially of MDF (medium density fiberboard). The environmental aspects of this development have just recently reached the focus of industrial interest due to increasing environmental requirements by the authorities. The development of a new process which should completely close all production site water cycles and minimize the exhaust of air pollutants is reported.

Rice straw-wood particle composite for sound absorbing wooden construction materials.

In this study, rice straw-wood particle composite boards were manufactured as insulation boards using the method used in the wood-based panel industry. The raw material, rice straw, was chosen because of its availability. The manufacturing parameters were: a specific gravity of 0.4, 0.6, and 0.8, and a rice straw content (10/90, 20/80, and 30/70 weight of rice straw/wood particle) of 10, 20, and 30 wt.%. A commercial urea-formaldehyde adhesive was used as the composite binder, to achieve 140-290 psi of bending modulus of rupture (MOR) with 0.4 specific gravity, 700-900 psi of bending MOR with 0.6 specific gravity, and 1400-2900 psi of bending MOR with a 0.8 specific gravity. All of the composite boards were superior to insulation board in strength. Width and length of the rice straw particle did not affect the bending MOR. The composite boards made from a random cutting of rice straw and wood particles were the best and recommended for manufacturing processes. Sound absorption coefficients of the 0.4 and 0.6 specific gravity boards were higher than the other wood-based materials. The recommended properties of the rice straw-wood particle composite boards are described, to absorb noises, preserve the temperature of indoor living spaces, and to be able to partially or completely substitute for wood particleboard and insulation board in wooden constructions.

Field emission displays: a critical review

The goal of making attractive flat panel displays (FPDs) based on arrays of cold cathodes has now become a reality. Pixtech and Futaba have begun commercial production of low voltage, monochrome field emission displays (FEDs). Moreover, public response to the high voltage, full color, VGA FED prototypes shown by Candescent and Motorola at various technical meetings and exhibits has been extremely positive and encouraging. Yet, the future of the FED industry is uncertain. The tremendous improvements in visual quality and reduction in manufacturing cost of liquid crystal displays, as well as the formidable progress made in other FPD technologies has raised the standard for FEDs. In this article, we first review the status of FEDs based on the Spindt microtip emitter. We focus on the scalability of the Spindt process to large substrates, phosphor selection, high voltage stability, and display lifetime. Second, we discuss in detail the recent advances made in alternate cold cathode technology, including carbon nanotubes and composite materials, and their potential advantages for FPD. This new technology offers a tremendous opportunity to lower capital investment, to cut manufacturing costs and to challenge the existing flat panel industry.

Characterization of the water-insoluble fraction from fast pyrolysis liquids (pyrolytic lignin): Part II. GPC, carbonyl goups, and 13C-NMR

Fast pyrolysis has become an interesting technology for the conversion of solid biomass into a liquid (bio-oil) that can easily be stored and transported. The structural features of pyrolytic lignin is of paramount interest in order to explain reaction mechanisms during pyrolysis and aging processes. In addition, a well-characterized pyrolytic lignin can be of interest for commercial applications such as adhesives in wood based panel industry. This paper describes methods to elucidate the structural configuration of pyrolytic lignin. Using gel permeation chromatography (GPC) the average molecular weight of pyrolytic lignin was determined to be between 650 and 1300 g mol −1. Ratios of hydroxyphenyl-, guaiacyl-, and syringyl- units (H, G, S-units) were obtained from pyrolysis gas chromatography-mass spectrometry (Pyroprobe-GC/MS) and were compared with milled wood lignin (MWL) data. Carbonyl groups were determined by oximation. Based on analytical data, a C 8-formula was established assuming a principal structure of phenyl ethane units. Combined with GPC results an average DP between 4 and 9 was calculated. Evaluation of 13C-NMR spectra shows some small signals indicating residual lignin moiëties with ether structures. However, most of the ether bonds in the native lignin were split. As a consequence pyrolytic lignin seems to consist of oligomeric alkylated aromatic units linked by newly formed bonds, probably CC bonds.

Use of spruce tannin as a binder in particleboards and medium density fiberboards (MDF)

In the recent past, increasing attention has been paid to the use of natural adhesives as a binder in the wood-based panel industry. Nowadays, two German companies are using Quebracho tannin and Wattle tannin for the production of particleboards and medium density fiberboards (MDF), respectively. To date no serious attention has been given to bond fiberboards using tannin derived from spruce bark. Results of research work on the use of spruce tannin as a binder for medium density fiberboards carried out in the last two years are presented. The results reveal that spruce tannin can be used to partially substitute Quebracho tannin in MDF up to about 60%. Such boards still meet the specification of moisture resistant MDF (according to EN 319 and EN 321). Moreover, spruce tannin can be used to 100% as a binder for the production of MDF for indoor use (type MDF EN 622-5).

Review : Testing for Formaldehyde Emission from Wood-Based Products - A Review

Concern about possible health effects from formalde hyde emitted from wood-based panel products manu factured with urea-formaldehyde and melamine-formal dehyde binding resins has led to the development and increasing use of low emission products. To control the emissions a range of tests has been developed which the wood-based panel industry can use to determine the potential of products to release formaldehyde. This pa per reviews laboratory test methods which are based on the extraction of formaldehyde and also the current requirements in European product standards. It further describes the use of chamber tests to measure formalde hyde emission under normal conditions of temperature and humidity. These tests are included in the labelling schemes of some countries and are the subject of a new European standard test method.

Evaluation of HFC-245fa and Pentanes in Polyisocyanurate and Polyurethane Laminated Panel Rigid Foam Formulations

The laminated panel industry in both the United States and Europe has successfully converted from chlorofluorocarbons (CFC) to alternative blowing agents. The U.S. markets championed HCFC-141b, while the European markets concentrated on pentane. Since the production and use of HCFCs will be phased out worldwide by the year 2020, all alternative non-chlorinated blowing agents with zero ozone depletion potential (ODP) and low global warming potential (GWP) need to be evaluated to determine which blowing agent candidates are best suited for the different rigid foam applications. It is crucial for researchers in this field to develop products which meet these stringent criteria to ensure the continued growth of the polyurethane rigid foam industry. Our current emphasis focuses on HFC-245fa and the normal, iso-, and cycloisomers of pentane. As was experienced with the conversion from CFC-11 to HCFC 141b, there are many potential technical challenges associated with blowing agent conversion. These challenges need to be explored by experimentation to ensure a smooth transition into the next generation of blowing agents. At the 1995 and 1996 SPI conferences, work from handmix and full-scale panel evaluations, respectively, was presented which compared properties of foams processed with HFC-245fa to those processed with HCFC-141b. The next phase of our evaluation is to compare foams processed with HFC-245fa to those processed with normal, iso-, and cyclo-pentanes. This paper details a comparative study of these blowing agents in polyisocyanurate and polyurethane rigid-foam systems which currently use HCFC-141b. Full-scale panels were processed on a pilot-scale laminator and were tested for end-use properties.

Resol Resins Prepared with Tannin Liquified in Phenol

An alternative to phenol, a petroleum-based nonrenewable resource, in phenol-formaldebyde resins must be developed to support the wood-based panel industry. Tannins are the best substitute for phenol in this case. Tannin from black wattle (Acacia mearnsii) can be liquified with phenol in the presence of an acid catalyst. In this study, tannin replaced 33 percent of the phenol in the preparation of resol-type plywood adhesives. Loblolly pine (Pinus taeda) plywood bonded with the liquified tannin resin had strengths and wood failures that were comparable to commercial phenol-formaldehyde adhesives and significantly better than unmodified tannin-formaldehyde adhesives when used to bond Southern Pine under bonding conditions commonly employed with phenol-formaldehyde resins

Capacity and Competition: Empirical Evidence on UK Panel Data

Following D. Kreps and J. Scheinkman (1983), it is common to view the difference between Cournot and Bertrand competition as depending on production capacity. Bertrand undercutting is only feasible if firms have capacity to serve the market gained. If firms are capacity constrained, the Cournot model is more appropriate. This paper tests the capacity and competition idea by looking at the relationship between profits and capacity constraints; if capacity constrained firms become more Cournot-like, it should be positive. Using survey data on capacity constraints merged into a panel industry data set for the United Kingdom, the authors find a robust positive relationship. Copyright 1994 by Blackwell Publishing Ltd.

Polyurethane Rigid Foam Systems for Metal-Faced Sandwich Panels for the 1990s

Sandwich panels with polyurethane rigid foam cores are important building elements for a wide variety of applications. They are used for the cost effective construction of industrial and commercial buildingsand in many stages of the food chain, including cold storage, cold rooms and refrigerated transport containers and trucks. The blowing agent used in the foam systems has traditionally been CFC-ll. This has contributed to the excellent thermal resistance of the panels but its use will be phased out by the year 2000. Foam systems have been developed based on a wide variety of alternatives. These are designed to suit various national and international CFC phase-out schedules. These include systems based on 100% CO2, HCFC-22, HCFC-123 and HCFC-141b. In all cases the formulations have been based around the particular blowingagent to obtain the best combination of processing, physical and thermal resistance properties. Because the HCFCs are now accepted to be transitional substances with a finite production lifetime, the foam systems based on HCFC-123 and -141b are designed to be “drop-In” replacements for those based on CFC-ll. This means that all changes are incorporated into the foam system rather than into the production process and that thermal resistance with those blowing agents equals that for systems based on CFC-11. These panels have an important structural role to play and, in addition to the retention of foam strength, the adhesion between the foam and facing plays an important role in the overall performance of the panel. The parameters affecting adhesion have been investigated with the alternative systems and optimised processing conditions determined. A family of foam systems has been developed to serve the metal-faced sandwich panel industry through the 1990s.

Adhesives for the composite wood panel industry

Adhesives for the composite wood panel industry

A Brief Account of Adhesive Use in the Wood-Based Panel Industry of China

Abstract As China is a developing country, its wood-based panel industry is also developing. The annual output of wood-based panels was 690,000 m3 in in 1981, and the amount of adhesives utilized in their manufacture was about 40,000 T annually of which 7&75% was amino resins, 15-20% was phenol resins, and the rest was protein binders.