使用杨木,落叶松混合木片制化学机械浆

本文介绍加拿大试验室规模进行的速生杨木和落叶松混合木片制造亚硫酸盐化机浆(CMP)的试验过程及取得的研究成果,供造纸同行参考。一、试验过程木片来自筛选过的Saint Maurice地区33±5年树龄的杨木和ST.Edouard地区20±5年树龄的落叶松,在试验室内,使用型号M/K40g型蒸煮器并在拟定的蒸煮工艺条件下(见下表)进行蒸煮。     

浅谈化学热磨机械浆——CTMP

一、概述。化学热磨机械浆简称CTMP,属高得率浆,高得率浆生产有个逐渐发展的过程,最早为磨石磨木浆(SGW),后来出现木片热磨机械浆(TMP),精磨机械浆RMP及压力磨石磨木浆(PGW)等,以上均为纯机械法制浆,虽对成浆质量有所改进,但不明显。     

落叶松化学机械浆

本研究旨在寻找落叶松的亚硫酸盐蒸煮的最佳条件,以得到高得率(85％),并具有良好物理特性的化学机械浆(简称CMP)。 在本研究确定的条件下,得到了两种纸浆(游离度均为400ml csf):1)总得率分别为84.5％和91.5％;2)裂断长分别为6.67km和5.83km;3)撕裂指数分别为11.1mN·m~2/g和11.9mN·m~2/g;4)耐破指数分别为4.15kPa·m~2/g和3.4kPa·m~2/g;5)松厚度分别为2.14cm~3/g和2.44cm~3/g。     

杨木生产化学热磨机械浆

吉林造纸厂1975年从瑞典引进一套使用白松的热磨机械浆(TMP)生产线,1988年改造成化学热磨机械浆(CTMP)生产线,使用杨木生产CTMP浆,用     

落叶松磺化化学机械浆可漂性的初步研究

本文是关于落叶松磺化化学机械浆(SCMP)可漂性的初步研究,探索了影响未漂落叶松SCMP白度的因素和使用常用漂白剂的可漂性。     

试产漂白化学热磨机械浆

吉林造纸厂日产150吨化学热磨机械浆(CTMP)生产线是在原热磨机械浆(TMP)生产线上改造完成的,白度只能达到52～53％(SBD),配抄新闻纸后,成纸的白度也只能维持在52～53％左右。1989年我厂对H_2O_2漂白CTMP进行了生产试验。1991年试生产的漂白化学热磨机械浆(BCTMP),白度平均66.86％,配抄新闻纸的白度达到57％,取得了满意的效果。     

碱性过氧化物机械浆制浆法

碱性过氧化物机械浆(APMP)作为改进传统的BCTMP(漂白化学热磨机械浆)的一种新技术于1989年6月由Sprout-Bauer公司推出。这是一个很独特的制浆方法。木片在磨浆之前,用传统的过氧化物漂白液进行浸渍而将木片漂白。APMP与BCTMP相比,在化学药品用量相同的条件下,两者的强度性质和白度一样。但APMP磨浆能耗要比BCTMP低30～40％,又因为APMP不需要另建漂白车间,所以基建费用也比BCTMP低。     

化机浆在生活用纸中的应用

化学机械浆BCTMP(Bleached Chemi-Themo-Mechanical Pulp)是高得率浆的统称。通常包括传统的化学机械浆ECTMP和过氧化氢预处理化学机械浆APMP。与漂白化学浆不同,化机浆的生产包括化学预处理、机械磨浆、漂白、闪急干燥等工艺流程,主要是通过机械作用把木片分解成单根纤维。     

浅谈化学热磨机械浆

本文叙述了化学热磨机械浆（CTMP）的发展原因，存在的不足，应用，分类，适应品种，使用配比，方法选择及木材材种，木片质量要求和废水处理方法。     

化学机械浆选择性磨浆前纤维束预处理研究

对出一段高浓磨浆的化学机械浆粗浆进行筛分以得到纤维束,并采用选择性磨浆工艺对纤维束进行磨浆,研究了纤维束的预处理对化学机械浆磨浆性能及成纸性能的影响。结果表明,在选择性磨浆的基础上对纤维束进行化学预处理能够进一步降低磨浆能耗,并且能够使磨浆后纤维的完整性得到较好的保持,成纸松厚度较高。     

Sterols and Triterpenyl alcohols in common pulpwoods and black liquor soaps

The amount and composition of lipophilic extractives, and especially of sterols and triterpenyl alcohols, were analysed for six important pulpwood species, i.e., Scots pine, Loblolly and Longleaf pine, Norway spruce, Siberian larch and Silver birch. Sulphate soaps (tall oil soaps) derived from these species were also analysed. Scots pine and Loblolly pine contained the highest amounts and Siberian larch the lowest amounts of lipophilic extractives. The highest amounts of sterols were found in birch. The sterols in wood occurred mainly as esters. Sitosterol was the main sterol in all species. Isolation and analysis of the steryl esters confirmed the natural occurrence of sitostanol esters in wood. Considering the use of sitosterol or sitostanol as cholesterol-lowering component in food products, a high ratio of sitosterol to campesterol is beneficial. This ratio was high in birch and pines but clearly lower in spruce and larch. The highest ratios of sitosterol to campesterol were found in soaps from pines and birch.     

Fertigung und Eigenschaften von schnell abbindenden,zementgebundenen Spanplatten,hergestellt durch Begasung mit Kohlendioxid

Wood particles of spruce and larch were used to fabricate cement particleboards by carbon dioxide injection. The press platen have borings to introduce pressurized carbon dioxide. A seal strip, which also acted as distance bar, was placed between the two press platen in order to avoid loss of carbon dioxide, and to have an even distribution of this gas in the pressed furnish. Vacuum was first of all created, and subsequently pressurized carbon dioxide of 7 bar was introduced. The influences of the following parameters on the board properties were examined: direction of gas injection, injection time, press time, and wood species. The direction of the gas injection showed no significant influence. An injection of one and a half minutes, and a press time of three minutes were sufficient. Boards made of spruce showed better properties than those made of larch. The bending strength of spruce cement particleboards complied the specifications of ISO 8335, however, the thickness swelling were too high. It can be expected that by using a cement of higher strength class the technological properties will be improved. In the case of cement particleboards made of larch the density of the boards, and the portion of wood particles should be increased to improve the properties. Moreover a cement of higher strength class has to be used. The injection process is environmental friendly, because about 86 percent of the carbon dioxide emitted in cement manufacturing is fixed in the fabricated boards.     

Fertigung and Eigenschaften von schnell abbindenden,zementgebundenen Probekörpern,hergestellt durch Begasung mit Kohlendioxid

A mixture of spruce or larch wood particles, a lime rich cement, and water were pressed into specimens using an enclosed mold. The mold enabled connection to a vacuum pump or introduction of pressurized gas. The filled mold was first of all evacuated, and subsequently pressurized carbon dioxide was introduced. The influences of the following parameters were examined: carbon dioxide pressure, water/cement ratio and addition of calcium hydroxide on the maximum hydration temperature, the total hydration time, the surface soundness, the spring-back, the carbon dioxide content, the calcium hydroxide content, and the weight increase of the specimens. Moreover the influence of the storage time (under moist conditions) on the properties of the specimens were determined. Optimum fabrication conditions are: carbon dioxide pressure 7 bar, water/cement ratio 0.3 and addition of calcium hydroxide 10%. Under such conditions the binder solidifies within one to three minutes, and the specimens can be removed directly from the press. The specimens show already 75% of the ultimate strength properties five hours after pressing. Both spruce and larch wood particles are suitable for fabricating of stable specimens.     

Schnelle und zerstörungsfreie Bestimmung von Holzarten mittels FT-NIR in der Zellstoffherstellung

Subject  The calcium bisulphite pulping is limited to softwoods without aromatic heartwood substances. While fir and spruce are admissible, larch, douglas fir and pines must be excluded. Chips deliveries often include these last species, thus causing serious difficulties in pulping. A fast and non-destructive method for the identification of these species is presented.      

The effects of acetylation on the extractives of Sitka Spruce (Picea sitchensis) and Larch (Larix leptoleptis) wood

The extractives of acetylated spruce and larch wood were investigated and compared with their respective control counterparts using Fourier transform infrared to determine the effects of acetylation on extractives. Significant differences were observed among the spectra of organic solvents extractives in the control and modified wood, but no such differences were found in water-soluble extracts. It is postulated that the relatively bulky extract substances resident in the gross capillary structure were modified during the acetylation of wood and subsequently recovered by organic solvents, but the hot water extractives were possibly sugars from hydrolysis of less ordered polysaccharides. The mechanism of extractives action during acetylation is that of a scavenger mopping up unreacted anhydride and by-product acetic acid.     

Berechnung der instationären Temperaturverteilung im Holz bei Erwärmung durch Wärmeleitung

The solution of the mathematical model as proposed in the first part of this paper is presented. The results of experimental investigations on the distribution of temperature in the wood of eight species during steaming in an autoclave and subsequent cooling are described. The mathematical model, in which the boundary conditions of heat exchange were in agreement with those of the experiments was tested. The examination by means of field theory revealed a good quantitative agreement of the mathematical solution with the real technical process. On the basis of this mathematical model, technologies for steaming oak, red beech, macoré, limba, larch, pine and spruce are developed.     

Verbesserung des Langzeitverhaltens von Außenkonstruktionen aus einheimischen Hölzern durch Renovierungsanstriche

Samples of spruce, pine, larch, Douglas fir and oak exposed to several years' weathering were repainted using in part the same paint system as and in part different systems from the original paint. Before applying the new coating each sample was examined as to its state of conservation and its renewal requirements. Particular attention was given to the photolytic lignin degradation. During the weathering period changes in moisture content and in length and shape of the samples were measured at monthly intervals. Results clearly show that all kinds of wooden surfaces-independent of the extent of decomposition-may be coated with almost any paint system after suitable pre-treatment, but the greater the decomposition of the original coating and of the wood, the higher will be the costs involved and the more frequently renewal coatings will be required.     

Effect of high-temperature drying on properties of Norway spruce and larch

In timber drying, mechanical properties may be changed due to treatment temperature and treatment duration. In general, when increasing the kiln temperature, drying time is decreased and some timber properties are negatively affected. In this study, the effect of different drying temperatures (80, 120 and 170 °C) on equilibrium moisture content and sorption rate, on bending strength and stiffness was investigated for Norway spruce and larch from four proveniences and the results were compared to those obtained for heat-treated wood (Thermowood ^®). The experiments confirm earlier research that both treatment temperature and treatment duration affect the properties. High-temperature drying or treatment can be optimized for several applications, yielding strong but not so durable timber or vice versa.     

Mold resistance of medium density fiberboard panels made from black spruce, hybrid poplar, larch and a mixture of S-P-F chips

Eleven types of medium density fiberboard (MDF) panels were manufactured from fresh-felled trees of black spruce, hybrid poplar, larch and a mixture of spruce, pine and fir (S-P-F) wood chips at a target density of 740 kg/m³ bonded with 10% commercial urea-formaldehyde (UF) resin. Black spruce panels were fabricated from fibers located in three wood age zones (1–20, 21–40 and over 40 annual rings) of bottom logs, as well as top, middle and bottom logs, separately. Hybrid poplar panels were made from three clones with codes 915303, 915311, and 915313. Mold resistance of these panels was tested by exposing panels in an incubation chamber set at favourable temperature and relative humidity (RH) conditions for mold growth for 4 weeks. The results indicate that MDF panels made from black spruce juvenile wood (1–20 annual rings) were more resistant to mold infection comparing to the other types of panels based on Duncan’s multiple-range test at 0.05 of probability. Panels made of fibers taken from black spruce transition zone (21–40 annual rings) and mature wood zone (over 40 annual rings), and top, middle and bottom logs, hybrid poplar clones 915303, 915311, and 915313, larch and S-P-F wood chips were not significantly different, and these panels were severely infected by mold after 4 weeks of incubation. Nine fungal species predominately infected the tested samples. This laboratory experiment indicates that MDF panels made from black spruce transition and mature wood, and top, middle and bottom logs, hybrid poplar, larch and a mixture of S-P-F chips are susceptible to mold growth and protection measures are necessary in order to improve mold susceptibility of those panels when used in humid conditions or for exterior applications.

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Schimmelbeständigkeit von MDF-Platten aus Schwarzfichte, Hybridpappel, Lärche und einem Spangemisch aus Fichten-, Kiefern- und Tannenholz

Zusammenfassung Aus frischem Schwarzfichten-, Hybridpappel- und Lärchenholz sowie einem Spangemisch aus Fichten-, Kiefern- und Tannenholz (S-P-F) wurden elf verschiedene MDF-Plattentypen mit einer Solldichte von 740 kg/m³ und einem Anteil von 10% handelsüblichen UF-Harz hergestellt. Die Fichtenplatten wurden aus Fasern von drei verschiedenen Alterszonen (1–20, 21–40 und ausserhalb des 40 Jahrrings liegend) vom untersten Stammabschnitt, sowie separat vom oberen, mittleren und untersten Stammabschnitt, hergestellt. Die Platten aus der Hybridpappel wurden aus den drei Klonen 915303, 915311 und 915313 hergestellt. Die Schimmelbeständigkeit dieser Platten wurde untersucht. Dabei wurden die Platten in einer Inkubationskammer bei einer für Schimmelwachstum günstigen Temperatur und relativen Luftfeuchte für vier Wochen gelagert. Die Ergebnisse zeigen, dass MDF-Platten aus juvenilem Holz der Schwarzfichte (1–20 Jahrring) verglichen mit den anderen Plattenarten gegen Schimmelbefall beständiger sind (basierend auf dem Duncan-Test 0,05). Platten aus Fasern von der Übergangszone vom juvenilen zum adulten Holz der Schwarzfichte (21–40 Jahrring) und von adultem Holz (ausserhalb 40 Jahrring) sowie vom oberen, mittleren und untersten Stammabschnitt, von Hybridpappelklonen 915303, 915311 und 935313, von der Lärche sowie einem Spangemisch aus Fichten-,Kiefern- und Tannenholz unterschieden sich nicht wesentlich. Diese Platten waren nach einer vierwöchigen Inkubationszeit stark von Schimmel befallen. Die Proben wurden überwiegend von neun Pilzarten befallen. Dieser Laborversuch zeigt, dass MDF-Platten aus Holz aus der Übergangszone und adultem Holz der Schwarzfichte, sowie von oberen, mittleren und untersten Stammabschnitten, Hybridpappel, Lärche und aus einem Spangemisch von Fichten-,Kiefern- und Tannenholz anfällig gegenüber Schimmelbefall sind. Aus diesem Grunde müssen vorbeugende Massnahmen ergriffen werden, um die Schimmelanfälligkeit dieser Platten bei Verwendung unter feuchten Bedingungen oder bei Aussenanwendungen zu reduzieren.

     

小径落叶松材制作空间网架杆件的选择与设计

通过对小径落叶松材的力学性能、与金属套筒连接性能及胶粘剂的选择试验,设计用小径落叶松材制作空间网架,扩大了小径材在建筑领域的使用范围。