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稻草中密度纤维板用改性脲醛树脂的研究 总被引：2，自引：2，他引：2
对比三聚氰胺、二甲基硅油、硅树脂和偶联剂KH-550四种改性剂改性的脲醛(UF)树脂性能的差别及其对稻草中密度纤维板性能的影响,并进行经济评价,最终确定适用于稻草纤维板的改性UF树脂的工艺条件,同时借助于红外光谱(FT-IR)和差热扫描分析(DSC)研究最佳改性UF树脂的结构和固化特性.结果表明,三聚氰胺改性脲醛(MUF)树脂不论是对树脂性能、板性能改善还是从成本分析方面均为稻草纤维板最佳的胶黏剂,FT-IR显示出与未加三聚氰胺相比,加入三聚氰胺后树脂的羟甲基含量降低了10 %,DSC分析则表明其峰值温度有较大幅度的提高,但放出的热量较少.加入三聚氰胺改性的UF树脂其表面张力变小. 相似文献
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以脲醛(UF)树脂改性杉木为研究对象,采用高温过热蒸汽对其进行热处理,系统研究了热处理温度和时间对UF树脂改性杉木吸湿性和耐湿尺寸稳定性的影响规律。结果表明:与杉木对照材相比,UF树脂改性杉木吸湿性降低,耐湿尺寸稳定性提高;高温热处理能降低UF树脂改性杉木的吸湿性,提高其耐湿尺寸稳定性;与热处理时间相比,高温热处理温度对UF树脂改性杉木的吸湿性和耐湿尺寸稳定性的影响更大,随着热处理温度的升高,UF树脂改性杉木的平衡含水率、弦向湿胀率、径向湿胀率和体积湿胀率均呈先下降后升高的趋势;与杉木对照材相比,热处理UF树脂改性杉木的平衡含水率、弦向、径向湿胀率和体积湿胀率最大分别降低了39.00%、62.02%、69.89%、59.99%;与未经热处理的UF树脂改性杉木相比,热处理UF树脂改性杉木的平衡含水率、弦向、径向湿胀率和体积湿胀率最大分别降低了28.71%、53.42%、65.85%、54.32%。 相似文献
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低毒改性脲醛树脂胶粘剂的研究 总被引：14，自引：0，他引：14
应用胶体理论,在树脂合成过程中期加入改性剂,改性剂添加量为3％,合成了性能良好的低毒改性脲醛树脂 胶。使原料成本降低8％,且树脂胶贮存稳定性好。压制的中密度纤维板,甲醛释放量达到了E1级。 相似文献
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《中南林业科技大学学报(自然科学版)》2017,(12)
本研究以脲醛(UF)树脂改性杉木为研究对象,采用高温过热蒸汽对其进行热处理,系统研究了热处理温度和时间对UF树脂改性杉木力学强度的影响规律。结果表明:与杉木对照材相比,UF树脂改性杉木力学强度显著提高;高温热处理使杉木浸渍材的力学强度降低;随着温度升高和时间延长,杉木浸渍材的抗弯弹性模量和强度、顺纹抗压强度和横纹抗压比例极限应力均呈明显下降趋势;经热处理后,UF改性杉木抗弯弹性模量、抗弯强度、顺纹抗压强度最大分别可降低11.4%、65.1%和17.3%,横纹全部弦向和径向抗压比例极限应力最大分别可降低60.9%和59.6%,横纹局部弦向和径向抗压比例极限应力最大分别可降低36.5%和56.5%。 相似文献
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本公司下属中密度纤维板厂所用的脲酯树脂 ,采用低摩尔比 ( F/ U=1.2 6)树脂 ,树脂酸性反应时间较长 ,缩聚程度大。因而树脂的贮存期一般只有约 60天。具体技术指标如表 1。表 1 脲醛树脂性能指标Tab.1 Characteristic indexes of UF resin检测项目指标值固体含量 / % 5 0± 2粘度 (涂 -4杯 ) / s 16 .5～ 18.5p H值 7.5～ 8.5固化时间 / s 40～ 6 0游离甲醛含量 / % <0 .3密度 / (g· cm- 3) 1.18～ 1.2 0适用期 / (h,2 5℃ ) >4 由于种种原因 ,中密度纤维板车间一度停产 ,库存 35.2 t脲醛树脂无处应用。为避免这批树脂因超期贮存… 相似文献
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以一种新型脲基超支化聚合物为改性剂,对低摩尔比三聚氰胺-尿素-甲醛（MUF）树脂进行改性,并对热压工艺参数进行优化,探讨脲基超支化聚合物改性剂添加量、热压温度、热压因子、板材密度、施胶量等因素对中密度纤维板性能的影响。结果表明：当改性剂添加量为2%,热压温度为185℃,热压因子为20 s/mm,施胶量为14%,板材密度为850 kg/mm3时,纤维板的性能较佳。该工艺条件下中密度纤维板的结合强度及耐水性能改善效果显著,与对照组相比,内结合强度提升109%,表面结合强度提升93%,24 h吸水厚度膨胀率下降30%。 相似文献
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三聚氰胺改性脲醛树脂的制备及其在室外型中纤板上的应用 总被引：1，自引：0，他引：1
介绍了三聚氰胺改性脲醛树脂的主要制备工艺，并对该树脂在室外型中密度纤维板中的使用条件如热压参数、施胶量、板坯含水率等进行了研究。试验结果表明用三聚氰胺改性脲醛树脂压制的中纤板的物理力学性能达到ＧＢ／Ｔ１１７１８－１９９９室外型中纤板的各项指标 相似文献
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Application of cure-accelerated phenol-formaldehyde (PF) adhesives for three-layer medium density fiberboard (MDF) manufacture 总被引：3，自引：0，他引：3
This study was conducted to optimize hot pressing time and adhesive content for the manufacture of three-layer medium density
fiberboard (MDF) through the cure acceleration of phenol-formaldehyde (PF) adhesives by adding three carbonates (propylene
carbonate, sodium carbonate, and potassium carbonate) in the core layer. Carbonate type, carbonate level, PF resin content,
and hot pressing time were evaluated on the basis of the performance of MDF panels prepared. The application of cure-accelerated
PF adhesives by the addition of propylene carbonate reduced both PF resin content and total hot pressing time by 38% and 29%,
respectively, for the manufacture of quality three-layer MDF panels (19.1 mm thickness) under the hot-pressing temperature
of 205 °C. The optimum concentration of propylene carbonate for cure acceleration of PF resin was found to be 3 wt% by weight
based on the resin solids. Bending properties, on one hand, were independent of carbonate type and level, and complied with
the minimum requirements by ANSI. Internal bond (IB) strength, on the other hand, was closely related with carbonate types
and level used.
Received 13 March 1999 相似文献
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低甲醛释放蔗渣中密度纤维板用脲醛树脂 总被引：6，自引：0，他引：6
以脲醛树脂结构形成特征为基础,研制了一种甲醛释放量低、内结合强度高的适用于蔗渣中密度纤维板生产的脲醛树脂胶粘剂。使用结果表明,所压制的蔗渣中密度纤维板物理力学性能达到国家标准要求,甲醛释放量可控制在２０ｍｇ／１００ｇ左右。 相似文献
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The search for new value-added uses for oilseed and animal proteins led us to develop protein-based wood adhesives. Low-fat
soy and peanut flours and blood meal were hydrolyzed in an alkaline state, and PF-cross-linked protein resins were formulated
by reacting the protein hydrolyzates with phenol-formaldehyde (PF) in solid-tosolid ratios ranging from 70% to 50% hydrolyzates
and 30% to 50% PF. Physical properties of medium density fiberboard (MDF) bonded with protein-based phenolic resins were compared
to those of boards bonded with ureaformaldehyde (UF) and PF resins, and flakeboard bonded with soy protein-based phenolic
resin was compared to PF-bonded board. As MDF binders, adhesive properties of protein-based phenolic resins depended upon
protein content of proteinacious materials. MDF board bonded with blood-based phenolic resin was comparable to PF-bonded board
and met the requirements for exterior MDF. Boards bonded with soy-protein-based phenolic resin met requirements for interior
MDF, while peanut-based phenolic failed to meet some of the requirements. Flakeboard bonded with soy-protein-based phenolic
resins was inferior to PF-bonded board but outperformed PF-bonded board in accelerated aging tests. Although they exhibit
a slow curing rate, the cost effectiveness and superior dimensional stability of protein-based phenolic resins may make them
attractive for some uses. 相似文献
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用异氰酸酯胶生产中密度纤维板的尝试 总被引：2，自引：0，他引：2
以异氰酸酯为胶黏剂,进行了2种原料的中密度纤维板(MDF)生产试验,分析其生产工艺的特点,并根据我国国标及日本相关标准,对板材的性能与甲醛释放量等指标进行检测。结果表明:用异氰酸酯制造的MDF,其各项指标均优于UF胶的MDF,是一种应用前景广阔的环保板材。 相似文献
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通过对火炬松制造中纤维板制板工艺条件的研究,探索降低中密度纤维板制造过程中纤维施胶量的可能性。结果表明,火炬松制造中密度纤维板是可行的;采用８％的施胶量制板;板材的主要物理力学性能可达到美国ＭＤＦ国家标准ＡＮＳＴＡ２０８．２－１９９４和我国ＭＤＦ国家标准７０型及８０型特级品的要求。 相似文献
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脲醛树脂胶稻草中密度纤维板的性能 总被引：3，自引：1，他引：3
通过用稻草代替木材制造脲醛树脂胶稻草中密度纤维板的可行性研究 ,探讨了板材密度、施胶量和防水剂等工艺因素对稻草中密度纤维板性能的影响。结果表明 :在实验室条件下 ,当板材名义密度为 0 .8g/ cm3和施胶量为 17%时 ,脲醛树脂胶稻草中纤板性能达到现行国家标准一等品的要求 ;施加 1.2 %的石蜡乳液 ,板材的耐水性亦能满足国标要求 相似文献
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Medium density fibreboard (MDF) was produced from fibres treated with maleated polypropylene wax. The objectives of this study were to investigate the effect of fibre treatment with maleated polypropylene wax on the advancing and receding contact angle and wicking of MDF panels by the Wilhelmy plate method; to verify the chemical reactions occurring between fibres and maleated polypropylene wax by infrared spectroscopy, and to verify if there are relationships with the water absorption of panels. Three maleated polypropylene wax contents (0, 3, 5%) and two resin types (urea–formaldehyde, UF and melamine–urea–formaldehyde, MUF) were considered in this study. Our results showed that the treatment increased the advancing contact angle of panels bonded with UF resin. The receding contact angles of MDF panels produced from treated fibres with 5% maleated polypropylene wax content were also increased by the treatment. Also, the wicking was reduced by the treatment independent of the maleated polypropylene wax content. Reductions of the wicking were 59% for panels bonded with UF resin and 73% for panels bonded with MUF. Relationships between the wicking and water absorption were observed. Chemical analysis realized by infrared spectroscopy did not detect the presence of an esterification reaction between wood fibres and anhydride groups of the maleated polypropylene wax. This suggests, therefore, that an esterification reaction did not take place or that chemical modifications were so small that they are not visible by infrared spectroscopy. 相似文献