共查询到20条相似文献，搜索用时 93 毫秒
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ＤＡＰ树脂浸渍纸装饰板李向久，李小东（黑龙江省林业设计研究院）ＤＡＰ树脂即邻苯二甲酸二丙烯酯树脂的简称，是热固性树脂。ＤＡＰ树脂浸渍纸装饰板是原纸浸渍ＤＡＰ树脂，与基材组坯热压后制成的一种装饰面板。与三聚氰胺树脂或聚酯树脂浸渍纸装饰板相比具有外观好、... 相似文献
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木材工业用胶粘剂的现状及发展趋势(续) 总被引：1，自引：0，他引：1
３．３苯酚－甲醛（ＰＦ）树脂 ＰＦ树脂有着良好的耐候性，但存在着成本较高、热压温度高、时间长和对单板含水率要求高等缺点［１２］。在ＰＦ树脂中引入价廉的尿素是降低ＰＦ树脂价格的主要途径。一般来讲，向ＰＦ树脂中引入１０％左右的尿素不会影响树脂的胶合性能和耐老化性，相反可以降低树脂的游离酚和游离甲醛。另外将ＰＦ树脂与ＵＦ树脂共混可以克服ＰＦ的树脂易透胶的缺点。苯酚－尿素－甲醛（ＰＵＦ）树脂的反应机理和结构的研究近年取得了一些进展，在弱碱性条件下，（ｐＨ９．０）反应所得ＰＵＦ树脂中不存在苯酚－亚甲基．尿… 相似文献
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《林业工程学报》2017,(1)
采用硅烷偶联剂KH550改性的低分子量PF树脂,以真空浸渍和涂胶的方式分别制备层压板,测定其吸水性、吸油性、体积电阻率、相对介电常数和介电损耗因数,对比研究了改性树脂、普通PF树脂和外购绝缘PF树脂对层压板电绝缘性能的影响。通过扫描电子显微镜观察显示,低分子量PF树脂能够很好地填充细胞壁纹孔。与普通PF树脂、外购绝缘PF树脂和未改性低分子量PF树脂相比,当KH550用量为苯酚质量的5%时,改性PF树脂浸渍单板制得的绝缘层压板相对介电常数和介电损耗因数最低,分别为2.43和0.016 8;经水煮后体积电阻率最高,为1.59×10~8Ω·cm;改性低分子量PF树脂涂胶层压板的吸油率达到电工层压木标准要求,电阻率也高于普通PF树脂和外购绝缘PF树脂。 相似文献
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为考察杨木和辐射松树脂浸渍材的机械加工性能,参照LY/T 2054—2012《锯材机械加工性能评价方法》,分别对杨木和辐射松的素材与树脂浸渍材及其经过真空热处理的树脂浸渍材的刨削、铣削、钻削、开榫和车削5种机械加工性能进行测试评价。结果表明:1)本试验范围内,在综合评分满分40分情况下,杨木素材、树脂浸渍材和真空热处理树脂浸渍材的总评分分别为20分、30分和25分;辐射松素材、树脂浸渍材和真空热处理树脂浸渍材的总评分分别为24分、33分和29分;树脂浸渍材机械加工综合性能最佳,热处理树脂浸渍材次之;2)杨木和辐射松的树脂浸渍材及其真空热处理树脂浸渍材的刨削、铣削性能均为优秀,车削性能均为良好;杨木和辐射松的树脂浸渍材及辐射松真空热处理树脂材开榫性能良好;钻削性能仅辐射松树脂浸渍材达到优秀;3)辐射松素材与改性处理材的机械加工性能均优于杨木,综合比较,辐射松树脂浸渍材具有较佳的机械加工性能。 相似文献
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油松树脂道的发育过程和组织化学研究 总被引：10，自引：0，他引：10
利用薄切片和组织化学方法对油松茎皮层树脂道发育过程中上皮细胞内树脂滴和淀粉粒的动态变化进行了观察研究。在树脂道原始细胞阶段，树脂滴稀少，淀粉粒２－５个；树脂道形成期间，树脂滴数量逐渐增加，体积增大，淀粉粒也呈递增趋势，两者都均匀分布于细胞质中；树脂道成熟阶段，上皮细胞内树脂滴明减少，主要分布于靠近腔道一侧的细胞质中，淀粉粒数量变化不大，而体积明显减小，通常分布于远离腔道一侧的细胞质中，在树脂道发育 相似文献
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马尾松材树脂含量与其解剖特征的关系 总被引：2，自引：0，他引：2
通过对马尾松不同高度树脂道比量、大小等解剖特征及对应高度、径向的树脂含量进行测定、分析,并对马尾松树脂含量与马尾松树脂道比量、大小及二者积之间关系进行研究。结果表明:树脂含量随高度的增加先减小后增大,组织比量分别是3%、2.667%和2.701%;树脂道的直径分别为136μm、141μm和144μm。树脂含量在径向由内向外大体上呈逐渐下降的趋势。树脂含量与树脂道比量和直径的乘积相关性最高:y=-7.346x2+64.199x-126.67(R=1);与树脂道组织比量1%相关性较高,y=5.659 ln(x)-1.530(R=0.84)。 相似文献
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《林业工程学报》2016,(3)
将聚酰胺-胺作为改性剂添加至低摩尔比脲醛树脂(UF树脂)中,以提高低摩尔比UF树脂的固化速度,增强树脂的胶合强度。通过在UF树脂合成过程中添加不同比例的聚酰胺-胺,考察聚酰胺-胺对不同摩尔比UF树脂的影响,包括树脂性能和所制备板材的力学强度。结果表明:聚酰胺-胺添加比例为2%~3%时,UF树脂的固体含量增加、固化时间缩短、固化温度降低,并且这种优势在低摩尔比UF树脂中的改善效果更为显著。改性后的UF树脂制备板材的内结合强度增大,即使是摩尔比为1.1的UF树脂,所制板材的内结合强度也远大于国标要求。聚酰胺-胺改性UF树脂在固化特性和所制板材性能上的优异表现可以在保证板材力学性能的前提下明显提高板材生产效率,降低生产能耗,这种改性是非常有前途的。 相似文献
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Influence of the melamine content in melamine-urea-formaldehyde resins on formaldehyde emission and cured resin structure 总被引：6，自引：0，他引：6
The effect of melamine content in melamine-urea-formaldehyde (MUF) resins on the formaldehyde emission and resin structure was investigated using six MUF resins synthesized with different F/(M + U) and M/U molar ratios. The formaldehyde emission from the plywood decreased as the F/(M + U) molar ratio decreased and the M/ U molar ratio increased. In addition, the bond performance was enhanced as the M/U molar ratio increased in the MUF resins with a fixed F/(M + U) molar ratio. Quantitative solution13C-NMR spectra of MUF resins revealed that the MUF resins with a high melamine content consisted of more highly branched crosslinkage structure and free melamine compared to the resins with low melamine contents. Furthermore, solid-state13C CP-MAS NMR spectra of cured MUF resins proved that more methylol groups, dimethylene ether, and branched methylene structures were present in the MUF resins with a higher F/(M + U) molar ratio, leading to increased bond strength and formaldehyde emission. There is no significant difference in the linkage structure of the cured resins with the same F/(M + U) and different M/U molar ratios except the ratios of carbonyl carbon of urea and triazine carbon of melamine. Therefore, the lower formaldehyde emission from cured MUF resins with a higher M/U molar ratio might be ascribed to the stronger linkages between triazine carbons of melamine than those of urea carbons. Consequently, the melamine contributed to strong crosslinking linkages in the cured resin structures, leading to lower formaldehyde emission and better bond performance.Part of this work was presented at the 48th Annual Meeting of the Japan Wood Research Society, Shizuoka, April 1998 相似文献
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采用傅里叶变换红外光谱技术对由废弃刨花板制备的再生刨花中已固化脲醛树脂的分布及其活性进行了研究。结果表明，已固化的脲醛树脂主要分布在细刨花中，中粗刨花中极少存在，已固化的脲醛树脂仍有活性基因存在，并有助于再生刨花的再胶合及降低再生刨花板中的游离甲醛释放量。 相似文献
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The durability of isocyanate resins consisting of emulsion-type polymeric diphenylmethane diisocyanate (EMDI) was investigated under constant steam heating. Two kinds of resin, water only-added resin and polyol/water-added resin, were used in this study. The degradation of the resins under steam heating was observed using Fourier transform infrared spectroscopy (FT-IR), weight changes, and thermogravimetric analysis (TGA). FT-IR analysis showed that the degradation reaction of the resins scarcely proceeded for a few hours and then increased significantly. The weights of the resins decreased linearly during steam heating. The thermal stability of steam-treated resins was made clear by TGA. The bond strength reductions of the specimens bonded with the resins were also observed. The best fitting regression function for the behavior of bond strength reduction was determined statistically. The apparent activation energy of each resin was calculated from the regression function, for the half-life period. Considering the calculated values, the adhesion durability of using polyol-added resin was superior to that of using water only-added resin. It was clarified that the durability of the isocyanate resins under steam heating was markedly inferior to that under dry heating.Part of this paper was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, 2000 相似文献
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用交联聚苯乙烯-异氰尿酸树脂催化乳酸与正丁醇的酯化反应,发现虽然该树脂的酸性与羧酸相近,但能有效地催化酯化反应,并由此提出了氢键促进催化的反应机理. 相似文献
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The durability of isocyanate resins consisting of emulsion-type polymeric diphenylmethane diisocyanate (EMDI) was investigated under constant dry heating. Two kinds of resin, water only-added resin and polyol/wateradded resin, were used in this study. The kinetic studies based on the weight losses of the resins were carried out by isothermal thermogravimetry (TG) at temperatures ranging from 260° to 320°C. The apparent activation energies of the resins were calculated for weight losses of 5%, 10%, and 15%. The values of apparent activation energy of the resins increased with increasing weight loss. The bond-strength reductions of the specimens bonded with the resins were observed at various temperatures from 120° to 180°C. The best-fitting regression function for the behavior of bond-strength reduction was determined statistically. The apparent activation energy of each resin was calculated from the regression function for the half-life period. According to the calculated values, the adhesion durability of polyol/wateradded resin was superior to that of water only-added resin. To speculate on the changes in weight loss and the chemical structure of the resins in the glue lines under dry heating, changes in the cured resins were also observed.Part of this paper was presented at the 49th Annual Meeting of the Japan Wood Research Society, Tokyo, 1999 相似文献
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CHAI Yubo LIU Huanrong LIU Junliang Research Institute of Wood Industry Chinese Academy of Forestry Beijing P.R.China 《中国林业科技(英文版)》2007,6(1):19-24
Adding low molecular weight resins into wood can overcome wood intrinsic defects, which is a new approach for the high efficient utilization of plantation. This paper reviews the researches on low molecular weight resins modifying wood, including different impregnating resins, impregnation technologies, properties of treated wood and mechanism of modifying wood. In the end, some suggestions and prospects are put forward. 相似文献
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粉状酚醛树脂胶粘剂的制备与性能 总被引：2，自引：0，他引：2
探讨了粉状酚醛树脂胶粘剂的制备和性能,研究结果表明,通过适当参数下的喷雾干燥可制得性能较佳的粉状酚醛树脂胶,直接利用粉状酚醛树脂胶所制备的竹大片刨花板性能优于同等条件下液态酚醛树脂胶竹大片刨花板,且达到加拿大标准"CAN3-O437.0-M85 Waferboard and Strandboard"的要求。 相似文献