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低毒脲醛树脂胶粘剂在E1级胶合板中的应用 总被引:1,自引:0,他引:1
在低毒脲醛树脂胶粘剂合成过程中加入淀粉或氧化淀粉,能有效地改善胶合板板坯的预压性能和胶合板的胶接强度.当淀粉、氧化淀粉加入量为合成低毒脲醛树脂胶粘剂所用尿素量的30%~40%时,达到较好的使用效果.通过在低毒脲醛树脂胶粘剂调制过程中加入低成本API对低毒脲醛树脂胶粘剂进行改性,亦能改善胶合板板坯的预压性能和胶合板的胶接强度.试验表明,随着低成本API加入量的增加,胶合板的预压性能、胶接强度都有明显提高.考虑成本原因,低成本API的加入量为3%~10%即可达到较好的使用效果.改性低毒脲醛树脂胶粘剂能适应多层胶合板的生产。 相似文献
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在低毒脲醛树脂胶粘剂合成过程中加入淀粉或氧化淀粉,能有效地改善胶合板板坯的预压性能和胶合板的胶接强度。当淀粉、氧化淀粉加入量为合成低毒脲醛树脂胶粘剂所用尿素量的30%~40%时,达到较好的使用效果。通过在低毒脲醛树脂胶粘剂调制过程中加入低成本API对低毒脲醛树脂胶粘剂进行改性,亦能改善胶合板板坯的预压性能和胶合板的胶接强度。试验表明,随着低成本API加入量的增加,胶合板的预压性能、胶接强度都有明显提高。考虑成本原因,低成本API的加入量为3%~10%即可达到较好的使用效果。改性低毒脲醛树脂胶粘剂能适应多层胶合板的生产。 相似文献
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3.胶头的硬度规格
胶头硬度是在制作胶头时配料中所添加的硅油量的多少有关,一般应用在溶剂型油墨中的胶头配料中添加的硅油量是不多的。胶头中,硅橡胶与硅油的比例,有60%:40%~100%:0%,这些比例的变化就可以制作出肖氏硬度为50°~40°,40°~30°,30°~20°等硬度不同的胶头来。其硬度会影响印刷质量和印刷中胶头的使用寿命,硬胶头的印刷效果好、寿命长(例如承印面曲率大的工件等)。 相似文献
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近年来,为提高平装书刊的装订质量,书刊印刷企业普遍采用和推广了胶订工艺。胶订工艺以其工艺流程短,出书快、书本平整美观、装订质量稳定、生产效率高而受到各书刊印刷厂的青睐。目前,胶订书刊在整个出版发行数量中已占有越来越大的比重。胶订工艺是一种利用胶粘剂作联接材料将书帖联结、使其成为册的一种平装书籍加工装帖方法,所用的胶粘剂即热熔胶是一种100%可熔性聚合物固体,经加热熔融到一定温度(一般在160℃~180℃),达到所需的流动性和粘附力时,通过涂胶轮将胶液按一定的胶层厚度、刷胶长度、正确起始位置涂抹到… 相似文献
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人造板产品游离甲醛问题的思考 总被引:2,自引:0,他引:2
新世纪来临之际,林产品工业正发生着史无前例的变化,人造板工业也在不断飞跃发展和更新。有资料预测,21世纪前10年,我国人造板产量将达3000万m3。世界木材工业用胶粘剂约占总胶粘剂产量的70%。而木材工业用胶中,脲醛树脂胶将占到65%-70%。 相似文献
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人类采用胶粘剂进行胶接已有数千年的历史,而合成胶粘剂的发展仅是本世纪二十年代的事情。从原料来看,以高分子材料为主要原料的胶粘剂约占胶粘剂总数的80%,而氯丁胶粘剂又占橡胶胶粘剂的80%;就品种而论,仅美国胶粘剂品种就有五十种以 相似文献
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BL-甲醛消纳剂具有低成本、降醛效果明显、本身环保无毒、使用方便等优点。试验结果表明:当BL-甲醛消纳剂添加量为1%时,刨花板的甲醛释放量降低达40%~75%,力学性能保持基本不变,且符合GB/T4897—92刨花板国家标准要求;胶粘剂的凝胶时间有所缩短。 相似文献
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利用制浆黑液中的碱木素为主要原料,经过羟甲基化改性,甲醛缩合制备纤维板胶黏剂,探索改性木素胶黏剂粘结效果。用正交试验方案设计对碱木素改性、胶黏剂制备工艺进行优化。研究表明:将碱木素进行羟甲基化改性,其活性明显提高。最佳的优化条件:甲醛用量7mmol·g-llignin,pH值10,反应温度70℃,反应时间120min;改性碱木素最佳的加入量比例为20%。用碱木素制备改性木素胶黏剂可利用造纸黑液木素资源,而且具有广泛的应用前景。 相似文献
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Marco Fleckenstein Vladimirs Biziks Carsten Mai Holger Militz 《Holz als Roh- und Werkstoff》2018,76(3):843-851
Rotary cut beech (Fagus sylvatica L.) veneers were treated with four different lignin phenol formaldehyde (LPF) solutions using dimethyl sulfoxide (DMSO) as a solvent. Four of these veneers were bonded with PF adhesive to produce four-layer laminated veneer lumber (LVL). To synthesize the LPF solutions, a commercial phenol formaldehyde resin (PF resin) was individually mixed with three different technical lignins (Indulin AT, BioChoice lignin, organosolv lignin) and lignin cleavage products (LCP) at a ratio of 3:2 (60%:40%). Differential scanning calorimetry showed an increased curing temperature for the LPF resins in comparison to the PF resin. The mechanical and water-related properties of the LPF-modified LVL were shown to be similar or slightly improved compared to PF-modified LVL. Fungal degradation experiments with white-rot fungus (Trametes versicolor) and brown-rot fungus (Coniophora puteana) exhibited no significant differences in the mass loss of the LPF-modified and PF-modified samples except in one case: LVL made from veneers treated with Indulin AT exposed to the white-rot fungus. The resistance to weathering of LVL samples made from veneers treated with technical lignins was low; however, specimens treated with LCP and the reference PF resin displayed a higher resistance to weathering. It is concluded that technical lignins or LCP can, to a certain extent, be used as a substitute for crude-oil based PF resin. 相似文献
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Masoumeh Ghorbani Arunjunai Raj Mahendran Hendrikus W. G. van Herwijnen Falk Liebner Johannes Konnerth 《Holz als Roh- und Werkstoff》2018,76(2):481-487
Suitability of lignin–phenol–formaldehyde (LPF) resoles was investigated for manufacturing paper-based high-pressure laminates. As lignin source, pine kraft lignin and spruce sodium lignosulfonate were compared, substituting 40 wt% of phenol by lignin in each case. The synthesized resins were characterized for their viscosity development, solid content, pH, free formaldehyde as well as free phenol content and B-time. Paper-based high-pressure laminates were manufactured using the two different resins. The laminates were exposed to different test climates and were compared for boiling water resistance, thickness swelling, bending properties and impact energy. The results indicate that pine kraft lignin performs superior to spruce sodium lignosulfonate for utilization in paper based laminates for outdoor usage due to a lower affinity of the pine kraft LPF laminates to water. 相似文献
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木素与酚醛树脂结构相似,可代替部分苯酚制备酚醛树脂胶黏剂。通过对木素胶黏剂的研究现状的系统归纳,介绍了黑液木素制备酚醛树脂胶黏剂的两种方式:一是木素直接替代苯酚,二是木素经活化后再与酚醛树脂结合。合理地利用造纸废液中的黑液木素不仅可以有效地处理大量的造纸黑液,而且可以降低酚醛树脂胶黏剂的生产成本,产生可持续发展的经济效益。 相似文献
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Wood joints bonded with urea-formaldehyde (UF) are weakened by cyclic swelling and shrinking. To study the failure mechanisms in UF-bonded joints, specimens were bonded with unmodified, modified (amine), or phenol formaldehyde adhesive and subjected to accelerated aging. Modification of the adhesive properties increased the cleavage fracture toughness and shear strength of bonded joints and improved the resistance of joints to cyclic swell-shrink treatment and accelerated moist-heat aging. Joints bonded with some modified urea-formaldehyde adhesives were as resistant to these treatments as joints bonded with phenol formaldehyde. Physical and mechanical origins of the improved adhesive performance were determined by microscopic analysis. Cure-shrinkage stresses precracked unmodified adhesive layers and damaged the wood interphase. The damaged interphase was especially susceptible to the effects of cyclic swelling and shrinking stresses. Certain modifiers reduced or eliminated cure-shrinkage cracking and damage to the wood. Moist-heat aging caused molecular scission in the bulk unmodified adhesive layer as revealed by the onset of shear cracking in the adhesive layer and erosion of exposed surfaces. Certain modifiers reduced or eliminated molecular scission and erosion responsible for adhesive weakening in moist-heat aging. We conclude that incorporating flexible amines in the adhesive structure improves the durability and stability of UF-bonded joints. 相似文献
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Stergios Adamopoulos Alireza Bastani Patricia Gascón-Garrido Holger Militz Carsten Mai 《Holz als Roh- und Werkstoff》2012,70(6):897-901
Untreated (controls) and phenol–formaldehyde (PF)-modified beech wood (10 and 25?% solid content) were glued with phenol resorcinol formaldehyde (PRF) and polyvinyl acetate (PVAc). Shear strength of PRF-bonded specimens was higher than that of PVAc-bonded ones under dry and wet conditions irrespective of the pre-treatment. Under dry conditions, only PVAc-bonded specimens exhibited reduction in shear strength due to PF-modification with 25?% PF concentration as compared to the controls. PF treated wood provided inferior bonding under wet conditions with the exception of 25?% PF concentration specimens glued with PRF adhesive. Modification with PF resulted in a decrease of adhesive penetration into the porous network of interconnected cells, especially at 25?% PF concentration. 相似文献
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This paper reports on plywood glued by adhesives based on lignin-phenol-formaldehyde resins. Resin was obtained by polycondensation of sulphate lignin with phenol and formaldehyde in alkali medium. Sulphate lignin was separated from black liquor obtained by delignification of poplar and willow wood. 相似文献
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尿醛预聚体改性木质素絮凝剂对重革废水的脱色效果 总被引:3,自引:0,他引:3
在碱性条件下 ,利用尿、醛对木质素进行共混改性 ,在尿醛的摩尔比为 1∶1时 ,所合成的尿醛木质素絮凝剂用量为 70 0mg/L时 ,色度、COD去除率分别可达到 90 %与 80 %以上 相似文献