对丙烯酸系压敏胶粘剂某些性能的改进

丙烯酸酯类压敏胶粘剂,是目前仅次于橡胶类用得最多的压敏胶粘剂。按其形态分类,有乳液型、溶剂型和无溶剂型三种。它们各自都有不足之处,下面分別谈谈对其改进方法。一、对乳液型压敏胶某些性能的改进乳液型压敏胶是近年来发展较快的品     

合成树脂乳液胶粘剂的发展近况

<正> 前言八十年代初国外胶粘剂工业由于通货膨胀、经济衰退、生产不景气的影响而减少了消费量,1983年以后随着经济复苏,胶粘剂的生产也开始好转,但总的增长速度缓慢;在这期间有些品种由于顺应了时代的需要,仍得到持续稳定的发展,合成树脂乳液(水基)胶粘剂就是一例;目前,乳液胶粘剂在世界各主要胶粘剂生产国家中的用量已成为仅次于脲醛、酚醛等热固性通用胶的大品种。如日本1983年合成树脂乳液的总消费量达到39万吨,其中42%用作胶粘剂,以树脂类型来分,则聚酷酸乙烯类占45%,EVA类乳液占13%,聚丙烯酸酯类为40%,其它     

丙烯酸酯类乳液胶粘剂的研究进展

综述了丙烯酸酯类乳液胶粘剂的合成、改性、应用等方面的研究进展。在合成方面,讨论了主要组分的作用及影响因素,在性能方面阐述了改性的方法,并简述了丙烯酸酯乳液胶粘剂的用途。     

改性丙烯酸酯乳液胶粘剂的研究进展

对丙烯酸酯乳液聚合的组成作了简单评述,指出了丙烯酸酯类胶粘剂在实际应用中存在的主要问题,综述了丙烯酸酯类乳液胶粘剂的改性进展.     

增粘树脂在丙烯酸酯乳液胶粘剂中的共聚改性研究

主要研究了增粘树脂种类以及用量对丙烯酸酯类乳液胶粘剂的共聚改性,同时探讨了引发剂、溶剂对乳液胶粘剂的性能的影响。研究发现:氢化松香的增粘效果较好,其适宜的用量为不超过单体总量的10％。     

聚氨酯水分散体改性丙烯酸胶粘剂的性能

用聚氨酯改性的丙烯酸材料是近年来开发应用的一种新型材料,这种改性材料在涂料、油墨和胶粘剂等领域广泛应用。丙烯酸乳液具有和高弹性聚合物掺和性能好的特点。聚氨酯属高弹性聚合物类,它添加到丙烯酸乳液中去,能改进丙烯酸乳液的粘接、柔韧和延伸性能,且不使丙烯酸胶粘剂本身的特点受到影响。聚氨酯水分散体改性的丙烯酸树脂胶粘剂既能提高其粘接强度,又具有色     

纸塑复合胶粘剂的研究现状和动向

纸塑复合制品是现代包装行业应用较广泛的一种复合材料,而纸塑复合胶粘剂是纸张和塑料薄膜复合工本文综述了溶剂型和水基型两类纸塑复合胶粘剂的研究现状,并提出今后的研究方向是开发环境友好胶粘剂、高固含量乳液和功能性胶粘剂.     

会议消息

接触型乳液胶粘剂——丙烯酸类—醋酸乙烯共聚乳液鉴定会会议由林业部科技司主持,于1982年11月5—6日在南京举行。该胶粘剂是由中国林科院林化所研制成功。与会代表认为这种胶粘剂能在接触压力下快速胶粘,可以用于连续化胶粘工艺;消除了有机溶剂引起的环境污染及火灾危险。该胶粘剂属国内首创,与美国研制的一种新型丙烯酸     

高固含量水性丙烯酸酯乳液制备及其作为胶粘剂应用进展

高固含量水性丙烯酸酯乳液作为胶粘剂可分为压敏胶粘剂、纸塑复合胶粘剂、塑木复合胶粘剂、木材胶粘剂、建筑胶粘剂、纺织胶粘剂、汽车胶粘剂等;介绍了水性丙烯酸酯乳液的制备及应用,展望了其应用前景与发展方向。     

改性PVB木材胶粘剂的研制

采用种子乳液聚合法制备聚丙烯酸酯乳液,再与松香改性PVB乳液混合制成复配木材胶,讨论了改性PVB乳液、保护胶体聚乙烯醇、乳化剂和引发剂的用量,以及丙烯酸酯类单体的配比、搅拌速度和反应温度等因素对胶粘剂性能的影响,得出了生产木材胶粘剂的最佳工艺。该胶粘剂具有水溶性好、初粘力大、粘接强度高、固化时间短等优点,显现出广阔的应用前景。     

大豆基木材胶粘剂的研究进展

综述了大豆基木材胶粘剂的应用原理、历史和研究进展,重点介绍了豆胶的新型交联体系,指出了豆胶存在的问题.     

Lignin-based copolymer adhesives for composite wood panels – A review

Lignin is a natural and renewable organic compound that can be easily obtained from spent pulping liquors. It can be used as feedstock for making wood adhesives. Nonetheless, lignins need to be modified to enhance reactivity prior to being used as feedstock for making wood adhesives. Appropriate crosslinkers are also needed to ensure the bonding quality of the lignin-based wood adhesives. In the present review, the drawbacks of using lignins alone as wood adhesives, modifications to enhance the reactivity of lignins and production of lignin-based copolymer adhesives for composite wood panels are reviewed and discussed. The objective of this review is to provide background information about the recent status on the development of lignin-based copolymer adhesives for the production of composite wood panels as well as the future prospects of these adhesives in industry. Several modifications such as demethylation, oxidation, methylolation, phenolation, reduction and hydrolysis have shown promising results for enhancing the reactivity of lignins. Several crosslinkers such as phenolic resin, tannin, polymethylene polyphenyl isocyanate (pMDI), furfural and ethylenimine are capable of copolymerizing with lignins to produce lignin-based wood adhesives. The performance of composite wood panels bonded with modified lignin-based copolymer adhesives have been shown to meet the requirements of relevant standards. The main obstacles for the composite wood panels industry to widely adopt to lignin-based copolymer adhesives are the economic and technical issues. Nevertheless, lignin modification methods are proving to enhance the reactivity of lignins and the optimization in such modification methods would justify the economic issue. Together with the public awareness on the safety, health and environment concerns, the utilization of lignin-based adhesives in the composite wood panels industry is feasible.     

Evaluation of block shear properties of selected extreme‐pH structural adhesives by short‐term exposure test

Nine structural adhesives with varying pH were selected to examine the effect of adhesive pH on wood–adhesive bond quality. The adhesives evaluated included four highly alkaline phenol–formaldehyde, one intermediate pH phenol–resorcinol–formaldehyde, two acidic melamine–urea–formaldehyde, and two acidic melamine–formaldehyde resins. Block shear specimens were prepared using Douglas‐fir and black spruce wood. The adhesive performance was evaluated by measuring the shear properties (strength and wood failure) of the specimens tested at the dry and vacuum–pressure–redry (VPD) conditions. Adhesive pH, test condition, and wood species showed significant effects on shear properties. The different adhesives performed differently at the dry and VPD conditions. The high‐pH adhesives (phenol–formaldehyde and phenol–resorcinol–formaldehyde) showed similar high wood failures at both test conditions and performed better than the low‐pH adhesives (melamine–formaldehyde and melamine–urea–formaldehyde), especially after the VPD conditioning. The low‐pH adhesives showed high wood failure at the dry condition, but wood failure decreased significantly after VPD conditioning for both species, indicating that the low‐pH adhesives were less durable than the high‐pH adhesives. High‐pH adhesives did not have a negative impact on the strength of the bonded specimens. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

加快绿色化 迎接新世纪

在知识经济走向我们的时代 ,木材胶粘剂加快绿色化 ,成为生态材料 ,进入高技术产业行列。在我国 ,下世纪前十年内 ,低毒脲醛胶将成为主流产品 ;现用树脂胶的改性技术日益成熟 ,如三聚氰胺改性脲醛 (MUF)、苯酚改性脲醛 (PUF)等 ;利用天然资源制造的可降解胶粘剂用量提高 ,如木素胶、单宁胶、豆蛋白胶等 ;新产品用胶不断出现 ,如水性异氰酸酯等。另外 ,集科研、开发、生产于一体的专业胶粘剂产业将较快增长。     

木材胶粘剂的研究现状和发展趋势

本文综述了木材胶粘剂的国内外现状；论述了各种木材胶的结构及作用机理，结合各胶种的优缺点介绍了其应用情况，重点讨论了水性聚氨酯胶粘剂作为木材胶的特点及优势：指出了我国木材加工领域用胶存在的问题和发展趋势。     

淀粉基木板胶粘剂的研究进展

淀粉基胶粘剂是胶粘剂“绿色化学”的一个重要发展方向,阐述淀粉及其衍生物在木板胶粘剂中的制备和应用进展,认为淀粉基胶粘剂的耐水性、防腐性及其稳定性仍是当前亟待解决的问题。     

木材胶粘剂的应用现状及发展趋势

主要介绍了木材胶粘剂的发展历史及目前我国主要木材胶粘剂的品种、应用范围、优缺点,并分析了木材胶粘剂未来的发展趋势。     

工业木质素在木材胶粘剂中应用的研究进展

工业木质素应用于木材胶粘剂的研究历史很长,但目前仍停留在小试或中试阶段,并没有工业化生产。结合木质素的基本结构和化学改性,综述了其应用于酚醛树脂、脲醛树脂、三聚氰氨甲醛树脂和聚氨酯胶粘剂等常用木材胶粘剂及环保木材胶粘剂中的现状。指出了工业木质素应用于木材胶粘剂未来研究的方向。引用文献26篇。     

Shear Refinement of Formaldehyde-Free Corn Starch and Mimosa Tannin (Acacia mearnsii) Wood Adhesives

The aim of this work was to reduce the viscosity of formaldehyde-free corn starch–mimosa tannin wood adhesives, without adversely affecting the mechanical properties of the product. The reduction of viscosity was achieved using shear refinement. The study focused on the physical phenomena before cross-linking of the wood adhesive. The physical (rheological characterization) and mechanical (bond strength) properties of formaldehyde-free corn starch and mimosa tannin wood adhesives were measured. The results showed that the shear refinement (290 rpm and 5 min, optimal conditions) reduced the viscosity of the corn starch–mimosa tannin wood adhesives (from 100 000 to 458 Pa s) with the advantage of being stable over time. Mechanical tests showed that the shear refinement did not influence the mechanical properties of corn starch–mimosa tannin wood adhesives.     

The Role of Adhesives in the Improved Use of our Timber Resources

Adhesives are extremely important to our wood products industry. Most of the wood products we use are reconstituted or bonded in some manner. Continual improvements in adhesives and adhesion science have led to an array of new wood products that have profoundly affected the management of our forest resources. A variety of particleboard products utilizes residues from the forest and primary processing plants, greatly extending our timber supply. Laminated structural members can be manufactured from smaller trees, thus permitting shorter rotations and better forest management. These are but a few examples of the technical advances in wood use made possible by adhesives. Future improvement in wood use will require a continued strong RD&A program in adhesives and bonding systems.