三聚氰胺改性脲醛树脂胶粘剂对高密度纤维板性能的影响

探索了不同三聚氰胺用量改性对低物质的量比脲醛树脂胶粘剂的理化性质及其压制的高密度纤维板物理力学性能和防水性能的影响,并通过测定不同三聚氰胺用量改性的脲醛树脂胶粘剂的黏度、固含量、固化时间、游离甲醛含量、高密度纤维板的静曲强度、内结合强度和吸水厚度膨胀率,研究其性能。研究结果表明:当三聚氰胺用量由1%增加到10%时,脲醛树脂的固化时间由129 s延长至195 s,游离甲醛含量则先升高后降低;当三聚氰胺用量在6%以内时,对高密度纤维板的物理力学性能无显著影响,但板材的防水性能与三聚氰胺用量呈线性增强关系。本研究为防水、防潮等高性能高密度纤维板的制造提供支持。     

缩甲醛类胶粘剂中游离甲醛含量的测定

现行GB18583-2001标准中是采用乙酰丙酮分光光度法来检测胶粘剂中的游离甲醛含量,但是,在高温及强酸性环境中,缩甲醛类胶粘剂会与去甲醛剂发生水解反应,分解出10倍于原产品的游离甲醛。因此,采用GB18583-2001标准已经不能准确测定出缩甲醛类胶粘剂中游离甲醛的真实含量。通过对原有标准进行适当改进,提出了适用于缩甲醛类胶粘剂中游离甲醛含量的检测方法,经实验验证后得知,采用改进的检测方法,所得测试结果比较准确。     

脲醛胶中甲醛超标难题已得到解决

脲醛树脂胶粘剂中游离甲醛超标而使以其生产的人造板甲醛释放量严重超标，是装饰材料面临的棘手难题，因为甲醛对人体危害很大，2004年世界卫生组织国际癌症研究中心已将甲醛确定为致癌物质。由四川明仿化工研究所研制的“聚合游离甲醛交联剂”用于生产板材，经四川省技术监督局检验，胶合板材游离甲醛释放量符合欧州E1、E2的标准。通过了四川省科技厅组织的专家鉴定。这一成果从源头上破解了家装行业存在的甲醛超标难题。“聚合游离甲醛交联剂”产品自2003年试生产，并投放到沈阳、重庆、成都等地的厂家，用于生产高、中、低密度纤维板、多层板、胶合板、刨花板、竹压板、装饰板、细木工板、木地板、复合地板等。     

关于国家标准《室内装饰装修材料胶粘剂中有害物质限量》测定游离甲醛的一点补充建议

现行国家标准GB 18583-2001是采用"乙酰丙酮分光光度法"测定胶粘剂中游离甲醛的含量,而缩甲醛胶由于合成原料和工艺不同于其他胶粘剂,因而采用现行国家标准GB 18583-2001"乙酰丙酮分光光度法"测定胶粘剂中游离甲醛的含量,不能满足其测定要求.本文通过查阅文献和实验,提出了补充方法,该方法可以准确测出缩甲醛胶中游离甲醛的真实含量,是现行国家标准GB 18583-2001的有效补充.     

聚乙烯醇缩甲醛贴标胶粘剂的研制

介绍了聚乙烯醇缩甲醛改性胶粘剂的制备方法。该胶粘剂具有粘度高,游离甲醛低,稳定性好的优点。     

一种木材胶粘剂及其生产方法

本发明是利用湿法纤维板生产过程中的废水制木材胶粘剂。该木材胶粘剂的组份为(重量％):60～35的甲醛(浓度37％),30～15的尿素(或苯酚),10～50的湿法纤维板废水提取物。方法是利用湿法纤维板热压废水经超滤处理后的截留部份,将其在     

顶空气相色谱法测定内墙涂料及胶粘剂中游离甲醛的含量

采用顶空气相色谱法对内墙涂料及胶粘剂中游离甲醛的含量进行分析测定，并建立了测定方法。该方法简捷快速，灵敏度高，重现性好，适用于内墙涂料及胶粘剂中游离甲醛的测定。     

低游离甲醛脲醛胶合成研究

脲醛胶粘剂因价格低廉、使用方便、有较高的胶合强度而广泛用于纤维板、胶合板等人造板的制造和木材加工工业。当前国内脲醛胶的主要缺陷是产品的游离甲醛含量较高，一般在3％左右，使胶接产品在生产和使用过程中有较高的有毒气体甲醛逸出，严重地污染环境，损害了生产者和消费者的身心健康。随着人们对环境愈来愈高的要求，     

低游离甲醛含量脲醛树脂胶粘剂的研究

研究了低游离甲醛含量脲醛树脂胶粘剂的合成新工艺,探讨了甲醛／尿素摩尔比、反应温度、pH值、以及加料的顺序等因素对脲醛树脂综合性能的影响,并采用三聚氰胺进行了改性,以提高耐水性及进一步降低产品中游离甲醛量。采用乙酰丙酮分光光度法测定了所制备胶粘剂中的甲醛含量。实验结果表明本工艺合成的脲醛树脂游离甲醛含量低、综合性能好,符合绿色环保的要求。     

水基胶粘剂的应用及安全检测研究

综述了水基胶粘剂的特点及应用,对水基胶粘剂中的苯系物质、游离甲醛、邻苯二甲酸酯和重金属铬的检测方法进行了介绍。     

Composite materials manufactured from wood particles modified through a reactive extrusion process

Wood‐based composites such as particleboard and medium‐density fiberboard are currently made with formaldehyde‐containing adhesives. Since the government is continuously developing and implementing very stringent regulations to eliminate formaldehyde emissions into the environment, alternative approaches must be developed to replace these adhesives. This study examined the concept of using a reactive extrusion process as a means of developing a new, formaldehyde‐free binding system for wood composite products. The surfaces of wood particles were modified by grafting maleated polyolefins through a continuous reactive extrusion process. Chemical changes resulting from this treatment were followed by studying the Fourier transform infrared (FTIR), ¹³C nuclear magnetic resonance (NMR), and X‐ray photoelectron spectroscopy (XPS) spectra. The modified wood particles were compression‐molded into panels, which were tested for mechanical properties. FTIR, ¹³C NMR, and XPS data revealed that the chemical reactions have taken place between the hydroxyl groups of wood particles and maleated polyolefins. The mechanical property test results indicated that the composite panels compared favorably with current standard requirements for conventional particleboard. POLYM. COMPOS., 26:534–541, 2005. © 2005 Society of Plastics Engineers     

Effect of different acids during the synthesis of urea-formaldehyde adhesives and the mechanical properties of medium-density fiberboards bonded with them

The characteristics of urea-formaldehyde (UF) adhesives condensed by catalysis with four different acids, namely formic (HCOOH), hydrochloric (HCl), phosphoric (H₃PO₄), and sulfuric (H₂SO₄) acids, under alkaline–acidic–alkaline conditions at a molar ratio F/U = 1.12 were studied. The thermal curing properties of UF adhesives catalyzed with acid were characterized by differential scanning calorimetry at 10 °C/min heating rate. The resin structure examined by ¹³C-NMR spectroscopy showed that the resin catalyzed with HCl had a lower proportion of methylol groups, resulting in a lower level of formaldehyde emission. It was interesting to note that HCOOH resulted in the best overall mechanical properties of the medium-density fiberboard (MDF) panels. The HCl catalyst resulted in the poorest performance, providing the lowest internal bond strength, modulus of elasticity, and thickness swelling, with the exception of the free formaldehyde content. The resin catalyzed with H₂SO₄ had the highest free formaldehyde and the highest formaldehyde emission. H₂SO₄ and H₃PO₄ resulted in MDF mechanical properties relatively lower than for HCOOH. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47256.     

环保型脲醛树脂胶粘剂的合成

根据尿素与甲醛加成一缩合反应机理，利用强酸催化工艺合成低甲醛含量的脲醛树脂胶粘剂，并对主要反应条件：pH值，尿素的投放次数及反应温度对胶粘剂游离甲醛的影响进行了探讨。制得环保型脲醛树脂胶粘剂。     

木质素改性脲醛树脂胶粘剂合成工艺及性能研究

以木质素作为改性剂,采用正交试验法探讨了n(甲醛)∶n(尿素)、木质素加入量和木质素加入时间对UF(脲醛树脂)胶粘剂的游离甲醛含量和胶接强度的影响,并优选出制备改性UF胶粘剂的最佳工艺条件。结果表明:当n(F)∶n(U)=1.6∶1、w(木质素)=40%(相对于尿素质量而言)和前期加入木质素时,UF胶粘剂的游离甲醛含量(0.052 8%)满足室内装饰装修材料用胶粘剂中有害物质限量要求(GB 18583—2001)、胶接强度为6.65 MPa且耐水性明显提高。     

Decreasing formaldehyde emission from medium density fiberboard panels produced by adding different amine compounds to urea formaldehyde resin

In this study, medium density fiberboard panels were produced by adding different ratios of some amine compounds to urea formaldehyde resin, which had 1:1.17 mol ratios. The formaldehyde contents, physical, and mechanical properties of medium density fiberboard panels were determined according to EN standard methods.In this study, it was determined that the formaldehyde emission emitted from medium density fiberboard panels decreased by adding urea, propylamine, methylamine, ethylamine, and cyclopentylamine solution. It was found that the water absorption and thickness swelling values increased slightly; however, the internal bond strength, modulus of rupture, and modulus of elasticity of medium density fiberboard panels also increased substantially, but these properties of medium density fiberboard panels decreased by adding higher ratios of urea solution. It was found that the formaldehyde emission of medium density fiberboard panels decreased 16.5% by using a 16% rate of urea formaldehyde resin and 0.8% rate of urea and ethylamine solution. These decreases were determined as 57% for cyclopentylamine solution addition, 41% for propylamine solution addition, and 48% for methylamine solution addition.     

低游离甲醛含量脲醛树脂胶粘剂的合成

本文根据尿素与甲醛加成一缩会反应机理，利用强酸催化合成脲醛树脂低难胶（游离甲醛含量小于0．3％），并对各种反应条件对游离甲醛含量的影响进行了探讨。     

Production and characterization of high strength,thin-layered,pulp fiberboard using soy protein adhesives

Making thin-layered fiberboard and recycling the fiberboard materials are two major approaches to save quantities of wood fiber in fiberboard manufacture, which offer both environmental and economic benefits to the society and industry. The objective of this research was to develop high-strength, thin-layered pulp fiberboards (TLPBs) using sodium dodecyl sulfate (SDS)-modified soy protein adhesives for packaging applications. SDS-modified soy protein adhesives demonstrated significantly higher bonding strength than did unmodified soy protein adhesive. Results showed that the TLPB with SDS-modified soy flour adhesive (0.05?g/cm² area density and 0.6?mm of thickness) had stronger tensile strength, similar burst index, and similar or better water soaking properties in comparison to commercial solid fiberboard (1.24?g/cm² area density and 1.7?mm thickness).     

Influence of glutaraldehyde on the performance of a lignosulfonate/chitosan‐based medium density fiberboard adhesive

A lignosulfonate/chitosan‐based medium density fiberboard (MDF) adhesive has been prepared using glutaraldehyde as crosslinking agent. Optimization of glutaraldehyde/chitosan mass ratio was carried out based on characterization details involving MDFs’ mechanical and dimensional performances analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X‐ray diffraction. The addition of glutaraldehyde improved the mechanical properties of the MDF significantly, while it negatively affected the dimensional properties. The MDFs using lignosulfonate/chitosan‐glutaraldehyde adhesives (LS/CS‐Glu) with glutaraldehyde/chitosan mass ratios in the range of 0.25–0.75 fulfilled the Chinese national standard for MDF. Chitosan was crosslinked with self‐polymerized glutaraldehyde through C?N linkages which resulted in the reduction of the amide bonds and hydrogen bonds between chitosan and lignosulfonate. The proposed LS/CS‐Glu adhesives can be a promising candidate for traditional MDF adhesives which contain formaldehyde. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45870.     

Preparation and performance of lignin–phenol–formaldehyde adhesives

Steam explosion lignin phenol formaldehyde (SEL–PF) adhesives were prepared by ternary gradual copolymerization. The parameters for the phenolate of steam explosion lignin (SEL) and preparation of SEL–PF adhesives were optimized. Under the optimum phenolate conditions, the phenolic hydroxyl content of lignin increased by 130%, whilst the methoxyl content was reduced by 68%. The SEL–PF adhesives were used to prepare plywoods by hot-pressing. The pH value, viscosity, solid content, free phenol content and free formaldehyde content of SEL–PF adhesives were investigated. The bonding strengths of the plywoods glued with SEL–PF adhesives were determined. The maximum SEL replacement percentage of phenol reached 70 wt%, and the properties of adhesives and plywoods met the Chinese National Standard (GB/T 14732-2006) for first grade plywood.     

木材加工用耐水性苯酚液化树皮-甲醛胶粘剂的研制

树皮是一种来源丰富可再生的天然高分子材料。本文采用高温苯酚液化的方法,在复合酸存在下将落叶松全树皮液化成为木材胶粘剂的原料。研究了树皮液化产物制备木材胶粘剂的合成工艺,特别是碱用量对苯酚液化落叶松全树皮一甲醛胶粘剂各主要性能的影响。结果表明,增加碱用量会缩短树皮胶的贮存期,但可降低胶中的游离甲醛;通过降低树皮胶合成时的终点黏度,并在合成末期用水稀释,可有效提高树皮胶的适用期,并可确保树皮胶具有很好的胶接强度和耐水性、较快的固化速率以及很低的游离甲醛释放量。