树脂型甲醛捕捉剂对脲醛树脂性能的影响

在实验室制备得到树脂型甲醛捕捉剂,考察了甲醛捕捉剂与不同F/U摩尔比脲醛树脂混合使用后制备得到的刨花板力学性能及甲醛释放量。研究结果表明,甲醛捕捉剂的添加能有效降低刨花板的甲醛释放量,但对混合树脂的最终力学强度性能不利。混合树脂的摩尔比F/U是决定相关刨花板力学性能及甲醛释放量的主要因素。当与摩尔比F/U=1的脲醛树脂混合使用时,添加占总施胶量5%甲醛捕捉剂的刨花板甲醛释放量可达到E1级,同时,内结合强度值满足室内级国家标准要求。与摩尔比F/U=1.2的脲醛树脂混合使用,当甲醛捕捉剂的添加量为20%时,刨花板性能达标。     

微囊型甲醛捕捉剂对薄木饰面人造板甲醛释放量的影响

随着薄木饰面板在家具、装修领域中的使用量越来越大,人造板的游离甲醛释放问题也愈发引起人们关注,现有的甲醛捕捉剂一般只能在短期内发挥效果,而对人造板甲醛的长期释放控制效果并不理想。为解决人造板甲醛释放的长期性问题,以尿素为芯材、乙基纤维素为壁材制备微囊型甲醛捕捉剂,探讨不同乳化剂及芯壁比制备的微囊型甲醛捕捉剂对饰面人造板甲醛控释效果的影响。结果表明,当乳化剂为十二烷基硫酸钠、芯壁比为3∶1,乳化剂用量1%、壁材质量分数3%、搅拌速度1000 r/min时,制备出的微胶囊芯材负载效果最好,负载量达到36.24%、负载效率为8.05%。采用该微胶囊以2%的质量比与脲醛树脂胶黏剂混配进行饰面板贴面热压时,得到的薄木贴面板的甲醛释放量相比未处理饰面板降低了37.9%。经过20 d后,微胶囊对其饰面板甲醛的释放仍表现出一定的控制效果,饰面板的甲醛释放量为0.99 mg/L,仅为未处理饰面板的56.9%。说明用微囊型甲醛捕捉剂对饰面人造板进行处理不仅能够对饰面板中的甲醛进行控释,而且在长期的放置、使用过程中也能够持续发挥作用,从而达到降低室内空气中甲醛浓度的目的。     

缓释型甲醛捕捉剂的制备及其在刨花板甲醛释放控制中的应用北大核心

为降低刨花板游离甲醛释放量,研究以尿素为功能性芯材,壳聚糖为壁材,采用乳化交联法制备具有缓释功能的微囊型甲醛捕捉剂,并将其应用于刨花板制备过程中。结果表明:在芯壁材比例为2∶1,水油比为1.5∶1,乳化剂用量2%的条件下制备的微囊型甲醛捕捉剂形状规则,平均粒径在50μm左右,芯材负载量和负载效率达到45.86%和68.76%。相较于未处理材,添加微囊型甲醛捕捉剂的刨花板在第1天、第14天、第28天的甲醛释放浓度分别降低了38.27%、49.74%和25.74%。以微囊型甲醛捕捉剂填充刨花板内部孔隙结构,在芯材缓释降解游离甲醛的同时,影响游离甲醛的扩散迁移路径,从而达到较好的甲醛控释效果。     

用不脱水低摩尔脲醛树脂制造低游离甲醛刨花板与中密度纤维板

试验结果表明差示扫描量热仪 (DSC)能够测得NLFS - 1型捕捉剂与甲醛反应 ,并且这种捕捉剂能够捕捉脲醛树脂胶中的大部分游离甲醛 ,其捕捉量与树脂的摩尔比或游离甲醛量有关。对于低摩尔比 ,不脱水脲醛树脂刨花板和中密度纤维板 ,仅用 5 %捕捉剂就能获得较高的捕捉能力。这些板的游离甲醛释放量均能达到欧洲E1级或国标GB -T11718- 1999A级标准。刨花板后期热处理 ,对板的内结合强度提高明显 ,但板的甲醛释放量略有增加     

甲醛捕捉剂的制备与应用效果评价

通过随机检测市售胶合板与细木工板,验证甲醛的释放量与时间的关系,结果表明,人造板材会不断向周围释放游离甲醛;利用酰肼类与无机盐类化合物等复配成新型甲醛捕捉剂,并用于降低胶合板、细木工板等人造板中甲醛释放量,对3 mm胶合板的降解效果最为明显,从E2级的5.4 mg/L降至0.28 mg/L,我国的E1级规定是≤0.5 mg/L。     

甲醛捕捉剂在胶合板生产中的应用

普通UF树脂胶中添加甲醛捕捉剂H300或H800后,其固化时间明显延长.采用H300或H800改性的UF醛树脂胶黏剂生产胶合板,在保证胶合强度的前提下,板材的甲醛释放量达到国标E2或E1级要求.     

甲醛捕捉剂在刨花板生产中的应用

对添加甲醛捕捉剂对刨花板各项物理力学性能影响的研究结果表明,甲醛捕捉剂对刨花板释放甲醛的吸收效果比较明显,但随着甲醛捕捉剂量的增加,刨花板的内结合强度和表面结合强度有所下降。     

SL—N型甲醛捕捉剂在刨花板生产中的应用

SL－N甲醛捕捉剂具有多用途，高效能的特点，当U／F摩尔比为1：1．4时，仅需加入1．0％－1．5％的捕捉剂即可使胶粘剂中的游离甲醛减少80％，板材甲醛释放量达到25mg/100g，还能适当改善胶与板材的物理性能。     

脲醛树脂胶中甲醛捕捉剂的研究

用FS-1作脲醛树脂胶的游离甲醛捕捉剂。FS-1在调胶时加入。它有三种功能：甲醛捕捉剂、固化剂和改性剂。FS-1不仅能与甲醛迅速反应,而且能与脲醛树脂分子发生交联。试验结果表明：当FS-1甲醛捕捉剂添加量为9％时,刨花板的甲醛散发量能降低42．3％,且符合GB/T4897－92刨花板标准A类一等品要求;刨花板IB提高达83％,MOR提高达37％。胶粘剂的凝胶时间也有所缩短。     

一种降低刨花板甲醛释放量的实用方法

采用甲醛释放量达到E2级的脲醛树脂胶粘剂，在刨花板生产的特定阶段添加甲醛捕捉剂，保持热压曲线不变，生产各种规格的刨花板。结果表明，生产出的刨花板甲醛释放量分别达到了欧洲El和E0级标准，且板材具有优良的物理力学性能。     

Scavengers for achieving zero formaldehyde emission of wood-based panels

This work examines the performance of three formaldehyde scavengers in wood-based panels. Sodium metabisulfite, ammonium bisulfite and urea were applied in different physical forms during particleboard production, and the resulting physico-mechanical properties (internal bond strength, thickness swelling, density and moisture content) and formaldehyde emission levels were compared. Formaldehyde content was measured using the perforator method, and formaldehyde emission was evaluated both by desiccator and gas analysis methods. The chemical reactions involved in each formaldehyde scavenging process are proposed and discussed. The tested scavengers showed distinct performances under the different emission testing conditions, which were interpreted in terms of the stability of the chemical compounds formed upon formaldehyde capture. Sodium metabisulfite proved to be an excellent scavenger for all formaldehyde methods allowing the production of particleboard panels with zero formaldehyde emission.     

甲醛清除触媒在清除人造板中游离甲醛的试验研究

清除人造板中甲醛的后处理试验结果表明,喷涂甲醛清除触媒后的人造板物理力学性能没有明显变化,甲醛清除触媒对不同种类人造板释放出的甲醛清除效果相同,E3级胶合板喷涂甲醛清除触媒后的甲醛释放量小于（等于）0.12mg/L,清除率大于99．08％。     

广宁县竹香骨下脚料制备竹碎料刨花板及其复合改性研究

采用竹香骨下脚料为原料,以脲醛树脂和三聚氰胺改性脲醛树脂胶粘剂制备竹碎料刨花板,并与木纤维复合改性,检测并分析了内结合强度、静曲强度、弹性模量和吸水性。结果表明,在热压温度为160℃时,竹碎料板和竹木复合碎料板的物理力学性能均满足国标规定在干燥状态下使用的普通用板要求。当木纤维与竹碎料复合后,复合板材的静曲强度和弹性模量有一定程度提高,但内结合强度降低。     

测试方法对胶合板甲醛释放量测定结果的影响

以试件封闭情况、取样位置、含水率为影响因子,对杨木胶合板的甲醛释放量进行了检测,探讨胶合板释放甲醛的规律和主要途径.结果表明,①胶合板释放甲醛主要集中在边部端面,与边部端面面积有关,表面封闭与否对其释放甲醛的影响不大;②取样位置对甲醛释放检测值的影响不显著,板材边缘和中心位置的试件的甲醛释放量较大,其余部位相差不大;③胶合板含水率对甲醛释放量的影响显著,在含水率较低时,随着含水率的增加试件甲醛释放量增大.     

ET03助剂降低E1级中纤板生产成本的试验

利用ET03助剂对UF树脂进行改性处理,并将改性前、后的UF树脂分别用于中密度纤维板生产.试验结果表明:改性后的UF树脂在降低10%施胶量的情况下,板材的物理力学性能指标、甲醛释放量仍可达到GB/T 1718-1999<中密度纤维板>E1级标准;每m3的中纤板可降低成本4%～5%.     

The effect of urea pretreatment on the formaldehyde emission and properties of straw particleboard

For manufacturing low-formaldehyde emission particleboard from wheat straw and urea-formaldehyde (UF) resins using urea treatment for indoor environments, we investigated the influence of urea treatment on the formaldehyde emission, physical and mechanical properties of the manufactured particleboard. Wheat straws were treated at three levels of urea concentration (5%, 10%, 15%) and 95℃as holding temperature. Wheat straw particleboards were manufactured using hotpress at 180℃and 3 MPa with two types of UF adhesive (UF-45,UF-91). Then the formaldehyde emission values, physical properties and mechanical properties were considered. The results show that the formaldehyde emission value was decreased by increasing urea concentration. Furthermore, the results indicate that the specimens under urea treatment have better mechanical and physical properties compared with control specimens. Also specimens under urea treatment at 10% concentration and UF-91 type adhesive have the most optimum physical and mechanical strength.     

Effect of nanoclay on some applied properties of oriented strand board (OSB) made from underutilized low quality paulownia (Paulownia fortunei) wood

In this study, the effect of nanoclay on some applied properties of oriented strand board (OSB) made from underutilized low quality paulownia wood was investigated. Organo-modified montmorillonite (MMT) at four levels (0, 1, 3 and 5?%) was added to urea formaldehyde (UF) resin. Some chemical properties of paulownia wood (holocellulose, cellulose, lignin and ash contents, pH value and hot and cold water solubility), mechanical [modulus of rupture (MOR), modulus of elasticity (MOE), internal bond strength, screw and nail withdrawal strengths], physical (water absorption and thickness swelling) properties and formaldehyde emission of the strand boards were evaluated. Mechanical properties of all panels complied with the general-purpose OSB minimum property requirements of European Norm. With increasing 5?% nanoclay to UF resin, mechanical and physical properties of the resulting panels improved and formaldehyde emission decreased. However, none of the panels satisfied the thickness swelling and water absorption requirement. The results of X-ray diffraction and transmission electron microscope analysis confirmed the good dispersion of nanoclay in the resulting OSBs. Using paulownia as a fast-growing underutilized species not only can sustain the forests but also can supply raw material to countries facing shortage of wood.