共查询到18条相似文献，搜索用时 156 毫秒
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异氰酸酯胶在刨花板中的应用 总被引：3，自引：1，他引：3
异氰酸酯胶作为刨花板胶粘剂，具有刨花含水率适应范围广（０～２５％），施胶量低、无游离甲醛释放、适合制造轻质刨花板等优点。施胶量为５％、密度为０．４５ｇ／ｃｍ３和０．６１ｇ／ｃｍ￣３的二苯基甲烷二异氰酸酯（ＭＤＩ）小黑杨刨花板的物理力学性能分别达到Ａ类刨花板二等品和优等品的指标要求。密度为０．６５ｇ／ｃｍ￣３时，只要ＭＤＩ施胶量达到３％，刨花板的物理力学性能指标能达到Ａ类刨花板的国家标准要求。试验还表明：ＭＤＩ具有较好的耐水性，但耐湿热性和长期耐水性不如酚醛胶。生产１ｍ￣３刨花板ＭＤＩ与ＰＦ和ＵＦ胶粘剂成本比为２．０５：１．７８：１．００。 相似文献
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游离甲醛和人造板释放甲醛（续） 总被引：3，自引：0，他引：3
游离甲醛和人造板释放甲醛（续）马心颜镇ＦｒｅｅＦｏｒｍａｌｄｅｈｙｄｅａｎｄＦｏｒｍａｌｄｅｈｙｄｅＥｍｉｓｉｏｎｆｒｏｍＷｏｏｄＢａｓｅｄＰａｎｅｌｓ（ｃｏｎｔ＇ｄ）ＭａＸｉｎ（ＳｈａｎｇｈａｉＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＷｏｏｄＩｎｄｕ... 相似文献
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真空氨气处理法降低MDF甲醛释放量的研究 总被引：3，自引：0，他引：3
通过对真空氨气处理法降低MDF甲醛释放量的试验研究和实际生产应用 ,结果表明 :采用真空氨气处理法降低MDF甲醛释放量是可行有效的。该法可以把目前市场上各种规格、密度和游离甲醛含量不同的MDF板材 ,处理成游离甲醛含量满足E1级标准要求 (小于 9mg/ 10 0g)的产品 ,同时 ,不影响到板材的性能和质量 相似文献
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通过使用ＬＬＭ型ＵＦ树脂制造橡胶木和赤桉中密度纤维板的研究,评价用该树脂制造橡胶木和赤桉中密度纤维板的适应性。橡胶木和赤桉各５０％比例温和后施以ＬＬＭ型ＵＦ树脂,按照ＭＤＦ常规工艺压制９,１２,１６ｍｍ的试验板。结果表明：板材物理力学性能及甲醛释放量指标均达到ＧＢ１１７１８．２－８９标准规定的要求。 相似文献
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低甲醛释放量脲醛树脂的制备与性能研究 总被引：17，自引：2，他引：15
讨论了可用于制备低甲醛释放刨花板与胶合板的脲醛（UF）树脂制备参数，该UF树脂制备经过4个pH值（1.5,9.0,4.5,8.0)阶段，最后阶段加入尿素的量对UF树脂游离甲醛的含量有着重要的影响。在弱酸阶段随着甲醛与尿素摩尔比和pH值的下降，通过亚甲基键连接的尿素和高分子质量树脂含量增加，而通过亚甲基醚键连接的尿素的含量下降；在碱性条件下甲醛与尿素摩尔比相同的树脂，较高的pH值可以降低游离甲醛的含量和释放量，当添加2%-5%的胶粘剂时，可提高低摩尔比的UF树脂对木材的胶合性能当甲醛与尿素摩尔比达到1：1时，刨花板与胶合板的甲醛释放量可达E1级标准要求。 相似文献
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引入高分子量、高支化度以及端基为尿素的高支化聚脲(HBPU)用于低摩尔比脲醛树脂(UF)改性,利用HBPU与游离甲醛的反应以及与UF组分的共缩聚反应实现树脂耐水性能的提升和人造板甲醛释放量的降低,有效平衡胶合性能和甲醛释放量之间的矛盾。在无溶剂、无催化剂条件下,通过尿素(U)与三(2-氨基乙基)胺(TAEA)的脱氨缩合反应,一步合成了具有尿素端基的HBPU,并对HBPU的分子量分布和结构进行了表征。使用HBPU水溶液,采用UF合成反应后期加入和共混2种方法对UF进行改性,通过胶合板性能测试以及甲醛释放量测定,考察了HBPU添加量和添加方式的影响。凝胶渗透色谱和碳-13核磁共振分析表明,通过本研究的合成方法可以获得具有高分子量、高支化度、尿素为端基且水溶性良好的HBPU,并且随着U与TAEA摩尔比的提高,更多尿素封端产物形成。电喷雾电离质谱对改性树脂的分析结果表明,HBPU不仅与UF中的一部分游离甲醛发生羟甲基化反应,同时与UF组分反应生成了部分共缩聚产物。胶合板性能测试结果表明,共混以及反应后期加入HBPU两种方式得到的改性树脂耐水性能均显著提升。同时,使用添加5%HBPU改性树脂制备的胶合板甲醛释放量较未改性树脂制备胶合板降低41%。HBPU改性同步实现胶合性能的提升和甲醛释放量降低的主要原因在于HBPU在提高树脂支化程度的同时,还起到捕捉游离甲醛的作用。解决UF胶合性能和人造板甲醛释放量之间矛盾的关键在于提升树脂的支化程度,同时降低树脂中游离甲醛的含量,而引入高分子量、高支化度、具有类似尿素反应活性的聚合物是同步实现胶合性能提升和甲醛释放量降低的有效途径。 相似文献
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Physical and mechanical properties of medium density fiberboards (MDF) made from various mixtures of wood fibers and stone pine (Pinus pinea L.) cones were evaluated using European standards. MDF panels were manufactured using standardized procedures that simulated industrial production at the laboratory. Six panel types were made from mixtures of wood fiber/cone flour, 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 percents, respectively. Addition of the cone flour into the MDF significantly reduced formaldehyde emission from the panel. In addition, the addition of 10% cone flour also improved water resistance of the MDF panels made using urea–formaldehyde (UF) resin. However, further addition of the cone flour into the panel negatively influenced their water resistance. Flexural properties and internal bond strength decreased with the increase of cone flour content in the panel. The UF resin is the main source of formaldehyde emission from the UF-bonded wood-based panels. Depending on addition of the cone flour in the panels, the formaldehyde emission values ranged from 2.6% to 55.3% lower than the panels made from 100% wood fiber. Based on the findings obtained from this study, pine cone can be used as a renewable biological formaldehyde catcher as an alternative to the traditional formaldehyde catchers for E1 Class MDF manufacture. 相似文献
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用异氰酸酯胶生产中密度纤维板的尝试 总被引：2，自引：0，他引：2
以异氰酸酯为胶黏剂,进行了2种原料的中密度纤维板(MDF)生产试验,分析其生产工艺的特点,并根据我国国标及日本相关标准,对板材的性能与甲醛释放量等指标进行检测。结果表明:用异氰酸酯制造的MDF,其各项指标均优于UF胶的MDF,是一种应用前景广阔的环保板材。 相似文献
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Saim Ates Hasimet R. Kara Cag˘ri Olgun Osman E. Ozkan 《Wood material science & engineering》2017,12(3):158-164
This work investigated some mechanical, physical and free formaldehyde emission properties of heat-treated MDF. For this purpose, MDF panels were subjected to varying heat treatment temperatures (155°C, 165°C and 175°C), durations (2.5?h., 3.5?h. and 4.5?h.) and waiting times after hot pressing (30?min., 120?min. and 600?min). Thickness swelling (TS), water absorption (WA), free formaldehyde emission (FFE), bending strength (BS), modulus of elasticity (MOE), tensile strength perpendicular to fibers (TSPF) for treated and untreated samples were tested and evaluated statistically. Consequently, after the heat treatment values of tensile strength, bending strength and modulus of elasticity were almost negatively affected relatively, but the thickness swelling and water absorption and quantities of free formaldehyde were improved positively of MDF samples. 相似文献
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低甲醛释放蔗渣中密度纤维板用脲醛树脂 总被引：6，自引：0，他引：6
以脲醛树脂结构形成特征为基础,研制了一种甲醛释放量低、内结合强度高的适用于蔗渣中密度纤维板生产的脲醛树脂胶粘剂。使用结果表明,所压制的蔗渣中密度纤维板物理力学性能达到国家标准要求,甲醛释放量可控制在２０ｍｇ／１００ｇ左右。 相似文献
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In this paper, we discuss the effects of a nanometer silicon dioxide (nano-SiO2) coupling agent, dispersal methods and the amount of nano-SiO2/urea formaldehyde resin. The results of our study indicate that when nano-SiO2, using KH-550 silane as a coupling agent, was added to UF resin by discontinuous ultrasonic vibration, its properties improved
effectively. When the content of nano-SiO2 was below 1.5%, the amount of free formaldehyde decreased, and the viscosity and bonding strength of resin increased with
an increase in the added nano-SiO2, which did not prolong the curing time. The performance indices of plywood, particleboard and medium density fiberboard (MDF),
hot-pressed by nano-SiO2 (1%)/UF resin (F/U molar ratio=1.2), exceeded the requirements of the National Standard. Their free
formaldehyde emission reached E1 grade. Finally, we analyzed the mechanism of the strengthening effects of nano-SiO2 on UF resin by means of infrared spectrum analysis and X-ray photoelectronic spectrum (XPS).
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Translated from Scientia Silvae Sinicae, 2005, 41(2) [译自: 林业科学, 2005, 41(2)] 相似文献
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Min-Kug Hong Muhammad Adly Rahandi Lubis Chang Hyun Sohn Jeongkwan Roh 《Wood material science & engineering》2020,15(3):163-171
ABSTRACTHigh global production of medium-density fiberboard (MDF) in recent years could generate an equal quantity of waste MDF at the end of its service life, requiring recycling of waste MDF instead of landfilling or incineration. This study investigated effects of the addition of recycled fiber (RF) obtained from surface laminated MDFs with three different materials to the properties of three-layer recycled MDF (rMDF). Three types of surface laminates such as low-pressure laminate, polyethylene terephthalate, and polyester coating were hammer milled, and then went through a patent-pending fiber recovery system to obtain the resultant RFs that were added to the core layer of rMDF. These RFs at three contents (10, 20, and 30%) were blended with 12% of urea-formaldehyde (UF) resin prior to hot-pressing. Statistical analysis showed that the best internal bonding strength, modulus of rupture, and modulus of elasticity of rMDF panels were obtained for LPL-rMDF with a 20% RF content. Thickness swelling, water absorption, and formaldehyde emission of rMDF were reduced by increasing the RF content. These findings suggest that a minimum RF content of 20% can be replaced with virgin fibers for the rMDF manufacture, indicating the feasibility of recycling waste laminated MDF into three-layer rMDF. 相似文献