家具实木胶接件剪切强度的测定与分析

在旧标准的基础上,完善了用力学试验机来测定实木胶接件剪切强度的试验方法。此次试验通过对钢制夹具进行的合理改良,提高了相关设备的精度,并分别选取楸木和柞木的胶接试件,在顺纹测试的基础上增加了横纹状态下剪切强度的测定。该试验的完善促成了新行业标准《家具实木胶接件剪切强度的测定》的修订,力求通过更为科学的测定方法和评价指标更好地确保家具产品的质量。     

一组家具和木制品标准和检测方面信息

安徽省《学生公寓多功能家具生产和安装质量安全验收规范》出台，《辽宁省实木家具市场规范》正式出台，浙江省地方标准《户外休闲家具安全技术要求及试验方法》审定会召开，《深色名贵硬木家具》轻工行业标准修订审定会召开，木门认证机构推出CTC产品质量认证……     

非结构用臭冷杉集成材的性能研究

使用常温快速固化的改性醋酸乙烯作为集成材胶黏剂。并通过设计正交试验,通过改变不同压力、时间、固化剂用量三因素制作出9组试件,经测定其压缩剪切强度,并分析得出对长白山臭冷杉结构集成材的压剪强度影响主次关系为：时间﹥MDI用量﹥压力。实验表明,臭冷杉结构集成材的最佳工艺条件为时间为2h,压力为3MPa,MDI用量为20%。该条件下制备的集成材具有良好的胶接性和耐水性,符合国标对结构集成材的要求。     

冷榨核桃饼基木材胶黏剂的制备及性能研究

为了提升蛋白基胶黏剂的耐水性,以支化聚合物(PEI)为改性剂,以160目核桃饼粉为原料,在碱性条件下进行热解处理后,考察不同反应条件及PEI添加量对胶合板胶接强度的影响。并利用差示扫描量热仪(DSC)对不同PEI添加量下胶黏剂的固化特征进行了测试,借助FT-IR分析对固化前后基团的变化进行了表征。结果表明,PEI添加量30%～40%、预处理温度90℃、预处理时间1 h条件下制备的胶黏剂可满足Ⅲ类胶合板的使用标准。总体而言PEI添加量越多,胶黏剂体系的固化峰值温度越高,说明体系中物质间的化学反应程度越高,越有利于胶接强度的提升。在胶黏剂固化过程中,PEI中的活性氨基和亚氨基与核桃饼热解液蛋白质分子中的羧基和氨基之间发生了化学键合,有助于体系胶接强度的提升和耐水性的改善。因此,PEI的使用可有效提升核桃饼基木材胶黏剂的耐水性和胶接强度。     

国家林业公益性行业科研专项重大项目——“实木家具用低质材提质加工技术研究与示范”项目启动

5月17日,＂实木家具用低质材提质加工技术研究与示范＂项目在北京正式启动。其中,人工林杨木压缩增强加工技术、人工林杨木浸渍增强加工技术、改性材专用无醛胶黏剂制备与胶接技术、改性杨木饰面技术以及实木家具设计与制造技术,是实木家具用低质材提质加工技术研究与示范项目需要突破的关键,进而实现人工林低质材代替优质珍贵木材用于实木家具制造。     

今年需完成制定和修订的家具标准计划项目

2010年年底国家标准委、国家工业和信息化部批准立项制定和修订的标准计划项目,包括以下53项标准。1国家标准(20项)《玻璃家具通用技术条件》(制定)、《家具中挥发性有机物释放量的测定排放试验室法》(制定)、《可拆装家具拆装技术要求》(制定)、《塑料家具通用技术条件》(制定)、《竹制家具通用技术条件》(制定)、《电动密集书架技术条件》(修订)、《家具表面漆膜附着力交叉切割测定法》(修订)、《家具表面漆膜光泽测定法》(修订)、《家具表面漆膜厚度测定法》(修订)、《家具表面漆膜抗冲击测     

山东省家具产业的原材料与产品特点研究

山东省家具产业主要用红橡。白橡等阔叶树材和樟子松、辐射松等针叶树材制造实木家具,常用纤维板、刨花板、胶合板、细木工板为基材、天然薄木为饰面材料生产板式家具,多用三聚氯胺改性脲醛树脂胶和白乳胶等胶粘剂作为胶接材料,用聚氨酯漆、聚酯漆等溶剂型涂料涂饰家具。家具产量逐年小幅递增,销售以国内市场为主、国际市场为辅。企业应依靠工艺创新和技术创新提高木材出材率,使用环保型胶粘剂和涂料改善家具环保性能,强化文化创新增加家具附加值,实现家具产业健康持续发展。     

PVC/木粉复合材料胶接件拉伸剪切强度的研究

参照国家标准GB/T 7124-2008《胶粘剂拉伸剪切强度的测定（刚性材料对刚性材料）》检测PVC/木粉复合材料胶合试件的拉伸剪切强度,发现：PVC/木粉复合材料胶合试件的断裂均发生在粘接区域外的复合材料本身,因而无法比较胶黏剂的粘接强度。为了能比较胶黏剂胶接接头的粘接强度,实验中将GB/T 7124-2008中规定的试件的厚度从1.6 mm加大至4mm。实验结果表明：采用环氧树脂粘接的PVC/木粉复合材料的拉伸剪切强度值高于用J-39丙烯酸酯胶黏剂粘接的复合材料的拉伸剪切强度。     

《家具表面软/硬质覆面材料剥离强度的测定》行业标准解读

随着科学技术的发展,应用于家具及其他木制品表面的覆面材料种类越来越多,要求越来越高。而行业标准QB/T 3655-1999《家具表面软质覆面材料剥离强度的测定》和QB/T 3656-1999《家具表面硬质覆面材料剥离强度的测定》是于1999年发布实施至今,其适用范围、有些技术要求已不能满足行业需要。为此,对这两个行业标准的修订过程和新近发布实施的QB/T 4448-2013《家具表面软质覆面材料剥离强度的测定》和QB/T 4449-2013《家具表面硬质覆面材料剥离强度的测定》标准的主要技术内容进行了解读,并就如何正确认识和使用这两项新标准提出了建议     

戊二醛改性核桃饼粕胶接体系的性能评估

旨在以核桃饼粕为原料制备具有优良耐水性能的蛋白基胶黏剂,以不同用量的戊二醛为改性剂制备了一系列改性核桃饼粕胶接体系,测定其基本性能、固化特征、胶合强度以及结构特征,以此评估戊二醛改性核桃饼粕胶接体系的性能。结果表明：戊二醛用量越大,改性核桃饼粕胶接体系的黏度总体越大;改性核桃饼粕胶接体系均可在160 ℃以下完成交联固化,尤以戊二醛用量为2.5%时的固化峰值温度最低(123 ℃);经63 ℃热水处理后胶合板样品的胶合强度最大可达0.87 MPa,胶接体系具备优异的耐水性;傅里叶红外光谱(FT-IR)分析表明戊二醛中醛基(—COH)可与核桃饼粕中羧基(—COOH)和氨基(—NH2)之间形成良好的交联,为胶接体系胶合强度及耐水性提供了重要支撑。综上,戊二醛用量为2.5%时所制备的核桃饼粕胶接体系性能较优。     

Structural bonding of ash (Fraxinus excelsior L.): resistance to delamination and performance in shearing tests

The utilization of ash (Fraxinus excelsior L.) allows for a significant enhancement of the load-bearing capacity in structural laminated products. However, such applications fundamentally require high-strength and durable bonds between lamellas and in finger joints. Therefore, the aim of the present survey was to evaluate ash bondings in terms of resistance to delamination (EN 302-2) and shear performance (EN 392). Investigations were performed with five adhesives: phenol-resorcinol-formaldehyde (PRF), melamine-urea-formaldehyde (MUF-1, MUF-2), polyurethane (PUR), emulsion polymer isocyanate (EPI) and varying closed assembly times as key bonding parameter. For all tested adhesives and closed assembly times, the shear test showed high wood failure percentages and bond strength values that compare to solid ash. In contrast, for resistance to delamination, significant differences were found between the adhesives as well as between closed assembly times, with improving resistance to delamination for increasing closed assembly times. The best performance was determined for the PRF-adhesive and long closed assembly times. However, standard requirements for resistance to delamination could not be met by any of the adhesives. The resistance to delamination showed no correlation with the shear performance for any of the adhesives. Microscopic examination of the bonded joints revealed that both the penetration behavior of the adhesives and glueline thicknesses clearly correlated with the closed assembly time.     

Enhanced bonding strength of heat-treated wood using a cold atmospheric-pressure nitrogen plasma jet

In this work, the bonding strength enhancement of heat-treated wood using a cold atmospheric-pressure nitrogen plasma jet for several lengths of treatment time was investigated. The enhancement of bonding strength was assessed by measurement of the contact angle of aqueous adhesive and water borne finish along with determination of compressive shear strength of wood samples bonded with an aqueous adhesive and pull-off strength of a water borne finish coating on wood samples. Additionally, the elemental composition and crystallinity index of the heat-treated wood surface were characterized using X-ray photoelectron spectroscopy and X-ray diffraction. As expected, the measurements demonstrated that contact angle decreased after atmospheric-pressure nitrogen plasma jet treatment, and the optimal treatment time was 100 s. X-ray photoelectron spectroscopy shows that hydrophilic groups such as C=O, OH, and COOH appeared on the surface of the HW. The atmospheric-pressure nitrogen plasma jet treatment had a positive effect on the crystallinity of heat-treated wood because of a slight degradation of hemicelluloses. Increasing the bonding strength of heat-treated wood is beneficial for broadening the fields of its applications.     

人工林杉木胶合工艺优化研究

采用SAS全因子试验设计,研究了胶粘剂类型、涂胶量、单位压力、加压时间和胶合面纹理五个因子对人工林杉木木材胶合性能的影响,并对其胶合工艺进行了优化。研究结果表明:胶粘剂类型对杉木木材常态胶合剪切强度和木破率的影响不显著,但是老化处理后API和PF的胶合剪切强度和木破率比PVAc和UF的要高;在以API为胶粘剂时,涂胶量、单位压力、加压时间和胶合面纹理对杉木胶合剪切强度和木破率的影响显著,优化的胶合工艺为涂胶量250g/cm2,单位压力1.5 MPa,加压时间50 min和胶合面纹理为弦切面-弦切面。     

柞木弦／径切面胶合强度的试验研究

对柞木木材自身弦／径面强度及其水性高分子异氰酸酯(API)胶粘剂胶合试件弦／径面胶接强度进行了研究。结果表明:柞木木材API胶粘剂弦／径面胶合试件常态压缩剪切强度存在着差异;柞木径切面API胶合试件的常态压缩剪切强度比弦切面胶合试件的常态压缩剪切强度高;径切面API胶合试件的常态压缩剪切强度是弦切面的1.22倍;而柞木弦、径面API胶合试件的反复煮沸压缩剪切强度没有显著性的差别。柞木木材本身弦／径面顺纹抗剪强度试验结果表明:柞木木材径向的顺纹抗剪强度为14.41MPa,柞木木材弦向的顺纹抗剪强度为14.97MPa,尽管弦径向间差别不大,但经t-检验证明:柞木的弦／径向间顺纹抗剪强度有显著性的差别,柞木的径向顺纹抗剪强度比弦向顺纹抗剪强度小。     

家具甲醛释放量检测标准不确定度评定方法

根据GB18584—2001《室内装饰装修材料木家具中有害物质限量》标准规定,按照家具产品甲醛检测实际过程,从理论和实践两方面分析了影响检测结果的因素。介绍了如何确定甲醛检测不确定度分量,如何建立不确定度评定数学模型,以及怎样计算测量合成标准不确定度和应用注意事项。     

The wettability and bonding performance of densified VTC beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst.) bonded with phenol–formaldehyde adhesive and liquefied wood

The influence of viscoelastic thermal compression (VTC) on surface wettability and bonding performance of wood was evaluated. Low quality beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst.) were densified with the VTC process to different degrees of densification. Control and densified strips were bonded with phenol–formaldehyde (PF) adhesive and liquefied wood (LW). Shear strength of bonded assemblies was determined after 1 week of conditioning at 20 °C and relative humidity of 65 %. Wettability was determined on the basis of the contact angle of water, PF adhesive, and LW using the Wilhelmy method. Results showed that densification of beech and spruce wood did not significantly affect the shear strength of specimens bonded with PF adhesive. In beech assemblies bonded with LW shear strength decreased significantly with increased density, whereas in bonded spruce specimens decrease of shear strength was not significant. It was found that degree of densification and bonding process used in the study were not appropriately chosen for spruce wood specimens, since major deformations after the bonding process occurred. Wettability changed significantly after densification. Contact angle of water and LW increased after densification, whereas contact angle of PF showed inverse trend and decreased after VTC process. Furthermore, the degree of densification had a minor effect on the wettability.     

Evaluation of strength properties of parallel splint lumber (PSL) and its comparison with laminated veneer lumber (LVL), rubber wood and teak

Heavea brasiliensis ) and an exterior type of adhesive were evaluated in air-dry condition. Block shear tests were also carried out in wet and dry condition. Comparisons of these strength values were made with those of laminated veneer lumber (LVL), solid rubber wood and standard teak. The results show that PSL has slightly lower values of strength properties compared to teak, solid rubber wood and quite inferior ones to those of LVL. On the basis of the data obtained in the present study, PSL made from rubber wood can be utilised as a structural material for different purposes like door and window frames, rigs and trusses.     

Evaluation of strength properties of parallel splint lumber (PSL) and its comparison with laminated veneer lumber (LVL), rubber wood and teak

( Heavea brasiliensis ) and an exterior type of adhesive were evaluated in air-dry condition. Block shear tests were also carried out in wet and dry condition. Comparisons of these strength values were made with those of laminated veneer lumber (LVL), solid rubber wood and standard teak. The results show that PSL has slightly lower values of strength properties compared to teak, solid rubber wood and quite inferior ones to those of LVL. On the basis of the data obtained in the present study, PSL made from rubber wood can be utilised as a structural material for different purposes like door and window frames, rigs and trusses.

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木家具表面耐香烟灼烧性能测定

木家具表面耐香烟灼烧性能是木家具是否合格的一项重要的理化性能指标,也是近几年木家具质量问题比较突出的项目。一些耐香烟灼烧差的家具漆膜遇香烟高温灼烧后,漆膜涂层容易出现脱落状黑斑、裂纹、鼓泡现象,导致家具无法使用。为了研究造成家具表面耐香烟灼烧项目合格率偏低的原因,笔者依据GB/T 3324-2008《木家具通用技术条件》和GB/T 17657-1999《人造板及饰面人造板理化性能试验方法》要求对不同厂家、不同工艺制作的家具表面耐香烟灼烧能力进行了测定和分析。结果表明,油漆种类、油漆工艺对家具表面耐香烟灼烧能力有显著影响。另外,木家具经贴装具有耐磨、耐灼烧性能的浸渍膜纸后,具有较高的耐灼烧性,可应用于干燥高温领域。     

实木家具装配模型的建立及信息提取

家具产品在成批装配之前,一般需要制造实物样机进行装配试验,这一过程中如果发现问题就要进行再制造。为了有效地缩短时间,提高产品装配效率,可以把虚拟装配技术应用到家具行业中,即在家具生产制造之前进行可装配性检查并规划出合理的装配方案。装配建模及信息提取技术是进行虚拟装配的前提和基础,决定着虚拟装配最终实施的质量和效率。以Solid Works软件为工具,以实木餐椅为例,从装配模型入手,分析了装配分层信息模型的结构,归纳了装配建模的关键步骤并总结了整体建模思路。在此基础上利用VB对Solid Works进行二次开发,提取装配模型的信息,形成装配序列和路径规划所需要的信息数据,以期更好的为虚拟装配服务。