Sustainable Raw Materials in Hot Melt Adhesives: A Review

Hot-melt (HM) adhesives offer advantages over their contemporary water-based and solvent-based adhesives like low volatile organic compounds (VOCs), 100% solid, fast drying, setting etc. In recent years, to reduce their dependence on dwindling petroleum resources and due to the enormous use of HM adhesives in packaging areas that demand 100% recyclability, efforts have been devoted to making these formulations completely bio-based, sustainable and biodegradable. In this attempt, research and developments have been focused on using starch, modified starch, soy protein, polylactides, polyamides, lignin and vegetable oils as a partial/fully replacement to the petrochemical-based polymers. The huge amount of research going on in the field of bio-based polymers has still not reached its complete potential in the field of HM adhesives. In this review paper, HM adhesives based on sustainable raw materials namely starch, modified starch, polyamides, poly (lactic acid), soy protein and lignin are discussed.

Effect of hot-humid exposure on static strength of adhesive-bonded aluminum alloys

The effect of hot-humid exposure(i.e., 40 C and 98% R.H.) on the quasi-static strength of the adhesive-bonded aluminum alloys was studied. Test results show that the hot-humid exposure leads to the significant decrease in the joint strength and the change of the failure mode from a mixed cohesive and adhesive failure with cohesive failure being dominant to adhesive failure being dominant. Careful analyses of the results reveal that the physical bond is likely responsible for the bond adhesion between L adhesive and aluminum substrates. The reduction in joint strength and the change of the failure mode resulted from the degradation in bond adhesion, which was primarily attributed to the corrosion of aluminum substrate. In addition, the elevated temperature exposure significantly accelerated the corrosion reaction of aluminum, which accelerated the degradation in joint strength.

Lactic Acid-Sustainable Raw Material for Biodegradable Hot Melt Adhesive: Review

Currently, due to scarcity of hydrocarbon resources and the extensive use of water based, solvent based and hot melt adhesives in wood bonding in furniture industries and packaging industries that demand recyclability, compostability and bio-degradability, recently attention has been concentrated to making these formulations completely bio-based, sustainable and biodegradable. Biodegradable hot melt adhesives (HMAs) prepared from natural sources have a potential for use in furniture and packaging industries because of an increase in awareness of environmental issues, the replacement of conventional petroleum-derived hydrocarbon raw materials by renewable, biodegradable and sustainable materials has developed. In terms of environmental issues, such as climate crisis due to an increase of carbon dioxide emission, attempts have been made to produce HMAs using non-hydrocarbon resins, such as polylactic acid (PLA)-based resins, containing no petroleum as a raw material. Polylactic acid was prepared by self-condensation reactions of lactic acid or by lactide ring opening polymerisation, and used for packaging materials, sanitary pads, diapers etc., especially adhesives owing to its excellent processability and the excellent mechanical properties of its HMAs products. Therefore, recently the use of PLA materials as a substitute for non-biodegradable hydrocarbon-based polymers can be considered to be environmentally favourable. Here, we discussed the various uses of PLA as a sustainable and bio-degradable and sustainable hot melt adhesive.

Basic Study on the Evaluation of Thermoplastic Polymers as Hot-Melt Adhesives for Mixed-Substrate Joining

A selection of 22 low-melting polymers was thermally and rheologically evaluated to be used as hot-melt adhesives in mixed-substrate joining samples. The choice of polymers was based on the published melting point. It was required to include a broad variety of different polymers backbones to study the influence of the different polymers comprehensively. A tool-box of widely applicable tests was developed to judge if a thermoplastic polymer is suitable for a hot-melt adhesive application. Melting temperature (onset, peak and offset temperature) and melting enthalpy were determined using standardized methods. Rheological methods were used to characterize the shear rate dependence and the flow behavior at the application temperature. The wetting behavior of the polymers was evaluated with contact angle measurements. The adhesive strength of the most promising candidates was analyzed using the Lumi Frac-adhesion method including the failure pattern.

Evaluation on High-temperature Adhesion Performance of Hot-applied Sealant for Asphalt Pavement

In order to investigate the high-temperature performances of the asphalt pavement hot-applied sealant, as well as to reduce failures of the sealant pullout, the softening point test and the flow test（two existing methods for evaluating high-temperature performances） were conducted. It was found that both tests could not accurately reflect the adhesion performances of the sealant at high temperatures. For this purpose, the adhesion test for PSAT（pressure sensitive adhesive tape） has been taken as a reference to develop a device that is suitable for evaluating the adhesion performances, by modifying relevant test parameters according to the road conditions at high temperatures. Thirteen common sealants were tested in the modified adhesion test, softening point test and f low test. The experimental results show that no significant correlation（p〉0.05） exists between the adhesion value, softening point, adhesion value and flow value; while a significant correlation（p〈0.05） exists between the softening point and flow value. The modified adhesion test is efficient in distinguishing the hightemperature adhesion performances of different sealants, and can be used as a standard method for evaluating such performances.

聚氨酯热熔胶用预聚体的合成

以二异氰酸酯和聚醚多元醇为原料,通过定时测定—NCO的含量,确定了合适的预聚反应时间和温度,制备了聚氨酯热熔胶用预聚体。对影响预聚体合成的因素:异氰酸酯的种类、—NCO的含量、水分的含量以及预聚体的贮存稳定性等进行了探讨。结果表明,最佳预聚反应条件为80℃、2 h,—NCO含量控制在9%~10%,物料中水分质量分数低于0.05%,制备的产物性能稳定。

体育用品合成革用水性聚氨酯热熔胶研究

为顺应绿色环保理念,保障体育运动装备综合性能,优化体育用品用水性聚氨酯合成革的力学性能与粘接性能,制备环保型水性聚氨酯热熔胶以粘接、修补合成革具有非常重要的现实意义。据此,本文以甲苯二异氰酸酯、聚己二酸-1,4-丁二醇酯二醇等为原料制备了水性聚氨酯乳液,并以接枝剂甲基丙烯酸羟乙酯改性制备了体育合成革用水性聚氨酯热熔胶,同时对其性能进行了测试表征。结果发现,随着接枝剂甲基丙烯酸羟乙酯用量的增加,体育用品合成革用水性聚氨酯热熔胶拉伸强度与断裂伸长率随之增大,剥离强度与剪切强度逐步增大,水接触角逐渐增大,而吸水率明显下降,表明接枝剂甲基丙烯酸羟乙酯的掺入,可有效改善水性聚氨酯热熔胶的机械性能、粘接性能,以及耐水性与疏水性。

热熔压敏胶研究进展

本研究综述了国内外SIS基热熔压敏胶和聚氨酯热熔压敏胶的研究进展,阐述了二者的优缺点、改性方法(如聚合改性、物理共混改性、化学改性)以及研究应用领域(如金属粘接、物流标签、建筑防水材料和医用胶粘剂等)进展,并对SIS基热熔压敏胶和聚氨酯热熔压敏胶的未来发展方向做了展望。

胶合板用高温花生粕和低温花生粕蛋白基胶黏剂的制备与表征

[目的]以高温花生粕(HPM)和低温花生粕(CPM)为试验原料,通过变性交联提高胶黏剂的胶接性能和耐水性,为花生粕蛋白基胶黏剂的进一步实际应用提供参考。[方法]采用尿素(U)变性和聚酰胺多胺环氧氯丙烷(PAE)树脂交联两步法制备HPM和CPM蛋白基胶黏剂,并比较其在胶合强度、黏度、官能团、热性能和微观形貌方面的差异。[结果]与未变性交联的HPM和CPM胶黏剂相比,变性交联后HPM和CPM胶黏剂制备的杨木胶合板干态胶合强度分别提高134.1%和111.4%,湿态胶合强度分别满足国家标准Ⅰ类和Ⅱ类胶合板要求;变性交联后HPM与CPM胶黏剂黏度分别提高101.5%和70.5%,热分解温度分别提高至316.44和307.57℃,且HPM制备的胶黏剂表面最紧密。[结论]变性交联后HPM胶黏剂的胶合强度、耐水性优于CPM胶黏剂,HPM比CPM更适宜作胶黏剂原料。

乙烯基三乙氧基硅烷(VTES)改性APAO-V基热熔胶及其性能研究

使用乙烯基三乙氧基硅烷(VTES)对聚α-烯烃(APAO)基热熔胶进行接枝改性,制备了高粘接强度、耐溶剂性、耐热性稳定的反应型聚α-烯烃-乙烯基三乙氧基硅烷(APAO-V)基热熔胶。探究了不同质量分数下VTES改性APAO后对所制备热熔胶体系各性能的影响,从而确定最佳配比。研究结果表明:(1)FT-IR曲线表明VTES发生水解进行自交联,VTES改性APAO成功;XRD衍射曲线表明VTES接枝APAO并未对其结晶形态产生影响。(2)当VTES的质量分数为8%时,VTES改性APAO基热熔胶的软化点、旋转黏度均达到最大值,分别为147.7℃、7025 mPa·s,APAO基热熔胶热稳定性能最好。(3)使用8%VTES改性APAO所制备的反应型APAO-V基热熔胶,改性后热熔胶的粘接强度在常温、高温(60℃)以及低温(-20℃)状态下均有提升,其中常温下粘接提升效果最好,剥离强度提升了15.0 N/cm。改性后热熔胶在浸水28 d后剥离强度仍能达到22.3 N/cm。(4)使用8%VTES改性APAO所制备的反应型APAO-V基热熔胶,比较热熔胶对4种不同塑料基材(PE、PVC、PP和ABS)的单搭接剪切强度,改性后APAO所制备的热熔胶的粘接性能均有很大程度的提升。

等离子体预处理对聚氨酯/涤纶复合织物贴合牢度的影响

为防止复合纺织品在生产过程中出现脱胶现象,文章采用低温空气等离子体技术对织物的贴合面进行预处理,以提高纤维的摩擦因数和比表面积,增加环保型水性聚氨酯热熔胶在复合织物间的贴合牢度。结果表明,等离子体预处理后,复合织物经向剥离强力提高了796%;纬向剥离强力提高了1050%;经30次水洗,复合织物的经向剥离强力为15.2 N,纬向剥离强力为9.4 N,仍符合国家标准。在电压25 kV、作用时间5.5 min、作用间距2 mm的等离子体预处理条件下,复合织物的经向剥离强力达到18.3 N,纬向剥离强力达到12.6 N,贴合牢度达到最佳。因此,等离子体预处理为解决聚氨酯/涤纶复合织物贴合牢度不佳的技术问题提供了一种可行性方法,能够同时满足市场对环保和高性能纺织品的需求。

环氧大豆油木材胶黏剂的制备及其热压工艺的优化

为开发具有较强耐水性的环保可再生胶黏剂,以环氧大豆油(ESO)为原料,选用顺丁烯二酸酐(MA)为固化剂,乙酰丙酮锌〔Zn(acac)2〕为催化剂,制备ESO木材胶黏剂,同时制备了杨木胶合板,考察了MA添加量对胶黏剂性能的影响,通过DSC分析优化了催化剂添加量,对胶黏剂进行了红外光谱和TG/DTG分析,并利用正交实验对热压工艺进行了优化。结果表明:当MA添加量为27%时胶黏剂性能达到最佳;催化剂的最优添加量为3%;通过红外光谱和TG/DTG分析证明ESO与MA发生了交联固化反应;最佳热压工艺为热压温度150℃、热压时间10 min、热压压力2 MPa、涂胶量320 g/m^(2),在此条件下湿态胶合强度为1.613 MPa,符合国家规定的普通胶合板Ⅱ类板要求(≥0.70 MPa)。该胶黏剂制备方法具有简单、高效、环保等优势,是实现ESO在木材产品生产中可持续应用的一种很有前景的策略,具有很大的工业应用潜力。

半乳甘露聚糖改性制备面料用热熔胶

以聚酰亚胺热熔胶为主体,掺杂10%~50%(w)半乳甘露聚糖制备了面料用热熔胶,并研究了其性能。结果表明:半乳甘露聚糖与聚酰亚胺热熔胶制备面料用热熔胶的过程较为成功,该热熔胶的拉伸剪切强度、剥离强度、熔体流动速率、低温挠性、水气透过率及耐热氧老化性能提升,软化温度、邵氏硬度、氧气透过率等有所下降;半乳甘露聚糖含量为40%(w)时,面料用热熔胶的拉伸剪切强度达到最大,为5.7 MPa,剥离强度为1.47 N/mm,熔体流动速率为15.9 g/10 min,软化温度为76.5℃。

热牙胶充填法与冷侧方加压法在牙隐裂伴牙髓病变根管治疗中的应用效果对比

目的:对比热牙胶充填法与冷侧方加压法在牙隐裂伴牙髓病变根管治疗中的应用效果。方法:选取2019年1月—2023年12月靖江市人民医院收治的牙隐裂伴牙髓病变患者80例为研究对象,采用随机数字表法分为对照组和研究组,各40例。两组均实施根管治疗,对照组采用冷侧方加压法进行根管充填,研究组采用热牙胶充填法进行根管充填。比较两组治疗总有效率、治疗满意度、咀嚼功能、牙周状况、生活质量。结果:研究组治疗总有效率高于对照组,差异有统计学意义(P=0.034);研究组治疗满意度高于对照组,差异有统计学意义(P=0.034);治疗后,两组咀嚼效率和咀嚼测试吸光度值高于治疗前,研究组高于对照组,差异有统计学意义(P<0.05);治疗后,两组菌斑指数、软垢指数、牙龈出血指数、牙周探诊深度低于治疗前,研究组低于对照组,差异有统计学意义(P<0.05);治疗后,两组世界卫生组织生活质量测定简表评分高于治疗前,研究组高于对照组,差异有统计学意义(P<0.05)。结论:在牙隐裂伴牙髓病变患者根管治疗中,应用热牙胶充填法进行根管充填的效果优于冷侧方加压法,有助于改善患者的咀嚼功能和牙周状况,提高生活质量及满意度。

汽车内饰胶粘剂挥发性能研究

本文选取汽车内饰常用的三类胶粘剂(水性胶、热熔胶和溶剂胶)为研究对象,应用瓶子法材料气味和热脱附-气相色谱质谱分析仪联合分析不同胶粘剂的挥发性能。研究结果表明,三种内饰胶粘剂的气味性能依次为水性胶、热熔胶、溶剂胶;不同类型的胶粘剂含有不同的VOC挥发物质,对其气味影响最大的主要物质包括N,N-二甲基甲酰胺、三乙胺、2,6-二叔丁基苯酚、乙酸、2,6-二叔丁基对甲酚(BHT)和各种溶剂类物质。通过对胶粘剂挥发性能的研究,可以确定影响其挥发性能的关键物质,并为车内空气质量改善提供技术支持。

镀锌钢管环氧粉末涂层附着力的研究

简述了钢管热浸镀锌-环氧粉末复合防护涂层体系的特点,详细分析了钢管热镀锌后水冷及钝化、镀锌层表面处理对粉末涂层附着力的影响情况。分析认为,应根据镀锌层风化状态制定热镀锌水冷、钝化及表面处理流程及操作规程,建议采取清扫级喷砂清理清洁锌层表面,以获取合适的表面粗糙轮廓,改善粉末涂层附着力。

铝合金/PC-ABS GF20嵌件注塑热熔胶膜粘接性能研究

为金属/塑料复合结构用热熔胶的选择及在注塑领域的应用提供借鉴,以RS-TES0801热熔胶膜、CO-CL-0013水性热熔胶和TC204热熔胶膜为胶粘剂,制备了8014-H21铝合金板与PC-ABS GF20的嵌件注塑件。通过红外光谱法、差示扫描量热法对3种热熔胶膜的分子结构及热性能进行了表征,研究了3种嵌件注塑件的剥离强度、耐热老化、耐冷热循环冲击及防潮性能。结果表明,TC204聚烯烃热熔胶膜完全熔融温度为122.71℃;以TC204热熔胶膜为粘结剂的0.58 mm 8014-H21铝合金/PC-ABS GF20嵌件注塑件剥离强度达到了62.12 N,且耐候性能优异。

涂层功能整理织物剥离强度方法建立及影响因素探究

建立涂层织物剥离强度测试方法,主要包括对用于剥离涂层的热熔胶进行筛选、热熔胶附着工艺的探索、万能强力机剥离程序参数的设定等。考虑到涂层与织物的结合方式,通过相关的应用实验验证该方法的准确性和适用性。同时探讨涂层与织物剥离强度的影响因素,为行业内涂层与织物接触面的力学分析和相关机理研究提供参考和借鉴。

羊毛衫扭骨现象的改善研究

运用柔软性黏合剂ST310的整理,通过滚筒式烘干机烘干和平板压烫机的热压,以改善单纱在针织横机上编织的单边毛衫扭骨现象。结果表明:黏合剂ST310最佳用量是3.3%,在压力0.30 MPa和压烫时间1.8 min、压烫温度132℃下发生交联反应,在压力的加持下,纱线由圆形变成扁平状,形成立体网状薄膜使毛羽相互固着,增加纤维间的摩擦力,稳定纱线的捻度,扭骨从20.60%改善到0.56%;经处理后手感软滑,色牢度及起毛起球性能都有半级提升,顶破强力由389 N提升到412 N。

掺配高苯乙烯含量SIS对热熔压敏胶性能影响

以台橡SIS 4113作为SIS基热熔压敏胶热嵌段共聚物主体,掺配两种高苯乙烯含量SIS 4211和4411,通过熔融混合法制备SIS型热熔压敏胶。考察了不同高苯乙烯SIS掺配量变化对热熔压敏胶基础性能、黏着特性及流变性能的影响。研究结果表明:(1)随着掺混4211及4411比例的提高,热熔压敏胶的黏度降低、软化点升高,且掺混4411效果变化尤其明显,对于黏着性能、高温持粘性、剪切破坏温度均明显提升。(2)掺混4211的环形初粘力、180°剥离力稍有波动;而掺混4411对润湿性能影响较大,环形初粘力及180°剥离力均有明显降低。(3)流变曲线显示,掺混比例升高后,玻璃化转变温度(T_(g))点及流动点逐渐升高,储能模量明显升高,与高温持粘测试结果对应。