生物胶乳替代丁苯胶乳在预涂涂料中的应用

研究了生物胶乳取代一定比例的丁苯胶乳（生物胶乳和丁苯胶乳的比例依次为0∶10、1∶9、2∶8、3∶7、4∶6）对预涂涂料性能的影响,并分析了其对涂布铜版纸成纸指标的影响。结果显示：生物胶乳能部分替代丁苯胶乳在铜版纸预涂涂料中使用,但随着生物胶乳替代丁苯胶乳比例的增大,涂料的粘度有所降低,同时涂料的失水值有所提高,当生物胶乳和丁苯胶乳的比例为4∶6时,涂料的失水值上升了约21%;同时随着生物胶乳替代丁苯胶乳比例的增大,涂布铜版纸成纸的强度等主要指标基本上呈逐渐下降的趋势。在保证涂布纸主要指标的前提下,生物胶乳最多能替代30%的丁苯胶乳。     

涂布纸工业中的羧基丁苯胶乳

从1960年开始,羧基丁苯胶乳已开始被应用于纸和纸板的涂布.今天,由于其优良的性能和经济性,羧基丁苯胶乳被涂布纸工业大量和广泛地采用.纸张和纸板涂布的主要原因是改进其外观并创造一个适合于印刷的表面.纸的涂布改进了平滑度、光泽度和不透明度,并使得表面具有均一的油墨接收性和高的油墨光泽度.胶乳较之蛋白和淀粉胶粘剂有很多优越性.这些优越性包括高固含量而低粘度,对涂料的粘度影响很小;在高固含量下具有优良的上机运行性;高纸张光泽度和油墨光泽度;高纸张表面强度.本文综述了胶乳对纸张性质的影响,这些内容不论对涂布纸工厂和印刷厂都是很重要的.     

Purification and some properties of sodom-apple latex proteinases

Two thiol-activated proteinases with isoelectric points (pIs approximately 9–9·5) were purified from sodom-apple latex by chromatography on Q-Sepharose and Superdex 200. Proteinase I had an estimated molecular weight of approximately 25 000 and proteinase II one of about 30 000. The proteinases degraded casein and azocoll, proteinase I having a lower specific activity than proteinase II. Proteinase I was most active at pH 8–10, with the optimum at about pH 8. Proteinase II was most active at pH 6–8, with the optimum at about pH 7.     

Efficacy of a latex teat sealer

In the first of two experiments, efficacy of a latex teat sealer product was tested under field conditions on 32 cows that had one side of the udder dipped with the test product and the other left as the control. Number of new coliform, staphylococcal, or streptococcal infections in treated quarters was not reduced from controls. In a second experiment, effectiveness of this product as a protective sealer was investigated on six cows dip challenged with a broth containing 1 million Escherichia coli/ml. On sealed teats the challenge was applied on top of the dried film. The challenge organism was recovered from 33% of treated quarters and 42% of control quarters 6 h after exposure. Organisms were recovered from none of the quarters by 31 h postchallenge.     

有机硅改性聚丙烯酸酯乳液的研究

以双端丙烯酰氧基聚醚聚硅氧烷(diAp-PDMS)和双端丙烯酰氧基丙基聚硅氧烷(diAOp-PDMS)为有机硅改性单体,通过半连续预乳化方法,分别改性聚丙烯酸酯乳液,并应用于涂料印花.研究了不同有机硅改性单体对改性胶膜的影响,并测定了2种改性乳液涂料印花的性能.结果表明:采用有机硅改性聚丙烯酸酯胶膜具有较低的吸水率和较高的断裂功,涂料印花织物具有较好的色牢度和柔软性.与双端丙烯酰氧基聚醚聚硅氧烷改性聚丙烯酸酯相比,双端丙烯酰氧基丙基聚硅氧烷改性聚丙烯酸酯胶膜具有较好的疏水性和拉伸性能,相应地,涂料印花具有较好的耐湿摩擦牢度.     

Research Watch: Airborne latex particles

Health.     

酶解木薯淀粉胶黏剂的制备及其应用

以木薯淀粉为原料,甘油为塑化剂,经α-淀粉酶水解,碳酸锆铵交联后,得到酶解淀粉胶黏剂,并将其应用于纸张涂布。结果表明,淀粉乳浓度为50%,甘油用量15%,酶用量0.075%,得到的酶解淀粉胶乳具有较好的黏结性能,取代20%SBR胶乳时,涂布纸光泽度、平滑度和白度均优于100%SBR胶乳涂布纸,同时可保持涂层的表面强度。     

复合型无氟聚丙烯酸酯乳液的制备及其防水性能

针对含氟拒水整理剂存在生物毒性、耐久性较差等问题,合成了一种聚丙烯酸酯型无氟防水剂。将丙烯酸十八酯(SA)分别与丙烯酸乙基己酯(2-EHA)和甲基丙烯酸环己酯(TMCHMA)进行细乳液聚合,制备了成膜等性能不同的2种SA共聚物胶乳;2种胶乳经复合后用于织物的无氟防水整理,借助原子力显微镜观察了复合胶乳涂膜的表面形貌,研究了复合比例及用量对整理织物表面结构以及防水性的影响。结果表明：与2-EHA共聚可提高胶乳的成膜性,而TMCHMA的引入则可增强胶乳的保形性;2种胶乳复合后,在整理后的织物表面形成微纳疏水结构,整理织物的防水性能显著提升,其静态接触角最高可达152°,防水等级达到5级,经50次耐磨损测试后仍保持良好的疏水性能。     

疏水缔合乳液聚合印花增稠剂的制备及性能表征

以自制的带疏水链的聚氧乙烯醚甲基丙烯酸酯作为功能单体,采用半连续乳液聚合反应法,合成出一种无有机溶剂的疏水缔合型乳液聚合印花增稠剂,并对其结构和性能进行表征.结果表明,自制疏水缔合乳液聚合增稠剂的碱增稠能力和耐电解质性能优异.     

天然乳胶产品的鉴定以及风险监控

随着乳胶产品的广泛应用,如何鉴定乳胶中的天然成分以及对毒害化学物质的风险监控成为关注的焦点.采用红外光谱法和水提蛋白质法,利用天然乳胶中所含蛋白质的特征,可准确、快速地鉴定天然乳胶与合成聚异戊二烯乳胶.同时分析了乳胶生产过程中存在的危害化学物质风险及检测限量.     

Characterization of associated proteins and phospholipids in natural rubber latex

Non-rubber components present in natural rubber (NR) latex, such as proteins and phospholipids, are presumed to be distributed in the serum fraction as well as surrounding the rubber particle surface. The phospholipid-protein layers covering the rubber particle surface are especially interesting due to their ability to enhance the colloidal stability of NR latex. In this study, we have characterized the components surrounding the NR particle surface and investigated their role in the colloidal stability of NR particles. Proteins from the cream fraction were proteolytically removed from the NR latex and compare to those from the serum fractions using SDS-polyacrylamide gel electrophoresis revealing that both fractions contained similar proteins in certain molecular weights such as 14.5, 25 and 27 kDa. Phospholipids removed from latex by treatment with NaOH were analyzed using (1)H-NMR spectroscopy and several major signals were assignable to -(CH(2))(n)-, -CH(2)OP, -CH(2)OC═O and -OCH(2)CH(2)NH-. These signals are important evidence that indicates phospholipids associate with the rubber chain. The colloidal behavior of rubber lattices before and after removal of protein-lipid membrane was evaluated by zeta potential analysis and scanning electron microscope (SEM). The lowest zeta potential value of NR particles was observed at pH 10, consequently leading to the highest stability of rubber particles. Additionally, SEM micrographs clearly displayed a gray ring near the particle surface corresponding to the protein-lipid membrane layer.     

A preliminary investigation into the possible transfer of latex allergens from latex protein containing materials in contact with food

Commercial FITkits^? ELISAs for four major latex allergens (Hev b1, Hev b3, Hev b5 and Hev b6.02) were modified to enable semi‐quantitative measurement of the allergens at low concentrations (5–10 ng mL^?1). The recovery of latex allergens from foods spiked with a latex cold seal adhesive was determined using one sample from each of the following food groups: confectionery/chocolate, fruit/vegetables, fruit juices, ice cream, cheese, meat and pastry. Cheese and pastry samples proved problematic owing to their high fat content. When these samples were excluded, the overall recovery for Hev b6.02 was 98 ± 12% (mean ± SD) and for Hev b5 80 ± 17%. In general, Hev b1 and Hev b3 allergens were difficult to extract from all the foods tested. Of 21 food contact materials tested, the assays detected one or more latex allergen in seven of the samples. Commercial foods associated with these wrappers were tested to determine possible transfer of the allergens to the foods. Transfer of Hev b3 or Hev b5 to food was identified at low levels in three samples, with the highest level being found in a chocolate biscuit (approximately 17 ng mL^?1 extract). Copyright © 2006 Society of Chemical Industry     

无皂苯丙乳液的制备工艺研究

通过将反应型乳化剂DNS-86与DNS-1035复配,引入交联单体丙烯酸羟乙酯(HEA),合成了一系列性能优异的无皂苯丙乳液粘合剂.结果表明:固含量为(45±2)%,单体转化率较高,乳液凝胶率较小,且乳液离心稳定性、储存稳定性、稀释稳定性、电解质(Ca2+)稳定性和酸碱稳定性均良好;采用无皂苯丙乳液印花的织物耐干、湿摩擦色牢度和耐皂洗色牢度等级与市售涂料印花粘合剂相当;红外光谱(FT-IR)分析表明:优化后的苯丙乳液中没有C C双键存在,即没有反应型乳化剂的剩余,实现了无皂乳液聚合.     

端丙烯酰基聚硅氧烷合成及其对聚丙烯酸酯的改性

以双端氨丙基聚硅氧烷和双端羟丙基聚硅氧烷为原料,分别与丙烯酰氯酰化反应,合成双端丙烯酰胺基丙基聚硅氧烷(diAAp-PDMS)和双端丙烯酰氧基丙基聚硅氧烷(diAOp-PDMS),并将其用于改性聚丙烯酸酯胶乳的合成。研究了合成因素对各自产率的影响,比较了2种改性有机硅单体合成产率及其改性胶膜和涂料印花性能。结果表明:通过与丙烯酰氯发生酰化反应,双端氨丙基聚硅氧烷活性明显高于双端羟丙基聚硅氧烷。与diAOpPDMS相比,diAAp-PDMS合成产率高;改性胶膜疏水性高,断裂强度低,断裂延伸率大,断裂功略大;改性胶乳印花织物干、湿摩擦色牢度均可达到4级以上,手感柔软,其涂料印花性能总体优于diAOp-PDMS。     

丙烯酸酯皮革填充乳液的粒径及其分布

采用不同的聚合方式和预乳化工艺 ,合成了丙烯酸酯皮革填充乳液。系统研究了聚合方式、复合乳化剂的用量和配比、聚合温度、官能团单体含量和搅拌强度对丙烯酸酯共聚物乳液粒径及其分布的影响     

非石棉胶乳抄取板中的填料

对非石棉胶乳抄取板中填料的功能与分类、填料的选用原则、常用填料和填料的补强机理作了简要概述,并展望了非石棉胶乳抄取板中填料的发展方向。     

The effect of dephosphorylation and succinylation on the properties of casein proteins adsorbed to the surface of latex particles

Dephosphorylation decreased the absolute zeta potential and diameters of α_S1-casein-coated latex particles. Similar effects were observed for α_S1-casein dephosphorylated prior to or after adsorption. If α_S1-casein adopts a loop arrangement at hydrophobic surfaces, then it appears that dephosphorylation causes the loop to move closer to the surface. Dephosphorylation caused a larger change for particles coated with α_S1-casein than β-casein, whereas small changes were observed for κ-casein, consistent with the phosphorylation levels of these caseins. Succinylation increased the absolute value of zeta potential and the diameters of α_S1-casein-coated latex particles. A higher level of succinylated α_S1-casein was required to saturate the particle surface. It is proposed that succinylated α_S1-casein has the C-terminal region adsorbed to the particle surface and N-terminal region extending from the surface as a hair. Results of this study help explain the effect of dephosphorylation and succinylation on the functional properties of the caseins, particularly in stabilising emulsions.     

双端丙烯酰氧基丙基聚硅氧烷改性聚丙烯酸酯合成及性能

采用双端丙烯酰氧基丙基聚硅氧烷改性聚丙烯酸酯,并应用于涂料印花。研究了改性单体加入方式及用量对改性乳液和胶膜性能的影响,测定了改性聚丙烯酸酯胶乳、胶膜以及其涂料印花性能,并与双端丙烯酰氧基聚醚聚硅氧烷改性聚丙烯酸酯进行了比较。结果表明：采用混合法加入有机硅改性单体,其用量为8%~10%时,乳液聚合具有较高的单体转化率和较低的凝聚率;改性胶乳粒径为62nm左右,且分布较窄;改性胶膜具有较低的吸水率和较高的断裂功,涂料印花织物具有较好的色牢度和柔软性。与双端丙烯酰氧基聚醚聚硅氧烷改性聚丙烯酸酯相比,双端丙烯酰氧基丙基聚硅氧烷改性聚丙烯酸酯胶膜具有较强的疏水性和拉伸性能,相应其涂料印花具有较好的耐湿摩擦牢度。     

田菁胶在卷烟纸中的应用试验

本文就田菁胶的浓度、温度、贮存时间与粘度的关系,田菁胶对纸张质量的影响,及其与PEO、改性淀粉的共用效果作了初步的探讨。