SC纸生产的实践与探索

本文介绍超级压光纸（SC纸）的定义与质量要求以及白麓纸业生产超级压光纸的实践与体会。     

发展超级压光纸势在必行

介绍了国外超级压光纸(SC)的现状和发展趋势,提出我国发展超级压光纸势在必行.石岘白麓纸业公司新闻纸项目引进维美德公司(Valmet)带机内超压的最新一代OptiConcept造纸机,该纸机能够满足生产高档新闻纸和B级超级压光纸(SC-B)的要求.     

超级压光纸的研究现状及发展趋势

着重概述了有关SC纸的国际市场、产品等级、质量指标及生产工艺技术等方面的情况。然后介绍了当今超级压光纸的技术发展趋势,并对国内超级压光纸的市场进行了分析。     

SC纸的技术现状

本文综述超级压光纸(SC纸)的现状，技术现状中包括SC纸的原料、白度、凹版印刷性、胶版印刷性和压光，基本上都有较详细的介绍。超级压光纸作为一种高附加值纸种，应在产业强国建设中予以高度关注。     

泉林纸业10万t超级压光纸项目投产

日前，夏津泉林纸业有限公司新上10万t超级压光纸项目正式投产。近年来，现有印刷纸己不适应印刷行业发展需求．超级压光纸作为理想的替代产品，经过超级压光整饰，纸张有相当高的平滑度。     

夏津泉林10万t·a-1超级压光纸项目投产

本刊讯据有关报道,日前,夏津泉林纸业有限公司新上10万t.a-1超级压光纸项目正式投产。超级压光纸是较理想的印刷用纸,经过超级压光整饰,纸张有相当高的平滑度。泉林纸业有限公司瞄准这一商机,投资4.5亿元,新建3万m2的生产车间、仓库,购置先进设备,年生产10万t超级压光纸,可新增销售收入8.5亿元,利税5000万元。     

超级压光的纸病及解决法

纸张经超级压光后，其光泽度、平滑度、紧度得到提高，纸的厚度均匀性及外观得以改善。现把超级压光过程中产生各种问题的原因及相应的解决办法列举如下。超级压光的纸病及解决法@庄耀孔$山东济南造纸公司一厂!250012     

涂布印刷纸的整饰

涂布印刷纸张表面平滑光泽，对印刷图文清晰性非常重要，所以涂布印刷纸需经适当的压光整饰。本文就超级压光、柔性压光、刷式抛光作以下简述。1超级压光1．l涂布印刷纸经超级压光后，平滑度与光泽度都有较大提高。超级压光机与普通压光机区别仅在于超级压光机有纸粘辊。其作用机理是：当对两接触银子施加压力时．不能变形的金属辊对纸粕辊产生压力，导致纸粕辊经压区时外表壳材料塑性变形或位移。当辊子转动时，塑性变形导致纸粕银相对于金属辊产生相对运动，从而对涂布纸涂层产生抛光作用。1．2涂布印刷纸经超级压光后，虽然被压平，但局…     

Stora Enso安装新纸机调整生产

Stora Enso拟在比利时的Langerbrugge安装一台新纸机,该纸机以废纸为原料,年产40万t新闻纸/超级压光纸。届时,该公司将永久性停开2台旧纸机,这2台旧纸机分别位于Langerbrugge(生产超级压光纸)和     

软压区压光技术

１前言自从８０年代初开发了机内软压区压光整饰技术以来,这项技术的应用越来越广泛。最初这项技术仅应用于整饰要求较低和中等要求的纸种,或在软压光发明之前一般采用硬压光的纸种。今天的软压光机已经可以获得以前只能用超级压光机才能达到的压光效果。超级压光机软压...     

SC纸的市场、技术发展趋势及生产实例

概述了有关SC纸国际国内市场、产品等级、质量指标和生产工艺技术、生产实践等方面的情况。     

超级压光纸的生产工艺

SC纸具有机械浆及填料用量高、成本低、质量好等优点,随着人类对资源及环境越来越重视,SC纸在西方发达国家得到了迅速推广。探讨了SC纸的生产工艺,如SC纸的质量特点、纤维原料组成、填料种类及用量、超级压光技术等,以使造纸工作者对SC纸有进一步了解,促进我国SC纸生产的推广。     

配抄SC纸的DIP浆生产技术

传统的SC纸使用的浆料配比一般是70％～90％机械木浆（GP、PCW、TMP）及30％～10％漂白木浆。随着DIP制浆技术的发展,DIP已经成为生产SC纸的优良纤维原料。用于配抄SC纸的DIP工艺流程以碎浆、筛选、净化、浮选脱墨、热分散处理、漂白、脱水洗涤处理为主,但SC纸比新闻纸对DIP浆料的白度、尘埃和胶粘物的去除要求更高。DIP纤维配比主要取决于生产的SC纸等级。     

Drying stress and damage processes in human stratum corneum

The drying stresses that develop in stratum corneum (SC) are crucial for its mechanical and biophysical function, its cosmetic feel and appearance, and play a central role in processes of dry skin damage. However, quantitative methods to characterize these stresses are lacking and little understanding exists regarding the effects of drying environment, chemical exposures and moisturizing treatments. We describe the application of a substrate curvature technique adapted for biological tissue to accurately characterize SC drying stresses as a function of time following environmental pre‐conditioning and chemical treatment in a range of drying environments. SC stresses were observed to increase to stress levels of up to ～ 3 MPa over periods of 8 h depending on pretreatment and drying environment. A unique relationship between the SC stress and water in the drying environment was established. The effect of glycerol on lowering SC stresses and damaging surfactants on elevating SC stresses were quantified. Extensions of the method to continuous monitoring of SC stresses in response to changes in environmental moisture content and temperature are reported. Finally, a biomechanics framework to account for the SC drying stress as a mechanical driving force for dry skin damage is presented.     

Elucidation of the mechanism of enzymatic browning inhibition by sodium chlorite

Sodium chlorite (SC) is a well known anti-microbial agent and its strong inhibitory effect on enzymatic browning of fresh-cut produce has recently been identified. We investigated the effect of SC on polyphenol oxidase (PPO) and its substrate, chlorogenic acid (CA), as it relates to the mechanisms of browning inhibition by SC. Results indicate that the browning reaction of CA (1.0 mM) catalyzed by PPO (33 U/mL) was significantly inhibited by 1.0 mM SC at pH 4.6. Two PPO isoforms were identified by native polyacrylamide gel electrophoresis, and both were inactivated by SC (3.0 mM). This suggests that SC serves as a PPO inhibitor to prevent enzymatic browning. Furthermore, the effect of SC on the stability of CA in both acidic (pH 4.5) and basic conditions (pH 8.3) was studied by UV–Vis scan and LC–MS analysis. The results showed that at the presence of SC (3.0 mM), CA (0.1 mM) degraded to quinic acid and caffeic acid as well as other intermediates. Hence, the anti-browning property of SC can be attributed to the two modes of action: the inactivation of polyphenol oxidase directly and the oxidative degradation of phenolic substrates.     

From contact angle titration to chemical force microscopy: a new route to assess the pH-dependent character of the stratum corneum

Despite of its complex multicomponent organization and its compact architecture, the Stratum corneum (SC) is not completely impermeable to substances directly applied on the skin surface. A huge number of works have been dedicated to the understanding of the mechanisms involved in substance permeation by exploring deeper layers than the SC itself. Surprisingly, there is a poor interest in studies relating to interactions which may occur in the near-surface region (i.e. approximately 1 nm depth) of the SC. In this work, equilibrium proton-transfer reactions have been used as probes to define in a fundamental point of view the nature of the SC interactions with its environment. Such titration curves are investigated on 'in vitro' SC (isolated SC from abdominal skin tissue) and on 'in vivo' volar forearm (a sebum poor area). The results are discussed in term of work of adhesion and surface pKa values. Because SC can 'reconstruct' under heating, influence of the temperature on titration curves is investigated and the role of the different components is discussed. Different sigmoidal transitions were observed. Two common pKa values (pKa(1) = 4 and pKa(2) = 11.5) were clearly identified in both cases and associated to an acid-base character. By playing with the temperature of 'in vitro' SC, the 'accessibility' of polar functions was increased, thus refining the results by revealing an amphoteric character with an acid-to-base transition at pH 3.5 and two acid transitions at pH = 6.5 and pH = 11.5. Adhesion forces between an Atomic Force Microscopy (AFM) tip and a single isolated corneocyte through buffered liquid media were also investigated to better understand the role of the individual corneocytes.     

Preparation and characterization of phytosterol-loaded nanoparticles with sodium caseinate/dextran conjugates

Sodium caseinate (SC)/dextran conjugates were prepared via Maillard reaction under controlled dry-heating conditions. Moreover, the nanoparticles of phytosterols (PS) encapsulated by SC or SC/dextran were produced using the emulsion evaporation method. The encapsulation efficiency (78.81 ± 5.22%) of PS in SC/dextran nanoparticles was higher than that (73.5 ± 2.78%) in SC nanoparticles. Compared with the compact and dense structure of SC nanoparticles, SC/dextran nanoparticles existed as relatively loose aggregates. The result of differential scanning calorimetry demonstrated that the encapsulation of PS greatly decreased its crystallinity. The released rates of PS from SC and SC/dextran nanoparticles under acidic gastric conditions were 8.59% and 4.73%, respectively. After 7 h of intestinal digestion, the released rate (52.19%) of PS from SC/dextran nanoparticles was significantly higher than that from SC (32.67%) nanoparticles. Therefore, SC/dextran conjugates prepared by the Maillard reaction are more suitable to be used as wall material for the nano-encapsulation of PS.     

Location‐related differences in structure and function of the stratum corneum with special emphasis on those of the facial skin

Between the two different kinds of the skin covering the body, the glabrous skin is found only on the palmo‐plantar surface because of its rather simple function to protect the underlying living tissue with its remarkably thick stratum corneum (SC) from strong external force and friction. Thus, its barrier function is extremely poor. In contrast, the hair‐bearing skin covers almost all over the body surface regardless of the presence of long hair or vellus hair. In regard to its SC, many dermatologists and skin scientists think that it is too thin to show any site‐specific differences, because the SC is just present as an efficient barrier membrane to protect our body from desiccation as well as against the invasion by external injurious agents. However, there are remarkable regional differences not only in the living skin tissue but also even in such thin SC reflecting the function of each anatomical location. These differences in the SC have been mostly disclosed with the advent of non‐invasive biophysical instruments, particularly the one that enables us to measure transepidermal water loss (TEWL), the parameter of the SC barrier function, and the one that evaluates the hydration state of the skin surface, the parameter of the water‐holding capacity of the SC that brings about softness and smoothness to the skin surface. These in vivo instrumental measurements of the SC have disclosed the presence of remarkable differences in the functional properties of the SC particularly between the face and other portions of the body. The SC of the facial skin is thinner, being composed of smaller layers of corneocytes than that of the trunk and limbs. It shows unique functional characteristics to provide hydrated skin surface but relatively poor barrier function, which is similar to that observed in retinoid‐treated skin or to that of fresh scar or keloidal scars. Moreover, there even exist unexpected, site‐dependent differences in the SC of the facial skin such as the forehead, eyelid, cheek, nose and perioral regions, although each location occupies only a small area. Between these locations, the cheek shows the lowest TEWL in contrast to the perioral region that reveals the highest one. Moreover, these features are not static but change with age particularly between children and adults and maybe also between genders. Among various facial locations, the eyelid skin is distinct from others because its SC is associated with poor skin surface lipids and a thin SC cell layer composed of large corneocytes that brings about high surface hydration state but poor barrier function, whereas the vermillion borders of the lips that are covered by an exposed part of the oral mucosa exhibit remarkably poor barrier function and low hydration state. Future studies aiming at the establishment of the functional mapping in each facial region and in other body regions will shed light on more delicate site‐dependent differences, which will provide us important information in planning the strategy to start so called tailor‐made skin care for each location of the body.