Search

Illicit drug use causes over half a million deaths worldwide every year. Drugs of abuse are commonly smuggled through customs and border checkpoints and, increasingly, through parcel delivery services. Improved methods for detection of trace drug residues from surfaces are needed. Such methods should be robust, fieldable, sensitive, and capable of detecting a wide range of drugs. In this work, commercially produced paper with a pressure-sensitive adhesive coating was utilized for the collection and analysis of trace drug residues by paper spray mass spectrometry (MS). This modified substrate was used to combine sample collection of drug residues from surfaces with rapid detection using a single paper spray ticket. The all-in-one ticket was used to probe different surfaces commonly encountered in forensic work including clothing, cardboard, glass, concrete, asphalt, and aluminum. A total of 10 drugs (acetyl fentanyl, fentanyl, clonazolam, cocaine, heroin, ketamine, methamphetamine, methylone, U-47700, and XLR-11) were evaluated and found to be detectable in the picogram range using a benchtop mass spectrometer and in the low nanogram range using a portable ion trap MS. The novel approach demonstrates a simple yet effective sampling strategy, allowing for rapid identification from difficult surfaces via paper spray mass spectrometry.

Paper spray mass spectrometry has been demonstrated to be promising for direct analysis of therapeutic drugs in dried blood spots (DBS); however, the strong hydrogen bond and van de Waals interactions between paper substrate and analytes containing polar functional groups (e.g., therapeutic drugs) affect greatly the elution behavior and analysis sensitivity of compounds of interest during paper spray. Herein, we developed a one-sided ZrO2 coated paper substrate through a facile vacuum filtration approach using commercial ZrO2 particles as coating material and soluble starch as adhesive agent. Owing to the unique surface properties, as-prepared ZrO2 paper substrate has been shown to have excellent performance for analysis of therapeutic drugs in DBS during paper spray mass spectrometry. In contrast to original cellulose paper substrates, improvements of 43-189-fold in lower limit of quantitation (LLOQ) were obtained for the tested drugs using ZrO2 coated paper for paper spray. In comparing with the previously reported grade SG81 paper and one-sided silica coated paper, the LLOQs of the tested drugs with as-prepared ZrO2 paper decreased 1.5-16.5-fold relative to those from the above two, revealing that ZrO2 coated paper is a good candidate for paper spray in high sensitivity analysis of therapeutic drugs in DBS.

The purpose of this study was to evaluate the feasibility of using highly filled powders as electrostatically applied paper coatings. Powders prepared by two different methods were suitable for electrostatic deposition and they attached to the paper surface with a grounded backing. Pressing at elevated temperatures turned out to be a crucial process step for improving the adhesive and cohesive strengths of the powder coating layer on paper. Limited mechanical interlocking with the base paper and an uneven pressure profile were factors impairing the surface strength of the coated paper. On the other hand, factors such as higher polymer content, higher pressing temperature, pre-heating the paper prior to coating, and increasing the number of hot roll nips increased adhesion between the coating and the base paper. Powder coatings as such had uneven thickness, and they displayed a relatively broad pore size distribution.

As one of the most abundant natural polymers in nature, polysaccharides have the potential to replace petroleum-based polymers that are difficult to degrade in paper coatings. Polysaccharide molecules have a large number of hydroxyl groups that can bind strongly with paper fibers through hydrogen bonds. Chemical modification can also effectively improve the mechanical, barrier, and hydrophobic properties of polysaccharide-based coating layers and thus can further improve the related properties of coated paper. Polysaccharides can also give paper additional functional properties by dispersing and adhering functional fillers, e.g., conductive particles, catalytic particles or antimicrobial chemicals, onto paper surface. Based on these, this paper reviews the application of natural polysaccharides, such as cellulose, hemicellulose, starch, chitosan, and sodium alginate, and their derivatives in paper coatings. This paper analyzes the improvements and influences of chemical structures and properties of polysaccharides on the mechanical, barrier, and hydrophobic properties of coated paper. This paper also summarizes the researches where polysaccharides are used as the adhesives to adhere inorganic or functional fillers onto paper surface to endow paper with great surface properties or special functions such as conductivity, catalytic, antibiotic, and fluorescence.

Sources of pulping red liquor, which is produced by acidic sulfite cooking in paper industry, consisted of lignosulphonate and polysaccharide, commonly considered as waste or byproducts and used in low value, such as surfactant and adhesive are wide and its price is low. Here a novel method for high value-added utilization of the pulp and paper industry waste for fabricating super-swelling biopolymer hydrogels is introduced. In contrast to other costly utilizations, which are needed to separate red liquor or purify hemicellulose and lignin before using, it is first time to directly utilize red liquor to prepare hydrogels without pretreatment. FT-IR, SEM, TGA and XRD are used to determine structure and morphology of hydrogels. It is excited the hydrogels fabricated from acrylic (AA) and industry waste exhibit super-swelling and slow release behaviors in water. Compared with synthetic materials, the hydrogels are at low price to be chosen as candidates for water retention agent for agriculture.

Microfluidic paper-based analytical devices (μPADs) are emerging as effective analytical platforms for point-of-care assays in resource-limited areas. Simple and cost-effective fabrication method still remains challenging on μPADs. A simple and cost-effective method for fabricating paper-based devices was presented in this work by using of dipping strategy with the recycled polystyrene in chloroform as the hydrophobic reagent. Adhesive tape was employed as mask to transfer the hydrophilic channel pattern to the paper substrate. With the single-sided adhesive tape stuck on the hydrophilic parts of the paper surface, the paper-based device was immersed in chloroform solution with dissolving recycling polystyrene for several seconds. Then the hydrophilic pattern can be achieved and all the other parts on the paper surface were hydrophobic. The adhesive tape was torn off from the hydrophilic parts. The highest contact angle value of 114° of the hydrophobic part was acquired with this simple fabrication method. By using of the sandwich-type immunoreactions and luminol-H2O2 p-iodophenol (PIP) chemiluminescence(CL) system, three cancer biomarkers were simultaneously detected in human serum samples on μPADs with the linear range of 0.05–80.0 ng·mL−1 for carcinoembryonic antigen (CEA), 5.0–80.0 ng·mL−1 for alpha-fetal protein (AFP) and 1.0–50.0 ng·mL−1 for prostate-specific antigen (PSA). The fabricating strategy with recycling polystyrene and adhesive tape provides a versatile platform for prototyping of μPADs in both developed and resource constrained region.

This article discusses the fabrication of planar and nonplanar 3D paper microfluidic circuits through the use of patterned spray adhesive application and origami techniques. The individual paper layers are held together via semi-permanent adhesive bonds without the need for external clamps. Semi-permanent bonds accommodate the repeated folding and unfolding required by complex origami device structures and allow the device to be unfolded post-use to view internally displayed results. Combinations of adhesive patterns and fluid channel widths were identified that did not prevent the fluid from traveling between layers and through the entire circuit. Further, this method was extended to nonplanar 3D paper microfluidic circuits, demonstrated via multi-fluid wicking within a modified origami peacock. Such nonplanar 3D paper microfluidic circuits are expected to offer an entirely new platform for exploring new designs and functions of paper analytical devices.

The main objective of the present work was to carry out a small theoretical practical investigation on the comparison of the adhesive Aquazol® with the present adhesives:starch and Thylose® in the technique of paper lamination that proves the effectiveness of this adhesive, as a suitable product in the lamination process, observing the data obtained in the test specimens, for its reversibility, its easy application, the change of perception and the resistance to the adhesive joint. In order to reach this goal, a bibliographic search was initially made about the different adhesives regarding the method of manual paper lamination and the different application systems. Beginning with this information, a wide variety of materials and systems were selected to carry out paper lamination tests. Fot this, a total of three adhesives, an application system and a single type of secondary support -Japanese paper- were chosen, resulting in a total of 15 different laminations. In order to compare the results that could be obtained from the different adhesives, it was decides to perform a peeling test in T. Once the tests were completed, a comparison of results was carried out along with conclusions of the advantages and disadvantages of the different adhesives and the method used, attaching summaries and visually explanatory graphs., El objetivo principal del presente trabajo era realizar una pequeña investigación teórico práctica sobre la comparación del adhesivo Aquazol® con los adhesivos actuales: almidón y Thylose® en la técnica de laminación de papel que demuestre la eficacia de este adhesivo, como un producto apto en el proceso de laminación, observando los datos obtenidos en las probetas, tanto por su reversibilidad, su fácil aplicación, el cambio de percepción y la resistencia a la junta adhesiva. Para poder llegar a tal fin, inicialmente se realizó una búsqueda bibliográfica sobre los diferentes adhesivos en el método de laminación manual de papel y los diferentes métodos de laminación manual del papel y sistemas de aplicación de los mismos. A partir de esta información, se eligieron diversos materiales y sistemas para llevar a cabo las pruebas de laminación de documentos de papel. Para ello se escogieron un total de tres adhesivos, un sistema de aplicación y un solo tipo de soporte secundario -papel japonés- de los que resultaron un total de 15 laminaciones distintas. Para poder comparar los resultados que se pueden obtener de los diferentes adhesivos, se decidió realizar una prueba de pelado en T. Una vez finalizadas las pruebas, se realizó una comparativa de resultados y unas conclusiones de las ventajas y desventajas de los diferentes adhesivos y el método empleado, adjuntando resúmenes y gráficos visualmente explicativos.

We demonstrate the use of patterned aerosol adhesives to construct both planar and nonplanar 3D paper microfluidic devices. By spraying an aerosol adhesive through a metal stencil, the overall amount of adhesive used in assembling paper microfluidic devices can be significantly reduced. We show on a simple 4-layer planar paper microfluidic device that the optimal adhesive application technique and device construction style depends heavily on desired performance characteristics. By moderately increasing the overall area of a device, it is possible to dramatically decrease the wicking time and increase device success rates while also reducing the amount of adhesive required to keep the device together. Such adhesive application also causes the adhesive to form semi-permanent bonds instead of permanent bonds between paper layers, enabling single-use devices to be non-destructively disassembled after use. Nonplanar 3D origami devices also benefit from the semi-permanent bonds during folding, as it reduces the likelihood that unrelated faces may accidently stick together. Like planar devices, nonplanar structures see reduced wicking times with patterned adhesive application vs uniformly applied adhesive.

In this technical note, we describe a facile method for one-step fabrication of paper-based microfluidic devices, by simply using commercially available permanent markers and metal templates with specific patterns. The fabrication process involves only a single step of plotting pattern in paper; it can be typically finished within 1 min. The ink marks formed in the patterned paper will act as the hydrophobic barriers to define the hydrophilic flow paths or separate test zones. Various paper devices can be created by using different templates with corresponding patterns. Transparent adhesive tape-sandwiched devices could protect their assay surfaces from potential contamination. In the proof-of-concept experiments, circular paper test zones (~3 mm diameter) were fabricated for colorimetric and quantification detection of prostate-specific antigen (PSA) as a model target, based on dot-immunogold staining assays coupled with gold enhancement amplification. Several serum specimens were additionally evaluated with this new approach and the results were compared with the commercial chemiluminescence immunoassay, validating its feasibility of practical applications. Such a one-step plotting method for paper patterning does not require any specialized equipments and skills, is quite inexpensive and rapid, and thus holds great potential to find wide applications especially in remote regions and resource-limited environments such as small laboratories and private clinics.

Corn stalk pretreated with white-rot fungus Trametes hirsute was used to produce fiberboard by hot pressing without adhesive. The moduli of rupture and elasticity of the corn-stalk-based fiberboard were increased 3.40- and 8.87-fold when bio-pretreated rather than untreated corn stalk was used. Fourier transform infra-red spectroscopy, X-ray diffraction, and chemical analysis showed that bio-pretreated corn stalk increased the mechanical properties of the fiberboard because it had more than twice the number of hydroxyl group, an 18% higher crystallinity, and twice the polysaccharide content of untreated corn stalk. Its laccase content was 4.65 ± 0.38 U/g. Corn stalk-based fiberboard production did not require adhesives, thus eliminating a potential source of toxic emissions such as formaldehyde gas.

SUMMARY Objective To evaluate, through the application of different dentin bonding systems, the influence of wetness on shear bond strength in enamel. Methods This study evaluated three etch-and-rinse adhesive systems (Scotchbond MP [used with and without primer]; Singlebond; and Prime&Bond 2.1) and two self-etching adhesive systems (Clearfil SE Bond; and Xeno IV). Flat bovine enamel surfaces were either air-dried for 30 seconds or blotted with absorbent paper after acid-etching for the conventional bonding agents or before the application of self-etching bonding agents. The resin composite EsthetX was bonded to flat surfaces that had been treated with one of the adhesives, following the manufacturer's instructions. After being stored in water at 37°C for one week, bonded specimens were broken in shear. Data were evaluated with two-way analysis of variance (ANOVA) and Student-Newman-Keuls tests (α=0.05). For comparing each condition individually, regardless of the adhesive or wetness condition, a one-way ANOVA and a Student-Newman-Keuls test (α=0.05) were applied. Results The two-way ANOVA showed significant differences among adhesive systems. An interaction effect was also observed (p Conclusion The all-in-one adhesive behaved differently depending on whether the enamel surface was dry or wet.

Enzymatic bonding methods, based on laccase or peroxidase enzymes, for lignocellulosic products such as medium-density fiberboard and particleboard are discussed with reference to the increasing costs of presently used petroleum-based adhesives and the health concerns associated with formaldehyde emissions from current composite products. One approach is to improve the self-bonding properties of the particles by oxidation of their surface lignin before they are fabricated into boards. Another method involves using enzymatically pre-treated lignins as adhesives for boards and laminates. The application of this technology to achieve wet strength characteristics in paper is also reviewed.

Short carbon fibers (SCF) were modified with oxidation and coupling treatment to improve their water-wettability and bonding properties. Four types of dispersants were studied and discussed. Short carbon fibers/plant fiber (PF) composite papers were prepared by papermaking techniques. Scanning electron microscopy (SEM) and tests to determine zeta potential, absorbance, tensile index, and conductivity were carried out to investigate the modified effect of SCF and the interfacial properties. Modification experimental results showed that the surface grooves were deepened and new superficial grooves were generated by the liquid acid oxidation. The reaction with the silane coupling agent provided higher density and more uniform distribution on the SCF surface than that of organic titanate, and it obviously increased the roughness and the absolute value of zeta potential. After modification, the hydrophilic properties and dispersion in aqueous solutions were improved, the SCFs could form a good mechanical grip with plant fibers, and the conductivity and physical strength of SCF/PF composite papers were enhanced. It was shown that there was obvious adhesive binding at the fiber overlap nodes by the SEM analysis. It was confirmed that the improvement of physical properties of composite paper can be ascribed to the interfacial enhancement.

Mechanical abrasion is an extremely simple, rapid, and low-cost method for deposition of carbon-based materials onto a substrate. However, the method is limited in throughput, precision, and surface compatibility for drawing conductive pathways. Selective patterning of surfaces using laser-etching can facilitate substantial improvements to address these current limitations for the abrasive deposition of carbon-based materials. This study demonstrates the successful on-demand fabrication of fully-drawn chemical sensors on a wide variety of substrates (e.g., weighing paper, polymethyl methacrylate, silicon, and adhesive tape) using single-walled carbon nanotubes (SWCNTs) as sensing materials and graphite as electrodes. Mechanical mixing of SWCNTs with solid or liquid selectors yields sensors that can detect and discriminate parts-per-million (ppm) quantities of various nitrogen-containing vapors (pyridine, aniline, triethylamine)., United States. Army Research Office. Institute for Soldier Nanotechnologies, United States. Defense Advanced Research Projects Agency, National Institutes of Health (U.S.) (Ruth L. Kirschstein National Research Service Award F32CA157197), National Cancer Institute (U.S.)

An off-the-shelf, moisture-responsive, acetate- backed adhesive tape is investigated as a commercially avail- able smart material for fabricating low-cost, multifunctional, humidity-responsive millimeter-scale structures. Laser ablation is used for cutting and thinning-down the tape to enhance its response. Water-submerged cantilevers show a radius of cur- vature of 3 mm or lower (for laser-thinned cantilevers). Addi- tionally, their humidity response is a function of the angle between the longitudinal axis of the cantilever and polymer orientation. A cut angled at 80 � with respect to this orientation results in a tip rotation of up to 25 � , enabling the formation of bending cantilevers with twisting behavior. The tape cantile- vers are further functionalized with magnetic nanoparticles and used to create four-finger grippers that close underwater within minutes and can sample 100 mL of liquid. A cyclic humidity monitor is also fabricated using a tape strip that walks unidir- ectionally on a ratchet-shaped surface upon exposure to humidity variations. V C 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1263-1267

Multifunctional integration is an inherent characteristic for biological materials with multiscale structures. Learning from nature is an effective approach for scientists and engineers to construct multifunctional materials. In nature, mollusks (abalone), mussels, and the lotus have evolved different and optimized solutions to survive. Here, bio-inspired multifunctional graphene composite paper was fabricated in situ through the fusion of the different biological solutions from nacre (brick-and-mortar structure), mussel adhesive protein (adhesive property and reducing character), and the lotus leaf (self-cleaning effect). Owing to the special properties (self-polymerization, reduction, and adhesion), dopamine could be simultaneously used as a reducing agent for graphene oxide and as an adhesive, similar to the mortar in nacre, to crosslink the adjacent graphene. The resultant nacre-like graphene paper exhibited stable superhydrophobicity, self-cleaning, anti-corrosion, and remarkable mechanical properties underwater.

We describe a latex wet coalescence method for gas-phase immobilization of microorganisms on paper which does not require drying for adhesion. This method reduces drying stresses to the microbes. It is applicable for microorganisms that do not tolerate desiccation stress during latex drying even in the presence of carbohydrates. Small surface area, 10–65 μm thick coatings were generated on chromatography paper strips and placed in the head-space of vertical sealed tubes containing liquid to hydrate the paper. These gas-phase microbial coatings hydrated by liquid in the paper pore space demonstrated absorption or evolution of H2, CO, CO2 or O2. The microbial products produced, ethanol and acetate, diffuse into the hydrated paper pores and accumulate in the liquid at the bottom of the tube. The paper provides hydration to the back side of the coating and also separates the biocatalyst from the products. Coating reactivity was demonstrated for Chlamydomonas reinhardtii CC124, which consumed CO2 and produced 10.2 ± 0.2 mmol O2 m−2 h−1, Rhodopseudomonas palustris CGA009, which consumed acetate and produced 0.47 ± 0.04 mmol H2 m−2 h−1, Clostridium ljungdahlii OTA1, which consumed 6 mmol CO m−2 h−1, and Synechococcus sp. PCC7002, which consumed CO2 and produced 5.00 ± 0.25 mmol O2 m−2 h−1. Coating thickness and microstructure were related to microbe size as determined by digital micrometry, profilometry, and confocal microscopy. The immobilization of different microorganisms in thin adhesive films in the gas phase demonstrates the utility of this method for evaluating genetically optimized microorganisms for gas absorption and gas evolution.

We present a novel, low-resource fabrication and assembly method for creating disposable amperometric detectors in hybrid paper-polymer devices. Currently, mere paper-based microfluidics is far from being able to achieve the same level of process control and integration as state-of-the-art microfluidic devices made of polymers. To overcome this limitation, in this work both substrate types are synergistically combined through a hybrid, multi-component/multi-material system assembly. Using established inkjet wax printing, we transform the paper into a profoundly hydrophobic substrate in order to create carbon electrodes which are simply patterned from carbon inks via custom made adhesive stencils. By virtue of the compressibility of the paper substrate, the resulting electrode-on-paper hybrids can be directly embedded in conventional, 3D polymeric devices by bonding through an adhesive layer. This manufacturing scheme can be easily recreated with readily available off-the-shelf equipment, and is extremely cost-efficient and rapid with turn-around times of only a few hours.

Plant proteins are used – for the first time – in this work as bulk binders for cellulosic fibers in paper composites. Soy bean protein and wheat gluten were denatured by two methods, namely by: urea + NaOH and by urea + NaOH + acrylamide. Addition of increased amounts of the denatured proteins resulted in a significant increase in all paper strength properties. Soy protein led, in addition, to a remarkable enhancement in opacity. The use of proteins increased kaolin retention in the paper composites, while keeping the paper strength higher than the blank protein-free paper. The results show that plant proteins are favorable than synthetic adhesives; because they are biodegradable and do not cause troubles in paper recycling i.e. they are environmentally friendly.

Major commercial bookbinding technique used today is perfect binding (or adhesive binding), originally used for paperback books. In perfect binding, adhesive is used to attach the pages of a book together and attach the book cover. One of most important criterion for adhesive binding is strength over the whole length of a book leaf. It is known that adhesion strength is function of the bond between the leaf and adhesive and total sum of material contact area. The subjects of research are physical properties of paper that have impact on different general sources of binding strength. The tests were performed with constant parameters of binding process and two chemically different types of paper.

This paper presents the results on a study to use paper mill sludge for particleboard production. Single-layer board and three-layer board, with paper sludge on the surface, were fabricated. Four levels of mixing ratios of paper sludge to wood particles (0:100, 15:85, 30:70, and 45:55) were used. The boards were produced with 3% and 4% methylene diphenyl diisocyanate (MDI), and 10% and 12% urea-formaldehyde (UF) adhesives. The bending and shear strengths, water absorption, and thickness swelling of the boards were investigated. The results indicated that the mechanical properties of the boards were negatively affected by the paper sludge amount. Overall, UF-bonded particleboards gave superior mechanical performance, water resistance, and thickness swell than MDI-bonded particleboards. The strengths of the UF-bonded board decreased much more than those of MDI-bonded board as paper sludge content increased. The three-layer boards made from 15% paper sludge with 12% UF satisfied fully the minimum requirements set by EN, ASTM D 1037-99, and ANSI A208.1 standards for general uses.

Background: Protein contact dermatitis is better known in food-service and health-care workers than in industrial workers. Cornstarch has seldom been a problem, although it can cause contact urticaria to glove powder. Objective: To present the case of a paper-bag maker who developed severe occupational (protein) contact dermatitis within two-three hours after returning to work. She lacked any evidence of urticaria and demonstrated largely negative patch-test results. Methods: Following a history of occupational exposure to a cornstarch-based adhesive, the patient was patch-tested to materials with which she had worked, which she contacted, and with which she had attempted treatment. Following patch testing, she was prick-tested to cornstarch, the principal ingredient in the adhesive. Results: Patch testing was negative except for a very mild reaction to the adhesive. Prick testing to cornstarch was more severe than the histamine control. The test site became eczematous and remained so for more than ten weeks. Avoidance of cornstarch and the adhesive was followed by clearing. Conclusion: Workup for prominent occupational contact dermatitis without urticaria may sometimes require testing for type 1 allergy.

We report a simple, low-cost and detachable microfluidic chip incorporating easily accessible paper, glass slides or other polymer films as the chip materials along with adhesive wax as the recycling bonding material. We use a laser to cut through the paper or film to form patterns and then sandwich the paper and film between glass sheets or polymer membranes. The hot-melt adhesive wax can realize bridge bonding between various materials, for example, paper, polymethylmethacrylate (PMMA) film, glass sheets, or metal plate. The bonding process is reversible and the wax is reusable through a melting and cooling process. With this process, a three-dimensional (3D) microfluidic chip is achievable by vacuating and venting the chip in a hot-water bath. To study the biocompatibility and applicability of the wax-based microfluidic chip, we tested the PCR compatibility with the chip materials first. Then we applied the wax-paper based microfluidic chip to HeLa cell electroporation (EP). Subsequently, a prototype of a 5-layer 3D chip was fabricated by multilayer wax bonding. To check the sealing ability and the durability of the chip, green fluorescence protein (GFP) recombinant Escherichia coli (E. coli) bacteria were cultured, with which the chemotaxis of E. coli was studied in order to determine the influence of antibiotic ciprofloxacin concentration on the E. coli migration.

Nach wie vor stellt die Leimdosierung wäßriger Leime an Sackbodenlegern für die Papiersackherstellung ein nicht befriedigend gelöstes technisches Problem dar. Die verbreitete manuelle Regelung der Leimdosierung durch den Maschinenführer resultiert oft in einer Überleimung der Sackböden mit negativen Folgen für die Festigkeit und die mikrobielle Stabilität der Säcke, bedingt durch den hohen Wassereintrag. Eine automatisch geregelte Dosierung des Leimauftrags setzt aber die Verfügbarkeit geeigneter, d. h. leistungsfähiger und preisgünstiger Sensortechnik voraus. Eines der Meßprinzipien, die für die Leimauftragsmessung wäßriger Leime in Frage kommen, ist die Mikrowellenabsorptionsmessung. Bereits verfügbare industrielle Mikrowellensensoren sind für den Einsatz am Sackbodenleger, bei dem eventuell bis zu 16 Meßstellen bestückt werden müssen, jedoch zu teuer. Seit einigen Jahren werden billige Mikrowellensender und -empfänger für Massenprodukte angeboten. Unter Verwendung dieser Komponenten könnte ein Leimauftragssensor zu sehr günstigen Kosten gebaut werden. Es wurde daher die Eignung dieser Mikrowellenkomponenten für die Leimauftragsmessung untersucht und ein Sensor-Prototyp für die Online-Messung des Leimauftrags am Sackbodenleger gebaut.

Bei der Herstellung von geklebten Papiersäcken wird der Klebstoff mit Klischee-Auftragswalzen auf die gefalteten und gestaffelten Oberflächen von mehrlagigen Sackböden aufgetragen. Dies geschieht intermittierend bei hohen Taktzahlen - bis zu 250 Säcke/min. Um die unebenen Flächen miteinander nicht nur fest, sondern auch dicht zu verkleben, neigen die Maschinenführer dazu, um vermeintlich sicherzugehen, den Klebstoff besonders dick aufzutragen. Dies führt, da es sich in der Regel um einen wässrigen Stärkeleim handelt, zur übermäßigen Durchfeuchtung des Papiersacks und dadurch zu seiner Schwächung. Um die Abfüllbarkeit der durchfeuchteten Säcke zu erreichen, müssen diese bei hohem Raum- und Energieaufwand u. U. mehrere Wochen konditioniert werden. Erforderlich sind dünne, gleichmäßige Klebstoffaufträge. Um der Gefahr der Unterdosierung zu begegnen, bzw. die optimale Dosierung sicherzustellen, ist eine Klebstoffauftragsregelung erforderlich. Die wichtigste Voraussetzung einer funktionsfähigen Regelung ist der Einsatz leistungsfähiger Sensoren zur Erfassung des Klebstoffauftrags im Sackbodenleger. Zwei Sensorsysteme wurden entwickelt, die berührungslos, inline und in Echtzeit die gemessenen Daten an ein Prozeßleitsystem liefern. Das physikalische Prinzip der Messung beruht auf der Absorption von Mikrowellen bei dem ersten und auf der Emission von Fluoreszenzstrahlung bei dem zweiten System. Die Konstruktion und Arbeitsweise werden dargelegt. Der vorliegende Teil 1 behandelt die Sensortechnik auf der Basis der Fluorimetrie, der Teil 2 (in Vorbereitung) die Sensortechnik auf dem Prinzip der Mikrowellenabsorption sowie die Bedingungen für die Integration der Sensoren in die Sackbodenleger.