For the last 20 years, medical silicone adhesives have set the standard as wound adhesives for sensitive, skin friendly wound dressings, recognized as advanced wound care.
This talk will present a general overview on existing advanced wound care applications, giving a special focus on future fields of medical applications.
It will show the versatility in the range of adhesive strength and tack, combined with the well-known benefits as atraumatic release and gentle adhesion. This will make it possible to expand their uses to traditional wound care applications, as plasters as well as medical-, sport-, and lifestyle tapes.
Moreover, the important role of solvent based silicone adhesives in transdermal drug release will be shown.
Of the 82,5 million German inhabitants in 2015, 19,2% (17,5 million) were 65 years or older. Until 2060 this rate will increase to 33%1. This trend cannot only be seen in Germany but also in other developed countries. In Japan e.g. already 28,1% (35,6 million) of the population is classified as seniors forecasting the future German situation2. Consequently, the medical device market will be faced with a fundamentally altered patient population in the next decades.
With increasing lifespans however, the population will become multimorbid i.e. having multiple medical conditions within a single patient increasing the demand for treatment. Undoubtably, for the latter plasters for e.g. wound-care will have an important role. With increasing age, also the skin-condition changes and becomes dry, thin, fragile and sensitive (“parchmentlike skin”). Consequently also medical plasters must be adapted to ensure save application, wearing comfort and atraumatic removal.
As observed within the last years, silicone-based skin-adhesives have become the go-to product for sensitive skin conditions for elderly patients but also for newborns. This is attributed to their smooth wearing-comfort, semi-occlusive gas- and water permeability, atraumatic/painless removal and repositionability.
This short study outlines the compatibility of SSAs with polyurethane-foils as substrate. Furthermore the MVTR (moisture-vapor-transmission-rate) of the SSA/PU combination was determined as well as the adhesion forces to common test-surfaces.
1 Population of Germany until 2060, 13. Coordinated Population Projection, Federal Statistical Office Wiesbaden, 2015.
2 Demographics in Japan: Focus Markets, Berlin Institute for Population and Development, Berlin, 2010.
The proven biocompatibility and atraumatic properties of Silicone Soft Skin Adhesives have made them a material of choice for modern dressings. With the rising incidence of chronic wounds like diabetic wounds and pressure ulcers, it is more and more important for Advanced Wound Care companies to be efficient when manufacturing and supplying their Silicone dressings to medical professionals. At the same time, it is crucial to prepare the future of Wound Care by integrating the latest innovations in material science, which will help treat these difficult wounds even better.
During the present lecture, we would like to draw attention to the future technical challenges in wound care and present Elkem Silicone’s expertise in the field of Silicone Soft Skin Adhesives. More precisely, we would like to present on which technical locks we are currently working to help wound care companies bring innovation in this field.
Here are some topics that will be addressed during the presentation:
• Suitable test methods for the performance of soft skin adhesives
• Routes for securing the adhesion over a long time while managing skin moisture
• Recent innovations in microbial detection and control
Presently, silicone adhesives are far from having developed all their potential and innovation is under way for the design of innovative products.
Abstract will be provided soon
Adhesys Medical was founded in 2013 in Aachen, has been acquired by Grünenthal GmbH in 2017 and continues to operate as a wholly-owned subsidiary of the Grünenthal Group. The company develops one-of-a-kind polyurethane-based medical adhesives for a great variety of potential application areas. The patent protected technology is unique, as it combines ease of use, strength, elasticity, biodegradability and can be applied in a wet environment.
The first product out of this platform is a topical skin adhesive indicated to close wounds of the skin such as from surgical incisions. The polyurethane-based formula gives this new topical skin adhesive a unique set of characteristics compared to the other skin adhesives, made from cyanoacrylate. This product is CE-marked under the brand name FLIX®.
The second product line based on the same technology is developed under the code VIVO and is intended for use inside the body to stop bleedings, seal wounds, shall reinforce suture lines and works in a wet environment. It is biodegradable, elastic, fast curing and fully synthetic, allowing for use in a great variety of surgical procedures and potential applications.
Our mission is to bring innovative surgical sealants into every Emergency or Operating Room to save lives, radically enhance surgical procedures and improve patient comfort and outcome.
Abstract will be provided soon
When it comes to industrial adhesives, maximizing their longevity under the aspect of minimizing costs of maintenance and repair are basically of high interest for the operator. Specifically, high-tech industries such as aeronautical, automotive or medicine are subject to very high standards in terms of quality, performance and safety.
Hence, for stakeholders of such industries it is crucial to know how repeating damage cycles affect the structural integrity of the whole structure. For that, the question that might arise is what significant residual strength and fracture-healing recovery rate at least is needed in order to prevent a total structural collapse.
To pursue such crucial issues, a novel study has been conducted for investigating the natural fracture-healing behavior of several well-established types of industrial adhesives. In doing so, an innovative test setup was applied for generating high-quality fracture analytical damage parameters, which cannot be found in any technical data sheet of adhesive manufacturers.
The remarkable findings revealed that only one type of adhesive was suitable for showing significant fracture-healing behavior. This was verified by different mechanical and fracture analytical metrics, such as adhesive bonding strength, cohesive strength and fracture resistance.
As a conclusion, this study showed that the inclusion of fracture analysis in the adhesive selection and evaluation process is crucial for maximizing their quality, performance and safety.
Keywords: adhesive safety, fracture-healing, healing efficiency, residual strength.
Over the last decades, the application of 2K-adhesives has been on the rise across various industries. With emergence of new technologies and high-end applications, the quest for more effective material and reliable dispensing systems continues. Along the process chain, the mixing systems remain a crucial element in successful application of 2K-adhesives and performance indicators such as mixing quality, pressure drop and waste volume are of central importance. As a leading manufacturer of 2K-component mixing and application systems, Sulzer Mixpac constantly develops new prediction and measurement methods to evaluate the mixing quality with increasing accuracy. Reliable prediction and measurement of mixing quality can significantly accelerate the development of new mixer or new adhesive formulations.
The article will cover various simulations and measurement techniques developed for reliable assessment of 2K adhesives and sealants mixing quality. Computational Fluid Dynamics as well as in-house developed particle tracking tools will be introduced and discussed. Different test methods developed for various materials will be also presented.
The article includes:
(1) Methods which measure the properties of the cured material (tensile test, bending test, shore hardness, TGA, DMA)
(2) Methods which visualize the spatial distribution of measured property (all optical and microscopic methods, FTIR, CT, CFD)
(3) Methods which allows an examination of the curing process over time (rheological measurement, DSC, DEA)
All prediction and measurement methods have been evaluated taking into account of pre-defined application-orientated test criteria. Similar criteria have been taken into account to categorize materials mixed with static mixers. This allows a direct correlation between material class and suitable prediction and measurement methods for those materials. As a result, a specific matrix has been generated providing recommendations which prediction and measurement methods should be used for which class of materials.
The matrix should help to facilitate the choice of the most suitable measurement method for a material to be analyzed in the future.
Abstract will be provided soon
The performance of coatings or adhesively bonded joints is often limited by a poor durability and resistance of the adherent/polymer-interface to humid environment. Organofunctional silanes may be used as environmentally friendly adhesion promotors and linked to the adherent’s surface via a sol-gel route. The quality of the preceding cleaning of the adherent as well as the processing conditions of coupling agents yield a strong effect on the performance of adhesively bonded joints. This paper presents a new surface activation method of combining cleaning by solid carbon dioxide snow-blasting (CO2 snow-blasting) and depositing of silane coupling agents in a single step process. This so called CRYOSIL®-treatment has been applied to specimen of hot-dip galvanized coil steel. The functionalization of the adherent surface after carbon dioxide snow blasting with coupling agents could be confirmed by FTIR-spectroscopy. Adhesively bonded T-peel specimen were prepared with elastic polyurethane adhesives and subjected to accelerated aging conditions. Experimental results confirm that the process stability of adhesive joining and the durability of adhesive joints can be enhanced by this new technology.
High-pressure die casting of aluminum alloys is an attractive manufacturing process for light-weight structural components in the automobile industry. Joining of high-pressure die cast aluminum components with other structural parts using adhesives is still challenging due to the inherent contamination of casting surfaces by die lubricants in the casting process. In this talk we report on chemical pre- treatment processes as state of the art in industry and laser pretreatments as alternative method for the reliable fabrication of adhesive joints. Pros’ and Cons are discussed with focus on aging stability of the surface and process parameters for an integration in serial production.
Today, the use of additive manufacturing is increasing more and more, as small series with a high geometric variety can be produced quickly and cost-effectively. Compared to conventional production by injection moulding, high costs for necessary moulding tools can be saved. A disadvantage of additive manufacturing is the limited size of the installation space and thus a limitation of the maximum component size. In order to bypass this limit, joining processes are necessary for additively manufactured components. Bonding is the most suitable joining technique here, as there is no thermal stress on the components, as is the case with welding, and no stress concentration, as is the case with screwing or riveting. In particular, the possibility of joining additive plastic components with other materials such as metals or ceramic is a major advantage of bonding technology.
Since the quality of the components in additive manufacturing differs from that of conventional manufacturing, particularly with regard to the surface structure and composition, pre-treatment and bonding processes cannot be easily transferred. For this reason, the German Plastic Center SKZ is working on an IGF project (IGF no.: 19629 N) about "Research into the influence of material- and process-related properties of additively manufactured plastic components on bonding processes to increase the bond quality".
In this project the two additive manufacturing processes for plastics laser sintering and fused deposition modeling are used. The focus of the project is on the laser sintering of PA12. The influence of different manufacturing parameters (construction directions and post-treatment processes such as glass bead blasting, vibratory grinding and chemical smoothing) and pretreatment processes (atmospheric pressure plasma and flame treatment) on the adhesive strength when using different adhesive classes (polyurethanes, epoxies, 2K-methyl methacrylates and cyanoacrylates) is investigated.
Carbon fiber reinforced plastics (CFRP) are increasingly used in aerospace and automotive applications. Beside the high strength-to-weight ratio, parts made of CFRP often show an excellent fatigue behavior and come with less corrosion problems in-service. Despite mechanical fastening, adhesive bonding is an interesting joining method for CFRP. It allows joining parts without drilling holes and damaging the brittle carbon fibers.
Adhesive bonding means to join parts (adherents) via their surfaces with supplemental material (adhesive). To achieve structural and ageing resistant adhesive joints, formation of adhesion forces between adhesive and adherent in the boundary layer has to be reached.
This talk aims to give answers to the question, what kind of CFRP surface has to be created for high-strength and durable structural adhesive bonds. Furthermore, explanatory power of common surface analysis methods and the applicability of destructive test methods for CFRP adherents is discussed. For simplification, the assumption was made in this investigation, that high-strength adhesive bonding of CFRP means to bond to matrix resin and not to carbon fibers.
Polymer surfaces of different materials (thermoset and thermoplastic) were prepared with different mechanical and physical surface treatment methods to compare characteristics of the created surfaces and the achieved strength of the bonded joints. In addition, some samples were additionally treated to remove “low molecular weight oxidized material” (LMWOM) from the surface. Surface Analysis (SEM, XPS, REM, contact angle) was used to characterize initial and treated surfaces. Destructive tests (single lap shear, DCB, CATT) were used to determine the strength of adhesive joints. Additional ageing tests in hot and wet environment were used to investigate the ageing behavior.
Interestingly, the widespread opinion of surface functionalization as a dominating role for adhesion promotion on polymers was proved to be wrong for thermoplastics and thermosets. Even a high surface free energy is no requirement for high bonds strength on polymer surfaces. Molecular roughness seems to be the relevant surface property for high strength bonding of polymers.
Through the years Kaneka has developed several types of silane terminated polyethers.
A special and exclusive group within this polymer range are the acryl modified MS PolymerTM, a blend of silyl modified polyacrylates and silane terminated polyethers.
By combining polymers with a different chain composition and structure morphology can be controlled and hence the compatibility and Tg. It results in polymers with some unique properties as good adhesion to plastics, dissimilar materials and can be combined with high strength. An overview of the different acryl modified polymers will be shown together with their unique properties.
A specific case study of the adhering of luxury vinyl tiles will be presented and the formulation of a high strength plastics adhesive.
Light weighting is no longer optional. In the automotive and transportation industry, the goal for formulators and designers is to provide a lightweight design with the same or better safety features. To reduce weight, OEM’s currently use various material combinations using electro-galvanized steel, hot dipped galvanized steel, aluminum, carbon fiber, engineered plastics, etc. In the past, the metal was bonded with bolts, nuts and rivets to hold in place but currently, to improve the process and reduce process time, OEM’s are always looking for innovative products that can bond substrates well while decreasing process time.
CVC Thermoset Specialties has a range of reactive tougheners for optimum adhesive bonding with different substrates, accelerators for a fast cure at a lower temperature and specialty resins for reducing process temperature or time.
In this paper, CVC Thermoset Specialties has presented various data on the advantage of using HyPox® reactive tougheners for better T-peel strength and adhesion to oily substrates, OMICURE® urea accelerators for faster cure 1K adhesives and specialty epoxy resins for improving process conditions, reducing process temperature or process time.
New studies of amphiphilic block copolymer modifier for improved toughness of epoxy resins were carried out. The epoxy-functionalized block copolymers based on chain-extended polyesters were synthesized by attaching polyols having different structure and compatibility. Commonly used polyols are polyalkylene glocols as miscible and elastomeric polymers based on butadiene as immiscible copolymer. Generated carboxyl groups will be prepolymerized with an excess of epoxy resin to form epoxy groups between the polyol spacer. The amphiphilic multiblock copolymer was further used to prepare the microstructured epoxy thermosets. Influences of various polyol molecular weights, relations between miscible and immiscible copolymers and concentration of the chain-extender were studied, especially structure-property- relationships in term of solubility, resulting morphology as well as toughness characteristics.
Curable compositions containing about 5 to 20% by weight of the toughening agents relative to the epoxy resin will be described. The modifies epoxy resins were cured with a curing agent system consisting of dicyandiamide and urea. In order to achieve products having a high toughness, optimal ratios of the studies parameters are essential. Lower concentrations of chain-extender result in bimodal particle size distributions, high concentrations in unimodal distributions enabling investigations in adhesive formulations with different rubber particle size distributions.
Several industries have the willingness to reduce significantly their environmental footprint. To achieve this target, some actions can be carried out to decrease VOC emissions during the production step and/or emitted by goods during their life cycle; or to reduce energy consumption to manufacture goods.
Liquid polydiene resins, as liquid polybutadienes, are already incorporated in rubber compounds or adhesives compositions for their unique properties. Indeed, they are introduced in solid rubber-based compounds as process aids to reduce their viscosity or as coagent with some crosslinking agents to improve the crosslinking density of formulations.
In Adhesive & Sealant field, liquid functionalized polydienes can correspond to the base polymer of PU or Epoxy-based compositions, employed by Automotive or Coating Industries. To cure these compositions, some functional components, as diisocyanates or diamines, must be added in the latter. The formulations based only liquid polydienes are characterized by low VOC emissions and can be applied in temperature ranges from room temperature to 80°C (due to low viscosities in comparison with rubber compounds).
Sulfur-based systems and organic peroxides can be used to vulcanizate liquid non-functionalized and functionalized polydienes. Both vulcanization systems will be presented, as well as their main advantages. Some relations between the crosslinking systems and the final properties of liquid rubber-based compositions will be also reviewed to highlight their potential applications in Adhesive & Sealant Industry.
Abstract will be provided soon
The automotive industry faces significant changes. Powered by the developments in battery technologies and electronics, design and manufacturing of vehicles in the future will see fundamentally new opportunities and challenges, especially for AEV’s or HEV’s. The momentum towards e-mobility requires new material solutions in thermal management and adhesives for structural bonding, electrically conductive products as well as sealers for the next generation of battery systems. In the coming years the automotive industry will launch a multitude of alternative energy car models. The whole value chain will benefit from coordinated and complementary power units and production systems. Henkel supports these new concepts with product and system solution portfolios for the sealing of transmission housings made of multiple substrates, with potting compounds for fixing and protecting of electric motors and control units, with protective coatings and thermally conductive materials to manage heat, durable adhesives for magnet bonding as well as thermal interface adhesives for bonding battery modules to cooling systems.
The presentation will highlight specific examples with a focus on thermal interface materials.
Abstract will be provided soon
In many environments, undesired odours may be due to chemical degradation or transformation during production of such materials as well accumulated in the closed and small environments.
These substances can be various and they can generate a bad smell, a source of irritation or a health hazard. Since the human nose is very susceptible to odours / VOC (Volatile Organic Compounds) and tastes, only few ppm or ppb are sufficient to have the odour detected.
- are zeolites (pure Aluminium Silicate), highly active adsorbent, NON TOXIC, odourless, easy to handle, very fine, white and free flowing powder.
- represents an existing solution commonly used in markets like adhesives, building & constructions, coating, paintings, textiles as an additive to actively remove undesirable external odours and external VOCs (ACTIVE ADSORPTION).
- is as well a commercially-proven, existing solution commonly used as an additive to remove undesirable odours and volatile organic compounds (VOC) from the product itself (STATIC ADSORPTION).
The example shows successful case studies in building and construction materials and a theoretically calculation to design the dosage in order to obtain a desired lifetime of adsorption.
In the building industry, different construction materials and processes are well established worldwide. New combinations of different materials like timber-concrete-composites can bring benefits regarding lightweight design, increased prefabrication and faster building progress to increase productivity. By using timber-concrete-composite constructions, several advantages can be achieved in buildings such as weight reduction or an optimized load carrying capacity. Furthermore, the combination improves the reaction to fire as well as the deformation and noise reduction behavior.
A new approach regarding the usage of specific adhesive tapes between both, the prefabricated timber and the concrete part allows a fast curing by applying high temperatures in the bondline. The adhesive tape is based on an adhesively coated metallic carrier. The ends of the tapes are connected to an electric power supply similar to a welding workstation for controlled conductive resistive heating.
The adhesives have to fulfil a number of boundary conditions derived out of the different substrates (timber from beech and spruce, standard to high performing concrete with different surfaces) and should be able to cure at high heating rates by electrical heated thin metal carriers in the bondline. This is a very good precondition for a highly productive joining on the construction site. Additionally, the procedure is less sensitive to cold temperatures than the conventional method.
Investigations in the research project started with a screening for most appropriate adhesives in a broad range of polymer chemistry and were followed by a screening for the most suitable concrete surface. After defining the basic material an investigation for a scale up of the new method were carried out by producing specimens with a bondline of 170 cm length and 5 cm width.
Furthermore, the short and long-term behavior of bondlines produced with the fast heating adhesive-tape will be defined by two different test matrices via bending strength, block-shear and delamination tests. Therefore, specimens of dimensions up to 600 cm in length will be also produced and tested.
LANXESS Urethane Systems have developed unique prepolymers based on Low Free (LF) technology with less than 0.1% free methylene diphenyl diisocyanate (MDI) and other isocyanates for hot melt adhesives used in automotive, construction and electronics. This low monomer technology offers excellent performance, superior processing and productivity, as well as environmental, health and safety advantages.
This low monomer process enables design of prepolymers with a tailored balance between viscosity and NCO content for desired property and processing advantages as well as tailored reactivity. The broadly used approach in the hot melt reduced monomer prepolymers is to use different isomer ratio of 2,4 and 4,4 MDI as well as two prepolymers to tailor viscosity and reactivity. On the contrary, with our process we are targeting development of alternative approaches that do not require 2,4 MDI isomer and can be done with just one prepolymer. As an example, for hot melt adhesives Lanxess can synthesis LF MDI prepolymers with lower viscosity at the same NCO content compared to conventional MDI prepolymer route and allow for better wetting of tailored molecule and thus easier processing. This advantage offers a benefit for a number of hot melt adhesives applications including automotive, construction, woodworking, bookbinding, and electronics.
Low monomer urethane prepolymers minimize exposure to free isocyanate, a subject of increasing regulatory focus. Benefits of low monomer urethanes include unsurpassed industrial hygiene, enabling adhesive and sealant formulations to meet increasingly strict levels of free monomer, minimizing EH&S workload related to isocyanates, and eliminating any toxic classification (H351-free).The health and safety is especially important for industries where the hot melt adhesive are applied directly by construction and woodworking workers.
Lanxess low monomer technology is available across all isocyanate chemistries, including specialty isocyanates such as isophorone diisocyante (IPDI) and hexamethylene diisocyanate (HDI) offering exceptional clarity, as well as 1,4 phenylene diisocyanate (pPDI) offering outstanding solvent resistance and high temperature performance, and with a range of polyols, including polyethers, polyesters, polycaprolactones, and polycarbonates.
Crystallizing waterborne and solvent borne polyurethane adhesives are well known for providing tough and elastic bond lines with superior hot tear strength, making them the preferred adhesive technology for highly demanding and dynamically loaded adhesive applications in automotive, furniture and specifically footwear industry.
The reason for this exceptional performance is directly related to the combination of a high molecular weight polyester-polyurethane-backbone with a highly controlled crystallization kinetic specifically designed for each intended application.
However, applying this concept to hotmelt adhesive technology results in a high melt viscosity unfortunately combined with a limited thermal stability. Accordingly only low molecular weight derivatives have until yet found their way into commercial hotmelt applications.
We will report on a breakthrough in application and formulation technology for polyester-polyurethane-hotmelts that for the first time allows the processing and application of very high molecular weight polyester-polyurethanes via hotmelt technology, matching the performance of well-known waterborne and solvent borne heat activated polyester-polyurethane adhesives.
Adhesives based on renewable materials have recently been attracting attention due to the looming petroleum shortness and because of the new product design possibilities bio-based materials offer. Lignin, a byproduct recovered in large amounts from pulp and paper mills, is one of the most promising bio-based materials for adhesive applications due to its densely connected molecular structure rich in hydroxyl functional groups.
While lignin has already successfully been used to replace phenol in phenol-formaldehyde adhesives for particle boards 1 , plywood 2 and laminated veneer lumber 3, its application in formaldehyde free adhesives cured through non-condensation mechanisms remains underexplored. The reason for this lies on one hand in the difficulty of processing lignin, which is a non-melting solid with low solubility in common solvents, and on the other hand in its heterogeneity and multifunctionality, which make it difficult to produce a chemically exactly defined material from it.
In this work, chemical modifications of lignin with different renewable and non-renewable building blocks, such as succinic acid, 1,2-propanediol, fatty acids and polyethylene glycol were used to yield polymeric materials suitable for different non-condensation adhesive applications. Ligninpolymers with melting points up to 99 °C were obtained, while viscosities could be varied between 8 mPas (at 100 s-1, 25°C) and 18 000 mPas (at 100 s-1, 100 °C). The lignin derivatives were integrated in different types of adhesive formulations, including emulsion polymerisation isocyanates (EPI), 2-component polyurethanes (2K-PU) and polyurethane dispersions.
Both the dry and the wet shear strength of the thus obtained adhesives were tested and results will be presented. The evaluation showed that lignin derivatives have great potential to replace and complement petroleum based binders in adhesive portfolios.
1 N. S. Çetin, N.Özmen, International Journal of Adhesion and Adhesives 2002, 22, 481.
2 S. Kalami, M. Arefmanesh, E. Master, M. Nejad, J. Appl. Polym. Sci. 2017,134, 45124.
3 M. Fleckenstein, V. Biziks, C. Mai, H. Militz, fur. J. Wood Prod. 2017,419, 161.
Diols derived from Cashew Nutshell Liquid (CNSL) have unique characteristics compared to widely known polyester and polyether, and other natural based diols. Hydrophobicity is one key benefit provided by the long aliphatic side chain present in CNSL. This hydrophobicity reduces moisture sensitivity during cure with isocyanates and results in outstanding water resistance upon exposure to aqueous solutions, and ultimately contribute to increased durability of the final polyurethane systems. Different from other bio-based diols obtained from soy and castor oil, CNSL based diols also have an aromatic structure that contribute to excellent chemical and thermal resistance. The combination of aromaticity and long aliphatic chain from the diols delivers hydrolytic stability, improved compatibility with various diols, and balanced mechanical properties to polyurethane adhesives and sealants.
This paper will share test results including mechanical properties, chemical resistance, hydrolytic stability, and moisture sensitivity of CNSL-based diols compared to commonly used materials.