The development of a new stabilisation concept for improvement of the heat and light resistance of coatings for interior and exterior automotive applications is described. The use of UV absorbers and hindered amine light stabilisers(HALSs) to protect coatings against sunlight is discussed. Experimental xenon weather-O-meter studies were conducted of the use of a 1:1 combination of a benzotriazole UV absorber and a HALS in solvent-borne and water-borne PU coatings on plaques of polycarbonate/polybutylene terephthalate blends. Accelerated weathering exposure and heat exposure on interior car part systems were also studied, the HALSs used acting as both radical scavengers and heat stabilisers. Additional solutions for convertible cars were examined. (ECS, Nuremberg, Germany)

The development of new raw materials for one-component crosslinking adhesives and sealants is described, with reference to the reduction of organic solvent content in the products, to preparation of water-borne systems with reactivity at least equal to that of solvent-borne systems and to the need for straight-forward processing without the need for detailed preparation. Particular attention is paid to latently reactive isocyanate crosslinkers for PU, i.e. surface-deactivated solid isocyanates dispersed in a finely-divided form, nanoparticle silica sols for use in polychloroprene dispersions, and developments in silane-terminated PU prepolymers.

Henkel's process for reducing the isocyanate emissions of moisture-curing PU hot-melt adhesives to a harmless level, thus making the adhesives exempt from hazardous substance labelling, is described. The problems encountered during the development of the technology are discussed and development 'dead-ends' are outlined. The use of Super MDI (the demonomerised MDI adduct) and of asymmetrical 2,4'-MDI is considered and it is shown that these technologies can be highly complementary. 8 refs.

The determination of specific emission rates for PU hot-melt adhesives in order to assess the risks associated with isocyanate-based adhesives is described. The method is carried out in special laboratory cells in which the emitted isocyanate becomes chemically bound to glass fibre filters doped with 1-(2-pyridyl)piperazine. Subsequent quantification of the bound substances is carried out using liquid chromatography with UV and fluorescence detection. Experimental data are presented and the development of a model for estimating the effects on real workplace concentrations is discussed. 2 refs.

Photoinitiated crosslinking polymerisation was used to prepare polyurethane acrylate, polyphenoxy acrylate, polyester acrylate and cycloaliphatic epoxide clay-based nanocomposites. The solvent-free resin containing 3 wt% of organophilic clay was cured within seconds on UV irradiation at ambient temperature. IR spectroscopy studies showed that the polymerisation reaction was rapid in thick samples (2 mm) because of the higher exotherm and the resulting rise in temperature. The organoclay did not slow down the photopolymerisation of either acrylate or epoxy resins. The presence of clay nanoparticles reduced the gloss of UV-cured coatings because of enhanced surface roughness. The viscoelastic and tensile properties of the nanocomposites were comparable to those of the neat UV-cured polymer but their moisture resistance was significantly increased. 35 refs.

In order to evaluate the durability and longevity of composite organic coating systems, the weathering-induced ageing must be characterised as a function of its nature and spatial distribution. These coatings are opaque and have heterogeneous compositions, so depth profiling is difficult using established techniques. The feasibility of using femtosecond time-scale laser pulses as a method of preparing coating samples for depth-resolved spectroscopic analysis was investigated. The military coating studied was a chemical agent resistant coating consisting essentially of a low gloss, highly crosslinked poly(ester-urethane) structure loaded with nanoscale titanium dioxide which gave a grey colour for optical camouflage. Larger silicaceous extenders were added to the coating to lower the gloss levels. Ablated square regions of various depths were made in the coating samples and their morphologies were characterised using a custom scanning confocal profilometer, FTIR spectroscopy, SEM/energy dispersive spectroscopy and dispersive Raman spectroscopy. Depth profiles from the ablated samples were compared with profiles of the same material made using a cross-sectional transmission mode FTIR technique. A threshold was found, below which a compound-selective ablation process was observed. Additional ether crosslinking occurred at moderate/high energy levels. Material in the residual interaction volume showed indications of reconstitute urethane functionality. It was concluded that depth profiling by ablating multilevel windows in a coating system to enable spectroscopic analysis of the underlying regions to be carried out was not currently possible. 45 refs.

A report is presented on the use of PVDF-acrylic interpenetrating polymer networks (IPN)s for the manufacture of solvent and water-borne coatings with excellent exterior weatherability. Pigment selection and IPN generation in water-borne systems are discussed and the mechanisms responsible for the excellent weatherability are indicated. The performance of the IPN coatings is compared with that of acrylic and urethane resin coatings in colour change tests and IPN morphologies with 70% PVDF are shown to perform particularly well in weathering, colour retention and chalk resistance tests. 10 refs. (8th Nuernberg Congress, Creative Advances in Coatings Technology, Nuremberg, Germany, 25-26 April 2005)

The design of low molec.wt. acrylic and polyester polyols for use in VOC compliant, high performance high solids PU coatings and a polyester diluent, which maximises VOC reduction when combined with a high Tg acrylic polyol, is reported. The characteristics and performance properties of the polyols and properties of automotive clearcoats based on blends of the diluent and acrylic polyol are presented and discussed. 5 refs. (8th Nuernberg Congress, Creative Advances in Coatings Technology, Nuremberg, Germany, 25-26 April 2005)

The development of a simple sandwich plate theory for a sandwich plate simply supported along two opposite edges, free along the two other opposite edges and loaded by a line load using a superposition approach is described. The theory is applied to a low-cost sandwich plate with glass/PETP facesheets and a polyamide/PETP core bonded with a PU adhesive and the predictions compared with out-of-plane displacements from dial gauge and shadow Moire measurements.

A look is taken at the market for medical plastics, recent developments in polymers and packaging films for the medical industry and some award-winning designs of medical devices. Some of the polymers and devices mentioned include PEEK for implants and coatings, medical-grade PU elastomers, thermoplastic elastomers, thermoformed PU medical balloons, antibacterial polymers, engineering plastics, a portable, automated blood collection system and an electrocardiogram monitoring system. A list of contacts is included

The surface treatment of styrene-butadiene-styrene (SBS) rubber soles by various aqueous inorganic and organic chlorinating agents, such as acidified sodium hypochlorite solution or aqueous trichloroisocyanuric acid (TCI) solution was investigated by ATR-FTIR, XPS, contact angle measurements and SEM. The adhesion properties of treated SBS rubber/waterborne polyurethane adhesive/roughened leather joints were studied by T-peel strength tests, and the results are discussed in comparison with those for SBS rubber treated with TCI in organic solvents. 17 refs.

The surface treatment of sulphur-vulcanised styrene-butadiene rubber formulations to remove paraffin wax by ultrasonic cleaning with methyl ethyl ketone prior to plasma torch treatment was investigated. The surface modifications were analysed using contact angle measurements, ATR-FTIR, XPS and SEM, and the adhesion properties of treated rubber/polyurethane adhesive joints were evaluated by T-peel strength tests. 23 refs.

The effects of heat sealing conditions on the strength of heat sealed laminated films of biaxially oriented nylon and cast linear low-density polyethylene films with a urethane adhesive were investigated by FTIR, DSC, peel strength test and tensile properties. The results are discussed in terms of the relationship between crystallinity and mechanical properties of the heat-sealed part. 19 refs.

Considerable research, in progress in university, government and private laboratories, promises not only a better understanding of existing nanomaterials, but new materials as well, together with more efficient, cost-effective processing techniques and methods for using their unique properties in practical applications. Tier 1 nanocomposites can be viewed as an evolution of filled polymer technology. In this category, nanoclays are expanding into aerospace applications. Upcoming applications include sacrificial ablative materials for rocket motor casings. Recent work by the Air Force Research Laboratory and others has involved using carbon nanotubes in shape memory polymers to make actuators. Three years ago, Metal Matrix Composites began to make and explore Tier 2 opportunities for metal nanofilaments. Currently, the company is exploring the use of nickel nanofilaments to create conductive paths in polymers such as adhesives, coatings and elastomers. Lightning-strike materials probably will be one of the earliest applications that will emerge. Tier 3 nanocomposites are still very much in the basic research realm right now. These could be defined as "true" nanocomposites, designed and built with precise control of the nanoscale distribution and orientation of the nanoparticles in the matrix.

Composite parts are decorated for a number of reasons. In most cases, the appearance of the part as it exits the mould lacks the desired surface smoothness, colour, texture and/or other desirable characteristics. While a post-mould coating can add value, improve aesthetics and extend the life of the part, it historically has added significant cost and an additional production step. Until recently, coating the part in the mould had significant limitations. In the past few years, however, several new options have emerged as practical alternatives to post-mould coating of composites, including for the first time, the possibility of giving a Class A surface to long fibre-reinforced thermoplastic materials. Other techniques include the co-moulding of thermoformed multilayer thermoplastic "skins", the application of paint to the mould surface prior to moulding and the application of a coating to a cured composite part while it is still in the mould.

A two-component PU clearcoat has passed washing and weathering tests with flying colours at the Coatings Testing Laboratory at Bayer MaterialScience. The 2K-PUR clearcoat is a special blend of the proven PU coating raw materials Desmodur and Desmophen. When a coating formulated with these two raw materials is heated slightly, small blemishes flow back together and all this "self-healing" process needs is a little sunshine. Not only must it be scratch resistant, this thin layer also has to repel a variety of aggressive substances to which the surface is exposed over the course of the year, including road salt, tree sap and bird droppings. A resistant coating also has to be able to withstand temperatures between -30 and 70C, as well as UV radiation and high humidity.

In the manufacture of nonwoven products, the adhesive (or binder) plays a critical role in determining the final fabric properties. This article focuses on the use of paste dot for the bonding of nonwovens to themselves and other substrates. The paste-dot adhesive dispersion can be formulated to meet a variety of applications, substrates or property requirements. The base polymer is generally a low-VOC polymer such as a copolyamide or copolyester. The formulation can usually be done with a range of additives, such as plasticisers, thickeners and dispersing agents. The paste dot bonding process is described. 4 refs.

By conducting tests on a selection of novel or difficult-to-adhere substrates, it is possible to make inferences that may help narrow the choice of adhesives. Low-surface-energy materials such as plastics do not allow adhesives to wet out, making them generally poor candidates for bonding. Tests were carried out on a range of substrates, including acrylic, aluminium, polycarbonate, nylon, polysulphone, stainless steel, titanium, polyetherimide, polyimide and PU. To promote adhesion to novel substrates, SP-270, a unique primer containing a proprietary blend of silanes, catalysts and solvents, was developed. R31-2186, a fast-cure addition-cure adhesive, was used in conjunction with this primer. ASTM D 1002 was the test method reference. The substrates were flame-treated and then primed with SP-270 silicone primer. This adhesive/primer system had 100% cohesive failure with all the substrates.

A new waterborne self-crosslinking acrylic polymer has been developed to improve the performance of these systems in automotive interior plastics. The polymer exhibits outstanding adhesion to a variety of rigid plastic substrates and demonstrates excellent chemical resistance. It also provides the flexibility and wear resistance required for interior automotive plastics coatings. The chemical resistance is equivalent to that of crosslinked systems, and the polymer shows improved adhesion and metallic pigment compatibility.

Automotive components being prepared using in-mould processes include instrument panels, door panels, steering wheels and airbag covers. The in-mould processes used are PU sprayable elastomer, injected PU elastomer and PU foam. Most of these applications utilise waterborne in-mould coatings. The technology provides solutions to many of the shortcomings associated with post-paint systems while delivering a part with equal to, and in most cases, superior coating performance. A step-by-step process description for producing a finished part by the in-mould process is given. Test results are presented comparing two different types of in-mould coatings to their corresponding post-paint coatings.

While much prior art deals with various methods of producing aqueous PU resins and PU dispersions, no publications appear to disclose an effective method of preparing water-dispersible non-uniform and nanostructured, in particular core-shell, PUs. A new methodology for making nanostructured and non-uniform PU dispersions having a wide range of morphologies has been developed. The method is comprised of the preparation of two prepolymers with different hydrophilicities. The key distinguishing feature of the process is that the two prepolymers are intimately pre-mixed before the dispersion step. Surprisingly, the mixture "remembers" that it was made of the two different prepolymers and, in the presence of water, diffusion of hydrophilic components to the water/particle interface and of hydrophobic components to the interior of the particle begins. The interplay of diffusion, phase separation and chain extension determines the morphological outcome. Various previously inaccessible PU particle morphologies, including core-shell and "ice-cream cone" have been prepared. 13 refs.

The use of automotive adhesives is becoming a popular collision-repair method for metal bonding, plastic bonding, metal-to-plastic bonding, plastic repair, seam sealing and foam application. By gaining an understanding of each option and its intended use, selecting the right adhesive can be easy and efficient. Acrylics, urethanes and epoxies are the most widely used collision-repair adhesives, and all have unique attributes.

Vinyl acetate- and toluene-borne two-component PU adhesives are still the main varieties used in the flexible packaging market in China. However, reports of solvent residue problems in packaging and cost pressures from upstream products such as crude oil, are pushing the flexible packaging adhesive market towards more environmentally friendly and healthy products. Water-borne flexible adhesive producer Rohm & Haas sponsored two flexible packaging seminars in China in 2002 and 2004 to promote "green" adhesive and ink. The company is now the largest water-borne flexible adhesive player in China. Henkel is also promoting its solvent-free adhesive in China, but the development is very slow compared with water-based adhesive as it needs new investment in lamination machines.