Showing papers by "Imperial Chemical Industries published in 2004"

Review of the toxicology, human exposure and safety assessment for bisphenol A diglycidylether (BADGE).

Abstract: BADGE (whose chemical names are bisphenol A diglycidylether and 2,2-bis(4-(2,3-epoxypropyl)phenyl)propane) is the lowest molecular weight oligomer in commercial epoxy resins and the major component in commercial liquid epoxy resins. The major application areas for epoxy resins are protective coatings and civil engineering. Additional applications include printed circuit boards, composites, adhesives and tooling, while a relatively small amount of epoxy resins (< 10%) finds use in protective coatings inside food and drink cans. The use of BADGE in food-contact applications was first regulated through EC Directive 2002/16/EC and amended in EC Directive 2004/13/EC with migration levels in food-contact applications being generally well below the regulatory thresholds. The paper discusses the commercial use of BADGE focusing on the current knowledge of human exposure from canned food applications. To assess the safety of this application, the exposure data are compared with no adverse effect levels (NOAEL) from various toxicological investigations with BADGE including reproductive and developmental assays, endocrine toxicity investigations, and sub-chronic and chronic assays. Consumer exposure to BADGE is almost exclusively from migration of BADGE from can coatings into food. Using a worst-case scenario that assumes BADGE migrates at the same level into all types of food, the estimated per capita daily intake for a 60-kg individual is approximately 0.16 microg kg(-1) body weight day(-1). A review of one- and two-generation reproduction studies and developmental investigations found no evidence of reproductive or endocrine toxicity, the upper ranges of dosing being determined by maternal toxicity. The lack of endocrine toxicity in the reproductive and developmental toxicological tests is supported by negative results from both in vivo and in vitro assays designed specifically to detect oestrogenic and androgenic properties of BADGE. An examination of data from sub-chronic and chronic toxicological studies support a NOAEL of 50 mg kg(-1) body weight day(-1) from the 90-day study, and a NOAEL of 15 mg kg(-1) body weight day(-1) (male rats) from the 2-year carcinogenicity study. Both NOAELS are considered appropriate for risk assessment. Comparing the estimated daily human intake of 0.16 microg kg(-1) body weight day(-1) with the NOAELS of 50 and 15 mg kg(-1) body weight day(-1) shows human exposure to BADGE from can coatings is between 250,000 and 100,000-fold lower than the NOAELs from the most sensitive toxicology tests. These large margins of safety together with lack of reproductive, developmental, endocrine and carcinogenic effects supports the continued use of BADGE for use in articles intended to come into contact with foodstuffs.

Synthesis, characterization, and emulsion polymerization of polymerizable coumarin derivatives

Abstract: We describe the synthesis of a new polymerizable coumarin derivative, [6-(β-acryloxyethoxy)-7-isopropoxy-4-methyl coumarin (3)], whose UV absorption spectrum significantly overlaps the emission spectrum of 9-alkyl phenanthrene chromophore. This dye can serve several purposes in latex films. It can be a tracer for fluorescence microscopy experiments, or it can act as a donor or acceptor dye in nonradiative energy transfer experiments. Here we emphasize its role as an energy transfer acceptor in experiments with phenanthrene as the corresponding donor. Coumarin-labeled poly(butyl methacrylate) latex dispersions could be synthesized by conventional batch emulsion polymerization with complete monomer conversion, complete dye incorporation, and uniform dye distribution. Attempts to extend this reaction to poly(vinyl acetate) copolymers failed because the dye inhibited monomer conversion.

Surfactant-driven motion and splitting of droplets on a substrate

Abstract: A theoretical and computational model is presented to predict the motion of a small sessile liquid droplet, lying on a solid substrate including surfactant effects. The model, as formulated, consists of coupled partial differential equations in space and time, and several auxilliary relationships. The validity of the long-wave, or ‘lubrication’ approximation is assumed. It is shown that there are circumstances where surfactant injection or production will cause the droplet to split into two daughter droplets. It is conjectured that the results are relevant to basic mechanisms involved in biological cell division (cytokinesis). It is also demonstrated that motion of a droplet, analogous to the motility of a cell, can be produced by surfactant addition. Computed examples are given here, in both two and three space dimensions. Approximate energy requirements are also calculated for these processes. These are found to be suitably small.

Method for ensuring that coating compositions have correct color

Abstract: A method suitable for use in small trade stores or retail shops for ensuring that coating compositions mixed in the store or shop have the correct colour in which colourants (II) are added to a base paint (2), the base paint (2) being provided in a lidded container (I). The base paint (2) is pre dispensed in a lidded container ( I ), thereby avoiding the need to weigh it accurately in store thus saving time. Further time is saved by adding the colourants simultaneously to the base paint (2). The actual load (usually the combined weight of the can and the contents) is compared to the correct load stored in a database and the operator is alerted if the two fail to match.

Rapid identification of cytochrome P450cam variants by in vivo screening of active site libraries

Abstract: The selection of cytochrome P450 enzymes from large variant libraries, and the subsequent use of these enzymes in preparative scale biotransformations, remains a formidable challenge due to the complexities of the associated electron transport systems. Here, a powerful approach for the generation and screening of P450cam libraries for new function is presented that is both flexible and robust. A targeted library was generated wherein only the P450cam active-site amino acids Y96 and F98 were fully randomized and biotransformations, using a novel P450cam whole-cell system, were screened by GC–MS for the hydroxylation of diphenylmethane. One in 50 of the reactions screened, including 16 different variants, produced 4-hydroxydiphenylmethane with up to 92% conversion observed in the case of the Y96A variant. These results demonstrate a primary example of the screening of P450cam libraries in a format that is compatible with extension to preparative scale reactions.

Rapid identification of cytochrome P450cam variants by in vivo screening of active site libraries

Abstract: The selection of cytochrome P450 enzymes from large variant libraries, and the subsequent use of these enzymes in preparative scale biotransformations, remains a formidable challenge due to the complexities of the associated electron transport systems. Here, a powerful approach for the generation and screening of P450cam libraries for new function is presented that is both flexible and robust. A targeted library was generated wherein only the P450cam active-site amino acids Y96 and F98 were fully randomized and biotransformations, using a novel P450cam whole-cell system, were screened by GC–MS for the hydroxylation of diphenylmethane. One in 50 of the reactions screened, including 16 different variants, produced 4-hydroxydiphenylmethane with up to 92% conversion observed in the case of the Y96A variant. These results demonstrate a primary example of the screening of P450cam libraries in a format that is compatible with extension to preparative scale reactions.

Compensating for human perception of colour

Abstract: A method, combination or apparatus for compensating for or predicting the shift in the human perception of colour which occurs when the colour is seen on a small surface area as compared with when it is seen extending over a large surface area. The compensation or prediction is performed by increasing (compensation) or decreasing (prediction) the lightness and chroma of the colour in a specified way. The invention allows choosers of colour to take account of the shifts when making their choice of colours and is useful in chosing colours for paints, plastics, textiles or illuminated surfaces.

Water-in-silicone oil emulsion for use as a sunscreen product

Abstract: A water-in-silicone oil emulsion contains (i) in the range from 0.1 to 25 % by weight of particles of metal oxide having a median particle volume diameter in dispersion in the range from 18 to 32 nm, (ii) 5 to 60 % by weight of silicone oil, and (iii) greater than 20 % by weight of water. The metal oxide particles are preferably incorporated into the emulsion in the form of an aqueous dispersion. The emulsion exhibits good skin feel, effective UV protection, stability and improved transparency.

Poly(vinyl acetate-co-dibutyl maleate) latex films in the presence of grafted and post-added poly(vinyl alcohol)

Abstract: We describe the synthesis and characterization of a series of poly(vinyl acetate-co-dibutyl maleate) [P(VAc-DBM)] latex particles (monomer molar ratio 10.6:1). One set of samples [high-M and M 250k SDS-P(VAc-DBM), gel content 50% and 0%] was prepared in the presence of an anionic surfactant sodium dodecyl sulfate. The other two sets of samples [high-M and M 250k PVOH-P(VAc-DBM)] were prepared in the presence of poly(vinyl alcohol) (PVOH). These polymers differ in gel content (50 and 0%) and the extent of PVOH grafting (30 and 15%). Polymer diffusion across cell boundaries in the latex films was monitored by fluorescence resonant energy transfer (ET) experiments. First, we examined M 250k samples in the presence of grafted and post-added PVOH. The presence of post-added PVOH (5%) causes a small but detectable retardation on the rate of polymer diffusion, whereas the presence of grafted PVOH (degree of grafting: 15%) significantly promotes the polymer diffusion rate. For the high-M P(VAc-DBM), the presence of post-added PVOH also retards the polymer diffusion. Strikingly, the presence of grafted PVOH (degree of grafting: 30%) in the high-M PVOH-P(VAc-DBM) promotes the polymer diffusion to such an extent that the diffusion was complete in the freshly prepared films. Our data also suggest that under our experimental conditions, the rate of P(VAc-DBM) diffusion increases with an increase of the degree of PVOH grafting. To confirm these results, we carried out fluorescence microscopy experiments to monitor the fate of PVOH in these latex films and found that in newly formed PVOH-P(VAc-DBM) films, the PVOH was either uniformly distributed in the P(VAc-DBM) matrix or the domains were too small to be resolved (i.e., < 0.5 μm).

Coating Composition Based on Modified Epoxy Resins

Abstract: A protective crosslinkable coating composition comprising modified epoxy resin and crosslinker the modified epoxy resin being the reaction product, by weight, of i) from 80 to 999 parts of di-epoxy resin of epoxy equivalent weight from 500 to 5000 and formed from the reaction of bis phenol A diglycidyl ether and bis phenol A and ii) from 01 to 20 parts of reactive material characterised in that a) the di-epoxy resin contains minor amounts of resin components of molecular weight less than 1000 Daltons, and the reactive material comprises b) mono-functional organic material of molecular weight at: least 100 Daltons having one moiety capable of reacting with the epoxy moieties of the di-epoxy resin and c) dicarboxylic acid of molecular weight less than 300 Daltons having two moieties capable of reacting with the epoxy moieties of the di-epoxy resin

Fire retardant coating composition

Abstract: A halogen-free fire retardant coating composition comprising film forming polymer, inorganic fire retardant material characterised in that the fire retardant material comprises a combination of fire retardant filler particles and a metal stannate and/or a metal hydroxy stannate wherein the overall PVC of the composition is from 75 to 97%.

A modified binder polymer for coating compositions

Abstract: A film-forming binder polymer for a coating composition such as a paint, varnish or woodstain where the polymer is modified by the presence of bonded moieties derived from plant gum, particularly plant fibre gum obtainable from plant fibre, especially corn fibre gum and more particularly moieties derived from proteo-xylans and/or furanose. The modified binder polymer minimises the need to use coalescing solvents without producing poor dried paint coatings which fail the scrub resistance tests also improves the opacity of the dried coating composition.

Autoxidisable architectural coating compositions

Abstract: An autoxidisable architectural coating composition suitable for application to surfaces found in and around buildings at ambient temperatures and in natural daylight by unsophisticated users having no respiratory protection wherein surface autoxidation of the composition is promoted by a combination of low concentrations of metal ions (especially manganese or vanadium) and at least one photoinitiator. The composition avoids the need to use more than trace amounts cobalt ions which are rumoured to be carcinogenic yet achieves adequately fast rates of autoxidation. Preferably the use of cobalt is avoided altogether. The use of the low concentrations of the other metal ions reduces discolouration of the compositions often to levels below what is achieved using conventional cobalt promoters. It also improves gloss. Also a modification in which surface autoxidation is promoted by a combination of a photoinitiator and trace amounts of cobalt ions in the absence of other surface autoxidation promoting metal ions. Finally, a method for applying the autoxidisable coatings to surfaces under ambient temperatures in which they are subjected to natural daylight or similar low energy irradiation.

Column stabiliser for stacked cans

Abstract: A column stabilising grid ( 1 ) is described for use in constructing stable columns of stacked objects, such as containers of paint. The grid ( 1 ) has a perimeter wall ( 2 ) bounding a number of locating cells ( 3 ) defined by walls ( 6 ) and ( 7 ) extending from a floor ( 4 ). Primary locating walls ( 6 ) are dimensioned to receive the base of a larger object and to resist lateral movement thereof. Secondary locating walls ( 7 ), each encompassed by a primary locating wall ( 6 ), are dimensioned to receive the base of a second, smaller object and to resist lateral movement thereof. The secondary locating walls ( 7 ) are eccentrically located within the primary locating walls ( 6 ). Stop means ( 10 ) and ( 11 ) depend from the underside of the grid ( 1 ). In use, a column is constructed by placing a grid ( 1 ) between adjacent layers of objects in a stack. The locating means of a first grid receive the bases of containers in one layer whilst the stop means on the underside of a second grid ( 1 ) abut against the tops of the containers in the layer. In this way, a stable compound column having a number of individual stacked objects can be constructed.

Large can for a brushable coating composition

Abstract: A large can (1) suitable for containing a brushable coating composition of the type applied at ambient temperatures to surfaces of buildings and which can is conveniently closeable by a screw-thread lid (7) where the opening (2) into the can is provided with screw-threads (5) formed around its external surface and a brushwipe (9) preferably comprising an edge (10) having different curvatures (10 a and 10 b) located in a position remote from the screw-threads Provision of the brushwipe guards against the wiping of an overloaded paint brush on areas of the opening from which paint wiped from the brush could run to block screw threads and so make use of the screw-thread lid impracticable The can preferably also contains a re-entrant rebate (32) in its side wall (37) to provide a brush rest (34) within the can and also means for guiding a user of the can to hold it in a preferred orientation during painting