Showing papers by "Imperial Chemical Industries published in 2006"

Thermal stability of reversible addition–fragmentation chain transfer/macromolecular architecture design by interchange of xanthates chain‐transfer agents

Abstract: A series of chain-transfer agents used in reversible addition–fragmentation chain transfer/macromolecular architecture design by interchange of xanthates polymerizations were subjected to thermogravimetric analysis and gas chromatography/mass spectrometry to assess their stability to heat and to determine their degradation pathways. The effects of the chain-transfer-agent class and structure on the thermal stability are described. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6980–6987, 2006

Experimental chemotherapy of infection with agents of the psittacosis‐lymphogranuloma‐trachoma group

Abstract: I t is the third compound observed by us to possess reasonable activity against the largest viruses without having appreciable antibacterial action. For reasons which will be evident later, we deemed it desirable to assess its activity relative to that of other substances in common therapeutic use. Given as a single dose 2% hours after infection into the yolk sac of the developing chick embryo, Nitractin approximates closely to chlortetracycline or chloramphenicol in activity against the virus of psittacosis (strain MOH 154). I t is about a tenth as active as the other tetracyclines, erythromycin, or oleandomycin. Most strains of psittacosis virus are more resistant to penicillin and to carbomycin and highly resistant to the sulfonamides. I.C.I. 17,025 is equally active against all strains tested of the following viruses: lymphogranuloma (JH, Ross) ; trachoma (T'ang, G1, G17) ; inclusion blennorrhea (Dav. LBl). These viruses, however, are relatively more susceptible to the tetracyclines, erythromycin, oleandomycin, penicillin, and the sulfonamides. The minimally effective doses of the various substances for these infections in the chick embryo appear in TABLE 1. It is more difficult to obtain comparable figures for the various infections in the mouse. We have succeeded in adapting the two strains of lymphogranuloma and one each of trachoma (T'ang) and inclusion blennorrhea (LB1) to the mouse, but only by the intracerebral route: which militates against successful therapy with a number of agents. Moreover, the infections so produced tend to be mild; few of the infected animals die and, after a period o€ characteristic symptoms, the majority recover. The assessment of therapeutic effect is, therefore, the undesirably subjective one of deciding what dose of an antibiotic or synthetic chemical will wholly abolish symptoms in the infected animal. TABLE 2 presents the minimally effective doses judged by this criterion. With psittacosis, an intraperitoneal infection is contrasted with an intracerebral one to indicate the degree to which therapy suffers with the latter route of inoculation; since the doses are those necessary to abolish symptoms at a time when

The evaluation of several topical corticosteroid preparations in the blanching test

Abstract: Summary.— Several commercially available topical corticosteroid products have been evaluated in the blanching test. Fluocinolone acetonide preparations are extremely effective, and the ointment is superior to the other ointment products. Fluocinolone acetonide cream and gel produce a more prolonged effect than other cream products.

Emulsifiers and emulsions

Abstract: An emulsifier which is a protein/polysaccharide conjugate derived from whey protein and a non-ionic polysaccharide, more particularly dextran, maltodextrin or gum Arabic, is described together with its application in emulsions and beverages.

Placebo Ointment Response in the Blanching Test

Abstract: REFEREN'CES CREAM, J . J. (1971) Iniiiuinoiluorescent Studios of tho Skin in Cryoglobiilinaemic Va-sciilitis. Br, J. Derm., S4, 48. HEITMANN, H . J . & KxuKEN, N. (1970) Iinniunofluorescenzserologische Untersuchiingen bei dcr Vasculitis Ruiter. Arch. klin. e-xp. Derm.,237, 59, LtJDERS, G. (1970) Zur Pathogoncso drogeiiallcrgischer Morphen an Her Haiit. Arrh. H'ii>. foiji. Derm., 237, 201. MiESCHER, P. A., PAKONETTO, F . & KoFFLER, I). (1965) Immunofluorescont Studies in Human Vasculitis. In Immunopaihology. IVlh Intel-national Sn-inposiwn. Ed. P. Grabar and P. A. Micscher. Basel: Schwabe. P. 446. BuiTER, M. (1965) Vornehmlich auf die Haut beschrankte altergische Vaskulitiden. Zentbl. Pklebologie, 4, 120.

Method of producing a coating composition

Abstract: A method of producing a coating composition in an in-store tinting machine comprising the steps of selecting a base paint, adding at least one additive to the base paint, adding at least one colorant to the base paint, the at least one colorant being selected from a range of colorants in the in-store tinting machine, mixing the base paint, the at least one colorant, and the at least one additive so as to produce a coating composition, in which the additive is not a base paint or a colorant from the range of colorants in the in-store tinting machine.

Anti-Microbial Paint Films

Abstract: An anti-microbial, solid architectural paint film produced by applying a liquid paint composition to a work surface, wall, ceiling or floor and allowing it to dry wherein the paint film comprises i) a film forming polymer and ii) an anti-microbial substance, comprising a metal or metal compound deposited on a particulate inorganic material, in an effective amount to kill microbes or prevent their growth on the surface of the solid coating and wherein the paint film is free of metallic copper and zinc and their alloys.

Evaluation of the fragrance characteristics of a substance

Abstract: Apparatus for evaluating the fragrance characteristics of a substance comprises a cylindrical chamber (2) in which is located a block (3) for supporting a substance, e.g. a fragrance to be evaluated. A flow of air, generated by a fan (4), passes through the chamber (2), around the substance and leaves the chamber via a main outlet (7) and a plurality of sensing outlets (12) each provided with a metering valve (13) leading the air flow to a corresponding nasal mask (16). Individuals take two or three sniffs of the air flow from the mask and record their findings on a pre- prepared form.

Population Balance Model for Emulsion Polymerisation Under Pseudo-Bulk Conditions: Combined Particle Size Distribution and Molecular Weight Distribution

Abstract: A comprehensive model for emulsion polymerisation is presented, accounting for particle size distribution (PSD) and molecular weight distribution (MWD). The PSD information is incorporated through a population balance framework. A mechanistic formulation is adopted in modelling the average number of radicals/particle under pseudo-bulk compartmentalisation conditions. The method of moments is adopted to simplify the MWD equations over each discrete size class. The impact of the pseudo-bulk assumption on the PSD and MWD results is assessed. An identification of potential manipulated variables for control of PSD and MWD is done through sensitivity analysis.

Dilution of topical corticosteroid formulations

Abstract: SIR, The dilution of commercially available corticosteroid formulations is common practice in the U.K., although unknown in some other countries. We believe that ad hoc dilutions are, in principle, undesirable and that, if their use is considered to be essential, the choice of diluent should be based on rational considerations. Many of the 'compound' mixtures of corticosteroids with coal tar, cade oil and the like may lack both pharmaceutical stability and therapeutic justification. The clinical efficacy of dilutions of commercial steroid formulations depends entirely on the degree of dilution, and a preparation such as Synandone, containing half the fiuocinolone acetonide content of Synalar, is superior to i\" „ hydrocortisone. On the other hand, it is extremely unlikely that a dilution containing as little as 10\" „ of the original formulation offers any advantage over i\" „ hydrocortisone. The powerful topical anti-inflammatory steroids, such as fluocinolone acetonide or fluocinonide, are complex molecules and are present in very small amounts (Synalar ointment contains 250 p.p.m. of fluocinolone acetonide). The risk of total chemical decomposition is greater than with high strength active agents. Pharmaceutical companies spend much research effort in selecting optimum formulations, taking into consideration chemical and physical stability, together with clinical efficacy. Any alteration or addition to such a formulation can radically alter any or all of these factors. For instance, in alkaline vehicles such as Boots E45 Cream, Synalar (fluocinolone acetonide) and Metosyn (fluocinonide) undergo oxidative degradation at the 11 and 21 positions. Thus, a dilution of 20\",, Metosyn in E45 cream loses 50\",', of its steroid concentration after i month's storage at 23 C. The selection of an effective preservative for a topical cream is of crucial importance. Many of the preservatives commonly used in pharmaceutical emulsions are adsorbed or bound by non-ionic emulsifiers (these are usually used in corticosteroid creams) and this bound preservative is devoid of antimicrobial activity. An additional factor is the oil/ water solubility (partition coefficient) of the preservative. The degree of preservation depends on the availability of the preservative in the aqueous phase. If, on dilution of a well preserved cream, further oils are added, the preservative may tend to partition into that oil phase leaving the product in a badly preserved state.

Photogrammetry applied to pipe systems of chemical plant

Abstract: A successful attempt has been made to produce design plans of large chemical plant using photogrammetric techniques, and involving the development and modification of cameras and plotting equipment. Photogrammetry has provided a solution to a problem which could not easily be solved by direct methods. Resume Dans le but de preparer les plans de construction des usines de produits chimiques ľauteur a developpe une methode photogrammetrique qui apporte certaines modifications aux appareils de prise de vues et aux restituteurs. La photogrammetrie a donne une solution economique a un probleme difficile a resoudre par des moyens directs.

Improved coating composition.

Abstract: A pigmented, aqueous coating composition comprising i) an aqueous dispersion of non-crosslinkable addition oligomer of weight average molecular weight of from 5000 to 15000 Daltons and calculated Fox Tg greater than 0°C and less than 50°C ii) an aqueous dispersion of addition polymer of weight average molecular weight greater than 53,000 Daltons, calculated Fox Tg greater than 10°C and less than 40°C and mean particle diameter of less than 150 nanometers, where the ratio of i):ii) is from 0.25:1 to 2.70:1, based on % weight dispersion solids.

Multi-period capacitated lot sizing with variable batch sizes

Abstract: In the production planning for strong seasonal demand products, it is uneconomical to configure the supply chain for throughputs equivalent to the demand peaks. Instead, a holistic approach to supply chain optimisation is adopted where forward demand forecasts drive the production planning process. There is a considerable amount of research literature available for the various types of lot-sizing models involved in production planning. It is generally assumed in these models that a continuous production system is employed for the relatively high volume, low value products. However, these models are not directly applicable for a large number of specialised products operating in batch mode for increased flexibility on multi-purpose equipments. This research addresses the batch sizing operation within a lot-sizing model in order to derive a simultaneous batch sizing and production planning optimisation. The degrees of freedom in this combined problem are the monthly batchsizes of each product, integer number of batches of each product produced each month, amount of overtime working and outsourcing required in each month as well as the time-varying inventory positions across the chain are manipulated. Values for these are selected to balance the trade-offs in batch costs (each batch produced incurs a fixed charge associated with set-up and cleaning), stock costs (these are proportional to the product batchsizes and the amounts of inventory carried) as well as the overtime and outsourcing costs. In greater detail, the multi-item lot-sizing problem has been extended to incorporate the batch-sizing complexity, where the production costs are aggregated to the batch level, with an additional discrete dispersion cost proportional to the batchsize. The operational requirements for overtime work and outsourcing are presented as vector constraints of each product. Through linearisation of the inherent non-linear product of the integer number of batches and its corresponding batchsize, a mixed-integer linear programming (MILP) model is formulated with a minimum cost objective function. For a large number of products with consumer paints, this single-stage deterministic model is intractable due to the large number of variables involved, despite effective reformulations for tighter linear programming relaxations. Methods have been developed in the research to disaggregate the vector constraints from the batch sizing and production planning model for each product. These implicitly or explicitly utilise decomposition algorithms to reduce computational complexity and solution times. They are able to solve the applied industrial problem.

Low voc coating composition

Abstract: A pigmented, aqueous coating composition comprising i) an aqueous dispersion of non-crosslinkable addition oligomer of weight average molecular weight of from 5000 to 15000 Daltons and calculated Fox Tg greater than 0° C. and less than 50° C. ii) an aqueous dispersion of addition polymer of weight average molecular weight greater than 53,000 Daltons, calculated Fox Tg greater than 10° C. and less than 40° C. and mean particle diameter of less than 150 nanometers, where the ratio of i):ii) is from 0.25:1 to 2.70:1, based on % weight dispersion solids.

particulate dry tinter

Abstract: A particulate dry tinter for use in tinting a coating composition including at least two coloured pigments, in which the particulate tinter has a colour hue predictive of the colour hue of the tinted coating composition and the coating when applied (FIG. 1 ).

Rheology in Coatings, Principles and Methods

Abstract: Rheology by definition is the study of the deformation and flow behavior of materials. An operational definition would be “the study of the response of certain materials to the stresses imposed on them”. Rheology seeks to understand the relationship between applied force, or stress, and the resulting deformation, particularly for materials showing nonsimple responses. Such a relationship expressed mathematically is termed a constitutive equation. Perhaps the most familiar such equation is Hooke's law for elastic solids, which states the linear relationship between the stress σ and the deformation or strain γ [Equation 1]: (1) where the modulus G is the constant of proportionality. However, rheology is primarily concerned not with the solid state but with the study of fluid behavior, and the simplest constitutive relation for a liquid is Newton's law [Equation 2]: (2) where the coefficient of viscosity or, more commonly, the viscosity η expresses the proportionality between stress and, now, not strain but the strain rate, . For the ideal, simple materials described above, G and η are called material constants because they are dependent only on the thermodynamic variables of temperature, pressure, and concentration, similar to a material property such as the density. However, rheology is not concerned with either Hookean solids or Newtonian liquids. It is rather concerned with materials whose constitutive relationships involve complex behavior. For such materials, G and η are no longer material constants but material functions. Their values will now depend on variables such as the magnitude of applied stress, strain, strain rate, and even the deformation history. In fact, for rheologically interesting materials, the behavior is somewhere between that of a Newtonian liquid and an elastic solid. Such materials are termed non-Newtonian, and may display time-dependent, plastic and viscoelastic behaviors. Paints and industrial coatings, creams and lotions, inks, adhesives, ceramic slips, solder pastes, foods, medicines, etc. are representative of the range of materials whose commercial viability depends on having the correct rheology for the application. In turn, the required rheological properties must be defined with reference to the specific process at hand. This article introduces the science of rheology, with description of basic terms, models, and methods used. The mechanisms responsible for complex rheological behavior and the use of rheological measurements to understand and control the flow of materials are described. The emphasis is on coatings and coatings processes as points of reference, but the principles discussed apply to a wide range of materials and industrial products.

A method of producing a coating composition in an in-store tinting machine

Abstract: A method of producing a coating composition in an in-store tinting machine comprising the steps of selecting a base paint, adding at least one additive to the base paint, adding at least one colourant to the base paint, the at least one colourant being selected from a range of colourants in the in-store tinting machine, mixing the base paint, the at least one colourant, and the at least one additive so as to produce a coating composition, in which the additive is not a base paint or a colourant from the range of colourants in the in-store tinting machine.

A simple comparator for measuring from photographs

Abstract: Some applications of photogrammetric techniques do not require the high standard of accuracy in instrumentation which we have come to associate with air survey. The comparator now described provides a simple solution to a particular problem. It requires neither a skilled operator nor stereoscopic vision, and could be used by the average office draughtsman.

A coating composition

Abstract: A coating composition comprising a first part, and a second part, in which the first part includes gypsum and/or cement dispersed in a water miscible organic solvent, and the second part includes a water soluble polymer, the first and second parts being mixable so as to form a hardened coating composition.

Surface Energetics of Polymers and Rubbers, Characterization of

Abstract: Adhesion of polymeric materials to various substrates, from metals to glass to other polymers, is a subject that continues to grow in importance, with today's technologies. The biocompatibility of polymer-based implantable devices and prostheses is largely determined by the tendency of the material surfaces to be ‘wetted’ or adhered to by proteins. Surface and interfacial energy relationships determine in large part whether the adhesive and adherend achieve the intimacy of molecular contact that is a requisite for good adhesion. An aspect of the behavior of polymer blends and of block copolymers is that, depending on the relative surface energy of the components, and on the phase morphology and chain mobility, lower energy components may segregate to the surface to the detriment of interfacial adhesion, or perhaps promoting heterophase nucleation. There are numerous both technological and scientific motivations for the characterization of polymer surface energy. The objective in surface energy measurement is to characterize the free energy of a solid or a liquid surface (or, in general, an interface). The surface free energy per unit area (or surface tension) of polymers is a fundamental property. It may be measured in the solid, liquid, or solution state, but perhaps most often the intention is to refer the measured value to the solid state. Hence, one approach involves measuring the surface tension of polymer melts and low molecular weight liquid polymers by conventional methods and using one of several equations to extrapolate to values for the polymer in the solid state. Methods for determining the surface energy of solid polymers usually involve measuring the contact angle of a sessile liquid drop, and this methodology will be discussed in some detail. A relatively new technique for direct polymer surface energy measurement based on Johnson, Kendall, Roberts (JKR) (contact mechanics) theory will be discussed.

Thermal Analysis of Coatings

Abstract: The thermal analysis of coatings involves measuring the response of a material when subjected to a thermal stimulus, sometimes in combination with a mechanical stress. The thermal stimuli used in the thermal analysis of coatings include linear temperature ramps, a sinusoidal modulation around a fixed temperature, the superposition of a linear ramp and a sinusoidal modulation, and a simple isotherm in which some property of the material is monitored as a function of time. The responses measured by the thermal analyst include: melting, crystallization, evaporation, degradation, stress relaxation, softening point, and glass transition, as well as physical properties such as the elastic and viscous moduli. These responses aid in the development, characterization, and determination of the proper application and bake conditions for a wide range of coatings. In general, thermal analysis techniques are very sensitive and, for many applications, a sample mass of the order of 10 mg is sufficient. However, the assignment of a thermal event to a particular chemistry or morphology requires knowledge of the system being analyzed or another analytical technique. For example, thermal analysis can accurately determine the temperature and enthalpy of a crystalline polymer melt but it does not provide any other information as to the chemistry of the polymer. Assigning a cause to a thermal event becomes increasingly difficult as the nature of the material becomes more complicated. Such is the case with a fully formulated coating which contains a wide range of polymeric and oligomeric materials, as well as various additives. To determine which chemistry is responsible for a particular thermal transition, other analytical techniques are used, frequently in direct combination with the thermal analysis technique.

A coating system

Abstract: A coating system comprising a container (12) having a coating composition, and a roller for applying the coating composition to a surface, the coating composition having a high shear viscosity of between 5.5 to 8.0 poise at 25°C (ICI cone and plate viscometer) and a surface drying time greater than 60 minutes at a temperature of 25°C and a humidity of 50%.

Topical Aminoglutethitnide and Sebum Excretion

Abstract: dissipate quickly once the ointment has been removed tends to support this assumption. The experiment shows that, although the placebo effect can be easily assessed, it cannot readily be separated from the overall efficacy of the corticosteroid preparation. The hydration produced in the placebo situation is an integral part of the total treatment to such a degree that bases producing a high placebo response are preferable since these are most likely to create a more favourable situation for the penetration of the corticosteroid, than those producing a low placebo response. Therefore the high placebo responses observed in the previous test do not invalidate the use of the blanching test as a useful laboratory technique for assessing the activity of the corticosteroid preparations.