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Werniksy mastyksowe i damarowe

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The intention of the paper is to characterise the past and future of two kinds of varnishes: based on gum mastic and dammar resin. The author presents information on the origin of mastic and dammar, their commercial class, physical and chemical properties as well as resistance to aging. Special attention is paid to the influence of certain additives, such as solvents, matting agents, plasticisers, UV absorbers and HALS photostabilisers. The article describes commercially available varnishes and mentions assorted non-commercial formulas.
EN
The article discusses basic properties of Paraloid B-72 such as solubility, miscibility with softening agents and thermoplastic resins, behaviour during heating (temperatures of vitrification, softening, plasticization and disintegration). Examples of major applications and detailed literature on the use of Paraloid B-72 have also been given.
EN
The article refers to two groups of picture varnishes, which were evaluated as an alternative solution to classical varnishes based on mastic and dammar. The author describes the physical and chemical properties of the resins, their resistance to light, and possibilities of stabilisation. Trade varnishes and proposals by many authors are also presented. The author underlines the fact that varnishes prepared from hydrogenated hydrocarbon resins, high quality white spirit and HALS stabilisers are more stable than most of the trade varnishes produced from mastic, dammar and cyclohexanone resins.
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Werniksy akrylowe

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The article presents the properties of frequently used acrylic varnishes, with special mention of the history of their application and the state of current knowledge. The author indicates assorted ways in which the producers obtain a certain degree of matte effects (beeswax, monocrystal wax, colloidal silica), increase resilience against the impact of light (UV absorbents, photostabilisers fromthe HALS group), and employ different organic solvents, enabling the regulation of the time needed for drying. The presented article is a survey, containing the results of heretofore unpublished studies conducted by the authors.
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The biggest shortcoming of epoxide resins is their yellowing under the effect of light. The resins which turn yellow easily are mainly the cheapest, universally available and widely applied epoxide resins obtained from dian and epichlorohydrin. Until now chemists have not been able to establish the mechanism of their yellowing, although it is well-known that this process depends largely on a chemical structure of resins, their kind and quantity of auxiliary substances (dissolvents, softeners, accelerators, hardening agents and conditions of hardening). A vast number of such products is offered on the market, some of which show very high resistance to yellowing, whilst the resistance of others is very low. The article mentions products with exceptionally high resistance to yellowing under the effect of temperature and also describes light fastness of some epoxide compounds made by Ciba-Geigy. Attention has been paid to the fact that improper hardening reduces light fastness of hardened resins.
EN
The article presents the properties of the cyclohhexane resins with particular attention paid to polycyclohexane produced under the brand name of Laropal К 80. In connection with the universal application of this resin for the production of painting varnish ( for final and retouching purposes ), the ways of increasing their flexibility have been discussed as well as their resistance to the processes of thermo-- and photo-oxidation which result in yellowing, increased fragility, and loss of solubility in liquids of little polarity ( for example, in purified gasoline ). The article stresses the optical merits of the cyclohexane varnishes, similar to those which are possessed by dammar and mastic varnishes in relation to the layer of oil point.
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The article discusses basic properties of PVA such as solubility, misoibility with plastidizens, behaviour during heating and resistance to ageing. Trade names and producers, examples of major applications and detailed literature on the use of PVA have also been given.
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The article describes properties and use of fluoric resins in the conservation of stone historic objects. This group of resins covers substances with a different structure which may be regarded fluoro-derivatives of other resins. Their properties are determined by the structure of the chain and number of carbon-fluorine bondings which are much stronger than bondings of carbon and hydrogen. Fluoric resins that have no bondings of carbon and hydrogen, i.e. the so-called perfluoropolymers, show the highest thermal and chemical resistance. Still, many of them do not dissolve in any solvent. Soluble fluoric resins include, in the first place, co-polymers of vinylidene fluoride with other fluor-containing monomers. Co-polymers of vinylidene fluoride and trifluorochloroethylene demonstrate a good resistance to the effect of atmospheric factors and microorganisms; they neutralize the action of corrosive effects including concentrated acids. They are produced in the USSR and USA. Italy makes perfluorovinyl polyethers which show high thermal and chemical resistance; they are also resistant to light and microorganisms. Apart from that, they are markedly hydrophobic.
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P ro p e rtie s of polymers an d co-polymers of b u ty l m e th ac ry la te h av e been discussed. A p a rtic u la r a tte n tio n h a s been p a id to dissolubility, e la s tic ity an d re s istan c e to lig h t an d microorganisms. Major ap p lic a tio n s an d d e ta iled b ib lio g rap h y h av e been given. Th e a rtic le contains also a list of m a jo r tra d e b ra n d s a n d m a n u fa c tu re rs of th e re s in s described.
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In the article the tw o most important cellulose esters are discussed: nitrocellulose and acetylcellulose. Their physical and chemical properties are given. Their general use and their use in historical object preservation are described, with a list of reference works being included. Particular attention is paid to the very small stability of nitrocellulose and the problems connected with the storage and preservation of nitrocellulose photographic film.
EN
The article specifies physical, chemical and mechanical properties of polyvinyl acetate such as the temperature of vitrification, softening and thermal decomposition, solubility, resistance to chemicals and ageing under the effect of atmospheric and biological factors. Various forms of this polymer (solid substances, solutions and water dispersions) have been discussed and major trade and manufactures’ names listed. In a similar way copolymers of polyvinyl acetate and ethylene, acrylic esters and other monomers have been described.
EN
The paper is addressed to conservators and restorers of works of art. It deals with properties and use of ethylene polyglycols. In the part discussing properties a special attention has been paid to the effect of molecular mass, and in the part devoted to the application to the conservation of archaeological findings. The paper lists major trade products and singles out polyglycols made by Hoechst AG.
EN
The article discusses the features and use of artificial resins obtained by ethirification of cellulose. Apart from the two generally known and frequently used ethers: methyl cellulose and carboxymethyl cellulose, other ethers were pointed out, such as ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and benzyl cellulose. The commercial names and names of producers of the more important cellulose ethers were given, with literature concerning their use in the conservation of paper, natural fibre fabrics and paintings done in distemper.
EN
The availability on the market of a big numer of ready-made paints, substances and materials with different resistance to light makes it necessary to have them examined thoroughly, especially with a view to the requirements of conservation and restoration of works of art. Because ultra-violet radiation exerts a great effect upon the paramemeters of the colouring of some acrylic paints, there has been developed a method of the so-called quantitative expression of colours; it consists in establishing parameters of the colouring of artistic paints. The method is based on a wellknown law of Grossman. According to it, any colour P can be produced by mixing three basic colours: А, В, С in quantities X, Y, Z. Thus P = XA+YB+ZC. Colours А, В, С are basic to the effect that none of them can be obtained by mixing the remaining two. The method of establishing parameters of the colouring makes it possible to (1) quickly and objectively state changes occurring under the effect o f ultra-violet radiation, (2) carry out comparative studies of paints made by different manufacturers, (3) examine chainges taking place under the effect of substances used for conservation and restoration, and finally (4) record changes in the colouring of individual parts of works. Another essential advantage of the method is the possibility to use measuring equipment that is easy of access and simple to operate. It is also very useful in describing the condition of historic works of art and their protection.
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