Ketone resin solubility

A varnish is often appHed on top of the paint layers. A varnish serves two purposes as a protective coating and also for an optical effect that enriches the colors of the painting. A traditional varnish consists of a natural plant resin dissolved or fused in a Hquid for appHcation to the surface (see Resins, natural). There are two types of varnish resins hard ones, the most important of which is copal, and soft ones, notably dammar and mastic. The hard resins are fossil, and to convert these to a fluid state, they are fused in oil at high temperature. The soft resins dissolve in organic solvents, eg, turpentine. The natural resin varnishes discolor over time and also become less soluble, making removal in case of failure more difficult (see Paint and FINNISH removers). Thus the use of more stable synthetic resins, such as certain methacrylates and cycHc ketone resins, has become quite common, especially in conservation practice. 

Primers, sometimes called self-adhesive resins or adhesion promoters, can be used to improve adhesion, for instance Self-Adhesive Resin EP 2440, Hills AG, Marl. The resin is soluble in many different solvents and can thus be readily applied before the adhesive. It is also used as an adhesion promoter for polyester and ketone resins. Other adhesion promoters include 0.5% silanes in methanolic solution. They are mixed directly into the adhesives or applied to the adhesion smfaces. 

The hydroxyl containing terpolymers have solubilities similar to those of the medium-to-low molecular weight vinyl chloride-vinyl acetate copolymers. This resin solubility system is shown in Figure 18. The ketones evaluated were methyl n-butyl ketone and methyl n-propyl ketone. 

The neutral behavior of poly(vinyl acetate) allows the use of all conventional pigments. Poly(vinyl acetate) is highly compatible with ester-soluble nitrocellulose and improves the adhesion and lightfastness of the latter. Poly(vinyl acetate) can also be readily combined with phenolic resins, ketone resins, and colophony resins. 

Diacetone alcohol [123-42-2] (4-hydroxy-4-methyl-2-pentanone) is an almost odorless ketone alcohol that is weakly acidic as a result of rearrangement to the enol form. It is miscible with water and organic solvents except aliphatic hydrocarbons. It acts as a good solvent for cellulose esters and ethers, alcohol-soluble resins, castor oil, and plasticizers. Poly(vinyl acetate) and chlorinated rubber are partially dissolved or swollen. Polystyrene, poly(vinyl chloride), vinyl chloride copolymers, dam-ar resins, resin esters, rubber, bitumen, mineral oils, ketone resins, and maleate resins are insoluble. Diacetone alcohol is used as a high boiler in stoving enamels to improve flow and gloss. 

Ethyl triglycol [112-50-5] [2-(2-ethoxyethoxy)ethoxy]ethanol, triethylene glycol monoethyl ether] is an almost colorless, neutral, mild-smelling liquid with a low hygroscopicity. It is soluble in water and most organic solvents, but is only partially miscible with aromatic and aliphatic hydrocarbons. Ethyl triglycol dissolves cellulose nitrate, shellac, colophony, ketone resins, maleate resins, chlorinated rubber, alkyd resins, and many other paint resins. It does not dissolve cellulose acetate, poly(vinyl chloride), vinyl chloride copolymers, fats, oils, and rubber. 

N.N-Dimethylformamide [68-12-2] (DMF) [14.276] is miscible with water and organic solvents except aliphatic hydrocarbons. It is a good high-boiling solvent for cellulose esters, cellulose ethers, poly(vinyl chloride), vinyl chloride copolymers, poly(vinyl acetate), polyacrylonitrile, polystyrene, chlorinated rubber, polyacrylates, ketone resins, and phenolic resins. Alkyd resins and resin esters are partially soluble. Dimethylformamide does not dissolve polyethylene, polypropylene, urea-formaldehyde resins, rubber, and polyamides. It is used as a solvent in printing inks, for polyacrylonitrile spinning solutions [14.277], and as a solvent in the synthesis of acetylene. 

Cyclic ketone resins n. Cyclohexanone is the primary constituent of these resins, and it is condensed either by the action of alkalis or acids. Mixed condensation products of cyclohexanone and aldehydes are also resinous. The cyclic ketone resins, which are available commercially are notable chiefly by reason of their extremely pale colors and characteristic smell. They are usually very readily soluble in vegetable oils. 

FIGURE A3.20 Solubility of a ketone resin (Ketone Resin N BASF), manufacturers data. 

FIGURE A3.21 Solubility of a ketone resin (MS2A Linden). Data kindly provided by Dr Greg Smith and Classes of 2009, 2010 and 2011 of the Art Conservation Department at Buffalo State College. 

IManila Copal. The Manilas are collected in Indonesia and the Philippines. They are soluble in alcohols and ketones, and insoluble in hydrocarbons and esters. The resins soften between 81—90°C and have acid numbers of 110—141. Principal uses are in coatings and varnishes. 

The (9-cresol novolaks of commercial significance possess degrees of polymerization, n, of 1.7—4.4 and the epoxide functionaUty of the resultant glycidylated resins varies from 2.7 to 5.4. Softening points (Durran s) of the products are 35—99°C. The glycidylated phenol and o-cresol—novolak resins are soluble in ketones, 2-ethoxyethyl acetate, and toluene solvents. The commercial epoxy novolak products possess a residual hydrolyzable chlorine content of <0.15 wt% and a total chlorine content of ca 0.6 wt % (Table 2). 

Being either brittle or soft, these resins do not have the properties for moulding or extrusion compounds. These are, however, a number of properties which lead to these resins being used in large quantities. The resins are chemically inert and have good electrical insulation properties. They are compatible with a wide range of other plastics, rubbers, waxes, drying oils and bitumens and are soluble in hydrocarbons, ketones and esters. 

Purely aromatic ketones generally do not give satisfactory results pinacols and resinous products often predominate. The reduction of ketonic compounds of high molecular weight and very slight solubility is facilitated by the addition of a solvent, such as ethanol, acetic acid or dioxan, which is miscible with aqueous hydrochloric acid. With some carbonyl compounds, notably keto acids, poor yields are obtained even in the presence of ethanol, etc., and the difficulty has been ascribed to the formation of insoluble polymolecular reduction products, which coat the surface of the zinc. The adffition of a hydrocarbon solvent, such as toluene, is beneficial because it keeps most of the material out of contact with the zinc and the reduction occurs in the aqueous layer at such high dilution that polymolecular reactions are largdy inhibited (see Section IV,143). 

The soluble catalytic species was generated in situ by reaction of the polybinaphthyl resin (19) with diethylzinc prior to addition of the unsaturated ketone and tBuOOH (Scheme 4.11). After completion of the reaction, the soluble polymer had to be precipitated by addition of methanol. Yields were reported in the range between 67 to 95% [77]. 

Phenoxy resins may be extruded, injection-molded, and blow-molded to produce pipe, sporting goods, containers, and appliance housings. Since phenoxy resins are soluble in methyl ethyl ketone, they have been used as adhesives and cross-linkable protective coatings. 

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