Abstract: This invention relates to a resin preparable by reaction of a phenol/formaldehyde novolak with tetraethyl orthosilicate in a mass ratio above 28:1, wherein the phenol of the phenol/formaldehyde novolak is substituted or unsubstituted hydroxybenzene or a mixture of two or more such phenols, and to a particulate material coated with said resin. Said particles can be used e.g. in the shell molding process for the production of shell molds and shell cores; and as proppants for use in the hydraulic fracturing process.

Abstract: This invention relates to a resin preparable by reaction of a phenol/formaldehyde novolak with tetraethyl orthosilicate in a mass ratio above 28:1, wherein the phenol of the phenol/formaldehyde novolak is substituted or unsubstituted hydroxybenzene or a mixture of two or more such phenols, and to a particulate material coated with said resin. Said particles can be used e.g. in the shell molding process for the production of shell molds and shell cores; and as proppants for use in the hydraulic fracturing process.

Abstract: This invention describes the use of higher fatty acid methyl esters, i.e. of methyl monoesters of fatty acids having a carbon chain of 12 C atoms or more, for example of rapeseed oil methyl ester, as solvent for the individual or both components of polyurethane binders for molding materials used in foundry technology, the components of which comprise a phenolic resin which contains free OH groups and a polyisocyanate as a reaction participant. The fatty acid methyl esters can be the sole solvent. However, they also can be used, at least for the polyisocyanate, together with a high boiling aromatic hydrocarbon, whereby the amount of the fatty acid methyl ester should exceed the amount of the hydrocarbon, and they can be used, at least for the phenolic resin, together with a solvent of higher polarity. The use of fatty acid methyl esters entails considerable benefits.

Abstract: Two-component binder system with reduced release of aromatic compounds during foundry operations, the system consisting of a phenol resin component and a polyisocyanate component, the phenol resin component comprising a phenol resin having at least two OH groups per molecule and the polyisocyanate component comprising a polyisocyanate having at least two isocyanate groups per molecule, wherein at least the phenol resin component contains a solvent, and wherein at least one of the phenol resin component and the polyisocyanate component comprises a solvent selected from the group consisting of alkyl silicates, alkyl silicate oligomers and mixtures thereof.

Abstract: This invention describes the use of higher fatty acid methyl esters, i.e. of methyl monoesters of fatty acids having a carbon chain of 12 C atoms or more, for example of rapeseed oil methyl ester, as solvent for the individual or both components of polyurethane binders for molding materials used in foundry technology, the components of which comprise a phenolic resin which contains free OH groups and a polyisocyanate as a reaction participant. The fatty acid methyl esters can be the sole solvent. However, they also can be used, at least for the polyisocyanate, together with a high boiling aromatic hydrocarbon, whereby the amount of the fatty acid methyl ester should exceed the amount of the hydrocarbon, and they can be used, at least for the phenolic resin, together with a solvent of higher polarity.The use of fatty acid methyl esters entails considerable benefits.

Abstract: The binder serves to produce foundry moulds and comprises a solution (preferably an aqueous solution) of aldehyde reactive phenol substances and gaseous acetals (preferably dimethyl formal) as reaction partners and strong acids, e.g. sulphuric acid and sulphonic acids as a catalyst. The acetal is in this system hydrolysed by the acid, the basic aldehyde being formed, which will react with the aldehyde reactive phenol substance accompanied by cross-linking. The acid serves thereby simultaneously as a cross-linking catalyst. In principle, it is possible to regard as "aldehyde reactive phenol substances" any phenolic compounds which can in the acid range cross-link more or less spontaneously with aldehydes. Preferably, these are resorcinol or resorcinol products, e.g. resorcinol pitch or precondensates formed with a shortfall of aldehyde, e.g. based on resorcinol formaldehyde, phenol resorcinol formaldehyde or resorcinol melamine formaldehyde.To produce foundry moulds, a granular basic moulding material, e.g.

Abstract: This invention relates to a mould material binding agent system for the manufacture of foundry mould parts. This binding agent system contains, as components, a solution of a phenol-containing polyol having at least two OH-groups in the molecule and a polyisocyanate, optionally in the form of a solution, having at least two NCO-groups in the molecule, which react with each other to a cold-hardening binding agent with formation of polyurethane. As polyisocyanate component there are used (optionally phenyl-substituted) diphenyl-4,4', diisocyanates having a content of more than 10% by wt. (referred to the total quantity of polyisocyanate), preferably more than 20% by wt., of the isomeric diphenyl-2,4'-diisocyanate (likewise optionally phenyl-substituted), which also contain an addition of a small quantity of acid chlorides and/or chlorosilanes.

Abstract: This invention relates to a mould material binding agent system for the production of foundry mould parts. This binding agent system contains as components a solution of a phenol-containing polyol having at least two OH groups in the molecule and a polyisocyanate, optionally also in the form of a solution, having at least two NCO groups in the molecule, which react with one another to a cold-hardening binding agent with formation of polyurethane. According to the invention there is also added to the polyisocyanate component a chlorosilane, which for example may comprise one or more compounds of the group trimethyl chlorosilane, dimethyl dichlorosilane, methyl trichlorosilane, tetrachlorosilane, diethyl chlorosilane, vinyl trichlorosilane and diphenyl dichlorosilane. The added quantity is preferably 0.01-2% by wt. relative to the polyisocyanate component.

Abstract: This relates to a bonding agent which is used for the production of molded foundry parts and which is composed of two basic components which harden out cold in the mixture of the molded material in the presence of a catalyst under the formation of polyurethane. One basic component is a polyol in the form of a solution of a co-condensate containing an OH group consisting of phenol, aldehyde and an alkyl phenyl siloxane with a contents of at least 3% by weight in free OH groups, if applicable in mixture with a phenol aldehyde condensate containing an OH group, and the second basic component is a polyisocyanate likewise dissolved under normal conditions. Appropriately the solvent has a content in vegetable oils, preferably castor oil.

Abstract: A cold setting molding material which includes sand and a polyurethane binder with the polyol portion of the polyurethane reaction mixture containing a tertiary amino group and phenolic hydroxyl groups.