DK168366B1

DK168366B1 - Hardenable binding agent material, a process for producing a cast product using the material, and an additive material for a phenolic resin-polyisocyanate binding agent system

Info

Publication number: DK168366B1
Application number: DK53082A
Authority: DK
Inventors: Tom Mitsopoulos; Satish Jhaveri; Charles Lui
Original assignee: Valvoline Oil & Chem
Priority date: 1982-02-08
Filing date: 1982-02-08
Publication date: 1994-03-21
Also published as: DK53082A

Description

DK 168366 B1DK 168366 B1

Opfindelsen angår bindemiddelmaterialer, der er egnede til anvendelse ved fremstilling af støberiprodukter til metalstøbninger eller lignende produkter.The invention relates to binder materials suitable for use in the manufacture of foundry products for metal castings or similar products.

Ved fremstillingen af metalgenstande ved støbning i et 5 støberi fremstilles der et støberiprodukt ved blanding af et passende bindemiddelmateriale med et tilslag såsom sand, formning af blandingen i en støbeform og hærdning af blandingen således, at der dannes et selvunderstøttende støberiprodukt.In the manufacture of metal objects by casting in a foundry, a foundry product is prepared by mixing an appropriate binder material with a aggregate such as sand, forming the mixture in a mold and curing the mixture to form a self-supporting foundry product.

Skønt det i mange år har været nødvendigt at tilføre var-10 me ved udførelse af hærdningstrinnet, er der for nylig blevet udviklet bindemiddelmaterialer, der kan hærdes ved stuetemperatur, og denne forbedring repræsenterer et meget signifikant fremskridt på området. De metoder, ved hvilke der anvendes sådanne bindemiddelmaterialer, er blevet kendt som "no-bake"-sy-15 stemer eller koldboks-systemer.Although it has been necessary to add heat for many years in carrying out the curing step, binder materials which can be cured at room temperature have recently been developed and this improvement represents a very significant advance in the field. The methods by which such binder materials are used have become known as "no-bake" systems or cold box systems.

Eksempelvis er der i US patentskrift nr. 3.409.579 beskrevet et bindemiddelmateriale, der kan hærdes ved stuetemperatur, dvs. uden at der kræves anvendelse af varmetilførsel. Bindemiddelmaterialet omfatter en harpikskomponent, 20 en hærderkomponent og et hærdningsmiddel. Harpikskomponenten omfatter en opløsning i et organisk opløsningsmiddel af en ikke-vandig, phenolisk harpiks, hærderkomponenten omfatter et flydende polyisocyanat indeholdende mindst to isocyanat-grupper, og hærdningsmidlet omfatter en tertiær amin. En 25 foretrukken harpiks er beskrevet i US patentskrift nr.For example, U.S. Patent No. 3,409,579 discloses a binder material which can be cured at room temperature, i.e. without the use of heat supply. The binder material comprises a resin component, a curing component and a curing agent. The resin component comprises a solution in an organic solvent of a non-aqueous phenolic resin, the hardener component comprises a liquid polyisocyanate containing at least two isocyanate groups, and the hardener comprises a tertiary amine. A preferred resin is described in U.S. Pat.

3.485.797.3485797.

En støberiblanding fremstilles ved blanding af en sammenbindende mængde af harpikskomponenten og hærderkomponenten med tilslag indeholdende sand som en væsentlig bestanddel, idet den 30 sammenbindende mængde af harpikskomponent og hærderkomponent udgør op til 10% af vægten af tilslaget. Støberiblandingen formes derpå i en støbeform og hærdes ved at lede hærdningsmidlet i form af en tertiær amin gennem støberiblandingen i form af en gas. Hærdningsmidlet i form af den tertiære amin katalyserer 35 en tværbindingsreaktion ved stuetemperatur mellem den phenoli- DK 168366 B1 2A foundry blend is prepared by mixing a bonding amount of the resin component and the curing component with aggregates containing sand as an essential ingredient, the 30 binding amount of the resin component and curing component constituting up to 10% by weight of the aggregate. The casting mixture is then formed into a mold and cured by passing the curing agent in the form of a tertiary amine through the casting mixture in the form of a gas. The curing agent in the form of the tertiary amine catalyzes a cross-linking reaction at room temperature between the phenolic and the

OISLAND

ske harpikskomponent og isocyanat-hærderkomponenten til dannelse af en fast polymer med det resultat, at der dannes et selvunderstøttende støberiprodukt på forholdsvis kort tid, hvilket kan være så lidt som fra ét til fire sekunder.the resin component and the isocyanate hardener component to form a solid polymer result in the formation of a self-supporting foundry product in a relatively short time, which can be as little as one to four seconds.

5 Sådanne "no-bake"- eller koldboks-systemer, der kan hær des ved stuetemperatur, betegner et signifikant fremskridt på området i sammenligning med tidligere systemer, hvor der krævedes varme til hærdningstrinnet, og "no-bake"- eller koldboks--systemer som beskrevet i de ovennævnte US patentskrifter har 10 opnået betydelig kommerciel succes. I forbindelse med sådanne systemer kan der imidlertid stadig foretages forbedringer. Eksempelvis kan støberiproduktet undergå et uacceptabelt tab af styrke, når det opbevares under betingelser, der involverer en høj fugtighedsgrad. Der kan også forekomme hurtige tab af styr-15 ke, når støberiproduktet nedsænkes i vandbaserede ildfaste materialer og derefter tørres i en ovn. Denne procedure kan udføres, når støberiproduktet anvendes til metalstøbning, til formindskelse af sandsynligheden for, at metal trænger ind i støbningen, eller at tilslaget (sædvanligvis sand) påbrænder på me-20 tallet. Det vil således være fordelagtigt, såfremt bibeholdelsen af styrken kunne forbedres under sådanne omstændigheder.Such "no-bake" or cold-box systems that can be cured at room temperature signify a significant advance in the field compared to previous systems where heat was required for the curing step and "no-bake" or cold-box - systems as described in the aforementioned US patents have achieved considerable commercial success. However, for such systems improvements can still be made. For example, the foundry product may undergo an unacceptable loss of strength when stored under conditions involving a high humidity. Rapid loss of strength may also occur when the foundry product is immersed in water-based refractory materials and then dried in an oven. This procedure can be carried out when the foundry product is used for metal casting, to reduce the likelihood of metal entering the casting or the slag (usually sand) burning on the metal. Thus, it would be advantageous if the retention of strength could be improved in such circumstances.

Grunden til sådanne tab af styrke forstås ikke fuldstændigt, men én teori er som følger: det menes, at den blandede phenolharpiks og isocyanat-hærder, som dækker kornene i til-25 slaget, polymeriseres under hærdningstrinnet til dannelse af broer ved kontaktpunkterne mellem individuelle korn af tilslaget, idet polymerbroerne bindes til tilslagskornene, hvorved der dannes en kohæsiv masse. Under denne proces uddrives der imidlertid opløsningsmiddel fra den polymeriserende masse, så-30 ledes at harpiksen ikke kontinuerligt dækker kornene i tilslaget. Når opløsningsmidlet fordamper, kan fugtighed trænge ind i den kohæsive masse og bevæge sig ind i arealer med diskontinuitet eller i spalter i den polymeriserede harpiksfilm. Over et tidsrum kan denne fugtighed progressivt trænge ind mellem 35 overfladen af kornene og den vedhængende polymeriserede har- DK 168366 B1 3 piks, hvorved bindingen svækkes. Det skal understreges, at dette blot er én mulig forklaring.The reason for such loss of strength is not completely understood, but one theory is as follows: It is believed that the mixed phenolic resin and isocyanate hardener, which covers the grains of the coating, is polymerized during the curing step to form bridges at the contact points between individual grains of the aggregate, bonding the polymer bridges to the aggregate grains, thereby forming a cohesive mass. However, during this process, solvent is expelled from the polymerizing mass so that the resin does not continuously cover the grains in the aggregate. As the solvent evaporates, moisture can enter the cohesive mass and move into areas of discontinuity or in gaps in the polymerized resin film. Over a period of time, this moisture may progressively penetrate between the surface of the grains and the pendant polymerized resin, thereby weakening the bond. It should be emphasized that this is just one possible explanation.

De nævnte, kendte støberiprodukter kan også have dårlige formslip-karakteristika på grund af, at den hærdede har-5 piks hænger ved støbeformens overflade. Sådanne støberiprodukter kan også have en forholdsvis ringe øjeblikkelig styrke, dvs. styrke umiddelbart efter dannelse i støbeformen, hvilket nødvendiggør proportionalt høje mængder harpiks i tilslaget for at opnå, at det hærdede støberiprodukt kan håndteres tilfreds-10 stillende efter udstødning fra formen. Også her ville det være fordelagtigt, såfremt der kunne tilvejebringes forbedringer med hensyn til formslipegenskaber og øjeblikkelige styrker.Said known molding products may also have poor mold slip characteristics due to the cured resin adhering to the mold surface. Such foundry products may also have a relatively low instantaneous strength, i. strength immediately after mold formation, which requires proportionally high amounts of resin in the aggregate to ensure that the cured foundry product can be satisfactorily handled after ejection from the mold. Here too, it would be advantageous if improvements could be provided in terms of mold-grinding properties and instantaneous strengths.

I GB offentliggørelsesskrift nr. 2.050.400 er der beskrevet phenolisk harpiks-polyisocyanat-bindemiddelsystemer 15 til støbematerialer med forbedret kollapsibilitet og udryst-ningsegenskaber ved anvendelse ved støbning af metaller med lavt smeltepunkt, f.eks. aluminium, og disse bindemiddel-systemer indeholder en tørrende olie ud over den phenoliske harpiks og polyisocyanat. De foretrukne bindemiddelsystemer, 20 der er beskrevet i det nævnte GB offentliggørelsesskrift, er todelte systemer indeholdende den phenoliske harpiks opløst i et organisk opløsningsmiddel som en første pakning og isocyanatet i blanding med den tørrende olie som en anden pakning.GB Publication No. 2,050,400 discloses phenolic resin polyisocyanate binder systems 15 for molding materials with improved collapsibility and shaking properties when used in low melting point metals, e.g. aluminum, and these binder systems contain a drying oil in addition to the phenolic resin and polyisocyanate. The preferred binder systems described in said GB disclosure are two-part systems containing the phenolic resin dissolved in an organic solvent as a first package and the isocyanate in admixture with the drying oil as a second package.

25 Den foreliggende opfindelse bygger på den erkendelse, at der kan opnås yderligere forbedringer, navnlig med hensyn til støbeformmaterialernes slipegenskaber og øjeblikkelige styrkeegenskaber, såfremt bindemiddelsystemet omfattende den phenoliske harpiks og polyisocyanat ikke blot indeholder 30 en tørrende olie, men også, ud over den allerede nævnte phenoliske harpiksbestanddel, indeholder en yderligere mængde phenolisk harpiks, der er opløst i og partielt tværbundet med den tørrende olie. I den følgende diskussion behandles blandingen af den tørrende olie og den olieopløselige pheno-35 liske harpiks opløst deri og partielt tværbundet dermed som en enkelt bestanddel og betegnes her som additivmateriale DK 168366 B1 4 eller som "den yderligere komponent (eller bestanddel)".The present invention is based on the recognition that further improvements can be achieved, in particular with regard to the abrasive properties and instantaneous strength properties, if the binder system comprising the phenolic resin and polyisocyanate contains not only a drying oil but also, in addition to the aforementioned phenolic resin component, contains an additional amount of phenolic resin dissolved in and partially cross-linked with the drying oil. In the following discussion, the mixture of the drying oil and the oil-soluble phenolic resin dissolved therein and partially crosslinked therewith is treated as a single component and is herein referred to as additive DK 168366 B1 4 or as "the additional component (or component)".

En tørrende olie er som bekendt en oxidativ olie, dvs. en umættet olie med dobbeltbindinger. Én mulig forklaring på fordelene ved opfindelsen er, at den polymeriserende 5 masse, der dannes af harpikskomponenten og hærderkomponenten, under hærdningstrinnet uddriver den yderligere komponent til periferien af polymerbroerne, og at den tørrende olie i den yderligere komponent først tværbinder svagt med isocyana-tet i hærderkomponenten, men også udtørrer, hvilket bevirker, 10 at den olieopløselige phenoliske harpiksbestanddel af den yderligere komponent bliver tværbundet med isocyanatet til i det væsentlige eliminering af muligheden for efterladelse af spalter eller huller i den polymeriserede harpiksfilm, som dækker kornene i tilslaget med det resultat, at vand 15 ikke kan trænge ind mellem polymerbroerne og tilslagskornene til svækkelse af bindingen mellem dem. Det skal på ny understreges, at dette blot er én mulig forklaring.As is well known, a drying oil is an oxidative oil, ie. an unsaturated oil with double bonds. One possible explanation for the advantages of the invention is that during the curing step, the polymerizing mass formed by the resin component and the curing component expels the additional component to the periphery of the polymer bridges and that the drying oil in the additional component weakly cross-links with the isocyanate. but also dries, causing the oil-soluble phenolic resin component of the additional component to be crosslinked with the isocyanate to substantially eliminate the possibility of leaving gaps or holes in the polymerized resin film covering the grains of the aggregate with the resultant that water 15 cannot penetrate between the polymer bridges and the aggregate grains to weaken the bond between them. It should be emphasized again that this is just one possible explanation.

Det har vist sig, at man ved at anvende den nævnte yderligere komponent kan opnå, at støberiprodukter eller lignende 20 produkter kan opbevares under fugtige betingelser, hvor der uden den yderligere komponent ville forekomme tab af styrke. Støberiprodukter, der fremstilles under anvendelse af den yderligere komponent, kan også nedsænkes i vandbaserede ildfaste overtræksmaterialer og derpå tørres i en ovn uden sig-25 nifikant tab af styrke, hvorved man væsentligt formindsker de tilfælde af brud, der forekommer med støberiprodukter, der fremstilles uden den yderligere komponent. Anvendelsen af den yderligere komponent kan også formindske sandsynligheden for distortion, hvilket kan forekomme ved de omhandlede behand-30 linger.It has been found that by using said additional component, it is possible to obtain foundry products or similar products to be stored under humid conditions, where loss of strength would occur without the additional component. Foundry products made using the additional component may also be immersed in water-based refractory coating materials and then dried in an oven without significant loss of strength, thereby substantially reducing the occurrence of fractures occurring with foundry products produced without the additional component. The use of the additional component may also reduce the likelihood of distortion, which may occur in the treatments in question.

Med den foreliggende opfindelse kan der også opnås andre fordele. Eksempelvis kan den yderligere komponent forbedre strømmedygtigheden af sandet, når bindemiddelmaterialet blandes dermed, således at der kan fremstilles tættere støbe-35 riprodukter, hvilket er en fordel ved metalstøbning. Ydermere DK 168366 B1 5 kan det være lettere at frigøre støberiproduktet fra formen.The present invention also provides other advantages. For example, the additional component may improve the flowability of the sand when the binder material is blended therewith, so that denser casting products can be produced, which is an advantage of metal casting. In addition, it may be easier to release the foundry product from the mold.

Den yderligere komponent kan også bidrage til at forbedre den øjeblikkelige styrke af støberiproduktet, formodentlig på grund af tværbindingen af den phenoliske harpiks i den yderlige-5 re komponent med isocyanat-hærderkomponenten.The additional component may also help to improve the instantaneous strength of the foundry product, presumably due to the cross-linking of the phenolic resin in the additional component with the isocyanate hardener component.

Opfindelsen angår således et hærdel igt bindemiddel-materiale til formbare støberiblandinger indeholdende en blanding af en ikke-vandig phenolisk harpiks i opløsning i et organisk opløsningsmiddel, et flydende polyisocyanat og 10 en tørrende olie, og dette materiale er ejendommeligt ved, at der som den tørrende oliebestanddel er anvendt en tørrende olie, der er blevet tværbundet til en viskositet i området fra E til M på Gardner Hold-bobleviskosimeterskalaen ved for-reaktion med fra 10 til 30 vasgtprocent af en olieopløse-15 lig phenolisk harpiks, beregnet på den totale vægt af den olieopløselige phenoliske harpiks og den tørrende olie, til dannelse af direkte bindinger mellem den tørrende olie og den olieopløselige harpiks, hvilken olieopløselige phenoliske harpiks er den samme som eller forskellig fra den phenoliske 20 harpiksbestanddel i bindemidlet, hvorhos den tørrende oliebestanddel inklusive det for-reagerede olieopløselige phenoliske harpiksbindemiddel er til stede i bindemiddelmaterialet i en mængde fra 1 til 20%, beregnet på vægten af den ikke--vandige phenoliske harpiks.The invention thus relates to a hardenable binder material for moldable molding compositions containing a mixture of a non-aqueous phenolic resin in solution in an organic solvent, a liquid polyisocyanate and a drying oil, and this material is characterized in that as the drying agent. oil component is used a drying oil which has been crosslinked to a viscosity in the range of E to M on the Gardner Hold bubble viscometer scale by pre-reaction with from 10 to 30% by weight of an oil-soluble phenolic resin, based on the total weight of the oil-soluble phenolic resin and the drying oil, to form direct bonds between the drying oil and the oil-soluble resin, which oil-soluble phenolic resin is the same or different from the phenolic resin component of the binder, wherein the drying oil component including the preactivated oil-soluble phenolic resin binder is present in the binder material in an amount from 1 to 20%, based on the weight of the non-aqueous phenolic resin.

25 Harpikskomponenten, hærderkomponenten og hærdningsmid let kan være som beskrevet i de ovennævnte US patentskrifter.The resin component, hardener component, and curing agent can readily be as described in the aforementioned US patents.

Phenolharpiksen i den yderligere komponent er med fordel et kondensationsprodukt af en phenol med den almene formel 30The phenolic resin in the additional component is advantageously a condensation product of a phenol of the general formula 30

OHOH

A----BA ---- B

35 C35 ° C

DK 168366 B1 6 i hvilken A, B og C hver er hydrogen, carbonhydridgrupper, carbonhydridoxygrupper eller halogen, og et aldehyd med den almene formel RCHO, i hvilken R er hydrogen eller en carbon-hydridgruppe med 1-8 carbonatomer.In which A, B and C are each hydrogen, hydrocarbon groups, hydrocarbon oxy groups or halogen, and an aldehyde of the general formula RCHO in which R is hydrogen or a hydrocarbon group having 1-8 carbon atoms.

5 Mængden af yderligere komponent er fra 1 til 20 vægt procent af harpikskomponenten, fortrinsvis fra 1 til 10 vægtprocent af harpikskomponenten.The amount of additional component is from 1 to 20% by weight of the resin component, preferably from 1 to 10% by weight of the resin component.

Den tørrende olie kan være mindst én af olierne udvalgt fra gruppen bestående af ricinusolie, tungolie, hør-10 frøolie, oiticicaolie, safflorolie og sojabønneolie. Den tørrende olie kan omfatte en blanding af ricinusolie og tungolie og kan indeholde fra 3 til 4 vægtdele ricinusolie for hver del tungolie.The drying oil may be at least one of the oils selected from the group consisting of castor oil, heavy oil, flaxseed oil, essential oil, safflower oil and soybean oil. The drying oil may comprise a mixture of castor oil and heavy oil and may contain from 3 to 4 parts by weight of castor oil for each part of heavy oil.

Som angivet er den tørrende oliebestanddel partielt 15 tværbundet ved for-reaktion med den yderligere olieopløselige harpiks. Graden af tværbinding vil være således, at den tørrende oliebestanddel får en viskositet ved 25°C i området fra E til M, fortrinsvis fra G til K, målt på Gardner Hold--bobleviskosimeterskalaen.As indicated, the drying oil component is partially cross-linked by pre-reaction with the additional oil-soluble resin. The degree of crosslinking will be such that the drying oil component has a viscosity at 25 ° C in the range from E to M, preferably from G to K, as measured on the Gardner Hold bubble viscometer scale.

20 Opfindelsen angår også en hærdelig støberiblanding, der er ejendommelig ved,at den indeholder en hovedmængde af uorganisk tilslag og en effektiv bindende mængde af op til 40 vægtprocent af det ovennævnte bindemiddelmateriale.The invention also relates to a curable molding composition which is characterized in that it contains a major amount of inorganic aggregate and an effective binding amount of up to 40% by weight of the above binder material.

Opfindelsen angår endvidere en fremgangsmåde til 25 fremstilling af et formet støberiprodukt, og denne fremgangsmåde er ejendommelig ved, at man former den ovennævnte hærdelige støberiblanding og bringer den formede blanding i kontakt med et hærdningsmiddel for bindemidlet.The invention further relates to a method for producing a molded foundry product, and this method is characterized by forming the above-hardenable casting mixture and contacting the molded mixture with a curing agent for the binder.

Opfindelsen angår desuden et additivmateriale til 30 phenolisk harpiks-polyisocyanat-bindemiddelsystemer, kendetegnet ved, at det omfatter en tørrende olie, der er blevet tværbundet til en viskositet (25*C) i området fra E til M på Gardner Hold-bobleviskosimeterskalaen ved reaktion med 10 til 30 vægtprocent af en olieopløselig phenolisk harpiks, 35 beregnet på den totale vægt af additivmaterialet, til dannelse af direkte bindinger mellem den tørrende olie og den DK 168366 Bl 7 olieopløslige harpiks.The invention further relates to an additive material for 30 phenolic resin polyisocyanate binder systems, characterized in that it comprises a drying oil which has been crosslinked to a viscosity (25 ° C) in the range E to M on the Gardner Hold bubble viscometer scale by reaction with 10 to 30% by weight of an oil-soluble phenolic resin, 35 based on the total weight of the additive material, to form direct bonds between the drying oil and the oil-soluble resin.

Blandingen kan hærdes ved at lede et gasformigt hærdningsmiddel gennem blandingen, og det gasformige hærdningsmiddel kan indeholde en tertiær amin. Alternativt kan hærdnings-5 midlet indeholde en flydende katalysator blandet med formmaterialet.The mixture may be cured by passing a gaseous curing agent through the mixture and the gaseous curing agent may contain a tertiary amine. Alternatively, the curing agent may contain a liquid catalyst mixed with the molding material.

Den phenoliske harpiks i den yderligere komponent kan være en novolak eller resolharpiks, og den phenoliske harpiks i harpikskomponenten kan være en polybenzylether-harpiks, der 10 ikke er olieopløselig. Den phenoliske harpiks i den yderligere komponent kan være den samme harpiks som harpiksen i harpikskomponenten, såfremt den er en olieopløselig phenolisk harpiks.The phenolic resin in the additional component may be a novolac or resole resin, and the phenolic resin in the resin component may be a polybenzyl ether resin which is not oil soluble. The phenolic resin in the additional component may be the same resin as the resin in the resin component if it is an oil-soluble phenolic resin.

Ifølge en udførelsesform for opfindelsen er den 15 yderligere komponent en phenolisk harpiks opløst i og delvis tværbundet med en blanding af dehydratiseret ricinusolie og tungolie (Chinawood-olie), idet opløsningen er fortyndet med et egnet organisk opløsningsmiddel såsom mineralsk terpentin. Den yderligere komponent fremstilles ved at sætte findelt phe-20 nolisk harpiks til forvarmet dehydratiseret ricinusolie, idet tungolien tilsættes derefter under tilførsel af yderligere varme til fremkaldelse af delvis tværbinding mellem den phenoliske harpiks og ricinusolien og tungolien. Phenolharpiksen anvendes i en mængde fra 10 til 30 vægtprocent, beregnet på den 25 totale vægt af harpiks og tørrende olie. Mineralsk terpentin tilsættes derpå til nedsættelse af opløsningens viskositet til en passende værdi.According to an embodiment of the invention, the further component is a phenolic resin dissolved in and partially cross-linked with a mixture of dehydrated castor oil and heavy oil (Chinawood oil), the solution being diluted with a suitable organic solvent such as mineral turpentine. The additional component is prepared by adding finely divided phenolic resin to preheated dehydrated castor oil, the heavy oil being then added with the addition of additional heat to induce partial cross-linking between the phenolic resin and the castor oil and the heavy oil. The phenolic resin is used in an amount of from 10 to 30% by weight, based on the total weight of resin and drying oil. Mineral turpentine is then added to reduce the viscosity of the solution to an appropriate value.

Til fremstilling af et støberiprodukt blandes den yderligere komponent med en harpikskomponent indeholdende en opløs-30 ning i et organisk opløsningsmiddel af en ikke-vandig phenolisk harpiks, der kan være den samme harpiks som i oliekomponenten, og en hærderkomponent indeholdende flydende polyisocyanat indeholdende mindst to isocyanatgrupper. Den resulterende blanding blandes med sand-tilslag, og den dannede blanding formgives i 35 en form. Hærdningsmiddel i form af tertiær amin-gas blæses i- DK 168366 B1 8To prepare a foundry product, the additional component is mixed with a resin component containing a solution in an organic solvent of a non-aqueous phenolic resin which may be the same resin as in the oil component and a curing component containing liquid polyisocyanate containing at least two isocyanate groups. . The resulting mixture is mixed with sand aggregate and the resulting mixture is molded into a mold. Curing agent in the form of tertiary amine gas is blown in- DK 168366 B1 8

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gennem ved stuetemperatur. I løbet af sekunder sker der en tværbinding mellem harpikskomponenten og hærderkomponenten til dannelse af et selvunderstøttende produkt.through at room temperature. Within seconds, a cross-linking occurs between the resin component and the curing component to form a self-supporting product.

Den yderligere komponent tilvejebringer modstandsdyg-5 tighed mod tab af selvunderstøttende styrke under fugtige atmosfæriske betingelser, idet den antagne funktion af den yderligere komponent i denne henseende er omtalt i det foregående. Denne funktion viser sig sædvanligvis langsomt ved omgivelsernes temperaturer, f.eks. ca. 4 timer, men kan frem-10 skyndes ved tilførsel af varme, f.eks. den varme, der anvendes til tørring efter neddypning i vandbaserede ildfaste overtræksmaterialer .The additional component provides resistance to loss of self-supporting strength under humid atmospheric conditions, the assumed function of the additional component in this regard being discussed above. This function usually appears slowly at ambient temperatures, e.g. ca. 4 hours, but can be accelerated by the application of heat, e.g. the heat used for drying after immersion in water-based refractory coating materials.

Opfindelsen belyses nærmere Ved hjælp af det følgende udførelseseksempel.The invention will be further elucidated by means of the following embodiment.

15 Til fremstilling af en yderligere komponent forvarmes ca. 7753 kg dehydratiseret ricinusolie til 180°C, og luft gennemledes i en mængde på ca. 0,14 m pr. minut. Der tilsættes derpå øjeblikkeligt ca. 1530 kg for-knust phenolisk harpiks, efterfulgt af ca. 2522 kg tungolie, idet opløsningen 20 derpå opvarmes til 230°C. Opløsningen holdes ved 230°C i ca.15 To prepare an additional component, approx. 7753 kg of dehydrated castor oil to 180 ° C and air is passed in an amount of approx. 0.14 m per minute. Then, approx. 1530 kg of pre-crushed phenolic resin, followed by approx. 2522 kg of heavy oil, the solution 20 being then heated to 230 ° C. The solution is kept at 230 ° C for approx.

1 time til opnåelse af partiel tværbinding af harpiksen med dehydratiseret ricinusolie og tungolie, hvorefter der afkøles til 150°C. Den afkølede opløsning hældes dernæst ud i ca.1 hour to obtain partial cross-linking of the resin with dehydrated castor oil and heavy oil, then cool to 150 ° C. The cooled solution is then poured into ca.

7415 kg mineralsk terpentin til frembringelse af en yderligere 25 komponent med en viskositet ved 25°C i området fra G til K på7415 kg of mineral turpentine to produce an additional 25 component having a viscosity at 25 ° C in the range from G to K of

Gardner Hold-skalaen (ækvivalent med fra 36.000 til 64.000 mPa.s på Brookfield-skalaen). 'Gardner Hold scale (equivalent to from 36,000 to 64,000 mPa.s on the Brookfield scale). '

Der udføres derefter forsøg til sammenligning af støbe-riprodukter, hvori der er anvendt den yderligere komponent, 30 med produkter, hvori der ikke er anvendt en sådan yderligere komponent. Mængden af tilsat yderligere komponent er 10 vægtprocent af harpikskomponenten, og den procedure, der følges med hensyn til fremstillingen af støberiprodukterne, er i øvrigt som beskrevet i de ovennævnte DS patentskrifter. Den 35 yderligere komponent er ikke blandbar med harpikskomponenten eller med hærderkomponenten. Det menes, at dette skyldes den DK 168366 B1 9Experiments are then performed to compare foundry products using the additional component 30 with products in which no such additional component is used. The amount of additional component added is 10% by weight of the resin component and the procedure followed with regard to the manufacture of the foundry products is otherwise as described in the aforementioned DS patents. The additional component is not miscible with the resin component or with the hardener component. It is believed that this is due to DK 168366 B1 9

OISLAND

partielle tværbinding af den phenoliske harpiks med ricinusolien og tungolien i den yderligere komponent.partial cross-linking of the phenolic resin with the castor oil and heavy oil in the additional component.

Trækstyrken af de fremkomne støberiprodukter med og uden den yderligere komponent måles umiddelbart efter frigø-5 relse fra formen (0 minutter), efter 8 minutter, efter 1 time og efter 24 timer. Hvert støberiprodukt anbringes derpå i en støberiatmosfære med fugtige betingelser i 24 timer, og trækstyrken måles ved afslutningen af dette tidsrum.The tensile strength of the found foundry products with and without the additional component is measured immediately after release from the mold (0 minutes), after 8 minutes, after 1 hour and after 24 hours. Each foundry product is then placed in a foundry atmosphere with humid conditions for 24 hours and the tensile strength is measured at the end of this time.

Resultaterne af forsøgene er som følger, idet trækstyr- 2 10 kerne er angivet i kg/cm og, i parentes, i MPa:The results of the experiments are as follows, the tensile strength being given in kg / cm and, in parentheses, in MPa:

Efter 24 timer i O min. 8 min. 1 time 24 timer fugtig atmosfære 2After 24 hours for 0 min. 8 min. 1 hour 24 hours humid atmosphere 2

Ingen yderligere 11,7 14,8 17,0 23,5 4,9 (kg/cm ) 16 komponent (1'15) (1'46) (1'68) <2'31> <°'48> <MPa> 2No additional 11.7 14.8 17.0 23.5 4.9 (kg / cm) 16 component (1'15) (1'46) (1'68) <2'31> <° '48> < MPa> 2

Med yderligere 15,3 23,8 25,9 29,5 14,0 (kg/cm ) komponent (1'5) (2'34) (2'55) (2'91) (1'38) <MPa)With an additional 15.3 23.8 25.9 29.5 14.0 (kg / cm) component (1'5) (2'34) (2'55) (2'91) (1'38) <MPa )

Den signifikante forbedring i styrken af støberiproduk-20 ter fremstillet ifølge opfindelsen ved udsættelse for fugtige betingelser er åbenbar. Støberiprodukterne fremstillet ifølge opfindelsen har også bedre formslipegenskaber, hvilket ses af den kendsgerning, at det ikke er nødvendigt at anvende slipmidlerne, eller i det mindste kun en stærkt nedsat mængde af de slip-25 midler, der er nødvendige, når der ikke anvendes nogen yderligere komponent.The significant improvement in the strength of foundry products made according to the invention by exposure to moist conditions is evident. The foundry products made according to the invention also have better mold-abrasive properties, as is seen by the fact that it is not necessary to use the abrasives, or at least only a greatly reduced amount of the abrasives needed when no further use is used. component.

Yderligere støberiprodukter med og uden den yderligere komponent fremstilles som ovenfor, men med den undtagelse, at hvert produkt umiddelbart efter frigørelsen fra formen var-30 mebehandles i 10 minutter ved 230°C. Trækstyrken af hvert produkt måles dernæst umiddelbart efter varmebehandlingen (0 minutter) , efter 8 minutter, efter 1 time og efter 24 timer. Resultaterne af disse forsøg er som følger: 35 DK 168366 B1 10 0 min. 8 min. 1 time 24 timerAdditional foundry products with and without the additional component are prepared as above, except that immediately after release from the mold, each product is heat treated for 10 minutes at 230 ° C. The tensile strength of each product is then measured immediately after the heat treatment (0 minutes), after 8 minutes, after 1 hour and after 24 hours. The results of these experiments are as follows: 35 DK 168366 B1 10 0 min. 8 min. 1 hour 24 hours

Ingen yderligere komponent 13,0 16,5 18,9 25,2 (kg/cm2) 5 (1,28) (1,62) (1,80) (2,48) (MPa)No additional component 13.0 16.5 18.9 25.2 (kg / cm 2) 5 (1.28) (1.62) (1.80) (2.48) (MPa)

Med yderligere komponent 18,9 27,3 28,7 32,9 (kg/cm2) 10 (1,86) (2,69) (2,83) (3,24) (MPa)With additional component 18.9 27.3 28.7 32.9 (kg / cm 2) 10 (1.86) (2.69) (2.83) (3.24) (MPa)

Det ses således, at en sådan varmebehandling signifikant forbedrer styrken af støberiprodukter fremstillet 15 ifølge opfindelsen.Thus, it is seen that such heat treatment significantly improves the strength of foundry products made according to the invention.

Claims

A curable binder material for moldable molding ribs containing a mixture of a non-aqueous phenolic resin in solution in an organic solvent, a liquid polyisocyanate and a drying oil, characterized in that a drying oil is used as the drying oil component. which have been crosslinked to a viscosity in the range of E to M on the Gardner Hold Bubble Cosimeter Scale by pre-reaction with from 10 to 30% by weight 10% of an oil soluble phenolic resin, based on the total weight of the oil soluble phenolic resin and the drying oil, to form direct bonds between the drying oil and the oil-soluble resin, the oil-soluble phenolic resin being the same as or different from the phenolic resin component of the binder, wherein the drying oil component including the preactivated oil-soluble phenolic resin binder is present in the binder material in an amount of 1 t in 20%, based on the weight of the non-aqueous phenolic resin-20 pixel.

Material according to claim 1, characterized in that the oil-soluble phenolic resin which is reacted with the drying oil is a condensate of a phenol of the general formula 25 OH »30 c in which A, B and C are each a hydrogen atom, a halogen atom, a hydrocarbon or hydrocarbon group, and an aldehyde of the general formula RCHO in which R is a hydrogen atom or a hydrocarbon group of 1-8 carbon atoms.

Material according to claim 2, characterized in that the oil-soluble phenolic resin which is pre-reacted with the drying oil is a novolac or resole resin.

A material according to any one of claims 1-3, characterized in that the non-aqueous phenolic resin component of the binder material is a polybenzyl ether resin.

A material according to any one of claims 1-4, characterized in that the drying oil component comprising the drying oil and the pre-reacted, oil-soluble phenolic resin is present in the binder material in an amount of 1-10%, calculated on the weight of the non-aqueous phenolic resin.

A material according to any one of claims 1-5, characterized in that the drying oil is one or more of the oils castor oil, heavy oil, flaxseed oil, safflower oil, essential oil and soybean oil.

Material according to claim 6, characterized in that the drying oil comprises a mixture of castor oil 20 and heavy oil in a weight ratio of 3: 1 to 4: 1.

Material according to any one of claims 1-7, characterized in that it further contains mineral turpentine as a diluent.

A curable molding composition, characterized in that it contains a major amount of an inorganic aggregate and an effective binding amount of up to 40% by weight of a binder material according to any one of claims 1-8.

Process for making a molded molding product, characterized in that a molding mixture according to claim 9 is formed and contacting the molded mixture with a curing agent for the binder.

Process according to claim 10, characterized in that the shaped mixture is cured by passing a gaseous curing agent through it.

Process according to claim 11, characterized in that the curing agent is a tertiary amine. DK 168366 B1

Additive material for phenolic resin-polyisocyanate binder systems for foundry mixtures, characterized in that it comprises a drying oil which has been crosslinked to a viscosity (25 ° C) in the range of E 5 to M on the Gardner Hold bubble viscometer scale by reaction with from 10 to 30% by weight of an oil-soluble phenolic resin, based on the total weight of the additive material, to form direct bonds between the drying oil and the oil-soluble resin.

Material according to claim 13, characterized in that the phenolic resin is as claimed in claim 2 or 3.

Material according to claim 13 or 14, characterized in that the drying oil is as defined in claim 6 or 7.

Material according to any one of claims 13-15, characterized in that it further contains mineral turpentine as a diluent. 20 25 30 35