SE422807B - Cast binder composition - Google Patents

Abstract

Cast binder comprising a fulvene with the formula <IMAGE> where each of R1 and R2 is independently a hydrogen atom or a hydrocarbon group with 1-10 carbon atoms, or else a furyl group; alternatively, R1 and R2 are joined together and - together with the carbon atom to which they are bound - form a cycloaliphatic hydrocarbon group; and where each of R3, R4, R5 and R6 is independently a hydrogen atom or a methyl group, but at most only one of the groups R3, R4, R5 and R6 is a methyl group; prepolymer prepared from such fulvenes; as well as mixtures thereof; also an acid catalyst with a pKa value of about 7 or less.

Description

8004361-5 that the metal has solidified, can be easily broken down for shaking or removal from the casting part. Consequently, it must be considered very difficult to obtain new adhesives for casting applications, which adhesives exhibit the required properties. The problem becomes even more acute when the aim is to produce a relatively cheap binder.

The present invention relates to a casting composition which comprises a major amount of casting ballast material and an effective bonding amount up to about 10% by weight, based on the weight of the ballast material, of a binder composition comprising a fulven and / or prepolymer thereof. The fulvenes used are represented by the formula: R 1 / C 1 / B 2 / ° \ ïóïaeíïï fi 5 4 Each of the groups R 1 and H 2 is each hydrogen or a hydrocarbon containing 1-10 carbon atoms or a furyl group, or these groups are also joined together to form a cycloaliphatic hydrocarbon group together with the carbon atom to which they are attached. Each of the groups H3, R4, R5 and R6 is each hydrogen or methyl, provided that at most only one such group R3, R4, R5 or H6 is methyl. The binder composition also contains an acid catalyst with a pKa value of about 7 or less. The acid catalyst is incorporated into the composition prior to molding or is accomplished by passing a gas through the molded composition.

It should be noted that, if an excess of aldehyde or ketone used; in the preparation of the fulven, RÄ or R5 may have the structure ¿_FL10H. In such a case, H3 and H6 have previously given meanings.

The fulvenes used according to the present invention are thus represented by the formula: Bé \\, / Bl É // R6 "" 'W fi' "" R3 R5 - * - C '- C * -Ra 10 15 20 25 BO 35 Each of the groups H1 and H2 is each hydrogen or a hydrocarbon containing 1-10 carbon atoms or a furyl group, or they are bonded to each other, together with the carbon atom, to The hydrocarbon groups are preferably free of non-benzene unsaturation and include alkyl groups such as methyl, ethyl, propyl and butyl; aryl groups such as phenyl and naphthyl; alkaryl groups such as benzyl; aralkyl group; and cycloalkyl group such as cyclopentyl. on some cycloaliphatic rings are cyclopentyl and cyclohexyl and cycloheptyl.

The groups H3, H4, H5 and H6 are each hydrogen or methyl, with the proviso that at most only one group H, H4, H5 or H6 is methyl. Mixtures of the fulvenes can be used, if desired. In addition, instead of or in combination with the fulvens, prepolymers of the above fulvens can be used which still contain sufficient unsaturation (eg at least about 10%) for subsequent curing to achieve the required strength properties of the mold body and are still sufficiently liquid to , when applied either as such or in admixture with diluents, float or flow to coat the aggregate material. Mixtures of fulven prepolymers can also be used. Again, it should be noted that if an excess of aldehyde or ketone was used in the preparation of the fuel, 114 or H5 may have the structure _íj_ on.

In such a case, H3 and H6 have previously been indicated.

Examples of such fulvenes are dimethylfulven (H1 and H2 are methyl; and H3, H4, H5 and H6 are H); methylphenylfulven (H1 is phenyl; H2 is methyl; H3, H4, H5 and H6 are H); the cyclohexyl fulvenes (H1 and H2 are linked and form a cyclohexyl ring with the common carbon atom to which they are attached; H3, H4, H5 and H6 are H); methyl isobutylfulven (H1 is methyl, H2 is isobutyl; H3, H4, H5 and H6 are H); methyl ethyl fulven (H 1 is methyl, H 2 is ethyl; H 3, H 4, H 5 and H 6 is H); diphenylfulven (H1 and H2 are phenyl; H3, H4, H5 and H6 are H); and the furyl fulven (H1 is furyl, H2 is H; and H3, H4, H5 and H6 are H).

Fulvenes have been known for many years, which also applies to their production methods. Furthermore, it is known that fulvenes are polymerized in the presence of acids. The fulvens of the present invention can be prepared by reacting a carbonyl compound (eg ketones and aldehydes) with the cyclopentadiene and / or methylcyclopentadiene in the presence of a basic catalyst. such as a strong base (eg KOH), an amine and basic ion exchange resins. Examples of methods for preparing fulvenes are found in U.S. Patent Nos. 2,589,969, 5,051,765 and 5,192,275. Examples of methods for preparing fulvenous polymers are found in U.S. Patent Nos. 2,512,698, 2,587,791, 2,898. 525 and 5 590 156.

In addition, the composition of the present invention contains an acid catalyst. The acid catalysts used have a pKa value of 7 or less and include the inorganic mineral acids such as phosphoric acid, sulfuric acid and hydrochloric acid, as well as such organic acids as formic acid, oxalic acid and the organically substituted sulfonic acids such as benzenesulfonic acid and toluenesulfonic acid. The acid catalyst can be provided in the casting mixture before molding (ie the "no bake" process) and / or by passing a gas through the molded composition, such as an acid itself or a gas, such as SO CO2, which together with a component of the shaped composition (eg a peroxide) forms an acid in situ.

When the acid is present in the mixture even before formulation, it is usually present in amounts up to a maximum of about 30% by weight based on the amount of binder used. When using a "cold box" process, a gassing time of up to about 5 seconds is usually sufficient.

The fulvenes and / or polymers thereof can be used in combination with casting binder systems based on furfuryl alcohol and / or furan prepolymers. The furan prepolymer includes reaction products of furfuryl alcohol and of aldehydes, such as formaldehyde. In addition, the aldehyde-furfuryl alcohol reaction product can be modified with varying amounts of reactants, such as urea.

The molar ratios of formaldehyde to furfuryl used can vary considerably. For example, the furan polymer may be prepared from from about 0.4 to about 4 moles of furfuryl alcohol per mole of formaldehyde and preferably from about 0.5 to about 2 moles of furfuryl alcohol per mole of formaldehyde.

The furan polymer which can be used according to the present invention can be any of the various furan polymers which are known to be suitable for molding and especially for casting purposes. Examples of such furan polymers are those obtained from about 1 mole of urea, about 0.2 to 2 moles of furfuryl alcohol and about 1 to 5 moles of formaldehyde, as described in U.S. Patent Nos. 5,222,515. and 5,247,556. Other suitable furan polymers are described in U.S. Patent No. 5,546,554.

The furan polymers are usually prepared by polymerization in the presence of an acid catalyst. Usually, when a furan polymer is used, it is added together with furfuryl alcohol.

When the fulvenes are used in admixture with furfuryl alcohol and / or furan polymers, they are generally used in amounts of from 20 to 80% by weight of the mixture of the fulvenes with furfuryl alcohol and / or furan polymers. The mixtures should have viscosities that make them suitable for floating or flowing on the aggregate material, and they should also be homogeneous.

When producing a casting structure, the useful aggregate material is one commonly used in the manufacture of casting structures or molds, and in particular the aggregate material is made of sand. When producing an ordinary sand-type mold, the ballast material used has a sufficiently large particle size to provide sufficient porosity in the mold to allow volatile substances to escape from the mold during the casting operation. As used herein, the term "ordinary sand-type molds" refers to molds having sufficient porosity to allow volatiles to escape therefrom during the casting operation.

Typically, at least about 80% by weight, and preferably about 90% by weight of the aggregate material used before moldings has an average particle size of not less than about 150 mesh (Tyler scale). The ballast material for molds preferably has an average particle size between about 50 and about 150 mesh (Tyler scale). The preferred aggregate material for use with conventional molds is silica, wherein at least about 70% by weight and preferably at least about 85% by weight of the sand is silica. Other suitable ballast materials include zirconium, aluminosilicate sand, chromite sand and the like. Although the aggregate material used is preferably dry, it may contain small amounts of moisture, such as up to about 0.5% by weight or even higher, based on the weight of the aggregate material. In ordinary sand-type casting applications, the amount of binder is usually not greater than about 10% by weight, with it preferably ranging from about 0.5 to about 7% by weight based on the weight of the aggregate material. The binder content usually ranges from about 1 to about 5% by weight, based on the weight of the ballast material in ordinary sand-type castings.

When the binder systems of the present invention were used to make ordinary sand-type moldings, the following steps were used. A casting mixture is prepared, which contains a ballast material (eg sand) and the binder; 2. The casting mixture is introduced into a mold or imparted a certain pattern to achieve the desired configuration; The shaped body is allowed to achieve a minimum strength in the mold; and g 4. The shaped body is then removed from the mold or pattern so as to allow it to cure further, thereby obtaining a hard, solid, cured mold body.

The casting mixture may optionally contain other constituents, such as iron oxide, ground or finely divided flax fibers, wood pitch, refractory flour and the like.

A particularly valuable additive for the polymer composition of the present invention is a silane of the general formula: R 10, R 10, B 3 / wherein R 'is a hydrocarbon radical and preferably an alkyl radical of 1-6 carbon atoms and R is an alkyl radical and an alkoxy-substituted alkyl radical or an alkylamino-substituted alkyl radical, wherein the alkyl groups have from about 1 to 6 carbon atoms. The above-mentioned silane is usually used in concentrations of from 0.1 to about 2% by weight based on the binder and improves the adhesion to the cast ballast particles.

Examples of some suitable silanes are gamma-aminopropyltriethoxysilane [NH2 (CH2) 5Si (OC2H5)] and trimethoxysilylpropethyleniamine [NH2cH2cH2NH (cH2) 3si (ocH5) 3.

Methods for distributing the polymer on the aggregate material are well known to those skilled in the art.

In order that the present invention may be better understood, the following non-limiting examples of moldings are given. Total cereals, 10 15 20 25 50 35 40 8004361-5 7 parts refer to parts by weight, unless otherwise stated.

The following Examples A-G represent some typical representations of fulvenes.

Example A Preparation of methyl isobutyl fulven About 2.5 moles of cyclopentadiene and about 2.5 moles of methyl isobutyl ketone are reacted in the presence of a sodium ethoxide catalyst. The reaction is carried out at a temperature of about 25-2500 for about 5 l / 2 hours.

The yield is about 60%, and the product is distilled according to the method described by Kice, JACS 80, 5796 (1958). The fraction boiling at 92-9400 has an nD25 of 1.5210 and is according to gas chromatography analysis 97% methyl isobutyl fulven.

Example B Preparation of methyl ethyl fulvenes About 5 moles of cyclopentadiene and about 5 moles of methyl ethyl ketone are reacted in the presence of an ion exchange resin catalyst. The reaction is carried out at about 14-4100 for about 5 hours followed by another 16 hours at about room temperature. The yield is about 42%, and the product is distilled according to the method described by McCain in J. Chem. soc., 23, 682 (1958). The fraction boiling at 67-6900 has an nD25 of 1,555 ° and is according to gas chromatography analysis 91.0% fulven, 5.6% dicyclopentadiene and 5.4% unknown substance.

Example C Methylphenyl fulven In a two-liter three-necked flask is charged isopropyl alcohol (1000 ml), methanol (500 ml) and sodium (10 g). Freshly distilled cyclopentadiene (180 g) and acetophenone (261 g) are mixed and slowly added with stirring to the solution in the flask. The reaction is allowed to proceed at room temperature. After 1 1/2 hours, the addition is complete. The reaction mixture is mixed with water, and the organic layer is extracted into hexane. The hexane extract is washed with water and evaporated. The crude methylphenyl fulvenene is distilled (80-85 ° C / 0.1 mm), and the distillate is a ruby red liquid.

Example D Pentamethylene fulven In a flask containing isopropyl alcohol (500 ml) and 25% sodium methylate solution (10 g), a mixture of cyclopentadiene (150 g) and cyclohexanone (200 g) is charged over a period of 2 hours. When the addition is complete, mixing is carried out with water, and the organic layer is extracted into hexane.

Example E Diphenylfulven Approximately equimolar amounts of benzophenone and cyclopentadiene are reacted in an ethanol / sodium ethoxide solution according to the method described by Kice, in JACS 80, 3796 (1958). The resulting dark red crystals are recrystallized from ethanol and dried under vacuum.

Example F Furylfulven Approximately equimolar amounts of furfural and cyclopentadiene are reacted in the presence of diethylamine catalyst and about 53% methanol solvent according to the method described by C. Schmidt, in Chem. Ber., Volume 90, pages 1352, 1957. A viscous dark material is separated from the water layer.

Example G Dimethylfulven Approximately equimolar amounts of acetone and cyclopentadiene are reacted in the presence of an amine catalyst according to the method described by Freiesleben in Chem. Ab., Vblym 59, 99l4A, 1965. The product is separated from the aqueous layer and vacuum distilled.

Examples 1-8 Casting sand mixtures are prepared by mixing sand with the binder compositions shown in the Table below. The resulting cast sand mixtures are then formed into standardized AFS tensile strength tests using standard procedures. The cured samples are tested for tensile strength and hardness. The polymer used is a furan polymer obtained by reacting about 57.27 parts by weight of furfuryl alcohol, about 51.45 parts by weight of urea-formaldehyde concentrate with approximately equimolar amounts of urea and formaldehyde, about 0.20 parts by weight of H 3 PO 3 and about 0.10 parts by weight of KOH. The acid catalyst used is toluenesulfonic acid. The silane is gamma-aminopropyltriethoxysilane.

About 5,000 parts by weight of the sand are mixed with about 15.5 parts by weight of the acid catalyst and about 45 parts by weight of the furan polymer, fulven, furfuryl alcohol and silane packaging. The table gives tensile strength values in kg / cm2 as well as hardness values. 8004361-5 .NU-WW .NPWNG WQ. mmvm fl u fi w hmuummuho% fl m flfl wßdß pwnmüksm ww m.:H: N o.mm zm m. @ ßw m.:m> fl umHwn & ooH øH> .ë fi u fi + .E fi u rm mm 075 i odm: m må m »mm: .ES: N wm wm mw w.mm Hm Hm MN fi.> M .saw 4 mm mo ~ mw m.mH ms ow ow: .mn .E fl u m vw: .u fifl ms »ms .w flfi ms ams .u flfl m fl» mn .u fifl m fl: name nwmm fl: name ummäv nunms nwmnu: name nmmnu Aim mïb .ïëß .HQÉ š fl wwn fi wwwwmmwm æmïo æmïo mmïo mmïc aß fl w Gm> H§mQmHævmE Qm> H fi m | m @ cmmoH zo hH> h Ro: & oà .Hwëh fi omnmhäm um ma um mr um ma nw ms w mñ fl w m fifi w m.mH w m fifi .Hopmmm fi mpmxwnæw .w ooom m ooom m ooom m ooom cQmm | oHom nonwwz amm HH flfi wnm fi u 8004361 w 10 8004361-5. : oo m.> mo: qo om m.>:>: oo: @ »ooo fi o:> o .s fl o H + s fi o: w oo mä: ß mæ o:: d oo: JN .ES: N: ß m . :: M »no nu nw mm: .oN .s fl p: mo m.æ: o: .m oß _:.» mm m.:H s fi p m_ »wo .o flfl ms» ms .o flfl os own .o fifl mn »ms .o :: ms | U fi m fl uwmäo | onm fl. | mm fi o: name nwm fi ø nomm fl | wmnU o fi oonwow \ NH \\ @ \ W. fi \ \ ® \ Ü fi PWWHHHGD®Q..H.NÜm & m: .o §m: .o & m: .o @m: .o so fifi w fi m> fl dm fl m> fl5 m Qm> H§uHhnSm Gw> H5wHhm5m ø fl hunmn fl huww oom won hwum oom ow a Rom Ro: xon oo: Hosox fl ß fi äosonøm å: å: ä: å: Qwëæ fl oanmnßw um mä um mä um ma um mn m m.mH wm «nH w mqm fl w m.MH nouwmæ fl mpmxm fi æm w ooom m ooon w ooon w ooon onßm | o: om nonowz wwmm .mu fi om H H fl wndü 8004361-5 ll While the tensile strength values of the binders, where the fulvenes replace varying amounts of the furfuryl alcohol, are lower than the corresponding values without the fulvenes, the use of the fulvens also gives satisfactory results for the casting binder is much cheaper than the use of the larger amounts of furfuryl alcohol.

Examples and Casting Sand Mixtures are prepared by mixing Wedron 5010 sand (2000 g) with 24 g of a binder composition containing 40% by weight of the furan polymer of the type used in Examples 1-8; about 0.15% of the silane used in Example 1-8; and varying amounts of furfuryl alcohol (FA) and fulven are shown in the Table below; and with 16 g of methyl ethyl ketone peroxide. The resulting sand mixtures are then formed into standardized AFS tensile strength tests using the standard procedure. The samples are cured by gassing with SO 2 for 5 seconds, unless otherwise stated, and then blown through with air for 10 seconds, unless otherwise stated. The cured samples are tested for tensile strength.

Table II% FA Dra na11f. kg / omg% Fulven Immediately 1 hour. 24 tim. 60% FA 8.1 13.1 14.0 40% FA 20% dimethyl- 7 ,? 15.7 19.5 fulven

Claims (13)

1. åsoo4ss1-s 12 PATENT CLAIMS l. Casting composition, characterized in that it comprises: a. A major amount of casting ballast material; and eb. an effective binding amount up to about 10% by weight, based on the weight of the aggregate material, of a binder composition comprising a fulven of the formula: R 2, C 1/2 H 1 H C C 1 - C 4 wherein each of B 1 and R 2 is each hydrogen or a hydrocarbon containing 1-10 carbon atoms or a furyl group; or wherein B1 and R2 are linked and together with the carbon atom to which they are attached form a cycloaliphatic hydrocarbon group; and wherein each of R 3, H 4, R and R 6 is each hydrogen or methyl, with the proviso that at most only such a group H 5, R 4, R 5 or R 6 is methyl; prepolymers of these fulvenes; and mixtures thereof; and an acid catalyst with a pKa value of about 7 or less. 2. A composition according to claim 1, characterized in that the acid is formed in situ. Composition according to Claim 1 or 2, characterized in that the binder also contains furfuryl alcohol. Composition according to any one of the preceding claims, characterized in that the binae medium also contains furfuryl alcohol and a furan polymer. Composition according to any one of the preceding claims, characterized in that it also contains a silane. g Composition according to one of Claims 1 to 5, characterized in that the fulven is dimethylfulven. Composition according to any one of claims 1-5, characterized in that the fulven is methylphenylfulven. 8004361-5 Sat. Composition according to any one of Claims 1 to 5, characterized in that the fulven is methylisobutylfulven. 9. A composition according to any one of claims 1-5, characterized in that the fulven is cyclopentamethylene fulven. 10. lO. Composition according to any one of claims 1-5, characterized in that the fulven is methylheptylfulven. 11. ll. Composition according to any one of claims 1 to 5, characterized in that the fulven is furyl. 12. A composition according to any one of claims 1-5, characterized in that the fulven is methylethylfulven, g 7 Composition according to any one of the preceding claims, characterized in that the fulven component is a reaction product of a carbonyl compound and said compound of the formula: wherein R 1 -R 6 have the meanings given in claim 1, and with the further proviso that, if the parent ratio of carbonyl to said compound is greater than 1, Ru or R 5 is E 1 OH Re 8004361-5 SUMMARY Casting binder containing a fulven of the formula: R2 \ C / R1 HC / \: ß: i ve 5 C H4 wherein var and one of R 1 and R 2 separately is hydrogen or a hydrocarbon containing 1-10 carbon atoms or a furyl group; or wherein B1 and R2 are linked and together with the carbon atom to which they are attached form a cycloaliphatic hydrocarbon group; and wherein each of R 3, R 4, R 5 and R 6 is each hydrogen or methyl, with the proviso that at most only one such group R, H 4, R 5 or R 6 is methyl; prepolymers of these fulvenes; and mixtures thereof; and an acid catalyst with a pKa value of about 7 or less.