KR20120081070A - A foundry binder comprising one or more cycloalkanes as a solvent - Google Patents

Abstract

(a) a polyol component selected from the group consisting of phenolic resins, polyether polyols, polyester polyols, aminopolyols, and mixtures thereof, and (b) polyisocyanate components, wherein components (a) and / or (b) ) Discloses a cast binder further comprising at least one cycloalkane as a solvent.

Description

A casting binder comprising at least one cycloalkane as a solvent.

Related application

This application claims the priority of US Provisional Patent Application 61 / 266,036, filed July 16, 2009.

In the casting industry, one of the processes used to make metal parts is "sand casting." In sand casting, disposable casting forms, such as molds, cores, sleeves, pouring cups, coverings, etc., are refractories (generally sand) and organic or Prepared by a foundry mix comprising a mixture of inorganic binders.

Casting shapes are typically produced by so-called no-bake processes, cold-box processes and / or heat cured processes. In this non-baking process, the liquid curing catalyst is mixed with the refractory and binder before forming the mixture in a mold to form a casting mixture. The foundry sand mix is shaped by allowing it to compress in a mold and to harden until self-supporting. In the cold box process, the vapor phase curing catalyst passes through a shaped mixture of aggregate and binder (typically in a corebox) to form a cured casting shape. In the thermosetting process, a shape mixture is exposed to heat activating the curing catalyst to form a cured casting shape.

There are many requirements for the binder system to work effectively. For example, the binder should typically have a low viscosity, be free of gel, and remain stable under storage and use conditions. In order to increase productivity in the manufacture of casting shapes, the binders need to be cured effectively, so that the casting shapes must be self-supporting and handleable as soon as possible.

For non-baking and thermosetting processes, there must be adequate working time to be able to produce larger cores and molds. On the other hand, for cold box processes, the molded casting mixture must cure almost immediately upon contact with the vapor phase cure catalyst. Casting shapes made from the casting mixture using non-baking, coldbox or thermoset binders have adequate mechanical strength, in particular instant tensile and transverse strength, scratch hardness , Resistant to ambient humidity.

One of the biggest challenges facing manufacturers is that they can be handled and stored after the casting shape is made and can also be held together so that they do not break down prematurely during the metal casting process, but often referred to as shake-out. It is to make a binder, which can tolerate acceptable mold and core removal properties by cooling of the solidified cast metal part. Without this feature, time-consuming and labor-intensive means must be applied to crush the used casting shapes, thereby allowing the metal part to be removed from the casting mold and core assembly. Another associative property required for an effective cast binder is that the cast shape made of the binder must be easily released from the mold that produces the shape.

The flowability of the casting mixture made from the refractory and organic binder can pose greater problems with regard to cold box applications. This is because in some cases the components of the binder, in particular the components of the phenolic urethane binder, can be reacted prematurely while waiting for them to be used after mixing with refractory sand. If this premature reaction occurs, it may reduce the fluidity of the casting mixture and the mold and core made of the binder will have reduced mechanical strength. This reduction in flowability and decrease in strength over time indicates that the "benchlife" of the casting mixture is not appropriate. If the binder results in a casting mixture that does not provide adequate life, the binder is of limited commercial value.

In view of all of the above requirements for commercially successful casting mixtures, the rate of development of casting binder technology is gradual. It is not easy to develop a binder that can meet all of the requirements of interest in a cost effective manner.

Moreover, in addition to good performance and cost economy, there may be demands on the composition of the formulation due to environmental, health and stability regulations and concerns. Environmental concerns are particularly relevant because most cast binders commercially used today contain significant amounts of aromatic hydrocarbon solvents, which in turn are benzene, toluene, xylene, 1,2,4-trimethylbenzene, naphthalene And fractions of concern with compounds such as other aromatic compounds. Recently, there is an increasing concern about the use of aromatic hydrocarbon solvents in cast binders, and there is a widespread interest in reducing the amount of use or totally excluding them.

The prior art describes several attempts to reduce and possibly eliminate aromatic hydrocarbon solvents in cast binder systems based on phenolic resole resins and polyisocyanates. For example, EP 0771569 describes the replacement of aromatic hydrocarbon solvents with methyl esters of one or more fatty acids having a carbon chain of 12 carbon atoms. Although the binders make useful cores and molds, it has been found that they produce smoke and mace odors during the pouring, cooling and shakeout processes, recovering the sand obtained from the used molds and cores made of the binders. It has been found to be more difficult to reclaim and reuse. Thus, in practice, there is a tendency to use fatty acid esters as co-solvents in combination with traditional aromatic hydrocarbon solvents.

More recently European Patent 1057554 describes the use of alkylsilicates, in particular tetraethylsilicate, in place of aromatic hydrocarbon solvents. This technique also has several drawbacks, which are acidic used to reduce the amine curing gas and the formation of fine white silica particles that can, for example, be deposited on cast parts, accumulate in the sand used or float in the air. Gel formation in a scrubber solution.

Small amounts of additives in polycyclic polyisocyanate binders, in particular phenolic urethane cold-boxes and non-plastic binders, such as acyclic aliphatic solvents such as kerosene and tetratradecene Although their strong non-polar solvency properties are used in combination with the amount in the binder formulation, the combination of the total binder, namely Part 1 (polyol component) and Part 2 (polyisocyanate component) Results were significantly limited to less than 5% by weight in weight.

In view of this background, there is a need to develop casting binders that do not contain aromatic hydrocarbon solvents or use them at much reduced levels while maintaining good performance and cost effectiveness and due consideration for environmental, health and safety concerns. There is.

SUMMARY OF THE INVENTION

The present invention provides a polyol component selected from the group consisting of (a) phenolic resins, polyether polyols, polyester polyols, aminopolyols and mixtures thereof, and ( b) a polyisocyanate component, wherein component (a) and / or (b) further relates to a cast binder, further comprising at least one cycloalkane as a solvent. The present invention also provides a casting mixture made of the casting binder, a cold-box for producing a casting shape using the casting mixture, non-baking and thermosetting processes, and a casting metal part using the casting shape. It relates to processes for manufacturing and processes for casting metal.

When formulating the cast binders, the present invention can remove or reduce aromatic hydrocarbon solvents including benzene, toluene, xylene, 1,2,4-trimethylbenzene, naphthalene and other aromatic compounds and fractions. The use of the binders in accordance with the environmental, health and safety benefits can be obtained. As a result, undesired gases, vapors and odors are reduced or eliminated when casting shapes are made from a casting mixture made of a binder according to the invention and when metal parts are cast using these casting shapes. Moreover, there are no potential exposures to the silica particles present when alkylsilicate is used as the solvent in the casting binder used to make the casting shapes.

As a whole or in part of the aromatic hydrocarbon solvent, in general, the use of cycloalkane as a solvent in a limited cast binder can have (1) a detrimental effect on the ozone layer, where the cast shape is made of binders and the cast shape is metallic Reduce the amount of photochemically active species released when used to make metal parts in the course of a casting process; (2) reduce the formation of tar-like material in the vent system of a semi-permanent mold, a technique commonly used to make cylinder heads of automobiles; (3) provide improved quality of cast metal parts made from cast shapes; (4) improve the quality of molds and cores by removing or reducing solvents that accumulate in the consumption of recovered sand and green sand molding systems; And (5) it is believed that it is possible to reduce the formation of dense smoke during injection, cooling and shakeout.

Since binders based on polyols and polyisocyanates, in particular phenolic resol resins, are known to be sensitive to the various properties of the solvent, without adversely affecting the product's storage stability and the performance properties of the binder related to the core and mold manufacturing performance It is an unexpected discovery that cycloalkanes can be used, in whole or in part, by replacing the aromatic hydrocarbon solvents conventionally used in such binders. This is especially true because acyclic aliphatic solvents such as kerosene and tetradecene are known to be incompatible with phenolic resins and polyisocyanates at high levels, especially at levels capable of completely replacing all aromatic hydrocarbon solvents in the cast binder. This is an unexpected discovery.

DETAILED DESCRIPTION OF THE INVENTION

Preference is given to using the binder system in a two-part system.

The polyol component (part 1) of the cast binder comprises a polyol selected from the group consisting of phenolic resins, polyether polyols, polyester polyols, amine polyols and mixtures thereof. Preferred as polyols are phenolic resol resins.

The polyisocyanate component (part 2) of the binder comprises a polyisocyanate selected from the group consisting of aliphatic polyisocyanates and aromatic polyisocyanates and mixtures thereof. Preferred as the polyisocyanate is methylene diphenylisocyanate because of its availability.

As mentioned above, the preferred polyol is a phenolic resin, which is liquid or organic solvent-soluble. The phenolic resin component of the binder composition is generally used as a solution in an organic solvent. The amount of solvent used should be sufficient to produce a binder composition having a suitable viscosity that allows uniform reaction with the polyisocyanate component in its uniform coating and cast sand mixture on aggregate. The specific solvent concentration for the phenolic resin can vary depending on the type of phenolic resin used and its molecular weight. In general, the solvent concentration may be in the range of up to 80% by weight of the polyol component, generally in the range of 20 to 80% by weight of the polyol component.

Phenolic resol resins are preferably prepared by reacting a molar excess of aldehyde with phenol in the presence of an alkali catalyst or a metal catalyst. Preferably, the phenolic resins are substantially free of water and are organic solvent soluble. Preferred phenolic resins for use in the binder compositions of interest are known in the art and are described in particular in US Pat. No. 3,485,797, which is incorporated herein by reference. These resins, known as benzyl ether phenolic resol resins, are reactants of aldehydes and phenols. These predominantly comprise crosslinks connecting the phenolic nuclei of the polymer, which are ortho-ortho benzylic ether bridges. In the presence of divalent metal ions such as metal ion catalysts, preferably zinc, lead, manganese, copper, tin, magnesium, cobalt, calcium and barium, aldehydes and phenols can be employed in a molar ratio of aldehyde to phenol of at least 1: 1. It is made by making it react.

The phenols used to prepare the phenolic resol resins have been used so far for the formation of phenol itself and / or phenolic resins and are also unsubstituted among two ortho-positions or one ortho- and para-positions. One or more phenols are included. These unsubstituted positions are required for the polymerization reaction. Any one or all of the remaining carbon atoms of the phenol ring may be substituted or none may be substituted. The nature of the substituents can vary widely and it is only necessary that the substituents do not interfere with the polymerization of phenols and aldehydes at the ortho- and / or para-positions. Substituted phenols used in the preparation of phenolic resins include alkyl-substituted phenols, aryl-substituted phenols, cycloalkyl-substituted phenols, aryloxy-substituted phenols and halogen-substituted phenols, the substituents being from 1 to 26 It includes carbon atoms, preferably 1 to 12 carbon atoms.

Alternatively, novolak resins can be used. Bisphenol F is the simplest novolac and is prepared by reacting a large molar excess of phenol with formaldehyde under acidic conditions, which yields the o, p 'isomer, p, p' isomer and o, o 'isomer. To produce an isomeric mixture comprising. Typical acidic catalyst is oxalic acid.

Specific examples of suitable phenols include phenol, o-cresol, p-cresol, 3,5-xylenol, 3,4-xylenol, 2,3,4-trimethylphenol, 3-ethylphenol, 3, 5-diethylphenol, p-butylphenol, 3,5-dibutylphenol, p-amylphenol, p-cyclohexylphenol, p-octylphenol, 3,5-dicyclohexylphenol, p-phenylphenol, p -Crotylphenol, 3,5-dimethoxyphenol, 3,4,5-trimethoxyphenol, p-ethoxyphenol, p-butoxyphenol, 3-methyl-4-methoxyphenol and p-phenoxy Phenols are included. Also suitable are polycyclic phenols such as 4,4'-diphenol and bisphenol A.

The aldehyde used to react with the phenol has the formula RCHO, where R is hydrogen or a hydrocarbon radical having 1 to 8 carbon atoms. Aldehydes that react with phenols can include any aldehydes that have been used so far in the manufacture of phenolic resins such as formaldehyde, acetaldehyde, propionaldehyde, furfuraldehyde, benzaldehyde, and mixtures thereof. Most preferred aldehyde is formaldehyde.

Polyether polyols are commercially available and methods for their preparation and methods for determining their hydroxyl values are well known. The polyether polyols are prepared by reacting an alkylene oxide with a polyhydric alcohol in the presence of a suitable catalyst, such as sodium methoxide, according to methods well known in the art. Any suitable alkylene oxide or mixture of alkylene oxides can be reacted with polyhydric alcohols to produce polyether polyols. Alkylene oxides used to prepare polyether polyols generally have from 2 to 6 carbon atoms. Representative examples include ethylene oxide, propylene oxide, butylene oxide, amylon oxide, styrene oxide or mixtures thereof. Polyhydric alcohols typically used to prepare polyether polyols have a hydroxy functionality of at least 2.0, preferably 2.5 to 5.0, most preferably 2.5 to 4.5. Examples include ethylene glycol, diethylene glycol, propylene glycol, trimethylolpropane, glycerin and tetramethylol methane.

Aminopolyols are also well known and described in US Pat. No. 4,448,907, which is typically prepared as a reaction product of alkylene oxides and amine compounds. In general, any polyol comprising at least one tertiary amine group is considered to fall within the scope of the definition of “aminopolyol”. The alkylene oxides used to prepare the amine polyols are preferably ethylene oxide and propylene oxide. However, it is also believed that other alkylene oxides may be used as well. Amine compounds that react with alkylene oxides to produce aminopolyols useful in the binder compositions of the present invention include ammonia and monoamino compounds and polyamino compounds having primary or secondary amine groups. Specific examples include aliphatic amines such as primary alkylamines, ethylenediamine, diethylenetriamine and triethylenetetramine, cyclohexylamine, pyrrolidine, morpholine and cycloaliphatic amines such as N, N'-diethylenediamine And aromatic amines such as aniline, ortho-phenylenediamine, meta-phenylenediamine, para-phenylenediamine, aniline-formaldehyde resins and the like. The aminopolyol typically has a hydroxyl number of about 200 to 1000 mg / g KOH, preferably about 600 to 800 mg / g KOH.

Polyesterpolyols that can be used are aliphatic and / or aromatic polyesterpolyols. Preferred polyesterpolyols are mixtures of liquid aromatic polyesterpolyols, which typically have a hydroxide of about 200 to 2,000 mg / g KOH, preferably 200 to 1200 mg / g KOH, most preferably 250 to 800 mg / g KOH Has a siloxane. Has a functionality of at least 2.0, preferably from 2 to 4; It has a viscosity at 25 ° C. of 500 to 50,000 centipoise, preferably 1,000 to 35,000 centipoise, most preferably 1,500 to 25,000 centipoise. Aromatic polyester polyols are typically prepared via transesterification of aromatic esters with alcohols or glycols by acidic catalysts. Phthalates are typically used as aromatic esters for preparing aromatic polyester polyols. Examples of alcohols used to prepare the aromatic polyester polyols include ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,4-butanediol, dipropylene glycol, tripropylene glycol, tetraethylene glycol, Trimethylolpropane, tetramethylolmethane, glycerin and mixtures thereof. Aliphatic polyester polyols are typically prepared by direct condensation of acids with alcohols. Examples of acids used to prepare aliphatic polyester polyols are succinic acid, glutaric acid, adipic acid, citric acid, tetrahydrophthalic acid and mixtures thereof. Examples of alcohols used to prepare the aliphatic polyester polyols include ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,4-butanediol, dipropylene glycol, tripropylene glycol, tetraethylene glycol, Trimethylolpropane, tetramethylolmethane, glycerin and mixtures thereof.

Any organic polyisocyanate can be used in Part 2, ie the polyisocyanate component. The polyisocyanate component of the binder composition is generally used as a solution in an organic solvent, but a binder may be used in which Part 2 consists of 100% polyisocyanate. The concentration of a particular solvent in the polyisocyanate component can vary depending on the type of phenolic resin and its molecular weight used in Part 1 above. Generally, the solvent concentration may be in the range up to 80% by weight, typically up to 50% by weight of the polyisocyanate component.

Examples of organic polyisocyanates used include polyisocyanates having a functionality of at least two, preferably from 2 to 5. It can be aliphatic, cycloaliphatic, aromatic or mixed polyisocyanates or mixtures thereof. Representative examples of polyisocyanates include aliphatic polyisocyanates such as hexamethylene diisocyanate and 1,12-diisocyanatododecane, alicyclic polyisocyanates such as 4,4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate, And aromatic polyisocyanates such as methylenediphenylisocyanate and its isomers and polymeric variants, 2,6-toluene diisocyanate and derivatives thereof. Other examples of suitable organic polyisocyanates are 1,5-naphthalene diisocyanate, triphenylmethanetriisocyanate, xylylene diisocyanate and derivatives thereof and the like. It is also contemplated that chemically modified polyisocyanates, prepolymers of polyisocyanates and quasi-prepolymers of polyisocyanates can be used. Solid or viscous polyisocyanates should be used in the form of an organic solvent solution, which solvent is generally present in the range up to 80% by weight, typically up to 50% of the solution.

The polyisocyanates are used at a concentration sufficient to cause curing of the phenolic resin when catalyzed by tertiary amine curing catalysts. In general, the ratio of isocyanate groups in the polyisocyanate component to hydroxyl groups in the polyol component is from 1.25: 1 to 1: 1.25, preferably about 1: 1.

The part 1 and / or part 2 of the binder comprises at least one cycloalkane as a solvent. The cycloalkane is selected from the group consisting of unsubstituted cycloalkanes, substituted cycloalkanes, and mixtures thereof. Preferably, the number of carbon atoms of the cycloalkane is 5 to 24, and in the cycloalkane of the ring comprising individual fused, bridged, and spiro-connected ring arrangements The number is 1 to 4 and the number of carbon atoms in the individual rings of the bicyclic, tricyclic and tetracyclic cycloalkanes is 3 to 10, preferably 5 to 8 carbon atoms. Examples of cycloalkanes that may be used as solvents in Part 1 and / or Part 2 of the binder include cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, norcaran, norpinan, norbornane, decahydro Azulene, tricycle [2.2.1.0] hexane, tetracyclo [5,2,2,0,0] undecane, spiro [4.5] decane, disspiro [5.1.7.2] heptadecane, decahydronaphthalene, bicyclo Hexyl, tercyclodecane, 1-cyclobutyl-2-cyclopentylethane, perhydroanthracene, perhydrofluorene, their partially unsaturated congeners, alkyl, alkenyl and alkynyl substituents, and their Mixtures include, but are not limited to. Typically, the cycloalkanes that can be used are the decahydronaphthalenes, because of the most readily and abundantly obtainable cycloalkanes.

The cast binder may comprise other solvents. In particular, the cast binder may further comprise one or more solvents selected from the group consisting of aromatic hydrocarbon solvents, dibasic ester solvents, fatty acid ester solvents, and mixtures thereof, which are incorporated into Part 1, Part 2 of the cast binder, Or may be formulated in both Part 1 and Part 2.

The total amount of solvent in the binder is typically 1 to 80 parts by weight based on 100 parts by weight of the binder, preferably 5 to 60 parts by weight based on 100 parts by weight of the binder, and most preferably 15 to 50 parts by weight of the binder. It is within the range of parts by weight.

The total amount of cycloalkane in the binder is typically 5 to 40 parts by weight based on 100 parts by weight of the binder, preferably 5 to 30 parts by weight based on 100 parts by weight of the binder, and most preferably 5 to 5 parts by weight of the binder. It is within the range of 20 weight part.

When the cycloalkane is used in Part 1 of the binder, the total amount of cycloalkane used in Part 1 is from 0 to 30 parts by weight, preferably from 5 to 25 parts by weight based on 100 parts by weight of Part 1 It is within the range of 5 to 20 parts by weight, based on 100 parts by weight of Part 1, most preferably.

When the cycloalkane is used in Part 2 of the binder, the total amount of cycloalkane used in Part 2 is generally from 0 to 60 parts by weight based on 100 parts by weight of Part 2, preferably 5 parts by weight based on 100 parts by weight of Part 2 To 40 parts by weight, most preferably in the range of 5 to 30 parts by weight based on 100 parts by weight of Part 2.

The casting mixture is prepared by mixing foundry refractory with a casting binder. Various forms of refractory and various amounts of binders are used to produce the cast sand mixture by methods known in the art. Normal shapes, shapes of precision casting and refractory shapes can be produced by using the binder system and appropriate refractory materials. The amount of binder used and the types of refractory are known to those skilled in the art. Preferred refractory used to prepare the casting mixture is silica sand, wherein at least about 70%, preferably at least about 85%, by weight of the sand is silica. Other suitable refractory materials for common casting shapes include zircon, olivine, aluminosilicate, chromite, and the like.

In typical casting applications, the amount of binder is generally within the range of about 10% by weight or less, often from about 0.5 to about 7% by weight, based on the weight of the refractory. Often, the content of binder for normal casting shapes is in the range of about 0.6 to about 5 weight percent based on the weight of the refractory.

The binder composition is preferably made obtainable as a two part system having a polyol component in one part (part 1) and a polyisocyanate component as another part (part 2). Generally, the polyol is first mixed with the refractory and then the polyisocyanate component is added, but the order of addition can be reversed. Methods of dispensing a binder onto refractory particles are known to those skilled in the art.

It is well known in the art that other additives such as coupling agents, flow enhancers, benchlife extenders, mold release agents, desiccants, defoamers, wetting agents and the like may be added to the binder, refractory or cast mixture. It will be apparent to those who have it. The choice of specific additives may depend on the specific purposes of the manufacturer.

In general, metal parts have a mold assembly having an internal cavity and a gating system for supplying the cavity with hot liquid metal shaped to match the specifications and profile of the metal part to be cast. Created by creating A mold and / or core is inserted into the mold assembly to form external and internal casting geometries that can shape the metal part as molten metal is poured into the mold assembly and cooled. Optionally, the refractory coating can be applied to all or selected components of the mold assembly into which the liquid metal is in contact.

Casting shapes

(a) introducing a casting mixture into the mold in most amount to form a casting shape;

(b) contacting the casting mixture in the mold with a vapor phase curing catalyst;

(c) allowing the casting shape to harden; And

(d) removing the cast shape from the mold that has become handleable;

It is prepared by a cold box process comprising a.

Curing of the polyol-polyisocyanate binders by the coldbox process is performed by contacting the casting shape with the vapor of volatile tertiary amines, as described in US Pat. No. 3,409,579, which is incorporated herein by reference. Examples of volatile tertiary amines that can be used include trimethylamine, dimethylethylamine, triethylamine, dimethylpropylamine and the like.

Casting shapes

(e) introducing a casting mixture comprising a liquid curing catalyst into the mold in most amount to form a casting shape;

(f) allowing the casting shape to harden; And

(g) removing the cast shape from the mold that has become handleable;

It is prepared by a non-baking process comprising a.

Preferred liquid curing catalysts for the polyol-polyisocyanate binders are tertiary amines and the preferred non-baking curing process is described in US Pat. No. 3,485,797, which is incorporated herein by reference. Specific examples of such liquid curing catalysts generally have a pK _b value in the range of about 5 to about 11, and alkyl groups having 1 to 4 carbon atoms, for example 4-phenylpropylpyridine, isoquinoline, Arylpyridine such as phenylpyridine, pyridine, acridine, 2-methoxypyridine, pyridazine, 3-chloropyridine, quinoline, N-methylimidazole, N-ethylimidazole, N-vinylimidazole, Amines including 4,4′-dipyridine, 1-methylbenzimidazole, 1,4-thiazine and (3-dimethylamino) propylamine.

Casting shapes

(h) introducing a casting mixture comprising refractory, novolac resin and polyisocyanate into the mold heated to the most amount to form a casting shape;

(i) hardening the cast shape; And

(j) removing the cast shape from the mold that has become handleable;

It is manufactured by a thermosetting process comprising a.

The thermosetting process is described in WO 2004050738, which is incorporated herein by reference.

Metal parts

(k) inserting the casting shape into a casting assembly having one or more molds and / or cores;

(l) pouring metal into the casting assembly while in the liquid state;

(m) allowing the metal to cool and solidify; And

(n) separating the cast metal part from the casting assembly;

It is manufactured by a method of casting a metal part comprising a.

The metal parts are gray iron and white iron, ductile iron, ferrous metals such as compacted graphite iron and steel, and aluminum, magnesium And nonferrous metals such as copper, zinc, titanium and alloys thereof. The temperature of the molten iron-containing metal is in the range of about 1100 to about 1700 ° C. The temperature of the molten non-ferrous metal is in the range of about 400 to about 1700 ° C.

The term "comprising" (and grammatical variations thereof) as used herein is used in the sense encompassing "having" or "containing", and is not an exclusive meaning of "consisting of only." . The terms "any" and "the" as used herein are understood to include the plural as well as the singular.

Examples A, B, 1 and 2

Test by coldbox process by first mixing Congleton HST 50 silica sand (WBB minerals, manufactured by Sibelco UK Ltd.) with the binder formulations listed in Table 1 in a Kenwood Chef mixer for 1 minute. Casting cores were made. The phenolic resol resin (RESIN) used in Part 1 of the binder was a polybenzylether phenolic resin prepared with zinc acetate dihydrate as a catalyst according to methods known in the art. The polyisocyanate used in Part 2 of the binder was a poly (methylenediphenylisocyanate having a functionality of 2.7. The same amount of Part 1 and Part 2 was used and the total amount of binder used was 1.2 weight based on the weight of the sand. Was%.

The resulting casting mixture was compressed into a cavity to blow the casting sand mixture into a metal mold that was cured by a cold box process as described in US Pat. No. 3,409,579, having a size of 120 mm x 22.4 mm x 6 mm. Test cores were prepared. The test cores were thus contacted with a mixture of triethylamine (0.25 mL) in nitrogen for 1 second under a pressure of 1.4 bar and then purged with nitrogen for about 18 seconds under a pressure of 4 bar. .

When the binders were made and the test cores were made, no odor was generated.

Unless otherwise indicated, the test cores were made from a freshly prepared cast sand mixture and the lateral strength was measured at 30 seconds, 3 minutes and 6 minutes after the specimen was formed. The measurement of the lateral strength of the test cores makes it possible to predict how the mixture of sand and binder will work in the actual casting operation. Lower lateral strengths for the shapes indicate that the phenolic resin and the polyisocyanate reacted more extensively during and after mixing with the sand and before curing.

Examples A and B are comparative examples and do not contain any cycloalkanes, while Example 1 is within the scope of the present invention.

Table 1 shows the binder formulations and the lateral strengths of the test cores made of the binders.

Example A B One  Part 1 Suzy 64 65 69 DBE ¹ 18 18 AHS ² 34 FAE ³ 15 DHN ⁴ 11  Part 2 MDI 75 75 85 AHS 25 25 DHN 15 Lateral Strength (KPa) ⁵ 30 seconds 1986 1880 1739 3 minutes 2616 2223 2244 6 minutes 3042 2588 2273 ¹ : dibasic ester solvent
² : aromatic hydrocarbon solvent
³ : fatty acid ester solvent
⁴ : decahydronaphthalene
⁵ : kilopascals

The data in Table 1 show that the lateral strength of test cores made from binders containing decahydronaphthalene (DHN) is based on typical aromatic hydrocarbon solvent (AHS) systems and fatty acid esters (FAE) and dibasic ester (DBE) solvents. Over the lateral strength of test cores made from commercially available phenolic urethane coldbox binders.

All documents, patents, and patent applications mentioned in this application are incorporated herein by reference and for any and all purposes as if each individual document, patent or patent application were specifically and individually incorporated by reference. In case of inconsistency the detailed description herein prevails.

The foregoing disclosures herein describe and describe the present invention. In addition, the disclosure only represents and describes preferred embodiments, but as noted above, the disclosure can be used in various other combinations, modifications, and environments and is within the scope of the concept as expressed herein. Changes or variations are possible and fit to the teachings or techniques and / or knowledge of the associated technical field.

The foregoing embodiments also describe the best manners known for carrying out this practice and others skilled in the art may relate the disclosure to the various modifications required by the particular application and use in the or other embodiments. It is intended to be used together. Accordingly, the disclosure is not intended to be limited to the forms described herein. In addition, the appended claims should be construed to include other optional embodiments.

Claims (21)

Foundry binders comprising:
(a) a polyol component selected from the group consisting of phenolic resins, polyether polyols, polyester polyols, amine polyols and mixtures thereof,
(b) a polyisocyanate component,
Wherein the component (a) and / or component (b) further comprises at least one cycloalkane selected from the group consisting of unsubstituted cycloalkanes, substituted cycloalkanes and mixtures thereof as solvent. The method of claim 1,
Cast binder, characterized in that the polyol component comprises a phenolic resol resin. The method of claim 2,
Casting binder, characterized in that 5 to 24 carbon atoms of the cycloalkane. The method of claim 3,
Casting binder, characterized in that 1 to 4 ring number of cycloalkane. The method of claim 3,
Casting binder, characterized in that 4 to 10 carbon atoms in the ring of the cycloalkane. The method of claim 5,
Cast binder, characterized in that at least one cycloalkane has two rings. The method of claim 2,
A cast binder, wherein the cycloalkane is selected from the group consisting of cyclohexane, trimethylcyclohexane, decahydronaphthalene, tetrahydronaphthalene and mixtures thereof. The method of claim 2,
Cast binder, wherein the cycloalkane comprises decahydronaphthalene. The method according to any one of claims 1 to 8,
And (b) component further comprises at least one solvent selected from the group consisting of aromatic hydrocarbon solvents, ester solvents, fatty acid ester solvents and mixtures thereof. 10. The method of claim 9,
Cast binder, characterized in that the amount of cycloalkane in the binder system is 5 to 40 parts by weight based on 100 parts by weight of the binder. The method of claim 10,
Cast binder, characterized in that the amount of the aromatic hydrocarbon solvent is less than 10 parts by weight based on 100 parts by weight of the binder. The method of claim 11,
Cast binder, characterized in that the binder does not comprise an aromatic hydrocarbon solvent. A casting mixture comprising a large amount of refractory and a small amount of the casting binder of claim 9. The method of claim 13,
A casting mixture, further comprising a liquid tertiary amine curing catalyst. A coldbox method for producing a casting shape, comprising the following steps:
(a) injecting a large amount of the composition of claim 9 into a mold to form a cast shape;
(b) contacting the shape with a vapor of a tertiary amine curing catalyst;
(c) curing the shape; And
(d) removing the shape from the mold. A method of casting a metal part, comprising the following steps:
(a) inserting a casting shape made according to claim 15 into a casting assembly having one or more molds and / or cores;
(b) pouring a metal in a liquid state into the casting assembly;
(c) cooling and solidifying the metal; And
(d) separating the cast metal part from the casting assembly. Metal casting produced by the method of claim 16. A non-baking method for producing a casting shape, comprising the following steps:
(a) injecting a large amount of the composition of claim 14 into a mold to form a cast shape;
(b) curing the shape; And
(c) removing the shape from the mold. A method of casting a metal part, comprising the following steps:
(a) inserting a casting shape made according to claim 18 into a casting assembly having one or more molds and / or cores;
(b) pouring a metal in a liquid state into the casting assembly;
(c) cooling and solidifying the metal; And
(d) separating the cast metal part from the casting assembly. Metal casting produced by the method of claim 19. A thermosetting method for producing a casting shape, comprising the following steps:
(a) injecting a mass of a casting mixture comprising (i) a refractory, (ii) a novolak resin and (iii) a polyisocyanate into a heated mold to form a casting shape, wherein the (ii) component and / or ( iii) the component further comprises at least one cycloalkane selected from the group consisting of unsubstituted cycloalkanes, substituted cycloalkanes and mixtures thereof as solvent;
(b) curing the casting shape; And
(c) removing the casting shape from the mold when it becomes handleable.