CN102105242A - Coating compositions for casting moulds and cores for avoiding maculate surfaces - Google Patents

Abstract

The invention relates to a size composition for casting moulds and cores, comprising at least one metallic additive which contains a metal or a compound of a metal, wherein the metal is selected from one of groups 7 or 9 to 12 of the Periodic Table of the Elements. The invention also relates to a process for producing a casting mould, which comprises a mould coating of the size according to the invention, and to the use of said mould for the casting of metals.

Description

Avoid the mold on spot surface and the coating composition of core

The present invention relates to a kind of coating (Schlichte) that is particularly suitable for large-scale casting, and relate to a kind of mold of making the method for foundry goods and containing the mould coating.

For moulding first, most of goods of steel and iron industry and non-ferrous metals industry all will experience casting cycle.With melted material, promptly ferrous metal or non-ferrous metal are transformed into the object that definite geometry is arranged with qualification workpiece characteristic.For making the foundry goods moulding, must at first make the mold of very complicated reception melt sometimes.Mold is divided into discarded pattern that can damage after each casting and the permanent pattern that can produce a large amount of foundry goods separately.

Discarded pattern is made by the fire-resistant granular moulding materials of mineral matter usually, also often is mixed with various other additives in this material, as being the good casting surface of realization (by means of the adhesive sclerosis).Usually the quartz sand of use through washing classification is as fire-resistant granular moulding materials.To satisfying some special applications of special requirement, also can use chromite sand, zircon sand and olivine sand.Use Modeling Material in addition based on fire clay and magnesite, sillimanite or corundum.Making the adhesive of Modeling Material sclerosis can be inorganic or organic natural materials.Less discarded pattern is mainly by making as the Modeling Material of adhesive sclerosis by bentonite, and uses organic polymer as adhesive usually for bigger mold.The manufacturing of mold is carried out usually as follows, and Modeling Material is mixed with adhesive, makes the particle coated with adhesive film of Modeling Material.Then mould material mixture is introduced in the suitable pattern, and optional compacting is so that mold reaches enough stability.Mold is solidified, for example solidify by heating or interpolation catalyst.In case this mold reaches specific at least initial intensity, then can choose wantonly from pattern and take out, and, solidify fully for making it, it is transferred in the kiln, for example to heat the specific time therein to reach specific temperature.

Permanent pattern is used to make a large amount of foundry goods.Therefore it need tolerate casting cycle with relevant load and not impaired.According to application, proved that Special Casting Iron and non-steel alloy and steel alloy also have copper, aluminium, graphite, sintering metal and ceramic material all to be suitable as the material of permanent type mold.Gravity die casting, Hpdc, centrifuge pressure casting and continuous metal cast process are the examples of permanent type mold casting.

In casting cycle, mold stands very high thermic load and high mechanical load.Therefore, can form defective on the contact-making surface between liquid metal and the mold, for example mold cracking or liquid metal infiltrate in the structure of mold.Usually, provide protective coating with the contacted surface of liquid metal, it is also referred to as coating.This coating is made up of the refractory inorganic material and the adhesive that dissolve or be suspended in suitable solvent such as water or the alcohol usually.

Therefore, can carry out modification to the surface of this mold by these coatings, and make it be suitable for the characteristic of pending metal.Thus can be by this coating, by producing the outward appearance that foundry goods is improved on smooth surface, its reason is that coating has compensated by the caused scrambling of the size of Modeling Material particle.In addition, this coating is also influential to foundry goods aspect metallurgical, for example through coating additive on cast(ing) surface is optionally shifted in the foundry goods, these additive improved the surface characteristic of foundry goods.In addition, this coating also be formed on when casting with liquid metal and mold carry out chemical isolation layer.Prevent from thus any adhesion takes place between foundry goods and the mold, thereby can no trouble at all this foundry goods be taken out from mold.In addition, this coating is also guaranteed the heat isolation between mold and the foundry goods.This is even more important to the permanent type mold.If do not satisfy this function, then for example metal mold can stand high to shifting to an earlier date impaired thermic load in follow-up casting cycle.Yet this coating also can be used to the heat transmission between Selective Control liquid metal and the mold, for example to form specific metal structure by cooldown rate.

Usually used coating for example contains clay, quartz, diatomite, christobalite, tridymite, alumina silicate, zirconium silicate, mica, fire clay, also has coke or graphite as raw material.Surface and closed hole that these raw materials cover mold infiltrate in the mold to prevent liquid metal.Because the high isolating power of coating, contain silica or diatomaceous coating as raw material so often use, because this coating can low-costly make, and can take in a large number.

Attempted optionally alloying component to be introduced the surface of foundry goods, for example to improve this surperficial hardness by dope layer.K.Herfurth and S.Pinkert, Technische Zeitschrift f ü r das Gie β ereiwesen, 19,1973,365-400 and K.Herfurth, S.Pinkert, K.Nowak, "

Von Stahlguss in der Gie β form ", Freiberger Forschungsbericht, B 184 1975, and 203-215 has described thickener, and it contains transition metal such as chromium, nickel or the manganese that is siderochrome for example or ferrimanganic form in a large number.The ratio of these metal or alloy is obviously greater than 50 weight % in the thickener.In addition, in thickener, also contain adhesive, normally waterglass.On the mold face that these thickeners are applied to during the casting with liquid metal material (normally steel) contacts.During the casting in the thickener contained metal by the heat fusing of liquid metal material, and with its local alloy that forms on the surface of this foundry goods, this alloy solidifies as the edge shell then.According to the mode of implementing process, can produce the thickness edge shell of 10mm at the most.Therefore, these edge shells can be stone.Be the mold of Production Example such as power shovel, just can no longer need make whole foundry goods by corresponding alloy with the method.On the contrary, only make when the casting just enough selectively by the alloy that can obtain extra high case hardness by means of alloying component contained in this thickener to the tooth of the mold section that is subjected to stress especially such as power shovel.Yet problem in the method is that various materials have different constriction coefficients.Therefore, described do not have identical thickness or irregularity occurs on the surface through consolidated layer, for example crackle, fragment or pit.

When iron and steel casting, on the surface of foundry goods, form defective such as spot surface, rough surface or ablated surface, fragment, plaque, hole or pin hole sometimes or form white or black coating.The reason of this class defective is also not exclusively asked Chu.Once attempted to overcome this defective, for example by changing the casting parameter, the adhesive composition of modification mold or the different additive of interpolation in coating.But the result of these measures is scarcely satisfactory.These defectives disappear when beginning really.Yet it disappears over time, but cannot estimate time, intensity and the size of this defective.

If occur above-mentioned defective really, with regard to needing cast(ing) surface is carried out complicated reprocessing, to reach required surface characteristic.This needs additional processing step, and reduces productivity ratio thus or increase cost.If be difficult for touching or untouchable foundry goods face on defective appears, this also can cause foundry goods discarded.

Therefore, the objective of the invention is to propose can be used for improving in the casting of metals measure of cast(ing) surface, make the surface treatment degree that after casting, can reduce foundry goods.

This purpose is to realize with the coating composition of the feature with claim 1.Favourable expansion according to coating composition of the present invention is listed in the dependent claims.

Find surprisingly, but add the surface quality that specific metallic addition persistence is improved foundry goods that the granulation that for example significantly or fully suppresses on the cast(ing) surface forms to coating composition.Do not find that relatively large metallic addition or its component shift into foundry goods.Therefore, do not appear between foundry goods and the edge shell because the difficult problem that the different coefficients of expansion or constriction coefficient cause.

According to the present invention, the metallic addition that comprises in the coating composition comprises at least a metal or metallic compound, and this metal is selected from a kind of element of the periodic table of elements the 7th family or the 9th～12 family.

The numbering of this family is based on present available IUPAC rule.According to the old rule of IUPAC, the 7th family is corresponding to VIIA family.The 9th and 10 families are corresponding to old the Elements C o of VIIIA family, Rh, Ir and Ni, Pd and Pt, and the 11st and 12 families are corresponding to the IB or the IIB family of old label.

It is zero metal that metallic addition can contain the burning state, and this metal can be that pure state is used or use with the alloy attitude that forms with other metal.But this metallic addition also can be the form of oxide or salt through the metallic forms of oxidation to be existed, as carbonate, nitrate or chloride, wherein preferred oxides.

The preferred metal of going back ortho states that uses is that the state of oxidation is zero metal.

The compound that in metallic addition, can contain multiple above-mentioned metal or these metals.Yet, preferably only have in these metals a kind of with the reduction or oxidation state be contained in the metallic addition.

Preferred metal or its compound that is selected from the 7th, 10 or 11 families in the periodic table of elements that use in metallic addition, wherein preferred especially manganese, nickel and copper.

This metallic addition can only be formed by described metal or its compound.Yet, in metallic addition, except containing these metals or its compound, also can contain other metal or compound.

According to a preferred embodiment, calculate as metal, weight meter based on metallic addition, the metal in this metallic addition or the content of metallic compound are at least 10 weight %, especially be at least 20 weight %, preferred at least 30 weight %, especially preferred at least 40 weight %, more particularly preferred at least 50 weight %.

According to an embodiment, this metallic addition is only by at least a formation, particularly manganese, nickel, copper in the above-mentioned metal.Yet according to an embodiment, this metal and compound thereof the content in metallic addition is just enough less than 90 weight %, according to another embodiment, its content is just enough less than 80 weight %, and according to another embodiment, its content is just enough less than 70 weight %.

Except metallic addition, this coating composition also comprises other composition that routine is used for coating.According to a preferred embodiment, for cast(ing) surface being produced the persistence effect, the solid content meter of coating based composition, the content of this metallic addition in this coating composition is at least 10 weight %, preferably be at least 15 weight %, especially preferably be at least 20 weight %.

Explain that as preamble coating is not preferred for realizing the alloying of cast(ing) surface layer, but the identical composition of foundry goods part (being the part in its body) that surface or edge shell is had basically arrange with the spaced surface of foundry goods.

Therefore, preferably, the solid content meter of coating based composition, the content of the metallic addition in the coating composition are chosen as less than 50 weight %, especially less than 40 weight %, especially preferably less than 35 weight %.

As already mentioned, this metallic addition can only contain at least a in the above-mentioned metal, at least a metal in preferred manganese, nickel and the copper.Yet according to an embodiment, described at least a metal can also be contained in the metallic addition by alloy form.According to an embodiment, this metal is contained in the metallic addition with the ferroalloy form.In elemental iron, the content of iron in metallic addition is preferably 20～80 weight %, especially is 30～70 weight %.

Except metal and iron, this alloy also can contain other composition.

According to another embodiment, this metallic addition contains aluminium as composition, and in element aluminum, the aluminium content in the metallic addition especially is chosen as less than 10 weight %, preferably less than 8 weight %.According to an embodiment, metallic addition contains the aluminium greater than 2 weight %.Coating embodiment according to the present invention, the aluminium content in the metallic addition is 2～8 weight %, preferred 3～6 weight %, preferred especially 3～5 weight %.

According to an embodiment, metallic addition also can the silicon alloy form use.Silicone content in this silicon alloy is preferably 20～80 weight %, is preferably 50～70 weight % especially.

Metallic addition also can contain other composition, particularly metal, and its content especially is chosen as less than 2 weight %, preferably less than 1 weight %.

These other compositions are preferably selected from cerium, magnesium, chromium and molybdenum.

Based on the metallic addition meter, the content of these alloying components is preferably 0.01～2 weight %, is preferably 0.1～1 weight %.But this metallic addition also calcic as other alloying component.The content of calcium is preferably 0.2～2 weight %, preferred especially 0.5～1.5 weight %.

The granularity of this metallic addition should preferably not wanted too little, if particularly metal (preferably manganese, nickel and copper) is like this when being contained in the metallic addition with element state, its reason is that other composition that can increase metallic addition and coating composition reacts, for example, and oxidized risk.On the other hand, this granularity preferably should not be too big, otherwise metallic addition for example may sedimentation in coating composition, causes metallic addition to apply inequality thus on mould surface.

Particle mean size (the D of preferable alloy additive ₅₀) less than 0.5mm, preferably less than 0.4mm, especially preferably less than 0.3mm.Particle mean size (D ₅₀) for example can calculate by sieve analysis or by the laser particle size determination method.The metallic addition that comprises in the coating of the present invention has high relatively density usually, and therefore rapid subsidence in coating.Yet this sedimentation can be slowed down by adding leafing agent.Also can make that described introducing agent keeps evenly being suspended in the coating by reducing the sedimentation that granularity further reduces this introducing agent.Another advantage is when utilizing the spraying apparatus applied coatings, to adopt to have the nozzle that fine-grained metallic addition is not easy to stop up spraying apparatus.The particle mean size of introducing agent is especially preferably less than 0.3mm.Yet along with reducing of granularity, the specific surface of metallic addition increases, therefore with coating in contained liquid for example the reactivity of water also increase.Under the situation of metallic addition and for example water reaction, to observe gas and produce, it causes forming foam.Coating is pumping or spraying effectively more just.Therefore this particle mean size is preferably greater than 50 μ m, is preferably greater than 80 μ m especially.Metallic addition more preferably uses with the granularity of 80～300 μ m preferably with 20～1000 μ m.

Preferably provide according to coating composition of the present invention with the form of thickener or suspended substance.In this embodiment, coating composition comprises carrier fluid.This carrier fluid is chosen as suitably and can evaporates fully in the normal condition of casting of metals.Therefore, the boiling point of this carrier fluid under normal pressure should be preferably less than about 130 ℃, preferably less than 110 ℃.

This carrier fluid can partially or completely be formed by water.Yet, may observe the oxidation of metallic addition, particularly like this when metallic addition exists with the alloy attitude of metal element attitude or metal element.Therefore, according to a preferred embodiment, this coating composition comprises the solvent of being made up of organic solvent to small part.

The oxidation of metallic addition by the high-load organic solvent for example alcohol suppress.As another advantage, this coating can used the back by the burning-off solvent and very easily dry.

If organic solvent is contained in the coating composition, then its content in carrier fluid especially is chosen as greater than 20 weight %, is preferably greater than 30 weight %, the special 40 weight % that are preferably greater than.

This carrier fluid can be made up of organic solvent fully.Yet according to an embodiment, the content of organic solvent is lowlyer also optional in the carrier fluid.According to an embodiment, the content of organic solvent is less than 90 weight %, according to another embodiment, less than 80 weight %, according to another embodiment, less than 70 weight % in the carrier fluid.

The example of appropriate organic solvent comprises aliphatic hydrocarbon, clicyclic hydrocarbon or the aromatic hydrocarbon that preferably contains 5～15 carbon atoms; Or the ester of aliphatic carboxylic acid, wherein this carboxylic acid pure composition of preferably containing 2～20 carbon atoms and this fat preferably contains 1～4 carbon atom.The example of other preferred organic comprises the ketone that preferably contains 4～20 carbon atoms.Ester also can be suitable as solvent, also can use polyethylene glycol in this case.

According to a preferred embodiment, this solvent to small part is made up of at least a alcohol that preferably comprises 1～10 carbon atom.Exemplary alcohol is ethanol, normal propyl alcohol, isopropyl alcohol and butanols.

If use the component of alcohol as carrier fluid, then its content is preferably greater than 50 weight % based on carrier fluid weight meter, is preferably greater than 60 weight %.

Except that comprising the component of having mentioned, also can comprise other components that routine is used for coating according to coating composition of the present invention.

According to a preferred embodiment, coating composition of the present invention comprises at least a pulverous refractory material.This refractory material is used for the hole of pressurized mould and infiltrates to prevent liquid metal.Can realize also that by this refractory material the heat between mold and the liquid metal isolates.Can use refractory material commonly used in casting of metals as refractory material.The example of suitable refractory material comprises quartz, aluminium oxide, zirconia, alumina silicate such as pyrophyllite, kyanite, andalusite or fire clay, zircon sand, zirconium silicate, olivine, talcum, mica, graphite, coke, feldspar, diatomite, kaolin, calcined kaolin, kaolinite, metakaolinite, iron oxide and bauxite.

This refractory substance provides with powder type.Granularity is chosen as and forms rock-steady structure in coating, and this coating can preferably successfully be distributed on the wall of mold with spraying apparatus.The particle mean size of this refractory material is preferably 0.1～500 μ m, preferred especially 1～200 μ m.Especially, its fusing point is higher than at least 200 ℃ of liquid metal temperature and is suitable as refractory material with material that metal does not react.

The solid content meter of coating based composition, the content of this refractory material especially are chosen as greater than 10 weight %, are preferably greater than 20 weight %, are preferably greater than 30 weight % especially.According to an embodiment, the content of this refractory material is less than 80 weight %, according to another embodiment, less than 70 weight %, according to another embodiment, less than 60 weight %.

According to an embodiment, can comprise a kind of leafing agent according to coating of the present invention.Leafing agent increases the viscosity of coating, makes solid constituent not sedimentation or only a small amount of sedimentation in suspension of coating.For improving viscosity, can use organic material and inorganic material or these mixtures of material.The example of suitable inorganic leafing agent comprises the high swelling property clay.

For stoping the solid constituent sedimentation in the coating and can being implemented in evenly using on the mold again simultaneously, the viscosity of this coating especially is chosen as 1000～3000mPas, is preferably 1200～2000mPas especially.

Then, metallic addition can be bordering on equably and be distributed in the coating, and therefore also can be administered to equably on the wall of mold.Can control the amount that is applied to the metallic addition on the mould surface very exactly thus.

Silicon bi-layer hydrochlorate and three layer silicates all can be used as the phyllosilicate of high swelling property, as Attagel, serpentine, kaolin, terre verte (as saponite, montmorillonite, beidellite and Gao Shi), vermiculite, illite, hectorite and mica.Hectorite is also given the coating thixotropic behavior, easily forms protective layer thus on mold, because this coating is no longer mobile after using.Because this phyllosilicate contains water and this water coating being administered to evaporation on the hot-cast mould that temperature is about 250～350 ℃, so the amount of this clay is preferably minimum in the intermediate layer.Based on the solid content meter of this coating, the amount of the phyllosilicate of this high swelling property is preferably 0.01～5.0 weight %, is preferably 0.1～1.0 weight % especially.

Preferred organic thickening agent is as leafing agent, because it can be dried to it discharges water hardly when contacting with liquid metal degree after using protective layer.The available example of organic floating agent comprises polymers capable of swelling, as carboxymethyl cellulose, methylcellulose, ethyl cellulose, hydroxyethylcellulose and hydroxypropyl cellulose, plant mucilage, polyvinyl alcohol, polyvinylpyrrolidone, pectin, gelatin, agar and many phthaleins and alginates.

According to a preferred embodiment, coating according to the present invention comprises at least a adhesive as other component.This adhesive can make coating or is fixed on better on the wall of mold by the protective finish of this coating manufacturing.In addition, this adhesive has increased the mechanical stability of this protective layer, makes less erosion only to occur under the effect of liquid metal.The preferred irreversible curing of this adhesive, thus wear-resistant coating obtained.The adhesive that can not soften again when contacting with air humidity.Can be included in all adhesives that use in the coating.Can use inorganic bond and organic bond.For example clay, particularly bentonite can be used as adhesive.

The special curable adhesive that uses.For example can form agent by free radical in olefin(e) acid ester system and realize solidifying, this free radical forms agent and takes place to decompose and the formation free radical through high-energy ray such as ultraviolet irradiation the time.

Other exemplary adhesive comprises starch, dextrin, peptide, polyvinyl alcohol, polyvinyl acetate ester copolymer, polyacrylic acid, polystyrene dispersions and/or polyvinyl acetate-polypropylene ester dispersion.Usually preferred use can be introduced in water-based system, pure system or water-pure system and the adhesive composition that does not soften again after solidifying under the air humidity effect.

According to a preferred embodiment, use alkyd resins as adhesive, it is preferably not only that water soluble also dissolves in the lower alcohol such as ethanol, normal propyl alcohol and isopropyl alcohol that preferably contains 2～4 carbon atoms.

According to another embodiment, coating compound of the present invention contains silica and bathes glue as adhesive.Silicon dioxide gel preferably by in and waterglass make.The specific surface of contained amorphous silicas colloidal sol is preferably 10～1000m ²/ g, preferred especially 30～300m ²/ g.

The solid weight meter of coating based composition, the content of adhesive are preferably 0.1～20 weight %, are preferably 0.5～5 weight % especially.

According to another preferred embodiment, coating graphitiferous part.It helps forming sheet carbon on the interface between foundry goods and the mold.Coating based weight meter, the content of graphite are preferably 1～30 weight %, are preferably 5～15 weight % especially.

Coating composition of the present invention also can be chosen wantonly and comprise other composition that routine is used for coating, as wetting agent, defoamer, pigment, colouring agent or antimicrobial.The content of this other composition of class is preferably less than 1 weight % in the instant coating compound.

Can use HSB-value for example to be at least the anion surfactant of 7 middle polarity and high polarity and non-anion surfactant as wetting agent.The example of this class wetting agent is a dioctyl sulfosuccinate disodium.Based on instant coating composition meter, the consumption of wetting agent especially is 0.01～1 weight %, preferred 0.05～0.3 weight %.

Can use defoamer or antifoam agent, to prevent when making coating composition or applied coatings composition, forming foam.The formation foam can cause the hole in uneven bed thickness and the coating when the applied coatings composition.For example can use silicone oil or mineral oil as defoamer.Based on instant coating composition meter, the consumption of defoamer is preferably 0.01～1 weight %, is preferably 0.05～0.3 weight %.

Conventional pigment that uses and colouring agent can be chosen wantonly and be used for coating composition of the present invention.It is added realizing for example contrast between the different layers, or produce stronger coating and the foundry goods effect of demarcating.The example of pigment comprises red and yellow iron oxide and graphite.The example of colouring agent comprise commercially available colouring agent as

Colour system (BASF AG, Ludwighafen, DE).The solid content meter of coating based composition, the amount of contained colouring agent and pigment especially are 0.01～10 weight %, are preferably 0.1～5 weight %.

According to another embodiment, coating composition contains antimicrobial, to prevent bacterial infection and to avoid thus the rheological characteristic and the cohesive force of adhesive are had a negative impact.If the carrier fluid that comprises in the coating composition mainly is made up of water, when form provided, this was particularly preferred to coating composition promptly of the present invention with " water paint ".The example of suitable antimicrobial agents in order comprises formaldehyde, 2-methyl-4-isothiazoline-3-ketone (MIT), 5-chloro-2-methyl-4-isothiazoline-3-ketone (CIT) and 1,2-benzisothiazole-3-ketone (BIT).Preferred MIT, BIT or its mixture of using.Based on the weight meter of instant coating composition, the amount of normally used antimicrobial is 10～1000ppm, is preferably 50～500ppm.

The solid content of this instant coating composition especially is chosen as 10～60 weight %, is preferably 20～50 weight %.

Can make according to conventional methods according to coating composition of the present invention.For example can make by the following method: provide water, and the clay that will play the leafing agent effect is scattered in wherein through high-shear mixer according to coating composition of the present invention.Then stir adding refractory composition, pigment and colouring agent and metallic addition, up to forming uniform mixture.Stir at last and add wetting agent, defoamer, antimicrobial and adhesive.

Coating composition of the present invention can be used as the coating manufacturing and the distribution of instant prescription.Yet, also can the conc forms produce and market according to coating of the present invention.In this case, add the required carrier fluid amount of dope viscosity that expectation is provided and density to make instant coating.In addition, can also be according to coating composition of the present invention with the form produce and market of kit, wherein for example solids content and solvent composition and be stored in the container separately.This solids content can be used as the pulverulent solids mixture and places container separately.Can choose other liquid parts such as adhesive, wetting agent, humidizer/defoamer, pigment, colouring agent and the antimicrobial of use wantonly also can pack container separately into and place this kit.Solvent composition can be included in the common vessel by the optional composition that uses when needing, or can with the container individualism of other optional member to separate.For making instant coating, the solids content of appropriate amount, optional other composition and solvent composition can be mixed mutually.Coating of the present invention especially is 20～80 weight % with the solid content under the state based on instant coating composition meter shortly, is in particular 30～70 weight %.In addition, the coating composition of the present invention that also can provide its solvent composition only to form at first by water.By add based on the water paint meter preferably be for example volatile alcohol or the alcohol mixture of 40～200 weight %, preferred alcohol, propyl alcohol, isopropyl alcohol and its mixture can be made instant alcohol coating by this water paint.The solid content of this alcohol coating is preferably 20～60 weight %, is preferably 30～40 weight %.

Use as, can regulate other characterisitic parameter of this coating composition according to the expectation of this coating composition as basic coating or as the lid coating with by the bed thickness of the prepared coating of coating composition.Thus in a preferred embodiment, the viscosity that is used to apply the coating composition of the present invention of pattern and core in foundary industry is 11～25s, and more preferably 12～15s (measures according to DIN 53211; Flow cup is 4mm, Ford viscosity cup).The preferred density of instant coating composition is 0～120 ° of B é, and more preferably 30～50 ° of B é (measure based on Baum é-buoyancy method; DIN 12791).

Coating composition according to the present invention is suitable for applying mold.Terminology used here " mold " comprises makes required all types of die bodys such as core rod, pattern and the metal pattern of foundry goods.The local coating that also comprises mold according to the purposes of coating composition of the present invention.

Therefore, the invention still further relates to the method for making mold, wherein at least one die cavity in the mold is coated with good grounds coating composition of the present invention.

In the method:

-mould material mixture that contains at least a fire-resistant Modeling Material and adhesive is provided,

-the basic mode that this mould material mixture is configured as comprise die cavity and

-apply the face of the die cavity of this basic mode at least with aforementioned coating composition.

At first make basic mode by mould material mixture with known method.For making mould material mixture, fire-resistant Modeling Material is mixed with adhesive, be configured as the parts of basic mode or basic mode then.This basic mode is in its basic in shape part corresponding to mold or mold.Yet basic mode does not comprise any coating with coating.

Can use all refractory materials that the mold of making foundary industry uses always as fire-resistant Modeling Material.The example of the fire-resistant Modeling Material that is suitable for comprises quartz sand, zircon sand, olivine sand, aluminium silicate sand and chromite sand or its mixture.The preferred quartz sand that uses.Fire-resistant Modeling Material should have enough granularities, so that have sufficiently high porosity by the die body of mould material mixture manufacturing, overflows for can make volatile compound in casting cycle.Preferred at least 70 weight %, the granularity≤290 μ m of the fire-resistant Modeling Material of preferred especially at least 80 weight %.The particle mean size of fire-resistant Modeling Material preferably should be 100～350 μ m.For example can determine granularity by sieve analysis.This fire-resistant Modeling Material should exist with the shot attitude, makes adhesive or liquid catalyst for example being applied to effectively on the particle of this fire-resistant Modeling Material in the blender.

According to an embodiment, the antiquated sand that can use regeneration is as fire-resistant Modeling Material.By removing bigger aggregate and optional separated antiquated sand particle in the antiquated sand.This antiquated sand through machinery or heat treatment after remove dust and can reuse.The acid balance of preferred this regeneration antiquated sand of check before reusing.Particularly when heat was regenerated, accessory substance such as carbonate contained in the sand can be transformed into corresponding oxide, and described oxide reacts in the mode of alkali then.If use the adhesive that solidifies by acid catalysis, then in the case, this can be neutralized by the basic component of regeneration antiquated sand as the acid that catalyst adds.For example in the machinery regeneration of antiquated sand, acid can be retained in the antiquated sand, also need consider this acid when making adhesive, because for example can shorten the processing time of this mould material mixture.

This fire-resistant Modeling Material should be dry.This fire-resistant Modeling Material especially comprises the water less than 1 weight %.For preventing the effect premature hardening of this adhesive owing to heat, this fire-resistant Modeling Material should be too not warm.The temperature of fire-resistant Modeling Material should be preferably 20～35 ℃.Can choose wantonly fire-resistant Modeling Material is cooled off or heats.

Can use routine to be used to make all adhesives of the used mold of casting of metals as adhesive.Can use inorganic bond also can use organic beginning mixture.As inorganic bond available water glass for example, it can solidify under heat effect or by introducing carbon dioxide.Exemplary organic bond comprise polyurethane do not have baking adhesive and cold box binder, based on the adhesive of furane resins or phenol resin, or epoxy-acrylate adhesive.

Adhesive based on polyurethane is made of two kinds of compositions usually, and first composition contains phenol resin, and second composition contains PIC.This in two composition mix with fire-resistant Modeling Material, and mould material mixture is introduced pattern, compacting and then sclerosis by hammering, blowing, injection or other method.According to the method for catalyst being introduced in the mould material mixture, can divide into " polyurethane does not have baking " and " polyurethane ice chest method ".

In no baking, before mould material mixture being added in the mold and solidifying, the liquid catalyst of liquid tertiary amine is normally introduced in the mould material mixture.For making mould material mixture, phenol resin, PIC and curing catalysts are mixed with fire-resistant Modeling Material.For example can carry out as follows: at first this fire-resistant Modeling Material is sealed with adhesive ingredients, adds another kind of composition then.With curing catalysts be added to this two composition one of in.Made mould material mixture need have sufficiently long process time, makes mould material mixture have time enough to carry out plastic deformation and is processed into mold.For this reason, this polymerization need be carried out quite slowly, so that this mould material mixture can not solidify in hold-up vessel or in the feeding pipe.On the other hand, for obtain sufficiently high production capacity when making mold, solidifying necessarily can not be too slow.For example, can be added the influence of retarding agent process time, and described retarding agent can slow down the solidification process of mould material mixture.Suitable retarding agent for example is a phosphoryl chloride phosphorus oxychloride.

In the ice chest method, mould material mixture is introduced in the mould under catalyst-free.Then the gaseous state tertiary amine is imported in the mould material mixture, and optional can the mixing with inert carrier gas.When contacting with gaseous catalyst, this adhesive is bonding rapidly, thereby obtains high production capacity when making mold.

Adhesive composition based on polyurethane contains polyol component and PIC composition, can be returned to known composition in the case.

The PIC composition of adhesive can comprise aliphatic isocyanate, alicyclic isocyanate or aromatic isocyanate.The per molecule PIC especially comprises at least 2 isocyanate groups, especially 2～5 isocyanate groups.According to desired characteristics, also can use the mixture of isocyanates.Used isocyanates can be made up of monomer, oligomer and mixture of polymers, therefore is called PIC below.

Any PIC that can use in the foundary industry field conventional polyurethane binder that is used for mould material mixture is as the PIC composition.Suitable PIC comprises aliphatic polymeric isocyanate such as hexamethylene diisocyanate, alicyclic polymeric isocyanate as 4,4 '-dicyclohexyl methyl hydride diisocyanate and its dimethyl derivative.The example of suitable aromatic polyisocyanate comprises Toluene-2,4-diisocyanate, 4-vulcabond, Toluene-2,4-diisocyanate, 6-vulcabond, 1,5-naphthalene diisocyanate, xylyl vulcabond and methyl-derivatives thereof, diphenyl methane-4,4 '-vulcabond and polymethylene polyphenol PIC.

Though conventional PICs all on the principle all can generate crosslinked polymer architecture with the phenol resin reaction, but preferably use aromatic polyisocyanate, special preferred polymethylene polyphenol PIC such as commercially available diphenyl methane-4,4 '-vulcabond, its isomer and higher homologues.

This PIC can material form use, and is dissolvable in water in atent solvent or the reactive solvents.Reactive solvents means the solvent with reactive group, and it is incorporated in the structure of adhesive when adhesive.PIC preferably uses with dilute form, reason be solution can make the film of adhesive seal the particle of fire-resistant Modeling Material better than low viscosity.

PIC or its solution in organic solvent uses with the concentration that is enough to polyol component is solidified, and based on the weight meter of polyol component, it typically is 10～500 weight %.The weight meter that is preferably based on polyol component uses 20～300 weight %.Liquid polyisocyanates can be used with non-dilute form, and solid-state or viscosity PIC is dissolved in the organic solvent.80 weight % at the most especially are 60 weight % at the most, and special preferred the isocyanate prepolymer composition of 40 weight % can be by solvent composition at the most.

The use amount of PIC be preferably the number that makes isocyanate groups be polyol component the free hydroxyl group number 80～120%.

Can use all polyalcohols that in polyurethane binder, use as polyol component.Polyol component comprise can with at least 2 hydroxyls of the isocyanate groups of PIC composition reaction, with crosslinked with adhesive when solidifying, make the higher intensity of mold acquisition of curing thus.

Preferred use in the presence of the metal of catalytic amount in liquid phase in the condensation by phenol and aldehyde (preferably formaldehyde) obtains under 180 ℃ at the most phenol resin as polyalcohol.The method itself that is used to make this class phenol resin is known.

Polyol component preferably uses with form liquid or that be dissolved in the organic solvent, so that adhesive can be evenly distributed on the fire-resistant Modeling Material.Polyol component preferably uses with no aquosity, and its reason is that the reaction of isocyanate prepolymer composition and water is a kind of side reaction of not expecting.Non-in this article water or the anhydrous water content that is meant this polyol component are preferably less than 5 weight %, preferably less than 2 weight %.

Term " phenol resin " is meant the product of phenol, amphyl, bis-phenol and higher phenols condensation product and aldehyde.The composition of phenol resin depends on the specific raw material of selecting for use, material rate and reaction condition.For example the existence of catalyst type, reaction time and reaction temperature and solvent and other material all plays an important role.

This phenol resin exists as the mixture of different compounds usually, and contains addition compound product, condensation product and unreacted starting compounds as very phenol, bis-phenol and/or the aldehyde of different proportion.

" addition compound product " is meant the product or the condensation product of at least one hydrogen on the phenol that is unsubstituted before the wherein organic principle replacement." condensation product " is meant the product with two or more phenol rings.

Phenol resin is to produce as the condensation reaction of phenol and aldehyde, and according to quantitative ratio, reaction condition and the catalyst system therefor of precipitate, can be divided into two series products: novolac resin and resole resin.

Novolac resin is soluble, fusible, non-self-curing and oligomer bin stability, and its molecular weight is about 500～5000g/ mole.Its in the presence of acidic catalyst by aldehyde and phenol with 1:＞1 mol ratio produces through condensation reaction.Novolac resin is the phenol resin that does not contain methylol groups, and wherein benzene nucleus links to each other through methylene bridge.After adding curing agent such as formaldehyde releaser (preferred hexa), it is crosslinking curing at high temperature.

Resole resin is the mixture of the hydroxymethyl phenol that links to each other with the methylene ether bridge through methylene bridge, and can by under the optional situation that has catalyst such as a base catalyst by aldehyde and phenol with 1:＜1 molar ratio reaction produces.Its molecular weight M _W≤ 10000g/mol.

The phenol resin that is particularly suitable as polyol component is known by name " o-o ' " or " high-ortho " novolac resin or benzylic ether resin.They can be obtained by phenol and aldehyde condensation reaction in weak acid medium by using appropriate catalyst.

The catalyst that is suitable for making the benzylic ether resin comprises the divalent ion salt of metal such as Mn, Zn, Cd, Mg, Co, Ni, Fe, Pb, Ca and Ba.The preferred zinc acetate that uses.Used amount is unimportant.Based on the total amount meter of phenol and aldehyde, the typical amounts of metallic catalyst is 0.02～0.3 weight %, is preferably 0.02～0.15 weight %.

The phenol that all routines are used all is applicable to the manufacturing phenol resin.Except that the phenol that is unsubstituted, also can use phenol or its mixture of replacement.This phenolic compounds is unsubstituted at two ortho positions or at an ortho position with in contraposition, so that can carry out polymerisation.Remaining available ring carbon atom is substituted.Substituent selection is specifically restriction, as long as this substituting group has no adverse effect to the polymerisation of phenol or aldehyde.The example of substituted phenol comprises alkyl-substituted phenols, alkoxyl substituted phenol and aryloxy group substituted phenol.

Above-mentioned substituting group for example has 1～26, preferred 1～15 carbon atom.The example of suitable phenol comprises orthoresol, metacresol, paracresol, 3,5-dimethylbenzene, 3,4-dimethylbenzene, 3,4,5-trimethyl phenol, 3-ethyl phenol, 3,5-diethyl phenol, to butylphenol, 3,5-dibutyl phenol, right-amylic phenol, cyclohexyl phenol, to octyl phenol, to nonyl phenol, 3,5-dicyclohexyl phenol, to crotyl phenol, to phenyl phenol, 3,5-dimethoxy phenol and to phenoxy group phenol.

Phenol itself especially preferably.Senior condensation phenol also is suitable as bisphenol-A.In addition, the multivalence phenol that contains more than 1 phenolic hydroxyl group also is suitable.Preferred multivalence phenol contains 2～4 phenolic hydroxyl groups.The particular instance of suitable multivalence phenol comprises pyrocatechol, resorcinol, quinhydrones, 1,2,3,-thrihydroxy-benzene, fluoro glycine, 2,5-dimethyl resorcinol, 4,5-dimethyl resorcinol, oreinol diphenol or 5 one ethyl resorcinols.

Also can use the phenol of different monovalencies and multivalence and/or replacement and/or the condensation polyol component that becomes to assign to make.

In one embodiment, the phenol of using general formula I is made the phenol resin composition:

Formula I

Wherein A, B and C are selected from hydrogen atom independently of one another, for example can comprise 1～26, the branched-chain or straight-chain alkyl of preferred 1～15 carbon atom, for example can comprise 1～26, the side chain or the straight chain alkoxyl of preferred 1～15 carbon atom, for example can comprise 1～26, the side chain or the straight alkenyloxy of preferred 1～15 carbon atom, or aryl or alkylaryl such as two phenyl.

The aldehyde of formula R-CHO be fit to be made the phenol resin composition: wherein R be hydrogen atom or contain preferred 1～8, the carbon atom base of preferred especially 1～3 carbon atom.Particular instance comprises formaldehyde, acetaldehyde, propionic aldehyde, furfuryl group aldehyde and benzaldehyde.Especially preferably use formaldehyde, it can contain aquosity, as PARA FORMALDEHYDE PRILLS(91,95) or three

Alkane uses.

For making phenol resin, should use the aldehyde that waits molal quantity at least based on phenol composition molal quantity meter.Aldehyde to the mol ratio of phenol be preferably 1: 1.0～2.5: 1, be preferably 1.1: 1～2.2: 1 especially, especially be preferably 1.2: 1～2.0: 1.

The phenol resin composition is by well known to a person skilled in the art the method manufacturing.Phenol and aldehyde transform in preferred temperature less than 130 ℃ with substantially anhydrous condition in that the situation that has two valence metal ions is following.The water that is generated is removed through distillation.Can add suitable entrainer such as toluene or dimethylbenzene to reactant mixture, or under reduced pressure distill.

Phenol composition and aldehyde are reacted, be preferably formed the benzylic ether resin with adhesive as mould material mixture.Forming alkoxy-modified also available one-step method of phenol resin or two-step method (EP-B-0177871 and EP 1137500) with primary aliphatic alcohols or the reaction of fatty secondary alcohol carries out.In one-step method, phenol, aldehyde and alcohol react having in the presence of the appropriate catalyst.In two-step method, at first make unmodified resin, then react with alcohol.When using alkoxy-modified phenol resin, there is not restriction in mol ratio, but pure composition is preferably with alcohol: phenol uses less than 0.25 mol ratio, makes less than 25% methylol by etherificate.Suitable alcohol comprises the primary aliphatic alcohols and the fatty secondary alcohol of hydroxyl and 1～10 carbon atom.The suitable primary alconol and the example of secondary alcohol comprise methyl alcohol, propyl alcohol, n-butanol and n-hexyl alcohol.Special particular methanol and n-butanol.

Phenol resin preferably is chosen as can be crosslinked with the PIC composition.The phenol resin that comprises the molecule with at least two hydroxyls is particularly suitable for constituting network.The phenol resin composition of adhesive composition or isocyanate prepolymer composition are preferably as the solution use in organic solvent or in the organic solvent combination.For adhesive ingredients being remained on enough low viscosity state, solvent may be necessary.For realizing even crosslinked and its laxity of fire-resistant Modeling Material, solvent is necessary especially.

All solvents that routine is used for this class adhesive composition of foundary industry all can be used as based on the PIC composition of the adhesive composition of polyurethane or the solvent of polyol component.For example the polar organic solvent of oxygen enrichment is suitable as solvent.Particularly suitable is dicarboxylic ester, glycol ether ester, ethylene glycol diester, ethylene glycol diether, cyclic ketones, cyclic ester or ring carboxylate.Preferred dicarboxylic ester, cyclic ketones and the ring carboxylate of using.Dicarboxylic ester has general formula R ^aOOC-R ^b-COOR ^a, radicals R wherein ^aIndependent of separately containing 1～12, the alkyl of preferred 1～6 carbon atom, R ^bBe to contain 1～12, the alkylidene of preferred 1～6 carbon atom i.e. two valency alkyl.R ^bAlso can contain one or more carbon-to-carbon double bond.Example comprises the dimethyl esters of the carboxylic acid that contains 4～10 carbon atoms, and for example it can (DBE) obtain with trade name " dibasic ester " from Invista International S.a.r.l (Genf, Switzerland).Glycol ether ester is that general formula is R ^c-O-R ^d-OOCR ^eCompound, R wherein ^cBe the alkyl that contains 1～4 carbon atom, R ^dBe ethylidene, propylidene or low PEO or expoxy propane, R ^eIt is the alkyl of 1～3 carbon atom.Preferred glycol ether acetate such as butyl glycol acetate.The ethylene glycol diester is corresponding to have general formula R ^eCOO-R ^dOOCR ^e, R wherein ^dAnd R ^eAs defined above, radicals R ^eSelect alone separately.Preferred ethylene acetate such as propylidene ethylene acetate.The general formula of ethylene glycol diether can be R ^c-O-R ^d-O-R ^c, R wherein ^cAnd R ^dAs defined above, radicals R ^cSelect alone separately.Suitable ethylene glycol diether for example is the dipropylene ethylene glycol dimethyl ether.Cyclic ketones, cyclic ester and the ring carboxylate that contains 4～5 carbon atoms also are fit to.The ring carboxylate that is fit to for example is the propylidene carboxylate.Alkyl and alkylidene also can respectively do for oneself side chain or straight chain.

Solvent in adhesive composition preferably should not be too high, because solvent for example can cause producing bad smell or causing being fuming during casting by the manufacturing of the mold of this mould material mixture manufacturing and can evaporation between the operating period thus.The content of solvent is preferably less than 50 weight %, especially preferably less than 40 weight %, especially preferably less than 35 weight % in adhesive composition.

For making mold, as mentioned above, adhesive is mixed with fire-resistant Modeling Material form mould material mixture.Make mold if having baking based on polyurethane, then also can early oneself be added with appropriate catalyst in this mould material mixture.Preferably liquid amine is added in the mould material mixture.The pK of these amine _bValue is preferably 4～11.The example of appropriate catalyst comprises the 4-alkyl pyridine, wherein alkyl contain 1～4 carbon atom, isoquinolin, propenyl pyridine such as phenylpyridine, pyridine, acryline, 2-methoxypyridine, pyridazine, 3-chloro-pyridine, quinoline, just-methylimidazole, 4,4 '-bipyridyl, phenyl propyl pyridine, 1-tolimidazole, 1,4-thiazine, N, N '-dimethyl benzyl amine, triethylamine, triphenylamine, N, N '-dimethyl-1,3-propane diamine, N, N '-dimethylethanolamine and triethanolamine.Catalyst can be chosen wantonly and use atent solvent as 2,2,4-trimethyl-1,3-pentanediol-diisobutyrate or fatty acid ester dilution.Based on the weight meter of polyol component, add catalyst amount be 0.1～15 weight %.

Then, introduce in the mould mould material mixture and compacting with conventional method.Mould material mixture is solidified to form mold.During curing mold should preferably keep its profile.

If implement solidification process based on polyurethane ice chest method, then guide the mould material mixture of gaseous catalyst by being shaped.Can use conventional catalyst in ice chest method field as catalyst.Especially preferably use amine as catalyst, especially preferably be gaseous state or aerocolloidal dimethylethyl amine, dimethyl n propyl group amine, dimethyl isopropylamine, dimethyl-n-butylamine, triethylamine and Trimethylamine.

According to another preferred embodiment, use furane resins or phenol resin as adhesive, this mould material mixture solidifies in the catalytic action of strong acid according to " furans does not have baking " method.

These furane resins and phenol resin demonstrate extraordinary resolution characteristic during casting.Furane resins or phenol resin decompose under the heat effect of liquid metal, and mold loses intensity.Therefore behind casting cycle, can from cavity, take out core easily, choose wantonly behind pre-vibration foundry goods and take out.

Be contained in reactive furane resins in " furans does not have the baking adhesive " as first composition and comprise furfuryl alcohol as main component.Furfuryl alcohol can and form polymer in id reaction in the presence of the acidic catalyst.Do not have the baking adhesive for making furans, do not use pure furfuryl alcohol usually, but in furfuryl alcohol, add other compound that resin is advanced in polymerization.The example of this compounds comprises aldehydes such as formaldehyde or furfural, ketone such as acetone, phenols, urea or polyalcohol such as sugar alcohol or ethylene glycol.Also can add in resin influences resin properties such as its flexible other composition, for example can add melamine with in conjunction with free formaldehyde.

Furans does not have the baking adhesive usually with following method manufacturing, promptly at first produces the precondensate that contains furfuryl group by for example urea, formaldehyde and furfuryl alcohol under acid condition.This reaction condition is chosen as the slight polymerization that furfuryl alcohol only takes place.Dilute these precondensates with furfuryl alcohol then.Also can use resole resin to make furans and not have the baking adhesive.Resole resin is by the polymerization manufacturing of the mixture of phenol and formaldehyde.These resole resins dilute with furfuryl alcohol subsequently.

Second composition that furans does not have the baking adhesive forms acid.The alkaline components that on the one hand should acid neutralizes and comprise in the fire-resistant Modeling Material, what catalysis should the reactivity furane resins on the other hand is crosslinked.

Usually use aromatic sulfonic acid as acid, at some in particular cases, also use phosphoric acid or sulfuric acid.To be concentration with conc forms use greater than 75% concentrate phosphoric acid.Yet it is only applicable to contain the catalytic curing of the furane resins of higher share urea.This resinoid nitrogen content is greater than 2.0 weight %.Sulfuric acid can be used as strong relatively acid and joins in the furane resins of weak acid initator as solidification process.Yet, during casting, have the smell of typical sulphur compound to emit.In addition, exist sulphur to be absorbed and influence the danger of its characteristic by cast material.Usually use sulfonic acid as catalyst.Special toluenesulfonic acid, xylene monosulfonic acid and the benzene sulfonic acid of using, this is because it has good usability and high acid strength.

Comprise phenol resin that resole resin promptly makes with excess formaldehyde as the reaction resin composition as the phenol resin of the nothing of second largest group theobromine catalytic curing baking adhesive.Compare with furane resins, phenol resin demonstrates obviously little reactivity, and needs strong sulfonic acid as catalyst.Phenol resin has high relatively viscosity, and viscosity also can increase when the resin long term storage.Viscosity increases fast when temperature is lower than 20 ℃ especially, must heat sand thus, adhesive evenly can be applied on the surface of sand grains.After phenol not being had a baking adhesive is applied on the fire-resistant Modeling Material, should handle mould material mixture as far as possible, making not can be owing to solidifying the quality deterioration that makes mould material mixture in advance, otherwise can cause the strength deterioration of the mold made by mould material mixture.When using phenol not have the baking adhesive, the flowable of mould material mixture is bad usually.Therefore must careful this mould material mixture of compacting when making mold, so that mold obtains high strength.

The manufacturing of mould material mixture and processing should be carried out under 15～35 ℃.Cross low temperature meeting because phenol does not have the high viscosity of baking of resin and can not easily handle.Premature setting owing to adhesive when temperature is higher than 35 ℃ has shortened the processing time.

After the casting, also can handle again, also can use mechanical means or by the use of thermal means or mechanical/thermal combined method to handle again in this case the mould material mixture that does not have the baking adhesive based on phenol.

Acid is applied on the loose refractory material, thereby obtains scribbling sour fire-resistant Modeling Material.Available conventional method is applied to acid on the fire-resistant Modeling Material, as acid is sprayed on the fire-resistant Modeling Material.Binding agent based weight is also calculated (when promptly need not considering used solvent) with pure acid, and the amount of acid is preferably 5～45 weight %, preferred especially 20～30 weight %.Do not exist and do not have enough low viscosity as tartaric acid, then acid is dissolved in the suitable solvent so that be distributed on the particle of fire-resistant Modeling Material with the form of film with liquid state.Exemplary solvent comprises the mixture of water or alcohol or water and alcohol.Yet, particularly when making water, make dense as far as possible solution, be retained to minimum with the water yield that will introduce in adhesive or the mould material mixture.Make by the abundant homogeneity of mixture that fire-resistant mold is trembled and acid is formed, so that acid is evenly distributed on the particle.

But use the adhesive of acid cure then to the fire-resistant Modeling Material that scribbles acid.Calculate based on fire-resistant Modeling Material with resin Composition, the amount of adhesive is preferably 0.25～5 weight %, preferred especially 1～3 weight %.But all adhesives of acid cure, but but the adhesive of those acid cures of the particularly conventional mould material mixture that is used to make foundary industry all can be used as the adhesive of acid cure.Except that comprising crosslinkable resin, adhesive also can comprise other conventional ingredient, as is used to regulate the solvent of viscosity or the extender of instead of part crosslinkable resin.

Adhesive is applied on the fire-resistant Modeling Material that scribbles acid, and its form with film is distributed on the particle of fire-resistant Modeling Material by mobile mixture.

The amount of adhesive and acid is chosen as, and makes mold reach enough intensity on the one hand, makes mould material mixture reach enough processing times on the other hand.For example the processing time be 5～45 minutes be suitable.

By conventional method the fire-resistant Modeling Material that scribbles adhesive is shaped to form mold then.Mould material mixture can be introduced in the suitable mould and compacting for this reason.Institute's mold is solidified.

All furane resins that have been used for furans and do not have the baking adhesive composition all can be used as furans and do not have the baking adhesive.

There are not furane resins that baking uses in the adhesive normally precondensate or the mixture of furane resins and other monomer or precondensate at industrial furans.There is not the precondensate method manufacturing that oneself knows with itself contained in the baking adhesive at furans.

According to a preferred real scheme of revolving, furfuryl alcohol with being used in combination of urea and/or formaldehyde or urea/formaldehyde-precondensate.Formaldehyde can monomeric form uses, for example with the form of formalin solution and with its polymer as three The form of alkane or paraformaldehyde is used.Except that formaldehyde or replace formaldehyde also can use other aldehydes or ketones.The example of suitable aldehyde comprises the mixture of acetaldehyde, propionic aldehyde, butyraldehyde, methacrylaldehyde, crotonaldehyde, benzaldehyde, salicylide, cinnamic acid, glyoxal and these aldehyde.Preferred formaldehyde, and preferably use with the form of paraformaldehyde.

Can use all ketone as the ketone composition with enough high responses.Exemplary ketone comprises methyl ethyl ketone, methyl propyl ketone and acetone, preferably uses acetone.

Described aldehyde and ketone all can be used as compound separately or mix use.

Aldehyde (particularly formaldehyde) or ketone can be selected in wide region the mol ratio of furfuryl alcohol.When making furane resins, every mole aldehyde can especially use 0.4～4 mole of furfuryl alcohol, preferably uses 0.5～2 mole of furfuryl alcohol.

After for example being adjusted to the pH value greater than 4.5, furfuryl alcohol, formaldehyde and urea can be heated to boiling point and make precondensate, fall water continuous evaporation from reactant mixture this moment.Reaction time can be several hours, for example 2 hours.Under this reaction condition, in fact polymerization does not take place in furfuryl alcohol.Yet furfuryl alcohol advances in the resin with formaldehyde and urea condensation.

According to a kind of alternative method, furfuryl alcohol, formaldehyde and urea are starkly lower than 4.5 in the pH value, and the pH value as 2.0 is down through adding thermal response, and the water that produces in condensation under reduced pressure distills out.This product has relative high viscosity, therefore needs with the furfuryl alcohol dilution, to arriving desired viscosity for making adhesive.

The use also capable of being combined of these manufacture methods.

Also phenol can be added in the precondensate.For this reason, phenol can at first generate resole resin with formolite reaction under alkali condition.Can or contain the resin reaction of furyl or mix resole resin and furfuryl alcohol then.For example, this resin that contains furyl can obtain with above-mentioned method.Can use higher phenols such as resorcinol, cresols or bisphenol-A for making precondensate.The phenol in adhesive or the content of higher phenols especially are chosen as maximum 45 weight %, preferred maximum 20 weight %, preferred especially maximum 10 weight %.According to an embodiment, the content of phenol or higher phenols may be selected to be greater than 2 weight %, according to another embodiment, greater than 4 weight %.

In addition, also can use the condensation product of aldehyde and ketone, condensation product mixes with furfuryl alcohol to make adhesive then.This condensation product can react manufacturing by aldehyde and ketone under alkali condition.Preferred use formaldehyde particularly paraformaldehyde as aldehyde.The preferred acetone that uses is as ketone.Yet, also can use other aldehydes or ketones.The relative mol ratio of aldehyde and ketone is preferably 7: 1～and 1: 1, preferred 1.2: 1～3.0: 1.Condensation is preferably carried out under the pH-value is 8～11.5, preferred 9～11 alkali condition.For example suitable alkali is sodium carbonate.

There is not the amount of furfuryl alcohol contained in the baking adhesive on the one hand by making every effort to keep alap one-tenth to determine originally at furans.Improve the intensity of mold on the other hand by the furfuryl alcohol of high-load.Yet, in adhesive, containing the mold that obtains being highly brittle under the furfuryl alcohol situation of high content, this mold is difficult to processing.The content of the furfuryl alcohol in adhesive especially is chosen as 30～95 weight %, is preferably 50～90 weight %, preferred especially 60～85 weight %.The content of urea and/or formaldehyde especially is chosen as 2～70 weight % in the adhesive, preferred 5～45 weight %, preferred especially 15～30 weight %.The uncombined amount that this content both had been included in these compounds that comprise in the adhesive is also included within the amount of chemical combination in the resin.

Can add other additive in furane resins, as ethylene glycol or similar for example sugar alcohol such as D-sorbite of aliphatic polyol, it is as extender and replace the part furfuryl alcohol.If add too much extender, then under worst situation, can cause the intensity of mold to descend and reactive the reduction.Thereby the content of this extender especially is chosen as less than 25 weight % in the adhesive, preferably less than 15 weight %, especially preferably less than 10 weight %.For saving the obvious intensity that influence mold of cost and don't meeting, according to an embodiment, the content of extender is chosen as greater than 5 weight %.

This furans does not have the baking adhesive also can be moisture.Yet, because water has slowed down the solidification process of this mould material mixture and during curing water generate as product, so the content of water is preferably minimum.The content of water is especially less than 20 weight %, preferably less than 15 weight % in the adhesive.From the viewpoint of economy, the content of water is permissible greater than 5 weight % in the adhesive.

Use resole resin as phenol resin in the method for the invention.Resole resin is the mixture of hydroxymethyl phenol, and it is through methylene bridge and the combination of methylene ether bridge, and can be by aldehyde and phenol with mol ratio 1: choose＜1, that reaction obtains in the presence of catalyst such as base catalyst wantonly.Its molecular weight Mw≤10000g/mol.

The conventional all phenol that uses all is suitable for making phenol resin, and phenol is particularly preferred.Preferred use formaldehyde particularly paraformaldehyde as the aldehyde composition.Oneself has described other phenol and aldehyde in about polyurethane binder.Can consult corresponding paragraph.

Adhesive also can comprise conventional additives, for example as the silane of coupling agent.The example of suitable silane comprises amino silane, epoxy radicals silicone hydride, hydrosulphonyl silane, silicol and urea groups silane such as γ-hydroxypropyl trimethoxy silane, gamma-amino propyl trimethoxy silicane, 3-urea groups propyl-triethoxysilicane, γ-Qiu Jibingjisanjiayangjiguiwan, γ-glycidoxypropyltrime,hoxysilane, β-(3,4-epoxy radicals cyclohexyl) trimethoxy silane, N-β-(amino-ethyl)-gamma-amino propyl trimethoxy silicane.

If use this silane, then its amount in adhesive is added to 0.1～3 weight %, preferred 0.1～1 weight %.

Adhesive also can comprise other conventional ingredient such as activator or plasticizer.

Except that comprising fire-resistant Modeling Material, adhesive and optional catalyst, mould material mixture also can contain some other conventional component.Other exemplary compositions comprises iron oxide, the flax fiber through grinding, wood chip grain, carbon or clay through grinding.

Utilize conventional method that mould material mixture is shaped with the part of formation basic mode or basic mode then, and optional being cured.Then, can assemble basic mode wholly or in part, and available above-mentioned coating composition applies in whole or in part to the die cavity in the basic mode.For this reason, can use conventional method.For example, can come the applied coatings composition by dip-coating, flow coat, brushing or by spraying.

If use dip-coating method, then the optional mold that scribbles basic coating in the die cavity was immersed in the container that has been full of instant coating composition of the present invention about 2 seconds～2 minutes as application process.From coating composition, take out mold then, and unnecessary coating composition is discharged from mold.Unnecessary coating composition is discharged the required time and is depended on the outflow characteristic of used coating composition after the dip-coating from mold.

If use spraying as application process, then use commercially available pressurized tank sprayer.In this case, will be in the coating composition charged pressure jar that dilutes shape.Can coating be compressed into spray gun by the overvoltage of setting, and spray by means of the atomizer that can regulate separately therein.The condition of spraying process preferably is chosen as, and the coating composition in the adjusting spray gun and the pressure of atomizer make that the coating composition through spraying remains wet when contact mold or core, but evenly uses.

Then evaporate carrier fluid contained in coating, with the dope layer that obtains doing.Can use all conventional drying methods as drying means, as at open air drying, use air drying through dehumidifying, with microwave radiation or infrared radiation drying, dry and with similar method drying in convection furnace.

In a preferred embodiment of the invention, coated mold is at 100～250 ℃, and is dry in convection furnace under preferred 120～180 ℃.When using alcohol coating, preferably carry out drying by burning-off alcohol or alcohol mixture according to coating composition of the present invention.In this case, coated mold is additionally heated by the combustion heat.In another preferred embodiment, at the open mold of air drying through using, and without other processing.

If contain suitable curable adhesive in the coating composition, then can choose wantonly by for example dope layer being cured with the irradiation of UV line.

This coating can be used with the form of simple layer or a plurality of overlapped layers.Each layer can be identical or different on forming.For example at first can form basic coating by the commercial coating that does not contain metallic addition of the present invention.For example can use water paint or alcohol coating as basic coating.Yet, also can form all layers by coating composition according to the present invention.Yet the layer that contacts with liquid metal is thereafter always formed by coating of the present invention.If use multilayer, then can after using, carry out dry wholly or in part to each layer.

Especially comprise thickness by the coating of coating composition manufacturing and be 0.1mm at least, preferred 0.2mm at least, especially preferred 0.45mm at least, the dried layer of especially preferred 0.55mm at least.According to an embodiment, select coating layer thickness less than 1.5mm.In this case, dry layer thickness is the thickness of the coating of drying, its by coating composition by removing solvent composition substantially fully and optional carry out follow-up curing and obtain.The dry layer thickness of base coating and lid coating is especially by calculating with the wet layer thickness comb.

Can choose wantonly then and assemble this mold fully.

The invention still further relates to the application of above-mentioned mold in making foundry goods.

At first make mold for this reason.It can be discarded type mold, as mentioned above can be by refractory material such as quartz sand and adhesive manufacturing, or can be the permanent type mold, as be generally used for making pipe fitting, bearing or axle sleeve, die cavity is made lining with aforementioned coating composition.Mold has protective finish at least with on the bearing surface that liquid metal contacts, and this protective finish is isolated liquid metal and mold, and can be to the surface characteristic of foundry goods in favourable influence.At this moment liquid metal (especially being iron or ferroalloy) is imported in the mold that makes.Then make liquid metal solidification become foundry goods, then foundry goods is separated with mold.Use usual way for this reason.Under discarded type mold situation, this mold is through mechanical damage, for example by flutter failure.Under permanent type mold situation, this foundry goods is extracted out from mold with usual way.

The invention still further relates to a kind of mold with mould coating of making by above-mentioned coating.Advantageously this mold has the isolation between liquid metal and mold, has reduced the thermic load of this mold thus in casting cycle, and has increased the durability of this mold thus.As another advantage, mould coating containing metallic additive, this metallic addition can be favourable influence to the surface characteristic of foundry goods, particularly can be suppressed at and form the spot surface on the foundry goods.

Mold with lid coating of being made by coating composition of the present invention is particularly useful for making wind turbine hub hub, mortar, engine and engine components, frame and turbine, general-purpose machinery parts or press instrument.

Be described in further detail the present invention with embodiment below.

Embodiment 1

Employed in the following embodiments core cover has the composition that provides in the table 1.

Table 1: the composition of coating

Composition	Weight %
		Zirconium silicate 75 μ m	50.00
Manganese (325 order)	20.00
		Clay mineral	03.00
Synthetic resin	02.00
		Rheologic additive	00.50
Ethanol	14.50
		Isopropyl alcohol	10.00

This adhering mo(u)lding material is by being prepared as follows: add isopropyl alcohol earlier, wherein decomposed clay at least 15 minutes by using high-shear mixer.Then stir and added refractory composition, pigment, manganese and colouring agent at least 15 minutes, up to forming homogeneous mixture.Stir at last and add ethanol, rheologic additive and adhesive.

Claims (13)

1. coating composition that is used for mold and core, it comprises at least a metallic addition that contains metal or metallic compound, wherein said metal one of is selected from the 7th family that comprises metal or metallic compound or the 9th～12 family, and described metal one of is selected from the periodic table of elements in the 7th family or the 9th～12 family.

2. coating composition according to claim 1, wherein said metal one of are selected from the periodic table of elements in the 7th, 10 or 11 families.

3. coating composition according to claim 1 and 2, wherein said metal is selected from manganese, copper and mickel.

4. each described coating composition in requiring according to aforesaid right is wherein measured by metal and based on the weight of described metallic addition, the described metal that comprises in the described metallic addition or the content of metallic compound are at least 10 weight %.

5. each described coating composition in requiring according to aforesaid right, wherein based on the solid content meter of described coating composition, the content of the described metallic addition that comprises in the described coating composition is at least 10 weight %.

6. each described coating composition in requiring according to aforesaid right, wherein said metal is included in the described metallic addition with the form of ferroalloy.

7. each described coating composition in requiring according to aforesaid right, the particle mean size of wherein said metallic addition (D50) is 0.5～5000 μ m.

8. each described coating composition in requiring according to aforesaid right, wherein said coating composition comprises solvent, and described solvent to small part is made up of at least a alcohol.

9. coating composition according to Claim 8, the content of wherein said at least a alcohol accounts at least 50 weight % of described solvent.

10. method that is used to make mold, wherein

-mould material mixture that comprises at least a fire-resistant Modeling Material and adhesive is provided,

-with described mould material mixture be configured as the basic mode that comprises die cavity and

-use the face that applies the die cavity of described basic mode according to each described coating composition in the claim 1～9 at least.

11. the mold with die cavity, wherein the face of described at least die cavity is coated with each described coating among the with good grounds claim 1-9.

12. be used for the purposes of metal casting according to the mold of claim 11.

13. according to the purposes of claim 12, wherein said metal casting is iron casting or steel casting.