SE459400B - PROCEDURE FOR CASTING LIGHT METAL OBJECTIVES USING A POLYMERIZABLE BINDING AGENT - Google Patents

Description

459 400 2 10 15 20 25 30 35 Acids are often used as catalysts.

About 10 years ago, room temperature processes were introduced, which are carried out at high speed, for the production of casting cores and molds. The binder formed at these. processes, are based on urethane chemistry. Broadly speaking, binder materials The material consists of two liquid resin components. One component is a phenol-formaldehyde species. The second component is a polymeric isocyarzate. The phenolic resin and the isocyanate resin are mixed das with sand and can be used in either a "cold box" - or a "no bake" system. At the so-called the cold box system is blown the one which has been coated with the two components, into a core box. Once the sand mixture has been soaked into a core box, bring a gaseous tertiary amine to pass through the core box to achieve instantaneous curing or solidification to form of the binder. US PS 3 # 09 579 illustrates this technology.

In the no-bake-type nucleation procedure the polyisocyanate component, the phenolic resin component and a catalyst dry all with sand at the same time. The sand mixture is then poured in a core box or in a pattern. The sand mixture remains during a certain period of time. When this time period has elapsed the catalyst initiates the curing or polymerization, and the core is formed rapidly, as the binder components reacts rapidly to form a urethane binder. No bake- binder is disclosed in U.S. Pat. No. 3,676,392.

Another adhesive composition and procedure for forming a casting binder is described in U.S. Pat. No. 3,879,339 this patent describes a method in which one uses a cold box, i.e. room temperature, and gas hardening, for molding of a casting binder comprising an organic resin, which is acid curable, and an oxidizing agent. This binding component cured with sulfur dioxide gas. The combination of sulfur dioxide plus oxidizing agent leads to the formation of sulfuric acid, which acid helps harden the acid-curable organic resin. In everything It is essential that sulfuric acid is formed in situ, and the acid reacts ferments with the resin. Thus, curing of the binding is achieved the composition.

None of the casting binders described above are of such usefulness and versatility that they are considered universal or irreplaceable casting binder. Each has advantages 10 15 20 25 30 35 459 400 and disadvantages to some extent.

An object of the present invention is therefore that provide a new process for casting light metal target using a polymerizable binder based on a chemistry, which so far has not been applied to the casting area or other areas of binder use. One Particular object of the invention is to provide a method for casting using a casting binder of cold box type, which exhibits rapid curing. Another purpose is to use a cold box binder, which is useful in casting of aluminum and other light metals.

BACKGROUND OF THE INVENTION The present invention thus relates to a method process for casting light metal objects, which objects are formed using casting details, which disintegrate after casting the metal objects, which procedure is characterized by a) forming a casting part by placing on a casting ballast material advantageous a binding amount of a binder material, which essentially consists of acrylic monomer, acrylic polymer or mixtures thereof, form the ballast material into the desired casting detail and polymerizes the binder material using a free radical initiator, which comprises an organic peroxide and a catalytic agent consisting essentially of gaseous sulfur dioxide, b) heats a light metal until it melts and can cast, c) casting the song metal using the shaped casting the detail, d) allowing the cast metal to solidify, and e) breaks the casting part and removes the broken one the casting part from the cast light metal object.

In general, the present invention provides uses curable binder compositions at room temperature, which can polymerize by free radical initiation and chain extension. These binder compositions are useful for to cause materials to adhere to each other and then specifically ellt particulate solids. In particular, the invention Applicable to compositions which exhibit the ability to bind 459 400 10 15 20 25 30 35 4 sand or other ballast materials to form molds or cores for casting metals, including special aluminum and other light metals. Molds and cores produced when using these binders, superior disintegration divisibility, when used in the casting of light metals, metals cast at low casting temperatures. The hardening of _ the binder material to form the binder composition preferably takes place at ambient or room temperature and provided by a free radical initiator comprising a per- oxide and a catalytic agent. gaseous blicklig. i.e.

The catalytic agent is , and the curing is almost DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF UPPER THE FINDING The present invention is illustrated in connection with a casting binder, for which the chemistry is different from that used for position of any binder which has hitherto been rit known to be useful in the casting industry. Bindemed- is also useful as a binder or binder. in areas other than the foundry industry. The chemistry on which this binder is based, is analogous to a type of chemistry, which is until has been used in the field of coatings; see e.g.

GB PS 1,055,242; and adhesives; see e.g. various patents in the name Loctite Corporation. An anaerobically cured casting binder based on similar chemistry is described in CA PS 1,053,440. This binder hardens very slowly, and heating is required to achieve hardening. The present invention does not include any got anaerobic curing procedure but refers instead to fast the immediate instant, said catalytic agents. in IN curing at room temperature with vis- It is well known that molded bodies, i.e. cores and , is formed by sanding or other ballast terial applies a binding substance or chemical, that man moth' gives the sand the desired shape and that you allow or bring the binding substance or chemical to cure to form of a binder. The present invention can be considered as a binder, which is obtained by combining two parts. Part I is a binding substance or composition which is 10 15 20 25 30 35 459 400 polymerization and crosslinking to adhere, hold or bind the sand or other ballast material in the desired form. The second part (Part II) is a means of merisation and networking of Part I takes place. This means is referred to herein as a "free radical initiator". Such as the term "network" used in the present description, it refers to a chain construction result when a polymer is involved either by linking with another polymer or with a monomer.

The term "polymerization" includes "crosslinking" but refers to also the chain extension that takes place for monomers only.

Part I of the binder system can be described as an unsaturated one composition which is crosslinkable or polymerizable with the oldest free radical mechanism. The unsaturation is preferably present in final position or in protruding groups. Even internal unsaturation is acceptable, and polymerization occurs in combination with Part II. It is also conceivable, depending on the synthetic method of component Part I, to have a Part I component with both end sets and / or protruding unsaturation as well as internal unsaturation in the same component. It is believed that the polymerization mechanism is practical taken entirely is of the free radical type when bridging compositions (ie unsaturated polymer (s)) are involved.

When certain monomers are used as a binding composition, it is possible that part of the polymerization may take place by means of any mechanism other than a free radical. It should therefore be served, that the present description is not limited to any special polymerization mechanism without the expression "free radical mechanism" was used for simplicity and described such a mechanism is correct in virtually all cases.

However, it is understood that in addition to the free radical mechanism other mechanisms may also occur in the polymerization there are certain circumstances. Curing is accomplished during Part II, a free radical initiator, which includes a per- oxide and a catalytic agent. It has been discovered that unsaturated the reactive monomers, polymers and mixtures thereof (ie the binding composition) can be used as a binding agent. material, which instantly hardens when selecting certain catalysts. free radical initiator. The one in the monomers and the polymers recovered unsaturation are preferably of ethylenic type. For example, reactive polymers are used, which can also 459 400 10 15 20 25 30 35 6 described as oligomers or as adducts, the essentially contains vinyl or acrylic unsaturation, as a formation compositions which, upon polymerization, provide a binder for casting cores or molds of sand. Free radical initiator (Part II) mixed with the reactive polymer or monomer (Part I) and form free radicals, which polymerize the binding component. the formation of the binder. This combination of a peroxide and a catalytic agent, which agent in addition to chemical in nature can also be a form of energy, is referred to herein as a "free radical initiator".

The free radical initiator described herein can be used for effecting polymerization of Part I materials on a number way. For example, the peroxide can be mixed with the Part I material, and this mixture is homogeneously distributed on sand. When the sand has formed in the desired manner, the shaped sand can be exposed to the catalytic agent. Alternatively, the catalytic agent may is added to the Part I material and this mixture is used for to coat the sand and the coated sand is then formed on desired way. The peroxide component of the free radical initiator can therefore _after added to the shaped part , and curing by polymerization takes place.

It is also possible to divide Part I- the material in two portions. The catalytic agent can be added to one portion and the peroxide to the other portion.

When the two portions are combined, after applying it material to be bound in at least one portion, cuts polymerization. Depending on the type of catalytic agent or equipment as well as used application can this last method may not be practicable. About the binding however, the material was used to bring non-particulate matter shaped materials to staple together, this last method can be especially useful. The choice of different catalytic agents is great impact in the ways that can be used to polymerize it binding material and at the rate at which it binds hardening material. Selection of the appropriate catalytic agent does it is possible, for example, for the user of the binding material to instantly polymerize the material at room temperature. or to delay the polymerization for a certain period of time and achieve polymerization at elevated temperature. The opportunity to alternatives as regards the choice of conditions, under which it 10 15 20 25 30 35 459 400 7 the binding composition is polymerized, may be considered significant fikant.

As described above, the binding material is one polymerizable, unsaturated acrylic monomer, acrylic polymer or blended such monomer (s) and such polymer (s). As examples of materials for which monomeric compounds are suitable component Part I, a variety of monofunctional, difunctional, trifunctional and tetrafunctional acrylic ter. A representative listing of such monomers includes alkyl acrylates, hydroxyalkyl acrylates, alkoxyalkyl acrylates, cyanoalkyl acrylates, alkyl methacrylates, hydroxyalkyl methacrylates alkoxyalkyl methacrylates, cyanoalkyl methacrylates, N-alkoxy methyl acrylamides and N-alkoxymethyl methacrylamides. Difunctional la monomeric acrylates include hexanediol diacrylate and tetra- ethylene glycol diacrylate. Other useful acrylates are e.g. tri- methylolpropane triacrylate, methacrylic acid and 2-ethylhexyl methacrylate.

It is advisable to use polyfunctional acrylates, when the monomer is the only binding moiety in the binder system.

As previously mentioned, when only monomers apply used as a binding material, crosslinking may not be possible occur. Furthermore, in addition to free radicals, any mechanism mechanism cause polymerization.

Examples of unsaturated reactive polymers that have been found be particularly useful in the preparation of this casting bond. agents, are epoxy acrylate reaction products, polyester / urethane / acrylic lat reaction products, polyether acrylates and polyester acrylates.

Unsaturated polymers useful as Part I composition includes commercially available materials, such as UVITHANE 782 and 783, acrylated urethane oligomers from Thiokol and CMD 1700, an acrylated ester of an acrylic polymer and CELRAD 3701, an acrylated epoxy resin, both marketed by Celanese. Reactive polymers can be prepared in a number of ways. A preferred process for preparing the reactive polymers is that form an isocyanate end-capped prepolymer by reacting one polyhydroxy compound or polyol with a diisocyanate. Prepoly- the mer is further reacted with a hydroxyalkyl acrylate to form of an oligomer. A second method, which has been found to be means that a polyisocyanate compound is reacted, preferably a diisocyanate compound, with a hydroxyalkyl acrylate. 459 400 10 15 20 25 30 35 8 The reaction product is an "adduct" of these two materials.

Addition oligomers and adducts can be prepared simultaneously under appropriate conditions.

In addition to the reactive unsaturated polymer, a solvent agents, preferably of a reactive nature, are included and included preferably as a component of the binding material. Depend- nature of the unsaturated binding material may inert solvents can also be used. The preferred solvent is an unsaturated monomeric compound such as that described above in the enumeration of monomeric Part I materials. Consequently, The Part I material comprises a mixture of these unsaturated mono- and unsaturated polymer, which have been previously mentioned for conversion as Part I material per se. The best results are obtained when a solution of an unsaturated reactive polymer and a monomer unsaturated solvent was used. This combination seems easier be able to undergo copolymerization and crosslinking to form of a binding matrix, which is required either to bring sand or other ballast material to adhere together, so that a mold core or mold is formed, or to bind other materials terial .; As has been stated, it is appropriate that in Part I of the system using an unsaturated monomeric compound as a solvent. agents in addition to the unsaturated polymer. As described above, these monomers contain unsaturation and are crosslinkable with the polymer in addition to acting as a solvent for the unmeasured ~ tade polymers. Any of the unsaturated monomers (or combination thereof) which have been described as being reversible Part I materials per se are also useful as solution solutions. average. Ethylene unsaturation, preferably of vinyl or acrylic type, recommended. Examples of advantageous monomers, which are useful as solvents for the unsaturated polymers pentaerythritol triacrylate, trimethylolpropane triacrylate, diol diacrylate and tetraethylene glycol diacrylate, which were used as solvent for the unsaturated polymer. The amount of monomer in Part I can be from 0 and up to 100% based on the total weight of the Binding Composition Part I. , is 1,6-hexane- It is possible to use the reactive polymer as Part I material and free radical initiator without any solvent, including unsaturated monomer, is present for the unsaturated 10 15 20 25 30 35 459 400 polymers. It is also conceivable to use the unsaturated mono- more as Part I material with a free radical initiator but without the reactive polymer in order to obtain a polymerized binder. Neither of the two combinations described above preferred. As previously stated, the preferred binder is Part I system comprising a reactive unsaturated polymer dissolved in a reactive diluent, preferably a modulus numbered unsaturated solvent, and Part II comprising a free radical initiator.

The free radical initiator consists of two components. The proposed take component is essentially an organic peroxide. It is however implied that this can be used together with another substance which forms free radicals upon exposure to a catalytic agent, whereby it can be used together with the free radical polymerizable binding material Part I including unsaturated polymers, monomers and mixtures thereof described above. The peroxide level can vary within wide limits, which are to some extent dependent on the catalytic agent used.

In general, however, it can be said that from 0.5% to 2% peroxide, on the weight of the binding material (Part I), provides satisfactory binding under most conditions. Examples of preferred peroxides are t-butyl hydroperoxide, cumene hydroperoxide and methyl ethyl ketone peroxide. It is worth noting that peroxides are highly preferred over peroxides. Unsatisfactory curing has been observed using peroxide. Among- peroxides and hydroperoxides and mixtures of hydrogens roperoxides are useful.

The catalyst component of the free radical initiator is essential chemical in nature, namely gaseous sulfur dioxide.

Other chemical catalytic agents, which may have some In addition, its usefulness includes amines and NO 2. Re- again, it should be noted that a change in the catalytic can have a strong effect on the polymerization rate. Other non-chemical agents that interact with the sulfur dioxide can, however also be useful. For example, heat, at an approximate minimum temperature of 60 ° C, along with peroxide form free radicals, which contribute to the polymerization of Part I materials.

An increase in temperature tends to increase the polymerization and cause faster curing. The polymerization takes place without 459 400 10 15 20 25 30 35 10 be a chemical catalytic agent.

In preferred casting practices, the unsaturated reactive is mixed the polymer, the monomer or mixtures thereof and the peroxide component in the free radical initiator with sand in a conventional manner.

The sand mixture is then formed into the desired casting configuration by framing, blowing or other known methods of position of casting cores and molds. The shaped part expo- then for the catalyst component of the free radical initiator tower. In the preferred method of the present invention Only gaseous SO 2 was used as a catalyst in free radicals. initiator. This gas is present only in catalytic amounts as previously stated. Contact exposure time The distance between the sand mixture and the gas can be as short as half second or less, and the binder component cures at rate with the catalytic agent. When SO 2 was used as a catalyst in a cold box casting process, it is suspended in a flow of carrier gas in a known manner. The carrier gas is usually NZ. So as little as 0.5% SO2, calculated on the weight of the carrier gas, is sufficient to cause polymerization. It is also conceivable to expose the binder component to SO 2 without the presence of any carrier gas.

Part I may also contain any constituents. Eczema pelvis can additives to effect wetting and for to prevent foaming be useful. Sílaner has been found be particularly useful additives. Especially preferred are unsaturated silanes, e.g. vinyl silanes.

The advantages of the bonding composition as a cast bonding means are as follows. The decomposition, or the ability to "collapse", for the binder when used for casting aluminum minium is excellent. It has been found, that the present binding agent is easily decomposed, i.e. the shaking of an aluminum casting detail can be done while applying a minimum of external energy.

The binder also provides good strength properties. Bench or the service life of sand mixed with Part I is long. Obtained surface finishes of castings manufactured using horizontal binder and process have been found to be very good.

The production rate of cores and molds produced below use of the present binder system is high, especially when only 502 gas was used as catalyst. 459 400 11 In a foundry, in which the one described herein is used binder composition, Part I and a component of free the radical initiator, preferably the peroxide, with sand or something other suitable casting ballast material in a known manner. The sand mixture then formed into the desired casting configuration, cores or molds, on. known manner. The sand mixture is then exposed to the second the component of the free radical initiator, preferably the catalytic the agent, which is preferably sulfur dioxide gas, and polymerized of the binder material Part I takes place immediately to the of the binder of the present invention.

The present invention is further illustrated by the following examples, in which, unless otherwise indicated, all parts refers to parts by weight and all percentages refer to weight percent.

Exegqel l Gel experiments were performed on various unsaturated monomers and poly- more to determine their tendency to polymerize and the polymerization firmness. In carrying out the experiments was mixed from about 1.5 to 2 g of unsaturated monomer or polymer (ie Part I) with 0.03 g of t-butyl hydroperoxide (peroxide component) ten in the free radical initiator). This mixture was then exposed after for SOQ gas (the catalytic agent in the free radical initiator atom), either by dispersing the gas in the liquid (bubbling ) or by creating an SOQ atmosphere above the liquid (plug). The results, given below, indicate that all \ unsaturated monomers and polymers polymerize. Thus, the potential compounds listed. They enumerated compounds which showed rapid polymerization or gelation, is of greatest potential value as a casting binder to make The mold and core production are fast at sufficient speed effect using a so-called cold box. gel; Pollmerisationsfórlogp Acrylic acid Fast, on contact with S02 Ethyl acrylate Slow, on contact with SO 2 n-butyl acrylate Slow, on contact with S02 ¿ Isobutyl acrylate Slow, on contact with SO 2 α-Ethyenexylaxu-yiet fast, on contact with soz Isodekyl acrylate Fast, on contact with SO2 459 400 _ 13 Part I Polxgerisationsförlogg 2-ethoxyethyl acrylate Fast, on contact with SO 2 Ethoxyethoxyethyl acrylate Fast, on contact with SO 2 Butoxyethylalylate Fast, on contact with SO2 Hydroxyethyl allylate Rapid, on contact with SO2 lüdroxypropyl acrylate Fast, on contact with SO2 Glycidyl acrylate Fast, on contact with SO2 Dimethylaminoethyl acrylate Fast, on contact with SO2 Cyanoethyl acrylate Fast, on contact with SO2 Diacetonalzrylamide i _ methanol, 50% Fast, on contact with SO 2 Acrylamide in methanol, 50% Fast, kontakt id contact with S02 (N-methylcarbamoylox2- ethyl acrylate Fast, on contact with SO2 Methylcellosolve Alcrylate Fast, on contact with SO 2 Phenoxyethyl acrylate Fast, on contact with SO 2 Benzyl acrylate _ Fast, on contact with SO2 Ethylenglyiwlâ-krïïë-t * -phthalate Fast, on contact with S02 Helamine acrylate Fast, on contact with S02 Diethylene glycol diacylate Fast, on contact with S02 Hexanediol dialcrylate Fast, on contact with S02 Butanediol diacrylate Fast, on contact with S02 Triethylene glycol diacrylate Fast, on contact with SO2 Tetraethylerzglycol diacry- lat Fast, when in contact with S02 Neopentyl glycol diacrylate Fast, on contact with S0 1,1-butylene glycol diacrylic lat Fast, when in contact with S02 Trimethylolpropantri- almylate Fast, on contact with S02 Pentaerythritol triaczwlat Fast, on contact with S02 Methacrylic acid Fast, on contact with SO2 Methyl methacrylate Slow, when bubbling with SO2 E-ethylheegul methacrylate Slow, on bubbling with SO 2 Hydroxypropyl methacrylate Fast, on contact with SO 2 Glycidyl methacylate Fast, on contact with SO2 459 400 _ 13 'Part I golmerisationsförlogp Dimethylaminoethylmethane curled Fast, on contact with S02 Ethylene glycol dimethyl wuallate Fast, on contact with SO2 Trimethylolpropantri- methacrylate Fast, on contact with SO2 Acrylated urethane here- _ lead from glycerol 65% fast, vidxoncaxr with SO2 1 nnx / msol-lo N-methylolalcylamide i water 60% Fast, on contact with SO2 N- (isobutoxymethyl] - acrylamide 1 methanol 50% Fast, on contact with SO 2 npom-yl R- le-narts áshell) acrylated epoxy Slow, on contact with SO2 0% 1 acetone _ UvImANE 783 (Tnioxol / Chem.Div.) Acrylated Fast, on contact with SO 2 urethanol oligomer AROPOL 7200 (ASHLAND) unsaturated polyester resin Slow, on contact with SO2 and acetone RI con 157 (Colorado Specialty Chemical) et unsaturated hydrocarbon resin in Slow, on contact with SO2 acetone 50% Hydroxy PBG-2000 (he co.) an unsatisfied hydrocarbon resin 1 acetone Slow, on contact with SO 2 50% Example 2 An unsaturated polymer was prepared by reaction between the equivalent of 1 mole of pentanediol and the equivalent of 4 moles hydroxyethyl acrylate with the equivalent of 5.0 moles of toluene diisocyanate nat. Dibutyltin dilaurate was used to catalyze the reaction.

Based on the solids content, 0.14% catalyst was used. Hydro- quinone monoethyl ether was used as inhibitor. The operation was performed in a reaction medium (solvent) consisting of ethylhexyl acrylate and hydroxyethyl acrylate. When carrying out the reaction a mixture of TDI and solvent was charged to a reaction medium. Container. Pentanediol is added to this mixture followed by addition of hydroxyethyl acrylate. When the addition of hydroxyethyl acrylate is É completed, catalyst is added. The reaction is carried out under I 459 400 _ 14 air blowing. The reaction is allowed to proceed at 40 to 45 ° C in 2.1 hours, after which the temperature is raised to 80-35 ° C, and the reaction is continued for 4.3 hours, after which 0.03% inhibitor is added. is added and the reaction is continued for 1/2 hour. The product let cool. The product was tested for non-volatile _ material, whereby the value 593% was obtained. This corresponds to a theoretical amount of 60% non-volatile material. Product viscosity was 6.0 st. 20 g of the unsaturated polymer were then mixed with 1.6 g of acrylic acid, 10.7 g of diethylene glycol diacrylate, 9.9 g of tri- methylolpropane trimethacrylate and 2.0 g of vinylsilane. Acrylic acid, di- ethylene glycol diacylate and trimethylolpropane triacrylate are unsaturated monomers. This solution of unsaturated polymer and unsaturated monomers Part I is called Part I. 1 g of t-butyl hydroperoxide, the peroxide component in the Iriradilcal initiator, was added to the solution of unsaturated polymer and unsaturated monomers.

Wedron SOIO sand (washed and dried fine-grained silica sand, AFSGFN 66) was placed in a suitable mixer.

Part I and the peroxide component of the free radical initiator were mixed with the sand until a homogeneous distribution was obtained. The level of Part I plus peroxide is 2% based on the weight of the sand.

The sand mixture was blown into a conventional core cavity or box for the production of standardized tensile strengths briquettes in the form of test cores, which are referred to as The dog bone test jaws were hardened by the was exposed to the catalytic component 1 free radical initiator tower. The catalytic component consists of gaseous sulfur dioxide. the cores were exposed to the SO2 catalyst in approx. 1 1/2 seconds (gas time), and the catalyst was removed by blowing with nitrogen for 15 seconds, and the core was removed from boxen. The tensile strength values for the core expressed in MPa were 1.54 outside the box and 1.41 after 3 hours and 1.57 after 24 hours.

"HundbeN cores similar to those described above was used in scaling studies with aluminum casting details. Seven tensile briquettes (dog bones) were arranged in a mold. For- but contained a gate system. The shape is such that it provides castings with a metal thickness of about 6.4 mm on all sides 459 400 15 dor. 1-m opening at one end of the casting part is arranged for removal. removal of the core from the casting part. Molten aluminum with a temperature temperature of about 70 ° C produced from alumnumnaä nänaes 1 for- but. After cooling for about 1 hour, the aluminum casting parts were removed out through the gate system and was removed from the mold for cause.

The scalding attempts are performed in such a way that one places a casting detail in a 3.8 l container. The container is placed on a shaking mechanism and shake for 5 minutes. The importance of the sand core removed from the casting part in this way the initial weight of the sand core, and the percentage the shaking is calculated. Remaining sand in the casting part after it the shaking described above is removed by scraping and weighed also. The sand core, bound with the binder described above, was found to have a scaling-out value of 100. It should be observed that the exclusion test described above is non-existent standard test. We do not know of any standard test for measurement of this property. The test used is well useful to one should get an idea of the decomposition of a binding means and in order to be able to compare relative decomposition between binders. The stated percentages show one some degree of variation but are reliable indicators. 459 400 16 gggmpeï 3 * "“ sann wearon 5010 v1a 23: 111 26 ° c PART 1 a) unsaturated monomer b) unsaturated polymer unsaturated polymer synthesis 1) polyisocyanate, 1 molar equivalent polyol, in molar equivalent acrylate, 1 molar equivalent iv) catalyst v) inhibitor vii) solvent in $ ii) 111) v111) temp / tia ° c / tim. 11) viscosity, st X) $ non volatile mtrl actually theoretically c) additives 1 5 Fr1rad1ka11n1: 1aror ° (ne1 II) a) peroxide component b) catalytic component Gastid, sec.

Blowing time, sec.

Tensile strength, MPa outside box 3 tim. 24 tim.

Binder level (Part I + peroxide component) Metal casting detail Shake out. $ Acrylic acid 1.6 5, diethylene glycine carbon diacrylate 10.7 5, trimethyl- lolpropane trimethacrylate 9.9 g.

Synthesized as described below 20 3. ' TDI h Glycerol - 1 Hydroxyethyl acrylate, 5 Dibutyltin dilaurate, 0.14% Hydroquinone monomethyl ether Ethyl hexyl acrylate and hydroxy ethyl acrylate, 40% enough to 45: 1 2.15 hrs. then 80 to 85 1 4.8 hrs. 16.0 63.9 60.0 Vinylsilane - 2.0 2.2% t-butyl hydroperoxide S02 gas 0.5 15 with H2 1.2§ 1.50 1.61 2% Aluminum 100 459 400 17 Example Sand PART I a) unsaturated monomer b) unsaturated polymer unsaturated polymer showed i) polyisocyanate, 1 molar equivalent polyol, in mol- equivalent acrylate, i molar equivalent catalyst 11) 111) iv) V) vii) inhibitor solvent in v111) temp /: ia ° c / hr. viscosity % not volatile mtrl actually theoretically c) additives in 3 Free radical initiator (Part II) a) peroxide component ix) X) b) catalytic nent Gastid, sec.

Blowing time, sec.

Tensile strength, MPa outside box } tim. 24 tim. 48 tim. 4 5 Acrylic acid 1.6 3. a1- ayarox1ecy1acry1 =: ethylene glycol diacrylate 2.2 5, dicyclo- 10.7 3, trimethylol-pentenyl acrylate propane triacrylate 9.9 5 20.8 3 (N-methyl- carbamoyloxy) ethyl1- acrylate 17.3 g Synthesized as written below, 20 g TDI,} o11n ao-265a), 1 °) polyoxypropylene glycol Hydroxietylakxwlat, 11 Dibutyltin dilaurate, 0.14% Hydroquinone monomethyl ether Ethyl hexyl acrylate and hydroxyethyl acrylate, enough to 452 1 2.1 and 80 to 85 'at 4.75 4.2 59.2 60.0 Vinylsilane 2.0 5 11}% cumene hydroperoxide 2.4% t-butyl hydro- peroxide SO2 gas SO2 gas 0.5 1 15 with N2 15 with N2 , 10 I 1 0.17 ï 1.60 3 cont. : 459 400 - 18 Example 4 5 Binder level Part I + eroxide component 2% 2% Metal casting detail Aluminum Shake out. $ 100 Example 6 7 Sand '“Hadron 5010 Hedren 5010 PART I a) unsaturated monomer Pentaerythritol triacrylic acid 7.2 g, acrylate 40 g diethylene glycol acrylate 21.4 3, trimethylolpropane- b) unsaturated polymer showed 1) polyisocyanate, 1 molar equivalent ii) polyol, in mol- equivalent iii) acrylate, 1 molar equivalent iv) catalyst v) inhibitor vii) solvents 1 5 vili) 8e7p / time C tim. ix) viscosity x)% non-volatile tigt mtrl actually theoretically c) additive 1 g Free radical initiator (Part n) a) peroxide component 2,45 t-butylhydro- peroxide b) catalytic ponent Gastid, sec. 0.5 Inhalation time, sec. 15 S02 gas cont. triacrylate 13 5 2.4% t-butylhydro- peroxide S02 gas 1 10 459 400 Example Draghállf., MPa outside box 3 tim. 24 tim.

Binder level (Part I + peroxide- component) Metal casting detail Shake out. $ 0.33 7 0.90 Example Sand PART (I) a) unsaturated monomer b) unsaturated polymer i) polyisocyanate 1 molar equivalent ii) polyol, 1 mol- equivalent iii) acrylate, in mol- equivalent iv) catalyst v) inhibitor vii) solvents 1 $ v111) amp / time SQ / tim. 11) viscosity x)% non-volatile tigt mtrl actually theoretically c) additive 1 g cont. 8 Wedron 5010 Synthesized as written below, ÄO g TDI, 3 Olin 20-265, 1 Hydroxyethyl acrylate, 4 Dibutyltin dilaurate, 0.14% Eydroquinone monomethyl- ether 0.07% Pentoxon (9§, 7) hydroxyethyl acrylate 35% no °: 111 h5 ° 1 2 tim. d "after O 20: 111 85 1 h ïuxocropisx after 5 days 6, l so Vinylsilane A-172 2.0 g acrylic acid 1.6 g 9 Port Crescent Acrylic acid 3.2 g, diethylene glycol acrylate 21.4 3, trimethylolpropane- trimethacrylate 19.8 s Same as Ex. 4 40 g.

Viñylsilan 459 400 a) unsaturated monomer b) unsaturated polymer unsaturated polymer showed 1) polyisocyanate molar equivalent 11) polyol, 1 mol- equivalent iii) acrylate, 1 mol- equivalent iv) catalyst v) inhibitor vii) solvents 1 cont.

Acrylic acid 1.6 5, trimethylolpropantri- acrylate 9.9 g Synthesized as written below, 20 5 TDI, 3-5 G1ycero1-diethylene- glycol mixture ïlzl), 1 Hydroxyethyl acrylate 4.5 Dibutyltin dilaurate 0.14% Hydroclonon-monomethyl- ether 0.07% Ethyl hexyl acrylate + hydroxyethyl acrylate (= 6) 40% 20 šzemoel 8 9 Free radical initiator (Part II) a) peroxide component (90%) t-butyl hydro-t-butyl peracetate peroxide 2.25 (6 g) b): analytical zum- soa-gas heat u5o ° 1 ponent 90 sec.

Gastid, sec. 0.5 Inhalation time, sec. 15 with N2 Draft. , MPa outside box 0.37 0.52 3 sim. 0.64 24 tim. cold resistance 1.07 1.10 Binder level (Part I + peroxia- 2% 2% component) Metal casting detail Shake out. $ Example 10 11 Sand Wedron 5010 Wedron 5010 PART I Same as Ex. 10 459 400 _ 21 Éšegel 10 11 un) ¿emp /: 1a no uu 45 ° 1 2 um.

C / tim. then o 80 to 85 in 11.8 to. ix) viscosity S1'- x) f non-volatile tigt mtrl in fact 59.9 theoretically 60, O (e) additives in 5 Free radical initiator (De1 II) a) peroxide component Vinylsilane A-1? 2, 2 31801 10 10.7 Low-butyl hydroperoxide 2, b) catalytic com- SO2 gas 1/2 S0 gas in N2 ponent carrier Gastid, sec. 0.5 1/2 Inhalation time, sec. 15 with Na gas None Traction, MP8. outside box 1.57 0.48 ~ j tim. 1, 57 0.834 i 24 tim. 1.77 1.54 _ Bznaemedelsrnva i (Part I + peroxide- 2% 1.5 i component) Metal casting detail Aluminum Ubskaim. ß 100 Exenmel 12 Sand Hadron 5010 PART I a) unsaturated monomer Acrylic acid 1.6 g, diethylene glycol 5.149, trime tylolpropane triacrylate 9, 9 b) unsaturated polymer Synthesized as described below, 20 g unsaturated polymer showed i) polyisocyanate 1! molar equivalent ii) polyol and mol- Glycerin 1 equivalent. iii) acrylate, in mol- Hydroxyethyl acrylate equivalent " iv) Catalyst Dibutyltin dilaurate 0.11; cont. 459 400 Exemgel v) inlubitor v11) solvent in S v111): amp / ua ° c / n1m. 1 :) viscosity, s: x) in non-volatile mtrl actually theoretically c) additives in g Free radical initiator (Part II) a) peroxide component b) catalytic component 22 12 Hydroquinone monomethyl ether 0.03 Hešylisoamylketon, 111801 10 (65:35) 35 40: in 45 ° 1 1.75 um 80 nu 85 ° 1 4.5 umf 10 then 64.1 65 Vinylsilane 2.0, Hisol 10 5.3 2,2 $ t-butyl hydroperoxide - 70 1% SO 2 gas in Ne carrier gas Gastid, sec. 20 Blowing time, sec. No nragnållf., ma outside box 1.50 3 tim. 1.08 214 tim. 1.61 Binder level (Part I + peroxide component) 1.5 Metal casting detail Aluminum Utskalcrx. and 100 Exegel 13 Sand Wedron 5010 PART I a) unsaturated monomer Acrylic acid 1.6 g, diethylene glycol 5.49, trimethylolpropantrialaï- lat 9.9 b) unsaturated polymer Synthesized as described below, 20 g unsaturated polymer showed i) polyisocyazmt 4 molar equivalent 11) polyol, in mol- Glycerol - 1 equivalent iii) acrylate, 1 mol-hydroxyethyl acrylate equivalent iv) catalyst cont.

Dibutyltçnndilaurat 0, 14 10 459 400 Example 13 v) inhibitor Hydroquinone monomethyl ether 0.0) V11) solvent 1% Methyl isoamyl ketone, H1Sol 10 (65:35) 35% no 45 ° 1 1.75 un. then vili) 1; / ua ° c / 1; 1m. amp 80: in 85 ° 1 4.5 un. ix) viscosity, St 10 x) 5 non-volatile mtrl in fact 64, 1 theoretically 65 e) additives 1 8 Vï fi ïlsil fi n 2.0 H1 sol 1o 5, 3 Free radical initiator (Part n) a) peroxide component 2.2% t-butyl hydroperoxide - 70 b) catalytic component SO2 gas Gastid, sec. 0.5 Inhalation time, sec. 15 with air Tensile strength, MPa outside box 1.22 3 un. o, 66 24 tim. 1.0} Binder level (Part I + peroxide component) 1.5 Metal casting detail Aluminum Utsxaim. of 100 Particularly preferred embodiments of the appended patents requirements defined procedures can be summarized as follows: In the process of forming casting parts, the ballast material is the material is preferably sand. In the same process, the catalyst the chemical substance is essentially of a chemical nature, namely gaseous well dioxide. The catalytic agent is suitably suspended in a gas and exposed to the binder material for at least 0.5 seconds. there. The catalytic agent may further be elevated temperature of at least about SOOC.

In the process according to the invention it applies that binder the material may comprise a mixture in which the acrylic monomer is mixed with at least one other ethylenically unsaturated monomer. Furthermore, can

Claims (9)

The binder material comprises at least polymer in addition to the acrylic monomer. unsaturated polymer in binders with at least one ethylenically unsaturated mo ethylenically unsaturated polymer. gomer or an adduct. Conversely, the ethylenic composition may be mixed number or at least one other acrylic polymer may e.g. In the process for forming casting parts, it further holds that the amount of binder material is preferably up to 10% based on the weight of the aggregate material, preferably sand. In the process of the invention, the acrylic monomer in the binder material is preferably mixed with at least one other ethylenically unsaturated monomer or at least one ethylenically unsaturated polymer. Conversely, in the invention, the binder material preferably comprises a mixture in which the acrylic polymer is blended with at least one other ethylenically unsaturated polymer or ethylenically unsaturated monomer. In the processes it applies that the acrylic polymer e.g. may be an oligomer or an adduct. In the process for casting light metal objects, the above-mentioned preferred embodiments also occur there, i.e. in the shaping of the casting part. PATENT REQUIREMENTS A method for casting light metal articles, which articles are formed using casting details which are disassembled after casting the metal articles by: characterizing) forming a casting part by distributing on a casting ballast material a binding amount of a binder material, which consists essentially of acrylic monomer, acrylic polymer or mixtures thereof, forms the aggregate to the desired casting detail and polymerizes the binder material by means of a free radical initiator which comprises an organic peroxide and a catalytic agent consisting essentially of gaseous sulfur dioxide, 459. b) heats a light metal until it melts and can be cast, c) casts the light metal using the molded casting part, d) allows the cast metal to solidify, and e) decomposes the casting part and removes the decomposed casting part from the cast light metal article. 2. A method according to claim 1, characterized in that the forming under point a) is carried out with a binder material, which comprises said acrylic monomer and at least one ethylenically unsaturated polymer. 3. A method according to claim 1, characterized in that the forming under point a) is carried out with a binder material comprising said acrylic monomer and at least one other ethylenically unsaturated monomer. Process according to one of the preceding claims, characterized in that the catalytic agent is gaseous sulfur dioxide. A process according to any one of claims 1 and 4, characterized in that the acrylic polymer is an oligomer or an adduct. Process according to any one of the preceding claims, characterized in that the acrylic monomer comprises a polyfunctional acrylate. Process according to one of the preceding claims, characterized in that the acrylic monomer is selected from the group consisting of alkyl acrylates, hydroxyalkyl acrylates, alkoxyalkyl acrylates, cyanoalkyl acrylates, alkyl methacrylates, cyanoalkyl methacrylates, N-alkoxymethylacrylamides, N-alkoxymethylacrylacetylacetrylacetylethylacetrylacetylethylacetrylacetylethylacetylethiolethacrylateacrylateacrylateacrylateacrylateacrylate , methacrylic acid, 2-ethyl-hexyl methacrylate or mixtures thereof. Process according to Claim 7, characterized in that the acrylic monomer is selected from the group consisting of pentaerythritol triacrylate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, tetraethylene glycol diacrylate or mixtures thereof. 9. A method according to any one of the preceding claims, characterized in that the ballast material is sand.