Radical polymerization

(54) NAME Procedure for bonding two materials using a polymerizable binder (56) PUBLICATIONS CITED: --- (57) SUMMARY:

ALLF 138 8 122 AA

A binder is formed by polymerization or curing of a binding material or binding composition, an unsaturated polymer or unsaturated monomer or mixtures thereof (polymer solution), wherein at least a portion of the unsaturated Kr is ethylene, preferably of the vinyl or acrylic type, by free carbon polymerization. This free radical polymerization is accomplished by contacting the unsaturated binding material with a free radical catalyst including a peroxide and catalytic agent. In a preferred embodiment, the binding material is a solution of an ethylenically unsaturated polymer in a solvent of unsaturated monomeric compound or monomeric compounds in which vinyl or acrylic saturation is present. The binder is formed by polymerization, which occurs when the unsaturated monomer, polymer or polymer solution is exposed to the free calcium chloride. As the unsaturated monomer, polymer or polymer solution is subjected to the initiator, free radicals begin to form, and then the binder composite is polymerized to form the binder. This binder was found to be particularly suitable as a cold box type cast binder, where a rapid gas curing performed at room temperature was used. The gas, which is preferably sulfur dioxide, acts as a catalytic agent for the free radical catalyst. Cores made using this binder are particularly useful in casting aluminum and other light metals, since the binder is easily decomposed after casting these metals, meaning that the core can be completely shaken without the application of external energy. The binder Kr is also useful for making cores, which are used in casting Iron.

The numbers in brackets indicate the international identification code. INID code. Letters in clamps indicate international document code.

459 256 description of the prior art

Many different types of bonding or binder materials have found use in the manufacture of cast cores and molds. As it hardens, the binder material will impart various desirable properties to the core and molds. Examples of such¹⁰ Such properties are abrasion resistance, moisture resistance as well as breakability or shaking ability. In core manufacturing or mold manufacturing, high production is also a pursued goal.

The modern core manufacturing and mold manufacturing technology began with the use of unsaturated drying oils derived from natural products as binding materials. Linseed oil is the prime example of a drying oil. When exposed to air, linseed oil and other unsaturated oils undergo oxidatively initiated poly₂θ merizations, resulting in the formation of solid, strongly cross-linked structures. Polymer! This can be accelerated by heat or by chemical methods. These binding materials are known in the industry as nuclear oils. When forming a core, the oil is mixed with sand, and the sand mixture is configurated by a core or mold. Curing is achieved by heating or aging the core or mold for a long period of time. Core oil binders may contain, in addition to the oil component, other components, such as oil-derived esters, unsaturated hydrocarbon resins and solvents. Nuclear oil-based processes for molding mold bodies, such as molds and cores, have been known for 50 to 60 years.

Processes faster than the above-mentioned core oil processes were introduced 25 to 50 years ago. These processes require hardening of the binder material. These so-called hot box35 core processes are based on a thermosetting resin composition. Chemically, these thermosetting resins include phenol-formaldehyde resins, urea-formaldehyde resins and fur-furyl alcohol-formaldehyde resins. In addition to mem using heat to cure or polymerize these binder materials prior to insertion

459 256 acids are often supplied as catalysts.

About 10 years ago, room temperature processes, which are carried out at high speed, were introduced to produce cast cores and molds. The binder formed in these processes is based on urethane chemistry. Broadly speaking, the binder material consists of two liquid resin components. One component is a phenol-formaldehyde resin. The second component is a polymeric isocyanate. The phenolic resin and isocyanate resin are mixed with sand and can be used in either a cold box or a no bake system. In the so-called cold box system, the sand, which has been coated with the two components, is blown into a comb box. Once the sand mixture has been softened into a core box, a gaseous tertiary amine is passed through the core box to provide instant cure or solidification to form the binder. US PS 5,409,579 illustrates this technology.

In the no-bake type nuclear preparation procedure, the polyisocyanate component, the phenolic resin component and a catalyst are all mixed with sand simultaneously. The sand mixture is then poured into a core box or into a pattern. The sand mixture remains liquid for a certain period of time. When this time period has elapsed, the catalyst initiates the curing or polymerization, and the core is formed rapidly, since the binder components react rapidly to form a urethane binder. No bake binder is disclosed in US PS 5,676,392.

A further binder composition and procedure for forming a casting binder are described in US PS 3,879,559. This patent describes a method using a cold box, i.e. room temperature, and gas cure, to form a casting binder comprising an acid-curable organic resin and an oxidizing agent. This binding component is cured with sulfur dioxide gas. The combination of sulfur dioxide plus oxidizing agent leads to the formation of sulfuric acid, which acid helps to cure the acid curable organic resin. In essence, sulfuric acid is formed in situ, and the acid reacts with the resin. Thus, curing of the binding composition is accomplished.

None of the casting adhesives described above is of such utility and versatility that they are considered universal or irreplaceable casting adhesives. Each has advantages f

459 256 and disadvantages to some extent.

An object of the present invention has therefore been to provide a new binder based on a chemistry which has not hitherto been applied to the casting area or other areas affecting binder use. A particular object of the invention has been to provide a cold box type binder which exhibits rapid curing. Another object has been to provide a cold box binder which is useful in casting aluminum and other light metals. In connection therewith, however, a process has been developed which relates to the bonding of at least two materials, viz. the invention is not limited to the casting area, although for the sake of simplicity it will be illustrated below in connection therewith.

¹⁵ BACKGROUND OF THE INVENTION

Thus, the present invention relates to a method of bonding at least two materials, characterized in that a) distributing at least one of said materials a binding amount of a binder material consisting essentially of acrylic monomer, acrylic polymer or mixtures thereof, b ) contacts the materials to be bonded with each other, and c) polymerizes the binder material with the aid of a free radical initiator; which comprises an organic peroxide and a catalytic agent consisting essentially of gaseous sulfur dioxide.

In general, the present invention utilizes curable binder compositions which can polymerize by free radical initiation and chain elongation. These binder compositions are useful for adhering materials to each other and especially particulate solids. In particular, the invention is applicable to compositions which exhibit the ability to bond sand or other ballast materials to form molds or cores for casting metals, including especially aluminum and other light metals. Molds and cores made using these binders exhibit superior decomposition when used in casting light metals, ie. metals cast at low casting temperatures. The curing of the binder material to form the binder composition preferably takes place

459 256 at ambient or room temperature and is provided by a free radical initiator comprising a peroxide and a catalytic agent. The catalytic agent is substantially gaseous, and the cure is almost instantaneous.

DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION

The present invention is illustrated in connection with a casting binder, for which the chemistry is different from that used for the preparation of any binder which has heretofore been known to be useful in the casting industry. The binder is also useful as a binder or bonding agent in areas other than the casting industry. The chemistry on which this binder is based is analogous to a type of chemistry which has heretofore been used in the field of coatings; see for example GB PS 1,055,242; and adhesives; see for example various patents in the name of Loctite Corporation. An anaerobic cured casting binder based on similar chemistry is described in CA PS 1 053 440. This binder cures very slowly and heating is required to effect cure. The present invention does not include any anaerobic curing process, but instead relates to rapid, almost instantaneous curing at room temperature with certain catalytic agents.

It is well known that mold bodies, i.e. cores and molds, are formed by applying a binding substance or chemical to sand or any other ballast material, imparting the desired shape to the sand and allowing or allowing the binding substance or chemical to harden to form a binder. The present invention can be considered as a binder, which is obtained by joining two parts. Part I is a binding substance or composition which undergoes polymerization and crosslinking to adhere, retain or bind the sand or other ballast material in the desired form. The second part (Part II) is an agent that allows polymerization and cross-linking of Part I to take place. This agent is referred to herein as a free radical initiator. As the term crosslink is used in the present specification, it refers to a chain structure that results when a polymer is involved either by

459 256 linkage with another polymer or with a monomer. The term polymerization includes crosslinking but also refers to the chain extension that occurs for monomers only.

Part I of the binder system can be described as an unsaturated composition which is cross-linkable or polymerizable by free radical mechanism. The unsaturation is preferably present in 1 end position or 1 projecting groups. Internal unsaturation is also acceptable, and polymerization occurs when combined with Part II. It is also conceivable, depending on the mode of synthesis of the Part I component, to have a Part I component with both end-set and / or protrusion unsaturation as well as internal unsaturation in the same component. It is believed that the polymerization mechanism is practically entirely free-radical type when bridging compositions (i.e., 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 some other mechanism than a free radical. Therefore, it should be noted that the present description is not limited to any particular polymerization mechanism without the expression^wfree-radius mechanism is used for simplicity and correctly describes such a mechanism in virtually all cases. However, it is to be understood that in addition to the synthetic calcium mechanism other mechanisms may also occur in the polymerization under certain circumstances. Curing is accomplished using Part II, a free radical initiator, which includes a peroxide and a catalytic agent. It has been discovered that unsaturated reactive monomers, polymers and mixtures thereof (i.e. the binding composition) can be used as a binding material which instantaneously cures when selecting certain catalytic agents for the free radical initiator. The unsaturation found in the monomers and polymers is preferably ethylene-type. For example, reactive polymers are used, which can also be described as oligomers or as adducts, essentially containing vinyl or acrylic unsaturation, as binding compositions which, upon polymerization, provide a binder for casting cores or molds of sand. The free radical initiator (Part II) is mixed with the reactive polymer or monomer (Part I) to form free radicals which polymerize the binding composition to form

459 256 binder. This combination of a peroxide and a catalytic agent, which in addition to being chemical in nature also, but to a minor extent, can. be a form of energy, referred to herein as a free radical initiator. "

The free radical initiator described herein can be used to effect polymerization of Part I materials in a number of ways. For example, the peroxide can be mixed with the Part I material, and this mixture is distributed homogeneously on sand. When the sand has been formed in the desired manner, the shaped sand can be exposed to¹⁰ the catalytic agent. Alternatively, the catalytic agent may be added to the Part I material and this mixture used to coat the sand and the coated sand then formed in the desired manner. The peroxide component of the free radical initiator can then be added to the molded detail, and curing through polymerization occurs. It is also possible to divide the Part I material into two portions. The catalytic agent may be added to one portion and the peroxide to the other portion. When the two portions are combined, after application of the material to be bonded to at least one portion, polymerization occurs. Depending on the type of catalytic agent or equipment and application used, this latter method may not be practicable. However, if the bonding material is used to bond non-particulate materials, this latter method may be particularly useful. Selection of various catalytic agents has a major impact on the ways that can be used to polymerize the binding material and on the rate at which the binding material cures. Selection of a suitable catalytic agent, for example, allows the user of the binding material to instantaneously polymerize the material at room temperature or to delay the polymerization time for a certain time and finally achieve polymerization at elevated temperature. The possibility of alternatives in terms of choice of conditions in which the binding composition is polymerized may be considered significant.

As described above, the binding material is a polymerizable, unsaturated acrylic monomer, acrylic polymer or mixture of such monomer (s) and polymer (s). As examples of materials which are suitable monomeric compounds for the component

459 256

Part I may be mentioned a variety of monofunctional, difunctional, trifunctional and tetrafunctional acrylates. Representative enumeration of such monomers include alkyl acrylates, hydroxyalkyl acrylates, alkoxyalkyl acrylates, oyanoalkyl acrylates, alkyl methacrylates, hydroxyalkyl methacrylates, alkoxyalkyl methacrylates, cyanoalkyl methacrylates, N-alkoxymethyl acrylamides and N Difunctional nonomeric acrylates include hexanediol dacrylate and tetraethylene glycol diacrylate. Other useful acrylates are e.g. trimethylol propane triacrylate, methacrylic acid and 2-ethylhexyl methacrylate. It is advisable to use polyfunctional acrylates when the monomer is the only binding unit in the binder system. As previously mentioned, when monomers are used only as binding materials, cross-linking may not occur. Furthermore, other mechanism besides free radical mechanism may cause polymerization.

Examples of unsaturated reactive polymers which have been found to be particularly useful in the preparation of this casting binder are epoxacrylate reaction products, polyester / urethane / acrylate reaction products, polyether acrylates and polyester acrylates. Unsaturated polymers useful as Part I compositions include commercially available materials such as UVITHANE 782 and 783, acrylic urethanol oligomers from Thlokol and CMD 1700, an acrylic ester of an acrylic polyiner, and CELRAD 37θ1, 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 to form an isocyanate end-terminated prepolymer by reacting a polyhydroxy compound or polyol with a diisocyanate. The prepolymer is further reacted with a hydroxyalkyl acrylate to form an oligomer. A second method, which has been found to be advantageous, involves reacting a polyisocyanate compound, preferably enidiisocyanate compound, with a hydroxyalkyl acrylate. The reaction product is an "adduct" of these two materials. Addition oligomers and adducts can be prepared simultaneously under suitable conditions.

In addition to the reactive unsaturated polymer, a solvent, preferably of a reactive nature, can be included and included

459 256 preferably stitch a component of the binding material. Depending on the nature of the unsaturated binding material, 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. Accordingly, the Part I material may comprise a mixture of these unsaturated monomers and unsaturated polymer which have been previously referred to for use as Part I materials themselves. The best results are obtained when a solution of an unsaturated reactive polymer and a monomeric unsaturated solvent is used. This combination seems to be more easily able to undergo copolymerization and crosslinking to form a binding matrix required either to bring sand or other ballast materials together to form a cast core or mold, or to bind other¹⁵ material.

As indicated, in Part I of the binder system, it is convenient to use an unsaturated monomeric compound as a solvent in addition to the unsaturated polymer. As described above, these monomers contain unsaturation and are crosslinkable to the polymer in addition to acting as a solvent for the unsaturated polymer. Any of the unsaturated monomers (or combination thereof) described as being useful Part I materials per se are also useful as solvents. Ethnic unsaturation, preferably of the vinyl or acrylic type, is recommended. Examples of advantageous monomers which are useful as solvents for the unsaturated polymers are pentaerythritol triacrylate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate and tetraethylene glycol diacrylate used as the solvent for the unsaturated polymer. The amount of monomer in Part I can be from 0 up to 100% based on the total weight of the binding composition Part I.

It is possible to use the reactive polymer as

Part I material and the free radical initiator without any solvent, including unsaturated monomer, are present for the unsaturated polymer. It is also conceivable to use the unsaturated monomer as Part I material with a free radical initiator but without the reactive polymer in order to obtain a polymerized binder. Neither of the above two combinations is preferred.

459 256

As previously stated, the preferred binder system Part I comprising a reactive unsaturated polymer is dissolved in a reactive diluent, preferably a monomeric unsaturated solvent, and Part II comprising a free radical initiator.

The free radical initiator consists of two components. The first component is essentially an organic peroxide. However, it is to be understood that it can be used in conjunction 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 comprising unsaturated polymers, monomers and mixtures thereof described above. The peroxide level can vary widely, which is to some extent dependent on the catalytic agent used. Generally, however, it can be said that from 0.5% to 2% peroxide, based on the weight of the binding material (Part I), provides satisfactory bonding under most conditions. Examples of preferred peroxides are t-butyl hydroperoxide, cumene hydroperoxide and methyl ethyl ketone peroxide. It is worth noting that hydroperoxides are highly preferred over peroxides. Unsatisfactory curing has been observed with the use of peroxide. Mixtures of peroxides and hydroperoxides as well as mixtures of hydroperoxides are useful.

The catalyst component of the free radical initiator is essentially chemical in nature, namely sulfur dioxide in gaseous form. Other chemical catalytic agents which may be of some practical utility in addition include amines and X Again, it should be noted that a change in the catalytic agent can have a significant effect on the rate of polymerization. However, other non-chemical agents that interact with the sulfur dioxide may also be useful. For example, at an approximate minimum temperature of 60 ° C, together with peroxide, heat can form free radicals which help to polymerize the Part I materials. An increase in temperature tends to increase polymerization and cause faster curing. The polymerization takes place without the presence of a chemical catalytic agent.

In preferred casting practice, the unsaturated reactive polymer, monomer or mixtures thereof and the peroxide component of the free radical initiator are mixed with sand in a conventional manner. The sand mixture is then formed into the desired mold configuration

459 256 ίο by framing, blowing or other known methods for making casting cores and molds. The shaped part is then exposed to the catalyst component of the free radical initiator. In the preferred process of the present invention, only gaseous SO is used as the catalyst in the free radical initiator. This gas is present only in catalytic amounts, as previously stated. The exposure time of the contact between sand mixture and the gas can be as short as half a second or less, and the binder component cures upon contact with the catalytic agent. When SOg is used as a catalytic agent in a cold box-g jut process, it is suspended in a stream of carrier gas in a known manner. The carrier gas is usually Ng. As little as 0.5 # SOg, based on the weight of the carrier gas, is sufficient to cause polymerization. It is also conceivable to expose the binder component to SOg without the presence of any carrier gas.

Part I may also contain any constituents. For example, additives for effecting wetting and for preventing foaming may be useful. Silanes have been found to be particularly useful additives. Particularly preferred are unsaturated silanes, e.g. vinyl silanes.

The advantages of the binding composition as a casting binder are as follows. The breakability, or ability to collapse, of the binder when used for casting aluminum is excellent. It has been found that the present binder readily disintegrates, i.e. The cut-out of an aluminum casting part can be done while applying a minimum of external energy. The binder also provides good strength properties. The bench or service life of sand mixed with Part I is long. The surface area obtained, θ finish of the castings made using the present binder and method has been found to be very good. The production rate of cores and molds made using the present binder system is high, especially when alone. SQ, -Rase was used as a catalyst.

In a foundry utilizing the blend composition described herein, Part I and a component of the free radical initiator, preferably the peroxide, are mixed with sand or any other suitable casting ballast material in a known manner. The sand mixture is then molded to the desired casting configuration, cores or molds, 40 '

459 256 in known manner. The sand mixture is then exposed to the second component of the free radical initiator, preferably the catalytic agent, which is preferably sulfur dioxide gas, and polymerization of the binder material Part I occurs immediately to form the binder of the present invention.

The present invention is further illustrated by the following examples wherein, unless otherwise indicated, all parts are by weight and all percentages are by weight. Example 1

Gel tests were performed on various unsaturated monomers and polymers to determine their tendency to polymerize and the rate of polymerization. In carrying out the tests, from about 1.5 to 2 g of unsaturated monomer or polymer (ie, Part I) was mixed with 0.03 & t-butyl hydroperoxide (the peroxide component of the free radical initiator). This mixture was then exposed to SO₂~ gas (the catalytic agent in the free radical initiator), either by dispersing the gas in the liquid (bubbling) or by generating an SO 2 atmosphere above the liquid (contact). The results set forth below indicate that all unsaturated monomers and polymers polymerize. Thus, all listed compounds are potential binders. The enumerated compounds, which exhibited rapid polymerization or gelation, are of the greatest potential value as a casting agent to make the mold and core preparation fast in high-speed manufacturing using a so-called cold box.

Part I

acrylic acid

Ethyl acrylate n-butyl acrylate Isobutyl acrylate

2-ethylhexyl acrylate Isodecyl acrylate

2-ethoxyethyl acrylate Ethoxy ethoxy acrylate Butoxy ethyl acrylate Hydroxy tylacrylate Hydroxypropyl acrylate Glycidyl acrylate Dimethylaminoethyl acrylate

Polymer! Sationsförlopp

Fast, when in contact with SOp Slow, in contact with SOp

Slow, when in contact with S0₂Slow, when in contact with S0₂

Quick, when in contact with S0₂Fast, when in contact with SOg Fast, in contact with SOg Fast, in contact with S0₂Fast, when in contact with SO and Fast, in contact with S0₂Quick, when in contact with S0₂Quick, when in contact with S0₂Quick, when in contact with S0₂

459

256

Part I

Cyanoethyl acrylate Diacetonacrylamide in methanol, 50%

Acrylamide in methanol, 50% (N-methylcarbamoyloxy) ethyl acrylate

Methylcellosolve acrylate Phenoxyethyl acrylate

Benzyl acrylate Ethylene glycol acrylate phthalate

Melamine Acrylate Diethylene glycol diacrylate Hexanediol diacrylate Butanediol diacrylate Triethylene glycol diacrylate Tetraethylene glycol diacrylate

Neopentyl glycol diacrylate 1,5-butylene glycol diacrylate

Trime tylolpropane triacrylate

Pentaerythritol triacrylate Methacrylic acid

Me tyl methacrylate

2-thylhexylmethacrylate Hydroxypropylmacrylate Glycidylmethacrylate Dimethylaminoeylmethyl

Ethylene glycol dimethacrylate Trimethylol propane trimethacrylate

Acrylic pretane derived from glycerol 65% in MIAK / HiSol-10 N-methylolacrylamide in water 60%

Polymerisationsförlopp

Quick, when in contact with SOg

Quick, when in contact with SOg

Quick, when in contact with SOg

Fast, when in contact with SOg Fast, in contact with SOg

Fast, when in contact with SOg Fast, in contact with SOg

Fast, when contacting SOg Fast, when contacting SOg Fast, when contacting SOg Fast, when contacting SOg Fast, when contacting SOg Fast, when contacting SOg

Fast, when in contact with SOg Fast, in contact with SOg

Quick, when in contact with SOg

Fast, when contact with SOg Fast, when contact with SOg Fast, when contact with SOg Slow, when bubbling with SOg Slow, when bubbling with SOg Fast, when contact with SOg Fast, when contact with SOg

Fast, when in contact with SOg Fast, in contact with SOg

Quick, when in contact with SOg

Quick, when in contact with SOg

Quick, when in contact with SOg

459 256

Part I

N-physobutoxymethylJ acrylamide in methanol 50%

Epocrylic R-12 Resin ⁵ (Shell) acrylic epoxy

80% in acetone

UVITHANE 783 (Thiokol / Chem.Div.) Acrylic urethanol oligomer

AROPOL 7200 (ASHLAND) 60% acetone unsaturated polyester resin

RICON 157 (Colorado Specialty Chemical) an unsaturated hydrocarbon resin in acetone 50 #

Hydroxy PBG-2000 (Hystl Co.) an unsaturated hydrocarbon resin in acetone 50%

Polymerisationsförlopp

Quick, when in contact with SOg

Slow, when in contact with SOg

Quick, when in contact with SOg

Slow, when in contact with SOg

Slow, when in contact with SÖg

Slow, when in contact with SOg

Example 2

An unsaturated polymer was prepared by reacting the equivalent of 1 mole of pentanediol with the equivalent of 4 moles of hydroxyethyl acrylate with the equivalent of 3.0 moles of toluene diisocyanate. Dibutyltin dilaurate was used to catalyze the reaction.

Based on the solids content, 0.14% catalyst was used. Hydroquinone monoethyl ether was used as an inhibitor. The reaction was carried out in a reaction medium (solvent) which consisted of ethyl hexyl acrylate and hydroxy ethyl acrylate. In carrying out the reaction, a mixture of TDI and solvent was charged to a reaction vessel. Pentanediol is added to this mixture followed by the addition of hydroxyethyl acrylate. When the addition of hydroxyethyl acrylate is complete, catalyst is added. The reaction is carried out under air entrapment. The reaction is allowed to proceed at 40 to 45 ° C

2.1 hours, and then the temperature is raised to 80-85 ° C, and the reaction is continued for 4.3 hours, then 0.03% inhibitor is added and the reaction is continued for 1/2 hour. The product is allowed to cool. The product was tested for non-volatile material, giving the value 59.2%. This corresponds to a theoretical amount of 60% non-volatile material. The viscosity of the product was 6.0 20 g of the unsaturated polymer was then mixed

459 256 with 1.6 g of acrylic acid, 10.7 g of diethylene glycol diacrylate, 9.9 g of trimethylol propane trimethacrylate and 2.0 g of vinyl silane. Acrylic acid, diethylene glycol diacrylate and trimethylol propane triacrylate are unsaturated monomers. This solution of unsaturated polymer and unsaturated monomers is referred to as Part I. 1 g of t-butyl hydroperoxide, the peroxide component of the free radical initiator, was added to the solution of unsaturated polymer and unsaturated monomers.

Wedron 5010 sand (washed and dried fine-grained silica sand, AFSGFN 66) was placed in a suitable mixing apparatus.

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

The sand mixture was blown into a conventional core cavity or box to produce standard tensile strength briquettes in the form of test cores, which are referred to as dog bones. The dog bone test cores were cured by exposure to the catalytic component of the free radical initiator. The catalytic component is gaseous sulfur dioxide. The nuclei were exposed to the SO 2 catalyst for approximately 20 wt a 1/2 second (gas time), and the catalyst was removed by blowing with nitrogen for 15 seconds, and the core was removed from the box. 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.²⁵ Dog bone cores similar to those described above were used in shaking studies with aluminum cast details. Seven tensile strength briquettes (dog bones) were arranged in a mold. The mold contained a gate system. The shape is such that it provides hollow castings with a metal thickness of about 6.4 mm on all sides. An opening at one end of the casting member is provided to remove the core from the casting member. Melted aluminum with a temperature of about 700 ° C made of aluminum raw material was poured into the mold. After cooling for about 1 hour, the aluminum casting details were removed through^- gate system and was removed from the mold for shaking attempts.

The shaking tests are carried out in such a way that a casting member is placed in a 3.8 liter container. The container is placed on a shaking mechanism and shaken for 5 minutes. The weight of the sand core removed from the casting part in this way is compared

ICE

459 256

<td></td><td colspan="2">the original weight of the sand core, and the percentage cut-out calculated. Remaining sand in the casting part after the above-described shaking is removed by scraping and weighed as well. The sand core, bonded with the binder described above,</td>

<td> 5</td><td colspan="2">was found to have a cut-off value of 100. It should be noted that the cut-off test described above is not a standard test · We do not know of any standard test for measuring this property. The test used is well useful for that</td>

<td></td><td>one should get an idea</td><td>about the decomposition of a binding agent.</td>

<td> 10</td><td>means and for one to</td><td>be able to compare relative decomposable</td>

<td></td><td>is called binder. The</td><td>stated percentages have one</td>

<td></td><td>some degree of variation though</td><td>are reliable indicators.</td>

<td></td><td>Example</td><td></td>

<td></td><td>Sand</td><td>Wedron 5010 at 23 to 26 ° C</td>

<td>ICE</td><td>PART I</td><td></td>

<td></td><td>a) unsaturated monomer</td><td>Acrylic acid 1.6 g, diethylene glycol diacrylate 10.7 g, trimethylol propane trimethacrylate 9.9 g.</td>

<td></td><td>b) unsaturated polymer</td><td>Synthesized as described below 20 g.</td>

<td> 20</td><td>unsaturated polymer synthesis</td><td></td>

<td></td><td>i) polyisocyanate, in molecular equivalents</td><td>TDI 4</td>

<td></td><td>il) polyol, in molecular equivalents</td><td>Glycerol - 1</td>

<td> 25</td><td>iii) acrylate, in molecular equivalents</td><td>Hydroxyethyl acrylate, 5</td>

<td></td><td>lv) catalyst</td><td>Dibutyltin dilaurate, 0.14%</td>

<td></td><td>v) inhibitor</td><td>He droquinone monomethyl ether</td>

<td></td><td>will) solvent in%</td><td>Ethyl hexyl acrylate and hydroxyethyl acrylate, 40%</td>

<td> 30</td><td>viii) temp / time ° C / hr.</td><td>40 ° to 45 ° for 2.13 hours. then 80 ° to 85 ° for 4.8 hours.</td>

<td></td><td>lx) viscosity, St</td><td> 16,0</td>

<td></td><td>x)% not volatile mtrl actually theoretical</td><td> 63,9 60,0</td>

<td> 35</td><td>c) additives ig</td><td>Vinyl silane - 2.0</td>

459 256

<img file="SE459256B_D0001.tif" />

Free Radical Initiator (Part II)

a) peroxide component

b) catalytic component Gas time, sec.

Breathing time, sec. Tensile strength, MPa outside box 5 hours.

h.

Binder Level (Part I + Peroxide Component) Metal Cast Detail £

2.2 $ t-butyl hydroperoxide

S0₂-gas

0.5 with Ng

1,25

1,50

1,61

2%

Aluminum

100

Example 45

Sand

PART I

a) unsaturated monomer

Acrylic acid 1.6 g, the tylene glycol diacrylate 10.7 g, trimethylol propane triacrylate 9.9 g

Hydroxy e ty1acrylate

2.2 g, dicyclopentenyl acrylate

20.8 g (N-methylcarbamoyloxy) ethyl acrylate 17.5 g

b) unsaturated polymer unsaturated polymer synthesis

i) polyisocyanate, in molar equivalent ii) polyol, in molar equivalent iii) acrylate, in molar equivalent iv) catalyst

v) inhibitor vli) solvent in% viii) temp / time ° C / hour.

Synthesized as described below, 20 g

TDI, 5

Olin 2O-265^A), 1 ^A) polyoxypropylene glycol

Hydroxyethyl acrylate, 4

dibutyltindilaurate,

0,14$

Hydroquinone monomethyl ether

Ethyl hexyl acrylate and hydroxyethyl acrylate, 40 #

40 ° to 45 ° in 2.1 and 80 ° to 85 in 4.75

459 256

<td colspan="2">Example</td><td> --</td><td> 5</td>

<td></td><td>ix) viscosity</td><td> 4,2</td><td></td>

<td> 5</td><td>x)% non volatile mtrl actually theoretical</td><td> 59,2 60,0</td><td></td>

<td></td><td>c) additive 1 g</td><td>Vinyl silane 2.0 g</td><td></td>

<td></td><td>Free Radical Initiator (Part II)</td><td></td><td></td>

<td> 10</td><td>a) peroxide component</td><td>11.3% cumene hydroperoxide</td><td>2.4% t-butyl hydroperoxide</td>

<td></td><td>b) catalytic component</td><td>SO-gas</td><td>SO-gas</td>

<td></td><td>Guest time, sec.</td><td> 0,5</td><td> 1</td>

<td> 15</td><td>Breathing time, sec. Tensile strength, MPa</td><td>15 with Ng</td><td>15 with Ng</td>

<td></td><td>outside the box 3 hrs. 24 hrs. 48 hrs.</td><td> 1,10 1,60</td><td> 0,17</td>

<td> 20</td><td>Binder Level (Part I + Peroxide Component)</td><td> 2%</td><td> 2%</td>

<td></td><td>Metallgjutdetalj</td><td>Aluminum</td><td></td>

<td></td><td>Utskakn. %</td><td> 100</td><td></td>

<td></td><td>Example</td><td> 6</td><td> 1</td>

<td> 25</td><td>Sand</td><td>Wedron 5010</td><td>Wedron 5010</td>

<td></td><td>PART I</td><td></td><td></td>

<td> 30</td><td>a) unsaturated monomer</td><td>pentaerythritol acrylate 40 g</td><td>Acrylic acid 7.2 g, diethylene glycol diacrylate 21.4 g, trimethyl thiol propane triacrylate 13 g</td>

<td></td><td>b) unsaturated polymer synthesis</td><td></td><td></td>

<td></td><td>1) polyisocyanate, in molecular equivalents</td><td></td><td></td>

<td> 35</td><td>ii) polyol, in molecular weight t</td><td></td><td></td>

<td></td><td>lli) acrylate, i mole equivalent</td><td></td><td></td>

<td></td><td>iv) catalyst</td><td></td><td></td>

<td></td><td>v) inhibitor</td><td></td><td></td>

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<img file="SE459256B_D0002.tif" />

<td>Example</td><td> -----------5---------------</td><td> ... 7</td>

<td>will) solvent 1% vill) temp / time ° C / hour.</td><td></td><td></td>

<td>ix) viscosity</td><td></td><td></td>

<td>x)% non-volatile mtrl actually theoretical</td><td></td><td></td>

<td>c) additives ig</td><td></td><td></td>

<td>Frirad icon initiator (Part II)</td><td></td><td></td>

<td>a) peroxide component</td><td>2.4 l of t-butylhydrop is oxide</td><td>2.4 l of t-butyl hydroperoxide</td>

<td>b) catalytic component</td><td>SO-gas</td><td>SO-gas</td>

<td>Guest time, sec.</td><td> 0,5</td><td> 1</td>

<td>Inflow time, sec.</td><td> 15</td><td> 10</td>

<td>Tensile strength, MPa</td><td></td><td></td>

<td>outside the box 5 hrs. 24 hrs.</td><td> 0,55</td><td> 0,90</td>

<td>Binder Level (Part I + Peroxide Component)</td><td> 2#</td><td> 2%</td>

<td>MetallgJutdetalj Utskakn. %</td><td></td><td></td>

<td>Example</td><td> 8</td><td> 9</td>

<td>Sand</td><td>Wedron 5θ1θ</td><td>Port Crescent</td>

<td>PART (I) a) unsaturated monomer</td><td></td><td>Acrylic acid 5.2 g, diethylene glycol diacrylate 21.4 g, trimethylol propane trimethacrylate 19.6</td>

<td>b) unsaturated polymer</td><td>Synthesized as described below, 40 g</td><td>Same as Ex. 4 40 g.</td>

<td>i) polyisocyanate</td><td>TDI, 5</td><td></td>

in molar equivalent ii) polyol, in molar Olin 20-265, 1 equivalent

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Example ΰ 9

<td>iii)</td><td>acrylate, in molecular equivalent</td><td>Hydroxylethyl acrylate, 4</td>

<td>iv)</td><td>catalyst</td><td>Dibutyltin dilaura, 0.14%</td>

<td>v)</td><td>inhibitor</td><td>Hydroquinone monomethyl ether 0.07%</td>

<td>vii)</td><td>solvent</td><td>Pentoxone (93.7)</td>

<td></td><td>i%</td><td>hydroxylethyl acrylate 55%</td>

<td>viii)</td><td>Temp / Time</td><td>40 ° to 45 ° for 2 hours.</td>

<td></td><td>° C / h.</td><td>then 20 ° to 85 ° in 4</td>

<td>ix)</td><td>viscose! Tet</td><td>Thixotropic after 3 days</td>

<td>x)</td><td>% non volatile mtrl</td><td></td>

<td></td><td>actually</td><td>6j l</td>

<td></td><td>theoretical</td><td> 65</td>

<td colspan="2">c) additives ig</td><td>Vinyl Silane A-172 2.0 g Vinyl Silane</td>

acrylic acid 1.6 g

<td colspan="3">Free Radical Initiator (Part II)</td>

<td>a) peroxide component</td><td>(90%) t-butyl hydrochloride</td><td>t-butylperaceta</td>

<td></td><td>peroxide 2.2%</td><td>(6 g)</td>

<td>b) catalytic com.</td><td>S0_O-gas</td><td>Heat 450 ° i</td>

<td>component</td><td>t</td><td>90 sec.</td>

<td>Guest time, sec.</td><td> 0,5</td><td></td>

<td>Inflow time, sec.</td><td>15 with N₂</td><td></td>

<td>Tensile strength, MPa</td><td></td><td></td>

<td>outside the box</td><td> 0,37</td><td> 0,52</td>

<td>3 hrs.</td><td> 0,64</td><td></td>

<td>24 hrs.</td><td></td><td></td>

<td>cold strength</td><td> 1,07</td><td> 1,10</td>

<td>Blndemedelsnivå</td><td></td><td></td>

<td>(Part I + peroxide-</td><td> 2%</td><td> 2%</td>

component)

Metallgjutdetalj

Utskakn. %

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<td>Example</td><td> 10</td><td> 11</td>

<td>Sand</td><td>Wedron 5θ1θ</td><td>Wedron 5010</td>

<td></td><td>PART I a) unsaturated monomer</td><td>Acrylic acid 1.6 g,</td><td>Same as Ex. 10</td>

<td> 5</td><td></td><td>trimethylol propane triacrylate 9.9 g</td><td></td>

<td></td><td>b) unsaturated polymer</td><td>Synthesized as described below, 20 g</td><td></td>

<td></td><td>unsaturated polymer synthesis</td><td></td><td></td>

<td> 10</td><td>1) polyisocyanate molecular equivalent</td><td>TDI, 3.5</td><td></td>

<td></td><td>il) polyol, in molecular valent</td><td>Glycerol-diethylene glycol mixture (1: 1), 1</td><td></td>

<td> 15</td><td>ill) acrylate, in molar equivalent</td><td>Hydroxyethyl acrylate 4.5</td><td></td>

<td></td><td>iv) catalyst</td><td>Dibutyltin 0.14%</td><td></td>

<td></td><td>v) inhibitor</td><td>Hydroquinone monomeric tyl ether 0.07%</td><td></td>

<td> 20</td><td>(vii) solvent in%</td><td>Ethyl hexyl acrylate + hydroxyethyl acrylate (4: 6) 40%</td><td></td>

<td> 25</td><td>viii) temp / time ° C / hr.</td><td>40 to 45 ° for 2 hours. then 80 to 85 ° for 4.8 hours.</td><td></td>

<td></td><td>ix) viscosity</td><td>10 pieces</td><td></td>

<td> 30</td><td>x)% non-volatile mtrl actually theoretical</td><td> 59,9 60,0</td><td></td>

<td></td><td>c) additives ig</td><td>Vinyl silane A-172, 2 HiSol 10 10.7</td><td></td>

<td></td><td>Free Radical Initiator (Part II)</td><td></td><td></td>

<td> 35</td><td>a) peroxide component</td><td>70% t-butyl hydroperoxide 2.2%</td><td></td>

<td></td><td>b) catalytic component</td><td>SO-gas</td><td>1/2% S0₂gas in N₂carrier gas</td>

<td></td><td>Guest time, sec.</td><td> 0,5</td><td> 1/2</td>

<td> 40</td><td>Start time, sec. Tensile strength, MPa</td><td>With N 2 gas</td><td>No</td>

<td></td><td>outside the box</td><td> 1,57</td><td> 0,48</td>

<td></td><td>3 hrs.</td><td> 1,57</td><td> 0,84</td>

<td></td><td>24 hrs.</td><td> 1,77</td><td> 1,54</td>

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<td>Example</td><td> 10</td><td> -----_n-----</td>

<td>Binder Level (Part I + Peroxide Component)</td><td> 2%</td><td> 1,5</td>

<td>Metallgjutdetalj</td><td>Aluminum</td><td></td>

<td>Utskakn. %</td><td> 100</td><td></td>

<td>Example</td><td> 12</td><td></td>

Sand

PART I

a) unsaturated monomer

b) unsaturated polymer unsaturated polymer synthesis

1) Polyisocyanate Molecular Equilibrium Polyol in Molecular Valent Acrylate, Molecular Valve iv) Catalyst

v) inhibitor vii) solvent in% viii) temp / time ° C / hour.

ix) viscous, St

x)% non-volatile mtrl actually theoretical

c) additives ig

Free Radical Initiator (Part II)

a) peroxide component

b) catalytic component Gas time, sec.

Breathing time, sec. Draw hole IF, MPa outside box hour.

h.

Wedron 5θ1θ

Acrylic acid 1.6 g, diethylene glycol 539, trimethylol propane triacrylate 9.9

Synthesized as described below, g

Glycerin 1

hydroxyethyl

Dlbutyltin dilaurate 0.14

Hydrocarbon monomethyl ether 0.05

Methyl isoamyl ketone, HiSol 10 (65:35)

$ 35 to 45 ° for 1.75 hours. then to 85 ° for 4.5 hours.

64,1

Vylnylsilane 2.0, HiSol 10 5.5

2.2% t-butyl hydroperoxide - 70

1% S0₂gas in N₂~ carrier gas

No

1,50

1,08

1,61

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<td colspan="2">Example 12 ——————————</td>

<td>binder Level (Part I + peroxide component) Metallgjutdetalj Utskakn. %</td><td>1.5 Aluminum 100</td>

<td>Example</td><td> 15</td>

<td>Sand</td><td>Wedron 5θ10</td>

<td>PART I a) unsaturated monomer</td><td>Acrylic acid 1.6 g, diethylene glycol 539, trimethylol propane triacrylate 9.9</td>

<td>b) unsaturated polymer</td><td>Synthesized as described below, 20 g</td>

<td>unsaturated polymer synthesis</td><td></td>

<td>i) polyisocyanate molecular equivalent</td><td> 4</td>

<td>ii) polyol, in molar equivalent</td><td>Glycerol - 1</td>

<td>iii) acrylate, in molar equivalent</td><td>hydroxyethyl</td>

<td>iv) catalyst</td><td>Dibutyltin dilaurate 0.14</td>

<td>v) inhibitor</td><td>Hydroquinone monomethyl ether 0.05</td>

<td>(vii) solvent in%</td><td>Methyl isoamyl ketone, HiSol 10 (65:55) 55%</td>

<td>viii) temp / time ° C / hr.</td><td>40 to 45 ° for 1.75 hours. then 80 to 85 ° in A, 5 hours.</td>

<td>ix) viscosity, St</td><td> 10</td>

<td>x)% non volatile mtrl</td><td></td>

<td>actually theoretical</td><td> 64,1 65</td>

<td>c) additives ig</td><td>Vinyl silane 2.0 Hi Sol 10 5.5</td>

<td>Free radi kalini tia tor (Part II)</td><td></td>

<td>a) peroxide component</td><td>2.2% t-butyl hydroperoxide - 70</td>

<td>b) catalytic component</td><td>SO-gas</td>

<td>Guest time, sec.</td><td> 0,5</td>

<td>Breathing time, sec.</td><td>15 with air</td>

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<td colspan="2">Example</td><td> 13</td>

<td>Tensile strength, MPa</td><td></td><td></td>

<td>outside the box</td><td> 1,22</td><td></td>

<td>3 hrs ·</td><td> 0,66</td><td></td>

<td>24 hrs.</td><td> 1,03</td><td></td>

<td>binder Level</td><td></td><td></td>

<td>(Part I + peroxide component)</td><td> 1,5</td><td></td>

<td>With numerous jute details</td><td colspan="2">Aluminum</td>

<td>Utskakn. %</td><td> 100</td><td></td>

Particularly preferred embodiments of the method of the invention can be summarized as follows:

In the process of the invention, the binder material may comprise a mixture wherein the acrylic monomer is mixed with at least one other ethylenically unsaturated monomer. Furthermore, the binder material may comprise at least one ethylenically unsaturated polymer in addition to the acrylic monomer. Conversely, the acrylic polymer in the binder composition may be blended with at least one ethylenically unsaturated monomer or at least one other ethylenically unsaturated polymer. For example, the acrylic polymer can be be an oligomer or an adduct.

The catalytic agent is conveniently suspended in a carrier gas and exposed to the binder material for at least 0.5 seconds.

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