DE2923131A1 - BINDING AGENT FOR MOLDING FOR LIGHT METALS - Google Patents

Description

In the field of manufacturing foundry molds and cores, the cold-box process and the no-bake process are used known.

In connection with the cold-box process, there are already urethane-forming binders for binding appropriate binders Molding materials (see U.S. Patent 3,409,579).

With regard to the no-bake process, binders are also used for molding materials for the production of foundry molds and cores (see U.S. Patent 3,676,392).

In foundry technology, there has long been a need for suitable binder systems for cold-box and the no-bake process, these binder systems being the Manufacture of foundry molds and cores intended to enable the casting of light metals such as aluminum and magnesium, are suitable. Corresponding known binders for these processes in the field of light metal casting do not give the desired properties of the molds and cores and also do not lead to good shaking behavior. If a sufficient amount of the binder is used to ensure the necessary strength and abrasion resistance of the To achieve shapes and cores, the shapes and cores do not disintegrate at the casting temperature of the light metals. the The result is poor shaking behavior of the forms and Cores.

The invention is therefore based on the object of new binder systems to make available, on the one hand, the production of non-fragile foundry molds and cores allow, but on the other hand, a slight disintegration of these

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Molds and cores at temperatures below the casting temperature of ferrous metals, for example at the casting temperature of aluminum or magnesium. It should be possible to use these binders according to the cold-box or no-bake process.
ο

This object is achieved by the invention.

The invention relates to the characterized in the claims

th item.

It has been found that binders can be used for the production of foundry molds and cores which are based on based on the reaction between a polyisocyanate and an amine polyol, whereby urethanes are formed. The binder can be cured quickly by using a gaseous tertiary amine as a catalyst. It turned out that a polyol made by reacting an amine with an alkylene oxide with a

cold-box- or no-bake- - ₀ polyisocyanate can be combined and thereby a / Binaemit-

system, which, after mixing with sand or another suitable molding material and subsequent hardening, allows foundry molds and cores to be produced that have excellent processing properties, such as strength, abrasion resistance and lack of brittleness. These good properties are achieved at the same time as excellent shaking behavior when casting non-ferrous metals. It is especially to be emphasized that this combination schüttelverhalten of good processing properties with a good initial Q ₃ is particularly valuable and is achieved at low temperatures during the application of the binders according to the invention in the field of metal casting. A catalyst can also be used to harden the binder. Suitable catalysts for the cold-box-Verg ₅ drive are gaseous tertiary amines or those amines that can be supplied in the form of a vapor. Preferred

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. Catalysts are trimethylamine, dimethylethylamine and triethylamine. In the case of the no-bake process, a catalyst is not a necessary part of the binder system. However, suitable catalysts can also be added in this case, preferably when certain amine polyols are used and rapid curing is desired. The curing of the binder according to the invention is based in part on the autocatalytic effect of the amine polyols. Therefore, according to the invention, the no-bake method can be used

IQ of a two-component system instead of the typical urethane system, that requires at least three components. Although the autocatalytic effect of the invention Amine polyols used means a significant advance, it is also possible to use the inventive

.J ₅ to combine binders with additional catalysts on a case-by-case basis.

According to the invention, two-component systems are generally used used to form the molding material. Part A is the amine polyol. Part B is the polyisocyanate. Both Parts are in liquid form, generally as solutions in organic solvents. To apply this The urethane-forming binder system becomes the part containing the amine polyol with the part containing the polyisocyanate combined. When used in foundry technology, i.e.

in the manufacture of foundry molds and cores, is preferred one of the two parts is first mixed with the molding material, such as sand. Then the other part is added. After the binder system has been uniformly distributed over the molding material, the molding compound obtained becomes the desired one Shape deformed. The shape obtained in this way can be left to stand and cures at room temperature. As already mentioned, the binder systems based on the invention are generally to some extent autocatalytic. That is, after the amine polyol is mixed with the isocyanate, their reaction occurs as follows

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happens quickly that a catalyst is not required. The degree of reactivity between the amine polyol and the polyisocyanate depends on the reactivity of the polyol. The molding compounds formed into foundry molds or cores can also be cured by treatment with a gaseous catalyst.

Despite the autocatalytic properties of the invention binder systems obtained can be used in the no-bake process

IQ ren liquid amine catalysts or metallic catalysts are used, which are known in urethane technology. In some cases it is the use of a catalyst even expedient and preferred. By choosing a suitable catalyst, the conditions of the for

• J5 production of a foundry core chosen process, e.g. the processing time and the disconnection time, in the desired Way to be set. For economic reasons, it may be necessary to use catalysts when using certain polyols therefore add to sufficient production speeds to achieve.

The binders according to the invention can be used in the cold-box process can be combined with gaseous amines as catalysts. The hardening stage can be carried out in such a way that one tertiary amine entrains in an inert gas stream and the gas mixture obtained under sufficient pressure through the shape to be hardened passes until the binder system is hardened.

The binders according to the invention only require one extremely short curing time until a sufficient tensile strength of the mold to be cured is reached. This point of view is of great economic importance. The optimal curing times can easily be determined experimentally. There to harden only catalytic amounts of the tertiary amine required a very dilute gas

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.j current with the catalyst. However, there are also excesses Concentrations of the tertiary amine above the required concentration are not harmful to the cured product. Air, carbon dioxide or nitrogen, for example, can be used as inert gas, in which 0.01 to 20 percent by volume of the tertiary amine. Normal gaseous tertiary amines can be used as such or after dilution by the Form. Suitable tertiary amines are gaseous tertiary amines such as trimethylamine. However, normal

IQ usually liquid tertiary amines, such as triethylamine, in volatile form ger form or in the form of a mixture with a gaseous medium in the same way for introduction into the to be hardened Suitable shape. Although ammonia, primary and secondary amines also have some effectiveness, at room temperature Catalyzing the curing reaction are these compounds not as beneficial as tertiary amines. The tertiary amines also include substituted amines, such as dimethylethanolamine, to understand; they can also be used as catalysts. Occurring as substituents in such amines functional groups that do not impair the effectiveness of the tertiary amines are e.g. hydroxyl, Alkoxy, amino, alkylamino, ketoxy and thio groups.

The amine polyols used according to the invention in binder systems are normally made as the reaction product of an amine with an alkylene oxide. Under the expression “Amine polyol” in this context is such a reaction product to understand, but this designation is not limited to the reaction products on a such synthetic route have been obtained. In general, the term "amine polyol" is to be understood as meaning any polyol which contains at least one tertiary amino group "

The alkylene oxides used to prepare the aforementioned amine polyols are preferably ethylene oxide and propylene oxide. However, other alkylene oxides can also be used for this purpose

81 / 08SS

will. The molar ratio of alkylene oxide to amine can be very high to be different. It is assumed that the degree of alkoxylation has no decisive influence on the properties of the product obtained Amine polyol has to act as a binder. 5

Examples of amines that react with alkylene oxides according to the invention Amine polyols that can be used are ammonia, mono- and polyamines with primary and secondary amino groups. Specific Examples are aliphatic amines, such as primary alkylamines, Ethylenediamine, diethylenetriamine and triethylenetetramine, cycloaliphatic amines and aromatic amines such as o-, m- and p-phenylenediamine and aniline-formaldehyde resins. Mixtures of the aforementioned amine polyols can also be used. Mixtures of amine polyols are also possible other polyols, such as amine-free polyols, are suitable. It is assumed that amines, a polyol with by alkoxylation result in at least two reactive hydroxyl groups, can be used according to the invention. The type of used Polyol affects foundry core production conditions. In the cold-box process, in which a Molding material coated with the binder system, e.g. sand, is hardened by gassing with an amine as a catalyst, the processing time is an essential property of the binder. This processing time is the same as with the no-bake

the

Process the time during which sand mixed with the binder can be processed. After the binder has been mixed with the molding material, the binder begins to react. After a certain time the reaction is so far that the mixture of sand and binding agent can no longer be processed. The time after the sand has been mixed with the binder system until the point in time at which this molding compound is no longer processed is referred to as "processing time" in the cold-box method. It was found that the insert aromatic amine polyols brings an unexpected extension of the processing time with it. This surprising result is of great value »

^L 90988 1/0655 ~

r ^ 292313t π

- Tb -

As mentioned above, it has been found to be useful to combine an amine polyol with another polyol with a polyisocyanate can react to mix. One advantage results in particular with regard to the strength of the foundry mold after treatment with the catalyst and after demolding. Are particularly preferred in this context Phenolic resins containing hydroxyl groups, which are used in foundry technology are known as PEP resins (see U.S. Patent 3,485,797). Such resins have, for example, the -IO given structure on j where the ratio of m to the number of hydrogen atoms represented by R is at least 1.

The binders according to the invention are combined with the second component of the binder system. These are aliphatic, cycloaliphatic or aromatic polyisocyanates with preferably 2 to 5 isocyanate groups ^ It is also possible to use mixtures of different polyisocyanates or isocyanate prepolymers, prepared by reacting an excess of polyisocyanate with a polyhydric alcohol, such as tolylene diisocyanate and ethylene glycol. Specific examples of suitable polyisocyanates are aliphatic polyisocyanates such as hexamethylene diisocyanate, alicyclic polyisocyanates such as 4,4'-dicyclohexylmethane diisocyanates and aromatic polyisocyanates such as 2,4- and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate and the corresponding dimethyl derivatives. Further examples of suitable polyisocyanates are 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, xylene diisocyanate and the corresponding methyl derivatives, polymethylene polyphenyl isocyanates and the corresponding methyl derivatives and also chlorophenylene-2 _f 4-diisocyanate. Although all polyisocyanates react with the amine polyol to form a crosslinked polymer structure, aromatic polyisocyanates, in particular diphenylmethane diisocyanate, triphenylmethane triisocyanate and mixtures thereof, are preferred.

The polyisocyanate is generally used in an approximately stoichiometric amount, i.e. in an amount that is necessary for curing

^L 909881/0655

of the amine polyol is sufficient. However, from this amount can be within certain limits can also be deviated from, which is even advantageous in some cases. Generally this will Polyisocyanate in an amount of 10 to 500 percent by weight, preferably 20 to 300 percent by weight, based on the amine polyol, used. The polyisocyanate is used in liquid form. Liquid polyisocyanates can be used in undiluted form can be applied. Solid or viscous polyisocyanates can be used in this form or in the form of solutions in organic solvents may be added, the solvent being present in an amount up to 80 percent by weight of the solution.

Although the solvent used in combination with either the amine polyol or the polyisocyanate or both in a significant amount of reaction between the isocyanate and the amine polyol does not participate, it can interfere with the reaction. The difference between the polyisocyanate and the amine polyol in terms of polarity restricts the choice of solvents in which both compounds are compatible. This compatibility is necessary for a complete reaction and hardening of the invention To achieve binder. Polar solvents of the protic or aprotic type are good solvents for Amine polyols. Therefore, solvents or combinations of solvents are preferably used in which the

or the solvents for the polyol with the solution (s) for the polyisocyanate

medium (s) / are compatible with each other. Besides the point of view the compatibility are the solvents for the

3Q polyol or the polyisocyanate selected in such a way that a low viscosity, a low odor and a high boiling point are achieved. Examples of such solvents are benzene, toluene, xylene, ethylbenzene and mixtures of these solvents. Preferred aromatic solvents are those and their mixtures, which have a high aromatic content and a boiling range of 138-385 ⁰ C.

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The polar solvents are not intended to be extremely polar so that they do so when combined with the aromatic solvent become incompatible. Suitable polar solvents are generally those known as solubilizers, such as furfural, cellosolve, glycol diacetate, butyl cellosolve acetate and isophorone. Some reactive polyols can also be used as solvents. It was even ge found that under certain conditions water is suitable as a solvent for the amine polyol.

The components of the binder system become a molding compound with one another and then with sand or a similar molding material mixed. The molding material can also be mixed with individual components one after the other. Distribution methods of the binder on the particles of the molding material are known. The molding compound can optionally also contain others Ingredients such as iron oxide, milled flax fibers, wood, grain materials, pitch and refractory materials in powder form, contain. The molding material, e.g. sand, is generally the main component of the molding compound, while on the other hand the binder is present in a smaller amount. Although the sand is preferably used in dry form, it can a certain amount of moisture will be allowed. This is particularly true when the solvent used is immiscible with water, or an excess of polyisocyanate is required for curing. In the latter In this case, the excess polyisocyanate reacts with the water. The water is a good solvent for the amine polyol represent.

The excellent shaking behavior and the disintegration properties of the foundry cores produced according to the invention is of particular importance. The binders according to the invention disintegrate easily and thus enable the foundry core to be separated from the casting. So far the shaking was with Castings which are made under relatively low temperatures, e.g. at 982 ° C or below, a large one

^L 909881 / 065S.

Problem. Generally, non-ferrous metals such as aluminum and magnesium are cast at these temperatures. if if the binder does not break down, this leads to great difficulties in separating the sand from the casting.

Foundry cores with a low degree of shaking or disintegration, i.e., with a low degree of binder degradation, require a longer time and high energy, to separate the sand from the casting. The use of the binders according to the invention leads in many cases to one practically 100 percent shaking without external energy supply. This improvement in the distribution is due to the invention Use of amine polyols attributed. The person skilled in the art is aware that the shaking behavior of a Foundry core depends on the amount of binder used to bind the sand particles in a coherent foundry mold is used.

The percentage of binder used, based on the weight of the sand, depends on the properties desired of the foundry core. As the amount of binder increases, the tensile strength of the foundry cores also generally increases. Accordingly, the amount of the binder is varied depending on the desired properties. A preferred range of amounts for the binders according to the invention is 0.7 to 2.5%, based on the molding material, e.g. sand. However only 0.5% or 10% binders can also be used, with advantageous properties for certain applications be achieved. However, it must also be taken into account that the greater the proportion of binder, the greater the degree of shaking can decrease.

The examples illustrate the invention. Parts and percentages relate to weight, unless otherwise stated.
35

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Example!

By reacting 1.0 mole of ethylenediamine with 4.2 moles of propylene oxide a propoxylated amine polyol is produced. Prepare a 40 percent solution of the amine polyol in one commercial aromatic solvent (HISOL 10). This solution is referred to below as "Part I".

Separate from this is a 75 percent solution of a polyisocyanate based on Mondur MR (commercially available from Mobay) in an aromatic solvent "HISOL 10". The isocyanate solution obtained is called "Part II" designated.

Washed and dried, finely ground silica sand (Wedron 5010, AFSGFN 66) is placed in a mixer. Part I is mixed with the sand until the latter is evenly coated. Part II becomes the coated sand given and mixed in until a homogeneous distribution is achieved. The polyisocyanate is in slight excess over the stoichiometric amount used to achieve complete reaction of the hydroxyl group of the polyol. The amount of binding agent (Part I and Part II) is 1 1/2%, based on the weight of the sand.

The mixture of sand, amine polyol and polyisocyanate is placed in a core box. Standard test specimens, so-called "dog bones ¹ ^" are produced to determine the tensile strength. This results in a processing time of 5 1/2 minutes and a stripping time of 8 minutes. The tensile strengths after 2, 4 and 24 hours are 21.1, 26 , 1 and 27, Z kg / cm ² .

The test specimens are used as cores in examinations of the discharge used with aluminum castings. 7 of the aforementioned Test specimens are arranged in a mold which is provided with a pouring system. The shape is designed so that hollow castings with a metal layer thickness of about

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6 mm on all sides. An opening is provided at one end of the casting in order to remove the core from the casting. Aluminum melted from aluminum blocks at a temperature of about 704 ^° C. is poured into the mold. After about one hour of cooling, the aluminum castings are broken off from the pouring system and removed from the mold in order to carry out the shake-out test.

This is done by placing a casting in a container is given, which holds about 3.79 liters. The container is placed on a shaker and agitated for 2 minutes held. The weight of the sand core, which is separated from the casting in this way, becomes the original weight of the sand core, which gives the percentage of the shaking amount is calculated. The sand that remains in the casting after shaking it is scraped out and also weighed.

It turns out that the inventive with the aforementioned Sand core produced by binding agent without using the shaking device and without supplying external mechanical energy disintegrates and flows out of the aluminum casting. The amount to be extracted is 100%.

Examples 2 to 6

Test specimens are produced according to Example 1, the components specified below being used and the following values result. Shaking out is also carried out according to Example 1.

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2 B e 3 i s ρ i e 1 5 6th Wedron
5Ο1Ο. Wedron
5Ο1Ο 4th Wedron
5Ο1Ο Wedron
5Ο1Ο sand Diethylene-
triamine Wedron
5Ο1Ο Ethylene
diamine Amine Propylene
ox id Triethy
len-
tetramine Propylene
oxide Alkylene oxide
(AO) 5.1.-1 Propylene
oxide 12: 1 Molar ratio
AO: Amin A. 6.2: 1 B. Amino polyol C. C. C. C. Polyisocyanate 40
D. lo
Isopho
ron C. 60
D. 60
D. solvent
in the amine polyol,
% without without 6O
Isopho
ron 25th
D. 25th
D. solvent
in polyisocya
nat,% without without 25th
D. without without catalyst 5 2 without 6th 5 Processing
time, min 12th 4.5 0.5 9 8th Switch-off time,
min 1.5 1.5 1, O 1.5 1.5 Binder,% 4O
6O 50
50 1.5 50
50 50
5O Part One, %
Part II,% 60
4O Tensile strenght,
kg / cm ² 7.03 10.7 25.3 23.8 2 hours 8.3O 14.8 5.98 25.7 24.6 4 hours 11.4 17.4 7.94 16.2 26.9 24 stands _

Shaking volume,

1OO

100

1OO

100

1OO

A = triethanolamine (UPJOHN Corp.).

B = propoxylated ethylenediamine, molar ratio

Wyandotte. C = Mondur MR

D = HISOL IO.

1, QUADROL BASF

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It turns out that the foundry cores without the use of the shaker and disintegrate without supplying external mechanical energy and flow out of the casting.

Example 7

By propoxylating 1 mole of m-phenylenediamine with 4.2 moles Propylene oxide is an aromatic amine polyol made. Prepare a 40 percent solution of the aromatic Amine polyol by dissolving in the aliphatic solvent Butyl cellosolve. The resulting solution gives part I.

A 75 percent solution of a polyisocyanate based on Mondur MR is made using the commercially available aromatic Solvent HISOL 10 produced. The isocyanate solution gives part II.

An approximately stoichiometric amount of the polyisocyanate is used in order to achieve complete conversion of the hydroxyl groups of the polyol.
20th

Sand, which corresponds to the sand used in Example 1, is placed in a mixer. Part I is with mixed with the sand until an even coating of the sand is achieved. In Part I, triethylenediamine was used as a urethane catalyst incorporated / which is commercially available under the name DABCO. This catalyst is as Urethane catalyst known. 0.8% catalyst, based on Part I, is used. Part II becomes that coated sand and mixed until homogeneous distribution. There will be 1 1/2% binder (Part I and Part II) based on the weight of the sand.

According to Example 1, test specimens are produced in a core box. The processing time is 70 minutes, the disconnection time 110 minutes. The tensile strength after 24 hours

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T carries 16.2 kg / cm ² .

According to Example 1, the test specimens obtained are as Cores used in the casting of aluminum. The shake-out test is also carried out according to the example

It turns out that the with the binder according to the invention produced cores disintegrate without using the shaking device and without supplying external mechanical energy and flow out of the aluminum casting. The amount to be extracted is 100%.

Examples 8 to

Test specimens are produced according to Example 7, using the components given below and those given below given values can be obtained. The shaking test with the aluminum castings is carried out according to the example

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example

10

11

sand
5
Amine polyol Wedron
5Ο1Ο
E. Polyisocyanate C. Solvent in
Amine polyol,% 40
D. Solvent in
10 polyisocyanate,% 44
G Catalyst,% 1.4
H Processing time,
min 25th 15 Stripping time, min 31 Binder,% 1.5 Part One, %
Part II.% 5O
50

Tensile strength, kg / cm ²

2 hours 15.8

4 hours

24 hours 25.9

Shaking volume,

% Wedron
5010

35
water

without
without

10
16
1.7

Wedron
5010

F.
C.

35
D.

35
G

without

11.5
16
1.5

5O
5O

Wedron 5010

F C

35 D

35 G

1 1/2 H.

1O.5 1.5

50 50

7.59 14.3 15.7
(3 hours) 9.0
(3 hours) 15.0 14.8 - 22.8 22.5 1OO 100

E = propoxylated aromatic amine, Pluracol 767, BASF Wyandotte F = ethoxylated aromatic amine, Pluracol 795, BASF Wyandotte G = mixture of HISOL 10 and kerosene

H = mixture of 50% phenylpropylpyridine and 50% of a lithium salt a carboxylic acid.

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Without using a shaking device and without supplying external mechanical energy, the cores disintegrate and flow out of the casting.

Example 12 By propoxylating one mole of o-phenylenediamine to 4.2 moles Propylene oxide is an aromatic amine polyol made. A 40 percent solution of the aromatic amine is prepared. polyols by dissolving in isophorone. You get part I.

The polyisocyanate Mondur MR is used as part II. An almost stoichiometric amount of the polyisocyanate is used, to ensure a complete reaction of the hydroxyl groups of the

To achieve polyols.
15th

Sand, which corresponds to the sand used in Example 1, is placed in a mixer. Part I is according to the example 1 mixed in. In Part I, a 33 percent solution of triethylenediamine (commercially available under "DABCO") incorporated as a urethane catalyst in the propylene glycol. This catalyst is known as a urethane catalyst. There are 1.0% catalyst, based on the weight of Part I, used. Part II is then added to the coated sand and until it is evenly distributed mixed. The amount of binder (55% Part I and 45% Part II) is 1 1/2% based on the weight of the sand.

Test specimens are produced according to Example 1. The processing time is 9 minutes, the disconnection time is 20 minutes. The tensile strengths after 2 and 24 hours are 20.4 and 22.0 kg / cm ² .

The test specimens obtained are used according to Example 1 as cores for aluminum castings. Then according to Example 1 carried out the shake-out test.

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^ It turns out that with the binder according to the invention produced cores disintegrate without the use of a shaking device and without the supply of external mechanical energy and flow out of the casting. The amount to be extracted is

₅ 100%.

Examples 13 to

According to Example 12 Test bodies are prepared, said components indicated below and used the demand ₁₀ following the single values are obtained. The cores are also shaken out of the castings according to the example

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example

20th

25th

sand
Amin

Alkylene oxide

AO molar ratio: amine polyol polyisocyanate

Amine polyol solvent,%

Solvent in the polyisocyanate

Catalyst

Processing time, min

Stripping time, min binder,%

Part I,% Part II,%

Tensile strength, kg / cm ²

2 hours

4 hours 24 hours shaking volume,%

13th 14th 15th Wedron
5Ο1Ο Wedron
5Ο1Ο Wedron
5010 m-phenylene
diamine σ aniline PropyXene oxide Propylene oxide Propylene oxide 4.2: 1 4.2: 1 2.2: 1

60 isophorone

45 78 1.5

10.2 21.6 22.5 89

60 isophorone

without without

7O 101 1.5

73 27

1.62

9.84 100

60 K

without

1% dabco

70 140 1.5

61 39

12.7

74

30th

J = aniline-formaldehyde resin CURITHANE 1O3, Upjohn. K = mixture of 40% butyl cellosolve acetate and 20% HISOL 10.

It turns out that the with the binder according to the invention produced cores without the use of a shaking device 35 and without the supply of external mechanical energy disintegrate and flow out of the casting.

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- ζο -

Example 16 By propoxylating 1.0 mole of m-phenylenediamine to 6.0 moles Propylene oxide is an amine polyol made. A 40 percent solution of the amine polyol is prepared with 60% of a solvent mixture, consisting of 40% isophorone, 16.5% of an aromatic solvent and 3.5% kerosene. Included Part I is obtained.

A 75 percent solution of a polyisocyanate based on Mondur MR in HISOL 10, an aromatic solvent, is prepared. The isocyanate solution represents part II. An approximately stoichiometric amount of the polyisocyanate is used in order to achieve complete reaction of the hydroxyl groups and the polyol.
15th

Sand of the type used in Example 1 is poured into a mixer given. Part I is mixed with the sand until it is evenly distributed. Then the Part II added and also mixed in uniformly. The amount of binder (for part I and part II in equal amounts) is 1 1/2% based on the weight of the sand.

The mixture of sand, amine polyol and polyisocyanate is blown into a customary core box for the production of standard test specimens (to determine the tensile strength), so-called "dog bones". The test specimens are cured by gassing with a tertiary amine catalyst. The catalyst used is methylethylamine, which is mixed with carbon dioxide as an inert carrier gas. The test specimens are exposed to the amine for about 20 seconds (gassing time) and then remain in the core box for 10 minutes (residence time) until they are removed therefrom. The tensile strengths are 1.76 kg / cm ² after removal (immediately), 5.06 kg / cm ² after 1 hour and 9.49 kg / cm ² after 24 hours. The test specimens obtained are used as in Example 1 as cores when casting aluminum.

The shaking test according to Example 1 is then carried out .

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1 It can be seen that those produced with the binder according to the invention Cores disintegrate and expire without the use of a shaker and without the use of external mechanical energy flow out of the casting. The amount to be extracted is 100%. 5

Examples 17 to

Cores are manufactured and tested according to Example 16 using the components specified below. It will obtained the values given below. 10

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- 3Ο -

sand
Amine

Alkylene oxide

Molar ratio
AO: amine

tO polyisocyanate

Solvent in the amine polyol,%

example

17th

Wedron 5Ο1Ο

aniline

Propylene oxide

2: 1 C

60 L

Solvent in without polyisocyanate,%

catalyst

Trim

ethyl

amine

Fumigation time,

sec OK

Dwell time,

min 5

Tensile strenght,
kg / cm ²

immediately 2.11

1 hour
24 hours 6.33 binder,%

(all components) 1.5 part I,% 75 part II,% 25 shaking volume,

% 1OO

18th

Wedron
5010

o-phenylene

Propylene oxide

4.2: 1
C.

60

Isophorone

25th
M.

Dirnethylethylarain
in CO ₂

10

19th

Wedron
5010

m-phenylene

Propylene oxide

4.2: 1
C.

60
Isophorone

25th
D.

Dimethylethylarain
in C0 "

IO

20th

Wedron Wedron

5010 5O1O

m-phenylenediamine

Propylene propylene

oxide oxide

8: 1

6O L

25 M.

4: 1 C

6O

Isophorone

without

Dimethyl- trimethylethylamine amine in CO _n

20th

10

3, 52 0, 35 7, 03 4, 57 5, 98 7, 94 if 5 i, 5 50 5O 50 50

7.38 7.33

_f 5

100

loo

50 SO

100

1.5 75 25

1OO

= 40% isophorone, 16.5% aromatic solvents and

3.5% kerosene = 19% aromatic solvent (Texaco Solvent 7545) and

6% kerosene.

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It turns out that with the binder according to the invention produced cores without the use of a shaking device and without the supply of external mechanical energy disintegrate and flow out of the casting.

Example 22

By propoxylation of 1.0 mole of m-phenylenediamine with 3, O mol propylene oxide amine polyol is prepared. A phenolic polyol (PEP resin) is added to this to produce a polyol mixture. The ratio of o-amine polyol to the amine-free polyol is 2: 1. A 60 percent solution of the polyol mixture in isophorone is prepared. You get part I.

It is a 75 percent solution of a polyisocyanate based on Mondur MR using 25% solvent 19% of which is Texaco 7545 aromatic solvent and 6% kerosene. The isocyanate solution represents part II. A nearly stoichiometric amount of the polyisocyanate is used to achieve a complete To achieve reaction of the hydroxyl groups of the polyols.

Parts I and II are mixed with sand as in Example 16. The proportion of binder (44% Part I and 56% Part II) is 1 1/2% based on the weight of the sand.

According to Example 16, the mixture of sand, polyol and polyisocyanate is blown into a core box. The hardening takes place by adding dimethylethylamine mixed with carbon dioxide. The active bodies are treated with the catalyst for about 5 seconds and then left to stand in the core box for a residence time of 1 minute before they are removed therefrom. The tensile strengths are 4.08 kg / cm ² immediately after removal, 14.1 kg / cm ² after 1 hour and 14.8 kg / cm ² at the time of casting.

909881/0655

According to Example 1, the test specimens are used as cores when casting aluminum. The following is the shake-out test carried out according to Example 1.

It turns out that the with the binder according to the invention produced cores without the use of a shaking device and without the supply of external mechanical energy disintegrate and flow out of the casting. The amount to be extracted is 100%.

B e sand games 23 and 23 24 24 Arain By S Wedron 5010 ρ i e 1 Wedron 5010 Alkylene oxide J Amine polyol Propylene oxide Amine-free polyol N Amine polyol ratio:
amine-free polyol phenolic polyol phenolisehe Polyisocyanate 2: 1 2: 1 Solvent in
Polyol mixture,% C. Solvent in
Polyisocyanate,% 40
Butyl cellosolve acetate 40
Butylcellosi 25 M.
6 kerosene 25th
Kerosene

catalyst

Gassing time, see residence time, min tensile strength, kg / cni ²

Trimethylamine 5

Trimethylamine 5 1

Binder,% (all components) Part I,%

Part II,%

Shaking rate,%

3.16

8.93 (1 hour) 7.73 (4 hours) 11.4 (time of pouring)

1.5 44 56

100

3.66

8.79 (1 hour)

8.93 (time of pouring)

1.5 50 50

48

N = ethoxylated aromatic amine polyol, BASF

909881/0655

■ j It is found that with the binder according to the invention produced cores without the use of a shaking device and without the supply of external mechanical energy disintegrate and flow out of the casting. In the case of omitting the inventive Binder had to be used a shaker to shake out the amount given above to achieve.

Example 25

• jQ By propoxylating 1.0 mol of ethylenediamine with 8.0 mol Propylene oxide is an amine polyol made. A 50 percent solution of the amine polyol is prepared in 50% of a solvent mixture, Consists of 30% isophorone, 16.5% of a common aromatic solvent and 3.5% kerosene.

Part I is obtained.

It is a 75 percent solution of a polyisocyanate based on Mondur MR using 25% of a solvent mixture which consists of 19% of an aromatic solvent (Texaco 7545) and 6% kerosene.

The isocyanate solution is part II. An approximately stoichiometric amount of the polyisocyanate is used to achieve a to achieve complete reaction of the hydroxyl groups of the polyol.

According to Examples 17 to 21, the sand mentioned in Example 1 is mixed with parts I and II. The amount of binder (Part I and Part II in equal amounts) is 1-1 / 2%, based on the weight of the sand.

According to Example 16, test specimens are produced from the molding compound. Curing takes place with trimethylamine, the test specimens being gassed for about 10 seconds and then remaining in the core box for a dwell time of 5 minutes before they are removed therefrom. The tensile strengths are 5.62 kg / cm ² 15 minutes after gassing and 9.49 kg / cm ² after 24 hours.

909881/0655

The test specimens obtained are used as in Example 1 as cores when casting aluminum. Then the Shake out test carried out according to Example 1.

It turns out that the cores produced with the binder according to the invention disintegrate without the use of a shaking device and without the supply of external mechanical energy and flow out of the casting. The amount to be extracted is 100%.
10

Example 26

A 58.5 percent solution of a phenolic polyol (commercially available as PEP resin) in HISOL 10 is prepared. You get part I.
15th

In addition, a 75% solution of a polyisocyanate based on Mondur MR in 25% of a solvent mixture is used made of 19% aromatic solvent (Texaco 7545) and 6% kerosene. The isocyanate solution represents Part II. An approximately stoichiometric amount of the polyisocyanate is used to to achieve complete reaction of the hydroxyl groups of the polyol.

According to Example 1, the sand mentioned there is mixed with parts I and II. It becomes the binder (equal amounts of Part I and Part II) in an amount of 1.8%, based on the weight of the sand, used.

According to Example 16, test specimens are produced from the molding compound obtained and are cured by gassing with dimethylethylamine in a mixture with carbon dioxide. The test specimens are exposed to the catalyst for about 1 second and then immediately removed from the core box. The tensile strengths are 12.8 kg / cm ² immediately (1 minute) after removal

2 would take from the core box, 15.8 kg / cm ² after 4 hours and 20.8 kg / cm 2 after 20 hours.

^L 909 8 81/0655

The test specimens obtained are used as in Example 1 as cores when casting aluminum. Then takes place the shake-out test according to the example

It turns out that the cores after the treatment on the shaker cannot be shaken out. The amount shaken out is 0%.

909881/0655

Claims (1)

VOSSIUS · VOSSIUS · HILTL. · TALJCHNER · HEUNEMANN PATENT LAWYERS SI E BERTSTRAS S E 4 8OOO MONKS 86. PHONE: (OS9) 474Ο75 CABLE: B E N Z O LPATEIMT MDNCHEN -TELEX 5-29 45 3 VOPATWqQ O O 1 O u.z .: P 204 (Hi / kä) '7 J UN 1979 Case: 4016-4132 ASHLAND CHEMICAL COMPANY
Columbus, Ohio, V.St.A.
10 "Binder for molds for casting light metals" Priority: June 14, 1978, V.St.A., No. 915 413 15 June 14, 1978, V.St.A.-, No. 915 630 Claims 1 binders for molds for casting light metals, characterized by a content of an aromatic amine polyol, which by adding a liquid Polyisocyanate component cured in the presence of a tertiary amine which is gaseous at room temperature as a catalyst can be. 2. Binder according to claim 1, characterized in that the aromatic amine polyol is a reaction product of a, aromatic amine and an alkylene oxide. 3. Binder according to claim 2, characterized in that that the aromatic amine is aniline. 4. Binder according to claim 2, characterized in that the aromatic amine is an adduct of aniline and Represents formaldehyde. L 909881/0656 " \ 5. Binder according to claim 2, characterized in that the alkylene oxide is propylene oxide. 6. Binder according to claim 2, characterized in that the alkylene oxide is ethylene oxide. 7. Binder according to claim 2, characterized in that the amine polyol is in the form of an aqueous solution. 8. Binder according to claim 2, characterized in that the amine polyol is in the form of a solution in an organic solvent. 9. Binder according to claim 8, characterized in that that the organic solvent is an aromatic organic solvent. 10. Binder for molds for casting light metals, characterized by a content of an adduct from ammonia and an alkylene oxide containing amine polyol, which by adding a liquid polyisocyanate component in The presence of an amine which is gaseous at room temperature can be cured as a catalyst. 11. Binder according to claim 10, characterized in that the amine polyol is in the form of an aqueous solution. 12. Binder for molds for casting light metals, characterized by a content of an aromatic amine polyol, which can be cured by adding a liquid polyisocyanate component. 13. Binder according to claim 12, characterized in that the aromatic amine polyol is a reaction product of a an aromatic amine and an alkylene oxide. 909881/0655 , 14. Binder according to claim 13, characterized in, that the aromatic amine is aniline. 15. Binder according to claim 13, characterized in that that the ar < represents. _K that the aromatic amine is an adduct of aniline and formaldehyde 16. Binder according to claim 13, characterized in that the alkylene oxide is propylene oxide. 17. Binder according to claim 13, characterized in that that the alkylene oxide represents ethylene oxide. 18. Binder according to claim 13, characterized in that the amine polyol is in the form of an aqueous solution. 19. Binder according to claim 13, characterized in that that the amine polyol is in the form of a solution in an organic solvent. 20. Binder according to claim 13, characterized in that that the amine polyol in an aromatic organic solvent is present. 21. Binder according to claim 13, characterized in that that it contains a liquid or solid catalyst for urethane formation. 22. Binder for molds for casting light metals, characterized by a content of an adduct from 3Q Ammonia or an amine polyol containing alkylene oxide, which is cured by adding a liquid polyisocyanate can. 23. Binder according to claim 22, characterized in that that the amine polyol is in the form of an aqueous solution. 909881/0655 24. Binder according to claim 22, characterized in that
that it contains a solid or liquid catalyst for urethane formation. 25. Method of making molds for casting
Light metals, characterized in that one a) by mixing a molding material with a maximum of 10%, based on the weight of the molding material, of an amine polyol containing Using a binder and a liquid polyisocyanate component to produce a molding compound, b) the molding compound is shaped into the desired foundry shape and c) the foundry mold is treated with a tertiary amine which is gaseous at room temperature until the binder has cured. 26. The method according to claim 25, characterized in that the amine polyol is a reaction product of an aromatic Amine and an alkylene oxide. 27. The method according to claim 26, characterized in that the amine polyol is a reaction product of an aromatic Amine and propylene oxide are used. 28. The method according to claim 26, characterized in that the amine polyol is a reaction product of an aromatic Amine and ethylene oxide are used. 29. The method according to claim 26, characterized in that the amine polyol is used in the form of an aqueous solution. 30. The method according to claim 26, characterized in that the amine polyol is a reaction product of aniline and a Alkylene oxide is used. 31. The method according to claim 26, characterized in that the amine polyol is a reaction product of an aniline 909881/0655 Formaldehyde adduct and an alkylene oxide is used. 32. The method according to claim 26, characterized in that that one organisehen the amine polyol in the form of a solution in one Solvent uses. 33. The method according to claim 26, characterized in that that the amine polyol is used in the form of a solution in an aromatic organic solvent. 34. The method according to claim 26, characterized in that that the amine polyol is a reaction product of an aliphatic Amine and an alkylene oxide. 35. The method according to claim 34, characterized in that the amine polyol is a reaction product of an aliphatic Amine and propylene oxide are used. 36. The method according to claim 34, characterized in that that the amine polyol is a reaction product of an aliphatic Amine and ethylene oxide are used. 37. The method according to claim 34, characterized in that the amine polyol is used in the form of an aqueous solution. 38. The method according to claim 34, characterized in that that a reaction product of ethylene diamine and an alkylene oxide is used as the amine polyol.
30th 39. The method according to claim 34, characterized in that that the amine polyol is used in the form of a solution in an organic solvent. 40. The method according to claim 34, characterized in that the amine polyol is in the form of a solution in an aromatic uses organic solvents. _L. 9 09881/0655 _, 41. The method according to claim 34 _# characterized in that the amine polyol is a mixture of an aliphatic and
an aromatic amine polyol. 42. The method according to claim 34, characterized in that the amine polyol is used together with an amine-free polyol. 43. The method according to claim 42, characterized in that the amine-free polyol is a phenolic resin of the general
formula uses, in which R is a hydrogen atom or one in the m-position represents phenol substituents standing to the hydroxyl group of the phenol and m and η denote numbers, their sum is at least 2, and the ratio of m to the number of hydrogen atoms is at least 1. 44. Method of making molds for casting
Light metals, characterized in that one a) by mixing a molding material with a maximum of 10%, based on the weight of the molding material, of an amine polyol Using a binder and a liquid polyisocyanate component to produce a molding compound, b) the molding compound is shaped into the desired foundry shape and c) the foundry mold can be hardened. 909881/0655 45. The method according to claim 44, characterized in that the amine polyol is a reaction product of an aromatic Amine and an alkylene oxide. 46. The method according to claim 45, characterized in that the amine polyol is a reaction product of an aromatic Amine and propylene oxide are used. 47. The method according to claim 45, characterized in that the amine polyol is a reaction product of an aromatic Amine and ethylene oxide are used. 48. The method according to claim 45, characterized in that the amine polyol is used in the form of an aqueous solution. 49. The method according to claim 45, characterized in that the amine polyol together with a liquid or solid
Catalyst used to form urethane. 50. The method according to claim 45, characterized in that the amine polyol is a reaction product of aniline and a Alkylene oxide is used. 51. The method according to claim 45, characterized in that the amine polyol is a reaction product of an aniline-formaldehyde Adduct and an alkylene oxide is used. 52. The method according to claim 45, characterized in that the amine polyol is in the form of a solution in an organic Solvent uses. 53. The method according to claim 45, characterized in that the amine polyol is in the form of a solution in an aromatic uses organic solvents. 909881/0655 54. The method according to claim 44, characterized in that the amine polyol is a reaction product of an aliphatic Amine and an alkylene oxide. 55. The method according to claim 54, characterized in that the amine polyol is a reaction product of an aliphatic Amine and propylene oxide are used. 56. The method according to claim 54, characterized in that a reaction product of an aliphatic amine and ethylene oxide is used as the amine polyol. 57. The method according to claim 54, characterized in that the amine polyol is used in the form of an aqueous solution. 58. The method according to claim 54, characterized in that the amine polyol is used together with a liquid or solid catalyst for urethane formation. 59. The method according to claim 54, characterized in that the amine polyol is a reaction product of ethylenediamine and an alkylene oxide is used. 60. The method according to claim 54, characterized in that the amine polyol is used in the form of a solution with an organic solvent. 61. The method according to claim 54, characterized in that the amine polyol is in the form of a solution with an aromatic uses organic solvents. 62. The method according to claim 44, characterized in that the amine polyol is a mixture of an aliphatic and
an aromatic amine polyol. 63. Use of the molds obtained by one of the methods according to claims to 62 for casting light metals. ^L 909881/0655 ^J.