SU552894A3 - Mixture for the manufacture of casting molds and cores and the method of their curing - Google Patents

Description

(54) MIXTURE FOR THE MANUFACTURE OF CASTING FORMS AND RODS AND A METHOD FOR THEIR CURING OF TEYNI workshops due to the toxicity and explosion hazard of this reagent. In addition, it is desirable to further increase the speed of curing of the forms and rods in comparison with the known technological option. The aim of the invention is to increase the viability and cure rate of the mixture and to improve the sanitary and hygienic working conditions in the molding and core sections of foundries. To achieve this goal, the mixture for making casting molds and cores, including refractory filler, polyester binder and hardener, contains acrylic or methacrylic acid ester as a binder, and a catalytic agent, namely, hydroperoxide with the general formula NUON, a monovalent organic radical as a binder. containing from 1 to 18 carbon atoms, in combination with a curing accelerator - a reagent selected from the group of compounds of polyalkylenepolyamine and polycaptan, in the following ratio AI ingredients weight. h .: Refractory filler 0.5-10.0 Binder 0.00005-1.5 Catalyst 0.005-1.0 Curing Accelerator Achieving this goal is a method of curing molds and cores from the described mixture, including the purging of the mixture with gas, which is characterized by the fact that oxygen is removed from the mixture during its purging process by displacing it with an inert gas, namely nitrogen, followed by coating the molds and rods with an air-tight film. The curing mechanism of the mixture in accordance with the invention is as follows. The structure of monomeric acrylate esters, which are part of the binder, contains free reactive radicals. The latter interact with the oxygen of the air and are blocked by it. Consequently, the oxygen of the air acts as a polymerization inhibitor. When oxygen from the system is removed from the system, for example, when it is displaced with an inert gas (nitrogen), free radicals in the presence of a catalyst and a curing accelerator initiate the polymerization reaction, which leads to irreversible curing of the binder and, accordingly, containing this binder mixture. Such binders are classified as anaerobically curable, i.e., curable in an oxygen-free environment. It can be seen from the above explanation that, in contrast to the known methods of curing mixtures based on purging with a gas reagent that is an active participant in the chemical curing reaction, the proposed inert gas does not have a direct role in the curing reaction, but oxygen displaced provides for its active flow. The term "inert gas" means in this case such a gaseous or vaporous substance that does not inhibit the curing process of the binder. In accordance with the invention, the following compounds can be used as a binder, an acrylic or methacrylic acid ester: a) CH, --- CR - CO — O (CH,) - (CHRO, -RCHO - -, CO -CR.CH, (I), where a is a positive integer from 1 to 8, b is a positive integer from 1 to 20, c is O or 1, R is hydrogen, methyl, ethyl, hydroxymethyl or the group -CHaO- CO-CRi CH2; R is hydrogen, hydroxyl or the group -OCO-CRi CH2. R is hydrogen, chlorine, methyl or ethyl; b) JCH, -CR-CO-0-1-CH,), - (CRR - 0- -bje-R (R), where b and c have the values defined in the previous paragraph a; d-0 or a positive integer, provided that c and of not equal to 0; e is a positive integer from 1 to 4; R1 and R2 are defined in the preceding paragraph a; R is an organic radical of valency e, bonded by a carbon atom, I. OR the carbon atoms of its chain to oxygen atoms in the groups indicated in square brackets with the index b; V CHs-CR -CO-O-CH-CHOH / CH, -0 - (- CO) e- -eR% (III), where these have the meanings defined, respectively, in paragraphs a and b; R is hydrogen or methyl; R is the organic radical of valency e, bonded to ether through its carbon atom other than the carbon atom of the carbonyl group; (CH., CR-CO-O-R-X), R de R is defined in paragraph a; R is a bivalent aliphatic, cycloaliphatic, aromatic, or araliphatic adduct, bound by its carbon atom or carbon atoms to an atom or group designated -O-li -X-; X is oxygen or a group —N (R), de R is hydrogen or an alkyl radical containing from 1 to 8 carbon atoms; g is a positive positive number equal to at least 2, but not exceeding 6; R is a valence g of an aliphatic, cyclolyphatic, aromatic, or araliphical radical linked by

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its carbon atom or carbon atoms with the NH groups indicated in the diagram;

) CH -Cfi -co-o-CHj-CHOHCH, -: N-R - -it) j (V).

CHj CR -co-o-g W with, - SNON-CH j-fN-R) h

where R is defined in paragraph a; R is hydrogen or an alkyl radical containing from 1 to 6 carbon atoms with possible substitution by cyano, hydroxyl or group

CH2 - CR1-CO-O-CHg-CHOH-CHg-; R® is a bivalent aliphatic, aromatic, heterocyclic or cycloaliphatic residue containing from 1 to 10 carbon atoms and linked through its carbon atoms to nitrogen atoms: h-O or a positive integer from 1 to 3; / -O or h.

Preferred is the use of compounds corresponding to general feeds (I-V), with the following structural features:

0 1. L 2-5, with 0, R and R - hydrogen or methyl (see general formula I);

,, d, R1 is hydrogen or methyl, R is the hydrocarbon radical of an aliphatic alcohol, the molecules of which contain from 1 to 6 carbon atoms. in particular, methyl or gppuppa of formula C (CH2-) 4 (see general formula II);

 (ppi provided, if c is 0) -containing from 1 to 18 carbon atoms, the residue of alcohol or phenol, the molecules of which contain e of the horny groups, nappimeo-SwNc and -C-W.CHo. if in. -C.H4C (CH3) 2SbN4- and -C-HiCHoCeH - if е 2,

I

Sbn (СНйСбНз), -СНрСбН4-, gle f - 1 or 2. if е 3 or 4. and also aliphatic groups СН2СНСН - or

I (СН.) ÑНН-, if, - (СН,) -,

I

- SNSN-. -CHoCHsOCHoCHs- or - (CHoCH2OUCH2CH-, if, - (CH.). CH3, --HSN) LH, -CH2CH CH2 or CfbCH CHCH20H,

R (CONDITIONS, if) is a residue of an acid containing from 1 to 60 carbon atoms, the molecules of which contain e hydroxyl groups. For example, -CH3, -CH2CH3,

-CH SNGON SNZ, -CH, C1 and -SbNc, if s-1. --CHnCHj-. -CH-CH- and -CbH4-, ((see general formula III);

R - two-valent aliphatic radikp .h. containing from 2 to 6 carbon atoms, and R - can be a divalent aromatic oatic with a number of carbon atoms from 2 to 10, for example - (CH2) b-,

СН, С (СНз) pСНоСН (СНз) (СН2) 2-

or

-CHACH (CH3) CH2C (CH3) 2 (CHg) g-,

6

phenyl radical with possible substitution by a methylene group or a chlorine atom, a naphthalene radical, radicals

-C5H4C5N4-, C5H4CHN2SeH4-or

 (CH3) 2C5H4-,

a monocyclic, alkylcycloalkylene or alkylcycloalkylalkylene radical containing from 6 to 10 carbon atoms, in particular methylcyclohex-2,4-ylenmethyl, methylcyclohex-2,6-ylenmethyl or 1,3,3-trimethylcyclohex-5-ylemethyl radical (see formula IV):

R is an isopropyl radical; R is an ethylene, propylene or i-propylene group (see general formula V).

The group of organic hydroperoxides, which can be used as polymerization catalysts, includes compounds of the general formula, where R is a monovalent organic radical, containing up to 18 carbon atoms, in particular, alkyl, aryl or apalkyl radical. containing from 4 to 13 carbohydrate atom. Typical hydroperoxides are ethylmethylketone and peroxide, tertiary butyl hydroperoxide, cumene hydroperoxide and hydroperoxide, obtained by oxidizing cetin or piclohexane with oxygen, and tertiary butyl hydroperoxide and cumene hydroperoxide are particularly effective. Hydrogen peroxide can also be used. use for the same purpose

a rich variety of organic peroxides, in particular 2,5-dimethyl-2,5-di (treg-butylperoxy) hexene, di-tert-butyl peroxide, dihexylene glycol peroxide, heats, butyl cumyl peroxide, isobutyl methyl ketone, and esters

peracids, in particular tert, butyl percetate, toet, butyl perbenzoate and tert, butyl perphthalate.

Accelerator group includes polyalkyleipolyamine, specific

examples of which are diethylene phosphate and triethylene tetramine: polyisopylates, in particular toluene-2,4-diisocyanate: aldimines; tertiary amines, in particular M, K-dimethylbenzylamine and triethylamine; imides and sulSmyls. in particular, o-benzoic sulfimide; dithiocarbamates; amypes and thiomides, in particular formamide; thiazole. in particular, 2-mercaptobenzthiazole: ascorbic acid: organic phosphates; quaternary amine sols and bases: transition metal salts: thiourea. as well as polymercaptans, in particular, mercaptancarboxylic acid esters, in particular Tris glycerol (thioglycol t). Especially preferred

Polymercaptans and polyalkylene compounds are thiamines, and the acceleration effect on thialkylene polyamines can often be enhanced by introducing into a smaller than stoichiometric amount of monocarboxylic acid, alkanoic and alkanoic acid, in particular, n-enanthic acids and acrylic acids, which are particularly suitable.

The lower limits on the content in the composition of the mixture are bonded; its catalyst and curing accelerator are selected, based on the condition of obtaining the lowest possible rate of cold curing and the strength of the forms and rods, the upper limits of the indicated ingredients are chosen based on. economic considerations.

The preferred binder content in the mixture is 1-5 wt. hours, the catalyst is 0.005-1.0 weight. hours, the curing accelerator - 0.005-1.0 weight. h

Polymerization inhibitors can be added to the binder, for example, quinones or hydroquinones in an amount of from 0.001 to 0.1% by weight of the binder, as well as diluents that reduce the viscosity of the binder.

For the preparation of the molding mixture, the known displacement aggregates, in particular continuous mixers with the unloading of the finished mixture, are indisputably integrated in the tooling.

It is advisable to preliminarily displace the refractory filler (for example, quaicane sand) separately with the binder and separately with the talizatoi, and then immediately before making the molds and the steps, peesmesh them with each other. In this case, the curing hardener can be introduced either into the mixture of sand and binder, or into the mixture of sand and catalyst.

Dispensing of the finished mixture, compacted in the usual way in fire condition pishitit in beskis.log1odnoy Soede. This gas is displaced from the air mixture by blowing it with gas or steam that does not inhibit the curing of the binder. Nitrogen is the most suitable gas, but the same gas can also be achieved by evacuating the mold or rod. To keep the shape or stand in the no-medium environment for at least 10 minutes, in order to keep the mixture deep enough. Air infiltration into the mold or rod during its curing can be prevented by covering them with an air-tight film immediately after stopping the purging with an inert gas.

The application of the heating of the mixture also makes it possible to intensify the curing of the mixture and shorten the duration of lodging of the chopm or rod in an oxygen-free environment. The mixture can be heated by preheating an inert gas, in particular nitrogen. In accordance with another embodiment, the mixture is heated by a dielectric substance, that is, using radio frequency current. Preferred heating mode: temperature 40-350 ° С (50-150 ° С), duration 0.5-10 min (1-3 min).

The invention is illustrated by the following examples.

Example 1. Example 1 contains specific names for binders based on acrylic or methacrylic acid esters, and also describes how to obtain them briefly (products L. C. C. D, E, F, G, H, 1, one.

Molding mixtures with the indicated products (binders) will be described in the following examples.

The epoxy equivalent of the binder was determined by titration with 0.1-n. a solution of perchloric acid in acetic acid in the presence of an excess of tetrachlorammonium bromide, and crystal violet (crystal-violet) was used as an indicator, Product A.

It is mainly 1,4-bis (2-hydroxy-3-methacryloyloxypropoxy) -butane, which is obtained by displacing 67 g of methacrylic acid, 1 g of triethylamine and 0.1 g of hydroquinone at 120 ° C in a flask equipped with a reflux condenser. , with 100 g of butane-1,4diol diglycidyl ether (epoxy equivalent of 7.8 eq / kg) for 1 hour and additionally moving at 120 ° C for another 1 hour, resulting in an epoxy equivalent dropping to 0. Product B.

It is practically 1- (2oxy-3-methacryloyloxypropoxy) -butane, which was obtained in a similar way using 60.6 g of methacrylic acid and 100 g of p-butylglycidyl ether (epoxy equivalent of 7.05 eq / kg) in the presence of and 2 g of triethylamine and 0.1 g of hydroquinone. Product C.

A mixture of 30 g of adipic acid, 58.2 g of glycidyl methacrylate, 1 g of triethylamine and 0.1 g of hydroquinone was kept at 120 ° C for 2.5 hours, moving in a flask equipped with a reflux condenser.

Product C is predominantly bis- (2-hydroxy-3 - meta-apployl-oxypropyl) -adipate. If the epoxy equivalent is 0. Product D.

It is mainly 2-hydroxy-3 - methacryloyloxypropyl propionate (glycerol methacrylate propionate), which is obtained by heating at 120 ° C with stirring a mixture of 50 g of glycidyl methacrylate with 26 g of propionic acid, 0.7 g of triethylamine and 0.06 g of hydroquinone for 2.5 hours, and the epoxy equivalent of the product is 0.

Product E.

It is a tetraplenglepcol diacrylate. Product F.

It is a tetraethylene glycol bis (methacrylate). Product G.

In a mixture of 61 g of methacrylic acid and 0.2 g of hydroquinone and 2 g of tpiethylampa, a mixture of 80 g of butane-1,4-di-diglycidyl ether was introduced during 1 hour at a temperature of 120 ° C (epoxy equivalent is 7.7 eq / kg) and 20 g of epoxy novolac resin (epoxy equivalent of 5.48 eq / kg), which was a polyglycidyl ether of phenol-formaldehyde novolak, the average molecular weight of which was 420. This mixture was stirred at

SNS OH

1I

CH2 SSOOCH2, SC01CO

where m is a positive integer, the average value of which is 2.07.

Product ya

In 87 g of toluene diisocyanate (a mixture of 2,4- and 2,6-isomers), 65 g of 2-hydroxyethyl methacrylate was added with stirring. An exothermic reaction proceeded, and the temperature was allowed to rise for 10 minutes.

CH5, CCOOCH2CH200CNH

sn.

product /.

It is 1,1,1-trimethylolpropane-tris (methacrylate).

Product /.

Mix the product A (166 g) in 300 g of toluene at 65 ° C dropwise within 30 minutes. added 16 g of methacryloyl chloride. This mixture was further stirred for 2 hours, after which the solvent was removed under reduced pressure. The product / is a mixture of 1,4-bis- (2-hydroxy-3-methacryloyloxypropoxy) -butane with 1-2,3-bis (methacryloyloxy) -propoxy-4- (2-hydroxy-Zmetacryloyloxypropoxy) -butane and 1 , 4bis-2, 3 - bis- (methacryloyloxy) -butane.

PRI mme R 2. Prepared using the binder A- /, described in example 1, the molding mixtures of the following compositions: I - 90 wt. including product A, 5 wt. including cumene hydroperoxides, 5 wt. including triethylentetramine and 4900 weight. h. sand; P - 90 weight. -h product A, 5 wt. including cumene hydroperoxides,

120 ° C for another 1 hour, and after this period of time, the epoxy equivalent is reduced to 0.

Product G is a mixture of 1,4bis- (2-hydroxy-3-methacryloyloxy) -butane with poly- (3-methacryloyloxy-2-oxypropyl) ether of phenol-formaldehyde novol. Corresponding to the formula;

he snakes

OCH2SNS200SS CH4

СНз СН2 СООССН2, СНСН20

he

up to 90 ° C. After this, an additional 66 g of 2-hydroxyethyl methacrylate was added without any heating for 30 minutes. Next, 0.2 g of hydroquinone was added and the mixture was stirred at 100 ° C for 1 hour.

Product H is a mixture of 2,4 and 2,6-bis - (2-methacryloyloxy-ethoxycarbonamido-toluenes, which basically corresponds to the following, its structural formula;

SHSOOSN., CH200SS CH, 1

I}

SNS

5 wt. including triethylentetramine, 2.5 weight. h. N. enanthic acid and 5022 weight. h. sand; P1 - 90 wt. including product A, 5 wt. including cumene hydroperoxides, 5 wt. including triethylene; tramina, 2.5 weight. including methacrylic acid and 022 wt. h. sand; IV - 90 wt. including product A, 5 wt. including cumene hydroperoxides, 5 wt. including glycerol, tritioglycolta, 2.5 wt. including methacrylic acid and 5022 weight. h. sand; V - 90 wt. product in, 5 wt. including cumene hydroperoxides, 5 wt. including triethylentetramine, 2.5 weight. including methacrylic acid and 5022 weight. H. PeSka; VI - 90 wt. product including C, 5 wt. including cumene hydroperoxides, 5 wt. including triethylentetramine and 4900 weight. h. sand; VII -90 weight. including product D, 5 wt. h. hydroamide of cumene, 5 wt. including triethylentetramiy and 4900 weight. h. sand; VIII - 90 wt. including product E, 5 wt. including cumene hydroperoxides, 5 wt. including triethytetramine and 4900 weight. h. sand; IX - 90 wt. including product F, 5 wt. including cumene hydroperoxides,

5 wt. including triethylentetramine and 4900 weight. h ..

eleven

sand; X - 90 wt. including product G, 5 wt. including cumene hydroperoxides, 5 wt. including triethylentetramine and 8233 weight. h. sand; XI - 90 wt. including product G, 5 wt. including cumene hydroperoxides, 5 wt. including triethylentetramine and 4900 weight. h. sand; XII - 90 wt. including product G, 5 wt. including cumene hydroperoxides, 5 wt. including triethylentetramine and 4066 weight. h. sand; XIII 85 wt. product g, 5 weight, h, hydroperoxide

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cumene, 10 wt. including triethylentetramine and 5845 weight. h. sand, XIV - 45 wt. including product and F, 45 wt. including product H, 5 wt. including cumene hydroperoxides, 5 wt. including triethylentetramine and 5022 weight. h. sand,

The experiments used washed quartz sand, the grain composition of which is shown in Table 1,

Table I

This sand was mixed with the other ingredients of the molding mixture, with the exception of TPET or glycerol tritioglycol, after which one of them was added and the mixture was intensively mixed for several seconds. Similar results could have been obtained by first mixing sand with triethylene tetramine or gliaine tritioglycol followed by adding other ingredients.

The molding sands were poured into the tooling for the manufacture of standard cylindrical specimens (50 mm in height and diameter).

table 2

Curing was initiated by flushing nitrogen through the mixture in a snap (purge pressure 18 kM / m). The specimens were tested for compression either immediately upon completion of nitrogen purging and removal of samples from the core box.

or after additional storage of the extracted samples in a nitrogen atmosphere.

The test results are presented in Table. 2. For comparison, table. 3 shows the data

similar tests when used as a gas for purging CO2 instead of nitrogen (the purge pressure was also 18 kM / m), from which it is clear that the curing rate and strength in this case decrease by about 2 times.

Table 3

Example 3. The process described in Example 2 was repeated with the difference that immediately upon completion of the nitrogen purge, the samples were removed from the equipment and subjected to radio frequency heating (a heater was used

brand H5D / H, produced by the English firm Radio Heaters Ltd., Wokingham, Berkshire). Heating parameters: operating frequency of current 36 MHz, power 0.2 kW at the gap between the upper electrode and the test

with a sample of 0.5 cm. After heating for 2, 3, and 4 min, the temperature in the middle of the sample was 80, 90, and 110 ° C, respectively. The specimens cooled in air to room temperature (within about

30-60 MiHi), after which they were tested for compression. The results are shown in Table. four.

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Table 4

  Sign means no measurement.

Example 4. The process described in example 2 was repeated using the following molding compounds: XV - 90 wt. product /, 5 wt. including cumene hydroperoxides, 2.5 wt. including methacrylic acid, 5 wt. including triethylentetramine and 5 125 weight. h. sand; XVI - 75 wt. including product -A, 15 wt. product /, 5 wt. including cumene hydroperoxides, 2.5 wt. including methacrylic acid, 5 wt. including triethylentetramine and 5 125 weight. h. sand; XVn - 75 wt. product A, 15 wt. product /, 5 wt. including cumene hydroperoxides, 2.5 wt. including methacrylic acid, 5 wt. including triethylentetramine and 3416 weight. h. sand; XVni -82,5 weight. including product A, 7.5 wt. product /, 5 wt. including cumene hydroperoxides, 5 wt. including triethylentetramine, 2.5 weight. including methacrylic acid and 5 125 weight. h. sand; XIX - 90 wt. product /, 5 wt. including cumene hydroperoxides, 5 wt. including triethylentetramine, 2.5 weight. including methacrylic acid and 5 125 weight. h. sand.

Test specimens were removed from the rig immediately upon completion of the nitrogen purge and tested for compression. The results of the definitions are shown in Table. five.

Example 5. The process described in Example 2 was repeated using a P1 molding sand, but with nitrogen passing at a higher pressure of -36 kU / m, and the duration of nitrogen passing and exposure to nitrogen was changed.

The results of the definitions are shown in Table. 6

Example 6. The process described in example 2 was repeated using molding mixtures I and P1 with the change that nitrogen was preheated by passing through a heated steel coil tube before blowing the mixture in the equipment. At the end of the purge samples from 14

Table 5

25

Table 6

thirty

35

40

45

50

they were drawn out of the equipment and kept in air until they acquired room temperature. The test results are shown in Table. 7

Example 7. In a molding mixture P1 (for composition, see Example 2) in order to enhance the adhesive interaction of the binder with

the filler was added 2 weight, including the following silanes: 2- (3,4-eioxycyclohexyl) ethyltrimethoxysilane (mixture XX); 3- (2,3epoxypropyloxy) -propyltrimethoxysilane (mixture XXI); 3- (methacryloxy) -npropyltrimethoxysilane (mixture XXII).

Table 7

Mixtures and samples were made in the same way as in example 2.

Nitrogen was blown through the mixture in the equipment at room temperature under a pressure of 18 kM / m for 60 sec. Compressive strength was as follows: Mixture XX1126 kU / m2;

Mixture XXI1263

Mixture XXII1520 KYM

Claims (2)

1. A mixture for the manufacture of casting molds and cores, including a refractory filler, a polyester binder and a hardener, characterized in that, in order to increase its viability and cure speed, it contains acrylic or methacrylic acid ester as a binder. as a hardener, a catalyst, namely, hydroperoxide with the general formula, where R is a monovalent organic radical containing from 1 to 18 carbon atoms, in combination with a hardening accelerator with a reagent selected from the group of compounds ilenpoliamina and polymercaptan, with the following ratio of ingredients, wt. including: Refractory refill100 Binding 0,5-10,0 Catalyst0,00005-1,5 Curing accelerator 0.005-1.0 2. A method of curing molds and cores made from the mixture according to claim 1, comprising purging the mixture with gas, characterized in that, in order to increase the cure rate and improve sanitary-hygienic working conditions, oxygen is removed from its displacement with an inert gas, namely nitrogen, followed by coating the molds and rods with an airtight film. Sources of information taken into account and expertise: 1.Sb. “Works of TsNIITMASH, 1961, M., No. 24, p. 82-89. 2. The patent of France No. 2031636, B 22c 1/00, 1970.