Curing agent for water glass molding and manufacturing method and use thereof

Abstract

A curing agent for water glass molding comprises: ester; amorphous silica; and water. The amorphous silica is formed by means of a pyrolysis method and/or by means of a precipitation method. Also disclosed is a use of the curing agent for water glass molding in preparation of a casting mold and a mold core. Respective components of the curing agent comprising ester, amorphous silica and water are mixed at a high speed to form a suspension. Next, the suspension is applied to prepare a water glass self-hardening sand. The curing agent does not cause powder contamination, and can be measured and added conveniently. Also disclosed are a manufacturing method of the curing agent for water glass molding and a water glass self-hardening sand.

Claims

1. A curing agent for casting water glass comprising 20-30% of an ester, 40-60% of an amorphous silica; 6-12% of an alcohol; and 10-18% of water by mass fraction; wherein the amorphous silica is a pyrogenic amorphous silica and/or a precipitated amorphous silica; wherein the ester is any one selected from a group consisting of glyceryl monoacetate, glyceryl diacetate, glyceryl triacetate, ethylene glycol diacetate, propylene carbonate, dibasic esters, and a mixture of at least two thereof; wherein the alcohol is any one selected from a group consisting of ethanol, methanol, propanol, isopropanol, butanol, isobutanol, benzyl alcohol, ethylene glycol, polyethylene glycol, and a mixture of at least two thereof.

2. The curing agent according to claim 1, wherein the alcohol is ethanol.

3. A method for preparing the curing agent for casting water glass according to claim 1, comprising the following steps: (1) first, adding the ester weighed according to the mass fraction into a stirring tank of a high-speed mixer and stirring; (2) inputting the water weighed according to the mass fraction, and inputting the alcohol weighed according to the mass fraction; adjusting rotation speed to 800 rpm or more, and then adding the amorphous silica, and stirring for 10-20 minutes to form a suspension to obtain the curing agent for casting water glass.

Description

DETAILED DESCRIPTION

(1) In order to facilitate the understanding of the present invention, the following examples are exemplified in the present invention. It should be understood by those skilled in the art that the examples are only to facilitate the understanding of the present invention and should not be construed as specific limitations to the present invention.

Example 1

(2) TABLE-US-00001 Components ratios (mass/g) glyceryl diacetate 30 ethylene glycol diacetate 60 glyceryl triacetate 300 propylene carbonate 10 silicon micropowder 600 ethanol 30 water 50

(3) Preparation Process

(4) 1. Glyceryl diacetate, ethylene glycol diacetate, glyceryl triacetate and propylene carbonate were weighted and added into a stirring tank of a high-speed mixer and stirred for 60 min;

(5) 2. Ethanol and water were added, the stirring speed was adjusted to 900-1100 rpm, then silicon micropowder was added, and the mixture was stirred for another 10 min to obtain a liquid enhancer a for water glass self-hardening sand (i.e., the curing agent for casting water glass of the present invention).

Example 2

(6) (1) The components are compounded according to Example 1, except that ethanol was replaced by methanol;

(7) (2) The preparation process was the same as that in Example 1.

Example 3

(8) (1) The components are compounded according to Example 1, except that ethanol was replaced by propanol;

(9) (2) The preparation process was the same as that in Example 1.

Example 4

(10) (1) The components are compounded according to Example 1, except that ethanol was replaced by isopropanol;

(11) (2) The preparation process was the same as that in Example 1.

Example 5

(12) (1) The components are compounded according to Example 1, except that ethanol was replaced by butanol;

(13) (2) The preparation process was the same as that in Example 1.

Example 6

(14) (1) The components are compounded according to Example 1, except that ethanol was replaced by benzyl alcohol;

(15) (2) The preparation process was the same as that in Example 1.

Example 7

(16) (1) The components are compounded according to Example 1, except that ethanol was replaced by ethylene glycol;

(17) (2) The preparation process was the same as in that Example 1.

Example 8

(18) (1) The components are compounded according to Example 1, except that ethanol was replaced by polyethylene glycol;

(19) (2) The preparation process was the same as that in Example 1.

Example 9

(20) (1) The components are compounded according to Example 1, except that no ethanol was added;

(21) (2) The preparation process was the same as that in Example 1.

(22) The liquid enhancers for water glass self-hardening sand as prepared in Examples 1-9 were tested for their stability, and the results were shown in Table 1.

(23) TABLE-US-00002 TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Stability 99% 83% 78% 81% 83% 92% 85% 84% 90%

(24) Stability test standard: Refer to JB/T5107-91 “Coatings for Sand Casting”

(25) Operation Steps

(26) A representative curing agent sample was poured into a dry graduated cylinder to a level of 100 ml. The sample was specifically left in a static state for 5 h according to the detection requirements for different types of curing agents. The area of the clear layer was red, correct to 1 mL.

(27) $\mathrm{Calculation}\mathrm{Result}$$C=\frac{100-V}{100}\times 100\%$

(28) wherein:

(29) C—suspending rate of the curing agent, %

(30) V—the area of the clear layer on the upper part of the curing agent column in the graduated cylinder, ml

(31) It was shown in table 1 that the suspension of the curing agent was allowed to be more stable in Example 1 in which case ethanol was used as an organic solvent compared to Examples 2-8; and the prepared liquid enhancers were allowed to form suspensions with stronger stability in Examples 1-8 in which cases alcohol solvents were added compared to Example 9.

Example 10

(32) TABLE-US-00003 Components ratios (mass/g) glyceryl diacetate 37.5 ethylene glycol diacetate 75 glyceryl triacetate 375 propylene carbonate 12.5 silicon micropowder 500 ethanol 60 water 20

(33) Preparation Process

(34) 1. Glyceryl diacetate, ethylene glycol diacetate, glyceryl triacetate and propylene carbonate were weighted and added into a stirring tank of a high-speed mixer and stirred for 60 min;

(35) 2. Ethanol and water were added, the stirring speed was adjusted to 900-1100 rpm, then silicon micropowder was added, and the mixture was stirred for another 10 min to obtain a liquid enhancer b for water glass self-hardening sand (i.e., the curing agent for casting water glass of the present invention).

Example 11

(36) (1) The components are compounded according to Example 10, except that the addition amounts of the ester components were adjusted according to the followings;

(37) TABLE-US-00004 glyceryl diacetate 30 ethylene glycol diacetate 70 glyceryl triacetate 400

(38) (2) The preparation process was the same as that in Example 10, and a liquid enhancer c for water glass self-hardening sand (i.e., the curing agent for casting water glass of the present invention) was obtained.

(39) The liquid enhancers for water glass self-hardening sand obtained from Examples 1 and 10-11 were used in preparing water glass self-hardening sand, with the following specific operations:

(40) 1000 g of standard sand from Dalin was weighted and added into a blade sand mixer for use in laboratory, 8.64 g of the liquid enhancer for water glass self-hardening sand was added, and the mixture was stirred for 1 min, 20 g of water glass SQ-1 was added, and stirred for 1 min, then the sand was produced, and a standard “8”-shaped test cube was made and tested for tensile strength at 1 h, 4 h and 24 h, and the results were shown in Table 2.

Comparative Example 1

(41) (1) The components are compounded according to Example 1, except that no silicon micropowder, ethanol and water were added;

(42) (2) The preparation process was the same as that in Example 1.

Comparative Example 2

(43) (1) The components are compounded according to Example 10, except that no silicon micropowder, ethanol and water were added;

(44) (2) The preparation process was the same as that in Example 10.

Comparative Example 3

(45) (1) The components are compounded according to Example 11, except that no silicon micropowder, ethanol and water were added;

(46) (2) The preparation process was the same as that in Example 11.

(47) The organic esters obtained from Comparative Examples 1-3 were used in preparing water glass self-hardening sand, with the following specific operations:

(48) 1000 g of standard sand from Dalin was weighted and added into a blade sand mixer for use in laboratory, 7.5 g of organic ester SG-25 was added, and the mixture was stirred for 1 min, 30 g of water glass SQ-1 was added, and stirred for 1 min, then the sand was produced, and a standard “8”-shaped test cube was made and tested for tensile strength at 1 h, 4 h and 24 h according to the Executive Standard GB-2684, and the results were shown in Table 2.

(49) TABLE-US-00005 TABLE 2 Tensile Strength (MPa) NO. 1 h 4 h 24 h Ex. 1 0.410 0.553 0.596 Comp. Ex. 1 0.279 0.476 0.483 Ex. 10 0.402 0.540 0.586 Comp. Ex. 2 0.309 0.513 0.527 Ex. 11 0.394 0.512 0.605 Comp. Ex. 3 0.300 0.497 0.535

(50) By comparing Examples 1, 10-11 with Comparative Examples 1-3, respectively, it was shown that in Examples 1, 10-11, the organic ester components, which were incorporated with silicon micropowder, were used to formulate the liquid enhancer for water glass self-hardening sand to prepare water glass self-hardening sand, which had a significant improvement on tensile strength. The strength of the water glass self-hardening sand can be significantly increased after molding for 1 h. The strength of the water glass self-hardening sand prepared therefrom still remained at a relatively high level even after storage for a long time after molding. Thus, the mechanical properties of the casting mold and the mold core were greatly improved.

Example 12

(51) TABLE-US-00006 Components ratios (mass/g) glyceryl monoacetate 90 glyceryl triacetate 300 propylene carbonate 10 silicon micropowder 600 methanol 30 water 50

(52) The preparation process was the same as that in Example 1.

Example 13

(53) TABLE-US-00007 Components ratios (mass/g) glyceryl triacetate 300 propylene carbonate 100 silicon micropowder 600 propanol 30 water 50

(54) The preparation process was the same as that in Example 1.

Example 14

(55) TABLE-US-00008 Components ratios (mass/g) propylene carbonate 400 silicon micropowder 600 butanol 30 water 50

(56) The preparation process was the same as that in Example 1.

Example 15

(57) TABLE-US-00009 Components ratios (mass/g) propylene carbonate 400 silicon micropowder 600 water 80

(58) The preparation process was the same as that in Example 1.

Example 16

(59) TABLE-US-00010 Components ratios (mass/g) ethylene glycol diacetate 112.5 glyceryl triacetate 375 propylene carbonate 12.5 silicon micropowder 500 ethanol 60 water 20

(60) The preparation process was the same as that in Example 1.

Example 17

(61) TABLE-US-00011 Components ratios (mass/g) glyceryl diacetate 60 glyceryl triacetate 410 silicon micropowder 500 methanol 60 water 20

(62) The preparation process was the same as that in Example 1.

Example 18

(63) TABLE-US-00012 Components ratios (mass/g) glyceryl triacetate 470 silicon micropowder 500 propanol 60 water 20

(64) The preparation process was the same as that in Example 1.

(65) The liquid enhancers for water glass self-hardening sand obtained from Examples 12-18 were used in preparing water glass self-hardening sand, with the following specific operations:

(66) 1000 g of standard sand from Dalin was weighted and added into a blade sand mixer for use in laboratory, 8.64 g of the liquid enhancer for water glass self-hardening sand was added, and the mixture was stirred for 1 min, 20 g of water glass SQ-1 was added, and stirred for 1 min, then the sand was produced, and a standard “8”-shaped test cube was made and tested for tensile strength at 1 h, 4 h and 24 h. Through the texting, the strength of the water glass self-hardening sand prepared by using the liquid enhancer for water glass self-hardening sand prepared therefrom was significantly increased after molding for 1 h, and the tensile strength was 0.395-0.408. The strength of the water glass self-hardening sand prepared therefrom still remained at a higher level even after storage for a long time after molding. After molding for 24 h, the tensile strength thereof could reach 0.586-0.605, greatly improving the mechanical properties of the casting mold and the mold core.

(67) In addition, in the present invention, each component of the curing agent comprising an ester, an amorphous and water is subjected to high-speed shearing and mixing to formulate a slurry, which is then used in the preparation of water glass self-hardening sand, thereby a one-time addition of the curing agent for casting water glass is achieved without powder pollution. The operations are simple, the measurement, addition and application are convenient, and an industrial production is achieved.

(68) The Applicant states that the present invention illustrates the detailed process equipment and process flow of the present invention by the above embodiments, however, the present invention is not limited to the above detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above detailed process equipment and process flow for implementation. It should be apparent to those skilled in the art that any modifications of the present invention, equivalent substitution of the various materials of the products of the present invention, addition of auxiliary components, selection of specific means, and the like, are all within the protection scope and disclosure scope of the present invention.