JP2895869B2 - Organosilicon compounds and binders for foundry sand - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel organosilicon compound and a binder composition for an acid-curable molding sand, and more particularly, the present invention has an alkyl-substituted phenylenediamino group. The present invention relates to an organosilicon compound and a binder for molding sand which gives a cured product having high moisture resistance comprising the organosilicon compound and an acid-curable resin.

[Technical background of the invention and its problems]

As the binder used in the production of molds and cores, phenolic resins, furan resins, urea resins, melamine resins or modified products thereof are conventionally known, and particularly modified products with furfuryl alcohol are used in this application. Widely used.

However, these binders have various difficulties that occur during casting.

For example, when bonded with a urea resin or a urea furan resin, there is an example in which pinholes and blowholes are generated due to decomposition of the resin and gas generated at that time.

Phenolic resins are excellent in this respect, but have low practicality due to low bond strength and brittleness sometimes causing shape loss and core breakage.

If the amount of the resin added is increased to improve this, generation of a large amount of gas is inevitable, causing a bad smell, and furthermore, it is economically difficult.

It is known that the addition of a small amount of an organosilicon compound is effective in solving these difficulties.

For example, according to Japanese Patent Publication No. 43-15161, as an organosilicon compound, a general formula R ¹ Si (OR) ₃ (where R ¹ is a lower aliphatic group, a phenol resin cured with an acid, a urea resin, Those having the ability to react with active groups of melamine resin or furan resin or a mixture thereof, for example, amino group, epoxy group, mercapto group, hydroxy group, carbo-lower alkoxy group, hydroxy-lower alkylamino group such as dihydroxyethylamino, An amino lower alkylamino group such as aminoethylamino, or a lower alkenyl carboxy group such as acrylate or methacrylate, or a lower alkenyl-containing alkylene group having 2 to 6 carbon atoms such as vinyl; and R is a lower alkyl group such as methyl or ethyl. An alkyl group or a lower alkoxy lower such as methoxyethyl A mold and a core manufactured by a normal temperature self-hardening method using a resin manufactured by adding 0.1 to 3% by weight of an alkoxysilane represented by the formula This is a useful technique because it can be increased by 100 to 400% as compared with the case where no is used.

In Japanese Patent Publication No. 59-34456, an organic silicon compound represented by the general formula (Wherein, R ¹ and R ² each independently represent an alkyl, aryl, substituted aryl, or heteroalkyl group, and R ³ has 2 carbon atoms.
And X is an alkylene group, X is an amino group, a mercapto group,
Represents a ureido group, a glycidoxy group, or an aminoalkylamino group. By using the dialkoxysilane compound represented by the formula (1), a storage agent having better storage stability than the acid-curable molding sand binder added with the trialkoxysilane compound disclosed in JP-B-43-15161. A method for obtaining an agent composition is provided.

However, even in a cured product produced using a binder composition containing any organosilicon compound, the moisture resistance is low,
In particular, there was a problem that deterioration was severe under high humidity.

[Object of the invention]

An object of the present invention is to provide a novel organosilicon compound which solves the above drawbacks and provides a cured product having improved moisture resistance, and to provide an acid-curable molding sand binder containing the same.

[Configuration of the invention]

The present inventors have conducted intensive studies to obtain the above-mentioned acid-curable molding sand binder, and found that the addition of a specific organosilicon compound was extremely effective, and confirmed the effect thereof. The present invention has been made.

That is, the present invention provides a compound represented by the general formula (I): (However, R ¹ is an alkylene having 1 to 6 carbon atoms, R ² is a specific substituted or unsubstituted monovalent hydrocarbon group, and Y is 1 to 6 carbon atoms.
N represents an integer of 1 to 6, and m represents 0 or 1. The present invention also relates to an organosilicon compound represented by the formula (1), and an acid-curable molding sand binder which gives a cured product having improved moisture resistance, comprising the organosilicon compound and an acid-curable resin as main components.

R ¹ in the organosilicon compound represented by the general formula (I) of the present invention represents an alkyl group having 1 to 6 carbon atoms, and a methyl group is particularly preferred because of easy availability. Examples of the substituted or unsubstituted monovalent hydrocarbon group for R ² include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and a hexyl group; a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group; Aralkyl groups such as phenylethyl group; aryl groups such as phenyl group and tolyl group; and substituted hydrocarbon groups such as chloromethyl group, chlorophenyl group and 3,3,3-trifluoropropyl group. However, a methyl group is preferred from the viewpoint of availability. Examples of the alkoxy group having 1 to 6 carbon atoms of Y include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.
An alkoxy group having 1 to 3 carbon atoms, particularly a methoxy group or an ethoxy group, is more preferred from the viewpoint of reactivity and availability.

In the formula, n = 1 to 3 is preferred from the viewpoint of availability, and n = 3 is particularly preferred from the viewpoint of the stability of the product. M is 0 or 1.

The substitution position of the R ¹ group and the amino group on the phenyl group may be any position.

Examples of such organosilicon compounds include 2-amino-
4- [N- {3- (trimethoxysilyl) propyl}]
Aminotoluene, 4-amino-2- [N- {3- (trimethoxysilyl) propyl}] aminotoluene, 2-amino-6- [N- {3- (trimethoxysilyl) propyl}] aminotoluene, 3 -Amino-4- [N- {3-
(Trimethoxysilyl) propyl {] aminotoluene,
4-amino-3- [N- {3- (trimethoxysilyl)
Propyl}] aminotoluene, 2-amino-4- [N-
{3- (dimethoxymethylsilyl) propyl}] aminotoluene, 4-amino-2- [N- {3- (dimethoxymethylsilyl) propyl}] aminotoluene, 2-amino-6- [N- {3- ( Dimethoxymethylsilyl) propyl}] aminotoluene, 3-amino-4- [N- {3
-(Dimethoxymethylsilyl) propyl}] aminotoluene, 4-amino-3- [N- {3- (dimethoxymethylsilyl) propyl}] aminotoluene and the like.

These organosilicon compounds are usually a mixture of diaminoalkylbenzene and chloropropylsilane derivative,
It is synthesized by heating and stirring.

The reaction can be carried out at a temperature in the range of 0 to 180 ° C, but preferably in the range of 50 to 150 ° C. The pressure during this reaction is generally performed at normal pressure, but may be increased or reduced if necessary.

In the reaction, the use of a solvent is not particularly required, but may be used for enhancing the solubility of the raw materials or controlling the temperature. As such a solvent, a solvent having no reactivity with an amino group or an alkoxy group can be used, for example, toluene, xylene, cyclohexane,
Hydrocarbon solvents such as n-hexane, n-heptane, naphtha, mineral spirits and petroleum benzine; halogenated hydrocarbons such as chloroform, carbon tetrachloride, trichloroethylene, perchlorethylene, 1,1,1-trichloroethane Solvents; ether solvents such as ethyl ether, tetrahydrofuran and ethylene glycol diethyl ether; and aprotic polar solvents such as dimethylformamide and dimethylacetamide.

The reaction time is not particularly limited because it depends on the starting material, catalyst, solvent, reaction temperature, and the like used. However, conditions are usually set such that the reaction is completed in 0.5 to 8 hours. Since the resulting compound is obtained in the form of a hydrochloride, it is preferable to remove hydrochloric acid by treating with an excess of an amine or a metal alkoxide.

Since two amino groups are present in the raw material, the product is a mixture of isomers depending on the position of the amino group that reacts with chloropropylsilane. However, when it is added to the binder, there is no problem in the mixture as it is. If necessary,
Separation is possible by methods such as rectification, gas chromatography, and liquid chromatography.

The amount of the organosilicon compound according to the present invention is usually 0.015 to 5.0% by weight in the binder, preferably 0.05 to 2.0% by weight.
% By weight.

As the resin used in the present invention, furan resin, phenolic resin, furfuryl alcohol, urea resin each is used alone or a mixture used in a general acid-curable molding sand binder such as a mixture, effective, In particular, furan urea resin or furan phenol resin produced by adding furfuryl alcohol is preferably used. Further, those obtained by subjecting these resins to urea modification, phenol modification, and furan modification are included in the resin according to the present invention.

Usually, in order to produce a mold and a core using the present composition, it is produced by kneading refractory particles such as silica sand, zircon sand and chromite sand together with a curing agent.

Examples of the curing agent include known inorganic and organic acid-based ones (for example, an aqueous solution of sulfuric acid, phosphoric acid or the like or a non-aqueous solvent solution is typical as the inorganic acid-based agent, and benzenesulfonic acid, toluene sulfone An aqueous solution or a non-aqueous solvent solution of a sulfonic acid such as an acid is typically used, but is not particularly limited thereto.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.
In the examples, all “parts” are “parts by weight”. Further, the following examples do not limit the present invention. In the formula, Me represents a methyl group.

Example 1 122 parts of 2,4-diaminotoluene and 66 parts of γ-chloropropyltrimethoxysilane were placed in a reaction vessel equipped with a cooling tube with a drying tube, and stirred at 110 ° C. for 10 hours. Then 50
Cooled to 60 ° C., 60 parts of methanol was added, and 71 parts of sodium methylate (25% by weight methanol solution) was further added.
Stir for 30 minutes. Distillation under reduced pressure (195-200 ℃)
/0.5 Torr) to obtain 27 parts of a pale yellow transparent liquid. From the results of elemental analysis, Mass, NMR, and IR of the obtained liquid, the obtained liquid was found to be 2-amino-4- [N- {3-trimethoxysilyl) propyl}] aminotoluene and 4-amino-4- [N- {3-trimethoxysilyl) propyl}] aminotoluene
It was found to be a mixture of amino-2- [N- {3-trimethoxysilyl) propyl}] aminotoluene.

NMR (90 MHz, CCl ₄ , δ), 0.57-0.83 (m, 2H, Si-CH ₂ ) 1.43-1.93 (m, 2H, Si-C-CH ₂ ) 2.20 (s, 3H, Ph-CH ₃ ) 3.10 (t, J = 7Hz, 2H , NC H 2) 3.60 (s, 9H, O-CH 3) 4.07 (s, 3H, NH) 6.03-7.10 (m, 3H, aromatic) IR (cm -1) 3400, 3350, 3210, 3020, 2960 2850, 1630, 1620 Mass (M ⁺ ) 284 Elemental analysis C 54.65 (54.90) (Calculated values in parentheses) H 8.69 (8.51) N 9.80 (9.85) Si 9.77 (9.87) Example 2 The reaction was carried out in the same manner as in Example 1 except that γ-chloropropyltrimethoxysilane was changed to 60 parts of γ-chloropropyldimethoxymethylsilane. As a result, 190 ~ 197 ℃ / 0.5To
As a boiling point of rr, 24 parts of a pale yellow transparent liquid were obtained. This product was identified as 2-amino-4- [N-
It was found to be a mixture of {3-dimethoxymethylsilyl) propyl}] aminotoluene and 4-amino-2- [N- {3-dimethoxymethylsilyl) propyl}] aminotoluene.

NMR (90 MHz, CCl ₄ , δ), 0.07 (m, 2H, Si-CH ₃ ) 0.57-0.83 (m, 2H, Si-CH ₂ ) 1.43-1.93 (m, 2H, Si-C-CH ₂ ) 2.20 (s, 3H, Ph-CH 3) 3.10 (t, J = 7Hz, 2H, NC H 2) 3.60 (s, 6H, O-CH 3) 4.00 (s, 3H, NH) 6.03-7.10 (m, 3H , aromatic) IR (cm ^-1 ) 3400,3350,3200,2960,2850 1630,1260 Mass (M ⁺ ) 268 Elemental analysis C 57.99 (58.17) (Calculated values in parentheses) H 9.13 (9.01) N 10.38 (10.44) ) Si 10.35 (10.46) Examples 3 and 4, Comparative Examples 1 and 2 A hardener was added to 400 parts of silica sand for casting (Kobe Rikagaku Kogyo KK,
# 150B) 2 parts were added and stirred for 1 minute. Next, 4 parts of a furan resin (XFURAN # 522B, Kobe Rikagaku Kogyo Co., Ltd.) in which 0.02 parts of the organosilicon compound shown in Table 1 was dissolved was added, and the mixture was further stirred for 1 minute. It was immediately transferred to four 50 mm × 50 mmφ containers and cured at 20 ° C. and 55% RH for 24 hours. Then, take out from the container, two more under the same conditions
Leave for 24 hours, the other two in a sealed container with water,
Left for 24 hours without contact with water. Then, the coercive pressure of each specimen was measured.

Table 1 shows the test results, each of which is an average value of two test specimens.

[Effect of the Invention] The novel organosilicon compound of the present invention is not only effective as a silane coupling agent, an adhesion improver, and a glass fiber treating agent, but also an acid-curable molding sand containing the present organosilicon compound. It was confirmed that the agent improved the moisture resistance after curing as compared with the conventionally used binder.

This means that it is possible to reduce costs in making a high moisture resistant mold, and it is also possible to reduce the amount of gas generated during casting, and it is also useful for reducing casting defects caused by generated gas. is there.

Claims (2)

(57) [Claims] 1. The compound of the general formula (I) (However, R ¹ is an alkyl group having 1 to 6 carbon atoms, R ² is selected from an alkyl group, a cycloalkyl group, an aralkyl group, an aryl group, a chloromethyl group, a chlorophenyl group and a 3,3,3-trifluoropropyl group. Substituted or unsubstituted monovalent hydrocarbon group, Y is an alkoxy group having 1 to 6 carbon atoms, n is 1 to
Integer of 6, m represents 0 or 1. ) An organosilicon compound represented by the formula: 2. A binder for molding sands comprising an organosilicon compound represented by the general formula (1) according to claim 1 and an acid-curable resin as main components.