JPH09328489A - Production of silicon-containing isocyanate compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject compound containing a highly reactive NCO group and a silyl group giving good flexibility and adhseivity and useful as a modifying agent, a molecular terminal-sealing agent, etc., in a high yield by decomposing a specific Si-containing compound in the presence of an isocyanate compound and a metal catalyst. SOLUTION: A compound having a structure represented by formula I R<1> is a silicon-containing hydrocarbon having a structure expressed by a group of formula II [R<2> is a 1-8C monovalent organic group; R<3> -R<5> are each a 1-8C organic group, a siloxy group of the formula: OSiR<6> R<7> R<8> (R<6> -R<8> are each a 1-8C monovalent organic group); (m) is an integer of 1-10; (l) is an integer of 0-3], etc.; (n) is an integer of >=1; X is an organic group bound to R<1> through a urea group of the formula: NHCOHN} is decomposed in the presence of an isocyanate compound and a metal catalyst to easily obtain the objective silicon-containing isocyanate compound having a structure of the formula: R<1> -NCO, containing a highly reactive isocyanate group and a silyl group giving good flexibility and adhesivity, and useful as a modifying agent, a molecular terminal-sealing agent, etc., in a high purity and in a high yield.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an isocyanate compound containing a highly reactive isocyanate group and a silyl group which imparts flexibility and adhesiveness, and which is useful as a modifying agent, a terminal blocking agent, and the like. .

[0002]

2. Description of the Related Art A silyl group-containing isocyanate compound produced by the present invention contains an isocyanate group having high reactivity with active hydrogen and a silyl group exhibiting flexibility and adhesion to an inorganic substrate in one molecule. Since it is contained, it is very useful as a modifier and an end-capping agent.

As a method for producing a compound containing an isocyanate group and a silyl group at the same time, a method is known in which phosgene and a dehydrochlorinating agent are used in combination, as disclosed in JP-A-6-228161. According to this method, harmful phosgene must be used, and a large amount of a salt of the compound used as the dehydrochlorination agent is generated, so that the treatment requires a great deal of cost and is not economical. In addition, since it has a drawback that hydrochloric acid that reduces the reactivity of the isocyanate group remains in the system, it is not a satisfactory method in terms of product purity.

As a method other than this, for example, a method of vaporizing carbamatoorganosilane and thermally decomposing it in a gas phase has been disclosed (JP-A-7-258273).
In general, the vapor phase method reacts at a very high temperature, and the endothermic reaction heat is large, so that it is difficult to design a reactor, and thus it is not practical.
Furthermore, since a considerable amount of heat is applied during the vaporization of carbamatoorganosilanes, the compound itself may be decomposed, which is not a satisfactory method either.

[0005]

As described above, various methods have been proposed as a method for producing a silyl group-containing isocyanate compound, but a method using phosgene, which is highly toxic, and an economically disadvantageous gas phase. In any case, it was not obtained with high purity and high yield, and it was not economical.

Therefore, an object of the present invention is to provide a method for easily producing an isocyanate compound containing a silyl group with high purity and high yield.

[0007]

As a result of intensive studies, the present inventors have found that a method of thermally decomposing a specific urea compound in the coexistence of an isocyanate compound and a metal compound is useful, and arrived at the present invention. .

That is, the present invention provides a compound (I) having a structure of (R ¹ ) _n --X (wherein R ¹ is a hydrocarbon group containing silicon, n is an integer of 1 or more, and X is R ¹ ). -NHCO
HN-, which represents an organic group characterized by binding via a urea group), is decomposed in the presence of an isocyanate compound and a metal catalyst to produce a silicon-containing isocyanate compound having a structure of R ¹ -NCO. And a method for producing an isocyanate.

R ¹ in the general formula (I) used in the present invention is not particularly limited as long as it is a silicon-containing hydrocarbon group, and the hydrocarbon is an aliphatic group, an alicyclic group or an aromatic group. May be However, the reaction target product, R ¹ -NCO
In consideration of separating the silicon group-containing isocyanate compound having the following structure from the system by distillation or the like, R
The total number of carbon atoms and silicon atoms contained in ¹ is preferably 40 or less, more preferably 30 or less.

X in the general formula (I) is an organic group characterized by being bonded to R ¹ through a urea group represented by NHCOHN. Here, X is not particularly limited as long as it is an organic group which can be bonded to R ¹ via a urea group at least at one position.

However, when the concentration of the urea group in X is too low, the production efficiency becomes low, which is not preferable.
Therefore, the concentration of the urea group bound to R ¹ in X is 10 w
It is realistic that it is t% or more, and 20 wt% or more is preferable.

In the general formula (I), n is an integer of 1 or more. That is, X may be bound to a plurality of R ¹ via a urea group, and even if X contains a free isocyanate or a urea group not bound to R ¹ , no problem occurs. Absent.

As will be described later, this is because the compound represented by the general formula (1) is obtained, for example, by reacting an amine compound R ¹ -NH ₂ with an isocyanate compound, and therefore is used for the above X. When there are a plurality of urea groups bonded to R ¹ depending on the type of isocyanate used,
This may occur when free isocyanate is contained or when X has a urea group, but these do not hinder the production of R ¹ -NCO by the thermal decomposition reaction.

The isocyanate compound used in the present invention is not particularly limited as long as it is a compound containing an isocyanate group. For example, an aromatic polyisocyanate compound, an alicyclic aliphatic polyisocyanate compound containing araliphatic, and a mixture of these polyisocyanate compounds and monoisocyanate compounds can be used. However, in consideration of separation from the target product R ¹ -NCO, a compound having a sufficient boiling point difference from R ¹ -NCO is preferable. Specific examples of the polyisocyanate compound include, for example, TDI (tolylene diisocyanate), MDI (diphenylmethane diisocyanate), PDI (phenylene diisocyanate), H6X.
DI (hydrogenated xylylene diisocyanate), IPDI
(Isophorone diisocyanate), CHDI (cyclohexane diisocyanate), H12MDI (hydrogenated diphenylmethane diisocyanate), XDI (xylylene diisocyanate), TMXDI (tetramethylxylylene diisocyanate), HDI (hexamethylene diisocyanate) and the like. Polymers such as allophanates, burettes and trimer bodies of these polyisocyanates are also preferable. Examples of monoisocyanates include PMI (phenyl monoisocyanate) and CHMI (cyclohexane monoisocyanate).
And the like. Further, considering economy, easiness of handling, and recovery after the reaction, a monomer of TDI (tolylene diisocyanate) or MDI (diphenylmethane diisocyanate), a polymer thereof, or the like is particularly preferable, and is used alone. Alternatively, they can be mixed and used.

As the above R ¹ , those represented by the following general formula (II) are preferable.

[0016]

Embedded image

R ² in the general formula (II) is an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group or an octyl group, a cycloalkyl group such as a cyclopentyl group or a cyclohexyl group, a phenyl group or a tolyl group. Aralkyl groups such as aryl groups and benzyl groups, alkenyl groups such as vinyl groups and allyl groups, alkoxy groups such as methoxy groups and ethoxy groups, or some or all of the hydrogen atoms bonded to these carbon atoms are halogen atoms. An unsubstituted or substituted monovalent organic group having 1 to 8 carbon atoms selected from a chloromethyl group substituted with a cyano group, a 3,3,3-trifluoropropyl group, a 2-cyanoethyl group, R ³ ,
R ^4, R ⁵ is or a monovalent organic group having 1 to 8 the same carbon number as R ^2, indicated by ^{-OSiR 6, R 7, R 8} , R 6, R 7, R 8 are the same number of carbon atoms as R ² A siloxy group which is a monovalent organic group of 1 to 8, for example, a trimethylsiloxy group, a chloromethyldimethylsiloxy group, a 3,3,3-trifluoropropyldimethylsiloxy group, and the like, m is an integer of 1 to 10, and l is It is 0 to 3.

Therefore, as the isocyanate compound to be produced, for example, 3-isocyanatopropyltris (trimethylsiloxy) silane, 3-isocyanatopropylmethylbis (trimethylsiloxy) silane, 3
-Isocyanatopropyldimethyl (trimethylsiloxy) silane, 3-isocyanatopropyltris (pentamethyldisiloxanyl) silane, 3-isocyanatopropylmethylbis (pentamethyldisiloxanyl) silane, 3-isocyanatopropyldimethyl (Pentamethyldisiloxanyl) silane, 3-isocyanatopropyltris (heptamethyltrisiloxanyl) silane,
3-isocyanatopropylmethylbis (heptamethyltrisiloxanyl) silane, 3-isocyanatopropyldimethyl (heptamethyltrisiloxanyl) silane,
3-isocyanatopropyltris (nonamethyltetrasiloxanyl) silane, 3-isocyanatopropylmethylbis (nonamethyltetrasiloxanyl) silane, 3
-Isocyanatopropyldimethyl, (nonamethyltetrasiloxanyl) silane, 6-isocyanatohexyltris (trimethylsiloxy) silane, 6-isocyanatohexylmethylbis (trimethylsiloxy) silane, 6-isocyanatohexyldimethyl (trimethylsiloxy) ) Silane, 10-isocyanatodecyltris (trimethylsiloxy) silane, 10-isocyanatodecylmethylbis (trimethylsiloxy) silane, 10
-Isocyanatodecyldimethyl (trimethylsiloxy) silane, 1-isocyanatomethyltrimethylsilane, 1-isocyanatomethyltriethylsilane, 1-
Isocyanatomethyltrimethoxysilane, 1-isocyanatomethyldimethoxymethylsilane, 1-isocyanatomethylmethoxydimethylsilane, 1-isocyanatomethyltriethoxysilane, 1-isocyanatomethyldiethoxyethylsilane, 3-isocyanatopropyltrimethyl Silane, 3-isocyanatopropyltriethylsilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyldimethoxymethylsilane, 3-isocyanatopropylmethoxydimethylsilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanate Propyldiethoxyethylsilane, 3-isocyanatopropylethoxydiethylsilane, 6-isocyanatohexyltrimethoxysilane, 6-isocyanate Over preparative hexyl dimethoxy methyl silane, 6-isocyanate-hexyl methoxy dimethylsilane, 6-isocyanato-hexyl triethoxysilane,
6-isocyanatohexyldiethoxyethylsilane,
6-isocyanatohexyl ethoxydiethylsilane etc. are illustrated.

In the present invention, there is no particular limitation on the method and conditions for synthesizing the compound (I). Compound (I)
Can also be easily produced, for example, by reacting an amine compound represented by R ¹ —NH ₂ and an isocyanate compound at room temperature without a catalyst. In this case, the decomposition reaction can be carried out subsequently in this system without isolation, and such a method is practical and preferable.
Further, the isocyanate compound coexisting in the system may be added at the stage of decomposing the compound represented by the above general formula, or the isocyanate compound may be added at the stage of the reaction between the amine compound represented by R ¹ —NH ₂ and the isocyanate compound. It is also possible to charge the compound in excess with respect to the amine compound and use it as it is for the decomposition reaction.

The metal catalyst used in the present invention is Sn, S, which is used for urethane reaction of isocyanate and hydroxyl group.
b, Fe, Co, Ni, Cu, Cr, Ti, Pb, etc., one or more metal simple substance, or an oxide thereof,
Metal compounds such as halides, carboxylates, phosphates, and organometallic compounds can be used, but in the present invention, Fe, Sn, Co, and Sb are particularly useful because they hardly generate by-products. is there.

Further, compounds of Fe and Sn are more preferable because the reaction proceeds rapidly and the target compound can be obtained in a short time.

Examples of the Sn compound include tin oxide,
Tin chloride, tin bromide, tin iodide, tin formate, tin acetate, tin oxalate, tin stearate, tin oleate, tin phosphate, dibutyltin dichloride, dibutyltin dilaurate, 1,1,3,3-tetrabutyl -1,3-
Dilauryloxy distannoxane etc. are mentioned.

Examples of Fe compounds include iron acetate, iron benzoate, iron naphthenate, and iron acetyl acetate.

Examples of Co compounds include cobalt acetate, cobalt benzoate, cobalt naphthenate, and cobalt acetylacetonate.

The Sb compounds include trioxide, tetraoxide, antimony pentaoxide, trichloride and antimony pentachloride, antimony oxychloride, antimony tribromide, antimony triiodide, antimony sulfate, triphenylantimony, trisulfide, And antimony pentasulfide, pentaphenyl antimony, triphenyl antimony dichloride and the like.

The amount of the catalyst used is 0.0001 to 5% by weight, preferably 0.01 to 1% by weight, based on the reaction solution as a metal simple substance or a metal catalyst.

The amount of the isocyanate compound used in the present invention is preferably in the range of 1.0 to 10 mol of isocyanate group to 1 mol of urea group to be thermally decomposed. When the amount of the isocyanate group used is less than 1.0 with respect to 1 mol of the urea group, it is difficult to increase the yield sufficiently, and when it exceeds 10, it is not economical.

In the present invention, the reaction can be carried out in the presence of a suitable solvent which is inert to this system. Specifically, aromatic hydrocarbons commonly used as a heat medium such as dibenzyltoluene, triphenylmethane, phenylnaphthalene, biphenyl, diethylbiphenyl, and triethylbiphenyl are preferable. The amount of these inert solvents used is
It is in the range of 0 to 100 parts by weight, preferably 0, relative to 1 part by weight of the urea compound represented by the above general formula as a raw material.
To 50 parts by weight, more preferably 0 to 20 parts by weight.
Further, depending on the reaction conditions, it is also possible to carry out under solventless conditions.

The reaction temperature of the present invention is such that the urea compound of the above general formula decomposes. Specifically, it is 350 ° C. or lower, preferably 80 to 350 ° C., more preferably 80 to 300 ° C. Although the reaction temperature can be set higher than this range, by-products are likely to occur, and at lower temperatures, the decomposition reaction is very slow, which is not economical.

The present invention comprises a urea compound, a solvent, a metal catalyst,
Batch reaction in which isocyanate compounds are charged all at once,
Either a continuous reaction in which a urea compound or an isocyanate compound is charged under reduced pressure in a solvent containing a metal catalyst and an isocyanate compound can be carried out.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION

Example 1 MD in a 500 ml 3-neck flask equipped with a capillary, thermometer, fractionator, dropping funnel, fractionator and condenser.
After charging 125 g (0.5 mol) of I,
-221 g of aminopropyltriethoxysilane (1 mo
l) was added dropwise over 30 minutes. After the dropping was completed, the temperature inside the flask was raised to 80 ° C. to sufficiently react the amino group and the isocyanate group. At this time, as a result of IR measurement, the peak of the isocyanate group was completely disappeared. MDI in the flask
After charging 125 g and dibutyltin dilaurate 0.075 g, the temperature inside the flask was raised to 225 ° C.
The pressure was reduced to 0 mmHg. When the tower temperature reached about 120 ° C., distillation of the liquid compound started, and finally 200 g of a reaction product was obtained. Composition analysis of the product revealed that it contained γ-isocyanatopropyltriethoxysilane with a purity (GC) of 99% (yield 86.1).
%).

Example 2 MDI added in Example 1 after synthesis of the urea compound
Was carried out in the same manner as in Example 1 except that the amount of the above was 250 g and the catalyst to be added at the same time was cobalt naphthenate. As a result, γ-isocyanatopropyltriethoxysilane was obtained with a GC purity of 99.2% and a yield of 88.7%.

Example 3 MDI125 added after synthesis of urea compound in Example 1
Reaction was carried out in the same manner as in Example 1 except that g was 94 g of XDI (xylylene diisocyanate). As a result, γ
-Isocyanatopropyltriethoxysilane was obtained with a GC purity of 98.9% and a yield of 84.9%.

Example 4 A reaction was conducted in the same manner as in Example 1 except that γ-aminopropyltrimethoxysilane was used as the dropping amine compound in Example 1, and γ-isocyanatopropyltrimethoxysilane had a GC purity of 99. .3%, yield 82.8%
Got with.

Comparative Example 1 After the synthesis of the urea compound in Example 1, the reaction was carried out in the same manner as in Example 1 except that MDI was not added.
The yield of γ-isocyanatopropyltriethoxysilane was 5.4%, and the GC purity was 92%.

[0036]

EFFECTS OF THE INVENTION According to the method of the present invention, a silyl group-containing isocyanate compound, which is very useful as a modifier and an end-capping agent, can be produced in high yield and high purity with high selectivity, and harmful phosgene and the like can be eliminated. It is industrially very useful in that it is not used.

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Claims (6)

[Claims] 1. A compound (I) having a structure of (R ¹ ) _n —X (wherein R ¹ is a hydrocarbon group containing silicon, n is an integer of 1 or more, and X is R ¹ and —NHCOHN—. An organic group characterized by being bonded via a urea group shown) is produced in the presence of an isocyanate compound and a metal catalyst to produce a silicon-containing isocyanate compound having a structure of R ¹ -NCO. A method for producing a characteristic isocyanate. 2. The method for producing an isocyanate compound according to claim 1, wherein R ¹ has a structure represented by the general formula (II). Embedded image (Here, R ² is a monovalent organic group having 1 to 8 carbon atoms, R ³ , R ⁴ ,
R ⁵ is a monovalent organic group having 1 to 8 carbon atoms or —OSiR ⁶ R ⁷
A siloxy group represented by R ⁸ (R ⁶ R ⁷ R ⁸ is a monovalent organic group having 1 to ⁸ carbon atoms) m is an integer of 1 to 10, and l is an integer of 0 to 3) 3. The method for producing an alkoxy group-containing isocyanate according to claim ¹ , wherein R ¹ contains at least one alkoxysilyl group. 4. The molar ratio of the NCO group in the isocyanate compound to the urea group in the compound (I) is 1: 1.0 to.
The range of 10 is the manufacturing method of the isocyanate of Claims 1-3 characterized by the above-mentioned. 5. The metal catalyst comprises one or more of Fe, Sn and Co.
5. The method for producing an isocyanate according to claim 1, wherein the metal simple substance of Sb and Sb or the metal compound is Sb. 6. The method for producing an isocyanate according to claim 1, wherein the isocyanate compound is a monomer of TDI (tolylene diisocyanate) or MDI (diphenylmethane diisocyanate), or a polymer thereof.