JPH03239774A - Coating material composition - Google Patents

Abstract

PURPOSE:To obtain a coating material composition capable of undergoing polycondensation to form a coating film having uniform strength without using a catalyst such as an acid or a base by incorporating a tetraalkoxytitanium into a silicon component consisting mainly of methylpolysiloxane. CONSTITUTION:A silicon component consisting mainly of a methylpolysiloxane of formula I (wherein n is 0 to 4), obtained by the hydrolysis and polycondensation of tetramethoxysilane in the presence of water, methanol, and an acid catalyst, is mixed with a tetraalkoxytitanium of formula II (wherein R is 1-5C alkyl) so as to provide a ratio of SiO2 to TiO2 of (3 to 10):1, giving a coating material composition.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention provides an inorganic film with excellent heat resistance and durability on the surface of metal, glass, plastic, etc., or on the surface of a coating film applied to these surfaces. formation, high temperature oxidation prevention,
The present invention relates to a coating composition used for purposes such as corrosion resistance, heat insulation, and antifouling properties.

[Conventional technology]

Conventionally, this type of coating agent composition is known to use a metal alcoholade, especially a tetraalkoxysilane (silicate ester, 5i (OR), ), and this tetraalkoxysilane has a higher It is not only inexpensive but also has excellent chemical stability, and is used for many purposes.

When tetraalkoxysilane is used as a coating agent composition, the hydrolysis rate of this tetraalkoxysilane is slow and it takes a long time to polycondense and form a strong network structure on the surface of the material to be coated. Generally, acid catalysts or base catalysts are used.

However, when an acid catalyst or a base catalyst is used in such a coating agent composition, the coating agent composition itself becomes acidic or basic, and depending on the type of material to be coated, such as metal, glass, plastic, or paint film, these properties may vary. In addition to the necessity of using either acidic or basic coating agent compositions, depending on the type of material to be coated, the acid catalyst or base catalyst in the coating agent composition may inevitably cause adverse effects such as corrosion.

In addition, as a method that does not use such an acid catalyst or a base catalyst, the above-mentioned tetraalkoxysilane and tetraalkoxyzirconium (zirconate ester, Zr(OR
) and 4) have also been proposed (Japanese Unexamined Patent Application Publication No. 1983-1999)
-106.968). However, this 5i(OR
)<-Zr(OR)- A mixed coating composition has a problem in that sufficient coating film strength cannot necessarily be obtained.

That is, in the above-mentioned 5t(OR)*-Zr(OR)+ mixed coating composition, as described in, for example, the Ceramic Industry Association Journal, Vol. 85, pp. 448-454 (1977), tetraalkoxyzirconium When polycondensed with tetraalkoxysilane, it does not form a Si-0-M type network structure (where M is a metal atom), but instead enters the space of the silica network structure, which makes it difficult to coat. From the point of view of film strength, it does not necessarily exhibit a sufficient effect. Moreover, this hydrolysis rate,
Furthermore, from the viewpoint of polycondensation rate, tetraalkoxyzirconium is significantly faster than tetraalkoxysilane, and in a coating film formed from a coating composition of 5t(OR)*-Zr(OR) < mixed system, Tetraalkoxyzirconium, which has a high hydrolysis rate, is polycondensed first, and then tetraalkoxysilane is polycondensed, resulting in an uneven coating film in some cases.

[Problem to be solved by the invention]

Therefore, as a result of intensive research to solve the various problems that conventional coating compositions have, the present inventors discovered that tetramethoxysilane, which has a relatively slow hydrolysis rate, is pre-heavy to a predetermined degree. We discovered that by using condensed methyl polysilicate and tetraalkoxytitanium, which has a relatively fast hydrolysis rate, in combination, the polycondensation rate for coating film formation was fast and the various problems mentioned above could be solved. The invention has been achieved.

Therefore, an object of the present invention is to form a coating film with a fast polycondensation rate, uniformity, and excellent coating strength without using acid catalysts or base catalysts that may have an adverse effect on the material to be coated. An object of the present invention is to provide a coating agent composition that can easily form a coating film.

[Means to solve the problem]

That is, the present invention relates to the following general formula (I) (wherein n
is an integer from 0 to 4) and the following general formula (II) OR RO-Ti-OR OR(n) (wherein R is an integer of 1 to 4 carbon atoms) This is a coating agent composition containing as a main component a titanium component consisting of tetraalkoxytitanium represented by the alkyl group of 5).

The silicon component used in the present invention is mainly composed of methylpolysilicate represented by the above general formula (I), that is, a dimer to hexamer component of tetraalkoxysilane where n=o to 4, and is preferably contains this methyl polysilicate in a proportion of 70% by weight or more, more preferably 80% by weight or more. In such methyl polysilicate, tetraalkoxysilane has undergone some degree of polycondensation in advance as a 2- to 6-molecule polycondensate, which saves time spent on polycondensation and creates a form that makes it easier to create a network structure in a shorter time. This is thought to approach the fast polycondensation rate of tetraalkoxytitanium, or
It is thought that the 5i-0-Ti bonds form a uniform and strong network structure. Therefore, if the degree of polycondensation is less than this, the polycondensation reaction takes time and it becomes difficult to form a uniform coating film with good performance. On the other hand, if the degree of polycondensation is greater than this,
The proportion of methoxy groups that form the network structure decreases, making it difficult to form a strong network structure.

The methyl polysilicate represented by the general formula (I) can be produced, for example, by polycondensing tetramethoxysilane with a predetermined amount of water in the presence of an acid or alkali catalyst, but preferably is preferably produced by polycondensing tetramethoxysilane in the presence of water, methanol and an acid catalyst. In this reaction, usually 0.4 to 0.9 mol of water is added to 1 mol of tetramethoxysilane, preferably 0.5 to 0.5 mol. 8 mol, more preferably 0°6
methanol in the range of 30 to 50 g, preferably 35 to 45 g, and an acid catalyst in the range of 1N-1 (for CI, 0.1 to 1.0-1, preferably 0
．． The reaction temperature is from 20°C to 64°C, which is the boiling point of methanol, preferably 30 to 50°C, under stirring until the reaction is completed, usually for 0.5 to 10 hours. The produced methyl polysilicate is recovered by removing unreacted tetramethoxysilane and methanol from the reaction mixture by means such as distillation after the reaction is completed.

The methyl polysilicate produced in this way is usually a 2- to 6-molecule polycondensate containing a small amount of unreacted monomer and a small amount of a polycondensate of 7 or more molecules [in general formula (I), n=
o~4]. Examples of acid catalysts that can be used in this reaction include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, and hydrofluoric acid; organic acids such as formic acid, acetic acid, propionic acid, and p-toluenesulfonic acid; Examples include solid acids such as type molecular sieves, acidic ion exchange resins, and the like.

Further, the general formula (II
), the substituent R is usually an alkyl group having 1 to 5 carbon atoms, specifically tetramethoxytitanium, tetraethoxytitanium, tetran
-Propoxytitanium, tetraisopropoxytitanium, tetra n-butyroxytitanium, tetraisobutyroxytitanium, tetra t-butyloxytitanium, tetra n-pentyloxytitanium, tetraisopentyloxytitanium, tetra 5
Examples include ec-pentyloxytitanium, and among these, the most preferred is tetraisopropoxytitanium into which an isopropyl group having 3 carbon atoms is introduced.

These tetraalkoxytitaniums undergo hydrolysis and polycondensation in the presence of water, and easily form a network structure having 5i-0-Ti bonds with tetraalkoxysilane.

Further, in the present invention, an organic solvent is used to adjust the viscosity of the coating composition to be prepared or to adjust the hydrolysis rate (polycondensation rate) of methyl polysilicate or tetraalkoxy titanium. This organic solvent may be any solvent as long as it can dissolve the main components, methylpolysilicate and tetraalkoxytitanium, and is volatile at room temperature, but preferably methanol, ethanol, isopropanol, n −
Alcohols such as butanol and isobutanol.

In addition, in the present invention, as part of the silicon component, ethyl polysilicate mainly composed of dimer to pentamer of tetraalkoxysilane or tetraethoxysilane having an alkyl group having 2 to 5 carbon atoms is used, and silicon It is also possible to adjust the rate of polycondensation of the components. The amount of these used is not particularly limited, but is usually within the range of 1 to 60 mol%. By using an appropriate amount of such tetraalkoxysilane or ethyl polysilicate as part of the silicone component and adjusting the polycondensation rate of the silicone component, a coating composition with even more uniformity and superior coating film strength can be created. can prepare things.

Furthermore, the blending ratio of the silicon component and titanium component is preferably in the range of 3 to 1O1, preferably 4 to 8 in terms of the ratio of 5i02/TiOx, and this Siem/Ti1t
When the ratio is smaller than 3, there is a problem that a non-uniform coating film is likely to be formed, and on the other hand, when the ratio is larger than 10, there is a problem that the coating film strength is reduced.

In addition, in the present invention, in addition to the above-mentioned components, this type of coating composition is used to impart properties such as heat resistance, infrared radiation, conductivity, and electrical resistance, or to provide a desired color. Various conventionally known additives can also be added.

[Made, for]

The coating agent composition of the present invention has a fast polycondensation rate due to its hydrolysis, and there is no need to add water necessary for this hydrolysis in advance, and when it is applied to the surface of the material to be coated, it can be quickly removed from the atmosphere. Alternatively, it is hydrolyzed by moisture adhering to the material to be coated, and a coating film is formed by the simultaneous polycondensation reaction. At this time, in the coating composition of the present invention, in addition to the silicone component, general formula (II)
In addition to containing tetraalkoxytitanium represented by as a titanium component, a silicon component exists in the form of methyl polysilicate represented by the above general formula (I), so polycondensation by hydrolysis of these silicon components and titanium components is possible. It is believed that the velocities are close or coincident, thereby forming a uniform and strong network structure having 5i-0-Ti bonds. Furthermore, since the coating composition of the present invention has this bonding structure, the coating film thereof has excellent alkali resistance.

〔Example〕

The present invention will be specifically described below based on Examples and Comparative Examples.

[Preparation of methyl polysilicate) (MPS-A, MPS-B)]

In a reactor equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, 152 g (1 mol) of tetramethoxysilane (TMS) and 12.0 g of water were added. 6 g (0.7 mol) and 50 g of methanol were charged, and the contents were heated to 30° C. with stirring. Then, 0.6 g (0.7 mol) of IN nitric acid or IN hydrochloric acid was added as an acid catalyst.
5- was added and allowed to react for 3 hours under stirring. During this time, the temperature of the reaction mixture was increased to 48° C. in about 10 minutes.

Thereafter, the mixture was allowed to stand for an additional 18 hours, and then the temperature was raised to 160'C to distill off low-boiling components to obtain a distillate and a residue from the pot.

When IN nitric acid is used as an acid catalyst (MPS-A)
, the yield of distillate was 91.5g and the yield of pot residue was 113g.
(95% yield as SiO□), and when IN hydrochloric acid was used as the acid catalyst (MPS-8), the yield of distillate was 91.0 g and the yield of pot residue was 114 g (
The yield was 95% as SjOz). The composition of the obtained pot residue was investigated by gas chromatographic analysis, and the silica content, 25°C specific gravity, and 25°C viscosity were also investigated.

The results are shown in Table 1.

Table 1 Example 1 Methyl polysilicate (MPS-A) prepared above in a 200 ml beaker 36. 5 g (0.30 mol) and tetraisopropoxytitanium 15. 3 g (0,
05 mol) and added n-butanol to make a total of 100 g, then covered with a strong polyethylene sheet and stirred at 25°C using a magnetic stirrer.
The mixture was reacted for 2 hours with stirring.

After the reaction was completed, the obtained reaction product was applied by the dip method onto a piece of iron with a length and width of 2 cm, the surface of which had been polished cleanly, and left in the air for 10 minutes to dry. It was further heated at 150° C. for 10 minutes to form a coating film on the iron piece.

For the obtained paint film, sellotape was pasted on the surface, and when it was peeled off, the strength of the paint film was examined by determining how much of the paint film was destroyed and detached.The results were ◎: Completely remained. , O: Almost all remained and only a portion of it was removed, △D Part of it was removed, ×: Most of it was removed, X
×: Evaluation was made based on the criteria of complete detachment. The results are shown in Table 2.

Example 2 As silicon components, 18.2 g (0.15 mol) of the methyl polysilicate (MPS-8) prepared above and ethyl polysilicate (mainly composed of tetra-pentamers) were used.
SiO* content rate 40X)23. A coating agent composition was prepared in the same manner as in Example 1 above, except that 2 g (0.15 mol) was used, a coating film was formed on an iron piece, and the strength of the coating film was examined. The results are shown in Table 2.

Comparative Example 1 47゜1 g of tetramethoxysilane as silicon component
A coating agent composition was prepared in the same manner as in Example I above, except that (0.30 mol) was used, a coating film was formed on an iron piece, and the strength of the coating film was examined.

The results are shown in Table 2.

Comparative Example 2 Tetra-n-butoxyzirconium was used instead of tetraisopropoxytitanium 19. A coating agent composition was prepared in the same manner as in Example 1 above, except that 2 g < 0.05 mol) was used, a coating film was formed on an iron piece, and the strength of the coating film was examined. The results are shown in Table 2.

2. Without mentioning, it is possible to easily form a coating film having a fast polycondensation rate, uniformity, and excellent coating strength, and has extremely great industrial significance.

Claims (4)

[Claims] (1) Silicon component mainly composed of methyl polysilicate represented by the following general formula (I) ▲Mathematical formula, chemical formula, table, etc.▼(I) (However, in the formula, n is an integer from 0 to 4) and the following general formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (However, in the formula, R represents an alkyl group having 1 to 5 carbon atoms) A titanium component consisting of tetraalkoxytitanium and A coating agent composition characterized by having as a main component. (2) The following general formula (I) obtained by polycondensing tetramethoxysilane in the presence of water, methanol, and an acid catalyst. A silicon component mainly composed of methyl polysilicate represented by (an integer from 0 to 4) and the following general formula (II) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (II) (However, in the formula, R is the number of carbon atoms A coating agent composition containing as a main component a titanium component consisting of tetraalkoxytitanium represented by 1 to 5 alkyl groups. (3) The coating agent composition according to claim 1 or 2, wherein the silicone component contains methyl polysilicate represented by general formula (I) in a proportion of 70% by weight or more. (4) The blending ratio of silicon component and titanium component is
The coating composition according to claim 1 or 2, wherein the O_2/TiO_2 ratio is in the range of 3 to 10.