JPH10218995A - Organopolysiloxane resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silanolated organopolysiloxane resin compsn. which does not undergo condensation even at room temp., is excellent in storage stability, and hardly exhibits the change in quality with time. SOLUTION: This compsn. contains 100 pts.wt. siloxane resin represented by the average compsn. formula: R<1> n Si(OR<2> )p (OH)q O(4-n-p-q)/2 and 40-2,000 pts.wt. at least one org. solvent selected from among org. solvents having permittivities (at 10-35 deg.C) of 4-16 (pref. tert. butanol, tert. amyl alcohol, methyl isobutyl ketone, or tetrahydrofuran). In the formula, R<1> is H or a 1-8C org. group; R<2> is 1-6C alkyl; and 0<=n<=1.8, 0<=p<=1.0, and 2<=q<=3 provided 0.8<=(n+p+q)<4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organopolysiloxane resin composition containing a silanol group (@ Si-OH) useful as a coating agent, and more particularly to an organic solvent containing an organic solvent capable of stabilizing the silanol group. To an organopolysiloxane resin composition.

[0002]

2. Description of the Related Art When an organopolysiloxane resin is used in, for example, a thermosetting paint vehicle having excellent heat resistance and weather resistance, it generally has two hydrolyzable substituents (for example, silanol groups). It is synthesized by hydrolyzing and optionally further condensing a silane monomer having up to 4 silane monomers.Since the silanol group is unstable,
It is easily condensed with the passage of time and has poor storage stability. Therefore, in an organopolysiloxane resin composition supplied as a commercial product, the silanol group content is set to 1 to 5% by weight, or 4 to 20% by mole ( Control within silicon atoms).

[0003] On the other hand, some siloxane resins containing silanol groups are used as coating agents for improving the hardness and abrasion resistance of plastic molded articles such as acrylic resins and polycarbonate resins. Some of them form a film called a hard coat having hardness. This alkoxysilane R ¹ _n Si (OR ²⁾ of the r containing directly bonded alkoxy groups to silicon atoms is hydrolyzable substituent _r (r is an essential 3 and / or 4, 1,2 May be used in combination, and the average is greater than 2 and 4 or less, and n + r is 4.)
Is a resin obtained by hydrolyzing the alkoxysilane under mild conditions using at least r molar equivalents of water.

In this case, since a silanol group is abundantly contained by hydrolysis, a resin composition in which the obtained silanol group-containing siloxane is mixed with inorganic oxide particles represented by colloidal silica is used. The surface of the SiO ₂ fine particles in the silica sol and the silanol groups contained in the siloxane resin are dehydrated and condensed by heat treatment in the presence of a catalyst to form a stable siloxane bond (—Si
—O—Si—). Therefore, the higher the silanol group content in the siloxane resin, the higher the crosslink density in the cured product, resulting in a higher hardness.

However, the silanol groups are inherently unstable, and the condensation progresses gradually with the lapse of time even at room temperature, so that the silanol groups in the resin composition before use are reduced. The hardness, abrasion resistance and the like of the obtained coating are reduced. As described above, the silanol group-containing siloxane resin has excellent performance, but has a serious drawback of poor storage stability.

It is known that silanol groups are most stable in the pH range of 3-5. Therefore, by adjusting the pH to 3 to 5, the condensation of silanol groups can be considerably suppressed, and thus the storage stability can be improved. However, there is a drawback that the storage stability is still insufficient because the temperature may increase during transportation.

On the other hand, the organopolysiloxane resin coating agent generally comprises (1) a hydrolysis / partial condensate of alkoxysilane, (2) an organic solvent and / or water, (3) a curing catalyst, and (4) an optional It is composed of metal oxide fine particles used. As the above organic solvent,
Toluene (relative dielectric constant 2.38, 25 ° C.), xylene (relative dielectric constant 2.40 (average value of ortho, meta, and para-forms), 20 ° C.) that easily dissolves organopolysiloxane resin
Aromatic solvent such as methanol (dielectric constant 32.
6, 25 ° C.), ethanol (dielectric constant 24.3, 25)
C)).

However, since the silanol groups contained in the organopolysiloxane resin in these coating agents are extremely unstable, a significant improvement is required. Particularly, a system containing water has a problem that not only the storage stability but also the adhesion to a plastic substrate and the film-forming property are poor. In order to solve these problems, a method has been proposed in which an excess amount of water is azeotropically distilled off with alcohol as a solvent to suppress the water content to 15% by weight or less (Japanese Patent Publication No. 5-428). However, although the storage stability and workability of the coating agent are improved by the method, the storage stability is still insufficient, and water must be distilled off under reduced pressure, which complicates the production process. There was also a disadvantage of becoming.

[0009]

The inventors of the present invention have conducted intensive studies to solve the above-mentioned drawbacks. As a result, the condensation reaction of the silanol group was caused by the nucleophilic conversion of the oxygen atom in the silanol group to the silicon atom. By using a polar solvent with a relatively low polarization having a certain range of dielectric constants, that it undergoes an attack and that the transition state of the reaction becomes more stable in a solvent having a high polarity, The inventors have found that the activation energy can be kept large and the stability can be improved by delaying the condensation of silanol groups, and the present invention has been achieved. Accordingly, an object of the present invention is to provide a silanol group-containing organopolysiloxane resin composition which does not condense at room temperature, has extremely excellent storage stability, and is hardly deteriorated with time.

[0010]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
a) Average composition formula R ¹ _n Si (OR ² ) _p (OH) _q O
100 parts by weight of a siloxane resin represented by _{(4-npq) / 2} (hereinafter abbreviated as Formula 1), and b) an organic solvent having a relative dielectric constant of 4 to 16 in a temperature range of 10 to 35 ° C. Achieved by an organopolysiloxane resin composition containing 40 to 2,000 parts by weight of at least one organic solvent selected. However, in the above average composition formula, R ¹ is a hydrogen atom or an organic group having 1 to 18 carbon atoms, R ² is an alkyl group having 1 to 6 carbon atoms, n, p, and q are each 0 ≦ n ≦ 1.8, 0 ≦ p ≦ 1, 0.2 ≦ q ≦ 3, and
It is a number that satisfies 0.8 ≦ n + p + q <4.

[0011] The organopolysiloxane resin represented by the above formula 1, which is an essential component in the composition of the present invention, comprises R ¹ _n
At least one represented by Si (OR ² ) _r (hereinafter abbreviated to formula 2)
It is preferably a siloxane resin consisting of a hydrolyzed condensate of a kind of alkoxysilane. The alkoxy R ¹ of the silane is the same as R ¹ in the formula 1, is a hydrogen atom or an organic group having 1 to 18 carbon atoms, specifically, methyl group,
In the skeleton of an alkyl group such as an ethyl group, a propyl group, a butyl group, a hexyl group, and a decyl group, an alkenyl group such as a vinyl group and an allyl group, a cycloalkyl group such as a cyclohexyl group, an aryl group such as a phenyl group, and an alkyl group. Having a group such as ether, ester, and carbonyl, as a substituent, a halogen atom, an epoxy group, an amino group, an acryloxy group, a methacryloxy group, a carboxyl group, a mercapto group, and an organic group containing a group such as a hydroxyl group. Can be

In the present invention, among these groups, methyl, phenyl, γ-glycidoxypropyl, γ
-A (meth) acryloxypropyl group is preferred, and a methyl group is particularly preferred. R ^{2 is} also the same as R ^{2 in} Formula 1, and is an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, an isopropyl group, and a butyl group.
Ethyl groups are preferred. n is 0 or 1, r is 3 or 4, and n + r = 4. Monoalkoxysilanes and dialkoxysilanes with r = 1 or 2 may be used in combination, if necessary, in a range where the average of r is larger than 2.

Specific examples of the alkoxysilane include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltriisopropenoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane; n
-Propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltriisopropoxysilane,
n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, n-decyltrimethoxysilane, n-decyltriethoxysilane;

Phenyltrimethoxysilane, phenyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, trimethoxyhydrosilane, triethoxyhydrosilane; γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrisilane Ethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4
-Epoxycyclohexyl) ethyltriethoxysilane, γ (meth) acryloxypropyltrimethoxysilane, γ (meth) acryloxypropyltriethoxysilane;

Γ-aminopropyltrimethoxysilane,
γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, trifluoropropyltrimethoxysilane, and trifluoropropyltriethoxysilane No. These alkoxysilanes may be used alone or in combination of two or more.

Specific examples of the monoalkoxysilane and dialkoxysilane in which r is 1 or 2 include dimethoxydiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenylmethyldimethoxysilane, Phenylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyljetoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ -Aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, and the like.

The hydrolysis of the alkoxysilane for obtaining the polysiloxane resin used in the present invention is preferably carried out in a mixture of water containing an acidic hydrolyzable catalyst.
As the above-mentioned hydrolysis catalyst, pH is 2 to 5 upon contact with water.
The catalyst can be appropriately selected from known catalysts exhibiting acidic properties. In the present invention, it is particularly preferable to use a solid acid such as an acidic hydrogen halide, a carboxylic acid, a sulfonic acid, an acidic or weakly acidic inorganic salt, or an ion exchange resin.

Specific examples thereof include hydrogen fluoride, hydrochloric acid,
Organic acids typified by nitric acid, sulfuric acid, acetic acid, and maleic acid; methyl sulfonic acid; and cation exchange resins having sulfonic acid groups or carboxylic acid groups on the surface. Also,
The amount of the hydrolysis catalyst may be appropriately adjusted according to various uses, but in the present invention, the amount is preferably in the range of 0.001 to 5 mol% based on the alkoxysilane.

In the present invention, the amount of water in the hydrolysis reaction is 0.5 r molar equivalent to 1.5 r molar equivalent to the number r of alkoxy groups present in one molecule of the starting alkoxysilane.
It is preferably within the range of r molar equivalents. At 0.5 r molar equivalent or less, hydrolysis does not completely proceed, and an alkoxy group may remain excessively.At 1.5 r molar equivalent or more, excess water not involved in hydrolysis remains in the system,
Since the water content in the siloxane composition is increased, the storage stability may be lowered and the film forming property may be lowered.

The content of silanol groups in the hydrolyzed condensate of the alkoxysilane represented by the above formula (2) thus obtained must be within the appropriate range of q of 0.2 to 3. . When q is less than 0.2, the crosslink density at the time of curing decreases, and the hardness as a film becomes insufficient. When q is larger than 3, the cured product becomes high in hardness because the monomer and dimer of the alkoxysilane hydrolyzate are present in a large amount, but the appearance is poor such as cracks are easily formed. Become. Further, the amount p of the remaining alkoxy group after the hydrolysis condensation reaction needs to be in the range of 0 to 1. When p exceeds 1, the crosslinking density at the time of curing decreases and the hardness becomes insufficient, and in addition, the adhesion to the substrate decreases.

The organic solvent, which is an essential component in the composition of the present invention, is not only used as a diluent for controlling the solid content of the liquid, but also for reducing the silanol condensation reactivity. It is. Therefore, 10-35
It is necessary that the relative permittivity of the solvent in the temperature range of 4 ° C. is 4 to 16.

In a polar solvent having a relative dielectric constant exceeding 16 in a temperature range of 10 to 35 ° C., condensation is promoted due to a decrease in activation energy. It is known that silanol groups usually have a polarized structure represented by the following formula 1. Therefore, in a non-polar solvent having a relative dielectric constant of less than 4 such as toluene and xylene, the solubility of a resin having a highly polarized silanol group is extremely low, and even if dissolved, the silanol group alone is electrically unstable. Therefore, it is considered that condensation is promoted by approaching each other.

Embedded image

Examples of the organic solvent having a relative dielectric constant of 4 to 16 in a temperature range of 10 to 35 ° C. include a compound having a polarized substituent and a non-polar alkyl group and an aryl group. Ketones, esters, or ethers or alcohols having a lone pair of electrons having a polarized substituent such as a carbonyl group, and preferably containing an alkyl group having 3 or more carbon atoms. .

Specific examples thereof include ketones such as methyl isobutyl ketone (relative dielectric constant of 13.1, 20 ° C.) and esters such as isobutyl acetate (relative dielectric constant of 5.3, 20 ° C.). Ethers including tetrahydrofuran (dielectric constant 7.6, 25 ° C.), diisopropyl ether (dielectric constant 4.5, 25 ° C.), sec-
Butanol (dielectric constant 15.8, 25 ° C), tert-
Butanol (dielectric constant: 10.9, 30 ° C.), and ter
alcohols such as t-amyl alcohol (dielectric constant: 5.8, 25 ° C.) and the like;

In the present invention, tert-butanol, tert-amyl alcohol and methyl isobutyl ketone are particularly preferred, and tert-butyl alcohol and tert-amyl alcohol, which are polar organic groups having a bulky substituent, are particularly preferred. That is, the electrically polarized silanol group is in an equilibrium state where bonding and dissociation are repeated with many surrounding solvents. Therefore, when tert-butanol or tert-amyl alcohol having a bulky substituent forms a hydrogen bond with a silanol group,
The steric effect of the t-butyl group or the tert-amyl group makes it difficult for other silanol groups to approach, and also makes it difficult to take the pentacoordination state, which is a transition state of condensation, so that the condensation reaction is particularly inhibited. You.

The amount of the organic solvent used is 10
It is preferably in the range of 40 to 2,000 parts by weight with respect to 0 parts by weight. If the amount is less than 40 parts by weight, the resin concentration is too high and the viscosity becomes high to deteriorate the workability, and the silanol group becomes unstable and the condensation proceeds, which is not suitable.
If the amount exceeds 2,000 parts by weight, the solid content of the coating liquid is too low to obtain a cured film having a sufficient thickness, so that the performance is lowered.

In the present invention, organic solvents other than those described above can be used in combination as long as they do not affect the stability of the silanol group. For example, a combination of acid and basic compounds (such as acetic acid and sodium acetate, disodium hydrogen phosphate and citric acid) serving as a buffer for adjusting pH, a dispersing solvent, or for imparting excellent film performance , An organic resin, a pigment, a dye, a leveling agent, an ultraviolet absorber, a storage stabilizer and the like can be appropriately added and used.

The dispersion solvent may be used as long as the effects of the present invention are not impaired. From the viewpoint of the stability and availability of the sol, water or lower alcohols such as methanol, ethanol, isopropyl alcohol, n-butanol, isobutanol, and ketones such as methyl ethyl ketone (MEK) may be used as the dispersion solvent. Preferably, it is used. Further, in order to exert the above-mentioned solvent effect in the present invention, the water content in the composition is preferably 15% by weight or less. When the water content is 15% by weight or more, water is selectively coordinated with the silanol group, so that a hydrogen bond between the solvent and the silanol group is not generated, and the effect of stabilizing the silanol group is reduced.

Solvents other than the organic solvent which is preferably used in the composition of the present invention may be removed from the system by a means such as distillation under reduced pressure, if necessary, from the viewpoint of improving the stability after preparing the target liquid. It is preferable to remove to. For example, lower alcohols such as alcohols produced by hydrolysis of alkoxysilane as a raw material are preferably distilled off under reduced pressure as much as possible. In this case, it is preferable that a solvent contributing to stabilization of silanol is added in advance to make a dilute solution, and that the solution temperature is adjusted to a maximum of 40 ° C. and, if possible, the pressure is reduced to 30 ° C. or less.

In the composition of the present invention, the two major components of the alkoxysilane and the specific organic solvent are essential components. Depending on the use of the coating agent to be obtained, the hardness and the friction resistance of the cured film are determined. A known curing catalyst, metal oxide fine particles, and other additives may be appropriately contained in order to improve optical properties or impart optical functionality such as a high refractive index.

Specific examples of the curing catalyst include lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methylate, sodium acetate, potassium acetate, sodium formate, potassium formate, n-hexylamine, potassium propionate, and tributylamine. , Basic compounds such as diazabicycloundecene, tetraisopropyl titanate, tetrabutyl titanate, aluminum triisobutoxide, aluminum triisopropoxide, γ-
Aminopropyltrimethoxysilane;

Metal-containing compounds such as aluminum acetylacetonate, aluminum perchlorate, aluminum chloride, cobalt octylate, cobalt acetylacetonate, iron acetylacetonate, tin acetylacetonate, dibutoxytin octylate, p-toluene Acidic compounds such as sulfonic acid and tolchloroacetic acid are exemplified. The curing catalyst is preferably added in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the organopolysiloxane resin.

Specific examples of the metal oxide fine particles include silica, alumina, titanium oxide (TiO ₂ ), cerium oxide (CeO ₂ ), tin oxide (SnO ₂ ), zirconium oxide (ZrO ₂ ), and antimony oxide (Sb ₂ O ₅ ), iron oxide (Fe ₂ O ₃ ), titanium oxide doped with zirconium oxide, rare earth oxide, and the like. When a coating agent is used for the purpose of abrasion resistance, silica is particularly suitable. When used as a hard coat agent, the amount of the metal oxide fine particles to be added is preferably 5 to 500 parts by weight, particularly preferably 10 to 200 parts by weight, based on 100 parts by weight of the organopolysiloxane resin.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION The organopolysiloxane resin composition of the present invention has a mean composition formula of R ¹ _n Si (OR ² ) _p (O
_{H) q O (4-npq} ) / 100 parts by weight expressed siloxane resin _2, and, at least one having a relative dielectric constant within a temperature range of 10 to 35 ° C. is selected from the organic solvent is 4 to 16 Can easily be obtained by mixing 40 to 2,000 parts by weight of the organic solvent.

[0035]

The present invention improves the storage stability of an organopolysiloxane resin composition by including an organic solvent having a specific relative dielectric constant, so that it is not necessary to store at low temperature as in the past. Transportation and storage can be easily performed. By adding metal oxide fine particles, the organopolysiloxane resin composition of the present invention can be suitably used as a hard coat agent.

[0036]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.
Unless otherwise specified, “parts” and “%” described below mean “parts by weight” and “% by weight”, respectively.

Example 1.3 272 g (2.0 mol) of methyltrimethoxysilane and 157 g of methanol (dielectric constant: 32.6, 25 ° C.) were placed in a 1.3-liter flask, and ice-cooled under a nitrogen atmosphere to 10 ° C. It was as follows. Next, 0.1
144 g (8.0 mol) of an equivalent acetic acid aqueous solution was added dropwise over 40 minutes to hydrolyze methyltrimethoxysilane. After completion of the dropwise addition, the mixture was reacted for 1 hour under ice-cooling, and then stirred at room temperature for 3 hours to complete the hydrolysis.

To the obtained silanol solution, 191 g of methanol silica sol (silica solid content: 30% by weight) and te
600 g of rt-butanol was added, and the mixture was stripped under reduced pressure of 10 to 20 mmHg while keeping the internal temperature at 35 ° C. or lower, to distill off methanol and remaining water. The obtained silanol concentrate was 653 g.

To the obtained concentrated solution of silanol, tert-
111 g of butanol was added and the siloxane solid content was 25
% By weight. The ratio of methanol: tert-butanol in the solvent was measured by gas chromatography and found to be 10:90. A solution obtained by adding 0.5% by weight of sodium acetate to the siloxane solid content in this solution was used as a coating solution.

Embodiment 2 FIG. tert-butanol with ter
A siloxane solid content of 25% by weight was prepared in exactly the same manner as in Example 1 except that t-amyl alcohol was used, and a coating solution containing 8% by weight of methanol in a solvent was obtained. .

COMPARATIVE EXAMPLE 1.3 272 g (2.0 ml) of methyltrimethoxysilane and 157 g of ethanol (relative dielectric constant: 24.3, 25 ° C.) were placed in a 1.3-liter flask, and ice-cooled under a nitrogen atmosphere. And Then 0.1N
Acetic acid aqueous solution (144 g, 8.0 mol) was added dropwise over 40 minutes to effect hydrolysis. After completion of the dropwise addition, the mixture was reacted for 1 hour under ice cooling, and then stirred at room temperature for 3 hours to complete the hydrolysis.

191 g of methanol-silica sol (silica solid content: 30% by weight) was added to the obtained silanol solution, and the mixture was stirred at room temperature for 2 hours.
In addition, while keeping the internal temperature below 40 ℃, 30-40m
Under reduced pressure of mHg, methanol and ethanol were distilled off. This operation was repeated twice so that the siloxane solid content was 3
528 g of a 6.2% by weight silanol concentrated solution were obtained. Then, ethanol 23 was added so that the solid content was 25% by weight.
Upon addition of 7 g, the methanol: ethanol ratio in the solution was 12:88. Further, 0.5% by weight of sodium acetate based on the siloxane solid content was added as a curing catalyst to prepare a coating liquid.

Comparative Examples 2 and 3 Hydrolysis was carried out in exactly the same manner as in Comparative Example 1 except that ethanol used as the solvent for the alkoxysilane solution before hydrolysis was replaced with methanol, and solvent replacement by stripping was not performed. Was prepared. The coating solution of Comparative Example 3 was prepared by performing the hydrolysis in exactly the same manner as in Comparative Example 1, except that isopropyl alcohol was used instead of ethanol used as the solvent for the alkoxysilane solution before hydrolysis.

With respect to the storage stability of the coating solutions of Examples 1 and 2 and Comparative Examples 1 to 3 at a temperature of 25 ° C.,
The coating liquid immediately after preparation and after storage for one month after preparation was applied and cured, and the physical properties of the coatings were evaluated as described below for comparison. The results are as shown in Table 1 below. Incidentally, as the coating, a primer layer made of a thermosetting acrylic resin was applied to a polycarbonate plate and cured at 120 ° C. for 30 minutes, and then the coating liquid prepared above was applied and cured at 120 ° C. for 1 hour. Was used.

[0045]

[Table 1]

Evaluation method: Liquid appearance: A clear, colorless and transparent coating liquid was regarded as good, and a cloudy or white solid deposited was regarded as defective. -Coating appearance: The transparency of the obtained coating when the coating liquid was applied and cured was visually evaluated.

Pencil hardness: JIS: K-5400 No. 8.
The evaluation was performed according to section 4.2. Specifically, a pencil is firmly pressed at an angle of 45 degrees on the coating obtained by applying the coating liquid to a polished steel plate and curing at 120 ° C. for 1 hour, and pressing forward with a constant force to move the coating. Evaluation was made by the hardness (9H to 6B) of a pencil which forms a groove in the coating.

Adhesion: JIS: K-5400 6.1
The evaluation was performed according to five items. Specifically, a knife is applied to the coating with a knife.
Cuts at mm intervals were made to make a grid of 11 pieces each in the vertical and horizontal directions, and evaluation was made by the number of squares that were not peeled off when the cellotape (a product of Nichiban Co., Ltd.) was adhered and then peeled off. Scratch resistance: Using steel wool # 0000, the coating surface was rubbed 10 times with a load of 500 g, and the manner of scratching was visually judged. The criterion was evaluated as ○ when hardly scratched even when strongly rubbed, and as X when scratched.

Example 3.1 Into a one liter flask, 136 g (1.0 mol) of methyltrimethoxysilane and te
rt-butanol (dielectric constant: 10.9, 30 ° C.) 220
g was added thereto, and cooled to 10 ° C. or lower by ice cooling under a nitrogen atmosphere.
Next, 72 g (4.0 mol) of a 0.05N hydrochloric acid aqueous solution was added to 30
Hydrolysis was performed by dropping over a period of minutes. Then, the mixture was left under ice cooling for 30 minutes and stirred at room temperature for 2 hours to complete the hydrolysis.

²⁹ Si-NMR of the obtained hydrolyzate solution
(59.6 MHz) (FIG. 1). Next, the solution was applied on a glass substrate, dried at 60 ° C. for 15 minutes, and the solvent component was completely distilled off. The infrared absorption spectrum of the thin film formed was measured. When the residual amount of the methoxy group was quantified from the measurement result, it was 0.2% by weight (FIG. 2).

The two signals in FIG. 1 (-47 pp
m and -56 ppm) are assigned to a signal of a silicon atom having a hydroxyl group or a methoxy group. From these signal intensity ratios, the residual methoxy group and silanol group contents can be calculated, and the average composition formula MeSi (OM
_{e) P (OH) q O} (3-Pq) / 2 in the p + q is 0.6
3 (see Table 2 below).

[0052]

[Table 2] Chemical shift structure Abundance ratio ───────────────────────────── −47 ppm MeSi (OX) ₂ O _0.5 4.8 mol% −56 ppm MeSi (OX) ₁ O _1.0 53.5 mol% -64 ppm MeSiO _1.5 41.7 mol% ─

In FIG. 2, the broad absorption at 3,200 cm ^-1 is the stretching vibration of the hydrogen-bonding silanol group OH, and the extremely weak absorption at 2,840 cm ^{-1 is} the absorption of C--H in the methoxy group. It is derived from stretching vibration. Regarding the hydrolysis-condensation product of methyltrimethoxysilane, the amount of residual methoxy group can be quantified from the intensity ratio of the CH stretching vibration of the methyl group and the CH stretching vibration of the methoxy group.

From FIG. 2, since the methoxy group is estimated to be 0.2% by weight, the values of p and q can be calculated from MeSi (O
When calculated in _{Me) P (OH) q O} (3-Pq) / 2,
Since p is 0.01 or less and can be equal to 0, q = 0.63, and the average composition formula of the resin of Example 3 can be expressed as MeSi (OH) _0.63 O _1.19 .

While maintaining the silanol solution at 25 ° C., gel filtration chromatography (GPC)
The change in molecular weight distribution over time was followed to obtain a GPC curve immediately after hydrolysis (FIG. 3). The GPC curve in FIG. 3 is divided into T1 to T5 peaks due to the difference in the degree of polymerization. The greater the increase in molecular weight, the greater the silanol condensation reactivity. T4
And T5.

Example 4, Comparative Examples 4 to 7. tert-Butanol was prepared in accordance with Example 4 and Comparative Examples 4 to 7 by using tetrahydrofuran (dielectric constant 7.6, 2).
5 ° C.), methanol (dielectric constant 32.6, 25 ° C.), acetylacetone (dielectric constant 25.7, 20 ° C.), acetone (dielectric constant 20.7, 25 ° C.), and dioxane (dielectric constant 2. Hydrolysis was completed in the same manner as in Example 3 except that the temperature was changed to 2, 25 ° C). Next, while the obtained silanol solution was stored at 25 ° C., changes in the molecular weight distribution were monitored by GPC.

The changes in the molecular weight distribution in Examples 3 and 4 and Comparative Examples 4 to 7 are shown as T2 to T4 (A: square) and T5 or more (B) except for T1 in the GPC curve shown in FIG. :
A graph was formed using the change in peak area ratio over time (25 days) of two sets of diamonds (diamonds) (FIG. 4). In FIG. 4, the condensation of silanol groups gradually progresses with the passage of days,
It was observed that the ratio of A decreased and B increased due to the increase in molecular weight.

Therefore, the stability of the silanol group is as follows:
The larger the number of days, or the smaller the area difference between A and B on the 25th day, the larger, and the stability of the silanol group was judged from the change in each peak area. From the results, the polymerization rate of the silanol group-containing siloxane resin in each solvent was tert-butanol>
It was found that THF>dioxane>acetone> methanol ≒ acetylacetone.

Further, 95.7 g of methanol silica sol (solid content: 30%) was added to 428 g (solid content: about 20%) of the hydrolysis solution of Examples 3 and 4 and Comparative Examples 4 to 7, and the hydrolysis reaction was allowed to proceed completely. I let it. Next, except for the case of Comparative Example 4, since the methanol content of the solution was about 31%,
A solvent was appropriately added so that the total solid content of the final liquid was about 15% and the methanol content was 10% or less.

Next, the above-mentioned total hydrolysis solution including Comparative Example 4 was added to the solution for 10 to 20 while keeping the internal temperature at 35 ° C. or less.
The solvent was adjusted by stripping under reduced pressure of mmHg to remove methanol. In addition, since the organic solvent of Comparative Example 4 was methanol, the above-mentioned solvents did not have to be added. In Comparative Example 6, since the volatility of acetone was extremely high, first, a large amount of acetone was added. Pretreatment was carried out by stripping alone under the same conditions.

Further, a coating solution is prepared by adding 0.5% sodium acetate as a curing catalyst to the siloxane solid content, and the coating solution is applied to an aluminum substrate and cured by heating at 150 ° C. for 30 minutes to form a coating. Obtained. The storage stability of these coating solutions at 25 ° C. was compared by applying and curing the coating solutions immediately after preparation and after storage for one month after preparation, and evaluating the various physical properties of the coating in the same manner as the above-mentioned criteria. did. The results are as shown in Table 3 below.

[0062]

[Table 3]

Examples 5 and 6 and Comparative Examples 8 to 10. A 408 g of methyltrimethoxysilane was placed in a flask of 10.2 liters.
(3.0 mol) and 786 water at 0 ° C. under a nitrogen atmosphere.
g (43.7 mol) was added and mixed well. Then, under ice cooling, 216 g (12.0 mol) of a 0.05 N hydrochloric acid aqueous solution.
Was added dropwise over 40 minutes to effect hydrolysis. After completion of the dropwise addition, the mixture was stirred at 10 ° C. or lower for 1 hour and at room temperature for 2 hours to complete the hydrolysis.

The methanol produced by the hydrolysis was heated at 70 ° C.
The solution concentrated under reduced pressure at 60 mmHg for 1 hour and concentrated to 88% was cloudy and separated into two layers when allowed to stand overnight. After removing 996.6 g of water in the upper layer by decantation, the viscous polyorganosiloxane resin 240.g.
0 g was obtained. From the result of measuring ²⁹ Si-NMR of the obtained resin, it was calculated that the silanol group content was 7.8% (0.32 with respect to 1 atom of silicon) in the same manner as in Example 3.

The 10.0 g of the siloxane resin was added to each of Examples 5 and 6 and Comparative Examples 8 to 10,
0.0 g of tert-butanol, methyl isobutyl ketone, acetonilyl, acetone, and dioxane were added to prepare a silanol-containing siloxane resin solution. After storage at room temperature for 2 weeks, G
Table 4 shows the results of comparing the molecular weight distributions immediately after the solution preparation and two weeks after the preparation by PC.

[0066]

[Table 4]

Examples 7 and 8 and Comparative Examples 11 to 14. To 10.0 g of the silanol group-containing siloxane resin synthesized in the above Examples 5 and 6 and Comparative Examples 8 to 10, 40.0 g of tert-butanol, respectively, corresponding to Examples 7, 8 and Comparative Examples 11 to 14, tert-amyl alcohol,
An alcohol solution of methanol, isopropyl alcohol, n-butanol, and isobutanol was added to prepare a silanol-containing siloxane resin solution. 2 at room temperature
After storage for a week, GPC was performed in the same manner as in Example 3.
Table 5 shows the results of comparing the molecular weight distributions immediately after the preparation of the solution and two weeks later.

[0068]

[Table 5]

[Brief description of the drawings]

FIG. 1 shows ²⁹ S of a siloxane resin solution prepared in Example 3.
i-NMR chart.

FIG. 2 is an infrared absorption spectrum chart of a thin film prepared in Example 3 from which a siloxane resin solution was completely distilled off.

FIG. 3 is a GPC curve of the hydrolysis / condensation product of Example 3.

FIG. 4 is a graph showing the change over time in the ratio of the peak area of the GPC curve.

[Explanation of symbols]

 □: Peak area of T2 to T4 (A) ◇: Peak area of T5 or more (B)

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 83/06 C08L 83/06 C09D 183/06 C09D 183/06

Claims (3)

[Claims] An average composition formula, R ¹ _n Si (OR ² ) _p (OH) _q O
100 parts by weight of a siloxane resin represented by _{(4-npq) / 2} ,
And a relative dielectric constant of 4 within a temperature range of 10 to 35 ° C.
An organopolysiloxane resin composition comprising 40 to 2,000 parts by weight of at least one organic solvent selected from organic solvents of from 16 to 16. However, R in the above average composition formula
¹ is a hydrogen atom or an organic group having 1 to 18 carbon atoms, R
² is an alkyl group having 1 to 6 carbon atoms, n, p, and q are
0 ≦ n ≦ 1.8, 0 ≦ p ≦ 1, 0.2 ≦ q ≦
3, and a number that satisfies 0.8 ≦ n + p + q <4. 2. An organic solvent having a relative dielectric constant of 4 to 16 in a temperature range of 10 to 35 ° C. is a secondary alcohol,
The siloxane resin composition according to claim 1, wherein the siloxane resin composition is at least one selected from the group consisting of tertiary alcohols, ketones, and ether compounds. 3. The organic solvent having a relative dielectric constant of 4 to 16 in a temperature range of 10 to 35 ° C. is tert-butanol, tert-amyl alcohol, methyl isobutyl ketone (MIBK), and tetrahydrofuran (THF).
At least one selected from the group consisting of
The siloxane resin composition according to claim 2.