JPH0786182B2 - Coating resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial field of application The present invention is suitable as a surface-protecting coating agent for daily use, industrial equipment, etc. by forming a coating film excellent in various properties by curing at room temperature in a short time. The present invention relates to a coating resin composition that can be used for.

Conventional techniques and problems to be solved by the invention Conventionally, coating resin compositions are, for example, furniture, furniture, floors, wood, metal plates, various building materials, home appliances, outside and inside of houses, exteriors of automobiles, etc. , It is used as a coating agent for protecting the surfaces of these objects by coating them from daily commodities to various equipment such as industrial equipment and transportation. In this case, the surface protection by the coating resin composition is to prevent scratches, corrosion, contamination, and
It is carried out for the purpose of preventing deterioration due to ultraviolet rays, seawater, and wind and rain.

However, when the coating resin composition is cured at a low temperature for a short time, the hardness of the obtained coating becomes low or becomes brittle. Therefore, in order to increase the hardness of the coating and impart a certain strength, the coating resin composition is cured. It is necessary to raise the temperature and cure for a long time. Therefore, it is difficult to move the object after coating in a short time or to move to the next step, and the conventional coating resin composition has poor workability.

Therefore, it has been desired to develop a coating resin composition having good workability and forming a high-performance coating.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coating resin composition which is cured at a low temperature in a short time to form a film having high hardness and high performance.

Means and Actions for Solving the Problem As a result of intensive studies to achieve the above-mentioned object, the present inventor has (A) an acid containing two or more hydrogen atoms as an acid group in one molecule and / or Organo of the general formula (I) described below, which contains the anhydride and (B) at least one epoxy group reactively bonded to the hydrogen atom of the component (A) in one molecule and a hydrolyzable group. A silane or organopolysiloxane or a partial hydrolyzate or partial hydrolyzate thereof, and (C) an organosilane of the following general formula (II) containing at least two or more hydrolyzable groups in one molecule. Alternatively, by using three components of organopolysiloxane or a partial hydrolyzate or a partial cohydrolyzate thereof, it is cured at room temperature in a short time and becomes tack-free. Excellent workability, high hardness and scratch resistance, and excellent water resistance, boiling water resistance, salt water resistance, solvent resistance, wear resistance, stain resistance, weather resistance, flex resistance and surface gloss. The inventors have found that a coating resin composition capable of forming a good film can be obtained, and have completed the present invention.

That is, in the conventional coating resin composition, usually, the hydrolyzable functional groups present in the components are hydrolyzed and condensed by the moisture in the air in the presence of a condensation catalyst such as an acid, an amine or an organic acid salt of a metal. Although it is polymerized and cured, it is difficult to cure it at room temperature in a short time by this curing mechanism, and it is difficult to obtain a film having good performance. On the other hand, the coating resin composition of the present invention comprises an organosilane or organopolysiloxane having an epoxy group as the component (B) and having a hydrolyzable functional group bonded to a silicon atom or a portion thereof. In the presence of a reactant formed by the epoxy group in the (co) hydrolyzate reacting with the hydrogen atom as the acid group in the acid of the component (A) and / or its anhydride, (B), ( The hydrolyzable group in the organosilane or organopolysiloxane or the partial (co) hydrolyzate of the component C) is hydrolyzed and condensed by addition of moisture or water in the air to form a three-dimensional structure, and thus cured. In addition to rapidly curing at room temperature, it forms a film having high hardness, toughness and excellent performance.

Therefore, the present invention provides (A) an acid and / or an anhydride thereof containing two or more hydrogen atoms as an acid group in one molecule, and (B) the following general formula (I). (However, in the formula, R ¹ is R ² is an alkylene group having 1 to 5 carbon atoms, R ³ is a group selected from an alkyl group having 1 to 8 carbon atoms, an alkenyl group and an aryl group, R ⁴ is an alkyl group having 1 to 5 carbon atoms, m is
It is 0, 1 or 2. ) An organosilane represented by the formula (1) or an organopolysiloxane containing one or more organosilanes represented by the above formula (I) in one molecule as a part of the polymer, or a partial hydrolyzate or a partial cohydrolyzate thereof, C) The following general formula (II) R ³ _n Si (OR ⁴ ) _4-n (II) (wherein R ³ and R ⁴ are the same as described above, and n is 0, 1 or 2)
Is. ) Or an organopolysiloxane containing at least one organosilane represented by formula (II) or one of the above formulas (II) in one molecule as a part of the polymer, or a partial hydrolyzate or partial hydrolyzate thereof is essential. A coating resin composition characterized by being used as a component.

Hereinafter, the present invention will be described in more detail.

The component (A) of the present invention is an acid containing two or more hydrogen atoms in one molecule as an acid group capable of reacting with an epoxy group and / or an anhydride thereof, and examples thereof include orthophosphoric acid and polyphosphoric acid. Acid, maleic anhydride, adipic acid, sebacic acid, phthalic anhydride, isophthal, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6
-Endomethylenetetrahydrophthalic anhydride, trimellitic anhydride and the like. Of these, orthophosphoric acid, polyphosphoric acid, adipic acid, phthalic anhydride, terephthalic acid, and trimellitic anhydride are preferable in the present invention.
In particular, orthophosphoric acid and polyphosphoric acid are most preferably used.

In this case, the acid of the component (A) and / or its anhydride is a compound in which a hydrogen atom as an acid group thereof reacts with an epoxy group in the organosilane or organopolysiloxane of the component (B) described later to be bonded. In particular, orthophosphoric acid and polyphosphoric acid have good reactivity with the epoxy group in the component (B) and have the advantage that this reaction is almost completed in the temperature range of room temperature to 70 ° C. The coating resin composition containing the compound has a pencil hardness of 5H in pencil hardness.
It has a high hardness of ~ 9H and forms a film with extremely excellent performance.

Next, as the organosilane or organopolysiloxane having at least one epoxy group and a hydrolyzable group in one molecule which is the component (B) of the present invention, the following general formula (I) can be used. (However, in the formula, R ¹ is R ² is an alkylene group having 1 to 5 carbon atoms such as methylene group, ethylene group, propylene group, butylene group, pentylene group, R ³
Is a methyl group, ethynyl group, phenyl group, etc., having 1 to 8 carbon atoms
Is a group selected from an alkyl group, an alkenyl group and an aryl group, R ⁴ is an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group, and m is 0, 1 or 2. ) Or an organopolysiloxane containing one or more of the organosilane represented by the formula (1) or the organosilane of the above formula (I) in one molecule as a part of the polymer is used. The organosilane of the formula (I) or the organopolysiloxane having the formula (I) of the organosilane as a unit formula is such that the epoxy group contained in these compounds is a hydrogen atom as an acid group in the compound of the component (A). The alkoxy group (—OR ⁴ group) bonded to the silicon atom reacts easily with water and is easily hydrolyzed to cause polycondensation.
It is suitable as a component.

Specific examples of such an organosilane or organopolysiloxane include the following formulas (i) to (x). Examples thereof include compounds of formula (i) and formula (iv)
Compounds of formula are preferably used.

Further, the component (B) may be a partial hydrolyzate or partial cohydrolyzate of the above-mentioned organosilane or organopolysiloxane.

In addition, the said (B) component may be used individually by 1 type or in mixture of 2 or more types.

The blending ratio of the component (B) is such that the epoxy group of the component (B) is 0.1 equivalent to 1 equivalent of hydrogen atom as the acid group of the component (A).
The compounding ratio is preferably 6 to 1.4 equivalents, particularly 0.9 to 1.1 equivalents. If the compounding ratio is less than 0.6 equivalents, the acid groups of the component (A) will be in excess and remain as it is, so the performance of the coating such as water resistance and boiling water resistance will deteriorate.
The surface hardness of the coating may decrease, and if the compounding ratio exceeds 1.4 equivalents, residual epoxy groups in the reaction may remain in the coating, and the performance of the coating, particularly stain resistance and weather resistance, may decrease.

Further, the component (C) of the present invention contains at least 2 in one molecule.
An organosilane or organopolysiloxane containing at least one hydrolyzable group, represented by the following general formula (II) R ³ _n Si (OR ⁴ ) _4-n ... (II) (wherein R ³ , R ⁴ is the same as above, and n is 0, 1 or 2
Is. ) Or an organopolysiloxane containing at least one organosilane represented by the formula (2) or the organosilane represented by the above formula (II) in one molecule as a part of the polymer is used.

Specific examples of such organosilane or organopolysiloxane include methyltrimethoxysilane, ethyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane,
Examples include phenyltriethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, diphenyldimethoxysilane, dimethyldiethoxysilane, methylphenyldiethoxysilane, orthomethylsilicate, orthoethylsilicate, and further by partial hydrolysis of these compounds. It is also possible to use a condensate, a condensate obtained by partial cohydrolysis, and the like.

As the component (C), methyltrimethoxysilane, phenyltrimethoxysilane, and their partial hydrolysates and condensates by partial cohydrolysis are particularly preferred because of their fast curing reaction rate and high crosslinking density. Is. Furthermore, by blending orthomethyl silicate, orthoethyl silicate, or a condensate thereof by partial (co) hydrolysis with these compounds, it is possible to make the coating harder, and to impart toughness and softness to the coating. In this case, it is preferable that dimethyldimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, or a condensate of partial (co) hydrolysis thereof be mixed in an appropriate mixing ratio.

The blending ratio of the component (C) varies depending on the type of organosilane or organopolysiloxane, but 1 component of the component (C) is added to 100 parts by weight of the total amount of the components (A) and (B).
It is preferably 0 to 1000 parts by weight, particularly preferably 30 to 350 parts by weight.

When the amount of the component (C) is less than 10 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B), the hardness of the coating tends to be soft, and the weather resistance and water resistance are The performance may be deteriorated and the coating may have poor wear resistance. When the amount of the component (C) is more than 1000 parts by weight, the hardness of the coating becomes hard, but the toughness is lacking and cracks are likely to occur.

The coating resin composition of the present invention has the above (A) to
The component (C) can be mixed by a generally known method to prepare a coating agent.

Here, as a preparation method, for example, the component (A) and the component (B)
After reacting the components with an organic solvent such as alcohol,
A method of adding component C) and further adding water for hydrolysis;
After partially co-hydrolyzing the component (B) and the component (C) in advance, an organic solvent such as alcohol is added, and then the component (A) is added to convert a hydrogen atom as an acid group in the component (A) to ( Method of reacting with epoxy group in component B), components (A) to (C) are simultaneously added to a suitable solvent, and reaction of component (A) and component (B) is added while dripping water, (B) A method of simultaneously performing a cohydrolysis reaction of the component and the component (C),
The component (B) and the component (C) are partially hydrolyzed and then mixed, and then the component (A) is added via an organic solvent such as alcohol to partially hydrolyze the component (A) and the component (B). The method of reacting with can be adopted, the use of the composition, the required performance of the coating, the state of the manufacturing apparatus,
It can be prepared by a suitable method among them depending on the kind of the components (A) to (C).

Further, the coating resin composition of the present invention can be used as a coating agent by mixing the components (A) to (C) in advance and storing them as a one-component system (one pack). The system consists of (A) to (C) component types,
The storage stability may be deteriorated depending on the conditions such as the compounding ratio and the amount of water used for partial cohydrolysis. in this case,
The storage stability is improved by reducing the amount of water used for partial cohydrolysis, but the hardening of the coating is delayed, the target hardness is not reached, and the surface hardening rate of the coating is faster than that of the inside. As the speed increases, the surface tends to have fine wrinkles. Therefore, in order to eliminate such storage stability and defects on the surface of the coating film, it is preferable that the composition of the present invention is stored as a two-component system (1 pack) and mixed and used at the time of coating.

Here, as a method of making the composition of the present invention into a two-component system,
For example, the component (B) and the component (C) are partially cohydrolyzed in an organic solvent with a water content smaller than a predetermined amount to obtain a prepolymer in advance, while the component (A) has a water content of a shortage or more, which is necessary. According to the method of preparing a two-component system by adding an organic solvent according to the method, a mixed solution of both components (A) and (B) and a solvent, and a mixed solution of a solvent of (C) and water. There is a method of using a two-component system, and this method is particularly suitable when the component (A) is orthophosphoric acid, polyphosphoric acid or the like which easily reacts with the epoxy group in the component (B) at room temperature. .
In addition, such a two-component system has good storage stability of the prepolymers of the components (B) and (C), and the mixed solution containing the component (A) has little change with time and can be stably stored. it can. Further, the two-component system is easy to use without the drawback that the one-component system is likely to occur in the one-component system in which the gelled product of the coating agent adhering to the periphery of the outlet of the container is mixed into the coating agent during use.

The reaction between the hydrogen atom as the acid group in the component (A) and the epoxy group in the component (B) is carried out in an organic solvent such as methanol, ethanol, isopropanol, isobutanol, n.
-Alcohols such as butanol, ketones such as acetone, esters, aromatic hydrocarbons, it is preferable to carry out in the presence of halogenated hydrocarbons, the reaction conditions are not particularly limited, but 20 ℃ It is preferable to react for 1 hour or more. In this case, a required amount of a reaction catalyst such as ethylenediamine can be added if necessary.

In addition, in the hydrolysis when preparing the composition,
The amount of water required for hydrolysis is not particularly limited, but it is preferable that the amount of water is such that the composition does not form a gel in the condensation reaction due to hydrolysis. Usually, the molar amount of the hydrolyzable group in all components is It is desirable that the molar amount of water corresponds to about 50% or less of the number.

When the coating resin composition of the present invention is used as a coating agent, it is preferably diluted with a solvent after preparation so that it can be easily applied to an object to be coated.

Here, as the solvent, for example, alcohols such as methanol, ethanol, isopropanol, isobutanol, n-butanol and the like are preferable, but other solvents such as ketones, esters, aromatic hydrocarbons and halogenated compounds are preferable. Hydrocarbons and the like can also be used. The above alcohols have extremely low solubility in coating films composed of plastics and various resins as compared with other solvents, and do not attack various metal surfaces. Therefore, coating agents diluted with alcohols are used. Has a wide range of applications.

Thus, the coating resin composition of the present invention comprises the above components (A) to (C), and in the present invention, a hydrogen atom as an acid group in the component (A) ( In the presence of a reaction conjugate with the epoxy group in component B),
In the presence of water, the hydrolyzable groups in the components (B) and (C) are hydrolyzed and polycondensed to form a three-dimensional structure, which is a cured product.

The coating resin composition of the present invention is cured at room temperature in a short time and becomes tack-free, and the surface temperature of the coating becomes high in a short time. Therefore, the work efficiency is good and the productivity is improved. Moreover, the cured film has a high hardness, the surface is not easily scratched, and it is excellent in water resistance, boiling water resistance, solvent resistance, further abrasion resistance, stain resistance, weather resistance, flex resistance,
The surface hardness is also good, and the coating film formed by the coating resin composition of the present invention is useful for surface protection of various objects such as daily necessities and industrial equipment.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following examples, all parts are parts by weight.

[Examples 1 to 9] With the compounding amounts shown in Table 1, the orthophosphoric acid of component (A) (purity
(85% product), ylpropanol was added as a solvent, γ-glycidoxypropyltrimethoxysilane as the component (B) was further added, and the reaction was carried out at 40 ° C for about 2 hours. next,
As the component (C), one or more of methyltrimethoxysilane, phenyltrimethoxysilane, ylpropyltrimethoxysilane, dimethyldimethoxysilane, and ethylsilicate are blended as shown in Table 1 and partially cohydrolyzed. After adding the required amount of water to and performing partial co-hydrolysis, add isopropanol to obtain a nonvolatile content of 30%.
And a coating agent was obtained.

The properties (appearance, nonvolatile content, viscosity) of the obtained coating agent are also shown in Table 1.

Further, this coating agent was applied onto a transparent glass plate to obtain a coating film having a film thickness of 15 μm, and the performance of this coating film was evaluated by the following method. The results are also shown in Table 1.

(A) Drying property (tack-free) In a room at 25 ° C-60% RH, the time was measured when the fingerprint was no longer touched with the finger.

(B) Hardness According to JIS K-5400, the hardness was measured 1 hour and 6 hours after coating, and evaluated by pencil hardness.

(C) Water resistance The water resistance after immersion in water at 25 ° C for 7 days was evaluated.

(D) Boiling water resistance The boiling water resistance after immersion in boiling water for 2 hours was evaluated.

(E) Solvent resistance Toluene and acetone are used as the solvent,
The state after immersion for 30 minutes was observed.

From the results shown in Table 1, the coating resin composition of the present invention has good properties, cures at room temperature for a short time, and forms a coating film having high hardness, water resistance, boiling water resistance, and solvent resistance. I found out that

[Examples 10 to 12] Isobutanol was added as a solvent to orthophosphoric acid (85% purity product) in the compounding amounts shown in Table 2, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane was further added. The reaction was carried out at 50 ° C for about 1 hour. Next, as a component (C), methyltrimethoxysilane, phenyltrimethoxysilane or a partial cohydrolyzate of methyltrimethoxysilane 60 mol% and phenyltrimethoxysilane 40 mol% (average degree of polymerization 3) is blended, After adding water necessary for partial cohydrolysis, ethanol was added so that the nonvolatile content was 30%.

The properties of the obtained coating agent and the performance of the coating film are also shown in Table 2.

From the results shown in Table 2, it was found that the coating agent of the present invention has good properties and the resulting coating film has very excellent performance.

Example 13 Trimellitic anhydride To 19.2 parts, add 40 parts of acetone and 100 parts of isopropanol, 0.1 part of ethylenediamine as a reaction catalyst, add 70.8 parts of γ-glycidoxypropyltrimethoxysilane while stirring, and further add 50 parts of methyltrimethoxysilane to sufficiently add. After mixing, 12 parts of water was added dropwise with stirring, the temperature was raised to 76 ° C., and the mixture was reacted under reflux for 3 hours. Next, acetone, condensed methanol, isopropanol and the like were stripped, and 130 parts of isopropanol was added to form an isopropanol solution. As a result, a colorless transparent liquid having a nonvolatile content of 43% and a viscosity of 32 cs was obtained.

The obtained liquid was applied on a glass plate to form a coating film. This coating film was a colorless transparent smooth film having a film thickness of 13 μm, which was tack-free in 25 minutes at 25 ° C., and had a pencil hardness of 5H after 6 hours. When the water resistance, solvent resistance and boiling water resistance were evaluated in the same manner as in Example 1, good results were obtained, and no change was observed in the state and appearance of the coating film before the test.

Example 14 10 parts of polyphosphoric acid (average degree of polymerization 5, molecular weight 418) was dissolved in 400 parts of ylpropanol, 84.5 parts of γ-glycidoxypropyltrimethoxysilane was added thereto, and the mixture was reacted at 40 ° C. for 3 hours. After that, 90 parts of methyltrimethoxysilane was added and mixed, and 18.4 parts of water was added for partial cohydrolysis.

The obtained coating agent was a colorless transparent solution, which was a liquid having a nonvolatile content of 32% and a viscosity of 9.3cs.

Further, this coating agent was applied onto a transparent glass plate to obtain a transparent coating film having a film thickness of 15 μm. The time required for this coating to become tack-free was 25 ° C for 5 minutes, and after 1 hour the hardness showed a pencil hardness of 8H, and after 6 hours it became a hard, smooth and glossy coating of 9H. It was Further, when the water resistance, boiling water resistance and solvent resistance of the coating film were evaluated in the same manner as in Example 1,
No abnormalities were observed.

[Comparative example]

70 parts of ylpropanol, 61.4 parts of γ-glycidoxypropyltrimethoxysilane and 61.4 parts of methyltrimethoxysilane
The resulting mixture was mixed, 14.3 parts of water and 0.5 part of glacial acetic acid were added, and partial cohydrolysis was carried out at 60 ° C. for about 3 hours. Then, ylpropanol was added to adjust the nonvolatile content to 30%.

The resulting solution is colorless and transparent, has a nonvolatile content of 30.1% and a viscosity of 5.0cs.
It was a liquid.

Furthermore, the coating film prepared by applying this solution on a glass plate had a tack-free time of 90 minutes at 25 ° C., and the hardness of the coating film after 3 hours was 3H. The solvent resistance of the coating film was opaque and slightly swollen with both acetone and toluene for 30 minutes, and the boiling water resistance was such that the coating film was whitened 1 hour after immersion and completely devitrified. The results were inferior to those of Examples 1 to 14.

Claims (1)

[Claims] 1. (A) an acid and / or an anhydride thereof containing two or more hydrogen atoms as an acid group in one molecule, and (B) the following general formula (I): (However, in the formula, R ¹ is R ² is an alkylene group having 1 to 5 carbon atoms, R ³ is a group selected from an alkyl group having 1 to 8 carbon atoms, an alkenyl group and an aryl group, R ⁴ is an alkyl group having 1 to 5 carbon atoms, m is
It is 0, 1 or 2. ) An organosilane represented by the formula (1) or an organopolysiloxane containing one or more organosilanes represented by the above formula (I) in one molecule as a part of the polymer, or a partial hydrolyzate or a partial cohydrolyzate thereof, C) The following general formula (II) R ³ _n Si (OR ⁴ ) _4-n (II) (wherein R ³ and R ⁴ are the same as described above, and n is 0, 1 or 2)
Is. ) Or an organopolysiloxane containing at least one organosilane of the formula (II) or one part of the polymer per molecule as a part of the polymer, or a partial hydrolyzate or a partial cohydrolyzate thereof is an essential component. And a coating resin composition.