JP2001187863A - Urethane hard coating resin composition and coated material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide urethane hard coating resin compositions which inhibit foaming under hot and humid conditions and have sufficient working life, and coated materials. SOLUTION: The urethane hard coating resin compositions comprise (A) a compound composed of (a-1) a liquid bisphenol type epoxy ester modified polyol having two or more secondary hydroxy groups and (a-2) a natural oil or its derivative at a hydroxyl group equivalent % of (a-1) to (a-2) of 4/6 to 6/4 and (B) a polyisocyanate compound as the essential components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel urethane-based resin composition for hard coating and a coating material. More specifically, the present invention does not cause foaming of the coating film surface even under high temperature and high humidity, has good workability such as sufficient pot life, and furthermore, because it gives a hard resin cured product, harmful substances such as amines The present invention relates to a urethane-based hard coating resin composition and a coating material that can be used as a substitute for an epoxy resin containing a component.

[0002]

2. Description of the Related Art Urethane-based hard coating materials have been attracting attention as coating materials which have excellent extensibility and curability in winter and have no defects such as brittleness of commonly used epoxy materials and harmfulness of amines.

[0003] For example, as an example of a urethane-based hard coating agent, a polyurethane composition containing an alkylene oxide adduct of bisphenol A as a polyol component is disclosed. (Japanese Patent Publication No. 1-27109).

[0004] However, this technique is certainly useful as a hard flooring material, but has a drawback that the foaming phenomenon easily occurs particularly in summer, that is, under high temperature and high humidity conditions, so that it cannot be used throughout the seasons. In the summertime application of high temperature and high humidity, it hardens while generating carbon dioxide due to the reaction of water and isocyanate groups in the air and the base or in the system, which is a serious obstacle to obtaining a beautiful painted surface. This phenomenon is particularly remarkable in a portion where the coating thickness is small.

[0005] Furthermore, in general urethane coating materials, in many cases, hardness is generated by the formation of urea bonds, and it is necessary to use polyamines, which are harmful substances, and a hard type requires a large amount of polyamines. There are drawbacks such as the inability to secure the working time.

[0006] When the working time is shortened, it can be used in a method in which coating such as spray coating is completed in a short time,
It becomes difficult to use in hand coating work that requires time for application such as ironing and brush coating.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a urethane-based hard coating resin composition and a coating material which suppress foaming under high temperature and high humidity and have a sufficient pot life.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, the above-mentioned disadvantages have been improved by not using a highly hygroscopic component such as an alkylene oxide adduct of bisphenols. , Regardless of the environment,
Throughout the four seasons, a urethane-based hard coating composition and a coating material capable of always obtaining a beautiful coated surface have been completed.

That is, the present invention relates to (A) a liquid bisphenol-based epoxy ester-modified compound (a-1) having two or more secondary hydroxyl groups and a natural oil or its derivative (a-
Polyol obtained by mixing 2) so that the ratio of hydroxyl equivalent% becomes 4/6 to 6/4, and (B) a urethane-based hard coating resin composition and a coating material containing a polyisocyanate compound as an essential component It is about.

In particular, the present invention relates to (A) a liquid epoxy ester-modified polyol (a-1) having two or more secondary hydroxyl groups obtained by reacting a bisphenol-based epoxy compound with an unsaturated higher fatty acid, and a natural oil or a natural oil thereof. Polyol obtained by mixing the derivative (a-2) with a ratio of hydroxyl equivalent ratio of 4/6 to 6/4, and urethane-based hard coating resin containing (B) a polyisocyanate compound as an essential component It is intended to provide compositions and coatings.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The liquid epoxy ester-modified polyol as the component (a-1) is preferably a product obtained by reacting a bisphenol type epoxy resin having an epoxy equivalent of 160 to 700 with a higher fatty acid. And
A secondary hydroxyl group is preferentially generated by the reaction between the epoxy group of the epoxy resin and the carboxylic acid group of the higher fatty acid.

Due to the nature of the above reaction, the component (a-1) may contain a compound having a primary hydroxyl group, but does not impair the effects of the present invention.

The above-mentioned liquid epoxy ester-modified polyol refers to the compound which is liquid at room temperature, and (a-
1) As long as the component is liquid, it may be a mixture of a liquid and a solid epoxy ester-modified polyol.

If only typical representative examples of the bisphenol-type epoxy resin as the raw material of the component (a-1) are given, the compounds obtained by reacting epichlorohydrin with compounds of various bisphenols such as bisphenol A and bisphenol F may be used. These compounds are known and commonly used, and may be used alone or in combination of two or more.

On the other hand, as the higher fatty acid to be reacted with the bisphenol-type epoxy resin, a higher fatty acid having an ethylenically unsaturated bond and having 10 to 25 carbon atoms is preferable, and specific examples thereof include ricinoleic acid and oleic acid. , Linoleic acid, castor oil fatty acids such as linolenic acid,
Although soybean oil fatty acids and the like can be mentioned, more preferred are higher fatty acids having a hydroxyl group, and ricinoleic acid corresponds to them. Therefore, use of castor oil fatty acids is desirable.

When the fatty acid has less than 10 carbon atoms, the hydrophobicity of the polyol component is impaired, and the effect of improving the foaming of the coating film surface is reduced. When the fatty acid has more than 25 carbon atoms, the viscosity of the polyol component increases, Workability is significantly impaired.

If the higher fatty acid has an ethylenically unsaturated bond, the viscosity of the polyol is reduced and the polyol can be easily used as a coating agent. However, as long as the effects of the present invention are not impaired, lauric acid and palmitic acid are used. And higher fatty acids such as coconut oil fatty acids such as decanoic acid.

Furthermore, if the higher fatty acid has a hydroxyl group, the polyol obtained has a large number of functional groups, which is effective in hardening the urethane resin.

The hydroxyl group is preferably a secondary hydroxyl group, and a secondary hydroxyl group having a lower reactivity than the primary hydroxyl group is introduced into the polyol. Therefore, even if the number of functional groups is increased, a sufficient pot life as a coating material is maintained. be able to.

In this reaction, the reaction ratio between the epoxy group and the carboxylic acid group is preferably in the range of 1/1 to 1 / 0.7, more preferably in the range of 1 / 0.95 to 1 / 0.9. It is. When the ratio of the carboxylic acid group to the epoxy group is larger than 1, the carboxylic acid group remains, and foaming or the pot life is shortened. When the ratio is smaller than 0.7, the epoxy group and the carboxylic acid group The number of hydroxyl groups generated by the reaction (1) is reduced, which may undesirably affect the hardness development of the cured product.

At the end of the reaction, the acid value of the reaction mixture is 0.1.
5 (KOHmg / g) or less is preferable,
When the acid value is larger than 0.5, it is not preferable because the pot life as a coating material is shortened or a coating film is foamed.

The component (a-2), a natural oil or a derivative thereof, refers to a natural oil such as castor oil, soybean oil, and coconut oil, and derivatives thereof, and particularly has a secondary hydroxyl group. Castor oil and its derivatives are preferred.

The derivatives of natural oil referred to herein include, for example,
Examples include a transesterification product of a natural oil and a polyhydric alcohol (such as glycerol), a polymer of a natural oil, and a dicyclopentadiene adduct of a natural oil. Preferably, it is a derivative of castor oil, and examples thereof include a transesterification reaction product of castor oil and a polyhydric alcohol, a polymer of castor oil, and a dicyclopentadiene adduct of castor oil.

The ratio of the hydroxyl equivalent% in the component (A) means a ratio represented by the following formula. Formula (x / X) / (y / Y) x: parts by weight of component (a-1), X: hydroxyl equivalent of component (a-1) y: parts by weight of component (a-2), Y: ( a-2) Hydroxyl equivalent of the component

Here, the hydroxyl equivalent is calculated from all the hydroxyl groups in each component, and when a primary or tertiary hydroxyl group is contained in addition to the secondary hydroxyl group, these are also added together.

The mixing amount of the epoxy ester-modified polyol as the component (a-1) and the natural oil or the derivative thereof as the component (a-2) used in the present invention is as follows.
The ratio of the hydroxyl equivalent% of 1) and (a-2) is 4/6 to 6/4
When used in such a range, foaming of the coating film surface does not occur, and the physical properties of the cured product are improved, but when the component (a-1) is too large, the viscosity of the resin increases. Not only hinders workability,
Since the surface of the coating film foams, it is not preferable.
2) If the amount of the component is too large, the hardness and the physical properties decrease, which is not preferable.

On the other hand, if only typical representative examples of the polyisocyanate compound as the component (B) constituting the composition of the present invention are given, aliphatic, alicyclic or aromatic based polyisocyanate compounds can be used. Various polyisocyanates, or mixtures thereof.

Among them, first, hexamethylene diisocyanate (HDI) and the like are exemplified as particularly typical aliphatic polyisocyanates.
If only typical alicyclic polyisocyanates are exemplified, isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate (H ₁₂ MDI), etc., and particularly typical aromatic polyisocyanates Examples thereof include tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI) and polyphenylmethane polyisocyanate (crude MDI). Dimer compound, a trimer compound having a buret or isocyanurate structure, an addition reaction compound of the above-mentioned various diisocyanates with a polyol, and further, various modified products obtained by a known method. is there.

When yellowing resistance is not particularly important, use of aromatic polyisocyanates such as crude MDI and modified MDI is required in terms of price, coating workability, curability, and physical properties of the cured coating film. desirable.

The polyol component (A) includes the aforementioned (a)
In addition to -1) and (a-2), other polyols may be used as needed for the purpose of viscosity reduction or the like within a range that does not impair the effects of the present invention.

The hydroxyl groups of the other polyols described above need not be secondary hydroxyl groups as long as the effects of the present invention are not impaired.

Other polyols to be used include hydrophobic polyols such as polyol type xylene formaldehyde resin.

The other polyols here do not include short-chain polyols such as ethylene glycol and propylene glycol, and alkylene oxide polymers such as polyethylene glycol and polypropylene glycol.

The polyol type xylene formaldehyde resin has a multimolecular structure in which meta-xylene is linked by an alkylene, acetal, or ether bond, and has a xylene nucleus and a methylol group or a methoxymethyl group at its terminal. This polyol type xylene formaldehyde resin is obtained by introducing a methylol group, a methoxymethyl group, or the like into a terminal of a xylene formaldehyde resin obtained by reacting meta-xylene and formalin under a strong acid catalyst. Further, one or more compounds having active hydrogen such as phenols, carboxylic acids, amines, alcohols, or aromatic hydrocarbons at the above-mentioned reactive bonding group or terminal group in the xylene formaldehyde resin are used. May be contained. As described above, the polyol type xylene formaldehyde resin of the present invention is obtained by complexly introducing a third component into a xylene nucleus and modifying it.

The amount of the polyol type xylene formaldehyde resin used is 0 to 30 parts by weight, preferably 0 to 20 parts by weight, based on 100 parts by weight of the total of (a-1) and (a-2). The range is appropriate, and within this range, the pot life can be ensured, and it is effective in increasing the hardness of the final cured product, and is also effective in suppressing foaming.

On the other hand, the ratio of the isocyanate equivalent of the polyisocyanate to the hydroxyl equivalent of the compound (A) of the polyisocyanate (B), which is a curing agent component of the polyol (A), is 0.7-1. It is preferably used in an amount of 5 or less. When the amount is less than 0.7, the curing becomes insufficient. On the other hand, when the amount is more than 1.5, the coating film tends to become brittle and the physical properties deteriorate. It tends to be remarkable, and in any case, adversely affects physical properties and the like.

The coating material referred to in the present invention is obtained by adding various additives to the urethane-based hard coating resin composition of the present invention obtained as described above, with a filler as an essential component. .

Examples of the filler include calcium carbonate, surface-treated calcium carbonate, aluminum oxide, aluminum hydroxide, precipitated barium sulfate, clay, silica, and talc. Preferably, it is aluminum oxide.

As other additive components, organic or inorganic coloring pigments such as azo, copper phthalocyanine, red iron oxide, graphite, titanium oxide, zinc white or carbon black, and red lead, lead white, Rust preventive pigments such as basic chromate, basic lead sulfate, zinc chromate, zinc powder or MIO, and various assistants such as thixotropic agents, leveling agents, hygroscopic agents, silane or titanate coupling agents. Can also be added as needed.
Furthermore, if necessary, a curing catalyst such as an organometallic compound such as dibutyltin dilaurate or dibutyltin diacetate or various amines, dioctyl phthalate,
Asphalt or a plasticizer component such as tar or a petroleum diluent component such as heavy oil A or aromatic hydrocarbon may be used as long as the effects of the present invention are not impaired.
On the other hand, it doesn't hurt.

The above-mentioned fillers, additives and the like are mainly used by previously kneading the component (A) with a conventional mixing device.

The urethane-based resin composition for hard coating of the present invention thus obtained is useful as various industrial raw materials such as floor coverings, anticorrosion materials, waterproofing materials and the like. It is effective as an alternative high hardness coating material.

In using the coating material obtained by using the composition of the present invention, the components (A) and (B) are mixed at a predetermined mixing ratio (normal temperature), and the base material, for example, concrete, It is applied to metal, plastic, FRP, wood, etc. and cured, but in the present invention, it has a sufficient pot life that can be applied not only by spray coating but also by hand coating such as ironing or brushing. .

[0043]

EXAMPLES Next, the present invention will be specifically described with reference to Reference Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following, parts and%
All are by weight unless otherwise specified.

Reference Example 1 [Preparation Example of Polyol Component (A)] Forty parts by weight of a bisphenol A type epoxy resin having an epoxy equivalent of 188 and 60 parts by weight of castor oil fatty acid were added to 0.2 part by weight of triphenylphosphine. And an epoxy ester having an acid value of 0.1 and a hydroxyl equivalent of 265 [hereinafter abbreviated as epoxy ester (a-1-1)] obtained by reacting at 110 ° C. for 15 hours while bubbling with nitrogen in the presence of nitrogen. ] And 52 parts by weight of castor oil (a-2) having a hydroxyl equivalent of 350 were blended to obtain a polyol component (A) having a hydroxyl equivalent of 309. Here, the ratio of the hydroxyl equivalent% of the components (a-1-1) and (a-2) is
5.5 / 4.5.

Reference Example 2 [Same as above] 38 parts by weight of the epoxy ester (a-1-1) of Reference Example 1 and 62 parts by weight of castor oil (a-2) were blended to give a hydroxyl value equivalent of 318. The compound was obtained. Here, the ratio of the hydroxyl equivalent% of the components (a-1-1) and (a-2) is approximately 4.5 / 5.5.

REFERENCE EXAMPLE 3 [Same as above] 20 parts by weight of a bisphenol A type epoxy resin having an epoxy equivalent of 188, 20 parts by weight of a bisphenol F type epoxy resin having an epoxy equivalent of 171 and 60 parts by weight of castor oil fatty acid were added to triphenylphosphoric acid. 2 at 110 ° C. with nitrogen bubbling in the presence of 0.2 parts by weight of fins
Acid value 0.2 obtained by reacting for 4 hours, hydroxyl equivalent 27
0 epoxy ester [hereinafter, epoxy ester (a-
Abbreviated as 1-2). 49 parts by weight and a hydroxyl equivalent of 3
By blending 51 parts by weight of 50 castor oil (a-2), a target compound having a hydroxyl value of 312 was obtained. here,
The ratio of the hydroxyl equivalent% of the components (a-1-2) and (a-2) is 5.5 / 4.5.

Example 1 100 parts of the polyol component obtained in Reference Example 1, 40 parts of calcium carbonate, 50 parts of alumina, and 10 parts of pigment were uniformly mixed while vacuum degassing using a planetary mixer, and crude MDI was mixed with isocyanate. The mixture was sufficiently homogeneously mixed at a ratio of 1.15 of the equivalent to the hydroxyl group, and a performance test was performed using the cured product. Table 1 shows the results.

Regarding the evaluation of the surface foaming property of the coated surface, a moisture-curable urethane-based primer [Priadec T-150-35 (manufactured by Dainippon Ink and Chemicals, Inc.)] was used on a slate plate.
Was applied and cured under the conditions of a temperature of 35 ° C. and a humidity of 80%, and the presence or absence of bubbles generated on the surface was evaluated. In addition,
The results of the physical property tests are values obtained after mixing the above-mentioned compound containing the component (A) and the component (B) and curing at 25 ° C. for 7 days. (JIS-K-6301).

Examples 2 and 3 Examples 2 and 3 were carried out in the same manner as in Example 1 using the polyol components of Reference Examples 2 and 3, respectively. The results are also shown in Table 1.

[0050]

[Table 1] Table 1 Results of Examples 1 to 3 1 Viscosity of the compound containing the polyol component (A) 2 Viscosity immediately after mixing the compound containing the component (A) and the component (B) 3 After mixing the compound containing the component (A) and the component (B), 50,000 mPa · time to reach s

Comparative Example 1 30 parts by weight of the epoxy ester (a-1-1) of Reference Example 1 and 70 parts by weight of castor oil (a-2) were blended to obtain a compound having a hydroxyl equivalent of 325. Here, the ratio of the hydroxyl equivalent% of the components (a-1-1) and (a-2) is
It becomes approximately 3.5 / 6.5, which is a value that impairs the effect of the present invention. Table 2 shows the results of the same evaluation as in Examples 1 to 3. Although no surface foaming is observed, a hardness sufficient to be regarded as hard urethane cannot be exhibited.

Comparative Example 2 58 parts by weight of the epoxy ester (a-1-1) of Reference Example 1 and 42 parts by weight of castor oil (a-2) were blended to obtain a compound having a hydroxyl equivalent of 302. Here, the hydroxyl equivalent% of the component (a-1-1) and the castor oil (a-2)
Is approximately 6.5 / 3.5, which is a value that impairs the effect of the present invention. Table 2 shows the results of the same evaluation as in Examples 1 to 4. Hardness can be expressed as hard urethane, but surface foaming occurs.

Comparative Example 3 In place of the epoxy ester polyol (a-1-1), a propylene oxide adduct of bisphenol A (a-
Using 1-3), a polyol component (A) was prepared by blending with castor oil (a-2). Example 1 using this
Table 2 shows the results of the same evaluation. Hardness that can be said to be hard urethane can be exhibited, but surface foaming occurs due to the inclusion of raw materials having high hygroscopicity.

Comparative Example 4 Half of the epoxy ester polyol (a-1-1) was prepared by adding bisphenol A adduct of propylene oxide (a-1).
The polyol component (A) was prepared by blending with the castor oil (a-2) using the component (a-1) replaced with the component (-3). Table 2 shows the results of the same evaluation as in Example 1 using this. When a highly hygroscopic raw material is used in combination with the component (a-1), surface foaming occurs.

[0055]

Table 2 Table 2 Results of Comparative Examples 1-4 1 (a-1-1) / (a-1-3) / (a-2) = 3/3/4 2 Viscosity of Compound Containing Polyol Component (A) 3 Compound Containing (A) Component and (B) ) Viscosity immediately after mixing the components 4 Time until the compound containing the component (A) and the component (B) are mixed and reaches 50,000 mPa · s

Comparative Example 5 40 parts by weight of a bisphenol A type epoxy resin having an epoxy equivalent of 188 and 60 parts by weight of 12-hydroxystearic acid which is a fatty acid having no ethylenically unsaturated group were mixed with triphenylphosphine. An epoxy ester having an acid value of 0.2 and a hydroxyl equivalent of 280 obtained by reacting at 110 ° C. for 16 hours while bubbling with nitrogen in the presence of 0.2 parts by weight becomes waxy at room temperature and can be blended with castor oil. It had high viscosity and was difficult to use. Thus, it is difficult to use a composition that does not contain a bisphenol-based epoxy ester-modified polyol that is liquid at room temperature.

As is clear from Table 1, the present invention has improved the foaming phenomenon of the two-pack type urethane resin composition.
Even when applied under high temperature and high humidity, a hard coated surface containing no air bubbles can be obtained.

[0058]

The urethane resin composition of the present invention has a very low foaming property even under high temperature and high humidity, has a sufficient pot life, and gives a hard resin cured product, so that harmful substances such as amines can be obtained. It is possible to obtain a urethane-based hard coating resin composition that can be used as a substitute for an epoxy resin containing components.

Claims (4)

[Claims] (A) a liquid bisphenol-based epoxy ester-modified polyol having two or more secondary hydroxyl groups (a-1) and a natural oil or a derivative thereof (a-2); A urethane-based hard coating resin composition comprising, as an essential component, a compound characterized in that the ratio of the hydroxyl equivalent% of (a-2) is 4/6 to 6/4, and (B) a polyisocyanate compound. 2. The urethane-based hard coating resin composition according to claim 1, wherein the liquid bisphenol-based epoxy ester-modified polyol (a-1) comprises a reaction product of a bisphenol-based epoxy compound and a higher fatty acid. object. 3. The urethane-based hard coating resin composition according to claim 2, wherein the higher fatty acid is a fatty acid having 10 to 25 carbon atoms having at least one ethylenically unsaturated group. 4. A urethane-based hard coating comprising the resin composition according to claim 1.