JP5545556B2 - Epoxy resin and epoxy resin composition using the same - Google Patents

Description

  The present invention relates to an epoxy resin having excellent anticorrosion properties and excellent curability even in a low temperature environment, and further relates to an epoxy resin composition using the epoxy resin.

  At present, an epoxy resin added with an amine-based curing agent is used as an anticorrosion paint because it is excellent in anticorrosion and adhesiveness. One such application is paint for ship ballast tanks. However, this epoxy resin anticorrosive coating has a problem that it has a low curability in a low temperature environment (0 to 5 ° C. in winter) and takes a long time for construction. Therefore, the current situation is that an epoxy urethane resin (epoxy polyol-polyisocyanate type) using a polyisocyanate having high low-temperature curability is used in place of an epoxy resin for construction in a low temperature environment. However, compared to ordinary epoxy resins, epoxy urethane resins use polyisocyanates, so the degradation of polyisocyanates due to moisture, foaming in the coating film due to carbon dioxide generated by the decomposition, and corrosion resistance are insufficient. There is a problem that there is. Moreover, since the epoxy polyol has a large molecular weight, there is a problem that it is difficult to form a high solid.

  Accordingly, there is a need for an anti-corrosion paint of epoxy resin that does not use polyisocyanate that is highly curable even in a low temperature environment. In order to improve the low-temperature curability of the epoxy resin, an epoxy resin composition using an amine-based curing agent obtained by epoxy-modifying a Mannich reaction product (for example, see Patent Document 1) or an epoxy resin and a trifunctional or higher functional acrylate compound. An epoxy resin composition (for example, refer to Patent Document 2) using a combination of the above and the like has been proposed. However, even these epoxy resin compositions do not have sufficient low-temperature curability, and further higher low-temperature curability is required.

JP-A-11-172195 JP 2002-256139 A

  The problem to be solved by the present invention is to provide an epoxy resin that is excellent in corrosion resistance and excellent in curability even in a low temperature environment, and further to provide an epoxy resin composition using the epoxy resin.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have obtained an epoxy resin excellent in low-temperature curability by using an epoxy resin obtained by urethane- (meth) acrylate-forming a hydroxyl group of an epoxy resin having a hydroxyl group. The inventors found that a composition can be obtained and completed the present invention.

  That is, the present invention relates to an epoxy resin characterized in that a hydroxyl group of an epoxy resin having a hydroxyl group is urethane (meth) acrylated with a compound having a (meth) acryloyl group and an isocyanate group, and an epoxy resin composition using the same It provides things.

  The epoxy resin of the present invention is suitable as a resin for anticorrosion coatings to be applied in a low temperature environment because it is excellent in anticorrosion, adhesiveness, and low temperature curability. Moreover, the epoxy resin composition using the epoxy resin of the present invention is useful as an anticorrosion paint for ships, an anticorrosion paint for steel structures such as bridges, and particularly useful as an anticorrosion paint for the inner surface of a ballast tank.

  The epoxy resin of the present invention is an epoxy resin obtained by converting a hydroxyl group of an epoxy resin having a hydroxyl group into a urethane (meth) acrylate by a compound having a (meth) acryloyl group and an isocyanate group. In the present invention, “(meth) acryloyl group” refers to an acryloyl group or methacryloyl group, and “(meth) acrylate” refers to acrylate or methacrylate.

  As an epoxy resin used by this invention, what is necessary is just a compound which has an epoxy group and a hydroxyl group in a molecule | numerator, and there is no restriction | limiting in particular in the structure. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolak type epoxy resin, p-tert-butylphenol novolak type epoxy resin, nonylphenol novolak And polyvalent epoxy resins such as t-butyl catechol type epoxy resins. Among these, it is preferable to use a bisphenol-type epoxy resin from the viewpoint of good curability and excellent corrosion resistance of the resulting cured coating film, and in particular, a general formula in which glycidylated bisphenol A and bisphenol A are condensed. An epoxy resin represented by (1 ′) is preferred.

（上記式（１’）中、ｎは１〜７の整数を表す。）

(In the above formula (1 ′), n represents an integer of 1 to 7)

  One example of the epoxy resin of the present invention is obtained by reacting a compound having a (meth) acryloyl group and an isocyanate group with the hydroxyl group in the general formula (1 ′), and is represented by the following general formula (1). It is what is done.

（上記一般式（１）中、Ｘは、置換基を有してもよい直鎖又は分岐のアルキレン基を表し、Ｒ^１は、水素原子又はメチル基を表す。また、ｎは、１〜７の整数を表す。）

(In the general formula (1), X represents a linear or branched alkylene group which may have a substituent, R ¹ represents a hydrogen atom or a methyl group, and n represents 1 to 7) Represents an integer.)

In addition, an epoxy resin represented by the following general formula (2) is reacted with a phenolic hydroxyl group of a novolak-type resin such as phenol novolak or cresol novolak by the epoxy resin represented by the following general formula (1 ′) After obtaining R ² in the formula (2) is the general formula (3 ′)), a hydroxyl group in the general formula (3 ′) is further reacted with a compound having a (meth) acryloyl group and an isocyanate group. Another example of the epoxy resin of the present invention is obtained by changing R ² in the following general formula (2) to general formula (3).

（上記一般式（２）中、Ｒ^３は、それぞれ独立して炭素原子数１〜８の直鎖又は分岐のアルキル基、又は水素原子を表す。また、ｍは、０〜３の整数を表す。）

(In the general formula (2), each R ³ independently represents a linear or branched alkyl group having 1 to 8 carbon atoms or a hydrogen atom. M represents an integer of 0 to 3. .)

（上記式（３’）中、ｐは１〜５の整数を表す。）

(In the above formula (3 ′), p represents an integer of 1 to 5.)

（上記一般式（３）中、Ｘは置換基を有してもよい直鎖又は分岐のアルキレン基を表し、Ｒ^４は水素原子又はメチル基を表す。また、ｐは１〜５の整数を表す。）

(In the above general formula (3), X represents a linear or branched alkylene group which may have a substituent, R ⁴ represents a hydrogen atom or a methyl group, and p represents an integer of 1 to 5. Represents.)

  X in the above general formula (1) or general formula (3) represents a linear or branched alkylene group which may have a substituent. For example, methylene group, ethylene group, propylene group, butylene Groups, the following formula (4), formula (5) and the like.

  Examples of the compound having the (meth) acryloyl group and the isocyanate group include 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 1,1-bis (acryloyloxymethyl) ethyl isocyanate, 1,1-bis (methacryloyloxy). And methyl) ethyl isocyanate, 2- (acryloylethoxy) -ethyl isocyanate, 2- (methacryloylethoxy) -ethyl isocyanate, and the like.

  The reaction conditions for urethane (meth) acrylate conversion of a hydroxyl group of an epoxy resin having a hydroxyl group with a compound having a (meth) acryloyl group and an isocyanate group are a reaction temperature of 40 to 100 ° C., and the peak of residual isocyanate is red. The reaction is preferably carried out until the external absorption spectrum (IR) is below the detection limit.

  The urethane (meth) acrylate can be reacted without a solvent, but as a solvent, benzene, toluene, xylene, ethyl acetate, acetone, methyl ethyl ketone, diethyl ether, tetrahydrofuran, methyl acetate, acetonitrile, chloroform, methylene chloride, four Carbon chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, tetrachloroethylene, N-methylpyrrolidone and the like may be used.

  Moreover, a urethanization catalyst can be used for urethane (meth) acrylate formation in this invention. Examples of the urethanization catalyst include amines such as triethylamine, triethylenediamine and N-methylmorpholine, metal salts such as potassium acetate, zinc stearate and tin octylate, and organometallic compounds such as dibutyltin dilaurate.

  The amine curing agent used in the present invention is not particularly limited. For example, aliphatic polyamines, heterocyclic polyamines, epoxy addition products thereof, Mannich modified products, and modified polyamide products may be used. it can. Examples thereof include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, metaxylenediamine, isophoronediamine, norbornenediamine, 1,3-bisaminomethylcyclohexane, N-aminoethylpiperazine and the like. These can be used alone or in combination of two or more.

  Among the above amine-based curing agents, Mannich modified products obtained by reacting phenols and formaldehyde are preferable from the viewpoint of excellent curability, and carboxylic acids such as dimer acid are reacted from the viewpoint of excellent anticorrosion performance of the cured products. The resulting polyamide is preferred.

  The compounding ratio between the epoxy resin as the main agent and the amine as the curing agent is preferably an equivalent ratio of epoxy group: active hydrogen in amine = 1: 0.5 to 1: 1.5, and particularly 1: 0. 8 to 1: 1.1 are preferred. In addition, the active hydrogen in an amine means the hydrogen atom couple | bonded with the nitrogen atom of an amine, and makes one hydrogen atom 1 equivalent.

  The epoxy resin composition of the present invention is not limited in any way except that the epoxy resin and the amine-based curing are used, and a curing accelerator is appropriately used in combination as long as the effects of the present invention are not impaired. It is also possible. Various curing accelerators can be used, and examples thereof include phosphorus compounds, tertiary amines, imidazoles, organic acid metal salts, Lewis acids, and amine complex salts.

  In order to impart coating suitability to the epoxy resin composition or anticorrosive paint of the present invention, a solvent may be blended. Examples of the solvent include alcohols such as isopropyl alcohol, isobutanol, and t-butyl alcohol, in addition to the solvent that can be used for the above urethane (meth) acrylate formation.

  Furthermore, the epoxy resin composition or anticorrosion paint of the present invention has a pigment, petroleum resin, film-forming aid, antifoaming agent, repellency prevention within the range that does not impair the effects of the present invention, depending on the purpose of use, properties, etc. An agent, a reactive diluent, a non-reactive diluent, an ultraviolet absorber, a light stabilizer and the like can be used in combination as appropriate.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
In the examples, “Example 1” is read as “Reference Example 1”, and “Example 3” is read as “Reference Example 3”.

(Example 1: Synthesis of epoxy resin of general formula (2))
In a four-necked flask equipped with a thermometer and a stirrer, an epoxy equivalent of 476 g / eq bisphenol A type epoxy resin (“Epiclon 1050” manufactured by DIC Corporation; an epoxy resin of the above general formula (1 ′), where n is an average 2.2) Charge 476 parts by mass and 231 parts by mass of xylene and dissolve them. 0.03 parts by mass of dibutyltin dilaurate (Neostan U-200 manufactured by Nitto Kasei Co., Ltd.) is added as a catalyst, and 36 parts by mass of 2-acryloyloxyethyl isocyanate (“Karenz AOI” manufactured by Showa Denko KK) is added for 1 hour at 50 degrees. Add in portions over a period of 2 hours after the addition. After confirming the disappearance of the isocyanate group (around 2250 cm ⁻¹ ) by IR, 0.05 part by mass of 2,6-di-t-butyl-4-methylphenol (hereinafter referred to as “BHT”) was added, and the nonvolatile content 70 mass% epoxy resin (A-1) was obtained.

(Example 2: Synthesis of epoxy resin of general formula (3))
Into a four-necked flask equipped with a thermometer, a stirrer, and a nitrogen gas inlet tube, an epoxy equivalent of 189 g / eq bisphenol A type epoxy resin (“Epiclon 850” manufactured by DIC Corporation; epoxy resin of the above general formula (1 ′)) Then, n is an average of 0.1) 189 parts by mass, 30 parts by mass of bisphenol A, and 23 parts by mass of phenol novolak (“M-70G” manufactured by DIC Corporation) having a hydroxyl group equivalent of 102 g / eq. The temperature is raised to 80 ° C., 0.04 part by mass of tetramethylammonium chloride is added, and the mixture is reacted at 140 ° C. for 5 hours. After confirming that the epoxy equivalent exceeded 470 g / eq, 296 parts by mass of bisphenol A type epoxy resin (“Epiclon 850” manufactured by DIC Corporation) and 101 parts by mass of xylene are added and cooled to 50 ° C. After adding 0.03 parts by mass of dibutyltin dilaurate (Neostan U-200 manufactured by Nitto Kasei Co., Ltd.) as a catalyst, 41 parts by mass of 2-acryloyloxyethyl isocyanate (“Karenz AOI” manufactured by Showa Denko KK) is taken over 1 hour. Add in portions, and react for another 2 hours after addition. After confirming disappearance of the isocyanate group (around 2250 cm ⁻¹ ) by IR, 0.05 part by mass of BHT and 43 parts by mass of isobutanol were added to obtain an epoxy resin (A-2) having a nonvolatile content of 80% by mass.

(Preparation Example 1)
In a four-necked flask equipped with a thermometer and a stirrer, 476 parts by mass of bisphenol A type epoxy resin (“Epiclon 1050” manufactured by DIC Corporation) having an epoxy equivalent of 476 g / eq and pentaerythritol triacrylate (“manufactured by Toagosei Co., Ltd.”) Aronix M-306 ") 24 parts by mass and 214 parts by mass of xylene were charged and dissolved to obtain a resin composition (A-3) of an epoxy resin having a nonvolatile content of 70% by mass and a polyfunctional acrylate.

(Preparation Example 2)
In a four-necked flask equipped with a thermometer, a stirrer, and a nitrogen gas inlet tube, 189 parts by mass of bisphenol A type epoxy resin (“Epiclon 850” manufactured by DIC Corporation) with an epoxy equivalent of 189 g / eq, 30 parts by mass of bisphenol A, and hydroxyl group 23 parts by mass of phenol novolak (“M-70G” manufactured by DIC Corporation) having an equivalent weight of 102 g / eq is charged. The temperature is raised to 80 ° C., 0.04 part by mass of tetramethylammonium chloride is added, and the mixture is reacted at 140 ° C. for 5 hours.
After confirming disappearance of the phenolic hydroxyl group, 296 parts by mass of bisphenol A type epoxy resin (“Epiclon 850” manufactured by DIC Corporation), 99 parts by mass of xylene and 42 parts by mass of isobutanol are added. Furthermore, by adding 27 parts by mass of pentaerythritol triacrylate (“Aronix M-306” manufactured by Toagosei Co., Ltd.) and stirring uniformly, a resin composition of an epoxy resin having a nonvolatile content of 80% by mass and a polyfunctional acrylate (A- 4) was obtained.

(Preparation Example 3)
In a four-necked flask equipped with a thermometer, a stirrer, and a nitrogen gas inlet tube, 189 parts by mass of bisphenol A type epoxy resin (“Epiclon 850” manufactured by DIC Corporation) with an epoxy equivalent of 189 g / eq, 30 parts by mass of bisphenol A, and hydroxyl group 23 parts by mass of phenol novolak (“M-70G” manufactured by DIC Corporation) having an equivalent weight of 102 g / eq is charged. The temperature is raised to 80 ° C., 0.04 part by mass of tetramethylammonium chloride is added, and the mixture is reacted at 140 ° C. for 5 hours.
After confirming the disappearance of the phenolic hydroxyl group, 296 parts by mass of a bisphenol A type epoxy resin (“Epiclon 850” manufactured by DIC Corporation), 99 parts by mass of xylene and 42 parts by mass of isobutanol were added to provide an epoxy having a nonvolatile content of 80% by mass. A resin composition (A-5) was obtained.

  Epoxy resins (A-1) and (A-2) obtained in Examples 1 and 2 above, resin compositions (A-3) to (A-5) and bisphenol obtained in Preparation Examples 1 to 3 Table 1 shows the property values of the A-type epoxy resin (“Epiclon 1050-70X” manufactured by DIC Corporation; xylene solution of “Epiclon 1050” having a resin content of 70 mass%).

(Preparation Example 4: Preparation of amine curing agent)
In a four-necked flask equipped with a thermometer, a stirrer, and a nitrogen gas introduction tube, 280 parts by mass of polyamidoamine (“TD-977” manufactured by DIC Corporation), Mannich polyamine (“F-4” manufactured by DIC Corporation) After charging 120 parts by mass and 38 parts by mass of 2,4,6-tris (dimethylaminomethyl) phenol (“Ancamine K-54” manufactured by Air Products Japan Co., Ltd.), the mixture was uniformly mixed at 50 ° C. An amine-based curing agent having 66.5% by mass and an active hydrogen equivalent of 200 g / eq (solution value) was obtained.

(Example 3)
100 parts by mass of the epoxy resin (A-1) obtained in Example 1 above (non-volatile content 70% by mass), 17 parts by mass of xylene, and 24.6 parts by mass of the amine curing agent obtained in Preparation Example 4 above. Were mixed uniformly to obtain an epoxy resin composition.

Example 4
100 parts by mass of the epoxy resin (A-2) obtained in Example 2 above (non-volatile content 80% by mass), 17 parts by mass of xylene, and 51.6 parts by mass of the amine curing agent obtained in Preparation Example 4 above. Were mixed uniformly to obtain an epoxy resin composition.

(Comparative Example 1)
100 parts by mass of the resin composition (A-3) (non-volatile content 70% by mass) obtained in Preparation Example 1 above, 17 parts by mass of xylene and 25.2 parts by mass of the amine-based curing agent obtained in Preparation Example 4 above. The parts were uniformly mixed to obtain an epoxy resin composition.

(Comparative Example 2)
100 parts by mass of the resin composition (A-4) obtained in Preparation Example 2 (non-volatile content: 80% by mass), 17 parts by mass of xylene, and 53.7 parts by mass of the amine-based curing agent obtained in Preparation Example 4 above. The parts were uniformly mixed to obtain an epoxy resin composition.

(Comparative Example 3)
100 parts by mass of the resin composition (A-5) obtained in Preparation Example 3 (non-volatile content: 80% by mass), 17 parts by mass of xylene, and 56.5 parts by mass of the amine curing agent obtained in Preparation Example 4 above. The parts were uniformly mixed to obtain an epoxy resin composition.

(Comparative Example 4)
Bisphenol A type epoxy resin (“Epiclon 1050-70X” manufactured by DIC Corporation, nonvolatile content 70% by mass) 100 parts by mass, xylene 17 parts by mass and amine-based curing agent 26.5 parts by mass obtained in Preparation Example 4 above Were mixed uniformly to obtain an epoxy resin composition.

(Low-temperature curability test)
The epoxy resin compositions obtained in Examples 3 and 4 and Comparative Examples 1 to 4 were applied to a glass plate (thickness 2.0 mm) using a gum tape weir so that the coating thickness after drying was 100 μm. Then, leave it in an atmosphere of 5 ° C and measure the semi-curing time and complete curing time (unit: hours) as low-temperature curing properties using a coating film curing rate tester (“RCI Driving Recorder” manufactured by Riken Engineering). did. The criteria for determining the half-curing time and the complete curing time are as follows.
Semi-curing time: The time until the scratch mark narrows rapidly.
Complete curing time: Time until scratches disappear.

(Water resistance test)
Using a bar coater, the dry film thickness is 50 μm on the cooled rolled steel sheet obtained by subjecting the epoxy resin compositions obtained in Examples 3 and 4 and Comparative Examples 1 to 4 to surface treatment with # 240 sandpaper. And then cured at 25 ° C. for 1 week to obtain a test piece for a water resistance test. The obtained test piece was immersed in water at 40 ° C. for 1 week, and the presence or absence of the occurrence of blister was visually confirmed.

(Anti-corrosion test)
An anticorrosion test was conducted using the test piece obtained in the same manner as the water resistance test. The anticorrosion test was performed according to JIS K-5600-7-1 (1999). After cross-cutting the test piece with a cutter, placing it in a tester and conducting a 300 hr test, visually confirming the occurrence of blisters in the flat part and measuring the swollen width of the coating film from the cross-cut part did. The unit of the swollen width is mm.

  Table 2 shows the compositions and test results of the epoxy resin compositions obtained in Examples 3 and 4 and Comparative Examples 1 to 4.

  From the results of Examples 3 and 4 shown in Table 2, it was found that the epoxy resin composition using the epoxy resin of the present invention was excellent in low-temperature curability and corrosion resistance.

  Comparative Examples 1 and 2 are examples using an epoxy resin and a tri- or higher functional acrylate compound, but there were no problems with water resistance and anticorrosion, but the low-temperature curability was somewhat insufficient.

  Comparative Examples 3 and 4 are examples in which an epoxy resin not urethane-acrylated was used, but there was no problem with water resistance and corrosion resistance, but it was found that the low-temperature curability was very low.

Claims (3)

An epoxy resin represented by the following general formula (2).

(In the general formula (2), each R ² independently represents the following general formula (3), and each R ³ independently represents a linear or branched alkyl group having 1 to 8 carbon atoms, or Represents a hydrogen atom, and m represents an integer of 0 to 3.)

(In the above general formula (3), X represents a linear or branched alkylene group which may have a substituent, R ⁴ represents a hydrogen atom or a methyl group, and p represents an integer of 1 to 5. Represents.) Epoxy resin composition characterized by containing an epoxy resin and an amine curing agent of claim 1 Symbol placement. An anticorrosion paint comprising the epoxy resin composition according to claim 2 .