JP4283642B2 - Epoxy paint composition - Google Patents

Description

  The present invention relates to a non-tar type epoxy coating composition, and more specifically, improves the wettability with a pigment, has excellent water resistance, overcoatability, and adhesion, and is particularly suitable for marine coating. It is about things.

Conventional tar-based epoxy paints have excellent corrosion resistance, water resistance, and chemical resistance, and are therefore used in a wide range of applications such as for ships and general structures.
However, since it contains tar, there is a concern that not only environmental safety problems are concerned, but since it is black, selection of coloration is difficult and the range of use is limited.

Therefore, a non-tar type epoxy paint using a petroleum hydrocarbon resin was developed, but since the petroleum hydrocarbon resin does not contain a polar group, the compatibility with the epoxy resin and the curing agent is inferior, and the cured product becomes cloudy. It is unsuitable as a paint.
In recent years, Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4 describe hydroxyl group-containing hydrocarbon resins obtained by polymerizing unsaturated fractions obtained by cracking petroleum in the presence of phenols in order to improve compatibility. Patent Document 5 and the like. Further, according to Patent Document 6, it was produced by polymerizing 60 to 90% of a high-purity indene fraction obtained by distillation of an aromatic fraction at 140 to 220 ° C. obtained by petroleum cracking in the presence of phenols. Examples using a hydroxyl group-containing hydrocarbon resin are also mentioned.
However, with the recent enhancement of paint functions, advanced performance such as wettability with pigments, corrosion resistance, water resistance, adhesiveness, and overcoatability has been required. However, these performance requirements have not been met.
JP 53-141361 JP 54-43259 A JP 54-46258 JP-A-61-203111 JP-A-9-263713 JP-A-11-323247

  The problem to be solved by the present invention is, as described above, an epoxy coating composition excellent in environmental safety, compatibility with epoxy resin, etc., and excellent in wettability with pigment, anticorrosion, overcoatability, etc. Is to provide.

As a result of intensive studies to solve the above problems, the present inventors have found that a modified hydrocarbon resin containing a hydroxyl group and a carboxyl group in the molecule is excellent in compatibility with an epoxy resin and a curing agent. .
As a result, the invention of an epoxy coating composition excellent in terms of wettability with pigments, anticorrosion, water resistance, and overcoating and adhesion of a coating film is completed without any environmental safety problems. It came to.

That is, the present invention is an epoxy coating composition containing an epoxy resin (A), a curing agent (B), and a modified hydrocarbon resin (C) having a hydroxyl group and a carboxyl group in the molecule, the modified hydrocarbon resin ( An epoxy coating composition in which the blending amount of C) is 10 to 500 parts by weight with respect to 100 parts by weight of the solid content of the epoxy resin (A) is provided.
Further, as a preferred embodiment of the present invention, the modified hydrocarbon resin (C) is (1) a monoolefin fraction containing an aromatic having a boiling point of 140 to 200 ° C. obtained by pyrolysis of petroleum in the first stage reaction. (C9 fraction) is mixed with a fraction containing an aliphatic conjugated double bond having a boiling point of 20 to 80 ° C. (C5 fraction) in a weight ratio of 1 to 50%, and further added with phenols, Friedel Kraft type Polymerization is carried out in the presence of a catalyst to obtain an unsaturated hydrocarbon resin containing unsaturated groups and hydroxyl groups (0.1 to 2.0) in the molecule. (2) In the second stage reaction, it can be produced by adding an organic unsaturated acid to the unsaturated group of the unsaturated hydrocarbon resin obtained by the first stage reaction by heating reaction, and the acid value is 2-50. The softening point is 40 to 150 ° C.

  Moreover, since the epoxy coating composition of the present invention is excellent in corrosion resistance, water resistance, etc., it can be used as a coating for ships and general structures.

  The modified hydrocarbon resin (C) having a hydroxyl group and a carboxyl group in the molecule is excellent in compatibility with an epoxy resin and a curing agent, and an epoxy coating composition containing the modified hydrocarbon resin is excellent in workability during application and water resistance. The effect which was excellent also in the property, corrosion resistance, and adhesiveness is seen. Moreover, since tar is not contained at all, there is no environmental problem and a light-colored coating film can be formed. Therefore, it is useful mainly as an anticorrosion paint for ships and general structures.

  Various performances of the epoxy coating composition according to the present invention can be obtained by using a modified hydrocarbon resin (C) having both a hydroxyl group and a carboxyl group in the molecule. This is considered to be due to the presence of an appropriate ratio to improve the compatibility with the epoxy resin and the curing agent. In particular, when the number of hydroxyl groups is large, the hydrophilicity increases, which adversely affects the water resistance and anticorrosion properties of the paint, and further leads to a decrease in adhesion. Therefore, by introducing an appropriate amount of carboxyl group, it is possible to balance hydrophilicity and hydrophobicity, and as a result, it seems to improve water resistance, corrosion resistance, adhesion, and pigment wettability.

The present invention will be described in detail below.
The epoxy resin (A) described in the present invention has at least two epoxy groups per molecule, and those having an epoxy equivalent of 150 to 600 are suitable, more preferably 180 to 500. Examples of such resins include bisphenol A type epoxy resins, aliphatic type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, cresol type epoxy resins, dimer acid-modified epoxy resins, and the like. Conventionally known ones can be mentioned, and these can be used alone or in combination of two or more.

  Examples of phenols used as a raw material for polymerization of the present invention include monovalent phenols such as phenol, o-cresol, m-cresol, p-cresol, butylphenol and xylenol, and alkyl-substituted phenols such as nonylphenol and dinonylphenol. be able to. Moreover, these can also be mixed and used.

As the curing agent (B) used in the present invention, a known curing agent for epoxy resins can be used. Examples include various aliphatic or aromatic amines, polyamide resins, acid anhydrides, phenol resins, polyisocyanates, and the like. These can be used alone or in combination.
Particularly preferred are amine-based curing agents such as metaxylenediamine, isophoronediamine, diethylenetriamine, triethylenetetraamine, diaminodiphenylmethane and other aliphatic polyamines, aromatic polyamines, epoxy resin adducts of these polyamines, polyamides Examples include amines and polyamide resins. These can be used alone or in combination of two or more.

  The proportions of the epoxy resin (A) and the curing agent (B) can be appropriately selected depending on the types of both components. Generally, it can be selected from the range of 10 to 500 parts by weight of the curing agent per 100 parts by weight of the epoxy resin. When using a preferable amine-based curing agent as the curing agent (B), the equivalent ratio usually expressed by (active hydrogen equivalent of (B)) / (epoxy equivalent in (A)) is 0.5 to 1.0. It is appropriate to select the range.

In the modified hydrocarbon resin (C) in the present invention, phenols are first mixed in advance with the C9 fraction obtained by petroleum cracking in the first stage reaction, and the C5 fraction containing a conjugated double bond is further mixed by weight ratio. It is a hydroxyl group-containing unsaturated hydrocarbon resin having an unsaturated group in the molecule, which can be obtained by polymerizing the mixture in the range of 1 to 50% under a Friedel-Craft type catalyst.
Next, in the second stage reaction, the unsaturated group of the hydroxyl group-containing unsaturated hydrocarbon resin obtained by the first stage reaction is heated and reacted with an organic unsaturated acid in a conventional manner, and the acid value is in the range of 2-50. A carboxyl group is introduced so that a modified hydrocarbon resin (C) containing a hydroxyl group and a carboxyl group having a softening point of 40 to 150 ° C. is obtained.

  Here, for example, a polymer obtained by polymerizing only the C9 fraction does not have an unsaturated bond in the molecule sufficient for proceeding with the second stage reaction, so that it is difficult to introduce a carboxyl group by addition of an organic unsaturated acid. I can say that.

  Examples of the addition of the organic unsaturated acid include a method of heating an organic unsaturated acid in addition to α / β unsaturated acids such as maleic anhydride and fumaric acid, and adding in a conventional manner.

  The reaction components used as raw materials for the modified hydrocarbon resin (C) will be described in more detail. When ethylene and propylene are produced by pyrolysis of petroleum, the C9 fraction obtained as a by-product contains styrene, Mono-olefins such as α and β methylstyrene, vinyltoluene, indene and methylindene are included. The reaction component of the C5 fraction contains a conjugated double bond monomer such as isoprene, piperylene, or cyclopentadiene.

  The modified hydrocarbon resin (C) used in the epoxy coating composition of the present invention contains 0.1 to 2.0, preferably 0.2 to 1.0, phenolic hydroxyl groups in one molecule. This can be appropriately adjusted depending on the amount of each raw material charged, the polymerization conditions, and the like. If there are more than 2.0 phenolic hydroxyl groups, the hydrophilicity increases, and the water resistance and anticorrosion properties as an anticorrosion paint are inferior, which is not preferable. On the other hand, when the number is less than 0.1, compatibility with a curing agent such as an epoxy resin and amines is lowered, which is also not preferable. The modified hydrocarbon resin (C) has an acid value of 2-50. When the acid value is less than 2, it is not preferable in terms of wettability and adhesion of the pigment of the paint, and when the acid value exceeds 50, it is not preferable in terms of water resistance and corrosion resistance. In order for the modified hydrocarbon resin (C) to bring out the characteristics of the paint most, it is preferable that the molecule has 0.1 to 2.0 hydroxyl groups and the acid value is in the range of 2 to 50.

  Further, when the softening point of the modified hydrocarbon resin (C) is less than 40 ° C., the resin may bleed on the surface of the coating film and stickiness may remain. On the other hand, when the temperature exceeds 150 ° C., the viscosity of the paint is high, and the physical properties of the coating film are deteriorated. In addition, the range of the preferable number average molecular weight of the modified hydrocarbon resin (C) by this invention is 400-2500.

  In order to obtain the epoxy coating composition of the present invention, 10 to 500 parts by weight of the modified hydrocarbon resin (C) is blended with 100 parts by weight of the epoxy resin (A). When the blending amount is less than 10 parts by weight, the resulting coating film has a high hardness and inferior impact resistance. On the other hand, when the amount exceeds 500 parts by weight, the softness of the coating film increases, but the water resistance is inferior.

  For the purpose of imparting flexibility to the epoxy coating composition of the present invention, a liquid modifier, for example, a reactive resin such as xylene resin, toluene resin, butyl glycidyl ether, etc., is added to 100 parts by weight of the epoxy resin. On the other hand, these additives, which may be added in the range of 50 parts by weight or less, are preferably aromatic ones from the viewpoint of maintaining water resistance.

  If necessary, the epoxy coating composition of the present invention further includes extenders, pigments such as color pigments, reactive diluents, organic solvents, anti-settling agents, sagging inhibitors, wetting agents, reaction accelerators, and adhesion. Ordinary paint additives such as a property-imparting agent and a dehydrating agent may be appropriately blended.

The composition of the present invention is a two-component paint comprising an epoxy resin-containing main agent and a curing agent, preferably an amine curing agent, and is usually applied to a rust-preventing coating such as a zinc primer. That is, first, shot blasting is applied to the steel plate to remove the mill scale, and an inorganic zinc shop primer such as ethyl silicate is applied, and then the coating composition of the present invention is applied. Primers are not limited to zinc silicate and the like, and various primers can be used.
Further, even a steel plate without a primer can be painted, and a sufficient anticorrosive effect can be obtained. As a coating method, conventionally known methods such as air spray, airless spray, brush coating, and roller can be adopted, and the coating composition can be applied to a dry film thickness of 150 to 500 μm.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited by these Examples.
Parts and% indicate parts by weight and% by weight, respectively.

Example 1
1) Production of Modified Hydrocarbon Resin (C) First, in the first stage reaction, 100 parts of an aromatic C9 fraction (containing 55% monoolefin) having a boiling point of 140 to 200 ° C. obtained by pyrolysis of petroleum had a boiling point of 20 Add 5 parts of aliphatic C5 fraction (containing 30% conjugated double bond) at -80 ° C., and further add 8 parts of phenol and keep the reaction temperature at 20 ° C. 0.0 part was added dropwise over 1 hour. Thereafter, the reaction was terminated by aging for 4 hours at the same temperature. Thereafter, the catalyst was decomposed with a caustic soda solution, washed with water, and then unreacted oil and low polymer were removed by distillation under reduced pressure to obtain 60 parts of a hydroxyl group-containing unsaturated hydrocarbon resin containing 0.6 hydroxyl groups in the molecule. .
Next, as the second-stage reaction, 0.4 part of maleic anhydride is added to 40 parts of the resin obtained in the first-stage reaction and reacted at 200 ° C. for 3 hours. Maleic anhydride was removed. The acid value of this resin was 6, and a modified hydrocarbon resin (C) containing a hydroxyl group and a carboxyl group in the molecule was obtained. The resulting modified hydrocarbon resin (C) had a softening point of 98 ° C.
The properties of the obtained resin are shown in Table 1.
2) Preparation of paint 100 parts of epoxy resin, 50 parts of titanium white, 100 parts of talc, 120 parts of modified hydrocarbon resin (C), 5 parts of sagging stopper and 15 parts of plasticizer, mixed solvent (MIBK / xylene; 25/25 ) 50 parts was added and mixed uniformly with a stirrer to obtain the main agent. As a curing agent, 80 parts of polyamide resin (in terms of solid) was added thereto, and mixed and stirred to obtain an epoxy coating composition. The compositions and paint evaluation results are shown in Tables 2 and 3.

Examples 2 and 3
A modified hydrocarbon resin (C) was produced under the same conditions as in Example 1 according to the formulation shown in Table 1. The properties are shown in Table 1.
The paint was made in the same manner as shown in Example 1. Tables 2 and 3 show the compositions and paint evaluation results.

Comparative production example 1
1) Production of resin The first stage reaction was carried out under the same conditions as in Example 1, except that 100 parts of C9 fraction (without prescribing C5 fraction) was polymerized in the presence of 8 parts of phenol, and contained hydroxyl groups. A hydrocarbon resin was obtained. The addition reaction of maleic anhydride by the next second stage reaction was not performed. The properties of the obtained resin are shown in Table 1.
2) Coating The coating was made by the same method as shown in Example 1. Tables 2 and 3 show the compositions and paint evaluation results.

Comparative production example 2
1) Production of resin Hydrocarbons containing no hydroxyl group were carried out under the same conditions as in Example 1 except that the first stage reaction was polymerized only with 100 parts of C9 fraction (C5 fraction, in the absence of phenol). A resin was obtained.
In the next second stage reaction, 0.4 part of maleic anhydride was added to 40 parts of this resin, and an addition reaction of maleic anhydride was attempted in the same manner as in Example 1. However, unlike Example 1, the acid value of the obtained resin was as low as 1.6. This is presumably because the resin obtained in the first-stage reaction does not have an unsaturated bond sufficient to advance the addition reaction, and therefore the reactivity is inferior.
The properties of the obtained resin are shown in Table 1.
2) Coating The coating was made by the same method as shown in Example 1. Tables 2 and 3 show the compositions and paint evaluation results.

Comparative production example 3
1) Production of Resin 0.4 parts of maleic anhydride was added to 40 parts of the hydroxyl group-containing hydrocarbon resin obtained in Comparative Example 1 and a second-stage reaction was attempted. Similar to Comparative Example 2, the reactivity was poor. The acid value of the obtained resin was as low as 1.7.
The properties of the obtained resin are shown in Table 1.
2) Coating The coating was made by the same method as shown in Example 1. The compositions and paint evaluation results are shown in Tables 2 and 3.

  As shown in Examples 1 to 3 in Table 3, it can be seen that the epoxy coating composition of the present invention is excellent in durability, corrosion resistance, workability during application, and the like. Moreover, since tar is not contained at all, there is no environmental problem and a light-colored coating film can be formed. Therefore, it is useful as an anticorrosion paint for ships and general structures.

Claims (2)

Epoxy resin (A), curing agent (B), and
(1) In the first-stage reaction, a monoolefin fraction (C9 fraction) containing an aromatic having a boiling point of 140 to 200 ° C. obtained by pyrolysis of petroleum is added to an aliphatic conjugate 2 having a boiling point of 20 to 80 ° C. A fraction containing a heavy bond (C5 fraction) is mixed in a weight ratio of 1 to 50%, further phenols are added, and polymerization is carried out in the presence of a Friedel-Craft type catalyst. An unsaturated hydrocarbon resin containing (0.1 to 2.0) is obtained.
(2) In the second stage reaction, it can be produced by adding an organic unsaturated acid to the unsaturated group of the unsaturated hydrocarbon resin obtained in the first stage reaction by a heating reaction,
An epoxy coating composition containing a modified hydrocarbon resin (C) having a hydroxyl group and a carboxyl group in the molecule, having an acid value of 2 to 50 and a softening point of 40 to 150 ° C., wherein the modified hydrocarbon resin The epoxy coating composition whose compounding quantity of (C) is 10-500 weight part with respect to 100 weight part of epoxy resin (A) solid content. A marine paint containing the epoxy paint composition according to claim 1 .