JP6873934B2 - Paint composition - Google Patents

Description

The present invention relates to a coating composition for forming an insulating coating film on an electric wire support or an electric wire body.

Conventionally, when a bird nests on the arm of a transmission tower or a distribution tower, the nesting material touches an electric wire, which may cause a ground fault. In order to prevent such a ground fault, a technique has been proposed in which the arm portion of the transmission tower and the metal fittings connecting the insulators are coated with an insulating coating film (see, for example, Patent Document 1). Here, in Patent Document 1, a soft-modified resin such as a soft-modified epoxy resin, a soft-modified urethane, or a soft-modified polyester is used as a coating composition.

Japanese Unexamined Patent Publication No. 6-325649

However, when the conventional coating composition is applied to the electric wire support or the electric wire body, it is difficult to obtain the thickness of the coating film. As a result, there is a problem that it is difficult to secure the insulating property of the coating film.

An object of the present invention is to provide a coating composition capable of forming a coating film having sufficient insulating properties and having good coating properties.

The present invention is a coating composition for forming an insulating coating film on an electric wire support or an electric wire main body, and includes a resin composition (A), a curing agent (B), and an extender pigment (C). , The resin composition (A) contains a castor oil-based polyol (a-1), the curing agent (B) is a polyisocyanate, and the extender pigment (C) is from mica, sericite and silica. It relates to a coating composition containing at least one selected from the above group and having a pigment volume concentration (PVC) in the coating composition of 15 to 20%.

The resin composition (A) further contains a bisphenol A propylene oxide adduct (a-2), and the solid content of the bisphenol A propylene oxide adduct (a-2) is the total solid content of the coating composition. It is preferably 7 parts by mass or less with respect to 100 parts by mass.

The solid content of the bisphenol A propylene oxide adduct (a-2) is preferably 1 part by mass or less with respect to 100 parts by mass of the total solid content of the coating composition.

According to the present invention, it is possible to form a coating film having sufficient insulating properties and to provide a coating composition having good coating properties.

Hereinafter, the coating composition according to the present invention will be specifically described.

[Paint composition]
The coating composition according to the present invention contains a resin composition (A), a curing agent (B), and an extender pigment (C). The pigment volume concentration (PVC) in the coating composition is 15 to 20%.

<Resin composition (A)>
The resin composition (A) contains a castor oil-based polyol (a-1). Further, the resin composition (A) according to the present embodiment further contains, for example, a bisphenol A propylene oxide adduct (a-2).

Examples of the castor oil-based polyol (a-1) include castor oil and castor oil derivatives. Castor oil derivatives include, for example, castor oil fatty acid, hydrogenated castor oil, ester exchange of castor oil with fats and oils other than castor oil, reaction product of castor oil with polyhydric alcohol, castor oil fatty acid and polyhydric alcohol. Examples thereof include esterification reactions of the above, and addition polymerization of alkylene oxide to these.

When the resin composition (A) contains the bisphenol A propylene oxide adduct (a-2), a coating film having high strength can be obtained. The solid content of the bisphenol A propylene oxide adduct (a-2) according to the present embodiment is, for example, 7 parts by mass or less, preferably 1 part by mass, based on 100 parts by mass of the total solid content of the coating composition. It is less than a part by mass. Even if the solid content of the bisphenol A propylene oxide adduct (a-2) is 7 parts by mass or less, a coating film having sufficiently high strength can be obtained.

The resin composition (A) may contain additives other than castor oil-based polyol (a-1) and bisphenol A propylene oxide adduct (a-2). As additives, for example, wetting agent, wetting dispersant, defoaming agent, defoaming agent, surface conditioner, sedimentation inhibitor, thixotropic additive, rheology control agent, rocking agent, rocking modification modifier, viscosity adjustment Agents, thickeners and the like can be mentioned.

<Curing agent (B)>
The curing agent (B) is a polyisocyanate. As used herein, polyisocyanate refers to a compound having two or more isocyanate groups in one molecule. Examples of the polyisocyanate include aromatic diisocyanates, aliphatic diisocyanates having 3 to 12 carbon atoms, alicyclic diisocyanates having 5 to 18 carbon atoms, aliphatic diisocyanates having an aromatic ring, and modified products of these diisocyanates (urethane products, etc.). Carbodiimide, uretdione, uretoimine, burette and / or isocyanurate modified product) and the like.

Examples of the aromatic diisocyanate include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), p-phenylenediocyanate, and naphthalene diisocyanate. Examples of the aliphatic diisocyanate having 3 to 12 carbon atoms include hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexane diisocyanate, and lysine diisocyanate. Examples of the alicyclic diisocyanate having 5 to 18 carbon atoms include 1,4-cyclohexane diisocyanate (CDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), methylcyclohexane diisocyanate, and isopropi. Redendicyclohexyl-4,4'-diisocyanate, and 1,3-diisocyanatomethylcyclohexane (hydrogenated XDI), hydrogenated TDI, 2,5- or 2,6-bis (isocyanatomethyl) -bicyclo <2. 2.1> Heptane (also referred to as norbornandiisocyanate) and the like. Examples of the aliphatic diisocyanate having an aromatic ring include xylene diisocyanate (XDI) and tetramethylxylene diisocyanate (TMXDI). These can be used alone or in combination of two or more.

<Constituent pigment (C)>
The extender pigment (C) contains at least one selected from the group consisting of mica, sericite and silica. When the coating composition contains the extender pigment (C), it becomes easy to secure the film thickness of the coating film, and the coatability is improved. Further, in general, mica, sericite and silica have high insulating properties themselves, and therefore, when the coating composition contains these extender pigments (C), the insulating properties of the coating film become higher. The extender pigment (C) may further contain, for example, calcium carbonate, precipitated barium sulfate, kaolin and the like, and may be two or more of mica, sericite and silica.

In addition, in this specification, a pigment (for example, silica) which may be generally classified into an extender pigment (C) and a color pigment is classified into an extender pigment (C).

<Pigment Volume Concentration (PVC)>
The pigment volume concentration (PVC) in the coating composition containing the resin composition (A), the curing agent (B), and the extender pigment (C) is 15 to 20%. When the pigment volume concentration (PVC) is 15 to 20%, a coating composition having good coatability can be obtained. Further, if the pigment volume concentration (PVC) is less than 15%, the insulating property of the coating film becomes insufficient.

The pigment volume concentration (PVC) of the coating composition according to the present embodiment is the formula P / (P + R) × 100 from the volume (P) of the extender pigment (C) and the total volume (R) of all the resins. It is a value calculated from.

<Coloring pigment>
The coating composition according to the present embodiment preferably does not contain a coloring pigment such as carbon black or iron oxide. In general, carbon black, iron oxide and the like are pigments having high conductivity themselves, and therefore, when the coating composition does not contain these coloring pigments, the insulating property of the coating film is improved. Examples of the coloring pigment other than carbon black and iron oxide include titanium oxide.

As described above, the coating composition according to the present embodiment containing the resin composition (A), the curing agent (B), and the extender pigment (C) is a so-called two-component mixed type in which the main agent and the curing agent are used. It is a coating composition of. As a method for preparing these main agent and curing agent, a method usually used by those skilled in the art can be used without requiring a special method.
For example, as a method for preparing the main agent, a resin vehicle component, that is, a resin composition (A) is added with an extender pigment (C) and, if necessary, other components such as the above additives, and a disper, a twin-screw disper, and a ball mill are added. , S. G. Examples thereof include a method of preparing by dispersing with a disperser such as a mill, a roll mill, or a planetary mixer.
Further, as a method of mixing the main agent and the curing agent, a method usually used by those skilled in the art, for example, a method using a disper, a handheld mixer, a tip collision mixing spray gun, or the like can be used without requiring a special method. it can.

[Painting method]
The coating composition according to this embodiment is used to form an insulating coating film on an electric wire support or an electric wire main body. Examples of the painting method include the following methods.

First, the painted portion of the electric wire support (for example, the arm portion of the transmission tower or the distribution tower) is cleaned with a wire brush or the like to make it clean. Then, the coating composition is coated with a trowel or the like so that the dry film thickness (thickness of the insulating coating film) of the coating composition is, for example, 1.5 mm or more. The coating composition coated on the electric wire support is cured in about 30 minutes to form an insulating coating film. In this way, the coating composition can be used to form an insulating coating on the wire support. An insulating coating film can be formed on the wire body in the same manner.

[Insulation]
The insulating property of the insulating coating film according to the present embodiment will be described.
Electricity is normally transmitted by three charged wires. When the voltage class is 77 kV, the voltage difference between the charged wires is 77 kV, and the voltage difference with respect to the ground is 77 kV divided by the square root of 3 (44.5 kV). That is, assuming that it is applied to a wire support having a voltage class of 77 kV or less or a wire body, if the dielectric breakdown resistance value of the insulating coating film is 45 kV or more, dielectric breakdown does not occur.

As described above, the coating composition according to the present embodiment is a coating composition for forming an insulating coating film on an electric wire support or an electric wire main body, and is a resin composition (A) and a curing agent (B). The resin composition (A) contains a castor oil-based polyol (a-1), the curing agent (B) is a polyisocyanate, and the pigment volume in the coating composition. The concentration (PVC) is 15-20%. Thereby, a coating film having sufficient insulating properties can be formed, and a coating composition having good coating properties can be provided.
In addition, the extender pigment (C) contains at least one selected from the group consisting of mica, sericite and silica. As a result, a coating film having higher insulating properties can be formed.

Further, the resin composition (A) further contains a bisphenol A propylene oxide adduct (a-2), and the solid content of the bisphenol A propylene oxide adduct (a-2) is the total solid content of the coating composition. It is 7 parts by mass or less with respect to 100 parts by mass. As a result, the paintability of the coating composition becomes better.

The solid content of the bisphenol A propylene oxide adduct (a-2) is 1 part by mass or less with respect to 100 parts by mass of the total solid content of the coating composition. As a result, a coating film having higher insulating properties can be formed.

The present invention is not limited to the above embodiment, and modifications and improvements within the range in which the object of the present invention can be achieved are included in the present invention.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples.

<Example 1>
A resin composition (A) consisting of 37 parts by mass of castor oil polyol (a-1) and 4 parts by mass of bisphenol A propylene oxide adduct (a-2) and 25 parts by mass of diphenylmethane diisocyanate, respectively, in terms of solid content. A curing agent (B) made of (MDI), an extender pigment (C) made of 19 parts by mass of mica and 11 parts by mass of silica, and 4 parts by mass of additives (dehydrating agent, dispersant) are mixed. The coating composition of Example 1 was obtained. The pigment volume concentration (PVC) of the coating composition of Example 1 was 15%. Further, the coating composition of Example 1 was coated on a base material by brush coating and iron coating with a target dry film thickness of 1.5 mm or more, and dried to obtain a coating film of Example 1.

<Examples 2 to 6>
The resin composition (A), the curing agent (B), and the extender pigment (C) are mixed at the mass ratio in terms of solid content shown in Table 1, and the coating compositions of Examples 2 to 6 are prepared. Obtained. The pigment volume concentration (PVC) of these coating compositions was the value shown in Table 1. Further, by brush coating and iron coating, the target dry film thickness is set to 1.5 mm or more, the coating composition of Examples 2 to 6 is applied to the base material, and the substrate is dried to dry the coating compositions of Examples 2 to 6. A coating film was obtained.

<Comparative Examples 1 to 7>
The resin composition (A), the curing agent (B), and the extender pigment (C) are mixed at the mass ratio in terms of solid content shown in Table 1, and the coating compositions of Comparative Examples 1 to 7 are prepared. Obtained. The pigment volume concentration (PVC) of these coating compositions was the value shown in Table 1. Further, by brush coating and iron coating, the target dry film thickness is set to 1.5 mm or more, the coating compositions of Comparative Examples 1 to 7 are coated on the base material, dried, and compared with Comparative Example 1 and Comparative Example 2. A coating film was obtained.

[Resin composition (A)]
As the resin composition (A) of each Example and Comparative Example, the following commercially available products were used.
-Castor oil polyol (a-1): polyol (trade name) (solid content 99% or more), manufactured by Ito Oil Co., Ltd.-Bisphenol A propylene oxide adduct (a-2): Nieuport BP-2P (trade name) ( Solid content 99% or more), manufactured by Sanyo Kasei Kogyo Co., Ltd.

[Curing agent (B)]
The following commercially available products were used as the curing agent (B) of each Example and Comparative Example.
-MDI (diphenylmethane diisocyanate): Millionate MR-200 (trade name) (solid content 99% or more) manufactured by Nippon Polyurethane Industry Co., Ltd.

[Constitution pigment (C)]
The following commercially available products were used as the extender pigments (C) of each Example and Comparative Example.
-Mica: Micromica C-1000 (trade name) (specific gravity: 2.8), manufactured by Shiraishi Calcium Co., Ltd.-Calcium carbonate: Super # 1700 (trade name) (product name: 2.7), manufactured by Maruo Calcium Co., Ltd.-Silica: Crystallite 5X (trade name) (specific gravity: 2.6), Ryumori Co., Ltd.-precipitating barium sulfate: Precipitating barium sulfate 100 (trade name) (product name: 4.5), Sakai Chemical Industry Co., Ltd., kaolin: ASP-600 (trade name) (specific gravity: 2.6), manufactured by BASF

[Paint properties and paint properties]
The coating properties and coating properties when the coating compositions of the Examples and Comparative Examples were applied to the base material by brush coating and iron coating were evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.
(Evaluation criteria)
1: The viscosity is low or high enough to hinder the coatability, or the dry film thickness can be applied less than 1.5 mm at a time.
2: There is no problem in paintability, and the dry film thickness can be applied at a time of 1.5 mm or more.

[Insulation]
Dielectric strength tests in oil were performed on the coating films of each Example and Comparative Example. The dielectric breakdown resistance values of the coating films of each example and comparative example were measured.

From the comparison between Examples 1 to 6 and Comparative Examples 1 and 3 to 7, when the pigment volume concentration (PVC) of the coating composition is less than 15%, the insulating property of the coating film becomes low. (The dielectric breakdown value was less than 45 kV), and it was confirmed that the coatability also deteriorated. From the comparison between Examples 1 to 6 and Comparative Example 2, it was confirmed that when the pigment volume concentration (PVC) of the coating composition exceeds 20%, the coatability deteriorates. Therefore, it was confirmed that when the pigment volume concentration (PVC) in the coating composition is 15 to 20%, a coating film having sufficient insulating properties can be formed and the coating property of the coating composition is improved.

Further, by comparing Example 1 and Example 3 to Example 7, even if the pigment volume concentration (PVC) of the coating composition is about the same, the more mica is contained in the extender pigment (C), the more the coating is applied. It was confirmed that the insulating property of the film tended to be higher. It is clear that mica and sericite are silicate minerals and show the same tendency even if mica and sericite are replaced.
Therefore, it was confirmed that the extender pigment (C) can form a coating film having higher insulating properties by being at least one of mica, sericite and silica (particularly by containing a large amount of mica and sericite). ..

Further, although there was no difference in the coating properties and the evaluation results of the coating properties of each example, the higher the content of the bisphenol A propylene oxide adduct (a-2), the higher the strength of the coating film tended to be. confirmed.
On the other hand, although there was no difference in the paint properties and the evaluation results of the paint properties of each example, the larger the content of the bisphenol A propylene oxide adduct (a-2), the harder the paint, and the harder the paint, the more brushed and ironed. It was confirmed that it became difficult to stretch.
From the above, by comparing each example, it is possible to obtain a coating film having sufficiently high strength even if the solid content of the bisphenol A propylene oxide adduct (a-2) is 7 parts by mass or less. it was thought. On the contrary, when the solid content of the bisphenol A propylene oxide adduct (a-2) exceeds 7 parts by mass, it is considered that it is not realistic because the strength of the coating film is excessively increased and the coatability is deteriorated. Was done.

In particular, it was confirmed that when the solid content of the bisphenol A propylene oxide adduct (a-2) is 4 parts by mass or less (Examples 1 to 5), a coating film having higher insulating properties can be formed. It was.
Further, it was confirmed that when the solid content of the bisphenol A propylene oxide adduct (a-2) is 1 part by mass or less (Examples 4 and 5), a coating film having higher insulating properties can be formed. It was.

Claims (2)

A coating composition for forming an insulating coating film on an electric wire support or an electric wire body.
The resin composition (A), the curing agent (B), and the extender pigment (C) are contained.
The resin composition (A) contains a castor oil-based polyol (a-1).
The resin composition (A) further contains a bisphenol A propylene oxide adduct (a-2).
The solid content of the bisphenol A propylene oxide adduct (a-2) is 7 parts by mass or less with respect to 100 parts by mass of the total solid content of the coating composition.
The curing agent (B) is a polyisocyanate, and the curing agent (B) is a polyisocyanate.
The extender pigment (C) contains at least one selected from the group consisting of mica, sericite and silica.
A coating composition in which the pigment volume concentration (PVC) of the extender pigment (C) in the coating composition is 15 to 20%. The coating composition according to claim 1 , wherein the solid content of the bisphenol A propylene oxide adduct (a-2) is 1 part by mass or less with respect to 100 parts by mass of the total solid content of the coating composition.