KR20160089107A - thermosetting bisphenol F type epoxy powder coating composition - Google Patents

Abstract

The present invention relates to a thermosetting bisphenol F-type epoxy coating powder composition, and more specifically, to a composition having high bonding ability to a target object, impact resistance, cathodic disbonding ability, chemical resistant properties, and that produces no detectable environmentally hazardous material in an elution test of a paint film. Owing to these characteristics, the present composition can be applied to water pipes for drinking water. The thermosetting bisphenol F-type epoxy coating powder composition comprises: 100 parts by weight of a bisphenol F-type epoxy resin having an epoxy equivalent weight of 500-2200 g/eq; 5-70 parts by weight of a bisphenol F-type epoxy curing agent having an epoxy equivalent weight of 50-800 g/eq; 0.1-15 parts by weight of a curing accelerator; 5-90 parts by weight of an inorganic filler; and 5-80 parts by weight of a color pigment.

Description

[0001] The present invention relates to thermosetting bisphenol F type epoxy powder coating composition,

The present invention relates to a thermosetting bisphenol F type epoxy powder coating composition, and more particularly to a thermosetting bisphenol F type epoxy powder coating composition which is excellent in adhesion with a conductor and excellent in impact resistance, peeling resistance and chemical resistance, The present invention also relates to a composition having an advantage that an environmentally harmful component is not detected at all in the dissolution test.

With the above characteristics, the composition of the present invention is also applicable to a conductor to be used for a drinking water pipe.

"Powder coating" is a 100% solid coating that does not contain a diluent such as a solvent. When coated on a conductor (mainly a metal surface), it is dissolved by heating to form a coating film to form a coating film. This is the most important feature. In addition, it is one of the paints that have recently been recognized as a part of global energy conservation and resource measures as pollution-free paints.

Powder coatings can be largely classified into thermosetting and thermoplastic depending on the polymer before use, but thermosetting powder coatings are mainly used at present.

The thermosetting powder coating material is superior in physical properties of a coating film to a coating film suitable for finishing finishing, and has a high molecular weight by crosslinking with a curing agent using a low molecular weight thermosetting resin. Examples of thermosetting powder coatings include epoxy powder coatings, polyester powder coatings, epoxy polyester powder coatings, polyurethane powder coatings, and acrylic powder coatings.

The thermoplastic powder coating is made of polyethylene, polyvinyl chloride and polyamide powder coating, and the resin is melted in the sintering process to form a smooth coating film surface. These thermoplastic powder coatings are excellent in water resistance, but have a disadvantage in that the degree of adhesion is low and the heating temperature is narrow.

Currently, Ductal cast iron pipes, steel pipes and fittings are corrosion protection and protective coatings, and liquid epoxy bitumen and bisphenol A (BPA) epoxy powder coatings have already been developed and widely applied. The bisphenol A type epoxy powder coating has excellent mechanical properties in terms of corrosion resistance and adhesion to a conductor.

The resin used for bisphenol A type epoxy powder coating is an epoxy resin which is most widely used commercially so far, and the condensation between diphenylpropane (DPP), which is known as bisphenol A, and epichlorohydrin (ECH) Is a diglycidyl ether type epoxy resin produced by a reaction.

However, the bisphenol A is a kind of environmental hormone (endocrine disruptor), and is a substance that constantly raises environmental and human controversy. Bisphenol A is one of the 67 types of endocrine disrupting substances specified by the World Health Organization and is a sex hormone-like substance such as dioxin. When the human body comes into contact with bisphenol A, the human body believes that bisphenol A is a real sex hormone, A, which causes endocrine disruption and sudden displacement.

Accordingly, there is a need for an alternative epoxy resin composition that can be preferably used as a powder coating instead of a bisphenol A type resin.

It is an object of the present invention to provide a resin composition which can replace a bisphenol A type resin and which is excellent in adhesion to a conductor when used, excellent in impact resistance, peeling resistance in an anode and chemical resistance, And has the advantage that no component is detected at all.

Thus, it is intended to provide a powder coating composition which can be applied to a conductor to be used for drinking water pipes.

In order to solve the above problems, the present invention relates to a thermosetting bisphenol F type epoxy powder coating composition which can be used for a drinking water pipe by using a bisphenol F type epoxy resin which has a physical property equal to or higher than that of bisphenol A and does not discharge harmful substances to human body .

The thermosetting bisphenol F type epoxy powder coating composition according to the present invention is a thermosetting bisphenol F-

5 to 70 parts by weight of a bisphenol F type epoxy curing agent having an epoxy equivalent of 50 to 800 g / eq, 0.1 to 15 parts by weight of a curing accelerator, 100 to 200 parts by weight of a curing accelerator based on 100 parts by weight of bisphenol F type epoxy resin having an epoxy equivalent of 500 to 2200 g / 5 to 90 parts by weight of an inorganic filler, and 5 to 80 parts by weight of a color pigment.

Wherein the bisphenol F epoxy curing agent is a mixture of one or more selected from the group consisting of a dicyandiamide epoxy curing agent, an imidazole epoxy curing agent, an acid anhydride epoxy curing agent, and a phenolic epoxy curing agent .

Also, the curing accelerator is one or a mixture of two or more selected from the group consisting of imidazoles, imidazole-modified epoxies, divinyl and noncyclic salts, triphenylphosphine, and metal chelates.

The inorganic filler may be one or a mixture of two or more selected from the group consisting of barium sulfate, calcium carbonate, silica, magnesium hydroxide, alumina hydroxide, titanium dioxide, cray, alumina, mica, wollastonite, do.

The coloring pigment may be one or a mixture of two or more selected from the group consisting of titanium dioxide, bismuth vanadate, cyanine green, carbon black, iron oxide red, iron oxide yellow, navy blue and cyanine blue.

The bisphenol F type epoxy powder coating composition has an average particle size of 30 to 80 占 퐉 and a glass transition temperature (Tg) of 45 to 90 占 폚.

Further, the composition of the present invention further comprises 0.1 to 15 parts by weight of an additive to 100 parts by weight of bisphenol F type epoxy resin,

The additive may be one or a mixture of two or more selected from the group consisting of a dispersing agent, a wetting agent, a gloss-adjusting agent, an additive for improving adhesion, a flame retardant, a pinhole inhibitor and a anti-cratering agent.

The additive may be appropriately added as required by those skilled in the art, and is not a feature of the present invention.

In the present invention, a single resin is used for a bisphenol F type epoxy resin having a limited equivalent range (usually an epoxy powder coating composition is prepared by blending two or more epoxy resins, but in the present invention, bisphenol F type epoxy resin having an equivalent weight of 500 to 2200 g / Free BPA-free epoxy powder coating which is vulnerable to chemical properties and overcomes the limitations of the BPA-free epoxy powder coating, which is not susceptible to chemical properties, and has a high degree of compatibility with BPF (bisphenol F) type epoxy powder Since it does not contain bisphenol A type epoxy which is controversial about environmental hazard through the paint, it can be applied to various ductile iron tubes, steel pipes and drinking water pipes, and the use range of powder coatings can be expanded.

The present inventors have found that a bisphenol F epoxy resin and a specific bisphenol F epoxy curing agent are mixed at a predetermined ratio in order to solve the problems of the BPA type epoxy powder coating, Type epoxy powder coating composition.

The composition can be used inside and outside of cast iron pipe, steel pipe, and fittings by using a fusion bonded epoxy (FBE) coating process. The composition can be used for adhesion, impact resistance, peeling resistance, And there is an advantage that no harmful components to the environment can be detected at all in the dissolution test of the coating film.

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

The bisphenol F type epoxy powder coating composition is based on a diglycidyl ether type epoxy resin produced by the condensation reaction of diphenylmethane (DPM) and epichlorohydrin (ECH) known as bisphenol F (BPF).

Bisphenol F type epoxy resin is a resin having hydrogen (H) in place of methyl group (-CH3) in the molecule of bisphenol A type and has low viscosity and high reactivity as compared with bisphenol A type. It is also excellent in compatibility with other resins, and has excellent low temperature curability, chemical resistance, corrosion resistance and plasticity. Especially, it does not contain bisphenol A which is controversial about environment hazard.

The bisphenol F type epoxy resin coating composition comprises a bisphenol F type epoxy resin and a bisphenol F type epoxy curing agent and further contains a curing accelerator, an inorganic filler and additives such as a polyethylene wax, a polypropylene wax, an acrylic additive and a thermoplastic resin. Mixing, melt dispersion, pulverization and filtration. Various pigments (including colored pigments and colored pigments) can be selected and added in order to obtain various colors.

Each composition will be described in more detail below.

In the present invention, a bisphenol F type epoxy resin having an epoxy equivalent weight of 500 to 2200 g / eq is used alone as the bisphenol F type epoxy resin. This is to prevent appearance degradation of the coating film and ensure the productivity and stability of physical properties of the coating film.

The curing agent is used for curing the epoxy resin, and a bisphenol F type epoxy curing agent having an epoxy equivalent of 50 to 800 g / eq is used. Representative examples include dicyandiamide epoxy-based curing agents, imidazole-based epoxy curing agents, acid anhydride-based epoxy curing agents, and phenolic epoxy curing agents. If necessary, the curing agent may be mixed and used.

The bisphenol F type epoxy curing agent is used in an amount of 5 to 70 parts by weight based on 100 parts by weight of the epoxy resin. If the content of the curing agent is less than the above range, there arises a problem of uncured curing, which makes it difficult to secure the physical properties of the coating film. If the content exceeds the above range, the physical properties of the coating film deteriorate.

The curing of the epoxy resin requires a curing time of 150 to 240 캜 or more, and this curing temperature and time can be shortened by using a curing accelerator.

Examples of the curing accelerator include imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-isopropylimidazole and 2-undecylimidazole, imidazole-modified epoxy, Triphenylphosphine such as butyltriphenylphosphonium bromide, butyltriphenylphosphate oxalate, and butyltriphenylphosphonium chloride, and metal chelate compounds may be used, and if necessary, the aforementioned curing accelerator may be mixed and used.

The curing accelerator is used in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of the epoxy resin. If the content of the curing accelerator is less than the above range, the curing time becomes long. If the content exceeds the above range, the appearance of the coating film is lowered.

The inorganic filler is used in an amount of 5 to 90 parts by weight based on 100 parts by weight of the epoxy resin. Examples of the inorganic filler include barium sulfate, calcium carbonate, silica, magnesium hydroxide, alumina hydroxide, titanium dioxide, cray, alumina, mica, wollastonite and talc. If the amount is less than the above range, sagging phenomenon and hiding power of the coating film will be lowered. If the above range is exceeded, the dispersibility will be lowered and the physical properties of the coating film will be lowered.

The colored pigments are used to impart various colors to the coating composition according to the present invention. Typical examples of such a color pigment include titanium dioxide, bismuth vanadate, cyanine green, carbon black, iron oxide red, iron oxide yellow, navy blue, cyanine blue and the like. The colored pigment is used in an amount of 5 to 80 parts by weight based on 100 parts by weight of the epoxy resin. If the content is less than or more than the above range, the coating film formed of the coating composition may not be sufficiently developed or excessive problems may occur.

The curable bisphenol F type epoxy powder coating composition may further contain additives.

These additives are used for the purpose of preventing cratering, preventing pinholes, controlling sagging, and the like. The additives include a dispersing agent for enhancing the dispersing effect of the resin and the pigment, a wetting agent for enhancing the adhesion between the epoxy resin and the material, a gloss controlling agent for controlling the gloss of the coating film, an additive for improving the adhesion, Flame retardants, pinhole inhibitors, anti-cratering agents, and the like.

The additive is used in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of the epoxy resin. If the content of the additive is less than the above range, an appropriate effect according to the use of the additive can not be obtained. On the other hand, even if the content exceeds the above range, there is no increase in the effect of the additive and thus it is not economical. In some cases, have.

The method for producing the powder coating material for achieving the object of the present invention comprises four steps of premixing, dispersion and grinding.

The first step is a weighing process. It is a process of weighing epoxy resin, curing agent, inorganic filler, additives and so on by using electronic scales and putting them into a mixer according to the designed standard formulation.

In the second step, the pre-mixing step is a step of putting the weighed mixture into a pre-mixing tank and pre-mixing at a high speed.

In the third step, as the dispersion step, the premixed mixture is melt-dispersed at 90 to 120 degrees using a dispersing machine to produce a chip having an appropriate thickness.

In the fourth step, as the crushing step, the chips are crushed by a high-speed mixer and the crushed crushed material is filtered using a sieve of 100 to 200 μm to complete the coating.

The temperature of the disperser is a very important factor in the manufacture of paints. If the temperature of the dispersing machine is too high, the curing reaction may proceed in the dispersing machine and gelation may occur inside the dispersing machine. Therefore, the temperature of the dispersing machine should be maintained at 90 ~ 120 degrees during production.

In the painting process, the type of paint is selected in consideration of the purpose, type and coating conditions of the object to be coated, and the coating method and drying method are determined according to the relationship between the selected paint and the object to be coated.

In the present invention, an electrostatic painting process using a powder coating composition and a solvent-free electrostatic painting process, specifically a FBE (fusion bonded epoxy) coating process, is used as the painting process.

Hereinafter, the present invention will be described in more detail with reference to examples, but the scope of the present invention is not limited by the examples.

<Examples>

A bisphenol F powder coating composition was prepared using the composition shown in Table 1 below.

The bisphenol F type epoxy powder coating composition of the present invention and various examples according to the content of the composition are shown in Table 1 below.

1) Bisphenol F type epoxy resin - equivalent: 1000 to 1200 g / eq (product name: FQ-045-P)

2) Bisphenol F type epoxy resin - equivalent: 1600 to 1800 g / eq (product name: FD-051-P)

3) Bisphenol A type epoxy resin - equivalent: 1100 to 1300 g / eq (product name: YD905)

4) Bisphenol F type epoxy curing agent - equivalent: 200 to 300 g / eq (phenolic system / product name: KDF407)

5) Bisphenol A type epoxy hardener - equivalent: 200 to 400 g / eq (product name: TH982)

6) Imidazole-based curing accelerator (product name: 2MI)

7) Titanium dioxide

8) Barium sulfate

9) Calcium carbonate

10) silica

With respect to the examples of the present invention, which were conducted through the composition of the bisphenol F type epoxy powder coating material described above, the coating film adhesion, the film impact resistance, the coating film flexibility, the coating film scratch resistance, Repeatability and adhesion were measured and the results are shown in Table 3 below.

As shown in Table 3, all of the items were good in Examples 1 and 2, but Comparative Examples 1 and 2 were inferior in corrosion resistance and chemical properties. Furthermore, since Comparative Examples 1 and 2 contain bisphenol A having a controversial environmental hazard, it is difficult to apply it to drinking water use.

From the above results, Examples 1 and 2 according to the present invention show excellent mechanical properties, corrosion resistance and chemical resistance. Further, Examples 1 and 2 do not include bisphenol A, which is an environmentally harmful substance, It can be confirmed that it is applicable to conductors.

Claims (7)

5 to 70 parts by weight of a bisphenol F type epoxy curing agent having an epoxy equivalent of 50 to 800 g / eq, 0.1 to 15 parts by weight of a curing accelerator, 100 to 200 parts by weight of a curing accelerator based on 100 parts by weight of bisphenol F type epoxy resin having an epoxy equivalent of 500 to 2200 g / 5 to 90 parts by weight of an inorganic filler, and 5 to 80 parts by weight of a colored pigment. The method according to claim 1,
Wherein the bisphenol F type epoxy curing agent is one or a mixture of two or more selected from the group consisting of a dicyandiamide epoxy curing agent, an imidazole epoxy curing agent, an acid anhydride epoxy curing agent, and a phenolic epoxy curing agent. Thermosetting bisphenol F type epoxy powder coating composition. 3. The method according to claim 1 or 2,
Wherein the curing accelerator is a mixture of one or more selected from the group consisting of imidazoles, imidazole-modified epoxy, divinyl and non-metyl salts, triphenylphosphine and metal chelates, and thermosetting bisphenol F Type epoxy powder coating composition. The method of claim 3,
Wherein the inorganic filler is a mixture of at least one member selected from the group consisting of barium sulfate, calcium carbonate, silica, magnesium hydroxide, alumina hydroxide, titanium dioxide, cray, alumina, mica, wollastonite, talc , Thermosetting bisphenol F type epoxy powder coating composition. 5. The method of claim 4,
Wherein the color pigment is one or a mixture of two or more selected from the group consisting of titanium dioxide, bismuth vanadate, cyanine green, carbon black, iron oxide red, iron oxide yellow, navy blue and cyanine blue. F type epoxy powder coating composition. 6. The method of claim 5,
Wherein the bisphenol F type epoxy powder coating composition has an average particle size of 30 to 80 占 퐉 and a glass transition temperature (Tg) of 45 to 90 占 폚. 6. The method of claim 5,
0.1 to 15 parts by weight of an additive to 100 parts by weight of bisphenol F type epoxy resin,
Characterized in that the additive is one or a mixture of two or more selected from the group consisting of a dispersing agent, a wetting agent, a gloss-adjusting agent, an additive for improving adhesion, a flame retardant, Curable bisphenol F type epoxy powder coating composition.