KR100808514B1 - Coating method for metal pipe and coated metal pipe by method thereof - Google Patents

Abstract

A metal pipe coating method and a metal pipe coated by the same coating method and provided with an epoxy resin coating layer containing nano-silver are provided to prevent nano-silver from being ionized and eluted even in using a coating composition containing nano-silver and to prevent corrosion of the metal pipe by maintaining adhesion for a long time by the coating layer. A metal pipe coating method comprises a pretreatment step for removing foreign materials attached on the inner or outer peripheral surface of a pipe; a coating composition preparing step for making a coating composition by mixing main material and a hardening agent at the weight rate of 2~7:1; and a coating step for coating the inner or outer peripheral surface of the pipe with the coating composition. The main material consists of epoxy resin of 10~30wt.%, an anti-precipitator of 0.1~12wt.%, non-reactive resin of 5~25wt.%, a thickening agent of 0.1~25wt.%, a filler of 1~95wt.%, nano-silver of 0.1~10wt.%, pigments of 0.1~5wt.%, and an anti-sagging agent of 0.1~5wt.%.

Description

Metal tube coating method and a metal tube comprising an epoxy resin coating layer containing a nano-silver component coated by the coating method {Coating method for metal pipe and coated metal pipe by method

The present invention relates to a metal tube coating method and a metal tube comprising an epoxy resin coating layer containing a nanosilver component coated by the coating method, using the coating composition containing the nanosilver component to coat the inner and outer peripheral surfaces of the various fluid transport tube It relates to a metal tube coated with the method and the coating method.

In general, cast iron pipes or steel pipes are mainly used as fluid transport pipes such as water and sewage.

Metal tubes are usually manufactured in a circular case in a small case, and are manufactured by winding an iron steel sheet in a circular case in a medium and large case.

Due to the nature of such a metal tube, the iron component is dissolved by water flowing therein, thereby deteriorating the water quality, and there is a problem that the inner wall of the metal tube is corroded. In order to prevent such corrosion, the tube is coated with paint.

However, the coated paint may deteriorate from time to time due to its poor adhesiveness, which may cause water to contact the detached surface and corrode. In addition, since the components of the paint contain harmful components to the environment, the possibility of eluting is not completely excluded, and there is a fear that harmful components or heavy metals are included in the drinking water supplied to the home.

In addition, the coating may include nanosilver in the paint for the antimicrobial resistance to the various microorganisms inhabited in the fluid, in this case, the viscosity of the paint is high, the stirring is difficult, the workability may be reduced. In addition, the ionization together with the chlorine component contained for disinfection of the fluid can not be excluded from the possibility of binding to each other and eluted with silver chloride (AgCl), there is a fear that the role of each component is diluted or reduced.

The present invention is to provide a metal tube coating method and a metal tube coated with the coating method excellent in the antimicrobial resistance to microorganisms, the paint coated on the metal tube can maintain the adhesion for a long time, to stably prevent corrosion of the metal tube.

In addition, the present invention is to provide a metal tube coating method and metal tube coated with the coating method that can minimize the dissolution of harmful components in the coating layer, while maintaining excellent antibacterial properties.

Therefore, the present invention in a preferred embodiment the pretreatment process for removing foreign matter on the inner circumferential surface or outer tube surface; The main component and the curing agent component are mixed in a weight ratio of 2 to 7: 1, and the main component is 10 to 30% by weight of epoxy resin, 0.1 to 12% by weight of precipitation inhibitor, and 5 to 25 non-reactive resin, based on the total weight of the main component. A composition for preparing a coating composition to be mixed so as to include a weight%, a thickener of 0.1 to 25% by weight, a filler of 1 to 95% by weight, nano silver of 0.1 to 10% by weight, a pigment of 0.1 to 5% by weight, and a flow inhibitor of 0.1 to 5% by weight; And it provides a metal tube coating method comprising a coating process for coating the prepared coating composition on the inner circumferential surface or the outer surface of the tube.

In the above embodiment, the coating composition preparation step is a charging step of injecting the curing agent component into the raw material container containing the main component; A mixing process of automatically installing a main component and a curing agent component by installing an automatic mixer in a raw material container; And a conveying process of conveying the mixed main ingredient and the hardener component to the spraying device.

In the above embodiment, the coating process may be such that the thickness of the inner circumferential surface coating layer is 0.1 to 2 mm, the thickness of the outer circumferential surface coating layer is 0.5 to 5 mm.

In the above embodiment, the epoxy resin may be a bisphenol-based epoxy resin that does not include a skeleton derived from bisphenol A.

In the above embodiment, the nanosilver may have a particle diameter of 10 ~ 100nm.

In the above embodiment, the filler may be one or a mixture of two or more selected from titanium oxide, barium sulfate, talc, silica and calcium carbonate.

In another aspect, the present invention, the pre-treatment process for removing foreign matter on the outer peripheral surface of the tube; A heating step of heating the tube at 200 to 300 ° C; Primary coating process for welding the powder epoxy (FBE) on the outer peripheral surface of the tube; Secondary coating process for welding coating modified polyethylene powder; Tertiary coating process for welding coating polyethylene powder; Treating the end of the weld; And a pipe outer peripheral surface coating process comprising a cooling step of cooling the temperature of the coating layer to room temperature,

A pretreatment process for removing foreign substances on the inner circumferential surface of the tube; The main component and the curing agent component are mixed in a weight ratio of 2 to 7: 1, and the main component is 10 to 30% by weight of epoxy resin, 0.1 to 12% by weight of precipitation inhibitor, and 5 to 25 non-reactive resin, based on the total weight of the main component. A composition for preparing a coating composition to be mixed so as to include a weight%, a thickener of 0.1 to 25% by weight, a filler of 1 to 95% by weight, nano silver of 0.1 to 10% by weight, a pigment of 0.1 to 5% by weight, and a flow inhibitor of 0.1 to 5% by weight; And it provides a metal tube coating method comprising a coating step for coating the inner circumferential surface of the tube comprising a coating process for coating the prepared coating composition on the inner circumferential surface of the tube.

In the above embodiment, the coating layer on the outer circumferential surface of the tube after the first coating process, the second coating process and the third coating process may be 0.5 to 5 mm.

In another aspect, the present invention provides a metal tube coated by the coating method.

The metal tube according to the embodiment may include a coating layer that does not include a skeleton derived from bisphenol A.

The metal tube according to the embodiment may include a coating layer having a phenols detected by KS D 8502: 2004 test method of 0.005 mg / L or less.

The present invention can provide a metal tube coating method of increasing the antimicrobial resistance to microorganisms by using a coating composition containing a nano-silver component.

In another aspect, the present invention can provide a metal tube coating method that can minimize the possibility that the nano silver component is ionized and eluted even when using the coating composition containing the nano silver component.

In addition, the present invention can provide a metal tube coating method that can prevent the elution of environmental hormones in advance by using a coating composition containing an epoxy resin that does not contain a bisphenol A-derived skeleton.

In another aspect, the present invention can provide a metal tube coating method capable of stably preventing corrosion of the metal tube by maintaining the adhesion of the coating layer for a long time.

On the other hand, the present invention can provide a metal tube excellent in antimicrobial resistance to microorganisms, including a coating layer containing a nanosilver component.

In another aspect, the present invention can be provided by a metal tube coating method that can minimize the risk of nano silver component eluted to provide a metal tube minimized the dissolution of the silver component.

In addition, the present invention can provide a metal tube having a coating layer containing no bisphenol A-derived skeleton.

In another aspect, the present invention can provide a metal tube having a coating layer that can be excellent in adhesion to prevent corrosion of the metal tube.

The metal tube of the present invention includes a coating layer which does not elute substances harmful to the human body in any environment even when applied as a fluid transfer tube while using the coating composition that is harmless to the human body.

That is, the present invention can maintain the advantages of the existing epoxy resin while blocking concerns about environmental hormone release by using an epoxy resin that does not include a bisphenol A-derived skeleton in the coating composition coated on the metal tube, and is coated on the metal tube The coating composition may include a nanosilver component, while providing antimicrobial activity against microorganisms, and may provide a metal tube coating method capable of preventing the dissolution of other harmful substances or nanosilver components in advance.

In addition, the metal tube of the present invention coated by the metal tube coating method does not include a skeleton derived from bisphenol A, and it is found that it is preferable that the phenols detected by the KS D 8502: 2004 test method include a coating layer having 0.005 mg / L or less. It became.

To this end, the metal tube coating method of the present invention includes a pretreatment process of a metal tube, a raw material preparation process for preparing a coating composition by automatic mixing for a proper time, and a coating process.

Hereinafter, with reference to the accompanying drawings of the present invention will be described in more detail.

1 is a block diagram for explaining a coating method according to an embodiment of the present invention.

First, a pretreatment process is performed as in the conventional metal tube coating method, and this pretreatment process is performed by a conventional shot blast method or other known methods, and the abrasives, rust, dust, etc. which are deposited on the surface of the metal tube. Remove it cleanly.

After the pretreatment process as described above is followed by a coating process for coating the coating composition.

The properties of the coating composition are not particularly limited, but it is preferable to use a liquid coating composition.

The present invention is a coating composition to be coated on a metal tube, it is preferable to mix the main component and the curing agent component in a weight ratio of 2 to 7: 1, the main component includes a skeleton derived from bisphenol A with respect to the total weight of the main component 10-30% by weight of non-phenolic epoxy resin, 0.1-12% by weight of precipitation inhibitor, 5-25% by weight of non-reactive resin, 0.1-25% by weight of thickener, 1-95% by weight of filler, 0.1-10% by weight of nano silver, It is preferable to include 0.1 to 5% by weight of the pigment and 0.1 to 5% by weight of the flow inhibitor.

In particular, in mixing the main ingredient and the curing agent component, a step of injecting the curing agent component into the raw material container containing the main component; A mixing process of automatically installing a main component and a curing agent component by installing an automatic mixer in a raw material container; And a transfer step of transferring the coating composition in which the main component and the curing agent component are mixed to the spraying device.

At this time, in the mixing process, the main component and the hardener component are mixed for 1 to 2 minutes using an automatic mixer. The automatic mixer is installed on the upper part of the raw material container, and the stirring blade located inside the raw material container is rotated by the operation of the stirring motor to mix the main component and the hardener component. From this, mixing of the preparation component and the curing agent component can be made easier, and the viscosity of the coating composition can be adjusted.

In addition, the coating composition is preferably maintained at 4 ℃ or more, to improve the workability in spraying or coating the coating composition. To this end, when the external temperature such as winter is lowered to 0 ° C. or lower, it is preferable to maintain the temperature at 4 ° C. or higher by heating the coating composition in a bath. The use of the bath heating method is to prevent hardening immediately when the coating composition is directly heated, and this bath heating method is a bath bath in which a raw material container in which a coating composition is stored is placed in a bath tank in which a room temperature liquid is stored. The tank may be heated to maintain the coating composition at an appropriate temperature. As for the coating composition at this time, it is more preferable that it is a liquid form.

In addition, the metal tube coating method of the present invention is subjected to a coating process for coating on the inner circumferential surface or outer circumferential surface using the prepared coating composition, airless spray (airless spray), air spray (air spray), roller (roller), brush (brush) It may be coated by a method such as).

In order to coat the coating composition on the inner circumferential surface or the outer circumferential surface of the metal tube, it is coated on the inner circumferential surface or the outer circumferential surface of the metal tube by using an injector, which will be described with reference to FIG. The coating layer 11 is formed on the metal tube by rotating (10) and applying the coating composition while spraying the coating composition from the nozzle of the spray device 30 while moving in the direction of the center line of the metal tube.

In addition, the inner circumferential surface coating layer preferably has a thickness of 0.1 to 2 mm, and the outer circumferential surface coating layer has a thickness of 0.5 to 5 mm.

Hereinafter, the raw material included in the coating composition to be coated according to the metal tube coating method of the present invention will be described in detail.

Epoxy resin mainly uses bisphenol A as a raw material, which is a substance that can act as a synthetic estrogen, and is an environmental hormone that causes neurodevelopment problems even in a very small amount. Small amounts may melt.
The bisphenol A type epoxy resin mainly used as a conventional epoxy resin includes a skeleton derived from bisphenol A of the general formula (1).

<Formula 1>

Wherein n is an integer of 1 or more.

The bisphenol A type epoxy resin has excellent stiffness and heat resistance because the bisphenol skeleton has a high symmetry and a rigid structure, and has excellent chemical resistance because the aromatic ring and the ether bond are the main components, and the ether bond of the main chain bond is suitable for free rotation. It has plasticity because it makes it possible. In addition, since the hydrophilic alcoholic secondary hydroxyl group (-OH) and the hydrophobic hydrocarbon group are regularly distributed, the adhesion is good, and the terminal epoxy group and the -OH group provide excellent reactivity.
The bisphenol A epoxy resin is widely used due to such excellent performance, but since the viscosity is high at room temperature, the viscosity of the bisphenol A epoxy resin should be lowered depending on the purpose of use. In case of irritating odor and strong skin irritation, workability is lowered, thereby limiting use. In addition, there is a risk of using the environmental hormone component as mentioned above as a raw material.
Therefore, in the present invention, it is preferable to use a bisphenol-based epoxy resin that does not contain the repeating unit represented by Chemical Formula 1, that is, does not contain a skeleton derived from bisphenol A. As a result, the viscosity of the resin itself is low, so it is not necessary to use a diluent harmful to the human body, and since the environmental hormone component is not used as a raw material, the risk can be significantly lowered.
As a bisphenol-type epoxy resin which does not contain such a repeating unit of Formula 1, a bisphenol F-type epoxy resin, a bisphenol AD epoxy resin, etc. are mentioned, for example. In this case, the bisphenol A epoxy resin may have a performance equivalent to that of the bisphenol A epoxy resin, and the chemical resistance is slightly higher than that of the bisphenol A epoxy resin, and the mechanical properties such as adhesion and flexibility, water resistance, durability and heat resistance, etc. It is about the same as bisphenol-A epoxy resin.
The coating composition used in the present invention comprises 10 to 30% by weight of the epoxy resin with respect to the total weight of the coating composition, which is related to the adhesion of the coating composition to the inner peripheral surface of the coating composition, the flowability of the coating composition, fluidity And viscosity control.

In addition, it is preferable to use the nano-silver particle size of 10 ~ 100nm in the coating composition, the higher the purity, the better the antibacterial properties. Particularly, in the case of containing nanosilver, it is difficult to stir the paint. In the present invention, the viscosity of the coating composition is not difficult to be caused by the addition of nanosilver, so that the viscosity may be considered and stable antimicrobial properties may be obtained. It is preferable to include 5% by weight.

Precipitation preventive agent is to help stirring the other components to be added and to maintain a uniformly mixed state, if known, can be used without particular limitation, containing 0.1 to 10% by weight relative to the total weight of the coating composition desirable.

The non-reactive resin is added to improve the fluidity of the coating composition, and particularly known ones such as benzyl alcohol, furopryl alcohol, phenyl xylyl ethane (Hysol), dioctyl phthalate (DOP) and dibutyl phthalate (DBP) are particularly known. It can be used without being limited.

In the present invention, in consideration of the fluidity and workability of the coating composition, it is preferable to include 5 to 20% by weight based on the total weight of the coating composition.

The thickener can be used without particular limitation as long as it is known to prevent it from flowing down during the coating operation. In the present invention, in consideration of the fluidity and workability of the coating composition, it is preferable to include 0.1 to 20% by weight relative to the total weight of the coating composition.

In the coating composition coated on the metal tube of the present invention, one or a mixture of two or more selected from titanium oxide, barium sulfate, talc, silica, and calcium carbonate may be used. Such a filler can not only adjust the viscosity of the coating composition itself according to the type and content used, but also improve the adhesion, durability and water resistance of the coating film when coated on the coating, in the present invention, It is preferable to use 1 to 80% by weight based on the total weight of the composition.

On the other hand, it may further comprise a pigment and a flow inhibitor, if known, can be used without particular limitation, it is preferable to use 0.1 to 5% by weight based on the total weight of the coating composition.

The above components are mixed and used as a main component, and a hardening | curing agent is mixed here. The curing agent is used to cure the epoxy resin at room temperature, and is not particularly limited as long as it is known, and amines, acid anhydrides, polyamide resins, polysulfide resins, and the like may be used. A modified amine can also be used, and latent curing agents, such as monoethylamine for extending the pot life, can also be used. It is preferable to mix a main component and a hardening | curing agent component in the weight ratio of 2-7: 1.

On the other hand, Figure 3 is a block diagram illustrating a coating method according to another preferred embodiment of the present invention, Figure 4 is a schematic diagram of the process of heating the metal tube, Figure 5 is to form a three-layer coating layer on the outer peripheral surface of the metal tube It is a schematic diagram explaining the method, FIG. 6: is sectional drawing which shows the state in which the three-layer coating layer was formed in the outer peripheral surface of a metal tube, and the coating layer was formed in the inner peripheral surface.

The metal tube of the present invention may be coated on its outer circumferential surface by using the coating composition described above, and may include a known three-layer coating layer.

That is, the metal tube 10 is heated in the heating furnace 20, and the heating temperature at this time is a temperature at which the coating agent to be coated is melted on the surface of the metal tube and a close coating can be performed, that is, a coating powder. It is heated higher than the melting temperature, and is subjected to a process of heating at 200 to 300 ° C, more preferably 230 ± 20 ° C.

After the heating process as described above to form a coating layer by coating the coating powder on the surface of the metal tube 10, the metal tube is coated on the surface of the metal tube is treated by the end can be welded, immersed in a cooling water tank The metal tube is forcibly cooled by spraying cooling water onto the metal tube. The reason for forcibly cooling the metal tube is to form a film having a uniform thickness while the film structure on the surface of the metal tube is dense.

At this time, the coating layer formed on the outer circumferential surface of the metal tube 10 is composed of three layers. For this purpose, the first coating layer 21 is coated by powder epoxy 30a (FBE; Fusion Bonded Epoxy) on the outer circumferential surface of the metal tube 10. Forming a primary coating process; A second coating step of forming a second coating layer 22 with modified polyethylene powder 30b on one surface of the first coating layer 21; The third coating process of coating the polyethylene powder 30c as the third coating layer 23 on the second coating layer 22 may be performed sequentially.

The coating process will be described in more detail. In order to sequentially prepare a deposition tank containing the powder epoxy 30a, the modified polyethylene powder 30b having good adhesiveness, and the polyethylene powder 30c, the metal tube uniformly heated to a predetermined temperature While rotating (10), soak in the immersion tank sequentially and take out. After such a process is performed, the powder epoxy 30a is melted by the heated heat on the outer circumferential surface of the metal tube 10 to be bonded to the outer circumferential surface of the metal tube 10 to form the first coating layer 21. This is because the powdered epoxy 30a in the molten state is bonded to the outer circumferential surface of the metal tube 10, and the adhesive is physically bonded and the powder epoxy 30a having the polar group of the secondary hydroxyl group is attached to the metal tube ( 10) It has excellent adhesion by hydrogen bonding with the surface.

The second coating layer 22 is formed while uniformly coating the modified polyethylene powder 30b on the surface of the first coating layer 21 formed as described above. The modified polyethylene powder 30b is formed by heat remaining in the metal tube 10. ) Is melted and coated to react with the powder epoxy 30a sufficiently.

Thereafter, the polyethylene coating 30c is coated on the surface of the second coating layer 22 to form the third coating layer 23. At this time, the polyethylene powder 30c is attached and coated while melting by the heat of the metal tube 10. The coating process of coating with the three layers described above is finished within 5 minutes, so that the temperature of the heated metal tube 10 is maintained almost intact, and thus there is no problem in forming a welding coating layer up to three layers.

As described above, the coating layer on the outer circumferential surface of the tube subjected to the third coating process is preferably 0.5 to 5 mm in protecting the surface of the tube.

On the other hand, the three-layer coating method of the outer circumferential surface of the metal tube 10, in addition to the deposition method as described above, a method of coating by spraying or dropping the coating powder around the metal tube is also possible.

As described above, after the coating layers 21, 22, and 23 are formed on the outer circumferential surface of the metal tube 10, the inner circumferential surface is pretreated after the inner circumferential surface as described above, and does not include a skeleton derived from bisphenol A with respect to the total weight of the main component. Bisphenol-based epoxy resin 10-30% by weight, precipitation inhibitor 0.1-12% by weight, non-reactive resin 5-25% by weight, thickener 0.1-25% by weight, filler 1-95% by weight, nano silver 0.1-10% by weight, pigment The coating layer 11 may be formed by coating a coating composition in which a main component and a curing agent component including 0.1 to 5 wt% and 0.1 to 5 wt% of a flow inhibitor are mixed at a weight ratio of 2 to 7: 1.

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

<Example 1>

A steel pipe having an outer diameter of 813 mm, a thickness of 8.00 mm, and a length of 6 m was subjected to a pretreatment step of removing rust and foreign matter by a short blast process, and cut and molded to an appropriate size. After the bending and welding at the required angle, the weld was cleaned.

On the other hand, based on the total weight of the main component, 20% by weight of bisphenol F-type epoxy resin (epoxy equivalent 175), a mixture of 1-xylyl-1,3-diphenylbutane and bis (?-Methylbenzyl) xylene as a non-reactive resin 12 wt%, 1.2 wt% of acrylic thickener as thickener, 1.2 wt% of nano silver (BC nanotech) having a particle size of 80 nm as silver component, 1.2 wt% of clay as precipitation inhibitor, 2.4 wt% of metal phosphate rust-preventive pigment , 0.5% by weight of the castor oil derivative as a flow inhibitor, 61.5% by weight of the filler was mixed, wherein 32.5% by weight of silica, 17.9% by weight of titanium oxide, 31.7% by weight of barium sulfate, 17.9% by weight of talc Used as the subject ingredient. Here, polyamide amine was mixed as a curing agent, but the weight ratio of the main agent and the curing agent was 2: 1, and the mixture was stirred for 1 to 2 minutes by an automatic mixer, and the prepared coating solution was 7 to 8 liters.

The coating solution was coated on the inner circumferential surface and the outer circumferential surface of the steel pipe, and the outer circumferential surface was coated so that the thickness of the coating layer was 2 to 3 mm and the inner circumferential surface was 0.4 to 0.6 mm.

<Example 2>

In Example 1, the outer circumferential surface of the steel pipe was coated as follows. That is, after heating in a heating furnace of 250 ℃ 4 to 5kg by coating the epoxy powder coating on the outer circumferential surface of the steel pipe, the coating coating by spraying 10 ~ 11kg of modified polyethylene powder while maintaining the temperature. Thereafter, while maintaining the temperature by spraying 36 ~ 38kg polyethylene powder by coating coating. Next, the cooling layer was sprayed and cooled to room temperature to cure the coating layer. After curing, the thickness of the coating layer was 2 to 3 mm.

And the coating liquid coated on the inner circumferential surface of the steel pipe was as follows.

20% by weight of bisphenol F-type epoxy resin (epoxy equivalent 175) relative to the total weight of the main component, 1-xysilyl-1,3-diphenylbutane and bis (α-methylbenzyl) xylene and 1- as non-reactive resins 10% by weight of a mixture of xylyl-1- (3-α-methylbenzylphenyl) ethane, 1.1% by weight of an acrylic thickener as a thickener, and 1.5% by weight of nanosilver (BC nanotech) having a particle size of 100 nm as a silver component. 1.2 weight% of tocopherol derivatives, 2.4 weight% of metal phosphate-based rust-preventive pigments, and 0.5 weight% of castor oil derivatives as flow inhibitors were mixed, and 63.3 weight% of fillers were mixed. Titanium 20% by weight, 30.8% by weight of barium sulfate, and 16.8% by weight of talc were mixed and used as the main component. Here, polyamide amine was mixed as a curing agent, but the weight ratio of the main agent and the curing agent was 2: 1, and the mixture was stirred for 1 to 2 minutes by an automatic mixer, and the coating solution was 7 to 8 liters.

The coating solution was coated on the inner circumferential surface of the steel pipe, and the inner circumferential surface was coated so that the thickness of the coating layer was 0.4 to 0.6 mm.

The inner circumferential surface of the steel pipe coated in Examples 1 and 2 was evaluated by the test method of KS D 8502: 2004. As a result, there was no abnormality in the blendability, workability, appearance, bending test, direct and indirect impact test, low temperature and high temperature repetition test, adhesion test, salt spray test, moisture resistance test, taste and smell of the present invention. The heating residue in the paint was 95% by weight, the curing drying time at 20 ° C was 10 hours, the turbidity was 0.5 or less, and the chromaticity was 1 or less. In addition, cyanide, phenol, epichlorohydrin, toluene diisocyanate and amines were not detected at all. In addition, AgCl was not eluted when the same sample as the inner circumferential surface of the coated steel pipe was immersed in tap water containing 40 ° C. for 24 hours.

Therefore, the metal tube coated by the coating method of the present invention not only had no abnormality in adhesion, durability and appearance of the coating layer, but also the detection of harmful components such as phenols could be minimized, and by using a coating liquid containing no bisphenol A, the environment It can be seen that the risk of dissolution of hormones can be prevented. In addition, it can be seen that the nano silver component included in the coating layer for the antimicrobial activity against microorganisms also minimized the risk of inclusion in drinking water.

Meanwhile, in Example 1, the coating solution coated on the inner circumferential surface was applied to 10 cm × 10 cm metal tube specimens, and the growth effect of bacteria on the coating film after standing at room temperature was measured by the shake flask test method film adhesion method (JIS Z 2801: 2000). Was tested.

(1) Antibacterial activity test against Staphylococcus aureus

Using American Type Culture Collection No.6538P as the inoculating strain, the test bacteria were tested at 35 ± 1 ° C., RH 90%, and after 24 hours of stationary culture.

division Control Example 1 Early strain 2.0 ± 0.1 × 10 ⁵ / ml 2.0 ± 0.1 × 10 ⁵ / ml 24 hours later 5.3 ± 0.1 × 10 ⁵ / ml <10 Antimicrobial activity (log) - 4.7

* Tester: FITI tester

* Antibacterial effect: Good judgment when antibacterial activity log value is 2.0 or more

(2) Antibacterial activity test against E. coli

As an inoculation strain, American Type Culture Collection No.8739 was used, and the test bacteria were tested at 35 ± 1 ° C., RH 90%, and after 24 hours of stationary culture.

division Control Example 1 Early strain 2.0 ± 0.1 × 10 ⁵ / ml 2.0 ± 0.1 × 10 ⁵ / ml 24 hours later 1.6 ± 0.1 × 10 ⁷ / ml <10 Antimicrobial activity (log) - 6.2

* Tester: FITI tester

* Antibacterial effect: Good judgment when antibacterial activity log value is 2.0 or more

In addition, in order to test whether the antimicrobial activity changes according to the temperature change, the above Staphylococcus aureus was prepared under the same conditions, treated at -20 ° C for 1 hour, 20 ° C for 30 minutes, and 80 ° C for 1 hour, and then repeated three times. The viable cell count after time was confirmed.

As a result, in the case of changing the temperature in the embodiment of the present invention showed a reduction rate of 99.9% to 10 or less viable bacteria.

Therefore, when the coating solution of the present invention is applied to the inner circumferential surface, the antimicrobial activity was very excellent, and even if the temperature was changed, the antimicrobial activity was found to be stable.

1 is a block diagram for explaining a coating method according to an embodiment of the present invention,

2 is a view schematically showing a method of applying a coating liquid to the inner circumferential surface of the metal tube by the coating method according to an embodiment of the present invention,

Figure 3 is a block diagram for explaining a coating method according to another preferred embodiment of the present invention,

4 is a view showing a process of heating a metal tube of the metal tube outer circumferential coating method by the coating method according to another embodiment of the present invention,

5 is a view showing a method of forming a three-layer coating layer on the outer circumferential surface of the metal tube of the outer surface coating method of the metal tube by the coating method according to another embodiment of the present invention,

6 is a view illustrating a state in which a three-layer coating layer is formed on an outer circumferential surface of a metal tube and a coating layer is formed on an inner circumferential surface of a metal tube outer circumferential surface coating method according to another preferred embodiment of the present invention.

* Explanation of the symbols of the main parts of the drawings

10 metal tube 11 coating layer

20: heating furnace 21: first coating layer

22: second coating layer 23: third coating layer

30: injector 30a: powder epoxy

30b: modified polyethylene powder 30c: polyethylene powder

Claims (11)

A pretreatment process for removing foreign matter from the inner circumferential surface of the tube or the outer circumferential surface of the tube; The main component and the curing agent component are mixed in a weight ratio of 2 to 7: 1, and the main component is 10 to 30% by weight of epoxy resin, 0.1 to 12% by weight of precipitation inhibitor, and 5 to 25 non-reactive resin, based on the total weight of the main component. A composition for preparing a coating composition to be mixed so as to include a weight%, a thickener of 0.1 to 25% by weight, a filler of 1 to 95% by weight, nano silver of 0.1 to 10% by weight, a pigment of 0.1 to 5% by weight, and a flow inhibitor of 0.1 to 5% by weight; And Metal tube coating method comprising a coating process for coating the prepared coating composition on the inner circumferential surface or the outer surface of the tube. The method of claim 1, The composition for preparing a coating may include an input step of injecting a curing agent component into a raw material container including a main component; A mixing process of automatically installing a main component and a curing agent component by installing an automatic mixer in a raw material container; And A metal tube coating method comprising a transfer step of transferring a coating composition mixed with a main component and a curing agent component to a spraying device. The method of claim 1, Coating process is a metal tube coating method characterized in that the inner peripheral surface coating layer thickness is 0.1 ~ 2mm, the outer peripheral surface coating layer is 0.5 ~ 5mm thickness. The method of claim 1, Epoxy resin is a bisphenol-type epoxy resin which does not contain the frame | skeleton derived from bisphenol A, The metal tube coating method characterized by the above-mentioned. The method of claim 1, Nano silver is a metal tube coating method characterized in that the particle diameter is 10 ~ 100nm. The method of claim 1, And the filler is one or a mixture of two or more selected from titanium oxide, barium sulfate, talc, silica and calcium carbonate. Including the outer circumferential surface coating process and the inner circumferential surface coating process, Tube outer peripheral surface coating process, the pre-treatment process for removing foreign matter on the outer peripheral surface of the tube; A heating step of heating the tube at 200 to 300 ° C; Primary coating process for welding the powder epoxy (FBE) on the outer peripheral surface of the tube; Secondary coating process for welding coating modified polyethylene powder; Tertiary coating process for welding coating polyethylene powder; Treating the end of the weld; And It includes a cooling step of cooling the temperature of the coating layer to room temperature, Coating process of the inner circumferential surface of the tube, pretreatment process for removing foreign matter on the inner circumferential surface of the tube; The main component and the curing agent component are mixed in a weight ratio of 2 to 7: 1, and the main component is 10 to 30% by weight of epoxy resin, 0.1 to 12% by weight of precipitation inhibitor, and 5 to 25 non-reactive resin, based on the total weight of the main component. A composition for preparing a coating composition to be mixed so as to include a weight%, a thickener of 0.1 to 25% by weight, a filler of 1 to 95% by weight, nano silver of 0.1 to 10% by weight, a pigment of 0.1 to 5% by weight, and a flow inhibitor of 0.1 to 5% by weight; And Metal tube coating method comprising a coating step of coating the prepared coating composition on the inner peripheral surface of the tube. The method of claim 7, wherein Metal coating method characterized in that the coating layer of the outer peripheral surface of the tube after the first coating process, the second coating process and the third coating process is 0.5 ~ 5㎜. Metal tube coated by the metal tube coating method of any one of claims 1 to 8. The method of claim 9, A metal tube comprising a coating layer containing no skeleton derived from bisphenol A. The method of claim 9, KS D 8502: 2004 Metal tube comprising a coating layer having a phenols detected by the test method is 0.005 mg / L or less.

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