KR102208535B1 - Method for manufacturing multi layered aluminium pipe for cooling and heating system and multi layered aluminium pipe produced thereby - Google Patents

Abstract

The present invention relates to a method for manufacturing a multi-layered aluminum pipe for a cooling and heating device and a multi-layered aluminum pipe manufactured thereby. More specifically, the present invention relates to the method for manufacturing a multi-layered aluminum pipe for a cooling and heating device which withdraws an aluminum pipe at proper thickness and evenly coats an adhesive layer and a resin layer on a surface of the pipe at the proper thickness so as to have excellent heat resistance, excellent salt damage resistance, and improved pressure resistance strength of at least allowance level in a cooling and heating device, and the multi-layered aluminum pipe manufactured thereby.

Description

Manufacturing method of multi-layered aluminum pipe for air conditioner and multi-layered aluminum pipe manufactured thereby {METHOD FOR MANUFACTURING MULTI LAYERED ALUMINIUM PIPE FOR COOLING AND HEATING SYSTEM AND MULTI LAYERED ALUMINIUM PIPE PRODUCED THEREBY}

The present invention provides a method for manufacturing a multi-layered aluminum pipe for air conditioners and a multi-layered aluminum pipe that has excellent workability and corrosion resistance of pipes, and has improved heat resistance, salt resistance and pressure resistance compared to existing metal pipes, and About.

Existing metal pipes, which are mainly used for cycles of air conditioners, have a high manufacturing cost and high thermal conductivity, so there is a problem that cold air or heat is taken to the outside and the temperature drops. In other words, there is a disadvantage in that effective cooling and heating cannot be performed because cold air and heat are taken to the outside of the non-insulated metal pipe.

Accordingly, aluminum pipes that are lighter and cost-saving than existing metal pipes of air conditioners are being studied as a new material. However, aluminum piping has a price competitiveness compared to conventional metal piping and is effective because of relatively low thermal conductivity, but has a disadvantage in that the surface is corroded when exposed to air. In addition, the aluminum pipe has a weak impact resistance due to an external impact, and has a limit in effectively blocking cold air or heat emitted from the air conditioner.

Conventional Korean Patent Laid-Open No. 10-2006-0115360 discloses a header pipe made of aluminum with a plurality of partition grooves, a heat dissipation tube made of aluminum with a plurality of fluid flow holes through which the refrigerant flows through the header pipe, a heat radiation fin made of aluminum, and aluminum. Disclosed is a heat exchanger for an air conditioner comprising a baffle of ash. However, as the header pipe, the heat dissipation tube, the heat dissipation fin and the baffle of the heat exchanger for the air conditioner are all used as aluminum material, the light weight is eliminated, but the aluminum material has a disadvantage in that it is vulnerable to pressure resistance and surface corrosion.

Therefore, it is necessary to research and develop a new aluminum pipe that prevents surface corrosion while having price competitiveness and light weight with respect to the pipe material used in the cycle of the air conditioner and has excellent pressure resistance.

Korean Patent Publication No. 10-2006-0115360

In order to solve the above problems, the present invention provides a method of manufacturing a multi-layered aluminum pipe for air conditioner and heating system in which the roundness is improved and the pipe is prevented from being pressed by including drawing, washing, and scratching processes. The purpose.

In addition, it is an object of the present invention to provide an aluminum pipe having a multi-layered structure for an air conditioner manufactured by the above method, which has excellent adhesion between an aluminum pipe and a resin layer, and has improved heat resistance, salt resistance and pressure resistance of the pipe.

The object of the present invention is not limited to the object mentioned above. The object of the present invention will become more apparent from the following description, and will be realized by the means described in the claims and combinations thereof.

The multi-layered aluminum pipe for the air conditioner according to the present invention is drawn with a drawing die and washed with a detergent containing a small amount of harmful components to improve roundness, prevent the pipe from being pressed, and at the same time improve stability problems for the human body and the environment. I can.

In addition, the multi-layered aluminum pipe for the air conditioner may have excellent pressure resistance and resistance to salt damage by drawing the aluminum pipe to an appropriate thickness. In addition, it is possible to improve the adhesion between the aluminum pipe and the resin layer by physically scratching the surface of the drawn pipe and then uniformly coating the adhesive layer and the resin layer having an appropriate thickness in turn. In addition, it has price competitiveness and is flexible, so it has excellent workability and can improve corrosion resistance and heat resistance.

1 is a block diagram of an apparatus for manufacturing a multi-layered aluminum pipe for an air conditioner according to the present invention. Referring to FIG. 1, the aluminum pipe of the multilayer structure for the air conditioner of the present invention is drawn, washed, scratched, and coated with an adhesive layer while the aluminum pipe in the form of a circular tube is transferred from the unloading machine 1 to the rewinding machine 12. It can be carried out in an automated, continuous process that sequentially performs the formation of the formation. The apparatus for manufacturing a multi-layered aluminum pipe for an air conditioner of FIG. 1 includes an unloading machine (1), a straightener (2), a drawing die machine (3), a washing machine (4), a dryer (5), a scratch generator (6), and an adhesive. It includes an applicator 7, a high frequency induction heater 8, an extrusion coating machine 9, a cooler 10, a take-up machine 11 and a rewinder 12.

Specifically, the unloading machine 1 is a device for supplying an aluminum pipe and serves to supply an aluminum pipe wound around a bobbin to the straightener 2. The straightener (2) is a device that straightens the aluminum pipe that is unwound in a coiled state on the bobbin of the unloading machine (1), and is straightened while the aluminum pipe passes between the upper and lower rollers of the straightener (2). I can. The drawing die machine 3 is a device for drawing the pipe into a circular shape having a predetermined thickness, not an ellipse, by adjusting the outer diameter and the inner diameter of the aluminum pipe. The drawing dice 3 may include a sealed outer case and an auxiliary system for filtering and circulating contaminated drawing oil so that the surroundings are not contaminated due to leakage or leakage of the drawing oil.

The washing machine 4 is a device for removing foreign substances adhering to the surface of the drawn aluminum pipe. The dryer 5 is a device for drying the aluminum pipe that has passed through the washing machine 4. The scratch generator 6 is a device for forming microscopic scratches on the surface of the aluminum pipe, and may improve adhesive strength between the pipe surface and the resin layer. The scratch generator 6 may include a brush for generating scratches. The adhesive applicator 7 is a device for coating an adhesive layer on the scratched surface of the aluminum pipe.

The high frequency induction heater 8 is a device for preheating the surface of an aluminum pipe coated with an adhesive layer to an appropriate temperature. The extrusion coating machine 9 is a device for coating the surface of the adhesive layer of the aluminum pipe with a resin layer by extruding the resin layer composition. The cooler 10 is a device for cooling an aluminum pipe coated with a resin layer with cooling water. The take-off device 11 is a device that provides a conveying force to the cooled aluminum pipe and transports the aluminum pipe according to a continuous process of the original line. The rewinder 12 is a device for winding the aluminum pipe that has passed through the take-up machine 11 on a bobbin.

The multi-layered aluminum pipe for the air conditioner of the present invention can be manufactured by a continuous process by passing through the manufacturing apparatus of FIG. 1 in sequence. Specifically, the method of manufacturing a multi-layered aluminum pipe for an air conditioner includes (S1) manufacturing a drawn aluminum pipe; (S2) washing step; (S3) scratch forming step; (S4) forming an adhesive layer; (S5) preheating step; And (S6) forming a resin layer.

More specifically, the method of manufacturing a multi-layered aluminum pipe for an air conditioner of the present invention comprises: washing the drawn aluminum pipe with a cleaning agent; Forming a scratch having a thickness of 0.05 ~ 0.3 ㎛ on the surface of the cleaned aluminum pipe; Forming an adhesive layer having a thickness of 0.01 to 1 mm by applying an adhesive composition on the surface of the scratched aluminum pipe; Preheating the aluminum pipe on which the adhesive layer is formed with a high frequency induction heater; And forming a resin layer having a thickness of 0.01 to 2 mm by coating a resin layer composition on the adhesive layer of the preheated aluminum pipe, wherein the drawn aluminum pipe has an inner diameter of 3 to 20 mm and an outer diameter of 6 to 22 mm, and may have a thickness of 0.4 to 2 mm.

The method of manufacturing the multi-layered aluminum pipe for the air conditioner of the present invention will be described in detail for each step as follows.

(S1) Step of manufacturing the drawn aluminum pipe

The (S1) step of manufacturing the drawn aluminum pipe may be a step of manufacturing the drawn aluminum pipe by inserting the aluminum pipe into the drawing die. Drawing dies, which are generally used, refer to a facility that pulls out a pipe with a size smaller than that of a large-diameter pipe. In the present invention, in order to improve the roundness of the drawing dies, it is preferable to use the same size of the inlet diameter and the discharge diameter. In general, the aluminum pipe wound around the bobbin is straightened by passing through the straightener 20 in the unloading machine 10, but there is a problem in that it is difficult to guarantee the roundness because the stress remains inside and is in an elliptical state away from the epicenter. In the present invention, in order to compensate for this, a drawing die is provided between the straightener 20 and the washing machine 40 section, and the process of drawing the aluminum pipe into a true circle having the same thickness as in step (S1) may be performed. In addition, since the aluminum pipe is wound on the bobbin and transported, the roundness of the pipe is distorted and the pipe is pressed during the winding.However, by drawing with a drawing die through the step (S1), the roundness can be improved and the pipe can be prevented from being pressed. have. The aluminum pipe may have an inner diameter of 3 to 20 mm, an outer diameter of 6 to 22 mm, and a thickness of 0.4 to 2 mm. Preferably, the aluminum pipe has an inner diameter of 5.2 to 10 mm, an outer diameter of 6 to 11.5 mm, and a thickness of 0.8 to 1.5 mm, and most preferably the aluminum pipe has an inner diameter of 5.4 mm, It has an outer diameter of 6.4 mm and can be drawn to a thickness of 1 mm. In this case, if all of the inner diameter, outer diameter, and thickness range of the aluminum pipe are not satisfied, the internal pressure strength of the aluminum pipe rapidly decreases due to hot water of 100° C. or higher passing through the pipe, and corrosion may occur.

The material of the aluminum pipe may be aluminum or aluminum alloy having excellent corrosion resistance, stiffness, and molding processability. The aluminum (1000 series) has good corrosion resistance, excellent light reflectivity and thermal conductivity, and excellent welding and molding processability.

In addition, the aluminum alloy is Al-Cu-based alloy (2000 series), Al-Mn-based alloy (3000 series), Al-Si-based alloy (4000 series), Al-Mg-based alloy (5000 series), Al-Mg-Si It may be one or more selected from the group consisting of alloys (6000 series), Al-Zn-Mg alloys (7000 series), and Al-Zn-Cu alloys (7000 series). The aluminum alloy has particularly excellent stiffness, formability, weldability and corrosion resistance.

(S2) washing step

The (S2) washing step may be a step of washing the drawn aluminum pipe with a detergent. Conventional cleaning agents for cleaning aluminum pipes contain a large amount of toxic components harmful to the human body, and are highly volatile, causing respiratory disease. In order to improve this, in the present invention, a cleaning agent containing components that are relatively less harmful to the human body may be used compared to conventional cleaning agents. Preferably, the cleaning agent may include 50 to 70% by weight of dimethyl carbonate, 25 to 40% by weight of methylene chloride, and 1 to 10% by weight of a chlorine-based stabilizer. The chlorine-based stabilizer may be chlorine dioxide. These cleaning agents contain a small amount of harmful ingredients compared to conventional cleaning agents, so that environmental pollution can be relatively reduced. In the step (S2), foreign substances such as oil or dust remaining on the surface of the aluminum pipe may be removed by washing the drawn aluminum pipe with a cleaning agent. Between the steps (S2) and (S3), the washed aluminum pipe may be dried by hot air drying using a dryer 50.

(S3) Scratch formation step

The (S3) scratch forming step may be a step of forming a scratch having a thickness of 0.05 to 0.3 μm on the surface of the cleaned aluminum pipe. In the step (S3), in order to improve adhesion between the surface of the aluminum pipe and the resin layer composition, in addition to forming an adhesive layer, a physical property of forming scratches may be applied. Through the step (S3), the surface of the aluminum pipe may be scratched to form an embossed shape. The step (S3) may be treated such that the surface of the aluminum pipe has a scratch of 0.05 to 0.3 µm, preferably 0.1 to 0.3 µm, more preferably 0.15 to 0.25 µm, and most preferably 0.2 µm. If the depth of the scratch is less than 0.05 μm, the adhesion between the surface of the aluminum pipe and the resin layer composition may decrease. Conversely, if the depth of the scratch is more than 0.3 µm, impurities may adhere to the scratched surface or the coating thickness of the adhesive layer may not be formed uniformly, resulting in uneven adhesion. By forming a scratch on the surface of the aluminum pipe through the step (S3) by a physical method, it is possible to improve the adhesion between the surface of the aluminum pipe and the resin layer composition.

(S4) Step of forming an adhesive layer

The (S4) step of forming an adhesive layer may be a step of forming an adhesive layer having a thickness of 0.01 to 1 mm by applying an adhesive composition on the surface of the scratched aluminum pipe. In the past, this was carried out by applying a low-viscosity one-component adhesive to the surface of an aluminum pipe in a free-fall method. However, with this method, there is a problem that the adhesive is not evenly applied to the surface of the aluminum pipe, and a section is omitted. In the present invention, the adhesive composition may be applied to the surface of the scratched aluminum pipe in step (S4) by spray coating, gravure coating, casting, or doctor blade method to form an adhesive layer. Preferably, it can be applied by a spray coating method. The spray coating method may improve adhesive strength by spraying the adhesive composition through a spray nozzle to uniformly apply it to the surface of a scratched aluminum pipe.

In the step (S4), the adhesive composition comprises 12 to 20% by weight of a bisphenol-based resin; 40-50% by weight of toluene; And 30 to 40% by weight of methyl ethyl ketone. Preferably, the adhesive composition comprises 13 to 19% by weight of a bisphenol-based resin; 43-49% by weight of toluene; And methyl ethyl ketone 32 to 38% by weight; may include. More preferably, the adhesive composition comprises 16 to 18% by weight of a bisphenol-based resin; 45-48% by weight of toluene; And 34 to 36% by weight of methyl ethyl ketone. Most preferably, the adhesive composition comprises 18% by weight of a bisphenol-based resin; 47% by weight toluene; And 35% by weight of methyl ethyl ketone; may include. In particular, the bisphenol-based resin of the adhesive composition is excellent in durability as well as adhesiveness, and thus mechanical properties of metal materials can be improved. Specifically, the bisphenol-based resin may be epichlorohydra bisphenol A resin.

The adhesive layer may have a coating thickness of 0.01 to 1 mm, preferably 0.05 to 0.8 mm, more preferably 0.08 to 0.5 mm, and most preferably 0.1 mm. If the coating thickness of the adhesive layer is less than 0.01 mm, the adhesion between the surface of the aluminum pipe and the resin layer composition may be reduced. Conversely, if the coating thickness of the adhesive layer is more than 1 mm, it is not possible to expect an effect of further improving adhesion.

(S5) Preheating step

The (S5) preheating step may be a step of preheating the aluminum pipe on which the adhesive layer is formed with a high frequency induction heater 80. In the step (S5), the aluminum pipe on which the adhesive layer is formed may be preheated while passing through the high frequency induction heater 80 to increase the surface temperature of the pipe. In the step (S5), the surface of the aluminum pipe is 100 to 200 °C, preferably 110 to 180 °C, more preferably 130 to 160 °C, most preferably 150 °C using a high frequency induction heater 80. Can be preheated to temperature. In the step (S5), the adhesive layer and the resin layer can be firmly adhered to each other at a relatively low temperature compared to the existing process. If the temperature is out of the above range, the adhesive strength between the adhesive layer and the resin layer may decrease.

(S6) resin layer formation step

The (S6) forming a resin layer may be a step of forming a resin layer having a thickness of 0.01 to 2 mm by coating a resin layer composition on the adhesive layer of the preheated aluminum pipe. The resin layer composition may be formed on the adhesive layer of the aluminum pipe to prevent corrosion of the pipe surface and improve the pressure resistance of the pipe. The resin layer composition may be one or more selected from the group consisting of polyamide, polyimide, polyacrylonitrile, polyethylene terephthalate, polytrimethylene terephthalate, polyether ketone, and polyethylene naphthalate. Preferably, it may be a polyamide resin. The polyamide resin may have a melting point of 180 to 300°C, preferably 200 to 280°C, more preferably 220 to 270°C, and most preferably 265°C. Since the polyamide resin has excellent heat resistance, it has an advantage that the resin is not denatured even in hot water of 100° C. or higher passing through an aluminum pipe. The resin layer may have a coating thickness of 0.01 to 2 mm, preferably 0.05 to 0.15 mm, more preferably 0.1 to 0.5 mm, and most preferably 0.18 mm. If the coating thickness of the resin layer is less than 0.01 mm, the corrosion resistance effect on the surface of the aluminum pipe may be insignificant, and the pressure resistance may decrease. Conversely, if the coating thickness of the resin layer is more than 2 mm, there may be a problem in that the manufacturing cost increases and the bendability of the aluminum pipe decreases.

On the other hand, the aluminum pipe of the multi-layered structure for the air conditioner of the present invention is an aluminum pipe having a scratch thickness of 0.05 ~ 0.3 ㎛ formed on the outer surface; An adhesive layer having a thickness of 0.01 to 1 mm formed on the surface of the aluminum pipe; And a resin layer having a thickness of 0.01 to 2 mm formed on the adhesive layer. The multi-layered aluminum pipe for the air conditioner may be manufactured by the above method.

2 is a side view of an aluminum pipe having a multi-layered structure for an air conditioner according to the present invention. 3 is a cross-sectional view of an aluminum pipe having a multi-layered structure for an air conditioner according to the present invention. 2 and 3, a scratch having a thickness of 0.05 to 0.3 µm on the surface of the aluminum pipe 110 drawn so that the inner diameter is 3 to 20 mm, the outer diameter is 6 to 22 mm, and the thickness is 0.4 to 2 mm ( 120) is formed. In addition, an adhesive layer 130 having a thickness of 0.01 to 1 mm is coated on the outer surface of the aluminum pipe 110 on which the scratches 120 are formed, and a resin layer 140 having a thickness of 0.01 to 2 mm is coated on the adhesive layer 130. It consists of a coated multi-layer structure. The scratch 120 and the adhesive layer 130 formed on the surface of the aluminum pipe 110 may serve to improve adhesion between the aluminum pipe 110 and the resin layer 140. The resin layer 140 may prevent surface corrosion of aluminum pipes and improve heat resistance, salt resistance resistance, and pressure resistance of the pipe. In addition, since the resin layer 140 has excellent heat resistance, the resin is not denatured even in hot water of 100° C. or higher passing through the multi-layered aluminum pipe 100.

As described above, the multi-layered aluminum pipe according to the present invention is lighter than the conventional metal pipe, has excellent workability, and is inexpensive, thereby reducing manufacturing cost. In addition, since the multi-layered aluminum pipe draws the aluminum pipe to an appropriate thickness, and the adhesive layer and the resin layer are uniformly coated on the surface of the pipe to an appropriate thickness, it can have excellent pressure resistance and flame resistance higher than the level allowed in an air conditioner. . In addition, by uniformly coating the surface of the pipe with a resin layer, it is possible to improve the corrosiveness of the aluminum pipe by protecting it from impurities such as moisture or salt.

The multi-layered aluminum pipe for the air conditioner according to the present invention is drawn with a drawing die and washed with a detergent containing a small amount of harmful components to improve roundness, prevent the pipe from being pressed, and at the same time improve stability problems for the human body and the environment. I can.

In addition, the aluminum pipe of the multi-layered structure for the air conditioner according to the present invention may have excellent pressure resistance and salt resistance resistance higher than the level allowed in the air conditioner by drawing the aluminum pipe to an appropriate thickness.

In addition, the aluminum pipe having a multilayer structure for an air conditioner according to the present invention may improve the adhesion between the aluminum pipe and the resin layer by physically scratching the surface of the drawn pipe and then uniformly coating the adhesive layer and the resin layer having an appropriate thickness in order. In addition, it has price competitiveness and is flexible, so it has excellent workability and can improve corrosion resistance and heat resistance.

The effects of the present invention are not limited to the effects mentioned above. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 is a block diagram of an apparatus for manufacturing a multi-layered aluminum pipe for an air conditioner according to the present invention.
2 is a side view of an aluminum pipe having a multi-layered structure for an air conditioner according to the present invention.
3 is a cross-sectional view of an aluminum pipe having a multi-layered structure for an air conditioner according to the present invention.

The above objects, other objects, features, and advantages of the present invention will be easily understood through the following preferred embodiments related to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed contents may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by the following examples.

Manufacturing example

An aluminum pipe made of aluminum was prepared. The aluminum pipe wound on the winding bobbin of 3000 to 16000 m by the unloading machine 1 was transferred to a straightener 2 and passed through the straightener 2 to straighten the coil-shaped aluminum pipe. Then, an aluminum pipe having an outer diameter, an inner diameter and a thickness as shown in Table 1 was drawn by passing through the drawing die machine 3. In order to check the pressure strength of the aluminum pipe thus manufactured, it was carried out in the same manner as in Table 4 below, and the results are shown in Table 1 below.

According to the results of Table 1, it was confirmed that in the case of Preparation Examples 1 to 5, the outer diameter, inner diameter, and thickness of the drawn aluminum pipes all satisfied all of the appropriate ranges, thereby achieving all the internal pressure strength of 20 MPa or more suitable for heating and cooling. .

On the other hand, in the case of Comparative Preparation Examples 1 and 2, the outer diameter and inner diameter of the aluminum pipe were satisfied within an appropriate range, but it was confirmed that the thickness was too thin, so that the internal pressure strength decreased. In addition, in the case of Comparative Preparation Examples 3 and 4, the material and thickness of the aluminum pipe did not satisfy the appropriate range, and thus the pressure resistance was significantly lower.

Examples 1 to 4 and Comparative Examples 1 to 5

[Material ingredients]

As a detergent composition, 65% by weight of dimethyl carbonate, 30% by weight of methylene chloride, and 5% by weight of chlorine dioxide were mixed. In addition, the adhesive composition is a bisphenol-based resin 18% by weight; 47% by weight toluene; And 35% by weight of methyl ethyl ketone were mixed. The resin layer composition used a polyamide resin.

[Manufacturing method]

An aluminum pipe having an inner diameter of 5.4 mm, an outer diameter of 6.4 mm, and a thickness of 1 mm prepared in Preparation Example 3 having the most excellent pressure resistance was prepared. After washing by spraying a cleaning agent onto the drawn aluminum pipe, it was dried with hot air at a temperature of 100° C. in a dryer (5). Then, a scratch was formed on the surface of the dried aluminum pipe to a depth as shown in Table 2 below using a scratch generator 6. Then, the adhesive composition was spray-sprayed with an adhesive applicator 7 to form an adhesive layer, and then preheated with a high frequency induction heater 8 so that the surface temperature of the aluminum pipe was 150°C. Then, the resin layer composition was added to the extrusion coating machine 9 to form a resin layer on the adhesive layer of the aluminum pipe, and then transferred to the cooler 10 and cooled with cooling water maintained at 15° C. to manufacture a multi-layered aluminum pipe. . Then, after passing through the take-up machine 11 at a maximum speed of 45 m/min, an aluminum pipe was wound on a 400-2000 m winding bobbin with a rewinder 12. At this time, the coating thickness of the adhesive layer was 0.1 mm, and the coating thickness of the resin layer was 0.18 mm. However, Comparative Example 1 did not perform the drawing process using the drawing die machine 3, and Comparative Example 4 did not perform the scratch process using the scratch generator 6. In addition, in Comparative Example 5, methylene chloride was used as a cleaning agent.

Examples 5-12 and Comparative Examples 6-11

It was carried out in the same manner as in Example 3, but the coating thickness of the adhesive layer and the resin layer were different, as shown in Table 3 below, to prepare an aluminum pipe having a multilayer structure.

Experimental Example 1: Evaluation of physical properties according to process conditions

In order to evaluate the physical properties of the multilayered aluminum pipes prepared in Examples 1 to 4 and Comparative Examples 1 to 5, it was measured by the experimental method shown in Table 4 below. The results are shown in Table 5 below.

According to the results of Table 5, it was confirmed that in the case of Examples 1 to 4, a value suitable for the required physical property level was indicated by performing all of the drawing, washing, and scratching processes. In particular, it was found that the difference in the depth of the scratch affects the pressure resistance, salt resistance resistance, and coating thickness error.

On the other hand, in the case of Comparative Examples 1 to 4, the drawing process was not performed, or the pressure resistance was greatly reduced depending on the depth of the scratch, and the error range of the coating thickness increased, and in the case of Comparative Example 4, corrosion occurred. Confirmed. In addition, in the case of Comparative Example 5, the physical property level generally satisfies the development target standard, but due to the use of methylene chloride as a cleaning agent, a large amount of components harmful to the health of workers were detected.

Experimental Example 2: Evaluation of physical properties according to coating thickness of adhesive layer and resin layer

In order to evaluate the physical properties of the multi-layered aluminum pipes prepared in Examples 5 to 12 and Comparative Examples 6 to 11, measurements were made in the same manner as in Table 3 above. The results are shown in Table 6 below.

According to the results of Table 6, in the case of Examples 5 to 12, both the pressure resistance and heat resistance were improved by coating the adhesive layer and the resin layer with an appropriate thickness, and corrosion resistance was excellent because no corrosion occurred. It was confirmed that the error of the coating thickness was also suitable for the required physical property level.

On the other hand, in the case of Comparative Example 6, due to the use of the existing one-component epoxy resin, the pressure resistance strength was low, corrosion occurred, and the roundness and coating thickness were not satisfied with the required physical property level. In addition, in Comparative Examples 7 and 8, it was confirmed that the thickness of the adhesive layer was too thin or too thick to satisfy the physical property level required by errors in pressure resistance, heat resistance, and coating thickness, and when the thickness of the adhesive layer was thin, corrosion occurred.

In the case of Comparative Examples 9 and 10, it was confirmed that the thickness of the resin layer was too thin or thick, so that the pressure resistance was not generally good, and the error in the coating thickness was largely widened. In addition, it was found that as the error range of the coating thickness increased, the heat resistance was significantly lowered.

In the case of Comparative Example 11, due to the use of polyethylene as the resin layer, it was found that the dimensional change of the multi-layered aluminum pipe occurred rapidly and the heat resistance was the lowest. Through this, it was found that depending on the coating thickness and composition of the adhesive layer and the resin layer, the effect on the pressure resistance strength, salt resistance resistance, heat resistance and coating thickness error of the multi-layered aluminum pipe was large.

1: unloading machine
2: straightener
3: drawing dice machine
4: washing machine
5: dryer
6: scratch generator
7: glue applicator
8: high frequency induction burner
9: extrusion coating machine
10: cooler
11: take-off
12: rewinding machine
100: multi-layered aluminum pipe
110: aluminum tubing
120: scratch
130: adhesive layer
140: resin layer

Claims (8)

Manufacturing the drawn aluminum pipe by inserting the aluminum pipe into the drawing die;
Washing the drawn aluminum pipe with a cleaning agent;
Forming a scratch having a thickness of 0.05 ~ 0.3 ㎛ on the surface of the cleaned aluminum pipe by a physical method of a scratch generator;
Forming an adhesive layer having a thickness of 0.01 to 1 mm by applying an adhesive composition on the surface of the scratched aluminum pipe;
Preheating the aluminum pipe on which the adhesive layer is formed with a high frequency induction heater; And
Forming a resin layer having a thickness of 0.01 to 2 mm by coating a resin layer composition on the adhesive layer of the preheated aluminum pipe;
Including,
The drawn aluminum pipe has an inner diameter of 3 to 20 mm, an outer diameter of 6 to 22 mm, and a thickness of 0.4 to 2 mm,
The adhesive composition comprises 12 to 20% by weight of a bisphenol-based resin; 40-50% by weight of toluene; And 30 to 40% by weight of methyl ethyl ketone; and
The cleaning agent is a method of manufacturing a multi-layered aluminum pipe for air conditioner, characterized in that consisting of 50 to 70% by weight of dimethyl carbonate, 25 to 40% by weight of methylene chloride, and 1 to 10% by weight of a chlorine stabilizer.
The method of claim 1,
The aluminum pipe is made of aluminum or an aluminum alloy.
The method of claim 2,
The aluminum alloy is an Al-Cu-based alloy (2000 series), Al-Mn-based alloy (3000 series), Al-Si-based alloy (4000 series), Al-Mg-based alloy (5000 series), Al-Mg-Si-based Alloy (6000 series), Al-Zn-Mg-based alloy (7000 series), and Al-Zn-Cu-based alloy (7000 series) is one or more selected from the group consisting of a method of manufacturing a multi-layered aluminum pipe for air conditioners.
delete delete The method of claim 1,
The resin layer composition is one or more selected from the group consisting of polyamide, polyimide, polyacrylonitrile, polyethylene terephthalate, polytrimethylene terephthalate, polyether ketone, and polyethylene naphthalate. Method of manufacturing.
delete delete

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