KR102053320B1 - Aluminum Surface Treatment Method for Polymer Bonding - Google Patents

Abstract

The present invention relates to an aluminum surface treatment method for bonding a silicon resin that can enhance the adhesion to the silicone resin by treating the surface of the aluminum using an etching or anodizing process using an acid or a base. The present invention comprises the steps of: (a) degreasing, etching, and immersing an aluminum substrate to pretreat; (b) Plasma Electrolytic Oxidation (PEO) by immersing the pretreated aluminum substrate in an electrolyte solution; And (c) bonding the silicon resin to the plasma electrooxidized aluminum.

Description

Aluminum Surface Treatment Method for Polymer Bonding

The present invention relates to an aluminum surface treatment method for bonding a silicone resin, and more particularly, a silicone resin which can improve adhesion to a silicone resin by treating an aluminum surface by using an etching or anodizing process using an acid or a base. The present invention relates to an aluminum surface treatment method for bonding.

In general, the bonding between aluminum and the polymer resin is usually performed using an adhesive. However, most of the adhesives used to bond the polymer resins are chemically melted and then bonded to the polymers, and since they are not applied to aluminum, physical adhesives are frequently used to bond the polymer resins to the aluminum.

Physical adhesive is an adhesive that is physically bonded between two materials by using friction force and van der Waals force, and can be used for various materials. Although physical damage is small, the adhesive strength is inferior to chemical adhesive. It has a disadvantage.

Therefore, in order to overcome the disadvantages of the physical adhesive, the adhesive is optimized according to each material and the use environment by changing the composition of the adhesive, but it has a disadvantage that it is difficult to provide the adhesive by type.

In order to improve this problem, a method of modifying the surface of aluminum is used. In the case of modifying the surface of aluminum, it is possible to increase the surface activity and frictional force of aluminum to obtain a high adhesive strength even if a general adhesive or a dissimilar material adhesive is used. There is no need to use adhesives, and the amount of adhesive used can be minimized.

Republic of Korea Patent Publication No. 10-2015-0098911 discloses a method for producing a dissimilar material assembly. In the present invention, the surface modifier and the medium gas are mixed and then pyrolyzed or photolyzed, and the surface of the solid material is modified using the pyrolyzed or photolyzed gas, but the surface is modified using the pyrolyzed gas under high temperature conditions. Therefore, it has a disadvantage that it can not be applied to heat-resistant polymer resin.

Republic of Korea Patent No. 10-1606567 discloses a method for producing an aluminum-polymer spherical conjugate and an aluminum-polymer resin assembly produced thereby. In the present invention, the aluminum base is improved by using acid etching and electrochemical coating to improve the adhesiveness with the polymer resin while ensuring the airtightness of the aluminum. However, since the polymer penetrates and adheres to the nanopores of aluminum, It has a disadvantage in that it is difficult to apply to a high viscosity polymer resin.

In order to solve the above problems, the present invention provides an aluminum surface treatment method for bonding a silicon resin that can enhance the adhesion with the silicone resin by treating the surface of the aluminum interposition using an etching or anodizing process using an acid or a base. To provide.

In order to solve the above problems, the present invention comprises the steps of: (a) degreasing, etching and immersing an aluminum substrate to pretreat; (b) Plasma Electrolytic Oxidation (PEO) by immersing the pretreated aluminum substrate in an electrolyte solution; And (c) bonding the silicon resin to the plasma electrooxidized aluminum.

The degreasing anhydrous sodium carbonate, sodium phosphate monobasic, potassium phosphate monobasic, ammonium monophosphate, dibasic sodium phosphate, dibasic potassium phosphate, diammonium phosphate, sodium triphosphate, tribasic potassium phosphate, potassium polyphosphate, Sodium polyphosphate, potassium pyrophosphate, sodium pyrophosphate, acid pyrophosphate, sodium hexametaphosphate, sodium stannate, potassium stannate, sodium nitrate, potassium nitrate, sodium citrate and potassium citrate It can be carried out with a degreasing agent.

The etching is at least one acid selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid and acetic acid or at least one selected from the group of sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, lithium hydroxide, aluminum hydroxide and ammonium hydroxide. Etching liquid containing the above base can be used.

In step (b), sodium silicate (Na ₂ SiO ₃ ) and potassium hydroxide (KOH) are used as electrolytes, and plasma electrooxidation is performed at a voltage of 100 to 300 V using a DC rectifier for 1 to 30 minutes at 0 to 50 ° C. Can be performed.

The aluminum may be aluminum 5052.

The etching and dismuting step (a) may be performed 2 to 10 times.

The etching may be alternately performed by etching with an acid and etching with a base.

The dispersing may be performed using sulfuric acid.

The bonding may be a melting or pressing to bond.

In the aluminum surface treatment method for bonding the silicon resin according to the present invention, the surface of the aluminum is etched and then anodized to increase the surface activity and frictional force, thereby enabling strong bonding with the silicone resin, thereby making the silicon resin and aluminum It can be widely used in the manufacture of household appliances, airplanes, automobiles and the like that must be used in combination.

Hereinafter, a preferred embodiment of the present invention will be described in detail. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted. Throughout the specification, when a part is said to "include" a certain component, it means that it may further include other components, not to exclude other components, unless otherwise stated.

In addition, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but between components It will be understood that may be "connected", "coupled" or "connected".

The present invention comprises the steps of: (a) degreasing, etching, and immersing an aluminum substrate to pretreat; (b) Plasma Electrolytic Oxidation (PEO) by immersing the pretreated aluminum substrate in an electrolyte solution; And (c) bonding the silicon resin to the plasma electrooxidized aluminum.

In the present invention, the surface-treated aluminum is capable of surface treatment of all aluminum that requires adhesion with polymer resins as well as aluminum that is conventionally used, but preferably 1085, 1080, 1070, 1050, 1100, 1200, 2014, 2017, 2219, 2024, 3033, 3203, 3004, 3014, 3005, 3105, 5005, 5052, 5652, 5154, 5254, 5082, 5182, 5083, 5086, 6160, 7075, 1N00, 1N30, 5N01 or 7N01, more preferably Surface treatment of 5052 is possible.

Step (a) is a step of pretreatment of the surface of the aluminum substrate is largely divided into a degreasing, etching and destomping step.

The degreasing step is a step of removing foreign substances and oil on the surface of the aluminum substrate, and any degreasing agent capable of removing foreign matter mill oil present on the surface of the aluminum can be used without limitation, but may be degreased using anhydrous sodium carbonate, first Sodium Phosphate, Potassium Phosphate, Monobasic Ammonium Phosphate, Dibasic Sodium Phosphate, Dibasic Potassium Phosphate, Dibasic Ammonium Phosphate, Tribasic Sodium Phosphate, Potassium Triphosphate, Potassium Polyphosphate, Sodium Polyphosphate, Potassium Pyrophosphate, Degreasing agent comprising at least one selected from the group consisting of sodium pyrophosphate, acidic pyrophosphate, sodium hexametaphosphate, sodium stannate, potassium stannate, sodium nitrate, potassium nitrate, sodium citrate and potassium citrate, more preferably sodium anhydride And degreasing agents comprising sodium triphosphate.

The degreasing agent may be used by mixing the anhydrous sodium carbonate in a ratio of 10 to 30 g / L, preferably 15 to 25 g / L, most preferably 20 g / L. At this time, if the anhydrous sodium carbonate is less than 10g / L concentration is low, it is difficult to expect degreasing effect, if it contains more than 30g / L, the anhydrous sodium carbonate is adsorbed on the aluminum surface may reduce the efficiency in subsequent processes have. In addition, the trisodium phosphate may include 3 ~ 10g / L preferably 5 ~ 7g / L, most preferably 6.6g / L. At this time, when the trisodium phosphate is included in less than 3g / L it is difficult to expect a degreasing effect because the concentration is lowered, when included in excess of 10g / L, the dispersing power of the degreasing agent may be stronger degreasing.

The etching is a step of chemically etching the surface of the aluminum, at least one acid selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid and acetic acid or sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, lithium hydroxide, It can be carried out with an etchant comprising at least one base selected from the group of aluminum hydroxide and ammonium hydroxide. In particular, when an acid is used as an etching solution, a reverse aqua regia mixed with nitric acid and hydrochloric acid may be used, and the nitric acid may be 200 to 500 g / L, preferably 300 to 350 g / L, and most preferably 330 g / L. It can be used in a concentration, and nitric acid and hydrochloric acid can be mixed in a ratio of 3: 1. At this time, if the nitric acid is included less than 200g / L, the etching does not occur, if it contains more than 500g / L may be excessively etched to damage the surface.

In addition, when using a base as an etching solution, sodium hydroxide can be used. The sodium hydroxide may be used by mixing at a ratio of 100 to 200 g / L, preferably 130 to 170 g / L and most preferably 150 g / L. If sodium hydroxide is used less than 100g / L does not occur etching, if containing more than 200g / L may be excessively etched to damage the surface.

The dismist may be performed using sulfuric acid to remove oxides generated on the aluminum surface by the etching. The sulfuric acid may be used in a mixture of 100 to 300 g / L, preferably 150 to 250 g / L, and most preferably 200 g / L. When the sulfuric acid is mixed at less than 100g / L, the dismuting effect is lowered, and when the sulfuric acid is mixed at more than 300g / L, there may be aluminum corrosion by the sulfur phase.

The etching and dismuting steps may be performed once after the degreasing step, but may be preferably performed 2 to 10 times and most preferably 2 times. If the repetition is more than 10 times, the surface may be excessively corroded, resulting in surface damage. In addition, in the case of repeating the etching and dismitting as described above, the etching using an acid and the etching using a base may be repeatedly performed alternately, and preferably, the base etching may be performed after the acid etching.

Each of the processes (degreasing, etching, dismuting) of step (a) may be performed at 40 to 80 ° C. for 10 seconds to 20 minutes, respectively. If performed below 40 ° C. or less than 10 seconds, the pretreatment effect of each step is inferior, and if performed above 80 ° C. or more than 20 minutes, there may be damage to the aluminum.

The step (b) is to plasma-oxidize the surface-treated aluminum substrate (Plasma Electrolytic Oxidation, PEO) using sodium silicate (Na ₂ SiO ₃ ) and potassium hydroxide (KOH) as an electrolyte, 0 ~ 50 ℃ At 1 to 30 minutes, plasma electrolytic oxidation can be performed using a DC rectifier at a voltage of 100 to 300 V. The plasma electrolytic oxidation is a process of oxidizing the surface of aluminum using a plasma to form an oxide film on the surface. As conventional anodizing oxidizes aluminum to produce a film, it is almost impossible to process wires or thin films, but the plasma In the case of electrolytic oxidation, since a silicate film is formed on the surface of the aluminum substrate and then oxidized to form a coating, it is possible to form a high-strength coating without damaging the aluminum substrate. In addition, as in anodizing, it is also possible to inject a dye into the oxide film so that the aluminum substrate has a constant color.

After the plasma electrolytic oxidation is completed, it is washed to remove the liquid and impurities remaining on the surface, dried and bonded with the silicone resin. The silicone resin can be used without limitation as long as the silicone resin can be bonded to the aluminum substrate. In addition, the bonding between the aluminum substrate and the silicone resin is preferably performed by melting the silicone resin and then bonding or simply applying pressure.

Hereinafter, the present invention will be described in detail through examples.

Example  One

1.2 cm, 8 cm, and 0.1 cm thick specimens made of aluminum 5052 were prepared and then pretreated by degreasing, etching, and immersing steps. The solution used in each pretreatment step is shown in Table 1 below.

Degreasing Anhydrous sodium carbonate (20 g / L),
Trisodium Phosphate (6.6g / L) etching Reverse hydrous nitric acid (330 g / l), hydrochloric acid (110 g / l) Dismute Sulfuric acid (200g / l)

After preparing 1 L of each solution, the aluminum specimens were immersed for 1 minute at a temperature of 60 ° C. for pretreatment.

The pretreated aluminum specimens were sodium silicate (Na ₂ SiO ₃ ) and potassium hydroxide (KOH) as the electrolyte, and plasma electrolytic oxidation was performed at a voltage of 200V using a DC rectifier at 5 ° C. for 5 minutes.

The plasma electrooxidized specimen was attached with the silicone resin to have a bonding area of 0.8 cm 2.

Example 2

Except for using sodium hydroxide (150g / L) as the etching solution in Example 1 was carried out in the same manner.

Example 3

In Example 1, after the dispersing step, sodium hydroxide (150 g / L) was additionally etched using the etching solution, and then the same procedure as in Example 1 was performed except that the dispersing step was further performed. .

Experimental Example

Bonding strength was measured using the specimens of Examples 1 to 3, and the results are shown in Table 2 below.

Example 1 Example 2 Example 3 One 6.2 7.0 12.5 2 8.6 11.2 12.0 3 9.7 9.2 14.4 4 6.7 11.7 9.0 5 5.3 7.2 9.5 6 7.1 9.3 12.9 7 7.0 10.8 13.7 8 5.7 11.2 9.5 9 6.5 9.8 15.0 10 7.4 8.1 11.8 11 5.2 9.6 9.7 12 8.7 7.7 13.5 13 9.7 9.6 13.3 14 5.5 11.7 13.4 15 9.6 8.1 12.6 16 5.5 8.5 12.5 17 8.2 9.8 8.9 18 5.8 12.0 8.0 19 6.9 7.9 7.6 20 7.6 10.4 12.0 Average 7.1 9.5 11.6

As a result of experiments using 20 specimens for each example, as shown in Table 2, the adhesive strength of Example 2 in the etching method using base was higher than that of Example 1, which was etched using acid on average. Example 3, etched with acid and then etched with base, was found to have the highest adhesive strength.

As described above in detail specific parts of the present invention, it will be apparent to those skilled in the art that these specific descriptions are merely preferred embodiments, and thus the scope of the present invention is not limited thereto. will be. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (9)

(a) pretreatment by degreasing, etching, and immersing the aluminum substrate
(b) plasma electrolytic oxidation (PEO) by immersing the pretreated aluminum substrate in an electrolyte solution; And
(c) bonding a silicone resin to the plasma electrooxidized aluminum;
In the aluminum surface treatment method for bonding a silicone resin comprising:
The etching is performed by using a mixed solution of nitric acid and hydrochloric acid, and then etching using an etching solution containing sodium hydroxide to aluminum surface bonding method for silicon resin bonding. The method of claim 1,
The degreasing anhydrous sodium carbonate, sodium phosphate monobasic, potassium phosphate monobasic, ammonium monophosphate, dibasic sodium phosphate, dibasic potassium phosphate, diammonium phosphate, sodium triphosphate, tribasic potassium phosphate, potassium polyphosphate, Sodium polyphosphate, potassium pyrophosphate, sodium pyrophosphate, acid pyrophosphate, sodium hexametaphosphate, sodium stannate, potassium stannate, sodium nitrate, potassium nitrate, sodium citrate and potassium citrate Aluminum surface treatment method performed with a degreasing agent. delete The method of claim 1,
In step (b), sodium silicate (Na ₂ SiO ₃ ) and potassium hydroxide (KOH) are used as electrolytes, and plasma electrooxidation is performed at a voltage of 100 to 300 V using a DC rectifier for 1 to 30 minutes at 0 to 50 ° C. Aluminum surface treatment method to perform. The method of claim 1
The aluminum is an aluminum surface treatment method of aluminum 5052. delete delete The method of claim 1,
The dispersing is aluminum surface treatment method using sulfuric acid. The method of claim 1,
The joining step is a step of melting or pressing to join the aluminum surface treatment method.