KR100982341B1 - Cleaning composition containing trichloroethylene or tetrachloroethylene - Google Patents

Abstract

The present invention provides a cleaning agent for effectively removing only the anisotropic conductive film (ACF) applied to the PCB without damaging other parts in order to reuse the PCB (Printed Circuit Board). In order to clean only the ACF, it is most preferable to apply an appropriate amount to the ACF site by increasing the viscosity so that the cleaner does not flow down, and then wiping it with a brush after a certain time. In the present invention, a cleaning composition suitable for this purpose is prepared by mixing trichloroethylene or tetrachloroethylene which is effective in removing ACF, and adding additives such as thickener, methanol, and surfactant thereto.

Anisotropic conductive film, cleaner, thickener, surfactant, PCB

Description

Cleaning composition containing trichloroethylene or tetrachloroethylene

The present invention relates to a cleaning composition for removing an anisotropic conductive film on a printed circuit board. The cleaning composition of the present invention for removing the anisotropic conductive film contains trichloroethylene or tetrachloroethylene as a solvent.

The present invention relates to a method for reusing and recycling a defective part of a PCB component generated when manufacturing an LCD panel, and to provide a method of recycling only by removing an anisotropic conductive film (ACF) coating site without hurting other parts of the PCB. It is. This method recovers waste home appliances or defective parts during the manufacturing process and re-commercializes them to new product level, compared to the recycling method of pulverizing and extracting precious metal components. It is economical and eco-friendly because its efficiency is very high in terms of raw materials, labor, and energy compared to recycling.

Currently, the LCD module consists of three parts: a panel, a printed circuit board (PCB), and a chassis. Among them, PCB manufacturing technology is very expensive because it uses very complicated and expensive raw materials. PCB is a thin plate on which electrical components such as integrated circuit resistors or switches are soldered, and is a circuit used in most computers. It is a problem by discharging pollutants and wastes that are harmful to the environment during the manufacturing process. PCB manufacturers must also comply with stringent environmental policies on waste management in the European Union, such as the Waste from Electrical and Electronic Equipment Directive (WEEE). In addition, as price competition in the semiconductor and display sectors is intensifying and environmental regulations are tightened, the demand for recycling of raw materials and waste materials, which are expensive and cause environmental pollution, is increasing. Therefore, the recycling business can provide both a justification and price competitiveness. Currently, the amount of waste PCB generated in LCD lines is about 10%, so recycling and recycling them is gaining economic interest.

ACF is made by dispersing electrically conductive microparticles uniformly in an organic material having insulation and in the form of a film. It has electrical conductivity in the thickness direction of the film and electrical anisotropy with insulation in the plane direction. It is a polymer adhesive film having both adhesiveness and adhesiveness at the same time. In other words, ACF is a double-sided tape in which a heat-hardened adhesive and a fine conductive ball are mixed in it. When high-temperature pressure is applied, the conductive ball is destroyed when the conductive ball of the pad of the circuit pattern comes into contact. The ball is energized between the pads, and the remaining adhesive is filled / cured on the concave-convex surface other than the pad portion to bond to each other. Most of the defects in the PCB manufacturing process are due to ACF, so if you remove the ACF well without damaging other parts, you can recycle the PCB.

Most existing techniques for removing ACF consist of heating the ACF-coated area or mechanically wiping it with a volatile organic solvent. Currently, the most effective cleaning agent uses methylene chloride as its main ingredient, which belongs to 37 VOCs announced by the Ministry of Environment, and it is increasingly regulated due to its high volatility and toxicity. There is an urgent need for cleaning agents.

The present invention is to provide a cleaning composition that can replace methylene chloride, a solvent mainly used as a cleaning agent for removing ACF on a printed circuit board.

In the present invention, ACF to replace the methylene chloride by investigating the cleaning agent component having a high molecular weight and low volatility while having a similar chemical structure and excellent cleaning effect as a component that can replace methylene chloride which is a main component of the conventionally used detergent It has been found that trichloroethylene or tetrachloroethylene compounds can be used as the cleaning agent for removal.

According to the present invention, a cleaning composition is provided using trichloroethylene or tetrachloroethylene compound as a solvent for removing ACF replacing methylene chloride.

The present invention is a cleaning composition for removing an anisotropic conductive film of a printed circuit board (PCB), 80 to 98% by weight of at least one solvent selected from the group consisting of trichloroethylene and tetrachloroethylene, and xanthan gum (Xanthan gum) A cleaning composition comprising 2 to 20% by weight of one or more thickeners selected from the group consisting of cellulose, ethylcellulose, liquid paraffin, paraffin wax, and gelatin.

The cleaning composition of the present invention may further include a surfactant in an amount of 20% by weight or less based on the total weight of the composition.

 The cleaning composition of the present invention also comprises one or more second solvents selected from the group consisting of methanol, ethylene carbonate, acetone, acetonitrile, 2-ethoxyethyl-ether, DGME and xylene, based on the total weight of the cleaning composition The phosphorus diluent may be further included in an amount of up to 50%.

In the cleaning composition of the present invention, the solvent is contained in an amount of 80 to 98% by weight, and the thickener is contained in an amount of 2 to 20% by weight. The content range is used to mix the solvent and the thickener in the above-described range in order to increase the viscosity and to suppress the volatility since the solvent is used alone as a cleaning composition damages parts other than ACF.

As a thickener contained in the cleaning composition of the present invention, xanthan gum can be obtained from Carl Roth GmbH under the trade name Xanthan, and cellulose, ethyl cellulose, liquid paraffin, paraffin wax and gelatin can be obtained from Daejung Gold Co., Ltd., respectively. have.

 Surfactant optionally added to the cleaning composition of the present invention is polyoxyethylene alkyl aryl ether (Polyoxyethylene alkyl aryl ether (IC: LA-5, LA-7)), polyoxyethylene alkyl ether (Polyoxyethylene alkyl ether, IC Chemical (Trade Name: NP-8, NP-10)), Cetyl Dimethyl Amine, Aekyung Fine Chemical (trade name: ASCO CTAC), EQ (C16-18 unsaturated fatty acid carbon number C10-20, Aekyung Fine Chemical ( Product Name: ASCO EQ 85,90)), Sodium Laurate Sulphate (SODIUM LAURETH SULFATE, Aekyung Fine Chemicals, ASCO SLES) (Aekyung Fine Chemical (trade name: ASCO AOS)).

As a method of using the cleaning composition of the present invention, the simplest method is to put the ACF coating part of the PCB into the cleaning agent for a predetermined time and inflate the ACF and then wash it with a brush. However, this approach can damage other parts of the PCB in addition to the ACF that you want to remove, making it impossible to recycle. In order to compensate for this, a variety of methods have been devised such as limited spraying or weak heating to the ACF area as a nozzle type, but each has advantages and disadvantages. In order to effectively remove the ACF, it is necessary to contact the cleaning agent for about 5 to 10 min. In other words, in order to remove only ACF without damaging other parts, it is most preferable to apply an appropriate amount to the ACF part by increasing the viscosity so that the detergent does not flow down, and then wiping with a brush after a certain time. In the present invention, a cleaning agent suitable for this purpose was prepared by mixing trichloroethylene or tetrachloroethylene, which is effective for removing ACF, as a main ingredient, and additives of a thickener, methanol, and any surfactant.

Example

Experiment method

Trichloroethylene or tetrachloroethylene was selected as the component with the highest ACF cleaning power. Various organic solvents were used.In order to increase the viscosity, ethyl cellulose, carbomer, paraffin wax, cellulose, gelatin, or xantane (xanthan) was used, and the washing effect was examined by mixing the surfactant in various compositions to increase the viscosity and increase the mixing effect. The mixture was stirred at 1000 RPM for 1 hour. The detergent thus prepared was applied to an ACF-coated portion in an appropriate amount, and after 5 minutes, the first washing was performed using an electric brush washing machine, followed by applying acetone with a second washing agent, followed by washing with an electric washing machine.

In order to quantitatively evaluate the performance of the cleaning agent, a PCB panel was cut to a constant length of about 5 cm and subjected to the ACF cleaning experiment. The width to which the ACF is applied is approximately 3 mm. The whole was divided into 5 equal parts by 1 cm, and the washing condition was visually inspected for each part. The same experiment was repeated 10 times or more to obtain an average value. The visual inspection result quantified the cleaning status based on the following criteria.

Table 1. Criteria for Quantifying ACF Wash

0 ACF almost completely removed One Very little residue left 2 ACF partially remains 3 ACF remains in large chunks 4 There is a lot of ACF left overall 5 Almost Flushed ACF

Reference Example  One

Figure 1 shows the results of comparing the ACF washing performance using a variety of organic solvents. Figure 1 is an experiment to confirm only the ACF cleaning effect, because no other additives were added to the liquid solvent in the beaker and put the ACF coating area of the PCB in the liquid for 5 min, and shows the result of washing immediately with a brush . The same experiment was repeated 10 times or more to summarize the results of quantifying the washing state based on the criteria shown in Table 1.

Table 2. Quantitative Comparison of ACF Washing Performance by Various Organic Solvents

Methyl ethyl ketone 4.3 4.1 4.1 3.2 1.3 Ethylene carbonate 2.2 3.2 3.1 1.1 1.4 Acetone 4.5 5.0 5.0 5.0 5.0 Acetonitrile 5.0 5.0 5.0 5.0 5.0 2-ethoxyethyl-ether 4.2 4.1 4.1 4.1 4.3 DGME (dimethylene glycol monoethyl ether) 5.0 4.4 4.3 5.0 4.5 Xylene 4.2 4.1 4.3 5.0 5.0 Tetrachloroethylene 0.2 0.0 0.0 0.0 0.1 Trichloroethylene 0.1 0.0 0.0 0.0 0.1

As shown in Table 2, most common organic solvents had little effect on ACF cleaning, and although ethylene carbonate showed some ACF cleaning performance, it had to be dissolved at 40 ℃ or higher because it was solid at room temperature. In addition, it is unsuitable as a detergent. However, in the case of tetrachloroethylene and trichloroethylene it can be seen that the ACF cleaning effect is very excellent. Since the PCB panel was cut to 5 cm in length, there were some ACFs left at both ends, but it can be supplemented by maintaining the proper viscosity with additives.

Reference Example 2

Table 3 shows the results of the quantitative comparison of ACF washing performance when trichloroethylene had a solvent containing little ACF washing performance and very inexpensive methanol. When only about 10% of trichloroethylene was contained, the result showed the ACF washing effect to some extent, and when about 50% of trichloroethylene was contained, more than 90% of ACF could be removed. Therefore, it is thought that the amount of trichloroethylene or tetrachloroethylene can be reduced by more than 50% by mixing appropriate additives.

Table 3. ACF cleaning performance using mixed solvent of trichloroethylene and methanol

Trichloroethylene content 0% 5.0 5.0 5.0 5.0 5.0 Trichloroethylene content 5% 4.1 3.5 3.4 3.4 3.5 Trichloroethylene content 10% 2.8 2.8 2.3 2.3 3.0 Trichloroethylene content 50% 1.5 1.3 0.8 1.3 1.5

It should be called at room temperature for more than 5 minutes after applying the cleaner to the ACF coated area. If trichloroethylene or tetrachloroethylene is used alone, it may damage other parts of the ACF. In order to improve this, additives for increasing viscosity and suppressing volatility are needed.

Example 1

Based on trichloroethylene or tetrachloroethylene, as mentioned above, to increase the viscosity, as a thickener, ethyl cellulose, carbomer, paraffin wax, cellulose, gelatin, xanthan, etc. were investigated. In order to increase the viscosity and increase the mixing effect, the cleaning effect was examined by mixing the surfactant in various compositions. The mixture was stirred at 1000 RPM for 1 hour. The detergent thus prepared was applied to an ACF-coated portion in an appropriate amount, and after 5 minutes, the first washing was performed using an electric brush washing machine, followed by applying acetone with a second washing agent, followed by washing with an electric washing machine.

Figure 2 shows the results of the cleaning composition prepared by mixing the existing cleaning agent and trichloroethylene 950g, ethyl cellulose 30g, methanol 20g according to the present invention as a photograph and the state of the wash quantified according to the evaluation criteria of Table 1. Compared with conventional methylene chloride-based cleaners known to have the highest cleaning power, the results are almost insignificant, and the surface state after washing was rather smooth and glossy.

Cleaning compositions were prepared in the amounts shown in Table 4 in a similar manner as described above to evaluate ACF cleaning performance.

Table 4. Preparation of Cleaning Composition

washing
Composition Trichloroethylene Tetrachloroethylene Thickener Secondary solvent Surfactants One 900 g - 50 g (tantan) 50 g (ethylene carbonate) - 2 850 g - 70 g (tantan) 80 g
(Methanol) - 3 800 g - 80 g (tantan) 120 g
(Acetone) 50 g
(Cetyldimethylamine) 4 - 900 g 70 g (tantan) 30 g
(DGME) - 5 800 g 80 g (tantan) 100 g (ethylene carbonate) 20 g (sodium laures sulfate) 6 850 g 30 g (ethyl cellulose) 120 g
(Methanol) - 7 980 g - 20 g (ethyl cellulose) - - 8 - 850 g 30 g (ethyl cellulose) 120 g
(Methanol) - 9 - 950 g 30 g (ethyl cellulose) 20 g
(DGME) - 10 750 g - 100 g
(Cellulose) 100 g
(DGME) 50 g (polyoxyethylene alkyl ether) 11 800 g - 150 g
(Cellulose) - 50 g (polyoxyethylene alkyl ether) 12 800 g - 200 g
(Cellulose) - - 13 800 g 150 g
(Cellulose) - 50 g (polyoxyethylene alkyl ether) 14 750 g - 30 g (gelatin) 120g (ethylene carbonate)  100 g (polyoxyethylene alkyl aryl ether) 15 800 g - 30 g (gelatin) 120g (ethylene carbonate)  50 g (polyoxyethylene alkyl aryl ether) 16 900 g - 50 g (gelatin) -  50 g (polyoxyethylene alkyl aryl ether) 17 900 g - 50 g (gelatin) -  50 g (sodium olefin sulfonate) 18 - 800 g 50 g (gelatin) 100 g (ethylene carbonate) 50 g (polyoxyethylene alkyl aryl ether) 19 - 900 g 50 g (gelatin) - 50 g (polyoxyethylene alkyl aryl ether) 20 - 900 g 50 g (gelatin) - 50 g (polyoxyethylene alkyl ether)

As a result of confirming the cleaning performance by preparing a cleaning composition having the components and contents shown in Table 4, the same or similar results as in FIG.

The cleaning compositions 7 and 12 according to the present invention are prepared by adding only thickeners, and are applied to ACF and exhibit a viscosity suitable for inflating for a predetermined time and are excellent in ACF cleaning performance. However, when the proper time (within about 10 minutes) is exceeded after applying the cleaner, a thin film is formed on the surface or residues remain after washing.

In the cleaning compositions 3, 5, 10, 11 and 13-20 prepared by further mixing the surfactants, there was an effect of promoting uniform mixing of the thickener, and the viscosity of the cleaning composition was increased and evaporation was suppressed. It was easy to, and there was no significant effect on the ACF cleaning performance.

In the cleaning compositions 1-6, 8-10, 14, 15, and 18 to which the second solvent, which is a diluent, was added, there was a slight difference in viscosity, volatility, and ease of mixing, depending on the added solvent. There was no. When DGME is added as a second solvent (detergent compositions 4, 9, and 10), there is a odor peculiar to DGME, and since ethylene carbonate (detergent compositions 1, 5, 14, 15, and 18) is solid at room temperature, Although it is troublesome to mix after heating and melting above 40 ° C., there are side effects such as viscosity improvement and volatility suppression.

1 is a photograph comparing the ACF washing performance using various organic solvents.

Figure 2 is a photograph comparing the washing performance of the methylene chloride-based conventional cleaning agent and the cleaning composition of the present invention containing trichloroethylene as a main component.

Claims (5)

A cleaning composition for removing an anisotropic conductive film of a printed circuit board (PCB), comprising: 80 to 98% by weight of at least one solvent selected from the group consisting of trichloroethylene and tetrachloroethylene, and xanthan gum cellulose And 2-20 wt% of one or more thickeners selected from the group consisting of ethylcellulose, liquid paraffin, paraffin wax, and gelatin. The cleaning composition of claim 1, further comprising a surfactant in an amount of up to 20% by weight, based on the total weight of the cleaning composition. The cleaning composition according to claim 2, wherein the surfactant is at least one surfactant selected from the group consisting of polyoxyethylene alkylaryl ether, polyoxyethylene alkyl ether, cetyldimethylamine, sodium laureth sulfate and sodium alphaolefin sulfonate. The method of claim 1, wherein the solvent is at least one second solvent selected from the group consisting of methanol, ethylene carbonate, acetone, acetonitrile, 2-ethoxyethyl-ether, DGME and xylene, based on the total weight of the cleaning composition. A cleaning composition further comprising a diluent in an amount up to 50% by weight. The cleaning composition of claim 4, further comprising a surfactant in an amount of up to 20% by weight, based on the total weight of the composition.

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