JPH04244280A - Washing treatment of rosin type solder flux using non-halogen type rosin type solder flux detergent - Google Patents

Abstract

PURPOSE:To omit a heating and drying process and a waste water treatment process both of which are derived from the rinsing process essential in a case using a non-halogen type rosin type solder flux detergent, to use a conventional washing apparatus as it is and to keep the washing properties and environmental characteristics which are advantages of said detergent. CONSTITUTION:A non-halogen type rosin type solder flux detergent is brought into contact with an object to be treated such as a substrate to which a rosin flux detergent is bonded to wash said object and, subsequently, a fluorocarbon is brought into contact with the substrate to remove the residual detergent bonded to the substrate. In this washing treatment process, the heating and drying process and waste water treatment process derived from a conventional rinsing process can be omitted while the washing properties and environmental characteristics being the advantages of the non-halogen type rosin type flux detergent are kept.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning flux using a non-halogen rosin solder flux cleaning agent. More specifically, the present invention relates to a novel cleaning method for rosin-based solder flux that uses the cleaning agent and a specific rinsing agent and has excellent cleaning properties and can omit a heating drying step and a wastewater treatment step.

0002

2. Description of the Related Art Rosin-based solder flux is used in the production of modules such as printed circuit boards and printed wiring boards. The purpose of soldering is generally to increase the adhesive strength between the board and the input/output pins, and to prevent oxidation of the contacts and maintain conductivity.In order to make the soldering process more effective, rosin-based Solder flux is used. After soldering, a cleaning agent is used to selectively and completely remove flux from the board surface. That is, if the cleaning of the flux is insufficient, there is a disadvantage that the residual flux causes circuit corrosion, or the electrical insulation of the substrate surface decreases, which ultimately leads to circuit damage. Therefore, the above-mentioned disadvantages are overcome by using detergents to remove the residual flux, especially the activator components contained therein.

Conventionally, halogenated hydrocarbon solvents such as so-called chlorofluorocarbons such as trichlorethylene and trichlorotrifluoroethane have been used as cleaning agents for rosin-based solder flux. Regarding the halogen-based cleaning agent,
Although they themselves have the advantage of being nonflammable and having excellent drying properties, due to environmental pollution problems such as ozone layer depletion, their use is being strictly regulated. The development of cleaning agents has become an urgent need.

In response to this situation, various non-halogen solder flux cleaning agents, such as saponification type, hydrocarbon solvent type, and higher alcohol type, have recently been developed and are being put on the market. There are advantages and disadvantages compared to . For example, in the case of alkaline saponification type, there is no problem of flammability because it is an aqueous solution type, but when cleaning, it is necessary to contact the liquid for a long time under heating, resulting in low cleaning efficiency. There are disadvantages such as concerns about corrosion of the parts. On the other hand, in the case of cleaning agents such as hydrocarbon solvent type and higher alcohol type, no one has yet been found that completely satisfies all required performance such as cleaning power, toxicity, odor, and flammability. It is.

By the way, the inventors of the present invention have made extensive studies to solve the above problem, and have found that a mixture containing a specific glycol ether compound, a nonionic surfactant, and water as essential components, and a mixture containing a specific glycol ether compound, a nonionic surfactant, and water as essential components, It has been found that the above problems can be solved when a mixture containing a polyoxyalkylene phosphate surfactant as an essential component is used. That is, we have completed an invention related to a non-halogen solder flux cleaning agent that has excellent cleaning power and is substantially satisfactory in terms of environmental characteristics, odor, flammability, etc., as well as a cleaning method using the cleaning agent, and have already obtained a patent. I filed an application.

[0006] However, all of these various fluorocarbon alternative cleaning agents require a water rinsing step. Although the water rinsing process yields objects to be cleaned with excellent cleanliness, there is a problem in that it is difficult to use existing cleaning equipment as is. That is, in addition to the water rinsing process, a heating drying process and a waste water treatment process are required, which necessitates a change in the specifications of the cleaning device.

[0007]

[Problems to be Solved by the Invention] The present invention maintains a high level of cleaning performance when cleaning flux using a non-halogen-based rosin-based solder flux cleaning agent, which is a new cleaning agent that replaces fluorocarbons. Moreover, it is an object of the present invention to provide a cleaning processing method that can use conventional cleaning equipment as is. In other words, this is a new cleaning method that is based on the use of a non-halogen rosin solder flux cleaning agent, and which can omit the heating drying process and waste water treatment process for removing adhered water resulting from the water rinsing operation. The purpose is to provide

[0008]

[Means for Solving the Problem] As a result of intensive studies to achieve the above object, the present inventors have developed a non-halogen rosin-based solder flux cleaning agent, which is a new cleaning agent that replaces fluorocarbons, and a specific rinsing agent. The present inventors have discovered that all of the above problems can be solved by applying a cleaning and rinsing method that uses the above methods in combination, and have completed the present invention.

That is, in the present invention, a non-halogenated flux cleaning agent is brought into contact with a workpiece to which rosin-based solder flux has adhered in a cleaning tank to wash and remove the flux from the workpiece, and then the flux is removed in a rinsing tank. The present invention relates to a flux cleaning method using a non-halogen rosin solder flux cleaning agent, which is characterized by bringing fluorocarbon into contact with an object to be treated.

In the present invention, the cleaning agent for the rosin solder flux is not particularly limited, and conventionally known non-halogen cleaning agents can be used. For example, various examples include mixtures of hydrocarbon solvents such as limonene, tetralin, decane, and dodecane and various surfactants, mixtures of glycol ether compounds and surfactants, and mixtures of these mixtures and water. Preferred compositions include, for example, a mixture of a glycol ether compound, a nonionic surfactant and water, or a glycol ether compound,
This includes non-flammable and non-halogen cleaning agents consisting of a nonionic surfactant, a polyoxyalkylene phosphate surfactant, and water.

[0011] Hereinafter, the components of the above-mentioned preferred cleaning agent will be explained in detail as representative examples. Examples of the glycol ether compounds represented by the general formula (1) include diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol monopropyl ether, diethylene glycol dipropyl ether, and diethylene glycol methyl. Propyl ether, diethylene glycol ethyl propyl ether, diethylene glycol monobutyl ether,
Diethylene glycol dibutyl ether, diethylene glycol methyl butyl ether, diethylene glycol ethyl butyl ether, diethylene glycol propyl butyl ether, diethylene glycol monopentyl ether, diethylene glycol dipentyl ether, diethylene glycol methyl pentyl ether, diethylene glycol ethyl pentyl ether, diethylene glycol propyl pentyl ether, diethylene glycol butyl pentyl ether; - or tetraethylene glycol ethers; di-, tri-, or tetrapropylene glycol ethers corresponding to these can be exemplified. These compounds can be used alone or in an appropriate combination of two or more.

Among the components of the preferred detergent, the nonionic surfactant is not particularly limited as long as its ionicity is nonionic, and various known surfactants may be used. A specific example is polyoxyethylene alkyl (C6
<) Polyethylene glycol ether type nonionic surfactants such as ether, polyoxyethylene phenol ether, and polyoxyethylene alkyl phenol ether; Polyethylene glycol ester type nonionic surfactants such as polyethylene glycol monoester and polyethylene glycol diester; Higher aliphatic Ethylene oxide adducts of amines; ethylene oxide adducts of fatty acid amides; polyhydric alcohol-type nonionic surfactants such as sorbitan fatty acid esters and sucrose fatty acid esters; fatty acid alkanolamides, etc., and polyoxypropylene-based products corresponding to these. Examples include nonionic surfactants and polyoxyethylene polyoxypropylene copolymer type nonionic surfactants. These nonionic surfactants can be used alone or in combination of two or more. Among these, polyethylene glycol ether type nonionic surfactants are preferred from the viewpoint of detergency, and those represented by the following general formula (2) are more preferred.

[0013]

[Case 2]

[0014] As the phosphate ester type anionic surfactant, various known phosphate ester type anionic surfactants can be used without limitation, but those represented by the following general formula (3) are preferable. do.

[0015]

It is a surfactant represented by the following formula or a salt thereof. Examples of such salts include metal salts such as sodium salts and potassium salts, ammonium salts, and alkanolamine salts. There are various commercially available phosphoric acid ester-based anionic surfactants represented by the general formula (3) or their salts, such as the "Plysurf" series manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Nippon Nyukazai, etc. "N-1000F" manufactured by Co., Ltd.
Examples include "CP", "RA-574", and "RA-579".

The proportions of the glycol ether compound, nonionic surfactant, and polyoxyphosphate ester surfactant used are not particularly limited, but are usually about 10 to 95% by weight: about 5 to 90% by weight. :
About 0.1 to 90% by weight, preferably 50% by weight
~90% by weight: 10-60% by weight: 0.5
It is about 60% by weight.

[0017] In the present invention, various known fluorocarbons can be used without limitation as the fluorocarbon rinsing agent, such as 2,2,3,3-tetrafluoro-
1-propanol, perfluoro-2-methylpentane, perfluorocyclohexane, perfluoromethylcyclohexane, perfluoro-1,3-dimethylcyclohexane, 2,2,3,3,4,4,5,5-octafluoro- 1-pentanol, 1,1,1,3,3,3-
Hexafluoro-2-propanol, 2,2,3,3,
Examples include 4,4-hexafluorobutanol and 5-fluorinated propanol (pentafluoropropyl alcohol). Among these, 5-
Fluorinated propanol is best. In addition, as a commercial product of 5-fluorinated propanol, "Pefol TM5P" manufactured by Daikin Industries, Ltd. can be exemplified.

The following means can be employed to bring the cleaning agent of the present invention into contact with the rosin flux on the substrate. for example,
Glycol ether compounds, nonionic surfactants,
When using a cleaning agent comprising a polyoxyphosphate surfactant, the cleaning agent is adjusted as it is or dissolved in water so that the concentration of the active ingredient is usually about 100 to 10% by weight. A method of directly immersing the treated agent, for example, a substrate, in the thus obtained aqueous solution or the active ingredient itself for cleaning, a method of flushing the aqueous solution using a spray device, a method of brushing by mechanical means, and an ultrasonic cleaning method. It is possible to appropriately select and employ various methods such as the above method.

Conditions for applying the cleaning agent in the present invention may be appropriately selected depending on the concentration of the active ingredient in the cleaning agent, the usage ratio of the ingredient, the type of flux to be removed, etc. The cleaning agent is contacted with the flux at a temperature and time effective to wash away the flux. The temperature during use of the cleaning agent is about room temperature to about 80°C, and usually preferably about 50 to 70°C. When removing solder flux on a substrate by a dipping method at a temperature of about 60° C., for example, the solder flux can be removed satisfactorily by immersing the substrate with solder flux in the cleaning agent of the present invention for about 1 to 5 minutes. Can be done.

The substrate from which the flux has been removed in this way is
Any remaining cleaning agent is then completely removed by contacting it with a fluorocarbon rinsing agent. The conditions for using the rinsing agent include at least one of the following methods: directly immersing the substrate, flashing the rinsing agent using a spray device, irradiating ultrasonic waves, and using vapor from the rinsing agent. By adopting two methods, rinsing treatment can be performed effectively. The temperature when using the rinsing agent is from about room temperature to about 80°C, and if a method such as dipping or spraying is used, it is preferably from room temperature to about 50°C. For example, if rinsing is performed by dipping at a temperature of about 40°C, the substrate is generally rinsed at 30°C.
If immersed for about 2 to 3 minutes, the rinsing process can be performed satisfactorily. For rinsing, in addition to using a single rinsing tank, multiple rinsing tanks can be used, and it is sufficient to determine the specifications as appropriate, taking into account processing costs, processing time, rinsing solution life, etc. In addition, it is also possible to perform washing with water before using the rinsing agent, and then drain the water with the rinsing agent.

[0021]

[Effect of the invention] Cleaned using a non-halogen cleaning agent,
The cleanliness of the substrate that is then rinsed with fluorocarbon is extremely high, and the problem of ozone layer depletion is also eliminated. In addition, due to the volatility of the rinsing agent, there is no need for a heating and drying process, and various effects can be achieved, such as making it possible to omit or significantly reduce the burden of wastewater treatment.

[0022]

[Examples] The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples.

Reference Example 1 65 parts by weight of diethylene glycol dimethyl ether and a polyethylene glycol alkyl ether type nonionic surfactant (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name "Neugen ET-135", in general formula (2), R4 is the number of carbon atoms 12-14 branched alkyl group, m is 9)
Cleaning agent A was prepared by mixing 20 parts by weight and 15 parts by weight of pure water.

Reference Examples 2 to 7 Evaluations were carried out in the same manner as in Reference Example 1, except that the composition of the cleaning agent was changed as shown in Table 1.

In Table 1, DEGDME: diethylene glycol dimethyl ether, DEGMBE: diethylene glycol monobutyl ether, DEGDEE: diethylene glycol diethyl ether, POEAPE: phosphate ester-based anionic surfactant, and in the general formula (3), R
5 is a straight-chain alkyl group having 12 carbon atoms, n is 10, and X is a mixture of a hydroxyl group and general formula (4) (R6 is a straight-chain alkyl group having 12 carbon atoms).

Example 1 A rosin-based flux (manufactured by LONCO, trade name: "Resin Fl") was applied to the entire surface of a printed wiring board (copper-clad laminate).
ux #77-25'') was applied, dried at 130°C for 2 minutes, and solder flowed at 260°C for 5 seconds to prepare a test board. This substrate was immersed in the above-mentioned cleaning agent A at room temperature to clean it, and then 5-fluorinated propanol (hereinafter abbreviated as 5FP; manufactured by Daikin Industries, Ltd., product name "Pefol T") was washed at room temperature.
M5P") for about 30 seconds and rinsed once. Further, this was left to dry at room temperature, and the degree of flux removal was visually judged based on the following criteria. The results are shown in Table 2. ○ Can be removed well △ Slightly remaining × Significantly remaining Next, the above board was washed with an Omegameter 600SE
The cleanliness (residual ion concentration) of the substrate was measured using KO Co., Ltd. (trade name). The results are shown in Table 2.

Examples 2 to 9 Cleaning and rinsing treatments were carried out in the same manner as in Example 1, except that the type of cleaning agent was changed to those shown in Table 2, and the degree of flux removal was evaluated. The results are shown in Table 2.

Examples 10 to 16 Evaluations were carried out in the same manner as in Example 1, except that the type of cleaning agent was changed to that shown in Table 2, and the 5FP rinsing process was changed from once to twice. The results are in Table 2
Shown below.

Examples 17 to 23 In Example 1, the type of cleaning agent was changed to those shown in Table 2, and the rinsing process was performed using water first and then 5FP.
The evaluation was carried out in the same manner except that The results are shown in Table 2.

Comparative Example 1 In Example 2, a comparative evaluation was conducted when rinsing was performed with water. The results are shown in Table 2.

Comparative Example 2 Comparative evaluation was carried out in the same manner as in Comparative Example 1, except that the type of cleaning agent was changed to those shown in Table 2. The results are shown in Table 2.

[0032]

[Table 2]

Claims (4)

[Claims] Claim 1: A non-halogen flux cleaning agent is brought into contact with a workpiece to which rosin-based solder flux has adhered in a cleaning tank to wash and remove the flux from the workpiece, and then fluorocarbon is coated in a rinse tank. A method for cleaning flux using a halogen-free rosin-based solder flux cleaning agent that is brought into contact with an object to be treated. 2. The non-halogen rosin solder flux cleaning agent comprises at least one glycol ether compound represented by the general formula (1): [Chemical 1], a nonionic surfactant, and optionally The cleaning method according to claim 1, which is a non-flammable and non-halogen cleaning agent containing a mixture of water and/or a polyoxyalkylene phosphate surfactant as an active ingredient. 3. The cleaning method according to claim 1, wherein the rinsing agent is a non-flammable fluorocarbon. 4. The cleaning method according to claim 3, wherein the rinsing agent is 5-fluorinated propanol.