JPH0244343B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a cleaning composition for cleaning objects contaminated with resist ink. Resist inks are used in various industrial fields, such as the manufacturing process of printed wiring boards, which is an important field in the electronic equipment industry, for the purpose of protecting boards during etching, plating, soldering, etc. Resist ink is used in the wiring board manufacturing process.
The ink is first screen printed onto a substrate and then cured by means such as heating or UV irradiation to achieve the intended purpose; however, if the uncured ink adhering to the screen is left uncured, it will harden over time and cause the screen to deteriorate. It cannot be reused. Therefore, the screen must be cleaned to remove ink every time printing is interrupted. It is also necessary to remove ink from defective wiring boards due to printing errors and to recycle them. Conventionally, as a cleaning agent for this purpose, a mixture of a thinner such as ethyl acetate or a high boiling point solvent such as butyl cellosolve or butyl carbitol with toluene or trichloroethylene has been used. However, these cleaning agents are flammable,
Problems include slow drying, changes in detergency due to changes in composition during use, difficulty in recycling, and high toxicity. Furthermore, as the performance of ink improves, the solubility of the ink itself decreases, and there are cases in which it cannot be treated with conventional solvents. As a result of various studies, the present inventors have completed a detergent composition for resist ink that, unlike conventional solvents, contains 1,1,1-trichloroethane as a main component. The composition according to the present invention solves the above problems and has a unique function of removing resist ink by dissolving or peeling it off. The resist ink cleaning composition according to the present invention includes:
one or more alcohols selected from i-propanol and 2-methoxyethanol, or the alcohol and ethanol, n-propanol, i-
1 selected from butanol and n-butanol
3.0% alcohol in terms of total alcohol
It consists of 1,1,1-trichloroethane containing from 10.0% by weight. The alcohol content above is 3.0% by weight (hereinafter %)
), the resist ink may dissolve,
Washing and removal by peeling becomes difficult or virtually impossible, and if the concentration exceeds 10.0%, not only will the unique properties of 1,1,1-trichloroethane not be fully utilized, but the evaporation time will become longer and evaporation residue (ring stains) will occur. ), further increasing the risk of flammability. Resist ink adhering to objects such as screens or printed wiring boards is mainly removed by shower cleaning, but depending on the case, immersion cleaning, manual wiping cleaning, etc. are also performed. In either case, solvent remains on the object immediately after cleaning, and if the drying time is slow, not only will the cleaning process become longer and more complicated, but it will also cause smudges in the areas where the solvent droplets are in the final stage of drying. cause obstacles such as Although 2-methoxyethanol may be contained up to 10% without concern for such trouble, it is preferable that the content be 7.5% or less for i-lopanol and 3.5% or less for n-propanol. Further, it is preferable that i-butanol is 1.5% or less and n-butanol is 1.0% or less.
-Butanol and n-butanol are effective to use in combination with other alcohols. On the other hand, in shower cleaning, a large amount of the solvent that is showered is vaporized and dissipated into the air, and the remainder is collected together with the removed resist ink as waste liquid. This collected solvent is also used for rough cleaning, but when contamination with ink becomes significant, it becomes necessary to recover it by distillation and reuse it. Since each of the above-mentioned alcohols has a different boiling point and evaporation characteristics from 1,1,1-trichloroethane, the composition of the distilled and recovered composition will be different from that at the time of preparation. In order to prevent this, in the composition of the present invention, the following i-propanol in group A and at least one alcohol selected from group B are used together, or 2-methoxyethanol in group B and group A are used together. It is desirable to use together with at least one kind of alcohol selected from the following. As a result, the composition of the present invention can be used without decreasing its cleaning power even if it is used continuously. Group A: ethanol, i-propanol Group B: n-propanol, i-butanol, n-
Butanol, 2-methoxyethanol Since the cleaning composition according to the present invention often comes into contact with metals such as aluminum and copper during its use, stabilizers such as 1,1,1-trichloroethane, such as 1, It is desirable to add 4-dioxane, nitromethane, nitroethane or/and butylene oxide, etc.
This makes it possible to further suppress corrosiveness to metals. The composition of the present invention can be used in resist inks used in various fields, preferably etching resist inks and solder resist inks used in the production of printed wiring boards, as well as in the final printing of characters, designs, etc. on wiring boards. The marking ink used for this purpose can also be easily and efficiently washed away. Next, the present invention will be explained in more detail based on test examples. Test (cleaning test) Commercially available solder resist ink A (thermal curing, 2
Liquid type) or B (ultraviolet curing type) are uniformly applied to a polished copper thin plate (20 x 65 m/m) using a bar coder to make a test piece. Put 35ml of cleaning agent and the test piece into a 50ml glass bottle and seal it tightly.
After shaking for 30 seconds using a shaker, check whether there is ink on the test piece. The compositions and test results of the tested cleaning agents are shown in Table-1. From this result, the composition according to the present invention has a cleaning effect superior to that of conventionally used cleaning agents.
It is clear that the general 1,1,1-trichloroethane composition has no cleaning effect at all. Although methanol showed a considerable cleaning effect in this test, it is flammable (tag sealed type) when its content in 1,1,1-trichloroethane exceeds 1.5%, so it was not used for the purpose of the present invention. Doesn't match. In Table 1 below, in experiment numbers 7 to 10, 2
Equal weight mixtures of different alcohols were used, and in runs nos. 17-19 the indicated solvents themselves were used. The meanings of the symbols in the table are as follows. ○: Almost completely removed △: About half removed ×: No removal effect

[Table] Test (dry test) After buffing, prepare a copper plate that has been sufficiently degreased by steam cleaning with trichlorethylene, and apply various cleaning agents on the plate with a microsyringe in a clean bench.
Drop 50μ. Hold the plate horizontally until evaporation is complete and check the evaporation time and the presence of any residue after evaporation. The compositions and test results of the tested cleaning agents are shown in Table 2. The evaporation time is significantly longer than with 1,1,1-trichloroethane, and in order to prevent the formation of a residue (ring stain), i-propanol must be 7.5% or less, n-
It is preferable that propanol be 3.5% or less, i-butanol 1.5% or less, and n-butanol 1.0% or less. On the other hand, if 2-methoxyethanol is 10% or less, problems with evaporation time and residue will not occur.

[Table] Test (dry test) Weigh 100 g of 1,1,1-trichloroethane containing 5% by weight of additives into a 100 ml beaker and leave it indoors. The concentration of the additive accompanying the evaporation of 1,1,1-trichloroethane was measured, and the amount of evaporation was 25
% and the residual ratio of the additive when it reached 50%. The types of additives and test results are shown in Table-3. When the residual ratio of the additive greatly exceeds 1, the concentration of the additive in the evaporated and recovered 1,1,1-trichloroethane becomes low, while when the residual ratio greatly falls below 1, the concentration of the additive in the recovered 1,1,1-trichloroethane decreases. Both are disadvantageous in terms of recovery and reuse because the additive concentration increases. Therefore, by using the following i-propanol in group A and an alcohol selected from group B, or 2-methoxyethanol in group B and an alcohol selected from group A as additives, the composition of the present invention can be prepared. It becomes possible to maintain the cleaning effect. Group A: ethanol, i-propanol Group B: n-propanol, i-butanol, n-
Butanol, 2-methoxyethanol

[Table] Example of ratio of additive concentration after evaporation Using a commercially available small shower cleaner for screen plates and a cleaning composition consisting of 1,1,1-trichloroethane containing the following additives. A screen (35 x 55 cm, made of polyester, aluminum frame screen) to which etching resist ink, solder resist ink (Test A) or marking ink had been adhered was washed. i-propanol 4.0% i-butanol 1.5〃 1,4-dioxane 2.5〃 nitromethane 0.5〃 ethanol 2.0% n-propanol 2.0〃 2-methoxyethanol 1.0〃 1,4-dioxane 1.0〃 butylene oxide 0.3〃 nitromethane 0.5〃 Above 2 15 screens for each type of cleaning composition (5 for each ink)
When the screen was shower washed at a shower rate of 30/min and a washing time of 3 to 5 minutes, each resist ink adhering to the screen was completely removed in all cases. No changes were observed in the screen, masking area, or aluminum frame after cleaning.

Claims (1)

[Claims] 1 one or more alcohols selected from i-propanol and 2-methoxyethanol, or the alcohol and ethanol, n-propanol,
A resist ink cleaning composition comprising 1,1,1-trichloroethane containing 3.0 to 10.0% by weight of one or more alcohols selected from i-butanol and n-butanol.