CN1159478A - Lowly corrosive cleaner composition - Google Patents

Abstract

A low-corrosion cleaning agent composition, which at least includes an organic solvent-based cleaning agent, a nitrogen-containing organic antirust agent and an epoxy compound as an additive. In the low-corrosivity cleaning agent composition, the organic solvent-based cleaning agent is a kind of hydrocarbon mainly containing 5-20 carbon atoms and organic compounds having 5-20 carbon atoms and one or more polar groups combination. The cleaning composition exhibits excellent flux removal properties and does not corrode the object to be cleaned, so that the composition of the present invention can be ideally used for cleaning electrical components, electronic components, mechanical parts and the like.

Description

Low Corrosive Cleaning Composition

The present invention relates to cleaning compositions for electrical assemblies, electronic assemblies, mechanical parts and the like, and are particularly suitable for removing flux and flux residues from soldered assemblies or parts.

In general, soldering is required to form an electrical circuit on an electrical or electronic device, mechanical part or the like, and it is common practice in the art to apply flux to the device or part prior to soldering to completely and Solder quickly. After the flux is finished, however, the formed flux or flux residue must be removed with a cleaning agent, since it tends to impair the characteristics of the circuit or cause it to corrode.

Chlorinated solvents and freon-type solvents having no flash point and little chemical change have been used as the above-mentioned cleaning agents. However, these solvents are substances that deplete the ozone layer, and thus their use is limited. In these cases, a number of aqueous and solvent-based cleaners have been suggested as alternatives to chlorinated or Freon-type solvents. In addition, cleaning agents containing terpenes (such as limonene, pinene and dipentene) have been described in US Patent Specification 4511488, Japanese Patent Application Publication Table 63-501908 (US Patent Specifications 4640719 and 4740247) etc. in recent years. A class of cleaning agents that pollute the environment and exhibit excellent flux removal properties.

However, these cleaning agents and cleaning agents cannot satisfy all the requirements required for cleaning compositions, including low environmental pollution, low damage, low corrosion, low flammability, low toxicity and high flux-removing performance. That is, cleaning agents containing chlorinated solvents or Freon type solvents have problems in terms of safety, toxicity, environmental pollution and the like. In addition, aqueous cleaners cause rust and lower dryability, and thus are problematic in waste water treatment, etc., although they are less destructive and less toxic than organic solvent-based cleaners. In addition, solvent-based cleaning agents mainly containing non-hydrocarbon solvents are problematic in toxicity and exhibit poor durability due to their easy damage during use, although they are excellent in removing flux. Furthermore, terpenes such as limonene exhibit a low flash point and exhibit poor durability due to their being easily damaged during use, although they are excellent in removing flux. Furthermore, they are compounds derived from natural substances, so it is very difficult to obtain these compounds in constant quality, and they are expensive and limited in supply.

Hydrocarbon cleaners alone are problematic for flux removal, although they rarely cause environmental pollution. Therefore, a class of hydrocarbon-based solvents improved in flux removal performance and in cleaning effect with respect to components or parts by adding polar compounds such as alcohols, ethers or ketones has been described in Japanese Patent Application Laid-Open No. .3-146597 and Japanese Patent Application Publication Form 7-503032. Furthermore, Japanese Patent Application Laid-Open No. 3-146597 also discloses that benzotriazoles can be added to such solvents to protect metals from corrosion.

Among the cleaning agents mentioned above, it is generally feasible in practice to recover and reuse the cleaning agent by distillation in order to reduce the cost of the cleaning agent and the impact on the environment. However, the above polar compounds often decompose in the recovery distillation and/or the cleaning of individual components or parts leads to destruction of the cleaning agent itself or to the formation of explosive peroxides. Japanese Patent Application Laid-Open No. 7-268391 discloses examples in which an antioxidant is also added to suppress the decomposition of polar compounds.

It has been found that when the above cleaning agent comprising a mixture of a hydrocarbon solvent and a polar compound is repeatedly used by distillation recovery, the surface of the component or part cleaned with the fluid used by repeated recovery is also prone to corrosion, even after cleaning When benzotriazole is added to the agent as a rust inhibitor. The cause of this corrosion is considered to be the carboxylic acid formed by the thermal decomposition of the alicyclic carboxylic acid contained in the flux, the oxygen-containing organic compound contained in the flux, or the polar compound contained in the cleaning agent, and the Inorganic halides or hydrogen halides contained in the flux deposits in the fluid make it impossible for benzotriazole alone to prevent rusting. To overcome these problems, some attempts have been made by adding certain epoxy compounds which react with rust inhibitors [Kinzokuhyomen Kogyo Zensho 13 "Kinzoku Fushoku Boshoku Gijutsu, P.56, revised edition (1981)"] or with hydrogen halides , thereby inhibiting the accumulation of acid. More specifically, 2-ethylhexyl glycidyl ether was added in an amount of 0.1% by mass. However, it has been found that when the cleaning agent thus obtained is used repeatedly, the cleaned metal surface corrodes due to repeated recycling (referring to the aforementioned cleaning agent).

SUMMARY OF THE INVENTION The object of the present invention is to overcome the above-mentioned disadvantages of the prior art by providing a cleaning agent composition which has excellent cleaning performance against flux and which can maintain its anti-corrosion effect for a long time.

The inventors of the present invention have once carried out in-depth research to solve the above problems, and found that when epoxy compounds and nitrogen-containing organic antirust agents such as benzotriazole are added to organic solvent-based cleaning agents simultaneously, the resulting cleaning agents can even The preservative effect does not decrease much after repeated recovery by distillation. The present invention has been accomplished based on this finding.

That is, the present invention relates to a low-corrosion cleaning agent composition characterized by comprising at least an organic solvent type cleaning agent, a nitrogen-containing organic antirust agent and an epoxy compound as an additive.

The cleaning composition of the present invention shows significantly reduced corrosiveness even after recovery by distillation and is excellent in flux removal by means of the above specified additives, suitable for cleaning electrical and electronic components, mechanical parts and the like.

Although the mechanism of how the combined use of the epoxy compound according to the present invention and a nitrogen-containing organic rust inhibitor achieves the above-mentioned effects has not been clarified so far, it is considered that the epoxy compound is used simultaneously as a fixing agent for hydrogen halide and the like and as a metal surface inhibitor. Protective agent, the nitrogen-containing organic rust inhibitor is used to protect metal surfaces from corrosion caused by carboxylic acids. At any rate, the cleaning composition of the present invention shows a markedly enhanced antiseptic effect due to the presence of these compounds, and the antiseptic effect does not decrease much even after repeated recovery by distillation.

The organic solvent type cleaning agent used in the present invention is preferably one that causes little environmental pollution, and may be a commercially available cleaning agent, although there is no particular limitation on the cleaning agent. Such cleaning agents include those mainly comprising hydrocarbons having 5-20 carbon atoms, preferably 7-16 carbon atoms, more preferably 9-15 carbon atoms. Hydrocarbons having less than 5 carbon atoms are a fire or explosion hazard during cleaning operations. So there are security issues. On the other hand, hydrocarbons having more than 20 carbon atoms not only show poor flux removal performance, but also cause problems due to the high boiling point of the hydrocarbons, since the recovery operation of the resulting cleaning composition by distillation requires a relatively high consumption. energy and also recover a substantial amount of the flux component when the cleaning composition is recovered by distillation, resulting in a recovered cleaning composition with properties different from the original composition.

When the flux cannot be removed by the hydrocarbon solvent alone, a _C5 - _C20 organic compound having one or more polar groups other than epoxy compounds is added to the hydrocarbon solvent. Examples of such compounds having polar groups include alcohols, ketones, ethers, esters and the like. The organic compound shall be a compound having 5-20 carbon atoms. When the organic compound has 5 or less carbon atoms, there is a risk factor of fire or explosion in handling, and thus safety becomes a problem. On the other hand, hydrocarbons having more than 20 carbon atoms not only show poor flux removal performance, but also cause problems due to the high boiling point of the hydrocarbons, since the recovery operation of the resulting cleaning composition by distillation requires a relatively high consumption. energy and also recover a substantial amount of the flux component when the cleaning composition is recovered by distillation, resulting in a recovered cleaning composition with properties different from the original composition. In particular, it is preferred that the organic compound has 6 to 17 carbon atoms, more preferably 7 to 15 carbon atoms.

When alcohols are used as the above-mentioned organic compounds having polar groups, the alcohols are selected from those compounds each having one or more hydroxyl groups. The use of alcohols having three or more hydroxyl groups is undesirable because the resulting cleaning composition exhibits poor flux removal performance and the low solubility of such solvents in hydrocarbons. Specific examples of alcohols include natural and synthetic alcohols such as 2-ethyl-1-hexanol, hexanol, 1-octanol, 2-octanol, lauryl alcohol, oleyl alcohol, _C20 Guerbet alcohol , 2-cyclo-2-propanol, 1,2-dodecanediol and 1,2-octadecanediol.

The above-mentioned ethers may have 5-20 carbon atoms in the molecule and correspond to the above-mentioned alcohols (wherein the hydrogen atoms of the hydroxyl groups are replaced by C ₁ -C ₄ hydrocarbon groups such as methyl, ethyl, n-propyl, isopropyl , n-butyl, isobutyl, or tert-butyl substituted) ethers which can be prepared by reacting the aforementioned alcohols with the corresponding halogenated hydrocarbons. In addition, the ether may be a cyclic ether of a five-membered or more-membered ring. When the ether has one or more hydroxyl groups, it is preferred that it is selected from ethers having two or less hydroxyl groups. These ethers exhibit excellent flux removal properties. Among these ethers, ethers having a methyl or ethyl group at one end are preferable from the viewpoint of flux removal performance. Specific examples of ethers include dibutyl ether, propylene glycol monobutyl ether, 1,2-diethoxyethane, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, dipropylene glycol methyl ether, benzyl ether, dihexyl ether, etc.

The above-mentioned ketones can be esters having both C ₁ -C ₄ hydrocarbon groups (such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl) and C ₁ -C ₁₅ hydrocarbon groups class, and wherein the number of carbon atoms in the molecule is 5-20. Such ketones can be prepared by oxidation or catalytic dehydrogenation of the corresponding secondary alcohols. The ketones as well as ethers exhibit excellent flux removal properties. Among these ketones, ketones having a methyl or ethyl group at one end are preferable from the viewpoint of flux removal performance.

Similarly, esters can be C ₁ -C ₄ hydrocarbyl (such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl) and C ₁ -C ₁₅ hydrocarbyl Esters, wherein the number of carbon atoms in the molecule is 5-20. Such esters can be prepared by the direct reaction of acids and alcohols. Esters as well as the aforementioned ethers or ketones exhibit excellent flux removal properties. Among these esters, esters having a methyl or ethyl group at one end are preferable from the viewpoint of flux removal performance. Specific examples of esters include butyl acetate, isopentyl acetate, 3-methoxybutyl acetate, butyl propionate, butyl butyrate, isopentyl isovalerate, methyl benzoate, dimalonate, Ethyl esters, ethylene glycol monoacetate, etc.

These organic compounds having one or more polar groups may be added alone or in admixture of two or more. Their amounts are not limited as long as satisfactory flux removal performance is ensured. The amount used is generally 3-50% (by volume), preferably 5-30% (by volume), more preferably about 10-25% (by volume).

Nitrogen-containing organic rust inhibitors used in the present invention include benzotriazole, tolyltriazole, benzotriazole derivatives with C ₂ -C ₁₀ hydrocarbon groups, benzimidazole, imidazole, and C ₂ -C ₂₀ hydrocarbon groups imidazole derivatives, thiazole, thiazole derivatives having a C ₂ -C ₁₀ hydrocarbon group, and the like, which may be used alone or as a mixture of two or more thereof. In particular, benzotriazole, tolyltriazole, and imidazole derivatives having a C ₂ -C ₂₀ hydrocarbon group are preferably used, and these compounds are widely used and exhibit an excellent antirust effect on copper used as a wire. The concentration of the nitrogen-containing organic rust inhibitor is preferably 0.01-2% by mass, more preferably 0.03-1% by mass. When the concentration is less than 0.01% by mass, desired effects cannot be obtained. Concentrations exceeding 2% (by mass) impair the properties of the components being cleaned (eg insulation properties).

The hydrocarbon groups of the imidazole derivatives and thiazole derivatives serve to enhance the solubility of these derivatives in organic solvent-based cleaning agents, and thus can be appropriately selected depending on the cleaning agent used. The number of carbon atoms in the hydrocarbon group is generally 2-20, preferably 5-18, more preferably 10-17.

The hydrocarbon group of the benzotriazole derivative may be suitably selected from those having 2 to 10 carbon atoms (eg, a benzotriazole derivative having a C ₁ hydrocarbon group corresponding to tolutriazole). Preference is given to using benzotriazole derivatives having C ₂ -C ₈ -hydrocarbyl groups, especially derivatives having C ₂ -C ₅ -hydrocarbyl groups.

Epoxy compounds used as additives in the present invention include propylene oxide, epoxycyclooctane, 1,2-epoxybutylene, 1,2-epoxyhexane, 1,2-epoxyheptane, 1, 2-Epoxyoctane, 1,2-Epoxynonane, Allyl Glycidyl Ether, Propyl Glycidyl Ether, Butyl Glycidyl Ether, Amyl Glycidyl Ether, Hexyl Glycidyl Ether , 2-ethylhexyl glycidyl ether, 1,6-hexanediol diglycidyl ether, phenyl glycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether , and glycidyl ethers with 9-15 carbon atoms, cyclohexene oxide, 1-methylcyclohexene oxide, 4-methylcyclohexene oxide, 1,2-dimethylhexene Oxide, 1-ethylcyclohexene oxide, styrene oxide, methyl styrene oxide, etc. These epoxy compounds may be used alone or as a mixture of two or more of them. The number of carbon atoms of the glycidyl ether may be within a certain range such that the obtained glycidyl ether is soluble in cleaning agents. The number is generally 3-20, preferably 5-15, particularly preferably 7-11. The concentration of the epoxy compound may be 0.01-5% by mass, preferably 0.02-2% by mass, more preferably 0.03-1% by mass. Below 0.01% (by mass) the intended effect will not be obtained. On the other hand, concentrations exceeding 5% by mass may cause strong odor or skin irritation.

When a cleaning composition prepared by adding only a nitrogen-containing organic antirust agent such as benzotriazole to an organic solvent-based cleaning agent is used for removing flux, as described above, when detected by a copper corrosion test, by distillation from The recovered fluid in the resulting cleaning composition caused some corrosiveness, although the addition of rust inhibitors had some effect. When the epoxy compound is added alone as an additive, the effect is equivalent to the above-mentioned case of using a nitrogen-containing organic antirust agent.

On the other hand, the cleaning agent composition of the present invention containing both the nitrogen-containing organic antirust agent and the epoxy compound remarkably enhances the antirust effect. As a result of this enhancement, as will be described in the examples, the cleaning composition does not cause corrosion when tested by the copper corrosion test, even after repeated recovery by distillation without removal of the distillation residue. As described above, the simultaneous use of nitrogen-containing organic rust inhibitors and epoxy compounds is more effective than the use of either of them alone.

Although as described above, the cleaning composition of the present invention mainly comprises an organic solvent type cleaning agent, an epoxy compound and a nitrogen-containing organic antirust agent, it may further contain other desired additives. Such additives include antioxidants, surfactants, and the like. As antioxidants, mention may be made of 2,6-di-tert-butylphenol, butylhydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-4-ethyl Phenol, 2,4-diethyl-6-tert-butylphenol, 2,6-di-tert-butyl-4-hydroxymethylphenol, diphenol-p-phenylenediamine, 4-amino-p-di Phenylamine, p, p'-dioctyldiphenylamine, phenyl diisodecyl phosphite, diphenyl diisooctyl phosphite, diphenyl diisodecyl phosphite, Triphenyl phosphate, trinonylphenyl phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol phosphite, dilauryl-3,3'-thiodipropionate, di Cinnamyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate and the like. Although the surfactant used as required is selected from anionic surfactants, cationic surfactants, amphoteric surfactants, etc., the use of nonionic surfactants is optimal because this surfactant has a significant effect on the cleaning agent to be cleaned. The surface has little effect. Preferred examples of the nonionic surfactant include polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenol ethers, polyoxyalkylene alkyl fatty acid esters, polyoxyalkylene allyl phenyl ethers , polyoxyalkylene-sorbitan fatty acid esters, polyoxyalkylene alkylamines, sorbitan fatty acid esters, polyalkylene oxides and the like.

The cleaning composition of the present invention can be used by various methods, such as immersion method, ultrasonic cleaning method, vibration method, spray method or the like, to obtain desired results.

The operation of cleaning printed circuit boards with the cleaning agent composition of the present invention can be carried out effectively by the following methods: for example, continuously carry out ultrasonic cleaning in an ultrasonic cleaning bath equipped with the cleaning agent composition of the present invention and use the cleaning agent combination of the present invention Rinse the resulting printed circuit board.

The present invention is explained in more detail below with reference to Examples, although the present invention is not limited to them.

Example

(Test method) 1% (by mass) of activated turpentine was added to a cleaning agent to prepare a pseudo used cleaning agent for repeatedly removing flux. Put a predetermined amount of pseudo-used cleaning agent into the distillation recoverer, and then add nitrogen-containing organic antirust agent and epoxy compound, just as described in each embodiment. The resulting mixture was distilled at about 6700 Pa and then reused. Fluids thus recycled were tested according to the following copper corrosion test. For comparison, the same cleaning agent as used above but without activated turpentine was subjected to the same recovery procedure as used above and the recovered fluid was subsequently tested according to the copper corrosion test.

As a simulation of the operation of repeatedly performing distillation and recovery, the distillation recovery operation was repeated without removing the distillation residue generated in the distillation recoverer and additionally adding a predetermined amount of the above-mentioned pseudo-used cleaning agent. In this case, nitrogen-containing organic rust inhibitors and epoxy compounds are only added in the first recycling operation.

In the copper corrosion test, 20 ml of the above detergent composition and a surface-polished copper plate (75 mm x 12.5 mm x 3 mm, polished with silicon carbide (grain size: No. 150)) were put into a 50 ml sample vial and sealed. The vial was allowed to stand in a constant temperature bath at 100° C. for 24 hours, and then the corrosion on the surface of the copper plate was visually inspected.

Example 1:

A mixture of 87.5% (by volume) of n-paraffins with a boiling range of 150-215°C and 12.5% (by volume) of 2-ethylhexanol is used as an organic solvent-based cleaning agent, adding 0.1% by mass of benzotriazole as a nitrogen-containing organic rust inhibitor and 0.1% by mass of 2-ethylhexyl glycidyl ether as an epoxy compound. The composition thus obtained was also checked for corrosivity of the fluid reused by distillation according to the copper corrosion test described above. The results are given in Table 1. No difference was found between the two cases with and without activated turpentine.

Example 2:

The above test was carried out in a similar manner to Example 1, except that benzotriazole was replaced by tolyltriazole. The results are given in Table 1. No difference was found between the two cases with and without activated turpentine.

Embodiment 3-6:

Carry out above-mentioned test by the method similar to embodiment 1, just 2-ethylhexyl glycidyl ether is respectively butyl glycidyl ether, 2-methyl octyl glycidyl ether, 1,6-hexanediol glycidyl ether or 1,2-epoxyoctane instead. The results are given in Table 1. In all cases, no corrosion phenomena were observed.

Embodiment 7:

The above test was carried out in a similar manner to Example 1, except that benzotriazole was replaced by undecylimidazole. The results are given in Table 1. No difference was found between the two cases with and without activated turpentine.

Comparative examples 1 and 2:

Compositions prepared by adding only benzotriazole to the same cleaning agent as used in Example 1 and compositions prepared without adding additives were checked in the same manner as in Example 1 by distillation back to Corrosiveness of the fluid used. The results are given in Table 1. In the test in which turpentine was added, the fluid reused from the former caused some rusting, while the fluid reused from the latter caused rusting on the entire surface.

Comparative example 3:

The above test was carried out in the same manner as in Example 1, except that only 2-ethylhexyl glycidyl ether was added to the organic solvent-based cleaning agent. The results obtained are given in Table 1. The results are equivalent to those achieved with the use of benzotriazole alone (comparative example 1).

Table 1 Nitrogen-containing organic additives (add 0.1%) Epoxy compound (add 0.1%) Corrosivity to Copper of Fluids Recycled by Distillation no turpentine added Add turpentine Example 1 Benzotriazole 2-Ethylhexyl glycidyl ether ○ ○ Example 2 Tolutriazole 2-Ethylhexyl glycidyl ether ○ ○ Example 3 Benzotriazole Butyl glycidyl ether ○ ○ Example 4 Benzotriazole 2-Methyloctyl glycidyl ether ○ ○ Example 5 Benzotriazole 1,6-Hexanediol Glycidyl Ether ○ ○ Example 6 Benzotriazole 1,2-Epoxyoctane ○ ○ Example 7 Undecyl imidazole 2-Ethylhexyl glycidyl ether ○ ○ Comparative example 1 Benzotriazole - ○ △ Comparative example 2 - - ○ x Comparative example 3 - 2-Ethylhexyl glycidyl ether ○ △ (Evaluation of Corrosion) ○: No corrosion △: Slight corrosion ×: Significant corrosion

Examples 8 to 10

The same test as described in Example 1 was carried out, except that the organic solvent type cleaning agent was replaced by (a) 80% (by volume) of a commercially available naphthene type solvent (boiling range: 209-245° C.) and 20% ( (by volume) dipropylene glycol monobutyl ether, (b) 80% (by volume) of a commercially available isoparaffin type solvent (boiling range: 197-202°C) and 20% (by volume) of diethylene glycol monobutyl ether Diethyl ether or (c) 80% (by volume) of a commercially available aromatic hydrocarbon type solvent (boiling range: 260-290° C.) and 20% (by volume) of tripropylene glycol instead. The result was the same as in Example 1. No difference was found between the two cases with and without activated turpentine.

Example 11:

The same test as described in Example 3 was performed except that benzotriazole and butyl glycidyl ether were used in amounts of 2% by mass and 0.04% by mass, respectively. The results were the same as in Example 3, and no difference was found between the two cases with activated turpentine and without activated turpentine.

Example 12:

The same test as described in Example 3 was carried out, except that 0.2% (by mass) of turpentine was used and 0.05% (by mass) of benzotriazole and 0.02% (by mass) of butyl glycidyl ether were added to In organic solvent-based cleaning agents. The results were the same as in Example 3, and no difference was found between the two cases with activated turpentine and without activated turpentine.

Examples 13-14:

0.1% (by mass) of benzotriazole and 0.1% (by mass) of 2-ethylhexyl glycidyl ether were added to the organic solvent-based cleaning agent of Example 1, and the operations of distillation and reuse were repeated The simulation experiment (embodiment 13). Similarly, another simulation experiment was carried out, except that 0.2% (by mass) of benzotriazole and 0.04% (by mass) of butyl glycidyl ether were added to the organic solvent-based cleaning agent in Example 1 ( Example 14). The test results are given in Table 2. The fluid recovered after repeating the distillation recovery operation 5 times needs to be checked for corrosion. No corrosion phenomena were observed.

Table 2 Nitrogen-containing organic additives epoxy compound Corrosivity of the fluid to copper after repeated 5 distillation recovery no turpentine added Add turpentine Example 13 Benzotriazole (add 0.1%) 2-Ethylhexyl glycidyl ether (add 0.1%) ○ ○ Example 14 Benzotriazole (add 0.2%) Butyl glycidyl ether (add 0.04%) ○ ○ (Corrosivity evaluation) ○: No corrosion

The cleaning composition of the present invention exhibits excellent flux removal performance and does not corrode the object to be cleaned, so that the composition of the present invention can be ideally used for cleaning electrical components, electronic components, mechanical parts and the like.

Claims (2)

CLAIMS 1. A low-corrosion cleaning agent composition characterized by comprising at least an organic solvent type cleaning agent, a nitrogen-containing organic antirust agent and an epoxy compound as an additive. 2. The low-corrosion cleaning agent composition according to claim 1, wherein the organic solvent type cleaning agent mainly contains hydrocarbons having 5 to 20 carbon atoms and has 5 to 20 carbon atoms and one or more polar groups A composition of organic compounds.