Use of halogenated hydrocarbon solvents as cleaning agents

TECHNICAL FIELD

The present invention relates to novel use of halogenated hydrocarbon solvents.

BACKGROUND ART

1,1,2-Trichloro-1,2,2-trifluoroethane (hereinafter referred to simply as R113) is non-flammable, non-explosive and stable with low toxicity and as such, is widely used as a cleaning agent for a flux employed in the assembling process of electronic parts or precision machine parts or for cutting oils, or as a cleaning agent for clothings such as fur coats or suits. Further, R113 is widely used for removing deposited water after the washing treatment with water of liquid crystal display device parts, electronic parts or precision machine parts. On the other hand, a rinsing agent such as trichloroethylene is used to remove a resist-removing agent deposited on a wafer. 1,1,1-Trichloroethane is used as a cleaning agent to remove a buffing agent deposited on precision metal parts or decorative parts after the buffing treatment thereof. Further, 1,1,1-trichloroethane is used for developing a resist in the preparation of a printed circuit board or a semiconductor circuit, and methylene chloride or perchloroethylene is used for removing the resist after etching treatment.

In spite of its various merits, R113 has been found to destroy ozone in the stratosphere, which in turn brings about a skin cancer. On the other hand, methylene chloride, trichloroethylene, perchloroethylene and 1,1,1-trichloroethane are likely to bring about a pollution of underground water, and it is required to minimize the amount of their use.

US-A-3,080,430 describes fluorine-containing compounds, particuarly 3-chloro-1,1,2,2-tetrafluoropropane, and mentiones the usefullness of this material as a solvent for removing oil, grease and dirt from objects and equipments such motor stators, electrical controls, optical and precision instruments etc..

US-A-3,381,042 and US-A-2,462,402 describe the preparation of halogenated propanes, inter alia 1-chloro-2,2,3,3,3-pentafluoropropanes and 1,3-dichloro-1,2,2,3,3-pentafluoropropanes.

EP-A-0 381 216 and EP-A-0 382 095 which are non-prepublished applications by the present applicant relate to azeotropic or azeotropic-like compositions of hydrochlorofluoropropanes.

Further, it has been described, that hydrogen-containing chlorofluorocarbons such as 1-chloro-1,1-difluoroethane can be used as a solvent for degreasing and defluxing substrates (Research Disclosure No. 146, June 1976, page 13, Abstract No. 14623).

It is an object of the present invention to solve the problems mentioned hereinabove and to provide a halogenated hydrocarbon solvent as a substitute for the conventional solvents.

The present invention provides the use of CF₃CF₂CHCl₂ or CClF₂CF₂CHClF as a cleaning agent.

Preferred embodiments of the invention are indicated in the subclaims.

The compounds used in the present invention are members of the group of compounds represented by the formula:         CH_aCl_bF_cCF₂CH_xCl_yF_z   (I) wherein <maths id="math0001" num=""><math display="inline"><mrow><mtext>a + b + c = 3</mtext></mrow></math><img file="EP0347924B1_D0001.tif" /></maths> , <maths id="math0002" num=""><math display="inline"><mrow><mtext>x + y + z = 3</mtext></mrow></math><img file="EP0347924B1_D0002.tif" /></maths> , <maths id="math0003" num=""><math display="inline"><mrow><mtext>a + x ≧ 1</mtext></mrow></math><img file="EP0347924B1_D0003.tif" /></maths> , <maths id="math0004" num=""><math display="inline"><mrow><mtext>b+y ≧ 1</mtext></mrow></math><img file="EP0347924B1_D0004.tif" /></maths> , and 0 ≦ a, b, c, x, y, z ≦ 3.

Specific examples of the compound of the formula I are as follows: CCℓF₂CF₂CHCℓ₂(R224ca) CCℓ₂FCF₂CHCℓF(R224cb) CF₃CF₂CHCℓ₂(R225ca) CCℓF₂CF₂CHCℓF(R225cb) CCℓF₂CF₂CH₂Cℓ(R234cc) CHF₂CF₂CHCℓF(R235ca) CH₃CF₂CCℓ₂F(R243cc) CHF₂CF₂CH₂Cℓ(R244ca) CH₂CℓCF₂CH₂Cℓ(R252ca) CHCℓ₂CF₂CH₃(R252cb) CH₃CF₂CH₂Cℓ(R262ca) CHF₂CF₂CCℓ₂F(R225cc) CHCℓFCF₂CHCℓF(R234ca) CHF₂CF₂CHCℓ₂(R234cb) CH₂FCF₂CCℓ₂F(R234cd) CF₃CF₂CH₂Cℓ(R235cb) CCℓF₂CF₂CH₂F(R235cc) CH₂CℓCF₂CHCℓF(R243ca) CH₂FCF₂CHCℓ₂(R243cb) CH₂FCF₂CHCℓF(R244cb) CCℓF₂CF₂CH₃(R244cc) CH₂FCF₂CH₂Cℓ(R253ca) CH₃CF₂CHCℓF(R253cb) CF₃CF₂CHCℓF(R226ca) CCℓF₂CF₂CHF₂(R226cb) CCℓ₃CF₂CHCℓ₂(R222c) CCℓ₂FCF₂CHCℓ₂(R223ca) CCℓ₃CF₂CHCℓF(R223cb) CCℓ₃CF₂CHF₂(R224cc) CHCℓ₂CF₂CHCℓ₂(R232ca) CCℓ₃CF₂CH₂Cℓ(R232cb) CCℓ₂FCF₂CH₂Cℓ(R233cb) CHCℓ₂CF₂CHCℓF(R233ca) CCℓ₃CF₂CH₂F(R233cc) CCℓ₃CF₂CH₃(R242cb) CHCℓ₂CF₂CH₂Cℓ(R242ca)    The compounds used in the present invention may be used alone or in combination as a mixture. They are useful as various cleaning agents including a cleaning agent for dry cleaning, a degreasing agent, a cleaning agent for removing a buffing agent, a flux cleaning agent and a rinsing agent    When the compounds used in the present invention are employed for the above-mentioned various purposes, it is preferred to incorporate various other compounds depending upon the particular purposes.

For example, an organic solvent such as a hydrocarbon, an alcohol, a ketone, a chlorinated hydrocarbon, an ester or an aromatic compound, or a surfactant, may be incorporated to improve the cleaning effects in the use as a cleaning solvent or to improve the effects in other uses. Such an organic solvent may be incorporated usually in an amount of from 0 to 80% by weight, preferably from 0 to 50% by weight, more preferably from 10 to 40% by weight, in the composition. The surfactant may be used usually in an amount of from 0 to 10% by weight, preferably from 0.1 to 5% by weight, more preferably from 0.2 to 1% by weight.

The hydrocarbon is preferably a linear or cyclic saturated or unsaturated hydrocarbon having from 1 to 15 carbon atoms and is usually selected from the group constiting of n-pentane, isopentane, n-hexane, isohexane, 2-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, n-heptane, isoheptane, 3-methylhexane, 2,4-dimethylpentane, n-octane, 2-methylheptane, 3-methylheptane, 4-methylheptane, 2,2-dimethylhexane, 2,5-dimethylhexane, 3,3-dimethylhexane, 2-methyl-3-ethylpentane, 3-methyl-3-ethylpentane, 2,3,3-trimethylpentane, 2,3,4-trimethylpentane, 2,2,3-trimethylpentane, isooctane, nonane, 2,2,5-trimethylhexane, decane, dodecane, 1-pentene, 2-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, bicyclohexane, cyclohexene, α-pinene, dipentene, decalin, tetralin, amylene and amylnaphthalene. More preferred are n-pentane, n-hexane, cyclohexane and n-heptane.

The alcohol is preferably an aliphatic or cyclic saturated or unsaturated alcohol having from 1 to 17 carbon atoms and is usually selected from the group consisting of methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl aclohol, isobutyl alcohol, tert-butyl aclohol, pentyl alcohol, sec-amyl alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, 1-nonanol, 3,5,5-trimethyl-1-hexanol, 1-decanol, 1-undecanol, 1-dodecanol, allyl alcohol, propargyl alcohol, benzyl alcohol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 4-methylcyclohexanol, α-terpineol, abietinol, 2,6-dimethyl-4-heptanol, trimethyl nonylalcohol, tetradecyl alcohol and heptadecyl alcohol. More preferred are methanol, ethanol and isopropyl alcohol.

The ketone is preferably represented by one of the formulas <chemistry id="chem0001" num="0001"><img file="EP0347924B1_D0005.tif" /></chemistry> wherein each of R, R' and R'' is a saturated or unsaturated hydrocarbon group having from 1 to 9 carbon atoms and is usually selected from the group consisting of acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, methyl-n-butyl ketone, methyl butyl ketone, 2-heptanone, 4-heptanone, diisobutyl ketone, acetonitrile, acetone, mesityl oxide, phorone, methyl-n-amyl ketone, ethyl butyl ketone, methyl hexyl ketone, cyclohexanone, methylcyclohexanone, isophorone, 2,4-pentanedione, diacetone alcohol, acetophenone and fenchone. More preferred are acetone and methyl ethyl ketone.

The chlorinated hydrocarbon is preferably a satuarted or unsaturated chlorinated hydrocarbon having 1 or 2 carbon atoms and is usually selected from the group consisting of methylene chloride, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane, pentachloroethane, 1,1-dichloroethylene, 1,2-dichloroethylene, trichloroethylene and tetrachloroethylene. More preferred are methylene chloride, 1,1,1-trichloroethane, trichloroethylene and tetrachloroethylene.

As the surfactant for a cleaning agent for dry cleaning, various surfactants including non-ionic, cationic, anionic and amphoteric surfactants may be employed. It is preferably selected from the group consisting of a linear alkyl benzene sulfonate, a long chain alcohol sulfate, a polyoxyethylene ether sulfate, a polyoxyethylene alkyl ether phosphate, a polyoxyethylene alkyl ether sulfate, a polyoxyethylene alkylphenyl ether phosphate, an α-olefin sulfonate, an alkylsulfosuccinate, a polyoxyethylene alkyl ether, a polyoxyethylene alkyl ester, a polyoxyethylene alkylallyl ether, a fatty acid diethanolamide, a polyoxyethylene alkylamide, a sorbitan fatty acid ester, a polyoxyethylene fatty acid ester, a quaternary ammonium salt, a hydroxysulfobetaine, a polyoxyethylenelauryl ether, a polyoxyethylenelauryl ether sodium sulfate, sodium dodecylbenzene sulfonate and a higher alcohol sodium sulfate. More preferred are a polyoxyethylenelauryl ether, a polyoxyethylenelauryl ether sodium sulfate, sodium dodecylbenzene sulfonate and a higher alcohol sodium sulfate.

The aromatic compound is preferably a benzene derivative or a naphthalene derivative and is usually selected from the group consisting of benzene, toluene, xylene, ethylbenzene, isopropylbenzene, diethylbenzene, sec-butylbenzene, triethylbenzene, diisopropylbenzene, styrene, an alkylbenzene sulfonic acid, phenol, mesitylene, naphthalene, tetralin, butylbenzene, p-cymene, cyclohexylbenzene, pentylbenzene, dipentylbenzene, dodecylbenzene, biphenyl, o-cresol, m-cresol and xylenol. More preferred are an alkylbenzene sulfonic acid and phenol.

The ester is preferably represented by one of the following formulas: <chemistry id="chem0002" num="0002"><img file="EP0347924B1_D0006.tif" /></chemistry> wherein each of R₁, R₂, R₃, R₄, R₅ and R₆ is H, OH or a saturated or unsaturated hydrocarbon group having from 1 to 19 carbon atoms. Specifically, it is selected from the group consisting of methyl formate, ethyl formate, propyl formate, butyl formate, isobutyl formate, pentyl formate, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, pentyl acetate, isopentyl acetate, 3-methoxybutyl acetate, sec-hexyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, isopentyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, isopentyl butyrate, isobutyl isobutyrate, ethyl 2-hydroxy-2-methylpropionate, butyl stearate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isopentyl benzoate, benzyl benzoate, ethyl abietate, benzyl abietate, bis-2-ethylhexyl adipate, γ-butyrolactone, diethyl oxalate, dibutyl oxalate, dipentyl oxalate, diethyl malonate, dimethyl maleate, diethyl maleate, dibutyl maleate, dibutyl tertarate, tributyl citrate, dibutyl sebacate, bis-2-ethylhexyl cebacate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, bis-2-ethylhexyl phthalate and dioctyl phthalate. More preferred are methyl acetate and ethyl acetate.

A chlorofluorinated hydrocarbon other than the compound of the formula I may be incorporated to the compound used in the present invention. When azeotropy or pseudoazeotropy exists with a composition obtained by the combination of the compound used in the present invention with other compound, it is preferred to use them under an azeotropic or pseudoazeotropic condition so that there will be no variation in the composition when used by recycling, or no substantial change from the conventional technique will be required.

The cleaning agent for dry cleaning of the present invention may contain various additives such as an antistatic agent, a softening agent, a stain removing agent, a flame retardant, a water and oil repellant or a stabilizer. As the stabilizer, various types which are commonly used for the cleaning agent for dry cleaning, may be employed, including nitroalkanes, epoxides, amines or phenols.

Various cleaning additives or stabilizers may be incorporated also to the degreasing agent, the cleaning agent for the removal of a buffing agent, or a flux cleaning agent. In the case of the cleaning agent for removing a buffing agent, water may further be incorporated. As the cleaning method, wiping by manual operation, dipping, spraying, shaking, supersonic cleaning, steam cleaning or any other conventional method may be employed.

When it is necessary to stabilize the rinsing agent, it is preferred to employ a nitroalkane such as nitromethane, nitroethane or nitropropane, or a cyclic ether such as propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, epichlorohydrin, styrene oxide, butyl glycidyl ether, phenyl glycidyl ether, glycidol, 1,4-dioxane, 1,3,5-trioxane, 1,3-dioxolan, dimethoxymethane or 1,2-dimethoxyethane, in an amount of from 0.001 to 5.0 % by weight, in combination.

Now, the present invention will be described in further detail with reference to Examples.

EXAMPLES 1-1 to 1-7

Cleaning tests for cleaning power were conducted by using the dry cleaning agents as identified in Table 1. A soiled cloth (5 x 5 cm) of wool having carbon soil fixed by a Yukagaku Kyokai method was put into a Scrub-O-meter cleaning machine and washed at 25°C for 25 minutes, whereupon the cleaning effects were measured by an ELREPHO photoelectric reflection meter. The results are shown in Table 1. <tables id="tabl0001" num="0001"><table frame="all"><title>Table 1</title><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" align="center">Example No.</entry><entry namest="col2" nameend="col2" align="center">Dry cleaning agents</entry><entry namest="col3" nameend="col3" align="center">Cleaning effects</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="center">Example 1-1</entry><entry namest="col2" nameend="col2" align="left">R225ca (100)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 1-2</entry><entry namest="col2" nameend="col2" align="left">R225cb (100)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 1-3</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/n-heptane(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 1-4</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/ethanol(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 1-5</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/perchloroethylene(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 1-6</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/acetone(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 1-7</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/sodium dodecylbenzene sulfonate(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row rowsep="1"><entry namest="col1" nameend="col3" align="justify">The value in the bracket ( ) represents a proportion (% by weight).</entry></row></tbody></tgroup></table></tables>

Evaluation Standards:

<dl id="dl0001"><dt>Ⓞ</dt><dd>Stain satisfactorily removed.</dd><dt>○</dt><dd>Stain substantially satisfactorily removed.</dd><dt>△</dt><dd>Stain slightly remained.</dd><dt>X</dt><dd>Stain substantially remained.</dd></dl>

EXAMPLES 2-1 to 2-7

Cleaning tests of cutting oil were conducted by using the degreasing agents as identified in Table 2.

A test piece (25 mm x 30 mm x 2 mm) of SUS-304 was dipped in spindle oil, and then dipped in the degreasing agent for 5 minutes. Then, the test piece was taken out, and the state of the spindle oil remaining on the surface of the test piece was visually evaluated. The results are shown in Table 2. <tables id="tabl0002" num="0002"><table frame="all"><title>Table 2</title><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" align="center">Example No.</entry><entry namest="col2" nameend="col2" align="center">Degreasing agent</entry><entry namest="col3" nameend="col3" align="center">Degreasing effects</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="center">Example 2-1</entry><entry namest="col2" nameend="col2" align="left">R225ca (100)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 2-2</entry><entry namest="col2" nameend="col2" align="left">R225cb (100)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 2-3</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/n-heptane(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 2-4</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/ethanol(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 2-5</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/acetone(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 2-6</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/trichloroethylene(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 2-7</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/ethyl acetate (25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row rowsep="1"><entry namest="col1" nameend="col3" align="justify">The value in the bracket ( ) represents a proportion (% by weight).</entry></row></tbody></tgroup></table></tables>

Evaluation Standards:

<dl id="dl0002"><dt>Ⓞ</dt><dd>Satisfactorily degreased.</dd><dt>○</dt><dd>Substantially satisfactorily degreased.</dd><dt>△</dt><dd>Oil slightly remained.</dd><dt>X</dt><dd>Oil substantially remained.</dd></dl>

EXAMPLES 3-1 to 3-7

Tests for removing a buffing agent were conducted by using the cleaning agents for removing a buffing agent as identified in Figure 3.

A wrist watch frame was polished with a buffing agent (GS-1®, manufactured by Soken Kogyo K.K.) and then immersed in the cleaning agent for removing a buffing agent, and a supersonic wave was applied thereto for 3 minutes. Then, it was taken out and inspected for the removal of the buffing agent. The results are shown in Table 3. <tables id="tabl0003" num="0003"><table frame="all"><title>Table 3</title><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" align="center">Example No.</entry><entry namest="col2" nameend="col2" align="center">Cleaning agent for removing a buffing agent</entry><entry namest="col3" nameend="col3" align="center">Results</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="center">Example 3-1</entry><entry namest="col2" nameend="col2" align="left">R225ca (100)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 3-2</entry><entry namest="col2" nameend="col2" align="left">R225cb (100)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 3-3</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/n-hexane(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 3-4</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/ethanol(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 3-5</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/acetone(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Example 3-6</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/1,1,1-trichloroethane(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="center">Example 3-7</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/ethyl acetate (25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="center">Comparative Example 3-1</entry><entry namest="col2" nameend="col2" align="left">1,1,1-trichloroethane (100)</entry><entry namest="col3" nameend="col3" align="right">○</entry></row><row rowsep="1"><entry namest="col1" nameend="col3" align="justify">The value in the bracket ( ) represents a proportion (% by weight).</entry></row></tbody></tgroup></table></tables>

Evaluation Standards:

<dl id="dl0003"><dt>Ⓞ</dt><dd>Buffing agent satisfactorily removed.</dd><dt>○</dt><dd>Buffing agent substantially satisfactorily removed.</dd><dt>△</dt><dd>Buffing agent slightly remained.</dd><dt>X</dt><dd>Buffing agent substantially remained.</dd></dl>

EXAMPLES 4-1 to 4-6

Flux cleaning tests were conducted by using the flux cleaning agents as identified in Table 4.

A flux (Tamura F-Al-4®, manufactured by Kabushiki Kaisha Tamura Seisakusho) was coated on the entire surface of a printed circuit board (a copper-clad laminate) and baked in an electric furnace at 200°C for 2 minutes. Then, the board was immersed in the flux cleaning agent for one minute. The degree of the removal of the flux is shown in Table 4. <tables id="tabl0004" num="0004"><table frame="all"><title>Table 4</title><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" align="center">Example No.</entry><entry namest="col2" nameend="col2" align="center">Flux cleaning agents</entry><entry namest="col3" nameend="col3" align="center">Cleaning effects</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Example 4-1</entry><entry namest="col2" nameend="col2" align="left">R225ca (100)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="left">Example 4-2</entry><entry namest="col2" nameend="col2" align="left">R225cb (100)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="left">Example 4-3</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/n-heptane(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="left">Example 4-4</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/methanol(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="left">Example 4-5</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/acetone(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row><entry namest="col1" nameend="col1" align="left">Example 4-6</entry><entry namest="col2" nameend="col2" align="left">R225ca(75)/trichloroethylene(25)</entry><entry namest="col3" nameend="col3" align="right">Ⓞ</entry></row><row rowsep="1"><entry namest="col1" nameend="col3" align="justify">The value in the bracket ( ) represents a proportion (% by weight).</entry></row></tbody></tgroup></table></tables>

Evaluation Standards:

<dl id="dl0004"><dt>Ⓞ</dt><dd>Flux satisfactorily removed.</dd><dt>○</dt><dd>Flux substantially satisfactorily removed.</dd><dt>△</dt><dd>Flux slightly remained.</dd><dt>X</dt><dd>Flux substantially remained.</dd></dl>