Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Liquid composition
Reexamination Certificate
1996-08-13
2002-05-28
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Liquid composition
C510S176000, C510S177000, C510S244000, C510S256000, C510S273000, C510S365000
Reexamination Certificate
active
06395699
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a solvent composition useful for a degreasing agent, a defluxing agent, a water-displacement agent or the like which is an agent for removing grease, oil, flux or water attached to an article such as a printed circuit board, an electronic component such as IC, a precision machine part or a glass substrate.
2. Discussion of Background
1,1,2-trichloro-1,2,2-trifluoroethane (hereinafter referred to simply as R113), a solvent mixture composition of this R113 with a solvent soluble therein, or 1,1,1,-trichloroethane, which is excellent in nonflammability, low toxicity and stability, is widely used for various degreasing agents, defluxing agents, etc. R113 has a characteristic such that it selectively dissolves various soils without damaging a precision machine component or a substrate of e.g. metal, plastic or elastomer. Accordingly, it was most suitable for cleaning various electronic components, precision machine parts, optical parts, etc. made of metals, plastics, elastomers, etc.
R113 and 1,1,1-trichloroethane which have been heretofore used, have various merits. However, since they are chemically very stable, they have long atmospheric lifetime and diffuses to the stratosphere, where they will be decomposed by ultraviolet radiation from the sun to release chlorine radicals. Such chlorine radicals will initiate a chain reaction with ozone and deplete the ozone layer. Accordingly, regulations for limiting their production and consumption have been implemented. Therefore, a research has been actively conducted to develop an alternative solvent which scarcely depletes the ozone layer and which is useful as a substitute for conventional R113 or 1,1,1-trichloroethane.
U.S. Pat. No. 5,116,525 discloses azeotropic compositions comprising dichloropentafluoropropane (hereinafter referred to simply as R225), trans-1,2-dichloroethylene (hereinafter referred to simply as t-DE), and methanol (hereinafter referred to simply as MeOH), ethanol (hereinafter referred to simply as EtOH) or isopropanol.
Among them, disclosed as a composition containing MeOH, is an azeotropic composition which comprises from 47 to 57 wt % of R225 comprising from 50 to 75 wt % of 3,3-dichloro-1,1,1,2,2-pentafluoropropane (hereinafter referred to simply as R225ca) and from 25 to 50 wt % of 1,3-dichloro-1,1,2,2,3-pentafluoropropane (hereinafter referred to simply as R225cb), from 38 to 48 wt % of t-DE and from 3 to 9 wt % of MeOH, and which has a boiling point of 43.7° C. under atmospheric pressure of 760 mmHg.
However, it has been found by the present inventors that the above azeotropic composition gives a damage to the material of the article to be cleaned and also has inflammability.
SUMMARY OF THE INVENTION
It is a first object of the present invention to provide a solvent composition comprising R225, t-DE and MeOH, which satisfies the excellent properties which R113 or 1,1,1-trichloroethane has, which can be used as an alternative solvent which gives little influence to the ozone layer and which presents no influence over the material of an article to be cleaned and has no inflammability.
On the other hand, the above-mentioned patent specification discloses, as a composition containing EtOH, an azeotropic composition which comprises from 47 to 57 wt %, preferably 51.7 wt %, of R225 comprising from 50 to 75 wt % of R225ca and from 25 to 50 wt % of R225cb, from 40 to 50 wt %, preferably from 45.3 wt %, of t-DE, and from 1 to 5 wt %, preferably 3 wt %, of EtOH, and which has a boiling point of 46.5° C. under atmospheric pressure of 760 mmHg.
However, it has been found by the present inventors that the above azeotropic composition is not a true azeotropic composition, and it tends to undergo a compositional change.
Accordingly, a second object of the present invention is to provide an azeotropic-like solvent composition having a true composition comprising R225, t-DE and EtOH, which satisfies the excellent properties which R113 or 1,1,1,-triclhoroethane has, which is useful as an alternative solvent which gives little influence to the ozone layer and which undergoes no substantial compositional change.
The present invention provides a solvent composition (hereinafter referred to simply as composition X) comprising (a) R225, (b) t-DE and (c) MeOH, wherein the proportions of (a), (b) and (c) in the total amount of (a), (b) and (c) are from 57 to 75 wt %, from 20 to 35 wt % and from 5 to 8 wt %, respectively.
Further, the present invention provides an azeotropic-like solvent composition (hereinafter referred to simply as composition Y) comprising (a) R225, (b) t-DE and (d) EtOH, wherein the proportions of (a), (b) and (d) in the total amount of (a), (b) and (d) are from 30 to 43 wt %, from 53 to 65 wt % and from 2 to 5 wt %, respectively.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the present invention, R225 represents one or more of dichloropentafluoropropanes represented by the molecular formula C
3
HCl
2
F
5
. R225 is preferably at least one member selected from the group consisting of R225ca and R225cb. Particularly preferred R225 is a mixture of R225ca and R225cb. The blend ratio is preferably R225ca/R225cb=1 to 99 wt %/1 to 99 wt %, more preferably R225ca/R225cb=40 to 75 wt %/25 to 60 wt %.
Composition X of the present invention comprises (a) R225, (b) t-DE and (c) MeOH, wherein the proportions of (a), (b) and (c) in the total amount of (a), (b) and (c) are from 57 to 75 wt %, from 20 to 35 wt % and from 5 to 8 wt %, respectively. Preferred proportions of (a), (b) and (c) in the total amount of (a), (b) and (c) are from 61 to 67 wt %, from 27 to 32 wt % and from 6 to 7 wt %, respectively.
Whereas, composition Y of the present invention comprises (a) R225, (b) t-DE and (d) EtOH, wherein the proportions of (a), (b) and (d) in the total amount of (a), (b) and (d) are from 30 to 43 wt %, from 53 to 65 wt % and from 2 to 5 wt %, respectively. In composition Y of the present invention, preferred proportions of (a), (b) and (d) in the total amount of (a), (b) and (d) are from 40 to 43 wt %, from 53 to 57 wt % and from 2 to 4 wt %, respectively. More preferred proportions are 41.6 wt %, 55.1 wt % and 3.3 wt %, respectively. The composition wherein (a):(b):(d) =41.6:55.1:3.3 wt %, has a boiling point of 44.6° C. under atmospheric pressure of 757 mmHg.
In the present invention, the azeotropic-like composition is meant for a composition whereby the difference in composition between the gas phase and the liquid phase is within 1% with R225, within 1% with t-DE and within 0.5% with EtOH, and the boiling point is within a range of 44.6±0.1° C. under atmospheric pressure of 757 mmHg.
Composition X of the present invention may contain the following compounds in addition to the above-mentioned (a), (b) and (c) in a range not to interfere with the first purpose of the present invention. Likewise, composition Y of the present invention may contain the following compounds in addition to the above-mentioned (a), (b) and (d) within a range not to interfere with the second object of the present invention.
Mainly for the purpose of controlling the solubility, one or more of the following compounds may be added to the compositions of the present invention within a range of from 0.1 to 50 wt %, preferably from 0.1 to 30 wt %, more preferably from 0.1 to 20 wt %.
Hydrocarbons such as n-pentane, 2-methybutane, 2,2-dimethylpropane, n-hexane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, n-heptane, 2-methylhexane, 3-methylhexane, 2,3-dimethylpentane, 2,4-dimethylpentane, n-octane, 2,2,3-trimethylpentane, 2,2,4-trimethylpentane, cyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane.
Chlorinated hydrocarbons such as dichloromethane, cis-1,2-dichloroethylene, trichloroethylene, and tetrachloroethylene.
Ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, and methyl isobutyl ketone.
Ethers such as diethyl ether, methylcellusolve, tetrahydrofuran, and 1,4-dioxane.
Hydrochlorofluorocarbon
Ikehata Michino
Kitamura Kenroh
Tsuzaki Masaaki
Asahi Glass Company Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ogden Necholus
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