Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Liquid composition
Reexamination Certificate
1999-09-17
2001-03-20
Gupta, Yogendra (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Liquid composition
C510S170000, C510S174000, C510S177000, C510S273000
Reexamination Certificate
active
06204237
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a nonflammable glycol-based cleaning solvent which is used such as for removing flux from electronic parts, and for cleaning ink, adhesives and other such oils and fats.
2. Description of the Related Art
Glycol-based cleaning solvents are a new type of cleaning solvent which are known to be alternatives to the conventional cleaning solvents containing chlorine or fluorine. These glycol-based cleaning solvents consist mainly of low-toxic, highly-safe propylene glycol-based solvents, and are known to be eco-friendly and less harmful to the earth's ozone shield compared to chlorine/fluorine-containing cleaning solvents. Not only do the glycol-based cleaning solvents have a high KB (kauri-butanol) value and have a good cleansing ability, they scarcely affect plastics and rubber. Therefore, they are particularly used for removing flux from electronic parts, as well as for cleaning ink, adhesives and other oils and fats.
However, almost all propylene glycol-based solvents, which are the main ingredients of the glycol-based cleaning solvents, are flammable substances and classified as hazardous materials. Thus, not only is the management of these solvents strictly regulated under fire-protection law, the amount permitted for storage/equipment is also limited, making these cleaning solvents hard to handle. Therefore, considering that second- and third-class petroleum products (a classification according to Japanese fire-protection law; second-class petroleum products have a flash point ranging between 20° C.-70° C. (at 1 atm), and third-class petroleum products have a flash point ranging between 70° C-200° C. (at 1 atm)) are not so strictly regulated under law, the glycol-based solvents used for cleaning solvents were selected from these two groups. Nonetheless, the cleaning solvents containing glycol-based substances were still classified as hazardous materials, and thus, there existed inconveniences in safety and handling.
SUMMARY OF THE INVENTION
In order to solve the above and other problems, it is an object of the present invention to provide a nonflammable glycol-based cleaning solvent which will not be classified as a hazardous material.
A glycol-based cleaning solvent according to one aspect of the present invention comprises a first ingredient having a flash point of 28° C. or above and comprising one type of propylene glycol-based solvent or a plurality of types thereof, and a second ingredient comprising isopropyl bromide and/or n-propyl bromide, wherein the glycol-based cleaning solvent is given a nonflammable characteristic by mixing 10-70 parts by weight (pts.wt.) of said second ingredient to 100 pts.wt. of said first ingredient.
Isopropyl bromide (synonym: 2-bromopropane, referred to hereinafter as IPB) and n-propyl bromide (synonym: 1-bromopropane, referred to hereinafter as NPB) are known to be nonflammable, incombustible solvents, both of which being disclosed in Japanese Patent No. 2576933, No. 2576941 and No. 2576942. It is possible to turn the glycol-based cleaning solvent into a nonflammable, incombustible substance by mixing IPB and/or NPB to the glycol-based cleaning solvent.
The amount of IPB and/or NPB (10-70 pts.wt.) to be mixed to 100 pts.wt. of propylene glycol-solvent has been determined according to the following two reasons.
(1) IPB and NPB are halogenated hydrocarbon solvents having a characteristic of negatively affecting plastics and rubber. Thus, if an excessive amount of IPB and/or NPB is added, the glycol-based cleaning solvent will lose its advantageous, intrinsic characteristic, i.e., the characteristic of scarcely affecting plastics and rubber. In order not to cancel this beneficial characteristic, it is necessary to keep the amount of IPB and/or NPB below a predetermined level. The specific quantity (10-70 pts.wt.) has been determined according to the test results described later on.
(2) If the amount of IPB and/or NPB is too small, it would become difficult to realize the nonflammability of the cleaning solvent. That is, propylene glycol-based solvents having a high flash point will have to be used for the above-mentioned first ingredient, and this will reduce the dryability of the cleaning solvent and impair its cleaning ability.
Meanwhile, the first ingredient comprised of propylene glycol-based solvent(s) is to have a flash point of 28° C. or above, in order to obtain a nonflammable cleaning solvent which satisfies the conditions described in (1). This specific temperature (28° C.) has been determined according to the test results described later on.
Since the glycol-based cleaning solvent according to the present invention is given a nonflammable characteristic by adding IPB and/or NPB, both of which being nonflammable substances, to a main ingredient comprised of propylene glycol-based solvent(s), it will not be classified as a hazardous material, nor will it render specific restriction under law, such as fire-protection law. Thus, the amount permitted for storage/equipment will not be strictly limited, making these cleaning solvents safer and easier to handle. Further, since the amount of IPB and/or NPB being added to 100 pts.wt. of propylene glycol-based solvent(s) is in the range of 10-70 pts.wt., the cleaning solvent will hardly affect plastics and rubber.
As many different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments described hereinafter.
REFERENCES:
patent: 4056403 (1977-11-01), Cramer et al.
patent: 5792277 (1998-08-01), Shubkin et al.
patent: 6148634 (2000-11-01), Sherwood
patent: 8-337795 (1996-12-01), None
patent: 2576941 (1997-01-01), None
patent: 2576942 (1997-01-01), None
patent: 2576933 (1997-01-01), None
patent: 9-255995 (1997-09-01), None
patent: 10-46197 (1998-02-01), None
patent: 2872664 (1999-03-01), None
patent: 11-172291 (1999-06-01), None
Kaneko Akiyasu
Suzuki Masayasu
Arter & Hadden LLP
Gupta Yogendra
Hitachi Techo Engineering Co., Ltd.
Petruncio John M
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