Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Specific organic component
Reexamination Certificate
2001-06-25
2004-08-17
Mruk, Brian P. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Specific organic component
C510S247000, C510S267000, C510S361000, C510S375000, C510S434000, C510S476000, C510S488000, C510S492000, C510S533000, C252S175000, C526S085000, C526S086000, C526S222000, C526S227000, C526S229000, C526S318100
Reexamination Certificate
active
06777385
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Technical Field
The present invention relates to: a novel process for obtaining a low-molecular (meth)acrylic acid (salt)-based polymer under high-concentration conditions; the polymer obtained by this process; and uses of this polymer, namely, such as detergent compositions comprising this polymer.
B. Background Art
It has been known well so far that low-molecular acrylic acid-based polymers and so on are very useful for uses such as detergent builders, scale inhibitors, and chelating agents.
And as to production processes for obtaining these low-molecular acrylic acid-based polymers under high-concentration conditions, many production processes are disclosed in such as (I) JP-A-270605/1987, (II) JP-A-086125/1993, (III) JP-A-268304/1992, (IV) JP-A-287208/1994, and (V) JP-A-266904/1992.
In the process disclosed in the above publication (I), (meth)acrylic acid is copolymerized with a copolymerizable ethylenic monomer of a ratio of not more than 10 weight % in a solvent of an alcohol content of not less than 40 weight % in the presence of an inorganic phosphoric acid (salt) of a ratio of 0.01 to 5 weight %.
In the process disclosed in the above publication (II), an aqueous solution of acrylic acid or salt having a pH kept in the range of 6 to 9 is polymerized while nitrogen is introduced into the aqueous solution, thereby obtaining a water-soluble polymer comprising the acrylic acid or salt in a ratio of not less than 95 mol %. The resultant polymer has an average molecular weight of 300 to 10,000 and a dispersion degree of 1.3 to 2.3.
In the process disclosed in the above publication (III), monomers of which the major portion is (meth)acrylic acid are polymerized while being added to a heated aqueous alkali solution together with a peroxide-based polymerization initiator. Set forth in the working-example portion of the publication is an embodiment in which the polymerization is carried out by the steps of initially charging an aqueous sodium hydroxide solution and then heating this solution to 90° C. and then adding drops of the rest of raw materials. If this process is employed, a low-molecular polymer having a number-average molecular weight of 200 to 2,600 can be obtained.
Disclosed in the above publication (IV) is a process for producing a poly(acrylic acid)-based polymer, which process involves aqueous solution polymerization of acrylic acid using hypophosphorous acid or salt as a chain transfer agent. If this process is employed, a polymer having a weight-average molecular weight of not more than 20,000 and a narrow dispersion degree can be obtained.
In the process disclosed in the above publication (V), monomers of which the major portion is (meth)acrylic acid are polymerized in an aqueous solution while the monomers are neutralized with an alkali and while water which is a polymerization medium is distilled off out of the reaction system by evaporation utilizing a heat as generated in the reaction system, thus obtaining the low-molecular (meth)acrylic acid salt-based polymer.
However, even the employment of the above processes has not yet enabled to efficiently produce the low-molecular (meth)acrylic acid (salt)-based polymers under high-concentration conditions.
Specifically, in the case of the art disclosed in the above publication (I), it is necessary to distill off the solvent alcohol at the end of the polymerization, and this distillation not only limits production facilities and apparatuses but also causes a rise of production costs. There are also problems of the below-mentioned eutrophication in that the inorganic phosphoric acid (salt) is used as a polymerization catalyst.
In the case of the art disclosed in the above publication (II), the polymerization is carried out while nitrogen is blown into the solution, but this nitrogen blowing involves scattering of such as monomers, initiators, and chain transfer agents into the air, and therefore causes various problems in aspects of production procedures.
In the case of the art disclosed in the above publication (III), the polymerization is carried out under strong alkaline conditions. In such polymerization in a neutralized state, if the solid content of the reaction system is increased, the viscosity of the aqueous solution of the reaction system greatly rises with the progress of the polymerization, therefore the molecular weight of the resultant polymer tends to greatly increase. In addition, in the working-example portion of the publication, the corrosion is described as not occurring, therefore the details of measures to prevent the corrosion are unclear therefrom, but there are problems in that the measures to prevent the corrosion must always be taken.
In the case of the art disclosed in the above publication (IV), the hypophosphorous acid or salt is used as a chain transfer agent. However, in recent years, the tendency in uses for detergent builders is toward rendering them phosphorus-free in order to prevent eutrophication of rivers and lakes. Therefore, there are problems of being contrary to this tendency.
In the case of the art disclosed in the above publication (V), the polymerization is carried out while water which is a polymerization medium is distilled off by evaporation, and the solid content of the reaction system varies with the amount of water as distilled off, therefore it is difficult to control the polymerization degree or its distribution. In addition, the steps increases by the step of treating the distilled-off water, and further there are limitations in aspects of production facilities and apparatuses because such as recovery facilities are needed.
Besides, there is also a process which involves the use of a sulfite salt as a chain transfer agent. In this process, however, impurities such as mirabilite forms to deteriorate the purity of the resultant polymer. In addition, this process needs facilities for disposing of sulfur dioxide gas generated in the polymerization step, and is therefore limited in aspects of production facilities and apparatuses.
SUMMARY OF THE INVENTION
A. Object of the Invention
The present invention has been made in consideration of the above problems, and its object is to provide a process for efficiently producing a low-molecular (meth)acrylic acid (salt)-based polymer of a good color tone without causing the problems in aspects of production facilities and apparatuses, such as corrosion of apparatuses, and without needing to remove a large amount of alcohols or water, and also without needing to blow nitrogen in, and further, while taking environmental aspects into consideration. Another object of the present invention is to provide favorable uses of the polymer obtained by this process.
B. Disclosure of the Invention
The present inventors diligently studied to solve the above prior art problems. As a result, they have completed the present invention by finding out that the low-molecular (meth)acrylic acid (salt)-based polymer having a good color tone can efficiently be produced under high-concentration conditions, for example, by polymerizing at least one monomer including (meth)acrylic acid in a ratio of not less than 95 mol % under conditions where the neutralization degree is not more than 99 mol % and where hydrogen peroxide and a persulfate salt are used together as initiators, and further by ingeniously controlling the conditions for adding the hydrogen peroxide when this polymerization is carried out.
That is to say, a first production process for a low-molecular (meth)acrylic acid (salt)-based polymer, according to the present invention, comprises the step of polymerizing an aqueous solution of at least one monomer component of a high concentration in the presence of an alkaline substance under conditions where polymerization catalysts are used, wherein: 100 to 95 mol % of the at least one monomer component is a monoethylenically unsaturated monocarboxylic acid (salt) monomer (a) having 3 to 6 carbon atoms; and 0 to 5 mol % of the at least one monomer component is a monoethylenically unsaturated monomer (b) copolymeriza
Fujii Yoshikazu
Hemmi Akiko
Maeda Yoshihiro
Yamaguchi Shigeru
Mruk Brian P.
Nippon Shokubai Co. , Ltd.
Roylance Abrams Berdo & Goodman L.L.P.
LandOfFree
Low-Molecular (meth)acrylicacid(salt)-based polymer and its... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low-Molecular (meth)acrylicacid(salt)-based polymer and its..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low-Molecular (meth)acrylicacid(salt)-based polymer and its... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3360127