Process for producing acid-type maleic acid polymer and water-treating agent and detergent additive containing said polymer

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing an acid-type polymaleic acid and acid-type maleic acid copolymer having acrylic acid structural units in the molecule and also to their usage as a water treating agent, detergent builder, and chelating agent. More particularly, the present invention is concerned with a process for producing efficiently and economically acid-type polymaleic acid or acid-type maleic acid copolymer of high quality using water as the solvent and a specific polymerization catalyst, and also with a water treating agent and detergent additive containing the thus produced polymer. According to the process of the present invention, it is possible to produce acid-type polymaleic acid and acid-type maleic acid copolymer of high quality having a narrow molecular-weight distribution and a low molecular weight.
2. Description of the Prior Art
Maleic acid (co)polymers have been in general use as a water treating agent, detergent additive, dispersing agent, and chelating agent. There are many processes for their production as disclosed in, for example, Japanese Patent Laid-open Nos. 168906/1982 (U.S. Pat. Nos. 4519920, 4555557), 64613/1984, 64615/1984 (U.S. Pat. No. 4668735), 176312/1984(U.S. Pat. No. 4589995), 210913/1984 (U.S. Pat. No. 4668735), 213714/1984, 212410/1985, 178097/1986, 218407/1987 (U.S. Pat. No. 4659793), 114986/1988, 235313/1988, and 236600/1988, and Japanese Patent Publication No. 54005/1981.
Unfortunately, these processes yield maleic acid (co)polymers which are unsatisfactory in performance because they have such a high molecular weight and/or a broad molecular-weight distribution that they are liable to gelation through chelation with cations (such as Ca ions) in water. Therefore, there has been a demand for maleic acid (co)polymers having a low molecular weight and a narrow molecular-weight distribution.
In addition, the production processes disclosed so far yield maleic acid (co)polymers in the form of salt such as ammonium salt, sodium salt, and potassium salt. A disadvantage of such products is poor miscibility with nonionic surface active agents in the case where they are used as a detergent additive such as detergent builder. Thus they make it difficult to produce stable liquid detergent compositions and their use is greatly limited. Another disadvantage of salt-type maleic acid (co)polymers is that they cannot be made into a one-pack type water treating agent which is composed of a maleic acid (co)polymer and zinc, because they are less miscible with zinc than acid-type maleic acid polymers.
There are disclosed processes for producing maleic acid (co)polymers having a narrow molecular-weight distribution in Japanese Patent Laid-open Nos. 212411/1985 (U.S. Pat. No. 4709091) and 212412/1985. A disadvantage of these processes is that they involve polymerization which is performed in two stages according to the degrees of neutralization, which leads to a long polymerization time and complex operation. Another disadvantage arises from using a persulfate as the catalyst which would corrode the reaction vessel made of SUS-304 or the like. Moreover, these processes yield only salt-type maleic acid (co)polymers, which are poor in performance as a detergent additive and water treating agent, as mentioned above.
In contrast with salt-type maleic acid (co)polymers, acid type maleic acid (co)polymers are free of the above-mentioned disadvantages and exhibit outstanding characteristic properties when used as a water treating agent and detergent additive. The acid-type maleic acid (co)polymers can be produced by eliminating alkali metal ions from the salt-type maleic acid (co)polymers. This process, however, is not desirable because it needs complex operations and leads to a high production cost. And yet it does not eliminate the serious drawback of yielding polymers having a high molecular weight and a broad molecular-weight distribution.
On the other hand, there are disclosed processes for producing acid-type maleic acid (co)polymers in Japanese Patent Laid-open No. 19089/1976 and Japanese Patent Publication Nos. 57482/1982 (U.S. Pat. No. 3919258) and 36042/1987 (U.S. Pat. No. 4212788). These processes include the steps of polymerizing maleic acid anhydride alone or in combination with other polymerizable monomers in an organic solvent (such as toluene and xylene) in the presence of an oil-soluble polymerization initiator (such as benzoyl peroxide, azobisisobutyronitrile, and di-t-butyl peroxide), distilling out the solvent, and hydrolyzing the resulting polymer to give an acid-type maleic acid (co)polymer. These processes, however, are not advantageous from the standpoint of increased steps, potential dangers, high production cost, and waste of material, which arise from the polymerization performed in an organic solvent.
The above-mentioned processes have another disadvantage that they yield maleic acid (co)polymers which, when used as an antiscale agent, are liable to combine with alkaline earth metal ions (such as Ca ions and Mg ions) in water being treated, forming insoluble salts and resulting in insufficient scale prevention. This is because the maleic acid (co)polymer has extremely hydrophobic groups such as aromatic hydrocarbon residues (originating from the polymerization solvent) and t-butyl groups (originating from the polymerization initiator).
There is disclosed in Japanese Patent Laid-open Nos. 91295/1987 and 91296/1987 (GB 2181735) a process for producing a salt-type maleic acid (co)polymer as an antiscale agent by using a mixture of water and alcohol and/or ketone containing FeSO.sub.4 as the polymerization solvent and hydrogen peroxide as the polymerization catalyst. This process, however, has some shortcomings. That is, it does not perform (co)polymerization quite well. In the case of copolymerization with acrylic acid, it does not introduce acrylic acid units evenly into the main chain of the resulting polymer, and hence the resulting copolymer has a broad molecular-weight distribution and is liable to decarbonization when used at high temperatures. In addition, the process leaves much monomer unpolymerized. If the polymerization solvent contains a high-boiling solvent (such as methyl ethyl ketone), it remains in the resulting polymer, posing a problem of odor and safety. Moreover, the polymer produced by this process is not satisfactory when used as a water treating agent and detergent additive.
There have been proposed several processes for producing maleic acid copolymers and usages of maleic acid copolymers in Japanese Patent Laid-open Nos. 126810/1982, 122906/1983, 147412/1983, and 68806/1987. The processes proposed in the first two patent applications yield maleic acid copolymers having a broad molecular-weight distribution, containing a large amount of residual monomer, and lacking biodegradability. The processes proposed in the last two patent applications yield maleic acid copolymers which are poor in biodegradability.
There is a description in U.S. Pat. No. 4314044 and U.S. Pat. No. 3635915 about the fact that a redox polymerization catalyst composed of a polyvalent metal ion such as Fe.sup.2+ (as a reducing agent) and a peroxide is effective in the copolymerization of an unsaturated dicarboxylic acid (such as maleic acid) and an unsaturated monocarboxylic acid (such as acrylic acid). A disadvantage of this redox polymerization is that the polyvalent metal ion (especially Fe.sup.2+) should be used in an amount of 1/150 to 1/10 mol per mol of the peroxide to bring about the oxidation-reduction reaction between the peroxide (as the initiator) and the polyvalent metal ion (as the reducing agent), and the polyvalent metal ion contaminates or discolors the product. In addition, the redox polymerization yields only a maleic acid copolymer having a broad molecular-weight distribution which is not suitable for use as a water treating agent and detergent additive
There is disclosed in Japanese Patent Laid-open No. 218407/1987 (U.S. Pat. No. 4659793) a process for producing an aqueous solution of a dicarboxylic acid copolymer, said process comprising reacting an ethylenic unsaturated dicarboxylic acid which is at least partially neutralized and an .alpha.,.beta.-ethylenic unsaturated monomer in the presence of a water-soluble polymerization initiator and a polyvalent metal ion, while keeping the aqueous solution system at pH 2-7. This process yields a salt-type maleic acid copolymer such as the one mentioned above. The copolymer has an advantage of containing only a small amount of unreacted monomer but also has a disadvantage of being poor in miscibility with a nonionic surface active agent and Zn. Moreover, the copolymer cannot be made into an acid-type maleic acid copolymer by the removal of alkali metal without increase in manufacturing steps and production cost.
There are other processes for producing the polymer by performing the polymerization by the aid of a polymerization initiator and a polyvalent metal ion, as disclosed in Japanese Patent Laid-open Nos. 62804/1987 (U.S. Pat. No. 4786699) and 267307/1987 (EP 242791). These processes are concerned with the production of polyvinyl pyrrolidone and polyarylamine.
SUMMARY OF THE INVENTION
The present invention was completed to overcome the above-mentioned disadvantages involved in the prior art technology. Accordingly, it is an object of the present invention to provide a process for producing in a simple, economical manner an acid-type polymaleic acid and acid-type maleic acid copolymer useful as a water-treating agent and detergent additive, especially an acid-type polymaleic acid and acid-type maleic acid copolymer having a low molecular weight and a narrow molecular-weight distribution. It is another object of the present invention to provide an inexpensive, high-performance water-treating agent and detergent additive which are based on the acid-type polymaleic acid and acid-type maleic acid copolymer produced by the above-mentioned process. In the description in this specification, the acid-type polymaleic acid and acid-type maleic acid copolymer may be collectively referred to as acid-type maleic acid polymer.
The gist of the present invention resides in a process for producing an acid-type maleic acid polymer having a number-average molecular weight of 300-5000 and a D-value smaller than 2.5 (defined below), said process comprising polymerizing in an aqueous solution a monomer component composed of maleic acid (A) alone or a monomer component composed of 50-99.9 wt % of maleic acid (A) and 50-0.1 wt % of other water-soluble unsaturated monomer (B), in the presence of at least one metal ion selected from the group consisting of iron ion, vanadium atom-containing ion, and copper ion in an amount of 0.5-500 ppm of said monomer component, by the aid of hydrogen peroxide as the polymerization catalyst in an amount of 8-100 g per mol of said monomer.
D value=M.sub.W /M.sub.N
M.sub.W =weight-average molecular weight
M.sub.N =number-average molecular weight
The gist of the present invention also resides in a water-treating agent or detergent additive which contains the acid-type maleic acid polymer obtained by the above-mentioned process.
According to the process of the present invention, an acid type polymaleic acid (homopolymer) is obtained from the monomer component composed of maleic acid (A) alone and an acid-type maleic acid copolymer is obtained from the monomer component composed of maleic acid (A) and other water-soluble unsaturated monomer (B). In either cases, it is necessary that water should be used alone as the polymerization medium. If the polymerization medium is a hydrophilic solvent such as alcohol and ketone or a mixture of water and a hydrophilic solvent, it is impossible to produce the acid-type polymaleic acid (homopolymer) having the acrylic acid structure in the main chain, or it is impossible to produce the acid-type maleic acid copolymer in which maleic acid (A) and water-soluble monomer (B) are evenly copolymerized. In addition, the resulting polymer or copolymer contains a large amount of unreacted monomers.
According to the process of the present invention, water is used alone as the polymerization medium and polymerization is performed under specific conditions, so that the polymerization of acid-type monomer proceeds efficiently and the resulting polymer contains terminal groups different from those of conventional maleic acid (co)polymers. The maleic acid polymer in the present invention is suitable for use as a water-treating agent and detergent additive because it has a low molecular weight and a narrow-molecular weight distribution.
By the way, the process of the present invention differs from the conventional process in that acid-type maleic acid is polymerized, without being changed previously into salt-type maleic acid, under specific polymerization conditions. In many of the conventional processes, salt-type maleic acid is used as the starting material because acid-type maleic acid does not readily polymerize in an aqueous medium, which prevents the efficient production of monomers Moreover, the process of the present invention provides polymers having a narrow molecular-weight distribution and highly reactive terminal groups, which make the polymers suitable for use as a water-treating agent and detergent additive. The process of the present invention is simple because it yields the acid-type maleic acid polymer directly. Also, the process of the present invention yields high-quality polymers which cause contamination very little because it uses only a small amount of metal ions.
According to the process of the present invention, the copolymer is produced from maleic acid (A) and other water-soluble unsaturated monomer (B) as the copolymer component. Examples of the water-soluble unsaturated monomer (B) include the following. Unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, .alpha.-hydroxyacrylic acid, and crotonic acid; unsaturated polycarboxylic acids such as fumaric acid, itaconic acid, citraconic acid, and aconitic acid; vinyl acetate; unsaturated hydroxyl group-containing compounds such as 3-methyl-3-buten-1-ol (isoprenol), 3-methyl-2-buten-1-ol (prenol), and 2-methyl-3-buten-2-ol (isoprene alcohol), and their adducts with 1-100 mol of ethylene oxide and/or propylene oxide, which are represented by the general formula (1) below; ##STR1## (where R.sup.1 and R.sup.2 independently denote hydrogen or a methyl group (but do not denote a methyl group simultaneously); R.sup.3 denotes --CH.sub.2 --, --(CH.sub.2).sub.2 --, or --C(CH.sub.3).sub.2 --; R.sup.1, R.sup.2, and R.sup.3 contain 3 carbon atoms in total; Y denotes an alkylene group having 2-3 carbon atoms; and n is 0 or an integer 1-100); unsaturated (meth)allyl ethers such as 3-allyloxy-2-hydroxypropanesulfonic acid, and glycerol monoallyl ether, and their adducts with 1-100 mol of ethylene oxide and/or propylene oxide, which are represented by the formula (2) below; ##STR2## (where R.sup.1 denotes hydrogen or a methyl group; a, b, d, and f denote independently 0 or an integer of 1-100 and a+b+d+f=0-100; the --OC.sub.2 H-- units and the --OC.sub.3 H-- units may be connected in any order; and Z denotes a hydroxyl group, sulfonic group, or phosphoric (or phosphorous) group if the sum of d and f is 0, or a hydroxyl group if the sum of d and f is a positive integer of 1-100); unsaturated sulfonic group-containing compounds such as vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid, sulfoethyl (meth)acrylate, sulfopropyl (meth)acrylate, 2-hydroxysulfopropyl (meth)acrylate, and sulfoethylmaleimide; monoesters or diesters composed of an adduct of C.sub.1-20 alkyl alcohol with 0-100 mol of ethylene oxide and/or propylene oxide and an unsaturated carboxylic acid such as (meth)acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, aconitic acid; and monoesters or diesters composed cf an unsaturated carboxylic acid such as (meth)acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and aconitic acid, and 1-100 mol of ethylene oxide and/or propylene oxide.
These monomers may be used alone or in combination with one another. Maleic acid is readily produced by reacting maleic anhydride and water, so in present invention, it is obvious that maleic anhydride may be used instead of maleic acid.
In the case where the acid-type maleic acid copolymer of the present invention is intended for use as a water-treating agent or detergent additive, the adequate water-soluble monomer (B) is selected from the unsaturated monocarboxylic acids (particularly acrylic acid and methacrylic acid), the unsaturated alcohols (particularly isoprenol and polyethylene glycol monoisoprenol ether) represented by the general formula (1) above, and unsaturated allyl ethers (particularly glycerol monoallyl ether and 3-allyloxy-2-hydroxypropanesulfonic acid) represented by the general formula (2) above.
According to the process of the present invention, the maleic acid (A) and the water-soluble monomer (B) should be used in a ratio of 50-99.9 wt % (preferably 75-99.9wt %) for the former and 50-0.1 wt % (preferably 25-0.1 wt %) for the latter. If the water-soluble monomer (B) is used in an amount more than 50 wt %, the resulting polymer contains an undesirably large amount of residual monomer which makes the polymer unsuitable for use as a detergent additive and also makes the polymer poor in biodegradability.
The process of the present invention employs metal ions. Examples of the metal ions include iron ion, vanadium atom-containing ion, and copper ion. Preferable among them are Fe.sup.3+, Fe.sup.2+, Cu.sup.+, CU.sup.2+, V.sup.2+, V.sup.3+, VO.sup.2+, and VO.sub.3.sup.-. Particularly desirable metal ions include Fe.sup.3+, CU.sup.2+, and VO.sup.2+. They may be used alone or in combination with one another.
According to the process of the present invention, the metal ion should be used in an amount of 0.5-500 ppm, preferably 5-100 ppm, of the monomer component. With an amount less than the lower limit, the metal ion does not increase the rate of polymerization or copolymerization When the metal ion is used in an amount more than the upper limit, the acid-type maleic acid polymer becomes discolored and have such a broad molecular-weight distribution that it is unsuitable for use as a water-treating agent and detergent additive and is poor in biodegradability.
The metal ion can be used in any form so long as it become ionized in the polymerization system. Examples of the metal compounds that can be used include water-soluble metal salts such as vanadium oxychloride, vanadium trichloride, vanadyl oxalate, vanadyl sulfate, vanadic anhydride, ammonium metavanadate, ammonium hypovanadous sulfate [(NH.sub.4).sub.2 SO.sub.4 .multidot.VSO.sub.4 .multidot.6H.sub.2 O], ammonium vanadous sulfate [(NH.sub.4)V(SO.sub.4).sub.2 .multidot.12H.sub.2 O], copper (II) acetate, copper (II) bromide, copper (II) acetylacetate, cupric ammonium chloride, copper carbonate, copper (II) Chloride, copper (II) citrate, copper (II) formate, copper (II) hydroxide, copper nitrate, copper naphthenate, copper oleate, copper maleate, copper phosphate, copper (II) sulfate, cuprous chloride, copper (I) cyanide, copper iodide, copper (I) oxide, copper thiocyanate, iron acetylacetonate, iron ammonium citrate, ferric ammonium oxalate, ferrous ammonium sulfate, ferric ammonium sulfate, iron citrate, iron fumarate, iron maleate, ferrous lactate, ferric nitrate, iron pentacarbonyl, ferric phosphate, and ferric pyrophosphate; metal oxides such as vanadium pentaoxide, copper (II) oxide, ferrous oxide, and ferric oxide; metal sulfides such as copper sulfide and iron sulfide; and copper powder and iron powder.
The above-mentioned metal ions may be used in combination with a chelating agent to adjust the concentration of the metal ions. Examples of the chelating agent that can be used in the present invention include polyphosphoric acid, pyrophosphoric acid, hexametaphosphoric acid, and tripolyphosphoric acid; aminocarboxylic acids such as ethylenediaminetetraacetic acid, nitrilotriacetic acid, and diethylenetriaminepentaacetic acid; phosphonic acid such as 1-hydroxyethylidene-1,1-diphosphonic acid and 2-phosphonobutane-1,2,4-tricarboxylic acid; organic acids such as fumaric acid, malic acid, citric acid, itaconic acid, oxalic acid, and crotonic acid; and polycarboxylic acids such as polyacrylic acid.
According to the process of the present invention, the polymerization temperature should be 50.degree.-160.degree. C., preferably 70.degree.-160.degree. C., and more preferably 85.degree.-150.degree. C. With a polymerization temperature lower than 50.degree. C., polymerization does not proceed smoothly. With a polymerization temperature higher than 160.degree. C., polymerization is accompanied by thermal decomposition. The solid contents in the polymerization system at the time of polymerization should be in the range of 30-99%, preferably 40-95%, so that the amount of residual maleic acid can be reduced further.
According to the process of the present invention, the polymerization proceeds as hydrogen peroxide (polymerization catalyst) is added. The polymerization evolves carbon dioxide, presumably as the result of decarbonization from the maleic acid and/or acid-type maleic acid polymer present in the polymerization system. The amount of the carbon dioxide evolved during polymerization is proportional to the amount of hydrogen peroxide added. Therefore, it is possible to control the amount of decarbonization by controlling the amount of hydrogen peroxide to be added. This, in turn, makes it possible to control, as required, the amount of carboxyl groups in the acid-type maleic acid polymer. This is a great advantage of the present invention because the acid-type maleic acid polymer can be made suitable for a broad range of applications by controlling the amount of carboxylic acid which greatly affects the physical properties and performance of the acid-type maleic acid polymer.
In the process of the present invention, hydrogen peroxide should be used in an amount of 8-100 g, preferably 10-80 g, and more preferably 15-50 g; per mol of the monomer component. With less than 8 g of hydrogen peroxide, the polymerization system will permit more maleic acid to remain unreacted. With more than 100 g of hydrogen peroxide, no additional effect is produced and excess hydrogen peroxide will remain in the polymerization system.
According to the process of the present invention, hydrogen peroxide should not be replaced by any other polymerization catalysts. It is impossible to obtain the high-quality acid-type polymaleic acid and acid-type maleic acid copolymer having a narrow molecular-weight distribution and a low molecular weight as in this invention, and the resulting polymer would contain an extremely large amount of residual monomer, if hydrogen peroxide is replaced by persulfate such as ammonium persulfate, sodium persulfate and potassium persulfate; azo compounds such as 2,2'-azobis -(2-amidinopropane) hydrochloride, 4,4'-azobis-4-cyanovaleric acid, azobisisobutyronitrile, and 2,2' -azobis-(4-methoxy-2,4-dimethylvaleronitrile; or organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, persuccinic acid, di-t-butyl peroxide, t-butylhydroperoxide, and cumenehydroperoxide.
There are no limitations on the method of feeding hydrogen peroxide to the polymerization system. It may be charged into the system all at once in the initial stage of the reaction, or continuously or by portions during the reaction. For the polymerization to proceed smoothly, continuous feeding is desirable and repetition of continuous feeding at certain intervals is more desirable. It is most desirable that the continuous feeding should be performed for a certain period of time, suspended for a while, and resumed. The feeding of hydrogen peroxide in this manner considerably decreases the amount of monomer which remains unreacted. There are no specific limitations on when, how long, and how often the feeding of hydrogen peroxide should be suspended, and also on the temperature of the system at the time of suspension. These parameters should be properly determined according to how the monomer component is being supplied to the system. The period of suspension should usually be 10-160 minutes, preferably 30-120 minutes; the frequency of suspension should be 1-3 times; and the temperature in the period of suspension should be 50.degree.-160.degree. C., preferably 85.degree.-160.degree. C., more preferably 100.degree.-150.degree. C. The feeding before and after suspension should continue for 10-200 minutes, preferably 20-120 minutes.
In the meantime, the above-cited Japanese Patent Laid-open No. 218407/1987 (U.S. Pat. No. 4659793) mentions that the combined use of iron and hydrogen peroxide as the polymerization catalyst is effective in reducing residual maleic acid in the synthesis of a salt of maleic acid-acrylic acid copolymer (in the ratio of 10-70/90-30 by weight). A disadvantage of this process is that the polymerization system should be kept at pH 2-7 to lower the amount of residual monomer and, on the other hand, the higher the ratio of maleic acid increases, the higher the pH value should be. In addition, this process yields a salt of maleic acid copolymer which is not suitable for use as a water-treating agent and detergent additive and is poor in biodegradability.
The process of the present invention which is carried out as mentioned above yields an acid-type maleic acid polymer which has a number-average molecular weight of 300-5000, preferably 400-3000, and a D-value smaller than 2.5, preferably smaller than 2.0. (The D-value represents the molecular weight distribution defined by M.sub.W /M.sub.N, where M.sub.W =weight-average molecular weight and M.sub.N =number-average molecular weight.)
The acid-type maleic acid polymer obtained as mentioned above may be used as such for a variety of applications. However, it may be neutralized with a proper basic compound according to the object of the use.
The acid-type maleic acid polymer obtained by the process of the present invention exhibits its outstanding properties when used as a detergent additive because it is highly miscible with a nonionic surface active agent in the detergent composition, or when used as a water-treating agent because it is less liable to gelation even when incorporated with zinc for the improvement of corrosion resistance. The acid-type maleic acid polymer obtained by the process of the present invention exhibits its outstanding properties (including good biodegradability) when used as a detergent additive and water-treating agent because it has a low molecular weight and a narrow molecular-weight distribution attributable to the unique polymerization conditions mentioned above. The acid-type maleic acid polymer obtained by the process of the present invention does not have any adverse effects (such as lowering of purity, separation of metal salt, and degradation of color) on the product with which it is used, because the process employs only a small amount of metal ion.
According to the process of the present invention, the acid-type maleic acid polymer is produced by polymerization in an aqueous solution. This process eliminates the possibility that the polymer contains residual organic solvents harmful to the human body, unlike the conventional process by which polymerization is performed in an organic solvent and then the organic solvent is replaced by water. The solventless process is shorter and less dangerous than the conventional process.
The process of the present invention yields the acid-type maleic acid polymer which will find use as a scouring assistant for cellulosic fiber, bleaching assistant for cellulosic fiber, pretreating agent for pulp bleaching, preparing agent for bentonite mud, deodorant (formed in combination with a polyvalent metal such as iron, copper, manganese, and zinc), dispersing agent for inorganic pigments, deinking assistant for waste paper regeneration, and chelating agent.

BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an NMR chart of the acid-type polymaleic acid (1) obtained in the example of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described in more detail with reference to the following examples, which are not intended to restrict the scope of the invention. In Examples, "%" and "parts" mean "wt %" and "parts by weight", respectively.
EXAMPLE 1
A 1-liter four-neck flask equipped with a thermometer, stirrer, and reflux condensed was charged with 196 parts of maleic anhydride, 75.1 parts of water (to make 232 parts of maleic acid), and 0.01 parts of iron (III) ammonium sulfate dodecahydrate (equivalent to 5 ppm of Fe.sup.3+ based on the amount of maleic acid charged). The resulting aqueous solution was heated with stirring to the boiling point under normal pressure. Then, 96.3 parts of 60% hydrogen peroxide (equivalent to 28.9 g for 1 mol of maleic acid charged) was added dropwise with stirring continuously over 3 hours, during which polymerization proceeded. Stirring was continued for another 1 hour at the boiling point of the system. After the completion of polymerization, there was obtained sample (1) of acid-type polymaleic acid containing 63% solids. The sample was tested for molecular weight and molecular-weight distribution by gel permeation chromatography under the following conditions. The results are shown in Table 1. Column: G-3000PW (XL)+G-2500PW (XL) made by Toso Co., Ltd., eluent: phosphate buffer solution (pH 7), and reference sample for molecular weight: polyethylene glycol (made by General Science Co., Ltd.)
EXAMPLES 2 TO 9
The same procedure as in Example 1 was repeated to give samples (2) to (9) of acid-type polymaleic acid, except that the amounts of iron (III) ammonium Sulfate dodecahydrate and hydrogen peroxide were changed as shown in Table 1. The samples were analyzed in the same way as in Example 1. The results are shown in Table 1.
EXAMPLE 10
The same procedure as in Example 1 was repeated to give sample (10) of acid-type polymaleic acid, except that the amount of iron (III) ammonium sulfate dodecahydrate was changed to 0.040 parts and it was added dropwise in the form of 0.40% aqueous solution (10 parts) simultaneously with hydrogen peroxide. The sample was analyzed in the same way as in Example 1. The results are shown in Table 1.
EXAMPLES 11 TO 14
The same procedure as in Example 1 was repeated to give samples (11) to (14) of acid-type polymaleic acid, except that the iron (III) ammonium sulfate dodecahydrate was replaced by iron (II) ammonium sulfate hexahydrate in an amount shown in Table 1 and the amount of hydrogen peroxide was changed as shown in Table 1. The samples were analyzed in the same way as in Example 1. The results are shown in Table 1.
EXAMPLES 15 TO 20
The same procedure as in Example 1 was repeated to give samples (15) to (20) of acid-type polymaleic acid, except that the iron (III) ammonium sulfate dodecahydrate was replaced by vanadyl sulfate in an amount shown in Table 1 and the amount of hydrogen peroxide was changed as shown in Table 1. The samples were analyzed in the same way as in Example 1. The results are shown in Table 1.
EXAMPLES 21 TO 23
The same procedure as in Example 1 was repeated to give samples (21) to (23) of acid-type polymaleic acid, except that the iron (III) ammonium sulfate dodecahydrate was replaced by copper (II) ammonium sulfate pentahydrate in an amount shown in Table 1 and the amount of hydrogen peroxide was changed as shown in Table 1. The samples were analyzed in the same way as in Example 1. The results are shown in Table 1.
EXAMPLE 24
The same procedure as in Example 1 was repeated to give sample (24) of acid-type polymaleic acid, except that the amount of iron (III) ammonium sulfate dodecahydrate was changed to 0.9 parts (equivalent to 450 ppm of Fe.sup.3+ based on the amount of maleic acid charged). The sample was analyzed in the same way as in Example 1. The results are shown in Table 1.
TABLE 1__________________________________________________________________________ Molar ratio Amount of Amount of Acid-type of NaOH Amount of Metal ion hydrogen residualEx- maleic acid to maleic metal ion (Method of peroxide maleic D valueample sample acid*.sup.1 (ppm)*.sup.2 addition)*.sup.3 (g)*.sup.4 acid (%)*.sup.5 M.sub.W M.sub.N (M.sub.W /M.sub.N)__________________________________________________________________________ 1 (1) 0 (0.3) 5 Fe.sup.3+ (1) 28.9 3.0 1200 950 1.26 2 (2) 0 (0.3) 1 Fe.sup.3+ (1) 28.9 8.5 1220 960 1.27 3 (3) 0 (0.3) 20 Fe.sup.3+ (1) 28.9 2.5 1200 960 1.25 4 (4) 0 (0.3) 60 Fe.sup.3+ (1) 28.9 2.5 1250 940 1.33 5 (5) 0 (0.3) 300 Fe.sup.3+ (1) 28.9 2.5 1920 1380 1.39 6 (6) 0 (0.3) 5 Fe.sup.3+ (1) 12.0 10.0 1210 950 1.27 7 (7) 0 (0.3) 60 Fe.sup. 3+ (1) 12.0 5.0 1280 950 1.34 8 (8) 0 (0.3) 1 Fe.sup.3+ (1) 80.0 3.5 930 650 1.43 9 (9) 0 (0.3) 5 Fe.sup.3+ (1) 80.0 0.5 1010 740 1.3610 (10) 0 (0.3) 20 Fe.sup.3+ (2) 28.9 2.8 1200 960 1.2511 (11) 0 (0.3) 5 Fe.sup.2+ (1) 28.9 3.5 1200 950 1.2612 (12) 0 (0.3) 1 Fe.sup.2+ (1) 28.9 10.0 1220 960 1.2713 (13) 0 (0.3) 20 Fe.sup.2+ (1) 28.9 3.0 1200 960 1.2514 (14) 0 (0.3) 300 Fe.sup.2+ (1) 28.9 2.9 2000 1400 1.4315 (15) 0 (0.3) 1 VO.sup.2+ (1) 28.9 5.5 1200 960 1.2516 (16) 0 (0.3) 20 VO.sup.2+ (1) 28.9 0.5 1200 960 1.2517 (17) 0 (0.3) 60 VO.sup.2+ (1) 28.9 0.5 1220 950 1.2818 (18) 0 (0.3) 200 VO.sup.2+ (1) 28.9 0.5 1780 1300 1.3719 (19) 0 (0.3) 20 VO.sup.2+ (1) 12.0 3.5 1210 960 1.2620 (20) 0 (0.3) 20 VO.sup.2+ (1) 60.0 0.2 1080 820 1.3221 (21) 0 (0.3) 1 Cu.sup.2+ (1) 28.9 12.0 1220 950 1.2822 (22) 0 (0.3) 20 Cu.sup.2+ (1) 28.9 5.5 1210 950 1.2723 (23) 0 (0.3) 200 Cu.sup.2+ (1) 28.9 3.5 1890 1350 1.4024 (24) 0 (0.3) 450 Fe.sup.3+ (1) 28.9 3.8 2980 2000 1.49__________________________________________________________________________ *.sup.1 Represents the degree of neutralization of the monomer charged. The parenthesized number denotes the pH at the time of polymerization (measured without dilution at 80.degree. C.). *.sup.2 ppm (as metal ion) based on the amount of maleic acid. *.sup.3 (1) indicates that the metal ion was added all at once at the initial stage of polymerization, and (2) indicates that the metal ion was added dropwise continuously. *.sup.4 g per mol of maleic acid. *.sup.5 % based on the amount of maleic acid charged.
It is noted from Table 1 that the acid-type polymaleic acid obtained by the process of the present invention has a number-average molecular weight of 300-5000, preferably 400-3000, and a D-value lower than 2.5, preferably 2.0, which is defined by M.sub.W /M.sub.N, where M.sub.W is a weight-average molecular weight and M.sub.N is a number-average molecular weight. The weight-average molecular weight and number-average molecular weight are those values which are obtained when polyethylene glycol was used as the reference sample for molecular weight in gel permeation chromatography.
COMPARATIVE EXAMPLE 1
The same procedure as in Example 1 was repeated to give comparative sample (1) of polymaleic acid, except that the iron (III) ammonium sulfate dodecahydrate was replaced by iron (II) ammonium Sulfate hexahydrate in an amount of 8.2 parts (equivalent to 5000 ppm of Fe.sup.2+ based on the amount of maleic acid charged). The sample was analyzed in the same way as in Example 1. The results are shown in Table 2.
COMPARATIVE EXAMPLE 2
The same procedure as in Example 1 was repeated to give comparative sample (2) of polymaleic acid, except that the amount of iron (III) ammonium sulfate dodecahydrate was changed to 10.0 parts (equivalent to 5000 ppm of Fe.sup.3+ based on the amount of maleic acid charged). The sample was analyzed in the same way as in Example 1. The results are shown in Table 2.
COMPARATIVE EXAMPLES 3 AND 4
The same procedure as in Example 1 was repeated to give comparative samples (3) and (4) of polymaleic acid, except that iron (III) ammonium sulfate dodecahydrate was not used at all and the amount of 60% hydrogen peroxide was changed as shown in Table 2. The sample was analyzed in the same way as in Example 1. The results are shown in Table 2.
COMPARATIVE EXAMPLE 5
The same procedure as in Example 1 was repeated to give comparative sample (5) of polymaleate, except that iron (III) ammonium sulfate dodecahydrate was not used at all and maleic acid was charged together with 167 parts of 48% aqueous solution of sodium hydroxide so that 50 mol % of carboxyl groups in maleic acid was neutralized. The sample was analyzed in the same way as in Example 1. The results are shown in Table 2.
COMPARATIVE EXAMPLE 6
The same procedure as in Comparative Example 5 was repeated to give comparative sample (6) of polymaleate, except that iron (II) ammonium sulfate hexahydrate was added in an amount of 0.0082 parts (equivalent to 5 ppm of Fe.sup.2+ based on the amount of maleic acid charged). The sample was analyzed in the same way as in Example 1. The results are shown in Table 2.
COMPARATIVE EXAMPLE 7
The same procedure as in Comparative Example 5 was repeated to give comparative sample (7) of polymaleate, except that iron (III) ammonium sulfate dodecahydrate was added in an amount of 0.010 parts (equivalent to 5 ppm of Fe.sup.3+ based on the amount of maleic acid charged). The sample was analyzed in the same way as in Example 1. The results are shown in Table 2.
COMPARATIVE EXAMPLE 8
A flask equipped with a thermometer, stirrer, dropping funnel, nitrogen inlet, and reflux condenser was charged with 196 parts of maleic anhydride and 300 parts of water (to make 232 parts of maleic acid). The resulting aqueous solution was heated with stirring to 60.degree. C. Subsequently, 138 parts of 30% aqueous solution of sodium hydroxide was added and then 140 parts of isopropanol was added. With the system heated to the refluxing temperature, 0.25 parts of 4.98% (1% as Fe.sup.2+) aqueous solution of ferrous sulfate (FeSO.sub.4 .multidot.7H.sub.2 O) was added. Finally, 40 parts of 60% hydrogen peroxide was added dropwise over 6 hours. Heating was continued for another 2 hours, and residual isopropanol was expelled. Thus, there was obtained comparative sample (8) of polymaleate. The sample was analyzed in the same way as in Example 1. The results are shown in Table 2.
COMPARATIVE EXAMPLE 9
The same procedure as in Example 1 was repeated to give comparative sample (9) of polymaleic acid, except that the iron (III) ammonium sulfate dodecahydrate was replaced by vanadyl sulfate in an amount shown in Table 2 and the amount of hydrogen peroxide was changed as shown in Table 2. The sample was analyzed in the same way as in Example 1. The results are shown in Table 2.
COMPARATIVE EXAMPLE 10
The same apparatus as in Example 1 was charged with 196 parts of maleic anhydride, 131 parts of monochlorobenzene was added dropwise over 3 hours, and 65.4 parts of xylene, followed by heating to 140.degree. C. To the system a mixture composed of 65.4 parts of di-t-butyl peroxide, 41 parts of xylene, and 65.4 parts of monochlorobenzene, followed by aging for 3 hours at the boiling point. The solvents were distilled away, and 197 parts of pure water was added for hydrolysis to give comparative sample (10) of polymaleic acid. The sample was analyzed in the same way as in Example 1. The results are shown in Table 2.
TABLE 2__________________________________________________________________________ Comparative Molar ratio Amount of Amount ofCompar- polymaleic of NaOH Amount of Metal ion hydrogen residualative acid (salt) to maleic metal ion (Method of peroxide maleic D valueExample sample acid*.sup.1 (ppm)*.sup.2 addition)*.sup.3 (g)*.sup.4 acid (%)*.sup.5 M.sub.W M.sub.N (M.sub.W /M.sub.N)__________________________________________________________________________1 (1) 0 (0.3) 5000 Fe.sup.2+ (1) 28.9 5.0 3000 1230 2.442 (2) 0 (0.3) 5000 Fe.sup.3+ (1) 28.9 4.7 2480 1210 2.053 (3) 0 (0.3) -- -- 28.9 45.0 1220 960 1.274 (4) 0 (0.3) -- -- 60.0 20.0 1220 950 1.285 (5) 1.0 (4.5) -- -- 28.9 6.0 3500 1300 2.706 (6) 1.0 (4.5) 5 Fe.sup.2+ (1) 28.9 2.5 3480 1280 2.707 (7) 1.0 (4.5) 5 Fe.sup.3+ (1) 28.9 4.0 3510 1260 2.788 (8) 0.52 (4.0) 10.8 Fe.sup.2+ (1) 12.0 15.0 3100 1210 2.569 (9) 0 (0.3) 20 VO.sup.2+ (1) 5 30.0 1250 960 1.3010 (10) 0 (-) 0 -- -- 20.0 2050 1220 1.68__________________________________________________________________________ *.sup.1 Represents the degree of neutralization of the monomer charged. The parenthesized number denotes the pH at the time of polymerization (measured without dilution at 80.degree. C.). *.sup.2 ppm (as metal ion) based on the amount of maleic acid. *.sup.3 (1) indicates that the metal ion was added all at once at the initial stage of polymerization. *.sup.4 g per mol of maleic acid. *.sup.5 % based on the amount of maleic acid charged.
EXAMPLES 25 TO 48
The performance of samples (1) to (24) of acid-type polymaleic acid obtained in Examples 1 to 24 as the anti-scale agent was evaluated by the following test. Each sample was dissolved in water to give a 0.02% aqueous solution. Three grams of the solution (equivalent to 3 ppm of the resulting supersaturated aqueous solution) was mixed with 170 g of water and 10 g of 1.56% aqueous solution of calcium chloride dihydrate in a 225-ml glass bottle. To the mixture was further added 10 g of 3% aqueous solution of sodium bicarbonate and 7 g of water to bring the total amount to 200 g. Thus there was obtained a supersaturated aqueous solution containing 530 ppm of calcium carbonate. It was heated at 70.degree. C. for 3 hours. After cooling, precipitates were filtered off through a 0.1 .mu.m membrane filter, and the filtrate was analyzed according to JIS K0101. The scale suppressing ratio (%) was calculated from the following equation. The results are shown in Table 3.
Scale suppressing ratio (%)=(C-B)+(A-B) where,
A : concentration of calcium in the solution before testing;
B : concentration of calcium in the filtrate of the solution containing no antiscale agent; and
C : concentration of calcium in the filtrate after testing
TABLE 3______________________________________ Calcium carbonate scale suppressingExample Polymaleic acid sample used ratio (%)______________________________________25 Acid-type polymaleic acid (1) 81.226 Acid-type polymaleic acid (2) 78.527 Acid-type polymaleic acid (3) 81.528 Acid-type polymaleic acid (4) 79.529 Acid-type polymaleic acid (5) 73.530 Acid-type polymaleic acid (6) 79.131 Acid-type polymaleic acid (7) 81.032 Acid-type polymaleic acid (8) 81.433 Acid-type polymaleic acid (9) 81.634 Acid-type polymaleic acid (10) 79.535 Acid-type polymaleic acid (11) 80.536 Acid-type polymaleic acid (12) 75.737 Acid-type polymaleic acid (13) 80.738 Acid-type polymaleic acid (14) 72.839 Acid-type polymaleic acid (15) 78.840 Acid-type polymaleic acid (16) 85.341 Acid-type polymaleic acid (17) 84.142 Acid-type polymaleic acid (18) 73.543 Acid-type polymaleic acid (19) 82.044 Acid-type polymaleic acid (20) 84.545 Acid-type polymaleic acid (21) 75.146 Acid-type polymaleic acid (22) 79.847 Acid-type polymaleic acid (23) 73.048 Acid-type polymaleic acid (24) 75.3______________________________________
COMPARATIVE EXAMPLES 11 TO 20
The performance of comparative samples (1) to (10) of polymaleic acid (salt) obtained in Comparative Examples 1 to 10 as the anitscale agent was evaluated in the same manner as in Examples 24 to 48. The results are shown in Table 4.
TABLE 4______________________________________ CalciumCompar- carbonateative scale suppressingExample Polymaleic acid (salt) sample used ratio (%)______________________________________11 Comparative polymaleic acid (1) 60.012 Comparative polymaleic acid (2) 61.213 Comparative polymaleic acid (3) 59.514 Comparative polymaleic acid (4) 65.015 Comparative polymaleate (5) 41.016 Comparative polymaleate (6) 43.017 Comparative polymaleate (7) 42.018 Comparative polymaleate (8) 55.919 Comparative polymaleic acid (9) 66.820 Comparative polymaleic acid (10) 68.2______________________________________
COMPARATIVE EXAMPLES 49 TO 72
The performance of samples (1) to (24) of acid-type polymaleic acid obtained in Examples 1 to 24 as the detergent builder was evaluated by the following test. Each sample (10 mg in terms of solids) was added to 50 ml of aqueous solution containing 10.sup.-3 mol/L of calcium chloride. The amount of calcium ions sequestered by the sample was determined by means of an ion analyzer (Model 701, made by Orion Co., Ltd.) and a calcium ion electrode. The chelating ability of the acid-type polymaleic acid was calculated from the following equation. The results are shown in Table 5. ##EQU1##
TABLE 5______________________________________ ChelatingEx- abilityample Acid-type polymaleic acid [mg .multidot. CaCO.sub.3 /g]______________________________________49 Acid-type polymaleic acid (1) 23050 Acid-type polymaleic acid (2) 22051 Acid-type polymaleic acid (3) 23152 Acid-type polymaleic acid (4) 22953 Acid-type polymaleic acid (5) 22254 Acid-type polymaleic acid (6) 22055 Acid-type polymaleic acid (7) 22456 Acid-type polymaleic acid (8) 22157 Acid-type polymaleic acid (9) 23058 Acid-type polymaleic acid (10) 23159 Acid-type polymaleic acid (11) 22360 Acid-type polymaleic acid (12) 21861 Acid-type polymaleic acid (13) 22462 Acid-type polymaleic acid (14) 22063 Acid-type polymaleic acid (15) 23664 Acid-type polymaleic acid (16) 23865 Acid-type polymaleic acid (17) 23466 Acid-type polymaleic acid (18) 23967 Acid-type polymaleic acid (19) 23068 Acid-type polymaleic acid (20) 23869 Acid-type polymaleic acid (21) 21270 Acid-type polymaleic acid (22) 22871 Acid-type polymaleic acid (23) 22572 Acid-type polymaleic acid (24) 228______________________________________
COMPARATIVE EXAMPLES 21 TO 30
The performance of samples (1) to (10) of comparative polymaleic acid (salt) obtained in Comparative Examples 1 to 10 as the detergent builder was evaluated in the same manner as in Examples 49 to 72. The results are shown in Table 6.
TABLE 6______________________________________Compar- Chelatingative abilityExample Comparative polymaleic acid (salt) [mg .multidot. CaCO.sub.3 /g]______________________________________21 Comparative polymaleic acid (1) 17322 Comparative polymaleic acid (2) 16823 Comparative polymaleic acid (3) 9524 Comparative polymaleic acid (4) 11325 Comparative polymaleate (5) 15026 Comparative polymaleate (6) 16827 Comparative polymaleate (7) 16528 Comparative polymaleate (8) 17029 Comparative polymaleic acid (9) 13230 Comparative polymaleic acid (10) 180______________________________________
The acid-type polymaleic acid (1) obtained in Example 1 was examined by .sup.13 C-NMR The NMR. chart is shown in FIG. 1. The chart shows a peak at 30-40 ppm which indicates the carbon of CH.sub.2. This suggests that the acid-type polymaleic acid (1) contains the acrylic acid structure originating from the decarbonization that took place at the time of polymerization.
EXAMPLE 73
A 1-liter four-neck flask equipped with a thermometer, stirrer, and reflux condenser was charged with 196 parts of maleic anhydride, 75.1 parts of water (to make 232 parts of maleic acid), and 0.0153 parts of vanadyl sulfate dihydrate (equivalent to 20 ppm of VO.sup.2+ based on the amount of monomer component). The resulting aqueous solution was heated with stirring to the boiling point under normal pressure. Then, 76.7 parts of 60% hydrogen peroxide (equivalent to 20 g per mol of the monomer component) and 26 parts of 3-methyl-3-buten-1-ol (isoprenol) were added dropwise with stirring continuously over 3 hours, during which polymerization proceeded Stirring was continued for another 1 hour at the boiling point of the system. After the completion of polymerization, there was obtained sample (73) of acid-type maleic acid copolymer containing 71% solids. The polymerization was carried out at pH 0.3
The thus obtained sample (73) was tested for molecular weight and molecular-weight distribution by gel permeation chromatography under the same conditions as mentioned above. The results are shown in Table 7.
The biodegradability of sample (73) was calculated from the following formula.
X=(D-E)+(F-G).times.100
X : ratio (%) of biodegradation that took place in 5 days
D : biological oxygen demand (BOD 5) by the acid-type maleic acid copolymer for 5 days. (*1)
E : biological oxygen demand by the residual monomer for 5 days. (*2)
F : theoretical oxygen demand by the acid-type maleic acid copolymer (*3)
G : theoretical oxygen demand by the residual monomer
(*1) Measured according to JIS K-0102.
(*2) The amount of the residual monomer was determined by gel permeation chromatography and gas chromatography. The biological oxygen demand by each monomer component was measured according to JIS K-0102, and the biological oxygen demand by the total amount of the residual monomers was calculated.
(*3) The amount of oxygen necessary for complete oxidation was calculated from the data of elemental analysis of the acid-type maleic acid copolymer.
EXAMPLES 74 AND 75
The same procedure as in Example 73 was repeated to give samples (74) and (75) of acid-type maleic acid copolymer, except that the amount of vanadyl sulfate dihydrate was changed as shown in Table 7. The samples were analyzed in the same way as in Example 73. The results are shown in Table 7.
EXAMPLE 76
The same procedure as in Example 73 was repeated to give sample (76) of acid-type maleic acid copolymer, except that the vanadyl sulfate dihydrate was replaced by 10 parts of 0.45% aqueous solution of iron (II;) ammonium sulfate dodecahydrate (equivalent to 20 ppm of Fe.sup.3+ based on the amount of monomer component), and it was added dropwise together with hydrogen peroxide. The sample was analyzed in the same way as in Example 73. The results are shown in Table 7.
EXAMPLE 77
The same procedure as in Example 73 was repeated to give sample (77) of acid-type maleic acid copolymer, except that the vanadyl sulfate dihydrate was replaced by 0.045 parts of iron (III) ammonium sulfate dodecahydrate (equivalent to 20 ppm of Fe.sup.3+ based on the amount of monomer component). The sample was analyzed in the same way as in Example 73. The results are shown in Table 7.
EXAMPLE 78
The same procedure as in Example 73 was repeated to give sample (78) of acid-type maleic acid copolymer, except that the vanadyl sulfate dihydrate was replaced by 0.013 parts of anhydrous copper (II) sulfate (equivalent to 20 ppm of Cu.sup.2+ based on the amount of monomer component). The sample was analyzed in the same way as in Example 73. The results are shown in Table 7.
EXAMPLES 79 AND 80
The same procedure as in Example 73 was repeated to give samples (79) and (80) of acid-type maleic acid copolymer, except that the vanadyl sulfate dihydrate was replaced by 0.045 parts of iron (III) ammonium sulfate dodecahydrate and the amount of hydrogen peroxide was changed as shown in Table 7. The samples were analyzed in the same way as in Example 73. The results are shown in Table 7.
EXAMPLE 81
The same procedure as in Example 73 was repeated to give sample (81) of acid-type maleic acid copolymer, except that 0.005 g of 1-hydroxyethylidene-1,1-diphosphonic acid (as a chelating agent) was added in the initial stage of charging. The sample was analyzed in the same way as in Example 73. The results are shown in Table 7.
EXAMPLE 82
The same procedure as in Example 73 was repeated to give sample (82) of acid-type maleic acid copolymer, except that hydrogen peroxide was added in the following manner. At first, dropping was continued for 1.5 hours; dropping was suspended for 60 minutes, during which the reaction temperature was kept at the boiling point (110.degree. C.); and dropping was resumed and continued for 1.5 hours. The sample was analyzed in the same way as in Example 73. The results are shown in Table 7.
EXAMPLES 83 AND 84
The same procedure as in Example 73 was repeated to give samples (83) and (84) of acid-type maleic acid copolymer, except that the vanadyl sulfate dihydrate was replaced by 0.045 parts of iron (III) ammonium sulfate dodecahydrate and the amounts of monomer and hydrogen peroxide were changed as shown in Table 7. The samples were analyzed in the same way as in Example 73. The results are shown in Table 7.
EXAMPLES 85 AND 99
The same procedure as in Example 73 was repeated to give samples (85) to (99) of acid-type maleic acid copolymer, except that the kind and amount of monomer and metal ion were changed as shown in Table 7. The samples were analyzed in the same way as in Example 73. The results are shown in Table 7.
TABLE 7__________________________________________________________________________(Part 1) Acid-type Metal ion Amount of maleic acid Other water-soluble Ratio of (A)/(B) (Method of metal ionExample copolymer unsaturated monomer (B) (by weight)*.sup.1 addition)*.sup.2 (ppm)*.sup.3__________________________________________________________________________73 (73) Isoprenol 90/10 VO.sup.2+ (1) 2074 (74) Isoprenol 90/10 VO.sup.2+ (1) 275 (75) Isoprenol 90/10 VO.sup.2+ (1) 40076 (76) Isoprenol 90/10 Fe.sup.3+ (2) 2077 (77) Isoprenol 90/10 Fe.sup.3+ (1) 2078 (78) Isoprenol 90/10 Cu.sup.2+ (1) 2079 (79) Isoprenol 90/10 Fe.sup.3+ (1) 2080 (80) Isoprenol 90/10 Fe.sup.3+ (1) 2081 (81) Isoprenol 90/10 VO.sup.2+ (1) 2082 (82) Isoprenol 90/10 VO.sup.2+ (1) 2083 (83) Isoprenol 99/1 Fe.sup.3+ (1) 2084 (84) Isoprenol 50/50 Fe.sup.3+ (1) 2085 (85) Isoprenol EO-5 mol adduct 90/10 VO.sup.2+ (1) 2086 (86) Isoprenol EO-5 mol adduct 90/10 Fe.sup.3+ (1) 2087 (87) Isoprenol EO-5 mol adduct 90/10 Cu.sup.2+ (1) 2088 (88) Glycerol monoallyl ether 90/10 Fe.sup.3+ (1) 2089 (89) Glycerol monoallyl ether 90/10 Fe.sup.2+ (1) 20 EO-5 mol adduct90 (90) Acrylic acid 90/10 VO.sup.2+ (1) 2091 (91) Acrylic acid 70/30 Fe.sup.3+ (1) 2092 (92) Acrylic acid 70/30 Cu.sup.2+ (1) 2093 (93) Methacrylic acid 90/10 VO.sup.2+ (1) 2094 (94) 3-allyloxy-2-hydroxy- 98/2 VO.sup.2+ (1) 20 propanesulfonic acid95 (95) 3-allyloxy-2-hydroxy- 90/10 Fe.sup.3+ (1) 20 propanesulfonic acid96 (96) 3-allyloxy-2-hydroxy- 90/10 Cu.sup.2+ (1) 20 propanesulfonic acid97 (97) Vinyl acetate 90/10 VO.sup.2+ (1) 2098 (98) Vinyl acetate 80/20 Fe.sup.3+ (1) 2099 (99) Vinyl acetate 80/20 Cu.sup.2+ (1) 20__________________________________________________________________________ *.sup.1 (A): maleic acid, (B): other watersoluble unsaturated monomer. *.sup.2 (1) indicates that the metal ion was added all at once at the initial stage of polymerization, and (2) indicates that the metal ion was added dropwise continuously. *.sup.3 ppm (as metal ion) based on the amount of monomer components.
(Part 2) Amount of Amount of pH at polymeri- Ratio of hydrogen residual zation time biode-Ex- peroxide monomer (undiluted, D value gradationample (g/mol monomer) (wt %/monomer) at 80.degree. C.) M.sub.W M.sub.N (M.sub.W /M.sub.N) (%)__________________________________________________________________________73 20 2 0.3 2800 1900 1.47 1774 20 10 0.3 2850 1900 1.50 1075 20 5 0.3 4780 2300 2.08 976 20 7 0.3 2900 1950 1.49 1677 20 5 0.4 2800 1850 1.51 1778 20 7 0.2 2750 1800 1.53 1679 80 2 0.3 1680 1100 1.53 1480 8 10 0.2 2750 1800 1.53 1081 20 1.5*.sup.1 0.3 2800 1900 1.47 1782 20 1.0*.sup.2 0.3 2700 1800 1.50 1783 80 3 0.2 1090 690 1.58 1584 20 10 0.3 3610 2100 1.72 1085 20 2 0.3 2600 1900 1.36 1786 20 6 0.3 2650 1900 1.40 1787 20 8 0.3 2600 1800 1.44 1688 20 3 0.3 2800 1950 1.44 1689 20 5 0.3 2750 1800 1.53 1590 20 1.5 0.2 2900 1900 1.52 1691 20 2 0.2 3950 2500 1.58 1792 20 5 0.2 4090 3100 1.61 1593 20 2 0.2 2800 1900 1.47 1594 20 2 0.2 2120 1210 1.75 1595 20 3 0.2 2600 1500 1.73 1696 20 7 0.2 2550 1500 1.70 1597 20 3 0.2 2680 1850 1.45 1798 20 5 0.2 2720 1890 1.44 2099 20 8 0.2 2710 1840 1.47 16__________________________________________________________________________ *.sup.1 A chelating agent was added. *.sup.2 The addition of hydrogen peroxide was temporarily suspended.
COMPARATIVE EXAMPLE 31
The same procedure as in Example 73 was repeated to give comparative sample (31) of maleic acid copolymer, except that 166.6 parts of 48% aqueous solution of sodium hydroxide (required to neutralize half the carboxylic acid) was added. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 32
The same procedure as in Example 73 was repeated to give comparative sample (32) of acid-type maleic acid copolymer, except that the vanadyl sulfate dihydrate was not used. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 33
The same procedure as in Example 73 was repeated to give comparative sample (33) of maleic acid copolymer, except that the amount of vanadyl sulfate dihydrate was changed to 2.30 parts. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLES 34 TO 37
The same procedure as in Example 73 was repeated to give comparative samples (34) to (37) of maleic acid copolymer, except that the vanadyl sulfate dihydrate was replaced by the metal ion as shown in Table 8. The samples were analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLES 38 TO 44
The same procedure as in Example 73 was repeated to give comparative samples (38) to (41) of maleic acid copolymer, except that the hydrogen peroxide as replaced by the peroxide as shown in Table 8. The samples were analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 42
The same procedure as in Example 73 was repeated to give comparative sample (42) of maleic acid copolymer, except that 26.0 parts of acrylic acid was used as the water-soluble unsaturated monomer, the vanadyl sulfate was not used, and the amount of the hydrogen peroxide was changed as shown in Table 8. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 43
The same procedure as in Example 73 was repeated to give comparative sample (43) of maleic acid copolymer salt, except that 26.0 parts of acrylic acid was used as the water-soluble unsaturated monomer, 181.7 parts of 48% aqueous solution of sodium hydroxide (required to neutralize half the carboxylic acid) was added, and the amount of the hydrogen peroxide was changed as shown in Table 8. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 44
The same procedure as in Example 73 was repeated to give comparative sample (44) of maleic acid copolymer salt, except that 26.0 parts of acrylic acid was used as the water-soluble unsaturated monomer, 2.30 parts of vanadyl sulfate dihydrate (3000 ppm (as VO.sup.2+) of the monomer component) was used, and the amount of the hydrogen peroxide was changed as shown in Table 8. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 45
The same procedure as in Example 73 was repeated to give comparative sample (45) of maleic acid copolymer, except that 26.0 parts of acrylic acid was used as the water-soluble unsaturated monomer, the vanadyl sulfate dihydrate was replaced by iron (III) ammonium sulfate dodecahydrate in an amount of 6.69 parts (3000 ppm (as Fe.sup.3+) of the monomer component), and the amount of the hydrogen peroxide was changed as shown in Table 8. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 46
The same procedure as in Example 73 was repeated to give comparative sample (46) of maleic acid copolymer, except that the amount of the 60% hydrogen peroxide was changed to 19.2 g (equivalent to 5 g per mol of the monomer component). The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 47
The same apparatus as in Example 73 was charged with 196 parts of maleic anhydride, 131 parts of monochlorobenzene, and 65.4 parts of xylene, followed by heating to 140.degree. C. To the system was added dropwise over 3 hours a mixture composed of 65.4 parts of di-t-butyl peroxide, 41 parts of xylene, and 65.4 parts of monochlorobenzene and then 26 parts of acrylic acid, followed by aging for 3 hours at the boiling point. The solvents were distilled away, and 197 parts of pure water was added for hydrolysis to give comparative sample (47) of maleic acid copolymer. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 48
A flask equipped with a thermometer, stirrer, dropping funnel, nitrogen inlet, and reflux condenser was charged with 196 parts of maleic anhydride and 300 parts of water (to make 232 parts of maleic acid). The resulting aqueous solution was heated with stirring to 60.degree. C. Subsequently, 138 parts of 30% aqueous solution of sodium hydroxide was added and then 140 parts of isopropanol was added. Further, 26 parts of acrylic acid was added. With the system heated to the refluxing temperature, 0.25 parts of 4.98% (1% as Fe.sup.2+) aqueous solution of ferrous sulfate (FeSO.sub.4 .multidot.7H.sub.2 O) was added. Finally, 40 parts of 60% hydrogen peroxide was added dropwise over 6 hours. Heating was continued for another 2 hours, and residual isopropanol was expelled. Thus, there was obtained comparative sample (48) of maleic acid copolymer salt. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 49
The same polymerization vessel as in Example 73 was charged with 77.3 parts of 1-allyloxy-2,3-dihyroxypropane (glycerol monoallyl ether), 116 parts of maleic acid, 166.6 parts of 48% aqueous solution of sodium hydroxide, and 157.4 parts of water. The resulting aqueous solution was heated with stirring to the boiling point of the system. Then, 100 parts of 10% aqueous solution of ammonium persulfate was added dropwise from the dropping funnel over 2 hours, during which the polymerization temperature was kept at the boiling point of the system. The system was left at the same temperature for 30 minutes to complete the polymerization. Thus there was obtained comparative sample (49) of maleic acid copolymer salt. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 50
The same polymerization vessel as in Example 73 was charged with 145 parts of maleic acid, 208.3 parts of 48% aqueous solution of sodium hydroxide, and 156.7 parts of water. With the atmosphere in the vessel replaced with nitrogen, the system was heated to 95.degree. C. with stirring. Then, 35.8 parts of 50% aqueous solution of sodium 3-allyloxy-2-hydroxypropanesulfonate (16.1 parts as 3-allyloxy-2-hydroxypropanesulfonic acid) and 50 parts of 10% aqueous solution of ammonium persulfate were added dropwise from separate dropping nozzles over 4 hours. During dropping, the copolymerization temperature was kept at 95.degree. C. The system was kept at 95.degree. C. for 30 minutes to complete copolymerization. Thus, there was obtained comparative sample (50) of maleic acid copolymer salt. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
COMPARATIVE EXAMPLE 51
The same procedure as in Example 73 was repeated to give comparative sample (51) of maleic acid copolymer, except that the amounts of monomer component, hydrogen peroxide, and metal ion were changed as shown in Table 8. The sample was analyzed in the same way as in Example 73. The results are shown in Table 8.
TABLE 8__________________________________________________________________________(Part 1) Comparative Degree ofCompar- maleic acid neutrali- Amount ofative copolymer Other water-soluble Ratio of (A)/(B) zation Metal metal ionExample (salt) unsaturated monomer (B) (by weight)*.sup.1 (%) ion*.sup.2 (ppm)*.sup.3__________________________________________________________________________31 (31) Isoprenol 90/10 50 VO.sup.2+ 2032 (32) Isoprenol 90/10 0 -- 033 (33) Isoprenol 90/10 0 VO.sup.2+ 300034 (34) Isoprenol 90/10 0 Zn.sup.2+ 5035 (35) Isoprenol 90/10 0 Ni.sup.2+ 5036 (36) Isoprenol 90/10 0 Mn.sup.2+ 5037 (37) Isoprenol 90/10 0 Co.sup.2+ 5038 (38) Isoprenol 90/10 0 VO.sup.2+ 2039 (39) Isoprenol 90/10 0 VO.sup.2+ 2040 (40) Isoprenol 90/10 0 VO.sup.2+ 2041 (41) Isoprenol 90/10 0 VO.sup.2+ 2042 (42) Acrylic acid 90/10 0 -- 043 (43) Acrylic acid 90/10 50 VO.sup.2+ 2044 (44) Acrylic acid 90/10 0 VO.sup.2+ 300045 (45) Acrylic acid 90/10 0 Fe.sup.2+ 300046 (46) Isoprenol 90/10 0 VO.sup.2+ 2047 (47) Acrylic acid 90/10 0 -- 048 (48) Acrylic acid 90/10 23.7 Fe.sup.2+ 9.749 (49) Glycerol monoallyl ether 60/40 100 -- 050 (50) 3-allyloxy-2-hydroxy 90/10 100 -- 0 propanesulfonic acid51 (51) Isoprenol 30/70 0 VO.sup.2+ 20__________________________________________________________________________ *.sup.1 (A): maleic acid, (B): other watersoluble unsaturated monomer. *.sup.2 added all at once at the initial stage. *.sup.3 ppm (as metal ion) based on the amount of monomer components.
(Part 2) Amount of pH at polymeri- Ratio ofCompar- Amount of residual zation time biode-ative initiator monomer (undiluted, D value gradationExample (g/mol monomer) (wt %/monomer) at 80.degree. C.) M.sub.W M.sub.N (M.sub.W /M.sub.N) (%)__________________________________________________________________________31 Hydrogen peroxide (20) 2 4.5 5600 1900 2.95 432 Hydrogen peroxide (20) 45 0.5 2800 1900 1.47 533 Hydrogen peroxide (20) 10 0.3 5100 1950 2.62 434 Hydrogen peroxide (20) 18 0.3 2700 1900 1.42 335 Hydrogen peroxide (20) 19 0.3 2750 1800 1.53 436 Hydrogen peroxide (20) 17 0.3 2700 1800 1.50 337 Hydrogen peroxide (20) 18 0.3 2800 1800 1.56 238 Sodium persulfate (20) 87 1.2 3100 1800 1.72 339 Ammonium persulfate (20) 85 1.1 3000 1900 1.58 340 t-butylhydroperoxide (20) 70 0.5 2700 1900 1.42 341 Cumene hydroperoxide (20) 73 0.5 2700 1900 1.42 442 Hydrogen peroxide (20) 48 0.3 2800 1800 1.56 543 Hydrogen peroxide (20) 3 4.2 5900 2000 2.95 444 Hydrogen peroxide (20) 10 0.3 4800 1850 2.59 345 Hydrogen peroxide (20) 8 0.4 5200 2000 2.60 346 Hydrogen peroxide (5) 20 0.3 2900 1800 1.61 247 di-t-butyl peroxide (27.7) 20 -- 4800 1800 2.67 348 Hydrogen peroxide (10.2) 25 4.0 4850 1000 4.85 349 Ammonium persulfate (6.3) 12 8.5 5860 1850 3.17 350 Ammonium persulfate (3.75) 6 8.5 5530 1900 2.91 251 Hydrogen peroxide (20) 30 0.3 2500 1700 1.47 5__________________________________________________________________________
EXAMPLES 100 TO 126
The performance of samples (73) to (99) of acid-type maleic acid copolymer obtained in Examples 73 to 99 as the antiscale agent was evaluated in the same manner as in Examples 25 to 48. The results are shown in Table 9.
TABLE 9______________________________________ Calcium carbonateEx- scale suppressingample Acid-type maleic acid copolymer ratio (%)______________________________________100 Acid-type maleic acid copolymer (73) 87.0101 Acid-type maleic acid copolymer (74) 81.0102 Acid-type maleic acid copolymer (75) 83.1103 Acid-type maleic acid copolymer (76) 86.1104 Acid-type maleic acid copolymer (77) 84.8105 Acid-type maleic acid copolymer (78) 83106 Acid-type maleic acid copolymer (79) 85107 Acid-type maleic acid copolymer (80) 79.3108 Acid-type maleic acid copolymer (81) 85.1109 Acid-type maleic acid copolymer (82) 84.6110 Acid-type maleic acid copolymer (83) 86.0111 Acid-type maleic acid copolymer (84) 85.5112 Acid-type maleic acid copolymer (85) 87.1113 Acid-type maleic acid copolymer (86) 86.5114 Acid-type maleic acid copolymer (87) 85.1115 Acid-type maleic acid copolymer (88) 86.8116 Acid-type maleic acid copolymer (89) 87.0117 Acid-type maleic acid copolymer (90) 86.5118 Acid-type maleic acid copolymer (91) 85.1119 Acid-type maleic acid copolymer (92) 85.6120 Acid-type maleic acid copolymer (93) 86.3121 Acid-type maleic acid copolymer (94) 84.9122 Acid-type maleic acid copolymer (95) 86.9123 Acid-type maleic acid copolymer (96) 87.2124 Acid-type maleic acid copolymer (97) 86.1125 Acid-type maleic acid copolymer (98) 85.8126 Acid-type maleic acid copolymer (99) 86.0______________________________________
COMPARATIVE EXAMPLES 52 TO 72
The performance of comparative samples (31) to (51) of maleic acid copolymer (salt) obtained in Comparative Examples 31 to 51 as the antiscale agent was evaluated in the same manner as in Examples 100 to 126. The results are shown in Table 10.
TABLE 10______________________________________Compar- Calcium carbonateative Comparative samples of scale suppressingExample maleic acid copolymer (salt) ratio (%)______________________________________52 Maleic acid copolymer salt (31) 4553 Maleic acid copolymer (32) 3754 Maleic acid copolymer (33) 5155 Maleic acid copolymer (34) 4656 Maleic acid copolymer (35) 4357 Maleic acid copolymer (36) 4458 Maleic acid copolymer (37) 4159 Maleic acid copolymer (38) 4860 Maleic acid copolymer (39) 3961 Maleic acid copolymer (40) 3162 Maleic acid copolymer (41) 3263 Maleic acid copolymer (42) 3564 Maleic acid copolymer salt (43) 4265 Maleic acid copolymer (44) 3966 Maleic acid copolymer (45) 4767 Maleic acid copolymer (46) 5168 Maleic acid copolymer (47) 5369 Maleic acid copolymer salt (48) 5870 Maleic acid copolymer salt (49) 7271 Maleic acid copolymer salt (50) 7672 Maleic acid copolymer (51) 53______________________________________
EXAMPLES 127 TO 153
The performance of samples (73) to (99) of acid-type maleic acid copolymer obtained in Examples 73 to 99 as the detergent builder was evaluated in the same manner as in Examples 49 to 72. The results are shown in Table 11.
TABLE 11______________________________________ ChelatingEx- abilityample Acid-type maleic acid copolymer [mg .multidot. CaCO.sub.3 /g]______________________________________127 Acid-type maleic acid copolymer (73) 245128 Acid-type maleic acid copolymer (74) 246129 Acid-type maleic acid copolymer (75) 248130 Acid-type maleic acid copolymer (76) 252131 Acid-type maleic acid copolymer (77) 242132 Acid-type maleic acid copolymer (78) 253133 Acid-type maleic acid copolymer (79) 244134 Acid-type maleic acid copolymer (80) 247135 Acid-type maleic acid copolymer (81) 240136 Acid-type maleic acid copolymer (82) 241137 Acid-type maleic acid copolymer (83) 242138 Acid-type maleic acid copolymer (84) 253139 Acid-type maleic acid copolymer (85) 249140 Acid-type maleic acid copolymer (86) 241141 Acid-type maleic acid copolymer (87) 255142 Acid-type maleic acid copolymer (88) 246143 Acid-type maleic acid copolymer (89) 242144 Acid-type maleic acid copolymer (90) 248145 Acid-type maleic acid copolymer (91) 245146 Acid-type maleic acid copolymer (92) 247147 Acid-type maleic acid copolymer (93) 244148 Acid-type maleic acid copolymer (94) 241149 Acid-type maleic acid copolymer (95) 243150 Acid-type maleic acid copolymer (96) 249151 Acid-type maleic acid copolymer (97) 246152 Acid-type maleic acid copolymer (98) 243153 Acid-type maleic acid copolymer (99) 242______________________________________
COMPARATIVE EXAMPLES 73 TO 93
The performance of comparative samples (31) to (51) of maleic acid copolymer (salt) obtained in Comparative Examples 31 to 51 as the detergent builder was evaluated in the same manner as in Examples 127 to 153. The results are shown in Table 12.
TABLE 12______________________________________Compar- Chelatingative Comparative samples of abilityExample Maleic acid copolymer (salt) [mg .multidot. CaCO.sub.3 /g]______________________________________73 Maleic acid copolymer salt (31) 18574 Maleic acid copolymer (32) 17675 Maleic acid copolymer (33) 19176 Maleic acid copolymer (34) 12177 Maleic acid copolymer (35) 13578 Maleic acid copolymer (36) 9879 Maleic acid copolymer (37) 11180 Maleic acid copolymer (38) 6381 Maleic acid copolymer (39) 5782 Maleic acid copolymer (40) 7283 Maleic acid copolymer (41) 8184 Maleic acid copolymer (42) 10585 Maleic acid copolymer salt (43) 17586 Maleic acid copolymer (44) 15487 Maleic acid copolymer (45) 16388 Maleic acid copolymer (46) 15289 Maleic acid copolymer (47) 13590 Maleic acid copolymer salt (48) 16491 Maleic acid copolymer salt (49) 18592 Maleic acid copolymer salt (50) 19093 Maleic acid copolymer (51) 121______________________________________

Number	Date	Country	Kind
63-87218	Apr 1988	JPX
63-267181	Oct 1988	JPX

Number	Name	Date
3635915	Gale	Jan 1972
3846383	Uyama et al.	Nov 1974
4314044	Hughes	Feb 1982
4589995	Fukumoto	May 1989
4659793	Yang	Apr 1987
4818795	Denzinger et al.	Apr 1989

Process for producing acid-type maleic acid polymer and water-treating agent and detergent additive containing said polymer

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