Abstract: The present invention is a method of producing a (meth)acrylic acid based water-soluble polymer having a content of groups in neutralized state of not more than 90 mole percent, where the sum total of acid groups and groups in neutralized state contained in the (meth)acrylic acid based water-soluble polymer is taken as 100 mole percent, which comprises a photopolymerization step of polymerizing a monomer component by irradiating near-ultraviolet rays to a reaction mixture, the said reaction mixture comprising the monomer component, a photopolymerization initiator, a chain transfer agent and a polymerization solvent, the said monomer component containing not less than 50 mole percent of a (meth)acrylic acid monomer, with the whole monomer component subjected to polymerization being taken as 100 mole percent, and a concentration of the said monomer component in the reaction mixture at the time of polymerization being 40 to 97% by mass.

Abstract: The present invention provides: an acrylic acid (salt) polymer, which has a low molecular weight and a narrow molecular weight distribution and can display excellent dispersibility, or which has a high molecular weight and a high water solubility; a production process that enables easy production of this polymer; and an acrylic acid (salt) polymer composition comprising this polymer. The acrylic acid (salt) polymer is an acrylic acid (salt) polymer of which not less than 1 weight % of the entirety is accounted for by an acrylic acid (salt) polymer having a specific terminal structure. In addition, the production process for an acrylic acid (salt) polymer comprises the step of carrying out polymerization of a monomer component including an acrylic acid (salt), wherein an acrylic acid (salt) having a furfural content of 200 to 400 weight ppm is used as at least a portion of the acrylic acid (salt) in an amount of not smaller than 10 weight % of the entire monomer component.

Abstract: The present invention provides: a production process that enables to keep foaming state within a constant level and to obtain a polymer with good productivity and reproducibility with a practical plant by defining an appropriate vapor velocity from a weight-average molecular weight of the polymer that is finally intended to obtain; and a polymerization apparatus therefor. A production apparatus for producing a polymer, which comprises a reactor 1 in order to produce the polymer, a stirrer 2 in order to stir a reaction solution in the reactor 1, and a condenser 3 so that a vaporized reaction solution can be cooled and returned to the reactor 1, and further comprises a vapor velocity measuring means of monitoring a vapor velocity in the condenser, and an vapor velocity adjusting means of adjusting the vapor velocity, is used. Then, the vapor velocity is adjusted in the range of 0.001 to 0.

Abstract: The present invention provides: an acrylic acid (salt) polymer, which has a low molecular weight and a narrow molecular weight distribution and can display excellent dispersibility, or which has a high molecular weight and a high water solubility; a production process that enables easy production of this polymer; and an acrylic acid (salt) polymer composition comprising this polymer. The acrylic acid (salt) polymer is an acrylic acid (salt) polymer of which not less than 1 weight % of the entirety is accounted for by an acrylic acid (salt) polymer having a specific terminal structure. In addition, the production process for an acrylic acid (salt) polymer comprises the step of carrying out polymerization of a monomer component including an acrylic acid (salt), wherein an acrylic acid (salt) having a furfural content of 200 to 400 weight ppm is used as at least a portion of the acrylic acid (salt) in an amount of not smaller than 10 weight % of the entire monomer component.

Abstract: The present invention provides a detergent builder and a production process therefor, which detergent builder comprises a polymer that has a narrow molecular weight distribution and is excellent both in the gelation resistance and the chelating ability, and further, the invention provides a polymer which is favorably used also for purposes other than detergent builders. The detergent builder comprises a poly(meth)acrylic acid (or salt) polymer which gives a product of 18,000 or more from the gelation resistance and the chelating ability. To produce this detergent builder, the ratio by weight of (total amount of monomer component, chain transfer agent, and polymerization initiator) to (total amount of aqueous medium) is set in the range of 46:54˜66:34, and 10% or more of the aqueous medium and 0˜50% (preferably 1˜50%) of the chain transfer agent are beforehand charged into a reactor, and the polymerization is carried out at a reaction temperature of 50˜120 ° C.

Abstract: Inexpensive absorbing agent and method for readily and satisfactorily collecting and removing a surfactant from a solution, such as a surfactant-containing liquid waste, are provided. The absorbing agent includes, for example, a crosslinked polymer having a polyoxyalkylene chain. The surfactant is absorbed by bringing the above-arranged absorbing agent into contact with the solution. A particularly preferable crosslinked polymer is produced by crosslinking polyalkylene glycol or polymerizing a monomeric component including a monomer based on (meta)acrylic ester expressed by General Formula below:CH.sub.2 .dbd.CR--CO--(X.sup.1).sub.n --Y.sup.1where R is a hydrogen atom or a methyl group, X.sup.1 is an oxyalkylene group having up to 5 carbon atoms, Y.sup.1 is a hydrogen atom, an alkoxy group having up to 5 carbon atoms, a phenoxy group, or an oxyalkylphenyl group having up to 3 alkyl groups each having up to 9 carbon atoms as a substitutional group, and n is a positive number ranging from 3-100 in average.

Abstract: This invention provides a drilling fluid containing additives composed of copolymers which are obtainable by an industrially favorable process and superior in heat-resisting property. Even though the additives are used in a relatively small amount, such an amount sufficiently prevents changes in the properties of drilling fluid due to various kinds of hard water components being contained in underground water or cement as well as due to sea water, and the additives are able to display the properties of drilling fluid constantly regardless of presence or absence of salts.Drilling fluid additives of the present invention are composed of a water-soluble copolymer (A) having an average molecular weight of 1,000-50,000. The water soluble copolymer (A) is composed of 40-99.5 mole percent of an unsaturated carboxylic acid monomer (I), as shown in the following general formula (I), and 0.5-60 mole percent of an unsaturated (meth)allylether monomer (II), as shown in the general formula (II).

Abstract: The present invention relates to a process for producing an acid-type polymaleic acid and acid-type maleic acid copolymer and also to the usage of the acid-type polymaleic acid and acid-type maleic acid copolymer produced by this process.According to the process of the present invention, the acid-type polymaleic acid and acid-type maleic acid copolymer, which are superior as a water-treating agent and detergent additive, are produced by polymerization of acid-type monomers in an aqueous solution. The process is simple and yields a polymer having a low molecular weight and a narrow molecular-weight distribution. The process permits one to economically produce the acid-type polymaleic acid and acid-type maleic acid copolymer which has good quality and outstanding performance as a water-treating agent etc. Thus the invention is a great boon to the industrial field of water treatment.

Abstract: A specially defined amount of hydrogen peroxide is used as a polymerization catalyzer; a specially defined amount and a specially defined kind of a polyvalent metal ion is used; and a specially defined amount of an alkaline substance is used, in order to polymerize a monomer component consisting essentially of only maleic acid, or a monomer component composed of maleic acid and another water-soluble ethylenically unsaturated monomer, in a specially defined proportion in water, whereby a maleic acid polymer salt, preferably a copolymer salt, of improved biodegradability is produced. The maleic acid polymer salt obtained is superior in biodegradability, has a low residual monomer content, and is useful as a detergent builder and as a scale inhibitor, etc.

Abstract: A water-soluble copolymer useful for scale inhibitor and pigment dispersant, comprising 50 to 99.5 mol % of repeating units represented by the general formula I: ##STR1## wherein, R.sup.1 denotes a hydrogen atom or methyl group and X a hydrogen atom, alkali metal atom, alkaline earth metal atom, ammonium group, or organic amine group and 50 to 0.5 mol % of repeating units represented by the general formula II: ##STR2## wherein, p denotes an integer of the value of 1 to 4, q and r independently denote 0 or an integer of the value of 0 to 100, R.sup.2 and R.sup.