摘要:
A method for producing a water-absorbent resin having a further reduced odor as compared with a water-absorbent resin obtained by a conventional method as well as a water-absorbent resin produced by the same method, by maintaining the addition rate V from the pouring nozzle for the aqueous solution of the water-soluble ethylenically unsaturated monomer in a polymerization reaction tank not more than 0.30 [min−1], in the first stage polymerization step which is within the step of the conventional method upon performing multi-stages such as two or more stages of reversed-phase suspension polymerizations in a method for producing a water-absorbent resin, and thereby by being able to reduce the amount of the petroleum hydrocarbon dispersion medium remaining in the above water-absorbent resin.
摘要:
A process for producing peroxydicarbonates comprising first reacting at least one inorganic peroxide with at least one alkali metal hydroxide to form at least one alkali metal peroxide. The at least one alkali metal peroxide is added to a mixture of at least one haloformate, at least one dispersant and water. The mixture is homogenized during the entire reaction to form a peroxydicarbonate. The peroxydicarbonate is dispersed as small droplets of from 1 to 10 microns in size in the aqueous mixture. The entire mixture is added to a polymerization reactor containing an ethylenically unsaturated monomer. The peroxydicarbonate functions as the free radical initiator to polymerize the monomer. The peroxydicarbonate is substantially free of organic solvents and plasticizers. The resulting polymers are of high quality.
摘要:
A process for producing peroxydicarbonates comprising first reacting at least one inorganic peroxide with at least one alkali metal hydroxide to form at least one alkali metal peroxide. The at least one alkali metal peroxide is added to a mixture of at least one haloformate, at least one dispersant and water. The mixture is homogenized during the entire reaction to form a peroxydicarbonate. The peroxydicarbonate is dispersed as small droplets of from 1 to 10 microns in size in the aqueous mixture. The entire mixture is added to a polymerization reactor containing an ethylenically unsaturated monomer. The peroxydicarbonate functions as the free radical initiator to polymerize the monomer. The peroxydicarbonate is substantially free of organic solvents and plasticizers. The resulting polymers are of high quality.
摘要:
The present invention relates to an aqueous emulsion comprising a dispersant of a modified polyvinyl alcohol with an ethylene unit content of 2 to 9 mol % and a degree of hydrolysis of at least 95 mol %, a dispersoid of a polymer of an ethylenically unsaturated monomer, and a ratio (.eta.2 rpm/.eta.20 rpm) of Brookfield viscosity at 30.degree. C., 2 rpm (.eta.2 rpm) as against Brookfield viscosity at 30.degree. C., 20 rpm (.eta.20 rpm) being 1 to 1.8 when the latter viscosity (.eta.20 rpm) is adjusted to 5,000 to 10,000 mPa.multidot.S.The aqueous emulsion according to the present invention is excellent in structural viscosity (flowability, high speed application performance), provides coated layers with high water resistance and low-temperature stability, and can be suitably used extensively as an adhesive for paper, wood and plastics, as a binder for impregnated paper and non-woven products, as an additive for mortar, as a paint, and in paper and fiber processings.
摘要:
The invention provides inherently tacky, polymeric, organic, solvent-insoluble, solvent dispersible, elastomeric, pressure sensitive adhesive microspheres having pendant hydrophilic polymeric or oligomeric moieties having a degree of polymerization greater than or equal to 2. The microspheres which are sterically stabilized can offer enhanced stability against coagulation caused by alkali, alkali salts, polyelectrolytes and repeated freeze/thaw cycles. The present invention also provides pressure-sensitive adhesives comprising these microspheres including aerosol spray PSAs, coated sheet materials prepared therefrom, and method of making the microspheres.
摘要:
A process for producing monodispersed fine particles of a vinyl polymer is disclosed, which comprises polymerizing monomers containing at least one vinyl monomer selected from the group consisting of aromatic vinyl compounds, acrylic esters, and a methacrylic ester in the presence of (1) a surface active agent represented by formula (I) ##STR1## wherein R.sub.1 and R.sub.2, which may be the same or different, each represents a substituted or unsubstituted alkyl group having from 4 to 8 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted cyclohexyl group and M represents an alkali metal, (2) from 10.sup.-3 to 10.sup.-1 mol/l of a persulfate as a polymerization initiator, and (3) from 10.sup.-4 to 10.sup.-2 mol/l of a divalent metal sulfate as an electrolyte. Monodispersed vinyl polymer fine particles having a particle size of 1 .mu.m or greater with a very narrow size distribution are obtained.
摘要:
(1) Pyrrolidonyl acrylate block polymers having the formula ##STR1## wherein n has a value of 1 to 3; X and X' are dissimilar and each is hydrogen or methyl; y and z each have a value of from 1 to 40, except that at least one of y and z is greater than 1 and R is hydrogen or methyl;(2) preparation of said polymers and(3) uses of said polymers.
摘要:
A process for the preparation of aqueous polymer dispersions comprising polymerizing vinyl esters and up to 50% by weight of the total monomer of compounds with unsaturated ethylenic bonds at a temperature of 10.degree. to 100.degree. C. in the presence of an at least partially water-soluble free-radical initiator and at least one starch member of the group consisting of cyanalkylated starch, hydroxyalkylated starch and carboxyalkylated starch and optionally present conventional adjuvants with the starting mixture containing not more than one-third of the total monomers and the remaining monomers being added by metering during the polymerization, the initiators being at least one member of the group consisting of hydrogen peroxide and organic hydroperoxides in an amount of at least 30 mmol per kg of total monomer mixture and optionally present water-soluble reducing agent and the amount of starch being at least 1% by weight based on the total monomer weight.
摘要:
A dispersion of water soluble or water swellable polymer in water immiscible liquid is made by reverse phase polymerization utilizing a dispersing system comprising a polymerization stabilizer and the resulting dispersion, optionally after dehydration, may be distributed into water utilizing a distributing system. The dispersing system or the distributing system, or both, includes at least one non-ionic compound selected from C.sub.6-12 alkanols, C.sub.4-12 alkylene glycol monoethers and their C.sub.1-4 alkanoates, C.sub.6-12 polyalkylene glycol monoethers and their C.sub.1-4 alkanoates and benzyl alcohol. Novel dispersions are made by reverse phase polymerization and, in particular, include a non-ionic compound selected from C.sub.4-12 alkylene glycol monoethers, their C.sub.1-4 alkanoates and C.sub.6-12 polyalkylene glycol monoethers and their C.sub.1-4 alkanoates. When the polymer is water soluble a solution of it in water can be made by distributing the dispersion into water.