853 results about "Residual monomer" patented technology

In order to produce inexpensively with high productivity a water-absorbent resin of which: the residual monomer content and the water-extractable content are both low, and the properties are high, and the colorability is low; there is provided a process for producing a water-absorbent resin, which is a process for producing a crosslinked water-absorbent resin by polymerizing a monomer component including acrylic acid and / or its salt in a major proportion wherein the acrylic acid is a product obtained by catalytic gas phase oxidation of propylene and / or propane, with the process being characterized by comprising the steps of: preparing the monomer component from an acrylic acid composition that includes the unneutralized acrylic acid and a methoxyphenol and has a methoxyphenol content of 10 to 160 ppm by weight (based on the unneutralized acrylic acid); and then carrying out radical and / or ultraviolet polymerization of the resultant monomer component.

In the production of an acrylate polymer by the steps of preparing a water-soluble unsaturated monomer having a ratio of neutralization in the range of 30 to 100 mol % and containing 50 to 100 mol % of an acrylate and then polymerizing the monomer, a method for the production of a hydrophilic resin which comprises using a water-soluble unsaturated monomer having a β-hydroxy propionic acid (salt) content of not more than 1,000 ppm. The hydrophilic resin obtained by this method exhibits excellent physical properties and has only a small residual monomer content. Further, a residual monomer content neither occurs nor increases in any using conditions.

An object of the present invention is to provide a water absorbing agent having a low amount of residual monomer, small variance of the amount of residual monomer among ranges of particle size distribution and favorable absorption properties, and being sanitary; an absorbing article; and a method for the production of a water absorbing agent. The water absorbing agent of the present invention has the amount of residual monomer of not higher than 500 ppm, and a residual monomer index of not greater than 0.30. The method for the production includes a first step of obtaining a hydrogel polymer by polymerizing an aqueous solution of a monomer including an unsaturated carboxylic acid and / or a salt thereof in the presence of a crosslinking agent; a second step of obtaining a water absorbent resin precursor which is in powder form and includes particles having a particle size of 300 to 850 μm and particles having a particle size of smaller than 300 μm as main components by drying said hydrogel polymer followed by pulverization and classification to adjust the particle size distribution, a third step of obtaining a water absorbent resin by heating a mixture of said water absorbent resin precursor and a surface crosslinking agent, which can form an ester bond around the surface of said water absorbent resin precursor, a fourth step of adding by spraying an aqueous solution that includes a sulfur-containing reducing agent to said water absorbent resin, and a fifth step of subjecting the mixture of the water absorbent resin and said aqueous solution to a heat treatment under an airflow of not lower than 40° C. but not higher than 120° C.

A tackifier resin is provided comprising monomer units from at least one aromatic monomer and at least one acrylate monomer; wherein the tackifier resin has a low residual monomer concentration. In other embodiments of the invention, the tackifier resin does not significantly decrease the moisture vapor transport rate of an adhesive composition comprising the tackifier resin, does not significantly increase fogging of an adhesive composition comprising the tackifier resin, and does not significantly exhibit skin sensitivity properties.A process to produce the tackifier resin is also provided. The process comprises contacting a tackifier resin product stream with at least one carrier at a temperature sufficient to remove a portion of at least one residual monomer from the tackifier resin product stream to produce the tackifier resin.