Search

KR-20260066626-A - SUPER ABSORBENT POLYMER AND PREPARATION METHOF THEREOF

KR20260066626AKR 20260066626 AKR20260066626 AKR 20260066626AKR-20260066626-A

Abstract

The present invention can provide an absorbent resin and a method for manufacturing the same, and an article comprising said absorbent resin, by using a combination of a specific chelating agent and a metal salt in a predetermined content range and controlling the specific physical properties of a base resin and a surface-crosslinked absorbent resin to a predetermined range, thereby simultaneously improving the absorption capacity, gel strength, and absorption rate corresponding to the trade-off relationship among the physical properties of the absorbent resin.

Inventors

  • 정지윤
  • 이세린
  • 양승훈

Assignees

  • 주식회사 엘지화학

Dates

Publication Date
20260512
Application Date
20251027
Priority Date
20241104

Claims (14)

  1. A polyacrylic acid (salt)-based absorbent resin comprising: a base resin; and a surface cross-linking layer formed on the surface of the base resin; and Absorbent resin satisfying the conditions of (i) to (iii) below: (i) The gel strength measured after swelling by absorbing 50 g of a 0.9 wt% sodium chloride and 0.005 wt% aqueous solution of ascorbic acid into 0.2 g of absorbent resin is 0.5 N or greater, and (ii) The absorption capacity (FSC) according to EDANA NWSP 240.0.R2 is 65.0 g/g or higher, and (iii) The absorption rate of physiological saline according to the vortex measurement method is 44 seconds or less.
  2. In paragraph 1, The above absorbent resin is, (i) The gel strength measured after swelling by absorbing 50 g of a 0.9 wt% sodium chloride and 0.005 wt% aqueous solution of ascorbic acid into 0.2 g of absorbent resin is 0.55 N or higher, and (i) The absorption capacity (FSC) according to EDANA NWSP 240.0.R2 is 66.5 g/g or higher, and (iii) Absorbent resin having an absorption rate of 43 seconds or less in physiological saline according to the vortex measurement method.
  3. In paragraph 1, The above absorbent resin is an absorbent resin that further satisfies at least one of the following conditions (iv) to (vi): (iv) The centrifugal retention capacity (CRC) measured according to EDANA NWSP 241.0.R2 is 37.5 g/g or greater, and (v) The pressurized absorption capacity (0.7 AUP) for 1 hour at 0.7 psi for physiological saline (0.9 wt% sodium chloride aqueous solution), measured according to the EDANA method NWSP 242.0.R2, is 8.0 g/g or greater, and (vi) Permeability is 500 seconds or less.
  4. In paragraph 1, The above absorbent resin is an absorbent resin comprising at least one of diethylenetriamine pentaacetic acid (DTPA), ions derived from aluminum sulfate, salts, and decomposition products thereof.
  5. In paragraph 1, The above absorbent resin is an absorbent resin that does not contain an amino acetate-based chelating agent other than diethylenetriamine pentaacetic acid.
  6. In paragraph 1, The above absorbent resin further comprises a silica layer formed on the surface cross-linked layer.
  7. An article comprising an absorbent resin as described in any one of paragraphs 1 through 6.
  8. In Paragraph 7, The above article is one or more selected from absorbent articles, sanitary products, soil repair agents, waterproofing materials for civil engineering and construction, seedling sheets, freshness preservatives, poultice materials, and electrical insulators.
  9. (i) a step of forming a hydrogel polymer by crosslinking an acrylic acid monomer having at least some of neutralized acidic groups in the presence of an internal crosslinking agent, a polymerization initiator, and diethylenetriamine pentaacetic acid (DTPA); (ii) a step of preparing a base resin powder comprising a cross-linked polymer obtained by drying and grinding the above-mentioned hydrogel polymer; and (iii) a step of preparing an absorbent resin having a surface crosslinking layer formed on the base resin by mixing the above base resin powder with a surface crosslinking composition containing aluminum sulfate and a surface crosslinking agent, and then heat-treating the mixture; wherein The above diethylenetriamine pentaacetic acid (DTPA) is included in an amount of 100 ppmw to 1,500 ppmw based on 100 parts by weight of the above acrylic acid monomer, and The above aluminum sulfate is included in an amount of 0.05 to 0.6 parts by weight based on 100 parts by weight of the base resin, and A method for manufacturing an absorbent resin, wherein the difference between the water retention capacity (CRC BR ) of the base resin prepared in step (ii) and the water retention capacity (CRC PD ) of the absorbent resin with a surface cross-linked layer formed in step (iv), as measured according to EDANA NWSP 241.0.R2, is controlled to be 15.0 g/g or less.
  10. In Paragraph 9, A method for manufacturing in which the difference between the water retention capacity (CRC BR ) of the base resin prepared in step (ii) and the water retention capacity (CRC PD ) of the absorbent resin with a surface cross-linked layer formed in step (iv), as measured according to EDANA NWSP 241.0.R2, is 13.0 g/g or less.
  11. In Paragraph 10, The centrifugal retention capacity (CRC) of the base resin measured according to EDANA NWSP 241.0.R2 is 45 to 55 g/g, and A method for manufacturing the above absorbent resin, wherein the centrifugal retention capacity (CRC) is 37.5 to 47 g/g.
  12. In Paragraph 11, A method for manufacturing in which the weight ratio of the above diethylenetriamine pentaacetic acid (DTPA) and the above aluminum sulfate is 1:3 to 1:50.
  13. In Paragraph 11, The above manufacturing method is, (iv) A manufacturing method further comprising the step of mixing an absorbent resin with a surface cross-linked layer with silica.
  14. In Paragraph 13, A manufacturing method in which the above silica is included in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the above absorbent resin.

Description

Super Absorbent Polymer and Preparation Method Thereof The present invention relates to an absorbent resin and a method for manufacturing the same, in which the absorbent capacity, gel strength, and absorption rate of which are in a trade-off relationship are simultaneously improved by using a combination of a specific chelating agent and a metal salt in a predetermined content range and controlling the specific physical properties of a base resin and a surface-crosslinked absorbent resin to a predetermined range, and an article comprising said absorbent resin. Super Absorbent Polymer (SAP) is a synthetic polymer material capable of absorbing 500 to 1,000 times its own weight in moisture, and developers name it by different names such as SAM (Super Absorbency Material) and AGM (Absorbent Gel Material). Such absorbent polymers began to be commercialized for sanitary devices, and are now widely used in various fields, including sanitary products such as children's disposable diapers, soil conditioners for horticulture, waterproofing materials for civil engineering and construction, seedling sheets, freshness preservation agents in the food distribution sector, materials for compresses, and electrical insulation. The above-mentioned absorbent resin is widely used in the field of hygiene products such as diapers and sanitary pads. For these applications, it is necessary to exhibit high absorption capacity for moisture and other substances, and the absorbed moisture must not leak out even under external pressure. In addition, it is necessary to maintain its shape well even when swollen after absorbing water, thereby exhibiting excellent permeability. In particular, as efforts continue in recent years to provide diapers that exhibit excellent performance while having a thinner thickness and lighter weight, much attention is being focused on providing absorbent resins with improved absorption speed and performance. Along with the aforementioned rapid absorption speed and performance, it is necessary to exhibit gel strength with high long-term stability. As a result, urine is not only uniformly and rapidly dispersed into the absorbent core of the diaper, but skin stability can also be enhanced over a long period. However, when attempting to increase gel strength using previously known methods, there was a disadvantage in that the basic absorption rate and absorption performance (under no pressure) of the absorbent resin itself were significantly reduced. For example, conventionally, chelating agents such as EDTA were applied to improve gel strength, but there were limitations in market entry due to insufficient absorption rate and capacity of the absorbent resin. Furthermore, there was a problem where gel strength decreased when attempting to improve absorption rate and capacity. Accordingly, there is a continuous demand for the development of absorbent resins in which absorption capacity, gel strength, and absorption rate are simultaneously improved, despite their trade-off relationship. The present invention will be described in detail below. All terms used in this specification (including technical and scientific terms) may be used in a meaning commonly understood by those skilled in the art to which the present invention pertains, unless otherwise defined. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise. Throughout this specification, when a part is described as "comprising" a certain component, it should be understood as an open-ended term implying the possibility of including additional components rather than excluding other components, unless specifically stated otherwise. Additionally, as used herein, "preferred" and "preferably" refer to embodiments of the invention that may provide certain advantages under certain conditions. However, other embodiments may also be preferred under the same or different conditions. Furthermore, the mention of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention. Terms such as first, second, third, etc. are used to describe various components, and these terms are used solely for the purpose of distinguishing one component from another. The terms "polymer" or "polymer" as used in this specification refer to a state in which water-soluble ethylene-based unsaturated monomers are polymerized, and may encompass all moisture content ranges or particle size ranges. Among the polymers, a polymer having a moisture content (water content) of about 40 weight% or more in the state before drying after polymerization may be referred to as a hydrogel polymer, and particles obtained by grinding and drying such hydrogel polymers may be referred to as a cross-linked polymer. Furthermore, the terms "base resin" or "base resin powder" refer to a polymer formed by drying a