An absorbent core, for use in an absorbent article, including a core wrap enclosing an absorbent material and including superabsorbent polymer particles. The core wrap includes a top side and a bottom side, and the absorbent core includes one or more area(s) substantially free of absorbent material through which the top side of the core wrap is attached to the bottom side of the core wrap, so that when the absorbent material swells the core wrap forms one or more channel(s) along the area(s) substantially free of absorbent material. The superabsorbent polymer particles have a time to reach an uptake of 20 g/g (T20) of less than 240 s as measured according to the K(t) test method.

A water-absorbent resin (21) has a shape in which a plurality of particles (40) having a substantially spherical shape is connected in a chain shape.

A preparation method of a three-layer self-healing flexible strain sensor includes steps of: preparing an encapsulating layer composite, so as to obtain a concentrated solution; preparing a strain sensitive layer composite, so as to obtain a thick liquid; dropping the thick liquid on a glass substrate, and statically curing at a room temperature; dropping the concentrated solution on a cured film obtained in the S3, and statically curing at the room temperature; striping a cured filmed obtained in the S4 from the glass substrate, and drawing out two wires as electrodes; and dropping the concentrated solution on the other surface of the cured film obtained in the S3 with a same amount of S4, and statically curing at the room temperature for obtaining the three-layer self-healing flexible strain sensor. The three-layer self-healing structure strain sensor can be prepared without using a repair agent, but can achieve rapid self-repair.

A preparation method of a three-layer self-healing flexible strain sensor includes steps of: preparing an encapsulating layer composite, so as to obtain a concentrated solution; preparing a strain sensitive layer composite, so as to obtain a thick liquid; dropping the thick liquid on a glass substrate, and statically curing at a room temperature; dropping the concentrated solution on a cured film obtained in the S3, and statically curing at the room temperature; striping a cured filmed obtained in the S4 from the glass substrate, and drawing out two wires as electrodes; and dropping the concentrated solution on the other surface of the cured film obtained in the S3 with a same amount of S4, and statically curing at the room temperature for obtaining the three-layer self-healing flexible strain sensor. The three-layer self-healing structure strain sensor can be prepared without using a repair agent, but can achieve rapid self-repair.

A preparation method of a powdery polycarboxylate superplasticizer is provided, including: mixing a superplasticizer monomer with water to produce a mixture, heating and melting the mixture to produce a melt system; carrying out a bulk polymerization reaction by adding an initiator, a chain transfer agent and an unsaturated carboxylic acid into the melt system, forming a polycarboxylate superplasticizer precursor; and neutralizing and pulverizing the polycarboxylate superplasticizer precursor to produce a powdery polycarboxylate superplasticizer. Water is added in the bulk polymerization and reacts with the superplasticizer monomer and the unsaturated carboxylic acid. While the bulk polymerization reaction is guaranteed to be efficiently carried out and the solid polycarboxylate superplasticizer is formed, the viscosity of a bulk polymerization reaction system is reduced. The superplasticizer is suitable for dry-mixed mortar, high-efficiency concrete and other products.

A process for producing superabsorbent particles by polymerizing a monomer solution or suspension, comprising drying of the resultant aqueous polymer gel in an air circulation belt drier, grinding, classifying, and optionally thermal surface postcrosslinking, wherein the aqueous polymer gel is introduced into the air circulation belt drier by means of an oscillating conveyor belt, the underside of the revolving conveyor belt is freed of adhering polymer gel by means of at least one stripper device, and the underside of the revolving conveyor belt is sprayed with water.

Methods for upcycling crosslinked sodium polyacrylate to pressure sensitive adhesives via (a) mechanochemical chain-shortening and esterification or (b) esterifying with high conversion with a Fischer esterification process are disclosed. Also disclosed is a pressure sensitive adhesive prepared by the disclosed methods and articles comprising the pressure sensitive adhesive, including, but not limited to, pressure sensitive tape, a bandage, a label, note pads, a decal, a stamp, an envelope, a sticker, packaging, automobile trim, and a film.

Provided is a method for preparing superabsorbent polymer, which includes conducting first surface crosslinking of a base resin powder while raising the temperature to a first temperature, in the presence of a first surface crosslinking agent; conducting second surface crosslinking of the first surface crosslinked base resin powder at a second temperature. According to the method of the present technology, surface crosslinking strength of the resulting superabsorbent polymer is increased, thus enabling preparation of superabsorbent polymer having little or no decline in absorbency under load even after anti-caking agent treatment.

A method for preparing a super absorbent polymer and a superabsorbent polymer prepared from the same are disclosed herein. In some embodiments, a method includes mixing super absorbent polymer particles, water and an additive form a hydrated super absorbent polymer, wherein the super absorbent polymer particles comprise a base polymer powder including a cross-linked polymer polymerized from a water-soluble ethylenically unsaturated monomer having an acidic group of which at least a part is neutralized, and a surface cross-linked layer formed on the base polymer powder, wherein the surface cross-linked layer is formed by further cross-linking the cross-linked polymer, and wherein the additive including a polyoxyalkylene aliphatic hydrocarbon ether carboxylic acid. The method can appropriately control the water content of the super absorbent polymer by water-addition or the like to suppress crushing or the like during transfer, and also can suppress deterioration of physical properties.

A method for preparing a superabsorbent polymer, and more particularly, a method for preparing a superabsorbent polymer in which it is possible to stably operate a process for preparing a fine powder reassembly while maintaining assembly strength of the fine powder reassembly, wherein a refined ratio is reducible, and an initial absorption speed of the superabsorbent polymer is improved, by adjusting a stirring speed and divisionally adding water to a fine powder in a process for the preparation of the fine powder reassembly, is provided.