The resin solid acid is a sulfo group-modified resin obtained by introducing sulfo groups into a raw material resin in an uncarbonized state, the yield of the sulfo group-modified resin based on the weight of the uncarbonized raw material resin is 80% or more, the amount of sulfo groups in the sulfo group-modified resin is 1 mmol/g or more, and the raw material resin is in the form of a powder, granules or fibers. In addition, the method for producing the resin solid acid is a production method for obtaining a sulfo group-modified resin by comprising a step for adding a sulfonating agent in the form of any of sulfuric acid, fuming sulfuric acid or chlorosulfonic acid to a raw material resin in an uncarbonized state, and a step for heating the uncarbonized raw material resin at 200 C. or lower.

A method of forming a binder composition includes providing a urea-formaldehyde resin and combining one or more starch compounds with the urea-formaldehyde resin to form a starch modified urea-formaldehyde resin. The one or more starch compounds may be combined with the urea-formaldehyde resin so that the starch modified urea-formaldehyde resin includes about 1 wt. % to about 10 wt. % of the one or more starch compounds.

A method of forming a binder composition includes providing a urea-formaldehyde resin and combining one or more starch compounds with the urea-formaldehyde resin to form a starch modified urea-formaldehyde resin. The one or more starch compounds may be combined with the urea-formaldehyde resin so that the starch modified urea-formaldehyde resin includes about 1 wt. % to about 10 wt. % of the one or more starch compounds.

The present invention relates to a method for preparing a hollow covalent organic framework (COF) material and hollow COF material prepared by said method. Said method is characterized in including a monomer displacement step in the method, thereby obtaining the hollow COF material with a controllable particle size, wall thickness and/or specific surface area.

The present invention relates to a method for preparing a hollow covalent organic framework (COF) material and hollow COF material prepared by said method. Said method is characterized in including a monomer displacement step in the method, thereby obtaining the hollow COF material with a controllable particle size, wall thickness and/or specific surface area.