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How to evaluate the degree of cure of unsaturated polyester resin?

Jan 22, 2019

Evaluation of Curing Degree of Unsaturated Polyester Resin

In actual construction (unsaturated polyester resin), FRP products have different curing speeds due to different batches of different manufacturers. At the same time, they are affected by many factors such as ambient temperature and humidity during construction. Different. The following are some common methods for indirectly judging the degree of cure of FPR products.

1, on-site inspection
Touch the surface of the FRP product with no sticky feeling; use a clean cotton ball to draw acetone on the surface of the product to observe whether the cotton has color; knock the product to hear the sound, it should be crisp rather than fuzzy; use the coin to draw no scars.

2, Barcol hardness method
The Barcol hardness method is to test the hardness value of a molding material using a Barcol hardness tester. Generally, the paste hardness of 40 to 50, the degree of curing is achieved, and it can be put into use.

3, rebound method
The rebound method is to drop the small steel ball from a certain height to the surface of the cured resin to be tested. Due to the different degree of curing, the rigidity of the resin is different, so the rebound height is also different, and the rebound height can indicate the degree of curing.

4. Measuring the insoluble matter content in the molded product, that is, extracting the soluble component in the resin with acetone to obtain an insoluble matter content. This method is also applicable to epoxy or phenolic FRP, which is currently the most used method. The principle is that the resin is a linear molecule before solidification, is easily soluble in an organic solvent, and becomes a bulk network structure after solidification, and is insoluble in an organic solvent. The organic solvent is used to extract the soluble component in the cured resin. The degree of curing is indirectly explained by calculating the difference in weight between the FRP samples before and after the extraction.

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QuanZhou Neweco High Polymer Material Co.,Ltd.

Neweco is one of the leading unsaturated polyester resin manufacturers and  suppliers,widely used in automobiles, ships, rail transit, wind power  generation, pipe cans, heat and corrosion protection, building  materials, stone repair, sanitary ware, artificial stone and other  industries. Suitable for hand lay-up, spray, pultrusion, winding,  molding, vacuum introduction / RTM, casting and other molding processes. Neweco Resin is committed to excellence and focuses on the application  of composite materials to provide customers with comprehensive  solutions.

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