Regardless of the production process used, when industry insiders talk about the performance of fiberglass, the vast majority of people only focus on the reinforcing materials, resins, and additives used, which is not a problem. However, in fact, everyone has overlooked an important factor, which is that the strength and modulus of fiberglass need to reach the most ideal state, and the most essential key is to determine the quality and durability of the interface adhesion between fiberglass and resin! This is the well-known "fiber, resin, and interface" that affect the basic performance and quality of fiberglass products. It can be said that whenever there are quality problems with fiberglass products, the reasons can be found in these three major factors. This is an iron rule that we need to keep in mind!
In the process of glass fiber drawing, a specialized surface treatment agent with a multiphase structure mainly composed of organic emulsion or solution needs to be coated on the surface of the glass fiber. These organic coatings are collectively referred to as fiberglass wetting agents. In composite materials, its role is to promote the bonding between glass fibers and the reinforced polymer.
Glass fiber wetting agent has a crucial impact on the interface of glass fiber reinforced composite materials. It lies between the surface of glass fiber and the surface of matrix resin, playing a role in the intermediate bonding layer and transmitting stress. When the content of glass fiber in composite materials reaches more than 15%, the strength of FRP mainly depends on the action of glass fiber.
The technical requirements for hand laid fiberglass products, except for some products that have different requirements according to their usage conditions, such as electrical performance as the main focus for electrical components, strength, non leakage, and appearance as the main focus for the hull, and anti-corrosion, strength, and non leakage as the main focus for chemical storage tanks, storage tanks, pipelines, and other products. However, regardless of the type of fiberglass products, the following technical requirements should be met:
(1) The resin content of the product should be basically uniform, and there should be no defects such as poor resin impregnation or excessive local resin that may affect the performance of the product. Regardless of whether the product has a gel coating layer or not, its surface should be flat and smooth, with uniform color, and there should be no defects such as cracks, layering, exposure, resin peeling, poor curing, wrinkling of the gel coating layer, and contamination from foreign inclusions.
(2) The product must not have obvious bubbles. If there is any, it needs to be repaired, and all defects (parts) after repair processing must not have too obvious traces. (There are many factors that can cause bubbles, such as improper use of brushes, high moisture content of curing agents, moisture on glass fibers, lack of thin layers for multiple applications of adhesive, and rapid resin curing.)
(3) In general, the adhesive content of products should be controlled at around 50%. In actual operation, this tests the patience of workers. Many hand laid fiberglass factories cannot meet this requirement. Practice has shown that within a certain range, strength increases with the increase of reinforcing material content. The higher the fiberglass content, the better, while the lower the resin content, the better! Products used for chemical corrosion prevention and leakage prevention should have a resin rich layer with a glue content controlled within the range of 70% to 85%.
(4) The product thickness should be basically uniform, and the shape and size should meet the requirements of the drawing.
(5) The product should be fully cured before leaving the factory, and its solidification degree should not be less than 90%. To determine the degree of curing of fiberglass, in addition to strength, the Bakol hardness value can also be measured. Most fiberglass products can achieve a hardness of 45-50 or above.
(6) The performance of the product must meet the design and usage requirements. There are different design requirements and material combinations for fiberglass products with different performance requirements.
For hand laid fiberglass products produced in bulk, in addition to 100% visual inspection of appearance, regular sampling or laboratory testing should be carried out according to different performance requirements of the products. If necessary, relevant testing departments should be sent for testing, and the inspection results should be recorded in detail. For existing defects, the causes should be analyzed, corresponding improvement measures should be formulated, and eliminated as soon as possible to ensure the continuous improvement of product quality. Overall, product quality needs to be guaranteed, mainly relying on the stability and reliability of raw materials and the correctness of operation! So choosing high-quality material suppliers and training qualified workers is particularly important!
Post time: May-06-2024
