The FRP pultruded profile process has the characteristics of a high degree of mechanicalization of the agricultural production system, continuous production, and stable product quality performance. The FRP pultruded profile has achieved sustained and stable rapid growth over the years. However, due to the small scale of most domestic pultruded plants and weak technical force, the FRP pultruded profile encountered many problems during the production process. The common problems are:

1. Thickening phenomenon of resin gel coat mixture
The so-called thickening phenomenon means that the viscosity of the prepared resin gel coat mixture gradually increases during use, and the increase speed of the viscosity gradually increases, until it reaches the level that the mixture is difficult or even impossible to use.
This phenomenon is often encountered by domestic FRP pultruded profile manufacturers, but it is difficult to find the problem and the solution. The reason for this phenomenon is that there are high acid components in the formula, which are mainly used in the formula. In-liquid release agent, this component chemically reacts with the basic fillers in the mixture such as calcium carbonate or metal oxide pigments to separate calcium ions or other metal ions. The FRP pultruded profile manufacturer tells you that these separated calcium ions or other metal ions will quickly chemically react with the carboxyl group at the end of the polyester molecular chain to form a complex to form a polyester-metal complex network Shape structure, so that the viscosity of the mixture increases sharply, the fluidity is reduced, and the rapid increase in viscosity makes it difficult to penetrate the glass fiber, so that the drawing resistance is also increased. The resulting product has performance degradation due to insufficient wetting. Highly acidic components will also chemically react with certain acid-sensitive pigments, causing the color of the product to drift.
2. The choice of filler
Filler is a very important component in the pultrusion formula. Proper use can improve the processability of the resin system and the performance of the cured product, and it can also significantly reduce the cost of composite materials. The manufacturer of FRP pultruded profile tells you that if it is used improperly, it will seriously affect the processing performance and product performance. Generally speaking, any powdered mineral can be used as a filler.
The effect of fillers on the liquid resin system is to increase viscosity, produce thixotropy, accelerate or retard curing, and reduce heat release. The FRP pultruded profile manufacturer tells you that among the process factors that it affects, the most important thing is the effect on viscosity and rheology. The main factor that affects viscosity is the oil absorption of the filler. When the oil absorption rate increases, the viscosity increases, or in other words, the lower the oil absorption rate under the condition of maintaining the same viscosity, the larger the amount of the filler can be added. In addition, the specific surface area of ​​the filler affects the polymerization rate. Light calcium carbonate, talc, etc. have a large specific surface area, which will retard solidification; while heavy calcium carbonate has a smaller specific surface area and has better curing performance.
The manufacturer of FRP pultruded profile tells you that by coating the surface of calcium carbonate with agricultural production systems to form active calcium carbonate, the aggregated particles are reduced, the dispersion degree is improved, and the inter-particle voids are reduced, thereby further reducing its oil absorption. In addition, the price of the filler is also an important reference for choosing which filler to use. Among the common fillers, the low cost is ground calcium carbonate and talc, the cost of surface activated ground calcium carbonate is slightly higher, the cost of kaolin is in the middle, and the higher is aluminum hydroxide. Aluminum hydroxide is usually used as a flame-retardant filler and not as an ordinary filler.
The FRP pultruded profile manufacturer tells you that various fillers have roughly the same effect on the mechanical and physical properties of the cured product. The effects on flame retardancy and electrical properties are slightly different. In addition, the impact on the dynamic mechanical properties of the product is more complicated, and is related to the particle size, particle size distribution, particle shape, hardness and filling amount of the filler.
3. Cracking of the product
Product cracking, including surface cracks and internal cracks, is a very uncomfortable problem for FRP pultruded profile manufacturers. The cause of cracks is mainly due to thermal stress caused by exothermic shrinkage. Many FRP pultruded profile manufacturers also have a consensus on this point. However, it is still difficult to find a better way to eliminate thermal stress in China. Although proper adjustment of mold temperature and pultrusion speed may temporarily alleviate this problem, with changes in environmental conditions and some uncertain reasons, cracks will reappear. Sometimes, under normal circumstances, cracks will suddenly appear, making you hard to prevent.
The FRP pultruded profile manufacturer tells you that you only need to add a small amount of anti-cracking brightening powder (2%-5% of the resin amount) to have a significant effect. Due to the small amount of addition, it has little effect on the performance of the product, and it can also enhance some properties. In addition to reducing cracking, it also has the advantages of increasing the gloss of the surface of the product and making the color of the product more uniform. Adding this component to the formula can reduce the scrap rate to a large extent and make the production more stable and smooth.