1. Preparation of Fiber Reinforced Materials:
Cloth or felt for hand paste molding should be pre-treated by surface treatment. Pre-treated fiber-reinforced materials should be selected as far as possible. No matter what kind of fibers and products, they must be kept dry and free from grease before use.
The cutting design of reinforcing materials is very important. Generally, the cutting should be concentrated in order to improve efficiency and save cloth. Attention should be paid to tailoring:
The longitudinal and latitudinal strength of cloth is different. It should be laid alternately vertically and horizontally according to the design requirements. For products with directional strength requirements, the one-way cloth can be used to enhance.
(2) For products with large surface fluctuations, the fiber cloth should be partially cut, but the cutting should be as little as possible, and the opening should be staggered.
(3) The lap length of reinforcing materials is generally 50mm. When the thickness is strictly required, the butt joint can be adopted, but attention should be paid to the wrong seam.
The size of cut glass cloth should be determined according to product size, performance requirements, and operation difficulty. There are many small pieces of joints with low strength. If construction is convenient, large pieces of cloth paste should be used as far as possible.
2. Preparation of resin glue:
The process parameters of resin adhesive include three indexes: viscosity, gel time and curing degree.
(1) Resin viscosity:
Resin viscosity, also known as fluidity, is an important index in hand paste forming. Excessive viscosity will make it difficult to coat, and it is not easy to immerse the reinforcing materials. Excessive viscosity will lead to the phenomenon of rubbing, which will affect the quality.
2. Gel time:
When the resin glue is prepared, the time to start heating, sticky and losing mobility is called gelation time. It is generally desirable to stop the gel for a period of time after completion of the paste. If the gel time is too short, the quality of the adhesive will be affected by the adhesive and impermeable fibers. On the contrary, long term mongrel can cause the loss of resin glue and the volatilization of crosslinking agents, resulting in incomplete solidification and lower strength.
The gelation time of the gel is shorter than that of the product. The gelation time of resin adhesive is related to formula, ambient temperature, humidity, product thickness and so on.
The gel time control of polyester gum is usually achieved by adjusting the amount of curing agent and accelerator.
(3) Curing degree:
Complete curing is an important condition to ensure product quality. From the point of view of technology, the degree of solidification is divided into molding strength and service strength. The former is to ensure that the product has demolding strength so that the product can be removed from the die without damage, while the latter requires the product to reach the use of strength.
In general, the curing degree in the production process is controlled by adjusting the formulation. For hand paste products, it is hoped that the stripping time can be controlled in 24 hours, which will affect production efficiency. When the room temperature is below 15 C, heating or heat preservation measures should be taken appropriately.
3. Preparation of glue paste:
Rubber coat paste is used to make surface coatings. Its function is to improve the weather resistance, water-resistance and chemical erosion resistance of products and prolong their service life.
Because of the thixotropy of the gel coat, it should be fully stirred when used. The thickness of the coating should be controlled between 0.25 and 0.4 millimeters. When the gel coat starts to gel, the glass fiber reinforced plastic is immediately pasted and released after being completely cured. When using the gel coat resin layer, there should be no pollution or infiltration of small bubbles between the gel coat and Fiberglass Statue.