A gel coat, spraying and brushing
In order to improve and beautify the surface state of glass steel products, improve product value, and the inner glass steel from erosion, prolong the service life of products, we will generally work surface products into a layer with pigment paste (paste), high content of resin adhesive, it is also pure resin. Available surface mat reinforced. The adhesive layer is called gel coat (also known as the surface layer or decorative layer). Production quality of gel coat will directly affect the product quality and the external resistance, water resistance and chemical resistance of erosion, so in the gel coat spraying or brushing should pay attention to the following points:
(1) the configuration of gel coat resin, to fully mix, especially the use of pigment paste, if uneven mixing, will make the products appear on the surface of spots and stripes, which not only affects the appearance, but also reduce its physical properties. This should be possible by mechanical stirring and mixing, the best mixing machine does not produce a whirlpool, to avoid entering into the air.
(2) gel can brush or spray gun to spray. When spraying should be volatilization viscosity and added spraying process adding 5~7% styrene resin of styrene to adjust.
(3) coating layer thickness should be accurately controlled at 0.3~O.5mm, usually in the unit area are used to control the quality of gel, the gel dosage is 350~550g/ square meters, so that they can achieve the required thickness.
Gel coat thickness should be appropriate, not too thin, but not too thick, if the coat is too thin, may be curing incomplete, and gel on the back of the glass fiber easily exposed, affecting the appearance quality, not to beautify and protect glass steel products; if the coat is too thick, it is easy to crack. Not resistant to impact, especially not stand from the opposite direction to the impact of products. Coat brushing is not uniform in the demolding process is easy to cause the crack, this is because the surface curing speed, the internal stress due to the resin.
(4) gel should be applied evenly, avoid the local accumulation of coat.
(5) the curing degree of the gel coat must grasp.
The best way to check whether the gel coat curing moderate touch method that is used to make thousands of net finger touches the gel coat surface, if you feel a little sticky but not sticky, that gel coat has basically cured, then proceed to the next step of the paste operation, to ensure the glue layer and the back with the whole layer.
Two, determine the process route
The process route is related to product quality, product cost, production cycle (production efficiency) and so on. Therefore, the technical conditions (environment, temperature, medium, load) must be used before the production of the product...... And so on, the product structure, production quantity and construction conditions, such as a comprehensive understanding, through analysis and study, to determine the molding process plan, in general, should be considered in the following aspects:
(1) reasonable selection of raw and auxiliary materials, formula and paving method according to the requirements of products.
(2) according to the product geometry, production quantity, determine the structure of the mold and die material.
(3) according to the climate conditions and task priorities, determine the curing method.
Three, the main content of process design
(1) according to the technical requirements of the products, choose suitable materials (reinforced materials, structural materials and other auxiliary materials, etc.). In the choice of raw materials, the main considerations are as follows:
Whether the product meets the acid, the alkaline medium, the kind, the concentration, the use temperature, the contact time and so on.
Are there light transmittance, flame retardant and other performance requirements?.
In mechanical performance, is it dynamic or static load?.
Are there any leakage prevention and other special requirements?.
(2) determine the structure and material of the die.
(3) the selection of release agent,
(4) determination of resin curing and curing system.
(5) according to the requirements of the thickness and strength of the given product, the varieties, specifications, layers and paving methods of the reinforcing material are determined.
(6) establishment of molding process regulations.
Four. The paste system of glass fiber reinforced plastic
Paste is an important procedure of hand lay up process, must do fine operation quickly and accurately, the resin content uniformity, no bubble, no bad, does not damage the surface impregnated fiber and product level, to ensure the quality of products. Quality is good or bad, with the operator's proficiency and work attitude seriously or greatly, therefore, paste work is simple, but the product paste system is not too easy, should be taken seriously.
(1) thickness control
FRP thickness control, technical problems encountered are hand paste process design and production process, when we know that some products required when the thickness of the required calculation, to determine the content of filler and resin, the reinforced material specifications, the number of. Then calculate the approximate thickness according to the following formula.
T = (G1n1, ten, G2n2 +...) * (0. 3940. 909k1+0.4 * k1k2)
Type: - calculated thickness of GRP (mm);
Mass per unit area G1, G2 - all kinds of cloth or mat (kg/ m);
N1, N2 - layers of fabric or felt of various specifications;
0.394 - fiber thickness constant;
0.909 - thickness constant of polyester resin;
0.400 - the thickness constant of the packing;
K1 - ratio of resin content to glass fiber content;
K2 - filler content to