Pultruded Epoxy Products Applications

Unsaturated polyester resin is the most common resin which is used in fiberglass pultruded products, and then epoxy resin. It is mainly used for products with high requirements on mechanical properties and heat resistance. Besides those two types of resin, vinyl ester resin, phenolic resin and  thermal plastic resin are also used during production. The resin requirements in pultrusion technology is: low viscosity, easy to saturate the reinforced material;  fast curing to adapt to the requirements of continuous forming production; good adhesion, curing shrinkage rate. Flexibility is good, the product is not easy to have cracks. Epoxy resin pultruded profiles are important type of glass fiber reinforced plastic material, and they have excellent strength properties.

Applications of fiberglass pultruded epoxy resin products:

1). Electrical engineering is the most widely used area currently, and it is very important development. Such as the transformer air catheter positioning rod, high voltage insulator core, high-voltage cable protection tube, cable rack, insulative ladder, insulating rod, pole, rail guard board, cable distributing frame, motor spare parts etc.

2). chemical anti-corrosion field is the fastest developing field in recent years. Typical products such as supporting structure of pipe network, pumping rod, downhole pressure pipeline, wastewater treatment equipment,, baffle of chemical industry, petroleum, chemical industry, papermaking, metallurgy and other factories in the railings, stair and platform railing, the grid floor.

3). Building construction, the structure is mainly used in the light structure, the upper structure of the high-rise structure or special purpose structure. Such as the activity of the housing structure, doors and windows structure with profile, truss, light bridge, railing, tent, suspended ceiling, structure, etc.

4). Sports and entertainment areas such as fiberglass fishing rod, hockey stick, ski pole, pole vault, bow etc.

5). Transportation areas such as automotive shelves, truck frame, refrigerated car, car spring board, luggage rack, insurance, deck, electric train track board, etc.

6). The energy field is mainly used in the solar collector, the wind turbine blade, the oil well and so on.

7). Aerospace applications such as aircraft and spacecraft antenna insulating tube, the spacecraft motor parts, fiberglass I beam, trough shaped beam and square beam, fiberglass rods, etc.

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Types Of FRP Tubes

There are many types of fiberglass tubes, today we'll introduce three types of tubes from aspects of production process, cross sections and raw materials.

1. According to the production process, frp tubes can be divided into pultruded tubes, pulwinding tubes, filament winding tubes, roller, etc. Filament winding pipe is widely used in the pipeline, and it has the advantages of high transverse strength, longitudinal strength, the disadvantage is it can't be produced continuously. For pultruded tubes, we can add the enhancement layer to increase the transverse strength, and the surface finish is very smooth, they can be produced continuously , and products can be customized according to customer's demand, the production efficiency is very high high, the disadvantage is that too large product is difficult to achieve, and it has high requirements of the machine and process. And fiberglass tubes with small and medium size have wide application.

2. According to the cross section shapes, fiberglass tubes can be divided into round tubes, square tubes, fiberglass rectangular tubes, etc, and our factory is able to manufacture different tubes at customer's request. 

3. According to the raw materials, now the most common resin is polyester resin tubes, there are vinyl ester resin, epoxy, phenolic, and other fiberglass tubes, different raw materials will produce tubes with different physical, mechanical and chemical properties. And according to the specific use of the environment, we are able to do customized production and processing of glass fiber tube to meet customer requirements.

As the fiberglass products have more and more applications in our life, we can see more fiberglass products in daily life. FRP tube as a very important branch of fiberglass products, it gets more recognition in different industries because of its various performance characteristics.

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Mechanical Properties Of Glass Fiber

Properties of glass fiber reinforced plastic equipment, especially its physics, mechanical properties and glass fiber and its products performance and glass fiber and its products of performance, varieties, specifications have a direct relationship. In chemical corrosion resistance, because the glass fiber is superior to synthetic resin, so in addition to the individual case, mainly depends on the corrosion resistance of the resin.

Mechanical properties: glass fiber is characterized by high tensile strength and specific strength.

It is generally believed that the tensile strength of glass fiber is related to the diameter and the length of the sample. Usually it is natural or chemical fiber high 5~30 times, 2 times higher than that of steel.

The proportion of glass fiber is small, is 2.5~2.7, is bigger than the natural or chemical fiber, is about the steel 1/3.

Glass fiber is an excellent elastic material, the stress and strain diagram is a straight line. The maximum elongation at break is related to the diameter of the fiber, but generally not more than 5%.

The modulus of elasticity is equal to that of pure Al. Only the 1/3~1/6 of the steel, which can be described as the biggest weakness of the glass fiber.

Glass fiber is more brittle and durable.

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Pultrusion Resin For Fiberglass Windows And Doors

Fiberglass pultruded window and door profiles are not the same as many general FRP products, they have multi-cavity and very thin wall thickness. Today we'll talk about the basic requirements of the pultrusion resin for the multi-cavity and thin-walled profile in high speed production:

(1) high reactivity;

(2) high glass temperature;

(3) the speed of saturation should be as high as possible;

(4) the proper viscosity characteristic.

Low reactive resin has slow speed reaction, even in the pultrusion mold for very short residence time and is unable to complete curing reaction, cementitious area will be too long, production difficulties: to regulate the reaction activity of the matrix resin, selection of appropriate initiator or choose a variety of initiator trigger.

Isophthalic resin glass transition temperature is high, the gelation time is short and the gel strength is higher, easily impregnated fiber and moderate viscosity (500 ~ 600 centipoises), packing is not easy to sink, very suitable for production of multi cavity thin wall material with special shape.

In order to improve the pultrusion speed and shorten the time of gelation, we should use the multi - level initiating system caused by low temperature, medium temperature and high temperature so that the resin matrix can be initiated at a lower temperature. In order to guarantee the inner and outer resin matrix can simultaneously cure, eliminate the crack and the profile bending phenomenon due to the curing time of the inside and outside resin matrix, adopt this system. It can also shorten the time of gelation. To improve the strength of the gel, and reduce the occurrence of the accident rate. The surface quality of the profiles can be improved by improving the tension speed and increasing the degree of curing.

                                                                                                     Source: www.unicomposite.com

Carbon Fiber Material Characteristics

There are two common types of carbon fiber products production process, pultrusion and roller. Carbon fiber materials and other strengthening materials comparision: (1) tensile strength: carbon fiber tensile strength is about 10 times than steel. (2) the tensile modulus of the carbon fiber composites is higher than that of the steel, but the tensile modulus of the aramid fiber and glass fiber composites is only half and 1/4 of the steel. (3): fatigue strength of carbon fiber pultruded and aramid fiber composite material fatigue strength is higher than that of a high strength. The fatigue limit of the metal materials is only 30% ~ 40% of the static load, under the action of alternating stress.. Due to the fiber and the matrix composite can ease the crack extension, and possibility of the existence of the internal force redistribution of fiber, composite fatigue limit is higher, about static load strength of 70% ~ 80%, and in front of the destruction of a significant signs of deformation. (4) weight: about 1/5 of the steel. (5) the comparison with carbon fiber board: carbon fiber sheet can be pasted on the structural surface of various shapes, and the plate is more suitable for the surface of a rule member. In addition, because of the adhesive strength of the adhesive layer, the amount of resin is more thick and the adhesive strength of the adhesive layer is better than that of the concrete interface.

                                                                                   Source: www.unicomposite.com

The Relationship Between Pultrusion And Molded Craft

In many different kinds of fiberglass products, it has the highest similarity between molding FRP grating and pultrusion product. It’s different from molded craft, while produce FRP grating by pultrusion technology. FRP pultrusion technology is a assembly by bars, but the molding craft is not. You get the only product ,while using the only mould.

The same features between mold craft and FRP pultrusin technology:

They are both the FRP production craft, also the product produced by those two ways can be combined. For example, when we install the operating platform, the key bars are FRP grating, but minor bars are pultrusion technology product, such as FRP  holder, FRP square tube and channel, bars and so on. In a word, the most similarity between them is supplement each other.

The differents features between molded craft and FRP pultrusin technology:

Relative to the similarity, the difference will be more.

1.The feature

pultrusion technology: fast production, easy operation, good variability(just change the mould, while produce the new production). As a result, the kind of pultrusion technology product is more than molding craft product.

Molded craft: the weakness is mainly aritificial operation, a waste of time, the mold can’t be changed, single product shape. But the advantage is stable property and durability.

2.Theory of production

Pultrusion technology product is produced by semi-automatic equipment, fast and easy operation, while the molding craft bars is made by aritificial operation, a waste of time and complex operation.

3. Usage

they have different range and occasion of usage. For example, FRP bridge is made of pultrusion technology bars, but fiberglass molded grating can’t achieve it.

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Pultrusion Process Parameter Control Element

Because the pultrusion process parameters to pull the thermosetting resin, by some complex factors which occurred in the mold of the constraints, and also by mutual influence between the other parameters, therefore in the pultrusion process, polymerization reaction of raw materials, and it is more difficult to accurately forecast.

At present, FRP pultrusion mould used in the monitoring and control of the sensing element has: temperature sensor, pressure sensor and the dielectric sensor three of the sesensors, must first solve the problem of wear resistant pultrusion. In addition, temperature,volume fraction of FRP mould, and the pulling speed, also will have a certain impact on the pultrusion molding process parameter sensor.

The current commonly used FRP pultrusion equipment, temperature sensing detection ofthe elements, often along the fiber direction, the surface area and placed in the forming mold, and the pressure sensing element, the middle position is often placed at the entrance of the pultrusion mould (usually pultrusion mould length 1000mm). The surface tension type pressure sensing element, often coated with chromium layer, in order to improve its performance of pultruded profiles wear resistance.

                                                                                                Source: www.unicomposite.com