Resin matrix

Pultrusion molding of fiberglass mainly uses unsaturated polyester resin and vinyl ester resin, while other resins also use phenolic resin, epoxy resin, methacrylic acid and other resins. In recent years, due to its advantages such as fire resistance, phenolic resins suitable for extrusion molding of fiberglass have been developed abroad, known as second-generation phenolic resins, which have been widely used. In addition to thermosetting resins, thermoplastic resins can also be selected as needed.

Fiber reinforced materials

The fiber reinforcement materials used in the extrusion molding of fiberglass are mainly E glass fiber untwisted coarse yarn. According to the needs of the product, C glass fiber, S glass fiber, T glass fiber, AR glass fiber, etc. can also be selected. In addition, synthetic fibers such as carbon fiber, aramid fiber, polyester fiber, and vinylon can also be selected for special purpose products. In order to improve the transverse strength of hollow products, continuous fiber felt, cloth, tape, etc. can also be used as reinforcing materials.

Auxiliary materials

(1) Initiator

The characteristics of initiators are usually represented by the content of reactive oxygen species, critical temperature, and half-life.

The commonly used initiators currently include:

MEKP (Methyl Ethyl Peroxide)

TBPB (tert butyl benzoate peroxide)

BPO (Benzoyl Peroxide)

Lm-P (special curing agent for extrusion)

TBPO (tert butyl peroxide)

BPPD (Diphenoxyethyl Peroxydicarbonate)

P-16 [Bis (4-tert butylcyclohexyl) peroxydicarbonate]

In practical applications, single component is rarely used, and usually two or three components are used in combination at different critical temperatures.

(2) Epoxy resin curing agent

Commonly used curing agents include anhydride, tertiary amine, and imidazole.

(3) Colorants

The colorants used in extrusion generally appear in the form of pigment paste.

(4) Filler

Fillers can reduce the shrinkage rate of products, improve their dimensional stability, surface smoothness, smoothness, and smoothness, as well as their smoothness or matte properties; Effectively regulate resin viscosity; It can meet different performance requirements, improve wear resistance, conductivity and thermal conductivity, etc. Most fillers can improve the impact strength and compressive strength of materials, but cannot increase the tensile strength; Can improve the coloring effect of pigments; Some fillers have excellent photostability and chemical corrosion resistance; Can reduce costs. It is best to have a gradient in the particle size of the filler to achieve the best usage effect. Now there are also surface treatments for fillers to increase their usage.

(5) Release agent

Release agents have extremely low surface free energy and can uniformly wet the surface of the mold, achieving a demolding effect. Excellent demolding effect is the main condition to ensure the smooth progress of the extrusion molding process.

The early extrusion molding process used external release agents, such as silicone oil. However, due to the large amount used and the unsatisfactory surface quality of the product, internal release agents have now been used.

Internal release agent is directly added to the resin, and under certain processing temperature conditions, it diffuses from the resin matrix to the surface of the cured product, forming a layer of isolation film between the mold and the product, playing a demolding role.

Internal release agents generally include phosphate esters, ovophosphate, stearates, triethanolamine oil, etc