FRP having improved workability and method of manufacturing the same

Abstract

The present invention relates to a glass fiber reinforced plastic with improved workability and a method for manufacturing the same. The glass fiber reinforced plastic according to the present invention comprises a glass fiber layer; and a polyurethane layer coated on the glass fiber layer, wherein the glass fiber layer comprises a fabric layer located inside; and non-woven layers located on both sides of the fabric layer.

Description

Technology Field

[0001] The present invention relates to a glass fiber reinforced plastic with improved workability and a method for manufacturing the same. Background Technology

[0002] Glass fiber reinforced plastics are being used for purposes such as insulation. However, conventional glass fiber reinforced plastics have problems such as irritating odors and toxicity.

[0003] In addition, this leads to poor working conditions at the job site, resulting in low work efficiency. The problem to be solved

[0004] The objective of the present invention is to provide a glass fiber reinforced plastic with improved workability and a method for manufacturing the same. means of solving the problem

[0005] The objective of the present invention is achieved by a glass fiber reinforced plastic with improved workability comprising: a glass fiber layer; and a polyurethane layer coated on the glass fiber layer, wherein the glass fiber layer comprises: a fabric layer located inside; and non-woven layers located on both sides of the fabric layer.

[0006] The above polyurethane layer can be formed by curing a polyurethane prepolymer having an NCO content of 9 to 16% and a molecular weight of 9,000 to 25,000.

[0007] Another objective of the present invention is achieved by a method for manufacturing glass fiber reinforced plastic with improved workability, comprising the steps of: providing glass fibers comprising a fabric layer located inside and non-woven layers located on both sides of the fabric layer; providing a polyurethane prepolymer having an NCO content of 9 to 16% and a molecular weight of 9,000 to 25,000; coating the glass fibers with the polyurethane prepolymer to provide an FRP sheet; and applying a curing agent to the FRP sheet to cure it.

[0008] The above coating can be mechanically coated by using a roll to coat about 30 to 70% of the weight of the glass fiber after heating the polyurethane prepolymer to 40 to 80°C (viscosity 10,000 or 60,000 cps).

[0009] The above curing agent may include alcohol (40~70%), ethylene oxide (10~20%), tin-based catalyst (1~5%), and water (5~10%). Effects of the invention

[0010] According to the present invention, a glass fiber reinforced plastic with improved workability and a method for manufacturing the same are provided. Brief explanation of the drawing

[0011] FIGS. 1 to 7 are photographs of glass fiber reinforced plastics manufactured in experimental examples of the present invention, and FIGS. 8 and 9 illustrate a coating method according to the present invention, and Figures 10 and 11 are photographs showing the types of glass fiber fabrics used in the present invention. Specific details for implementing the invention

[0012] The glass fiber reinforced plastic according to the present invention comprises a glass fiber layer and a polyurethane layer.

[0013] The glass fiber layer includes a fabric layer located inside and non-woven layers located on both sides of the fabric layer. The polyurethane layer is formed by curing a polyurethane prepolymer having an NCO content of 9 to 16% and a molecular weight of 9,000 to 25,000.

[0014] The resin used in glass fiber reinforced plastic (FRP) is a polyurethane prepolymer, characterized by modifying the resin to suit glass fibers and curing it using a specific curing agent suitable for it.

[0015] A polyurethane prepolymer containing 5 to 20 percent of NCO groups by weight is heated to 40 to 80°C (viscosity 10,000 to 60,000 cps), and then a glass fiber fabric or non-woven fabric is mechanically coated or impregnated with resin at a weight of 30 to 70 percent using a roll to manufacture a sheet or tape for FRP molding.

[0016] The glass fiber is characterized by having a laminated structure in which fabric and non-woven fabric are mixed, using a cross mat for the fabric and a non-woven fabric on the outermost surface.

[0017] Strength can be increased by using fabric, and the surface can be made smooth by using non-woven fabric.

[0018] The curing method of the polyurethane prepolymer is a method of curing using a specific curing agent, and this curing agent may include alcohol (40~70%), ethylene oxide (10~20%), tin-based catalyst (1~5%), and water (5~10%).

[0019] In glass fibers, the structure of the fabric is based on cross-weaving, and 30 to 200 g can be used, while the non-woven fabric can be 40 to 100 g.

[0020] Polyurethane may be free of volatile organic solvents.

[0022] The method for manufacturing polyurethane is described.

[0023] A polyurethane prepolymer with NCO 9 to 16% and a molecular weight of 9,000 to 25,000 is synthesized by mixing a polyisocyanate compound with a polyol or polyester compound in an appropriate equivalent ratio and reacting for 5 to 10 minutes. In addition, this polyurethane prepolymer can be used by mixing it with thickeners, curing agents, fillers, etc., and has the physical properties shown in [Table 1] below, so it can be used for applications such as adhesives, urethane putty, etc.

[0024] item Physical properties Test method Tensile strength (room temperature) - Fabric (Cross-mat) 115 ~ 140(MPa) ASTM-D638 Tensile strength (low temperature) - fabric (Cross-mat) 180 ~ 210(MPa) ASTM-D638 Tensile strength (room temperature) - Non-woven + Woven (Cross-mat) 175 ~ 190(MPa) ASTM-D638 Tensile strength (low temperature) - Non-woven + Woven (Cross-mat) 215 ~ 250(MPa) ASTM-D638 Flame retardancy (Flame Retardant Test) Passed Class B2 DIN 4102 -1, Class B2 viscosity 10,000 ~ 60,000(cps) Brookfield Curing time 15~70 (minutes) Brookfield NCO 10 ~ 15(%) -

[0025] Explain the method for synthesizing a curing agent.

[0026] Conventional polyurethane prepolymers are cured with water, but foaming occurs when cured with water. In this invention, a curing agent that suppresses specific foaming was developed without using water as a curing agent, and a mixture of 30-60% alcohol, 10-20% ethylene oxide, a small amount of tin-based catalyst, and 1 p of water was synthesized for 30 minutes and dispersed and sprayed onto each layer of a completed glass fiber reinforced plastic (FRP) molding sheet or tape.

[0027] Figure 1 shows a glass fiber reinforced plastic (FRP) molding sheet attached to urethane foam using a curing agent containing a tin-based catalyst, Figure 2 shows a glass fiber reinforced plastic (FRP) molding sheet attached to urethane foam using a curing agent containing a DABCO catalyst, and Figure 3 shows a sheet cured with water using a DAMDEE catalyst without using a curing agent.

[0029] Experimental results showed that no foaming occurred when using a curing agent containing a tin catalyst, whereas foaming occurred when using curing agents containing other catalysts such as DMDEE or DABCO. Additionally, severe foaming occurred when cured with water.

[0031] This explains the production process for FRP molding seats or tapes.

[0032] Glass fiber fabric is mechanically impregnated into a synthesized polyurethane prepolymer using a roller, and then coated by adjusting the amount of resin to approximately 30 to 70%. When conventional FRP products are coated with a brush or gloved hands, the overall coating amount is uneven, and the surface becomes rough upon curing.

[0033] Figure 4 shows glass fiber reinforced plastic coated with a brush attached to urethane foam, and Figure 5 shows mechanically coated glass fiber reinforced plastic attached to urethane foam.

[0035] The present invention uses a non-woven fabric for the outer surface and a woven fabric (Cross-mat) for the inner surface. By using a non-woven fabric, the disadvantage that the outer surface of the cross-woven glass fiber is not smooth can be overcome, and foaming urethane resin can be prevented. It also overcomes the difficulties of gel coat application. The reason the fabric is cross-woven is that the difference in strength is more than 2 to 3 times greater than that of other glass fibers.

[0036] Fig. 6 is a product produced with non-woven fabric + fabric and subjected to gel coating, and Fig. 7 is a photo of a product produced with only fabric and subjected to gel coating without using non-woven fabric.

[0038] There are methods of mechanically coating polyurethane resin onto glass fibers such as the method shown in Fig. 8 and the method shown in Fig. 9.

[0039] FIG. 8 shows a method of coating glass fibers using resin applied to a coating roll, and FIG. 9 shows a method of impregnating glass fibers with resin and coating using a roll. Among glass fibers, the method of FIG. 8 can be used for fabrics, and the method of FIG. 9 can be used for non-woven fabrics.

[0041] There are two methods of weaving: one where the warp and weft threads cross sequentially as shown in Fig. 10, and another where the warp threads move in a chain-like manner as shown in Fig. 11, and the weft threads bind 3 to 5 strands of warp threads together.

[0042] The characteristics of the fabric include a strength that is about 30-40% higher than [Photo 9] when hardened, making it useful for working on flat surfaces, and the [Photo 9] fabric has good formability, making it suitable for use on curved parts.

[0044] The present invention described above is not limited by the aforementioned embodiments and attached drawings, and it will be obvious to those skilled in the art that various substitutions, modifications, and changes are possible within the scope of the technical concept of the present invention.

Claims

Claim 1 delete Claim 2 delete Claim 3 A method for manufacturing glass fiber reinforced plastic with improved workability, comprising the steps of: providing a glass fiber layer, wherein the glass fiber layer comprises a fabric layer and a non-woven layer, and the non-woven layer is located on both sides of the fabric layer; providing an FRP sheet by coating a polyurethane prepolymer onto the glass fiber layer; and applying a curing agent to the FRP sheet to cure it, wherein in the coating, the polyurethane prepolymer is heated to 40 to 80°C and then 30 to 70% by weight of the glass fiber layer is mechanically coated using a roll, and the curing agent comprises alcohol, ethylene oxide, a tin-based catalyst, and water. Claim 4 delete Claim 5 delete

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