A simple method for preparing polyurethane composite fiberglass by vacuum infusion process

Abstract

The present invention belongs to the technical field of composite fiberglass manufacturing, and discloses a simple method for preparing polyurethane composite fiberglass using a vacuum infusion process, comprising the following steps: using vacuum adhesive tape to enclose an area on a heating platform and applying a release agent in the area. The present invention maintains airtightness inside the area by utilizing the close fit between the vacuum adhesive and the vacuum bag, laying four layers of fiber reinforcement material in the center of the release cloth, laying another layer of release cloth on top of the top fiber material, and laying a layer of guide net on each of the two ends covered by it, arranging a layer of spirally cut polyethylene tube on each guide net and connecting the PVC tube to the area extending outside the vacuum adhesive tape, and vacuuming the outside inward to draw in polyurethane using negative pressure, effectively verifying that polyurethane can be stably injected on the basis of a closed environment, preventing air leakage and resin blockage and stagnation, resin accumulation and bulging, and other undesirable phenomena.

Description

Technical Field

[0001] The invention belongs to the technical field of composite glass fiber reinforced plastic manufacturing, and in particular relates to a simple method for preparing polyurethane composite glass fiber reinforced plastic by using a vacuum infusion process. Background Art

[0002] The vacuum infusion process uses vacuum to infuse resin. The negative pressure of air is used to infuse the resin compound through distributed flow tubes, and atmospheric pressure is used to compact the product's structural layers. The vacuum infusion molding process involves placing the fiber-reinforced material directly onto the mold according to the structural design requirements. A layer of release cloth, typically a thin, low-porosity, low-permeability fabric, is placed over the fiber-reinforced material. A flow guide mesh is then placed over the release cloth, and then vacuum bagged and sealed.

[0003] The mold is sealed with vacuum bagging film, and vacuum pumps are used to evacuate the mold to a negative pressure. The release cloth is a low-porosity, easily removable fiber fabric, and the flow guide mesh is a high-permeability medium, with flow pipes located above the mesh. Resin enters the system through the inlet hose, where the flow guide pipes guide the main flow direction of the resin. The flow guide fabric distributes the resin to every corner of the laminate. After curing, the release cloth is peeled off, resulting in a highly dense, low-resin laminate. Compared to traditional processes, the vacuum infusion process significantly improves product strength and stiffness, as well as resin utilization. The resin dosage can be precisely controlled, resulting in a product with fewer bubbles and lower porosity.

[0004] However, the vacuum infusion process also has many disadvantages, such as air leakage during the injection process, resin blockage and stagnation, resin accumulation and bulging, etc. However, these disadvantages can be minimized or avoided by adjusting the process details and the actual operation of the personnel. However, in the initial verification and testing stage of the material, it is only necessary to produce a composite material with only a few layers of fiber, especially polyurethane materials that have high requirements for the environment and process. At this time, a simple vacuum infusion method is needed. Summary of the Invention

[0005] The object of the present invention is to provide a simple method for preparing polyurethane composite fiberglass by vacuum infusion process, so as to solve the problems raised in the above background technology.

[0006] In order to achieve the above object, the present invention provides the following technical solution: a simple method for preparing polyurethane composite fiberglass by vacuum infusion process, comprising the following steps:

[0007] S1: Use vacuum adhesive tape to enclose an area on the heating platform and apply release agent to the area. Then lay a layer of release cloth. Place four layers of fiber-reinforced material in the center of the release cloth. Lay another layer of release cloth on top of the top fiber-reinforced material and place a layer of guide net on each end of the covered material. Place a layer of spiral-cut polyethylene tube on each guide net and connect the PVC tube to the area outside the vacuum adhesive tape to ensure that the area between the vacuum bag and the vacuum adhesive tape is airtight.

[0008] S2: Seal the glue inlet, connect the vacuum port to the vacuum pump, control the heating table to heat, maintain the vacuum pressure at -0.1Mpa, cover the surface with a layer of insulation quilt, and continue running for two hours;

[0009] S3: Adjust the temperature of the heating table to 30°C, insert the glue inlet into the degassed polyurethane, open the glue inlet until the glass fiber is completely soaked, and close the glue inlet and vacuum pump;

[0010] S4: After the injection is completed, it is heated and cured, and the polyurethane fiberglass is obtained after demoulding.

[0011] Preferably, the heating platform is an electrically heated tempered glass platform.

[0012] Preferably, the release cloth is a polyester release cloth.

[0013] Preferably, the fiber reinforcement material is uniaxial polyurethane-specific glass fiber.

[0014] Preferably, the width of the first layer of fiber-reinforced material is 2 cm larger than the width of the second, third and fourth layers of fiber-reinforced material, the fiber direction of the first layer of fiber-reinforced material is the same as that of the third layer of fiber-reinforced material, the fiber direction of the second layer of fiber-reinforced material is the same as that of the fourth layer of fiber-reinforced material, the directions of the first layer of fiber-reinforced material and the third layer of fiber-reinforced material are at a 90-degree angle to the directions of the second layer of fiber-reinforced material and the fourth layer of fiber-reinforced material, and the three sides of the four layers of fiber-reinforced material are aligned.

[0015] Preferably, the guide net is overlapped on the protruding surface of the first layer of fiber reinforced material, and another piece of the guide net is overlapped on the fourth layer of fiber reinforced material on the opposite side.

[0016] Preferably, during the vacuuming in S2, the temperature of the heating stage is controlled at 50-100°C.

[0017] Preferably, during the vacuuming in S2, the temperature of the heating stage is preferably 70°C.

[0018] Preferably, the viscosity of the polyurethane after degassing in S3 is below 40 cp.

[0019] The beneficial effects of the present invention are as follows:

[0020] The present invention uses vacuum self-adhesive tape to enclose an area on a heating platform, and uses the close fit between the vacuum self-adhesive tape and the vacuum bag to keep the interior of the area airtight. Four layers of fiber-reinforced material are laid in the center of the release cloth in sequence, and another layer of release cloth is laid on the top of the top fiber material and a layer of guide net is laid on each of the two ends covered by it. A layer of spirally cut polyethylene tube is arranged on each guide net and connected to the area outside the vacuum self-adhesive tape by the PVC tube. Vacuum is drawn from the outside to the inside and polyurethane is drawn in using negative pressure. This effectively verifies that polyurethane can be stably injected on the basis of a closed environment, preventing air leakage, resin blockage and stagnation, resin accumulation and bulging, and other undesirable phenomena. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic cross-sectional view of the present invention.

[0022] In the figure: 1. Heating platform; 2. Release cloth; 3. Guide net; 4. Vacuum bag; 5. Fiber reinforcement material; 6. Glue injection hose; 7. Exhaust pipe; 8. Vacuum adhesive tape. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] like Figure 1 As shown, in an embodiment of the present invention, a simple method for preparing polyurethane composite fiberglass by vacuum infusion process is specifically performed by the following steps:

[0025] First, use vacuum adhesive tape 8 to enclose a 70cm*70cm area on the heating platform 1. Apply release agent in the area, then lay a 60cm*60cm release cloth 2, and lay a 44cm*42cm uniaxial glass fiber in the center of the release cloth 2. Then lay a 42cm*42cm uniaxial glass fiber. The fiber direction is at a 90-degree angle to the first piece. The three sides of these two uniaxial glass fibers are aligned, so that the first piece protrudes 2cm. The third piece is laid in the same way as the first piece, and the fourth piece is laid in the same way as the second piece. The four pieces of fiber are laid in the same way. Align the three sides of the uniaxial fiberglass, lay a 60cm*60cm release cloth 2 on the uniaxial fiberglass, overlap a 42cm*12cm guide net 3 on the protruding part of the first uniaxial fiberglass, and overlap a guide net 3 of the same size on the other end. Place a spirally cut guide tube on each guide net 3, and connect one end of the guide tube to a PVC tube extending to the area outside the vacuum adhesive tape 8. These two guide tubes serve as the glue injection tube 6 and the exhaust tube 7 respectively. Lay the vacuum bag 4 to cover the area of ​​the vacuum adhesive tape 8, tightly fitting the tape to prevent air leakage. Follow the steps below to perform vacuum dehumidification and glue filling.

[0026] Step 1: Seal the glue inlet of the glue injection tube 6, connect the vacuum port of the vacuum tube 7 to the vacuum pump, set the temperature of the heating platform 1 to 70 degrees Celsius, the vacuum pressure to -0.1Mpa, cover the surface with a layer of insulation quilt, and run continuously for two hours

[0027] Step 2: Set the temperature of the heating platform 1 to 30 degrees Celsius, insert the glue inlet into the completely degassed polyurethane, open the glue inlet until the glass fiber is completely soaked, close the glue inlet and vacuum port, and after the glue injection is completed, heat and cure to demold the polyurethane fiberglass.

[0028] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0029] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A simple method for preparing polyurethane composite fiberglass by vacuum infusion process, characterized by: The following steps are involved: S1: Use vacuum adhesive tape to enclose an area on the heating platform and apply release agent to the area. Then lay a layer of release cloth. Then, lay four layers of fiber reinforcement in the center of the release cloth. The fiber reinforcement material is uniaxial polyurethane special glass fiber, the width of the first layer of fiber reinforcement material is 2 cm larger than the width of the second, third and fourth layers of fiber reinforcement material, the fibers of the first and third layers of fiber reinforcement material have the same direction, the fibers of the second and fourth layers of fiber reinforcement material have the same direction, the directions of the first and third layers of fiber reinforcement material form a 90-degree angle with the directions of the second and fourth layers of fiber reinforcement material, and the three sides of the four layers of fiber reinforcement material are aligned; Place another layer of release cloth on top of the top fiber-reinforced material and a layer of guide net on each end of the covered material. Place a spiral-cut guide tube on each guide net and connect it to the area outside the vacuum adhesive tape with a PVC tube to keep the area between the vacuum bag and the vacuum adhesive tape airtight. S2: Seal the glue inlet, connect the vacuum port to the vacuum pump, control the heating table to heat, maintain the vacuum pressure at -0.1Mpa, cover the surface with a layer of insulation quilt, and continue running for two hours; S3: Adjust the temperature of the heating table to 30°C, insert the glue inlet into the degassed polyurethane, open the glue inlet until the glass fiber is completely soaked, and close the glue inlet and vacuum pump; S4: After the injection is completed, it is heated and cured, and the polyurethane fiberglass is obtained after demoulding.

2. The simple method for preparing polyurethane composite fiberglass by vacuum infusion process according to claim 1, characterized in that: The heating platform is preferably an electrically heated tempered glass platform.

3. The simple method for preparing polyurethane composite fiberglass by vacuum infusion process according to claim 1, characterized in that: The release cloth is preferably a polyester release cloth.

4. The simple method for preparing polyurethane composite fiberglass by vacuum infusion process according to claim 1, characterized in that: The guide net is overlapped on the protruding surface of the first layer of fiber reinforced material, and another piece of the guide net is overlapped on the fourth layer of fiber reinforced material on the opposite side.

5. The simple method for preparing polyurethane composite fiberglass by vacuum infusion process according to claim 1, characterized in that: During the vacuuming in S2, the temperature of the heating stage is controlled at 50-100°C.

6. The simple method for preparing polyurethane composite fiberglass by vacuum infusion process according to claim 5, characterized in that: During the vacuuming in S2, the temperature of the heating stage is preferably 70°C.

7. The simple method for preparing polyurethane composite fiberglass reinforced plastics by vacuum infusion process according to claim 1, characterized in that: The viscosity of the polyurethane after degassing in S3 is 40 cp or less.

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