A method for preparing polyurethane profiles with localized reinforcement materials

Abstract

This invention discloses a method for preparing polyurethane profiles with localized reinforcement, comprising the following steps: S1, designing a one-time preforming fixture; S2, preparing the polyurethane profile; S3, cutting the cooled polyurethane profile according to requirements. This method for preparing polyurethane profiles with localized reinforcement significantly improves the cross-sectional performance of the polyurethane profile by adding reinforcement material to its circumferentially weak points during molding, thus enriching the application scenarios of the polyurethane profile. Furthermore, the molding position of the reinforcement material can be flexibly set according to the application requirements of the profile. Simultaneously, the reinforcement material is molded together with the fiber, resulting in high bonding strength and durability.

Description

Technical Field

[0001] This invention relates to the field of glass fiber reinforced composite materials technology, and specifically to a method for preparing polyurethane profiles with locally reinforced materials. Background Technology

[0002] Polyurethane profiles are a type of material with a constant cross-section, manufactured using thermosetting polyurethane combined with glass fiber through a pultrusion process. They possess superior axial tensile properties, as well as wear resistance, aging resistance, and high toughness. Polyurethane profiles also exhibit good thermal insulation properties, making them technically feasible for use in energy-efficient building doors and windows, transportation, and building materials, offering significant performance and cost advantages.

[0003] Polyurethane profiles made of ordinary pure glass fiber are produced through a continuous pultrusion process. Polyurethane profiles produced by pultrusion are made by bonding dispersed fiber bundles together with resin. Their axial properties are provided by the bonding force between the glass fiber, resin, and the fiber, resulting in excellent axial properties. However, their cross-sectional properties are mainly provided by the resin body and the bonding force between the resin and the fiber, so their cross-sectional properties are relatively weak, which limits the application scenarios of polyurethane profiles.

[0004] Solving these problems is now a top priority. Summary of the Invention

[0005] To address the technical problem of relatively weak cross-sectional performance of existing polyurethane profiles, this invention provides a method for preparing polyurethane profiles with locally reinforced materials.

[0006] The technical solution is as follows:

[0007] A method for preparing a polyurethane profile with localized reinforcement materials, comprising the following steps:

[0008] S1. Design a one-time preforming tooling, including the following steps:

[0009] S11. Calculate the cross-sectional area of ​​the polyurethane profile. Divide the cross-section of the polyurethane profile into multiple blocks according to the cross-sectional shape, and calculate the area of ​​each block.

[0010] S12. Calculate the number of fibers required to prepare the polyurethane profile and the number of fibers required for each block.

[0011] S13. Based on the shape and division of the polyurethane profile, map out the area of ​​the yarn threading hole of the pre-forming tooling. Combine the required number of fibers in each area to design the number, size and arrangement of the yarn threading holes so that the fibers are evenly distributed and fit the impregnation device and the inner wall of the mold.

[0012] S14. Set the length of the gap on the preforming fixture for the reinforcing material to pass through to be 5%-12% larger than the width of the reinforcing material;

[0013] S2. Prepare polyurethane profiles, including the following steps:

[0014] S21. Arrange the glass fibers neatly on the fiber yarn frame, and each bundle of fiber is pulled out from the yarn frame through an independent yarn hole;

[0015] S22. Use a tension meter to detect the tension of each fiber bundle, and adjust the fiber tension through a tension adjustment device to control the tension of each fiber bundle so that the tension of each fiber bundle is within the set range.

[0016] S23. Pass each bundle of fibers through the corresponding fiber hole on the pre-forming tooling.

[0017] S24. The reinforcing material is drawn out from the fixed frame, and after being initially constrained by the guiding device, it passes through the corresponding gap on the pre-forming tooling.

[0018] S25. At least the fibers are fed into the impregnation device to impregnate the resin, and the fibers and reinforcing materials are pre-formed by a secondary pre-forming fixture.

[0019] S26. The fiber and reinforcing material are introduced into the mold from the mold inlet;

[0020] S27. Use a heating plate to heat the mold, so that the resin reacts and cures rapidly after being heated, wrapping and bonding the fibers and reinforcing materials, and then pulling and molding it into a polyurethane profile through a traction device.

[0021] S3. Cut the cooled polyurethane profile according to requirements.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] A method for preparing polyurethane profiles with local reinforcement using the above technical solution can significantly improve the performance of polyurethane profiles in the cross-sectional direction by adding reinforcement materials at the weak points in the circumferential direction during the molding of the polyurethane profiles, thus enriching the application scenarios of polyurethane profiles. Furthermore, the molding position of the reinforcement materials can be flexibly set according to the application requirements of the profiles. At the same time, the reinforcement materials are molded together with the fibers, resulting in high bonding strength and durability. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a polyurethane profile production line;

[0025] Figure 2 A schematic diagram showing the addition of reinforcing material to a large portion of the outer surface of a polyurethane profile;

[0026] Figure 3 This is a schematic diagram showing the addition of reinforcing materials to the outer corners and inner parts of a polyurethane profile. Detailed Implementation

[0027] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0028] like Figure 1 As shown, a method for preparing a polyurethane profile with locally reinforced materials is carried out according to the following steps:

[0029] S1. Design a one-time preforming tooling, including the following steps:

[0030] S11. Calculate the cross-sectional area of ​​the polyurethane profile. Divide the cross-section of the polyurethane profile into multiple blocks according to the cross-sectional shape, and calculate the area of ​​each block.

[0031] S12. Based on the glass density and linear density of the selected fibers, the density of the resin, and the fiber mass fraction of the obtained polyurethane profile, calculate the number of fibers required to prepare the polyurethane profile and the number of fibers required for each block. In this embodiment, the fiber mass percentage in the polyurethane profile is 72%-85%, thereby ensuring excellent axial performance of the polyurethane profile.

[0032] Specifically, first calculate the volume V of the polyurethane profile:

[0033] V = S × L = V F + V R (1)

[0034] In equation (1), S is the cross-sectional area of ​​the polyurethane profile, L is the length of the polyurethane profile, and V is the cross-sectional area of ​​the polyurethane profile. F V is the volume of the fiber. R The volume of the fiber;

[0035] Calculate the fiber mass percentage ω m :

[0036]

[0037] In equation (2), m F For the mass of the fiber, m R For the quality of the resin;

[0038] Wherein, the mass m of the fiber F Represented as:

[0039] m F =ρ F ×V F (3)

[0040] In equation (3), ρ FThe glass density of the fiber;

[0041] The mass of the resin m R Represented as:

[0042] m R =ρ R ×V R (4)

[0043] In equation (4), ρ R This refers to the density of the resin after curing.

[0044] Fiber mass m F It can also be expressed by the linear density of the fiber (tex), the length (L) of the polyurethane profile, and the number of fibers (a):

[0045] tex×L×a=m F (5)

[0046] From equations (2), (3), and (4), we can obtain:

[0047]

[0048] From equations (3) and (5), we can obtain:

[0049]

[0050] From equations (1) and (6), we can obtain:

[0051]

[0052] From equations (7) and (8), we can obtain:

[0053]

[0054] Therefore, using formula (9), based on the glass density ρ of the selected fiber... F And linear density tex, density ρ after resin curing R And the fiber mass fraction ω of the polyurethane profile produced. m This allows us to calculate the number of fibers required to prepare the polyurethane profile and the number of fibers required for each block.

[0055] It should be noted that the amount of reinforcing material can be calculated based on the number of fibers removed, using the following formula:

[0056]

[0057] In equation (10), c is the number of fibers removed, FAW is the basis weight of the reinforcing material, and b is the width of the reinforcing material.

[0058] S13. Based on the shape and division of the polyurethane profile, map out the area of ​​the yarn threading hole of the pre-forming tooling. Combine the required number of fibers in each area to design the number, size and arrangement of the yarn threading holes so that the fibers are evenly distributed and fit the impregnation device and the inner wall of the mold.

[0059] S14. Set the length of the gap on the preforming fixture for the reinforcing material to pass through to be 5%-12% larger than the width of the reinforcing material. The smaller the gap width, the better the constraint effect on the reinforcing material. Make conformal design to guide the reinforcing material step by step into the expected shape.

[0060] S2. Prepare polyurethane profiles, including the following steps:

[0061] S21. The glass fibers are neatly arranged on the fiber yarn frame. Each bundle of fibers is pulled out from the yarn frame through an independent yarn hole, which can prevent the fibers from tangling and knotting.

[0062] S22. Use a tension meter to detect the tension of each fiber bundle, and adjust the fiber tension using a tension adjustment device to control the tension of each fiber bundle so that the tension of each fiber bundle is within the set range.

[0063] S23. Each fiber bundle passes through the corresponding fiber hole on the pre-forming tooling. In step S13, the position and size of the fiber hole are designed so that the fiber bundle can be limited and guided through the fiber hole.

[0064] S24. The reinforcing material is drawn out from the fixed frame, and after being initially constrained by the guiding device, it passes through the corresponding gap on the pre-forming fixture.

[0065] S25. At least the fibers are fed into the impregnation device to impregnate with resin, and the fibers and reinforcing materials are pre-formed using a secondary pre-forming fixture. The impregnation device is a semi-enclosed cavity in which the resin is stored. The material to be impregnated enters the cavity and is immersed in the resin to achieve the impregnation purpose.

[0066] Specifically, step S25 has the following two implementation methods:

[0067] Step S25, Implementation Method 1:

[0068] A secondary preforming fixture is placed at the inlet of the impregnation device. The fibers and reinforcing materials preformed by the secondary preforming fixture are fed into the impregnation device to impregnate with resin. The fibers and reinforcing materials exiting the impregnation device directly enter step S26. In this embodiment, both the fibers and reinforcing materials are fully impregnated with resin, thereby ensuring the bonding strength between the fibers and reinforcing materials and improving service life.

[0069] Step S25, Implementation Method Two:

[0070] In step S25, secondary preforming fixtures are installed at both the inlet and outlet of the impregnation device. Fibers preformed by the secondary preforming fixtures are fed into the impregnation device to impregnate with resin. Fibers exiting the impregnation device and reinforcing material not entering the impregnation device are preformed together by the secondary preforming fixtures and then proceed to step S26. In this embodiment, the reinforcing material is impregnated by excess resin on the fibers during the distance from the mold inlet to the curing zone. This method allows the reinforcing material to adhere more easily to the fiber surface, effectively reducing the risk of surface quality problems in the polyurethane profiles.

[0071] S26. The fiber and reinforcing material are introduced into the mold from the mold inlet.

[0072] S27. The mold is heated using a heating plate, causing the resin to react and cure rapidly, encapsulating and bonding the fibers and reinforcing materials. The resin is then pulled and molded into a polyurethane profile. In this embodiment, heating the mold to 80℃-210℃ ensures the quality of resin curing and guarantees the quality of the polyurethane profile.

[0073] S3. Cut the cooled polyurethane profiles according to requirements, usually using a cutting machine.

[0074] It should be noted that the reinforcing material is typically glass fiber mat or glass fiber fabric, but other materials are also possible. Examples of using glass fiber mat and glass fiber fabric as reinforcing materials are provided below:

[0075] Examples of using glass fiber mat as the reinforcing material:

[0076] Please see Figure 2 The reinforcing material is added to the upper and lower outer surfaces as shown in the diagram. The fiber mass fraction is controlled between 77% and 82%.

[0077] Sufficient glass fibers are placed on the yarn frame. Based on the cross-sectional area of ​​the product design and the information of the selected raw materials, the theoretical quantity of the required fibers and reinforcing materials is calculated using formulas (9) and (10). The fibers are then pulled out from the yarn frame and passed through the tension control device. The tension control device is adjusted so that the tension of each fiber bundle is within the range of 80N to 120N. The fiber bundles with uniform tension pass through the yarn guide plate for initial gathering, and then pass through the first pre-forming fixture to achieve the purpose of fiber bundling and reasonable arrangement. Then, they pass through the impregnation device, and after passing through the second pre-forming, they enter the mold until they reach the clamping position of the traction device. The traction force provided by the device achieves continuous traction.

[0078] Select two pieces of fiberglass mat, the size of which is determined according to the design dimensions of the profile and the location where the mat needs to be added. Place the selected fiberglass mat on the fixed frame, adjust its position to avoid interfering with the fibers, lead it out from the fixed frame, pass through the guide device and the first preforming fixture, the composite mat bypasses the impregnation device and passes through the second preforming fixture, and is then woven with the already threaded fibers (or sewn together with cotton thread), and led out of the mold together by the fibers.

[0079] Prepare a polyurethane resin, white component (polyol), black component (modified isocyanate), and additives. Mix them in a ratio of 112 parts white component, 100 parts black component, and 4 parts additives, and add them to the impregnation device to fully impregnate the fibers and glass fiber mat inside.

[0080] After being impregnated, the fibers and felt are heated and cured in a mold. The mold has three heating zones, with each zone measuring 230 mm from the mold outlet to the mold inlet. The mold heating and curing temperatures are set as follows: Zone 1: 80–100℃; Zone 2: 160–180℃; Zone 3: 180–200℃.

[0081] After the product is demolded and cooled, it is pulled by a traction device and then cut by a cutting machine according to different length requirements.

[0082] Examples of reinforcing materials using glass fiber fabric:

[0083] Please see Figure 3 The reinforcing material is added at the lower corner and the upper inner surface, as shown in the diagram. The fiber mass fraction is controlled between 79% and 85%.

[0084] A sufficient number of glass fibers are placed on the yarn frame. Based on the cross-sectional area of ​​the product design and the information of the selected raw materials, the theoretical number of fibers required is calculated using formulas (9) and (10). The fibers are then pulled out from the yarn frame and passed through the tension control device. The tension control device is adjusted so that the tension of each fiber bundle is within the range of 100N to 160N. The fiber bundles with uniform tension pass through the yarn guide plate for initial gathering, and then pass through the first pre-forming fixture to achieve fiber bundling and reasonable arrangement. After passing through the impregnation device and the mold, they reach the clamping position of the traction device, where the traction force is provided by the device to achieve continuous traction.

[0085] Select three pieces of fiberglass fabric, the size of which is determined according to the design dimensions of the profile and the location where the fiberglass fabric needs to be added. Place the selected fiberglass fabric on the fixed frame, adjust its position to avoid interfering with the fibers, lead it out from the fixed frame, pass through the guide device, pass through the second pre-forming fixture, and then weave it with the already threaded fibers (or join them together with a splicer). The fibers then introduce it together into the impregnation device and lead it out of the mold.

[0086] Prepare a polyurethane resin, white component (polyol), black component (isocyanate), and additives. Mix them in a ratio of 102 parts white component, 100 parts black component, and 3 parts additives, and add them to the impregnation device to fully impregnate the fibers and glass fiber fabrics inside.

[0087] After being impregnated, the fiber and glass fiber fabric enter the mold for heating and curing. The mold is equipped with three heating zones, with each zone measuring 230 mm from the mold outlet to the mold inlet. The mold heating and curing temperatures are set as follows: Zone 1: 90–120℃; Zone 2: 140–170℃; Zone 3: 180–210℃.

[0088] After the product is demolded and cooled, it is pulled by a traction device and then cut by a cutting machine according to different length requirements.

[0089] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention. Those skilled in the art, under the guidance of the present invention, can make various similar representations without departing from the spirit and claims of the present invention, and such modifications all fall within the protection scope of the present invention.

Claims

1. A method for preparing a polyurethane profile with locally reinforced materials, characterized in that, Follow these steps: S1. Design a one-time preforming tooling, which includes the following steps: S11. Calculate the cross-sectional area of ​​the polyurethane profile. Divide the cross-section of the polyurethane profile into multiple blocks according to the cross-sectional shape, and calculate the area of ​​each block. S12. Calculate the total number of fibers required to prepare the polyurethane profile, and the number of fibers required for each block; S13. Based on the cross-sectional shape and divided blocks of the polyurethane profile, map out the corresponding area of ​​the yarn-threading hole of the pre-forming tooling. Combine the number of fibers required in each area to design the number, size and arrangement of the yarn-threading holes so that the fibers passing through the yarn-threading holes can fit into the inner wall of the subsequent impregnation device and mold. S14. A gap is made in the preforming fixture to allow the reinforcing material to pass through, and the length of the gap is set to be 5%-12% larger than the width of the reinforcing material; S2. Preparation of polyurethane profiles, specifically including the following steps: S21. Arrange the glass fibers neatly on the fiber yarn rack, so that each bundle of fiber is pulled out from the yarn rack through the independent yarn-threading hole on the pre-forming tool. S22. Use a tension meter to detect the tension of each fiber bundle, and adjust the fiber tension through a tension adjustment device to control the tension of each fiber bundle so that the tension of each fiber bundle is within a preset range. S23. Allow each bundle of tension-adjusted fibers to pass through the corresponding threading holes on the pre-forming fixture. S24. The reinforcing material for local reinforcement is led out from the fixed frame, and after being initially constrained by the guiding device, it passes through the corresponding gap on the pre-forming fixture. S25. The fiber and reinforcing material are pre-formed by secondary positioning using a secondary pre-forming tooling, and then sent into the impregnation device to impregnate with resin. The secondary preforming fixture is set at the inlet of the impregnation device; or the secondary preforming fixture is set at both the inlet and outlet of the impregnation device. When a secondary preforming fixture is set only at the inlet of the impregnation device, the fibers and reinforcing materials preformed by the secondary preforming fixture are fed into the impregnation device together to impregnate the resin, and the fibers and reinforcing materials sent out from the outlet of the impregnation device directly enter the next step. When secondary preforming fixtures are set at both the inlet and outlet of the impregnation device, the fibers preformed by the secondary preforming fixture at the inlet are sent into the impregnation device to impregnate the resin. The fibers sent out from the outlet of the impregnation device, together with the reinforcing material that did not enter the impregnation device, are preformed again by the secondary preforming fixture at the outlet and then enter the next step. S26. The fibers and reinforcing materials that have undergone secondary shaping are fed into the mold cavity from the mold inlet; S27. The mold is heated in sections using a heating plate, so that the resin reacts and cures after being heated, wrapping and bonding the fibers and reinforcing materials, and then pulled out of the mold by a traction device to obtain a polyurethane profile. S3. After the polyurethane profile is cooled after demolding, cut the cooled polyurethane profile according to the required dimensions.

2. The method for preparing a polyurethane profile with locally reinforced material according to claim 1, characterized in that, In step S12, the volume V of the polyurethane profile is first calculated: V=S×L=V F + V R (1); In formula (1), S is the cross-sectional area of ​​the polyurethane profile, L is the length of the polyurethane profile, and V is the cross-sectional area of ​​the polyurethane profile. F V is the volume of the fiber. R This represents the volume of the resin. Calculate the fiber mass percentage : （2）； In equation (2), For the quality of the fiber, For the quality of the resin; Among them, the quality of the fiber Represented as: （3）； In equation (3), The glass density of the fiber; Resin quality Represented as: （4）； In equation (4), This refers to the density of the resin after curing. Fiber quality It can also be determined by the linear density of the fiber. The length L of the polyurethane profile and the number of fibers Indicate: （5）； From equations (2), (3), and (4), we can obtain: （6）； From equations (3) and (5), we can obtain: （7）； From equations (1) and (6), we can obtain: （8）； From equations (7) and (8), we can obtain: （9）； The number of fibers required to prepare the polyurethane profile and the number of fibers required for each block can be calculated using formula (9).

3. The method for preparing a polyurethane profile with locally reinforced material according to claim 1, characterized in that: In step S27, the temperature of the mold is heated to 80℃-210℃.

4. The method for preparing a polyurethane profile with locally reinforced material according to claim 1, characterized in that: In step S27, the mass percentage of fibers in the obtained polyurethane profile is 72%-85%.

5. The method for preparing a polyurethane profile with locally reinforced material according to claim 1, characterized in that: The reinforcing material is glass fiber mat or glass fiber fabric.

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