Wear-resistant flame-retardant glass fiber draw roller tube and preparation method thereof

Abstract

The present application relates to the technical field of composite material forming, and particularly relates to a wear-resistant flame-retardant glass fiber pultrusion roller tube and a preparation method, which comprises the following steps: based on driving each spindle to wind glass fiber roving on the surface of a core mold in a preset layering sequence to obtain a fiber preform; determining whether the fiber preform is qualified based on the interlacing point micro-gap rate of the fiber preform; determining whether the impregnation of the fiber preform is up to standard based on the displacement change rate and the fiber bundle displacement range value of each fiber bundle of the qualified fiber preform, and correcting the weaving tension of each spindle position when the impregnation of the fiber preform is not up to standard; and in response to the impregnation of the fiber preform being up to standard, determining the temperature change rate and the axial warping degree based on the temperature data inside the solidified forming body which has passed through the heating zone and the platform zone in sequence to optimize the first platform zone and the second platform zone, and obtaining the wear-resistant flame-retardant glass fiber pultrusion roller tube. The present application improves the uniformity of the resin impregnation of the fiber structure of the roller tube.

Description

Technical Field

[0001] This invention relates to the field of composite material molding technology, and in particular to a wear-resistant and flame-retardant glass fiber pultruded idler tube and its preparation method. Background Technology

[0002] As a core component of belt conveyors, idlers bear the crucial responsibility of supporting the conveyor belt and transporting the materials. Although small, idlers account for a significant 35% of the cost of a belt conveyor, and they also generate over 70% of the running resistance. Therefore, the flexibility and reliability of idlers are paramount, directly impacting the lifespan of the conveyor belt.

[0003] Currently, belt conveyors mainly use metal idlers. However, metal idlers have many defects during use: First, metal idlers have poor wear resistance and their surfaces are easily worn and burrs are generated. These burrs will damage the conveyor belt and cause it to be scrapped prematurely. Second, metal idlers have poor chemical corrosion resistance. When used in highly corrosive environments, their actual service life is usually less than three months. Third, metal idlers are heavy, have high running resistance, high energy consumption, and high operating noise.

[0004] Existing technologies also include solutions for manufacturing idler rollers using composite materials. Currently, most methods involve pre-impregnation followed by weaving and winding, where fibers are first impregnated with resin and then laid up and wound. However, the resin makes the fibers sticky, making it difficult to control the fiber arrangement angle and interlayer alignment during the weaving and winding process. This is especially true for multi-layer composite structures with alternating longitudinal 0° and helical 45° layups, resulting in large deviations in layup angles and uneven interlayer density. Furthermore, external atmospheric pressure impregnation makes it difficult for the resin to penetrate evenly into the inner fibers, easily leading to incomplete impregnation areas, bubbles, and dry spots. This results in poor bonding between the fiber and resin interface, reducing the product's wear resistance and service life. In addition, the continuous heating curing method concentrates the heat release during resin curing, causing a rapid accumulation of curing shrinkage stress, which can easily lead to axial warping deformation of the product. Moreover, microcracks are prone to occur at the fiber-resin interface, affecting the product's flame retardant properties and long-term service stability.

[0005] Chinese Patent Application Publication No. CN112318892A discloses a fiberglass braided pultruded spiral pipe and its preparation method, including the following technical steps: 1) lining preparation; 2) winding; 3) curing: after winding, the mold with the pipe is immediately hoisted to the curing station, and the main shaft is started to keep the mold in a uniform rotation state for curing; 4) pultrusion: the pipe in the process of curing is pulled out by a traction machine, the traction speed is synchronized with the winding speed, and is automatically controlled by a computer; 5) cutting: the pipe is cut to a set length by a cutting machine. In the lining preparation step, a reinforcing agent is added when the accelerator, curing agent and resin are mixed. The reinforcing agent is obtained by uniformly mixing nano-silica, acetone and divinyltetramethyldisiloxane platinum complex in a mass ratio of 1:4:0.05. Through the cross-linking effect of the divinyltetramethyldisiloxane platinum complex, the presence of the divinyltetramethyldisiloxane platinum complex in the reinforcing agent can prevent the separation of the inner and outer layers of the pipe.

[0006] However, the aforementioned fiberglass braided pultruded spiral pipe and its preparation method still have the following problems:

[0007] 1. If the fiber is impregnated with resin before being laid up and wound, the resin will make the fiber sticky, making it difficult to accurately control the fiber arrangement angle and interlayer arrangement during the weaving and winding process, resulting in a decrease in the mechanical properties of the product.

[0008] 2. The continuous heating curing method results in concentrated heat release during resin curing and a rapid accumulation of curing shrinkage stress, which can easily lead to axial warping and deformation of the product. Furthermore, microcracks are prone to form at the fiber-resin interface, affecting the product's flame retardancy. Summary of the Invention

[0009] Therefore, the present invention provides a wear-resistant and flame-retardant glass fiber pultruded idler tube and its preparation method, in order to overcome the problems of difficult precise control of the layup structure and uneven resin impregnation of multi-layer fiber structures in the prior art.

[0010] To achieve the above objectives, the present invention provides a method for preparing wear-resistant and flame-retardant glass fiber pultruded idler tubes, comprising:

[0011] Based on the glass fiber rovings mounted on each spindle of the braiding machine, each spindle is driven to wind layer by layer onto the surface of the mandrel in a preset layup sequence to obtain a fiber preform.

[0012] The micro-gap ratio of the interlacing points of the fiber preform is determined based on the real-time acquired surface image to determine whether the fiber preform is qualified.

[0013] In response to the fiber preform being qualified, based on the axial displacement of each fiber bundle under a preset axial traction force, the displacement change rate and displacement range of each fiber bundle are determined to determine whether the impregnation of the fiber preform is up to standard. If the impregnation of the fiber preform is not up to standard, the weaving tension of each spindle is corrected.

[0014] In response to the impregnation of the fiber preform reaching the standard, based on the temperature data inside the cured preform that sequentially passes through the first heating zone, the first platform zone, the second heating zone, the second platform zone, and the third heating zone, and based on the temperature change rate and the axial warpage of the cured preform after demolding, the duration of the first platform zone and the second platform zone is optimized to obtain a wear-resistant and flame-retardant glass fiber pultruded idler tube.

[0015] The temperature of the first heating zone is lower than that of the second heating zone, and the temperature of the second heating zone is lower than that of the third heating zone.

[0016] Furthermore, the process of determining whether the fiber preform is qualified includes:

[0017] The fiber preform is deemed qualified based on the interlacing point micro-gap ratio being greater than or equal to a first preset interlacing point micro-gap ratio and less than or equal to a second preset interlacing point micro-gap ratio.

[0018] Based on the interlacing point microgap ratio being less than the first preset interlacing point microgap ratio or greater than the second preset interlacing point microgap ratio, the fiber preform is determined to be unqualified and the weaving tension of each spindle is adjusted.

[0019] Wherein, the interlacing point microgap rate is the ratio of the sum of the areas of all gap regions within the preset measurement length to the surface area corresponding to the preset measurement length.

[0020] Furthermore, the process of determining whether the impregnation of the fiber preform meets the standards includes:

[0021] Based on the fact that the displacement change rate of any fiber bundle is less than or equal to the preset displacement change rate, and the displacement range of the fiber bundle is less than or equal to the preset displacement range of the fiber bundle, it is determined that the impregnation of the fiber preform meets the standard.

[0022] If the displacement change rate of any fiber bundle is greater than the preset displacement change rate, or the displacement range of the fiber bundle is greater than the preset displacement range of the fiber bundle, it is determined that the impregnation of the fiber preform is substandard and the weaving tension of each spindle is corrected.

[0023] The displacement change rate is the rate of change of the axial displacement of the fiber bundle with time, which is determined by dividing the difference between the axial displacement at the current moment and the axial displacement at the previous moment by the sampling time interval.

[0024] The displacement range is the difference between the maximum and minimum axial displacements of all fiber bundles at the same moment.

[0025] Furthermore, the process of adjusting the weaving tension at each spindle position includes:

[0026] In response to the defect of the fiber preform, based on the fact that the micro-gap ratio of the interlacing point is less than the first preset micro-gap ratio of the interlacing point, it is determined to reduce the weaving tension of each spindle.

[0027] The reduction in weaving tension is positively correlated with a first difference, which is determined based on a first preset interlacing point microgap ratio and an interlacing point microgap ratio.

[0028] Furthermore, the process of adjusting the weaving tension at each spindle position also includes:

[0029] Based on the fact that the micro-gap ratio at the interlacing point is greater than the second preset micro-gap ratio at the interlacing point, the braiding tension at each spindle position is increased; wherein, the increase in the braiding tension is positively correlated with the second difference, and the second difference is determined based on the second preset micro-gap ratio at the interlacing point and the micro-gap ratio at the interlacing point.

[0030] Furthermore, the process of correcting the weaving tension at each spindle position includes:

[0031] Based on the fact that the displacement change rate of a single fiber bundle is greater than the preset displacement change rate, or based on the fact that the displacement range of the fiber bundle is greater than the preset displacement range of the fiber bundle and the displacement of a single fiber bundle is greater than the average displacement of all fiber bundles, the weaving tension of the corresponding spindle position is increased by an adjustment coefficient.

[0032] Furthermore, the process of correcting the weaving tension at each spindle position also includes:

[0033] Based on the fact that the fiber bundle displacement range is greater than the preset fiber bundle displacement range, and the displacement of a single fiber bundle is less than the average displacement of all fiber bundles, it is determined that the weaving tension of the corresponding spindle position will be reduced by an adjustment coefficient.

[0034] Furthermore, the process of optimizing the first platform region and the second platform region includes:

[0035] Based on the fact that the rate of temperature change at any monitoring point in the first platform area or the second platform area is greater than the preset rate of temperature change, it is determined to extend the duration of the first platform area or the duration of the second platform area by an extension coefficient.

[0036] The temperature change rate is the amount of temperature change per unit time, which is determined by the rate of change of temperature data at monitoring points over time.

[0037] Furthermore, the process of optimizing the first platform region and the second platform region also includes:

[0038] Based on the fact that the axial warp is greater than the preset axial warp and the temperature change rate at any monitoring point is less than or equal to the preset temperature change rate, it is determined that the duration of the second platform area will be extended by the third extension coefficient.

[0039] The axial warpage is determined based on the maximum value of the offset of each measurement point relative to the line connecting the two ends.

[0040] On the other hand, the present invention also provides a wear-resistant and flame-retardant glass fiber pultruded idler tube, wherein the idler tube is composed of glass fiber and matrix resin, wherein...

[0041] The glass fiber is E glass fiber or S glass fiber, and the matrix resin is bisphenol A epoxy resin or vinyl ester resin.

[0042] The mass ratio of the glass fiber to the matrix resin is (60-80):(40-20).

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention solves the problems of layup angle deviation and uneven interlayer density caused by fiber stickiness in the pre-impregnation process by dry weaving and real-time detection of micro-gaps at interlacing points; overcomes the defects of poor interface bonding caused by fiber skeleton slippage and twisting during resin injection by monitoring the fiber bundle displacement change rate and range value and tension correction; achieves the phased release of curing exothermics and gradual relaxation of shrinkage stress through gradient curing in the plateau region, reducing the risk of axial warping deformation of the product; and optimizes the plateau region duration based on the joint feedback of temperature change rate and axial warping, avoiding product quality fluctuations caused by fixed process parameters.

[0044] Furthermore, this invention utilizes a dry weaving and winding process to complete the layup of glass fiber roving without any contact with resin. This avoids the problems of resin causing fiber stickiness and difficulty in controlling the layup angle and interlayer arrangement, which are common in pre-impregnation processes. By identifying fiber interlacing points and calculating the micro-gap ratio at these points, the invention achieves quantitative characterization of layup density. This avoids excessive resin flow resistance due to overly dense layups or loose fiber structure due to overly loose layups, providing a structurally stable fiber skeleton for resin impregnation and thus improving the stability of the product's mechanical properties.

[0045] Furthermore, by applying a preset axial traction force to each fiber bundle and monitoring the axial displacement of each fiber bundle in real time, the present invention calculates the displacement change rate of each fiber bundle and the displacement range of all fiber bundles, thereby achieving a quantitative characterization of the structural stability of the fiber skeleton during resin flow. This avoids the fiber bundles from slipping or twisting under resin impact. By adjusting the weaving tension of the corresponding spindle position, it avoids poor interfacial bonding caused by fiber bundle displacement, reduces the occurrence rate of internal defects in the product, and improves the interfacial bonding quality between the fiber and the resin.

[0046] Specifically, this invention combines stepped curing with segmented control of the platform zone, allowing the impregnated fiber preform to pass sequentially through a first heating zone, a first platform zone, a second heating zone, a second platform zone, and a third heating zone. This achieves the phased release of resin curing heat and the gradual relaxation of curing shrinkage stress, avoiding the rapid accumulation of internal stress caused by concentrated resin heat release in continuous heating curing methods. This reduces the risk of axial warping deformation of the product, minimizes the generation of microcracks at the fiber-resin interface, improves the dimensional stability and interfacial bonding strength of the product, and extends the product's service life.

[0047] Furthermore, by monitoring the temperature change rate at multiple points during the curing process, the present invention achieves online evaluation of the curing reaction uniformity. Based on the joint optimization of the plateau duration using the temperature change rate and axial warpage, the invention avoids product quality fluctuations caused by fixed process parameters, thereby reducing the scrap rate and improving the dimensional accuracy of the product. Attached Figure Description

[0048] Figure 1 This is a flowchart illustrating the steps of the wear-resistant and flame-retardant glass fiber pultruded idler tube and its preparation method in an embodiment of the present invention.

[0049] Figure 2 This is a logic diagram for determining whether the fiber preform is qualified according to an embodiment of the present invention;

[0050] Figure 3 This is a logic diagram for determining whether the impregnation of the fiber preform meets the standard in an embodiment of the present invention;

[0051] Figure 4 A flowchart illustrating the steps for optimizing the first platform region and the second platform region in an embodiment of the present invention. Detailed Implementation

[0052] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0053] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0054] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0055] Please see Figure 1 The diagram shown is a flowchart illustrating the steps of the wear-resistant and flame-retardant glass fiber pultruded idler tube and its preparation method in an embodiment of the present invention.

[0056] This invention relates to a wear-resistant and flame-retardant glass fiber pultruded idler roller tube and its preparation method, comprising:

[0057] Step S1: Based on the glass fiber rovings mounted on each spindle of the braiding machine, drive each spindle to wind layer by layer onto the surface of the mandrel in a preset layup sequence to obtain a fiber preform.

[0058] Step S2: Determine the micro-gap ratio of the interlacing points of the fiber preform based on the real-time acquired surface image, so as to determine whether the fiber preform is qualified;

[0059] Step S3: In response to the fiber preform being qualified, based on the axial displacement of each fiber bundle under the applied preset axial traction force, determine the displacement change rate and displacement range of each fiber bundle to determine whether the impregnation of the fiber preform meets the standard. If the impregnation of the fiber preform does not meet the standard, the weaving tension of each spindle is corrected.

[0060] Step S4: In response to the impregnation of the fiber preform reaching the standard, based on the temperature data inside the cured preform that has passed through the first heating zone, the first platform zone, the second heating zone, the second platform zone and the third heating zone in sequence, and based on the temperature change rate and the axial warpage of the cured preform after demolding, the duration of the first platform zone and the second platform zone is optimized to obtain a wear-resistant and flame-retardant glass fiber pultruded idler tube.

[0061] The temperature of the first heating zone is lower than that of the second heating zone, and the temperature of the second heating zone is lower than that of the third heating zone, forming a gradient heating and curing process.

[0062] Specifically, this invention solves the problems of layup angle deviation and uneven interlayer density caused by fiber stickiness in the pre-impregnation process by dry weaving and real-time detection of micro-gaps at interlacing points. By monitoring the fiber bundle displacement change rate and range and tension correction, it overcomes the defects of poor interfacial bonding caused by fiber skeleton slippage and twisting during resin injection. Through gradient curing in the plateau region, it realizes the phased release of curing exothermics and the gradual relaxation of shrinkage stress, reducing the risk of axial warping deformation of the product. Based on the joint feedback of temperature change rate and axial warping, the duration of the plateau region is optimized, avoiding product quality fluctuations caused by fixed process parameters.

[0063] In this embodiment of the invention, the preset layup sequence is to alternately lay longitudinal 0° layers and spiral 45° layers from the inside out, repeating N times until the design requirements for layup thickness are met.

[0064] Please see Figure 2 As shown, it is a logic diagram for determining whether the fiber preform is qualified according to an embodiment of the present invention.

[0065] Specifically, during the weaving process of the fiber preform, images of the surface of the fiber preform are acquired in real time to calculate the micro-gap ratio at the interlacing points and determine whether the fiber preform is qualified.

[0066] The interlacing point microgap ratio is compared with the first preset interlacing point microgap ratio and the second preset interlacing point microgap ratio, respectively;

[0067] If the micro-gap ratio of the interlacing point is greater than or equal to the first preset interlacing point micro-gap ratio and less than or equal to the second preset interlacing point micro-gap ratio, then the fiber preform is determined to be qualified.

[0068] If the micro-gap ratio at the interlacing point is less than the first preset micro-gap ratio at the interlacing point, or greater than the second preset micro-gap ratio at the interlacing point, then the fiber preform is determined to be unqualified.

[0069] In this embodiment of the invention, the measurement process of the interlacing point microgap ratio is as follows: an online laser profile scanning device is used to continuously scan along the axial direction of the fiber preform at a scanning speed of 10 mm / s to 20 mm / s, and a cross-sectional profile data is recorded at every 1 mm to 2 mm interval. The fiber interlacing points on each cross-sectional profile are identified by an image processing algorithm. The gap region between adjacent fiber bundles is extracted at each interlacing point, and the area of ​​the gap region is calculated. The ratio of the sum of the areas of all gap regions within the preset measurement length to the surface area corresponding to the preset measurement length is determined as the interlacing point microgap ratio.

[0070] In this embodiment of the invention, the interlacing point microgap ratio is determined by the following formula:

[0071]

[0072] in, The interlacing point microgap ratio, Let m be the area of ​​the closed region enclosed by the gaps between adjacent fiber bundles at the j-th interlacing point, m be the total number of interlacing points identified within the preset measurement length, and S be the outer surface area of ​​the fiber preform corresponding to the preset measurement length. The preset measurement length is in the range of 200mm to 500mm, and is preferably set to 250mm.

[0073] In this embodiment of the invention, the value range of the first preset interlacing point micro-gap ratio is 0.5% to 2%, preferably set to 1%, and the value range of the second preset interlacing point micro-gap ratio is 3% to 8%, preferably set to 5%. The selection is based on the following: under the conditions of a preset measurement length of 250 mm and a scanning speed of 15 mm / s, an online laser contour scanning device is used to measure several fiber preforms, and the resin wetting effect and product performance corresponding to different interlacing point micro-gap ratios are statistically analyzed. When the interlacing point micro-gap ratio is less than 1%, the fiber bundles are excessively compressed, and the fibers... If the preform is too dense, the resin flow resistance during resin impregnation will be too high, which will easily create areas of incomplete impregnation. This will result in poor bonding between the fiber and resin interface after curing, and a decrease in wear resistance. When the micro-porosity of the interlacing point is less than 5%, the gap between the fiber bundles will be too large, the fiber preform structure will be loose, and a resin-rich area will easily form during resin impregnation. After curing, the resin-rich area will have low hardness and be easily worn. In addition, the flame retardant will accumulate in the resin-rich area, resulting in uneven char formation during combustion and a decrease in flame retardant performance. However, the above values ​​are not limited to these, and those skilled in the art can adjust the values ​​according to actual needs.

[0074] Specifically, this invention utilizes a dry weaving and winding process to lay up glass fiber rovings without any contact with resin. This avoids the problems of resin causing fiber stickiness and difficulty in controlling layup angle and interlayer arrangement that occur in the pre-impregnation process. Furthermore, by identifying fiber interlacing points and calculating the micro-gap ratio at these points, the invention achieves quantitative characterization of layup density. This avoids excessive resin flow resistance due to overly dense layups or loose fiber structure due to overly loose layups, providing a structurally stable fiber skeleton for resin impregnation and thus improving the stability of the product's mechanical properties.

[0075] Specifically, the process of adjusting the weaving tension of each spindle in response to the defect of the fiber preform includes:

[0076] If the interlacing point gap ratio is less than the first preset interlacing point gap ratio, then the weaving tension of each spindle position is reduced.

[0077] If the interlacing point gap ratio is greater than the second preset interlacing point gap ratio, then the weaving tension of each spindle position is increased.

[0078] In this embodiment of the invention, the reduction in weaving tension is positively correlated with the first difference. The reduction in weaving tension is determined by the product of a first preset tension correction coefficient and the first difference. The first difference is the difference between the first preset interlacing point microgap ratio and the interlacing point microgap ratio.

[0079] In this embodiment of the invention, the increase in the weaving tension is positively correlated with the second difference. The increase in the weaving tension is determined by the product of the second preset tension correction coefficient and the second difference. The second difference is the difference between the interlacing point microgap ratio and the second preset interlacing point microgap ratio.

[0080] In this embodiment of the invention, the value range of the first preset tension correction coefficient is 0.5N / % to 1.5N / %, preferably set to 1.0N / %, and the value range of the second preset tension correction coefficient is 0.5N / % to 1.5N / %, preferably set to 1.0N / %. However, the above values ​​are not limited to these, and those skilled in the art can adjust the values ​​according to actual needs.

[0081] It is understood that the first preset tension correction coefficient and the second preset tension correction coefficient are determined in the following way: Under the conditions of a preset measurement length of 250 mm and a scanning speed of 15 mm / s, an online laser contour scanning device is used to measure the fiber preform, record the interlacing point micro-gap ratio under different weaving tensions, and statistically analyze the correspondence between the interlacing point micro-gap ratio and the change in weaving tension: When the first difference is 1%, a reduction of 1.0 N in weaving tension can cause the interlacing point micro-gap ratio to rise from 0.8% to 1.2%, indicating that a correction coefficient of 1.0 N / % can achieve effective adjustment; when the second difference is 1%, an increase of 1.0 N in weaving tension can cause the interlacing point micro-gap ratio to decrease from 5.2% to 4.8%; through several batches of experiments, the correction coefficient range of 0.5 N / % to 1.5 N / % can cover the adjustment requirements under different layup thicknesses and fiber specifications, but the above values ​​are not limited to this, and those skilled in the art can adjust the values ​​according to actual needs.

[0082] In this embodiment of the invention, the axial displacement of each fiber bundle is obtained by the following method: a set of laser displacement sensors is set between the outlet of the braiding machine and the inlet of the curing mold, each sensor is aligned with a fiber bundle, the distance between the sensor and the fiber bundle is 50mm to 80mm, the sampling frequency is 100Hz to 200Hz, and the axial position of each fiber bundle is recorded in real time over time to obtain the axial displacement versus time curve of each fiber bundle.

[0083] Specifically, the rate of change of displacement of each fiber bundle is determined by the following formula:

[0084]

[0085] in, Let be the rate of change of displacement of the i-th fiber bundle. Let be the axial displacement of the i-th fiber bundle at time t. This represents the sampling time interval.

[0086] Specifically, the fiber bundle displacement range is determined by the following formula:

[0087]

[0088] in, This represents the range of fiber bundle displacement. This represents the maximum axial displacement of all fiber bundles at the same moment. It represents the minimum axial displacement of all fiber bundles at the same moment.

[0089] In this embodiment of the invention, the preset axial traction force ranges from 1N to 5N, preferably set to 3N. The value is determined based on the following: under the conditions of a traction rate of 0.05m / min and an injection pressure of 0.3MPa, immersion tests are conducted with axial traction forces of 0.5N, 1N, 2N, 3N, 4N, 5N, and 6N, respectively. The signal stability of the laser displacement sensor is recorded, and the displacement of the fiber bundle during resin flow is observed. When the traction force is less than 1N, the signal-to-noise ratio of the displacement signal obtained by the laser displacement sensor is less than 10dB, making it impossible to stably monitor the axial displacement of the fiber bundle. When the traction force is greater than 5N, the fiber bundle has been overstretched before resin injection, resulting in micro-deformation of the fiber preform structure. When the traction force is within the range of 1N to 5N, the traction force is only used to monitor the dynamic response of the fiber bundle during resin flow and will not affect the structure of the fiber preform, while ensuring that the laser displacement sensor obtains a stable displacement signal.

[0090] Specifically, this invention applies a preset axial traction force to each fiber bundle and monitors the axial displacement of each fiber bundle in real time, calculates the displacement change rate of each fiber bundle and the displacement range of all fiber bundles, thereby achieving a quantitative characterization of the structural stability of the fiber skeleton during resin flow. This avoids the fiber bundles from slipping or twisting under resin impact, and by adjusting the weaving tension of the corresponding spindle position, it avoids poor interfacial bonding caused by fiber bundle displacement, reduces the generation rate of internal defects in the product, and improves the interfacial bonding quality between the fiber and the resin.

[0091] Please see Figure 3 As shown, it is a logic judgment diagram for determining whether the impregnation of the fiber preform meets the standard in an embodiment of the present invention.

[0092] Specifically, the wetting of the fiber preform is determined based on the displacement change rate and the fiber bundle displacement range;

[0093] The displacement change rate of each fiber bundle is compared with the preset displacement change rate, and the displacement range of the fiber bundle is compared with the preset displacement range of the fiber bundle.

[0094] If the displacement change rate of each fiber bundle is less than or equal to the preset displacement change rate and the displacement range of the fiber bundle is less than or equal to the preset displacement range of the fiber bundle, then the impregnation of the fiber preform is determined to be up to standard.

[0095] If the displacement change rate of each fiber bundle is greater than the preset displacement change rate, or the displacement range of the fiber bundle is greater than the preset displacement range of the fiber bundle, then the impregnation of the fiber preform is determined to be substandard.

[0096] In this embodiment of the invention, the preset displacement change rate ranges from 0.005 mm / s to 0.02 mm / s, preferably 0.01 mm / s; the preset displacement range ranges from 0.03 mm to 0.08 mm, preferably 0.05 mm. The values ​​are determined based on the following: under conditions of a traction rate of 0.05 m / min and an injection pressure of 0.3 MPa, a laser displacement sensor is used to monitor the axial displacement of the fiber bundle, and the interface quality of the cured molded body corresponding to different displacement change rates and displacement ranges is recorded simultaneously; when the displacement change rate is ≤0.01 mm / s... When the displacement range is ≤0.05mm, there are no microcracks at the interface after curing, and the fiber and resin are well bonded. When the displacement change rate is >0.01mm / s or the displacement range is >0.05mm, microcracks appear at the interface after curing, and the interface bonding strength decreases by more than 20%. Through several experiments, it has been verified that the ranges of 0.005mm / s to 0.02mm / s and 0.03mm to 0.08mm can cover the structural stability control requirements under different fiber specifications and layup thicknesses. However, the above values ​​are not limited to these values, and those skilled in the art can adjust the values ​​according to actual needs.

[0097] Specifically, under the condition that the impregnation of the fiber preform is not up to standard, the weaving tension of each spindle is corrected;

[0098] If the displacement change rate of each fiber bundle is greater than the preset displacement change rate, then the weaving tension of the corresponding spindle position of the fiber bundle is increased to the corresponding value by the first adjustment coefficient.

[0099] If the displacement change rate of each fiber bundle is greater than the preset displacement change rate, then the weaving tension of all spindles is increased to the corresponding value by the second adjustment coefficient.

[0100] If the fiber bundle displacement range is greater than the preset fiber bundle displacement range, the weaving tension of each spindle is adjusted differentially according to the displacement value of each fiber bundle:

[0101] If the displacement of a single fiber bundle is greater than the average displacement of all fiber bundles, then the weaving tension of the corresponding spindle position is increased to the corresponding value by the third adjustment coefficient.

[0102] If the displacement of a single fiber bundle is less than the average displacement of all fiber bundles, then the weaving tension of the corresponding spindle position is reduced to the corresponding value by the fourth adjustment coefficient.

[0103] In this embodiment of the invention, the current weaving tension for maintaining the corresponding spindle position is determined based on the fact that the displacement of a single fiber bundle is equal to the average displacement of all fiber bundles.

[0104] In this embodiment of the invention, the first adjustment coefficient ranges from 1 N·s / mm to 3 N·s / mm, preferably 2 N·s / mm; the second adjustment coefficient ranges from 1 N·s / mm to 3 N·s / mm, preferably 2 N·s / mm; the third adjustment coefficient ranges from 0.5 N / mm to 1.5 N / mm, preferably 1 N / mm; and the fourth adjustment coefficient ranges from 0.5 N / mm to 1.5 N / mm, preferably 1 N / mm. The values ​​are determined based on the following conditions: at a traction rate of 0.05 m / min and an injection pressure of 0.3 MPa... Under the given conditions, the tension correction effect corresponding to different adjustment coefficients was tested. When the first adjustment coefficient was 2.0 N·s / mm, the tension increased by 0.01 N for every 0.005 mm / s increase in the displacement change rate deviation, enabling the fiber bundle displacement to recover to a stable state within 3 seconds. When the third adjustment coefficient was 1.0 N / mm, the tension increased by 0.1 N for every 0.1 mm increase in the displacement deviation, effectively suppressing the differential displacement of the fiber bundle. Through several experiments, rapid and stable tension correction can be achieved. However, the above values ​​are not limited to these values, and those skilled in the art can adjust the values ​​according to actual needs.

[0105] In this embodiment of the invention, the first increase in the weaving tension is determined by the product of the first adjustment coefficient and the displacement change rate deviation value, wherein the displacement change rate deviation value is the difference between the displacement change rate of the fiber bundle and the preset displacement change rate.

[0106] In this embodiment of the invention, the second increase in the weaving tension is determined by the product of the second adjustment coefficient and the arithmetic mean deviation of the displacement change rate, wherein the arithmetic mean deviation of the displacement change rate is the difference between the arithmetic mean of the displacement change rates of each fiber bundle and the preset displacement change rate.

[0107] In this embodiment of the invention, the third increase in the weaving tension is determined by the product of the third adjustment coefficient and the displacement deviation, wherein the displacement deviation is the difference between the displacement of the fiber bundle and the average displacement of each fiber bundle.

[0108] In this embodiment of the invention, the first reduction in the weaving tension is determined by the product of the fourth adjustment coefficient and the displacement deviation.

[0109] In this embodiment of the invention, for example, the temperature of the first heating zone is 70℃~90℃, preferably 80℃, the temperature of the second heating zone is 100℃~150℃, preferably 125℃, and the temperature of the third heating zone is 150℃~200℃, preferably 175℃.

[0110] In this embodiment of the invention, the first platform area is an isothermal holding stage set between the first heating area and the second heating area, wherein the temperature is maintained at 80°C to 100°C for a duration of 5 min to 15 min.

[0111] In this embodiment of the invention, the second platform area is an isothermal holding stage set between the second heating area and the third heating area, wherein the temperature is maintained at 120°C to 140°C for a duration of 10 min to 20 min.

[0112] It is understood that the first and second platform zones are realized during the continuous pultrusion process. Specifically, in the curing mold, a first heating zone, a first platform zone, a second heating zone, a second platform zone, and a third heating zone are sequentially set along the traction direction. Each section maintains its set temperature through an independent heating control system. The fiber preform continuously passes through each section under traction. In the first and second platform zones, since the temperature remains constant and there is no temperature rise, the resin obtains sufficient isothermal reaction time, thereby realizing the phased release of curing exothermics and the gradual relaxation of curing shrinkage stress.

[0113] In this embodiment of the invention, the first plateau region allows the resin to flow fully and expel air bubbles at a lower temperature, thereby improving the density of the resin impregnation. The second plateau region allows the resin to slowly crosslink at a moderate temperature, releasing curing shrinkage stress and avoiding interfacial peeling caused by excessive curing shrinkage stress.

[0114] Specifically, this invention combines stepped curing with segmented control of the platform zone, allowing the impregnated fiber preform to pass sequentially through a first heating zone, a first platform zone, a second heating zone, a second platform zone, and a third heating zone. This achieves the phased release of resin curing heat and the gradual relaxation of curing shrinkage stress, avoiding the rapid accumulation of internal stress caused by concentrated resin heat release in continuous heating curing methods. This reduces the risk of axial warping deformation of the product, minimizes the generation of microcracks at the fiber-resin interface, improves the dimensional stability and interfacial bonding strength of the product, and extends the product's service life.

[0115] Please see Figure 4As shown, it is a flowchart of the steps for optimizing the first platform area and the second platform area in an embodiment of the present invention.

[0116] Specifically, during the curing process, the temperature data inside the cured molded body is acquired in real time to calculate the temperature change rate. Based on the temperature change rate and the axial warpage of the cured molded body after demolding, the first platform area and the second platform area are optimized to obtain a wear-resistant and flame-retardant glass fiber pultruded idler tube.

[0117] Step S41: Compare the temperature change rate at each monitoring point with the preset temperature change rate, and compare the axial warpage with the preset axial warpage.

[0118] Step S42: If the temperature change rate at any monitoring point in the first platform area is greater than the preset temperature change rate, then determine to extend the duration of the first platform area to the corresponding value by the first extension coefficient.

[0119] Step S43: If the temperature change rate of all monitoring points in the first platform area is less than or equal to the preset temperature change rate, then determine the current duration of maintaining the first platform area.

[0120] Step S44: If the temperature change rate at any monitoring point in the second platform area is greater than the preset temperature change rate, then determine to extend the duration of the second platform area to the corresponding value by the second extension coefficient.

[0121] Step S45: If the temperature change rate of all monitoring points in the second platform area is less than or equal to the preset temperature change rate, then determine the current duration of maintaining the second platform area.

[0122] Step S46: If the axial warp is greater than the preset axial warp and the temperature change rate at any monitoring point is less than or equal to the preset temperature change rate, then determine to extend the duration of the second platform area to the corresponding value by the third extension coefficient.

[0123] Step S47: If the axial warp is less than or equal to the preset axial warp, and the temperature change rate of all monitoring points is less than or equal to the preset temperature change rate, then determine the current duration of maintaining the first platform area and the second platform area.

[0124] In this embodiment of the invention, the extension value of the first platform area is determined by the product of the first extension coefficient and the first temperature change rate deviation value, wherein the first temperature change rate deviation value is the difference between the temperature change rate of the monitoring point in the first platform area and the preset temperature change rate.

[0125] In this embodiment of the invention, the extension value of the second platform area is determined by the product of the second extension coefficient and the second temperature change rate deviation value, wherein the second temperature change rate deviation value is the difference between the temperature change rate of the monitoring point in the second platform area and the preset temperature change rate.

[0126] In this embodiment of the invention, the extension value of the second platform region is determined by the product of the third extension coefficient and the axial warping deviation value, wherein the axial warping deviation value is the difference between the axial warping and the preset axial warping.

[0127] In this embodiment of the invention, the value range of the first elongation coefficient is 1 min / (℃ / min) to 3 min / (℃ / min), preferably 2 min / (℃ / min); the value range of the second elongation coefficient is 1 min / (℃ / min) to 3 min / (℃ / min), preferably 2 min / (℃ / min); and the value range of the third elongation coefficient is 5 min / (mm / m) to 15 min / (mm / m), preferably 10 min / (mm / m). The value range is determined by testing the plateau period elongation effect corresponding to different elongation coefficients under the conditions of a traction rate of 0.05 m / min, a plateau temperature of 80 to 140℃, and a curing temperature of 150 to 200℃. However, the above values ​​are not limited to these, and those skilled in the art can adjust the values ​​according to actual needs.

[0128] In this embodiment of the invention, during the curing process, a temperature sensor is set every 50mm to 100mm along the axial direction of the curing mold to monitor the temperature change inside the resin in real time, and the temperature change rate of each monitoring point is calculated every 5 seconds.

[0129] In this embodiment of the invention, the demolded and cured molded body is placed horizontally on a precision platform, and laser displacement sensors are set as measurement points every 100mm along the axial direction to measure the radial offset. The offset of each measurement point relative to the line connecting the two ends is calculated, and the maximum value is taken as the axial warpage.

[0130] In this embodiment of the invention, the preset temperature change rate is 2℃ / min, and the preset axial warpage is 0.5mm / m. The values ​​are determined as follows: under the conditions of a traction rate of 0.05m / min, a platform area temperature of 80-140℃, and a curing temperature of 150-200℃, curing tests are conducted at temperature change rates of 1.0℃ / min, 1.5℃ / min, 2.0℃ / min, 2.5℃ / min, and 3.0℃ / min, respectively. The axial warpage of the cured molded body is measured simultaneously, and the interface microcracks are observed using a scanning electron microscope. Wear resistance and flame retardant performance tests are also performed to determine the results. However, the above values ​​are not limited to these, and those skilled in the art can adjust the values ​​according to actual needs.

[0131] Specifically, this invention achieves online evaluation of curing reaction uniformity by monitoring the temperature change rate at multiple points during the curing process. Based on the joint optimization of the plateau period duration based on the temperature change rate and axial warpage, it avoids product quality fluctuations caused by fixed process parameters, thereby reducing scrap rate and improving product dimensional accuracy.

[0132] On the other hand, the present invention provides a wear-resistant and flame-retardant glass fiber pultruded idler tube, wherein the idler tube is composed of glass fiber and matrix resin, wherein...

[0133] The glass fiber is E glass fiber or S glass fiber, the matrix resin is bisphenol A epoxy resin or vinyl ester resin, and the mass ratio of the glass fiber to the matrix resin is (60-80):(40-20), preferably 72:28.

[0134] In this embodiment of the invention, for every 0.5 mm increase in the layup thickness, a layup combination with a longitudinal angle of 0° and a spiral angle of 45° is added. The ratio of the longitudinal glass fiber roving to the spiral glass fiber roving in each combination is 1:1.

[0135] In this embodiment of the invention, the glass fiber roving is 2400Tex E glass fiber, and the matrix resin contains a phosphorus-based flame retardant and a wear-resistant filler uniformly dispersed. The amount of the phosphorus-based flame retardant triethyl phosphate added is 15% of the resin mass, and the amount of the wear-resistant filler nano alumina added is 5% of the resin mass.

[0136] Example 1

[0137] Using 2400Tex E-glass fiber roving, according to the design requirements for layup thickness, the number of layup combinations of longitudinal 0° layer and spiral 45° layer is determined to be N=4, and the total layup thickness is 8mm. The glass fiber roving is hung on each spindle of the braiding machine in a symmetrical arrangement of the same specification. Each spindle is driven at a preset braiding speed, and the glass fiber roving is wound layer by layer on the surface of the mandrel in an alternating layup sequence of longitudinal 0° layer and spiral 45° layer from the inside out to obtain a fiber preform.

[0138] During the weaving process, an online laser contour scanning device is used to continuously scan along the axial direction of the fiber preform at a scanning speed of 15 mm / s. A cross-sectional contour data is recorded every 1.5 mm. The fiber interlacing points on each cross-sectional contour are identified by an image processing algorithm, and the micro gap rate of the interlacing points is calculated. The measured micro gap rate of the interlacing points is 2.5%, which is greater than the first preset micro gap rate of 1% and less than the second preset micro gap rate of 5%, so the fiber preform is qualified.

[0139] The qualified fiber preform is pulled into the curing mold at a first preset traction rate of 0.05 m / min. When it enters the curing mold, bisphenol A type epoxy resin, which contains 15% triethyl phosphate flame retardant and 5% nano alumina wear-resistant filler by weight of resin, is injected into the curing mold at a preset injection pressure of 0.3 MPa.

[0140] During the resin injection process, a preset axial traction force of 3N is applied to each fiber bundle, and a set of laser displacement sensors is set between the braiding machine outlet and the curing mold inlet to monitor the axial displacement of each fiber bundle in real time. The average displacement change rate of each fiber bundle is 0.008mm / s, which is less than the preset displacement change rate of 0.01mm / s, and the fiber bundle displacement range is 0.04mm, which is less than the preset fiber bundle displacement range of 0.05mm, thus confirming that the impregnation meets the standard.

[0141] The fiber preform that has been impregnated to the standard is pulled through the curing mold at a second preset traction rate of 0.05 m / min, and then passes through the first heating zone at 80°C, the first platform zone at 90°C for 10 min, the second heating zone at 120°C, the second platform zone at 130°C for 15 min, and the third heating zone at 170°C to obtain the cured preform.

[0142] During the curing process, a temperature sensor is set every 80mm along the axial direction of the curing mold to monitor the temperature change inside the resin in real time. The temperature change rate of each monitoring point is calculated every 10s. The temperature change rate of each monitoring point is ≤2℃ / min, and there is no need to adjust the duration of the platform area.

[0143] After demolding, the cured molded body is placed horizontally on a precision platform. A laser displacement sensor is set every 100mm along the axial direction to measure the radial offset. The axial warpage is 0.3mm / m, which is less than the preset axial warpage of 0.5mm / m. The product dimensional accuracy is qualified, and wear-resistant and flame-retardant glass fiber pultruded idler tube is obtained.

[0144] In this embodiment of the invention, based on the design wall thickness of 8mm and fiber layup structure of the idler roller tube, the mass ratio of glass fiber to matrix resin is 72:28, and the measured mass fraction of resin in the cured molded body is 28%±2%.

[0145] In this embodiment of the invention, the product prepared in Example 1 is used. The 152×8×200mm glass fiber pultruded idler tube was used as the test sample for flame retardancy testing, load-bearing capacity testing, weight comparison, and service life evaluation.

[0146] Table 1 Flame retardant performance test results

[0147]

[0148] In this embodiment of the invention, a combustion test was conducted according to the GB / T 2406-2009 standard, and 10 samples prepared in Example 1 were taken. Flame retardancy performance of 152×8×200mm glass fiber pultruded idler tubes was tested.

[0149] In this embodiment of the invention, a pressure test was conducted according to the GB / T 5350-2008 standard. A universal testing machine was used to apply a radial load to the idler roller tube. The test results showed that the material prepared in Example 1... The 152×8×200mm glass fiber pultruded idler tube can withstand a force of 8255N without damage. When the tube body is pressed down by 6mm, there are no cracks on the surface and the diameter deformation is ≤0.5mm, indicating that it has excellent structural strength and resistance to deformation.

[0150] In this embodiment of the invention, the weight of the fiberglass roller tube prepared in Example 1 is 1.52 kg, while the weight of the steel roller tube of the same specification is 5.64 kg. The fiberglass roller tube is 26.84% lighter than the steel roller tube.

[0151] In this embodiment of the invention, when steel idler tubes are used in highly corrosive environments, their actual service life is usually less than three months, and the steel fibers generated by wear will seriously damage the conveyor belt. The fiberglass idler tubes prepared in this embodiment 1 have been verified by accelerated aging tests to have a service life that can be increased by more than 50%, and have excellent chemical corrosion resistance. At the same time, the fiberglass will not damage the belt.

[0152] Example 2

[0153] Using 2400Tex E-grade glass fiber roving, and according to the layup thickness design requirements, the number of layup combinations N=4 (0° longitudinal layer and 45° spiral layer), with a total layup thickness of 8mm. The glass fiber roving is symmetrically arranged on each spindle of the braiding machine, and each spindle is driven at a preset braiding speed. The glass fiber roving is wound layer by layer onto the surface of the mandrel, alternating between the 0° longitudinal layer and the 45° spiral layer from the inside out, to obtain a fiber preform.

[0154] During the weaving process, an online laser contour scanning device is used to continuously scan along the axial direction of the fiber preform at a scanning speed of 15 mm / s. Cross-sectional contour data is recorded at 1.5 mm intervals. Image processing algorithms are used to identify fiber interlacing points on each cross-sectional contour, and the micro-gap ratio of these interlacing points is calculated. Measurements show that the micro-gap ratio is 2.6%, which is greater than the first preset micro-gap ratio of 1% and less than the second preset micro-gap ratio of 5%, indicating that the fiber preform is qualified.

[0155] The qualified fiber preform is drawn into the curing mold at a first preset traction rate of 0.05 m / min. Upon entering the curing mold, bisphenol A epoxy resin (containing 15% triethyl phosphate flame retardant and 5% nano-alumina wear-resistant filler by weight of resin) is injected into the curing mold at a preset injection pressure of 0.3 MPa. By adjusting the flow rate of the resin metering pump, the final mass ratio of glass fiber to matrix resin is controlled at 60:40.

[0156] During resin injection, a preset axial traction force of 3N is applied to each fiber bundle, and a set of laser displacement sensors is installed between the braiding machine outlet and the curing mold inlet to monitor the axial displacement of each fiber bundle in real time. The average displacement change rate of each fiber bundle is 0.009mm / s, which is less than the preset displacement change rate of 0.01mm / s; the fiber bundle displacement range is 0.04mm, which is less than the preset fiber bundle displacement range of 0.05mm, thus confirming that the impregnation meets the standard.

[0157] The fiber preform that has been impregnated to the required standard is pulled through the curing mold at a second preset traction rate of 0.05 m / min, and then sequentially passes through a first heating zone at 80°C, a first platform zone at 90°C (lasting 10 min), a second heating zone at 120°C, a second platform zone at 130°C (lasting 15 min), and a third heating zone at 170°C to obtain a cured preform.

[0158] During the curing process, a temperature sensor is set every 80mm along the axial direction of the curing mold to monitor the temperature change inside the resin in real time. The temperature change rate of each monitoring point is calculated every 10s. The temperature change rate of each monitoring point is ≤2℃ / min, and there is no need to adjust the duration of the platform area.

[0159] After demolding, the cured molded body is placed horizontally on a precision platform. A laser displacement sensor is set every 100mm along the axial direction to measure the radial offset. The axial warpage is 0.32mm / m, which is less than the preset axial warpage of 0.5mm / m. The product dimensional accuracy is qualified, and wear-resistant and flame-retardant glass fiber pultruded idler tube is obtained.

[0160] After testing, the product prepared in Example 2... The 152×8×200mm idler roller tube has a measured mass ratio of glass fiber to matrix resin of 59.8:40.2, with a resin mass fraction of approximately 40%. A combustion test was conducted according to GB / T 2406-2009, showing a visible flame duration of 0 seconds and an average afterflame duration of 31 seconds. A pressure test was conducted according to GB / T 5350-2008, demonstrating that it can withstand a force of 7950N without damage. When the tube is compressed by 6mm, no surface cracks appear, and the diameter deformation is ≤0.6mm. The idler roller tube weighs 1.68kg, a 70.2% reduction compared to a steel idler roller tube of the same specifications (5.64kg). The product exhibits excellent flame retardant properties and load-bearing capacity.

[0161] Example 3

[0162] Using 2400Tex E-grade glass fiber roving, and according to the layup thickness design requirements, the number of layup combinations N=4 (0° longitudinal layer and 45° spiral layer), with a total layup thickness of 8mm. The glass fiber roving is symmetrically arranged on each spindle of the braiding machine, and each spindle is driven at a preset braiding speed. The glass fiber roving is wound layer by layer onto the surface of the mandrel, alternating between the 0° longitudinal layer and the 45° spiral layer from the inside out, to obtain a fiber preform.

[0163] During the weaving process, an online laser contour scanning device is used to continuously scan along the axial direction of the fiber preform at a scanning speed of 15 mm / s. Cross-sectional contour data is recorded at 1.5 mm intervals. Image processing algorithms are used to identify fiber interlacing points on each cross-sectional contour, and the micro-gap ratio of these interlacing points is calculated. Measurements show that the micro-gap ratio is 2.4%, which is greater than the first preset interlacing point micro-gap ratio of 1% and less than the second preset interlacing point micro-gap ratio of 5%, indicating that the fiber preform is qualified.

[0164] The qualified fiber preform is drawn into the curing mold at a first preset traction rate of 0.05 m / min. Upon entering the curing mold, bisphenol A epoxy resin (containing 15% triethyl phosphate flame retardant and 5% nano-alumina wear-resistant filler by weight of resin) is injected into the curing mold at a preset injection pressure of 0.3 MPa. By adjusting the flow rate of the resin metering pump, the final mass ratio of glass fiber to matrix resin is controlled to be 80:20.

[0165] During resin injection, a preset axial traction force of 3N is applied to each fiber bundle, and a set of laser displacement sensors is installed between the braiding machine outlet and the curing mold inlet to monitor the axial displacement of each fiber bundle in real time. The average displacement change rate of each fiber bundle is 0.007mm / s, which is less than the preset displacement change rate of 0.01mm / s; the fiber bundle displacement range is 0.03mm, which is less than the preset fiber bundle displacement range of 0.05mm, thus confirming that the impregnation meets the standard.

[0166] The fiber preform that has been impregnated to the required standard is pulled through the curing mold at a second preset traction rate of 0.05 m / min, and then sequentially passes through a first heating zone at 80°C, a first platform zone at 90°C (lasting 10 min), a second heating zone at 120°C, a second platform zone at 130°C (lasting 15 min), and a third heating zone at 170°C to obtain a cured preform.

[0167] During the curing process, a temperature sensor is set every 80mm along the axial direction of the curing mold to monitor the temperature change inside the resin in real time. The temperature change rate of each monitoring point is calculated every 10s. The temperature change rate of each monitoring point is ≤2℃ / min, and there is no need to adjust the duration of the platform area.

[0168] After demolding, the cured molded body is placed horizontally on a precision platform. A laser displacement sensor is set every 100mm along the axial direction to measure the radial offset. The axial warpage is 0.28mm / m, which is less than the preset axial warpage of 0.5mm / m. The product dimensional accuracy is qualified, and wear-resistant and flame-retardant glass fiber pultruded idler tube is obtained.

[0169] After testing, the product prepared in Example 3... The 152×8×200mm idler roller tube has a measured mass ratio of glass fiber to matrix resin of 80.2:19.8, with a resin mass fraction of approximately 20%. A combustion test was conducted according to GB / T 2406-2009, showing a visible flame duration of 0 seconds and an average afterflame duration of 22 seconds. A pressure test was conducted according to GB / T 5350-2008, demonstrating that it can withstand a force of 8450N without damage. When the tube is compressed by 6mm, no surface cracks appear, and the diameter deformation is ≤0.4mm. The idler roller tube weighs 1.41kg, a 75.0% reduction compared to a steel idler roller tube of the same specifications (5.64kg). The product exhibits superior load-bearing capacity and lightweight design, along with excellent flame-retardant properties.

[0170] Comparative Example 1

[0171] The idler roller tube was prepared using a traditional pre-impregnation process. First, the glass fiber was impregnated with resin and then woven and wound. A continuous heating curing method was used, with no plateau area. The other conditions were the same as in Example 1.

[0172] Comparative Example 2

[0173] The same preparation method as in Example 1 was used, but the interlacing point micro-gap rate detection and tension adjustment were not performed during the weaving process, and the other conditions were the same as in Example 1.

[0174] In this embodiment of the invention, the test results show that: the visible flame duration of the idler tube prepared in Comparative Example 1 was 5s in the combustion test, and the average afterflame duration was 45s, indicating that the flame retardant performance was significantly lower than that of Example 1; in the pressure test, microcracks appeared on the surface of the tube at 5500N, indicating that the load-bearing capacity was lower than that of Example 1; the axial warpage was 0.8mm / m, indicating that the dimensional accuracy was lower than that of Example 1.

[0175] In this embodiment of the invention, the test results show that: the visible flame duration of the idler tube prepared in Comparative Example 2 was 2s in the combustion test, and the average afterflame duration was 38s, indicating that its flame retardant performance was lower than that of Example 1; in the pressure test, microcracks appeared on the surface of the tube at 6800N, indicating that its load-bearing capacity was lower than that of Example 1; the axial warpage was 0.6mm / m, indicating that its dimensional accuracy was lower than that of Example 1.

[0176] In this embodiment of the invention, a comparison between Example 1 and Comparative Examples 1 and 2 shows that the visible flame duration of Example 1 is 0s and the average afterflame duration is 27s, which is much better than Comparative Examples 1 and 2. This indicates that the dry weaving and interlacing point micro-gap ratio detection ensured the layer density, and the gradient curing of the platform area achieved uniform curing of the resin, effectively improving the flame retardant performance of the product.

[0177] In this embodiment of the invention, Example 1 can withstand a force of 8255N without damage, which is much higher than Comparative Example 1 and Comparative Example 2. This shows that the structural stability of the fiber skeleton during the impregnation process is ensured by fiber bundle displacement monitoring and tension correction, thereby improving the mechanical properties of the product.

[0178] In this embodiment of the invention, the axial warpage of Example 1 is 0.3 mm / m, which is better than that of Comparative Example 1 and Comparative Example 2. This shows that the internal stress of curing is effectively released by gradient curing in the platform area and temperature monitoring feedback, which reduces the warpage deformation of the product. In addition, Example 1 reduces the weight by 26.84% compared with steel idler tube, which significantly reduces the running resistance and energy consumption of the conveyor.

[0179] In summary, the prepared glass fiber pultruded idler tubes have excellent flame retardant properties, load-bearing capacity, good dimensional accuracy, and significant lightweight effect, which can meet the requirements of conveyors under complex working conditions.

[0180] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a wear-resistant and flame-retardant glass fiber pultruded idler tube, characterized in that, include: Based on the glass fiber rovings mounted on each spindle of the braiding machine, each spindle is driven to wind layer by layer onto the surface of the mandrel in a preset layup sequence to obtain a fiber preform. The micro-gap ratio of the interlacing points of the fiber preform is determined based on the real-time acquired surface image to determine whether the fiber preform is qualified. In response to the fiber preform being qualified, based on the axial displacement of each fiber bundle under a preset axial traction force, the displacement change rate and displacement range of each fiber bundle are determined to determine whether the impregnation of the fiber preform is up to standard. If the impregnation of the fiber preform is not up to standard, the weaving tension of each spindle is corrected. In response to the impregnation of the fiber preform reaching the standard, based on the temperature data inside the cured preform that sequentially passes through the first heating zone, the first platform zone, the second heating zone, the second platform zone, and the third heating zone, and based on the temperature change rate and the axial warpage of the cured preform after demolding, the duration of the first platform zone and the second platform zone is optimized to obtain a wear-resistant and flame-retardant glass fiber pultruded idler tube. Among them, the temperature of the first heating zone is lower than the temperature of the second heating zone, and the temperature of the second heating zone is lower than the temperature of the third heating zone; The process of determining whether the fiber preform is qualified includes: The fiber preform is deemed qualified based on the interlacing point microgap ratio being greater than or equal to the first preset interlacing point microgap ratio and less than or equal to the second preset interlacing point microgap ratio. Based on the interlacing point microgap ratio being less than the first preset interlacing point microgap ratio or greater than the second preset interlacing point microgap ratio, the fiber preform is determined to be unqualified and the weaving tension of each spindle is adjusted. Wherein, the interlacing point microgap ratio is the ratio of the sum of the areas of all gap regions within the preset measurement length to the surface area corresponding to the preset measurement length; The process of determining whether the impregnation of the fiber preform meets the standard includes: Based on the fact that the displacement change rate of any fiber bundle is less than or equal to the preset displacement change rate, and the displacement range of the fiber bundle is less than or equal to the preset displacement range of the fiber bundle, it is determined that the impregnation of the fiber preform meets the standard. If the displacement change rate of any fiber bundle is greater than the preset displacement change rate, or the displacement range of the fiber bundle is greater than the preset displacement range of the fiber bundle, it is determined that the impregnation of the fiber preform is substandard and the weaving tension of each spindle is corrected. The displacement change rate is the rate of change of the axial displacement of the fiber bundle with time, which is determined by dividing the difference between the axial displacement at the current moment and the axial displacement at the previous moment by the sampling time interval. The displacement range value is the difference between the maximum and minimum axial displacements of all fiber bundles at the same moment; The process of optimizing the first platform region and the second platform region includes: Based on the fact that the rate of temperature change at any monitoring point in the first platform area or the second platform area is greater than the preset rate of temperature change, it is determined to extend the duration of the first platform area or the duration of the second platform area by an extension coefficient. The temperature change rate is the amount of temperature change per unit time, which is determined by the rate of change of temperature data at the monitoring point over time. The process of optimizing the first platform region and the second platform region further includes: Based on the fact that the axial warp is greater than the preset axial warp and the temperature change rate at any monitoring point is less than or equal to the preset temperature change rate, it is determined that the duration of the second platform area will be extended by the third extension coefficient. The axial warpage is determined based on the maximum value of the offset of each measurement point relative to the line connecting the two ends.

2. The method for preparing the wear-resistant and flame-retardant glass fiber pultruded idler tube according to claim 1, characterized in that, The process of adjusting the weaving tension at each spindle position includes: In response to the defect of the fiber preform, based on the fact that the micro-gap ratio of the interlacing point is less than the first preset micro-gap ratio of the interlacing point, it is determined to reduce the weaving tension of each spindle. The reduction in weaving tension is positively correlated with a first difference, which is determined based on a first preset interlacing point microgap ratio and an interlacing point microgap ratio.

3. The method for preparing the wear-resistant and flame-retardant glass fiber pultruded idler tube according to claim 2, characterized in that, The process of adjusting the weaving tension of each spindle also includes: Based on the fact that the interlacing point gap ratio is greater than the second preset interlacing point gap ratio, it is determined to increase the weaving tension of each spindle position; The increase in the weaving tension is positively correlated with the second difference, which is determined based on the second preset interlacing point microgap ratio and the interlacing point microgap ratio.

4. The method for preparing the wear-resistant and flame-retardant glass fiber pultruded idler tube according to claim 1, characterized in that, The process of correcting the weaving tension at each spindle position includes: Based on the fact that the displacement change rate of a single fiber bundle is greater than the preset displacement change rate, or based on the fact that the displacement range of the fiber bundle is greater than the preset displacement range of the fiber bundle and the displacement of a single fiber bundle is greater than the average displacement of all fiber bundles, the weaving tension of the corresponding spindle position is increased by an adjustment coefficient.

5. The method for preparing the wear-resistant and flame-retardant glass fiber pultruded idler tube according to claim 4, characterized in that, The process of correcting the weaving tension at each spindle position also includes: Based on the fact that the fiber bundle displacement range is greater than the preset fiber bundle displacement range, and the displacement of a single fiber bundle is less than the average displacement of all fiber bundles, it is determined that the weaving tension of the corresponding spindle position will be reduced by an adjustment coefficient.

6. A wear-resistant and flame-retardant glass fiber pultruded idler tube prepared by the method described in any one of claims 1-5, characterized in that, The idler roller tube is composed of glass fiber and matrix resin, wherein... The glass fiber is E glass fiber or S glass fiber, and the matrix resin is bisphenol A epoxy resin or vinyl ester resin. The mass ratio of the glass fiber to the matrix resin is (60-80):(40-20).

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