A method for producing a polyurethane pultrusion resin composite

Abstract

The present application relates to the technical field of polyurethane pultrusion, and particularly relates to a preparation method of polyurethane pultrusion resin composite material, which comprises the following steps: pulling glass fiber into a resin dipping tank containing polyurethane resin to perform dipping; heating the dipped glass fiber in a preforming mold to obtain a pre-solidified gel forming body; when it is determined that the preparation of the pre-solidified gel forming body does not meet preset standards according to the standard deviation of the scattering intensity of the pre-solidified gel forming body, adjusting the preparation parameters; performing pultrusion on the pre-solidified gel forming body meeting the preset standards to obtain a solidified forming body; when it is determined that the preparation of the solidified forming body does not meet preset standards according to the average corrugation amplitude, determining the adjustment strategy for the preparation of the solidified forming body which does not meet the standards according to the surface texture curvature variance; naturally cooling the solidified forming body meeting the preset standards by pulling to obtain the polyurethane resin composite material. The present application improves the preparation efficiency of the resin composite material.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of polyurethane pultrusion, and in particular to a preparation method of a polyurethane pultrusion resin composite material. BACKGROUND

[0002] The pultrusion process is a method for continuously producing composite material profiles. The method is to impregnate roving glass fiber rovings on a creel and other continuous reinforcing materials, such as polyester surface mats, with resin, then pass them through a forming die of a certain cross-sectional shape, and make them solidify and form in the die, and then continuously come out of the die, thereby forming a kind of automatic production process of pultrusion products.

[0003] Polyurethane is a polymer with urethane groups in the main chain, which is synthesized by using oligomeric polyols and isocyanate as main raw materials. Compared with traditional resins, polyurethane has better combination with reinforcing materials, and thus has excellent impact resistance, mechanical properties and weather resistance.

[0004] Glass fiber, as an inorganic fiber with excellent performance, is a brittle material with high elastic modulus, large tensile strength and small elongation at break, and has the advantage of designable mechanical properties. The product structure can be flexibly designed according to the needs to improve the overall performance of the product, and the glass fiber is widely used as a reinforcing material in resin-based composite materials.

[0005] High-performance polyurethane / glass fiber composite material is a high-strength, high-modulus and lightweight polymer composite material refined by using high-hardness polyurethane elastomer as base material and glass fiber as reinforcing material through continuous pultrusion process.

[0006] In the preparation process of high-performance polyurethane / glass fiber composite material, the temperature control in the curing stage directly affects the uniformity of the curing degree of the resin, so as to avoid surface defects or performance fluctuations caused by stress concentration.

[0007] Chinese patent application publication No. CN108943773A discloses a preparation method of a pultrusion polyurethane fiber reinforced composite material, which comprises the following steps: passing the head of continuous fibers with a mass fraction of 50-85% through a mold, the mold at least having a glue injection and impregnation zone, a preforming zone and a curing zone; injecting instantaneously synthesized polyurethane resin into the glue injection and impregnation zone of the mold in a high-pressure manner through a polyurethane resin glue injection system, so that the continuous fibers located in the glue injection and impregnation zone are completely impregnated with the high-pressure polyurethane resin; moving the head of the continuous fibers under the traction of a traction device, so that the continuous fibers impregnated with the polyurethane resin move to the preforming zone under the traction to be heated and gelled, and a preformed continuous fiber reinforced composite material is obtained; and the preformed continuous fiber reinforced composite material is pulled out to the outside of the mold after being cured and formed in the curing zone under the continuous traction force generated by the traction device.

[0008] It can be seen that the above technical solution only mentions heating the gel in the preforming area of the continuous fiber, does not consider the influence of the heating temperature of the preforming on the internal homogeneity of the continuous fiber, does not consider the correlation between the crack density and the curing temperature, affects the curing effect, and thus causes the problem of low preparation efficiency. SUMMARY

[0009] To this end, the present application provides a preparation method of a polyurethane pultrusion resin composite material to overcome the problem in the prior art that only the heating of the gel in the preforming area of the continuous fiber is mentioned, the influence of the heating temperature of the preforming on the internal homogeneity of the continuous fiber is not considered, the correlation between the crack density and the curing temperature is not considered, the curing effect is affected, and thus the problem of low preparation efficiency is caused.

[0010] To achieve the above-mentioned purpose, the present application provides a preparation method of a polyurethane pultrusion resin composite material, comprising:

[0011] The glass fiber is pulled into a resin dipping tank filled with polyurethane resin at a first preset pulling rate to perform dipping for a preset dipping time;

[0012] The dipped glass fiber is heated in a preforming mold in sequence at a first preset heating temperature, a second preset heating temperature and a third preset heating temperature at a second preset pulling rate to obtain a pre-cured gel forming body, a scattering intensity map of the pre-cured gel forming body is obtained, and a scattering intensity standard deviation of the pre-cured gel forming body is calculated, wherein the first preset heating temperature is less than the second preset heating temperature and the second preset heating temperature is less than the third preset heating temperature;

[0013] When it is determined that the preparation of the pre-cured gel forming body does not meet the preset standard according to the scattering intensity standard deviation of the pre-cured gel forming body, the preparation parameters are adjusted, wherein the preparation parameters include the preset dipping time and the second preset pulling rate;

[0014] The pre-cured gel forming body meeting the preset standard is pulled into a pultrusion mold at a third preset pulling rate, and pultrusion is performed at a fourth preset heating temperature to obtain a cured forming body, wherein the third preset heating temperature is less than the fourth preset heating temperature;

[0015] The amplitudes of several corrugations on the surface of the cured forming body are obtained, and an average corrugation amplitude is calculated;

[0016] When it is determined that the preparation of the cured forming body does not meet the preset standard according to the average corrugation amplitude on the surface of the cured forming body, an adjustment strategy for the preparation of the cured forming body not meeting the preset standard is determined according to the surface texture curvature variance of the cured forming body, wherein the adjustment strategy includes simultaneously reducing the second preset heating temperature and the third preset heating temperature and issuing a warning when it is determined that the heating of the pultrusion mold is uneven;

[0017] The solidified molding body meeting the preset standard is pulled and naturally cooled to obtain a polyurethane resin composite material.

[0018] Further, whether the preparation of the pre-solidified gel molding body meets the preset standard is determined according to a standard deviation of scattering intensity of the pre-solidified gel molding body, wherein,

[0019] If the standard deviation of scattering intensity is less than a first preset standard deviation of scattering intensity, it is determined that the preparation of the pre-solidified gel molding body meets the preset standard.

[0020] If the standard deviation of scattering intensity is greater than or equal to the first preset standard deviation of scattering intensity and less than a second preset standard deviation of scattering intensity, it is determined that the preparation of the pre-solidified gel molding body does not meet the preset standard, and the preset impregnation time is increased according to a ratio between the standard deviation of scattering intensity and the first preset standard deviation of scattering intensity.

[0021] If the standard deviation of scattering intensity is greater than or equal to the second preset standard deviation of scattering intensity, it is determined that the preparation of the pre-solidified gel molding body does not meet the preset standard, and the second preset pulling rate is decreased according to a difference between the standard deviation of scattering intensity and the second preset standard deviation of scattering intensity.

[0022] Further, the process of obtaining the standard deviation of scattering intensity comprises:

[0023] An incident light beam is emitted to the surface of the pre-solidified gel molding body, and a reflection and scattering signal is received by a matrix arranged photoelectric sensor to generate a scattering intensity distribution matrix.

[0024] The scattering intensity distribution matrix is divided into a plurality of rectangular sub-regions, and the scattering intensity values of all pixel points in each sub-region are extracted.

[0025] The arithmetic mean of the scattering intensity of all pixel points in each sub-region is calculated as the average scattering intensity of the sub-region.

[0026] The standard deviation of scattering intensity of the surface of the pre-solidified gel molding body is calculated.

[0027] Further, a plurality of time length adjustment modes are provided for the increase of the preset impregnation time, and each time length adjustment mode has a different increase amplitude of the preset impregnation time.

[0028] Further, whether the preparation of the solidified molding body meets the preset standard is determined according to a comparison result that the average corrugation amplitude of the surface of the solidified molding body is greater than or equal to a first preset corrugation amplitude and less than a second preset corrugation amplitude, and whether the preparation of the solidified molding body meets the preset standard is further determined according to a crack density of the solidified molding body.

[0029] Further, according to the comparison result of the average corrugation amplitude of the surface of the cured forming body being greater than the second preset corrugation amplitude, it is determined that the preparation of the cured forming body does not meet the preset standard, and an adjustment strategy for the preparation of the cured forming body not meeting the preset standard is determined according to the surface texture curvature variance of the cured forming body.

[0030] Further, the process of obtaining the average corrugation amplitude of the surface of the cured forming body comprises:

[0031] acquiring continuous surface profile point cloud data of the cured forming body by a laser scanner;

[0032] extracting the vertical distance between adjacent peaks and valleys in the profile data as a single corrugation amplitude value;

[0033] statistically calculating the arithmetic mean of all single corrugation amplitude values, denoted as the average corrugation amplitude.

[0034] Further, when the preparation of the cured forming body is determined not to meet the preset standard according to the comparison result of the crack density of the cured forming body being greater than the preset crack density, the fourth preset heating temperature is reduced by the difference between the crack density and the preset crack density; the crack density is the number of cracks per unit area on the surface of the cured forming body.

[0035] Further, the reduction range of the fourth preset heating temperature is positively correlated with the crack density difference, wherein the crack density difference is the difference between the crack density and the preset crack density.

[0036] Further, according to the surface texture curvature variance of the cured forming body, an adjustment strategy for the preparation of the cured forming body not meeting the preset standard is determined, wherein,

[0037] if the surface texture curvature variance is less than the preset surface texture curvature variance, the second preset heating temperature and the third preset heating temperature are simultaneously reduced according to the ratio of the preset surface texture curvature variance to the surface texture curvature variance;

[0038] if the surface texture curvature variance is greater than or equal to the preset surface texture curvature variance, it is determined that the heating of the pultrusion die is uneven and a warning is issued;

[0039] The surface texture curvature variance is the variance of the curvature of a plurality of detected regions of the surface profile of the cured forming body.

[0040] Compared with the prior art, the present application has the beneficial effects that the present application quantitatively evaluates the resin and fiber infiltration homogeneity based on the standard deviation of the scattering intensity of the pre-solidified gel in real time, verifies the surface smoothness of the pre-solidified gel forming body and dynamically controls the impregnation time and pulling rate; the surface wave amplitude is used to preliminarily screen the surface flatness of the cured forming body prepared, and the crack density of the cured forming body is introduced for secondary determination; the regular net-like texture caused by over-curing and the disordered texture caused by mold thermal unevenness are accurately distinguished by combining the surface texture curvature variance, and the synchronous cooling or equipment warning strategy is triggered accordingly, thereby improving the preparation efficiency of the resin composite material.

[0041] Further, the present application compares the scattering intensity standard deviation with the first and second preset scattering intensity standard deviations, respectively, uses the scattering intensity standard deviation as the core index, replaces the traditional qualitative judgment based on experience, makes the impregnation uniformity of the pre-solidified gel forming body and the pre-solidification state accurately quantifiable, and when the comparison result deviates slightly, the preparation is corrected by optimizing the impregnation parameters, and when the comparison result deviates seriously, the preparation effect is improved by adjusting the pulling parameters, thereby avoiding over-adjustment or under-adjustment.

[0042] Further, the present application sets three-stage heating temperatures in the preforming mold, and the core purpose is to control the temperature gradient, and the gradual increase of the temperature can adapt the resin to penetrate from low viscosity to surface layer preliminary solidification, so that the resin fully penetrates the fiber gap while realizing the surface layer pre-solidification, which not only ensures that the resin fully infiltrates the fiber gap at a lower temperature stage, avoids the penetration hindered by the premature gelation of the resin caused by the sudden rise of the temperature, ensures the structural stability of the pre-solidified gel forming body and reduces the interfacial adhesion with the pultrusion mold, thereby improving the smoothness of the subsequent pultrusion process.

[0043] Further, the present application receives the reflected scattering signal by the matrix-type photoelectric sensor and generates a distribution matrix, which can cover the surface area of the pre-solidified gel forming body, avoid the one-sidedness of local single-point detection, and ensure that the collected scattering intensity data can reflect the overall surface state, thereby improving the reliability of the detection index.

[0044] Further, the present application makes secondary determination by the crack density when the average wave amplitude is in the qualified interval, which not only ensures that the surface morphology meets the standard, but also screens the hidden crack defects, avoids the products with qualified surface but structural hidden dangers flowing into the subsequent links, and improves the product quality; for the case that the average wave amplitude exceeds the standard, the surface texture curvature variance is introduced to distinguish the defect causes, realize accurate tracing, make the adjustment strategy solve the problems of improper pre-solidification parameters or mold abnormalities, and avoid blind adjustment, thereby improving the detection accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1Flow chart of the preparation method of the polyurethane pultrusion resin composite material in the embodiment of the present application;

[0046] Figure 2 Flow chart of determining whether the preparation of the pre-cured gel forming body meets the preset standard in the embodiment of the present application;

[0047] Figure 3 Flow chart of determining whether the preparation of the cured forming body meets the preset standard according to the average corrugation amplitude of the surface of the cured forming body in the embodiment of the present application;

[0048] Figure 4 Flow chart of determining the adjustment strategy when the preparation of the cured forming body does not meet the preset standard in the embodiment of the present application. DETAILED DESCRIPTION

[0049] In order to make the objects and advantages of the present application clearer, the present application will be further described below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the protection scope of the present application.

[0050] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and not to limit the protection scope of the present application.

[0051] It should be pointed out that the data in the present embodiment are obtained by comprehensive analysis and evaluation of the historical detection data and the corresponding historical detection results of the present application in the past three months before the present detection. Those skilled in the art can understand that the determination method of the present application for a single parameter can be to select the value with the highest proportion as the preset standard parameter according to the data distribution, to use weighted summation to obtain the value as the preset standard parameter, to substitute each historical data into a specific formula and to obtain the value as the preset standard parameter using the formula, or other selection methods, as long as the present application can clearly define different specific situations in the single determination process through the obtained value.

[0052] Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 , which are respectively flow chart of the preparation method of the polyurethane pultrusion resin composite material in the embodiment of the present application; flow chart of determining whether the preparation of the pre-cured gel forming body meets the preset standard in the embodiment of the present application; flow chart of determining whether the preparation of the cured forming body meets the preset standard according to the average corrugation amplitude of the surface of the cured forming body in the embodiment of the present application; and flow chart of determining the adjustment strategy when the preparation of the cured forming body does not meet the preset standard in the embodiment of the present application.

[0053] The embodiment of the present application provides a preparation method of a polyurethane pultrusion resin composite material, comprising the following steps:

[0054] In step S1, glass fibers are pulled into a resin dipping tank filled with polyurethane resin at a first preset pulling speed of 1.5 m / min for a preset dipping duration of 30 s;

[0055] In step S2, the dipped glass fibers are sequentially heated at a first preset heating temperature of 90 DEG C, a second preset heating temperature of 120 DEG C and a third preset heating temperature of 150 DEG C in a preforming mold at a second preset pulling speed of 0.9 m / min, so that a pre-cured gel forming body is obtained, a scattering intensity diagram of the pre-cured gel forming body is obtained, and a scattering intensity standard deviation of the pre-cured gel forming body is obtained, wherein the first preset heating temperature is less than the second preset heating temperature, and the second preset heating temperature is less than the third preset heating temperature;

[0056] In step S3, when the preparation of the pre-cured gel forming body does not meet the preset standard according to the scattering intensity standard deviation of the pre-cured gel forming body, the preparation parameters are adjusted, wherein the preparation parameters include the preset dipping duration and the second preset pulling speed;

[0057] In step S4, the pre-cured gel forming body meeting the preset standard is pulled into a pultrusion mold at a third preset pulling speed of 2.0 m / min, and is pulled at a fourth preset heating temperature of 180 DEG C, so that a cured forming body is obtained, wherein the third preset heating temperature is less than the fourth preset heating temperature;

[0058] In step S5, a plurality of corrugation amplitudes of the surface of the cured forming body are obtained, and an average corrugation amplitude is obtained;

[0059] In step S6, when the preparation of the cured forming body does not meet the preset standard according to the average corrugation amplitude of the surface of the cured forming body, an adjustment strategy for the preparation of the cured forming body not meeting the preset standard is determined according to the surface texture curvature variance of the cured forming body, wherein the adjustment strategy includes simultaneously reducing the second preset heating temperature and the third preset heating temperature, and issuing a warning when it is determined that the heating of the pultrusion mold is uneven;

[0060] In step S7, the cured forming body meeting the preset standard is pulled and naturally cooled, is pulled into a room temperature environment, is placed and cooled for 30 min, and a polyurethane resin composite material is obtained.

[0061] It should be noted that the data in the present embodiment are all obtained through preliminary experiments before the present detection by the method of the present application, and each preset value can be adjusted according to the specific use, as long as the method of the present application can clearly define different specific conditions in the single item judgment process through the obtained values. The preset values set in the present embodiment are all obtained according to preliminary experiments, and each correction coefficient is also selected through experimental verification.

[0062] Specifically, the value range of the first preset heating temperature is (80℃, 100℃), the value range of the second preset heating temperature is (110℃, 130℃), and the value range of the third preset heating temperature is (140℃, 160℃). Preferably, the first preset heating temperature is selected as 90℃, the second preset heating temperature is selected as 120℃, and the third preset heating temperature is selected as 150℃.

[0063] Specifically, the cavity section shape of the preform mold is geometrically similar to the final product, and the cross-sectional area is 105%-120% of the cross-sectional area of the pultrusion mold cavity.

[0064] Specifically, after impregnation, the polyurethane resin in the preform mold has begun to crosslink and form a preliminary gel network through three stages of heating. This gel network gives the pre-solidified gel forming body the ability to maintain its shape and structural stability, allowing it to maintain its preliminary shape under the action of traction force without losing its shape due to its own gravity or flow.

[0065] Specifically, the preparation of the pre-solidified gel forming body is determined according to the standard deviation of the scattering intensity of the pre-solidified gel forming body, wherein,

[0066] If the standard deviation of the scattering intensity is less than the first preset standard deviation of the scattering intensity 1.8, it is determined that the preparation of the pre-solidified gel forming body meets the preset standard;

[0067] If the standard deviation of the scattering intensity is greater than or equal to the first preset standard deviation of the scattering intensity and less than the second preset standard deviation of the scattering intensity 4.5, it is determined that the preparation of the pre-solidified gel forming body does not meet the preset standard, and the preset impregnation time is increased according to the ratio between the standard deviation of the scattering intensity and the first preset standard deviation of the scattering intensity;

[0068] If the standard deviation of the scattering intensity is greater than or equal to the second preset standard deviation of the scattering intensity, it is determined that the preparation of the pre-solidified gel forming body does not meet the preset standard, and the second preset traction rate is decreased according to the difference between the standard deviation of the scattering intensity and the second preset standard deviation of the scattering intensity.

[0069] Specifically, based on the judgment method of the standard deviation of the scattering intensity of the pre-cured gel forming body, the spatial distribution heterogeneity of the optical scattering signal (quantified by the standard deviation) is used to evaluate the surface preparation quality of the material. The standard deviation of the scattering intensity is less than the first preset standard deviation of the scattering intensity, which means that the scattering intensity of each sub-region is very close to the average value. This indicates that the surface and near-surface structure of the forming body is highly uniform within the entire measurement area. It is a good surface smoothness, sufficient resin infiltration, uniform fiber distribution and consistent initial curing state. The standard deviation of the scattering intensity is in a medium state, which means that there is a certain fluctuation in the scattering intensity of each sub-region. This indicates that there is local heterogeneity. This heterogeneity is due to insufficient or uneven resin infiltration of the glass fiber bundle, resulting in local dry fibers, micro-bubbles or resin-rich areas, which in turn affect the surface state. By extending the impregnation time, the resin has more time to fully infiltrate and penetrate the fibers. The standard deviation of the scattering intensity is greater than the second preset standard deviation of the scattering intensity, which means that the scattering intensity of the surface of the pre-cured gel forming body is very different. This indicates that there is severe heterogeneity.

[0070] Specifically, the first preset standard deviation of the scattering intensity is selected as 1.8, and the second preset standard deviation of the scattering intensity is selected as 4.5, but the above values are not limited thereto, and those skilled in the art can adjust the above values according to actual needs.

[0071] Specifically, the process of obtaining the standard deviation of the scattering intensity includes:

[0072] The incident light beam is emitted to the surface of the pre-cured gel forming body, and the reflected scattering signal is received by the matrix arranged photoelectric sensor to generate a scattering intensity distribution matrix;

[0073] The scattering intensity distribution matrix is divided into a plurality of rectangular sub-regions, and the scattering intensity values of all pixel points in each sub-region are extracted;

[0074] The arithmetic mean of the scattering intensity of all pixel points in each sub-region is calculated as the average scattering intensity of the sub-region;

[0075] The standard deviation of the scattering intensity of the surface of the pre-cured gel forming body is calculated.

[0076] Specifically, the increase of the preset impregnation time is provided with a plurality of time adjustment modes, wherein,

[0077] If the standard deviation of the scattering intensity ratio is less than the first preset standard deviation of the scattering intensity ratio 1.25, the preset impregnation time is increased to the corresponding value using the first time adjustment coefficient 1.02;

[0078] If the scattering intensity standard deviation ratio is greater than or equal to the first preset scattering intensity standard deviation ratio and less than the second preset scattering intensity standard deviation ratio 1.75, the preset impregnation time length is increased to a corresponding value using a second time length adjustment coefficient 1.04;

[0079] If the scattering intensity standard deviation ratio is greater than or equal to the second preset scattering intensity standard deviation ratio, the preset impregnation time length is increased to a corresponding value using a third time length adjustment coefficient 1.06;

[0080] The scattering intensity standard deviation ratio is the ratio between the scattering intensity standard deviation and the first preset scattering intensity standard deviation.

[0081] Specifically, whether the preparation of the cured molding body meets the preset standard is determined according to the average waviness amplitude of the surface of the cured molding body, wherein,

[0082] If the average waviness amplitude is less than the first preset waviness amplitude 0.10 mm, it is determined that the preparation of the cured molding body meets the preset standard;

[0083] If the average waviness amplitude is greater than or equal to the first preset waviness amplitude and less than the second preset waviness amplitude 0.35 mm, it is determined that the preparation of the cured molding body meets the preset standard, and whether the preparation of the cured molding body meets the preset standard is determined again according to the crack density of the cured molding body;

[0084] If the average waviness amplitude is greater than or equal to the second preset scattering intensity standard deviation ratio, it is determined that the preparation of the cured molding body does not meet the preset standard, and the adjustment strategy for the preparation of the cured molding body that does not meet the preset standard is determined according to the surface texture curvature variance of the cured molding body.

[0085] Specifically, the first preset waviness amplitude has a value range of (0.09 mm, 0.299 mm), and the second preset waviness amplitude has a value range of (0.30 mm, 0.50 mm). Preferably, the first preset waviness amplitude is selected as 0.10 mm, and the second preset waviness amplitude is selected as 0.35 mm.

[0086] Specifically, the waviness amplitude of the surface of the cured molding body reflects the flatness of the surface thereof. A smaller waviness amplitude means that the surface is smooth and has small fluctuations, while a larger waviness amplitude indicates that the surface has obvious undulations.

[0087] Specifically, the process of obtaining the average waviness amplitude of the surface of the cured molding body comprises:

[0088] Obtaining continuous surface contour point cloud data of the cured molding body by a laser scanner;

[0089] The vertical distance between adjacent peaks and valleys in the profile data is extracted as a single-corrugation amplitude value;

[0090] The arithmetic mean of all single-corrugation amplitude values is calculated as the average corrugation amplitude.

[0091] Specifically, when the comparison result indicates that the preparation of the cured molding body does not meet the preset standard, the fourth preset heating temperature is reduced according to the difference between the crack density of the cured molding body and the preset crack density; the crack density is the number of cracks per unit area on the surface of the cured molding body. 2

[0092] Specifically, a camera is used to take a surface image of the cured molding body, and an image analysis software is used to identify and count the number of cracks per unit area.

[0093] Specifically, the preset crack density is selected as 0.3 cracks / cm 2 , but the above value is not limited thereto, and those skilled in the art can adjust the above value according to actual needs.

[0094] Specifically, the crack density is used to measure the surface quality and internal structural integrity of the material, and the presence of cracks will reduce the mechanical properties of the material, while also increasing the permeability of the material, reducing its weather resistance and corrosion resistance.

[0095] Specifically, the fourth preset heating temperature is reduced in a positive correlation with the crack density difference, wherein the positive correlation is, for example, a linear positive correlation or a nonlinear positive correlation, and the linear slope of the linear positive correlation is not specifically limited. It can be understood that the greater the crack density difference, the greater the reduction range of the fourth preset heating temperature; the crack density difference is the difference between the crack density and the preset crack density.

[0096] Specifically, the adjustment strategy for determining that the preparation of the cured molding body does not meet the preset standard is determined according to the surface texture curvature variance of the cured molding body, wherein,

[0097] If the surface texture curvature variance is less than a preset surface texture curvature variance of 0.13 mm -2 , then the second preset heating temperature and the third preset heating temperature are simultaneously reduced according to the ratio of the preset surface texture curvature variance to the surface texture curvature variance;

[0098] If the surface texture curvature variance is greater than or equal to the preset surface texture curvature variance, it is determined that the heating of the pultrusion mold is uneven and a warning is issued.

[0099] Specifically, the process of obtaining the surface texture curvature variance includes: ​

[0100] The non-contact laser scanner is used to collect three-dimensional point cloud data of the surface of the solidified molding body;

[0101] The scanning data is equally divided into a plurality of detection regions along the fiber traction direction;

[0102] For each detection region, a quadratic surface equation is fitted by the least square method, and the curvature value is calculated;

[0103] After calculating the arithmetic mean of the curvatures of all regions, the variance is calculated, which is denoted as the surface texture curvature variance.

[0104] In this embodiment, the preset surface texture curvature variance is selected as 0.13mm -2 , but the above-mentioned value is not limited thereto, and the above-mentioned value can be adjusted according to actual needs by those skilled in the art.

[0105] Specifically, when the surface texture curvature variance is lower than the preset threshold value, it indicates that there is a pre-solidification layer over-thickness defect, and the pre-solidification stage temperature that is too high will cause the polyurethane resin to be over-crosslinked, causing the surface layer to harden and thicken. The hardened surface layer loses fluidity, which hinders the resin from fully filling the mold cavity during the subsequent pultrusion process, forming a large range of uniform wave topography. Such waves exhibit long-period, low-gradient continuous undulations, resulting in a gentle change in surface curvature and a decrease in curvature variance.

[0106] When the surface texture curvature variance reaches or exceeds the preset threshold value, it indicates that there is a mold heating system failure. The pultrusion mold temperature control failure causes the local temperature difference to exceed the standard, causing the resin curing rate to suddenly change. The non-uniform curing process causes the shrinkage stress distribution to be unbalanced, forming local sharp peak and valley defects. Such defects exhibit short-wavelength, high-gradient sudden topography, resulting in a sharp fluctuation in surface curvature and an increase in curvature variance.

[0107] Thus, the technical solutions of the present application have been described in connection with the preferred embodiments shown in the drawings, but those skilled in the art will readily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after such changes or replacements will all fall within the protection scope of the present application.

[0108] The above description is only the preferred embodiments of the present application and is not intended to limit the present application; for those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing a polyurethane pultrusion resin composite material, characterized by, The method comprises the following steps: glass fibers are drawn into a resin tank filled with polyurethane resin at a first preset drawing speed for a preset impregnation time; the impregnated glass fibers are heated in a preforming mold at a second preset drawing speed, in sequence, at a first preset heating temperature, a second preset heating temperature, and a third preset heating temperature, to obtain a pre-solidified gel forming body, obtain a scattering intensity map of the pre-solidified gel forming body, and calculate the scattering intensity standard deviation of the pre-solidified gel forming body, wherein the first preset heating temperature is less than the second preset heating temperature, and the second preset heating temperature is less than the third preset heating temperature; if the preparation of the pre-solidified gel forming body does not meet the preset standard according to the scattering intensity standard deviation of the pre-solidified gel forming body, adjust the preparation parameters, wherein the preparation parameters include the preset impregnation time and the second preset drawing speed; the pre-solidified gel forming body that meets the preset standard is drawn into a pultrusion mold at a third preset drawing speed, and is pultruded at a fourth preset heating temperature to obtain a solidified forming body, wherein the third preset heating temperature is less than the fourth preset heating temperature; obtain the surface wave amplitude of the solidified forming body, and calculate the average wave amplitude; if the preparation of the solidified forming body does not meet the preset standard according to the average wave amplitude of the surface of the solidified forming body, determine the adjustment strategy for the preparation of the solidified forming body according to the surface texture curvature variance of the solidified forming body, wherein the adjustment strategy includes simultaneously reducing the second preset heating temperature and the third preset heating temperature, and issuing a warning if it is determined that the heating of the pultrusion mold is uneven; the solidified forming body that meets the preset standard is drawn and naturally cooled to obtain a polyurethane resin composite material.

2. The method of producing a polyurethane pultrusion resin composite material according to claim 1, characterized by, determine whether the preparation of the pre-solidified gel forming body meets the preset standard according to the scattering intensity standard deviation of the pre-solidified gel forming body, wherein if the scattering intensity standard deviation is less than a first preset scattering intensity standard deviation, it is determined that the preparation of the pre-solidified gel forming body meets the preset standard; if the scattering intensity standard deviation is greater than or equal to the first preset scattering intensity standard deviation and less than a second preset scattering intensity standard deviation, it is determined that the preparation of the pre-solidified gel forming body does not meet the preset standard, and the preset impregnation time is increased according to the ratio between the scattering intensity standard deviation and the first preset scattering intensity standard deviation; if the scattering intensity standard deviation is greater than or equal to the second preset scattering intensity standard deviation, it is determined that the preparation of the pre-solidified gel forming body does not meet the preset standard, and the second preset drawing speed is reduced according to the difference between the scattering intensity standard deviation and the second preset scattering intensity standard deviation.

3. The method of producing a polyurethane pultrusion resin composite material according to claim 2, characterized by, The process of obtaining the scattering intensity standard deviation comprises the following steps: emit an incident light beam to the surface of the pre-solidified gel forming body, receive the reflected scattering signal through a matrix arranged photoelectric sensor, and generate a scattering intensity distribution matrix; divide the scattering intensity distribution matrix into several rectangular sub-regions, and extract the scattering intensity values of all pixel points in each sub-region; calculate the arithmetic mean of the scattering intensity of all pixel points in each sub-region as the average scattering intensity of the sub-region; The standard deviation of scattering intensity of the surface of the pre-cured gel forming body is calculated.

4. The method of producing a polyurethane pultrusion resin composite material according to claim 3, characterized by, The preset impregnation time length is increased by several time length adjustment modes, and each time length adjustment mode has different increase amplitude of the preset impregnation time length.

5. The method of producing a polyurethane pultrusion resin composite material according to claim 4, characterized by, According to the comparison result of the average corrugation amplitude of the surface of the cured forming body being greater than or equal to the first preset corrugation amplitude and less than the second preset corrugation amplitude, it is determined that the preparation of the cured forming body meets the preset standard, and whether the preparation of the cured forming body meets the preset standard is determined again according to the crack density of the cured forming body.

6. The method of producing a polyurethane pultrusion resin composite material according to claim 5, characterized by, According to the comparison result of the average corrugation amplitude of the surface of the cured forming body being greater than the second preset corrugation amplitude, it is determined that the preparation of the cured forming body does not meet the preset standard, and the adjustment strategy for the preparation of the cured forming body not meeting the preset standard is determined according to the surface texture curvature variance of the cured forming body.

7. The method of producing a polyurethane pultrusion resin composite material according to claim 6, characterized by, The process of obtaining the average corrugation amplitude of the surface of the cured forming body comprises: obtaining continuous surface profile point cloud data of the cured forming body by a laser scanner; extracting the vertical distance between adjacent wave crests and troughs in the profile data as a single corrugation amplitude value; statistically calculating the arithmetic mean of all single corrugation amplitude values, denoted as the average corrugation amplitude.

8. The method of producing a polyurethane pultrusion resin composite material according to claim 7, characterized by, When it is determined again that the preparation of the cured forming body does not meet the preset standard according to the comparison result of the crack density of the cured forming body being greater than the preset crack density, the fourth preset heating temperature is reduced according to the difference between the crack density and the preset crack density; the crack density is the number of cracks per unit area on the surface of the cured forming body.

9. The method of producing a polyurethane pultrusion resin composite material according to claim 8, characterized by, The reduction amplitude of the fourth preset heating temperature is positively correlated with the crack density difference, wherein the crack density difference is the difference between the crack density and the preset crack density.

10. The method of producing a polyurethane pultrusion resin composite material according to claim 9, characterized by, According to the adjustment strategy for the preparation of the cured forming body not meeting the preset standard determined according to the surface texture curvature variance of the cured forming body, wherein, if the surface texture curvature variance is less than the preset surface texture curvature variance, the second preset heating temperature and the third preset heating temperature are reduced synchronously according to the ratio of the preset surface texture curvature variance to the surface texture curvature variance; if the surface texture curvature variance is greater than or equal to the preset surface texture curvature variance, it is determined that the heating of the pultrusion die is uneven and a warning is issued; the surface texture curvature variance is the variance of the curvature of several detected regions of the surface profile of the cured forming body.

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