Method for testing environmental adaptability of flame-retardant polypropylene before and after molding

Abstract

The application relates to a kind of flame-retardant polypropylene environmental adaptability detection methods of front and rear double-path contrast, and relates to material detection technical field, the method comprises: from the same production batch of flame-retardant polypropylene material obtains first particle group, second particle group and reference particle group;Make first particle group with particle form experience preset environmental cycle and state adjustment and then injection molding is formed into first test sample;Second particle group is injection molded into second test sample and then experiences same environmental cycle;Reference particle group does not experience environmental cycle and is directly formed into reference test sample;Three kinds of test samples are detected under preset detection condition, with the performance difference of first test sample, second test sample and reference test sample respectively as storage processing influence quantity and product service influence quantity, and the relative size of the absolute value of the two is determined to determine environmental action sensitive type.The application has the advantages that the storage and transportation influence before molding and the service influence after molding are separated and attributed.

Description

Technical Field

[0001] This application relates to the field of materials testing technology, and in particular to a method for testing the environmental adaptability of flame-retardant polypropylene by comparing two paths before and after molding. Background Technology

[0002] Flame-retardant polypropylene, after modification, is widely used in appliance housings, automotive interior parts, and electrical structural components. The raw material, in granular form, undergoes packaging, warehousing, and long-distance transportation before entering the injection molding workshop. As the supply chain extends across regions, the interval between the granules leaving the factory and being used in the machine can reach several months, during which time they experience the high humidity of the rainy season, the high temperatures inside containers, and the low temperatures of winter. During this stage, the granules undergo moisture absorption, clumping, additive migration to the surface, and initial oxidation. While the increase in moisture content can be reversed by drying, other irreversible changes do not.

[0003] After products are delivered for use, they continue to experience high temperatures, humidity, and temperature fluctuations in the service environment. Surface oxidation, additive precipitation, secondary crystallization, and internal stress relaxation will cause the product's performance to change over time. When products exhibit changes in melt flow rate, increased color difference, decreased impact strength, or fluctuations in flame retardancy, the direction of improvement depends on whether the problem lies in the raw material storage and transportation stage or the product's service stage: the former points to adjustments in storage conditions and inventory cycles, while the latter points to strengthening the formulation's anti-aging capabilities and enhancing product protection. The resources and rectification cycles required for the two differ significantly.

[0004] Existing environmental adaptability testing methods for flame-retardant polypropylene typically involve first injection molding granules into samples according to standards, then subjecting the samples to high temperature, high humidity, low temperature, or temperature and humidity cycling treatments. The tensile, impact, bending, heat distortion, or flame-retardant properties are then tested. This approach applies environmental effects solely after molding, leaving no link in the testing chain for the entire process from granules entering the factory to being installed on the machine. Testing of incoming granules only measures granule-specific indicators such as moisture content, agglomeration, and melt flow rate. However, granule indicators and product performance are separated by a complete injection molding process, making it impossible to distinguish between reversible moisture content and irreversible molecular chain changes in granule indicators. Furthermore, the performance and appearance inspection criteria at each stage of the production line are based on whether the current values ​​fall within the specification limits. The width of the specification limits must cover normal production fluctuations, thus exceeding the drift range of a single batch of material. Each of the above approaches only observes one segment of the environmental impact chain, and none of them treats whether the environmental impact is applied before or after molding as a controllable variable. As a result, the impact of the storage and transportation stage and the impact of the service stage are always superimposed on the same final performance value. When anomalies occur in the product, inferences can only be made based on the single superimposed result. Inferences depend on assumptions, and different assumptions give mutually exclusive conclusions, making it impossible to determine the division of responsibility and the direction of improvement. Summary of the Invention

[0005] To address the problem that existing testing methods do not treat whether environmental effects are applied before or after molding as a controllable variable, resulting in the superposition of the effects of the storage and transportation stage and the service stage on the same final performance value, making it impossible to separate and attribute the cause, this application provides a dual-path comparison method for testing the environmental adaptability of flame-retardant polypropylene before and after molding.

[0006] This application provides a dual-path comparison method for testing the environmental adaptability of flame-retardant polypropylene before and after molding, which adopts the following technical solution: A method for testing the environmental adaptability of flame-retardant polypropylene using a dual-path comparison before and after molding includes the following steps: S1. Obtain the first particle group, the second particle group, and the reference particle group from the same production batch of flame-retardant polypropylene material; S2. The first particle group is subjected to a preset environmental cycle in particle form, and then the state of the first particle group is adjusted according to preset adjustment conditions. Then, the first particle group is injection molded according to a preset injection molding process to obtain the first sample. S3. Perform injection molding on the second particle group according to the preset injection molding process to obtain a second sample, and subject the second sample to the preset environmental cycle; S4. Without subjecting the reference particle group to the preset environmental cycle, perform injection molding on the reference particle group according to the preset injection molding process to obtain a reference sample; S5. Perform performance tests on the first sample, the second sample, and the reference sample according to preset test conditions to obtain the performance test results of each sample on the preset test items; S6. The differences between the performance test results of the first sample, the second sample and the reference sample are respectively determined as the storage and processing influence amount and the product service influence amount; S7. Determine the environmental sensitivity type of the flame-retardant polypropylene material based on the relative magnitude of the absolute values ​​of the storage and processing impact amount and the product service impact amount.

[0007] By adopting the above technical solution, the three groups of particles are taken from the same production batch and share the preset injection molding process and preset testing conditions. The only factor that varies among the three paths is whether the environmental effect is applied before or after molding. The unit mass surface area of ​​the particle morphology is larger than that of the molded sample. The first particle group undergoes a preset environmental cycle in this morphology and is molded after state adjustment. The screw shearing and high-temperature melting during the injection molding process amplify the irreversible changes inside the particles into measurable performance differences. By referring to the combined influence of the injection molding process itself and the initial state of the raw materials on the sample, the difference between the two paths is reduced by the same baseline. Thus, the influence of the storage and transportation stage and the influence of the service stage are respectively attributed to two measurable quantities. The environmental sensitivity tendency of this batch of materials can be determined by the relative magnitude of their absolute values.

[0008] Optionally, S4 includes sub-steps S41-S43: S41. Divide the reference particle component into a pre-reference portion and a post-reference portion; S42. In the same molding batch as the injection molding of the second particle group, the front reference part is injection molded according to the preset injection molding process to obtain the front reference sample, and the front reference sample is placed according to the preset placement conditions until the second sample completes the preset environmental cycle. S43. Within the same molding batch as the injection molding of the first particle group, the subsequent reference part is injection molded according to the preset injection molding process to obtain the subsequent reference sample; The reference sample includes the front reference sample and the back reference sample. In step S6, the reference sample that differs from the first sample is the back reference sample, and the reference sample that differs from the second sample is the front reference sample.

[0009] By adopting the above technical solution, the duration of the environmental cycle makes it impossible for the molding times of the two paths to overlap physically. The reference particle group is divided into two parts and molded in the same batch as the two paths, so that the minuend and subtrahend of each difference are in the same molding batch, and the equipment status and material residue across batches no longer enter the difference.

[0010] Optionally, in S6, the difference between the performance test results of the previous reference sample and the subsequent reference sample is also determined as the cross-time drift calibration quantity, and the test items whose absolute value of the cross-time drift calibration quantity does not exceed the preset resolvable difference are determined as valid control items. The storage and processing influence quantity and the product service influence quantity are determined only on the valid control items.

[0011] By adopting the above technical solution, neither of the two reference samples underwent environmental cycling. The performance difference between the two reflects the system shift across time periods. Whether the shift exceeds the distinguishable threshold is used to screen out valid control items, so that the two influencing factors only participate in the subsequent judgment on the detection items that are comparable to the baseline.

[0012] Optionally, step S6 includes sub-steps S61-S65: S61. The preset detection items are divided into detection item groups according to the response mechanism, wherein the detection item groups include a degradation sensitive group, a crystallization and internal stress sensitive group, an additive and ratio sensitive group, and a surface appearance group. S62. For each of the effective control items, determine the sign of the storage and processing influence amount and the product service influence amount respectively, and determine the detection items with different signs and whose absolute values ​​of the storage and processing influence amount and the product service influence amount both exceed the preset distinguishable difference as mechanism separation items; S63. Divide the absolute values ​​of the storage and processing influence and the product service influence on each of the effective control items other than the mechanism separation item by the tolerance bandwidth of each of the effective control items in the acceptance specifications to obtain the storage and processing margin consumption ratio and the product service margin consumption ratio. S64. Perform intra-group weighted synthesis of the storage processing margin consumption ratio and the product service margin consumption ratio according to the test item group to obtain the storage processing group index and product service group index for each of the test item groups; S65. Perform inter-group weighted synthesis on each of the storage and processing group indices and each of the product service group indices to obtain the storage and processing sensitivity index and the product service sensitivity index.

[0013] By adopting the above technical solution, grouping according to response mechanism makes the change direction of each detection item in the group consistent, and detection items with different signs are extracted separately and do not participate in the synthesis. Normalization with tolerance bandwidth as the denominator makes the difference of different dimensions into the margin consumption ratio of the same caliber. Two-level weighted synthesis converges the item-by-item values ​​into a pair of directly comparable indices.

[0014] Optionally, S7 includes sub-steps S71-S72: S71. Divide the absolute value of the difference between the storage and processing sensitivity index and the product service sensitivity index by the mean of the storage and processing sensitivity index and the product service sensitivity index to obtain the sensitivity deviation ratio; S72. Determine the environmental effect sensitivity type based on the sensitivity deviation ratio, wherein S72 includes S72a, S72b, and S72c in parallel: S72a. In response to the sensitivity deviation ratio being less than a preset relative threshold, determine the environmental effect sensitivity type as a common effect type; S72b. In response to the sensitivity deviation ratio being not less than the preset relative threshold and the storage / processing sensitivity index being greater than the product service sensitivity index, determine the environmental effect sensitivity type as a pre-molding sensitivity type; S72c. In response to the sensitivity deviation ratio being not less than the preset relative threshold and the product service sensitivity index being greater than the storage / processing sensitivity index, determine the environmental effect sensitivity type as a post-molding sensitivity type.

[0015] By adopting the above technical solution, since the two indices are continuous quantities, there must be an interval where the values ​​are close but indistinguishable. This interval is delineated by comparing the deviation ratio with the relative threshold and classified into the co-action type, so that the measurement dispersion is no longer read as a deterministic sensitive directional conclusion.

[0016] Optionally, in S7, in response to the absolute value of the storage and processing influence being greater than the absolute value of the product service influence, the environmental effect sensitivity type is determined to be pre-molding sensitive; in response to the absolute value of the product service influence being greater than the absolute value of the storage and processing influence, the environmental effect sensitivity type is determined to be post-molding sensitive.

[0017] By adopting the above technical solution, two basic values ​​for sensitive types and their judgment conditions are given, so that the judgment results directly correspond to the two improvement directions of warehouse-side governance and product-side governance.

[0018] Optionally, the preset adjustment conditions are conditions that allow the first particle group to be placed in a standard test environment until the moisture content reaches equilibrium. The temperature and relative humidity of the standard test environment are the same as the temperature and relative humidity of the preset detection conditions, and the state adjustment is performed at a temperature not higher than that of the standard test environment throughout the process.

[0019] By adopting the above technical solution, using moisture content balance as the adjustment endpoint and unifying the adjustment environment with the testing environment, the surface condensation and internal and external temperature gradients at the time of exiting the chamber are eliminated; the upper limit of temperature prevents the heating and drying process from taking away the additives that have migrated to the particle surface.

[0020] Optionally, the preset environmental cycle includes at least one of high temperature cycle, high humidity cycle, low temperature cycle and temperature and humidity alternation cycle, and the preset environmental cycle is repeated for a preset number of cycles, and the first particle group and the second sample undergo the same number of preset cycles.

[0021] By adopting the above technical solution, the loop type and loop number of the two paths are kept consistent, so that the environmental exposure levels corresponding to the two influencing quantities are on the same scale, and the comparison of the difference does not fail due to different treatment intensities.

[0022] Optionally, the injection molding of the first particle group, the second particle group, and the reference particle group is performed on the same injection molding equipment and the same mold according to the preset injection molding process, wherein the preset injection molding process includes the temperature of each section of the barrel, the mold temperature, the injection pressure, the injection speed, the holding pressure, the holding time, and the cooling time.

[0023] By adopting the above technical solution, the consistency of molding conditions is implemented in equipment, molds and seven process parameters, so that no new differences are introduced between the three paths in the molding process, and the difference can be attributed to the timing of the application of environmental effects.

[0024] Optionally, the preset testing items include at least one of mechanical properties, rheological properties, thermal properties, flame retardant properties, and appearance. The mechanical properties include tensile properties, impact properties, and flexural properties; the rheological properties include melt flow rate; the thermal properties include heat distortion temperature; the flame retardant properties include vertical burning rating and glow wire test results; and the appearance includes color difference.

[0025] By adopting the above technical solution, the detection items cover four types of response channels: molecular chain, crystal structure, auxiliary agent system and surface state, so that the two types of environmental effects before and after molding can leave measurable traces on their respective sensitive items.

[0026] Optionally, the preset testing conditions include the same sample geometry, the same testing standards and parameters, the same pre-test conditioning, and the same testing equipment and laboratory environment.

[0027] By adopting the above technical solution, the consistency of the detection conditions is broken down into four executable levels, so that the difference between the three sets of detection data comes only from the sample itself and not from the measurement process.

[0028] Optionally, in step S1, a complete particle group is obtained. This complete particle group, in particle form, undergoes a preset environmental cycle and is then adjusted according to preset adjustment conditions. Following this, it is injection molded using a preset injection molding process to obtain a complete sample. The complete sample is then subjected to the preset environmental cycle again. A separate complete reference portion is extracted from the reference particle group. This reference portion is then injection molded within the same molding batch as the complete particle group using the preset injection molding process to obtain a complete reference sample. The complete reference sample is then placed according to preset placement conditions. The process continues until the full-process sample completes the second preset environmental cycle; the difference between the performance test results of the full-process sample and the full-process reference sample is determined as the full-process influence quantity, and the difference between the full-process influence quantity and the sum of the storage and processing influence quantity and the product service influence quantity is determined as the interaction influence quantity; in response to the absolute value of the interaction influence quantity exceeding a preset proportion of the smaller of the absolute values ​​of the storage and processing influence quantity and the product service influence quantity, an interaction dominance flag is determined to be established, and the interaction dominance flag, the sign of the interaction influence quantity, and the environmental effect sensitivity type are output together.

[0029] By adopting the above technical solution, the fourth path makes the additive nature of the two types of effects a verifiable quantity. The full-process reference sample formed in the same batch and placed at the same time ensures that the difference of this path does not have cross-batch drift. When the interaction is significant, an identifier and symbol are output to avoid spreading the interaction item to one side and pointing to the wrong treatment direction.

[0030] Optionally, in S5, a preset number of parallel samples are taken for each preset test item to perform performance testing. The combined standard deviation determined by the within-group standard deviation of the performance test results of the samples on both sides of the difference and the number of parallel samples is converted by a preset multiple to obtain the preset resolvable difference value of each preset test item.

[0031] By adopting the above technical solution, the difference can be derived from the measured dispersion on both sides of the difference and the number of parallel samples, rather than being predetermined, so that the judgment threshold of each test item matches its own measurement repeatability and the number of parallel samples taken.

[0032] Optionally, the first particle group and the second sample are sampled at the same number of preset cycles. Each sample of the first particle group is molded and tested according to the preset adjustment conditions and the preset injection molding process. Each sample of the second sample is tested to obtain curves showing the changes of the storage processing influence and the product service influence with the preset number of cycles. The longest common continuous cycle interval where the linear correlation coefficient of the two curves is not lower than the preset correlation coefficient is determined as the common linear interval. The relative magnitude relationship between the unit cycle change rate of the two curves within the common linear interval is determined as the cycle rate sensitivity type. The cycle rate sensitivity type and the environmental effect sensitivity type are output together.

[0033] By adopting the above technical solution, the rate of change is the quotient of the influence quantity with respect to the number of cycles. The difference in the initial state of the two paths at the zero number of cycles and the system offset that remains unchanged with the number of cycles are excluded when calculating the quotient, so that the comparison is not affected by the difference in the starting points of the two paths.

[0034] Optionally, in S2, the first particle component after undergoing the preset environmental cycle is divided into an unadjusted component and an adjusted component. The unadjusted component is directly injection molded according to the preset injection molding process without performing the state adjustment to obtain an unadjusted sample. The adjusted component is then molded according to the preset adjustment conditions to obtain the first sample. The difference between the performance test results of the unadjusted sample and the first sample is determined as a reversible component. In response to the reversible component exceeding a preset proportion of the storage and processing influence amount, a surface moisture absorption dominant indicator is determined to be established, and the surface moisture absorption dominant indicator and the environmental effect sensitivity type are output together.

[0035] By adopting the above technical solution, reversible surface moisture absorption and irreversible molecular chain changes are separated into two quantities. When the former accounts for too high a proportion, an indicator is given, so that the part that can be remedied by drying at the factory is not mistakenly included in the rectification requirements on the storage and transportation side.

[0036] Optionally, the reference particle composition is taken as an intra-batch reference sample at the first and last positions of each molding batch. The difference between the performance test results of the first and last intra-batch reference samples of the same molding batch is determined as the intra-batch drift amount. In response to the intra-batch drift amount exceeding the preset resolvable difference value, the molding batch is determined to be invalid and all injection molding in the molding batch is re-executed.

[0037] By adopting the above technical solution, and embedding intra-batch drift monitoring within the cross-time period reference, the drift of barrel residue and screw thermal stability within a single molding batch becomes a definite condition for rejection.

[0038] Optionally, in S2, the first particle group is spread out according to a preset material thickness and then subjected to the preset environmental cycle. After the cycle is completed, samples are taken from the upper, middle and lower layers of the preset material thickness for molding and testing. The maximum difference between the performance test results between the layers is determined as the non-uniformity of the effect. In response to the non-uniformity of the effect exceeding the preset non-uniformity threshold, the preset environmental cycle is determined to be invalid.

[0039] By adopting the above technical solution, the particles are a bulk bed, and the penetration depth of the hot and humid airflow is limited. The interlayer difference is used as the invalidity criterion, which distinguishes between the two situations where the material is not fully utilized and the material itself is not sensitive.

[0040] Optionally, in S2, the agglomeration ratio and bulk density of the first particle group are measured before the injection molding. In response to the agglomeration ratio exceeding a preset agglomeration threshold or the bulk density being lower than a preset bulk density threshold, a pre-molding failure flag is determined to be established, and the pre-molding failure flag and the environmental sensitivity type are output together.

[0041] By adopting the above technical solution, materials with severe agglomeration will produce underfill and voids during molding due to discontinuous feeding. Pre-screening provides an indication, so that molding defects are not mistakenly counted as a decline in the performance of the material itself.

[0042] Optionally, in response to the storage and processing group index of the additive and ratio sensitive group exceeding a preset multiple of the storage and processing group index of the other detection item groups, the additive migration dominance indicator is determined to be established, and the additive migration dominance indicator is output together with the environmental effect sensitivity type.

[0043] By adopting the above technical solution, the flame retardant rating is a threshold-type response, which is more sensitive to a small decrease in the content of additives than the mechanical term. The mechanism is attributed according to the prominence of this group of indices, so that the judgment result comes with an actionable direction for investigation.

[0044] Optionally, the upper limit of the preset environmental cycle temperature is taken as the lower of the crystallization melting initiation temperature of the flame-retardant polypropylene material and the decomposition initiation temperature of the contained flame-retardant system, and then lowered by a preset margin, and is not higher than the softening and bonding temperature of the flame-retardant polypropylene material determined by pre-test. In response to the preset environmental cycle temperature exceeding the upper limit of the temperature, the preset environmental cycle is determined to be an invalid test condition.

[0045] By adopting the above technical solution, the lower of the two characteristic temperatures and the softening and sticking temperature are used to define the upper limit of the accelerated test, so that mechanisms that do not occur during storage and transportation, such as surface softening and sticking and flame retardant decomposition, are not introduced, and the accelerated results can be extrapolated back to the actual storage and transportation conditions.

[0046] Optionally, the second sample, after undergoing the preset environmental cycle, is crushed and recycled into powder, and then remolded according to the preset injection molding process to obtain a second reuse sample. At the same time, the reference sample is crushed and recycled into powder, and then remolded according to the preset injection molding process to obtain a reference reuse sample. In response to the fact that the difference between the performance test results of the second reuse sample and the reference reuse sample is less than a preset proportion of the impact of product service, it is determined that the environmental effects on the second sample are concentrated on the surface and can be eliminated by remelting.

[0047] By adopting the above technical solution, a reference sample with the same recycled powder is used to offset the secondary thermal history brought about by remelting, so that the two different effects of surface oxidation and bulk degradation on the product side can be distinguished.

[0048] Optionally, in S64, the weight of each effective control item within its respective test item group is determined by normalizing the inverse of the ratio of the preset resolvable difference of each effective control item to the tolerance bandwidth of each effective control item in the acceptance specification.

[0049] By adopting the above technical solution, the weights are derived from the relative resolution of each detection item, so that items with high measurement resolution account for a larger proportion in the group index, thereby improving the robustness of the synthesized results.

[0050] Optionally, in S6, the ratio of the number of effective control items to the total number of preset detection items is determined as the effective control percentage. In response to the effective control percentage being lower than the preset percentage threshold, the baseline different source identifier is determined to be established, and the baseline different source identifier is output together with the environmental effect sensitivity type.

[0051] By adopting the above technical solution, the baseline verification of each item is upgraded to system-level gating, and an indicator is given when two references are not comparable over a large area, so that cross-path comparisons are not made under the premise that the baseline has become invalid.

[0052] Optionally, in S5, the number of parallel samples for the first sample, the second sample, the front reference sample, and the back reference sample is allocated according to the condition that the combined standard deviation of the storage processing influence amount is equal to the combined standard deviation of the product service influence amount, wherein the combined standard deviation is determined by the in-group standard deviation of the samples on both sides of the influence amount and the number of parallel samples respectively.

[0053] By adopting the above technical solution, the detection dispersion of the reference sample will simultaneously be included in two influencing quantities. The number of parallel samples is allocated equally according to the combined standard deviation, so that the distinguishable thresholds of the two influencing quantities are at the same level.

[0054] Optionally, in response to the environmental effect sensitivity type being determined to be pre-molding sensitive, the storage and processing influence amount corresponding to each of the multiple preset cycle numbers is taken, and the cycle number that makes the storage and processing influence amount reach a preset distinguishable difference is calculated. The cycle number is then converted into the allowable storage equivalent time of the flame-retardant polypropylene material according to the equivalence relationship between the preset environmental cycle and the actual storage and transportation conditions.

[0055] By adopting the above technical solution, the qualitative conclusions of the sensitive direction are extended to the quantitative boundary of the storage and transportation side, so that the judgment results can be directly used to set the inventory cycle of the batch of materials.

[0056] In summary, this application includes at least one of the following beneficial technical effects: 1. By comparing three groups of particles from the same production batch that were formed at different times but under the same other conditions, the effects of storage and transportation and the effects of service, which were originally superimposed on the same performance value, are separated into two measurable differences under the same nominal environmental exposure conditions. When product abnormalities occur, they can be attributed to the storage side or the product side according to the magnitude of the values, without having to rely on post-event experience to infer.

[0057] 2. The reference particle group is divided into two parts according to the molding time of the two paths, and the effective control items are screened out by the difference between the two parts. This ensures that the molding time separation forced by the environmental cycle time no longer enters the difference value, and the two influencing quantities are aligned on the baseline comparable test items.

[0058] 3. Group according to response mechanism, extract items with different signs, normalize with acceptance tolerance bandwidth and perform two-level weighted synthesis, and then delineate the common action area with deviation ratio and relative threshold, so that multiple detection items with different dimensions and possibly opposite directions of change can converge into a pair of comparable indices and provide an exit for the third type of attribution. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the overall process of a method for testing the environmental adaptability of flame-retardant polypropylene by comparing two paths before and after molding, according to one embodiment of this application.

[0060] Figure 2 This is a detailed flowchart of S6 in one embodiment of this application.

[0061] Figure 3 This is a detailed flowchart of S7 in one embodiment of this application.

[0062] Figure 4 This is a schematic diagram showing the changes in the storage and processing impact and the product service impact as a function of a preset number of cycles in one embodiment of this application. Detailed Implementation

[0063] The present application will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the application and are not intended to limit the scope of the application.

[0064] This application discloses a method for testing the environmental adaptability of flame-retardant polypropylene using a dual-path comparison before and after molding. The method involves taking three groups of granules from the same production batch of flame-retardant polypropylene material. One group is subjected to environmental effects in granular form, another group is subjected to the same environmental effects after molding into samples, and the third group is directly molded without environmental effects. First, samples are grouped and environmental effects are applied at different times. Then, performance tests are performed on the three types of samples under the same conditions. Finally, the performance differences between the two affected paths and the unaffected path are used as two types of attribution quantities, and their relative magnitudes are compared. This allows the effects of storage and transportation and the effects of service, which were originally superimposed on the same performance value, to be separated into two separately measurable quantities. This enables the improvement direction when product abnormalities occur to be attributed to either the storage side or the product side based on the numerical value.

[0065] The following section details the technical terminology, main process flow, specific implementation methods for each step, and optional implementation methods.

[0066] First, some technical terms involved in the embodiments of this application will be explained. Flame-retardant polypropylene material refers to modified flame-retardant polypropylene material used for appliance shells, automotive interior parts and electrical structural parts, which exists in granular form between leaving the factory and being installed.

[0067] Particle morphology refers to the physical state of a material before it has been injection molded, in the form of millimeter-sized granules. For the same mass, the surface area of ​​the particle morphology is larger than that of the molded sample, and the pores between the particles form airflow channels. Therefore, the particle morphology responds more directly to moisture and oxygen in the environment than the molded sample.

[0068] Preset environmental cycle refers to the process of repeating the treatment in an environmental test chamber according to a set combination of temperature and relative humidity and a set number of times, in order to reproduce the environmental effects that materials experience during storage and transportation in the laboratory.

[0069] Conditioning refers to the process of placing particles in a temperature and humidity controlled environment for a period of time after the environmental action has ended and before injection molding; the temperature and humidity conditions and the placement time based on this process are collectively referred to as preset conditioning conditions.

[0070] Preset injection molding process refers to a set of injection molding conditions shared by the three paths, including barrel temperature, mold temperature, injection pressure, injection speed, holding pressure, holding time, and cooling time.

[0071] Preset test items refer to a set of performance and appearance tests performed on three types of samples. The sample specifications, test standards and test parameters, pre-test treatment, equipment and laboratory environment on which these tests are based are collectively referred to as preset test conditions.

[0072] Storage and processing influence refers to the performance difference between the first sample and the reference sample, characterizing the portion of performance change that the material undergoes in its granular state before molding due to environmental influences and is transferred to the molded part after injection molding.

[0073] The service impact of a product refers to the performance difference between the second sample and the reference sample, which characterizes the performance changes of the material after molding due to environmental effects.

[0074] The environmental sensitivity type refers to the judgment conclusion given based on the relative magnitude of the two influencing factors mentioned above, which indicates whether the batch of materials is more sensitive to environmental effects before molding or after molding.

[0075] The terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not used to describe a specific order; "include," "have," etc., are intended to cover non-exclusive inclusion.

[0076] Reference Figure 1 The overall process of this method includes sampling grouping, environmental action path before molding, environmental action path after molding, reference sample preparation, performance testing under the same conditions, determination of two influencing factors and sensitivity type judgment, corresponding to steps S1 to S7. The examples of the following steps all follow the same benchmark scenario: the material under test is a flame-retardant reinforced polypropylene modified material with a vertical flammability rating of V0, the three groups of particles are taken from the same production batch, the preset environmental cycle adopts a temperature and humidity alternation form, and the preset test items include tensile strength, cantilever beam notched impact strength, melt flow rate, vertical flammability rating and color difference, a total of five items.

[0077] S1. Obtain a first particle group, a second particle group, and a reference particle group from the same production batch of flame-retardant polypropylene material.

[0078] The production process of this batch of flame-retardant polypropylene materials includes the following steps: raw material inspection, warehousing, material requisition, formulation, mixing, extrusion, granulation, process inspection, color mixing (i.e., product homogenization), final inspection, packaging and warehousing, and shipment inspection. The granulation process includes four steps: cooling, air drying, pelletizing, and screening. The color mixing process is completed in the homogenization tank.

[0079] The reason why the three sets of particles must be taken from the same production batch is that the quantity to be observed by this method is the performance difference between the three paths. Only when the three sets of particles are homogeneous in terms of formulation weighing, extrusion temperature history and granulation cooling rate can the difference be attributed to the timing of the application of environmental effects. Otherwise, the inherent fluctuations between batches will be mixed into the difference.

[0080] Sampling can be done by taking three portions sequentially from the discharge port of the homogenizing tank during the same continuous discharge, for example, taking 5 kg of each and labeling them separately; or by randomly selecting equal amounts of granules from multiple bags of the same batch of packaged granules, mixing them, and then dividing them into three equal portions. This alternative method also achieves the goal of making the initial state of the three groups of granules consistent.

[0081] S2. The first particle group is subjected to a preset environmental cycle in particle form, and then the state of the first particle group is adjusted according to the preset adjustment conditions. Then, the first particle group is injection molded according to the preset injection molding process to obtain the first sample.

[0082] This step is the main part of the pre-forming action path in this method. Its input is the first particle group obtained by sampling, and its output is the first sample that has undergone the environmental action before forming.

[0083] During storage, granules undergo moisture absorption, clumping, additive migration, or initial aging. These changes occur more fully in granular form because granules of the same mass have a larger surface area and shorter diffusion paths. The transfer of moisture and oxygen into the granule interior reaches equilibrium in a shorter time, while the wall thickness of molded parts prolongs the same process several times over. The purpose of conditioning is to return the granules to a temperature and humidity-controlled equilibrium state after leaving the environmental chamber, eliminating reversible factors such as surface condensation and internal / external temperature gradients. What remains in the granules are irreversible changes that do not recover with storage.

[0084] Injection molding serves a dual purpose in this pathway: particles with increased moisture content undergo moisture vaporization and thermal shear degradation under screw shearing and high-temperature melting, resulting in increased melt flow rate and internal streaks; additives migrate to the particle surface during storage and are lost during transport and melting, leading to fluctuations in flame retardant-related results. In the baseline scenario, the first particle group completes all preset cycles in an environmental chamber, is then removed and placed in a standard test environment until moisture content reaches equilibrium, before being molded into four types of samples: tensile, impact, combustion, and color chart.

[0085] In addition to using laboratory environmental test chambers, the environmental effects can also be applied by placing particles in actual warehouses or containers for on-site exposure for recorded durations. This alternative method achieves the same purpose of applying environmental effects in particle form.

[0086] In some embodiments, the preset environmental cycle includes at least one of high-temperature cycle, high-humidity cycle, low-temperature cycle, and temperature-humidity alternating cycle. The preset environmental cycle is repeated a preset number of times, and the first particle group and the second sample undergo the same number of preset cycles. The high-temperature cycle is generally maintained at a constant temperature of 60°C to 85°C, the high-humidity cycle is generally maintained at 40°C to 60°C with 85%RH to 95%RH, the low-temperature cycle is generally maintained at a constant temperature of -40°C to -20°C, and the temperature-humidity alternating cycle alternates between the high-temperature and high-humidity segment and the low-temperature segment. In the baseline scenario, the high-temperature segment of the temperature-humidity alternating cycle is maintained at 70°C and 90%RH for 8 hours, and the low-temperature segment is maintained at -20°C for 4 hours, with 2 hours of temperature rise and fall, for a total of 16 hours per cycle, and 20 cycles are performed in total.

[0087] The premise that the two paths undergo the same number of preset cycles is that the two influence quantities are comparable: if one side undergoes several more cycles, its influence quantity will include a component related to the exposure time rather than the morphology. At this time, the conclusion obtained by comparing the two will no longer point to the sensitive direction itself.

[0088] In addition to setting the pre-set environmental cycle conditions according to the above standard spectrum, they can also be set by inverting the equivalent temperature and humidity spectrum based on the temperature and humidity records of the actual storage and transportation of the batch of materials. This alternative method also achieves the purpose of reproducing the real storage and transportation environment.

[0089] As an optional implementation, the upper limit of the preset environmental cycling temperature is taken as the lower of the crystallization melting initiation temperature of the flame-retardant polypropylene material and the decomposition initiation temperature of the contained flame-retardant system, and then lowered by a preset margin, and is not higher than the softening and bonding temperature of the flame-retardant polypropylene material determined by pre-testing.

[0090] When the set temperature of the preset environmental cycle exceeds the upper limit of the temperature, the preset environmental cycle is determined to be an invalid test condition.

[0091] Both characteristic temperatures can be measured using conventional thermal analysis methods: the crystallization melting initiation temperature is determined by differential scanning calorimetry (DSC), typically 150°C to 165°C for homopolymer and copolymer polypropylene; the decomposition initiation temperature of the flame-retardant system is determined by thermogravimetric analysis (TGA), typically 250°C to 300°C for intumescent flame-retardant systems. The softening and adhesion temperature is determined by a pre-test, i.e., a small amount of particles are placed at a set temperature and a preset pile thickness for a preset time, and then observed to see if adhesion occurs between the particles. The highest temperature at which adhesion does not occur is taken as the softening and adhesion temperature for that grade. The preset margin is generally 10°C to 20°C.

[0092] The reason heat distortion temperature is not used as the basis for this upper limit is that heat distortion temperature characterizes the loss of rigidity of the sample under bending load, while particles do not bear external load in the environmental chamber, and there is no causal relationship between the two. Once the set temperature exceeds this upper limit, the particle surface will soften and stick together, and the flame retardant component may also decompose prematurely. These two mechanisms do not occur under actual storage and transportation conditions, and the storage equivalent derived from this becomes unfounded. Therefore, the set temperature should be lowered and the test repeated.

[0093] Optionally, in S2, the first particle group is spread out according to a preset material thickness and then subjected to a preset environmental cycle. After the cycle is completed, samples are taken from the upper, middle and lower layers of the preset material thickness for molding and testing. The maximum difference in the interlayer performance test results is determined as the non-uniformity of the effect.

[0094] When the unevenness of the applied environment exceeds the preset unevenness threshold, the current preset environment cycle is deemed invalid.

[0095] The granular packing is a loose bed. As the hot and humid airflow penetrates into the bed through the pores between the particles, its temperature and humidity decrease with depth. The thicker and denser the bed, the lower the actual exposure of the inner particles. The preset packing thickness is generally no more than 30 mm, and the preset non-uniformity threshold can be twice the standard deviation of the parallel sample group for this test item.

[0096] If the entire bag is placed in without control, the inner layer particles will not be fully utilized, and the material itself will be insensitive. In both cases, the final performance will be the same, and the test results will be indistinguishable. If the result is deemed invalid, the thickness of the material pile should be reduced or a breathable material tray should be used to repeat the cycle.

[0097] In one optional embodiment, the preset conditioning conditions are those that allow the first particle group to reach moisture content equilibrium in a standard test environment. The temperature and relative humidity of this standard test environment are the same as those of the preset testing conditions, and the entire conditioning process is performed at a temperature not exceeding that of the standard test environment. Referring to the prevailing regulations in the art for testing the performance of flame-retardant polypropylene, the density and molding shrinkage tests are conducted at a temperature of 23±2℃ and a relative humidity of 50±5%RH. Accordingly, the standard test environment is set at 23±2℃ and 50±5%RH, and the placement time is generally not less than 88 hours, or the moisture content is considered to have reached equilibrium based on a mass change of no more than 0.1% between two consecutive weighings.

[0098] By unifying the conditioning and testing environments, all three samples are in the same moisture state before testing, preventing moisture differences from being misinterpreted as material differences. The upper temperature limit addresses another type of interference: if rapid drying with increased temperature is used to remove moisture, additives that have migrated from the particle surface will be carried away or volatilized. Additive migration is precisely one of the storage-related changes that this method aims to observe, and the tested sample will be removed during pretreatment.

[0099] In other embodiments, in S2, the first particle component after undergoing a preset environmental cycle is divided into an unadjusted component and an adjusted component. The unadjusted component is not subjected to state adjustment but is directly injection molded according to a preset injection molding process to obtain an unadjusted sample.

[0100] After the conditioned portion is conditioned according to the preset conditioning conditions, it is molded to obtain the first sample.

[0101] The difference between the performance test results of the unadjusted sample and the first sample is determined as the reversible component.

[0102] When the reversible component exceeds the preset ratio of the storage and processing influence, the surface moisture absorption dominance indicator is determined to be established, and the surface moisture absorption dominance indicator and the environmental effect sensitivity type are output together. The method for determining the storage and processing influence is explained in S6 below.

[0103] The changes that occur in particles during storage are not of the same nature: the moisture adsorbed on the surface recovers with storage or drying, which is a reversible component; irreversible molecular chain breakage and net loss of additives do not recover with storage, which is also an irreversible component. However, the two exhibit similar behavior in the molded parts, both showing an increase in melt flow rate and a decrease in impact strength, which cannot be distinguished based on a single molding process.

[0104] The preset ratio is generally 30% to 50%. If the reversible component ratio is too high, the problem with the batch of material can be remedied by drying upon arrival at the factory. If it is still treated according to the storage and transportation side, it is a misjudgment. Therefore, an indication will be given and a re-inspection will be requested.

[0105] In some embodiments, the agglomeration ratio and bulk density of the first particle group are determined in S2 before injection molding.

[0106] When the agglomeration ratio exceeds the preset agglomeration threshold or the packing density is lower than the preset packing density threshold, the pre-forming failure flag is determined to be valid, and the pre-forming failure flag is output together with the environmental sensitivity type.

[0107] Granules may clump during storage. The conventional method for determining this phenomenon in the art is to visually inspect for clumps and powder impurities, and require that none be present. The clumping ratio can be determined by sieving, taking the percentage of granules that cannot pass through a sieve of a specified aperture. The preset clumping threshold is generally set at 5%. The bulk density is determined by graduated cylinder method, and the preset bulk density threshold is generally set at 90% of the normal bulk density of the grade.

[0108] Severely agglomerated material bridges in the hopper, causing discontinuous feeding and fluctuations in melt metering. This results in underfilling and internal voids in the molded parts. The measured decrease in strength and impact at this time comes from molding defects rather than the material itself. If not intercepted, this will be included in the impact of storage and processing.

[0109] Optionally, the injection molding of the first particle group, the second particle group, and the reference particle group is performed on the same injection molding equipment and the same mold according to a preset injection molding process. This preset injection molding process includes the temperature of each section of the barrel, the mold temperature, the injection pressure, the injection speed, the holding pressure, the holding time, and the cooling time. In the baseline scenario, the temperatures of each section of the barrel, from the feeding section to the nozzle, are 200℃, 215℃, 225℃, and 220℃ respectively; the mold temperature is 40℃; the injection pressure is 80MPa; the injection speed is 50mm / s; the holding pressure is 45MPa; the holding time is 8s; and the cooling time is 20s.

[0110] The same process parameter settings do not mean the same molding conditions: the wear degree of the screw, the actual temperature distribution of the barrel and the temperature control deviation of the mold temperature controller are different for different machines. Changing machines or molds will introduce performance deviations that are unrelated to environmental effects. Therefore, the molding of the three paths must be completed on the same equipment and the same mold.

[0111] S3. Perform injection molding on the second particle group according to the preset injection molding process to obtain the second sample, and subject the second sample to a preset environmental cycle.

[0112] This step is the main part of the path of action after molding. The only difference from S2 is the timing of the application of environmental action: the second particle group is directly molded without environmental treatment, and the second sample obtained after molding enters the environmental chamber to undergo the same preset environmental cycle as the first particle group.

[0113] The surface area to volume ratio of the molded part is much smaller than that of the particle pack. The diffusion path of moisture and oxygen into the interior changes from millimeter-scale particle radii to half the wall thickness of the sample. Therefore, environmental effects in the product form mainly occur on the surface, manifesting as surface oxidation, additive precipitation, and color changes. At the same time, the sample will also undergo secondary crystallization and internal stress relaxation at high temperatures, resulting in an increase in flexural modulus and heat distortion temperature, and dimensional shrinkage. This path corresponds to the service aging that the product experiences at the field after delivery. In the benchmark scenario, the second sample was produced in the same molding batch as the previous reference sample and then suspended in an environmental chamber according to standard clamping, with a spacing of not less than 20 mm between the samples. It then underwent the same 20 temperature and humidity cycles as the first particle group.

[0114] In some embodiments, the second sample, after undergoing a preset environmental cycle, is crushed and recycled into powder and then remolded according to a preset injection molding process to obtain a second reused sample.

[0115] Simultaneously, the reference sample is crushed and recycled into powder, and then remolded according to the preset injection molding process to obtain the reference reuse sample.

[0116] When the difference between the performance test results of the second reused sample and the reference reused sample is less than the preset ratio of the impact of product service, it is determined that the environmental effects on the second sample are concentrated on the surface and can be eliminated by remelting.

[0117] The process of crushing and remelting introduces an additional thermal history. Observing the second reused sample alone makes it impossible to distinguish whether the performance change comes from environmental factors or from this remelting. Therefore, a reference sample that has also undergone crushing and remelting is used as a comparison to make the additional thermal histories of the two cancel each other out.

[0118] If the damage to the product is concentrated on surface oxidation, remelting will remix the surface and bulk, significantly reducing the difference between reused samples. If bulk degradation has occurred, the broken molecular chains will not be restored by remelting, and the difference will remain. The preset ratio is generally 30%. This judgment can be used to determine whether the batch of products can be reused and whether subsequent investigation should focus on surface protection or the formulation's antioxidant system.

[0119] S4. Without subjecting the reference particle group to a preset environmental cycle, perform injection molding on the reference particle group according to the preset injection molding process to obtain a reference sample.

[0120] The reference sample is the zero point of this method. It means that it is a sample that has the same source, process, and testing conditions as the previous two paths, but has not been affected by the environment.

[0121] The purpose of setting this zero point is that the performance measured on the first and second samples includes changes caused by environmental factors, the inherent performance level of the material batch itself, the inherent effects of the injection molding process, and the systematic bias of the testing system. These three factors are common along three paths. By subtracting the reference sample and calculating the difference, the common part is eliminated, and the remaining part can be attributed to environmental factors. Without this zero point, the difference between the two samples would still contain the aforementioned common part, and the absolute difference between either side would be incomprehensible.

[0122] After sampling, the reference particle group bypassed the environmental chamber and was molded on the same equipment and mold as the other two groups according to the same process parameters. The resulting reference sample, along with the other samples, was then subjected to performance testing. The baseline could be obtained either by using the reference particle group from the same batch as this test, or by using a sample sealed at the time of manufacture from that batch of material and then re-testing it using the same process. This alternative method also achieves the goal of providing a baseline unaffected by environmental factors.

[0123] In one alternative implementation, S4 includes sub-steps S41 to S43.

[0124] S41. The reference particle group is divided into a pre-reference portion and a post-reference portion. The ratio of the two portions is generally determined according to the number of parallel samples each portion needs to handle, so that the two portions can be sent for testing independently in each test item.

[0125] S42. Within the same molding batch as the second particle group, the previous reference sample is injection molded according to a preset injection molding process to obtain a previous reference sample. The previous reference sample is then placed under preset placement conditions until the second sample completes the preset environmental cycle. The output of this sub-step is a baseline aligned with the molding time of the product's service path. The placement period ensures that this baseline and the second sample undergo natural aging for the same duration, thus eliminating post-crystallization and room temperature aging components from the difference between them.

[0126] S43. Within the same molding batch as the first particle group, perform injection molding on the subsequent reference sample according to the preset injection molding process to obtain the subsequent reference sample. The output of this sub-step is another baseline aligned with the molding time of the storage processing path. Its molding time is after the first particle group has completed environmental cycling and state conditioning, so it shares the same batch of equipment state as the first sample.

[0127] The preset environmental cycle duration ensures that the molding times of the two paths cannot physically overlap: the second sample must be molded before entering the environmental chamber, and the first particle group must complete the environmental cycle before molding, with the entire cycle and conditioning period in between. During this time, the thermal stability of the injection molding machine screw, the accumulation of residual material in the barrel, and the temperature control deviation of the mold temperature controller will all drift. If the two paths share the same reference, this drift will inevitably enter the difference on one side but not the other, thus becoming a non-common mold error.

[0128] After dividing the reference particle group into two parts and molding them in the same batch as the two paths, the subtrahend and minuend of each difference are in the same molding batch, and the drift is eliminated by common mode when calculating the difference. In the baseline scenario, the second sample and the previous reference sample are molded in the same batch on day 0. The second sample and the first particle group are simultaneously placed in the environmental chamber for 20 temperature and humidity cycles. On day 13, both are removed from the chamber at the same time, and the first particle group is then conditioned in the standard test environment for 88 hours. On day 17, the first sample and the subsequent reference sample are molded in the same batch. The previous reference sample is placed in the standard test environment from day 0 to day 13, and then undergoes pre-test conditioning together with the second sample. On day 18, all four samples are tested on the same day and on the same equipment.

[0129] In addition to using a set of reference particles divided into two parts, the baseline time-sharing arrangement can also use one set of reference particles to be molded separately in each molding batch. This alternative method also achieves the purpose of making the minuend and the subtrahend in the same batch.

[0130] As an optional implementation, reference particle composition is taken at the first and last positions of each molding batch as intra-batch reference samples, and the difference in performance test results between the first and last intra-batch reference samples of the same molding batch is determined as the intra-batch drift amount.

[0131] When the drift within a batch exceeds the preset resolvable difference, the batch is deemed invalid and all injection molding within that batch is re-executed.

[0132] There are also two types of drift within a single molding batch: in the early stage of startup, the temperature field of the barrel and the thermal steady state of the screw are not yet in equilibrium, and the actual melt temperature of the first few dies is lower; at the end of the batch, the residence time of the residual material in the barrel is extended, and the degree of thermal degradation is higher than that in the earlier stage.

[0133] The first and last sample sampling involves clamping the middle formal sample between the two ends of a single-batch molding batch. Generally, after starting the machine, the first 5 to 10 molds are discarded before taking the first sample, and the last sample is taken from the last mold before stopping the machine. This criterion forms a two-level nesting with the aforementioned cross-batch drift calibration: the former governs the internal process of a single molding, and the latter governs the process between two molding processes.

[0134] S5. Perform performance tests on the first sample, the second sample, and the reference sample according to the preset test conditions, and obtain the performance test results of each sample on the preset test items.

[0135] The input for this step is three samples that have completed their respective path processing, and the output is three columns of corresponding test values ​​for subsequent difference calculation.

[0136] Three types of samples were tested in parallel, with each item completed sequentially. The operating conditions for each item were as follows: density and molding shrinkage were measured at a temperature of 23±2℃ and a relative humidity of 50±5%RH. The former was measured using a densitometer, with standards ISO1183, GB / T1033.1, and ASTM D792, while the latter was measured using vernier calipers, with standards ISO294-4 and GB / T17037.4. Tensile strength and elongation at break were measured using an electronic universal testing machine at 50 mm / min, with standards ISO527, GB / T1040, and ASTM D638. Flexural strength and flexural modulus were measured using the same equipment at 2 mm / min, with standards ISO178, GB / T9341, and ASTM D790. Notched impact strength of cantilever beams was measured using a pendulum impact testing machine with a 2.75J pendulum, with standards ISO180, GB / T1843, and ASTM D256. Melt flow rate was measured using a melt flow rate tester at 230℃ and 2.16kg, according to ISO 1133, GB / T 3682.1 and ASTM D1238; ash content was measured using a high-temperature resistance furnace, according to ISO 3451-1 and GB / T 9345.1; heat distortion was measured using a heat distortion tester, according to ISO 75 and GB / T 1634.1; ball pressure was measured using a ball pressure testing apparatus, according to IEC 60695-10-2 and GB / T 5169.21; vertical burning was measured using a horizontal-vertical burning tester according to the test thickness, according to UL 94 and GB / T 2408; glow wire was measured using a glow wire tester according to the test thickness, according to IEC 60695-2-11, GB / T 5169.12 and GB / T 5169.13; oxygen index was measured using an oxygen index meter, according to ISO 4589 and GB / T 2406.

[0137] For materials whose flame retardancy rating is determined by needle flame test, the project set replaces vertical burning, glow wire and oxygen index with needle flame burning. Needle flame burning is determined by needle flame testing machine according to the test thickness, and the standards are IEC60695-11-5 and GB / T5169.5.

[0138] The above items can be performed according to either ISO standards or the corresponding GB / T standards. This alternative method also achieves the goal of taking data from the three types of samples under the same test procedure, but the same set of standards must always be used for the three types of samples in the same test.

[0139] In some embodiments, the preset test items include at least one of mechanical properties, rheological properties, thermal properties, flame retardancy, and appearance. The mechanical properties include tensile properties, impact properties, and flexural properties; the rheological properties include melt flow rate; the thermal properties include heat distortion temperature; the flame retardancy includes vertical burning rating and glow wire test results; and the appearance includes color difference. The dimensions of each item are different: density is expressed in g / cm³. 3 Tensile strength, flexural strength, and flexural modulus are expressed in MPa; elongation at break, ash content, molding shrinkage, and oxygen index are expressed in %; and notched impact strength of cantilever beams is expressed in kJ / m. 2 The melt flow rate is expressed in g / 10min, the ball pressure in mm, the heat distortion in °C, the vertical combustion is the graded result, the glow wire is characterized by the ignition temperature and flammability index in °C, and the color is the color difference value.

[0140] The criteria for judging appearance are as follows: color is judged by colorimeter or visual inspection, with a color difference not exceeding 1.0; black spots, white spots, and pitting are judged by visual inspection according to internal standards; long strips, continuous particles, and tails, as well as vacuum defects, are judged by visual inspection, with no more than 5 per 100g; discolored lines and agglomerated powder impurities are judged by visual inspection, and are not allowed. The above items are distributed across four response channels: molecular chain, crystal structure, additive system, and surface state. Both pre- and post-molding environmental effects can leave measurable traces on their respective sensitive channels.

[0141] Optionally, the preset testing conditions include identical sample geometry, identical testing standards and parameters, identical pre-test conditioning, and identical testing equipment and laboratory environment. Sample geometry is specified by the relevant standards, such as the shape and thickness of tensile samples, the notch type and depth of impact samples, and the test thickness of combustion samples; all three types of samples must be of the same specification. Testing parameters refer to the set values ​​for the above-mentioned items, such as rate, pendulum energy, temperature, and load. Pre-test conditioning refers to placing the three types of samples under the same temperature and humidity conditions for the same duration before testing. Equipment and laboratory environment refer to the same equipment, the same operator, and laboratory conditions of 23±2℃ and 50±5%RH. In practice, it is advisable to arrange for the three sets of samples for the same item to be completed consecutively on the same day.

[0142] Any loss of control in any of the four levels will introduce an offset between the three data columns that is unrelated to the sample itself: different sample thicknesses will change the notch sensitivity of the impact, standard switching will change the tensile rate, different placement time before testing will bring moisture differences, and cross-day and cross-machine will superimpose equipment calibration drift. Once these offsets enter the difference, they will be misread as the contribution of environmental effects.

[0143] In other embodiments, in S5, a preset number of parallel samples are taken for performance testing of each preset test item. The combined standard deviation, determined by the within-group standard deviation of the performance test results of the two samples and the number of parallel samples, is converted by a preset multiple to obtain the preset resolvable difference value for each preset test item. The preset resolvable difference value refers to the minimum amplitude required for the difference between two values ​​in the test item to be judged as a true difference rather than a measurement fluctuation. The reason for converting by the combined standard deviation rather than the within-group standard deviation of a single set of samples is that the object being judged is the difference between two sets of samples, and the dispersion of this difference is determined by the within-group standard deviation of each side and the number of parallel samples. Various standards have specified the number of parallel samples: generally 5 for tensile and bending tests, 10 for cantilever beam notched impact tests, 3 for melt flow rate tests, 5 for vertical combustion tests, and 3 for color tests; the preset multiple is generally 2 to 3, corresponding to a confidence level of approximately 95% to 99%.

[0144] The dispersion and number of parallel samples differ for each item, resulting in varying resolvable differences: In the baseline scenario, the resolvable differences for melt flow rate, tensile strength, and cantilever beam notched impact strength, calculated as described above, are 0.4 g / 10 min, 1.5 MPa, and 0.9 kJ / m, respectively. 2 Deriving the threshold from the measured dispersion, rather than pre-determining a uniform percentage, allows the judgment criterion for each item to match its own measurement repeatability and the number of parallel samples taken.

[0145] As an optional implementation, in S5, the number of parallel samples for the first sample, second sample, preceding reference sample, and following reference sample is allocated according to the condition that the combined standard deviation of the storage processing influence quantity is equal to that of the product service influence quantity. This combined standard deviation is determined by the within-group standard deviation of each sample on both sides of the influence quantity and the number of parallel samples for each. The variance of the difference between two independent measurement series is equal to the variance of each side divided by the sum of the number of parallel samples, i.e. and ,in, The combined standard deviation of the effects of storage and processing. The combined standard deviation of the factors affecting the service life of the product. , , , The standard deviations of the first sample, the second sample, the subsequent reference sample, and the previous reference sample for this test item are, in order: within-group standard deviation. , , , The number of parallel samples for each of the four is denoted as .

[0146] Taking the notched impact strength of a cantilever beam as an example, the within-group standard deviation of the four groups of samples was 1.0 kJ / m.2 If all four groups take 10 samples, then the combined standard deviation of the two influencing quantities is 0.45 kJ / m. 2 The preset resolvable difference value for this project is 0.9 kJ / m², calculated by multiplying by 2. 2 If only 5 samples can be taken from the previous reference sample due to material limitations, the combined standard deviation of the product's service life impact will rise to 0.55 kJ / m. 2 The impact of storage and processing remains at 0.45 kJ / m³. 2 The thresholds for determining the two are therefore unequal, and the side with a looser threshold is more likely to be judged as significant when comparing their magnitudes. Balancing the results under the condition of equal combined standard deviations, i.e., appropriately adding parallel samples to the reference side, can bring the thresholds of the two influencing quantities back to the same level.

[0147] S6. The differences between the performance test results of the first sample and the second sample and the reference sample are respectively determined as the storage and processing influence amount and the product service influence amount.

[0148] The input for this step consists of three columns of corresponding test values, and the output consists of two columns of corresponding differences. The difference between the first sample and the reference sample reflects the portion of the material's changes in its granular state before molding, which are then transferred to the molded part after injection molding, and is thus determined as the storage and processing influence. The difference between the second sample and the reference sample reflects the changes in the material after molding caused by environmental factors, and is thus determined as the product's service life influence.

[0149] The two differences can be attributed to different causes because they subtract the same baseline: the inherent performance level of the material, the inherent effects of the injection molding process, and the systematic bias of the testing system all coexist along three paths. These factors are eliminated simultaneously during the difference calculation, and the remaining values ​​correspond to the only variable among the three paths—the timing of the application of environmental effects. In the baseline scenario, the melt flow rate of the first sample was 2.1 g / 10 min higher than that of the reference sample, its tensile strength was 2.2 MPa lower than that of the reference sample, and its cantilever beam notched impact strength was 3.4 kJ / m lower than that of the reference sample. 2 The total afterflame time of vertical combustion was 4 seconds longer than that of the reference sample; the corresponding four parameters of the second sample were 0.3 g / 10 min higher, 0.8 MPa lower, and 1.2 kJ / m lower, respectively. 2 The color difference was significantly greater in the second sample than in the first sample, with an extension of 1 second.

[0150] In addition to taking the absolute difference mentioned above, the influence quantity can also be the ratio of the difference to the measured value of the reference sample, i.e., the relative rate of change. This alternative method can also achieve the purpose of characterizing the performance change range of each path.

[0151] Accordingly, the reference specimens include a front reference specimen and a rear reference specimen.

[0152] In S6, the reference sample that differs from the first sample is the subsequent reference sample, and the reference sample that differs from the second sample is the preceding reference sample.

[0153] This pairing relationship follows the aforementioned time-separated dual-reference sample preparation arrangement: the first sample is formed in the same batch as the subsequent reference sample, and the second sample is formed in the same batch as the previous reference sample. When the difference is calculated, the equipment state of that batch is eliminated by common mode.

[0154] If the two paths share a single reference, and this reference is from the same batch as the first sample, then the service life effect of the product will include all the drift between the two molding processes, while the storage and processing effect will not include this drift. In this case, even if the actual sensitivity of the two paths is comparable, the two differences will be systematically large and small. The sensitivity direction obtained from their size relationship will be determined by the equipment drift rather than the material properties.

[0155] In some embodiments, S6 further defines the difference between the performance test results of the preceding and following reference samples as the cross-time drift calibration value. Detection items whose absolute value of this cross-time drift calibration value does not exceed a preset resolvable difference are defined as valid control items. The storage processing influence and the product service influence are determined only for valid control items. Both reference samples are taken from the same particle group and have not undergone preset environmental cycles; their actual performance should theoretically be consistent. The difference obtained from the actual measurements is the cumulative system offset between the two molding processes and the two tests.

[0156] If the offset does not exceed the resolvable threshold for a given test item, it indicates that the two baselines can still be considered to originate from the same source for that item; once it exceeds the threshold, it means that the baselines for that item are no longer comparable, and comparing their magnitudes loses its premise. In the baseline scenario, the comparison between the cross-time drift calibration values ​​and their respective resolvable differences for the five items is as follows: melt flow rate 0.2 g / 10 min vs. 0.4 g / 10 min, tensile strength 0.6 MPa vs. 1.5 MPa, and cantilever beam notched impact strength 0.5 kJ / m. 2 For 0.9kJ / m 2 The vertical burning rating remained unchanged, and the color difference was 0.9 to 0.5. According to the four items previously identified as valid control items, the color difference item was not included in the subsequent judgment because the baseline deviation exceeded the threshold.

[0157] It should be specifically noted here that this calibration quantity cannot be used as a correction quantity to be subtracted from the two influencing quantities one by one: the measured values ​​of the first sample, the second sample, the previous reference sample, and the subsequent reference sample are denoted as follows: , , , The impact of storage and processing is The impact of product service life is Standard quantity is If the standard amount is deducted from the former, the result is: Its baseline was reversed and replaced with a previous reference sample from a different batch; the cross-batch drift increased instead of decreased. If subtracted from the latter, the result is... There is no corresponding physical quantity. Therefore, this quantity serves as a criterion for the validity of the control in this method, rather than a correction term.

[0158] As an optional implementation, in S6, the ratio of the number of effective control items to the total number of preset detection items is determined as the effective control percentage.

[0159] When the proportion of effective controls is lower than the preset proportion threshold, the baseline different source identification is determined, and the baseline different source identification is output together with the environmental effect sensitivity type.

[0160] Individual screening addresses random fluctuations in specific items. However, when multiple items simultaneously exhibit baseline shifts exceeding the threshold, the issue points to systemic causes rather than random factors. Examples include equipment maintenance or mold replacement between molding processes, stratification of raw materials within a batch, or two tests spanning the equipment calibration cycle. The preset percentage threshold is typically set between 60% and 80%.

[0161] If the identification is established, the reliability of the current judgment is insufficient to support the attribution. Resampling should be carried out twice more within a shorter time span, or two additional reference component and structural indicators should be measured to locate the source of the deviation.

[0162] In one alternative implementation, refer to Figure 2 S6 includes sub-steps S61 to S65.

[0163] S61. Based on the response mechanism, the preset test items are divided into test item groups, which include a degradation-sensitive group, a crystallization and internal stress-sensitive group, an additive and ratio-sensitive group, and a surface appearance group. Among them, melt flow rate, tensile strength, elongation at break, and impact performance change monotonically with molecular chain breakage and are classified into the degradation-sensitive group, with notched impact strength showing the most direct response to the decrease in molecular weight; flexural strength, flexural modulus, heat distortion temperature, molding shrinkage, density, and ball pressure change with crystallinity and internal stress state and are classified into the crystallization and internal stress-sensitive group; vertical burning rating, glow wire test results, oxygen index, and ash content change with additive content and ratio and are classified into the additive and ratio-sensitive group; color difference and appearance items such as precipitation and agglomeration change with surface state and are classified into the surface appearance group.

[0164] This classification runs parallel to the five-category classification based on performance: mechanical, rheological, thermal, flame retardant, and appearance. The latter determines which items to test, while the former explains the mechanism underlying the measured changes. The correspondence is as follows: among mechanical properties, tensile and impact properties belong to the degradation-sensitive group; flexural properties belong to the crystallization and internal stress-sensitive group; rheological properties belong to the degradation-sensitive group; thermal properties belong to the crystallization and internal stress-sensitive group; flame retardant properties belong to the additive and proportion-sensitive group; and appearance properties belong to the surface appearance group. The purpose of grouping is to ensure that the changes in each item within the same group under the same mechanism are consistent, providing a physical basis for subsequent synthesis.

[0165] S62. For each valid control item, determine the sign of the storage and processing influence and the product service influence. Detection items with different signs and whose absolute values ​​of both the storage and processing influence and the product service influence exceed a preset resolvable difference are identified as mechanism separation items. The input to this sub-step is two columns of differences for each item, and the output is a list of items that need to be reported separately. The remaining items continue to normalization and synthesis.

[0166] The difference in signs is not measurement noise, but rather the result of two paths triggering mechanisms in opposite directions: irreversible changes caused by moisture absorption in the particulate state lead to a decrease in flexural modulus and heat distortion temperature; secondary crystallization and internal stress relaxation in the product state at high temperatures cause the same two parameters to increase. If absolute values ​​are compared, this parameter will contribute a large difference and push the conclusion towards the side with the larger absolute value; if the signs are summed, the two cancel each other out, causing the information for this parameter to return to zero, and the method becomes ineffective for the parameter with the most significant mechanistic difference. The additional condition that both absolute values ​​exceed the threshold is to eliminate the pseudo-sign case where the signs are randomly different when both differences are within the noise range.

[0167] S63. Divide the absolute values ​​of the storage and processing influence and the product service influence for each of the valid control items (excluding the mechanism separation item) by the tolerance bandwidth of each valid control item in the acceptance specification to obtain the storage and processing margin consumption ratio and the product service margin consumption ratio. The tolerance bandwidth refers to the difference between the upper and lower limits of the item in the acceptance specification; for single-sided specifications, it is the difference between the specification value and the typical value.

[0168] For test items whose results are characterized by grades, the continuous quantities on which the grade determination is based are used for difference calculation and normalization. That is, for vertical combustion, the afterflame time and drip determination results on which the determination is based are used; for glow wire, the ignition temperature is used; and for oxygen index, the critical oxygen concentration is used. If it is necessary to use the grade itself, the grade number is assigned and the difference between the lowest grade allowed by the acceptance specification and the typical grade of the batch is used as the tolerance bandwidth.

[0169] Based on the baseline scenario, the conversions for the four valid comparison items are as follows: the acceptance specification for melt flow rate is 20±3 g / 10 min, the tolerance bandwidth is 6 g / 10 min, and the influence values ​​on both sides of 2.1 and 0.3 are converted to 0.35 and 0.05 respectively; the tolerance bandwidth for tensile strength is 10 MPa, and the influence values ​​on both sides of 2.2 and 0.8 are converted to 0.22 and 0.08 respectively; the acceptance specification for cantilever beam notched impact strength is not less than 30 kJ / m. 2 Typical value 38kJ / m 2 The tolerance bandwidth is taken as 8kJ / m 2 The influence quantities on both sides, 3.4 and 1.2, are converted to 0.43 and 0.15 respectively. The acceptance specification for the vertical combustion rating is V0, which is based on the total afterflame time of five consecutively measured samples. The upper limit of the criterion for this rating is 50s, and the typical value for this batch of materials is 20s. Based on this, the tolerance bandwidth is taken as 30s, and the influence quantities on both sides, 4s and 1s, are converted to 0.13 and 0.03 respectively. The output of this sub-step is a dimensionless quantity, which means how much of the acceptance margin of the project was consumed by this environmental action, so that the differences between the originally different dimensions fall into the same caliber and can be added and compared.

[0170] S64. Weighted composite analysis was performed within each testing item group to obtain the respective storage / processing margin consumption ratio and product service margin consumption ratio. Continuing the previous example, the degradation-sensitive group includes melt flow rate, tensile strength, and cantilever beam notched impact strength; after equal weighting, its storage / processing group index is 0.33, and its product service group index is 0.09. The additives and proportioning-sensitive group only includes vertical burning rating, with the two group indices being 0.13 and 0.03, respectively.

[0171] S65. Perform inter-group weighted synthesis on the indices of each storage and processing group and each product service group to obtain the storage and processing sensitivity index and the product service sensitivity index. Continuing the previous example, the crystallization and internal stress sensitivity group and the surface appearance group have no valid control items in the baseline scenario and do not participate in the synthesis; the two groups participating in the synthesis are weighted according to the number of valid control items they contain, with weights of 0.75 and 0.25 respectively. Based on this, the storage and processing sensitivity index is 0.28 and the product service sensitivity index is 0.08.

[0172] The stratified arrangement of the above two-level synthesis assigns different weighting criteria to each group: within a group, weighting is based on the measurement resolution of the item, while between groups, weighting is based on the coverage of items included in the mechanistic pathway. Dimensionlessness can be achieved not only by using the acceptance tolerance bandwidth as the denominator, but also by referring to the measured value of the sample on that item. This alternative method also achieves the purpose of eliminating dimensional differences; the difference lies in that the former characterizes the consumption of acceptance margin, while the latter characterizes the relative magnitude of change.

[0173] Optionally, in S64, the weight of each valid control item within its respective test item group is determined by normalizing the reciprocal of the ratio of the preset resolvable difference of each valid control item to the tolerance bandwidth of each valid control item in the acceptance specification. This ratio is denoted as the reciprocal of the relative resolution, i.e. ,in, For the first The threshold percentage for each project This is the preset distinguishable difference for the project. The tolerance bandwidth of the project; then the weight within the group. according to Normalization is determined. Continuing the previous example, the melt flow rate, tensile strength, and cantilever beam notched impact strength within the degradation-sensitive group are... The values ​​are 0.067, 0.15, and 0.113 respectively. After normalization, their weights are 0.49, 0.22, and 0.29 respectively. The weighted composite index of this storage and processing group is 0.34, which is slightly higher than the 0.33 obtained by equal weighting.

[0174] A smaller threshold percentage indicates that the smallest measurable change accounts for a smaller proportion of the acceptance margin, has higher resolution, and contains less noise in its readings, thus accounting for a larger proportion of the index within the group.

[0175] In other embodiments, when the storage and processing group index of the additive and proportion-sensitive group exceeds a preset multiple of the storage and processing group index of the other test item groups, the additive migration dominance indicator is determined to be established, and the additive migration dominance indicator is output together with the environmental effect sensitivity type. Particles undergo additive migration during storage, and the response of flame retardant related items to additive content is threshold-type: vertical flammability rating is determined according to UL94 and GB / T2408 as discrete levels such as V0, V1, and V2; glow wire is given ignition temperature and flammability index according to IEC60695-2-11, GB / T5169.12, and GB / T5169.13; oxygen index is given critical oxygen concentration according to ISO4589 and GB / T2406. A small decrease in additive content can cause the result to cross the level boundary; mechanical items show a slow response to additive content, and the same amount of additive loss often still falls within the threshold in tensile strength.

[0176] The preset multiplier is generally set to 2 to 3. When the labeling is valid, the investigation should focus on retesting the content of additives and verifying the formula, rather than attributing it to molecular chain degradation in a general way.

[0177] S7. Determine the environmental sensitivity type of flame-retardant polypropylene materials based on the relative magnitude of the absolute values ​​of the impact of storage and processing and the impact of product service.

[0178] This step is the exit point of this method; its purpose is to converge two comparable quantities into an actionable conclusion. Here, the absolute values ​​of the two influencing quantities are compared, with both performance degradation and improvement being judged based on their magnitude of change.

[0179] When the issue is determined to be pre-molding sensitive, the main problems stem from moisture absorption, clumping, additive migration, or initial aging of the particles during storage and transportation. Improvement should focus on adjusting storage and transportation conditions and inventory cycles. When the issue is determined to be post-molding sensitive, the main problems arise from aging of the product in the usage environment. Improvement should focus on enhancing the formulation's anti-aging capabilities and strengthening the product's surface protection. The resources and rectification cycles required for these two approaches differ significantly. Following the baseline scenario, the comparison between the storage and processing sensitivity index of 0.28 and the product service sensitivity index of 0.08 indicates pre-molding sensitivity. The conclusion is that this batch of material is more sensitive to the pre-molding environment, and storage and transportation conditions should be the primary target for rectification. This is supported by a list of the margin consumption ratios for each of the four valid control items.

[0180] In addition to determining the sensitivity type based on the two synthesized indices, it can also be determined and reported item by item on individual test items. This alternative method also achieves the purpose of indicating the sensitivity direction. The difference is that the former gives a global single conclusion, while the latter retains item-level resolution.

[0181] In some embodiments, refer to Figure 3 S7 includes sub-steps S71 to S72.

[0182] S71. Divide the absolute value of the difference between the storage / processing sensitivity index and the product service sensitivity index by the mean of the storage / processing sensitivity index and the product service sensitivity index to obtain the sensitivity deviation ratio. That is... ,in, The sensitivity deviation ratio, For storage and processing sensitivity index, This is the product service sensitivity index. The output of this sub-step is a dimensionless relative quantity, which serves to scale the difference between the two indices to a scale independent of their own magnitudes, allowing the same criterion to be applied to different batches with overall high or low sensitivity. Continuing the previous example, It is 0.28. The value is 0.08. Substituting it into the equation, we get... It is 1.11.

[0183] S72. Determine the type of sensitivity to environmental effects based on the sensitivity deviation ratio. S72 includes the parallel S72a, S72b and S72c.

[0184] S72a. When the sensitivity deviation ratio is less than the preset relative threshold, the environmental action sensitivity type is determined to be a combined action type. This sub-support connects to the situation where the two index values ​​are close. Its engineering meaning is that the contributions of the two types of environmental actions are roughly equal, and rectification must be carried out on both sides in parallel, rather than selectively investing in one.

[0185] S72b. When the sensitivity deviation ratio is not less than the preset relative threshold and the storage and processing sensitivity index is greater than the product service sensitivity index, the environmental effect sensitivity type is determined as the pre-molding sensitivity type.

[0186] S72c. When the sensitivity deviation ratio is not less than the preset relative threshold and the product service sensitivity index is greater than the storage and processing sensitivity index, the environmental effect sensitivity type is determined as the post-molding sensitivity type.

[0187] The preset relative threshold is calculated from the resolvable difference of each item: the resolvable difference of each valid control item is divided by the tolerance bandwidth according to S63, and then synthesized according to the weights of S64 and S65. The result is the uncertainty of the sensitivity index itself, and its ratio to the mean of the two indices is the lower limit of the relative threshold under the test conditions. Under the test conditions of this embodiment, the calculated value is approximately 0.2 to 0.3. Continuing the previous example, the relative threshold is taken as 0.25. It is 1.11 and Greater than If it falls under S72b, it is judged to be a pre-forming sensitive type; if another batch of materials 0.18 If it is 0.16, then The value is 0.12, which is less than 0.25, falling into S72a, and is judged to be a combined action type; if 0.09 If it is 0.24, then It is 0.91 and Greater than It falls into S72c and is judged to be a sensitive type after molding.

[0188] The necessity of setting a common action zone lies in the fact that the two indices are continuous quantities, and their difference must exist in a range that is small enough to be on the same order of magnitude as the measurement fluctuation; without setting this range, any tiny difference in value will be read as a deterministic sensitive direction, and this conclusion precisely guides the allocation of resources.

[0189] As an optional implementation, in S7, when the absolute value of the storage and processing influence is greater than the absolute value of the product service influence, the environmental effect sensitivity type is determined to be the pre-molding sensitivity type.

[0190] When the absolute value of the impact of product service is greater than the absolute value of the impact of storage and processing, the environmental impact sensitivity type is determined to be the post-molding sensitivity type.

[0191] This binary classification method does not involve index synthesis; it directly provides a conclusion based on the numerical values ​​of the two influencing quantities. It is suitable for situations where there are few testing items, the dimensions are consistent, or only a single item is considered for judgment.

[0192] In terms of the judgment logic, the binary classification is a degenerate form of the aforementioned ternary classification when the sensitivity deviation ratio is not less than a preset relative threshold: when the difference between the two quantities is significant enough and does not fall into the common action area, the output of the ternary classification is consistent with the binary classification, and the two constitute the coarse and fine two-level implementation of the same judgment logic.

[0193] Optionally, the first particle group and the second sample are sampled at the same number of preset cycles. The samples of the first particle group are molded and tested according to preset adjustment conditions and preset injection molding process. The samples of the second sample are tested separately to obtain the curves of the storage and processing influence and the product service influence as a function of the preset number of cycles.

[0194] The longest common continuous cycle interval where the linear correlation coefficients of the two curves are not lower than the preset correlation coefficient is defined as the common linear interval. The relative magnitude relationship between the unit cycle number change rate of the two curves within the common linear interval is defined as the cycle rate sensitivity type. This cycle rate sensitivity type is output together with the environmental effect sensitivity type.

[0195] When the same cyclic conditions are applied to a particle pack and a molded specimen, the equivalent exposure is not equal: the surface area to volume ratio of the particles is approximately... The sample is approximately The magnitude and diffusion characteristic time are respectively proportional to and ,in, The equivalent diameter of the particle. For the sample thickness, The diffusion coefficient is used. The comparison of single-point differences corresponds to the comparison of stage contributions under the same nominal exposure conditions. The actual exposure absorbed by the particle morphology under the same nominal conditions is higher than that of the molded sample. This difference is an inherent property of the material in the storage and transportation stage of the real supply chain, rather than a measurement bias that needs to be eliminated.

[0196] The rate of change is the quotient of the influencing quantity over the number of iterations. The initial state difference between the two paths at the zeroth iteration and the system offset that remains constant with the number of iterations are excluded when calculating the quotient, thus ensuring the comparison is unaffected by the difference in the starting points of the two paths. The number of points selected is generally no less than three iterations, and the preset correlation coefficient is generally 0.95. A shared linear interval must be satisfied by both curves; if each curve selects its own linear interval, the two rates of change will fall on different iteration number coordinates and will be incomparable.

[0197] Reference Figure 4Based on the baseline scenario, points were taken at the 5th, 10th, 15th, and 20th cycles. The linear correlation coefficients of the two curves between the 5th and 15th cycles were 0.98 and 0.96, respectively, both not lower than 0.95. Based on this, a common linear interval was determined. The rate of change of the storage and processing influence per unit cycle number in this interval was 0.019, while the product service influence was 0.011. The former was greater than the latter, and the cycle rate sensitivity type also pointed to the pre-molding side. Figure 4 In the figure, the horizontal axis represents the preset number of cycles, and the vertical axis represents the margin consumption ratio of the cantilever beam notch impact strength. The two curves correspond to the impact of storage and processing and the impact of product service, respectively. The ratio of the slopes of the two curves in this interval reflects the comparison of the sensitivity rates of the two paths.

[0198] In one optional implementation, in S1, a complete set of particles is obtained, and the complete set of particles undergoes a preset environmental cycle in particle form and is subjected to state adjustment according to preset adjustment conditions. Then, the sample is injection molded according to a preset injection molding process to obtain a complete sample, and the sample is subjected to a preset environmental cycle.

[0199] A reference sample is separated from the reference particle group and injection molded in the same batch as the full particle group according to the preset injection molding process to obtain a full reference sample. The full reference sample is then placed according to the preset placement conditions until the full sample completes the second preset environmental cycle.

[0200] The difference between the performance test results of the full-process sample and the full-process reference sample is determined as the full-process influence quantity, and the difference between the full-process influence quantity and the sum of the storage and processing influence quantity and the product service influence quantity is determined as the interaction influence quantity.

[0201] When the absolute value of the interaction influence exceeds the preset ratio of the smaller of the absolute values ​​of the storage and processing influence and the product service influence, the interaction dominance identifier is determined to be established, and the interaction dominance identifier, the symbol of the interaction influence, and the environmental effect sensitivity type are output together.

[0202] Right now ,in, For the amount of interaction influence, For the total impact, The impact of storage and processing The total impact on the product's service life is determined by the complete path of the particle group, which involves the sequential application of two types of environmental effects before and after molding. The resulting total impact represents the cumulative change of the material during storage, transportation, and service in the real supply chain. By adding the two impact quantities and comparing them with the total impact quantity, it is possible to verify whether the two types of effects are additive.

[0203] The fourth path takes longer than the other three, therefore its comparison must be arranged separately. Following the baseline scenario, the entire particle group and the first particle group enter the environmental chamber simultaneously. On day 17, they are molded in the same batch as the first sample, the subsequent reference sample, and the entire reference sample. The resulting entire sample then enters the second preset environmental cycle and is removed from the chamber on day 30. The entire reference sample is placed in the standard test environment from day 17 to day 30, and on day 31, it is tested on the same day and on the same equipment as the entire sample. If the difference between the previous or subsequent reference sample and the entire sample is calculated, there is a device drift of more than ten days between them. This drift, converted to melt flow rate, can reach the order of 0.03, which is on the same order of magnitude or even larger than the interaction effect to be measured. Whether the interaction dominance indicator is established will be determined by device drift rather than material properties.

[0204] The physical reason for the difference between the two is that after the particulates absorb moisture, they leave micropores and silver streaks inside the part after injection molding. These defects provide channels for oxygen diffusion during the subsequent service period, making the aging rate of the particulates higher than that of the same part that has not been affected by storage and transportation. At this time, the two types of effects amplify each other, and the interaction effect is positive. Conversely, if the initial oxidation of the particulates has consumed some unstable chain segments and reduced the subsequent oxidation rate, the two types of effects cancel each other out, and the interaction effect is negative.

[0205] The preset ratio is generally set at 20% to 30%. Following the baseline scenario, if the total impact after conversion is 0.37, the sum of the two impacts is 0.36, and the interaction impact is 0.01, which does not exceed 20% of the smaller one (0.08), i.e., 0.016, then additivity is valid, and the sensitive direction conclusion is output as usual. If the total impact is 0.42 and the interaction impact is 0.06, exceeding this threshold, then the interaction-dominant indicator is valid, and the symbol is positive. In this case, the sum of the two impacts does not equal the actual impact the material experiences in the real supply chain. The interaction item will be silently spread to one side, and the governance direction derived from its magnitude may be opposite to the real root cause. Therefore, in this case, the sensitive tendency conclusion is suppressed, and the interaction symbol is changed to prompt a two-sided joint investigation.

[0206] In other embodiments, when the environmental sensitivity type is determined to be pre-molding sensitive, the storage and processing impact value corresponding to multiple preset cycle numbers is taken, and the number of cycles required for the storage and processing impact value to reach a preset resolvable difference is calculated. Based on the equivalence between the preset environmental cycles and actual storage and transportation conditions, this number of cycles is converted into the allowable storage equivalent time for the flame-retardant polypropylene material. The inverse calculation process involves finding the intersection point between the relationship curve of the storage and processing impact value versus the preset cycle number and the horizontal line corresponding to the resolvable difference. The abscissa of the intersection point is the number of cycles required for the batch of material to begin exhibiting resolvable performance changes under the preset environmental cycle conditions. Continuing with the baseline scenario, the storage and processing impact value of the impact item increases approximately linearly with the number of cycles, reaching the resolvable difference value of 0.9 kJ / m² at the 6th cycle.2 The critical number of iterations is 6.

[0207] The approach to establishing equivalence is based on aligning cumulative exposure. This involves converting the duration and intensity of each temperature and humidity segment in a pre-defined environmental cycle into a cumulative exposure equivalent. This equivalent is then compared to the cumulative exposure equivalent corresponding to the temperature and humidity records of the actual storage and transportation links for that batch of materials. This yields the actual storage and transportation duration for a single cycle, and the critical cycle number is then converted into an allowable storage equivalent duration. This equivalence varies depending on the material grade and transportation link, and its calibration method and conversion factor can be pre-set based on the actual storage and transportation temperature and humidity records for that batch of materials. The resulting allowable storage equivalent duration can be directly used to set the inventory cycle and turnover strategy for that batch of materials.

[0208] The same or similar parts in the various embodiments of this application may be referred to each other; the technical features of each embodiment may be combined to form new embodiments when there is no conflict.

[0209] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for testing the environmental adaptability of flame-retardant polypropylene using a dual-path comparison before and after molding, characterized in that, Includes the following steps: S1. Obtain the first particle group, the second particle group, and the reference particle group from the same production batch of flame-retardant polypropylene material; S2. The first particle group is subjected to a preset environmental cycle in particle form, and then the state of the first particle group is adjusted according to preset adjustment conditions. Then, the first particle group is injection molded according to a preset injection molding process to obtain the first sample. S3. Perform injection molding on the second particle group according to the preset injection molding process to obtain a second sample, and subject the second sample to the preset environmental cycle; S4. Without subjecting the reference particle group to the preset environmental cycle, perform injection molding on the reference particle group according to the preset injection molding process to obtain a reference sample; S5. Perform performance tests on the first sample, the second sample, and the reference sample according to preset test conditions to obtain the performance test results of each sample on the preset test items; S6. The differences between the performance test results of the first sample, the second sample and the reference sample are respectively determined as the storage and processing influence amount and the product service influence amount; S7. Determine the environmental sensitivity type of the flame-retardant polypropylene material based on the relative magnitude of the absolute values ​​of the storage and processing impact amount and the product service impact amount.

2. The method for testing the environmental adaptability of flame-retardant polypropylene by comparing the pre- and post-molding dual paths according to claim 1, characterized in that, S4 includes the following sub-steps: S41. Divide the reference particle component into a pre-reference portion and a post-reference portion; S42. In the same molding batch as the injection molding of the second particle group, the front reference part is injection molded according to the preset injection molding process to obtain the front reference sample, and the front reference sample is placed according to the preset placement conditions until the second sample completes the preset environmental cycle. S43. Within the same molding batch as the injection molding of the first particle group, the subsequent reference part is injection molded according to the preset injection molding process to obtain the subsequent reference sample; The reference sample includes the front reference sample and the back reference sample. In step S6, the reference sample that differs from the first sample is the back reference sample, and the reference sample that differs from the second sample is the front reference sample.

3. The method for testing the environmental adaptability of flame-retardant polypropylene by comparing two paths before and after molding according to claim 2, characterized in that, In step S6, the difference between the performance test results of the previous reference sample and the subsequent reference sample is determined as the cross-time drift calibration quantity. The test items whose absolute value of the cross-time drift calibration quantity does not exceed the preset resolvable difference are determined as valid control items. The storage and processing influence quantity and the product service influence quantity are determined only on the valid control items.

4. The method for testing the environmental adaptability of flame-retardant polypropylene by comparing two paths before and after molding according to claim 3, characterized in that, S6 includes the following sub-steps: S61. The preset detection items are divided into detection item groups according to the response mechanism, wherein the detection item groups include a degradation sensitive group, a crystallization and internal stress sensitive group, an additive and ratio sensitive group, and a surface appearance group. S62. For each of the effective control items, determine the sign of the storage and processing influence amount and the product service influence amount respectively, and determine the detection items with different signs and whose absolute values ​​of the storage and processing influence amount and the product service influence amount both exceed the preset distinguishable difference as mechanism separation items; S63. Divide the absolute values ​​of the storage and processing influence and the product service influence on each of the effective control items other than the mechanism separation item by the tolerance bandwidth of each of the effective control items in the acceptance specifications to obtain the storage and processing margin consumption ratio and the product service margin consumption ratio. S64. Perform intra-group weighted synthesis of the storage processing margin consumption ratio and the product service margin consumption ratio according to the test item group to obtain the storage processing group index and product service group index for each of the test item groups; S65. Perform inter-group weighted synthesis on each of the storage and processing group indices and each of the product service group indices to obtain the storage and processing sensitivity index and the product service sensitivity index.

5. The method for testing the environmental adaptability of flame-retardant polypropylene by comparing the pre- and post-molding paths according to claim 4, characterized in that, S7 includes the following sub-steps: S71. Divide the absolute value of the difference between the storage and processing sensitivity index and the product service sensitivity index by the mean of the storage and processing sensitivity index and the product service sensitivity index to obtain the sensitivity deviation ratio; S72. Determine the environmental effect sensitivity type based on the sensitivity deviation ratio, wherein S72 includes S72a, S72b, and S72c in parallel: S72a. In response to the sensitivity deviation ratio being less than a preset relative threshold, the environmental effect sensitivity type is determined to be a co-effect type; S72b. In response to the sensitivity deviation ratio being not less than the preset relative threshold and the storage and processing sensitivity index being greater than the product service sensitivity index, the environmental effect sensitivity type is determined to be the pre-molding sensitivity type. S72c. In response to the sensitivity deviation ratio being not less than the preset relative threshold and the product service sensitivity index being greater than the storage and processing sensitivity index, the environmental effect sensitivity type is determined to be post-molding sensitivity type.

6. The method for testing the environmental adaptability of flame-retardant polypropylene by comparing two paths before and after molding according to claim 1, characterized in that, In step S7, in response to the absolute value of the storage and processing influence being greater than the absolute value of the product service influence, the environmental effect sensitivity type is determined to be pre-molding sensitive; in response to the absolute value of the product service influence being greater than the absolute value of the storage and processing influence, the environmental effect sensitivity type is determined to be post-molding sensitive.

7. The method for testing the environmental adaptability of flame-retardant polypropylene by comparing two paths before and after molding according to claim 1, characterized in that, The preset adjustment conditions are conditions under which the first particle group is placed in a standard test environment until the moisture content reaches equilibrium. The temperature and relative humidity of the standard test environment are the same as the temperature and relative humidity of the preset detection conditions, and the state adjustment is performed at a temperature not higher than that of the standard test environment throughout the process.

8. The method for testing the environmental adaptability of flame-retardant polypropylene by comparing two paths before and after molding according to claim 1, characterized in that, The preset environmental cycle includes at least one of high temperature cycle, high humidity cycle, low temperature cycle and temperature and humidity alternation cycle. The preset environmental cycle is repeated a preset number of times, and the first particle group and the second sample undergo the same number of preset cycles.

9. The method for testing the environmental adaptability of flame-retardant polypropylene by comparing two paths before and after molding according to claim 1, characterized in that, The injection molding of the first particle group, the second particle group, and the reference particle group is performed on the same injection molding equipment and the same mold according to the preset injection molding process, wherein the preset injection molding process includes the temperature of each section of the barrel, the mold temperature, the injection pressure, the injection speed, the holding pressure, the holding time, and the cooling time.

10. The method for testing the environmental adaptability of flame-retardant polypropylene by comparing two paths before and after molding according to claim 1, characterized in that, The preset testing items include at least one of mechanical properties, rheological properties, thermal properties, flame retardant properties, and appearance. The mechanical properties include tensile properties, impact properties, and flexural properties; the rheological properties include melt flow rate; the thermal properties include heat distortion temperature; the flame retardant properties include vertical burning rating and glow wire test results; and the appearance includes color difference.

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