A plastic standard sample for plastic load deflection temperature determination and a preparation method and application thereof

Abstract

The application discloses a plastic standard sample for plastic load deformation temperature determination. The plastic standard sample comprises the following components in parts by weight: 50-70 parts of polyamide resin, 30-50 parts of glass fiber, 0.1-1 part of coupling agent, 0.1-0.5 part of heat stabilizer and 0.1-1 part of nucleating agent. The length of the glass fiber is 80-350 microns. The nucleating agent is carboxylic acid metal salt nucleating agent and / or talc powder with a particle size D 50 ≤7.5 microns. The relative viscosity of the polyamide resin is 2.2-3.5 under the test conditions that the solvent is (96+ / -0.2) % concentrated sulfuric acid, the polyamide resin concentration is 0.01 g / mL and the temperature is 25 DEG C. The plastic standard sample has high heat deformation temperature, good sample uniformity and stability, wide adaptability and can meet the requirements of different test conditions in the heat deformation test standard.

Description

Technical Field

[0001] This invention belongs to the technical field of testing standard materials, and more specifically, relates to a plastic standard sample for determining the load deformation temperature of plastics, its preparation method, and its application. Background Technology

[0002] Load deformation temperature is an important indicator for evaluating the heat resistance of materials. It reflects the degree of deformation of polymers under heat load and is widely used in material performance evaluation. As product requirements increase, the demands for material performance evaluation testing are becoming increasingly stringent, requiring higher accuracy in testing.

[0003] Heat distortion temperature test results are affected by factors such as heat transfer medium, displacement sensor, temperature system, and operator technique. Routine equipment verification can only confirm the performance of individual modules. If anomalies are reported, verification can only be done step by step by checking each part of the equipment and the operator's actions, which is cumbersome and labor-intensive. However, by periodically testing standard samples, equipment can be verified and operator procedures standardized. This method is simple to operate, can promptly identify equipment problems and operator errors, and can also be used to trace the cause of test anomalies. It serves as an effective means of daily equipment status and personnel supervision.

[0004] For example, the Chinese patent "An ABS Substrate Standard Sample and Its Preparation Method and Application" discloses a standard sample prepared in an AS resin and ABS resin system. ABS resin is prepared by physically blending different proportions of ABS high-resin powder into acrylonitrile-styrene copolymer resin (SAN). This allows for adjustments to the load deformation temperature measurement range of the ABS substrate standard sample, while also improving its processability. This ABS substrate standard sample is uniform and stable, and its load deformation temperature can be measured, but the load deformation temperature of this standard sample does not exceed 100℃.

[0005] Furthermore, currently available heat distortion standards are mainly made of pure resin, with a relatively low heat distortion temperature range (<150℃) and poor uniformity and stability. As application scenarios become more diverse and performance requirements increase, more and more high-temperature samples need to be tested. However, there are currently no suitable standards for high-temperature testing, and while equipment calibration can verify individual equipment parameters, it cannot assess the overall testing capability. Therefore, providing a standard sample with uniformity, stability, and a high heat distortion temperature for inter-laboratory proficiency testing, internal laboratory accuracy verification of testing methods, instrument stability verification, quality control management, uncertainty assessment, and personnel competency evaluation has become extremely important. Summary of the Invention

[0006] In view of the above-mentioned existing technical problems, the primary objective of the present invention is to provide a plastic standard sample for measuring the heat distortion temperature of plastics. The plastic standard sample has a high heat distortion temperature, as well as good sample uniformity and stability, and has a wide range of adaptability, which can meet the requirements of different test conditions in the heat distortion test standard.

[0007] A second objective of this invention is to provide a method for preparing a plastic standard sample for measuring the load deformation temperature of plastics.

[0008] The third objective of this invention is to provide the application of the aforementioned plastic standard samples in the detection of plastic load deformation temperature and in the evaluation and calibration of plastic load deformation temperature testing equipment.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0010] A plastic standard sample for determining the load deformation temperature of plastics comprises, by weight, the following components: 50-70 parts polyamide resin, 30-50 parts glass fiber, 0.1-1 part coupling agent, 0.1-0.5 parts heat stabilizer, and 0.1-1 part nucleating agent; the glass fiber has a length of 80-350 μm; the nucleating agent is a metal carboxylate nucleating agent and / or a particle size D... 50 Talc powder with a particle size ≤7.5μm; under test conditions of 25℃, concentrated sulfuric acid with a solvent of (96±0.2)%, and polyamide resin concentration of 0.01g / mL, the relative viscosity of the polyamide resin is 2.2~3.5.

[0011] Through long-term research, the inventors discovered that plastic standard samples prepared by combining polyamide resin with a specific range of relative viscosity, glass fibers of a specific length, and specific nucleating agents, coupling agents, and heat stabilizers within a polyamide resin system not only exhibit high heat distortion temperatures but also excellent uniformity and stability, meeting the requirements of various testing conditions in the standard. The inventors found that when the length of the glass fibers in the plastic standard sample is within a specific range, the plastic standard sample exhibits a high heat distortion temperature, as well as good stability and uniformity. Too short a glass fiber length leads to a lower heat distortion temperature, while too long a length affects melt flowability, thus impacting the injection-molded appearance quality and dimensional stability of the standard sample. The inventors also found that in the polyamide system, the use of carboxylic acid metal salt nucleating agents or talc powder of a specific particle size allows for good wetting and adsorption, good compatibility with the polymer, and uniform dispersion in the polymer melt. Furthermore, by optimizing the relative viscosity of the polyamide resin and combining it with coupling agents and heat stabilizers, the inventors further ensured the uniformity and stability of the plastic standard samples. The plastic standard samples were tested under the conditions of Method A and Method B in ISO 75-1:2013 or ISO 75-2:2013. The final plastic standard samples had a load deformation temperature between 200 and 260°C, which meets the requirements for equipment inspection in high-temperature areas. At the same time, the homogeneity and stability of the samples met the requirements for evaluating the homogeneity and stability of proficiency testing samples in CNAS-GL003.

[0012] Specifically, the test method for the relative viscosity of the polyamide resin is ISO 307-2019.

[0013] Specifically, the length of the glass fiber refers to the retained length of the glass fiber in the sample. The test method for the retained length of the glass fiber in the sample is as follows: the sample is ignited at 600℃ for 30 minutes, and then the residue is uniformly dispersed in water. The sample is then tested using a glass fiber retention length tester, and the average length of the glass fiber is calculated by software, which is the retained length of the glass fiber.

[0014] Preferably, the polyamide resin is one or more of PA6, PA66, PA610 or PA656.

[0015] More preferably, the polyamide resin is PA6. Within this preferred range, the load deformation temperature of the plastic standard sample is 200–230°C, which better meets the needs of daily practical use.

[0016] Preferably, the length of the glass fiber is 100–300 μm.

[0017] Preferably, the nucleating agent has a particle size D. 50 Talc powder with a particle size of ≤7.5μm.

[0018] Preferably, the particle size D of the talc powder is... 50 The range is 0.5–4.0 μm.

[0019] Preferably, the glass fiber is selected from one or more of E glass fiber, A glass fiber, S glass fiber, D glass fiber, C glass fiber or quartz glass fiber.

[0020] Preferably, the coupling agent is selected from one or more of vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, hexamethyldisilazane, dimethyldimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-aminopropyltrimethoxysilane, or γ-aminopropyltriethoxysilane. The coupling agent can improve the interfacial bonding between glass fiber and resin, enhance the bond between the resin and glass fiber, and improve the heat distortion, thereby increasing the stability of the material and improving the appearance of the sample.

[0021] Preferably, the heat stabilizer is selected from one or more of hindered phenol stabilizers, phosphite stabilizers, hindered amine stabilizers, cuprous halide composite stabilizers, or stabilizers containing benzophenone functional groups.

[0022] Furthermore, the present invention also provides a method for preparing a plastic standard sample, wherein polyamide resin, coupling agent, heat stabilizer and nucleating agent are mixed evenly, added to an extruder and glass fiber is added, melt extruded, granulated, and then injection molded through a standard mold to obtain the plastic standard sample.

[0023] Preferably, the temperature of the melt extrusion is 150–250°C.

[0024] More preferably, the temperature of the melt extrusion is: Zone 1 (150-170)℃, Zone 2 (220-240)℃, Zone 3 (210-230)℃, Zone 4 (210-230)℃, Zone 5 (200-220)℃, Zone 6 (200-220)℃, Zone 7 (200-220)℃, Zone 8 (210-230)℃, Zone 9 (210-230)℃, and die head (230-250)℃.

[0025] Preferably, the extrusion speed is 500-800 rpm.

[0026] Preferably, the length-to-diameter ratio of the extruder is 36 to 44:1.

[0027] Furthermore, the present invention also claims protection for the application of the above-mentioned plastic standard samples in the detection of plastic load deformation temperature and in the evaluation and calibration of plastic load deformation temperature testing equipment.

[0028] Compared with existing technologies, the present invention has the following advantages: The present invention provides a plastic standard sample, which not only has a high load deformation temperature, but also achieves uniformity and stability, meeting the requirements of different test conditions in the standard. Under the conditions of Method A (1.80 MPa) and Method B (0.45 MPa) in ISO 75-1:2013 or ISO 75-2:2013, the load deformation temperature of the plastic standard sample reaches between 200 and 260°C, meeting the requirements for equipment inspection in high-temperature areas; the uniformity and stability of the plastic standard sample both meet the requirements for evaluating the uniformity and stability of proficiency testing samples in CNAS-GL003. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0030] Description of raw materials for examples and comparative examples:

[0031] Polyamide resin 1, under test conditions of 25℃, solvent (96±0.2)% concentrated sulfuric acid, and polyamide resin concentration of 0.01g / mL, has a relative viscosity of 2.8. It is PA6 M2800 grade and manufactured by Xinhui Meida Company.

[0032] Polyamide resin 2, under test conditions of 25℃, solvent (96±0.2)% concentrated sulfuric acid, and polyamide resin concentration of 0.01g / mL, has a relative viscosity of 4.0. It is PA6 BL40H grade and manufactured by Yueyang Petrochemical Company.

[0033] Polyamide resin 3, under test conditions of 25℃, solvent (96±0.2)% concentrated sulfuric acid, and polyamide resin concentration of 0.01g / mL, has a relative viscosity of 2.0. It is PA6 M2000 grade and manufactured by Xinhui Meida Company.

[0034] Polyamide resin 4, under test conditions of 25℃, solvent (96±0.2)% concentrated sulfuric acid, and polyamide resin concentration of 0.01g / mL, has a relative viscosity of 2.7. It is PA66 EP-158 grade and produced by Huafeng Group Co., Ltd.

[0035] Fiberglass, 3.0mm in length, ECS10-03-568H grade, Jushi Company.

[0036] Nucleating agent 1, talc, particle size D 50 It is 3.5μm, HTP3 grade, from Imfabi Company.

[0037] Nucleating agent 2, talc, particle size D50 It has a thickness of 7.0 μm, is grade HM4, and is manufactured by Imfabi.

[0038] Nucleating agent 3, sodium carboxylate nucleating agent, LICOMONT NAV101 PWD grade, Clariant Corporation.

[0039] Nucleating agent 4, talc, particle size D 50 It has a thickness of 12.3 μm, is grade AH1250-N6, and is produced by Guangxi Longsheng Huamei Talc Development Co., Ltd.

[0040] Nucleating agent 5, carbon black, grade M717, Cabot Corporation.

[0041] Nucleating agent 6, calcium carboxylate nucleating agent, LICOMONT CAV102, Clariant.

[0042] Coupling agent, γ-aminopropyltriethoxysilane, commercially available.

[0043] Heat stabilizer, hindered phenolic stabilizer, commercially available.

[0044] Unless otherwise specified, all components (e.g., coupling agents, heat stabilizers) used in each parallel example and comparative example are the same commercially available products.

[0045] Example 1

[0046] A method for preparing a plastic standard sample, comprising the following steps:

[0047] (1) Weigh each raw material component according to the weight proportions in Table 1. Use a high-speed mixer to mix the dried raw material components (except for glass fiber) evenly. Add the mixture from the main feed port of the twin-screw extruder, and add the glass fiber from the side feed port. The melt extrusion conditions of the twin-screw extruder are: Zone 1 160℃, Zone 2 230℃, Zone 3 220℃, Zone 4 220℃, Zone 5 210℃, Zone 6 210℃, Zone 7 210℃, Zone 8 220℃, Zone 9 220℃, and die head 240℃; main machine speed 600 r / min; length-to-diameter ratio of the twin-screw extruder 40:1; melt extrusion, granulation, and injection molding to obtain plastic granules, which are then injection molded into ISO 1000 granules. 75:2013 requires a standard sample (where the retained length of glass fiber is 200 μm, and the test method is as follows: plastic particles are burned at 600℃ for 30 min, and then the residue is uniformly dispersed in water, tested with a glass fiber retained length tester, and the average length of glass fiber is calculated by software to obtain the value of the retained length of glass fiber).

[0048] Examples 2-10

[0049] The weight proportions of raw materials used in the following embodiments are shown in Table 1. The following embodiments use the same preparation method.

[0050] The difference between Example 2 and Example 1 is that the length-to-diameter ratio of the twin-screw extruder is 36:1, and the retained length of the glass fiber is 320 μm.

[0051] The difference between Example 10 and Example 1 is that the length-to-diameter ratio of the twin-screw extruder is 44:1; and the retained length of the glass fiber is 80 μm.

[0052] Comparative Examples 1-11

[0053] The weight proportions of raw materials used in each comparative example are shown in Table 2. The specific preparation steps for each comparative example are the same as those in Example 1.

[0054] The difference between Comparative Example 5 and Example 1 is that the length-to-diameter ratio of the twin-screw extruder is 48:1, and the retained length of the glass fiber is 50 μm.

[0055] The difference between Comparative Example 11 and Example 1 is that the aspect ratio of the twin-screw extruder is 32:1, and the retained length of the glass fiber is 400 μm.

[0056] Table 1 shows the formulation components of each embodiment:

[0057] Table 1

[0058]

[0059] Table 2 shows the formulation components for each comparative example:

[0060] Table 2

[0061]

[0062] The plastic standard samples prepared in the above embodiments and comparative examples were tested according to the following test methods:

[0063] 1. Uniformity Test: In accordance with CNAS-GL003:2018 "Guideline for Evaluation of Uniformity and Stability of Proficiency Testing Samples", one-way ANOVA was used to test the uniformity between samples. Ten groups of prepared samples were randomly selected, with two standard samples in each group. The standard samples were conditioned in a constant temperature and humidity chamber at (23±2)℃ and (50±5)%RH for 24 hours before testing.

[0064] The calculation method is as follows:

[0065] The average test value for each group of samples:

[0066] The overall average value of all sample tests:

[0067] Total number of tests: N = 20;

[0068] Sum of squares between samples: Mean square:

[0069] Intra-sample sum of squares: Mean square:

[0070] Degrees of freedom: f1 = m - 1 = 10 - 1 = 9; f2 = Nm = 20 - 10 = 10; Statistics:

[0071] If F < the critical value F with degrees of freedom (f1, f2) and a given significance level α (usually α = 0.05). α If (f1, f2) is a constant, it indicates that there is no significant difference within or between samples, and the samples are homogeneous.

[0072] 2. Stability Test: In accordance with CNAS-GL003:2018 "Guideline for Evaluation of Homogeneity and Stability of Proficiency Testing Samples", the consistency between two means in the t-test method was used to test the stability of the samples. The standard samples were stored in an environment of (23±2)℃ & (50±5)%RH, and five groups of samples (two samples in each group) were randomly selected on days 0 and 30 for direct testing.

[0073] The t-value was calculated based on the proficiency testing uniformity stability formula (the following formula), and the measurement results and data calculation summary results are shown in Tables 3 and 4.

[0074] In the formula: —The average value of the measurement data from the first test;

[0075] —The average value of the measurement data from the second test;

[0076] s1_——Standard deviation of the measurement data in the first test;

[0077] s2—Standard deviation of the measurement data from the second test;

[0078] n1 — The number of measurements in the first test measurement;

[0079] n2 — The number of measurements in the second test.

[0080] Note: To ensure the accuracy of the mean and standard deviation, both n1 and n2 are ≥6.

[0081] If t < significance level α (usually α = 0.05), the critical value t with degrees of freedom is n1 + n2 - 2. a(n1+n2-2) If the two means are not significantly different, then there is no significant difference between them.

[0082] Table 3 below shows the test results of each embodiment using Method A (1.80 MPa) in ISO 75:2013.

[0083] Table 3

[0084]

[0085] Table 4 below shows the results of the tests conducted using Method A (1.80 MPa) in ISO 75:2013 for each comparative example.

[0086] Table 4

[0087]

[0088]

[0089] As shown in Table 3, the F values ​​of the plastic standard samples prepared in Examples 1-10 are less than F. 0.05 (9,10) indicates that there are no significant differences within and between plastic standard samples, and the samples are homogeneous; the plastic standard samples prepared in Examples 1-10 have t < t 0.05(18) The result indicates that there is no significant difference between the two average values, and the plastic standard sample has good stability.

[0090] Compared to Example 1, the glass fiber retention length in Example 2 was 320 μm, and the uniformity of the plastic standard sample in Example 2 was not as good as that in Example 1. In Example 3, a particle size D was used. 50 The talc powder used in Example 3 had a uniformity comparable to that in Example 1, with a particle size of 7.0 μm. Example 4 used sodium carboxylate nucleating agent, and the uniformity of its plastic standard sample was significantly different from that of Example 1. Example 5 used polyamide resin PA66. Compared to Example 1, the load deformation temperature obtained using PA66 resin was much higher than that in Example 1 (greater than 230°C), approaching the vapor volatilization point of dimethyl silicone oil, and its uniformity was worse than that of the plastic standard sample in Example 1.

[0091] Comparative Examples 1-4 are comparative examples lacking glass fiber, coupling agent, heat stabilizer, and nucleating agent, respectively. Compared with Example 1, the plastic standard sample prepared in Comparative Example 1 has poorer uniformity and stability, failing to meet the requirements, and its plastic load deformation temperature is much lower than that of the sample prepared in Example 1. The plastic load deformation temperatures of the plastic standard samples prepared in Comparative Examples 2 and 4 differ to some extent from those in Example 1, and the uniformity and stability of the samples in Comparative Examples 3 and 4 are also poor, failing to meet the requirements.

[0092] Comparative Examples 5 and 11 are comparative examples where the glass fiber retention length is outside the range of 80–350 μm. A comparison of the data from Comparative Example 5 and Example 1 shows that the retention length of the glass fiber affects the load deformation temperature and exhibits poor uniformity. A comparison of the data from Comparative Example 11 and Example 1 shows that when the retention length of the glass fiber reaches a certain level, its influence on the load deformation temperature decreases, and its main impact is manifested in poor uniformity and stability.

[0093] Comparative Examples 7 and 8 were prepared using plastic standard samples with relative viscosities outside the range of 2.2 to 3.5. The load deformation temperatures of the prepared samples were similar to those of Example 1, but their uniformity and stability were worse than those of Example 1. Comparative Example 9 used a particle size D... 50 The uniformity and stability of plastic standard samples prepared from talc powder with a particle size of 12.3 μm are difficult to meet the requirements.

[0094] Comparative Example 10 is a comparative example in which glass fiber is in excess. Although the load deformation temperature of the plastic standard sample prepared by it meets the requirements of this application, its uniformity is worse than that of Example 1 and does not meet the requirements.

[0095] The foregoing examples are merely illustrative, used to explain some features of the method described in this invention. The appended claims are intended to claim the broadest possible scope, and the embodiments presented herein are demonstrated by the applicant's actual experimental results. Therefore, the applicant intends that the appended claims are not limited by the selection of examples illustrating the features of the invention. Some numerical ranges used in the claims also include sub-ranges within them, and variations within these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A plastic standard sample for determining the load deformation temperature of plastics, characterized in that, By weight, it comprises the following components: 50-70 parts polyamide resin, 30-50 parts glass fiber, 0.1-1 part coupling agent, 0.1-0.5 parts heat stabilizer, and 0.1-1 part nucleating agent; The length of the glass fiber is 80–350 μm; The nucleating agent is a carboxylate metal salt nucleating agent and / or a particle size D. 50 Talc powder with a particle size ≤7.5μm; Under test conditions of 25°C, (96±0.2)% concentrated sulfuric acid as solvent, and 0.01 g / mL polyamide resin concentration, the relative viscosity of the polyamide resin is 2.2–3.

5. The length of the glass fiber refers to the length of the glass fiber retained in the plastic standard sample.

2. The plastic standard sample according to claim 1, characterized in that, The polyamide resin is one or more of PA6, PA66, and PA610.

3. The plastic standard sample according to claim 1, characterized in that, The polyamide resin is PA6.

4. The plastic standard sample according to claim 1, characterized in that, The glass fiber has a length of 100–300 μm.

5. The plastic standard sample according to claim 1, characterized in that, The nucleating agent has a particle size D. 50 Talc powder with a particle size of ≤7.5μm.

6. The plastic standard sample according to claim 5, characterized in that, The particle size D of the talc powder 50 The range is 0.5–4.0 μm.

7. The plastic standard sample according to claim 1, characterized in that, The coupling agent is selected from one or more of vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, hexamethyldisilazane, dimethyldimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, γ-aminopropyltrimethoxysilane, or γ-aminopropyltriethoxysilane.

8. The plastic standard sample according to claim 1, characterized in that, The heat stabilizer is selected from one or more of the following: hindered phenol stabilizers, phosphite stabilizers, hindered amine stabilizers, cuprous halide composite stabilizers, or stabilizers containing benzophenone functional groups.

9. The method for preparing the plastic standard sample according to any one of claims 1 to 8, characterized in that, Polyamide resin, coupling agent, heat stabilizer and nucleating agent are mixed evenly, added to an extruder and glass fiber is added, melt extruded, granulated and injection molded to obtain the plastic standard sample.

10. The application of the plastic standard sample according to any one of claims 1 to 8 in the detection of plastic load deformation temperature and the evaluation and calibration of plastic load deformation temperature testing equipment.

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