PBT-based organosilicon standard substance and preparation method thereof

Abstract

The invention discloses a PBT-based organosilicon standard substance and a preparation method thereof, and belongs to the technical field of high polymer materials, and the PBT-based organosilicon standard substance is characterized in that organosilicon with small molecular weight is introduced into PBT resin, white oil is compounded to serve as a dispersing agent, and the viscosity of the PBT resin is regulated, so that the organosilicon in the product can realize long-acting stability and dispersity; when being used as a standard substance, the organic silicon standard substance has good uniformity and stability and can be suitable for detection and control of organic silicon in a solid plastic material.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a PBT-based silicone reference material and a preparation method thereof. Background Art

[0002] Silicones are widely used in existing industrial products. Especially in plastic products, the introduction of silicones can improve the scratch resistance and electrical insulation performance of the products. However, silicones are highly harmful to the human body. At the same time, in some special application products such as relays, trace amounts of silicones in the material can cause breakdown failure of the product devices. Therefore, it is necessary to strictly detect and control the silicones in the products.

[0003] Most of the existing reference materials for detecting and controlling silicones are silicone standard solutions, that is, solutions are prepared with silicones or silicates, and then the silicone content of the analyte is analyzed by methods suitable for liquid standards such as GCMS and ICP-OES. However, silicone standard solutions are difficult to transport and store, have limited applicable detection methods, and it is difficult to simulate the dispersion state of silicones in solid plastic products, and it is impossible to synchronously and accurately detect and control the changes in the dispersion and content of silicones in solid products. On the other hand, when existing plastics, especially common plastic matrices such as PBT (polybutylene terephthalate) resin introduced with silicone ketone polymers, are compounded with silicone polymers to prepare composite materials, it is difficult to achieve long-term uniformity and stability, and they cannot be directly used as reference materials. Summary of the Invention

[0004] Based on the defects existing in the prior art, the purpose of the present invention is to provide a PBT-based silicone reference material. By introducing small molecular weight silicones into PBT resin, compounding white oil as a dispersant and regulating the viscosity of PBT resin, the silicones in the product can achieve long-term stability and dispersion, and there will be no dispersion deviation or even precipitation. When used as a reference material, it has good stability and uniformity, and is applicable to the detection and control of silicones in solid plastic materials.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A PBT-based silicone reference material, comprising the following components in parts by weight:

[0007] 60 - 70 parts of PBT resin, 0.05 - 0.2 parts of silicone, 20 - 30 parts of glass fiber, 0.5 - 3 parts of dispersant;

[0008] The molecular weight of the silicone ≤ 740;

[0009] The dispersant is white oil; the kinematic viscosity of the white oil ≤ 10 mm at 40 °C according to GB / T 265-19882 / s;

[0010] The intrinsic viscosity of the PBT resin at 25° C. is 0.8 to 0.9 dL / g.

[0011] As a plastic resin commonly used in daily electronic and electrical products, PBT has good mechanical strength and processing properties. However, the shrinkage uniformity of PBT resin itself during injection molding is low, and under normal conditions it is difficult to be used as a matrix raw material for preparing standard substances that need to meet the requirements of uniformity indicators. However, the use of silicone in existing electronic and electrical products is very common. If it is not monitored and controlled in real time, it will not only be detrimental to the long-term physical safety of product users, but it may even be difficult to detect device failure caused by silicone enrichment, which will eventually cause safety accidents. However, the existing standard substances for silicone monitoring and control are mostly liquid silicone solutions. Although this type of product can be configured in real time, it is difficult to transport and preserve, and there are certain limitations on the detection method. The dispersion of silicone in the liquid phase is also quite different from that of the actual solid product, and the adaptability is low when the object of action is a solid plastic product. Therefore, in the technical solution of the present invention, the inventor uses common PBT resin as the matrix, introduces specific glass fiber as the skeleton support component and regulates the viscosity of the PBT resin to maintain good processing shrinkage uniformity and stability, and at the same time introduces the organic silicon compound to prepare the plastic solid standard material of organic silicon. The dispersion of organic silicon in the product is similar to that of the actual plastic product containing organic silicon, and the monitoring and control accuracy is high. However, if the organic silicon and PBT resin are dispersed during the processing and mixing process to achieve the uniformity and stability accuracy required by the standard material, conventional organic silicon active substances and processing aids cannot be used, otherwise not only the batch uniformity cannot be achieved, but even after long-term storage, the organic silicon will precipitate or stratify. For this reason, in the product of the present invention, it is necessary to strictly control the molecular weight of organic silicon, and use a specific low-viscosity white oil as a dispersant. White oil is a saturated alkane processing aid, which has good compatibility with organic silicon and PBT resin, and can improve the internal lubricity during processing between components, so that the organic silicon can be evenly and stably dispersed in the matrix resin, and finally meet the index requirements of the standard material.

[0012] Preferably, among the components of the PBT-based organosilicon standard substance, the weight proportion of PBT resin is one of 60 parts, 62 parts, 64 parts, 65 parts, 66 parts, 68 parts, 70 parts or any two range values, the weight proportion of organosilicon is one of 0.05 parts, 0.1 parts, 0.15 parts, 0.18 parts, 0.2 parts or any two range values, the weight proportion of glass fiber is one of 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts or any two range values, and the weight proportion of dispersant is one of 0.5 parts, 0.8 parts, 1 parts, 1.5 parts, 2 parts, 3 parts or any two range values.

[0013] More preferably, in the PBT-based organosilicon standard substance, the mass percentage of PBT resin is ≥50%.

[0014] Preferably, the melting point of the PBT resin is 220-230°C.

[0015] Preferably, the organosilicon is organosiloxane, and the molecular weight of the organosiloxane is 200-745.

[0016] Specifically, the molecular weight of the organosiloxane is in the range of one or any two of 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 745.

[0017] The molecular weight of the organosiloxane is directly measured by mass spectrometry.

[0018] Preferably, the organosiloxane is at least one of hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6), tetradecamethylcycloheptasiloxane (D7), hexadecamethylcyclooctasiloxane (D8), octadecylcyclooctasiloxane (D9), octamethyltrisiloxane (L3), decamethyltetrasiloxane (L4), dodecamethylpentasiloxane (L5), tetradecamethylhexasiloxane (L6), and hexadecamethylheptasiloxane (L7).

[0019] Preferably, in the PBT-based organosilicon standard substance, the average retained length of the glass fiber is 200-400 μm, and the average retained diameter is 9-14 μm.

[0020] The average retained length and average retained diameter of the glass fiber in the PBT-based silicone standard substance are tested by the following method: the PBT-based silicone standard substance is calcined at 800°C in air, the obtained ash is filtered and washed, and then dispersed in a mixture of deionized water and ethanol in a mass ratio of 1:1. A two-dimensional microscope is used to observe, test and confirm the average retained length and average retained diameter of the glass fiber, 50 glass fibers are screened, and the average value is calculated.

[0021] Preferably, the kinematic viscosity of the white oil at 40°C according to GB / T 265-1988 is 2 to 10 mm 2 / s;

[0022] More preferably, the kinematic viscosity of the white oil at 40°C is 2 mm 2 / s, 2.5mm 2 / s、3mm 2 / s、3.5mm 2 / s, 4mm2 / s, 4.5 mm 2 / s, 5 mm 2 / s, 5.5 mm 2 / s, 6 mm 2 / s, 7 mm 2 / s, 8 mm 2 / s, 9 mm 2 / s, 10 mm 2 Range values of one or any two of / s.

[0023] More preferably, the kinematic viscosity of the white oil at 40 °C is 4 - 7 mm 2 / s.

[0024] The compatibility of white oils with different viscosities and fluidities with silicone varies, which in turn leads to certain differences in the stability of the product after long-term static settlement. After optimization, when the white oil is used as a dispersant, selecting the above types of kinematic viscosities can make the long-term stability of the prepared reference material better.

[0025] Preferably, the density of the white oil is 0.8 - 0.9 g / cm 3 .

[0026] Preferably, the components of the PBT-based silicone reference material further include 1 - 2 parts of functional additives.

[0027] More preferably, the processing additives include at least one of antioxidants, antistatic agents, antibacterial agents, and ultraviolet light resistant agents.

[0028] Those skilled in the art can add various different functional additives according to actual needs without affecting the homogeneity and stability of the reference material described in the present invention. For example, in order to prevent the product from being affected by static electricity during transportation and storage, those skilled in the art can add antistatic agents to the product; in order to improve the antioxidant effect of the product during storage, those skilled in the art can add antioxidants to the product.

[0029] More preferably, the components of the PBT-based silicone reference material further include 1 - 2 parts of antioxidants.

[0030] More preferably, the antioxidant includes at least one of hindered phenol antioxidants and phosphite antioxidants.

[0031] More preferably, the antioxidant is a mixture of hindered phenol antioxidants and phosphite antioxidants, and the mass ratio of the two is (0.8 - 1.2) : (0.8 - 1.2).

[0032] Another object of the present invention is to provide a method for preparing the PBT-based silicone reference material, comprising the following steps:

[0033] Add each component into a screw extruder for melt extrusion and pelletization, and then injection molding to obtain the PBT-based silicone reference material.

[0034] Preferably, the temperature zones of the screw extruder are set as follows: zone 1: 230 - 250 °C, zone 2: 210 - 230 °C, zone 3: 210 - 230 °C, zone 4: 190 - 210 °C, zone 5: 190 - 210 °C, zone 6: 180 - 200 °C, zone 7: 180 - 200 °C, zone 8: 170 - 190 °C, zone 9: 170 - 190 °C, zone 10: 150 - 170 °C. The screw rotation speed is 200 - 400 rpm, and the screw length-diameter ratio is (15 - 40):1.

[0035] The preparation method of the PBT-based silicone reference material of the present invention has simple operation steps and can achieve industrial-scale production.

[0036] Another object of the present invention is to provide the application of the PBT-based silicone reference material in the detection of the silicone content in solid plastic products and the evaluation and calibration of the equipment for testing the silicone content of samples.

[0037] The PBT-based silicone reference material of the present invention has high stability and uniformity. The dispersion of silicone in the matrix resin is similar to that in solid plastic products containing silicone, and it can be used as a reference sample for the detection of the silicone content in plastic solid samples under different types and application scenarios. It can also be used for the comparison of the detection results of other reference samples and the evaluation, verification, and calibration of testing equipment.

[0038] The beneficial effect of the present invention is that the present invention provides a PBT-based silicone reference material. By introducing small-molecular-weight silicone into the PBT resin, compounding white oil as a dispersant, and regulating the viscosity of the PBT resin, the silicone in the product can achieve long-term stability and dispersion, without dispersion deviation or even precipitation. When used as a reference material, it has good stability and uniformity and is applicable to the detection and control of silicone in solid plastic materials. Detailed Embodiments

[0039] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific examples and comparative examples. The purpose is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. The experimental reagents and instruments involved in the implementation of the present invention are all common ordinary reagents and instruments unless otherwise specified.

[0040] Examples 1 - 8

[0041] An embodiment of the PBT-based silicone reference material, its preparation method and application according to the present invention, the composition of the PBT-based silicone reference material is shown in Table 1.

[0042] The preparation method of the PBT-based silicone reference material includes the following steps:

[0043] Mix each component evenly, then melt extrude and pelletize in a screw extruder, and then inject mold to obtain the PBT-based silicone reference material.

[0044] The temperature zones of the screw extruder are set as Zone 1 at 240 °C, Zone 2 at 220 °C, Zone 3 at 220 °C, Zone 4 at 200 °C, Zone 5 at 200 °C, Zone 6 at 190 °C, Zone 7 at 190 °C, Zone 8 at 180 °C, Zone 9 at 180 °C, Zone 10 at 160 °C, the screw speed is 300 rpm, and the screw length-diameter ratio is 20:1.

[0045] Comparative Examples 1-7

[0046] The differences between each comparative example and the example are only in the types and ratios of the components, as shown in Table 2.

[0047] Among the components of each example and comparative example,

[0048] The PBT resin 1 is GX112 produced by Yizheng Chemical Fiber, and its intrinsic viscosity at 25 °C is 0.8 dL / g;

[0049] The PBT resin 2 is 1200-211M produced by Changchun, Taiwan, China, and its intrinsic viscosity at 25 °C is 0.84 dL / g;

[0050] The PBT resin 3 is GX111 produced by Yizheng Chemical Fiber, and its intrinsic viscosity at 25 °C is 0.7 dL / g;

[0051] The PBT resin 4 is 1100-211X produced by Changchun, Taiwan, China, and its intrinsic viscosity at 25 °C is 1.2 dL / g;

[0052] The silicone 1 is octamethylcyclotetrasiloxane (D4) produced by Shanghai Merck Chemical Technology Co., Ltd., with a purity of over 99% and a molecular weight of 296.62;

[0053] The silicone 2 is hexadecamethylcyclooctasiloxane (D8) produced by Shanghai Merck Chemical Technology Co., Ltd., with a purity of over 99% and a molecular weight of 593.23;

[0054] The silicone 3 is octakis(trimethylsiloxy)silsesquioxane produced by Shanghai Merck Chemical Technology Co., Ltd., with a purity of over 99% and a molecular weight of 1130.18;

[0055] The glass fiber is ECS11-03-534C produced by Taishan Fiberglass, with an average diameter of 11 μm and an average length of 3 mm;

[0056] The talcum powder is 1250 mesh, produced by Guangxi Longsheng Huamei Talc Development Co., Ltd., grade AH-1250N;

[0057] The dispersant 1 is No. 4 white oil produced by Maoming Runhua Petrochemical Co., Ltd., with a kinematic viscosity of 4.2 mm 2 / s at 40 °C;

[0058] The dispersant 2 is No. 5 white oil produced by Maoming Runhua Petrochemical Co., Ltd., with a kinematic viscosity of 6 mm 2 / s at 40 °C;

[0059] The dispersant 3 is No. 3 white oil produced by Maoming Runhua Petrochemical Co., Ltd., with a kinematic viscosity of 3.3 mm 2 / s at 40 °C;

[0060] The dispersant 4 is No. 7 white oil produced by Maoming Runhua Petrochemical Co., Ltd., with a kinematic viscosity of 8 mm 2 / s at 40 °C;

[0061] The dispersant 5 is No. 26 white oil produced by Maoming Runhua Petrochemical Co., Ltd., with a kinematic viscosity of 24.5 mm 2 / s at 40 °C;

[0062] The dispersant 6 is No. 32 white oil produced by Maoming Runhua Petrochemical Co., Ltd., with a kinematic viscosity of 33 mm 2 / s at 40 °C;

[0063] The antioxidant is a commercially available hindered phenol antioxidant and phosphite antioxidant: a mixture of antioxidant 168 and antioxidant 1010 mixed in a mass ratio of 1:1;

[0064] Unless otherwise specified, the component raw materials used in each example and comparative example of the present invention are all commercially available raw materials, and the component raw materials used in each parallel experiment are of the same kind.

[0065] For each example and comparative example except Comparative Example 5, the retained average length and retained average diameter of the glass fiber composition were tested. The test results were: the retained average length of the glass fiber in each product was 240-280 μm, and the retained average diameter was 10-11 μm, with a small difference rate, so they are not listed one by one.

[0066] Table 1

[0067]

[0068]

[0069] Table 2

[0070] Parts by weight Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 PBT Resin 1 67 67 67 67 67 PBT Resin 3 67 PBT Resin 4 67 Silicone 1 0.5 0.1 0.1 0.1 0.1 0.1 Silicone 3 0.1 Glass Fiber 30 30 30 30 30 30 Talc Powder 30 Dispersant 1 1 1 1 1 1 Dispersant 5 1 Dispersant 6 1 Antioxidant 1 1 1 1 1 1 1

[0071] To verify the performance of the products described in the present invention, the products prepared in each example and comparative example were subjected to the following performance tests. The specific steps are as follows:

[0072] (1) Uniformity test: According to CNAS-GL003-2018 "Guidelines for the Evaluation of the Homogeneity and Stability of Proficiency Testing Samples", the homogeneity between each test sample was analyzed by one-way analysis of variance. Taking the product of Example 1 as an example, 10 groups of prepared Example 1 samples were randomly selected. The above samples were extracted with acetone solvent at 120 °C and 3 MPa for 2 h, and the silicone was separated. The organic solvent was evaporated by heating in an electric blast drying oven, and 5 mL of nitric acid + 2 mL of hydrogen peroxide solution was added. Wet digestion was carried out using a microwave digestion instrument to convert the extracted silicone into inorganic silicon, and it was fixed volume to 50 mL with ultrapure water. Then, the content of silicon element brought by the accurate silicone was measured by ICP-OES method, and each group was tested 2 times; the samples of other examples and comparative examples were tested by the same method. According to the degrees of freedom and significance level, the homogeneity critical value F 0.05 (9,10) = 3.02. If the statistical value F < F 0.05 (9,10) = 3.02, it is considered that there is no significant difference between groups and within groups, that is, it indicates that the samples are homogeneous, and the smaller the value, the more homogeneous the product. If the F value ≥ the critical value F 0.05 (9,10) = 3.02, it indicates that the product has insufficient homogeneity;

[0073] (2) Stability test: According to CNAS-GL003-2018 "Guidelines for the Evaluation of the Homogeneity and Stability of Proficiency Testing Samples", the stability of the samples was tested by the consistency test between two means in the t-test method. After the standard sample was sealed and stored at room temperature in the dark for 6 months, 10 groups of samples were randomly selected from the standard sample, and acetone was used as the extraction solvent for extraction and treatment (the specific steps are the same as in step (1)). The content of silicon element brought by the silicone was measured by ICP-OES method, and the test results were analyzed by the t-test method. If the t value is less than the critical value t (0.05(20+20-2)) = 2.024, it indicates that there is no significant difference between the two groups of products, and the product has ideal stability; the smaller the t value, the higher the stability of the product; if the t value is greater than the critical value t (0.05(20+20-2)) , it indicates that the product does not have ideal stability.

[0074] As shown in Tables 3 and 4:

[0075] Table 3

[0076]

[0077] Table 4

[0078]

[0079] The test results are shown in Tables 5 and 6 as follows.

[0080] Table 5

[0081]

[0082] Table 6

[0083]

[0084]

[0085] It can be seen from Tables 5 and 6 that the homogeneity and stability of the PBT-based silicone reference material described in the present invention meet the standards and can be used as a solid reference material. This is mainly due to the high compatibility and uniform dispersion of the components in the product system. To achieve this effect, first, the viscosity of the matrix resin of the product needs to be adjusted according to the components and maintained within the range of 0.8 - 0.9 dL / g (25 °C). Otherwise, if the viscosity is too high or too low, as shown in Comparative Examples 2 and 3, the product cannot achieve good dispersion and stability of the components in the matrix resin. Secondly, when selecting silicone, the molecular weight should not be too high. As shown in Example 1, Example 4 and Comparative Example 4, silicone with a large molecular weight cannot achieve good dispersion in the product system, and the homogeneity and stability of the product do not meet the standards. In addition, the filler system and additive system in the product also need to be specifically selected. If a conventional filler system such as a talc powder system is selected, the product obtained, as shown in Comparative Example 5, is difficult to maintain long-term stability. And for the dispersant in the additives, a specific white oil needs to be selected to match the corresponding silicone-glass fiber composite system. If other conventional dispersant types are selected, as shown in Comparative Examples 6 and 7, the product also cannot meet the requirements of the reference material. When using white oil, if the kinematic viscosity at 40 °C is 4 - 7 mm 2 / s, it can be seen from the products of Example 1, Examples 5 - 8 that the homogeneity and stability of the product are better. However, the introduction of silicone in the product described in the present invention needs to follow a suitable ratio. If too much is introduced, as shown in Comparative Example 1, it cannot be effectively dispersed in the PBT resin, and the product still cannot meet the usage standards.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A PBT-based organosilicon standard substance, characterized in that: The composition comprises the following components in parts by weight: 60-70 parts of PBT resin, 0.05-0.2 parts of silicone, 20-30 parts of glass fiber, and 0.5-3 parts of dispersant; The molecular weight of the silicone is ≤745; The dispersant is white oil, and the kinematic viscosity of the white oil at 40° C. is ≤10 mm 2 / s; The intrinsic viscosity of the PBT resin at 25° C. is 0.8 to 0.9 dL / g.

2. The PBT-based organosilicon standard substance according to claim 1, characterized in that: The organosilicon is organosiloxane, and the molecular weight of the organosiloxane is 200-745.

3. The PBT-based organosilicon standard substance according to claim 1, characterized in that: The glass fiber has an average retained length of 200 to 400 μm and an average retained diameter of 9 to 14 μm.

4. The PBT-based organosilicon standard substance according to claim 1, characterized in that: The white oil has a kinematic viscosity of 2 to 10 mm at 40°C. 2 / s.

5. The PBT-based organosilicon standard substance according to claim 1, characterized in that: The components of the PBT-based organosilicon standard substance also include 1 to 2 parts of functional additives; preferably, the processing additives include at least one of an antioxidant, an antistatic agent, an antibacterial agent, and an anti-ultraviolet agent.

6. The PBT-based organosilicon standard substance according to claim 5, characterized in that: The antioxidant includes at least one of a hindered phenol antioxidant and a phosphite antioxidant.

7. The method for preparing a PBT-based organosilicon standard substance according to any one of claims 1 to 6, characterized in that: The following steps are involved: The components are added into a screw extruder for melt extrusion granulation and injection molding to obtain the PBT-based organosilicon standard substance.

8. Use of the PBT-based organosilicon standard substance according to any one of claims 1 to 6 in detecting the organosilicon content of solid plastic products and in evaluating and calibrating test equipment for the organosilicon content of samples.

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