An anti-abnormal noise polycarbonate material and its preparation method

Abstract

The present invention relates to an anti-abnormal-noise polycarbonate material. The anti-abnormal-noise polycarbonate material of the present invention comprises polycarbonate, hindered phenol, toughening agent, antioxidant, and lubricant. By blending and modifying the organic hindered phenol small molecule with PC, the damping performance of the material is greatly enhanced; due to the existence of hydrogen bond, while improving the damping performance of the alloy system, the modulus of the material is also increased. The preparation process of the present invention is simple, without complex process steps, and the prepared product has high strength, is non-toxic and harmless, does not release toxic and harmful gases to the environment, and has a wide range of applications.

Description

Technical Field

[0001] The present invention belongs to the field of materials, and particularly relates to an anti-abnormal sound polycarbonate material and a preparation method thereof. Background Art

[0002] In recent years, industries such as the automotive industry in China have developed very rapidly. Polycarbonate (PC) materials have the advantages of high heat resistance, good toughness, high transparency, etc., and are widely used in the automotive and other industries. However, when parts made of PC materials are vibrating during vehicle driving or are subjected to external force extrusion, abnormal "squeaking" sounds are likely to occur. This kind of sound may come from the friction between plastic parts, or from the friction between plastic parts and other parts. When the parts are subjected to external forces, a stick-slip phenomenon occurs. The plastic parts change from the static friction state of adhesion to sliding contact, and energy is released during this process. The occurrence of stick-slip cycles causes the material to vibrate and generate abnormal sounds.

[0003] Damping performance refers to the ability of solid mechanical vibration energy to be converted into heat energy, and is mainly used for vibration and noise control. The better the damping performance of a material, the more friction work is converted into internal energy, and the smaller the abnormal sound of the material. The damping mechanism of polymer materials is related to their own dynamic relaxation properties. When a polymer material is subjected to an alternating stress, due to the internal friction during the movement of the chain segments, the deformation usually lags behind the change of the stress, generating a phase difference δ (hysteresis angle). From the mechanism of damping generation, factors that can increase the internal friction of molecules can improve the damping performance of the material.

[0004] The narrow effective damping temperature range of polycarbonate cannot fully meet the application requirements. Therefore, damping modification treatment is required. In this patent, the polycarbonate material is subjected to damping modification by an organic hybridization method, and a material with a wide-temperature-range damping effect is obtained, which can be applied to the surfaces of various vibrating objects such as automobiles and high-speed trains to achieve the effect of vibration reduction and noise reduction.

[0005] At the present stage, the main engine factories mainly solve the friction abnormal sound of parts by increasing felt barriers, coating lubricating oil, using rubber gaskets, etc. at the contact parts. However, this not only increases the labor cost, but also prolongs the production cycle of the product. Therefore, noise reduction modification has become the focus of attention of plastic modification manufacturers. However, hindered amines cannot be used in PC materials, as it will cause obvious degradation, resulting in a significant reduction in various properties of the material. At present, there is no research on the functional effects of different types and dosages of hindered phenol small molecules on anti-abnormal sound in automotive PC materials. Summary of the Invention

[0006] The object of the present invention is to provide an anti-abnormal sound polycarbonate material and a preparation method thereof for the problem of how to achieve noise reduction in automotive PC materials.

[0007] PC resin has high heat resistance and is mostly used in automotive interiors. However, it is also prone to generating abnormal noises. In this invention, hindered phenol is used to modify PC. But PC material has notch sensitivity and thickness sensitivity, and the influence of hydrogen bond density in PC material on toughness needs to be considered. When hindered phenol is used in PC, the impact strength will be reduced due to hydrogen bond interaction, which also affects the toughness of the product. The PC resin material containing only hindered phenol will become hard / brittle. Therefore, PC material cannot simply rely on adding these small molecules (hindered phenol) to improve abnormal noise prevention. If the hydrogen bond density is too high, the material will be too brittle and it is also difficult to directly use it to make products. In this invention, the toughness of the material is further improved by adding an additive that has both toughening effect and certain noise reduction effect. At the same time, through the hydrogen bond interaction of hindered phenol and the combined action with the additive, a better noise reduction effect is achieved. In addition, the addition of the additive will cause a decrease in heat resistance, while the addition of hindered phenol enhances the high temperature resistance of the material. Only through their synergistic effect can the requirements of this invention be met.

[0008] The object of the present invention can be achieved through the following solutions:

[0009] The present invention provides an abnormal noise prevention polycarbonate material, and the abnormal noise prevention polycarbonate material comprises the following components in parts by weight: 100 parts of polycarbonate, 10 - 40 parts of hindered phenol, 2 - 5 parts of toughening agent, 0.1 - 2 parts of antioxidant, and 0.5 - 2 parts of lubricant.

[0010] As an embodiment of the present invention, the abnormal noise prevention polycarbonate material comprises the following components in parts by weight: 100 parts of polycarbonate, 20 - 40 parts of hindered phenol, 3 - 5 parts of toughening agent, 0.1 - 1 part of antioxidant, and 0.5 - 1.5 parts of lubricant; more preferably, the parts by weight of the abnormal noise prevention polycarbonate material are: 100 parts of polycarbonate, 20 - 30 parts of hindered phenol, 4 - 5 parts of toughening agent, 0.1 - 0.5 part of antioxidant, and 0.5 - 1 part of lubricant.

[0011] As an embodiment of the present invention, the polycarbonate is bisphenol A type polycarbonate resin, and the mass melt flow rate under the test conditions of 300°C and 1.2 kg is 10 - 20 g / 10 min.

[0012] As an embodiment of the present invention, the hindered phenol is one or more of 4,4'-thiobis(6-tert-butyl-3-methylphenol) (AO-300), 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propanoyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (AO80), and hindered phenol AO60. For the hindered phenol selected in the present invention, the final hydrogen bond density needs to be considered, and not every hindered phenol is applicable. Different from other materials, although PC itself has good toughness, it has obvious notch sensitivity and thickness sensitivity. In actual use, not only the damping effect brought by hydrogen bonds needs to be considered, but also the loss in toughness needs to be comprehensively considered. If the hindered phenol used (such as AO300) has a high hydrogen bond density, the elongation at break decreases significantly and the material becomes more brittle. Therefore, the hydrogen bond density of the hindered phenol in the present invention is appropriate. Too low cannot play a role in improving the damping performance, and too high will affect the performance of the final material.

[0013] As an embodiment of the present invention, the toughening agent is one or several of methyl methacrylate, butadiene, styrene terpolymer, and ethylene-acrylate copolymer.

[0014] As an embodiment of the present invention, the antioxidant is one or several of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(2,4-di-tert-butyl)phenyl phosphite, and distearyl pentaerythritol diphosphite.

[0015] As an embodiment of the present invention, the lubricant is one or several of silicone oil, silicone powder, paraffin wax, stearic acid, butyl stearate, oleamide, and ethylene bisstearamide.

[0016] The present invention also provides a preparation method of an anti-abnormal sound polycarbonate material, and the preparation method specifically includes the following steps:

[0017] (1) Prepare each component according to the following parts by weight: 100 parts of polycarbonate PC, 10-40 parts of hindered phenol, 2-5 parts of toughening agent, 0.1-2 parts of antioxidant, and 0.5-2 parts of lubricant;

[0018] (2) For the materials prepared in step (1), mix them evenly in a high-speed mixer, and then add the uniformly mixed materials into a twin-screw extruder for melt blending and extrusion. Control the extrusion temperature at 180-250 °C, the screw speed at 200-500 rpm, and the pressure at 2-3 MPa, and extrude and pelletize to obtain the anti-abnormal sound polycarbonate material.

[0019] As an embodiment of the present invention, the high-speed mixer rotates at a speed of 100 - 300 r / min and mixes for 10 - 30 min.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) By blending and modifying organic hindered phenol small molecules with PC, the damping performance of the material is greatly enhanced;

[0022] (2) Due to the existence of hydrogen bond interaction, while improving the damping performance of the alloy system, the modulus of the material is also increased;

[0023] (3) The preparation process is simple, without complex process steps. The prepared product has high strength, is non-toxic and harmless, does not release toxic and harmful gases to the environment, and has a wide range of applications. Description of the Drawings

[0024] By reading the following detailed description of the non-limiting embodiments with reference to the accompanying drawings, other features, objectives, and advantages of the present invention will become more apparent:

[0025] Figure 1 It is a structural diagram of a friction abnormal noise test tooling. Detailed Embodiments

[0026] The present invention will be described in detail below with reference to the drawings and specific embodiments. The following examples are implemented on the premise of the technical solution of the present invention, providing detailed implementation manners and specific operation processes, which will help those skilled in the art to further understand the present invention. It should be noted that the protection scope of the present invention is not limited to the following embodiments. Several adjustments and improvements made under the premise of the concept of the present invention all belong to the protection scope of the present invention.

[0027] Examples 1 - 6

[0028] A method for preparing an anti-abnormal noise polycarbonate material, the method comprising the following steps:

[0029] (1) Prepare each component according to the parts by weight in Table 1;

[0030] (2) Preparation of hybrid plastic: Mix polycarbonate plastic particles, hindered phenol small molecules, toughening agent, antioxidant, and lubricant evenly in a high-speed mixer, and add the uniformly mixed material into a twin-screw extruder for melt blending and extrusion. Control the extrusion temperature at 180 - 250 °C, the screw speed at 200 - 500 rpm, and the pressure at 2 - 3 MPa. After underwater pelletizing and drying, the product is obtained;

[0031] Among them, the material composition of Table 1 is as follows:

[0032] Component A1 is polycarbonate PC7019J, Mitsubishi, Japan;

[0033] Component B1 is the hindered phenol AO80, from Shanghai Zhaoheng;

[0034] Component B2 is the hindered phenol AO300, from Shanghai Zhaoheng;

[0035] Component C1 is the toughening agent 4700, from Arkema;

[0036] Component C2 is the toughening agent S2006, from Mitsubishi;

[0037] Component D is the antioxidant IRGANOX 1010, from BASF;

[0038] Component E is the lubricant silicone powder GM-100, from Chenguang.

[0039] Explanation for the compilation of Table 1 (hybrid plastics):

[0040] For Examples 1 to 4, the PC and the grades of hindered phenols are the same, and the difference lies in the different dosages of hindered phenols, which is used to illustrate that the dosage of hindered phenols will affect the damping performance of the resin. The structural formulas of the hindered phenols are shown in Formulas 1 and 2.

[0041]

[0042] For Examples 5 to 8, the PC grades are the same, and the difference lies in the different types of hindered phenols, which is used to verify the influence of the types of hindered phenols on the damping performance of the resin.

[0043] Comparative Example 1

[0044] This comparative example is basically the same as Example 1, except that: no small molecule of hindered phenol is added.

[0045] Comparative Example 2

[0046] This comparative example is basically the same as Example 2, except that: no toughening agent is added.

[0047] Comparative Example 3

[0048] This comparative example is basically the same as Example 2, except that: the toughening agent is replaced with the silicone / acrylic ester toughening agent S2006.

[0049] Performance testing

[0050] Physical properties: After the composition particles prepared in the above comparative examples and examples are fully dried, according to the ISO standard, they are injection molded into test specimens under the same injection molding conditions, and the physical properties of each resin composition are tested. Among them, the tensile properties of the resin are tested based on the ISO 527 standard, and the test speed is 50 mm / min.

[0051] RPN Abnormal Noise Test: The test is conducted according to the standard VDA230-206. The contact area between the sample to be tested and the friction surface is 1250mm 2 , the sliding distance is fixed at 50mm, the sliding speeds are 1mm / s and 4mm / s, and the loads are 10N and 40N. Before the test, the sample is conditioned in an environment of (23(2)°C, (50(5)%RH) for more than 24 hours.

[0052] Friction Abnormal Noise Test: The test equipment is self-built by Kingfa Sci & Tech Co., Ltd. The designed tooling structure is as Figure 1 shown. When friction occurs between the indenter and the sample plate, typical stick-slip phenomena are likely to occur, resulting in vibration and noise. The sound sensor is placed 5cm away from the sample plate to be tested to collect sound parameters, that is, the loudness heard by the human ear.

[0053] Table 1 Weight Fraction Contents of Each Component of Hybrid Plastics

[0054]

[0055] Table 2 Abnormal Noise Performance Parameters of Hybrid Plastics

[0056]

[0057] RPN is the product of the frequency of event occurrence, severity, and detection level, and is called the risk coefficient. The larger the RPN, the more serious the potential problem. Generally, it is considered that when RPN = 1 - 3, the risk of abnormal noise in the material is relatively small; when RPN = 4 - 5, the material has a medium risk of abnormal noise; when RPN = 6 - 10, the material has a relatively high risk of abnormal noise. The RPN values of polycarbonate materials with different types and dosages of hindered phenols are shown in Table 2. It can be seen that the RPN values of the hybrid plastic system modified by adding hindered phenol small molecules are all within 1 - 3, indicating that the risk of abnormal noise in the material is relatively low. In addition, as the content of hindered phenol increases, the loudness heard by the human ear also decreases.

[0058] Table 3 Physical and Mechanical Properties of Hybrid Plastics

[0059]

[0060] Table 3 lists the tensile mechanical properties of hybrid plastics. It can be seen that as the dosage of hindered phenol small molecules increases, the presence of hydrogen bonds endows this hybrid rubber system with high damping performance. At the same time, due to the hydrogen bond strength, the tensile mechanical properties are also improved; as the dosage of hindered phenol increases from 10 parts to 40 parts, the tensile strength increases and the elongation at break decreases because when the content of hindered phenol is too high, the hydrogen bond density is too high.

[0061] From the comparative analysis of the damping performance test results of Examples 1 to 4 and Comparative Example 1, it can be seen that as the addition amount of the organic hindered phenol small molecule increases, the RPN value of the system decreases and the human ear loudness decreases. At the same time, by comparing Examples 5 to 8, it is found that the AO300 / PC hybrid system has a greater reduction amplitude, which may be due to the different hydrogen bond concentrations caused by the different structures of the two small molecules. However, considering the impact on the tensile mechanical properties, it is not recommended that the content of hindered phenol be higher than 40 parts.

[0062] From the comparative analysis of Example 2 and Comparative Example 2, it can be seen that when the toughening agent is not added, the elongation at break decreases greatly, the brittleness of the material increases, and at the same time, due to the lack of the action of the soft segment component of the toughening agent, the anti-abnormal noise effect of the material also becomes worse, manifested as an increase in RPN and human ear loudness.

[0063] From the comparative analysis of Example 2 and Comparative Example 2, it can be seen that when other component toughening agents (not recommended by the present invention) are added, the anti-abnormal noise effect of the material is not good, and the RPN and human ear loudness are on the high side.

[0064] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which does not affect the essence of the present invention.

Claims

1. A sound-proof polycarbonate material, characterized in that, the sound-proof polycarbonate material comprises the following components in parts by weight: 100 parts of polycarbonate, 20 - 40 parts of hindered phenol, 2 - 5 parts of toughening agent, 0.1 - 2 parts of antioxidant, 0.5 - 2 parts of lubricant; the hindered phenol is one or more of AO300, AO80, AO60; the toughening agent is one or several of methyl methacrylate - butadiene - styrene terpolymer, ethylene - acrylate copolymer.

2. The sound-proof polycarbonate material according to claim 1, characterized in that, the sound-proof polycarbonate material comprises the following components in parts by weight: 100 parts of polycarbonate, 20 - 40 parts of hindered phenol, 3 - 5 parts of toughening agent, 0.1 - 1 part of antioxidant, 0.5 - 1.5 parts of lubricant.

3. The sound-proof polycarbonate material according to claim 1, characterized in that, the polycarbonate is bisphenol A polycarbonate resin, and the mass melt flow rate under the test conditions of 300 °C and 1.2 kg is 10 - 20 g / 10min.

4. The sound-proof polycarbonate material according to claim 1, characterized in that, the antioxidant is one or several of pentaerythritol tetra[β-(3,5 - di - tert - butyl - 4 - hydroxyphenyl)propionate], n - octadecyl 3-(3,5 - di - tert - butyl - 4 - hydroxyphenyl)propionate, triphenyl phosphite tris(2,4 - di - tert - butyl), bis(pentaerythritol diphosphite) distearyl.

5. The sound-proof polycarbonate material according to claim 1, characterized in that, the lubricant is one or several of silicone oil, silicone powder, paraffin wax, stearic acid, butyl stearate, oleamide, ethylene bisstearamide.

6. A preparation method of the sound-proof polycarbonate material according to claim 1, characterized in that, the preparation method specifically comprises the following steps: (1)Prepare materials for each component according to the following parts by weight: 100 parts of polycarbonate PC, 20 - 40 parts of hindered phenol, 2 - 5 parts of toughening agent, 0.1 - 2 parts of antioxidant, 0.5 - 2 parts of lubricant; (2)For the materials prepared in step (1), mix them evenly in a high-speed mixer, add the evenly mixed materials into a twin-screw extruder for melt blending and extrusion, and extrude and pelletize to obtain the sound-proof polycarbonate material.

7. The preparation method according to claim 6, characterized in that, in step (2), the extrusion temperature is 180 - 250 °C, and the screw speed is 200 - 500 rpm.

8. The preparation method according to claim 6, characterized in that, in step (2), the rotation speed of the high-speed mixer is 100 - 300 r / min, and the mixing time is 10 - 30 min.

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