Polycarbonate / polyethylene glycol terephthalate alloy material as well as preparation method and application thereof

Abstract

The invention relates to a polycarbonate / polyethylene glycol terephthalate alloy material as well as a preparation method and application thereof, and belongs to the technical field of compositions of high-molecular compounds. The polycarbonate / polyethylene glycol terephthalate alloy material is prepared from the following components in parts by weight: 50 to 60 parts of PC (polycarbonate) resin, 20 to 30 parts of PET (polyethylene glycol terephthalate) resin and 10 to 20 parts of talcum powder, the terminal carboxyl group content of the PET resin is less than or equal to 42 mol / t; the pH value of the talcum powder is less than or equal to 9 and a / b is more than or equal to 4 and less than or equal to 7. The polycarbonate / polyethylene glycol terephthalate alloy material has excellent dimensional stability and good appearance performance.

Description

Technical Field

[0001] This invention relates to the field of polymer composition technology, and more particularly to a polycarbonate / polyethylene terephthalate alloy material, its preparation method, and its application. Background Technology

[0002] Polycarbonate (PC) possesses excellent mechanical toughness, heat resistance, and flame retardancy, but its chemical solvent resistance and processing performance are relatively poor. Polyethylene terephthalate (PET), as a crystalline material, exhibits good mechanical strength, high chemical stability, and ease of polishing. Therefore, PC and PET are often combined to create PC / PET alloys, which combine the advantages of both. However, in practical applications, it has been found that PC / PET alloys have high molding shrinkage and poor heat stability, resulting in insufficient dimensional accuracy of the manufactured parts, making them unsuitable for large-sized, complex structures and parts subject to thermal cycling. Currently, this is mainly addressed by adding large amounts of rigid materials. For example, glass fiber or talc is used for modification. However, due to the significant polarity difference between glass fiber and the resin matrix, while improving the stability of the PC / PET alloy, it also leads to surface fiber shedding and a decrease in impact toughness. While talc does not cause surface fiber shedding, it produces appearance defects such as silver streaks and material inclusions, and also results in lower impact strength and poor thermal stability. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a polycarbonate / polyethylene terephthalate alloy material, its preparation method, and its application.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a polycarbonate / polyethylene terephthalate alloy material, comprising the following components by weight: 50-60 parts PC resin, 20-30 parts PET resin, 10-20 parts talc; The end carboxyl group content of the PET resin is ≤42mol / t; The talc powder has a pH ≤ 9 and satisfies 4 ≤ a / b ≤ 7, where a is the maximum length between two arbitrary points on the outer circumference of the talc powder projection image, and b is the minimum distance between two straight lines on the outer circumference of the talc powder projection image, which are in contact with the projection image and parallel to the straight line connecting the two points used to determine the maximum length a.

[0005] This invention combines talc powder with a specific aspect ratio to PC resin and PET resin with a specific end-carboxyl group content. While ensuring that the ester bonds of PC and PET resins are not excessively hydrolyzed during high-temperature processing, the talc powder with a specific size structure is uniformly dispersed in the resin matrix and oriented to form a brick-and-mortar-like structure during melt processing. This reduces stress concentration and better transmits stress, thereby improving the mechanical properties of the PC / PET alloy material. The talc powder with a specific size structure also hinders the chain relaxation of PC or PET molecular chains at high temperatures, improving the heat resistance of the PC / PET alloy material. Furthermore, the talc powder oriented along the flow direction can act as anisotropic initiation points, promoting the orientation of PET molecular chains to a certain extent, thus improving the dimensional stability of the PC / PET alloy material under thermal cycling. Simultaneously, compared to other talc powders, the lower alkalinity of the talc powder can reduce appearance defects in the PC / PET alloy material during injection molding, thereby improving the appearance performance of the PC / PET alloy material.

[0006] Furthermore, talc with an excessively high a / b ratio tends to be over-oriented in the resin melt, resulting in a lack of reinforcement in the vertical direction. This makes the PC / PET alloy material prone to warping and deformation after thermal cycling. On the other hand, talc with an excessively low a / b ratio has a weaker ability to suppress the thermal expansion of the PC / PET alloy material and a weaker effect on the heterogeneous nucleation of PET. It also cannot effectively orient itself along the mold wall, resulting in poor dimensional stability and appearance of the PC / PET alloy material under thermal cycling.

[0007] Based on the total mass of the polycarbonate / polyethylene terephthalate alloy material, the total mass content of PC resin and PET resin is ≥70%, and the mass content of PC resin is ≥45%.

[0008] In some embodiments, the weight parts of PC resin in the polycarbonate / polyethylene terephthalate alloy material may be, but are not limited to, any one or any two of the following values: 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, and 60 parts.

[0009] In some embodiments, the weight parts of PET resin in the polycarbonate / polyethylene terephthalate alloy material may be, but are not limited to, any one or any two of the following values: 20 parts, 21 parts, 22 parts, 33 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, and 30 parts.

[0010] In some embodiments, the weight percentage of talc in the polycarbonate / polyethylene terephthalate alloy material may be, but is not limited to, any one or both of the following values: 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, and 20 parts.

[0011] In some embodiments, the end carboxyl group content of the PET resin may be, but is not limited to, any one or any two of the following values: 42 mol / t, 41 mol / t, 40 mol / t, 39 mol / t, 38 mol / t, 37 mol / t, 36 mol / t, 35 mol / t, 34 mol / t, 33 mol / t, 32 mol / t, 31 mol / t, 30 mol / t, 29 mol / t, 28 mol / t, 27 mol / t, 26 mol / t, 25 mol / t, 24 mol / t, 23 mol / t, 22 mol / t, 21 mol / t, and 20 mol / t.

[0012] In some embodiments, the pH of the talc may be, but is not limited to, a range of any one or both of the following: 9, 8.8, 8.6, 8.4, 8.2, 8, 7.8, 7.6, 7.4, 7.2, 7, 6.8, 6.6, 6.4, 6.2, 6.

[0013] In some implementations, the aspect ratio a / b of the talc powder may be, but is not limited to, any or both of the following values: 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, 5.8, 6, 6.2, 6.4, 6.6, 6.8, 7.

[0014] The end carboxyl group content of PET resin can be determined by acid-base titration, with phenol / chloroform (volume ratio 2:3) as the test solvent.

[0015] The pH of talc can be measured by the following method: Weigh 30g of talc into a polytetrafluoroethylene beaker, pour in 100mL of deionized water, stir magnetically at 80℃ for 60min, stop stirring, cool to 25℃ and filter, and use a pH meter to test the pH value of the filtrate, which is the pH value of the talc.

[0016] The aspect ratio a / b of talc can be measured with reference to existing technology. Specifically, it is based on the Coulter principle and includes the following steps: a flash lamp generates a voltage pulse when the talc particles pass through the micropores, which captures the projected image of the particles, and the projected image is analyzed; where a is the maximum length between two arbitrary points on the outer circumference of the projected image of the talc, and b is the minimum distance between two straight lines on the outer circumference of the projected image of the talc, which are in contact with the projected image and parallel to the straight line connecting the two points used to determine the maximum length a.

[0017] In a preferred embodiment of the polycarbonate / polyethylene terephthalate alloy material of the present invention, the talc powder satisfies: 4.2≤a / b≤6.7.

[0018] As a preferred embodiment of the polycarbonate / polyethylene terephthalate alloy material of the present invention, the melt mass flow rate of the PC resin at 300°C and 1.2 kg (test standard is ISO 1133-2012) is 10 g / 10 min to 25 g / 10 min, for example, but not limited to any one or any two of the following values: 10 g / 10 min, 11 g / 10 min, 12 g / 10 min, 13 g / 10 min, 14 g / 10 min, 15 g / 10 min, 16 g / 10 min, 17 g / 10 min, 18 g / 10 min, 19 g / 10 min, 20 g / 10 min, 21 g / 10 min, 22 g / 10 min, 23 g / 10 min, 24 g / 10 min, and 25 g / 10 min.

[0019] In some embodiments, the PC resin is preferably bisphenol A polycarbonate.

[0020] In a preferred embodiment of the polycarbonate / polyethylene terephthalate alloy material of the present invention, the intrinsic viscosity of the PET resin is from 0.6 dL / g to 1 dL / g, for example, but not limited to any one or both of 0.6 dL / g, 0.65 dL / g, 0.7 dL / g, 0.75 dL / g, 0.8 dL / g, 0.85 dL / g, 0.9 dL / g, 0.95 dL / g, and 1 dL / g. The intrinsic viscosity of the PET resin can be determined using the standard ASTM D4603-2011.

[0021] In a preferred embodiment of the polycarbonate / polyethylene terephthalate alloy material of the present invention, the end carboxyl group content of the PET resin is 20 mol / t to 40 mol / t.

[0022] As a preferred embodiment of the polycarbonate / polyethylene terephthalate alloy material of the present invention, the particle size D of the talc powder is... 50 The particle size is from 4 μm to 7 μm, for example, it can be, but is not limited to, any or both of the following values: 4 μm, 4.2 μm, 4.4 μm, 4.6 μm, 4.8 μm, 5 μm, 5.2 μm, 5.4 μm, 5.6 μm, 5.8 μm, 6 μm, 6.2 μm, 6.4 μm, 6.6 μm, 6.8 μm, 7 μm. The particle size D of talc is... 50 It can be determined using a particle size analyzer (sedimentation method).

[0023] As a preferred embodiment of the polycarbonate / polyethylene terephthalate alloy material of the present invention, the pH of the talc is 8 to 8.7, for example, it can be, but is not limited to, any one or any two of 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7.

[0024] As a preferred embodiment of the polycarbonate / polyethylene terephthalate alloy material of the present invention, the polycarbonate / polyethylene terephthalate alloy material further includes 0.1 to 5 parts by weight of processing aids.

[0025] In a preferred embodiment of the polycarbonate / polyethylene terephthalate alloy material of the present invention, the processing aid includes at least one of antioxidant, lubricant, and compatibilizer.

[0026] In some embodiments, the antioxidant is 0.1 to 0.4 parts by weight, and may be, but is not limited to, at least one of hindered phenolic antioxidants and phosphite antioxidants.

[0027] In some embodiments, the lubricant is 0.3 to 0.6 parts by weight, and may be, but is not limited to, at least one of silicone lubricants, ester or phosphate lubricants, and organosilicon lubricants.

[0028] In some embodiments, the compatibilizer is 2 to 5 parts by weight, and may be, but is not limited to, ethylene acrylates.

[0029] Secondly, the present invention provides a method for preparing the above-mentioned polycarbonate / polyethylene terephthalate alloy material, comprising the following steps: mixing each component evenly and then melting and extruding to obtain the polycarbonate / polyethylene terephthalate alloy material.

[0030] In some embodiments, the above preparation method can use a twin-screw extruder for melt extrusion, with the screw temperature of the twin-screw extruder controlled between 80°C and 270°C, the length-to-diameter ratio of the twin-screw extruder between 38:1 and 50:1, and the screw speed between 200 and 400 rpm.

[0031] Thirdly, this invention provides an application of the above-mentioned polycarbonate / polyethylene terephthalate alloy material in the manufacture of automotive parts, electronic and electrical components, and sporting goods. For example, automotive parts may include, but are not limited to, spoilers, lidar covers, electric rear wings, and roof trim panels.

[0032] Fourthly, the present invention provides an automotive component made of the aforementioned polycarbonate / polyethylene terephthalate alloy material.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention combines talc powder with a specific aspect ratio to PC resin and PET resin with a specific end-carboxyl group content. While ensuring that the ester bonds of PC and PET resins are not excessively hydrolyzed during high-temperature processing, the talc powder with a specific size structure is uniformly dispersed in the resin matrix and oriented to form a brick-and-mortar-like structure during melt processing. This reduces stress concentration and better transmits stress, thereby improving the mechanical properties of the PC / PET alloy material. The talc powder with a specific size structure also hinders the chain relaxation of PC or PET molecular chains at high temperatures, improving the heat resistance of the PC / PET alloy material. Furthermore, the talc powder oriented along the flow direction can act as anisotropic initiation points, promoting the orientation of PET molecular chains to a certain extent, thus improving the dimensional stability of the PC / PET alloy material under thermal cycling. Simultaneously, compared to other talc powders, the lower alkalinity of the talc powder can reduce appearance defects in the PC / PET alloy material during injection molding, thereby improving the appearance performance of the PC / PET alloy material. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of "a" and "b" of the talc powder of the present invention. Detailed Implementation

[0035] 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 embodiments.

[0036] Unless otherwise specified, all other materials, reagents, etc. used in the examples and comparative examples are commercially available.

[0037] 1. Raw materials and reagents 1) PC resin PC resin 1, melt flow rate of 19 g / 10 min (300℃ / 1.2 kg), grade PCH-2000F, manufacturer Mitsubishi Chemical; PC resin 2, melt flow rate of 11g / 10min (300℃ / 1.2kg), grade PC 2100, manufacturer Wanhua Chemical.

[0038] 2) PET resin PET resin 1, with end carboxyl group content of 21 mol / t, intrinsic viscosity of 0.9 dL / g, grade PET BG85, manufacturer Sinopec Yizheng; PET resin 2, with a terminal carboxyl group content of 22 mol / t, an intrinsic viscosity of 0.78 dL / g, grade PETBG801, manufactured by Sinopec Yizheng. PET resin 3, end carboxyl group content is 27mol / t, intrinsic viscosity is 0.8dL / g, grade PET BG80, manufacturer is Sinopec Yizheng; PET resin 4, end carboxyl group content is 52mol / t, intrinsic viscosity is 0.675dL / g, grade PET SB500, manufacturer is Dongcai Technology.

[0039] 3) Talc or wollastonite Talc 1, pH=8.7, particle size D 50 =6.2μm, a / b=6.7, grade Steamic T1CN, manufacturer Yirui Stone; Talc 2, pH=8.5, particle size D 50 =5.4μm, a / b=4.2, grade Finntalc M05SLC, manufacturer Xingbeida Chemical Materials Co., Ltd.; Talc 3, pH=9.5, particle size D 50 =6.8μm, a / b=3.8, grade TYT-777A, manufacturer Haicheng Tianyuan; Talc powder 4 is obtained by surface treatment of talc powder 3 as follows: 100 mL of glacial acetic acid is weighed and placed in a polytetrafluoroethylene beaker, water is added to adjust the pH of the solution to 5.0, 20 g of talc powder is weighed and placed in the polytetrafluoroethylene beaker for soaking, filtered, and the talc powder is placed in an 80℃ oven for 120 min to obtain talc powder 4 (pH 8.5).

[0040] Talc 5, pH=9.3, particle size D 50 =0.65μm, a / b=3.0, grade HTP Ultra5L, manufacturer: Liaoning Aihaiyimi; Wollastonite, pH=9.0, particle size D 50 =6.8μm, a / b=9.0, grade M4W, manufacturer Yirui Stone; In the above "a / b", 'a' represents the maximum length between two arbitrary points on the outer circumference of the projected image of talc (or wollastonite), and 'b' represents the minimum distance between two straight lines on the outer circumference of the projected image of talc (or wollastonite), which are in contact with the projected image and parallel to the straight line connecting the two points used to determine the maximum length 'a' (e.g., ...). Figure 1 (As shown).

[0041] 4) The processing aid consists of antioxidants and lubricants in a 1:1 mass ratio; The antioxidant is a compound of antioxidant 1010 (commercially available) and antioxidant 412S (commercially available) in a mass ratio of 1:2; the lubricant is pentaerythritol stearate (commercially available).

[0042] 2. Preparation method of polycarbonate / polyethylene terephthalate alloy material of the present invention According to the formula, the components are mixed evenly and then added to a twin-screw extruder for melt extrusion and granulation to obtain a polycarbonate / polyethylene terephthalate alloy material. The temperature of the twin-screw extruder is as follows: Zone 1: 90℃; Zone 2: 120℃; Zone 3: 250℃; Zone 4: 230℃; Zone 5: 230℃; Zone 6: 235℃; Zone 7: 235℃; Zone 8: 230℃; Zone 9: 250℃; and the die head temperature is 250℃. The screw speed is 500 rpm.

[0043] Table 1 shows the weight parts of each component in the polycarbonate / polyethylene terephthalate alloy materials in each embodiment. Table 2 shows the weight parts of each component in the polycarbonate / polyethylene terephthalate alloy materials in each embodiment. 3. Performance Testing 1) Flexural modulus: Tested according to ISO 178:2019, injection molded into a standard specimen, with a bending rate of 2 mm / min.

[0044] 2) Notched impact strength of simply supported beam: Tested according to ISO 179-1:2023, injection molded into a standard specimen (notch type 1eA), pendulum energy is 4J.

[0045] 3) Heat distortion temperature (1.8MPa): Tested according to ISO 75-2:2013, the heating rate is 120℃ / h.

[0046] 4) Coefficient of linear expansion: Tested according to ISO 11359-2:2021, the temperature range is 23~85℃.

[0047] 5) Appearance evaluation: A sample of 356mm×10mm×3mm size was injection molded at 270℃ and heat-treated for 10 minutes. Then, the sample was photographed using photography software and the total amount of material spots / silver threads on the sample surface was counted using statistical software. The area ratio of material spots / silver threads was less than 5% as Grade 1, 5%~10% as Grade 2, 10%~30% as Grade 3, 30%~50% as Grade 4, and more than 50% as Grade 5.

[0048] Table 3. Performance of polycarbonate / polyethylene terephthalate alloy materials in each example and comparative example. According to the data in Table 3, the linear expansion coefficients of the polycarbonate / polyethylene terephthalate alloy materials in Examples 1 to 7 are all less than or equal to 65, and their appearance grades are all below grade 3. Simultaneously, their flexural modulus reaches 3770 MPa to 5150 MPa, and their notched impact strength reaches 4.6 kJ / m². 2 Up to 10 kJ / m 2 The heat distortion temperature reaches 103°C to 105°C, indicating that the polycarbonate / polyethylene terephthalate alloy material of the present invention not only has excellent heat resistance and dimensional stability, but also good mechanical properties and appearance properties.

[0049] According to Examples 1, 1, 3, and 4, the pH and aspect ratio a / b of talc have a significant impact on the performance of polycarbonate / polyethylene terephthalate alloy materials. If the pH of talc is too high or the aspect ratio is too small, it is difficult to improve the dimensional stability and appearance of polycarbonate / polyethylene terephthalate alloy materials at the same time. According to Comparative Example 2, it can also be found that when the end carboxyl group content of PET resin is too high, although it has little impact on the dimensional stability of polycarbonate / polyethylene terephthalate alloy materials, it will significantly deteriorate their appearance.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polycarbonate / polyethylene terephthalate alloy material, characterized in that, By weight, it includes the following components: 50-60 parts PC resin, 20-30 parts PET resin, 10-20 parts talc; The end carboxyl group content of the PET resin is ≤42mol / t; The talc powder has a pH ≤ 9 and satisfies 4 ≤ a / b ≤ 7, where a is the maximum length between two arbitrary points on the outer circumference of the talc powder projection image, and b is the minimum distance between two straight lines on the outer circumference of the talc powder projection image, which are in contact with the projection image and parallel to the straight line connecting the two points used to determine the maximum length a.

2. The polycarbonate / polyethylene terephthalate alloy material as described in claim 1, characterized in that, The talc powder satisfies: 4.2≤a / b≤6.

7.

3. The polycarbonate / polyethylene terephthalate alloy material as described in claim 1, characterized in that, The PC resin has a melt flow rate of 10 g / 10 min to 25 g / 10 min at 300 °C and 1.2 kg, and / or the PET resin has an intrinsic viscosity of 0.6 dL / g to 1 dL / g.

4. The polycarbonate / polyethylene terephthalate alloy material as described in claim 1, characterized in that, The PET resin has a terminal carboxyl group content of 20 mol / t to 40 mol / t.

5. The polycarbonate / polyethylene terephthalate alloy material as described in claim 1, characterized in that, The particle size D of the talc powder 50 The talc has a particle size of 4 μm to 7 μm and / or the pH of the talc is 8 to 8.

7.

6. The polycarbonate / polyethylene terephthalate alloy material as described in claim 1, characterized in that, The polycarbonate / polyethylene terephthalate alloy material also includes 0.1 to 5 parts by weight of processing aids.

7. The polycarbonate / polyethylene terephthalate alloy material as described in claim 6, characterized in that, The processing aids include at least one of antioxidants, lubricants, and compatibilizers.

8. A method for preparing the polycarbonate / polyethylene terephthalate alloy material according to any one of claims 1 to 7, characterized in that, The process includes the following steps: mixing the components evenly and then melting and extruding them to obtain a polycarbonate / polyethylene terephthalate alloy material.

9. The application of the polycarbonate / polyethylene terephthalate alloy material according to any one of claims 1 to 7 in the manufacture of automotive parts, electronic and electrical parts, and sporting goods.

10. An automotive component, characterized in that, Made from the polycarbonate / polyethylene terephthalate alloy material as described in any one of claims 1 to 7.

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