Microwave-cured surface-hardened pc alloy and method of making

Abstract

The application provides a microwave-cured surface-hardened PC alloy and a preparation method. The PC alloy contains a methacrylate monomer and an epoxy chain extender. The methacrylate monomer migrates to the surface of the PC under high-temperature injection molding, and is crosslinked with the epoxy chain extender through microwave irradiation and the action of a catalyst, thereby significantly improving the surface hardness of the PC alloy. The methacrylate liquid is injected from the middle section of an extruder, and the epoxy chain extender is injected from the end section of the extruder, so that the microwave-cured surface-hardened PC alloy is prepared through melt extrusion. The alloy material can efficiently improve the surface hardness of the PC resin, and does not affect the original performance of the resin.

Description

Technical Field

[0001] This invention belongs to the field of PC alloy plastics, and particularly relates to a microwave-cured surface-hardened PC alloy and its preparation method. Background Technology

[0002] Polycarbonate (PC) is a widely used engineering plastic, applied in fields such as 3C (computers, communications, and consumer electronics), wall panels, home appliances, and automotive interiors. However, PC resin itself has relatively low surface hardness, making it prone to scratches and marks during production, transportation, and use. Therefore, research on improving the surface hardness of PC resin is crucial. Commercially available general-purpose polycarbonate pencils typically have a hardness around 3B. Currently, the industry mainly uses two methods to improve the hardness of PC products: one is spray painting, which involves complex processes, significant pollution, and high costs; the other is blending with polymethyl methacrylate (PMMA), but this method offers limited hardness improvement, and high PMMA content can severely impact the flame retardant properties and toughness of PC products.

[0003] Currently, improving the surface hardness of PC mainly involves adding scratch-resistant agents and blending with polymethyl methacrylate (PMMA). Patent CN101812225A discloses a flame-retardant polycarbonate material with high surface hardness and gloss, and its preparation method. This method improves the surface hardness of the material by adding a high content of PMMA, with a polycarbonate to PMMA ratio of 4:1. This significantly affects the rigidity and toughness of the polycarbonate material, making it difficult to achieve industrialization and production applications.

[0004] In summary, there is an urgent need to solve the problem of efficiently improving the surface hardness of PC resin without affecting its original properties. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, one of the objectives of the present invention is to provide a PC alloy material that can effectively improve the surface hardness of PC resin without affecting the original properties of the resin.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0007] A PC alloy material, wherein the raw materials of the PC alloy material comprise the following components in parts by weight:

[0008]

[0009]

[0010] PC resin itself has relatively low hardness. Existing hardening technologies mainly fall into two categories: one is applying a hardening coating, and the other is adding a high proportion of high-hardness resin. However, these methods suffer from problems such as cumbersome processes, significant pollution, and negative impacts on the performance of the PC substrate. The inventors discovered that this problem can be solved in two ways: firstly, by adding methacrylate, which migrates to the finished product surface during high-temperature injection molding, reducing its impact on the PC substrate's performance; secondly, by using microwaves, cross-linking occurs on the product surface with epoxy chain extenders, significantly increasing hardness. This achieves high surface hardness in PC products without affecting the original mechanical and thermal properties of the PC resin.

[0011] In one embodiment of the present invention, the PC resin is one or more of aromatic polycarbonate, aliphatic polycarbonate, and aromatic-aliphatic polycarbonate, preferably bisphenol A type polycarbonate, and more preferably one or more of Wanhua Chemical 2070, 2100, 2150, 2220, and 2350. For example, the polycarbonate, under test conditions of 300°C and a load of 1.2 kg, is required to have a melt flow index (MFR) between 5 and 50 g / 10 min, preferably between 10 and 30 g / 10 min.

[0012] In one embodiment of the present invention, the epoxy chain extender is an organic compound with 8-20 epoxy functional groups, preferably a copolymer of styrene-methyl methacrylate-glycidyl methacrylate, and more preferably one or more of chain extenders ADR4468, ADR4370, and ADR4400.

[0013] In one embodiment of the present invention, the catalyst is one or more of bis(boron trifluoride)bis(diphenyl)cobalt oxime, bis(boron trifluoride)bis(dimethyl)cobalt oxime, and bis(boron trifluoride)bis(dicyclohexyl)cobalt oxime.

[0014] This invention also includes adjuvants known in the art, such as antioxidants, in a content of 0.1-1 parts, preferably 0.2-0.5 parts; the antioxidants may be one or more combinations of hindered phenols, benzofurans, acryloyl-modified phenols, and hydroxylamines; preferably one or more of hindered phenols; more preferably one or more of BASF's antioxidants Irganox 1076, Irganox 1010, and Irganox 168. The antioxidants and other adjuvants and their amounts are known in the art.

[0015] In one embodiment of the present invention, the methacrylate is liquid α-methacrylate and / or ethyl methacrylate, preferably liquid α-methacrylate with a purity ≥99.5%.

[0016] Another object of the present invention is to provide a method for preparing PC alloy materials.

[0017] A method for preparing a PC alloy material, wherein the material is the aforementioned PC alloy material, and the preparation method comprises the following steps:

[0018] S1: After the catalyst, PC resin and additives are mixed, the mixture is fed into the main feeder of the extruder;

[0019] S2: Add methacrylate from the middle section of the extruder feedstock;

[0020] S3: Add the epoxy chain extender from the end feed section of the extruder;

[0021] S4: Melt, extrude, and granulate to obtain PC alloy material granules.

[0022] For example, the above preparation process may involve the following reactions:

[0023]

[0024] In one embodiment of the present invention, the catalyst, PC resin and additives in S1 are mixed using a high-speed mixer, preferably with a mixing speed of 300-900 rpm and a mixing time of 100-400 s.

[0025] In one embodiment of the present invention, the middle section of S2 is the third-fourth section of the extruder barrel.

[0026] In one embodiment of the present invention, the last section of S3 is the 6th-7th barrel section of the extruder.

[0027] In one embodiment of the present invention, the extrusion temperature of S4 is 250-300℃ and the screw speed is 300-800rpm; preferably, the extrusion temperature is set in segments from the feed port to the die head as follows: 250-260℃ at the feed port, 280-300℃ for each of the first to fourth segments, and 250-280℃ for each of the fifth to seventh segments.

[0028] In this invention, for example, the vacuum level of the twin-screw metering section vacuum device can be controlled to be less than -0.8 bar, and the cooling water tank temperature to be 30-80°C. The process described is a commonly used control process in this field.

[0029] Another object of the present invention is to provide an application of PC alloy material.

[0030] An application of a PC alloy material, wherein the material is the PC alloy material described above, or a PC alloy material prepared by the above preparation method, and the material is used in electronic and electrical appliances, home appliances, and digital products.

[0031] Another object of the present invention is to provide a method for preparing PC articles.

[0032] A method for preparing PC articles, wherein the articles are made of the PC alloy material described above, or PC alloy material prepared by the above preparation method, the method comprising: after obtaining the articles by injection molding, microwave curing is performed; preferably, the injection molding machine barrel temperature is set to 300-320℃, the injection pressure to 60-80MPaG, the mold temperature to 110-130℃, and the holding time to 1-3s; preferably, the microwave curing power is 100-500W, the irradiation temperature is 80-100℃, and the irradiation time is 1-3min.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] (1) The hardness is greatly increased to 2H-3H.

[0035] (2) It does not affect the original mechanical and thermal properties of PC resin. Detailed Implementation

[0036] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0037] I. The main sources of raw materials in the examples and comparative examples are shown in Table 1 below:

[0038] Table 1 Raw Material Source Information

[0039]

[0040]

[0041] Unless otherwise specified, all other raw materials and reagents were obtained through commercially available channels.

[0042] II. The performance test parameters and corresponding test methods for the PC alloy in the examples and comparative examples are as follows:

[0043] The processing equipment used was: a twin-screw extruder, KraussMaffei ZE28 x40D BD, with a length-to-diameter ratio of 40 and a screw diameter of 28cm;

[0044] The performance test parameters and corresponding test methods for PC alloy are as follows:

[0045] Pencil hardness: GB 6739—86 "Coating Hardness - Pencil Hardness Method" was adopted;

[0046] Flexural strength and modulus (MPa): conformed to ISO 178:2010 "Plastics - Determination of flexural properties";

[0047] Impact strength (MPa): Tested according to ISO 180-2000 "Plastics - Determination of Izod impact strength";

[0048] Heat distortion temperature (°C): Tested according to ISO 75 / B "Plastics - Test method for heat distortion temperature".

[0049] Example 1

[0050] Microwave-cured surface-hardened PC alloys were prepared using the following raw material formulation:

[0051]

[0052] The preparation method is as follows:

[0053] a. Mix the catalyst, PC resin, and antioxidant in a high-speed mixer at a speed of 600 rpm for 200 seconds.

[0054] b. Feed the mixture from step a) into the main feeder of the extruder;

[0055] c. Add α-methacrylate liquid from the side-feeding 3-section barrel;

[0056] d. Add epoxy chain extender ADR4468 from the feed port of the last 6th section of the barrel;

[0057] e. Extrusion conditions are as follows: control the vacuum degree of the vacuum device in the metering section of the twin screw to be less than 0.08MPa, the screw speed to be 500rpm, and the screw temperature from the feed port to the die head is set in segments as follows: 255℃, 290℃, 290℃, 290℃, 265℃, 265℃, 265℃.

[0058] f. Cool the extruded material in the extruder water tank at 50°C and then pelletize it;

[0059] g. Inject the particles from step f) into a sample under the conditions of injection temperature 300℃, injection pressure 60Mpa, mold temperature 110℃, and holding pressure 1s.

[0060] h. Place the sample from step g) under microwave power of 100W and temperature of 80℃ for 1 minute to obtain a surface-hardened PC alloy.

[0061] Example 2

[0062] Microwave-cured surface-hardened PC alloys were prepared using the following raw material formulation:

[0063]

[0064] The preparation method is as follows:

[0065] a. Mix the catalyst, PC resin, and antioxidant in a high-speed mixer at a speed of 300 rpm for 400 seconds.

[0066] b. Feed the mixture from step a) into the main feeder of the extruder;

[0067] c. Add α-methacrylate liquid from the side-feeding 4-section barrel;

[0068] d. Add epoxy chain extender ADR4370 from the feed port of the last 7th section of the barrel;

[0069] e. Extrusion conditions are as follows: control the vacuum degree of the vacuum device in the metering section of the twin screw to be less than 0.08MPa, the screw speed to be 300rpm, and the screw temperature from the feed port to the die head is set in segments as follows: 250℃, 280℃, 280℃, 280℃, 250℃, 250℃, 250℃.

[0070] f. Cool the extruded material in the extruder water tank at 80°C and then pelletize it;

[0071] g. Inject the particles from step f) into a sample under the conditions of injection temperature 320℃, injection pressure 80Mpa, mold temperature 130℃, and holding pressure 3s.

[0072] h. Place the sample from step g) under microwave power of 500W and temperature of 100℃ for 3 minutes to obtain a surface-hardened PC alloy.

[0073] Example 3

[0074] Microwave-cured surface-hardened PC alloys were prepared using the following raw material formulation:

[0075]

[0076] The preparation method is as follows:

[0077] a. Mix the catalyst, PC resin, and antioxidant in a high-speed mixer at a speed of 900 rpm for 100 seconds.

[0078] b. Feed the mixture from step a) into the main feeder of the extruder;

[0079] c. Add α-methacrylate liquid from the side-feeding 3-section barrel;

[0080] d. Add epoxy chain extender ADR4400 from the feed port of the last 7th section of the barrel;

[0081] e. Extrusion conditions are as follows: control the vacuum degree of the vacuum device in the metering section of the twin screw to be less than 0.08MPa, the screw speed to be 800rpm, and the screw temperature from the feed port to the die head is set in segments as follows: 260℃, 300℃, 300℃, 300℃, 280℃, 280℃, 280℃.

[0082] f. Cool the extruded material in the extruder water tank at 30°C and then pelletize it;

[0083] g. Inject the particles from step f) into a sample under the conditions of injection temperature 310℃, injection pressure 70Mpa, mold temperature 120℃, and holding pressure 2s.

[0084] h. Place the sample from step g) under microwave power of 300W and temperature of 90℃ for 2 minutes to obtain a surface-hardened PC alloy.

[0085] Comparative Example 1

[0086] Compared with Example 1, the only difference is that no epoxy chain extender is added.

[0087] Comparative Example 2

[0088] Compared with Example 1, the only difference is that no liquid methacrylate is added.

[0089] Comparative Example 3

[0090] Compared with Example 1, the only difference is that no methacrylate liquid and epoxy chain extender are added.

[0091] Comparative Example 4

[0092] Compared with Example 1, the only difference is that α-methacrylate liquid is not added and is replaced with the same mass of polymethyl methacrylate resin HD01.

[0093] The relevant properties of the PC alloys obtained in Examples 1-3 and Comparative Examples 1-4 are shown in Table 2.

[0094] Table 2. Performance test results of products in Examples 1-3 (S1-S3) and Comparative Examples 1-4 (D1-D4)

[0095]

[0096]

[0097] As can be seen from Comparative Examples 1-4 and Examples 1-3, the PC alloys in the examples have higher surface hardness, and the mechanical and thermal properties of the PC alloys are well maintained. In contrast, the comparative examples exhibit disadvantages such as low toughness, reduced strength, and decreased heat resistance.

[0098] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A PC alloy material, characterized in that, The raw materials of the PC alloy material contain the following components in parts by weight: 86-98 parts of PC resin, 0.5-2 parts epoxy chain extender Catalyst 0.1-1 part, 2-10 parts of methacrylate; The PC alloy material is microwave cured after injection molding to obtain the product.

2. The material according to claim 1, characterized in that, The raw materials of the PC alloy material contain the following components in parts by weight: 90-95 parts of PC resin, 1-1.5 parts epoxy chain extender Catalyst 0.4-0.6 parts, 5-10 parts of methacrylate.

3. The material according to claim 1, characterized in that, The PC resin is one or more of aromatic polycarbonate, aliphatic polycarbonate, and aromatic-aliphatic polycarbonate.

4. The material according to claim 3, characterized in that, The PC resin is bisphenol A type polycarbonate.

5. The material according to claim 1, characterized in that, The PC resin is one or more of Wanhua Chemical's 2070, 2100, 2150, 2220, and 2350.

6. The material according to claim 1 or 2, characterized in that, The epoxy chain extender is an organic compound with 8-20 epoxy functional groups.

7. The material according to claim 6, characterized in that, The epoxy chain extender is a copolymer of styrene-methyl methacrylate-glycidyl methacrylate.

8. The material according to claim 7, characterized in that, The epoxy chain extender is one or more of chain extenders ADR4468, ADR4370, and ADR4400.

9. The material according to claim 1, characterized in that, The catalyst is one or more of bis(boron trifluoride)bis(diphenyl)cobalt oxime, bis(boron trifluoride)bis(dimethyl)cobalt oxime, and bis(boron trifluoride)bis(dicyclohexyl)cobalt oxime.

10. The material according to claim 1, characterized in that, The methacrylate is liquid α-methacrylate and / or ethyl methacrylate.

11. The material according to claim 10, characterized in that, The methacrylate is a liquid α-methacrylate with a purity of ≥99.5%.

12. A method for preparing a PC alloy material, wherein the material is the PC alloy material according to any one of claims 1-11, characterized in that, The preparation method includes the following steps: S1: After the catalyst, PC resin and additives are mixed, the mixture is fed into the main feeder of the extruder; S2: Add methacrylate from the middle section of the extruder feedstock; S3: Add the epoxy chain extender from the end feed section of the extruder; S4: Melt, extrude, and granulate to obtain PC alloy material granules.

13. The preparation method according to claim 12, characterized in that, The catalyst, PC resin, and additives in S1 are mixed using a high-speed mixer; And / or, the middle section of S2 is the 3rd-4th barrel section of the extruder; And / or, the last section of S3 is the 6th-7th barrel section of the extruder; And / or, the extrusion temperature of S4 is 250-300℃, and the screw speed is 300-800rpm.

14. The preparation method according to claim 13, characterized in that, The mixing speed in S1 is 300-900 rpm, and the mixing time is 100-400 s. In S4, the extrusion temperature is set in segments from the feed port to the die head: 250-260℃ at the feed port, 280-300℃ for segments one to four, and 250-280℃ for segments five to seven.

15. The use of a PC alloy material, wherein the material is the PC alloy material according to any one of claims 1-11, or the PC alloy material prepared by the preparation method according to any one of claims 12-14, and the material is used in electronic and electrical appliances, home appliances, and digital products.

16. A method for preparing a PC article, wherein the article is made of the PC alloy material according to any one of claims 1-11, or the PC alloy material prepared by the preparation method according to any one of claims 12-14, characterized in that, The method is as follows: after obtaining the product by injection molding, microwave curing is performed.

17. The method according to claim 16, characterized in that, The injection molding machine barrel temperature is set to 300-320℃, injection pressure to 60-80MPaG, mold temperature to 110-130℃, and holding time to 1-3s. The microwave curing power is 100-500W, the irradiation temperature is 80-100℃, and the irradiation time is 1-3min.

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