High hardness pc alloy and method for producing the same

Abstract

The application provides a high-hardness PC alloy and a preparation method thereof. The preparation method comprises the following steps: feeding PC resin and water-containing water-absorbing resin from a main feeding port of an extruder; feeding a silane coupling agent from a side feeding port of the extruder; and extruding and granulating the extruder to obtain a PC alloy material. In the method, the water-absorbing resin degrades the PC to generate PC segments with carboxyl and hydroxyl groups, and then the water-absorbing resin participates in polymerization to form PC-water-absorbing resin segments; the silane coupling agent is added to a rear section of the extruder to react with the terminal -COOH of the PC segment, and a PC resin with silane groups is prepared. The PC resin has strong water absorption capacity after extrusion due to the introduction of water-absorbing groups, and does not need to be dried; the water vapor evaporated in the injection molding process is used to migrate the silane groups to the surface, and crosslinking occurs on the surface to prepare a high-hardness PC, thereby significantly improving the surface hardness and modulus of the PC alloy.

Description

Technical Field

[0001] This invention belongs to the field of polycarbonate, and particularly relates to a high-hardness PC alloy and its preparation method. Background Technology

[0002] Polycarbonate (PC) is a widely used engineering plastic. Due to its high gloss and mechanical strength, PC is used in the appearance components of various products, including 3C products, wall switches, and lighting fixtures. However, PC resin has relatively low surface hardness and modulus, making it prone to scratches and impacts during production, transportation, and use, resulting in surface defects. Therefore, research on high-hardness PC is crucial. Commercially available general-purpose polycarbonate pencil hardness is around 3B, and modulus is around 2200 MPa. Currently, the industry mainly improves surface hardness through painting and modulus by introducing fillers; the former is complex, polluting, and costly, while the latter affects the original high gloss and toughness of PC.

[0003] CN201610227475.3 discloses a painted article coated with a paint composition for glazing polycarbonate, which provides a hard coating on the primer layer by spraying, thereby providing good wear resistance to polycarbonate; CN115785642A discloses a low-temperature resistant high-modulus electromagnetic shielding material and its preparation method, which provides conductivity and high modulus properties by adding 10-20% carbon-based conductive filler.

[0004] Currently, it is not possible to simultaneously and efficiently improve the surface hardness and modulus of PC resin through modification technology without affecting the original properties of the resin. 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 method for preparing a high-hardness PC alloy, which significantly improves the surface hardness and modulus of the PC alloy without affecting the original properties of the resin.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] A method for preparing high-hardness PC alloy materials, the method comprising the following steps:

[0008] S1: PC resin and water-containing water-absorbing resin are fed into the main feed port of the extruder;

[0009] S2: Add the silane coupling agent from the extruder side feed port;

[0010] S3: Extrusion granulation using an extruder to obtain PC alloy material.

[0011] This invention first adds a water-absorbing resin to the front section of the extruder to degrade PC, producing PC segments with carboxyl and hydroxyl groups. The water-absorbing resin then participates in polymerization, forming PC-water-absorbing resin segments. Next, a silane coupling agent is added to the rear section of the extruder to react with the -COOH groups at the ends of the PC segments, preparing a PC resin with silane groups. This PC resin, due to the introduction of water-absorbing groups, exhibits strong water absorption capacity after extrusion, with a moisture content of approximately several thousand ppm. No drying is required; instead, the silane groups migrate to the surface using the water vapor evaporated at high temperatures during injection molding, and cross-linking occurs on the surface, thus preparing high-hardness PC and significantly improving the surface hardness and modulus of the PC alloy.

[0012] For example, the preparation process involves the following reaction:

[0013]

[0014]

[0015] In one embodiment of the present invention, the PC resin in S1 is an aromatic polycarbonate, an aliphatic polycarbonate, and / or an aliphatic polycarbonate, preferably a bisphenol A type polycarbonate, more preferably one or more of Wanhua Chemical 2070, 2100, 2150, 2220, and 2350; preferably, the PC resin has a melt flow index (MFR) of 5-50 g / 10 min under test conditions of 300°C and a load of 1.2 kg, preferably 10-30 g / 10 min; preferably, the PC resin has a mass fraction of 86-98 parts, more preferably 90-95 parts.

[0016] In one embodiment of the present invention, the water-absorbing resin in S1 is an acid-based water-absorbing resin and / or an alcohol-based water-absorbing resin, preferably one or more of acrylic water-absorbing resin, methacrylic resin, and polyethylene glycol resin; preferably, the molecular weight of the water-absorbing resin is 3000-10000.

[0017] In one embodiment of the present invention, the water content of the absorbent resin in S1 is 1-20 wt%, preferably 10-15 wt%; preferably, the water content of the absorbent resin is 2-10 parts by weight, preferably 5-10 parts.

[0018] As is known in the art, antioxidants and other additives may be added to S1. Preferably, the antioxidant is one or more of hindered phenols, benzofurans, acryloyl-modified phenols, and hydroxylamines; more preferably, one or more of hindered phenols.

[0019] In one embodiment of the present invention, the siloxane coupling agent in S2 is a silane coupling agent with a -NH2 group, preferably one or more of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, and γ-aminoethylaminopropyltrimethoxysilane; preferably, the silane coupling agent has a mass fraction of 0.5-2 parts, more preferably 1-1.5 parts.

[0020] In one embodiment of the present invention, the extrusion granulation temperature of the extruder in S3 is 250-300°C, and the screw speed is 300-800 rpm.

[0021] For example, the temperature can be preferably set in segments from the discharge port to the head as follows: 250-260°C at the discharge port, 280-300°C for each of the first to fourth segments, and 250-280°C for each of the fifth to seventh segments.

[0022] Another objective of this invention is to provide a high-hardness PC alloy material.

[0023] A high-hardness PC alloy material, the material being prepared by the method described above, wherein the material is prepared from the following components in parts by weight:

[0024]

[0025] Another object of the present invention is to provide an application of a high-hardness PC alloy material.

[0026] The use of a high-hardness PC alloy material, wherein the material is prepared by the above method or is the above material, and the material is used to prepare high-hardness PC products with a surface pencil hardness of 2H-3H.

[0027] For example, when preparing high-hardness PC products, the injection molding machine barrel temperature is set to 300-320℃, the injection pressure to 60-80 Bar, the mold temperature to 120-130℃, and the holding time to 1-3 seconds.

[0028] Compared with the prior art, the solution of the present invention has the following technical advantages:

[0029] The surface hardness and modulus of the PC alloy were significantly improved (the surface hardness was increased from 2B to 2H-3H, and the modulus was increased from 2100MPa to 2400MPa), achieving high hardness in PC products without affecting the original mechanical and thermal properties of the PC resin. Detailed Implementation

[0030] 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.

[0031] The main sources of raw materials in the examples and comparative examples are shown in Table 1 below:

[0032] Table 1 Raw Material Source Information

[0033]

[0034]

[0035] Unless otherwise specified, all other raw materials and reagents were obtained through commercially available channels.

[0036] 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.

[0037] The performance test parameters and corresponding test methods for PC alloy are as follows:

[0038] Moisture content (%): The moisture content of plastic granules was determined using a moisture meter in accordance with GB / T 2918-1998 "Method for Determination of Moisture Content of Plastic Granules".

[0039] Pencil hardness: GB 6739—86 "Coating Hardness - Pencil Hardness Method" was adopted;

[0040] Flexural strength and modulus (MPa): ISO 178:2010 "Plastics - Determination of flexural properties", speed 2 mm / min;

[0041] Impact strength (MPa): Tested according to ISO 180-2000 "Plastics - Determination of Izod impact strength";

[0042] Heat distortion temperature (°C): Tested according to ISO 75 / B "Plastics - Test method for heat distortion temperature", with a heating rate of 120°C / h.

[0043] Example 1

[0044] High-hardness PC alloys were prepared using the following raw material formulation:

[0045]

[0046]

[0047] The preparation method is as follows:

[0048] a. Place the water-absorbing resin in an environment of 23℃ and 95% humidity for 30 minutes to absorb water, resulting in a water content of 10wt%.

[0049] b. Add PC resin, acrylic water-absorbing resin, and antioxidant from the main feeder of the extruder;

[0050] c. Add γ-aminopropyltriethoxysilane from the side feeder;

[0051] d. 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, 290, 265, 265, 265.

[0052] e. Cool the extruded material in the extruder water tank at 50°C and pelletize it to obtain PC alloy;

[0053] f. The alloy in e is processed into a high-hardness PC alloy product by injection molding at a temperature of 300℃, an injection pressure of 80 Bar, a mold temperature of 120℃, and a holding pressure of 2s.

[0054] Example 2

[0055] High-hardness PC alloys were prepared using the following raw material formulation:

[0056]

[0057] The preparation method is as follows:

[0058] a. Place the water-absorbing resin in an environment of 23℃ and 95% humidity for 20 minutes to absorb water, resulting in a water content of 5%;

[0059] b. Add PC resin, polyethylene glycol resin, and antioxidant from the main feeder of the extruder;

[0060] c. Add γ-aminoethylaminopropyltrimethoxysilane from the side feeder;

[0061] d. 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, 280, 250, 250, 250.

[0062] e. Cool the extruded material in the extruder water tank at 80°C and pelletize it to obtain a high-hardness PC alloy;

[0063] f. The alloy in e is processed into a high-hardness PC alloy product by injection molding at a temperature of 300℃, an injection pressure of 80 Bar, a mold temperature of 120℃, and a holding pressure of 2s.

[0064] Example 3

[0065] High-hardness PC alloys were prepared using the following raw material formulation:

[0066]

[0067] The preparation method is as follows:

[0068] a. Place the water-absorbing resin in an environment of 23℃ and 95% humidity for 50 minutes to absorb water, resulting in a water content of 15%;

[0069] b. Add PC resin, methacrylic resin, and antioxidant from the main feeder of the extruder;

[0070] c. Add γ-aminoethylaminopropyltrimethoxysilane from the side feeder;

[0071] d. 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, 300, 280, 280, 280.

[0072] e. Cool the extruded material in the extruder water tank at 30°C and pelletize it to obtain a high-hardness PC alloy;

[0073] F. The alloy in e is processed into a high-hardness PC alloy product by injection molding at a temperature of 300℃, an injection pressure of 80 Bar, a mold temperature of 120℃, and a holding pressure of 2s.

[0074] Comparative Example 1

[0075] Compared with Example 1, the difference is that γ-aminopropyltriethoxysilane is not added.

[0076] Comparative Example 2

[0077] Compared with Example 1, the difference is that no water-absorbing resin is added.

[0078] Comparative Example 3

[0079] Compared with Example 1, the difference is that the water-absorbing resin does not contain water.

[0080] Comparative Example 4

[0081] Compared with Example 1, the difference is that all raw materials are added to the main feed inlet.

[0082] The PC alloy materials obtained in Examples 1-3 (S1-S3) and Comparative Examples 1-4 (D1-D4) were evaluated by injection molding in an injection molding machine. The screw temperature was set to 260℃ and the screw speed to 250rpm. The performance of the injection-molded samples was tested, and the relevant properties are shown in Table 2.

[0083] Table 2. Performance test results of products in Examples 1-3 (S1-S3) and Comparative Examples 1-4 (D1-D4)

[0084]

[0085]

[0086] As can be seen from Comparative Examples 1-4 and Examples 1-3, the PC alloys in the examples have higher surface hardness and flexural modulus, and the mechanical and thermal properties of the PC alloys are well maintained. In contrast, the comparative examples have disadvantages such as low surface hardness, low toughness, and reduced strength.

[0087] 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 method for preparing high-hardness PC alloy materials, characterized in that, The method includes the following steps: S1: PC resin and water-containing water-absorbing resin are fed into the main feed port of the extruder; S2: Add the silane coupling agent from the extruder side feed port; S3: Extrusion granulation using an extruder to obtain PC alloy material; The water-absorbing resin in S1 is an acid-based water-absorbing resin and / or an alcohol-based water-absorbing resin, with a water content of 1-20 wt%. Wherein, the silane coupling agent described in S2 is a silane coupling agent with a -NH2 group; The method employs the following components in parts by weight, wherein the components contain antioxidants: 86-98 parts of PC resin, 2-10 parts of water-absorbing resin, Antioxidant 0.1-1 part, 0.5-2 parts of siloxane coupling agent.

2. The method according to claim 1, characterized in that, The PC resin mentioned in S1 is an aromatic polycarbonate and / or an aliphatic polycarbonate.

3. The method according to claim 2, characterized in that, S1 The PC resin is bisphenol A type polycarbonate; The PC resin, under test conditions of 300℃ and a load of 1.2kg, has a melt flow index (MFR) of 5-50g / 10min.

4. The method according to claim 3, characterized in that, The PC resin mentioned in S1 is one or more of Wanhua Chemical's 2070, 2100, 2150, 2220, and 2350. The PC resin, under test conditions of 300℃ and a load of 1.2kg, has a melt flow index (MFR) of 10-30g / 10min.

5. The method according to claim 1 or 2, characterized in that, The water-absorbing resin mentioned in S1 is one or more of acrylic water-absorbing resin, methacrylic resin, and polyethylene glycol resin; And / or, the water content of the superabsorbent resin of S1 is 10-15 wt%.

6. The method according to claim 5, characterized in that, The water-absorbing resin has a molecular weight of 3000-10000.

7. The method according to claim 1, characterized in that, The silane coupling agent S2 is one or more of γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, and γ-aminoethylaminopropyltrimethoxysilane.

8. The method according to claim 1, characterized in that, The extrusion granulation temperature of the extruder described in S3 is 250-300℃, and the screw speed is 300-800rpm.

9. A high-hardness PC alloy material, said material being prepared by any one of claims 1-8, characterized in that, The material is prepared from the following components in parts by weight: 86-98 parts of PC resin, 2-10 parts of water-absorbing resin, Antioxidant 0.1-1 part, 0.5-2 parts of siloxane coupling agent.

10. The alloy material according to claim 9, characterized in that, The material is prepared from the following components in parts by weight: 90-95 parts of PC resin, 5-10 parts of water-absorbing resin, Antioxidant 0.2-0.5 parts, 1-1.5 parts of siloxane coupling agent.

11. Use of a high-hardness PC alloy material, wherein the material is prepared by the method of any one of claims 1-8, or is the material of claim 9 or 10, characterized in that, The material is used to prepare high-hardness PC products with a surface pencil hardness of 2H-3H.

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