PC / PMMA composite board and preparation method thereof

Abstract

The application discloses a PC / PMMA composite board and a preparation method thereof, and relates to the field of composite materials. The PC / PMMA composite board comprises PMMA layers and PC layers arranged in an up-down mode, the thickness of the PMMA layers is 45-55 microns, the thickness of the PC layers is 550-650 microns, the PMMA layers are prepared from modified PMMA resins, and the PC layers are prepared from PC resins; the modified PMMA resins are obtained by copolymerization of methyl methacrylate monomers, N-substituted maleimide, maleic anhydride and a crosslinking agent in a weight ratio of (65-75):(15-20):(10-15):(5.5-6.5). The PC / PMMA composite board has better heat resistance and bending resistance, and has better popularization value.

Description

Technical Field

[0001] This application relates to the field of composite materials, and in particular to a PC / PMMA composite plate and its preparation.

[0002] method. Background Technology

[0003] PC / PMMA composite panels are composite materials made from polycarbonate (PC) and polymethyl methacrylate (PMMA) through a co-extrusion process. PMMA has excellent hardness and light transmittance, while PC has good toughness and heat resistance. The combination of PMMA and PC gives PC / PMMA composite panels the advantages of both PC and PMMA, meeting the requirements for transparency and impact resistance, as well as the need for unshielded wireless charging. Therefore, they are widely used in the manufacture of back panels for consumer electronics products, front covers for touch screens, and front covers for automotive center console screens.

[0004] However, due to the poor heat resistance of PMMA, the edges of the PMMA layer in PC / PMMA composite boards are prone to warping or whitening when heated. In related technologies, attempts have been made to use existing anti-whitening PMMA resin to prepare the PMMA layer. However, there is a large interface difference between the PMMA layer and the PC layer, so the bending resistance of PC / PMMA composite boards is usually poor. Summary of the Invention

[0005] In order to simultaneously improve the heat resistance and bending resistance of existing PC / PMMA composite panels, this application provides a PC / PMMA composite panel and its preparation method.

[0006] Firstly, the PC / PMMA composite board provided in this application adopts the following technical solution:

[0007] A PC / PMMA composite board includes a PMMA layer and a PC layer disposed on top of each other. The thickness of the PMMA layer is 45-55 μm, and the thickness of the PC layer is 550-650 μm. The PMMA layer is made of modified PMMA resin, and the PC layer is made of PC resin.

[0008] The modified PMMA resin is obtained by copolymerization of methyl methacrylate monomer, N-substituted maleimide, maleic anhydride and crosslinking agent in a weight ratio of (65-75):(15-20):(10-15):(5.5-6.5).

[0009] Unlike existing methods, the PMMA layer in the PC / PMMA composite board of this application is made of modified PMMA resin obtained by copolymerization of methyl methacrylate monomer, N-substituted maleimide, maleic anhydride and crosslinking agent in a weight ratio of (65-75):(15-20):(10-15):(5.5-6.5). Among them, N-substituted maleimide and maleic anhydride can improve the heat resistance of modified PMMA resin, reduce edge warping and whitening problems of PC / PMMA composite board, and improve the interfacial compatibility between PMMA layer and PC layer, thereby improving the bending resistance of PC / PMMA composite board.

[0010] Preferably, the modified PMMA resin is obtained by copolymerization of methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, 4-amino-3-fluoroallyl benzoate and crosslinking agent in a weight ratio of (65-75):(15-20):(10-15):(4.5-5.5):(5.5-6.5), and the PC layer is made of modified PC resin, which is obtained by PC resin and silane coupling agent modified nano-silica in a weight ratio of 100:(1-1.5).

[0011] In this application, the modified PMMA resin used in the PMMA layer is preferably a copolymer of methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, 4-amino-3-fluoroallyl benzoate, and a crosslinking agent. The PC layer is preferably a modified PC resin prepared by mixing PC resin and silane coupling agent-modified nano-silica at a weight ratio of 100:(1-1.5). This optimized modified PMMA resin and modified PC resin can further improve the heat resistance and bending resistance of the PC / PMMA composite board. Furthermore, the optimized modified PMMA resin and modified PC resin have stable extrusion processing properties, which is beneficial for achieving uniform thickness in the PC / PMMA composite board. It should be noted that the amount of silane coupling agent-modified nano-silica in the modified PC resin should not be excessive, otherwise it will cause a decrease in the thickness uniformity of the PC / PMMA composite board.

[0012] In some specific embodiments, the N-substituted maleimide is at least one of N-methylmaleimide and N-cyclohexylmaleimide.

[0013] Preferably, the N-substituted maleimide is a composition of N-methylmaleimide and N-cyclohexylmaleimide, wherein the weight ratio of N-methylmaleimide to N-cyclohexylmaleimide is 1:(1-1.5).

[0014] In this embodiment, the N-substituted maleimide is preferably a combination of N-methylmaleimide and N-cyclohexylmaleimide in a weight ratio of 1:(1-1.5), which is beneficial to further improve the heat resistance of the PC / PMMA composite board.

[0015] In some specific embodiments, the crosslinking agent is at least one of ethylene glycol dimethacrylate, allyl methacrylate, and triallyl isocyanurate.

[0016] Preferably, the crosslinking agent is a composition of ethylene glycol dimethacrylate and triallyl isocyanurate, wherein the weight ratio of ethylene glycol dimethacrylate to triallyl isocyanurate is (3-4):1.

[0017] In this embodiment, the crosslinking agent is a combination of ethylene glycol dimethacrylate and triallyl isocyanurate in a weight ratio of (3-4):1, which is beneficial to further improve the heat resistance and bending resistance of the PC / PMMA composite board.

[0018] In some specific embodiments, the melt flow index of the PC resin is 6-10 cm⁻¹. 3 / 10min (300℃ / 1.2kg).

[0019] In this application, the PC resin used has a melt index of 6-10 cm⁻¹ 3 A 10-minute (300℃ / 1.2kg) application of PC resin is beneficial for achieving consistent thickness in PC / PMMA composite boards.

[0020] In some specific embodiments, the silane coupling agent modified nano-silica is at least one of isocyanate-based silane coupling agent modified nano-silica and epoxy-based silane coupling agent modified nano-silica.

[0021] In this application, the nano-silica modified with isocyanate-based silane coupling agent and the nano-silica modified with epoxy-based silane coupling agent contain reactive groups that can react with the amino groups in 4-amino-3-fluoroallyl benzoate, which is beneficial to improving the interlayer bonding stability of PC / PMMA composite board and promotes the improvement of the bending resistance of PC / PMMA composite board.

[0022] Secondly, the method for preparing a PC / PMMA composite board provided in this application adopts the following technical solution:

[0023] A method for preparing a PC / PMMA composite board includes the following steps:

[0024] S1. Methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, and crosslinking agent are added to toluene, and then the temperature is raised to 75-85℃. Azo initiator is added, and the reaction is carried out at a constant temperature for 3.5-4.5 hours. Toluene is removed by vacuum, and then vacuum drying is performed to obtain modified PMMA resin.

[0025] S2. The modified PMMA resin is melted at 245-255℃ to obtain a modified PMMA melt, and the PC resin is melted at 260-270℃ to obtain a PC melt. Then, the modified PMMA melt and the PC melt are distributed to a die head for double-layer composite co-extrusion, followed by plasticizing, calendering, traction cooling and shaping to obtain a PC / PMMA composite board.

[0026] Preferably, in step S1, 4-amino-3-fluoroallyl benzoate is added to toluene before heating; in step S2, the modified PC resin is used.

[0027] In summary, this application includes at least the following beneficial technical effects:

[0028] (1) The PMMA layer in the PC / PMMA composite board of this application is made of modified PMMA resin obtained by copolymerization of methyl methacrylate monomer, N-substituted maleimide, maleic anhydride and crosslinking agent in a weight ratio of (65-75):(15-20):(10-15):(5.5-6.5). Among them, N-substituted maleimide and maleic anhydride can improve the heat resistance of modified PMMA resin, reduce the occurrence of edge warping and whitening problems of PC / PMMA composite board, and at the same time, improve the interfacial compatibility between PMMA layer and PC layer, and improve the bending resistance of PC / PMMA composite board.

[0029] (2) In this application, the modified PMMA resin used in the PMMA layer is preferably a copolymer of methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, 4-amino-3-fluoroallyl benzoate, and a crosslinking agent. The PC layer is preferably a modified PC resin prepared by mixing PC resin and silane coupling agent modified nano-silica at a weight ratio of 100:(1-1.5). The optimized modified PMMA resin and modified PC resin can further improve the heat resistance and bending resistance of the PC / PMMA composite board. Furthermore, the optimized modified PMMA resin and modified PC resin have stable extrusion processing performance, which is beneficial for achieving uniform thickness of the PC / PMMA composite board. It should be noted that the amount of silane coupling agent modified nano-silica in the modified PC resin should not be excessive, otherwise it will cause a decrease in the uniform thickness of the PC / PMMA composite board. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a PC / PMMA composite board according to an embodiment of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. PMMA layer; 2. PC layer. Detailed Implementation

[0033] The following section provides further explanation of this application in conjunction with specific experiments.

[0034] Example

[0035]

Example 1

[0036] A PC / PMMA composite board, as shown in the reference Figure 1 It includes a PMMA layer 1 and a PC layer 2, arranged vertically. PMMA layer 1 is made of modified PMMA resin, the raw materials for which include 65 kg of methyl methacrylate monomer, 20 kg of N-cyclohexylmaleimide, 10 kg of maleic anhydride, 5.5 kg of triallyl isocyanurate, 100 kg of toluene, and 0.5 kg of azobisisobutyronitrile. PC layer 2 is made of PC resin, specifically Teijin Panlite PC L-1250Y, with a melt flow index of 8 cm⁻¹. 3 / 10min.

[0037] The preparation method of the PC / PMMA composite board in this embodiment includes the following steps:

[0038] S1. Methyl methacrylate monomer, N-cyclohexylmaleimide, maleic anhydride, and triallyl isocyanurate were added to toluene, and then the temperature was raised to 75°C. Azobisisobutyronitrile was added, and the reaction was carried out at a constant temperature for 4.5 h. Toluene was removed by vacuum, and then the product was dried under vacuum to obtain modified PMMA resin.

[0039] S2. Modified PMMA resin is melted at 245℃ to obtain modified PMMA melt, and PC resin is melted at 260℃ to obtain PC melt. Then, the extrusion speed of modified PMMA melt and PC melt is adjusted according to the thickness of PMMA layer 1 being 50μm and the thickness of PC layer 2 being 600μm, so that the modified PMMA melt and PC melt are distributed to the die head for double-layer composite co-extrusion. Then, plasticizing, calendering, traction cooling and shaping are performed to obtain PC / PMMA composite board.

[0040]

Example 2

[0041] A PC / PMMA composite board, as shown in the reference Figure 1It includes a PMMA layer 1 and a PC layer 2, arranged vertically. PMMA layer 1 is made of modified PMMA resin, the raw materials for which include 75 kg of methyl methacrylate monomer, 15 kg of N-methylmaleimide, 15 kg of maleic anhydride, 6.5 kg of ethylene glycol dimethacrylate, 100 kg of toluene, and 0.5 kg of azobisisobutyronitrile. PC layer 2 is made of PC resin, specifically Teijin Panlite PC L-1250Y, with a melt flow index of 8 cm⁻¹. 3 / 10min.

[0042] The preparation method of the PC / PMMA composite board in this embodiment includes the following steps:

[0043] S1. Methyl methacrylate monomer, N-methylmaleimide, maleic anhydride, and ethylene glycol dimethacrylate are added to toluene, then the temperature is raised to 85°C, azobisisobutyronitrile is added, and the reaction is kept at a constant temperature for 3.5 hours. After removing the toluene by vacuum, the product is then dried under vacuum to obtain the modified PMMA resin.

[0044] S2. Modified PMMA resin is melted at 255℃ to obtain modified PMMA melt, and PC resin is melted at 270℃ to obtain PC melt. Then, the extrusion speed of modified PMMA melt and PC melt is adjusted according to the thickness of PMMA layer 1 being 50μm and the thickness of PC layer 2 being 600μm, so that the modified PMMA melt and PC melt are distributed to the die head for double-layer composite co-extrusion. Then, plasticizing, calendering, traction cooling and shaping are performed to obtain PC / PMMA composite board.

[0045]

Example 3

[0046] A PC / PMMA composite board differs from [Example 1] in that:

[0047] The raw materials for preparing the modified PMMA resin also included 4.5 kg of 4-amino-3-fluoroallyl benzoate.

[0048] The preparation method of the PC / PMMA composite board in this embodiment includes the following steps:

[0049] S1. Methyl methacrylate monomer, N-cyclohexylmaleimide, maleic anhydride, triallyl isocyanurate and 4-amino-3-fluoroallyl benzoate were added to toluene, then heated to 75°C, azobisisobutyronitrile was added, and the mixture was reacted at a constant temperature for 4.5 h. Toluene was removed by vacuum, and then the mixture was dried under vacuum to obtain modified PMMA resin.

[0050] S2. Modified PMMA resin is melted at 245℃ to obtain modified PMMA melt, and PC resin is melted at 260℃ to obtain PC melt. Then, the extrusion speed of modified PMMA melt and PC melt is adjusted according to the thickness of PMMA layer 1 being 50μm and the thickness of PC layer 2 being 600μm, so that the modified PMMA melt and PC melt are distributed to the die head for double-layer composite co-extrusion. Then, plasticizing, calendering, traction cooling and shaping are performed to obtain PC / PMMA composite board.

[0051]

Example 4

[0052] A PC / PMMA composite board differs from [Example 3] in that:

[0053] 5.5 kg of 4-amino-3-fluoroallyl benzoate was also added to the raw materials for the preparation of modified PMMA resin.

[0054]

Example 5

[0055] A PC / PMMA composite board differs from [Example 3] in that:

[0056] The PC layer is made of modified PC resin. The modified PC resin is obtained by melting PC resin and KH-560 silane coupling agent modified nano-silica at a weight ratio of 100:1 at 260℃, followed by extrusion and granulation. Specifically, the KH-560 silane coupling agent modified nano-silica is obtained by mixing nano-silica with a 1% KH-560 silane coupling agent-ethanol solution at a weight ratio of 1:100, stirring and reacting for 1 hour, then filtering, and drying the solid.

[0057] The preparation method of the PC / PMMA composite board in this embodiment includes the following steps:

[0058] S1. Methyl methacrylate monomer, N-cyclohexylmaleimide, maleic anhydride, triallyl isocyanurate and 4-amino-3-fluoroallyl benzoate were added to toluene, then heated to 75°C, azobisisobutyronitrile was added, and the mixture was reacted at a constant temperature for 4.5 h. Toluene was removed by vacuum, and then the mixture was dried under vacuum to obtain modified PMMA resin.

[0059] S2. Modified PMMA resin is melted at 245℃ to obtain modified PMMA melt, and modified PC resin is melted at 260℃ to obtain modified PC melt. Then, the extrusion speed of modified PMMA melt and modified PC melt is adjusted according to the thickness of PMMA layer 1 being 50μm and the thickness of PC layer 2 being 600μm, so that the modified PMMA melt and modified PC melt are distributed to the die head for double-layer composite co-extrusion. Then, plasticizing, calendering, traction cooling and shaping are performed to obtain PC / PMMA composite board.

[0060] Comparative Example

[0061] Comparative Example 1

[0062] A PC / PMMA composite board differs from [Example 1] in that:

[0063] When preparing modified PMMA resin, maleic anhydride is replaced by an equimolar amount of N-cyclohexylmaleimide.

[0064] Comparative Example 2

[0065] A PC / PMMA composite board differs from [Example 1] in that:

[0066] When preparing modified PMMA resin, N-cyclohexylmaleimide is replaced by an equimolar amount of maleic anhydride.

[0067] Comparative Example 3

[0068] A PC / PMMA composite board differs from [Example 1] in that:

[0069] PMMA layer 1 is made of anti-whitening AR701 PMMA resin from Shanghai Wengda Rui.

[0070] Performance testing

[0071] (1) Heat resistance test: The PC / PMMA composite plates in each example and comparative example were placed in ovens at 90℃ and 120℃ respectively and baked for 30 minutes. After being taken out and cooled to room temperature, they were placed on a flat glass table and the warping height of the composite plate edge was measured with a feeler gauge. For PC / PMMA composite plates with the same heat treatment temperature, the smaller the warping height of the composite plate, the better the thermal stability of the PC / PMMA composite plate. At the same time, it was recorded whether the PC / PMMA composite plate sample would whiten after high temperature treatment.

[0072] (2) Bending test: The PC / PMMA composite board was bent using an XHS-ZW-200 bending machine. The longitudinal bending was 170° and the bending rate was 9° per second. Longitudinal bending refers to bending the composite board along both ends of the rolling direction, with one end fixed and the other end bent. The occurrence of cracking and breakage of the composite board was observed. The occurrence of cracking and breakage was considered as the progressive increase of the damage level. The bending angle when the composite board reached the highest damage level was recorded and statistically analyzed. The bending toughness of the composite board with cracks was better than that with breakage. The larger the angle of cracking or breakage, the better the bending toughness.

[0073] (3) Thickness consistency test: 20 points were randomly selected from the PC / PMMA composite boards prepared in each embodiment and comparative example for thickness testing. The thickness deviation at the 20 points was calculated as follows: Thickness deviation = dmax -d min , where d max Represents the maximum thickness value, d min This represents the minimum thickness value. The smaller the thickness deviation, the better the thickness consistency of the PC / PMMA composite board.

[0074] Table 1

[0075]

[0076]

[0077] Table 2

[0078] Sample Bending test Thickness deviation / μm Example 1 97° cracking 0.4 Example 2 98° cracking 0.8 Example 3 94° cracking 1.2 Example 4 92° cracking 1.5 Example 5 101° cracking 0.6 Comparative Example 1 88° cracking 0.5 Comparative Example 2 90° crack 0.4 Comparative Example 3 86° cracking 1.1

[0079] Based on the test data in Example 1, Comparative Examples 1-2, and Table 1-2, it can be seen that the simultaneous addition of N-substituted maleimide and maleic anhydride to modify PMMA can improve the heat resistance of the modified PMMA resin, reduce the occurrence of edge warping and whitening problems in PC / PMMA composite boards, and also improve the interfacial compatibility between the PMMA layer and the PC layer, thereby improving the bending resistance of the PC / PMMA composite board.

[0080] Based on the test data in Example 1, Comparative Example 3, and Tables 1-2, it can be seen that using the modified PMMA resin of this application to replace the existing anti-whitening AR701 PMMA resin to prepare the PMMA layer can improve the heat resistance of the modified PMMA resin, reduce the edge warping and whitening problems of the PC / PMMA composite board, and at the same time, improve the interfacial compatibility between the PMMA layer and the PC layer, thereby improving the bending resistance of the PC / PMMA composite board.

[0081] Based on the test data in Examples 1, 3-5 and Table 1-2, it can be seen that the modified PMMA resin used in the PMMA layer is preferably a copolymer of methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, 4-amino-3-fluoroallyl benzoate and crosslinking agent. The PC layer is preferably a modified PC resin prepared by PC resin and silane coupling agent modified nano-silica at a weight ratio of 100:(1-1.5). This can further improve the heat resistance and bending resistance of the PC / PMMA composite board, and at the same time, it is beneficial to achieve the thickness uniformity of the PC / PMMA composite board.

[0082] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A PC / PMMA composite board, characterized by: The PC / PMMA composite board comprises a PMMA layer (1) and a PC layer (2) arranged in a top-bottom manner, wherein the thickness of the PMMA layer (1) is 45-55 μm, and the thickness of the PC layer (2) is 550-650 μm; the PMMA layer (1) is made of a modified PMMA resin, and the PC layer (2) is made of a modified PC resin. The modified PMMA resin is obtained by copolymerization of methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, 4-amino-3-fluoroallyl benzoate and crosslinking agent in a weight ratio of (65-75):(15-20):(10-15):(4.5-5.5):(5.5-6.5), and the modified PC resin is obtained by modifying PC resin with silane coupling agent modified nano-silica in a weight ratio of 100:(1-1.5). The silane coupling agent modified nano-silica is at least one of isocyanate silane coupling agent modified nano-silica and epoxy silane coupling agent modified nano-silica. The crosslinking agent is at least one of ethylene glycol dimethacrylate, allyl methacrylate and triallyl isocyanurate.

2. The PC / PMMA composite board according to claim 1, characterized in that: The N-substituted maleimide is at least one of N-methyl maleimide and N-cyclohexyl maleimide.

3. The PC / PMMA composite board according to claim 2, characterized in that: The N-substituted maleimide is a combination of N-methyl maleimide and N-cyclohexyl maleimide, and the weight ratio of N-methyl maleimide to N-cyclohexyl maleimide is 1:(1-1.5).

4. The PC / PMMA composite board according to claim 1, characterized in that: The crosslinking agent is a combination of ethylene glycol dimethacrylate and triallyl isocyanurate, and the weight ratio of ethylene glycol dimethacrylate to triallyl isocyanurate is (3-4):

1.

5. The PC / PMMA composite board according to claim 1, characterized in that: The PC resin has a melt index (300°C, 1.2 kg) of 6-10 cm 3 / 10 min.

6. A method for producing a PC / PMMA composite board according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S1, methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, crosslinking agent and 4-amino-3-fluoroallyl benzoate are added to toluene, then heated to 75-85℃, azo initiator is added, constant temperature reaction for 3.5-4.5h, vacuum removal of toluene, then vacuum drying, to obtain a modified PMMA resin; S2, the modified PMMA resin is melted at 245-255℃ to obtain a modified PMMA melt, and the modified PC resin is melted at 260-270℃ to obtain a modified PC melt, then the modified PMMA melt and the modified PC melt are distributed into a die for double-layer composite co-extrusion, then plasticized, calendered, and cooled and shaped to obtain a PC / PMMA composite board.

Images