PC / PMMA composite board and preparation method thereof

Abstract

The invention discloses a PC / PMMA composite board and a preparation method thereof, and relates to the field of composite materials. Wherein the PC / PMMA composite board comprises a PMMA layer and a PC layer which are arranged up and down, the thickness of the PMMA layer is 45-55 [mu] m, the thickness of the PC layer is 550-650 [mu] m, the PMMA layer is prepared from modified PMMA resin, and the PC layer is prepared from PC resin; the modified PMMA resin is obtained by copolymerizing a methyl methacrylate monomer, N-substituent maleimide, maleic anhydride and a cross-linking agent according to a weight ratio of (65 to 75): (15 to 20): (10 to 15): (5.5 to 6.5). The PC / PMMA composite board provided by the invention has relatively good heat resistance and bending resistance, and has a better popularization value.

Description

Technical Field

[0001] The present invention relates to the field of composite materials, in particular to a PC / PMMA composite board and its preparation method. method. Background Art

[0002] PC / PMMA composite board is a composite material made of polycarbonate (PC) and polymethyl methacrylate (PMMA) through a co-extrusion process. Among them, PMMA has excellent hardness and light transmittance, and PC has good toughness and heat resistance. The combination of PMMA and PC makes the PC / PMMA composite board have the advantages of both PC and PMMA. It can not only meet the requirements of transparency and impact resistance, but also meet the needs of unshielded wireless charging. Therefore, it is widely used in the manufacture of back panels of consumer electronic products, front covers of touch screens, and front covers of car central control screens.

[0003] However, due to the poor heat resistance of PMMA, the edges of the PMMA layer are prone to warping or whitening when the PC / PMMA composite board is heated. The related technology attempts to use the existing anti-whitening PMMA resin to prepare the PMMA layer, but there is a large interface difference between the PMMA layer and the PC layer, so the bending resistance of the PC / PMMA composite board is usually poor. Summary of the invention

[0004] In order to simultaneously improve the heat resistance and bending resistance of the existing PC / PMMA composite board, the present application provides a PC / PMMA composite board and a preparation method thereof.

[0005] In the first aspect, the present application provides a PC / PMMA composite board adopting the following technical solution: A PC / PMMA composite plate, comprising a PMMA layer and a PC layer arranged up and down, wherein the PMMA layer has a thickness of 45-55 μm, the PC layer has a thickness of 550-650 μm, the PMMA layer is made of modified PMMA resin, and the PC layer is made of PC resin; The modified PMMA resin is obtained by copolymerizing methyl methacrylate monomer, N-substituted maleimide, maleic anhydride and a crosslinking agent in a weight ratio of (65-75): (15-20): (10-15): (5.5-6.5).

[0006] Different from the existing ones, the PMMA layer in the PC / PMMA composite board of the present application is made of a modified PMMA resin obtained by copolymerizing methyl methacrylate monomer, N-substituted maleimide, maleic anhydride and a cross-linking agent in a weight ratio of (65-75): (15-20): (10-15): (5.5-6.5), wherein the N-substituted maleimide and maleic anhydride 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 interface compatibility between the PMMA layer and the PC layer, and improve the bending resistance of the PC / PMMA composite board.

[0007] Preferably, the modified PMMA resin is obtained by copolymerizing methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, 4-amino-3-fluoroallyl benzoate and a 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 prepared from a modified PC resin, and the modified PC resin is prepared from a PC resin and a silane coupling agent-modified nano-silica in a weight ratio of 100: (1-1.5).

[0008] In the present application, the modified PMMA resin used in the PMMA layer is further preferably a copolymer of methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, 4-amino-3-fluoroallyl benzoate and a crosslinking agent, and the PC layer preferably uses a modified PC resin prepared by PC resin and silane coupling agent modified nano-silica in a weight ratio of 100: (1-1.5), wherein the optimized modified PMMA resin and modified PC resin can further improve the heat resistance and bending resistance of the PC / PMMA composite board, and the optimized modified PMMA resin and modified PC resin have stable extrusion processing performance, which is conducive to achieving the thickness consistency of the PC / PMMA composite board. It should be noted that in the modified PC resin, the amount of silane coupling agent modified nano-silica should not be too much, otherwise the thickness consistency of the PC / PMMA composite board will decrease.

[0009] In some specific embodiments, the N-substituted maleimide is at least one of N-methylmaleimide and N-cyclohexylmaleimide.

[0010] Preferably, the N-substituted maleimide is a combination of N-methylmaleimide and N-cyclohexylmaleimide, and the weight ratio of the N-methylmaleimide to the N-cyclohexylmaleimide is 1:(1-1.5).

[0011] In this embodiment, the N-substituted maleimide is preferably a composition in which the weight ratio of N-methylmaleimide to N-cyclohexylmaleimide is 1:(1-1.5), which is beneficial to further improve the heat resistance of the PC / PMMA composite board.

[0012] In some specific embodiments, the cross-linking agent is at least one of ethylene glycol dimethacrylate, allyl methacrylate, and triallyl isocyanurate.

[0013] Preferably, the crosslinking agent is a composition of ethylene glycol dimethacrylate and triallyl isocyanurate, and the weight ratio of ethylene glycol dimethacrylate to triallyl isocyanurate is (3-4):1.

[0014] In this embodiment, the crosslinking agent is a composition 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.

[0015] In some specific embodiments, the PC resin has a melt index of 6-10 cm 3 / 10min(300℃ / 1.2kg).

[0016] In this application, PC resin uses a melt index of 6-10cm 3 / 10min (300℃ / 1.2kg) PC resin is conducive to achieving thickness consistency of PC / PMMA composite panels.

[0017] In some specific embodiments, 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.

[0018] In the present application, the nano-silica modified by isocyanate silane coupling agent and the nano-silica modified by epoxy silane coupling agent contain reactive groups that can react with the amino group in 4-amino-3-fluoroallyl benzoate, which is beneficial to improving the interlayer bonding stability of the PC / PMMA composite board and has a promoting effect on improving the bending resistance of the PC / PMMA composite board.

[0019] In the second aspect, the present application provides a method for preparing a PC / PMMA composite plate using the following technical solution: A method for preparing a PC / PMMA composite plate comprises the following steps: S1, adding methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, and a crosslinking agent into toluene, then heating to 75-85°C, adding an azo initiator, reacting at a constant temperature for 3.5-4.5 hours, vacuuming to remove the toluene, and then vacuum drying to obtain a modified PMMA resin; S2, melting the modified PMMA resin at 245-255° C. to obtain a modified PMMA melt, melting the PC resin at 260-270° C. to obtain a PC melt, then distributing the modified PMMA melt and the PC melt into a die head for double-layer composite co-extrusion, followed by plasticization, calendering, and traction cooling to obtain a PC / PMMA composite plate.

[0020] Preferably, in step S1, before heating, 4-amino-3-fluoroallyl benzoate is added to toluene; in step S2, the PC resin is the modified PC resin.

[0021] In summary, this application at least includes the following beneficial technical effects: (1) The PMMA layer in the PC / PMMA composite board of the present application is prepared from a modified PMMA resin obtained by copolymerizing methyl methacrylate monomer, N-substituted maleimide, maleic anhydride and a cross-linking agent in a weight ratio of (65-75): (15-20): (10-15): (5.5-6.5), wherein the N-substituted maleimide and maleic anhydride 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 interface compatibility between the PMMA layer and the PC layer, thereby improving the bending resistance of the PC / PMMA composite board.

[0022] (2) In the present application, the modified PMMA resin used in the PMMA layer is further preferably a copolymer of methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, 4-amino-3-fluoroallyl benzoate and a crosslinking agent, and the PC layer is preferably a modified PC resin prepared by PC resin and silane coupling agent modified nano-silica in a weight ratio of 100: (1-1.5), wherein the optimized modified PMMA resin and modified PC resin can further improve the heat resistance and bending resistance of the PC / PMMA composite board, and the optimized modified PMMA resin and modified PC resin have stable extrusion processing performance, which is conducive to achieving the thickness consistency of the PC / PMMA composite board. It should be noted that in the modified PC resin, the amount of silane coupling agent modified nano-silica should not be too much, otherwise the thickness consistency of the PC / PMMA composite board will decrease. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1It is a structural schematic diagram of a PC / PMMA composite board according to an embodiment of the present application.

[0024] Description of reference numerals: 1. PMMA layer; 2. PC layer. DETAILED DESCRIPTION

[0025] The present application is further described below in conjunction with specific experiments. Example

[0026] [Example 1] A PC / PMMA composite board, referring to Figure 1 , comprising a PMMA layer 1 and a PC layer 2 arranged up and down, wherein the PMMA layer 1 is made of modified PMMA resin, and the raw materials for preparing the modified PMMA resin include 65kg methyl methacrylate monomer, 20kg N-cyclohexylmaleimide, 10kg maleic anhydride, 5.5kg triallyl isocyanurate, 100kg toluene and 0.5kg azobisisobutyronitrile, and the PC layer 2 is made of PC resin, and the PC resin is Teijin Panlite PC L-1250Y, and the melt index of PC L-1250Y is 8cm 3 / 10min.

[0027] The preparation method of the PC / PMMA composite plate of this embodiment comprises the following steps: S1, adding methyl methacrylate monomer, N-cyclohexylmaleimide, maleic anhydride, and triallyl isocyanurate to toluene, then heating to 75°C, adding azobisisobutyronitrile, reacting at constant temperature for 4.5 hours, vacuuming to remove toluene, and then vacuum drying to obtain a modified PMMA resin; S2. The modified PMMA resin is melted at 245°C to obtain a modified PMMA melt, and the PC resin is melted at 260°C to obtain a PC melt. Then, the extrusion speeds of the modified PMMA melt and the PC melt are adjusted according to the thickness of the PMMA layer 1 being 50 μm and the thickness of the PC layer 2 being 600 μm, so that the modified PMMA melt and the PC melt are distributed to the die head for double-layer composite co-extrusion, and then plasticized, calendered, and drawn to cool and shape to obtain a PC / PMMA composite plate.

[0028] [Example 2] A PC / PMMA composite board, referring to Figure 1, comprising a PMMA layer 1 and a PC layer 2 arranged up and down, wherein the PMMA layer 1 is made of modified PMMA resin, and the raw materials for preparing the modified PMMA resin include 75kg methyl methacrylate monomer, 15kg N-methylmaleimide, 15kg maleic anhydride, 6.5kg ethylene glycol dimethacrylate, 100kg toluene and 0.5kg azobisisobutyronitrile, and the PC layer 2 is made of PC resin, and the PC resin is Teijin Panlite PC L-1250Y, and the melt index of PC L-1250Y is 8cm 3 / 10min.

[0029] The preparation method of the PC / PMMA composite plate of this embodiment comprises the following steps: S1, adding methyl methacrylate monomer, N-methylmaleimide, maleic anhydride, and ethylene glycol dimethacrylate into toluene, then heating to 85°C, adding azobisisobutyronitrile, reacting at constant temperature for 3.5 hours, vacuuming to remove toluene, and then vacuum drying to obtain a modified PMMA resin; S2. The modified PMMA resin is melted at 255°C to obtain a modified PMMA melt, and the PC resin is melted at 270°C to obtain a PC melt. Then, the extrusion speeds of the modified PMMA melt and the PC melt are adjusted according to the thickness of the PMMA layer 1 being 50 μm and the thickness of the PC layer 2 being 600 μm, so that the modified PMMA melt and the PC melt are distributed to the die head for double-layer composite co-extrusion, and then plasticized, calendered, and drawn to cool and shape to obtain a PC / PMMA composite plate.

[0030] [Example 3] A PC / PMMA composite board, which is different from [Example 1] in that: 4.5 kg of 4-amino-3-fluoroallyl benzoate was also added to the raw materials for preparing the modified PMMA resin.

[0031] The preparation method of the PC / PMMA composite plate of this embodiment comprises the following steps: S1, adding methyl methacrylate monomer, N-cyclohexylmaleimide, maleic anhydride, triallyl isocyanurate and 4-amino-3-fluoroallyl benzoate to toluene, then heating to 75°C, adding azobisisobutyronitrile, reacting at constant temperature for 4.5 hours, vacuuming to remove toluene, and then vacuum drying to obtain a modified PMMA resin; S2. The modified PMMA resin is melted at 245°C to obtain a modified PMMA melt, and the PC resin is melted at 260°C to obtain a PC melt. Then, the extrusion speeds of the modified PMMA melt and the PC melt are adjusted according to the thickness of the PMMA layer 1 being 50 μm and the thickness of the PC layer 2 being 600 μm, so that the modified PMMA melt and the PC melt are distributed to the die head for double-layer composite co-extrusion, and then plasticized, calendered, and drawn to cool and shape to obtain a PC / PMMA composite plate.

[0032] [Example 4] A PC / PMMA composite board, which differs from [Example 3] in that: 5.5 kg of 4-amino-3-fluoroallyl benzoate was also added to the raw materials for preparing the modified PMMA resin.

[0033] [Example 5] A PC / PMMA composite board, which differs from [Example 3] in that: The PC layer is prepared from modified PC resin, which is obtained by melting PC resin and KH-560 silane coupling agent modified nano-silica at a weight ratio of 100:1 at 260°C, extruding and granulating. The KH-560 silane coupling agent modified nano-silica is obtained by mixing nano-silica and a KH-560 silane coupling agent-ethanol solution with a mass concentration of 1% at a weight ratio of 1:100, stirring for reaction for 1 hour, filtering, and drying the solid.

[0034] The preparation method of the PC / PMMA composite plate of this embodiment comprises the following steps: S1, adding methyl methacrylate monomer, N-cyclohexylmaleimide, maleic anhydride, triallyl isocyanurate and 4-amino-3-fluoroallyl benzoate to toluene, then heating to 75°C, adding azobisisobutyronitrile, reacting at constant temperature for 4.5 hours, vacuuming to remove toluene, and then vacuum drying to obtain a modified PMMA resin; S2. The modified PMMA resin is melted at 245°C to obtain a modified PMMA melt, and the modified PC resin is melted at 260°C to obtain a modified PC melt. Then, the extrusion speeds of the modified PMMA melt and the modified PC melt are adjusted according to the thickness of the PMMA layer 1 being 50 μm and the thickness of the PC layer 2 being 600 μm, so that the modified PMMA melt and the modified PC melt are distributed to the die head for double-layer composite co-extrusion, and then plasticized, calendered, and drawn to cool and shape to obtain a PC / PMMA composite plate.

[0035] Comparative Example [Comparative Example 1] A PC / PMMA composite board, which is different from [Example 1] in that: When preparing the modified PMMA resin, maleic anhydride is replaced by an equimolar amount of N-cyclohexylmaleimide.

[0036] [Comparative Example 2] A PC / PMMA composite board, which is different from [Example 1] in that: When preparing the modified PMMA resin, N-cyclohexylmaleimide is replaced by an equimolar amount of maleic anhydride.

[0037] [Comparative Example 3] A PC / PMMA composite board, which is different from [Example 1] in that: The PMMA layer 1 is made of the anti-whitening AR701 PMMA resin produced by Shanghai Omdari.

[0038] Performance testing (1) Heat resistance test: The PC / PMMA composite plates in the embodiments and comparative examples were placed in ovens at 90°C and 120°C for 30 min, respectively. The plates were taken out and cooled to room temperature. Then, the plates were placed on a flat glass table and the warping height of the edge of the composite plates 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 plates, the better the thermal stability of the PC / PMMA composite plates. At the same time, whether the PC / PMMA composite plate samples would whiten after high temperature treatment was recorded.

[0039] (2) Bending test: The PC / PMMA composite plate was subjected to a bending test using an XHS-ZW-200 bending machine. The plate was bent longitudinally by 170° at a rate of 9° per second. Longitudinal bending refers to the two ends of the composite plate along the calendering direction, with one end fixed and the other end bent. The cracking and breaking of the composite plate were observed. The bending conditions with cracking and breaking as the damage levels increased in turn. The bending angles of the composite plate with the highest damage level were recorded and counted. The bending toughness of the composite plate with cracking was better than that of the composite plate with breaking, and the larger the angle of cracking or breaking, the better the bending toughness.

[0040] (3) Thickness consistency test: 20 points were randomly selected from the PC / PMMA composite plates prepared in each embodiment and comparative example for thickness test, and the thickness deviation of the 20 points was calculated. Thickness deviation = d max -d min , where d max Represents the maximum thickness value, d min Represents the minimum thickness value. The smaller the thickness deviation, the better the thickness consistency of the PC / PMMA composite board.

[0041] Table 1 Table 2 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° cracking 0.4 Comparative Example 3 86° cracking 1.1 Combining Example 1 with Comparative Examples 1-2 and the test data in Table 1-2, it can be seen that adding N-substituted maleimide and maleic anhydride to modify PMMA at the same time can improve the heat resistance of the modified PMMA resin, reduce the edge warping problem and whitening problem of the PC / PMMA composite board, and at the same time, can also improve the interface compatibility between the PMMA layer and the PC layer, and improve the bending resistance of the PC / PMMA composite board.

[0042] Combining Example 1 with Comparative Example 3 and the test data in Tables 1-2, it can be seen that the use of the modified PMMA resin of the present application instead of 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 problem and whitening problem of the PC / PMMA composite board, and at the same time, can also improve the interface compatibility between the PMMA layer and the PC layer, and improve the bending resistance of the PC / PMMA composite board.

[0043] Combined with the test data in Examples 1, 3-5 and Tables 1-2, it can be seen that the modified PMMA resin used in the PMMA layer is further preferably a copolymer of methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, 4-amino-3-fluoroallyl benzoate and a crosslinking agent, and the PC layer preferably uses a modified PC resin prepared by PC resin and silane coupling agent-modified nano-silica in a weight ratio of 100: (1-1.5), which 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 consistency of the PC / PMMA composite board.

[0044] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A PC / PMMA composite board, characterized in that: It comprises a PMMA layer (1) and a PC layer (2) arranged one above the other, wherein the PMMA layer (1) has a thickness of 45-55 μm, and the PC layer (2) has a thickness of 550-650 μm, the PMMA layer (1) is made of modified PMMA resin, and the PC layer (2) is made of PC resin; The modified PMMA resin is obtained by copolymerizing methyl methacrylate monomer, N-substituted maleimide, maleic anhydride and a crosslinking agent in a weight ratio of (65-75): (15-20): (10-15): (5.5-6.5).

2. A PC / PMMA composite board according to claim 1, characterized in that: The modified PMMA resin is obtained by copolymerizing methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, 4-amino-3-fluoroallyl benzoate and a crosslinking agent in a weight ratio of (65-75): (15-20): (10-15): (4.5-5.5): (5.5-6.5). The PC layer is prepared from a modified PC resin, and the modified PC resin is prepared from a PC resin and a silane coupling agent-modified nano-silica in a weight ratio of 100: (1-1.5).

3. A PC / PMMA composite board according to claim 1 or 2, characterized in that: The N-substituted maleimide is at least one of N-methylmaleimide and N-cyclohexylmaleimide.

4. A PC / PMMA composite board according to claim 3, characterized in that: The N-substituted maleimide is a composition of N-methylmaleimide and N-cyclohexylmaleimide, and the weight ratio of the N-methylmaleimide to the N-cyclohexylmaleimide is 1:(1-1.5).

5. A PC / PMMA composite board according to claim 1 or 2, characterized in that: The cross-linking agent is at least one of ethylene glycol dimethacrylate, allyl methacrylate and triallyl isocyanurate.

6. The PC / PMMA composite board according to claim 5, characterized in that: The crosslinking agent is a composition of ethylene glycol dimethacrylate and triallyl isocyanurate, and the weight ratio of the ethylene glycol dimethacrylate to triallyl isocyanurate is (3-4):

1.

7. A PC / PMMA composite board according to claim 1 or 2, characterized in that: The PC resin has a melt index of 6-10 cm 3 / 10min (300℃ / 1.2kg).

8. The PC / PMMA composite board according to claim 2, characterized in that: The silane coupling agent modified nano-silica adopts at least one of isocyanate silane coupling agent modified nano-silica and epoxy silane coupling agent modified nano-silica.

9. A method for preparing a PC / PMMA composite board according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, adding methyl methacrylate monomer, N-substituted maleimide, maleic anhydride, and a crosslinking agent into toluene, then heating to 75-85°C, adding an azo initiator, reacting at a constant temperature for 3.5-4.5 hours, vacuuming to remove the toluene, and then vacuum drying to obtain a modified PMMA resin; S2, melting the modified PMMA resin at 245-255° C. to obtain a modified PMMA melt, melting the PC resin at 260-270° C. to obtain a PC melt, then distributing the modified PMMA melt and the PC melt into a die head for double-layer composite co-extrusion, followed by plasticization, calendering, and traction cooling to obtain a PC / PMMA composite plate.

10. The method for preparing a PC / PMMA composite board according to claim 9, characterized in that: In step S1, 4-amino-3-fluoroallyl benzoate is added to toluene before heating; in step S2, the PC resin is the modified PC resin described in claim 2.

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