A low-warpage composite PC reinforced material and its preparation method

Abstract

This invention provides a low-warpage composite PC reinforced material and its preparation method, relating to the field of composite material technology. The preparation method includes: mixing polycarbonate, polysiloxane-PC copolymer, aramid pulp-resin blend, and silica-alumina powder to obtain a first mixture; adding additives to the first mixture and mixing again to obtain a second mixture; feeding the second mixture and glass fiber into a twin-screw extruder for melt extrusion, cooling, and pelletizing to obtain the composite PC modified material. The composite PC modified material obtained by this method exhibits high strength and strong dimensional stability, and is less prone to warping when manufactured into products, making it widely applicable in products such as mobile phone lens holders.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, and particularly to a low-warpage composite PC reinforced material and its preparation method. Background Technology

[0002] Polycarbonate, commonly known as bulletproof plastic, is a high-molecular polymer containing carbonate groups in its molecular chain. Based on the structure of the ester groups, it can be classified into aliphatic, aromatic, and aliphatic-aromatic types. Among these, aliphatic and aliphatic-aromatic polycarbonates have lower mechanical properties, limiting their application in engineering plastics. Only aromatic polycarbonates have achieved industrialized production. Due to the unique structure of polycarbonate, it has become the fastest-growing general-purpose engineering plastic among the five major engineering plastics. Polycarbonate is a strong and tough thermoplastic resin, its name derived from its internal -OC(=O)-O- groups. It can be synthesized from bisphenol A and carbonyl chloride (COCl2). The most commonly used method is the melt transesterification method (bisphenol A and diphenyl carbonate are synthesized through transesterification and polycondensation). Because of its excellent comprehensive properties, polycarbonate has wide applications in optics, automotive, aerospace, electronics, and construction.

[0003] With the rapid development of industries such as electronics, automobiles, military and aerospace, optics, and lighting, polycarbonate (PC) materials are used in many fields, such as automotive headlight covers, LED lamp covers, eyeglass lenses, and mobile phone lenses. This places increasingly higher demands on the mechanical properties of these materials. However, unmodified PC materials have poor dimensional stability and heat resistance, and their injection-molded products are prone to internal stress, leading to cracking. Currently, modified polycarbonate (PC) has become a research focus. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a low-warpage composite PC reinforced material and its preparation method.

[0005] The technical problem solved by this invention is achieved by the following technical solution.

[0006] According to a first aspect of the present invention, a method for preparing a low-warpage composite PC reinforced material is provided, comprising the following steps:

[0007] S1, after stirring and mixing polycarbonate, polysiloxane-PC copolymer, aramid pulp-resin blend and silica-alumina powder, a first mixture is obtained;

[0008] S2, add the additive to the first mixture, stir and mix to obtain the second mixture;

[0009] S3, the mixture and glass fiber are fed into a twin-screw extruder, melt-extruded, cooled and pelletized to obtain a composite PC modified material;

[0010] The preparation method of the aramid pulp-resin blend includes: soaking aramid pulp in an ammonia solution for 10-40 min and then drying it to obtain pretreated aramid pulp; mixing o-cresol epoxy resin and propylene glycol methyl ether, heating to 80-110°C, then adding organic acid and triethylamine, reacting for 0.5-1 h to obtain a resin solution; mixing the pretreated aramid pulp, amino-terminated silicone oil and the resin solution, melting and blending at 80-120°C for 0.5-2 h, washing and drying to obtain the aramid pulp-resin blend.

[0011] In one embodiment of the present invention, in step S3, glass fibers are added from a side feed port on one side of a twin-screw extruder, and the glass fibers are pretreated with a silane coupling agent before being fed.

[0012] In one embodiment of the present invention, the polysiloxane-PC copolymer is prepared according to the following steps:

[0013] Aminophenol was dispersed in a solvent, a catalyst was added, the mixture was heated to 50-70°C, inorganic mineral powder was added, and then hydrogen-terminated polydimethylsiloxane was slowly added dropwise. After the addition was complete, modified polysiloxane was obtained.

[0014] The modified polysiloxane was mixed with diphenyl carbonate, bisphenol A, and lithium acetate catalyst, and then melted in a nitrogen atmosphere at a temperature of 170°C to 190°C. After stirring for 15 to 45 minutes, the temperature was raised to 200°C and held for 0.5 to 1 hour, and then raised to 240°C and held for 0.5 to 1 hour to obtain the polysiloxane-PC copolymer.

[0015] In one embodiment of the present invention, the inorganic mineral powder is selected from one or more of talc powder, mica powder and wollastonite powder.

[0016] In one embodiment of the present invention, the polycarbonate comprises 60-80 parts by weight, the polysiloxane-PC copolymer comprises 8-15 parts by weight, the aramid pulp-resin blend comprises 5-10 parts by weight, the silica-alumina powder comprises 1-5 parts by weight, the glass fiber comprises 2-6 parts by weight, and the additives comprise 1-10 parts by weight.

[0017] In one embodiment of the present invention, the additive is selected from one or more of compatibility toughening agents, antioxidants, lubricants, and color masterbatches.

[0018] In one embodiment of the present invention, the compatibility toughening agent is selected from ethylene terpolymer, the lubricant is selected from silicone powder, and the antioxidant is selected from one or more of antioxidant 1010, antioxidant 168, and antioxidant AT-626.

[0019] In one embodiment of the present invention, the color masterbatch is PC black masterbatch.

[0020] In one embodiment of the present invention, the temperatures of each zone of the twin-screw extruder are as follows: Zone 1 is 200~240℃, Zones 2, 3, and 4 are 250~270℃, Zones 5, 6, and 7 are 220~240℃, Zones 8 and 9 are 230~260℃, Zone 10 is 250~270℃, and the rotation speed of the twin-screw extruder is 300~400 rpm.

[0021] According to a second aspect of the present invention, a low-warpage composite PC reinforced material is provided, which is prepared according to the preparation method described in any one of the above claims.

[0022] The beneficial effects of the low-warpage composite PC reinforced material and its preparation method according to the embodiments of the present invention are as follows:

[0023] The low-warpage composite PC reinforcement material of this invention, by adding glass fiber, aluminosilicate powder, polysiloxane-PC copolymer, aramid pulp-resin blend and additives, can effectively improve the dimensional stability of PC material, so that the product has low warpage and good notched impact strength, and can be applied to products with high requirements for dimensional stability, such as mobile phone lens brackets. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0025] The following is a detailed description of the low-warpage composite PC reinforcement material and its preparation method according to embodiments of the present invention.

[0026] This invention provides a method for preparing a low-warpage composite PC reinforced material, comprising the following steps:

[0027] S1, after stirring and mixing polycarbonate, polysiloxane-PC copolymer, aramid pulp-resin blend and silica-alumina powder, a first mixture is obtained;

[0028] S2, add the additive to the first mixture, stir and mix to obtain the second mixture;

[0029] S3, the mixture and glass fiber are fed into a twin-screw extruder, melt-extruded, cooled and pelletized to obtain a composite PC modified material.

[0030] Specifically, in step S1, the polycarbonate can be a commercially available product, such as Wanhua A1225 polycarbonate.

[0031] Further, in a preferred embodiment of the present invention, in step S1, the polysiloxane-PC copolymer is prepared according to the following steps: aminophenol is dispersed in a solvent, a catalyst is added, the mixture is heated to 50-70°C, inorganic mineral powder is added, and then hydrogen-terminated polydimethylsiloxane is slowly added dropwise. After the addition is complete, a modified polysiloxane is obtained. The modified polysiloxane is mixed with diphenyl carbonate, bisphenol A, and lithium acetate catalyst, and then melted in a nitrogen atmosphere at a temperature of 170-190°C. After stirring for 15-45 min, the temperature is raised to 200°C and held for 0.5-1 h, and then raised to 240°C and held for 0.5-1 h to obtain the polysiloxane-PC copolymer. Specifically, the molar ratio of aminophenol to hydrogen-terminated polydimethylsiloxane (molecular weight 4000) is 2-3:1.

[0032] Introducing aminophenol into hydrogen-terminated polydimethylsiloxane and then in-situ compounding it with inorganic mineral powder effectively improves the affinity with polycarbonate substrates, facilitates the dispersion of inorganic mineral powders, avoids agglomeration, and enhances the mechanical properties and stability of the composite material. Further copolymerization of the modified polysiloxane with PC introduces organosilicon groups into the large, rigid groups in polycarbonate, increasing the length of the structural units, reducing the rigidity of the benzene rings, effectively improving the flexibility of the molecular chains, reducing dimensional changes caused by relative displacement between molecular chains, and improving dimensional stability. Furthermore, compared to directly adding polysiloxane, compounding polysiloxane-PC copolymers with polycarbonate exhibits better compatibility with the substrate, further reducing crystal defects and internal stress.

[0033] Furthermore, in the preparation process of the polysiloxane-PC copolymer, the inorganic mineral powder is selected from one or more of talc powder, mica powder, and wollastonite powder. By adding inorganic mineral powder, the affinity with polycarbonate can be greatly improved, which is beneficial to the bonding with polycarbonate, effectively reducing the coefficient of thermal expansion of the product, ensuring the dimensional stability of the product, and reducing the occurrence of warping.

[0034] Further, in a preferred embodiment of the present invention, step S1, the preparation method of the aramid pulp-resin blend includes: soaking the aramid pulp in an ammonia solution for 10-40 min and then drying it to obtain pretreated aramid pulp; mixing o-cresol epoxy resin and propylene glycol methyl ether, heating to 80-110°C, then adding organic acid and triethylamine, reacting for 0.5-1 h to obtain a resin solution; mixing the pretreated aramid pulp, terminal amino silicone oil and the resin solution, melting and blending at 80-120°C for 0.5-2 h, washing and drying to obtain the aramid pulp-resin blend.

[0035] By first introducing surface-active groups into aramid pulp, and then compounding it with epoxy resin of high epoxy equivalent and amino-terminated silicone oil, the amino-terminated silicone oil promotes good interfacial bonding between the blend and polycarbonate, forming a cross-linked network structure in the matrix and introducing flexible segments to improve the material's toughness and impact resistance. The aramid pulp has high strength and modulus, and forms physical cross-linking points in the matrix, enabling efficient and uniform transmission and dispersion of external stress.

[0036] Further, in a preferred embodiment of the present invention, by weight, the polycarbonate comprises 60-80 parts, the polysiloxane-PC copolymer comprises 8-15 parts, the aramid pulp-resin blend comprises 5-10 parts, the silica-alumina powder comprises 1-5 parts, the glass fiber comprises 2-6 parts, and the additives comprise 1-10 parts. More preferably, in one embodiment, by weight, the polycarbonate comprises 68.8 parts, the polysiloxane-PC copolymer comprises 12.5 parts, the aramid pulp-resin blend comprises 8 parts, the silica-alumina powder comprises 2.5 parts, the glass fiber comprises 3 parts, and the additives comprise 5.2 parts. At this dosage ratio, the raw materials can be fully mixed, synergistically improving the strength and dimensional stability of the product, resulting in a low-warpage product.

[0037] Furthermore, in a preferred embodiment of the present invention, in steps S1 and S2, the stirring and mixing time is 2 to 10 hours, and the stirring speed is 400 r / min to 1200 r / min, for example, the stirring speed is 600 r / min, 800 r / min, etc.

[0038] Furthermore, in a preferred embodiment of the present invention, in step S2, the additive is selected from one or more of a compatibility toughening agent, an antioxidant, a lubricant, and a color masterbatch.

[0039] More preferably, the compatibility toughening agent is selected from ethylene terpolymers, such as DuPont PTW ethylene terpolymer or Arkema AX8900 ethylene terpolymer. By adding a compatibility toughening agent, the raw materials can be effectively compounded, thereby improving the notched impact strength of the product.

[0040] More preferably, the lubricant is selected from silicone powder, and the antioxidant is selected from one or more of antioxidant 1010, antioxidant 168, and antioxidant AT-626. By adding lubricant and antioxidant, the dispersion effect of each raw material can be effectively improved, the injection molding effect can be enhanced, and the surface appearance of the product can be improved.

[0041] More preferably, the color masterbatch is PC black masterbatch. By selecting PC black masterbatch, it has better compatibility with the main substrate, can better disperse and color, and further improve the surface appearance of the product.

[0042] Further, in a preferred embodiment of the present invention, in step S3, glass fibers are added from a side feed port on one side of the twin-screw extruder. The glass fibers are pre-treated with a silane coupling agent before feeding. Examples of silane coupling agents include KH-550, KH-560, and KBE-1003. Before feeding, the glass fibers are sprayed with a silane coupling agent at 2% of the glass fiber's weight and then dried. Pre-treatment with a silane coupling agent further enhances the reinforcing effect of the glass fibers on the substrate, effectively improving the mechanical properties of the product.

[0043] Furthermore, in a preferred embodiment of the present invention, in step S3, the temperatures of each zone of the twin-screw extruder are as follows: Zone 1: 200~240℃; Zones 2, 3, and 4: 250~270℃; Zones 5, 6, and 7: 220~240℃; Zones 8 and 9: 230~260℃; Zone 10: 250~270℃; and the rotational speed of the twin-screw extruder is 300~400 rpm. By controlling the temperatures of each zone of the twin-screw extruder, the melt extrusion process can be effectively regulated, improving the mixing effect of the raw materials and further improving product quality.

[0044] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0045] Example 1

[0046] This embodiment provides a low-warpage composite PC reinforcement material, which is obtained according to the following steps:

[0047] (1) According to the weight parts, prepare the following: 68.8 parts of polycarbonate, 12.5 parts of polysiloxane-PC copolymer, 8 parts of aramid pulp-resin blend, 2.5 parts of silica-alumina powder, 3 parts of glass fiber, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant AT-626, 3 parts of DuPont PTW ethylene terpolymer, 0.3 parts of silicone powder, and 1.5 parts of PC black masterbatch.

[0048] The polysiloxane-PC copolymer was prepared according to the following steps: a. 1.75g ​​of p-aminophenol was dispersed in toluene, a platinum catalyst was added, the mixture was heated to 60℃, 0.8g of mica powder was added, and then 32g of hydrogen-terminated polydimethylsiloxane (molecular weight 4000) was slowly added dropwise. The addition was completed within 2 hours to obtain the modified product; b. Diphenyl carbonate and bisphenol A were mixed in a molar ratio of 1.1:1, and 0.05wt% of lithium acetate catalyst was added. Then 18wt% of the modified product was added and mixed to obtain a mixture; c. The mixture was melted in a nitrogen atmosphere at 180℃, stirred for 30 min, heated to 200℃ and held for 0.5~1 h, and then heated to 240℃ and held for 0.5~1 h to obtain the polysiloxane-PC copolymer.

[0049] The aramid pulp-resin blend was prepared according to the following steps: a. The aramid pulp was impregnated in an ammonia solution for 30 min and then dried to obtain pretreated aramid pulp; b. 200 g of o-cresyl epoxy resin and 45 g of propylene glycol methyl ether were mixed and heated to 105 °C, then 113 g of benzoic acid and 1.2 g of triethylamine were added and reacted for 1 h to obtain a resin solution; c. 20 g of pretreated aramid pulp, 4 g of amino-terminated silicone oil and 76 g of resin solution were mixed and melt-blended at 110 °C for 1.5 h, washed and dried to obtain the aramid pulp-resin blend.

[0050] (2) After stirring polycarbonate, polysiloxane-PC copolymer, aramid pulp-resin blend and silica-alumina powder at 600 r / min for 2 h, mixture A is obtained.

[0051] (3) Add antioxidant 1010, antioxidant AT-62, DuPont PTW ethylene terpolymer, silicone powder and PC black masterbatch to mixture A, and stir for 4 hours at 700 r / min to obtain mixture B.

[0052] (4) Spray the glass fiber with 2% silane coupling agent and then dry it to obtain modified glass fiber.

[0053] (5) Mixture B and modified glass fiber are fed into a twin-screw extruder (the modified glass fiber is added from the side feed port of the twin-screw extruder), melt-extruded at 350 rpm, cooled and pelletized to obtain low-warpage composite PC reinforced material. The twin-screw extruder has the following temperatures: Zone 1: 200~240℃; Zones 2, 3, and 4: 250~270℃; Zones 5, 6, and 7: 220~240℃; Zones 8 and 9: 230~260℃; Zone 10: 250~270℃.

[0054] Example 2

[0055] The low-warpage composite PC reinforcement material provided in this embodiment differs from that in Example 1 in that: the polycarbonate content is 60 parts, the polysiloxane-PC copolymer content is 15 parts, the aramid pulp-resin blend content is 5 parts, the silica-alumina powder content is 5 parts, the glass fiber content is 6 parts, the antioxidant 1010 content is 0.2 parts, the antioxidant AT-626 content is 0.2 parts, the DuPont PTW ethylene terpolymer content is 3 parts, the silicone powder content is 0.5 parts, and the PC black masterbatch content is 1.5 parts.

[0056] Example 3

[0057] The low-warpage composite PC reinforcement material provided in this embodiment differs from that in Example 1 in that: the polycarbonate content is 80 parts, the polysiloxane-PC copolymer content is 8 parts, the aramid pulp-resin blend content is 10 parts, the silica-alumina powder content is 1 part, the glass fiber content is 2 parts, the antioxidant 1010 content is 0.2 parts, the antioxidant AT-626 content is 0.2 parts, the DuPont PTW ethylene terpolymer content is 3 parts, the silicone powder content is 0.5 parts, and the PC black masterbatch content is 1.5 parts.

[0058] Comparative Example 1

[0059] The low-warpage composite PC reinforcement material provided in this comparative example differs from that in Example 1 in that:

[0060] (1) According to the weight parts, prepare the following: 76.8 parts of polycarbonate, 12.5 parts of polysiloxane-PC copolymer, 2.5 parts of silica-alumina powder, 3 parts of glass fiber, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant AT-626, 3 parts of DuPont PTW ethylene terpolymer, 0.3 parts of silicone powder, and 1.5 parts of PC black masterbatch.

[0061] (2) After stirring polycarbonate, polysiloxane-PC copolymer and silica-alumina powder at 600 r / min for 2 h, mixture A is obtained.

[0062] The remaining steps are the same as in Example 1.

[0063] Comparative Example 2

[0064] The low-warpage composite PC reinforcement material provided in this comparative example differs from that in Example 1 in that:

[0065] (1) According to the weight parts, prepare the following: 79.05 parts of polycarbonate, 8 parts of aramid pulp-resin blend, 2.25 parts of hydrogen-terminated polydimethylsiloxane (molecular weight 4000), 2.5 parts of silica-alumina powder, 3 parts of glass fiber, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant AT-626, 3 parts of DuPont PTW ethylene terpolymer, 0.3 parts of silicone powder, and 1.5 parts of PC black masterbatch.

[0066] (2) After stirring polycarbonate, hydrogen-terminated polydimethylsiloxane, aramid pulp-resin blend and silica-alumina powder at 600 r / min for 2 h, mixture A is obtained.

[0067] The remaining steps are the same as in Example 1.

[0068] Comparative Example 3

[0069] The low-warpage composite PC reinforcement material provided in this comparative example differs from that in Example 1 in that:

[0070] (1) According to the weight parts, prepare the following: 89.3 parts of polycarbonate, 2.5 parts of silica-alumina powder, 3 parts of glass fiber, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant AT-626, 3 parts of DuPont PTW ethylene terpolymer, 0.3 parts of silicone powder, and 1.5 parts of PC black masterbatch.

[0071] (2) After stirring polycarbonate and silicon aluminum powder at 600 r / min for 2 h, mixture A is obtained.

[0072] Test case

[0073] The performance of the composite PC reinforced materials obtained in Examples 1-3 and Comparative Examples 1-3 was measured according to the test standards shown in Table 1 below, and the test results are shown in Table 2.

[0074] Table 1

[0075]

[0076] Table 2

[0077]

[0078] In summary, the low-warpage composite PC reinforcement material of the present invention can effectively improve the dimensional stability of PC materials, resulting in products with low warpage and good notched impact strength.

[0079] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method of preparing a low warpage composite PC reinforced material, characterized in that, The method comprises the following steps: S1, stirring and mixing polycarbonate, polysiloxane-PC copolymer, arnos pulp-resin blend and silicon aluminum powder to obtain a first mixture; S2, adding an auxiliary agent to the first mixture and stirring and mixing to obtain a second mixture; the auxiliary agent is selected from one or more of a compatible toughening agent, an antioxidant, a lubricant and a color masterbatch; S3, putting the mixture and glass fiber into a double screw extruder, melt extruding, cooling and granulating to obtain a composite PC modified material; The preparation method of the arnos pulp-resin blend comprises: dipping arnos pulp in an ammonia solution for 10-40 min, and drying to obtain pretreated arnos pulp; mixing o-cresol formaldehyde epoxy resin and propylene glycol methyl ether, heating to 80-110℃, then adding organic acid and triethylamine, and reacting for 0.5-1 h to obtain a resin solution; mixing the pretreated arnos pulp, amino-terminated silicone oil and the resin solution, melt blending at 80-120℃ for 0.5-2 h, washing and drying to obtain the arnos pulp-resin blend; The polysiloxane-PC copolymer is prepared according to the following steps: Disperse amino phenol in a solvent, add a catalyst, heat to 50-70℃, add inorganic mineral powder, then slowly drop amino-terminated polydimethylsiloxane, and obtain modified polysiloxane after the addition is completed; Mix the modified polysiloxane with diphenyl carbonate, bisphenol A and lithium acetate catalyst, melt in a nitrogen atmosphere at a temperature of 170-190℃, stir and react for 15-45 min, then heat to 200℃ and keep for 0.5-1 h, then heat to 240℃ and keep for 0.5-1 h to obtain the polysiloxane-PC copolymer.

2. The method for preparing the low-warpage composite PC reinforced material according to claim 1, characterized in that, In step S3, the glass fiber is added from a side feeding port on one side of the double screw extruder, and the glass fiber is pretreated with a silane coupling agent before feeding.

3. The method for preparing the low-warpage composite PC reinforced material according to claim 1, characterized in that, The inorganic mineral powder is selected from one or more of talc powder, mica powder and wollastonite powder.

4. The method for preparing the low-warpage composite PC reinforced material according to claim 1, characterized in that, The polycarbonate is 60-80 parts, the polysiloxane-PC copolymer is 8-15 parts, the arnos pulp-resin blend is 5-10 parts, the silicon aluminum powder is 1-5 parts, the glass fiber is 2-6 parts, and the auxiliary agent is 1-10 parts by weight.

5. The method for preparing the low-warpage composite PC reinforced material according to claim 1, characterized in that, The compatible toughening agent is selected from ethylene terpolymer, the lubricant is selected from silicone powder, and the antioxidant is selected from one or more of antioxidant 1010, antioxidant 168 and antioxidant AT-626.

6. The method for preparing the low-warpage composite PC reinforced material according to claim 5, characterized in that, The color masterbatch is a PC black masterbatch.

7. The method for preparing the low-warpage composite PC reinforced material according to claim 1, characterized in that, The double screw extruder comprises ten temperature control zones, and the temperature of each zone is as follows: zone one is 200-240℃, zones two, three and four are 250-270℃, zones five, six and seven are 220-240℃, zones eight and nine are 230-260℃, and zone ten is 250-270℃; the rotation speed of the double screw extruder is 300-400 rpm.

8. A low warpage composite PC reinforced material characterized by, The method is prepared according to any one of claims 1-7.

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