Polymer composite material for manufacturing plastic shell of electric appliance

Abstract

The invention relates to the technical field of materials, and discloses a polymer composite material for manufacturing a plastic shell of an electric appliance, the polymer composite material is prepared by taking PET as a base material and taking an elastomer, modified quartz fiber and the like as auxiliary materials through melt extrusion granulation, the modified quartz fiber is prepared by modifying a macromolecular substance on the surface of the quartz fiber, and the modified quartz fiber is prepared by a melt extrusion granulation method. The macromolecular substance contains carboxyl substituent groups in an L-lysine structure, and the carboxyl substituent groups can participate in a chain extension process of PET, so that strong interlacing is generated between the macromolecular substance and a PET molecular chain, and a cross-linked network taking quartz fiber as a cross-linked core point is formed, thereby efficiently utilizing the potential of the quartz fiber, and improving the crosslinking property of the PET. And the surface of the composite material has excellent mechanical properties. Besides, the macromolecular substance structure contains a rigid benzo norbornane heterocyclic structure, and the rigid heterocyclic structure can greatly improve the stability of a PET molecular chain, so that the composite material can show excellent high-temperature resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, in particular to a polymer composite material for making a plastic housing of an electrical appliance. Background Art

[0002] With the advancement of science and technology and the increasing abundance of electronic products, plastic casings for electrical appliances are playing an increasingly important role in protecting internal components, providing an aesthetically pleasing appearance, and enhancing user experience. Plastic casings are widely used in various electrical products due to their multiple advantages, including light weight, low cost, safe insulation, easy molding, corrosion resistance, good heat insulation, easy cleaning, and environmental protection. As a key component for protecting internal components, providing an aesthetically pleasing appearance, and enhancing user experience, the casing of electrical equipment has strict requirements on the selection of materials. Among many polymer materials, polyethylene terephthalate (PET), as an important thermoplastic polyester, has become one of the ideal base materials for making plastic casings for electrical appliances due to its unique electrical insulation properties, good safety performance, and excellent fatigue resistance, and has been widely used in recent years.

[0003] However, PET itself has significant flaws. Pure PET has low heat resistance, with a heat deformation temperature of only around 85°C. However, electrical appliances can generate significant heat during use, requiring the plastic housing to continuously operate in high-temperature environments. This can easily cause the PET housing to lose its original shape and strength, affecting the lifespan and performance of the appliance. Furthermore, PET's mechanical properties lag behind those of traditional thermosetting plastics, making PET products susceptible to damage during transportation and use, thus losing their value. Therefore, effectively enhancing and modifying PET is key to further expanding its application in the field of electrical appliance housings. Summary of the Invention

[0004] In order to solve the problems mentioned in the background art, the object of the present invention is to provide a polymer composite material for making a plastic housing of an electrical appliance.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A polymer composite material for making a plastic housing of an electrical appliance, comprising the following raw materials measured in parts by weight:

[0007]

[0008] As a further embodiment of the present invention, the method for preparing the polymer composite material comprises the following steps:

[0009] The first step is to weigh each raw material according to the weight to complete the material preparation;

[0010] The second step is to heat and dry the PET, chain extender, and modified quartz fiber, and then place them in a torque rheometer, control the temperature to 260-280°C, and the screw speed to 50-60rpm. After 1-3 hours, cool down and discharge the material to form a precursor material;

[0011] The third step is to add the precursor, elastomer, microcrystalline cellulose, antioxidant and lubricant into the mixing kettle, start stirring, set the stirring rate to 300-500r / min, the temperature to 100-120℃, stir and mix evenly, and then feed the mixture into the twin-screw extruder through the feeding port for melt extrusion.

[0012] As a further embodiment of the present invention, the specific preparation method of the modified quartz fiber comprises the following steps:

[0013] Step S1, dispersing quartz fiber in an ethanol medium, and adding a silane coupling agent to the formed dispersion, then stirring at a temperature of 60-70° C. for 4-8 hours, cooling and discharging, thereby obtaining an organic quartz fiber;

[0014] Step S2, adding organic quartz fiber to N,N-dimethylformamide, controlling the ultrasonic frequency to 100-120kHz, ultrasonically treating for 20-40min, then adding L-lysine, after the addition is completed, raising the temperature to 60-70°C, stirring for 4-8h, and then continuing to add the bridging connector and acid binding agent. After the addition is completed, the temperature is further raised to 80-90°C, stirring for 12-24h, stopping heating, cooling the material, and separating and collecting the solid material.

[0015] As a further embodiment of the present invention, in step S1, the silane coupling agent is any one of 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane or 3-bromopropyltrimethoxysilane.

[0016] As a further embodiment of the present invention, in step S2, the specific preparation method of the bridging linker is as follows:

[0017] Add 3,6-dihydroxybenzonorbornane and acetone to a reactor filled with nitrogen, start stirring after the addition, mix evenly, and place in an ice bath environment. Then continue to add the halogenated compound and catalyst to the reactor. After the addition is completed, remove the ice bath, stir at room temperature for 3-6 hours, remove the nitrogen, evaporate the solvent, and purify the collected product to obtain a bridging connector.

[0018] As a further embodiment of the present invention, the molar ratio of the 3,6-dihydroxybenzonorbornane to the halogenated compound is 1:2.

[0019] As a further embodiment of the present invention, the halogenated compound is chloroacetyl chloride, bromoacetyl bromide or 4-bromobutyryl chloride.

[0020] As a further embodiment of the present invention, the catalyst is pyridine or triethylamine.

[0021] As a further solution of the present invention, in step S2, the acid binding agent is a sodium hydroxide solution with a mass fraction of 10-15%.

[0022] In the above technical solution, a silane coupling agent containing a halogen substituent is first used to modify the surface of the quartz fiber, and the halogen substituent is modified on the surface of the quartz fiber to obtain a functionalized organic quartz fiber. Then, L-lysine and a bridging connector are used as polymers, and L-lysine is used as a chain extender to first replace the halogen substituent in the organic quartz fiber structure, and then continuously replace the halogen substituent in the bridging connector structure. Finally, a macromolecular substance with an alternating structure is modified on the surface of the quartz fiber to obtain a modified quartz fiber.

[0023] Among them, the bridging linker is prepared by a condensation reaction of 3,6-dihydroxybenzonorbornane and a halogenated compound under the action of a catalyst. By controlling the dosage ratio of the two, a benzonorbornane derivative with an oil-equivalent halogen substituent in the structure, namely the bridging linker, can be obtained.

[0024] As a further embodiment of the present invention, the elastomer is SEBS or SBS; the chain extender is hydroquinone dihydroxyethyl ether; the antioxidant is at least one of antioxidant BHT, antioxidant 168 or antioxidant 1010; and the lubricant is any one of polyethylene wax, paraffin or calcium stearate.

[0025] Beneficial effects of the present invention:

[0026] The present invention modifies the surface of quartz fiber with a macromolecular substance to produce a modified quartz fiber, which is used as an additive for PET to modify the PET. Because the macromolecular substance contains carboxyl substituents from the L-lysine structure, these carboxyl substituents can participate in the chain extension process of PET, thereby generating strong interweaving between the macromolecular substance and the PET molecular chains, promoting uniform dispersion of the quartz fiber and forming a cross-linked network with the quartz fiber as the cross-linking core. The quartz fiber can utilize its own advantages to quickly disperse and transfer stress loads when the composite material is subjected to external impact or tension, resulting in the composite material being able to exhibit excellent mechanical properties. In addition, the macromolecular substance structure contains a rigid benzonorbornane alternating heterocyclic structure, which can greatly improve the stability of the PET molecular chain. Combined with the presence of the cross-linked network, the composite material can also exhibit excellent high-temperature resistance.

[0027] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 This is the infrared analysis test diagram of the bridging linker. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0031] Example 1

[0032] A polymer composite material for making a plastic housing of an electrical appliance, comprising the following raw materials measured in parts by weight:

[0033]

[0034] The preparation method of the polymer composite material comprises the following steps:

[0035] The first step is to weigh each raw material according to the weight to complete the material preparation;

[0036] In the second step, PET, chain extender hydroquinone dihydroxyethyl ether, and modified quartz fiber were heated and dried, and then placed in a torque rheometer with the temperature controlled at 260°C and the screw speed at 50 rpm. After 3 hours, the material was cooled and discharged to form a precursor material;

[0037] The third step is to add the precursor, elastomer SEBS, microcrystalline cellulose, antioxidant BHT and lubricant polyethylene wax into the mixing kettle, start stirring, set the stirring rate to 300r / min, the temperature to 100℃, stir and mix evenly, and then feed the mixture into the twin-screw extruder through the feeding port for melt extrusion.

[0038] Example 2

[0039] A polymer composite material for making a plastic housing of an electrical appliance, comprising the following raw materials measured in parts by weight:

[0040]

[0041] The preparation method of the polymer composite material comprises the following steps:

[0042] The first step is to weigh each raw material according to the weight to complete the material preparation;

[0043] In the second step, PET, chain extender hydroquinone dihydroxyethyl ether, and modified quartz fiber were heated and dried, and then placed in a torque rheometer with the temperature controlled at 280°C and the screw speed at 50 rpm. After 2 hours, the material was cooled and discharged to form a precursor material.

[0044] The third step is to add the precursor, elastomer SBS, microcrystalline cellulose, antioxidant 168 and lubricant paraffin into the mixing kettle, start stirring, set the stirring rate to 400r / min, the temperature to 120℃, stir and mix evenly, and then feed the mixture into the twin-screw extruder through the feeding port for melt extrusion.

[0045] Example 3

[0046] A polymer composite material for making a plastic housing of an electrical appliance, comprising the following raw materials measured in parts by weight:

[0047]

[0048] The preparation method of the polymer composite material comprises the following steps:

[0049] The first step is to weigh each raw material according to the weight to complete the material preparation;

[0050] In the second step, PET, chain extender hydroquinone dihydroxyethyl ether, and modified quartz fiber were heated and dried, and then placed in a torque rheometer with the temperature controlled at 280°C and the screw speed at 60 rpm. After 3 hours, the material was cooled and discharged to form a precursor material;

[0051] The third step is to add the precursor, elastomer SBS, microcrystalline cellulose, antioxidant 1010 and lubricant polyethylene wax into the mixing kettle, start stirring, set the stirring rate to 500r / min, the temperature to 120℃, stir and mix evenly, and then feed the mixture into the twin-screw extruder through the feeding port for melt extrusion.

[0052] The modified quartz fiber in the above embodiment is prepared by the following method:

[0053] Step S1, dispersing 3 g of quartz fiber in an ethanol medium, and adding 1.2 g of 3-chloropropyltriethoxysilane to the resulting dispersion, then stirring at 65° C. for 6 h, cooling and discharging, to obtain an organic quartz fiber;

[0054] Step S2, add 2.4g of organic quartz fiber to N,N-dimethylformamide, control the ultrasonic frequency to 100kHz, after ultrasonic treatment for 30min, add 1.5g of L-lysine, after the addition, raise the temperature to 65°C, stir for 6h, continue to add 2.2g of bridging connector and 20mL of 10% mass fraction of sodium hydroxide solution, after the addition, further raise the temperature to 85°C, stir for 18h, stop heating, cool the material, separate and collect the solid material.

[0055] The specific preparation method of the bridging linker is as follows:

[0056] Add 0.2 g of 3,6-dihydroxybenzonorbornane and acetone to a reactor filled with nitrogen. After the addition, start stirring. After mixing evenly, place in an ice bath environment. Then, continue to add 0.26 g of chloroacetyl chloride and 0.01 g of pyridine to the reactor. After the addition is complete, remove the ice bath, stir at room temperature for 4 hours, remove the nitrogen, evaporate the solvent, and purify the collected product to obtain a bridging connector.

[0057] The bridging agent was subjected to infrared analysis test, and the results are shown in Figure 1 , of which 3000cm -1 ~3100cm -1 The characteristic absorption peak of CH, which belongs to the benzene ring skeleton in benzonorbornene, appeared at 1728 cm -1 The C=O characteristic absorption peak belonging to the ester group appeared at 740 cm -1 The characteristic absorption peak attributed to C-Cl appeared at Figure 1 There is no obvious hydroxyl characteristic absorption peak.

[0058] Comparative Example 1

[0059] A polymer composite material for making a plastic housing of an electrical appliance, comprising the following raw materials measured in parts by weight:

[0060]

[0061]

[0062] The preparation method of the polymer composite material comprises the following steps:

[0063] The first step is to weigh each raw material according to the weight to complete the material preparation;

[0064] In the second step, PET, chain extender hydroquinone dihydroxyethyl ether, and quartz fiber are heated and dried, and then placed in a torque rheometer with the temperature controlled at 280°C and the screw speed at 50 rpm. After 2 hours, the material is cooled and discharged to form a precursor material;

[0065] The third step is to add the precursor, elastomer SBS, microcrystalline cellulose, antioxidant 168 and lubricant paraffin into the mixing kettle, start stirring, set the stirring rate to 400r / min, the temperature to 120℃, stir and mix evenly, and then feed the mixture into the twin-screw extruder through the feeding port for melt extrusion.

[0066] Comparative Example 2

[0067] A polymer composite material for making a plastic housing of an electrical appliance, comprising the following raw materials measured in parts by weight:

[0068]

[0069]

[0070] The preparation method of the polymer composite material comprises the following steps:

[0071] The first step is to weigh each raw material according to the weight to complete the material preparation;

[0072] In the second step, PET and chain extender hydroquinone dihydroxyethyl ether were heated and dried, and then placed in a torque rheometer, with the temperature controlled at 280°C and the screw speed at 50 rpm. After 2 hours, the material was cooled and discharged to form a precursor material;

[0073] The third step is to add the precursor, elastomer SBS, microcrystalline cellulose, antioxidant 168 and lubricant paraffin into the mixing kettle, start stirring, set the stirring rate to 400r / min, the temperature to 120℃, stir and mix evenly, and then feed the mixture into the twin-screw extruder through the feeding port for melt extrusion.

[0074] Test Case

[0075] The composite materials in the examples and comparative examples were made into test specimens that met the specifications and were subjected to performance tests. The results are recorded in Table 1:

[0076] Table 1 - Test results

[0077] <![CDATA[Impact strength / kJ / m 2 > Tensile strength / MPa Time / h Example 1 15.4 104.3 ＞72 Example 2 15.7 104.8 ＞72 Example 3 15.6 104.6 ＞72 Comparative Example 1 12.2 92.9 ＜24 Comparative Example 2 8.9 69.1 ＜24

[0078] The impact strength is tested according to the standard GB / T 1843-2008;

[0079] Tensile strength is tested according to standard GB / T1040.1-2018;

[0080] The high temperature resistance test method is: place the sample in a temperature environment of 180°C and observe the time required for aging phenomena such as softening, yellowing, and cracking to appear on its surface. Generally speaking, the longer the time, the better the high temperature resistance, and vice versa.

[0081] From the test results, it can be reasonably inferred that although the use of unmodified quartz fiber can have a positive effect on the mechanical strength of PET to a certain extent, due to dispersion problems, some agglomeration phenomena make it unable to effectively exert its excellent performance, so the reinforcement effect is limited. Moreover, after the loss of macromolecular substances, the cross-linked network and rigid heterocycles no longer exist, resulting in poor high-temperature resistance of the material.

[0082] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal description of the claims, or if they include equivalent structural elements that are not substantially different from the literal description of the claims, then these other embodiments should also be included in the scope of the claims.

[0083] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A polymer composite material for making plastic housings of electrical appliances, characterized in that: Contains the following raw materials measured in parts by weight:

2. The polymer composite material for making a plastic housing of an electrical appliance according to claim 1, characterized in that: The preparation method of the polymer composite material comprises the following steps: The first step is to weigh each raw material according to the weight to complete the material preparation; The second step is to heat and dry the PET, chain extender, and modified quartz fiber, and then place them in a torque rheometer, control the temperature to 260-280°C, and the screw speed to 50-60rpm. After 1-3 hours, cool down and discharge the material to form a precursor material; The third step is to add the precursor, elastomer, microcrystalline cellulose, antioxidant and lubricant into the mixing kettle, start stirring, set the stirring rate to 300-500r / min, the temperature to 100-120℃, stir and mix evenly, and then feed the mixture into the twin-screw extruder through the feeding port for melt extrusion.

3. The polymer composite material for making a plastic housing of an electrical appliance according to claim 1, characterized in that: The specific preparation method of the modified quartz fiber comprises the following steps: Step S1: In an ethanol medium, quartz fiber is modified using a silane coupling agent to obtain an organic quartz fiber; Step S2, adding organic quartz fiber to N,N-dimethylformamide, controlling the ultrasonic frequency to 100-120kHz, ultrasonically treating for 20-40min, then adding L-lysine, after the addition is completed, raising the temperature to 60-70°C, stirring for 4-8h, and then continuing to add the bridging connector and acid binding agent. After the addition is completed, the temperature is further raised to 80-90°C, stirring for 12-24h, stopping heating, cooling the material, and separating and collecting the solid material.

4. The polymer composite material for making a plastic housing of an electrical appliance according to claim 3, characterized in that: In step S1, the silane coupling agent is any one of 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane or 3-bromopropyltrimethoxysilane.

5. The polymer composite material for making a plastic housing of an electrical appliance according to claim 3, characterized in that: In step S2, the specific preparation method of the bridging linker is as follows: Add 3,6-dihydroxybenzonorbornane and acetone to a reactor filled with nitrogen, start stirring after the addition, mix evenly, and place in an ice bath environment. Then continue to add the halogenated compound and catalyst to the reactor. After the addition is completed, remove the ice bath, stir at room temperature for 3-6 hours, remove the nitrogen, evaporate the solvent, and purify the collected product to obtain a bridging connector.

6. The polymer composite material for making a plastic housing of an electrical appliance according to claim 5, characterized in that: The molar ratio of the 3,6-dihydroxybenzonorbornane to the halogenated compound is 1:

2.

7. The polymer composite material for making a plastic housing of an electrical appliance according to claim 5, characterized in that: The halogenated compound is chloroacetyl chloride, bromoacetyl bromide or 4-bromobutyryl chloride.

8. The polymer composite material for making a plastic housing of an electrical appliance according to claim 5, characterized in that: The catalyst is pyridine or triethylamine.

9. The polymer composite material for making a plastic housing of an electrical appliance according to claim 3, characterized in that: In step S2, the acid binding agent is a sodium hydroxide solution with a mass fraction of 10-15%.

10. The polymer composite material for making a plastic housing of an electrical appliance according to claim 1, characterized in that: The elastomer is SEBS or SBS; the chain extender is hydroquinone dihydroxyethyl ether; the antioxidant is at least one of antioxidant BHT, antioxidant 168 or antioxidant 1010; and the lubricant is any one of polyethylene wax, paraffin or calcium stearate.

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