CN117820824A - Modified PET composite material and its preparation method and application - Google Patents

Abstract

The present application provides a modified PET composite material and its preparation method and application, the material includes: 80-95 parts of polyethylene terephthalate, 5-20 parts of polycarbonate, 0.2-1 parts of light diffuser, 2-8 parts of toughening agent, 0.2-2 parts of compatibilizer, 0.05-2 parts of nucleating agent, 0.05-2 parts of lubricant, 0.05-2 parts of antioxidant, 0.1-1 parts of pigment. The preparation method of the modified PET composite material provided by the present application, by mixing PET and PC and adding a toughening agent, can optimize the performance of PET and PC, obtain better heat resistance, rigidity and toughness, solve the problem of deformation of PET material when heated, and also maintain the light transmittance of the material. The refrigerator lampshade prepared by the modified PET composite material solves the problem of deformation of the refrigerator lampshade when heated, and can be better assembled with the claws on the box shell.

Description

Modified PET composite material and its preparation method and application

Technical Field

The present application relates to the field of polymer materials, and in particular to a modified PET composite material and a preparation method and application thereof.

Background technique

The internal lighting of refrigerators is usually protected by lampshades, which are generally made of transparent materials. The light source can be covered by surface texture or light diffusers to make the light softer. There are four kinds of materials for refrigerator lampshades, among which general purpose polystyrene (GPPS) is the most widely used in lampshades due to its high light transmittance and low price. The other three materials are transparent ABS plastic (AcrylonitrileButadieneStyrene plastic), polycarbonate (PC) and K resin. These three materials have better toughness than GPPS, but their prices are relatively high, which limits their promotion and use in lampshades.

Due to the convenience of assembly and maintenance needs, the lampshade has a claw structure to facilitate installation and disassembly. Among the materials used, GPPS has good rigidity but poor toughness. During the disassembly of the lampshade, the claw often breaks, and the market defect rate is high. Transparent ABS, PC and K resin have good toughness and can improve the problem of lampshade claw breaking during disassembly, but the price is high and accounts for a very low proportion in the use of lampshades.

In order to solve the problems of the above four materials, polyethylene terephthalate (PET) can be used as the material of the lampshade. PET is a material with high transparency and good toughness, and the material price is low, but PET has slightly poor heat resistance. The lampshade of the refrigerator is a universal part. Export products are generally transported by sea. The temperature of the container is high in summer. If PET is used directly to make the refrigerator lampshade, it is likely to deform due to heat resistance.

Summary of the invention

The present application provides a modified PET composite material and a preparation method and application thereof, so as to solve the problem that the PET material is deformed when heated.

In a first aspect, the present application provides a modified PET composite material, the components of which are measured by weight: 80-95 parts of polyethylene terephthalate, 5-20 parts of polycarbonate, 0.2-1 parts of a light diffuser, 2-8 parts of a toughening agent, 0.2-2 parts of a compatibilizer, 0.05-2 parts of a nucleating agent, 0.05-2 parts of a lubricant, 0.05-2 parts of an antioxidant, and 0.1-1 parts of a pigment.

Optionally, the polyethylene terephthalate has a melt mass flow rate MFR of ≥10 g/10 min at 300° C. and a load of 1.2 kg.

Optionally, the intrinsic viscosity of the polyethylene terephthalate is greater than 0.80 dl.g ^-1 .

Optionally, the light diffuser is an organic silicone resin, and the organic silicone resin is spherical.

Optionally, the toughening agent is any one or more combinations of MBS resin or polyolefin elastomer POE.

Optionally, the compatibilizer is any one or more combinations of maleic anhydride grafted POE or maleic anhydride grafted PE.

Optionally, the lubricant is any one or more combinations of PE wax or zinc stearate.

In a second aspect, the present application provides a method for preparing the PET composite material according to the first aspect, comprising:

Drying the polyethylene terephthalate at 140-150° C. for 4-5 hours to obtain dry polyethylene terephthalate;

The dried polyethylene terephthalate, polycarbonate, light diffuser, toughening agent, compatibilizer, nucleating agent, lubricant, antioxidant and pigment are added into a high-speed mixer and mixed for 3-5 minutes to obtain a mixture;

The mixture is added into a twin-screw extruder and extruded into pellets to obtain a modified PET composite material.

Optionally, the screw temperature range of the feeding section of the twin-screw extruder is 210-230°C, the screw temperature range of the melting section is 270-290°C, and the screw temperature of the homogenizing section is 285°C; the screw speed range of the twin-screw extruder is 20-50rpm/min.

In a third aspect, the present application provides application of the PET composite material described in the first aspect in a refrigerator lamp cover.

The present application provides a modified PET composite material and its preparation method and application, wherein the material comprises: 80-95 parts of polyethylene terephthalate, 5-20 parts of polycarbonate, 0.2-1 parts of light diffuser, 2-8 parts of toughening agent, 0.2-2 parts of compatibilizer, 0.05-2 parts of nucleating agent, 0.05-2 parts of lubricant, 0.05-2 parts of antioxidant, and 0.1-1 parts of pigment. The preparation method of the modified PET composite material provided in the present application can optimize the performance of PET and PC by mixing PET and PC and adding a toughening agent to obtain better heat resistance, rigidity and toughness, solve the problem of deformation of PET material due to heat, and maintain the light transmittance of the material. The refrigerator lampshade prepared by the modified PET composite material solves the problem of deformation of the refrigerator lampshade due to heat, and can be better assembled with the claws on the box shell.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

FIG. 1 is a schematic flow chart of a method for preparing a modified PET composite material.

Detailed ways

The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following embodiments do not represent all implementations consistent with the present application. They are only examples of systems and methods consistent with some aspects of the present application as detailed in the claims.

PET is a material with high transparency and good toughness. It is cheap, but its heat resistance is slightly poor. When PET is used as the material for refrigerator lampshades, since refrigerator lampshades are common parts, export products are generally transported by sea, and the temperature of containers is high in summer, if PET is used directly to make refrigerator lampshades, it is likely to deform due to heat resistance. Therefore, PET needs to be heat-resistant modified to increase the glass transition temperature of PET to meet the use requirements of refrigerator lampshades.

In order to solve the problem of deformation of PET materials when heated, some embodiments of the present application provide a modified PET composite material, whose components, measured by weight, include: 80-95 parts of polyethylene terephthalate, 5-20 parts of polycarbonate, 0.2-1 parts of light diffuser, 2-8 parts of toughening agent, 0.2-2 parts of compatibilizer, 0.05-2 parts of nucleating agent, 0.05-2 parts of lubricant, 0.05-2 parts of antioxidant, and 0.1-1 parts of pigment.

Polyethylene terephthalate (PET) is a crystalline saturated polyester made by ester exchange of dimethyl terephthalate with ethylene glycol or esterification of terephthalic acid with ethylene glycol to synthesize dihydroxyethyl terephthalate, and then polycondensation. PET has high hardness, good dimensional stability, the highest toughness among thermoplastics, low water absorption, but is not resistant to hot water immersion. PET has a high glass transition temperature and slow crystallization rate, so it has low heat resistance.

Polycarbonate PC is a high molecular polymer containing carbonate groups in the molecular chain. It is a tough thermoplastic resin with high strength and elastic coefficient, good heat resistance, good dimensional stability, small creep, and little change under high temperature conditions. It also has high transparency and free dyeing properties. Therefore, in the embodiment of the present application, PC is used to improve the heat resistance of PET. The greater the proportion of PC added, the higher the heat resistance of the PET and PC alloy material. However, the increase in the proportion of PC will affect the molding process, making it difficult to extrude and granulate, and will also increase the material cost. It is necessary to reasonably control the content of PC.

In order to obtain a refrigerator lampshade material with high strength, good toughness and high heat resistance, in some embodiments, the melt mass flow rate MFR of PET at 300°C and 1.2Kg load is ≥10g/10min, and the intrinsic viscosity is >0.80dl.g ^-1 . After blending PET and PC materials, the properties of PET and PC can be optimized to obtain a refrigerator lampshade material with high strength, good toughness and high heat resistance.

During the use of the refrigerator lampshade, in order to provide a better sense of use, make the lampshade have good detachability and resist thermal deformation, its toughness and heat resistance are necessary. In order to obtain a modified PET composite material that is more suitable for a refrigerator lampshade, the various substances are mixed evenly according to the ratio shown in Table 1 to prepare modified PET composite materials of Examples 1-5 and Comparative Examples 1-2 for testing.

Table 1 Modified PET composites with different components

See Table 1. In order to obtain better strength, toughness and heat resistance, experiments were conducted using different types and amounts of materials.

In some embodiments, the light diffuser is an organic silicone resin, which has a three-dimensional cross-linked network molecular structure, excellent heat resistance and dispersion properties, and can be added to plastic materials as a light diffuser to make the base materials, i.e., PET and PC, have light diffusion properties with high haze and high light transmittance. A spherical organic silicone resin can be used as a light diffuser to make the light diffuser more fully mixed with PET and PC.

In order to improve the toughness of the modified PET composite material, in some embodiments, the modified PET composite material further includes a toughening agent. The toughening agent is any one or more combinations of MBS resin or polyolefin elastomer POE, for example: Example 3 is a combination of MBS resin and polyolefin elastomer POE, wherein the MBS resin is 4 parts and the polyolefin elastomer POE is 2 parts. For another example: the toughening agent can be any one of MBS resin and polyolefin elastomer POE, wherein Example 4 and Example 5 respectively select 5 parts of MBS resin and 8 parts of polyolefin elastomer POE.

Different effects will occur due to different parts of the toughening agent in different embodiments. When the toughening agent ratio is as in Embodiment 1, Embodiment 2, Embodiment 3, Embodiment 4 and Embodiment 5, that is, when the part of the toughening agent is 2-8 parts, the toughness of the modified PET composite material is better than the toughness of the modified PET composite material in Comparative Example 1 and Comparative Example 2. In other words, the toughness of the modified polypropylene material with the part of the toughening agent being 2-8 parts is better, and it has nothing to do with the selection of MBS resin or polyolefin elastomer POE. Therefore, in some embodiments, the part of the toughening agent is 2-8 parts.

In order to better adjust and control the microscopic phase structure of PET and PC, thereby achieving high performance and functionalization, in some embodiments, the modified PET composite material also includes a compatibilizer, the number of which is 0.2-2 parts, and the compatibilizer can be any one or more combinations of maleic anhydride grafted POE or maleic anhydride grafted PE. For example: Example 3 is a combination of maleic anhydride grafted POE and maleic anhydride grafted PE, wherein maleic anhydride grafted POE is 0.4 parts and maleic anhydride grafted PE is 0.8 parts. For another example, the compatibilizer can be any one of maleic anhydride grafted POE or maleic anhydride grafted PE, wherein Example 1 and Example 2 choose to add 0.2 parts of maleic anhydride grafted POE and 0.5 parts of maleic anhydride grafted PE respectively.

Maleic anhydride grafted POE or maleic anhydride grafted PE is obtained by reactive extrusion grafting maleic anhydride, which can improve the adhesion and compatibility of the material, and thus improve the toughness of the material. Adding a compatibilizer to the modified PET composite material can improve the adhesion and compatibility of PET and PC, and thus improve the toughness of the material after PET and PC are mixed.

Due to the different refractive indices of PET and PC, the material obtained by simple mixing and granulation will appear opaque or foggy when used as an injection molded product. In order to reduce the difference in refractive indices between PC and PET and improve the transparency of the material, in some embodiments, the modified PET composite material also includes a nucleating agent, and 0.05-2 parts of the nucleating agent are added to PET and PC to increase the crystallization rate and refine the crystal particle size, thereby improving the transparency of the material. The nucleating agent can be a polymer nucleating agent. Since the lampshade used in the refrigerator must meet the food contact grade requirements, and inorganic nucleating agents and organic small molecule nucleating agents are prone to the risk of migration and precipitation when in contact with food, polymer nucleating agents have low volatility during processing and are not easy to migrate in the product. In addition, polymer nucleating agents have better dispersibility, are easy to mix evenly, and have good processing performance.

In some implementations, the modified PET composite material also includes a lubricant, which is used to improve the fluidity of the material and prevent the material from adhering to the screw of the extruder. The number of parts of the lubricant is 0.05-2 parts, and the lubricant is a combination of any one or more of PE wax or zinc stearate. For example: Example 1 is a combination of PE wax and zinc stearate, wherein PE wax is 1.5 parts and zinc stearate is 0.5 parts. For another example, the lubricant can be selected from any one of PE wax and zinc stearate, wherein Example 2 and Example 3 respectively select 1.3 parts of PE wax and 0.8 parts of zinc stearate to be added.

In order to improve the antioxidant performance of the material, in some embodiments, the modified PET composite material also includes an antioxidant, the amount of the antioxidant is 0.05-2 parts, and the antioxidant can be any one or more combinations of antioxidant 1010 or antioxidant 168. For example: Example 2 is a combination of antioxidant 1010 and antioxidant 168, wherein antioxidant 1010 is 0.3 parts and antioxidant 168 is 0.7 parts. For another example: the antioxidant can be any one of antioxidant 1010 and antioxidant 168, wherein Example 1 and Example 5 respectively choose to add 2 parts of antioxidant 1010 and 0.05 parts of antioxidant 168. Antioxidants 1010 and antioxidants 168 have good effects in preventing discoloration caused by light and heat, and can also prevent thermal oxidation aging of the material.

In some embodiments, the modified PET composite material further comprises a pigment to obtain composite materials of different colors, and the number of pigments is 0.1-1. The pigment can be an organic pigment, which has bright colors, is not easy to fade, is more environmentally friendly, and is more suitable for use in refrigerator lampshade materials.

Table 2 Experimental results

The test results of Examples 1-5 and Comparative Examples 1-2 are shown in Table 2. It can be seen from Comparative Examples 1 and 2 in Table 2 that the proportions of PET and PC have an impact on the performance of the composite material. The more the proportions of PC, the higher the glass transition temperature of the composite material and the better the heat resistance; the more the proportions of toughening agent, the higher the notched impact strength of the composite material and the better the toughness. Table 2 also adds the experimental results of GPPS and PET materials, namely Comparative Examples 3 and 4. It can be seen from Comparative Examples 3 and 4 in Table 2 that although the glass transition temperature of the modified PET composite material of Examples 1-5 is lower than that of the GPPS material of Comparative Example 3, it is significantly higher than that of the PET material of Comparative Example 4, that is, the heat resistance of the modified PET composite material is significantly improved. The notched impact strength of the modified PET composite material of Examples 1-5 is significantly improved compared with Comparative Examples 3 and 4, that is, the toughness of the material is significantly improved. At the same time, due to the addition of the nucleating agent, while improving the heat resistance and toughness, a certain degree of transparency is maintained, so that the light transmittance and haze of the modified PET composite material meet the requirements for lampshade use.

Based on the above modified PET composite material, some embodiments of the present application also provide a method for preparing the modified PET composite material, referring to FIG1 , the method comprises:

S100: drying the polyethylene terephthalate at 140-150° C. for 4-5 hours to obtain dry polyethylene terephthalate.

S200: Add dry polyethylene terephthalate, polycarbonate, light diffuser, toughening agent, compatibilizer, nucleating agent, lubricant, antioxidant and pigment into a high-speed mixer and mix for 3-5 minutes to obtain a mixture.

Since polyethylene terephthalate PET and polycarbonate PC have different properties, in order to optimize the performance of the two, PET and PC can be blended first, and then light diffusers, toughening agents, compatibilizers, nucleating agents, lubricants, antioxidants, and pigments are added to a high-speed mixer. Exemplarily, the mixing time of the mixer is 3 minutes, 4 minutes, and 5 minutes.

S300: adding the mixture into a twin-screw extruder, extruding and granulating, and obtaining a modified PET composite material.

In some embodiments, the screw temperature of the feeding section of the twin-screw extruder is between 210-230°C, the screw temperature of the melting section is between 270-290°C, and the screw temperature of the homogenizing section is 285°C; the screw speed of the twin-screw extruder is between 20-50rpm/min. Exemplarily, the temperature of the feeding section of the twin-screw extruder can be 210°C or 220°C, and the screw speed of the twin-screw extruder can be 30rpm/min, 40rpm/min, or 50rpm/min.

It is understandable that, due to the good heat resistance of PC and the addition of a toughening agent to the composite material, the heat resistance and toughness of the modified PET composite material can be improved, so that the refrigerator lampshade prepared by this preparation method has better performance.

Without considering the effects of light diffusers, toughening agents, compatibilizers, nucleating agents, lubricants, antioxidants, and pigments on the modified PET composite material, Example 6 and Comparative Example 5 were used to test the effect of mixing time on the performance of the modified PET composite material.

Example 6, PET, PC, light diffuser, toughening agent, compatibilizer, nucleating agent, lubricant, antioxidant, and pigment are added to a high-speed mixer and blended, wherein the number of PET is 85 parts, the number of PC is 15 parts, and the number of other materials is 10 parts; the mixing time is 3 minutes, and the mixture is added to a twin-screw extruder, extruded and granulated to obtain a modified PET composite material, wherein the screw temperature of the feeding section of the twin-screw extruder is 220°C, the screw temperature of the melting section is 280°C, the screw temperature of the homogenizing section is 285°C, and the screw speed is 40rpm/min.

In comparative example 5, PET, PC, a light diffuser, a toughening agent, a compatibilizer, a nucleating agent, a lubricant, an antioxidant, and a pigment are added to a high-speed mixer and blended, wherein the number of PET is 85 parts, the number of PC is 15 parts, and the number of other materials is 10 parts; the mixing time is 6 minutes, and the mixture is added to a twin-screw extruder, extruded and granulated to obtain a modified PET composite material, wherein the screw temperature of the feeding section of the twin-screw extruder is 220°C, the screw temperature of the melting section is 280°C, the screw temperature of the homogenizing section is 285°C, and the screw speed is 40rpm/min.

The results of the experiment showed that the tensile strength, elongation at break and flexural strength of Comparative Example 5 were all lower than those of Example 6, which means that the blending time would affect the various properties of the modified PET composite material.

Based on the above-mentioned modified PET composite material and its preparation method, some embodiments of the present application also provide the application of the modified PET composite material in a refrigerator lampshade, wherein the modified PET composite material is put into a PET-specific injection molding machine, and a refrigerator lampshade product is obtained by injection molding.

The embodiment of the present application provides a modified PET composite material and its preparation method and application, the materials include: 80-95 parts of polyethylene terephthalate, 5-20 parts of polycarbonate, 0.2-1 parts of light diffuser, 2-8 parts of toughening agent, 0.2-2 parts of compatibilizer, 0.05-2 parts of nucleating agent, 0.05-2 parts of lubricant, 0.05-2 parts of antioxidant, and 0.1-1 parts of pigment. The preparation method of the modified PET composite material provided in the present application can optimize the performance of PET and PC by mixing PET and PC and adding a toughening agent to obtain better heat resistance, rigidity and toughness, solve the problem of deformation of PET material due to heat, and maintain the light transmittance of the material. The refrigerator lampshade prepared by the modified PET composite material solves the problem of deformation of the refrigerator lampshade due to heat, and can be better assembled with the claws on the box shell.

Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.

Claims (10)

1. A modified PET composite material, characterized in that its components, by weight, include: 80-95 parts of polyethylene terephthalate, 5-20 parts of polycarbonate, 0.2-1 parts of light diffusing agent, 2-8 parts of toughening agent, 0.2-2 parts of compatibilizer, 0.05-2 parts of nucleating agent, 0.05-2 parts of lubricant, 0.05-2 parts of antioxidant, and 0.1-1 parts of pigment. 2. The modified PET composite material according to claim 1, characterized in that the melt mass flow rate MFR of the polyethylene terephthalate at 300°C and a load of 1.2 kg is ≥10 g/10 min. 3 . The modified PET composite material according to claim 1 , wherein the intrinsic viscosity of the polyethylene terephthalate is greater than 0.80 dl.g ⁻¹ . 4 . The modified PET composite material according to claim 1 , wherein the light diffusing agent is an organic silicone resin, and the organic silicone resin is spherical. 5. The modified PET composite material according to claim 1, characterized in that the toughening agent is any one or more combinations of MBS resin or polyolefin elastomer POE. 6. The modified PET composite material according to claim 1, characterized in that the compatibilizer is any one or more combinations of maleic anhydride grafted POE or maleic anhydride grafted PE. 7. The modified PET composite material according to claim 1, characterized in that the lubricant is any one or more combinations of PE wax or zinc stearate. 8. The method for preparing the modified PET composite material according to any one of claims 1 to 7, characterized in that it comprises: Drying the polyethylene terephthalate at 140-150° C. for 4-5 hours to obtain dry polyethylene terephthalate; The dried polyethylene terephthalate, polycarbonate, light diffuser, toughening agent, compatibilizer, nucleating agent, lubricant, antioxidant and pigment are added into a high-speed mixer and mixed for 3-5 minutes to obtain a mixture; The mixture is added into a twin-screw extruder and extruded into pellets to obtain a modified PET composite material. 9. The preparation method according to claim 8 is characterized in that the screw temperature range of the feeding section of the twin-screw extruder is 210-230°C, the screw temperature range of the melting section is 270-290°C, and the screw temperature of the homogenizing section is 285°C; the screw speed range of the twin-screw extruder is 20-50rpm/min. 10. Use of the modified PET composite material according to any one of claims 1 to 7 in a refrigerator lampshade.