Modified PET (Polyethylene Terephthalate) material as well as preparation method and application thereof

Abstract

The invention discloses a modified PET material as well as a preparation method and application thereof. The modified PET material comprises the following components in parts by mass: 70-85 parts of a PET matrix; 6-15 parts of a composite monomer; and 1-3 parts of an auxiliary agent. Wherein the composite monomer comprises an alcohol oligomer and epoxy resin, the composite monomer is introduced into the alcohol oligomer and is copolymerized with a PET molecular chain in a PET matrix, so that the rigidity of the molecular chain can be reduced, the flexibility of PET is increased, meanwhile, due to the addition of the epoxy resin, on one hand, the heat resistance of the PET material can be ensured, and on the other hand, the heat resistance of the PET material is improved. The epoxy resin can be subjected to a grafting reaction in the presence of the auxiliary agent, so that the epoxy resin is grafted to PET molecular chains in a PET matrix, entanglement among the molecular chains is enhanced, the interface bonding capacity is improved, the compatibility of the composite monomer and the PET matrix is improved, the flexibility of the modified PET material is kept, and meanwhile, the mechanical property can be considered.

Description

Technical Field

[0001] The present invention relates to the field of PET technology, and in particular to a modified PET material, a preparation method and application thereof. Background Art

[0002] Polyethylene terephthalate (PET) is a widely used thermoplastic polyester material. It is widely used in textiles, beverage bottles, food packaging and industrial applications due to its good mechanical strength, chemical resistance, heat resistance and molding processability. However, with the development of industrial technology and the increase in application demand, ordinary PET materials have gradually exposed some performance deficiencies, especially in some high-end application scenarios. PET materials are more rigid and brittle, and have poor impact resistance, which limits their wide application in the field of high-performance structural materials.

[0003] With the advancement of science and technology, electronic equipment, home appliances and the automotive industry have increasingly higher performance requirements for structural materials. For example, mobile phone shells and home appliance shells require materials to have high impact resistance, scratch resistance and thermal stability, and also require materials to have good processing performance and surface finish. However, existing PET materials and modification technologies are unable to cope with these high requirements. For example, PET materials tend to become brittle at low temperatures, have low impact strength, and cannot meet high toughness requirements. In addition, due to the high crystallinity of PET materials, they are prone to large shrinkage and rough surface during the molding process, making it difficult to meet high-precision processing requirements.

[0004] In order to meet the high requirements for materials in electronic equipment casings, home appliance components, etc., it is of great significance to develop a modified PET material that has high strength, good toughness and heat resistance. Summary of the invention

[0005] The main purpose of the present invention is to propose a modified PET material, a preparation method and an application, aiming to solve the problem in the prior art that PET materials tend to become brittle during processing, have low impact strength, and cannot meet high toughness requirements and high-precision processing requirements.

[0006] To achieve the above object, the present invention provides a modified PET material, comprising the following components in parts by weight:

[0007] PET matrix 40-50 parts;

[0008] 1 to 3 parts of a composite monomer; and

[0009] 1 to 3 parts of additives;

[0010] Wherein, the composite monomer comprises alcohol oligomer and epoxy resin, the alcohol oligomer is alcohol oligomer, and the epoxy resin is epoxy resin.

[0011] In some embodiments, the mass ratio of the alcohol oligomer to the epoxy resin is (1-2); 1.

[0012] In some embodiments, the epoxy resin includes at least one of bisphenol A type epoxy resin E51, epoxy resin E54, and epoxy resin E42.

[0013] In some embodiments, the auxiliary agent includes an initiator, a catalyst, an accelerator, and a curing agent.

[0014] In some embodiments, the PET matrix includes terephthalic acid and ethylene glycol; and / or, the alcohol oligomer includes PEG, PTMG or adipic acid.

[0015] In some embodiments, the catalyst comprises an antimonate, a titanate or a tin-based catalyst; and / or,

[0016] The initiator comprises dibenzoyl peroxide; and / or,

[0017] The promoter comprises maleic anhydride; and / or,

[0018] The curing agent includes a tertiary amine curing agent or triethylamine.

[0019] In some embodiments, in the auxiliary agent, the mass ratio of the initiator, the catalyst, the accelerator and the curing agent is (1-5): (0.1-0.5): (0.5-2): (1-5).

[0020] Another aspect of the present invention provides a method for preparing a modified PET material, comprising the following steps:

[0021] Mixing the PET matrix with the alcohol oligomer to obtain a PET prepolymer;

[0022] The PET prepolymer, epoxy resin and auxiliary agent are blended, modified and cooled to obtain the modified PET material.

[0023] In some embodiments, the step of blending and modifying the PET prepolymer with an auxiliary agent and cooling to obtain the modified PET material comprises: the cooling temperature is 25 to 35°C.

[0024] The present invention also provides an application of the modified PET material as described above, which is used for electronic equipment housings or household appliances.

[0025] In the technical solution of the present invention, the modified PET material includes a PET matrix, a composite monomer and an auxiliary agent, wherein the composite monomer is introduced into an alcohol oligomer and is copolymerized with the PET molecular chain in the PET matrix, thereby reducing the rigidity of the molecular chain and increasing the flexibility of the PET. At the same time, the addition of the epoxy resin can, on the one hand, ensure the heat resistance of the PET material, and on the other hand, the epoxy resin can undergo a grafting reaction in the presence of the auxiliary agent, thereby grafting the epoxy resin onto the PET molecular chain in the PET matrix, enhancing the entanglement between the molecular chains and improving the interface bonding ability, thereby improving the compatibility of the composite monomer with the PET matrix, maintaining the flexibility of the modified PET material while taking into account the mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 the structures shown in these drawings without paying creative work.

[0027] Figure 1 This is a flow chart for preparing the modified PET material provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] To make the purpose, technical scheme and advantages of the embodiment of the present invention clearer, the technical scheme in the embodiment of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiment, it is carried out according to the normal conditions or the conditions recommended by the manufacturer. If the reagents or instruments used do not specify the manufacturer, they are all conventional products that can be purchased commercially. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes, taking "A and / or B" as an example, including scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, the technical schemes between the various embodiments can be combined with each other, but must be based on the ability of ordinary technicians in the field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that the combination of such technical solutions does not exist, and is not within the scope of protection required by the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present invention.

[0029] With the advancement of science and technology, electronic equipment, home appliances and the automotive industry have increasingly higher performance requirements for structural materials. For example, mobile phone shells and home appliance shells require materials to have high impact resistance, scratch resistance and thermal stability, and also require materials to have good processing performance and surface finish. However, existing PET materials and modification technologies are unable to cope with these high requirements. For example, PET materials tend to become brittle at low temperatures, have low impact strength, and cannot meet high toughness requirements. In addition, due to the high crystallinity of PET materials, they are prone to large shrinkage and rough surface during the molding process, making it difficult to meet high-precision processing requirements.

[0030] In order to meet the high requirements for materials in electronic equipment casings, home appliance components, etc., it is of great significance to develop a modified PET material that has high strength, good toughness and heat resistance.

[0031] In view of this, an embodiment of the present invention provides a modified PET material, comprising the following components in parts by weight:

[0032] PET matrix 40-50 parts;

[0033] 1 to 3 parts of a composite monomer; and

[0034] 1 to 3 parts of additives;

[0035] Wherein, the composite monomer comprises alcohol oligomer and epoxy resin, the alcohol oligomer is alcohol oligomer, and the epoxy resin is epoxy resin.

[0036] In the technical solution of the present invention, the modified PET material includes a PET matrix, a composite monomer and an auxiliary agent, wherein the composite monomer is introduced into an alcohol oligomer and is copolymerized with the PET molecular chain in the PET matrix, thereby reducing the rigidity of the molecular chain and increasing the flexibility of the PET. At the same time, the addition of the epoxy resin can, on the one hand, ensure the heat resistance of the PET material, and on the other hand, the epoxy resin can undergo a grafting reaction in the presence of the auxiliary agent, thereby grafting the epoxy resin onto the PET molecular chain in the PET matrix, enhancing the entanglement between the molecular chains and improving the interface bonding ability, thereby improving the compatibility of the composite monomer with the PET matrix, maintaining the flexibility of the modified PET material while taking into account the mechanical properties.

[0037] It should be noted that polyethylene terephthalate (PET) is a polyester engineering plastic. PET is formed by the polycondensation reaction of ethylene glycol and terephthalic acid. It is a linear macromolecule with a symmetrical benzene ring structure and orderly arranged functional groups. Each unit is connected by an ester group. The rigid components and flexible components on the molecular chain give it good performance.

[0038] In some embodiments, the mass ratio of the alcohol oligomer to the epoxy resin is (1-2):1. Such a ratio achieves a good balance between the rigidity of the epoxy resin and the flexibility of the alcohol oligomer, ensuring that the material has high strength, can withstand the impact and deformation of external forces, and maintains a certain flexibility.

[0039] In some embodiments, the epoxy resin includes at least one of bisphenol A type epoxy resin E51, epoxy resin E54 and epoxy resin E42. It should be noted that epoxy resin, as a high-performance thermosetting material, is gradually being used in the modification of PET materials due to its excellent mechanical properties and chemical stability. Bisphenol A type epoxy resin, especially E51, E54 and E42 type epoxy resins, has a high cross-linking density and can effectively improve the strength and rigidity of PET. Different types of epoxy resins can adjust the mechanical properties, thermal stability and chemical stability of the material, so that the modified PET material has high mechanical strength, heat resistance and wear resistance, which is particularly suitable for the needs of electronic equipment housings.

[0040] In some embodiments, the auxiliary agent includes an initiator, a catalyst, an accelerator, and a curing agent.

[0041] The rate and effect of the entire reaction process can be adjusted by adding additives such as initiators, catalysts, accelerators and curing agents. Initiators promote the reaction between epoxy resin and PET matrix, catalysts accelerate polycondensation, accelerators further increase the reaction rate, and curing agents ensure that epoxy resin forms a stable solid structure under low temperature conditions. The addition of additives can significantly increase the degree of polymerization and crosslinking density of the material, optimize the reaction conditions, and ensure that the material has good mechanical properties and stability after curing.

[0042] In some embodiments, the PET matrix includes terephthalic acid and ethylene glycol. The PET matrix can be made by yourself using the above materials or can be directly purchased to provide raw materials for modified PET materials.

[0043] The alcohol oligomer includes PEG, PTMG or adipic acid. The alcohol oligomer is a flexible monomer. Its introduction can change the structure of the PET molecular chain and give the modified PET material better flexibility. Adipic acid is preferred because it is easier to obtain and has a better effect.

[0044] In some embodiments, the catalyst includes antimonate, titanate or tin catalyst to adjust the reaction rate, making the preparation process more efficient and controllable.

[0045] The initiator includes dibenzoyl peroxide, which is mainly used to promote the grafting reaction between maleic anhydride and epoxy resin, and the initiator dibenzoyl peroxide guides the copolymerization reaction between epoxy resin and PET. The accelerator includes maleic anhydride, which promotes the cross-linking reaction. The curing agent such as tertiary amines or triethylamine helps to cure the epoxy resin at low temperature. The curing agent includes tertiary amine curing agent or triethylamine, which can be cured during the epoxy resin addition and blending process. At this time, a cross-linking structure will be introduced during the curing process to improve the mechanical properties of the material.

[0046] In some embodiments, among the auxiliary agents, the mass ratio of the initiator, the catalyst, the promoter and the curing agent is (1-5): (0.1-0.5): (0.5-2): (1-5). The above ratio allows the auxiliary agent to be within a suitable ratio range, which neither wastes the auxiliary agent nor promotes the modification of the PET matrix to obtain a modified PET material with both flexibility and mechanical properties.

[0047] In some embodiments, the present invention provides a method for preparing a modified PET material, such as Figure 1 As shown, specifically including:

[0048] Mixing the PET matrix with the alcohol oligomer to obtain a PET prepolymer;

[0049] The PET prepolymer, epoxy resin and auxiliary agent are blended, modified and cooled to obtain the modified PET material.

[0050] In the preparation method proposed by the present invention, a PET matrix is ​​first mixed with an alcohol oligomer to obtain a PET prepolymer, and a flexible monomer is introduced to reduce the rigidity of the molecular chain, thereby increasing the flexibility of PET. Then, epoxy resin and an auxiliary agent are added to the PET prepolymer, mixed evenly, and a grafting reaction occurs, and grafting is performed on the PET molecular chain of the PET prepolymer to obtain the modified PET material. The modified PET material prepared by the two-step blending process of the present invention can reduce stress concentration, and the dispersed phase size of the obtained blending system is the smallest and the distribution is uniform, and the impact strength is the largest and the toughness is the best; in addition, the modified PET material prepared by the preparation method proposed by the present invention has all the beneficial effects of the above-mentioned modified PET material, which will not be described one by one here.

[0051] In some embodiments, the steps of blending and modifying the PET prepolymer and the auxiliary agent, and cooling the mixture to obtain the modified PET material include:

[0052] The PET prepolymer is blended with the additive and cooled to 25-35° C. to obtain the modified PET material. After the mixing reaction, the material is cooled to a specific temperature to ensure that the epoxy resin is cured and the material is transformed from a liquid or gel state to a solid state. This step is crucial to ensure the terminal mechanical properties of the material.

[0053] It should be noted that the cooling process controls the solidification and crystallization behavior of the material, ensuring that the physical properties of the modified PET, such as strength, toughness, and heat resistance, reach the optimal state.

[0054] In another aspect, the present invention provides the application of modified PET materials for electronic equipment housings or household appliances. Specifically, the application of the modified PET materials in electronic equipment housings and household appliances is mainly used as a material directly used to manufacture the housings and some internal structural parts of these products. For example, as a housing material, modified PET materials are often used in the housings of electronic equipment and household appliances because they have strength, toughness and durability. Through different modification processes, such as adding glass fiber, reinforcing agent, flame retardant, etc., it can meet different usage requirements.

[0055] Specific applications include: Electronic device housings: such as laptops, smartphones, tablets, cameras, etc. These housings require both lightness and durability, and modified PET provides good impact resistance and abrasion resistance.

[0056] Household appliance shells: such as washing machines, refrigerators, coffee machines, hair dryers, microwave ovens, etc. Modified PET materials are resistant to high temperatures and chemical corrosion, and are easy to shape, making them suitable for mass production.

[0057] In addition to the outer shell, modified PET is also widely used in some internal structural parts of home appliances and electronic equipment, such as: insulating parts in electrical appliances: due to the good insulation properties of PET, after modification, it is still suitable for use in support parts, circuit board bases, etc. in electronic equipment, which can isolate electronic components and prevent short circuits.

[0058] In summary, modified PET material, as a high-quality engineering plastic, can be directly used as the shell material of electronic equipment and household appliances, and can also be used in internal structures and functional components, combining functionality and decoration.

[0059] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0060] Example 1

[0061] This embodiment provides a modified PET material, which includes the following components:

[0062] PET substrate 7.5Kg, adipic acid 1Kg, epoxy resin E42 5Kg, antimonate catalyst 0.125Kg, dibenzoyl peroxide 0.75Kg, maleic anhydride 0.125Kg, triethylamine 1Kg;

[0063] Wherein, the preparation steps of the modified PET material are as follows:

[0064] The PET matrix and oxalic acid are subjected to an esterification reaction at normal pressure and 180° C. to generate a low-polyester, and the low-polyester is then reacted at 270° C. and 1 mmHg for about 3 hours to perform a polycondensation reaction, and ethylene glycol is continuously discharged by vacuum distillation to prepare a PET prepolymer;

[0065] The PET prepolymer is mixed with the epoxy resin, antimonate catalyst, dibenzoyl peroxide, maleic anhydride and triethylamine to obtain a reactant, and the reactant is cooled to obtain a modified PET material.

[0066] Example 2

[0067] Except for the different ratios of specific components from Example 1, the rest is similar to Example 1. This Example 2 provides a modified PET material, which includes the following components: 8.5Kg of PET matrix, 10Kg of adipic acid, 5Kg of epoxy resin E42, 0.187Kg of antimonate catalyst, 1.125Kg of dibenzoyl peroxide, 0.187Kg of maleic anhydride, and 1.5Kg of triethylamine.

[0068] Example 3

[0069] Except for the different ratios of specific components from Example 1, the rest is similar to Example 1. This Example 3 provides a modified PET material, which includes the following components: 7Kg of PET matrix, 2Kg of adipic acid, 1Kg of epoxy resin E42, 0.06Kg of antimonate catalyst, 0.375Kg of dibenzoyl peroxide, 0.06Kg of maleic anhydride, and 0.5Kg of triethylamine.

[0070] Example 4

[0071] Except for the different ratios of specific components from Example 1, the rest is similar to Example 1. This Example 4 provides a modified PET material, which includes the following components: 7Kg of PET matrix, 3Kg of adipic acid, 1Kg of epoxy resin E42, 0.125Kg of antimonate catalyst, 0.75Kg of dibenzoyl peroxide, 0.125Kg of maleic anhydride, and 1Kg of triethylamine.

[0072] Comparative Example 1

[0073] This comparative example is similar to Example 1, and its preparation process is similar to Example 1, except that the epoxy resin is removed and the composite monomer is only an alcohol oligomer.

[0074] Comparative Example 2

[0075] This comparative example is similar to Example 1, and its preparation process is similar to Example 1, except that the alcohol oligomer is removed and the composite monomer is only epoxy resin.

[0076] Performance Testing

[0077] The PET materials prepared in the examples and comparative examples were processed into test samples. Each group of test samples was tested 5 times, and the average value was taken as the final test result, which is as follows:

[0078] (1) Bending strength: According to the test standard of GB / T 9431-2008, the test sample was prepared into a rectangular sample with a size of 80 mm*10 mm*4 mm and tested using a three-point bending test machine;

[0079] (2) Tensile strength: The test specimens were prepared into dumbbell-shaped tensile specimens with a thickness of 4 mm and a length of 150 mm. The test was performed using a universal material testing machine in accordance with the test standard GB / T 1040.2-2006.

[0080] (3) Impact strength: The test specimens were prepared into rectangular strips with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm. The test was performed according to the test standard of ISO 179. The test results are shown in Table 1.

[0081] Table 1

[0082]

[0083]

[0084] The test results are shown in Table 1:

[0085] From the tensile strength point of view: Example 2 has the highest tensile strength, reaching 70MPa. This is because the introduction of appropriate amounts of epoxy resin E42 and alcohol oligomers, the rigid structure of the epoxy resin improves the overall tensile properties of the material; in contrast, Comparative Examples 1 and 2 lack one of the composite monomers, resulting in a weakened force between the molecular chains, and thus lower tensile strength. In particular, Comparative Example 1, the epoxy resin is removed, lacking the rigid component that strengthens the material structure, resulting in a significant decrease in tensile strength.

[0086] In terms of bending strength, Example 2 also performs best, reaching 95 MPa. This is because the introduction of epoxy resin forms a relatively uniform cross-linked network structure inside the material, which enhances the material's ability to resist deformation under bending load; the bending strengths of Comparative Examples 1 and 2 are significantly lower than those of Examples 1-4, especially Comparative Example 1, which lacks the cross-linking effect of epoxy resin, resulting in insufficient bearing capacity under bending load.

[0087] From the perspective of impact strength, in the impact strength test, the result of Example 2 is 14.45 kJ / m 2 , which performs best. This is due to the reasonable ratio of composite monomers (alcohol oligomers and epoxy resin); the impact strength of Example 3 is slightly lower, which may be due to the low content of epoxy resin and the insufficient density of the cross-linked structure. The impact strength of Comparative Examples 1 and 2 is significantly lower, especially Comparative Example 1, which lacks the support of the rigid network structure after removing the epoxy resin, causing the material to break easily under impact load.

[0088] In summary, by introducing appropriate amounts of epoxy resin and alcohol oligomers, and combining the reasonable ratio of antimonate catalyst, peroxidation initiator and promoter, the modified PET material has significantly improved tensile strength, flexural strength and impact strength, especially Example 2 shows the best comprehensive performance. This material is suitable for high-performance application scenarios, such as mobile phone housings and home appliance parts, and can meet higher requirements for material toughness, strength and impact resistance.

[0089] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A modified PET material, characterized in that: The composition comprises the following components in parts by weight: PET matrix 70-85 parts; 6 to 15 parts of a composite monomer; and 1 to 3 parts of additives; Wherein, the composite monomer includes alcohol oligomer and epoxy resin.

2. The modified PET material according to claim 1, characterized in that: The mass ratio of the alcohol oligomer to the epoxy resin is (1-2):

1.

3. The modified PET material according to claim 1, characterized in that: The epoxy resin includes at least one of bisphenol A type epoxy resin E51, epoxy resin E54 and epoxy resin E42.

4. The modified PET material according to claim 1, characterized in that: The auxiliary agents include initiators, catalysts, accelerators and curing agents.

5. The modified PET material according to claim 1, characterized in that: The PET matrix comprises terephthalic acid and ethylene glycol; and / or, The alcohol oligomer includes PEG, PTMG or adipic acid.

6. The modified PET material according to claim 4, characterized in that: The catalyst comprises an antimonate catalyst, a titanate catalyst or a tin catalyst; and / or, The initiator comprises dibenzoyl peroxide; and / or, The promoter comprises maleic anhydride; and / or, The curing agent includes a tertiary amine curing agent or triethylamine.

7. The modified PET material according to claim 4, characterized in that: In the auxiliary agent, the mass ratio of the initiator, the catalyst, the accelerator and the curing agent is (1-5): (0.1～0.5)：(0.5～2)：(1～5)。 8. A method for preparing the modified PET material according to any one of claims 1 to 5, characterized in that: The following steps are involved: Mixing the PET matrix with the alcohol oligomer to obtain a PET prepolymer; The PET prepolymer, epoxy resin and auxiliary agent are blended, modified and cooled to obtain the modified PET material.

9. The preparation method according to claim 8, characterized in that: The steps of blending and modifying the PET prepolymer, epoxy resin and auxiliary agent, and cooling to obtain the modified PET material include: The cooling temperature is 25-35°C.

10. Use of the modified PET material according to any one of claims 1 to 7 or the modified PET material prepared by the method for preparing the modified PET material according to claim 8 or 9, characterized in that: The modified PET material is used for electronic equipment housings or household appliances.

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