A pet composition, and a method of making and using the same

Abstract

The application discloses a PET composition and a preparation method and application thereof, and belongs to the technical field of engineering plastics. The PET composition has good tin solder resistance, high toughness and high fluidity, and is suitable for preparing electronic and electrical products, such as coil skeletons, by selecting a homopolymer PET resin as a base resin, adding a first tin solder-resistant ethylene copolymer ionomer and a second tin solder-resistant specific ether ester type plasticizer, and controlling the content of each component within a specific range.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engineering plastics, in particular to a PET composition and a preparation method and application thereof. BACKGROUND

[0002] Polyethylene terephthalate (PET) is a semi-crystalline thermoplastic polyester. The modification of PET mainly includes reinforcing modification and flame-retardant reinforcing modification. The flame-retardant reinforcing modification PET product is often applied in the electronic and electrical industry (such as coil framework, shell, etc.), and the material is required to meet the tin soldering resistance requirement so as to be used for connecting with metal parts. The material is also required to have high toughness to meet the functional test of the product. Meanwhile, the material is required to have high flowability to meet the requirement of injection molding. Therefore, it is necessary to develop a PET material which has the properties of tin soldering resistance, high toughness and high flowability. SUMMARY

[0003] Based on the defects of the prior art, the purpose of the present application is to provide a PET composition and a preparation method and application thereof, which aims to make the PET material have the properties of tin soldering resistance, high toughness and high flowability.

[0004] In order to achieve the above-mentioned purpose, in the first aspect, the present application provides a PET composition comprising the following components by weight:

[0005]

[0006] The first tin soldering resistance agent is an ethylene copolymer ionomer;

[0007] The second tin soldering resistance agent is an ether ester type plasticizer, including at least one of the compounds of formula I,

[0008]

[0009] wherein R1 and R2 are each independently C7-C9 alkyl, and n is an integer less than 7;

[0010] The PET resin is a homopolymer PET resin.

[0011] Conventional flame-retardant reinforced modified PET materials have poor solderability, and the solder joints are prone to blackening, resulting in a high defect rate. This application selects homopolymer PET resin as the matrix resin because homopolymer PET resin has zero isophthalic acid (IPA) content, resulting in better crystallinity compared to copolymer PET resin, thus improving the crystallinity of the material system. Simultaneously, a first solder-resistant flux, ethylene copolymer ionomer, is added as a nucleation site for heterogeneous nucleation. The ethylene copolymer ionomer contains EAA units (i.e., ethylene-acrylic acid units) and metal ions, with the metal ions serving as nucleation centers. The carboxyl groups of the EAA units react with the terminal hydroxyl groups in the PET resin, promoting nucleation of the PET resin towards the metal ions. The center migration can significantly improve the crystallinity of the material system. Additionally, a second solder-resistant ether ester plasticizer is added. This ether ester plasticizer has a specific structure, an n-value below 7, a low molecular weight, good compatibility with PET resin, and is easily dispersed in PET resin. Furthermore, the ether bonds and ester groups it contains have hydrogen bonding interactions with the ester groups and hydroxyl groups in PET resin, which greatly enhances the mobility of PET molecular chains. This allows PET molecular chains to align more quickly towards nucleation sites, increasing the degree of crystallinity of the system. Under the synergistic effect of a specific content of homopolymer PET resin, a first solder-resistant ethylene copolymer ionomer, and a second solder-resistant ether ester plasticizer, the PET composition of this application exhibits high crystallinity, good high-temperature resistance, strong resistance to solder blackening, and a low defect rate in soldered products.

[0012] The content of the first solder-resistant flux ethylene copolymer ionomer and toughening agent affects the material's fluidity. By controlling their content within the specific ranges mentioned above, they can effectively improve crystallinity or toughness while ensuring high material fluidity.

[0013] The PET composition of this application, under the combined action of the above-mentioned components in specific amounts, not only has good solderability but also high toughness and high flowability.

[0014] Preferably, n is an integer from 2 to 7. For example, n is 2, 3, 4, 5, 6, or 7.

[0015] Preferably, the melt flow rate (melt flow rate, i.e., melt index) of the first solder-resistant flux at a temperature of 190°C and a load of 2.16 kg is 0.7-15 g / 10 min. More preferably, the melt flow rate of the first solder-resistant flux at a temperature of 190°C and a load of 2.16 kg is 4-6 g / 10 min.

[0016] When the melt flow rate of the first solder-resistant flux at a temperature of 190℃ and a load of 2.16kg is in the range of 0.7-15g / 10min, especially in the range of 4-6g / 10min, the material exhibits stronger resistance to solder blackening and a lower defect rate in soldered products. The melt flow rate of the first solder-resistant flux at a temperature of 190℃ and a load of 2.16kg can be selected from any two of the following ranges: 0.7g / 10min, 0.8g / 10min, 0.9g / 10min, 1g / 10min, 2g / 10min, 3g / 10min, 4g / 10min, 5g / 10min, 6g / 10min, 7g / 10min, 8g / 10min, 9g / 10min, 10g / 10min, 11g / 10min, 12g / 10min, 13g / 10min, 14g / 10min, 15g / 10min, or any two of the above values.

[0017] The melt flow rate of the first tin-resistant flux was measured in accordance with ISO 1133-1:2011.

[0018] Preferably, the cation in the first solder-resistant flux is at least one selected from sodium ions, calcium ions, and zinc ions. More preferably, the cation in the first solder-resistant flux is zinc ions. When the cation in the first solder-resistant flux is zinc ions, the material has a stronger resistance to solder blackening, and the defect rate of soldered products is lower.

[0019] Preferably, the intrinsic viscosity of the PET is 0.6-0.9 dL / g.

[0020] The intrinsic viscosity of PET is closely related to its processing performance and mechanical properties (such as cantilever beam notched impact strength). Controlling the intrinsic viscosity of PET within the above-mentioned range results in better overall performance of the material in terms of processing performance and mechanical properties (such as cantilever beam notched impact strength).

[0021] The intrinsic viscosity of PET was tested using the capillary viscometer method (method A, 5.1.1) in GB / T 14190-2017, with phenol and 1,1,2,2-tetrachloroethane (mass ratio 50:50) as the solvents.

[0022] Preferably, the toughening agent includes at least one of ethylene-butyl acrylate-glycidyl methacrylate terpolymer and ethylene-methyl acrylate-glycidyl methacrylate terpolymer.

[0023] The type of toughening agent affects the flowability of the material. When at least one of ethylene-butyl acrylate-glycidyl methacrylate terpolymer or ethylene-methyl acrylate-glycidyl methacrylate terpolymer is used as a toughening agent, the toughness of the material can be improved to a greater extent with a smaller amount added, while ensuring better flowability.

[0024] Preferably, the content of glycidyl methacrylate (GMA) in the ethylene-butyl acrylate-glycidyl methacrylate terpolymer is 3-8 wt.%.

[0025] Preferably, the content of glycidyl methacrylate (GMA) in the ethylene-methyl acrylate-glycidyl methacrylate terpolymer is 3-8 wt.%.

[0026] Preferably, the glass fiber is alkali-free glass fiber with a diameter of 10-13 μm and a length of 3.0-4.5 mm.

[0027] Preferably, it further includes the following components in parts by weight:

[0028] Antioxidant 0.2-0.5 parts,

[0029] Lubricant 0.5-1.2 parts.

[0030] Preferably, the flame retardant includes at least one of brominated polystyrene and brominated epoxy resin.

[0031] Preferably, the antioxidant includes at least one of hindered phenols (pentaerythritol ester), phosphites, and thioethers.

[0032] Preferably, the lubricant includes at least one of pentaerythritol ester and oxidized polyethylene wax.

[0033] Preferably, the PET resin in the PET composition has a mass fraction of 44% or more, such as a range of 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, or more.

[0034] Secondly, this application provides a method for preparing the PET composition, comprising the following steps: mixing raw materials other than glass fiber and feeding them into a twin-screw extruder through the main feed port, and feeding glass fiber into the twin-screw extruder through the side feed port, melting and extruding, cooling and granulating to obtain the PET composition.

[0035] Preferably, the melt extrusion meets the following requirements: temperature 220-270℃, screw speed 250-400 rpm, feed rate 50-200 kg / h, and vacuum degree -0.1~0 MPa. More preferably, the barrel temperature of the twin-screw extruder from the main feed inlet to the die head is sequentially: 220-240℃, 230-250℃, 230-250℃, 230-250℃, 240-260℃, 240-260℃, 240-260℃, 250-270℃, 250-270℃, and 250-270℃.

[0036] Thirdly, this application provides the use of the PET composition in the preparation of coil frames.

[0037] Compared with the prior art, the beneficial effects of this application are as follows:

[0038] (1) The PET composition of this application has higher crystallinity, higher high temperature resistance, stronger resistance to solder blackening and lower defect rate of solder products by selecting homopolymer PET resin as the matrix resin and adding first solder-resistant ethylene copolymer ionomer and second solder-resistant ether ester plasticizer.

[0039] (2) The PET composition of this application, under the combined action of each component in a specific amount, has good solderability, high toughness and high fluidity, and is suitable for the preparation of electronic and electrical products, such as coil bobbins. Detailed Implementation

[0040] To better illustrate the purpose, technical solutions, and advantages of this application, the following description, in conjunction with specific embodiments and comparative examples, aims to provide a detailed understanding of the content of this application, rather than limiting it. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this application are commonly used reagents and instruments. In this application, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0041] The raw materials used in the following embodiments and comparative examples are shown in Table 1, and unless otherwise specified, all raw materials are commercially available. Furthermore, the same raw materials were used in each parallel experiment.

[0042] Table 1

[0043]

[0044]

[0045] The melt index of 0.9g / 10min@190℃ / 2.16kg in Table 1 refers to the melt index being 0.9g / 10min under the test conditions of 190℃ and 2.16kg load. Other similar statements are interpreted in the same way.

[0046] The following examples and comparative examples all provide a PET composition, comprising the following steps: mixing raw materials other than glass fiber and feeding them into a twin-screw extruder through the main feed inlet, and feeding glass fiber into the twin-screw extruder through the side feed inlet; melt extruding; cooling and granulating to obtain the PET composition, wherein the melt extrusion satisfies:

[0047] The barrel temperatures of the twin-screw extruder from the main feed inlet to the die head are as follows: 220-240℃, 230-250℃, 230-250℃, 230-250℃, 240-260℃, 240-260℃, 240-260℃, 250-270℃, 250-270℃, and 250-270℃. The screw speed is 250-400 rpm, the feed rate is 50-200 kg / h, and the vacuum degree is -0.1~0 MPa.

[0048] The formulations of these examples and comparative PET compositions are shown in Tables 2 and 3.

[0049] Table 2

[0050]

[0051]

[0052] Table 3

[0053] Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 PET resin 1 52 50 52 50 46 56 51 51 First tin-resistant flux 3 1 3 2 2 2 2 2 2 Second tin-resistant flux 1 2 2 1 3 2 2 2 2 Toughener 1 1 1 1 1 1 1 0.5 2 Flame retardant 13 13 13 13 13 13 15 10 Glass fiber 30 30 30 30 35 25 28.5 31.6 Antioxidant 0.3 0.3 0.3 0.3 0.3 0.3 0 0.2 Lubricant 0.7 0.7 0.7 0.7 0.7 0.7 0 1.2

[0054] The above embodiments and comparative examples were subjected to the following performance tests, and the test results are shown in Table 4.

[0055] Soldering defect rate: After drying the material at 120℃ for 4 hours, 100 skeleton products were injection molded. Soldering tests were performed on these skeleton products. If the soldered parts did not turn black, they were qualified; otherwise, they were unqualified and defective. The defect rate was calculated.

[0056] DSC (Differential Scanning Calorimetry) crystallization temperature: After drying the material at 120℃ for 4 hours, it is injection molded into a standard curved strip. 8mg of material is cut from the curved strip and placed in a crucible to make a standard test sample. The test is conducted according to the test standard ISO11357-1:2016. Test conditions: 30-300℃, heating rate 10℃ / min, 1.5°C, N2 atmosphere.

[0057] Cantilever beam notched impact strength: Test standard ISO 180-2019, pendulum energy 2.75J, type A notch.

[0058] Spiral length: Set the injection temperature to 270 degrees Celsius, use a spiral mold, and inject a spiral under the same injection molding process conditions to test the spiral length.

[0059] Table 4

[0060]

[0061]

[0062] The data above show that the materials in each embodiment possess good solderability, high toughness, and high fluidity. For example, the DSC crystallization temperature is above 220°C, the solder defect rate is below 3%, and the cantilever beam notched impact strength is 9 kJ / m. 2 The spiral length is above 210mm.

[0063] Comparative Example 1, without the addition of ethylene copolymer ionomer, had a lower degree of material crystallinity and a higher rate of solder defective products.

[0064] Comparative Example 2, which did not contain ether ester plasticizers, had a lower degree of crystallinity and a higher rate of soldering defects.

[0065] Comparative Example 3, without the addition of toughening agent, showed lower notched impact strength of the cantilever beam.

[0066] In Comparative Example 4, the amount of ethylene copolymer ionomer added was excessive. Since it contains ethylene copolymer and has a structure similar to the toughening agent, the excessive ethylene copolymer structure will lead to a decrease in the melt index of the system. At the same time, it is ionized, which has no effect on the toughening of the system. On the contrary, the presence of excessive ions will reduce the cantilever beam notched impact strength of the system.

[0067] In Comparative Example 5, the amount of ether ester plasticizer added was excessive. Ether ester plasticizers mainly improve the mobility of PET molecular chains. When the content of ether ester plasticizer is too high, the excess part does not improve the mobility of PET molecular chains, but will reduce the viscosity of the system (improve fluidity), thus resulting in a lower cantilever beam notched impact strength of the material.

[0068] In Comparative Example 6, the excessive addition of toughening agent hindered material flow, resulting in a lower helix length.

[0069] The PET resin used in Comparative Example 7 was a copolymer PET resin, which had poor crystallinity, resulting in a lower material crystallization temperature and a higher soldering defect rate.

[0070] The n-value of the ether ester plasticizer used in Comparative Example 8 was too high, resulting in excessively high viscosity and difficulty in dispersing in the system. This made it difficult to effectively disperse in the PET resin, thus affecting its ability to improve the activity of PET molecular chains, leading to a lower crystallization temperature and a higher soldering defect rate.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A PET composition, characterized in that, Includes the following components by weight: 46-56 parts of PET resin First, 1-3 parts of solder-resistant flux. 1-3 parts of the second solder-resistant flux, Toughening agent 0.5-2 parts, 10-15 parts flame retardant 25-35 parts glass fiber; The first solder-resistant flux is an ionomer of ethylene copolymer; The second solder-resistant flux is an ether ester type plasticizer, including at least one of the compounds of formula I. Formula I, Wherein, R1 and R2 are each independently C7-C9 alkyl groups, and n is an integer from 2 to 7; The PET resin is a homopolymer PET resin.

2. The PET composition according to claim 1, characterized in that, The first tin-resistant flux has a melt flow rate of 0.7-15 g / 10 min at a temperature of 190°C and a load of 2.16 kg.

3. The PET composition according to claim 2, characterized in that, The first tin-resistant flux has a melt flow rate of 4-6 g / 10 min at a temperature of 190°C and a load of 2.16 kg.

4. The PET composition according to claim 1, characterized in that, The cation in the first tin-resistant flux is at least one of sodium ion, calcium ion, and zinc ion.

5. The PET composition according to claim 4, characterized in that, The cation in the first tin-resistant flux is zinc ion.

6. The PET composition according to claim 1, characterized in that, The intrinsic viscosity of the PET is 0.6-0.9 dL / g.

7. The PET composition according to claim 1, characterized in that, The toughening agent includes at least one of ethylene-butyl acrylate-glycidyl methacrylate terpolymer and ethylene-methyl acrylate-glycidyl methacrylate terpolymer.

8. The PET composition according to claim 1, characterized in that, At least one of the following conditions must be met: S1. The glass fiber is alkali-free glass fiber with a diameter of 10-13 μm and a length of 3.0-4.5 mm; The flame retardant S2 includes at least one of brominated polystyrene and brominated epoxy resin; S3 also contains the following components in parts by weight: Antioxidant 0.2-0.5 parts, Lubricant 0.5-1.2 parts, The antioxidant includes at least one of hindered phenols, phosphites, and thioethers. The lubricant includes at least one of pentaerythritol ester and oxidized polyethylene wax.

9. The method for preparing the PET composition according to any one of claims 1 to 8, characterized in that, The process includes the following steps: mixing raw materials other than glass fiber and feeding them into a twin-screw extruder through the main feed port, and feeding glass fiber into the twin-screw extruder through the side feed port, melting and extruding, cooling and granulating to obtain the PET composition.

10. The method for preparing the PET composition according to claim 9, characterized in that, The melt extrusion meets the following requirements: temperature 220-270℃, screw speed 250-400 rpm, feed rate 50-200 kg / h, and vacuum degree -0.1~0 MPa.

11. The use of the PET composition according to any one of claims 1 to 8 in the preparation of coil frames or housings.

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