A pet resin composition, and a method of preparing and using the same

Abstract

The application belongs to the technical field of engineering plastics, and particularly relates to the field of ultrasonic welding PET compositions, and discloses a PET resin composition which comprises the following components: 60-75 parts of PET resin, 5-15 parts of PETG resin, 2-5 parts of a toughening agent, 18-25 parts of glass fiber, and 0.2-0.8 parts of a nucleating agent. The application provides a PET composition with high ultrasonic welding strength, so that the integrity and overall strength of a PET product after ultrasonic welding are improved, and the cracking and separation of the welding position can be effectively avoided. The PET resin composition of the application is applied to a PET resin material product which needs to be ultrasonically welded, and the related product prepared by the PET resin composition has excellent ultrasonic welding strength and excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of engineering plastics technology, and particularly relates to a PET composition for ultrasonic welding and its preparation method. Background Technology

[0002] Polyethylene terephthalate (PET), also known as polyethylene terephthalate or PEIT, is a major type of thermoplastic polyester, commonly called polyester resin. It is produced by transesterification of dimethyl terephthalate with ethylene glycol or by esterification of terephthalic acid with ethylene glycol to synthesize diethyl terephthalate, followed by polycondensation.

[0003] The main modifications to PET include reinforcement modification and flame retardant reinforcement modification. Among them, reinforced PET products are used in the personal care small appliance industry, such as hair dryers, hair stylists, and flat nozzles. These products require materials with good mechanical properties such as tensile strength and impact strength to meet the functional tests of the products, such as not cracking in drop tests.

[0004] For some PET products, ultrasonic welding is commonly used for assembly and joining. Ultrasonic welding relies on ultrasonic welding technology, a method that melts and bonds the contact surfaces of two objects through high-frequency vibration. Applying this welding method requires the reinforced modified PET product to have high ultrasonic welding strength to ensure that the ultrasonically welded product does not disintegrate.

[0005] The existing technology lacks a PET composition with high ultrasonic welding strength. The PET resin composition provided by the present invention can improve the integrity and overall strength of PET products after ultrasonic welding, and can effectively prevent cracking and disintegration at the weld. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned technical problems and provide a PET resin composition with high ultrasonic welding strength, so as to improve the integrity and overall strength of ultrasonic welding of PET products and avoid cracking and disintegration at the ultrasonic weld.

[0007] Another object of the present invention is to provide a method for preparing the above-described PET resin composition.

[0008] Another object of the present invention is to provide the application of the above-described PET resin composition.

[0009] This invention is achieved through the following technical solution:

[0010] A PET resin composition, comprising the following components in parts by weight:

[0011] 60-75 parts of PET resin;

[0012] 5-15 parts of PETG resin;

[0013] 2-5 parts toughening agent;

[0014] 18-25 parts glass fiber;

[0015] Nucleating agent 0.2-0.8 parts;

[0016] The PET resin contains isophthalic acid, and the weight percentage of isophthalic acid in the PET resin is 1-2%.

[0017] The nucleating agent is a compound of sodium lignite and talc in a weight ratio of (2-4):(6-8);

[0018] The absolute value of the intrinsic viscosity difference between PET resin and PETG resin is less than 0.13 dL / g.

[0019] Preferably, the intrinsic viscosity of the PET resin is 0.68-1.0 dL / g.

[0020] Preferably, the weight percentage content of isophthalic acid in PET resin is 1.3-1.5%.

[0021] Preferably, the intrinsic viscosity of the PETG resin is 0.70-0.86 dL / g, and the viscosity testing standard is ISO1628-5-2015.

[0022] Preferably, the monomer molar percentage of the PETG resin is PTA (terephthalic acid): EG (ethylene glycol): CHDM (1,4-cyclohexanediethanol) in a ratio of 10:(7-5):(3-5).

[0023] More preferably, the monomer molar percentage of the PETG resin is PTA (terephthalic acid): EG (ethylene glycol): CHDM (1,4-cyclohexanediethanol) in a ratio of 2:1:1.

[0024] Preferably, the toughening agent is selected from any one or more of ethylene-butyl acrylate-glycidyl methacrylate terpolymer or ethylene-methyl acrylate-glycidyl methacrylate terpolymer.

[0025] Preferably, the melt index of the ethylene-butyl acrylate-glycidyl methacrylate terpolymer is 5-12 g / 10 min (190℃ / 2.16 kg), and the test method is ISO 1133-1-2022.

[0026] Preferably, the melt index of the ethylene-methyl acrylate-glycidyl methacrylate terpolymer is 5-12 g / 10 min (190℃ / 2.16 kg), and the test method is ISO 1133-1-2022.

[0027] Preferably, the glass fiber is alkali-free glass fiber, and the diameter of the alkali-free glass fiber is 10-13 μm and the length is 3.0-4.5 mm.

[0028] Preferably, the nucleating agent is a compound of sodium lignite and talc in a weight ratio of (2.5-3.5):(6.5-7.5).

[0029] Preferably, by weight, it further comprises: 0.2-0.8 parts of a lubricant, wherein the lubricant is selected from any one or more of pentaerythritol ester or oxidized polyethylene wax.

[0030] The present invention provides a method for preparing the above-mentioned PET resin composition, characterized by comprising the following steps:

[0031] S1: Add all components except glass fiber into a high-speed mixer according to the formula and mix for 2-5 minutes to obtain a premix;

[0032] S2: The premixed material is added to the twin-screw extruder through the main feed port, and the glass fiber is added to the twin-screw extruder through the side feed port according to the formula.

[0033] S3: Melt at 220-270℃. The temperatures of each screw barrel from the feed port to the die head in the twin-screw extruder are 220-240℃, 230-250℃, 230-250℃, 230-250℃, 240-260℃, 240-260℃, 240-260℃, 250-270℃, 250-270℃, 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. After extrusion, the PET resin composition is obtained by cooling and granulation.

[0034] The present invention also provides the application of the above-described PET resin composition for the preparation of products requiring ultrasonic welding.

[0035] The present invention has the following beneficial effects:

[0036] This invention optimizes the isophthalic acid (IPA) content in PET to reduce material crystallization, which is beneficial for ultrasonic welding and improves ultrasonic welding strength. Introducing a PETG resin of a specific viscosity into the system as an ultrasonic welding agent reduces the crystallinity of the PET material, resulting in lower energy requirements and higher energy transfer efficiency during welding, thus improving ultrasonic welding strength.

[0037] By optimizing the viscosity of PET and PETG, the ultrasonic welding strength was effectively improved. It is speculated that the reason may be that the viscosity of PET and PETG is similar, and the large difference in viscosity will not cause uneven distribution of PET and PETG in the material, thus reducing the ultrasonic welding strength.

[0038] By optimizing the toughening agent content, high ultrasonic welding strength can be obtained while ensuring material toughness. If the toughening agent content is too low, the material toughness is poor. If the toughening agent content is too high, higher impact strength can be obtained, but the transmitted vibration energy of ultrasonic waves will be strongly absorbed, thereby reducing the welding strength.

[0039] By employing a compound nucleating agent system, materials can achieve higher ultrasonic welding strength. Using sodium lignite alone requires a large amount, and as sodium lignite is a sodium salt, it degrades PET resin, reducing system viscosity. Furthermore, without talc as inorganic nucleation sites, the material's bulk strength is low, thus reducing ultrasonic welding effectiveness. Using talc alone provides inorganic nucleation sites, but the difficulty of molecular chain movement in PET also leads to a decrease in the material's bulk strength, affecting ultrasonic welding strength. Detailed Implementation

[0040] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0041] The raw materials used in this invention are sourced from:

[0042] PET resin 1: PET BG80, intrinsic viscosity 0.80 dL / g, IPA content 1.3-1.5%, Sinopec Yizheng Chemical Fiber Co., Ltd.

[0043] PET resin 2: PET CR-8828, intrinsic viscosity 0.87 dL / g, IPA content 1.5~2.0%, China Resources Chemical Technology Co., Ltd.

[0044] PET resin 3: PET CR-8863, intrinsic viscosity 0.80 dL / g, IPA content 1.6-2.0%, China Resources Chemical Technology Co., Ltd.

[0045] PET resin 4: PET CR-8839, intrinsic viscosity 0.80 dL / g, IPA content 0.2-0.5%, China Resources Chemical Technology Co., Ltd.

[0046] PET Resin 5: PET CR-7702, intrinsic viscosity 0.5 dL / g, IPA content 1.3-1.5%, China Resources Chemical Technology Co., Ltd.

[0047] PET Resin 6: PET CR-8818, intrinsic viscosity 0.81 dL / g, IPA content 3~4%, China Resources Chemical Technology Co., Ltd.

[0048] PET resin 7: PET FG600, intrinsic viscosity 0.68 dL / g, IPA content 0%, Sinopec Yizheng Chemical Fiber Co., Ltd.

[0049] PETG Resin 1: AKOLYT™ KM 900, intrinsic viscosity 0.74-0.78 dL / g, Selenis Portugal, SA.

[0050] PETG resin 2: Eastar 6763, intrinsic viscosity 0.7-0.74 dL / g, Eastman.

[0051] PETG Resin 3: PETG CR-5511, intrinsic viscosity of 0.79-0.81 dL / g, China Resources Chemical Technology Co., Ltd.

[0052] PETG Resin 4: FLOW™ 65, intrinsic viscosity 0.63-0.67 dL / g, Selenis Portugal, SA.

[0053] PETG Resin 5: GEO™ LF 451, intrinsic viscosity 1.1-1.2 dL / g, Selenis Portugal, SA.

[0054] Toughening agent 1: Elvaloy resins PTW, ethylene-butyl acrylate-glycidyl methacrylate, DuPont.

[0055] Toughening agent 2: Lotader AX8900, ethylene-methyl acrylate-glycidyl methacrylate, Arkema.

[0056] Toughening agent 3: ELVALOY AC RESIN 1125, ethylene methyl acrylate copolymer, DuPont.

[0057] Glass fiber: ECS11-4.5-534A, alkali-free glass fiber, diameter 11um, length 4.5mm, China Jushi Co., Ltd.

[0058] Sodium lignite: LICOMONT NAV101 PWD, Guangzhou Fengtian Chemical Co., Ltd.

[0059] Sodium stearate: Gaomi Xinwei Additives Co., Ltd.

[0060] Talc powder: HTPULTRA5L, Liaoning Aihaiyimi Mining Co., Ltd.

[0061] Lubricant 1: PETS-AP Pentaerythritol Tetrastearate, Faji Asia Pacific Pte Ltd.

[0062] Lubricant 2: Licowax PED 521, oxidized polyethylene wax, Clariant.

[0063] Test methods:

[0064] Ultrasonic welding strength: The material is injection molded into welding specimens at 270℃. The upper and lower specimens are placed in the positioning limit blocks in the ultrasonic welding machine, and the welding pressure is set to 2 kg / cm². 2 The ultrasonic welding process was performed with a welding time of 0.4 s and a hardening time of 0.4 s. After welding, the tensile strength was tested using a universal tensile testing machine at a tensile rate of 10 mm / min to characterize the ultrasonic weld strength.

[0065] Table 1. Weight parts and test results of each component in the PET resin compositions of Examples 1-7:

[0066] PET resin 1 60 70 66 66 66 PET resin 2 65 75 PETG resin 1 5 8 12 15 10 10 10 Toughening agent 1 2 4 3 3 3 Toughening agent 2 3 5 Fiberglass 18 20 22 25 20 20 20 Sodium lignite 0.05 0.12 0.2 0.24 0.1 0.15 0.2 talcum powder 0.15 0.28 0.4 0.56 0.4 0.35 0.3 Lubricant 1 0.2 0.6 0.5 0.5 0.5 Lubricant 2 0.4 0.8 Ultrasonic welding strength (N) 680 700 760 745 750 755 740

[0067] As can be seen from Examples 5-7, the nucleating agent is compounded from sodium lignite and talc in a weight ratio of (2-4):(6-8). When the weight ratio of sodium lignite and talc is preferably (2.5-3.5):(6.5-7.5), the PET resin composition has better ultrasonic welding strength.

[0068] Table 2. Weight parts of each component and test results of PET resin compositions in Examples 8-10

[0069] PET resin 1 66 66 PET resin 3 66 PETG resin 1 10 PETG resin 2 10 PETG resin 3 10 Toughening agent 1 3 3 3 Fiberglass 20 20 20 Sodium lignite 0.15 0.15 0.15 talcum powder 0.35 0.35 0.35 Lubricant 1 0.5 0.5 0.5 Ultrasonic welding strength (N) 720 735 785

[0070] As can be seen from Examples 6 and 8, the preferred isophthalic acid weight percentage content is 1.3-1.5%, and PET with added isophthalic acid within this content range can achieve better ultrasonic welding strength.

[0071] As can be seen from Examples 6 / 9-10, the smaller the absolute value of the difference in intrinsic viscosity between PET resin and PETG resin, the higher the ultrasonic welding strength of the PET resin composition.

[0072] Table 3. Weight parts of each component and test results of PET resin compositions in Comparative Examples 1-6:

[0073] PET resin 1 66 66 PET resin 4 66 PET resin 5 66 PET resin 6 66 PET resin 7 66 PETG resin 1 10 10 10 10 PETG resin 4 10 PETG resin 5 10 Toughening agent 1 3 3 3 3 3 3 Fiberglass 20 20 20 20 20 20 Sodium lignite 0.15 0.15 0.15 0.15 0.15 0.15 talcum powder 0.35 0.35 0.35 0.35 0.35 0.35 Lubricant 1 0.5 0.5 0.5 0.5 0.5 0.5 Ultrasonic welding strength (N) 150 260 100 230 400 210

[0074] As shown in Comparative Examples 1-3, the absolute value of the intrinsic viscosity difference between PET resin and PETG resin is greater than or equal to 0.13 dL / g, resulting in a significant reduction in ultrasonic welding strength. The likely reason is that the large viscosity difference between PET and PETG leads to uneven distribution of PET and PETG in the material, thus reducing the ultrasonic welding strength.

[0075] As can be seen from Comparative Examples 4-6, the content of isophthalic acid exceeding the range of 1-2% will lead to a decrease in ultrasonic welding strength if the content of isophthalic acid is too low or too high.

[0076] Table 4. Weight parts and test results of each component in the PET resin composition of Comparative Example 7-11:

[0077] PET resin 1 66 66 66 66 66 PETG resin 1 10 10 20 10 10 Toughening agent 1 7 3 3 Toughening agent 3 3 Fiberglass 1 20 20 20 20 20 Sodium lignite 0.15 0.15 0.15 0.15 Sodium stearate 0.15 talcum powder 0.35 0.35 0.35 0.35 0.35 Lubricant 1 0.5 0.5 0.5 0.5 0.5 Ultrasonic welding strength (N) 520 233 130 420 380

[0078] As shown in Comparative Examples 7-8, exceeding 2-5 parts by weight of toughening agent will have a certain impact on ultrasonic welding strength. Compared with Example 6, Comparative Example 7 shows that the ultrasonic welding strength of the PET resin composition decreased to some extent without the addition of toughening agent. Comparative Example 8 added 7 parts by weight of toughening agent, exceeding the specified range, resulting in a decrease in the ultrasonic welding strength of the PET resin composition.

[0079] As shown in Comparative Example 9, adding excessive PETG resin also causes a significant decrease in the ultrasonic welding strength of the PET resin composition.

[0080] As shown in Comparative Example 10, the choice of toughening agent has an impact on the strength of ultrasonic welding.

[0081] As shown in Comparative Example 11, using sodium stearate instead of sodium lignite as a nucleating agent in combination with talc has an impact on the ultrasonic welding strength.

Claims

1. A PET resin composition, characterized in that, By weight, it contains the following components: 60-75 parts of PET resin; 5-15 parts of PETG resin; 2-5 parts toughening agent; 18-25 parts glass fiber; Nucleating agent 0.2-0.8 parts; The PET resin contains isophthalic acid, and the weight percentage of isophthalic acid in the PET resin is 1-2%. The nucleating agent is a compound of sodium lignite and talc in a weight ratio of (2-4):(6-8); The absolute value of the intrinsic viscosity difference between PET resin and PETG resin is less than 0.13 dL / g; The toughening agent is selected from any one or more of ethylene-butyl acrylate-glycidyl methacrylate terpolymer or ethylene-methyl acrylate-glycidyl methacrylate terpolymer.

2. The PET resin composition according to claim 1, characterized in that, The intrinsic viscosity of the PET resin is 0.68-1.0 dL / g.

3. The PET resin composition according to claim 1, characterized in that, The weight percentage content of isophthalic acid in PET resin is 1.3-1.5%.

4. The PET resin composition according to claim 1, characterized in that, The intrinsic viscosity of the PETG resin is 0.70-0.86 dL / g.

5. A PET resin composition according to claim 1, characterized in that, The glass fiber is alkali-free glass fiber with a diameter of 10-13 μm and a length of 3.0-4.5 mm.

6. The PET resin composition according to claim 1, characterized in that, The nucleating agent is a compound of sodium lignite and talc in a weight ratio of (2.5-3.5):(6.5-7.5).

7. The PET resin composition according to claim 1, characterized in that, By weight, it also contains the following components: 0.2-0.8 parts of a lubricant selected from pentaerythritol ester or oxidized polyethylene wax.

8. A method for preparing the PET resin composition according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Add all components except glass fiber into a high-speed mixer according to the formula and mix for 2-5 minutes to obtain a premix; S2: The premixed material is added to the twin-screw extruder through the main feed port, and the glass fiber is added to the twin-screw extruder through the side feed port according to the formula. S3: Melt at 220-270℃. The temperatures of each screw barrel from the feed port to the die head in the twin-screw extruder are 220-240℃, 230-250℃, 230-250℃, 230-250℃, 240-260℃, 240-260℃, 240-260℃, 250-270℃, 250-270℃, 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. After extrusion, the PET resin composition is obtained by cooling and granulation.

9. The application of the PET resin composition according to any one of claims 1-7, characterized in that, Used to manufacture products that require ultrasonic welding.