PET (Polyethylene Terephthalate) resin composition as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of engineering plastics, 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 fibers and 0.2-0.8 part of a nucleating agent.The invention provides a PET composition with high ultrasonic welding strength. The PET resin composition can be used for improving the integrality and the overall strength of a PET product after ultrasonic welding, cracking and separation of a welding position can be effectively avoided, the PET resin composition is applied to a PET resin material product needing ultrasonic welding, and a related product prepared from the PET resin composition has excellent ultrasonic welding strength and is good in ultrasonic welding performance. Meanwhile, excellent mechanical properties are also realized.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering plastics, and in particular relates to a PET composition used in the field of ultrasonic welding and a preparation method thereof. Background Art

[0002] Polyethylene terephthalate (PET), also known as Polyethylene terephthalate, or PET or PEIT for short, is the main type of thermoplastic polyester, commonly known as polyester resin. It is 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.

[0003] The modifications of PET mainly include reinforced modification and flame retardant reinforced modification. Among them, reinforced modified PET products are used in the personal care small appliance industry such as hair dryers, hair dryers, flat nozzles, etc. This type of product requires the material to have good mechanical properties such as tensile strength and impact strength to meet the functional tests of the product, such as no cracking in the drop test.

[0004] For some PET products, ultrasonic welding is usually used for product combination connection and assembly. Ultrasonic welding mainly relies on ultrasonic welding technology, which is a method of melting the contact surface of two objects and combining them through high-frequency vibration. The use of this welding method requires that the reinforced modified PET product has a high ultrasonic welding strength to ensure that the product will not disintegrate after ultrasonic welding.

[0005] The prior art 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 avoid cracking and disintegration at the welding point. Summary of the invention

[0006] The object of the present invention is to solve the above technical problems and provide a PET resin composition with high ultrasonic welding strength to improve the integrity and overall strength of ultrasonic welding of PET products and avoid cracking, disintegration and detachment at ultrasonic welding points.

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

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

[0009] The present invention is achieved through the following technical solutions: A PET resin composition, comprising the following components in parts by weight: PET resin 60-75 parts; PETG resin 5-15 parts; 2-5 parts of toughening agent; Glass fiber 18-25 parts; Nucleating agent 0.2-0.8 parts; The PET resin contains isophthalic acid, and the weight percentage content of the isophthalic acid in the PET resin is: 1-2%; The nucleating agent is prepared by mixing sodium montanate and talc in a weight ratio of (2-4): (6-8); The absolute value of the difference in intrinsic viscosity between PET resin and PETG resin is less than 0.13 dL / g.

[0010] Preferably, the intrinsic viscosity of the PET resin is 0.68-1.0 dL / g.

[0011] Preferably, the weight percentage content of isophthalic acid in the PET resin is: 1.3-1.5%.

[0012] Preferably, the intrinsic viscosity of the PETG resin is 0.70-0.86 dL / g, and the viscosity detection standard is ISO1628-5-2015.

[0013] Preferably, the molar percentage of the monomers of the PETG resin is PTA (terephthalic acid): EG (ethylene glycol): CHDM (1,4-cyclohexanedimethanol) in a ratio of 10: (7-5): (3-5).

[0014] Further preferably, the molar percentage of the monomers of the PETG resin is PTA (terephthalic acid): EG (ethylene glycol): CHDM (1,4-cyclohexanedimethanol) in a ratio of 2:1:1.

[0015] 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.

[0016] Preferably, the melt index of the ethylene-butyl acrylate-glycidyl methacrylate terpolymer is 5-12 g / 10 min (190° C. / 2.16 kg), and the detection method is: ISO 1133-1-2022.

[0017] Preferably, the melt index of the ethylene-methyl acrylate-glycidyl methacrylate terpolymer is 5-12 g / 10 min (190° C. / 2.16 kg), and the detection method is: ISO 1133-1-2022.

[0018] Preferably, the glass fiber is an alkali-free glass fiber, and the diameter of the alkali-free glass fiber is 10-13 um and the length is 3.0-4.5 mm.

[0019] Preferably, the nucleating agent is prepared by mixing sodium montanate and talcum powder in a weight ratio of (2.5-3.5): (6.5-7.5).

[0020] Preferably, the following components are further included by weight: 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.

[0021] The present invention provides a method for preparing the above-mentioned PET resin composition, characterized in that it comprises the following steps: S1: Add all components except glass fiber into a high-speed mixer according to the proportion and mix for 2-5 minutes to obtain a premix; S2: The premix is ​​added into the twin-screw extruder from the main feed port, and the glass fiber is added into the twin-screw extruder from the side feed port according to the ratio; S3: Melting at 220-270° C., the temperatures of the barrels of the twin-screw extruder from the feed port to the die are: 220-240° C., 230-250° C., 230-250° C., 230-250° C., 240-260° C., 240-260° C., 250-270° C., 250-270° C., 250-270° C., the screw speed is 250-400 rpm, the feed rate is 50-200 kg / h, the vacuum degree is (-0.1)-0 MPa, and the PET resin composition is obtained by cooling and granulating.

[0022] The present invention also provides application of the PET resin composition for preparing products requiring ultrasonic welding.

[0023] The present invention has the following beneficial effects: The present invention can reduce the crystallization of the material by optimizing the content of isophthalic acid (IPA) in PET, which is beneficial to ultrasonic welding and improves the ultrasonic welding strength. PETG resin with a specific viscosity is introduced into the system as an ultrasonic welding agent to reduce the crystallization performance of the PET material, so that the energy demand during welding is low and the energy transfer efficiency is high, thereby achieving the purpose of improving the ultrasonic welding strength.

[0024] By optimizing the viscosity of PET and PETG, the ultrasonic welding strength is effectively improved. The reason may be that the viscosity of PET and PETG is similar, and the excessive difference in viscosity will not cause uneven distribution of PET and PETG in the material, thereby reducing the ultrasonic welding strength.

[0025] By optimizing the toughening agent content, high ultrasonic welding strength can be obtained while ensuring the toughness of the material. 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 it will strongly absorb the transmitted vibration energy of the ultrasonic wave, thereby reducing the welding strength.

[0026] By using a nucleating agent of a compound system, the material can obtain a higher ultrasonic welding strength. If montanic acid sodium salt is used alone, the amount required to be added is relatively large. At the same time, since montanic acid sodium salt belongs to a sodium salt system, it will degrade the PET resin, causing the viscosity of the system to decrease. In addition, there is no talcum powder as an inorganic nucleation site, and the bulk strength of the material is low, thereby reducing the ultrasonic welding effect. If talcum powder is used alone, there are only inorganic nucleation sites at this time, but since the molecular chain of PET is difficult to move, the bulk strength of the material will also decrease, thereby affecting the ultrasonic welding strength. DETAILED DESCRIPTION

[0027] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0028] The raw materials used in the present invention come from: PET resin 1: PET BG80, intrinsic viscosity 0.80 dL / g, IPA content 1.3-1.5%, Sinopec Yizheng Chemical Fiber Co., Ltd.

[0029] PET resin 2: PET CR-8828, intrinsic viscosity 0.87 dL / g, IPA content 1.5~2.0%, China Resources Chemical Technology Co., Ltd.

[0030] PET resin 3: PET CR-8863, intrinsic viscosity 0.80 dL / g, IPA content 1.6-2.0%, China Resources Chemical Technology Co., Ltd.

[0031] PET resin 4: PET CR-8839, intrinsic viscosity 0.80 dL / g, IPA content 0.2-0.5%, China Resources Chemical Technology Co., Ltd.

[0032] PET resin 5: PET CR-7702, intrinsic viscosity 0.5 dL / g, IPA content 1.3-1.5%, China Resources Chemical Technology Co., Ltd.

[0033] PET resin 6: PET CR-8818, intrinsic viscosity 0.81 dL / g, IPA content 3~4%, China Resources Chemical Technology Co., Ltd.

[0034] PET resin 7: PET FG600, intrinsic viscosity 0.68 dL / g, IPA content 0%, Sinopec Yizheng Chemical Fiber Co., Ltd.

[0035] PETG resin 1: AKOLYT™ KM 900, intrinsic viscosity 0.74-0.78 dL / g, Selenis Portugal, SA.

[0036] PETG resin 2: Eastar 6763, intrinsic viscosity 0.7-0.74 dL / g, Eastman.

[0037] PETG resin 3: PETG CR-5511, intrinsic viscosity 0.79-0.81 dL / g, China Resources Chemical Technology Co., Ltd.

[0038] PETG resin 4: FLOW™ 65, intrinsic viscosity 0.63-0.67 dL / g, Selenis Portugal, SA.

[0039] PETG resin 5: GEO™ LF 451, intrinsic viscosity 1.1-1.2 dL / g, Selenis Portugal, SA.

[0040] Toughener 1: Elvaloy resins PTW, ethylene-butyl acrylate-glycidyl methacrylate, DuPont.

[0041] Toughener 2: Lotader AX8900, ethylene-methyl acrylate-glycidyl methacrylate, Arkema.

[0042] Toughener 3: ELVALOY AC RESIN 1125, ethylene methyl acrylate copolymer, DuPont.

[0043] Glass fiber: ECS11-4.5-534A, alkali-free glass fiber, diameter 11um, length 4.5mm, China Jushi Co., Ltd.

[0044] Lignanic acid sodium salt: LICOMONT NAV101 PWD, Guangzhou Fengtian Chemical Co., Ltd.

[0045] Sodium stearate: Gaomi Xinwei Additive Co., Ltd.

[0046] Talc: HTPULTRA5L, Liaoning Aihaiyimi Mining Co., Ltd.

[0047] Lubricant 1: PETS-AP Pentaerythritol Tetrastearate, Faki Asia Pacific Pte Ltd.

[0048] Lubricant 2: Licowax PED 521, oxidized polyethylene wax, Clariant.

[0049] Various test methods: Ultrasonic welding strength: The material is injected into welding strips at 270°C, and the upper and lower strips are placed in the positioning blocks of the ultrasonic welding machine. The welding pressure is set to 2kg / cm 2 , welding time 0.4s, hardening time 0.4s, ultrasonic welding. After welding, the tensile strength was tested at a tensile rate of 10mm / min using a universal tensile machine to characterize the ultrasonic welding strength.

[0050] Table 1 Examples 1-7 PET resin composition components by weight and test results:

[0051] It can be seen from Examples 5-7 that the nucleating agent is compounded by sodium montanate and talc in a weight ratio of (2-4): (6-8). When the weight ratio of sodium montanate and talc is preferably (2.5-3.5): (6.5-7.5), the PET resin composition has better ultrasonic welding strength.

[0052] Table 2 Weight parts of each component of PET resin composition of Examples 8-10 and test results

[0053] It can be seen from Examples 6 and 8 that the preferred isophthalic acid content by weight is 1.3-1.5%, and adding isophthalic acid to PET within this content range can achieve better ultrasonic welding strength.

[0054] It can be seen from Examples 6 / 9-10 that the smaller the absolute value of the difference in intrinsic viscosity between the PET resin and the PETG resin, the higher the ultrasonic welding strength of the PET resin composition.

[0055] Table 2 Comparative Examples 1-6 PET resin composition components by weight and test results:

[0056] From Comparative Examples 1-3, it can be seen that the absolute value of the difference in intrinsic viscosity 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 reason may be that the viscosity of PET and PETG differs greatly, resulting in uneven distribution of PET and PETG in the material, thereby reducing the ultrasonic welding strength.

[0057] It can be seen from Comparative Examples 4-6 that the content of isophthalic acid exceeds the range of 1-2%. Too low or too high isophthalic acid will lead to a decrease in ultrasonic welding strength.

[0058] Table 3 Comparative Examples 7-11 PET resin composition components by weight and test results:

[0059] It can be seen from Comparative Examples 7-8 that the weight portion of the toughening agent exceeding 2-5 parts will have a certain impact on the ultrasonic welding strength. Comparative Example 7 is compared with Example 6. In the case of no toughening agent added, the ultrasonic welding strength of the PET resin composition decreases to a certain extent. Comparative Example 8 adds 7 parts of toughening agent by weight, which exceeds the limited range, resulting in a decrease in the ultrasonic welding strength of the PET resin composition.

[0060] It can be seen from Comparative Example 9 that adding excessive PETG resin will also cause the ultrasonic welding strength of the PET resin composition to decrease significantly.

[0061] It can be seen from Comparative Example 10 that the choice of toughening agent has an impact on the ultrasonic welding strength.

[0062] It can be seen from Comparative Example 11 that the use of sodium stearate instead of sodium montanate as a nucleating agent combined with talcum powder has an impact on the ultrasonic welding strength.

Claims

1. A PET resin composition, characterized in that By weight, it contains the following components: PET resin 60-75 parts; PETG resin 5-15 parts; 2-5 parts of toughening agent; Glass fiber 18-25 parts; Nucleating agent 0.2-0.8 parts; The PET resin contains isophthalic acid, and the weight percentage content of the isophthalic acid in the PET resin is: 1-2%; The nucleating agent is prepared by mixing sodium montanate and talc in a weight ratio of (2-4): (6-8); The absolute value of the difference in intrinsic viscosity between PET resin and PETG resin is less than 0.13 dL / g.

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

4. A 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 toughening agent is selected from any one or more of ethylene-butyl acrylate-glycidyl methacrylate terpolymer and ethylene-methyl acrylate-glycidyl methacrylate terpolymer.

6. A PET resin composition according to claim 1, characterized in that, The glass fiber is an alkali-free glass fiber, and the diameter of the alkali-free glass fiber is 10-13um and the length is 3.0-4.5mm.

7. A PET resin composition according to claim 1, characterized in that: The nucleating agent is prepared by mixing sodium montanate and talcum powder in a weight ratio of (2.5-3.5): (6.5-7.5).

8. A PET resin composition according to claim 1, characterized in that: The invention also comprises the following components by weight: 0.2-0.8 parts of lubricant, wherein the lubricant is selected from any one or more of pentaerythritol ester or oxidized polyethylene wax.

9. The method for preparing the PET resin composition according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Add all components except glass fiber into a high-speed mixer according to the proportion and mix for 2-5 minutes to obtain a premix; S2: The premix is ​​added into the twin-screw extruder from the main feed port, and the glass fiber is added into the twin-screw extruder from the side feed port according to the ratio; S3: Melting at 220-270° C., the temperatures of the barrels of the twin-screw extruder from the feed port to the die are: 220-240° C., 230-250° C., 230-250° C., 230-250° C., 240-260° C., 240-260° C., 250-270° C., 250-270° C., 250-270° C., the screw speed is 250-400 rpm, the feed rate is 50-200 kg / h, the vacuum degree is (-0.1)-0 MPa, and the PET resin composition is obtained by cooling and granulating.

10. The use of the PET resin composition according to any one of claims 1 to 8, characterized in that: Used to prepare products that require ultrasonic welding.

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