Lubricating material for processing oxidation-resistant PET (polyethylene terephthalate) products and preparation method of lubricating material

Abstract

The invention discloses a lubricating material for processing an oxidation-resistant PET (Polyethylene Terephthalate) product and a preparation method of the lubricating material, and relates to the technical field of preparation of PET lubricating materials. The lubricating material consists of 60-85 parts of a main lubricant, 5-20 parts of an auxiliary lubricant, 0.5-3 parts of an antioxidant and 2-10 parts of a dispersing agent. During preparation, powder with D50 smaller than or equal to 30 microns is prepared through a staged mixing process, a twin-screw extrusion melt blending process and a 10-20 DEG C / min rapid cooling process. 0.1%-1.5% of the material is added during PET processing, the light transmittance of a product reaches 90.8% or above, the haze is smaller than or equal to 1.4%, the oxidation induction period is prolonged to 30 minutes or above, meanwhile, the friction coefficient is reduced to 0.27 or below, and the material has excellent mechanical strength by utilizing the high bond energy characteristic of a C-D bond of the deuterated antioxidant and cooperating with a nano dispersion system. Through molecular structure design and process innovation, the technical problem that the light transmittance, oxidation resistance and processing lubricity of a traditional PET material are difficult to synergistically improve is solved.

Description

Technical Field

[0001] The invention relates to the technical field of preparing PET lubricating materials, and in particular to a lubricating material for processing oxidation-resistant PET products and a preparation method thereof. Background Art

[0002] Polyethylene terephthalate (PET) is a commonly used thermoplastic polyester material, which has been widely used in packaging, fiber, film, etc. due to its good mechanical properties, chemical stability and molding processing performance. However, there are some problems in the processing and use of PET, which limits its further application.

[0003] In terms of anti-oxidation, the ester groups in the PET molecular chain are prone to oxidation reactions under conditions such as high temperature, oxygen, and light, resulting in a decrease in material performance, such as reduced mechanical properties and poor color. Anti-oxidation properties are particularly important in PET products that need to be used for a long time or in harsh environments. Although traditional antioxidants can inhibit the oxidation of PET to a certain extent, they have problems such as large addition amounts, poor compatibility, and affecting material transparency.

[0004] In terms of high transparency, the transparency of PET products is crucial for their application in packaging, optics and other fields. However, PET itself has a high degree of crystallinity, and it is easy to produce turbidity during processing due to the addition of additives or the influence of processing conditions, resulting in reduced light transmittance. Some methods currently on the market to improve the transparency of PET often require complex processes or the addition of a large amount of additives, which not only increases production costs, but may also have an adverse effect on other properties of the material.

[0005] In addition, good lubrication is also required during PET processing to reduce the friction coefficient, improve processing efficiency and product surface quality. However, existing lubricating materials often cannot meet the requirements of high permeability and oxidation resistance at the same time, and have problems such as single performance and poor overall effect, making it difficult to meet the market demand for high-performance PET products. Summary of the invention

[0006] The purpose of the present invention is to provide a PET product processing modified lubricating material with high transparency, oxidation resistance and good lubrication performance in view of the problems existing in the prior art.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a lubricating material for processing oxidation-resistant PET products, comprising the following components by weight: 60-85 parts of a main lubricant, 5-20 parts of an auxiliary lubricant, 0.5-3 parts of an antioxidant, and 2-10 parts of a dispersant; The structure of the antioxidant is shown in Formula 1: Formula 1; Z1 is selected from any one of O, S, C(CH3)(CH3); D represents deuterium.

[0008] Furthermore, the antioxidant is any one of the compounds represented by the following structures: ; ; .

[0009] Furthermore, the main lubricant is a composite of a fatty acid amide compound and a polysiloxane, where the mass ratio of the fatty acid amide compound to the polysiloxane is 7 parts : (3 - 5) parts.

[0010] Furthermore, the auxiliary lubricant is oxidized polyethylene wax.

[0011] Furthermore, the dispersant is polyvinylpyrrolidone.

[0012] Furthermore, the fatty acid amide compound is selected from any one of stearamide, erucamide, and oleamide.

[0013] Furthermore, the polysiloxane is selected from any one of dimethylpolysiloxane and amino - modified polysiloxane.

[0014] A preparation method of a lubricating material for processing oxidation - resistant PET products, comprising the following steps: S1. Mix the main lubricant and the auxiliary lubricant in proportion, and stir at 300 - 500 rpm at 50 - 70 °C for 20 - 40 minutes; S2. Add the antioxidant and the dispersant, and raise the temperature to 120 - 140 °C for melt blending for 1 - 2 hours; S3. Cool to room temperature, and obtain a powder with a particle size D50 ≤ 30 μm after pulverization and sieving.

[0015] Furthermore, the cooling rate in S3 is 10 - 20 °C / min.

[0016] Furthermore, in S2, a twin - screw extruder is used for the melt blending, the screw speed is 200 - 400 rpm, and the melt residence time is 2 - 5 minutes.

[0017] The high shear of the twin - screw extruder enables the antioxidant to be uniformly dispersed in nanoparticles, reducing the light scattering rate. The rapid cooling at 10 - 20 °C / min inhibits the growth of PET spherulites.

[0018] A highly transparent PET product, in the processing of which the above-mentioned processing and modifying lubricating material for highly transparent oxidation-resistant PET products is added, and the addition amount is 0.1%-1.5% of the mass of the PET matrix.

[0019] In the antioxidant of the present invention, the bond energy of the C-D bond is higher than that of the C-H bond, significantly enhancing the ability of the molecule to resist free radical attack. Under the high-temperature conditions of PET processing, the deuterated structure can delay the self-degradation of the antioxidant and extend the free radical capture cycle. When the Z1 site is O / S, an additional free radical quenching path is provided through lone pair electrons; if it is C(CH3)(CH3), the active group is protected through steric hindrance effect, improving the antioxidant persistence. When stearamide and dimethyl polysiloxane are compounded at a mass ratio of 7:4, a continuous lubricating film can be formed on the surface of PET, reducing the processing friction heat and indirectly reducing the thermal oxidation risk. The carboxyl functional group of the oxidized polyethylene wax auxiliary lubricant forms a hydrogen bond with the amino group of the antioxidant, promoting the directional distribution of the antioxidant in the PET / lubricant interface region. The PVP dispersant is adsorbed on the surface of the antioxidant through π-π stacking to prevent its aggregation and ensure the light transmittance.

[0020] A lubricating material for processing oxidation-resistant PET products according to the present invention constructs an efficient antioxidant network at the molecular level through the structural innovation of deuterated antioxidants and the synergistic dispersion of multiple components, and simultaneously optimizes the optical properties through nano-dispersion and crystallization control.

[0021] Compared with the prior art, the beneficial effects of the present invention are: 1. Significantly improve the antioxidant performance: Through the structural innovation of deuterated antioxidants and molecular synergistic effects, the oxidative degradation during processing and use is effectively inhibited, and the service life of the material is extended.

[0022] 2. Optimize the optical transparency: The synergistic effect of nano-scale dispersion and crystallization control technology reduces the light scattering effect, significantly improving the light transmittance of the product and reducing the haze.

[0023] 3. Synergistically enhance the lubrication and mechanical properties: The composite lubrication system reduces the processing friction while maintaining the mechanical strength of the material, achieving a balanced improvement in processing efficiency and product quality. Description of the Drawings

[0024] Figure 1 is the 1 HNMR spectrum of the antioxidant synthesized in Preparation Example 1 of the present invention. Detailed Embodiments

[0025] The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0026] Preparation Example 1: ; Step 1: Under nitrogen protection, 20.00 g of Raw Material 1 and 20.99 g of AlCl3 were added to 200 g of dichloromethane, and then a solution of 13.84 g of Raw Material 2 dissolved in 75 ml of dichloromethane was slowly added dropwise. The feeding was carried out at -20 to 10 °C, and the reaction was carried out at room temperature for 6 h. After the reaction was complete, the pH of the system was adjusted to neutral with 0.1 mol / L HCl at 0 °C, 100 g of water was added, stirred for 30 min, allowed to stand for liquid separation, and the organic phase was retained. The aqueous phase was washed with 50 ml of dichloromethane 2 - 3 times, the organic phases were combined, dried with 20 g of anhydrous magnesium sulfate, filtered, and concentrated by rotary evaporation. Silica gel column chromatography purification was carried out using petroleum ether and ethyl acetate as eluents to obtain 21.82 g of Intermediate 1. MS[MS+1]: 362.

[0027] Step 2: Under nitrogen protection, 21.82 g of Intermediate 1, 22.12 g of acetic acid, and 100 g of toluene were added to the reaction flask, and then 8.17 g of hydrogen peroxide was slowly added. After the reaction temperature was raised to 35 °C, it was stirred for 1 h, and the solvent was concentrated by rotary evaporation. Then 100 g of n-heptane was added, stirred for 1 - 3 h, filtered, and concentrated by rotary evaporation. Finally, silica gel column chromatography purification was carried out using petroleum ether and ethyl acetate as eluents to obtain 18.40 g of Intermediate 2. MS[MS+1]: 394.

[0028] Step 3: Under nitrogen protection, 18.40 g of Intermediate 2 and 200 ml of ultra-dry THF were added to the reaction flask, and the temperature was lowered to -70 °C. Then 3.16 g of n-butyllithium was added dropwise, and after the addition was complete, it was stirred for 1 h. Then 13.13 g of triisopropyl borate was added dropwise, and after the addition was complete, it was allowed to rise to room temperature naturally, and the reaction was carried out overnight. After concentration by rotary evaporation, silica gel column chromatography purification was carried out using petroleum ether and ethyl acetate as eluents to obtain 12.75 g of Intermediate 3. MS[MS+1]: 361.

[0029] Step 4: Under nitrogen protection, add 12.75 g of intermediate 3, 25.29 g of raw material 3, 9.78 g of anhydrous potassium carbonate, and 1.23 g of tetrakis(triphenylphosphine)palladium to the reaction flask, dissolve them in a mixed solution composed of 200 g of toluene, ethanol, and water (volume ratio 2:1:1), heat to 75 °C and reflux for 10 hours. Turn off the heating, cool to room temperature, and let it stand for liquid separation. The aqueous phase is extracted twice with ethyl acetate, the organic phases are combined, washed three times with water, and then dried by rotary evaporation. Finally, silica gel column chromatography purification is carried out using petroleum ether and ethyl acetate as eluents to obtain 22.43 g of the antioxidant. The 1 1H NMR spectrum is shown in Figure 1 . MS [MS + 1]: 846.

[0030] 1 1H NMR (CDCl₃) δ 8.90 (d, 1H), 8.18 (s, 1H), 7.91 (d, 1H), 7.84 - 7.73 (m, 2H), 7.66 (s, 1H), 7.61 (d, 1H), 7.52 (t, 3H), 7.43 (d, 1H), 7.36 - 7.34 (d, 1H), 7.18 (d, 1H), 7.00 - 6.91 (m, 2H), 6.67 (d, 1H), 6.64 - 6.56 (m, 2H), 6.55 - 6.44 (m, 2H), 5.09 (d, 2H), 4.50 - 4.42 (m, 1H), 4.05 - 3.89 (m, 3H), 3.16 - 2.97 (m, 2H), 3.01 (s, 1H), 2.93 - 2.76 (m, 2H).

[0031] Preparation Example 2: ; Refer to the synthesis method of Preparation Example 1, and replace the with: , and the rest is the same as in Example 1. MS [MS + 1]: 862.

[0032] Preparation Example 3: ; Refer to the synthesis method of Preparation Example 1, and replace the with: , and the rest is the same as in Example 1. MS [MS + 1]: 872.

[0033] Example 1: Preparation of a lubricating material for processing oxidation-resistant PET products: S1. Mix the main lubricant (the mass ratio of stearamide to dimethylpolysiloxane is 7 parts: 5 parts) and the auxiliary lubricant (polyethylene wax oxide, 20 parts) in a ratio of 7:3, and stir at 500 rpm for 40 minutes at 70 °C; S2. Add the antioxidant (prepared in Preparation Example 1, 3 parts) and the dispersant (polyvinylpyrrolidone, 10 parts), and raise the temperature to 140 °C for melt blending (using a twin-screw extruder, the screw speed is 400 rpm, and the melt residence time is 5 minutes) for 2 hours; S3. Cool to room temperature (the cooling rate is 10 °C / min), and obtain a powder with a particle size D50 ≤ 30 μm after pulverization and sieving.

[0034] Example 2: Preparation of a lubricating material for processing oxidation-resistant PET products: S1. Mix the main lubricant (the mass ratio of stearamide to dimethylpolysiloxane is 7 parts: 5 parts, 85 parts) and the auxiliary lubricant (polyethylene wax oxide, 20 parts) in a ratio of 7:3, and stir at 500 rpm for 40 minutes at 70 °C; S2. Add the antioxidant (prepared in Preparation Example 2, 3 parts) and the dispersant (polyvinylpyrrolidone, 10 parts), and raise the temperature to 140 °C for melt blending (using a twin-screw extruder, the screw speed is 400 rpm, and the melt residence time is 5 minutes) for 2 hours; S3. Cool to room temperature (the cooling rate is 10 °C / min), and obtain a powder with a particle size D50 ≤ 30 μm after pulverization and sieving.

[0035] Example 3: Preparation of a lubricating material for processing oxidation-resistant PET products: S1. Mix the main lubricant (the mass ratio of stearamide to dimethylpolysiloxane is 7 parts: 5 parts) and the auxiliary lubricant (polyethylene wax oxide, 20 parts) in a ratio of 7:3, and stir at 500 rpm for 40 minutes at 70 °C; S2. Add the antioxidant (prepared in Preparation Example 3, 3 parts) and the dispersant (polyvinylpyrrolidone, 10 parts), and raise the temperature to 140 °C for melt blending (using a twin-screw extruder, the screw speed is 400 rpm, and the melt residence time is 5 minutes) for 2 hours; S3. Cool to room temperature (the cooling rate is 10 °C / min), and obtain a powder with a particle size D50 ≤ 30 μm after pulverization and sieving.

[0036] Comparative Example 1: Preparation of a lubricating material for processing oxidation-resistant PET products: S1. Mix the main lubricant (the mass ratio of stearamide to dimethylpolysiloxane is 7 parts: 5 parts) and the auxiliary lubricant (polyethylene wax oxide, 20 parts) in a ratio of 7:3, and stir at 500 rpm for 40 minutes at 70 °C; S2. Add the antioxidant (comparative compound 1, 3 parts) and the dispersant (polyvinylpyrrolidone, 10 parts), and raise the temperature to 140 °C for melt blending (using a twin-screw extruder, the screw speed is 400 rpm, and the melt residence time is 5 minutes) for 2 hours; S3. Cool to room temperature (the cooling rate is 10 °C / min), and obtain a powder with a particle size D50 ≤ 30 μm after crushing and sieving.

[0037] Comparative compound 1: 。

[0038] Comparative example 2: Preparation of a lubricating material for processing oxidation-resistant PET products: S1. Mix the main lubricant (the mass ratio of stearamide to dimethylpolysiloxane is 7 parts: 5 parts) and the auxiliary lubricant (polyethylene wax oxide, 20 parts) in a ratio of 7:3, and stir at 500 rpm for 40 minutes at 70 °C; S2. Add the dispersant (polyvinylpyrrolidone, 10 parts), and raise the temperature to 140 °C for melt blending (using a twin-screw extruder, the screw speed is 400 rpm, and the melt residence time is 5 minutes) for 2 hours; S3. Cool to room temperature (the cooling rate is 10 °C / min), and obtain a powder with a particle size D50 ≤ 30 μm after crushing and sieving.

[0039] Application example 1: 1. Material composition: PET matrix: polyethylene terephthalate; modified lubricating material: Example 1, with an addition amount of 1% of the PET matrix.

[0040] 2. Processing process: Pre-dry the modified lubricating material prepared in Example 1 and PET chips at 50 °C for 4 hours (moisture ≤ 50 ppm), and use a twin-screw extruder (L / D = 40:1) (temperature zone: feeding section 220 °C → plasticizing section 260 °C → homogenizing section 275 °C → die head 270 °C, screw speed: 350 rpm, melt pressure: 12 MPa), extrude through a T-shaped die head (die lip gap 0.8 mm) to a 25 °C cooling roll to form a cast film with a thickness of 200 μm, and perform biaxial stretching (longitudinal stretching: preheating temperature 95 °C, stretching temperature 110 °C, stretching ratio 3.5:1; transverse stretching: preheating temperature 100 °C, stretching temperature 125 °C, stretching ratio 4.0:1), heat setting, relaxation heat treatment at 230 °C for 10 seconds, and a cooling rate of 15 °C / s to obtain a high-transparency oxidation-resistant PET film.

[0041] Application Examples 2 - 3: Referring to the preparation method of Application Example 1, the modified lubricating materials therein were sequentially replaced with those of Examples 2 - 3. The rest was the same as that of Application Example 1.

[0042] Comparative Application Examples 1 - 2: Referring to the preparation method of Application Example 1, the modified lubricating materials therein were sequentially replaced with those of Comparative Examples 1 - 2. The rest was the same as that of Application Example 1.

[0043] Table 1. Performance Parameter Test Table Compared with the comparative application examples, each application example shows a positive improvement trend in terms of light transmittance, oxidation induction period, and tensile strength. At the same time, the haze and friction coefficient show a downward trend, indicating that the lubricating material of the present invention effectively enhances the antioxidant performance and lubrication effect while maintaining the high transparency of PET products, and does not damage the mechanical strength of the material. With the optimization of the deuterated structure of the antioxidant (from Application Example 1 to Application Example 3), each performance index shows a gradient improvement, while the systems with traditional antioxidants (Comparative Application Example 1) or without antioxidants (Comparative Application Example 2) show a significant decline in comprehensive performance.

[0044] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A lubricating material for processing oxidation-resistant PET products, characterized in that, It comprises the following components by mass parts: 60 - 85 parts of a main lubricant, 5 - 20 parts of an auxiliary lubricant, 0.5 - 3 parts of an antioxidant, and 2 - 10 parts of a dispersant; The structure of the antioxidant is the structure shown in Formula 1: Formula 1; Z1 is selected from any one of O, S, C(CH3)(CH3); D represents deuterium.

2. The lubricating material for processing oxidation-resistant PET products according to claim 1, characterized in that The antioxidant is any one of the compounds shown in the following structures: ； ； 。 3. A lubricating material for processing oxidation-resistant PET products according to claim 1, characterized in that, The main lubricant is a composite of a fatty acid amide compound and a polysiloxane, and the mass ratio of the fatty acid amide compound to the polysiloxane is 7 parts : (3 - 5) parts.

4. A lubricating material for processing oxidation-resistant PET products according to claim 1, characterized in that, The auxiliary lubricant is oxidized polyethylene wax.

5. A lubricating material for processing oxidation-resistant PET products according to claim 1, characterized in that, The dispersant is polyvinylpyrrolidone.

6. A lubricating material for processing oxidation-resistant PET products according to claim 3, characterized in that, The fatty acid amide compound is selected from any one of stearamide, erucamide, and oleamide; The polysiloxane is selected from any one of dimethylpolysiloxane and amino - modified polysiloxane.

7. A preparation method of a lubricating material for processing an oxidation-resistant PET product according to any one of claims 1-6, characterized in that, It includes the following steps: S1. Mix the main lubricant and the auxiliary lubricant in proportion, and stir at 300 - 500 rpm for 20 - 40 minutes at 50 - 70 °C; S2. Add the antioxidant and the dispersant, and raise the temperature to 120 - 140 °C for melt - blending for 1 - 2 hours; S3. Cool to room temperature, and obtain a powder with a particle size D50 ≤ 30 μm after pulverization and sieving.

8. The preparation method of a lubricating material for processing oxidation-resistant PET products according to claim 7, characterized in that, The cooling rate in S3 is 10 - 20 °C / min.

9. The preparation method of a lubricating material for processing oxidation-resistant PET products according to claim 7, characterized in that, In S2, a twin - screw extruder is used for the melt - blending, the screw speed is 200 - 400 rpm, and the melt residence time is 2 - 5 minutes.

10. A highly transparent PET product, characterized in that, During its processing, the oxidation - resistant lubricating material for PET product processing described in any one of claims 1 - 6 is added, and the addition amount is 0.1% - 1.5% of the mass of the PET matrix.

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