A lubricating material for processing oxidation-resistant PET products and its preparation method

Abstract

The present invention discloses a lubricating material for processing oxidation-resistant PET products and a preparation method thereof, and relates to the technical field of preparing 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 dispersant. During preparation, a powder with D50 ≤ 30 μm is obtained by staged mixing, twin-screw extrusion melt blending, and a 10-20°C / min rapid cooling process. The material is added at 0.1%-1.5% in PET processing, and the high bond energy characteristics of the C-D bond of the deuterated antioxidant are used in conjunction with a nano-dispersion system to achieve a product transmittance of more than 90.8%, a haze of ≤ 1.4%, an oxidation induction period of more than 30 minutes, and a friction coefficient of less than 0.27, with excellent mechanical strength. The present invention solves the technical problem that the transmittance, oxidation resistance, and processing lubricity of traditional PET materials are difficult to improve in a coordinated manner through molecular structure design and process innovation.

Description

Technical Field

[0001] The present 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. Due to its good mechanical properties, chemical stability, and molding processability, it is widely used in packaging, fibers, films, and other fields. However, PET has some problems during processing and use, which limit its further application.

[0003] Regarding oxidation resistance, the ester groups in PET molecular chains are susceptible to oxidation reactions under conditions such as high temperature, oxygen, and light, leading to a decline in material performance, such as reduced mechanical properties and poor color. Antioxidant properties are particularly important in PET products that require long-term use or are used in harsh environments. While traditional antioxidants can inhibit PET oxidation to a certain extent, they have issues such as high dosage, poor compatibility, and reduced transparency.

[0004] The transparency of PET products is crucial for their applications in packaging, optics, and other fields. However, PET itself has a high degree of crystallinity and is easily clouded during processing due to the addition of additives or the influence of processing conditions, resulting in reduced light transmittance. Currently available methods for improving PET transparency often require complex processes or the addition of large amounts of additives, which not only increases production costs but may also adversely affect other properties of the material.

[0005] PET processing also requires good lubrication to reduce friction, improve processing efficiency, and enhance product surface quality. However, existing lubricants often struggle to simultaneously meet the requirements for high transparency and oxidation resistance. They suffer from single-function properties and poor overall effectiveness, making it difficult to meet 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 response to 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;

[0008] The structure of the antioxidant is shown in Formula 1:

[0009] Formula 1;

[0010] The Z1 is selected from any one of O, S, and C(CH3)(CH3);

[0011] The D represents deuterium.

[0012] Furthermore, the antioxidant is any one of the compounds shown in the following structures:

[0013] ;

[0014] ;

[0015] .

[0016] Furthermore, the main lubricant is a complex of a fatty acid amide compound and polysiloxane, wherein the mass ratio of the fatty acid amide compound to the polysiloxane is 7 parts:(3-5) parts.

[0017] Furthermore, the auxiliary lubricant is oxidized polyethylene wax.

[0018] Furthermore, the dispersant is polyvinyl pyrrolidone.

[0019] Furthermore, the fatty acid amide compound is selected from any one of stearamide, erucamide, and oleamide.

[0020] Furthermore, the polysiloxane is selected from any one of dimethyl polysiloxane and amino-modified polysiloxane.

[0021] A method for preparing a lubricating material for processing oxidation-resistant PET products comprises the following steps:

[0022] S1. The main lubricant and the auxiliary lubricant are mixed in proportion and stirred at 300-500 rpm at 50-70 ° C for 20-40 minutes;

[0023] S2. Add the antioxidant and dispersant, heat to 120-140 ° C and melt blend for 1-2 hours;

[0024] S3. Cool to room temperature, crush and sieve to obtain a powder with a particle size of D50 ≤ 30 μm.

[0025] Furthermore, the cooling rate in S3 is 10-20°C / min.

[0026] Furthermore, the melt blending in S2 is performed using a twin-screw extruder with a screw speed of 200-400 rpm and a melt residence time of 2-5 minutes.

[0027] The high shear of the twin-screw extruder evenly disperses the antioxidant in nanoparticles, reducing light scattering. Rapid cooling at 10-20°C / min inhibits the growth of PET spherulites.

[0028] A high-transmittance PET product is added during the processing of the above-mentioned high-transmittance and oxidation-resistant PET product processing modified lubricating material, with the added amount being 0.1%-1.5% of the mass of the PET matrix.

[0029] The CD bond energy in the antioxidant described in the present invention is higher than that of the CH bond, which significantly enhances the molecule's ability to resist free radical attack. Under high-temperature conditions of PET processing, the deuterated structure can delay the degradation of the antioxidant itself and prolong the free radical capture cycle. When the Z1 site is O / S, an additional free radical quenching path is provided by the lone pair of electrons; if it is C(CH3)(CH3), the active group is protected by the steric effect, thereby improving the antioxidant durability. When stearamide and dimethyl polysiloxane are compounded in a mass ratio of 7:4, a continuous lubricating film can be formed on the PET surface, reducing processing friction heat and indirectly reducing the risk of thermal oxidation. 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 area. The PVP dispersant is adsorbed on the surface of the antioxidant through π-π stacking to prevent its agglomeration and ensure light transmittance.

[0030] The lubricating material for processing oxidation-resistant PET products described in the present invention constructs a high-efficiency antioxidant network at the molecular level through structural innovation and multi-component synergistic dispersion of deuterated antioxidants, and achieves optical performance optimization through nano-dispersion and crystallization control.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. Significantly improve antioxidant performance: Through the structural innovation and molecular synergy of deuterated antioxidants, oxidative degradation during processing and use is effectively inhibited, extending the service life of the material.

[0033] 2. Optimize optical transparency: Nano-scale dispersion and crystallization control technology work together to reduce the light scattering effect, significantly improving the light transmittance of the product and reducing the haze.

[0034] 3. Synergistically enhance lubrication and mechanical properties: The composite lubrication system reduces processing friction while maintaining the mechanical strength of the material, achieving a balanced improvement in processing efficiency and product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The antioxidant synthesized in Preparation Example 1 of the present invention 1 HNMR spectrum. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] Preparation Example 1:

[0038] ;

[0039] Step 1: Under nitrogen, 20.00 g of raw material 1 and 20.99 g of AlCl₃ were added to 200 g of dichloromethane. A solution of 13.84 g of raw material 2 dissolved in 75 ml of dichloromethane was slowly added dropwise. The mixture was heated at -20 to 10°C and allowed to react at room temperature for 6 h. After completion of the reaction, 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, and allowed to stand for separation, retaining the organic phase. The aqueous phase was washed two to three times with 50 ml of dichloromethane. The combined organic phases were dried over 20 g of anhydrous magnesium sulfate, filtered, and spin-dried. Purification by silica gel column chromatography using petroleum ether and ethyl acetate as eluents afforded 21.82 g of intermediate 1. MS[MS+1]: 362.

[0040] Step 2: Under nitrogen, add 21.82 g of Intermediate 1, 22.12 g of acetic acid, and 100 g of toluene to a reaction flask, followed by the slow addition of 8.17 g of hydrogen peroxide. Warm the reaction to 35°C, stir for 1 hour, and spin-dry the solvent. Add 100 g of n-heptane, stir for 1-3 hours, filter, and spin-dry. Finally, purify by silica gel column chromatography using petroleum ether and ethyl acetate as eluents to obtain 18.40 g of Intermediate 2. MS [MS+1]: 394.

[0041] Step 3: Under nitrogen, add 18.40 g of Intermediate 2 and 200 ml of ultra-dry THF to a reaction flask and cool to -70°C. Then, add 3.16 g of n-butyl lithium dropwise and stir for 1 hour. Then, add 13.13 g of triisopropyl borate dropwise. After addition, warm to room temperature and react overnight. After drying, purify by silica gel column chromatography using petroleum ether and ethyl acetate as eluents to obtain 12.75 g of Intermediate 3. MS [MS+1]: 361.

[0042] Step 4: Under nitrogen protection, add 12.75g of intermediate 3, 25.29g of raw material 3, 9.78g of anhydrous potassium carbonate, and 1.23g of tetrakis(triphenylphosphine)palladium to the reaction flask, dissolve in a mixed solution consisting of 200g of toluene, ethanol, and water (volume ratio 2:1:1), and heat to 75°C for reflux reaction for 10 hours. Turn off the heating, cool to room temperature, and stand for separation. The aqueous phase is extracted twice with ethyl acetate, the organic phases are combined, washed three times with water, and spin-dried. Finally, 22.43g of antioxidant is obtained by silica gel column chromatography using petroleum ether and ethyl acetate as eluents. 1 HNMR diagram Figure 1 . MS[MS+1]:846.

[0043] 1 HNMR (deuterated chloroform) δ8.90 (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).

[0044] Preparation Example 2:

[0045] ;

[0046] With reference to the synthetic method of Preparation Example 1, Replace with: , and the rest remained the same as Example 1. MS [MS+1]: 862.

[0047] Preparation Example 3:

[0048] ;

[0049] With reference to the synthetic method of Preparation Example 1, Replace with: , and the rest remained the same as Example 1. MS [MS+1]: 872.

[0050] Example 1:

[0051] Preparation of a lubricating material for processing oxidation-resistant PET products:

[0052] S1. The main lubricant (stearamide and dimethyl polysiloxane mass ratio of 7 parts: 5 parts) and the auxiliary lubricant (oxidized polyethylene wax, 20 parts) were mixed in a ratio of 7:3 and stirred at 500 rpm at 70 ° C for 40 minutes;

[0053] S2. The antioxidant (prepared in Preparation Example 1, 3 parts) and a dispersant (polyvinyl pyrrolidone, 10 parts) were added, and the temperature was raised to 140 ° C and melt blended (using a twin-screw extruder, a screw speed of 400 rpm, a melt residence time of 5 minutes) for 2 hours;

[0054] S3. Cool to room temperature (cooling rate of 10°C / min), crush and sieve to obtain a powder with a particle size D50 ≤ 30 μm.

[0055] Example 2:

[0056] Preparation of a lubricating material for processing oxidation-resistant PET products:

[0057] S1. The main lubricant (stearamide and dimethyl polysiloxane, 85 parts by mass in a ratio of 7 parts:5 parts) and the auxiliary lubricant (oxidized polyethylene wax, 20 parts) were mixed in a ratio of 7:3 and stirred at 500 rpm at 70 ° C for 40 minutes;

[0058] S2. The antioxidant (prepared in Preparation Example 2, 3 parts) and a dispersant (polyvinyl pyrrolidone, 10 parts) were added, and the temperature was raised to 140 ° C and melt blended (using a twin-screw extruder, a screw speed of 400 rpm, a melt residence time of 5 minutes) for 2 hours;

[0059] S3. Cool to room temperature (cooling rate of 10°C / min), crush and sieve to obtain a powder with a particle size D50 ≤ 30 μm.

[0060] Example 3:

[0061] Preparation of a lubricating material for processing oxidation-resistant PET products:

[0062] S1. The main lubricant (stearamide and dimethyl polysiloxane mass ratio of 7 parts: 5 parts) and the auxiliary lubricant (oxidized polyethylene wax, 20 parts) were mixed in a ratio of 7:3 and stirred at 500 rpm at 70 ° C for 40 minutes;

[0063] S2. The antioxidant (prepared in Preparation Example 3, 3 parts) and a dispersant (polyvinyl pyrrolidone, 10 parts) were added, and the temperature was raised to 140 ° C and melt blended (using a twin-screw extruder, a screw speed of 400 rpm, a melt residence time of 5 minutes) for 2 hours;

[0064] S3. Cool to room temperature (cooling rate of 10°C / min), crush and sieve to obtain a powder with a particle size D50 ≤ 30 μm.

[0065] Comparative Example 1:

[0066] Preparation of a lubricating material for processing oxidation-resistant PET products:

[0067] S1. The main lubricant (stearamide and dimethyl polysiloxane mass ratio of 7 parts: 5 parts) and the auxiliary lubricant (oxidized polyethylene wax, 20 parts) were mixed in a ratio of 7:3 and stirred at 500 rpm at 70 ° C for 40 minutes;

[0068] S2. The antioxidant (comparative compound 1, 3 parts) and the dispersant (polyvinyl pyrrolidone, 10 parts) were added, and the temperature was raised to 140 ° C and melt blended (using a twin-screw extruder, a screw speed of 400 rpm, a melt residence time of 5 minutes) for 2 hours;

[0069] S3. Cool to room temperature (cooling rate of 10°C / min), crush and sieve to obtain a powder with a particle size D50 ≤ 30 μm.

[0070] Comparative compound 1: .

[0071] Comparative Example 2:

[0072] Preparation of a lubricating material for processing oxidation-resistant PET products:

[0073] S1. The main lubricant (stearamide and dimethyl polysiloxane mass ratio of 7 parts: 5 parts) and the auxiliary lubricant (oxidized polyethylene wax, 20 parts) were mixed in a ratio of 7:3 and stirred at 500 rpm at 70 ° C for 40 minutes;

[0074] S2 was added to the dispersant (polyvinyl pyrrolidone, 10 parts), the temperature was raised to 140 ℃ melt blending (using a twin-screw extruder, a screw speed of 400 rpm, a melt residence time of 5 minutes) for 2 hours;

[0075] S3. Cool to room temperature (cooling rate of 10°C / min), crush and sieve to obtain a powder with a particle size D50 ≤ 30 μm.

[0076] Application Example 1:

[0077] 1. Material composition: PET matrix: polyethylene terephthalate; modified lubricating material: Example 1, the addition amount is 1% of the PET matrix.

[0078] 2. Processing technology: The modified lubricating material and PET chips prepared in Example 1 were pre-dried at 50°C for 4 hours (moisture ≤ 50 ppm) using a twin-screw extruder (L / D = 40:1) (temperature partitioning: feeding section 220°C → plasticizing section 260°C → homogenizing section 275°C → die head 270°C, screw speed: 350 rpm, melt pressure: 12 MPa), extruded through a T-die (die lip gap 0.8 mm) onto a 25°C cooling roller to form a cast sheet with a thickness of 200 μm, and biaxially stretched (longitudinal stretching: preheating temperature 95°C, stretching temperature 110°C, stretch ratio 3.5:1; transverse stretching: preheating temperature 100°C, stretching temperature 125°C, stretch ratio 4.0:1), heat set, and relaxation heat treatment at 230°C for 10 seconds with a cooling rate of 15°C / s to obtain a high-transparency, oxidation-resistant PET film.

[0079] Application Example 2-Application Example 3:

[0080] Referring to the preparation method of Application Example 1, the modified lubricating materials were replaced with those of Example 2 to Example 3 in sequence. The rest of the steps were the same as those of Application Example 1.

[0081] Comparative Application Example 1-Comparative Application Example 2:

[0082] Referring to the preparation method of Application Example 1, the modified lubricating materials were replaced with Comparative Example 1 to Comparative Example 2 in sequence. The rest remained the same as Application Example 1.

[0083] Table 1. Performance parameter test table

[0084]

[0085] Compared to the comparative application examples, each application example showed positive improvements in transmittance, oxidation induction period, and tensile strength, while haze and coefficient of friction showed downward trends. This demonstrates that the lubricating material of the present invention effectively enhances antioxidant properties and lubrication while maintaining high transparency in PET products, without compromising the material's mechanical strength. With the optimization of the deuterated structure of the antioxidant (Application Examples 1 to 3), various performance indicators showed a gradual improvement, while the system with a traditional antioxidant (Comparative Application Example 1) or without an antioxidant (Comparative Application Example 2) showed a significant decline in overall performance.

[0086] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A lubricating material for processing oxidation-resistant PET products, characterized in that: The following components are included by weight: 60-85 parts of main lubricant, 5-20 parts of auxiliary lubricant, 0.5-3 parts of antioxidant, and 2-10 parts of dispersant; The structure of the antioxidant is any one of the compounds shown in the following structures: ； ； 。 2. The lubricating material for processing oxidation-resistant PET products according to claim 1, characterized in that: The main lubricant is a compound of a fatty acid amide compound and polysiloxane, wherein the mass ratio of the fatty acid amide compound to the polysiloxane is 7 parts:(3-5) parts.

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

4. The lubricating material for processing oxidation-resistant PET products according to claim 1, characterized in that: The dispersant is polyvinyl pyrrolidone.

5. The lubricating material for processing oxidation-resistant PET products according to claim 2, 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 dimethyl polysiloxane and amino-modified polysiloxane.

6. A method for preparing a lubricating material for processing oxidation-resistant PET products according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. The main lubricant and the auxiliary lubricant are mixed in proportion and stirred at 300-500 rpm at 50-70 ° C for 20-40 minutes; S2. Add the antioxidant and dispersant, raise the temperature to 120-140 ° C and melt blend for 1-2 hours; S3. Cool to room temperature, crush and sieve to obtain a powder with a particle size of D50 ≤ 30 μm.

7. The method for preparing a lubricating material for processing oxidation-resistant PET products according to claim 6, characterized in that: The cooling rate in S3 is 10-20°C / min.

8. The method for preparing a lubricating material for processing oxidation-resistant PET products according to claim 6, characterized in that: The melt blending in S2 is performed using a twin-screw extruder with a screw speed of 200-400 rpm and a melt residence time of 2-5 minutes.

9. A high-transmittance PET product, characterized in that: During the processing, the high-transmittance and oxidation-resistant PET product processing modified lubricating material according to any one of claims 1 to 5 is added, and the added amount is 0.1% to 1.5% of the mass of the PET matrix.

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