Aging-resistant color master batch for thin film and preparation method thereof

Abstract

The application relates to an anti-aging color master batch for a film and a preparation method thereof, and belongs to the technical field of polyester color master batches. The components of the color master batch are as follows: 25-32 wt% of pigments, 0.35-0.48 wt% of modified anti-aging agents, 1.2-1.6 wt% of dispersants, 0.1-0.12 wt% of heat stabilizers and 2.8-3.6 wt% of lubricants, and the rest is PET resin; the modified anti-aging agent is formed by substituting 3-bromopropanol with tetramethylpiperidylamine to form an intermediate, and then esterifying the active alcohol hydroxyl group introduced in the intermediate molecule with oxalyl chloride monoethyl ester to form a double-chain double-ester structure, which has high compatibility with a PET matrix, is easy to disperse, forms a chelation effect through a double-chain double-ester structure containing a tertiary amine, is chelated with a metal-based pigment during blending, in-situ removes interface free radicals efficiently, effectively slows down interface aging, and forms a long-acting anti-aging effect.

Description

Technical Field

[0001] This invention belongs to the field of polyester masterbatch technology, specifically relating to an aging-resistant masterbatch for film and its preparation method. Background Technology

[0002] Polyethylene terephthalate (PET) film is widely used in food packaging, electronic optical films, and outdoor materials due to its excellent mechanical properties, transparency, and chemical resistance. However, PET is prone to photo-oxidative aging and hydrolysis when exposed to ultraviolet light, humid and hot environments, or during high-temperature processing, leading to problems such as deterioration of mechanical properties, yellowing, and interfacial delamination. To improve aging resistance, existing technologies mostly use hindered amine light stabilizers, such as the commonly used light stabilizer 770 and light stabilizer HA-18, which delay photodegradation by capturing free radicals. However, these methods have the following drawbacks:

[0003] Traditional hindered amine light stabilizers have insufficient compatibility with the PET matrix and are prone to agglomeration during blending, leading to localized stress concentration in the film and deterioration of the film's mechanical properties. The metal-based inorganic pigments commonly used in masterbatches have poor interfacial bonding with PET, resulting in numerous defects at the interface, which easily triggers interfacial oxidation and causes rapid aging under certain aging cycles, severely restricting the long-term weather resistance of PET films. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background art, the purpose of this invention is to provide an aging-resistant masterbatch for thin films and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] An aging-resistant masterbatch for film contains the following components: 25-32 wt% pigment, 0.35-0.48 wt% modified anti-aging agent, 1.2-1.6 wt% dispersant, 0.1-0.12 wt% heat stabilizer, and 2.8-3.6 wt% lubricant, with the balance being PET resin.

[0007] The modified anti-aging agent is prepared by the following method:

[0008] Step A1: Tetramethylpiperidineamine, 3-bromopropanol and dioxane are mixed and purged with dry nitrogen gas for protection. Potassium hydroxide is added, the temperature is raised to 85-100℃, and the mixture is stirred for 3-4 hours. After cooling and filtration to remove potassium hydroxide, dioxane is removed by vacuum distillation to obtain the intermediate.

[0009] Furthermore, the feed ratio of tetramethylpiperidineamine, 3-bromopropanol, potassium hydroxide, and dioxane is 0.1 mol: 0.2 mol: 10⁻¹³ g: 150-200 mL. Potassium hydroxide acts as an alkaline absorbent, promoting the active amino substitution of 3-bromopropanol with tetramethylpiperidineamine. The specific reaction route is as follows:

[0010]

[0011] Step A2: Mix the intermediate, triethylamine and anhydrous tetrahydrofuran, purge with dry nitrogen, control the temperature in an ice-water bath to not exceed 10°C, slowly add oxaloyl chloride monoethyl ester and stir for 1-1.5 h, then raise the temperature to 40-50°C and continue stirring for 2-3 h. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified anti-aging agent.

[0012] Furthermore, the feed ratio of the intermediate, oxaloyl chloride monoethyl ester, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 0.2 mol: 20-30 mL: 200-280 mL. Triethylamine acts as an acid-binding agent, promoting the esterification of oxaloyl chloride monoethyl ester with the active alcohol hydroxyl groups introduced in the intermediate molecule to form a double-chain diester structure. The specific reaction route is as follows:

[0013]

[0014] Furthermore, the dispersant is polyester wax, which has a good lubricating and dispersing effect on inorganic pigments in the PET matrix.

[0015] Furthermore, the heat stabilizer is a phosphite antioxidant, which effectively prevents the PET matrix from oxidizing and degrading under high-temperature processing.

[0016] Furthermore, the lubricant is oleic acid amide, which has a good lubricating effect on the PET matrix and is beneficial for granulation molding.

[0017] A method for preparing an aging-resistant masterbatch for thin films includes the following steps:

[0018] Step S1: Premix PET resin, pigment and modified anti-aging agent, then add dispersant, heat stabilizer and lubricant and mix well to obtain compound material;

[0019] Step S2: Feed the compound into a twin-screw extruder, plasticize and extrude it, and then pelletize and dry it to obtain aging-resistant masterbatch.

[0020] Furthermore, the temperature settings for the twin-screw extruder during the plasticizing extrusion process are: Zone 1 260-270℃, Zone 2 270-280℃, Zone 3 280-290℃, and Die 285-295℃.

[0021] The beneficial effects of this invention are:

[0022] This invention introduces a modified anti-aging agent into PET-based masterbatches. The agent is formed by replacing 3-bromopropanol with tetramethylpiperidineamine to form an intermediate, which is then esterified with the active alcohol hydroxyl group introduced into the intermediate molecule by oxaloyl chloride monoethyl ester, forming a double-chain diester structure. Compared with existing hindered amine antioxidants, the double-chain diester structure exhibits excellent compatibility with PET and is easily dispersed during blending. Especially in film materials, it has minimal impact on the mechanical properties of the film. The tertiary amine-containing double-chain diester structure forms a chelating effect, chelating with metal-based pigments during blending, efficiently scavenging interfacial free radicals in situ, effectively slowing down interfacial aging, and forming a long-lasting anti-aging effect. Furthermore, thanks to the chelating and compounding effect, the surface of the metal-based pigments is modified, improving pigment dispersibility and resulting in more uniform dyeing of the film material by the masterbatch. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1: Preparation of aging-resistant masterbatch for thin films, as detailed below:

[0025] (1) Preparation of modified anti-aging agents

[0026] Step A1: Tetramethylpiperidineamine, 3-bromopropanol and dioxane were mixed and purged with dry nitrogen gas for protection. Potassium hydroxide was added, and the mixture was heated to 85°C and stirred for 4 hours. The ratio of tetramethylpiperidineamine, 3-bromopropanol, potassium hydroxide and dioxane was 0.1 mol: 0.2 mol: 10 g: 150 mL. The mixture was cooled and filtered to remove potassium hydroxide, and then dioxane was removed by vacuum distillation to obtain the intermediate.

[0027] Step A2: Mix the intermediate, triethylamine, and anhydrous tetrahydrofuran, purge with dry nitrogen, and control the temperature in an ice-water bath to no higher than 10°C. Slowly add oxaloyl chloride monoethyl ester and stir for 1.5 h. Then raise the temperature to 40°C and continue stirring for 3 h. The ratio of the intermediate, oxaloyl chloride monoethyl ester, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 0.2 mol: 20 mL: 200 mL. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified anti-aging agent.

[0028] (2) Preparation of color masterbatch

[0029] Step S1: Mix the ingredients according to the following composition: 25 wt% pigment, cobalt blue; 0.35 wt% modified anti-aging agent, self-made in this embodiment; 1.2 wt% dispersant, Licowax OP type polyester wax; 0.12 wt% heat stabilizer, phosphite antioxidant 168; 2.8 wt% lubricant, oleamide; the balance is PET resin, TRN-8580FC5 type resin raw material; first, add PET resin, pigment and modified anti-aging agent to a high-speed mixer for premixing, then add dispersant, heat stabilizer and lubricant and mix well to obtain the compound.

[0030] Step S2: Feed the compound into a twin-screw extruder and set the temperature parameters as follows: Zone 1 260℃, Zone 2 270℃, Zone 3 280℃, and Die 285℃. Plasticize and extrude the compound, then pelletize it with a water ring and dry it to obtain aging-resistant masterbatch.

[0031] Example 2: Preparation of aging-resistant masterbatch for thin films, as detailed below:

[0032] (1) Preparation of modified anti-aging agents

[0033] Step A1: Tetramethylpiperidineamine, 3-bromopropanol and dioxane were mixed and purged with dry nitrogen gas for protection. Potassium hydroxide was added, and the mixture was heated to 100°C and stirred for 3 hours. The ratio of tetramethylpiperidineamine, 3-bromopropanol, potassium hydroxide and dioxane was 0.1 mol: 0.2 mol: 13 g: 200 mL. The mixture was cooled and filtered to remove potassium hydroxide, and then dioxane was removed by vacuum distillation to obtain the intermediate.

[0034] Step A2: Mix the intermediate, triethylamine, and anhydrous tetrahydrofuran, purge with dry nitrogen, and control the temperature in an ice-water bath to no higher than 10°C. Slowly add oxaloyl chloride monoethyl ester and stir for 1 hour. Then raise the temperature to 50°C and continue stirring for 2 hours. The ratio of the intermediate, oxaloyl chloride monoethyl ester, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 0.2 mol: 30 mL: 280 mL. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified anti-aging agent.

[0035] (2) Preparation of color masterbatch

[0036] Step S1: Prepare the ingredients according to the following composition: 32 wt% pigment, cobalt blue; 0.48 wt% modified anti-aging agent, self-made in this embodiment; 1.6 wt% dispersant, Licowax OP type polyester wax; 0.1 wt% heat stabilizer, phosphite antioxidant 168; 3.6 wt% lubricant, oleamide; the balance is PET resin, TRN-8580FC5 type resin raw material. First, add PET resin, pigment and modified anti-aging agent to a high-speed mixer for premixing, then add dispersant, heat stabilizer and lubricant and mix well to obtain the compound.

[0037] Step S2: Feed the compound into a twin-screw extruder and set the temperature parameters as follows: Zone 1 270℃, Zone 2 280℃, Zone 3 290℃, and Die 295℃. Plasticize and extrude the compound, then pelletize it with a water ring and dry it to obtain aging-resistant masterbatch.

[0038] Example 3: Preparation of aging-resistant masterbatch for thin films, as detailed below:

[0039] (1) Preparation of modified anti-aging agents

[0040] Step A1: Tetramethylpiperidineamine, 3-bromopropanol and dioxane were mixed and purged with dry nitrogen gas for protection. Potassium hydroxide was added, and the mixture was heated to 90°C and stirred for 3.8 h. The ratio of tetramethylpiperidineamine, 3-bromopropanol, potassium hydroxide and dioxane was 0.1 mol: 0.2 mol: 12 g: 180 mL. The mixture was cooled and filtered to remove potassium hydroxide, and then dioxane was removed by vacuum distillation to obtain the intermediate.

[0041] Step A2: Mix the intermediate, triethylamine, and anhydrous tetrahydrofuran, purge with dry nitrogen, and control the temperature in an ice-water bath to no higher than 10°C. Slowly add oxaloyl chloride monoethyl ester and stir for 1.2 h. Then raise the temperature to 45°C and continue stirring for 2.6 h. The ratio of the intermediate, oxaloyl chloride monoethyl ester, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 0.2 mol: 25 mL: 240 mL. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified anti-aging agent.

[0042] (2) Preparation of color masterbatch

[0043] Step S1: Prepare the ingredients according to the following composition: 30 wt% pigment, cobalt blue; 0.4 wt% modified anti-aging agent, self-made in this embodiment; 1.5 wt% dispersant, Licowax OP type polyester wax; 0.1 wt% heat stabilizer, phosphite antioxidant 168; 3.2 wt% lubricant, oleamide; the balance is PET resin, TRN-8580FC5 type resin raw material. First, add PET resin, pigment and modified anti-aging agent to a high-speed mixer for premixing, then add dispersant, heat stabilizer and lubricant and mix well to obtain the compound.

[0044] Step S2: Feed the compound into a twin-screw extruder and set the temperature parameters as follows: Zone 1 260℃, Zone 2 270℃, Zone 3 280℃, and Die 285℃. Plasticize and extrude the compound, then pelletize it with a water ring and dry it to obtain aging-resistant masterbatch.

[0045] Example 4: Preparation of aging-resistant masterbatch for thin films, as detailed below:

[0046] (1) Preparation of modified anti-aging agents

[0047] Step A1: Tetramethylpiperidineamine, 3-bromopropanol and dioxane were mixed and purged with dry nitrogen gas for protection. Potassium hydroxide was added, and the mixture was heated to 95°C and stirred for 3.5 h. The ratio of tetramethylpiperidineamine, 3-bromopropanol, potassium hydroxide and dioxane was 0.1 mol: 0.2 mol: 12 g: 170 mL. The mixture was cooled and filtered to remove potassium hydroxide, and then dioxane was removed by vacuum distillation to obtain the intermediate.

[0048] Step A2: Mix the intermediate, triethylamine, and anhydrous tetrahydrofuran, purge with dry nitrogen, and control the temperature in an ice-water bath to no higher than 10°C. Slowly add oxaloyl chloride monoethyl ester and stir for 1.5 h. Then raise the temperature to 405°C and continue stirring for 2.2 h. The ratio of the intermediate, oxaloyl chloride monoethyl ester, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 0.2 mol: 30 mL: 260 mL. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified anti-aging agent.

[0049] (2) Preparation of color masterbatch

[0050] Step S1: Prepare the ingredients according to the following composition: 30 wt% pigment, cobalt blue; 0.43 wt% modified anti-aging agent, self-made in this embodiment; 1.4 wt% dispersant, Licowax OP type polyester wax; 0.11 wt% heat stabilizer, phosphite antioxidant 168; 3.2 wt% lubricant, oleamide; the balance is PET resin, TRN-8580FC5 type resin raw material. First, add PET resin, pigment and modified anti-aging agent to a high-speed mixer for premixing, then add dispersant, heat stabilizer and lubricant and mix well to obtain the compound.

[0051] Step S2: Feed the compound into a twin-screw extruder and set the temperature parameters as follows: Zone 1 270℃, Zone 2 280℃, Zone 3 290℃, and Die 295℃. Plasticize and extrude the compound, then pelletize it with a water ring and dry it to obtain aging-resistant masterbatch.

[0052] Comparative Example 1, referring to Example 4, replaces the modified anti-aging agent with an equal amount of light stabilizer HA-18, and the rest of the implementation process is exactly the same.

[0053] Comparative Example 2, referring to Example 4, replaces the modified anti-aging agent with an equal amount of light stabilizer 770, and the rest of the implementation process is exactly the same.

[0054] The masterbatch prepared above was hot-pressed into sheet samples and subjected to aging tests according to GB / T 14522-2008 standard. The test temperature was 55℃ and the ultraviolet irradiation intensity was 5000μW / cm². 2 The color difference ΔE was tested according to ISO 11664-4:2019 standard, as shown in Table 1:

[0055] Table 1

[0056] ΔE(168h) ΔE(336h) ΔE(504h) ΔE(672h) Example 1 0.16 0.47 0.85 1.36 Example 2 0.11 0.43 0.71 1.02 Example 3 0.15 0.51 0.92 1.21 Example 4 0.13 0.48 0.77 1.10 Comparative Example 1 0.26 0.94 1.73 2.54 Comparative Example 2 0.18 1.05 1.42 1.95

[0057] As can be seen from the test data in Table 1, the color difference of the masterbatch prepared in the example is uniform during aging, and after 4 weeks of accelerated aging, the color difference is significantly lower than that of the comparative example, indicating a stable and long-lasting anti-aging effect.

[0058] To test the film performance of the masterbatch, the masterbatch from Examples 4, 1, and 2 were blended with PET resin at a concentration of 10 wt% and extruded, then calendered into films. Tensile tests were performed according to GB / T13022-1991 standard, and the maximum color difference ΔEmax was measured at 5 points on the film according to ISO 11664-4:2019, as shown in Table 2.

[0059] Table 2

[0060] Tensile strength / MPa Elongation at break / % ΔEmax Example 4 69.42 112.9 0.073 Comparative Example 1 66.19 107.4 0.105 Comparative Example 2 64.37 102.6 0.147

[0061] As shown in Table 2, the color masterbatch of Example 4 has little impact on the mechanical properties of the film when applied to the film material, with extremely low maximum color difference and more uniform coloring.

[0062] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0063] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A film-grade aging-resistant masterbatch, characterized in that, The specific components are: 25-32 wt% pigment, 0.35-0.48 wt% modified anti-aging agent, 1.2-1.6 wt% dispersant, 0.1-0.12 wt% heat stabilizer, and 2.8-3.6 wt% lubricant, with the balance being PET resin; The modified anti-aging agent is prepared by the following method: Step A1: Tetramethylpiperidineamine, 3-bromopropanol and dioxane are mixed and purged with dry nitrogen gas for protection. Potassium hydroxide is added, the temperature is raised to 85-100℃, and the mixture is stirred for 3-4 hours. After cooling and filtration to remove potassium hydroxide, dioxane is removed by vacuum distillation to obtain the intermediate. Step A2: Mix the intermediate, triethylamine and anhydrous tetrahydrofuran, purge with dry nitrogen, control the temperature in an ice-water bath to not exceed 10°C, slowly add oxaloyl chloride monoethyl ester and stir for 1-1.5 h, then raise the temperature to 40-50°C and continue stirring for 2-3 h. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified anti-aging agent. The feed ratio of tetramethylpiperidineamine, 3-bromopropanol, potassium hydroxide and dioxane is 0.1mol:0.2mol:10-13g:150-200mL; The feed ratio of intermediate, oxaloyl chloride monoethyl ester, triethylamine and anhydrous tetrahydrofuran is 0.1 mol: 0.2 mol: 20-30 mL: 200-280 mL; The dispersant is polyester wax; The heat stabilizer is a phosphite antioxidant; The lubricant is oleic acid amide.

2. A method for preparing an aging-resistant masterbatch for thin films according to claim 1, characterized in that, Includes the following steps: Step S1: Premix PET resin, pigment and modified anti-aging agent, then add dispersant, heat stabilizer and lubricant and mix well to obtain compound material; Step S2: Feed the compound into a twin-screw extruder, plasticize and extrude it, and then pelletize and dry it to obtain aging-resistant masterbatch.

3. The method for preparing a film-grade aging-resistant masterbatch according to claim 2, characterized in that, The temperature settings for the twin-screw extruder during the plasticizing extrusion process are: Zone 1 260-270℃, Zone 2 270-280℃, Zone 3 280-290℃, and Die 285-295℃.

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