High-performance fluorine-containing plastic processing aid and preparation method thereof

Abstract

The invention discloses a high-performance fluorine-containing plastic processing aid. The aid comprises the following components in parts by mass: 90-100 parts of a resin matrix; 0.5 to 5 parts of a fluorine-containing polymer; 1-5 parts of a plasticizer; 0.5 to 3 parts of a lubricant; 0.05 to 0.2 part of an antioxidant; when the fluorine-containing plastic processing aid is added in plastic production, melt fracture can be effectively inhibited, the surface smoothness of a product can be improved, the dispersity of the aid and the compatibility of a matrix can be improved, the processing performance uniformity can be improved, the oxidation resistance of a material can be enhanced, the service life of the product can be prolonged, and the crystal structure can be improved; the mechanical property and the dimensional stability of the product are improved, and the forming processing energy consumption and cost can be obviously reduced.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to a high-performance fluoroplastic processing aid and its preparation method. Background Technology

[0002] Existing plastic materials have the following shortcomings in the production process: 1. When plastics are processed under high temperature and high-speed shear conditions, melt fracture is prone to occur, resulting in cracks, streaks, or roughness on the surface of the product, which seriously affects the appearance quality and performance of the product. 2. Traditional processing aids (such as nucleating agents and lubricants) have poor dispersibility in the plastic matrix and are prone to agglomeration, leading to localized uneven processing performance. 3. Plastics are prone to oxidative degradation under high temperature conditions, resulting in discoloration, bubbling, and performance degradation of the product during processing. 4. Traditional nucleating agents have limited effectiveness, resulting in uneven crystal structure after plastic molding, thus affecting the mechanical properties and dimensional stability of the product. Therefore, the company designs and develops a plastic processing aid to meet the production needs of plastic products. Due to process requirements, existing mixing equipment cannot meet production needs, and the company also needs to develop corresponding mixing equipment to solve the production challenges of the new plastic processing aid. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-performance fluoroplastic processing aid and its preparation method.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A high-performance fluoroplastic processing aid, wherein the components of the aid, by weight parts, comprise:

[0006] Resin matrix: 90-100 parts;

[0007] Fluoropolymers: 0.5-5 parts;

[0008] Plasticizer: 1-5 parts;

[0009] Lubricant: 0.5-3 parts;

[0010] Antioxidant: 0.05-0.2 parts;

[0011] Modified nucleating agent: 0.01-1 part.

[0012] Furthermore, the preparation steps of the modified nucleating agent include:

[0013] Step A1: Pre-hydrolysis of silane coupling agent. Add 200 mL of anhydrous ethanol to a beaker, slowly add 0.5–2 g of fluorinated silane coupling agent while stirring, add water with a molar ratio of 1:1 to 1:2 dropwise, and simultaneously add acetic acid to adjust the pH to ≈ 4.5. Stir to pre-hydrolyze and form an active silane system.

[0014] Step A2: Silane-coated boron nitride. 100 g of boron nitride powder is slowly added to the silane solution prepared in step A1. First, the solution is stirred with a high-speed disperser, and then ultrasonically dispersed in a water bath to promote silane bonding.

[0015] Step A3: Organic polyamine post-treatment coating. Add 0.2–1 g of diethylenetriamine or PEI aqueous solution, adjust the pH to 6–7, and stir for 30 minutes to allow the polyamine groups to react with the amino / hydroxyl active sites.

[0016] Step A4: Separation and drying. Remove unreacted components with a cleaning agent, then dry in a vacuum drying oven. Crush and sieve the dried sample powder to obtain the finished product for later use.

[0017] Furthermore, the resin matrix is ​​linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, or polypropylene; the fluoropolymer is polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene propylene, or fluororubber; the plasticizer is polyethylene glycol, phthalate, or polycaprolactone; the lubricant is molybdenum disulfide, zinc stearate, or calcium stearate; and the antioxidant is hindered phenolic antioxidant or phosphite antioxidant.

[0018] Furthermore, in step A1, the temperature of the stirring pre-hydrolysis is controlled below 40°C, and the stirring pre-hydrolysis time is controlled at 30 minutes.

[0019] Furthermore, in step A2, the stirring speed of the high-speed disperser is controlled at 2000–3000 rpm, the stirring time is controlled at 30–60 minutes, the water bath temperature is controlled at 60–80℃, and the water bath dispersion time is controlled at 30 minutes.

[0020] Furthermore, the cleaning agent in step A4 is a 1:1 mixture of ethanol-water and anhydrous ethanol. The cleaning steps are to wash twice with 1:1 ethanol-water and then wash once with anhydrous ethanol. The drying temperature of the vacuum drying oven is controlled at 60–80°C and the drying time of the vacuum drying oven is controlled at 8–12 hours.

[0021] A method for preparing a high-performance fluoroplastic processing aid, applicable to the preparation of a high-performance fluoroplastic processing aid, includes the following steps:

[0022] Step S1: Weigh the resin matrix, fluoropolymer, plasticizer, lubricant, antioxidant and nucleating agent according to the proportion, and then put them into the mixing device and mix them evenly.

[0023] Step S2: Input the mixed material from step S1 into a twin-screw extruder for melt blending;

[0024] Step S3: Cool the material after melt blending in step S2, and then use a pelletizer to cut the material into granular finished products.

[0025] Furthermore, the mixing time in step S1 is controlled to be 15-30 minutes.

[0026] Furthermore, in step S2, the melt blending temperature is controlled at 180-300℃, and the screw speed is controlled at 50-200 rpm.

[0027] Furthermore, the particle size of the finished product in step S3 is controlled to be 3-5 mm.

[0028] The beneficial effects of this invention are:

[0029] This invention provides a fluoroplastic processing aid that, when added to plastic production, can effectively inhibit melt fracture, improve the surface smoothness of products, enhance the dispersibility and matrix compatibility of the aid, improve the uniformity of processing performance, enhance the oxidation resistance of materials, extend product lifespan, improve the crystal structure, improve the mechanical properties and dimensional stability of products, and significantly reduce molding and processing energy consumption and costs. Attached Figure Description

[0030] Figure 1 This is a flowchart illustrating the preparation process of a high-performance fluoroplastic processing aid in this embodiment.

[0031] Figure 2 This is a flowchart illustrating the preparation of a modified nucleating agent in this embodiment;

[0032] Figure 3 This is a schematic diagram of the structure of a mixing device in this embodiment;

[0033] Figure 4 This is a schematic diagram of the elastic push rod element in this embodiment;

[0034] Figure 5 for Figure 3 Enlarged view of point A in the image.

[0035] Reference numerals: Tank body 1, Mixing chamber 11, Main feeding pipe 12, Support frame 13, Conical slope 14, Discharge port 141, Stirring mechanism 15, Frame-shaped stirring blade assembly 151, Tank cover 2, Auxiliary feeding pipe 21, Sprinkler 3, Storage chamber 31, Filter layer 32, Feed pipe 33, Hose section 331, Elastic support element 34, Support column 341, First spring 342, Cap head 35, Vibrator 4, Cam 41, Elastic push rod element 42, Rod box 421, Push rod 422, Piston 423, Second spring 424, Top block 425. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] A high-performance fluoroplastic processing aid, comprising the following components by mass parts:

[0038] Resin matrix: 90-100 parts;

[0039] Fluoropolymers: 0.5-5 parts;

[0040] Plasticizer: 1-5 parts;

[0041] Lubricant: 0.5-3 parts;

[0042] Antioxidant: 0.05-0.2 parts;

[0043] Modified nucleating agent: 0.01-1 part.

[0044] In this invention, the resin matrix is ​​selected from linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), or polypropylene (PP); the fluoropolymer is selected from polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), polytetrafluoroethylene propylene (FEP), or fluororubber (FKM); the plasticizer is selected from polyethylene glycol (PEG), phthalate, or polycaprolactone; the lubricant is selected from molybdenum disulfide, zinc stearate, or calcium stearate; and the hindered phenolic antioxidant (antioxidant 1010) or phosphite antioxidant (antioxidant 168) is selected.

[0045] The modified nucleating agent in the additives of this invention is a key innovative product, such as... Figure 2 The preparation steps of a modified nucleating agent shown include:

[0046] Step A1: Pre-hydrolysis of silane coupling agent. Add 200 mL of anhydrous ethanol to a beaker, and slowly add 0.5–2 g of fluorinated silane coupling agent while stirring. Add water at a molar ratio of 1:1 to 1:2 dropwise, and simultaneously add acetic acid to adjust the pH to ≈ 4.5. Stir and pre-hydrolyze to form an active silane system. The temperature of stirring and pre-hydrolysis in step A1 is controlled below 40℃, and the stirring and pre-hydrolysis time is controlled at 30 minutes. After hydrolysis, the fluorinated silane bonds with the hydroxyl groups on the surface of the nucleating agent to form a dense fluorocarbon chain layer. This layer has extremely low surface tension and is highly compatible with fluoropolymers such as PTFE and FEP.

[0047] Step A2: Silane-coated boron nitride. 100 g of boron nitride powder is slowly added to the silane solution prepared in step A1. First, the solution is stirred using a high-speed disperser, and then ultrasonically dispersed in a water bath to promote silane bonding. In step A2, the stirring speed of the high-speed disperser is controlled at 2000–3000 rpm, the stirring time is controlled at 30–60 minutes, the water bath temperature is controlled at 60–80℃, and the water bath dispersion time is controlled at 30 minutes.

[0048] Step A3: Organic polyamine post-treatment coating. Add 0.2–1 g of diethylenetriamine or PEI aqueous solution, adjust the pH to 6–7, and stir for 30 minutes to allow the polyamine groups to react with the amino / hydroxyl active sites. The polyamine molecules (such as PEI or DETA) form a complex coating with the silane layer through hydrogen bonding, coordination, or reaction, providing abundant polar functional groups (-NH2, -NH-) to enhance the interfacial bonding between the nucleating agent and the non-polar polyolefin matrix such as PE and PP.

[0049] Step A4: Separation and drying. Unreacted components are removed with a cleaning agent, and then dried in a vacuum drying oven. The dried sample powder is pulverized and sieved to obtain the finished product for later use. The cleaning agent in step A4 is a 1:1 mixture of ethanol-water and anhydrous ethanol. The cleaning steps are: first wash twice with 1:1 ethanol-water, and then wash once with anhydrous ethanol. The drying temperature of the vacuum drying oven is controlled at 60–80℃, and the drying time of the vacuum drying oven is controlled at 8–12 hours.

[0050] Steps A3 and A4 create a double coating effect, forming a "fluorine-repellent on the outside and olefin-friendly on the inside" functional interface. This aims to achieve the following in processing aids: synergistic dispersion with fluorine-containing microparticles, good dispersion and stable distribution in polyolefin melts, and avoidance of agglomeration, migration and thermal instability.

[0051] The modified nucleating agent of this invention, prepared by a double-coating method, has a dual modification mechanism. Its technical advantages are: 1. It improves the dispersibility and compatibility of the nucleating agent in the polyolefin matrix, inhibits particle agglomeration, and improves the uniformity and smoothness of the pipe surface; 2. It enhances the synergistic effect of processing aids and fluorinated additives such as PTFE, avoids phase boundary desorption, forms a more stable "processing channel," and effectively inhibits melt fracture; 3. It improves the processing stability of polyolefins under high-shear conditions such as extrusion and blown film, and significantly reduces melt pressure fluctuations; 4. It improves the mechanical and apparent properties of the product, such as tensile strength, surface gloss, and transparency, all of which are significantly improved.

[0052] like Figure 1 The method for preparing a high-performance fluoroplastic processing aid, as shown, includes the following steps:

[0053] Step S1: Weigh the resin matrix, fluoropolymer, plasticizer, lubricant, antioxidant, and nucleating agent according to the proportion, and then put them into the mixing device and mix them evenly. The mixing time in step S1 is controlled at 15-30 minutes, and the mixing uniformity is greater than 90%.

[0054] Step S2: Input the mixed material from step S1 into a twin-screw extruder for melt blending. The melt blending temperature in step S2 is controlled at 180-300℃, and the screw speed is controlled at 50-200 rpm.

[0055] Step S3: Cool the material after melting and blending in step S2. After cooling, use a pelletizer to cut the material into granular finished products. The particle size of the finished products in step S3 is controlled to be 3-5 mm.

[0056] The present invention discloses a high-performance fluoroplastic processing aid for the production of plastic products. The method of use is as follows: the processing aid of the present invention is added to the target plastic matrix at a dosage of 0.1%-5% of the weight of the target plastic matrix, the mixing temperature is controlled at 160℃-250℃, and the plastic product is formed by injection molding, extrusion, blown film or calendering.

[0057] Using a high-performance fluoroplastic processing aid of the present invention to process and produce plastic products has the following advantages:

[0058] 1. Effectively inhibits melt fracture and improves the surface smoothness of products.

[0059] Adding fluoropolymers as rheology modifiers can form an interfacial lubricating layer in the matrix melt, reducing melt viscosity and processing shear force to suppress melt fracture.

[0060] 2. Improves the dispersibility and matrix compatibility of additives, and enhances the uniformity of processing performance.

[0061] Adding modified nucleating agent components enables the nucleating agent to form chemical bonds with the surface of the matrix material, improving its dispersibility and compatibility, and preventing the nucleating agent from agglomerating.

[0062] 3. Enhances the oxidation resistance of materials and extends product lifespan.

[0063] The addition of antioxidants significantly delays the oxidative degradation of the matrix material under high-temperature conditions, improves the thermal stability of plastic products, and extends the product's service life.

[0064] 4. Improves crystal structure, enhances mechanical properties and dimensional stability.

[0065] The modified nucleating agent forms a strong interaction force with the surface of the matrix material, which significantly improves the crystallization rate and crystal structure uniformity of the material. The optimized formulation of the nucleating agent and the synergistic effect of the fluorinated coupling agent significantly improve the tensile strength, impact strength and dimensional stability of the finished product after crystallization.

[0066] 5. Significantly reduces energy consumption and costs in molding and processing.

[0067] The interfacial lubrication effect of fluoropolymers and the uniform dispersion of nucleating agents reduce the shear force and processing temperature required during material processing, improve melt fluidity during molding, reduce equipment load, and shorten processing cycle.

[0068] In the preparation method of a high-performance fluoroplastic processing aid of the present invention, the mixing process in step S1 is a very important step. It is necessary to mix all the auxiliary components evenly with a mixing uniformity of more than 90%. For this purpose, the present invention has specially designed a mixing device to meet the mixing requirements.

[0069] like Figures 3-5The mixing device shown includes a tank body 1, a tank cover 2, and a dispenser 3. The tank cover 2 is connected to the top of the tank body 1. The tank body 1 has a mixing chamber 11 inside. The dispenser 3 is movably installed on the top of the mixing chamber 11 and has a storage chamber 31 inside the dispenser 3. An auxiliary feeding pipe 21 is installed on the top of the tank cover 2, and the auxiliary feeding pipe 21 is connected to the storage chamber 31. A filter layer 32 is installed at the bottom of the storage chamber 31. A main feeding pipe 12 is installed on the side wall of the tank body 1, and the main feeding pipe 12 is connected to the mixing chamber 11 and located below the dispenser 3. 2. A vibrator 4 is installed, which is connected to the distributor 3. The vibrator 4 drives the distributor 3 to vibrate, so that the additive powder in the storage chamber 31 forms a spraying effect. In this invention, the main component of the additive is the resin matrix, accounting for more than 90%. Therefore, the resin matrix is ​​fed through the main feeding pipe 12. A stirring mechanism 15 is installed at the bottom of the tank 1. The stirring mechanism 15 includes a rotatably mounted frame-shaped stirring blade assembly 151. The continuous rotation of the frame-shaped stirring blade assembly 151 continuously agitates the resin matrix material. Other... Since the additive materials constitute a small proportion and are all powders, this invention designs a method for feeding them through auxiliary feeding pipe 21. Other additive components first enter the dispenser 3, where they are sprayed while the dispenser 3 is vibrating. This spraying process helps to evenly disperse the other additive components within the main components, resulting in a final mixture uniformity greater than 90%. For ease of feeding, two auxiliary feeding pipes 21 are symmetrically installed on the top of the can lid 2. Correspondingly, two symmetrical feed pipes 33 are connected to the top of the dispenser 3, and these feed pipes 33 connect to the storage chamber. 31. A flexible hose section 331 is connected between the feed pipe 33 and the auxiliary feed pipe 21. The flexible hose section 331 is designed to cooperate with the vibration movement of the dispenser 3 to prevent pipe breakage. Vibration can also ensure that all residual material in the flexible hose section 331 is fed in. The filter layer 32 has the effect of filtering and falling powder, which can break up the agglomerated additive components and form a powder falling effect. The falling of the filter makes the additive components more dispersed and helps to mix evenly. A hand operation hole should be opened on the can lid 2 of the present invention to facilitate the connection and other operations.

[0070] like Figure 3 and Figure 5 As shown, a ring of support frame 13 is fixedly installed on the inner wall of the tank body 1. At least two symmetrically arranged elastic support elements 34 are installed at the bottom of the sprayer 3. The sprayer 3 is installed on the support frame 13 through the elastic support elements 34. The elastic support element 34 includes a support column 341 and a first spring 342. The support column 341 is vertically connected to the bottom of the sprayer 3 and is installed through the support frame 13. The first spring 342 is fitted on the outside of the support column 341 and installed between the bottom of the sprayer 3 and the support frame 13. The bottom of the support column 341 is connected to a limit switch to prevent the sprayer 3 from excessively springing. A cap 35 is installed on the top of the sprayer 3 to drive the vibrator 4 and achieve a vibration drive effect.

[0071] like Figure 3 and Figure 4 As shown, the vibrator 4 includes a cam 41 and an elastic push rod element 42. The cam 41 is rotatably mounted on the top of the outer side of the tank cover 2 and is connected to a motor for driving. The elastic push rod element 42 is mounted on the inner side of the tank cover 2 and includes a rod box 421 and a push rod 422. The rod box 421 is fixedly connected to the top of the inner side of the tank cover 2, and the push rod 422 is installed vertically through the rod box 421. The top end of the push rod 422 extends upward through the tank cover 2 and contacts the outer edge of the cam 41. The bottom end of the push rod 422 is connected to a top block 425, which abuts against the cap 35 in the dispenser 3. The outer wall of the push rod 422 is fixedly connected to... A piston 423 is fitted and installed inside the rod box 421, serving as a guide for the movement of the push rod 422. A second spring 424 is pressed and installed below the piston 423. The elastic force of the second spring 424 ensures that the push rod 422 is always in contact with the outer edge of the cam 41. The cam 41 has a smooth section and a convex section. During the rotation of the cam 41, the push rod 422 can be raised and lowered. During the up-and-down movement of the push rod 422, it can push the sprayer 3 to rise and fall. The sprayer 3 forms a regular vibration effect, and the powder on the filter layer 32 can be continuously sprayed and mixed into the main component of the additive below.

[0072] like Figure 3 As shown, the bottom of the tank 1 is provided with a conical slope 14, which facilitates material concentration. The tank 1 is made of stainless steel to prevent material adhesion. The bottom side of the conical slope 14 is provided with a discharge port 141 to facilitate discharge operation. After the additive components are mixed evenly in the mixing device of the present invention, they are discharged and output to the twin-screw extruder for melt blending.

[0073] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A high-performance fluoroplastic processing aid, characterized in that, The components of the additive, by mass parts, include: Resin matrix: 90-100 parts; Fluoropolymers: 0.5-5 parts; Plasticizer: 1-5 parts; Lubricant: 0.5-3 parts; Antioxidant: 0.05-0.2 parts; Modified nucleating agent: 0.01-1 part.

2. The high-performance fluoroplastic processing aid according to claim 1, characterized in that, The preparation steps of the modified nucleating agent include: Step A1: Pre-hydrolysis of silane coupling agent. Add 200 mL of anhydrous ethanol to a beaker, slowly add 0.5–2 g of fluorinated silane coupling agent while stirring, add water with a molar ratio of 1:1 to 1:2 dropwise, and simultaneously add acetic acid to adjust the pH to ≈ 4.

5. Stir to pre-hydrolyze and form an active silane system. Step A2: Silane-coated boron nitride. 100 g of boron nitride powder is slowly added to the silane solution prepared in step A1. First, the solution is stirred with a high-speed disperser, and then ultrasonically dispersed in a water bath to promote silane bonding. Step A3: Organic polyamine post-treatment coating. Add 0.2–1 g of diethylenetriamine or PEI aqueous solution, adjust the pH to 6–7, and stir for 30 minutes to allow the polyamine groups to react with the amino / hydroxyl active sites. Step A4: Separation and drying. Remove unreacted components with a cleaning agent, then dry in a vacuum drying oven. Crush and sieve the dried sample powder to obtain the finished product for later use.

3. The high-performance fluoroplastic processing aid according to claim 1, characterized in that, The resin matrix is ​​linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene or polypropylene, the fluoropolymer is polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene propylene or fluororubber, the plasticizer is polyethylene glycol, phthalate or polycaprolactone, the lubricant is molybdenum disulfide, zinc stearate or calcium stearate, and the antioxidant is hindered phenolic antioxidant or phosphite antioxidant.

4. The high-performance fluoroplastic processing aid according to claim 2, characterized in that, In step A1, the temperature of the pre-hydrolysis stirring is controlled below 40°C, and the pre-hydrolysis stirring time is controlled at 30 minutes.

5. The high-performance fluoroplastic processing aid according to claim 2, characterized in that, In step A2, the stirring speed of the high-speed disperser is controlled at 2000–3000 rpm, the stirring time is controlled at 30–60 minutes, the water bath temperature is controlled at 60–80℃, and the water bath dispersion time is controlled at 30 minutes.

6. The high-performance fluoroplastic processing aid according to claim 2, characterized in that, The cleaning agent in step A4 is a 1:1 mixture of ethanol-water and anhydrous ethanol. The cleaning steps are to wash twice with 1:1 ethanol-water and then wash once with anhydrous ethanol. The drying temperature of the vacuum drying oven is controlled at 60–80℃ and the drying time of the vacuum drying oven is controlled at 8–12 hours.

7. A method for preparing a high-performance fluoroplastic processing aid, applied to the preparation of a high-performance fluoroplastic processing aid as described in any one of claims 1-6, characterized in that, Includes the following steps: Step S1: Weigh the resin matrix, fluoropolymer, plasticizer, lubricant, antioxidant and nucleating agent according to the proportion, and then put them into the mixing device and mix them evenly. Step S2: Input the mixed material from step S1 into a twin-screw extruder for melt blending; Step S3: Cool the material after melt blending in step S2, and then use a pelletizer to cut the material into granular finished products.

8. The method for preparing a high-performance fluoroplastic processing aid according to claim 7, characterized in that, The mixing time in step S1 is controlled to be 15-30 minutes.

9. The method for preparing a high-performance fluoroplastic processing aid according to claim 7, characterized in that, In step S2, the melt blending temperature is controlled at 180-300℃, and the screw speed is controlled at 50-200 rpm.

10. The method for preparing a high-performance fluoroplastic processing aid according to claim 7, characterized in that, The particle size of the finished product in step S3 is controlled to be 3-5 mm.

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