Flame-retardant anti-aging high-filling modified color master batch and preparation method thereof

Abstract

The invention discloses a flame-retardant anti-aging high-filling modified color master batch and a preparation method thereof, and the color master batch comprises the following components by weight: 20-40 parts of carrier resin; 50-75 parts of a high-filling modified composite filler; 15 to 30 parts of a composite flame retardant; 3-8 parts of an anti-aging auxiliary agent system; 5-20 parts of a coloring agent; and 2-6 parts of a dispersant and a processing aid. The invention has the following technical effects: barium sulfate is adopted to partially or completely replace traditional calcium carbonate, and other modified fillers are combined, so that 50-75 parts of high filling is realized, interference of thermal decomposition of the fillers on flame retardance and aging performance is thoroughly eliminated, and more stable and reliable comprehensive performance is obtained; the inert core and the surface modification layer of barium sulfate can form a denser and firmer heat insulation and oxygen isolation barrier with an intumescent flame retardant system, the flame retardant efficiency is synergistically improved (the dosage of the flame retardant is expected to be reduced), and the flame retardant property reaches UL94 V-2 level.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer material modification, and particularly relates to a flame-retardant and aging-resistant high-filling modified color master batch and a preparation method thereof. BACKGROUND

[0002] The color master batch is an aggregate prepared by uniformly loading excess pigments or dyes in resin, and is a key material for coloring plastic products. With the expansion of the application of plastics in the fields of building, automobile, and electronic appliances, the functional requirements for the color master batch are increasingly improved, especially the performances of flame retardation, aging resistance (ultraviolet resistance and thermal oxygen resistance).

[0003] At present, in order to reduce the cost or endow the material with specific performances (such as rigidity and flame retardation), a large amount of inorganic fillers (high filling) is often added in the color master batch. However, the high filling brings a series of challenges: 1) the fillers are difficult to be uniformly dispersed in the resin matrix and are prone to agglomeration, which affects the coloring power of the color master batch and the mechanical properties of the product; 2) a large amount of fillers can seriously deteriorate the flame retardation performance and the aging resistance performance of the material; 3) when multiple components such as flame retardants, aging aids, fillers, and pigments coexist, interaction is prone to occur, which leads to performance degradation or processing difficulty. In addition, the existing high filling often uses cheap fillers such as calcium carbonate, but the calcium carbonate may decompose and release gas at high temperature, which interferes with the structure of the flame-retardant carbon layer and has a potential negative impact on the long-term thermal stability. Therefore, it is an urgent technical problem to develop a high-filling color master batch that uses a more stable filler system and can synergistically improve the flame retardation and aging resistance performance. SUMMARY

[0004] In order to overcome the defects of the prior art, the purpose of the present application is to provide a flame-retardant and aging-resistant high-filling modified color master batch and a preparation method thereof. The color master batch uses a specific modified composite filler system such as barium sulfate, and produces excellent synergy with the composite flame retardant and the aging resistance aid, so that more stable and durable flame retardation and aging resistance performance are obtained while high filling and low cost are achieved.

[0005] The technical solutions adopted by the present application to solve the technical problems are as follows: According to one aspect of the present application, a flame-retardant and aging-resistant high-filling modified color master batch is designed, which comprises the following components in parts by weight: Carrier resin: 20-40 parts; High-filling modified composite filler: 50-75 parts; Composite flame retardant: 15-30 parts; Aging resistance aid system: 3-8 parts; Coloring agent: 5-20 parts; Dispersing agent and processing aid: 2-6 parts.

[0006] To better address the aforementioned technical deficiencies, the present invention also provides a more advanced technical solution: In some embodiments, the carrier resin is one or more of polyethylene, polypropylene, ethylene-vinyl acetate copolymer, and polyamide, and its weight is 25 parts, 30 parts, or 35 parts. The high-filler modified composite filler also includes barium sulfate, talc, and aluminum hydroxide that have undergone surface modification treatment. The weight parts of barium sulfate, talc, and aluminum hydroxide are 15 parts, 25 parts, and 15 parts, respectively, or 10 parts, 25 parts, and 15 parts, respectively, or 20 parts each.

[0007] The surface modifier of the highly filled modified composite filler is a titanate coupling agent, an aluminate coupling agent, or a silane coupling agent.

[0008] In some embodiments, the composite flame retardant is composed of an intumescent flame retardant and a synergistic flame retardant, wherein the intumescent flame retardant is a compound system of ammonium polyphosphate, pentaerythritol, and melamine, with weight parts of 12 parts, 4 parts, and 2 parts, or weight parts of 15 parts, 5 parts, and 3 parts, or weight parts of 18 parts, 6 parts, and 4 parts, and the synergistic flame retardant is one or more of zinc borate and organically modified montmorillonite, with weight parts of 2 parts.

[0009] In some embodiments, the anti-aging additive system includes a primary antioxidant, a secondary antioxidant, and a light stabilizer, with weight parts of 0.5 parts, 0.5 parts, and 1.0 parts, respectively. The primary antioxidant is a hindered phenolic antioxidant, the secondary antioxidant is a phosphite or thioester antioxidant, and the light stabilizer is a hindered amine light stabilizer.

[0010] In some embodiments, the colorant is an inorganic pigment, an organic pigment, or a mixture of both. The inorganic pigment is selected from at least one of rutile titanium dioxide, iron oxide pigments, and carbon black, and its weight is 8 parts, 10 parts, or 15 parts. The dispersant and processing aid include one or more of polyethylene wax, oxidized polyethylene wax, stearate, and ethylene bis-stearamide, and its weight is 3 parts.

[0011] According to another aspect of the present invention, a method for preparing the flame-retardant and aging-resistant highly filled modified color masterbatch is provided, comprising the following steps: S1: Pretreatment: Dry the highly filled modified composite filler at 80-120℃ for 2-4 hours, and dry the carrier resin and colorant at 70-90℃ for 1-3 hours; S2: Premix: The dried carrier resin, highly filled modified composite filler, composite flame retardant, aging resistant additive system, colorant, dispersant and processing aid are added to a high-speed mixer and mixed at 60-90℃ for 5-15 minutes to obtain a premix. S3: Melt extrusion and granulation: The premixed material is fed into the screw extruder through the main feed port, and after melting, mixing, shearing, extrusion, cooling and pelletizing, the flame-retardant and aging-resistant high-filler modified masterbatch is obtained.

[0012] In some embodiments, in step S3, the screw extruder is a single-screw extruder, comprising: a housing, a screw rotatably disposed within the housing, and a power device for driving the screw to rotate. The housing has a main feed port at the top right end, an extrusion port at the left end, and a heating assembly at the bottom. The screw has a feeding spiral blade at the right end and an extrusion threaded blade at the left end. A material leveling device is disposed between the feeding spiral blade and the extrusion threaded blade, which is fixed to the housing and divides the interior of the housing into a left chamber and a right chamber. The material leveling device is provided with a ring of straight-through mixing holes connecting the left chamber and the right chamber. The straight-through mixing holes are cylindrical. A ring of spiral mixing holes connecting the left chamber and the right chamber is disposed inside and / or outside the ring of straight-through mixing holes. The spiral mixing holes are spiral in shape, and their inlet and outlet are centrally symmetrically arranged.

[0013] In some embodiments, a plurality of transversely equidistant shearing spiral blades are provided between the right side of the material leveling device and the feeding spiral blade, with the right end of the shearing spiral blade located to the right of the left end of the right shearing spiral blade.

[0014] In some embodiments, the inlet at the right end of the straight mixing through-hole and the inlet at the right end of the spiral mixing through-hole are respectively provided with a conical inclined surface.

[0015] In some embodiments, the outer wall of the material leveling device is attached to and fixedly connected to the inner wall of the housing.

[0016] The technical advantages of this invention are as follows: By replacing traditional calcium carbonate with barium sulfate and combining it with other modified fillers, a high filler content of 50-75 parts is achieved while completely eliminating the interference of filler thermal decomposition on flame retardant and aging performance, resulting in more stable and reliable overall performance. The inert core and surface modified layer of barium sulfate can form a denser and stronger heat and oxygen barrier with the intumescent flame retardant system, synergistically improving flame retardant efficiency (potentially reducing the amount of flame retardant used), achieving a flame retardant performance of UL94V-2 level. The combination of barium sulfate with an anti-aging additive system gives the product more durable weather resistance, stronger resistance to ultraviolet radiation and thermo-oxidative aging, and extends the product's outdoor service life.

[0017] By installing a leveling device inside the screw extruder, the premixed material, after melting, is conveyed into and passes through the straight mixing through-hole and the spiral mixing through-hole on the leveling device. Because the straight mixing through-hole is cylindrical and the spiral mixing through-hole is spiral-shaped, with the inlet and outlet centrally symmetrically arranged, the molten material entering through the spiral mixing through-hole at the upper right end of the leveling device can exit from the lower left end of the leveling device and mix with the molten material entering through the straight mixing through-hole at the lower right end of the leveling device and exiting from the lower left end of the leveling device. The molten material entering through the spiral mixing through-hole at the lower right end of the homogenizing device can exit from the upper left end of the homogenizing device and mix with the molten material entering through the straight mixing through-hole at the upper right end of the homogenizing device and exiting from the upper left end of the homogenizing device. When spiral mixing through-holes are set on both the inner and outer sides of a ring of straight mixing through-holes, comprehensive cross-mixing can be achieved, ensuring that high-content fillers, flame retardants, and pigments are fully and uniformly dispersed in the resin, resulting in better mixing effect and avoiding problems such as color difference and spots, with strong and stable coloring power. By setting multiple horizontally equidistant shearing spiral blades on the right side of the homogenizing device, with the right end of the shearing spiral blade located to the right of the left end of its right-side shearing spiral blade, the molten material can be initially sheared and mixed, improving the mixing effect. Attached Figure Description

[0018] Figure 1 A schematic diagram of the structure of a screw extruder according to one embodiment of the present invention; Figure 2 This is a schematic cross-sectional view of a screw extruder. Figure 3 This is a schematic diagram of the screw and the uniform feeding device. Figure 4 This is a schematic diagram of the material leveling device from the right side view. Figure 5 This is a schematic diagram of the material leveling device from the left side view. Figure 6 This is a schematic diagram of the structure of some straight-through mixing holes and spiral mixing holes; Figure label: 1. Shell; 2. Screw; 21. Feeding spiral blade; 22. Extrusion spiral blade; 23. Shearing spiral blade; 3. Power unit; 4. Material leveling device; 41. Straight-through mixing hole; 42. Spiral mixing hole. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0020] This invention provides a flame-retardant and aging-resistant highly filled modified color masterbatch, which, by weight, comprises the following components: Carrier resin: 20-40 parts; High-filler modified composite filler: 50-75 parts; Composite flame retardant: 15-30 parts; Anti-aging additive system: 3-8 parts; Colorant: 5-20 parts; Dispersant and processing aid: 2-6 parts.

[0021] The carrier resin is one or more of polyethylene, polypropylene, ethylene-vinyl acetate copolymer, and polyamide. In this embodiment, the preferred carrier resin is polypropylene, which is 25 parts, 30 parts, or 35 parts by weight.

[0022] The highly filled modified composite filler is barium sulfate, talc, and aluminum hydroxide that have undergone surface modification treatment. The weight parts of barium sulfate, talc, and aluminum hydroxide are 15 parts, 25 parts, and 15 parts, respectively, or 10 parts, 25 parts, and 15 parts, respectively, or 20 parts each. The surface modifier of the highly filled modified composite filler is a titanate coupling agent, an aluminate coupling agent, or a silane coupling agent.

[0023] The composite flame retardant is composed of an intumescent flame retardant and a synergistic flame retardant. The intumescent flame retardant is a compound system of ammonium polyphosphate, pentaerythritol, and melamine, with weight parts of 12 parts, 4 parts, and 2 parts, or weight parts of 15 parts, 5 parts, and 3 parts, or weight parts of 18 parts, 6 parts, and 4 parts. The synergistic flame retardant is one or more of zinc borate and organically modified montmorillonite, preferably zinc borate, with a weight part of 2 parts.

[0024] The anti-aging additive system includes a primary antioxidant, a secondary antioxidant, and a light stabilizer, with weight parts of 0.5 parts, 0.5 parts, and 1.0 parts, respectively. The primary antioxidant is a hindered phenolic antioxidant, specifically antioxidant 1010. The secondary antioxidant is a phosphite or thioester antioxidant, specifically antioxidant 168. The light stabilizer is a hindered amine light stabilizer, specifically light stabilizer 770.

[0025] The colorant is an inorganic pigment, an organic pigment, or a mixture of both. The inorganic pigment is selected from at least one of rutile titanium dioxide, iron oxide pigments, and carbon black, preferably titanium dioxide, and its weight is 8 parts, 10 parts, or 15 parts. The dispersant and processing aid include one or more of polyethylene wax, oxidized polyethylene wax, stearate, and ethylene bis-stearamide, preferably polyethylene wax and calcium stearate, and their weights are 2 parts and 1 part, respectively.

[0026] Specifically, flame-retardant and aging-resistant highly filled modified color masterbatches were prepared according to the formulations (parts by weight) shown in Table 1 below. All inorganic fillers underwent surface modification treatment with titanate coupling agents.

[0027] The preparation method of the aforementioned flame-retardant and aging-resistant highly filled modified masterbatch includes the following steps: S1: Pretreatment: Dry all highly filled modified composite fillers at 80-120℃ for 2-4 hours, preferably in a 100℃ forced-air drying oven for 3 hours; dry the carrier resin and colorant at 70-90℃ for 1-3 hours, preferably PP resin and titanium dioxide at 80℃ for 2 hours.

[0028] S2: Premix: Add the dried carrier resin, highly filled modified composite filler, composite flame retardant, aging resistant additive system, colorant, dispersant and processing aid to a high-speed mixer (1000 rpm) and mix at 60-90℃ for 5-15 minutes to obtain a premix, preferably at 80℃ for 10 minutes.

[0029] S3: Melt extrusion and granulation: The premixed material is fed into the screw extruder from the main feed port, and after melting, mixing, shearing, extrusion, cooling and pelletizing, flame-retardant and aging-resistant high-filler modified masterbatch is obtained.

[0030] In step S3, the screw extruder is a single-screw extruder, as shown in the reference. Figures 1-6The single-screw extruder includes: a housing 1, a screw 2 rotatably disposed within the housing 1, and a power unit 3 for driving the screw 2 to rotate. The power unit 3 consists of a motor and a reducer. The drive shaft of the motor is connected to the input shaft of the reducer, and the output shaft of the reducer is connected to the screw 2. The top right end of the housing 1 has a main feed port, and the left end of the housing 1 has an extrusion port. The bottom of the housing 1 has a heating assembly, which is a conventional heating tube used to heat the housing 1 and melt the material added to the housing 1. The right end of the screw 2 has a feeding spiral blade 21, and the left end has an extrusion thread blade 22. A material leveling device 4 is provided between the feeding spiral blade 21 and the extrusion thread blade 22 to divide the interior of the housing 1 into a left chamber and a right chamber. The outer wall of device 4 is attached to and welded to the inner wall of housing 1 or fixed by bolts. Screw 2 is rotatably engaged with the through hole in the middle of the uniform material device 4. The uniform material device 4 is provided with a ring of straight mixing through holes 41 connecting the left and right chambers. Multiple straight mixing through holes 41 are equidistantly distributed in a circle. A ring of spiral mixing through holes 42 connecting the left and right chambers is provided on the inner and / or outer sides of the ring of straight mixing through holes 41. In this embodiment, preferably, a ring of spiral mixing through holes 42 connecting the left and right chambers is provided on the inner and outer sides of the ring of straight mixing through holes 41, respectively. Multiple spiral mixing through holes 42 are equidistantly distributed in a circle. The spiral mixing through holes 42 are spiral in shape, and their inlets and outlets are centrally symmetrical. Vacuum suction holes communicating with the interior of housing 1 are provided on the left and right sides of the uniform material device 4, respectively. The two vacuum suction holes are connected to a vacuum pump through vacuum tubes to evacuate the interior.

[0031] The inlet at the right end of the straight mixing through-hole 41 and the inlet at the right end of the spiral mixing through-hole 42 are respectively provided with a conical inclined surface.

[0032] Furthermore, multiple transversely equidistant shearing spiral blades 23 are arranged between the right side of the material leveling device 4 and the feeding spiral blade 21. The shearing spiral blades 23 are welded to the screw 2, and the right end of the shearing spiral blade 23 is located to the right of the left end of the shearing spiral blade 23.

[0033] In some embodiments, in order to increase the material shearing and dispersion effect, multiple transversely equidistant second shearing spiral blades are provided between the material leveling device 4 and the extrusion threaded blade 22. The structure of the second shearing spiral blades is similar to that of the shearing spiral blade 23. The second shearing spiral blades are welded to the screw 2, and the distance between adjacent second shearing spiral blades is smaller than the distance between adjacent shearing spiral blades 23.

[0034] The color masterbatches obtained in Examples 1-3 and the comparative example were mixed with homopolymer PP (base resin) at an addition amount of 8%, and injection molded into standard test strips for performance testing. The results are shown in Table 2.

[0035] Table 2 As shown in Table 2, after adopting the composite filler system containing barium sulfate, the masterbatches prepared in Examples 1-3 of this invention all achieved a flame retardancy rating of V-2. Furthermore, their thermal aging and UV aging performance were further improved compared to the original scheme (based on calcium carbonate), with Example 2 exhibiting the best overall performance. This confirms that the introduction of barium sulfate significantly improves the long-term thermal stability and weather resistance of the system. Despite the increased density, the processing flow rate (MFR) remained good. The comparative example (using calcium carbonate and without additives) showed significantly inferior performance, further demonstrating the advantages of the formulation design of this invention.

[0036] Barium sulfate (BaSO4) exhibits extremely high thermal stability (decomposing at >1580℃). Its core function is to act as an inert and stable "skeleton," without participating in decomposition. This avoids the problem of calcium carbonate decomposing at high temperatures and releasing CO2, which would damage the integrity of the flame-retardant char layer. Consequently, it significantly improves the reliability of the flame-retardant effect and its long-term thermal aging stability. In Example 2, the amount of barium sulfate was 15 parts, which is an intermediate value. This provided sufficient stable skeleton effect (supporting a high strength retention rate of 92%), without causing excessive density (1.65 in Example 1) or unnecessary increase in melt viscosity (MFR decreased to 11.0 in Example 1) due to excessive addition (such as 20 parts in Example 1). This allowed the masterbatch to achieve excellent aging resistance and good processability.

[0037] The above descriptions are merely some embodiments of the present invention. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A flame retardant, weatherable, high filled modified color masterbatch, characterized in that, By weight parts, comprising the following components: Carrier resin: 20-40 parts; High filling modified composite filler: 50-75 parts; Composite flame retardant: 15-30 parts; Anti-aging auxiliary system: 3-8 parts; Colorant: 5-20 parts; Dispersant and processing aid: 2-6 parts.

2. The flame retardant, weatherable, high filled modified color masterbatch as claimed in claim 1, wherein, The carrier resin is one or more combinations of polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, the weight parts of which are 25, or 30, or 35; The high filling modified composite filler further comprises surface modified barium sulfate, talcum powder, aluminum hydroxide, the weight parts of which are 15, 25, 15 respectively, or 10, 25, 15 respectively, or all 20.

3. The flame retardant, weatherable, high-filled modified color masterbatch according to claim 1 or 2, characterized in that, The composite flame retardant is composed of intumescent flame retardant and synergistic flame retardant, wherein the intumescent flame retardant is a compounded system of ammonium polyphosphate, pentaerythritol and melamine, the weight parts of which are 12, 4, 2 respectively, or 15, 5, 3 respectively, or 18, 6, 4 respectively, and the synergistic flame retardant is one or more of zinc borate and organically modified montmorillonite, the weight parts of which is 2.

4. The flame retardant, weatherable, high filled modified color masterbatch as claimed in claim 1, wherein, The anti-aging auxiliary system comprises primary antioxidant, auxiliary antioxidant and light stabilizer, the weight parts of which are 0.5, 0.5, 1.0 respectively.

5. The flame retardant, weatherable, high filled modified color masterbatch as claimed in claim 1, wherein, The colorant is inorganic pigment, organic pigment or a mixture of the two, the inorganic pigment is selected from at least one of rutile titanium dioxide, iron oxide pigment and carbon black, the weight parts of which is 8, or 10, or 15; the dispersant and processing aid comprises one or more of polyethylene wax, oxidized polyethylene wax, stearate and ethylene bis-stearamide, the weight parts of which is 3.

6. The method for preparing flame-retardant and aging-resistant highly filled modified color masterbatch according to any one of claims 1-5, characterized in that, Comprising the following steps: S1： Pre-treatment: drying the high filling modified composite filler at 80-120℃ for 2-4 hours, drying the carrier resin and colorant at 70-90℃ for 1-3 hours; S2: premixing: adding the dried carrier resin, high filling modified composite filler, composite flame retardant, anti-aging auxiliary system, colorant and dispersant and processing aid into a high-speed mixer, mixing at 60-90℃ for 5-15 minutes to obtain a premix; S3: melt extrusion and granulation: adding the premix through the main feeding port into a screw extruder, and then going through melting, mixing, shearing, extrusion, cooling and granulation to obtain the flame-retardant and anti-aging high filling modified color master batch.

7. The preparation method according to claim 6, characterized in that, In step S3, the screw extruder is a single screw extruder, which comprises a shell, a screw rotating in the shell, and a power device driving the screw to rotate, the right end top of the shell is provided with a main feeding port, the left end is provided with an extrusion port, the bottom is provided with a heating assembly, the right end of the screw is provided with a feeding spiral blade, the left end is provided with an extrusion thread blade, a uniform feeding device is arranged between the feeding spiral blade and the extrusion thread blade and fixed to the shell, and the shell is divided into a left chamber and a right chamber by the uniform feeding device, a through mixing hole is arranged on the uniform feeding device and communicates with the left chamber and the right chamber, the through mixing hole is in a straight cylinder shape, a spiral mixing hole is arranged on the inner side and / or the outer side of the through mixing hole and communicates with the left chamber and the right chamber, the spiral mixing hole is in a spiral shape, and the inlet and the outlet of the spiral mixing hole are centrally symmetrically arranged.

8. The preparation method according to claim 7, characterized in that, A plurality of transverse equidistantly distributed shearing spiral blades are arranged between the right side of the uniform feeding device and the feeding spiral blade, and the right end of the shearing spiral blade is located to the right of the left end of the shearing spiral blade on the right side.

9. The preparation method according to claim 7, characterized in that, The inlets of the right end of the through mixing hole and the right end of the spiral mixing hole are respectively provided with tapered inclined surfaces.

10. The preparation method according to claim 7, characterized in that, The outer side wall of the uniform feeding device is attached to and fixed to the inner side wall of the shell.

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