PVC color masterbatch with high bending resistance and high weather resistance and preparation method thereof
By combining carrier resin, pigment, polyester plasticizer and thermal expansion microspheres, the problem of stress whitening when plastic products are bent is solved, and a high weather resistance effect without reducing mechanical strength is achieved.
Patent Information
- Application Number
- CN202610860076.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-15
- Publication Date
- 2026-07-21
AI Technical Summary
Existing technologies, when used to improve the stress whitening phenomenon in plastic products during bending, tend to lead to a decrease in mechanical strength, and cannot effectively solve this problem without reducing fillers and toughening agents.
A combination of carrier resin, pigment, polyester plasticizer, epoxidized soybean oil and thermally expandable microspheres was used to prepare a PVC color masterbatch with high bending resistance and weather resistance by consuming strain energy through the reversible deformation of the thermally expandable microspheres during bending, combined with the optical masking of pigments and the mechanical improvement of toughening agents.
It achieves a significant reduction in stress whitening without affecting mechanical strength, and significantly improves the weather resistance of plastic products through the reversible deformation of thermally expanded microspheres and the optical masking of pigments.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of color masterbatch technology, and in particular to a PVC color masterbatch with high bending resistance and weather resistance and its preparation method. Background Technology
[0002] Plastic products are prone to "stress whitening" when bent, especially dark-colored products. When plastic is bent, the outer side of the bend is subjected to tensile stress. The force first straightens the molecular chains. If the stress is large enough, the molecular chains will be pulled apart, creating nanoscale or microscale microcracks or cavities. The size of these cavities is close to the wavelength of light, causing diffuse reflection of light, which appears white to the human eye.
[0003] Current improvement methods include reducing the use of fillers and toughening agents, and lowering the holding pressure. However, it is easy to understand that all of these methods will lead to a decrease in the mechanical strength of plastic products.
[0004] There is an urgent need for a method to improve the resistance of color masterbatch to "stress whitening" without relying on reducing fillers / toughening agents / holding pressure. Summary of the Invention
[0005] To address the shortcomings of existing technologies, one objective of this invention is to provide a PVC masterbatch with high bending and weather resistance; another objective is to provide a method for preparing a PVC masterbatch with high bending and weather resistance; and a third objective is to provide a method for using a PVC masterbatch with high bending and weather resistance.
[0006] One of the objectives of this invention is achieved through the following technical solution: A PVC color masterbatch with high bending resistance and weather resistance is prepared from the following raw materials in parts by weight: The composition includes 40 parts carrier resin, 22 parts pigment, 12 parts polyester plasticizer, 5 parts epoxidized soybean oil, 2 parts thermally expandable microspheres, and 9 parts processing aids. The thermally expandable microspheres are microcapsules with a core-shell structure; the core is a low-boiling-point hydrocarbon foaming agent, and the outer shell is a thermoplastic polymer. When heated, the core vaporizes, generating pressure, while the outer shell softens and expands, increasing its volume. The principle behind its "stress whitening" effect during bending is that reversible deformation occurs during bending, consuming strain energy and preventing the formation of new cavities.
[0007] Furthermore, the carrier resin is obtained by mixing PVC resin (k=75) and chlorinated polyethylene in a weight ratio of 3:1. The role of chlorinated polyethylene is to toughen the material and reduce the modulus difference in the bending zone.
[0008] Furthermore, the pigment is obtained by mixing high-pigment carbon black (20nm), titanium dioxide (R type), and phthalocyanine blue in a weight ratio of 6:4:1.
[0009] Furthermore, the method for preparing the thermally expandable microspheres includes: Step 1: Weigh the aqueous phase raw materials and oil phase raw materials according to their weight proportions. The aqueous phase raw materials include 100 parts deionized water, 5 parts nano silica, 0.5 parts PVP dispersant, 10 parts sodium chloride, and 0.1 parts sodium nitrite. The oil phase raw materials include 20 parts acrylonitrile, 10 parts methyl methacrylate, 15 parts vinylidene chloride, 0.5 parts EGDMA crosslinking agent, 0.5 parts AIBN initiator, and 8 parts isooctane. Step 2: Mix the aqueous raw materials and then ultrasonically disperse them for 15-30 minutes to obtain the aqueous phase; Step 3: Mix all raw materials except isooctane evenly in the oil phase, then add isooctane to obtain the oil phase. Isooctane is a foaming agent and must be added last, otherwise it will easily evaporate. Step 4: Introduce the oil phase into the aqueous phase and emulsify at 5000-10000 rpm for 5-15 min to obtain a suspension emulsion; Step 5: The suspension emulsion is reacted at 60-70℃ and 0.5-1.0MPa for 15-20h under nitrogen atmosphere protection, and then the temperature is raised to 90-110℃ and the pressure is maintained for 2-4h. Step 6: After cooling to room temperature, release the pressure and filter to obtain thermally expanded microspheres.
[0010] Furthermore, step six also includes washing the thermally expanded microspheres with deionized water 3-5 times. This is to prevent soluble substances in the aqueous raw materials from affecting the color masterbatch processing.
[0011] Furthermore, step six also includes placing the thermally expanded microspheres in a 50-60°C environment and vacuum drying for 24 hours to prevent moisture from affecting the color masterbatch processing.
[0012] The second objective of this invention is achieved through the following technical solution: A method for preparing a PVC color masterbatch with high flexural strength and weather resistance includes the following steps: S1, Weigh the raw materials; S2, premix the raw materials at a temperature of 50-80℃ to prevent the thermal expansion microspheres from foaming prematurely. S3 involves mixing and extruding the raw materials at 150-165℃ and then ring-cutting them into pellets using a water ring, maintaining the thermal expansion microsphere state through low-temperature granulation. S4. Dry the granules at 60-70℃ for 2-4 hours to obtain PVC masterbatch with high bending resistance and weather resistance.
[0013] Furthermore, the premixing speed in S2 is 600-700 rpm. If the speed is too high, the powder may experience localized high temperatures, which could lead to premature foaming of the thermally expanding microspheres.
[0014] The third objective of this invention is achieved through the following technical solution: A method for using a PVC color masterbatch with high bending resistance and weather resistance includes: The PVC bend-resistant and weather-resistant masterbatch is mixed with PVC resin at a weight ratio of 2-5:95 and then injection molded.
[0015] Furthermore, during the injection molding process, the feeding section is set at 160-170℃, the compression section at 170-180℃, the nozzle section at 180-190℃, the mold temperature at 60℃, the injection pressure at 60MPa, and the holding pressure at 40% of the injection pressure. This provides high safety, preventing the PVC from overheating and generating corrosive gases. Additionally, this temperature can stimulate the expansion of the thermally expanding microspheres, thereby forming cavities inside the microspheres to absorb bending stress. These cavities can recover after the stress disappears.
[0016] The beneficial effects of this invention are as follows: This invention uses thermally expandable microspheres as the core structure of the color masterbatch to resist stress whitening. This method does not depend on the modification of the substrate, so it does not affect the subsequent bonding of the color masterbatch with PVC resin. In addition, the ability to resist stress whitening is further enhanced by the optical masking of pigments and the mechanical improvement of toughening agents. Detailed Implementation
[0017] The following is a further explanation with reference to specific implementation methods: Color masterbatch formula (by weight) Overall formulation of color masterbatch: carrier resin 40, pigment 22, polyester plasticizer 12, epoxidized soybean oil 5, thermal expansion microspheres 2, processing aids 9; Carrier resin: 30 parts PVC resin (k=75) + 10 parts chlorinated polyethylene (ratio 3:1); Pigment: 12 parts of 20nm high pigment carbon black + 8 parts of R-type titanium dioxide + 2 parts of phthalocyanine blue (ratio 6:4:1).
[0018] Thermally expandable microsphere formulation (parts by weight) Aqueous phase raw materials: 100g deionized water, 5g nano silica, 0.5g PVP dispersant, 10g sodium chloride, 0.1g sodium nitrite; Oil phase raw materials: Acrylonitrile 20, Methyl methacrylate 10, Vinylidene chloride 15, EGDMA crosslinking agent 0.5, AIBN initiator 0.5, Isooctane 8. Example 1
[0019] I. Preparation of Thermally Expanding Microspheres Mix the aqueous raw materials and ultrasonically disperse for 15 minutes; The oil phase was mixed thoroughly except for isooctane. Finally, isooctane was added, and the oil phase was added to the aqueous phase. The mixture was emulsified at 5000 rpm for 5 min to obtain a suspension emulsion. Under nitrogen protection, the reaction was carried out at 60℃ and 0.5MPa for 15 hours; then the temperature was raised to 90℃ and held at the pressure for 2 hours. Cool and depressurize, filter, and wash three times with deionized water; Thermally expanded microspheres were obtained by vacuum drying at 50℃ for 24 hours.
[0020] II. Preparation of PVC Masterbatch S1: Weigh all raw materials according to the general formula; S2: Premixing temperature 50℃, rotation speed 600rpm, to complete raw material premixing; S3: Internal mixing and extrusion at 150℃, followed by water ring pelletizing; S4: The granules are dried at 60℃ for 2 hours to obtain the finished color masterbatch.
[0021] III. Mixing and Injection Molding Applications Mixing: Masterbatch: PVC resin (k=75, the same below) = 2:95 (by weight); Injection molding process: feeding section 160℃, compression section 170℃, nozzle section 180℃; Fixed parameters: mold temperature 60℃, injection pressure 60MPa, holding pressure 24MPa; injection molding completed. Example 2
[0022] I. Preparation of Thermally Expanding Microspheres Aqueous raw materials were mixed and ultrasonically dispersed for 22 minutes. Finally, isooctane was added to the oil phase, and after mixing with the aqueous phase, it was emulsified at 7500 rpm for 10 min to obtain a suspension emulsion. Under nitrogen protection, the reaction was carried out at 65℃ and 0.75MPa for 17.5h; then the temperature was raised to 100℃ and held at the pressure for 3h. Cool and depressurize, filter, and wash with deionized water 4 times; Thermally expanded microspheres were obtained by vacuum drying at 55℃ for 24 hours.
[0023] II. Preparation of PVC Masterbatch S1: Weigh all raw materials according to the general formula; S2: Premixing temperature 65℃, rotation speed 650rpm, to complete raw material premixing; S3: Internal mixing and extrusion at 157.5℃, followed by water ring pelletizing; S4: The granules are dried at 65℃ for 3 hours to obtain the finished color masterbatch.
[0024] III. Mixing and Injection Molding Applications Mixing ratio: Masterbatch: PVC resin = 3.5:95 (by weight); Injection molding process: feeding section 165℃, compression section 175℃, nozzle section 185℃; Fixed parameters: mold temperature 60℃, injection pressure 60MPa, holding pressure 24MPa; injection molding completed. Example 3
[0025] I. Preparation of Thermally Expanding Microspheres Mix the aqueous raw materials and ultrasonically disperse for 30 minutes; Finally, isooctane was added to the oil phase, and after mixing with the aqueous phase, it was emulsified at 10,000 rpm for 15 min to obtain a suspension emulsion. Under nitrogen protection, the reaction was carried out at 70℃ and 1.0MPa for 20 hours; then the temperature was raised to 110℃ and held at the pressure for 4 hours. Cool and depressurize, filter, and wash with deionized water 5 times; Thermally expanded microspheres were obtained by vacuum drying at 60℃ for 24 hours.
[0026] II. Preparation of PVC Masterbatch S1: Weigh all raw materials according to the general formula; S2: Premixing temperature 80℃, rotation speed 700rpm, to complete raw material premixing; S3: Internal mixing and extrusion at 165℃, followed by water ring pelletizing; S4: The granules are dried at 70℃ for 4 hours to obtain the finished color masterbatch.
[0027] III. Mixing and Injection Molding Applications Mixing ratio: Masterbatch: PVC resin = 5:95 (by weight); Injection molding process: feeding section 170℃, compression section 180℃, nozzle section 190℃; Fixed parameters: mold temperature 60℃, injection pressure 60MPa, holding pressure 24MPa; injection molding completed.
[0028] Comparative Example 1 The only difference from Example 2 is that the thermally expanded microspheres are replaced with foamed microspheres of equal weight (HY-180D, purchased from Shenzhen Heyan Yuese Plastic Pigment Additives Co., Ltd., with an initiation temperature of 150°C and a maximum foaming temperature of 190°C).
[0029] Comparative Example 2 The only difference from Example 2 is that the thermally expandable microspheres are replaced with an equal weight of 3M XLD3000 hollow glass beads (purchased from 3M).
[0030] Color difference test: The tubular plastic parts (outer diameter 1 cm, inner diameter 0.75 cm, length 5 cm) prepared in Examples 1, 2, 3, Comparative Example 1, and Comparative Example 2 were bent at 45° and immediately flattened. The color difference ΔE was measured using a colorimeter. The color difference ΔE was measured again using a colorimeter 24 hours later. Each experiment was repeated 9 times and the average value was taken. The results are shown in Table 1.
[0031] Table 1 Color Difference Test
[0032] As shown in Table 1, the whitening of the plastic parts obtained by this invention after bending is very slight and barely noticeable to the naked eye (ΔE < 1), and there is almost no rebound even after 24 hours. In contrast, Comparative Example 1, which uses a similar technique, shows slightly more severe whitening (ΔE 1.9, identifiable to the naked eye but not obvious), and exhibits some rebound (ΔE increases significantly after 24 hours). Comparative Example 2, which uses hollow glass beads, shows very obvious whitening.
[0033] The embodiments and descriptions above are merely illustrative of the principles and preferred embodiments of the present invention. Various changes and modifications may be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.
Claims
1. A PVC color masterbatch with high bending resistance and weather resistance, characterized in that, It is prepared from the following raw materials in parts by weight: The mixture contains 40 parts carrier resin, 22 parts pigment, 12 parts polyester plasticizer, 5 parts epoxidized soybean oil, 2 parts thermally expanded microspheres, and 9 parts processing aids.
2. The PVC masterbatch with high bending resistance and weather resistance according to claim 1, characterized in that: The carrier resin is obtained by mixing PVC resin and chlorinated polyethylene in a weight ratio of 3:
1.
3. The PVC masterbatch with high bending resistance and weather resistance according to claim 1, characterized in that: The pigment is obtained by mixing high-pigment carbon black, titanium dioxide and phthalocyanine blue in a weight ratio of 6:4:
1.
4. The PVC masterbatch with high bending resistance and weather resistance according to claim 1, characterized in that: The method for preparing the thermally expandable microspheres includes: Step 1: Weigh the aqueous phase raw materials and oil phase raw materials according to their weight proportions. The aqueous phase raw materials include 100 parts deionized water, 5 parts nano silica, 0.5 parts PVP dispersant, 10 parts sodium chloride, and 0.1 parts sodium nitrite. The oil phase raw materials include 20 parts acrylonitrile, 10 parts methyl methacrylate, 15 parts vinylidene chloride, 0.5 parts EGDMA crosslinking agent, 0.5 parts AIBN initiator, and 8 parts isooctane. Step 2: Mix the aqueous raw materials and then ultrasonically disperse them for 15-30 minutes to obtain the aqueous phase; Step 3: Mix all raw materials except isooctane in the oil phase until homogeneous, then add isooctane to obtain the oil phase; Step 4: Introduce the oil phase into the aqueous phase and emulsify at 5000-10000 rpm for 5-15 min to obtain a suspension emulsion; Step 5: The suspension emulsion is reacted at 60-70℃ and 0.5-1.0MPa for 15-20h under nitrogen atmosphere protection, and then the temperature is raised to 90-110℃ and the pressure is maintained for 2-4h. Step 6: After cooling to room temperature, release the pressure and filter to obtain thermally expanded microspheres.
5. The PVC masterbatch with high bending resistance and weather resistance according to claim 4, characterized in that: Step six also includes washing the thermally expanded microspheres with deionized water 3-5 times.
6. The PVC masterbatch with high bending resistance and weather resistance according to claim 4, characterized in that: Step six also includes placing the thermally expanded microspheres in a 50-60℃ environment and vacuum drying for 24 hours.
7. A method for preparing a PVC masterbatch with high flexural strength and weather resistance as described in claim 1, characterized in that, Includes the following steps: S1, Weigh the raw materials; S2, premix the raw materials at a temperature of 50-80℃ to prevent the thermal expansion microspheres from foaming prematurely. S3 involves mixing and extruding the raw materials at 150-165℃ and then ring-cutting them into pellets using a water ring, maintaining the thermal expansion microsphere state through low-temperature granulation. S4. Dry the granules at 60-70℃ for 2-4 hours to obtain PVC masterbatch with high bending resistance and weather resistance.
8. The preparation method according to claim 7, characterized in that: The premixing speed in S2 is 600-700 rpm.
9. A method of using the PVC flexural strength and weather resistance masterbatch as described in claim 1, characterized in that, The PVC bend-resistant and weather-resistant masterbatch is mixed with PVC resin at a weight ratio of 2-5:95 and then injection molded.
10. The method of use according to claim 9, characterized in that: During the injection molding process, the feeding section is set at 160-170℃, the compression section at 170-180℃, the nozzle section at 180-190℃, the mold temperature at 60℃, the injection pressure at 60MPa, and the holding pressure at 40% of the injection pressure.