High-mechanical-property high-flowability shoe material foaming PVC resin and preparation method and application thereof

Abstract

The application provides a high-mechanical-property high-flowability shoe material foaming PVC resin and a preparation method and application thereof, and belongs to the technical field of shoe material foaming materials. The high-mechanical-property high-flowability shoe material foaming PVC resin is prepared through polymerization of raw materials including a vinyl chloride monomer, a second monomer, a third monomer, a dispersing agent, an initiator, a stabilizer, a terminator and a defoaming agent. The second monomer and the third monomer are used for copolymerization modification of the PVC resin in specific types and specific proportions, and the polymerization temperature is strictly controlled to control the polymerization degree of the copolymerization product, so that the copolymerization product has high mechanical properties, high melt flowability and good heat resistance, and has a good application prospect in the field of shoe material foaming processing and the like.

Description

Technical Field

[0001] This invention relates to the field of shoe material foaming technology, specifically to a high-mechanical-performance, high-flowability shoe material foaming PVC resin, its preparation method, and its application. Background Technology

[0002] PVC foam shoe material is a lightweight, wear-resistant, and adjustable-hardness and color sole material widely used in athletic and casual shoes. Due to the requirement for high wear resistance, tensile strength, and other mechanical properties, current shoe material foaming primarily uses SG3 type PVC resin with a high degree of polymerization, or a combination of high-polymerization resin and general-purpose resin. However, high-polymerization PVC resin has poor processing performance and insufficient melt flow, making it difficult to process, especially in injection-molded shoe material foaming applications, where processing is even more challenging.

[0003] Therefore, developing a PVC resin that has both high mechanical properties and high fluidity is of great practical significance in the field of shoe material foaming.

[0004] Previously, the applicant proposed a high-polymerization-degree PVC resin for foaming and injection molding in patent CN118459645A. This involved introducing a copolymer soft monomer into the polymerization reaction system to enable the high-polymerization-degree PVC material to foam and be injection molded normally. However, it did not address how to improve the insufficient thermal stability of the PVC resin. Therefore, this invention provides a high-mechanical-performance, high-flowability foamed PVC resin for footwear materials, its preparation method, and its applications. By using specific monomers to copolymerize and modify the PVC resin, the problem of insufficient thermal stability of the PVC resin is significantly improved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-mechanical-performance, high-flowability PVC resin for shoe material foaming, its preparation method, and its applications. By using specific types and proportions of second and third monomers to copolymerize and modify the PVC resin, and by strictly controlling the polymerization temperature to control the degree of polymerization of the copolymer, the copolymer possesses high mechanical properties, high melt flowability, and good heat resistance, showing promising application prospects in shoe material foaming processing and other fields.

[0006] To achieve the above objectives, the specific technical solution of the present invention is as follows:

[0007] In a first aspect, the present invention provides a high mechanical property and high flowability foamed PVC resin for shoe materials, which is made by polymerization reaction of raw materials including vinyl chloride monomer, second monomer, third monomer, dispersant, initiator, stabilizer, terminator and defoamer;

[0008] The second monomer is selected from at least one of butyl acrylate, methyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, vinyl lauryl ester, vinyl octyl ether acetate, vinyl isobutyl ether, vinyl ethyl ether, vinyl n-butyl ether, vinyl octadecyl ether, cetyl vinyl ether, vinyl acetate, hydroxyethyl methacrylate, and hydroxyethyl vinyl ether.

[0009] The third monomer is selected from at least one of 4-aminostyrene, 4-(dimethylamino)styrene, N-(2-aminoethyl)acrylamide, N-(2-(2-aminoethyl)amino)ethyl)acrylamide (AECAm), dimethylaminoethyl methacrylate (DMAEMA), and tert-butylaminoethyl methacrylate (TBAEMA).

[0010] In existing technologies, for foamed shoe materials requiring high mechanical properties, high-polymerization-degree PVC resins, such as SG3, are generally selected during injection molding to ensure good mechanical properties. However, high-polymerization-degree PVC resins have insufficient melt flowability, leading to extrusion difficulties during injection molding and hindering production. Therefore, this invention provides a high-mechanical-performance, high-flowability foamed PVC resin for shoe materials to solve the above-mentioned process problems. This invention uses specific second and third monomers to copolymerize and modify PVC resin, and simultaneously controls the polymerization temperature to precisely control the degree of polymerization of the copolymerized PVC resin. This results in the copolymerized PVC resin possessing both high mechanical properties and excellent flowability and heat resistance, making it easier to inject mold and solving the problem in existing technologies where high-polymerization-degree PVC resins are difficult to combine easy injection molding with good heat resistance. The introduction of the second monomer significantly enhances the internal plasticizing effect of PVC resin, disrupts the regularity of PVC molecular chains, weakens the cohesive force of PVC molecular chains, reduces melt viscosity, and improves fluidity. When the second monomer contains long, flexible aliphatic side chains, it can also provide internal lubrication, such as vinyl laurate and vinyl octyl ether. The third monomer contains amino groups (e.g., tertiary, secondary, and primary amines), which can react rapidly with the hydrogen chloride (HCl) gas released from PVC resin to generate stable ammonium salts, greatly reducing the catalytic effect of HCl on the decomposition of PVC resin and significantly improving the thermal stability of PVC resin.

[0011] Introducing only a second monomer can improve the flow properties of PVC resin to some extent. However, after the second monomer copolymerizes into the PVC molecular chain, the copolymer product contains ester / ether groups introduced by the second monomer, which significantly reduces the thermal stability of the PVC resin. For example, with vinyl acetate monomer, after vinyl acetate copolymerizes into the molecular chain, its own ester group structure becomes a new and more fragile link, greatly reducing the thermal stability of the PVC resin. Upon heating, the PVC resin releases HCl gas, which acts as a catalyst for further Cl- removal, exacerbating the decomposition of the PVC resin. Therefore, this invention, in addition to introducing a second monomer, further introduces a third monomer to improve the thermal stability of the PVC resin. For example, dimethylaminoethyl methacrylate (DMCA), after the third monomer copolymerizes into the molecular chain, can quickly absorb the HCl gas released by the PVC resin and react to form a stable ammonium salt, greatly improving the heat resistance of the PVC resin.

[0012] Further, the amount of the second monomer is 2.5% to 7.5% of the total monomer mass; the amount of the third monomer is 0.1% to 1.0% of the total monomer mass. The total monomer mass mentioned in this invention refers to the sum of the masses of the vinyl chloride monomer, the second monomer, and the third monomer.

[0013] Further, the dispersant includes a primary dispersant 1, a primary dispersant 2, and a co-dispersant, wherein the amount of the dispersant is 500-1500 ppm of the total monomer mass; wherein, the primary dispersant 1 is polyvinyl alcohol (PVA) with a degree of hydrolysis in the range of 70-90 mol%, and the amount of the primary dispersant 1 is 400-750 ppm of the total monomer mass; the primary dispersant 2 is selected from at least one of methylcellulose (MC), hydroxymethylcellulose (CMC), hydroxyethylcellulose (HEC), and hydroxypropyl methylcellulose (HPMC), and the amount of the primary dispersant 2 is 50-500 ppm of the total monomer mass; the co-dispersant is polyvinyl alcohol with a degree of hydrolysis in the range of 45-55 mol%, and the amount of the co-dispersant is 50-250 ppm of the total monomer mass.

[0014] Furthermore, the initiator is selected from at least one of tert-butyl peroxyneodecanate, cumyl peroxyneodecanate, di(3,3,5-trimethylhexanoyl)peroxide, and bis(2-ethylhexyl) peroxydicarbonate, and the amount of the initiator is 200-1000 ppm of the total mass of the monomer.

[0015] Furthermore, the stabilizer is selected from at least one of ammonia, sodium carbonate, and sodium bicarbonate, and the amount of the stabilizer used is 100-500 ppm of the total mass of the monomers.

[0016] Furthermore, the terminator is selected from at least one of bisphenol A, acetone thiourea, α-methylstyrene, and nonylphenol, and the amount of the terminator is 200-800 ppm of the total mass of the monomers.

[0017] Furthermore, the defoamer is selected from at least one of polysiloxane, organic modified polysiloxane, and polyether modified organosilicon, and the amount of the defoamer is 100-500 ppm of the total mass of the monomers.

[0018] Furthermore, the polymerization reaction is carried out at a temperature of 48~52 °C.

[0019] Secondly, the present invention provides a method for preparing the high-mechanical-performance, high-flowability foamed PVC resin for footwear materials, comprising the following steps:

[0020] Dispersant, stabilizer, water, and initiator are added to the reactor. After a protective gas is introduced, vinyl chloride monomer, second monomer, and third monomer are added, and polymerization is carried out at 48-52 °C. During the reaction, water is continuously added as the volume of the remaining reactants decreases. When the pressure drops by 1 bar, a terminator and defoamer are added to obtain high-mechanical-performance, high-flowability foamed PVC resin for shoe materials.

[0021] Thirdly, the present invention provides the application of the high mechanical properties and high fluidity PVC resin for shoe material foaming in the fields of shoe material foaming processing, pipe processing, film processing or wire and cable processing.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] This invention involves polymerizing specific types and proportions of second and third monomers with vinyl chloride monomer to prepare a copolymerized PVC resin that possesses high mechanical properties, excellent flowability, and heat resistance. This copolymerized PVC resin shows promising application prospects in fields such as shoe material foaming. Detailed Implementation

[0024] To enable those skilled in the art to clearly and completely understand the technical solution of the present invention, the present invention will be further described in detail below with reference to embodiments. Obviously, the embodiments described herein are only for explaining the present invention and are not intended to limit the scope of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in this invention are conventional reagents, methods and equipment in the art.

[0026] This invention provides a high-mechanical-performance, high-flowability foamed PVC resin for shoe materials, which is made by polymerization reaction of raw materials including vinyl chloride monomer, second monomer, third monomer, dispersant, initiator, stabilizer, terminator and defoamer;

[0027] The second monomer is selected from at least one of butyl acrylate, methyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, vinyl lauryl ester, vinyl octyl ether acetate, vinyl isobutyl ether, vinyl ethyl ether, vinyl n-butyl ether, vinyl octadecyl ether, cetyl vinyl ether, vinyl acetate, hydroxyethyl methacrylate, and hydroxyethyl vinyl ether.

[0028] The third monomer is selected from at least one of 4-aminostyrene, 4-(dimethylamino)styrene, N-(2-aminoethyl)acrylamide, N-(2-(2-aminoethyl)amino)ethyl)acrylamide (AECAm), dimethylaminoethyl methacrylate (DMAEMA), and tert-butylaminoethyl methacrylate (TBAEMA).

[0029] In some examples, the amount of the second monomer is 2.5% to 7.5% of the total monomer mass; the amount of the third monomer is 0.1% to 1.0% of the total monomer mass. The total monomer mass referred to in this invention means the sum of the masses of the vinyl chloride monomer, the second monomer, and the third monomer.

[0030] In some examples, the dispersant includes a primary dispersant 1, a primary dispersant 2, and a co-dispersant, used in amounts of 500-1500 ppm of the total monomer mass; wherein, the primary dispersant 1 is polyvinyl alcohol (PVA) with a degree of hydrolysis in the range of 70-90 mol%, used in amounts of 400-750 ppm of the total monomer mass; the primary dispersant 2 is selected from at least one of methylcellulose (MC), hydroxymethylcellulose (CMC), hydroxyethylcellulose (HEC), and hydroxypropyl methylcellulose (HPMC), used in amounts of 50-500 ppm of the total monomer mass; and the co-dispersant is polyvinyl alcohol with a degree of hydrolysis in the range of 45-55 mol%, used in amounts of 50-250 ppm of the total monomer mass.

[0031] In some examples, the initiator is selected from at least one of tert-butyl peroxyneodecanate, cumyl peroxyneodecanate, di(3,3,5-trimethylhexanoyl)peroxide, and bis(2-ethylhexyl) peroxydicarbonate, and is used in an amount of 200 to 1000 ppm of the total monomer mass.

[0032] In some examples, the stabilizer is selected from at least one of ammonia, sodium carbonate, and sodium bicarbonate, and is used in an amount of 100 to 500 ppm of the total mass of the monomer.

[0033] In some examples, the terminator is selected from at least one of bisphenol A, acetone thiourea, α-methylstyrene, and nonylphenol, and is used in an amount of 200 to 800 ppm of the total mass of the monomers.

[0034] In some examples, the defoamer is selected from at least one of polysiloxane, organic modified polysiloxane, and polyether modified organosilicon, and is used in an amount of 100 to 500 ppm of the total mass of the monomers.

[0035] In some examples, the polymerization reaction is carried out at a temperature of 48–52 °C.

[0036] Example 1

[0037] This embodiment describes a high-mechanical-performance, high-flowability foamed PVC resin for shoe materials. The preparation steps are as follows:

[0038] S1. Clean the reactor and add the prepared dispersant into the reactor; the dispersant includes main dispersant 1, main dispersant 2, and co-dispersant; wherein, the main dispersant 1 is a PVA solution with a degree of alcoholysis of 72 mol%, the concentration of the PVA solution is 1.0%, and the amount of PVA solution used is 550 g; the main dispersant 2 is an HPMC solution with a concentration of 1.0%, and the amount of HPMC solution used is 275 g; the co-dispersant is a PVA solution with a degree of alcoholysis of 55 mol%, the concentration of the PVA solution is 40.0%, and the amount of PVA solution used is 2.50 g.

[0039] S2. Add 2.50 g of sodium bicarbonate stabilizer to the reaction vessel.

[0040] S3. Add 12,000 g of pure water to the reactor.

[0041] S4. Add the initiator to the reaction vessel; the initiator includes initiator 1 and initiator 2; wherein, initiator 1 is tert-butyl peroxyneodecanate, with an amount of 4.5 g, and initiator 2 is cumyl peroxyneodecanate, with an amount of 4.5 g.

[0042] S5. Introduce nitrogen to replace the air in the reactor. Repeat the nitrogen replacement four times. Turn on the stirrer and add vinyl chloride monomer (9450 g), butyl acrylate (500 g), and 4-aminostyrene (50 g).

[0043] S6. Heat to 50 ℃ to start the reaction. During the reaction, the volume of the remaining reactants decreases due to the sedimentation of the copolymer. Water needs to be added continuously as the volume of the remaining reactants decreases during polymerization.

[0044] S7. After the pressure drop is 1 bar, add 8 g of bisphenol A as a terminator; add 2.5 g of polysiloxane as an antifoaming agent, stir for 10 min, and then cool down and discharge the material.

[0045] S8. Dry the material at 65 ℃ for 48 h to obtain high mechanical properties and high flowability foamed PVC resin for shoe materials.

[0046] Comparative Example 1

[0047] The preparation steps of PVC resin in Comparative Example 1 are basically the same as those in Example 1, except that an equal amount of the third monomer is used to replace the second monomer in Comparative Example 1. That is, step S5 of preparing PVC resin in Comparative Example 1 is as follows: nitrogen gas is introduced to replace the air in the reactor. The nitrogen gas is replaced 4 times. Stirring is turned on, and vinyl chloride monomer is added in an amount of 9450 g. 4-Aminostyrene is added in an amount of 550 g.

[0048] Comparative Example 2

[0049] The preparation steps of PVC resin in Comparative Example 2 are basically the same as those in Example 1, except that an equal amount of the second monomer is used to replace the third monomer in Comparative Example 2. That is, step S5 of preparing PVC resin in Comparative Example 2 is as follows: nitrogen gas is introduced to replace the air in the reactor. The nitrogen gas is replaced 4 times. Stirring is turned on, and vinyl chloride monomer is added in an amount of 9450 g. Butyl acrylate is added in an amount of 550 g.

[0050] The PVC resins prepared in Example 1 and Comparative Examples 1-2 were tested for melt flowability (melt index), thermal stability, mechanical properties, degree of polymerization, and foaming properties, and compared with general-purpose PVC resins (types: SG3, SG8). Specific test methods are as follows:

[0051] Melt flowability test (melt index): 100 parts by weight of PVC resin, 95 parts by weight of DOP plasticizer, 5.5 parts by weight of calcium-zinc stabilizer and 100 parts by weight of calcium carbonate were mixed and stirred evenly. The mixture was then kneaded for 5 min at 160 ℃ and 35 rpm using a rheometer. The resulting plasticized material was used to test the melt flowability. The test conditions were 160 ℃ / 2.16 kg, and the test was conducted according to the method of GB / T2951.41-2008.

[0052] Thermal stability test: 100 parts by weight of PVC resin, 95 parts by weight of DOP plasticizer, 5.5 parts by weight of calcium-zinc stabilizer, and 100 parts by weight of calcium carbonate were mixed and stirred evenly. The mixture was then subjected to intensive mixing at 160 ℃ and 35 rpm for 5 min using a rheometer. The resulting plasticized material was used to test its thermal stability. The decomposition time was tested using a rheometer with the following parameters: temperature 185 ℃ and rotation speed 35 rpm.

[0053] Mechanical property testing: 100 parts by weight of PVC resin, 1.5 parts by weight of organotin stabilizer, 0.65 parts by weight of stearic acid lubricant, and 26 parts by weight of DOP plasticizer were mixed and stirred evenly. The mixture was then milled on a two-roll mill at 175 ℃ for 5 min. Following this, it was molded using a flat vulcanizing apparatus at 180 ℃ for 3 min, with a molding thickness of 1 mm. The molded samples were cut and their tensile properties were tested according to the method in GB / T 1040.2-2006.

[0054] Degree of polymerization test: The test shall be conducted in accordance with the method in Appendix A of GB / T 5761-2018.

[0055] Footwear material foaming and performance testing: 100 parts by weight of PVC resin, 4 parts by weight of calcium-zinc stabilizer, 60 parts by weight of DOTP plasticizer, 4 parts by weight of ACR toughening agent, and 1.5 parts by weight of AC foaming agent were mixed evenly and then extruded and granulated using a twin-screw extruder. The extruder temperatures were: heating stage 1: 160 ℃, heating stage 2: 165 ℃, heating stage 3: 170 ℃, heating stage 4: 175 ℃, and die temperature: 175 ℃. The extruder and die temperatures must be lower than the decomposition temperature of the AC foaming agent (195~220 ℃). The resulting granules were then injection molded and foamed. The finished product obtained from the injection molding was tested for tensile strength and elongation at break according to GB / T 1040.2-2006, and for tear strength according to GB / T 529-2008. The injection molding conditions are as follows:

[0056]

[0057] The melt flowability, thermal stability, mechanical properties, degree of polymerization, and foaming performance test results of the PVC resins prepared in Examples 1 and Comparative Examples 1-2, and general-purpose PVC resins (models: SG3, SG8) are shown in Table 1.

[0058] Table 1: Test results of the properties of PVC resin and foamed injection molded products in Examples 1 and 1-2

[0059]

[0060] As can be seen from the test data in Table 1, the performance of the PVC resin prepared in Example 1 of this invention, as well as its foaming performance for shoe materials, exceeds that of commonly used SG3 and SG8 type PVC resins; at the same time, its melt index exceeds that of SG8 type PVC resin, classifying it as a high-mechanical-performance, high-flow-rate PVC resin. In this invention, resins with higher flow rates than SG8 type are considered high-flow-rate resins, and resins with higher mechanical properties than SG3 type are considered high-mechanical-performance resins.

[0061] Compared to Example 1, Comparative Example 1 used an equal amount of the third monomer to replace the second monomer, meaning that Comparative Example 1 only used the third monomer to copolymerize and modify the PVC resin. The melt index of the resulting PVC resin was significantly lower than that of SG3 type PVC resin, requiring an increase in injection pressure of 30 bar during injection molding. After the pressure was increased, the foamed injection molded products showed yellowing due to high-pressure shear. Comparative Example 2 used an equal amount of the second monomer to replace the third monomer, meaning that Comparative Example 2 only used the second monomer to copolymerize and modify the PVC resin. The thermal decomposition time of the resulting PVC resin was significantly reduced, resulting in insufficient thermal stability and causing slight yellowing in the foamed injection molded products.

[0062] Example 2

[0063] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 2 is basically the same as that in Example 1, except that the polymerization reaction temperature in Example 2 is 48 ℃. Specifically, step S6 of Example 2 is as follows: the temperature is raised to 48 ℃ to begin the reaction. During the reaction, due to the sedimentation of the copolymer, the volume of the remaining reactants decreases, requiring continuous replenishment of water as the volume of the remaining reactants decreases during polymerization.

[0064] Example 3

[0065] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 3 is basically the same as that in Example 1, except that the polymerization temperature in Example 3 is 52 ℃. Specifically, step S6 in Example 3 is as follows: the temperature is raised to 52 ℃ to begin the reaction. During the reaction, due to the sedimentation of the copolymer, the volume of the remaining reactants decreases, requiring continuous replenishment of water as the volume of the remaining reactants decreases during polymerization.

[0066] The melt flowability, thermal stability, mechanical properties, degree of polymerization, and foaming properties of the PVC resins in Examples 1-3 are shown in Table 2, and are compared with those of general PVC resins.

[0067] Table 2: Test results of the properties of PVC resin and foamed injection molded products in Examples 1-3

[0068]

[0069] As can be seen from the test data in Table 2, the mechanical properties of PVC resin and its foamed products decrease with increasing polymerization temperature. When the polymerization temperature is 52 °C, the tensile strength of PVC resin and its foamed products is comparable to that of SG3 type PVC resin. To ensure high mechanical properties of PVC resin and its foamed products, the polymerization temperature cannot be further increased. Therefore, this invention limits the maximum polymerization temperature to 52 °C.

[0070] As the polymerization temperature decreases, the melt index and fluidity of PVC resin decrease. When the polymerization temperature is 48 °C, the melt index of PVC resin is the same as that of SG8 type PVC resin. To ensure that the PVC resin has high fluidity, the polymerization temperature cannot be lowered further. Therefore, this invention limits the minimum polymerization temperature to 48 °C.

[0071] Example 4

[0072] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 4 is basically the same as that in Example 1, except that the amount of the second monomer used in Example 4 is different. Specifically, step S5 of Example 4 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9700 g) is added; butyl acrylate (250 g) is added; and 4-aminostyrene (50 g) is added.

[0073] Example 5

[0074] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 5 is basically the same as that in Example 1, except that the amount of the second monomer used in Example 5 is different. Specifically, step S5 of Example 5 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9200 g) is added; butyl acrylate (750 g) is added; and 4-aminostyrene (50 g) is added.

[0075] The test results of melt flowability, thermal stability, mechanical properties, degree of polymerization and foaming properties of the PVC resins in Examples 1 and 4-5 are shown in Table 3, and are compared with those of general PVC resins.

[0076] Table 3: Test results of the properties of PVC resin and foamed injection molded products in Examples 1 and 4-5

[0077]

[0078] As can be seen from the test data in Table 3, as the amount of the second monomer increases, the fluidity of the PVC resin increases, but at the same time the mechanical strength and thermal decomposition time decrease. When the content of the second monomer is reduced to 7.5%, the thermal decomposition time of the PVC resin decreases to 1356 s. In order to ensure that the PVC resin has good thermal stability, the present invention limits the maximum content of the second monomer to 7.5%.

[0079] As the amount of the second monomer decreases, the fluidity of the PVC resin decreases; when the content of the second monomer decreases to 2.5%, the fluidity of the PVC resin is the same as that of SG8 type PVC resin; in order to ensure that the PVC resin has good fluidity, the present invention limits the minimum content of the second monomer to 2.5%.

[0080] Example 6

[0081] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 6 is basically the same as that in Example 1, except that the amount of the third monomer used in Example 6 is different. Specifically, step S5 of Example 6 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9490 g) is added; butyl acrylate (500 g) is added; and 4-aminostyrene (10 g) is added.

[0082] Example 7

[0083] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 7 is basically the same as that in Example 1, except that the amount of the third monomer used in Example 7 is different. Specifically, step S5 of Example 7 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9425 g) is added; butyl acrylate (500 g) is added; and 4-aminostyrene (75 g) is added.

[0084] Example 8

[0085] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 8 is basically the same as that in Example 1, except that the amount of the third monomer used in Example 8 is different. Specifically, step S5 of Example 8 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9400 g) is added; butyl acrylate (500 g) is added; and 4-aminostyrene (100 g) is added.

[0086] The thermal stability test results of the PVC resins in Examples 1 and 6-8 are shown in Table 4.

[0087] Table 4: Thermal stability test results of PVC resins in Examples 1 and 6-8

[0088]

[0089] As can be seen from the test data in Table 4, the thermal decomposition time increases with the increase of the amount of the third monomer, but the increasing trend of thermal decomposition time is no longer obvious when the content continues to increase from 0.75% to 1.0%. Therefore, the maximum content of the third monomer in this invention is limited to 1.0%.

[0090] Example 9

[0091] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 9 is basically the same as that in Example 1, except that the second monomer in Example 9 is different. Specifically, step S5 of Example 9 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9450 g) is added; vinyl laurate (500 g) is added; and 4-aminostyrene (50 g) is added.

[0092] Example 10

[0093] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 10 is basically the same as that in Example 1, except that the second monomer in Example 10 is different. Specifically, step S5 of Example 10 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9450 g) is added; vinyl isobutyl ether (500 g) is added; and 4-aminostyrene (50 g) is added.

[0094] Example 11

[0095] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 11 is basically the same as that in Example 1, except that the second monomer in Example 11 is different. Specifically, step S5 of Example 11 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9450 g) is added; vinyl ethyl ether (500 g) is added; and 4-aminostyrene (50 g) is added.

[0096] Example 12

[0097] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 12 is basically the same as that in Example 1, except that the second monomer in Example 12 is different. Specifically, step S5 of Example 12 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9450 g) is added; vinyl acetate (500 g) is added; and 4-aminostyrene (50 g) is added.

[0098] The test results of the flowability of the PVC resins in Examples 1, 9-12, and Comparative Example 2 are shown in Table 5.

[0099] Table 5: Flowability test results of PVC resins in Examples 1 and 9-12

[0100]

[0101] As can be seen from the test data in Table 5, all types of second monomers used in this invention can significantly improve the flowability of PVC resin.

[0102] Example 13

[0103] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 13 is basically the same as that in Example 1, except that the third monomer in Example 13 is different. Specifically, step S5 of Example 13 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9450 g) is added; butyl acrylate (500 g) is added; and 4-(dimethylamino)styrene (50 g) is added.

[0104] Example 14

[0105] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 14 is basically the same as that in Example 1, except that the third monomer in Example 14 is different. Specifically, step S5 of Example 14 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9450 g) is added; butyl acrylate (500 g) is added; and N-(2-aminoethyl)acrylamide (50 g) is added.

[0106] Example 15

[0107] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 15 is basically the same as that in Example 1, except that the third monomer in Example 15 is different. Specifically, step S5 of Example 15 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9450 g) is added; butyl acrylate (500 g) is added; and N-(2-(2-aminoethyl)amino)ethyl)acrylamide (50 g) is added.

[0108] Example 16

[0109] The high-mechanical-performance, high-flowability foamed PVC resin for shoe materials in Example 16 is basically the same as that in Example 1, except that the third monomer in Example 16 is different. Specifically, step S5 of Example 16 is as follows: nitrogen gas is introduced to replace the air in the reactor, and this replacement is repeated four times. Stirring is then started, and vinyl chloride monomer (9450 g) is added; butyl acrylate (500 g) is added; and dimethylaminoethyl methacrylate (50 g) is added.

[0110] The thermal decomposition test results of the PVC resins in Examples 1, 13-16, and Comparative Example 2 are shown in Table 6.

[0111] Table 6: Thermal decomposition test results of PVC resin in Examples 1 and 13-16

[0112]

[0113] As can be seen from the test data in Table 6, all types of third monomers used in this invention can significantly improve the thermal stability of PVC resin.

[0114] In summary, this invention modifies PVC resin by using specific types and proportions of second and third monomers, while strictly controlling the polymerization temperature to control the degree of polymerization of the copolymer. This results in a copolymer that possesses high mechanical properties, high melt flowability, and good heat resistance, thus showing promising application prospects in fields such as shoe material foaming.

[0115] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A high-mechanical-performance, high-flowability foamed PVC resin for shoe materials, characterized in that, It is made by polymerization reaction of raw materials including vinyl chloride monomer, second monomer, third monomer, dispersant, initiator, stabilizer, terminator and defoamer; The second monomer is selected from at least one of butyl acrylate, methyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, vinyl lauryl ester, vinyl octyl ether acetate, vinyl isobutyl ether, vinyl ethyl ether, vinyl n-butyl ether, vinyl octadecyl ether, cetyl vinyl ether, vinyl acetate, hydroxyethyl methacrylate, and hydroxyethyl vinyl ether. The third monomer is selected from at least one of 4-aminostyrene, 4-(dimethylamino)styrene, N-(2-aminoethyl)acrylamide, N-(2-(2-aminoethyl)amino)ethyl)acrylamide, dimethylaminoethyl methacrylate, and tert-butylaminoethyl methacrylate.

2. The high mechanical properties and high flowability foamed PVC resin for shoe materials according to claim 1, characterized in that, The amount of the second monomer is 2.5% to 7.5% of the total mass of the monomers; the amount of the third monomer is 0.1% to 1.0% of the total mass of the monomers.

3. The high mechanical properties and high flowability foamed PVC resin for shoe materials according to claim 1, characterized in that, The polymerization reaction is carried out at a temperature of 48~52℃.

4. The high mechanical properties and high flowability foamed PVC resin for shoe materials according to claim 1, characterized in that, The dispersant includes a primary dispersant 1, a primary dispersant 2, and a co-dispersant; wherein, the primary dispersant 1 is polyvinyl alcohol with a degree of hydrolysis in the range of 70-90 mol%; the primary dispersant 2 is selected from at least one of methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, and hydroxypropylmethylcellulose; and the co-dispersant is polyvinyl alcohol with a degree of hydrolysis in the range of 45-55 mol%.

5. The high mechanical properties and high flowability foamed PVC resin for shoe materials according to claim 1, characterized in that, The initiator is selected from at least one of tert-butyl peroxyneodecanate, cumyl peroxyneodecanate, di(3,3,5-trimethylhexanoyl)peroxide, and bis(2-ethylhexyl) peroxydicarbonate.

6. The high mechanical properties and high flowability foamed PVC resin for shoe materials according to claim 1, characterized in that, The stabilizer is selected from at least one of ammonia, sodium carbonate, and sodium bicarbonate.

7. The high mechanical properties and high flowability foamed PVC resin for shoe materials according to claim 1, characterized in that, The terminator is selected from at least one of bisphenol A, acetone thiourea, α-methylstyrene, and nonylphenol.

8. The high mechanical properties and high flowability foamed PVC resin for shoe materials according to claim 1, characterized in that, The defoamer is selected from at least one of polysiloxane, organically modified polysiloxane, and polyether-modified organosilicon.

9. The method for preparing the high-mechanical-performance, high-flowability foamed PVC resin for shoe materials according to any one of claims 1-8, characterized in that, Includes the following steps: Dispersant, stabilizer, water, and initiator are added to the reactor. After introducing a protective gas, vinyl chloride monomer, second monomer, and third monomer are added, and polymerization is carried out at 48~52 °C. After a pressure drop of 1 bar, terminator and defoamer are added to obtain foamed PVC resin for shoe materials with high mechanical properties and high flowability.

10. The application of the high mechanical properties and high fluidity PVC resin for shoe material foaming according to any one of claims 1-8 in the fields of shoe material foaming processing, pipe processing, film processing or wire and cable processing.

Images