A modified EVA composite material, its preparation method and application

Abstract

The present invention provides a modified EVA composite material, a preparation method thereof and an application. The preparation method comprises the following steps: S1. Modify EVA to obtain modified EVA; S2. Add the modified EVA obtained in step S1 into a screw extruder to extrude an extruded material, form the extruded material into an EVA sheet through a die head, bond the EVA sheet with a non-woven fabric, and then send the EVA sheet and the non-woven fabric together with a thermoplastic film into a three-roll calender for calendering and forming to obtain a composite material, where the non-woven fabric, the EVA sheet and the thermoplastic film are laminated in sequence from bottom to top; S3. Cut the composite material obtained in step S2 through a trimming machine and a cutting machine to obtain the modified EVA composite material. The modified EVA composite material prepared by the present invention is composed of modified EVA, a non-woven fabric and a thermoplastic film, and has good strength, wear resistance and puncture resistance.

Description

Technical Field

[0001] The present invention relates to a modified EVA composite material, a preparation method thereof, and an application thereof. Background Art

[0002] As a daily necessity in people's lives, shoes have a huge demand. EVA material is one of the main raw materials for shoe-making materials in China at present, and its usage accounts for more than 30% of shoe-making materials. The Chinese chemical name of EVA is ethylene-vinyl acetate copolymer or ethylene-ethyl acetate copolymer, which is mainly polymerized from ethylene monomer and vinyl acetate monomer. The -CH3COO- side chain group is introduced into the main chain of the EVA molecule, reducing the order between its molecules, making the EVA copolymer have good elasticity and low hardness. However, EVA also has the disadvantages of poor abrasion resistance, puncture resistance, and low strength. Therefore, it is necessary to modify the EVA material or compound it with other materials to improve its overall performance, so as to meet various requirements of shoe-making materials.

[0003] Chinese Patent Application CN201711099996.6 discloses "an EVA sole covered with a PU composite film and a manufacturing method thereof". A composite film body is provided on the sole. A first film layer and a second film layer are provided on the composite film body. The first film layer is arranged on the outermost layer of the composite film body and is bonded to the composite film body. The second film layer is located between the composite film body and the sole and is bonded to the composite film body and the sole. The first film layer is made of PU resin material, and the first film layer is directly exposed to the air. The second film layer is made of hot melt adhesive material. The sole is made of EVA material. This invention bonds the first film layer made of PU resin to the EVA sole through the second film layer, having the disadvantages of unsatisfactory bonding force, poor abrasion resistance, puncture resistance, and low strength. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a preparation method of a modified EVA composite material. The obtained modified EVA composite material is composed of modified EVA, non-woven fabric, and a thermoplastic film, and has good strength, abrasion resistance, and puncture resistance.

[0005] To solve the above technical problem, the technical solution of the present invention is:

[0006] A preparation method of a modified EVA composite material, comprising the following steps:

[0007] S1. Add EVA to tetrahydrofuran and mix evenly to obtain solution A. Add 2.0 g of PAMAM to tetrahydrofuran and mix evenly to obtain solution B. Mix solution A, solution B, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and reflux for 5 - 6 hours to obtain a reaction solution. Cool the reaction solution to room temperature and then filter to obtain a solid. Wash the solid with deionized water 3 times and then vacuum dry to constant weight to obtain modified EVA.

[0008] S2. Add the modified EVA prepared in step S1 to a screw extruder for extrusion to obtain an extruded material. Make the extruded material into an EVA sheet through a die head. Bond the EVA sheet with non-woven fabric and then send it together with a thermoplastic film into a three-roll calender for calendering and forming to obtain a composite material. The non-woven fabric, EVA sheet, and thermoplastic film are laminated in sequence from bottom to top.

[0009] S3. Cut the composite material prepared in step S2 through a trimming machine and a cutting machine to obtain a modified EVA composite material.

[0010] Further, in step S1 of the present invention, the vinyl acetate content of EVA is 25%, and the melt index is 2 g / 10 min.

[0011] Further, in step S1 of the present invention, the ratio of EVA to tetrahydrofuran in solution A is 0.8 mmol:1 mL, the ratio of 2.0 g of PAMAM to tetrahydrofuran in solution B is 2 mmol:1 mL, and the ratio of solution A, solution B, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is 50 mL:50 mL:(0.9 - 1.2) g.

[0012] Further, in step S1 of the present invention, the temperature during vacuum drying is 55 °C.

[0013] Further, in step S2 of the present invention, the screw speed of the screw extruder is 75 rpm.

[0014] Further, in step S2 of the present invention, the temperature of the upper roll of the three-roll calender is 60 - 65 °C, the temperature of the middle roll is 65 - 70 °C, and the temperature of the lower roll is 60 - 65 °C.

[0015] Further, in step S2 of the present invention, the non-woven fabric is polypropylene non-woven fabric, the thermoplastic film is made of chlorinated polypropylene, and the thickness ratio of the non-woven fabric, EVA sheet, and thermoplastic film is 1:4:1.

[0016] The present invention also provides a modified EVA composite material obtained by the above preparation method and the application of the modified EVA composite material in shoe-making materials.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention makes a composite material by laminating and forming modified EVA, non-woven fabric, and thermoplastic film, which makes up for the defects of EVA itself. Among them, the modified EVA is made by grafting reaction of EVA and 2.0G PAMAM under the action of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, improving the strength, wear resistance of EVA and its bonding force with non-woven fabric and thermoplastic film; the thermoplastic film is made of chlorinated polypropylene, which has better toughness than polypropylene and can also improve the overall puncture resistance of the composite material. Therefore, the modified EVA composite material prepared by the present invention has good properties such as strength, wear resistance, and puncture resistance. Specific Embodiments

[0019] The following will specifically describe the present invention in conjunction with specific embodiments. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but not to limit the present invention.

[0020] Example 1

[0021] The modified EVA composite material is made by the following steps:

[0022] S1. EVA with a vinyl acetate content of 25% and a melt index of 2 g / 10 min is added to tetrahydrofuran according to the ratio of 0.8 mmol:1 mL and mixed evenly to obtain solution A. 2.0G PAMAM is added to tetrahydrofuran according to the ratio of 2 mmol:1 mL and mixed evenly to obtain solution B. Solution A, solution B, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride are mixed according to the ratio of 50 mL:50 mL:1 g, and refluxed for 5.5 hours to obtain a reaction solution. After cooling the reaction solution to room temperature, it is filtered to obtain a solid. The solid is washed 3 times with deionized water and then vacuum dried at 55 °C to constant weight to obtain modified EVA;

[0023] S2. The modified EVA prepared in step S1 is extruded by a screw extruder with a screw speed of 75 rpm to obtain an extruded material. The extruded material is made into an EVA sheet through a die head. The EVA sheet is bonded to a polypropylene non-woven fabric and then sent together with a thermoplastic film made of chlorinated polypropylene into a three-roll calender for calendering and forming to obtain a composite material. The polypropylene non-woven fabric, EVA sheet, and thermoplastic film are laminated in sequence from bottom to top. The thickness ratio of the polypropylene non-woven fabric, EVA sheet, and thermoplastic film is 1:4:1. The temperature of the upper roll of the three-roll calender is 63 °C, the temperature of the middle roll is 68 °C, and the temperature of the lower roll is 63 °C;

[0024] S3. The composite material prepared in step S2 is cut by a trimming machine and a cutting machine to obtain the modified EVA composite material.

[0025] Example 2

[0026] The modified EVA composite material is prepared by the following steps:

[0027] S1. EVA with a vinyl acetate content of 25% and a melt index of 2 g / 10 min is added to tetrahydrofuran at a ratio of 0.8 mmol:1 mL and mixed evenly to obtain solution A. 2.0G PAMAM is added to tetrahydrofuran at a ratio of 2 mmol:1 mL and mixed evenly to obtain solution B. Solution A, solution B, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride are mixed at a ratio of 50 mL:50 mL:1.2 g, and refluxed for 5 hours to obtain a reaction solution. After cooling the reaction solution to room temperature, it is filtered to obtain a solid. The solid is washed 3 times with deionized water and then vacuum dried at 55 °C to constant weight to obtain the modified EVA;

[0028] S2. The modified EVA prepared in step S1 is extruded by a screw extruder with a screw speed of 75 rpm to obtain an extruded material. The extruded material is made into an EVA sheet through a die head. The EVA sheet is bonded to a polypropylene non-woven fabric and then sent together with a thermoplastic film made of chlorinated polypropylene into a three-roll calender for calendering and forming to obtain a composite material. The polypropylene non-woven fabric, the EVA sheet, and the thermoplastic film are laminated in sequence from bottom to top. The thickness ratio of the polypropylene non-woven fabric, the EVA sheet, and the thermoplastic film is 1:4:1. The temperature of the upper roll of the three-roll calender is 60 °C, the temperature of the middle roll is 65 °C, and the temperature of the lower roll is 60 °C;

[0029] S3. The composite material prepared in step S2 is cut by a trimming machine and a cutting machine to obtain the modified EVA composite material.

[0030] Example 3

[0031] The modified EVA composite material is prepared by the following steps:

[0032] S1. EVA with a vinyl acetate content of 25% and a melt index of 2 g / 10 min is added to tetrahydrofuran at a ratio of 0.8 mmol:1 mL and mixed evenly to obtain solution A. 2.0G PAMAM is added to tetrahydrofuran at a ratio of 2 mmol:1 mL and mixed evenly to obtain solution B. Solution A, solution B, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride are mixed at a ratio of 50 mL:50 mL:0.9 g, and refluxed for 6 hours to obtain a reaction solution. After cooling the reaction solution to room temperature, it is filtered to obtain a solid. The solid is washed 3 times with deionized water and then vacuum dried at 55 °C to constant weight to obtain the modified EVA;

[0033] S2. Add the modified EVA prepared in step S1 to a screw extruder with a screw speed of 75 rpm to obtain an extruded material. Make the extruded material into an EVA sheet through a die head. Bond the EVA sheet to a polypropylene non-woven fabric and then send it together with a thermoplastic film made of chlorinated polypropylene into a three-roll calender for calendering and forming to obtain a composite material. The polypropylene non-woven fabric, EVA sheet, and thermoplastic film are laminated in sequence from bottom to top. The thickness ratio of the polypropylene non-woven fabric, EVA sheet, and thermoplastic film is 1:4:1. The temperature of the upper roll of the three-roll calender is 65 °C, the temperature of the middle roll is 70 °C, and the temperature of the lower roll is 65 °C;

[0034] S3. Cut the composite material prepared in step S2 through a trimming machine and a cutting machine to obtain the modified EVA composite material.

[0035] Example 4

[0036] The modified EVA composite material is made by the following steps:

[0037] S1. Add EVA with a vinyl acetate content of 25% and a melt index of 2 g / 10 min to tetrahydrofuran at a ratio of 0.8 mmol:1 mL and mix evenly to obtain solution A. Add 2.0G PAMAM to tetrahydrofuran at a ratio of 2 mmol:1 mL and mix evenly to obtain solution B. Mix solution A, solution B, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride at a ratio of 50 mL:50 mL:1.1 g, and reflux for 5.2 hours to obtain a reaction solution. Cool the reaction solution to room temperature and then filter to obtain a solid. Wash the solid 3 times with deionized water and then vacuum dry at 55 °C to constant weight to obtain the modified EVA;

[0038] S2. Add the modified EVA prepared in step S1 to a screw extruder with a screw speed of 75 rpm to obtain an extruded material. Make the extruded material into an EVA sheet through a die head. Bond the EVA sheet to a polypropylene non-woven fabric and then send it together with a thermoplastic film made of chlorinated polypropylene into a three-roll calender for calendering and forming to obtain a composite material. The polypropylene non-woven fabric, EVA sheet, and thermoplastic film are laminated in sequence from bottom to top. The thickness ratio of the polypropylene non-woven fabric, EVA sheet, and thermoplastic film is 1:4:1. The temperature of the upper roll of the three-roll calender is 64 °C, the temperature of the middle roll is 69 °C, and the temperature of the lower roll is 64 °C;

[0039] S3. Cut the composite material prepared in step S2 through a trimming machine and a cutting machine to obtain the modified EVA composite material.

[0040] Reference Example 1:

[0041] The difference from Example 1 is that step S1 is not included, and the modified EVA used in step S2 is replaced with EVA having a vinyl acetate content of 25% and a melt index of 2 g / 10 min.

[0042] Comparative Example 2:

[0043] The difference from Example 1 is that the thermoplastic film used in step S2 is made of polypropylene.

[0044] Comparative Example: The example of the Chinese patent with the application number CN201711099996.6.

[0045] Test Example 1: Strength test

[0046] Test method: The modified EVA materials prepared in Examples 1-4 and Comparative Example 1 and the EVA soles prepared in the comparative example were made into standard specimens, and then the tensile strength of each standard specimen was measured respectively using an electronic universal testing machine with reference to GB / T 6344-2008.

[0047] The test results are shown in Table 1:

[0048] Tensile strength (MPa) Example 1 11.5 Example 2 11.2 Example 3 11.6 Example 4 11.3 Reference Example 1 10.8 Comparative Example 10.9

[0049] Table 1

[0050] As can be seen from Table 1, the tensile strengths of Examples 1-4 of the present invention are all higher than those of the comparative example, indicating that the modified EVA composite material prepared by the present invention has good strength. Some raw materials and steps of Comparative Example 1 are different from those of Example 1. Compared with Example 1, the tensile strength of Comparative Example 1 has decreased, indicating that the modified EVA used in the present invention can improve the strength of the composite material compared with EVA.

[0051] Test Example 2: Abrasion resistance test

[0052] Test method: The modified EVA materials prepared in Examples 1-4 and Comparative Example 1 and the EVA soles prepared in the comparative example were cut into samples, and then the abrasion loss of each sample was measured respectively using a DIN abrasion tester with reference to ISO 4649-2006.

[0053] The lower the abrasion loss, the better the abrasion resistance. The test results are shown in Table 2:

[0054] <![CDATA[Wear amount (mm 3 )]]> Example 1 101 Example 2 105 Example 3 104 Example 4 102 Reference Example 1 119 Comparative Example 110

[0055] Table 2

[0056] As can be seen from Table 2, the wear amounts of Examples 1-4 of the present invention are all lower than those of the comparative examples, indicating that the modified EVA composite materials prepared by the present invention have good wear resistance. Some raw materials and steps of Comparative Example 1 are different from those of Example 1. Compared with Example 1, the wear amount of Comparative Example 1 increases, indicating that compared with EVA, the modified EVA used in the present invention can improve the wear resistance of the composite material.

[0057] Test Example Three: Puncture Resistance Test

[0058] Test method: The modified EVA materials prepared in Examples 1-4 and Comparative Example 2 and the EVA soles prepared in the comparative example were cut into samples with an average thickness of 1 cm, and then the puncture strength testers were used to measure the puncture strength of each sample. The diameter of the steel needle was 1 mm, the radius of the spherical tip was 0.5 mm, and the puncture speed was 50 mm / min.

[0059] The higher the puncture resistance, the better the puncture resistance performance. The test results are shown in Table 3:

[0060] Puncture resistance strength (N) Example 1 14.3 Example 2 14.2 Example 3 13.9 Example 4 14.0 Reference Example 2 12.1 Comparative Example 13.7

[0061] Table 3

[0062] As can be seen from Table 3, the puncture strengths of Examples 1-4 of the present invention are all higher than those of the comparative examples, indicating that the modified EVA composite materials prepared by the present invention have good puncture resistance. Some raw materials and steps of Comparative Example 2 are different from those of Example 1. Compared with Example 1, the puncture strength of Comparative Example 2 decreases, indicating that compared with the thermoplastic film made of polypropylene, the thermoplastic film made of chlorinated polypropylene used in the present invention can improve the puncture resistance of the composite material.

[0063] The above embodiments merely illustrate the principles and effects of the present invention and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A preparation method of a modified EVA composite material, characterized in that: It includes the following steps: S1. Add EVA into tetrahydrofuran and mix evenly to obtain solution A. Add 2.0 g of PAMAM into tetrahydrofuran and mix evenly to obtain solution B. Mix solution A, solution B, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and carry out a reflux reaction for 5 - 6 hours to obtain a reaction solution. Cool the reaction solution to room temperature and then filter to obtain a solid. Wash the solid 3 times with deionized water and then vacuum dry it to constant weight to obtain modified EVA. The ratio of EVA to tetrahydrofuran in solution A is 0.8 mmol:1 mL, the ratio of 2.0 g of PAMAM to tetrahydrofuran in solution B is 2 mmol:1 mL, and the ratio of solution A, solution B, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is 50 mL:50 mL:(0.9 - 1.2) g; S2. Add the modified EVA prepared in step S1 into a screw extruder and extrude to obtain an extruded material. Make the extruded material into an EVA sheet through a die head. Bond the EVA sheet with non-woven fabric and then send them together with a thermoplastic film into a three-roll calender for calendering and forming to obtain a composite material. The non-woven fabric, EVA sheet, and thermoplastic film are laminated in sequence from bottom to top. The non-woven fabric is a polypropylene non-woven fabric, and the thermoplastic film is made of chlorinated polypropylene. The thickness ratio of the non-woven fabric, EVA sheet, and thermoplastic film is 1:4:1; S3. Cut the composite material prepared in step S2 through a trimming machine and a cutting machine to obtain a modified EVA composite material.

2. The preparation method of a modified EVA composite material according to claim 1, characterized in that: In step S1, the vinyl acetate content of EVA is 25%, and the melt index is 2 g / 10 min.

3. The preparation method of a modified EVA composite material according to claim 1, characterized in that: In step S1, the temperature during vacuum drying is 55 °C.

4. The preparation method of a modified EVA composite material according to claim 1, characterized in that: In step S2, the screw speed of the screw extruder is 75 rpm.

5. The preparation method of a modified EVA composite material according to claim 1, characterized in that: In step S2, the temperature of the upper roll of the three-roll calender is 60 - 65 °C, the temperature of the middle roll is 65 - 70 °C, and the temperature of the lower roll is 60 - 65 °C.

6. A modified EVA composite material obtained by the preparation method according to any one of claims 1 to 5.

7. The application of the modified EVA composite material according to claim 6 in shoe-making materials.