Cold-resistant foaming material for shoe body

Abstract

The invention relates to the technical field of materials, and discloses a cold-resistant foaming material for shoes, which is prepared by taking EVA (Ethylene Vinyl Acetate) resin as a base material and carrying out banburying and foaming processes on the EVA resin, a rubber additive, a palm fiber reinforcing agent, a cold-resistant auxiliary agent and the like. Wherein the palm fiber can be uniformly dispersed in an EVA resin matrix through interaction between a large number of polyethyleneimine molecular chains on the surface of the palm fiber reinforcing agent and EVA resin molecular chains, and a physical buckle cross-linked structure is formed between the palm fiber reinforcing agent and the EVA resin matrix, so that the palm fiber can efficiently exert the reinforcing and modifying advantages of the palm fiber; the strength of the foaming material is effectively improved, the low-temperature cracking risk of the foaming material can be reduced, and the cold resistance of the foaming material can be effectively improved by adding the cold-resistant additive.

Description

Technical Field

[0001] The invention relates to the technical field of materials, and in particular to a cold-resistant foaming material for a shoe body. Background Art

[0002] EVA resin is a polymer compound formed by the copolymerization of ethylene (ET) and vinyl acetate (VA). This synthetic material is formed by a high-pressure bulk polymerization process, in which ethylene is used as the basic monomer, while vinyl acetate gives EVA a certain flexibility and adhesion. EVA products with different VA contents have different physical properties, but generally have the characteristics of light weight, softness, chemical resistance, good elasticity, and excellent impact resistance. It is precisely because of its excellent physical properties that EVA resin plays an important role in the manufacture of shoe bodies. Especially as a sole material, EVA's high resilience and tension resistance, as well as good thermal insulation properties, make it an ideal choice for making shoe bodies.

[0003] However, in a cold environment, the physical indicators of EVA foam materials will drop significantly, especially when the temperature reaches minus 20 degrees Celsius, the hardness of the EVA foam material will increase significantly, and the mechanical strength and other properties will also be significantly reduced, which may cause the shoe body to break, seriously affecting the quality and service life of the shoe body. Therefore, it is of great significance to enhance and modify the EVA foam material for its application in shoe body materials. Summary of the invention

[0004] In order to solve the problems mentioned in the background technology, the object of the present invention is to provide a cold-resistant foaming material for a shoe body.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A cold-resistant foaming material for a shoe body, made from raw materials including the following weight fractions:

[0007]

[0008] As a further embodiment of the present invention, the rubber additive is selected from any one of ethylene propylene diene rubber, polybutadiene rubber or styrene butadiene rubber.

[0009] As a further embodiment of the present invention, the preparation method of the palm fiber reinforcing agent specifically comprises the following steps:

[0010] Step 1, immersing the palm fiber in a sodium hydroxide solution, dispersing it evenly, maintaining it at a temperature of 50-60° C. for 1-2 hours, taking it out, washing it, and vacuum drying it to form pretreated palm fiber;

[0011] Step 2: Disperse the pretreated palm fiber in tetrahydrofuran, perform ultrasonic treatment for 20-40 minutes, then add the halogenating agent to the formed dispersion, stir and mix at room temperature for 2-4 hours, separate the fiber material, and form the halogenated palm fiber;

[0012] Step 3: Add the halogenated palm fiber to toluene, and after ultrasonic dispersion, add polyethyleneimine to the dispersion. After the addition, control the temperature to 70-80°C, keep stirring for 12-16 hours, stop heating, cool and discharge, separate the product, and obtain the palm fiber enhancer.

[0013] As a further solution of the present invention, in step 1, the mass fraction of the sodium hydroxide solution is 10-20%.

[0014] As a further embodiment of the present invention, in step 2, the halogenating agent is selected from any one of bromoacetyl bromide, bromoacetyl chloride, 4-bromobutyryl chloride or 4-chlorobutyryl chloride.

[0015] As a further embodiment of the present invention, in step three, the number average molecular weight of the polyethyleneimine is 10,000.

[0016] As a further embodiment of the present invention, in step three, the mass ratio of the halogenated palm fiber to polyethyleneimine is 1:6-10.

[0017] In the above technical scheme, the palm fiber is firstly subjected to an alkalization treatment so that a large number of active hydroxyl groups can be exposed on its surface, and then a halogenating agent is used to perform surface modification treatment on the palm fiber to obtain a palm fiber having a large number of halogen substituents on its surface. Finally, polyethyleneimine is grafted onto the surface of the palm fiber through a substitution reaction to obtain a palm fiber modified body having a surface coated with macromolecular polyethyleneimine, i.e., a palm fiber enhancer.

[0018] As a further solution of the present invention, the cold-resistant auxiliary agent is a mixture of talc and dioctyl oxalate, with a mass ratio of 1:0.5-0.8.

[0019] In the above technical scheme, talcum powder can act as a heterogeneous nucleation point in the EVA resin foaming process, which is beneficial to improving the pore structure of the foaming material, and can also improve the cold resistance stability of the foaming material by weakening the mobility of the molecular chains. Dioctyl oxalate can reduce the van der Waals force between EVA resin molecules, promote the separation of molecular chains, increase its flexibility and plasticity, and thus prevent the foaming material from breaking due to increased brittleness in a low temperature environment, thereby improving the cold resistance of the foaming material.

[0020] As a further embodiment of the present invention, the vulcanizing agent is 2,4-di-tert-butyl cumene peroxide; and the foaming agent is AC foaming agent.

[0021] As a further embodiment of the present invention, the method for preparing the cold-resistant foaming material comprises the following steps:

[0022] The first step is to prepare all the raw materials according to the weight proportions, then take the EVA resin, rubber additives, palm fiber reinforcement and cold-resistant additives, put them into the internal mixer, and mix them at a temperature of 80-90°C for 5-15 minutes, then add the vulcanizing agent and foaming agent into the internal mixer, and increase the temperature to 100-110°C, and continue mixing for 1-3 minutes to form a mixed material;

[0023] The second step is to perform compression molding and foaming on the mixed material.

[0024] Beneficial effects of the present invention:

[0025] The present invention prepares a palm fiber reinforcing agent and utilizes the interaction between a large number of polyethyleneimine molecular chains on the surface of the palm fiber and the EVA resin molecular chains, so that the palm fiber can be evenly dispersed in the EVA resin matrix and a physical snap-on cross-linking structure is formed between the palm fiber and the EVA resin matrix, so that the palm fiber can effectively exert its own reinforcing and modified advantages, the strength of the foaming material is effectively improved, the risk of low-temperature cracking of the foaming material is reduced, and the cold-resistant performance of the foaming material can be effectively improved by adding a cold-resistant auxiliary agent.

[0026] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Preparation Example 1

[0029] Preparation of palm fiber reinforcement:

[0030] Step 1, immersing 6 g of palm fiber in 100 mL of a 20% sodium hydroxide solution, dispersing the fiber uniformly, maintaining the solution at 55° C. for 2 h, taking the solution out, washing the solution, and vacuum drying the solution to form pretreated palm fiber;

[0031] Step 2: Disperse 3.8 g of pretreated palm fiber in tetrahydrofuran, perform ultrasonic treatment for 30 min, then add 6.5 g of bromoacetyl bromide to the formed dispersion, stir and mix at room temperature for 3 h, separate the fiber material, and form halogenated palm fiber;

[0032] Step 3: Add 1.6 g of halogenated palm fiber to toluene, and after ultrasonic dispersion, add 12 g of polyethyleneimine with a number average molecular weight of 10,000 to the dispersion. After the addition, control the temperature to 75°C, keep stirring for 16 hours, stop heating, cool and discharge, separate the product, and you can get a palm fiber enhancer.

[0033] The organic element content of the palm fiber reinforcer was analyzed using an organic element analyzer. The test results showed that the percentage of carbon element was 42.88% and the percentage of nitrogen element was 6.91%. It is speculated that the nitrogen element comes from polyethyleneimine.

[0034] Example 1

[0035] A cold-resistant foaming material for a shoe body, made from raw materials including the following weight fractions:

[0036]

[0037] The preparation method of the cold-resistant foaming material is as follows:

[0038] The first step is to prepare all the raw materials according to the weight proportions, then take EVA resin, EPDM rubber, palm fiber reinforcement agent and cold-resistant additive, put them into an internal mixer, and mix them at 80°C for 15 minutes, then add 2,4-di-tert-butyl peroxide isopropylbenzene and AC foaming agent into the internal mixer, and raise the temperature to 100°C, and continue mixing for 3 minutes to form a mixed material;

[0039] The second step is to control the temperature to 160°C and perform compression molding and foaming on the mixed material for 10 minutes.

[0040] The EV content of the EVA resin is less than 15%; the palm fiber reinforcing agent adopts the palm fiber reinforcing agent prepared in Preparation Example 1; the cold-resistant auxiliary agent is a mixture of talcum powder and dioctyl oxalate in a mass ratio of 1:0.5, and the same applies to the following.

[0041] Example 2

[0042] A cold-resistant foaming material for a shoe body, made from raw materials including the following weight fractions:

[0043]

[0044]

[0045] The preparation method of the cold-resistant foaming material is as follows:

[0046] The first step is to prepare all the raw materials according to the weight proportions, then take EVA resin, polybutadiene rubber, palm fiber reinforcement agent and cold-resistant additive, put them into an internal mixer, and mix them at a temperature of 85°C for 10 minutes, then add 2,4-di-tert-butyl peroxide isopropylbenzene and AC foaming agent into the internal mixer, and raise the temperature to 110°C, and continue mixing for 2 minutes to form a mixed material;

[0047] The second step is to control the temperature to 160°C and perform compression molding and foaming on the mixed material for 10 minutes.

[0048] Example 3

[0049] A cold-resistant foaming material for a shoe body, made from raw materials including the following weight fractions:

[0050]

[0051] The preparation method of the cold-resistant foaming material is as follows:

[0052] The first step is to prepare all the raw materials according to the weight proportions, then take EVA resin, styrene-butadiene rubber, palm fiber reinforcing agent and cold-resistant additive, put them into an internal mixer, and mix them at 90°C for 5 minutes, then add 2,4-di-tert-butyl peroxide isopropylbenzene and AC foaming agent into the internal mixer, and raise the temperature to 110°C, and continue mixing for 1 minute to form a mixed material;

[0053] The second step is to control the temperature to 160°C and perform compression molding and foaming on the mixed material for 10 minutes.

[0054] Comparative Example 1

[0055] A cold-resistant foaming material for a shoe body, made from raw materials including the following weight fractions:

[0056]

[0057] The preparation method of the cold-resistant foaming material is as follows:

[0058] The first step is to prepare all the raw materials according to the weight proportions, then take EVA resin, polybutadiene rubber, palm fiber and cold-resistant additive, put them into an internal mixer, and mix them at a temperature of 85°C for 10 minutes, then add 2,4-di-tert-butyl peroxide isopropylbenzene and AC foaming agent into the internal mixer, and raise the temperature to 110°C, and continue mixing for 2 minutes to form a mixed material;

[0059] The second step is to control the temperature to 160°C and perform compression molding and foaming on the mixed material for 10 minutes.

[0060] Comparative Example 2

[0061] A cold-resistant foaming material for a shoe body, made from raw materials including the following weight fractions:

[0062]

[0063] The preparation method of the cold-resistant foaming material is as follows:

[0064] The first step is to prepare all the raw materials according to the weight proportions, then take EVA resin, polybutadiene rubber and cold-resistant additive, put them into an internal mixer, and mix them at a temperature of 85°C for 10 minutes, then add 2,4-di-tert-butyl peroxide isopropylbenzene and AC foaming agent into the internal mixer, and raise the temperature to 110°C, and continue mixing for 2 minutes to form a mixed material;

[0065] The second step is to control the temperature to 160°C and perform compression molding and foaming on the mixed material for 10 minutes.

[0066] Test Case

[0067] The foaming materials in the embodiments and comparative examples were tested for comprehensive properties, and the results are recorded in Table 1:

[0068] Table 1 - Test results

[0069]

[0070] The tensile strength test standard is GB / T 528-2009; the compression deformation test reference standard is HG / T 2876, the test conditions are 50℃, 6h, and the compression ratio is 50%; the hardness is tested with a hardness tester, and the test conditions are to place samples of the same specifications in an environment of 20℃ and -20℃ for 24h and then take them out for testing.

[0071] The analysis and test results show that the use of the palm fiber reinforcement in Preparation Example 1 of the present invention as an additive can make the EVA foam material exhibit excellent mechanical properties, and under the action of the cold-resistant additive, the cold-resistant performance of the foam material can also be guaranteed.

[0072] After replacing the palm fiber reinforcement with unmodified palm fiber, the mechanical strength of the foamed material is obviously reduced. This is because there are interface problems after the palm fiber is blended with EVA resin, which cannot effectively exert its advantages. After directly removing the palm fiber reinforcement, the mechanical strength of the material is further reduced.

[0073] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

[0074] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cold-resistant foaming material for a shoe body, characterized in that: Made from raw materials including the following weight fractions:

2. The cold-resistant foaming material for shoe body according to claim 1, characterized in that: The rubber additive is selected from any one of ethylene propylene diene rubber, polybutadiene rubber or styrene butadiene rubber.

3. The cold-resistant foaming material for shoe body according to claim 1, characterized in that: The preparation method of the palm fiber reinforcing agent specifically comprises the following steps: Step 1, immersing the palm fiber in a sodium hydroxide solution, dispersing it evenly, maintaining it at a temperature of 50-60° C. for 1-2 hours, taking it out, washing it, and vacuum drying it to form pretreated palm fiber; Step 2: Disperse the pretreated palm fiber in tetrahydrofuran, perform ultrasonic treatment for 20-40 minutes, then add the halogenating agent to the formed dispersion, stir and mix at room temperature for 2-4 hours, separate the fiber material, and form the halogenated palm fiber; Step 3: Add the halogenated palm fiber to toluene, and after ultrasonic dispersion, add polyethyleneimine to the dispersion. After the addition, control the temperature to 70-80°C, keep stirring for 12-16 hours, stop heating, cool and discharge, separate the product, and obtain the palm fiber enhancer.

4. The cold-resistant foaming material for shoe body according to claim 3, characterized in that: In step 1, the mass fraction of the sodium hydroxide solution is 10-20%.

5. The cold-resistant foaming material for shoe body according to claim 3, characterized in that: In step 2, the halogenating agent is selected from any one of bromoacetyl bromide, bromoacetyl chloride, 4-bromobutyryl chloride or 4-chlorobutyryl chloride.

6. The cold-resistant foaming material for shoe body according to claim 3, characterized in that: In step 3, the number average molecular weight of the polyethyleneimine is 10,000.

7. The cold-resistant foaming material for shoe body according to claim 3, characterized in that: In step 3, the mass ratio of the halogenated palm fiber to polyethyleneimine is 1:6-10.

8. The cold-resistant foaming material for shoe body according to claim 1, characterized in that: The cold-resistant auxiliary agent is a mixture of talcum powder and dioctyl oxalate, with a mass ratio of 1:0.5-0.

8.

9. The cold-resistant foaming material for shoe body according to claim 1, characterized in that: The vulcanizing agent is 2,4-di-tert-butyl cumene peroxide; and the foaming agent is AC foaming agent.

10. The cold-resistant foaming material for shoe body according to claim 1, characterized in that: The preparation method of the cold-resistant foaming material comprises the following steps: The first step is to prepare all the raw materials according to the weight proportions, then take the EVA resin, rubber additives, palm fiber reinforcement and cold-resistant additives, put them into the internal mixer, and mix them at a temperature of 80-90°C for 5-15 minutes, then add the vulcanizing agent and foaming agent into the internal mixer, and increase the temperature to 100-110°C, and continue mixing for 1-3 minutes to form a mixed material; The second step is to perform compression molding and foaming on the mixed material.

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