High-resilience light foaming solid tire and preparation method thereof

Abstract

According to the high-resilience light foaming solid tire and the preparation method thereof, through ternary blending modification of EVA, POE and LDPE, the falling ball resilience rate of the prepared solid tire reaches 30% or above, the highest falling ball resilience rate can reach about 36%, and the solid tire has the advantages of being high in elasticity, light in weight, good in damping effect, smooth in surface and especially suitable for small vehicles; the solid foaming tire can be used as a small carrier such as a baby carriage, a baby stroller and a child toy car, and solves the problems of poor rebound resilience and poor comfort of the existing solid foaming tire.

Description

Technical Field

[0001] This invention relates to the field of tire technology, specifically to a high-resilience lightweight foamed solid tire and its preparation method. Background Technology

[0002] Currently, tires for small vehicles (such as strollers) on the market are mainly divided into two categories. The first is pneumatic tires, which are comfortable but prone to leaks and require troublesome maintenance. The second is ordinary solid tires, such as the common EVA or LDPE single-component foam type, which has the advantage of low cost, but has defects such as poor elasticity (rebound rate below 25%), poor shock absorption, and poor comfort, and needs improvement. Summary of the Invention

[0003] To address at least one of the aforementioned technical deficiencies, the present invention provides the following technical solution:

[0004] This application discloses a high-resilience, lightweight, foamed solid tire, which, by weight, comprises the following components: 10-20 parts EVA, 10-20 parts POE, 3-8 parts LDPE, 1.0-3.0 parts foaming agent, 0.2-0.8 parts crosslinking agent, and 0.1-0.8 parts zinc stearate.

[0005] EVA stands for ethylene-vinyl acetate copolymer, POE stands for polyoctene elastomer, and LDPE stands for low-density polyethylene resin.

[0006] Furthermore, the weight ratio of EVA to POE is 1:1, and the ratio of LDPE to the total mass of EVA, POE, and LDPE is 1-2:10.

[0007] Furthermore, by mass, it includes the following components: 15 parts EVA, 15 parts POE, 5 parts LDPE, 2.0 parts foaming agent, 0.4 parts crosslinking agent, and 0.3 parts zinc stearate.

[0008] Furthermore, the EVA contains 18%-28% vinyl acetate and has a melt index of 2-6 g / 10 min; the POE is an octene copolymer with a density of 0.855-0.885 g / cm³.

[0009] Furthermore, the foaming agent is azodicarbonamide or 4,4'-oxobisbenzenesulfonylhydrazine, and the particle size of the foaming agent is 5-8 μm.

[0010] This application discloses a method for preparing a high-resilience lightweight foamed solid tire, comprising the following steps: First, the mixture is stirred and mixed. EVA, POE, LDPE and zinc stearate are added to the internal mixer according to the material ratio in claim 1. The mixture is stirred at 100-110℃ for 5-8 minutes. After the materials are melted and mixed evenly, foaming agent and crosslinking agent are added and the mixture is stirred at 105-115℃ for 3-5 minutes to obtain the mixed rubber compound. Second, the mixed rubber compound obtained in the first step is transferred to the open mill and passed through a thin mill 3-4 times to obtain the rubber sheet. Third, after cutting the film obtained in the second step, it is transferred into the mold cavity for molding and foaming. The foaming temperature is 160-175℃, the pressure is 10-15MPa, and the time is 8-15min. Fourth, cooling and shaping: after foaming in step three, the film is kept under pressure and cooled to below 50°C, and then removed to obtain the tire.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention modifies solid tires by ternary blending of EVA, POE, and LDPE, achieving a ball rebound rate of over 30%, with a maximum of around 36%. These tires are characterized by high elasticity, light weight, and good shock absorption, and have a smooth surface. They are particularly suitable for small vehicles such as strollers, baby carriages, and children's toy cars, solving the problems of poor resilience and uncomfort in existing solid foam tires. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is an SEM image of the tire cross-section in Example 1.

[0014] Figure 2 This is a comparison chart of the rebound rates of the tires prepared in Comparative Examples 1-2 and Examples 1-7. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0016] The materials are as follows: EVA: Vinyl acetate content is 28%, melt index is 5g / 10min, Dow Chemical ELVAX 265.

[0017] POE: Octene copolymer, density 0.865 g / cm³, Dow Chemical ENGAGE 8150.

[0018] LDPE: Dow Chemical LDPE 5200G (USA).

[0019] Foaming agent: azodicarbonamide, with a particle size of 5-8 μm.

[0020] Crosslinking agent: Akzo BC-FF from Shanghai Yushi Plastics Co., Ltd.

[0021] Example 1 A method for preparing a high-resilience lightweight foamed solid tire includes the following steps: First, the mixture is prepared by internal mixing. By weight, 15 parts of EVA, 15 parts of POE, 5 parts of LDPE, 2.0 parts of foaming agent, 0.4 parts of crosslinking agent, and 0.3 parts of zinc stearate are added to the internal mixer according to the material ratio. The mixture is then mixed at 105°C for 6 minutes. After the materials are melted and mixed evenly, the foaming agent and crosslinking agent are added, and the mixture is further mixed at 110°C for 4 minutes to obtain the mixed rubber compound.

[0022] Second, the mixed rubber compound obtained in the first step is transferred to the open mill. After passing through the thin mill four times, the roller gap is adjusted to pull out a sheet of rubber of the predetermined thickness.

[0023] Third, after cutting the film obtained in the second step, it is transferred into the mold cavity for molding and foaming. The foaming temperature is 170℃, the pressure is 12MPa, and the time is 10min.

[0024] Fourth, cooling and shaping: after foaming in step three, the film is kept under pressure and cooled to 45°C, then the mold is opened and the tire is obtained.

[0025] Example 2 Compared with Example 1, the difference is that in this example, there are 12 parts of EVA, 18 parts of POE, and 4 parts of LDPE, while the rest are the same.

[0026] Example 3 Compared with Example 1, the difference is that in this example, there are 18 parts of EVA, 12 parts of POE, and 6 parts of LDPE, while the rest are the same.

[0027] Example 4 Compared with Example 1, the difference is that in this example, there are 10 parts of EVA, 20 parts of POE, and 8 parts of LDPE, while the rest are the same.

[0028] Example 5 Compared with Example 1, the difference is that in this example, there are 20 parts of EVA, 10 parts of POE, and 3 parts of LDPE, while the rest are the same.

[0029] Example 6 Compared with Example 1, the difference is that in this example, there are 14 parts of EVA, 14 parts of POE, and 7 parts of LDPE, while the rest are the same.

[0030] Example 7 Compared with Example 1, the difference is that in this example, there are 16 parts of EVA, 16 parts of POE, and 4 parts of LDPE, while the rest are the same.

[0031] Comparative Example 1 Compared with Example 1, the difference is that in this example, there are 20 parts of EVA, 0 parts of POE, and 5 parts of LDPE, while the rest are the same.

[0032] Comparative Example 2 Compared with Example 1, the difference is that in this example, there are 10 parts of EVA, 10 parts of POE, and 0 parts of LDPE, while the rest are the same.

[0033] The tires prepared in the above embodiments and comparative examples were tested for performance, including their ball rebound rate. Figure 2 As shown in Table 1.

[0034] Table 1

[0035] As can be seen from Table 1, the tire prepared in Example 1 with a mass ratio of EVA, POE, and LDPE of 3:3:1 exhibits the best rebound rate. When any component is missing, as shown in Comparative Examples 1 and 2, the rebound rate of the prepared tires decreases significantly.

[0036] Density, surface hardness, and compression set were measured simultaneously. The density of the tires prepared in each example ranged from 0.26 to 0.32 g / cm³. 3 Within the specified range, the product floats on water. The tires prepared in each embodiment have a surface hardness of Shore C 50-60, meeting the comfort requirements of small vehicles. The tires prepared in each embodiment exhibit compression set <15% (70℃×22h) and excellent resilience.

[0037] In addition, such as Figure 1 As shown in the cross-sectional view of the tire, the pore distribution is relatively uniform, which is a significant change brought about by the addition of LDPE.

[0038] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A high-resilience, lightweight, foamed solid tire, characterized in that, By mass, it includes the following components: 10-20 parts EVA, 10-20 parts POE, 3-8 parts LDPE, 1.0-3.0 parts foaming agent, 0.2-0.8 parts crosslinking agent, and 0.1-0.8 parts zinc stearate.

2. The high-resilience lightweight foam solid tire as described in claim 1, characterized in that: The weight ratio of EVA to POE is 1:1, and the ratio of LDPE to the total mass of EVA, POE, and LDPE is 1-2:

10.

3. The high-resilience lightweight foam solid tire as described in claim 1, characterized in that: By mass, it includes the following components: 15 parts EVA, 15 parts POE, 5 parts LDPE, 2.0 parts foaming agent, 0.4 parts crosslinking agent, and 0.3 parts zinc stearate.

4. The high-resilience lightweight foam solid tire as described in claim 1, characterized in that: The EVA contains 18%-28% vinyl acetate and has a melt index of 2-6 g / 10 min; the POE is an octene copolymer with a density of 0.855-0.885 g / cm³.

5. A high-resilience lightweight foam solid tire as described in claim 1, characterized in that: The foaming agent is azodicarbonamide or 4,4'-oxobisbenzenesulfonyl hydrazine, and the particle size of the foaming agent is 5-8 μm.

6. A method for preparing a high-resilience lightweight foamed solid tire, characterized in that: Includes the following steps: First, the mixture is stirred and mixed. EVA, POE, LDPE and zinc stearate are added to the internal mixer according to the material ratio in claim 1. The mixture is stirred at 100-110℃ for 5-8 minutes. After the materials are melted and mixed evenly, foaming agent and crosslinking agent are added and the mixture is stirred at 105-115℃ for 3-5 minutes to obtain the mixed rubber compound. Second, the mixed rubber compound obtained in the first step is transferred to the open mill and passed through a thin mill 3-4 times to obtain the rubber sheet. Third, after cutting the film obtained in the second step, it is transferred into the mold cavity for molding and foaming. The foaming temperature is 160-175℃, the pressure is 10-15MPa, and the time is 8-15min. Fourth, cooling and shaping: after foaming in step three, the film is kept under pressure and cooled to below 50°C, and then removed to obtain the tire.

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