Ejection anti-cracking transparent rubber and production process thereof

Abstract

The invention relates to the field of rubber materials, in particular to a transparent rubber material, and particularly discloses ejection anti-cracking transparent rubber and a production process thereof.The ejection anti-cracking transparent rubber comprises main materials and auxiliaries, the main materials comprise butadiene rubber, polybutadiene rubber and surface-modified nano-silicon dioxide, and the auxiliaries comprise polybutadiene rubber, polybutadiene rubber and surface-modified nano-silicon dioxide; the auxiliary agent comprises a composite anti-aging agent, peroxide and / or an assistant cross-linking agent. According to the transparent rubber material disclosed by the invention, by optimizing material components and structural design, the durability and environmental adaptability of the transparent rubber material can be remarkably improved, and the problem of product cracking in the prior art can be effectively improved. The steps and parameter setting of the production process method are more beneficial to improving the product quality.

Description

Technical Field

[0001] The present invention relates to the field of rubber materials, in particular to transparent rubber materials. Background Art

[0002] With increasing demand for aesthetically pleasing and functional materials across the industrial and consumer goods sectors, transparent rubber, due to its excellent light transmittance, flexibility, and sealing properties, is widely used in medical devices, electronic equipment seals, optical components, and high-end consumer goods. Transparent rubber products vary depending on their application, and some of their properties also differ. Currently, in some areas, existing transparent rubber suffers from a serious and widespread problem with long-term use: cracking. This problem directly impacts the functionality of the transparent rubber and the aesthetic appearance of the products it is used in.

[0003] In view of this, the inventors of this case conducted in-depth research on the cracking problem of existing transparent rubber and carried out improved research and development, which led to the creation of this case.

[0004] However, traditional transparent rubber generally suffers from severe cracking after long-term use. To solve the above problem, this technology proposes a new type of crack-resistant transparent injection rubber component and process. By optimizing the material composition and structural design, its durability and environmental adaptability are significantly improved. Summary of the Invention

[0005] The object of the present invention is to provide an injection-molded anti-cracking transparent rubber which can significantly improve its durability and environmental adaptability by optimizing material composition and structural design.

[0006] Another object of the present invention is to provide a production process for the above-mentioned injection-molded anti-cracking transparent rubber.

[0007] To achieve the above object, the technical solution of the present invention is: an injection-molded anti-cracking transparent rubber, comprising a main ingredient and an auxiliary agent, wherein the main ingredient comprises butadiene rubber, polybutadiene rubber and surface-modified nano-silica.

[0008] The butadiene rubber adopts the model BR1208, the polybutadiene rubber adopts the model JSR810, and the surface-modified nano-silica adopts a particle size of 10-20 nm.

[0009] The butadiene rubber accounts for 28-38 parts of the total weight, the polybutadiene rubber accounts for 33-42 parts of the total weight, and the surface-modified nano-silica accounts for 15-25 parts of the total weight.

[0010] The surface modified nano-silica accounts for 18-22 parts of the total weight.

[0011] The surface modified nano-silica accounts for 20 parts of the total weight.

[0012] The auxiliary agent includes a composite anti-aging agent, a peroxide and / or a co-crosslinking agent.

[0013] The composite anti-aging agent is a composite anti-aging agent composed of a light stabilizer (HALS) and a phosphite, the peroxide is a co-vulcanizing agent (BIBP), and the co-crosslinking agent is trimethylolpropane trimethacrylate (TMPTMA).

[0014] The auxiliary agent includes a composite anti-aging agent, a peroxide and a cross-linking agent, wherein the composite anti-aging agent accounts for 1-3 parts by weight, the peroxide accounts for 1.5-2 parts by weight, and the cross-linking agent accounts for 1-1.5 parts by weight.

[0015] A production process for injection molding crack-resistant transparent rubber, the production process steps are as follows:

[0016] In the first step, the weighed butadiene rubber BR1208 and polybutadiene rubber JSR810 are mixed in a mixer for 90-100 seconds at a temperature of 100-110°C.

[0017] The second step is to pour the additive into the internal mixer that has completed the first step, and pour in 1 / 2 of the surface-modified nano-silica, and mix for 60-70 seconds at a temperature of 110-115°C;

[0018] The third step is to pour the remaining 1 / 2 of the surface modified nano-silica into the internal mixer that has completed the second step, and mix for 60-70 seconds at a temperature of 115-120°C.

[0019] Step 4: After completing step 3, the internal mixer continues to mix at 120-125°C for 120-140 seconds;

[0020] Step 5: After completing step 4, obtain the plasticized transparent material from the internal mixer, pour the transparent material into the turbine and continue to plasticize for at least 190 seconds, then take it out and granulate it to obtain a granular transparent material;

[0021] Step 6: Pour the granular transparent material into the hopper of the injection molding machine. Vulcanization temperature is 155±10℃, pressure is 155±5KG / cm2, and vulcanization time is set according to the quality of the product.

[0022] By adopting the above technical solution, the present invention achieves the following beneficial effects: The crack-resistant transparent rubber produced by injection molding using the above-mentioned composition ratio comprises surface-modified nano-silica as its main ingredient, which acts as a transparent reinforcing agent. A silane coupling agent (such as Si-69) chemically bonds with the rubber matrix, forming a uniform three-dimensional network structure and improving tensile strength and tear resistance. Furthermore, additives are used to synergistically resist aging and increase crosslink density and network stability. A composite anti-aging agent, formulated by combining a hindered amine light stabilizer (HALS) with a phosphite antioxidant, inhibits photo-oxidative aging through a dual mechanism of free radical capture and peroxide decomposition. Furthermore, crosslink density and network stability are enhanced through the vulcanization of di-tert-butyl peroxide isopropyl benzene and trimethylolpropane trimethylolacrylate, thereby reducing stress concentration points. This invention effectively alleviates the cracking problem of existing products and better achieves the aforementioned objectives. DETAILED DESCRIPTION

[0023] In order to further explain the technical solution of the present invention, the present invention is described in detail below through specific embodiments.

[0024] The invention discloses an injection-molded anti-cracking transparent rubber, comprising a main material and an auxiliary agent. The main material mainly comprises butadiene rubber, polybutadiene rubber and surface-modified nano-silica. The auxiliary agent in this embodiment mainly comprises a composite anti-aging agent, a peroxide and a cross-linking agent.

[0025] The butadiene rubber is mainly used as a base material. The existing material has the characteristics of high transparency and aging resistance. In this embodiment, the butadiene rubber with a model of BR1208 is used.

[0026] The polybutadiene rubber is mainly used as a base material. The existing material has the characteristics of high transparency and aging resistance. In this embodiment, the polybutadiene rubber with the model number of JSR810 is used.

[0027] The surface-modified nano-silica is mainly used as a transparent reinforcing material, an existing material, to improve the mechanical properties of the material. In this embodiment, the material is selected to have a particle size of 10-20 nm.

[0028] The composite anti-aging agent is prepared by compounding a colorless hindered amine light stabilizer (HALS) and a phosphite antioxidant.

[0029] The peroxide is di-tert-butyl cumene peroxide (curing agent BIBP).

[0030] The auxiliary cross-linking agent is trimethylolpropane trimethylpropenoate (TMPTMA).

[0031] Through trial production experiments and test comparisons, it was concluded that the transparent rubber material made with the following material ratio range has good properties in many aspects. Specifically, the butadiene rubber accounts for 28-38 parts of the total weight, the polybutadiene rubber accounts for 33-42 parts of the total weight, the surface-modified nano-silica accounts for 15-25 parts of the total weight, the composite anti-aging agent accounts for 1-3 parts of the total weight, the peroxide accounts for 1.5-2 parts of the total weight, and the co-crosslinking agent accounts for 1-1.5 parts of the total weight.

[0032] Due to the lack of reinforcing fillers such as carbon black in existing transparent rubber components, the mechanical properties of transparent rubber (such as tear resistance and fatigue resistance) are poor, resulting in cracks easily generated under dynamic stress or environmental aging (ultraviolet rays, ozone). Through this mechanism study, the present invention has improved the above-mentioned material components, mainly including the application of surface-modified nano-silica and the selection and application of improved additives, thereby achieving synergistic reinforcement, anti-aging optimization, interface stability control, and suppression of crack initiation and propagation. Specifically:

[0033] 1. Nanocomposite reinforcement technology: The above-mentioned surface-modified nano-silica is used as a transparent reinforcing agent with a particle size of 10-20 nm, which can form a highly dispersed silica network. The surface-modified nano-silica is modified by a silane coupling agent (such as Si-69), which can achieve chemical bonding with the rubber of the matrix material to form a uniform three-dimensional network structure, thereby improving tensile strength and tear resistance.

[0034] 2. A synergistic anti-aging system. The aforementioned material components utilize a composite antioxidant, comprised of a hindered amine light stabilizer (HALS) and a phosphite antioxidant. This composite antioxidant inactivates free radicals by providing hydrogen atoms, blocking chain reactions and neutralizing early free radicals. It also catalyzes the decomposition of ROOH (hydroperoxides), an intermediate product of decomposition and oxidation, into stable alcohols, preventing the generation of new free radicals upon thermal or photocatalytic decomposition. This achieves a dynamic, synergistic, closed-loop protection system, where free radical capture reduces new peroxide formation while peroxide decomposition eliminates the source of free radical regeneration. This dual mechanism of free radical capture and peroxide decomposition inhibits photooxidative aging. Compared to existing materials that rely on a single anti-aging mechanism, this dual action allows for greater adaptability to more complex environments (such as high-intensity UV and high temperatures), extending the material's outdoor life.

[0035] 3. Optimize the vulcanization system. Use di-tert-butyl peroxide isopropyl benzene (curing agent BIBP) and trimethylolpropane trimethacrylate (TMPTMA) for co-vulcanization. When heated to a certain temperature, di-tert-butyl peroxide isopropyl benzene (BIBP) undergoes homolysis to generate two highly active tert-butyloxy free radicals. The free radicals will preferentially attack the weak points in the rubber molecular chain, capture hydrogen atoms to generate macromolecular free radicals, and two adjacent macromolecular free radicals combine to form CC cross-linking bonds. Trimethylolpropane trimethacrylate (TMPTMA) contains three The highly reactive methacrylate double bond can participate in multiple cross-linking reactions at the same time. The free radicals generated by BIBP preferentially attack the double bonds of TMPTMA (which are more reactive than the rubber main chain) to generate stable TMPTMA free radicals. The TMPTMA free radicals combine with the rubber chain through the double bond, which can reduce the direct attack of the free radicals on the rubber main chain and reduce the probability of β-fracture. In this way, the synergistic vulcanization of peroxide and cross-linking agent can be achieved, which can increase the cross-linking density, enhance the network uniformity and stability, and make the stress distribution more uniform when the material is stretched, reducing stress concentration points.

[0036] The following tests are conducted on some key physical properties of the materials produced by using three different dosages of the surface-modified nano-silica (other components are fixed), as follows:

[0037] Performance indicators Test standards Surface modified nano-silica 15phr Surface modified nano-silica 20phr Surface modified nano-silica 25phr Hardness (Shore A) GB / T 531-1999 45±2 55±2 65±2 Specific gravity (g / cm³) GB / T 533-1991 1.02 1.08 1.12 Wear resistance (mm³) GB / T 1689-1998 80 65 75 Tensile strength (MPa) GB / T 528-1998 10 11 9 Elongation (%) GB / T 528-1998 350 280 250 Tear strength (kN / m) GB / T 529-1998 20 25 23

[0038] In the above test, the wear resistance is tested using the Akron abrasion test, and the smaller the value, the better the wear resistance. In addition, in the ozone resistance test, the conditions are an ozone concentration of 50pphm, a temperature of 40°C, a stretching rate of 20%, and a duration of 72 hours. The cracking criterion is that the surface crack length is ≤1mm to be qualified. By comparing the physical property test data of the above three different dosages, it can be seen that in terms of reinforcement effect and mechanical properties, when the dosage of surface modified nano-silica increases from 15phr to 20phr, the tensile strength increases by 26% (6.5→8.2 MPa), the tear strength increases by 25% (20→25 kN / m), and the wear resistance increases by 18.75% (80→65 mm³). When the dosage increases to 25phr, the tensile strength and tear strength decrease due to filler agglomeration, the elongation decreases significantly (350→250%), and the material brittleness increases. In terms of ozone resistance, a 20phr dosage of surface-modified nanosilica achieves optimal cross-linking network density, resulting in no cracks under ozone erosion. At 25phr, microcracks develop due to localized stress concentration. Comparative testing indicates that a dosage of 18-22phr of surface-modified nanosilica offers optimal overall physical properties, with 20phr being the most optimal, achieving a balance of high mechanical properties, wear resistance, and resistance to environmental aging.

[0039] The following table is a comparison table of the composition ratios of the invention material and two similar (traditional) components, as well as a comparison table of the multi-material tests with better comprehensive physical properties obtained from the trial production of each group.

[0040] Comparison table of the composition ratio of the invention material and two similar compositions:

[0041] Components The composition ratio of the present invention (phr) Comparative group 1 (phr) Comparative group 2 (phr) Butadiene rubber BR1208 28-38 30-35 30-35 Polybutadiene rubber JSR810 33-42 35-40 35-40 Surface modified nanosilica 15-25 none 15-25 Composite anti-aging agent (HALS+phosphite) 1-3 1-3 none Peroxide (BIBP) 1.5-2 1.5-2 1.5-2 TMPTMA 1-1.5 1-1.5 1-1.5

[0042] Comparison table of the best comprehensive physical properties of the multi-material tests obtained in the above trial production groups:

[0043] Test items Test standards <![CDATA[Original formula (including SiO2 + anti-aging agent)]]> <![CDATA[Control Group 1 (without SiO2)]]> Control group 2 (no anti-aging agent) DIN wear resistance (mm³) J62 80 180 90 Tensile strength (MPa) J57C method 12 8 12 Elongation at break (%) J57C method 400 600 380 Density (g / cm³) J60A method 1.15 1.05 1.15 Color fastness to light Method B J52B UV lamp, three hours continuous 3 3 4 Color fastness to light C method J52C spotlight 0.5m, 72 hours continuous 3 3 4 Aging resistance J53A method 70℃ 95%RH 72h No frost and no cracks Slight cracking Surface microcracks Hardness (Shore A) J56 Shaw A method 65 55 65 Right angle tearing (N / mm) J63 without cutting 55 35 50 Bending resistance J61 does not cut No cracks Slight cracks Surface microcracks

[0044] It can be seen from the above table that the physical properties of the material produced by using the material components of the present invention are better than those of the material produced by using the traditional two-material composition ratio.

[0045] The following discloses a production process for injecting transparent rubber suitable for the application of the above-mentioned component materials. The specific production process steps are as follows:

[0046] In the first step, the weighed butadiene rubber BR1208 and polybutadiene rubber JSR810 are mixed in a mixer for 90-100 seconds at a temperature of 100-110°C.

[0047] The second step is to pour the additive into the internal mixer that has completed the first step, and pour in 1 / 2 of the surface-modified nano-silica, and mix for 60-70 seconds at a temperature of 110-115°C;

[0048] The third step is to pour the remaining 1 / 2 of the surface modified nano-silica into the internal mixer that has completed the second step, and mix for 60-70 seconds at a temperature of 115-120°C.

[0049] Step 4: After completing step 3, the internal mixer continues to mix at 120-125°C for 120-140 seconds;

[0050] Step 5: After completing step 4, obtain the plasticized transparent material from the internal mixer, pour the transparent material into the turbine and continue to plasticize for at least 190 seconds, then take it out and granulate it to obtain a granular transparent material;

[0051] Step 6: Pour the granular transparent material into the hopper of the injection molding machine. Vulcanization temperature is 155±10℃, pressure is 155±5KG / cm2, and vulcanization time is set according to the quality of the product.

[0052] The above-mentioned method and steps are different from the traditional transparent rubber production process through step adjustment and parameter setting. The method and steps and parameter setting of the present invention are more conducive to improving the quality of the product.

[0053] The material component combination and production process disclosed in the present invention have material properties that are significantly superior to traditional rubber. It is a rubber that can achieve good fluidity and can significantly improve production efficiency and increase material utilization. When applied to shoe production, it can enhance product appearance, has a better anti-cracking effect, and can improve problems such as traditional rubber flash and excessive anti-prediction.

[0054] The above embodiments do not limit the product form and style of the present invention. Any appropriate changes or modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present invention.

Claims

1. An injection-molded anti-cracking transparent rubber, comprising a main material and an auxiliary agent, characterized in that: The main ingredients include butadiene rubber, polybutadiene rubber and surface-modified nano-silicon dioxide.

2. The anti-cracking transparent rubber according to claim 1, characterized in that: The butadiene rubber is of model BR1208, and / or the polybutadiene rubber is of model JSR810, and / or the surface-modified nano-silica has a particle size of 10-20 nm.

3. The anti-cracking transparent rubber according to claim 1, characterized in that: The auxiliary agent includes a composite anti-aging agent, a peroxide and / or a co-crosslinking agent.

4. The anti-cracking transparent rubber according to claim 3, characterized in that: The composite anti-aging agent is a composite anti-aging agent composed of a light stabilizer and a phosphite, and / or the peroxide is a co-vulcanizing agent, and / or the co-crosslinking agent is trimethylolpropane trimethacrylate.

5. The anti-cracking transparent rubber according to claim 1 or 4, characterized in that: The butadiene rubber accounts for 28-38 parts of the total weight, the polybutadiene rubber accounts for 33-42 parts of the total weight, and the surface-modified nano-silica accounts for 15-25 parts of the total weight.

6. The anti-cracking transparent rubber according to claim 5, characterized in that: The surface modified nano-silica accounts for 18-22 parts of the total weight.

7. The anti-cracking transparent rubber according to claim 6, characterized in that: The surface modified nano-silica accounts for 20 parts of the total weight.

8. The anti-cracking transparent rubber according to claim 3 or 4, characterized in that: The auxiliary agent includes a composite anti-aging agent, a peroxide and a cross-linking agent, wherein the composite anti-aging agent accounts for 1-3 parts by weight, the peroxide accounts for 1.5-2 parts by weight, and the cross-linking agent accounts for 1-1.5 parts by weight.

9. The anti-cracking transparent rubber according to claim 3 or 4, characterized in that: The butadiene rubber accounts for 28-38 parts of the total weight, the polybutadiene rubber accounts for 33-42 parts of the total weight, the surface-modified nano-silica accounts for 15-25 parts of the total weight, and the auxiliary agents include a composite anti-aging agent, a peroxide and a cross-linking agent, wherein the composite anti-aging agent accounts for 1-3 parts of the total weight, the peroxide accounts for 1.5-2 parts of the total weight, and the cross-linking agent accounts for 1-1.5 parts of the total weight.

10. A production process for injection molding crack-resistant transparent rubber according to any one of claims 1 to 9, wherein the production process comprises the following steps: In the first step, the weighed butadiene rubber BR1208 and polybutadiene rubber JSR810 are mixed in a mixer for 90-100 seconds at a temperature of 100-110°C. The second step is to pour the additive into the internal mixer that has completed the first step, and pour in 1 / 2 of the surface-modified nano-silica, and mix for 60-70 seconds at a temperature of 110-115°C; The third step is to pour the remaining 1 / 2 of the surface modified nano-silica into the internal mixer that has completed the second step, and mix for 60-70 seconds at a temperature of 115-120°C. Step 4: After completing step 3, the internal mixer continues to mix at 120-125°C for 120-140 seconds; Step 5: After completing step 4, obtain the plasticized transparent material from the internal mixer, pour the transparent material into the turbine and continue to plasticize for at least 190 seconds, then take it out and granulate it to obtain a granular transparent material; Step 6: Pour the granular transparent material into the hopper of the injection molding machine. Vulcanization temperature is 155±10℃, pressure is 155±5KG / cm2, and vulcanization time is set according to the quality of the product.