A formula of automobile rubber sealing strip and its preparation process

Abstract

The invention relates to the technical field of automobile parts, and in particular to a formula of an automobile rubber sealing strip and a preparation process thereof. The formula comprises the following raw materials by weight: 80-100 parts of EPDM; 20-30 parts of polypropylene; 1-2.5 parts of a vulcanizer; 2-4 parts of an accelerator; 30-55 parts of a reinforcing agent; 10-27 parts of a filler; 6-8 parts of an activator; 10-20 parts of a softener; 5-13 parts of bamboo fiber; 1-3 parts of polyethylene glycol; 0.5-3 parts of a dispersant; 3-6 parts of a water absorbent; and 2-4 parts of a coupling agent. The automobile rubber sealing strip prepared by the invention has good comprehensive performance, in particular, has good tear resistance and antibacterial function.

Description

Technical Field

[0001] The invention relates to the technical field of automobile parts, and in particular to a formula of an automobile rubber sealing strip and a preparation process thereof. Background Art

[0002] Sealing is an important indicator to measure the quality of the whole vehicle. Sealing strips are key components to ensure the sealing performance of vehicles. They are mainly used to fill the gaps between the components of the vehicle. They have the functions of waterproofing, dustproofing, sound insulation, heat insulation, shock absorption and buffering, preventing mold and corrosion, and improving the airtightness of the space. Automobile sealing strips can be divided into rubber sealing strips and plastic sealing strips according to the material type. Among them, rubber sealing strips have good elasticity and low cost, and are currently the most widely used automobile sealing strips. Automobile rubber sealing strips are mainly used in doors, windows, bodies, seats, sunroofs, engine boxes and trunks.

[0003] Traditional automotive rubber sealing strips mainly focus on the design and improvement of sealing performance, aging resistance, wear resistance, extrusion performance, tensile strength, etc. In terms of mechanical strength, the strength of the rubber sealing strip in the length direction, such as tensile strength, elongation at break and other performance indicators, is improved and improved. However, in fact, the tear resistance of the sealing strip is also very important in ensuring the sealing effect and extending the service life. Tear resistance refers to the resistance of the sealing strip when it is subjected to tearing or cutting force. Good tear resistance means that the sealing strip can remain intact when subjected to a certain tearing force, and will not easily crack or break. In this way, the sealing strip can maintain a good overall structure, especially the transverse structure. When the sealing strip is subjected to tensile stress, the transverse cross-section can better maintain the integrity of the structure, and it is not easy to break, which promotes the improvement of longitudinal properties such as tensile strength. However, the tear resistance of the existing sealing strip is only slightly higher than the standard requirements. At present, with the complexity of the transverse cross-sectional structure of the sealing strip, the importance of the tear resistance of the sealing strip in the overall application has gradually become prominent. Therefore, through the design and improvement of the formula and process, improving the mechanical strength of the sealing strip, especially the tear resistance, has become one of the technical problems that technicians in this field must face.

[0004] In addition, the surface of the automotive sealing strip will accumulate dirt and breed many bacteria after long-term use. Although the general wet cloth cleaning can eliminate the dirt, it can not play a fundamental role in removing bacteria. The only solution is to dismantle and disinfect. However, once the sealing strip is laid, it is difficult to dismantle and wash it, and the current effective disinfection methods, such as high-temperature disinfection and ultraviolet disinfection, are all very harmful to rubber materials. Therefore, people have a very urgent need for automotive sealing strips with antibacterial and antibacterial functions. Especially in recent years, with the development of society, the process of high industrialization has brought great convenience to our living and life, but also caused inevitable harm to our living environment, caused great damage to human health, and people's environmental protection concept has been improved. The demand for products with good antibacterial and antibacterial functions has become increasingly strong. In the existing rubber sealing strips, silver ion antibacterial agents are often used to give rubber sealing strips certain antibacterial and antibacterial properties, such as the technical solutions disclosed in the patents with public announcement numbers CN104448622A and CN103465837A. Silver ion antimicrobial agents have a strong bactericidal effect on a variety of bacteria, fungi and viruses. Their bactericidal effect has the advantages of strong antibacterial and broad spectrum. However, the addition of silver ion antimicrobial agents will have an adverse effect on the durability and mechanical properties of rubber materials, and the cost of silver ion antimicrobial agents is usually high. Most importantly, silver ion antimicrobial agents have obvious mobility, and the silver ions in them can be gradually released from the surface of the material to which they are applied or move to the surrounding environment, resulting in the attenuation of the antibacterial effect of silver ions.

[0005] If it is possible to provide an automotive rubber sealing strip with good comprehensive properties, especially good tear resistance and antibacterial functions, it will be of great benefit to promoting the development of enterprises and the advancement of rubber sealing strip technology.

[0006] On this basis, considering that bamboo grows fast, has low density, high strength, good flexibility and is not easy to break, the substances such as bamboo Kun it contains have good antibacterial and antibacterial properties and are recognized as green and environmentally friendly materials. If bamboo resources can be used for rubber sealing strips to improve and enhance the performance of rubber sealing strips, it will not only make full use of the abundant resources of bamboo, but also create new environmentally friendly rubber sealing strip products with more value and competitiveness, which will have a positive impact on both the environment and the economy. Summary of the invention

[0007] The purpose of the present invention is to provide a formula and preparation process of an automotive rubber sealing strip in order to solve the above-mentioned technical problems, so as to obtain an automotive rubber sealing strip with good comprehensive performance, especially with good tear resistance and antibacterial function.

[0008] In view of this, the present invention provides a formula for an automobile rubber sealing strip, which comprises the following raw materials in parts by weight:

[0009] EPDM 80~100 parts;

[0010] Polypropylene 20-30 parts;

[0011] 1~2.5 parts of vulcanizing agent;

[0012] 2~4 parts of accelerator;

[0013] 30~55 parts of reinforcing agent;

[0014] Filler 10~27 parts;

[0015] 6~8 parts of activator;

[0016] Softener 10~20 parts;

[0017] 5-13 parts of bamboo fiber;

[0018] 1-3 parts of polyethylene glycol;

[0019] Dispersant 0.5~3 parts;

[0020] 3~6 parts of water absorbent;

[0021] 2~4 parts of coupling agent.

[0022] Furthermore, the ethylene content in the EPDM is 50-58wt%, the third monomer is ENB, the iodine value is 8-20g iodine / 100g rubber, and the Mooney viscosity ML (1+4, 125°C) is 60-80.

[0023] Furthermore, the vulcanizing agent is sulfur, the accelerator is a mixture of DM and an ultra-speed accelerator, in which the mass percentage of DM is 30-50%; the balance is an ultra-speed accelerator, and the ultra-speed accelerator is selected from one or more of EZ, BZ, and PZ.

[0024] Furthermore, the reinforcing agent includes 60-70 wt % of carbon black and 30-40 wt % of modified bamboo charcoal powder.

[0025] Furthermore, the filler includes 70-90wt% of light calcium carbonate and 10-30wt% of modified bamboo powder, wherein the particle size of the light calcium carbonate is ≤1um; the modified bamboo powder is a powdery substance obtained by modifying the powdery substance produced during the physical crushing process of bamboo such as cutting, crushing, rolling, and grinding, and its particle size is less than or equal to 200nm.

[0026] Furthermore, the softener comprises, by weight, 8 to 10 parts of paraffin oil and 3 to 5 parts of bamboo oil.

[0027] Further, the preparation process of the softener is as follows:

[0028] a1, preparing bamboo oil: cutting bamboo, washing it with water, and air-drying it, and then pre-drying the bamboo at a temperature of 120-160°C for 30-60 minutes; then drying the bamboo at 300-400°C, collecting the volatile gas, and obtaining bamboo oil by condensing and separating the collected gas;

[0029] a2, preparing a softener: mixing various raw material components for preparing the softener according to a weight ratio, stirring evenly, to obtain the softener.

[0030] Furthermore, the preparation process of the reinforcing agent is as follows:

[0031] b1, pretreatment of de-oiled bamboo: take the bamboo treated in step a1 above, soak it in an alkaline solution, rinse it with water, dry it and set it aside;

[0032] b2, preparing bamboo charcoal powder: placing the bamboo treated in step b1 in a carbonization furnace, carbonizing at 500-800°C in an oxygen-deficient environment, then activating the carbonized bamboo, drying it, and grinding it to an average particle size of 0.1-1 um to obtain bamboo charcoal powder;

[0033] b3, bamboo charcoal powder modification treatment: placing the bamboo charcoal powder obtained in step b2 in a fluidized bed, using an inert gas as an operating gas, and filling the fluidized bed with an organic gas, and carbonizing the organic gas at 500-700° C., and forming particles that adhere to the surface of the bamboo charcoal powder to obtain the modified bamboo charcoal powder;

[0034] b4, preparing a reinforcing agent: uniformly mixing the modified bamboo charcoal powder and carbon black according to a weight ratio to obtain the reinforcing agent.

[0035] Furthermore, the preparation process of the bamboo fiber is as follows:

[0036] c1, crushing and screening: cutting bamboo, dry grinding and breaking into fiber powder with a length of ≤3cm, and then screening the fiber powder with a 300-400 mesh sieve, and the sieved material is coarse bamboo powder;

[0037] c2, high-pressure cooking: add an appropriate amount of cooking liquid to the high-pressure cooking container, and place the bamboo material on the sieve after screening in c1 on the steaming net in the high-pressure cooking container, heat the cooking liquid in the high-pressure cooking container to make it boil, pressurize the high-pressure cooking container, and perform a high-pressure cooking on the bamboo material at a pressure of 0.5-1MPa for 60-100min; after the high-pressure cooking is completed, cool it to below 50°C, atomize and spray the degumming agent solution onto the bamboo material, fill it with air and pressurize it to 2-3MPa, maintain the pressure for 10-20min, then quickly release the pressure and quickly reduce the pressure in the high-pressure cooking container to 0.5MPa; then heat it again, perform a second high-pressure cooking on the bamboo material at a pressure of 0.5-1MPa for 40-80min, reduce the pressure and temperature to normal temperature and pressure after the second high-pressure cooking, and take out the bamboo material;

[0038] c3. Post-treatment of bamboo fiber: dilute the bamboo material after high-pressure steaming in c2 with water to a bamboo material mass percentage of 8-15%, then send the mixed system into a pulping machine for debonding for 20-50 minutes, then dilute with water to a bamboo material mass percentage of 3-5%, and grind the diluted pulp to obtain a pulp with a beating degree of 41-52°SR;

[0039] c4. Cleaning and drying of bamboo fibers: The slurry obtained in c3 is filtered, washed with water, and dried to obtain the bamboo fibers.

[0040] A method for preparing an automobile rubber sealing strip, wherein the automobile rubber sealing strip is prepared according to the above formula, and the preparation method comprises the steps of:

[0041] S1, ingredients: weigh the raw materials for preparing the automotive rubber sealing strip according to the weight ratio;

[0042] S2, internal mixing: EPDM, polypropylene, softener and polyethylene glycol are added to an internal mixer and plasticized for 5-10 minutes at a plasticizing temperature of 110-120°C; then reinforcing agent, activator, filler, vulcanizing agent, accelerator, coupling agent, dispersant, water absorbent and bamboo fiber are added, and mixed in the internal mixer for 3-5 minutes until the mixture is uniform, at a mixing temperature of 120-130°C, and after cooling to 30-50°C, a mixed rubber is obtained;

[0043] S3, vulcanization and extrusion molding: the mixed rubber obtained in step S2 is vulcanized at a temperature of 270-290°C and a pressure of 20-25 MPa for 4-7 minutes, and then the vulcanized rubber is made into granules, which are dried at 50-60°C for 20-30 minutes and then extruded to obtain a rubber sealing strip.

[0044] The beneficial effects of the present invention are that the prepared automobile rubber sealing strip has good comprehensive performance, especially good tear resistance and antibacterial function. DETAILED DESCRIPTION

[0045] The technical solutions in this application will be described clearly below in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of this application, rather than all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in this application belong to the scope of protection of this application.

[0046] In the description of the present application, it should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. The techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the techniques, methods and devices should be considered as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0047] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0048] It should be noted that, in the present application, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises one..." does not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be noted that the scope of the method and device in the embodiment of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0049] A formula for an automobile rubber sealing strip, comprising the following raw materials in parts by weight:

[0050] EPDM 80~100 parts;

[0051] Polypropylene 20-30 parts;

[0052] 1~2.5 parts of vulcanizing agent;

[0053] 2~4 parts of accelerator;

[0054] 30~55 parts of reinforcing agent;

[0055] Filler 10~27 parts;

[0056] 6~8 parts of activator;

[0057] Softener 10~20 parts;

[0058] 5-13 parts of bamboo fiber;

[0059] 1-3 parts of polyethylene glycol;

[0060] Dispersant 0.5~3 parts;

[0061] 3~6 parts of water absorbent;

[0062] 2~4 parts of coupling agent.

[0063] Preferably, the ethylene content in the EPDM (ethylene propylene diene monomer rubber) is 50-58 wt %, the third monomer is ENB, the iodine value is 8-20 g iodine / 100 g rubber, and the Mooney viscosity ML (1+4, 125° C.) is 60-80.

[0064] Different grades of EPDM rubber have great differences in performance. The present invention selects EPDM with a higher ethylene content, which has high raw rubber strength, strong plasticity, good weather resistance, good ozone resistance, high extrusion performance, fast extrusion speed, and smooth extrusion surface. However, when the ethylene content is higher than 60%, the ethylene chain segment is prone to crystallization and the processability of the rubber compound deteriorates. Therefore, the ethylene content in EPDM is preferably 50-58wt%.

[0065] In addition, Mooney viscosity reflects the molecular weight of rubber and the magnitude of the intermolecular cohesive force. The present invention selects EPDM with a larger Mooney viscosity value, which can increase the crosslinking density and mechanical strength of the vulcanized rubber, improve the rebound performance, and have greater filling properties.

[0066] As some examples of the present invention, the vulcanizing agent is selected from one or more of sulfur, peroxide, quinone compounds, amine compounds, resin compounds, metal oxides, and the like.

[0067] Preferably, the vulcanizing agent is sulfur.

[0068] Although the above-mentioned various substances can be used as vulcanizing agents for EPDM rubber, compared with other vulcanizers, the cost of using sulfur to vulcanize EPDM rubber is low, the vulcanization time is short, and the product has good heat tear resistance. Therefore, the present invention selects sulfur as the vulcanizing agent for EPDM rubber.

[0069] As some examples of the present invention, the accelerator is selected from one or more of CZ, PZ, BZ, EZ, TRA, TMTD, TMTM, and DM.

[0070] Preferably, the accelerator is a mixture of DM and an ultra-speed accelerator, in which the mass percentage of DM is 30-50%; the balance is an ultra-speed accelerator, and the ultra-speed accelerator is selected from one or more of EZ, BZ, and PZ.

[0071] In the present invention, the low-sulfur and high-accelerator system can prevent sulfur blooming. At the same time, by using multiple accelerators in combination and utilizing the synergistic effect between different accelerators, the mixed system has a suitable vulcanization speed and crosslinking density.

[0072] Furthermore, the reinforcing agent is a mixture of carbon black and modified bamboo charcoal powder.

[0073] Preferably, the reinforcing agent comprises 60-70 wt % of carbon black and 30-40 wt % of modified bamboo charcoal powder.

[0074] Furthermore, the filler is selected from inorganic powders such as light calcium carbonate, talcum powder, clay, silica sand, titanium oxide, silicon dioxide, aluminum hydroxide, or organic powders such as starch, bamboo powder and polystyrene powder.

[0075] Preferably, the filler comprises 70-90wt% of light calcium carbonate and 10-30wt% of modified bamboo powder, wherein the particle size of the light calcium carbonate is ≤1um; the modified bamboo powder is a powdery substance obtained by modifying the powdery substance produced during the physical crushing process of bamboo such as cutting, crushing, rolling and grinding, and its particle size is less than or equal to 200nm.

[0076] Furthermore, the activator includes zinc oxide and stearic acid, wherein the mass ratio of zinc oxide to stearic acid is (3~8):1.

[0077] Furthermore, the softener is a mixture of paraffin oil and bamboo oil.

[0078] Preferably, the softener comprises, by weight, 8 to 10 parts of paraffin oil and 3 to 5 parts of bamboo oil.

[0079] More preferably, the kinematic viscosity (40°C) of the paraffin oil is 80-150 mm 2 / s, flash point ≥235℃.

[0080] Furthermore, the preparation process of the softener is as follows:

[0081] a1, preparing bamboo oil: cutting bamboo, washing it with water, and air-drying it, and then pre-drying the bamboo at a temperature of 120-160°C for 30-60 minutes; then drying the bamboo at 300-400°C, collecting the volatile gas, and obtaining bamboo oil by condensing and separating the collected gas;

[0082] a2, preparing a softener: mixing various raw material components for preparing the softener according to a weight ratio, stirring evenly, to obtain the softener.

[0083] Specifically, in step a1, after the collected gas is condensed, the obtained mixed liquid is left to stand and stratify, and the upper layer of liquid after stratification is bamboo oil. In addition, during the drying process, when the volatile gas condenses and no obvious droplets fall, the drying process ends.

[0084] As some examples of the present invention, in the step a1, the bamboo oil obtained by the liquid separation treatment may be filtered, dried, etc. to improve the cleanliness of the bamboo oil.

[0085] Bamboo oil contains more fatty acids, glycerides and other oil components, and its volatile component content is low, and it has good stability and durability. At the same time, the viscosity of bamboo oil is usually higher than that of other vegetable oils. In the softener described in the present invention, by adding a certain amount of bamboo oil, the adverse effects of paraffin oil on the tensile strength, tear strength and other properties of the vulcanized product can be improved, so that the tensile strength, elongation, tear strength and other properties of the vulcanized product are maintained at a better level; at the same time, the durability and stability of the vulcanized product can be improved.

[0086] Furthermore, the preparation process of the reinforcing agent is as follows:

[0087] b1, pretreatment of de-oiled bamboo: take the bamboo treated in step a1 above, soak it in an alkaline solution, rinse it with water, dry it and set it aside;

[0088] b2, preparing bamboo charcoal powder: placing the bamboo treated in step b1 in a carbonization furnace, carbonizing at 500-800°C in an oxygen-deficient environment, then activating the carbonized bamboo, drying it, and grinding it to an average particle size of 0.1-1 um to obtain bamboo charcoal powder;

[0089] b3, bamboo charcoal powder modification treatment: placing the bamboo charcoal powder obtained in step b2 in a fluidized bed, using an inert gas as an operating gas, and filling the fluidized bed with an organic gas, and carbonizing the organic gas at 500-700° C., and forming particles that adhere to the surface of the bamboo charcoal powder to obtain the modified bamboo charcoal powder;

[0090] b4, preparing a reinforcing agent: uniformly mixing the modified bamboo charcoal powder and carbon black according to a weight ratio to obtain the reinforcing agent.

[0091] Specifically, in the step b1, the alkaline solution is a NaOH solution with a concentration of 3-10 wt %, the temperature of the alkaline solution is 25-40° C., and the soaking time is 30-60 min.

[0092] As some examples of the present invention, in step b1, the bamboo soaked in the alkaline solution can be soaked and rinsed with clean water for 3 to 5 times to fully dissolve the alkaline solution remaining in the bamboo, and then the bamboo is dried for later use.

[0093] As some examples of the present invention, in step b2, the carbonized bamboo can be activated by soaking in a KOH solution for 3 to 5 hours.

[0094] As some examples of the present invention, in step b3, the organic gas is selected from one or more of benzene, xylene, and ethyl benzene, and the added amount of the organic gas is 20-30% of the weight of the bamboo charcoal powder.

[0095] Furthermore, the preparation process of the bamboo fiber is as follows:

[0096] c1, crushing and screening: cutting bamboo, dry grinding and breaking into fiber powder with a length of ≤3cm, and then screening the fiber powder with a 300-400 mesh sieve, and the sieved material is coarse bamboo powder;

[0097] c2, high-pressure cooking: add an appropriate amount of cooking liquid to the high-pressure cooking container, and place the bamboo material on the sieve after screening in c1 on the steaming net in the high-pressure cooking container, heat the cooking liquid in the high-pressure cooking container to make it boil, pressurize the high-pressure cooking container, and perform a high-pressure cooking on the bamboo material at a pressure of 0.5-1MPa for 60-100min; after the high-pressure cooking is completed, cool it to below 50°C, atomize and spray the degumming agent solution onto the bamboo material, fill it with air and pressurize it to 2-3MPa, maintain the pressure for 10-20min, then quickly release the pressure and quickly reduce the pressure in the high-pressure cooking container to about 0.5MPa; then heat it again, perform a second high-pressure cooking on the bamboo material at a pressure of 0.5-1MPa for 40-80min, reduce the pressure and temperature to normal temperature and pressure after the second high-pressure cooking, and take out the bamboo material;

[0098] c3. Post-treatment of bamboo fiber: dilute the bamboo material after high-pressure steaming in c2 with water to a bamboo material mass percentage of 8-15%, then send the mixed system into a pulping machine for debonding for 20-50 minutes, then dilute with water to a bamboo material mass percentage of 3-5%, and grind the diluted pulp to obtain a pulp with a beating degree of 41-52°SR;

[0099] c4. Cleaning and drying of bamboo fibers: The slurry obtained in c3 is filtered, washed with water, and dried to obtain the bamboo fibers.

[0100] Furthermore, in the step c2, the cooking liquid for high pressure cooking is an alkaline solution with a concentration of 10-20 wt%, such as KOH or NaOH solution, and the amount of cooking liquid added is 4-7 times the absolute dry weight of the screened material after screening.

[0101] Furthermore, in step c2, the degumming agent solution is an aqueous solution of ligninase, which contains 20-40 wt% of ligninase, and the amount of the degumming agent solution is 25-35% of the absolute dry weight of the sieve after sieving.

[0102] Furthermore, in the step c2, after the degumming agent solution is introduced and the pressure is maintained for a set time, the pressure in the high-pressure cooking container needs to be quickly reduced to about 0.5 MPa within 1 to 3 minutes.

[0103] Furthermore, the preparation process of the modified bamboo powder for filler is as follows:

[0104] d1, obtaining crude bamboo powder: taking the crude bamboo powder obtained in step c1 above and setting aside;

[0105] d2, crude bamboo powder pretreatment: add water to the crude bamboo powder obtained in d1 to prepare a dispersion with a crude bamboo powder content of 20-50 wt%, and use an alkaline solution to adjust the pH value of the dispersion to 7-9, then add 0.3-0.8% of the total weight of the crude bamboo powder amylase, and then heat the dispersion to 25-35° C., keep warm and stir for 20-30 minutes;

[0106] d3, modification of crude bamboo powder: adding water to the dispersion obtained in d2 to prepare a dispersion with a crude bamboo powder content of 10-20wt%, then adding nano-silicon dioxide accounting for 10-20% of the total weight of the crude bamboo powder, mixing evenly and grinding for 30-60 minutes, then adding nano-silicon dioxide accounting for 5-10% of the mass of the crude bamboo powder to the dispersion of crude bamboo powder again, mixing evenly, grinding the dispersion of crude bamboo powder for a second time, grinding for 40-80 minutes, centrifuging the dispersion of crude bamboo powder, washing to obtain a solid, and then drying to obtain modified bamboo powder.

[0107] In the present invention, by modifying the crude bamboo powder, the particle size of the bamboo powder can be reduced, and the bonding ability of the bamboo powder with the silane coupling agent and the dispersibility of the bamboo powder in the rubber can be improved.

[0108] Furthermore, the modified bamboo powder and light calcium carbonate are uniformly mixed according to a weight ratio to obtain the filler.

[0109] As some examples of the present invention, the dispersant is selected from one or more of WB16, ZnSA, FC-303, and stearic acid monoglyceride.

[0110] Preferably, the water absorbent is calcium oxide, and the average particle size of the calcium oxide is ≤1 um.

[0111] Preferably, the coupling agent is a silane coupling agent.

[0112] A preparation process for an automobile rubber sealing strip, wherein the preparation process adopts the above-mentioned formula of the automobile rubber sealing strip to prepare the automobile rubber sealing strip, and the preparation process comprises the steps of:

[0113] S1, ingredients: weigh the raw materials for preparing the automotive rubber sealing strip according to the weight ratio;

[0114] S2, internal mixing: EPDM, polypropylene, softener and polyethylene glycol are added to an internal mixer and plasticized for 5-10 minutes at a plasticizing temperature of 110-120°C; then reinforcing agent, activator, filler, vulcanizing agent, accelerator, coupling agent, dispersant, water absorbent and bamboo fiber are added, and mixed in the internal mixer for 3-5 minutes until the mixture is uniform, at a mixing temperature of 120-130°C, and after cooling to 30-50°C, a mixed rubber is obtained;

[0115] S3, vulcanization and extrusion molding: the mixed rubber obtained in step S2 is vulcanized at a temperature of 270-290°C and a pressure of 20-25 MPa for 4-7 minutes, and then the vulcanized rubber is made into granules, which are dried at 50-60°C for 20-30 minutes and then extruded to obtain a rubber sealing strip.

[0116] The following is an example of the formula and preparation method of the automotive rubber sealing strip described in the present invention:

[0117] Example 1

[0118] Preparation of softener

[0119] Softener 1 includes 9 parts of paraffin oil and 4 parts of bamboo oil;

[0120] Softener 2 includes 8 parts of paraffin oil and 5 parts of bamboo oil;

[0121] Softener 3 includes 10 parts of paraffin oil and 3 parts of bamboo oil;

[0122] The preparation process of the softener is as follows:

[0123] a1, preparing bamboo oil: cutting bamboo, washing it with water, and air-drying it, and then pre-drying it at a temperature of 130° C. for 40 minutes; then drying the bamboo at 380° C., collecting the volatile gas, and obtaining bamboo oil by condensing and separating the collected gas;

[0124] a2, preparing a softener: mixing paraffin oil and bamboo oil according to a weight ratio, stirring evenly, to obtain the softener 1, softener 2 and softener 3.

[0125] Example 2

[0126] Preparation of reinforcing agent:

[0127] Reinforcing agent 1 includes 64 wt % of carbon black and 36 wt % of modified bamboo charcoal powder;

[0128] Reinforcing agent 2 includes 60wt% carbon black and 40wt% modified bamboo charcoal powder;

[0129] Reinforcing agent 3 includes 70wt% carbon black and 30wt% modified bamboo charcoal powder;

[0130] b1, pretreatment of de-oiled bamboo: take the bamboo treated in step a1 of the above embodiment 1, soak it in an alkaline solution, rinse it with water, dry it and set it aside;

[0131] b2, preparing bamboo charcoal powder: placing the bamboo treated in step b1 in a carbonization furnace, carbonizing at 600°C in an oxygen-deficient environment, then activating the carbonized bamboo, drying it, and grinding it to an average particle size of 0.35 um to obtain bamboo charcoal powder;

[0132] b3, bamboo charcoal powder modification treatment: placing the bamboo charcoal powder obtained in step b2 in a fluidized bed, using an inert gas as an operating gas, and filling the fluidized bed with an organic gas, and carbonizing the organic gas at 620° C., and forming particles that adhere to the surface of the bamboo charcoal powder to obtain the modified bamboo charcoal powder;

[0133] b4, preparing a reinforcing agent: uniformly mixing the modified bamboo charcoal powder and carbon black according to a weight ratio to obtain reinforcing agent 1, reinforcing agent 2 and reinforcing agent 3.

[0134] Example 3

[0135] Preparation of bamboo fiber

[0136] c1, crushing and screening: cutting bamboo, dry grinding and breaking into fiber powder with a length of ≤3cm, and then screening the fiber powder with a 300-mesh sieve, and the sieved material is coarse bamboo powder;

[0137] c2, high-pressure cooking: add a proper amount of cooking liquid to the high-pressure cooking container, and place the bamboo material on the sieve after screening in c1 on the steaming net in the high-pressure cooking container, heat the cooking liquid in the high-pressure cooking container to make it boil, pressurize the high-pressure cooking container, and perform a high-pressure cooking on the bamboo material at a pressure of 0.8MPa for 80min; after the completion of the high-pressure cooking, cool it to below 50°C, atomize and spray the degumming agent solution onto the bamboo material, fill it with air and pressurize it to 2MPa, maintain the pressure for 18min, then quickly release the pressure and quickly reduce the pressure in the high-pressure cooking container to 0.5MPa; then heat it again, perform a second high-pressure cooking on the bamboo material at a pressure of 0.5MPa for 40min, reduce the pressure and temperature to normal temperature and pressure after the second high-pressure cooking, and take out the bamboo material;

[0138] c3. Post-treatment of bamboo fiber: dilute the bamboo material after high-pressure steaming in c2 with water to a bamboo material mass percentage of 10%, then send the mixed system into a pulping machine for debonding for 30 minutes, then dilute with water to a bamboo material mass percentage of 3%, and grind the diluted pulp to obtain a pulp with a beating degree of 46°SR;

[0139] c4. Cleaning and drying of bamboo fibers: The slurry obtained in c3 is filtered, washed with water, and dried to obtain the bamboo fibers.

[0140] Example 4

[0141] Preparation of fillers

[0142] Filler 1 includes 80 wt % of light calcium carbonate and 20 wt % of modified bamboo powder;

[0143] Filler 2 includes 70 wt % of light calcium carbonate and 30 wt % of modified bamboo powder;

[0144] Filler 3 includes 90 wt % of light calcium carbonate and 10 wt % of modified bamboo powder;

[0145] d1, obtaining crude bamboo powder: taking the crude bamboo powder obtained in step c1 of the above embodiment 3 and setting aside;

[0146] d2, crude bamboo powder pretreatment: the crude bamboo powder obtained in d1 is added with water to prepare a dispersion liquid with a crude bamboo powder content of 50 wt%, and the pH value of the dispersion liquid is adjusted to 8 with an alkaline solution, and then 0.6% of the total weight of the crude bamboo powder is added with amylase, and then the dispersion liquid is heated to 35° C., kept warm and stirred for 20 minutes;

[0147] d3, modification of crude bamboo powder: add water to the dispersion obtained in d2 to prepare a dispersion with a crude bamboo powder content of 13wt%, then add nano-silicon dioxide accounting for 20% of the total weight of the crude bamboo powder, mix well and grind for 60 minutes, then add nano-silicon dioxide accounting for 5% of the mass of the crude bamboo powder to the dispersion of crude bamboo powder again, mix well, and grind the dispersion of crude bamboo powder for the second time. After grinding for 40 minutes, the dispersion of crude bamboo powder is centrifuged and washed to obtain a solid, which is then dried to obtain modified bamboo powder.

[0148] Then, the modified bamboo powder and light calcium carbonate are uniformly mixed according to a weight ratio to obtain filler 1, filler 2 and filler 3.

[0149] Embodiments 5 to 10

[0150] Preparation of automotive rubber sealing strips

[0151] S1, ingredients: weigh the raw materials for preparing the automotive rubber sealing strip according to the formula shown in Table 1 below;

[0152] S2, internal mixing: EPDM, polypropylene, softener and polyethylene glycol are added to an internal mixer and plasticized for 8 minutes at a plasticizing temperature of 120°C; then reinforcing agent, activator, filler, vulcanizing agent, accelerator, coupling agent, dispersant, water absorbent and bamboo fiber are added and mixed in the internal mixer for 3 minutes until the mixture is uniform, at a mixing temperature of 120°C, and after cooling to 30°C, a mixed rubber is obtained;

[0153] S3, vulcanization and extrusion molding: the mixed rubber obtained in step S2 is vulcanized at a temperature of 270° C. and a pressure of 25 MPa for 5 minutes, and then the vulcanized rubber is made into granules, which are dried at 50° C. for 25 minutes and then extruded to obtain a rubber sealing strip.

[0154] Table 1 Raw material ratio of automotive rubber sealing strips

[0155]

[0156] Among them, the vulcanizing agents used in Examples 5 to 10 are all sulfur;

[0157] The accelerators used in Examples 5 to 10 are: 40wt% DM + 60% PZ, 40wt% DM + 60% BZ, 40wt% DM + 60% EZ, 30wt% DM + 30% PZ + 40% BZ, 30wt% DM + 30% PZ + 40% EZ, 50wt% DM + 30% PZ + 20% BZ;

[0158] The reinforcing agents used in Examples 5 to 10 are, in order: reinforcing agent 1, reinforcing agent 1, reinforcing agent 2, reinforcing agent 2, reinforcing agent 3, reinforcing agent 3 prepared in Example 2 above;

[0159] The fillers used in Examples 5 to 10 are, in order: filler 1, filler 1, filler 2, filler 2, filler 3, filler 3 prepared in Example 4 above;

[0160] The activator used in Examples 5 to 10 is a mixture of zinc oxide and stearic acid in a mass ratio of 3:1, 4:1, 5:1, 6:1, 7:1 and 8:1, respectively;

[0161] The softeners used in Examples 5 to 10 are, in order: softener 1, softener 1, softener 2, softener 2, softener 3, softener 3 prepared in Example 1 above;

[0162] The bamboo fiber used in Examples 5 to 10 is the bamboo fiber prepared in Example 3 above;

[0163] The dispersants used in Examples 5 to 10 are: WB16, WB16, WB16, FC-303, FC-303, FC-303;

[0164] The water absorbing agent used in Examples 5 to 10 is nano calcium oxide;

[0165] The coupling agent used in Examples 5 to 10 is a silane coupling agent.

[0166] Comparative Example 1 Preparation of Automobile Rubber Sealing Strip

[0167] The difference between it and the above-mentioned Example 8 is that the reinforcing agent used in Comparative Example 1 is pure carbon black;

[0168] Comparative Example 2 Preparation of Automobile Rubber Sealing Strip

[0169] The difference between it and the above-mentioned Example 8 is that the reinforcing agent used in Comparative Example 2 is a mixture of carbon black and bamboo charcoal powder obtained in step b2 of Example 2;

[0170] Comparative Example 3 Preparation of Automobile Rubber Sealing Strip

[0171] The difference between it and the above-mentioned Example 8 is that the reinforcing agent used in Comparative Example 3 is carbon black and modified bamboo charcoal powder prepared from bamboo from which bamboo oil has not been extracted. The preparation process of the modified bamboo charcoal powder is: directly cutting the original bamboo from which bamboo oil has not been extracted through step a1 in Example 1, and preparing it according to steps b1 to b4 in Example 2;

[0172] Comparative Example 4 Preparation of Automobile Rubber Sealing Strip

[0173] The difference between it and the above-mentioned Example 8 is that the filler used in Comparative Example 4 is pure light calcium carbonate;

[0174] Comparative Example 5 Preparation of Automobile Rubber Sealing Strip

[0175] The difference between it and the above-mentioned Example 8 is that the filler used in the comparative example 5 is a mixture of light calcium carbonate and bamboo powder, wherein the bamboo powder is not modified, and the preparation process of the bamboo powder is: according to the steps d1 to d3 in the above-mentioned Example 4, wherein in the implementation process of d3, nano silicon dioxide is not added, and only dilution, grinding and centrifugation are performed;

[0176] Comparative Example 6 Preparation of Automobile Rubber Sealing Strip

[0177] The difference between it and the above-mentioned Example 8 is that the softener used in Comparative Example 6 is pure paraffin oil;

[0178] Comparative Example 7 Preparation of Automobile Rubber Sealing Strip

[0179] The difference between it and the above-mentioned Example 8 is that the bamboo fiber used in Example 7 is not treated with separating crude bamboo powder. In the process of preparing bamboo fiber, all the fiber powder crushed in step c1 is placed in a high-pressure cooking container and treated according to steps c2 to c4 in Example 3.

[0180] Performance Testing

[0181] The properties of the automotive rubber sealing strips prepared in the above Examples 5 to 10 and Comparative Examples 1 to 7 were tested, and the results are shown in Table 2 below:

[0182] Table 2 Performance test results of automotive rubber sealing strips

[0183]

[0184] The embodiments of the present application are described above in combination with Table 1 and Table 2. In the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A formula for an automotive rubber sealing strip, characterized in that: Including raw materials by weight: EPDM 80~100 parts; Polypropylene 20-30 parts; 1~2.5 parts of vulcanizing agent; 2~4 parts of accelerator; 30~55 parts of reinforcing agent; Filler 10~27 parts; 6~8 parts of activator; Softener 10~20 parts; 5-13 parts of bamboo fiber; 1-3 parts of polyethylene glycol; Dispersant 0.5~3 parts; 3~6 parts of water absorbent; 2~4 parts of coupling agent; Wherein, the softener comprises, by weight: 8 to 10 parts of paraffin oil and 3 to 5 parts of bamboo oil; The preparation process of the softener is as follows: a1, preparing bamboo oil: cutting bamboo, washing it with water, and air-drying it, and then pre-drying the bamboo at a temperature of 120-160°C for 30-60 minutes; then drying the bamboo at 300-400°C, collecting the volatile gas, and obtaining bamboo oil by condensing and separating the collected gas; a2, preparing a softener: mixing the raw material components for preparing the softener according to a weight ratio, stirring evenly, to obtain the softener; The reinforcing agent comprises 60-70wt% of carbon black and 30-40wt% of modified bamboo charcoal powder; The preparation process of the reinforcing agent is as follows: b1, pretreatment of de-oiled bamboo: take the bamboo treated in step a1 above, soak it in an alkaline solution, rinse it with water, dry it and set it aside; b2, preparing bamboo charcoal powder: placing the bamboo treated in step b1 in a carbonization furnace, carbonizing at 500-800°C in an oxygen-deficient environment, then activating the carbonized bamboo, drying it, and grinding it to an average particle size of 0.1-1 um to obtain bamboo charcoal powder; b3, bamboo charcoal powder modification treatment: placing the bamboo charcoal powder obtained in step b2 in a fluidized bed, using an inert gas as an operating gas, and filling the fluidized bed with an organic gas, and carbonizing the organic gas at 500-700° C., and forming particles that adhere to the surface of the bamboo charcoal powder to obtain the modified bamboo charcoal powder; b4, preparing a reinforcing agent: uniformly mixing the modified bamboo charcoal powder and carbon black according to a weight ratio to obtain the reinforcing agent; In step b3, the organic gas is selected from one or more of benzene, xylene, and ethylbenzene, and the amount of the organic gas added is 20-30% of the weight of the bamboo charcoal powder; The preparation process of the bamboo fiber is as follows: c1, crushing and screening: cutting bamboo, dry grinding and breaking into fiber powder with a length of ≤3cm, and then screening the fiber powder with a 300-400 mesh sieve, and the sieved material is coarse bamboo powder; c2, high-pressure cooking: add an appropriate amount of cooking liquid to the high-pressure cooking container, and place the bamboo material on the sieve after screening in c1 on the steaming net in the high-pressure cooking container, heat the cooking liquid in the high-pressure cooking container to make it boil, pressurize the high-pressure cooking container, and perform a high-pressure cooking on the bamboo material at a pressure of 0.5-1MPa for 60-100min; after the high-pressure cooking is completed, cool it to below 50°C, atomize and spray the degumming agent solution onto the bamboo material, fill it with air and pressurize it to 2-3MPa, maintain the pressure for 10-20min, then quickly release the pressure and quickly reduce the pressure in the high-pressure cooking container to 0.5MPa; then heat it again, perform a second high-pressure cooking on the bamboo material at a pressure of 0.5-1MPa for 40-80min, reduce the pressure and temperature to normal temperature and pressure after the second high-pressure cooking, and take out the bamboo material; c3. Post-treatment of bamboo fiber: dilute the bamboo material after high-pressure steaming in c2 with water to a bamboo material mass percentage of 8-15%, then send the mixed system into a pulping machine for debonding for 20-50 minutes, then dilute with water to a bamboo material mass percentage of 3-5%, and grind the diluted pulp to obtain a pulp with a beating degree of 41-52°SR; c4. Cleaning and drying of bamboo fiber: filtering, washing and drying the slurry obtained in c3 to obtain the bamboo fiber; The filler comprises 70-90 wt% of light calcium carbonate and 10-30 wt% of modified bamboo powder. The preparation process of the modified bamboo powder for filler is as follows: d1, obtaining crude bamboo powder: taking the crude bamboo powder obtained in step c1 above and setting aside; d2, crude bamboo powder pretreatment: add water to the crude bamboo powder obtained in d1 to prepare a dispersion with a crude bamboo powder content of 20-50 wt%, and use an alkaline solution to adjust the pH value of the dispersion to 7-9, then add 0.3-0.8% of the total weight of the crude bamboo powder amylase, and then heat the dispersion to 25-35° C., keep warm and stir for 20-30 minutes; d3, crude bamboo powder modification treatment: adding water to the dispersion obtained in d2 to prepare a dispersion with a crude bamboo powder content of 10-20wt%, then adding nano-silicon dioxide accounting for 10-20% of the total weight of the crude bamboo powder, mixing evenly and grinding for 30-60min, then adding nano-silicon dioxide accounting for 5-10% of the mass of the crude bamboo powder to the crude bamboo powder dispersion again, mixing evenly, and grinding the crude bamboo powder dispersion for a second time. After grinding for 40-80min, the crude bamboo powder dispersion is centrifuged and washed to obtain a solid, and then dried to obtain modified bamboo powder; Then, the modified bamboo powder and light calcium carbonate are uniformly mixed according to a weight ratio to obtain the filler.

2. The formula of the automotive rubber sealing strip according to claim 1, characterized in that: The EPDM has an ethylene content of 50-58 wt %, the third monomer is ENB, the iodine value is 8-20 g iodine / 100 g rubber, and the Mooney viscosity ML (1+4, 125° C.) is 60-80.

3. The formula of the automotive rubber sealing strip according to claim 1, characterized in that: The vulcanizing agent is sulfur, and the accelerator is a mixture of DM and an ultra-speed accelerator. In the accelerator, the mass percentage of DM is 30-50%; the balance is an ultra-speed accelerator, and the ultra-speed accelerator is selected from one or more of EZ, BZ, and PZ.

4. The formula of the automotive rubber sealing strip according to claim 1, characterized in that: The particle size of the light calcium carbonate is ≤1um; the particle size of the modified bamboo powder is less than or equal to 200nm.

5. A method for preparing an automobile rubber sealing strip, characterized in that: The preparation method is to prepare an automotive rubber sealing strip according to the formula described in any one of claims 1 to 4, and the preparation method comprises the steps of: S1, ingredients: weigh the raw materials for preparing the automotive rubber sealing strip according to the weight ratio; S2, internal mixing: EPDM, polypropylene, softener and polyethylene glycol are added to an internal mixer and plasticized for 5-10 minutes at a plasticizing temperature of 110-120°C; then reinforcing agent, activator, filler, vulcanizing agent, accelerator, coupling agent, dispersant, water absorbent and bamboo fiber are added, and mixed in the internal mixer for 3-5 minutes until the mixture is uniform, at a mixing temperature of 120-130°C, and after cooling to 30-50°C, a mixed rubber is obtained; S3, vulcanization and extrusion molding: the mixed rubber obtained in step S2 is vulcanized at a temperature of 270-290°C and a pressure of 20-25 MPa for 4-7 minutes, and then the vulcanized rubber is made into granules, which are dried at 50-60°C for 20-30 minutes and then extruded to obtain a rubber sealing strip.

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