CN115139433A

CN115139433A - Gum micro powder using rubber product as raw material and preparation and application thereof

Info

Publication number: CN115139433A
Application number: CN202210661199.7A
Authority: CN
Inventors: 高玉海; 冯民堂; 曹焕苹; 傅懿军
Original assignee: Qingdao Xinju Road Resources Technology Co ltd
Current assignee: Qingdao Xinju Road Resources Technology Co ltd
Priority date: 2022-06-13
Filing date: 2022-06-13
Publication date: 2022-10-04

Abstract

The invention discloses a rubber micro powder taking a rubber product as a raw material, and preparation and application thereof. The preparation method comprises the following steps: performing circular cutting on the tire, and cutting off tire bead rubber on two sides; performing water jet crushing on the tire tread and the tire shoulder; the rubber after the primary crushing is subjected to mechanical flocculation treatment at low temperature, and then pre-freezing and cryogenic embrittlement are sequentially performed; the rubber after cryogenic embrittlement enters a crushing bin to be ground and crushed, the crushed materials are automatically classified, the materials which do not reach the fineness requirement return to the pre-cooling bin, and the materials which reach the fineness requirement enter a finished product bin. The glue micro powder is convenient to prepare and easy to industrially produce, and the preparation method of the glue micro powder is industrially verified, so that the glue micro powder can be recycled to an original product for new product manufacturing and application instead of a new glue level according to a proportion of 25-100%, and meanwhile, the problem of black pollution and environmental protection caused by waste rubber products is thoroughly solved, and the glue micro powder is an important technical breakthrough in the industry that waste rubber resources can be industrially recycled in a large scale and the value is preserved and the level is recycled.

Description

Gum micro powder using rubber product as raw material and preparation and application thereof

Technical Field

The invention relates to the technical field of functional and organic polymer resin composite elastomer materials, in particular to a rubber micro powder taking a rubber product as a raw material, and preparation and application thereof.

Background

Taking a waste tire in a waste rubber product as an example, the tire tread and the sidewall rubber of the tire are composed of a unit body similar to a core-shell structure, and the core-shell structure is an ordered assembly structure formed by coating one material with the other material through chemical bonds or other acting forces; the diameter distribution of the rubber powder is about 50-500nm, and the core-shell structure units are tightly combined together through means such as vulcanization treatment, so that the waste rubber products are recycled to prepare rubber powder, the finer the rubber powder particles are, the better the dispersity is, and experiments prove that important processing indexes such as surface activity, tensile strength and elongation at break gradually approach to new rubber as the waste rubber particles become smaller and smaller.

The pollution of rubber products mainly comprising waste tires is generally called black pollution, and the black pollution becomes a difficult problem to be solved in the world along with the development of industries such as automobiles and the like; at present, four main modes of global recycling of waste rubber products are available: 1) Producing reclaimed rubber; 2) Renovating; 3) Producing rubber powder by a traditional process; 4) And (4) thermal cracking.

1) Producing reclaimed rubber: at present, most countries are forbidden due to serious secondary pollution problems;

2) Renovating: the use times and the time length of the tires can be prolonged by retreading rubber products such as the tires, but the problem of waste rubber circulation terminal cannot be fundamentally solved;

3) The rubber powder is produced by the traditional process:

(1) the traditional mechanical method is characterized in that the rubber powder has thicker particles, poor mechanical property, high energy consumption and low efficiency, the average particle size is difficult to industrially break through 120 meshes, the rubber particles have low surface activity of sheet or block, the rubber powder with the total crushing amount of not more than 15 percent and the D50 of 75 micrometers (200 meshes) can be obtained even by a screening method, similar rubber powder can be only blended and used or degraded for low-end products in a very low proportion, the economic benefit is extremely low, and the conditions of the self-circulation magnitude and the quality of waste rubber products in a rubber product system can not be met;

(2) although the traditional liquid nitrogen or compressed air turbine refrigeration low-temperature crushing method is simple in process principle, the investment is large, the energy consumption is extremely high, the production efficiency is extremely low, the processing cost is high, meanwhile, the particle size of the product is difficult to break through 200 meshes in a large scale, the application range of the rubber powder is narrow, the cost of the rubber powder product is close to or higher than the market price, and the professional enterprises cannot operate continuously.

4) Thermal cracking: the thermal cracking is basically anti-scientific and anti-economic, namely, a long-chain elastomer substance with high added value is cracked into low-value micromolecule products with dozens of carbon chains through high energy consumption, the only effect is to consume waste rubber products, and industrial enterprises cannot continuously operate due to the reasons of high treatment energy consumption, difficulty in process control, low production efficiency, low product quality and the like under the condition of no other extra income.

Disclosure of Invention

The invention aims to provide a rubber micro powder taking a rubber product as a raw material, and preparation and application thereof. The glue micro powder is convenient to prepare and easy to industrially produce, and the preparation method of the glue micro powder is industrially verified, so that the glue micro powder can be recycled to an original product for new product manufacturing and application instead of a new glue level according to a proportion of 25-100%, and meanwhile, the problem of black pollution and environmental protection caused by waste rubber products is thoroughly solved, and the glue micro powder is an important technical breakthrough in the industry that waste rubber resources can be industrially recycled in a large scale and the value is preserved and the level is recycled.

The glue micro powder prepared by the invention has the following advantages: the rubber micro powder has ultrahigh surface activity, extremely small average particle size and narrow particle size distribution, and retains the physicochemical indexes of the original rubber, such as tensile strength, elongation at break and the like.

The main material of the rubber product in the invention is one or any combination of natural rubber, styrene butadiene rubber, polybutadiene rubber, butyl rubber, butadiene rubber, other elastomers and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a preparation method of rubber micropowder by taking a rubber product as a raw material, which comprises the following steps:

cutting the rubber product to be recycled, and removing the non-recycled part;

conveying the cut recyclable rubber into a water jet crushing bin through a conveying device for primary crushing; specifically, under the strong impact action of high-pressure water jet which moves in a reciprocating manner in the crushing bin, the size range of primary crushing is achieved;

carrying out mechanical flocculation treatment on the rubber subjected to preliminary crushing at low temperature; specifically, the rubber particles after primary crushing are subjected to mechanical flocculation treatment at low temperature by using the mechanical action of shearing, grinding and stretching, so that the treatment of the subsequent process is facilitated;

the rubber after flocculation treatment sequentially enters a pre-cooling bin and a freezing bin for pre-cooling and deep cooling embrittlement; specifically, rubber after flocculation treatment enters a precooling bin through a conveying device, stays for a period of time at a precooling temperature, then enters a freezing bin, and is cooled to a set copious cooling temperature within a set copious cooling time, so that the internal structure of the rubber is embrittled;

the rubber after cryogenic embrittlement enters a crushing bin to be ground and crushed according to a set particle size range program, the crushed materials are automatically classified, few materials which do not reach the fineness requirement return to a pre-cooling bin, and the materials which reach the fineness requirement enter a finished product bin.

When the rubber product to be recycled is a tire, performing circular cutting on the tire by using a circular cutting machine, and cutting off tire side rubber on two sides; and conveying the ring-cut tire tread and tire shoulder into a water jet crushing bin through a conveying device, and separating and primarily crushing rubber and steel wires. Specifically, under the strong impact action of the high-pressure water jet which moves in a reciprocating mode in the crushing bin, rubber of tire shoulders and tire treads is separated from steel wires, and the size range of primary crushing is achieved.

The circular cutting is to cut off the tire sidewall rubber and realize the classified recycling of different parts; the water jet crushing is to separate the tire tread, the tire shoulder, the steel wire framework and the fiber layer, under the strong impact of high-pressure water jet, cracks on the tire gradually expand to form a section, the tire shoulder and the tire tread are crushed into small blocks, and the steel wire framework and the fiber layer are completely stripped; the mechanical flocculation treatment at low temperature is to generate stress action areas on the surface and the inside of the rubber block by the mechanical action force at low temperature, improve the surface and the internal structure of the rubber, and promote crack propagation and flocculation; precooling and deep cooling are used for making the interior of the rubber completely brittle and convenient for crushing. Only high-pressure water jet is used for crushing, the processing efficiency is low, the obtained rubber powder is irregular in shape, the rubber main chain is easily damaged excessively, and the mechanical property is influenced; the steel wires and fibers in rubber products cannot be effectively removed only by cryogenic low-temperature crushing or mechanical chopping for deepening the cryogenic low-temperature crushing, the steel wire residues and short fibers cannot be effectively separated when being mixed with rubber powder, the dispersity of the rubber powder is influenced when the rubber powder is used, and further the strength of the rubber powder is reduced and the application field is narrowed.

According to the preparation method of the invention, preferably, the number of the high-pressure water jet nozzles in the water jet crushing bin is 2-30, and the diameter is 1.5-3.5 mm; the strength of the water jet is 340MPa to 480MPa, the target distance (the distance from the nozzle to the material) is 30mm to 100mm, and the moving speed is 500mm/min to 1500mm/min.

When the high-pressure water jet is broken, it is not preferable that the nozzle diameter is smaller and the water pressure is higher. The higher the jet strength is, the higher the energy consumption is, the stronger the destructive power to the rubber is, and the stronger the stripping effect is, but when the jet strength exceeds a certain value, the steel wire framework can be cut off (the recovery value of the steel wire framework is influenced), and the carbon black aggregate can be stripped and damaged possibly, so that the mechanical property of the rubber powder is influenced; if the jet flow strength is not enough or the moving speed is too fast, the cutting depth is not enough, the steel wire framework can not be completely separated, and the rubber powder is flocculent and is difficult to be utilized. More preferably, the number of the high-pressure water jet nozzles is 10-20, the diameter of the nozzles is 2.3 mm-3 mm, the water jet strength is 340 MPa-430 MPa, the target distance is 45 mm-75 mm, and the moving speed is 750 mm/min-1200 mm/min.

According to the preparation method of the invention, preferably, the cabin body of the water jet crushing cabin has a diameter of 1.5-6 m and a thickness of 0.5-1.5 m, wherein the shaft is a variable support frame and can rotate within a certain speed range. More preferably, the cabin body of the water jet crushing cabin has the diameter of 2.5-4 meters and the thickness of 1-1.5 meters, wherein the shaft is a variable support frame and can rotate in a certain speed range.

According to the preparation method of the present invention, preferably, the size of the preliminary crushing ranges from 2cm to 10cm.

According to the preparation method of the invention, preferably, the low-temperature mechanical flocculation treatment specifically utilizes a fiber chopping machine to carry out two times of crushing treatment on the rubber block.

According to the preparation method of the invention, the temperature of the mechanical flocculation treatment at the low temperature is preferably-120 ℃ to-80 ℃.

The mechanical flocculation treatment at low temperature is to generate stress action areas on the surface and inside of the rubber block by mechanical acting force at low temperature, which is beneficial to crack propagation and improves the processing efficiency. The temperature is controlled to prevent rubber powder property change and timely heat dissipation caused by coking or adhesion due to heat generation of mechanical shearing.

According to the preparation method of the invention, preferably, the pre-freezing temperature is-60 ℃ to-30 ℃ and the time is 20s to 200s; the temperature of the cryogenic embrittlement is-196 ℃ to-80 ℃, and the time is 60s to 300s.

The stepped temperature of pre-cooling and deep cooling is set to fully utilize the refrigerant and save resources, and the pre-cooling is carried out while the materials are synchronously dried, so that the redundant moisture is pumped away and the particles are prevented from agglomerating.

According to the preparation method provided by the invention, the industrial single-line capacity of the preparation method is preferably not less than 220 kilograms per hour, and the annual capacity is not less than 2500 tons.

The invention also provides a rubber micro powder prepared from the rubber product, and the rubber micro powder is prepared by the preparation method.

The rubber micro powder is convenient to prepare and easy to industrially produce, has the characteristics of ultrahigh surface activity, good particle type regularity, narrow particle size distribution range and controllable particle size, is mainly distributed in submicron, is partially distributed in nanoscale, and simultaneously keeps and approaches the tensile strength and the original elongation at break of the original rubber product, and can be widely applied to the fields of original rubber product recycling, exterior wall heat-insulating coating, ship shell coating, noise-reducing and wave-absorbing material and the like.

According to the gum micro powder of the present invention, preferably, the surface activity of the gum micro powder is 1900KJ/mol to 2300KJ/mol.

According to the gum micro powder of the present invention, preferably, the gum micro powder has a diameter of 0.5 to 50 μm.

The invention also provides the application of the glue micro powder in a resin material with high toughness and high strength, or a resin material with high damping performance, shock absorption and noise reduction, or a resin material with waterproof, anticorrosion, high elasticity and high strength requirements, or a resin material with vulcanization precipitation and physical adsorption.

Specifically, the resin material with high toughness and high strength is a household automobile tire or a heavy truck tire, a large-load or large-inclination-angle conveying belt or a high-strength PU wood-plastic plate;

the resin material with high damping performance and shock absorption and noise reduction is a damping and noise reduction coating in the field of automobiles, high-speed ships or high-speed moving machinery, or a shock absorption base of a high-speed railway or a bridge;

the resin material with waterproof, anticorrosion, high elasticity and high strength requirements is a wide-temperature-range waterproof coating or a coiled material, a high-elasticity waterproof coating, a high-pressure waterproof plugging agent or a water stop belt;

the resin material with the functions of sulfide precipitation and physical adsorption is a metal impurity ion adsorbent or sulfide precipitator for water treatment.

The rubber micro powder is used in resin related materials with high damping performance, shock absorption and noise reduction, and the resin related materials with high damping performance, shock absorption and noise reduction are damping and noise reduction coatings in the fields of automobiles, high-speed ships, high-speed moving machinery and the like, and shock absorption bases of high-speed railways and bridges. The glue micro powder can be compounded with polymer resin and organic polymer resin and is used for preparing resin related materials with high damping performance and shock absorption and noise reduction. The proportion of the micro-powder and the organic polymer resin can be adjusted by those skilled in the art according to the needs, for example, when preparing the material related to the resin with high damping performance, shock absorption and noise reduction, the micro-powder can be uniformly mixed with the polymer resin, and the weight ratio (calculated by 100 parts of the total weight) of the micro-powder and the polymer resin can be N: (100-N), N =5, 6, 7 \8230: \8230, 28, 29, 30. The polymer resin can be various polymer resins suitable for high damping performance, shock absorption and noise reduction, and the polymer can be one or a combination of natural rubber, styrene-butadiene rubber, butyl rubber, nitrile rubber, polyvinyl acetate, polyurethane, chlorinated polyethylene, polyvinyl chloride, acrylic acid and asphalt.

The glue micro powder is used for organic resin water proofing and corrosion prevention or for preparing resin related materials with high elasticity and high strength, wherein the water proofing, corrosion prevention and high elasticity and high strength require that the resin related materials are wide-temperature-range waterproof coatings or coiled materials, high-elasticity waterproof coatings, high-pressure waterproof plugging agents and water stops. The glue micro powder can be compounded with organic polymer resin and used for preparing resin related materials with waterproof, anticorrosion, high elasticity and high strength requirements. The proportion of the gum micro powder compounded with the organic polymer resin can be adjusted by a person skilled in the art according to the needs, for example, when preparing a resin-related material with waterproof, anticorrosion, high elasticity and high strength requirements, the gum micro powder can be uniformly mixed with the polymer resin, and the weight ratio (calculated by 100 parts of the total weight) of the ultra-high activity submicron pure gum micro powder to the polymer resin can be N: (100-N), N =20, 21, 22 \8230; 38, 39, 40. The polymer resin can be any polymer resin suitable for high damping performance, shock absorption and noise reduction, and the polymer resin can be one or a combination of natural rubber, butadiene rubber, SBS, TPO, PET, TPV, polystyrene, PVC or polyurethane.

The glue micro powder is used in resin related materials required by sulfide precipitation and physical adsorption, and the resin related materials with sulfide precipitation and physical adsorption are a metal impurity ion adsorbent and a sulfide precipitator for water treatment. More preferably, the mercury-containing wastewater sulfurization precipitation adsorbent is used in the chlor-alkali industry and the gold beneficiation industry. The glue micro powder can be compounded with organic polymer resin and used for preparing resin related materials required by sulfide precipitation and physical adsorption. The proportion of the fine rubber powder to the organic polymer resin can be adjusted by those skilled in the art according to needs, for example, when preparing a material related to a resin required by vulcanization precipitation and physical adsorption, the fine rubber powder can be uniformly mixed with the polymer resin, and the weight ratio of the fine rubber powder to the polymer resin can be 2. The polymer resin can be any polymer resin suitable for vulcanization precipitation and physical adsorption, and can be one of polystyrene, polyacrylic acid, phenolic resin, epoxy resin and polyvinyl chloride or a combination thereof.

The preparation method of the ultra-high activity submicron pure rubber micropowder taking the rubber product as the raw material is suitable for treating various rubber products, covers new rubber and waste rubber, and is particularly suitable for treating various radial tires. Particularly, by utilizing the preparation method provided by the invention, the new rubber micropowder produced by taking new rubber as a raw material can better meet the requirements of application fields such as ultrathin rubber insulating coatings (coatings), high-end coatings, noise reduction and wave absorption materials and the like.

The submicron rubber particle prepared by adopting a physical means has good particle type regularity and does not contain any exogenous non-rubber impurities; narrow particle size distribution range, D ₅₀ The particle size of the rubber powder is adjustable between 10 and 30 mu m and is 1/6 to 1/10 of the particle size of other industrial rubber powder, namely the volume ratio is 1/216 to 1/1000; secondly, the surface activity of the glue micro powder prepared by the method is as high as 1950KJ/mol, which is 2 times of the common process level, and a material parameter basis is provided for the old glue to be recycled to the original product; the method provided by the invention has low consumption and high efficiency, the energy consumption is less than 60% of that of the general method, one-step forming is different from the existing screening process of the glue micro powder with 100-200 meshes, the annual capacity of the sample plate per production line can reach more than 2500 tons at present, and industrial replication can be carried out to realize large-scale production; compared with other methods for degrading and using waste rubber for milling or cracking oil refining and extracting carbon black by machinery, the method not only realizes comprehensive recycling of tires and steel wire frameworks and environmental-friendly and pollution-free treatment process, but also realizes equal-quantity substitution and use of waste rubber and new rubber, and the waste rubber is recycled after the level of the waste rubber is openedThe wide channel provides a choice for downstream rubber product enterprises to greatly reduce the production cost.

In the application aspect, the submicron rubber particles provided by the invention have high surface activity, tensile strength and tensile strength index because the particle size is fine and part of the submicron rubber particles is smaller than 1 micron, and can partially or completely replace new rubber when a rubber product is processed; the glue seeds such as natural glue have the following characteristics: self characteristics such as aging resistance, corrosion resistance, wave absorption, anaerobic inhibition of biological hanging and the like; the submicron-grade rubber micro powder (containing spherical rubber micro powder) has better effects in the aspects of being used as plastic rubber modification, heat insulation materials, damping noise elimination materials, wide-temperature-range waterproof coatings, ship coatings and the like; it can also be used as sulfide precipitant and metal ion adsorbent for water treatment.

Compared with the prior art, the ultra-high activity submicron grade pure gum micropowder taking (waste) rubber products as raw materials and the preparation method thereof provided by the invention have the following beneficial effects:

1) The obtained colloidal micro powder has fine particles, regular particle shape, good sphericity and narrow particle size distribution range.

2) The obtained rubber micro powder product has high surface activity which is nearly 100% higher than that of the prior common rubber powder (60-120 mesh rubber tire powder).

3) The obtained rubber micropowder has high tensile strength and elongation at break which are two times of those of reclaimed rubber, and are 40-50% higher than common rubber powder (60-120 mesh rubber tire powder), and the retention rate of physicochemical properties of the original new rubber reaches about 90%.

4) The obtained gum micropowder can be fully vulcanized for the second time and combined with new gum, and can replace new natural gum within the range of 30-100%.

5) The obtained glue micro powder can be made into pieces or lumps at normal temperature, so that dust pollution is prevented, and the transportation is convenient.

6) The preparation process is simple and convenient to operate, easy for industrial mass production, high in production efficiency and low in cost, and the uniformly distributed rubber micro powder with the D50 of 10-30 mu m can be obtained through single low-temperature crushing, so that the comprehensive recovery and high-value utilization of (waste) rubber products are realized.

7) When the preparation method provided by the invention is used, new rubber or a new rubber product is taken as a raw material, and the prepared new rubber micro powder can meet the requirements of high-end application fields such as ultrathin rubber insulating materials, high-end coatings, noise elimination/wave absorption materials and the like.

The ultra-high activity submicron pure rubber micropowder taking (waste) rubber products as raw materials provided by the invention can enhance the tensile strength, damping performance, elasticity and the like of products when being used as organic functional resin toughening and reinforcing materials, damping and shock absorbing materials and wide-temperature-range waterproof coatings, and has better use effect. The composite rubber particle of the rubber micropowder and the organic polymer resin has large specific surface area and high activation energy, and has wide prospect in the application of a vulcanization precipitator for water treatment and a metal ion adsorbent.

Drawings

Fig. 1 and fig. 2 are scanning electron micrographs and CPS disk centrifuge particle size analysis curves of the gum micropowder with D50=28.77 μm in example 1, respectively.

Detailed Description

In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.

The invention provides a super-high activity submicron grade pure rubber micro powder material which has simple preparation, lower cost, uniform particle size distribution, high activity and high mechanical property by taking (waste) rubber products as raw materials and adopting a physical processing mode, and the invention is completed on the basis.

The invention provides an ultra-high activity submicron pure gum micro powder material which takes (waste) rubber products as raw materials and has the advantages of low cost, controllable particle size, regular particle shape and excellent mechanical property, a preparation method and application thereof. The preparation process of the glue micro powder provided by the invention has the advantages of strong controllability, simple process, low cost, controllable particle size, narrow particle size distribution range, spherical or nearly spherical shape, high surface activity and easy compatibility with other high polymer materials, and when the glue micro powder is used as a main material or is compounded with organic high polymer resin, the obtained product has good elasticity, toughness, damping performance or adsorption performance, and has good application prospects in multiple technical fields. The rubber micro powder taking the (waste) rubber product as the raw material and the preparation method thereof provided by the invention realize the high value-added recycling of the (waste) rubber product, can effectively solve the problem of black pollution of the (waste) rubber product, especially rubber tires, and save a large amount of scarce rubber resources. When the preparation method provided by the invention is utilized and new rubber or a new rubber product is taken as a raw material, the prepared new rubber micro powder can meet the requirements of high-end application fields such as ultrathin rubber insulating materials, high-end coatings, noise elimination/wave absorption materials and the like, and the high value-added utilization of rubber resources is realized.

The following description of the embodiments of the present invention is provided by way of specific examples, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

It is to be understood that the process equipment or devices not specifically mentioned in the following examples are conventional in the art.

Furthermore, it is to be understood that one or more method steps recited in the present disclosure are not exclusive of other method steps that may also be present before or after the recited combination of steps or that other method steps may also be inserted between the explicitly recited steps, unless otherwise indicated; it is also to be understood that a combined connection between one or more devices/apparatus as referred to in the present application does not exclude that further devices/apparatus may be present before or after the combined device/apparatus or that further devices/apparatus may be interposed between two devices/apparatus explicitly referred to, unless otherwise indicated. Moreover, unless otherwise indicated, the numbering of the various method steps is merely a convenient tool for identifying the various method steps, and is not intended to limit the order in which the method steps are arranged or the scope of the invention in which the invention may be practiced, and changes or modifications in the relative relationship may be made without substantially changing the technical content.

Example 1

In the embodiment, the rubber micro powder is prepared by taking a rubber product (tire) as a raw material, and the method comprises the following steps:

and performing circular cutting on the tire by using a circular cutting machine, and cutting off the tire bead rubber at two sides.

And conveying the circularly cut tire tread and tire shoulder into a water jet crushing bin through a conveying device. In the crushing bin, the water jet parameters are set to be 2.5mm in nozzle diameter, the jet strength is 360MPa, the target distance is 55mm, the moving speed is 1200mm/min, and under the strong impact action of the reciprocating high-pressure water jet, rubber and steel wires of tire shoulders and tire treads are separated and are initially crushed to be about 3-8 cm.

The rubber after the primary crushing is subjected to mechanical flocculation treatment at the temperature of minus 80 ℃, and the shape and the size of small rubber blocks are reduced by utilizing the mechanical actions of shearing, grinding and stretching of a fiber chopping machine, so that the rubber blocks are convenient to treat in the subsequent process.

The pretreated rubber enters a pre-cooling bin through a conveying device, pre-cooling is carried out for 180s at minus 60 ℃, then the material enters a freezing bin, and the temperature is reduced to minus 120 ℃ in 240s, so that the internal structure of the rubber is embrittled.

And (3) crushing the cryogenic and brittle rubber in a crushing bin according to a crushing program with D50=30 μm, grading the crushed material by a grader, returning the material which does not meet the fineness requirement to the pre-cooling bin, and feeding the graded product into a finished product bin.

Fig. 1 and 2 are scanning electron micrographs of gum micropowder with D50=28.77 μm and CPS disc centrifuge particle size analysis curves in example 1, respectively.

As can be seen from FIG. 1, the particle size of the colloidal micropowder is regular, the particles are concentrated in the range of 20-30 μm, and the ultrafine particles are few.

The data points in the particle size analysis curve of fig. 2, after being processed by the analytical instrument, gave the results as given in tables 1 and 2 below:

TABLE 1

TABLE 2 cumulative particle size distribution data

The average particle size of the glue micro powder is about 28 mu m, the particle size distribution is uniform and is concentrated in an interval of 22-43 mu m, and the proportion of the maximum value and the minimum value of the particle size is low.

The surface activity of the gum micropowder was tested according to the test method provided in ISO 11358-2.

TABLE 3

According to the test data of the surface activity, the surface activity of the glue micro powder is higher and is superior to that of the current commercially available 120-mesh glue powder. When the rubber is applied to rubber products taking natural rubber as a main raw material, the bonding capacity of rubber powder and a natural rubber matrix can be obviously improved, molecular chain segments of the rubber powder and the natural rubber matrix can deeply and mutually permeate to form a good transition layer, and the co-vulcanization is realized, so that the integral comprehensive mechanical property is improved.

Example 2

The effect of the fine gum powder obtained in example 1 on the natural gum was tested.

According to the GB/T19208-2020 standard, the formula of the rubber compound is shown in the following table 4, wherein "rubber powder" represents the rubber micro powder prepared in example 1, "S" represents sulfur, "SA hard fat" represents stearic acid, and the materials in the formula are calculated in parts by weight.

TABLE 4 Experimental formulation

The compound rubber is vulcanized and sampled at 145 ℃ for 8min (10 MPa), and the mechanical property test results are shown in the following table 5:

TABLE 5 mechanical Properties

The test results in table 5 show that the tensile strength and elongation at break of the rubber micropowder prepared from the (waste) rubber product are far higher than those of the rubber micropowder prepared from the national standard (15 MPa and 450%), the stress at definite elongation is obviously enhanced, and the comprehensive mechanical properties are good. From the formulas 1 to 3, it can be known that the stress at definite elongation and the tear strength are gradually enhanced with the increase of the amount of the gum micro powder.

Example 3

High-strength V-belt production experiments were carried out with the gum micropowder obtained in example 1.

The formula 1 in the following table 6 is an original formula, 40% and 60% of the new rubber are respectively replaced by the rubber micro powder obtained in the example 1 in the formula 2 and the formula 3, the technical requirements of products can be met, and rubber resources are saved.

TABLE 6

Note: in table 6, NR indicates natural rubber, rubber powder is the fine rubber powder prepared in example 1, cis-butadiene rubber indicates cis-butadiene rubber, SA stearin indicates stearic acid, accelerators are thiazole accelerators M and DM, anti-aging agent is anti-aging agent BLE, plasticizer is paraffin, lubricant is nano magnesium silicate, and reinforcing agent is high abrasion resistance carbon black.

Table 7 below is the test data:

TABLE 7

Example 4

This example prepares an anti-slip vulcanized rubber shoe sole.

In the embodiment, the defective products in the production process of a shoe factory are used as raw materials, and the defective products are prepared into the glue micro powder according to the method of the invention for recycling, and the method comprises the following steps:

and cutting the defective product, and removing the vamp.

The rubber sole is sent into a water jet crushing bin through a conveying device. In the crushing bin, the water jet parameters are set to be 2.5mm of nozzle diameter, the jet strength is 360MPa, the target distance is 55mm, the moving speed is 1200mm/min, and rubber blocks of about 3cm are initially crushed under the strong impact action of the reciprocating high-pressure water jet.

The rubber blocks after the primary crushing are subjected to mechanical flocculation treatment at the temperature of minus 80 ℃, and the shape and the size of small rubber blocks are reduced by utilizing the mechanical actions of shearing, grinding and stretching of a fiber chopping machine, so that the treatment of the subsequent process is facilitated.

The rubber embrittled deeply enters a crushing bin to be crushed according to a crushing program with D50=30 μm, the crushed material is classified by a classifier, the material which does not meet the fineness requirement returns to a pre-cooling bin, and the classified product enters a finished product bin.

The gum micro powder is added for recycling according to the following formula 8, formula 1, and other processing conditions are unchanged. The inspection data of the finished product are shown in Table 9.

TABLE 8

TABLE 9

From the detection data of the table 9, the performance and the quality of the shoes are basically not affected after the defective soles are made into the rubber micropowder for recycling, a large amount of raw materials of nitrile rubber and ethylene propylene diene monomer can be saved, and the problem of treatment of defective products is solved.

In conclusion, the invention effectively overcomes various difficulties and disadvantages in the existing recovery of waste rubber products, has high industrialization value and environmental protection value, and the submicron-grade rubber micro powder or other elastomer micro powder prepared by using new rubber or other new elastomers shows a brand-new material characteristic due to the characteristics of particle size, surface activity and the like, can widely exert excellent values in the fields of recycling, material modification, rubber coatings, ultrathin insulating sheets, adsorbing materials and the like, and simultaneously provides a reliable method with low cost for disposing defective products in the rubber and elastomer product industry.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.

Claims

1. A preparation method of rubber micropowder by taking a rubber product as a raw material is characterized by comprising the following steps:

cutting the rubber product to be recycled, and removing the non-recycled part;

conveying the cut recyclable rubber into a water jet crushing bin through a conveying device for primary crushing;

the rubber after the preliminary crushing is subjected to mechanical flocculation treatment at low temperature;

the rubber subjected to flocculation treatment sequentially enters a pre-cooling bin and a freezing bin to be pre-frozen and subjected to cryogenic embrittlement;

the rubber after cryogenic embrittlement enters a crushing bin to be ground and crushed, the crushed materials are automatically classified, the materials which do not reach the fineness requirement return to the pre-cooling bin, and the materials which reach the fineness requirement enter a finished product bin.

2. The preparation method of claim 1, wherein the number of the high-pressure water jets in the water jet crushing bin is 2 to 30, and the diameter of the high-pressure water jets is 1.5mm to 3.5mm; the strength of the water jet is 340MPa to 480MPa, the target distance is 30mm to 100mm, and the moving speed is 500mm/min to 1500mm/min.

3. The preparation method of claim 1, wherein the cabin of the water jet crushing bin has a diameter of 1.5-6 m and a thickness of 0.5-1.5 m, and wherein the shaft is a variable support frame and is capable of rotating within a certain speed range.

4. The method of claim 1, wherein the size of the preliminary crushing is in a range of 2cm to 10cm.

5. The method according to claim 1, characterized in that the mechanical flocculation treatment at low temperature is carried out by crushing the rubber block twice, in particular by means of a fiber chopper.

6. The process according to claim 1, characterized in that the temperature of the mechanical flocculation treatment at low temperature is between-120 ℃ and-80 ℃.

7. The preparation method according to claim 1, characterized in that the pre-freezing temperature is-60 ℃ to-30 ℃ and the time is 20s to 200s; the temperature of the cryogenic embrittlement is-196 ℃ to-80 ℃, and the time is 60s to 300s.

8. A gum micropowder made from a rubber product, characterized in that it is obtained by the production method according to any one of claims 1 to 7.

9. Micropowder according to claim 8, characterized in that the surface activity of the micropowder is 1900KJ/mol to 2300KJ/mol.

10. Micropowder according to claim 8, characterized in that the diameter of the micropowder is between 0.5 and 50 μm.

11. The application of the micro-powder of any one of claims 8 to 10 in resin materials with high toughness and high strength, or resin materials with high damping performance and shock absorption and noise reduction, or resin materials with waterproof, corrosion prevention, high elasticity and high strength requirements, or resin materials with sulfide precipitation and physical adsorption.

12. The use according to claim 11, wherein the resin material with high toughness and high strength is a household automobile tire or a heavy truck tire, a high-load or high-inclination conveyor belt, or a high-strength PU wood-plastic plate;

the resin material with high damping performance and shock absorption and noise reduction is a damping noise reduction coating in the field of automobiles, high-speed ships or high-speed moving machinery, or a shock absorption base of a high-speed railway or a bridge;