TWI492914B - Rubberized concrete made by using waste rubber tires and manufacturing method and system thereof - Google Patents

Description

Rubber concrete, manufacturing method and system using waste rubber tire

The present invention relates to a rubber concrete produced from a waste rubber tire, wherein the waste rubber tire system is subjected to surface treatment by catalytic partial oxidation by a metal oxide catalyst. The use of catalytically oxidized rubber particles compared to the use of non-catalytic oxidation-treated rubber particles has advantages including excellent mechanical strength and drainage capacity, lower oxidation temperature, shorter oxidation time, and accelerated hydration time. In catalytic oxidation, cooperatively produced rubber oil (a type of condensation gas), which acts as an adhesive, is comparable or superior to commercial high-performance plasticizers.

Since the accumulation of waste rubber tires is a major environmental problem, the recycling and utilization of waste tire rubber has become a subject that has been closely studied.

A modified asphalt cement composite as described in U.S. Patent Publication No. 20070249762 to Sylvester, wherein the rubber particles are desulfurized via catalysis of dodecylbenzenesulfonic acid (DBSA). At the same time, dodecylbenzenesulfonic acid (DBSA) also catalyzes the reaction between the particles of the desulfurized rubber asphalt and the molecules contained in the asphalt.

Rubber concrete is another application of rubber particles recovered from waste tires; however, when hydrophobic rubber particles are mixed with hydrophilic cement, the mechanical strength of the cement produced is greatly reduced.

U.S. Patent No. 5, 456, 751 to Zandi et al., U.S. Patent No. 5,762, 702 to Guy, and U.S. Patent Publication No. 20050096412 to Peter et al., concluded that mixed rubber particles and cement will be in rubber particles and cement matrix. The relatively weak physical bond is produced, which greatly reduces the mechanical properties of the rubber concrete, so that its use is severely limited.

Conventional rubber concrete uses high-efficiency plasticizers to improve the physical bonding of hydrophobic rubber particles and hydrophilic cement matrix so that rubber concrete composites can be used in selected applications.

In order to improve the mechanical properties of rubber concrete, several surface treatment methods have been developed to improve the tire rubber powder in order to produce stronger physical/chemical bonding or to produce a stronger chemical bond with the surrounding cement matrix.

Segre et al. disclose a sodium hydroxide treatment to improve the adhesion of tire rubber particles to cementitious agents, but the resulting rubber concrete is still 33% less compressive than conventional concrete. (See Segre's "Use of Tire Rubber Particles in Cement Paste", Cement and Concrete Research 2000, 30(9), pp. 1421 to 1425).

U.S. Patent No. 5,849,818 to Walls et al. discloses a process for sulfonating the outer layer of rubber particles with a sulfur trioxide-containing reaction gas. The rubber (polymer) particles are coated with a layer of sulfonate containing a high dose of a sulfonic acid or sulfonate moiety.

These sulfonated particles impart beneficial properties to the composite which are used as articles such as cement, organic resins, cellulosic plastics and the like in aggregates; in particular, the concrete may be made of Polish cement containing the above aggregates.

Partial oxidation of rubber particles from waste tires that are hazardous to the environment produces surface-treated rubber particles and a condensation gas that is used as a rubber concrete for improved mechanical strength compared to conventional rubber concrete. Mixing.

In general, partial oxidation changes the surface of the sulfur-containing rubber particles from hydrophobic to hydrophilic. The surface of the rubber treated with bismuth, arsine and organic sulfur trioxide functional groups (R-SO _x -R) will have a stronger interaction with the hydrophilic surface of the surrounding cement matrix and be used to improve the mechanical strength of rubber concrete. .

The hydrophilic, chemically stable rubber surface interacts strongly with the hydrophilic surface of the surrounding cement matrix. The co-produced condensation gas in the partial oxidation reactor mainly includes an active sulfur oxide (R-SO _x -R) as an excellent adhesive to further improve the joint strength when the partially oxidized rubber particles are mixed with the cement.

Rubber concrete with improved mechanical properties is better than conventional rubber concrete. However, the rate of the non-catalytic partial oxidation reaction is rather slow, and therefore, a high reaction temperature of 200 to 300 degrees and a long residence time of 45 to 120 minutes are required.

The present invention is based, in part, on the development of a partial oxidation technique for catalyzing metal oxides, which are surface treated at significantly lower temperatures and with substantially reduced processing time to enhance the surface properties of the rubber particles.

It has been confirmed that the particles of the catalytically partially oxidized modified rubber particles of the surrounding cement matrix exhibit a better adhesion than the particles of the non-catalyticly oxidized modified rubber particles.

The catalytic oxidation of the particle surface of the rubber particles is not only apparent at lower temperatures but also for a shorter period of time, and this process also produces more hydrophilic reactive functional groups on the rubber surface than with non-catalytic methods. The interaction of cement is more intense.

Preferred metal oxide catalysts include, for example, ferrous oxide (FeO) and ferric oxide (Fe ₂ O ₃ ). No other catalyst is required. Thus, partial oxidation can be catalyzed by one or more catalysts containing or substantially containing a suitable metal oxide.

In a preferred embodiment, the surface of partially oxidized rubber particles is analyzed by Fourier transform infrared spectroscopy (FT-IR) using ferrous oxide (FeO) or ferric oxide (Fe ₂ O ₃ ) as a catalyst. It is shown that in order to avoid excessive oxidation, the maximum value of the R-SO _x -R functional group is generated on the surface of the rubber particles, in an environment of about 150 degrees and 20 minutes and about 200 degrees and 30 minutes, respectively. Achieved under oxidizing conditions.

Industrial scale, continuous partial oxidation is preferred with horizontal tubular reactors equipped with a motor driven multi-blade horizontal mixer. The rubber particulate and catalyst mixed powder is delivered through the reactor at a controlled rate for the desired reaction time. The gaseous oxidation stream passes through the reaction zone simultaneously with the mixed powder.

Catalytic partial oxidation also produces a novel adhesive for rubber particles and cement matrix. When oxidizing the metal oxide, a small portion of the rubber particles are converted into rubber oil (which is in the form of a condensed gas) while leaving by-products. Some of the rubber oil stays in the oxidized rubber particles, making it slightly sticky.

This adhesive performance is comparable or superior to commercial high-performance plasticizers. Therefore, use reminders Rubber concrete made from partially oxidized rubber particles and residual adhesives do not require expensive commercial high-efficiency plasticizers.

Using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques, it has been proven that the production of rubber concrete using catalytically oxidized rubber particles is superior to non-catalytic oxidation of rubber. particle. From the FT-IR spectrum of the rubber oil, the R-SO _x -R functional group shows a stronger signal than the surface of the partially oxidized rubber particles.

This means that the rubber oil is mainly made of a group of short-chain R-SO _x -R (R-SO-R, R-SO ₂ -R, and R-SO ₃ ), which can greatly improve the partial oxidation rubber particles. And the bond strength between the cement substrates.

Whether it is compared to non-catalytic oxidized rubber and cement or untreated rubber and cement, the hydrated cement made by catalytic oxidation of rubber particles and cement has a surprising feature, namely its excellent moisture resistance.

The hydrophobic nature of the rubber concrete of the present invention makes it particularly suitable for roofing, bridge foundations, seawall construction and other marine applications.

1‧‧‧reactor vessel

2‧‧‧ screen

3‧‧‧heating ring

4‧‧‧ Controller

5‧‧‧fixed bed

6‧‧‧Intake pipe

7‧‧‧Exhaust pipe

8‧‧‧ valve

9‧‧‧ valve

10‧‧‧air source

11‧‧‧Nitrogen source

12‧‧‧ valve

13‧‧‧Valve

14‧‧‧ Container

20‧‧‧Reactor

21‧‧‧Preheater

22‧‧‧ Valve

23‧‧‧ pipeline

24‧‧‧ valve

25‧‧‧ pipeline

26‧‧‧ pipeline

27‧‧‧Valves

28‧‧‧ pipeline

29‧‧‧ pipeline

30‧‧‧ pipeline

31‧‧‧cooler

32‧‧‧ pipeline

42‧‧‧Auger

43‧‧‧Spiral blades

44‧‧‧Axis

Figure 1 is a schematic view of a continuous partial oxidation reactor; Figure 2 is a schematic view of an experimental batch partial oxidation reactor; Figures 3 and 4 are FT-IR spectra of the surface of an untreated rubber and a partially oxidized rubber, It is a schematic diagram of the catalyst with and without metal oxidation under different conditions; Figure 5 is a graph of FT-IR area ratio (S = O stretching area / Sp3 CH stretching area), which is relative to the partial oxidation temperature. a partially oxidized rubber which is a rubber formed by oxidizing ferrous oxide (FeO) and ferric oxide (Fe ₂ O ₃ ) at different oxidation times; FIG. 6 is a rubber produced by partial oxidation of rubber particles. The FT-IR spectrum of the oil is catalyzed by ferrous oxide (FeO) and ferric oxide (Fe ₂ O ₃ ) in an environment of 150 degrees 20 minutes and 200 degrees 30 minutes; Figure 7 and Figure 8 are water FT-IR spectrum of the cement; Figure 9-13 is the X-ray diffraction (XRD) spectrum of the hydrated cement; Figure 14 is the scanning electron microscopy (SEM) of the rubber concrete sample; and Figure 15 is the various hydration clay An image of the sample.

A cost-effective way to improve the mechanical properties of rubber concrete by using surface-treated rubber particles that form a stronger physical/chemical bond or a significantly stronger chemical bond with the surrounding cement matrix. Strong adhesion.

Through partial oxidation, the surface treatment involves converting a group of sulfide functional groups (-S-) to a sulfhydryl group (-SO ₂ ) or an anthracene group (-S=O) on the surface of the rubber particles.

The process changes the surface of the rubber particles from hydrophobic to hydrophilic, thereby effectively promoting the mixing of the modified rubber particles and the hydrophilic cement; in addition, the process converts the surface of the sulfide functional group (-S-) into more active. The sulfhydryl group (-SO ₂ ) and the fluorene group (-S=O) form a strong chemical bond with the surrounding cement matrix during hydration.

Under controlled conditions, organic sulfur compounds (RSR) can be oxidized to organic sulfonium (R-SO-R), organic hydrazine (R-SO ₂ -R) and organic trioxide (R-SO _x ). It can be oxidized to SO _x gases under excessive oxidation conditions.

In the rubber fine particles, 〝R〞 represents a rubber component to which a sulfur-containing functional group is bonded. The anthracene functional group (-S=O) is more active than the sulfhydryl group (-SO ₂ ), while the sulfhydryl group (-SO ₂ ) is more active than the sulfide group (-S-). For example, dimethylhydrazine is more chemically active than dimethylhydrazine and its activity is much higher than that of dimethyl sulfide.

In the present invention, the compressive strength, the flexural strength, and the tensile strength of the rubber concrete are enhanced by adding the partially oxidized rubber particles of the catalytic metal oxide and the co-generated condensation gas to the cement mixture.

Conventional concrete is a hardenable mixture composed of a cementitious material (or cement mix), fine aggregates such as sand, coarse aggregates, and water. The relative proportions in the composition of the concrete composite vary, depending on the desired properties of the cured product. See, for example, U.S. Patent No. 5,624,491 to Liske and et al., and U.S. Patent No. 5,456,751, issued to et al.

The concrete composite of the present invention generally contains from 0.1 to 20% by weight, preferably from 2 to 10% by weight, more preferably from 3.0 to 7.5% by weight of oxidized rubber particles. When added, the concrete composite generally contains at least 0.1% by weight, preferably 0.1% to 1.0% by weight, of a liquid adhesive (condensed gas).

Due to the addition of oxidized rubber particles, the proportion of coarse aggregate materials needs to be reduced. The superior mechanical properties of the rubber concrete of the present invention are exhibited by the use of the condensed gas, and the concrete composite material made of the partially oxidized rubber particles exhibits superior mechanical properties without using a high-efficiency plasticizer.

The mechanical strength of rubber concrete containing non-catalytic partial oxidized rubber of U.S. Patent Application Serial No. 13/078,913, the entire disclosure of which is incorporated herein by reference. a co-produced adhesive (condensed gas) which, after curing for about 50 days or more, will have (1) a compressive strength of at least 40 MPa, preferably a strength of 40 to 60 MPa; (2) a lexural strength of at least 5.4 MPa, preferably 5.4 MPa to 6.6 MPa; and (3) a tensile strength of at least 2.9 MPa, preferably 3.1 to 3.4. The intensity of megapascals. During this catalytic oxidation process, these properties should be further enhanced by the addition of co-produced additional added adhesives.

The present invention exhibits a stronger mechanical strength than ordinary concrete by adding catalytically oxidized rubber particles to the cement mixture, and only 7 days after the concrete is solidified.

This function was demonstrated by the greatly enhanced CSH signal in the FT-IR spectrum around the wavenumbers of 878, 670 and 1000 cm-1. It is shown to be mainly due to the increase in the formation of surface R-SO _x -R functional groups due to the catalytic oxidation of the rubber particles compared to the non-catalytic oxidation.

C ₃ S(3CaO‧SiO ₂ or Ca ₃ SiO ₅ ) and C ₂ S(2CaO‧SiO ₂ or Ca ₂ SiO ₃ ) are the main components of cement, forming CSH bonds during hydration, and these strong adhesions It is the basis of the mechanical properties of concrete. There is evidence that the addition of catalytic oxidized rubber particles to the cement slurry accelerates the hydration process of the rubber concrete.

The benefits of using catalytic oxidized rubber particles have been demonstrated in X-ray diffraction (XRD) analysis relative to the use of non-catalytic oxidized rubber particles to make rubber concrete.

In the XRD spectrum, C rubber concrete containing the catalytic oxidation of the rubber ₃ S / C ₂ S / CSH crystalline peak intensity to a rubber containing a non-catalytic oxidation of rubber concrete _{C 3 S / C 2 S /} CSH crystallization peak.

This may be due to an increase in the formation of the R-SO _x -R functional group on the surface of the rubber particles under catalytic oxidation. The increased XRD crystallinity of the C ₃ S/C ₂ S/CSH signal shows a stronger mechanical strength of the rubber concrete.

Scanning electron microscopy (SEM) was also used to observe the crystal and surface morphology of the hydration product of concrete containing catalytic or non-catalytic oxidized rubber particles.

The surface morphology of the rubber-concrete samples made of catalytically oxidized rubber and cement showed a fine needle-like crystalline surface without significant interface between the oxidized rubber and the cement.

This surface morphology is similar to the SEM image of a hydrated cement, which includes the needle-like crystalline surface of ettringite exhibited by general concrete and high-performance plasticizers.

The catalytic oxidized rubber containing residual condensed gas has a hydrophilic surface of the R-SO _x -R functional group and a hydrophilic sulphur trioxide (SO ₃ ) component in the high-efficiency plasticizer, which has a needle-like shape. Crystallize the surface to increase the adhesion of the rubber particles to the cement.

Therefore, the catalytic oxidized rubber particles containing the retained condensed gas have a high-efficiency plasticizer to improve the mechanical strength and shorten the hydration time of the rubber concrete.

Another surprising aspect of the present invention is that the hydrated cement containing catalytic oxidized rubber particles and cement is hydrophobic and therefore readily waterproof from the surface.

Partial oxidation of industrial-scale rubber particles is preferably carried out in a continuous reactor system, as shown in Figure 1, which controls the operating parameters to maximize the R-SO _x -R functional group on the surface of the product. At the same time avoid excessive oxidation, otherwise it will produce excessive condensation gas and toxic sulfur oxide gas.

The air in line 23 and the nitrogen in line 25 are mixed into line 26 to maintain the oxygen concentration in the gas mixture, and valves 22 and 24 are adjusted to maintain a range of 0.1 x 10 ^-3 to 100 x 10 ^-3 (mole), most Good for 1.0 x 10 ^-3 to 50 x 10 ^-3 (mole), more preferably 5.0 x 10 ^-3 to 10 x 10 ^-3 (mole).

The gas mixture flows through the valve 27 and is heated in the preheater 21 to a predetermined temperature range of 25 to 300 ° C, preferably 50 to 250 ° C, more preferably 100 to 200 ° C.

The preheated gas mixture is supplied via line 28 to horizontal tubular reactor 20, fed together with rubber particles and catalyst mixture from line 29, preferably in parallel with line 28.

When the particles are pushed through the reactor 20, the horizontal motor-driven auger 42 equipped with the spiral-shaped spiral blades 43 agitates and mixes the mixture of the rubber particles and the catalyst powder.

The rotational speed of the shaft 44 is adjusted to achieve the desired reaction time, typically from 5 to 60 minutes, preferably from 10 to 45 minutes, more preferably from 15 to 30 minutes.

Part of the oxidized rubber particles, whose viscous appearance is caused by the retained condensation gas, exits via line 30. The gas stream is removed via reactor 20, partially condensed in cooler 31, and the condensed gas (rubber oil) is removed via line 32.

The main source of rubber particles is waste tires. The steel ring, fiberglass or non-rubber material is separated from the waste tire, cryogenically frozen via liquid nitrogen or other suitable means, and then mechanically milled and screened into irregularly shaped particles of the desired size.

It includes natural rubber, styrene-butadiene rubber, butadiene rubber, butyl rubber, isoprene rubber, and a large amount of organic sulfur compounds for crosslinking and strengthening the strength of the cured rubber. The additives include zinc oxide. , carbon black, calcium carbonate and antioxidants.

In operation, the rubber particles are premixed with the metal oxide catalyst powder, and the particle size is generally in the range of 100 to 1,000 μm (micrometer), preferably 300 to 600 μm.

The weight ratio of the rubber particles to the catalyst powder is usually from 1,000 to 0.1, preferably from 500 to 0.5, more preferably from 100 to 1. Suitable metal oxide catalysts include oxides of iron, vanadium, titanium, chromium, manganese, cobalt, nickel, zinc, copper, calcium, potassium, sodium, magnesium, and the like, and oxides of mixtures thereof. The most preferred metal oxide catalyst is ferrous oxide (FeO) ferric oxide (Fe ₂ O ₃ ).

Example

A sample of the received rubber particles was prepared and analyzed, which was partially oxidized at a different temperature and reaction time with a catalyst of ferrous oxide (FeO) or ferric oxide (Fe ₂ O ₃ ).

Figure 2 illustrates the batch reactor system used to partially oxidize rubber particles under catalytic or non-catalytic conditions. The cylindrical batch reactor vessel 1 is equipped with a screen 2 to support a fixed bed 5 of rubber and catalyst mixture in the reaction zone. (No catalyst under non-catalytic conditions).

The exhaust pipe 7 is sealed from the vessel 14 of the deionized water below the valve 12, which retains the gas mixture in the reactor 1. The intake pipe 6 is connected to the air source 10 and the nitrogen source 11. Nitrogen dilutes the oxygen concentration in the air to moderate the oxidation rate.

Valves 8, 9, and 13 adjust the air/nitrogen mixture and the flow of nitrogen and air, respectively, during which a mixture of nitrogen and air is sent to the reaction zone and a rate sufficient to meet the desired oxygen concentration for a controlled rate is established. Passing through the porous rubber particles/catalyst bed; thereafter, valve 8 is closed, but valve 12 remains open, and the initial oxygen concentration in the reactor is maintained between 0.1 x 10 ^-3 and 100 x 10 ^-3 moles.

The reactor vessel 1 is heated with an electric heating ring 3 wrapped around the periphery of the vessel; a thermocouple (not shown) measures the temperature in the reaction zone, and is thereby communicatively coupled to a temperature controller 4 containing an electronic relay to regulate heating The temperature of the ring 3.

The reactor vessel is heated to the desired partial oxidation temperature, typically in the range of 25 to 300 degrees Celsius, and the partial oxidation reaction is carried out for a predetermined period of time, typically 5 after the reactor is allowed to cool to room temperature. ~60 minutes.

Metal oxide catalysts such as ferrous oxide (FeO) or ferric oxide (Fe ₂ O ₃ ) are very effective in promoting the oxidation of the -S-functional group on the surface of the rubber particles, and in the absence of a catalyst. In contrast, partial oxidation is carried out at significantly lower temperatures and shorter reaction times as well as at much lower initial oxygen levels in the reactor.

This prevents excessive oxidation of sulfur on the surface of the rubber particles, which will cause the sulfur molecules to be removed from the surface of the particles or particles (rubber desulfurization), producing toxic sulfur dioxide and sulfur trioxide gas as well as excess condensation gas as an adhesive, while in rubber particles. There are not enough ruthenium and anthraquinone functional groups on the surface.

The optimum temperature and reaction time for partial oxidation depends on the other materials, the catalytic activity of the metal oxide used, and the weight ratio of rubber particles to catalyst powder.

example 1

100 g of waste rubber tire particle size range from 300-600 μm (micron) to 1 g of ferrous oxide (FeO) catalyst powder, and then embedded in a cylindrical batch reactor, as shown in Figure 2, which has A reaction zone with a diameter of approximately 8.2 cm and a height of 19.5 cm.

A mixture of nitrogen and air having an oxygen concentration of 7.5 X 10 ^-3 (mole) is fed to the reaction zone and at a controlled rate for a period of time sufficient to establish the desired oxygen concentration through the porous bed of rubber particles; thereafter, the inlet Valve 8 is closed and outlet valve (valve 12) remains open.

The test was then carried out in divided portions and the vessel was heated with an electric heating ring to partial oxidation temperatures of 150, 200, 250 and 300 degrees. The partial oxidation temperature is maintained and regulated by the relay controller as shown in Figure 2. Fractional tests were carried out at each temperature and were carried out at partial oxidation times of 20, 30 and 60 minutes, respectively, before allowing the reactor to cool to room temperature (RT).

Partially oxidized rubber particles have a viscous oily appearance and are first removed from the reactor. A portion of the condensed gas (small amount) was collected, and the reactor was purged with acetone as "rubber oil", and a large amount of condensed gas was introduced into the bottom of the reactor water vessel 14 through the bed of porous rubber particles, which emulsified the water into "sulfurized water".

In all the fractional tests, the comparison was repeated with (i) ferric oxide (Fe ₂ O ₃ ) catalyst and (ii) no catalyst, respectively. The molecular weight of the ferrous oxide (FeO) catalyst was 71.85. This data was obtained from Nippon Pure Chemical Industries, Ltd. (batch No. J030619025), and the iron oxide (Fe ₂ O ₃ ) catalyst had a molecular weight of 159.69 and a purity of 96%. , acid insoluble 1.5% (maximum), water 1.5% (maximum) and manganese (same as manganese dioxide) 0.5%, this information is also obtained from Lin Chun Pharmaceutical Co., Ltd. (batch number. JJB00743).

Example 2

In Example 1, rubber samples produced by ferrous oxide (FeO), ferric oxide (Fe ₂ O ₃ ) and partial oxidation without catalyst, and non-oxidized rubber samples received, the surface functional groups were subjected to FT-IR spectroscopy. To analyze. From its FT-IR spectrum, the best partial oxidation is derived from ferrous oxide (FeO) or ferric oxide (Fe ₂ O ₃ ) catalysts at lower temperatures from 150-200 ° C and shorter reaction times. It is carried out under 20-30 minutes.

Figure 3 is the following FT-IR spectrum: (1) untreated rubber particles and (2) treated rubber particles, with no catalyst, ferrous oxide (FeO) at 150 ° C for 20 minutes The catalyst or the ferric oxide (Fe ₂ O ₃ ) catalyst is subjected to an oxidation treatment. Its initial oxygen concentration is 7.5 x 10 ^-3 moles.

All four curves show absorption near 7 zones: 3,800-3,600 cm ^-1 with OH (hydrogen-oxygen) bond stretching, 2,700-2,900 cm ^-1 and 850-950 cm ^-1 with CH (hydrogen-oxygen) Stretching of the bond, stretching of 1,780-1,660 cm ^-1 with C=O (carbon = oxygen) bond, bending of 1500 cm ^-1 with CH (hydrogen-oxygen) bond, 1,100-1,000 cm ^-1 with S=O Stretching of (sulfur = oxygen) bond, stretching of 700-600 cm ^-1 with CS (carbon-sulfur) bond, and stretching of 550-450 cm ^-1 with SS (sulfur-sulfur) bond.

Figure 4 is the following FT-IR spectrum: (1) untreated rubber particles and (2) treated rubber particles, without catalyst, ferrous oxide (FeO) at 200 ° C for 30 minutes The catalyst or the ferric oxide (Fe ₂ O ₃ ) catalyst is subjected to an oxidation treatment. Its initial oxygen concentration is 7.5 x 10 ^-3 moles.

Figure 3 and Figure 4 show that all of the surface functional groups of rubber particles oxidized with ferrous oxide (FeO) or ferric oxide (Fe ₂ O ₃ ) catalysts have a lower absorption force than catalyst-free oxidation or Untreated samples are also strong, especially those in the vicinity of S=O stretching, CS stretching, SS stretching, CH (carbon-hydrogen) bending, and CH (hydrocarbon) stretching.

The most likely cause is that ferrous oxide (FeO) or ferric oxide (Fe ₂ O ₃ ) catalyst promotes surface sulfur molecules to become sub-arsenic (R-SO-R) and/or rhodium (R) at a higher conversion rate. -SO _x -R) caused by part of the body.

Example 3

In order to search for partial oxidation conditions for optimal treatment of rubber particles, the area of the tensile absorption force of the sp ³ CH bond and the area of the tensile absorption force of the SO _x (sulfur oxide) (including sulfur dioxide and sulfur oxide, etc.) bonds are integrated. Under the FeO(Fe ²⁺ ) or Fe ₂ O ₃ (Fe ³⁺ ) catalyst type partial rubber particle sample, FIG. 5 shows the relationship between the area ratio of SO _x /sp ³ CH and the partial oxidation temperature. The area ratio of a partial oxidation index for forming the surface of SO _x (sulfur oxides) yl group desired. Among them, the oxidation reaction time of 20, 30 and 60 minutes was taken as a parameter. Obviously, the maximum area ratio of the Fe ²⁺ catalyst/20 minute sample is about 1.48 at 150 degrees Celsius, which is the highest; the area ratio also drops sharply as the temperature rises from 200 degrees Celsius to 300 degrees Celsius; Fe The area ratio curve of the ³⁺ catalyst/30 minute sample also rose to another high point (about 1.52) at 200 degrees Celsius.

At 60 minutes, a longer processing time, regardless of the processing temperature or catalyst used, the area ratio is a significantly lower standard between 1.1 and 1.2. Figure 5 shows that Fe ²⁺ and Fe ³⁺ catalysts promote the oxidation of sulfur on the surface to more desirable SO _x (sulfur oxide) of rubber particles in a large reduction in reaction time and temperature compared to partial oxidation without catalyst. The surface of the group.

In addition to the advantageous catalytic effect, the presence of Fe ²⁺ or Fe ³⁺ also significantly causes the sulfur molecules on the surface of the rubber particles to compete with the iron (Fe) molecules on the catalyst for the available oxygen molecules in the gas phase. As shown in Figure 5, the competition reactions were highest at 20 or 30 minutes of reaction time and a longer reaction time (60 minutes).

In other words, the effect of the competitive reaction significantly reduces the temperature of the oxidized surface sulfur compound (RS) to convert it to surface enthalpy (RSO ₂ ) or yttrium (RSO), thereby reducing the likelihood of cracking and becoming lighter. The sputum or alum, so that it becomes part of the condensate at higher temperatures.

According to the exothermic reaction of oxidation reduction, it is known that iron oxide (FeO) is easily decomposed according to the following formula under heating (less than 576 degrees Celsius), : 4 FeO→Fe+Fe ₃ O ₄ (1)

The reaction exotherms and promotes partial oxidation of the sulfur compound on the rubber surface at the temperature and time of the reduction reaction.

The best temperature and time for treating rubber particles using iron oxide (FeO) catalyst are 150 ° C and 20 minutes, respectively. On the other hand, at high temperatures, ferrous oxide (Fe ₂ O ₃ ) and the surface of rubber particles The endothermic reaction of the carbon molecule in the reduction: 2 Fe ₂ O ₃ + 3C → 4Fe + 3CO ₂ (2)

The reaction absorbs heat from the reactor, resulting in partial oxidation of the sulfur compound on the surface of the rubber particles at a higher temperature and longer processing time than iron oxide (FeO).

The best temperature and time for treating the rubber particles using a ferric oxide (Fe ₂ O ₃ ) catalyst were 200 ° C and 30 minutes, respectively. Obviously, it is subjected to milder conditions than the catalyst-free treatment, and the catalyst-free treatment requires a higher temperature (250 ° C) and a longer reaction time (one hour).

Example 4

The rubber oil samples obtained from the experiment were collected at a reaction temperature of 150, 200, 250 and 300 ° C and a reaction time of 20, 30 and 60 minutes, using ferrous oxide (FeO) or ferric oxide (Fe ₂ O ₃ ). As a catalyst, the condensation gas was purged in a reactor vessel with acetone and concentrated by evaporating acetone from the sample. The concentrated rubber oil sample was then analyzed by FT-IR.

Figure 6 shows the FT-IR spectrum of the rubber oil produced by partial oxidation of rubber particles. At a reaction temperature of 150 ° C and a reaction time of 20 minutes, ferrous oxide (FeO) or ferric oxide (Fe ₂ O ₃ ) is used. As a catalyst. It is not surprising that the rubber oil is stretched and bent with the CH bond and the absorption with the S=O bond is significantly stronger than the surface of the partially oxidized rubber particles (see Figure 3). This is because the rubber oil is mainly composed of short-chain R-SO _x -R components (R-SO-R, R-SO ₂ -R, and R-SO ₃ ).

Figure 6 also indicates that the absorption peak of the rubber oil produced by the ferric oxide (Fe ₂ O ₃ ) catalyst is significantly larger than that produced by the ferrous oxide (FeO) catalyst, which means that ferric oxide (Fe ₂ O) ₃ ) The catalyst causes a relatively high amount of rubber particles to be excessively oxidized, where more sulfur molecules are driven from the surface of the rubber particles to form a gaseous R-SO _x -R which is condensed into a portion of the rubber oil.

The higher over-oxidation caused by the use of ferric oxide (Fe ₂ O ₃ ) catalysts is most likely due to the additional heat generated in the reactor, which is locally derived from ferric oxide (Fe ₂ O). ₃ ) required for the endothermic reduction reaction, as described above.

The rubber oil produced from the rubber of waste tires is catalyzed by partial oxidation of metal oxides and can be used as an adhesive. Its characteristics are comparable or superior to conventional high-efficiency plasticizers to enhance partially oxidized rubber particles and Bonding strength of the surrounding cement matrix.

In all experiments, homogeneous emulsion sulphide water was produced by intercepting a large amount of condensed gas into the sealed water at the outlet of the bottom of the reactor. The majority of the major functional groups in the condensing gas are hydrophilic and water-soluble cerium, cerium and organic sulfur trioxide.

In addition to rubber oil, the sulfide water can be used as water for hydration of rubber concrete to further improve its mechanical strength as an adhesive for rubber and surrounding cement particles.

Example 5

A rubber cement made of partially oxidized rubber particles produced by using ferrous oxide as a catalyst at 150 ° C for 20 minutes and with ferric oxide as a catalyst at 200 ° C for 30 minutes. In the case of rubber cement made of catalyst-free rubber particles, the following hydrated mortar must be prepared:

1. RT cement/sand composite is a cement/sand composite that produces cement/sand and 6 wt% of accepted (untreated) rubber particles.

2. The rubber cement/sand composite of 150 °C is a cement/sand composite material, which is prepared with cement/sand and 6 wt% of partially oxidized rubber particles, and has no catalyst at 150 ° C for 20 minutes.

3. Fe ²⁺ +150 °C rubber cement / sand composite material is a cement / sand composite material, prepared cement / sand and 6wt% of partially oxidized rubber particles, at 150 ° C, 20 minutes environment, there is ferrous oxide catalyst .

4. 200 °C rubber cement / sand composite material is a cement / sand composite material, prepared cement / sand and 6wt% of partially oxidized rubber particles, at 200 ° C, 30 minutes of environment, no catalyst.

5. Fe ³⁺ +200°C rubber cement/sand composite is a cement/sand composite material, which prepares cement/sand and 6wt% of partially oxidized rubber particles. At 200°C for 30 minutes, there is a ferric oxide catalyst. .

6. Pure cement/sand composite is a cement/sand composite that requires only cement/sand to be prepared.

Water was added to the mixture at a weight ratio of 0.62:1 to prepare a cement/sand composite sample for hydration which allowed cure for 7 days prior to testing.

Example 6

The hydrated cement sample prepared in Example 5 was analyzed by FT-IR spectroscopy, and the excellent properties of the rubber concrete obtained by catalytically oxidizing the rubber particles were confirmed. As shown in Figure 7, the FT- of the Fe ²⁺ +150 °C rubber cement/sand composite is compared to the pure cement/sand composite (normal cement/sand composite) near 878, 670 and 1000 cm ^-1 wavenumber. The IR spectrum significantly exhibits a stronger CSH signal.

As mentioned above, C ₃ S and C ₂ S are the main components of cement, which produce CSH in hydration, as a main compound, giving the cement/sand composite its own mechanical strength. The FT-IR spectrum of the RT cement/sand composite and the rubber cement/sand composite at 150 °C showed no significant CSH signal, indicating that the surface of the untreated rubber particles had no R-SO _x -R functional groups and was expressed at 150 ° C. In the absence of a catalyst for 20 minutes, there are only a few R-SO _x -R functional group structures on the surface of the rubber particles.

Compared to pure cement/sand composites (common cement/sand composites), the FT-IR spectra of the Fe ³⁺ +200 °C rubber cement/sand composites shown in Figure 8 are near 878, 670 and 1000 cm ^-1 wavenumbers. It also significantly shows a stronger CSH signal. The FT-IR spectrum of the RT cement/sand composite and the 200 °C catalyst-free rubber cement/sand composite show no significant CSH signal and therefore exhibit relatively weak mechanical strength.

Example 7

To further demonstrate the benefits of using catalytic oxidized rubber particles relative to non-catalytic oxidized rubber particles in rubber concrete fabrication, some of the hydrated cement samples in Example 5 were analyzed by X-ray diffraction (XRD) spectroscopy. The XRD spectrum of the pure cement/sand composite (normal cement/sand composite) shown in Fig. 9 shows the C ₃ S/C ₂ S/CSH crystallization peak as a base case.

In the XRD spectrum, the crystallization peaks are significantly lower than the rubber cement/sand composites of 150 ° C and 200 ° C, respectively, in the X-ray diffraction spectrum, as shown in Figures 10 and 11, the mechanical strength of the rubber concrete is higher than that of ordinary concrete. Weak.

However, as shown in Figures 12 and 13, the X 3RD of the C ₃ S/C ₂ S/CSH crystallization peak in the Fe ²⁺ +150 °C rubber cement/sand composite and the Fe ³⁺ +200 °C rubber cement/sand composite In the spectrum, it is similar or even greater than the XRD spectrum of a pure cement/sand composite (common cement/sand composite). This example further demonstrates that partial oxidation of rubber particles by metal oxide at lower temperatures and shorter processing times does increase the strength of rubber concrete containing the oxidized rubber particles.

Example 8

Scanning electron microscopy (SEM) was used to compare the crystal and surface morphology of the hydration product of a sample of rubber concrete, including catalytically oxidized and non-catalyzed oxidized rubber particles.

As shown in Fig. 14, the surface morphology of the rubber concrete sample made of Fe ²⁺ + 150 °C rubber cement/sand composite showed a needle-like crystal surface, but there was no obvious interface between the catalytic oxidized rubber and the cement.

This surface is similar to scanning electron microscopy (SEM) images of hydrated cement, including common cement/sand composites showing the acicular crystal surface of ettringite and high-efficiency plasticization. The results of this example show that the catalytically oxidized rubber particles are an excellent high-efficiency plasticizer for improving mechanical strength and shortening the hydration time of rubber concrete.

Example 9

Compared with ordinary cement/sand composites, rubber cement/sand composites improve hydrophobic surface properties due to poor compatibility between hydrophobic rubber particles and hydrophilic cement, when rubber hydrated cement is cement and (i) The untreated rubber particles or (ii) the partially oxidized rubber particles from the catalyst-free, the space for improvement is rather limited.

Surprisingly, rubber hydrated cement made from cement and catalytically oxidized rubber particles has greatly improved drainage. Figure 15 is a 28-day hydration clay image of pure cement/sand composite, 150 °C rubber cement/sand composite, 200 °C rubber cement/sand composite, Fe ²⁺ +150 °C rubber cement/sand composite and Fe ³⁺ +200 °C rubber cement / sand composite.

The waterproof performance of Fe ²⁺ +150°C rubber cement/sand composite and Fe ³⁺ +200°C rubber cement/sand composite is better than that of pure cement/sand composite and other cement/sand composites containing non-catalytic oxidized rubber. material.

The foregoing has described the principles, preferred embodiments, and modes of operation of the invention. However, the invention should not be construed as being limited to the specific embodiments discussed. Rather, the above-described embodiments are to be considered as illustrative and not restrictive, and the scope of the invention as defined by the following claims Changes are made to these embodiments.

1‧‧‧reactor vessel

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Claims (20)

A method of producing a partially oxidized rubber by oxidizing rubber particles, comprising: contacting the rubber particles with an oxidant gas in the presence of a catalyst under conditions sufficient to selectively oxidize rubber particles, the rubber particles comprising an organic sulfur compound a polymer such that the organosulfur compound on the surface of the rubber particle is converted into a functional group selected from the group consisting of an anthracene (R-SO-R), 碸 (R) -SO ₂ -R), the group of sulfur trioxide (R-SO ₃ ) and mixtures thereof, wherein R represents a hydrocarbon in the rubber particulate polymer, and wherein the catalyst contains a metal oxide. The method of producing an oxidized rubber particle according to claim 1, wherein the rubber particle is exposed to the oxidant gas in an environment of 25 to 300 ° C for 5 to 60 minutes. The method of producing oxidized rubber particles according to claim 1, wherein the rubber particles are exposed to the oxidant gas in an environment of 50 to 250 ° C for 10 to 45 minutes. The method of producing an oxidized rubber particle according to the first aspect of the invention, wherein the selective oxidation reaction of the rubber particle produces a condensation gas which is suitable as an adhesive. The method of producing oxidized rubber particles according to claim 1, wherein the metal oxide is selected from the group consisting of iron, vanadium, titanium, chromium, manganese, cobalt, nickel, zinc. , copper, calcium, potassium, sodium, magnesium and mixtures thereof. A method of producing a partially oxidized rubber according to the oxidized rubber particles of claim 1, wherein the metal oxide comprises ferrous oxide (FeO), ferric oxide (Fe ₂ O ₃ ), and a mixture thereof. A method of producing a partially oxidized rubber according to the oxidized rubber particles of claim 1, wherein the rubber particles are recovered from waste tires. A continuous catalytic reactor system for selectively oxidizing rubber particles, comprising: a catalytic reactor having a rubber particle inlet and a rubber particle outlet, The rubber particles are contacted with a metal oxide catalyst in an oxidant environment; a means for continuously introducing rubber particles through the rubber particle inlet into the catalytic reactor; and a means for recovering partially oxidized rubber particles And condensation gas. The continuous catalytic reactor system of claim 8, wherein the means for continuously introducing the rubber particles comprises mixing the metal particles as the rubber particles advance through the reactor toward the rubber particle outlet Catalyst and the rubber particles. The continuous catalytic reactor system of claim 8, further comprising a means for introducing preheated oxygen into the catalytic reactor. The continuous catalytic reactor system of claim 10, wherein the catalytic reactor has an elongated reaction zone, and oxygen flows in the same direction as the rubber particles flow through the reaction zone. The continuous catalytic reactor system of claim 8, wherein the rubber particles are obtained from recycled waste tires, mechanically ground and screened into irregular particles of a desired size, and the volume ranges from 100 to 1000 μ. m (micron). A concrete composite comprising a cement and a surface treated rubber particle comprising a polymer crosslinked with an organosulfur compound, the surface treated rubber particle is partially oxidized, and has sulfur content a hydrophilic reactive functional group reactive with a matrix of the cement and a hydrophilic group of a liquid adhesive, wherein the liquid adhesive comprises at least 0.1% by weight of the concrete composite through which the surface The processed rubber particles and the preparation process of the adhesive include: oxidizing the rubber particles to produce a partially oxidized rubber, comprising: reacting the rubber particles with a catalyst under conditions sufficient to selectively oxidize the rubber particles In the case of contact with an oxidant gas, the rubber particles comprise a polymer crosslinked with an organosulfur compound such that the organosulfur compound is converted on the surface of the rubber particle into a functional group selected from the group consisting of sulfoxide (R-SO-R), sulfone (R-SO ₂ -R), wherein one of sulfur trioxide (R-SO _3), and mixtures, wherein R represents the micro rubber Hydrocarbon polymers, and wherein the catalyst comprising a metal oxide. The concrete composite material according to claim 13 of the patent application, which has a compressive strength after curing, which exceeds the conventional non-rubber concrete. The concrete composite material according to claim 13 of the patent application, which has a flexural strength after curing, which exceeds the conventional non-rubber concrete. The concrete composite material according to claim 13 of the patent application, which has a tensile strength after curing, which exceeds the conventional non-rubber concrete. The concrete composite material as described in claim 13 does not include a high-efficiency plasticizer. The concrete composite according to claim 13, wherein the catalyst is the metal oxide selected from the group consisting of iron, vanadium, titanium, chromium, manganese, cobalt, nickel, zinc, copper, calcium, potassium, sodium. a metal oxide of one of magnesium, magnesium and mixtures thereof. The concrete composite according to claim 13, wherein the metal oxide comprises ferrous oxide (FeO), ferric oxide (Fe ₂ O ₃ ), and a mixture thereof. The concrete composite of claim 13, wherein the rubber particles are recovered from waste tires.