HK1165452B - Method for rejuvenating a bitumen containing composition - Google Patents

Description

Process for rejuvenating bitumen-containing compositions

The invention relates to a regeneration method of a composition containing asphalt (bitumen).

In the prior art, several methods for rejuvenating bitumen containing compositions are known. An example of this is disclosed in R.Romera, Project 1992-. The following regeneration additives have been tested herein: commercially available aromatic oil, recovered aromatic motor oil (recycled oil), and soft 150/200 penetration asphalt. Studies have shown that the best composition contains 80% aged bitumen and 20% motor oil. Cashew nut shell oil is not mentioned.

WO/2008/084014, Shell International research Maatschappij BV, filed as Hainan (NL), also discloses a rejuvenating agent and a method for rejuvenating asphalt (asphal). A composition comprising bitumen and palm oil is used as rejuvenating agent.

Examples of other rejuvenating agents known in the art are paraffin wax and rapeseed oil, etc. However, these rejuvenating agents, like palm oil, have the serious disadvantage that they make the bitumen too soft and therefore the viscosity of the bitumen-containing composition (e.g. asphalt) also becomes too low. In the case of asphalt, for example, in this case, the adhesion of asphalt to aggregate is reduced due to these recycling agents, and thus the durability of asphalt is impaired. And these rejuvenating agents also have poor miscibility with asphalt.

Furthermore, petrochemical resins can also be present as rejuvenating agents for bitumen containing compositions, but they are very expensive.

It is known in the art to recover asphalt and other bituminous compositions. For this purpose, these compositions are usually ground and added to the new composition to be prepared or are themselves regenerated by adding suitable additives. In this case, it is also necessary to add fresh bitumen to the composition at all times in order to guarantee the workability and the quality (durability, life) of the composition. In other words, it has not been possible until now for compositions comprising only recycled bituminous material to have good properties when in actual use. Despite the presence of the compositions, these compositions can only be applied where their inferior properties are not much affected. For example, the machined asphalt is reused for roadside reinforcing edges without the addition of fresh asphalt. However, this material is completely unsuitable for use as a new road surface.

The amount of suitable bitumen available has been significantly reduced in recent years. This is due to the fact that the temperature of the distilled oil is higher and lower, and thus the remaining heavy fraction is less and less. Furthermore, the heavy fraction is upgraded to obtain more useful and thus more valuable products. Therefore, the amount of asphalt available is reduced and the quality of asphalt is increasingly poor. Today, for the reasons mentioned above, new bitumens are prepared even from other chemicals.

Bitumen-containing compositions are very sensitive to ageing and therefore need to be replaced in time when the properties decline over time. Aging of bituminous compositions can result from different mechanisms including oxidation, volatilization of substances, uv attack, bleeding and orientation. In this process, partially maltene (maltene) is converted to asphaltene, and the material becomes more brittle. Aging qualitatively reduces the properties required for processing and application. The compositions often become harder, more brittle, less tough, and less recyclable over time.

Most bitumens are used in road asphalt. Asphalt ages faster due to erosion and weather effects and is usually replaced within a decade. For this purpose, the asphalt is removed from the road surface and reduced in volume by grinding. The ground product was recovered with a small amount of fresh asphalt product. Today, the actual recycling of such ground asphalt, while maintaining good asphalt properties, is only possible at great expense, for example by adding some special chemicals or fresh bitumen.

There is therefore a need in the art for a bitumen rejuvenation process that allows old bitumen containing compositions to be recycled. Until now, this method seems to be impossible or only very expensive to implement.

The present invention is intended to meet the said need, providing a process for rejuvenating a bitumen-containing composition, said process comprising: to the bitumen containing composition is added a distillation residue of Cashew Nut Shell Liquid (CNSL), obtained by distillation of cashew nut shell liquid at a temperature of up to 250 ℃ to 350 ℃, preferably at a temperature of up to 300 ℃ to 340 ℃, most preferably at a temperature of up to 310 ℃ to 320 ℃.

Surprisingly, it has been found that by adding a relatively small amount of this particular CNSL distillate residue, the bitumen in the composition is rejuvenated so that its properties are improved and the bitumen becomes suitable for its regular use. In some cases, the reclaimed asphalt may even perform better than the fresh asphalt in some properties.

The CNSL raffinate that must be added is not irritating and therefore can be processed properly without adverse consequences for the user. This is particularly advantageous in, for example, road construction, since the asphalt is applied at high temperatures. In addition, CNSL is a natural product with great technical advantages.

CNSL is a resin extracted from the shell of cashew nuts and is available in large quantities. The resin consists essentially entirely of phenolic compounds having a chain length of substantially 15 carbon atoms and varying degrees of unsaturation and being meta-substituted on the phenolic ring.

EP-A-1642935 itself discloses ｃA bituminous binder for use, for example, in road construction, for the surface treatment of an asphalt mixture system. The binder comprises the main components bitumen and a fluxing agent (fluxing agent), for example a reactive fluxing agent such as Cashew Nut Shell Liquid (CNSL), cardol or cardanol. CNSL here means the distillation product of cashew nut shell liquid and not the distillation residue. The distillation product is a reactive product intended to change properties in a reactive manner. The distillation residue in the present invention is non-reactive and is used to physically modify the properties of the bitumen containing composition.

CNSL in the prior art essentially refers to its "reactive" distillation product, not to the "non-reactive" cashew nut shell liquid obtained by extraction from cashew nut shells, nor to the "non-reactive" distillation residue of the present invention.

The CNSL raffinate used in the present invention is mainly composed of a mixture of a polymerization product of 3-pentadecaalkenylphenol and 3-pentadecadienylresorcinol, which is present in the form of an alkylphenol resin that is liquid at room temperature. The chain length is about 13-16 carbon atoms.

Rejuvenation of bitumen means that the properties of the used bitumen are improved so that the bitumen regains properties superior to those of the used bitumen, advantageously comparable to those of fresh bitumen, and in particular better than those of fresh bitumen.

Advantageously, the viscosity of the distillation residue is from 1,000 to 30,000mPa.s^-1Preferably 1,000 to 10,000mpa.s^-1More preferably 1,000 to 2,500mpa.s^-1Most preferably the viscosity is substantially 1,500mpa.s^-1. A distillation residue having such a viscosity is particularly suitable for bitumen regeneration.

In a particular embodiment of the invention, the distillation residue has an average saturation factor of from 1 to 5, preferably from 1.2 to 1.3.

Advantageously, the bituminous composition is selected from: bitumen, asphalt, insulation, coastal covering material and anti-drum plate (anti-drum plate).

All of these bituminous compositions may be rejuvenated by adding the specific CNSL distillate of the present invention such that these bituminous compositions are suitable for recovery without the addition of fresh bitumen, but of course the addition of fresh bitumen is not excluded.

To further improve the properties of the reclaimed bituminous composition, the bituminous composition may even additionally comprise one or more of the following: vegetable or non-vegetable resins, vegetable or non-vegetable oils, paraffins, polymers such as EVA, SBS, APP, PE, metallocenes and synthetic waxes.

The present invention also provides a bitumen containing composition which has been rejuvenated by using the method of the invention.

Preferably, the reclaimed asphalt-containing composition is selected from the group consisting of: asphalt, insulation, roofing, coastal covering, and anti-drum plates.

The invention will be further illustrated below by means of some examples of methods for rejuvenating bitumen-containing compositions.

Example 1:

method for regenerating recycled roof tiles containing asphalt

The roof tiles used were roof siding laid in the netherlands at the roofs of various locations for about 20 years. Roofing bitumen comes from a variety of sources: in addition to the renovation of scrap, there are also demolition waste. This aged asphalt roofing material comprises 50 wt% of an asphalt containing atactic polypropylene (APP) (polymer modified asphalt), the remainder being filler and rupture material. The size of the plate tile is reduced by mechanical means.

Furthermore, a series of mixtures (see table 1) were prepared by adding different amounts of CNSL distillation bottoms to the slate, obtained from distillation of cashew nut shell liquid at temperatures up to 315 ℃. The series of samples was accelerated aged at 80 ℃ for one week and 70 ℃ for 12 weeks. Both ages were performed according to the standard artificial aging methods described in NEN-EN 495-5 and NEN-EN 129.

TABLE 1

These tests show that the aging process using CNSL is slower than that of the slate made with fresh asphalt (2008. product).

After the test is completed, test pieces with more than 10% CNSL additive, including 25%, are applied to a roof of heerhugowaard (nl). During processing, slate tiles with 10% and 15% CNSL added to the recycled aged roofing asphalt exhibited poor processability. These tiles are too rigid when processed at ambient temperatures of 12 ℃. The tile with 20% CNSL added showed the best processability. The composition is most similar to a fresh asphalt based slate (2008. product).

Example 2:

process for rejuvenating a reclaimed asphalt-containing milled asphalt composition

In the asphalt test, a rheology test was carried out by measuring the viscosity at different temperatures of a mixture of aged road asphalt and aged roofing asphalt, wherein said mixture was simultaneously mixed with different percentages of CNSL raffinate from cashew nut shell liquid distilled at temperatures up to 315 ℃. The results are shown in Table 2.

TABLE 2

In the rheology test, roofing bitumen and CNSL were used in fixed ratios. Roof asphalt in a proportion of 4 parts: 1 part of CNSL raffinate (by weight). The source of roofing bitumen was the same as in the test described above. The aged road asphalt is obtained by milling different asphalt road asphalt. The milled asphalt is heated in a heated drum and mixed with roof granules (roof granules). The roof ballast is premixed with CNSL raffinate and then added cold to the preheated mineral and milled asphalt in the asphalt mixer. The mixture was mixed homogeneously and tested separately as shown in table 3.

TABLE 3

The test area for asphalt in blend 2 was in a commercial area of Breda, 3 meters wide by 25 meters long for 6 months in 2008. The treatment is carried out in a conventional manner using a standard asphalt applicator (asphalapplication machine) and the asphalt is compacted in a conventional manner using a steel roller compactor. The asphalt mixture was processed in the same way as standard DAB 0/16. The properties of the asphalt also fall within the product parameters of DAB 0/16 (see table above).

Explanation of the raw materials:

and (3) roof granulated slag:this is a mixture of different bituminous roofing materials obtained from demolition workers and repair companies that replace old bituminous roofs. These demolition waste materials are less odorous and homogenized. It consists essentially of an APP modified asphalt with mineral and glass fiber reinforcement. When milling, a granulate residue is obtained which can vary in size from 0.5 mm to 15 mm.

Milling asphalt:this is the asphalt particles obtained by milling aged or damaged asphalt. Selectively milled to keep particles of different qualities separate, such as DAB, STAB, ZOAB, etc. The milled particles were classified by sieving.

CNSL raffinate:this is cashew nutThe shell liquid feed distills the resulting residual product up to 315 ℃.

All major components of DAB 0/16 were products from the residual stream and by mixing in the proportions described, an asphalt composition equivalent to asphalt based on virgin feedstock was obtained.

Claims (19)

1. A process for rejuvenating a bitumen containing composition, said process comprising adding to the bitumen containing composition a distillation residue of cashew nut shell liquid obtained by distillation of cashew nut shell liquid at a temperature of up to between 250 and 350 ℃.

2. The process according to claim 1, characterized in that the viscosity of the distillation residue is from 1,000 to 30,000mPa.s^-1In the meantime.

3. The process according to claim 1, characterized in that the viscosity of the distillation residue is from 1,000 to 10,000mPa.s^-1In the meantime.

4. The process according to claim 1, characterized in that the viscosity of the distillation residue is from 1,000 to 2,500mPa.s^-1In the meantime.

5. The process according to claim 1, characterized in that the viscosity of the distillation residue is 1,500mpa.s^-1。

6. A process according to claim 1 or 2, characterized in that the distillation residue has an average saturation factor of 1 to 5.

7. A process according to claim 1 or 2, characterized in that the distillation residue has an average saturation factor of 1.2 to 1.3.

8. The process according to claim 1 or 2, characterized in that the bituminous composition is selected from the group consisting of: asphalt, roof coverings, insulation, coastal coverings, and anti-drum plates.

9. A process according to claim 1 or 2, characterized in that the bitumen containing composition additionally comprises one or more of the following: vegetable or non-vegetable resins, vegetable or non-vegetable oils, paraffins, polymers, metallocenes and synthetic waxes.

10. The method of claim 9 wherein the polymer is ethylene-vinyl acetate polymer, styrene-butadiene-styrene copolymer, atactic polypropylene, and polyethylene.

11. A bitumen containing composition which has been rejuvenated by using the method of any one of claims 1 to 10.

12. A bitumen containing composition according to claim 11, characterised in that the rejuvenated bitumen containing composition is selected from the group consisting of: asphalt, insulation, roof covering, shore covering, and anti-drum panels.

13. A process for rejuvenating bitumen, said process comprising adding to the bitumen a distillation residue of cashew nut shell liquid obtained by distillation of cashew nut shell liquid at a temperature of up to between 250 and 350 ℃.

14. The process according to claim 13, characterized in that the viscosity of the distillation residue is from 1,000 to 30,000mpa.s^-1In the meantime.

15. The process according to claim 13, characterized in that the viscosity of the distillation residue is from 1,000 to 10,000mpa.s^-1In the meantime.

16. The process according to claim 13, characterized in that the viscosity of the distillation residue is from 1,000 to 2,500mpa.s^-1In the meantime.

17. The process according to claim 13, characterized in that the viscosity of the distillation residue is 1,500mpa.s^-1。

18. The process according to claim 13 or 14, characterized in that the distillation residue has an average saturation factor of 1 to 5.

19. The process according to claim 13 or 14, characterized in that the distillation residue has an average saturation factor of 1.2 to 1.3.