FR2613375A1 - PROCESS FOR THE PREPARATION OF A BITUMEN AND POLYMER-BASED BINDER - Google Patents

Abstract

PROCESS FOR THE PREPARATION OF A BINDER BASED ON BITUMEN AND POLYMERS, CHARACTERIZED BY THE FACT THAT WE ADD TO A BITUMEN, A PREPARED MIXTURE, COMPRISING A COPOLYMER VINYL ETHYLENEACETATE AND A POLYISOBUTYLENE WEIGHT BETWEEN AYULANTAR 400 AND 1000.

Description

Process for the preparation of a binder based on bitumen and polymers.

  The subject of the invention is a process for preparing compositions based on bitumen and polymers intended in particular to be used as

  road or waterproofing coatings.

  It is known that polybutenes such as polybutylene and polyisobutylene are compatible with polyethylenes, polyethylene waxes, polyisobutylenes such as those sold under the name VISTANEX, butyl rubbers, regenerated rubbers, butadiene-styrene copolymers (GRS) ), petroleum resins such as resins

dienic.

  The Applicant has discovered that by combining a polybutene with a copolymer of ethylene and vinyl acetate and by introducing this previously prepared mixture into bitumen, it was possible to surprisingly reinforce the properties of

  consistency and softening of the bituminous binder.

  The subject of the invention is therefore a process for the preparation of a bitumen-polymer mixture comprising, in a first step, the preparation of a single additive based on polybutene and of an ethylene / vinyl acetate copolymer and l addition of this additive to bitumen. This process is particularly advantageous since a simple mixing, for example in a static mixer, of the additive with the bitumen is sufficient, while the addition of the ethylene / vinyl acetate copolymer or of the polybutene separately requires a mixing for several hours using a paddle mixer which leads to a less uniformity of the properties of the bitumen / additive mixture based on

  polybutene and ethylene / vinyl acetate copolymer.

  Another object of the invention is constituted

by the additive thus prepared.

  The invention also relates to the production of coatings or seals making

works the product thus obtained.

  Other objects of the invention will become apparent

  reading the description and examples which

follow.

  The process according to the invention essentially consists in adding to a bitumen, a mixture, prepared beforehand, comprising an ethylene / vinyl acetate copolymer and a polyisobutylene having a weight

  molecular between 400 and 1000.

  Another subject of the invention is the composition comprising the mixture of the ethylene / vinyl acetate copolymer and of polyisobutylene. This is preferably prepared by progressive addition of granules of ethylene / vinyl acetate copolymer in polyisobutylene liquid at a temperature slightly higher than the dissolution temperature of the ethylene / vinyl acetate copolymer by mixing in a mixer.

  with slow paddles or pump injection and stirring.

  The ethylene / vinyl acetate copolymer is preferably a copolymer comprising 5 to 45% by weight of vinyl acetate units and preferably a proportion of less than 20% and a melt index of between 0.1 and 600 and preferably between between and 200. The polyisobutylene preferably has a molecular weight of less than 1000 and greater than 400. The mixing of polymers is carried out in polyisobutylene / ethylene-vinyl acetate ratios of between

  90/10 and 50/50 and preferably of the order of 80/20.

  The bitumen is preferably a blown or direct road bitumen, well known in the state of the art. The composition based on the mixture of polymers is added to this bitumen preferably in proportions of 1 to 35% relative to the total weight of the composition and preferably in proportions of 5 to%. The Applicant has found that it is possible to prepare a bituminous binder directly on site by mixing the composition based on polymers as defined above and on bitumen in times of less than 1/4 hour with, for example a paddle mixer or almost immediately with a

static mixer.

  The Applicant has found that the addition of the composition containing the mixture of polymers as defined above, makes it possible to obtain a synergistic effect by increasing the softening point and at the same time lowering the point of weakness. Cold. Thus, thanks to the association, it is possible to improve the plasticity interval and the penetration index. This is particularly surprising considering the properties

isolated polymers.

  Another advantage of the invention is that the composition based on the mixture of polymers intended to be added to the bitumen can be stored without problem over a long period without degradation and while retaining the starting viscosity. The road surfaces thus produced behave particularly well in high heat, the Applicant has found that the binder retains a sufficient consistency and viscosity to prevent any irreversible deformation by creep of the coating,

  especially under the action of heavy traffic.

  Furthermore, in cold weather, the binder thus applied has resistance to cold cracking which allows the coating to withstand winter stresses such as the use of studded tires. The bituminous binders thus prepared also have elasticity properties,

  tenacity, adhesiveness to remarkable aggregates.

  The following examples are intended to illustrate the invention without, however, being limiting in nature.

EXAMPLE 1

  23 parts of an ethylene / vinyl acetate copolymer having a vinyl acetate content of 18% and a melt index of 140 are mixed together with 77 parts of a polyisobutylene having a molecular weight of 900 at the temperature of 140 C in a pallet mixer, the ethylene / vinyl acetate copolymer being introduced in the form of granules. With 3 kgs of polymers at 300 rpm, the melting of the ethylene / vinyl acetate granules in the polyisobutylene is

obtained in less than 1/4 hour.

  Maintaining this mixture of polymers for 15 days at a temperature of 135 ° C. shows perfect stability and conservation of the viscosity of

  departure. No settling is noted.

  This mixture is added to road bitumen (40/50) in proportions of 30% of the polymer mixture relative to the total weight of the composition. The polymer / bitumen mixture is produced in less than 1/4

  hour thanks to the paddle mixer.

  EXAMPLE 2 (comparative) 2% of ethylene / vinyl acetate copolymer with 18% of vinyl acetate and of melt index 140 are added to a bitumen of grade 40/50 (penetrability 41, softening point 56, Fraass point -9 ° C, penetration index +0.46 '. The softening point is brought to 60.5 ° C, the penetration index at +0.85 without modifying the Fraass point.

increased from 65 to 69.5 C.

  By adding 5% of polyisobutylene of molecular mass 900 to the same bitumen, this does not modify the softening point, lowers the Fraass point to -16 C and brings the penetration index to +0.5 and the interval

flatness at 70.5 C.

  By adding to the same bitumen a composition as defined in Example 1 based on the ethylene / vinyl acetate and polyisobutylene copolymer, 28% of ethylene / vinyl acetate copolymer and 72% of polyisobutylene, this composition being added at the right rate 7% in the bitumen composition, the softening point is brought to 580C, the Fraass point to -17 C, the penetration index at +1.2 and the interval of

plasticity at 75 C.

  The addition of the composition therefore makes it possible to improve the bituminous binder on all of these properties without increasing the constraints of use.

EXAMPLE 3

  A formulation containing 10 parts of polyisobutylene having a molecular weight of 900 and 3 parts of the ethylene / vinyl acetate copolymer having a vinyl acetate content of 18% and a melt index of 140 is prepared and introduced into 87

  parts of bitumen 40/50 as cue defined above.

  The following viscosities are noted: at 140 C: 722mFa.s._ 160 C: 297mPa.s; , at 1800C 142mPa.s; while the base biture has the following viscosities: at 140 C 60OmPa.sa at 1600C: 263mPa.s at 1800C: 142 mPa.s, It can be seen that the combination of the invention makes it possible to slightly increase the viscosity at

  hot and improves the maneuverability of the mix.

  This is observed in the isalleent press test.

  Roundabout of the Laboratory of Bridges and Roads, on a mix 0/14 discontinuous of f.cr.ule / 14 porphyry:% 6/10 porphyry: 31% 0/2 porphyry: 39% limestones: 4% content of binder: 7 , 7 ppc (parts by weight

per hundred parts of aggregates).

  The asphalt 0/14 with the polymer binder forming the invention reaches: 89.5 of compactness at 10 gyrations 92.0 of compactness at 20 gyrations

, 0 compactness at 50 gyrations.

  The binder thus prepared also exhibits characteristics of resistance to the fatigue test and of resistance to deenrcbacze Far I water c_ aansivicé

also improved.

  A fatigue test is carried out, according to the method of LCPC (Central Laboratory of Bridges and Roads) in sinusoidal bending with constant deformation of trapezoidal specimens, obtained from coated sheets manufactured and compacted according to the procedures of Laboratories of Bridges and Pavements, on coated materials with the following formula: 6/10 La Noubleau 33% 2 / 6.3 La Noubleau 24% 0/2 La Noubleau 40.7% Limestone filler 2.3%

Binder 5.75 ppc.

  The following figures are obtained at the frequency of 25 Hertz and at 10C: at 106 cycles, the relative deformation is: 1.40.10-4 for the reference mix (binder / 50), but 2.20.10-4 for mix with binder

bitumen-polymer defined above.

  at 105 cycles, the relative deformation is: 2.10-4 for the reference mix; and of

  3.10-4 for asphalt mix with bitumen binder-

  polymer. There is therefore a larger admissible deformation for the same fatigue test time for the asphalt comprising the polymer binder according to the invention. In the water coating test, this property is demonstrated by the resistance ratio at 18 C in the DURIEZ simple compression test (or LCPC) with storage in immersion in water for 7 days compared at the concentration at

also dry for 7 days.

  By taking the following mix formula: / 14 La Noubleau 69% 0/2 La Noubleau 27.5% Limestone filler 3.5% Binder content 5.5 ppc the resistance ratio is 0.88 for the mix of reference in 40/50 against 0, 96 for the mix with bitumen-polymer binder as defined above.

Claims (7)

  1. Process for the preparation of a binder based on bitumen and polymers, characterized in that a mixture prepared beforehand, comprising an ethylene / vinyl acetate copolymer and a polyisobutylene having a weight, is added to a bitumen molecular understood between 400 and 1000.   2. Method according to claim 1, characterized in that the ethylene / vinyl acetate copolymer is a copolymer comprising at 45% by weight of vinyl acetate unit and a   fluidity index between 0.1 and 600.   3. Method according to claim 1 or 2, characterized in that the mixture of polymers is   performed in polyisobutylene / ethylene-   vinyl acetate between 90/10 and 50/50.   4. Method according to any one of   Claims 1 to 3, characterized in that   adds the composition comprising the vinyl acetate / ethylene copolymer and the polyisobutylene in proportions of 1 to 35% relative to the total weight of the composition.   5. Method according to any one of   claims 1 to 4, characterized in that one   prepares the bitumen-polymer binder directly on site by mixing the polymer-based and bitumen-based composition in times of less than 1/4 hour. 6. Composition intended to be used in the process as defined in any one of   Claims 1 to 5, characterized in that it   is prepared by gradual addition of granules of ethylene / vinyl acetate copolymers in polyisobutylene at a temperature slightly higher than the dissolution temperature of the ethylene / vinyl acetate copolymer in polyisobutylene liquid by mixing.   7. A method of producing a road surface, characterized in that a composition containing a mixture of ethylene / vinyl acetate and polyisobutylene copolymers with a molecular weight of between 400 and 1000 is added just before use. bitumen and after complete mixing,   applies said composition as a road surface.