SE437529B - PROCEDURE FOR PREPARING BITUMEN-POLYMER COMPOSITIONS - Google Patents

Description

79o92eo-7 2 creates in the cold state, while in the product formed a viscosity in the hot state is maintained, which is substantially identical to the viscosity of a bitumen product on the basis of a two-block polymer composed of polystyrene and polybutadiene.

The reason for these improvements may be a double crosslinking, which arises between polymer chains. The one crosslinkable, which is reversible, is provided by the carboxyl groups of the polymer, which undergo salt-forming reactions with metal ions (Fe, Ni, V) contained in the bitumen when the temperature of the mixture drops; in this case, the non-elastomeric two-segment chains are converted into elastomeric polysegment chains. The second crosslinking, which is irreversible, is accomplished by covalent sulfur bridges. These sulfur bridges formed between polymer chains remain intact at elevated temperatures.

As the elastomeric properties of bitumen are improved thanks to the double crosslinking, it is possible to reduce the polymer content of the product, so as to obtain properties which are simply and sufficiently sufficient to meet the specifications for the intended use; the actual price of the product can thus be directly affected.

The reversibility of the ionic crosslinking reaction facilitates the use of the product in the hot state, while maintaining a viscosity which is identical to that obtained using an equal amount of two-block polymer without carboxyl groups.

The following examples show how the properties can be improved by adding a copolymer of styrene and carboxylated butadiene.

Example I. A) 100 parts of a bitumen 80-100 with softening temperature 48 ° C (determined according to test with ball and ring) and breaking point according to Fraass amounting to -18 ° C are mixed with b) 10 parts of isoprene-styrene-two-block polymer with average molecular weight 80,000 and with a ratio of isoprene: styrene amounting to 3. The mixture is kept for 3 hours and 30 minutes at 170 ° C with stirring, after which 790 9 2 6 0: - 7 are added 0.2 parts of elemental sulfur and the stirring is continued for another 1/2 hour. The properties of the bitumen polymer product obtained are given in the table below.

Example II. Example I is repeated omitting the sulfur addition and for 4 hours. stirring the mixture. This composition turns out to be brittle (brittle) in the drawing attempts from 1D mm / min. at -10 ° C.

Example III. The procedure is the same as in Example I, but the isoprene block in the two-block polymer is replaced with a block of carboxylated butadiene. This improves the elastic properties, as shown in the table below.

Example IV. This example is to be compared with Example III. It is carried out in the same way as Example III but without vulcanization in situ, ie. the addition of elemental sulfur is omitted. In this case, the brittleness is manifested in the 500 mm / min performed at -10 ° C. drawing attempts.

Example V. In view of the fact that the use of carboxylated butadiene in the end positions of the chains has given improved results in terms of the elastic properties, the same procedure is chosen in this example as in the previous examples but with a smaller amount of copolymer: only 3 %.

Example VI. This example is carried out as a comparative example of Example V, in which case work is carried out using 3% of a copolymer formed of styrene and non-carboxylated butadiene.

Products of the type obtained within the scope of the present invention have very pronounced elastic properties and exhibit a significant range of plasticity. Due to this, they can have very useful use properties, for example when used for a) pavements and industrial pavements (coatings, coatings, pavers); b) s.k. industrial applications, for example, the manufacture of seals or waterproof products (coatings, asphalt mats, roofing materials, paints, undercarriages for car bodies, materials for thermal insulation, electrical insulation or sound insulation). 7909260-7 vw fl om fi mw mcmnx fi øonm> m unøhw mm m fl anwë hm wc fl npmë üww fl w »um mmw> m Qwvnm> nwwmww pmm uma fl mum w ^ 1v xomhum fl mä 1 1 1 1 oom m.mH wm o>. ~ HN1 m.> M oo H> M 1 1 1 1 .nom nw ~ om w.æH oom om> mo: .A NN1 Ho om> Û 1 1 1 1 o fi m on m.o fl o.mH oom om w @ .H wm Hm1 fi o fi mn> HM oom mm fl mo? Hm. oo »om mäm oH oom oow mmš mmå m.æm1 om fi om HHH V 1 1 1 1 1! 1 1 oom mm mmd nmš 1 nm1 m »o: HH _ om æn ndm wšm omm oom w md mmm ooH SÅ ïäw .H1 mït. mm H .w vw LL »1.1,“ w w u »wo J .J .H vb R R mmm non & R hun han & .1 R \ nmn hmm. > Awn fi h to zoo .sdíss oom .ooof .øëise oH 8.03 .. .nëiss oom .ooom + .mwåmm men: mo? 1 um flflfl m oo.uxm 1wMM% xwmnxwmws fl cwm fi m wxau fi hm 1Gx3nE Hamßmñ

Claims (3)

7909260-7 P a t e n t k r a v A process for preparing bitumen-polymer compositions, wherein at a temperature of 130-230 ° C with stirring, 80-98% by weight of a bitumen with a penetration of 30-220 and 2-20% by weight of block polymer with a medium molecular weight are mixed. weight of 30,000 - 300,000, which block polymer is a copolymer of styrene and conjugated diene, and this mixture is kept for at least 2 hours at said temperature and then 0.1 - 3% elemental sulfur, based on the bitumen, is added while maintaining of the same stirring and temperature conditions for at least 20 minutes, characterized in that the segment formed by conjugated diene is formed of carboxylated butadiene. Process according to Claim 1, characterized in that the copolymer added to the bitumen is a two-block polymer composed of polystyrene and carboxylated polybutadiene, the polystyrene content preferably being 15 to 25%, the molecular weight preferably amounting to 70,000 to 90,000 and the content of carboxyl groups. , based on the polymer, is 0.05 - 0.1%. Use of bitumen-polymer compositions obtained by the process according to claim 1 or 2 for road coatings and coatings on industrial products or materials and for the production of seals or waterproof products.