CA1106527A - Polymer modified bitumen - Google Patents
Polymer modified bitumenInfo
- Publication number
- CA1106527A CA1106527A CA330,715A CA330715A CA1106527A CA 1106527 A CA1106527 A CA 1106527A CA 330715 A CA330715 A CA 330715A CA 1106527 A CA1106527 A CA 1106527A
- Authority
- CA
- Canada
- Prior art keywords
- bitumen
- modified bitumen
- weight
- venezualan
- copolymer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Compositions Of Macromolecular Compounds (AREA)
Abstract
A B S T R A C T
The invention provides a polymer-modified bitumen comprising Venezualan feed stock bitumen and tetrachain radial teleblock polybutadiene/
polystyrene copolymer of at least 100,000 molecular weight. The components can be readily blended to increase the softening point of the bitumen without undue increase in melt viscosity to give a product of good low temperature flexibility. The proportion of co-polymer, based on the total polymer/bitumen mix, is suitably 10-14 weight %. The copolymers of higher molecular weight, e.g. 180,000, give the best increase in softening point and low temperature flexibility, but for ready blending in the bitumen may need to be fluxed with lube oil also from Venezualan feed stock. The modified bitumen, which can be in admixture with conventional fillers and additives, can be provided as a calendered sheet, or as a coating bitumen or an expansion joint compound .
The invention provides a polymer-modified bitumen comprising Venezualan feed stock bitumen and tetrachain radial teleblock polybutadiene/
polystyrene copolymer of at least 100,000 molecular weight. The components can be readily blended to increase the softening point of the bitumen without undue increase in melt viscosity to give a product of good low temperature flexibility. The proportion of co-polymer, based on the total polymer/bitumen mix, is suitably 10-14 weight %. The copolymers of higher molecular weight, e.g. 180,000, give the best increase in softening point and low temperature flexibility, but for ready blending in the bitumen may need to be fluxed with lube oil also from Venezualan feed stock. The modified bitumen, which can be in admixture with conventional fillers and additives, can be provided as a calendered sheet, or as a coating bitumen or an expansion joint compound .
Description
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This invention relates to bitumen/polymer compositions especially ~hose suitable for use in the formation o~ weatherproof roofing felt.
Tetrachain radial teleblock polybutadiene/polystyrene copol~ymers i~volve intersecting polybutadiene chains terminated at each end with ; 5 ~ polystyrene blocks; the terminal polystyrene blocks of different molecules tend to associate into micelles and form with the intersecting polybutadiene chains a network structure, so that the copolymers are ~imilar in structure and behaviour to vulcanised rubber, but without vulcanisation.
~hese copolymers tend to improve the rheological and other properties of bitumen~ It is particularly desirable to increase the sotening point of bitumen whilst retaining or obtaining good low te~perature flexibility. Difficulty has been encountered, however, in obtaining the desired degree of improvement without undue increase in melt viscosity and without problems in dispersing the copolymer in the bitumen.
According to the invention we ha~e found that the tet~achain ~! ' xadial teleblock copolymer used should ha~e a lecular welght of - . loo,ooo at least,~e.g. inherent viscosity of about O.9S or more THF, .,~ . .
0.002 g/ml) and that the bitumen with which it is mixed should be or comprise one obtained from Vene~ualan crude; a satisfactory product . . ,", ~ ~ .
~,, ,.,...... ~ , .
.
,' ~ , '.
softenlng point and low-tem~erature flexibilit~ are then obtainable. A
said copolymer content of at least S wt.% ~based on the total weight o~
poly~er and bitumen ln the composition) is usually necessary to give appreciable improvement in the mentioned properties, whilst one of more S than 15 wt.~ may be uneconomic at present and/or give a composltion of too high a melt viscosity; a currently preferred range ~or the said copolymer content is from 9 to 15 ~e.g. 10 to 14) wt.%, according to the identity of the copolymer(s) used.
With copolymers at the lower end of the ~entioned molecular weight range, homogeneous dispersal in the bitumen can be achieved sufficiently readily at temperatures below that at which copolymer degradation occurs. The copolymers of higher molecular weight, e.g.
about 180,000, inherent viscosity ~THF, 0.002 g/ml) about 1.50, give better increase in softening point and low-temperature flexibility but lS are more difflcult to disperse homogeneously in bitumen at acceptable temperatures. For such higher molecular weight copolymers it is ~ advantageous for the Venezualan bitumen to be one fluxed with lube oil ; also from Venezualan crude; addition of as little as 2 wt.~ of such lube oil to the bitumen appreciably reduces the mixing time necessary for homogeneous dispersal of the copolymer therein. Sultably the - Venezualan bitumen used with the higher M.W. copolymers is, for example, a 300 pen bitumen made by fluxing a harder grade with lube oil (e.g.
~50 sec lube oil) from ~optionally the same) Venezualan crude.
The polymer-modified bitumens obtained according to the invention, incorporating if desired at least one o~ particulate and fibrous fillers, pigments, and flame retardants etc., can usually be compounded and calendered into sheets; the low-temperature flexibility of such sheets, ~oupled with high softening point which prevents their undue softening at summer temperatures, sults such sheets well for use as weatherproof .~
. .
' , ~.
S~7 roofing felt.
Suitable tetrachain radial teleblock coEtolymers ~or use in ~e lnvention include "Solprene" ~Trade ~ark) 415 and 411 from Phillips Petroleum Company, the ~ormer having a 60i40 B/S ratio and an inherent S viscosity ~T~lF, 0.002 g/ml) of 0.95, the latter a 70/30 B/S xatio and an inherent viscosity of 1.50.
The invention is illustxated by the following specific example~.
EX~MPLES 1 to 7~
nSolprene" 415 was mixed into Venezualan crude bitumens at a temperature of 160 to 180 C with propeller-type stirrers. The so~tening point ~SP) o~ the bitumen was taken before the addition of copolymer, and the 5P and low temperature flexibility of the homogeneous product were noted. The percentage of added copolymer in the following results table is based on the weight o~ the total mixture.
...... ..... ............
. .__ _ _ .
15 EXAMPLE % COPOLYMER BITUME~ S.P.BEFORE S.P.AFTER FLEXIBILITY AT
_ ._ ~ _ (1) 10% By Wt. 200 pen 36C 89C Satisfactoxy (2) 12~ By Wt. 200 pen 36 & 96C Good (3~ 13% By Wt. 200 pen 36C 98 C Excellent (4) 14~ By Wt. 200 pen 36 C 105 C Excellent (5) 13% By Wt. 100 pen _ 105-107 C Good but not as good as (4) ~6) 14~ By Wt. 40 pen _ 112 C Good but not as (7r l 6~ywt 1200EenL36C l 70c ~gtl 5e~
''.:, '`" . ~ ' ~ EX~PLE 8 ~: .
"Solprene" 411 was mixed, as in Examples 1 to 7, with 300 pen bitumen made by 1u~ing a hardex yrade with 150 see lube oil ~rom the , ' ~
., j ' '' ~ - , , ' :
, _ 5 _ ~ .
same Ve~azualall cr~de. It was fo md that the 411 could be propeller mixed completely into this bitumen in under one hour. At 13% copol~mer addition (bas~d on the weight of the whole mixture~ the SP of the bitumen was increased from 33 C to 105 C and flexibility at minus 30 C was excellent; the mix when cooled showed approximately 300~ extension with 100~ recovery.
Mixing "Solprene" 415 with the 300 pen bitumen of Example 8 gave a very similar final SP to that obtained by mixing the same proportion with the 200 pen bitumen of Examples 1 to 4, but low temperature flexibility was even better. At 13~ copolymer addition, the SP of the mlx was 98-99 C.
~ he invention shows that high molecular weight tetrachain radial teleblock copolymers o~ polybutadiene/polystyrene are soluble in the oil phase of Venezualan bitumens, e.g. at a loading of 10-14~ by wt. of the t3tal polymer~bitumen mix (90-86% bitumen) and that the highest molecular weight (and the most stable and effective) copolyme~scan be quickly and successfully incorporated in (e.g. a 300 pen) Venezualan feed stock bitumen that has been made by fluxing a harder-bitumen with lube oil from Venezualan crude. The resulting polymer modified bitumen can have rubber-like properties, but still be thermoplastic; at low temperatures it will ~tretch with recovery and be flexible in thin film yet will not soten unduly at summer temperatures. It will show less tendency than unmodified bitumen to flow and sag at temperatures near to its SP, and it will sta~d a considerable addition of inert filler, e.g. up to 25% by weight without loss of flexibllity. By means of the invention it is possible ~o make a coating bitumen - or, with a lit~le modification, an expan~ion ~olnt compound - with good properties containing only 10-11% polymer in the ~inal mix; this is because of the discovery that the really high :' ,,'...................... ` ' . .
'' , . ., .
.
s~
molecular weight copolymers easil~ dissolve in the bitumen ~luxed ~e.g.
to 300 pen) with lQb~ o~l:irom Venesu~lan soQrcc C~Q'~.
`
'' :
, .~ , , ', , . ' :
:, . .
:; , ~' . , , . . . . .
;
' , , .
' .~ , , .
~, :
~ _ .
``.' ' . ~ ` ' ,:
, .
, : ~ ; , : .. ' :
'~ ' . ~':
This invention relates to bitumen/polymer compositions especially ~hose suitable for use in the formation o~ weatherproof roofing felt.
Tetrachain radial teleblock polybutadiene/polystyrene copol~ymers i~volve intersecting polybutadiene chains terminated at each end with ; 5 ~ polystyrene blocks; the terminal polystyrene blocks of different molecules tend to associate into micelles and form with the intersecting polybutadiene chains a network structure, so that the copolymers are ~imilar in structure and behaviour to vulcanised rubber, but without vulcanisation.
~hese copolymers tend to improve the rheological and other properties of bitumen~ It is particularly desirable to increase the sotening point of bitumen whilst retaining or obtaining good low te~perature flexibility. Difficulty has been encountered, however, in obtaining the desired degree of improvement without undue increase in melt viscosity and without problems in dispersing the copolymer in the bitumen.
According to the invention we ha~e found that the tet~achain ~! ' xadial teleblock copolymer used should ha~e a lecular welght of - . loo,ooo at least,~e.g. inherent viscosity of about O.9S or more THF, .,~ . .
0.002 g/ml) and that the bitumen with which it is mixed should be or comprise one obtained from Vene~ualan crude; a satisfactory product . . ,", ~ ~ .
~,, ,.,...... ~ , .
.
,' ~ , '.
softenlng point and low-tem~erature flexibilit~ are then obtainable. A
said copolymer content of at least S wt.% ~based on the total weight o~
poly~er and bitumen ln the composition) is usually necessary to give appreciable improvement in the mentioned properties, whilst one of more S than 15 wt.~ may be uneconomic at present and/or give a composltion of too high a melt viscosity; a currently preferred range ~or the said copolymer content is from 9 to 15 ~e.g. 10 to 14) wt.%, according to the identity of the copolymer(s) used.
With copolymers at the lower end of the ~entioned molecular weight range, homogeneous dispersal in the bitumen can be achieved sufficiently readily at temperatures below that at which copolymer degradation occurs. The copolymers of higher molecular weight, e.g.
about 180,000, inherent viscosity ~THF, 0.002 g/ml) about 1.50, give better increase in softening point and low-temperature flexibility but lS are more difflcult to disperse homogeneously in bitumen at acceptable temperatures. For such higher molecular weight copolymers it is ~ advantageous for the Venezualan bitumen to be one fluxed with lube oil ; also from Venezualan crude; addition of as little as 2 wt.~ of such lube oil to the bitumen appreciably reduces the mixing time necessary for homogeneous dispersal of the copolymer therein. Sultably the - Venezualan bitumen used with the higher M.W. copolymers is, for example, a 300 pen bitumen made by fluxing a harder grade with lube oil (e.g.
~50 sec lube oil) from ~optionally the same) Venezualan crude.
The polymer-modified bitumens obtained according to the invention, incorporating if desired at least one o~ particulate and fibrous fillers, pigments, and flame retardants etc., can usually be compounded and calendered into sheets; the low-temperature flexibility of such sheets, ~oupled with high softening point which prevents their undue softening at summer temperatures, sults such sheets well for use as weatherproof .~
. .
' , ~.
S~7 roofing felt.
Suitable tetrachain radial teleblock coEtolymers ~or use in ~e lnvention include "Solprene" ~Trade ~ark) 415 and 411 from Phillips Petroleum Company, the ~ormer having a 60i40 B/S ratio and an inherent S viscosity ~T~lF, 0.002 g/ml) of 0.95, the latter a 70/30 B/S xatio and an inherent viscosity of 1.50.
The invention is illustxated by the following specific example~.
EX~MPLES 1 to 7~
nSolprene" 415 was mixed into Venezualan crude bitumens at a temperature of 160 to 180 C with propeller-type stirrers. The so~tening point ~SP) o~ the bitumen was taken before the addition of copolymer, and the 5P and low temperature flexibility of the homogeneous product were noted. The percentage of added copolymer in the following results table is based on the weight o~ the total mixture.
...... ..... ............
. .__ _ _ .
15 EXAMPLE % COPOLYMER BITUME~ S.P.BEFORE S.P.AFTER FLEXIBILITY AT
_ ._ ~ _ (1) 10% By Wt. 200 pen 36C 89C Satisfactoxy (2) 12~ By Wt. 200 pen 36 & 96C Good (3~ 13% By Wt. 200 pen 36C 98 C Excellent (4) 14~ By Wt. 200 pen 36 C 105 C Excellent (5) 13% By Wt. 100 pen _ 105-107 C Good but not as good as (4) ~6) 14~ By Wt. 40 pen _ 112 C Good but not as (7r l 6~ywt 1200EenL36C l 70c ~gtl 5e~
''.:, '`" . ~ ' ~ EX~PLE 8 ~: .
"Solprene" 411 was mixed, as in Examples 1 to 7, with 300 pen bitumen made by 1u~ing a hardex yrade with 150 see lube oil ~rom the , ' ~
., j ' '' ~ - , , ' :
, _ 5 _ ~ .
same Ve~azualall cr~de. It was fo md that the 411 could be propeller mixed completely into this bitumen in under one hour. At 13% copol~mer addition (bas~d on the weight of the whole mixture~ the SP of the bitumen was increased from 33 C to 105 C and flexibility at minus 30 C was excellent; the mix when cooled showed approximately 300~ extension with 100~ recovery.
Mixing "Solprene" 415 with the 300 pen bitumen of Example 8 gave a very similar final SP to that obtained by mixing the same proportion with the 200 pen bitumen of Examples 1 to 4, but low temperature flexibility was even better. At 13~ copolymer addition, the SP of the mlx was 98-99 C.
~ he invention shows that high molecular weight tetrachain radial teleblock copolymers o~ polybutadiene/polystyrene are soluble in the oil phase of Venezualan bitumens, e.g. at a loading of 10-14~ by wt. of the t3tal polymer~bitumen mix (90-86% bitumen) and that the highest molecular weight (and the most stable and effective) copolyme~scan be quickly and successfully incorporated in (e.g. a 300 pen) Venezualan feed stock bitumen that has been made by fluxing a harder-bitumen with lube oil from Venezualan crude. The resulting polymer modified bitumen can have rubber-like properties, but still be thermoplastic; at low temperatures it will ~tretch with recovery and be flexible in thin film yet will not soten unduly at summer temperatures. It will show less tendency than unmodified bitumen to flow and sag at temperatures near to its SP, and it will sta~d a considerable addition of inert filler, e.g. up to 25% by weight without loss of flexibllity. By means of the invention it is possible ~o make a coating bitumen - or, with a lit~le modification, an expan~ion ~olnt compound - with good properties containing only 10-11% polymer in the ~inal mix; this is because of the discovery that the really high :' ,,'...................... ` ' . .
'' , . ., .
.
s~
molecular weight copolymers easil~ dissolve in the bitumen ~luxed ~e.g.
to 300 pen) with lQb~ o~l:irom Venesu~lan soQrcc C~Q'~.
`
'' :
, .~ , , ', , . ' :
:, . .
:; , ~' . , , . . . . .
;
' , , .
' .~ , , .
~, :
~ _ .
``.' ' . ~ ` ' ,:
, .
, : ~ ; , : .. ' :
Claims (14)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A polymer-modified bitumen comprising Venezualan feed stock bitumen and tetrachain radial teleblock polybutadiene/
polystyrene copolymer having intersecting polybutadiene chains terminated at each end with polystyrene blocks, the terminal polystyrene blocks of different molecules being associated into micelles and forming with the intersecting polybutadiene chains a network structure, the copolymer being of at least 100,000 molecular weight.
polystyrene copolymer having intersecting polybutadiene chains terminated at each end with polystyrene blocks, the terminal polystyrene blocks of different molecules being associated into micelles and forming with the intersecting polybutadiene chains a network structure, the copolymer being of at least 100,000 molecular weight.
2. A modified bitumen according to claim 1 containing at most 15 weight % of said copolymer based on the total weight of polymer and bitumen.
3. A modified bitumen according to claim 1 containing at least 5 weight % of said copolymer based on the total weight of polymer and bitumen.
4. A modified bitumen according to claims 2 and 3 containing from 9 to 15 weight % of said copolymer based on the total weight of polymer and bitumen.
5. A modified bitumen according to claim 1 containing from 10 to 14 weight % of said copolymer based on the total weight of polymer and bitumen.
6. A modified bitumen according to claim 1 wherein Venezualan feed stock bitumen is one fluxed with Venezualan feed stock lube oil.
7. A modified bitumen according to claim 6 wherein the Venezualan feed stock bitumen is a 300 pen bitumen made by fluxing a harder grade with Venezualan feed stock lube oil.
8. A modified bitumen according to claim 7 wherein the lube oil is 150 sec lube oil.
9. A modified bitumen according to claim 6 wherein the amount of lube oil, based on the Venezualan feed stock bitumen, is at least 2 weight %.
10. A modified bitumen according to claim 6 wherein the copolymer has a molecular weight of about 180,000.
11. A modified bitumen according to claim 6 wherein the copolymer has a butadiene/styrene molar ratio of about 70/30 and an inherent viscosity (tetrahydrofuran, 0.002 g/ml) of about 1.5.
12. A modified bitumen according to claim 6 wherein the copolymer has a butadiene/styrene molar ratio of about 60/40 and an inherent viscosity(tetrahydrofuran, 0.002 g/ml) of about 0.95.
13. A modified bitumen according to claim 1 in admixture with at least one additive selected from particulate and fibrous fillers, pigments and flame-retardants.
14. A modified bitumen according to claim 1 in admixture with up to 25 weight % of inert filler.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA330,715A CA1106527A (en) | 1979-06-27 | 1979-06-27 | Polymer modified bitumen |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA330,715A CA1106527A (en) | 1979-06-27 | 1979-06-27 | Polymer modified bitumen |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1106527A true CA1106527A (en) | 1981-08-04 |
Family
ID=4114563
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA330,715A Expired CA1106527A (en) | 1979-06-27 | 1979-06-27 | Polymer modified bitumen |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1106527A (en) |
-
1979
- 1979-06-27 CA CA330,715A patent/CA1106527A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |