AU615741B2

AU615741B2 - Asphalt composition for waterproof sheets

Info

Publication number: AU615741B2
Application number: AU34007/89A
Authority: AU
Inventors: Iwao Tsurutani
Original assignee: Ube Industries Ltd
Current assignee: Ube Corp
Priority date: 1988-05-09
Filing date: 1989-05-03
Publication date: 1991-10-10
Anticipated expiration: 2009-05-03
Also published as: AU3400789A; JPH0747670B2; KR890017317A; KR950011920B1; JPH01282235A

Description

A UST R AL I A PATENTS ACT COMPLETE SPECIFICATION 6 1 3 7 41A OR I GINAL (FOR OFFICE USE) ClIas S nt ClIass L Application Number: Lodged: 2 Complete Specification Lodged: Accepted: Publ ished: Pr Ior ity: Related Art: Name of Appl icant ,,,AJBEI,N~DUSTR,IES,_LD Address of App!lIcant h2., i honmachI I -chone Ub *49114 a 9, y c h I Ja4,4p AculInventor(s) 4,a Address for Service: PATENT ATTORNEY SERVICES 26 Ellingworth Parade, POX Hil1l, VictOria 3128 Complete, specification for the Invention entitled: Asphalt Composition for waterproof sheets The following statement is a full description of this invention, Including the best method of performing it known to us V Measured in~ accor'dance with JTS' X 2207.

I 1 Title of the Invention Asphalt Composition for Waterproof Sheets Background of the Invention and Related Art Statement The present invention relates to an asphalt composition for waterproof sheets which comprises, as essential components, an amorphous propylene-ethylene random copolymer or an amorphous propylene-butene-1 random copolymer and asphalt.

The asphalt composition for waterproof sheets according to the present invention is inexpensive and has excellent properties. Accordingly, it is extensively used, for example, as a sealing material for filling gaps between concrete slabs used in buildings, railways, roads, etc., a sealing material for joining waterway tubes, etc. and a is 15 waterproof material for roofs, and is particularly suitable for use in waterproof sheets applied by a torch method.

As asphalt-based waterproof compositions, there are *known those obtained by incorporating into asphalt a crude rubber natural rubber, butyl rubber, styrenebutadiene-styrene rubber, thermoplastic elastomer), a resin atactic polypropylene, petroleum resin), etc.

In page 112 of 1986 Nov. issue of "The Bosui Journal", in particular, there is a description on a torch application method for waterproof sheets in which the backside of a single ply waterproof sheet (thickness: about 4 mm) i'or i 1 3 1 roofs and a founda-ion onto which the sheet is to be applied are simultaneously heated by a torch-shaped gas burner to momentarily laminate the sheet to the foundation, as well as on a waterproof sheet suitable for said torch application method. The description includes cases of adding to asphalt an atactic polypropylene or a styrene-butadiene-styrene block copolymer to modify asphalt.

These known compositions, however, have problems in, for example, change in properties due to temperature difference in summer and winter, recoverability of s deformation, and workability due to viscosity change during operation.

With respect to the waterproof sheets for torch application method, the modified waterproof sheet obtained

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by adding to asphalt a styrene-butadiene-styrene block copolymer (SBS) has problems of difficult mixing of asphalt and SBS an too high viscosity of the mixture, making it difficult to add SBS in a large amount; therefore, the sheet softens significantly at high temperatures (although its low temperature flexibility is superior even at a small addition of SBS), making it difficult to utilize at tropical or subtropical regions. Meanwhile in the modified waterproof sheet obtained by adding an atactic polypropylene to asphalt, it is possible to add the atactic polypropylene in a large amount although the resulting waterproof sheet gives only slight softening at high temperatures. This atactic polypropylene is an amorphous polymer of low molecular weight obtained as a by-product in production of a crystalline isotactic polypropylene, has a low viscosity, and is inexpensive because it is a by-product. Therefore, the atactic polypropylene has been used in waterproof sheets for torch application method; however, it has problems as follows.

That is, there are three kinds of crystalline isotactic polypropylenes, i.e. a homopolymer, a random copolymer and a S* block copolymer. The homopolymer consists only of propylene. The random copolymer contains ethylene, even if ethylene is copolymerized, in an amount of up to about resultantly, the atactic polypropylene as a by-product also contains ethylene in an amount of up to about 5-6%.

Thus, the atactic polypropylene obtained as a byproduct in production of a homopolypropylene or a random S polypropylene contains propylene as a major component, and accordingly it has been difficult to obtain an atactic polypropylene having good low temperature properties.

S Meanwhile, the amorphous polypropylene obtained as a by- Sproduct in production of a block polypropylene, although it contains a large amount of ethylene in its extractable rubber component, is not a random copolymer and accordingly has no uniform composition, is sticky and has no uniform 3 quality, making the utility low.

For the above reasons, it has been difficult to obtain an atactic polypropylene having good low temperature properties and high utility.

Since the atactic polypropylene is a by-product, it has been difficult to obtain an atactic polypropylene of d :iired properties in viscosity, scztening point, hardness, etc. in a required amount. Since the molecular weight of the atactic polypropylene obtained as a by-product varies depending upon the molecular weight of the crystalline S isotactic polypropylene obtained as a product, it has been impossible to obtain an atactic polypropylene of desired melt viscosity. Since a solvent is used at the time of separation of the atactic polypropylene (a by-product) from the cyrstalline isotactic polypropylene (a product), the complete removal of the solvent has been difficult, and the removal of the remaining catalyst has also been difficult.

S Moreover, as the activity of catalyst for isotactic polypropylene production has been increased, the amount of the atactic polypropylene produced as a by-product has Sdecreased; therefore, the stable supply of the atactic polypropylene in the future is questionable.

The waterproof sheets comprising, as a main modifier, the atactic polypropylene having the above problems, have various drawbacks in that having poor low temperature i CI~" flexibility, they tend to form cracks when applied or used at low temperatures, they have an odor and a fear of inflammation, both caused by the remaining solvent, and it is difficult to obtain them so as to have a desired softening point and a desired melt viscosity. Further, with these waterproof sheets, there may be the termination of the production in the future because the stable supply of the raw material is questionable.

i Objects and Summary of the Invention Therefore, the object of the present invention is to i provide an asphalt composition for waterproof sheets which is I free from the above-mentioned drawbacks of the known waterproof compositions, which is superior particularly in low temperature i flexibility, heat resistance, workability and quality stability, 15 and which is particularly suitable for use in waterproof sheets applied by a torch method.

According to the present invention there is provided an asphalt composition for waterproof sheets, comprising 100 parts by weight of an amorphous propylene-ethylene random 20 copolymer having an ethylene content of 8-30% by weight, or i an amorphous propylene-butene-I random copolymer having a butene-l content of 10-60% by weight, both of which have a number-average molecular weight of 1,000-20,000 and a boiling n-heptane insoluble of 15% by weight or less when measured by soxhlet's extractor, and 100-1,900 parts by weight of asphalt.

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Detailed Description The amorphous propylene-ethylene random copolymer or amorphous propylene-butene-1 random copolymer used in the present invention can be obtained by introducing ethylene or 5 butene-1 into liquefied propylene and copolymerizing them in the presence of hydrogen using, for example, a titanium-onmagnesium chloride catalyst and triethylaluminum. This amorphous random copolymer has a number-average molecular weight of 1,000-20,000, preferably ',500-18,000, with the propylene-ethylene random copolymer having an ethylene Scontent of 8-30% by weight, preferably 9-28% by weight and the propylene-butene-1 random copolymer having a butene-1 content of 10-60% by weight. Unlike the atactic polypropylene obtained as a by-product, the above copolymer has an ethylene or butene-1 content of the above range; accordingly, it has good heat resistance possessed by the atactic polypropylene and yet good low temperature properties and can be produced so as to have desired properties in softening point, melt viscosity, etc, and to have stable quality. The copolymer can have a desired softening point and a desired melt viscosity by controlling the proportions of propylene and ethylene or butene-1 to be copolymerized as well as the molecular weight of copolymer to be produced. The above copolymerization uses no solvent and accordingly includes no solvent-related step;

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1 -1 Ilr a therefore, there is neither fear of inflammation nor odor problem.

In the present invention, when the number-average molecular weight of the random copolymer is smaller than 1,000, the modification of asphalt is insufficient; when the molecular weight is larger than 20,000, the random copolymer has too high a melt viscosity, making its mixing with asphalt difficult.

when the ethylene content of the amorphous propylene-ethylene random copolymer is less than the resulting composition has no sufficient improvement in low temperature properties; when the ethylene content is more than 30%, the composition is too soft at normal temperature or has too low a softening point, making the composition unusable for high temperature applications where heat resistance is required.

15 It is preferable that the amorphous propylene-ethylene random copolymer or amorphous propylene-butene-l random copo)'mer be amorphous in such arn ext~nt as to give no endothermic peak due to melting of crystal when subjected to measurement of temperature elevation by differential scanning 20 calorimeter and also to give a boiling n-heptane insoluble of 15% by weight or less when measured by Soxhlet's extractor. A crystalline propylene-ethylene random copolymer or propylene-butene-1 random copolymer is not preferable, because, when mixed with asphalt, they do not give a uniform mixture.

The asphalt referred to in the present invention can be straight asphalt or blown asphalt. However, straight asphalt is preferred in view of the better compatibility with the amorphous propilene-ethylene random copolymer or amorphous propylene-butene-1 random copolymer and the lower 7 V k s C __i cost. The straight asphalt referred to herein is an asphalt specified by JIS K 2207 and having a softening point of 0 C, preferably 35-80 0

C.

The compounding proportions of the two components in the present composition are 100 parts by weight of the amorphous propylene-ethylene random copolymer or amorphous propylenebutene-1 random copolymer and 100-1,900 parts by weight, preferably 120-1,600 parts by weight of asphalt. When the asphalt proportion is less than 100 parts by weight, the asphalt amount is too small and the resulting composition is S inferior in water proofness and cost (asphalt excels in these properties) as well as in workability. When the asphalt proportion is more than 1,900 parts by weight, the composition has poor low temperature properties.

The composition of the present invention can comprise, as necessary, at least one of synthetic rubbers, polyolefins and thermoplastic elastomers.

The incorporation of these polymers into the composition can increase the impact resistance of the 2G waterproof sheet produced with the composition. However, S the polymers are added in an amount of preferably 20 parts by weight or less per 100 parts by weight of the composition consisting of asphalt and the amorphous propylene-ethylene random copolymer or amorphous propylene-butene-1 random copolymer, in view of the miscibility with asphalt and the fluidity of the waterproof sneet produced particularly for 8 ii;torch application method. When the polymers are added in too large an amount, their mixing with asphalt is difficult.

As the synthetic rubbers, there can be mentioned a styrene-butadiene copolymer rubber (SBR), an isoprene rubber S 5 a butadiene rubber a neoprene rubber (NPR), an ethylene-propylene copolymer rubber (EPR), an ethylenepropylene-diene rubber (EPDM), a butyl rubber, etc. As the tj polyolefin polymers, there can be mentioned a polyethylene, K a polypropylene, a polybutene and copolymers comprising 10 ethy3 ne as a main component, said copolymers being j copolymers between ethylene and at least one comonomer a. 0selected from olefins propylene, buteni, pentene, i hexene, heptene, octene), vinyl esters vinyl acetate, i vinyl propionate), unsaturated carboxylic acid esters (e.g.

methyl acrylate, ethyl acrylate, methyl methacrylatei ethyl methacrylate) and their ionomers.

As the thermoplastic elastomers, there can be mentioned Sa styrene-butadiene-styrene block copolymer (SBS), a styrene-isoprene-styrene block -opolymer (STS), a styrene.

ethylene-butylene-styrene block copolymer (SEBS), etc.

The asphalt composition of the present invention can further comprise, depending upon the application, an inorganic filler such as calcium carbonate, aluminum hydroxide, clay, talc or the like.

In the present invention, mixing o2 the amorphous i i J4 S ,I

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9i propylene-ethylene random copolymer or amorphous propylenebutene-1 random copolymer, asphalt and various additives can be effected in accordance with a conventionally known method. For example, it can be effected by heat-melting asphalt in a mixing kettle, then adding thereto an amorphous propylene-ethylene random copolymer or amorphous propylenebutene-1 random copolymer and, as necessary, additives, and mixing the- until they become a uniform mixture.

The asphalt composition of the present invention can be used as a waterproof sheet singly or by impregnating, .oating or press-bonding the composition into, on or to a roofing paper, a woven or unwoven cloth, a metallic thin plate or foil, etc.

As the roofing paper, there can be mentioned those made of an organic or inorganic material, such as asbestos felt, asbestos roofing, perforated felt and the like. As the woven or unwoven cloth, there can be mentioned those using inorganic or organic long or short fibers such as glass fiber, nylon fiber, vinylon fiber, polyester fiber, 20 cellulose fiber and the like, AS the metallic thin plate or Sfoil, there can be mentioned those of copper, iron, aluminum and the like.

The waterproof sheet made from the present asphalt composition is superior in waterproofness, moistur prevention, heat insulating property, acousbic property, buffer action, stretchability, electrical insulating i t !i

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tll~--yXICi- I-_ls it1 property, weather resistance, chemical resistance, heat resistance and low temperature flexibility and accordingly can be advantageously used in various applications, particularly as a roofing material applied by a torch method.

The thickness of the above waterproof sheet is 0.2-10 mm, preferably 0.5-8 mm, particularly preferably 1-6 mm.

V/ien the thickness is too small, the sheet has no sufficient waterproofness and, when the thickness is too large, the sheet is difficult to apply. When the sheet is a roofing material applied by a torch method, the sheet is laminated to the roof by heat-melting the backside of the sheet while unwinding the sheet; therefore, if the sheet is too thin, the sheet may be cut by melting, or if the sheet is too thick, unwinding and heating of the sheet cannot be effected simultaneously.

As explained above, the asphalt composition for waterproof sheets according to the present invention has the following advantageous effects.

9 *9 9 O 9 ft 1. The waterproof sheet made from the asphalt composition has improved low temperature flexibility and accordingly causes no cracking during application at low temperatures and also after application.

2. The amorphous propylone-ethylene random copolymer or amorphous propylene-bute*-1 random copolymer has good compatibility with asphalt and accordingly can be mixed with asphalt in a large amount. As a result, the composition can be free from softening and flowing at high tempE:.ratures.

3. The waterproof sheet made from the asphalt composition can have controlled properties in softening point, hardness, flui4dity, etc.

4. The composition has neither odor problem nor fear of inflammation owing to s')lvent, during its production, application and use.

Examples VI Q The present invention is explained in further detail ::below by way of Examples. Uiowevez, the present invention is 11eei no way restricted to these Examples, SExamples 1-8 and co 'mparative Examples 1-3 (Materials used] Amorphous tpropylene-ethyleniN random copol~ymers Rextacs produ~ced b1y V1L Paso Products Co.,I U.S.A.

**Number-average Ethylene 'Grade softLeningi. point, Penetration molecular weight content fl2A80 146 0 C 15 7,40 10I wt.% 13" f5A3$ 1270C 45 5, 900 20 Wt.% B5A80 127 0 C 45 7,300 2C0 Wt,% IL Amorphous propylene-buten.-1 random copolymer extac produced by El Paso Products Co., U.S.A.

Number-average Butene-1 Grade Softening point Penetration molecular weight content E4 1101C 30 6,700 40 wt.% Atactic polypropylene (by-product) Vistac L, produced by Chiba Fine Chemical K.K.

Softening point: 110 0

C

Melt viscosity: 500 (150 0

C)

Ethylene content: 0% Styrene-butadiene-styrene block copolymer CARTFL.X TR 1101 produced by Shell Chemical Asphalt Straight asphalt 80/100 produced by NIPPON OIL CO., LTDJ.

Compounding of compositions)l Asphal't was placed in a mixing vessel and heated to 10o wthstrring. Thrt eeadded an amorphous 0 propylene -ethylene random copolymer or amorphous propylene- *butene-1 random copolymner, an aati pyro e, an I styrene-buthadiene-styrene block copolymer in proportions as shown in Table I They were stirred for 30 minutes to obtain a composition. Each mixture was meast'.red fo)r P.roperties in accordance with the following methods. The results are shown in Table 1.

[Methods for moalsurement of properties] Ring and biall type softening point X- r -I Measure Penetration MeasurE 2207.

a d in accordance with JIS K 2207.

ed at 25 0 C and 40 0 C in accordance with JIS K Number-average molecular weight Measured in accordance with a GPC method at 135 0 C using a solvent (ODCB).

Ethylene content Measured in accordance with an NMR method.

Low temperature flexing property A composition was press-molded to obtain a sheet of 2 mm in thickness. The sheet was wound round a bar of 10 mm in diameter in pn atmosphere of -10 0 C to examine the ae S' *occurrence of breakage. The low temperature flexing property was expressed in terms of (number of samples which Scaused breakage)/(number of total samples tested).

Melt viscosity l* Measured in iccordance with JIS K 2207.

4 Table 1, Examplf.,s Comparative Examples 1 2 3 4 5 6 }7 81 2 3 Amorphous Propylene-ethylene random copolymer B2A80 100 B5A35 100 100 B5A8O 100 100 100 0 0, random copolymer 44 E4 100 1001 SAtactic Polypropylene 100 SStyrene-butadiene--styrene 81 block copolymer 15 80 100 0 -Straight asphalt 400 400 150 400 150 130'0 400 150 400 150 150 Softening point MC) 105 106 1201 110 133 102 80 95 74 111 No composition Penetration 2 5*C 77 75 57 70 26 80 55s 44 80 51 was obtained 44 (dim) Ibe,-Ruse uniform 0C40 0 *C 195 190 130 170 90 205 130 110 240 150 mixing &q (D-H materials 4.1 epeaur feHn 0710 0710 071 0 071 0 0710 0710 1710 07/10 10710 47/10 was ipossible-.

$4property MC) (Number of ad samples which caused/ Po breakage)/(Nuzber of total .0samples tested)

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Claims

1. An asphalt composition for waterproof sheets, comprising 100 parts by weight of an amorphous propylene-ethylene random copolymer having an ethylene content of 8-30% by weight, or an amorphous propylene-butene-1 random copolymer having a b-tene-1 content of 10-60% by weight, both of which have a number-average molecular weight of 1,000-20,000 and a boiling n-heptane insoluble of 15% by weight or less when measured by Soxhlet's extractor, and 100-1,900 parts by weight of asphalt.

2. An asphalt composition as claimed in Claim 1 and substantially as herein before described in the particular examples. i I e 15 Dated this 22nd day of July, 1991 PATENT ATTORNEY SERVICES Attorneys for UBE INDUSTRIES, LTD