DD294720A5 - POLYMOMODIFIED BITUMEN WITH IMPROVED ELASTIC BACKPACK - Google Patents

Abstract

The invention describes polymer-modified bituminous compositions having a content of 0.5 to 20 * of polymer constituents, wherein 20 to 100 * of the polymer additive is polyalkyl (meth) acrylate, which in proportions of 50 to 99.8 * from C8 to C26 alkyl (Meth) acrylates, in proportions of 0.1 to 2.8 * of polymerizable carboxylic acids and in proportions of 0.1 to 2.8 * of polymerizable basic nitrogen compounds is constructed. The bitumen-modified polyalkyl methacrylates have molecular weights of 30,000. By this modification, bituminous mixtures with improved elastic restorations, for example of 50%, are obtained with good cold-melt flexibility. {Polymer-modified bitumen; elastic return; Polymer components; mixtures; Kaelteflexibilitaet}

Description

Polymer modified bitumen with improved elastic recovery

Field of application of the invention

The invention relates to polyalkyl (meth) acrylate-based polymers as bitumen improvers and to those modified bitumens having improved technical properties.

Characteristic of the known state of the art

Bitumen, which is a mixture of substantially different hydrocarbons, with varying proportions of paraffinic, naphthenic and aromatic hydrocarbons, is widely used for its properties, for example for the production of road surfaces, as potting compounds, in building protection as paints or in the form of Roofing boards and as Abdicutungsmittel against groundwater.

Due to the specific Proauktionseigenschaften - bitumens have depending on the crude oil provenance, little to no elastic properties - brittle coverings produced therewith at low temperatures and soften at higher temperatures.

By adding various additives, in particular polymers, it is attempted to achieve a compensation of the bitumens, in particular an improvement in the theological properties, e.g. the asphalt, a bitumen-mineral mixture, primarily for road construction, "should provide sufficient stability and cold flexibility as well as a high fatigue strength with constantly increasing traffic loads." Thus, the addition of polymer can increase the so-called plasticity margin, ie the difference between softening point and breaking point.

-2-

A reduction in the breaking point (DIN 52 012) and an increase in ductility (DIN 52 013) by polymer addition indicate better cold flexibility. The purpose of the polymers as bitumen additives is to change the elastoviscous behavior of bitumen, that is, to extend its plasticity margin and to improve elastic recovery.

In addition to natural and synthetic rubbers, polymers, thermosetting resins and thermoplastics have been tested as bitumen improvers (Körner et al., Plate and Kautschuk 24 (1977, 475 to 478).) As polymer bitumen additives are currently mainly styrene / butadiene (SB) -, EPDM - And ethylene / vinyl acetate (EVA) copolymers "and especially for industrial bitumen, also used atactic polypropylene technically.

Commercially available polymer modified bitumens are i.a. Caribit (SB.Shell), Olexobit (EPDM, BP), Styrelf (SB, Eleven).

Polymers based on acrylate and methacrylic acid, in particular polymers of alkyl methacrylic acid esters (PAMA), are also described as bitumen improvers. A broader technical use of these polymers, despite good

Fulfillment of a number of requests made as additives, especially because of insufficient improvement in the elastic recovery of ready-to-use elastomer-modified bitumens, not yet found.

US Pat. No. 2,202,082 describes bituminous mixtures of bitumen and 2 to 5% poly-C 1 -C 10 -alkyl methacrylates, without specifying their molecular weights, thereby improving the ductility of the bitumen.

US Pat. No. 2,848,429 also describes bituminous mixtures with improved ductility obtained by addition of 0.01 to 0.5% rubber and poly-C 3 -C 24 -alkyl (meth) acrylates. The PAMA ¹ S have molecular weights of 5,000 to 500,000.

The German patents DE-AS 12 40 773 and DE-OS

No. 2,331,727 likewise describe improved bituminous road surface binders with polymers of alkyl methacrylates, without giving any more specific details about these polymers.

Further, polyalkyl (meth) acrylates or copolymers of alkyl (meth) acrylates are proposed as Bitumenverbesserungsmittel, in DE-OS 25 09 473 a solid copolymer having molecular weights of 50,000 to 500,000, which consists of alkyl (meth) acrylates with Alkyl groups containing more than 6 carbon atoms, as well as from

From 3 to 20% by weight of acrylic acid or methacrylic acid and from up to 20% by weight of basic nitrogen-containing monomers, in Japanese Patent Laid-Open Publication No. 52-141,829, stepwise emulsion-polymerized additives and in WO 88/07 067 Poly -C ₄ -C ₂ o-alkyl methacrylates with

-4- / QO} jq

Molecular weights of about 5,000 to about 1,000,000, and which are contained in amounts of from 0.01 to about 10 wt .-% in the modified bitumen.

Prerequisites for the polymeric additives for the use of property improvements in biturr.jnösen Genmischen are oxidation and thermal stability of the polymers, their ease of incorporation in bitumen, compatibility with different bitumen and the stability of the bitumen-polymer mixture.

The known polymeric bitumen additives sufficiently enhance the low-temperature flexibility in bituminous mixtures and mineral mixes made therewith, i. Breaking point and ductility of such materials are favorably influenced by the known polymer additives.

High fatigue strength and elasticity of the asphalts produced with bituminous binders, which are determined by the elastic properties of the bitumens, are present, for example, in practice, in some cases strongly deformed asphalt street corners, in not yet sufficient or good measures.

Object of the invention

Dyrch the invention eliminates the disadvantages of the known art.

Explanation of the essence of the invention

The object of the invention is to find polymers which, when used in bituminous mixtures, have the elastic properties, measured e.g. as elastic recovery, of bitumen preparations significantly improve, and further the known and required conditions

no

such as high thermal stability and Oxidat.ionsbeständigkeit, as well as good low-temperature flexibility and have good incorporability and compatibility,

It has been found that polyalkyl (meth) acrylates of certain compositions are effective bitumen additives which improve both low-temperature flexibility and, to a very great extent, the elastic properties of bitumen and thus of bituminous compositions. Surprisingly, it has been found that in polymer-modified bitumen, by Folyalkyl (meth) acrylates long-chain alkyl esters, by copolymerization with polymerizable carboxylic acids and / or polymerizable basic nitrogen compounds, and both incorporated in amounts of less than 3 wt .-% in the copolymer or in a Copolymer mixtures are present, and welchn molecular weights Mw übp.r have 30 000, high elasticity can be achieved.

The invention therefore relates

Polymer-modified bitumen with improved elastic recovery, containing from 0.5 to 20% by weight of polymer constituents, these polymer constituents being at least 20% by weight of polyalkyl (meth) acrylates having molecular weights above 30 000,

characterized,

that the polyalkyl (meth) acrylate in proportions of 50 to 99.8 wt .-% of Cg to C26 ~ alkyl (meth) acrylates, in proportions of 0.1 to 2.8 wt .-% of polymerizable carboxylic acids, in Levels of 0.1 to 2.8 wt .-%

HO

polymerizable basic nitrogen compounds and in proportions of 0 to 49.8 wt .-% of one or more other polymerizable compounds having not more than one polymerizable double bond is constructed.

The polyalkyl (meth) acrylate of the specified composition to be used according to the invention may be a copolymer of the stated comonomers or a mixture of copolymers of alkyl (meth) acrylates with polymerisable carboxylic acids and / or polymerisable basic nitrogen compounds. The alkyl (meth) acrylate copolymers and / or mixtures of copolymers with compositions of the invention may be used both as a solution, e.g. be added in a suitable mineral oil, as an aqueous emulsion or in pure form the bitumen or bituminous mixtures.

Although it is known from the prior art, by addition of polyalkyl (meth) acrylates _; which have molecular weights in the range of about 50,000 to about 1,000,000, improve in polymer-modified bitumens the cold flexibility, which is expressed in the characteristics of breaking point and ductility, but insufficiently the elastic recovery, which is permanent Deformations must be accepted, for example, in road surfaces, which in turn contain high road safety risks.

For example, the specification of the technical delivery conditions for ready-to-use polymer-modified

Bitumen, Tl PmB 88, part 1, version of 30.12.1988, for various PmB grades Elastic recovery requirements of at least 50%.

To prove the elastic properties of ready-to-use elastomer-modified bitumen, the test of the elastic recovery according to the half-thread method in the ductilometer is carried out as follows in accordance with DIN 52013 at 25 ° C.

Notwithstanding DIN 52013, the specimens are pulled out only up to a Fadenlä'ige 20 cm and the thread after locking the feed within 10 s with a pair of scissors in the middle of the thread into two half-threads. The elastic recovery is defined as the distance that occurs after 30 minutes between the two ends of the semi-filament. It is stated in%, based on the initial strain.

The examples with the comparative examples demonstrate the low elastic recovery when using pure polyalkyl (meth) acrylates having molecular weights Mw under / 1,000,000 and the considerably higher values in the PmBs according to the invention. (Compilation see Table 1)

The construction of the copolymer additives according to the invention with (meth) acrylic acid esters ensures good thermal stability, good oxidation resistance and good solubility, ie. also easy incorporation into almost all types of bitumen.

WHO

Implementation of the invention

For the preparation of the (meth) acrylic acid alkyl ester copolymers to be used according to the invention, long-chain alkyl esters of acrylic acid and / or above all of methacrylic acid with Cg- to C26- ί in particular with Cq to C20 ~ alkyl ^radicals / advantageously with C ^ q- to C ^ s " Examples of such esters are n-octyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, n-decyl methacrylate, isodecyl acrylate, isodecyl methacrylate, dodecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, eicosyl methacrylate, tricosyl methacrylate, the long chain ones used for the ester production alcohols are preferably used as synthetic alcohols and which usually mixtures of different alcohols in the Ce ^- display up C2g area such alcohols are known commercially, for example under the brand names © Lorol®, © Alfol, © Dobanol, ® behenyl SR One, for example,.. the preparation of isodecyl methacrylate useful tec Hnischer alcohol is a mixture of isomeric isodecyl alcohols with an average C number (C) = 9.9 -10.3.

The bitumen-modified polyalkyl (meth) acrylates are from 50 to 99.8 wt .-%, especially from 60 to 99.5 wt .-% and in particular from 80 to 99 wt .-% of long-chain Cg- to C26 ~ Alkyl esters of acrylic acid and / or especially of methacrylic acid, which are advantageous mixtures of different C3 to C26 ~ alkyl esters.

The acidic and the basic comonomers are in amounts of less than 3 wt .-%, which are 0.1 to 2.8 wt .-%, especially 0.2 to 2.5 wt .-%, in particular 0.5 to 2.0 wt .-% of each of these functional monomer, incorporated in the copolymer or the copolymers to be mixed. As acid monomers, acrylic acid and methacrylic acid are preferable. But also, for example, maleic acid or its anhydride, and crotonic acid or itaconic acid may be incorporated as an acid Comonomsre exclusively or together with acrylic acid and / or methacrylic acid.

Basic monomeric compounds include those with secondary or tertiary amino or amido groups or with basic heterocyclic groups. Unsaturated compounds with primary amino groups generally prevent radical polymerization and are then unsuitable. In contrast, unsaturated compounds having secondary amino groups, e.g. tert-butyl aminoalkyl ester of acrylic or methacrylic acid, polymerizable when the hydrogen atom of the amino group is sterically shielded. Preferred monomers having a basic nitrogen atom are the dialkylaminoalkyl esters or the dialkylaminoalkylamides of acrylic or methacrylic acid, in particular those having a total of 7 carbon atoms and N-alkylacrylamides or -methacrylamides. Examples are dimethylaminoethyl acrylate or methacrylate, dimethylaminopropyl acrylate or methacrylate,

Dimethylaminobutyl acrylate or methacrylate, N-methylacrylamide, N-methylmethacrylamide, dimethylaminoethylacrylamide or -methacrylamide and those called esters or amides which, instead of a dimethylamino group, are a diethylamino, dipropylamino, dibutylamino, methylethylamino, methylbutylamino, morpholino or piperidino group contain. Suitable basic monomers further include vinylpyrrolidone, vinylpyridine, vinylimidazole, vinylimidazoline, vinylpyrazolone, vinylpiperidine, and the acrylic or methacrylic acid esters of imidazolylalkanols or imidazolinylalkanols.

In proportions of from 0 to 49.8% by weight, especially in proportions of from 0 to 20% by weight, the copolymers can be composed of one or more other copolymerizable compounds having a double bond. Examples of monomers which are not essential for the preparation of the copolymer of the invention include, by way of example, acrylic and / or methacrylic esters of C 1 - to C 7 -alcohols , such as methyl methacrylate, isobutyl methacrylate, n-butyl acrylate, isoamyl methacrylate, n-hexyl acrylate, further acrylonitrile, acrylamide, methacrylamide, Styrene, vinyl acetate.

To incorporate the elastic recovery enhancing polymers into the bitumens, they are loaded as a solution, especially those in a suitable mineral oil, e.g. a more viscous naphthenic lubricating oil, as an aqueous emulsion or in

pure form the bitumen enforce. The preparation of the polyalkyl (meth) acrylates can therefore be carried out by the conventional processes by predominantly radical polymerization of the monomers in solution or in emulsion, but also in bulk (cf., H. Rauch-Puntigam, Th.Völker, acrylic and methacrylic compounds, Springer-Verlag, Berlin, 1967, in particular pages 203, 207, 230 233, 238, 327). The molecular weight setting, which should be more than 3 times 10 ⁴ , in particular> 5 times 10 ⁴ , for the polyalkyl (meth) acrylates to be used according to the invention, is determined above all by the amount of the initiator initiating the polymerization in relation to the polymerizable monomers or the concomitant use of a Regulator, for example, an alkylmercaptan determined and is carried out by known methods. The molecular weights Mw in g / mol of the polymers obtained are determined by the light scattering method (Ullmanns Encyklopadie der Techn. Chemie, 4th edition, volume 15, pages 385 to 387) or the calibration relationship given below and the viscosities according to DIN 7745 with Chloroform measured as solvent at 20 degrees C.

The bitumens are added for the modification according to the invention polyalkyl (meth) acrylates having acidic and basic groups in the molecule and with molecular weights of> 3 times 10 ⁴ in amounts of 1 to 10 and in particular in amounts of 2 to 8 wt .-%. In addition to the polyalkyl (meth) acrylates according to the invention, the polymer-modified bitumens according to the invention, other than finishing components for bituminous binders and

12 1.91 MO

Mixtures, known polymeric compounds, such as polyolefins (polyethylene, polypropylene) ethylene-vinyl acetate copolymers or acrylonitrile-butadiene-styrene copolymers.

For the purposes of the present invention, bitumen is any of which is e.g. understood in road construction or roofing construction as Verguß-, sealant or paint masses commonly used bitumen.

EXAMPLES

The indicated molecular weights were obtained from the T) sp / ^C "values by the following calibration:

(Chloroform, 20 ° C) = 0.0156 Mw ^{0 '645}

example 1

In a 15 l steel kettle with stirring, reflux condenser, internal thermometer and ölurilaufheizung 4 900 g of isodecyl methacrylate, 50 g of methacrylic acid and 50 g of dimethylaminoethyl were submitted and heated to 150 degrees C. By addition of 150 g CC> 2 ice was degassed and the polymerization started by adding 6 g of t-butyl perbenzoate. 3 hours after addition of the initiator was diluted with 2 500 g of a naphthenic lubricating oil viscosity 8.5 mm ² / s at 100 degrees C. Subsequently, the kettle temperature was raised to 100 ° C and another 6 g of t-butyl perbenzoate were added. After another 10 hours, it was again diluted with 2,500 g of lubricating oil to a concentration of 50%.

Ti _S p / c (chloroform, 20 degrees C) = 97 ml / g Mw = 760,000 g / mol (according to calibration relationship) conversion = 98.6%

80 g of the polymer solution was added at 150 ° C. to .1 000 g of B 200 bitumen. After 1 hour of stirring in

Round bottom flask with saber at 150 degrees C, the polymer was completely dissolved. The polymer-modified bitumen obtained was homogeneous.

Example 2

In a 4 1 flask with stirring, internal thermometer and reflux condenser, 600 g of n-octane, 588 g of isodecyl methacrylate, 6 g of methacrylic acid and 6 g of dimethylaminoethyl were submitted and heated to 85 ° C by means of an oil bath. After passing N2 for 1 hour, 1.2 g of t-butyl peroctoate was added. After 3 hours, another 1.2 g of t-butyl peroctoate was added. After a total of 10 hours, the polymerization was complete. The polymer was then precipitated by pouring the octane solution in ethanol and dried.

7 | _S p / c (chloroform, 20 degrees C) = 68 ml / g Mw = 439,000 g / mol (according to calibration relationship) conversion = 99.5%

40 g of the isolated and dried polymer were added at 150 ° C. to 1000 g of B 80 bitumen. After 1 hour of stirring in a round bottom flask with saber at 150 degrees C, the polymer was completely dissolved. The polymer-modified bitumen obtained was homogeneous.

Example 3

In a stirred 4-liter flask, internal thermometer and reflux condenser, 180 g of a naphthenic lubricating oil (viscosity at 100 degrees C = 8.5 mm ² / s), 999.6 g of isodecyl methacrylate, 10.2 g of methacrylic acid and 10.2 g 3-dimethylamino-2,2-dimethylpropyl-l-methacrylate presented and heated to 75 degrees C.

By discharging N2 for one hour was degassed. Subsequently, 0.61 g of t-butyl perpivalate and 0.61 g of t-butyl perbenzoate were added. After 4 hours, 840 g of naphthenic base oil was diluted and another 1.5 hours later 2 g of t-butyl perbenzoate was again added. After a total of 11 hours, the polymerization was complete.

T | sp / ^C (chloroform, 20 degrees C) = 97

Mw = 760,000 g / mol (according to calibration relationship)

Sales = 97%

80 g of the polymer solution were added at 150 ° C in 1 000 g of bitumen type B 200 and completely dissolved within one hour. The polymer-modified bitumen obtained was homogeneous.

Comparative Example 1

Preparation of a polyisodecyl methacrylate

160 g of n-decyl methacrylate and 40 g of n-octane were dissolved in a 500 ml four-necked flask with internal thermometer, saber stirrer

ie

and reflux condenser and heated to 85 degrees C by means of an oil bath. After reaching this temperature, degassing by introduction of N2, then 0.32 g of t-butyl peroctoate were added

After 2 hours, it was diluted with 28.6 g of n-octane and after a further hour 0.32 g of t-butyl peroctoate were added. After 16 hours Gesamtpolymerisationsdauer the polymethacrylate was isolated by pouring into ethanol and then dried.

* | sp / c = 90 ml / g Mw (light scattering) = 710,000 g / mol

By dissolving 40 g of the polymer in 960 g of B 200, a homogeneous polymer-modified bitumen was obtained as described in Example 1.

Comparative Example 2

Preparation of a Polyisodecylmethacrylates

In a 500 ml four-necked flask, 15 g of naphthenbasiches lubricating oil (viscosity at 100 degrees C = 11.5 mm ² / s) and 85 g of isodecyl methacrylate were introduced and heated to 82 degrees C. N2 was then introduced for 1/2 hour, and 0.17 g of t-butyl-peroctoate was added. A mixture of 45 g of naphthenic base oil, 255 g of isodecyl methacrylate and 0.5 g of t-butyl peroctoate was added within 3 hours by means of a metering pump

added. 20 minutes after the end of the feed was diluted with 280 g naphthenbasischem oil, after another 100 minutes, again 0.5 g of t-butyl peroctoate was added. After 16 hours, the polymerization was complete. The viscosity of the solution was 4,560 mPa s at 150 degrees C.

Ti _S p / c (chloroform, 20 degrees C) = 88 ml / g Mw (light scattering) = 695,000 g / mol

80 g of the solution of the polymethacrylate were dissolved by stirring for one hour at 150 ° C. in 1000 g of bitumen B 200.

Comparative Example 3

Preparation of a Polyisodecylmethacrylates

As in Example 1, 222 g of isodecyl methacrylate, 3 g of methyl methacrylate and 275 g of n-octane were initially charged, heated to 85 ° C. and degassed by addition of CO 2 ice. Then 0.45 g of t-butyl peroctoate was added. After 3 hours, 0.45 g of t-butyl peroctoate was again added. The total polymerization time was 16 hours. By pouring into ethanol, the polymer was isolated and then dried.

"Hsp / ⁰ (chloroform, 20 degrees C) = 55 ml / g Mw (light scattering) = 340,000 g / mol

60 g of the isolated polymethacrylate were dissolved by stirring at 150 ° C. in 1 000 g of bitumen B for one hour.

The following table shows the measured data obtained on the polymers and PMBs prepared according to Examples 1 to 3 and Comparative Examples 1 to 3 and on the underlying bitumen types.

TABLE 1

PMB- ^ sp / C EP Pene breaking point

b w?. Mer B-type of the poly-C ^{0 0} C 0.1 mm

Ductility (cm) 25 ⁰ C 13 ⁰ C 7 ⁰ C

Elastical reset

Example 1 Example 2 Example 3

97 68 98

40 52 40

231

79

197

-26 -19 -27

> 100> 100

> 100

> 100

67 1 52? Ό 70 %

"D

Comparative Example 1

Comparative Example 2

Comparative Example 3

90

88

55

43 132

47 105

51 74

-29

-27

-17> 100

> 100

> 100

25 y

34? O

J.1 / ο

,1)

39 49

190 88

-18 -16

> 100

> 100

0 s

1 p

EP = softening point, ring and ball, DIN 52011 Pene = needle penetration, DIN 52010 Breaking point according to Fraas, DIN 52010 ductility, DIN 52013

Elastic default: 1) Modif. DIN 52013

2) Torsionsrückverformung method after Esser, road and civil engineering, Issue 4, 1962, p 342 and Thompson, Hagman, Proc. AAPT 27 (1958) p. 494

Claims (7)

A polymer-modified bitumen having improved elastic recovery by a content of 0.5 to 20% by weight of polymer constituents, these polymer constituents being at least 20% by weight of polyalkyl (meth) acrylates having molecular weights above 30 000, characterized, in that the polyalkyl (meth) acrylate is used in proportions of from 50 to 99.8% by weight of C ₈ - to C 26 -alkyl (meth) acrylates, in proportions of from 0.1 to 2.8% by weight of polymerisable carboxylic acids, in proportions of from 0.1 to 2.8% by weight of polymerisable basic nitrogen compounds and in proportions of from 0 to 49.8% by weight of one or more other ρ_ymerisable compounds having not more than one polymerizable double bond. 2. Polymer-modified bitumen according to claim 1, characterized in that the polyalkyl (meth) acrylate in proportions of 50 to 99.8 wt .-% of C ₈ - to C ₈ alkyl (meth) acrylates is constructed. 3. polymer modified bitumen according to claims 1 and 2, characterized in that the polyalkyl (meth) acrylate in proportions of 0.2 to 2.5, preferably 0.5 to 2.0 wt .-% polymerizable Carboxylic acids and with proportions of 0.2 to 2.5,
preferably 0.5 to 2.0 wt .-% polymerizable
basic nitrogen compounds is constructed. 4. polymer modified bitumen according to claims 1 to 3, characterized in that the polymer additive
exclusively of alkyl (meth) acrylate copolymers
consists. 5. polymer modified bitumen according to claims 1 to 4, characterized in that the
Polyalkyl (meth) acrylate is a copolymer Alkyl (meth) acrylates, polymerizable carboxylic acids
and polymerizable basic nitrogen compounds. 6. Polymer modified bitumen according to claims 1 to 4, characterized in that the Polyalkyl (meth) acrylate a mixture of copolymers of alkyl (meth) acrylates and polymerizable
Carboxylic acids and / or polymerisable basic
Is nitrogen. 7. polymer modified bitumen according to claims 1 to 6, characterized in that the elastic
Provision at least 50% points over
unmodified bitumen is raised.