RU2405796C1 - Adhesive additive for bitumen and bitumen-polymer compositions - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: adhesive additive based on maleinised low molecular weight polybutadiene contains bound maleic anhydride in amount of 21.5-33 wt %, alkenyl succinic anhydride as described in claim 1, with weight ratio of maleinized low molecular weight polybutadiene: alkenyl succinic anhydride equal to 25-85:75-15. The range of batching said adhesive additive per bitumen composition equals 0.4-0.8 wt %. When using the additive, there is no need for pre-mixing the adhesive additive with thermoplastic. Owing to this, the bitumen composition is prepared in a single step. The polymer-bitumen composition with an additive is characterised by high level of adhesion of mineral filler to alkaline and acidic mineral filler.

EFFECT: adhesive additive is characterised by dynamic viscosity of 0,2-1,0 Pa·s, can be easily batched and has good distribution in the bitumen composition.

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Description

The invention relates to adhesive additives for bitumen-polymer compositions.

Adhesive additives provide the connection of bitumen with mineral filler during the construction of roads, the arrangement of roofing. They significantly increase the adhesion properties of bitumen - improve the adhesion of bitumen to mineral materials. In this case, the physical and mechanical properties of bitumen do not deteriorate.

A number of adhesive additives are known for bitumen-polymer compositions based on nitrogen-containing compounds: quaternary ammonium bases - cationic surfactants, piperazine derivatives, imidazolinol (Sat. "Use of surfactants in road construction." CIVSSM, Astrakhan, 2001) . Dosage of nitrogen-containing additives from 0.5 to 2.0% per bitumen composition. They retain their properties to a temperature of 160-163 ° C. Significant disadvantages of these additives are unpleasant (amine) odor and high toxicity (these are, as a rule, substances of the 2nd hazard class according to GOST 12.1.007-76).

An adhesive additive is also known, which is the product of the interaction of taly oil and triethanolamine with a mass ratio of 66-68: 32-34, respectively (RU No. 2119513, C08L 95/00, 09/27/1998). It is used in dosages of 0.7-7.0%. The additive has the following disadvantages:

- due to the high viscosity of the additive, a stage of preheating it before introducing it into the bitumen composition is necessary;

- the variable composition of melt oil, depending on the source of natural raw materials (deciduous or coniferous trees) significantly affects the adhesive properties of the additive,

- bad smell

- high dosages to ensure the right level of adhesion.

Closest to the claimed technical solution is an adhesive additive to the bitumen composition, which is maleinized low molecular weight polybutadiene with a content of bound maleic anhydride of 12-21 wt.%, Having a dynamic viscosity at 25 ° C of 10-100 Pa · s (RU No. 2226203, IPC C08L 95/00, 53/02, 15/00, 03/27/2004).

The disadvantage of this adhesive additive is its high viscosity: 10-100 Pa · s at 25 ° C. Because of this, technological difficulties arise in introducing an additive into bitumen compositions.

The task of the invention is to improve the technological properties of the additive while maintaining the adhesive properties of the bitumen compositions in which it is used at the same level as in the case of using known adhesive additives.

The technical result consists in reducing the viscosity of the adhesive additive, while maintaining the indicator "adhesion with mineral carriers" of polymer - bitumen compositions in which it is used at the same level as in the case of the use of known adhesive additives.

The technical result is achieved by the fact that the known adhesive additive based on maleinized low molecular weight polybutadiene containing bound maleic anhydride according to the invention further comprises an alkenyl succinic anhydride of the general formula:

where n = 12-26

with a mass ratio of maleized low molecular weight polybutadiene: alkenyl succinic anhydride 25-85: 75-15, and the content of bound maleic anhydride in it is 21.5-33 wt.%.

The table shows the characteristics of the inventive adhesive additives and the test results of the polymer-bitumen compositions containing it.

The inventive adhesive additive is characterized by high technological properties - the value of dynamic viscosity is significantly lower than for known adhesive additives - 0.2-1.0 Pa · s. It is easily dosed and well distributed in the bitumen composition. When using it, the operation of preliminary mixing of the adhesive additive with thermoplastic elastomer is not required. Due to this, the preparation of the bitumen composition is carried out in one stage.

A polymer - a bitumen composition containing it, is characterized by the same high level of adhesion with mineral fillers to both alkaline and acidic mineral fillers, as in the case of using known adhesive additives. The optimal dosage range of the inventive adhesive additives in the composition of the bitumen composition of 0.4-0.8 wt.%, Per composition.

The inventive adhesive additive can be obtained in two ways:

1. By mixing, when heated, separately obtained maleinized low molecular weight polybutadiene and alkenyl succinic anhydride in a given ratio of components.

2. The implementation of the maleinization process in one reactor in two stages: at the first stage, the α-olefin maleinization of the formula C _n H _{2n is maleinized} , where n = 12-26 with an excess of maleic anhydride; at the second stage, the calculated amount of low molecular weight polybutadiene is fed into the reactor and the maleinization process is continued.

In carrying out the invention, the following products are used:

Low molecular weight polybutadiene - according to TU 38.103641-98 α - Olefins - according to TU 2411 - 058 - 05766801-96 Maleized   low molecular weight   polybutadiene - according to TU 0257-12-33452160-2003 Oil bitumen - according to GOST 22245-90 Maleic Anhydride - according to GOST 11153-75

Alkenyl succinic anhydrides were obtained from industrial fractions of α-olefins produced by Nizhnekamskneftekhim.

The determination of dynamic viscosity is carried out on a Hepler rheo-viscometer (Reotest 2.1).

The content of free (unreacted) maleic anhydride is determined by titration with an alkaline solution of an aqueous extract from an additive.

The content of total maleic anhydride is calculated by the acid number found by non-aqueous alkali titration of an adhesive additive.

The content of bound maleic anhydride is calculated from the difference between the amount of total and free maleic anhydride.

The number average molecular weight (Mn) of low molecular weight polybutadiene is determined by gel permeation chromatography.

The polydispersity of the used samples of low molecular weight polybutadiene is 1.9-2.6.

The invention is illustrated by examples of specific performance.

Example 1

97.5 kg of BND 60/90 grade oil bitumen heated to 140-160 ° C are loaded into a tank equipped with a paddle mixer and a circulation pump, 2 kg of DST - 30-01 thermoplastic elastomer are fed in the form of crumbs and 0.5 kg of adhesive additive , which is a mixture of low molecular weight maleated polybutadiene with alkenyl succinic anhydride (n = 16) in a mass ratio of 60:40. The adhesive additive has the following characteristics: dynamic viscosity - 0.75 Pa · s, acid value - 131.0 mg KOH / 1 g, the content of total maleic anhydride - 22.22%, free maleic anhydride - 0.22%, the content of bound maleic anhydride - 22.0%. Mixing is carried out at a temperature of 150-160 ° C for 60 minutes until the thermoelastoplast is completely dissolved. Adhesive additive completely dissolves within 5 minutes.

A sample of the bitumen composition is tested by standard methods.

Examples 2-9

All operations are carried out as in example 1. Change the composition of the adhesive additive, its characteristics and its dosage in the composition of the bitumen composition. Data on the composition, characteristics of adhesive additives and properties of bitumen compositions are given in table 1.

Example 10 (prototype)

A linear elastomeric thermoplastic elastomer, DST-30-01, is loaded into a rubber mixer in the form of crumbs in an amount of 2 kg and low molecular weight maleated polybutadiene in an amount of 0.5 kg, containing 12 wt.% Bound maleic anhydride having a dynamic viscosity of 10 Pa · s. Polymers are mixed for 15-20 minutes at normal temperature. The resulting mixture in the form of loose crumb in the amount of 2.5 kg is fed into a container equipped with a paddle mixer and a circulation pump, in oil bitumen, heated to 140-160 ° C and mixing is carried out at a temperature of 150-160 ° C for 60 minutes until complete polymer dissolution.

A sample of the bitumen composition is subjected to standard tests.

The test results are shown in table 1.

Thus, tests have shown that the adhesion additives synthesized according to the invention provide bitumen and bitumen-polymer compositions with a high level of performance, including high adhesion of the compositions to mineral fillers.

Claims (1)

Adhesive additive for bituminous and bitumen-polymer compositions based on maleinized low molecular weight polybutadiene containing coupled maleic anhydride, characterized in that it additionally contains alkenyl succinic anhydride, where alkenyl contains 12-26 carbon atoms (n = 12-26) or it is obtained from the fraction (i) α-olefins with the number of carbon atoms 12-26, with a weight ratio of maleized low molecular weight polybutadiene: alkenyl succinic anhydride 25-85: 75-15, with a content of bound maleic anhydride in it of 21.5-33 wt.% and up to irovke adhesive additive of 0.4-0.8 wt.% on the bitumen composition.