RU2241897C2 - Insulating bitumen-polymer mastic and a method for preparation thereof - Google Patents

Abstract

FIELD: cementation substances.

SUBSTANCE: mastic intended for anticorrosive protective coatings of underground pipelines contains, wt %: bitumen mix (BND-50.90 - 85-90 and BNI-4 - 1-20 or BN-70/30 - 1.90; divinylstyrene thermoelastoplastic 1.5-5; plasticizer 1-5; filler 1-8; petroleum-polymer resin 2-8; adhesive additive 0.3-1.5; and modifier 1-6. Preparation procedure comprises preparing first mix from road and insulation or construction bitumens, heating the mix to 160-179^оС in order to dehydrate it, loading it into mixer, adding plasticizer, stirring resulting blend for 2.5-3.5 h at 165-175^оС until plasticizer completely dissolves, after which filler, e.g. rubber crumb, is added and the total is agitated for 25-35 min before addition of petroleum-polymer resin, modifier, adhesive additive, and thermoelastoplastic.

EFFECT: increased reliability of coating.

1 tbl, 2 ex

Description

The invention relates to materials used for insulation of pipes and pipe systems, and can be used in the construction and repair of pipelines for various purposes, including underground oil pipelines, oil pipelines and gas pipelines in summer and winter.

Known mastics for corrosion protection containing bitumen, cement, sand and granular material (see US patent 4196922, IPC F 16 L 58/12, 04/08/1980).

From the same patent, a method for making mastic is known, which consists in mixing bitumen and filler.

This mastic and its manufacturing method make it possible to obtain mastic, which can be used only in the summer period or in conditions where there is no temperature drop below 0 ° C, in particular for protecting underwater pipelines. Thus, the scope of this kind of mastic is limited.

Closest to the invention in technical essence and the achieved result is bitumen-polymer mastic for corrosion protection, which contains bitumen, thermoplastic elastomer and filler (see, application UK 1538267, IPC F 16 L 58 / 12.17.01.1979) .

From the same application of Great Britain 1538267, a method for manufacturing a mastic is known, comprising mixing the components that make up the mastic.

However, this mastic has insufficient adhesion to steel - the material from which various kinds of pipelines are most often made. In addition, this mastic does not provide the required reliability of the protection of the pipeline from corrosion in conditions of significant temperature drops, as well as at negative ambient temperatures. As for the method of making mastic, it is quite laborious.

The problem to which the present invention is directed, is to improve the quality of corrosion protection of underground pipelines and increase the trouble-free service life of underground oil and gas pipelines.

This problem is solved due to the fact that, as part of the device as an object of the invention, the insulating bitumen-polymer mastic for anti-corrosion protective coatings of underground pipelines includes a mixture of bitumen, thermoplastic elastomer, plasticizer and filler, while a mixture of bitumen BND-60/90 and BNI is used as bitumen -4 or BN -70/30, divinyl styrene thermoplastic elastomer was used as a thermoplastic elastomer, and a modifier, an oil-polymer resin and an adhesive additive were added to the mastic, while the mastic and has the following composition of components, wt.%: bitumen BND-60/90 8.5-90, bitumen BNI-4 1-20 or bitumen BN-70/30 1-90, divinyl styrene thermoplastic elastomer 1.5-5, plasticizer 1 -5, filler 1-8, petroleum resin 2-8, adhesive additive 0.3 - 1.5 and modifier 1-6.

In terms of the method as an object of the invention, this problem is solved due to the fact that the method of manufacturing bitumen-polymer mastic involves mixing bitumen, thermoplastic elastomer, plasticizer and filler, while mixing the components of the mastic as follows: first prepare a mixture of road and insulating bitumen or building bitumen then this mixture is dehydrated by heating to a temperature of 160-170 ° C, a mixture of bitumen is fed into the mixer and added to the last plasticizer, the resulting mixture is mixed At a temperature of 165-175 ° C for 2.5-3.5 hours until the plasticizer is completely dissolved, then a filler, for example rubber crumb, is added, and the resulting mixture is stirred for 25-35 minutes, then stirring is continued and an oil-polymer resin, modifier is added, adhesive additive and thermoplastic elastomer.

As the studies showed, the proposed insulating bitumen-polymer mastic favorably differs from the traditionally used for forming bitumen mastic coatings by increased adhesion to steel and polymer materials in the temperature range from plus 40 ° C to minus 20 ° C and retains the ability to withstand mechanical shear, impact and other effects (deformation) at negative temperatures (up to minus 20 ° С).

The use of the proposed insulating mastic reduces the likelihood of accidents at oil pipelines, which entail a deterioration of the environmental situation in the area of their laying.

Viscous bitumen BND-60/90 in accordance with GOST 22245-90, construction bitumen BN-70/30 in accordance with GOST 6617-76, insulating bitumen BNI-4 in accordance with GOST 9812-74 are used as bitumen.

As divinylstyrene thermoplastic elastomer use DST 30R-01 group 1 according to TU 38.40327-98, Izm. No. 1.

As a modifier, rubber PBN TU 38103641-98.

As a filler, crushed rubber crumb RD-05 according to TU 38-108-03597 is used, and the plasticizer is industrial oil I-40A according to GOST 20799-88.

As a strength additive, a petroleum-polymer paint and varnish resin is used according to TU 38.10916-79.

A surfactant based on low molecular weight maleated polybutadiene is used as an adhesive additive.

During the study, a coating based on insulating bitumen-polymer mastic was applied mechanically or manually by pouring with molten mastic pre-cleaned and coated with a bitumen primer (BNI-4 bitumen solution in gasoline in a ratio of 1: 2 by weight) of the pipe surface (pipeline). To achieve the required thickness, the mastic layer was reinforced with either fiberglass or non-woven polymer fabric. Over the reinforced mastic layer, a wrapping layer of polymer tape, for example, polyvinyl chloride (PVC) or polyethylene (PE), was applied in a spiral.

To increase the adhesion force of the mastic components to each other, an oil-polymer resin is added to the mastic. The addition of resin allows to increase the strength characteristics of the mastic (resistance to impact, shear and indentation).

As can be seen from the table, the coating of the proposed bitumen-polymer mastic has a higher adhesion to steel and to polymer adhesive tapes. In addition, the coating obtained by applying the inventive bitumen-polymer mastic on a steel pipe according to the bitumen primer has a higher strength compared to the known insulating bitumen-polymer mastic, while the strength of the coating upon impact at a temperature of minus 15 ° C is 2.0 J.

As studies have shown, the use of the proposed mastic allows to achieve adhesion to steel more than 0.6 MPa at 20 ° C and maintain it at temperatures up to minus 15 ° C at a level not lower than 0.2 MPa. Due to the fact that the insulating bitumen-polymer mastic maintains adhesion and ductility at low ambient temperatures, the coating formed from it has high mechanical strength, does not crack and does not crack when laying the pipeline in the ground in winter.

The proposed insulating mastic is prepared as follows.

In a certain proportion indicated above, a mixture is prepared from road and insulating or building bitumen and this mixture is dehydrated by heating to a temperature of 160-170 ° C.

A mixture of bitumen is fed into a mixer into which a plasticizer is added, and all this is mixed at a temperature of 165-175 ° C, preferably 170 ° C, for 2.5-3.5 hours, preferably 3 hours, until the plasticizer is completely dissolved.

In the next step, a filler, rubber crumb, is added to the stirred mixture, and mixing continues for about 0.5 hours.

At the last stage, the remaining components are added to the mixed mixture, i.e. petroleum polymer resin, modifier - liquid rubber, adhesive additive - low molecular weight polybutadiene maleized and thermoelastoplast - divinyl styrene thermoelastoplast.

The total cooking time is 4.5 - 5 hours.

In the course of the research, a number of compositions were obtained with the most optimal component ratios in the proposed mastic, from which coatings were formed on the pipes. The content of the components in the examples is indicated in wt.%.

Example 1. Bitumen BND 60/90 72%, bitumen BNI-4 10%, divinyl styrene thermoplastic elastomer 4.0%, plasticizer 2.0%, filler 6.0%, petroleum resin 2.0%, adhesive additive 1.0% modifier 3.0%.

Example 2. Bitumen BND 60/90 10%, bitumen BN 70/30 78.5%, divinyl styrene thermoplastic elastomer 2.5%, plasticizer 2.0%, filler 1%, petroleum resin 3.0%, adhesive 1.0 %, modifier 2.0%.

The bitumen-polymer mastic described in the invention has a universal character in terms of its application both for the formation of insulating coatings directly on the pipeline (or on the pipe), and for the creation of semi-finished products (blanks for coatings), in particular, for the manufacture of polymer-bitumen tape materials.

Claims (2)

1. Insulating bitumen-polymer mastic for anticorrosive protective coatings of underground pipelines, including a mixture of bitumen, thermoplastic elastomer, plasticizer and filler, characterized in that as a bitumen a mixture of bitumen BND-60/90 and BNI-4 or BN-70/30, Divinyl styrene thermoplastic elastomer was used as a thermoplastic elastomer, and a modifier, an oil-polymer resin and an adhesive additive were added to the mastic, the mastic having the following composition of components, wt.%: BND-60/90 bitumen 8.5-90, BN bitumen -4 1-20 or bitumen BN-70/30 1-90, divinyl styrene thermoplastic elastomer 1,5-5, plasticizer 1-5, filler 1-8, petroleum resin 2-8, adhesive additive 0.3 -1.5, modifier 1-6. 2. A method of manufacturing a mastic according to claim 1, comprising mixing bitumen, thermoplastic elastomer, plasticizer and filler, characterized in that the mixing of the components of the mastic is performed as follows: first prepare a mixture of road and insulating bitumen or building bitumen, then by heating to a temperature of 160- 170 ° C dehydrate this mixture, a mixture of bitumen is fed into the mixer and added to the last plasticizer, the resulting mixture is stirred at a temperature of 165-175 ° C for 2.5-3.5 hours until the plasticizer is completely dissolved, yes it is added a filler, such as crumb rubber, and the resulting mixture was stirred 25-35 min, after which stirring was continued and added petroleum resin modifier, an adhesion agent and a thermoplastic elastomer.