RU2622053C1 - Composition for manufacturing panels of sound-absorbing screens by extrusion method - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: composition for manufacturing panels of sound-absorbing screens by extrusion method includes isotactic polypropylene, a granular extrusion product of isotactic polypropylene with a m-phenylene-bis-maleimide modifier at their weight ratio of 8.5:1.0 to 9.0:1.0 and a fibrous filler, which is represented by basalt fibers treated with a water-compatible silane-containing lubricant, at the following ratio, wt %: isotactic polypropylene 67.0-70.0, the granular extrusion product of isotactic polypropylene with the modifier based on m-phenylene-bis-maleimide 0.8-1.2, fibrous filler - the rest.

EFFECT: improvement of physical and mechanical properties of panels of sound-absorbing screens.

1 tbl, 4 ex

Description

The invention relates to materials for the manufacture of noise barriers installed along roads, railways, around industrial facilities and other noise sources.

The effectiveness of sound-absorbing screens is determined not only by the sound-absorbing and sound-insulating properties of the materials from which they are made, these materials must have high physical and mechanical properties, in particular: mechanical strength, resistance to stone shocks, protection against electric shock from personnel and the public.

Known compositions for the manufacture of sound-absorbing screens, including a thermoplastic polymer - polyethylene, polypropylene, polyvinyl chloride, polyamide, polymethyl methacrylate and others, and a fibrous filler - glass, basalt, carbon and other fibers (RU 2173372 C2, RU 156212 Ul, RU 2005105431 A, RU 21733331 A, RU 21733331 A, RU 21733331 A, RU 21733331 A, RU 217337231 A, RU 217337231 A, RU 217337231 A, RU C2, RU 2015 148 C1, CN 103897262 A).

Sound-absorbing panels can be injection molded. However, this method has insufficient productivity, it does not allow to obtain products of continuous length having strictly the same thickness over the entire area, which, in turn, does not allow to organize a continuous high-performance process for the manufacture of panels of sound-absorbing screens.

The extrusion panels are exactly the same in thickness at all points, have a flat end, the advantage of the extrusion method is high productivity and the ability to obtain products of continuous length. However, during the extrusion process, the components of the composition are exposed to high temperatures and shear stresses, which leads to a change in their structure, technological properties of the composition and can have a negative effect on the physicomechanical properties of the resulting product. In this regard, special requirements are imposed on the composition of the composition intended for extrusion molding.

A known composition for the manufacture of panels of noise barriers by extrusion, including a thermoplastic polymer - polymethyl methacrylate and a fibrous filler - polyamide yarn (EP 1606457 B1).

However, panels made from the known composition have sound-reflecting properties, which is unacceptable due to the high noise level directly on the highways.

Closest to the proposed invention is a known composition for the manufacture of panels of sound-absorbing screens by extrusion, comprising isotactic polypropylene and a fibrous filler (DE 102012100567 A1). As a fibrous filler, the known composition includes lignocellulosic fibers in an amount of 50-85% by weight of the composition.

A disadvantage of the known composition is the low physical and mechanical properties of the panels of sound-absorbing screens made from it.

An object of the invention is to provide a composition for the manufacture of panels of sound-absorbing screens by extrusion, devoid of this drawback.

The technical result of the invention is to improve the physico-mechanical properties of the panels of sound-absorbing screens.

The specified technical result is achieved by the fact that the composition for the manufacture of panels of sound-absorbing screens by extrusion, including isotactic polypropylene and a fibrous filler, further comprises a granular product of extrusion of isotactic polypropylene with a modifier based on m-phenylene-bis-maleimide at a mass ratio of 8.5: 1.0 to 9.0: 1.0, respectively, and as a fibrous filler includes basalt fiber treated with a water-incompatible silane-containing sizing, pr the following component ratio, wt. %:

isotactic polypropylene 67.0-70.0 granular extrusion product of isotactic polypropylene with a modifier based on m-phenylene-bis-maleimide 0.8-1.2 fiberfill rest

As a fibrous filler, the proposed composition includes treated with any water-incompatible silane-containing lubricant sizing basalt fiber. Such basalt fiber treated with a water-incompatible silane-containing sizing agent is commercially available or it can be prepared, for example, according to RU 2167838 C1, using sizing No. 4C (GOST R 53237-2008) or such as described in http://www.korsil.ru/ silan-zamaslivatel.html, RU 2101241 C1, RU 2389698 C1, SU 1666480 A1, etc.

Processing basalt fiber with a water-incompatible silane-containing sizing agent increases the antistaticity that counteracts the adhesion of the fibers, eliminating the electrification of the fiber by friction with the working bodies of the extruder.

The result of using basalt fiber as a fibrous filler treated with a water-incompatible silane-containing sizing agent is an increase in the physicomechanical properties of the panels of sound-absorbing screens made of the proposed composition by extrusion.

Another factor that improves the physicomechanical properties of panels of sound-absorbing screens made by extrusion of the proposed composition is the use of 0.8-1.2 wt. % of an additional component - a granular product of extrusion of isotactic polypropylene with a modifier based on m-phenylene-bis-maleimide, prepared at their mass ratio from 8.5: 1.0 to 9.0: 1.0, respectively.

The granular product of extrusion of isotactic polypropylene with a modifier based on m-phenylene-bis-maleimide is obtained previously. Isotactic polypropylene is mixed with a modifier based on m-phenylene-bis-maleimide at a weight ratio of 8.5: 1.0 to 9.0: 1.0, respectively. Then the resulting dry mixture is passed through an extruder at a maximum melt temperature of 200 ° C. The strands extruded from the extruder with a diameter of 3-4 mm are cooled in a water bath and cut into granules 3-4 mm long. The obtained granulate is dried at a temperature of about 80 ° C for at least 2 hours. As a modifier, any modifier based on m-phenylene-bis-maleimide can be used (Chemical additives to polymers. M., Chemistry, 1981, P. 177-178; RU 2569544 C1; http://libweb.kpfu.ru/ z3950 / EPOS_ESIC / Halikova_komp.pdf and others).

The result of extrusion of a mixture of isotactic polypropylene with a modifier based on m-phenylene-bis-maleimide is a product whose physicomechanical and technological properties differ from the properties of the product obtained by simple mixing, since during the extrusion the initial components are exposed to high temperatures and shear stresses, which contributes to a change in their structure as a result of ongoing mechanochemical processes. In the subsequent manufacture of panels of sound-absorbing screens by extrusion (purpose of the proposed composition), the granular product of extrusion of isotactic polypropylene with a modifier based on m-phenylene-bis-maleimide undergoes a repeated extrusion cycle. It is known that repeating extrusion cycles lead to significant changes in the molecular structural characteristics of vinyl polymers, which include polypropylene (http://www.dissercat.com/content/izmeneniya-struktury-i-svoistv-polimerov-vinilovogo-ryada-pri -mnogokratnoi-ekstruzii). It was experimentally confirmed that the presence in the composition of the material of the panels of sound-absorbing screens of the specified product of the repeated extrusion cycle in an amount of 0.8-1.2 wt. % significantly improves the physical and mechanical properties of panels of sound-absorbing screens.

It was experimentally confirmed that the result of using basalt fiber as a fibrous filler in the composition of the proposed composition, treated with any water-incompatible silane-containing sizing agent, and additional introduction of the above granular isotactic polypropylene extrusion product with any modifier based on m-phenylene-bis-maleimide into its composition leads to combined effect, characterized by an excess of the action exerted by each of the components individually, i.e. e. to the synergy effect. Such an effect is observed only in the above narrow range of ratios of the starting components of the proposed composition. Outside the specified range of ratios of the starting components, the synergy effect is absent.

Example 1

Preliminarily, a granular product of extrusion of isotactic polypropylene with a modifier based on m-phenylene-bis-maleimide is obtained in the manner described above with a mass ratio of components of 9.0: 1.0, respectively. As a modifier based on m-phenylene-bis-maleinimide, the industrial modifier Maleid F according to TU 6-14-1004-87 (http://ntcp.ru/work/library/5103/5211) is used. The specified granular extrusion product, isotactic polypropylene and basalt roving treated with a water-incompatible silane-containing lubricant manufactured by Kamenny Vek LLC (http://www.b-composites.net/26.html) is fed to the extruder in the following ratio of components, wt. %:

isotactic polypropylene 69.0 granular extrusion product of isotactic polypropylene with a modifier based on m-phenylene-bis-maleimide 1,0 fiberfill rest

The process is carried out in a twin-screw extruder with a screw diameter of 60 mm and a dyne to diameter ratio of 15 at 240-245 ° C. Strands with a diameter of about 4 mm emerging from the extruder are cooled in a bath with water and chopped on a granulator into segments 3-5 mm long. Then, the obtained granules are dried in a drum-type vacuum dryer at 75-85 ° C and a residual pressure of 0.4-0.6 kgf / cm ^{2 for} at least 4 hours.

The panels of sound-absorbing screens in the form of profiled sheets with a thickness of 3 ± 0.1 mm and a width of 500 ± 1 mm are made by extrusion using a single-screw extruder, at the output of which a profiling die is installed.

The test results of the obtained samples of panels of sound-absorbing screens showed a noise reduction of 40 dBA, which confirms the possibility of realizing the purpose of the proposed composition. Indicators of physical and mechanical properties of the obtained samples, demonstrating the achievement of a technical result, are shown in the table.

Example 2

The process is carried out as in example 1, but as a fibrous filler, the composition includes non-sizing basalt roving.

Example 3

The process is carried out as in example 1, but in the composition there is no granular product of extrusion of isotactic polypropylene with a modifier based on m-phenylene-bis-maleimide. The ratio of components, wt. %: isotactic polypropylene - 70, basalt roving treated with a silane sizing, produced by Kamenny Vek LLC (http://www.b-composites.net/26.html) - 30.

Example 4

The process is carried out as in example 1, but the composition of the composition does not contain a granular product of extrusion of isotactic polypropylene with a modifier based on m-phenylene-bis-maleimide, as a fibrous filler, it contains basalt roving not treated with a sizing agent. The ratio of components, wt. %: isotactic polypropylene - 70, basalt roving - 30.

In addition, comparative tests were carried out on samples made according to the method of example 1 from a composition according to DE 102012100567 A1 (prototype) using wood shavings as a lignocellulosic fibrous filler.

Indicators of physical and mechanical properties of the samples obtained according to examples 1-4, and the results of comparative tests are shown in the table.

Claims (2)

Composition for the manufacture of panels of sound-absorbing screens by extrusion, comprising isotactic polypropylene and a fibrous filler, characterized in that it further comprises a granular product of extrusion of isotactic polypropylene with a modifier based on m-phenylene-bis-maleimide at a mass ratio of 8.5: 1, 0 to 9.0: 1.0, respectively, and as a fibrous filler includes basalt fiber treated with a water-incompatible silane-containing sizing agent, in the following ratio onents, wt.%: isotactic polypropylene 67.0-70.0 granular isotactic extrusion product polypropylene with a modifier based on m-phenylene-bis-maleinimide 0.8-1.2 fiberfill rest