RU2258718C1 - Rubber compound for manufacturing acoustic layer of a coating - Google Patents

Abstract

FIELD: rubber industry.

SUBSTANCE: invention relates to manufacture of multilayer sound-absorbing polymer coatings. Rubber compound of invention comprises, wt parts: cis-isoprene rubber SKI-3 100, thiuram 1.5-2.0, vulcanization accelerators altax 1.5-2.0 and captax 1.2-1.5, anti-ageing agent Naftam-2 1.2-1.5, zinc oxide 10-12, stearic acid 1.5-2.0, and carbon black T-900 12-20. Such rubber compound allows formation of acoustic layer of coating, which is operable within sound frequency range from 5 to 1000 Hz and has dynamic shear modulus between 0.5 and 1.0 MPa.

EFFECT: improved performance characteristics of coating.

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Description

The present invention relates to polymeric materials with acoustic (sound-absorbing) properties used in the rubber industry for the manufacture of elements of polymer sound-absorbing coatings and products, in particular for shipbuilding facilities.

The property of polymer products and structures to absorb the energy of sound waves is characterized by the sound absorption coefficient, which is determined from the ratio of the absorbed energy of the sound wave to the energy of the incident sound wave. The property of polymer materials to absorb the energy of sound waves is characterized by a damping coefficient. Acoustic characteristics are associated with some indicators of the quality of polymeric materials. For example, the values of the natural frequency of longitudinal vibrations of samples and the attenuation coefficient are sensitive to changes in the composition of the feedstock and the manufacturing technology of polymer materials, which allows these indicators to be used to select the optimal technology and quality control of the workpieces (Encyclopedia of Polymers, vol. 1, M .: 1972, p. .58).

There are various technical solutions for the creation of soundproof and sound absorbing polymeric materials. The acoustic laminate as a wall coating (US Patent 5681408, IPC E 04 D 1/84, publ. 10/28/1997; РЖ 99.14-19Т.256П) is made by the method consisting in the use of adhesive paste penetrating into an acoustic laminate having channels and obtained from a woven fiber glued with a porous fiber in separate sections with a thermoplastic polymer binder, and this fabric has a coating of PVC plastisol. The same paste is applied to the back of the fabric and glues the acoustic material to the wall.

Soundproof polyurethane foams (PUF) with a density of 60-67 kg / m ³ and a loss factor of 0.2-0.55 (according to ISO 7626, part 1, 2) are obtained by the method declared by BASF AG (Application 10044712 Germany, IPC C 08 G 18/48, published on March 21, 2002; RZh 03.06-19T.169P). The named PUFs are obtained from aromatic polyisocyanates or their prepolymers with 16-44% NCO groups and a mixture of simple PEF in the presence of diols, triols and coloring pastes. Plastisol with acoustic action (Patent 2155780 Russia, IPC C 08 L 27/06, publ. 10.09.2000), intended for coating metal surfaces, for example on car bottoms, as a silencer, includes a suspension copolymer of vinyl chloride and vinyl acetate, a plasticizer , adhesive additive, filler and, if necessary, target additives. The sound-absorbing material according to Russian patent No. 2185765 (claims 34-40 of the claims, publ. 07/27/2002) contains the main material, which includes at least one polymer selected from the group of polar polymers consisting of polyvinyl chloride, chlorine-containing polyethylene, acrylic rubber, acrylonitrile butadiene rubber, styrene butadiene rubber and chloroprene rubber.

The objective of the invention is the creation of a rubber mixture for the manufacture of an acoustic layer in a two- or three-layer polymer coating, representing an independent molded product in the form of a plate, comprising a hard reinforcing layer (AR) and a soft acoustic (AK) sound-absorbing layer. A similar design of the acoustic coating is protected by RF patent No. 2161825, IPC G 10 K 11/00, 11/16, publ. 01/10/2001.

In the rubber industry for testing rubbers and rubbers (Reznikovsky MM, Lukomskaya AI Mechanical tests of rubber and rubber. M .: Chemistry, 1968) there are no direct methods and devices for determining the attenuation coefficient of sound waves in polymeric materials. To assess the acoustic properties of polymeric materials from the methods given in the book, you can use the dynamic modulus of rubber (p.234), which characterizes the dynamic elasticity of rubber. The attenuation coefficient of sound waves in rubber and the dynamic modulus of rubber are inversely proportional. It is known to use a rubber shear modulus for determining sound loss in rubber (Rubber shear modulus is an ultrasound approach: "Kautschuk und Gummi. Kunstst.", 2002, No. 3, pp. 114-117, German; RZ 03.05-19U.76 )

According to technical requirements for the acoustic layer of sound-absorbing coatings, similar to those protected by the aforementioned RF patent No. 2161825, operating in the range of sound frequencies from 5 to 1000 Hz, the dynamic shear modulus of the material of the acoustic layer should be in the range 0.5-1.0 MPa.

The aim of the present invention is the creation of a rubber compounding for the manufacture of an acoustic coating layer, providing dynamic shear modulus of vulcanizates (rubber) in the range from 0.5 to 1.0 MPa.

This goal is achieved in that the rubber mixture includes cis-isoprene rubber SKI-3, a vulcanizing system containing tiuram, altax, captax, and additionally, an antioxidant naphtham-2, zinc oxide, stearic acid, carbon black brand T 900, in the following ratio components, parts by weight:

Cis-isoprene rubber SKI-3 100 Tiuram 1.5-2.0 Altax 1.5-2.0 Kaltax 1.2-1.5 Antioxidant Naftam-2 1.2-1.5 Zinc oxide 10-12 Stearic acid 1.5-2.0 Carbon black T 900 12-20

The proposed rubber mixture for the manufacture of an acoustic coating layer differs significantly from the above analogues - sound-absorbing materials.

The closest analogue in composition (prototype) is the rubber mixture according to the patent of the Russian Federation No. 2034873 (publ. 05/10/1995), including 1,4-cis-polyisoprene rubber, a vulcanizing system containing sulfur and a vulcanization accelerator, zinc oxide, stearic acid, carbon black used in tire manufacturing.

A distinctive feature of the proposed technical solution from the prototype is a vulcanizing system containing thiuram, altax, captax, and in addition - naphtha-2 antioxidant, carbon black with improved properties, and the rubber mixture is intended for the manufacture of an acoustic layer of a sound-absorbing coating.

Table 1 shows the compositions of the rubber compounds of the prototype and variants of the inventive mixture.

Table 2 shows the physico-mechanical parameters of vulcanizates from rubber compounds shown in table 1.

As can be seen from table 1, and the inventive rubber compound and rubber compound prototype include isoprene rubber as a basis. For the inventive rubber compound, SKI-3 cis-isoprene rubber with good technological properties was selected (see, for example: Koshelev F.F., Kornev A.E., Bukanov A.M. General rubber technology. Edition. 4th, M., 1978, p. 54). Common components of these mixtures are zinc oxide, stearic acid and carbon black. A distinctive feature of the inventive rubber composition from the prototype is a vulcanizing system containing inactive carbon black, obtained by thermal decomposition of natural gas, with a low dispersion index and low structural index, carbon black brand T 900 (GOST 7885-86 Technical carbon for rubber production. Technical conditions )

From the data in tables 1 and 2, it can be seen that the optimal properties for the complex of acoustic, physico-mechanical and technological parameters have variants of the proposed rubber composition No. 3, 4, 5.

The proposed rubber mixture is prepared from domestic materials on conventional technological equipment in one stage with the introduction of the vulcanizing system in the last turn. The mixing time is 20-25 minutes. Vulcanization of the samples is carried out at a temperature of 151 ° C for 40 minutes.

Using the proposed rubber compound, samples of acoustic polymer coatings were made and tested. A positive assessment of the rubber compound was obtained by the Institute of the Central Research Institute named after Acad. A. Krylov. The rubber mixture is adopted for the manufacture of acoustic layers of polymer coatings operating in the range of sound frequencies from 5 to 1000 Hz.

Table 1
The composition of the rubber compounds, parts by weight Components Indicator value Prototype according to the patent of the Russian Federation 2034873 The proposed rubber compound 1 2 3 4 5 Cis-isoprene rubber SKI-3 100 100 100 100 100 1,4-cis-polyisoprene rubber 100 Vulcanizing system: Tiuram - 1,0 1,2 1,5 1.7 2.0 Altax - 1,0 1,2 1,5 1.7 2.0 Captax - 1,0 1,1 1,2 1.3 1,5 Antioxidant Naftam-2 - 0.8 1,0 1,2 1.4 1,5 Zinc oxide 4.8-5.2 8 nine 10 eleven 12 Stearic acid 1.8-2.2 1,0 1,2 1,5 1.7 2.0 Carbon black T 900 7 10 12 fifteen twenty Carbon black 30-40 Sulfur 2.0-2.5 - - - - - Vulcanization accelerator 0.5-0.9 - - - - - Oxide copolymers 2-6 - - - - - propylene and oxide divinyl

table 2
Properties of vulcanizates Indicators Indicator value Prototype according to the patent of the Russian Federation 2034873 Suggested tires 1 2 3 4 5 Dynamic shear modulus, MPa - 0.3 0.4 0.5 0.6 1,0 Conditional strength tensile, MPa 31.0-32.6 fifteen eighteen 19 19.5 twenty Relative extension at break,% 590-620 1000 950 900 850 750 Relative core precise elongation after break,% - 8 6 5 4 4 Shore Hardness Ah, units Shore a - twenty 25 thirty 33 35 Static module compression, when _{compression channel} E ε = 20% - 1.3 1,5 1.7 1.9 2.1 Time to start vulcanization (t ₅ ), min - 12 10 7 4 2 Note: Dash in the table - this indicator was not required.

Claims (1)

The rubber mixture for the manufacture of an acoustic coating layer, including SKI-3 cis-rubber, vulcanizing system, zinc oxide, stearic acid, T900 carbon black, while the vulcanizing system contains thiuram, altax, captax and optionally an antioxidant Naftam-2, in the following the ratio of components, parts by weight: Cis-isoprene rubber SKI-3 100 Tiuram 1.5-2.0 Altax 1.5-2.0 Captax 1.2-1.5 Antioxidant Naftam-2 1.2-1.5 Zinc oxide 10-12 Stearic acid 1.5-2.0 T900 carbon black 12-20