FR2477610A1 - PHONIC ISOLATION CARPET AND METHOD OF PRODUCING THE SAME - Google Patents

Abstract

THE INVENTION CONCERNS A SOUND INSULATION CARPET AND ITS PRODUCTION PROCESS. THE SOUND INSULATION CARPET ARTICLE OF THE INVENTION INCLUDES A CARPET WITH A REAR SURFACE, AND A COMPOSITION LINKED TO THE said REAR SURFACE, THIS COMPOSITION CONTAINING A POLYOLEFIN, B A COPOLYMER RUBBER OF ETHYLENE AND A-O-OLEFIN. OR OF A MONOVINYL AROMATIC HYDROCARBON AND A CONJUGATE DIOLEFIN, C PETROLEUM OIL, AND AN INORGANIC FILLER. APPLICATION TO SOUND INSULATION, FOR EXAMPLE OF THE FLOOR OF A MOTOR VEHICLE.

Description

1. The present invention relates to a carpet or carpet endowed with very good

  sound insulation characteristics, in particular for covering the floor of a motor vehicle. The invention relates in particular to a carpet or sound insulation carpet which is very flexible and easy to achieve by injection molding, extrusion, etc. The invention more particularly relates to carpets or carpets whose structure comprises an implanted pile primary web and a dense bound sound insulation composition, serving as a support. The invention furthermore relates more particularly to methods for producing insulating mats. It is known to cover the floor of a motor vehicle with a carpet stopping or absorbing any noise from the underside of the motor vehicle, its engine or a similar part, to improve comfort when the vehicle is en-route. A carpet known for the floor covering of a motor vehicle is a carpet whose support is formed of a polyolefinic resin such as a polyethylene and a copolymer of ethylene and vinyl acetate. The support material, however, has a low basis weight and fails to provide satisfactory sound insulation, since it does not contain a load or contains only a little. In order to improve the sound insulation of such a carpet, it has been proposed to use a support material containing a

  large amount of a very dense charge.

  The addition of a large amount of a filler to a polyolefin, however, results in a marked reduction in its melt flow characteristics, and makes it difficult to mold in an injection molding machine, extruder, and the like. , because an extremely large torque is required. The support material thus obtained forms a molded product of uninviting appearance, and since this product has a large flexural modulus, it lacks flexibility and is brittle, and it fails to adhere firmly to a carpet when it is used as a support for the latter. A material of this type, with a high flexural modulus, is not an advantage for sound insulation, since its frequency of coincidence

the audible range.

  Among other polyolefins, an ethylene-vinyl acetate copolymer with a high vinyl acetate content is flammable, has a low melting point and is low in heat even though it contains a large amount of a filler. The present invention provides a carpet or soundproofing carpet which constitutes a carpet having a posterior surface and a composition bonded to said posterior surface of the carpet, formed of a polyolefin, a synthetic rubber, a petroleum oil and an inorganic filler having a density of at least 1.5 and a flexural modulus of not more than 500 MPa. The carpet of the invention has very good sound insulation and flexibility characteristics and has the required properties of a carpet. The soundproofing carpet of the invention can be made more particularly in various forms, each comprising the composition defined above, linked to the posterior surface of the carpet. In one embodiment, a needled carpet is obtained by needling the fibers of the carpet on a primary web formed for example of jute, synthetic fibers and a flat yarn. In another embodiment, curly hairs are implanted in the primary web and in a third embodiment, cut hairs are

implanted in the primary web.

  In a preferred embodiment, the composition comprises a synthetic rubber in the proportion of 5 to 400 parts by weight per 100 parts by weight of the polyolefin. In one embodiment, the rubber

  synthetic material is preferably an ethylene-a-

  olefin, for example an ethylene-propylene rubber or a terpolymer of ethylene and an α-olefin, for example a

  ethylene-propylene-ethylidenenorbornene copolymer, ethylene-

  propylene-dicyclopentadiene or ethylene-propylene-1,4-

  3. hexadiene. In another preferred embodiment, the

  synthetic rubber comprises a copolymer of a hydro-

  monovinyl aromatic carbide and a diolefin

  conjugated, for example a styrene-butadiene rubber.

  In another embodiment, the polyolefinic component is a homopolymer of an α-olefin, such as polypropylene. In another embodiment, the

  polyolefin is an ethylene-propylene block copolymer.

  In yet another preferred embodiment, the petroleum oil is a paraffinic softening oil. In another embodiment of the invention, the composition comprises an inorganic filler at a concentration which gives the composition a density of at least 1.5. In a preferred embodiment, the inorganic filler is a particle powder having a diameter of not more than 150 microns and in another preferred embodiment, the inorganic filler consists of

barium sulfate.

  In another preferred embodiment, the composition is extruded and laminated to the rear surface of a carpet, and in a particularly preferred embodiment, the composition has a thickness

at least 0.5 mm.

  The present invention may be made more particularly in various forms comprising: (1) a needlelayer sound insulation carpet comprising the composition having a density of at least 1.5 and a flexural modulus of not more than 500 MPa, and bonded to the

  posterior surface of a carpet obtained by needle

  threading of fibers on a primary fabric, for example in jute, synthetic fibers and flat yarn; (2) a loop pile pile carpet comprising the composition having a density of at least 1.5 and a flexural modulus not exceeding 500 MPa and bonded to the posterior surface of a carpet obtained by implantation of hair curls on a primary fabric, for example jute, synthetic fibers and a flat yarn; 4. (3) a carpet similar to that defined in (2),

but who wears cut hairs.

  For the purposes of the present invention, the carpet may be a known carpet of the type obtained for example by implantation of curly or cut hairs on the anterior surface of a primary fabric mainly made of jute, synthetic fibers, a flat yarn,

etc., and a needle-punched carpet.

  The composition to be used in accordance with

  according to the invention, comprising a polyolefin, a synthetic rubber, an oil derived from petroleum and an inorganic filler and having a density of at least 1.5 and a flexural modulus of not more than 500 MPa, may contain 5 to 400 parts by weight of the synthetic rubber per 100 parts by weight of the polyolefin, 5 to 100 parts of the petroleum oil for a total of 100 parts by weight of the polyolefin and the synthetic rubber, and the amount of inorganic filler which is necessary to allow the composition to have a density of at least 1.5 and a modulus of

bending not exceeding 500 MPa.

  The polyolefin may be a homopolymer of

  olefin or a crystalline copolymer mainly formed of this homopolymer, for example polyethylene, polypropylene,

  polybutene-1, poly-4-methylpentene-1, an ethylene-

  propylene, for example a block copolymer ethylene-

  propylene, an ethylene-butene-1 copolymer, a propylenebutene-1 copolymer, an ethylene-vinyl acetate copolymer and an ethylene-ethyl acrylate copolymer. Polypropylene and a block copolymer of ethylene and propylene are particularly preferred. It is possible to use only one such polyolefin or a mixture of two or

several polyolefins.

  The synthetic rubber may be an ethylene-olefin copolymer, a terpolymer or other copolymer comprising ethylene, anolefin and one or more dienes, or a copolymer of a monovinyl aromatic hydrocarbon and a conjugated diolefin. It may have an ethylene content of 20 to 80% by weight, a diene content of 5 to 40% by weight, a monovinyl aromatic hydrocarbon content of 20 to 80% by weight, and a Mooney viscosity of 5 to 10% by weight. Examples of such a rubber include ethylene-propylene rubber, ethylene-butene-1 copolymer, ethylene-propylene terpolymer, and the like.

  ethylidenenorbornene, an ethylene-propylene terpolymer

  dicyclopentadiene, an ethylene-propylene-1,4-terpolymer

  hexadiene, a styrene-butadiene block copolymer and a styrene-butadiene random copolymer. We appreciate

  particularly an ethylene-propylene rubber.

  The petroleum oil may be a hydrocarbon having a boiling point of at least 3500C. for example a paraffinic, naphthenic or aromatic fraction of high boiling point oil. A paraffinic fraction is particularly preferred. A softening oil counts

among these oils.

  The inorganic filler can be selected from metals, metal compounds, silicates and silicate-bearing minerals, and materials which are chemically stable under ordinary conditions of use. More particularly, the inorganic filler may be, for example, a metal such as iron, zinc, nickel, chromium, lead, copper, molybdenum and manganese, an oxide, carbonate or sulphate of any one of these metals or barium, aluminum, titanium, calcium or magnesium, or talc, a clay, silica, mica,

  asbestos, silicic anhydride, etc. It is particularly

  It is advantageous to use calcium carbonate, barium sulfate, lead, iron, zinc or a compound of any of these metals. Barium sulfate is very preferable from the point of view of thermal stability. It is possible to use a single type of charge or a mixture of at least two charges. The filler may be formed of a powder, fibers, sheets, etc., but it is desirable to use a particulate powder having a diameter of not more than 150 μm, for reasons of processability. The amount of charge that must be incorporated depends on its density. If a load with a density of 2 is used, it is necessary to incorporate at least 260 parts by weight of

  parts by weight of a polymeric composition, i.e.

  say a combination of polyolefin, synthetic rubber and petroleum oil. Any quantity less than this value gives a sheet of density equal to or less than 1.5 and from which satisfactory properties of sound insulation are not to be expected. The upper limit of the amount of filler that can be incorporated can be raised to the maximum amount which is generally proportional to the density of the powder if the latter is formed of particles whose diameter is equal to or less than 150 micrometers. However, considering the transformability and flexibility of the composition in the molded state, not more than twice as much filler as polymeric composition should be incorporated on the basis of the actual volume ratio. It is therefore effective to incorporate within the above-defined range a charge amount having the maximum possible density so as to obtain a composition having a density large enough to produce a satisfactory sound insulation effect, while still retaining great transformability and flexibility. There is no particular limitation with regard to the method of binding to a carpet of a composition having a density of at least 1.5 and a flexural modulus of not more than 500 MPa, but it is possible to use a conventional method such as extrusion lamination and application of an adhesive. However, it is industrially convenient to melt the polymeric composition by heating, continuously extruding it through a die onto an extruder for lamination to the posterior surface of a

  carpet, and apply pressure to it with a roller.

  The amount of composition to be laminated depends on the purpose for which the carpet is intended, but generally, since a greater thickness produces a significant effect of sound insulation, it is desirable to laminate the composition to a thickness of at least 0, 5 mm and in particular of at least 0.8 mm

2 2477610

  7. (i.e., to such an extent that the carpet may have a surface density of at least 2 kg / cm 2). If appropriate, it is possible to incorporate a coloring agent, an antistatic agent, an antioxidant, a lubricant, an ultraviolet light absorbing agent, a heat stabilizing agent, a surfactant or the like agent. to the composition. As described above, the invention provides a carpet or carpet that has very good sound insulation and flexibility characteristics and that can be used not only in motor vehicles, but also

  in other vehicles and buildings.

  The invention is illustrated by the following examples, given in a non-limiting manner, in which all

  the parts are expressed by weight.

EXAMPLE 1

  (1) Preparation of the composition to be bound to a carpet Various compositions are prepared by loading various proportions, as indicated in Table I, of polypropylene (PP) with a melt index at 2300 C equal to 22,

  in accordance with ASTM D-1238, an ethylene-

  vinyl acetate (EVA) with a melt index of 190WC equal to 20, an ethylene-propylene rubber having an ethylene content of 70% by weight and a Mooney viscosity equal to 70, of barium sulfate (BaSO4) in particles with a mean diameter of 7 μm and a softening paraffinic oil (R-1000 oil from Kyodo Sekiyu) in a Banbury mixer and kneading the ingredients for 10 minutes at a temperature of 190 to 2001C, the mixture being then cooled and crushed. Each of the compositions thus obtained was subjected to the density determination tests according to the

  JIS K-6758 standard, flexural modulus according to ASTM D-

  790, melting point by means of differential calorimeter <DSC) and flexibility. The results are reproduced in Table I. The flexibility of each composition was evaluated according to a test of bending and touching on a sheet of said composition having a thickness of 3 mm. In Table 1, a double circle means "very soft"; a simple

  circle means "soft"; and a cross means "hard".

  8. (2) Manufacture of sound insulation carpets Each of the compositions obtained in Tests 1 and 2 was extruded continuously in an extrusion molding machine and laminated to a thickness of 2.5 mm on the back surface. a needled carpet obtained by needling polypropylene fibers (800 g / m2) and reinforcement with a latex, followed by compression, of

to form a carpet.

  The carpets of the invention, obtained as described above, were compared with known carpets for motor vehicles, obtained by extrusion lamination of a low density polyethylene with a melt index of 5 and having a density of 0.912. on supports for carpets of the same type as those used for making the carpets of the invention. The carpets were put in place to cover the floor of a motor vehicle and they were compared on the basis of the noise perceived inside the motor vehicle when it rolls. The results are reproduced on the

Table I.

TABLE I

Trial number

(example

comparative)

(example

comparative)

(example

  comparative) PP EVA _ - EPR Properties of compositions intended to be bound to carpets BaSO4 Oil

ramol-

Reading Weight

spe-

  (g / cm3) 1.86 1.87 1.88 1.89 Flexural modulus (MPa) Melting point (C) (O> 151.8 153.2 161.5, 0)

Flexi

  bility __ O X O Carpet Rating Surface Density (kg / cm2), 45, 48 3.08 I - J.-.S. t _____________________ JJ I J J Noise inside a motor vehicle * (dB) NOTE: * Noise has been measured in a motor vehicle traveling at speed

  test apparatus integral with the chassis.

  100 km / h, in an oI -4 OI O> o 10.

EXAMPLE 2

  Compositions and carpets have been

  prepared and tested according to the

  of Example 1, with the difference that polyolefin, synthetic rubber, petroleum

  The floor and carpet shown below were used.

  The results are shown in Table II.

  (1) Polyolefin (A) ethylene-propylene block copolymer having an ethylene content of 7% by weight and a

melting at 230 C equal to 9.

  (2) Synthetic rubber (B1) Styrene-butadiene block copolymer having a styrene content of 40% by weight and a Mooney viscosity of 24 (B2) Ethylene-propylene rubber having an ethylene content of 70% by weight and a viscosity Mooney equal to 70; or (B3) ethylene-propylene-ethylidenenorbornene terpolymer having a propylene content of 40% by weight, an ethylidenenorbornene content of 15% by weight and

  a Mooney viscosity equal to 105.

  (3) Petroleum oil (C1) Paraffinic softening oil; or

  (C2) Softening naphthenic oil.

  (4) Inorganic filler (D1) Zinc oxide in particles of average diameter not exceeding 1 μm (D2) Calcium carbonate in particles having an average diameter of 2 μm; (D3) Talc in particles of average diameter equal to 12 micrometers; (D4) powdered iron in particles of average diameter equal to pm; or (D5) Iron oxide particles having an average diameter of 1 μm. (5) Carpet Needled carpet (polypropylene fibers of

1.7 g / km; 800 g / m2).

TABLE II

  Properties of compositions for bonding to rubber carpets

synthetic

  ticks (parts) B1 (10) B1 (10) B2 (5) B2 (5) B3 (10) B3 (10) Petroleum oil (parts) C2 (10) C2 (20) C1 (10) C1 (10) C1 (10) C1 (10) Inorganic charge (parts) D1 (100) D1 (100) D2 (75) D3 (75) D4 (120) D5 (120) Weight

spe-

  (g / cm3) 2.03 2.02 1.79 1.68 2.66 2.33 Flexural modulus (MPa) Melting point (C) 154.1 152.9 156.3 158.4, 5 154.8

Flexi

  bility _O O O O O o o o o Evaluation of the carpet Density Noise from the inside surface of a (kg / cm2) car vehicle (dB)

, 88 64

, 85 64

, 28 65

, 00 66

7.45 62

6.62 63

3.08 74

  Polyolefin (parts) A (30) A (20) A (10) A (10) A (20) A (20) Test number

comparison

ratify e --j -4j 0 ,. 12.

EXAMPLE OF REFERENCE

  Table III shows the sound insulation characteristics measured on the carpets prepared in tests Nos. 2 and 9 and in the comparative example indicated in Table I. For the determination of the sound insulation effect of each carpet, the carpet was mounted on a loudspeaker in which the vibration generated by

  a transmitter has been converted into a noise by a loudspeaker.

  Noise from the loudspeaker was received by a microphone

  phone in a decibel meter placed in front of the speaker, and

  the sound pressure has been measured at various frequencies.

TABLE III

  Transmission loss (dB) (Needled carpet with a 25 mm thick sheet laminated to it1) Measuring frequency (s)

200 400 800 1000 2000 4000

17 14 16 25 25 33 38

12 18 27 25 36 41

<5 <5 10 15 16 23 29

C4 - 40% O 14.

Claims (16)

  1. - article with soundproofing carpet, characterized in that it comprises a carpet having a posterior surface, and a composition bonded to said posterior surface, this composition comprising (A) a polyolefin, (B) a rubber copolymer d ethylene and α-olefin or a monovinyl aromatic hydrocarbon and a conjugated diolefin, (C) a petroleum oil, and (D) a inorganic filler.   2. - Carpet article according to the   cation 1, characterized in that the carpet is selected between a needled carpet, a pile velvet carpet and a carpet shaved velvet.   3. - Carpet article according to one of the   1 and 2, characterized in that the posterior surface is formed of a primary fabric selected from jute, fibers synthetic and flat spun.   4. - Carpet article according to any one of   Claims 1 to 3, characterized in that the composition has a density of at least 1.5.   5. - Carpet article according to any one   Claims 1 to 4, characterized in that the composition   has a flexural modulus not exceeding 500 MPa.   6. - Carpet article according to any one of   Claims 1 to 5, characterized in that the polyolefin   is a polypropylene or a block copolymer ethylene-   propylene. 7. - Carpet article according to any one   Claims 1 to 6, characterized in that the rubber   ethylene-α-olefin is selected from an ethylene-   propylene, an ethylene-propylene-ethylidene terpolymer   norbornene, an ethylene-propylene-dicyclo terpolymer   pentadiene and an ethylene-propylene-1,4-terpolymer   hexadiene. 8. - Carpet article according to any one of   Claims 1 to 7, characterized in that the oil of   oil is chosen between paraffin-   fine, naphthenic and aromatic.   15. 9. - Carpet article according to any one   Claims 1 to 8, characterized in that the load   inorganic is chosen between calcium carbonate, barium sulfate and oxides, carbonates and sulphates of lead, iron and zinc.   10. - Carpet article according to the   cation 9, characterized in that the inorganic filler is a powder in particles of average diameter not exceeding micrometers.   11. - Carpet article according to the   cation 10, characterized in that the ratio of the volume of the inorganic filler to the sum of the volumes of the components (A),   (B) and (C) is less than or equal to 2.   12. - Carpet article according to any one of   Claims 1 to 11, characterized in that the thickness   of the composition related to the posterior surface is at least 0.5 mm.   13. - A method of producing a soundproof carpet article according to any one of   Claims 1 to 12, characterized in that it consists of   taking a primary fabric having a posterior surface and an anterior surface, preparing a sound-insulating composition comprising (A) a polyolefin, (B) a copolymer rubber of ethylene and an α-olefin or copolymer of a hydrocarbon monovinyl aromatic and a conjugated diolefin, (C) a petroleum oil, and (D) an inorganic filler, to implant carpet fibers into the anterior surface and to bind said composition to said posterior surface.   14. - Process according to claim 13,   characterized in that the composition is melted by applying   heat cation, extruded and laminated to the surface   posterior by applying pressure.   15. - Method according to one of claims 13   and 14, characterized in that the thickness of the composition on   the posterior surface is at least 0.5 mm.   16. - Process according to any one of   Claims 13 to 15, characterized in that it consists of   16. Mold the carpet item to the desired shape by application of heat and pressure.