Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
  • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
  • H04R31/003—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor for diaphragms or their outer suspension
• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
  • G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
  • G09G5/22—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators characterised by the display of characters or indicia using display control signals derived from coded signals representing the characters or indicia, e.g. with a character-code memory
  • G09G5/222—Control of the character-code memory

Definitions

• the invention relates to films or membranes for acoustic applications which must have specific vibrational properties, in particular to membranes for electro-mechanical transducers capable of transforming an electric current received into sound emission (loudspeakers) or conversely a sound wave received into current electric transmission (microphones), in particular for loudspeakers, and to the process for preparing such films or membranes.
• the object of the invention is precisely to provide improved films or membranes for various acoustic applications.
• the subject of the invention is firstly a process for preparing a film or membrane for acoustic applications having improved vibratory properties, characterized in that a dispersion in a liquid of at least one macropolymer is prepared, in particular at least one synthetic macropolymer, comprising in its molecule at least 30,000 atoms, which is added to the dispersion a product capable of swelling said at least one macropolymer and of transforming said dispersion into a gel or the like and which is dried said gel or the like by evaporating substantially all of the liquid from the gel or the like to obtain the film or membrane in the porous solid state.
• the invention also relates to a porous film or membrane for acoustic applications, in particular a speaker membrane, having improved vibratory properties, characterized in that it comprises a first phase of formation of a gel or the like mistletoe results from the dispersion with dilution in a liquid of a macropolymer, in particular of a synthetic macropolymer, comprising in its molecule at least 30,000 atoms, followed by the addition to the dispersion of a product capable of transforming it into a gel or the like, and a second phase of evaporation of substantially all of the liquid from the gel or the like.
• the macropolymer consists of a polymer of ethacrylic acid, a polymer of ethyl acetate or a mixture of such polymers, in particular of the type sold by the company HOECHST under the brand "APPRETAN 9110".
• the macropolymer can also be polyvinyl acetate, a polyvinyl alcohol or more generally a polyvinyl polymer.
• Another macropolymer which can advantageously be used in the context of the invention is cellulose or one of its derivatives.
• the product added to the dispersion preferably:
• a basic, mineral such as ammonia
• organic liquid such as an amine
• a basic solid such as caustic soda
• a macropolymer of polyalcohol type for example of poly (vinyl alcohol) type, - ethyl acetate or tetrahydrofuran for a polyvinyl macropolymer.
• the gel before drying can either be impregnated on fabrics (woven or non-woven) or locks of natural, artificial or synthetic fibers, or constituting the binder of such fibers, with the possibility of adding fillers (carbon, ceramic, glass, graphite, etc.) in each case.
• the material thus obtained, once dried and become porous, can advantageously be thermoformed due to the flexibility of the dried material, once heated, and the thermal adhesion of the gel or the like dried on the fabrics or strands of fibers.
• APPRETAN 9110 is an aqueous dispersion of a mixture of macropolymers consisting of 70% of methacrylic acid polymer (or polymethacrylate) and 30% of ethyl acetate polymer (or poly (ethylacetate )), with a dry extract of 32.50% of the mixture of copolymers relative to the dispersion.
• the starting point is an aqueous dispersion containing 15% polyvinyl acetate; it is placed on a nylon canvas; the water is evaporated; and the canvas thus coated is dipped in ethyl acetate.
• a gel having the consistency of honey is obtained, which is dried with hot air to produce the evaporation of the ethyl acetate.
• Example 1 For example for a membrane 17 cm in diameter, the mass in the case of the application of Example 1 is 1.75 g, while it is of the order of 2.5 to 5 g for a membrane obtained from the starting aqueous dispersion of Example 1 not treated with ammonia or produced from the materials normally used, namely paper, polypropylene or suitable composite.
• the ethyl acetate is evaporated, also with hot air.
• the membrane thus obtained is particularly suitable for producing an electro-acoustic transducer membrane, in particular for a loudspeaker for the medium and acute channels.
• Ammonia is added dropwise until a gel is obtained.
• the gel thus obtained is mixed with appropriate fibers or fillers (carbon, glass, mica, kevlar, graphite) and is shaped.
• a bath of the same mother liquor of APPRETAN 9110 is prepared (dry extract of 32.50%) which is diluted in water at the rate of 15% and it is gelled by adding ammonia drop by drop.
• Carbon fibers are poured into the gel formed and dispersed therein in a manner homogeneous in a mixer.
• the homogenized mixture thus obtained is passed under pressure through a sieve which retains the fibers impregnated with gel, which are dried on the sieve with hot air.
• the shape thus obtained is removed from the sieve.
• this form of membrane is not waterproof, it is sealed by applying a coating, such as butyl latex, or by heat bonding a sheet of waterproof thermo-adhesive polymer, such as "LITREX S "(polyethersulfone) from the company P.CD.
• a coating such as butyl latex
• a sheet of waterproof thermo-adhesive polymer such as "LITREX S "(polyethersulfone) from the company P.CD.
• the invention is not limited to the embodiments or to the compounds indicated and specified, in particular in the examples, in particular to macropolymers, on the one hand, and to stabilizing liquids, on the other hand , or any additives, but it includes modifications and variants within the reach of ordinary skill in the art, including in this regard, the means of applying the product obtained according to its destination in various uses.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Manufacturing & Machinery (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• General Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Theoretical Computer Science (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Toys (AREA)
• Piezo-Electric Transducers For Audible Bands (AREA)

Priority Applications (8)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9398990

Family Applications (1)

Country Status (13)

Families Citing this family (1)

Citations (5)

Family Cites Families (10)

• 1990
  • 1990-07-23 FR FR9009369A patent/FR2665321A1/fr active Pending
• 1991
  • 1991-07-22 EP EP91913851A patent/EP0540622B1/fr not_active Expired - Lifetime
  • 1991-07-22 AT AT91913851T patent/ATE141739T1/de not_active IP Right Cessation
  • 1991-07-22 KR KR1019930700197A patent/KR100195826B1/ko not_active Expired - Fee Related
  • 1991-07-22 JP JP3512793A patent/JP3046351B2/ja not_active Expired - Lifetime
  • 1991-07-22 DE DE69121572T patent/DE69121572T2/de not_active Expired - Fee Related
  • 1991-07-22 DK DK91913851.1T patent/DK0540622T3/da active
  • 1991-07-22 WO PCT/FR1991/000603 patent/WO1992002108A1/fr not_active Ceased
  • 1991-07-22 CA CA002087432A patent/CA2087432A1/fr not_active Abandoned
  • 1991-07-22 ES ES91913851T patent/ES2044819T3/es not_active Expired - Lifetime
  • 1991-07-22 US US07/969,801 patent/US5380960A/en not_active Expired - Fee Related
  • 1991-07-22 DE DE91913851T patent/DE540622T1/de active Pending
• 1992
  • 1992-01-11 TW TW081100162A patent/TW203658B/zh active
• 1994
  • 1994-04-29 GR GR940300018T patent/GR940300018T1/el unknown
• 1996
  • 1996-11-14 GR GR960402995T patent/GR3021624T3/el unknown

Patent Citations (5)

Non-Patent Citations (2)

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