WO2022257783A1

WO2022257783A1 - Vibrating diaphragm for loudspeaker, preparation method for vibrating diaphragm for loudspeaker, and sound generating device

Info

Publication number: WO2022257783A1
Application number: PCT/CN2022/095650
Authority: WO
Inventors: 王婷; 闫付臻; 李春
Original assignee: 歌尔股份有限公司
Priority date: 2021-06-09
Filing date: 2022-05-27
Publication date: 2022-12-15
Also published as: CN113423045A; CN113423045B

Abstract

Disclosed in the present application are a vibrating diaphragm for a loudspeaker, a preparation method for a vibrating diaphragm for a loudspeaker, and a sound generating device. The vibrating diaphragm for a loudspeaker comprises an aqueous acrylate adhesive film layer and two plastic film layers, wherein one of the two plastic film layers covers one surface of the aqueous acrylate adhesive film layer, and the other plastic film layer covers the other surface of the aqueous acrylate adhesive film layer. The aqueous acrylate adhesive film layer is prepared from an acrylate emulsion, a curing agent, a wetting agent and a defoaming agent, and the molecular weight of an acrylate polymer in the acrylate emulsion is between two hundred thousand and two million. The acrylate polymer in the acrylate emulsion in the present application has a relatively high molecular weight, such that the prepared aqueous acrylate adhesive film layer has a relatively high high-temperature resistance, so that the vibrating diaphragm, prepared on the basis of the aqueous acrylate adhesive film layer, for a loudspeaker also has a relatively high high-temperature resistance.

Description

Diaphragm for loudspeaker, manufacturing method and sounding device for diaphragm for loudspeaker

technical field

The present application relates to the field of electroacoustic technology, and in particular to a diaphragm for a speaker, a method for preparing the diaphragm for a speaker, and a sound generating device.

Background technique

In the loudspeaker industry, many products in the industry are using composite materials of plastic layer and damping glue layer as the diaphragm for loudspeaker according to the consideration of product performance, listening and cost. The plastic layer can provide the stiffness required for the speaker diaphragm to vibrate, the damping rubber layer can provide the damping required for the speaker diaphragm to vibrate, and the damping adhesive layer can provide good adhesion, thus ensuring the speaker. The vibration consistency between the layers of the diaphragm. Among them, the acrylate pressure-sensitive adhesive film is widely used because of its excellent adhesion, damping property, simple application process and low cost.

At present, the acrylic pressure-sensitive adhesive films used in the industry are all made of solvent-based acrylic glue, which is processed by coating. However, a large amount of organic solvents volatilize during the coating process, thereby causing serious pollution to the environment. Moreover, the acrylate pressure-sensitive adhesive prepared by solvent-based acrylate glue, because the molecular weight of the acrylate polymer is generally within 200,000, the high temperature resistance of the prepared speaker film material is low, which further leads to the formation of the speaker. The high temperature resistance of the diaphragm is low. However, with the development of loudspeaker products towards high power, the high temperature resistance performance of the loudspeaker diaphragm is getting higher and higher. Therefore, the existing solvent-based acrylic film cannot meet the usage requirements of the speaker diaphragm.

Contents of the invention

The main purpose of the present application is to provide a diaphragm for a speaker, a method for preparing a diaphragm for a speaker, and a sounding device, aiming at solving the technical problem that the currently prepared diaphragm has low high temperature resistance.

In order to achieve the above object, the embodiment of the present application provides a diaphragm for a speaker, the diaphragm for a speaker comprises a water-based acrylic film layer and two plastic film layers, one of the two plastic film layers covers the On one surface of the water-based acrylic film layer, another plastic film layer is covered on the other surface of the water-based acrylic film layer; wherein the water-based acrylic film layer is made of acrylate emulsion, solidified agent, wetting agent, and defoamer, and the molecular weight of the acrylate polymer in the acrylate emulsion is between 200,000 and 2 million.

Preferably, the plastic film layer comprises polyether ether ketone, polyarylate, polyetherimide, polyimide, polyphenylene sulfide, polyethylene naphthalate, polyethylene terephthalate One or more of alcohol esters and polybutylene terephthalate.

Preferably, the thickness of the water-based acrylate film layer is 5um to 50um.

Preferably, the glass transition temperature of the water-based acrylate film layer is -20°C to -60°C.

Preferably, the storage modulus of the water-based acrylate film layer at 150° C. is 0.01 MPa to 1 MPa.

Preferably, after the water-based acrylic film layer is treated in an environment of 60°C-70°C and 90%-98% humidity for 165 hours to 170 hours, the change in peel strength from the plastic film layer is less than 15%.

Preferably, the peel strength between the plastic film layer and the water-based acrylic film layer is greater than or equal to 150g/25mm.

Preferably, the adhesion holding force of the water-based acrylic film layer at 80°C*1h is less than or equal to 0.2mm.

In order to achieve the above object, the present application also provides a method for preparing a diaphragm for a loudspeaker, and the method for preparing a diaphragm for a loudspeaker includes:

Mix 100 parts by mass of acrylate emulsion, 0 to 5 parts by mass of curing agent, 0.1 to 5 parts by mass of wetting agent, and 0.1 to 5 parts by mass of defoamer to obtain a mixture; wherein , the molecular weight of the acrylate polymer in the acrylate emulsion is 200,000 to 2 million;

Apply the mixture on the surface of a plastic film layer, heat and cure at 70°C to 120°C for 2min to 10min, and then form a water-based acrylate film layer on the surface of the plastic film layer;

Pasting another plastic film layer on the other surface of the water-based acrylic adhesive film layer to prepare a vibrating film for a loudspeaker.

Preferably, the acrylate emulsion is obtained by adding 66 to 92 parts by mass of soft monomer, 8 to 33 parts by mass of hard monomer, 0.1 to 3 parts by mass to 40 to 100 parts by mass of deionized water It is prepared by reaction of 0.01-1 mass part of functional monomer, 0.01-1 mass part of initiator, 0.1-5 mass part of emulsifier, and 0.01-1.2 mass part of chain transfer agent.

Preferably, the acid value of the acrylate emulsion is 0 mgKOH/g to 40 mgKOH/g.

Preferably, the soft monomer is one or more of ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, and isooctyl acrylate.

Preferably, the hard monomer is one or more of acrylonitrile, acrylamide, styrene, methyl methacrylate, methyl acrylate, and vinyl acetate.

Preferably, the mass ratio of the soft monomer to the hard monomer is between 2:1 and 12:1.

Preferably, the functional monomer is one or more of methacrylic acid, acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, methacrylamide, N-methylolacrylamide, and glycidyl acrylate.

Further, in order to achieve the above object, the present application also provides a sound generating device, which includes a vibration system and a magnetic circuit system matched with the vibration system, and the vibration system includes a speaker diaphragm and a diaphragm combined with the speaker. The voice coil on one side of the membrane, the speaker diaphragm is the above-mentioned speaker diaphragm.

Further, in order to achieve the above purpose, the present application also provides a sound generating device, which includes a casing, a magnetic circuit system and a vibration system arranged in the casing, and the vibration system includes a voice coil, a first diaphragm and a second diaphragm, the top of the voice coil is connected to the first diaphragm, the magnetic circuit system drives the voice coil to vibrate to drive the first diaphragm to produce sound, and the two ends of the second diaphragm are respectively Connected with the casing and the bottom of the voice coil, the second diaphragm is the above-mentioned diaphragm for the speaker.

Embodiments of the present application provide a diaphragm for a speaker, a method for preparing a diaphragm for a speaker, and a sounding device. The diaphragm for a speaker includes a water-based acrylic film layer and two plastic film layers, and one of the two plastic film layers is The plastic film layer covers one surface of the water-based acrylic film layer, and the other plastic film layer covers the other surface of the water-based acrylic film layer; wherein the water-based acrylic film layer consists of Acrylate emulsion, curing agent, wetting agent, defoamer, the molecular weight of the acrylate polymer in the acrylate emulsion is between 200,000 and 2 million. The loudspeaker diaphragm prepared by the present application contains a water-based acrylic film layer. Because the glue forming the water-based acrylic film layer uses water as the medium, it is environmentally friendly and pollution-free. The compound has a higher molecular weight, which makes the prepared water-based acrylate film layer have higher resilience and high temperature resistance. Compared with the traditional solvent-based acrylate pressure-sensitive adhesive products, the water-based acrylate film layer prepared The high temperature resistance of the speaker diaphragm is better, which can improve the ability of the speaker in a high temperature environment, and thus can approach the development of the speaker towards high power.

Description of drawings

Fig. 1 is the schematic flow sheet of the loudspeaker diaphragm preparation method that the present application proposes;

Fig. 2 is the structure schematic diagram that the loudspeaker of the present application is a three-layer composite structure;

Fig. 3 is the structure schematic diagram that the loudspeaker of the present application is a five-layer composite structure;

Fig. 4 is the structural representation of the sounding device of the present application;

Fig. 5 is the frequency response curve figure in the product performance comparison process of the present application;

Fig. 6 is a graph of HOHD (high frequency harmonic distortion) in the performance comparison process of the products of the present application.

The realization, functional features and advantages of the present application will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

Detailed ways

It should be understood that the specific embodiments described here are only used to explain the present application, and are not intended to limit the present application.

Understandably, because the speaker industry considers product performance, listening, and cost, many products in the industry are using materials composed of plastic layers and damping rubber layers as speaker diaphragms. The plastic layer provides the stiffness required for the speaker diaphragm to vibrate, and the damping rubber layer provides the damping required for the speaker diaphragm to vibrate, and provides good adhesion to ensure the vibration consistency between the layers. Among them, the acrylate pressure-sensitive adhesive film is widely used because of its excellent adhesion, damping property, simple use process and low cost. However, the acrylate pressure-sensitive adhesive films currently used in the industry are all made of solvent-based acrylate glue through coating. The volatilization of a large amount of organic solvents during the coating process not only causes environmental pollution, but also poses a greater safety hazard. Secondly, the pressure-sensitive adhesive prepared by solvent-based acrylate glue is generally within 200,000 molecular weight of the acrylate polymer, and the prepared film material has insufficient high temperature resistance. With the increase of loudspeaker products' high power and large displacement requirements, the loudspeaker diaphragm needs to have good high temperature resistance.

Based on this, the present application proposes a diaphragm for a loudspeaker, the diaphragm for a loudspeaker comprises a water-based acrylic film layer and two plastic film layers, and one plastic film layer covers one surface of the water-based acrylic film layer in the two plastic film layers , another plastic film layer covers the other surface of the water-based acrylic film layer; wherein the water-based acrylic film layer can contain acrylate emulsion, curing agent, wetting agent, defoamer, acrylate polymerization in acrylate emulsion The molecular weight of the substance is between 200,000 and 2 million. For example, the molecular weight of the acrylate polymer in the acrylate emulsion can be 200,000, 250,000, 500,000, 600,000, 700,000, 850,000, 1 million, 1.5 million, 2 million etc.

Optionally, the thickness of the plastic film layer in this application can be 3um to 25um, for example, the thickness of the plastic film layer in this application can be 5um, 10um, 15um, 20um, 25um, etc. Optionally, the thickness of the water-based acrylate adhesive film layer in the present application may be 5um to 50um. For example, the thickness of the water-based acrylic film layer can be 5um, 10um, 15um, 20um, 25um, 30um, 35um, 40um, 45um, 50um, etc.

Optionally, the plastic film layer in this application can be made of polyetheretherketone (PEEK), polyarylate (PAR), polyetherimide (PEI), polyimide (PI), polyphenylene sulfide (PPS) ), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT).

It can be understood that the plastic film layer in the present application can be formed into a single-layer structure. When the plastic film layer is a single-layer structure, it can be made of one of the above materials, or two of the above materials can be used. compound of two or more species. Of course, the plastic film layer in this application can also be formed into a composite structure, that is, the plastic film layer can include multiple superimposed sub-film layers, and each sub-film layer can be made of any one of the above-mentioned materials.

Optionally, the above-mentioned curing agents include isocyanates, epoxy resins, amino resins, aziridines, etc., and the acrylate functional groups provide -OH/-COOH, etc. for functional monomers. These curing agents are characterized by having multiple The functional groups react with functional monomers to form a three-dimensional network structure. Optionally, the proportion of the curing agent in the water-based acrylic film layer is 0 parts by mass to 5 parts by mass, because, when the content of the curing agent in the water-based acrylic film layer is too little, the water-based acrylic adhesive The cohesion of the film layer is low. When the content of the curing agent is too much, the viscosity loss of the water-based acrylate film layer is large, and it is not easy to bond. When the proportion of the curing agent in the water-based acrylic film layer is between 0 parts by mass and 5 parts by mass, the cohesion of the water-based acrylic film layer can meet the needs of use, and the water-based acrylic film layer Moderate, easy to bond. For example, the proportion of curing agent in the water-based acrylic film layer can be 1 mass part, 2 mass parts, 3 mass parts, 4 mass parts and 5 mass parts. Preferably, the proportion of the curing agent in the water-based acrylate film layer may be 0.3 parts by mass to 1 part by mass. For example, the proportion of the curing agent in the water-based acrylate film layer can be 0.5 parts by mass, 0.7 parts by mass, 0.9 parts by mass, etc.

Optionally, the wetting agent may include: alkyl sulfates, sulfonates, fatty acid or fatty acid ester sulfates, carboxylic acid soaps, phosphoric acid esters, polyoxyethylene alkylphenol ethers, polyoxyethylene fatty alcohol ethers, Polyoxyethylene-propylene block copolymer, etc. The proportion of the wetting agent in the water-based acrylic film layer is 0.1 to 5 parts by mass. For example, the proportion of the wetting agent in the water-based acrylic film layer can be 0.1 parts by mass, 0.2 parts by mass, 1.5 parts by mass, 3 parts by mass, 5 parts by mass, etc., because when the wetting agent is in the water-based acrylic When the proportion of the ester film layer is too small, the wetting effect is not good. When coating some substrates with low surface tension, such as thermoplastic elastomers, natural rubber, silicone release paper, release film, etc., There will be shrinkage of the water-based acrylic film layer, causing coating shrinkage and other disadvantages; when the proportion of the wetting agent in the water-based acrylic film layer is too large, it will reduce the water-based acrylic film layer. Adhesive properties.

The antifoaming agent in this application is a substance that can reduce the surface tension of water, suspension, etc., prevent foam formation, or reduce or eliminate the original foam. Optionally, the defoamer can include alcohols, fatty acids and fatty acid esters, amides, phosphoric acid esters, phosphate triesters, organosilicon compounds, etc., and the proportion of the defoamer in the water-based acrylic film layer is 0.1 to 5 parts by mass. For example, the proportion of the defoamer in the water-based acrylate film layer can be 0.3 parts by mass, 0.5 parts by mass, 2 parts by mass, 4 parts by mass, 5 parts by mass, etc., because when the defoamer is too small, there will be bubbles , and when there is too much defoamer, there will be shrinkage, etc., which will affect the density of the water-based acrylic film layer.

It should be further noted that the monomers used to synthesize the above-mentioned acrylate emulsion in this application include soft monomers, hard monomers, and functional monomers; among them, the soft monomers have a relatively low glass transition temperature and are used to provide flexibility for the copolymer. Soft monomers include ethyl acrylate (EA), butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA), n-octyl acrylate, and isooctyl acrylate. Preferably, the soft monomer in this application is preferably butyl acrylate, and the amount added to the acrylate emulsion is 65 to 95 parts by mass. For example, the amount of butyl acrylate added to the acrylate emulsion can be 65 parts by mass, 75 parts by mass, 85 parts by mass, 95 parts by mass, etc.

The function of the hard monomer is to provide cohesion for the copolymer. Commonly used hard monomers include: acrylonitrile (AN), acrylamide (AM), styrene (St), methyl methacrylate (MMA), methyl acrylate ( MA), vinyl acetate (VAc), etc. In the present application, the preferred water resistance of the hard monomer is good, and the suitable monomer of the glass transition temperature is preferably one or more of styrene (St), methyl acrylate (MA), vinyl acetate (VAc) etc., which The mass fraction in the acrylate emulsion is 5 to 35 parts. For example, the mass fraction of the hard monomer in the acrylate emulsion can be 5 parts, 15 parts, 25 parts, 35 parts, etc.

Commonly used functional monomers include methacrylic acid (MAA), acrylic acid (AA), hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), methacrylamide (MAM), N-methylolacrylamide (NMA ), glycidyl acrylate, etc. The role of functional monomers is to provide crosslinkable points, methacrylic acid (MAA), acrylic acid (AA), hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), methacrylamide (MAM), N- Among methylolacrylamide (NMA) and glycidyl acrylate, methacrylic acid (MAA) and acrylic acid (AA) contain -COOH groups, which can not only provide reactive groups, but also improve the quality of water-based acrylate films to a certain extent. The adhesion of the layer is preferably methacrylic acid (MAA) and acrylic acid (AA) as the functional monomer of the water-based acrylate film layer, and the mass fraction of it in the acrylate emulsion is 0.5 to 3 parts. For example, the mass fraction of the functional monomer in the acrylate emulsion can be 0.5 parts, 1.5 parts, 2.5 parts, 3 parts, etc.

Further, the formula for calculating the glass transition temperature of the copolymer in the water-based acrylic film layer of the present application is as follows:

1/Tg＝W1/Tg1+W2/Tg2+...Wn/Tgn

Among them, Tg is the glass transition temperature of the copolymer; Tg1 is the glass transition temperature of the homopolymer of component 1, W1 is the mass fraction of component 1; Tg2 is the glass transition temperature of the homopolymer of component 2, and W2 is Parts by mass of component 2; Tgn is the glass transition temperature of the homopolymer of component n, and W2 is the parts by mass of component n.

Understandably, since the proportion of functional monomers in the acrylate emulsion is relatively small, ranging from 0.5 parts by mass to 3 parts by mass, the above formula can be estimated using only soft monomers and hard monomers. Due to the low temperature resistance and high temperature resistance requirements of the loudspeaker diaphragm material, the glass transition temperature of the water-based acrylic film layer is required to be about -20°C to -60°C, and the ratio of soft and hard monomers can be calculated by the formula. The ratio varies with the type of hard monomer used. Taking the preferred soft monomer as butyl acrylate and the hard monomer as styrene as an example, the ratio of soft monomer to hard monomer is 2:1 to 12:1. For example, the ratio of soft monomer to hard monomer can be 2:1, 3:1, 5:1, 7:1, 12:1 and so on.

It should be further noted that, in addition to soft monomers, hard monomers, and functional monomers, the materials for synthesizing acrylate emulsions also include initiators, emulsifiers, chain transfer agents, and deionized water; wherein, the initiators are water-soluble Hydrogen peroxide, potassium persulfate, ammonium persulfate, etc. that are thermally decomposed, the mass fraction of which in the acrylate emulsion is 0.01 to 1 part. For example, the mass fraction of the initiator in the acrylate emulsion can be 0.01 part, 0.03 part, 0.5 part, 1 part, etc. The main function is to provide free radicals. When the mass fraction of the initiator is too large, the reaction will be too fast, and the molecular weight of the polymer is too small. When the mass fraction of the initiator is too small, the reaction will be too slow. Therefore, the initiator in the acrylate emulsion The mass fraction is preferably 0.2 to 0.5 parts, for example, the mass fraction of the initiator in the acrylate emulsion is preferably 0.2, 0.3, 0.4, 0.5, etc.

Alternatively, chain transfer agents may include mercaptans, thioethers, carbon tetrachloride, and the like. The function of the chain transfer agent is to adjust the molecular weight of the polymer, and its proportion in the acrylate emulsion is 0.01 to 1.2 parts. For example, the proportion of the chain transfer agent in the acrylate emulsion can be 0.01 part, 0.1 part, 0.12 part, etc. Control the molecular weight of the acrylate polymer in the acrylate emulsion between 200,000 and 2 million, for example, the molecular weight of the acrylate polymer in the acrylate emulsion can be 200,000, 250,000, 500,000, 600,000, 700,000, 850,000 , 1 million, 1.5 million, 2 million, etc. Because when the molecular weight of the acrylate polymer in the acrylate emulsion is less than 200,000, the resilience of the acrylate film layer is poor after film formation, and the cohesion is low; and when the molecular weight is greater than 2 million, the adhesion of the acrylate film layer The strength becomes worse, and the molecular weight is preferably 600,000 to 1.2 million. For example, the molecular weight of the acrylate polymer in the acrylate emulsion can be preferably 600,000, 700,000, 850,000, 1 million, etc.; the proportion of chain transfer agent in the acrylate emulsion The parts by mass are preferably 0.1 to 0.5 parts by mass, for example, the parts by mass of the chain transfer agent in the acrylate emulsion can be preferably 0.1 parts by mass, 0.3 parts by mass, 0.5 parts by mass, etc.

Optionally, the emulsifier may include: an anionic emulsifier, such as sodium lauryl sulfate, sodium dodecylsulfonate, sodium alkylbenzenesulfonate, fatty acid, abietic acid, sodium salt of naphthenic acid, and the like. Nonionic emulsifiers include lauryl alcohol polyethylene oxide, propylene glycol polyethylene oxide, and polyethylene oxide sorbitol mono-mono fatty acid ester. The mass fraction of the emulsifier in the acrylate emulsion is 0.1 to 5 parts. For example, the mass fraction of the emulsifier in the acrylate emulsion can be 0.1 part, 0.5 part, 1 part, 3 parts, 5 parts, etc. Because when the content of emulsifier is too small, the emulsion will be unstable, and when the content of emulsifier is too much, the water resistance of the material will be deteriorated, so the mass fraction in the acrylate emulsion is preferably 0.5 to 2 parts. For example, the mass fraction of the emulsifier in the acrylate emulsion may preferably be 0.5 parts, 1 part, 1.2 parts, 2 parts, etc.

Deionized water is used as a solvent to adjust the solid content of the entire acrylic emulsion, and its mass fraction in the acrylic emulsion is 40 to 100 mass parts, such as the mass of deionized water in the acrylic emulsion The number of parts may be 40 parts by mass, 50 parts by mass, 60 parts by mass, 90 parts by mass, 100 parts by mass, or the like.

The peeling strength between the water-based acrylic film layer and the plastic film layer in the loudspeaker diaphragm of the present application is greater than or equal to 150g/25mm, because when the peeling force is less than 150g/25mm, the consistency of the loudspeaker diaphragm when vibrating is poor, and the product The sound quality deteriorates, and there is a risk of delamination or rupture of the speaker diaphragm after long-term vibration.

At the same time, by selecting hydrophobic soft monomers and hard monomers, the obtained water-based acrylic film layer has a lower acid value. The acid value of the film layer is 0mgKOH/g to 40mgKOH/g. For example, the acid value of the water-based acrylate film layer can be 10mgKOH/g, 20mgKOH/g, 30mgKOH/g, 40mgKOH/g. Preferably, the acid value of the water-based acrylate film layer is 1 to 30 mgKOH/g, because the higher the acid value, the stronger the hydrophilicity of the material, and the greater the performance change during application. For example, the acid value of the water-based acrylate film layer can be 1 mgKOH/g, 3 mgKOH/g, 5 mgKOH/g, 15 mgKOH/g, 25 mgKOH/g, etc.

In addition, during the actual use of the speaker, there will be a high-temperature and high-humidity environment. If the speaker diaphragm has poor heat and humidity resistance, after the speaker is used in a humid and hot environment for a long time, the strength of the water-based acrylic film layer will decrease. When the speaker diaphragm vibrates Problems such as adhesive layer failure and delamination will occur, so in this application, high temperature and high humidity (60°C-70°C, 90%-98% humidity) environment is used for 165h to 170h (preferably 65°C, 95% humidity environment for 168h) The change in T-peel strength between the final water-based acrylate adhesive film layer and the plastic film layer is less than or equal to 15%.

Further, the glass transition temperature of the water-based acrylate film layer is controlled by the ratio of the soft monomer and the hard monomer. From -20°C to -60°C, for example, the glass transition temperature of the water-based acrylate film layer can be -20°C, -30°C, -40°C, -60°C, etc. Because when the glass transition temperature is lower than -60°C, the water-based acrylate film layer is too soft, and its high temperature resistance is poor, and the glass transition temperature is higher than -20°C, the viscoelasticity of the water-based acrylate film layer decreases , When the speaker diaphragm vibrates, the toughness of the water-based acrylic film layer decreases, and the speaker diaphragm loses elasticity, resulting in poor sound quality.

Further, the storage modulus (at 150°C) of the water-based acrylate film layer in the present application is 0.01MPa to 1MPa, for example, the storage modulus (at 150°C) of the water-based acrylate film layer can be 0.02MPa . (at 150°C) can be preferably 0.02MPa, 0.06MPa, 0.09MPa, 0.1MPa, 0.3MPa, 0.6MPa, etc., because when the storage modulus of the water-based acrylate film layer is lower than 0.02MPa, the water-based acrylate adhesive The film layer is too soft, the cohesion is poor, and the molding is easy to pile up glue, resulting in poor molding. When the storage modulus of the water-based acrylic film layer is higher than 1MPa, the viscosity of the water-based acrylic film layer becomes poor, and it is easy to bond. Delamination defects occur.

Moreover, the holding force of the water-based acrylic film layer at 80°C*1h is less than or equal to 0.2mm, because the holding force test is that the water-based acrylic film layer is loaded at 80°C for 1 hour, and the water-based acrylic film It can be seen that the greater the sliding displacement, the lower the cohesive strength of the water-based acrylic film layer, and the worse the strength and temperature resistance of the material. Due to the phenomenon of inconsistent vibration displacement between the upper and lower film layers during the vibration process of the speaker diaphragm, resulting in relative movement, the cohesive strength or insufficient temperature resistance of the middle water-based acrylic film layer, the long-term After high-temperature vibration, the water-based acrylic film layer will be deformed to a certain extent, resulting in changes in product performance.

The loudspeaker diaphragm in the present application comprises a water-based acrylic film layer and two plastic film layers. The molecular weight of the acrylate polymer is between 200,000 and 2 million, which makes the prepared water-based acrylate film layer have higher resilience and high temperature resistance. Compared with traditional solvent-based acrylate pressure-sensitive adhesive products, The loudspeaker diaphragm prepared based on the water-based acrylate film layer has high temperature resistance.

The present invention also proposes a method for preparing a diaphragm for a loudspeaker. Referring to FIG. 1 , FIG. 1 is a schematic flowchart of a method for preparing a diaphragm for a loudspeaker proposed in this application.

The method for preparing a vibrating membrane for a loudspeaker includes the following steps:

Step S10, mixing 100 parts by mass of acrylate emulsion, 0 to 5 parts by mass of curing agent, 0.1 to 5 parts by mass of wetting agent, and 0.1 to 5 parts by mass of defoamer to obtain A mixture; wherein, the molecular weight of the acrylate polymer in the acrylate emulsion is 200,000 to 2 million;

In this step, it is first necessary to prepare the acrylate emulsion. Specifically, refer to Table 1. Table 1 is a list of raw material components, raw material names and parts by mass for preparing the acrylate emulsion in this application;

Table 1

According to the names of the raw materials in Table 1 and the corresponding mass parts, prepare the raw material components A, B, C, and D. First, add component D into the four-necked reaction flask. When the temperature is raised to 75°C under stirring, add the component Part C, after the temperature is stabilized at 75°C plus or minus 2°C, add components A and B dropwise at the same time, maintain an appropriate rate of addition so that the two components are added dropwise at the same time within about 3 hours, and then keep the temperature at 75°C for 1 hour and then cool down to The acrylate emulsion is prepared at about 40°C. It should be noted that nitrogen protection is required throughout this step.

It can be understood that the acrylate emulsion prepared through the above steps has poor heat resistance due to the linear structure of the polymer, and its wettability and defoaming properties are poor, so curing agents, defoamers, wetting agents, Thickeners and the like can be formulated into acrylate emulsion glue to meet the application. The proportioning ratio is shown in Table 2. Table 2 is the proportioning table of the acrylate emulsion glue required to form the water-based acrylate film layer in this application:

原料raw material	用量 Dosage

丙烯酸酯乳液Acrylic Emulsion	100100
固化剂Hardener	0-50-5
润湿剂lubricant	0.1-50.1-5
消泡剂Defoamer	0.1-50.1-5

Table 2

Specifically, according to 100 parts by mass, 0 parts by mass to 5 parts by mass, 0.1 parts by mass to 5 parts by mass, and 0.1 parts by mass to 5 parts by mass, the acrylate emulsion, curing agent, wetting agent, and defoamer were weighed in sequence, and then Mixing is effected and allowed to stand with stirring to form a mixture. More specifically, 0.1 to 3 parts by mass of a curing agent, 0.1 to 1 part by mass of a wetting agent, and 0.1 to 1 part by mass of an antifoaming agent can be sequentially added to the acrylate emulsion, and then use a mixer to /min to 800r/min and stir for 30 minutes or more, then let it stand for defoaming to form a mixture for use.

Step S20, coating the mixture on the surface of a plastic film layer, heating and curing at 70° C. to 120° C. for 2 minutes to 10 minutes, and forming a water-based acrylate film layer on the surface of the plastic film layer;

After standing to defoam in the above steps to form the mixture, the applicant can directly coat the uniformly mixed mixture on the surface of a plastic film layer, and pass through 70°C to 120°C (such as 70°C, 90°C, 100°C, 105 ℃, etc.) environment heating and curing for 2min to 10min, preferably 100℃ for 5min, so that the mixture is cured into a film, and a water-based acrylate film layer is formed on the surface of the plastic film layer to obtain a water-based acrylate film layer and a plastic film layer.

Step S30 , pasting another plastic film layer on the other surface of the water-based acrylic film layer to prepare a diaphragm for a loudspeaker.

It can be understood that the loudspeaker diaphragm in this application has a composite structure of at least three layers, so after forming a water-based acrylic adhesive film layer and a plastic film layer, another surface film layer needs to be applied to the water-based acrylic adhesive film layer. The other surface of the film layer is used to obtain the final speaker diaphragm.

It can be understood that there are at least two sets of preparation schemes for loudspeaker diaphragms in the present application, one of which is a double-sided release scheme: apply the mixed mixture glue to the release film 1 (that is, one of the two plastic film layers) plastic film layer), after heating and curing, the release film 2 (i.e. another plastic film layer in the two plastic film layers) is compounded on the other side of the water-based acrylic film layer to obtain a release film 1+water-based acrylic adhesive film + release film 2 (i.e. plastic film layer 1 + water-based acrylic film + plastic film layer 2), then use a compound machine to remove the release film, and combine the plastic film layer with the water-based acrylic film layer compound to form a composite diaphragm structure of plastic film layer + water-based acrylate film layer + plastic film layer, and this composite diaphragm structure is the final speaker diaphragm. The second is to directly coat the plastic film layer: directly apply the mixed mixture glue on one of the plastic film layers, and after heating and curing, compound the plastic film layer on the other side of the water-based acrylate film layer to form Speaker diaphragm with plastic film layer + water-based acrylic film layer + plastic film layer.

Referring to Fig. 2, Fig. 2 is a structural schematic diagram of a three-layer composite structure of the loudspeaker of the present application, wherein 1 and 3 are plastic film layers, and 2 is a water-based acrylic film layer. Further, after forming the water-based acrylic film layer and a plastic film layer, another plastic film layer 3 is pasted on the other surface of the water-based acrylic film layer 2 to form the water-based acrylic film layer 2 And both surface film layers are composite structures of plastic film layers (plastic film layer 1 and plastic film layer 3) (that is, the water-based acrylic film layer is the middle layer, and the two surface film layers are plastic film layers), so that the speaker vibration membrane. Moreover, the thickness and material of the plastic film layer can be the same or different, and the thickness is preferably 3um to 25um. For example, the thickness of the plastic film layer can be 3um, 5um, 10um, 15um, 25um, etc.; the thickness of the water-based acrylic film layer is 5um to 50um, for example, the thickness of the water-based acrylic film layer is 5um, 10um, 20um, 30um, 50um, etc. The composite material can be prepared by laminating a water-based acrylate film layer with two plastic layers, or by directly coating the water-based acrylate glue on the surface of a plastic film layer, heating and curing to form a film, and bonding with another plastic film layer. Prepared by laminating, the composite material can be hot-pressed and cut to obtain the required diaphragm for the loudspeaker.

It can be understood that the loudspeaker diaphragm in the present application is a composite structure of more than three layers, that is, in the present application, other material layers can be compounded on the surfaces of the two plastic film layers, and the other material layers can be plastic film layers, water-based acrylate glue, etc. Film layer, thermoplastic elastomer film layer, etc., specifically, one or more layers of other materials can be compounded on the surface of any plastic film layer, or other material layers can be compounded on the surface of two plastic film layers, wherein the compounded material layers and the number vary. The limit can be set according to actual needs. With reference to Fig. 3, Fig. 3 is the structural representation of the five-layer composite structure of the loudspeaker of the present application, wherein 1, 3 and 5 are plastic film layers, and 2 and 4 are water-based acrylic film layers, wherein the plastic film layers 1, 3, 5 The thickness and material can be the same or different, the preferred thickness is 3um to 15um, for example, the thickness of the plastic film layer can be 3um, 5um, 10um, 15um, etc.; the thickness of the water-based acrylic film layer 2,4 can be the same or different , the thickness is preferably 5um to 40um, for example, the thickness of the water-based acrylic film layer is 5um, 10um, 20um, 30um, 40um, etc. The composite material can be prepared by laminating the water-based acrylate film layer and the plastic film layer, or directly coating the water-based acrylate glue on the surface of a plastic film layer, heating and curing to form a film, and then bonding with another plastic film The composite material is prepared by laminating the surfaces of the layers, and the composite material is hot-pressed and cut to obtain the required loudspeaker diaphragm.

This application determines the glass transition temperature of the water-based acrylate film layer by controlling the ratio of soft and hard monomers, and determines the wettability of the water-based acrylate film layer. Generally speaking, the better the wettability, the higher the adhesion . At the same time, the amount of functional monomer and curing agent determine the amount of residual polarity -COOH of the functional monomer, which can regulate the peeling force of the water-based acrylic film layer, and the obtained water-based acrylic film layer has good adhesion. performance.

The loudspeaker diaphragm prepared by the present application contains a water-based acrylic film layer. Because the glue forming the water-based acrylic film layer uses water as the medium, it is environmentally friendly and pollution-free, and the production process is green and environmentally friendly. And the water-based acrylate film layer is prepared by adding an appropriate amount of curing agent, defoamer, wetting agent, etc. to the acrylate emulsion, and is prepared by coating and heating and curing. Molecular weight, the water-based acrylic film layer prepared by this method has higher resilience and high temperature resistance, compared with the traditional solvent-based acrylic pressure-sensitive adhesive products, the resistance of the product produced by the prepared loudspeaker diaphragm High temperature capability and anti-polarization capability are better, which in turn leads to better overall acoustic performance.

The present invention also proposes a sounding device, as shown in Figure 4, which is a structural schematic diagram of the sounding device of the present application; the sounding device includes a vibration system and a magnetic circuit system matched with the vibration system, and the vibration system includes The diaphragm for the speaker and the voice coil combined on one side of the diaphragm for the speaker, wherein the vibration system and the magnetic circuit system matched with the vibration system are used to make the sound generating device emit sound through vibration after being powered on. The coil is the coil through which the speaker passes current, and is an important part of the mechanical wave system of the electrodynamic speaker. It can be understood that those skilled in the art can make corresponding adjustments according to actual product requirements, such as the surround part protruding toward the voice coil side; the top of the ball is located on the lower surface of the surround part; centering struts are added to the vibration system, etc.; The loudspeaker diaphragm consists of a ring part and a ball top, and the loudspeaker diaphragm with a composite structure of a water-containing acrylic film layer and a plastic film layer can be located at the ring part, or at the ring part and the ball top.

The present invention also proposes a sounding device, the sounding device may include a housing and a magnetic circuit system and a vibration system arranged in the housing, the vibration system may include a voice coil, a first diaphragm and a second diaphragm, the top of the voice coil and the The first diaphragm is connected, the magnetic circuit system drives the voice coil to vibrate to drive the first diaphragm to produce sound, and the two ends of the second diaphragm are respectively connected to the shell and the bottom of the voice coil. Wherein, the second diaphragm may be the diaphragm for a loudspeaker according to the above-mentioned embodiments of the present invention.

That is to say, the first diaphragm can be used to vibrate and produce sound, and the second diaphragm can be used to balance the vibration of the voice coil. Specifically, when the sound generating device is working, the voice coil can vibrate up and down under the action of the magnetic field force of the magnetic circuit system after the voice coil is energized to drive the first diaphragm to vibrate, and the first diaphragm can vibrate to produce sound. The second diaphragm can also vibrate up and down with the voice coil. Since the two ends of the second diaphragm are respectively connected to the bottom of the shell and the voice coil, the second diaphragm can balance the vibration of the voice coil and prevent the polarization of the voice coil. Therefore, the sounding effect of the sounding device can be improved.

It should be noted that the first diaphragm and the second diaphragm can adopt the speaker diaphragm of the above-mentioned embodiment of the present invention at the same time, and one of the first diaphragm and the second diaphragm can adopt the above-mentioned diaphragm of the present invention. The loudspeaker diaphragm of the embodiment is not specifically limited in the present invention.

Further, the present application has also carried out a performance evaluation on the speaker diaphragm, and the evaluation content includes:

Glass transition temperature: tested by DSC equipment, the heating rate is 20 degrees Celsius/min, and the half-height method (ASTMD3418-15) is used to obtain the value;

Molecular weight: Tested by GPC, characterized by weight average molecular weight;

Peel strength: adopt GB/T2791-1995 standard, adopt T-peel method to test;

Holding force: Tested according to GB/T4851-2014 standard, after testing for 1 hour at a constant temperature of 80°C, test the sliding displacement of the water-based acrylic film layer;

Storage modulus@150°C (i.e. at 150°C): DMA equipment is used in tensile mode, the test frequency is 1Hz, the heating rate is 3°C/min, and the value method is the storage modulus value at 150°C;

Acid value: Tested according to GB/T17530.4-1998 standard.

Specifically, firstly, the preparation of acrylate emulsions with different formulation ratios is carried out: refer to Table 3, which is the preparation table of acrylate emulsions with different formulation ratios.

table 3

Prepare the raw material components A, B, C, and D according to the amounts in Table 3. First, add component D into the four-necked reaction flask. When the temperature rises to 75°C under stirring, add component C, and wait until the temperature is stabilized at 75°C. After ℃ plus or minus 2 ℃, add components A and B dropwise at the same time, maintain an appropriate rate of addition so that the two components are added dropwise at the same time within about 3 hours, and then keep at 75 ℃ for 1 hour and then cool down to about 40 ℃. Nitrogen protection.

The abbreviation of the monomer corresponds to:

Butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA),

Styrene (St), methyl methacrylate (MMA), methyl acrylate (MA),

Commonly used functional monomers include methacrylic acid (MAA), acrylic acid (AA).

Referring to Table 4, Table 4 is a performance comparison table of different acrylic emulsions:

方案号Scheme number	玻璃化温度(℃)Glass transition temperature (°C)	分子量molecular weight	酸值(mgKOH/g)Acid value (mgKOH/g)
实施例1Example 1	-43-43	100万1000000	88
实施例2Example 2	-57-57	93万930,000	88

实施例3Example 3	-43-43	42万420,000	88
实施例4Example 4	-20-20	90万900,000	88
实施例5Example 5	-30-30	88万880,000	4040

Table 4

Example 1, the soft monomer and hard monomer are BA and MA respectively, the ratio of soft monomer to hard monomer is 4:1, the glass transition temperature is -43°C, the molecular weight is 1 million, and the acid value is 8.

In Example 2, compared with Example 1, BA was replaced by 2-EHA in the soft monomer, the ratio of soft monomer and hard monomer was kept unchanged, and other conditions were unchanged. It can be seen that after 2-EHA is selected as the soft monomer, the glass transition temperature of the copolymer is reduced to -57°C, and the molecular weight is slightly reduced.

In Example 3, compared with Example 1, the types and ratios of soft monomers and hard monomers remain unchanged, the amount of chain transfer agent added is increased, and other conditions remain unchanged. Increasing the chain transfer agent can reduce the molecular weight of the copolymer, and the reduction of molecular weight will lead to the decrease of heat resistance and creep performance of the film.

Embodiment 4, compared with embodiment 1, change the ratio of soft monomer and the kind and the ratio of hard monomer, because the glass transition temperature of the homopolymer of MMA is higher, the glass transition temperature of gained copolymer increases to- At 20°C, the wettability decreases and the T-peel strength will decrease.

In Example 5, compared with Example 1, the acid value is controlled by controlling the amount of functional monomers added. If the acid value is large, the hydrophilicity of the obtained film is enhanced, and the water absorption rate of the material is high.

Based on the above results, the high molecular weight Example 1 was selected for the production and evaluation of the water-based acrylic film layer.

Secondly, the preparation of the water-based acrylic film layer is carried out, referring to Table 5, which is a table of water-based acrylic glues with different ratios:

table 5

Select the emulsion of Example 1 to configure different curing agents, wetting agents and acrylate glue formulations (as shown in Table 5), and coat it on the release film with a thickness of about 30um. At 90 to 110°C, Curing for 5 minutes to obtain the corresponding water-based acrylate film layer. The water-based acrylic film layer and the plastic film layer are compounded by a compound machine to form a diaphragm for a loudspeaker. Its performance is as shown in table 6, and embodiment and comparative example prepare the performance comparison table of waterborne acrylate film layer:

Table 6

Film performance comparison: The comparison example is the existing solvent-based acrylic film: use a solvent-based acrylic glue with a weight-average molecular weight of 200,000 and a glass transition temperature of -42°C, add curing agents, solvents, etc. for coating, curing, Make a double-sided release-type solvent-based acrylic, and then compound the solvent-based acrylic with a plastic film layer to become a speaker diaphragm material through a compounding device.

As mentioned above, since the molecular weight of the water-based acrylate copolymer is higher than that of conventional solvent-based acrylate copolymers, the storage modulus of the water-based acrylate film layer after curing is also higher, and the holding force displacement is smaller. Small, indicating that the water-based acrylate film layer of the present invention has higher cohesive strength and superior high temperature resistance.

In Example 1-1, the ratio of soft and hard monomers is 4:1, which determines the glass transition temperature is -43°C, the molecular weight of the copolymer is 1 million, the molecular weight is relatively high, and the high-temperature storage modulus is relatively high. The holding power is also higher, which is the preferred solution.

In Example 1-2, compared with Example 1-1, epoxy resin is used instead of toluene diisocyanate, different curing agents have different curing effects, prominent performance is peeling, and the strength varies.

Embodiment 1-3, compared with embodiment 1-1, replaces toluene diisocyanate with hexamethyl diisocyanate, the curing agent of embodiment 1-1 contains benzene ring, so its holding force is better than embodiment 1-3 .

In Example 1-4, compared with Example 1-1, the amount of toluene diisocyanate was added to 3 parts by mass. Due to the larger curing dose and higher degree of crosslinking, the T-peel strength decreased and the high temperature modulus increased. Increased stickiness.

Further, the present application also performs product performance comparison.

Specifically, the adhesive film of the water-based acrylic film layer of Example 1-1 with better performance and the conventional solvent-based acrylic film were selected for comparison, and were laminated and combined with polyether ether copper with a thickness of 9um. Laminated to obtain a material with a 3-layer composite structure. Then adopt the method of thermocompression forming, carry out the manufacture of diaphragm ring for loudspeaker, then cut according to product size, assemble into the loudspeaker unit, obtain the corresponding product, embodiment SPK and comparative example SPK. The acoustic performance test of the product under different voltages, the test results are as follows:

Referring to Fig. 5 and Fig. 6, Fig. 5 is a frequency response curve diagram during the product performance comparison process of the present application, and Fig. 6 is a HOHD (high frequency harmonic distortion) curve diagram during the product performance comparison process of the present application. Among them, the ordinate in Figure 5 is the sound pressure level, the unit is dB, the coordinate value starts from 50, and increases by 10, including 60, 70, 80, 90, 100, 110; the abscissa is the frequency, the unit is Hz, Its initial value is 100, and its incremental unit is 10 times the initial value, including 1000 and 10000; it also includes comparative example SPK-2.83V, embodiment SPK-2.83V, comparative example SPK-6V, and embodiment SPK The curve corresponding to -6V. In Figure 6, the ordinate is 100%, the unit is %, the initial value is 0, and the incremental unit is 5, which includes 0, 5, 10, 15, and the abscissa is frequency, the unit is Hz, and the initial value is 100, the incremental unit is 10 times the initial value, including 1000, 10000, which also includes the curves corresponding to Comparative Example SPK-2.83V, Example SPK-2.83V, Comparative Example SPK-6V, and Example SPK-6V .

Frequency Response Curve: The product has similar performance. As the test voltage increases, the sound pressure level of the product increases, that is, the loudness increases. This shows that as the test voltage increases, the displacement of the speaker's diaphragm vibration increases, thereby achieving an increase in loudness.

From the HOHD (High Frequency Harmonic Distortion) curve in Figure 6, it can be seen that with the increase of the test voltage, the SPK of the embodiment shows lower distortion, and the product noise is less. As the test voltage increases, the heat generated by the voice coil increases, and thus the high temperature resistance of the speaker diaphragm material is required to be higher. The water-based acrylate film layer has a higher molecular weight, higher cohesive energy between molecules, and the material has a stronger ability to resist deformation when the product vibrates, thus showing better acoustic performance.

It should be noted that, in this document, the term "comprising", "comprising" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, It also includes other elements not expressly listed, or elements inherent in the process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus comprising that element.

The serial numbers of the above embodiments of the present application are for description only, and do not represent the advantages and disadvantages of the embodiments.

The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structures or equivalent process transformations made by using the description of the application and the accompanying drawings are directly or indirectly used in other related technical fields. , are all included in the patent protection scope of the present application in the same way.

Claims

A loudspeaker diaphragm, characterized in that the loudspeaker diaphragm comprises a water-based acrylic film layer and two plastic film layers, and one of the plastic film layers covers the water-based acrylic film layer in the two plastic film layers. One surface of the adhesive film layer, another said plastic film layer is covered on the other surface of the said water-based acrylic ester adhesive film layer; The acrylate polymer in the acrylate emulsion has a molecular weight of 200,000 to 2 million.
The loudspeaker diaphragm according to claim 1, wherein the plastic film layer comprises polyetheretherketone, polyarylate, polyetherimide, polyimide, polyphenylene sulfide, polynaphthalene One or more of ethylene glycol formate, polyethylene terephthalate, polybutylene terephthalate.
The loudspeaker diaphragm according to claim 1, wherein the thickness of the water-based acrylic film layer is 5um to 50um.
The loudspeaker diaphragm according to claim 1, wherein the glass transition temperature of the water-based acrylic film layer is -20°C to -60°C.
The loudspeaker diaphragm according to claim 1, wherein the storage modulus of the water-based acrylic film layer at 150° C. is 0.01 MPa to 1 MPa.
The loudspeaker diaphragm according to claim 1, characterized in that, after the water-based acrylic film layer is treated in an environment of 60°C-70°C and 90% to 98% humidity for 165 hours to 170 hours, it is combined with the plastic The peel strength variation between film layers is less than 15%.
The loudspeaker diaphragm according to claim 1, wherein the peel strength between the plastic film layer and the water-based acrylic film layer is greater than or equal to 150g/25mm.
The loudspeaker diaphragm according to claim 1, wherein the holding force of the water-based acrylic film layer at 80°C*1h is less than or equal to 0.2mm.
A method for preparing a diaphragm for a loudspeaker, characterized in that the method for preparing a diaphragm for a loudspeaker comprises:

Mix 100 parts by mass of acrylate emulsion, 0 to 5 parts by mass of curing agent, 0.1 to 5 parts by mass of wetting agent, and 0.1 to 5 parts by mass of defoamer to obtain a mixture; wherein , the molecular weight of the acrylate polymer in the acrylate emulsion is 200,000 to 2 million;

Apply the mixture on the surface of a plastic film layer, heat and cure at 70°C to 120°C for 2min to 10min, and then form a water-based acrylate film layer on the surface of the plastic film layer;

Pasting another plastic film layer on the other surface of the water-based acrylic adhesive film layer to prepare a vibrating film for a loudspeaker.
The method for preparing a loudspeaker diaphragm according to claim 9, wherein the acrylate emulsion is obtained by adding 66 to 92 parts by mass of soft monomers, 8 parts by mass to 40 parts by mass to 100 parts by mass of deionized water. Parts by mass to 33 parts by mass of hard monomers, 0.1 to 3 parts by mass of functional monomers, 0.01 to 1 parts by mass of initiators, 0.1 to 5 parts by mass of emulsifiers, 0.01 to 1.2 parts by mass of Chain transfer agent reaction preparation.
The method for preparing a loudspeaker diaphragm according to claim 9, wherein the acid value of the acrylate emulsion is 0 mgKOH/g to 40 mgKOH/g.
The method for preparing a loudspeaker diaphragm as claimed in claim 10, wherein the soft monomer is ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate one or more of.
The method for preparing a loudspeaker diaphragm according to claim 10, wherein the hard monomer is one of acrylonitrile, acrylamide, styrene, methyl methacrylate, methyl acrylate, and vinyl acetate or more.
The method for preparing a loudspeaker diaphragm according to claim 10, wherein the mass ratio of the soft monomer to the hard monomer is between 2:1 and 12:1.
The method for preparing a loudspeaker diaphragm according to claim 10, wherein the functional monomer is methacrylic acid, acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, methacrylamide, N-methylol One or more of acrylamide and glycidyl acrylate.
A sounding device, characterized in that it includes a vibration system and a magnetic circuit system matched with the vibration system, the vibration system includes a speaker diaphragm and a voice coil combined on one side of the speaker diaphragm, the The speaker diaphragm is the speaker diaphragm according to any one of claims 1-8.
A sounding device, characterized in that it includes a housing and a magnetic circuit system and a vibration system arranged in the housing, the vibration system includes a voice coil, a first diaphragm and a second diaphragm, the voice coil The top is connected to the first diaphragm, the magnetic circuit system drives the voice coil to vibrate to drive the first diaphragm to produce sound, and the two ends of the second diaphragm are respectively connected to the housing and the sound The bottoms of the circles are connected, and the second diaphragm is the speaker diaphragm according to any one of claims 1-8.