Low-temperature-resistant acrylic diaphragm, preparation method and application thereof

Abstract

The present application relates to a kind of low temperature resistant acrylic vibrating diaphragm, and the preparation raw material of low temperature resistant acrylic vibrating diaphragm includes: 100 parts of functional ethylene acrylic ester rubber and process ethylene acrylic ester rubber, reinforcing agent 95~160 parts;Wherein, the mass of process ethylene acrylic ester rubber accounts for the proportion of the total mass of functional ethylene acrylic ester rubber and the process ethylene acrylic ester rubber is 1%~30%;Functional ethylene acrylic ester rubber is Vamac Ultra LT;Process ethylene acrylic ester rubber is selected from one or more of Vamac Ultra HVG, Vamac Ultra XF, Vamac Ultra IP, Vamac Ultra HT.The low temperature resistant acrylic vibrating diaphragm of the present application has good processing performance while having high low temperature resistance, and also has excellent high temperature resistance, can be used for long time under the condition of 180 DEG C.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of diaphragms, in particular to a low-temperature-resistant acrylic diaphragm and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of mobile phones, computers, new energy vehicles and smart wear, consumers have higher and higher requirements for the sound quality of electronic products. As the core component for realizing audio interaction, the performance of sound generating devices (such as loudspeakers) directly affects the user experience.

[0003] The diaphragm is a key component of the sound generating device. At present, there are composite diaphragms composed of multiple layers of materials such as PEEK (Polyether Ether Ketone), TPEE (Thermoplastic Polyester Elastomer), PEN (Polyethylene Naphthalate), and there are diaphragms composed of single acrylic rubber or silicone rubber material. For composite diaphragms, since they are composed of multiple layers of materials, the thickness of each layer of material has a tolerance, so the thickness tolerance of the composite diaphragm after the multiple layers of materials are compounded is larger, which will cause poor stability of the composite diaphragm, thereby making the distortion of the composite diaphragm larger. For rubber diaphragms of single material, although the problem of poor thickness stability of composite diaphragms is improved, the distortion performance of the diaphragm can be improved, but the current single material rubber diaphragm generally has poor low-temperature resistance (the resonant frequency F0 of the sound generating device is high below -25℃), and the processing difficulty is large.

[0004] Therefore, how to improve the low-temperature resistance of the diaphragm while considering its processing performance has become a technical problem to be solved at present. SUMMARY

[0005] Problems to be solved by the application

[0006] In view of the above problems existing in the prior art, the purpose of the present application is to provide a low-temperature-resistant acrylic diaphragm with high low-temperature resistance and good processing performance.

[0007] Solution for solving the problem

[0008] The present application provides a low-temperature-resistant acrylic diaphragm, the preparation raw materials of the low-temperature-resistant acrylic diaphragm include, by weight:

[0009] 100 parts of functional ethylene acrylate rubber and process ethylene acrylate rubber

[0010] 95-160 parts of reinforcing agent;

[0011] The ratio of the mass of the process ethylene acrylate rubber to the total mass of the functional ethylene acrylate rubber and the process ethylene acrylate rubber is 1% to 30%; the functional ethylene acrylate rubber is Vamac Ultra LT; and the process ethylene acrylate rubber is selected from one or more of Vamac Ultra HVG, Vamac Ultra XF, Vamac Ultra IP, and Vamac Ultra HT.

[0012] Preferably, the reinforcing agent is selected from one or more of talc, white carbon black, carbon black, quartz powder, calcium carbonate, and montmorillonite.

[0013] Preferably, the low-temperature-resistant acrylic vibrating diaphragm preparation raw material further includes one or more of an antioxidant, a vulcanizing agent, an accelerator, and a processing aid.

[0014] Preferably, the antioxidant is selected from one or more of an amine antioxidant, a phenolic antioxidant, and a quinoline antioxidant; and / or,

[0015] The vulcanizing agent is selected from an amine vulcanizing agent and / or a peroxide vulcanizing agent; and / or,

[0016] The accelerator is selected from one or more of an amine vulcanizing system accelerator, a peroxide vulcanizing system accelerator, and a sulfur vulcanizing system accelerator; and / or,

[0017] The processing aid is selected from one or more of a flow aid, a dispersing agent, a release agent, and a plasticizer.

[0018] Preferably, the low-temperature-resistant acrylic vibrating diaphragm preparation raw material includes, in parts by weight:

[0019] functional ethylene acrylate rubber and process ethylene acrylate rubber 100 parts

[0020] reinforcing agent 95 to 160 parts

[0021] antioxidant 0.1 to 8 parts

[0022] vulcanizing agent 0.1 to 5 parts

[0023] accelerator 0.1 to 8 parts

[0024] processing aid 1 to 10 parts.

[0025] Preferably, the low-temperature-resistant acrylic vibrating diaphragm preparation raw material includes, in parts by weight:

[0026] functional ethylene acrylate rubber 90 parts

[0027] process ethylene acrylate rubber 10 parts

[0028] Reinforcing agent 125 parts

[0029] Antioxidant 5 parts

[0030] Vulcanizing agent 1.5 parts

[0031] Accelerator 0.4 parts

[0032] Processing aid 9 parts;

[0033] Alternatively, the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm include, by weight parts:

[0034] Functional ethylene-acrylate rubber 99 parts

[0035] Process ethylene-acrylate rubber 1 part

[0036] Reinforcing agent 125 parts

[0037] Antioxidant 5 parts

[0038] Vulcanizing agent 1.5 parts

[0039] Accelerator 0.4 parts

[0040] Processing aid 9 parts;

[0041] Alternatively, the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm include, by weight parts:

[0042] Functional ethylene-acrylate rubber 80 parts

[0043] Process ethylene-acrylate rubber 20 parts

[0044] Reinforcing agent 125 parts

[0045] Antioxidant 5 parts

[0046] Vulcanizing agent 1.5 parts

[0047] Accelerator 0.4 parts

[0048] Processing aid 9 parts;

[0049] Alternatively, the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm include, by weight parts:

[0050] Functional ethylene-acrylate rubber 70 parts

[0051] Process ethylene-acrylate rubber 30 parts

[0052] Reinforcing agent 125 parts

[0053] Antioxidant 5 parts

[0054] Vulcanizing agent 1.5 parts

[0055] Promoter 0.4 parts

[0056] Processing aid 9 parts.

[0057] The application further provides a preparation method of the low-temperature-resistant acrylic vibrating diaphragm, and the method comprises the following steps:

[0058] S1: mixing the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm, and performing banbury processing to obtain a rubber compound;

[0059] S2: preparing the rubber compound into a rubber compound film piece;

[0060] S3: preparing the rubber compound film piece into the low-temperature-resistant acrylic vibrating diaphragm by using air pressure forming.

[0061] Preferably, the method for preparing the rubber compound film piece in step S2 comprises calendering or solution coating.

[0062] The thickness of the rubber compound film piece is 20 μm to 200 μm.

[0063] Preferably, in step S3, the temperature of the air pressure forming is 180 ℃ to 200 ℃, the pressure of the air pressure forming is 0.2 Mpa to 2 Mpa, and the time of the air pressure forming is 40 s to 150 s.

[0064] The application further provides application of the low-temperature-resistant acrylic vibrating diaphragm or the preparation method in the field of sound generating devices.

[0065] Effects of the application

[0066] The application provides a low-temperature-resistant acrylic vibrating diaphragm for a sound generating device, which is prepared by reasonably matching and combining functional ethylene acrylate rubber with excellent low-temperature resistance, process ethylene acrylate rubber with excellent processing performance and a reinforcing agent, so that the low-temperature-resistant acrylic vibrating diaphragm has high low-temperature resistance and good processing performance. In addition, the low-temperature-resistant acrylic vibrating diaphragm contains only single ethylene acrylate rubber (AEM), and has excellent high-temperature resistance compared with a rubber vibrating diaphragm containing a mixed material of AEM and acrylate rubber (ACM), and can be used for a long time at 180 ℃. DETAILED DESCRIPTION

[0067] In order to make the technical solutions and beneficial effects of the application more obvious and easy to understand, the following will be described in detail by means of specific embodiments. Unless otherwise defined, the technical and scientific terms used herein have the same meaning as the technical and scientific terms in the technical field to which the application belongs.

[0068] The equipment and raw materials used in the application can be purchased in the market, including but not limited to the following raw materials:

[0069] Vamac® Ultra LT, AEM gum, DuPont, USA.

[0070] Vamac® Ultra XF, AEM gum, DuPont, USA.

[0071] AR72LS, ACM rubber, Tg point -28℃, Mooney viscosity 33MU, Japan Zeon.

[0072] HYT-05C, talc, Suzhou Youmin Plastic New Material Co., Ltd.

[0073] Omya Carb ST, calcium carbonate Omya Carb ST (UF / AL), Switzerland Omya.

[0074] VN3, white carbon black, Evonik.

[0075] Antioxidant 246, Flectol TMQ, Akzo Nobel.

[0076] HMDC, hexamethylene diamine carbamate, vulcanizing agent, DuPont, USA Diak No. 1.

[0077] ACT55, guanidine / amine complex derivative, accelerator, France Safic Alkene.

[0078] Licowax PE520, polyethylene wax, Clariant.

[0079] Struktol A50P, fatty acid ester processing aid, Struktol Company.

[0080] TP-95, polyester plasticizer, USA Rohm & Haas.

[0081] As used herein, the term "glass transition temperature" or "Tg" refers to the temperature corresponding to the transition from glassy to high-elastic state, which is an inherent property of amorphous polymer materials and a macroscopic manifestation of the transition of the form of polymer movement. The glass transition temperature (Tg) is the lowest temperature at which the molecular chain segment can move, and its level is directly related to the flexibility of the molecular chain. The greater the flexibility of the molecular chain, the lower the glass transition temperature; the greater the rigidity of the molecular chain, the higher the glass transition temperature. As used herein, the method for measuring the glass transition temperature includes weighing 10 mg of rubber sample, using a DSC differential scanning calorimeter (Netzsch DSC 200F3, Germany) for testing, with a temperature rise rate of 10 K / min.

[0082] As used herein, the term "Mooney viscosity" is an important indicator for characterizing the rheological properties of unvulcanized rubber (gum or mixed rubber), which is used to measure the viscosity (i.e., flowability or processing performance) of rubber at a specific temperature and shear rate.

[0083] Ethylene acrylate rubber (AEM) has good high temperature resistance and is widely used in the field of diaphragm. However, it is difficult to make the low temperature resistance of AEM rubber low, and currently only one kind of rubber with a glass transition temperature Tg lower than -30℃, namely Vamac Ultra LT (Tg=-41℃) of DuPont, has a low Mooney viscosity, poor processing performance, and often appears to be bonded to the grinding tool, which is difficult to demould, so that the shape of the diaphragm is damaged, thereby directly affecting the performance of the diaphragm.

[0084] Based on this, the application provides a low-temperature-resistant acrylic diaphragm, and the preparation raw materials of the low-temperature-resistant acrylic diaphragm include, by weight:

[0085] 100 parts of functional ethylene acrylate rubber and processable ethylene acrylate rubber

[0086] 95-160 parts of reinforcing agent

[0087] The mass of the processable ethylene acrylate rubber accounts for 1%-30% of the total mass of the functional ethylene acrylate rubber and the processable ethylene acrylate rubber; the functional ethylene acrylate rubber is Vamac Ultra LT; and the processable ethylene acrylate rubber is selected from one or more of Vamac Ultra HVG, Vamac Ultra XF, Vamac Ultra IP and Vamac Ultra HT.

[0088] The functional ethylene acrylate rubber in the application can be referred to as functional AEM, which refers to AEM raw rubber with high low-temperature resistance. The processable ethylene acrylate rubber can be referred to as processable AEM, which refers to AEM raw rubber that is easy to disperse and process and can improve the mixing and forming process of the diaphragm. The glass transition temperature of the functional ethylene acrylate rubber is less than or equal to -40℃, and the Mooney viscosity of the functional ethylene acrylate rubber is less than 15 MU; the glass transition temperature of the processable ethylene acrylate rubber is greater than -40℃ and less than or equal to -30℃, and the Mooney viscosity of the processable ethylene acrylate rubber is greater than 20 MU. Through reasonable matching and combination of the functional AEM with excellent low-temperature resistance, the processable AEM with excellent processing performance and the reinforcing agent, the low-temperature-resistant acrylic diaphragm has high low-temperature resistance and good processing performance, that is, the low-temperature-resistant acrylic diaphragm is easy to process. In addition, the low-temperature-resistant acrylic diaphragm includes only ethylene acrylate rubber (AEM), and has excellent high-temperature resistance compared with the rubber diaphragm including a mixed material of AEM and acrylate rubber (ACM), and can be used for a long time at 180℃.

[0089] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra HVG, Vamac® Ultra XF, Vamac® Ultra IP, and Vamac® Ultra HT.

[0090] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra HVG, Vamac® Ultra XF, and Vamac® Ultra IP.

[0091] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra HVG, Vamac® Ultra XF, and Vamac® Ultra HT.

[0092] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra HVG, Vamac® Ultra IP, and Vamac® Ultra HT.

[0093] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra XF, Vamac® Ultra IP, and Vamac® Ultra HT.

[0094] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra HVG, and Vamac® Ultra XF.

[0095] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra HVG, and Vamac® Ultra IP.

[0096] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra HVG, and Vamac® Ultra HT.

[0097] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra XF, and Vamac® Ultra IP.

[0098] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra XF, and Vamac® Ultra HT.

[0099] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra IP, and Vamac® Ultra HT.

[0100] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra HVG.

[0101] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra XF.

[0102] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra IP.

[0103] In certain embodiments, the processable ethylene propylene acrylate rubber is Vamac® Ultra HT.

[0104] In certain embodiments, the ratio of the mass of the processable ethylene propylene acrylate rubber to the total mass of the functional ethylene propylene acrylate rubber and the processable ethylene propylene acrylate rubber is 1%, 5%, 10%, 15%, 20%, 25%, 30% or any value between any two of the aforementioned values.

[0105] In certain embodiments, the reinforcing agent is selected from one or more of talc, white carbon, carbon black, quartz powder, calcium carbonate, montmorillonite.

[0106] In certain embodiments, the reinforcing agent is selected from one or more of carbon black N330, medium particle carbon black N550, precipitated white carbon Zeosil 1165MP, precipitated white carbon VN3, calcium carbonate Omya Carb ST, talc HYT-55X, talc HYT-05C, aluminum hydroxide Martinal OL-104.

[0107] In certain embodiments, the reinforcing agent is selected from one or more of precipitated white carbon VN3, calcium carbonate Omya Carb ST, talc HYT-05C.

[0108] In certain embodiments, the reinforcing agent is precipitated white carbon VN3, calcium carbonate Omya Carb ST, and talc HYT-05C.

[0109] In certain embodiments, the reinforcing agent is precipitated white carbon VN3 and calcium carbonate Omya Carb ST.

[0110] In certain embodiments, the reinforcing agent is precipitated white carbon VN3 and talc HYT-05C.

[0111] In certain embodiments, the reinforcing agent is calcium carbonate Omya Carb ST and talc HYT-05C.

[0112] In certain embodiments, the reinforcing agent is precipitated white carbon VN3.

[0113] In certain embodiments, the reinforcing agent is calcium carbonate Omya Carb ST.

[0114] In certain embodiments, the reinforcing agent is talc HYT-05C.

[0115] In certain embodiments, the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm include, in parts by weight, 95 parts, 100 parts, 105 parts, 110 parts, 115 parts, 120 parts, 125 parts, 130 parts, 135 parts, 140 parts, 145 parts, 150 parts, 155 parts, 160 parts, or any value within a range between any two of the above values, of the reinforcing agent.

[0116] In certain embodiments, the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm further include one or more of an antioxidant, a vulcanizing agent, an accelerator, and a processing aid.

[0117] In certain embodiments, the antioxidant is selected from one or more of an amine antioxidant, a phenolic antioxidant, and a quinoline antioxidant.

[0118] In certain embodiments, the antioxidant is selected from one or more of 6PPD (N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine), IPPD (N-isopropyl-N'-phenyl-p-phenylenediamine), antioxidant 445 (4,4'-di(α,α-dimethylbenzyl)diphenylamine), antioxidant BLE (acetone-diphenylamine condensate), BHT (2,6-di-tert-butyl-p-cresol), antioxidant 246 (TMQ polymer).

[0119] In certain embodiments, the antioxidant is antioxidant 246.

[0120] In certain embodiments, the vulcanizing agent is selected from an amine vulcanizing agent and / or a peroxide vulcanizing agent.

[0121] In certain embodiments, the vulcanizing agent is selected from one or more of hexamethylenediamine carbamate, hexamethylenediamine carbamate, N,N'-dicinnamaldehyde condensate, dicumyl peroxide, bis-2,5 (2,5-dimethyl-2,5 bis-tert-butyl peroxy) hexane.

[0122] In certain embodiments, the vulcanizing agent is hexamethylenediamine carbamate.

[0123] In certain embodiments, the accelerator is selected from one or more of an amine vulcanizing system accelerator, a peroxide vulcanizing system accelerator, and a sulfur vulcanizing system accelerator.

[0124] In certain embodiments, the accelerator is selected from one or more of guanidine / amine complex derivatives, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), tetramethylguanidine (TMG), magnesium oxide (MgO), triallyl isocyanurate (TAIC).

[0125] In certain embodiments, the accelerator is guanidine / amine complex derivatives ACT55.

[0126] In certain embodiments, the processing aid is selected from one or more of flow aids, dispersants, release agents, plasticizers.

[0127] In certain embodiments, the processing aid is selected from one or more of stearic acid, zinc stearate, polyethylene wax (PE wax), fatty acid G-78, fatty acid ester Struktol A50P, organosilicon Dow Corning MB50-001, polyester plasticizer TP-95.

[0128] In certain embodiments, the processing aid is Licowax PE520, fatty acid ester Struktol A50P, and polyester plasticizer TP-95.

[0129] In certain embodiments, the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm include, in parts by weight:

[0130] functional ethylene-acrylic ester rubber and process ethylene-acrylic ester rubber 100 parts

[0131] reinforcing agent 95-160 parts

[0132] antioxidant 0.1-8 parts

[0133] vulcanizing agent 0.1-5 parts

[0134] accelerator 0.1-8 parts

[0135] processing aid 1-10 parts.

[0136] In certain embodiments, the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm include, in parts by weight, a reinforcing agent 95 parts, 100 parts, 105 parts, 110 parts, 115 parts, 120 parts, 125 parts, 130 parts, 135 parts, 140 parts, 145 parts, 150 parts, 155 parts, 160 parts, or any value between any two of the aforementioned values.

[0137] In certain embodiments, the low temperature resistant acrylic vibrating diaphragm is prepared from raw materials including an antioxidant in an amount of 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, or any value between any two of the aforementioned values.

[0138] In certain embodiments, the low temperature resistant acrylic vibrating diaphragm is prepared from raw materials including a vulcanizing agent in an amount of 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, or any value between any two of the aforementioned values.

[0139] In certain embodiments, the low temperature resistant acrylic vibrating diaphragm is prepared from raw materials including a vulcanizing agent in an amount of 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, or any value between any two of the aforementioned values.

[0140] In certain embodiments, the low temperature resistant acrylic vibrating diaphragm is prepared from raw materials including a processing aid in an amount of 1 parts by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, or any value between any two of the aforementioned values.

[0141] In certain embodiments, the low temperature resistant acrylic vibrating diaphragm is prepared from raw materials including:

[0142] functional ethylene acrylic ester rubber 90 parts

[0143] process ethylene acrylic ester rubber 10 parts

[0144] reinforcing agent 125 parts

[0145] antioxidant 5 parts

[0146] vulcanizing agent 1.5 parts

[0147] accelerating agent 0.4 parts

[0148] processing aid 9 parts.

[0149] In certain embodiments, the low temperature resistant acrylic vibrating diaphragm is prepared from raw materials including:

[0150] functional ethylene acrylic ester rubber 99 parts

[0151] process ethylene acrylic ester rubber 1 part

[0152] reinforcing agent 125 parts

[0153] antioxidant 5 parts

[0154] Vulcanizing agent 1.5 parts

[0155] Accelerator 0.4 parts

[0156] Processing aid 9 parts.

[0157] In some embodiments, the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm include, by weight parts:

[0158] Functional ethylene acrylic ester rubber 80 parts

[0159] Processable ethylene acrylic ester rubber 20 parts

[0160] Reinforcing agent 125 parts

[0161] Antioxidant 5 parts

[0162] Vulcanizing agent 1.5 parts

[0163] Accelerator 0.4 parts

[0164] Processing aid 9 parts.

[0165] In some embodiments, the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm include, by weight parts:

[0166] Functional ethylene acrylic ester rubber 70 parts

[0167] Processable ethylene acrylic ester rubber 30 parts

[0168] Reinforcing agent 125 parts

[0169] Antioxidant 5 parts

[0170] Vulcanizing agent 1.5 parts

[0171] Accelerator 0.4 parts

[0172] Processing aid 9 parts.

[0173] In some embodiments, the low-temperature-resistant acrylic vibrating diaphragm has a glass transition temperature Tg of -60℃ to -40℃. The glass transition temperature enables the low-temperature-resistant acrylic vibrating diaphragm to have high low-temperature resistance, and the vibrating diaphragm can still work normally at a low temperature and maintain good acoustic performance.

[0174] The application also provides a preparation method of the low-temperature-resistant acrylic vibrating diaphragm described in the above embodiments, and the method comprises the following steps:

[0175] S1: mixing the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm described in the above embodiments, and performing banbury processing to obtain a rubber compound;

[0176] S2: preparing the rubber compound into a rubber compound film piece;

[0177] S3: preparing the rubber compound film piece into the low-temperature-resistant acrylic vibrating diaphragm by air pressure forming.

[0178] In some embodiments, the internal mixing process in step S1 is to mix the raw materials for preparing the low-temperature-resistant acrylic vibrating diaphragm into a rubber compound by using an internal mixer.

[0179] In some embodiments, the way of preparing the rubber compound film piece in step S2 includes calendering into a film or solution coating into a film.

[0180] In some embodiments, the preparation of the rubber compound into a rubber compound film piece by solution coating into a film can include: first, dissolving the rubber compound into a specific solvent by dissolution, where the dissolution is physical dissolution, i.e. the solvent cannot react with the components in the rubber compound, so as to avoid affecting the performance of the prepared vibrating diaphragm, especially avoiding affecting the color of the prepared vibrating diaphragm. The solvent can be, for example, ethyl acetate and / or butyl acetate; then, coating and drying the above dissolved rubber compound by using a coating machine to obtain a rubber compound film piece.

[0181] In some embodiments, the thickness of the rubber compound film piece is 20 μm to 200 μm.

[0182] In some embodiments, in step S3, the temperature of the air pressure forming is 180°C to 200°C; the pressure of the air pressure forming is 0.2 Mpa to 2 Mpa; and the time of the air pressure forming is 40 s to 150 s.

[0183] The application also provides an application of the low-temperature-resistant acrylic vibrating diaphragm or the preparation method in the field of sound generating devices.

[0184] In some embodiments, the application includes being used as a vibrating diaphragm in a sound generating device, specifically, for example, a loudspeaker.

[0185] The technical solutions of the application will be further described below in combination with multiple embodiments and multiple comparative examples.

[0186] Embodiment 1: Preparation of a vibrating diaphragm

[0187] Step 1: mixing the raw materials into a rubber compound by using an internal mixer, and the specific raw materials and the ratio (by weight) are shown in Table 1;

[0188] Step 2: preparing the rubber compound into a rubber compound film piece;

[0189] Step 3: preparing the rubber compound film piece into a vibrating diaphragm by air pressure forming.

[0190] Example 2-Example 4: Preparation of the diaphragm

[0191] The preparation method is shown in Example 1, and the specific raw materials and the ratio (by weight) are shown in Table 1.

[0192] Comparative Example 1-Comparative Example 6: Preparation of the diaphragm

[0193] The preparation method is shown in Example 1, and the specific raw materials and the ratio (by weight) are shown in Table 1.

[0194] Table 1: Raw materials and ratios of the diaphragm in Example 1-Example 4 and Comparative Example 1-Comparative Example 6

[0195]

[0196] The diaphragms prepared in Example 1-Example 4 and Comparative Example 1-Comparative Example 6 were tested for performance, and the test results are shown in Table 2.

[0197] (1) Demolding performance test: The demolding performance refers to the 90 μm rubber mold using air pressure forming method, and the forming tool is a one-mold two-out copper tool. The forming process is 190℃, 0.5Mpa, 90s. The demolding condition is divided into three categories: o represents easy demolding, and the forming appearance is good; Δ represents difficult demolding, and the forming has defects; × represents very difficult demolding or even cannot demolding, and the diaphragm is lost or broken. In addition, "+" means slightly better, and "-" means slightly worse.

[0198] (2) Elongation at break and tensile strength test according to ASTM D412-2016 standard.

[0199] (3) Tensile strength retention rate refers to:

[0200] Tensile strength retention rate = (tensile strength after aging / tensile strength before aging) x 100%.

[0201] (4) Glass transition temperature Tg point is tested by DSC differential scanning calorimeter, and the heating rate is 10K / min.

[0202] (5) Rubber compression set refers to ASTM D395, and the test conditions are 23℃ environment, 24h placement, and compression rate is 25%. Compression set (%) = ((t0-t1) / (t0-t s )) x 100; wherein t0 is the original thickness of the sample, t1 is the thickness after recovery of the sample, and t s is the thickness of the limiter (gap under compression).

[0203] Table 2: Performance of the diaphragm prepared in Example 1-Example 4 and Comparative Example 1-Comparative Example 6

[0204]

[0205] From the performance test results of Comparative Examples 1-3, it can be seen that, regardless of the reinforcing agent used, the processing performance of the diaphragm prepared is poor when the mass fraction of the added reinforcing agent is 90 parts, and it is difficult to demold, among which talc performs best and white carbon black performs worst.

[0206] From the performance test results of Comparative Examples 4 and 5, it can be seen that the processing performance of the diaphragm prepared can be improved by increasing the added fraction of the reinforcing agent and the addition process AEM, but the improvement effect is not obvious, and it is still difficult to demold during preparation.

[0207] From the performance test results of Comparative Example 6, it can be seen that the diaphragm prepared containing functional AEM and ACM rubber has an elongation at break and a breaking strength retention rate after aging at 180℃ for 7 days both of which are lower than 50%, belonging to a failure state, and the main reason is that the long-term temperature resistance of ACM rubber is about 30℃ lower than that of AEM.

[0208] From the performance test results of Examples 1-4, it can be seen that, while adding process AEM, increasing the added fraction of the reinforcing agent can significantly improve the processing performance of the low-temperature-resistant acrylic diaphragm prepared, which is easy to demold during preparation and has a good molding appearance. Moreover, the low-temperature-resistant acrylic diaphragm prepared in Examples 1-4 has a high level of elongation at break and breaking strength after aging at 180℃ for 7 days, and a low compression set, that is, the pure AEM rubber diaphragm prepared in the present application has good comprehensive performance of Tg≤-40℃, good low-temperature resistance and high-temperature resistance up to 180℃ while improving the processing performance of the low-temperature-resistant acrylic diaphragm.

[0209] In the present application, the proportion of process AEM cannot be too high, which can easily affect the low-temperature resistance of the low-temperature-resistant acrylic diaphragm prepared, and the proportion of process AEM cannot be too low, which cannot effectively improve the processing difficulty of the diaphragm prepared. By increasing the mass fraction of the reinforcing agent to 95-160 parts and combining with process AEM rubber with good processability in a suitable proportion, the process of functional AEM (Ultra LT) for making diaphragm and the stiffness of the diaphragm are improved, the diaphragm process window is wide, and it is easy to demold, avoiding the performance reduction problem caused by a large amount of demolding agent in the existing formula. The low-temperature-resistant acrylic diaphragm prepared in the present application is easy to process, and at the same time, the low-temperature-resistant acrylic diaphragm has excellent high-temperature resistance (180℃).

[0210] It should be understood that the above examples are exemplary and are not intended to be limiting in terms of all possible implementations. Various modifications and changes can be made thereto without departing from the scope of the present disclosure, which is set forth in the following claims. Similarly, each of the individual features of the above examples can be applied to an arbitrary combination, to form further embodiments of the present application which have not been explicitly described. Therefore, the above examples merely express several embodiments of the present application, and do not limit the scope of protection of the patent of the present application.

Claims

1. A low temperature resistant acrylic diaphragm, characterized by, The preparation raw materials of the low-temperature-resistant acrylic vibrating diaphragm include, in parts by weight: 100 parts in total of functional ethylene acrylic ester rubber and process ethylene acrylic ester rubber 95-160 parts of reinforcing agent The mass of the process ethylene acrylic ester rubber accounts for 1-30% of the total mass of the functional ethylene acrylic ester rubber and the process ethylene acrylic ester rubber; the functional ethylene acrylic ester rubber is Vamac Ultra LT; the process ethylene acrylic ester rubber is selected from one or more of Vamac Ultra HVG, Vamac Ultra XF, Vamac Ultra IP, and Vamac Ultra HT; The reinforcing agent is selected from one or more of talc, white carbon black, carbon black, quartz powder, calcium carbonate, and montmorillonite.

2. The low temperature resistant acrylic diaphragm of claim 1, wherein, The preparation raw materials of the low-temperature-resistant acrylic vibrating diaphragm further include one or more of antioxidant, vulcanizing agent, accelerator, and processing aid.

3. The low-temperature-resistant acrylic vibrating diaphragm according to claim 2, characterized in that The antioxidant is selected from one or more of amine antioxidant, phenolic antioxidant, and quinoline antioxidant; and / or The vulcanizing agent is selected from amine vulcanizing agent and / or peroxide vulcanizing agent; and / or The accelerator is selected from one or more of amine vulcanizing system accelerator, peroxide vulcanizing system accelerator, and sulfur vulcanizing system accelerator; and / or The processing aid is selected from one or more of flow aid, dispersant, release agent, and plasticizer.

4. The low temperature resistant acrylic diaphragm of claim 2, wherein, The preparation raw materials of the low-temperature-resistant acrylic vibrating diaphragm include, in parts by weight: 100 parts in total of functional ethylene acrylic ester rubber and process ethylene acrylic ester rubber 95-160 parts of reinforcing agent 0.1-8 parts of antioxidant 0.1-5 parts of vulcanizing agent 0.1-8 parts of accelerator 1-10 parts of processing aid.

5. The low temperature resistant acrylic diaphragm of claim 4, wherein, The preparation raw materials of the low-temperature-resistant acrylic vibrating diaphragm include, in parts by weight: 90 parts of functional ethylene acrylic ester rubber 10 parts of process ethylene acrylic ester rubber 125 parts of reinforcing agent 5 parts of antioxidant 1.5 parts of vulcanizing agent 0.4 parts of accelerator 9 parts of processing aid. Alternatively, the preparation raw materials of the low-temperature-resistant acrylic vibrating diaphragm include, in parts by weight: 99 parts of functional ethylene acrylic ester rubber 1 part of process ethylene acrylic ester rubber 125 parts of reinforcing agent 5 parts of antioxidant 1.5 parts of vulcanizing agent 0.4 parts of accelerator 9 parts of processing aid. Alternatively, the preparation raw materials of the low-temperature-resistant acrylic vibrating diaphragm include, in parts by weight: 80 parts of functional ethylene acrylic ester rubber 20 parts of process ethylene acrylic ester rubber 125 parts of reinforcing agent 5 parts of antioxidant 1.5 parts of vulcanizing agent 0.4 parts of accelerator 9 parts of processing aid. Alternatively, the preparation raw materials of the low-temperature-resistant acrylic vibrating diaphragm include, in parts by weight: 70 parts of functional ethylene acrylic ester rubber 30 parts of process ethylene acrylic ester rubber 125 parts of reinforcing agent 5 parts of antioxidant 1.5 parts of vulcanizing agent 0.4 parts of accelerator 9 parts of processing aid.

6. A method of producing a low-temperature-resistant acrylic diaphragm according to any one of claims 1 to 5, characterized by, The method includes the following steps: S1: mixing the preparation raw materials of the low-temperature-resistant acrylic vibrating diaphragm according to any one of claims 1-5, and then performing banbury processing to obtain a mixed rubber; S2: preparing the rubber compound into a rubber compound film piece; S3: preparing the rubber compound film piece into the low-temperature-resistant acrylic vibrating diaphragm by air pressure forming.

7. The method for preparing a low-temperature resistant acrylic diaphragm according to claim 6, characterized in that, The preparation method of the rubber compound film piece in step S2 includes calendering or solution coating; The thickness of the rubber compound film piece is 20-200 μm.

8. The method for preparing a low-temperature resistant acrylic diaphragm according to claim 6 or 7, characterized in that, In step S3, the temperature of the air pressure forming is 180-200 ℃, the pressure is 0.2-2 Mpa, and the time is 40-150 s.

9. The low-temperature-resistant acrylic vibrating diaphragm prepared by the method of any one of claims 1-5 or 6-8 in the field of sound production devices.

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